An impact-resistant high-transparency polypropylene material and a preparation method thereof

Abstract

The application discloses an anti-impact high-transparency polypropylene material and a preparation method thereof, and belongs to the technical field of polymer materials, and solves the problem that the transparency and anti-impact performance of the polypropylene material need to be further improved; the preparation method of the anti-impact high-transparency polypropylene material comprises the following steps: under an inert gas environment, polypropylene is heated, nano-montmorillonite grafted nano-silicon dioxide and an initiator are added, stirring, heating and heat preservation are conducted, and modified polypropylene is obtained; the polypropylene, the modified polypropylene, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, an antioxidant and a lubricant are melt blended, extruded, cooled, and the anti-impact high-transparency polypropylene material is obtained; the anti-impact high-transparency polypropylene material obtained by the application meets good anti-impact performance and high transparency, and also has good high-temperature resistance and flame retardance, and is beneficial to expansion of the use range.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to an impact-resistant, highly transparent polypropylene material and its preparation method. Background Technology

[0002] In recent years, the plastics industry has developed rapidly, and plastic products have been deeply integrated into all sectors of the national economy, with extremely diverse applications. Polypropylene, as a typical representative of general-purpose polymer materials, has gained widespread use in industry and daily life due to its advantages of low density, excellent electrical insulation, stable chemical properties, and low cost. However, its insufficient transparency cannot be ignored, which limits its applications. Adding nucleating agents during the production process can effectively improve the toughness and crystallization properties of polypropylene. Sorbitol-based nucleating agents release toxic formaldehyde gas during nucleation and have poor high-temperature resistance. Adding elastomers to polypropylene can improve impact resistance; as the elastomer content increases, impact resistance tends to increase, but haze increases, which is detrimental 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 its preparation method. The composition is prepared by mixing polypropylene resin, polyolefin elastomer, metallocene linear low-density polyethylene, weather-resistant additives, and colorants in a mass ratio of 100:(6-15):(12-38):(0.06-0.46):(0.002-0.015). The resulting impact-resistant, highly transparent polypropylene composition exhibits transparency and high impact resistance; however, the lowest haze level is 9.1%, which needs further improvement. Chinese patent CN112375304B discloses a transparent polypropylene material and its preparation method. The transparent polypropylene material comprises 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 improved, and the haze is relatively high, which limits its application. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an impact-resistant, highly transparent polypropylene material and its preparation method, which solves the problem that the transparency and impact resistance of polypropylene materials need to be further improved. The impact-resistant, highly transparent polypropylene material prepared by this invention has good impact resistance and high transparency, as well as good high temperature resistance and flame retardant properties, which is conducive to expanding its application range.

[0005] To achieve the above objectives, the present invention provides a method for preparing an impact-resistant, highly transparent polypropylene material, comprising the following steps:

[0006] Step (1) Mix HTSO, 1,2-epoxy-9-decene and anhydrous ethanol, stir, heat, add chloroplatinic acid, react, after the reaction is completed, distill under reduced pressure to obtain modified HTSO;

[0007] Step (2) Mix modified HTSO, amino-modified nano silica and anhydrous ethanol, stir, add hydrochloric acid aqueous solution, heat to react, filter, wash and dry to obtain HTSO grafted nano silica.

[0008] Step (3) Mix allyl succinic anhydride, HTSO-grafted nano silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide, heat to react, filter, wash and dry to obtain modified nano silica;

[0009] Step (4) Mix tetrahydrofuran, deionized water, modified nano silica and amino-modified nano montmorillonite, add 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, heat to react, filter, wash and dry to obtain nano montmorillonite grafted modified nano silica.

[0010] Step (5) In an inert gas environment, polypropylene is heated, nano-montmorillonite grafted modified nano-silica and initiator are added, stirred, heated and kept warm, cooled, extracted and dried to obtain modified polypropylene;

[0011] Step (6) involves melting and blending polypropylene, modified polypropylene, maleic anhydride-grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant, and lubricant, extruding, and cooling to obtain an impact-resistant, highly transparent polypropylene material.

[0012] Preferably, the preparation method of amino-modified nano-silica includes the following steps:

[0013] Nano-silica, anhydrous ethanol, and γ-aminoethylaminopropyltrimethoxysilane were mixed evenly, heated, and reacted. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain amino-modified nano-silica.

