Scratch-resistant automotive rubber-coated PC / ABS soft skin composite material and preparation method thereof

Abstract

The invention discloses a scratch-resistant automotive rubber-coated PC / ABS soft skin composite material and a preparation method thereof. The scratch-resistant automotive rubber-coated PC / ABS soft skin composite material comprises the following raw materials in parts by weight: 10-30 parts of hydrogenated styrene elastomer; 10 to 30 parts of a semi-hydrogenated styrene elastomer; 20 to 50 parts of a polyurethane elastomer; 20-50 parts of a plasticizer; 2 to 20 parts of a maleic anhydride graft; 1-5 parts of a scratch resistant agent; and 0.5-5 parts of an anti-oxidation and anti-ultraviolet auxiliary agent. The scratch-resistant rubber-coated PC / ABS soft skin composite material for the vehicle is prepared by a twin-screw composite modification process, has excellent scratch resistance, small cross scratch color difference and unobvious fingernail scratch marks, and is superior to common elastomer materials in the market; according to the scratch-resistant rubber-coated PC / ABS soft skin composite material for the vehicle, the production process is double-color injection molding integral forming, compared with a traditional coating process, the production steps are greatly simplified, and the forming period is shortened to 40-80 s from original 5-20 min.

Description

Technical Field

[0001] This invention relates to the field of polymer modification technology, and in particular to a scratch-resistant automotive-grade coated PC / ABS soft skin composite material and its preparation method. Background Technology

[0002] With rising consumer demands for upgrades and personalization, consumers are pursuing aesthetics (appearance, texture, etc.), comfort, tactile feel, slip resistance, and shock absorption, which single-material plastics can no longer satisfy (currently, two-color injection molded toothbrushes have replaced most plastic-handled toothbrushes). Genuine / imitation leather upholstery in automotive interiors is gradually becoming the mainstream trend. However, traditional interior upholstery processes involve numerous production steps, high costs, are prone to errors, suffer from poor consistency, and are extremely difficult to recycle, failing to effectively separate the leather from the thermoplastic frame, resulting in significant resource waste. Furthermore, as competition in the automotive industry intensifies, this leather upholstery process, due to its cumbersome production steps, cannot meet the increasingly stringent cost-reduction and efficiency-enhancing requirements of OEMs, leading to a demand for specialized soft rubber materials for overmolding. Injection molding overmolding processes are generally divided into two types: one is two-stage injection molding, requiring two sets of molds. This method is lower in cost and can be produced without upgrading production equipment, but its efficiency is relatively low; the second is two-color injection molding, which requires specialized production equipment and has higher processing efficiency. Automotive overmolding processes generally use two-color injection molding, which offers high production efficiency and good consistency.

[0003] Most commercially available two-color injection-molded TPE products suffer from numerous problems, including susceptibility to scratches, mold sticking, easy delamination, easy exudation, yellowing in light colors, and difficulty in processing large-area products. These issues severely hinder their widespread application in the automotive industry. To address these industry pain points, this invention designs a scratch-resistant automotive-grade overmolded PC / ABS soft skin composite material. This material possesses excellent scratch resistance, a good feel and molding processability, excellent light resistance, low odor, and can be used for light-colored automotive interior trim. Furthermore, it exhibits good recyclability, providing a solution for cost reduction, efficiency improvement, and environmental protection in automotive products. Summary of the Invention

[0004] The main objective of this invention is to provide a scratch-resistant, automotive-grade, overmolded PC / ABS soft-surface composite material and its preparation method, replacing traditional automotive interior overmolding solutions. This material exhibits excellent scratch resistance, a smooth feel, good molding and processing characteristics, excellent light resistance, low odor, and can be used in light-colored automotive interior trims. It also possesses good recyclability. The formulation of the soft-surface composite material is optimized through modification to improve its scratch resistance, processability, overmolding properties, odor control, and weather resistance, making it suitable for automotive interior and exterior products with high performance and aesthetic requirements.

[0005] To achieve the above objectives, the technical solution adopted in this invention is as follows: a scratch-resistant automotive-grade PC / ABS soft skin composite material, the raw materials of which, by weight, include: 10-30 parts of hydrogenated styrene elastomer; 10-30 parts of semi-hydrogenated styrene elastomer; 20-50 parts of polyurethane elastomer; 20-50 parts of plasticizer; 2-20 parts of maleic anhydride graft; 1-5 parts of scratch-resistant agent; and 0.5-5 parts of antioxidant and UV-resistant additives.

