Impact-resistant high-transparency polypropylene material and preparation method thereof

Abstract

The invention discloses an impact-resistant high-transparency polypropylene material and a preparation method thereof, belongs to the technical field of high polymer materials, and solves the problem that transparency and impact resistance of a polypropylene material need to be further improved. The preparation method of the impact-resistant high-transparency polypropylene material comprises the following steps: in an inert gas environment, heating polypropylene, adding nano-montmorillonite grafted modified nano-silica and an initiator, stirring, heating and preserving heat to obtain modified polypropylene; polypropylene, modified polypropylene, maleic anhydride grafted polypropylene, an ethylene-octylene copolymer elastomer, an antioxidant and a lubricant are subjected to melt blending, extrusion and cooling, and the impact-resistant high-transparency polypropylene material is obtained. The impact-resistant high-transparency polypropylene material obtained by the invention meets good impact resistance and high transparency, also has good high temperature resistance and flame retardant property, and is beneficial to widening the application range.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, in particular to an impact-resistant and highly transparent polypropylene material and a preparation method thereof. Background Art

[0002] In recent years, the plastics industry has developed rapidly, and plastic products have been deeply integrated into all areas of the national economy, with extremely diverse application scenarios. Polypropylene, as a typical representative of general-purpose polymer materials, has been widely used in industry and life due to its low density, excellent electrical insulation, stable chemical properties and low cost. However, it cannot be ignored that its lack of transparency has limited its application. People can effectively improve the toughness and crystallization properties of polypropylene by adding nucleating agents during the production process. Sorbitol nucleating agents release toxic formaldehyde gas during the nucleation process and have poor high temperature resistance. Adding elastomers to polypropylene can improve impact resistance. As the elastomer content increases, the impact resistance will show a certain increasing trend, but the haze will increase instead, which is not conducive to transparency. Simply adding elastomers cannot balance the impact resistance and transparency of polypropylene materials.

[0003] Chinese patent CN105566770B discloses an impact-resistant, highly transparent polypropylene composition and a preparation method thereof. The impact-resistant, highly transparent polypropylene composition is prepared by mixing a polypropylene resin, a polyolefin elastomer, a metallocene linear low-density polyethylene, a weathering additive, and a colorant in a mass ratio of 100:(6-15):(12-38):(0.06-0.46):(0.002-0.015). The impact-resistant, highly transparent polypropylene composition prepared by this invention has transparency and high impact resistance. However, the minimum haze in this invention is 9.1%, which needs to be further improved. Chinese patent CN112375304B discloses a transparent polypropylene material and a preparation method thereof. The transparent polypropylene material comprises a mixture of polypropylene resin powder, a primary antioxidant, an auxiliary antioxidant, a halogen absorber, and a nucleating agent in a mass ratio of (99.48-99.56):(0.1-0.12):(0.08-0.1):(0.06-0.1):(0.2-0.25). The impact strength of this invention needs to be strengthened, and the haze is high, which limits its application. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an impact-resistant and highly transparent polypropylene material and a preparation method thereof, thereby solving the problem that the transparency and impact resistance of polypropylene materials need to be further improved. The impact-resistant and highly transparent polypropylene material prepared by the present invention satisfies the requirements of good impact resistance and high transparency, and also has good high temperature resistance and flame retardancy, which is conducive to expanding the scope of application.

[0005] In order to achieve the above object, the present invention provides a method for preparing an impact-resistant and highly transparent polypropylene material, comprising the following steps: Step (1) HTSO, 1,2-epoxy-9-decene and anhydrous ethanol are mixed, stirred, heated, chloroplatinic acid is added, reacted, and after the reaction is completed, vacuum distillation is performed to obtain modified HTSO; Step (2) mixing the modified HTSO, amino-modified nano-silica and anhydrous ethanol, stirring, adding a hydrochloric acid aqueous solution, heating for reaction, completing the reaction, filtering, washing, and drying to obtain HTSO-grafted nano-silica; Step (3) mixing allyl succinic anhydride, HTSO-grafted nano-silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide, heating to react, filtering, washing and drying after the reaction is completed to obtain modified nano-silica; Step (4) tetrahydrofuran, deionized water, modified nano-silica and amino-modified nano-montmorillonite are mixed, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride is added, and the mixture is heated for reaction. After the reaction is completed, the mixture is filtered, washed and dried to obtain nano-montmorillonite grafted modified nano-silica; Step (5) in an inert gas environment, heating the polypropylene, adding the nano-montmorillonite grafted modified nano-silica and an initiator, stirring, heating and keeping warm, cooling, extracting, and drying to obtain modified polypropylene; Step (6) melt-blending the polypropylene, modified polypropylene, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant and lubricant, extruding and cooling to obtain an impact-resistant and highly transparent polypropylene material.

[0006] Preferably, the preparation method of amino-modified nano-silica comprises the following steps: Nano-silica, anhydrous ethanol, and γ-aminoethylaminopropyltrimethoxysilane are uniformly mixed, heated, reacted, centrifuged, washed, and dried to obtain amino-modified nano-silica; Wherein, the mass ratio of nano-silica, anhydrous ethanol and γ-aminoethylaminopropyltrimethoxysilane is (20-40):(1000-2000):(6-8); The reaction temperature is 60-80°C and the reaction time is 4-6h.

