A glass fiber reinforced polypropylene material, its preparation method and application

Abstract

This invention discloses a glass fiber reinforced polypropylene material, its preparation method, and its application. The glass fiber reinforced polypropylene material comprises the following components in parts by weight: 55-95 parts polypropylene resin, 10-35 parts glass fiber, and 1-5 parts compatibilizer; wherein the polypropylene resin contains block copolymer polypropylene A and block copolymer polypropylene B in a weight ratio of (2-4):1; the average molecular weight M of block copolymer polypropylene A is... w The mass fraction of the copolymerized ethylene propylene diene monomer (EPDM) phase is 10%-20%, with a molecular weight of 200,000-290,000; the average molecular weight M of the block copolymerized polypropylene B is... w The mass fraction of the copolymerized ethylene propylene diene monomer (EPDM) phase is 11%-17% with a molecular weight ≥340,000. This invention produces glass fiber reinforced polypropylene materials by selecting block copolymers A and B with specific average molecular weights and EPDM phase contents. These materials exhibit strong tensile properties, flexural properties, and unnotched impact resistance under low-temperature conditions.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and more specifically, to a glass fiber reinforced polypropylene material, its preparation method, and its application. Background Technology

[0002] Polypropylene (PP) materials are widely used, especially in the automotive and home appliance industries, due to their advantages such as low density, excellent heat and chemical resistance, ease of processing and molding, high cost-effectiveness, and easy recyclability. To meet different application scenarios and further improve the performance of PP materials, technicians often modify them. For example, in various automotive parts, only a small number are processed using pure PP without any additives, while most parts are processed using modified PP with enhanced performance. In low-temperature working environments during winter, the performance of automotive parts made of PP materials changes, such as becoming brittle and easily damaged. This affects the vehicle's performance and poses a significant safety hazard for low-temperature driving. Improving the tensile, flexural, and unnotched impact properties of PP materials under low-temperature conditions can significantly reduce the probability of automotive parts becoming brittle and damaged in winter, mitigating the impact of low temperatures on vehicle use.

[0003] Therefore, developing a glass fiber reinforced polypropylene material with strong tensile, flexural, and unnotched impact properties under low-temperature conditions is of significant economic value. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a glass fiber reinforced polypropylene material, its preparation method and application. This glass fiber reinforced polypropylene material improves its tensile properties, flexural properties and unnotched impact properties under low temperature conditions by selecting two specific types of block copolymer polypropylene and controlling the ratio of the two specific types of block copolymer polypropylene.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides a glass fiber reinforced polypropylene material, comprising the following components in parts by weight:

[0007] 55-95 parts polypropylene resin, 10-35 parts glass fiber, and 1-5 parts compatibilizer;

[0008] in:

[0009] The polypropylene resin contains block copolymer polypropylene A and block copolymer polypropylene B in a weight ratio of (2-4):1;

[0010] The average molecular weight M of the block copolymer polypropylene Aw The mass fraction of the copolymer EPR phase (ethylene propylene diene monomer rubber phase) is 10%-20%, with a content of 200,000-290,000.

[0011] The average molecular weight M of the block copolymer polypropylene B w ≥340,000, with a mass fraction of 11%-17% for the copolymer EPR phase (ethylene propylene diene monomer rubber phase).