[0014] The mass ratio of nano-silica, anhydrous ethanol and γ-aminoethylaminopropyltrimethoxysilane is (20-40):(1000-2000):(6-8);

[0015] The reaction temperature is 60-80℃, and the reaction time is 4-6h.

[0016] Preferably, the preparation method of amino-modified nano-montmorillonite includes the following steps:

[0017] γ-aminopropyltriethoxysilane was added to deionized water, stirred and heated, nano-montmorillonite was added, the reaction was stirred, cooled, centrifuged, washed with deionized water, and dried to obtain amino-modified nano-montmorillonite.

[0018] The mass ratio of γ-aminopropyltriethoxysilane, deionized water and nano-montmorillonite is (2-4):(150-240):(20-40);

[0019] The reaction temperature is 85-95℃, and the reaction time is 3-4 hours.

[0020] The stirring speed is 20-40 r / min.

[0021] 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℃, and the reaction time is 4-6h.

[0022] 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℃, and the reaction time is 5-7h.

[0023] Preferably, the concentration of the hydrochloric acid aqueous solution is 0.01 mol / L.

[0024] Preferably, in 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℃ and the reaction time is 3-7h.

[0025] 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℃, and the reaction time is 7-11h.

[0026] 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℃ and the reaction time is 0.5-1.5h.

[0027] Preferably, in step (5), the initiator is BPO.

[0028] 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).

[0029] Preferably, the lubricant is calcium stearate.

[0030] Preferably, in step (6), the antioxidant includes antioxidant 168 and antioxidant 1010; the mass ratio of antioxidant 168 and antioxidant 1010 is 1:1.

[0031] Preferably, the melt blending is carried out in a twin-screw extruder, which is equipped with five temperature zones according to the material forward direction, with temperatures of 100-115℃, 120-135℃, 140-155℃, 160-175℃, and 180-195℃ respectively, and the rotation speed of the twin-screw extruder is 140-180 r / min.

[0032] An impact-resistant, highly transparent polypropylene material is prepared by the method described above.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] 1. The nano-silica added in this invention is an inorganic material with 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 uniformly 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 organosilane. After reacting with 1,2-epoxy-9-decene under Pt catalysis, modified HTSO is obtained. The epoxy groups in the modified HTSO undergo a ring-opening reaction with the amino groups in the amino-modified nano-silica to obtain HTSO-grafted nano-silica. The hydroxyl groups in the HTSO-grafted nano-silica react with the anhydrides in allyl succinic anhydride to obtain modified nano-silica. At this point, the modified nano-silica is compatible with polypropylene and its inorganic framework can be used to improve thermal stability and carbonization efficiency. In addition, 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.

[0035] 2. The nano-montmorillonite added in this invention acts as a nucleating agent, effectively refining crystalline particles, reducing light scattering, and improving transparency. As an inorganic particle, its appropriate addition can improve the mechanical properties of the polypropylene matrix material. Furthermore, during combustion, nano-montmorillonite forms a layered char layer, blocking oxygen and heat transfer. Its layered structure can also adsorb free radicals generated during combustion, inhibiting gas-phase combustion chain reactions and thus playing a flame-retardant role. Nano-montmorillonite is modified with γ-aminopropyltriethoxysilane to obtain amino-modified nano-montmorillonite. The amino groups in the amino-modified nano-montmorillonite react with the carboxyl groups in the modified nano-silica to obtain nano-montmorillonite grafted with modified nano-silica. Nano-silica and montmorillonite synergistically form a composite layer, improving char residue and exhibiting superior stability at high temperatures. The nitrogen element introduced in this invention also produces non-combustible gases during combustion, diluting the oxygen concentration in the combustion system and contributing to flame retardancy.

[0036] 3. In the preparation method of the impact-resistant, highly transparent polypropylene material provided by this invention, under the action of an initiator, the unsaturated double bonds in nano-montmorillonite-grafted modified nano-silica react with polypropylene to obtain modified polypropylene. Modified polypropylene exhibits good compatibility with polypropylene and facilitates the dispersion of functional particles, thereby enhancing overall mechanical properties. Ethylene-octene copolymer elastomer (POE), as a flexible phase, absorbs impact energy by initiating crazes / shear bands, improving the impact resistance of the matrix material. It also reduces the crystallinity of the polypropylene material, thus reducing haze. The compatibilizer, maleic anhydride-grafted polypropylene, improves the interfacial adhesion between the matrix and POE, effectively preventing crack propagation, enhancing interfacial stress transfer, and improving impact resistance. Attached Figure Description

[0037] Figure 1 This is a flowchart illustrating the preparation process of the impact-resistant, highly transparent polypropylene material in this invention.

