High-performance low-cost polypropylene composite material for toilet lid and preparation method thereof

Abstract

The invention relates to the field of high polymer materials, and particularly discloses a high-performance low-cost polypropylene composite material for a toilet lid and a preparation method of the high-performance low-cost polypropylene composite material. The polypropylene composite material is prepared from the following raw materials in parts by weight: 70 to 80 parts of polypropylene, 15 to 25 parts of composite filler, 5 to 8 parts of SEBS (Styrene-Ethylene-Butylene-Styrene) flexibilizer, 0.1 to 0.3 part of beta crystal form nucleating agent, 1 to 2 parts of silver-loaded zinc zeolite antibacterial agent, 0.5 to 1.0 part of organosilicon quaternary ammonium salt and 0.5 to 1.0 part of other auxiliaries. The polypropylene composite material provided by the invention has relatively high rigidity and relatively strong toughness, breaks through the bottleneck of'mutual loss of toughness and rigidity 'of a traditional stiffening material, realizes a contact-type and non-contact-type dual antibacterial mode, achieves a long-acting antibacterial effect, and has extremely high antibacterial performance.

Description

Technical Field

[0001] This application relates to the field of polymer materials. Specifically, it relates to a polypropylene composite material for manufacturing toilet lids. More specifically, it relates to a modified polypropylene composite material with high rigidity, impact resistance, antibacterial properties and low cost, and a preparation method thereof. Background Art

[0002] Polypropylene (PP) composite materials are widely used in many fields such as packaging, automotive, construction, and electronics due to their good chemical stability, mechanical properties, heat resistance, easy processing, and low cost. Among them, toilet lids made of polypropylene composite materials have many significant advantages compared to toilet lids made of other materials. Specifically, firstly, polypropylene composite materials are famous for their excellent durability, with strong impact resistance and wear resistance, and can withstand the pressure and collision in daily use, ensuring that they are not easily damaged during long-term use. Secondly, polypropylene composite materials have excellent waterproof performance and are not easy to absorb water, making them suitable for the humid bathroom environment and avoiding the disadvantages of wood being prone to deformation and ceramics being fragile. In addition, the surface of the polypropylene toilet lid is smooth, very convenient for cleaning and maintenance, can effectively prevent dirt accumulation, and maintain hygiene. At the same time, polypropylene composite materials are also non-toxic and harmless environmental protection materials, meeting the health needs of modern families. Finally, polypropylene materials are light, easy to install and disassemble, and relatively affordable in price, with extremely high cost performance. Therefore, polypropylene toilet lids are undoubtedly an ideal choice in terms of durability, hygiene and economy.

[0003] However, existing polypropylene composite materials still have problems such as being prone to brittle fracture at low temperatures, being prone to deformation under long-term load, and having poor antibacterial properties in the application of toilet lids. Although some modified polypropylene composite materials have improved their performance by adding expensive toughening agents (such as POE), antibacterial masterbatches or mixing with ABS, there is still a phenomenon of mutual damage between toughness and rigidity, and there is still a large room for improvement in antibacterial ability. Summary of the Invention

[0004] In order to solve the above technical problems, this application provides a high-performance and low-cost polypropylene composite material for toilet lids and a preparation method thereof.

[0005] In the first aspect, a high-performance and low-cost polypropylene composite material for toilet lids provided by this application adopts the following technical scheme: A high-performance and low-cost polypropylene composite material for toilet lids, the raw materials used include the following components in parts by weight: 70 - 80 parts of polypropylene; 15 - 25 parts of composite filler; 5 - 8 parts of SEBS toughening agent; 0.1 - 0.3 parts of β-crystal nucleating agent; 1-2 parts of silver-loaded zinc zeolite antibacterial agent; 0.5-1.0 part of organosilicon quaternary ammonium salt; 0.5-1.0 part of other additives.

[0006] Preferably, the composite filler comprises talcum powder and calcium carbonate in a weight ratio of 1:(0.5-2.0).

[0007] By adopting the above technical solution, the present application uses talcum powder and calcium carbonate in a certain ratio in combination, which can not only give full play to the synergistic effect between them, greatly improve the rigidity of the polypropylene composite material, but also reduce the raw material cost. At the same time, the addition of the β-crystal nucleating agent can induce most of the α-crystals in the polypropylene to transform into β-crystals. The β-crystals are like snowflakes, with interfaces crossing each other, and cracks are not easy to transmit when fractured, which can greatly improve the toughness of the polypropylene composite material. And the superposition of the SEBS toughening agent can carry out synergistic toughening. While the polypropylene crystal form is transformed, the size of the SEBS phase becomes smaller and the dispersion becomes more uniform. Under the action of external force, the SEBS phase in the polypropylene composite material acts as a stress concentration point. Not only cavitation will occur inside the SEBS phase and at the interface layer between the SEBS phase and the PP, but also a large amount of shear yield deformation will be induced in the polypropylene matrix in the polypropylene composite material, endowing the polypropylene composite material with better toughness, breaking through the limitation of the large amount of traditional toughening agent added, and under the action of the composite filler, enabling the polypropylene composite material of the present application to have both high flexural modulus and high impact strength, breaking through the bottleneck of "toughness-rigidity mutual damage" of traditional rigidifying materials.

