A high-strength polypropylene composite material and its preparation method and its application in automobile bumper

Abstract

The present invention relates to the field of polypropylene technology, and discloses a high-strength polypropylene composite material and preparation method and application in automobile bumper, 70-90 parts by weight of polypropylene resin, 10-30 parts by weight of polycarbonate resin, 25-40 parts by weight of glass fiber, 3-10 parts by weight of allyl carbonate grafted polypropylene compatibilizer etc. The compatibilizer contains a carbonate group similar to polycarbonate, improves the compatibility between polypropylene resin and polycarbonate resin, and has higher mechanical properties. And the compatibilizer contains a carboxyl group, can form an interaction with the glass fiber surface, improves the compatibility between glass fiber and polypropylene resin, makes glass fiber have better reinforcement, significantly improves the tensile strength, impact strength and flexural strength of composite material, and has good practical application in aspects such as automobile bumper.

Description

Technical Field

[0001] The present invention relates to the technical field of polypropylene, in particular to a high-strength polypropylene composite material, a preparation method thereof and application in automobile bumpers. Background Art

[0002] Bumpers are a key automotive safety feature, absorbing and mitigating external impacts to protect the vehicle. They are primarily made of polypropylene, polycarbonate, and ABS plastic. Polypropylene, with its advantages of lightweight, high weather resistance, and high impact resistance, is widely used in bumpers and other automotive applications. Tougheners and reinforcing agents are often added to enhance the mechanical strength and other properties of polypropylene to meet its practical application in bumpers.

[0003] Glass fibre has good heat resistance, corrosion resistance, mechanical strength, is widely used in plastics such as polypropylene, polycarbonate, and usually needs to add compatibilizer, to improve the compatibility between itself and the polymer resin. Polypropylene and polycarbonate are blended, and can be made into plastic alloy material with excellent performance. Announcement number is that the Chinese patent of CN117603568B discloses a kind of high-strength anti-tensile packaging bag and production technology thereof, with polycarbonate, polypropylene, modified loaded glass fibre etc. as raw material, the packaging bag of preparation has higher intensity, rigidity and performances such as degradable, but this packaging bag does not show performances such as good flexural strength, impact strength, is unfavorable for the practical application of polypropylene and polycarbonate composite material in high-performance bumper. Summary of the Invention

[0004] In response to the deficiencies of the prior art, the present invention provides a high-strength polypropylene composite material, a preparation method, and its application in automobile bumpers, which solves the problem of poor compatibility between polypropylene, polycarbonate, and glass fiber, and improves the mechanical strength of the polypropylene material.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a high-strength polypropylene composite material and a preparation method, the polypropylene composite material comprises 70-90 parts by weight of polypropylene, 10-30 parts by weight of polycarbonate resin, 25-40 parts by weight of glass fiber, 3-10 parts by weight of allyl carbonate grafted polypropylene compatibilizer, and 0.2-0.35 parts by weight of antioxidant. The preparation method of the polypropylene composite material is:

[0006] (1) In an ice-water bath, add dichloromethane, glycolic acid, allyl chloroformate, and a catalyst to a reaction vessel, stir the reaction, and then distill under reduced pressure. The crude product is separated and purified by column chromatography to obtain an allyl carbonate monomer. The reaction formula is:

[0007] .

[0008] (2) Add polypropylene resin, allyl carbonate monomer, and diisopropylbenzene peroxide into a twin-screw extruder for melt grafting. After extrusion, add the product into xylene, heat and stir, add acetone for precipitation, filter, wash with acetone, and dry to obtain an allyl carbonate grafted polypropylene compatibilizer.

[0009] (3) Polypropylene resin, polycarbonate resin, glass fiber, allyl carbonate grafted polypropylene compatibilizer, and antioxidant are mixed, melt-extruded in a twin-screw extruder, and pelletized to obtain a high-strength polypropylene composite material.

