Low-gloss polypropylene composite material as well as preparation method and application thereof

Abstract

The invention provides a low-gloss polypropylene composite material as well as a preparation method and application thereof, and belongs to the technical field of plastic modification. The low-gloss polypropylene composite material is prepared from the following components in parts by weight: 53 to 75 parts of polypropylene resin, 15 to 30 parts of inorganic filler, 5 to 10 parts of metallocene polyethylene, 3 to 5 parts of polyolefin elastomer, 0.8 to 1.8 parts of dendritic compatilizer and 1 to 1.5 parts of other auxiliaries. The low-gloss polypropylene composite material disclosed by the invention has the advantages of low glossiness, excellent rigid-tough balance performance, good processing flowability and low modification cost.

Description

Technical Field

[0001] The invention belongs to the technical field of plastic modification, and in particular relates to a low-gloss polypropylene composite material and a preparation method and application thereof. Background Art

[0002] Polypropylene (PP) has excellent comprehensive performance, low density and low cost. It has become the largest and most widely used polymer variety in automotive plastics. It is mainly used in automotive interior and exterior parts such as bumpers, dashboards, door trim panels, air conditioning parts and battery housings. With the rapid development of the automotive industry, safety, comfort, light weight, energy saving and green environmental protection have become the main development direction of the automotive industry. In recent years, when low-gloss and low-hardness PP composite materials are used in automotive interior parts, they can make the light inside the car soft and will not produce obvious mirror reflections, reducing interference to the driver's vision and increasing driving safety and comfort. At the same time, low-gloss PP composite materials can reduce the plastic feel to a certain extent and enhance the user's sensory experience, and are increasingly favored by the market.

[0003] Gloss is a physical quantity that evaluates the ability of a material surface to reflect light under a set of geometric conditions. Gloss meters are usually used to measure gloss. The commonly used detection geometric angles of gloss meters are 20°, 45°, 60°, 75°, and 85°, and the 60° geometric angle has the widest application range. Gloss (specular gloss) is divided according to the 60° geometric angle. Gloss above 70.0 is high gloss; gloss between 30.0-70.0 is medium gloss; and gloss below 30.0 is low gloss.

[0004] Polypropylene is a semi-crystalline material with high gloss. It is often technically difficult to reduce the gloss of polypropylene while maintaining the comprehensive mechanical properties of the material. The existing technology usually adds components such as matting agents to adjust the gloss, and adds inorganic substances to increase the modulus and reduce the shrinkage rate. However, the impact performance decreases significantly with the increase in the amount of inorganic filling. Therefore, it is necessary to add the expensive polyolefin elastomer POE to increase the toughness, but the greater the amount of POE added, the greater the modification cost. The existing technologies CN109575427A, CN103073785B and CN102532774B have problems such as complex formula, unstable quality, poor product performance and high cost. Summary of the invention

[0005] In view of the deficiencies of the prior art, the object of the present invention is to provide a low-gloss polypropylene composite material, which has low gloss, excellent rigidity-toughness balance and good processing flowability, while having low modification cost.

[0006] In order to achieve the above object, according to one aspect of the present invention, a low-gloss polypropylene composite material is provided, comprising the following components in parts by weight: Polypropylene resin 53-75 parts; 15-30 parts of inorganic filler; Metallocene polyethylene 5-10 parts; 3-5 parts of polyolefin elastomer; Dendritic compatibilizer 0.8-1.8 parts; Other additives 1-1.5 parts.

[0007] In some embodiments, the polypropylene resin is a copolymer of propylene and ethylene, and the polypropylene resin has a melt mass flow rate (MFR) of 8-40 g / 10 min under the test conditions of 230° C. and a load of 2.16 kg.

[0008] In some embodiments, the inorganic filler is selected from one or more of silica, talc, chopped glass fibers, calcium carbonate, mica, or kaolin.

[0009] In some embodiments, the metallocene polyethylene has a melt mass flow rate (MFR) of 0.5-15 g / 10 min under the test conditions of 190° C. and a load of 2.16 kg.

[0010] In some embodiments, the polyolefin elastomer has a melt mass flow rate (MFR) of 0.5-10 g / 10 min under the test conditions of 190° C. and a load of 2.16 kg.

