Polypropylene composite material, and preparation method therefor and use thereof

Abstract

A polypropylene composite material, and a preparation method therefor and a use thereof, relating to the field of automotive interior and exterior materials. The polypropylene composite material comprises the following components in parts by weight: 59-90 parts of a polypropylene resin, 5-15 parts of a high-density polyethylene resin, 5-10 parts of a 1-octene-ethylene block copolymer, 5-10 parts of an ethylene-propylene copolymer, 5-15 parts of glass fiber, and 0.05-2 parts of a nucleating agent. The compounding of the 1-octene-ethylene block copolymer and the ethylene-propylene copolymer can improve the bending and cracking resistance of a glass fiber reinforced polypropylene composite resin; additionally, the addition of the high-density polyethylene resin can uniformly disperse the glass fiber in the polypropylene resin, making the polypropylene composite material have a good appearance.

Description

A polypropylene composite material and its preparation method and application Technical Field

[0001] The present invention belongs to the field of vehicle interior and exterior decoration materials, and particularly relates to a polypropylene composite material and a preparation method and application thereof. Background Art

[0002] Polypropylene, with its light density, widespread availability, low price, and lower carbon emissions than other materials, is widely used in automotive interior and exterior trims and functional components. In particular, with the recent rise in popularity of electric vehicles, where vehicle range is closely tied to vehicle weight, more engineering materials (PA6 / PA66 / ABS) are being replaced by lighter polypropylene.

[0003] However, compared to the aforementioned materials, polypropylene has disadvantages such as lower strength, tendency to whitish and crack when bent, and poor scratch resistance. For example, automotive interior window frames were originally made of PA6-GF15, which offers high bending toughness and scratch resistance. However, its high strength makes assembly difficult. Major OEMs are now switching from PA6-GF15 to PP-GF25 or PP-GF15. However, PP-GF has drawbacks such as severe surface fiber formation, whitish and cracking when bent, and poor scratch resistance, limiting its application in automotive interiors.

[0004] Therefore, it is urgent to develop a glass fiber reinforced polypropylene material with good appearance and resistance to bending cracking and scratch resistance.

[0005] Summary of the Invention

[0006] The object of the present invention is to overcome the deficiencies of the prior art and provide a glass fiber reinforced polypropylene material having good appearance and resistance to bending, cracking and scratching.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] In a first aspect, the present invention provides a polypropylene composite material comprising the following components in parts by weight: 59 to 90 parts of polypropylene resin, 5 to 15 parts of high-density polyethylene resin, 5 to 10 parts of 1-octene-ethylene block copolymer, 5 to 10 parts of ethylene-propylene copolymer, 5 to 15 parts of glass fiber, and 0.05 to 2 parts of a nucleating agent.

[0009] The inventors of the present invention have discovered that the present invention uses a compound of 1-octene-ethylene block copolymer (OBC) and ethylene-propylene copolymer (POE) as a toughening agent, which can make the glass fiber reinforced polypropylene composite material have high rigidity and toughness at the same time, thereby improving its resistance to bending cracking. At the same time, the addition of high-density polyethylene resin can improve the compatibility between the components, making the glass fiber evenly dispersed in the polypropylene resin, and giving the polypropylene composite material a good appearance, effectively avoiding the problem of glass fiber agglomeration and poor appearance in the resin due to the large difference in rheological properties between the polypropylene resin and the toughening agent. However, when the amount of 1-octene-ethylene block copolymer is too high, the surface hardness of the part is reduced, the ability to resist external damage is reduced, and the scratch resistance is reduced. When the amount of 1-octene-ethylene block copolymer is too low, the toughness of the material system is reduced, and the part is prone to bending cracking.

[0010] As a preferred embodiment of the polypropylene composite material of the present invention, the mass ratio of 1-octene-ethylene block copolymer to ethylene-propylene copolymer is 1-octene-ethylene block copolymer:ethylene-propylene copolymer=1:1 to 1:2.

[0011] The inventors of the present invention have found that when the mass ratio of OBC to POE in the present invention is within the above-mentioned range, the polypropylene composite material can have more excellent resistance to bending cracking, and POE can give the polypropylene composite material higher toughness. After compounding with OBC, the OBC material has good rebound performance, so that the surface of the material can be partially restored after external damage, thereby improving the scratch resistance of the part.