[0010] Preferably, the antioxidant is antioxidant 1010, antioxidant 1076 or antioxidant 330.

[0011] Preferably, in (1), the amount of glycolic acid is 100 parts by weight, the amount of allyl chloroformate is 220-280 parts by weight, and the amount of the catalyst is 225-290 parts by weight.

[0012] Preferably, the catalyst is N,N-dimethylaniline or N,N-dimethylbenzylamine.

[0013] Preferably, the reaction temperature in (1) is 15-25°C and the reaction time is 2-4 hours.

[0014] Preferably, in (2), the amount of polypropylene resin used is 100 parts by weight, the amount of allyl carbonate monomer used is 3-12 parts by weight, and the amount of dicumyl peroxide used is 0.6-1.2 parts by weight.

[0015] Preferably, in (2), the temperature of the melt grafting is 185-200°C.

[0016] Preferably, during the melt extrusion in (3), the temperature of zones 1-6 of the twin-screw extruder is 180°C-260°C.

[0017] Preferably, the high-strength polypropylene composite material is used in automobile bumpers.

[0018] The above technical solution produces the following beneficial technical effects: The alkenyl groups of allyl carbonate monomers are melt-grafted onto polypropylene to produce an allyl carbonate-grafted polypropylene compatibilizer, which is then melt-blended with polypropylene resin, polycarbonate, and glass fiber to produce a high-strength polypropylene composite material. The compatibilizer has polypropylene as its backbone and carboxyl-containing allyl carbonate polymer molecular chains introduced into its side chains. These carbonate groups, similar to those in polycarbonate, enhance the compatibility between the polypropylene resin and the polycarbonate resin, resulting in a high-performance plastic alloy with enhanced mechanical properties.

[0019] The allyl carbonate grafted polypropylene compatibilizer of the present invention contains carboxyl groups, can interact with the surface of glass fibers, play a compatibilizing role, improve the compatibility between glass fibers and polypropylene resin, make the glass fibers have a better reinforcement effect, and significantly improve the tensile strength, impact strength and flexural strength of the composite material. It has good practical application in automobile bumpers and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the infrared spectrum of allyl carbonate grafted polypropylene compatibilizer. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the concept and technical effects of this application in conjunction with the embodiments to fully understand the purpose, features and effects of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of this application.

[0022] Polypropylene resin, grade F40-03mm, was sourced from Shanghai Liu Zhangyang Plastics Co., Ltd. Polycarbonate resin, grade 1303-10, was sourced from Dongguan Junyi Plastic Materials Co., Ltd. Glass fiber, model tc-008, was sourced from Shandong Taicheng Fiber Co., Ltd.

[0023] Example 1:

[0024] (1) In an ice-water bath, add 600 mL of dichloromethane, 20 g of hydroxyacetic acid, 52 g of allyl chloroformate, and 53 g of catalyst N,N-dimethylaniline to a reaction vessel. Remove the ice-water bath, stir at 25 °C for 2 h, and distill under reduced pressure. The crude product is separated and purified by column chromatography and eluted with a mixed solution of petroleum ether and ethyl acetate to obtain 25.7 g of allyl carbonate monomer as a colorless transparent liquid.

[0025] (2) 500 g of polypropylene resin, 40 g of allyl carbonate monomer, and 4.8 g of diisopropylbenzene peroxide were added to a twin-screw extruder and melt grafted at 190 °C. After extrusion, the product was added to xylene, heated to 140 °C, stirred, and then precipitated with acetone. After filtering, the product was washed with acetone and dried to obtain an allyl carbonate grafted polypropylene compatibilizer. Figure 1 In the infrared spectrum, 2927 cm -1 、2851cm -1 It is the absorption peak of -CH3 and -CH2- in the polypropylene molecular chain, 3350cm -1 It is the absorption peak of -OH of carboxyl group, 1703-1726cm -1 It is the absorption peak of -C=O- in carbonate and carboxyl groups.