[0007] Preferably, the preparation method of amino-modified nano-montmorillonite comprises the following steps: Adding γ-aminopropyltriethoxysilane to deionized water, stirring and heating, adding nano-montmorillonite, stirring and reacting, cooling, centrifuging, washing with deionized water, and drying to obtain amino-modified nano-montmorillonite; Wherein, the mass ratio of γ-aminopropyltriethoxysilane, deionized water and nano-montmorillonite is (2-4):(150-240):(20-40); The reaction temperature is 85-95°C and the reaction time is 3-4h; Among them, the stirring speed is 20-40r / min.

[0008] Preferably, in step (1), the mass ratio of HTSO, 1,2-epoxy-9-decene, anhydrous ethanol and chloroplatinic acid is (8-10):(40-80):(100-220):(0.1-0.5); the reaction temperature is 80-100°C, and the reaction time is 4-6h.

[0009] Preferably, in step (2), the mass ratio of modified HTSO, amino-modified nano-silica, anhydrous ethanol and hydrochloric acid aqueous solution is (10-14):(80-100):(300-500):(10-18), the reaction temperature is 55-75°C, and the reaction time is 5-7h.

[0010] Preferably, the concentration of the hydrochloric acid aqueous solution is 0.01 mol / L.

[0011] Preferably, in step (3), the mass ratio of allylsuccinic anhydride, HTSO-grafted nano-silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide is (30-50):(80-180):(350-750):(3-5):(1-2); the reaction temperature is 80-90°C, and the reaction time is 3-7h.

[0012] Preferably, in step (4), the mass ratio of tetrahydrofuran, deionized water, modified nano-silica, amino-modified nano-montmorillonite and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride is (2000-3200):(800-1400):(35-55):(80-100):(50-90); the reaction temperature is 55-65°C, and the reaction time is 7-11 hours.

[0013] Preferably, in step (5), the mass ratio of polypropylene, nano-montmorillonite grafted modified nano-silica and initiator is (90-100):(5-15):(0.5-1.3); the reaction temperature is 85-95°C, and the reaction time is 0.5-1.5h.

[0014] Preferably, in step (5), the initiator is BPO.

[0015] Preferably, in step (6), the mass ratio of polypropylene, modified polypropylene, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant and lubricant is (70-80):(6-10):(2-6):(10-12):(0.1-0.3):(0.15-0.35).

[0016] Preferably, the lubricant is calcium stearate.

[0017] Preferably, in step (6), the antioxidant includes antioxidant 168 and antioxidant 1010; the mass ratio of antioxidant 168 to antioxidant 1010 is 1:1.

[0018] Preferably, melt blending is carried out in a twin-screw extruder, which is provided with five temperature zones according to the direction of material advancement, the temperatures of the temperature zones are 100-115°C, 120-135°C, 140-155°C, 160-175°C, and 180-195°C, respectively, and the speed of the twin-screw extruder is 140-180r / min.

[0019] The invention discloses an impact-resistant and highly transparent polypropylene material, which is prepared by the preparation method of the impact-resistant and highly transparent polypropylene material.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1. The nano-silica added in the present invention is an inorganic material and has a certain heat resistance. Appropriate addition will improve the thermal stability of the matrix. The amino-modified nano-silica obtained by modification with γ-aminoethylaminopropyltrimethoxysilane effectively avoids agglomeration, can be evenly dispersed, and maintains its functional stability. The silicon-oxygen bond energy in γ-aminoethylaminopropyltrimethoxysilane is large, which can effectively improve thermal stability. HTSO is an organic silane, which reacts with 1,2-epoxy-9-decene under Pt catalysis to obtain modified HTSO; the epoxy group in the modified HTSO undergoes a ring-opening reaction with the amino group in the amino-modified nano-silica to obtain HTSO-grafted nano-silica; the hydroxyl group in the HTSO-grafted nano-silica reacts with the anhydride in allylsuccinic anhydride to obtain modified nano-silica; at this time, the modified nano-silica is not only compatible with polypropylene, but also can utilize its inorganic skeleton to improve thermal stability and carbonization efficiency. At the same time, the modified nano-silica has excellent compatibility and dispersibility with polypropylene. Since nano-silica can be used as an inorganic nucleating agent, the better the dispersibility, the better the ability to suppress haze.

[0021] 2. The nano-montmorillonite added in this invention acts as a nucleating agent, effectively refining crystal particles, reducing light scattering, and improving transparency. As an inorganic particle, the appropriate amount can enhance the mechanical properties of the polypropylene matrix material. Furthermore, the nano-montmorillonite forms a layered char layer during combustion, which blocks oxygen and heat transfer. Its lamellar structure also adsorbs free radicals generated by combustion, inhibiting the gas-phase combustion chain reaction and providing a flame retardant effect. The nano-montmorillonite is modified with γ-aminopropyltriethoxysilane to produce amino-modified nano-montmorillonite. The amino groups in the amino-modified nano-montmorillonite react with the carboxyl groups in the modified nano-silica to produce nano-montmorillonite-grafted nano-silica. The nano-silica and montmorillonite synergistically form a composite layer, increasing the residual char rate and providing enhanced stability at high temperatures. The nitrogen introduced in this invention also generates non-combustible gases during combustion, diluting the oxygen concentration in the combustion system and providing a flame retardant effect.