[0012] As a preferred embodiment of the polypropylene composite material of the present invention, the 1-octene-ethylene block copolymer has a melt flow rate of 0.5 to 44 g / 10 min, as measured at 190°C and a 2.16 kg weight according to ISO 1133-2011; the ethylene-propylene copolymer has a melt flow rate of 1.3 to 21 g / 10 min, as measured at 190°C and a 2.16 kg weight according to ISO 1133-2011.

[0013] As a more preferred embodiment of the polypropylene composite material of the present invention, the 1-octene-ethylene block copolymer has a melt flow rate of 1 to 30 g / 10 min, as measured at 190 ° C. and a 2.16 kg weight according to ISO 1133-2011; the ethylene-propylene copolymer has a melt flow rate of 3.6 to 18 g / 10 min, as measured at 190 ° C. and a 2.16 kg weight according to ISO 1133-2011.

[0014] The inventors of the present invention have discovered that, by compounding a 1-octene-ethylene block copolymer and an ethylene-propylene copolymer having a specific melt flow rate, and compounding them with high-density polyethylene, the present invention can, on the one hand, improve the dispersibility of glass fibers in the polypropylene resin, thereby imparting a good appearance to the composite material. Furthermore, by compounding the 1-octene-ethylene block copolymer and the ethylene-propylene copolymer, within a specific flowability range, the two types of elastomers can be pulled against each other, presenting a highly stretched state within the polypropylene matrix, thereby enhancing the toughness of the polypropylene composite material and imparting better resistance to bending and cracking.

[0015] As a preferred embodiment of the polypropylene composite material of the present invention, the nucleating agent includes at least one of acetylene black, metal phosphate nucleating agents, and substituted aromatic phosphate nucleating agents.

[0016] The inventors of the present invention conducted experimental studies on a large number of nucleating agents and found that the use of the above-mentioned nucleating agent of the present invention is beneficial to improving the crystallization temperature and crystallinity of the composite material, enhancing the rigidity of the surface of the polypropylene composite material, thereby making it have better scratch resistance.

[0017] As a more preferred embodiment of the polypropylene composite material of the present invention, the nucleating agent includes acetylene black, a metal phosphate nucleating agent, and a substituted aromatic phosphate nucleating agent; the mass ratio of the acetylene black, the metal phosphate nucleating agent, and the substituted aromatic phosphate nucleating agent is (0.5-1.5):(0.05-0.5):(0.005-0.5).

[0018] The inventors of the present invention have discovered that the aforementioned nucleating agents, when combined in the present invention, can enhance the crystallinity and crystallization rate of the material, thereby increasing its rigidity, particularly significantly improving its surface hardness and thus its scratch resistance. Substituted aryl phosphate nucleating agents can significantly increase its toughness without reducing its rigidity, thereby improving its flexural resistance. The present invention utilizes these three nucleating agents to synergistically improve the flexural and scratch resistance of glass fiber reinforced polypropylene materials.

[0019] As the most preferred embodiment of the polypropylene composite material of the present invention, the mass ratio of the acetylene black, the metal phosphate nucleating agent, and the substituted aromatic phosphate nucleating agent is (0.5-1):(0.275-0.5):(0.005-0.2).

[0020] The inventors have found through a large number of experiments that when the mass ratio of the nucleating agent of the present invention is within the above preferred range, the final glass fiber reinforced polypropylene material can have better bending resistance and scratch resistance.

[0021] As a preferred embodiment of the polypropylene composite material of the present invention, the average length of the glass fiber is 3.0 to 4.5 mm, and the diameter of the glass fiber is 10 to 15 μm.

[0022] As a more preferred embodiment of the polypropylene composite material of the present invention, the average length of the glass fiber is 4.5 mm, and the diameter of the glass fiber is 13 μm.

[0023] The inventors of the present invention have discovered that the use of glass fibers with the above-mentioned average length and diameter can enable the material to maintain a certain rigidity, resist external forces during bending, and reduce the risk of bending and cracking; at the same time, appropriate length and diameter can make the glass fibers evenly distributed on the surface of the material, increase the surface hardness of the material, and thus make the composite material have better resistance to bending, cracking and scratching.

