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CN-121975403-A - High-adhesion high-temperature-resistant powder coating and preparation method thereof

CN121975403ACN 121975403 ACN121975403 ACN 121975403ACN-121975403-A

Abstract

The application belongs to the technical field of powder coatings, and particularly provides a high-adhesion high-temperature-resistant powder coating and a preparation method thereof. The high-adhesion high-temp. resistant powder paint is made up by using epoxy resin and organosilicon resin as composite resin matrix, using pigment and zirconium phosphate to cover potassium hexatitanate whisker, calcium silicate, mica powder, talcum powder and low-melting glass powder as heat-resisting pigment filler, adding solidifying agent, levelling agent, defoaming agent and adhesion promoter, etc. and making them pass through the processes of high-speed mixing, melting extrusion and pulverizing. The powder coating still has better adhesive force and impact resistance after high temperature and cold and hot circulation.

Inventors

  • YANG QINGWEI
  • MEI BIHUA
  • LIU JUN
  • JI HUABIN

Assignees

  • 浙江超浪新材料有限公司

Dates

Publication Date
20260505
Application Date
20260407

Claims (10)

  1. 1. The high-adhesion high-temperature-resistant powder coating is characterized by comprising, by weight, 25-45 parts of epoxy resin, 15-25 parts of organic silicon resin, 1-5 parts of a curing agent, 0.3-0.8 part of a leveling agent, 0.2-0.7 part of a defoaming agent, 0.5-2.5 parts of an adhesion promoter, 2-6 parts of a pigment, 5-20 parts of zirconium phosphate coated potassium hexatitanate whisker, 2-5 parts of calcium silicate, 3-8 parts of mica powder, 5-7 parts of talcum powder and 10-30 parts of low-melting-point glass powder.
  2. 2. The high-adhesion high-temperature-resistant powder coating as claimed in claim 1, wherein the preparation method of the zirconium phosphate coated potassium hexatitanate whisker comprises the following steps: s1, pretreating potassium hexatitanate whisker with an acid solution, washing and drying to obtain an activated whisker; s2, adsorbing and reacting the activated whisker with a zirconium salt solution and a phosphate solution in sequence, washing and drying to obtain powder; S3, carrying out heat treatment on the powder at 400-500 ℃ for 1-3h under an inert atmosphere to obtain the powder.
  3. 3. The high-adhesion high-temperature-resistant powder coating according to claim 2, wherein in the step S1, the acid solution is one of a hydrochloric acid solution, a sulfuric acid solution and a nitric acid solution, the concentration is 0.5-1mol/L, and the pretreatment condition is ultrasonic at room temperature for 10-30min.
  4. 4. The high-adhesion high-temperature-resistant powder coating according to claim 2, wherein in the step S2, the concentration of the zirconium salt solution is 0.1-0.15mol/L, the pH is 2-3, and the concentration of the phosphate solution is 0.15-0.2mol/L.
  5. 5. The high-adhesion high-temperature-resistant powder coating according to claim 2, wherein in the step S2, the temperature of adsorption and reaction is 55-70 ℃, the time of adsorption is 0.5-1h, and the time of reaction is 1-3h.
  6. 6. The high-adhesion high-temperature-resistant powder coating as claimed in claim 1, wherein the epoxy resin is bisphenol A type solid epoxy resin, and the epoxy equivalent is 600-850g/eq.
  7. 7. The high-adhesion high-temperature-resistant powder coating as claimed in claim 1, wherein the curing agent is dicyandiamide.
  8. 8. The high-adhesion high-temperature-resistant powder coating according to any one of claims 1 to 7, wherein the low-melting-point glass powder is subjected to siliconizing treatment by uniformly mixing the low-melting-point glass powder with hydroxyl silicone oil, and then carrying out grinding reaction for 1 to 3 hours under the protection of inert gas at 120 to 140 ℃.
  9. 9. The method for preparing the high-adhesion high-temperature-resistant powder coating according to any one of claims 1 to 8, which is characterized by comprising the following steps: (1) Weighing epoxy resin, organic silicon resin, curing agent, leveling agent, defoamer, adhesion promoter, zirconium phosphate coated potassium hexatitanate whisker, calcium silicate, mica powder, talcum powder and low-melting-point glass powder according to a formula, and carrying out high-speed mixing to obtain premix; (2) And (3) feeding the premix into a double-screw extruder, and performing melt extrusion, tabletting, cooling, crushing and sieving.
  10. 10. The method of claim 9, wherein in the step (2), the twin-screw extruder is at a temperature of 80-90 ℃ in the first zone, 100-110 ℃ in the second zone, 120-130 ℃ in the third zone, and the screw speed is 200-300rpm.

