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CN-122011923-A - Powder coating for automobile calipers and preparation method and application thereof

CN122011923ACN 122011923 ACN122011923 ACN 122011923ACN-122011923-A

Abstract

The invention belongs to the technical field of powder coatings, and particularly relates to a powder coating for an automobile caliper, and a preparation method and application thereof. The preparation raw materials of the powder coating for the automobile calipers comprise low-hydroxyl-value hydroxyl-terminated polyester resin, medium-hydroxyl-value hydroxyl-terminated polyester resin, isocyanate curing agent, accelerator and air permeability agent, wherein the hydroxyl value of the low-hydroxyl-value hydroxyl-terminated polyester resin is 30-60mgKOH/g, the hydroxyl value of the medium-hydroxyl-value hydroxyl-terminated polyester resin is 75-190mgKOH/g, the accelerator comprises dibutyl tin laurate accelerator, and the air permeability agent comprises benzoin and air permeability wax. The invention adopts the low hydroxyl-terminated polyester resin and the medium hydroxyl-terminated polyester resin to compound, adopts benzoin and breathable wax to compound as the breathable agent, and combines with the accelerator of specific types, so that the powder coating has good water resistance, can effectively solve the problem of poor secondary adhesive force after the water resistance of the caliper coating, and remarkably improves the corrosion resistance, high temperature resistance and high humidity resistance of the base material.

Inventors

  • PENG ZHENYU
  • LI GUANG
  • GAO QINGFU
  • ZHOU LIANGYUN
  • WU PENGZHOU
  • HUANG YONGCHENG

Assignees

  • 擎天材料科技有限公司
  • 中国电器科学研究院股份有限公司

Dates

Publication Date
20260512
Application Date
20260116

Claims (10)

  1. 1. The powder coating is characterized in that the preparation raw materials of the powder coating comprise low-hydroxyl-terminated polyester resin, medium-hydroxyl-terminated polyester resin, isocyanate curing agent, accelerator and air permeability agent; the hydroxyl value of the low hydroxyl value hydroxyl-terminated polyester resin is 30-60mgKOH/g, and the hydroxyl value of the medium hydroxyl value hydroxyl-terminated polyester resin is 75-190mgKOH/g; the accelerator comprises dibutyl tin laurate accelerator; the air-permeable agent comprises benzoin and air-permeable wax.
  2. 2. The powder coating of claim 1, wherein the low hydroxyl terminated polyester resin has a viscosity of 3000 to 6000 mPa-s at 200 ℃; And/or, the glass transition temperature of the low hydroxyl-terminated polyester resin is 56-60 ℃; And/or the reactivity of the low hydroxyl-terminated polyester resin is 200 to 420s at 180 ℃.
  3. 3. The powder coating of claim 1, wherein the medium hydroxyl number hydroxyl terminated polyester resin has a viscosity of 2000 to 8000 mPa-s at 200 ℃; and/or, the glass transition temperature of the medium hydroxyl value hydroxyl terminated polyester resin is 58-60 ℃; and/or, the medium hydroxyl number hydroxyl terminated polyester resin has a reactivity of 100 to 250s at 180 ℃.
  4. 4. The powder coating according to claim 1, wherein the mass ratio of benzoin to the gas-permeable wax in the gas-permeable agent is 1 (2-5), and/or the gas-permeable wax comprises at least one of polyethylene wax, polypropylene wax, polyamide modified wax.
  5. 5. The powder coating according to claim 1, wherein the preparation raw materials of the powder coating comprise, by mass, 35-55 parts of low-hydroxyl-terminated polyester resin, 1.8-5.5 parts of medium-hydroxyl-terminated polyester resin, 18-30 parts of isocyanate curing agent, 0.9-2.2 parts of accelerator and 0.9-2.2 parts of air permeable agent.
  6. 6. The powder coating of any one of claims 1-5, wherein the powder coating is prepared from a raw material further comprising at least one of a leveling agent, a gloss enhancer, a pigment, and a filler.
  7. 7. The powder coating according to claim 6, wherein the powder coating is prepared from the following raw materials, by mass, 35-55 parts of low hydroxyl-terminated polyester resin, 1.8-5.5 parts of medium hydroxyl-terminated polyester resin, 18-30 parts of isocyanate curing agent, 0.9-2.2 parts of accelerator, 0.9-2.2 parts of air permeability agent, 0.9-2.2 parts of leveling agent, 0.5-1.1 parts of gloss enhancer, 2.7-5.5 parts of pigment and 9-25 parts of filler.
  8. 8. A method of preparing a powder coating as claimed in any one of claims 1 to 7, comprising the steps of: mixing the preparation raw materials, carrying out melt extrusion and crushing to obtain the powder coating.
  9. 9. The method according to claim 8, wherein the melt extrusion temperature is 90 to 120 ℃ and/or the particle diameter after pulverization is 28 to 35 μm.
  10. 10. An automotive caliper comprising the powder coating of any one of claims 1-7.

