JPS6361352B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD This invention relates to methods of coating surfaces, and more particularly to methods of adhering surfaces, such as tread elements, to shoe uppers. An important requirement when attaching tread elements such as outsoles to shoe uppers is that the adhesive must be applied in a fluid state so that the surfaces to be joined are wetted and can penetrate to some extent. That's true. It is also an important requirement that the adhesive be tough and strong afterwards. Initial fluidity was achieved by using a solution of the adhesive in a volatile organic solvent. In this case, strength and toughness are obtained by evaporation of the solvent after application. However, solvent-based adhesives take a long time to dry and pose fire and health hazards from solvent vapors. Hot-melt adhesives have also been used with some success, but require relatively high temperatures to reduce the viscosity of the adhesive for sufficient wet adhesive engagement with the surface, and problems with adhesive degradation and In some cases, problems arise with damage to the surfaces to be bonded. Moreover, the relatively short opening time imposes unduly stringent time requirements for bringing the two surfaces together while the adhesive is still in a flowing state. It is an object of the present invention to produce adhesives or resins which are initially fluid at relatively low temperatures and which can readily enter into wet adhesive engagement with surfaces and which, by relatively mild processing, can be made into tough solid but compatible adhesives or resins. It is an object of the present invention to provide a method for coating and bonding surfaces using a coating material that can be transformed into a heat-softened state that forms a strong adhesive bond with the surface almost immediately. For this purpose and according to one embodiment of the invention, polymerizable urethane polymers containing reactive -NCO groups and crystalline segments in the molecule and having a relatively low crystalline melting point are compared in a free-flowing state. It is applied to a surface at a relatively low temperature and brought into wet adhesive engagement with the surface. This polymerizable urethane polymer coating is transformed into a tough solid state by reacting with a chain extender containing a compound having active hydrogen that is reactive with the -NCO groups in the urethane. After the chain-extended coating is assembled into adhesive engagement in a heat-softened state with a compatible second surface to be bonded to the surface,
It can be cooled to form a strong and strong bond. The method of the present invention is primarily useful for bonding, and is particularly useful for bonding tread members to shoe uppers;
Therefore, this application will be specifically explained below. However, in some aspects, the method of the present invention
It is also useful for coating and bonding other surfaces such as resin or rubber materials, metals and textiles, and for reinforcing and stiffening sheet materials, such as the toe or heel skin of shoes. As shown in FIG. 1, in the adhesive outsole bonding method, a band 10 of fluid urethane adhesive is applied to the adhesive edge of an outsole 12, preferably with an outsole adhesive applicator 14. Outsole adhesive applicator 14 includes a nozzle 16 for applying adhesive, a drive wheel 18 for moving past outsole 12 at a desired speed, and an edge of outsole 12 in a desired relationship with respect to nozzle 16. It consists of a guide 20 for holding it in place. As can be seen in FIG. 1, the adhesive applicator applies the band 10 over at least the entire front portion of the outsole 12, but depending on the construction of the shoe being manufactured, the adhesive applicator may apply the band 10 over the entire edge of the outsole. It can also be painted. The adhesive surface on the bottom of the upper can also be coated with the same or another compatible adhesive. The applied urethane adhesive is then exposed to moisture, preferably in a steam chamber or other humidifying device, and preferably heated to some extent to cause chain extension of the adhesive. After performing the adhesive chain extension, the outsole 12 and the bottom gluing surface 2 are bonded to complete the outsole gluing process.
4 and the upper 22 with adhesive attached thereto are placed on a rack 26 spaced apart from a radiant heating device 28, and the adhesive is heated above its crystalline melting point to cause the adhesive to become viscoelastic. (see Figure 2).
