TPV (thermoplastic vulcanizate) sealing material, preparation method and application of TPV sealing material in automobile engine

Abstract

The invention relates to the technical field of TPV (thermoplastic vulcanizates), and discloses a TPV sealing material, a preparation method and application of the TPV sealing material in automobile engines, the TPV sealing material comprises 45-60 parts by weight of silicone rubber masterbatch, 40-55 parts by weight of polyurethane elastomer, 4-10 parts by weight of polystyrene cardanol, 0.18-0.3 part by weight of platinum catalyst and the like; a fat carbon chain of polystyrene-based cardanol contains alkenyl, hydrogen-containing silicone oil and methyl vinyl silicone rubber are subjected to a cross-linking reaction, meanwhile, polystyrene-based cardanol contains a carbamic acid ester group, the compatibility with a polyurethane elastomer is also good, the compatibility between silicone rubber and the polyurethane elastomer is improved, and the compatibility between the silicone rubber and the polyurethane elastomer is improved. The polystyrene-based cardanol contains a polystyrene molecular chain with high strength, and meanwhile, a fat carbon chain can play a role in toughening polyurethane, so that the tensile strength, the elongation at break and the tearing strength of the TPV sealing material are improved.

Description

Technical Field

[0001] This invention relates to the field of TPV thermoplastic vulcanizate technology, specifically to a TPV sealing material and its preparation method, as well as its application in automobile engines. Background Technology

[0002] TPV is a thermoplastic vulcanized rubber material, usually made of rubber, plastics, etc. through vulcanization. The main types are EPDM / polypropylene, silicone rubber / polyurethane, silicone rubber / ethylene-octene copolymer, etc. Among them, silicone rubber / polyurethane TPV has strong high temperature resistance, good aging resistance and excellent flame retardancy, and is widely used in the automotive industry, electronics and electrical appliances, sealing materials and other fields.

[0003] Due to the poor compatibility between silicone rubber and polyurethane elastomers, achieving good mixing is difficult and affects the mechanical properties of TPV materials. Therefore, compatibilization treatment of the rubber and plastic phases is necessary. Patent CN112143231B discloses a silicone rubber / polyurethane thermoplastic vulcanizate, its preparation method, and its applications. It uses a block copolymer of organosiloxanes as a compatibilizer, improving the compatibility between silicone rubber and polyurethane, resulting in excellent mechanical properties for the thermoplastic vulcanizate. However, this thermoplastic vulcanizate has low tensile strength and lacks good tear strength. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a TPV sealing material and its preparation method, as well as its application in automotive engines. This solves the problem of poor compatibility between silicone rubber and polyurethane, and improves the mechanical properties of silicone rubber-polyurethane TPV materials.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a TPV sealing material and a preparation method, comprising 45-60 parts by weight of silicone rubber masterbatch, 40-55 parts by weight of polyurethane elastomer, 4-10 parts by weight of polystyrene-based cashew nut shell extract, 0.6-1.3 parts by weight of vulcanizing agent, 0.18-0.3 parts by weight of platinum catalyst, and 0.8-1.3 parts by weight of antioxidant.

[0006] The preparation method of TPV sealing material is as follows: (1) Add solvent, 3-isopropyl-dimethylbenzyl isocyanate, cashew nut shell powder, and dibutyltin dilaurate to the reaction vessel, stir the reaction, and distill under reduced pressure. The crude product is purified by column chromatography to obtain styrene-based cashew nut shell powder monomer. The reaction formula is: In the reaction formula, n is 0-3.

[0007] (2) Add N,N-dimethylformamide and styrene cashew nut phenol monomer to the reaction vessel, stir and then introduce nitrogen gas, add azobisisobutyronitrile dropwise, stir the reaction, distill under reduced pressure, wash the product with dichloromethane, dry, and obtain polystyrene cashew nut phenol.

