Search

CN-122011754-A - Nylon bushing and preparation method thereof

CN122011754ACN 122011754 ACN122011754 ACN 122011754ACN-122011754-A

Abstract

The invention provides a preparation method of a nylon bushing and the nylon bushing prepared by the preparation method, which comprises the steps of, by weight, dehydrating 90-95 parts of caprolactam, heating and melting in a vacuum state, dehydrating, then adding inert gas, adding 0.25-1.2 parts of catalyst and 4-8 parts of No. 58 wax, stirring and mixing, adding 1-3 parts of hydrophobing agent and 0.3-1.2 parts of hexamethylene diisocyanate, stirring, injecting into a sealed bushing mold, and solidifying and forming. The nylon bushing prepared by the invention has good wear resistance and water absorbability.

Inventors

  • ZHANG WEI
  • LIU AIXUE
  • GONG JIANBIN
  • Yin Zongkang

Assignees

  • 宁海宏德新材料科技有限公司
  • 浙江宏德新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260316

Claims (10)

  1. 1. The preparation method of the nylon bushing is characterized by comprising the following steps of: according to parts by weight, 90-95 parts by weight of caprolactam is dehydrated, heated, melted and dehydrated in a vacuum state, and then inert gas is added; adding 0.25-1.2 parts by weight of catalyst and 4-8 parts by weight of No. 58 wax, stirring and mixing; Adding 1-3 parts by weight of a hydrophobizing agent and 0.3-1.2 parts by weight of hexamethylene diisocyanate, stirring, injecting into a sealed bushing mold, and curing and forming.
  2. 2. The method according to claim 1, wherein the dehydrating 90 to 95 parts by weight of caprolactam comprises drying caprolactam in a vacuum oven at 80 to 100 ℃ for 4 to 6 hours.
  3. 3. The preparation method according to claim 1, wherein the catalyst is NaOH, and the mass of NaOH is 0.25% -1.2% of the caprolactam.
  4. 4. The method according to claim 1, wherein the step of adding 0.25 to 1.2 parts by weight of the catalyst and 4 to 8 parts by weight of the No. 58 wax and stirring and mixing is preceded by the step of: The No. 58 wax was crushed or cut into small particles.
  5. 5. The method according to claim 1, wherein the temperature of the heating and melting is 125 ℃ to 135 ℃ and the duration is 20 to 30 minutes.
  6. 6. The method according to claim 1, wherein the step of adding 0.25 to 1.2 parts by weight of the catalyst and 4 to 8 parts by weight of the No. 58 wax, stirring and mixing comprises the steps of: Adding the catalyst, and stirring for 5-10 minutes; The No. 58 wax was added and stirred.
  7. 7. The method according to claim 1, wherein the step of adding the hydrophobizing agent and hexamethylene diisocyanate and stirring, injecting into a sealed bushing mold, and solidifying and molding comprises: Preheating the bushing mold to 160-180 ℃; adding a hydrophobing agent and hexamethylene diisocyanate, stirring, injecting into a preheated sealing bush mould, preserving the heat of the bush mould for 15-30 minutes, and solidifying and forming.
  8. 8. The method of manufacturing according to claim 1, wherein the method further comprises: and cooling the lining mould, and taking out the nylon lining in the lining mould.
  9. 9. The method of preparing according to claim 8, further comprising: The nylon liner is heat treated in an oil bath or oven at 100-120 ℃ for 1-2 hours and then cooled.
  10. 10. A nylon bushing, characterized in that the nylon bushing is manufactured by the manufacturing method according to any one of claims 1 to 9.

