Lightweight automobile bumper and preparation method thereof

Abstract

The invention discloses a light-weight automobile bumper and a preparation method thereof. The light-weight automobile bumper is prepared from the following raw materials in parts by weight: 45-70 parts of polypropylene resin and 5-20 parts of polyhexamethylene adipamide. 25 to 40 parts of carbon fiber; 0.05 to 0.1 part of graphene; 0.5 to 2 parts of an antioxidant; 0.2 to 2 parts of pigment; 1-5 parts of a compatilizer; the density of the light-weight automobile bumper is 1.0-1.2 g / cm < 3 >, the bending modulus is 11.5-15.0 GPa, the impact strength is 9.5-11.0 kJ / m < 2 >, and the tensile strength is 83-105 MPa, and the light-weight automobile bumper has the characteristics of light weight and proper strength and toughness, has good rigidity and toughness, and can reduce the injury to pedestrians to the greatest extent during collision.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile bumpers, and in particular relates to a lightweight automobile bumper and a preparation method thereof. Background Art

[0002] The car bumper is an important safety device that mainly absorbs and mitigates external impact, protects the car body, and protects the safety of passengers and pedestrians. Car bumpers are usually made of plastic through injection molding. The bumper protects the front and rear body of the car, especially in the event of an accident with pedestrians, it can effectively protect pedestrians. Secondly, the bumper is also decorative and has become an important part of decorating the appearance of the car.

[0003] Ordinary bumpers are made of talcum powder and glass fiber reinforced polypropylene materials. The molded products have disadvantages such as heavy weight and low strength. They cannot effectively protect drivers and passengers when the vehicle collides, and are not in line with the development trend of lightweight automobiles.

[0004] Chinese patent CN110041700A discloses a carbon fiber reinforced nylon material and raw materials, preparation method and application thereof, which is prepared by blending nylon, carbon fiber, isocyanate compound with functional group 2, polycarbodiimide, antioxidant and lubricant, and has good fatigue resistance and mechanical strength. However, the carbon fiber reinforced nylon material disclosed in this patent has strong rigidity and toughness. If this material is used to prepare a car bumper, its too strong rigidity is not conducive to the protection of pedestrians, and pedestrians may be seriously injured in the event of a collision; and the density of the nylon material is also relatively large, which does not meet the requirements of lightweight car bumpers. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a lightweight automobile bumper and a preparation method thereof, wherein the density of the lightweight automobile bumper is 1.0 to 1.2 g / cm 3 The bending modulus is 11.5~15.0GPa, the impact strength is 9.5~11.0kJ / ㎡, and the tensile strength is 83~105MPa. It has the characteristics of lightweight, appropriate strength and toughness. While having good rigidity and toughness, it can minimize the damage to pedestrians in the event of a collision.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A lightweight automobile bumper is prepared from the following raw materials and parts by weight: 45-70 parts of polypropylene resin, 5-20 parts of polyhexamethylene adipamide, 25-40 parts of carbon fiber, 0.05-0.1 parts of graphene, 0.5-2 parts of antioxidant, 0.2-2 parts of pigment and 1-5 parts of compatibilizer.

[0008] The melt flow rate of the polypropylene resin is 30-60g / 10min at 230°C and 2.16kg. If a high flow rate resin is used, the product strength will be low and cannot meet the use requirements; if a low flow rate resin is used, it will not be easy to fill the mold during molding.

[0009] The relative viscosity of the polyhexamethylene adipamide is 2.3-2.6.

[0010] The carbon fiber is composed of the following tow specifications according to weight percentage: 5-10% for tows less than 24K, 10-20% for 24K to 48K, and 65-80% for tows greater than 48K; the sum of the weight percentages of each tow specification is 100%. If the proportion of small tows is too large, they are easy to agglomerate together during product production and are difficult to disperse, resulting in poor product appearance and poor formability, and the smaller the tow, the more expensive it is; if the proportion of small tows is too small, the strength of the molded product is low, so the present invention requires the use of carbon fibers of different tow specifications.

[0011] The graphene is single-layer graphene.

[0012] The antioxidant is any one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine and tris(2,4-di-tert-butylphenyl)phosphite.

[0013] The pigment is a masterbatch.

[0014] The compatibilizer is maleic anhydride grafted polypropylene.