[0012] This invention selects molecules with a specific average molecular weight M. w Block copolymer polypropylene A and B with EPR (ethylene propylene diene monomer) content are used as the matrix polypropylene resin in glass fiber reinforced polypropylene materials. On the one hand, this disrupts the regular and compact arrangement of molecular chains in the crystalline regions, making the polypropylene resin more susceptible to deformation and energy absorption, reducing its rigidity, and enhancing its toughness. This allows the polypropylene resin to maintain a balance between rigidity and toughness even at low temperatures, which is beneficial for improving the tensile, flexural, and unnotched impact properties of glass fiber reinforced polypropylene materials at low temperatures. On the other hand, when block copolymer polypropylene A and B with specific average molecular weights are used in combination, due to the molecular... Different sizes and chain lengths make it easier for polypropylene resin to entangle and form a stable, tough network structure. This network structure can also bridge glass fibers, strengthen their connection, and improve the strength of the network structure. This allows polypropylene resin to maintain a balance between rigidity and toughness even at low temperatures, which is beneficial for improving the tensile, flexural, and unnotched impact properties of glass fiber reinforced polypropylene materials at low temperatures. Furthermore, the network structure formed by the entanglement of block copolymer polypropylene A and B with different average molecular weights, after being bridged with glass fibers, can improve the melt strength of glass fiber reinforced polypropylene materials, which is beneficial for improving the foaming rate of glass fiber reinforced polypropylene materials.

[0013] Preferably, the polypropylene resin accounts for ≥60.0% of the weight of the glass fiber reinforced polypropylene material.

[0014] More preferably, the polypropylene resin accounts for ≥65.0% of the weight of the glass fiber reinforced polypropylene material.

[0015] In this invention, the average molecular weight of block copolymer polypropylene A and / or B is determined by gel permeation chromatography (GPC, volume exclusion chromatography) according to GB / T36214.4-2018 standard. w .

[0016] In this invention, the method for testing the copolymer EPR phase content of the block copolymer polypropylene A and / or B is as follows:

[0017] Add M1g of block copolymer polypropylene A or block copolymer polypropylene B to xylene, heat under reflux at 135-140℃ for 50-100min, cool to crystallize, filter, take the filtrate, evaporate and dry, and record the mass of the dried substance as M2. Then, the content of the copolymer EPR phase (diethylene propylene diene monomer rubber phase) of block copolymer polypropylene A or block copolymer polypropylene B = M2 / M1×100%.

[0018] Preferably, the weight ratio of the block copolymer polypropylene A and the block copolymer polypropylene B is one or any two of the following: 2:1, 2.3:1, 2.5:1, 2.6:1, 2.9:1, 3:1, 3.3:1, 3.5:1, 3.6:1, 3.9:1, 4:1.

[0019] Preferably, the average molecular weight M of the block copolymer polypropylene A is... w The mass fraction of the copolymer EPR phase content of the block copolymer polypropylene A is one or any two of the following values: 200,000, 205,000, 206,000, 210,000, 215,000, 220,000, 225,000, 230,000, 235,000, 240,000, 245,000, 250,000, 255,000, 260,000, 265,000, 270,000, 275,000, 280,000, 282,000, 285,000, and 290,000;

[0020] More preferably, the average molecular weight M of the block copolymer polypropylene A is... w The range is 205,000 to 285,000.

[0021] More preferably, the mass fraction of the copolymer EPR phase (ethylene propylene diene monomer rubber phase) in the block copolymer polypropylene A is 10.3%-19.7%.

[0022] Preferably, the average molecular weight M of the block copolymer polypropylene B is... w The value is within the range of one or any two of the following: 340,000, 342,000, 350,000, 360,000, 380,000, 385,000, 387,000, 400,000, 420,000, 440,000, 460,000, 480,000, 500,000, 520,000, 540,000, 550,000, 555,000, 560,000, 580,000, and 600,000; the mass fraction of the copolymer EPR phase content of the block copolymer polypropylene B is within the range of one or any two of the following: 11%, 11.9%, 12%, 13%, 14%, 15%, 15.8%, 16%, 16.6%, and 17%.

[0023] More preferably, the average molecular weight M of the block copolymer polypropylene B is... wThe range is 340,000 to 600,000.

[0024] More preferably, the average molecular weight M of the block copolymer polypropylene B is... w The range is 380,000 to 560,000.

[0025] More preferably, the mass fraction of the copolymer EPR phase (ethylene propylene diene monomer rubber phase) content in the block copolymer polypropylene B is 11.9%-16.6%.

