Bio-based TPV (thermoplastic vulcanizate) material for automobile skin and preparation method of bio-based TPV material

Abstract

The invention relates to the field of TPV materials, and particularly discloses a bio-based TPV material for automobile skin and a preparation method thereof, the bio-based TPV material for automobile skin comprises the following raw materials by weight: 30-90 parts of bio-based polypropylene, 40-80 parts of ethylene propylene diene monomer, 0.5-2 parts of a light stabilizer, 0.5-2 parts of an antioxidant, 1-40 parts of white oil, and 0.5-3 parts of a vulcanization crosslinking agent. 1-5 parts of a vulcanization crosslinking aid and 5-12 parts of a filler; the vulcanization cross-linking auxiliary agent comprises a heat-resistant auxiliary agent and a cross-linking auxiliary agent, the heat-resistant auxiliary agent is magnesium oxide and magnesium methacrylate, and the cross-linking auxiliary agent is at least one of N, N '-m-phenylene bismaleimide and triallyl isocyanurate; according to the invention, magnesium oxide and magnesium methacrylate are compounded as the heat-resistant auxiliary agent, and then the heat-resistant auxiliary agent and the cross-linking auxiliary agent are in synergistic interaction, so that the cross-linking density of the TPV material is improved, and the tear strength and peel strength of the material are further enhanced.

Description

Technical Field

[0001] The present application relates to the field of TPV materials, and in particular to a bio-based TPV material for automobile surfaces and a preparation method thereof. Background Art

[0002] The instrument panel skin material is the exposed part of the instrument panel structure. The selection of materials and processes has a crucial impact on the overall quality of the instrument panel. At present, most instrument panels are covered with slush-molded polyvinyl chloride (PVC) skin, but PVC has shortcomings in terms of odor, volatile organic compounds, and aging resistance. Thermoplastic polyolefin elastomer (TPV) is a mixture of rubber and polyolefin. It not only has excellent properties such as low density, low odor, and low VOC, but can also be recycled. It is widely used in the automotive manufacturing, wire and cable, medical and other fields.

[0003] The TPV skin is composed of a TPV layer and a base fabric layer. The ordinary TPV skin is made by directly hot pressing the TPV and the base fabric, resulting in low peel strength and tear strength, which cannot meet the production requirements of the dashboard skin. At the same time, with the continuous development and application of biotechnology, the bio-based materials industry has also developed and grown rapidly, and the requirements for the renewability of TPV materials used in automotive interior skins have gradually increased. Summary of the invention

[0004] In order to improve the mechanical properties and renewable requirements of existing TPV automobile interior skins, the present application provides a bio-based TPV material for automobile skins and a preparation method thereof.

[0005] In the first aspect, the present application provides a bio-based TPV material for automobile skin, which adopts the following technical solution: A bio-based TPV material for automobile skin comprises the following raw materials in parts by weight: 30-90 parts of bio-based polypropylene, 40-80 parts of ethylene propylene diene monomer rubber, 0.5-2 parts of light stabilizer, 0.5-2 parts of antioxidant, 1-40 parts of white oil, 0.5-3 parts of vulcanization crosslinking agent, 1-5 parts of vulcanization crosslinking aid, and 5-12 parts of filler; the vulcanization crosslinking aid comprises a heat-resistant aid and a crosslinking aid, the heat-resistant aid is magnesium oxide and magnesium methacrylate, and the crosslinking aid is at least one of N,N'-m-phenylene bismaleimide and triallyl isocyanurate.