[0024] As a preferred embodiment of the polypropylene composite material of the present invention, at least one of the following (I) to (II) is satisfied:

[0025] (I) The high-density polyethylene resin has a melt flow rate of 0.35 to 30 g / 10 min and a density of 0.951 to 0.956 g / cm3 as measured at 190°C and a 2.16 kg weight according to ISO 1133-2011. 3 ;

[0026] (II) The polypropylene resin comprises at least one of homopolypropylene and copolymer polypropylene; the polypropylene resin has a melt flow rate of 0.4 to 50 g / 10 min as measured at 230° C. and a 2.16 kg weight in accordance with ISO 1133-2011.

[0027] The inventors of the present invention have found that the high-density polyethylene with the above-mentioned specific density and melt flow rate of the present invention has better flexibility, making the polypropylene composite material easier to distribute on the surface of the material during the injection molding process, thereby achieving the effect of improving the appearance.

[0028] As a more preferred embodiment of the polypropylene composite material of the present invention, the high-density polyethylene resin has a melt flow rate of 0.7 to 20 g / 10 min, measured at 190°C and a 2.16 kg weight in accordance with ISO 1133-2011. The inventors have found, through extensive research, that the melt flow rate of the high-density polyethylene resin is most flexible within this preferred range, enabling the prepared polypropylene composite material to be bent at a 120° angle without whitening or cracking, and having a scratch resistance of ≤0.5.

[0029] As a preferred embodiment of the polypropylene composite material of the present invention, the polypropylene composite material further comprises the following components in parts by weight: 0.05 to 0.5 parts of a primary antioxidant, 0.05 to 0.5 parts of an auxiliary antioxidant, and 0.5 to 5 parts of a compatibilizer.

[0030] As a preferred embodiment of the polypropylene composite material of the present invention, the primary antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; and the auxiliary antioxidant is tris(2,4-di-tert-butylphenyl)phosphite.

[0031] As a preferred embodiment of the polypropylene composite material of the present invention, the compatibilizer is maleic anhydride grafted polypropylene.

[0032] In a second aspect, the present invention further provides a method for preparing the above-mentioned polypropylene composite material, comprising the following steps:

[0033] S1, weighing the components of the polypropylene composite material in proportion, mixing them evenly to obtain a premix;

[0034] S2. Melt-extrude, granulate and dry the premix in step S1 to obtain the polypropylene composite material.

[0035] As a preferred embodiment of the preparation method of the present invention, the process parameters of the melt extrusion are: the temperature of zone 1 is 80°C, the temperature of zone 2 is 190°C, the temperature of zone 3 is 190°C, the temperature of zone 4 is 190°C, the temperature of zone 5 is 190°C, the temperature of zone 6 is 190°C, the temperature of zone 7 is 190°C, the temperature of zone 8 is 190°C, the temperature of zone 9 is 190°C, and the speed of the main engine is 450 rpm.

[0036] In a third aspect, the present invention further provides the use of the above-mentioned polypropylene composite material in the preparation of automotive decorative materials.

[0037] The inventors of the present invention have found through research that the polypropylene composite material of the present invention has good appearance, excellent scratch resistance and resistance to bending and cracking, can be used to prepare automotive decorative materials, and has good application prospects.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] (1) The present invention adopts a compound of 1-octene-ethylene block copolymer and ethylene-propylene copolymer as a toughening agent, which can make the glass fiber reinforced polypropylene composite resin have high rigidity and toughness at the same time, thereby improving its resistance to bending cracking; at the same time, the addition of the high-density polyethylene resin of the present invention can improve the compatibility between the components, make the glass fiber dispersed evenly in the polypropylene resin, and make the polypropylene composite material have a good appearance, effectively avoiding the problem of glass fiber agglomeration and poor appearance in the resin caused by the large difference in rheological properties between the polypropylene resin and the toughening agent;

[0040] (2) The present invention uses a 1-octene-ethylene block copolymer and an ethylene-propylene copolymer with a specific melt flow rate to be compounded, and at the same time compounded with high-density polyethylene. On the one hand, it can improve the dispersibility of glass fiber in polypropylene resin, so that the composite material has a more excellent appearance; on the other hand, it can improve the toughness of the polypropylene composite material, so that it has better resistance to bending cracking;

