5766 5770.output

* GB786174 (A)
Description: GB786174 (A) ? 1957-11-13
Improvements in or relating to chemical nickel plating process
Description of GB786174 (A)
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The EPO does not accept any responsibility for the accuracy of data
and information originating from other authorities than the EPO; in
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up-to-date or fit for specific purposes.
PATENT SPECIFICATION
Inventor: PAUL TALMEY Date of Application and filing Complete
Specification: Feb 28, 1955.
No 5857/55.
Complete Specification Published: Nov 13, 1957.
Index at acceptance:-Class 82 ( 2), F(WBIB: 2 J; 2 Z 6), F 4 (A; E; F;
G; J: K; W; X).
international Classification;-C 23 c.
COMPLETE SPECIFICATION
Improvements in or relating to Chemical Nickel Plating Process We,
GENERAL AMERICAN TRANSPORTATION COR Po RAT Io N, a corporation
organised under the laws of the State of New York, United States of
America, of 135 South La Salle Street, City of Chicago, State of
Illinois, 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 improved processes of chemical nickel
plating of catalytic materials employing baths of the nickel
cation-hypophosphite anion, type, and more particularly to continuous
processes of chemical nickel plating.
The chemical nickel plating of a catalytic material employing an

aqueous bath of the nickel cation-hypophosphite anion type is based
upon the catalytic reduction of nickel cations to metallic nickel and
the corresponding oxidation of hypophosphite anions to phosphite
anions with the evolution of hydrogen gas at the catalytic surface The
reactions take place when the body of catalytic material is immersed
in the plating bath, and the exterior surface of the body of catalytic
material is coated with nickel The following elements are catalytic
for the oxidation of hypophosphite anions and thus may be directly
nickel plated: iron, cobalt, nickel, ruthenium, rhodiumi palladium,
osmium, iridium and platinum The following elements are examples of
materials which may be nickel plated by virtue of the initial
displacement deposition of nickel thereon, either directly or through
a galvanic effect: copper, silver, gold, beryllium, germanium,
aluminium, carbon, vanadium, molybdenum, tungsten, chromium,
seleniuml, titanium and uranium The following elements are examples of
non-catalytic materials which may not be nickel plated,:
bismuth, cachniumi, tin, lead and zinc The activity of the catalytic
materials varies considerably; and the following elements are
particularly good catalysts, in the chemical nickel plating bath:
iron, cobalt, nickel and pallat Price 3 s 6 d l diumi The chemical
nickel plating process is autocatalytic since both the original
surface of the body being plated and the nickel metal 50 that is
deposited on the surface thereof are catalytic.
In the continuous nickel plating system disclosed in copending
application No 19063/ 53 (Serial No' 785,693), periodic or' con 55
tinuous regeneration of the plating bath is effected by the
corresponding additions thereto of appropriate ingredients; for the
purpose of maintaining substantially constant the coinposition of the
plating bath The regeneration 60 of the plating solution in the
reservoir consistsi essentially of adding thereto appropriate amounts
of soluble nickel-containing and hypophosphite-containing reagents, as
well as an alkali for p H control 65 In the continuous plating system,
plating baths such as disclosed in our' copending application No
36334/53 (Serial No 785,696), areexpressly recommended, since they
exhibit an exceefdingly fast plating rate, and have an 70 exceedingly
long life because they acommodate the build-up of phosphite anions
therein to' a concentration above 1 0 mole/ litre, without the
precipitation of nickel phosphite and mixed basic salts 75 Also for
the purpose of increasing the stability of such a plating bath, it is
highly advantageous to add thereto a stabilizing additive, as
disclosed in our eopending applications No 31365/53 and 22974/56
(Serial 80 Nos 785,694 and 786,175).
In carrying out the continuous nickel plating process described in
coplending application 19063/53 (Serial No 785,693) the regeneration

of the relatively cool portion of 85 the aqueous plating solution in
the reservoir may be ekced either periodically or continuously during
the time interval that the body of catalytic material is being plated
in.
the hot portion of the plating solution in the 90 plating chamber, as
previously noted, whereby the additions of the nickel salt (such as
nickel chloride, nickel sulphate and nickel acetate) bring about the
introduction of the corres-
786,174 2 786,174 ponding foreign anions into the aqueous solution,
with the consequent build-up thereof through the successive cycles of
regeneration to a point where the concentration of the foreign anions
in the aqueous solution is excessive More particularly, the
concentration of the foreign anions in the aqueous plating solution is
excessive in the sense that the plating rate of the bath in the
plating chamber is s Iowed-down considerably; and mloreover, these
foreign anions, in excessive concentration, serve as crystal nuclei
for the precipitation of nickel salts, resulting in plating bath
instability.
Specifically, by way of illustration, it has been discovered that the
plating rate of a plating bath such as mentioned in copending
application No 36334/53 (Serial No 785,696) decreases linearly with
the concentration of Nael therein resulting from the employment of
nickel chloride in the regeneration thereof.
More particularly, the rate of decrease of the plating rate of the
plating bath with the increase in the concentration of Na Gl is:
( O 00053 grms/min,/cni P)/(moles Na Cl/litre) In ether words, if the
sodium chloride concentration, is raised froml zero to 6 0 males/
litre in the plating bath, the plating rate becomes less than half of
its original value.
Moreover, another phenomenon has been.
discovered in, this connection that is sometimes undesirable, i e, the
hardness of the nickel deposit upon the body of catalytic material
increases with the chloride concentration in the plating bath.
Accordingly, it is a general object of the present invention to
provide an improved process of chemical nickel plating of bodies
formed of catalytic material, employing a continuous chemical nickel
plating operation involving plating bath regeneration, wherein the
build-up of foreign anions as a consequence of the introduction of the
soluble nickel salt into the plating bath is not excessive as the
regeneration of the plating bath proceds.
Another object of the invention is to provide an improved process of
chemical nickel plating of the character noted, wherein the plating
bath regeneration is at least partially effected by the utilization of
nickel hypephosphite, whereby there is no foreign anion, of this

soluble nickel salt introduced into the plating bath.
A further object of the invention is to provide an improved nickel
plating process of the character described, wherein the plating bath
regeneration proceeds without the build-up therein of foreign anions,
such as, the chloride, the sulphate and the acetate.
These and other objects and advantages of the invention pertain, to
the particular arrangement of the steps of the process, as will be
understood from the foregoing and following description 65
The present invention provides a process of chemically plating with
nickel a solid body of catalytic material, which comprises contacting
said body throughout a time interval with an aqueous bath containing
nickel ions and hypo 70 phosphite ions, and regenerating said bath
during said time interval by adding thereto appropriate amounts of a
soluble alkali, nickel hypophosphite and another soluble hypophosphite
comprising hypophosphorous acid and/ 75 or an alkaline hypophosphite
(the term "alkaline hypophosphite" means herein a hypophosphite which
is an alkali metal or an alkaline earth metal hypophosphite), thereby
to minimize the introduction of extraneous ions into 80 said bath and
the consequent build-up of undesirable salts therein, incident to the
regeneration thereof.
In accordance with the process of the present invention, the article
or body to be 85 nickel plated, is prepared by mechanically cleaning,
degreasing and light pickling substantially in accordance with known
standard practices in the art For example, in the nickel plating of a
steel object, it is customary mech 90 anically to cleans the rust and
mill scale from the object, to degrease the object, and then lightly
to pickle the object in a suitable acid, such as hydrochloric acid The
article is then immersed in the plating bath provided in the 95
plating chamber of the continuous system described in copending
application, No 19063/ 53 (Serial No 785,693); whereupon almost
immediately hydrogen bubbles are formed on the catalytic surface of
the steel object and 100 escape in a steady stream from the plating
bath, while the surface of the steel object is slowly coated with
metallic nickel (containing some phosphorus) The reactions are
continued until the required thickness of the 105 nickel coating has
been deposited upon the surface of the steel object; whereupon the
steel object is removed from the plating bath in the plating chamber
of the continuous system, and is rinsed off with water so that 110 it
is ready for use.
In the formation of the plating solution in accordance with the
present invention, the soluble nickel salt that is employed is
selected from the group consisting of nickel chloride, 115 nickel
sulphate, nickel acetate and nickel hypophosphite, the other
hypophosphite that is employed is selected from the group, consisting