[0022] 3. In the method for preparing the impact-resistant, highly transparent polypropylene material provided by the present invention, the unsaturated double bonds of nano-silica grafted with nano-montmorillonite react with polypropylene under the action of an initiator to produce modified polypropylene. The modified polypropylene exhibits good compatibility with polypropylene and facilitates the dispersion of the functional particles, thereby enhancing overall mechanical properties. Ethylene-octene copolymer elastomer (POE) serves as a flexible phase, improving the impact resistance of the matrix material by inducing silver crazing / shear banding to absorb impact energy. It also reduces the crystallinity of the polypropylene material, thereby reducing haze. Maleic anhydride, a compatibilizer, is grafted onto the polypropylene to improve interfacial adhesion between the matrix and POE, effectively preventing crack propagation and enhancing interfacial stress transfer, thereby improving impact resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a process flow chart for preparing the impact-resistant and highly transparent polypropylene material of the present invention; Figure 2 Schematic diagram of the reaction for preparing modified HTSO in the present invention; Figure 3 Schematic diagram of the reaction for preparing HTSO-grafted nano-silica in the present invention; Figure 4 This is a bar graph showing the results of simply supported beam notched impact strength tests of Examples 1-5 and Comparative Examples 1-3 of the present invention; Figure 5 This is a bar chart showing the haze test results of Examples 1-5 and Comparative Examples 1-3 of the present invention. DETAILED DESCRIPTION

[0024] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] Example 1 This embodiment provides a method for preparing an impact-resistant and highly transparent polypropylene material, comprising the following steps: Step (1) HTSO, 1,2-epoxy-9-decene, anhydrous ethanol and chloroplatinic acid were mixed in a mass ratio of 8:40:100:0.1, reacted at 80°C for 6 hours, and after the reaction was completed, vacuum distillation was performed at 0.08 MPa and 60°C for 4 hours to obtain modified HTSO; Step (2) modified HTSO, amino-modified nano-silica, anhydrous ethanol and 0.01 mol / L hydrochloric acid aqueous solution were mixed in a mass ratio of 10:80:300:10, stirred, and reacted at 55°C for 7 hours. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried at 80°C for 8 hours to obtain HTSO-grafted nano-silica; Step (3) allyl succinic anhydride, HTSO-grafted nano-silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide were mixed in a mass ratio of 30:80:350:3:1, reacted at 80°C for 7 hours, filtered, washed with deionized water, and dried at 90°C for 7 hours to obtain modified nano-silica; Step (4) tetrahydrofuran, deionized water, modified nano-silica, amino-modified nano-montmorillonite and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride were mixed in a mass ratio of 2000:800:35:80:50, reacted at 55°C for 11 hours, filtered, washed with deionized water, and dried at 70°C for 5 hours to obtain nano-montmorillonite grafted modified nano-silica; Step (5) In an Ar gas environment, the polypropylene is heated to 60°C and kept warm for 2.5 hours, the nano-montmorillonite grafted modified nano-silica and the initiator BPO are added, the mixture is stirred at a speed of 120 r / min for 10 minutes, the mixture is heated to 85°C and kept warm for 1.5 hours, the mixture is cooled to room temperature, extracted with acetone for 24 hours, and dried at a vacuum degree of 0.05 MPa and a temperature of 60°C for 24 hours to obtain modified polypropylene; The mass ratio of polypropylene, nano-montmorillonite grafted modified nano-silica and initiator BPO is 90:5:0.5; Step (6) melt-blending polypropylene, modified polypropylene, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant and calcium stearate in a twin-screw extruder in a mass ratio of 70:6:2:10:0.1:0.15, setting five temperature zones according to the forward direction of the materials, the temperatures of the temperature zones are 100° C., 120° C., 140° C., 160° C. and 180° C., respectively, and the speed of the twin-screw extruder is 180 r / min. After the blending is completed, the mixture is cooled to obtain an impact-resistant and highly transparent polypropylene material; The mass ratio of antioxidant 168 to antioxidant 1010 in the antioxidant is 1:1.

