High surface tension modified polypropylene material and application thereof

Abstract

The invention discloses a high-surface-tension modified polypropylene material and application thereof, and belongs to the technical field of modified polypropylene materials.The high-surface-tension modified polypropylene material is composed of a component A and a component B. The component A is a component A, and the component B is a component B, the component A is prepared from the following raw materials in parts by mass: 50 to 90 parts of polypropylene, 5 to 30 parts of talcum powder, 5 to 15 parts of polyolefin elastomer, 2 to 5 parts of precipitated white carbon black, 2 to 5 parts of polar polymer and 0.2 to 0.8 part of antioxidant; wherein the component B is formed by melting and mixing an acrylate microsphere foaming agent and polyethylene wax according to the mass ratio of 1: 1. Aiming at the pain points of poor compatibility of a polypropylene base material and polar viscose, high cost and insufficient timeliness of a plasma treatment process, mechanical property reduction caused by a single polar auxiliary agent and the like in the application of the automotive interior trim part, the invention provides a novel material formula design and process optimization. The invention provides a modified polypropylene material with high surface tension, lasting adhesion and excellent mechanical properties.

Description

Technical Field

[0001] The present invention belongs to the technical field of modified polypropylene materials, and particularly relates to a high surface tension modified polypropylene material and its application. Background Art

[0002] Automobile interior parts are gradually designed with an injection-molded polypropylene (PP) substrate covered with suede or leather. However, due to the non-polar characteristics of PP, the surface tension is low, and the compatibility with polar adhesives is poor. Plasma treatment is required to improve the bonding strength.

[0003] The existing plasma treatment process has high costs and poor timeliness. The surface tension decays over time after treatment, resulting in easy delamination of the coated parts during long-term use. Although adding a single polar additive can increase the surface tension, it will significantly reduce the toughness of the material.

[0004] There is an urgent need to develop a modified PP material with high surface tension, durable adhesiveness, and mechanical balance to replace plasma treatment and meet the industrial requirements of automobile interiors. Summary of the Invention

[0005] The purpose of the present invention is to provide a high surface tension modified polypropylene material and its application to solve the problems in the background art.

[0006] The purpose of the present invention can be achieved by the following technical solutions: A high surface tension modified polypropylene material, which is composed of the following raw materials in mass percentages: 88% - 89% of component A; 11% - 12% of component B; The component A includes the following raw materials in parts by mass: 50 - 90 parts of polypropylene, 5 - 30 parts of talcum powder, 5 - 15 parts of polyolefin elastomer, 2 - 5 parts of precipitated silica, 2 - 5 parts of polar polymer, and 0.2 - 0.8 part of antioxidant; The component B is prepared by melting and mixing an acrylate microsphere foaming agent and polyethylene wax in a mass ratio of 1:1.

[0007] Further, the polar polymer is one of ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, and chlorinated polyethylene.

[0008] Further, the antioxidant is prepared by mixing antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0009] Further, the acrylate microsphere foaming agent is prepared by the following steps: A1. Add polyvinyl alcohol to deionized water, heat up to 60 °C and stir for 30 min to form an aqueous phase; mix methyl methacrylate, divinylbenzene, azodicarbonamide, and benzoyl peroxide evenly, and ultrasonically disperse for 10 min to form an oil phase; pour the oil phase into the aqueous phase, emulsify at a speed of 800 rpm to form droplets with a particle size of 20 - 50 μm, heat up to 75 - 80 °C and react for 3 - 4 h, then raise the temperature to 85 - 90 °C and cure for 2 - 3 h to obtain a reaction solution. After the reaction solution is cooled, centrifuged, washed, and vacuum dried, core layer microspheres are obtained. A2. Dissolve ethylene - ethyl acrylate in xylene, stir at 70 - 80 °C for 1 - 2 h to obtain an ethylene - ethyl acrylate solution; then immerse the core layer microspheres in the ethylene - ethyl acrylate solution, maintain a vacuum of - 0.08 MPa for 20 - 30 min, then place in an oven at 50 °C and dry for 2 h, and then raise the temperature to 102 - 105 °C for heat treatment for 1 - 2 h to obtain intermediate layer microspheres. A3. Dry - mix ethylene - vinyl acetate copolymer grafted maleic anhydride, dibutyltin dilaurate with the intermediate layer microspheres to obtain a mixture, and use a twin - screw extruder to extrude and granulate the mixture to obtain an acrylate microsphere foaming agent.

[0010] Further, the mass - part dosage ratio of the deionized water, polyvinyl alcohol, methyl methacrylate, divinylbenzene, azodicarbonamide, and benzoyl peroxide in A1 is 500:3 - 5:100:8 - 10:22 - 25:0.8 - 1.0.

