Polypropylene composition, and preparation method therefor and use thereof

Abstract

The present invention relates to the technical field of polymer materials, and disclosed are a polypropylene composition, and a preparation method therefor and a use thereof. In the product, a styrene-ethylene-butylene-styrene block copolymer is introduced into a polypropylene resin matrix for compounding to form a resin system, and a silicate-based filler having a specific whiteness and a sorbitol-based light transmittance improver are selected for compounding. Under the synergistic action of the components, the product not only can achieve high light transmittance, but also has high surface energy and ideal paint adhesion.

Description

A polypropylene composition, its preparation method and application Technical Field

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

[0002] Polypropylene is widely used in the automotive, electronics, and home appliance industries due to its ideal mechanical and processing properties. However, when polypropylene is used in the automotive sector, especially in the manufacture of automotive exterior parts, certain parts require high light transmittance to meet usage standards. Therefore, anti-reflective agents are typically introduced to improve the transparency of these products. However, using small amounts of these anti-reflective agents is currently insufficient to meet usage requirements, while large-scale introduction of anti-reflective agents, besides increasing production costs, may also weaken other product properties.

[0003] On the other hand, automotive exterior parts made of polypropylene generally require painting, thus necessitating a certain surface energy in the material to ensure physical adhesion between the paint layer and the material. However, existing high-transmittance polypropylene materials, due to the selection of fillers and additives, struggle to achieve ideal paint adhesion. Summary of the Invention

[0004] Based on the deficiencies of existing technologies, the present invention aims to provide a polypropylene composition. This product is formed by compounding styrene-ethylene-butene-styrene block copolymer (SEBS) into a polypropylene resin matrix to form a resin system. At the same time, silicate fillers with specific whiteness and sorbitol-based brighteners are selected for compounding. Under the synergistic effect of each component, the product can not only achieve high light transmittance, but also has high surface energy and ideal paint adhesion.

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

[0006] A polypropylene composition comprising the following components in parts by weight:

[0007] 45-80 parts polypropylene resin, 10-40 parts SEBS, 5-35 parts silicate filler, and 0.1-0.5 parts clarity enhancer;

[0008] The whiteness of the silicate filler is ≥94%;

[0009] The penetration enhancer is a sorbitol-based penetration enhancer.

[0010] Preferably, the whiteness of the silicate filler is tested directly using a whiteness meter.

[0011] The specific test method for the whiteness of the silicate filler is as follows: Using a WGB-2A benchtop whiteness meter manufactured by Shanghai Precision Instruments Co., Ltd., place the light-shielding black tube on the measuring hole beforehand, zero the instrument with the zero-adjustment potentiometer, and remove the black tube after the instrument is at zero. Place a standard whiteness plate on the plate and adjust the standard whiteness value with the instrument calibration potentiometer to calibrate the instrument. Then remove the standard whiteness plate. Measure the sample to be tested to determine the whiteness value.

[0012] SEBS, due to its good elasticity, is often used as a toughening agent in plastic products. In the technical solution of this invention, introducing SEBS as a synergistic component into the polypropylene resin matrix not only improves the product's light transmittance but also gives it high surface energy, resulting in strong adhesion during painting. On the other hand, since the surface energy of a product is related to its roughness, and product roughness is greatly influenced by the amount of filler introduced, insufficient filler can hinder the achievement of adequate surface energy. However, excessive filler or unsuitable filler types can negatively impact light transmittance. Therefore, in this invention, high-whiteness silicate fillers and sorbitol-based brighteners are further introduced into the polypropylene + SEBS composite resin matrix. The combined effect of these two components ensures high light transmittance; simultaneously, the polar functional groups on the filler surface optimize its dispersion uniformity in the resin matrix, ensuring sufficient surface energy for the product. If other types of fillers are chosen, such as the commonly used titanium-based fillers, even with high whiteness, the product will still struggle to achieve the desired surface energy due to their low light transmittance. Furthermore, while using silicate fillers with insufficient whiteness can ensure surface energy, the product's light transmittance is not ideal. Similarly, other types of antireflective agents cannot function effectively in this system, failing to balance light transmittance and surface energy.

