High-rigidity high-toughness seat pp composite material and preparation method thereof

Abstract

The application relates to the technical field of high polymer materials, in particular to a high-rigidity and high-toughness seat PP composite material and a preparation method thereof, which comprises the following components: 30-50 parts by weight of polypropylene, 10-25 parts by weight of high-density polyethylene, 3-6 parts by weight of linear low-density polyethylene grafting material, 10-20 parts by weight of inorganic fillers, 5-10 parts by weight of alkali-free glass fibers, 0.3-0.6 parts by weight of a coupling agent, 1-2 parts by weight of a macromolecular dispersing agent and 0.2-0.5 parts by weight of an antioxidant; wherein the linear low-density polyethylene grafting material is prepared by mixing linear low-density polyethylene, 3-(vinyl oxy) prop-1-amine and mesitylic acid according to a mass ratio of 10:0.1-0.5:2-3. The linear low-density polyethylene grafting, the medium-alkali glass fibers and the composite inorganic fillers are synergistically used, so that the prepared polypropylene composite material has high rigidity and high toughness, and the prepared protective seat meets the requirements of excellent rigidity, good resilience and poor deformation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a high-rigidity and high-toughness seat PP composite material and a preparation method thereof. BACKGROUND

[0002] Polypropylene (PP) is a thermoplastic resin prepared by polymerization of propylene, which has the characteristics of non-toxic, odorless, small density, strength, rigidity, hardness and heat resistance better than low-pressure polyethylene, and can be used at about 100 DEG C. In addition, polypropylene also has good dielectric properties and high-frequency insulation, and is not affected by humidity. These characteristics make polypropylene have a wide application prospect in seat manufacturing. For example, polypropylene is a commonly used raw material for preparing seats. When preparing a protective seat, it is required to have certain rigidity, stiffness and resilience, and the product also needs to have the dual characteristics of anti-falling fracture and anti-gravity fracture. Therefore, the PP composite material needs to have high rigidity, strength and resilience. However, pure polypropylene still has deficiencies in rigidity and toughness. In view of this, the present application provides a high-rigidity and high-toughness seat PP composite material and a preparation method thereof. SUMMARY

[0003] The present application aims to provide a high-rigidity and high-toughness seat PP composite material and a preparation method thereof to solve the problems in the background.

[0004] To achieve the above-mentioned purpose, on the one hand, the present application provides a high-rigidity and high-toughness seat PP composite material, which comprises the following components: polypropylene 30-50 parts by weight, high-density polyethylene 10-25 parts by weight, linear low-density polyethylene grafting material 3-6 parts by weight, inorganic filler 10-20 parts by weight, alkali-free glass fiber 5-10 parts by weight, coupling agent 0.3-0.6 parts by weight, macromolecular dispersing agent 1-2 parts by weight and antioxidant 0.2-0.5 parts by weight.

[0005] The linear low-density polyethylene grafting material is prepared by mixing linear low-density polyethylene, 3-(vinyl oxy) propyl-1-amine and mesitylic acid at a mass ratio of 10:0.1-0.5:2-3.

[0006] The macromolecular dispersing agent is obtained by mixing maleic anhydride grafted polypropylene and 3-(urea amino) propyl triethoxysilane at a mass ratio of 1:1.5-1.7.

[0007] The carboxyl group on the maleic anhydride grafted polypropylene reacts with the amino group on the 3-(urea amino) propyl triethoxysilane to form an amide bond, so that the macromolecular dispersing agent contains siloxane groups which can be compatible with inorganic materials, carboxyl groups on maleic anhydride and amino groups on 3-(urea amino) propyl triethoxysilane. At the same time, it is based on polypropylene macromolecule, so it has good compatibility with polypropylene composite material.

[0008] The macromolecular dispersant can better promote the coupling and binding of the inorganic filler, alkali-free glass fiber and the polypropylene base material, improve the micro compatibility, enable the prepared polypropylene composite material to have high rigidity and high toughness, has strong affinity to the inorganic filler, enables the inorganic filler to be fully activated and modified, destroys and prevents the agglomeration of the inorganic filler, and thus is more uniformly dispersed in the polymer, so that the addition amount of the filler can be increased, and the effect of toughening and reinforcing is achieved by relying on the strong interfacial bonding; when applied to the processing of the polymer composite material, the macromolecular dispersant can well improve the compatibility of the components in the system, promote plasticization, reduce the melt viscosity, improve the processing fluidity, reduce the torque of the processing equipment, reduce the processing energy consumption, improve the production efficiency, and can improve the mechanical properties such as impact strength and elongation at break of the product, and significantly improve the surface gloss performance of the product; the macromolecular dispersant has a multi-functional structure with a high-activity anchor group, the surface of the filler particles is modified by multi-point adsorption of the anchor group and chemical reaction at the same time, complete surface chemical reaction coating is achieved, the surface of the filler is organic, so that the surface energy of the filler is effectively reduced, in addition, the long polymer chains in the macromolecule of the product have strong affinity and compatibility with the base polymer material, so that the processing performance of the composite material system is greatly improved, and the physical properties are not affected.

[0009] As a preferred, the inorganic filler is one or more combinations of calcium carbonate, talc powder, mica powder, wollastonite, kaolin, magnesium hydroxide and aluminum hydroxide.

[0010] As a preferred, the coupling agent is one or more combinations of γ-aminopropyl triethoxysilane, vinyl trimethoxysilane and bis(dioctyl pyrophosphoryl) titanium diisopropylate.

[0011] As a preferred, the antioxidant is one or more combinations of 3,5-di-tert-butyl-4-hydroxyphenyl propionic acid n-octadecyl ester, tris[2.4-di-tert-butylphenyl] phosphite and didodecyl thiodipropionate.

