High surface tension modified polypropylene material and its application

Abstract

The present invention discloses a high-surface-tension modified polypropylene material and its application, belonging to the technical field of modified polypropylene materials. The present invention provides a high-surface-tension modified polypropylene material composed of component A and component B. Component A comprises the following raw materials in parts by weight: 50-90 parts polypropylene, 5-30 parts talc, 5-15 parts polyolefin elastomer, 2-5 parts precipitated silica, 2-5 parts polar polymer, and 0.2-0.8 parts antioxidant. Component B is melt-blended with an acrylic microsphere foaming agent and polyethylene wax in a 1:1 mass ratio. This invention addresses the challenges of poor compatibility between polypropylene substrates and polar adhesives, the high cost and inefficiency of plasma treatment processes, and the reduced mechanical properties caused by single polar additives in automotive interior applications. Through innovative material formulation design and process optimization, a modified polypropylene material with high surface tension, long-lasting adhesion, and excellent mechanical properties is proposed.

Description

Technical Field

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

[0002] Automotive interior components are increasingly being designed with injection-molded polypropylene (PP) substrates covered with suede or leather. However, PP has low surface tension due to its non-polar properties and poor compatibility with polar adhesives, requiring plasma treatment to enhance bonding strength.

[0003] Existing plasma treatment processes are costly and inefficient. Surface tension decays over time after treatment, leading to delamination of the coated parts over time. While simply adding polar additives can increase surface tension, it significantly reduces material toughness.

[0004] There is an urgent need to develop a modified PP material with high surface tension, long-lasting adhesion and mechanical balance to replace plasma treatment and meet the industrialization needs of automotive interiors. Summary of the Invention

[0005] The object of the present invention is to provide a high surface tension modified polypropylene material and application thereof, so as to solve the problems in the background technology.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] High surface tension modified polypropylene material is composed of the following raw materials in percentage by weight:

[0008] 88%~89% component A;

[0009] 11%~12% component B;

[0010] The component A comprises the following raw materials in parts by weight:

[0011] Polypropylene 50-90 parts, talc 5-30 parts, polyolefin elastomer 5-15 parts, precipitated silica 2-5 parts, polar polymer 2-5 parts, antioxidant 0.2-0.8 parts;

[0012] The component B is prepared by melt-mixing an acrylic microsphere foaming agent and polyethylene wax in a mass ratio of 1:1.

[0013] Furthermore, the polar polymer is one of ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, and chlorinated polyethylene.

[0014] Furthermore, the antioxidant is prepared by mixing antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0015] Furthermore, the acrylic ester microsphere foaming agent is prepared by the following steps:

[0016] A1. Add polyvinyl alcohol to deionized water, heat to 60°C, and stir to dissolve for 30 minutes to form an aqueous phase; mix methyl methacrylate, divinylbenzene, azodicarbonamide, and benzoyl peroxide evenly, and ultrasonically disperse for 10 minutes to form an oil phase; pour the oil phase into the aqueous phase, emulsify at 800 rpm to form droplets with a particle size of 20-50 μm, heat to 75-80°C, react for 3-4 hours, and then heat to 85-90°C and mature for 2-3 hours to obtain a reaction solution. Cool the reaction solution, centrifuge, wash, and vacuum dry to obtain core layer microspheres;

[0017] A2. Dissolve ethylene-ethyl acrylate in xylene and stir at 70-80°C for 1-2 hours to obtain an ethylene-ethyl acrylate solution. Then, immerse the core layer microspheres in the ethylene-ethyl acrylate solution and maintain a vacuum of -0.08 MPa for 20-30 minutes. Then, dry them at 50°C for 2 hours and heat-treat them at 102-105°C for 1-2 hours to obtain the intermediate layer microspheres.

[0018] A3. Dry-mixing ethylene-vinyl acetate copolymer grafted with maleic anhydride, dibutyltin dilaurate and the intermediate layer microspheres to obtain a mixture, and extruding and granulating the mixture using a twin-screw extruder to obtain an acrylic microsphere foaming agent.

[0019] Furthermore, the mass 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.

[0020] Furthermore, the mass ratio of ethylene-ethyl acrylate, xylene, and core layer microspheres in A2 is 30-40:150:100.

[0021] Furthermore, the mass ratio of the ethylene-vinyl acetate copolymer grafted maleic anhydride, dibutyltin dilaurate, and intermediate layer microspheres in A3 is 20:0.3 to 0.5:100.

