PP (polypropylene) plastic for automotive trim and preparation method of PP plastic

Abstract

The invention discloses PP (polypropylene) plastic for automotive trim, which is prepared from the following raw materials in parts by weight: 90 to 100 parts of polypropylene, 8 to 12 parts of POE (polyolefin elastomer), 20 to 25 parts of modified talcum powder, 5 to 8 parts of compatilizer, 0.7 to 1.1 parts of lubricant and 0.4 to 0.7 part of heat stabilizer, according to the modified talcum powder, talcum powder is adopted as a raw material, ZnO / TiO2 is introduced to the talcum powder through a hydrothermal method, and then 5-amino-2-mercaptobenzimidazole and 1-(4, 6-diamino-1, 3, 5-triazine-2-yl) guanidine are sequentially introduced in a chemical bond mode. The PP plastic has excellent ultraviolet aging resistance, lasting antibacterial property, good dimensional stability and excellent mechanical property, can meet the comprehensive requirements of automotive interior materials on weather resistance, antibacterial property, dimensional stability, toughness and other properties, and has wide application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to a PP plastic for automobile interior decoration and a preparation method thereof. Background Art

[0002] Polypropylene (PP) is widely used in various aspects such as automobiles, household appliances, daily necessities manufacturing, and industrial production due to its low density, high cost performance, easy processing, excellent comprehensive mechanical properties, and strong chemical corrosion resistance. At the same time, in order to make it meet more complex usage conditions, higher requirements have also been put forward for the comprehensive performance of polypropylene products.

[0003] The usage amount of PP materials in automobiles accounts for about 46% of all polymer materials. The main reasons for the large usage amount of PP materials are as follows: PP resin has a low density, good heat resistance, high strength, high hardness, good insulation, and excellent acid and alkali corrosion resistance. The propylene monomer used to synthesize PP resin can be obtained through processes such as refinery catalysis and hydrocarbon cracking, and the manufacturing process is simple and the manufacturing cost is low. PP resin also has obvious disadvantages: large surface tension, poor paint adhesion; brittle at low temperature; poor heat aging and light aging resistance; poor flame retardant performance; relatively large linear expansion coefficient and large shrinkage rate of the material. In current technologies, the antibacterial, anti-aging performance and mechanical properties of most polypropylene materials applied to automobile interiors are not ideal.

[0004] To improve the light aging and heat aging performance of polypropylene materials, a large amount of heat stabilizers and light stabilizers are usually added during the production process of polypropylene materials. However, polypropylene itself is a non-polar material, while heat stabilizers and light stabilizers are mostly polar small molecule substances. Excessive addition of additives will cause a large amount of precipitation of additives due to compatibility problems, and at the same time lead to a decrease in the mechanical properties of the material.

[0005] Chinese patent application CN110016182A discloses an aging-resistant precipitation long glass fiber reinforced polypropylene material and a preparation method thereof, wherein the polypropylene material comprises the following components in percentage by total mass of the polypropylene material: 30-92wt.% of polypropylene, 5-60wt.% of long glass fiber, 0-5wt.% of compatibilizer, 1-3wt.% of masterbatch, 0.2-0.8wt.% of thermal oxygen stabilizer, 0.1-0.5wt.% of light stabilizer, 0.1-0.5wt.% of metal passivator and 0-1wt.% of lubricant. The polypropylene material has certain aging-resistant and precipitation-resistant properties, but its aging-resistant and precipitation-resistant effects are not satisfactory enough for application in the field of actual automotive interiors. Chinese patent application CN109721839A discloses a high-gloss, low-linear expansion coefficient polypropylene composite material and its preparation method. The composite material is composed of the following raw materials by mass: 70-80 parts of polypropylene; 0-0.5 parts of nucleating agent; 1-1.5 parts of brightener; 15-20 parts of filler; 0.1-0.3 parts of antioxidant; 0.1-0.3 parts of lubricant; 0-1 parts of antibacterial agent; the mineral filler is composed of whiskers, mica, and nano-montmorillonite; wherein the whiskers are composed of calcium carbonate whiskers, magnesium sulfate whiskers, and basalt whiskers. The composite material of the invention has high gloss, can effectively reduce the linear expansion coefficient of polypropylene materials, and the material has antibacterial properties. At the same time, it can well solve the serious shrinkage phenomenon of polypropylene materials caused by post-crystallization in life, and has important practical benefits. However, if the amount of filler added is too large, it may cause a significant decrease in mechanical properties. At the same time, the antibacterial agent is added in a physical blending manner, and may precipitate after long-term use, resulting in a decrease in antibacterial properties. Summary of the invention

[0006] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a PP plastic for automobile interior and a preparation method thereof. The PP plastic has excellent resistance to ultraviolet aging, lasting antibacterial properties, good dimensional stability and excellent mechanical properties, can meet the comprehensive requirements of automobile interior materials for weather resistance, antibacterial properties, dimensional stability and toughness, and has broad application prospects.

[0007] To achieve the above object, the present invention provides the following technical solutions: A PP plastic for automobile interior decoration, comprising the following raw materials in parts by weight: 90-100 parts of polypropylene, 8-12 parts of POE, 20-25 parts of modified talc, 5-8 parts of compatibilizer, 0.7-1.1 parts of lubricant, and 0.4-0.7 parts of thermal stabilizer; the modified talc uses talc as a raw material, introduces ZnO / TiO2 into the talc by a hydrothermal method, and then introduces 5-amino-2-mercaptobenzimidazole and 1-(4,6-diamino-1,3,5-triazine-2-yl)guanidine in sequence in the form of chemical bonds.