[0008] (3) Add silicone rubber masterbatch, polyurethane elastomer, polystyrene cashew phenol and antioxidant to torque rheometer, mix at 180-195℃ for 20-30 min at a speed of 70-100 r / min, then add vulcanizing agent and vulcanize for 5-10 min, and finally add platinum catalyst and crosslink reaction for 8-12 min to obtain TPV sealing material.

[0009] Preferably, the solvent in (1) is toluene, dichloromethane or trichloromethane.

[0010] Preferably, in (1), the amount of 3-isopropyl-dimethylbenzyl isocyanate is 100 parts by weight, cashew phenol is 150-182 parts by weight, and dibutyltin dilaurate is 0.6-0.9 parts by weight.

[0011] Preferably, (1) the reaction temperature is 20-35℃ and the reaction time is 2-4h.

[0012] Preferably, in (2), the amount of styrene cashew phenol monomer is 100 parts by weight and the amount of azobisisobutyronitrile is 1.1-1.4 parts by weight.

[0013] Preferably, the reaction temperature in (2) is 70-80℃ and the reaction time is 7-10h.

[0014] Preferably, the vulcanizing agent in (3) includes bis(2,5)-pentasulfide and bis(tert-butylperoxyisopropylbenzene).

[0015] Preferably, the antioxidant in (3) includes antioxidant 1010.

[0016] Preferably, the preparation method of silicone rubber masterbatch is as follows: 100 parts by weight of methyl vinyl silicone rubber, 30-40 parts by weight of silica, 3.4-5 parts by weight of hydroxyl silicone oil and 2.2-3.7 parts by weight of hydrogen-containing silicone oil are added to a torque rheometer and mixed at 180-195°C for 20-30 minutes to obtain silicone rubber masterbatch.

[0017] Preferably, TPV sealing materials are used in automotive engines.

[0018] The beneficial technical effects of this invention are as follows: This invention polymerizes styrene-based cashew nut shells to obtain polystyrene-based cashew nut shells, which are then blended, vulcanized, and crosslinked with silicone rubber masterbatch, polyurethane elastomer, vulcanizing agent, platinum catalyst, etc., to obtain TPV sealing material. The aliphatic carbon chain of this polystyrene-based cashew nut shells contains alkenyl groups. Under the action of a platinum catalyst, the alkenyl groups undergo a crosslinking reaction with methyl vinyl silicone rubber through hydrogen-containing silicone oil, enhancing the bonding strength between the polystyrene-based cashew nut shells and silicone rubber. Simultaneously, the polystyrene-based cashew nut shells contain urethane groups, which also have good compatibility with polyurethane elastomers. This allows the polystyrene-based cashew nut shells to act as a compatibilizer, improving the compatibility between silicone rubber and polyurethane elastomers, and thus contributing to improved mechanical properties of the TPV sealing material.

[0019] The polystyrene-based cashew phenol of this invention contains a high-strength polystyrene molecular chain, while the aliphatic carbon chain can toughen the polyurethane, further improving the tensile strength, elongation at break and tear strength of TPV material, and has good practical application in automotive engine sealing materials. Attached Figure Description

[0020] Figure 1 It is the infrared spectrum of polystyrene-based cashew phenol. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below.

[0022] Methyl vinyl silicone rubber, model 110-1, is sourced from Dongguan Shuang'ao Plastics Co., Ltd. Polyurethane elastomer, model L194A, is sourced from Dongguan Xinshengli Plastic New Material Technology Co., Ltd. Hydroxysilicone oil, model PMX-0930, and hydrogen-containing silicone oil, model Dow 1107, are both sourced from Shenzhen Chonghuaxin Technology Co., Ltd. Platinum catalyst, model XM-3051-1, is sourced from Xiemei Chemical (Guangzhou) Co., Ltd.