of hypophosphorous acid, sodium hypophosphite, potassium hypophosphite
and calcium 120 hypophosphite, the organic additives and appropriate
stabilizing cations are then introduced into the aqueous plating bath,
and the p-H thereof is appronriately adjusted employing Na OH and Na
CI Thereafter and during 125 the time interval that the body is being
nickel plated the plating bath is regenerated, as pre786,174 viously
described, employing nickel hypophosphite, another hypophosphite
(ordinarily an, alkaline hypophosphite, such as sodium hypophosphite)
and preferably a weak alkali, such as, sodium bicarbonate or a dilute
aqueous solution of caustic soda, for pl H control The reagents may be
added continuously or periodically during said time interval, and
preferably, to' a cool portion of the solution, such as that in the
reservoir of the system in copending application 19063/53 In, one
embodimnent of the present invention the absolute concentration of
hypophosphite in the bath expressed in moles/litre is within the range
0 15 to 1 20 The plating bath is generally maintained at a p H of 4 5
to) 9 5, preferably 4.5 to 7 0.
The process of plating may be further facilitated by the addition to
the plating solution of an agent in an amount at least sufficient to'
complex 100 % of the nickel ions therein and comprising a saturated
aliphatic hydroxy-carboxylic acid and/or a salt thereof and an
additive exalting the normal plating rate theof and comprising a
simple short chain saturated aliphatic dicarboxylic acid and/or al
salt thereof or an aliphatic amino carboxaylic acid and/or salt
thereof It may be carried out by circulating the plating solution from
a reservoir to' a plating chamber and then back to said reservoir,
heating said solution to a relatively high temperature slightly below
the boiling point thereof, preferably to 2100 F, after withdrawal
thereof from said reservoir and before introduction thereof into, said
plating chamber, cooling said solution to a relatively low temperature
well below the boiling point thereof, preferably to F, after
withdrawal thereof from said plating chamber and before return thereof
to said reservoir, immersing said body in the hot portion of said
solution in said plating chamber toi effect nickel plating: on the
surface of said body, withdrawing said body from said hot portion of
said solution in said plating chamber after a time interval
corresponding to the thickness of the nickel plating on the surface of
said body that is desired, and regenerating said solution during said
time interval to) compensate for the ingredients of said solution that
are exhausted during said time interval in said hot portion of said
solution in said plating chamber, said regeneration of said solution
consisting essentially of adding to the cool portion of said solution
in said reservoir appropriate amounts of nickel hypophosphite and
another soluble hypophosphite and a soluble alkali, said other

hypophosphite being selected from the group consisting of
hypophosphorous acid and alkaline hypophosphites, thereby toa minimize
the introduction of extraneous ions into' said bath and the consequent
build-up' of undesirable salts; therein incident to the regeneration
thereof.
In the regeneration of the plating solution, the depletion of the
nickel cations is compensated for by the addition of the nickel
hypophosphite, and the depletion of the hypophosphite is compensated
for by the additions of the nickel hypiophosphite and the other
hypophosphite, it being necessary to add both the nickel hypophosphite
and the other hypophosphite to the plating solution to' maintain the
desired ratio, between the nickel cations and the hypophosphite anions
in the range O 25 to 1 60 The addition of the alkali to' the plating
solution in the regeneration thereof is necessary since the p H of the
plating solution is automatically reduced as the reactions therein
proceed, whereby the addition of the alkali mentioned maintains the p
H of the plating solution in the range 4 5 to 9 5, preferably 4 5 to 7
0.
In accordance with the present process, the initial concentration of
sodium chloride prcsent in the aqueous plating solution, when nickel
chloride is employed in the initial formation, thereof, is not
excessive, and the concentration of sodium chloride therein is not
built-up as a consequence of the regeneration thereof by virtue of the
utilization of nickel hypophosphite, thereby avoiding the build-up of
the foreign chloride anion, as previously explained.
In, order to' demonstrate the present process, a first plating test
was performed in the continuous plating system described in copending
application No 19063/53 (Serial No 785,693) in which there is a
continuous flow of plating solution, employing previously cleaned cold
rolled steel samples and a plating bath of the character described in
copending application No' 36334/53 and having the particular
composition indicated below:
PLATING BATH NO 1 Nickel chloride 0 0675 moles per Litre Sodium
hypophosphite 0 225, , Sodium succinate 0 06,, ,,, Malic acid 0 135,,.
Pb++ as stabilizing ion 3 0 ppm Ratio:
Ni++/hypor 0 3 Initial p 1 H adjusted with Na OH 5 57 In this first
continuous plating test, it was assumed that the hy pophosphite
utilization was 0.3 for purposes of plating bath regeneration, and in
this connection hypophosphite utilization may be defined as the ratio
between the number of moles of nickel deposited in the plating
operation and the number of moles of hypophosphite consumed in the
plating operation h I other words, in this continuous system in order
to plate 3 moles of nickel upon the steel bodies 10 moles of
hypopihosphite are oxidized to' phosphite, which, of course, indicates

that in the regeneration of the plating bath, it is necessary to add
thereto 786,174 somewhat in excess of three times as many moles of
hypophosphite as moles of nickel.
This first continuous plating test was conducted through 11 cycles,
the temperature of the plating bath in the plating chamber being C,
with plating bath regeneration at the conclusion of each cycle
(employing nickel hypophosphite and sodium hypophosphite-to' supply
the required nickel cations and hypophosphite anions and to maintain
the desired ratio therebeeveen, and employing caustic soda to maintain
the p H within the desired range).
The results of this first continuous plating test were as follows:
Cycle No.
Initial p H Final p H Time of plating (min) Sample area cm 2 5.57 5 52
5 60 5 60 5 55 4.92 5 20 5 22 5 28 5 24 112 116 106 122 97 97 97 97 97
Wt gain, gms.
5.01 5 38 4 91 4.92 5 74 Rate Rx 10 Soln flow rate cc/min.
Cycle No.
Initial p H 4.62 4 78 4 86 5 08 4 85 51 49 50 57 47 5.52 11 5.52 5 50
5 52 5 51 5 51 Final p H Time of plating (min) 5.33 5 32 5 35 5 41 106
104 101 111 108 81.5 81 5 81.5 81 5 81 5 98 5 Wt gain, gms.
Rate R x 104 Solu flow rate cc/min.
4.57 4 43 4 24 4 63 4 55 5 77 5.29 5 20 5 15 5 12 5 16 5 27 54 55 50
51 53 51 A second plating test was performezd in the continuous
plating system described in copending application 19063/53 in which
there is a continuous flow of plating solution employing previously
cleaned cold rolled steel samples and a plating bath of the character
described in copending application No 36334/ 54 (Serial No 785,696)
and having the par 45 ticular comrposition indicated below:
is Sample area cm 2 5.40 5 37 111 86,114 PLATING BATH NO 2 Nickel
chloride 0 0675 moles/Litre Sodiumi hypophosphite 0 225,, Aminoacetic
acid 0 0675,, Malic acid 0 2025,, Pb++ as stabilizing ion 3 0 ppm
Ratio:
Ni++/hypo 0 3 Initial pi H adjusted with Na OH 6 52 In this second
continuous plating test, it was assumed that the hypophosphite
utilization was 0 3 for purposes of plating bath reCycle No.
generation, as previously explained This second continuous plating,
test was conducted through 11 cycles, the temperature of the plating
bath in the plating chamber being C, with plating bath regeneration at
the conclusionl of each cycle (employing nickel hypophosphite and
sodium hypophosphite to' supply the required nickel cations and
hypophosphite anions and to maintain the desired ratio therebetween,
and employing caustic soda to maintain the p H within the' desired
range).
The results of this second continuous plating test were as follows:

Initial p H Final p H Time of plating (min) Sample area, cm 2 6.52
5.51 6.51 6.53 6.51 6 49 5.87 5 82 5 95 5 95 106 118 97 97 97 97 97 Wt
gain, gms.
Rate R x 104 So In flow rate cc/min.
Cycle No.
5.71 6 00 6 96 6 65 5 34 4.92 5 83 5 98 5 82 5 68 48 54 48 48 59
Initial p H Final p H Time of plating, (min) Sample area, cm 2 6.50 6
51 6.50 6 48 6 48 6 48 6.09 6 28 6 28 6 29 6 20 6 30 127 119 136 111
81.5 81 5 81 5 81 5 81 5 98 5 Wt gain, gms.
Rate R x 104 6.01 5 72 6 02 6 18 5.81 5.90 5 91 6.37 6 60 5.62 5 80 6
04 Soln flow rate cc/min.
48 49 42 42 51 A third continuous plating test was performed in the
continuous plating system de, scribed in copending application
19063/53 in which there is a continuous flow of plating solution,
employing previously cleaned cold rolled steel samples and a plating
bath of the 55 character described in copending application No
36334/53 (Serial No 785,696) and having the particular composition
indicated below:
11 PLATING BATH NO 3 Nickel hypop'nosphite 0 0675 moles/Litre
Sodiumhypophcsphite 0 09 Arninoacetic acid 0 0675,, Malic acid 0 135
Pb++ as stabilizing ion 3 0 ppm Ratio:
Ni++/hypo O 3 Initial p H adjusted with Na OH 6 5 In this third
continuous plating test, it was assumed that the hypophosphite
utilization was 0 33 for purposes of plating bath regenCycle No.
Initial p H Final p H Time of plating, (min) Sample area, cm 2 Wt
gain, gms.
Rate R x 104 So In flow rate cc/min.
Loss of Nickel Ni++ moles/litre 6.51 5.68 4.67 4.88 0.0151 eration, as
previously explained This third continuous plating test was conducted
through 8 cycles, the temperature of the plating bath in the plating
chamber being 100 C, with plating bath regeneration at the conclusion
of each cycle (employing nickel hypophosphite and sodium hypophosphite
to supply the required nickel cations and hypophosphite anions and to
maintain the desired ratio therebetwen, and employing caustic soda to
maintain the p H within the desired range).
The results of this third continuous plating test were as follows:
6.61 5.82 102 5.26 5.33 0.0292 6.58 6.09 5.17 5.33 0.0444 6.60 6.00
103 5.29 5.29 0.0585 Cycle No 5 6 7 8 Initial p H 6 48 6 51 6 50 6 55
Final p H 6 01 6 06 6 12 6 22 Time of plating, (min) 101 106 120 107
Sample area, cm 2 97 97 97 98 7 Wt gain, gins 5 27 5 34 6 24 5 73 Rate
Rx 104 5 39 5 20 5 36 5 42 Soun flow rate cc/min 57 54 47 53 Loss of
Nickel Ni++ 0 0726 0 0868 0 1035 0 1187 moles/litre In the foregoing
continuous plating tests, the nickel deposits upon the cold rolled
steel samples were homogeneous, smooth and bright, the plating rates