[0038] Figure 2 This is a schematic diagram of the reaction for preparing modified HTSO in this invention;

[0039] Figure 3 This is a schematic diagram of the reaction for preparing HTSO-grafted nano-silica in this invention;

[0040] Figure 4 The above are bar graphs showing the notched impact strength test results of simply supported beams in Examples 1-5 and Comparative Examples 1-3 of this invention.

[0041] Figure 5 The above are bar charts showing the haze test results of Examples 1-5 and Comparative Examples 1-3 in this invention. Detailed Implementation

[0042] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Example 1

[0044] This embodiment provides a method for preparing an impact-resistant, highly transparent polypropylene material, including the following steps:

[0045] 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 and reacted at 80℃ for 6 hours. After the reaction was completed, the mixture was distilled under reduced pressure at 0.08MPa and 60℃ for 4 hours to obtain modified HTSO.

[0046] Step (2) Modified HTSO, amino-modified nano silica, anhydrous ethanol and 0.01 mol / L hydrochloric acid aqueous solution are mixed in a mass ratio of 10:80:300:10, stirred and reacted at 55℃ for 7 h. After the reaction is completed, the mixture is filtered, washed with deionized water and dried at 80℃ for 8 h to obtain HTSO grafted nano silica.

[0047] Step (3) Allyl succinic anhydride, HTSO-grafted nano silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide are mixed in a mass ratio of 30:80:350:3:1 and reacted at 80°C for 7 hours. After the reaction is completed, the mixture is filtered, washed with deionized water, and dried at 90°C for 7 hours to obtain modified nano silica.

[0048] 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 and reacted at 55°C for 11 h. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried at 70°C for 5 h to obtain nano montmorillonite grafted modified nano silica.

[0049] Step (5) In an Ar atmosphere, polypropylene is heated to 60°C and kept warm for 2.5 h. Nano-montmorillonite grafted modified nano-silica and initiator BPO are added. The mixture is stirred at 120 r / min for 10 min, heated to 85°C and kept warm for 1.5 h, cooled to room temperature, extracted with acetone for 24 h, and dried at 60°C under a vacuum of 0.05 MPa for 24 h to obtain modified polypropylene.

[0050] The mass ratio of polypropylene, nano-montmorillonite grafted modified nano-silica, and initiator BPO is 90:5:0.5.

[0051] Step (6) Polypropylene, modified polypropylene, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant and calcium stearate are melt-blended in a twin-screw extruder at a mass ratio of 70:6:2:10:0.1:0.15. Five temperature zones are set according to the material forward direction, with temperatures of 100℃, 120℃, 140℃, 160℃ and 180℃ respectively. The speed of the twin-screw extruder is 180 r / min. After blending, the mixture is cooled to obtain impact-resistant and highly transparent polypropylene material.

[0052] The antioxidants 168 and 1010 are in a mass ratio of 1:1.

[0053] Example 2

[0054] This embodiment provides a method for preparing an impact-resistant, highly transparent polypropylene material, including the following steps:

[0055] 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 and reacted at 85℃ for 5.5h. After the reaction was completed, the mixture was distilled under reduced pressure at 0.08MPa and 62℃ for 3.8h to obtain modified HTSO.

[0056] Step (2) Modified HTSO, amino-modified nano silica, anhydrous ethanol and 0.01 mol / L hydrochloric acid aqueous solution are mixed in a mass ratio of 11:85:350:12, stirred and reacted at 60℃ for 6.5 h. After the reaction is completed, the mixture is filtered, washed with deionized water and dried at 85℃ for 7.5 h to obtain HTSO grafted nano silica.

[0057] 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 and reacted at 82℃ for 6 hours. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried at 92℃ for 6.5 hours to obtain modified nano silica.

[0058] 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 and reacted at 57°C for 10 h. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried at 75°C for 4.5 h to obtain nano montmorillonite grafted modified nano silica.

