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CN-121652673-B - Anti-collision powder coating and preparation method thereof

CN121652673BCN 121652673 BCN121652673 BCN 121652673BCN-121652673-B

Abstract

The invention discloses an anti-collision powder coating and a preparation method thereof, and relates to the field of coatings. The preparation method comprises the steps of uniformly mixing epoxy resin, phenolic epoxy curing agent, methylimidazole catalyst, partial thermal expansion material, glass fiber, leveling agent, benzoin and pure polytetrafluoroethylene wax at room temperature to obtain premix, carrying out melt blending and low-temperature extrusion on the premix to obtain sheet-shaped material, crushing the sheet-shaped material into base material powder, controlling the particle size to be 30-50 microns, and uniformly mixing the base material powder and the residual thermal expansion material at normal temperature and low speed to obtain the target powder coating. The dual buffer network constructed by the invention realizes the multistage dissipation of impact energy, and the special ultra-high epoxy equivalent resin and the special curing agent form a tough and elastic matrix network, so that the coating can bear 80 cm high strong impact and has extremely high flexibility through phi 5mm shaft bending.

Inventors

  • CHEN JUN
  • CHEN WEIYI
  • LI LUN
  • LI YU
  • SHI ZE
  • LAI LIN
  • HUANG XIAOBIN
  • WANG ZHEN

Assignees

  • 成都信达高分子材料有限公司

Dates

Publication Date
20260508
Application Date
20260209

Claims (9)

  1. 1. The preparation method of the anti-collision powder coating is characterized by comprising the following steps of: S100, uniformly mixing epoxy resin, a phenolic epoxy curing agent, a methylimidazole catalyst, a part of thermal expansion material, glass fiber, a leveling agent, benzoin and pure polytetrafluoroethylene wax at room temperature to obtain a premix; s200, carrying out melt blending on the premix, and carrying out low-temperature extrusion to obtain a sheet material; S300, crushing the sheet material into base material powder, and controlling the particle size to be 30-50 microns; S400, uniformly mixing the base material powder and the residual heat expansion material under the condition of normal temperature and low speed to obtain a target powder coating; the epoxy equivalent of the epoxy resin is 4000-6000 g/eq, and the hydroxyl equivalent of the phenolic epoxy curing agent is 180-250 g/eq; The preparation method of the epoxy resin comprises the following steps: step 1, etherifying bisphenol A, epichlorohydrin and benzyl trimethyl ammonium chloride at 63-67 ℃ for 3-5 hours, heating the system to 78-82 ℃, and distilling under reduced pressure for 1-2 hours under vacuum to obtain a prepolymer; Step 2, regulating and stabilizing the temperature of the prepolymer within a range of 68-72 ℃, and then starting to execute a cyclic reaction, wherein the total cyclic frequency is controlled to be 25-30 times, and each cycle comprises a closed-loop reaction stage and a chain extension reaction stage; And step 3, after all chain extension cycles are completed, dropwise adding an alkali solution, reacting for 100-140 minutes at 67-72 ℃, washing the obtained resin solution, dehydrating, and adding an antioxidant to obtain the target epoxy resin.
  2. 2. The preparation method of the epoxy resin composite material is characterized by comprising, by weight, 800-1000 parts of an epoxy resin, 70-85 parts of a phenolic epoxy curing agent, 5-10 parts of a methylimidazole catalyst, 15-20 parts of a thermal expansion material, 180-220 parts of glass fibers, 8-12 parts of a leveling agent, 2-4 parts of benzoin and 4-6 parts of pure polytetrafluoroethylene wax; Wherein, part of the thermal expansion material is 7-10 parts, and the rest of the thermal expansion material is 8-10 parts.
  3. 3. The preparation method of claim 1, wherein in the step 1, the molar ratio of bisphenol A to epichlorohydrin is 1:8-12, the adding amount of benzyl trimethyl ammonium chloride is 1.5-2.5% of the mass of bisphenol A, and in the step 3, the alkali liquor is an aqueous solution of NaOH, and the molar ratio of the total adding amount of the alkali liquor to bisphenol A in the step 1 is 0.5-0.7:1 based on NaOH.
  4. 4. The method according to claim 1, wherein in step 2, Dropwise adding 28-32% w/w sodium hydroxide aqueous solution into the prepolymer at a rate of 1.5-2.5 ml/min, and continuing to react for 50-70 min at 68-72 ℃ after the dropwise adding is finished; Closing loop once, wherein the molar ratio of the total alkali liquor consumption to bisphenol A in the step 1 is 0.28-0.32:1 based on NaOH; Adding bisphenol A powder and benzyl trimethyl ammonium chloride into a system with closed loop at one time, and reacting for 80-100 minutes at 68-72 ℃; The chain is extended once, the mole ratio of the added amount of bisphenol A to the bisphenol A in the step 1 is 0.14-0.16:1, and the added amount of benzyl trimethyl ammonium chloride is 1.5-2.5% of the added amount of bisphenol A.
  5. 5. The preparation method according to claim 1, wherein in the step 2, after each 3-5 cycles are completed, the inter-cycle treatment is performed, wherein the inter-cycle treatment comprises suspending the reaction, washing the reaction system with deionized water at 55-65 ℃ and removing sodium chloride generated by the reaction.
  6. 6. The method of preparing the phenolic epoxy hardener of claim 1 comprising the steps of: step 10, adding formaldehyde solution into phenol and oxalic acid at a rate of 2-6 mL/min under the protection of nitrogen, heating to 95-100 ℃ at a rate of 0.5-1.5 ℃/min, and carrying out heat preservation reaction for 2-4 hours; Step 20, after the reaction is finished, heating to 120-140 ℃, reducing the temperature to 70-80 ℃ after decompression and dehydration, and adding alkali to neutralize until the pH value is=6-7; And 30, washing with hot water with the temperature of more than 80 ℃ until the water phase is clear, and dehydrating for 1-2 hours under the high vacuum at the temperature of 120-140 ℃ to obtain the target phenolic epoxy curing agent.
  7. 7. The method according to claim 6, wherein in step 10, the molar ratio of phenol to formaldehyde is 1:0.82-0.88, and the molar ratio of oxalic acid to phenol is 0.005-0.01:1.
  8. 8. The preparation method according to claim 1, wherein the mixing is performed for 5 to 15 minutes at 15 to 28 ℃ in step S100, the extrusion temperature is 75 to 85 ℃ in step S200, and the mixing is performed for 10 to 20 minutes at 20 to 35 ℃ in step S400.
  9. 9. An impact-resistant powder coating obtained by the production method according to any one of claims 1 to 8.