indicated correspond to rates in excess of 1 5 mils ( O 0015 inch) per
hour, and the plating baths were totally devoid.
of turbidity or black precipitate Accordingly, these plating tests
clearly demonstrate the highly satisfactory commnercial character of
the present process.
In the foregoing continuous plating tests, it will be observed that in
the formation of plating baths Nos 1 and 2, the nickel salt employed
was nickel chloride; whereas in the formation of plating bath No 3,
the nickel salt employed was nickel hypophosphite On 786,174 786,174
the other hand, in the regeneration of the plating baths between
cycles in each of the continuous plating tests, the nickel salt em;
ployed was nickel hypophosphite Accordingly, it becomes substantially
immaterial whether the plating bath is initially formed utilizing as
the nickel salt, nickel chloride, nickel sulphate, nickel acetate or
nickel hypephosphite, since the introduction of the foreign anions
thereinto is not excessive, as long as the regeneration of the plating
bath between cycles is carried out employing nickel hypophosphite.
In the foregoing discussion and tests the plating rate may be defined:
R = weight gain in the nickel plating in gram/cm 12/minu te of the
plated surface of the test sample, or expressed simply:
R = gmi/cm/n/min In, view of the foregoing, it is apparent that there
has been provided an improved process of chemical nickel plating of
catalytic bodies that is particularly well-suited to the production of
commercial coatings, since the process is continuous', and the plating
bath exhibits an exceedingly fast plating rate and has an exceedingly
long life.
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* GB786175 (A)
Description: GB786175 (A) ? 1957-11-13
Improvements in or relating to chemical nickel plating bath and process

786,175 Date of Application and filing Complete Specification: Nov 12,
1953.
No 229741 f 56.
Application made in United States of America on June 3, 1953.
-r, /(Divided out of No 785,694) Complete Specification Published:
Nov 13, 1957.
Index at acceptance:-Class 82 ( 2), F( 1 81 B:2 U:2 Z 6), F 4
(A:E:FW::J:K:W:X).
International Classification:-C 23 c.
Improvements in or relating to Chemical Nickel Plating Bath and
Process We, GENERAL AMERICAN TRANSPORTATION CORPORATION, a corporation
organised under the laws of the State of New York, United States of
America, of 135 South La Salle Street, Chicago, Illinois, 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 improved processes of chemical nickel
plating of catalytic materials employing baths of the nickel
cation-hypophosphite anion type containing stabilizing agents.
The chemical nickel plating of a catalytic material employing an
aqueous bath of the nickel cation-hypophosphite anion type is based
upon the catalytic reduction of nickel cations to metallic nickel and
the corresponding oxidation of hypophosphite anions to phosphite
anions with the evolution of hydrogen gas at the catalytic surface The
reactions take place when the body of catalytic material is immersed
in the plating bath, and the exterior surface of the body of catalytic
material is coated with nickel The following elements are catalytic
for the oxidation of hypophosphite and thus may be directly
nickel-plated, iron, cobalt, nickel, ruthenium rhodium, palladium,

osmium, iridium and platinum The following elements are examples of
materials which may be nickel-plated by virtue of the initial
displacement deposition of nickel thereon either directly or through a
galvanic effect:
copper, silver, gold, beryllium, germanium, aluminium, carbon,
vanadium, molybdenum, tungsten, chromium, selenium, titanium and
uranium The following elements are examples of non-catalytic materials
which may not be nickel-plated: bismuth, cadmium, tin, lead and zinc
The activity of the catalytic materials varies considerably; and the
following elements are particularly good lPrice 3/61 catalysts in the
chemical nickel plating bath:
iron, cobalt, nickel and palladium The chemical nickel plating process
is autocatalytic since both the original surface of the body being
plated and the nickel metal that 50 is deposited on the surface
thereof are both catalytic, and the reduction of the nickel cations to
metallic nickel in the plating bath proceeds until all of the nickel
cations have been reduced to metallic nickel, in the pre 55 sence of
an excess of hypophosphite anions, or until all of the hypophosphite
anions have been oxidized to phosphite anions, in the presence of an
excess of nickel cations.
Actually the reactions are slowed-down 60 rather rapidly as time
proceeds because the anions, as contrasted with the cations, of the
nickel salt that is dissolved in the plating bath combine with the
hydrogen cations to form an acid, which, in turn, lowers the p H 65 of
the bath, and the reducing power of the hypophosphite anions is
decreased as the p H value of the bath decreases Moreover, there is a
tendency for the early formation in the plating bath of a "black
precipitate" that 70 results from a random chemical reduction of the
nickel cations Of course, this formation of the black precipitate
comprises a decomposition of the plating bath and is particularly
objectionable in that it causes 75 the nickel deposit to be coarse,
rough and frequently porous.
For the dual purposes of increasing the stability of the plating bath
(preventing the formation of the black precipitate men 80 tioned), and
of increasing the normal plating rate of the bath, various baths of
the present type have been suggested employing different additives or
agents that serve either as buffers or as exaltants A chemical nickel
85 plating bath of the nickel cation-hypophosphite anion type has been
proposed that contains as an additive a buffer in the form of a
soluble salt of an organic acid, particularly sodium acetate A
chemical nickel plating 90 ? e 25 p -:'I r 4NS I 786,175 bath of the
nickel cation-hypophosphite anion type Ris disclosed in our copending
Application No 17206/53 (Specification
Serial No 761,062), that contains as an additive an exaltant in the

form of a soluble salt of a simple short-chain saturated aliphatic
dicarboxylic acid, and specifically sodium succinate.
In carrying out the chemical nickel plating process, particularly in a
continuous system such as disclosed in our copending Application No
19063/53 (Serial No.
785,693), it has been discovered that an initially stable plating bath
becomes unstable after some use, and notwithstanding the content of
the buffer, or the exaltant, or both, whereby the plating bath
decomposes with the formation of the previously mentioned black
precipitate It is believed that the formation of the black precipitate
(the first visible manifestation in the plating bath of random
reduction of the nickel cations) starts at the surfaces of suspensoids
(solid particles of dust, microcrystalline precipitate of ferric
hypophosphite, nickel phosphite, etc), present in the plating bath,
and the presence of these suspensoids in the plating bath is evidenced
by the observation of Tyndall beams when a shaft of light is passed
through the clear filtered plating bath, even when freshly prepared.
The present invention is predicated upon the discovery that such
plating baths may be stabilized to a high degree, without material
depression of the plating rates thereof, by the further addition
thereto of a trace amount of certain water-soluble additives of
dipolar molecular character.
In accordance with the present invention there is provided a nickel
plating bath which comprises an aqueous solution containing nickel
ions, hypophosphite ions and an amount of a stabilizing additive so as
not substantially to reduce the plating rate of the bath and so as to
inhibit random decomposition of the bath, said stabilizing additive
comprising a long chain aliphatic compound containing at least 6
carbon atoms in the aliphatic chain and being capable of forming an
oriented hydrophobic film on the material to be plated.
In the plating bath ofr the present invention the cation of the
dipolar molecule is readily dissociated and the anion of the dipolar
molecule forms with the metallic element of any suspensoids which may
be present a water-insoluble product that is hydrophobic or water
repellent.
The presence of these suspensoids is undesirable and the purpose of
the additive is to form hydrophobic films upon suspensoids that may be
in the plating bath.
The additive is capable of forming an oriented hydrophobic film on the
surface of the material to be plated and since any additive which
remains after the suspensoids have been coated will attach itself to
the material to be plated, the amount of the additive present should
be limited so as not to have an inhibiting effect on the surface of
the object 70 being plated.

