PROCESS FOR PRODUCING URETHANE RESIN AND PRESSURE-SENSITIVE ADHESIVE

摘要

A process for producing a urethane resin which has a low viscosity and is usable as a wide range of pressure-sensitive adhesives ranging from highly tacky ones to extremely lowly tacky ones; and a pressure-sensitive adhesive. The process for urethane resin production comprises reacting a polyol with a polyisocyanate compound in an isocyanate-group-excess proportion to obtain an isocyanate-terminated prepolymer and then reacting the isocyanate-terminated prepolymer with a chain extender and subsequently with a chain terminator, and is characterized in that the chain extender has three or more functional groups reactive with an isocyanate group, provided that one of these functional groups is a primary amino or secondary amino group, another is a primary hydroxy group, and the remaining functional group(s) are secondary hydroxy or tertiary hydroxy groups. The pressure-sensitive adhesive comprises the urethane resin obtained.