After heating the adhesive on the bottom of the upper 22 and the outsole 12, the outsole 12 is placed on the bottom of the upper 22;
The combination of the outsole 12 and the upper 22 is placed in an outsole bonding press 30 (see FIG. 3), and pressure for outsole bonding is applied. The method of the present invention provides new benefits due to the crystallinity of the resin segments and the relatively low molecular weight of the adhesive, as well as the development of an ordered sequence of physical properties caused by temperature and chemical effects on the adhesive. The adhesive can be applied in a liquid form either by heating to melt it or by adding a solvent. If the adhesive is applied in the molten state, the adhesive need only be elevated above the crystalline melting point of the resin segment to provide the fluidity necessary to bring it into wet adhesive engagement with the surfaces to be bonded. “Crystalline melting point”
The term refers to the temperature at which the crystalline segment of a polymer melts, measured as the temperature of the main endothermic peak in differential thermal analysis. When the polymer is activated above this temperature, the crystalline segments melt and softening of the polymer coating or film occurs. After application, bring the adhesive below the crystalline melting point,
It is crystallized to provide resistance to flow and deformation at the temperatures used in subsequent steps. The adhesive can be dissolved in an inert volatile solvent to form a liquid for application at room temperature or at a slightly elevated temperature. A volatile organic liquid containing no active hydrogen can be used as the solvent. Solvents used include xylene, toluene, dimethylformamide, acetone, methyl ethyl ketone,
These include ethyl acetate, cellulose acetate, methylene chloride and mixtures thereof. A particularly useful solvent has been methylene chloride or a mixture of methyl ethyl ketone and toluene at up to about 85% by weight based on the weight of the solvent mixture. Due to the nature of the urethanes used in the present invention, even solutions with relatively high solids contents, eg, 60% by weight or more, have low viscosity, so that they can be applied well in wet engagement with the surface. Lower percentages of solvent may be used if it is desired to apply the urethane at a somewhat higher temperature than would be required to melt the urethane in the absence of a solvent. If the applied adhesive is a solution, the solvent is evaporated before further processing. In a step subsequent to the formation of the adhesive coating, the active isocyanate groups of the adhesive are treated with a chain extender that provides at least two active hydrogens, such as water vapor, or a similar chain extender at moderately elevated temperatures, i.e., at a warm temperature. The reaction renders the adhesive into a tough, flow-resistant, but heat-softening state. In the chain-extended state, the crystalline melting point is almost the same as the original urethane adhesive, so when heated above the crystalline melting point the chain-extended adhesive becomes viscoelastic, i.e. somewhat rubbery; Compatible surfaces such as wood, metal or textile surfaces or resins such as vinyl resins that are capable of deforming and flowing under pressure and are tacky and coated with the same or compatible adhesive. Adhesive bonding to surfaces is possible. Because the chain-extended adhesive becomes viscoelastic and somewhat rubbery at temperatures above its crystalline melting point,
The bond obtained by bringing this adhesive surface into contact with another surface has a very high initial bond strength, so that, for example, when bonding an outsole and an upper, the elasticity of the outsole causes the outsole to The tendency to separate from the carapace disappears. Adhesives that produce favorable physical states through subsequent physical and chemical treatments are reactive-
Based on polyurethane with NCO groups,
A prepolymer containing terminal -NCO groups obtained by reacting a relatively low molecular weight polyol with an excess of diisocyanate, preferably having a crystalline melting point range of about 40°C to about 90°C, preferably about 40°C to 65°C. Based on. Suitable polyols include polycaprolactone containing terminal hydroxyl groups and sebacic acid,
An aliphatic dicarboxylic acid having 6 to 12 carbon atoms, such as adipic acid, azelaic acid, suberic acid, dodecanedioic acid, and a preferably even glycol having 2 to 6 carbon atoms, such as 1,4-butanediol. Contains polyester. The acid component of the polyester polyol includes from about 5% to about 25% by mole of an alicyclic acid such as 1,4-cyclohexanedicarboxylic acid or 1,2-cyclohexanedicarboxylic acid to promote adhesion to the resin-rubber surface. % and may contain from about 5% to about 25% on a molar basis an aromatic dicarboxylic acid such as terephthalic acid or isophthalic acid to improve plasticizer resistance. The glycol component may contain from about 5% to about 15% on a molar basis a cycloaliphatic glycol, such as diethylene glycol or 1,4 cyclohexanedimethanol, to improve tack and wettability and improve reactivity with water vapor. can. The molecular weight range of the polyol should be from about 1,000 to about 10,000, preferably from about 2,000 to about 4,000. The polyurethane applied to the surface to be bonded contains one or more of the above polyols and diisocyanate,
It is produced by reacting at a ratio such that the -NCO:-OH ratio ranges from about 1.5 to about 3.0.