In accordance with the invention only a trace amount of the additive
is placed in the aqueous solution in forming the bath Preferably, the
long chain aliphatic compound 75 comprising the stabilizing additive
of this invention contains not more than 18 carbon atoms, i e, 6-18
carbon atomns, in the aliphatic chain In general, the additive
compound is selected from the class consisting of ali 80 phatic
carboxylic acids and alkali metal salts and sulphates and sulphonates
thereof unsaturated aliphatic amines and salts thereof, such as an
amine acetate and unsaturated aliphatic long chain alcohols In large
quan 85 tities the aliphatic radical present in the bath is a
catalytic poison, and will considerably reduce the plating rate or
stop plating altogether However at the proper concentration, the
aliphatic radical prevents random 90 decomposition of the plating bath
and the formation of the black precipitate mentioned.
the proper quantity of aliphatic radical in the plating bath to
achieve stability being not greater than 100 parts per 1,000,000 95
parts by weight of the plating bath, preferablv in the range 5 to 100
parts per 1,000,000 parts of the plating bath by weight.
In accordance with the plating process of the present invention, the
article to be nickel 100 plated and formed of a catalytic material is
prepared by mechanically cleaning, degreasing and light pickling,
substantially in accordance with standard practices in electroplating
processes 105 With respect to the composition of the bath, it
comprises an aqueous solution containing nickel cations, hypophosphite
anions, a buffer or exaltant, and a stabilizing agent.
For example, the nickel cations may be 110 derived from nickel
chloride, and the hypophosphite anions may be derived from sodium,
potassium, lithium, calcium mannesium, strontium or barium,
hypophosphites, or various combinations thereof 115 Specifically a
suitable bath may be formed in an exceedingly simple manner by
dissolving in a hydrochloric acid-water solution nickel chloride and
sodium hypophosphite, and then the buffer or exaltant and the 120
stabilizing agent are added thereto, as explained more fully
hereinafter The desired p H of the bath is established by the eventual
introduction thereinto of additional hvdrochloric acid and is
appropriately adjusted 125 by the addition thereto of a weak alkali,
preferably sodium bicarbonate.
The terms "cation" "anion", and "ion" as employed herein, except where
specifically noted, include the total quantity of the 130 786,175
corresponding elements that are present in the plating bath, i e, both
undissociated and dissociated material In other words, 100 %)
dissociation is assumed when the terms noted are used ir connection
with molar ratios and concentrations in the plating bath.
The stabilizing effects of the various organic compounds mentioned

were determined from a series of plating tests that were made
employing a "standard" test plating bath having a volume of 50 cc and
a temperature between 98 C and 100 'C Low carbon steel samples were
plated that had a surface area of 20 cm 2 and that had been
vapour-degreased, electro-cleaned, and pickled in a 10 % HCI solution
The standard test plating bath was produced from a solution containing
nickel as nickel hypophosphite ( 0 09 mole/litre), sodium
hypophosphite ( 0 045 mole/litre), sodium succinate ( 0.06
mole/litre), sodium chloride ( 0 18 mole /litre), and enough water to
make one litre, the peel having been adjusted to a value of 4.6 with
pure Hl, whereby the nickel cation/hypophosphite anion ratio was 0 4.
The stabilizing agents were then added to the standard test plating
bath by measuring the proper volume from stock solutions containing
1,000 ppm thereof, and the plating rates (R) were measured in gm/cm
2/min.
In these tests stability is indicated by the time in minutes that
elapsed before "black precipitate" was formed, and the appearance of
the nickel deposited upon the samples was ppm of sodium oleate Wt gain
gms p H begin p H end Sample Appear Time to black ppt min.
noted In describing the appearance of a 35 test sample, the following
symbols are employed: B= Semi-bright (satin), BB =Bright, VB = Very
bright, S= Smooth, SR= Slightly rough, R=Rough, D=Dull, and Sp=
Spotted 40 Two "blank" plating tests were first run employing only the
test samples in the standard test plating bath (without the addition
of any stabilizing agent), with the following results: 45 Duration of
test 10 min 60 min.
Weight gain, gms 0 0948 0 1903 Plating rate Rx 104 4 74 Sample
appearance B-S B-SR Time to black ppt None 20 mins 50 From the two
above blank plating tests, it is apparent that the standard test
plating bath is unstable since noticeable decomposition thereof takes
place within 20 minutes; and hereafter a plating bath is considered
"un 55 stable" if it decomposes within a time interval of 60 minutes.
Comparable plating tests were then made employing the standard test
plating bath containing as stabilizing agents the various 60 organic
compounds mentioned, the stabilizing agents being added to the baths
from stock solutions containing 1,000 ppm of the organic molecule.
In a series of these plating tests employ 65 ing the standard test
plating bath containing sodium oleate as the stabilizing agent, the
following results were obtained:Stability test-60 minutes 10 0 1334 0
1376 4 58 4 58 2 80 2 63 BB-S BB-S 10 0.1401 4.58 2.73 RB-S 0.1384
4.58 BB-S 0.1469 4.58 BB-S In a series of these plating tests employ
potassium oleate as the stabilizing agent, the ing the standard test
plating bath containing following results were obtained:ppm of
potassium oleate Weight gain, gms.

Plating rate Rxl O 4.
Sample appearance Time to black ppt.
p H begin p H end ppm potassium oleate Wt gain gins.
p H 1 begin p H end Sample Appear.
Time to black ppt min.
(a) Rate test-10 minutes 0 25 50 0.0596 0 0577 0 0542 2.98 2 89 2 71
BB-S BB-S BB-S none 4.59 4 59 4 59 3.98 4 02 4 07 (b) Stability
test-60 minutes None 10 0 1253 0 1379 4 58 4 58 2 780 2 65 BB-S BB-S
10 0.1382 4.58 2.66 RB-S 0.1392 4.58 2.67 BB-S 0.1483 4.58 2.62 BB-S
786,175 The foregoing plating tests employing the standard test
plating bath containing either sodium oleate or potassium oleate
establish that stabilization is achieved at 75 ppm.
A series of these plating tests were conducted employing the standard
test plating bath containing a high molecular weight iminodazoline
("Amine 0, manufactured by Alrose Chemical Co) as the stabilizine
agent "Amine 0 " is fundamentally l Phydro 10
xyethyl-2-heptadecenivl-imino'dazoline of approximately 880 purity and
in these plating tests the following results were obtained:(a) Rate
test-10 minates 0 0 0649 3 25 ppm of " Amine 0 " Weight gain, gms.
Plating rate Rxl O 4 Sample App.
Time to black ppt.
p H begin p H end Bath appear.
ppm of " Amine " 0 Weight gain, gms.
Sample App.
Time to black ppt.
p H begin p H end Bath app.
In view of the foregoing plating tests employing in the standard test
plating bath "Amine O " as the stabilizing agent, it will be observed
that the stabilizing range is 5 0 ppm and above, with acceptable rates
up to ppm.
A series of these plating tests were conducted employing the standard
test plating bath containing acetic acid salts of primary ppm of "
Armac T" Weight gain, gins.
Plating rate Rx 10.
Sample app Time to black ppt.
ppm of " Armac T" Weight gain, gms.
Sample app Time to black ppt.
1 5 0.0538 0 0573 2.69 2 87 sc 0.0566 2.83 none 4.59 4 59 4 59 4 59 20
3.93 4 08 4 04 4 05 clear, green (b) Stability tests-60 minutes 0 1 5
10 25 50 0.1341 0 1361 0 1292 0 1248 0 1137 0 0995 25 BB-SR BB-S BB-S
Sp-S Sp-S Sp-S 12 10 stable
4.61 4 61 4 61 4 61 4 61 4 61 2.52 2 66 2 88 3 00 3 31 3 58 clear,

green 30 fatty amines ("Armac T" manufactured by 40 Armour & Co, the
word "Armac" being a Registered Trade Mark) as the stabilizing agent
"Armac T" is fundamentally a tallow amineacetate consisting of 30 oq
hexadecylamineacetate, 25 % octadecylamineacetate and 45 %
octadecenylamineacetate and in these plating tests the following
results were obtained:(a) Rate test-10 minutes U 1 5 10 25 50 50
0.0649 0 0657 0 0291 0 0177 0 0008 0 0005 3.25 3 29 1 46 0 89 0 04 0
03 BB-S BB-S Sp-S Sp-S Sp-S Sp-S none 3.25 3 92 4 29 3 40 4 58 4 59 55
5.59 4 59 4 59 4 59 4 59 4 59 Clear green-Slightly turbid Turbid,
green-green(b) Stability tests-60 mintes 0 1 5 10 25 50 0.1286 0 1449
0 1345 0 0727 0 0140 0 0014 60 BB-S BB-S BB-S Sp-S Sp-S Sp-S 13 12
stable
4.61 4 61 4 61 4 16 4 61 4 61 2.71 2 52 2 69 3 79 4 41 4 54 clear,
green Turbid green 65 In view of the foregoing plating tests employing
in the standard test plating bath "Armac T" as the stabilizing agent,
it will be observed that the stabilizing range is 5 0 ppm and above,
with an optimum rate at ppm.
In a series of these plating tests employing the standard test plating
bath containing the isopropanol amide of oleic acid ("Emcol X-25 "
manufactured by Emulsol Corp) as 75 the stabilizing agent, the
following results were obtained: 786,175 ppm of " Emcol X-25 " Weight
gain, gns Plating rate Rxl O 4 s Sample app Time to black ppt p H
begin p H end Bath App (a) Rate test-10 minutes 0 10 0 0422 0 0436 2
11 2 18 ' BB-S BB-S 0.0444 2.22 none 458 4 58 4 58 4 58 413 4 13 4 12
4:14 clear, green ppm of " Emcol X-25 " Weight gain, gins Sample App.
Time to black ppt p H begin p H end Bath app (b) Stability tests-60
minutes 0 1 0.1286 0 1506 BB-S BB-R 13 20 4.61 4 61 2.71 2 41 10 25 50
0.1441 0 1432 0 1462 0 1453 BB-S 30 55 Stable
4.61 4 61 4 61 4 61 2.55 2 56 2 52 2 54 clear, green In view of the
foregoing plating tests employing in tthe standard test plating bath
-Emcol X-25 " as the stabilizing agent, it will be observed that the
stabilizing range is O.0 ppm and above.
Tche minimum amounts of the different ones of these organic
stabilizing agents that are required to achieve stabilization are a
function of nickel cation concentration in the plating baths, whereby
the minimum amount of the stabilizing agent that must be added thereto
must be disproportionately increased as the nickel cation
concentration in the plating bath is increased However, these minimum
amounts of the different organic stabilizing agents are otherwise
independent of the particular compositions of the plating baths with
reference to other constituents This is probably due to the fact that
they do not form complexes with such constituents as malic acid,
lactic acid and amino-acetic acid Thus these organic stabilizing
agents are very advantageous when used in proper amounts since they do