Description

Powder coating for automobile calipers and preparation method and application thereof Technical Field The invention belongs to the technical field of powder coatings, and particularly relates to a powder coating for an automobile caliper, and a preparation method and application thereof. Background The automobile calipers are used as an important ring of an automobile brake system, are positioned on the inner side of a hub and cling to a brake disc, can rub with the brake disc to generate high temperature in daily use, and can be influenced by temperature and humidity and ultraviolet rays when exposed in the air. Therefore, the automobile calipers are required to be high-temperature and high-humidity resistant, corrosion resistant and aging resistant, as well as have bright colors in appearance. As a powder coating applied to the surface coating of the automobile calipers, the powder coating has higher requirements on water resistance, high temperature and high humidity resistance, corrosion resistance, aging resistance and the like. The base material of traditional car calliper is cast iron, and this kind of base material surface roughness is high, the porosity is big, uses conventional primer unable completely to isolate steam and base material, and steam is easy to permeate into in the hole, makes inside metal of calliper corrode to influence the adhesive force of base material and surface coating, cause the further corruption of metal base material, reduce metal material's intensity, seriously influence calliper's life. In addition, the powder coating of calipers is single-layer powder construction spraying, the conventional base powder system such as epoxy polyester and polyester system cannot completely meet the aging requirement, the secondary adhesive force after water resistance is poor, and the corrosion resistance and the high-temperature high-humidity resistance of a base material cannot be well improved. Therefore, the powder coating which has good water resistance and can effectively solve the problem of poor secondary adhesion after water resistance of the caliper coating and remarkably improve the corrosion resistance, high temperature resistance and high humidity resistance of the base material has very important significance. Disclosure of Invention The present invention aims to solve one or more of the technical problems of the prior art described above, and at least provides an advantageous option. Specifically, the powder coating for the automobile calipers is good in water resistance, the problem of poor secondary adhesion after the calipers are coated with water resistance can be effectively solved, and the corrosion resistance and the high-temperature high-humidity resistance of a base material are remarkably improved. The invention is characterized in that the raw materials for preparing the powder coating comprise low-hydroxyl-terminated polyester resin, medium-hydroxyl-terminated polyester resin, isocyanate curing agent, accelerator and air permeability agent. The hydroxyl value of the low hydroxyl value hydroxyl-terminated polyester resin is 30-60mgKOH/g, the hydroxyl value of the medium hydroxyl value hydroxyl-terminated polyester resin is 75-190mgKOH/g, the accelerator comprises dibutyl tin laurate accelerator, and the air permeable agent comprises benzoin and air permeable wax. The invention adopts the low hydroxyl-terminated polyester resin and the medium hydroxyl-terminated polyester resin to compound, adopts benzoin and breathable wax to compound as the breathable agent, and combines with the accelerator of specific types, so that the powder coating has good water resistance, can effectively solve the problem of poor secondary adhesive force after the water resistance of the caliper coating, and remarkably improves the corrosion resistance and high-temperature and high-humidity resistance of the base material. Accordingly, in a first aspect the present invention provides a powder coating for automotive calipers. Specifically, the preparation raw materials of the powder coating for the automobile calipers comprise low-hydroxyl-terminated polyester resin, medium-hydroxyl-terminated polyester resin, isocyanate curing agent, accelerator and air permeability agent; the hydroxyl value of the low hydroxyl value hydroxyl-terminated polyester resin is 30-60mgKOH/g, and the hydroxyl value of the medium hydroxyl value hydroxyl-terminated polyester resin is 75-190mgKOH/g; the accelerator comprises dibutyl tin laurate accelerator; the air-permeable agent comprises benzoin and air-permeable wax. Preferably, the hydroxyl value of the low hydroxyl value hydroxyl terminated polyester resin is from 35 to 45mgKOH/g. Preferably, the low hydroxyl-terminated polyester resin has a viscosity of 3000 to 6000 mPas at 200 ℃, and more preferably, the low hydroxyl-terminated polyester resin has a viscosity of 3000 to 5000 mPas at 200 ℃. Preferably, the low hydroxyl number hydroxyl terminated polyester