[0006] By adopting the above technical solution, magnesium oxide and magnesium methacrylate as heat-resistant additives can improve the heat resistance of TPV materials, and enable TPV materials to still have high tear strength and elongation at break under high temperature aging. Magnesium oxide can also act as a filler and promoter, and can enhance the hardness of TPV materials. Magnesium methacrylate can play a role in cross-linking, and has good compatibility with EPDM rubber and bio-based polypropylene. It can form cross-linking bonds with free radicals generated by bio-based polypropylene and EPDM rubber, increase the cross-linking density of TPV materials, and enhance the tensile strength and tear strength of TPV materials. N, N'-m-phenylene bismaleimide and triallyl isocyanurate are used as cross-linking additives, which can react with the matrix material to form a three-dimensional cross-linked network. This cross-linked network can significantly improve the tear strength and peel strength of the material and reduce cracking and deformation on the TPV surface.

[0007] Preferably, the magnesium methacrylate is synthesized in situ from methacrylic acid and magnesium oxide.

[0008] Preferably, the method for in-situ synthesis of magnesium methacrylate comprises the following specific steps: pre-plasticizing bio-based polypropylene and EPDM rubber, then adding magnesium oxide and continuing to knead, and adding methacrylic acid dropwise and kneading to generate magnesium methacrylate by in-situ reaction.

[0009] By adopting the above technical scheme, magnesium methacrylate is synthesized in situ by methacrylic acid and magnesium oxide. The generated magnesium methacrylate acts as a cross-linking agent, chemically reacts with bio-based polypropylene and EPDM rubber molecules to form a cross-linking structure, thereby improving the peel strength and tear strength of the TPV material.

[0010] Preferably, the vulcanization crosslinking agent is a peroxide.

[0011] Preferably, the filler is at least one of diatomite, heat-resistant fiber, bamboo powder and carbon nanotubes.

[0012] By adopting the above technical scheme, diatomite, heat-resistant fiber, bamboo powder, and carbon nanotubes are used as fillers to enhance the strength and wear resistance of TPV materials. Diatomite has a nano-scale porous structure and good adsorption capacity, with more surface hydroxyl groups, and has the advantages of light texture, large specific surface area, heat resistance, and corrosion resistance. Bamboo powder is a natural filler with low density, which can make the prepared TPV material lightweight, improve biodegradability, and enhance the rigidity of TPV materials. Heat-resistant fibers and carbon nanotubes can improve the thermal stability and aging resistance of TPV materials, and can enable TPV materials to maintain good strength in high temperature environments.

[0013] Preferably, the heat-resistant fiber is a hollow polyimide fiber.

[0014] By adopting the above technical solution, the hollow polyimide fiber has low thermal conductivity and high mechanical strength, effectively insulates heat, improves the thermal insulation performance, tensile strength and impact resistance of the material, helps to reduce the temperature inside the car and improve riding comfort. The polyimide center control structure can reduce the fiber density, thereby reducing the overall density of the TPV material. At the same time, the center control structure also helps to absorb and block sound, reducing noise during the driving process of the car.

[0015] Preferably, the filler is pre-modified, and the modification method comprises the following specific steps: pre-heating the filler, washing it with water, acid washing it, drying it, and then subjecting it to high temperature treatment, then mixing the filler with a silane coupling agent, stirring it evenly at 50-60°C, and drying it to obtain a modified filler.

[0016] By adopting the above technical solution, the filler is acid-washed in advance, impurities on the filler surface can be removed, and the surface of the filler is activated, which can enhance the compatibility of the filler with bio-based polypropylene and EPDM rubber. After high-temperature treatment, the filler is mixed with a silane coupling agent, which can react with the active groups on the surface of the filler to form chemical bonds, and react with the molecular chains in the bio-based polypropylene and EPDM rubber matrix materials to form a bridging effect, thereby enhancing the interface bonding force between the filler and the matrix, thereby improving the mechanical strength and heat resistance of the composite material.