[0013] Preferably, the polypropylene composition comprises the following components in parts by weight:

[0014] 55-75 parts polypropylene resin, 15-35 parts SEBS, 10-30 parts silicate filler, and 0.1-0.5 parts clarity enhancer.

[0015] More preferably, the mass ratio of the polypropylene resin to SEBS is (60-70):(20-30).

[0016] When the polypropylene resin and SEBS are used in the above-mentioned preferred mass ratio, the polypropylene resin matrix can improve the dispersion and function of fillers and brighteners, resulting in better light transmittance and surface energy of the product.

[0017] Preferably, the polypropylene resin has a mass content of ≥45wt% in the polypropylene composition.

[0018] More preferably, the ratio of the total mass of the polypropylene resin and SEBS to the mass of the silicate filler is (9:1) to (7:3).

[0019] Preferably, the polypropylene resin has a melt flow rate of 1 to 100 g / 10 min at 230°C and 2.16 kg load, according to ISO 1133-2011 standard.

[0020] More preferably, the melt flow rate of the polypropylene resin at 230°C and 2.16 kg load is 30-60 g / 10 min.

[0021] Preferably, the weight-average molecular weight of the SEBS is 20,000 to 120,000 g / mol;

[0022] The weight-average molecular weight of the SEBS was determined by gel permeation chromatography.

[0023] The specific method for testing the weight-average molecular weight of SEBS is as follows: An appropriate amount of SEBS is dissolved in tetrahydrofuran. The resulting SEBS solution is filtered through a 0.22 μm pore size filter membrane and then subjected to weight-average molecular weight testing using a Viscotek TDA302 gel permeation chromatograph. The detector used is a differential and laser scattering detector. The eluent is tetrahydrofuran, the flow rate is 1.0 mL / min, the test temperature is 25 °C, the mass concentration of the SEBS solution during testing is 2–5 g / L, and the standard is polystyrene.

[0024] More preferably, the weight-average molecular weight of the SEBS is 30,000 to 75,000 g / mol.

[0025] More preferably, the weight-average molecular weight of the SEBS is 35,000 to 50,000 g / mol.

[0026] SEBS and polypropylene resin have different polymer particle sizes, therefore homogeneous compatibility does not occur during the bonding process. Furthermore, the weight-average molecular weight of SEBS alters its dispersibility within the polypropylene resin and its traction effect on the filler. The inventors discovered that by selecting SEBS with the aforementioned weight-average molecular weight, the prepared product can achieve higher light transmittance while maintaining surface energy.

[0027] Preferably, the SEBS melt flow rate at 230°C and 2.16 kg load, according to ISO 1133-2011 standard, is 1-15 g / 10 min.

[0028] Preferably, the silicate filler includes at least one of silicate and aluminosilicate;

[0029] More preferably, the silicate filler is at least one of talc powder, glass fiber powder, mica powder, and quartz powder.

[0030] More preferably, the average particle size of the mica powder and / or talc powder and / or quartz powder is 8 to 16 μm.

[0031] More preferably, the glass fiber powder has an average diameter of 10-13 μm and an average length of 20-50 μm.

[0032] The average particle size of mica powder and / or talc powder and / or quartz powder in the silicate filler of the present invention was confirmed by laser particle size analyzer using the laser diffraction method according to the Chinese national standard GB / T 19077-2016.

[0033] The average length and average diameter of the glass fiber powder in the silicate filler of the present invention were confirmed by the following method: the glass fiber powder was dispersed in water, treated with ultrasonic oscillation, and then statistically confirmed using a two-dimensional measuring instrument.

[0034] Preferably, in the polypropylene composition, the retained average particle size of the silicate filler is 4–15 μm.

[0035] The average retained particle size of silicate fillers in the polypropylene composition of the present invention refers to the average particle size retained by silicate fillers in the product after the polypropylene composition is melt-extruded and granulated.

[0036] Preferably, in the polypropylene composition, the retained average particle size of mica powder and / or talc powder and / or quartz powder is 4 to 10 μm.