[0011] In some embodiments, the dendritic compatibilizer contains a polyethylene fatty chain with 30-80 carbon atoms and a polar group, wherein the polar group includes one or more of an amide group, a hydroxyl group or a carboxyl group, and the weight average molecular weight of the dendritic compatibilizer is 1500-7500.

[0012] In some embodiments, the other additives include one or more of antioxidants, antistatic agents, and masterbatches.

[0013] According to another aspect of the present invention, there is also provided a method for preparing the low-gloss polypropylene composite material as described above, comprising the following steps: (1) Weighing the inorganic filler, metallocene polyethylene, polyolefin elastomer and dendritic compatibilizer in proportion, mixing them evenly, and adding the evenly mixed materials into a twin-screw extruder for melt extrusion and granulation; (2) The polypropylene resin, other additives and the material obtained in step (1) are weighed in proportion and mixed evenly, and the evenly mixed material is added to a twin-screw extruder for melt extrusion and granulation to obtain the low-gloss polypropylene composite material.

[0014] In some embodiments, in step (1), the highest section temperature of the twin-screw extruder is 160-180°C, the main extruder speed is 200-280r / min, and the feed speed is 15-25r / min; In some embodiments, in step (2), the highest section temperature of the twin-screw extruder is 160-200°C, the main extruder speed is 230-300 r / min, and the feed speed is 20-35 r / min.

[0015] According to another aspect of the present invention, the present invention also provides the use of the low-gloss polypropylene composite material or the low-gloss polypropylene composite material prepared by the above preparation method in automobile interior decoration parts and small household appliances.

[0016] Compared with the prior art, the beneficial technical effects of the present invention are: (1) The present invention adds metallocene polyethylene, polyolefin elastomer and dendritic compatibilizer with specific properties to a specific polypropylene resin. The components work synergistically to change the crystallization behavior of polypropylene, significantly reduce the glossiness of the polypropylene composite material, and reduce the modification cost.

[0017] (2) The polypropylene composite material described in the present invention has a very low gloss, with a mirror gloss of less than 22 and a corresponding leather gloss of less than 2. It also has excellent rigidity-toughness balance and good processing flowability, and can be applied to components such as automobile instrument panels and automobile door interior panels, and can also be applied to small household appliances and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings.

[0019] Figure 1 The X-ray diffraction patterns of the polypropylene composite materials and the PP blank samples prepared in Example 1 and Comparative Example 1 of the present invention are shown. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0021] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0022] Herein, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all substitutes, improvements and equivalents of the methods and materials described in the present invention can be included in the scope limited by the claims.

[0023] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0024] The invention provides a low-gloss polypropylene composite material, which comprises the following components: polypropylene resin, inorganic filler, metallocene polyethylene, polyolefin elastomer, dendritic compatibilizer and other additives.

[0025] In the present invention, the weight proportion of the polypropylene resin is 53-75 parts, preferably 55-70 parts, and more preferably 60-65 parts.

[0026] The polypropylene resin is a copolymer of propylene and ethylene, wherein the content of the ethylene comonomer is 7-13wt%. The melt mass flow rate MFR of the polypropylene resin under the test conditions of 230° C. and a load of 2.16kg is 8-40g / 10min. It can be understood that the melt mass flow rate MFR can be any specific value of 8g / 10min, 10g / 10min, 12g / 10min, 14g / 10min, 16g / 10min, 18g / 10min, 20g / 10min, 22g / 10min, 24g / 10min, 26g / 10min, 28g / 10min, 30g / 10min, 32g / 10min, 34g / 10min, 36g / 10min, 38g / 10min, 40g / 10min, or any value within the range of 8-40g / 10min. The polypropylene resin of the present invention contains a certain amount of ethylene comonomer, has good melt fluidity and high impact toughness, and can be more evenly mixed with metallocene polyethylene, polyolefin elastomer and dendritic polymer with specific properties to obtain a polypropylene composite material with low gloss and high impact resistance.

[0027] In the present invention, the weight proportion of the inorganic filler is 15-30 parts.