[0017] In the second aspect, the present application provides a method for preparing a bio-based TPV material for automobile skin, using the following technical solution: A method for preparing a bio-based TPV material for automobile skin comprises the following specific steps: The heat-resistant additive and the cross-linking additive are mixed in advance to form a vulcanization cross-linking agent additive, and then the bio-based polypropylene, EPDM rubber, the vulcanization cross-linking agent additive, the filler, and the vulcanization cross-linking agent are mixed, extruded and granulated to obtain a semi-finished product; the semi-finished product is then mixed with white oil, an antioxidant, and a light stabilizer, extruded and granulated to obtain a bio-based TPV material for automobile skin.

[0018] By adopting the above technical solution, the bio-based TPV material for automobile surface has good tear strength and elongation at break due to the synergistic effect of various components. At the same time, the TPV automobile surface prepared by combining bio-based polypropylene and EPDM rubber has the advantages of light weight and low odor, which enables TPV materials to be sustainable and renewable.

[0019] Preferably, the extrusion temperature of the semi-finished product is 180-220°C, and the extrusion temperature of the finished TPV material is 140-200°C.

[0020] In summary, this application has the following beneficial effects: 1. Since magnesium oxide and magnesium methacrylate in this application are used as heat-resistant additives, the heat resistance of TPV materials is improved, and the TPV materials have higher tear strength and elongation at break under high-temperature aging. Magnesium oxide can act as a filler and promoter, and magnesium methacrylate can act as a cross-linking aid. It has good compatibility with EPDM rubber and bio-based polypropylene matrix materials, and enhances the tensile strength and tear strength of TPV materials. N, N'-m-phenylene bismaleimide and triallyl isocyanurate are compounded as cross-linking aids, which can form a three-dimensional cross-linked network with EPDM rubber and bio-based polypropylene, thereby improving the tear strength and peel strength of TPV automotive skins.

[0021] 2. In this application, diatomite, heat-resistant fiber, bamboo powder, and carbon nanotubes are used as fillers to enhance the strength and wear resistance of TPV materials. Bamboo powder can reduce the density and weight of TPV materials, and heat-resistant fiber and carbon nanotubes can improve the thermal stability and aging resistance of TPV materials. At the same time, the heat-resistant fiber uses hollow polyimide fiber, and the central control structure of polyimide fiber can isolate heat and sound, thereby reducing the temperature and density around the car skin and improving the tensile strength and impact resistance of TPV materials. DETAILED DESCRIPTION

[0022] The present application is further described in detail below with reference to the embodiments.

[0023] All raw materials in the examples are commercially available. Example

[0024] Example 1 This embodiment provides a bio-based TPV material for automobile skin, including the following raw materials in parts by weight: 60kg of bio-based polypropylene, 60kg of ethylene propylene rubber, 1.2kg of light stabilizer, 1.3kg of antioxidant, 20kg of white oil, 1.2kg of vulcanization crosslinking agent, 3kg of vulcanization crosslinking aid, and 8kg of filler; wherein the bio-based polypropylene is purchased from Veolia Huafei Polymer Technology Co., Ltd. PCR-PP, the ethylene propylene rubber is purchased from China Petroleum Jilin Petrochemical Company, the vulcanization crosslinking aid includes a heat-resistant aid and a crosslinking aid, the mass ratio of the heat-resistant aid and the crosslinking aid is 1:1, the heat-resistant aid is magnesium oxide and magnesium methacrylate, and the crosslinking aid is N, N'-m-phenylene bismaleimide. The light stabilizer is light stabilizer 770, the vulcanization crosslinking agent is diisopropylbenzene peroxide, the filler is diatomite, and the antioxidant is antioxidant 1010.

[0025] The method for preparing a bio-based TPV material for automobile skin comprises the following specific steps: S1: Bio-based polypropylene and EPDM rubber are pre-mixed at 60°C for 2 minutes, magnesium oxide is divided into two equal parts, and then one of the magnesium oxide is added and mixed for 3 minutes, and then methacrylic acid is added and mixed for 15 minutes. The mass ratio of magnesium oxide to methacrylic acid is 0.75, and magnesium methacrylate is generated in situ in the bio-based polypropylene and EPDM rubber.