[0037] Preferably, in the polypropylene composition, the average retained particle size of the glass fiber powder is 10-15 μm.

[0038] The test method for the retained average particle size of the silicate filler of the present invention is as follows: calcining the polypropylene composition at 800°C for 30 min in an air atmosphere, sieving the ash content, and then confirming it by laser particle size analyzer according to the Chinese national standard GB / T19077-2016 Particle Size Distribution Laser Diffraction Method.

[0039] Preferably, the mass ratio of the silicate filler to the penetration enhancer is 1:(0.015~0.04).

[0040] As mentioned above, silicate fillers and antireflective agents exhibit a synergistic effect when used in combination. On one hand, silicate fillers impart sufficient surface energy to the product; on the other hand, the combined action of silicate fillers and antireflective agents allows the product to maintain high light transmittance regardless of the filler content. Furthermore, when the mass ratio of silicate filler to antireflective agent is within the aforementioned range, the product achieves even higher light transmittance and maintains a surface energy above 24 dyne.

[0041] Preferably, the sorbitol-based penetrant is at least one of 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propenyl)methylene]-nonanol, 1,3:2,4-bis(3,4-dimethylbenzyl)-D-sorbitol, diphenylmethylene sorbitol, and di(p-methyldiphenylmethylene)sorbitol.

[0042] Preferably, the polypropylene composition further includes 0.1 to 1 part of an antioxidant and 0.1 to 1 part of a light stabilizer.

[0043] More preferably, the antioxidant is at least one of hindered phenolic antioxidants, phosphite antioxidants, and thioester antioxidants.

[0044] More preferably, the antioxidant is a mixture of hindered phenolic antioxidants and phosphite antioxidants, with a mass ratio of (0.8-1.2):(0.8-1.2).

[0045] More preferably, the light stabilizer is a hindered amine light stabilizer.

[0046] Preferably, the polypropylene composition further includes 0.1 to 3 parts of processing aids.

[0047] More preferably, the processing aid includes at least one of an antistatic agent, a lubricant, an antibacterial agent, and a colorant.

[0048] It should be noted that the polypropylene composition described in this invention may include, but is not limited to, the processing aids mentioned above, depending on actual needs. Without affecting the light transmittance and surface energy effects of the polypropylene composition, those skilled in the art can select various processing aids to impart other performance effects to the product. For example, to impart antistatic properties to the product and thus achieve safety in the automotive field, an appropriate amount of antistatic agent can be added to the product; and to increase the processing efficiency and demolding effect of the product, a suitable lubricant can be introduced into the product, etc.

[0049] Another object of the present invention is to provide a method for preparing the polypropylene composition, comprising the following steps:

[0050] The components are mixed evenly, and then melt-extruded and granulated in a screw extruder to obtain the polypropylene composition.

[0051] Preferably, during melt extrusion of the components, the temperature zones of the screw extruder are set as follows: Zone 1: 170–190℃, Zone 2: 170–190℃, Zone 3: 190–210℃, Zone 4: 190–210℃, Zone 5: 190–210℃, Zone 6: 200–220℃, Zone 7: 200–220℃, Zone 8: 200–220℃, Zone 9: 200–220℃, Zone 10: 200–220℃, the screw speed is 350–450 rpm, and the screw length-to-diameter ratio is (40–50):1.

[0052] The preparation method of the polypropylene composition of the present invention is simple to operate, requires little equipment, and can achieve industrial-scale production.

[0053] Another object of the present invention is to provide the use of the polypropylene composition in the preparation of automotive trim parts.

[0054] Preferably, the automotive decorative components include at least one of the following: an integrated illuminated front fascia, an illuminated tailgate back panel, an illuminated door panel, an illuminated fender, an illuminated trim strip, and an intelligent control panel.

[0055] Another object of the present invention is to provide an automotive trim component comprising the polypropylene composition described herein.

[0056] The polypropylene composition of the present invention has ideal light transmission effect and can achieve a large surface energy in water and solvents, and can achieve high adhesion to water-based coatings and paints. Therefore, it is very suitable for the above-mentioned automotive decorative parts that have high requirements for light transmission and paint film adhesion.