[0006] According to one embodiment of the present invention, the raw materials comprise, by weight, 20 parts of hydrogenated styrene elastomer matrix; 10 parts of semi-hydrogenated styrene elastomer; 30 parts of polyurethane elastomer; 25 parts of plasticizer; 10 parts of maleic anhydride graft; 3 parts of scratch-resistant agent; and 2 parts of antioxidant and UV-resistant additive.

[0007] According to an embodiment of the present invention, the hydrogenated styrene elastomer matrix is ​​selected from one or more of SEBS (hydrogenated styrene-butadiene-styrene triblock copolymer), SEPS (hydrogenated styrene-isoprene-styrene triblock copolymer), and SEEPS (hydrogenated styrene-ethylene-isoprene-styrene block copolymer), and its degree of hydrogenation is ≥98%.

[0008] According to an embodiment of the present invention, the semi-hydrogenated styrene elastomer has the following characteristics: the content of styrene blocks at both ends is 50-60%; the viscosity of the toluene solution at 25°C and the content of 15% is 350-400 MPa·s; the tensile strength is ≥30 MPa; the weight-average molecular weight is 100,000-150,000; and the degree of hydrogenation is 70-80%.

[0009] According to one embodiment of the present invention, the polyurethane elastomer is selected from one or more of polyether polyurethane, polyester polyurethane, aliphatic polyurethane, and polycaprolactone polyurethane.

[0010] According to an embodiment of the present invention, the raw materials for preparing the maleic anhydride graft are: 100 parts of polyolefin elastomer (POE), 1-10 parts of maleic anhydride monomer, 0.15-0.8 parts of dicumyl peroxide (DCP), 0.01-0.08 parts of antioxidant (168) and antioxidant (1010), and 0.01-0.3 parts of benzoyl peroxide (BPO). The melt index of the polyolefin elastomer (POE) is ≥30 g / 10 min, and the final melt index of the obtained maleic anhydride graft is ≥40 g / 10 min. According to one embodiment of the present invention, the plasticizer is a low-viscosity paraffin oil, wherein the kinematic viscosity of the paraffin oil at 40°C is less than or equal to 20 mm. 2 / s, flash point greater than or equal to 260℃, CP value greater than or equal to 60%.

[0011] According to one embodiment of the present invention, the scratch-resistant agent is selected from one or more of polyethylene wax, silicone masterbatch, silicone oil, erucamide, silica, polytetrafluoroethylene micro powder, and white fused alumina powder. The white fused alumina powder has a mesh size ≥ 500 mesh, and the silicone oil is a modified silicone oil with special reactive functional groups, with the brand name Evonik 4042 or a similar product.

[0012] According to one embodiment of the present invention, the antioxidant and UV stabilizer are selected from one or more of 1010, 1076, 1330, 1024, 168, 626, DLTDP, UV531, UV326, UV328, UV329, UV234, UV770, UV944, and UV622.

[0013] A method for preparing a scratch-resistant automotive-grade overmolded PC / ABS soft skin composite material, comprising the following steps: (1) Mix the appropriate weight parts of styrene elastomer matrix, semi-hydrogenated styrene elastomer, plasticizer, polyurethane elastomer, maleic anhydride graft, scratch resistant agent, antioxidant and UV resistant agent evenly through a high-speed mixer or coloring machine. (2) Use a peristaltic pump to inject the corresponding weight of distilled water through the pre-reserved injection holes in sections 2-8 of the screw; According to an embodiment of the present invention, the preparation method of the scratch-resistant automotive coated PC / ABS soft skin composite material further includes the following steps: (3) adjusting the feeding speed of the twin-screw extruder's loss-in-weight weighing system and the peristaltic pump speed to achieve the corresponding material ratio, wherein the twin-screw speed is 200~650 r / min, the twin-screw temperature is 180-250℃, the vacuum degree is less than or equal to 0.1 MPa, and the loss-in-weight weighing system is started first when the screw reaches a specific speed, and the peristaltic pump is started half a minute later. After underwater pelletizing, the scratch-resistant automotive coated PC / ABS soft skin composite material is obtained.

[0014] According to an embodiment of the present invention, the temperature of the coloring machine in step (1) is 20~60℃, the mixing speed is 10~500r / min, the temperature of the distilled water in step S200 is 10~20℃, and the peristaltic pump speed is 5~50r / min.

[0015] According to an embodiment of the present invention, the distilled water used in step (2) is used to help the material remove small molecules, but the amount used should not be too much, and it is necessary to ensure that the vacuum can be completely extracted.