[0026] Example 2 This embodiment provides a method for preparing an impact-resistant and highly transparent polypropylene material, comprising the following steps: Step (1) HTSO, 1,2-epoxy-9-decene, anhydrous ethanol and chloroplatinic acid were mixed in a mass ratio of 8.5:50:130:0.2, reacted at 85°C for 5.5 hours, and after the reaction was completed, vacuum distilled at 0.08 MPa and 62°C for 3.8 hours to obtain modified HTSO; Step (2) modified HTSO, amino-modified nano-silica, anhydrous ethanol and 0.01 mol / L hydrochloric acid aqueous solution were mixed in a mass ratio of 11:85:350:12, stirred, and reacted at 60°C for 6.5 hours. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried at 85°C for 7.5 hours to obtain HTSO-grafted nano-silica; Step (3) allyl succinic anhydride, HTSO-grafted nano-silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide were mixed in a mass ratio of 35:105:450:3.5:1.2, reacted at 82°C for 6 hours, filtered, washed with deionized water, and dried at 92°C for 6.5 hours to obtain modified nano-silica; Step (4) tetrahydrofuran, deionized water, modified nano-silica, amino-modified nano-montmorillonite and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride were mixed in a mass ratio of 2300:950:40:85:60, reacted at 57°C for 10 hours, filtered, washed with deionized water, and dried at 75°C for 4.5 hours to obtain nano-montmorillonite grafted modified nano-silica; Step (5) In an Ar gas environment, the polypropylene is heated to 62°C and kept warm for 2.2 hours, the nano-montmorillonite grafted modified nano-silica and the initiator BPO are added, the mixture is stirred at a speed of 135 r / min for 9.5 minutes, the mixture is heated to 87°C and kept warm for 1.3 hours, the mixture is cooled to room temperature, extracted with acetone for 24 hours, and dried at a vacuum degree of 0.05 MPa and a temperature of 65°C for 22.5 hours to obtain modified polypropylene; Among them, the mass ratio of polypropylene, nano-montmorillonite grafted modified nano-silica and initiator BPO is 92:7.5:0.7; Step (6) melt-blending polypropylene, modified polypropylene, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant and calcium stearate in a twin-screw extruder in a mass ratio of 72:7:3:10.5:0.15:0.2, setting five temperature zones according to the forward direction of the materials, the temperatures of the temperature zones are 103°C, 123°C, 143°C, 163°C and 183°C, respectively, and the speed of the twin-screw extruder is 170 r / min. After the blending is completed, the mixture is cooled to obtain an impact-resistant and highly transparent polypropylene material; The mass ratio of antioxidant 168 to antioxidant 1010 in the antioxidant is 1:1.

[0027] Example 3 This embodiment provides a method for preparing an impact-resistant and highly transparent polypropylene material, comprising the following steps: Step (1) HTSO, 1,2-epoxy-9-decene, anhydrous ethanol and chloroplatinic acid were mixed in a mass ratio of 9:60:160:0.3, reacted at 90°C for 5 hours, and after the reaction was completed, vacuum distillation was performed at 0.08 MPa and 65°C for 3.5 hours to obtain modified HTSO; Step (2) modified HTSO, amino-modified nano-silica, anhydrous ethanol and 0.01 mol / L hydrochloric acid aqueous solution were mixed in a mass ratio of 12:90:400:14, stirred, and reacted at 65°C for 6 hours. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried at 90°C for 7 hours to obtain HTSO-grafted nano-silica; Step (3) allyl succinic anhydride, HTSO-grafted nano-silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide were mixed in a mass ratio of 40:130:550:4:1.5, reacted at 85°C for 5 hours, filtered, washed with deionized water, and dried at 95°C for 6 hours to obtain modified nano-silica; Step (4) tetrahydrofuran, deionized water, modified nano-silica, amino-modified nano-montmorillonite and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride were mixed in a mass ratio of 2600:1100:45:90:70, reacted at 60°C for 9 hours, filtered, washed with deionized water, and dried at 80°C for 4 hours to obtain nano-montmorillonite grafted modified nano-silica; Step (5) In an Ar gas environment, the polypropylene is heated to 65°C and kept warm for 2 hours, the nano-montmorillonite grafted modified nano-silica and the initiator BPO are added, the mixture is stirred at a speed of 150 r / min for 9 minutes, the mixture is heated to 90°C and kept warm for 1 hour, the mixture is cooled to room temperature, extracted with acetone for 24 hours, and dried at a vacuum degree of 0.05 MPa and a temperature of 70°C for 21 hours to obtain modified polypropylene; The mass ratio of polypropylene, nano-montmorillonite grafted modified nano-silica and initiator BPO is 95:10:0.9; Step (6) melt-blending polypropylene, modified polypropylene, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant and calcium stearate in a twin-screw extruder in a mass ratio of 75:8:4:11:0.2:0.25, setting five temperature zones according to the forward direction of the materials, the temperatures in the temperature zones are 107°C, 127°C, 147°C, 167°C and 187°C, respectively, and the speed of the twin-screw extruder is 160 r / min. After the blending is completed, the mixture is cooled to obtain an impact-resistant and highly transparent polypropylene material; The mass ratio of antioxidant 168 to antioxidant 1010 in the antioxidant is 1:1.