[0015] The present invention also provides a method for preparing the lightweight automobile bumper, which comprises the following steps:

[0016] S1. Mix the raw materials except carbon fiber according to the formula amount and add them into a twin-screw extruder;

[0017] S2, the traction device transports the carbon fiber to the die head and impregnates it, and mixes and plasticizes the carbon fiber and the raw material in step S1 evenly;

[0018] S3, the plasticized raw material is pulled and extruded, and then cooled, pelletized and dried to obtain pellets;

[0019] S4. Dry the pellets and then injection mold them into a bumper.

[0020] The extrusion temperature is 200°C to 260°C; the injection molding temperature is 210°C to 270°C.

[0021] The lightweight automobile bumper provided by the present invention uses polypropylene resin as the main raw material. Since the processing temperature of polypropylene is low, the polypropylene material is easily degraded when mixed with carbon fiber alone. The present invention significantly improves the processing performance of polypropylene resin and carbon fiber by adding polyhexamethylene adipamide with high processing temperature and excellent flow performance and graphene with lubricating effect. A lightweight automobile bumper with excellent strength is prepared by matching various raw materials.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The lightweight automobile bumper provided by the present invention has simple raw material composition, low cost and simple processing technology. The automobile bumper provided by the present invention has the characteristics of light weight and excellent performance, and its density is 1.0-1.2g / cm 3 The flexural modulus is 11.5~15.0GPa, the impact strength is 9.5~11.0kJ / ㎡, and the tensile strength is 83~105MPa. DETAILED DESCRIPTION

[0024] The present invention is described in detail below with reference to the embodiments.

[0025] Example 1

[0026] A lightweight automobile bumper is prepared from the raw materials and weight parts of the composition described in Example 1 in Table 1, wherein the melt flow rate of the polypropylene resin is 40 g / 10 min, the relative viscosity of polyhexamethylene adipamide is 2.35, the graphene is a single-layer graphene, the pigment is a masterbatch, the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, the compatibilizer is maleic anhydride grafted polypropylene, and the bundle composition of the carbon fiber and the weight percentage of each bundle are shown in Table 2.

[0027] The preparation method of the lightweight automobile bumper is as follows:

[0028] S1. Mix the raw materials except carbon fiber according to the formula amount and add them into a twin-screw extruder;

[0029] S2, the traction device transports the carbon fiber to the die head and impregnates it, and mixes and plasticizes the carbon fiber and the raw material in step S1 evenly;

[0030] S3, the plasticized raw materials are extruded and granulated by a parallel twin-screw extruder at a processing temperature of 240°C, and then cooled, pelletized and dried to obtain granules;

[0031] S4, drying the granules, and then injection molding, the mold temperature is 50°C, the injection temperature is 250°C, and after injection molding, the mold is processed and opened to obtain a finished automobile bumper.

[0032] Table 1 Raw material composition and weight of lightweight automobile bumper

[0033]

[0034]

[0035] Table 2 Composition of carbon fiber harnesses and weight percentage of each harness

[0036] Carbon fiber with tow less than 24K Carbon fiber with tow 24K~48K Carbon fiber with tow greater than 48K Example 1 5 20 75 Example 2 10 20 70 Example 3 7 15 78 Example 4 10 17 73 Example 5 10 15 75 Example 6 8 17 75 Example 7 5 15 80 Comparative Example 1 / 25 75 Comparative Example 2 2 30 68 Comparative Example 3 / / 100 Comparative Example 4 5 5 90 Comparative Example 5 / 40 60 Comparative Example 6 2 25 73

[0037] Example 2

[0038] A lightweight automobile bumper is prepared from the raw materials and weight portions of the composition described in Example 2 in Table 1, wherein the melt flow rate of the polypropylene resin is 60 g / 10 min, the relative viscosity of polyhexamethylene adipamide is 2.6, the graphene is a single-layer graphene, the pigment is a masterbatch, the antioxidant is a compound of N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine and tris(2,4-di-tert-butylphenyl)phosphite in a weight ratio of 1:1, the compatibilizer is maleic anhydride grafted polypropylene, and the bundle composition of the carbon fiber and the weight percentage of each bundle are as shown in Table 2.