[0016] According to an embodiment of the present invention, the maleic anhydride graft comprises the following steps: (1.a) The corresponding parts by weight of polyolefin elastomer matrix and antioxidant are granulated by twin-screw extrusion to prepare masterbatch A, with a rotation speed of 200~550 r / min and a temperature of 145~165℃; (1.b) The corresponding parts by weight of maleic anhydride monomer and peroxide are stirred and dissolved at 10~30℃ to prepare sulfide liquid B, wherein the stirring speed is 20~80r / min; (1.c) Grafting reaction: Masterbatch A and sulfurized liquid B are grafted and crosslinked in a twin-screw extruder to produce maleic anhydride grafts. The rotation speed in the twin-screw extruder is 300~600 r / min and the reaction temperature is 160~185℃. Maleic anhydride graft particles are produced by underwater pelletizing.

[0017] The preparation of the maleic anhydride graft comprises 100 parts of a polyolefin elastomer matrix (POE), 8 parts of maleic anhydride monomer, 0.5 parts of dicumyl peroxide (DCP), 0.2 parts of antioxidant (1076) and antioxidant (9228), and 0.1 parts of benzoyl peroxide (BPO). The polyolefin elastomer matrix is ​​characterized by a melt index greater than 30 g / 10 min at 230℃*2.16 kg.

[0018] A method for applying the scratch-resistant automotive overmolded PC / ABS soft skin composite material as described in claim 1, characterized by the following steps: adding the prepared elastomer composite material and PCABS plastic separately into a two-color injection molding machine; after the PCABS skeleton is formed, the second color of the elastomer composite material is injected; the molten elastomer material is injected onto the PCABS skeleton; after the injection is completed, the part is demolded to obtain an automotive interior part with a soft-touch surface; the injection temperature of the elastomer composite material is 200~220℃, the elastomer wall thickness is 1.5-2.5mm, and the cooling time is 0.2~3min.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The scratch-resistant automotive coated PC / ABS soft skin composite material of the present invention is prepared by a twin-screw composite modification process. It has excellent scratch resistance, small color difference when scratched by cross, and no obvious nail scratch marks, which is better than general elastomer materials on the market. (2) The scratch-resistant automotive coated PC / ABS soft skin composite material of the present invention is produced by two-color injection molding. Compared with the traditional coating process, the production steps are greatly simplified and the molding cycle is reduced from 5-20 minutes to 40-80 seconds. (3) Compared with traditional two-color injection molding materials, the scratch-resistant automotive overmolded PC / ABS soft skin composite material of the present invention has a soft feel, light color matching and yellowing resistance to meet the requirements of automotive interior, good appearance and firm overmolding. (4) The plasticizer used in this invention is low-viscosity paraffin oil. Due to its low kinematic viscosity, its composite material has high fluidity, the adjustable window of the injection molding process is increased, and it is easier to injection mold qualified automotive products. The product has a smooth feel. (5) The present invention adopts a water injection process. The peristaltic pump injects distilled water into the twin screw separately to absorb and dissolve the small molecule volatiles generated by the twin screw processing, and then removes them together at the vacuum exhaust port. The water injection volume can be precisely adjusted by adjusting the peristaltic pump speed, which effectively reduces the odor and VOC of the composite material. Detailed Implementation

[0020] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0021] As used herein, the terms “prepared from” and “comprising” are synonymous. The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0022] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1 to 5” is disclosed, the described range should be interpreted as including the ranges “1 to 4”, “1 to 3”, “1-2”, “1-2 and 4-5”, “1-3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0023] "Polymer" refers to a polymeric compound prepared by polymerizing the same or different types of monomers. The general term "polymer" includes the terms "homopolymer," "copolymer," "terpolymer," and "copolymer."

[0024] Example 1 A scratch-resistant automotive-grade PC / ABS soft skin composite material is prepared by a special twin-screw extrusion modification process. The raw materials of the composite elastomer, by weight, include: 20 parts hydrogenated styrene elastomer matrix; 10 parts semi-hydrogenated styrene elastomer; 30 parts polyurethane elastomer; 25 parts plasticizer; 10 parts maleic anhydride graft; 3 parts scratch-resistant agent; and 2 parts antioxidant and UV-resistant additives.

[0025] The styrene-based elastomer is SEBS elastomer; its weight-average molecular weight is 100,000-150,000; its degree of hydrogenation is ≥98%; and the plasticizer is low-viscosity paraffin oil with a kinematic viscosity of 20 mmHg at 40°C. 2 / s, flash point 260℃, straight-chain hydrocarbon (CP) content 60%; the semi-hydrogenated styrene elastomer contains 59% styrene, 41% butadiene, and has a hydrogenation saturation of 75%; the polyurethane elastomer is an aliphatic polyurethane with a melt index ≥5g / 10min, and its hard segment is hexamethylene diisocyanate (HDI); the scratch-resistant agent is a mixture of modified silicone oil (4042), polytetrafluoroethylene micro powder, and white corundum powder in a ratio of 1:1:1; the antioxidant and UV-resistant agent is a mixture of 626, 1010, UV234, and UV770 in a ratio of 1:1:2:2.

