Insulating PEEK-based composite material, its preparation method and injection molding process

Abstract

This application relates to the technical field of polymer materials, and specifically discloses an insulating PEEK-based composite material, its preparation method, and an injection molding process. An insulating PEEK-based composite material includes the following components in parts by weight: 80-90 parts of polyetheretherketone; 5-10 parts of polytetrafluoroethylene; 9-12 parts of lubricant; 5-7 parts of modified toughening agent; the modified toughening agent uses inorganic rigid particles as the core material, and is successively coated with an inner layer and an outer layer; the inner layer includes dopamine hydrochloride and 4-methyl-7-hydroxybenzopyranone; the outer layer is a coupling agent. An injection molding process includes S1. Melting and plasticizing the composite material to obtain a molten material; S2. Injecting the molten material into a mold, performing segmented pressure holding, cooling, drying, and demolding to obtain the product. An insulating PEEK-based composite material of this application has the advantages of good toughness, high impact strength, and good insulation, and can better meet products such as fan frames under the development of lightweighting.

Description

Technical Field

[0001] The present application relates to the technical field of polymer materials, and more specifically, to an insulating PEEK-based composite material, a preparation method thereof, and an injection molding process. Background Art

[0002] Polyetheretherketone (PEEK) is a high polymer composed of repeating units containing a ketone bond and two ether bonds in the main chain structure, belonging to special polymer materials. It has physical and chemical properties such as high temperature resistance and chemical resistance to drugs, and can be used as a high temperature resistant structural material and an electrical insulating material.

[0003] Power devices are provided on live equipment, such as power modules for providing different voltages. A large amount of heat will be dissipated during their operation. In order to maintain the stability of the equipment, a small cooling fan is generally built in. The raw material of the fan housing is generally PEEK material.

[0004] Although PEEK composite materials have high mechanical properties, good wear resistance and heat resistance, they have a large stiffness. Some manufacturers will mix a certain amount of PTFE to improve the flexibility of the products. However, with the development of product lightweight, the demand for the impact resistance of the fan housing has also increased. Summary of the Invention

[0005] In order to improve the flexibility of the PEEK-based composite material and increase the impact strength, the present application provides an insulating PEEK-based composite material, a preparation method thereof, and an injection molding process.

[0006] In a first aspect, the present application provides an insulating PEEK-based composite material, adopting the following technical solution:

[0007] An insulating PEEK-based composite material comprises the following components in parts by weight:

[0008] 80 - 90 parts of polyetheretherketone; 5 - 10 parts of polytetrafluoroethylene; 9 - 12 parts of lubricant; 5 - 7 parts of modified toughening agent;

[0009] The modified toughening agent has an inorganic rigid particle as the core material, and is sequentially coated with an inner layer and an outer layer; for the inner layer, the preparation raw materials include dopamine hydrochloride and 4-methyl-7-hydroxybenzopyranone; the outer layer is a coupling agent.

[0010] By adopting the above technical solution: there is an elastic interface phase between the inorganic rigid particles and the matrix resin. The existence of this elastic interface phase provides a good interface combination between the rigid particles with a certain deformation ability and the matrix. This structure can make the rigid particles toughen the matrix.

[0011] Coupling agents improve the compatibility and interfacial adhesion between rigid particles and the matrix, better absorb and disperse external impact energy, improve the toughness of the composite material, and enhance the impact strength. However, the coating effect of the coupling agent depends on the hydroxyl sites on the surface of the rigid particles. Therefore, a polyhydroxy coating layer is formed on the surface of the rigid particles with dopamine hydrochloride, and 4-methyl-7-hydroxycoumarin is added to further introduce a hydroxyl structure, so that the presence of the inner layer provides more reaction sites for the coating of the coupling agent, improving the coating effect, thereby significantly enhancing the toughness of the matrix and increasing the impact strength with the modified toughening agent.

