Adhesive composition
AssigneeE. I. Du Pont de Nemours and Company
InventorJudith W. Becker
Life of this patent
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Abstract
A polyurethane adhesive, suitable for bonding of shoe uppers to shoe soles, is based on an isocyanateterminated prepolymer made from tolylene diisocyanate, a poly(tetramethyleneoxy) glycol, and a poly(ethyleneoxy) compound having 7-30 ethyleneoxy groups and 1 or 2 hydroxyl groups. This prepolymer can be cured with a mixture of a methylenedianiline/sodium chloride complex with urea at a temperature of 70.degree. C, which is safe for the usual shoe materials. Adhesive compositions containing both the prepolymer and the curing agent have at room temperature a potlife of at least 24 hours.
Claims11
A curable polyurethane prepolymer made by a reaction of 1.2-2.0 moles of tolylene diisocyanate containing at least 65% of the 2,4-isomer with 1 mole of poly(tetramethyleneoxy) glycol having a number average molecular weight of about 400-3000, and a poly(ethyleneoxy) compound having a number average molecular weight of about 310-4000 and containing 7-30 (--CH.sub.2 --Ch.sub.2 O--) groups and 1 or 2 hydroxyl groups, its (--CH.sub.2 --CH.sub.2 O--) groups providing 0.5-4.0% of the combined weight of the poly(ethyleneoxy) compound and poly(tetramethyleneoxy) glycol, while the poly(tetramethyleneoxy) glycol provides no less than 80% of said combined weight.
Dependencies are inferred from the claim text.