[0039] The preparation method of the lightweight automobile bumper is as follows:

[0040] S1. Mix the raw materials except carbon fiber according to the formula amount and add them into a twin-screw extruder;

[0041] S2, the traction device transports the carbon fiber to the die head and impregnates it, and mixes and plasticizes the carbon fiber and the raw material in step S1 evenly;

[0042] S3, the plasticized raw materials are extruded and granulated by a parallel twin-screw extruder at a processing temperature of 245°C, and then cooled, pelletized and dried to obtain granules;

[0043] S4, drying the granules, and then injection molding, the mold temperature is 50°C, the injection temperature is 255°C, and after injection molding, the mold is processed and opened to obtain a finished automobile bumper.

[0044] Example 3

[0045] A lightweight automobile bumper is prepared from the raw materials and weight portions of the composition described in Example 3 in Table 1, wherein the melt flow rate of the polypropylene resin is 50 g / 10 min, the relative viscosity of polyhexamethylene adipamide is 2.5, the graphene is a single-layer graphene, the pigment is a masterbatch, the antioxidant is N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, the compatibilizer is maleic anhydride grafted polypropylene, and the bundle composition of the carbon fiber and the weight percentage of each bundle are shown in Table 2.

[0046] The preparation method of the lightweight automobile bumper is as follows:

[0047] S1. Mix the raw materials except carbon fiber according to the formula amount and add them into a twin-screw extruder;

[0048] S2, the traction device transports the carbon fiber to the die head and impregnates it, and mixes and plasticizes the carbon fiber and the raw material in step S1 evenly;

[0049] S3, the plasticized raw materials are extruded and granulated by a parallel twin-screw extruder at a processing temperature of 250°C, and then cooled, pelletized and dried to obtain granules;

[0050] S4, drying the granules, and then injection molding, the mold temperature is 50°C, the injection temperature is 260°C, and after injection molding, the mold is processed and opened to obtain a finished automobile bumper.

[0051] Example 4

[0052] A lightweight automobile bumper is prepared from the raw materials and weight parts of the composition described in Example 4 in Table 1, wherein the melt flow rate of the polypropylene resin is 40 g / 10 min, the relative viscosity of polyhexamethylene adipamide is 2.4, the graphene is a single-layer graphene, the pigment is a masterbatch, the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, the compatibilizer is maleic anhydride grafted polypropylene, and the bundle composition of the carbon fiber and the weight percentage of each bundle are shown in Table 2.

[0053] The preparation method of the lightweight automobile bumper is as follows:

[0054] S1. Mix the raw materials except carbon fiber according to the formula amount and add them into a twin-screw extruder;

[0055] S2, the traction device transports the carbon fiber to the die head and impregnates it, and mixes and plasticizes the carbon fiber and the raw material in step S1 evenly;

[0056] S3, the plasticized raw materials are extruded and granulated by a parallel twin-screw extruder at a processing temperature of 255°C, and then cooled, pelletized and dried to obtain granules;

[0057] S4, drying the granules, and then injection molding, the mold temperature is 50°C, the injection temperature is 265°C, and after injection molding, the mold is processed and opened to obtain a finished automobile bumper.

[0058] Example 5

[0059] A lightweight automobile bumper is prepared from the raw materials and weight parts of the composition described in Example 5 in Table 1, wherein the melt fluid flow rate of the polypropylene resin is 40 g / 10 min, the relative viscosity of polyhexamethylene adipamide is 2.4, the graphene is a single-layer graphene, the pigment is a masterbatch, the antioxidant is a compound of N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine and tris(2,4-di-tert-butylphenyl)phosphite in a mass ratio of 1:1, the compatibilizer is maleic anhydride grafted polypropylene, and the bundle composition of the carbon fiber and the weight percentage of each bundle are shown in Table 2.

[0060] The preparation method of the lightweight automobile bumper is as follows:

[0061] S1. Mix the raw materials except carbon fiber according to the formula amount and add them into a twin-screw extruder;

[0062] S2, the traction device transports the carbon fiber to the die head and impregnates it, and mixes and plasticizes the carbon fiber and the raw material in step S1 evenly;

[0063] S3, the plasticized raw materials are extruded and granulated by a parallel twin-screw extruder at a processing temperature of 260°C, and then cooled, pelletized and dried to obtain granules;

[0064] S4, drying the granules, and then injection molding, the mold temperature is 50°C, the injection temperature is 270°C, and after injection molding, the mold is processed and opened to obtain a finished automobile bumper.

