Glass fiber reinforced PA66 composite material with low friction coefficient and preparation method thereof

Abstract

The invention discloses a low-friction-coefficient glass fiber reinforced PA66 composite material and a preparation method thereof. The low-friction-coefficient glass fiber reinforced PA66 composite material comprises 5-15 parts of low-viscosity PA66 resin; 30 to 40 parts of medium viscosity PA66 resin; 40 to 45 parts of modified glass fiber; 8 to 12 parts of polytetrafluoroethylene; 2-5 parts of molybdenum disulfide; 0.5 to 1.5 parts of an anti-floating fiber agent; 0.2 to 0.6 part of a lubricant; 0.2 to 0.6 part of an antioxidant; 0.1 to 0.5 part of black powder; the viscosity of the low-viscosity PA66 resin is 2.2-2.4, the viscosity of the medium-viscosity PA66 resin is 2.6-2.8, and the diameter of the modified glass fiber is 10 microns. Adding other components except the modified glass fiber into a high-speed stirrer according to the proportion, and mixing for 1-2 minutes to obtain a premix; and adding the premix into a double-screw extruder through a main feeding hopper, adding modified glass fibers at a side feeding position, and carrying out melting, pelletizing and extrusion to obtain the composite material. The friction coefficient is effectively reduced, and the dispersion effect of each phase in the material is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and in particular to a low-friction-coefficient glass fiber reinforced PA66 composite material and a preparation method thereof. Background Art

[0002] With the rise of the "plastic-to-steel" trend, a large number of engineering plastics have flooded into the bearing, gear, and other fields. PA66, with its high strength and high rigidity, has captured a large market share. However, PA66's unique molecular structure results in high water absorption and poor friction and wear properties under dry friction conditions. This requires the preparation of superior PA66-based composites through blending and modification to improve these properties.

[0003] Polytetrafluoroethylene (PTFE) resin has a low friction coefficient due to the strong FC bond in its molecular structure. After PTFE is blended and modified with PA66, it is dispersed in the substrate in the form of particles. During the friction process, a transfer film will be formed to reduce friction.

[0004] Existing technology uses PTFE-modified PA66. The composite material's main components include: 60-80 parts PA66 resin; 10-20 parts polytetrafluoroethylene; 1-3 parts toughening agent; 1-3 parts compatibilizer; 0.5-1.5 parts lubricant; 0.2-0.6 parts antioxidant; and 0.1-1.5 parts black powder. This solution combines a certain amount of PA66 and PTFE to create an alloy, with additional additions of molybdenum disulfide and modified glass fiber. While a high glass fiber content enhances material performance, it can easily cause floating fibers, affecting the material's friction coefficient and appearance. The addition of polytetrafluoroethylene also affects the dispersion of the glass fiber in the material. Furthermore, this system has a low upper limit on the friction coefficient, making it unsuitable for some applications. Summary of the Invention

[0005] In order to overcome the above problems existing in the prior art, the present invention provides a low friction coefficient glass fiber reinforced PA66 composite material and a preparation method thereof.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a low friction coefficient glass fiber reinforced PA66 composite material, including 5-15 parts of low-viscosity PA66 resin; 30-40 parts of medium-viscosity PA66 resin; 40-45 parts of modified glass fiber; 8-12 parts of polytetrafluoroethylene; 2-5 parts of molybdenum disulfide; 0.5-1.5 parts of anti-floating agent; 0.2-0.6 parts of lubricant; 0.2-0.6 parts of antioxidant; 0.1-0.5 parts of black powder; The viscosity of the low-viscosity PA66 resin is 2.2-2.4, the viscosity of the medium-viscosity PA66 resin is 2.6-2.8, and the diameter of the modified glass fiber is 10 μm.

[0007] In the above-mentioned low-friction-coefficient glass fiber reinforced PA66 composite material, the polytetrafluoroethylene is a powder of 10-15 μm.