[0008] In the present invention, polypropylene is used as the base material, POE is used as the toughening agent, modified talcum powder is used as the functional filler, maleic anhydride grafted polypropylene is used as the compatibilizer, magnesium stearate and / or silicone masterbatch are used as lubricants, and the compound of antioxidant 1010 and antioxidant 168 is used as the heat stabilizer, so that the prepared PP plastic has good comprehensive properties and is particularly suitable for automotive interior materials.

[0009] Preferably, a PP plastic for automotive interior, by weight, comprises the following raw materials: 95-100 parts of polypropylene, 10-12 parts of POE, 22-25 parts of modified talcum powder, 6-8 parts of compatibilizer, and 0.5-0.7 parts of heat stabilizer.

[0010] Preferably, the compatibilizer is maleic anhydride grafted polypropylene; the lubricant is one or two of magnesium stearate and silicone masterbatch; the heat stabilizer is composed of antioxidant 1010 and antioxidant 168 with a mass ratio of 2-3:1.

[0011] Preferably, the preparation method of the modified talcum powder comprises the following steps: S1. Pretreat the talcum powder: Add the talcum powder into deionized water, then add an aqueous zinc nitrate solution and a tetrabutyl titanate ethanol solution, perform ultrasonic dispersion, adjust the pH to 9-10, carry out a hydrothermal reaction, filter, wash and dry after the reaction is completed, add the solid product into an ethanol aqueous solution, then add vinyltriethoxysilane, and carry out a stirring reaction, filter, wash and dry after the reaction is completed to obtain pretreated talcum powder; S2. Organic talcum powder: Add the pretreated talcum powder in step S1 into toluene, then add 5-amino-2-mercaptobenzimidazole and benzophenone, carry out an ultraviolet light reaction under a nitrogen atmosphere, filter, wash and dry after the reaction is completed to obtain organic talcum powder; S3. Modified talcum powder: Add the organic talcum powder in step S2 into DMF, then add glutaraldehyde and 1-(4,6-diamino-1,3,5-triazin-2-yl)guanidine, adjust the pH to 4.5-5.5, carry out a constant temperature reaction under a nitrogen atmosphere, filter, wash and dry after the reaction is completed to obtain the modified talcum powder.

[0012] Preferably, in step S1, the mass fraction of zinc nitrate in the aqueous zinc nitrate solution is 30-35%, and the mass fraction of tetrabutyl titanate in the tetrabutyl titanate ethanol solution is 20-25%; the mass ratio of the talcum powder, deionized water, aqueous zinc nitrate solution, and tetrabutyl titanate ethanol solution is 50-60:800-1000:70-80:90-100, and the temperature of the hydrothermal reaction is 130-150°C and the time is 6-8 h.

[0013] In the present invention, ZnO / TiO2 nanoparticles are introduced onto the surface of talcum powder by a hydrothermal method. By utilizing the ultraviolet shielding effects of titanium dioxide and zinc oxide, the ultraviolet aging resistance of the material is preliminarily improved. The talcum powder itself has a lamellar structure, which can enhance the rigidity and dimensional stability of polypropylene.

[0014] Preferably, in step S1, the volume ratio of ethanol to water in the ethanol aqueous solution is 3 - 4:1, and the mass ratio of the solid product to vinyltriethoxysilane is 50 - 60:7 - 9; the temperature of the stirring reaction is 60 - 70 °C, and the time is 2 - 3 h.

[0015] In the present invention, vinyltriethoxysilane is introduced onto the talcum powder through a stirring reaction to improve the dispersibility of the talcum powder and the reactivity of subsequent reactions.

[0016] Preferably, in step S2, the mass ratio of the pretreated talcum powder, 5 - amino - 2 - mercaptobenzimidazole, and benzophenone is 60 - 70:3 - 4:0.2 - 0.3. The temperature of the ultraviolet light irradiation is 40 - 50 °C, the intensity of the ultraviolet light is 10 - 15 mW / cm 2 , the wavelength is 365 nm, and the time is 1 - 2 h.

[0017] In the present invention, through a thiol - ene reaction, 5 - amino - 2 - mercaptobenzimidazole is introduced into the talcum powder in the form of a covalent bond, further improving the aging resistance and antibacterial properties of the material.

[0018] Preferably, in step S3, the mass ratio of the organic talcum powder, glutaraldehyde, and 1 - (4,6 - diamino - 1,3,5 - triazin - 2 - yl)guanidine is 60 - 70:3.5 - 5:2.5 - 3.5. The temperature of the constant - temperature reaction is 50 - 60 °C, and the time is 3 - 4 h.

[0019] In the present invention, using glutaraldehyde as a cross - linker, 1 - (4,6 - diamino - 1,3,5 - triazin - 2 - yl)guanidine is introduced onto the talcum powder through a Schiff - base reaction. With the excellent ultraviolet absorption ability of the triazine ring structure and the antibacterial activity of the guanidine group, the ultraviolet aging resistance, long - lasting antibacterial property, and dimensional stability of the material are further improved.

[0020] The present invention also protects a preparation method of the above - mentioned PP plastic for automotive interiors, comprising the following steps: Weigh the raw materials according to the ratio. Mix polypropylene, POE, modified talcum powder, compatibilizer, lubricant, and heat stabilizer uniformly in a high - speed mixer to obtain a premix. Subsequently, add the premix into a twin - screw extruder and melt - extrude and pelletize to obtain the PP plastic for automotive interiors.