[0057] The beneficial effects of the present invention are that it provides a polypropylene composition, which is formed by introducing SEBS into a polypropylene resin matrix to form a resin system, and by selecting silicate fillers with specific whiteness and sorbitol-based brighteners for compounding. Under the synergistic effect of the components, the product can not only achieve high light transmittance, but also has high surface energy and ideal paint adhesion. Detailed Implementation

[0058] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments and comparative examples. The purpose of this description is to provide a detailed understanding of the invention, not to limit its scope. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this invention. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this invention are commonly used reagents and instruments.

[0059] Examples 1-20

[0060] An embodiment of the polypropylene composition, its preparation method and application described in this invention, wherein the composition of the polypropylene composition is shown in Table 1.

[0061] The method for preparing the polypropylene composition includes the following steps:

[0062] The components are mixed evenly, and then melt-extruded and granulated in a screw extruder to obtain the polypropylene composition.

[0063] During melt extrusion of the components, the temperature zones of the screw extruder are set as follows: Zone 1: 180℃, Zone 2: 180℃, Zone 3: 200℃, Zone 4: 200℃, Zone 5: 200℃, Zone 6: 210℃, Zone 7: 210℃, Zone 8: 210℃, Zone 9: 210℃, Zone 10: 210℃. The screw speed is 400 rpm, and the screw length-to-diameter ratio is 48:1.

[0064] Comparative Examples 1-10

[0065] The only difference between each comparative example and the embodiment is the type and ratio of components, as shown in Table 2.

[0066] In the components described in each embodiment and comparative example,

[0067] The polypropylene resin 1 is PPH9018 produced by China Petroleum & Chemical Corporation, and its melt flow rate is 60 g / 10 min at 230°C and 2.16 kg load.

[0068] The polypropylene resin 2 is PP 320 powder produced by Maoming Petrochemical Co., Ltd. of China Petroleum & Chemical Corporation, with a melt flow rate of 32 g / 10 min at 230℃ and 2.16 kg load.

[0069] The styrene-ethylene-butene-styrene block copolymer 1 (SEBS1) is SEBS1643 produced by Kraton Pharmaceuticals, Inc., with a weight-average molecular weight of 40,000 g / mol.

[0070] The styrene-ethylene-butene-styrene block copolymer 2 (SEBS2) is SEBS1652 produced by Kraton Pharmaceuticals, Inc., with a weight-average molecular weight of 35,000 g / mol.

[0071] The styrene-ethylene-butene-styrene block copolymer 3 (SEBS 3) is SEBS1657 produced by Kraton Pharmaceuticals, Inc., with a weight-average molecular weight of 50,000 g / mol.

[0072] The styrene-ethylene-butene-styrene block copolymer 4 (SEBS 4) is SEBS1651 produced by Kraton Pharmaceuticals, Inc., with a weight-average molecular weight of 110,000 g / mol.

[0073] The styrene-ethylene-butene-styrene block copolymer 5 (SEBS 5) is SEBS1726 produced by Kraton Pharmaceuticals, Inc., with a weight-average molecular weight of 30,000 g / mol.

[0074] The styrene-butadiene-styrene copolymer (SBS) is SBS1153 produced by Kraton Pharmaceuticals, Inc., with a weight-average molecular weight of 40,000 g / mol.

[0075] The acrylonitrile-butadiene-styrene copolymer (ABS) is ABS KF730 produced by China Kingfa Science & Technology Co., Ltd., with a weight-average molecular weight of 55,000 g / mol;

[0076] The styrene-butadiene copolymer (SBR) is SBR1605 produced by Dow Chemical Company, USA, with a weight-average molecular weight of 55,000 g / mol;

[0077] The glass fiber powder is MF7904 produced by China Taishan Glass Fiber Co., Ltd., with an average diameter of 12μm, an average length of 25μm, and a whiteness of 94%.

[0078] The mica powder is W-600 produced by Huajing Mica Co., Ltd. in Lingshou County, China. After screening, the average particle size is 15μm and the whiteness is 94%.

[0079] The quartz powder is produced by Wuhan Jiyesheng Chemical Co., Ltd. in China. After screening, the average particle size is 10μm and the whiteness is 94%.

