A wear-resistant and crack-resistant polypropylene material and preparation method

Abstract

This invention relates to the field of polypropylene materials technology, and discloses a wear-resistant and crack-resistant polypropylene material and its preparation method. The wear-resistant and crack-resistant polypropylene material of this invention comprises 100 parts by weight of polypropylene resin, 2-12 parts by weight of phenylsiloxane-modified polypropylene compatibilizer, and 10-50 parts by weight of methyl vinyl silicone rubber. The main chain of the phenylsiloxane-modified polypropylene of this invention contains a polypropylene molecular chain, and the side chain contains the same siloxane group as that of methyl vinyl silicone rubber, which can act as a compatibilizer, improve the compatibility between polypropylene and methyl vinyl silicone rubber, and make the material exhibit higher mechanical properties such as tear strength. At the same time, the introduction of a siloxane structure containing a rigid benzene ring into the side chain of the modified polypropylene results in strong structural stability and high rigidity, which is beneficial to reducing the wear volume of the material and improving wear resistance.

Description

Technical Field

[0001] This invention relates to the field of polypropylene materials technology, specifically to a wear-resistant and crack-resistant polypropylene material and its preparation method. Background Technology

[0002] Polypropylene (PP) is non-toxic, odorless, transparent, inexpensive, chemically stable, corrosion-resistant, and has strong insulation properties, making it widely used in daily-use plastic products, building materials, and packaging materials. However, PP currently suffers from poor abrasion resistance and relatively low tear strength. Blending PP with EPDM rubber, nitrile rubber, and silicone rubber can yield high-performance rubber-plastic composites and vulcanized elastomers.

[0003] Silicone rubber possesses excellent high-temperature resistance, wear resistance, and mechanical strength, making it widely used. Patent CN110066519B discloses a silicone rubber / polypropylene thermoplastic vulcanizate and its preparation method, using the reaction product of epoxy silicone oil and polypropylene grafted with maleic anhydride as a compatibilizer. This improves the compatibility and viscosity of silicone rubber and polypropylene, enhancing the material's high-temperature resistance and mechanical properties. However, this patent does not improve the wear resistance or other properties of the polypropylene material. Summary of the Invention

[0004] This invention solves the problem of poor wear resistance and tear strength of silicone rubber-polypropylene composite materials.

[0005] The technical solution of the present invention is: a wear-resistant and crack-resistant polypropylene material and its preparation method, comprising the following components: 100 parts by weight of polypropylene resin, 2-12 parts by weight of phenylsiloxane modified polypropylene compatibilizer, 10-50 parts by weight of methyl vinyl silicone rubber, 0.06-0.28 parts by weight of vulcanizing agent, and 0.2-0.3 parts by weight of antioxidant.

[0006] The preparation method is as follows: Methyl vinyl silicone rubber and vulcanizing agent are mixed in an open mill to form a compound, which is then added to a torque rheometer. Polypropylene, phenylsiloxane-modified polypropylene compatibilizer, and antioxidant are added and mixed at 170-180℃ for 6-10 minutes. Finally, the material is placed in a flat vulcanizing machine and hot-pressed at 175-180℃ and 10-15MPa pressure for 6-8 minutes, followed by cold pressing for 3-5 minutes to obtain wear-resistant and crack-resistant polypropylene material.

[0007] Preferably, the vulcanizing agent is dicumyl peroxide or bis(2,5)-2,5-diisopropylbenzene.

[0008] Preferably, the antioxidant is antioxidant 1010, antioxidant 1076 or antioxidant 168.

[0009] Preferably, the preparation method of the phenylsiloxane-modified polypropylene compatibilizer is as follows:

[0010] (1) Add maleic anhydride-grafted polypropylene, 4-hydroxystyrene (CAS No. 2628-17-3) and p-toluenesulfonic acid to xylene, stir and react in nitrogen at 100-110℃ for 6-8h, then add p-toluenesulfonic acid and continue the reaction for 5-8h. Pour acetone into the solution to precipitate, filter the product, wash with acetone, and dry to obtain polypropylene compatibilizer precursor.