[0026] (3) 9 kg of polypropylene resin, 1 kg of polycarbonate resin, 2.5 kg of glass fiber, 0.3 kg of allyl carbonate grafted polypropylene compatibilizer, and 35 g of antioxidant 330 were mixed and melt-extruded in a twin-screw extruder. The temperatures in zones 1-6 were 180°C, 210°C, 235°C, 250°C, 260°C, and 260°C. The mixture was pelletized to obtain a high-strength polypropylene composite material.

[0027] Example 2:

[0028] (1) In an ice-water bath, add 700 mL of dichloromethane, 20 g of hydroxyacetic acid, 56 g of allyl chloroformate, and 58 g of catalyst N,N-dimethylaniline to a reaction vessel. Remove the ice-water bath, stir at 15°C for 4 h, and distill under reduced pressure. The crude product is separated and purified by column chromatography and eluted with a mixed solution of petroleum ether and ethyl acetate to obtain 23.5 g of allyl carbonate monomer as a colorless transparent liquid.

[0029] (2) Add 500 g of polypropylene resin, 60 g of allyl carbonate monomer, and 6 g of diisopropylbenzene peroxide into a twin-screw extruder and perform melt grafting at 185 °C. After extrusion, add the product into xylene, heat to 140 °C, stir, and then add acetone for precipitation. After filtering, wash with acetone, and dry to obtain an allyl carbonate grafted polypropylene compatibilizer.

[0030] (3) 8 kg of polypropylene resin, 2 kg of polycarbonate resin, 3.3 kg of glass fiber, 0.7 kg of allyl carbonate grafted polypropylene compatibilizer, and 30 g of antioxidant 1076 were mixed and melt-extruded in a twin-screw extruder. The temperatures in zones 1-6 were 180°C, 210°C, 235°C, 250°C, 260°C, and 260°C. The mixture was pelletized to obtain a high-strength polypropylene composite material.

[0031] Example 3:

[0032] (1) In an ice-water bath, add 600 mL of dichloromethane, 20 g of hydroxyacetic acid, 44 g of allyl chloroformate, and 45 g of N,N-dimethylbenzylamine to a reaction vessel. Remove the ice-water bath and stir at 20°C for 4 h. Distill under reduced pressure. The crude product is separated and purified by column chromatography and eluted with a mixed solution of petroleum ether and ethyl acetate to obtain 26.8 g of allyl carbonate monomer as a colorless, transparent liquid.

[0033] (2) Add 500 g of polypropylene resin, 15 g of allyl carbonate monomer, and 3 g of diisopropylbenzene peroxide into a twin-screw extruder and perform melt grafting at 200 °C. After extrusion, add the product into xylene, heat to 130 °C, stir, and then add acetone for precipitation. After filtering, wash with acetone, and dry to obtain an allyl carbonate grafted polypropylene compatibilizer.

[0034] (3) 7 kg of polypropylene resin, 3 kg of polycarbonate resin, 4 kg of glass fiber, 1 kg of allyl carbonate grafted polypropylene compatibilizer, and 20 g of antioxidant 1010 were mixed and melt-extruded in a twin-screw extruder. The temperatures in zones 1-6 were 180°C, 210°C, 235°C, 250°C, 260°C, and 260°C. The mixture was pelletized to obtain a high-strength polypropylene composite material.

[0035] Comparative Example 1

[0036] (1) 9 kg of polypropylene resin, 1 kg of polycarbonate resin, 2.5 kg of glass fiber, and 35 g of antioxidant 330 were mixed and melt-extruded in a twin-screw extruder. The temperatures in zones 1-6 were 180°C, 210°C, 235°C, 250°C, 260°C, and 260°C. The mixture was pelletized to obtain a polypropylene composite material.