[0011] Further, the mass - part dosage ratio of the ethylene - ethyl acrylate, xylene, and core layer microspheres in A2 is 30 - 40:150:100.

[0012] Further, the mass - part dosage ratio of the ethylene - vinyl acetate copolymer grafted maleic anhydride, dibutyltin dilaurate, and intermediate layer microspheres in A3 is 20:0.3 - 0.5:100.

[0013] Further, the parameter settings of the twin - screw extruder in A3 are as follows: set temperature: zone 1 is 120 - 125 °C, zone 2 is 140 - 150 °C, zone 3 is 155 - 160 °C; set speed: 80 - 100 rpm.

[0014] Further, the application of the high - surface - tension modified polypropylene material includes the following steps: S1. Weigh each raw material according to mass parts, mix evenly, and then place it in a twin - screw extruder, and extrude and granulate at a temperature of 180 - 230 °C to obtain component A. S2. Mix the acrylate microsphere foaming agent and polyethylene wax according to a mass ratio of 1:1, heat to 90 - 95 °C, stir constantly at a constant temperature until completely melted, and then cool to obtain component B. S3. Mix component A and component B according to the mass percentage to obtain a modified polypropylene material, and then injection mold the modified polypropylene material to obtain a modified polypropylene injection molding part; S4. Roll coat a 40 - 50 μm waterborne polyurethane coating adhesive on the surface of the modified polypropylene injection molding part. After the roll coating is completed, lay suede material in the coated area. After the laying is completed, let it stand at room temperature for 24 h, and then use a hot press to carry out pressure holding at 60 - 80 °C and 0.3 - 0.5 MPa for 10 - 20 s. After the pressure holding is completed, after cooling, flash trimming, and surface cleaning, a suede automotive interior part is obtained.

[0015] Furthermore, the grade of the waterborne polyurethane coating adhesive is AH - 0203DB.

[0016] Advantages of the present invention: Aiming at the pain points in the application of automotive interior parts, such as poor compatibility between polypropylene (PP) substrate and polar adhesives, high cost and insufficient timeliness of plasma treatment process, and mechanical property decline caused by single polar additives, through innovative material formulation design and process optimization, the present invention proposes a modified polypropylene material with high surface tension, persistent adhesiveness, and excellent mechanical properties. Its beneficial effects and creative breakthroughs are mainly reflected in the following aspects: 1. Multi - dimensional synergistic effect of core - shell structure microsphere foaming agent: Technical breakthrough: The acrylate microsphere foaming agent in component B adopts a three - layer composite structure design of "core - layer foaming - middle - layer compatibilization - shell - layer polar grafting", realizing the dual optimization of surface polarity improvement and material internal toughness.

[0017] (1) Core - layer microspheres (methyl methacrylate - based): The azodicarbonamide foaming agent expands when heated during processing, forming micron - level pores (20 - 50 μm) on the material surface, significantly increasing the specific surface area and providing mechanical anchoring points for subsequent adhesion.

[0018] (2) Middle - layer (ethylene - ethyl acrylate coating): Through vacuum impregnation and melt coating processes, polar chain segments (ethyl acrylate) penetrate into the microsphere pores, forming a continuous polar interface and enhancing the compatibility with the polypropylene matrix in component A (the peel strength is increased to 17.5 - 19.1 N / 25mm).

[0019] (3) Shell - layer (maleic anhydride - grafted EVA): The grafted carboxylic acid groups migrate to the material surface directionally during injection molding, forming stable polar active sites (the surface tension reaches 48.2 - 51.0 mN / m), and inhibiting surface polarity attenuation through chemical bonding, solving the problem of poor timeliness of traditional plasma treatment.

[0020] In the traditional technology, blowing agents are only used to reduce density or improve processing fluidity. However, through structural design, the microsphere blowing agent of the present invention integrates the triple functions of "physical anchoring", "chemical polarity", and "interface compatibilization" for the first time, achieving a simultaneous breakthrough in surface tension and adhesion persistence without sacrificing mechanical properties (elongation at break: 215% - 240%).

[0021] 2. Synergistic dispersion system of polar polymer and inorganic filler: Technical breakthrough: Introduce a composite system of precipitated silica (2 - 5 parts) and polar polymers (EAA / EVA / CPE) into Component A. By coating the surface of silica with polar polymers, a "polar - inorganic" network structure is constructed.

[0022] (1) Nano - dispersion effect of silica: The specific surface area of silica is as high as 200 - 400 m² / g. The silanol groups on its surface form hydrogen bonds with the carboxyl / ester groups of polar polymers, inhibiting the agglomeration of polar additives and ensuring the uniform distribution of polar groups in the matrix.

