Ultra-weatherproof carboxyl-terminated fluorine-containing polyester resin for powder coating and preparation method of ultra-weatherproof carboxyl-terminated fluorine-containing polyester resin

Abstract

The invention provides an ultra-weatherproof carboxyl-terminated fluorine-containing polyester resin for a powder coating and a preparation method of the ultra-weatherproof carboxyl-terminated fluorine-containing polyester resin. The acid value of the fluorine-containing polyester resin prepared in the method is 23 to 35 mg KOH in every gram of resin, the hydroxyl value is smaller than 10 mg KOH in every gram of resin, the glass-transition temperature is 55 to 75 DEG C, the melt viscosity is 2000 to 22000 mPa.s per 200 DEG C, the number-average molecular weight is 2500 to 8000, and the fluorine content is 1% to 5% continuously adjustable. The ultra-weatherproof carboxyl-terminated fluorine-containing polyester resin has the advantages of appropriate glass-transition temperature, simple resin synthetic process, low cost and the like, and the powder coating prepared through curing of triglycidyl isocyanurate or hydroxyl alkyl amide has the advantages of ultra-weatherproof performance, high glossiness, excellent leveling, high impact property and the like.

Description

technical field [0001] The invention belongs to the field of coating resins, in particular to a super-weather-resistant carboxyl-terminated fluorine-containing polyester resin for powder coatings and a preparation method thereof. Background technique [0002] Polyester powder coating for outdoor use is a widely used thermosetting coating, which currently accounts for about 70% of the total output of powder coatings. It has the advantages of energy saving, environmental friendliness, long service life and excellent performance. It is widely used in various outdoor The coating of the surface of parts. [0003] As the powder coating market expands, people are increasingly demanding weather resistance. For example, the secondary coating of aluminum profiles for high-rise buildings and sea-crossing bridges is very difficult during the service life, so super weather-resistant powder coatings are generally selected to avoid frequent secondary coating. Therefore, further expanding...

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Problems solved by technology

For example, Chinese patent CN201510009803.8 "Polyester resin for super weather-resistant powder coating, powder coating using the resin and its preparation method" by adding tetrafluoroisophthalic acid, hexafluoroglutaric acid and 1H, 1H in the synthesis process, 10H, 10H-perfluoro-1,10-decanediol improves weather resistance, but tetrafluoroisophthalic acid, hexafluoroglutaric acid and 1H, 1H, 10H, 10H-perfluoro-1,10-decanediol Diols are very expensive and cannot be industrialized

[0007] Chinese patent CN200910184341.8 "a super-weather-resistant powder coating and its preparation method and application" discloses the preparation of super-weather-resistant powder coatings by extruding and blending conventional weather-resistant polyester resins and FEVE fluorocarbon resins. However, due to the poor compatibility of the mixed system prepared by extrusion, the system has defects such as low gloss and poor impact performance, which is also unfavorable for market promotion.

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