[0065] Example 6

[0066] A lightweight automobile bumper is prepared from the raw materials and weight portions of the composition described in Example 6 in Table 1, wherein the melt fluid flow rate of the polypropylene resin is 40 g / 10 min, the relative viscosity of polyhexamethylene adipamide is 2.35, the graphene is a single-layer graphene, the pigment is a masterbatch, the antioxidant is a compound of N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine and tris(2,4-di-tert-butylphenyl)phosphite in a mass ratio of 1:1, the compatibilizer is maleic anhydride grafted polypropylene, and the bundle composition of the carbon fiber and the weight percentage of each bundle are shown in Table 2.

[0067] The preparation method of the lightweight automobile bumper is as follows:

[0068] S1. Mix the raw materials except carbon fiber according to the formula amount and add them into a twin-screw extruder;

[0069] S2, the traction device transports the carbon fiber to the die head and impregnates it, and mixes and plasticizes the carbon fiber and the raw material in step S1 evenly;

[0070] S3, the plasticized raw materials are extruded and granulated by a parallel twin-screw extruder at a processing temperature of 260°C, and then cooled, pelletized and dried to obtain granules;

[0071] S4, drying the granules, and then injection molding, the mold temperature is 50°C, the injection temperature is 260°C, and after injection molding, the mold is processed and opened to obtain a finished automobile bumper.

[0072] Example 7

[0073] A lightweight automobile bumper is prepared from the raw materials and weight parts of the composition described in Example 7 in Table 1, wherein the melt flow rate of the polypropylene resin is 60 g / 10 min, the relative viscosity of polyhexamethylene adipamide is 2.6, the graphene is a single-layer graphene, the pigment is a masterbatch, the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, the compatibilizer is maleic anhydride grafted polypropylene, and the bundle composition of the carbon fiber and the weight percentage of each bundle are shown in Table 2.

[0074] The preparation method of the lightweight automobile bumper is as follows:

[0075] S1. Mix the raw materials except carbon fiber according to the formula amount and add them into a twin-screw extruder;

[0076] S2, the traction device transports the carbon fiber to the die head and impregnates it, and mixes and plasticizes the carbon fiber and the raw material in step S1 evenly;

[0077] S3, the plasticized raw materials are extruded and granulated by a parallel twin-screw extruder at a processing temperature of 250°C, and then cooled, pelletized and dried to obtain granules;

[0078] S4, drying the granules, and then injection molding, the mold temperature is 50°C, the injection temperature is 270°C, and after injection molding, the mold is processed and opened to obtain a finished automobile bumper.

[0079] Comparative Example 1

[0080] A car bumper is prepared from the raw materials and weight parts of the composition described in Comparative Example 1 in Table 1, wherein the melt flow rate of the polypropylene resin is 50 g / 10 min, the relative viscosity of polyhexamethylene adipamide is 2.5, the pigment is a masterbatch, the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, the compatibilizer is maleic anhydride grafted polypropylene, and the bundle composition of the carbon fiber and the weight percentage of each bundle are shown in Table 2.

[0081] The preparation method of the lightweight automobile bumper is as follows:

[0082] S1. Mix the raw materials except carbon fiber according to the formula amount and add them into a twin-screw extruder;

[0083] S2, the traction device transports the carbon fiber to the die head and impregnates it, and mixes and plasticizes the carbon fiber and the raw material in step S1 evenly;

[0084] S3, the plasticized raw materials are extruded and granulated by a parallel twin-screw extruder at a processing temperature of 240°C, and then cooled, pelletized and dried to obtain granules;

[0085] S4, drying the granules, and then injection molding, the mold temperature is 50°C, the injection temperature is 250°C, and after injection molding, the mold is processed and opened to obtain a finished automobile bumper.

[0086] Comparative Example 2

[0087] A car bumper is prepared from the raw materials and weight parts of the composition described in Comparative Example 2 in Table 1, wherein the melt flow rate of the polypropylene resin is 40 g / 10 min, the pigment is a masterbatch, the antioxidant is N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine, the compatibilizer is maleic anhydride grafted polypropylene, and the bundle composition of the carbon fiber and the weight percentage of each bundle are shown in Table 2.

[0088] The preparation method of the lightweight automobile bumper is as follows:

[0089] S1. Mix the raw materials except carbon fiber according to the formula amount and add them into a twin-screw extruder;

[0090] S2, the traction device transports the carbon fiber to the die head and impregnates it, and mixes and plasticizes the carbon fiber and the raw material in step S1 evenly;

[0091] S3, the plasticized raw materials are extruded and granulated by a parallel twin-screw extruder at a processing temperature of 250°C, and then cooled, pelletized and dried to obtain granules;

[0092] S4, drying the granules, and then injection molding, the mold temperature is 50°C, the injection temperature is 270°C, and after injection molding, the mold is processed and opened to obtain a finished automobile bumper.