[0023] (2) Mechanical property compensation mechanism: The rigid particles of silica and polyolefin elastomer (POE8150) form a "rigid - flexible" interpenetrating network. While increasing the tensile strength (28.4 - 30.7 MPa), the elastomer absorbs impact energy (-30°C impact strength still reaches 10.2 - 13.5 KJ / m²), breaking through the bottleneck of the sharp decline in toughness of traditional polar - modified PP.

[0024] In the traditional technology, the addition of polar additives and inorganic fillers often leads to phase separation (such as the interfacial defects between CPE and talc powder). However, in the present invention, through the pre - compounding of polar polymers and silica, nano - level dispersion and interface strengthening are achieved, enabling the material to be synergistically optimized in terms of polarity, strength, and toughness.

[0025] 3. Melt - mixing process and surface migration control of Component B Technical breakthrough: Component B (acrylate microsphere blowing agent + polyethylene wax) adopts a melt - mixing and then cooling - pelletizing process. Utilizing the migration characteristics of polyethylene wax, the microspheres are guided to be distributed directionally on the surface layer of the material during the injection molding process.

[0026] (1) Migration kinetics control: Polyethylene wax (melting point 90 - 95°C) melts at the high temperature of injection molding and carries the microspheres to migrate to the low - temperature region (the mold surface), forming a gradient distribution structure, maximizing the utilization of the polar function of the microspheres (surface tension is increased to 51 mN / m, approaching the level of PET).

[0027] (2) Processing property optimization: Polyethylene wax acts as a lubricant, reducing the melt viscosity, avoiding processing difficulties caused by high - filled talc powder, and not affecting the surface finish of the final product.

[0028] In traditional modification processes, it is difficult to achieve both the uniform dispersion and functional distribution of polar components. However, through the directional migration design of component B, the present invention realizes the selective enrichment of functional microspheres without complex surface treatment, significantly reducing production costs and featuring high process stability.

[0029] 4. Environmental friendliness throughout the life cycle and industrial adaptability Technical breakthrough: The direct bonding process of aqueous polyurethane adhesive (AH-0203DB) and modified PP is adopted to avoid the VOC emissions of traditional solvent-based adhesives. At the same time, the high surface tension of the material itself ensures the bonding reliability (the peel strength reaches 19.1 N / 25mm, exceeding the industry standard of 12 N / 25mm).

[0030] All in all, the core innovation of the present invention lies in: through the collaborative innovation of "core-shell microsphere structure design", "polar-inorganic composite dispersion system", and "component directional migration process", it breaks through the technical bottlenecks of "high polarity necessarily damages toughness" and "surface treatment depends on external processes" in traditional PP modification technologies, and realizes the balance between spontaneous surface functionalization and mechanical properties of the material. Its technical route has significant industrial value in the field of automotive interiors and is expected to be extended to high-end application scenarios such as home appliances, electronic packaging, etc. with strict requirements for surface bonding and mechanical properties. Detailed implementation manners

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0032] Example 1 Preparation of acrylate microsphere foaming agent: A1. Preparation of core-layer microspheres: Add 500 parts (parts by mass, the same below) of deionized water and 3 parts of polyvinyl alcohol (grade: PVA1788) to the reaction kettle, heat up to 60 °C and stir for 30 min to dissolve, forming an aqueous phase; mix 100 parts of methyl methacrylate, 8 parts of divinylbenzene, 22 parts of azodicarbonamide, and 0.8 part of benzoyl peroxide evenly, and ultrasonically disperse for 10 min (power 300W) to form an oil phase; pour the oil phase into the aqueous phase, emulsify at a rotation speed of 800 rpm to form liquid droplets with a particle size of 50 μm, heat up to 75 °C and react for 3 h, then rise to 85 °C for curing for 2 h to obtain a reaction solution. After the reaction solution is cooled to 40 °C, it is centrifuged and washed 3 times with 50 °C hot water, and then vacuum dried to obtain core-layer microspheres; A2. Intermediate layer coating: Dissolve 30 parts of ethylene-ethyl acrylate (grade: Arkema 5500 from France) in 150 parts of xylene, stir at 70 °C for 1 h to obtain an ethylene-ethyl acrylate solution; then immerse 100 parts of the core layer microspheres in the ethylene-ethyl acrylate solution, maintain a vacuum of -0.08 MPa for 20 min to allow the solution to penetrate into the pores of the microspheres, then place them in an oven at 50 °C for 2 h to remove the solvent, and then raise the temperature to 102 °C for heat treatment for 1 h to melt and coat the surface with ethylene-ethyl acrylate, obtaining intermediate layer microspheres; A3. Shell grafting: Dry mix 20 parts of ethylene-vinyl acetate copolymer grafted maleic anhydride (grade: Dow 39E660), 0.3 parts of dibutyltin dilaurate with 100 parts of the intermediate layer microspheres to obtain a mixture. Use a twin-screw extruder, set the temperature: zone 1 at 120 °C, zone 2 at 140 °C, zone 3 at 155 °C, and the rotation speed at 80 rpm to extrude and pelletize the mixture to obtain acrylate microsphere foaming agent.