Any available diisocyanate can be used, including tolylene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate. Preferably, the polyurethane is produced without the use of a catalyst;
It may also be desirable to include a stabilizer such as an acid chloride such as benzoyl chloride, acetyl chloride or sebasoyl chloride in an amount of about 0.05 to about 0.2% by weight of the polyurethane. It has been found that although polyurethanes made using diphenylmethane diisocyanate react with water more rapidly than polyurethanes made using tolylene diisocyanate, the latter polyurethanes are more stable during storage. Polyurethanes with rapid reactivity and good storage stability are obtained by using both diisocyanates in combination. Since the reaction rates are different, it is preferable to add tolylene diisocyanate first and react for a certain period of time to react the -NCO group at the para position with the polyol, and then add diphenylmethane diisocyanate. Useful ratios of these diisocyanates range from equal parts on a molar basis to 80 moles of diphenylmethane diisocyanate and 20 moles of tolylene diisocyanate. The rate of chain extension reactions in the urethane layer can be increased by the use of catalysts. For chain extension with moisture, tertiary amines such as N-methylmorpholine, triethylene diamine and other known catalysts such as dibutyltin dilaurate, stannous octylate can be added to the urethane. Generally, about 0.05 to about 1% by weight based on the weight of urethane
of catalyst can be used. Although urethanes make excellent adhesives or coatings on their own, it may be desirable to include other materials such as plasticizers, fillers, and adhesives.
Plasticizers, particularly solid plasticizers, are of value both in reducing the viscosity of the urethane in the hot melt state and in improving the performance of the final film. Plasticizers useful for adding to urethanes include dicyclohexyl phthalate;
These include triphenyl phosphate, diphenyl phthalate, cycloaliphatic epoxides or bisphenol A type epoxy monomers. Adhesives useful in improving the achievement of adhesive relationships include hydrocarbon-type adhesives such as terpenes, alpha and beta-pinene polymers, low molecular weight styrenes such as polyalphamethylstyrene, and rosin esters. . Urethane compositions generally include clay, carbonate,
Inert fillers such as titanium dioxide and others may be added. It has been found that the reaction of the diisocyanate with the polyol raises the crystalline melting point by only a few degrees above the crystalline melting point of the polyol itself.
For example, butanediol sebacate polyol has a crystalline melting point of 49°C, but when this polyol and diphenylmethane diisocyanate are combined,
The crystalline melting point of the polyurethane obtained by reacting with the NCO:1-OH ratio is only 54°C. The polyurethane can be applied to surfaces such as the outsole adhesive surface or the outsole adhesive surface of the sole of the upper in a fluid state by conventional applicator equipment or even by hand. Solvent-free polyurethane, which has a crystalline melting point of about 70°C, has a relatively low temperature, e.g.
Application temperatures between 100°C and 100°C have been found to be useful. Solvent-borne polyurethane compositions can be applied at room temperature or at slightly elevated temperatures. It is desirable that the thickness of the urethane coating be uniform so that the action of the chain extender is uniform throughout the thickness of the urethane coating or filler. Preferably, the coating thickness is from about 0.025 mm to about 0.127 mm to provide the most complete and uniform chain extension throughout the thickness of the coating. For relatively regular surfaces such as the adhesive surface of the outsole, a relatively thin coating such as 0.025 mm is effective, while for irregular surfaces such as the adhesive surface of the outsole of the upper, a coating as thin as 0.075 mm is effective. A coating can be applied. After application of the polyurethane, the resulting coating is preferably crystallized before chain extension is performed.