[0022] Furthermore, the parameters of the twin-screw extruder described in A3 are set as follows: set temperature: zone 1 120-125°C, zone 2 140-150°C, zone 3 155-160°C; set speed: 80-100 rpm.

[0023] Furthermore, the application of the high surface tension modified polypropylene material comprises the following steps:

[0024] S1. Weigh the raw materials according to their mass, mix them evenly, and then place them in a twin-screw extruder. Extrusion and granulation are performed at a temperature of 180-230° C. to obtain component A.

[0025] S2. Mixing an acrylic microsphere foaming agent and polyethylene wax in a mass ratio of 1:1, heating to 90-95° C., stirring at a constant temperature until completely melted, and cooling to obtain component B;

[0026] S3, mixing component A and component B according to mass percentage to obtain a modified polypropylene material, and then injection molding the modified polypropylene material to obtain a modified polypropylene injection molded part;

[0027] S4. Roll-coat 40-50 μm of water-based polyurethane coating glue on the surface of the modified polypropylene injection molded part. After the roller coating is completed, lay suede material on the glue-coated area. After laying, let it stand at room temperature for 24 hours, and then use a hot press to maintain pressure for 10-20 seconds at 60-80°C and 0.3-0.5 MPa. After the pressure maintenance is completed, cool it, trim the overflow edge, and clean the surface to obtain suede automotive interior parts.

[0028] Furthermore, the brand of the water-based polyurethane coating adhesive is AH-0203DB.

[0029] Beneficial effects of the present invention:

[0030] This invention addresses the challenges faced by polypropylene (PP) substrates in automotive interior applications, including poor compatibility with polar adhesives, high plasma treatment costs and limited timeliness, and reduced mechanical properties due to single polar additives. Through innovative material formulation design and process optimization, a modified polypropylene material with high surface tension, long-lasting adhesion, and excellent mechanical properties has been developed. Its beneficial effects and innovative breakthroughs are primarily reflected in the following aspects:

[0031] 1. Multi-dimensional synergistic effect of core-shell structure microsphere foaming agent:

[0032] Technological breakthrough: The acrylic microsphere foaming agent in component B adopts a three-layer composite structure design of "core layer foaming-middle layer volume expansion-shell layer polar grafting", achieving dual optimization of surface polarity enhancement and internal toughness of the material.

[0033] (1) Core layer microspheres (methyl methacrylate-based): The azodicarbonamide foaming agent expands under heat during processing, forming micron-sized pores (20-50 μm) on the surface of the material, significantly increasing the specific surface area and providing mechanical anchoring points for subsequent bonding.

[0034] (2) Intermediate layer (ethylene-ethyl acrylate coating): Through vacuum impregnation and melt coating processes, the polar chain segment (ethyl acrylate) penetrates into the pores of the microspheres to form a continuous polar interface, enhancing the compatibility with the polypropylene matrix in component A (peel strength is increased to 17.5-19.1 N / 25mm).

[0035] (3) Shell (maleic anhydride grafted EVA): The grafted carboxylic acid groups migrate directionally to the surface of the material during the injection molding process, forming stable polar active sites (surface tension reaches 48.2-51.0 mN / m), and suppress the decay of surface polarity through chemical bonding, solving the problem of poor timeliness of traditional plasma treatment.

[0036] In traditional technology, foaming agents are only used to reduce density or improve processing fluidity. However, the microsphere foaming agent of the present invention integrates the triple functions of "physical anchoring", "chemical polarity" and "interface volume expansion" for the first time through structural design, achieving simultaneous breakthroughs in surface tension and bonding durability without sacrificing mechanical properties (elongation at break 215% to 240%).

[0037] 2. Coordinated dispersion system of polar polymer and inorganic filler:

[0038] Technological breakthrough: A composite system of precipitated silica (2 to 5 parts) and polar polymers (EAA / EVA / CPE) is introduced into component A. The polar polymer is used to coat the surface of the silica to construct a "polar-inorganic" network structure.

[0039] (1) Nano-dispersion effect of silica: The specific surface area of ​​silica is as high as 200-400 m² / g. The surface silanol groups form hydrogen bonds with the carboxyl / ester groups of polar polymers, inhibiting the agglomeration of polar additives and ensuring that the polar groups are evenly distributed in the matrix.