[0008] In addition, the present application also uses the silver-loaded zinc zeolite antibacterial agent and the organosilicon quaternary ammonium salt in combination, giving full play to the synergistic effect between them, realizing double antibacterial of contact type and non-contact type, achieving the purpose of long-term antibacterial, and greatly improving the antibacterial performance of the polypropylene composite material.

[0009] In a specific embodiment of the present application, the other additives include antioxidant 1010 and lubricant calcium stearate in a weight ratio of (0.1-0.3):(0.4-0.7).

[0010] Preferably, the SEBS toughening agent is prepared by the following method: Mix SEBS, glycidyl methacrylate, diisopropylbenzene peroxide and styrene in a weight ratio of 100:(2.5-3.5):(0.25-0.35):(5-7), then react at a temperature of 180-200 °C and a rotation speed of 65-75 r / min for 3-7 min, then cool and pelletize, and then obtain the SEBS toughening agent after post-treatment and purification.

[0011] By adopting the above technical solution, in this application, dicumyl peroxide (DCP) is used as an initiator, glycidyl methacrylate (GMA) is used as a graft monomer, and styrene is used as a co-graft monomer. A functionalized SEBS toughening agent is prepared through a free radical melt grafting technique. When this SEBS toughening agent is melt blended with polypropylene, the interfacial bonding force can be enhanced through an in-situ compatibilization reaction, improving the problem of poor compatibility between polypropylene and the SEBS toughening agent, thereby enhancing the toughening effect of the SEBS toughening agent on the polypropylene composite material. Moreover, experimental data prove that compared with using maleic anhydride as a graft monomer or using a mixture of maleic anhydride and glycidyl methacrylate as a graft monomer, using glycidyl methacrylate as a graft monomer in this application enables the finally prepared polypropylene composite material to have better toughness.

[0012] Preferably, the β-crystal nucleating agent comprises pimelic acid and calcium stearate in a weight ratio of 3:(7 - 10).

[0013] By adopting the above technical solution, this application optimizes the ratio between pimelic acid and calcium stearate in the β-crystal nucleating agent, ensuring that the addition amount of calcium stearate is within the optimal ratio range, enabling pimelic acid and calcium stearate to immediately undergo a chemical reaction when mixed and melted with polypropylene to generate the highly efficient β-crystal nucleating agent calcium pimelate, thereby promoting the formation of a higher purity β-crystal in polypropylene.

[0014] Preferably, the raw materials further include 1.4 - 1.6 parts by weight of a dispersant.

[0015] Preferably, the dispersant is prepared by the following method: a. Dissolve 28 - 32 parts by weight of 12 - hydroxystearic acid in acetone, then add 0.005 - 0.015 parts by weight of dibutyltin dilaurate and heat to 50 - 60 °C, and then add 17 - 18 parts by weight of tolylene diisocyanate for a constant temperature reaction for 1.5 - 2.5 h; b. Dissolve 100 - 110 parts by weight of hyperbranched polyester in N,N - dimethylformamide, then mix it with the product obtained in step a, and heat to 85 - 95 °C for a condensation reflux reaction for 5 - 7 h, then stop the reaction and perform vacuum distillation to obtain the dispersant.

[0016] By adopting the above technical solution, the present application synthesizes a dispersant using hyperbranched polyester, 12-hydroxy stearic acid, and toluene diisocyanate as the main raw materials, and mixes it with components such as a composite filler. The anchoring groups of the dispersant can adsorb on the surface of the inorganic powder particles of the composite filler, and through the stretching of the solvation chains in the polymer groups of polypropylene, a three-dimensional steric hindrance barrier effect is formed when the inorganic powder particles of the composite filler approach each other, thereby playing a role in uniformly dispersing the composite filler, greatly improving the dispersibility of the composite filler in the polypropylene matrix, and enhancing the interfacial compatibility between the composite filler and the polypropylene matrix, so that the composite filler can fully exert its reinforcing effect on the polypropylene composite material, and further improving the rigidity of the polypropylene composite material.

[0017] Preferably, the organosilicon quaternary ammonium salt is prepared by the following method: I. Heat didodecylamine and anhydrous acetonitrile to reflux, then add benzyl chloride and continue reflux reaction for 18 - 22 h, then cool to room temperature, filter by suction, and wash to obtain benzyl didodecylamine; wherein, the molar ratio of didodecylamine to benzyl chloride is 1:(1.0 - 1.4); II. Dissolve benzyl didodecylamine in ethylene glycol, then add γ-chloropropyltrimethoxysilane at a temperature of 105 - 115 °C and carry out a constant-temperature closed reaction for 44 - 46 h, then after evaporation, cooling, filtration, washing, and drying, obtain the organosilicon quaternary ammonium salt; wherein, the molar ratio of benzyl didodecylamine to γ-chloropropyltrimethoxysilane is 1:(1.0 - 1.6).