[0021] Preferably, the high-speed mixer rotates at 500-600 r / min for 10-15 min; the temperature of each section of the twin-screw extruder is 180-230 °C.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) The PP plastic for automotive interior provided by the present invention uses polypropylene as the base material, POE as the toughening agent, modified talcum powder as the functional filler, maleic anhydride grafted polypropylene as the compatibilizer, magnesium stearate and / or silicone masterbatch as the lubricant, and the compound of antioxidant 1010 and antioxidant 168 as the heat stabilizer, so that the prepared PP plastic has excellent ultraviolet aging resistance, persistent antibacterial property, good dimensional stability and excellent mechanical properties, can meet the comprehensive requirements of automotive interior materials for various properties such as weather resistance, antibacterial property, dimensional stability and toughness, and has broad application prospects.

[0023] (2) For the PP plastic for automotive interior provided by the present invention, the added modified talcum powder uses talcum powder as the raw material. Talcum powder itself has a lamellar structure, which can improve the rigidity and dimensional stability of polypropylene. ZnO / TiO2 nanoparticles are in-situ generated on the talcum powder by the hydrothermal method. By using the ultraviolet shielding effect of titanium dioxide and zinc oxide, the ultraviolet aging resistance of the material is initially improved, and at the same time, the heat resistance and rigidity are improved, and the dimensional stability of the PP plastic is improved. Compared with blending addition, there is a strong interaction between the in-situ generated nanoparticles and the talcum powder, effectively preventing the agglomeration between the nanoparticles and improving the mechanical properties of the PP plastic; subsequently, vinyltriethoxysilane is introduced onto the talcum powder to improve the dispersibility of the talcum powder and the activity of subsequent reactions; then, using the thiol-ene reaction, 5-amino-2-mercaptobenzimidazole is introduced onto the talcum powder, and then using the Schiff base reaction, with glutaraldehyde as the cross-linking agent, 1-(4,6-diamino-1,3,5-triazin-2-yl)guanidine is introduced onto the talcum powder. The 5-amino-2-mercaptobenzimidazole molecule contains a benzimidazole ring, which has a conjugated π-electron system structure and can absorb ultraviolet light. It synergistically acts with the triazine ring in 1-(4,6-diamino-1,3,5-triazin-2-yl)guanidine to improve the ultraviolet aging resistance of the PP plastic together; and the benzimidazole group and the guanidine group respectively destroy the microbial cell membrane through hydrophobic interaction and positive charge adsorption, realizing the long-term synergy of weather resistance and antibacterial property, and the functional groups are fixed by chemical bonds to avoid migration failure; at the same time, through a series of modifications on the surface of the talcum powder, the surface properties of the talcum powder are changed, and the compatibility with the polypropylene matrix is improved. The good interfacial bonding helps to transfer the stress from the polymer matrix to the talcum powder, thereby reducing the deformation of the polymer and improving the dimensional stability of the PP plastic.

[0024] (3)The PP plastic for automotive interior provided by the present invention efficiently combines multiple functions such as ultraviolet shielding of inorganic nanoparticles (ZnO / TiO2), ultraviolet absorption of organic small molecules (5-amino-2-mercaptobenzimidazole, benzophenone), and ultraviolet absorption and antibacterial properties of nitrogen-containing heterocycles (1-(4,6-diamino-1,3,5-triazin-2-yl)guanidine) on the surface of talcum powder, enabling the PP plastic to have multiple functions including ultraviolet shielding, ultraviolet absorption, antibacterial, and reinforcement, achieving a synergistic effect of multiple functions. At the same time, the precipitation of small molecules during the subsequent use of the PP plastic is prevented by means of chemical bonding, and the comprehensive performance is superior to that of the traditional talcum powder-filled PP system, endowing the material with good comprehensive performance. Detailed Embodiments

[0025] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0026] In the embodiments of the present invention, the polypropylene grade is Sinopec PPH-T03, the POE grade is Dow 8450 from the United States, and the particle size of the talcum powder is 2000 mesh. Example 1

[0027] A PP plastic for automotive interior, by weight, comprises the following raw materials: 95 parts of polypropylene, 10 parts of POE, 23 parts of modified talcum powder, 7 parts of maleic anhydride grafted polypropylene, 1 part of magnesium stearate, 0.6 part of heat stabilizer; Among them, the preparation method of the modified talcum powder comprises the following steps: S1. Pretreat the talcum powder: Add 55 g of talcum powder to 900 g of deionized water, then add 75 g of zinc nitrate aqueous solution (the mass fraction of zinc nitrate is 33%) and 95 g of tetrabutyl titanate ethanol solution (the mass fraction of tetrabutyl titanate is 23%), perform ultrasonic dispersion for 20 min, add ammonia water to adjust the pH to 9.5, carry out hydrothermal reaction at 140 °C for 7 h, filter, wash, and dry after the reaction to obtain a solid product; Add 55 g of the solid product to 800 mL of ethanol aqueous solution (the volume ratio of ethanol to water is 3.5:1), then add 8 g of vinyltriethoxysilane, stir and react at 65 °C for 2.5 h, filter, wash, and dry after the reaction to obtain the pretreated talcum powder; S2. Organic Talc: Add 65 g of pretreated talc in step S1 into 900 mL of toluene, then add 3.5 g of 5-amino-2-mercaptobenzimidazole and 0.25 g of benzophenone, and carry out an ultraviolet light irradiation reaction under a nitrogen atmosphere at a temperature of 45 °C, with the intensity of ultraviolet light being 13 mW / cm 2 , a wavelength of 365 nm, and a time of 1.5 h. After the reaction is completed, filter, wash, and dry to obtain organic talc; S3. Modified Talc: Add 65 g of organic talc in step S2 into 900 mL of DMF, then add 4.5 g of glutaraldehyde and 3 g of 1-(4,6-diamino-1,3,5-triazin-2-yl)guanidine, adjust the pH to 5, and carry out a constant temperature reaction under a nitrogen atmosphere at a reaction temperature of 55 °C for 3.5 h. After the reaction is completed, filter, wash, and dry to obtain the modified talc.

