4. VARIOUS TYPES OF
ADHESIVES
1.Latex Adhesive
2.Neoprene Adhesive
3.Polyurethane Adhesive
4.Hot-Melt Adhesive
5.Pressure Sensitive Adhesive
5. The Main Classes Of
Adhesive Used In Footwear
Industry
1.Vegatable Pastes
2.Rubber Latex
3.Natural Rubber Solution
5.Neoprene or Polychloropene Adhesives
6.Polyurethane Adhesive
7.Hot-Melt Adhesive
8.Nitrocellulose Adhesive
6. 1.Vegetable Pastes: It is made from starch or dextrin,
are mainly used in the trade for labeling boxes.
2.Rubber Latex: It is an aqueous emulsion of natural or
synthetic rubber stabilised with ammonia . It normally
contains 40 to 60 % solids. In sole attaching, this adhesive
is used mostly to the bond leather temporarily to natural
crepe.
3.Natural Rubber Solution: which is a solution of a
natural rubber dissolve in solvents such as carbon
tetrachloride or benzene, can be used for making
permanent bonds of crepe to crepe.
7. 4.Neoprene Adhesive: are more correctly called
polychlro-prene adhesive because Neoprene is the trade
name of DU Pont for polychlro-prene.
5.Poly-urethe Adhesive: It have different properties,
depending on their molecular structure . Although
aqueous poly-urethe emulsion are now being develop for
sole bonding, of resin but with some stabilizers.
6.Hot-Melt Adhesive: It have a plastics material rather
than synthetic rubber as their basic material. The most
successful are polyester or polyamide resins and, to a
lesser extent,EVA,a co-polymer of polyethylene and vinyl
acetate.
8. 7.Nitrocellulose Adhesives: are made from nitro-
cellulose dissolve in strong solvents of the acetone group
.these adhesive were the first synthetic adhesive used in
the footwear industry but really never satisfactory . They
have long since been replace by neoprene & polyurethane
adhesives.
9. The Selection Of Best
Adhesive
The main points to be considered when selecting
adhesives for footwear manufacture are:
1.Cost
2.Strength
3.Sutability for use with shoe materials
4.Sutability for shoe in processes
5.Shelf & pot life
6.General Considerations
10. PRECAUTIONS ON USE OF
ADHESIVES
Many adhesives are available for specific end use. one has
to find out an ideal adhesive for specific requirements.
The adhesive manufacturers have to educate the users
about the limitations on the use of individual adhesive and
train the operators on the proper use of adhesive materials.
Testing and establishment of realistic quantity control
procedures.
Safety in handling of materials,before,during and after use.
Customer service satisfaction requires a close working
relationship between the supplier and user.
11. Neoprene Adhesive
It is the generic term for synthetic rubber-like polymers
of- chlorobutadience(chloroprene),or copolymers with
chlorobutadience as the main constitutent.These are
usually dissolve in blends of aromatic aliphatic hydro-
carbons & polar solvents such as MEK . The blends of
solvents give adhesives with varying viscosities &
drying rates
As with more solvent baseadhesive,neoprene
can be applied by machine as well as by hand.
12. POLYURETHANE ADHESIVE
Polyurethane(P.U) is produced when a disocyanate
having two isocyanine groups is reacted with a diol
having two hydroxyl groups.
INGREDIENTS
Polyols having a molecular weight 1000.The polyols may
be polyether, polyester or polybutadiene based.
Diisocyanate:This is either toluene disocyanate(TDI)or
methylene bis (4,4;phenyl isocyanine)MDI.
Curing agent may be a short chain diol or triol for MDI
and an aromatic diamine for TDI.
13.
14. HOT MELT ADHESIVE
These are of cent percent solid content and are free from
solvents. The availability of a variety of polymers with a
broad spectrum of properties tailored for a specific end
use, is an added advantage. Today hot melt formulations
are available for temporary as well as permanent
attachment in shoe manufacture.