[0012] As a preferred, the preparation method of the linear low density polyethylene graft is as follows:

[0013] The linear low density polyethylene, 3-(vinyl oxy) propyl-1-amine and dicumyl peroxide are put into a high-speed mixer, mixed uniformly at room temperature, to ensure that the components are uniformly distributed, and then the mixed material is added into an internal mixer, with a temperature setting of 160-190℃ and a rotation speed of 40-50rpm, and the mixing time is 15-20min; after the mixing is completed, the product is immediately taken out and rapidly cooled to obtain the preliminary modified linear low density polyethylene; the preliminary modified linear low density polyethylene, erucic acid, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, 4-dimethylaminopyridine and triethylamine are again put into the internal mixer, with a reaction temperature setting of 150-170℃ and a holding time of 1-2h; after the reaction is completed, the product is immediately taken out and rapidly cooled, and then the product is made into a pellet to obtain the linear low density polyethylene grafting product.

[0014] The 3-(vinyl oxy) propyl-1-amine is grafted with the linear low density polyethylene, the introduced amino group can provide polarity to the linear low density polyethylene, and through the formation of hydrogen bonds, the intermolecular interaction of the linear low density polyethylene is enhanced, and the impact resistance and elongation at break of the linear low density polyethylene material are improved, thereby improving the impact resistance and elongation at break of the polypropylene composite material; at the same time, the polar characteristics of the amino group can also improve the interaction force between the linear low density polyethylene and the alkali-free glass fiber and the inorganic filler, and through the formation of hydrogen bonds between the amino group and the surface of the inorganic filler, the compatibility problem between the linear low density polyethylene and the alkali-free glass fiber and the inorganic filler is improved, and the problem of incompatibility with the alkali-free glass fiber is avoided; however, the hydrogen bond has a small force, especially under high temperature or stress conditions, in order to further enhance the force between the linear low density polyethylene and the alkali-free glass fiber, the erucic acid is introduced to extend the length of the branched chain, and through the formation of a winding and coating effect, the alkali-free glass fiber is coated, thereby further enhancing the mechanical properties of the composite material, and the polypropylene composite material has better elongation at break and resilience characteristics.

[0015] As preferred, the dicumyl peroxide accounts for 0.5-2% of the mass of the linear low density polyethylene; and the molar ratio of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, 4-dimethylaminopyridine, triethylamine and erucic acid is 1-1.5:0.1-0.5:1:1.

[0016] As preferred, the preparation method of the macromolecular dispersant is as follows:

[0017] Maleic anhydride grafted polypropylene is dissolved in dichloromethane to prepare a 3-8% w / v solution, 4-dimethylaminopyridine is added to obtain a mixed solution, wherein the addition amount of dimethylaminopyridine is 0.1-5% of the mass of maleic anhydride grafted polypropylene, 3-(urea amino) propyl triethoxysilane is added dropwise into the mixed solution under the protection of nitrogen, while stirring, the reaction mixture is heated to 60-80℃, the reaction time is 4-6h, after the reaction is completed, the solvent is removed by a rotary evaporator to obtain a macromolecular dispersant.

[0018] In another aspect, the application provides a preparation method of high-rigidity and high-toughness seat PP composite material, for preparing the high-rigidity and high-toughness seat PP composite material, comprising the following steps:

[0019] Polypropylene, high-density polyethylene and linear low-density polyethylene graft are added into a high-speed mixer, then a coupling agent, an inorganic filler, a macromolecular dispersant and an antioxidant are added and mixed fully, finally, alkali-free glass fiber is added and mixed until uniform, the mixed material is melt-blended by using a twin-screw extruder, a temperature curve is set, a shear rate and a residence time are controlled, finally, the composite material is extruded by an injection molding machine to obtain the high-rigidity and high-toughness seat PP composite material.

[0020] The alkali-free glass fiber contains lower sodium oxide and calcium oxide contents, which makes it have better hydrolysis resistance and chemical corrosion resistance, especially better stability in a humid or acidic environment, the tensile strength and elastic modulus of the alkali-free glass fiber are better than those of common glass fiber, which can provide stronger reinforcing effect, and the alkali-free glass fiber has better heat resistance, which can keep its physical and mechanical properties unchanged in a wider temperature range and has better stability; a protective seat needs to have certain rigidity, stiffness and resilience, and also needs to have the dual characteristics of anti-falling fracture and anti-gravity fracture, so the polypropylene composite material needs to have higher rigidity, strength, resilience, toughness and elongation at break, however, common glass fiber reinforced polypropylene can improve the mechanical properties of the seat to a certain extent, but has low elongation at break, so the obtained seat is easy to break when falling, therefore, the alkali-free glass fiber is used and the branched linear low-density polyethylene graft is used to obtain the winding and coating effect, so that the prepared polypropylene composite material has higher elongation at break while having high rigidity, thereby having better toughness and anti-falling property.

[0021] Preferably, the temperature curve is divided into four parts of a feeding zone, a plasticizing zone, a homogenizing zone and an outlet zone, the temperature of the feeding zone is controlled at 160-180℃, the temperature of the plasticizing zone is controlled at 190-210℃, the temperature of the homogenizing zone is controlled at 200-220℃, and the temperature of the outlet zone is controlled at 205-225℃.

[0022] Preferably, the shear rate is 300-600 s -1 , the residence time is 1-5 min.

[0023] Compared with the prior art, the application has the following beneficial effects:

[0024] In the high-rigidity and high-toughness seat PP composite material and the preparation method thereof, the linear low-density polyethylene grafting material can enhance the interfacial interaction between polypropylene and linear low-density polyethylene and improve the compatibility of the two, thereby improving the elongation at break of the material and enhancing the rigidity of the composite material, and the composite material has better toughness and drop resistance. In addition, the use of alkali-free glass fiber instead of ordinary glass fiber can provide stronger reinforcing effect, and the long-chain branches of the linear low-density polyethylene grafting material can wrap and coat the alkali-free glass fiber, thereby enhancing the interaction of the composite material and improving the mechanical properties of the seat. In addition, the use of the macromolecular dispersant can better promote the coupling and combination of the inorganic filler, the alkali-free glass fiber and the polypropylene base material, improve the micro-compatibility, and make the prepared polypropylene composite material have high rigidity and high toughness, thereby meeting the requirements that the prepared protective seat has excellent rigidity, good resilience and is not easy to deform. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the application will be clearly and completely described below in combination with the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0026] The high-rigidity and high-toughness seat PP composite material of the application comprises the following components: polypropylene 30-50 parts by weight, high-density polyethylene 10-25 parts by weight, linear low-density polyethylene grafting material 3-6 parts by weight, inorganic filler 10-20 parts by weight, alkali-free glass fiber 5-10 parts by weight, coupling agent 0.3-0.6 parts by weight, macromolecular dispersant 1-2 parts by weight and antioxidant 0.2-0.5 parts by weight.