[0028] The heat stabilizer is composed of antioxidant 1010 and antioxidant 168 with a mass ratio of 2.5:1.

[0029] A preparation method of PP plastic for automobile interior trim includes the following steps: Weigh the raw materials according to the ratio, mix polypropylene, POE, modified talc, maleic anhydride grafted polypropylene, magnesium stearate, and heat stabilizer evenly in a high-speed mixer at a rotation speed of 550 r / min for 13 min to obtain a premix. Subsequently, add the premix into a twin-screw extruder for melt extrusion granulation. The temperature settings of each section of the twin-screw extruder are 150 °C for the first section, 170 °C for the second section, 185 °C for the third section, 195 °C for the fourth section, 215 °C for the fifth section, 225 °C for the sixth section, and 205 °C for the die head, thus obtaining the PP plastic for automobile interior trim. Example 2

[0030] A PP plastic for automobile interior trim, by weight, includes the following raw materials: 95 parts of polypropylene, 10 parts of POE, 22 parts of modified talc, 6 parts of maleic anhydride grafted polypropylene, 0.9 part of silicone masterbatch, and 0.5 part of heat stabilizer; Among them, the preparation method of the modified talc includes the following steps: S1. Pretreatment of Talc Powder: Add 55 g of talc powder into 900 g of deionized water, then add 75 g of zinc nitrate aqueous solution (mass fraction of zinc nitrate is 32%) and 95 g of tetrabutyl titanate ethanol solution (mass fraction of tetrabutyl titanate is 22%), carry out ultrasonic dispersion for 20 min, add ammonia water to adjust the pH to 9.5, carry out hydrothermal reaction at 140 °C for 7 h, after the reaction is completed, filter, wash and dry to obtain a solid product; Add 55 g of the solid product into 800 mL of ethanol aqueous solution (volume ratio of ethanol to water is 3.5:1), then add 8 g of vinyltriethoxysilane, stir and react at 65 °C for 2.5 h, after the reaction is completed, filter, wash and dry to obtain the pretreated talc powder; S2. Organic Talc Powder: Add 65 g of the pretreated talc powder in step S1 into 900 mL of toluene, then add 3.5 g of 5-amino-2-mercaptobenzimidazole and 0.25 g of benzophenone, carry out ultraviolet light irradiation reaction under a nitrogen atmosphere, the temperature is 45 °C, the intensity of ultraviolet light is 12 mW / cm 2 , the wavelength is 365 nm, and the time is 1.5 h, after the reaction is completed, filter, wash and dry to obtain the organic talc powder; S3. Modified Talc Powder: Add 65 g of the organic talc powder in step S2 into 900 mL of DMF, then add 4 g of glutaraldehyde and 3 g of 1-(4,6-diamino-1,3,5-triazin-2-yl)guanidine, adjust the pH to 5, carry out a constant temperature reaction under a nitrogen atmosphere, the reaction temperature is 55 °C, and the time is 3.5 h, after the reaction is completed, filter, wash and dry to obtain the modified talc powder.

[0031] The heat stabilizer is composed of antioxidant 1010 and antioxidant 168 with a mass ratio of 2.5:1.

[0032] A preparation method of the PP plastic for automobile interior decoration as described above, comprising the following steps: Weigh the raw materials according to the ratio, mix polypropylene, POE, modified talc powder, maleic anhydride grafted polypropylene, silicone masterbatch and heat stabilizer evenly in a high-speed mixer at a rotation speed of 550 r / min for 12 min to obtain a premix, and then add the premix into a twin-screw extruder for melt extrusion and pelletization. The temperature of each section of the twin-screw extruder is set as follows: the first section is 150 °C, the second section is 170 °C, the third section is 185 °C, the fourth section is 195 °C, the fifth section is 215 °C, the sixth section is 225 °C, and the head is 205 °C, thus obtaining the PP plastic for automobile interior decoration. Example 3

[0033] A PP plastic for automobile interior decoration, by weight, comprises the following raw materials: 90 parts of polypropylene, 8 parts of POE, 20 parts of modified talc powder, 5 parts of maleic anhydride grafted polypropylene, 0.7 part of magnesium stearate, 0.4 part of heat stabilizer; Among them, the preparation method of the modified talcum powder includes the following steps: S1. Pretreat the talcum powder: Add 50 g of talcum powder to 800 g of deionized water, then add 70 g of zinc nitrate aqueous solution (the mass fraction of zinc nitrate is 30%) and 90 g of tetrabutyl titanate ethanol solution (the mass fraction of tetrabutyl titanate is 20%), perform ultrasonic dispersion for 20 min, add ammonia water to adjust the pH to 9, carry out hydrothermal reaction at 130 °C for 8 h, after the reaction is completed, filter, wash, and dry to obtain a solid product; Add 50 g of the solid product to 800 mL of ethanol aqueous solution (the volume ratio of ethanol to water is 3:1), then add 7 g of vinyltriethoxysilane, stir and react at 60 °C for 3 h, after the reaction is completed, filter, wash, and dry to obtain the pretreated talcum powder; S2. Organic talcum powder: Add 60 g of the pretreated talcum powder in step S1 to 900 mL of toluene, then add 3 g of 5-amino-2-mercaptobenzimidazole and 0.2 g of benzophenone, carry out ultraviolet light irradiation reaction under a nitrogen atmosphere, the temperature is 40 °C, the intensity of ultraviolet light is 10 mW / cm 2 , the wavelength is 365 nm, and the time is 2 h. After the reaction is completed, filter, wash, and dry to obtain the organic talcum powder; S3. Modified talcum powder: Add 60 g of the organic talcum powder in step S2 to 900 mL of DMF, then add 3.5 g of glutaraldehyde and 2.5 g of 1-(4,6-diamino-1,3,5-triazin-2-yl)guanidine, adjust the pH to 4.5, carry out a constant temperature reaction under a nitrogen atmosphere, the reaction temperature is 50 °C, and the time is 4 h. After the reaction is completed, filter, wash, and dry to obtain the modified talcum powder.