[0012] After testing, after adding the modified toughening agent, the impact strength of the prepared product can reach 111 - 120 MPa, and the resistivity is as high as 8×10^11; when using equal amounts of silane-modified calcium carbonate (i.e., without using the intermediate layer coating) to replace the modified toughening agent, the impact strength of the prepared product significantly drops to 84 MPa, and when 4-methyl-7-hydroxycoumarin is not added during the preparation of the modified lubricant, the impact strength of the prepared product drops to 96 MPa, indicating that calcium carbonate with an intermediate layer coating containing 4-methyl-7-hydroxycoumarin can significantly improve the impact strength of the product, has good insulation performance, and is more suitable for the fan housing under lightweight development.

[0013] Optionally, the weight ratio of the polyetheretherketone to the polytetrafluoroethylene is 10:1.

[0014] By adopting the above technical solution: after further preparing a product from the composite material obtained when the weight ratio of polyetheretherketone to polytetrafluoroethylene is 10:1, the properties of the prepared product are all better.

[0015] Optionally, the preparation method of the modified toughening agent is: adding inorganic rigid particles to water, dispersing to obtain a dispersion; adding tris(hydroxymethyl)aminomethane hydrochloride, dopamine hydrochloride, and 4-methyl-7-hydroxycoumarin to the dispersion, stirring and mixing, filtering to remove the filtrate, and drying to obtain inner layer-coated particles;

[0016] Adding the inner layer-coated particles to the coupling agent solution, stirring and mixing, washing, centrifuging, and drying to obtain the product.

[0017] By adopting the above technical solution: tris(hydroxymethyl)aminomethane hydrochloride forms an alkaline environment, enabling dopamine hydrochloride to polymerize and achieve the coating of inorganic rigid particles.

[0018] Optionally, the volume-to-weight ratio of the water, inorganic rigid particles, and dopamine hydrochloride is 200 mL: 8 - 12 g: 0.8 - 1.2 g.

[0019] Optionally, the inorganic rigid particle is one of calcium carbonate, talc powder, wollastonite, montmorillonite, and coal ash.

[0020] By adopting the above technical solutions: The requirements for inorganic rigid particles in this application are relatively low, and the above substances can all be used to prepare the modified toughening agent.

[0021] Optionally, the volume-to-weight ratio of the water, tris(hydroxymethyl)aminomethane hydrochloride, and 4-methyl-7-hydroxycoumarin is 200 mL: 0.35 - 0.40 g: 0.12 - 0.17 g.

[0022] By adopting the above technical solutions: When the dosages of tris(hydroxymethyl)aminomethane hydrochloride and 4-methyl-7-hydroxycoumarin are within the above ranges, it is more effective to increase the hydroxyl sites on the surface of the inorganic rigid particles, improve the coating effect of the coupling agent, and thus improve the toughness of the product.

[0023] Optionally, the volume-to-weight ratio of the coupling agent solution to the inner layer coated particles is 100 mL: 15 - 25 g.

[0024] Optionally, the concentration of the coupling agent solution is 0.8 - 1.2%.

[0025] By adopting the above technical solutions: When the coupling agent concentration is within the above range, the coating effect is improved by effectively avoiding the formation of multi-layer coatings and ensuring a better coating layer.

[0026] In the second aspect, this application provides a preparation method for an insulating PEEK-based composite material, adopting the following technical solutions:

[0027] A preparation method for an insulating PEEK-based composite material includes the following steps:

[0028] Dry the polyetheretherketone, polytetrafluoroethylene, lubricant, and modified toughening agent, and then add them to an extruder for melt co-extrusion and granulation to obtain the product.

[0029] By adopting the above technical solutions: The steps are simple, and the PEEK masterbatch can be obtained by co-mixing and then extrusion.

[0030] In the third aspect, this application provides an injection molding process for an insulating PEEK-based composite material, adopting the following technical solutions:

[0031] An injection molding process for an insulating PEEK-based composite material includes the following steps:

[0032] S1. Melt and plasticize the composite material to obtain a molten material;

[0033] S2. Inject the molten material into a mold, perform segmented pressure holding and cooling to obtain a product;

[0034] S3. Dry and demold the product to obtain the finished product.

[0035] By adopting the above technical solution: the steps are simple, and PEEK products such as fan frames are obtained by injection molding.