[0040] (2) Mechanical property compensation mechanism: The rigid particles of silica and polyolefin elastomer (POE8150) form a "rigid-flexible" interpenetrating network, which improves the tensile strength (28.4-30.7 MPa) while absorbing the impact energy through the elastomer (the impact strength at -30°C is still 10.2-13.5 KJ / m²), breaking the bottleneck of the sudden drop in toughness of traditional polar modified PP.

[0041] In traditional technologies, the addition of polar additives and inorganic fillers often leads to phase separation (such as the interface defects between CPE and talc). However, the present invention achieves nano-scale dispersion and interface strengthening through pre-compounding of polar polymers and silica, so that the material can achieve synergistic optimization in the three dimensions of polarity, strength and toughness.

[0042] 3. Melt mixing process and surface migration control of component B

[0043] Technological breakthrough: Component B (acrylate microsphere foaming agent + polyethylene wax) adopts a melt-mixing and then cooling granulation process, and utilizes the migration characteristics of polyethylene wax to guide the microspheres to be distributed in a directional manner on the surface of the material during the injection molding process.

[0044] (1) Migration kinetics control: Polyethylene wax (melting point 90-95°C) melts at the high temperature of injection molding and carries the microspheres to the low-temperature area (mold surface), forming a gradient distribution structure and maximizing the polar function of the microspheres (surface tension is increased to 51 mN / m, close to the PET level).

[0045] (2) Processing performance optimization: Polyethylene wax acts as a lubricant to reduce melt viscosity and avoid processing difficulties caused by high talc filling without affecting the surface finish of the final product.

[0046] In traditional modification processes, it is difficult to achieve both uniform dispersion and functional distribution of polar components. However, the present invention achieves selective enrichment of functional microspheres through the directional migration design of component B without the need for complex surface treatment, significantly reducing production costs and achieving high process stability.

[0047] 4. Environmental protection throughout the entire life cycle and industrial adaptability

[0048] Technological breakthrough: Direct bonding of a water-based polyurethane adhesive (AH-0203DB) and modified PP avoids VOC emissions associated with traditional solvent-based adhesives while ensuring bonding reliability through the material's high surface tension (peel strength reaches 19.1 N / 25mm, exceeding the industry standard of 12 N / 25mm).

[0049] In summary, the core innovation of this invention lies in the collaborative innovation of core-shell microsphere structure design, polar-inorganic composite dispersion system, and component-directed migration process. This overcomes the technical bottlenecks of traditional PP modification technology, namely, "high polarity necessarily compromises toughness" and "surface treatment relies on external processes," thereby achieving a balance between spontaneous surface functionalization and mechanical properties. This technical approach has significant industrial value in the automotive interior field and is expected to expand into high-end applications such as home appliances and electronic packaging, which have stringent requirements for surface adhesion and mechanical properties. DETAILED DESCRIPTION

[0050] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0051] Example 1

[0052] Preparation of acrylic microsphere foaming agent:

[0053] A1. Preparation of core-layer microspheres: 500 parts (by weight, the same below) of deionized water and 3 parts of polyvinyl alcohol (brand: PVA1788) were added to a reaction kettle, heated to 60°C, and stirred for 30 minutes to form an aqueous phase. 100 parts of methyl methacrylate, 8 parts of divinylbenzene, 22 parts of azodicarbonamide, and 0.8 parts of benzoyl peroxide were mixed uniformly and ultrasonically dispersed for 10 minutes (power 300W) to form an oil phase. The oil phase was poured into the aqueous phase and emulsified at 800 rpm to form droplets with a particle size of 50 μm. The reaction mixture was heated to 75°C for 3 hours, and then heated to 85°C for 2 hours to obtain a reaction solution. The reaction solution was then cooled to 40°C, centrifuged, washed three times with 50°C hot water, and vacuum-dried to obtain core-layer microspheres.

[0054] A2. Intermediate layer coating: 30 parts of ethylene ethyl acrylate (brand: Arkema 5500, France) were dissolved in 150 parts of xylene and stirred at 70°C for 1 hour to obtain an ethylene ethyl acrylate solution. 100 parts of core layer microspheres were then immersed in the ethylene ethyl acrylate solution and maintained under a vacuum of -0.08 MPa for 20 minutes to allow the solution to penetrate the pores of the microspheres. The microspheres were then dried at 50°C for 2 hours to remove the solvent. The microspheres were then heated to 102°C for 1 hour to melt the ethylene ethyl acrylate and coat the surface, thereby obtaining intermediate layer microspheres.