[0034] The heat stabilizer is composed of antioxidant 1010 and antioxidant 168 with a mass ratio of 2:1.

[0035] A preparation method of the PP plastic for automobile interior decoration as described above includes the following steps: Weigh the raw materials according to the ratio, mix polypropylene, POE, modified talcum powder, maleic anhydride grafted polypropylene, magnesium stearate, and heat stabilizer evenly in a high-speed mixer at a rotation speed of 500 r / min for 15 min to obtain a premix. Subsequently, add the premix to a twin-screw extruder for melt extrusion and granulation. The temperature of each section of the twin-screw extruder is set as follows: the first section is 150 °C, the second section is 170 °C, the third section is 180 °C, the fourth section is 190 °C, the fifth section is 210 °C, the sixth section is 220 °C, and the head is 200 °C, thus obtaining the PP plastic for automobile interior decoration. Example 4

[0036] A PP plastic for automobile interior decoration, by weight, includes the following raw materials: 100 parts of polypropylene, 12 parts of POE, 25 parts of modified talcum powder, 8 parts of maleic anhydride grafted polypropylene, 1.1 parts of silicone masterbatch, 0.7 parts of heat stabilizer; Among them, the preparation method of the modified talcum powder includes the following steps: S1. Pretreat the talcum powder: Add 60 g of talcum powder to 1000 g of deionized water, then add 80 g of zinc nitrate aqueous solution (the mass fraction of zinc nitrate is 35%) and 100 g of tetrabutyl titanate ethanol solution (the mass fraction of tetrabutyl titanate is 25%), perform ultrasonic dispersion for 20 min, add ammonia water to adjust the pH to 10, carry out hydrothermal reaction at 150 °C for 6 h, after the reaction is completed, filter, wash, and dry to obtain a solid product; Add 60 g of the solid product to 800 mL of ethanol aqueous solution (the volume ratio of ethanol to water is 4:1), then add 9 g of vinyltriethoxysilane, stir and react at 70 °C for 2 h, after the reaction is completed, filter, wash, and dry to obtain the pretreated talcum powder; S2. Organic talcum powder: Add 70 g of the pretreated talcum powder in step S1 to 900 mL of toluene, then add 4 g of 5-amino-2-mercaptobenzimidazole and 0.3 g of benzophenone, carry out ultraviolet light irradiation reaction under a nitrogen atmosphere, the temperature is 50 °C, the intensity of ultraviolet light is 15 mW / cm 2 , the wavelength is 365 nm, and the time is 1 h. After the reaction is completed, filter, wash, and dry to obtain the organic talcum powder; S3. Modified talcum powder: Add 70 g of the organic talcum powder in step S2 to 900 mL of DMF, then add 5 g of glutaraldehyde and 3.5 g of 1-(4,6-diamino-1,3,5-triazin-2-yl)guanidine, adjust the pH to 5.5, carry out a constant temperature reaction under a nitrogen atmosphere, the reaction temperature is 60 °C, and the time is 3 h. After the reaction is completed, filter, wash, and dry to obtain the modified talcum powder.

[0037] The heat stabilizer is composed of antioxidant 1010 and antioxidant 168 with a mass ratio of 3:1.

[0038] A preparation method of the PP plastic for automobile interior trim as described above includes the following steps: Weigh the raw materials according to the ratio, mix polypropylene, POE, modified talcum powder, maleic anhydride grafted polypropylene, silicone masterbatch, and heat stabilizer evenly in a high-speed mixer at a rotation speed of 600 r / min for 10 min to obtain a premix. Subsequently, add the premix to a twin-screw extruder, melt and extrude into pellets. The temperature settings of each section of the twin-screw extruder are 150 °C for the first section, 170 °C for the second section, 190 °C for the third section, 200 °C for the fourth section, 220 °C for the fifth section, 230 °C for the sixth section, and 210 °C for the die head, thus obtaining the PP plastic for automobile interior trim. Comparative Example 1

[0039] A PP plastic for automotive interior, by weight, includes the following raw materials: 95 parts of polypropylene, 10 parts of POE, 23 parts of modified talc powder, 7 parts of maleic anhydride grafted polypropylene, 1 part of magnesium stearate, 0.6 part of heat stabilizer; Among them, the preparation method of the modified talc powder includes the following steps: S1. Pretreat the talc powder: Add 55 g to 800 mL of ethanol aqueous solution (volume ratio of ethanol to water is 3.5:1), then add 8 g of vinyltriethoxysilane, stir and react at 65 °C for 2.5 h. After the reaction is completed, filter, wash, and dry to obtain pretreated talc powder; S2. Organic talc powder: Add 65 g of the pretreated talc powder in step S1 to 900 mL of toluene, then add 3.5 g of 5-amino-2-mercaptobenzimidazole and 0.25 g of benzophenone, and carry out ultraviolet light irradiation reaction under a nitrogen atmosphere. The temperature is 45 °C, the intensity of ultraviolet light is 13 mW / cm 2 , the wavelength is 365 nm, and the time is 1.5 h. After the reaction is completed, filter, wash, and dry to obtain organic talc powder; S3. Modified talc powder: Add 65 g of the organic talc powder in step S2 to 900 mL of DMF, then add 4.5 g of glutaraldehyde and 3 g of 1-(4,6-diamino-1,3,5-triazin-2-yl)guanidine, adjust the pH to 5, and carry out a constant temperature reaction under a nitrogen atmosphere. The reaction temperature is 55 °C and the time is 3.5 h. After the reaction is completed, filter, wash, and dry to obtain the modified talc powder.