Usually supplied to footwear industry in the form of
granules and rods (in coils).When these adhesives
heated to high temperature, they melt rapidly into a
fluid, flow freely on bonding sites, wet the surfaces,
quickly cool, solidify to a crystalline solid and thereby
adhere to give good bond strength between the two
surfaces.
15. HOT MELT ADHESIVE
USED IN THERMOFOLDING MACHINES
AMBER COLOURED
STITCHED AS IT IS NOT A PERMANENT
BOND
16. PROPERTIES
Amber coloured.
Polyamide is used instead of polyester due to its
flexibility, low melting point and availability in either
granular, rod or block form.
Toe puffs,stiifeners,backing cloths and lining material,
for lamination could be precoated (either overall,or
splattered)with hot melt adhesives and they attached by
pressing under heated plates(hand iron, laminating
press).
It must be stitched as it’s not a permanent bond.
17. USAGE
Hot melt adhesives are used in shoe upper assembly for
attaching linings to uppers and edge bonding. Textile
linings with thermo cement coatings or film adhesives is
kept on the upper and attached by ironing. Bonded
surface presents a clean, uniform and neat appearance
with a rapid setting. The cement is also extruded as in
the thermocementing,folding and attaching machine.
18. TESTS FOR ADHESIVES
VISCOSITY: The object of this test is to get an idea of information
regarding the age,quality,stability,solids content, molecular weight
and specific gravity of the adhesive.
DRYING TIME: The adhesive is applied by the brush to the surface
of the material. The time at which the adhesive film develops
tackiness as its starts sticking to the finger.
TACK: The force required to separates two surfaces, one of which
has been coated with an adhesive after they have been in contact
over a specified area at a specified pressure for a specified time.
Tensile testing machine is used and the results are given in
pounds/sq inch required to part the test blocks.
19. SHELF LIFE: The viscosity of the same adhesive sample is
determined periodically at the regular intervals of time,the
results are compared with that of the value of a fresh sample
or original shape.
POT LIFE: It is determined by noting down the changes in
viscosity or bond strength, but the test methods should be as
agreeable between the adhesive manufacturer and the user
PEEL STRENGTH: Peel strength of an adhesive in kg./cm
width obtained by peeling the two surfaces and recording the
adhesive strength. The objective of this test is to get an
information as to the behavior of the adhesive to an
andherend i.e., bond strength.
20.
21. SEAM TAPES
THERMOPLASTIC ADHESIVE FILM APPLIED TO
SEWN SEAMS OF FABRICS TO PREVENT WATER
FROM LEAKING THROUGH THE SEAMS
APPLIED BY USING AIR TAPING MACHINES, LASER
OR ULTRA SONIC MACHINERY.
E.g. CREPE PAPER TAPE, LIGHT/MEDIUM COTTON
SHEETING ETC.
22. strap and stripping
reinforcement
NYLON COATED CUT TAPE: COATED 1 OR BOTH
SIDE(S) FOR STRAP AND STRIPPING
APPLICATIONS
NYLON CUT TAPE: COATED BOTH SIDES FOR
BUCKLE HOLES IN WIDER STRAPS
NON-WOVEN TAPE: COATED 1 OR 2 SIDE(S) RAW
EDGE STRAPS ETC
23. FACING AND TRIM REINFORCEMENT
COATED LIGHT COTTON DRILL TAPE: FLEXIBLE AND
HIGH QUALITY
COATED COMPRESSED PAPER TAPE: GOOD
RESISTANCE TO COMPRESSION AND USED IN EYELET
ATTACHMENT
COATED NON-WOVEN POLYPROPYLENE TAPE:
LIGHT WEIGHT WITH GOOD TEAR RESISTANCE AND
IT HAS HIGH STRENGTH
COATED NON-WOVEN POLYESTER TAPE: HIGH
PERFORMANCE AND USED FOR ALL METALLIC
FASTENINGS.
THANK YOU.