[0027] The linear low-density polyethylene grafting material is prepared by mixing linear low-density polyethylene, 3-(vinyl oxy) propyl-1-amine and mesitylic acid at a mass ratio of 10:0.1-0.5:2-3.

[0028] The macromolecular dispersant is obtained by mixing maleic anhydride grafted polypropylene and 3-(urea amino) propyl triethoxysilane at a mass ratio of 1:1.5-1.7.

[0029] Preferably, the inorganic filler is calcium carbonate; the coupling agent is gamma-aminopropyl triethoxysilane; and the antioxidant is tris[2,4-di-tert-butylphenyl] phosphite.

[0030] Embodiment 1: A high-rigidity and high-toughness seat PP composite material and a preparation method thereof, comprising the following steps:

[0031] Preparation of components: 50 parts by weight of polypropylene, 25 parts by weight of high-density polyethylene, 6 parts by weight of linear low-density polyethylene graft, 20 parts by weight of calcium carbonate, 10 parts by weight of non-alkali glass fiber, 0.6 parts by weight of gamma-aminopropyl triethoxysilane, 2 parts by weight of macromolecular dispersant, and 0.5 parts by weight of tris[2,4-di-tert-butylphenyl] phosphite;

[0032] Preferably, the linear low-density polyethylene graft is prepared by mixing linear low-density polyethylene, 3-(vinyl oxy) propyl-1-amine, and mesitylic acid at a mass ratio of 10:0.1:2; and the macromolecular dispersant is obtained by mixing maleic anhydride grafted polypropylene and 3-(urea amino) propyl triethoxysilane at a mass ratio of 1:1.5;

[0033] The content of dicumyl peroxide is 2% of the mass of the linear low-density polyethylene; and the molar ratio of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, 4-dimethylaminopyridine, triethylamine, and erucic acid is 1.5:0.5:1:1;

[0034] The linear low-density polyethylene, 3-(vinyl oxy) propyl-1-amine, and dicumyl peroxide are placed in a high-speed mixer, mixed uniformly at room temperature, and ensured to be uniformly distributed; the mixed material is added to an internal mixer, set to a temperature of 170℃ and a rotation speed of 50 rpm, and mixed for 15 min; after the mixing is completed, the product is immediately taken out and rapidly cooled to obtain the linear low-density polyethylene after preliminary modification; the linear low-density polyethylene after preliminary modification, erucic acid, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, 4-dimethylaminopyridine, and triethylamine are again placed in the internal mixer, set to a reaction temperature of 160℃ and a holding time of 2 h, and after the reaction is completed, the product is immediately taken out and rapidly cooled, and then granulated to obtain the linear low-density polyethylene graft;

[0035] The maleic anhydride grafted polypropylene is dissolved in dichloromethane to prepare a 5% w / v solution, and 4-dimethylaminopyridine is added to obtain a mixed solution, wherein the addition amount of dimethylaminopyridine is 1% of the mass of the maleic anhydride grafted polypropylene; under nitrogen protection, 3-(urea amino) propyl triethoxysilane is added dropwise to the mixed solution while stirring; the reaction mixture is heated to 80℃, and the reaction time is 4 h; after the reaction is completed, the solvent is removed by a rotary evaporator to obtain the macromolecular dispersant;

[0036] The polypropylene, high-density polyethylene and linear low-density polyethylene grafts are added into a high-speed mixer, then a coupling agent, an inorganic filler, a macromolecular dispersant and an antioxidant are added and mixed well, finally, alkali-free glass fibers are added and continue to be mixed until uniform, the mixed materials are melt blended using a twin-screw extruder, a temperature curve is set, a shear rate and a residence time are controlled, wherein the temperature curve is divided into four parts of a feeding zone, a plasticizing zone, a homogenizing zone and an outlet zone, the feeding zone temperature is controlled at 160℃, the plasticizing zone temperature is controlled at 190℃, the homogenizing zone temperature is controlled at 200℃, and the outlet zone temperature is controlled at 225℃, the shear rate is 600s -1 , the residence time is 5min, finally, the composite material is extruded through an injection molding machine to obtain a high-rigidity and high-toughness seat PP composite material.

[0037] Example 2: A high-rigidity and high-toughness seat PP composite material and a preparation method thereof, comprising the following steps:

[0038] Preparation of components: 50 parts by weight of polypropylene, 25 parts by weight of high-density polyethylene, 6 parts by weight of linear low-density polyethylene graft, 20 parts by weight of calcium carbonate, 10 parts by weight of alkali-free glass fiber, 0.6 parts by weight of γ-aminopropyl triethoxysilane, 2 parts by weight of macromolecular dispersant and 0.5 parts by weight of tris[2.4-di-tert-butylphenyl]phosphite;

[0039] The linear low-density polyethylene graft is prepared by mixing linear low-density polyethylene, 3-(vinyl oxy) propyl-1-amine and mesitylic acid at a mass ratio of 10:0.3:2.5; the macromolecular dispersant is prepared by mixing maleic anhydride grafted polypropylene and 3-(urea amino) propyl triethoxysilane at a mass ratio of 1:1.6;

[0040] The dicumyl peroxide accounts for 2% of the mass of the linear low-density polyethylene; the molar ratio of the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, 4-dimethylaminopyridine, triethylamine and erucic acid is 1.5:0.5:1:1;

[0041] The linear low density polyethylene, 3-(vinyl oxy) propyl-1-amine and dicumyl peroxide are put into a high-speed mixer, mixed uniformly at room temperature, to ensure uniform distribution of each component, and then the mixed material is added into an internal mixer, set at a temperature of 170℃ and a rotation speed of 50 rpm, and mixed for 15 min. After the mixing is completed, the product is immediately taken out and rapidly cooled to obtain the preliminary modified linear low density polyethylene. The preliminary modified linear low density polyethylene, erucic acid, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, 4-dimethylaminopyridine and triethylamine are again put into the internal mixer, set at a reaction temperature of 160℃ and a holding time of 2 h, and after the reaction is completed, the product is immediately taken out and rapidly cooled, and then the product is made into a pellet to obtain the linear low density polyethylene grafting product.