Description

Anti-collision powder coating and preparation method thereof Technical Field The invention relates to the technical field of coatings, in particular to an anti-collision powder coating and a preparation method thereof. Background The automobile chassis and the lower part of the automobile body are exposed to complex road conditions for a long time, and are extremely easy to be impacted by foreign matters such as road surface broken stone at a high speed. The continuous physical impact can directly damage the protective coating on the surface of the steel plate, so that the steel plate of the matrix is exposed and corroded, and the structural safety and the service life of the vehicle are seriously threatened. To address this challenge, the industry currently uses a liquid stone-strike resistant coating based on polyvinyl chloride (PVC) and applied to the chassis area by a high pressure spray process. However, this conventional solution has a number of obvious inherent drawbacks. Firstly, during the production and construction process, the paint can release a large amount of Volatile Organic Compounds (VOCs), which forms a significant risk to the ecological environment and the health of operators, and has insufficient environmental protection. Secondly, in order to achieve the necessary protective thickness, the coating tends to be thicker, which additionally increases the weight of the vehicle body, contrary to the development trend of light weight of automobiles. In addition, the durability of the coating is limited, the coating is easy to become brittle and crack gradually and even peel off from a substrate under the actions of long-term thermal oxidation aging, salt spray corrosion and mechanical stress, the typical service life of the coating is only five years, and long-term stable protection is difficult to provide. From the construction point of view, the high-pressure spraying process is easy to generate sagging, uneven thickness and the like, the consistency of the appearance and the performance of the coating is affected, the construction efficiency is low, and the repair after the local damage is also more complicated. In summary, the existing PVC stone-strike resistant paint has bottlenecks in the aspects of environmental protection, light weight, long-acting protection and convenience in construction. At the same time, the market places higher demands on the overall properties of the coating, such as being intact under more severe impact conditions, having more excellent flexibility to resist deformation, and possessing more excellent resistance to corrosion and chemical media. Therefore, the development of a novel high-performance stone-impact-resistant coating which can comprehensively surpass the prior art and has the advantages of environmental protection, light weight, long-acting, easy construction and the like has become a subject with important industrial value and technical urgency. Disclosure of Invention The invention aims to solve the defects and provide an anti-collision powder coating and a preparation method thereof, and the novel high-performance stone-impact-resistant coating with high impact resistance, high flexibility and environmental protection is obtained. In order to solve the technical problems, the invention adopts the following technical scheme: a preparation method of an anti-collision powder coating comprises the following steps: S100, uniformly mixing epoxy resin, a phenolic epoxy curing agent, a methylimidazole catalyst, a part of thermal expansion material, glass fiber, a leveling agent, benzoin and pure polytetrafluoroethylene wax at room temperature to obtain a premix; s200, carrying out melt blending on the premix, and carrying out low-temperature extrusion to obtain a sheet material; S300, crushing the sheet material into base material powder, and controlling the particle size to be 30-50 microns; And S400, uniformly mixing the base material powder and the residual heat expansion material at normal temperature and low speed to obtain the target powder coating. Different from the conventional thinking of blending all fillers at one time, the invention introduces the thermal expansion material into the system twice, firstly embeds the thermal expansion material into the resin matrix by melt extrusion, and secondly attaches the thermal expansion material to the surface of the base material particles by physical mixing at low temperature. Finally, a double buffer network is constructed in the coating, the internal thermal expansion material is used as a uniformly dispersed stress buffer point, and the thermal expansion material on the surface becomes an independent response unit which is more sensitive to external impact. The two materials cooperate when the coating is impacted instantaneously and violently, and impact energy is efficiently dissipated through multi-stage and multi-layer expansion deformation. In order to fully exert the buffer mechanism, the meth