[0026] Preferably, the glass fiber has an average length of 0.40-1.00 mm and an average diameter of 10-15 μm.

[0027] More preferably, the average length of the glass fiber is 0.60-0.90 mm.

[0028] In the glass fiber reinforced polypropylene material of this invention, the glass fibers are connected to each other through a network structure formed by the entanglement of block copolymer polypropylene A and B with different average molecular weights. This allows the polypropylene resin to maintain a state of rigidity-toughness balance even at low temperatures, while simultaneously improving the melt strength of the glass fiber reinforced polypropylene material. This, in turn, enhances the tensile properties, flexural properties, and unnotched impact properties of the glass fiber reinforced polypropylene material at low temperatures, as well as increasing its foaming rate. The effectiveness of the glass fibers depends on their average length and dispersion within the polypropylene resin.

[0029] This invention improves the dispersion of glass fibers in polypropylene resin by adjusting the average length of the glass fibers. This allows for easier stress transfer to the glass fibers, leading to better tensile, flexural, and unnotched impact properties of glass fiber reinforced polypropylene (GFRP) materials at low temperatures, and also improving the foaming rate. Conversely, when the average length of the glass fibers is too short, stress is difficult to transfer, hindering the improvement of tensile, flexural, and unnotched impact properties at low temperatures, and the foaming rate. Conversely, when the average length of the glass fibers is too long, uniform dispersion in the polypropylene resin is difficult, resulting in fewer localized glass fibers, creating weak points that are more prone to cracking and breakage. This, in turn, hinders the improvement of tensile, flexural, and unnotched impact properties at low temperatures and the improvement of the foaming rate.

[0030] More preferably, the average length of the glass fiber is 0.40mm, 0.42mm, 0.45mm, 0.46mm, 0.48mm, 0.49mm, 0.50mm, 0.52mm, 0.54mm, 0.55mm, 0.56mm, 0.58mm, 0.60mm, 0.62mm, 0.64mm, 0.65mm, 0.66mm, 0.68mm, 0.70mm, 0.71mm, 0.72mm, 0.73mm, 0.74mm, or 0.75mm. The diameter of the glass fiber is within the range of one or any two of the following: 0.76mm, 0.78mm, 0.80mm, 0.82mm, 0.84mm, 0.85mm, 0.86mm, 0.87mm, 0.88mm, 0.90mm, 0.92mm, 0.94mm, 0.95mm, 0.96mm, 0.97mm, 0.98mm, and 1.00mm; the diameter of the glass fiber is within the range of one or any two of the following: 10μm, 11μm, 12μm, 13μm, 14μm, and 15μm.

[0031] More preferably, the average length of the glass fiber is 0.65-0.87 mm, specifically 0.65-0.87 mm.

[0032] In this invention, the method for measuring the average length of glass fibers in glass fiber reinforced polypropylene material is as follows: the glass fiber reinforced polypropylene material is calcined at 625℃±25℃ for 30-90 minutes, cooled, and 150-500 glass fibers are taken from it. The length of the glass fibers is measured and their arithmetic mean is calculated as the average length of glass fibers in glass fiber reinforced polypropylene material.

[0033] Preferably, in the components of the glass fiber reinforced polypropylene material, the weight parts of polypropylene resin are 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, and 95 parts, or any two of these values; the weight parts of glass fiber are 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, and 35 parts, or any two of these values; and the weight parts of compatibilizer are 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, and 5 parts, or any two of these values.

[0034] Preferably, the glass fiber reinforced polypropylene material comprises the following components in parts by weight:

[0035] 60-90 parts polypropylene resin, 10-30 parts glass fiber, and 1-3 parts compatibilizer.

[0036] Preferably, the compatibilizer is at least one of maleic anhydride-grafted polypropylene (PP-g-MAH) and maleic anhydride-grafted POE (POE-g-MAH).