[0042] The maleic anhydride grafted polypropylene is dissolved in dichloromethane to prepare a 5% w / v solution, and 4-dimethylaminopyridine is added to obtain a mixed solution, wherein the addition amount of dimethylaminopyridine is 1% of the mass of the maleic anhydride grafted polypropylene. Under the protection of nitrogen, 3-(urea amino) propyl triethoxysilane is added dropwise into the mixed solution while stirring, and the reaction mixture is heated to 80℃. The reaction time is 4 h. After the reaction is completed, the solvent is removed by a rotary evaporator to obtain a macromolecular dispersant.

[0043] The polypropylene, high density polyethylene and linear low density polyethylene grafting product are added into a high-speed mixer, and then the coupling agent, inorganic filler, macromolecular dispersant and antioxidant are added and mixed fully. Finally, the alkali-free glass fiber is added and continuously mixed until uniform. The mixed material is melt blended by using a twin-screw extruder, and a temperature curve is set to control the shear rate and residence time. The temperature curve is divided into four parts of a feeding zone, a plasticizing zone, a homogenizing zone and an outlet zone. The temperature of the feeding zone is controlled at 160℃, the temperature of the plasticizing zone is controlled at 190℃, the temperature of the homogenizing zone is controlled at 200℃, and the temperature of the outlet zone is controlled at 225℃. The shear rate is 600 s -1 , and the residence time is 5 min. Finally, the composite material is extruded by an injection molding machine to obtain a high-rigidity and high-toughness seat PP composite material.

[0044] Example 3: A high-rigidity and high-toughness seat PP composite material and a preparation method thereof, comprising the following steps:

[0045] The components are prepared: 50 parts by weight of polypropylene, 25 parts by weight of high density polyethylene, 6 parts by weight of linear low density polyethylene grafting product, 20 parts by weight of calcium carbonate, 10 parts by weight of alkali-free glass fiber, 0.6 parts by weight of γ-aminopropyl triethoxysilane, 2 parts by weight of macromolecular dispersant and 0.5 parts by weight of tris[2.4-di-tert-butylphenyl] phosphite.

[0046] The linear low density polyethylene graft is prepared by mixing linear low density polyethylene, 3-(vinyl oxy) propyl-1-amine and mesitylic acid in a mass ratio of 10:0.5:3; the macromolecular dispersant is prepared by mixing maleic anhydride grafted polypropylene and 3-(urea amino) propyl triethoxysilane in a mass ratio of 1:1.7;

[0047] The dicumyl peroxide accounts for 2% of the mass of the linear low density polyethylene; the molar ratio of the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, 4-dimethylaminopyridine, triethylamine and erucic acid is 1.5:0.5:1:1;

[0048] The linear low density polyethylene, 3-(vinyl oxy) propyl-1-amine and dicumyl peroxide are put into a high-speed mixer, mixed uniformly at room temperature, and the uniform distribution of the components is ensured, and then the mixed material is added to an internal mixer, the temperature is set to 170℃, the rotating speed is 50rpm, and the mixing time is 15min; after the mixing is completed, the product is immediately taken out and rapidly cooled to obtain the preliminary modified linear low density polyethylene; the preliminary modified linear low density polyethylene, erucic acid, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, 4-dimethylaminopyridine and triethylamine are again put into the internal mixer, the reaction temperature is set to 160℃, and the holding time is 2h; after the reaction is completed, the product is immediately taken out and rapidly cooled, and then the product is made into a pellet to obtain the linear low density polyethylene graft;

[0049] The maleic anhydride grafted polypropylene is dissolved in dichloromethane to prepare a 5%w / v solution, and 4-dimethylaminopyridine is added to obtain a mixed solution, wherein the addition amount of dimethylaminopyridine is 1% of the mass of the maleic anhydride grafted polypropylene; under the protection of nitrogen, 3-(urea amino) propyl triethoxysilane is added dropwise into the mixed solution while stirring, and the reaction mixture is heated to 80℃, and the reaction time is 4h; after the reaction is completed, the solvent is removed by a rotary evaporator to obtain the macromolecular dispersant;

[0050] The polypropylene, high density polyethylene and linear low density polyethylene graft are added into a high-speed mixer, then the coupling agent, inorganic filler, macromolecular dispersant and antioxidant are added and mixed fully, and finally the alkali-free glass fiber is added and continuously mixed until uniform; the mixed material is melt blended by using a twin-screw extruder, and the temperature curve, shear rate and residence time are controlled, wherein the temperature curve is divided into four parts of feeding zone, plasticizing zone, homogenizing zone and outlet zone, the temperature of the feeding zone is controlled at 160℃, the temperature of the plasticizing zone is controlled at 190℃, the temperature of the homogenizing zone is controlled at 200℃, and the temperature of the outlet zone is controlled at 225℃, the shear rate is 600s -1 , and the residence time is 5min; finally, the composite material is extruded by an injection molding machine to obtain the high-rigidity and high-toughness seat PP composite material.