[0041] (3) The present invention adopts specific nucleating agents to be compounded in a ratio, wherein acetylene carbon black and metal phosphate nucleating agents can improve the crystallinity and crystallization rate of the material, thereby improving the rigidity of the material, especially significantly improving the surface hardness of the material, thereby improving the scratch resistance of the material; and substituted aromatic phosphate nucleating agents can significantly improve the toughness of the material without reducing the rigidity of the material, thereby improving the bending resistance of the material. The present invention adopts the above three nucleating agents to work together to synergistically improve the bending resistance and scratch resistance of glass fiber reinforced polypropylene materials. DETAILED DESCRIPTION

[0042] The technical solutions of the present invention are further described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The methods or operations used in the embodiments, unless otherwise specified, are conventional methods or routine operations in the art.

[0043] Unless otherwise specified, the materials, reagents, and the like used in the Examples and Comparative Examples of the present invention are commercially available. The primary antioxidant used in the following Examples and Comparative Examples of the present invention is commercially available pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], the secondary antioxidant is commercially available tris(2,4-di-tert-butylphenyl)phosphite, and the compatibilizer is commercially available maleic anhydride-grafted polypropylene with a melt flow rate of 20 g / 10 min (test conditions: 190°C, 2.16 kg, ISO 1133-2011).

[0044] The raw materials used in the examples and comparative examples are described below, but are not limited to these materials:

[0045] Polypropylene resin 1 (PP1): PPB8101, Yanshan Petrochemical, melt flow rate: 0.4 g / 10 min (test conditions: 230°C, 2.16 kg, ISO 1133-2011).

[0046] Polypropylene resin 2 (PP2): PP EP548R, CNOOC Shell, melt flow rate: 30 g / 10 min (test conditions: 230° C., 2.16 kg, ISO 1133-2011).

[0047] Polypropylene resin 3 (PP3): PP EP5075X, Sinopec, melt flow rate 50 g / 10 min (test conditions: 230° C., 2.16 kg, ISO 1133-2011).

[0048] High-density polyethylene resin 1 (HDPE1): HDPE HYA600, ExxonMobil, melt flow rate 0.35 g / 10 min (test conditions: 190°C, 2.16 kg, ISO 1133-2011), density 0.954 g / cm 3 .

[0049] High-density polyethylene resin 2 (HDPE2): HDPE 5000S, Daqing Petrochemical, melt flow rate 0.7 g / 10 min (test conditions: 190°C, 2.16 kg, ISO 1133-2011), density 0.951 g / cm 3 .

[0050] High-density polyethylene resin 3 (HDPE3): HDPE 5421B, CNOOC Shell, melt flow rate 10 g / 10 min (test conditions: 190°C, 2.16 kg, ISO 1133-2011), density 0.953 g / cm 3 .

[0051] High-density polyethylene resin 4 (HDPE4): HDPE HMA016, ExxonMobil, melt flow rate 20 g / 10 min (test conditions: 190°C, 2.16 kg, ISO 1133-2011), density 0.956 g / cm 3 .

[0052] High-density polyethylene resin 5 (HDPE5): HDPE HMA018, ExxonMobil, melt flow rate 30 g / 10 min (test conditions: 190°C, 2.16 kg, ISO 1133-2011), density 0.954 g / cm3 .

[0053] Low-density polyethylene resin: LDPE2426K, Maoming Petrochemical, melt flow rate 4g / 10min (test conditions: 190℃, 2.16kg, ISO 1133-2011), density 0.926g / cm 3 .

[0054] 1-Octene-ethylene block copolymer 1 (OBC1): INFUSE OBC 9010, Dow Chemical, melt flow rate of 0.5 g / 10 min (test conditions: 190° C., 2.16 kg, ISO 1133-2011).

[0055] 1-Octene-ethylene block copolymer 2 (OBC2): INFUSE OBC 9107, Dow Chemical, melt flow rate: 1 g / 10 min (test conditions: 190° C., 2.16 kg, ISO 1133-2011).

