Ice-crack-imitating modified polypropylene composite material for automotive trim and preparation method of ice-crack-imitating modified polypropylene composite material

Abstract

The invention discloses an ice-crack-imitating modified polypropylene composite material for automotive interiors and a preparation method of the ice-crack-imitating modified polypropylene composite material. The modified polypropylene composite material consists of the following raw materials in parts by weight: 30-50 parts of homo-polypropylene; 20 to 30 parts of polypropylene random copolymer; 10 to 20 parts of whisker; 10 to 20 parts of a styrene-ethylene-butylene-styrene copolymer; 2 to 5 parts of LCP fiber; 0.2 to 2 parts of an antioxidant; 0.2 to 1 part of a compatilizer; 0.2 to 2 parts of an anti-UV agent; 0.2 to 0.5 part of a lubricant; the homo-polypropylene and the polypropylene random copolymer which are high in light transmittance are used as base materials, the transparent SEBS elastomer is selected to improve the toughness of a material system, the LCP fibers are added into the formula system, the dispersion morphology of the LCP fibers on the surface of the material is shown through the transparency of the light-transmitting polypropylene, and the appearance of imitating ceramic ice cracks is achieved. The ice-crack-imitating modified polypropylene composite material prepared by the preparation method disclosed by the invention can be widely applied to automotive interior products in combination with later color modeling and light source design.

Description

Technical Field

[0001] This invention relates to a method for preparing a modified polypropylene composite material with an ice-crack pattern for automotive interiors. The resulting material has a unique ice-crack appearance and high strength, and belongs to the field of polymer material processing and modification technology. Background Technology

[0002] In the field of automotive interior design, consumers are increasingly demanding high-quality, artistic, and personalized visual experiences. Decorative effects that mimic natural materials, such as wood grain, flocking, and especially ceramic crackle patterns, are highly favored due to their unique cultural connotations and aesthetic value.

[0003] Traditional techniques for achieving the ice crackle effect have the following limitations:

[0004] 1. Intermediate coat with imitation porcelain crackle effect: Publication number CN119101411A describes a specific intermediate coat that creates a crackle effect by relying on the uneven shrinkage rate of the paint itself. This reflects the traditional approach: achieving crackle aesthetics through additional coatings. However, this type of layer not only requires subsequent coating processes to cover defects, but also increases costs and is not environmentally friendly.

[0005] 2. Relying on special mold texture: Ice crack patterns are directly processed onto the surface of the product through mold etching. This method can only form a two-dimensional surface texture, lacking a three-dimensional feel and a transparent natural texture, and is prone to wear and dust accumulation with long-term use.

[0006] To overcome the aforementioned problems, this invention provides a modified polypropylene composite material for automotive interiors with an ice-crack pattern and its preparation method. This technology uses high-transparency polypropylene as the matrix and introduces LCP fibers during the basic process. Utilizing the different shrinkage characteristics of both materials during melting and cooling, micron-scale controllable crack structures are formed on the material surface and within the material. The transparency of polypropylene itself allows the dispersion morphology of LCP fibers (such as fiber orientation and distribution density) to be directly displayed on the material surface, achieving a three-dimensional visual effect similar to ceramic ice cracks without the need for additional coatings. Simultaneously, the high-temperature stability of LCP fibers avoids the performance degradation caused by the decomposition of plant fibers, and the material can be directly injection molded, eliminating the need for texture processing or coating steps. Summary of the Invention

[0007] To address the aforementioned problems, the purpose of this invention is to provide a modified polypropylene composite material for imitation ice crackle patterns in automotive interiors and a method for preparing the same. The resulting material utilizes the transparent nature of translucent polypropylene to showcase the appearance of LCP fibers, thus achieving a unique ice crackle-like aesthetic effect.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A modified polypropylene composite material with an ice-crack pattern for automotive interiors, made from the following raw materials in parts by weight:

[0010] 30-50 parts of homopolymer polypropylene;

[0011] 20-30 parts of random copolymer polypropylene;

[0012] 10-20 parts whiskers;

[0013] 10-20 parts of styrene-ethylene-butene-styrene copolymer (SEBS);

[0014] Antioxidant 0.2-2 parts;

[0015] Compatibilizer 0.2-1 part;

[0016] UV protectant 0.2-2 parts;

[0017] Lubricant 0.2-0.5 parts;

[0018] 0.5-5 parts LCP fiber.

