A high weather-resistant light-shielding film and its preparation method

Abstract

This invention discloses a high weather-resistant light-shielding film and its preparation method, relating to the field of light-shielding film technology. It comprises the following components: polyethylene terephthalate, modified intercalated bentonite, carbon black, flake silica, vinyltris(β-methoxyethoxy)silane, carbon fiber, antioxidant, hydroxyl silicone oil, and nano-titanium dioxide. The polymer light-shielding film prepared by this invention not only has low light transmittance but also excellent weather resistance, significantly delaying the aging process. Through the synergistic effect of the components, when light enters the high weather-resistant light-shielding film, it is either scattered or absorbed by the surfaces of the modified intercalated bentonite, carbon black, and nano-titanium dioxide particles within the film. The scattering effect complicates the light propagation path in the medium, thereby significantly reducing light transmittance.

Description

Technical Field

[0001] This invention belongs to the field of light-shielding film technology, and in particular to a high weather-resistant light-shielding film and its preparation method. Background Technology

[0002] Light-shielding film is the raw material for producing light-shielding sheets for camera lenses. It is generally made into light-shielding sheets of corresponding size and shape through stamping and shearing processes. The main purpose of the light-shielding sheet is to control the amount of light during camera shooting and avoid the adverse effects of too much or too little light on shooting.

[0003] The purpose of a lens hood is to allow only the necessary imaging light to enter the camera lens, effectively preventing interference from light outside the shooting range. For example, when strong direct light from outside the shooting range shines on the lens surface, stray light will be generated due to the reflection of light on the outer surface and multiple internal mirrors of the lens. This will reduce the contrast and sharpness of the image, and may even produce halos and bokeh, disrupting the harmony of the image and failing to achieve the desired effect. A lens hood can solve this problem.

[0004] In existing technologies, light-blocking sheets are made from PET film. PET film is a relatively comprehensive film material with good airtightness and aroma retention, but its moisture resistance is only average, and its moisture permeability decreases at low temperatures. PET film has excellent mechanical properties; its toughness is the best among all thermoplastics, and its tensile strength and impact strength are relatively higher than those of ordinary films. It also has good stiffness and dimensional stability.

[0005] However, PET film has relatively poor weather resistance and is prone to aging. As the aging process occurs, the mechanical properties of PET film will be greatly reduced, which will greatly shorten the service life of PET film. This means that it cannot maintain a good light-blocking effect as a light-blocking sheet.

[0006] Based on this, the present invention improves the weather resistance of PET light-shielding film by further improving the existing technology. Summary of the Invention

[0007] The purpose of this invention is to provide a highly weather-resistant light-shielding film to overcome the shortcomings of the prior art.

[0008] The technical solution adopted in this invention is as follows:

[0009] A high weather-resistant light-shielding film, comprising the following components by weight: 80-85 parts polyethylene terephthalate, 10-16 parts modified intercalated bentonite, 8-14 parts carbon black, 1-3 parts flake silica, 1.5-2.5 parts vinyltris(β-methoxyethoxy)silane, 2-2.5 parts carbon fiber, 1-1.6 parts antioxidant, 1-1.8 parts hydroxyl silicone oil, and 2-3 parts nano titanium dioxide;

[0010] The average particle size of the carbon black particles is 20 μm.

[0011] As a further technical solution: the method for preparing modified intercalated bentonite includes the following steps:

[0012] (1) First, add bentonite to the alkaline solution and perform ultrasonic dispersion treatment for 5-8 minutes to obtain a mixed dispersion. Add the mixed dispersion to the reactor and then introduce inert gas into the reactor to remove the air inside the reactor.

[0013] (2) Add 5-hydroxymethylfurfural and castor oil to the mixed dispersion obtained in step (1) in sequence, then adjust the temperature to 68°C and keep it warm while stirring for 30 min;

[0014] (3) Add potassium permanganate to the above reaction vessel, adjust the temperature to 89°C, stir the reaction at 500 r / min for 4 hours, and let it stand for 30 min to obtain the reaction mixture;

[0015] (4) The reaction mixture obtained in step (3) is filtered, washed until neutral, and dried under vacuum to obtain modified intercalated bentonite;

[0016] The vacuum drying temperature is 50℃ and the time is 1 hour.

[0017] As a further technical solution: the alkaline solution in step (1) is a sodium hydroxide solution;

[0018] The sodium hydroxide solution has a mass fraction of 10%.