[0051] Embodiment 4: A high-rigidity and high-toughness seat PP composite material and a preparation method thereof, comprising the following steps:

[0052] Preparation of components: 30 parts by weight of polypropylene, 10 parts by weight of high-density polyethylene, 6 parts by weight of linear low-density polyethylene graft, 10 parts by weight of calcium carbonate, 5 parts by weight of alkali-free glass fiber, 0.3 parts by weight of γ-aminopropyl triethoxysilane, and 2 parts by weight of macromolecular dispersant

[0053] 2 parts by weight and 0.2 parts by weight of tris [2.4-di-tert-butyl phenyl] phosphite;

[0054] Wherein, the linear low-density polyethylene graft is prepared by mixing linear low-density polyethylene, 3-(vinyl oxy) prop-1-amine and mesitylic acid in a mass ratio of 10:0.5:3; the macromolecular dispersant is obtained by mixing maleic anhydride grafted polypropylene and 3-(urea amino) propyl triethoxysilane in a mass ratio of 1:1.7;

[0055] The content of dicumyl peroxide is 0.5% of the mass of linear low-density polyethylene; the molar ratio of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, 4-dimethylaminopyridine, triethylamine and erucic acid is 1:0.1:1:1;

[0056] The linear low-density polyethylene, 3-(vinyl oxy) prop-1-amine and dicumyl peroxide are put into a high-speed mixer and mixed uniformly at room temperature to ensure uniform distribution of each component. The mixed material is then added to an internal mixer, set to a temperature of 170℃ and a rotation speed of 50 rpm, and mixed for 15 min. After mixing, the product is immediately taken out and rapidly cooled to obtain the preliminary modified linear low-density polyethylene. The preliminary modified linear low-density polyethylene, erucic acid, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, 4-dimethylaminopyridine and triethylamine are again put into the internal mixer, set to a reaction temperature of 160℃ and a holding time of 2 h. After the reaction is completed, the product is immediately taken out and rapidly cooled, and then granulated to obtain the linear low-density polyethylene graft;

[0057] The maleic anhydride grafted polypropylene is dissolved in dichloromethane to prepare a 5% w / v solution, and 4-dimethylaminopyridine is added to obtain a mixed solution. The addition amount of dimethylaminopyridine is 1% of the mass of maleic anhydride grafted polypropylene. Under nitrogen protection, 3-(urea amino) propyl triethoxysilane is added dropwise to the mixed solution while stirring. The reaction mixture is heated to 80℃, and the reaction time is 4 h. After the reaction is completed, the solvent is removed by a rotary evaporator to obtain the macromolecular dispersant;

[0058] The polypropylene, high-density polyethylene and linear low-density polyethylene graft are added into a high-speed mixer, then a coupling agent, an inorganic filler, a macromolecular dispersing agent and an antioxidant are added and mixed well, finally, the non-alkali glass fiber is added and mixed until uniform, the mixed material is melt-blended by using a double screw extruder, a temperature curve is set, a shear rate and a residence time are controlled, wherein the temperature curve is divided into four parts of a feeding zone, a plasticizing zone, a homogenizing zone and an outlet zone, the temperature of the feeding zone is controlled at 160℃, the temperature of the plasticizing zone is controlled at 190℃, the temperature of the homogenizing zone is controlled at 200℃, the temperature of the outlet zone is controlled at 225℃, the shear rate is 600s -1 , the residence time is 5min, finally, the composite material is extruded by an injection molding machine to obtain the high-rigidity and high-toughness seat PP composite material.

[0059] Embodiment 5: A high-rigidity and high-toughness seat PP composite material and a preparation method thereof, comprising the following steps:

[0060] Preparation of components: 50 parts by weight of polypropylene, 25 parts by weight of high-density polyethylene, 3 parts by weight of linear low-density polyethylene graft, 20 parts by weight of calcium carbonate, 10 parts by weight of non-alkali glass fiber, 0.6 parts by weight of γ-aminopropyl triethoxysilane, 1 part by weight of macromolecular dispersing agent and 0.5 parts by weight of tris[2.4-di-tert-butylphenyl]phosphite;

[0061] The linear low-density polyethylene graft is prepared by mixing linear low-density polyethylene, 3-(vinyl oxy) prop-1-amine and mesitylic acid at a mass ratio of 10:0.5:3; the macromolecular dispersing agent is obtained by mixing maleic anhydride grafted polypropylene and 3-(urea amino) propyl triethoxysilane at a mass ratio of 1:1.7;

[0062] The dicumyl peroxide accounts for 2% of the mass of the linear low-density polyethylene; the molar ratio of the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, 4-dimethylaminopyridine, triethylamine and erucic acid is 1.5:0.5:1:1;

[0063] The linear low-density polyethylene, 3-(vinyl oxy) prop-1-amine and dicumyl peroxide are put into a high-speed mixer and mixed uniformly at room temperature to ensure uniform distribution of each component, the mixed material is added into an internal mixer, the temperature is set at 170℃, the rotating speed is 50rpm, and the mixing time is 15min, after the mixing is completed, the product is immediately taken out and rapidly cooled to obtain the preliminary modified linear low-density polyethylene; the preliminary modified linear low-density polyethylene, erucic acid, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, 4-dimethylaminopyridine and triethylamine are again put into the internal mixer, the reaction temperature is set at 160℃, and the holding time is 2h, after the reaction is completed, the product is immediately taken out and rapidly cooled, and then the product is made into a pellet to obtain the linear low-density polyethylene graft.