[0019] in,

[0020] The homopolymer polypropylene has a melt flow rate between 10-100 g / 10 min at 230°C and 2.16 kg.

[0021] The random copolymer polypropylene described herein has a melt flow rate between 10-20 g / 10 min at 230°C and 2.16 kg.

[0022] The whiskers are one or more of basic magnesium sulfate whiskers and basic barium sulfate whiskers, with a length of 20-50 μm and a diameter of 2-5 μm.

[0023] The SEBS described is a linear structure, specifically requiring a viscosity of 400-600 cp for a 10% by mass toluene solution at 25°C.

[0024] The antioxidants include primary antioxidants and secondary antioxidants; the primary antioxidant is selected as hindered amines; the secondary antioxidant is one or more combinations of phosphites, thiodipropionates and thiols.

[0025] The compatibilizer is maleic anhydride-grafted polypropylene with an effective grafting activity of more than 3%. Specifically, the melt flow rate is between 5-20 g / 10 min at 230℃ and 2.16 kg.

[0026] The UV-resistant agent is a combination of one or more of the following: benzophenones, benzotriazoles, and hindered amines.

[0027] The lubricant is a compound of one or more of zinc stearate, magnesium stearate and calcium stearate.

[0028] The LCP fiber has a melting temperature of 300-330℃ and a length of 15-50mm.

[0029] The specific preparation method of the modified polypropylene composite material with ice-crack pattern for automotive interior is as follows:

[0030] (1) Mix the two types of polypropylene, compatibilizer and antioxidant evenly to obtain a mixture;

[0031] (2) Add the mixture to the main feed port of the twin-screw extruder, add whiskers, SEBS, lubricant, and UV stabilizer to side feed port 1#, and add LCP fibers to side feed port 2#; Figure 1 As shown.

[0032] (3) After setting the processing technology, melt blend, cool, granulate and dry to obtain the modified polypropylene composite material with ice crack pattern.

[0033] (4) The processing technology involved in step (3) is as follows: the processing temperatures of the twin-screw extruder in zones I to X are 125℃, 165℃, 185℃, 185℃, 200℃, 210℃, 225℃, 230℃, 230℃, and 220℃ respectively. The main screw speed is 300-450 r / min, and the water tank temperature is 23℃-50℃. The side feed port 1# should be located after the melting section and before the mixing section of the twin-screw extruder; the side feed port 2# should be located after the mixing section and before the metering section of the twin-screw extruder.

[0034] The advantages of this invention are:

[0035] 1. Mechanism Innovation: By utilizing the shrinkage difference between LCP fibers and transparent polypropylene matrix, an ice-crack-like structure is directly constructed at the internal molecular scale, providing a new design concept for automotive interiors.

[0036] 2. Material Innovation: By using LCP fiber with excellent thermal stability, the traditional easily decomposable plant fiber or complex resin blend system is replaced, making the formula simple and controllable, and widening the temperature range in the molding process.

[0037] 3. Technological innovation: It achieves the ice crack effect through injection molding without relying on coatings or mold etching. Attached Figure Description

[0038] Figure 1 This is a schematic diagram showing the location relationship of the feed ports in different zones of the screw.

[0039] Figure 2The appearance of the black ice crack pattern sample in Example 2. Detailed Implementation

[0040] The present invention will be further described in detail below by way of embodiments and comparative examples, but the invention is not limited to the scope of the embodiments described herein.