[0080] The talc powder 1 is BHS1851 produced by Quanzhou Xufeng Powder Raw Material Co., Ltd. in China. After screening, the average particle size is 12μm and the whiteness is 94%.

[0081] The talc powder 2 is 1250 talc powder produced by Lingshou County Chengnuo Mineral Products Co., Ltd. in China. After screening, the average particle size is 10μm and the whiteness is 90%.

[0082] The montmorillonite mentioned was 1.3PS produced by NANOCOR Corporation of the United States, with an average particle size of 10 μm and a whiteness of 85%.

[0083] The titanium dioxide is TS1511 produced by Chemours, Inc. of the United States, with a whiteness of 95%.

[0084] The solubilizer 1 is NX8000K, a sorbitol-based solubilizer manufactured by Milliken Laboratories, Inc., USA, specifically 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propenyl)methylene]-nonanol.

[0085] The solubilizer 2 is Millad 3988, a sorbitol-based solubilizer, manufactured by Milliken Laboratories, USA, specifically 1,3:2,4-di(3,4-dimethylbenzylene)-D-sorbitol.

[0086] The brightening agent 3 is NA-21, a metal phosphate, manufactured by Idico Corporation of Japan.

[0087] The penetrating agent 4 is sodium benzoate produced by Shanxi Provincial Chemical Research Institute;

[0088] The antioxidant is a mixture of commercially available hindered phenolic antioxidants and phosphite antioxidants in a mass ratio of 1:1;

[0089] The light stabilizer is a commercially available hindered amine light stabilizer.

[0090] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this invention are commercially available, and the same type of components and raw materials are used in each parallel experiment.

[0091] The test method for the retention average particle size of the filler in each product in the embodiments and comparative examples is as follows: each product is calcined in air at 800°C for 30 minutes, and then the ash content is sieved and confirmed by laser particle size analyzer according to the Chinese national standard GB / T19077-2016 Particle Size Distribution Laser Diffraction Method.

[0092] Table 1

[0093] Table 2

[0094] To verify the performance of the polypropylene composition described in this invention, the products prepared in each embodiment and comparative example were subjected to the following performance tests, with the specific steps as follows:

[0095] (1) Light transmittance test: Each product was injection molded into a test square plate of 100×100×3mm, and then tested according to Chinese national standard GB 2410-2008;

[0096] (2) Surface energy test: Water and α-bromonaphthalene were dropped onto the surface of the test plate prepared in step (1) respectively, the liquid contact angle was tested, and then the surface energy of the product was tested by the Owens two-liquid method.

[0097] The test results are shown in Tables 3 and 4.

[0098] Table 3

[0099] Table 4

[0100] As shown in Tables 3 and 4, the polypropylene composition of this invention exhibits excellent performance, with a light transmittance of 60% or higher and a surface energy of at least 24 dyne, providing ideal paint adhesion and making it highly suitable for automotive decorative parts. Examples 1 and 4-7 demonstrate that the proportion of SEBS in the polypropylene resin matrix affects the product's dispersion and light transmittance. As the SEBS content increases, the light transmittance increases, while the surface energy fluctuates. When the ratio of polypropylene resin to SEBS is (60-70):(20-30), the product achieves a balance between optimal light transmittance and surface energy. On the other hand, Examples 1 and 9-12 show that, possibly due to the different particle sizes and molecular chains of SEBS and polypropylene resin, as the molecular weight of SEBS increases, the dispersibility of SEBS in the polypropylene resin and its traction effect on fillers also change. Consequently, the overall light transmittance of the product varies, and within a certain range, the surface adhesion of the product also changes. When the weight-average molecular weight of SEBS is 30,000–75,000 g / mol, the product can achieve higher light transmittance.