[0019] The bentonite is calcium-based bentonite;

[0020] The mixing ratio of calcium-based bentonite to sodium hydroxide solution is 20-30g:100mL.

[0021] As a further technical solution: the inert gas mentioned in step (1) is any one of nitrogen, neon or helium.

[0022] As a further technical solution: in step (2), the mixing ratio of 5-hydroxymethylfurfural, castor oil and mixed dispersion is 3-5g: 1-1.6g: 150mL.

[0023] As a further technical solution: in step (3), the mass ratio of potassium permanganate and 5-hydroxymethylfurfural is 1:2.

[0024] As a further technical solution: the method for preparing the sheet-like silica is as follows:

[0025] First, add polyvinylpyrrolidone to anhydrous ethanol at a mass ratio of 1:5 and stir to mix evenly to obtain a mixed solution.

[0026] Graphene was uniformly dispersed into the above mixed solution to obtain a composite solution;

[0027] The mixing ratio of graphene to the mixture is 4g:100mL;

[0028] Tetraethyl orthosilicate was added to the above composite solution and stirred at 300 r / min for 10 min. Then ammonia was added to adjust the pH of the mixture to 10.5. The mixture was stirred and reacted for 10 hours. Then the mixture was dried by rotary evaporation and washed until neutral to obtain the mixed reactant.

[0029] The mixed reactants obtained above were subjected to segmented heating treatment in an electric resistance furnace. First, the temperature was increased to 55°C at a heating rate of 10°C / s and held for 30 minutes. Then, the temperature was increased to 880°C at a heating rate of 20°C / s and held for 4 hours. After the furnace was allowed to cool naturally to room temperature, flake-shaped silicon dioxide was obtained.

[0030] As a further technical solution: the tetraethyl orthosilicate is added to the above composite liquid at a mass ratio of 1:12;

[0031] The ammonia water is saturated ammonia water.

[0032] As a further technical solution: the antioxidant is antioxidant 1010.

[0033] A method for preparing a highly weather-resistant light-shielding film includes the following steps:

[0034] a. Weigh out the following components according to the following weight ratios: polyethylene terephthalate, modified intercalated bentonite, carbon black, flake silica, vinyltris(β-methoxyethoxy)silane, carbon fiber, antioxidant, hydroxyl silicone oil, and nano titanium dioxide.

[0035] b. Add the above raw materials to a mixer and mix them to obtain a mixture.

[0036] c. The mixture prepared above is added to a twin-screw extruder for melt extrusion, then cast into a film, cooled, and PET film is obtained.

[0037] The thickness is 0.2mm.

[0038] Beneficial effects:

[0039] The polymer light-shielding film prepared by this invention not only has low light transmittance, but also excellent weather resistance, which can significantly delay the aging process.

[0040] Through the synergistic effect of the components, when light enters the high weather-resistant light-shielding film, it is either scattered or absorbed by the surface of the modified intercalated bentonite, carbon black, and nano titanium dioxide particles within the film. Under the effect of scattering, the propagation path of light in the medium becomes more complex, which in turn significantly reduces the light transmittance, thereby reducing the light transmittance of the high weather-resistant light-shielding film. The light transmittance of the high weather-resistant light-shielding film prepared by this invention is less than 1.8%.

[0041] This invention modifies bentonite in a specific way, so that the modified intercalated bentonite and nano-titanium dioxide particles have a high absorption capacity for the ultraviolet light region of light. It mainly absorbs ultraviolet light and effectively blocks ultraviolet light, thereby effectively reducing the aging effect of ultraviolet light on the light-shielding film and improving the weather resistance of the light-shielding film.

[0042] The sheet-like silica allows light to be refracted when it enters the high-weather-resistant light-shielding film from the air, thus directly changing the direction of propagation. After multiple refractions, the light transmittance is significantly reduced.

[0043] The modified intercalated bentonite introduced in this invention can act as a stress concentration point in the light-shielding film matrix. When the light-shielding film matrix is ​​subjected to external force, the shear stress around the modified intercalated bentonite particles is transferred, causing the connected matrix to undergo local yielding, absorbing more energy, and thus strengthening the toughened light-shielding film. Simultaneously, it can also act as a nucleating agent, promoting crystallization and resulting in a tighter and more ordered arrangement of PET molecular chains, enhancing intermolecular interactions and contributing to increased tensile strength. However, excessive introduction can hinder molecular chain movement and reduce tensile strength. Attached Figure Description

[0044] Figure 1 Bar charts showing the tensile strength of the specimens in the examples and comparative examples;

[0045] Figure 2 The figure shows the effect of different amounts of modified intercalated bentonite on the tensile strength of the light-shielding film. Detailed Implementation

[0046] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0047] Example 1

[0048] A high weather-resistant light-shielding film, comprising the following components by weight: 80 parts polyethylene terephthalate, 10 parts modified intercalated bentonite, 8 parts carbon black, 1 part flake silica, 1.5 parts vinyltris(β-methoxyethoxy)silane, 2 parts carbon fiber, 1 part antioxidant, 1 part hydroxyl silicone oil, and 2 parts nano titanium dioxide.