[0041] In the composite material formulations of the examples and comparative examples:

[0042] Polypropylene A is homopolymer polypropylene with a melt flow rate of approximately 10 g / 10 min, specifically grade PPBX3500 from SK Chemicals Co., Ltd., South Korea; Polypropylene B is random copolymer polypropylene with a melt flow rate of approximately 15 g / 10 min, specifically grade PP J8015 from Hyosung Group, South Korea; Whiskers are basic magnesium sulfate whiskers with a whisker length of 30 ± 5 μm, specifically grade MOS HIGE from Ube Materials Co., Ltd., Japan; SEBS has a linear structure with a melt flow rate of approximately 2 g / 10 min, specifically grade SEBS 9552 from Huizhou Li Changrong Rubber Co., Ltd.; Talc has a particle size of 3000 mesh, specifically grade SD700 from Suzhou Youkuang Plastic New Materials Co., Ltd.; POE has a 4C structural unit with a melt flow rate of approximately 2 g / 10 min, specifically grade POE from LG Chem Co., Ltd., South Korea. 168; The LCP fiber length is 20mm, and the specific grade is Shanghai Prit Composite Materials Co., Ltd. - LCLD150D006 N01512A; The additive package is a mixture of scratch-resistant additives, UV-resistant additives, antioxidants, compatibilizers, and lubricants. The scratch-resistant additive is Slime 306C, the UV-resistant agent is Xinxiu Chemical 5229, the antioxidants are BASF 168 and 1010, the compatibilizer is Huawen HW501, and the lubricant is Clariant. E-ZN;

[0043] In the composite material tests of the examples and comparative examples:

[0044] Tensile strength was tested according to ISO 527 standard at a tensile rate of 50 mm / min; flexural modulus was tested according to ISO 178 standard at a bending speed of 2 mm / min; notched impact test of simply supported beams was tested according to ISO 179 standard at a test temperature of 23℃; light transmittance and haze were tested according to GB / T 2410-2008 standard: method B photometer method was selected, and the size of the test sample was 50 mm * 50 mm * 2.5 mm.

[0045] Table 1. Material composition (weight percentage) of Examples 1-3 and Comparative Examples 1-2

[0046] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Polypropylene A 50 50 47.5 68 20 Polypropylene B 17.5 21 30 0 57.5 whiskers 10 10 10 10 0 SEBS 20 15 10 20 20 Additive package 2 2 2 2 2 LCP fiber 0.5 2 0.5 0 0.5

[0047] Table 2. Material property test results for Examples 1-5

[0048] Example 1 Example 2 Example 3 Example 4 Example 5 Transmittance (%) 29.4 22.9 26.9 32.3 42.6 Haze (%) 85.7 95.6 81.5 70.4 56.5 Tensile strength (MPa) 23.8 22.3 25.6 28.2 14.5 Flexural modulus (MPa) 1725 2087 1920 2250 1280 <![CDATA[Izod impact strength (kJ / m 2 )]]> 11.6 8.8 9.3 10.2 38.4

[0049] The material performance test results of Examples 1, 2, and 3 show the main performance distribution of the light-transmitting base material. The performance of the three formulations can meet the requirements of automotive interior trim parts and can be fine-tuned according to the design of different parts.

[0050] A comparison of the performance of Examples 1 and 3 and Comparative Example 1 reveals that the higher the content of homopolymer polypropylene A, the more significant the increase in tensile strength and flexural modulus of the composite material. However, the absence of copolymer polypropylene B and SEBS leads to a certain decrease in notched impact strength in Examples 3 and Comparative Example 1. Furthermore, Comparative Example 1, which did not contain LCP fibers, exhibited a slight increase in transmittance, a significant decrease in haze, and an overall improvement in light transmittance.

[0051] By comparing the performance of Examples 1 and 3 and Comparative Example 2, it can be found that although the addition of whiskers can effectively improve the overall tensile strength and flexural modulus of the material, it will significantly reduce the transmittance, and its effect is greater than that of LCP fibers.

