5711 5715.output

* GB786119 (A)
Description: GB786119 (A) ? 1957-11-13
Improvements in or relating to polymers and their uses
Description of GB786119 (A)
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and information originating from other authorities than the EPO; in
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up-to-date or fit for specific purposes.
PATENT SPECIFICATION
7869119 Date of Application and filing Complete Specification: Sept
26, 1955.
N.27394155.
Application made in United States of America on Oct 8, 1954.
Complete Specification Published: Nov 13, 1957.
Index at acceptance:-Classes 2 ( 3), B 4 B, C 2 B 37 A 3, C 2 D 43 (A:
54), C 3 A 1; 2 ( 6), P 1 A, P 1 C( 8 B:
8 C: 20 C: 20 D 2: 20 D 3), Pl D(IC; 1 X; 5); and 98 ( 2), M.
International Classification:-CO 7 c, d CO 8 f G 03 f.
COMPLETE SPECIFICATION
Improvements' in or relating to 'Polymers, and their uses We, E I Du
PONT DE NEM Ou RS AND COMPANY, a Corporation organised and existing
under the Laws of the State of Delaware, United States of America, of
Wilmington, Delaware, United States of America, do hereby declare the
invention for which we pray that a patent may be granted to us, and

the method by which it is to be performed, to be particularly
described in and by the following statement: -
This invention relates to new polymers capable of addition
polymerization and more particularly to solvent-soluble linear
polymers which contain extralinear ethylenically unsaturated groups
and to their preparation and uses It further relates to solid
polyacetals of essentially linear hydroxyl polymers having a plurality
of intralinear vinyl alcohol (-CH CHOH-) groups and a plurality of
extralinear vinylidene (CH 2 = C<) groups in a conjugated system of
double bonds The invention also relates to polymerizable compositions
containing such a polyacetal and an addition-polymerization initiator
activatable by actinic light, and to sheet articles having a solid
layer of such composition.
According to a first feature of the present invention there is
provided a solid polyvinyl acetal of a linear polymeric alcohol of
high molecular weight having a large number of intralinear -CH CHOH
groups, said acetal containing a plurality of extralinear vinylidene
groups (Cil = C<) in a conjugated double bond system More
particularly, according to the invention, there are provided solid
polyacetals of essentially linear polymeric polyhydric alcohols having
a large number of recurring intralinear -CH CHOH units, said
polyacetals also comprising a plurality of extralinear vinylidene CH =
C< groups, said groups being in conjugated systems of double bonds, i
e, each having its double bond conjugated with another double bond,
the ratio of acetal groups to vinylidene groups in the polymer being
from about 10: 1 to about 1:10 Said polyacetals are soluble in
solvents, e g, water, methanol, ethanol, acetone and dioxane and form
self-supporting non-tacky films.
In the description of the invention which follows, the polymeric
polyhydric alcohol containing recurring intralinear -CHCHOHgroups will
often be referred to for the sake of brevity, simply as a " polyvinyl
alcohol " It will be understood that this term refers broadly to a
material having a plurality of polymerized vinyl alcohol,
-CHCHOIHunits, whether or not it is polyvinyl alcohol itself or one of
a number of related derivatives which contain a large number of
intralinear -CH CHOH groups, said material having in general a
molecular weight above 5,000 and, preferably between 5,000 and 50,000.
In a preferred form of the invention, the solid polyacetal is the
reaction product of a polyvinyl alcohol with a terminally unsaturated
aldehyde In this case, the aldehyde is so chosen that the resulting
polyacetal has a vinylidene group in a conjugated system even though
the aldehyde carbonyl is no longer present In other words, the
aldehyde must contain a terminal conjugated system which is separate
and independent from the aldehyde carbonyl, rather than a conjugated

system (as, for example, in acrolein or crotonaldehyde) which includes
the aldehyde carbonyl, since acetalization of the latter would give an
acetal no longer containing a conjugated system In polyacetals made
solely from aldehydes containing a vinylidene group in a conjugated
system independent from the carbonyl group, the ratio of acetal groups
to vinylidene groups is necessarily the same as the ratio of carbonyl
to vinylidene groups in the starting aldehyde, and is normally 1:1.
In another important embodiment of the invention, the solid polyacetal
is the reaction product of a polyvinyl alcohol with an aldehyde, which
may be saturated or unsaturated, and with an unsaturated reactant,
preferably an G-methylene carboxylic acid, capable of reacting
withlthe hvdroxvliups of the polys vinyl alcohol and having a
vinylidene group in a conjugated system of double bonds In polyacetals
of this type, the ratio of acetal groups to vinylidene groups can vary
widely; but for a good balance of properties, it should be within the
range of about 10: 1 to about 1:10.
The polyacetals of this invention always contain a plurality of
vinylidine groups in conjugated double bond systems This type of
structure has been found necessary for photopolymerization to take
place at a practical rate.
Polymers having unconjugated vinylidene groups, e g, allyl groups; or
having conjugated unsaturation, but not including a vinylidene, i e,
terminal methylene group, do not photopolymerize alone with the
conventional initiators, or, if they do, the polymerization rate is
too slow to be practical, especially for making printing reliefs Thus,
the polyacetals of this invention contain groups CIL = C-, where R is
hydrogen or a R monovalent radical, attached to an atom which is
itself doubly bonded to another group (i e, single atom or radical)
Preferably, the vinylidene group CH, = C is attached to carbon R
itself doubly bonded to carbon or oxygen It is necessary that a
plurality of such vinylidene groups be present in each polyacetal
molecule in order for the addition polymerization to produce a cross
linked structure.
The unsaturated polyvinyl acetals of this invention have good
film-forming properties, freedom from tackiness, resistance to
physical deformation, toughness and chemical stability and molecular
weights from 6,000 to 150,000.
In the polyacetals defined above the polyhydric alcohol portion of the
molecule is a hydroxyl polymer containing a large number of
intralinear -CELCHOH groups that is soluble in cold and/or hot water
or is hydrophilic in character, i e, forms films which do not dissolve
but are freely water-permeable and swell Such a polymer can be, for
example, polyvinyl alcohol itself, i e, a substantially completely
hydrolyzed polyvinyl carboxylate; or it may be a partially hydrolyzed

polymer of a vinyl carboxylate, particularly a vinyl ester of a
monocarboxylic acid of one to four carbon atoms, e g, vinyl formate,
vinyl acetate, vinyl chloroacetate, vinyl propionate or vinyl butyrate
The vinyl carboxylate should be sufficiently hydrolyzed so that the
-CH CHOH groups represent at least 50 % of the polymer chain, i e, for
every 100 chain atoms there are at least 25 hydroxyl groups Hydrolyzed
interpolymers of vinyl esters with minor proportions ( 25 % or less by
weight) of other polymerizable vinyl compounds, e g, vinyl chloride or
methyl methacrylate are suitable In particular, the hydrolyzed
olefin/vinyl esters interpolymers and especially the hydrolyzed
ethylene/vinyl acetate interpolymer having hydrophilic properties
described in Specification No 600,023 65 are useful The preferred
starting materials are the 50-100 % 3 hydrolyzed polyvinyl acetates.
In the polyvinyl acetals of this invention, it is preferred that
between about 10 %,o and 70 about 90 %-', are still more preferably
between %X O and 90 % of the hydroxyl groups of the polyvinyl alcohol
are acetalized If less than about 10 %', of the hydroxyl groups be
acetalized, the desired film toughness and resiliency 75
characteristic of the polyvinyl acetals are not realized, even when
many of the non-acetalized hydroxyl groups are replaced by other
groups, e g, acyl groups The higher limit of about 90 %,'
acetalization is in the neighbour 80 hood of that obtainable by
pushing the acetalization reaction to the maximum possible extent lsee
the papers by P J Flory in J Am.
Chem Soc 61, 1518 ( 1939) and 72, 5052 ( 1950), where it is shown by
statistical analy 85 sis that reactions involving pairs of
substituents X in a linear polymer composed of -CH 2-CHX units cannot
go to completion l As has already been stated, the polyvinyl 90
acetals of this invention may contain substituents besides the acetal
groups, such substituents being preferably saturated acyl groups
and/or unsaturated acyl groups, the latter furnishing the necessary
vinylidene 95 groups when the aldehyde furnishing the acetal groups
contains no vinylidene groups.
Other saturated or unsaturated substituents may also be present, e g,
ether groups.
Suitable inert substituents are carboxylic 100 ester groups, e g,
acetate, propionate and nbutyrate groups (preferably acetate groups),
which are originally present in the starting material, and acetal
groups derived from saturated aldehydes, preferably aromatic alde 105
hydes such as benzaldehyde, o-chlorobenzaldehyde and
p-benzoxybenzaldehyde In general, it is preferable that as many as
possible of the hydroxyl groups of the polyvinyl alcohol be
substituted in order to decrease the 110 water-sensitivity of the
products The most useful compounds are those in which at least %,

preferably at least 85 %J O of the hydroxyl groups are substituted.
The polyvinyl acetals of unsaturated alde 115 hydes may be prepared,
for example, by reacting, under acetal-forming conditions, a polyvinyl
alcohol with the appropriate aldehyde, or preferably with a monomeric
acetal thereof, e g, an acetal of an alkanol of 1 to 4 120 carbon
atoms, for example, methanol or ethanol, or of a 1,2 or 1,3 alkanediol
of 1 to 4 carbon atoms, such as ethylene glycol and propylene glycol,
until acetalization of the hydroxyl groups has proceeded to the
desired 125 extent Thus the reaction can be carried out 786,119
786,119 3 at a temperature from 40 C to 150 C, in the presence of an
acid, e g, hydrochloric, sulphuric, phosphoric, p-toluenesulphonic,
methanesulphonic acetic, chloroacetic or trifluoroacetic acid for a
period of 2 to 48 hours.
When the last of these organic acids is used, a slight amount of
esterification may take place Simultaneously with the acetalization
reaction or subsequently, additional substituents, preferably
saturated aliphatic acyl groups, can be introduced to decrease further
the amount of unreacted hydroxyl groups.
This can be done, for example, by carrying out the acetalization
reaction in a solvent medium which consists of or comprises a
saturated monocarboxylic acid, e g, glacial acetic acid, and may also
contain the anhydride of the same acid to absorb the water formed in
the reaction When it is desired to introduce the necessary vinylidene
groups through reactants other than the aldehyde, for example, through
an unsaturated carboxylic acid, this can be done by simultaneous or,
if desired, successive acetalization and acylation of the polyvinyl
alcohol with the appropriate dldehyde and the appropriate acid
containing a vinylidene group in a conjugated system of double bonds
The conventional acetalization and acylation procedures, catalysts and
conditions can be used.
Suitable unsaturated aldehydes are mentioned in the examples which
follow Other unsaturated mono-aldehydes (i e, aldehydes having a
vinylidene group in a conjugated structure independent of the aldehyde
carbonyl) which can be reacted, as such or in the form of a monomeric
acetal of a simple monohydric or dihydric alcohol, e g methanol,
ethanol or ethylene glycol, with a polymeric polyhydric alcohol to
form a polyvinyl acetal, include acrylamidoacetaldehyde, CH 2 =
CH-CO-NH-WC CHO;, (methacrylamido) propionaldehyde, CH 2 = CHCO-NH-C
Ho-C Ho-CHO; oc-vinylcrotonaldehyde, CHG = CH-C = C-CH,; CHO
c'.-phenylacrolein, CHG = C-CHO; o-acrylyloxybenzaldehyde, C Gl =
CH-CO-OQH,-CHO; m (a ethylacrylamido)benzaldehyde, CG Il = C-CO-NH-CGH
1CHO; 1-vinyl-4-naphthaldehyde, CH=CHZ c Ho
2-acrylamido-4-naphthaldehyde, CHO 4-vinyl-4 '-formylbiphenyl, and p-(
2-methacrylyloxyethoxy)benzaldehyde, CH = C-CO O c Hit 12 i-o HO CH 3