Description

Nylon bushing and preparation method thereof Technical Field The invention belongs to the technical field of nylon materials, and particularly relates to a nylon bushing and a preparation method thereof. Background Nylon bushings are cylindrical mechanical parts made of nylon (polyamide, PA) as a main material. The core functions of the bearing are as a supporting piece and a wear-resistant piece, and the bearing is assembled in a mechanical hole shaft to play roles in reducing friction, reducing abrasion, isolating vibration and noise. Thanks to the self-lubricity of nylon materials, it can work under oil-free or low-oil conditions, with high wear resistance and light weight. Meanwhile, the alloy has good corrosion resistance and electrical insulation, and can protect a metal matrix, prolong the service life of equipment and reduce the maintenance cost. The plastic is widely applied to automobile hinges, mechanical connecting rods, furniture hardware and various transmission mechanisms, and is an engineering plastic component with excellent performance, economy and practicability. The nylon bushing commonly used in the market at present adopts a simplified process for compression cost, so that the wear resistance and the water absorption are lower. Disclosure of Invention In order to solve the technical problems, the invention aims to provide a nylon bushing and a preparation method thereof, so as to improve the wear resistance and water absorption of the nylon bushing. The invention provides a preparation method of a nylon bushing, which comprises the following steps: according to parts by weight, 90-95 parts by weight of caprolactam is dehydrated, heated, melted and dehydrated in a vacuum state, and then inert gas is added; adding 0.25-1.2 parts by weight of catalyst and 4-8 parts by weight of No. 58 wax, stirring and mixing; Adding 1-3 parts by weight of a hydrophobizing agent and 0.3-1.2 parts by weight of hexamethylene diisocyanate, stirring, injecting into a sealed bushing mold, and curing and forming. In the production process of nylon, macromolecular chains of nylon can be broken due to degradation reactions such as high temperature, hydrolysis and the like, so that the molecular weight and viscosity are reduced. According to the invention, through adding the modification auxiliary agent HDI, namely hexamethylene diisocyanate, the modification auxiliary agent HDI can react with amino groups or carboxyl groups at the tail ends of two broken nylon chains at the same time to reconnect the two broken nylon chains, so that the average molecular weight of nylon is increased, and the chain extension or crosslinking effect of the HDI enables the material to have higher wear resistance and mechanical property, and meanwhile, the water absorption is reduced. Preferably, the dehydration of 90-95 parts by weight of caprolactam comprises drying caprolactam in a vacuum oven at 80-100 ℃ for 4-6 hours. In the scheme, the main raw materials are dried first, so that the adverse effect of residual moisture on subsequent anionic polymerization is avoided. Preferably, the catalyst is NaOH, and the mass of the NaOH is 0.25% -1.2% of that of the caprolactam. Preferably, before the step of adding 0.25-1.2 parts by weight of catalyst and 4-8 parts by weight of No. 58 wax and stirring and mixing, the preparation method further comprises: The No. 58 wax was crushed or cut into small particles. In the scheme, the No. 58 wax is crushed or cut into small particles so as to be convenient for subsequent rapid melting and dispersing. Preferably, the temperature of the heating and melting is 125-135 ℃ and the duration is 20-30 minutes. In this embodiment, caprolactam is heated and melted in a vacuum for 20-30 minutes, so that caprolactam is continuously freed of trace amounts of water and bubbles in the molten state, at which time the liquid is observed to become clear and transparent. Preferably, the step of adding 0.25-1.2 parts by weight of catalyst and 4-8 parts by weight of No. 58 wax, stirring and mixing comprises the following steps: adding the catalyst into the component A, and stirring for 5-10 minutes; The No. 58 wax was added and stirred. Preferably, the steps of adding the hydrophobing agent and the hexamethylene diisocyanate, stirring, injecting into a sealed bushing mold, and curing and forming include: Preheating the bushing mold to 160-180 ℃; adding a hydrophobing agent and hexamethylene diisocyanate, stirring, injecting into a preheated sealing bush mould, preserving the heat of the bush mould for 15-30 minutes, and solidifying and forming. The scheme firstly preheats the mould, avoids the solidification of the mould which is contacted with low temperature when the injected mixed material is not subjected to anion polymerization. Meanwhile, the mold is a sealing mold, so that material oxidation caused by air entering is avoided. Preferably, the method further comprises: and cooling the lining mould, and taking out