[0056] 1-Octene-ethylene block copolymer 3 (OBC3): INFUSE OBC 9807, Dow Chemical, melt flow rate of 15 g / 10 min (test conditions: 190° C., 2.16 kg, ISO 1133-2011).

[0057] 1-Octene-ethylene block copolymer 4 (OBC4): INFUSE OBC 9900, Dow Chemical, melt flow rate of 30 g / 10 min (test conditions: 190° C., 2.16 kg, ISO 1133-2011).

[0058] 1-Octene-ethylene block copolymer 5 (OBC5): INFUSE OBC 10510, melt flow rate of 44 g / 10 min (test conditions: 190° C., 2.16 kg, ISO 1133-2011).

[0059] Ethylene-propylene copolymer 1 (POE1): Vistamaxx POP 7010FL, ExxonMobil, melt flow rate of 1.3 g / 10 min (test conditions are 190° C., 2.16 kg, ISO 1133-2011).

[0060] Ethylene-propylene copolymer 2 (POE2): Vistamaxx POP 3980FL, ExxonMobil, melt flow rate of 3.6 g / 10 min (test conditions are 190° C., 2.16 kg, ISO 1133-2011).

[0061] Ethylene-propylene copolymer 3 (POE3): Vistamaxx POP 6202, ExxonMobil, melt flow rate 9 g / 10 min (test conditions: 190° C., 2.16 kg, ISO 1133-2011).

[0062] Ethylene-propylene copolymer 4 (POE4): Vistamaxx POP 7050BF, ExxonMobil, melt flow rate of 18 g / 10 min (test conditions are 190° C., 2.16 kg, ISO 1133-2011).

[0063] Ethylene-propylene copolymer 5 (POE5): Vistamaxx POP 6502, ExxonMobil, melt flow rate of 21 g / 10 min (test conditions are 190° C., 2.16 kg, ISO 1133-2011).

[0064] Acetylene black: Acetylene black DENKABLACK, Shanghai Zhongrong.

[0065] Phosphate metal salt nucleating agent 1: Nucleating agent NP-509, Beijing Jihaichuan Technology Development Co., Ltd.

[0066] Phosphate metal salt nucleating agent 2: NAA-325. Guangzhou Chenghe Technology Co., Ltd.

[0067] Substituted aryl phosphate nucleating agent 1: TMP-5, Shanxi Chemical Research Institute.

[0068] Substituted aryl phosphate nucleating agent 2: TMB-5, Shanxi Chemical Research Institute.

[0069] Polyolefin β-crystal nucleating agent: NB-328, Hubei Xinyuhong Biopharmaceutical Technology Co., Ltd.

[0070] Glass fiber: ECS13-4.5-508A, Jushi glass fiber, average length 4.5mm, diameter 13μm.

[0071] Examples 1 to 24 and Comparative Examples 1 to 12

[0072] Examples 1 to 24 are polypropylene composite materials of the present invention. The components and weight proportions of the polypropylene composite materials of Examples 1 to 24 and Comparative Examples 1 to 12 are shown in Tables 1 to 5.

[0073] The preparation method of the polypropylene composite material of Examples 1 to 24 and Comparative Examples 1 to 12 comprises the following steps:

[0074] S1, weighing the components of the polypropylene composite material in proportion, mixing them evenly to obtain a premix;

[0075] S2. Placing the premix described in step S1 into a twin-screw extruder for melt extrusion and granulation drying to obtain the polypropylene composite material; the process parameters of the melt extrusion are: the temperature of zone 1 is 80° C., the temperature of zone 2 is 190° C., the temperature of zone 3 is 190° C., the temperature of zone 4 is 190° C., the temperature of zone 5 is 190° C., the temperature of zone 6 is 190° C., the temperature of zone 7 is 190° C., the temperature of zone 8 is 190° C., the temperature of zone 9 is 190° C., and the speed of the main engine is 450 rpm; the aspect ratio of the twin-screw extruder is 48:1.