[0028] Example 4 This embodiment provides a method for preparing an impact-resistant and highly transparent polypropylene material, comprising the following steps: Step (1) HTSO, 1,2-epoxy-9-decene, anhydrous ethanol and chloroplatinic acid were mixed in a mass ratio of 9.5:70:190:0.4, reacted at 95°C for 4.5 hours, and after the reaction was completed, vacuum distillation was performed at 0.08 MPa and 67°C for 3.2 hours to obtain modified HTSO; Step (2) modified HTSO, amino-modified nano-silica, anhydrous ethanol and 0.01 mol / L hydrochloric acid aqueous solution were mixed in a mass ratio of 13:95:450:16, stirred, and reacted at 70°C for 5.5 hours. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried at 95°C for 6.5 hours to obtain HTSO-grafted nano-silica; Step (3) allyl succinic anhydride, HTSO-grafted nano-silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide were mixed in a mass ratio of 45:155:650:4.5:1.7, reacted at 87°C for 4 hours, filtered, washed with deionized water, and dried at 97°C for 5.5 hours to obtain modified nano-silica; Step (4) tetrahydrofuran, deionized water, modified nano-silica, amino-modified nano-montmorillonite and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride were mixed in a mass ratio of 2900:1250:50:95:80, reacted at 62°C for 8 hours, filtered, washed with deionized water, and dried at 85°C for 3.5 hours to obtain nano-montmorillonite grafted modified nano-silica; Step (5) In an Ar gas environment, the polypropylene is heated to 67°C and kept warm for 1.7 hours, the nano-montmorillonite grafted modified nano-silica and the initiator BPO are added, the mixture is stirred at a speed of 165 r / min for 8.5 minutes, the mixture is heated to 92°C and kept warm for 0.7 hours, the mixture is cooled to room temperature, extracted with acetone for 24 hours, and dried at a vacuum degree of 0.05 MPa and a temperature of 75°C for 19.5 hours to obtain modified polypropylene; Among them, the mass ratio of polypropylene, nano-montmorillonite grafted modified nano-silica and initiator BPO is 97:12.5:1.1; Step (6) melt-blending polypropylene, modified polypropylene, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant and calcium stearate in a twin-screw extruder in a mass ratio of 78:9:5:11.5:0.25:0.3, setting five temperature zones according to the forward direction of the materials, the temperatures in the temperature zones are 111° C., 131° C., 151° C., 171° C. and 191° C., respectively, and the speed of the twin-screw extruder is 150 r / min. After the blending is completed, the mixture is cooled to obtain an impact-resistant and highly transparent polypropylene material; The mass ratio of antioxidant 168 to antioxidant 1010 in the antioxidant is 1:1.

[0029] Example 5 This embodiment provides a method for preparing an impact-resistant and highly transparent polypropylene material, comprising the following steps: Step (1) HTSO, 1,2-epoxy-9-decene, anhydrous ethanol and chloroplatinic acid were mixed in a mass ratio of 10:80:220:0.5, reacted at 100°C for 4 hours, and after the reaction was completed, the mixture was distilled under reduced pressure at 0.08 MPa and 70°C for 3 hours to obtain modified HTSO; Step (2) modified HTSO, amino-modified nano-silica, anhydrous ethanol and 0.01 mol / L hydrochloric acid aqueous solution were mixed in a mass ratio of 14:100:500:18, stirred, and reacted at 75°C for 5 hours. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried at 100°C for 6 hours to obtain HTSO-grafted nano-silica; Step (3) allyl succinic anhydride, HTSO-grafted nano-silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide were mixed in a mass ratio of 50:180:750:5:2, reacted at 90°C for 3 hours, filtered, washed with deionized water, and dried at 100°C for 5 hours to obtain modified nano-silica; Step (4) tetrahydrofuran, deionized water, modified nano-silica, amino-modified nano-montmorillonite and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride were mixed in a mass ratio of 3200:1400:55:100:90, reacted at 65°C for 7h, filtered, washed with deionized water, and dried at 90°C for 3h to obtain nano-montmorillonite grafted modified nano-silica; Step (5) In an Ar gas environment, the polypropylene is heated to 70°C and kept warm for 1.5 hours, the nano-montmorillonite grafted modified nano-silica and the initiator BPO are added, the mixture is stirred at a speed of 180 r / min for 8 minutes, the mixture is heated to 95°C and kept warm for 0.5 hours, the mixture is cooled to room temperature, extracted with acetone for 24 hours, and dried at a vacuum degree of 0.05 MPa and a temperature of 80°C for 18 hours to obtain modified polypropylene; The mass ratio of polypropylene, nano-montmorillonite grafted modified nano-silica and initiator BPO is 100:15:1.3; Step (6) melt-blending polypropylene, modified polypropylene, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant and calcium stearate in a twin-screw extruder in a mass ratio of 80:10:6:12:0.3:0.35, setting five temperature zones according to the forward direction of the materials, the temperatures of the temperature zones are 115°C, 135°C, 155°C, 175°C and 195°C, respectively, and the speed of the twin-screw extruder is 140 r / min. After the blending is completed, the mixture is cooled to obtain an impact-resistant and highly transparent polypropylene material; The mass ratio of antioxidant 168 to antioxidant 1010 in the antioxidant is 1:1.

[0030] Example 6 This embodiment provides a method for preparing amino-modified nano-silica, comprising the following steps: Nano-silica, anhydrous ethanol and γ-aminoethylaminopropyltrimethoxysilane were mixed uniformly in a mass ratio of 20:1000:6, reacted at 80°C for 6 hours, and after the reaction was completed, centrifuged, washed with deionized water, and dried at 90°C for 5 hours to obtain amino-modified nano-silica.