[0036] In summary, the present application has the following beneficial effects:

[0037] 1. A modified toughening agent is added to the composite material of the present application. By virtue of the toughening function of inorganic rigid particles, the coating of the intermediate layer increases the hydroxyl sites on the surface of the inorganic rigid particles, enhances the coating effect of the coupling agent on the inorganic rigid particles, and further improves the compatibility and interfacial adhesion performance between the inorganic rigid particles and the resin matrix, so as to better absorb and disperse the external impact energy, improve the toughness of the composite material, and enhance the impact strength;

[0038] 2. The intermediate layer of the modified toughening agent of the present application uses dopamine hydrochloride as the coating raw material, and 4-methyl-7-hydroxybenzopyranone is further added to make the formed intermediate layer have more hydroxyl sites, so that the modified toughening agent effectively improves the impact strength of the composite material. Specific Embodiments

[0039] The present application will be further described in detail below with reference to the embodiments. The sources of each component are as follows. Except for the following special instructions, the components are from commercial sources.

[0040] Calcium carbonate, purchased from Hebei Qingjiang New Material Technology Co., Ltd., with a particle size of 2500 mesh;

[0041] Talc powder, purchased from Penglai Yongfengda Superfine Talc Powder Factory, with a particle size of 2500 mesh;

[0042] Wollastonite, purchased from Dachun (Hebei) Building Materials Technology Co., Ltd., with a particle size of 1250 mesh;

[0043] Dopamine hydrochloride, purchased from Chengdu Chaojiuba Biotechnology Co., Ltd., product number WKQ-0019657;

[0044] 4-Methyl-7-hydroxybenzopyranone, CAS 90-33-5, purchased from Qianyan Chemical Technology (Wuhan) Co., Ltd.;

[0045] Polyetheretherketone, purchased from Guangzhou Xichuan Plastic Raw Materials Co., Ltd., product number PEEK 2000UFP10;

[0046] Polytetrafluoroethylene, purchased from Dongguan Zhengtao Plastic Co., Ltd., product number F-201;

[0047] Molybdenum disulfide, with a particle size of 3000 mesh.

[0048] Preparation Example 1

[0049] A modified toughening agent uses inorganic rigid particles as the core material, and is successively coated with an inner layer and an outer layer on the surface, and is obtained by the following steps:

[0050] Add 10 g of inorganic rigid particles (calcium carbonate) to 200 mL of water, disperse at a speed of 4000 rpm for 3 min, then add 0.3 g of tris(hydroxymethyl)aminomethane hydrochloride, 0.1 g of dopamine hydrochloride, and 0.1 g of 4-methyl-7-hydroxycoumarin, and stir at 25 °C and 8000 rpm for 4 h. Filter to remove the filtrate, dry at 120 °C for 5 h, and grind for standby to obtain the inner layer coated particles;

[0051] Take 1 mL of coupling agent KH550 and 99 mL of ethanol-aqueous solution with a volume concentration of 90%, stir at 60 °C and 800 rpm for 10 min to obtain a coupling agent solution; then add 20 g of inner layer coated particles, stir at 80 °C and 600 rpm for 3 h, add 200 mL of water for washing, centrifuge to remove the supernatant, and dry at 50 °C for 20 min to obtain.

[0052] Preparation Example 2

[0053] A modified toughening agent uses inorganic rigid particles as the core material, and the surface is sequentially coated with an inner layer and an outer layer, and is obtained through the following steps:

[0054] Add 8 g of inorganic rigid particles (talc powder) to 200 mL of water, disperse at a speed of 4000 rpm for 3 min, then add 0.3 g of tris(hydroxymethyl)aminomethane hydrochloride, 0.8 g of dopamine hydrochloride, and 0.1 g of 4-methyl-7-hydroxycoumarin, and stir at 25 °C and 8000 rpm for 4 h. Filter to remove the filtrate, dry at 120 °C for 5 h, and grind for standby to obtain the inner layer coated particles;

[0055] Take 0.8 mL of coupling agent KH550 and 99.2 mL of ethanol-aqueous solution with a volume concentration of 90%, stir at 60 °C and 800 rpm for 10 min to obtain a coupling agent solution; then add 15 g of inner layer coated particles, stir at 80 °C and 600 rpm for 3 h, add 200 mL of water for washing, centrifuge to remove the supernatant, and dry at 50 °C for 20 min to obtain.