[0011] (2) Add polypropylene compatibilizer precursor, pentamethyldisiloxane (CAS No. 1438-82-0) and caster catalyst to xylene, and react in nitrogen. Pour acetone into the solution to precipitate. Filter the product and wash it with acetone and ethanol in sequence. Dry it to obtain phenylsiloxane modified polypropylene compatibilizer.

[0012]

[0013] Preferably, in (1), the amount of maleic anhydride-grafted polypropylene is 100 parts by weight, 4-hydroxystyrene is 12-16 parts by weight, and p-toluenesulfonic acid is 5-6 parts by weight.

[0014] Preferably, in (2), the amount of polypropylene compatibilizer precursor is 100 parts by weight, pentamethyldisiloxane is 14-20 parts by weight, and caster catalyst is 0.3-0.38 parts by weight.

[0015] Preferably, the reaction temperature in (2) is 80-90℃ and the reaction time is 5-7h.

[0016] The beneficial technical effects of this invention are as follows: This invention involves esterifying maleic anhydride-grafted polypropylene and 4-hydroxystyrene, followed by a hydrosilylation reaction with pentamethyldisiloxane to obtain a phenylsiloxane-modified polypropylene compatibilizer. This compatibilizer is then blended with polypropylene and methyl vinyl silicone rubber and subjected to high-temperature vulcanization to obtain a wear-resistant and crack-resistant polypropylene material. The main chain of the phenylsiloxane-modified polypropylene contains a polypropylene molecular chain, while the side chain contains the same siloxane groups as methyl vinyl silicone rubber. This results in similar polarity between the phenylsiloxane-modified polypropylene and methyl vinyl silicone rubber, allowing the phenylsiloxane-modified polypropylene to act as a compatibilizer, improving the compatibility between polypropylene and methyl vinyl silicone rubber, and enabling the material to exhibit higher mechanical properties such as tear strength. Furthermore, the introduction of a siloxane structure containing a rigid benzene ring into the side chain of the modified polypropylene provides strong structural stability and high rigidity, which helps reduce the wear volume of the material and improve its wear resistance. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] The following maleic anhydride-grafted polypropylene, grade CA 100, was purchased from Dongguan Yingsheng Plastic & Chemical Co., Ltd. The caster catalyst, CAS number 68478-92-2, was purchased from Hubei Chengfeng Chemical Co., Ltd.

[0019] Example 1

[0020] (1) Add 50g of maleic anhydride-grafted polypropylene, 6.8g (56.6mmol) of 4-hydroxystyrene and 1.6g of p-toluenesulfonic acid to 650mL of xylene. Stir the mixture at 100℃ under nitrogen for 8h. Then add 1g of p-toluenesulfonic acid and continue the reaction for 6h. Pour acetone into the solution to precipitate the product. Filter the product, wash it with acetone, and dry it to obtain the polypropylene compatibilizer precursor.

[0021] (2) Add 50g of polypropylene compatibilizer precursor, 8.2g of pentamethyldisiloxane and 0.17g of caster catalyst to 600mL of xylene. Stir the reaction in nitrogen at 80℃ for 7h. Pour acetone into the solution to precipitate. Filter the product and wash it with acetone and ethanol in sequence. Dry it to obtain phenylsiloxane modified polypropylene compatibilizer.

[0022] (3) Mix 0.5 kg of methyl vinyl silicone rubber and 3 g of vulcanizing agent dicumyl peroxide in a two-roll mill to make a compound. Then add it to a torque rheometer, add 5 kg of polypropylene resin, 100 g of phenylsiloxane modified polypropylene compatibilizer and 12 g of antioxidant 1076, and mix at 175°C for 10 min. Finally, put the material in a flat vulcanizing machine, first hot press at 180°C and 10 MPa pressure for 8 min, then cold press for 4 min, and mold to obtain wear-resistant and crack-resistant polypropylene material.

