A kind of polyester resin for tgic curing matting powder coating and preparation method thereof

Abstract

The invention discloses polyester resin for TGIC (triglycidyl isocyanurate) curing and matting powder coatings, and a preparation method and application thereof. The acid value of the polyester resinis 28-36mgKOH / g, the glass transition temperature is 55-68 DEG C, and the melt viscosity is 200-6000mPa.s at the temperature of 200 DEG C; the polyester resin is prepared from the following raw materials in percentage by mass: 30-46% of polyol, 0.5-6% of cyclobutanediol, 45-65% of polybasic acid, 1-10% of aromatic acidolysis agents, 0.5-3% of aliphatic acidolysis agents, 0.05-0.25% of esterification catalyst, 0.01-0.2% of curing accelerator and 0.2-1.2% of antioxidants. The TGIC-system matting powder coatings prepared from the polyester resin have the gloss of 10-15%, 50cm positive and negative impact tests of the coatings are qualified, and no powder agglomeration is found during storage; the TGIC-system matting powder coatings have better matting effect, higher impact resistance and higher powder storage stability than existing TGIC-system matting powder coatings, and the cost is reduced to some extent by use of the one-component polyester resin.

Description

Technical field [0001] The invention relates to the technical field of polyester resins, in particular to a polyester resin for TGIC curing matting powder coatings and a preparation method thereof. Background technique [0002] At present, powder coatings are widely used in outdoor applications, and their varieties are constantly increasing. Generally speaking, noble and luxurious decoration requires high gloss, while quiet, comfortable and elegant environment requires lower gloss. However, high-gloss coating will cause serious light pollution and damage the eyes. In addition, consumers' aesthetic concepts are also changing, and they are more inclined to a casual and comfortable living environment. Therefore, matting powder coatings that can produce soft surface effects are more and more widely used. According to statistics, the amount of semi-gloss and matte powder coatings has exceeded 30% of the total amount of indoor and outdoor powder coatings. [0003] CN102190786A disclose...

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Problems solved by technology

[0003] CN102190786A discloses a polyester resin with an acid value of 30-80 mgKOH / g. When it is applied to an epoxy powder coating system, the gloss of the powder coating is 11-25% (60°); CN104448273A discloses an acid value of 65 ~ 80mgKOH / g, glass transition temperature of 59.4 ~ 69.7 ℃, 165 ℃ melt viscosity of 13500 ~ 35000mPa s indoor matting saturated polyester resin, when it is applied to the epoxy powder coating system, the powder coating The glossiness is 5-30% (60°); CN104558561A discloses an indoor-type matting powder coating special-purpose low-grade paint with an acid value of 19-23mgKOH / g, a viscosity of 5-7Pa·s at 200°C, and a softening point of 110-115°C. Acid value saturated polyester resin, when it is applied to epoxy powder coating system, the glossiness of this powder coating is 2~70% (60 °); CN105860047A discloses the use of purified terephthalic acid, neopentyl glycol, ethylene Polyester resin with an acid value of 68-75mgKOH / g, a glass transition temperature of 58-65°C, and a softening point of 108-115°C prepared by alcohol, adipic acid, trimellitic anhydride, and polyester modified enzymes. The resin itself has extinction When it is applied to the epoxy powder coating system, the gloss of the powder coating is 7-9% (60°). Although the powder coating prepared by the above-mentioned polyester resin can achieve a good matting effect to a certain extent, However, the above polyester resins are only used in epoxy powder systems, and the prepared powder coatings have poor weather resistance and are not suitable for outdoor environments.

[0004] At present, there is a huge market demand for polyester used in outdoor matting powder coatings in China, and TGIC system matting powder coatings account for more than half of the outdoor matting powder coatings. However, TGIC system matting powder coatings made of polyester generally have the following defects on the market : the impact resistance of the prepared matting powder coating is relatively poor, and cracking phenomenon often occurs when the reverse impact is 50cm; the paint coating is difficult to matt, and a large amount of expensive matting agent needs to be added to realize glossiness below 15% (60°); storage stability is poor , the powder storage process is prone to agglomeration. If you choose to use polyester with a high glass transition temperature, although the storage stability can be improved, but at the same time, poor coating appearance such as orange peel will appear.

[0005] At present, the research on the TGIC system matting powder coating mainly focuses on the two-component dry-mixing matting system, and CN108148487A discloses the TGIC system matting powder coating of two component powders of fast and slow (high and low acid value polyester resins), but its Glossiness is 20~23%, and CN106046711A discloses the polyester resin composition that the heat-transfer powder coating of dry mix matting type is used, comprises high acid value polyester resin (acid value 47~55mgKOH / g, melt viscosity 7000 ~10000mPa·s, glass transition temperature 63~71℃, 180℃ reactivity 50~200s) and low acid value polyester resin (acid value 18~24mgKOH / g, melt viscosity 4000~9000mPa s, glass Transition temperature is 58~68°C, 180°C reactivity is 300~600s), its gloss in TGIC system is 15~40%; CN103131308A also discloses high and low acid value two-component carboxy-terminated polyester resin composition, Its glossiness in TGIC system is 18~45%, there are following problems for the TGIC system extinction powder coating prepared by the method for above-mentioned two-component dry mixing: glossiness is difficult to realize below 15% (60 °); Poor; two polyester resins with acid values ​​need to be prepared, the operation is cumbersome and the cost is high

[0006] There are few relevant reports on polyester resins for one-component TGIC system matting powder coatings

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