[0059] Step (5) In an Ar atmosphere, polypropylene was heated to 62°C and kept warm for 2.2 h. Nano-montmorillonite grafted modified nano-silica and initiator BPO were added. The mixture was stirred at 135 r / min for 9.5 min, heated to 87°C and kept warm for 1.3 h, cooled to room temperature, extracted with acetone for 24 h, and dried at 65°C under a vacuum of 0.05 MPa for 22.5 h to obtain modified polypropylene.

[0060] The mass ratio of polypropylene, nano-montmorillonite grafted modified nano-silica, and initiator BPO is 92:7.5:0.7.

[0061] Step (6) Polypropylene, modified polypropylene, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant and calcium stearate are melt-blended in a twin-screw extruder at a mass ratio of 72:7:3:10.5:0.15:0.2. Five temperature zones are set according to the material forward direction, with temperatures of 103℃, 123℃, 143℃, 163℃ and 183℃ respectively. The speed of the twin-screw extruder is 170 r / min. After blending, the mixture is cooled to obtain impact-resistant and highly transparent polypropylene material.

[0062] The antioxidants 168 and 1010 are in a mass ratio of 1:1.

[0063] Example 3

[0064] This embodiment provides a method for preparing an impact-resistant, highly transparent polypropylene material, including the following steps:

[0065] 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 and reacted at 90℃ for 5h. After the reaction was completed, the mixture was distilled under reduced pressure at 0.08MPa and 65℃ for 3.5h to obtain modified HTSO.

[0066] Step (2) Modified HTSO, amino-modified nano silica, anhydrous ethanol and 0.01 mol / L hydrochloric acid aqueous solution are mixed in a mass ratio of 12:90:400:14, stirred and reacted at 65℃ for 6 h. After the reaction is completed, the mixture is filtered, washed with deionized water and dried at 90℃ for 7 h to obtain HTSO grafted nano silica.

[0067] Step (3) Allyl succinic anhydride, HTSO-grafted nano silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide are mixed in a mass ratio of 40:130:550:4:1.5 and reacted at 85°C for 5 hours. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried at 95°C for 6 hours to obtain modified nano silica.

[0068] 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 and reacted at 60°C for 9 h. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried at 80°C for 4 h to obtain nano montmorillonite grafted modified nano silica.

[0069] Step (5) In an Ar atmosphere, polypropylene is heated to 65°C and kept warm for 2 hours. Nano-montmorillonite grafted modified nano-silica and initiator BPO are added. The mixture is stirred at 150 r / min for 9 minutes, heated to 90°C and kept warm for 1 hour, cooled to room temperature, extracted with acetone for 24 hours, and dried at 70°C under a vacuum of 0.05 MPa for 21 hours to obtain modified polypropylene.

[0070] The mass ratio of polypropylene, nano-montmorillonite grafted modified nano-silica, and initiator BPO is 95:10:0.9.

[0071] Step (6) Polypropylene, modified polypropylene, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant and calcium stearate are melt-blended in a twin-screw extruder at a mass ratio of 75:8:4:11:0.2:0.25. Five temperature zones are set according to the material forward direction, with temperatures of 107℃, 127℃, 147℃, 167℃ and 187℃ respectively. The speed of the twin-screw extruder is 160 r / min. After blending, the mixture is cooled to obtain impact-resistant and highly transparent polypropylene material.

[0072] The antioxidants 168 and 1010 are in a mass ratio of 1:1.

[0073] Example 4

[0074] This embodiment provides a method for preparing an impact-resistant, highly transparent polypropylene material, including the following steps:

[0075] 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 and reacted at 95℃ for 4.5h. After the reaction was completed, the mixture was distilled under reduced pressure at 0.08MPa and 67℃ for 3.2h to obtain modified HTSO.

[0076] Step (2) Modified HTSO, amino-modified nano silica, anhydrous ethanol and 0.01 mol / L hydrochloric acid aqueous solution are mixed in a mass ratio of 13:95:450:16, stirred and reacted at 70℃ for 5.5 h. After the reaction is completed, the mixture is filtered, washed with deionized water and dried at 95℃ for 6.5 h to obtain HTSO grafted nano silica.

[0077] Step (3) Allyl succinic anhydride, HTSO-grafted nano silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide are mixed in a mass ratio of 45:155:650:4.5:1.7 and reacted at 87°C for 4 hours. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried at 97°C for 5.5 hours to obtain modified nano silica.