[0037] Preferably, the glass fiber reinforced polypropylene material further includes an antioxidant.

[0038] More preferably, the antioxidant is present in 0.1-2 parts by weight.

[0039] More preferably, the antioxidant is at least one of hindered phenolic antioxidants and phosphite antioxidants.

[0040] In this invention, commonly used hindered phenolic antioxidants in the art can be used, such as pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010, CAS No.: 6683-19-8), 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione (antioxidant TH-1790, CAS No.: 40601-76-1), etc.

[0041] In this invention, commonly used phosphite antioxidants in the art can be used, such as tris(2,4-di-tert-butyl)phosphite (antioxidant 168, CAS No.: 31570-04-4), etc.

[0042] Those skilled in the art can reasonably select the average length of the glass fiber raw material. Generally speaking, the average length of the glass fiber raw material is greater than the average length of the glass fiber in the glass fiber reinforced polypropylene material.

[0043] Preferably, the glass fiber raw material has an average length of 1-6 mm and an average diameter of 10-15 μm.

[0044] More preferably, the glass fiber raw material has an average length of 2-4.5 mm and an average diameter of 13 μm.

[0045] Secondly, the present invention provides a method for preparing glass fiber reinforced polypropylene material, comprising the following steps:

[0046] S1. Take the raw materials of the glass fiber reinforced polypropylene material other than the glass fiber raw material, mix them to obtain a premix;

[0047] S2. Glass fiber raw material is added during the melt extrusion of the premix to obtain glass fiber reinforced polypropylene material.

[0048] In this invention, those skilled in the art can adjust the average length of the glass fiber raw material to the required average length of the glass fiber in the glass fiber reinforced polypropylene material using the above-described preparation method.

[0049] Preferably, in step S1, the mixing speed is 400-800 rpm and the time is 1-3 min.

[0050] Preferably, in step S2, the conditions for melt extrusion are:

[0051] The temperatures in zones 1, 2, 3, 4, 5, 6, 7, 8, and 9 are 80-220℃ respectively. The length-to-diameter ratio of the screw extruder is (40-48):1.

[0052] More preferably, the length-to-diameter ratio of the screw extruder is 40:1.

[0053] In this invention, the screw extruder is a twin-screw extruder commonly used in the art.

[0054] Thirdly, the present invention provides an application of glass fiber reinforced polypropylene material in automobiles.

[0055] In this invention, the glass fiber reinforced polypropylene material can be used to manufacture various brackets in automobiles, such as front-end frames, sunroof frames, and dashboard frames.

[0056] When the glass fiber reinforced polypropylene material of the present invention is used to prepare the instrument panel frame, it has high unnotched impact strength at low temperature and a balance of rigidity and toughness inside the material. This allows the instrument panel frame to open along the weakening line during airbag explosion without causing fragmentation.

[0057] Fourthly, the present invention provides a foamed polypropylene material, which is obtained by foaming and molding the glass fiber reinforced polypropylene material described in the first aspect.

[0058] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0059] This invention selects molecules with a specific average molecular weight M. wBlock copolymer polypropylene A and B with EPR (ethylene propylene diene monomer) content are used as the matrix polypropylene resin in glass fiber reinforced polypropylene materials. On the one hand, this disrupts the regular and compact arrangement of molecular chains in the crystalline regions, making the polypropylene resin more susceptible to deformation and energy absorption, reducing its rigidity, and enhancing its toughness. This allows the polypropylene resin to maintain a balance between rigidity and toughness even at low temperatures, which is beneficial for improving the tensile, flexural, and unnotched impact properties of glass fiber reinforced polypropylene materials at low temperatures. On the other hand, when block copolymer polypropylene A and B with specific average molecular weights are used in combination, due to the molecular... Different sizes and chain lengths make it easier for polypropylene resin to entangle and form a stable, tough network structure. This network structure can also bridge glass fibers, strengthen their connection, and improve the strength of the network structure. This allows polypropylene resin to maintain a balance between rigidity and toughness even at low temperatures, which is beneficial for improving the tensile, flexural, and unnotched impact properties of glass fiber reinforced polypropylene materials at low temperatures. Furthermore, the network structure formed by the entanglement of block copolymer polypropylene A and B with different average molecular weights, after being bridged with glass fibers, can improve the melt strength of glass fiber reinforced polypropylene materials, which is beneficial for improving the foaming rate of glass fiber reinforced polypropylene materials. Detailed Implementation