[0028] The inorganic filler is selected from one or more of silicon dioxide, talc, chopped glass fiber, calcium carbonate, mica or kaolin. The present invention has no specific restrictions on the particle size of the inorganic filler, and the conventional particle size in the art can be adopted, for example, the average particle size of the inorganic filler can be 2.5-10 μm. In the present invention, the addition of inorganic substances can change the crystallinity of polypropylene and effectively reduce the surface gloss.

[0029] In the present invention, the weight proportion of the metallocene polyethylene is 5-10 parts, preferably 6-9 parts, and more preferably 6-8 parts.

[0030] The metallocene polyethylene is a copolymer of ethylene and α-olefin, and the α-olefin comonomer may be one or more of butene, hexene or octene, preferably hexene. The melt mass flow rate MFR of the metallocene polyethylene described in the present invention under the test conditions of 190° C. and a load of 2.16 kg is 0.5-15 g / 10 min. It can be understood that the melt mass flow rate MFR can be any specific value among 0.5 g / 10 min, 1 g / 10 min, 2 g / 10 min, 3 g / 10 min, 4 g / 10 min, 5 g / 10 min, 6 g / 10 min, 7 g / 10 min, 8 g / 10 min, 9 g / 10 min, 10 g / 10 min, 11 g / 10 min, 12 g / 10 min, 13 g / 10 min, 14 g / 10 min, and 15 g / 10 min, or any value within the range of 0.5-15 g / 10 min; the density of the metallocene polyethylene is 0.912-0.916 g / cm 3 .

[0031] The inventors have found through a large number of experimental studies that the addition of metallocene polyethylene with specific physical properties can effectively change the peak height ratio and grain size of the polypropylene diffraction peak, thereby effectively changing the crystallization behavior and gloss of polypropylene, while metallocene polyethylene beyond the above-mentioned range of physical properties has no obvious effect on reducing gloss.

[0032] In the present invention, the weight proportion of the polyolefin elastomer is 3-5 parts, preferably 3.5-5 parts.

[0033] The polyolefin elastomer of the present invention has a melt mass flow rate (MFR) of 0.5-10 g / 10 min, more preferably 0.5-5 g / 10 min, at 190° C. and a load of 2.16 kg. The density of the polyolefin elastomer is 0.860-0.890 g / cm 3, Mooney viscosity (ML1+4@121℃) is greater than 8, preferably greater than 10, and more preferably greater than 20. The inventors have found through a large number of experimental studies that by preferably selecting polyolefin elastomers with lower MFR and higher viscosity, a synergistic effect can be exerted with metallocene polyethylene and dendritic compatibilizers with specific properties, and the three can synergistically adjust the gloss of polypropylene, while other polyolefin elastomers beyond the above range of physical properties have no obvious effect on reducing gloss.

[0034] In the present invention, the weight proportion of the dendritic compatibilizer is 0.8-1.8 parts.

[0035] In the present invention, the dendritic compatibilizer contains polyethylene fatty chains and polar groups, and the molecular weight of the dendritic compatibilizer is 1500-7500, preferably 2000-7000, and more preferably 3000-5000; the number of carbon atoms of the polyethylene fatty chain in the dendritic compatibilizer of the present invention is 30-80, preferably 40-70, and more preferably 50-60; the polar groups in the dendritic compatibilizer include one or more of amide groups, hydroxyl groups or carboxyl groups, and preferably, the number of the polar groups is 8-16.

[0036] In the present invention, the weight proportion of the other auxiliary agents is 1-1.5 parts, preferably 1.1-1.3 parts.

[0037] In the present invention, the other auxiliary agents include one or more of antioxidants, antistatic agents, and masterbatches; specifically, the weight portion of the antioxidant is 0.1-0.2 parts, and the antioxidants include pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (antioxidant 1010), 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (antioxidant 1330), 1,3,5-tris[[4-(1,1-dimethylethyl)-3-hydroxy-2,6-dimethylphenyl]methyl]-1,3,5-triazine-2,4,6-trione (antioxidant 1790) , tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168), bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite (antioxidant 626) or 3,9-dioctadecyloxy-2,4,8,10-tetraoxy-3,9-diphosphaspiro[5.5]undecane (antioxidant 618) One or more; The weight portion of the antistatic agent is 0.05-0.1 parts, and the antistatic agent can be glyceryl monostearate. The present invention can use conventional commercially available antistatic agents; The weight portion of the masterbatch is 0.8-1.3 parts, and the present invention can use conventional commercially available masterbatch, for example, the masterbatch can be a black masterbatch.