[0056] Preparation Example 3

[0057] A modified toughening agent uses inorganic rigid particles as the core material, and the surface is sequentially coated with an inner layer and an outer layer, and is obtained through the following steps:

[0058] Add 12 g of inorganic rigid particles (wollastonite) to 200 mL of water, disperse at a speed of 4000 rpm for 3 min, then add 0.3 g of tris(hydroxymethyl)aminomethane hydrochloride, 1.2 g of dopamine hydrochloride, and 0.1 g of 4-methyl-7-hydroxycoumarin. Stir at 25 °C and 8000 rpm for 4 h, filter to remove the filtrate, dry at 120 °C for 5 h and grind for standby, then the inner layer coated particles are obtained;

[0059] Take 1.2 mL of coupling agent KH550 and 98.8 mL of ethanol-aqueous solution with a volume concentration of 90%, stir at 60 °C and 800 rpm for 10 min to obtain a coupling agent solution; then add 25 g of inner layer coated particles, stir at 80 °C and 600 rpm for 3 h, add 200 mL of water for washing, centrifuge to remove the supernatant, and dry at 50 °C for 20 min to obtain.

[0060] Preparation Examples 4-6

[0061] A modified toughening agent, different from Preparation Example 1 in that the dosages of tris(hydroxymethyl)aminomethane hydrochloride and 4-methyl-7-hydroxycoumarin are different, specifically as follows:

[0062] In Preparation Example 4, the addition amounts of tris(hydroxymethyl)aminomethane hydrochloride and 4-methyl-7-hydroxycoumarin and the weight-to-volume ratio of water are 0.38 g:0.15 g:200 mL.

[0063] In Preparation Example 5, the addition amounts of tris(hydroxymethyl)aminomethane hydrochloride and 4-methyl-7-hydroxycoumarin and the weight-to-volume ratio of water are 0.35 g:0.12 g:200 mL.

[0064] In Preparation Example 6, the addition amounts of tris(hydroxymethyl)aminomethane hydrochloride and 4-methyl-7-hydroxycoumarin and the weight-to-volume ratio of water are 0.34 g:0.17 g:200 mL.

[0065] Example 1

[0066] An insulating PEEK-based composite material, its components and weights are shown in Table 1, and it is obtained through the following steps:

[0067] Dry polyetheretherketone, polytetrafluoroethylene, lubricant (silane-modified molybdenum disulfide), and modified toughening agent (prepared from Preparation Example 1) at 120 °C for 30 min and then mix, and then add them to an extruder, and carry out melt co-extrusion and granulation under the conditions of a blending temperature of 350 °C and a screw speed of 350 rpm to obtain.

[0068] Table 1 Components and weights (kg) in Examples 1-3 and Comparative Examples 1-2

[0069] Component Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Polyetheretherketone 85 80 90 85 85 Polytetrafluoroethylene 8.5 5 10 8.5 8.5 Silane-modified molybdenum disulfide 10.5 9 12 10.5 10.5 Modified toughening agent 6 5 7 3 10

[0070] Preparation method of silane-modified molybdenum disulfide: Take 1.2 mL of coupling agent KH550 and 98.8 mL of ethanol-aqueous solution with a volume concentration of 90%, stir at 60 °C and 800 rpm for 10 min to obtain a coupling agent solution; then add 25 g of molybdenum disulfide, stir at 80 °C and 600 rpm for 3 h, add 200 mL of water for washing, centrifuge to remove the supernatant, and dry at 50 °C for 20 min to obtain.

[0071] This embodiment also provides an injection molding process, including the following steps:

[0072] S1. Add the composite material into an injection molding machine for melting and plasticizing, set the screw speed at 60 rpm, the nozzle temperature at 390 °C, the front section temperature of the barrel at 380 °C, the middle section temperature of the barrel at 375 °C, and the rear section temperature of the barrel at 370 °C to obtain a molten material;

[0073] S2. Inject the molten material into the mold under a pressure of 5 MPa, set the mold temperature at 185 °C and the injection time at 2 s, then perform segmented pressure holding (the first stage holds the pressure at 40 MPa for 0.5 s, the second stage holds the pressure at 120 MPa for 5 s, and the third stage holds the pressure at 90 MPa for 1 s), cool, and the cooling time is 15 s to obtain a product;

[0074] S3. Dry the product at 90 °C for 13 h, open the mold, and obtain a specimen.