[0101] In contrast, in Comparative Examples 1-3, although the surface energy of the products was high, the transmittance could not reach over 60% because the polypropylene resin was not paired with SEBS. As can be seen from the products described in Comparative Examples 4-6 and Examples 1 and 13-15, the choice of filler cannot be arbitrary in order to achieve high transmittance and high surface energy. Besides requiring specific silicate fillers, high whiteness is also essential; otherwise, the product cannot achieve the expected performance. As can be seen from Comparative Examples 7-9, the use of a light-reflecting agent is also a key factor in the products of this invention. Different types of light-reflecting agents will result in different light-reflecting effects, but if the type of light-reflecting agent is unsuitable, even increasing its amount will have a very limited effect on improving the transmittance. Furthermore, the compatibility and compounding of the light-reflecting agent with the resin matrix and filler will also affect the dispersibility of the filler, thus affecting the surface roughness of the product. In addition, if a type of light-reflecting agent not specified in this invention is chosen, it may weaken the surface energy of the product.

[0102] As can be seen from Examples 1 and 17-20 and Comparative Example 10, in the product of the present invention, when the filler ratio is fixed, the amount of anti-reflective agent added affects the surface energy of the product. The main reason is that the two actually produce a synergistic effect. When the amount of anti-reflective agent added is within a suitable range, the use of anti-reflective agent can ensure the uniform dispersion of the filler while maintaining the product's light transmittance, thereby giving the product surface sufficient roughness. However, if too much anti-reflective agent is added, the product's light transmittance will not increase further; instead, it will reduce the uniformity of filler dispersion and weaken the product's surface energy. Therefore, it is necessary to limit the amount of anti-reflective agent added to a specific range, and when the mass ratio of silicate filler to anti-reflective agent is in the range of 1:(0.015-0.04), the surface energy of the product can be maintained at a higher level.

[0103] 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 polypropylene composition, characterized in that, Includes the following components in parts by weight: The composition includes 45-80 parts of polypropylene resin, 10-40 parts of styrene-ethylene-butene-styrene block copolymer (SEBS), 5-35 parts of silicate filler, and 0.1-0.5 parts of a brightening agent; the silicate filler has a whiteness ≥94%. The penetration enhancer is a sorbitol-based penetration enhancer.

2. The polypropylene composition according to claim 1, characterized in that, The weight-average molecular weight of the SEBS is 20,000 to 120,000 g / mol.

3. The polypropylene composition according to claim 1 or 2, characterized in that, The silicate filler includes at least one of silicate and aluminosilicate.

4. The polypropylene composition according to claim 3, characterized in that, The silicate filler is at least one of talc powder, glass fiber powder, mica powder, and quartz powder.

5. The polypropylene composition according to claim 4, characterized in that, The average particle size of the mica powder and / or talc powder and / or quartz powder is 8-16 μm; and / or the average diameter of the glass fiber powder is 10-13 μm and the average length is 20-50 μm.

6. The polypropylene composition according to any one of claims 1-5, characterized in that, The mass ratio of the polypropylene resin to SEBS is (60-70):(20-30); the mass ratio of the total mass of the polypropylene resin and SEBS to the mass of the silicate filler is (9:1) to (7:3).

7. The polypropylene composition according to any one of claims 1-6, characterized in that, The mass ratio of the silicate filler to the penetration enhancer is 1:(0.015~0.04).

8. The polypropylene composition according to any one of claims 1-7, characterized in that, The polypropylene composition further includes 0.1 to 1 part of an antioxidant and 0.1 to 1 part of a light stabilizer; the antioxidant is at least one of hindered phenolic antioxidants, phosphite antioxidants, and thioester antioxidants; the light stabilizer is a hindered amine light stabilizer.

9. The method for preparing the polypropylene composition according to any one of claims 1 to 8, characterized in that, Includes the following steps: The components are mixed evenly, and then melt-extruded and granulated in a screw extruder to obtain the polypropylene composition.

10. The use of the polypropylene composition according to any one of claims 1 to 8 in the preparation of automotive decorative parts.

11. The application as described in claim 10, characterized in that, The automotive decorative components include at least one of the following: an integrated illuminated front fascia, an illuminated tailgate back panel, an illuminated door panel, an illuminated fender, an illuminated trim strip, and an intelligent control panel.

12. A type of automotive decorative component, characterized in that, Includes the polypropylene composition according to any one of claims 1 to 8.

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