not decrease the plating rate of the plating baths over wide ranges
and they tend to increase substantially the brightness of the plated
bodies, and moreover they do not have any adverse action on the
adhesion of the nickel plating upon the base metal of the plated
bodies.
In carrying out the present process in a continuous plating operation,
it is recommended that trace quantities of the selected stabilizing
agent be fed periodically or continuously into the plating bath along
with the other regenerating chemicals (particularly the nickel cations
and the hypophosphite anions) so as to keep the level thereof
substantially constant and at that required, as previously explained
For example, the simplest and safest procedure lis to select la
stabilizing agent that is known to be active, and not objectionable
with respect to decreasing the plating rate over a relatively wide
range of concentration, and then to keep the level of concentration of
the stabilizing agent within the effective range by the required 65
addition thereof to the plating bath along with the other regenerating
ingredients, as noted above The temperature of the plating bath is
generally above 90 'C and the ph thereof is in the range 3 0 to 5 5 70
Amounts of said stabilizing additive are added during the regeneration
sufficient to maintain controlled trace amounts ithereof in the bath
throughout the time interval during which the catalytic material to be
plated 75 is contacted with the plating bath.
In the appended claims the term "catalytic material" means any
material which can be nickel-plated in an aqueous bath of the nickel
cation-hypophosphite anion type with the 80 evolution of hydrogen gas
at the catalytic surface, and includes a material comprising an
element which is catalytic for the oxidation of hypophosphite anions
as previously set forth herein, and materials comprising an 85 element
which may be nickel-plated by virtue of the initial displacement
deposition of nickel thereon either directly or through a galvanic
effect, as previously set forth herein.
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* GB786176 (A)

Description: GB786176 (A) ? 1957-11-13
Polyester films and their production
A high quality text as facsimile in your desired language may be available
amongst the following family members:
BE538815 (A) DE1095514 (B) FR1137334 (A) US2779684 (A)
BE538815 (A) DE1095514 (B) FR1137334 (A) US2779684 (A) less
Date of Application and filing Complete Specification: May 20, 1955
No.
1 P Application made in United States of America on June 8, 1954.
^ O g / Application made in United States of America on Feb17, 1955.
___ i <Complete Specification Published: Nov 13, 1957.
Inden eit aaoeptance:-Classes 2 ( 2)l, E( 2:612)9 and 1 IMI 1 E 0,
Inteiniationsia Classification -b 329 d, D 03 m.
Polyester Films and their Production We, E I Du PONT Ds E NEMOURS AND
COMPANY, a Corporation organised and existing under the laws of the
State of Delaware United States of America, located at Wilmington 98,
Delaware, United States of America, do hereby declare the invention
by which it is to be performed to be particularly described in and by
the following statement: -
This invention relates to self-supporting oriented polyester films of
improved dimensional stability and to such films having an adherent
substratum of a polymeric filmforming material and a water-permeable
colloid layer The invention also relates to light-insensitive products

obtainable by such processes, to a photographic film having at least
one water-permeable colloid silver halide emulsion layer disposed on
such polymer coated polyester film either directly or by means of a
water-permeable colloid anchor layer, and to the production of all the
said materials.
In United States Patent No 2,627,088, there is disclosed a process of
preparing photographic flim including casting or extruding into the
form of a self-supporting sheet of film, a molten highly polymeric
ester of a dicarboxylic acid and a dihydric alcohol, said ester being
capable of being formed into filaments which when cold drawn show by
characteristic X-ray patterns molecular orientation along the fibre
axis, coating at least one surface of the polyester film with an
aqueous dispersion of a copolymer containing at least 350, by weight
of vinylidene chloride, drying the coated film and biaxially orienting
the coated film by stretching it at an elevated temperature A
water-permeable colloid layer is then applied to the layer of
copolymer to serve as an anchor layer for a colloid silver halide
emulsion layer.
Photographic film produce in accordance with the process of the
aforesaid United States Patent has many useful properties Its
mechanical strength and flexibility are excellent and it has excellent
dimensional stability when exposed to temperatures below 90 WC.
Water-permeable colloid silver halide emul 50 sion layers have strong
adherence to the polymer-coated base film Such photographic film is
useful as X-ray film, portrait film, motion picture film and for
photographic purposes in general 55 Motion picture exhibitors are now
using projectors which operate at higher temperatures than formerly,
because of the use of larger viewing screens and three-dimensional
pictures The perforated photographic film 60 used in such projectors
is often raised to temperatures of 120 'C or higher, which causes a
slight shrinkage in the pitch from one perforation to the next which,
in turn, causes unsteadiness, chatter, vibrations and wobble 65 The
distance between perforations decreases so that the teeth on the
projection apparatus do not engage the perforations uniformly and
accurately Moreover, the shrinkage may result in buckling of the film
which causes 70 image distortion on the screen.
The present invention provides polyester films with improved
dimensional stability.
By the expression "polyester" is meant a highly polymeric ester of a
dicarboxylic acid 75 and a dihydric alcohol, the said ester being one
which is capable of being formed into filaments which when cold drawn
show by characteristic X-ray patterns molecular orientation along the
fibre axis By the ex 80 pression "dimensionally stable" is meant that
the film is substantially stable in dimensions under all normal

conditions of use and shows no significant shrinkage when exposed to a
temperature of 120 'C for five minutes under 85 conditions of no
tension By the term "biaxially oriented" is to be understood the
condition of a film which has been stretched in each of two directions
at right angles in either order or simultaneously, and the term 90
"biaxially orienting" refers to this stretching process.
69176 14685/55.
t.
7 $ 8 786,176 According to the present invention a process for the
production of a dimensionally stable polyester film comprises forming
a sheet of film from a molten polyester (as hereinbefore defined), and
particularly of a polyethylene terephthalate, biaxially orienting the
film by stretching it in two directions at right angles at elevated
temperature, heat-setting the film at a temperature from 150 'C to 210
'C under conditions such that no shrinkage occurs and modifying the
heat-set film by heating it to a temperature of 10 CC to 150 'C for a
period of 1 to 5 minutes while under a tension between 10 and 300 and
preferably between 10 and 25 pounds per square inch When the film is
to be used as a base for photographic purposes, the second heating
operation can be carried out either before or after the application of
a water-permeable colloid substratum for anchoring a water-permeable
colloid silver halide emulsion layer to the polyester film.
This second heat treatment, which is carried out at a temperature
above the temperatures normally used in drying aqueous water-permeable
colloid layers, relaxes the stresses in the biaxially-oriented film
and markedly improves its dimensional stability.
The amount of tension to be used for relaxing stresses in a particular
polyester film will depend primarily upon the temperature to which it
will be subjected in use In general, moreover, the tension will be
increased, between the limits given above in proportion to the
increase in the temperature of the heat treatment For example, in
order to produce a polyester film which does not shrink more than 0 2
' in dimensions when heated to 'C for five minutes, a tension of 175
pounds per square inch can be used at a temperature of 120 'C for a
period of 5 minutes, or a tension of 295 pounds per square inch can be
used at 1390 C for a period of 5 minutes.
In one method of carrying out the invention, a molten polyester, e g,
a polythylene terephthalate, is cast or extruded onto a suitable
smooth surface and stretched longitudinally and laterally, in either
order or simultaneously, at a temperature of 70 WC to 1200 C, heat-set
at a temperature between 'C and 210 'C at a tension such that
dimensions will be held constant, and then passed into a heating zone
where it is heated to a temperature between 110 'C and 150 'C.
for a period of 1 to 5 minutes under slight tension, whereby internal

