High-gloss high-hardness polypropylene composite material as well as preparation method and application thereof

Abstract

The invention discloses a high-gloss high-hardness polypropylene composite material as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The high-gloss high-hardness polypropylene composite material is prepared from the following components in parts by weight: 44 to 70 parts of homo-polypropylene resin, 5 to 10 parts of high-density polyethylene, 5 to 10 parts of linear low-density polyethylene, 5 to 10 parts of SEBS elastomer, 10 to 25 parts of filler and 0.2 to 0.6 part of antioxidant, and the filler is inorganic flaky filler. By compounding the high-density polyethylene, the linear low-density polyethylene, the SEBS elastomer, the filler and the homo-polypropylene resin of which the crystallinity is not less than 45%, the hardness of the polypropylene composite material can be ensured, and meanwhile, the glossiness of the polypropylene composite material is effectively improved, so that the polypropylene composite material can meet the application requirements for preparing plastic products.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to a high-gloss and high-hardness polypropylene composite material, a preparation method thereof, and an application thereof. Background Art

[0002] Compared with other general thermoplastic resins, polypropylene resin is often used for automotive decorative parts because of its advantages such as low density, low price, and good processing performance. However, compared with other resins (such as ABS, HIPS, etc.), the glossiness of polypropylene is significantly lower, and this defect significantly limits the application of polypropylene resin materials in automotive decorative parts with higher glossiness requirements.

[0003] In addition, the hardness of polypropylene resin itself is not high, and its injection-molded products are easily scratched, scraped, or worn during use. At present, the hardness of polypropylene materials is mostly improved by adding inorganic fillers, but the compatibility between the fillers and polypropylene resin is poor, which may cause surface defects and affect the glossiness of the materials.

[0004] Therefore, it is urgent to develop a high-gloss and high-hardness polypropylene composite material. Summary of the Invention

[0005] Based on the defects existing in the prior art, the purpose of the present invention is to provide a high-gloss and high-hardness polypropylene composite material, a preparation method thereof, and an application thereof.

[0006] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] In the first aspect, a high-gloss and high-hardness polypropylene composite material provided by the present invention comprises the following components in parts by weight: 44-70 parts of homopolypropylene resin, 5-10 parts of high-density polyethylene, 5-10 parts of linear low-density polyethylene, 5-10 parts of SEBS elastomer, 10-25 parts of filler, and 0.2-0.6 part of antioxidant. The crystallinity of the homopolypropylene resin is not less than 45%, the filler is an inorganic flaky filler, the melt flow rate of the SEBS elastomer at 200°C and 5 kg load is not more than 5.5 g / 10 min, and the melt flow rate of the high-density polyethylene at 190°C and 2.16 kg load is not more than 3 g / 10 min.

[0008] By compounding high-density polyethylene, linear low-density polyethylene, SEBS elastomer, filler, and homopolypropylene resin, the present invention can ensure the hardness of the polypropylene composite material and effectively improve the glossiness of the polypropylene composite material, so that the polypropylene composite material can meet the application requirements for preparing plastic products.

[0009] In the present invention, the sum of the weight percentages of the homopolypropylene resin, high-density polyethylene, and linear low-density polyethylene in the polypropylene composite material is not less than 65%.

[0010] In the present invention, the crystallinity of the homopolypropylene resin may be 45%, 48%, 50%, 55%, 60%, 65%, 66%, 70%, or a range composed of any two sets of these values.

[0011] Preferably, the crystallinity of the homopolypropylene resin is 48-70%.

[0012] Preferably, the melt flow rate of the homopolypropylene resin at 230°C and a load of 2.16 Kg is 12-20 g / 10 min.

[0013] Preferably, the melt flow rate of the high-density polyethylene at 190°C and a load of 2.16 kg is 0.5-3 g / 10 min.

[0014] In the present invention, the melt flow rate of the high-density polyethylene at 190°C and a load of 2.16 kg may be 0.5 g / 10 min, 1 g / 10 min, 1.5 g / 10 min, 2 g / 10 min, 2.5 g / 10 min, 3 g / 10 min, or a range composed of any two sets of these values.