[0064] The maleic anhydride grafted polypropylene is dissolved in dichloromethane to prepare a 5% w / v solution, 4-dimethylaminopyridine is added to obtain a mixed solution, wherein the addition amount of dimethylaminopyridine is 1% of the mass of the maleic anhydride grafted polypropylene, 3-(urea amino) propyl triethoxysilane is added dropwise into the mixed solution under the protection of nitrogen, while stirring, the reaction mixture is heated to 80℃, the reaction time is 4h, after the reaction is completed, the solvent is removed by a rotary evaporator to obtain a macromolecular dispersant;

[0065] The polypropylene, high-density polyethylene and linear low-density polyethylene graft are added into a high-speed mixer, then the coupling agent, inorganic filler, macromolecular dispersant and antioxidant are added and mixed fully, finally the alkali-free glass fiber is added and continues to be mixed until uniform, the mixed material is melt blended by using a twin-screw extruder, the temperature curve is set, the shear rate and the residence time are controlled, wherein the temperature curve is divided into four parts of feeding zone, plasticizing zone, homogenizing zone and outlet zone, the temperature of the feeding zone is controlled at 160℃, the temperature of the plasticizing zone is controlled at 190℃, the temperature of the homogenizing zone is controlled at 200℃, the temperature of the outlet zone is controlled at 225℃, the shear rate is 600s -1 , the residence time is 5min, finally the composite material is extruded by an injection molding machine to obtain a high-rigidity and high-toughness seat PP composite material.

[0066] Embodiment 6: A high-rigidity and high-toughness seat PP composite material and a preparation method thereof, comprising the following steps:

[0067] Preparation of components: 50 parts by weight of polypropylene, 25 parts by weight of high-density polyethylene, 5 parts by weight of linear low-density polyethylene graft, 20 parts by weight of calcium carbonate, 10 parts by weight of alkali-free glass fiber, 0.6 parts by weight of γ-aminopropyl triethoxysilane, 1.5 parts by weight of macromolecular dispersant and 0.5 parts by weight of tris[2.4-di-tert-butylphenyl] phosphite;

[0068] Wherein, the linear low-density polyethylene graft is prepared by mixing linear low-density polyethylene, 3-(vinyl oxy) prop-1-amine and mesitylic acid according to a mass ratio of 10:0.5:3; the macromolecular dispersant is obtained by mixing maleic anhydride grafted polypropylene and 3-(urea amino) propyl triethoxysilane according to a mass ratio of 1:1.7;

[0069] The dicumyl peroxide accounts for 2% of the mass of the linear low-density polyethylene; the molar ratio of the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, 4-dimethylaminopyridine, triethylamine and erucic acid is 1.5:0.5:1:1;

[0070] The linear low density polyethylene, 3-(vinyl oxy) propyl-1-amine and dicumyl peroxide were put into a high-speed mixer, mixed uniformly at room temperature to ensure uniform distribution of the components, and then the mixed material was added into an internal mixer, set at a temperature of 170℃ and a rotation speed of 50 rpm, and mixed for 15 min. After the mixing was completed, the product was immediately taken out and rapidly cooled to obtain the preliminary modified linear low density polyethylene. The preliminary modified linear low density polyethylene, erucic acid, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, 4-dimethylaminopyridine and triethylamine were again put into the internal mixer, set at a reaction temperature of 160℃ and a holding time of 2 h, and after the reaction was completed, the product was immediately taken out and rapidly cooled, and then the product was made into a pellet to obtain the linear low density polyethylene grafting product.

[0071] The maleic anhydride grafted polypropylene was dissolved in dichloromethane to prepare a 5% w / v solution, and 4-dimethylaminopyridine was added to obtain a mixed solution, wherein the addition amount of dimethylaminopyridine was 1% of the mass of the maleic anhydride grafted polypropylene. Under the protection of nitrogen, 3-(urea amino) propyl triethoxysilane was added dropwise into the mixed solution while stirring, and the reaction mixture was heated to 80℃. The reaction time was 4 h. After the reaction was completed, the solvent was removed by a rotary evaporator to obtain a macromolecular dispersant.

[0072] The polypropylene, high density polyethylene and linear low density polyethylene grafting product were added into a high-speed mixer, and then the coupling agent, inorganic filler, macromolecular dispersant and antioxidant were added and mixed thoroughly. Finally, the alkali-free glass fiber was added and continuously mixed until uniform. The mixed material was melt blended by using a twin-screw extruder, and a temperature curve was set to control the shear rate and residence time. The temperature curve was divided into four parts, i.e. a feeding zone, a plasticizing zone, a homogenizing zone and an outlet zone. The temperature of the feeding zone was controlled at 160℃, the temperature of the plasticizing zone was controlled at 190℃, the temperature of the homogenizing zone was controlled at 200℃, and the temperature of the outlet zone was controlled at 225℃. The shear rate was 600 s -1 , and the residence time was 5 min. Finally, the composite material was extruded by an injection molding machine to obtain a high-rigidity and high-toughness seat PP composite material.

[0073] Comparative Example 1: The method of Example 3 was used, and the linear low density polyethylene grafting product was not added.

[0074] Comparative Example 2: The method of Example 3 was used, and the linear low density polyethylene was directly used without modification of the linear low density polyethylene by 3-(vinyl oxy) propyl-1-amine and erucic acid.

[0075] Comparative Example 3: The method of Example 3 was used, and 3-(vinyl oxy) propyl-1-amine and the linear low density polyethylene were directly used without modification of the 3-(vinyl oxy) propyl-1-amine and the linear low density polyethylene by erucic acid.

[0076] Comparative Example 4: The method of Example 3 was used, directly using maleic anhydride grafted polypropylene, without modification of the maleic anhydride grafted polypropylene by 3-(urea amino) propyl triethoxysilane.

[0077] The high-rigidity high-toughness seat PP composite material prepared by using the linear low-density polyethylene grafting material has the following performance index test items and test standards:

[0078] The tensile strength and elongation at break of the seat polypropylene composite material were tested according to GB / T 1040.1-2018 “Determination of tensile properties of plastics”, the tensile strength refers to the maximum stress that the material can withstand before breaking, and the elongation at break reflects the percentage change in relative length of the material at the time of breaking, and the two parameters comprehensively evaluate the tensile resistance and elastic recovery capacity of the material; the bending strength, bending modulus and cantilever beam notched impact strength of the seat polypropylene composite material were tested according to GB / T 9341-2008 “Determination of bending properties of plastics”, the bending strength refers to the maximum stress that the material can withstand under three-point bending or four-point bending conditions, the bending modulus reflects the ability of the material to resist bending deformation, and the cantilever beam notched impact strength evaluates the ability of the material to resist sudden impact load; the melt index of the seat polypropylene composite material was tested according to GB / T 3682-2000 “Determination of melt mass flow rate and melt volume flow rate of thermoplastics”, the melt index is the mass of thermoplastic flowing out from a specified diameter and length orifice within a certain time under specific temperature and pressure, and is used to characterize the flowability of the plastic.