[0026] A method for preparing a scratch-resistant automotive-grade overmolded PC / ABS soft skin composite material, comprising the following steps: (1) Mix the appropriate weight parts of styrene elastomer matrix, semi-hydrogenated styrene elastomer, plasticizer, polyurethane elastomer, maleic anhydride graft, scratch resistant agent, antioxidant and UV resistant agent evenly through a high-speed mixer or coloring machine at a speed of 10~500r / min and a temperature of 20~60℃. (2) The corresponding weight of distilled water is injected through the pre-reserved injection holes in sections 2-8 of the screw using a peristaltic pump, wherein the speed of the peristaltic pump is 5~50 r / min; (3) Adjust the feed rate of the loss-in-weight weigher and the speed of the peristaltic pump of the twin-screw extruder (S300) to achieve the corresponding material ratio. The twin-screw speed is 200~650 r / min, the twin-screw temperature is 180-250℃, and the vacuum degree is less than or equal to 0.1 MPa. When the screw reaches a specific speed, the loss-in-weight weigher is turned on first, and the peristaltic pump is turned on half a minute later. After underwater pelleting, the scratch-resistant automotive overmolded PC / ABS soft skin composite material is obtained.

[0027] In step (1), the temperature of the coloring machine is 20~60℃ and the mixing speed is 10~500r / min. In step (2), the temperature of the distilled water is 10~20℃, the speed of the peristaltic pump is 5~50r / min, and the weight content is 2.5 parts.

[0028] The preparation method of the maleic anhydride includes the following steps: (1.a) The corresponding parts by weight of polyolefin elastomer matrix and antioxidant are granulated by twin-screw extrusion to prepare masterbatch A, with a rotation speed of 200~550 r / min and a temperature of 145~165℃; (1.b) The corresponding parts by weight of maleic anhydride monomer and peroxide are stirred and dissolved at 10~30℃ to prepare sulfide liquid B, wherein the stirring speed is 20~80r / min; (1.c) Grafting reaction: Masterbatch A and sulfurized liquid B are grafted and crosslinked in a twin-screw extruder to produce maleic anhydride grafts. The rotation speed in the twin-screw extruder is 300~600 r / min and the reaction temperature is 160~185℃. Maleic anhydride graft particles are produced by underwater pelletizing.

[0029] The preparation of the maleic anhydride graft comprises 100 parts of a polyolefin elastomer matrix (Dow POE8150), 8 parts of maleic anhydride monomer, 0.5 parts of dicumyl peroxide (DCP), 0.2 parts of antioxidant (1076) and antioxidant (9228), and 0.1 parts of benzoyl peroxide (BPO). The polyolefin elastomer matrix is ​​characterized by a melt index greater than 30 g / 10 min at 230°C * 2.16 kg.

[0030] A method for applying the scratch-resistant automotive overmolded PC / ABS soft skin composite material as described in claim 1, characterized by the following steps: adding the prepared elastomer composite material and PCABS plastic separately into a two-color injection molding machine; after the PCABS skeleton is formed, the second color of the elastomer composite material is injected; the molten elastomer material is injected onto the PCABS skeleton; after the injection is completed, the part is demolded to obtain an automotive interior part with a soft-touch surface; the injection temperature of the elastomer composite material is 200~220℃, the elastomer wall thickness is 1.5-2.5mm, and the cooling time is 0.2~3min.

[0031] Example 2-12 The preparation and application methods of Examples 2-12 are the same as those of Example 1, but the formula ratios are adjusted as shown in Table 1.

[0032] Table 1 Formulation ratios for Examples 2-12

[0033] Comparative Example 1 The comparative raw materials of a scratch-resistant automotive overmolded PC / ABS soft skin composite material are, by weight: 30 parts styrene elastomer; 25 parts plasticizer; 30 parts polyurethane elastomer; 10 parts polyolefin elastomer; and 2 parts antioxidant and UV resistant additives.