That is, the crystallization that occurs prevents the coating from deforming or flowing at higher temperatures than the coating is exposed to during the chain extension step. In order to bring the applied polyurethane into the desired state for bond formation, a chain extension process is performed, which changes the coating surface to the -NCO of the polyurethane.
It consists of exposure to a compound with two active hydrogens that react with the group. Preferred chain extenders are water,
Preferably water is in the form of steam, for example in a humid room or in the vicinity of a steam source. Other chain extenders such as diamines and glycols can also be used. The temperature for chain extension is preferably slightly higher than room temperature, about 32°C at a relative humidity of about 50 to about 95%.
~88℃ without the urethane coating deforming
It was found to be effective in performing chain extensions at a reasonable rate of 10 to about 30 minutes. Chain extension reactions are attacked by thermal activation, which renders the membrane elasto-plastic but still soluble in active polyurethane solvents such as dimethylformamide and tetrahydrofuran. After carrying out the chain extension (where the chain extension ends no sooner than the end point of the reaction is reached, i.e. at an intermediate stage of the reaction) and removing free water or other chain extender from the urethane coating surface,
The coating can be heated to an active adhesive state. Although radiant heating is preferred, other forms of heating such as convective heating can also be used. Heating is carried out to bring at least the urethane coated surface to a temperature above the crystalline melting point rapidly, preferably within 15 to 30 seconds, preferably in the range of about 49°C to about 82°C, and at least the surface of the vinyl resin is heated. The coating should be in a viscoelastic state such that it can adhesively bond with the adhesive layer of the article to be bonded to a compatible surface or coating surface. When using a urethane with a crystalline melting point up to 70°C, excellent adhesion was obtained at a bonding temperature about 5°C higher than the crystalline melting point. Completing the adhesive bond consists of bringing together the surfaces with the heat activated urethane in between and applying pressure to the assembly to ensure good engagement throughout. After the surfaces are first brought together and before pressure is applied, a limited amount of relative movement of the surfaces to be joined is allowed due to the adhesive's viscoelastic state; It was found that a good adhesion was obtained. The final bond obtained when this urethane adhesive is cooled has excellent toughness and flexibility, and this urethane adhesive is used in shoes whose outer soles are bonded with this adhesive. It can withstand the stress that occurs. Although the coating or adhesion method of the present invention has been described above with respect to applying the adhesive in a fluidized molten state or a molten state, the method of the present invention uses a chain-extended adhesive as a supported film or a single film; It can also be carried out by adhering to compatible surfaces as a coating in a thermally activated state, or by using it as an adhesive between compatible surfaces to bond the surfaces together. Examples are shown below to facilitate understanding of the present invention. It goes without saying that the invention is not limited in detail to the particular ingredients, ratios and operations described in the examples. Example 1 Adipic acid butanediol polyester containing a terminal hydroxyl group with a molecular weight of 2600 and a crystalline melting point of about 49°C and diphenylmethane diisocyanate were prepared.
A prepolymer containing terminal -NCO groups is produced by reacting at a ratio where the NCO:-OH ratio is 1.5. The resulting prepolymer has a melting point of approximately 54°C and 100°C.
It is a fluid with a viscosity of approximately 8000 cps. The melting points shown in this example and the following examples are crystalline melting points determined as an endothermic peak by differential thermal analysis. Melt this prepolymer and raise the temperature to 100℃,
A thickness of 0.075 mm is applied to the pre-roughened leather shoe upper outer sole adhesive surface and the compounded outer sole adhesive surface of vulcanized butadiene styrene copolymer synthetic rubber.
