All-polyester resin for HAA curable coil powder coating and preparation method thereof

Abstract

The invention discloses all-polyester resin for an HAA curable coil powder coating. The all-polyester resin is end-carboxyl saturated polyester resin, the average functionality is 1.85-1.95, the acid value is 68-74 mg KOH / g, the glass-transition temperature is 60-65 DEG C, the softening point is 102-108 DEG C, the 200 DEG C melt viscosity is 3000-6000 Pa.s, and the 180 DEG C reactivity is 60-100 s. The all-polyester resin is prepared from, by mass, 30-35% of dihydric alcohol, 52-63% of aromatic dibasic acid, 1.8-11.5% of aliphatic dibasic acid and 1.5-3.0% of polyhydric alcohol, wherein the monomer components are subjected to melt phase polycondensation to prepare the all-polyester resin. The invention further discloses a preparation method of the polyester resin. The polyester resin has high reaction activity and short curing time and is suitable for a fast curing system required by the coil coating, and the powder coating prepared from the polyester resin is excellent in overall performance and has good hardness, flexibility, weather resistance, chemical resistance, solvent resistance, corrosion resistance, adhesiveness, impact resistance and the like after being cured for 60 s at 280 DEG C.

Description

technical field [0001] The invention relates to a polyester resin, in particular to a pure polyester resin for HAA cured coil powder coating, and simultaneously the invention also relates to a preparation method of the polyester resin. Background technique [0002] The coating of coil steel is a pre-coating method, which is different from the traditional "post-coating". Due to a series of advantages such as simplified production process, efficient construction, saving investment and operating costs, compliance with environmental protection regulations, and better performance than traditional methods, it is a development direction of the coatings industry in the future, whether in the field of paint or other types of coatings. As we all know, traditional liquid coil coatings were successfully developed and applied in the late 1950s and early 1960s. To date, almost all prepainted coil coatings have been painted using liquid coil coatings. However, because liquid coil coating...

AI Technical Summary

Problems solved by technology

Generally speaking, conventional polyester powder coatings generally need to be baked at 180°C to 210°C for 10 to 20 minutes before they can be fully cured. When the curing temperature is raised to about 270°C and the curing time is shortened to tens of seconds, the coating The film will be incompletely cured, resulting in poor impact resistance, poor adhesion, poor bending performance and insufficient weather resistance of the coating.

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