[0038] The inventors found that by adding polyolefin elastomers, metallocene polyethylene and dendritic compatibilizers with specific properties to copolymerized polypropylene, the three can synergistically change the crystallization behavior of polypropylene, significantly reduce the glossiness of the polypropylene composite material, and at the same time reduce the modification cost.

[0039] The present invention also provides a method for preparing the low-gloss polypropylene composite material, comprising the following steps: (1) The inorganic filler, metallocene polyethylene, polyolefin elastomer and dendritic compatibilizer are weighed and mixed uniformly according to a certain proportion, and the uniformly mixed materials are added into a twin-screw extruder for melt extrusion and granulation.

[0040] (2) The polypropylene resin, other additives and the material obtained in step (1) are weighed in proportion and mixed evenly, and the evenly mixed material is added to a twin-screw extruder for melt extrusion and granulation to obtain the low-gloss polypropylene composite material.

[0041] In some embodiments, in step (1), the mixing is performed in a mixer, the rotation speed of the mixer is 1000-1500 r / min, and the mixing time is 1-3 min.

[0042] The present invention has no particular limitation on the type of the twin-screw extruder in step (1), and a conventional twin-screw extruder in the art may be used. For example, a co-rotating twin-screw extruder may be used, and the diameter of the twin-screw extruder may be 20 mm, and the aspect ratio may be 36:1.

[0043] In some embodiments, in step (1), the highest section temperature of the twin-screw extruder is 160-180°C, the main extruder speed is 200-280r / min, and the feed speed is 15-25r / min.

[0044] In some embodiments, in step (2), the mixing is carried out in a mixer, the rotation speed of the mixer is 1000-1500 r / min, and the stirring time is 1-3 min.

[0045] In some embodiments, in step (2), the highest section temperature of the twin-screw extruder is 160-200°C, the main extruder speed is 230-300 r / min, and the feed speed is 20-35 r / min.

[0046] The present invention has no particular limitation on the type of the twin-screw extruder in step (2), and a conventional twin-screw extruder in the art may be used. For example, a co-rotating twin-screw extruder may be used, and the diameter of the twin-screw extruder may be 25 mm, and the aspect ratio may be 40:1.

[0047] The present invention also provides the use of the low-gloss polypropylene composite material or the low-gloss polypropylene composite material prepared according to the preparation method in automobile interior decoration parts and small household appliances.

[0048] The present invention will be described in detail below by way of examples. It should be understood that the following examples are only used to further explain and illustrate the content of the present invention by way of example, and are not intended to limit the present invention.