[0078] 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 and reacted at 62°C for 8 hours. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried at 85°C for 3.5 hours to obtain nano montmorillonite grafted modified nano silica.

[0079] Step (5) Under Ar atmosphere, polypropylene is heated to 67°C and kept at that temperature for 1.7h. Nano-montmorillonite grafted modified nano-silica and initiator BPO are added. The mixture is stirred at 165r / min for 8.5min, heated to 92°C and kept at that temperature for 0.7h, cooled to room temperature, extracted with acetone for 24h, and dried at 75°C under a vacuum of 0.05MPa for 19.5h to obtain modified polypropylene.

[0080] The mass ratio of polypropylene, nano-montmorillonite grafted modified nano-silica, and initiator BPO is 97:12.5:1.1.

[0081] Step (6) Polypropylene, modified polypropylene, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant and calcium stearate are melt-blended in a twin-screw extruder at a mass ratio of 78:9:5:11.5:0.25:0.3. Five temperature zones are set according to the material forward direction, with temperatures of 111℃, 131℃, 151℃, 171℃ and 191℃ respectively. The speed of the twin-screw extruder is 150 r / min. After blending, the mixture is cooled to obtain impact-resistant and highly transparent polypropylene material.

[0082] The antioxidants 168 and 1010 are in a mass ratio of 1:1.

[0083] Example 5

[0084] This embodiment provides a method for preparing an impact-resistant, highly transparent polypropylene material, including the following steps:

[0085] Step (1) HTSO, 1,2-epoxy-9-decene, anhydrous ethanol and chloroplatinic acid are mixed in a mass ratio of 10:80:220:0.5 and reacted at 100℃ for 4 hours. After the reaction is completed, the mixture is distilled under reduced pressure at 0.08MPa and 70℃ for 3 hours to obtain modified HTSO.

[0086] Step (2) Modified HTSO, amino-modified nano silica, anhydrous ethanol and 0.01 mol / L hydrochloric acid aqueous solution are mixed in a mass ratio of 14:100:500:18, stirred and reacted at 75℃ for 5 h. After the reaction is completed, the mixture is filtered, washed with deionized water and dried at 100℃ for 6 h to obtain HTSO grafted nano silica.

[0087] Step (3) Allyl succinic anhydride, HTSO-grafted nano silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide are mixed in a mass ratio of 50:180:750:5:2 and reacted at 90°C for 3 hours. After the reaction is completed, the mixture is filtered, washed with deionized water, and dried at 100°C for 5 hours to obtain modified nano silica.

[0088] 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 and reacted at 65°C for 7 h. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried at 90°C for 3 h to obtain nano montmorillonite grafted modified nano silica.

[0089] Step (5) In an Ar atmosphere, polypropylene is heated to 70°C and kept warm for 1.5 h. Nano-montmorillonite grafted modified nano-silica and initiator BPO are added. The mixture is stirred at 180 r / min for 8 min, heated to 95°C and kept warm for 0.5 h, cooled to room temperature, extracted with acetone for 24 h, and dried at 80°C under a vacuum of 0.05 MPa for 18 h to obtain modified polypropylene.

[0090] The mass ratio of polypropylene, nano-montmorillonite grafted modified nano-silica, and initiator BPO is 100:15:1.3.

[0091] Step (6) Polypropylene, modified polypropylene, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant and calcium stearate are melt-blended in a twin-screw extruder at a mass ratio of 80:10:6:12:0.3:0.35. Five temperature zones are set according to the material forward direction, with temperatures of 115℃, 135℃, 155℃, 175℃ and 195℃ respectively. The speed of the twin-screw extruder is 140 r / min. After blending, the mixture is cooled to obtain impact-resistant and highly transparent polypropylene material.

[0092] The antioxidants 168 and 1010 are in a mass ratio of 1:1.

[0093] Example 6

[0094] This embodiment provides a method for preparing amino-modified nano-silica, including the following steps:

[0095] Nano-silica, anhydrous ethanol, and γ-aminoethylaminopropyltrimethoxysilane were mixed evenly at a mass ratio of 20:1000:6 and reacted at 80°C for 6 hours. After the reaction was completed, the mixture was centrifuged, washed with deionized water, and dried at 90°C for 5 hours to obtain amino-modified nano-silica.