[0093] Comparative Example 3

[0094] A car bumper is prepared from the raw materials and weight parts of the composition described in Comparative Example 3 in Table 1, wherein the melt flow rate of the polypropylene resin is 30 g / 10 min, the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, the compatibilizer is maleic anhydride grafted polypropylene, and the bundle composition of the carbon fiber and the weight percentage of each bundle are shown in Table 2.

[0095] The preparation method of the lightweight automobile bumper is as follows:

[0096] S1. Mix the raw materials except carbon fiber according to the formula amount and add them into a twin-screw extruder;

[0097] S2, the traction device transports the carbon fiber to the die head and impregnates it, and mixes and plasticizes the carbon fiber and the raw material in step S1 evenly;

[0098] S3, the plasticized raw materials are extruded and granulated by a parallel twin-screw extruder at a processing temperature of 260°C, and then cooled, pelletized and dried to obtain granules;

[0099] S4, drying the granules, and then injection molding, the mold temperature is 50°C, the injection temperature is 270°C, and after injection molding, the mold is processed and opened to obtain a finished automobile bumper.

[0100] Comparative Example 4

[0101] A car bumper is prepared from the raw materials and weight parts of the composition described in Comparative Example 4 in Table 1, wherein the melt fluid flow rate of the polypropylene resin is 50 g / 10 min, the pigment is a masterbatch, the antioxidant is a compound of N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine and tris(2,4-di-tert-butylphenyl)phosphite in a mass ratio of 1:1, the compatibilizer is maleic anhydride grafted polypropylene, and the bundle composition of the carbon fiber and the weight percentage of each bundle are shown in Table 2.

[0102] The preparation method of the lightweight automobile bumper is as follows:

[0103] S1. Mix the raw materials except carbon fiber according to the formula amount and add them into a twin-screw extruder;

[0104] S2, the traction device transports the carbon fiber to the die head and impregnates it, and mixes and plasticizes the carbon fiber and the raw material in step S1 evenly;

[0105] S3, the plasticized raw materials are extruded and granulated by a parallel twin-screw extruder at a processing temperature of 250°C, and then cooled, pelletized and dried to obtain granules;

[0106] S4, drying the granules, and then injection molding, the mold temperature is 50°C, the injection temperature is 260°C, and after injection molding, the mold is processed and opened to obtain a finished automobile bumper.

[0107] Comparative Example 5

[0108] A car bumper is prepared from the raw materials and weight parts of the composition described in Comparative Example 5 in Table 1, wherein the melt flow rate of the polypropylene resin is 30 g / 10 min, the relative viscosity of polyhexamethylene adipamide is 2.6, the graphene is a single-layer graphene, the pigment is a masterbatch, the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, the compatibilizer is maleic anhydride grafted polypropylene, and the bundle composition of the carbon fiber and the weight percentage of each bundle are shown in Table 2.

[0109] The preparation method of the lightweight automobile bumper is as follows:

[0110] S1. Mix the raw materials except carbon fiber according to the formula amount and add them into a twin-screw extruder;

[0111] S2, the traction device transports the carbon fiber to the die head and impregnates it, and mixes and plasticizes the carbon fiber and the raw material in step S1 evenly;

[0112] S3, the plasticized raw materials are extruded and granulated by a parallel twin-screw extruder at a processing temperature of 260°C, and then cooled, pelletized and dried to obtain granules;

[0113] S4, drying the granules, and then injection molding, the mold temperature is 50°C, the injection temperature is 270°C, and after injection molding, the mold is processed and opened to obtain a finished automobile bumper.

[0114] Comparative Example 6

[0115] A car bumper is prepared from the raw materials and weight parts of the composition described in Comparative Example 6 in Table 1, wherein the melt flow rate of the polypropylene resin is 30 g / 10 min, the relative viscosity of polyhexamethylene adipamide is 2.6, the graphene is a single-layer graphene, the pigment is a masterbatch, the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, the compatibilizer is maleic anhydride grafted polypropylene, and the bundle composition of the carbon fiber and the weight percentage of each bundle are shown in Table 2.