[0037] Comparative Example 2

[0038] (1) 500 g of polypropylene resin, 40 g of acrylic acid, and 4.8 g of diisopropylbenzene peroxide were added to a twin-screw extruder and melt grafted at 190 °C. After extrusion, the product was added to xylene, heated to 140 °C, stirred, and then precipitated with acetone. After filtering, the product was washed with acetone and dried to obtain an acrylic acid grafted polypropylene compatibilizer.

[0039] (2) 9 kg of polypropylene resin, 1 kg of polycarbonate resin, 2.5 kg of glass fiber, 0.3 kg of acrylic grafted polypropylene compatibilizer, and 35 g of antioxidant 330 were mixed and melt-extruded in a twin-screw extruder. The temperatures in zones 1-6 were 180°C, 210°C, 235°C, 250°C, 260°C, and 260°C. The mixture was pelletized to obtain a polypropylene composite material.

[0040] Comparative Example 3

[0041] (1) 500 g of polypropylene resin, 40 g of allyl methyl carbonate (CAS No. 35466-83-2), and 4.8 g of diisopropylbenzene peroxide were added to a twin-screw extruder and melt grafted at 190 °C. After extrusion, the product was added to xylene, heated to 140 °C, stirred, and then precipitated with acetone. After filtering, the product was washed with acetone and dried to obtain an allyl methyl carbonate grafted polypropylene compatibilizer.

[0042] (2) 9 kg of polypropylene resin, 1 kg of polycarbonate resin, 2.5 kg of glass fiber, 0.3 kg of allyl methyl carbonate grafted polypropylene compatibilizer, and 35 g of antioxidant 330 were mixed and melt-extruded in a twin-screw extruder. The temperatures in zones 1-6 were 180°C, 210°C, 235°C, 250°C, 260°C, and 260°C. The mixture was pelletized to obtain a polypropylene composite material.

[0043] Comparative Example 4

[0044] (1) 500 g of polypropylene resin, 40 g of maleic anhydride, and 4.8 g of diisopropylbenzene peroxide were added to a twin-screw extruder and melt grafted at 190 °C. After extrusion, the product was added to xylene, heated to 140 °C, stirred, and then precipitated with acetone. After filtering, the product was washed with acetone and dried to obtain a maleic anhydride grafted polypropylene compatibilizer.

[0045] (2) 9 kg of polypropylene resin, 1 kg of polycarbonate resin, 2.5 kg of glass fiber, 0.3 kg of maleic anhydride grafted polypropylene compatibilizer, and 35 g of antioxidant 330 were mixed and melt-extruded in a twin-screw extruder. The temperatures in zones 1-6 were 180°C, 210°C, 235°C, 250°C, 260°C, and 260°C. The mixture was pelletized to obtain a polypropylene composite material.

[0046] Polypropylene composite materials were injection molded into test specimens. Tensile strength was tested according to GB / T 1040.1-2018. Izod impact strength was tested according to GB / T 1843-2008. Flexural strength was tested according to GB / T 9341-2000.

[0047] Table 1 Strength test of polypropylene composite materials

[0048] Tensile strength (MPa) <![CDATA[Impact strength (kJ / m 2 )]]> Flexural strength (MPa) Example 1 44.1 16.7 50.8 Example 2 56.9 27.2 58.0 Example 3 59.3 21.4 47.6 Comparative Example 1 32.9 9.4 39.5 Comparative Example 2 38.5 12.8 45.1 Comparative Example 3 36.3 11.0 43.7 Comparative Example 4 41.4 14.2 47.5

[0049] After testing, it was found that in Comparative Example 1, polypropylene resin, polycarbonate and glass fiber were melt-blended, and the compatibility among the three was poor, resulting in low tensile strength, impact strength and flexural strength of the composite material.