[0023] Example 1 (1) Add 700 mL of dichloromethane, 50 g (248.8 mmol) of 3-isopropyl-dimethylbenzyl isocyanate, 75 g (246.3 mmol) of cashew nut shell powder and 0.42 g of dibutyltin dilaurate to the reaction vessel. Stir the reaction at 25 °C for 4 h. Distill under reduced pressure. The crude product is purified by column chromatography and eluted with a mixture of petroleum ether and ethyl acetate to obtain styryl cashew nut shell powder monomer.

[0024] (2) Add 1.5 L N,N-dimethylformamide and 300 g (594.1 mmol) styrene cashew nut monomer to the reaction vessel, stir and then introduce nitrogen gas, add 3.6 g azobisisobutyronitrile dropwise, heat to 70 °C, stir and react for 10 h, distill under reduced pressure, wash the product with dichloromethane, dry, and obtain polystyrene cashew nut. Figure 1 In the infrared spectrum, 2849 cm⁻¹ -1 2912cm -1 The absorption peaks are the methyl-CH3 and methylene-CH2- groups of the cashew phenol fatty acid carbon chain, at 1721 cm⁻¹. -1 1507cm -1 These are the absorption peaks of the ester carbonyl groups -C=O- and -NH- in the carbamate group, 1443-1580 cm⁻¹. -1 These are characteristic peaks of the benzene ring.

[0025] (3) Add 5 kg of methyl vinyl silicone rubber, 150 g of silica, 23 g of hydroxyl silicone oil and 11 g of hydrogen-containing silicone oil to a torque rheometer and mix at 190 °C for 20 min to obtain silicone rubber masterbatch.

[0026] (4) Add 6 kg of silicone rubber masterbatch, 4 kg of polyurethane elastomer, 0.4 kg of polystyrene cashew phenol and 130 g of antioxidant 1010 to a torque rheometer, mix at 190 °C for 30 min at a speed of 100 r / min, then add 9 g of vulcanizing agent bis(2,5) vulcanizing agent, vulcanize for 5 min, and finally add 1.8 g of platinum catalyst, crosslink reaction for 8 min to obtain TPV sealing material.

[0027] Example 2 (1) Add 800 mL of toluene, 50 g of 3-isopropyl-dimethylbenzyl isocyanate, 91 g of cashew nut phenol and 0.3 g of dibutyltin dilaurate to the reaction vessel, stir and react at 20 °C for 4 h, distill under reduced pressure, separate and purify the crude product by column chromatography, and elute with a mixture of petroleum ether and ethyl acetate to obtain styryl cashew nut phenol monomer.

[0028] (2) Add 2L of N,N-dimethylformamide and 300g of styrene-based cashew nut phenol monomer to the reaction vessel, stir and then introduce nitrogen gas, add 4.2g of azobisisobutyronitrile dropwise, heat to 70℃, stir and react for 8h, distill under reduced pressure, wash the product with dichloromethane, dry, and obtain polystyrene-based cashew nut phenol.

[0029] (3) Add 5 kg of methyl vinyl silicone rubber, 200 g of silica, 25 g of hydroxyl silicone oil and 13.8 g of hydrogen-containing silicone oil to a torque rheometer and mix at 180 °C for 30 min to obtain silicone rubber masterbatch.

[0030] (4) Add 5 kg of silicone rubber masterbatch, 5 kg of polyurethane elastomer, 0.7 kg of polystyrene cashew phenol and 110 g of antioxidant 1010 to a torque rheometer, mix at 180 °C for 30 min at a speed of 70 r / min, then add 6 g of vulcanizing agent bis(2,5) vulcanizing agent, vulcanize for 10 min, and finally add 2.3 g of platinum catalyst, crosslink reaction for 12 min to obtain TPV sealing material.

[0031] Example 3 (1) Add 800 mL of chloroform, 50 g of 3-isopropyl-dimethylbenzyl isocyanate, 75 g of cashew nut shell powder, and 0.38 g of dibutyltin dilaurate to the reaction vessel. Stir the reaction at 35 °C for 2 h. Distill under reduced pressure. The crude product is purified by column chromatography and eluted with a mixture of petroleum ether and ethyl acetate to obtain styryl cashew nut shell powder monomer.