stresses are relaxed.
The casting or extrusion of the polyester into the form of a film and
the stretching of the film can be carried out with any conventional
apparatus for this purpose An especially useful extrusion apparatus is
described in Specification No 772,148 and in Application Nos 2226155
and 25572/56 (Serial Nos.
779,645 and 779,646) An especially useful stretching apparatus is
disclosed in Specification No 746,386.
The polyester film may be composed of any polyester of a dicarboxylic
acid and a dihydric alcohol of the type described in United 70 States
Patent No 2,071,250 or may be composed of any of the high-melting
difficultly soluble, usually microcrystalline, cold-drawing linear,
highly polymerised esters of terephthalic acid and glycols of the
series HO 75 (CH 2)COH, where ni is an integer within the range of 2
to 10 described in United States Patent No 2,465,319.
The polyesters used in accordance with the present invention need not
consist solely of 80 glycol units since some of the glycols react to
form polyglycols and small percentages of units from such polyglycols
can be present.
For instance, when ethylene glycol is a reactant, the polyester may
contain from 1 to 85 ' or more of units from diethylene glycol (i.e
-CH CH OCHCH,O-units) Also when a mixture of glycols and polyglycols
is used.
e.g, ethylene glycol and diethylene glycol, the copolymers may contain
a substantial 90 proportion of oxyethvlene units.
If desired, the polyester film can be coated with a thin lay&r of an
adherent film-forming copolymer prior to the biaxial stretching step
or steps Suitable copolymers for this purpose 95 include ( 1) the
vinylidene chloride copolymers containing at least 35- by weight of
vinylidene chloride, e g, the poly(vinylidene chloride co acrylic or
methacrylic ester or nitrile co itaconic acid) compounds described in
100 United States Patent No 2,627,088, ( 2) the polyisocyanates and
polyisothiocyanates described in United States Patent No 2,698 242, (
3) a polyester of ethylene glycol, terephthalic acid and a third
component in the form of a 105 polyethylene glycol or a saturated
aliphatic dicarboxylic acid, soluble in trichloro-ethylene in
admixture with an organic polyisocyanate or polyisothiocyanate
described in United States Patent No 2,698,241 and ( 4) 110 the
polyesters described in United States Patent No 2,698,239 Such layers
will be applied of the heat set, heat-relaxed film is to be used for
the manufacture of photographic film In such case, it is desirable to
115 apply a thin layer of a water-permeable colloid, e g, gelatin or a
synthetic colloid or mixture of the two, from an aqueous solution or
dispersion and to dry the said layer at a temperature of 100 'C to 105

'C before the heat 120 relaxing operation.
The polyester film may contain a pigment or dye to colour it any
desired colour When the film is to be used as a photographic film base
for X-ray film, it may be tinted green 125 or blue The copolymer layer
may be similarly tinted and may contain an antistatic material
Antistatic layers and antibalation layers can be coated on the surface
of the film or on the copolymer layer 130 786,176 The invention is not
limited to the particular layer of adherent film-forming copolymers
described above (which are esssentially hydrophobic in character) as
other adherent copolymers can be used as an anchoring substratum for a
water-permeable colloid layer.
Additional water-permeable colloids having a protective colloid action
which can be used include water-soluble polyvinyl alcohol derivatives
in general, e g, partially hydrolyged polyvinyl acetates, and mixed
polyvinylchloride-acetates, hydrolysed interpolymers of vinyl acetate
with unsaturated compounds, for example, maleic anhydride and acrylic
acid esters Suitable colloids of the last mentioned types are
disclosed in United States Patents Nos 2,276,322, 2,276,323 and
2,397,866 Other suitable colloids include hydrophilic partially
substituted polyvinyl esters and acetals and the low substituted
cellulose esters of saturated aliphatic monocarboxylic acids of 2 to 4
carbon atoms and low substituted cellulose ethers, e g,
methylcellulose and ethyl-cellulose Additional natural colloids
include casein, albumin, gum arabic, agar agar and polyglycuronic acid
which are also anchored to supports by these new substrata.
The casting or extruding of the polyester film, coating of the
copolymer, heat-setting, colloid-coating and drying steps can be
carried out in an apparatus of the type described in United States
Patent No 2,627,088.
The heat-relaxing step following the drying step can be carried out in
another chamber 35 similar to the heat-setting and cooling zone o in
the apparatus of the aforesaid patent, but is preferably carried out
in a chamber where the film is in vertical paths and passes over and
under rollers The heat-relaxing 40 zone can be heated near the
entrance by infra-red lamps or electrically heated platens and then by
means of hot air or superheated steam.
The following examples will serve to illus 45 trate the invention but
are not to be regarded as limiting it in any way:EXAMPLES I-III A
molten ethylene glycol/terephthalic acid polyester having a melting
point of about 50 255 C is extruded through an elongated orifice
having the lips spaced about 90 mils apart onto a casting drum having
a peripheral speed of about 90 inches per minute to form a film about
38 mils thick The film 55 is biaxially stretched, first longitudinally
and then laterally, about 3 0 times in unit length and width at a

temperature of about 88 WC, heat-set under tension so that no
shrinkage occurs, and then given a second heat treat 60 ment A sample
of the resulting film and a sample of the film which did not receive
the second heat treatment were heated to a temperature of 120 'C for a
period of 5 minutes under no tension and the shrinkage meas 65 ured.
The following results were obtained with varying conditions: Second
heat treatment Shrinkage of Shrinkage Temperature of Temperature
Tension lbs /sq Time in sample not of sample heat-set O C inch minutes
subjected to subjected 0 C second heat to second treatment heat
treatment Ex I 150 119 75 5 1 05 % 0 07 % Ex H 180 132 12 2 0 95 % 0
06 % Ex III 210 146 185 3 0 88 % 0 08 % EXAMPLES IV-VI A film of
ethylene glycol/terephthalic acid polyester was cast as in Example I A
surface of the cast film was provided with a layer about 1 8 microns
thick of a vinylidene chloride/methyl acrylate/itaconic acid copolymer
( 90: 10: 2 by weight and made as described in Example I of United
States Patent No.
2,627,088) and dried at a temperature of about 92 'C The coated film
was biaxially stretched, first laterally and then longitudinally,
about 3 0 times in unit width and length 90 at a temperature of about
88 WC, heat-set under tension so that no shrinkage occurred and then
given a second heat treatment Samples of the film were tested as in
Examples I-III and the following results were ob 95 tained:Second heat
treatment Shrinkage qf sample not subjected to second heat treatment
Shrinkage of sample subjected to second heat h-eahnetlt 119 75 5 0 83
% 0 09 % 132 12 2 0 9 % 0 05 % 105 210 146 185 5 0 92 % 0 10 %
Temperature of heat-set rc.
Temperature Tension Ibs /sq Time in 0 C inch minutes Ex IV Ex V Ex VI
786,176 The base films of Examples IV, V and VI, when provided with a
thin gelatin substratum and coated with a gelatino-silver halide
emulsion layer showed good anchorage and dimensional stability when
developed washed, fixed and dried.
EXAMPLE VII
The process described in Example IV was repeated, substituting for the
vinylidene chloride/methyl acrylate/itaconic acid copolymer of that
Example a solution of the polyester of Example I of the United States
Patent No 2,698,239 in trichloroethylene.
The film was heat-set at a temperature of 180 C and the second heat
treatment was at a temperature of 138 'C, a tension of 40 pounds per
square inch and for a period of 2 l minutes A sample of the film, when
tested as in Examples I-Il exhibited a shrinkage of only 0 09 <
whereas a sample of the film which did not receive the second heat
treatment exhibited, under the same conditions, a shrinkage of 1 42
EXAMPLE VIII
The process described in Example IV was repeated substituting for the

vinylidene chloridel methyl acrylate/itaconic acid copolymer of that
Example a mixture of a polyester and an organic polyisocyanate of
Example I of United States Patent No.
2,698,241 The film was heat-set at a temperature of 1905 C, and the
second heat treatment was at a temperature of 119 'C _ a tension of
150 pounds per square inch and for a period of 2 minutes A sample of
the film, when tested as in Examples I-III exhibited a shrinkage of
only 0 075 ',, whereas a sample of the film which did not receive the
second heat treatment exhibited, under the samne conditions, a
shrinkage of 118 <-,.
EXAMPLE IX
The process set forth in Example IV was repeated substituting for the
vinylidene chloride/methyl acrylate/itaconic acid copolymer of that
Example an organic polvisocyanate of Example V of United States Patent
No 2,698,242 The film was heat-set at a temperature of 180 'C, and the
second heat treatment was at a temperature of 1329 C, a tension of 12
pounds per square inch and for a period of 2 minutes A sample of the
film, when tested as in Examples I-III exhibited a shrinkage of only 0
11 C ', whereas a sam Dle of the film which did not receive the second
heat treatment exhibited, under the same conditions, a shrinkage of 0
85 ;.
The uncoated biaxiallv oriented, heat-set heat-relaxed polyester films
obtainable in accordance with the invention have excellent dimensional
stability and are useful for many purposes where a dimensionally
stable self-supporting film is desired Among such uses are measuring
tape (where variation in dimension of the tape after the divisions of
length have been marked thereon will result in inaccurate measurements
a residual shrinkage of 1 in the tape resulting in an error of as much
as 1 foot in a 100 feet tape measure), transparent windows for
envelopes (where even slight shrinkage will cause 70 buckling of the
envelope in an undesirable manner), bottle, ap and other container
liners where shrinkage after the bottle or container is closed may
cause lealafe of the contents).
laminations with other ma-terials (where dif 75 ferences in shrinkage
of tle several layers wiil result in warping and uneven bending of the
composite structure package wrapping mnaterial, as for confectionery
cosmetics, foods and other materials (where shrink 80 age of the
wrapper subsequent to the wrapping may cause crack ino and tearing of
the wrapper if originally tightly wrapped or -may cause an unsightly
appearance if originally loosely wrapped to allow for 85 shrinkage),
storm window substitute for glass (where shrinkage of a Fat tightly
attached pane or sheet may cause tearing) dials drafting instruments
scales and reticles (where unchanging calibration is critical) These
and 90 many other uses for the polyester films obtained in accordance