[0018] By adopting the above technical solution, the present application uses didodecylamine as a raw material to react with benzyl chloride through a substitution reaction to obtain the intermediate benzyl didodecylamine, and then synthesizes an organosilicon quaternary ammonium salt containing double long chains and benzyl groups by quaternization reaction of benzyl didodecylamine with γ-chloropropyltrimethoxysilane. This organosilicon quaternary ammonium salt has stronger bactericidal performance compared with the single long-chain organosilicon quaternary ammonium salt, and can greatly improve the antibacterial ability of the polypropylene composite material.

[0019] In the second aspect, a preparation method of a polypropylene composite material for a high-performance and low-cost toilet lid provided by the present application adopts the following technical solution: A preparation method of a polypropylene composite material for a high-performance and low-cost toilet lid includes the following steps: S1. Mix polypropylene and white oil and stir until the surface of polypropylene is wetted by white oil, then add the composite filler and continue mixing and stirring, and then add SEBS toughening agent, β-crystal nucleating agent, silver-loaded zinc zeolite antibacterial agent, organosilicon quaternary ammonium salt, and other additives and mix them evenly to obtain a mixture; S2. Melt-blend and extrude the mixture, pelletize, and dry to obtain the polypropylene composite material.

[0020] In summary, the present application has the following beneficial technical effects: 1. The polypropylene composite material of the present application not only has high rigidity but also strong toughness, breaking through the bottleneck of "mutual damage between toughness and rigidity" of traditional rigidifying materials; 2. The polypropylene composite material of the present application realizes a dual antibacterial method of contact type and non-contact type, achieving a long-term antibacterial effect and having extremely high antibacterial performance; 3. The preparation method of the polypropylene composite material of the present application has simple steps, is easy to operate, and is suitable for large-scale industrial production. Detailed Embodiments

[0021] The present application will be further described in detail below in conjunction with embodiments.

[0022] Material Sources Unless otherwise specified, the raw materials used in the present application are all commercially available products, among which: SEBS, purchased from Baling Petrochemical, grade YH-502, specific gravity 0.91 g / cm 3 , volatile content 0.5%, hardness 76A, styrene content 30%; Dodecylamine is synthesized from dodecylamine and 1-bromododecane as synthetic raw materials according to the commonly used synthetic methods in the art. The specific preparation method can refer to the following content. Add dodecylamine and 1-bromododecane with a molar ratio of 1:1.2 to an acetonitrile solvent, heat to 81 °C while stirring, then dropwise add 1-bromododecane within 3 h, and then continuously stir and react at 81 °C for 7 h. After the reaction is completed, cool, stand, filter, wash and dry to obtain a white flaky solid, then neutralize it with an alkali solution, and then filter, wash and dry to obtain dodecylamine; 12-Hydroxystearic acid, purchased from Wuhan Kemike Biopharmaceutical Technology Co., Ltd., CAS number 36377-33-0; Toluene diisocyanate, purchased from Shandong Jinghao Chemical Co., Ltd., grade TDI-80, CAS number 26471-62-5; Hyperbranched polyester, purchased from Shanghai Huicheng Biotechnology Co., Ltd., grade Boltorn H20; Polypropylene, melt index 10-15 g / 10 min; Talc powder, mesh number 1250 mesh; calcium carbonate, mesh number 800 mesh; Silver-loaded zinc zeolite antibacterial agent, using 4A zeolite as a carrier, silver ions (Ag + ) and zinc ions (Zn 2+is an antibacterial active ion, prepared by the liquid-phase ion exchange method commonly used in the art; for the specific preparation method, please refer to the following content. Add 4A zeolite powder to the mixed solution of AgNO3 and Zn(NO3)2, and under the conditions of a reaction temperature of 50 °C, a reaction time of 4 h, a pH value of 6 - 8, and stirring, allow the ion exchange reaction to occur fully. After the reaction, perform centrifugal separation. Wash the separated solid with distilled water three times, then dry it at a temperature of 100 °C for 12 h, and then place it in a muffle furnace. Heat it from room temperature to 450 °C at a heating rate of 10 °C / min, keep it warm for 1 h, and then cool it to obtain a silver-loaded zinc zeolite antibacterial agent with a silver content of 0.41 wt% and a zinc content of 3.83 wt%.

[0023] Preparation Example 1.1 The SEBS toughening agent is prepared by the following method: First, dry SEBS in a vacuum oven at 60 °C for 12 h. Then, mix 10 kg of SEBS, 0.25 kg of glycidyl methacrylate, 0.025 kg of diisopropylbenzene peroxide, and 0.5 kg of styrene, and react them at a temperature of 180 °C and a rotation speed of 75 r / min for 3 min. After that, cool and pelletize, then heat and reflux for 1 h, then perform precipitation and washing, then filter three times in acetone, and then vacuum dry at a temperature of 70 °C for 12 h to obtain the SEBS toughening agent.

[0024] Preparation Example 1.2 The SEBS toughening agent is prepared by the following method: First, dry SEBS in a vacuum oven at 60 °C for 12 h. Then, mix 10 kg of SEBS, 0.3 kg of glycidyl methacrylate, 0.03 kg of diisopropylbenzene peroxide, and 0.6 kg of styrene, and react them at a temperature of 190 °C and a rotation speed of 70 r / min for 5 min. After that, cool and pelletize, then heat and reflux for 1 h, then perform precipitation and washing, then filter three times in acetone, and then vacuum dry at a temperature of 70 °C for 12 h to obtain the SEBS toughening agent.