[0055] A3. Shell grafting: 20 parts of ethylene-vinyl acetate copolymer grafted with maleic anhydride (brand: Dow 39E660), 0.3 parts of dibutyltin dilaurate, and 100 parts of intermediate layer microspheres were dry-blended to obtain a mixture. The mixture was extruded and granulated using a twin-screw extruder with set temperatures of 120°C in zone 1, 140°C in zone 2, and 155°C in zone 3, and a rotation speed of 80 rpm to obtain an acrylic microsphere foaming agent.

[0056] Example 2

[0057] Preparation of acrylic microsphere foaming agent:

[0058] A1. Preparation of core-layer microspheres: 500 parts (by weight, the same below) of deionized water and 5 parts of polyvinyl alcohol (brand: PVA1788) were added to a reactor, heated to 60°C, and stirred for 30 minutes to form an aqueous phase. 100 parts of methyl methacrylate, 9 parts of divinylbenzene, 24 parts of azodicarbonamide, and 1.0 part of benzoyl peroxide were mixed uniformly and ultrasonically dispersed for 10 minutes (power 300W) to form an oil phase. The oil phase was poured into the aqueous phase and emulsified at 800 rpm to form droplets with a particle size of 20 μm. The reaction mixture was heated to 75°C for 4 hours, and then heated to 85°C for aging for 3 hours to obtain a reaction solution. The reaction solution was then cooled to 40°C, centrifuged, washed three times with 50°C hot water, and vacuum-dried to obtain core-layer microspheres.

[0059] A2. Intermediate layer coating: 35 parts of ethylene ethyl acrylate (brand: Arkema 5500, France) were dissolved in 150 parts of xylene and stirred at 75°C for 2 hours to obtain an ethylene ethyl acrylate solution. 100 parts of core layer microspheres were then immersed in the ethylene ethyl acrylate solution and maintained under a vacuum of -0.08 MPa for 30 minutes to allow the solution to penetrate the pores of the microspheres. The microspheres were then dried at 50°C for 2 hours to remove the solvent. The microspheres were then heated to 104°C for 2 hours to melt the ethylene ethyl acrylate and coat the surface, thereby obtaining intermediate layer microspheres.

[0060] A3. Shell grafting: 20 parts of ethylene-vinyl acetate copolymer grafted with maleic anhydride (brand: Dow 39E660), 0.5 parts of dibutyltin dilaurate, and 100 parts of intermediate layer microspheres were dry-blended to obtain a mixture. The mixture was extruded and granulated using a twin-screw extruder with set temperatures of 125°C in zone 1, 145°C in zone 2, and 155°C in zone 3, and a rotation speed of 100 rpm to obtain an acrylic microsphere foaming agent.

[0061] Example 3

[0062] Preparation of acrylic microsphere foaming agent:

[0063] A1. Preparation of core-layer microspheres: 500 parts (by weight, the same below) of deionized water and 5 parts of polyvinyl alcohol (brand: PVA1788) were added to a reactor, heated to 60°C, and stirred for 30 minutes to dissolve to form an aqueous phase. 100 parts of methyl methacrylate, 10 parts of divinylbenzene, 25 parts of azodicarbonamide, and 1 part of benzoyl peroxide were mixed uniformly and ultrasonically dispersed for 10 minutes (power 300W) to form an oil phase. The oil phase was poured into the aqueous phase and emulsified at 800 rpm to form droplets with a particle size of 40 μm. The reaction mixture was heated to 80°C for 4 hours, and then heated to 90°C for aging for 3 hours to obtain a reaction solution. The reaction solution was then cooled to 50°C, centrifuged, washed three times with 50°C hot water, and vacuum-dried to obtain core-layer microspheres.

[0064] A2. Intermediate layer coating: 40 parts of ethylene ethyl acrylate (brand: Arkema 5500, France) were dissolved in 150 parts of xylene and stirred at 80°C for 2 hours to obtain an ethylene ethyl acrylate solution. 100 parts of core layer microspheres were then immersed in the ethylene ethyl acrylate solution and maintained under a vacuum of -0.08 MPa for 30 minutes to allow the solution to penetrate the pores of the microspheres. The microspheres were then dried at 50°C for 2 hours to remove the solvent. The microspheres were then heated to 105°C for 2 hours to melt the ethylene ethyl acrylate and coat the surface, thereby obtaining intermediate layer microspheres.

