A kind of bifunctional polyester resin with good matting performance and its preparation method and application

Abstract

The invention discloses bifunctional polyester resin with good extinction performance and a preparation method and an application of the bifunctional polyester resin. The ifunctional polyester resin has acid value of 15-35 mgKOH / g, hydroxyl value of 20-60 mgKOH / g, melt viscosity at 200 DEG C of 4000-5500 mPa.s and glass transition temperature of 70-76 DEG C. The bifunctional polyester resin is prepared from diol, dibasic acid, a branching agent, an acidolysis agent and an esterification catalyst. The bifunctional polyester resin has higher glass transition temperature, good storage stability and proper properties such as hydroxyl value, acid value and viscosity. The preparation method of the bifunctional polyester resin is simple and efficient. The bifunctional polyester resin is applied to powder coatings, and coating films have good extinction performance and good board leveling performance, impact resistance and smooth and fine board hand feeling.

Description

technical field [0001] The invention relates to the field of polyester resins, in particular to a bifunctional polyester resin with good matting properties and a preparation method and application thereof. Background technique [0002] At present, the powder coatings are mainly high-gloss type, but as people gradually realize the harm of light pollution and the change of aesthetic concept, matte type powder coatings are more and more favored by users at home and abroad. [0003] The surface gloss of the coating film is selected according to the subjective and objective conditions such as the user's aesthetics and use requirements. The general gloss is divided into: more than 80% is called high gloss, 50% to 70% is called semi-gloss, and less than 10% is called semi-gloss. It is flat light, close to 0% is called dull. The outdoor matting powder coating with a gloss of 50% to 70% can generally be achieved by using the physical matting method filled with inorganic fillers. How...

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Problems solved by technology

The outdoor matting powder coating with a gloss of 50% to 70% can generally be achieved by using the physical matting method filled with inorganic fillers. However, since the density of the filler is more than 25% higher than that of the resin, it is necessary to destroy the flatness of the coating film and obtain a rough surface. Therefore, the leveling and mechanical properties of the coating prepared by this method are not good; the outdoor matting powder coating with a gloss of 20% to 40% is mainly dried by two polyester resins with different reactivity. Mixed matting, such as CN108148487A, which utilizes polyester resins with an acid value of 70-80 mgKOH / g and polyester resins with an acid value of 30-36 mgKOH / g for dry-blending matting, but on the one hand, dry-blending matting has a small gloss adjustable range, On the other hand, two different powder coatings need to be prepared separately and then dry-mixed, the production efficiency is low, and the production cost is also increased; the outdoor matting powder coating with a gloss of 10% to 20% is generally matted with a chemical matting agent; and When ordinary outdoor monofunctional polyester resins are used in the field of matting, it is difficult to achieve the matting gloss below 10%, and the matting gloss is unstable, the surface of the coating film is not leveled, not fine enough, and the mechanical properties are not good The problem

[0004] CN108084415A discloses that the acid value is 35-45mgKOH / g, the hydroxyl value is 10-25mgKOH / g, the glass transition temperature is 60-70°C, the melt viscosity at 200°C is 1000-5000mPa.s, and the number-average molecular mass is 2500-8000 The hydroxyl-terminated-carboxyl bifunctional saturated polyester resin, the bifunctional polyester resin has good leveling performance, impact resistance and transfer effect when used in powder coatings, but it can only achieve a gloss of 30o when compounded with a matting agent

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