[0025] Preparation Example 1.3 The SEBS toughening agent is prepared by the following method: First, dry SEBS in a vacuum oven at 60 °C for 12 h. Then, mix 10 kg of SEBS, 0.35 kg of glycidyl methacrylate, 0.035 kg of diisopropylbenzene peroxide, and 0.7 kg of styrene, and react them at a temperature of 200 °C and a rotation speed of 65 r / min for 7 min. After that, cool and pelletize, then heat and reflux for 1 h, then perform precipitation and washing, then filter three times in acetone, and then vacuum dry at a temperature of 70 °C for 12 h to obtain the SEBS toughening agent.

[0026] Preparation Example 1.4 The difference from Preparation Example 1.2 is that glycidyl methacrylate is replaced by maleic anhydride, and the amount of maleic anhydride used is 0.3 kg, and the rest is the same as Preparation Example 1.2.

[0027] Preparation Example 1.5 The difference from Preparation Example 1.2 is that glycidyl methacrylate is replaced by a mixture of maleic anhydride and glycidyl methacrylate, wherein the amount of maleic anhydride used is 0.15 kg, and the amount of glycidyl methacrylate used is 0.15 kg, and the rest is the same as Preparation Example 1.2.

[0028] Preparation Example 2.1 The organosilicon quaternary ammonium salt is prepared by the following method: I. Heat 5 mol of didodecylamine and 70 L of anhydrous acetonitrile to reflux, then add 5 mol of benzyl chloride and continue refluxing for 18 h, then cool to room temperature, filter by suction, and wash the filter cake with distilled water to obtain benzyl didodecylamine; II. Dissolve 5 mol of benzyl didodecylamine in 70 L of ethylene glycol, then add 5 mol of γ-chloropropyltrimethoxysilane at a temperature of 105 °C and react under constant temperature and closed conditions for 44 h, then evaporate, cool to room temperature, filter, wash the filter cake with distilled water, and dry to obtain the organosilicon quaternary ammonium salt.

[0029] Preparation Example 2.2 The organosilicon quaternary ammonium salt is prepared by the following method: I. Heat 5 mol of didodecylamine and 70 L of anhydrous acetonitrile to reflux, then add 6 mol of benzyl chloride and continue refluxing for 20 h, then cool to room temperature, filter by suction, and wash the filter cake with distilled water to obtain benzyl didodecylamine; II. Dissolve 5 mol of benzyl didodecylamine in 70 L of ethylene glycol, then add 7 mol of γ-chloropropyltrimethoxysilane at a temperature of 110 °C and react under constant temperature and closed conditions for 45 h, then evaporate, cool to room temperature, filter, wash the filter cake with distilled water, and dry to obtain the organosilicon quaternary ammonium salt.

[0030] Preparation Example 2.3 The organosilicon quaternary ammonium salt is prepared by the following method: I. Heat 5 mol of didodecylamine and 70 L of anhydrous acetonitrile to reflux, then add 7 mol of benzyl chloride and continue refluxing for 22 h, then cool to room temperature, filter by suction, and wash the filter cake with distilled water to obtain benzyl didodecylamine; II. Dissolve 5 mol of benzyl dodecylamine in 70 L of ethylene glycol, then add 8 mol of γ-chloropropyltrimethoxysilane at a temperature of 115 °C and react under constant temperature and closed conditions for 46 h. After evaporation, cool to room temperature, filter, wash the filter cake with distilled water, and dry to obtain the organosilicon quaternary ammonium salt.

[0031] Preparation Example 3.1 The dispersant is prepared by the following method: a. Dissolve 2.8 kg of 12-hydroxystearic acid in acetone, then add 0.0005 kg of dibutyltin dilaurate and heat to 50 °C, and then add 1.7 kg of toluene diisocyanate and react at a constant temperature for 1.5 h; b. Dissolve 10 kg of hyperbranched polyester in N,N-dimethylformamide, then mix it with the product obtained in step a, heat to 85 °C, and react under reflux condensation for 5 h. Then stop the reaction and distill under reduced pressure to obtain the dispersant.

[0032] Preparation Example 3.2 The dispersant is prepared by the following method: a. Dissolve 3.2 kg of 12-hydroxystearic acid in acetone, then add 0.0015 kg of dibutyltin dilaurate and heat to 60 °C, and then add 1.8 kg of toluene diisocyanate and react at a constant temperature for 2.5 h; b. Dissolve 11 kg of hyperbranched polyester in N,N-dimethylformamide, then mix it with the product obtained in step a, heat to 95 °C, and react under reflux condensation for 7 h. Then stop the reaction and distill under reduced pressure to obtain the dispersant.