[0031] Example 7 This embodiment provides a method for preparing amino-modified nano-montmorillonite, comprising the following steps: γ-Aminopropyltriethoxysilane was added to deionized water, heated to 85°C, nano-montmorillonite was added, stirred at 40 r / min for 4 h, cooled to room temperature, centrifuged, washed with deionized water, and dried at 100°C for 4 h to obtain amino-modified nano-montmorillonite; The mass ratio of γ-aminopropyltriethoxysilane, deionized water and nano-montmorillonite is (2-4):(150-240):(20-40).

[0032] Comparative Example 1 This comparative example provides a method for preparing an impact-resistant and highly transparent polypropylene material, comprising the following steps: Step (1) HTSO, 1,2-epoxy-9-decene, anhydrous ethanol and chloroplatinic acid were mixed in a mass ratio of 8:40:100:0.1, reacted at 80°C for 6 hours, and after the reaction was completed, vacuum distillation was performed at 0.08 MPa and 60°C for 4 hours to obtain modified HTSO; Step (2) modified HTSO, amino-modified nano-silica, anhydrous ethanol and 0.01 mol / L hydrochloric acid aqueous solution were mixed in a mass ratio of 10:80:300:10, stirred, and reacted at 55°C for 7 hours. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried at 80°C for 8 hours to obtain HTSO-grafted nano-silica; Step (3) allyl succinic anhydride, HTSO-grafted nano-silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide were mixed in a mass ratio of 30:80:350:3:1, reacted at 80°C for 7 hours, filtered, washed with deionized water, and dried at 90°C for 7 hours to obtain modified nano-silica; Step (4) tetrahydrofuran, deionized water, modified nano-silica, amino-modified nano-montmorillonite and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride were mixed in a mass ratio of 2000:800:35:80:50, reacted at 55°C for 11 hours, filtered, washed with deionized water, and dried at 70°C for 5 hours to obtain nano-montmorillonite grafted modified nano-silica; Step (5) polypropylene, nano-montmorillonite grafted modified nano-silica, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant and calcium stearate are melt-blended in a twin-screw extruder in a mass ratio of 75.68:0.32:2:10:0.1:0.15, five temperature zones are set according to the forward direction of the material, and the temperatures of the temperature zones are 100°C, 120°C, 140°C, 160°C and 180°C, respectively. The speed of the twin-screw extruder is 180 r / min. After the blending is completed, the material is cooled to obtain an impact-resistant and highly transparent polypropylene material; The mass ratio of antioxidant 168 to antioxidant 1010 in the antioxidant is 1:1.

[0033] Comparative Example 2 This comparative example provides a method for preparing an impact-resistant and highly transparent polypropylene material, comprising the following steps: Step (1) HTSO, 1,2-epoxy-9-decene, anhydrous ethanol and chloroplatinic acid were mixed in a mass ratio of 8:40:100:0.1, reacted at 80°C for 6 hours, and after the reaction was completed, vacuum distillation was performed at 0.08 MPa and 60°C for 4 hours to obtain modified HTSO; Step (2) modified HTSO, amino-modified nano-silica, anhydrous ethanol and 0.01 mol / L hydrochloric acid aqueous solution were mixed in a mass ratio of 10:80:300:10, stirred, and reacted at 55°C for 7 hours. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried at 80°C for 8 hours to obtain HTSO-grafted nano-silica; Step (3) allyl succinic anhydride, HTSO-grafted nano-silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide were mixed in a mass ratio of 30:80:350:3:1, reacted at 80°C for 7 hours, filtered, washed with deionized water, and dried at 90°C for 7 hours to obtain modified nano-silica; Step (4) melt-blending polypropylene, modified nano-silica, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant and calcium stearate in a twin-screw extruder in a mass ratio of 75.68:0.32:2:10:0.1:0.15, setting five temperature zones according to the forward direction of the materials, the temperatures of the temperature zones are 100°C, 120°C, 140°C, 160°C and 180°C, respectively, and the speed of the twin-screw extruder is 180 r / min. After the blending is completed, the mixture is cooled to obtain an impact-resistant and highly transparent polypropylene material; The mass ratio of antioxidant 168 to antioxidant 1010 in the antioxidant is 1:1.

[0034] Comparative Example 3 This comparative example provides a method for preparing an impact-resistant and highly transparent polypropylene material, comprising the following steps: Step (1) HTSO, 1,2-epoxy-9-decene, anhydrous ethanol and chloroplatinic acid were mixed in a mass ratio of 8:40:100:0.1, reacted at 80°C for 6 hours, and after the reaction was completed, vacuum distillation was performed at 0.08 MPa and 60°C for 4 hours to obtain modified HTSO; Step (2) modified HTSO, amino-modified nano-silica, anhydrous ethanol and 0.01 mol / L hydrochloric acid aqueous solution were mixed in a mass ratio of 10:80:300:10, stirred, and reacted at 55°C for 7 hours. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried at 80°C for 8 hours to obtain HTSO-grafted nano-silica; Step (3) allyl succinic anhydride, HTSO-grafted nano-silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide were mixed in a mass ratio of 30:80:350:3:1, reacted at 80°C for 7 hours, filtered, washed with deionized water, and dried at 90°C for 7 hours to obtain modified nano-silica; Step (4) melt-blending polypropylene, modified nano-silica, maleic anhydride grafted polypropylene, antioxidant and calcium stearate in a mass ratio of 85.68:0.32:2:0.1:0.15 in a twin-screw extruder, setting five temperature zones according to the forward direction of the materials, the temperatures of the temperature zones are 100°C, 120°C, 140°C, 160°C and 180°C, respectively, and the speed of the twin-screw extruder is 180 r / min. After the blending is completed, the mixture is cooled to obtain an impact-resistant and highly transparent polypropylene material; The mass ratio of antioxidant 168 to antioxidant 1010 in the antioxidant is 1:1.