[0065] A3. Shell grafting: 20 parts of ethylene-vinyl acetate copolymer grafted with maleic anhydride (brand: Dow 39E660), 0.5 parts of dibutyltin dilaurate, and 100 parts of intermediate layer microspheres were dry-blended to obtain a mixture. The mixture was extruded and granulated using a twin-screw extruder with set temperatures of 125°C in zone 1, 150°C in zone 2, and 160°C in zone 3, and a rotation speed of 100 rpm to obtain an acrylic microsphere foaming agent.

[0066] Example 4

[0067] The production of suede automotive interior parts includes the following steps:

[0068] S1. Prepare component A: First, component A includes the following raw materials in parts by mass: 50 parts of polypropylene (brand: K4912), 5 parts of talc, 5 parts of polyolefin elastomer (brand: POE8150), 2 parts of precipitated silica, 2 parts of ethylene-ethyl acrylate copolymer (brand: EAA378), and 0.2 parts of antioxidant, wherein the antioxidant is prepared by mixing antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1. Weigh each raw material according to the above-mentioned parts by mass, mix them evenly, and then place them in a twin-screw extruder and extrude and granulate them at a temperature of 180°C to obtain component A.

[0069] S2. Prepare component B: Mix the acrylic 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 cool to obtain component B.

[0070] S3. Preparation of modified polypropylene injection molded parts: 89% (mass percentage) of component A and 11% (mass percentage) of component B were mixed in proportion to obtain a modified polypropylene material. The modified polypropylene material was then injection molded to obtain modified polypropylene injection molded parts. Then, the same batch of modified polypropylene materials was sampled and tested to test the surface tension and mechanical properties of the modified polypropylene materials. The specific test process and test results are as follows:

[0071] (1) Test surface tension:

[0072] Sample preparation: The modified polypropylene material was injection molded into a 100 mm × 100 mm × 2 mm flat plate;

[0073] Testing process: According to standard ISO 8296, the contact angle method was used, using a Dataphysics OCA20 contact angle meter to measure the contact angles of deionized water (polar liquid) and diiodomethane (non-polar liquid) on the sample surface. The surface tension was calculated using the Owens-Wendt equation. After testing and calculation, the modified polypropylene material prepared by the present invention had an average surface tension of 48.2 mN / m.

[0074] (2) Test mechanical properties:

[0075] Tensile property testing process: According to standard ISO 527-2, the modified polypropylene material was injection molded into a 1A dumbbell specimen at a tensile rate of 50 mm / min, and the elongation at break and tensile strength were measured. The modified polypropylene material prepared by the present invention had an average elongation at break of 215% and an average tensile strength of 28.4 MPa.

[0076] Impact performance test process: According to the standard ISO 180, the modified polypropylene material was injection molded into 80 mm × 10 mm × 4 mm notched specimens, and the cantilever beam impact strength at 23°C and -30°C was measured. The average cantilever beam impact strength (23°C) of the modified polypropylene material prepared by the present invention was 32.8 kJ / m 2 The average Izod impact strength (-30°C) is 10.2 KJ / m 2 .

[0077] S4. Production of suede automotive interior parts: 40μm thick water-based polyurethane coating adhesive (brand: AH-0203DB) was roller-coated on the surface of modified polypropylene injection molded parts. After roller coating, suede material was laid on the coated area. After laying, the adhesive was left to stand at room temperature for 24 hours until the water-based polyurethane coating adhesive was completely cured. Then, a hot press was used to maintain pressure for 10 seconds at 60°C and 0.3MPa. After the pressure was maintained, the parts were cooled, the overflow edges were trimmed, and the surface was cleaned to obtain suede automotive interior parts. Then, suede automotive interior parts produced in the same batch were sampled and tested to 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:

[0078] Testing process: According to the standard GB / T 2791-1995, a 180° peel strength test was performed, and the suede automotive interior parts were peeled at a rate of 300 mm / min. The average peel strength was recorded. After testing, the average peel strength of the suede automotive interior parts produced by the present invention was 17.5 N / 25 mm.

[0079] Example 5

[0080] The production of suede automotive interior parts includes the following steps:

[0081] S1. Preparation of component A: First, component A includes the following raw materials in parts by mass: 80 parts of polypropylene (brand: K4912), 15 parts of talc, 10 parts of polyolefin elastomer (brand: POE8150), 4 parts of precipitated silica, 4 parts of ethylene-vinyl acetate copolymer (brand: EVA210), and 0.8 parts of antioxidant, wherein the antioxidant is prepared by mixing antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1. Weigh each raw material according to the above-mentioned parts by mass, mix them evenly, and then place them in a twin-screw extruder and extrude and granulate them at a temperature of 210°C to obtain component A.