[0026] S2: Add the remaining portion of magnesium oxide, filler, cross-linking aid, and vulcanization cross-linking agent, mix, stir evenly, extrude and granulate at 200°C to obtain a TPV semi-finished product, and then mix the TPV semi-finished product with white oil, antioxidant, and light stabilizer, stir evenly, extrude and granulate at 170°C to obtain a bio-based TPV material for automotive surface.

[0027] Example 2 The difference between Example 2 and Example 1 is that the amount of bio-based polypropylene used in the bio-based TPV material raw material for automobile skin is 30 kg, the amount of EPDM rubber used is 80 kg, the amount of light stabilizer used is 2 kg, the amount of antioxidant used is 0.5 kg, the amount of white oil used is 1 kg, the amount of vulcanization cross-linking agent used is 0.5 kg, the amount of vulcanization cross-linking aid used is 5 kg, and the amount of filler used is 5 kg.

[0028] Example 3 The difference between Example 3 and Example 1 is that the amount of bio-based polypropylene used in the bio-based TPV material raw material for automobile skin is 90 kg, the amount of EPDM rubber used is 40 kg, the amount of light stabilizer used is 0.5 kg, the amount of antioxidant used is 2 kg, the amount of white oil used is 40 kg, the amount of vulcanization cross-linking agent used is 3 kg, the amount of vulcanization cross-linking aid used is 1 kg, and the amount of filler used is 12 kg.

[0029] Example 4 The difference between Example 4 and Example 1 is that magnesium methacrylate is directly added in the preparation method of the bio-based TPV material for automobile skin.

[0030] The present embodiment provides a method for preparing a bio-based TPV material for automobile skin, comprising the following specific steps: S1: pre-mixing magnesium oxide and magnesium methacrylate, stirring evenly to form a heat-resistant additive, wherein the mass ratio of magnesium oxide to magnesium methacrylate is 1:1, mixing the heat-resistant additive with a cross-linking additive, stirring evenly to form a vulcanization cross-linking additive.

[0031] S2: Bio-based polypropylene, EPDM rubber, vulcanization cross-linking aid, filler, and vulcanization cross-linking agent are mixed, stirred evenly, and extruded and granulated at 200°C to obtain TPV semi-finished products. The TPV semi-finished products are then mixed with white oil, antioxidant, and light stabilizer, stirred evenly, and extruded and granulated at 170°C to obtain bio-based TPV materials for automotive surfaces.

[0032] Example 5 The difference between Example 5 and Example 1 is that the crosslinking aid in the bio-based TPV material raw material used for automobile skin is a mixture of N, N'-m-phenylene bismaleimide and triallyl isocyanurate, and the mass ratio of N, N'-m-phenylene bismaleimide to triallyl isocyanurate is 1:1.

[0033] Example 6 The difference between Example 6 and Example 5 is that the filler in the raw material of the bio-based TPV material used for the automobile surface is a mixture of bamboo powder and carbon nanotubes, and the mass ratio of bamboo powder to carbon nanotubes is 1:1.

[0034] Example 7 The difference between Example 7 and Example 5 is that the filler in the raw material of the bio-based TPV material for automobile skin is a mixture of diatomite, heat-resistant fiber, bamboo powder, and carbon nanotubes, and the mass ratio of diatomite, heat-resistant fiber, bamboo powder, and carbon nanotubes is 1:1:1:1. The heat-resistant fiber is a hollow polyimide fiber.

[0035] Example 8 The difference between Example 8 and Example 7 is that an equal amount of glass fiber is used instead of hollow polyimide fiber in the raw material of the bio-based TPV material filler used for the automobile skin.

[0036] Example 9 The difference between Example 9 and Example 7 is that the filler in the raw material of the bio-based TPV material used for the automobile surface is modified.