[0079] After fixing the seat, the backrest was stretched with a tensile tester, and the tensile value used under the same displacement deformation was tested, the greater the tensile value, the stronger the rigidity of the product, the tensile values under displacement of 5 cm and 10 cm at room temperature 25℃ were tested respectively, the tensile values under displacement of 5 cm and 10 cm were tested within 5 minutes after taking out from the constant temperature bath at high temperature 40℃ for 1 hour, and the tensile values under displacement of 5 cm and 10 cm were tested within 5 minutes after taking out from the constant temperature bath at high temperature 80℃ for 1 hour.

[0080] After fixing the seat, the backrest was stretched with a tensile tester, and the displacement amount of the seat under the same tensile force of 200N was tested, the smaller the displacement amount, the smaller the deformability and the better the resilience of the product, so as to determine the resilience and deformability of the seat.

[0081] The high-rigidity high-toughness seat PP composite material prepared by using the linear low-density polyethylene grafting material has the following performance index test items and test standards:

[0082] Table 1 Performance data of Examples 1-6 and Comparative Examples 1-4

[0083]

[0084] Table 2 Performance data of Examples 1-6 and Comparative Examples 1-4

[0085]

[0086] Table 3 Performance data of Examples 1-6 and Comparative Examples 1-4

[0087]

[0088] The above data fully shows that Examples 1-6 compared to Comparative Examples 1-4, the role of linear low density polyethylene graft on the stiffness and toughness performance of seat polypropylene composite material can be fully seen.

[0089] Since the present application uses linear low density polyethylene graft to prepare high stiffness and toughness seat PP composite material, the performance of high stiffness and toughness seat PP composite material is effectively improved by linear low density polyethylene graft, which is as follows:

[0090] As can be seen from Examples 1-3, with the continuous increase of the proportion of linear low density polyethylene graft and macromolecular dispersant component, the stiffness and toughness of seat polypropylene composite material are significantly improved, which shows that 3-(vinyl oxy) propyl-1-amine provides amino group, enhances the polarity of linear low density polyethylene, and mesaconic acid promotes the formation of hydrogen bond or chemical bond between linear low density polyethylene and inorganic filler and non-alkali glass fiber surface through long chain branch structure, thereby improving the compatibility and interface bonding force, and increasing the intermolecular interaction, increasing the cohesion of the material, so that the composite material is not easy to break when subjected to external force, improving its toughness and elongation at break. At the same time, by adding macromolecular dispersant, the active groups on maleic anhydride and 3-(urea amino) propyl triethoxysilane interact with inorganic filler and non-alkali glass fiber, the micro defects are reduced through good interface compatibility, the stress distribution in the material is more uniform, and the composite material has higher stiffness and toughness.

[0091] As can be seen from Example 2 and Example 4, with the continuous change of the content of other components, the stiffness and toughness of seat polypropylene composite material have no obvious change, which shows that the small change of other components within a certain range is not enough to significantly affect the stiffness and toughness of seat polypropylene composite material.

[0092] As can be seen from Example 2, Example 5 and Example 6, with the change of the content of linear low density polyethylene graft and macromolecular dispersant, the stiffness and toughness of the seat polypropylene composite material are constantly changing, more linear low density polyethylene graft means that there are more active functional groups in the composite material that can participate in the interaction of inorganic fillers and alkali-free glass fibers, thereby more effectively promoting dispersion and coupling, the reinforcing effect of alkali-free glass fibers and inorganic fillers is fully played, and a high content of macromolecular dispersant helps to more uniformly disperse the fillers, reduces the agglomeration phenomenon, optimizes the microstructure of the composite material, and improves the mechanical properties.

[0093] According to the above test experiments, the seat PP composite material with high stiffness and high toughness prepared according to Example 3 has the optimal performance, and Example 3 is taken as the optimal example.

[0094] As can be seen from the comparison of Example 3 and Comparative Examples 1-4, the following can be seen:

[0095] Comparative Example 1 does not add linear low density polyethylene graft, and the stiffness and toughness of the seat polypropylene composite material are worse, because the introduction of the graft is not introduced, the interface force between the polypropylene matrix and the inorganic filler is weak, the filler agglomeration phenomenon is serious, the stress concentration in the material is caused, and the mechanical properties are reduced, so the 3-(vinyl oxy) propyl-1-amine and erucic acid graft of linear low density polyethylene is crucial in enhancing the interface compatibility and dispersion uniformity.

[0096] Comparative Example 2 directly uses linear low density polyethylene, without modification of linear low density polyethylene by 3-(vinyl oxy) propyl-1-amine and erucic acid, and the stiffness and toughness of the seat polypropylene composite material are poor, because the unmodified linear low density polyethylene lacks polar groups, the interface bonding force between the inorganic filler and the glass fiber is weak, the filler is not uniformly dispersed, and the overall performance of the material is affected.

[0097] Comparative Example 3 directly uses 3-(vinyl oxy) propyl-1-amine and linear low density polyethylene, without modification of 3-(vinyl oxy) propyl-1-amine and linear low density polyethylene by erucic acid, and the stiffness and toughness of the seat polypropylene composite material are poor, because the segment of 3-(vinyl oxy) propyl-1-amine is short, lacks the branched chain extension effect of erucic acid, the intermolecular entanglement and coating effect is insufficient, and then the interface bonding force and impact toughness is reduced, so the stiffness and toughness of the seat polypropylene composite material is reduced.