[0033] Example 2 Preparation of acrylate microsphere foaming agent: A1. Core layer microsphere preparation: Add 500 parts (by mass, the same below) of deionized water and 5 parts of polyvinyl alcohol (grade: PVA1788) to a reaction kettle, heat up to 60 °C and stir to dissolve for 30 min to form an aqueous phase; mix 100 parts of methyl methacrylate, 9 parts of divinylbenzene, 24 parts of azodicarbonamide, and 1.0 part of benzoyl peroxide evenly, and ultrasonically disperse for 10 min (power 300W) to form an oil phase; pour the oil phase into the aqueous phase, emulsify at a rotation speed of 800 rpm to form liquid droplets with a particle size of 20 μm, heat up to 75 °C and react for 4 h, then raise the temperature to 85 °C for curing for 3 h to obtain a reaction solution. After the reaction solution is cooled to 40 °C, it is centrifuged, washed 3 times with hot water at 50 °C, and dried in vacuum to obtain core layer microspheres; A2. Intermediate layer coating: Dissolve 35 parts of ethylene-ethyl acrylate (grade: Arkema 5500 from France) in 150 parts of xylene, stir at 75 °C for 2 h to obtain an ethylene-ethyl acrylate solution; then immerse 100 parts of the core layer microspheres in the ethylene-ethyl acrylate solution, maintain a vacuum of -0.08 MPa for 30 min to allow the solution to penetrate into the pores of the microspheres, then place them in an oven at 50 °C for 2 h to remove the solvent, and then raise the temperature to 104 °C for heat treatment for 2 h to melt and coat the surface with ethylene-ethyl acrylate, obtaining intermediate layer microspheres; A3. Shell grafting: Dry mix 20 parts of ethylene-vinyl acetate copolymer grafted maleic anhydride (grade: Dow 39E660), 0.5 parts of dibutyltin dilaurate with 100 parts of the intermediate layer microspheres to obtain a mixture. Use a twin-screw extruder, set the temperature: zone 1 at 125 °C, zone 2 at 145 °C, zone 3 at 155 °C, and the rotation speed at 100 rpm to extrude and pelletize the mixture to obtain acrylate microsphere foaming agent.

[0034] Example 3 Preparation of acrylate microsphere foaming agent: A1. Preparation of core layer microspheres: Add 500 parts (parts by mass, the same below) of deionized water and 5 parts of polyvinyl alcohol (grade: PVA1788) into a reaction kettle, heat up to 60 °C and stir to dissolve for 30 min to form an aqueous phase; mix 100 parts of methyl methacrylate, 10 parts of divinylbenzene, 25 parts of azodicarbonamide, and 1.0 part of benzoyl peroxide evenly, and ultrasonically disperse for 10 min (power 300W) to form an oil phase; pour the oil phase into the aqueous phase, emulsify at a speed of 800 rpm to form droplets with a particle size of 40 μm, heat up to 80 °C and react for 4 h, then rise to 90 °C for curing for 3 h to obtain a reaction solution. After the reaction solution is cooled to 50 °C, it is centrifuged and washed 3 times with hot water at 50 °C, and then vacuum dried to obtain core layer microspheres; A2. Intermediate layer coating: Dissolve 40 parts of ethylene-ethyl acrylate (grade: Arkema 5500, France) in 150 parts of xylene, stir at 80 °C for 2 h to obtain an ethylene-ethyl acrylate solution; then immerse 100 parts of core layer microspheres in the ethylene-ethyl acrylate solution, maintain a vacuum degree of -0.08 MPa for 30 min to allow the solution to penetrate into the pores of the microspheres, then place it in an oven at 50 °C to dry for 2 h to remove the solvent, and then heat up to 105 °C for heat treatment for 2 h to melt and coat the surface with ethylene-ethyl acrylate to obtain intermediate layer microspheres; A3. Shell layer grafting: Dry mix 20 parts of ethylene-vinyl acetate copolymer grafted maleic anhydride (grade: Dow 39E660), 0.5 part of dibutyltin dilaurate with 100 parts of intermediate layer microspheres to obtain a mixture. Use a twin-screw extruder, set the temperature: zone 1 at 125 °C, zone 2 at 150 °C, zone 3 at 160 °C, and the rotation speed at 100 rpm to extrude and granulate the mixture to obtain acrylate microsphere foaming agent.