The preferred polyvinyl acetals are those derived from unsaturated
aldehydes having from 5 to 15 carbon atoms and particularly those
which are derived from an aromatic aldehyde, since films from such
polyvinyl acetals and their addition polymers are harder and
dimensionally more stable than others.
Within this embodiment of the invention, the preferred polyvinyl
acetals are those derived from aldehydes of the general formula:
CG = C-(R)12 (X-Q),,-RW-CHO, where y Y is hydrogen or alkyl of one to
two carbon atoms, i e, methyl or ethyl; R and R 1 are 70 aromatic
carbocyclic radicals, preferably arylene; X is carbonyl, -CO-, or
sulphonyl, -SO,-; Q is oxygen, -0-, or imino, -NH-; and m and N are 0
or 1, or their dimethyl, diethyl or ethylene glycol acetals 75 In the
embodiment of the invention wherein the conjugated vinylidene
unsaturation is furnished partly or entirely by a group other than the
acetal group, the unsaturated radical can be any non-acetal radical
containing a 80 vinylidene group which is part of a conjugated system
of double bonds For example, it can be a carboxylic acid ester group,
or a sulphonic acid ester group, or an ether group.
Preferably, it is a carboxylic acid ester group, 85 e.g, the ester
groups derived from acrylic, methacrylic, ac-ethylacrylic, j
3-vinylacrylics achloroacrylic, -phenylacrylic and p-vinylbenzoic
acids The most useful of such unsaturated substituents are the ester
radicals 90 corresponding to cc-methylene monocarboxylic acids, and
particularly to such acids having from three to five carbon atoms In
this type of polymers, the acetal groups can be supplied by any
aldehyde, which may be saturated or 95 unsaturated (in which latter
case conjugated vinylidene groups may be present in both the acetal
group and the auxiliary, e g, ester groups) Suitable aldehydes
include, for example, formaldehyde, acetaldehyde, propion 100 CH 2 =
CH CHO 786,119 aldehyde, isobutyraldehyde, furfural,
cyclohexylaldehyde, o-chlorobenzaldehyde, salicylaldehyde,
cinnamaldehyde, phenyl acetaldehyde, the naphthaldehydes,
1-chloro-2naphthaldehyde, anthraldehydes and benzamidoacetaldehydes
Preferably, the aldehyde furnishing the acetal groups is one having
from one to fifteen carbon atoms and more preferably, it is an
aromatic aldehyde of from seven to eleven carbon atoms in which the
aldehyde group is directly attached to annular carbon of an aromatic
carbocyclic ring.
According to a further feature of this invention there are provided
photopolymerisable compositions which comprise a polymeric polyvinyl
acetal as previously set forth, in admixture with an addition
polymerization initiator e g one which is activatable by actinic light
of wavelengths from 1800 to 7000 A In order to increase the storage
stability of the aforesaid compositions, it is desirable that they

contain a small amount, e.g, between 0 005 and 0 0201 by weight, of
one of the known polymerization inhibitors such as hydroquinone or
4-hydroxydiphenyl.
The said photopolymerizable compositions can be coated, cast or
extruded into a selfsupporting film Such a film may be laminated to a
suitable support or coated onto a suitable support, e g, metal sheet
or plate, hydrophobic film, impregnated paper or cardboard, or
laminated paper sheet and dried to remove water and/or an organic
solvent The resulting sheet elements, which bear a photopolymerizable
layer, can be used to prepare relief images, particularly printing
reliefs.
This invention accordingly includes photopolymerizable elements
suitable for the preparation of printing relief images Thus, it has
been found that letterpress printing plates which have uniform
printing height can be prepared by exposing with actir'ic light
through a process transparency, e g, a process negative or positive
(an image-bearing transparency consisting solely of substantially
opaque areas and substantially transparent areas where the opaque
areas are substantially of the same optical density, the socalled line
or halftone negative or positive) a photopolymerizable layer or
stratum comprising an unsaturated polyvinyl acetal of this invention
having intimately dispersed therethrough an addition polymerization
initiator activatable by actinic light, said layer or stratum being
superposed on a suitable adherent support, i e, adherent to the
photopolymerized composition, until substantially complete
crosslinking through the vinylidene groups take place in the exposed
areas, while substantially none takes place in the non-exposed areas,
and essentially completely removing the layer, e g, the
non-crosslinked polymer together with any admixed material, in said
non-exposed areas.
The ethylenically unsaturated polyvinyl acetal layer being transparent
to actinic light is photopolymerized, i e, crosslinked and rendered
insoluble, clear through to the support in the light-exposed areas,
whereas the areas not exposed remain in substantially their 70
original state, i e, no significant crosslinking takes place in the
areas protected by the opaque images in the process transparency.
The unexposed, and therefore non-crosslinked, material is then removed
by treating 75 the layer with a solvent for the original poly vinyl
acetal The crosslinked (exposed) portions being insoluble in
practically all solvents remain unattacked, forming the relief image.
The thickness of the photopolymerizable 80 layer is a direct function
of the thickness desired in the relief image and this will depend on
the subject being reproduced and particularly on the extent of the
non-printing areas.

In the case of photopolymerized halftones, the 85 screen used is also
a factor In general, the thickness of the polyvinyl acetal layer to be
photopolymerized on the base plate will vary from 0 003 to 0 25 inch
Layers ranging from 0.003 to 0 03 inch in thickness and usually 90
from 0 003 to 0 007 inch will be used for halftone plates Layers
ranging from 0 01 to about 0.06 inch in thickness will be used for the
majority of letterpress printing plates, including those wherein
halftone and line images are 95 to be combined, and it is with these
thicknesses that the process of this invention is particularly
effective Layers thicker than 0 05 -0.06 inch will be used for the
printing of designs and relatively large areas in letter 100 press
printing plates.
Actinic light from any source and of any type can be used in carrying
out this process.
The light may emanate from point sources or be in the form of parallel
rays or divergent 105 beams In order to reduce the exposure time,
however, it is preferred to use a broad light source, i e, one of
large area as contrasted to a point source of light, close to the
imagebearing transparency from which the relief 110 image is to be
made By using a broad light source, relatively close to the
image-bearing transparency, the light rays passing through the clear
areas of the transparency will enter as divergent beams into the
photopolymeriz 115 able layer, and will thus irradiate a continually
diverging area in the photopolymerizable layer underneath the clear
portion of the transparency, resulting in the formation of a polymeric
relief which is at its greatest width at 120 the bottom surface of the
photopolymerized layer, the top surface of the relief being the
dimensions of the clear area Such relief images are advantageous in
printing plates because of their greater strength and the 125 smooth
continuous slope of their sides as contrasted to the undercut or
jagged, irregular nature of the sides of photoengraved reliefs.
This is of importance since the smooth sloping reliefs obtained in
this process reduce or 130 786,119 eliminate the problem of
ink-build-up that is always encountered with photoengraved plates.
Inasmuch as the photopolymerization initiators or catalysts generally
exhibit their maximum sensitivity in the ultraviolet waveband, the
light source should furnish an effective amount of this radiation Such
sources include carbon arcs, mercury vapour arcs, fluorescent lamps
with special ultraviolet-light-emitting phosphors, argon glow lamps,
and photographic flood lamps Of these, the mercury vapour arcs,
particularly the sunlamp type, and the fluorescent sunlamps are most
suitable Groups of these lamps can be easily arranged to furnish the
broad light source required to give a frustrumshaped relief image of
good mechanical strength The sunlamp mercury vapour arcs are

customarily used at a distance of 7 to 10 inches from the
photopolymerizable layer On the other hand, with a more uniform
extended source of low intrinsic brilliance, such as a group of
contiguous fluorescent lamps with special phosphors, the plate can be
exposed within an inch of the lamps.
The base material used can be any natural or synthetic product,
capable of existence in film or sheet form and can be flexible or
rigid, reflective or non-reflective of actinic light.
Because of their generally greater strength in thinner form, e g,
foils, and readier adaptabilityfor usein printingpresses,it
ispreferable to use metals as the base materials However, where weight
is critical, the synthetic resins or superpolymers, particularly the
thermoplastic ones, are preferable base materials In those instances
where rotary press plates are desired both types of base or support
materials can be used to form flat relief plates which are then formed
to the desired shape The thermoplastic resins or high polymers are
particularly suitable base materials in such uses.
Such rotary press plates can also be prepared by using cylindrically
shaped base plates carrying the photopolymerizable compositions and
exposing them directly through a concentrically disposed image-bearing
transparency in like manner.
Suitable base or support materials include metals, e g, steel, zinc
and aluminium plates including grained zinc or aluminium plates,
sheets and foils, and films or plates composed of various film-forming
synthetic resins or high polymers, and in particular the vinylidene
polymers, e g, the vinyl chloride polymers, vinylidene chloride
copolymers with vinyl chloride, vinyl acetate, styrene, isobutylene
and acrylonitrile; and vinyl chloride copolymers with the latter
polymerizable monomers; the linear condensation polymers such as the
polyesters, e g, polyethylene terephthalate; the polyamides, e g,
polyhexamethylenesebacamide; polyester amides, e g,
polyhexamethyleneadipamnide/adipate Fillers or reinforcing agents can
be present in the synthetic resin or polymer bases, such as fibres
(synthetic, modified, or natural), e g, cellulosic fibres, for
instance, cotton, cellulose acetate, viscose rayon, paper, glass wool
or 70 nylon These reinforced bases may be used in laminated form.
When highly reflective bases and particularly metal base plates are
used, any oblique rays passing through clear areas in the image 75
bearing transparency will strike the surface of the base at an angle
other than 90 and after resultant reflection will cause polymerization
in non-image areas The degree of unsharpness in the relief
progressively increases 80 as the thickness of the desired relief and
the duration of the exposure increases It has been found that this
disadvantage can be overcome when the photopolymerizable composition