[0040] The heat stabilizer is composed of antioxidant 1010 and antioxidant 168 with a mass ratio of 2.5:1.

[0041] A preparation method of a PP plastic for automotive interior includes the following steps: Weigh the raw materials according to the ratio, mix polypropylene, POE, modified talc powder, maleic anhydride grafted polypropylene, magnesium stearate, and heat stabilizer evenly in a high-speed mixer at a rotation speed of 550 r / min for 13 min to obtain a premix. Subsequently, add the premix into a twin-screw extruder, melt and extrude into pellets. The temperature settings of each section of the twin-screw extruder are 150 °C for the first section, 170 °C for the second section, 185 °C for the third section, 195 °C for the fourth section, 215 °C for the fifth section, 225 °C for the sixth section, and 205 °C for the die head, thus obtaining the PP plastic for automotive interior.

[0042] Compared with Example 1, ZnO / TiO2 nanoparticles were not introduced onto the talc powder in this comparative example. Comparative Example 2

[0043] A PP plastic for automotive interior, by weight, includes the following raw materials: 95 parts of polypropylene, 10 parts of POE, 23 parts of modified talc powder, 7 parts of maleic anhydride grafted polypropylene, 1 part of magnesium stearate, 0.6 part of heat stabilizer; Among them, the preparation method of the modified talc powder includes the following steps: S1. Pretreat the talc powder: Add 55 g of talc powder to 900 g of deionized water, then add 75 g of zinc nitrate aqueous solution (the mass fraction of zinc nitrate is 33%) and 95 g of tetrabutyl titanate ethanol solution (the mass fraction of tetrabutyl titanate is 23%), carry out ultrasonic dispersion for 20 min, add ammonia water to adjust the pH to 9.5, carry out hydrothermal reaction at 140 °C for 7 h, after the reaction is completed, filter, wash, and dry to obtain a solid product; Add 55 g of the solid product to 800 mL of ethanol aqueous solution (the volume ratio of ethanol to water is 3.5:1), then add 8 g of vinyltriethoxysilane, stir and react at 65 °C for 2.5 h, after the reaction is completed, filter, wash, and dry to obtain the pretreated talc powder; S2. Modify the talc powder: Add 65 g of the pretreated talc powder in step S1 to 900 mL of toluene, then add 3.5 g of 5-amino-2-mercaptobenzimidazole and 0.25 g of benzophenone, carry out ultraviolet light irradiation reaction under a nitrogen atmosphere, the temperature is 45 °C, the intensity of ultraviolet light is 13 mW / cm 2 , the wavelength is 365 nm, the time is 1.5 h, after the reaction is completed, filter, wash, and dry to obtain the modified talc powder.

[0044] The heat stabilizer is composed of antioxidant 1010 and antioxidant 168 with a mass ratio of 2.5:1.

[0045] A preparation method of an automotive interior PP plastic includes the following steps: Weigh the raw materials according to the ratio, mix polypropylene, POE, modified talc powder, maleic anhydride grafted polypropylene, magnesium stearate, and heat stabilizer evenly in a high-speed mixer at a rotation speed of 550 r / min for 13 min to obtain a premix, and then add the premix to a twin-screw extruder for melt extrusion and pelletization. The temperature of each section of the twin-screw extruder is set as follows: the first section is 150 °C, the second section is 170 °C, the third section is 185 °C, the fourth section is 195 °C, the fifth section is 215 °C, the sixth section is 225 °C, and the head is 205 °C, thus obtaining the automotive interior PP plastic.

[0046] Compared with Example 1, 1-(4,6-diamino-1,3,5-triazin-2-yl)guanidine was not introduced onto the talc powder in this comparative example. Comparative Example 3

[0047] An automotive interior PP plastic, by weight, includes the following raw materials: 95 parts of polypropylene, 10 parts of POE, 23 parts of modified talc powder, 7 parts of maleic anhydride grafted polypropylene, 1 part of magnesium stearate, 0.6 part of heat stabilizer; Among them, the preparation method of the modified talc powder includes the following steps: S1. Pretreat the talc powder: Add 55 g of talc powder to 900 g of deionized water, then add 75 g of zinc nitrate aqueous solution (the mass fraction of zinc nitrate is 33%) and 95 g of tetrabutyl titanate ethanol solution (the mass fraction of tetrabutyl titanate is 23%), perform ultrasonic dispersion for 20 min, add ammonia water to adjust the pH to 9.5, carry out hydrothermal reaction at 140 °C for 7 h, after the reaction is completed, filter, wash, and dry to obtain a solid product; Add 55 g of the solid product to 800 mL of ethanol aqueous solution (the volume ratio of ethanol to water is 3.5:1), then add 8 g of vinyltriethoxysilane, stir and react at 65 °C for 2.5 h, after the reaction is completed, filter, wash, and dry to obtain the pretreated talc powder; S2. Modify the talc powder: Add 65 g of the pretreated talc powder in step S1 to 900 mL of DMF, then add 0.5 g of azobisisobutyronitrile and 3 g of 1-(4,6-diamino-1,3,5-triazin-2-yl)guanidine, adjust the pH to 5, carry out a constant temperature reaction under a nitrogen atmosphere, the reaction temperature is 75 °C, and the time is 3.5 h, after the reaction is completed, filter, wash, and dry to obtain the modified talc powder.