[0076] Table 1 Weight parts: parts

[0077] Table 2 Weight parts: parts

[0078] Table 3 Weight parts: parts

[0079] Table 4 Weight parts: parts

[0080] Table 5 Weight parts: parts

[0081] Effect Examples

[0082] The polypropylene composite materials of Examples 1-24 and Comparative Examples 1-12 were respectively formed into 100mm*100m*3mm square plates and Volkswagen K31 leather grain plates for evaluating appearance. The polypropylene composite materials of Examples 1-24 and Comparative Examples 1-12 were prepared into ISO standard 1A tensile test strips for evaluating bend whitening performance. The polypropylene composite materials of Examples 1-24 and Comparative Examples 1-12 were prepared into Volkswagen K31 leather grain for evaluating the scratch resistance of the materials. The test methods are as follows:

[0083] (1) Appearance grade

[0084] Test method: visual inspection;

[0085] Evaluation criteria: (1) Grade A: no floating fibers on the surface of the smooth board, no floating fibers on the K31 leather grain board; (2) Grade B: a small amount of floating fibers can be seen on the surface of the smooth board, no floating fibers can be seen on the K31 leather grain board; (3) Grade C: obvious floating fibers can be seen on the surface of the smooth board, a small amount of floating fibers can be seen on the K31 leather grain board;

[0086] Performance requirements: Appearance grade ≥ B.

[0087] (2) Resistance to bending and cracking

[0088] Test method: Bend the ISO standard 1A spline at both ends to 45 degrees, 90 degrees, and 120 degrees respectively, and observe whether there are cracks or whitening problems at the bends;

[0089] Performance requirements: Bending angle ≥ 90°, no cracking or whitening at the bending point.

[0090] (3) Scratch resistance

[0091] Test method: Using the Volkswagen Group PV3974 standard, use a 3N weight to scratch a hair (16.0mm) disc with a contact radius of 0.5mm. 80 parallel marks are made on the surface of the sample. The gloss change at the scratched area is determined to be ≤0.6.

[0092] Performance requirements: The standard requires that the glossiness before and after scratching DGG ≤ 0.6.

[0093] The test results are shown in Tables 6 and 7 below.

[0094] Table 6

[0095] Table 7

[0096] As can be seen from Tables 6 and 7, when the technical solution of the present invention is adopted, the obtained products have good appearance, excellent bending crack resistance and scratch resistance, and the appearance grade can reach Class B or above. When the bending angle is ≥90°, there is no cracking or whitening at the bending part of the product, and the scratch resistance is ≤0.6.

[0097] Comparison of Examples 1 to 9 with Comparative Examples 1 to 2 shows that the melt flow rates of the 1-octene-ethylene block copolymer and the ethylene-propylene copolymer significantly affect the appearance, bending resistance, and scratch resistance of the product. When the melt flow rate of the 1-octene-ethylene block copolymer is 1-30 g / 10 min (190°C, 2.16 kg weight conditions, ISO 1133-2011), the appearance grade of the polypropylene composite material reaches Class A, and when the bending angle can reach 120°, there is no cracking or whitening at the bend. At the same time, when the melt flow rate of the ethylene-propylene copolymer is 3.6-18 g / 10 min (190°C, 2.16 kg weight conditions, ISO 1133-2011), the comprehensive performance of the obtained polypropylene composite material is even better.

[0098] By comparing Example 3, Examples 10 to 12 and Comparative Examples 3 to 4, it can be seen that when the mass ratio of 1-octene-ethylene block copolymer to ethylene-propylene copolymer is 1:1 to 1:2, the appearance grade of the polypropylene composite material can reach Class A, and has better appearance performance.

[0099] Comparison of Example 3, Examples 13-16, and Comparative Examples 5-6 shows that the polypropylene composites prepared by compounding the nucleating agent with acetylene black, a metal phosphate nucleating agent, and a substituted aryl phosphate nucleating agent in a specific ratio exhibit excellent scratch resistance and can significantly improve the surface rigidity of the polypropylene composite, thereby exhibiting even better scratch resistance. In particular, the polypropylene composites prepared in Examples 3, 13, and 14 exhibit even better bending resistance, with no cracking or whitening occurring at the bend when the bending angle reaches 120°. Comparison of Example 3 and Example 17 shows that compounding the substituted aryl phosphate nucleating agent described in the present invention with acetylene black and a metal phosphate nucleating agent exhibits even better scratch resistance. Comparison of Example 3 with Comparative Examples 7 and 8 shows that omitting the nucleating agent or adding an excessive amount of nucleating agent results in decreased bending and scratch resistance of the polypropylene composite.