[0075] Comparative Example 3

[0076] An insulating PEEK-based composite material, the difference from Example 1 is that silane-modified calcium carbonate is used instead of the modified toughening agent; the preparation method of the silane-modified calcium carbonate is as follows:

[0077] Take 1.2 mL of coupling agent KH550 and 98.8 mL of ethanol-aqueous solution with a volume concentration of 90%, stir at 60 °C and 800 rpm for 10 min to obtain a coupling agent solution; then add 25 g of calcium carbonate, stir at 80 °C and 600 rpm for 3 h, add 200 mL of water for washing, centrifuge to remove the supernatant, and dry at 50 °C for 20 min to obtain.

[0078] Comparative Example 4

[0079] An insulating PEEK-based composite material, the difference from Example 1 is that 4-methyl-7-hydroxybenzopyranone is not added during the preparation of the modified toughening agent.

[0080] Examples 4 - 8

[0081] An insulating PEEK-based composite material, which is different from that in Example 1 in that the usage of the modified toughening agent refers to Table 2, but the dosage of the modified toughening agent remains unchanged.

[0082] Table 2 Usage of the modified toughening agent in Examples 4-8

[0083] Example 4 5 6 7 8 Preparation example of modified toughening agent 2 3 4 5 6

[0084] Performance testing

[0085] The composite materials prepared in the examples and comparative examples were injection molded into specimens according to the injection molding process in Example 1, and the following performance tests were carried out on the specimens.

[0086] Specimen size parameters: Specimen 1A according to the provisions in DIN EN ISO 527-2.

[0087] Testing methods

[0088] 1. For the specimens prepared from the composite material of Example 1, the tensile strength, elastic modulus, and elongation at break were measured according to DIN EN ISO 527-2; the compressive strength (1%, 2%, 5%) was measured according to EN ISO 604; the ball indentation hardness was measured according to IS0 2039-1; the glass transition temperature and melting temperature were measured according to DIN EN ISO 11357; the thermal expansion was measured according to DIN EN ISO 11359-1;2 (test conditions: 23-60 °C, 23-100 °C, 100-150 °C); the specific heat and thermal conductivity were measured according to IS0 22007-4:2008.

[0089] The test results were: tensile strength 108 MPa, elastic modulus 6000 MPa, elongation at break 13%, compressive strength (1%) 26 MPa, compressive strength (2%) 49 MPa, compressive strength (5%) 117 MPa, ball indentation hardness 296 MPa, glass transition temperature 149 °C, melting temperature 345 °C, thermal expansion (23-60 °C) 4×10 -5 / k, thermal expansion (23-100 °C) 4×10 -5 / k, thermal expansion (100-150 °C) 6×10 -5 / k, specific heat 1.2 J / (g(k), thermal conductivity 0.65, surface resistivity 10 3 -10 12 Ω.

[0090] 2. For the specimens prepared from the composite materials of Examples 2-8 and Comparative Examples 1-4, the impact strength (Charpy) was measured according to DIN EN ISO 179-1eU, and the surface resistivity was measured according to DIN EN 61340-2-3. The test results are shown in Table 3.

[0091] Table 3 Performance Test Results

[0092] Item Impact strength (MPa) Surface resistivity (Ω) Example 1 120 <![CDATA[8×10 11 > Example 2 111 <![CDATA[6.6×10 11 > Example 3 117 <![CDATA[4.8×10 11 > Example 4 113 <![CDATA[2.4×10 11 > Example 5 116 <![CDATA[5.5×10 11 <!-- 5 -->]]> Example 6 129 <![CDATA[5.8×10 12 > Example 7 124 <![CDATA[2.3×10 12 > Example 8 128 <![CDATA[3.1×10 12 > Comparative Example 1 101 <![CDATA[4.7×10 11 > Comparative Example 2 105 <![CDATA[7.3×10 11 > Comparative Example 3 84 <![CDATA[0.6×10 11 > Comparative Example 4 96 <![CDATA[3.1×10 11 >

