Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Patent
1985-07-12
1987-11-10
Weston, Caleb
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
156245, 1562722, 264244, 8 9419R, 8 9420, 8 9422, 8 9423, 81505, 12142R, 12142T, 427389, 427412, 428473, 428904, B32B 3124
Patent
active
047055863
DESCRIPTION:
BRIEF SUMMARY
The invention relates to working leather, more particularly for fabricating footwear uppers.
A very great deal of footwear is manufactured by assembling an upper to a sole. To perform this assembly, the upper is placed on a last which has a face adjacent to the margin of the upper which constitutes one wall of a mold cavity into which plastics material is injected to constitute the sole, which is thus fixed to the margin of the upper during the molding operation. Alternatively, a layer of glue is applied to the margin of the upper while on the last, and a sole of leather or plastic is applied thereto and is thus fixed to the upper by gluing or by bonding.
When the uppers are made of leather, the shoe manufacturer receives hides from a tanner and cuts up the hides into uppers. However, before delivering hides, the tanner treats them by applying a layer of finish as requested by the manufacturer to give the leather a final appearance desired for the upper from the point of view of color and/or surface state.
Having observed that, all too often the sole adheres inadequately to an upper coming from a leather treated in this manner, and having determined that this fault stems from poor bonding between the layer of finish and the hide, shoe manufacturers have taken the habit, prior to assembly, of removing the layer of finish from the margin of the upper where it is intended to come into contact with the sole. This is usually done by sanding or by carding.
However, it very frequently happens that the carded or sanded margin does not coincide with the portion of the upper which will subsequently come into contact with the sole. If the sanded or carded margin is too wide, the finished shoe will have a more or less regular finish-free border. This gap needs to be retouched by hand, which is expensive. In contrast, if the margin is too narrow the sole will have inadequate adhesion to the non-sanded or non-carded border, and all too often the shoes will have to be rejected. In all cases, adhesion between the upper and the sole is limited to the portion of the surface which has been sanded or carded.
The invention provides a method which goes against previous proposals of removing material applied to the hide prior to fixing to the sole: instead a deposit is applied thereto suitable for obtaining the desired final result, e.g. ensuring that the leather finished in this manner adheres to a sole at least as well as does leather which has had all such products removed by sanding or carding.
The method is particularly of interest for manufacturing sports shoes such as jogging or training shoes in which the leather constituting the uppers must be pale or even white in color, thus making irregularities due to sanding or carding unacceptable, particularly when the sole includes a peripheral flange for partially covering the upper.
According to the present invention, a deposit of material adhering to the leather is formed on the surface of the leather to enable a leather footwear upper treated in this way to adhere to a sole without being carded or sanded, either by direct injection of sole-constituting material, or else by bonding on or by gluing on a prefabricated sole.
The footwear manufacturer thus has no preliminary operations to perform on the leather as delivered by the tanner after being subjected to the surface treatment of the invention. Furthermore, the surface treatment does not imply increased tanning costs, since it replaces the finishing operations that were previously necessary to provide leather with the surface appearance and mechanical properties desired by the footwear manufacturer.
The sanding or carding step previously required when fitting soles is thus avoided, as are manufacturing rejects and also the need for retouching, while retaining versatility concerning the designs of footwear which can be manufactured.
According to a particular mode of implementing the invention, the deposit is formed on the surface of the leather by a plurality of superposed layers, each of which is chosen to adhere to the un
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patent: 2828224 (1958-03-01), Alps et al.
patent: 3178310 (1965-04-01), Berger et al.
patent: 3245827 (1966-04-01), Weber
patent: 3298856 (1967-01-01), Harding
patent: 3761304 (1973-09-01), Hansson
patent: 4256809 (1981-03-01), Larsson et al.
de Mauduit Yves
Lipovac Vincent
Pouget Jacques
Borden Inc.
Weston Caleb
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