[0034] The styrene-based elastomer is SEBS elastomer with a weight-average molecular weight of 100,000-150,000 and a degree of hydrogenation ≥98%. The plasticizer is high-viscosity paraffin oil with a kinematic viscosity of 100 mmHg at 40°C. 2 / s, flash point 260℃, linear hydrocarbon (CP) content 60%; the polyurethane elastomer is an aromatic polyurethane with a melt index ≥5g / 10min, and its hard segment is diisocyanate (MDI); the polyolefin elastomer is a conventional 8-carbon POE material (Dow 8150); the antioxidant and UV stabilizer is a mixture of 626, 1010, UV234, and UV770 in a ratio of 1:1:2:2.

[0035] A comparative method for preparing a scratch-resistant automotive-grade overmolded PC / ABS soft skin composite material includes the following steps: (1) Mix the corresponding weight parts of styrene elastomer, plasticizer, polyurethane elastomer, polyolefin elastomer, antioxidant and UV stabilizer evenly using a high-speed mixer or coloring machine; (2) The well-mixed mixture is subjected to twin-screw extrusion and underwater pelletizing to obtain the comparative example of the scratch-resistant automotive overmolded PC / ABS soft skin composite material.

[0036] In step (1), the coloring machine temperature is 20~60℃ and the mixing speed is 10~500r / min. In step (2), the twin screw speed is 200~650r / min, the twin screw temperature is 180-250℃, and the vacuum degree is less than or equal to 0.1MPa.

[0037] Comparative Example 2 The preparation method of Comparative Example 2 is the same as that of Comparative Example 1, except that the styrene elastomer SEBS raw material is replaced with a mixture of styrene elastomer SEBS raw material and semi-hydrogenated styrene elastomer. The proportions of each component are as follows: 20 parts hydrogenated styrene elastomer matrix; 10 parts semi-hydrogenated styrene elastomer; 30 parts polyurethane elastomer; 25 parts plasticizer; 10 parts polyolefin elastomer; 2 parts antioxidant and UV resistant additives.

[0038] The styrene-based elastomer is SEBS with a weight-average molecular weight ≥ 150,000; the plasticizer is high-viscosity paraffin oil with a kinematic viscosity of 100 mmHg at 40°C. 2 / s, flash point 260℃, straight-chain hydrocarbon (CP) content 60%; the semi-hydrogenated styrene elastomer contains 59% styrene, 41% butadiene, and has a hydrogenation saturation of 75%; the polyolefin elastomer is a conventional 8-carbon POE material (Dow 8150); the antioxidant and UV stabilizer is a mixture of three substances, 626, 1010, UV234, and UV770, in a ratio of 1:1:2:2.

[0039] Comparative Example 3 The preparation method of Comparative Example 3 is the same as that of Comparative Example 2, except that the polyolefin elastomer is replaced with maleic anhydride graft, wherein the amount of maleic anhydride graft is 10 parts.

[0040] The preparation method of the maleic anhydride includes the following steps: (1.a) The corresponding parts by weight of polyolefin elastomer matrix and antioxidant are granulated by twin-screw extrusion to prepare masterbatch A, with a rotation speed of 200~550 r / min and a temperature of 145~165℃; (1.b) The corresponding parts by weight of maleic anhydride monomer and peroxide are stirred and dissolved at 10~30℃ to prepare sulfide liquid B, wherein the stirring speed is 20~80r / min; (1.c) Grafting reaction: Masterbatch A and sulfurized liquid B are grafted and crosslinked in a twin-screw extruder to produce maleic anhydride grafts. The rotation speed in the twin-screw extruder is 300~600 r / min and the reaction temperature is 160~185℃. Maleic anhydride graft particles are produced by underwater pelletizing.

[0041] The preparation of the maleic anhydride graft comprises 100 parts of a polyolefin elastomer matrix (Dow POE8150), 8 parts of maleic anhydride monomer, 0.5 parts of dicumyl peroxide (DCP), 0.2 parts of antioxidant (1076) and antioxidant (9228), and 0.1 parts of benzoyl peroxide (BPO). The polyolefin elastomer matrix is ​​characterized by a melt index greater than 30 g / 10 min at 230°C * 2.16 kg.

[0042] Comparative Example 4 The preparation method of Comparative Example 4 is the same as that of Comparative Example 3, except that the polyurethane elastomer is replaced with aliphatic polyurethane. The aliphatic polyurethane elastomer has a melt index ≥5g / 10min and its hard segment is hexamethylene diisocyanate (HDI), with an amount of 30 parts.

[0043] Comparative Example 5 The preparation method of Comparative Example 5 is the same as that of Comparative Example 4, except that a conventional scratch-resistant additive is added. The scratch-resistant additive is a silicone masterbatch with an effective content of 50%, which is a PP-based masterbatch and is used in an amount of 3 parts.