[0060] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0061] The reagents used in the various embodiments and comparative examples of this invention are as follows:

[0062] Block copolymer polypropylene A-1, PP EP548R, CNOOC Shell, average molecular weight M w The value is 264969, and the mass fraction of the copolymer EPR phase content is 16.9%.

[0063] Block copolymer polypropylene A-2, PP K7227, Sinopec Guangzhou, average molecular weight M w The value is 206488, and the mass fraction of the copolymer EPR phase content is 10.3%.

[0064] Block copolymer polypropylene A-3, PP 7033N, ExxonMobil, average molecular weight M w The value is 281963, and the mass fraction of the copolymer EPR phase content is 19.7%.

[0065] Block copolymer polypropylene A-4, PP BX3920, SK Korea, average molecular weight M w The value is 161495, and the mass fraction of the copolymer EPR phase content is 8.7%.

[0066] Block copolymer polypropylene A-5, PP SP179, Lanzhou Petrochemical, average molecular weight M w The value is 280024, and the mass fraction of the copolymer EPR phase content is 24.5%.

[0067] Block copolymer polypropylene B-1, PP 3010, Formosa Plastics (Taiwan Plastics Industrial Co., Ltd.), average molecular weight M w The value is 387474, and the mass fraction of the copolymer EPR phase content is 11.9%.

[0068] Block copolymer polypropylene B-2, PP B8101, Yanshan Petrochemical, average molecular weight M w The value is 552125, and the mass fraction of the copolymer EPR phase content is 15.8%.

[0069] Block copolymer polypropylene B-3, PP K8003, Taiwan Chemical Fiber Co., Ltd., average molecular weight M w The value is 341408, and the mass fraction of the copolymer EPR phase content is 16.6%.

[0070] Block copolymer polypropylene B-4, PP 7032E3, ExxonMobil, average molecular weight M w The value is 332845, and the mass fraction of the copolymer EPR phase content is 16.5%.

[0071] Glass fiber raw material-1, ECS13-04-508A, China Jushi Co., Ltd., glass fiber with an average length of 4mm and an average diameter of 13μm;

[0072] Glass fiber raw material-2, ECS13-03-508A, China Jushi Co., Ltd., glass fiber with an average length of 3mm and an average diameter of 13μm;

[0073] Glass fiber raw material-3, ECS13-4.5-T538D, Taishan Glass Fiber Co., Ltd., glass fiber with an average length of 4.5mm and an average diameter of 13μm;

[0074] Glass fiber raw material-4, glass fibers with an average length of 2 mm and an average diameter of 13 μm, are obtained by cutting and shredding glass fiber raw material-1 (ECS13-04-508A, China Jushi Co., Ltd.);

[0075] Glass fiber raw material-5, ECS13-06-558, China Jushi Co., Ltd., glass fiber with an average length of 6mm and an average diameter of 13μm;

[0076] Maleic anhydride-grafted polypropylene (PP-g-MAH), commercially available;

[0077] Pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Antioxidant 1010), commercially available;

[0078] Tris(2,4-di-tert-butyl) phenyl phosphite (antioxidant 168), commercially available;

[0079] In the various embodiments and comparative examples of this invention:

[0080] (1) Test method for the average molecular weight of block copolymer polypropylene A and / or B: The average molecular weight M of block copolymer polypropylene A or B shall be measured by gel permeation chromatography (GPC, volume exclusion chromatography) according to GB / T36214.4-2018 standard. w ;