[0100] By comparing Example 3, Examples 18-21, and Comparative Example 10, it can be seen that when the melt flow rate (190°C, 2.16 kg weight conditions, ISO 1133-2011) of the high-density polyethylene resin is 0.7 to 20 g / 10 min, the prepared polypropylene composite material does not show whitening or cracking at the bend when the bending angle is 120°, and the scratch resistance is ≤0.5; by comparing Example 3 and Comparative Example 9, it can be seen that, compared with the low-density polyethylene resin, the high-density polyethylene resin of the present invention can make the appearance of the polypropylene composite material reach Class A, and has more excellent bending crack resistance and scratch resistance.

[0101] Comparing Example 3 and Comparative Examples 11-12, it can be seen that when the weight parts of high-density polyethylene resin are 5 to 15 parts, the appearance performance of the polypropylene composite material reaches Class A, and the scratch resistance is 0.3, with good appearance and better scratch resistance.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution 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 the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A polypropylene composite material, characterized in that: The invention comprises the following components in parts by weight: 59-90 parts of polypropylene resin, 5-15 parts of high-density polyethylene resin, 5-10 parts of 1-octene-ethylene block copolymer, 5-10 parts of ethylene-propylene copolymer, 5-15 parts of glass fiber and 0.05-2 parts of nucleating agent.

2. The polypropylene composite material according to claim 1, characterized in that The mass ratio of the 1-octene-ethylene block copolymer to the ethylene-propylene copolymer is 1-octene-ethylene block copolymer:ethylene-propylene copolymer=1:1-1:

2.

3. The polypropylene composite material according to claim 1, characterized in that: The melt flow rate of the 1-octene-ethylene block copolymer measured at 190° C. and 2.16 kg weight according to ISO 1133-2011 is 0.5-44 g / 10 min; the melt flow rate of the ethylene-propylene copolymer measured at 190° C. and 2.16 kg weight according to ISO 1133-2011 is 1.3-21 g / 10 min.

4. The polypropylene composite material according to claim 1, characterized in that: The nucleating agent includes at least one of acetylene black, metal phosphate nucleating agents, and substituted aromatic phosphate nucleating agents.

5. The polypropylene composite material according to claim 4, characterized in that: The nucleating agent includes acetylene black, metal phosphate nucleating agent, and substituted aromatic phosphate nucleating agent; the mass ratio of the acetylene black, metal phosphate nucleating agent, and substituted aromatic phosphate nucleating agent is (0.5-1.5):(0.05-0.5):(0.005-0.5).

6. The polypropylene composite material according to claim 1, characterized in that: The average length of the glass fiber is 3.0-4.5 mm, and the diameter of the glass fiber is 10-15 μm.

7. The polypropylene composite material according to claim 1, characterized in that: Satisfy at least one of the following (I) to (II): (I) The high-density polyethylene resin has a melt flow rate of 0.35-30 g / 10 min and a density of 0.951-0.956 g / cm2 as measured at 190°C and 2.16 kg weight according to ISO 1133-2011. 3 ; (II) The polypropylene resin comprises at least one of homopolypropylene and copolymer polypropylene; the melt flow rate of the polypropylene resin is 0.4 to 50 g / 10 min at 230° C. and 2.16 kg weight as tested in accordance with ISO 1133-2011.

8. The polypropylene composite material according to claim 1, characterized in that: The invention also comprises the following components in parts by weight: 0.05 to 0.5 parts of a main antioxidant, 0.05 to 0.5 parts of an auxiliary antioxidant, and 0.5 to 5 parts of a compatibilizer.

9. The method for preparing a polypropylene composite material according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, weighing the components for preparing the polypropylene composite material according to proportion, mixing them evenly to obtain a premix; S2, melt-extrude the premixed material in step S1, granulate and dry to obtain the polypropylene composite material.

10. Use of the polypropylene composite material according to any one of claims 1 to 8 or the polypropylene composite material obtained by the preparation method according to claim 9 in the preparation of automotive interior or exterior materials.

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