[0032] (2) Add 1.5L N,N-dimethylformamide and 300g styrene cashew nut phenol monomer to the reaction vessel, stir and then introduce nitrogen gas, add 3.3g azobisisobutyronitrile dropwise, heat to 80℃, stir and react for 7h, distill under reduced pressure, wash the product with dichloromethane, dry, and obtain polystyrene cashew nut phenol.

[0033] (3) Add 5 kg of methyl vinyl silicone rubber, 200 g of silica, 17 g of hydroxyl silicone oil and 18.5 g of hydrogen-containing silicone oil to a torque rheometer and mix at 195 °C for 20 min to obtain silicone rubber masterbatch.

[0034] (4) Add 4.5 kg of silicone rubber masterbatch, 5.5 kg of polyurethane elastomer, 1 kg of polystyrene cashew phenol and 80 g of antioxidant 1010 to a torque rheometer, mix at 195 °C for 20 min at a speed of 100 r / min, then add 13 g of bis-tert-butylperoxyisopropylbenzene, vulcanize for 8 min, and finally add 3 g of platinum catalyst and crosslink for 12 min to obtain TPV sealing material.

[0035] Comparative Example 1 (1) 6 kg of silicone rubber masterbatch (prepared in the same way as in Example 1), 4 kg of polyurethane elastomer, and 130 g of antioxidant 1010 were added to a torque rheometer and mixed at 190 °C for 30 min at a speed of 100 r / min. Then, 9 g of vulcanizing agent bis(2,5) vulcanizing agent was added and vulcanized for 5 min. Finally, 1.8 g of platinum catalyst was added and the crosslinking reaction was carried out for 8 min to obtain TPV sealing material.

[0036] Comparative Example 2 (1) Add 1.5 L N,N-dimethylformamide and 61.7 g (594.1 mmol) styrene to the reaction vessel, stir and then introduce nitrogen gas, add 3.6 g azobisisobutyronitrile dropwise, heat to 70 °C, stir and react for 10 h, distill under reduced pressure, wash the product with ethanol, dry and obtain polystyrene.

[0037] (2) 6 kg of silicone rubber masterbatch (prepared in the same way as in Example 1), 4 kg of polyurethane elastomer, 0.4 kg of polystyrene, and 130 g of antioxidant 1010 were added to a torque rheometer and mixed at 190 °C for 30 min at a speed of 100 r / min. Then, 9 g of vulcanizing agent bis(2,5) vulcanizing agent was added and vulcanized for 5 min. Finally, 1.8 g of platinum catalyst was added and the crosslinking reaction was carried out for 8 min to obtain TPV sealing material.

[0038] Comparative Example 3 (1) Add 700 mL of dichloromethane, 50 g of 3-isopropyl-dimethylbenzyl isocyanate, 64.6 g (246.3 mmol) of dodecylphenol (CAS No. 27193-86-8), and 0.42 g of dibutyltin dilaurate to the reaction vessel. Stir the mixture at 25 °C for 4 h. Distill under reduced pressure. The crude product is purified by column chromatography and eluted with a mixture of petroleum ether and ethyl acetate to obtain styryldodecane monomer with the following structural formula: .

[0039] (2) Add 1.5 L N,N-dimethylformamide and 275.6 g (594.1 mmol) styrene dodecane monomer to the reaction vessel, stir and then introduce nitrogen gas, add 3.6 g azobisisobutyronitrile dropwise, heat to 70 °C, stir and react for 10 h, distill under reduced pressure, wash the product with dichloromethane, dry, and obtain polystyrene dodecane.

