High-strength polypropylene composite material, preparation method and application of high-strength polypropylene composite material in automobile bumpers

Abstract

The invention relates to the technical field of polypropylene, and discloses a high-strength polypropylene composite material as well as a preparation method and application thereof in an automobile bumper. The high-strength polypropylene composite material comprises the following components in parts by weight: 70-90 parts of polypropylene resin, 10-30 parts of polycarbonate resin, 25-40 parts of glass fibers, 3-10 parts of an allyl carbonate grafted polypropylene compatilizer and the like. The compatilizer contains carbonate groups similar to polycarbonate, so that the compatibility between polypropylene resin and polycarbonate resin is improved, and the compatilizer has higher mechanical properties. Moreover, the compatilizer contains carboxyl and can form interaction with the surface of the glass fiber, so that the compatibility between the glass fiber and the polypropylene resin is improved, the glass fiber has a better reinforcing effect, the tensile strength, the impact strength and the bending strength of the composite material are remarkably improved, and the compatilizer has good practical application in the aspects of automobile bumpers and the like.

Description

Technical Field

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

[0002] The bumper is one of the important safety devices of an automobile, which plays a role in absorbing and reducing the external impact force and protecting the safety of the vehicle body. Its materials mainly include polypropylene, polycarbonate, ABS plastic, etc. Among them, polypropylene has the advantages of light weight, high weather resistance, high impact resistance, etc., and is widely used in automotive materials such as bumpers. Usually, toughening agents, reinforcing agents, etc. need to be added to improve the mechanical strength and other properties of polypropylene to meet its actual application in the bumper.

[0003] Glass fiber has good heat resistance, corrosion resistance, and mechanical strength, and is widely used in plastics such as polypropylene and polycarbonate. Usually, a compatibilizer needs to be added to improve its compatibility with high molecular resins. Blending polypropylene and polycarbonate can produce a plastic alloy material with excellent properties. Chinese Patent with Publication No. CN117603568B discloses a high-strength tensile-resistant packaging bag and its production process, which uses polycarbonate, polypropylene, modified loaded glass fiber, etc. as raw materials. The prepared packaging bag has properties such as high strength, rigidity, and degradability, but the packaging bag does not show good bending strength, impact strength, etc., which is not conducive to the actual application of polypropylene and polycarbonate composite materials in high-performance bumpers. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a high-strength polypropylene composite material, a preparation method thereof, and an application thereof in an automobile bumper, which solves the problem of poor compatibility between polypropylene, polycarbonate, and glass fiber, and improves the mechanical strength of polypropylene materials.

[0005] 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 includes 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 as follows: (1) In an ice-water bath, add dichloromethane, glycolic acid, allyl chloroformate, and a catalyst to a reaction vessel, stir and react, then distill under reduced pressure, and purify the crude product by column chromatography to obtain allyl carbonate monomer. The reaction formula is: .

[0006] (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, then add acetone for precipitation. Wash with acetone after filtration and dry to obtain an allyl carbonate grafted polypropylene compatibilizer.

[0007] (3) Mix polypropylene resin, polycarbonate resin, glass fiber, allyl carbonate grafted polypropylene compatibilizer, and antioxidant, and melt extrude and pelletize in a twin-screw extruder to obtain a high-strength polypropylene composite material.

[0008] Preferably, the antioxidant is antioxidant 1010, antioxidant 1076, or antioxidant 330.

[0009] Preferably, in (1), the dosage of glycolic acid is 100 parts by weight, the dosage of allyl chloroformate is 220 - 280 parts by weight, and the dosage of the catalyst is 225 - 290 parts by weight.

[0010] Preferably, the catalyst is N,N-dimethylaniline or N,N-dimethylbenzylamine.

[0011] Preferably, in (1), the reaction temperature is 15 - 25 °C and the reaction time is 2 - 4 h.

[0012] Preferably, in (2), the dosage of polypropylene resin is 100 parts by weight, the dosage of allyl carbonate monomer is 3 - 12 parts by weight, and the dosage of diisopropylbenzene peroxide is 0.6 - 1.2 parts by weight.