[0015] More preferably, the melt flow rate of the high-density polyethylene at 190°C and a load of 2.16 kg is 1-3 g / 10 min.

[0016] The inventors have found through research that if the melt flow rate of the high-density polyethylene is within a suitable range, the high-density polyethylene is more likely to migrate to the surface of the polypropylene composite material during the injection molding process to form crystals, thereby improving the gloss of the polypropylene composite material.

[0017] Preferably, the melt flow rate of the linear low-density polyethylene at 190°C and a load of 2.16 kg is 1-3 g / 10 min.

[0018] In the present invention, the melt flow rate of the linear low-density polyethylene at 190°C and a load of 2.16 kg may be 1 g / 10 min, 1.5 g / 10 min, 2 g / 10 min, 2.5 g / 10 min, 3 g / 10 min, or a range composed of any two sets of these values.

[0019] The inventors have found through research that by introducing a linear low-density polyethylene with a suitable melt flow rate in the present invention, the gloss of the polypropylene composite material can be significantly improved, and the overall toughness of the polypropylene composite material can also be improved to a certain extent.

[0020] Preferably, the melt flow rate of the SEBS elastomer at 200 °C and a load of 5 kg is 1 to 5.5 g / 10 min. The melt flow rate of the SEBS elastomer at 200 °C and a load of 5 kg can be 1 g / 10 min, 1.5 g / 10 min, 2 g / 10 min, 2.5 g / 10 min, 3 g / 10 min, 3.1 g / 10 min, 3.5 g / 10 min, 4 g / 10 min, 4.5 g / 10 min, 5 g / 10 min, 5.5 g / 10 min or the range composed of any two sets of these values.

[0021] More preferably, the melt flow rate of the SEBS elastomer at 200 °C and a load of 5 kg is 3.1 to 5.5 g / 10 min.

[0022] The inventors have found through research that the SEBS elastomer with an appropriate melt flow rate has good compatibility with the homopolypropylene resin. During the injection molding process, the SEBS elastomer easily migrates to the surface of the polypropylene composite material and has a good stretching effect, thereby promoting the highly directional arrangement of the flaky inorganic filler on the surface of the plastic product to form a mirror effect, and thus greatly improving the gloss of the plastic product.

[0023] Preferably, the filler is mica, and the mesh number of the filler is 400 to 800 mesh. The mesh number of the filler can be 400 mesh, 500 mesh, 600 mesh, 700 mesh, 800 mesh or the range composed of any two sets of these values.

[0024] Preferably, the high-gloss and high-hardness polypropylene composite material comprises the following components in parts by weight: 50 to 60 parts of homopolypropylene resin, 6 to 8 parts of high-density polyethylene, 6 to 8 parts of linear low-density polyethylene, 6 to 8 parts of SEBS elastomer, 15 to 20 parts of filler, and 0.3 to 0.4 part of antioxidant.

[0025] Preferably, the antioxidant comprises at least one of a hindered phenol antioxidant and a phosphite antioxidant.

[0026] In a second aspect, a method for preparing the high-gloss and high-hardness polypropylene composite material as described in the first aspect of the present invention includes the following steps:

[0027] Mix the components and then perform melt blending extrusion, granulation, and drying to obtain the polypropylene composite material.

[0028] Preferably, the temperature of the melt blending extrusion is 220 to 235 °C, and the screw speed is 150 to 200 rpm.

[0029] In a third aspect, an application of the high-gloss and high-hardness polypropylene composite material as described in the first aspect of the present invention in the preparation of plastic products.

[0030] The plastic product can be an interior automotive part or an exterior automotive part.