[0049] The raw materials used in the examples and comparative examples of the present invention are all commercially available, and their specific information is as follows: Polypropylene resin QP83N, under the test conditions of 230℃ and load 2.16kg, has a melt mass flow rate MFR of 9g / 10min and a density of 0.9g / cm 3 , the comonomer is ethylene, the mass percentage of the comonomer is 10%, the manufacturer is Qilu Petrochemical; The melt mass flow rate MFR of polypropylene resin QP81N at 230°C and load 2.16 kg is 26 g / 10 min and the density is 0.9 g / cm 3 , the comonomer is ethylene, accounting for 12% of the mass of the comonomer, manufacturer: Qilu Petrochemical; Polypropylene resin K7726, under the test conditions of 230℃ and 2.16kg load, has a melt mass flow rate MFR of 29g / 10min and a density of 0.9g / cm 3 , the comonomer is ethylene, accounting for 8% by weight, manufacturer: Yanshan Petrochemical; Polypropylene resin EP400M, under the test conditions of 230℃ and load 2.16kg, has a melt mass flow rate MFR of 8.6g / 10min and a density of 0.9g / cm 3 , the comonomer is ethylene, accounting for 7.5% by weight, manufacturer: LyondellBasell; Metallocene polyethylene (mPE) M-7, under the test conditions of 190°C and a load of 2.16 kg, has a melt mass flow rate MFR of 12.2 g / 10 min and a density of 0.912 g / cm 3 , the comonomer is hexene, manufacturer: Qilu Petrochemical; Metallocene polyethylene (mPE) M-24, under the test conditions of 190°C and a load of 2.16 kg, has a melt mass flow rate MFR of 24 g / 10 min and a density of 0.92 g / cm 3 , the comonomer is hexene, manufacturer: Qilu Petrochemical; Metallocene polyethylene (mPE) F1306ZP, under the test conditions of 190°C and load 2.16kg, has a melt mass flow rate MFR of 0.8g / 10min and a density of 0.914g / cm 3 , the comonomer is hexene, manufacturer: Qilu Petrochemical; Metallocene polyethylene (mPE) F132Z, under the test conditions of 190°C and a load of 2.16 kg, has a melt mass flow rate MFR of 2 g / 10 min and a density of 0.913 g / cm 3 , the comonomer is hexene, manufacturer: Qilu Petrochemical; Polyolefin elastomer (POE) 5371, under the test conditions of 190°C and load 2.16 kg, the melt mass flow rate MFR is 5 g / 10 min and the density is 0.870 g / cm 3 , the comonomer is octene, manufacturer: ExxonMobil; Polyolefin elastomer (POE) 7467, under the test conditions of 190°C and load 2.16 kg, the melt mass flow rate MFR is 1.2 g / 10 min, and the density is 0.862 g / cm 3 , the comonomer is butene, manufacturer: Dow Chemical; Polyolefin elastomer (POE) 8402, under the test conditions of 190°C and load 2.16kg, has a melt mass flow rate MFR of 30g / 10min and a density of 0.902g / cm 3 , the comonomer is octene, manufacturer: Dow Chemical; Dendritic compatibilizer A: molecular weight 1500-2000, long carbon fatty chain with 38 carbon atoms, containing amide group, manufacturer: Manufacturer: Weihai Chenyuan Molecular New Materials Co., Ltd.; Dendritic compatibilizer B: molecular weight 3000-4000, long carbon fatty chain with 60 carbon atoms, containing hydroxyl groups, manufacturer: Manufacturer: Weihai Chenyuan Molecular New Materials Co., Ltd.; Dendritic compatibilizer C: molecular weight 500-1000, long carbon fatty chain with 22 carbon atoms, containing amide group, manufacturer: Manufacturer: Weihai Chenyuan Molecular New Materials Co., Ltd.; Black masterbatch: Brand: KO-3300, Manufacturer: Taiwan Gaozhan; Talc: 1250-5000 mesh, commercially available; Antioxidant: a mixture of antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate) and antioxidant 168 (tris[2,4-di-tert-butylphenyl]phosphite) in a mass ratio of 1:1, commercially available; Antistatic agent: glyceryl monostearate, commercially available.

[0050] Examples 1-6 The method for preparing the low-gloss polypropylene composite material described in Examples 1-6 of the present application comprises the following steps: (1) First, the inorganic filler, metallocene polyethylene mPE, polyolefin elastomer POE and dendritic compatibilizer are weighed according to the ratio in Table 1, and mixed evenly in a high-speed mixer at a speed of 1000-1500 r / min for 1-3 min. The mixed materials are added to a co-rotating twin-screw extruder with a diameter of 20 mm and an aspect ratio of 36:1 for melt mixing and granulation. The highest section temperature of the extruder is 160-180°C, the main speed of the extruder is 200-280 r / min, and the feeding speed is 15-25 r / min.

[0051] (2) Weigh polypropylene resin, antioxidant, antistatic agent, masterbatch and the material obtained in step (1) according to the proportion in Table 1, place them in a high-speed mixer and mix them evenly. The speed of the mixer is 1000-1500 r / min, and the stirring time is 1-3 min. The evenly mixed materials are added to a co-rotating twin-screw extruder with a diameter of 25 mm and an aspect ratio of 40:1 for melt mixing. The highest section temperature of the extruder is 160-200° C., the main speed of the extruder is 230-300 r / min, and the feeding speed is 20-35 r / min. The low-gloss polypropylene composite material is obtained by extrusion granulation.

[0052] Table 1 Distribution ratio of each group of Examples 1-6 (by weight) .