is deposited on a light-reflective base by 85 having an intervening
stratum sufficiently absorptive of actinic light so that less than
351,' of the incident light is reflected This lightabsorptive stratum
must be adherent to both the photopolymerized image and the base mat
90 erial A practical method of providing the layer absorptive of
reflected light, or non-halation layer, is to disperse a
finely-divided dye or pigment which substantially absorbs actinic
light in a solution or aqueous dispersion of a 95 resin or polymer
which is adherent to both the support and the photopolymerized image
and coating it on the support to form an anchor layer which is dried
If desired, where a transparent film or plate is used as a support for
the 100 photopolymerizable layer, the antihalation layer may be
disposed.
For use as photopolymerizable layers or printing relief images, the
compositions of this invention may contain, in addition to the un 105
saturated polyvinyl acetals, photopolymerizable monoethylenic monomers
which, when converted to linear polymers, serve to improve the
properties of the relief image, such as its solvent resistance Such
additional materials in 110 dude mono-unsaturated vinylidene monomers,
particularly the acrylic and a-alkylacrylic esters, nitriles and
amides, and specifically the acrylamide and methacrylamide These
additional components are preferably used in 115 amounts between 51 %
and 35 % of the weight of the total composition In use, they
photopolymerize in the exposed portions of the lightsensitive layer,
and any unpolymerized (i e, unexposed) portion of these added monomers
120 is readily removed by solvent treatment at the same time as the
non-crosslinked portions of the unsaturated polyvinyl acetal.
The photopolymerizable layers may also, if desired, comprise other
compatible monomeric 125 or polymeric poly-unsaturated materials
which, under the influence of actinic light, polymerize to crosslinked
insoluble polymers These agents improve the rate or extent of the
crosslinking throughout the photopolymerizable layer, and 130 their
presence facilitates the removal of the unexposed areas; they also
serve to plasticize the compositions when an initially softer
composition is desired A useful class of such matS erials are the
monomers or low polymers containing two terminal ethylenic
unsaturations, preferably in conjugated systems Suitable examples are
the methacrylic and acrylic acid diesters of ethylene glycol,
diethylene glycol, and the low molecular weight polyethylene glycols;
methacrylic and acrylic acid diesters of polymethylene glycols such as
trimethylene glycol; hexamethylene glycol, etc; divinylbenzene, crotyl
methacrylate, diallyl phthalate, diallyl maleate and triallyl
cyanurate These additional crosslinking agents are preferably used in
amounts between 1,% and 40 % by weight of the total compositions.

The photopolymerizable layers may also contain immiscible polymeric or
non-polymeric organic or inorganic fillers or reinforcing agents which
are essentially transparent, e g, the organophilic silicas,
bentonites, silica and nowdered glass, having a particle size less
than O 4 mil and in amounts varying with the desired properties of the
photopolymerizable layer.
Even when containing monomeric or low polymeric additives as described
above, the photopolymerizable compositions of this invention are
solids While their hardness varies from medium hard to very hard, they
are nevertheless substantially non-deformable under ordinary
conditions, and non-tacky Thus, they offer considerable physical
advantages over photopolymerizable compositions obtained as liquids,
viscous liquids or semi-solid gels from the standpoint of forming into
convenient elements for commercial printing use.
Practically any initiator or catalyst of addition polymerization which
is capable of initiating polymerization under the influence of actinic
light can be used in the photopolymerizable polymer-initiator layer of
this invention.
Because transparencies transmit both heat and light and the
conventional light sources give off heat and light, the preferred
initiators of addition polymerization are not activatable thermally
They should be dispersible in the unsaturated polyvinyl acetal to the
extent necessary for initiating the desired polymerization under the
influence of the amount of light energy absorbed in relatively short
term exposures Precautions can be taken to exclude heat rays so as to
maintain the photopolymerizable layer at temperatures which are not
effective in activating the initiator thermally, but they are
troublesome In addition, exclusion of heat rays makes necessary longer
exposure times since the rate of chain propagation in the
polymerization reaction is lowered at reduced temperatures For this
reason, the photoinitiators most useful for this process are those
which are not active thermally at temperatures belowabot 800 C These
photopolymerization initiators are used in amounts of from 0 05 to 51
% and preferably from 0 1 to 2 0 % based on the weight of the total
photopolymerizable composition.
Suitable photopolymerization initiators or catalysts include vicinal
ketaldonyl compounds 70 such as diacetyl and benzil; 9-k-etaldonyl
alcohols such as benzoin and pivaloin; acyloin ethers such as benzoin
methyl or ethyl ethers; ot-hydrocarbon substituted aromatic acyloins
including o methyl-benzoin, oa-allylbenzoin, and 75 2.-phenylbenzoin.
The solvent liquid used for washing or "developing " the plates made
from the photopolymerizable compositions of this invention must be
such that it has good solvent action on 80 the linear, i e,
non-crosslinked, polyvinyl acetal, and has little action on the

hardened image or upon the base material, non-halation layer, or
anchor layer in the time required to remove the non-crosslinked
portions Methanol 85 or ethanol, particularly the former, and mixtures
thereof with methyl or ethyl or propyl acetate, and especially ethyl
acetate/ethanol mixtures, have been found to be well suited for a
large variety of pliotopolymerizable com 90 positions A blend of about
75/25 by weight of ethyl acetate and ethanol has a boiling range which
is satisfactory since it is high enough to avoid blushing but at the
same time is low enough that excess solvent evaporates readily 95
Alcohol/water mixtures, e g, methanol/water mixtures, are desirable
solvents in some cases.
Low aliphatic ketones such as acetone, acetone/ water mixtures, e g,
an 8/1 mixture, and methyl ethyl ketone are very satisfactory sol 100
vents, as is also dioxane Other solvents such as propyl acetate,
toluene, ethylene glycol monoethyl ether and mixtures thereof, are
suitable but are not as convenient to use because of their lower
evaporation rate Mixtures of 105 chlorinated aliphatic hydrocarbons
such as dichloromethane, chloroform and carbon tetrachloride with
methanol are also useful, though less generally so.
By the use of the photopolyrnerizable com 110 positions of this
invention there is provided a simple, effective process for producing
letterpress printing plates from inexpensive materials and with a
marked reduction in labour requirements over the conventional photoen
115 graving procedure The images obtained are sharp and show fidelity
to the original transparency both in small details and in overall
dimensions In addition, the process allows the preparation of many
types of ruled line plates 120 which could ordinarily be handled only
by the tedious wax engraving technique Moreover, these
photopolymerized plates allow much more efficient use of valuable
press time since the flatness of the printing surfaces reduces the 125
amount of make-ready required on the press.
The smooth clean shoulders of the image minimize ink build-up during
use and save much of the time spent in cleaning operations during a
press run Another important advantage arises 130 786,119 706,119 from
the fact that the resilience and abrasion resistant characteristics of
the photopolymerized printing plates make the plate more durable in
use than ordinary metal photoengravings In fact, under optimum
conditions the photopolymerized printing plates show wear resistance
equivalent to that of the expensive nickel-faced electrotypes An
important commercial advantage is their lightness in weight.
The photopolymerized printing plates can serve as originals for the
preparations of stereotypes or electrotypes although in the latter
case if only duplicates are desired, it is much more convenient and
economical to make duplicate photopolymerized plates Curved plates for

use on rotary presses can be prepared easily by bending the flat
plates It may be desirable in some cases to heat the plates
sufficiently (generally from 100 to 1200 C) to soften the image layer
It is also possible to prepare curved plates directly by
polymerization against a curved negative surface.
The printing elements of this invention can be used in all classes of
printing but are most applicable to those classes of printing wherein
a distinct difference of height between printing and non-printing
areas is required These classes include those wherein the ink is
carried by the raised portion of the relief such as in dry-offset
printing, ordinary letterpress printing, the latter requiring greater
height differences between printing and non-printing areas and those
wherein the ink is carried by the recessed portions of the relief such
as in intaglio printing, e g, line and inverted halftone The plates
are useful for multicolour printing.
The use of compositions containing the unsaturated polyvinyl acetals
of this invention as photopolymerizable printing relief elements has
been described at length in view of its importance These acetals,
however, are also suitable for many other applications in which
readily crosslinkable polymers are useful, such as the preparation of
filaments, foils, coatings, pellicles, sheets and other shaped or cast
objects of excellent hardness and scratch resistance.
The following examples will serve to illustrate various aspects of the
present invention but are not to be regarded as limiting it in any 5)
way, the parts given are by weight.
EXAMPLE I.
A Preparation of rn-Methacrylamidobenzaldehyde Ethylene Glycol Acetal.
To a mechanically stirred solution of 50 parts of rn-aminobenzaldehyde
ethylene glycol acetal (Specification No 638,895) in 40 parts of
acetone and 5 parts of ice, there was added dropwise a solution of 31
parts of methacrylyl chloride in 30 parts of anhydrous dioxane The
temperature was maintained at 0-5 C by means of external cooling and
the p H of the reaction was kept at 7-9 by the portionwise addition of
a solution of 50 parts of potassium carbonate and 50 parts of water
The reaction product, mn methacrylamidobenzaldehyde 65 ethylene glycol
acetal, separated as a colourless crystalline solid The reaction
mixture was stirred for an additional period of 30 minutes and was
diluted to a volume of 500 parts with cold water The
m-methacrylamidobenzalde 70 hyde ethylene glycol acetal was collected
and washed with cold water and the moist filter cake was dissolved in
methylene chloride The organic layer was separated, dried with
anhydrous magnesium sulphate and concentrated 75 by evaporation of the
solvent until the internal temperature reached 48 C The mixture was
cooled slightly and diethyl ether was added until crystals appeared

After cooling to O C.
the colourless crystals of m-methacrylamido 80 benzaldehyde ethylene
glycol acetal were collected, washed with cold diethyl ether and dried
The yield of colourless crystals melting at 113-114 C was 50 parts.
Anal Calc'd for CH 11,ON: C, 66 92; 85 11, 6 49; N, 6 01 Found C, 66
67; H, 6 64; N, 6 06.
B Preparation of m-Methacrylamidobenzaldehyde Polyvinyl Acetal.
A mixture of 5 parts of an 86-90 % hydro 90 lyzed polyvinyl acetate
having a viscosity of 4-6 centipoises (for a 41 % water solution at C)
(a polyvinyl alcohol commercially sold under the trade mark " Elvanol
" 51-05), 2 parts of mn methacrylamidobenzaldehyde 95 ethylene glycol
acetal (sufficient to react with about 19 % of the hydroxyl groups
present), 20 parts of glacial acetic acid, 1 5 parts of
trifluoroacetic acid, and 0 03 part of hydroquinone was stirred at 85
C for 1 5 hours The m 100 methacrylamidobenzaldehyde polyvinyl acetal
was precipitated from the resulting pale yellow solution by addition
of about 30 parts of diethyl ether followed by the addition of 20
parts of petroleum ether The solvents were decanted 105 from the
precipitated product and the heavy, gummy mass was washed with ether
The precipitated polyvinyl acetal was dissolved in about 15 parts of
methanol and reprecipitated by the addition of 30-40 parts of ether
The 110 solution and precipitation processes were repeated a second
and third time After the third precipitation from methanol, the
m-methacrylamidobenzaldehyde polyvinyl acetal was dissolved in
methanol and the resulting solution 115 was filtered, the filtered
solution coated on a glass plate and the methanol was allowed to
evaporate leaving a colourless, transparent, flexible film The
nitrogen content of the solvent free polymer was 1 91 %, indicating
that 120 essentially all of the monomeric m-methacrylamidobenzaldehyde
ethylene glycol has been converted to the polyvinyl acetal This
polymer was a polyvinyl acetal containing, besides unreacted hydroxyl
groups in intralinear 125 -CH CHOH groups,
m-methacrylamidobenzaldehyde acetal groups of the structure:
ci-Cai Cu Cii-c I 0 O ctj Lt N-co-f =Cfi 2 CH 3 and acetoxy groups,
the latter being present in the original partially hydrolyzed
polyvinyl acetate and also resulting from esterification during the
acetalization reaction The polymer was soluble in methanol, ethanol
and ethylene glycol but was insoluble in esters, e g, ethyl acetate
and methyl acetate, and was insoluble in water.
C Preparation of Printing Relief Images.
To a methanol solution of the m-methacrylamidobenzaldehyde polyvinyl
acetal, prepared as described under Section B, there was added 1,' of
the solids content of benzoin methyl ether There was also added 0 01
%, based on the solids content, of hydroquinone to prevent premature

