High-gloss self-curing type epoxy resin for powder coating and double-kettle preparation method

An epoxy resin and powder coating technology, applied in powder coatings, epoxy resin coatings, polyester coatings, etc., can solve the problems of uneven dispersion, batch curing differences, long premixing time, etc., and meet the requirements of miscibility Low, good stability, high gloss effect

Active Publication Date: 2020-02-21
HUANGSHAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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

Method used

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  • High-gloss self-curing type epoxy resin for powder coating and double-kettle preparation method
  • High-gloss self-curing type epoxy resin for powder coating and double-kettle preparation method
  • High-gloss self-curing type epoxy resin for powder coating and double-kettle preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] Prepare the main raw materials in the following mole fractions:

[0053] Bisphenol A 5mol; 1,10-sebacic acid 7mol; epichlorohydrin 12mol; sodium hydroxide 15mol; monobutyl trimellitic acid 8mol; adipic acid 10mol; terephthalic acid 12mol; diethylene glycol 13mol; 8 mol of glyceryl isostearate; 6 mol of triglycidyl isocyanurate; the following method is carried out according to the above-mentioned amount of raw materials.

[0054] A double-pot preparation method for epoxy resin for high-gloss self-curing powder coatings, comprising the following steps:

[0055] (1) Dissolve sodium hydroxide in water to prepare a sodium hydroxide solution with a mass concentration of 40%, then add it to the first reaction kettle, and heat up to 50°C, then add bisphenol A, 1,10-decanedi Acid and the first catalyst, heat up to 60°C and keep it warm for 2 hours. When the pH reaches about 9.5, start adding epichlorohydrin dropwise. The dropwise addition is completed within 2 hours. Keep it at...

Embodiment 2

[0063] The consumption of each raw material among embodiment 2 and embodiment 4 is different from embodiment 1, specifically as follows:

[0064] The consumption (mol) of each raw material in table 1 embodiment 1~4

[0065]

[0066]

Embodiment 5

[0085] Embodiments 1 to 4 Grades Comparative Examples 1 to 5 adopt the following powder coating formula, and the formula is usually as follows in parts by weight:

[0086]

[0087] Preparation of powder coating: according to the formula of the above powder coating, all materials are mixed evenly, extruded rapidly (within 5min) with a single-screw extruder, pressed into tablets, crushed, and then the flakes are crushed and sieved to make a powder coating (160 -200 mesh). The powder coating is sprayed on the surface-treated tinplate substrate with an electrostatic spray gun, and cured at 180°C / 15min to obtain the coating.

[0088] Comparative Example 6 and Comparative Example 7 use finished powder coatings for performance comparison without additional preparation of powder coatings.

[0089] performance comparison

[0090] The test method of epoxy equivalent is based on GB / T 4612-2008 "Determination of epoxy equivalent of plastic epoxy compounds"

[0091] Coating index tes...

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Abstract

The invention belongs to the technical field of coating raw materials, and specifically relates to high-gloss self-curing type epoxy resin for a powder coating and a double-kettle combined method forthe epoxy resin. The high-gloss self-curing type epoxy resin for the powder coating provided by the invention comprises the following main raw materials: bisphenol A, 1,10-sebacic acid, epoxy chloropropane, sodium hydroxide, trimellitic acid, n-butyl alcohol, adipic acid, terephthalic acid, diethylene glycol, glyceryl monoisostearate and triglycidyl isocyanurate. The epoxy resin is prepared from the above-mentioned main raw materials through a polymerization reaction. According to the invention, the epoxy resin with terminated carboxyl group and terminated epoxy group is prepared by virtue ofa double-kettle combined process; the epoxy resin is fully mixed in a molten state; an epoxy resin product finally participating in curing can be guaranteed to be in a uniformly dispersed state; thus,the powder coating in a same batch has better stability; the problem of non-uniform curing caused by different activities is solved; and the coating performance completely meets the conventional requirements of the powder coating.

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...

Claims

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Application Information

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IPC IPC(8): C08G59/06C08G59/14C08G63/672C08G63/78C09D5/03C09D163/00C09D167/02
CPCC08G59/063C08G59/1438C08G63/672C08G63/78C09D163/00C09D167/02C09D5/03C08L67/02C08L63/00
Inventor 王永垒李海云江蓉魏文静孙继影孙巧巧王景
Owner HUANGSHAN UNIV
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