CN112831179B - Low-water-absorption wear-resistant nylon bushing and preparation method thereof - Google Patents

Abstract

The invention provides the preparation method of the low-water-absorption wear-resistant nylon bushing, which has the advantages of few used components, easily obtained components, low cost and simple preparation process. The preparation method comprises the following steps: putting nylon 6, PTFE and nano inorganic matters into a mixer to mix for 1-2h to obtain a mixture; the weight percentages of the raw materials are as follows: 10-20% of PTFE (polytetrafluoroethylene) by weight of nylon 6, and 3-11% of nano inorganic matters by weight of nylon 6; drying the mixture at 80-90 ℃ to ensure that the water content of the mixture is not more than 0.1%; adding the mixture into an injection molding machine, heating the mixture to 220-250 ℃ by the injection molding machine to be in a molten state, and then injecting the mixture into a mold preheated to 60-80 ℃; and (5) demoulding after cooling the mould, taking out the injection molding part, and machining to obtain the nylon bushing.

Description

Low-water-absorption wear-resistant nylon bushing and preparation method thereof

Technical Field

The patent relates to a nylon lining, in particular to a low-water-absorption wear-resistant nylon lining and a preparation method thereof.

Background

CN201410298809.7 provides a composition of nylon 6 and polytetrafluoroethylene with low friction coefficient, which is prepared by adding pure water and polymerization inhibitor into a high-pressure reaction kettle, adding a certain amount of dispersant, initiator, nylon 6 powder, vinylidene fluoride, perfluoromethyl vinyl ether, maleic anhydride, heating to reaction temperature, obtaining nylon 6 with polymerized surface after reaction is finished, filtering and drying the product, mixing with polytetrafluoroethylene in a high-speed mixer, and grinding and crushing in a pulverizer to obtain the composition. The method is to surface modify nylon 6 by maleic anhydride and vinylidene fluoride monomer, and perfluoro methyl vinyl ether monomer, so as to improve compatibility with polytetrafluoroethylene, and can fully contact in the pulverizing and mixing process, and disperse more uniformly. Because the fluorine-containing polymer is coated on the surfaces of the nylon 6 particles, the surface energy of the nylon 6 particles is reduced, the scratch resistance of the surfaces of the particles is improved, and the friction coefficient of the composition is reduced. However, the method needs a plurality of auxiliary agents for polymerization reaction, the reaction process is difficult to control, and the popularization and the application are difficult.

CN200910051033.8 discloses a highly wear-resistant PA6 composite material and a preparation method thereof, the composite material comprises the following components in percentage by weight: 56-82% of nylon, 1#2-5% of wear-resistant agent, 2-5% of wear-resistant agent, 5-15% of glass fiber powder, 5-15% of glass microsphere, 2-8% of grafted toughening modifier, 0.1-0.5% of nucleating agent, 0.1-1% of antioxidant and 0.1-0.5% of lubricating dispersant. Although the PA6 composite material prepared by the method has good wear resistance, the PA6 composite material is easy to absorb water, so that the size flat wire of the PA6 composite material is large, and the PA6 composite material is not suitable for preparing precision parts. In addition, the method needs a plurality of auxiliary agents, and the product cost is high.

Disclosure of Invention

The invention aims to provide the preparation method of the low-water-absorption wear-resistant nylon lining, which has the advantages of few used components, easily obtained components, low cost and simple preparation process.

In order to achieve the purpose, the preparation method of the low-water-absorption wear-resistant nylon lining comprises the following steps:

step S1, placing nylon 6, PTFE and nano inorganic matters into a mixer to mix for 1-2 hours to obtain a mixture; the weight percentages of the raw materials are as follows: 10-20% of PTFE (polytetrafluoroethylene) by weight of nylon 6, and 3-11% of nano inorganic matters by weight of nylon 6;

step S2, drying the mixture at 80-90 ℃ to ensure that the water content of the mixture is not more than 0.1%;

s3, adding the mixture into an injection molding machine, heating the mixture to 220-250 ℃ by the injection molding machine to be in a molten state, and then injecting the mixture into a mold preheated to 60-80 ℃;

step S4: and (5) demoulding after cooling the mould, taking out the injection molding part, and machining to obtain the nylon bushing.

According to the preparation method of the low-water-absorption wear-resistant nylon lining, the nano inorganic matters comprise nano calcium carbonate and one of nano silicon dioxide or nano ceramic micro powder.

According to the preparation method of the low-water-absorption wear-resistant nylon lining, the weight of the nano silicon dioxide or the nano ceramic micro powder is 2-4% of that of nylon 6, and the weight of the nano calcium carbonate is 1-7% of that of nylon 6.