polymerization and insolubilization.
The resulting solution was cast on glass plates to give films having a
thickness of 0 010-0 020 inches after evaporation of the solvent The
methanol was allowed to evaporate at room temperature in subdued light
The resulting solid, transparent, tack-free films adhered tenaciously
to glass The polyvinyl acetal layer was placed in intimate contact
with a suitable line negative, the resulting assembly was placed on a
turntable on a piece of black paper-toserve as an antihalation layer
and exposed for a period of 15 minutes under four mercury vapour
sunlamps suitably arranged at a distance of 12-14 inches from the
surface of the layer After removal of the negative, the unexposed
material was removed by washing in methanol for 5-10 minutes The
resulting plate had scratch-resistant printing relief images of
excellent sharpness having deep recess areas.
EXAMPLE II.
A Preparation of p-Vinylbenzaldehyde Ethylene Glycol Acetal.
To a mechanically stirred solution of 27 parts of 85 % potassium
hydroxide in 160 parts of 95 M% ethanol at 600 C was added 80 parts of
p ( 2-bromoethyl)benzaldehyde ethylene glycol acetal The temperature
rose to 70 C.
and crystals of potassium bromide separated.
The reaction mixture was maintained at 70 C for 15 minutes and most of
the ethanol was removed by distillation under reduced pressure.
The residue was diluted with water, the organic material was extracted
with diethyl ether and after concentration of the ether extract, the
residual Pf-vinylbenzaldehyde ethylene glycol acetal was distilled The
fraction boiling at 1050 C at 1 mm was recovered as substantially pure
p-vinylbenzaldehyde ethylene glycol acetal.
Anal Calc'd for,1 IH O 2: C, 74 96; H, 6.87 Found: C, 75 19; H 7 29.
B Preparation of p-Vinylbenzaldehyde Polyvinyl Acetal.
A mixture of 5 parts of the hydrolyzed polyvinyl acetate used in
Example I, 2 5 parts of p-vinylbenzaldehyde ethylene glycol acetal
(sufficient to react with about 32 %o of the hydroxyl groups present),
20 parts of glacial acetic acid, 1 5 parts of trifluoroacetic acid and
0 03 part of hydroquinone was stirred at 85-87 ' C for two hours The
p-vinylbenzaldehyde polyvinyl acetal thus obtained was freed of
hydroquinone and acetic acid essentially as described in Example I,
Section B This polymer was a polyvinyl acetal containing, besides
residual hydroxyl groups in intralinear -CGI GCHOH groups, acetoxy
groups from the starting material and from further esterification by
the acetic acid, and p-vinylbenzaldehyde acetal units of the formula:
CH-Clif C A-CH 2 / CH=C"I" In the latter groups, the vinylidene
group is conjugated with a benzenoid double bond.

To the methanol solution of p-vinylbenzaldehyde polyvinyl acetal
obtained as described under Section B was added 0 07 parts of benzoin
methyl ether and 0 01 %, by weight of the solids content, of
hydroquinone to stabilize against premature gelation, and the
resulting solution was cast on glass plates After removal of the
methanol by evaporation, a transparent, hard film was obtained that
adhered tenaciously to glass Exposure under a suitable line negative
and removal of unexposed material essentially as described in Example
I, Section gave scratch-resistant printing relief images of excellent
sharpness having deep recess areas.
EXAMPLE III.
A Preparation of mz-(p-Vinylbenzenesulphonamido)benzaldehyde Ethylene
Glycol Acetal.
To a solution of 150 parts of m-aminobenz 100 aldehyde ethylene glycol
acetal, 240 parts of acetone, 150 parts of water and 150 parts of
potassium carbonate at 5-7 ' C, there was added the sulphonyl chloride
obtained by the chlorosulphonation of 200 parts of ( 2-brom 105
ethyl)benzene as described by Inskeep and Deanin, I Amt Chen Soc 69,
2237 ( 1947).
The resulting reaction mixture was stirred at 5-10 C for 20 hours; it
was then diluted with water and the liquid organic layer was 110
786,119 recess areas An excellent relief printing image was obtained
by adding to the photopolymerizable composition 25 % (based on the
weight of 60 the polyvinyl acetal) of the bis-methacrylate ester of
polyethylene glycol of average molecular weight 200, as a plasticizer
and additional crosslinking agent.
EXAMPLE IV 65
A Preparation of m-Methacrylamidobenzaldehyde Polyvinyl Acetal
Containing Acrylyloxy Groups.
Example I, 4 parts of 70 m-methacrylamidobenzaldehyde ethylene glycol
acetal (enough to react with about 19 % of the hydroxyl groups
present), 40 parts of acrylic acid (a large excess over the calculated
amount), 3 parts of trifluoroacetic acid and 75 0.06 part of
hydroquinone was stirred at 90950 C for three hours The resulting
polymer was freed of excess hydroquinone and acrylic acid essentially
as described in Example I, Section B Evaporation of the methanol solu
80 tion gave a clear hard film This polymer was a polyvinyl acetal
containing, besides hydroxyl groups in intralinear -CH CHOH groups,
acetoxy groups, acrylyloxy groups and mmethacrylamidobenzaldehyde
acetal groups 85 B Preparation of Printing Relief Images.
To 50 parts of the methanol solution containing approximately 16 parts
of the above polyvinyl acetal was added 0 18 part of benzoin methyl
ether and about 0 0015 part of hydro 90 quinone and the resulting

solution was cast on glass plates After removal of the methanol at
room temperature in subdued light, the layer of solid polymer was
exposed under a line negative and unexposed material was removed 95
essentially as described in Example I, Section C Scratch-resistant
printing relief images of excellent sharpness with deep recess areas
remained adherent to the surface of the glass plate after removal of
the unexposed material 100 EXAMPLE V.
A Preparation of Benzaldehyde Polyvinyl Acetal Containing Acrylyloxy
Groups.
Example I, 40 parts of 105 acrylic acid (a large excess), 1 2 parts of
benzaldehyde (enough to react with about 12 % of the hydroxyl group),
3 parts of trifluoroacetic acid and 0 03 part of hydroquinone was
stirred at 90-95 C for three hours The resulting 110 polymer was freed
of excess hydroquinone, acrylic acid and benzaldehyde essentially as
described in Example I, Section B This polymer was a polyvinyl acetal
containing, in addition to hydroxyl groups in intralinear 115 -CHCHOH
groups, acetoxy groups, acrylyloxy groups and benzaldehyde acetal
groups In this case, the vinylidene unsaturation was provided solely
by the acrylyloxy groups 120 B Preparation of Printing Relief Images.
separated and washed with water by decantation The resulting
low-melting m-lp-( 2bromoethyl) benzenesulphonamidolbenzaldehyde
ethylene glycol acetal, without further purification, was added to a
solution of 165 parts of 85 % potassium hydroxide in 700 parts of 95
i% ethanol at 50 C The temperature rose to 67 C and crystals of
potassium bromide separated After the mixture had been maintained at
65-69 C for 65 minutes, most of the ethanol was removed by
distillation under reduced pressure and the residue was diluted with
water The resulting solution was acidified by the addition of acetic
acid, whereupon an oil separated that soon solidified Crystallization
of the solidified product from a large volume of methylene chloride
gave 145 parts of colourless crystals of
m-(p-vinylbenzenesulphonamido)benzaldehyde ethylene glycol acetal,
melting at 140-142 C.
Anal Calc'd for C 17 H,0 NS C, 6159; H, 5 18; N, 4 23; S, 9 68 Found:
C, 61 80; H, 5 14; N, 4 03; S, 9 59.
B Preparation of m-(p-Vinylbenzenesulphonamido)benzaldehyde Polyvinyl
Acetal.
Example I, 15 parts of m-(p-vinylbenzenesulphonamido)benzaldehyde
ethylene glycol acetal (sufficient to react with about 201 % of the
hydroxyl groups present), 100 parts of glacial acetic acid, 7 5 parts
of trifluoroacetic acid and 0 2 part of hydroquinone was stirred at
85-87 C for two hours The resulting

m-(p-vinylbenzenesulphonamido)benzaldehyde polyvinyl acetal was freed
of excess hydroquinone and acetic acid essentially as described in
Example I, Section B This polymer was a polyvinyl acetal having,
besides residual hydroxyl groups in intralinear -CHCHOH-, groups,
acetoxy groups and acetal groups of the formula:
0 O -C,-NH 2-5 2 C D-H 2 H C Preparation of Printing Relief Images.
To 30 parts of the methanol solution containing approximately 12 parts
of m-(p-vinylbenzene sulphonamido)benzaldehyde polyvinyl acetal
prepared as described under Section B, there was added 0 12 part of
benzoin methyl ether and about 0 001 part of hydroquinone and the
solution was cast on glass plates After evaporation of the methanol, a
transparent, non-tacky solid layer was obtained that adhered
tenaciously to glass Exposure under a suitable line negative and
removal of unexposed material essentially as described in Example I,
Section C, gave a scratch-resistant printing relief image of excellent
sharpness having deep 786,119 To the methanol solution of the above
polyacetal was added 0 18 part of benzoin methyl ether and O 01 % of
hydroquinone, based on the solids content, and the resulting solution
was cast on glass plates After removal of the methanol by evaporation
at room temperature, a non-tacky solid layer was obtained Exposure
under a suitable negative and removal of unexposed material
essentially as described in Example I, Section C, gave soft, highly
resilient images.
EXAMPLE VI.
A Preparation of mii-Methacrylamidobenzaldehyde Polyvinyl Acetal.
A mixture of 50 parts of the polyvinyl alcohol (hydrolyzed polyvinyl
acetate) used in Example I, 37 5 parts of
rn-methacrylamidobenzaldehyde ethylene glycol acetal (sufficient to
react with about 361 % of the hydroxyl groups present), 200 parts of
glacial acetic acid, 15 parts of trifluoroacetic acid and 0 3 parts of
hydroquinone was stirred at 85-87 C for one hour Twenty ( 20) parts of
acetic anhydride was added dropwise during the course of 30 minutes
and the reaction was continued for an additional period of 30 minutes
The polyvinyl acetal was freed of excess hydroquinone and acetic acid
essentially as described in Example I, Section B There was obtained
300 parts of solution of the polyvinyl acetal containing 31 '% solids
The solid had a nitrogen content of 2 41 % (theoretical 2 42 %) This
polymer was essentially similar to that of Example I except that both
the extent of acetalization and the extent of acetylation were higher
From the weight of polyvinyl acetal obtained and its nitrogen content,
it was calculated that it contained, by weight, 44 5 % of nt
methacrylamidobenzaldehyde polyvinyl acetal, 46 C% of polyvinyl
acetate and 9 5 % of polyvinyl alcohol This polymer was, therefore, a
polyvinyl alcohol in which about 31 % of the hydroxyl groups were

