Claims
- 1. A method of bonding a PVC, thermoplastic rubber or polyurethane shoe sole to a shoe upper which consists of:
- pretreating the PVC, thermoplastic rubber or polyurethane sole by wiping with a solvent or primer solution;
- applying a fast-curing moisture-curable hot melt adhesive to the shoe upper;
- immediately after the application of said adhesive, subjecting the adhesive to a hot-cure step with airborne moisture for a time of from about 30 to about 120 seconds at a temperature of about 100.degree. C. to about 110.degree. C. and a relative humidity of less than 30%; and
- pressing the shoe upper and the sole together with the adhesive between them in less than immediately after the shoe upper has left the hot-cure step.
- 2. The method of claim 1 wherein the moisture curable adhesive is applied to the shoe upper as a thin film of 0.1-0.3mm.
Priority Claims (1)
| Number |
Date |
Country |
Kind |
| 8615062 |
Jun 1986 |
GBX |
|
BACKGROUND OF THE INVENTION 1. Field of the Invention
This is a continuation of co-pending application Ser. No. 930,604 filed on Nov. 12, 1986, now abandoned.
The present invention relates to the attaching of soles to shoes using moisture-curable melt-adhesives. 2. Description of the Prior Art
So-called "two-way cementing systems" are well known in the shoe industry in which adhesive is applied to the contact surface of a sole and to the contact surface of a shoe bottom and creating a bond by bringing the contact surfaces of sole and of shoe bottom together under pressure.
The efficiency of such processes may be measured both in the performance of the product (the shoe) and in the demands of time, cost, space, safety, etc. of the manufacturing operation.
Neoprene-based adhesives provided satisfactory results with two-way cementing systems but, being solvent-based, present new problems related to solvent removal, including general environmental disadvantages and undesirable working conditions.
Polyurethane-based adhesives when used initially, although inherently compatible with a wider range of materials, were still solvent-based but with somewhat reduced levels of solvent-removal difficulties.
In U.K. patent specification GB No. 2,137,638 is described and claimed a so-called solvent-free adhesive which is a moisture-curable composition comprising polyurethane pre-polymers and its use in bonding a sole to a shoe upper is also claimed.
The method of GB No. 2,137,638 for bonding a sole to a shoe upper comprised the steps of providing on attaching surfaces of one or both of the sole and shoe upper a layer of adhesive composition, exposing each layer of adhesive composition of air-borne moisture to bring chain extension of the polyurethane, heating the layer or at least one of the layers of the adhesive composition to bring it to tacky adhesive condition, pressing the attaching surfaces of the sole and upper together with the composition between them and bringing about cooling of the composition to form an adhesive bond between the sole and the shoe upper. That is to say, this process required a step of heating at least one layer of adhesive to bring it to tacky adhesive condition (activation) before pressing sole and upper together to form an adhesive bond.
It is an object of the present invention to provide an improved method of bonding a sole to a shoe using a moisture-curable melt adhesive.
According to the present invention, we provide a method of bonding a sole to a shoe in which a moisture-curable melt adhesive is applied to either the sole and/or shoe upper, the adhesive coating is subjected to a hot-cure step with air-borne moisture, and the sole and shoe upper are pressed together with the adhesive between them, characterised in that the pressing takes place immediately after the hot-cure step, preferably in less than 90 seconds after leaving the hot-cure.
US Referenced Citations (3)
| Number |
Name |
Date |
Kind |
| 3116501 |
Markevitch |
Jan 1964 |
|
| 4156064 |
Falkenstein et al. |
May 1979 |
|
| 4618651 |
Gilch et al. |
Oct 1986 |
|
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| Number |
Date |
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| 0043645 |
Jan 1982 |
EPX |
| 0092320 |
Oct 1983 |
EPX |
| 0125008 |
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EPX |
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Nov 1984 |
EPX |
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Continuations (1)
|
Number |
Date |
Country |
| Parent |
930604 |
Nov 1986 |
|
Patent Grant
4846919