Apply as a coating. The resulting coating is placed in a high humidity atmosphere on a steam table at 70°C.
Exposure for 15 minutes allows the -NCO groups of the prepolymer to react with the water and cause chain extension. After completion of this treatment, the coating is tough and strongly adheres to the adhesive surface, and at about 65° C. it softens to an adhesive tack to similar adhesive surfaces. The coating on the adhesive surface was then subjected to infrared heat activation for 30 seconds in a radiant heat activation device set at 60% input power. Press the outsole against the adhesive surface of the upper sole. Spotting tack is excellent. This combination is pressed in an outsole adhesive press to ensure complete adhesion. A strong initial bond is formed and there is no peeling, i.e. “grlnning”.
This adhesive strength is considered to be sufficient for shoes. Example 2 Test strip 2.54 of the materials listed in Table 1 below.
cm x 17.78 cm is coated with the molten prepolymer of Example 1 at 80-90°C to create a 0.075 mm thick coating. 15 minutes after applying the coating,
The strip is left in a high humidity atmosphere on a steam table at 70°C or in a room at a temperature of about 38°C and a relative humidity of 68% for the time indicated in the table to allow the -NCO groups in the coating to react with water. cause chain extension. The strips are then activated with infrared heat in a conventional radiant heat activation apparatus (RHA) with the activation apparatus heating set at 60% power. This activation raises the temperature of the coating on the strip to about 68-75°C. After the activated strips are combined in pairs as indicated in the table and pressed to achieve complete adhesion, the combined strips are cooled to room temperature and tested for adhesion. The test results are shown in the table.

[Table] ℃

[Table] Fee
RF=Rubber break, VF=Vinyl break, LF=Leather break Example 3 2 parts of diphenylmethane diisocyanate and 1 part of tolylene diisocyanate in a molar ratio of adipic acid butanediol polyester containing terminal hydroxyl groups with a molecular weight of 3000 and a melting point of about 50°C. A terminal -NCO group-containing prepolymer is produced by reacting with a mixed diisocyanate at a -NCO:-OH ratio of 2.0. The resulting prepolymer has a melting point of approximately 54°C.
It is a fluid with a viscosity of approximately 11,000 cps at 100°C. Outsole sheet material purchased as surface chlorinated "Kraton" (which is a surface chlorinated styrene-butadiene block copolymer), polyvinyl chloride outsole sheet material and styrene-butadiene copolymer. 2.54 from in vitro sole raw materials
A test strip measuring cm x 17.78 cm was cut. Test strips were also cut from a lined polyvinyl chloride material called "Pattina" and an upper material containing leather. These strips of outsole material were coated with molten prepolymer at 80°C to 90°C to create a 0.075mm thick coating, and after the coating had cooled.
Strip the strips on a steam table at 70℃ RH90
% in a high humidity atmosphere for about 15 minutes. For upper material strips, the backed PVC upper material is coated with solvent-based polyurethane (Estane) adhesive and the leather upper material is coated with solvent-based phenolic resin-polychloroprene outsole bonding cement. was applied. In either case,
The resulting adhesive coating was dried to remove the solvent. The adhesive coated outsole material and upper material strips were activated by placing them in a radiant heat activation device with a radiant heating device set at 55% power for 10 seconds. The surface temperature of the adhesive on the strip surface is approximately 80
It was warm at ℃. A strip of adhesive-coated backed PVC upper material is combined with a strip of adhesive-coated block copolymer outsole material and a strip of styrene-butadiene copolymer outsole material, and the adhesive-coated leather is combined with a strip of PVC upper material. Combined with the outsole material, these combinations were pressed to completely adhere. When tested after 7 days, the peel bond strength was 14.06 Kg per linear inch between the PVC material and the block copolymer;
Between the leather and the polyvinyl chloride outsole material, it was 12.25 kg per linear inch, and between the polyvinyl chloride material and the styrene-butadiene copolymer outsole material, it was 17.69 kg per linear inch. Example 4 Diphenylmethane diisocyanate and molecular weight approx.