[0031] In a fourth aspect, a plastic product made of the high-gloss and high-hardness polypropylene composite material described in the first aspect of the present invention is provided.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] By compounding high-density polyethylene, linear low-density polyethylene, SEBS elastomer, filler and homopolypropylene resin, the present invention can ensure the hardness of the polypropylene composite material, and at the same time effectively improve the gloss of the polypropylene composite material, so that the polypropylene composite material can meet the application requirements for preparing plastic products. Specific Embodiments

[0034] In order 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 and comparative examples. The purpose is to understand the content of the present invention in detail, rather than to limit the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0035] In the present invention, the test method for the melt mass flow rate of the homopolypropylene resin is the method specified in Standard ISO1133-2011, the test temperature is 230°C, and the load is 2.16 Kg.

[0036] The test method for the crystallinity of the homopolypropylene resin is differential scanning calorimetry. The test temperature ranges from room temperature to 230°C, and the heating rate is 10°C / min. The melting enthalpy △H is obtained according to the DSC curve, and the crystallinity = △H1 / △H2 * 100%, where △H2 is the melting heat of 100% crystallization of the sample (the melting heat of 100% crystallization of homopolypropylene is 209 J / g).

[0037] The test method for the melt flow rate of the high-density polyethylene is the method specified in Standard ISO1133-2011, the test temperature is 190°C, and the load is 2.16 Kg.

[0038] The test method for the melt flow rate of the linear low-density polyethylene is the method specified in Standard ISO1133-2011, the test temperature is 190°C, and the load is 2.16 Kg.

[0039] The test method for the melt flow rate of the SEBS elastomer is the method specified in Standard ISO1133-2011, the test temperature is 200°C, and the load is 5 Kg.

[0040] The source information and performance parameters of the components in each example and comparative example are shown in Table 1 below.

[0041] Table 1

[0042]

[0043]

[0044] Unless otherwise specified, the component raw materials used in each example and comparative example of the present invention are all commercially available raw materials, and the component raw materials used in each parallel experiment are of the same kind.

[0045] Examples 1 to 14

[0046] Examples of the high-gloss and high-hardness polypropylene composite material of the present invention, the components and their weight ratios of the high-gloss and high-hardness polypropylene composite material are shown in Tables 2 to 3.

[0047] The preparation method of the high-gloss and high-hardness polypropylene composite material includes the following steps:

[0048] After mixing the components, melt-blend and extrude through a twin-screw extruder, pelletize, and dry to obtain the high-gloss and high-hardness polypropylene composite material. The temperatures of each zone of the twin-screw extruder from the feeding section to the die head are as follows: Zone 1: 220 °C, Zone 2: 235 °C, Zone 3: 235 °C, Zone 4: 235 °C, Zone 5: 235 °C, Zone 6: 235 °C, Zone 7: 230 °C, Zone 8: 230 °C, Zone 9: 225 °C, Zone 10: 225 °C. The screw speed of the twin-screw extruder is 180 rpm, and the length-diameter ratio of the screw is 40:1.

[0049] Table 2 (unit: parts by weight)

[0050]

[0051]

[0052] Table 3 (unit: parts by weight)

[0053]

[0054] Comparative Examples 1 to 8

[0055] The difference between each comparative example and the example lies only in the types and ratios of the components, as shown in Table 4.

[0056] Table 4 (unit: parts by weight)

[0057]

[0058] To verify the performance of the composite materials of the present invention, the composite materials prepared in each of the examples and comparative examples were used as samples for the following performance tests:

[0059] (1) Surface glossiness: The samples were injection-molded and cut into specimens with dimensions of 3 mm (thickness) × 100 mm × 100 mm, and tested using a glossiness tester according to the standard ASTM D523-2014, with a test angle of 60°;

[0060] (2) Rockwell hardness (HCR): Tested according to the standard GB / T3398.2-2008.

[0061] The test results are shown in Tables 5 to 6.

[0062] Table 5

[0063]

[0064] Table 6

[0065]

[0066]

[0067] In each of the examples of the present invention, through the compounding of high-density polyethylene, linear low-density polyethylene, SEBS elastomer, filler and homopolypropylene resin, the hardness of the polypropylene composite material can be ensured, and at the same time, the glossiness of the polypropylene composite material can be effectively improved, with the glossiness not less than 74 and the hardness not less than 77.

