Polyester resin for epoxy resin-cured precoated anticorrosive powder coating and preparation method thereof

Abstract

The invention discloses polyester resin for epoxy resin-cured precoated anticorrosive powder coating. The polyester resin comprises the following components in percent by mass: 30-50% of polyalcohol, 5-35% of furan dicarboxylic acid, 5-25% of naphthalic acid, 5-40% of polyacid, 5-20% of an acidolysis agent, 0.04-0.15% of a catalyst and 0.01-1.0% of a curing accelerant; melt polymerization is performed on the components to obtain the polyester resin with the acid value of 65-100mgKOH/g, the viscosity of 2500-5000mPa.s, the number average molecular weight of 2000-4000 and the glass transition temperature of 55-75 DEGC. The invention further discloses a preparation method of the polyester resin. The polyester resin contains cyclic ether and naphthalene ring structures, and has excellent corrosion resistance, bending resistance and other properties; after being cured by epoxy resin E-12, the polyester resin is particularly suitable for the precoated anticorrosive powder coating; the prepared powder coating is fully applicable to a process flow of an anti-corrosive component which is coated first and then moulded, and other requirements; the conventional processing efficiency can be greatly improved; a coating film is high in hardness and outstanding in toughness.

Description

technical field [0001] The invention relates to a polyester resin and a preparation method thereof, in particular to a polyester resin for epoxy resin curing precoat anticorrosion powder coating and a preparation method thereof. Background technique [0002] Powder coatings are gradually replacing organic solvent-based coatings due to their advantages of economy, environmental protection, high efficiency and excellent performance, and have become an important development direction in the coatings industry, especially polyester-based powder coatings. The outstanding advantages in terms of efficiency, economy and mechanical properties have already occupied half of the entire powder coating system. With the rapid development of my country's shipbuilding industry, national defense industry, and energy, the application of heavy-duty anti-corrosion powder coatings has become more and more extensive, and higher requirements have also been put forward. [0003] However, usually pol...

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Problems solved by technology

[0006] As mentioned above, although there are reports on the synthetic technology of polyester resins for anti-corrosion powder coatings in the prior art, the technical problem solved is only to improve the anti-corrosion properties of polyester by improving the selection of polyols in raw materials, and there is still no research on anti-corrosion powder coatings. The optimization and improvement reports of other properties, and there is no report that it can be used on pre-coated powder coatings, which is different from the starting point of the patent application of the present invention

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