[0035] Example 4 Production of suede automotive interior parts, including the following steps: S1. Preparation of component A: First, component A includes the following raw materials in parts by mass: 50 parts of polypropylene (grade: K4912), 5 parts of talcum powder, 5 parts of polyolefin elastomer (grade: POE8150), 2 parts of precipitated silica, 2 parts of ethylene-ethyl acrylate copolymer (grade: EAA378), and 0.2 part of antioxidant. Among them, the antioxidant is composed of antioxidant 1010 and antioxidant 168 mixed in a mass ratio of 1:1. Weigh each raw material according to the above parts by mass, mix evenly, and then place it in a twin-screw extruder and extrude and granulate at a temperature of 180 °C to obtain component A.

[0036] S2. Preparation of Component B: Mix the acrylate microsphere foaming agent prepared in Example 1 and polyethylene wax in a mass ratio of 1:1, heat to 90 °C, stir at a constant temperature until completely melted, and then cool to obtain Component B.

[0037] S3. Preparation of modified polypropylene injection-molded parts: Mix 89% (by mass percentage) of Component A and 11% (by mass percentage) of Component B in proportion to obtain a modified polypropylene material. After injection molding the modified polypropylene material, a modified polypropylene injection-molded part is obtained. Then, samples of the same batch of modified polypropylene materials are taken for testing, and the surface tension and mechanical properties of the modified polypropylene materials are tested. The specific test process and test results are as follows: (1) Testing surface tension: Specimen preparation: Inject the modified polypropylene material into a 100 mm × 100 mm × 2 mm flat plate; Testing process: According to standard ISO 8296, using the contact angle method, and using a Dataphysics OCA20 contact angle meter, test the contact angles of deionized water (polar liquid) and diiodomethane (non-polar liquid) on the surface of the specimen, and calculate the surface tension through the Owens-Wendt equation. After detection and calculation, the average surface tension of the modified polypropylene material prepared in the present invention is 48.2 mN / m.

[0038] (2) Testing mechanical properties: Tensile property testing process: According to standard ISO 527-2, inject the modified polypropylene material into a Type 1A dumbbell specimen, with a tensile rate of 50 mm / min, and measure the elongation at break and tensile strength. After detection, the average elongation at break of the modified polypropylene material prepared in the present invention is 215%, and the average tensile strength is 28.4 MPa.

[0039] Impact property testing process: According to standard ISO 180, inject the modified polypropylene material into a notched specimen of 80 mm × 10 mm × 4 mm, and measure the Izod impact strength at 23 °C and -30 °C. After detection, the average Izod impact strength (23 °C) of the modified polypropylene material prepared in the present invention is 32.8 KJ / m 2 , and the average Izod impact strength (-30 °C) is 10.2 KJ / m 2 .

[0040] S4. Produce suede automotive interior parts: Roll coat a 40-μm waterborne polyurethane coating adhesive (grade: AH-0203DB) on the surface of the modified polypropylene injection molded parts. After the roll coating is completed, lay suede material in the coated area. After laying, let it stand at room temperature for 24 h until the waterborne polyurethane coating adhesive is completely cured. Then, use a hot press to carry out pressure holding at 60 °C and 0.3 MPa for 10 s. After the pressure holding is completed, through cooling, flash trimming, and surface cleaning, suede automotive interior parts are obtained. Then, sample and test the suede automotive interior parts produced in the same batch, and test the bonding performance between the suede material and the modified polypropylene injection molded parts. The specific test process and test results are as follows: Test process: According to the standard GB / T 2791-1995, adopt 180° peel strength test, peel the suede automotive interior parts at a rate of 300 mm / min, and record the average peel strength. After testing, the average peel strength of the suede automotive interior parts produced by the present invention is 17.5 N / 25 mm.

[0041] Example 5 Produce suede automotive interior parts, including the following steps: S1. Prepare component A: First, component A includes the following raw materials in parts by mass: 80 parts of polypropylene (grade: K4912), 15 parts of talcum powder, 10 parts of polyolefin elastomer (grade: POE8150), 4 parts of precipitated silica, 4 parts of ethylene-vinyl acetate copolymer (grade: EVA210), and 0.8 part of antioxidant. Among them, the antioxidant is composed of antioxidant 1010 and antioxidant 168 mixed in a mass ratio of 1:1. Weigh each raw material according to the above parts by mass, mix evenly, and then place it in a twin-screw extruder and extrude and pelletize at a temperature of 210 °C to obtain component A.

[0042] S2. Prepare component B: Mix the acrylate microsphere foaming agent prepared in Example 2 and polyethylene wax in a mass ratio of 1:1, heat to 90 °C, stir constantly at a constant temperature until completely melted, and then cool to obtain component B.

