Usm Corporation

Emhart Industries, Inc.

Hubertus Von Voithenberg

Heinz G Gilch

Karl-Heinz Albert

Raymond Hanson

Christopher M Allen

Gotz Hillert

Reinhard Rengel

Method of bonding a sole to a shoe by applying moisture-curable melt adhesive to the shoe upper, subjecting the adhesive coating to a hot-cure step with airborne moisture, and pressing the sole and shoe upper together with the adhesive between them immediately after the hot-cure step, preferably in less than 90 seconds after leaving the hot-cure. The bond is effected without application of adhesive to the sole, which is merely pre-treated by wiping with solvent or primer solution.

Attaching soles to shoes

Pressure-sensitive adhesives which are mixed immediately prior to application, or need drying equipment tend to be expensive in use while those applied as hot melts tend to have poor heat resistance. According to the invention an adhesive composition curable by atmospheric moisture is provided, the composition comprising a prepolymer component with isocyanate functionality between 2.0 and 3.0 together with one or more polyetherurethane prepolymers having NCO groups available for reaction with water for chain extension, the cured adhesive composition having a glass transition temperature below 20.degree. C.

Adhesive compositions

Novel, solvent free adhesive compositions comprising a moisture curable polyurethane formed from a first component comprising a diisocyanate, and a second component comprising a substantially linear hydroxy polyester in proportions to provide a prepolymer having from 1.0 to 2.0 percent by weight --NCO groups available for reaction, and a third component comprising a monofunctional reactant present in an amount sufficient to react with 1-40 mole % of the reactive --NCO groups of the product of the prepolymer reaction. A layer of applied adhesive may be exposed to airborne moisture under relatively mild conditions to bring about chain extension of the moisture curable polyurethane, after which the layer of the adhesive composition may be heated to bring it to tacky adhesive condition. The chain extended adhesive composition is storable for at least several days without affecting the bond strength.

Glue sticks for use in a hand held glue gun comprise thermoplastic coplyester corresponding to a product of an acid component comprising in selected proportions terephthalic acid, isophthalic acid and aliphatic dicarboxylic acid, an hydroxyl component comprising one or more aliphatic diols of which not less than 90 moles % is 1.4 butane diol, and a polymeric plasticizer component. The glue stick has a melting point of 90.degree. to 120.degree. C. and a reduced viscosity of 0.5 to 0.7. Preferred glue sticks have a melting point of about 110.degree. C., a reduced viscosity of 0.6 to 0.65 and comprise a copolyester from an acid component comprising 45 to 48 moles % terephthalic acid, 38 to 45 moles % isophthalic acid and 10 to 15 moles % azelaic acid, an hydroxyl component comprising 1.4 butane diol and 1.6 hexane diol in a molar ratio of 90 to 95:5 to 10, and a polymeric plasticizer component comprising a polycaprolactone or selected hydroxy polyester to an extent of 3 to 4% by weight of the copolyester. The glue sticks can be used as general purpose adhesives and have useful open times.

Growing community of inventors

Bad Homburg, Germany

Hubertus Von Voithenberg