[0098] The comparative example 4 directly uses the maleic anhydride grafted polypropylene without modification by 3-(urea amino) propyl triethoxysilane, and the stiffness and toughness of the seat polypropylene composite material is poor. The unmodified maleic anhydride grafted polypropylene only provides carboxyl force, and although it can provide certain interface bonding force, its functional group is single, while the functional group of the maleic anhydride grafted polypropylene modified by 3-(urea amino) propyl triethoxysilane is diversified. Therefore, the affinity of the unmodified maleic anhydride grafted polypropylene to the inorganic filler is relatively poor, thereby causing the stiffness and toughness of the seat polypropylene composite material to decrease.

[0099] In summary, through the interaction of the linear low density polyethylene graft, the macromolecular dispersant, the inorganic filler and the non-alkali glass fiber, the compatibility of the seat polypropylene composite material can be improved by the polar group of 3-(vinyl oxy) prop-1-amine and the long branch of mesitylic acid, the affinity to the inorganic filler and the non-alkali glass fiber can be improved by the carboxyl of the maleic anhydride grafted polypropylene and the siloxane of 3-(urea amino) propyl triethoxysilane through the multi-active functional groups, thereby improving the mechanical properties of the seat polypropylene composite material, and the seat polypropylene composite material has excellent stiffness, good resilience and non-deformation.

[0100] The above shows and describes the basic principles, main features and advantages of the present application. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only preferred examples of the present application, and are not intended to limit the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the present application.

Claims

1. A high stiffness high toughness seat PP composite, characterized in that, The composition comprises the following components: polypropylene 30-50 parts by weight, high density polyethylene 10-25 parts by weight, linear low density polyethylene grafting 3-6 parts by weight, inorganic filler 10-20 parts by weight, alkali-free glass fiber 5-10 parts by weight, coupling agent 0.3-0.6 parts by weight, macromolecular dispersant 1-2 parts by weight and antioxidant 0.2-0.5 parts by weight; The linear low density polyethylene grafting is prepared by mixing linear low density polyethylene, 3-(vinyl oxy) propyl-1-amine and mesitylic acid according to a mass ratio of 10:0.1-0.5:2-3. The preparation method of the linear low density polyethylene grafting is as follows: The linear low density polyethylene, 3-(vinyl oxy) propyl-1-amine and dicumyl peroxide are put into a high-speed mixer, mixed uniformly at room temperature, and the components are uniformly distributed, the mixed material is added into an internal mixer, the temperature is set to 160-190℃, the rotating speed is 40-50rpm, the mixing time is 15-20min, after mixing, the product is immediately taken out and rapidly cooled to obtain the linear low density polyethylene modified preliminarily; the linear low density polyethylene modified preliminarily, erucic acid, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, 4-dimethylaminopyridine and triethylamine are put into the internal mixer again, the reaction temperature is set to 150-170℃, the holding time is 1-2h, after the reaction is completed, the product is immediately taken out and rapidly cooled, and then the product is made into a granule to obtain the linear low density polyethylene grafting. The macromolecular dispersant is prepared by mixing maleic anhydride grafted polypropylene and 3-(urea amino) propyl triethoxysilane according to a mass ratio of 1:1.5-1.

7. The preparation method of the macromolecular dispersant is as follows: The maleic anhydride grafted polypropylene is dissolved in dichloromethane to prepare a 3-8%w / v solution, 4-dimethylaminopyridine is added to obtain a mixed solution, wherein the addition amount of dimethylaminopyridine is 0.1-5% of the mass of the maleic anhydride grafted polypropylene, 3-(urea amino) propyl triethoxysilane is added dropwise into the mixed solution under nitrogen protection while stirring, the reaction mixture is heated to 60-80℃, the reaction time is 4-6h, after the reaction is completed, the solvent is removed by a rotary evaporator to obtain the macromolecular dispersant.

2. The high stiffness high toughness seat PP composite of claim 1, wherein: The inorganic filler is one or more combinations of calcium carbonate, talc powder, mica powder, wollastonite, kaolin, magnesium hydroxide and aluminum hydroxide.

3. The high stiffness high toughness seat PP composite of claim 1, wherein: The coupling agent is one or more combinations of γ-aminopropyl triethoxysilane, vinyl trimethoxysilane and bis(dioctyl pyrophosphato) titanium diisopropylate.

4. The high stiffness high toughness seat PP composite of claim 1, wherein: The antioxidant is one or more combinations of 3,5-di-tert-butyl-4-hydroxyphenyl propyl n-octadecyl ester, tris[2.4-di-tert-butylphenyl] phosphite and didodecyl thiodipropionate.

5. The high stiffness high toughness seat PP composite of claim 1, wherein: The dicumyl peroxide accounts for 0.5-2% of the mass of the linear low density polyethylene; the molar ratio of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, 4-dimethylaminopyridine, triethylamine and erucic acid is 1-1.5:0.1-0.5:1:

1.

6. A method for producing a high-rigidity high-toughness seat PP composite material for producing the high-rigidity high-toughness seat PP composite material according to any one of claims 1 to 5, characterized by, The method comprises the following steps: Polypropylene, high density polyethylene and linear low density polyethylene grafts are added to a high-speed mixer, then a coupling agent, inorganic filler, macromolecular dispersant and antioxidant are added and mixed well, finally, non-alkali glass fiber is added and mixed until uniform, the mixed material is melt blended using a twin-screw extruder, a temperature curve is set, the shear rate and residence time are controlled, finally, the composite material is extruded through an injection molding machine to obtain a high stiffness and high toughness seat PP composite material.

7. The method of making a high stiffness high tenacity seat PP composite of claim 6, wherein: The temperature curve is divided into four parts of feeding zone, plasticizing zone, homogenizing zone and outlet zone, the temperature of the feeding zone is controlled at 160-180 DEG C, the temperature of the plasticizing zone is controlled at 190-210 DEG C, the temperature of the homogenizing zone is controlled at 200-220 DEG C, and the temperature of the outlet zone is controlled at 205-225 DEG C.

8. The method of making a high stiffness high tenacity seat PP composite of claim 7, wherein: The shear rate 300-600 s -1 , residence time 1-5 min.

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