2860, with polycaprolactone having a melting point of about 54°C, to form terminal -NCO with a free -NCO group content of 2.18%.
A group-containing prepolymer was produced. Melt this prepolymer and bring the temperature to 100℃,
Thickness on the surface of the pre-roughened styrene-isoprene-styrene block copolymer outsole material
Applied as a 0.075mm coating. Place the resulting coating on a steam table at 70°C.
Exposure to a high temperature range of 95% RH caused the -NCO groups of the prepolymer to react with water to cause chain extension. A viscous adhesive solution having a solids content of about 20% was prepared by dissolving a thermoplastic linear polyester urethane elastomer in a solvent mixture of approximately equal parts of tetrahydrofuran and methyl ethyl ketone. This urethane elastomer is a commercially available product ("estane"), contains almost no crosslinks, and has 1 mole of terminal -
It is obtained by reacting an OH group-containing polyester, aliphatic glycol, and diphenyl diisocyanate at a ratio that leaves almost no unreacted isocyanate groups or hydroxyl groups. The viscosity of the obtained solution measured with a Bruckfield viscometer was about 2000 to 3000 cps at room temperature. The solution-based adhesive described above was brushed onto the surface of a polyvinyl chloride upper material that had been previously lined with a roughened cloth. Twenty-four hours after applying the adhesive to the polyvinyl chloride material as described above, the coating was activated by infrared heating in a radiant heat activation device with a heating device set at 60% input. The heat activated polyvinyl chloride backing material was applied adhesive side up to a similarly heat activated adhesive coating on the block copolymer outsole material. Spotting tack was good. This combination was pressed together to ensure complete adhesion. Initial adhesion as determined by peel pull testing was 6.80 to 9.07 kg per linear inch. When the adhesion was tested after 7 days, the peel adhesion strength was 20.41 kg per linear inch and failure occurred in the block copolymer. Example 5 The procedure of Example 4 was repeated. However, a styrene-butadiene copolymer rubber outer sole material was used instead of the block copolymer material. The combination of upper material and outsole material has good initial tack.
It exhibited very good initial bond strength, with a peel bond strength of 17.69 kg per linear inch after 7 days. In this case, a break occurred in the backing polyvinyl chloride upper material. Example 6 The following prepolymers containing terminal -NCO groups are prepared by reacting polyols with diphenylmethane diisocyanate at the -NCO:-OH ratios shown in Table 2. The polyol of Prepolymer 2 is polycaprolactone with a molecular weight of 2890 and a melting point of about 56°C, and this prepolymer combines the above polyol and diphenylmethane diisocyanate into -NCO:-OH
It is produced by reacting at a ratio of 1.75. The polyol of prepolymer 3 has a molecular weight of 2000 and a melting point of approx.
It is a butanediol sebacate polyester containing terminal -OH groups at 64°C, and this polyol and diphenylmethane diisocyanate are combined into -NCO: -OH
Prepolymer 3 is produced by reacting at a ratio such that the ratio is 1.75. 2.54cm x 17.74cm of the materials listed in Table 2
The test strip was coated with molten prepolymer at 80°C to 90°C to create a 0.075 mm thick coating. 15 minutes after applying the coating,
The strips were placed in a high temperature atmosphere on a 70°C steam table for 15 minutes to ensure that -
The NCO group was reacted with water to cause chain extension. The strip is then placed in a conventional radiant heat activation (RHA) device and activated by infrared heating for 30 seconds with the activation device's heating device set at 60% power. This activation raised the temperature of the coating on the strip to about 68°C to 75°C. The activated strips are then brought together in pairs as listed in Table 2, pressed to ensure complete adhesion, cooled to room temperature and tested for adhesion. The test results are shown in Table 2.

