Adhesive polyurethane powder capable of being activated by heat

Abstract

A heat-activable powder adhesive composition for use in bonding a component to a surface such as glass is disclosed. The composition of the disclosed invention includes at least two polymers, at least one solid di- or poly-isocyanate in powder form, and a catalyst. Each of the two polymers has a melting point above 40° C. The two polymers are selected from the group consisting of di-functional polymers and multi-functional polymers. The preferred method of preparing the composition of the disclosed invention includes first forming three parts, including a first melted part comprising the polymers, a second melted part comprising the polymers and a catalyst, and a third part comprising the isocyanate. Once cooled, each of the first and second parts forms solid blocks which are fragmented and sieved. The three dry parts are then brought together to form the adhesive powder of the disclosed invention. The adhesive powder can be pre-applied to the attachment surface of a component to be bonded. The composition does not require either a deactivating agent or a blocking agent for deactivating the isocyanate or the catalyst nor does it require either a deactivated isocyanate or a deactivated catalyst.

Dependencies are inferred from the claim text.