[0035] The amino-modified nano-silica in Examples 1-5 of the present invention and Comparative Examples 1-3 all adopts the amino-modified nano-silica prepared in Example 6.

[0036] The amino-modified nano-montmorillonite in Examples 1-5 of the present invention and Comparative Example 1 all adopts the amino-modified nano-montmorillonite prepared in Example 7.

[0037] In the examples and comparative examples of the present invention, HTSO is 1,1,1,3,5,5,5-heptamethyltrisiloxane, which is from Suzhou Junxin Plastic Co., Ltd.; nano-silica is from Shanghai Yien Chemical Technology Co., Ltd.; 1,2-epoxy-9-decene is from Beijing Bailingwei Technology Co., Ltd., CAS No.: 85721-25-1; allyl succinic anhydride is from Guangdong Wengjiang Chemical Reagent Co., Ltd., CAS No.: 7539-12-0; nano-montmorillonite is from Shanghai Yuanye Biotechnology Co., Ltd., which is sodium-based and has a specific surface area of 20-40m 2 / g; polypropylene was purchased from PetroChina Daqing Petrochemical Company, model T30S, which is homopolymer polypropylene; maleic anhydride grafted polypropylene was purchased from Shanghai Rizhisheng New Technology Development Co., Ltd., model CMG9801; ethylene-octene copolymer elastomer was from Dongguan Maiyiduo Plastic Trading Co., Ltd.

[0038] The impact-resistant and highly transparent polypropylene materials prepared in Examples 1-5 and Comparative Examples 1-3 were tested, and the specific test results are as follows: (1) Charpy notched impact strength: The impact-resistant, highly transparent polypropylene materials prepared in Examples 1-5 and Comparative Examples 1-3 were tested according to the method specified in GB / T 1043.1-2008. The test was repeated three times, and the average value was recorded. The specific test results are shown in Table 1. Table 1 As can be seen from Table 1, the impact-resistant, highly transparent polypropylene material prepared by the present invention has good impact resistance, with Example 5 having the best performance. In the present invention, ethylene-octene copolymer elastomer (POE) is used as a toughening agent. Within a certain range, the higher the content, the more significant the toughening effect; maleic anhydride grafted polypropylene enhances the interface bonding between polypropylene and POE to prevent crack propagation, and the higher the content, the higher the interfacial stress transfer efficiency; the modified polypropylene has excellent compatibility with polypropylene, and the impact resistance of the modified polypropylene is better than that of polypropylene, that is, the higher the content of modified polypropylene, the better the impact resistance. Compared with Comparative Example 1, in Example 1, nano-montmorillonite grafted modified nano-silica contains unsaturated carbon-carbon double bonds, and reacts with polypropylene under the action of initiator BPO to obtain modified polypropylene. This connection method makes the compatibility better and the mechanical properties better, that is, the impact resistance of Example 1 is better than that of Comparative Example 1. Compared with Comparative Example 1, Comparative Example 2 lacks nano-montmorillonite, and its impact resistance is reduced. Compared with Comparative Example 2, Comparative Example 3 removes the POE toughening agent, so the impact resistance is reduced, that is, the simply supported beam notched impact strength value in Comparative Example 3 is lower than that in Comparative Example 2.

[0039] (2) Haze test: The test was carried out according to the method specified in GB / T2410-2008, wherein the thickness of the injection molded sheet was 1 mm, and the test was repeated three times, and the average value was recorded. The specific test results are shown in Table 2; Table 2 According to the test results in Table 2, the average haze value in Examples 1-5 is 4.79%, and the impact-resistant, highly transparent polypropylene material prepared in Example 5 has the lowest haze and the best transparency. Compared with Example 1, the compatibility and dispersibility of the nano-montmorillonite-grafted modified nano-silica in the polypropylene material are not as good as those in Example 1, so the haze value in Comparative Example 1 is greater than that in Example 1. Compared with Comparative Example 1, Comparative Example 2 lacks the nano-montmorillonite that acts as a nucleating agent, which weakens the ability to refine the grains and enhances light scattering, resulting in increased haze. In other words, the transparency of Comparative Example 1 is better than that of Comparative Example 2. Compared with Comparative Example 3, POE, as a flexible phase, destroys the crystallinity of polypropylene, reduces crystallinity, and thus reduces haze. Once the ethylene-octene copolymer elastomer is missing, the improvement in transparency is reduced, so the haze increases. The haze value in Comparative Example 3 is greater than that in Comparative Example 2.