[0043] S3. Prepare modified polypropylene injection molded parts: Mix 88% (mass percentage) of component A and 12% (mass percentage) of component B in proportion to obtain a modified polypropylene material. After the modified polypropylene material is injection molded, modified polypropylene injection molded parts are obtained. Then, sample and test the same batch of modified polypropylene materials, and test the surface tension and mechanical properties of the modified polypropylene materials. The specific test process and test results are as follows: (1) Test the surface tension: Specimen preparation: Inject the modified polypropylene material into a 100 mm × 100 mm × 2 mm flat plate; Testing process: According to the standard ISO 8296, using the contact angle method and the Dataphysics OCA20 contact angle meter, the contact angles of deionized water (polar liquid) and diiodomethane (non-polar liquid) on the surface of the specimen were measured. The surface tension was calculated through the Owens-Wendt equation. After detection and calculation, the average surface tension of the modified polypropylene material prepared by the present invention was 51.0 mN / m.

[0044] (2) Testing mechanical properties: Tensile property testing process: According to the standard ISO 527-2, the modified polypropylene material was injection molded into 1A dumbbell specimens, with a tensile rate of 50 mm / min. The elongation at break and tensile strength were measured. After detection, the average elongation at break of the modified polypropylene material prepared by the present invention was 240%, and the average tensile strength was 30.7 MPa.

[0045] Impact property testing process: According to the standard ISO 180, the modified polypropylene material was injection molded into notched specimens of 80 mm × 10 mm × 4 mm. The cantilever beam impact strength at 23°C and -30°C was measured. After detection, the average cantilever beam impact strength (23°C) of the modified polypropylene material prepared by the present invention was 35.1 KJ / m 2 , and the average cantilever beam impact strength (-30°C) was 13.5 KJ / m 2 .

[0046] S4. Producing suede automotive interior parts: Roll coat 50 μm of waterborne polyurethane coating adhesive (grade: AH-0203DB) on the surface of the modified polypropylene injection molded parts. After the roll coating is completed, lay the suede material in the coated area. After laying, let it stand at room temperature for 24 h until the waterborne polyurethane coating adhesive is completely cured. Then, use a hot press to carry out pressure holding at 70°C and 0.5 MPa for 20 s. After the pressure holding is completed, after cooling, flash trimming, and surface cleaning, suede automotive interior parts are obtained. Then, sample and test the suede automotive interior parts produced in the same batch to detect the bonding performance between the suede material and the modified polypropylene injection molded parts. The specific testing process and test results are as follows: Testing process: According to the standard GB / T 2791-1995, using the 180° peel strength test, the suede automotive interior parts were peeled at a rate of 300 mm / min, and the average peel strength was recorded. After detection, the average peel strength of the suede automotive interior parts produced by the present invention was 19.1 N / 25mm.

[0047] Example 6 Producing suede automotive interior parts, including the following steps: S1. Preparation of Component A: First, Component A includes the following raw materials in parts by mass: 90 parts of polypropylene (grade: K4912), 30 parts of talc powder, 15 parts of polyolefin elastomer (grade: POE8150), 5 parts of precipitated silica, 5 parts of chlorinated polyethylene (grade: CPE135A), and 0.8 part of antioxidant. Among them, the antioxidant is composed of antioxidant 1010 and antioxidant 168 mixed in a mass ratio of 1:1. Weigh each raw material according to the above parts by mass, mix them evenly, and then place them in a twin-screw extruder, and extrude and pelletize at a temperature of 230 °C to obtain Component A.

[0048] S2. Preparation of Component B: Mix the acrylate microsphere foaming agent prepared in Example 3 and polyethylene wax in a mass ratio of 1:1, heat to 95 °C, stir at a constant temperature until completely melted, and then cool to obtain Component B.

[0049] S3. Preparation of modified polypropylene injection molded parts: Mix 89% (by mass percentage) of Component A and 11% (by mass percentage) of Component B in proportion to obtain a modified polypropylene material. After the modified polypropylene material is injection molded, modified polypropylene injection molded parts are obtained. Then, samples of the same batch of modified polypropylene materials are taken for testing, and the surface tension and mechanical properties of the modified polypropylene materials are tested. The specific test process and test results are as follows: (1) Testing surface tension: Specimen preparation: Inject the modified polypropylene material into a 100 mm × 100 mm × 2 mm flat plate; Testing process: According to the standard ISO 8296, using the contact angle method, use a Dataphysics OCA20 contact angle meter to measure the contact angles of deionized water (polar liquid) and diiodomethane (non-polar liquid) on the surface of the specimen, and calculate the surface tension through the Owens-Wendt equation. After detection and calculation, the average surface tension of the modified polypropylene material prepared by the present invention is 49.5 mN / m.

