POLYESTERS, POLYESTER COMPOSITIONS, PRESSURE-SENSITIVE ADHESIVE COMPOSITIONS, PRESSURE-SENSITIVE ADHESIVE LAYERS AND PRESSURE-SENSITIVE ADHESIVE SHEETS

摘要

The present invention provides a polyester, a polyester composition and a pressure-sensitive adhesive composition capable of obtaining a pressure-sensitive adhesive which is global-environmentally friendly and is excellent in pressure-sensitive adhesion properties, using a plant-derived raw material; and a pressure-sensitive adhesive layer and a pressure-sensitive adhesive sheet which can be obtained by using the same. A polyester of the present invention is a polyester comprising at least a lactic acid unit, a dibasic acid unit and a glycol unit, wherein the dibasic acid unit contains dimer acid, and the polyester has a glass transition temperature as measured at a temperature rising rate of 20° C./minute using a differential scanning calorimeter, of −70 to −20° C., a weight average molecular weight of 20,000 to 300,000 and a hydroxyl value of 1 to 100 mgKOH/g.