[0013] Preferably, in (2), the melt grafting temperature is 185 - 200 °C.

[0014] Preferably, in (3) during melt extrusion, the temperature of zones 1 - 6 of the twin-screw extruder is 180 °C - 260 °C.

[0015] Preferably, the high-strength polypropylene composite material is applied to automotive bumpers.

[0016] By adopting the above technical solution, the beneficial technical effects are as follows: The polypropylene is melt grafted with the vinyl group of the allyl carbonate monomer to obtain an allyl carbonate grafted polypropylene compatibilizer, and then it is melt blended with polypropylene resin, polycarbonate, and glass fiber to obtain a high-strength polypropylene composite material. This compatibilizer uses polypropylene as the main chain, and a molecular chain of allyl carbonate polymer containing carboxyl groups is introduced into the side chain, which contains carbonate groups similar to those of polycarbonate, thereby improving the compatibility between polypropylene resin and polycarbonate resin. The two form a high-performance plastic alloy with higher mechanical properties.

[0017] The allyl carbonate grafted polypropylene compatibilizer of the present invention contains carboxyl groups, which can form interactions with the surface of glass fibers, play a compatibilizing role, improve the compatibility between glass fibers and polypropylene resin, enable glass fibers to have a better reinforcing effect, significantly improve the tensile strength, impact strength and flexural strength of the composite material, and has good practical applications in aspects such as automobile bumpers. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is the infrared spectrum of the allyl carbonate grafted polypropylene compatibilizer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The concept of the present application and the technical effects produced will be clearly and completely described below in conjunction with the embodiments to fully understand the purpose, features and effects of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, other embodiments obtained by those skilled in the art without creative efforts shall fall within the scope of protection of the present application.

[0020] The polypropylene resin grade is F40 - 03mm, sourced from Shanghai Liuzhangyang Plasticizing Co., Ltd. The polycarbonate resin grade is 1303 - 10, from Dongguan Junyi Plastic Raw Materials Co., Ltd. The glass fiber model is tc - 008, sourced from Shandong Taicheng Fiber Co., Ltd.

[0021] Example 1: (1) In an ice - water bath, add 600 mL of dichloromethane, 20 g of glycolic acid, 52 g of allyl chloroformate, and 53 g of catalyst N,N - dimethylaniline to the reaction vessel. Remove the ice - water bath and stir at 25 °C for 2 h. Perform vacuum distillation, and purify the crude product by column chromatography, eluting with a mixed solution of petroleum ether and ethyl acetate to obtain the allyl carbonate monomer, with a yield of 25.7 g, a colorless and transparent liquid.

[0022] (2) Add 500 g of polypropylene resin, 40 g of allyl carbonate monomer, and 4.8 g of diisopropylbenzene peroxide to a twin - screw extruder, and perform melt grafting at 190 °C. After extrusion, add the product to xylene, heat to 140 °C, stir, add acetone for precipitation, wash with acetone after filtration, and dry to obtain the allyl carbonate grafted polypropylene compatibilizer. Figure 1 In the infrared spectrum of, 2927 cm -1 , 2851 cm -1 are the absorption peaks of - CH3 and - CH2 - in the polypropylene molecular chain, 3350 cm -1 is the absorption peak of - OH of the carboxyl group, and 1703 - 1726 cm -1 is the absorption peak of - C = O - in the carbonate and carboxyl groups.

[0023] (3) Mix 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, and melt-extrude them in a twin-screw extruder. The temperatures in zones 1-6 are 180 °C, 210 °C, 235 °C, 250 °C, 260 °C, and 260 °C. Pelletize to obtain a high-strength polypropylene composite material.