[0116] The preparation method of the lightweight automobile bumper is as follows:

[0117] S1. Mix the raw materials except carbon fiber according to the formula amount and add them into a twin-screw extruder;

[0118] S2, the traction device transports the carbon fiber to the die head and impregnates it, and mixes and plasticizes the carbon fiber and the raw material in step S1 evenly;

[0119] S3, the plasticized raw materials are extruded and granulated by a parallel twin-screw extruder at a processing temperature of 260°C, and then cooled, pelletized and dried to obtain granules;

[0120] S4, drying the granules, and then injection molding, the mold temperature is 50°C, the injection temperature is 270°C, and after injection molding, the mold is processed and opened to obtain a finished automobile bumper.

[0121] Test Case

[0122] The density is tested according to ISO-1183 standard, the sample size is 80*10*4mm, and the drainage method is used for testing.

[0123] The bending modulus is tested according to ISO-178 standard, the sample size is 80*10*4mm, the test rate is 2mm / min, and the span is 64mm.

[0124] The tensile strength was tested according to ISO-527 standard, the specimen was type 1A, the test rate was 5 mm / min, and the distance between the specimens was 115 mm.

[0125] Impact strength The impact strength test was carried out according to ISO-179 / 1eA, using a 5J pendulum, a span of 62mm, an impact speed of 2.9m / s, a spline size of 80*10*4mm, and a notch depth of 2mm.

[0126] The spiral flow length test conditions were as follows: the injection molding machine was set at 230°C, the injection molding mode was pressure controlled, the injection pressure was 98 MPa, and the sample thickness was 1 mm.

[0127] The above test results are shown in Table 3.

[0128] Table 3 Material performance test results

[0129]

[0130] It can be seen from Table 3 that Comparative Examples 1 to 6 are not prepared according to the formulation of the lightweight automobile bumper required by the present invention, resulting in the bending modulus, impact strength and tensile strength of the automobile bumper being inferior to those of the embodiments.

[0131] The detailed description of a lightweight automobile bumper and a method for preparing the same with reference to the above-mentioned embodiments is illustrative rather than restrictive, and several embodiments may be listed according to the limited scope. Therefore, changes and modifications without departing from the overall concept of the present invention should fall within the scope of protection of the present invention.

Claims

1. A lightweight automobile bumper, characterized in that: The invention is prepared from the following raw materials and parts by weight: 45-70 parts of polypropylene resin, 5-20 parts of polyhexamethylene adipamide, 25-40 parts of carbon fiber, 0.05-0.1 parts of graphene, 0.5-2 parts of antioxidant, 0.2-2 parts of pigment and 1-5 parts of compatibilizer.

2. The lightweight automobile bumper according to claim 1, characterized in that: The polypropylene resin has a melt flow rate of 30-60 g / 10 min at 230° C. and 2.16 kg.

3. The lightweight automobile bumper according to claim 1, characterized in that: The relative viscosity of the polyhexamethylene adipamide is 2.3-2.

6.

4. The lightweight automobile bumper according to claim 1, characterized in that: The carbon fiber is composed of the following tow specifications according to weight percentage: 5-10% of tows less than 24K, 10-20% of 24K to 48K, and 65-80% of tows greater than 48K; the total weight percentage of each tow specification is 100%.

5. The lightweight automobile bumper according to claim 1, characterized in that: The graphene is single-layer graphene.

6. The lightweight automobile bumper according to claim 1, characterized in that: The antioxidant is any one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine and tris(2,4-di-tert-butylphenyl)phosphite.

7. The lightweight automobile bumper according to claim 1, characterized in that: The pigment is a masterbatch.

8. The lightweight automobile bumper according to claim 1, characterized in that: The compatibilizer is maleic anhydride grafted polypropylene.

9. The method for preparing a lightweight automobile bumper according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: S1. Mix the raw materials except carbon fiber according to the formula amount and add them into a twin-screw extruder; S2, the traction device transports the carbon fiber to the die head and impregnates it, and mixes and plasticizes the carbon fiber and the raw material in step S1 evenly; S3, the plasticized raw material is pulled and extruded, and then cooled, pelletized and dried to obtain pellets; S4. Dry the pellets and then injection mold them into a bumper.

10. The preparation method according to claim 9, characterized in that: The extrusion temperature is 200°C to 260°C; The injection molding temperature is 210-270°C.

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