[0033] Example 1.1 A preparation method of a high-performance and low-cost polypropylene composite material for toilet lids, comprising the following steps: S1. Mix 70 kg of polypropylene and white oil in a high-speed mixer and stir until the surface of the polypropylene is wetted by the white oil. Then add 25 kg of a composite filler (16.67 kg of talc and 8.33 kg of calcium carbonate) and continue to mix and stir. Then add 5 kg of the SEBS toughening agent prepared in Preparation Example 1.1, 0.3 kg of a β-crystal nucleating agent (0.09 kg of pimelic acid, 0.21 kg of calcium stearate), 1 kg of a silver-loaded zinc zeolite antibacterial agent, 1 kg of the organosilicon quaternary ammonium salt prepared in Preparation Example 2.1, and 0.5 kg of other additives (0.1 kg of antioxidant 1010 and 0.4 kg of lubricant calcium stearate) and mix evenly to obtain a mixture; S2. Melt and blend the mixture through a twin-screw extruder and extrude it. The temperature of each section of the twin-screw is 180-210 °C. Then, after water strand pelletization, dry to obtain the polypropylene composite material.

[0034] Example 1.2 A preparation method of a polypropylene composite material for a high-performance and low-cost toilet lid, comprising the following steps: S1. Mix 75 kg of polypropylene and white oil in a high-speed mixer and stir until the surface of the polypropylene is wetted by the white oil. Then add 20 kg of a composite filler (8.89 kg of talcum powder and 11.11 kg of calcium carbonate) and continue to mix and stir. After that, add 6.5 kg of the SEBS toughening agent prepared in Preparation Example 1.2, 0.2 kg of a β-crystal nucleating agent (0.0522 kg of pimelic acid, 0.1478 kg of calcium stearate), 1.5 kg of a silver-loaded zinc zeolite antibacterial agent, 0.75 kg of the organosilicon quaternary ammonium salt prepared in Preparation Example 2.2, and 0.75 kg of other additives (0.2 kg of antioxidant 1010 and 0.55 kg of lubricant calcium stearate), and mix evenly to obtain a mixed material; S2. Melt-blend and extrude the mixed material through a twin-screw extruder. The temperature of each section of the twin-screw is 180 - 210 °C. Then, after water strand pelletization, dry it to obtain the polypropylene composite material.

[0035] Example 1.3 A preparation method of a polypropylene composite material for a high-performance and low-cost toilet lid, comprising the following steps: S1. Mix 80 kg of polypropylene and white oil in a high-speed mixer and stir until the surface of the polypropylene is wetted by the white oil. Then add 15 kg of a composite filler (5 kg of talcum powder and 10 kg of calcium carbonate) and continue to mix and stir. After that, add 8 kg of the SEBS toughening agent prepared in Preparation Example 1.3, 0.1 kg of a β-crystal nucleating agent (0.023 kg of pimelic acid, 0.077 kg of calcium stearate), 2 kg of a silver-loaded zinc zeolite antibacterial agent, 0.5 kg of the organosilicon quaternary ammonium salt prepared in Preparation Example 2.3, and 1 kg of other additives (0.3 kg of antioxidant 1010 and 0.7 kg of lubricant calcium stearate), and mix evenly to obtain a mixed material; S2. Melt-blend and extrude the mixed material through a twin-screw extruder. The temperature of each section of the twin-screw is 180 - 210 °C. Then, after water strand pelletization, dry it to obtain the polypropylene composite material.

[0036] Example 2.1 A preparation method of a polypropylene composite material for a high-performance and low-cost toilet lid, which is different from Example 1.2 in that: the SEBS toughening agent prepared in Preparation Example 1.2 is replaced with the SEBS toughening agent prepared in Preparation Example 1.4, and the rest are the same as Example 1.2.

[0037] Example 2.2 A preparation method of a polypropylene composite material for a high-performance and low-cost toilet lid, which is different from Example 1.2 in that: the SEBS toughening agent prepared in Preparation Example 1.2 is replaced with the SEBS toughening agent prepared in Preparation Example 1.5, and the rest are the same as those in Example 1.2.

[0038] Example 3.1 A preparation method of a polypropylene composite material for a high-performance and low-cost toilet lid, which is different from Example 1.2 in that: in 0.2 kg of β-crystalline nucleating agent, pimelic acid is 0.15 kg and calcium stearate is 0.05 kg, and the rest are the same as those in Example 1.2.

[0039] Example 3.2 A preparation method of a polypropylene composite material for a high-performance and low-cost toilet lid, which is different from Example 1.2 in that: in 0.2 kg of β-crystalline nucleating agent, pimelic acid is 0.12 kg and calcium stearate is 0.08 kg, and the rest are the same as those in Example 1.2.

[0040] Example 4.1 A preparation method of a polypropylene composite material for a high-performance and low-cost toilet lid, which is different from Example 1.2 in that: before adding the composite filler, first stir 20 kg of the composite filler and 1.4 kg of the dispersant prepared in Example 3.1 in a high-speed mixer for 3 min to obtain a pretreated composite filler, and then mix it with polypropylene and other components, and the rest are the same as those in Example 1.2.

[0041] Example 4.2 A preparation method of a polypropylene composite material for a high-performance and low-cost toilet lid, which is different from Example 1.2 in that: before adding the composite filler, first stir 20 kg of the composite filler and 1.6 kg of the dispersant prepared in Example 3.2 in a high-speed mixer for 3 min to obtain a pretreated composite filler, and then mix it with polypropylene and other components, and the rest are the same as those in Example 1.2.