[0037] The method for preparing a bio-based TPV material for automobile skin comprises the following specific steps: S1: Bio-based polypropylene and EPDM rubber are pre-mixed at 60°C for 2 minutes, magnesium oxide is divided into two equal parts, and then one of the magnesium oxide is added and mixed for 3 minutes, and then methacrylic acid is added and mixed for 15 minutes. The mass ratio of magnesium oxide to methacrylic acid is 0.75, and magnesium methacrylate is generated in situ in the bio-based polypropylene and EPDM rubber.

[0038] S2: diatomite, heat-resistant fiber, bamboo powder and carbon nanotubes are mixed to form a filler, which is stirred evenly, heated to 60°C and washed with water, then pickled with a 20% sulfuric acid solution, filtered and dried, and then baked at 400°C for 3 minutes. The filler is then mixed with a silane coupling agent, the mass ratio of the filler to the silane coupling agent is 1:1, wherein the silane coupling agent is KH-550, ultrasonically stirred at 60°C for 2 hours, and dried at 50°C to obtain a modified filler.

[0039] S3: Add the remaining portion of magnesium oxide, modified filler, cross-linking aid, and vulcanization cross-linking agent, mix, stir evenly, extrude and granulate at 200°C to obtain TPV semi-finished products, and then mix the TPV semi-finished products with white oil, antioxidant, and light stabilizer, stir evenly, extrude and granulate at 170°C to obtain bio-based TPV materials for automotive surfaces.

[0040] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that no heat-resistant additive is used in the raw material of the bio-based TPV material used for the automobile surface.

[0041] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that an equal amount of zinc oxide is used in the raw material of the bio-based TPV material used for the automobile surface instead of the heat-resistant additive.

[0042] The method for preparing a bio-based TPV material for automobile surface comprises the following specific steps: Bio-based polypropylene, EPDM rubber, zinc oxide, filler, cross-linking aid, and vulcanization cross-linking agent are mixed, stirred evenly, and extruded and granulated at 200°C to obtain a TPV semi-finished product. The TPV semi-finished product is then mixed with white oil, antioxidant, and light stabilizer, stirred evenly, and extruded and granulated at 170°C to obtain a bio-based TPV material for automotive surface.

[0043] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that no cross-linking aid is used in the bio-based TPV material raw material used for the automobile surface.

[0044] Performance Testing The following performance tests were performed on the bio-based TPV materials for automobile surfaces provided in Examples 1-9 and Comparative Examples 1-3 of the present application. The specific test results are shown in Table 1.

[0045] Detection Methods 1. Mechanical properties testing The tensile strength and elongation at break of the bio-based TPV material for steam skin prepared in this application were tested according to the standard of GB / T528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber". At the same time, the TPV material was heat aged at 200°C for 24 hours, and the elongation at break after heat aging was tested.

[0046] With reference to GB / T529-2008 "Determination of tear strength of vulcanized rubber or thermoplastic rubber", a rectangular specimen was used to test the tear strength of the bio-based TPV material for automotive skin prepared in this application.

[0047] Table 1: Performance test results data table From the performance test results, it can be seen that the magnesium oxide and magnesium methacrylate prepared in this application are used as heat-resistant additives to assist crosslinking, increase the crosslinking density of TPV materials, and enhance the tensile strength and tear strength of TPV materials. At the same time, N, N'-m-phenylene bismaleimide and triallyl isocyanurate are used as crosslinking additives to form a three-dimensional network in the TPV material system, thereby improving the tear strength and peel strength of the material and reducing cracking and deformation on the TPV surface.

[0048] It can be seen from the performance test results of Examples 7-9 that, compared with Example 8, the filler used in Example 7 has better comprehensive performance, and the polyimide fiber using the central control structure can isolate heat in time, reduce the temperature of the TPV material, and thus improve the thermal stability of the TPV material, so that the TPV material still has good strength at high temperatures.