[0053] Comparative Examples 1-8 The preparation method of the polypropylene composite material described in Comparative Examples 1-8 is the same as the preparation method in Examples 1-6, except that the composition and ratio of each component in Comparative Examples 1-8 are different from those in the examples, and the specific component ratios are shown in Table 2. Among them, the difference between Comparative Example 1 and Example 1 is that metallocene polyethylene and polyolefin elastomer with different properties are used, and no compatibilizer is used; the difference between Comparative Example 2 and Example 2 is that polypropylene resin with different properties, as well as different metallocene polyethylene and compatibilizer are used; the difference between Comparative Example 3 and Example 3 is that only a single polyolefin elastomer is used; the difference between Comparative Example 4 and Example 4 is that metallocene polyethylene, polyolefin elastomer and compatibilizer with different properties are used; the difference between Comparative Example 5 and Example 5 is that metallocene polyethylene, polyolefin elastomer and polypropylene resin with different properties are used, and no compatibilizer is used; the difference between Comparative Example 6 and Example 6 is that only a single polyolefin elastomer is used; the difference between Comparative Example 7 and Example 1 is that metallocene polyethylene and polyolefin elastomer with different properties are used; the difference between Comparative Example 8 and Example 4 is that metallocene polyethylene and polyolefin elastomer with different properties are used.

[0054] Table 2 Comparative Examples 1-8 Distribution Ratios (by weight) .

[0055] Performance Test: The polypropylene composite materials prepared in Examples 1-6 and Comparative Examples 1-8 were used to prepare test specimens using an injection molding machine. Performance tests were performed according to the corresponding national standard test methods. The specific test standards and methods are as follows: Melt mass flow rate MFR: according to GB / T3682.1-2018.

[0056] Tensile yield stress: tested in accordance with GB / T1040-2018 at 23°C, using type 1A specimen, tensile speed 50mm / min, and the testing equipment is the American INSTRON universal material testing machine.

[0057] Simply supported beam notched impact strength: tested at 23°C according to GB / T1043-2008, sample size 80mm×10mm×4mm, notch depth 2mm, testing equipment is impact tester from CEAST, Italy.

[0058] Bending elastic modulus: tested at 23°C according to GB / T9341-2008, sample size 80mm×10mm×4mm, bending speed 2mm / min, span 64mm, testing equipment is universal material testing machine of INSTRON Company, USA.

[0059] Gloss: Tested in accordance with GB / T8807-1988, the sample is a 60mm×60mm×2mm square piece, and the gloss meter produced by BYK is used to test the mirror gloss of the sample at an incident angle of 60°; the downstream product manufacturer is outsourced to prepare corresponding samples of coarse leather grain and fine leather grain, and the gloss of the coarse leather grain and fine leather grain of the sample are tested.

[0060] The crystal structure of the test sample was tested by X-ray diffractometer (wide-angle X-ray diffraction method, WAXD). The sample was a square piece of 60mm×60mm×2mm, and the testing instrument was D / MAX-1200 X-ray diffractometer produced by Rigaku Corporation of Japan.

[0061] Table 3 Properties of polypropylene composites prepared in Examples 1-6 and Comparative Examples 1-8 .

[0062] It can be seen from the data in Table 3 that the specular gloss, coarse grain gloss, and fine grain gloss of the polypropylene composites prepared in Examples 1-6 are all relatively low, among which the specular gloss reaches below 22, the coarse grain gloss reaches below 1.3, and the fine grain gloss reaches below 2.0, which are far lower than the polypropylene composites in the comparative examples. At the same time, the notched impact strength of the polypropylene composites in Examples 1-6 is significantly higher than that in Comparative Examples 1-8, indicating that the polypropylene composites of the present application have lower gloss and excellent rigidity-toughness balance. Therefore, the present application can achieve synergistic synergy by adding metallocene polyethylene, polyolefin elastomer, and dendritic compatibilizer with specific properties to a specific polypropylene resin, significantly reducing the gloss while having excellent rigidity-toughness balance.

[0063] The present invention further analyzes and studies the crystallization behavior of the polypropylene composite material and the PP blank sample prepared in Example 1 and Comparative Example 1 by X-ray diffraction. The specific results are shown in Figure 1 and Table 4.