[0023] Example 2

[0024] (1) Add 50g of maleic anhydride-grafted polypropylene, 8g of 4-hydroxystyrene and 1.8g of p-toluenesulfonic acid to 800mL of xylene. Stir the mixture at 100℃ under nitrogen for 8h. Then add 1.2g of p-toluenesulfonic acid and continue the reaction for 8h. Pour acetone into the solution to precipitate the product. Filter the product, wash it with acetone and dry it to obtain the polypropylene compatibilizer precursor.

[0025] (2) Add 50g of polypropylene compatibilizer precursor, 10g of pentamethyldisiloxane and 0.19g of caster catalyst to 700mL of xylene. Stir the reaction at 90℃ for 5h under nitrogen. Pour acetone into the solution to precipitate. Filter the product and wash it with acetone and ethanol in sequence. Dry it to obtain phenylsiloxane modified polypropylene compatibilizer.

[0026] (3) Mix 1 kg of methyl vinyl silicone rubber and 6 g of vulcanizing agent bis2,5 in a two-roll mill to make a compound. Then add it to a torque rheometer, add 5 kg of polypropylene resin, 120 g of phenylsiloxane modified polypropylene compatibilizer and 15 g of antioxidant 1010, and mix them together at 170°C for 10 min. Finally, put the material in a flat vulcanizing machine, first hot press at 175°C and 15 MPa pressure for 8 min, then cold press for 5 min, and mold to obtain wear-resistant and crack-resistant polypropylene material.

[0027] Example 3

[0028] (1) Add 50g of maleic anhydride-grafted polypropylene, 6g of 4-hydroxystyrene and 1.6g of p-toluenesulfonic acid to 600mL of xylene. Stir the mixture at 110℃ under nitrogen for 6h. Then add 0.9g of p-toluenesulfonic acid and continue the reaction for 5h. Pour acetone into the solution to precipitate the product. Filter the product, wash it with acetone and dry it to obtain the polypropylene compatibilizer precursor.

[0029] (2) Add 50g of polypropylene compatibilizer precursor, 7g of pentamethyldisiloxane and 0.15g of caster catalyst to 600mL of xylene. Stir the reaction in nitrogen at 85℃ for 5h. Pour acetone into the solution to precipitate. Filter the product and wash it with acetone and ethanol in sequence. Dry it to obtain phenylsiloxane modified polypropylene compatibilizer.

[0030] (3) Mix 1.8 kg of methyl vinyl silicone rubber and 10 g of vulcanizing agent bis2,5 in a two-roll mill to make a compound. Then add it to a torque rheometer, add 5 kg of polypropylene resin, 400 g of phenylsiloxane modified polypropylene compatibilizer and 10 g of antioxidant 168, and mix at 180°C for 6 min. Finally, put the material in a flat vulcanizing machine, first hot press at 175°C and 10 MPa pressure for 8 min, then cold press for 5 min, and mold to obtain wear-resistant and crack-resistant polypropylene material.

[0031] Example 4

[0032] (1) 2.5 kg of methyl vinyl silicone rubber and 14 g of vulcanizing agent dicumyl peroxide were mixed in a two-roll mill to make a compound. Then, the compound was added to a torque rheometer, along with 5 kg of polypropylene resin, 600 g of phenylsiloxane modified polypropylene compatibilizer (prepared in Example 1), and 14 g of antioxidant 1010. The compound was mixed at 180 °C for 8 min. Finally, the material was placed in a flat vulcanizing machine and hot-pressed at 180 °C and 10 MPa for 6 min, then cold-pressed for 3 min, and molded to obtain polypropylene material.

[0033] Comparative Example 1

[0034] (1) Mix 0.5 kg of methyl vinyl silicone rubber and 3 g of vulcanizing agent dicumyl peroxide in a two-roll mill to make a compound. Then add it to a torque rheometer, add 5 kg of polypropylene resin and 12 g of antioxidant 1076, and mix at 175°C for 10 min. Finally, put the material in a flat vulcanizing machine, first hot press at 180°C and 10 MPa pressure for 8 min, then cold press for 4 min, and mold to obtain wear-resistant and crack-resistant polypropylene material.