[0042] Example 4.3 A preparation method of a polypropylene composite material for a high-performance and low-cost toilet lid, which is different from Example 1.2 in that: before adding the composite filler, first mix 20 kg of the composite filler and 1.6 kg of stearic acid, and stir at a speed of 30 r / min at a temperature of 110 °C for 10 min, and then cool to 30 °C to obtain a pretreated composite filler, and then mix it with polypropylene and other components, and the rest are the same as those in Example 1.2.

[0043] Example 4.4 A preparation method of a polypropylene composite material for a high-performance and low-cost toilet lid, which is different from Examples 1.2 in that: before adding the composite filler, 20 kg of the composite filler and 1.6 kg of aluminate coupling agent are first mixed, and stirred at a speed of 30 r / min at a temperature of 110 °C for 10 min, and then cooled to 30 °C to obtain a pretreated composite filler and then mixed with components such as polypropylene, and the rest are the same as in Examples 1.2.

[0044] Examples 4.5 A preparation method of a polypropylene composite material for a high-performance and low-cost toilet lid, which is different from Examples 1.2 in that: before adding the composite filler, 20 kg of the composite filler, 0.8 kg of stearic acid and 0.8 kg of aluminate coupling agent are first mixed, and stirred at a speed of 30 r / min at a temperature of 110 °C for 10 min, and then cooled to 30 °C to obtain a pretreated composite filler and then mixed with components such as polypropylene, and the rest are the same as in Examples 1.2.

[0045] Comparative Example 1.1 The difference from Examples 1.2 is that: the SEBS toughening agent and β-crystal form nucleating agent prepared in Preparation Example 1.2 are not added, and the rest are the same as in Examples 1.2.

[0046] Comparative Example 1.2 The difference from Examples 1.2 is that: 6.5 kg of the SEBS toughening agent and 0.2 kg of the β-crystal form nucleating agent prepared in Preparation Example 1.2 are replaced with 6.7 kg of a POE toughening agent, purchased from ExxonMobil, USA, grade 6102, and the rest are the same as in Examples 1.2.

[0047] Comparative Example 1.3 The difference from Examples 1.2 is that: 6.5 kg of the SEBS toughening agent prepared in Preparation Example 1.2 is replaced with an ungrafted modified SEBS toughening agent, and the rest are the same as in Examples 1.2.

[0048] Comparative Example 1.4 The difference from Examples 1.2 is that: 6.5 kg of the SEBS toughening agent and 0.2 kg of the β-crystal form nucleating agent prepared in Preparation Example 1.2 are replaced with 6.7 kg of the SEBS toughening agent prepared in Preparation Example 1.2, and the rest are the same as in Examples 1.2.

[0049] Comparative Example 1.5 The difference from Examples 1.2 is that: 6.5 kg of the SEBS toughening agent and 0.2 kg of the β-crystal form nucleating agent are replaced with 6.7 kg of the β-crystal form nucleating agent (1.7478 kg of pimelic acid, 4.9522 kg of calcium stearate), and the rest are the same as in Examples 1.2.

[0050] Comparative Example 2.1 The difference from Example 1.2 is that 1.5 kg of silver-loaded zinc zeolite antibacterial agent and 0.75 kg of the organosilicon quaternary ammonium salt prepared in Preparation Example 2.2 are replaced with 2.25 kg of silver-loaded zinc zeolite antibacterial agent, and the rest is the same as Example 1.2.

[0051] Comparative Example 2.2 The difference from Example 1.2 is that 1.5 kg of silver-loaded zinc zeolite antibacterial agent and 0.75 kg of the organosilicon quaternary ammonium salt prepared in Preparation Example 2.2 are replaced with 2.25 kg of the organosilicon quaternary ammonium salt prepared in Preparation Example 2.2, and the rest is the same as Example 1.2.

[0052] Comparative Example 2.3 The difference from Example 1.2 is that the organosilicon quaternary ammonium salt prepared in Preparation Example 2.2 is replaced with 3-(trimethoxysilylpropyl)dimethyloctadecylammonium chloride, CAS No. 27668-52-6, and the rest is the same as Example 1.2.

[0053] Performance Testing 1. The composite materials prepared in the above examples and comparative examples were injection molded and then tested for relevant mechanical properties. The injection molding temperature was 180°C and the injection pressure was 60 MPa. The relevant mechanical properties mainly included tensile properties, impact properties, and flexural properties. Among them, the tensile properties were tested using an electronic universal testing machine, referring to the standard of GB / T 1040.1-2006, the tensile speed was 50 mm / min, 5 specimens were tested in each group, the specimen size was 170 mm × 10 mm × 4 mm, and the average value of the specimens was taken as the test result. The impact properties were tested using a digital display cantilever beam impact testing machine, referring to the standard of GB / T 1843-2008, the pendulum energy was 2.75 J, 7 specimens were tested in each group, the specimen size was 80 mm × 10 mm × 4 mm, and the average value of the specimens was taken as the test result. The flexural properties were tested using an electronic universal testing machine, referring to the standard of GB / T 9341-2008, the test speed was 2 mm / min, the deflection was 6 mm, 5 specimens were tested in each group, the specimen size was 80 mm × 10 mm × 4 mm, and the average value of the specimens was taken as the test result. The above test results were all recorded in Table 1. Among them, since Comparative Examples 2.1-2.3 mainly investigated the antibacterial properties of the composite materials and there were no significant differences in mechanical properties, they were not recorded in Table 1.