acetalized and about 501 % of them acetylated.
B Preparation of Printing Relief Images.
To 20 parts of the above solution was added 0.06 part of benzoin
methyl ether and 0 01 % of hydroquinone, based on the solids content,
and the solution as cast on glass plates Removal of the methanol by
evaporation at room temperature gave clear hard films having a
thickness of 0 028-0 30 inch Exposure of the polymer under a line
negative and removal of the unexposed material essentially as
described in Example I, Section C, gave scratch-resistant printing
relief images of excellent sharpness with deep recess areas A similar
printing relief was obtained when 20 parts of the methanol solution of
the m-methacrylamidobenzaldehyde polyvinyl acetal was mixed with 0 08
part of benzoin methyl ether and 1 8 parts of the bismethacrylate
ester of a polyethylene glycol of average molecular weight 200, to act
as plasticizer and additional crosslinking agent.
The next three examples illustrate the use of a photopolymerizable
monomer in admixtures with the addition-polymerizable polyvinyl acetal
in elements suitable for the preparation of printing relief images The
resulting compositions had faster photopolymerization rates 70 than
the unmodified ones and the images were more solvent-resistant.
EXAMPLE VII.
To 20 parts of a methanol solution of a mmethacrylamidobenzaldehyde
polyvinyl acetal 75 containing 44 {% solids and prepared essentially
as described in Example I, there was added 0 1 part of benzoin methyl
ether, about 0.0009 part of hydroquinone and 2 parts of acrylamide The
resulting solution was cast on 80 glass plates and after removal of
the methanol by evaporation at room temperature, a clear, hard,
non-tacky film 0 015-0 020 inch thick was obtained Exposure of the
film under a line negative and removal of unexposed material 85
essentially as described in Example I, Section C, gave a
scratch-resistant printing relief image of excellent sharpness with
deep recess areas.
EXAMPLE VIII.
To 10 parts of a methanol solution of a m 90
methacrylamidobenzaldehyde polyvinyl acetal containing 40 % solids and
prepared essentially as described -in Example I, there was added 0 12
part of benzoin methyl ether, about 0.0004 part of hydroquinone, 0 5
part of acryl 95 amide and 0 5 part of methacrylamide The re sulting
solution was cast on glass plates at such a thickness as to give films
having a thickness of 0 015-0025 inch after removal of the methanol by
evaporation at room temperature 100 Exposure of the resulting hard,
non-tacky, transparent film under a negative and removal of the
unexposed material essentially as described in Example I, Section C,
gave scratchresistant printing relief images of excellent 105

sharpness with deep recess areas.
EXAMPLE IX.
To 20 parts of the same methanol solution as used in Example VIII,
there was added 0 65 part of benzoin methyl ether, about 0 0008 part
110 of hydroquinone, 1 7 parts of the bis-methacrylate ester of
polyethylene glycol (average molecular weight 200) and 1 part of
acrylamide The resulting solution was cast on glass plates at such a
thickness as to give films hav 115 ing a thickness of 0 025-0 030
inch, after removal of the methanol by evaporation at room temperature
Exposure of the resulting hard, non-tacky, transparent film under a
line negative and removal of the unexposed material 120 essentially as
described in Example I, Section C, gave scratch-resistant printing
relief images of excellent sharpness with deep recess areas.
EXAMPLE X.
A Preparation of n-Butyraldehyde Polyvinyl 125 Acetal Containing
Methacrylyloxy Groups.
A mixture of 5 parts of the polyvinyl acetal obtained by acetalizing
polyvinyl alcohol with n-butyraldehyde until about 80 %c, of the
hydroxyl groups are reacted, 25 parts of meth 130 786,119 vents at
room temperature Exposure of the resulting hard, transparent film
under a line negative and removal of the unexposed material
essentially as described in Example I, Section C, except that a
mixture of methylene chlorideethanol was used in place of methanol,
gave hard printing relief images of excellent sharpness.
acrylic acid, 1 5 parts of trifluoroacetic acid and 0 05 part of
hydroquinone was stirred at 85-90 C for one hour The polymer was
precipitated from the resulting clear solution by the addition of
ether and freed of excess hydroquinone and methacrylic acid
essentially as described in Example I, Section B Evaporation of a test
portion of the methanol solution on a glass plate gave a colourless,
transparent, tough film This polymer was a polyvinyl acetal
containing, besides hydroxyl groups in intralinear -CH 2 CHOH groups,
methacrylyloxy groups and n-butyraldehyde acetal groups.
To the methanol solution of the polyvinyl acetal prepared as described
in Section A, there was added 0 05 part of benzoin methyl ether and 0
01 % of hydroquinone, based on the solids content, and the resulting
solution was cast on glass plates to form films having a thickness of
0.010-0 015 inch, after removal of the methanol by evaporation at room
temperature Exposure of the resulting hard, transparent film under a
line negative and removal of the unexposed material essentially as
described in Example I, Section C, gave images which, while useful as
printing reliefs, were slightly attacked by the methanol used to
removed the unexposed material.

EXAMPLE XI.
A Preparation of m-Methacrylamidobenzaldehyde Polyvinyl Acetal.
A mixture of 5 parts of the polyvinyl alcohol used in Example I, 20
parts of m-methacrylamidobenzaldehyde ethylene glycol acetal (nearly
twice the amount calculated to react with all the hydroxyl groups
present), 20 parts of ethanol, 0 1 part of hydroquinone and 0 5 part
of a 10 % aqueous solution of sulphuric acid was stirred at 60-65 C
for one hour whereupon 2 5 parts of a 101 % solution of triethylamine
in methanol was added To the resulting solution was added diethyl
ether to precipitate the polyvinyl acetal The excess hydroquinone was
removed essentially as described in Example I, Section B, except that
a mixed solvent of 3 parts of methylene chloride and 1 part of
ethanol, by volume, was used in place of the methanol in Example I,
Section B. This polyvinyl acetal was similar in structure to that of
Example I except that it contained less acetoxy groups and more acetal
groups.
Analysis of a portion of the solid polymer gave a nitrogen content of
4 241 % This shows that about 85 % of the available hydroxyl groups
were acetalized, since complete acetalization would correspond to 4 96
% nitrogen.
To the methylene chloride-ethanol solution of the polyvinyl acetal
prepared under Section A was added 0 02 part of benzoin methyl ether
and 0 011 % of hydroquinone, based on the solids content, and the
solution was cast on glass plates to give films having a thickness of
0 010-0 015 inch on evaporation of the solEXAMPLE XII.
A Preparation of p-Vinylbenzaldehyde Poly 75 vinyl Acetal.
A mixture of 5 parts of the polyvinyl alcohol used in Example I, 15
parts of p-vinylbenzaldehyde ethylene glycol acetal (nearly twice the
amount calculated to react with all the 80 hydroxyl groups present),
20 parts of ethanol, 0.1 part of hydroquinone and 05 part of 10 Q%
aqueous sulphuric acid was stirred at 60-65 C for one hour whereupon 2
5 parts of a 10 i% solution of triethylamine in methanol was 85 added
The polyvinyl acetal was precipitated by the addition of diethyl ether
and freed of excess hydroquinone essentially as described in Example
I, Section B, except that a mixed solvent of 3 parts of ethyl acetate
and 1 part of 90 ethanol, by volume was used in place of methanol
Casting a test portion of the solution of the polyvinyl acetal on a
glass plate gave a hard, transparent flexible film This polymer was
similar in structure to that of Example II 95except that it contained
less acetoxy groups and more acetal groups.
To the ethyl acetate-ethanol solution of the polyvinyl acetal prepared
in Section A was 100 added 0 1 part of benzoin methyl ether and 0.011

% of hydroquinone, based on the solids content, and one-half of the
solution was cast on glass plates to give films having a thickness of
0 010-0 015 inch after evaporation of the 105 solvents at room
temperature To the remainder of the original polymer solution was
added an additional quantity of 0 02 part of benzoin methyl ether and
1 7 parts of the bismethacrylate ester of polyethylene glycol of 110
molecular weight 200 This solution was also cast on glass plates as
previously described The resulting hard, non-tacky films were exposed
under a line negative and the unexposed material was removed
essentially as described in 115 Example I, Section C, except that a
mixed solvent, ethyl acetate-ethanol ( 3 to 1 by volume) was used in
place of methanol Both compositions gave scratch-resistant printing
relief images of good sharpness with deep recess 120 areas.
EXAMPLE XIII.
A Preparation of m-Methacrylamidobenzaldehyde/o-chlorobenzaldehyde
Polyvinyl Acetal.
A mixture of 15 parts of medium viscosity 125 completely hydrolyzed
polyvinyl alcohol (commercially sold under the trade mark " Elvanol "
90-25), 13 parts of m-methacrylamidobenzaldehyde ethylene glycol
acetal, 10 5 parts of a-chlorobenzaldehyde, 100 parts of glacial 130
786,119 acetic acid, 7 5 parts of trifluoroacetic acid, 30 parts of
chloroform and 0 1 part of hydroquinone was stirred at 65 C for 1 5
hours.
The polyvinyl acetal was freed of hydroquinone and acetic acid
essentially as described in Example I, Section B, except that dioxane
was used as the solvent in place of methanol There was obtained 198
parts of dioxane solution having a solids content of 19 % Analysis of
a portion of the solvent-free film gave a nitrogen content of 2 401 %
and a chlorine content of 5.88 % These figures indicate that the
polymer contained 44 5 % rn-methacrylamidobenzaldehyde polyvinyl
acetal, 353 % o-chlorobenzaldehyde polyvinyl acetal, 17 8 % of
polyvinyl acetate and 2 81 % of unchanged polyvinyl alcohol This
polymer was a polyvinyl alcohol derivative in which about 72 % of the
hydroxyl groups were acetalized and about 22 % of them were
acetylated.
To 53 parts of the above dioxane solution of the polyvinyl acetal was
added 0 1 part of benzoin methyl ether and 0 001 part of hydroquinone
and the solution was cast on glass plates Removal of the dioxane at
room temperature in subdued light gave a clear, transparent flexible
film Exposure of the film under a suitable line negative and removal
of unexposed material essentially as described in Example I, Section
C, gave a scratch-resistant image of excellent sharpness with deep
recess areas.