Claims

1. A modified polypropylene composite material with an ice-crack pattern for use in automotive interiors, characterized in that: Made from raw materials comprising the following parts by weight: 30-50 parts of homopolymer polypropylene; 20-30 parts of random copolymer polypropylene; 10-20 parts whiskers; SEBS 10-20 copies; Antioxidant 0.2-2 parts; Compatibilizer 0.2-1 part; UV protectant 0.2-2 parts; Lubricant 0.2-0.5 parts; 0.5-5 parts LCP fiber.

2. The modified polypropylene composite material for imitation ice crack texture in automotive interiors according to claim 1, characterized in that: The homopolymer polypropylene has a melt flow rate between 10-100 g / 10 min at 230°C and 2.16 kg.

3. The modified polypropylene composite material for imitation ice crack texture in automotive interiors according to claim 1, characterized in that: The random copolymer polypropylene described herein has a melt flow rate between 10-20 g / 10 min at 230°C and 2.16 kg.

4. The modified polypropylene composite material with ice-crack pattern for automotive interiors according to claim 1, characterized in that: The whiskers are one or more of basic magnesium sulfate whiskers and basic barium sulfate whiskers, with a length of 20-50 μm and a diameter of 2-5 μm.

5. The modified polypropylene composite material for imitation ice crack texture in automotive interiors according to claim 1, characterized in that: The styrene-ethylene-butene-styrene copolymer has a linear structure, and the viscosity of a 10% by mass toluene solution at 25°C is 400-600 cp.

6. The modified polypropylene composite material for imitation ice crack texture in automotive interiors according to claim 1, characterized in that: The antioxidants include primary antioxidants and secondary antioxidants; the primary antioxidant is selected as hindered amines; the secondary antioxidant is one or more combinations of phosphites, thiodipropionates and thiols.

7. The modified polypropylene composite material for imitation ice crack texture in automotive interiors according to claim 1, characterized in that: The compatibilizer is maleic anhydride-grafted polypropylene with an effective grafting activity of more than 3%. Specifically, the melt flow rate is between 5-20 g / 10 min at 230℃ and 2.16 kg.

8. The modified polypropylene composite material for imitation ice crack texture in automotive interiors according to claim 1, characterized in that: The UV-resistant agent is a combination of one or more of the following: benzophenones, benzotriazoles, and hindered amines.

9. The modified polypropylene composite material for imitation ice crack texture in automotive interiors according to claim 1, characterized in that: The lubricant is a compound of one or more of zinc stearate, magnesium stearate and calcium stearate.

10. A modified polypropylene composite material for imitation ice crack texture in automotive interiors according to claim 1, characterized in that: The LCP fiber has a melting temperature of 300-330℃ and a length of 15-50mm.

11. The method for preparing the modified polypropylene composite material with ice-crack pattern for automotive interiors according to any one of claims 1-9, characterized in that, Includes the following steps: Step 1: Mix the two types of polypropylene, compatibilizer, and antioxidant until homogeneous to obtain a mixture; Step 2: Add the mixture to the main feed port of the twin-screw extruder, add whiskers, SEBS, lubricant and UV stabilizer to side feed port 1#, and add LCP fiber to side feed port 2#. Step 3: After setting the processing technology, melt blend, cool, granulate, and dry to obtain the modified polypropylene composite material with ice crack pattern.

12. The method for preparing a modified polypropylene composite material with an ice-crack pattern for automotive interiors according to claim 11, characterized in that: The processing temperatures of the twin-screw extruders in zones I to X are 125℃, 165℃, 185℃, 185℃, 200℃, 210℃, 225℃, 230℃, 230℃, and 220℃, respectively; the main screw speed is 300-450 r / min, and the water bath temperature is 23℃-50℃. The side feed port 1# should be located after the melting section and before the mixing section of the twin-screw extruder to prevent the whiskers from being subjected to excessive shearing, which would lead to a decrease in performance. The side feed port 2# should be located after the mixing section and before the metering section of the twin-screw extruder to prevent the LCP fibers from being subjected to excessive shearing, which would lead to a decrease in the aspect ratio and make it difficult for cracks to appear on the surface.

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