[0044] Performance testing: Tensile breaking strength was tested according to ISO 37 standard, using type 2 specimens at a tensile speed of 500 mm / min. Peel strength was tested according to VDI 2019 standard, with a specimen width of 20 mm and a test speed of 100 mm / min. Hardness was tested according to ISO 868 standard, with a reading time of 15 s. Cross scratch test was conducted according to PV 3952 standard, with a weight of 10 N and a scraper head of 1 mm. Melt flow index was tested according to ISO 1133-1 standard, at 190℃, with a weight of 2.16 kg. Abrasion test was conducted according to Taber rotational abrasion test, with a load of 1 kg and a rotation speed of 1000 rpm. Light aging test was conducted according to SAE J2412 standard, with a test cycle of 4 cycles. Odor test was conducted according to PV 3900 standard, at 80℃ for 2 hours, with a particle weight of 20 g. Five samples were tested, and the average value was taken. The performance test results of Examples 1-12 are shown in Table 2.

[0045] Table 2 Performance test results of Examples 1-12

[0046] The performance test results of Comparative Examples 1 to 5 are shown in Table 3.

[0047] Table 3 Performance test results of Comparative Examples 1-5

[0048] As can be seen from the performance comparison of Examples 1-3 and Comparative Examples 1 and 2 above, the present invention significantly increases the scratch resistance and abrasion resistance of the material by adding semi-hydrogenated styrene elastomer. The cross scratch resistance ΔL can be improved from the original 3.9 to a maximum of 0.8, and the abrasion resistance can be improved from the original -8.85mg to -0.25mg. However, as the amount of semi-hydrogenated styrene elastomer added increases, due to the presence of unhydrogenated double bond segments in its molecular chain, the double bonds are destroyed by light in the light aging test, causing ΔE to change from the best state of 1.5 to 5.3. At the same time, the odor also changes from the original 3.5 level to 3.6 level, which does not meet the requirements of automotive interiors. It can be seen that as the amount of semi-hydrogenated styrene elastomer added gradually increases, the scratch resistance and abrasion resistance gradually increase, but the light aging performance and odor of the material will deteriorate accordingly. There is an appropriate value for the amount of semi-hydrogenated styrene elastomer added. The performance comparisons of Examples 1, 4, and 5 and Comparative Examples 1, 2, and 3 show that the addition of polyurethane material significantly improves the peel strength of the material, increasing it from the original 0.6 MPa to a maximum of 7.2 MPa. The main advantage of aliphatic polyurethane elastomers compared to aromatic polyurethane elastomers is their more stable light aging ΔE, which meets the light requirements of automotive interiors. However, this material is expensive and has high hardness; excessive addition will lead to increased costs and poor feel and processability. The performance comparisons of Examples 1, 6, and 7 and Comparative Examples 4 and 5 show that the addition of low-viscosity plasticizers significantly improves the hardness and melt index of the material. Low-viscosity plasticizers slightly improve scratch and abrasion resistance. Furthermore, low-viscosity plasticizers provide a smoother, less sticky feel compared to high-viscosity plasticizers. However, as the addition amount increases, the scratch resistance, abrasion resistance, and mechanical properties of the composite material decrease. Therefore, plasticizers should be added as little as possible while maintaining processing fluidity. The performance comparisons of Examples 1, 8, and 9 and Comparative Examples 2 and 3 show that maleic anhydride grafts can significantly increase the scratch and abrasion resistance and mechanical properties of the materials. However, excessive addition of maleic anhydride grafts leads to a noticeably stronger odor in the materials. The performance comparisons of Examples 1, 10, and 11 and Comparative Examples 4 and 5 show that the self-prepared scratch-resistant agent significantly improves abrasion resistance compared to no agent or traditional silicone scratch-resistant additives, increasing abrasion loss from -8.85 mg without additives and -1.73 mg with traditional silicone masterbatch to -0.25 mg. However, with increasing dosage, the improvement in abrasion resistance tends to plateau, while increasing the risk of precipitation. The performance comparisons of Examples 1 and 12 show that the addition of antioxidants and UV stabilizers is essential. Without these additives, the ΔE in the light exposure test is 6.4, exceeding the ΔE≤3 limit for automotive interior light exposure tests. As can be seen from the comparison of odor performance of Example 1 and Comparative Examples 1 to 5 above, the production water injection process of the present invention has a certain effect on improving the odor of the material, improving it from the original odor of 4.0 to odor of 3.5, which meets the requirements of automotive interiors.The scratch-resistant automotive overmolded PC / ABS soft skin composite material of this invention is prepared through a twin-screw composite modification process, exhibiting excellent scratch resistance, minimal color difference in cross-scratch tests, and inconspicuous fingernail scratch marks, superior to general elastomer materials on the market. The production process of this scratch-resistant automotive overmolded PC / ABS soft skin composite material is a two-color injection molding process, which greatly simplifies the production steps compared to traditional overmolding processes, reducing the molding cycle from 5-20 minutes to 40-80 seconds. Compared to traditional two-color injection molded materials, this scratch-resistant automotive overmolded PC / ABS soft skin composite material has… The product has a soft feel, light color scheme, and is resistant to yellowing, meeting the requirements of automotive interiors. It has a good appearance and strong adhesive bonding. The plasticizer used in this invention is low-viscosity paraffin oil. Due to its low kinematic viscosity, the composite material has high fluidity, the adjustable window of the injection molding process is increased, and it is easier to injection mold automotive products with qualified appearance. The product has a smooth feel. This invention adopts a water injection process. A peristaltic pump separately injects distilled water into the twin-screw extruder to absorb and dissolve small molecule volatiles generated by twin-screw processing. The volatiles are then volatilized and discharged together at the vacuum exhaust port. The water injection volume can be precisely adjusted by adjusting the peristaltic pump speed, effectively reducing the odor and VOCs of the composite material.