[0096] Example 7

[0097] This embodiment provides a method for preparing amino-modified nano-montmorillonite, including the following steps:

[0098] γ-aminopropyltriethoxysilane was added to deionized water and heated to 85°C. Nano-montmorillonite was added and stirred at 40 r / min for 4 h. After cooling to room temperature, the mixture was centrifuged, washed with deionized water, and dried at 100°C for 4 h to obtain amino-modified nano-montmorillonite.

[0099] The mass ratio of γ-aminopropyltriethoxysilane, deionized water and nano-montmorillonite is (2-4):(150-240):(20-40).

[0100] Comparative Example 1

[0101] This comparative example provides a method for preparing an impact-resistant, highly transparent polypropylene material, including the following steps:

[0102] 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 and reacted at 80℃ for 6 hours. After the reaction was completed, the mixture was distilled under reduced pressure at 0.08MPa and 60℃ for 4 hours to obtain modified HTSO.

[0103] Step (2) Modified HTSO, amino-modified nano silica, anhydrous ethanol and 0.01 mol / L hydrochloric acid aqueous solution are mixed in a mass ratio of 10:80:300:10, stirred and reacted at 55℃ for 7 h. After the reaction is completed, the mixture is filtered, washed with deionized water and dried at 80℃ for 8 h to obtain HTSO grafted nano silica.

[0104] Step (3) Allyl succinic anhydride, HTSO-grafted nano silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide are mixed in a mass ratio of 30:80:350:3:1 and reacted at 80°C for 7 hours. After the reaction is completed, the mixture is filtered, washed with deionized water, and dried at 90°C for 7 hours to obtain modified nano silica.

[0105] 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 and reacted at 55°C for 11 h. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried at 70°C for 5 h to obtain nano montmorillonite grafted modified nano silica.

[0106] 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 at a mass ratio of 75.68:0.32:2:10:0.1:0.15. Five temperature zones are set according to the material forward direction, with temperatures of 100℃, 120℃, 140℃, 160℃ and 180℃ respectively. The rotation speed of the twin-screw extruder is 180 r / min. After blending, the mixture is cooled to obtain impact-resistant and highly transparent polypropylene material.

[0107] The antioxidants 168 and 1010 are in a mass ratio of 1:1.

[0108] Comparative Example 2

[0109] This comparative example provides a method for preparing an impact-resistant, highly transparent polypropylene material, including the following steps:

[0110] 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 and reacted at 80℃ for 6 hours. After the reaction was completed, the mixture was distilled under reduced pressure at 0.08MPa and 60℃ for 4 hours to obtain modified HTSO.

[0111] Step (2) Modified HTSO, amino-modified nano silica, anhydrous ethanol and 0.01 mol / L hydrochloric acid aqueous solution are mixed in a mass ratio of 10:80:300:10, stirred and reacted at 55℃ for 7 h. After the reaction is completed, the mixture is filtered, washed with deionized water and dried at 80℃ for 8 h to obtain HTSO grafted nano silica.

[0112] Step (3) Allyl succinic anhydride, HTSO-grafted nano silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide are mixed in a mass ratio of 30:80:350:3:1 and reacted at 80°C for 7 hours. After the reaction is completed, the mixture is filtered, washed with deionized water, and dried at 90°C for 7 hours to obtain modified nano silica.

[0113] Step (4) Polypropylene, modified nano silica, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant and calcium stearate are melt-blended in a twin-screw extruder at a mass ratio of 75.68:0.32:2:10:0.1:0.15. Five temperature zones are set according to the material forward direction, with temperatures of 100℃, 120℃, 140℃, 160℃ and 180℃ respectively. The speed of the twin-screw extruder is 180 r / min. After blending, the mixture is cooled to obtain impact-resistant and highly transparent polypropylene material.

[0114] The antioxidants 168 and 1010 are in a mass ratio of 1:1.

[0115] Comparative Example 3

[0116] This comparative example provides a method for preparing an impact-resistant, highly transparent polypropylene material, including the following steps:

[0117] 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 and reacted at 80℃ for 6 hours. After the reaction was completed, the mixture was distilled under reduced pressure at 0.08MPa and 60℃ for 4 hours to obtain modified HTSO.