[0068] It can be seen from Examples 1, 5 to 6 and Comparative Example 1 that the crystallinity of the homopolypropylene resin is not less than 45%, which can improve the overall crystallinity of the polypropylene composite material, and thus improve the glossiness of the injection-molded product, and can also improve the hardness of the polypropylene composite material to a certain extent.

[0069] It can be seen from Examples 1, 7 to 8 and Comparative Example 2 that high-density polyethylene with a melt flow rate not greater than 3 g / 10 min is more likely to migrate to the surface of the polypropylene composite material to form crystals during the injection molding process, which can improve the glossiness of the injection-molded product while ensuring the hardness of the injection-molded product.

[0070] It can be seen from Examples 1, 9 to 10 and Comparative Examples 3 to 5 that by controlling the addition amount of linear low-density polyethylene within an appropriate range, the glossiness of the polypropylene composite material can be significantly improved while ensuring the hardness of the polypropylene composite material.

[0071] As can be seen from Example 1, Examples 11 to 12 and Comparative Example 6, the melt mass flow plastics with SEBS elastomers within an appropriate range have good stretching effects during the injection molding process, can better drive the orientation of fillers, and thus can significantly improve the gloss of injection molded products while ensuring the hardness of polypropylene composites.

[0072] As can be seen from Example 1, Examples 13 to 14 and Comparative Examples 7 to 8, controlling the particle size of inorganic flaky fillers within an appropriate range can improve the hardness and gloss of polypropylene composites.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A high-gloss and high-hardness polypropylene composite material, characterized in that, It comprises the following components in parts by weight: 44 - 70 parts of homopolypropylene resin, 5 - 10 parts of high-density polyethylene, 5 - 10 parts of linear low-density polyethylene, 5 - 10 parts of SEBS elastomer, 10 - 25 parts of filler, 0.2 - 0.6 part of antioxidant. The crystallinity of the homopolypropylene resin is not less than 45%. The filler is an inorganic flaky filler. The melt flow rate of the SEBS elastomer at 200°C and 5 kg load is not more than 5.5 g / 10 min, and the melt flow rate of the high-density polyethylene at 190°C and 2.16 kg load is not more than 3 g / 10 min.

2. The high-gloss and high-hardness polypropylene composite material according to claim 1, characterized in that, The crystallinity of the homopolypropylene resin is 48 - 70%.

3. The high-gloss and high-hardness polypropylene composite material according to claim 1, wherein The melt flow rate of the high-density polyethylene at 190°C and 2.16 kg load is 0.5 - 3 g / 10 min, and more preferably 1 - 3 g / 10 min.

4. The high-gloss and high-hardness polypropylene composite material according to claim 1, wherein The melt flow rate of the linear low-density polyethylene at 190°C and 2.16 kg load is 1 - 3 g / 10 min.

5. The high-gloss and high-hardness polypropylene composite material according to claim 1, wherein The melt flow rate of the SEBS elastomer at 200°C and 5 kg load is 1 - 5.5 g / 10 min, and more preferably 3.1 - 5.5 g / 10 min.

6. The high-gloss and high-hardness polypropylene composite material according to claim 1, wherein, The filler is an inorganic flaky filler, and the mesh number of the filler is 400 - 800 mesh.

7. The high-gloss and high-hardness polypropylene composite material according to claim 1, characterized in that, It comprises the following components in parts by weight: 50 - 60 parts of homopolypropylene resin, 6 - 8 parts of high-density polyethylene, 6 - 8 parts of linear low-density polyethylene, 6 - 8 parts of SEBS elastomer, 15 - 20 parts of filler, 0.3 - 0.4 part of antioxidant.

8. A method for preparing a high-gloss and high-hardness polypropylene composite material according to any one of claims 1 to 7, characterized in that, It comprises the following steps: Mix the components and then carry out melt blending extrusion, granulation, and drying to obtain the polypropylene composite material.

9. Use of the high-gloss and high-hardness polypropylene composite material according to any one of claims 1 - 7 in the preparation of plastic products.

10. A plastic product made from the high-gloss and high-hardness polypropylene composite material according to any one of claims 1 - 7.

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