Description

High-adhesion high-temperature-resistant powder coating and preparation method thereof Technical Field The application belongs to the technical field of powder coatings, and particularly relates to a high-adhesion high-temperature-resistant powder coating and a preparation method thereof. Background The powder coating is a solvent-free environment-friendly coating composed of solid resin, filler and auxiliary agent, and is particularly suitable for protecting the surface of a metal part working in a high-temperature environment. However, since the coating and the surface of the metal substrate are mainly bonded by covalent bonds or ionic bonds, these bonds weaken or even break at high temperatures, and in addition, the thermal expansion coefficients of the coating and the metal substrate are different, shrinkage of the two is asynchronous when subjected to thermal shock cycles, huge shear stress is generated at the interface, and when the shear stress exceeds the interface bonding strength, the coating peels off. In order to improve the performances of the coating such as adhesive force at high temperature, a high-temperature resistant auxiliary agent can be added, for example, the patent application document with publication number CN108047887A discloses a high-temperature resistant powder coating, which comprises the following raw materials of epoxy resin, polyester resin, flatting agent, antioxidant, high-temperature resistant auxiliary agent and pigment filler, wherein the high-temperature resistant auxiliary agent consists of silicon micropowder, mica powder and silane coupling agent. The silane coupling agent can improve the adhesive force at normal temperature and medium temperature to a certain extent, but under the long-term high-temperature environment, the silane coupling agent can generate thermal hydrolysis reaction, and the interfacial shear stress generated by mismatching of the thermal expansion coefficients of the coating and the metal substrate can easily generate microcracks on the coating, so that the adhesive force is reduced or the coating is peeled off in a brittle manner at high temperature. Disclosure of Invention In order to solve the problems, the application provides a high-adhesion high-temperature-resistant powder coating and a preparation method thereof. The application provides a high-adhesion high-temperature-resistant powder coating which comprises, by weight, 25-45 parts of epoxy resin, 15-25 parts of organic silicon resin, 1-5 parts of a curing agent, 0.3-0.8 part of a leveling agent, 0.2-0.7 part of a defoaming agent, 0.5-2.5 parts of an adhesion promoter, 2-6 parts of a pigment, 5-20 parts of zirconium phosphate coated potassium hexatitanate whisker, 2-5 parts of calcium silicate, 3-8 parts of mica powder, 5-7 parts of talcum powder and 10-30 parts of low-melting glass powder. Further, the preparation method of the zirconium phosphate coated potassium hexatitanate whisker comprises the following steps: s1, pretreating potassium hexatitanate whisker with an acid solution, washing and drying to obtain an activated whisker; s2, adsorbing and reacting the activated whisker with a zirconium salt solution and a phosphate solution in sequence, washing and drying to obtain powder; S3, carrying out heat treatment on the powder at 400-500 ℃ for 1-3h under an inert atmosphere to obtain the powder. In the step S1, the acid solution is one of hydrochloric acid solution, sulfuric acid solution and nitric acid solution, the concentration is 0.5-1mol/L, and the pretreatment condition is ultrasonic at room temperature for 10-30min. Further, in the step S2, the concentration of the zirconium salt solution is 0.1-0.15mol/L, the pH is 2-3, and the concentration of the phosphate solution is 0.15-0.2mol/L. Further, in the step S2, the temperature of adsorption and reaction is 55-70 ℃, the time of adsorption is 0.5-1h, and the time of reaction is 1-3h. Further, the epoxy resin is bisphenol A type solid epoxy resin, and the epoxy equivalent is 600-850g/eq. Further, the curing agent is dicyandiamide. Further, the low-melting-point glass powder is subjected to siliconizing treatment by adopting a method that the low-melting-point glass powder and hydroxyl silicone oil are uniformly mixed and then subjected to grinding reaction for 1-3 hours under the protection of inert gas at 120-140 ℃. The application also provides a preparation method of the high-adhesion high-temperature-resistant powder coating, which comprises the following steps: (1) Weighing epoxy resin, organic silicon resin, curing agent, leveling agent, defoamer, adhesion promoter, zirconium phosphate coated potassium hexatitanate whisker, calcium silicate, mica powder, talcum powder and low-melting-point glass powder according to a formula, and carrying out high-speed mixing to obtain premix; (2) And (3) feeding the premix into a double-screw extruder, and performing melt extrusion, tabletting, cooling, crushing and sieving. Further,