[0049] By comparing Example 7 with Example 9, it can be seen that the comprehensive performance of the TPV material prepared in Example 9 is significantly improved after the filler is modified. This further illustrates that by sequentially performing acid washing activation, high temperature treatment, and coupling modification on the filler, the interfacial bonding force between the filler and the matrix can be enhanced, thereby improving the strength and thermal stability of the composite material.

[0050] By comparing Comparative Examples 1-3 with Example 1, it can be seen that Comparative Example 1 does not use a heat-resistant additive, Comparative Example 2 uses an equal amount of zinc oxide instead of a heat-resistant additive, and Comparative Example 3 does not use a crosslinking additive. From the performance test results, it can be seen that the tensile strength, elongation at break, and thermal stability of the prepared bio-based TPV material for the automotive surface are greatly reduced. Further explanation, the present application uses magnesium oxide and magnesium methacrylate as a heat-resistant additive, and then synergizes with a crosslinking additive to increase the crosslinking density of the TPV material, thereby enhancing the tear strength and peel strength of the material.

[0051] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A bio-based TPV material for automobile surface, characterized in that: The invention comprises the following raw materials in parts by weight: 30-90 parts of bio-based polypropylene, 40-80 parts of ethylene propylene diene monomer rubber, 0.5-2 parts of light stabilizer, 0.5-2 parts of antioxidant, 1-40 parts of white oil, 0.5-3 parts of vulcanization crosslinking agent, 1-5 parts of vulcanization crosslinking aid, and 5-12 parts of filler; the vulcanization crosslinking aid comprises a heat-resistant aid and a crosslinking aid, the heat-resistant aid is magnesium oxide and magnesium methacrylate, and the crosslinking aid is at least one of N,N'-m-phenylene bismaleimide and triallyl isocyanurate.

2. The bio-based TPV material for automobile surface according to claim 1, characterized in that: The magnesium methacrylate is synthesized in situ from methacrylic acid and magnesium oxide.

3. The bio-based TPV material for automobile surface according to claim 2, characterized in that: The method for in-situ synthesis of magnesium methacrylate comprises the following specific steps: pre-plasticizing bio-based polypropylene and EPDM rubber, then adding magnesium oxide and continuing to mix, and adding methacrylic acid dropwise and mixing, and reacting in-situ to generate magnesium methacrylate.

4. The bio-based TPV material for automobile surface according to claim 1, characterized in that: The vulcanization crosslinking agent is peroxide.

5. The bio-based TPV material for automobile surface according to claim 1, characterized in that: The filler is at least one of diatomite, heat-resistant fiber, bamboo powder and carbon nanotube.

6. The bio-based TPV material for automobile surface according to claim 5, characterized in that: The heat-resistant fiber is a hollow polyimide fiber.

7. The bio-based TPV material for automobile surface according to claim 5, characterized in that: The filler is pre-modified, and the modification method comprises the following specific steps: pre-heating the filler, washing it with water, acid washing it, drying it, and then subjecting it to high-temperature treatment; then mixing the filler with a silane coupling agent, stirring it evenly at 50-60° C., and drying it to obtain the modified filler.

8. A method for preparing a bio-based TPV material for automobile surface as claimed in any one of claims 1 to 7, characterized in that: The specific steps include: The heat-resistant additive and the cross-linking additive are mixed in advance to form a vulcanization cross-linking agent additive, and then the bio-based polypropylene, EPDM rubber, the vulcanization cross-linking agent additive, the filler, and the vulcanization cross-linking agent are mixed, extruded and granulated to obtain a semi-finished product; the semi-finished product is then mixed with white oil, an antioxidant, and a light stabilizer, extruded and granulated to obtain a bio-based TPV material for automobile skin.

9. The method for preparing the bio-based TPV material for automobile surface according to claim 8, characterized in that: The extrusion temperature of the semi-finished product is 180-220°C, and the extrusion temperature of the finished TPV material is 140-200°C.

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