[0008] In the above-mentioned low-friction-coefficient glass fiber reinforced PA66 composite material, the molybdenum disulfide is a 10 μm powder.

[0009] In the above-mentioned low-friction-coefficient glass fiber reinforced PA66 composite material, the lubricant is one of polyethylene wax and pentaerythritol stearate.

[0010] In the above-mentioned low-friction-coefficient glass fiber reinforced PA66 composite material, the anti-floating fiber agent is a short-chain branched stearic acid amide with a polar group.

[0011] In the above-mentioned low-friction-coefficient glass fiber reinforced PA66 composite material, the antioxidant is at least one of phosphite and β-(3,5-di-tert-butyl-4-hydroxyphenyl).

[0012] A method for preparing a low-friction-coefficient glass fiber reinforced PA66 composite material, used to prepare the above-mentioned low-friction-coefficient glass fiber reinforced PA66 composite material, specifically comprising the following steps: Step 1: Add PA66 resin, polytetrafluoroethylene, molybdenum disulfide, anti-floating agent, lubricant, antioxidant, and black powder into a high-speed blender according to the proportion and mix for 1-2 minutes to obtain a premix; Step 2: Add the premix obtained in step 1 into a twin-screw extruder through a main feeding hopper, and add modified glass fiber at a side feeding point. After melting, pelletizing, and extrusion, a glass fiber-reinforced wear-resistant PA66 composite material can be obtained.

[0013] In the above-mentioned method for preparing a low-friction coefficient glass fiber reinforced PA66 composite material, in step 2, the barrel temperature of the twin-screw extruder is 260°C-280°C, the screw speed is 320r / min, and the vacuum degree is -0.04MPa.

[0014] The beneficial effect of the present invention is that low-diameter modified chopped glass fiber is used and an appropriate amount of anti-floating fiber agent is added. When the glass fiber diameter is low, its specific surface area is higher, and it can fully contact with the wetting agent to improve compatibility. Products with lower glass fiber diameter have better effects in improving floating fibers and warping. The anti-floating fiber agent further reduces the risk of floating fibers appearing on the surface of the material and is also helpful in reducing the friction coefficient.

[0015] The introduction of molybdenum disulfide, a solid lubricant, into the PTFE-modified PA66 material further enhances the dispersion of the various phases in the material and reduces the friction coefficient. The glass fiber-reinforced, wear-resistant PA66 of the present invention can be better applied in fields such as bearing sleeves. DETAILED DESCRIPTION

[0016] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below in conjunction with specific implementation methods.

[0017] This embodiment discloses a low-friction-coefficient glass fiber reinforced PA66 composite material, which specifically includes 5-15 parts of low-viscosity PA66 resin; 30-40 parts of medium-viscosity PA66 resin; 40-45 parts of modified glass fiber; 8-12 parts of polytetrafluoroethylene; 2-5 parts of molybdenum disulfide; 0.5-1.5 parts of an anti-floating agent; 0.2-0.6 parts of a lubricant; 0.2-0.6 parts of an antioxidant; and 0.1-0.5 parts of black powder.

[0018] The low-viscosity PA66 resin has a viscosity of 2.2-2.4; the medium-viscosity PA66 resin has a viscosity of 2.6-2.8; the diameter of the modified glass fiber is 10 μm; the polytetrafluoroethylene D50 is a powder of 10-15 μm; the molybdenum disulfide D50 is a powder of 10 μm; the lubricant is one of polyethylene wax and pentaerythritol stearate; the anti-floating agent is a short-chain stearic acid amide with a polar group; and the antioxidant is at least one of phosphite and β-(3,5-di-tert-butyl-4-hydroxyphenyl).

[0019] The specific preparation method is as follows: Step 1, PA66 resin, polytetrafluoroethylene, molybdenum disulfide, anti-fibering agent, lubricant, antioxidant, and black powder are added into a high-speed blender according to the proportion and mixed for 1-2 minutes to obtain a premix; Step 2: Add the premix obtained in step 1 into a twin-screw extruder through a main feeding hopper, and add modified glass fiber at a side feeding point. After melting, pelletizing, and extrusion, a glass fiber-reinforced wear-resistant PA66 composite material can be obtained.