EXAMPLE XIV.
Preparation of m Methacrylamidobenzaldehyde/3,4-dichlorobenzaldehyde
Polyvinyl Acetal.
A mixture of 10 parts of completely hydrolyzed high viscosity
polyvinyl alcohol (commercially sold under the trade mark " Elvanol "
72-60), 15 parts of rn-methacrylamidobenzaldehyde ethylene glycol
acetal, 8 8 parts of 3,4-dichlorobenzaldehyde, 125 parts of glacial
acetic acid, 7 5 parts of trifluoroacetic acid and 0 1 part of
hydroquinone was stirred at 65 C for 1 5 hours On addition of diethyl
ether to the vigorously stirred reaction mixture, the polyvinyl acetal
separated as a finely divided solid The solid was collected, washed
with diethyl ether and slurried for 15 minutes with diethyl ether The
solid polymer was again collected and slurried for 30 minutes with
diethyl ether, and the slurrying steps were repeated a third and
fourth time with fresh ether to remove the hydroquinone and acetic
acid.
The resulting dry powder ( 25 parts) had a nitrogen content of 2 55 %,
and a chlorine content of 9 781 % These figures indicate that the
polymer contained 47 % rz-methacrylamidobenzaldehyde polyvinyl acetal,
33 9 i% 3,4-dichlorobenzaldehyde polyvinyl acetal, 12.4 % of polyvinyl
acetate and 6 7 i% of unchanged polyvinyl alcohol This polymer was a
polyvinyl alcohol in which about 69 % of the hydroxyl groups were
acetalized and about % of them were acetylated The polymer was soluble
in dioxane and chloroform-dioxane mixtures.
EXAMPLE XV.
A Preparation of Methacrylamidoacetaldehyde 70 Ethylene Glycol Acetal.
To a solution of 31 parts of aminoacetaldehyde ethylene glycol acetal
(prepared as described in Organic Syntheses, Vol 24, p 3) and 50 parts
of water cooled to 0-5 C was 75 added dropwise a solution of 35 parts
of methacrylyl chloride in 35 parts of dioxane.
The p H of the reaction mixture was maintained at 7-9 by the
portionwise addition of a solution of 42 parts of potassium carbonate
80 in 40 parts of water After the addition of the acid chloride was
complete, the reaction mixture was allowed to warm to 250 C during the
course of one hour and stirred an additional period of two hours at
250 C The 85 reaction mixture was extracted several times with ether,
the ethereal solution was dried over magnesium sulphate and after
filtering, the solution was concentrated Distillation of the residue
from 0 1 part of hydroquinone gave 40 90 parts of
methacrylamidoacetaldehyde ethylene glycol acetal boiling at 120-122 C
at 1 mm.
pressure.
Anal Calc'd for C 8 H 1,0,N: C, 56 11; H, 7.66 Found: C, 56 34; H 7 75
95 B Preparation of Methacrylamidoacetaldehyde Polyvinyl Acetal.

A mixture of 10 parts of 86-89 %' hydrolyzed low viscosity polyvinyl
alcohol, 14 parts of methacrylamidoacetaldehyde ethylene 100 glycol
acetal, 0 3 part of hydroquinone, 50 parts of glacial acetic acid and
0 4 part of p-toluene-sulphonic acid monohydrate was stirred at 650 C
for 1 25 hours A solution of 2.5 parts of 10 % triethylamine in
methanol 105 was added to neutralize the sulphonic acid catalyst and
the methacrylamidoacetaldehyde polyvinyl acetal was precipitated by
the addition of diethyl ether and freed of hydroquinone and acetic
acid essentially as described 110 in Example I, Section B There was
obtained 58 parts of methanol solution of the polyvinyl acetal, having
a solids content of 32 % The solid polymer had a nitrogen content of
5.21 % On the basis of these figures, the solid 115 polyvinyl acetal
had a methacrylamidoacetaldehyde polyvinyl acetal content of 73 5 %, a
polyvinyl acetate content of 19 % and unchanged polyvinyl alcohol
content of 7 6 %.
This polymer was a polyvinyl alcohol deriva 120) tive in which about
19 % of the intralinear -CHICHOH groups were acetylated and about 65 %
of them were replaced by acetal units of the formula:
-CH-CH p CH-CH 2 f o',CH 11 C Hif NH-CO,-C= CH 2 ONCM 786,119 786,119
To 31 parts of the above methanol solution, there was added 0 1 part
of benzoin methyl ether and 0 001 part of hydroquinone and the
resulting solution was cast on glass plates.
Removal of the methanol at room temperature in subdued light gave a
clear, transparent flexible film Exposure under a suitable line
negative essentially as described in Example I, Section C, gave hard,
scratch-resistant printing relief images of excellent sharpness with
deep recess areas.
EXAMPLE XVI.
A Preparation of p-Methacrylyloxybenzaldehyde.
To a solution of 73 parts of p-hydroxybenzaldehyde and 71 parts of
anhydrous triethylamine in 200 parts of methylene chloride, there was
added dropwise, with stirring, a solution of 73 parts of methacrylyl
chloride in parts of methylene chloride, the temperature being
maintained at 15-20 C by means of external cooling The mixture was
stirred at 20-25 C for an additional period of one hour after the
addition of the acid chloride was complete 200 parts of water
containing 10 parts of concentrated hydrochloric acid was added and
the organic layer was separated and washed twice with 1 % hydrochloric
acid After drying and adding 0 2 parts of hydroquinone, the solution
was concentrated and the residue was distilled There was obtained 86
parts of p-methacrylyloxybenzaldehyde boiling at 115-120 C at 1 mm.
and melting at 27-29 C.
Anal Calc'd for Cj HJO,: C, 69 44; H, 5.30 Found: C, 69 49; H, 5 43.

B Preparation of p-Methacrylyloxybenzaldehyde Polyvinyl Acetal.
A vessel containing a mixture of 10 parts of 86-89 % hydrolyzed
polyvinyl acetate (a low viscosity polyvinyl alcohol), 25 parts of p
methacrylyloxybenzaldehyde (an excess over the quantity required to
acetalize all the hydroxyl groups), 80 parts of glacial acetic acid, 6
parts of trifluoroacetic acid, and 0 1 part of hydroquinone was placed
in a water bath at 600 C After stirring for 10 minutes at a bath
temperature of 58-60 C, the bath temperature was allowed to drop to
550 C.
during the course of 5 minutes The reaction mixture was diluted with
20 parts of diethyl ether, the polyvinyl acetal was precipitated by
the addition of a mixture of diethyl ether and petroleum ether, and
freed of hydroquinone and acetic acid essentially as described in
Example I, Section B, except that acetone was used as the solvent in
place of methanol There was obtained 82 parts of acetone solution
having a solids content of 27 % This polymer was a polyvinyl acetal
containing, besides intralinear -CHCHOH groups and gcetoxy groups,
acetal groups of the formula Ci-C Hf CH -C Hf0 a cho -co C= CH 2 CH 3
C Preparation of Printing Relief Images 65 To 37 parts of the above
acetone solution of the polyvinyl acetal, there was added 0 1 part of
benzoin methyl ether and 0 001 part of hydroquinone and the resulting
solution was cast on glass plates Removal of the acetone at 70 room
temperature in subdued light gave a clear, transparent film Exposure
of the film under a suitable negative and removal of the unexposed
material essentially as described in Example I, Section C, gave a
hard-scratch 75 resistant image of excellent sharpness.
Ex AMPLE XVII.
Preparation of p-Methacrylyloxybenzaldehyde Polyvinyl Acetal.
A mixture of 10 parts of medium viscosity 80 polyvinyl alcohol
(completely hydrolyzed polyvinyl acetate), 25 parts of
p-methacrylyloxybenzaldehyde (an excess over the quantity required to
acetalize all the hydroxyl groups), parts of glacial acetic acid, 7 5
parts of 85 trifluoroacetic acid and 0 1 part of hydroquinone was
stirred at 60 C for 10 minutes and then at 550 C for an additional
period of minutes The polyvinyl acetal was precipitated by the
addition of diethyl ether and the 90 hydroquinone and acetic acid were
removed essentially as described in Example I, Section B The acetone
solution ( 121 parts) had a solids content of 21 % Cast films
containing 1 % by weight of benzoin methyl ether and 95 0.01 % of
hydroquinone gave hard printing relief images of excellent sharpness
on exposure under a suitable line negative and removal of unexposed
material essentially as described in Example I, Section C Similar 100
results were obtained by substituting chloroform for the acetone, and
substituting a high viscosity polyvinyl alcohol (i e, a completely

hydrolyzed polyvinyl acetate having a viscosity of 45-55 centipoises)
for the medium 105 viscosity polyvinyl alcohol (which had a viscosity
of 20-25 centipoises.
EXAMPLE XVIII.
A Preparation of o-Methacrylyloxybenzaldehyde 110 To a solution of 122
parts of salicylaldehyde and 111 parts of anhydrous triethylamine in
350 parts of methylene chloride, there was added dropwise with
stirring a solution of 115 parts of methacrylyl chloride in 100 parts
of 115 methylene chloride, the temperature being maintained at 15-20 C
by means of external cooling The mixture was stirred at i 3 20-25 C
for an additional period of one hour after the addition of the acid
chloride was complete 300 parts of water containing parts of
concentrated hydrochloric acid was added, the organic layer was
separated and washed twice with 1 % hydrochloric acid.
After drying and adding 0 3 % part of hydroquinone, the solution was
concentrated and the residue was distilled There was obtained 162
parts of o-methacrylyloxybenzaldehyde, boiling range 105-110 C /1 mm.
Anal Calc'd for Cl H,1,O 3: C, 69 44; H, 5.30 Found: C, 69 32; H, 5
52.
B o-Methacryloxybenzaldelhyde Polyvinyl Acetal.
A mixture of 10 parts of 86-89 % hydrolyzed low viscosity polyvinyl
alcohol, 25 parts of a-methacrylyloxybenzaldehyde, 80 parts of glacial
acetic acid, 6 parts of trifluoroacetic acid and 0 1 part of
hydroquinone was stirred at 60-65 C for 15 minutes The reaction
mixture was diluted with 20 parts of diethyl ether and the polyvinyl
acetal was precipitated by the addition of a mixture of equal parts by
volume of ether and petroleum ether The polymer was freed of
hydroquinone and acetic acid essentially as described in Example I,
Section B except that acetone was used as the solvent in place of
methanol The acetone solution weighed 60 parts and had a solids
content of 37 %.
To the above acetone solution, there was added O 22 part of benzoin
methyl ether and 0 002 part of hydroquinone and the resulting solution
was cast on glass plates Removal of the acetone at room temperature in
subdued light gave a clear transparent film Exposure of the film under
a suitable negative and removal of the unexposed material essentially
as described in Example I, Section C gave a hard, scratch-resistant
image of excellent sharpness Similar images were obtained from the
polyvinyl acetal composition derived from o-methacrylyloxybenzaldehyde
and ( 1) 8689 % hydrolyzed medium viscosity polyvinyl alcohol, ( 2)
completely hydrolyzed medium viscosity polyvinyl alcohol and ( 3)
completely hydrolyzed high viscosity polyvinyl alcohol.
EXAMPLE XIX.