[0024] Example 2: (1) In an ice-water bath, add 700 mL of dichloromethane, 20 g of glycolic acid, 56 g of allyl chloroformate, and 58 g of catalyst N,N-dimethylaniline to a reaction vessel. Remove the ice-water bath and stir at 15 °C for 4 h. Perform vacuum distillation. Purify the crude product by column chromatography and elute with a mixed solution of petroleum ether and ethyl acetate to obtain allyl carbonate monomer with a yield of 23.5 g, which is a colorless transparent liquid.

[0025] (2) Add 500 g of polypropylene resin, 60 g of allyl carbonate monomer, and 6 g of diisopropylbenzene peroxide to a twin-screw extruder and perform melt grafting at 185 °C. After extrusion, add the product to xylene, heat to 140 °C, stir, add acetone for precipitation, wash with acetone after filtration, and dry to obtain an allyl carbonate grafted polypropylene compatibilizer.

[0026] (3) Mix 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, and melt-extrude them in a twin-screw extruder. The temperatures in zones 1-6 are 180 °C, 210 °C, 235 °C, 250 °C, 260 °C, and 260 °C. Pelletize to obtain a high-strength polypropylene composite material.

[0027] Example 3: (1) In an ice-water bath, add 600 mL of dichloromethane, 20 g of glycolic 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. Perform vacuum distillation. Purify the crude product by column chromatography and elute with a mixed solution of petroleum ether and ethyl acetate to obtain allyl carbonate monomer with a yield of 26.8 g, which is a colorless transparent liquid.

[0028] (2) Add 500 g of polypropylene resin, 15 g of allyl carbonate monomer, and 3 g of diisopropylbenzene peroxide to a twin-screw extruder and perform melt grafting at 200 °C. After extrusion, add the product to xylene, heat to 130 °C, stir, add acetone for precipitation, wash with acetone after filtration, and dry to obtain an allyl carbonate grafted polypropylene compatibilizer.

[0029] (3) Mix 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, and melt-extrude in a twin-screw extruder. The temperatures in zones 1-6 are 180 °C, 210 °C, 235 °C, 250 °C, 260 °C, and 260 °C, and pelletize to obtain a high-strength polypropylene composite material.

[0030] Comparative Example 1 (1) Mix 9 kg of polypropylene resin, 1 kg of polycarbonate resin, 2.5 kg of glass fiber, and 35 g of antioxidant 330, and melt-extrude in a twin-screw extruder. The temperatures in zones 1-6 are 180 °C, 210 °C, 235 °C, 250 °C, 260 °C, and 260 °C, and pelletize to obtain a polypropylene composite material.

[0031] Comparative Example 2 (1) Add 500 g of polypropylene resin, 40 g of acrylic acid, and 4.8 g of diisopropylbenzene peroxide to a twin-screw extruder, and perform melt grafting at 190 °C. After extrusion, add the product to xylene, heat to 140 °C, stir, add acetone for precipitation, wash with acetone after filtration, and dry to obtain an acrylic acid grafted polypropylene compatibilizer.

[0032] (2) Mix 9 kg of polypropylene resin, 1 kg of polycarbonate resin, 2.5 kg of glass fiber, 0.3 kg of acrylic acid grafted polypropylene compatibilizer, and 35 g of antioxidant 330, and melt-extrude in a twin-screw extruder. The temperatures in zones 1-6 are 180 °C, 210 °C, 235 °C, 250 °C, 260 °C, and 260 °C, and pelletize to obtain a polypropylene composite material.

[0033] Comparative Example 3 (1) Add 500 g of polypropylene resin, 40 g of allyl methyl carbonate (CAS No. 35466-83-2), and 4.8 g of diisopropylbenzene peroxide to a twin-screw extruder, and perform melt grafting at 190 °C. After extrusion, add the product to xylene, heat to 140 °C, stir, add acetone for precipitation, wash with acetone after filtration, and dry to obtain an allyl methyl carbonate grafted polypropylene compatibilizer.

[0034] (2) Mix 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, and melt-extrude in a twin-screw extruder. The temperatures in zones 1-6 are 180 °C, 210 °C, 235 °C, 250 °C, 260 °C, and 260 °C, and pelletize to obtain a polypropylene composite material.