[0082] S2. Prepare component B: Mix the acrylic microsphere foaming agent prepared in Example 2 and polyethylene wax in a mass ratio of 1:1, heat to 90° C., stir at a constant temperature until completely melted, and cool to obtain component B.

[0083] S3. Preparation of modified polypropylene injection molded parts: 88% (mass percentage) of component A and 12% (mass percentage) of component B were mixed in proportion to obtain a modified polypropylene material. The modified polypropylene material was then injection molded to obtain modified polypropylene injection molded parts. Then, the same batch of modified polypropylene materials was sampled and tested to test the surface tension and mechanical properties of the modified polypropylene materials. The specific test process and test results are as follows:

[0084] (1) Test surface tension:

[0085] Sample preparation: The modified polypropylene material was injection molded into a 100 mm × 100 mm × 2 mm flat plate;

[0086] Testing process: According to standard ISO 8296, the contact angle method was used, using a Dataphysics OCA20 contact angle meter to measure the contact angles of deionized water (polar liquid) and diiodomethane (non-polar liquid) on the sample surface. The surface tension was calculated using the Owens-Wendt equation. After testing and calculation, the modified polypropylene material prepared by the present invention had an average surface tension of 51.0 mN / m.

[0087] (2) Test mechanical properties:

[0088] Tensile property testing process: According to standard ISO 527-2, the modified polypropylene material was injection molded into a 1A dumbbell specimen at a tensile rate of 50 mm / min, and the elongation at break and tensile strength were measured. The modified polypropylene material prepared by the present invention had an average elongation at break of 240% and an average tensile strength of 30.7 MPa.

[0089] Impact performance test process: According to the standard ISO 180, the modified polypropylene material was injection molded into an 80 mm × 10 mm × 4 mm notched specimen, and the cantilever beam impact strength at 23°C and -30°C was measured. The average cantilever beam impact strength (23°C) of the modified polypropylene material prepared by the present invention was 35.1 kJ / m 2 The average Izod impact strength (-30℃) is 13.5 KJ / m 2 .

[0090] S4. Production of suede automotive interior parts: 50 μm of water-based polyurethane coating adhesive (brand: AH-0203DB) was roller-coated on the surface of modified polypropylene injection molded parts. After roller coating, suede material was laid on the coated area. After laying, the adhesive was left to stand at room temperature for 24 hours until the water-based polyurethane coating adhesive was completely cured. Then, a hot press was used to maintain pressure at 70°C and 0.5 MPa for 20 seconds. After the pressure was maintained, the parts were cooled, the overflow was trimmed, and the surface was cleaned to obtain suede automotive interior parts. Then, suede automotive interior parts produced in the same batch were sampled and tested to 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:

[0091] Testing process: According to the standard GB / T 2791-1995, a 180° peel strength test was performed, and the suede automotive interior parts were peeled at a rate of 300 mm / min. The average peel strength was recorded. After testing, the average peel strength of the suede automotive interior parts produced by the present invention was 19.1 N / 25 mm.

[0092] Example 6

[0093] The production of suede automotive interior parts includes the following steps:

[0094] S1. Prepare component A: First, component A includes the following raw materials in parts by mass: 90 parts of polypropylene (brand: K4912), 30 parts of talc, 15 parts of polyolefin elastomer (brand: POE8150), 5 parts of precipitated silica, 5 parts of chlorinated polyethylene (brand: CPE135A), and 0.8 parts of antioxidant, wherein the antioxidant is prepared by mixing antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1. Weigh each raw material according to the above-mentioned parts by mass, mix them evenly, and then place them in a twin-screw extruder and extrude and granulate them at a temperature of 230°C to obtain component A.

[0095] S2. Prepare component B: Mix the acrylic 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 cool to obtain component B.

[0096] S3. Preparation of modified polypropylene injection molded parts: 89% (mass percentage) of component A and 11% (mass percentage) of component B were mixed in proportion to obtain a modified polypropylene material. The modified polypropylene material was then injection molded to obtain modified polypropylene injection molded parts. Then, the same batch of modified polypropylene materials was sampled and tested to test the surface tension and mechanical properties of the modified polypropylene materials. The specific test process and test results are as follows:

[0097] (1) Test surface tension:

[0098] Sample preparation: The modified polypropylene material was injection molded into a 100 mm × 100 mm × 2 mm flat plate;

[0099] Testing process: According to standard ISO 8296, the contact angle method was used, using a Dataphysics OCA20 contact angle meter to measure the contact angles of deionized water (polar liquid) and diiodomethane (non-polar liquid) on the sample surface. The surface tension was calculated using the Owens-Wendt equation. After testing and calculation, the modified polypropylene material prepared by the present invention had an average surface tension of 49.5 mN / m.