[0048] The heat stabilizer is composed of antioxidant 1010 and antioxidant 168 with a mass ratio of 2.5:1.

[0049] A preparation method of an automotive interior PP plastic includes the following steps: Weigh the raw materials according to the ratio, mix polypropylene, POE, modified talc powder, maleic anhydride grafted polypropylene, magnesium stearate, and heat stabilizer evenly in a high-speed mixer at a rotation speed of 550 r / min for 13 min to obtain a premix. Subsequently, add the premix to a twin-screw extruder, melt and extrude into pellets, and the temperature settings of each section of the twin-screw extruder are 150 °C for the first section, 170 °C for the second section, 185 °C for the third section, 195 °C for the fourth section, 215 °C for the fifth section, 225 °C for the sixth section, and 205 °C for the die head, thus obtaining the automotive interior PP plastic.

[0050] Compared with Example 1, 5-amino-2-mercaptobenzimidazole was not introduced onto the talc powder in this comparative example. Comparative Example 4

[0051] An automotive interior PP plastic, by weight, includes the following raw materials: 95 parts of polypropylene, 10 parts of POE, 23 parts of modified talc powder, 7 parts of maleic anhydride grafted polypropylene, 1 part of magnesium stearate, 0.6 part of heat stabilizer; Among them, the preparation method of the modified talcum powder includes the following steps: Add 55 g of talcum powder into 900 g of deionized water, then add 75 g of zinc nitrate aqueous solution (the mass fraction of zinc nitrate is 33%) and 95 g of tetrabutyl titanate ethanol solution (the mass fraction of tetrabutyl titanate is 23%), carry out ultrasonic dispersion for 20 min, add ammonia water to adjust the pH to 9.5, carry out hydrothermal reaction at 140 °C for 7 h, after the reaction is completed, filter, wash, and dry to obtain a solid product; add 55 g of the solid product into 800 mL of ethanol aqueous solution (the volume ratio of ethanol to water is 3.5:1), then add 8 g of vinyltriethoxysilane, stir and react at 65 °C for 2.5 h, after the reaction is completed, filter, wash, and dry to obtain the modified talcum powder.

[0052] The heat stabilizer is composed of antioxidant 1010 and antioxidant 168 with a mass ratio of 2.5:1.

[0053] A preparation method of PP plastic for automobile interior decoration includes the following steps: Weigh the raw materials according to the ratio, mix polypropylene, POE, modified talcum powder, maleic anhydride grafted polypropylene, magnesium stearate, and heat stabilizer evenly in a high-speed mixer at a rotation speed of 550 r / min for 13 min to obtain a premix. Subsequently, add the premix into a twin-screw extruder, melt and extrude into pellets. The temperature settings of each section of the twin-screw extruder are 150 °C for the first section, 170 °C for the second section, 185 °C for the third section, 195 °C for the fourth section, 215 °C for the fifth section, 225 °C for the sixth section, and 205 °C for the head, thus obtaining the PP plastic for automobile interior decoration.

[0054] Compared with Example 1, 5-amino-2-mercaptobenzimidazole and 1-(4,6-diamino-1,3,5-triazin-2-yl)guanidine were not introduced onto the talcum powder in this comparative example.

[0055] The PP plastics for automotive interiors prepared in Examples 1-4 and Comparative Examples 1-3 were made into test specimens to test their properties. Among them, the tensile strength was tested according to the standard of GB / T 1040.2-2022 Plastics - Determination of tensile properties - Part 2: Test conditions for moulding and extrusion plastics. The specimen had a size of 180 mm × 10 mm × 4 mm, and the tensile speed was 10 mm / min. The flexural strength was tested according to the standard of GB / T 9341-2008 Plastics - Determination of flexural properties. The specimen size was 80 mm × 10 mm × 4 mm. The notched impact strength was tested according to the standard of GB / T 1843-2008 Plastics - Determination of Izod impact strength. The specimen had a size of 80 mm × 10 mm × 4 mm, and the remaining notch thickness was 2 mm. The linear expansion coefficient was tested according to the standard of GB / T 1036-2008 Plastics - Determination of linear thermal expansion coefficient from -30 °C to 30 °C - Quartz dilatometer method. The UV resistance aging performance was tested according to the standard of GB / T 16422.3-2022 Plastics - Methods of exposure to laboratory light sources - Part 3: Fluorescent UV lamps. The aging conditions were: UV intensity 210 W / m 2 , aging temperature 60 °C, aging time 168 h. After aging, the tensile properties and antibacterial properties of the test samples were tested. The antibacterial test was carried out according to the standard of GB / T 31402-2023 Determination of antibacterial activity on the surface of plastics and other non-porous materials. Short-term antibacterial property means that the antibacterial test starts 24 hours after the antibacterial test sample is molded. Long-term antibacterial property means that the antibacterial test is carried out after the antibacterial test sample is aged. The test results are shown in Table 1 and Table 2 below: Table 1 Tensile strength (MPa) Flexural strength (MPa) <![CDATA[Notched impact strength (kJ / m 2 )]]> <![CDATA[Coefficient of linear expansion (×10 -6 )]]> Example 1 22.6 28.3 25.2 39 Example 2 22.1 27.9 24.7 41 Example 3 22.8 28.7 25.9 47 Example 4 21.5 27.2 24.6 45 Comparative Example 1 18.3 23.1 21.8 71 Comparative Example 2 20.4 25.7 23.6 56 Comparative Example 3 20.9 25.2 23.3 52 Comparative Example 4 20.2 24.6 22.7 61 Table 2