[0054] 2. The composite materials prepared in Example 1.2 and Comparative Examples 2.1 - 2.3 were injection - molded, and then relevant antibacterial performance tests were carried out with reference to ISO 22196 - 2011 "Evaluation Method for Antibacterial Activity on the Surface of Plastic Products", and the results were recorded in Table 2. The test bacteria included Staphylococcus aureus and Escherichia coli.

[0055] Table 1 Test Results of Mechanical Properties Table 2 Test Results of Antibacterial Properties Unit: % Project Staphylococcus aureus Escherichia coli Example 1.2 99.99 99.99 Comparative Example 2.1 99.35 99.41 Comparative Example 2.2 99.76 99.81 Comparative Example 2.3 99.77 99.78 As can be seen from Table 1, the tensile strength of the polypropylene composite materials prepared in Examples 1.1 - 1.3 of this application is 32.4 - 37.5 MPa, the notched impact strength is 8.0 - 8.5 KJ / m 2 , the flexural strength is 43.2 - 50.4 MPa, and the flexural modulus is 1930 - 2100 MPa. This shows that the polypropylene composite materials prepared in this application can simultaneously have relatively high flexural modulus and impact strength, breaking through the bottleneck of the "rigidity - toughness" mutual loss of traditional rigidifying materials. Moreover, as can be seen from Table 2, the antibacterial rates of the polypropylene composite materials prepared in Example 1.2 of this application against Staphylococcus aureus and Escherichia coli can reach 99.99%, with extremely high antibacterial performance. At the same time, after being washed 200 times, the antibacterial rate can still remain above 99.9%.

[0056] The differences between Examples 2.1 - 2.2 and Example 1.2 lie in that during the preparation process of the used SEBS toughening agent, maleic anhydride or a mixture of maleic anhydride and glycidyl methacrylate was used to replace glycidyl methacrylate for the reaction. As can be seen from Table 1, the test results of Examples 2.1 - 2.2 are generally worse than those of Example 1.2, especially in terms of toughness. This shows that compared with using maleic anhydride as the graft monomer or using a mixture of maleic anhydride and glycidyl methacrylate as the graft monomer, Example 1.2 using glycidyl methacrylate as the graft monomer can make the prepared SEBS toughening agent have better toughening effect, thus improving the toughness of the polypropylene composite material.

[0057] Examples 3.1 - 3.2 are different from Example 1.2 in that the content of calcium stearate in the used β - crystal nucleating agent is too low. As can be seen from Table 1, the detection results of Examples 3.1 - 3.2 are overall worse than those of Example 1.2, and both the rigidity and toughness are significantly reduced. This shows that if the addition amount of calcium stearate is too small, it cannot fully undergo a chemical reaction when mixed and melted with polypropylene to generate the highly efficient β - crystal nucleating agent calcium pimelate, thereby reducing its ability to induce the formation of β - crystals in polypropylene, and further reducing the overall performance of the polypropylene composite material.

[0058] Examples 4.1 - 4.5 are different from Example 1.2 in that a dispersant is used to pretreat the composite filler. As can be seen from Table 1, the rigidity of Examples 4.1 - 4.5 is significantly stronger than that of Example 1.2, and the toughness loss is smaller. This shows that the addition of the dispersant can fully improve the dispersibility of the composite filler in the polypropylene matrix and make the components have good compatibility, thereby further enhancing the rigidity of the polypropylene composite material with less toughness loss.

[0059] Among them, by comparing the data between Examples 4.1 - 4.5, it can be found that compared with using other dispersants or modifiers, the dispersing effect of the dispersant prepared by Preparation Examples 3.1 - 3.2 in Examples 4.1 - 4.2 is better, and the performance of the finally prepared polypropylene composite material is better.

[0060] Comparative Example 1.1 is different from Example 1.2 in that no toughening agent is added. As can be seen from Table 1, the detection results of Comparative Example 1.1 are worse than those of Example 1.2, especially the impact strength is significantly lower than that of Example 1.2. This shows that if no toughening agent is added, the toughness of the polypropylene composite material will be significantly deteriorated.

[0061] Comparative Example 1.2 is different from Example 1.2 in that a traditional POE toughening agent is used to replace the SEBS toughening agent + β - crystal nucleating agent system of the present application. As can be seen from Table 1, the detection results of Comparative Example 1.2 are worse than those of Example 1.2. This shows that although the POE toughening agent can achieve a toughening effect, due to its flexible chain segments, it will significantly reduce the rigidity of the polypropylene composite material.

[0062] Comparative Example 1.3 is different from Example 1.2 in that a common SEBS toughening agent is used. As can be seen from Table 1, the detection results of Comparative Example 1.3 are worse than those of Example 1.2. This shows that graft - modifying the SEBS toughening agent can significantly improve the compatibility of the SEBS toughening agent with components such as polypropylene, thereby improving its toughening effect on the polypropylene composite material.