[0035] Comparative Example 2

[0036] (1) Mix 0.5 kg of methyl vinyl silicone rubber and 3 g of vulcanizing agent dicumyl peroxide in a two-roll mill to make a compound. Then add it to a torque rheometer, add 5 kg of polypropylene resin, 100 g of maleic anhydride grafted polypropylene and 12 g of antioxidant 1076, and mix at 175 °C for 10 min. Finally, put the material in a flat vulcanizing machine, first hot press at 180 °C and 10 MPa pressure for 8 min, then cold press for 4 min, and mold to obtain polypropylene material.

[0037] Comparative Example 3

[0038] (1) Add 50g of maleic anhydride-grafted polypropylene, 4.08g (56.6mmol) of 3-butenol and 1.6g of p-toluenesulfonic acid to 650mL of xylene. Stir the mixture at 100℃ under nitrogen for 8h. Then add 1g of p-toluenesulfonic acid and continue the reaction for 6h. Pour acetone into the solution to precipitate the product. Filter the product, wash it with acetone, and dry it to obtain the polypropylene compatibilizer precursor.

[0039] (2) Add 50g of polypropylene compatibilizer precursor, 8.2g of pentamethyldisiloxane and 0.17g of caster catalyst to 600mL of xylene. Stir the reaction at 80℃ for 7h under nitrogen. Pour acetone into the solution to precipitate. Filter the product and wash it with acetone and ethanol in sequence. Dry it to obtain siloxane modified polypropylene compatibilizer.

[0040] (3) Mix 0.5 kg of methyl vinyl silicone rubber and 3 g of vulcanizing agent dicumyl peroxide in a two-roll mill to make a compound. Then add it to a torque rheometer, add 5 kg of polypropylene resin, 100 g of siloxane-modified polypropylene compatibilizer and 12 g of antioxidant 1076, and mix at 175°C for 10 min. Finally, put the material in a flat vulcanizing machine, first hot press at 180°C and 10 MPa pressure for 8 min, then cold press for 4 min, and mold to obtain polypropylene material.

[0041] Abrasion resistance of polypropylene materials was tested according to national standard GB / T 9867-2008. Tear strength was tested according to national standard GB / T 529-2008. Tensile properties were tested according to national standard GB / T 528-2009.

[0042] Table 1. Polypropylene Material Performance Tests

[0043]

[0044] Examples 1-4 involve blending and high-temperature vulcanization of polypropylene and methyl vinyl silicone rubber, followed by the addition of phenylsiloxane-modified polypropylene to obtain a wear-resistant and crack-resistant polypropylene material. The phenylsiloxane-modified polypropylene has a main chain containing polypropylene molecular chains, while its side chains contain the same siloxane groups as methyl vinyl silicone rubber. This results in similar polarity between the phenylsiloxane-modified polypropylene and methyl vinyl silicone rubber, allowing the phenylsiloxane-modified polypropylene to act as a compatibilizer, improving the compatibility between polypropylene and methyl vinyl silicone rubber, and enabling the material to exhibit higher mechanical properties such as tear strength. Furthermore, the introduction of a siloxane structure containing a rigid benzene ring into the side chain of the modified polypropylene further enhances its properties. It has strong structural stability and high rigidity, which is beneficial to improving the wear resistance of polypropylene materials and reducing the wear volume.

[0045] Comparative Example 1 did not include a phenylsiloxane-modified polypropylene compatibilizer, resulting in poor compatibility between polypropylene and methyl vinyl silicone rubber, leading to poor mechanical properties such as wear resistance and tear strength.

[0046] Comparative Example 2 used conventional maleic anhydride-grafted polypropylene as a compatibilizer. Since methyl vinyl silicone rubber does not contain active groups, it cannot react with maleic anhydride-grafted polypropylene. As a result, maleic anhydride-grafted polypropylene cannot act as a compatibilizer and it is difficult to improve the compatibility between polypropylene and methyl vinyl silicone rubber. Consequently, the mechanical properties of the material, such as wear resistance and tear strength, are poor.