[0040] (3) Flame retardant performance test: The test method refers to GB / T 2406.2-2009 Oxygen Index Method - Plastic Combustion Performance Test Method. The test results are shown in Table 3: Table 3 The test results in Table 3 show that the impact-resistant, highly transparent polypropylene material prepared by the present invention exhibits excellent flame retardancy, with an average limiting oxygen index of 28.72%. Compared to Example 1, the compatibility and dispersibility of the nano-montmorillonite-grafted nano-silica in the polypropylene material are reduced in Comparative Example 1, which is detrimental to flame retardancy. Therefore, the limiting oxygen index of Comparative Example 1 is lower than that of Example 1. Comparative Example 2 lacks the nano-montmorillonite, which promotes the formation of a dense expanded carbon layer and enhances thermal oxygen barrier properties. Without the nano-montmorillonite, the flame retardant effect is naturally reduced.

[0041] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for preparing an impact-resistant and highly transparent polypropylene material, characterized in that: The following steps are involved: Step (1) HTSO, 1,2-epoxy-9-decene and anhydrous ethanol are mixed, stirred, heated, chloroplatinic acid is added, reacted, and after the reaction is completed, vacuum distillation is performed to obtain modified HTSO; Step (2) mixing the modified HTSO, amino-modified nano-silica and anhydrous ethanol, stirring, adding a hydrochloric acid aqueous solution, heating for reaction, completing the reaction, filtering, washing, and drying to obtain HTSO-grafted nano-silica; Step (3) mixing allyl succinic anhydride, HTSO-grafted nano-silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide, heating to react, filtering, washing and drying after the reaction is completed to obtain modified nano-silica; Step (4) tetrahydrofuran, deionized water, modified nano-silica and amino-modified nano-montmorillonite are mixed, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride is added, and the mixture is heated for reaction. After the reaction is completed, the mixture is filtered, washed and dried to obtain nano-montmorillonite grafted modified nano-silica; Step (5) in an inert gas environment, heating the polypropylene, adding the nano-montmorillonite grafted modified nano-silica and an initiator, stirring, heating and keeping warm, cooling, extracting, and drying to obtain modified polypropylene; Step (6) melt-blending the polypropylene, modified polypropylene, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant and lubricant, extruding and cooling to obtain an impact-resistant and highly transparent polypropylene material.

2. The method for preparing an impact-resistant and highly transparent polypropylene material according to claim 1, characterized in that: In the step (1), the mass ratio of HTSO, 1,2-epoxy-9-decene, anhydrous ethanol and chloroplatinic acid is (8-10):(40-80):(100-220):(0.1-0.5); the reaction temperature is 80-100°C, and the reaction time is 4-6h.

3. The method for preparing an impact-resistant and highly transparent polypropylene material according to claim 1, characterized in that: In step (2), the mass ratio of modified HTSO, amino-modified nano-silica, anhydrous ethanol and hydrochloric acid aqueous solution is (10-14):(80-100):(300-500):(10-18), the reaction temperature is 55-75°C, and the reaction time is 5-7h.

4. The method for preparing an impact-resistant and highly transparent polypropylene material according to claim 1, characterized in that: In the step (3), the mass ratio of allyl succinic anhydride, HTSO-grafted nano-silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide is (30-50):(80-180):(350-750):(3-5):(1-2); the reaction temperature is 80-90°C, and the reaction time is 3-7h.

5. The method for preparing an impact-resistant and highly transparent polypropylene material according to claim 1, characterized in that: In the step (4), the mass ratio of tetrahydrofuran, deionized water, modified nano-silica, amino-modified nano-montmorillonite and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride is (2000-3200):(800-1400):(35-55):(80-100):(50-90); the reaction temperature is 55-65°C, and the reaction time is 7-11 hours.

6. The method for preparing an impact-resistant and highly transparent polypropylene material according to claim 1, characterized in that: In the step (5), the mass ratio of polypropylene, nano-montmorillonite grafted modified nano-silica and initiator is (90-100):(5-15):(0.5-1.3); the reaction temperature is 85-95°C, and the reaction time is 0.5-1.5h.

7. The method for preparing an impact-resistant and highly transparent polypropylene material according to claim 1, characterized in that: In the step (5), the initiator is BPO.

8. The method for preparing an impact-resistant and highly transparent polypropylene material according to claim 1, characterized in that: In the step (6), the mass ratio of polypropylene, modified polypropylene, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant and lubricant is (70-80):(6-10):(2-6):(10-12):(0.1-0.3):(0.15-0.35).

9. The method for preparing an impact-resistant and highly transparent polypropylene material according to claim 1, characterized in that: In the step (6), the antioxidant includes antioxidant 168 and antioxidant 1010; the mass ratio of antioxidant 168 to antioxidant 1010 is 1:

1.

10. An impact-resistant and highly transparent polypropylene material, characterized in that: The invention is prepared by the preparation method of the impact-resistant and highly transparent polypropylene material according to any one of claims 1 to 9.

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