with this invention are described in United States Patent No.
2,686,931.
Various radiation-sensitive materials may 95 be coated onto the
anchoring colloid layers of the light-insensitive films made in
accordance with this invention In addition to lightsensitive silver
salts, such as silver chloride.
silver bromide, silver chloride-bromide silver 100 chloride-iodide and
similar mixtures, there may be used bichromated hydrophilic colloids,
e g, albumin, gelatin gum arabic.
polyvinyl alcohols or glue The light-sensitive layers, of course are
applied in the ab 105 sence of actinic radiations Non-diffusing colour
formers, dye intermediates or dyes may be present in such layers Other
materials which mav be coated include 5 i 1 ht-sensitive iron salts
and diazonium compounds 110 with or without coupling con Inonents With
certain of these light-sensitive materials e g the diazo compounds the
binding agent may have a low sensitivity to water Thus polyvinyl
acetate or a cellulose acetate may be 115 used as the colloid binder.
The radiation-sensitive copolyrmer-coated biaxially oriented polyester
films made in accordance with this invention can be used for any
purpose including radiography por 120 trait photography, colour
photography, lithography and motion picture purposes The
non-light-sensitive base films are also useful for projection screens,
glazing (laminations for windows and surface protection) 125 The
production of dimensionally stable self-supporting polyester films in
accordance with this invention is simple, dependable and easily
controlled, it does not require complicated or expensive equipment and
can be 130 786,176 carried out on a semicontinuous scale The invention
is of particular value in providing photographic films bearing at
least one lightsensitive layer on a polyester base that is
dimensionally stable under conditions of processing and use even at
temperatures above -stretching temperatures.
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* 5.8.23.4; 93p
* GB786177 (A)

Description: GB786177 (A) ? 1957-11-13
An improved weld nut
A high quality text as facsimile in your desired language may be available
amongst the following family members:
BE551321 (A) FR1156716 (A)
BE551321 (A) FR1156716 (A) less
We, G K N GROUP SERVICES LIMITED,
a British Company, of London Works, Smethwick, in the County of
Stafford, 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 the class of nuts which has become known
under the term "weld nuts" and in which a nut is provided on one end
face with a plurality of small projections so that when it is desired
to secure the nut to a metal plate, the projections can be fused with
the metal of the plate by means of an electric current passed between
suitable electrodes, through the nut and the plate, pressure also
being applied to the nut, so that the nut becomes welded to the plate.
There have been in the past certain proposals for weld-nuts of square
shape having four projections, one at each corner of the nut, and such
projections have been either of hemo-spherical form or angular form
These are not entirely satisfactory from the point of view of
obtaining a good weld because they do not provide a good area of
contact with a plate for welding purposes and, particularly in mass
production, they cannot be relied upon to provide welding projections
which are all of equal height from the base of the nut, and for good

welding it is essential that the projections be all of equal height.
It is the object of the present invention to provide an improved weld
nut which will be free of these objections.
According to the present invention we provide a weld nut of square
form having on one end face an axially projecting spigot for locating
the nut over a preformed hole in 7869177 the plate to which it is to
be attached and four welding projections which are formed as arcuate
parts of an annular ring having 45 its centre coincident with the axis
of the nut.
The invention is illustrated in the accompanying drawings
wherein:Figure 1 is a perspective view of a nut.
Figure 2 is a plan view on the top 50 Figure 3 is a side view.
Figure 4 is a section taken diagonally.
In this example of a weld nut constructed in accordance with the
present invention the body of the nut is of square form and is 55
provided with a centrally disposed hole extending between the end
faces 10 and 11 and provided with the usual form of screw thread 12.
On one end face 10 there is formed a 60 locating spigot which takes
the form of a circular ring or boss 13 projecting axially from this
end face and concentric with the threaded hole and this locating
spigot serves to engage within a prepared hole in the plate 65 to
which the nut is to be attached so as to locate the nut in the correct
position for the subsequent welding operation The internal screw
thread extends also through the interior of this locating spigot 70
Also on this end face 10 the otherwise flat face of the nut is
provided with four welding projections 14 and these are formed at the
four corners of the nut as parts of an annular ring (see Figure 2)
which has its 75 axis coinciding with the axis of the threaded hole
such that four parts of this annular ring appear as raised projecting
ribs 14 which extend across the four corners of the nut.
At each corner the rib so formed is spaced 80 away from the extreme
corner point 15 of the face of the nut and is also spaced away from
the locating spigot so as to provide an air gap between the welding
projection and PATENT SPECFICATION Inventor: -NORMAN HECTOR NEWTON.
Date of filing Complete Specification: June 11, 1956.
Application Date: July 8, 1955 No 19769/55.
Complete Specification Published: Nov 13, 1957.
Index at Acceptance -Class 89 ( 1), A 7.
International Classification:-FO 6 b.
COMPLETE SPECIFICATION.
An Improved Weld Nut.
786,177 the locating spigot which prevents molten metal from entering
the threaded interior of the nut during the welding operation.
As the four raised ribs 14 at the corners of the nut are part of a

common annular ring there is a guarantee that they will be of equal
height which is essential for good welding characteristics.
At its other end the face of the nut may be provided with a shallow
recess 16 around the opening of the threaded hole for the purpose of
concentrating the flow of current during the welding operation in the
outer regions of the nut body so as to avoid any damage due to
overheating and deformation of the thread form as is more fully
explained in the Specification of our co-pending Application No
16113/55 (Serial No 775,724).
In previous proposals for weld nuts of square form having four
projections these projections have been provided by separate and
independent forms on a tool thus giving no guarantee of equality of
height between the projections whereas with the present invention the
four projections can be provided by means of tool forms which are part
of a common ring which ensures an equality of height in all the
projections produced on the face of the nut.
* Sitemap
* Accessibility
* Legal notice
* Terms of use
* 5.8.23.4; 93p
* GB786178 (A)
Description: GB786178 (A) ? 1957-11-13
Bis-mercaptomethyl aromatic compounds

COMPLETE SPECIFICATION Bis-Mercaptometbyl Aromatic Compounds
We, Esso RESEARCH AND ENGINEERING
COMPANY, a corporation duly organised and existing under the laws of
the State of Delaware, United States of America, of Elizabeth,
New Jersey, United States of America, do hereby declare the invention,
by which it is to be performed, to be particularly described in and by
the following statement:
This invention relates to improvements in or modifications of the
process described in our copending Application, No. 36131/54 (Serial
No. 783,546).
In the said cop ending application we have described a method for the
production of bismercapto aromatic compounds such as
bistnercaptomethyl durenes by reacting a bishaloaromatic compound such
as bis-chlorb methyl durene with a thiocompound such as a thiourea, a
thiocarbamate or a xanthate to form a thiouronium, thiocarbamate or
xanthate derivative and then converting this compound to the mercapto
derivative by hydrolysing the talouronium compound with aqueous alkali
or treating the thiocarbamate or xanthate compound with ammonia.
The bis-haloaromatic compound used as the starting material may be
represented by the formula ZCH2.Ph.CH2Z wherein Z is chlorine, bromine
or iodine, and Ph is a phenylene radical or a phenylene radical
substituted with 1 to 4 methyl groups. This type of material can be
prepared in a variety of ways as described, for instance, by M. J.
Rhoad and
P. J. Flory, J.A.C.S. 72:2216 i(1950).
Bischloromethyl-2,3,5,6-tetramethylbenzene, also known as
bis-chloromethyl durene and hereafter represented for the sake of
simplicity by the formula CH2.X.CWCl, is by far the preferred material
because of the unusual prb perties attributable to its fully
substituted ring structure. However, other known aromatic
bis-chioromethylated in the para position such as
para-bis-chloromethyl benzene or
2,5-bischloromethyl-1,4-dimethyl-benzene may be used similarly as a
starting material for linear fiber forming resins. Moreover, where the
linear nature of the final condensate is not of paramount importance
e.g. in molding resins or in insecticides, the two halomethyl groups
need not be in the para position and in such an event
bis-halomethylated mixed xylenes represent a particularly useful raw
material.
instead of the chloromethyl derivatives it will be understood that the
analogous bromomethyl or iodomethyl derivatives can be used similarly.