[Table] Example 7 Adipic acid butanediol polyester containing a terminal hydroxyl group with a molecular weight of 2600 and a crystalline melting point of 49°C and diphenylmethane diisocyanate were
A prepolymer containing terminal -NCO groups is produced by reacting at a ratio where the NCO:-OH ratio is 1.5. The resulting prepolymer has a melting point of approximately 54°C and 100°C.
This results in a fluid with a viscosity of approximately 8000 cps. This prepolymer was dissolved in a mixed solvent of 4 parts of methylene chloride and 1 part of toluene to prepare a solution with a solid content of 60% by weight. The viscosity of this solution was approximately 1500 cps. This solution is applied to the surface of the leather upper material, which has been roughened in advance, and the outer sole material, which is compounded with vulcanized butadiene styrene copolymer synthetic rubber, has a surface thickness of 0.127 mm.
coatings and each coating was allowed to dry. This coating was exposed to a high humidity atmosphere on a 70°C steam table for 15 minutes to cause the -NCO groups of the prepolymer to react with the water and cause chain extension. After this treatment, the coating is tough and has the ability to strongly adhere to the surface and soften to a tacky state adhesive to similar adhesive surfaces at temperatures of about 65°C. This coating is placed in a radiant heat activation device and subjected to infrared heat treatment for 20 seconds with the heating device set at 55% input. Bring both surfaces together and press to ensure complete adhesion. When testing after 7 days,
Peel adhesion strength was 18.14 kg per linear inch. Example 8 A prepolymer solution was prepared in the same manner as in Example 7 except that 0.25% dimethylpiperazine was included based on the weight of the prepolymer. This solution was applied to leather and vulcanized butadiene styrene copolymer synthetic rubber, and the resulting coating was dried as in Example 7. This coating is applied at 85°C and at a relative humidity of only 18°C.
Exposure to ~20% atmosphere for 15 minutes caused chain extension, rendering the coating tough and strongly adhesive. The coating was then heat activated and the leather and synthetic rubber were then pressed together as described in Example 7. Peel adhesion strength after 7 days was 18.14 kg per linear inch. Example 9 Polycaprolactone having a molecular weight of 2860 and a crystalline melting point of 54°C is reacted with diphenylmethane diisocyanate in a ratio such that the free -NCO content is 2.18% to produce a prepolymer containing terminal -NCO groups. This prepolymer was dissolved in toluene to reduce the solid content.
Make a 60% solution by weight. This solution is applied as a 0.127 mm thick coating to the surface of the pre-roughened polyvinyl chloride adhesive backing material and to the surface of the styrene butadiene styrene block copolymer compounded outsole material. The resulting coating was exposed for 30 minutes to an atmosphere of 90% relative humidity on a steam table at 70 °C,
-NCO groups of the prepolymer were reacted with water to cause chain extension. After this treatment, the coating is tough, strongly adheres to the surface, and has the ability to soften to a tacky state adhesive to similar adhesive surfaces at temperatures of about 65°C. This coating is placed in a radiant heat activation device and activated by infrared heating for 20 seconds with the heating device set at 55% input. Both surfaces were brought together and pressed to ensure complete adhesion. When tested after 7 days, the peel adhesion strength was 1.
The weight was 19.05 kg per linear inch.

[Brief explanation of drawings]

FIG. 1 is a partially removed schematic angular view of the outsole adhesive applicator for applying a strip of adhesive onto the gluing edge of the outsole; FIG. FIG. 3 is a schematic front view showing the activation of the adhesive on the upper, and FIG. 3 is a schematic front view showing the bonding of the outsole to the upper in an outsole bonding press. Explanation of drawing number, 10...Adhesive strip, 12...
... Outsole, 14 ... Outsole adhesive applicator, 22 ... Upper, 24 ... Upper surface for adhesion, 28 ... Radiant heating device, 80 ... Outsole adhesive press.