Thick films of the polyvinyl acetal of Example I were prepared by an
extrusion process as follows: To 392 parts of a methanol solution
containing 133 parts of the mnmethacrylamidobenzaldehyde polyvinyl
acetal, there was added 1 35 parts of benzoin methyl ether, 0 005 part
of hydroquinone, 160 parts of methanol and 100 parts of water The
resulting clear solution was poured slowly into 12,000 parts of
distilled water in which had been dissolved 30 parts of sodium
bicarbonate.
The polyvinyl acetal, ether and hydroquinone precipitated as a white
mass which was gathered into a lump and kneaded to work out excess
water and methanol The mixture at this stage was a coherent, opaque
white mass which contained approximately 37 % by weight of solvent
This dough was fed through a screw extruder with the barrel, head and
die temperatures at 35-405 C A beading die was 70 used Large amounts
of water were squeezed out during the first passage through the die
and the extruded material was recycled, after which it emerged as a
transparent amber cylindrical filament about -8 inch in diameter 75
The water content was approximately 20%, by weight At this point, the
beading die was replaced by a film die which included a screen pack
filter consisting of nvo 100 mesh screens between two 50 mesh screens
The film 80 die, about 3 inches in width, was set with lips 0.034 "
apart The transparent bead was passed into the extruder again, this
time passing through the film die The film of polyvinyl acetal and
initiator obtained was clear and flat 85 if a slight tension was kept
on the film as it left the die lips The thickness of the extruded film
was 0 035 to 0 050 inch depending on the exact amount of tension used
and the width, about 3 inches Residual solvent was removed 90 by
festooning the extruded film and drying in a current of air.
Such extruded films were laminated to cold rolled steel base sheets 0
015 " thick by a hot pressing operation The steel sheets were pre 95
pared for this use by cleaning, spraying on a zinc chromate-pigmented
polyvinyl butyral wash primer (as described in Plastic (March, 1953),
pages 86-87), drying, and applying a thin anchor layer of the
mn-methacrylamido 100 benzaldehyde polyvinyl acetal from an alcoholic
solution This solution comprised 10 parts of the polymeric acetal, 0
03 part of benzoin methyl ether, 65 parts of methanol and 25 parts of
n-butanol After the anchor 105 layer had dried thoroughly, the
extruded film was simultaneously laminated to the base and the surface
press-polished by pressing between polished plates at 100-1205 C for
one minute at 300 lbs per square inch The film 110 was cooled under
pressure.
Such a mi methacrylamidobenzaldehyde polyvinyl acetal layer on a steel
base plate was exposed in contact with a special negative containing
lines of varying width, double rules, 115 lines meeting at acute

angles, dots of various sizes and reverse print areas Exposure time
was 20 minutes and the surface of the transparency was placed at a
distance of 8 to 10 inches from a bank of sixteen 30-watt 120
fluorescent lamps which have a phosphor showing peak emission at
3500-3600 A The exposed plate was gently brushed in a tray of methanol
at 40-45 C to remove the unexposed areas The plate was then rinsed and
125 given a brief additional exposure to harden further the
addition-polymerized polyvinyl acetal printing relief image This plate
was locked on the cylinder of a rotary printing press and printed in
normal manner The test 13 Q 786,119 786,119 was discontinued after
upwards of 50,000 impressions had been made since little or no wear
was evident Reproduction of the detail present in the negative was
excellent.
Additional accelerated wear tests using an abrasive ink and paper on
plates made from this polyvinyl acetal printing relief showed that the
material is approximately equivalent to copper electrotypes in wear
resistance.
A halftone plate from a 150-line screen negative was prepared by
exposing and processing a photosensitive polyvinyl acetal layer
laminated to a metal base plate as described above The plate obtained
gave a printed image of excellent tonal gradation with dots 0 001 to 0
002 inch in diameter present in the extreme highlights.
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* GB786120 (A)
Description: GB786120 (A) ? 1957-11-13
Improvements in or relating to means for controlling the lateral positions
of movingwebs of material

Improvements in or relating to Means for Controlling the Lateral
Positions of Moving Webs of Material We, sill TS-SCHUCIRERTWERKE AHTI-
B-GESELLSCHAFT, a German Company, of 1 Berlin-Siemensstadt and
Erlangen, STermany, do hereby declare the invention, for which we pray
that a patent may be granted to us, and the method by which it is to
be performed, to be particularly described in and by the following
state- meut
This invention relates to means for controlling the lateral position
of a moving web of material.
When a web of material is caused to move in the direction of its
length the possibility exists of the edge of the web deviating from
its normal position transversdy of the direction of travel. As an
example of this, webs of paper which are wound on to rolls and which
travel through a rotary printing press or a cutting machine or a
similar device may move transversely due, for example, to
irregularities in the winding. In the ease of, for example, a
multi-colour rotary printing machine, the result of such a deviation
is that a displaeement of the successively applied inks of different
colours is prodnced, so that undesirable colour margins are formed. Tn
the case of cutting machines the consequence of such a lateral
deviation of the web of material would be that the sections cut off
would not be right-angled.
An object of the present invention is to reduce the disadvantages
outlined above bv controlling and regulating the position of the edges
of webs of material.
According to the invention there is prorided means for controlling the
lateral position of a moving web of material, for example a web of
paper moving in the direction of its length in a rotary printing
press, wherein one or more register marks is, or are, provided on a
rotatable element which is disposed on one side of the web near the
edge thereof and projects beyond such edge, there being arranged on
the other side of the web a light source which directs a beam of light
onto said edge and the exposed part of said element, and wherein a
photo-electric device is arranged to generate impulses when the mark
or marks or part thereof appear in the illuminated area, such impulses
being used to control an adjustment device which operates in
accordance with the nature of said impulses and serves to correct the
lateral position of the web should it deviate from the desired or
nominal position, the nature of the mark or marks and the proportion
of said element which is exposed dictating the nature of the impulses
in respect of their instants of occurrence relative to a reference
impulse or in respect either of their wave form or (in the case where

there are more than one mark on said element) their frequency.
For a better understanding of the invention and to show how the same
may be carried into effect, reference will now be made to the
accompanying drawing in which: Figs. 1 to 3 are plan views of three
different means for controlling the position of a moving web of
material.
Referring now to the drawing, in each of Figs. 1. to 3 a web 1 of
material moves in the direction of the arrow, that is to say in the
direction of the length of the web. One edge of the web 1 is shown in
its nominal position and is designated by 3 and it is supposed that
the web may move laterally so that the edge 3 lies between an
innermost extreme position 3a and an outermost position 3b.
In Fig. 1 a roller 2 is disposed with its axis in a plane horizontally
below that of the web 1 and perpendicular to the edge 3. The roller is
provided with a register mark 4 on its circumference, the mark taking
the form of a line which is inclined to the roller axis. The roller is
arranged to rotate in the direction indicated by the arrow and the
register mark on it is so arranged that when the edge of the web is in
its nominal position part of the mark, that is the end which leads
when the roller rotates, is concealed by the web of material. A light
source (not shown) is provided and it projects a beam on to the edge
of the material and on to part of the roller 2, thereby producing a
spot of light 5 on the material and the roller. A photoelectric device
(not shown) is so arranged near the web that it generates an impulse
when the register mark appears in the spot of light 5. It will be
readily appreciated that the instants at which the impulses commence
will depend upon the proportion of the register mark which is covered
by the web, the impulses commencing earlier when the edge of the web
is in the position 3a than when it is in the position 3b.
A reference impulse is also produced optimally, mechanically or by
other means and the impulse derived from the photoelectric device is
compared with this reference impulse so as to actuate an adjustment
member which corrects the position of the web accordingly. The
reference impulse can, for example, be produced by scanning a
reference mark 6 on the roller. The mark 6 may, however, be formed on
another member (not shown) coupled to the roller 6. If desired the
roller 2 may be driven directly by the web of material but it is
advantageous for it to be driven from a separate constant speed source
since it is then possible to detect lateral movement of the edges in a
manner independent of the speed of the web.
In Fig. 2 a roller 7 is arranged with its asis parallel to the edge 3
of the material.
The register marlr on the surface of the roller is here designated by
8, the spot of light from the light source by 9 and a reference mark

on the roller surface by 10, the latter being scanned bv a reference
scanning device 10cr In this case the register mark 8 is parallel to
the axis of the roller so that, as in the previous case, when the
roller is driven the instants at which the impulses occur relative to
the reference impulses depend upon the position of the edge of the
web. A differential impulse can be derived by comparison of the
impulses produced by the register mark and the reference mark and this
differential impulse is arranged to cause actuation of the member
which corrects the position of the web. As mentioned with reference to
Fig. 1, the reference mark can be arranged on a roller or a member
(not shown which is then coupled to the roller 7.
Fig. 3 shows a further constructional example in which a roller 2 is
arranged with its asis perpendicular to the edge 3 of t.he web. In
this ease, however, the surface of the roller is provided with a
plurality of register marks ila lib and lie all parallel with the axis
of the roller.
The register marks are of varying length, the marks 11(L being the
longest and the marks lie being the shortest. One end of each register
mark terminates at a circum- ferential line on the roller, this line
corresponding with the extreme position 'a of the edge of the web.
Thus when the edge of the web is at or near the extreme position 36b
at least part of each of the marks 11a, lib and lie will be visible so
that the frequency of the impulses generated by the photo-electric
device will be high. On the other hand, when the edge is at or near
the extreme position 3b only the marks 11a will be partly visible so
that the frequency of the impulses will be low. At the correct or
nominal position of the web an intermediate or reference frequenel-
will he obtained. It will be appreciated that more than three
different lengths of register marks can l)e employed if desired.
The factual frequencies derived from the photo-electric device will
also, of course, depend upon the numbers of each kind of rev sister
mark present. The marks are arranged symmetrically around the
circumference of the roller. When the edge of the web is in its
correct position, or within a region the width of which is equal to
the difference between the lengths ot the register marks 117, and lie,
the reference frequency is obtained and the adjustment member is not
actuated. Arhen, however, the edge moves outside this region the
frequency and the shape of the impulses alter and these alterations,
with the aid of a dividing network, lead to the actuation of the
adjustment member which corrects the position of the web. In this
ease, as in the case illustrated by Fio. 1 the roller may be driven br
the web itself or it may be independently driven at a constant speed.
Instead of musing register marks of different lengths, it is possible
for one or more register marks of, for example, triangular shape to be

so arranged on the periphery of tulle roller. preferably at equal
intelwals, that one side of each triangle extends parallel to the edge
of the weh of material. In the nominal position of the weh, half of
each triangle is concealed by the web from the photo-eleetrie device.
Consequenfly, there is then produced a sequence of impulses with a
predetermined wave form (i.e., amplitude and duration of indi-idual
impulses and the length of interval between successive impulses). The
wave form of the impulses is changed with alteration of the position
of the edge of the web so that the aforementioned predetermined wave
form acts as a standard for the deviation of the edge from its nominal
or pre-caleulated position. The evaluation of the impulses is
advantageously effected by a dividing network in combination with an
amplitude filter which sereens out the higher harmonics.
A magnetically operated electric impulse generator mav be used in
scanning the reference marks.
What we claim is
1. Means for controlling the lateral position of a moving web of
material, for example a web of paper moving in the direetion of its
length in a rotary printing press, wherein one or more register marks
is. or are, provided on a rotatable element which is disposed on one
side of the web near the edge thereof and projects beyond such edge,
there being arranged on the other side of the web a light source which
directs a beam of light onto said edge and the exposed part of said
element, and wherein a photo-electric. device is arranged to generate
impulses when the mark or marks or part thereof appear in the
illuminated area, such impulses being used to control an adjustment
device which operates in accordance with the nature of said impulses
and serves to correct the lateral position of the web should it
deviate from the desired or nominal position, the nature of the mark
or marks and the proportion of said element which is exposed dictating
the nature of the impulses in respect of their instants of occurrence
relative to a reference impulse or in respect either of their wave
form or (in the case where there are more than one mark on said
element) their frequency.
2. Means as claimed in Claim 1, wherein one of said register marks is
provided, being formed on the curved surface of a roller the asis of
rotation of which is generally perpendicular to the edge of the web of
material, such register mark being inclined to said axis and being
partly masked by an edge portion of the web so that the instants of
commencement of the impulses generated by the photo-electric device
depend upon the position of the web, the instants at which these
impulses commence when the web is in the desired position being a
standard for that position and deviations from the standard causing
actuation of said adjustment device.