[0081] (2) Test method for the content of EPR phase in block copolymer polypropylene A and / or B: Add 2g of block copolymer polypropylene A or block copolymer polypropylene B to 200mL xylene, heat and reflux at 135-140℃ for 60min, cool and crystallize at 25℃, filter, take the filtrate, rotary evaporate, and dry to constant weight. The mass of the substance after drying to constant weight is recorded as M2. Then the content of EPR phase (diethylene propylene rubber phase) in block copolymer polypropylene A or block copolymer polypropylene B = M2 / 2g×100%.

[0082] (3) The method for measuring the average length of glass fibers in glass fiber reinforced polypropylene material is as follows: Place the glass fiber reinforced polypropylene material in a crucible and calcine it in a muffle furnace at 625℃±25℃ for 60 minutes. Take it out and cool it. Place the calcined solid in an evaporating dish (a small amount of water can be added to the evaporating dish to help disperse the glass fibers after gentle stirring). Take 300 glass fibers from it, measure the length of the glass fibers with a two-dimensional microscope and calculate its arithmetic mean, which is taken as the average length of glass fibers in glass fiber reinforced polypropylene material.

[0083] Examples 1-18 and Comparative Examples 1-10

[0084] Examples 1-18 and Comparative Examples 1-10 provide different glass fiber reinforced polypropylene materials, which differ only in the type and amount of each component. By weight, Examples 1-18 and Comparative Examples 1-10 include the components shown in Table 1.

[0085] The preparation method of the above-mentioned glass fiber reinforced polypropylene material includes the following steps:

[0086] S1. Take the raw materials of the glass fiber reinforced polypropylene material other than the glass fiber raw material, and mix them with a high-speed mixer at 600 rpm for 2 minutes to obtain a premix;

[0087] S2. When the premixed material is placed in the main feed port of the twin-screw extruder for melt extrusion, glass fiber raw material is added through the side feed port of the twin-screw extruder to obtain glass fiber reinforced polypropylene material;

[0088] In step S2, the conditions for melt extrusion are as follows:

[0089] The temperature in zone 1 is 90℃, zone 2 is 180℃, zone 3 is 200℃, zone 4 is 200℃, zone 5 is 200℃, zone 6 is 200℃, zone 7 is 200℃, zone 8 is 200℃, and zone 9 is 200℃. The main machine speed is 450 r / min; the length-to-diameter ratio of the twin-screw extruder is 40:1.

[0090] In addition, the average diameter of the glass fiber remains basically unchanged before and after the above preparation method is implemented, that is, the average diameter of the glass fiber raw material is basically the same as the average diameter of the glass fiber.

[0091] Table 1. Weight parts of each component in glass fiber reinforced polypropylene materials of Examples 1-18 and Comparative Examples 1-10

[0092]

[0093]

[0094]

[0095]

[0096] Performance testing

[0097] The following performance tests were performed on the glass fiber reinforced polypropylene materials of each embodiment and comparative example:

[0098] (1) Tensile property test at low temperature

[0099] Low-temperature tensile properties were tested according to ISO 527-2012, using 1A specimens, at a temperature of -30℃ and a tensile rate of 10 mm / min.

[0100] (2) Bending performance test at low temperature

[0101] Low-temperature bending performance was performed according to ISO178-2010, using an 80×10×4mm injection molded specimen, at a test temperature of -30℃, a bending rate of 2mm / min, and a span of 64mm.

[0102] (3) Low-temperature unnotched impact performance test

[0103] The impact performance of simply supported beams at low temperatures without notches was performed in accordance with ISO179-1993, using 80×10×4mm injection molded specimens, with a test temperature of -30℃ and a span of 62mm.