[0049] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A scratch-resistant automotive-grade coated PC / ABS soft skin composite material, characterized in that, Its raw materials, by weight, include: 10-30 parts hydrogenated styrene elastomer; 10-30 parts semi-hydrogenated styrene elastomer; 20-50 parts polyurethane elastomer; 20-50 parts plasticizer; 2-20 parts maleic anhydride graft; 1-5 parts scratch resistant agent; and 0.5-5 parts antioxidant and UV resistant additive.

2. The scratch-resistant automotive-grade coated PC / ABS soft skin composite material according to claim 1, characterized in that, Its raw materials, by weight, include: 20 parts hydrogenated styrene elastomer matrix; 10 parts semi-hydrogenated styrene elastomer; 30 parts polyurethane elastomer; 25 parts plasticizer; 10 parts maleic anhydride graft; 3 parts scratch-resistant agent; and 2 parts antioxidant and UV-resistant additives.

3. The scratch-resistant automotive-grade coated PC / ABS soft skin composite material according to claim 1 or 2, characterized in that, The semi-hydrogenated styrene elastomer matrix is ​​selected from one or more of SEBS (hydrogenated styrene-butadiene-styrene triblock copolymer), SEPS (hydrogenated styrene-isoprene-styrene triblock copolymer), and SEEPS (hydrogenated styrene-ethylene-isoprene-styrene block copolymer), and its degree of hydrogenation is ≥98%.

4. The scratch-resistant automotive-grade coated PC / ABS soft skin composite material according to claim 3, characterized in that, The semi-hydrogenated styrene elastomer has the following characteristics: the content of styrene blocks at both ends is 50-60%; the viscosity of the toluene solution at 25°C with a content of 15% is 350-400 MPa·s; the tensile strength is ≥30 MPa; the weight-average molecular weight is 100,000-150,000; and the degree of hydrogenation is 70-80%.

5. A scratch-resistant automotive-grade coated PC / ABS soft skin composite material according to claim 1 or 2, characterized in that, The polyurethane elastomer is selected from one or more of polyether polyurethane, polyester polyurethane, aliphatic polyurethane, and polycaprolactone polyurethane.

6. A scratch-resistant automotive-grade coated PC / ABS soft skin composite material according to claim 5, characterized in that, The polyolefin elastomer (POE) has a melt index ≥30 g / 10 min, and the final melt index of the obtained maleic anhydride graft is ≥40 g / 10 min.

7. A scratch-resistant automotive-grade coated PC / ABS soft skin composite material according to claim 1 or 2, characterized in that, The raw materials for preparing the maleic anhydride graft are: 100 parts of polyolefin elastomer (POE), 1-10 parts of maleic anhydride monomer, 0.15-0.8 parts of dicumyl peroxide (DCP), 0.01-0.08 parts of antioxidant (168) and antioxidant (1010), and 0.01-0.3 parts of benzoyl peroxide (BPO).

8. A scratch-resistant automotive-grade coated PC / ABS soft skin composite material according to claim 1 or 2, characterized in that, The plasticizer is a low-viscosity paraffin oil, and the kinematic viscosity of the paraffin oil at 40°C is less than or equal to 20 mm. 2 / s, flash point greater than or equal to 260℃, CP value greater than or equal to 60%.

9. A scratch-resistant automotive-grade coated PC / ABS soft skin composite material according to claim 1 or 2, characterized in that, The scratch-resistant agent is selected from one or more of polyethylene wax, silicone masterbatch, silicone oil, erucamide, silica, polytetrafluoroethylene micro powder, and white corundum powder.