[0035] Comparative Example 4 (1) Add 500 g of polypropylene resin, 40 g of maleic anhydride, and 4.8 g of diisopropylbenzene peroxide into a twin-screw extruder, and conduct melt grafting at 190 °C. After extrusion, add the product into xylene, heat to 140 °C, stir, add acetone for precipitation, wash with acetone after filtration, and dry to obtain a maleic anhydride-grafted polypropylene compatibilizer.

[0036] (2) Mix 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, and conduct melt extrusion in a twin-screw extruder. The temperatures in zones 1-6 are 180 °C, 210 °C, 235 °C, 250 °C, 260 °C, and 260 °C, and pelletize to obtain a polypropylene composite material.

[0037] Inject the polypropylene composite material into test specimens through an injection molding machine. The tensile strength is tested according to the standard of GB / T 1040.1-2018. The Izod impact strength is tested according to the standard of GB / T 1843-2008. The flexural strength is tested according to the standard of GB / T 9341-2000.

[0038] Table 1 Strength Test of Polypropylene Composite Material 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 After testing, in Comparative Example 1, polypropylene resin, polycarbonate, and glass fiber are melt-blended, and the compatibility among them is poor, resulting in low tensile strength, impact strength, and flexural strength of the composite material.

[0039] In the composite materials of Examples 1-3, allyl carbonate-grafted polypropylene is added as a compatibilizer. It uses polypropylene as the main chain, and a polymer molecular chain of allyl carbonate containing a carboxyl group is introduced into the side chain, containing a carbonate group similar to that of polycarbonate ( ), thereby improving the compatibility between polypropylene resin and polycarbonate resin. At the same time, the carboxyl group contained can form an interaction with the surface of glass fiber, playing a role in compatibilization, improving 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 glass fiber has a better reinforcing effect. Under the synergistic effect, the tensile strength, impact strength, and flexural strength of the composite material are significantly improved.

[0040] In Comparative Example 2, conventional acrylic-grafted polypropylene is used as a compatibilizer, which is difficult to improve the compatibility between polycarbonate resin and polypropylene resin, resulting in low mechanical properties such as tensile strength of the composite material.

[0041] In Comparative Example 3, allyl methyl carbonate grafted polypropylene was used as a compatibilizer, and it was difficult to improve the compatibility between glass fiber and polypropylene resin, resulting in low mechanical properties such as the tensile strength of the composite material.

[0042] In Comparative Example 4, conventional maleic anhydride grafted polypropylene was used as a compatibilizer, and the properties such as the tensile strength of the obtained composite material were also significantly lower than those of each example.

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, add dichloromethane, glycolic acid, allyl chloroformate, and a catalyst into a reaction vessel, stir and react, then perform reduced pressure distillation. The crude product is separated and purified by column chromatography to obtain allyl carbonate monomer; (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, then add acetone for precipitation. Filter, wash, and dry to obtain the allyl carbonate grafted polypropylene compatibilizer.

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 dosage of glycolic acid is 100 parts by weight, the dosage of allyl chloroformate is 220-280 parts by weight, and the dosage 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 In the above (1), the reaction temperature is 15-25 °C, and the reaction time is 2-4 h.

6. The high-strength polypropylene composite material according to claim 1, wherein In the above (2), the dosage of polypropylene resin is 100 parts by weight, the dosage of allyl carbonate monomer is 3-12 parts by weight, and the dosage of diisopropylbenzene peroxide is 0.6-1.2 parts by weight.

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

8. A method for preparing a high-strength polypropylene composite material according to any one of claims 1-7, characterized in that, The preparation method is: mix polypropylene resin, polycarbonate resin, glass fiber, allyl carbonate grafted polypropylene compatibilizer, and antioxidant, and perform melt extrusion and pelletizing in a twin-screw extruder to obtain the high-strength polypropylene composite material.

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

10. Application of a high-strength polypropylene composite material obtained by the preparation method as claimed in claim 9 in an automobile bumper.

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