[0104] (4) Foaming effect test

[0105] S1. Preparation of non-foaming sample

[0106] A BS800-III 80-ton injection molding machine from Bocheng was used to injection mold glass fiber reinforced polypropylene material. A 10×10×3mm sample was cut out as a non-foaming sample. The injection molding process was as follows: injection temperature 200℃, injection speed 45g / s, injection pressure 45MPa, holding pressure 50MPa, holding time 15s, and cooling time 15s.

[0107] S2. Preparation of foamed sample

[0108] A BS800-III 80-ton injection molding machine from Bocheng was used. Foaming agent (EE25C, from Eiwa Fine Chemicals, Japan) was added to the glass fiber reinforced polypropylene material at a mass ratio of 100:1, and the mixture was then injected. A 10×10×3mm sample was cut and used as the foaming sample. The injection molding process was as follows: injection temperature 200℃, injection speed 75g / s, injection pressure 75MPa, holding time 30s, and cooling time 30s.

[0109] S3. Calculation of weight loss percentage

[0110] Weigh the non-foamed sample (m1) and the foamed sample (m2). The weight loss percentage (%) = (m1-m2) / m1×100%. The size of the weight loss percentage is used to characterize the foaming effect of the glass fiber reinforced polypropylene material. A larger weight loss percentage indicates a better foaming effect of the glass fiber reinforced polypropylene material.

[0111] The experimental results are shown in the table below:

[0112] Table 2 Performance test results of each embodiment and comparative example

[0113]

[0114]

[0115] As shown in Table 2, the glass fiber reinforced polypropylene material of the present invention exhibits strong tensile properties, flexural properties, and unnotched impact properties under low-temperature conditions. Furthermore, its tensile strength can reach over 93 MPa, its flexural strength over 145 MPa, and its unnotched impact strength can reach 38 kJ / m. 2 The weight loss before and after foaming can reach over 5.0%; specifically:

[0116] (1) By comparing Examples 1-7 and Comparative Examples 1-7, it can be seen that the present invention selects block copolymer polypropylene A and B with specific average molecular weights and EPR phase (ethylene propylene diene monomer rubber phase) content as the matrix polypropylene resin of glass fiber reinforced polypropylene material. On the one hand, it can disrupt the regularity and compactness of the molecular chain arrangement in the crystalline region, making the polypropylene resin easier to deform and absorb energy, reducing the rigidity of the polypropylene resin, enhancing the toughness of the polypropylene resin, and enabling the polypropylene resin to be in a state of rigidity-toughness balance even at low temperature conditions, which is beneficial to improving the tensile properties, flexural properties and unnotched impact properties of glass fiber reinforced polypropylene material at low temperature conditions; on the other hand, the block copolymers with specific average molecular weights... When copolymer polypropylene A and B are used together, they are more likely to entangle due to differences in molecular size and chain length, forming a stable and highly resilient network structure. This network also bridges the glass fibers, strengthening their connection and increasing the strength of the network structure. This allows the polypropylene resin to maintain a balance between rigidity and toughness even at low temperatures, which is beneficial for improving the tensile, flexural, and unnotched impact properties of glass fiber reinforced polypropylene materials at low temperatures. Furthermore, the network structure formed by the entanglement of different high-average-molecular-weight block copolymer polypropylene A and B, after bridging with glass fibers, can enhance the melt strength of glass fiber reinforced polypropylene materials, thus improving their foaming rate.

[0117] (2) By comparing Examples 1 and 8-11, it can be seen that in the glass fiber reinforced polypropylene material of the present invention, the glass fibers are connected to each other through a network structure formed by the entanglement of block copolymer polypropylene A and B with different average molecular weights. This allows the polypropylene resin to maintain a state of rigidity-toughness balance even at low temperatures, while also improving the melt strength of the glass fiber reinforced polypropylene material. Consequently, it improves the tensile properties, flexural properties, and unnotched impact properties of the glass fiber reinforced polypropylene material at low temperatures, as well as increasing the foaming rate of the glass fiber reinforced polypropylene material. When the average length of the glass fibers is preferably 0.60-0.90 mm, the glass fibers have better dispersibility in the polypropylene resin, and the stress in the system is more easily transferred to the glass fibers, which is more conducive to improving the tensile properties, flexural properties, and unnotched impact properties of the glass fiber reinforced polypropylene material at low temperatures, and also more conducive to increasing the foaming rate of the glass fiber reinforced polypropylene material.

