Abstract: A polyester resin has excellent adhesiveness and excellent grindability. The polyester resin includes a constitutional unit A derived from a carboxylic acid having a cyclic structure and containing 5 or more carboxyl groups, a constitutional unit derived from a dicarboxylic acid, and a constitutional unit derived from a polyhydric alcohol. The constitutional unit A has a content of 0.01 parts by mole or more and 45 parts by mole or less with respect to 100 parts by mole of the constitutional unit derived from a dicarboxylic acid. The hydroxyl value of the polyester resin is 6 mgKOH/g or more and 27 mgKOH/g or less.

Abstract: The polyester resin of the present invention is a polyester resin obtained by using polyethylene terephthalate, a polyvalent carboxylic acid component, and a polyhydric alcohol component, wherein the polyester resin comprises 1 molar part or more in total of at least one type of structural unit selected from the group consisting of a structural unit derived from a tri- or higher valent carboxylic acid and a structural unit derived from a tri- or higher hydric alcohol, with respect to 100 molar parts of structural units derived from an acid component, and wherein a heat absorption is 0.1 to 10 J/g as measured with respect to the polyester resin heat-treated at 150° C. for 30 minutes.

Abstract: Provided is a polyester resin having excellent adhesiveness and excellent grindability. One aspect of the polyester resin of the present invention is a polyester resin including a constitutional unit A derived from a carboxylic acid having a cyclic structure and containing 5 or more carboxyl groups and a constitutional unit derived from a dicarboxylic acid, in which the constitutional unit A has a content of 0.01 parts by mole or more and 45 parts by mole or less with respect to 100 parts by mole of the constitutional unit derived from a dicarboxylic acid.