[0063] Comparative Example 1.4 - 1.5 is different from Example 1.2 in that only one of SEBS toughening agent and β - crystal nucleating agent is used. As can be seen from Table 1, the test results of Comparative Example 1.4 - 1.5 are worse than those of Example 1.2. This shows that using SEBS toughening agent and β - crystal nucleating agent in combination can give full play to the synergistic toughening effect between them, thereby improving the toughness of the polypropylene composite material.

[0064] Comparative Example 2.1 - 2.2 is different from Example 1.2 in that only one of silver - loaded zeolite antibacterial agent and organosilicon quaternary ammonium salt is used. As can be seen from Table 2, the antibacterial rate of Comparative Example 2.1 - 2.2 is lower than that of Example 1.2. This shows that using silver - loaded zeolite antibacterial agent and organosilicon quaternary ammonium salt in combination can give full play to the synergistic antibacterial effect between them, thereby improving the antibacterial performance of the polypropylene composite material.

[0065] Comparative Example 2.3 is different from Example 1.2 in that a single - long - chain organosilicon quaternary ammonium salt is used. As can be seen from Table 2, the antibacterial rate of Comparative Example 2.3 is worse than that of Example 1.2. This shows that using a double - long - chain benzyl - containing organosilicon quaternary ammonium salt can further improve the antibacterial performance of the polypropylene composite material.

[0066] The embodiments of this specific implementation manner are all preferred embodiments of this application, and do not limit the protection scope of this application accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A high-performance and low-cost polypropylene composite material for toilet lids, characterized in that: The raw materials used include the following components in parts by weight: Polypropylene 70-80 parts; 15-25 parts of composite filler; SEBS toughening agent 5-8 parts; β-crystal nucleating agent 0.1-0.3 parts; 1-2 parts of silver-zinc zeolite antibacterial agent; 0.5-1.0 part of organosilicon quaternary ammonium salt; Other additives 0.5-1.0 part.

2. The high-performance and low-cost polypropylene composite material for toilet seats according to claim 1, characterized in that: The composite filler comprises talcum powder and calcium carbonate in a weight ratio of 1:(0.5-2.0).

3. The high-performance and low-cost polypropylene composite material for toilet seats according to claim 1, characterized in that: The SEBS toughening agent is prepared by the following method: SEBS, glycidyl methacrylate, dicumyl peroxide and styrene in a weight ratio of 100: (2.5-3.5): (0.25-0.35): (5-7) are mixed, and then reacted at a temperature of 180-200°C and a rotation speed of 65-75r / min for 3-7 minutes, and then cooled and pelletized, and then post-processed and purified to obtain a SEBS toughening agent.

4. The high-performance and low-cost polypropylene composite material for toilet seats according to claim 1, characterized in that: The β-crystal nucleating agent comprises pimelic acid and calcium stearate in a weight ratio of 3:(7-10).

5. The high-performance and low-cost polypropylene composite material for toilet seats according to claim 1, characterized in that: The raw materials also include 1.4-1.6 parts by weight of a dispersant.

6. The high-performance and low-cost polypropylene composite material for toilet seats according to claim 5, characterized in that: The dispersant is prepared by the following method: a. Dissolve 28-32 parts by weight of 12-hydroxystearic acid in acetone, then add 0.005-0.015 parts by weight of dibutyltin dilaurate and heat to 50-60° C., then add 17-18 parts by weight of toluene diisocyanate and react at constant temperature for 1.5-2.5 hours; b. Dissolve 100-110 parts by weight of the hyperbranched polyester in N,N-dimethylformamide, mix with the product obtained in step a, heat to 85-95° C., condense and reflux for 5-7 hours, then stop the reaction and perform vacuum distillation to obtain a dispersant.

7. The high-performance and low-cost polypropylene composite material for toilet seats according to claim 1, characterized in that: The organosilicon quaternary ammonium salt is prepared by the following method: I. Heating dilaurylamine and anhydrous acetonitrile to reflux, then adding benzyl chloride to continue reflux reaction for 18-22 hours, then cooling to room temperature, filtering, washing, and obtaining benzyldilaurylamine; wherein the molar ratio of dilaurylamine to benzyl chloride is 1:(1.0-1.4); II. Dissolve benzyldidodecylamine in ethylene glycol, then add γ-chloropropyltrimethoxysilane at 105-115°C and react in a closed manner for 44-46 hours at a constant temperature, followed by evaporation, cooling, filtering, washing and drying to obtain an organosilicon quaternary ammonium salt; wherein the molar ratio of benzyldidodecylamine to γ-chloropropyltrimethoxysilane is 1:(1.0-1.6).

8. A method for preparing the high-performance and low-cost polypropylene composite material for toilet seats according to claim 1, characterized in that: The following steps are involved: S1, mixing polypropylene and white oil and stirring until the surface of polypropylene is wetted by the white oil, then adding the composite filler and continuing to mix and stir, and then adding SEBS toughening agent, β crystal nucleating agent, silver-zinc zeolite antibacterial agent, organosilicon quaternary ammonium salt and other additives and mixing evenly to obtain a mixture; S2, melt-blending and extruding the mixed materials, pelletizing, and drying to obtain a polypropylene composite material.

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