[0064] Table 4 Calculation results of grain size and peak height ratio of the polypropylene composite materials and PP blank samples prepared in Example 1 and Comparative Example 1 .

[0065] from Figure 1It can be found from Table 4 that after adding specific metallocene polyethylene, polyolefin elastomer and dendritic compatibilizer in Example 1, the peak height ratio of 110 / 040 / 130 crystal plane of polypropylene changes from 1 / 0.75 / 0.52 to 1 / 1.26 / 0.55; at the same time, the grain size is significantly reduced, and the grain size in the normal direction of

[110] ,

[040] and

[130] crystal planes is reduced from 15.4nm, 16.2nm and 9.8nm to 15.0nm, 16.1nm and 8.9nm, and the resulting crystal orientation is conducive to the growth of

[040] crystal plane. It shows that the addition of specific metallocene polyethylene, polyolefin elastomer and dendritic compatibilizer can effectively change the crystallization behavior of polypropylene, and then help to change the gloss effect of the material. However, the polypropylene composite material in Comparative Example 1, the ordinary metallocene polyethylene, polyolefin elastomer and dendritic compatibilizer that exceed the above-mentioned physical property index range have no obvious effect on reducing gloss.

[0066] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A low gloss polypropylene composite material, characterized in that: The composition comprises the following components in parts by weight: Polypropylene resin 53-75 parts; 15-30 parts of inorganic filler; Metallocene polyethylene 5-10 parts; 3-5 parts of polyolefin elastomer; Dendritic compatibilizer 0.8-1.8 parts; Other additives 1-1.5 parts.

2. The low-gloss polypropylene composite material according to claim 1, characterized in that: The polypropylene resin is a copolymer of propylene and ethylene, and has a melt mass flow rate (MFR) of 8-40 g / 10 min under the test conditions of 230° C. and a load of 2.16 kg.

3. The low-gloss polypropylene composite material according to claim 1, characterized in that: The inorganic filler is selected from one or more of silicon dioxide, talc, chopped glass fibers, calcium carbonate, mica or kaolin.

4. The low-gloss polypropylene composite material according to claim 1, characterized in that: The metallocene polyethylene has a melt mass flow rate (MFR) of 0.5-15 g / 10 min under the test conditions of 190° C. and a load of 2.16 kg.

5. The low-gloss polypropylene composite material according to claim 1, characterized in that: The polyolefin elastomer has a melt mass flow rate (MFR) of 0.5-10 g / 10 min under the test conditions of 190° C. and a load of 2.16 kg.

6. The low-gloss polypropylene composite material according to claim 1, characterized in that: The dendritic compatibilizer contains a polyethylene fatty chain with 30-80 carbon atoms and a polar group, wherein the polar group includes one or more of an amide group, a hydroxyl group or a carboxyl group, and the weight average molecular weight of the dendritic compatibilizer is 1500-7500.

7. The low-gloss polypropylene composite material according to claim 1, characterized in that: The other auxiliary agents include one or more of antioxidants, antistatic agents, and masterbatches.

8. A method for preparing the low-gloss polypropylene composite material according to any one of claims 1 to 7, characterized in that: The steps include: (1) Weighing the inorganic filler, metallocene polyethylene, polyolefin elastomer and dendritic compatibilizer in proportion, mixing them evenly, and adding the evenly mixed materials into a twin-screw extruder for melt extrusion and granulation; (2) The polypropylene resin, other additives and the material obtained in step (1) are weighed in proportion and mixed evenly, and the evenly mixed material is added to a twin-screw extruder for melt extrusion and granulation to obtain the low-gloss polypropylene composite material.

9. The method for preparing the low-gloss polypropylene composite material according to claim 8, characterized in that: The method includes one or more of the following features: In step (1), the highest section temperature of the twin-screw extruder is 160-180°C, the main extruder speed is 200-280r / min, and the feed speed is 15-25r / min; In step (2), the highest section temperature of the twin-screw extruder is 160-200°C, the main extruder speed is 230-300r / min, and the feed speed is 20-35r / min.

10. Use of the low-gloss polypropylene composite material according to any one of claims 1 to 7 or the low-gloss polypropylene composite material prepared by the preparation method according to any one of claims 8 to 9 in automotive interior decoration parts and small household appliances.

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