[0118] Step (2) Modified HTSO, amino-modified nano silica, anhydrous ethanol and 0.01 mol / L hydrochloric acid aqueous solution are mixed in a mass ratio of 10:80:300:10, stirred and reacted at 55℃ for 7 h. After the reaction is completed, the mixture is filtered, washed with deionized water and dried at 80℃ for 8 h to obtain HTSO grafted nano silica.

[0119] Step (3) Allyl succinic anhydride, HTSO-grafted nano silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide are mixed in a mass ratio of 30:80:350:3:1 and reacted at 80°C for 7 hours. After the reaction is completed, the mixture is filtered, washed with deionized water, and dried at 90°C for 7 hours to obtain modified nano silica.

[0120] Step (4) Polypropylene, modified nano silica, maleic anhydride grafted polypropylene, antioxidant and calcium stearate are melt-blended in a twin-screw extruder at a mass ratio of 85.68:0.32:2:0.1:0.15. Five temperature zones are set according to the material forward direction, with temperatures of 100℃, 120℃, 140℃, 160℃ and 180℃ respectively. The speed of the twin-screw extruder is 180 r / min. After blending, the mixture is cooled to obtain impact-resistant and highly transparent polypropylene material.

[0121] The antioxidants 168 and 1010 are in a mass ratio of 1:1.

[0122] In Examples 1-5 and Comparative Examples 1-3 of this invention, the amino-modified nano-silica was prepared using the amino-modified nano-silica obtained in Example 6.

[0123] The amino-modified nano-montmorillonite in Examples 1-5 and Comparative Example 1 of this invention were all prepared using the amino-modified nano-montmorillonite obtained in Example 7.

[0124] In the embodiments and comparative examples of this invention, HTSO is 1,1,1,3,5,5,5-heptamethyltrisiloxane, sourced from Suzhou Junxin Plastics Co., Ltd.; nano-silica is from Shanghai Yi'en 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; and nano-montmorillonite is from Shanghai Yuanye Biotechnology Co., Ltd., sodium-based, with a specific surface area of ​​20-40 m². 2 / g; Polypropylene was purchased from Daqing Petrochemical Company of China National Petroleum Corporation, 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 came from Dongguan Maiyiduo Plastics Trading Co., Ltd.

[0125] The impact-resistant, highly transparent polypropylene materials prepared in Examples 1-5 and Comparative Examples 1-3 were tested, and the specific test results are as follows:

[0126] (1) Notched impact strength of simply supported beams: The impact-resistant high-transparency polypropylene materials prepared in Examples 1-5 and Comparative Examples 1-3 were tested according to the method specified in GB / T1043.1-2008. The test was repeated three times and the average value was recorded. The specific test results are shown in Table 1.

[0127] Table 1

[0128]

[0129] As shown in Table 1, the impact-resistant, highly transparent polypropylene material prepared by this invention exhibits excellent impact resistance, with Example 5 showing the best performance. In this 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 reinforces the interface between polypropylene and POE, preventing crack propagation; the higher the content, the higher the interface stress transfer efficiency. The modified polypropylene exhibits excellent compatibility with polypropylene, and its impact resistance is superior to that of polypropylene; that is, the higher the content of modified polypropylene, the better the impact resistance. In Example 1 compared to Comparative Example 1, the nano-montmorillonite-grafted modified nano-silica contains unsaturated carbon-carbon double bonds, which react with polypropylene under the action of the initiator BPO to obtain modified polypropylene. This connection method results in better compatibility and superior mechanical properties; that is, the impact resistance of Example 1 is superior to that of Comparative Example 1. Compared to Comparative Example 1, Comparative Example 2 lacks nano-montmorillonite, resulting in reduced impact resistance. Compared to Comparative Example 2, Comparative Example 3 has a lower impact resistance due to the removal of the POE toughening agent. Specifically, the notched impact strength of the simply supported beam in Comparative Example 3 is lower than that in Comparative Example 2.

[0130] (2) Haze test: The test was conducted according to the method specified in GB / T2410-2008. The thickness of the injection molded sheet was 1 mm. The test was repeated three times and the average value was recorded. The specific test results are shown in Table 2.