[0020] In step 2, the barrel temperature of the twin-screw extruder is 260° C.-280° C., the screw speed is 320 r / min, and the vacuum degree is -0.04 MPa.

[0021] Based on the above preparation method, four composite materials as described in Table 1 were prepared, wherein Comparative Examples 1-3 were used for comparison. The performance of the four composite materials was tested, and the test results are shown in Table 2.

[0022] Table 1 Composite material formulation Table 2 Composite material performance test results As can be seen from Tables 1 and 2, the friction coefficient of the existing PTFE-modified PA66 materials (Comparative Examples 1 to 3) tested under the GB10006-88 standard is approximately 0.12-0.14, and the mass wear is approximately 49-72 mg. However, after the introduction of molybdenum disulfide, the friction coefficient of the composite material (Example 1) can be as low as 0.08, and the mass wear is as low as 26 mg. The composite material and preparation method disclosed in this example effectively reduce the wear and friction coefficient of the material.

[0023] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the spirit and scope of protection of the present invention, and such modifications or equivalent substitutions shall also be deemed to fall within the scope of protection of the present invention.

Claims

1. A low friction coefficient glass fiber reinforced PA66 composite material, characterized in that: It includes 5-15 parts of low-viscosity PA66 resin; 30-40 parts of medium-viscosity PA66 resin; 40-45 parts of modified glass fiber; 8-12 parts of polytetrafluoroethylene; 2-5 parts of molybdenum disulfide; 0.5-1.5 parts of anti-floating agent; 0.2-0.6 parts of lubricant; 0.2-0.6 parts of antioxidant; and 0.1-0.5 parts of black powder. The viscosity of the low-viscosity PA66 resin is 2.2-2.4, the viscosity of the medium-viscosity PA66 resin is 2.6-2.8, and the diameter of the modified glass fiber is 10 μm.

2. The low friction coefficient glass fiber reinforced PA66 composite material according to claim 1, characterized in that: The polytetrafluoroethylene is in the form of 10-15 μm powder.

3. The low friction coefficient glass fiber reinforced PA66 composite material according to claim 1, characterized in that: The molybdenum disulfide is in the form of 10 μm powder.

4. The low friction coefficient glass fiber reinforced PA66 composite material according to claim 1, characterized in that: The lubricant is one of polyethylene wax and pentaerythritol stearate.

5. The low friction coefficient glass fiber reinforced PA66 composite material according to claim 1, characterized in that: The anti-fiber floating agent is a short-chain stearic acid amide with a polar group.

6. The low friction coefficient glass fiber reinforced PA66 composite material according to claim 1, characterized in that: The antioxidant is at least one of phosphite and β-(3,5-di-tert-butyl-4-hydroxyphenyl).

7. A method for preparing a low friction coefficient glass fiber reinforced PA66 composite material, characterized in that: The method for preparing a low-friction-coefficient glass fiber reinforced PA66 composite material according to any one of claims 1 to 6 specifically comprises the following steps: Step 1: Add PA66 resin, polytetrafluoroethylene, molybdenum disulfide, anti-floating agent, lubricant, antioxidant, and black powder into a high-speed blender according to the proportion and mix for 1-2 minutes to obtain a premix; Step 2: Add the premix obtained in step 1 into a twin-screw extruder through a main feeding hopper, and add modified glass fiber at a side feeding point. After melting, pelletizing, and extrusion, a glass fiber-reinforced wear-resistant PA66 composite material can be obtained.

8. The method for preparing a low friction coefficient glass fiber reinforced PA66 composite material according to claim 7, characterized in that: In step 2, the barrel temperature of the twin-screw extruder is 260° C.-280° C., the screw speed is 320 r / min, and the vacuum degree is -0.04 MPa.

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