Claims (1)

[Claims] 1. A method for bonding a surface containing a reactive -NCO group and at a temperature of about 40°C to about 90°C.
a polymerizable urethane polymer having a crystalline melting point in the range of about 1.25:1 to about 3.0:1 and which is viscoelastic when heated above the crystalline melting point after chain extension; −NCO within the range of 1:
A terminal obtained by reacting a diisocyanate and a polymerizable polyol in a ratio that gives the -OH ratio -
applying the prepolymer containing NCO groups as a coating to the surface of the first article in a fluidized state, the prepolymer having a molecular weight in the range of about 1000 to about 10000; A compound that provides water in the form of steam or water vapor is contacted with the polymerizable urethane polymer to react with the reactive -NCO groups to cause chain extension, and the chain-extended urethane polymer is adjusted to its crystalline melting point. heating to a higher temperature to a heat-softened viscoelastic state and forming a heat activated adhesive on the attachment surface of the second article which is compatible with the chain-extended urethane polymer in the viscoelastic state. Press onto the coating,
An adhesion method comprising the steps of: next cooling the chain-extended urethane polymer and adhering it to the first article in a tough and firm state. 2 The polymerizable polyol is a terminal hydroxyl group-containing polyester of the group consisting of polycaprolactone and an aliphatic polyester of a dicarboxylic acid having 6 to 12 carbon atoms and a glycol having 2 to 6 carbon atoms, is about
It has a molecular weight of 2000 to about 4000, a crystalline melting point of about 40°C to about 60°C, and a -NCO:-OH ratio of about 1.5:1 to
The diisocyanate and the polyol are reacted in ratios ranging from about 2.5 to 1, brought into a fluid state by heating the prepolymer above its crystalline melting point for application as a coating, and the chain extension described above. Claims characterized in that the polyurethane is brought into a viscoelastic state by heating to a temperature at least 5° C. above its crystalline melting point and then pressed to adhere to the adhesive coating on the second article. The method described in item 1. 3. The polymerizable polyol is a terminal hydroxyl group-containing polyester of the group consisting of polycaprolactone and an aliphatic polyester of a dicarboxylic acid having 6 to 12 carbon atoms and a glycol having 2 to 6 carbon atoms; has a molecular weight of about 2000 to about 4000 and a molecular weight of about 40℃ to about 60℃.
The diisocyanate and polyol are combined in a -NCO:-OH ratio of about 1.5:1 to about 2.5.
The prepolymer is brought into a fluid state by dissolving it in a volatile organic liquid for application as a coating, and the chain-extended polyurethane is brought to its crystalline melting point. Claim 1, characterized in that the second article is brought into a viscoelastic state by heating to a temperature at least 5° C. higher than the second article and then pressed to adhere to the adhesive coating on the second article. Method. 4. The first article is an attachment surface for a shoe tread member, and the second article is an attachment surface for a shoe upper;
3. The method of claim 2, wherein the coating is cooled to below the crystalline melting point of the urethane polymer prior to chain extension and the temperature of the chain extension steam is from about 32C to about 95C. 5 The first article is an attachment surface for a shoe tread member, and the second article is an attachment surface for a shoe upper;
4. The method of claim 3, wherein the volatile liquid is evaporated from the coating prior to chain extension and the temperature of the chain extension vapor is from about 32<0>C to about 95<0>C. 6. Process according to claim 4, characterized in that the prepolymer comprises a catalyst for the reaction of the prepolymer with the active hydrogen. 7. Process according to claim 5, characterized in that said prepolymer contains a catalyst for the reaction of said prepolymer with said active hydrogen. 8. The method of claim 4, wherein the adhesive on the surface of the second article is the same type of polyurethane as the polyurethane on the first article. 9. A method according to claim 5, characterized in that the adhesive on the surface of the second article is the same type of polyurethane as the polyurethane on the first article.