3. Means as claimed in Claim 1, wherein one of said register marks is
provided, being formed on the curved surface of a roller the axis of
rotation of which is generally parallel to the edge of the web of
material, such register mark being generally parallel to said axis,
the arrangement being such that the roller is -partly masked bv an
edge portion of the web so that the instants of commencement of the
impulses generated by the photo-electric device depend upon the
position of the web, the instants at which these impulses commence
when the web is in the desired position being a standard for that
position and deviations from the standard causing actuation of said
adjustment device.
4. Means as claimed in any preceding claim, wherein the photo-electric
device is associated with means for generating reference impulses, the
arrangement being such that any differences between the instants of
occurrence of the reference impulses and the instants of occurrence of
the impulses generated by the photoelectric device create differential
impulses which actuate the adjustment device for the correction of the
lateral position of the web.
5. Means as claimed in Claim 1, wherein a plurality of said register
marks is provided, the marks being formed on the curved surface of a
roller the axis of rotation of which is generally perpendicular to the
edge of the web of material, such register marks being of differing
lengths and being arranged symmetrically around the circumference of
the roller, the arrangement being such that the number of register
marks which appear in the illuminated area depends upon the position
of the web of material so that the frequency of the impulses generated
by the photo-electric device also depends upon the position of the
web.
6. Means as claimed in Claim 1, wherein a plurality of said register
marks is provided, the marks being formed on the curved surface of a
roller the axis of rotation of which is generally perpendicular to the
edge of t.he web of material, such register marks having a
continuously variable width, for example of triangular form, and being
masked from the photoelectric device by the web of material to an
extent which depends upon the position of the web, so that the wave
form of the generated impulses when the web is in the desired position
can be employed as a standard for the deviation of the web from the
desired position.
7. Means as claimed in Claim 4, wherein the reference impulses are
derived from a separate scanning arrangement which is arranged to
co-operate with a reference mark formed on the roller or on a
rotatable member connected thereto.
8. Means as claimed in Claim 2 or 3 or any one of Claims 5 to 7,
wherein the roller is driven at constant speed

* GB786121 (A)
Description: GB786121 (A) ? 1957-11-13
Wattage controller system for electric heaters
PATENT SPECIFICATION
Invntar: CHARLES ROGER TURNER N 786 121 Date of Application and filing
Complete Specification Oct 3, 1955.
& 8 " 1 ' B No 28052/55.
Complete Specification Published Nov 13, 1957.
Index at Acceptance:-Classes 38 ( 4), A 2 B( 2: 3: 5); and 38 ( 5), Bl
S( 1 A: 5: 11).
International Classification: -HO 2 c, j.
Wattage Controller System for Electric Heaters We, PROCTOR ELECTRIC
COMPANY, a Corporation organized under the laws of the State of
Pennsylvania, United States of America, of Third and Hunting Park
Avenue, Philadelphia, Pennsylvania, United States of America, do
hereby declare the invention, for which we pray that a patent may be
granted to us, and the method by which it is to be performed, to be
particularly described in and by the following statement: -
The present invention relates to a wattage controller system for
controlling an electric heating load such as an electric range surface
heating unit It is a prime object of this invention to provide a
control that will effect rapid energization of a heating unit until
the desired operating temperature is reached, with subseqoent
senergization ito maintain the heating unit at that selected
temperature value.
A further object is to provide a system to bring a heating unit
rapidly to a selected temperature that will utilize an initial
instantaneous energization rate that is greater than that required to
maintain the heating unit at the maximum designed " heat " and
thereafter will cyclically energize and deenergize at the high
instantaneous energization rate to thereby maintain the heating unit

at its maximum " heat " after the unit has reached the predetermined
temperature value.
Another object is to provide a control system that utilizes a thermal
wattage controller to give the various average wattage inputs to the
heating unit, wherein one range of inputs is effected through a
wattage input in excess of the maximum the unit could normally
tolerate continuously, while utilizing, at another range of inputs, a
wattage considerably less than the maximum the unit could tolerate
continuously.
A further object is to provide a system that will permit the economy
of using a single coil heating unit.
The type of thermal wattage controller contemplated is c racterized in
that it provides lPicete 35 a particular wattage input or " heat " by
cyclically energizing and de-energizing the heating unit In systems of
this type, the thermal wattage controller should not cycle on and off
too frequently The maximum number of cycles in any period of time is
established at about 2 per minute This is not considered excessive
from the standpoint of contact life, radio interference, etc On the
other hand, in systems of this type, the length of the individual " on
" plus " off " intervals should not exceed a certain maximum This is
especially important in the lower range of inputs because excessive "
off" intervals are synonymous with large overshoot and undershoot and
inherent difficulty in maintaining correct average temperature at the
unit.
It is, therefore, another object to provide a controller that will
permit repid energization of a single coil heating unit and will have
favourable cycle lengths at the various heat levels.
Briefly, the present invention contemplates the energization of a
single coil electric range heating unit from a 3-wire electrical
supply through a controller which, by way of example, has the
following characteristics:Assuming the maximum continuous duty wattage
for the heating unit at 1250, " high " heat equivalent to 1250 watts
and " Medium High " heat equivalent to approximately 690 watts are
obtained by cyclically energising the heating unit at an instantaneous
load of 2400 watts; and the lower heats, namely:
"Medium ", "Low ", and " Simmer ", are obtained by cyclically
energizing the heating unit at an instantaneous load of 600 watts By
using the 2400 watts energization, the heating unit is rapidly brought
to its desired temperature level corresponding to the input selected.
Utilizing the 600 watts energization in the lower heats, provides
better cycle length characteristics and less inherent fluctuation due
to overshoot and undershoot than otherwise might be expected at the
lower wattage levels.
Referring now to the accompanying drawing:Figure 1 is a schematic

diagram of the control system for the heating unit; Figure 2 is a
detailed elevational view of a preferred form of the thermal switch,
Figure 3 is an exploded view of the thermomotive unit of the switch of
Figure 2; Figure 4 is a comparison chart of the cycle lengths at the
various " heats " when operating at various energization levels, and
Figure 5 shows in graphical form the contour of the cam used with the
thermal switch.
Figure 1 shows a heating unit 10 connected to a 3-wire electrical
supply line 11 through a controller 12 Heating unit 10 is of the rod
type generally used for electric range surface units and is made up of
one continuous resistance coil so that there are only two terminal
connections 14 and 15 Heating units of the rod type are well known in
the art, and it will suffice to say that such unit comprises a
metallic sheath 16, and inner coil resistance wire 17, held in place
by a heat conducting and electrically insulating ceramic material 18
The unit rests on a spider designated as 19 and is supported on the
top of an electric range through a reflector 20 and other
constructional elements The supply line 11 comprises line L, and L and
a neutral or common wire N In the discussion to follow the voltage
between L, and L, and N will be taken nominally as 118 volts, while
the voltage between L, and L.
will be taken nominally as 236 volts.
The controller 12 is shown to include a thermal switch 26 and a
double-throw singlepole switch 27, both insulatedly supported in or on
the controller 12 The thermal switch 26 is preferably of the type
disclosed and claimed in U S Patent No 2,623,137, and includes the
improvement thereon shown -in U S Patent Specification No 2,673,444
The thermal switch described in U S Patent Specification
No 2,623,137 includes a thermomotive means having a free end and a
fixed end and comprising two thermomotive members of thermomotively
dissimilar material disposed in substantially parallel spaced
relationship The more active of these themomotive members is a
bimetallic element having its low expansion side facing the less
active thermotive member, the latter being a heater strip These two
thermomotive members are mechanically connected together adjacent the
fixed end of the thermomotive means and at least at one point along
the length of the members Thermal insulating means is disposed between
the bimetallic element and the heater strip Electrical connections,
including contacts cyclically operable by the free end of the
thermomotive means, are provided for supplying energy to the heater
strip to heat the same rapidly during each cycle, the bimetalic
elements receiving heat from the heater strip through said thermal
insulating means The initial heating of the heater strip causes a
rapid thermomotive action in opposition to the thermomotive action of

the more active bimetallic element on heating Likewise the initial
cooling of the heating strip causes a rapid movement in 70 opposition
to the movement of the bimetallic element on cooling According to U S
Patent Specification No 2,673,444 the above mentioned thermal
insulating means is a flexible medium which provides accurate
mechanical 75 spacing between the bimetallic element and the heater
strip and a heat conductivity path which is substantially unchanged
over a substantial range of clamping pressure provided between the
bimetallic element and the heater strip 80 In addition the opposed
surfaces of said medium are characterised by a multiplicity of small
contact areas.
In Figure 1 the bimetallic element 30 and the heater strip 31 of the
thermal switch 26 85 are shown schematically, while the thermal
insulating medium between these two elements is omitted The bimetallic
element 30 is fixed at one end and is secured to the heater strip at
its free end An electrical contact 32 is car 90 ried on the free end
of bimetal 30 In Figure 1, the bimetallic element 30 is arranged to
flex upward, having its low expansion side up A cooperating contact 33
is carried on an adjustable blade 34 which is biased toward cam 95 36
and is positioned thereby through a cooperating projection 34 a on
blade 34 Cam 36 has an "off" position in which the projection 34 a
seats in a recess of the cam, and the cam has a progressively rising
surface in the 100 counter-clockwise direction as viewed in Figure 1.
Figures 2 and 3 shows the preferred form of the thermal switch 26 for
specific use with a heating unit of 2400 watts maximum ener 105
gization Between the bimetal 30 and the heater 31, as shown more
clearly in Figure 3, are disposed a rectangular strip of metallic
screening 40, an asbestos strip 41 and a mica strip 42 On the left
hand side of the heater 110 31 are disposed a mica strip 43, an
asbestos strip 44, and a brass shim 45 On the righthand side of
bimetal 30 are disposed a brass strip 46 and a brass clamping strip 47
The entire structure is fixedly supported on the 115 switch case 12
through a rivet 48 An insulator 49 separates the base of bimetal 30
and heating element 31 As may be seen in Figure 2, one electrical
connection to the thremal switch is connected to heater 31 through a
terminal 120 58, while the other electrical connection is connected to
resilient blade 34 which is insulated from heater 31 and from bimetal
30.
The bimetal used in this particular embodiment is of the kind known
under the Regis 125 tered Trade Mark " Morflex " and is 0 035 " thick;
and the heater is of 80 % nickel, 20 % chrome and has an approximate
resistance of 084 ohms The wire screening is of 30 x 30 mesh and of
015 " diameter stainless steel 130 786,121 786,121 3 wire, calendered
to 030 " thickness The brass strips 45, 46 and 47 are each 010 " thick

5711 5715.output

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