Epoxy resin for high-hardness and low-temperature curing type powder coating and preparation method

A technology of epoxy resin and powder coatings, which is applied in powder coatings, epoxy resin coatings, fireproof coatings, etc., and can solve the problem of unsatisfactory hardness, halogen-free flame retardant, salt spray resistance, flame retardancy and neutral salt spray resistance Slightly inferior, low crosslinking density of the coating film, etc., to achieve the effects of excellent flame retardancy and neutral salt spray resistance, improved water resistance and salt spray resistance, and high curing activity

Active Publication Date: 2021-02-05
黄山新佳精细材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Among the powder coating epoxy resin varieties, the most commonly used is E-12 epoxy resin, which uses bisphenol A and epichlorohydrin under the action of strong alkali It can be obtained by direct reaction, the product has low degree of molecular branching, high epoxy equivalent, and relatively low curing activity. Compared with dicyandiamide curing agents, it generally needs 180°C or even 200°C to fully cure, and the energy consumption is high.
Moreover, E-12 epoxy resin itself is generally hydrophobic, has a low degree of branching, does not contain flame-retardant elements, and the cured coating film has low cross-linking density, low hardness, and is easy to damage. It also has flame-retardant properties and neutral salt spray resistance. It is also relatively poor, and cannot meet the requirements for high hardness, halogen-free flame retardant, and salt spray resistance.

Method used

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  • Epoxy resin for high-hardness and low-temperature curing type powder coating and preparation method
  • Epoxy resin for high-hardness and low-temperature curing type powder coating and preparation method
  • Epoxy resin for high-hardness and low-temperature curing type powder coating and preparation method

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Experimental program
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preparation example Construction

[0037] The preparation method of epoxy resin comprises the following steps:

[0038] A. Add the formula amount of melamine and formaldehyde into the reaction kettle, stir, raise the temperature to 55-60°C, and add a pH regulator to adjust the pH value to 8-9, and keep it warm for 3-5h;

[0039] B, when a large amount of hexahydroxymelamine solids are separated out, and when the free melamine is lower than 2%, stop the reaction, cool to 5-10°C, carry out decompression suction filtration, and obtain hexahydroxymelamine wet material;

[0040] C. Add the hexahydroxymelamine wet material obtained in step B and the hexafluorobutanol and cyclohexane of the formula amount into the reaction kettle, stir, add a pH regulator to adjust the pH value to 3-3.5, and then heat up to 85- At 90°C, carry out the butyl etherification reaction for 2-4 hours;

[0041] D. When the mass conversion rate of hexafluorobutanol reaches more than 90%, heat up to 100-120°C to remove solvent, water and unrea...

Embodiment 1

[0046] A kind of preparation method of epoxy resin for low-temperature curing powder coating, its raw material composition comprises in mole fraction:

[0047]

[0048]

[0049] The molar dosage of the catalyst is 0.15% of the molar dosage of pentaerythritol tetraglycidyl ether.

[0050] The epoxy equivalent of the prepared epoxy resin was 492g / mol, and the softening point was 86°C.

Embodiment 2

[0052] A kind of preparation method of epoxy resin for low-temperature curing powder coating, its raw material composition comprises in mole fraction:

[0053]

[0054] The molar dosage of the catalyst is 0.08% of the molar dosage of pentaerythritol tetraglycidyl ether.

[0055] The epoxy equivalent of the prepared epoxy resin was 409g / mol, and the softening point was 80°C.

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Abstract

The invention discloses a preparation method of epoxy resin for a high-hardness and low-temperature curing type powder coating. The epoxy resin is prepared from the following raw materials in parts bymole: 3-5 parts of melamine, 30-40 parts of formaldehyde, 3-6 parts of hexafluorobutanol, 15-25 parts of cyclohexane, 2-4 parts of phosphorus pentoxide, 6-11 parts of glutaric anhydride, 2-4 parts ofpyromellitic dianhydride, 5-10 parts of pentaerythritol tetraglycidyl ether, a catalyst and a pH regulator. The obtained epoxy resin does not contain halogen elements, contains nitrogen, phosphine and other environment-friendly flame-retardant elements, has good flame retardancy, has high cross-linking density with a film obtained after low-temperature curing of a dicyandiamide curing agent, haspencil hardness of 3H or above, and has excellent water boiling resistance, neutral salt mist resistance and flame retardancy.

Description

technical field [0001] The invention belongs to the field of powder coatings, and relates to a preparation method of epoxy resin for powder coatings and an epoxy resin prepared by the method. Background technique [0002] Powder coating has the advantages of no pollution, saving energy and resources, and good comprehensive performance of the coating film. It is widely used in surface coating in daily decoration, automobile industry and other fields. [0003] Pure epoxy resin powder coating has good adhesion and good solvent resistance of the coating film, so it is widely used in indoor coating. In order to further reduce energy consumption, low-temperature curing powder coatings have always been a research hotspot. At present, the curing system is mainly dicyandiamide and 2-phenylimidazoline, although 2-phenylimidazoline can effectively reduce the curing temperature as a curing agent, but due to the low crosslinking density of the cured coating film, the coating film is eas...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G59/02C09D163/00C09D5/03C09D5/18C08G59/50
CPCC08G59/022C08G59/02C09D163/00C09D5/03C09D5/18C08G59/504
Inventor 余筱栋余金煌庄健方国平
Owner 黄山新佳精细材料有限公司
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