[0050] (2) Testing mechanical properties: Tensile property testing process: According to the standard ISO 527-2, inject the modified polypropylene material into a Type 1A dumbbell specimen, with a tensile rate of 50 mm / min, and measure the elongation at break and tensile strength. After detection, the average elongation at break of the modified polypropylene material prepared by the present invention is 220%, and the average tensile strength is 29.9 MPa.

[0051] Impact property testing process: According to the standard ISO 180, inject the modified polypropylene material into a notched specimen of 80 mm × 10 mm × 4 mm, and measure the cantilever beam impact strength at 23 °C and -30 °C. After detection, the average cantilever beam impact strength (23 °C) of the modified polypropylene material prepared by the present invention is 34.1 KJ / m 2, the average Izod impact strength (-30 °C) is 12.4 KJ / m 2 .

[0052] S4. Produce suede automotive interior parts: Roll coat a 50-μm waterborne polyurethane coating adhesive (grade: AH-0203DB) on the surface of the modified polypropylene injection molded parts. After the roll coating is completed, lay suede material in the coated area. After the laying is completed, let it stand at room temperature for 24 h until the waterborne polyurethane coating adhesive is completely cured. Then, use a hot press to carry out pressure holding for 20 s at 80 °C and 0.5 MPa. After the pressure holding is completed, after cooling, flash trimming, and surface cleaning, suede automotive interior parts are obtained. Then, sample and test the suede automotive interior parts produced in the same batch, and test the bonding performance between the suede material and the modified polypropylene injection molded parts in the suede automotive interior parts. The specific test process and test results are as follows: Test process: According to standard GB / T 2791-1995, use 180° peel strength test, peel the suede automotive interior parts at a rate of 300 mm / min, record the average peel strength. After testing, the average peel strength of the suede automotive interior parts produced by the present invention is 18.7 N / 25mm.

[0053] Comparative Example 1 Comparative Example 1 is the control group of Example 5. Compared with Example 5, in Comparative Example 1, component B is completely removed, and only component A (polypropylene, talcum powder, POE, white carbon black, EVA210, antioxidant) is used, that is, 100% component A. The remaining raw materials, raw material dosages, preparation steps, and test processes are all kept the same as those in Example 5. The test results of each item are shown in Table 1 as follows: Table 1 Test Results Analysis: The core-shell microsphere foaming agent of component B and the polyethylene wax migration process are the core factors for improving the surface tension (+56.9%) and peel strength (+208%), and at the same time improve the impact performance through the pore structure.

[0054] Comparative Example 2 Comparative Example 2 is the control group of Example 5. Compared with Example 5, in Comparative Example 2, the acrylate microsphere foaming agent is replaced with azodicarbonamide foaming agent. The remaining raw materials, raw material dosages, preparation steps, and test processes are all kept the same as those in Example 5. The test results of each item are shown in Table 2 as follows: Table 2 Test Results Analysis: The three-layer structure of the core-shell microsphere (foaming + polar coating + grafting) is irreplaceable for improving the surface tension (+28.6%) and peel strength (+66.1%), and avoids the negative impact of ordinary foaming agents on the mechanical properties.

[0055] Comparative Example 3 Comparative Example 3 is the control group of Example 5. Compared with Example 5, precipitated silica in Component A of Comparative Example 3 was removed, and the remaining raw materials, raw material dosages, preparation steps, and testing processes were all kept the same as those in Example 5. The test results of each item are shown in Table 3 as follows: Table 3 Test Results Analysis: The synergistic dispersion system of precipitated silica and polar polymers is the key to maintaining high surface tension (+7.8%), peel strength (+24.8%), and mechanical properties (tensile strength +14.6%).

[0056] Comparative Example 4 Comparative Example 4 is the control group of Example 5. Compared with Example 5, ethylene-vinyl acetate copolymer (grade: EVA210) in Component A of Comparative Example 4 was removed, and the remaining raw materials, raw material dosages, preparation steps, and testing processes were all kept the same as those in Example 5. The test results of each item are shown in Table 4 as follows: Table 4 Test Results Analysis: Polar polymer (EVA210) is a necessary condition for improving surface tension (+39.0%) and peel strength (+114.6%), and its hydrogen bond interaction with precipitated silica is crucial for optimizing mechanical properties.

[0057] It should be noted that in this article, terms such as "including", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or elements inherent to such process, method, article or device.