[0093] As can be seen from Table 3, in Examples 1-3, the modified toughening agent prepared in Preparation Example 1 was used, and the impact strength of the specimens prepared could reach 111-120 MPa. The difference between Comparative Example 3 and Example 1 was that an equal amount of silane-modified calcium carbonate was used (i.e., the intermediate layer coating was not used), and the impact strength of the specimens prepared decreased significantly to 84 MPa. In the preparation process of the modified lubricant in Comparative Example 4, 4-methyl-7-hydroxybenzopyranone was not added, and the impact strength of the specimens prepared decreased to 96 MPa, indicating that the calcium carbonate coated with an intermediate layer containing 4-methyl-7-hydroxybenzopyranone could significantly improve the impact strength of the product and was more suitable for the fan housing under the development of lightweight.

[0094] The difference between Examples 6-8 and Example 1 was that the dosages of tris(hydroxymethyl)aminomethane hydrochloride and 4-methyl-7-hydroxybenzopyranone were different in the preparation process of the modified toughening agent. When the dosages of the two were within the ranges of Examples 6-8, the performance of the specimens prepared was better.

[0095] This specific embodiment is only an interpretation of the present application and does not limit the present application. Those skilled in the art can make modifications to this embodiment without creative contributions according to needs after reading this specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. An insulating PEEK-based composite material, characterized in that: The composition comprises the following components in parts by weight: 80-90 parts of polyetheretherketone; 5-10 parts of polytetrafluoroethylene; 9-12 parts of lubricant; 5-7 parts of modified toughening agent; The modified toughening agent is an inorganic rigid particle as a core material, which is coated with an inner layer and an outer layer in sequence; the inner layer is prepared from raw materials including dopamine hydrochloride and 4-methyl-7-hydroxybenzopyrone; the outer layer is a coupling agent; The preparation method of the modified toughening agent is as follows: adding inorganic rigid particles to water, dispersing to obtain a dispersion; adding tris(hydroxymethyl)aminomethane hydrochloride, dopamine hydrochloride, and 4-methyl-7-hydroxybenzopyrone to the dispersion, stirring and mixing, removing the filtrate by suction filtration, and drying to obtain inner layer coated particles; The inner layer coated particles are added to the coupling agent solution, stirred and mixed, washed, centrifuged and dried to obtain the product.

2. The insulating PEEK-based composite material according to claim 1, characterized in that: The weight ratio of the polyetheretherketone to polytetrafluoroethylene is 10:

1.

3. The insulating PEEK-based composite material according to claim 1, characterized in that: The volume-to-weight ratio of the water, the inorganic rigid particles, and dopamine hydrochloride is 200 mL: 8-12 g: 0.8-1.2 g.

4. The insulating PEEK-based composite material according to claim 1, characterized in that: The inorganic rigid particles are one of calcium carbonate, talc, wollastonite, montmorillonite and fly ash.

5. The insulating PEEK-based composite material according to claim 1, characterized in that: The volume-to-weight ratio of the water, tris(hydroxymethyl)aminomethane hydrochloride, and 4-methyl-7-hydroxybenzopyrone is 200 mL: 0.35-0.40 g: 0.12-0.17 g.

6. The insulating PEEK-based composite material according to claim 1, characterized in that: The volume-to-weight ratio of the coupling agent solution and the inner-layer coated particles is 100 mL: 15-25 g.

7. The insulating PEEK-based composite material according to claim 1, characterized in that: The concentration of the coupling agent solution is 0.8-1.2%.

8. A method for preparing the insulating PEEK-based composite material according to any one of claims 1 to 7, characterized in that: The following steps are involved: The polyetheretherketone, polytetrafluoroethylene, lubricant and modified toughening agent are dried and added into an extruder for melt co-extrusion and granulation to obtain the product.

9. An injection molding process for an insulating PEEK-based composite material, characterized in that: The composite material is prepared by the preparation method according to claim 8, and the injection molding process comprises the following steps: S1, melting and plasticizing the composite material to obtain a molten material; S2, injecting the molten material into the mold, maintaining pressure in sections, and cooling to obtain a product; S3, drying the product and demoulding.