Epoxy resin for high-gloss self-curing powder coating and two-pot preparation method

Abstract

The invention belongs to the technical field of paint raw materials, and in particular relates to an epoxy resin for high-gloss self-curing powder paint and a method for combining the same with two kettles. The epoxy resin for high-gloss self-curing powder coatings provided by the present invention, the main raw materials are bisphenol A, 1,10-sebacic acid, epichlorohydrin, sodium hydroxide, trimellitic acid, n-butanol, Adipic acid, terephthalic acid, diethylene glycol, glyceryl monoisostearate, triglycidyl isocyanurate; the epoxy resin is prepared from the above main raw materials through polymerization. The present invention prepares the epoxy resin with both carboxyl-termination and epoxy-termination by means of the double-pot joint process, and fully mixing in the molten state can ensure that the epoxy resin product that finally participates in curing is in a uniformly dispersed state, realizing the same Batches of powder coatings have better stability, overcome the problem of uneven curing caused by different activities, and the coating film performance fully meets the conventional requirements of powder coatings.

Description

technical field [0001] The invention belongs to the technical field of paint raw materials, and in particular relates to an epoxy resin for high-gloss self-curing powder coatings; it also relates to the above-mentioned method for combining epoxy resin with two kettles. Background technique [0002] At present, if epoxy resin powder coatings are to be formed into films, they are generally cured with polyester resins or curing agents such as 2-phenylimidazole, dicyandiamide, etc., but there are still the following deficiencies: [0003] (1) Physical mixing of polyester resin or curing agent and granular epoxy resin is difficult to fully mix evenly. Subsequent extrusion mixing with twin-screw extruder is prone to uneven dispersion, resulting in the final powder coating. The uneven distribution of epoxy resin and curing agent or polyester resin often leads to the problem of large differences in curing effect of the same batch of powder coatings; [0004] (2) Due to the high act...

AI Technical Summary

Problems solved by technology

[0003] (1) Physical mixing of polyester resin or curing agent and granular epoxy resin is difficult to fully mix evenly. Subsequent extrusion mixing with twin-screw extruder is prone to uneven dispersion, resulting in the final powder coating. The uneven distribution of epoxy resin and curing agent or polyester resin often leads to the problem of large differences in curing effect of the same batch of powder coatings;

[0004] (2) Due to the high activity of curing agents such as 2-phenylimidazole and dicyandiamide, and the poor compatibility between epoxy resin and polyester resin, the curing speed is not uniform at high temperature, which makes it difficult to realize the conventional powder coating formula High Gloss Requirements

The obvious common features of the above methods are: firstly, the premixing time is relatively long to ensure that the physical mixing is sufficiently uniform, and generally it is necessary to mix at a high speed in a high-speed mixer for more than 30 minutes; in addition, twin-screw extrusion and The extrusion time is longer (the length of the screw should be longer) to ensure its good miscibility. Generally, the twin-screw extrusion process takes more than 30 minutes, and due to the miscibility problem, batch curing differences are prone to occur in production, and curing occurs. Powder coatings with poor properties need to be extruded again with twin-screw extruders to obtain qualified products, resulting in low production efficiency, and these products have high requirements for extrusion equipment, and some customers’ single-screw extruders are difficult to prepare qualified products

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