[0131] Table 2

[0132]

[0133] According to the test results in Table 2, the average haze value of Examples 1-5 was 4.79%, with the impact-resistant, high-transparency polypropylene material prepared in Example 5 exhibiting the lowest haze and the best transparency performance. Compared to Example 1, Comparative Example 1 showed lower compatibility and dispersibility of nano-montmorillonite-grafted modified nano-silica in the polypropylene material, resulting in a higher haze value in Comparative Example 1 compared to Example 1. Compared to Comparative Example 1, Comparative Example 2 lacked nano-montmorillonite, which acts as a nucleating agent, weakening its ability to refine grains and increasing light scattering, leading to higher haze; therefore, Comparative Example 1 showed better transparency than Comparative Example 2. Compared to Comparative Example 3, POE, as a flexible phase, disrupted the crystallinity of polypropylene, reducing crystallinity and thus lowering haze. However, the absence of the ethylene-octene copolymer elastomer reduced its effect on improving transparency, resulting in increased haze; therefore, the haze value in Comparative Example 3 was higher than that in Comparative Example 2.

[0134] (3) Flame retardant performance test: The test method refers to GB / T 2406.2-2009 Oxygen Index Method - Test Method for Burning Performance of Plastics. The test results are shown in Table 3:

[0135] Table 3

[0136]

[0137] According to the test results in Table 3, the impact-resistant, highly transparent polypropylene material prepared by this invention has good flame retardancy, with an average limiting oxygen index of 28.72%. Compared with Example 1, Comparative Example 1 shows reduced compatibility and dispersibility of nano-montmorillonite-grafted modified nano-silica in the polypropylene material, which is detrimental to flame retardancy. Therefore, the limiting oxygen index of Comparative Example 1 is lower than that of Example 1. Compared with Comparative Example 1, Comparative Example 2 lacks nano-montmorillonite. Nano-montmorillonite promotes the formation of a dense, expanded char layer and enhances thermal and oxygen barrier properties; its absence naturally reduces the flame retardant effect.

[0138] Although 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 can 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 patent coverage of the present invention.

Claims

1. A method for preparing an impact-resistant, highly transparent polypropylene material, characterized in that, Includes the following steps: Step (1) Mix HTSO, 1,2-epoxy-9-decene, anhydrous ethanol and chloroplatinic acid in a mass ratio of (8-10):(40-80):(100-220):(0.1-0.5), stir, and react at 80-100℃ for 4-6 hours. After the reaction is completed, distill under reduced pressure to obtain modified HTSO. Wherein, HTSO is 1,1,1,3,5,5,5-heptamethyltrisiloxane; Step (2) Mix modified HTSO, amino-modified nano silica, anhydrous ethanol and hydrochloric acid aqueous solution in a mass ratio of (10-14):(80-100):(300-500):(10-18), react at 55-75℃ for 5-7h, filter, wash and dry to obtain HTSO-grafted nano silica. The concentration of the hydrochloric acid aqueous solution was 0.01 mol / L. Step (3) Allyl succinic anhydride, HTSO-grafted nano silica, N,N-dimethylformamide, 4-dimethylaminopyridine and potassium hydroxide are mixed in a mass ratio of (30-50):(80-180):(350-750):(3-5):(1-2) and reacted at 80-90℃ for 3-7h. After the reaction is completed, the mixture is filtered, washed and dried to obtain modified nano silica. Step (4) Mix tetrahydrofuran, deionized water, modified nano silica and amino-modified nano montmorillonite, add 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, react at 55-65℃ for 7-11h, after the reaction is completed, filter, wash and dry to obtain nano montmorillonite grafted modified nano silica. 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). Step (5) Under an inert gas environment, polypropylene is heated, nano-montmorillonite-grafted modified nano-silica and initiator are added, stirred, reacted at 85-95℃ for 0.5-1.5h, cooled, extracted, dried, and modified polypropylene is obtained. The mass ratio of polypropylene, nano-montmorillonite grafted modified nano-silica, and initiator is (90-100):(5-15):(0.5-1.3). Step (6) Polypropylene, modified polypropylene, maleic anhydride grafted polypropylene, ethylene-octene copolymer elastomer, antioxidant and lubricant are melt-blended in a mass ratio of (70-80):(6-10):(2-6):(10-12):(0.1-0.3):(0.15-0.35), extruded and cooled to obtain impact-resistant and highly transparent polypropylene material.

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

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

1.

4. An impact-resistant, highly transparent polypropylene material, characterized in that, It is prepared by the method for preparing impact-resistant, highly transparent polypropylene material according to any one of claims 1-3.

Images