[0050] Allyl carbonate grafted polypropylene was added to the composite material of Example 1-3 as a compatibilizer. The composite material has polypropylene as the main chain and an allyl carbonate polymer molecular chain containing a carboxyl group is introduced into the side chain. The composite material contains carbonate groups similar to polycarbonate ( ), thereby improving the compatibility between polypropylene resin and polycarbonate resin. At the same time, the carboxyl group contained in it can interact with the surface of glass fiber, play a role of volume expansion, and improve the compatibility between glass fiber and polypropylene resin, so that polycarbonate resin and glass fiber are evenly dispersed in the polypropylene resin matrix. Polypropylene and polycarbonate form a high-performance plastic alloy, and the glass fiber has a better reinforcement effect. Under the synergistic effect, the tensile strength, impact strength and flexural strength of the composite material are significantly improved.

[0051] In Comparative Example 2, conventional acrylic acid grafted polypropylene is used as a compatibilizer, which makes it difficult to improve the compatibility between the polycarbonate resin and the polypropylene resin, resulting in lower mechanical properties such as tensile strength of the composite material.

[0052] Comparative Example 3 uses allyl methyl carbonate grafted polypropylene as a compatibilizer, which is difficult to improve the compatibility between the glass fiber and the polypropylene resin, resulting in lower mechanical properties such as tensile strength of the composite material.

[0053] Comparative Example 4 uses conventional maleic anhydride grafted polypropylene as the compatibility, and the tensile strength and other properties of the obtained composite material are also significantly lower than those of the embodiments.

Claims

1. A high-strength polypropylene composite material, characterized in that: The high-strength polypropylene composite material comprises 70-90 parts by weight of polypropylene resin, 10-30 parts by weight of polycarbonate resin, 25-40 parts by weight of glass fiber, 3-10 parts by weight of allyl carbonate grafted polypropylene compatibilizer, and 0.2-0.35 parts by weight of antioxidant; The preparation method of the allyl carbonate grafted polypropylene compatibilizer comprises: (1) In an ice-water bath, dichloromethane, glycolic acid, allyl chloroformate, and a catalyst are added to a reaction vessel, stirred for reaction, and then distilled under reduced pressure. The crude product is separated and purified by column chromatography to obtain an allyl carbonate monomer; (2) Adding polypropylene resin, allyl carbonate monomer, and diisopropylbenzene peroxide into a twin-screw extruder for melt grafting, adding the product into xylene after extrusion, heating and stirring, adding acetone for precipitation, filtering, washing, and drying to obtain an allyl carbonate grafted polypropylene compatibilizer; In the above (2), the amount of polypropylene resin used is 100 parts by weight, the amount of allyl carbonate monomer used is 3-12 parts by weight, and the amount of dicumyl peroxide used is 0.6-1.2 parts by weight.

2. The high-strength polypropylene composite material according to claim 1, characterized in that: The antioxidant is antioxidant 1010, antioxidant 1076 or antioxidant 330.

3. The high-strength polypropylene composite material according to claim 1, characterized in that: In the above (1), the amount of glycolic acid is 100 parts by weight, the amount of allyl chloroformate is 220-280 parts by weight, and the amount of the catalyst is 225-290 parts by weight.

4. The high-strength polypropylene composite material according to claim 3, characterized in that: The catalyst is N,N-dimethylaniline or N,N-dimethylbenzylamine.

5. The high-strength polypropylene composite material according to claim 1, characterized in that: The reaction temperature in (1) is 15-25°C and the reaction time is 2-4h.

6. The high-strength polypropylene composite material according to claim 1, characterized in that: In the above (2), the temperature of melt grafting is 185-200°C.

7. A method for preparing the high-strength polypropylene composite material according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: mixing polypropylene resin, polycarbonate resin, glass fiber, allyl carbonate grafted polypropylene compatibilizer and antioxidant, melting and extruding in a twin-screw extruder, and pelletizing to obtain a high-strength polypropylene composite material.

8. The method for preparing a high-strength polypropylene composite material according to claim 7, characterized in that: During the melt extrusion, the temperature of zones 1-6 of the twin-screw extruder is 180°C-260°C.

9. Use of the high-strength polypropylene composite material obtained by the preparation method according to claim 8 in automobile bumpers.

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