[0047] Comparative Example 3 used maleic anhydride-grafted polypropylene, 3-butenol, pentamethyldisiloxane, etc. as reactants to prepare siloxane-modified polypropylene. The side chain of the prepared siloxane-modified polypropylene contained siloxane groups, which could act as compatibilizers and improve the compatibility between polypropylene and methyl vinyl silicone rubber. This was beneficial to improving the mechanical properties of the material, such as tear strength. However, the wear volume was significantly higher than that of Comparative Example 1. This may be because the side chain of the siloxane-modified polypropylene does not contain benzene ring structures with high structural stability and rigidity, which is not conducive to improving the wear resistance of the material.

Claims

1. A wear-resistant and crack-resistant polypropylene material, characterized in that, The wear-resistant and crack-resistant polypropylene material comprises the following components: 100 parts by weight of polypropylene resin, 2-12 parts by weight of phenylsiloxane modified polypropylene compatibilizer, 10-50 parts by weight of methyl vinyl silicone rubber, 0.06-0.28 parts by weight of vulcanizing agent, and 0.2-0.3 parts by weight of antioxidant. The preparation method of the phenylsiloxane-modified polypropylene compatibilizer is as follows: (1) Maleic anhydride-grafted polypropylene, 4-hydroxystyrene and p-toluenesulfonic acid were added to xylene and reacted in nitrogen. Then p-toluenesulfonic acid was added and the reaction continued. The solution was poured into acetone for precipitation. After filtration, washing and drying, polypropylene compatibilizer precursor was obtained. (2) Add polypropylene compatibilizer precursor, pentamethyldisiloxane and caster catalyst to xylene, react in nitrogen, pour the solution into acetone for precipitation, filter, wash and dry to obtain phenylsiloxane modified polypropylene compatibilizer. In (1), the amount of maleic anhydride-grafted polypropylene is 100 parts by weight, 4-hydroxystyrene is 12-16 parts by weight, and p-toluenesulfonic acid is 5-6 parts by weight. In step (2), the amount of polypropylene compatibilizer precursor is 100 parts by weight, pentamethyldisiloxane is 14-20 parts by weight, and caster catalyst is 0.3-0.38 parts by weight.

2. The wear-resistant and crack-resistant polypropylene material according to claim 1, characterized in that, The temperature of the first reaction in (1) is 100-110℃ and the reaction time is 6-8h; the reaction time of the second reaction is 5-8h.

3. The wear-resistant and crack-resistant polypropylene material according to claim 1, characterized in that, The reaction temperature in (2) is 80-90℃ and the reaction time is 5-7h.

4. The wear-resistant and crack-resistant polypropylene material according to claim 1, characterized in that, The vulcanizing agent is dicumyl peroxide or bis(2,5)-2,5-diisopropylbenzene.

5. The wear-resistant and crack-resistant polypropylene material according to claim 1, characterized in that, The antioxidant is antioxidant 1010, antioxidant 1076, or antioxidant 168.

6. A method for preparing the wear-resistant and crack-resistant polypropylene material as described in any one of claims 1-5, characterized in that, The preparation method is as follows: methyl vinyl silicone rubber and vulcanizing agent are mixed in a two-roll mill to form a compound, which is then added to a torque rheometer, and polypropylene, phenylsiloxane-modified polypropylene compatibilizer, and antioxidant are added for blending. Finally, the material is molded in a flat vulcanizing machine to obtain wear-resistant and crack-resistant polypropylene material.

7. The method for preparing the wear-resistant and crack-resistant polypropylene material according to claim 6, characterized in that, The blending temperature is 170-180℃ and the time is 6-10 min; the compression molding is first hot-pressed at 175-180℃ and 10-15MPa pressure for 6-8 min, and then cold-pressed for 3-5 min.

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