[0100] (2) Test mechanical properties:

[0101] Tensile property testing process: According to standard ISO 527-2, the modified polypropylene material was injection molded into a 1A dumbbell specimen at a tensile rate of 50 mm / min, and the elongation at break and tensile strength were measured. The modified polypropylene material prepared by the present invention had an average elongation at break of 220% and an average tensile strength of 29.9 MPa.

[0102] Impact performance test process: According to the standard ISO 180, the modified polypropylene material was injection molded into an 80 mm × 10 mm × 4 mm notched specimen, and the cantilever beam impact strength at 23°C and -30°C was measured. The average cantilever beam impact strength (23°C) of the modified polypropylene material prepared by the present invention was 34.1 kJ / m 2 The average Izod impact strength (-30°C) is 12.4 KJ / m 2 .

[0103] S4. Production of suede automotive interior parts: 50 μm of water-based polyurethane coating adhesive (brand: AH-0203DB) was roller-coated on the surface of modified polypropylene injection molded parts. After roller coating, suede material was laid on the coated area. After laying, the adhesive was left to stand at room temperature for 24 hours until the water-based polyurethane coating adhesive was completely cured. Then, a hot press was used to maintain pressure at 80°C and 0.5 MPa for 20 seconds. After the pressure was maintained, the parts were cooled, the overflow was trimmed, and the surface was cleaned to obtain suede automotive interior parts. Then, suede automotive interior parts produced in the same batch were sampled and tested to 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:

[0104] Testing process: According to the standard GB / T 2791-1995, a 180° peel strength test was performed, and the suede automotive interior parts were peeled at a rate of 300 mm / min. The average peel strength was recorded. After testing, the average peel strength of the suede automotive interior parts produced by the present invention was 18.7 N / 25 mm.

[0105] Comparative Example 1

[0106] Comparative Example 1 is the control group of Example 5. Relative to Example 5, in Comparative Example 1, component B is completely removed and only component A (polypropylene, talc, POE, white carbon black, EVA210, antioxidant) is used, that is, 100% component A. The remaining raw materials, raw material amounts, preparation steps, and testing processes are all the same as those in Example 5. The final test results of each item are shown in Table 1:

[0107] Table 1 Test results

[0108]

[0109] Analysis: The core-shell microsphere foaming agent and polyethylene wax migration process in component B are the key factors in improving surface tension (+56.9%) and peel strength (+208%), while also improving impact performance through the pore structure.

[0110] Comparative Example 2

[0111] Comparative Example 2 is the control group of Example 5. Relative to Example 5, Comparative Example 2 replaces the acrylic ester microsphere foaming agent with an azodicarbonamide foaming agent. The remaining raw materials, raw material amounts, preparation steps, and testing processes are the same as those in Example 5. The final test results of each item are shown in Table 2:

[0112] Table 2 Test results

[0113]

[0114] Analysis: The three-layer structure of core-shell microspheres (foaming + polar coating + grafting) is irreplaceable in improving surface tension (+28.6%) and peel strength (+66.1%), and avoids the negative impact of ordinary foaming agents on mechanical properties.

[0115] Comparative Example 3

[0116] Comparative Example 3 is the control group of Example 5. Compared with Example 5, Comparative Example 3 eliminates the precipitated silica in component A. The remaining raw materials, raw material amounts, preparation steps, and testing processes remain the same as those in Example 5. The final test results of each item are shown in Table 3:

[0117] Table 3 Test results

[0118]

[0119] Analysis: The synergistic dispersion system of silica and polar polymer is the key to maintaining high surface tension (+7.8%), peel strength (+24.8%) and mechanical properties (tensile strength +14.6%).

[0120] Comparative Example 4

[0121] Comparative Example 4 is the control group of Example 5. Compared with Example 5, Comparative Example 4 eliminates the ethylene-vinyl acetate copolymer (brand: EVA210) in component A. The remaining raw materials, raw material amounts, preparation steps, and testing processes are the same as those in Example 5. The final test results of each item are shown in Table 4:

[0122] Table 4 Test results

[0123]

[0124] Analysis: Polar polymer (EVA210) is necessary for improving surface tension (+39.0%) and peel strength (+114.6%), and its hydrogen bonding with silica is crucial for optimizing mechanical properties.