According to the preparation method of the low-water-absorption wear-resistant nylon bushing, the weight of the nano silicon dioxide or the nano ceramic micro powder is 2% of that of nylon 6, and the weight of the nano calcium carbonate is 6% of that of nylon 6.

In the preparation method of the low-water-absorption wear-resistant nylon lining, the PTFE accounts for 15-16% of the weight of the nylon 6.

The invention also provides a low-water-absorption wear-resistant nylon bushing which has low friction coefficient, small water absorption and small dimensional deformation, and is particularly suitable for being used in a high-humidity environment.

The low-water-absorption wear-resistant nylon lining is prepared according to the preparation method of the low-water-absorption wear-resistant nylon lining.

The beneficial effect of this patent: the method uses specific components to prepare the low-water-absorption wear-resistant nylon bushing which has small water absorption, small size deformation, higher tensile strength, bending strength and shock resistance, and can not generate locking phenomenon when used as the bushing.

Detailed Description

The invention is further illustrated below with reference to examples.

The preparation method of the low-water-absorption wear-resistant nylon lining comprises the following steps:

step S1, nylon 6, PTFE, nano silicon dioxide or nano ceramic micro powder and nano calcium carbonate are put into a mixer according to different weight ratios relative to the nylon 6 in the table 1 to be mixed for 1.5 hours, so as to obtain a mixture;

s2, drying the mixture at 85-87 ℃ for about 5 hours, so that the water content of the mixture is not more than 0.1%;

s3, adding the mixture into an injection molding machine, heating the mixture to 220-250 ℃ by the injection molding machine to be in a molten state, and then injecting the mixture into a mold preheated to 65-70 ℃;

step S4: and (5) demoulding after the mould is cooled, taking out the injection molding part, and machining to obtain the nylon bushings of different embodiments.

The injection molded parts or nylon bushings were tested according to the following criteria and the results are shown in table 1.

Tensile strength: ASTM D638-2003 plastic tensile property standard test method

Impact strength at room temperature: standard test method for determining impact resistance of plastic to cantilever Liang Baichui by ASTM D256-2006

Coefficient of friction: GB/T3960-2016

Water absorption rate: reference GB/T1034-2008

Flexural strength: referring to GB/T9341-2008 room temperature flexural strength, sample specification: (80X 10X 4) mm, test speed: 2mm/min

From table 1, when 10-20% by weight of the nylon 6 is PTFE, 2-4% by weight of the nylon 6 is nano silicon dioxide or nano ceramic micro powder, and 1-7% by weight of the nylon 6 is nano calcium carbonate, especially when 15% by weight of the nylon 6 is PTFE, 3% by weight of the nylon 6 is nano silicon dioxide or nano ceramic micro powder, and 5-6% by weight of the nylon 6 is nano calcium carbonate, an injection molding piece or nylon bushing prepared by the method has low friction coefficient, small water absorption and small dimensional change, and can not generate a locking phenomenon (the bushing inner hole is reduced to be fixed with a shaft penetrating through the bushing inner hole, or the bushing outer diameter is enlarged to be fixed with a hole matched with the bushing outer diameter), and has good tensile strength, bending strength and impact resistance.

In the patent, the nano ceramic micro powder is a product disclosed and sold by Nanjing Tianxing new material Co.

Table 1:

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Claims (2)

1. the preparation method of the low-water-absorption wear-resistant nylon lining is characterized by comprising the following steps of: the method comprises the following steps:

step S1, placing nylon 6, PTFE and nano inorganic matters into a mixer to mix for 1-2 hours to obtain a mixture; the nanometer inorganic matter is one of nanometer silicon dioxide or nanometer ceramic micropowder and nanometer calcium carbonate; the weight percentages of the raw materials are as follows: 15-16% of PTFE (polytetrafluoroethylene) by weight of nylon 6, 3% of nano silicon dioxide or nano ceramic micro powder by weight of nylon 6, and 5% of nano calcium carbonate by weight of nylon 6;

step S2, drying the mixture at 80-90 ℃ to ensure that the water content of the mixture is not more than 0.1%;

s3, adding the mixture into an injection molding machine, heating the mixture to 220-250 ℃ by the injection molding machine to be in a molten state, and then injecting the mixture into a mold preheated to 60-80 ℃;

step S4: and (5) demoulding after cooling the mould, taking out the injection molding part, and machining to obtain the nylon bushing.

2. The low-water-absorption wear-resistant nylon bushing is prepared by the preparation method of the low-water-absorption wear-resistant nylon bushing in claim 1.