Tin-free hydroxyl polyester resin for hot-water-resistant powder coating and preparation method of hydroxyl polyester resin

Abstract

The invention discloses hydroxyl polyester resin for a tin-free hot-water-resistant powder coating and a preparation method of the hydroxyl polyester resin. The hydroxyl polyester resin is prepared from the following main components in percentage by weight through esterification, pre-polycondensation and final polycondensation reaction: 0.8-3.0% of a catalyst; a polyol: 28.0 to 53.0%; a polybasic acid: 30.0 to 50.0%; the catalyst is ethylene glycol titanium, and the polybasic acid is 2, 3, 3 ', 4'-biphenyl tetracarboxylic dianhydride or 2, 3, 3 ', 4'-diphenyl ether tetracarboxylic dianhydride, terephthalic acid and isophthalic acid. The hydroxyl value of the hydroxyl polyester resin for the tin-free hot-water-resistant powder coating prepared by the preparation method disclosed by the invention is 25.0-35.0 mgKOH / g, and the polyester resin with a low hydroxyl value consumes less curing agent and is high in cost performance in production and manufacturing of the powder coating; the glass transition temperature is 74.0-80.0 DEG C. The powder coating prepared from the resin with high glass transition temperature is not easy to cake and has good storage stability; and the viscosity is 180.0-220.0 Pa.s / 200 DEG C. The powder coating prepared from the high-viscosity polyester resin has good mechanical properties, and has the characteristics of no tin, good hot water resistance, good mechanical properties, high hardness and the like.

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