[0058] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. High surface tension modified polypropylene material, characterized in that, It consists of raw materials in the following mass percentages: 88% - 89% of Component A; 11% - 12% of Component B; The said Component A includes raw materials in the following mass parts: 50 - 90 parts of polypropylene, 5 - 30 parts of talcum powder, 5 - 15 parts of polyolefin elastomer, 2 - 5 parts of precipitated silica, 2 - 5 parts of polar polymer, 0.2 - 0.8 parts of antioxidant; The said Component B is formed by melting and mixing acrylate microsphere foaming agent and polyethylene wax in a mass ratio of 1:

1.

2. The high surface tension modified polypropylene material according to claim 1, characterized in that The said polar polymer is one of ethylene - ethyl acrylate copolymer, ethylene - vinyl acetate copolymer, and chlorinated polyethylene.

3. The high surface tension modified polypropylene material according to claim 1, wherein The said antioxidant is formed by mixing antioxidant 1010 and antioxidant 168 in a mass ratio of 1:

1.

4. The high surface tension modified polypropylene material according to claim 1, characterized in that The said acrylate microsphere foaming agent is prepared by the following steps: A1. Add polyvinyl alcohol to deionized water, heat up to 60°C and stir to dissolve for 30 min to form an aqueous phase; mix methyl methacrylate, divinylbenzene, azodicarbonamide, and benzoyl peroxide evenly, and ultrasonically disperse for 10 min to form an oil phase; pour the oil phase into the aqueous phase, emulsify at a speed of 800 rpm to form droplets with a particle size of 20 - 50 μm, heat up to 75 - 80°C and react for 3 - 4 h, then rise to 85 - 90°C for curing for 2 - 3 h to obtain a reaction solution. After the reaction solution is cooled, centrifuged, washed, and vacuum dried, core - layer microspheres are obtained; A2. Dissolve ethylene - ethyl acrylate in xylene, stir at 70 - 80°C for 1 - 2 h to obtain an ethylene - ethyl acrylate solution; then immerse the core - layer microspheres in the ethylene - ethyl acrylate solution, maintain a vacuum of - 0.08 MPa for 20 - 30 min, then place them in an oven at 50°C and dry for 2 h, and then heat up to 102 - 105°C for heat treatment for 1 - 2 h to obtain intermediate - layer microspheres; A3. Dry - mix ethylene - vinyl acetate copolymer grafted maleic anhydride, dibutyltin dilaurate with the intermediate - layer microspheres to obtain a mixture, and use a twin - screw extruder to extrude and granulate the mixture to obtain the acrylate microsphere foaming agent.

5. The high surface tension modified polypropylene material according to claim 4, wherein The mass - part usage ratio of deionized water, polyvinyl alcohol, methyl methacrylate, divinylbenzene, azodicarbonamide, and benzoyl peroxide in A1 is 500:3 - 5:100:8 - 10:22 - 25:0.8 - 1.

0.

6. The high surface tension modified polypropylene material according to claim 4, characterized in that, The mass - part usage ratio of ethylene - ethyl acrylate, xylene, and core - layer microspheres in A2 is 30 - 40:150:

100.

7. The high surface tension modified polypropylene material according to claim 4, characterized in that, The mass - part usage ratio of ethylene - vinyl acetate copolymer grafted maleic anhydride, dibutyltin dilaurate, and intermediate - layer microspheres in A3 is 20:0.3 - 0.5:

100.

8. The high surface tension modified polypropylene material according to claim 4, characterized in that, The parameter settings of the twin - screw extruder in A3: Set temperature: Zone 1 120 - 125°C, Zone 2 140 - 150°C, Zone 3 155 - 160°C; Set speed: 80 - 100 rpm.

9. Use of the high surface tension modified polypropylene material according to any one of claims 1 to 8, characterized in that, It includes the following steps: S1. Weigh each raw material according to mass parts, mix evenly, and then place it in a twin - screw extruder, and extrude and granulate at a temperature of 180 - 230°C to obtain Component A; S2. Mix the acrylate microsphere foaming agent and polyethylene wax in a mass ratio of 1:1, heat to 90-95 °C, stir at a constant temperature until completely melted, and then cool to obtain Component B; S3. After mixing Component A and Component B according to the mass percentage, a modified polypropylene material is obtained. The modified polypropylene material is then injection molded to obtain a modified polypropylene injection molded part; S4. Roll coat a 40-50 μm waterborne polyurethane coating adhesive on the surface of the modified polypropylene injection molded part. After the roll coating is completed, lay suede material in the coated area. After the laying is completed, let it stand at room temperature for 24 h, and then use a hot press to carry out pressure holding at 60-80 °C and 0.3-0.5 MPa for 10-20 s. After the pressure holding is completed, after cooling, flash trimming, and surface cleaning, a suede automotive interior part is obtained.

10. Use of the high surface tension modified polypropylene material according to claim 9, characterized in that, The waterborne polyurethane coating adhesive has the grade of AH-0203DB.

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