[0040] (3) 6 kg of silicone rubber masterbatch (prepared in the same way as in Example 1), 4 kg of polyurethane elastomer, 0.4 kg of polystyrene dodecane, and 130 g of antioxidant 1010 were added to a torque rheometer and mixed at 190 °C for 30 min at a speed of 100 r / min. Then, 9 g of vulcanizing agent bis(2,5) vulcanizing agent was added and vulcanized for 5 min. Finally, 1.8 g of platinum catalyst was added and the crosslinking reaction was carried out for 8 min to obtain TPV sealing material.

[0041] Comparative Example 4 (1) At 0℃, 700 mL of dichloromethane, 22.3 g of acryloyl chloride, 75 g of cashew nut shell powder, and 24.9 g of triethylamine were added to a reaction vessel. The mixture was stirred at 25℃ for 10 h. The crude product was then purified by column chromatography and eluted with a mixture of petroleum ether and ethyl acetate to obtain acrylate-based cashew nut shell powder monomer; the structural formula is as follows: n is 0-3.

[0042] (2) Add 1.5 L N,N-dimethylformamide and 213.0 g (594.1 mmol) acrylate-based cashew phenol monomer to the reaction vessel, stir and then introduce nitrogen gas, add 3.6 g azobisisobutyronitrile dropwise, heat to 70 °C, stir and react for 10 h, distill under reduced pressure, wash the product with dichloromethane, dry, and obtain polyacrylate cashew phenol.

[0043] (3) 6 kg of silicone rubber masterbatch (prepared in the same way as in Example 1), 4 kg of polyurethane elastomer, 0.4 kg of polyacrylate cashew phenol, and 130 g of antioxidant 1010 were added to a torque rheometer and mixed at 190 °C for 30 min at a speed of 100 r / min. Then, 9 g of vulcanizing agent bis(2,5) vulcanizing agent was added and vulcanized for 5 min. Finally, 1.8 g of platinum catalyst was added and the crosslinking reaction was carried out for 8 min to obtain TPV sealing material.

[0044] The tensile properties of TPV sealing materials were tested according to GB / T 528-2009 standard. The tear strength was tested according to GB / T 529-2008 standard.

[0045] Table 1 Performance of TPV Sealing Materials

[0046] After testing, it was found that the TPV sealing material obtained by blending silicone rubber masterbatch and polyurethane elastomer in Comparative Example 1 had low tensile strength, elongation at break and tear strength. This was mainly due to the poor compatibility between silicone rubber and polyurethane elastomer, which resulted in low mechanical properties of the material.

[0047] Examples 1-3 incorporated polystyrene-based cashew nut shell extract. The aliphatic carbon chain of cashew nut shell extract contains alkenyl groups. Under the action of a platinum catalyst, the alkenyl groups undergo a crosslinking reaction with methyl vinyl silicone rubber via hydrogen-containing silicone oil, enhancing the bonding strength between polystyrene-based cashew nut shell extract and silicone rubber. Simultaneously, polystyrene-based cashew nut shell extract contains urethane groups, exhibiting excellent compatibility with polyurethane elastomers. This allows polystyrene-based cashew nut shell extract to act as a compatibilizer, improving the compatibility between silicone rubber and polyurethane elastomers, which is beneficial for improving the mechanical properties of TPV sealing materials. Furthermore, polystyrene-based cashew nut shell extract contains polystyrene molecular chains, resulting in high strength, while the aliphatic carbon chains can toughen the polyurethane, significantly improving the tensile strength, elongation at break, and tear strength of the TPV sealing material.

[0048] Compared to Example 1, Comparative Example 2 added polystyrene, which cannot act as a compatibilizer and cannot improve the compatibility between polyurethane elastomer and silicone rubber. At the same time, polystyrene does not contain aliphatic carbon chains and cannot toughen polyurethane, resulting in lower tensile strength, elongation at break and tear strength of the TPV sealing material than in Example 1.