10. The scratch-resistant automotive-grade coated PC / ABS soft skin composite material according to claim 9, characterized in that, The white fused alumina powder has a mesh size of ≥500 mesh, and the silicone oil is a modified silicone oil with special reactive functional groups, with the brand name Evonik 4042 or similar products.

11. A scratch-resistant automotive-grade coated PC / ABS soft skin composite material according to claim 1 or 2, characterized in that, According to one embodiment of the present invention, the antioxidant and UV stabilizer are selected from one or more of 1010, 1076, 1330, 1024, 168, 626, DLTDP, UV531, UV326, UV328, UV329, UV234, UV770, UV944, and UV622.

12. A method for preparing a scratch-resistant automotive-grade coated PC / ABS soft skin composite material, characterized in that, It includes the following steps: (1) Mix the appropriate weight parts of styrene elastomer matrix, semi-hydrogenated styrene elastomer, plasticizer, polyurethane elastomer, maleic anhydride graft, scratch resistant agent, antioxidant and UV resistant agent evenly through a high-speed mixer or coloring machine. (2) Use a peristaltic pump to inject the corresponding weight of distilled water through the pre-reserved injection holes in sections 2-8 of the screw; (3) Adjust the feeding speed of the loss-in-weight weigher and the speed of the peristaltic pump of the twin-screw extruder to achieve the corresponding material ratio. The twin-screw speed is 200-650 r / min, the twin-screw temperature is 180-250℃, and the vacuum degree is less than or equal to 0.1 MPa. When the screw reaches a specific speed, the loss-in-weight weigher is turned on first, and the peristaltic pump is turned on half a minute later. After underwater pelleting, the scratch-resistant automotive coated PCABS soft skin composite material is obtained.

13. The method for preparing the scratch-resistant automotive overmolded PC / ABS soft skin composite material according to claim 12, characterized in that, The temperature of the coloring machine in step (1) is 20-60℃, the mixing speed is 10-500r / min, the temperature of the distilled water in step S200 is 10-20℃, and the speed of the peristaltic pump is 5-50r / min.

14. The method for preparing the scratch-resistant automotive overmolded PC / ABS soft skin composite material according to claim 12, characterized in that, The distilled water used in step (2) is used to help remove small molecules from the material, but the amount used should not be too much, and it is necessary to ensure that the vacuum can completely extract the substances.

15. The method for preparing the scratch-resistant automotive overmolded PC / ABS soft skin composite material according to claim 12, characterized in that, The maleic anhydride graft comprises the following steps: (1.a) The corresponding parts by weight of polyolefin elastomer matrix and antioxidant are granulated by twin-screw extrusion to prepare masterbatch A, with a rotation speed of 200-550 r / min and a temperature of 145-165℃. (1.b) The corresponding parts by weight of maleic anhydride monomer and peroxide are stirred and dissolved at 10-30°C to prepare sulfide liquid B, wherein the stirring speed is 20-80 r / min; (1.c) Grafting reaction: Masterbatch A and sulfurized liquid B are grafted and crosslinked in a twin-screw extruder to produce maleic anhydride grafts. The rotation speed in the twin-screw extruder is 300-600 r / min, and the reaction temperature is 160-185℃. Maleic anhydride graft particles are produced by underwater pelletizing.

16. The method for preparing the scratch-resistant automotive overmolded PC / ABS soft skin composite material according to claim 15, characterized in that, The preparation of the maleic anhydride graft comprises 100 parts of a polyolefin elastomer matrix (POE), 8 parts of maleic anhydride monomer, 0.5 parts of dicumyl peroxide (DCP), 0.2 parts of antioxidant 1076 and 0.2 parts of antioxidant 9228, and 0.1 parts of benzoyl peroxide (BPO). The polyolefin elastomer matrix is ​​characterized by a melt index greater than 30 g / 10 min at 230°C for 2.16 kg.

17. A method for applying a scratch-resistant automotive-grade coated PC / ABS soft skin composite material, characterized in that, The process includes the following steps: adding the prepared elastomer composite material and PCABS plastic separately into a two-color injection molding machine; after the PCABS skeleton is formed, the second color of the elastomer composite material is injected; the molten elastomer material is injected onto the PCABS skeleton; after the injection is completed, the part is demolded to obtain an automotive interior part with a soft-touch surface; the injection temperature of the elastomer composite material is 200-220℃, the elastomer wall thickness is 1.5-2.5mm, and the cooling time is 0.2-3min.

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