[0118] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A glass fiber reinforced polypropylene material, characterized in that, The components include the following parts by weight: 55-95 parts polypropylene resin, 10-35 parts glass fiber, and 1-5 parts compatibilizer; in: The polypropylene resin contains block copolymer polypropylene A and block copolymer polypropylene B in a weight ratio of (2-4):1; The average molecular weight M of the block copolymer polypropylene A w The mass fraction of the copolymer binary ethylene propylene rubber phase is 10%-20%, with a value of 200,000-290,000. The average molecular weight M of the block copolymer polypropylene B w ≥340,000, with a mass fraction of 11%-17% for the copolymer binary ethylene propylene rubber phase; The test method for the content of the copolymeric ethylene propylene rubber phase in the block copolymer polypropylene A and / or B is as follows: Add 2g of block copolymer polypropylene A or block copolymer polypropylene B to 200mL of xylene, heat and reflux at 135-140℃ for 60min, cool and crystallize at 25℃, filter, take the filtrate, rotary evaporate, and dry to constant weight. The mass of the substance after drying to constant weight is recorded as M2. Then, the content of the copolymeric ethylene propylene rubber phase in the block copolymer polypropylene A or block copolymer polypropylene B = M2 / 2g × 100%.

2. The glass fiber reinforced polypropylene material as described in claim 1, characterized in that, Includes at least one of the following (1)-(2): (1) The average molecular weight M of the block copolymer polypropylene B w The range is 340,000 to 600,000. (2) The average length of the glass fiber is 0.40-1.00 mm and the average diameter is 10-15 μm.

3. The glass fiber reinforced polypropylene material as described in claim 2, characterized in that, Includes at least one of the following (1)-(2): (1) The average molecular weight Mw of the block copolymer polypropylene B is 380,000 to 560,000; (2) The average length of the glass fiber is 0.60-0.90 mm.

4. The glass fiber reinforced polypropylene material as described in claim 1, characterized in that, Includes at least one of the following (1)-(3): (1) The average molecular weight M of the block copolymer polypropylene A w The range is 205,000 to 285,000; (2) The mass fraction of the copolymer binary ethylene propylene rubber phase in the block copolymer polypropylene A is 10.3%-19.7%; (3) The mass fraction of the copolymer binary ethylene propylene rubber phase content of the block copolymer polypropylene B is 11.9%-16.6%.

5. The glass fiber reinforced polypropylene material as described in claim 1, characterized in that, The compatibilizer is at least one of maleic anhydride-grafted polypropylene and maleic anhydride-grafted POE.

6. The glass fiber reinforced polypropylene material as described in claim 1, characterized in that, The glass fiber reinforced polypropylene material also includes antioxidants.

7. The glass fiber reinforced polypropylene material as described in claim 1, characterized in that, The glass fiber reinforced polypropylene material comprises the following components in parts by weight: 60-90 parts polypropylene resin, 10-30 parts glass fiber, and 1-3 parts compatibilizer.

8. A method for preparing the glass fiber reinforced polypropylene material according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Take the raw materials of the glass fiber reinforced polypropylene material other than the glass fiber raw material, mix them to obtain a premix; S2. Glass fiber raw material is added during the melt extrusion of the premix to obtain glass fiber reinforced polypropylene material.

9. The use of the glass fiber reinforced polypropylene material according to any one of claims 1-7 in automobiles.

10. A foamed polypropylene material, characterized in that, It is prepared by foaming and molding the glass fiber reinforced polypropylene material according to any one of claims 1-7.

Images