[0125] It should be noted that, in this document, terms such as "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements that are inherent to such process, method, article or apparatus.

[0126] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. High surface tension modified polypropylene material, characterized in that: It is composed of the following raw materials in percentage by mass: 88%~89% component A; 11%~12% component B; The component A comprises the following raw materials in parts by weight: Polypropylene 50-90 parts, talc 5-30 parts, polyolefin elastomer 5-15 parts, precipitated silica 2-5 parts, polar polymer 2-5 parts, antioxidant 0.2-0.8 parts; Component B is prepared by melt-mixing an acrylic microsphere foaming agent and polyethylene wax in a mass ratio of 1:1; The acrylate microsphere foaming agent is prepared by the following steps: A1. Add polyvinyl alcohol to deionized water, heat to 60°C, and stir to dissolve for 30 minutes to form an aqueous phase; mix methyl methacrylate, divinylbenzene, azodicarbonamide, and benzoyl peroxide evenly, and ultrasonically disperse for 10 minutes to form an oil phase; pour the oil phase into the aqueous phase, emulsify at 800 rpm to form droplets with a particle size of 20-50 μm, heat to 75-80°C, react for 3-4 hours, and then heat to 85-90°C and mature for 2-3 hours to obtain a reaction solution. The reaction solution is cooled, centrifuged, washed, and vacuum-dried to obtain core layer microspheres; A2. Dissolve ethylene-ethyl acrylate in xylene and stir at 70-80°C for 1-2 hours to obtain an ethylene-ethyl acrylate solution. Then, immerse the core layer microspheres in the ethylene-ethyl acrylate solution and maintain a vacuum of -0.08 MPa for 20-30 minutes. Then, dry them at 50°C for 2 hours and heat-treat them at 102-105°C for 1-2 hours to obtain the intermediate layer microspheres. A3. Dry-mixing ethylene-vinyl acetate copolymer grafted with maleic anhydride, dibutyltin dilaurate and the intermediate layer microspheres to obtain a mixture, and extruding and granulating the mixture using a twin-screw extruder to obtain an acrylic microsphere foaming agent.

2. The high surface tension modified polypropylene material according to claim 1, characterized in that: The 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, characterized in that: The antioxidant is prepared 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 mass 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.

5. The high surface tension modified polypropylene material according to claim 1, characterized in that: The mass ratio of ethylene-ethyl acrylate, xylene and core layer microspheres in A2 is 30-40:150:

100.

6. The high surface tension modified polypropylene material according to claim 1, characterized in that: The mass ratio of the ethylene-vinyl acetate copolymer grafted maleic anhydride, dibutyltin dilaurate, and intermediate layer microspheres in A3 is 20:0.3 to 0.5:

100.

7. The high surface tension modified polypropylene material according to claim 1, characterized in that: The parameters of the twin-screw extruder described in A3 are as follows: set temperature: zone 1 120-125°C, zone 2 140-150°C, zone 3 155-160°C; set speed: 80-100 rpm.

8. Use of the high surface tension modified polypropylene material according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Weigh the raw materials according to their mass, mix them evenly, and then place them in a twin-screw extruder. Extrusion and granulation are performed at a temperature of 180-230° C. to obtain component A. S2. Mixing an acrylic microsphere foaming agent and polyethylene wax in a mass ratio of 1:1, heating to 90-95° C., stirring at a constant temperature until completely melted, and cooling to obtain component B; S3, mixing component A and component B according to mass percentage to obtain a modified polypropylene material, and then injection molding the modified polypropylene material to obtain a modified polypropylene injection molded part; S4. Roll-coat 40-50 μm of water-based polyurethane coating glue on the surface of the modified polypropylene injection molded part. After the roller coating is completed, lay suede material on the glue-coated area. After laying, let it stand at room temperature for 24 hours, and then use a hot press to maintain pressure for 10-20 seconds at 60-80°C and 0.3-0.5 MPa. After the pressure maintenance is completed, cool it, trim the overflow edge, and clean the surface to obtain suede automotive interior parts.

9. The use of the high surface tension modified polypropylene material according to claim 8, characterized in that: The brand of the water-based polyurethane coating adhesive is AH-0203DB.

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