GB1115251A - Improvements in or relating to attaching heels to shoes - Google Patents

Abstract

1,115,251. Boots &c. BRITISH UNITED SHOE MACHINERY CO. Ltd. 30 June, 1965 [1 July, 1964; 22 Jan., 4965], No. 27618/65. Heading A3B. A heel H of plastics material is attached to a shoe upper A by applying a polyurethane adhesive in fluid, foamable reactive state and an organic solvent capable of dissolving the plastics material of the heel, to the heel seat portion of the heel and maintaining the heel in position on the shoe upper while the adhesive is reacting to provide a stiffened, foamed polyurethane bond between the heel and the shoe upper. The organic solvent may be applied to the heel before the polyurethane adhesive is applied or may be applied in admixture with the polyurethane adhesive. The heel may be held in position while the adhesive is reacting by a screw applied by a -screw inserting means D of the type described in Specification No.607,345. The adhesive is applied to the heel by an attachment to the screw inserting machine. Adhesive is stored in a plastic container inside a box B, the container having a flexible outlet tube 20 which is housed in a tubular guide 16 having a slot 18. Adhesive is squeezed -from the tube 20 on to the heel by a roller 34 which is pressed against the tube 20 by a roller on the piston rod of pneumatic cylinder 42 and is moved downwardly by the piston rod 30 of pneumatic cylinder 28. The polyurethane adhesive is produced by the reaction of a polyisocyanate with a polyhydric alcohol, a polyester polyol or a polyether polyol, there being an excess of free or unreacted isocyanate groups which will react with moisture to cause the adhesive to expand. Preferably the adhesive is the reaction product of polyethylene glycol and polymethylene polyphenylisocyanate. The adhesive may also include extenders and fillers such as sulphur, ground cork, clay, glass fibres, wood pulp, foam glass, gypsum, aluminium silicates or hydroxides or synthetic polymers such as polyvinyl chloride or polystyrene. Suitable solvents capable of dissolving the plastics material of the heel are aromatic hydrocarbons such as toluene, xylene, cumene, chlorinated hydrocarbons such as ethylene chloride, ethyl benzine, chlorobenzine, ethylene dichloride, carbontetrachloride, chloroform, benzyl chloride, chlorotoluene, as well as n-butyl acetate, cellosolve acetate, dimethyl foramide. When the heel is made of acrylonitrile-butadiene-styrene copolymer the solvent is preferably ethylene dichloride.