[0056] As can be seen from Table 1 and Table 2 above, the PP plastics for automotive interiors prepared by the present invention have good weather resistance, long-lasting antibacterial property, dimensional stability and other properties, and also have good mechanical properties, showing good application prospects. In Comparative Example 1, due to the absence of ZnO / TiO2 nanoparticles, the mechanical properties and dimensional stability of polypropylene decreased significantly. In Comparative Example 2, due to the absence of 1-(4,6-diamino-1,3,5-triazin-2-yl)guanidine, and in Comparative Example 3, due to the absence of 5-amino-2-mercaptobenzimidazole, the UV resistance aging performance and long-lasting antibacterial property of the PP plastics decreased to some extent. In Comparative Example 4, due to the absence of 1-(4,6-diamino-1,3,5-triazin-2-yl)guanidine and 5-amino-2-mercaptobenzimidazole, its properties decreased significantly.

[0057] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A PP plastic for automobile interior, characterized in that: By weight, it includes the following raw materials: 90-100 parts of polypropylene, 8-12 parts of POE, 20-25 parts of modified talc, 5-8 parts of compatibilizer, 0.7-1.1 parts of lubricant, and 0.4-0.7 parts of thermal stabilizer; the modified talc uses talc as a raw material, introduces ZnO / TiO2 into the talc by a hydrothermal method, and then introduces 5-amino-2-mercaptobenzimidazole and 1-(4,6-diamino-1,3,5-triazine-2-yl)guanidine in sequence in the form of chemical bonds.

2. The PP plastic for automobile interior decoration according to claim 1, characterized in that: The composition comprises the following raw materials in parts by weight: 95-100 parts of polypropylene, 10-12 parts of POE, 22-25 parts of modified talc, 6-8 parts of compatibilizer and 0.5-0.7 parts of heat stabilizer.

3. The PP plastic for automobile interior decoration according to claim 1, characterized in that: The compatibilizer is maleic anhydride grafted polypropylene; the lubricant is one or two of magnesium stearate and silicone masterbatch; the heat stabilizer is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 2-3:

1.

4. The PP plastic for automobile interior decoration according to claim 1, characterized in that: The preparation method of the modified talcum powder comprises the following steps: S1, adding talcum powder to deionized water, adding zinc nitrate aqueous solution and tetrabutyl titanate ethanol solution, adjusting the pH, carrying out hydrothermal reaction to obtain a solid product, adding the solid product to ethanol aqueous solution, adding vinyl triethoxysilane, stirring for reaction, and obtaining pretreated talcum powder; S2, adding the pretreated talc powder to toluene, and then adding 5-amino-2-mercaptobenzimidazole and benzophenone, and performing ultraviolet light reaction. After the reaction is completed, organic talc powder is obtained; S3, adding organic talc powder into DMF, and then adding glutaraldehyde and 1-(4,6-diamino-1,3,5-triazine-2-yl)guanidine, adjusting the pH, and reacting at a constant temperature. After the reaction is completed, the modified talc powder is obtained.

5. The PP plastic for automobile interior decoration according to claim 1, characterized in that: In step S1, the mass fraction of zinc nitrate in the zinc nitrate aqueous solution is 30-35%, and the mass fraction of tetrabutyl titanate in the tetrabutyl titanate ethanol solution is 20-25%; the mass ratio of talcum powder, deionized water, zinc nitrate aqueous solution, and tetrabutyl titanate ethanol solution is 50-60:800-1000:70-80:90-100, and the temperature of the hydrothermal reaction is 130-150°C, and the time is 6-8h.

6. The PP plastic for automobile interior decoration according to claim 1, characterized in that: In step S1, the mass ratio of the solid product to vinyltriethoxysilane is 50-60:7-9; the stirring reaction temperature is 60-70° C. and the reaction time is 2-3 h.

7. The PP plastic for automobile interior decoration according to claim 1, characterized in that: The mass ratio of the pretreated talc, 5-amino-2-mercaptobenzimidazole and benzophenone in step S2 is 60-70:3-4:0.2-0.3, the temperature of the ultraviolet light reaction is 40-50°C, and the intensity of the ultraviolet light is 10-15mW / cm 2 , wavelength is 365nm, time is 1-2h.

8. The PP plastic for automobile interior decoration according to claim 1, characterized in that: In step S3, the mass ratio of the organic talc, glutaraldehyde and 1-(4,6-diamino-1,3,5-triazine-2-yl)guanidine is 60-70:3.5-5:2.5-3.5, and the isothermal reaction temperature is 50-60° C. and the reaction time is 3-4 h.

9. A method for preparing PP plastic for automobile interior decoration according to any one of claims 1 to 8, characterized in that: The following steps are involved: The raw materials are weighed according to the ratio, and polypropylene, POE, modified talcum powder, compatibilizer, lubricant and heat stabilizer are uniformly mixed in a high-speed mixer to obtain a premix, and then the premix is ​​added to a twin-screw extruder, melt-extruded and granulated to obtain the PP plastic for automotive interior.

10. The preparation method according to claim 9, characterized in that: The rotation speed of the high-speed mixer is 500-600 r / min, and the time is 10-15 min; the temperature of each section of the twin-screw extruder is 130-230° C.

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