Polyester binder resin for coating and coating composition containing same

摘要

Disclosed are a polyester binder resin for coating which is copolymerized with lactic acid or a compound derived therefrom and isosorbide, and thus has a high content of biomass-derived compounds, and exhibits superior coating hardness, contamination resistance, hydrolytic resistance, processability and the like, and a coating composition comprising the same. The polyester resin binder for coating is copolymerized with a diacid component, a diol component comprising 1 to 60 moles of isosorbide, with respect to a total diol component, and 1 to 50% by weight of lactic acid or a compound derived therefrom, with respect to the total amount of resin polymerization reactants, wherein the polyester resin binder for coating has a structure in which a diacid moiety derived from the diacid component, a diol moiety derived from the diol component, and a hydroxyl monoacid moiety derived from the lactic acid or a compound derived therefrom are repeated.

主权项

1. A polyester resin binder for coating, copolymerized with
a diacid component comprising 70 to 100 mol % of terephthalic acid, isophthalic acid, and mixtures thereof, a diol component comprising 10 to 55 mol % of isosorbide, with respect to a total diol component, and 1 to 50% by weight of lactic acid or a compound derived therefrom, with respect to the total amount of resin polymerization reactants, wherein the polyester resin binder for coating has a structure in which a diacid moiety derived from the diacid component, a diol moiety derived from the diol component, and a hydroxyl monoacid moiety derived from the lactic acid or a compound derived therefrom are repeated, wherein the polyester resin binder has a glass transition temperature (Tg) of 80 to 150° C., wherein the diol component further comprises 45 to 90 mol % of glycol selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, propanediol, 1,4-butanediol, pentanediol, hexanediol, neopentyl glycol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tetramethyl cyclobutanediol, and mixtures thereof.