[0049] The aliphatic carbon chain of polystyrene dodecane in Comparative Example 3 does not contain alkenyl groups, and it cannot undergo crosslinking reaction with methyl vinyl silicone rubber through hydrogen-containing silicone oil. The bonding strength and interfacial properties of the two are low, so it cannot improve the compatibility between polyurethane elastomer and silicone rubber, resulting in the tensile strength, elongation at break and tear strength of TPV sealing material being lower than those in Example 1.

[0050] The acrylate-based cashew phenol monomer in Comparative Example 4 does not contain urethane groups, resulting in low compatibility with polyurethane elastomers. This does not significantly improve the compatibility between the rubber and the polyurethane elastomer, leading to lower tensile strength, elongation at break, and tear strength of the TPV sealing material compared to Example 1.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A TPV sealing material, characterized in that, The TPV sealing material comprises 45-60 parts by weight of silicone rubber masterbatch, 40-55 parts by weight of polyurethane elastomer, 4-10 parts by weight of polystyrene-based cashew nut shell extract, 0.6-1.3 parts by weight of vulcanizing agent, 0.18-0.3 parts by weight of platinum catalyst, and 0.8-1.3 parts by weight of antioxidant. The preparation method of the polystyrene-based cashew phenol includes the following steps: (1) Add solvent, 3-isopropyl-dimethylbenzyl isocyanate, cashew nut phenol and dibutyltin dilaurate to the reaction vessel, stir the reaction, distill under reduced pressure, and purify the crude product by column chromatography to obtain styrene-based cashew nut phenol monomer. (2) Add N,N-dimethylformamide and styrene cashew nut phenol monomer to the reaction vessel, stir and then introduce nitrogen gas, add azobisisobutyronitrile dropwise, stir the reaction, distill under reduced pressure, wash the product, dry, and obtain polystyrene cashew nut phenol.

2. The TPV sealing material according to claim 1, characterized in that, The solvent in (1) is toluene, dichloromethane or trichloromethane.

3. The TPV sealing material according to claim 1, characterized in that, In (1), the amount of 3-isopropyl-dimethylbenzyl isocyanate is 100 parts by weight, cashew phenol is 150-182 parts by weight, and dibutyltin dilaurate is 0.6-0.9 parts by weight.

4. The TPV sealing material according to claim 1, characterized in that, The reaction temperature of (1) is 20-35℃ and the reaction time is 2-4h.

5. The TPV sealing material according to claim 1, characterized in that, In (2), the amount of styrene cashew phenol monomer used is 100 parts by weight, and the amount of azobisisobutyronitrile is 1.1-1.4 parts by weight.

6. The TPV sealing material according to claim 1, characterized in that, The reaction temperature in (2) is 70-80℃ and the reaction time is 7-10h.

7. The TPV sealing material according to claim 1, characterized in that, The vulcanizing agent is bis(2,5)-disulfide or bis(tert-butylperoxyisopropylbenzene); the antioxidant is antioxidant 1010.

8. The TPV sealing material according to claim 1, characterized in that, The preparation method of the silicone rubber masterbatch includes the following steps: 100 parts by weight of methyl vinyl silicone rubber, 30-40 parts by weight of silica, 3.4-5 parts by weight of hydroxyl silicone oil, and 2.2-3.7 parts by weight of hydrogen-containing silicone oil are added to a torque rheometer and mixed at 180-195℃ for 20-30 minutes to obtain silicone rubber masterbatch.

9. A method for preparing the TPV sealing material as described in any one of claims 1-8, characterized in that, The preparation method of the TPV sealing material includes the following steps: adding silicone rubber masterbatch, polyurethane elastomer, polystyrene cashew nut shell powder, and antioxidant into a torque rheometer, mixing at 180-195℃ for 20-30 min at a rotation speed of 70-100 r / min, then adding a vulcanizing agent and vulcanizing for 5-10 min, and finally adding a platinum catalyst and crosslinking for 8-12 min to obtain the TPV sealing material.

10. The application of a TPV sealing material obtained by the preparation method as described in claim 9 in an automobile engine.

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