According to the process of the above Co- pending application the
mercaptan group may be introduced into the aromatic molecule by
reacting the above halo compound with a suitable thiocomnound
represented bv the formula
<img class="EMIRef" id="026598823-00010001" />
wherein Q is an amino group NR2 or an allroxy radicalORV, and Y is an
amino group - NR1V or thiol salt radical - SM, RIV being hydrogen or
an alkyl or aromatic radical of 1 to 8 carbon atoms such as methyl,
propyl, octyl, phenyl or xylenyl, R7 being an alkyl or aromatic
radical of 1 to 8 carbon atoms, preferably of 1 to 3 carbon atoms, and
M being sodium, potassium or an ammonium radical
The principal examples of such reagents are thiourea, CS(NH2),, alkali
metal thiocar- bamates such as sodium dithiocarbamate,
NaS.CS.NH2, and the alkali metal alkyl xanthates such as potassium
ethyl xanthate, KS.CS.OC2H,. Of coarse, depending on economic
considerations, various other alkyl or aryl substituted homologues of
any of the foregoing types of compounds can be used, e.g., tetramethyl
thiouree, CS(NMe2)2, ammos nium diisopropyl dithiocarbomate, NH4S.
CS .N(i-C3H7)2, diphenylthiocarbamic acid phenyl ester, Ph2N.CS.OPh,
or sodium octyl xanthate, NaS.CS.OCsH,7.
As an illustration bis-chloromethyl durene can be condensed with an
alkali metal alkyl xanthate as follow: -
(1) ClCH2.X.CH2Cl+ 2KS.CS.OR-- >
RO.CS.SCH2.X.CH2S.CS.OR+2KCL
The bis-alkyl xantbomethyl aromatic com pound produced as an
intermediate in the process of this invention will have the formula I,
shown above, wherein X represents a phenylene, dimethyl phenylene,
trimethyl phenylene or tetramethyl phenylene group and R represents an
alkyl radical of 1 to 8 carbon atoms.
The resulting bis - alkyl xanthomethyl aromatic intermediate can then
be reacted with ammonia to yield the desired bismercaDtan: -
<img class="EMIRef" id="026598823-00020001" />
(2b) RO.CS.SCH.X.CWS.CS.OR+ 2NH,
oHS.C:H2.X.CH2SH+ by-products
(e.g. xanthogen amide etc.).
The use of the base, referred to in the above cop enduing application
for the treatment of the bis-alkyl xanthomethyi aromatic compound
acording to the process of the above copending application has the
disadvantage that unless special precautions are taken substantial
amounts of by-products insoluble in allmali are formed and thus reduce
the yield of the desired bis-mercaptan.
It has now been found that if a weak base is used improved yields can
be obtained with a reduction in the amount of insoluble compounds.
The term weak base as used herein does not include ammonia and refers

to ionisable bases which are weaker bases, in aqueous solution, than
sodium hydroxide.
Examples d such weak bases are acid salts of hydrogen sulfide such as
potassium hydro gen sulfide, ammonium hydrogen sulfide, and sodium
hydrogen sulfide.
The present application relates to an improvement in or modification
of the process described and claimed in Application No.
36131/54 (Serial No. 783,546) for preparing a dimercaptan which
comprises reacting one mole of an aromatic dihalide, having the
formula ClCW.X.CH,G wherein X is a phenylene, momomethylphenylene,
dimethyl phenylene, trimethyl phenylene or tetramethyl phenylene
group, with 2 moles of an alkali metal alkyl xanthate, separating the
resulting aromatic xanthate product, heating the separated aromatic
xanthate product with a weak base in a ratio of at least 2 moles of
weak base per mole of said aromatic xanthate until a major proportion
of the xanthate is converted to the dimercaptan, dissolving the
resulting dimercaptan, in hot aqueous alkali, separating residual
undissolved solid from the liquid soludon, and precipitating the
dimercaptan from the solution.
The reaction between the aromatic dihalide and the alkali metal alkyl
xanthate is preferably carried out at 30 to 50" C.
EXAMPLE
The xanthomethyl derivative of bischioro methyl durene was obtained by
reacting bischloromethyl durene with an alkali metal alkyl xanthate
such as potassium ethyl xanthate, and sodium propyl xanthate as
described below.
A three-way flask equipped with a stirrer, a return condenser and a
thermomtr, was
charged with 211.2 gms. (1.32 mole) of potav
sium xanthate, and 900 ml. dimethylformamid as the preferred solvent.
Other sol.
vents which can be used in its stead include formamide, dioxane and
chloroform, though these will generally give much poorer yields.
138.6 gms. (0.6 mole) of bis-chloromethyl durene was slowly added to
the mixture of xanthate and dimethyl formamide with stirring and
sufficient cooling to keen the temerature at a moderate level, that
is, at about 30 to 40 C. Higher temperatures at this stage have an
adverse effect on yield. When all the dihalide had been added,
stirring at 40 C. was continued fcr three additional hours. At this
point, the mixture was cooled to a temperature below 0 C. specifically
to about - 5 C., and filtered. The precipitated aromatic xanthate was
slurried with water several times to remove the excess of potassium
xanthate and the potassium chloride formed.
When air dried, the bis-ethylxanthomethyl durene product consisted of

240 gms. of an almost snow-wllite powder melting at 179 C.
On recrystallization from dioxane it melted at 184 C. Compared with a
theoretical yield of 246 gms. the actual yield was almost
quantitative. This compound was than converted into the desired
bis-mercaptan as described below.
A 12-liter four-neck round bottom flask equipped with a stirrer,
condenser and a thermometer was charged with 3000 ml. of absolute
ethyl alcohol and 1500 ml. of an ethyl alcohol solution of potassium
hydrogen sulfide containing 0.21 grams KHS per ml. of solution The
mixture was heated to 75-80 C.
and 804 grams of bis-ethylxanthomethyl durene prepared as described
above was added to it The resulting mixture was then heated and
refluxes for 1.5 hours to form the dimercaptan. At this stage 400 ml.
of a 30% aqueous solution of sodium hvdroxide was added and the
mixture was reflexed for an additional hour. Finally the mixture was
poured into about thre times its volume of ice water acidified with
concentrated hydrochloric add until neutral as determined by a Congo
Red indicator, and filtered. The separated precipitate was reslurried
several times in water and air dried for three days. The air dried
material was distilled under a pressure of 1 mm. Hg. 331 grams of a
fraction boiling at 165--170" C. at this pressure was recovered,
leaving a small amount of higher boiling residue. The recovered
distillate consisted of pure bis-mercaptomethyl durene having a
melting point of 150 to 152 C. and corresponding to a yield of 82.3%
based on bisxanthomethyl durene. A substantially better yield could be
obtained with more careful handling. The purity of the product was
confirmed by elemental analysis.
The dimercaptan makes an ideal intermediate for the preparation of
linear polymers by condensation of the former with bifbnc- tional
reactant such as diacids, diacid chlorides, diolefins and dialdehydes.
The polymerization or condensation is best carried out in an inert
solvent such as xylene, toluene or ethylene chloride. For instance,
the dimercaptan may be condensed with adipyl chloride while in
solution in xylene. To bring about the condensation the reaction
mixture is heated in the absence of oxygen, e.g. in a nitrogen or
carbon dioxide atmosphere, until no more hydrogen chloride is given
off. At the beginning of the reaction, the mixture is homogeneous but
later becomes turbid, and finally the polyester precipitates as a
snowwhite powder. On completion of the reaction the mixture is
filtered, and the precipitate air dried either directly or, if quick
drying is desired, after washing with ether.
The polyesters have a melting point above 200 C. They can be readily
cold drawn to produce strong colorless filaments. Various mixtures of
two or more mercaptans e.g. of bis-mercaptomethyl benzene and

bis-mercaptomethyl durene, and/or of add chlorides, e.g.
adipic and terephthalic chloride, may be used to modify the properties
of the resins, e.g. to lower the melting point and so facilitate
extrusion.
What we claim is : -
1. An improvement in or modification of the process described and
claimed in Application No. 36I31/54 (Serial No. 783,546) for preparing
a dimercaptan which comprises reacting one mole of an aromatic
dihalide, having the formula ClCH2.X.CH2Cl wherein
X is a phenylene, monomethyl phenylene, dimethyl phenylene, trimethyl
phenylene or tetramethyl phenylene group, with 2 moles of an alkali
metal alkyl xanthate, separating the aromatic xanthate product,
heating the separated aromatic xanthate product with a weak base in a
ratio of at least 2 moles of weak base per mole of said aromatic
xanthate until a major proportion of the xanthate is converted to the
dimercaptan, dissolving the resulting dimercaptan in hot aqueous,
alkali separating residual undissolved solid from the liquid solution,
and precipitating the dimercaptan from the solution.
2. A process as claimed in Claim 1 wherein the weak base is an acid
salt of hydrogen sulphide.
3. A process according to Claim 1 or 2 wherein the weak base is
potassium hydrogen sulphide, ammonium hydrogen sulphide or sodium
hydrogen sulphide.
4. A process as claimed in any of Claims 1 to 3 wherein the separated
aromatic xanthate product is heated with the weak base in the presence
of ethyl alcohol.
5. A process as claimed in any of Claims 1 to 4 wherein the reaction
between the aromatic dihalide and the alkali metal alkyl xanthate is
carried out the presence of dimethyl formamide, formamide, dioxane or
chloroform.
6. A process as claimed in any of Claims 1 to 5 wherein the reaction
between the aromatic dihalide and the alkali metal alkyl xanthate is
carried out at 30 to 50 C.
7. A bis-alkyl xanthomethyl aromatic compound having the formula
RO.CS.SCH2XCH2
S.CS.OR wherein X represents a phenylene, monomethyl phenylene,
dimethyl phenylene, trim ethyl phenylene or tetramethyl phenylene
group and R is an allyl radical of 1 to 8 carbon atoms.
8. The improvement in or modification of the process described and
claimed in Specification No. 36131/54 (Serial No. 783,546)
substantially as hereinbefore described with particular reference to
the example.

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