[0049] The average particle size of the carbon black particles is 20 μm.

[0050] The method for preparing modified intercalated bentonite includes the following steps:

[0051] (1) First, add bentonite to alkaline solution and perform ultrasonic dispersion treatment for 5 minutes to obtain mixed dispersion. Add the mixed dispersion to the reactor and then introduce inert gas into the reactor to remove the air inside the reactor.

[0052] (2) Add 5-hydroxymethylfurfural and castor oil to the mixed dispersion obtained in step (1) in sequence, then adjust the temperature to 68°C and keep it warm while stirring for 30 min;

[0053] (3) Add potassium permanganate to the above reaction vessel, adjust the temperature to 89°C, stir the reaction at 500 r / min for 4 hours, and let it stand for 30 min to obtain the reaction mixture;

[0054] (4) The reaction mixture obtained in step (3) is filtered, washed until neutral, and dried under vacuum to obtain modified intercalated bentonite;

[0055] The vacuum drying temperature is 50℃ and the time is 1 hour.

[0056] In step (1), the alkaline solution is a sodium hydroxide solution;

[0057] The sodium hydroxide solution has a mass fraction of 10%.

[0058] The bentonite is calcium-based bentonite;

[0059] The mixing ratio of calcium-based bentonite to sodium hydroxide solution is 20g:100mL.

[0060] The inert gas mentioned in step (1) is nitrogen.

[0061] In step (2), the mixing ratio of 5-hydroxymethylfurfural, castor oil, and mixed dispersion is 3g:1g:150mL.

[0062] In step (3), the mass ratio of potassium permanganate to 5-hydroxymethylfurfural is 1:2.

[0063] The method for preparing sheet-like silica is as follows:

[0064] First, add polyvinylpyrrolidone to anhydrous ethanol at a mass ratio of 1:5 and stir to mix evenly to obtain a mixed solution.

[0065] Graphene was uniformly dispersed into the above mixed solution to obtain a composite solution;

[0066] The mixing ratio of graphene to the mixture is 4g:100mL;

[0067] Tetraethyl orthosilicate was added to the above composite solution and stirred at 300 r / min for 10 min. Then ammonia was added to adjust the pH of the mixture to 10.5. The mixture was stirred and reacted for 10 hours. Then the mixture was dried by rotary evaporation and washed until neutral to obtain the mixed reactant.

[0068] The mixed reactants obtained above were subjected to segmented heating treatment in an electric resistance furnace. First, the temperature was increased to 55°C at a heating rate of 10°C / s and held for 30 minutes. Then, the temperature was increased to 880°C at a heating rate of 20°C / s and held for 4 hours. After the furnace was allowed to cool naturally to room temperature, flake-shaped silicon dioxide was obtained.

[0069] Tetraethyl orthosilicate was added to the above composite solution at a mass ratio of 1:12.

[0070] The ammonia water is saturated ammonia water.

[0071] The antioxidant is antioxidant 1010.

[0072] A method for preparing a highly weather-resistant light-shielding film includes the following steps:

[0073] a. Weigh out the following components according to the following weight ratios: polyethylene terephthalate, modified intercalated bentonite, carbon black, flake silica, vinyltris(β-methoxyethoxy)silane, carbon fiber, antioxidant, hydroxyl silicone oil, and nano titanium dioxide.

[0074] b. Add the above raw materials to a mixer and mix them to obtain a mixture.

[0075] c. The mixture prepared above is added to a twin-screw extruder for melt extrusion, then cast into a film, cooled, and PET film is obtained.

[0076] The thickness is 0.2mm.

[0077] Example 2

[0078] A high weather-resistant light-shielding film, comprising the following components by weight: 82 parts polyethylene terephthalate, 13 parts modified intercalated bentonite, 10 parts carbon black, 2 parts flake silica, 1.8 parts vinyltris(β-methoxyethoxy)silane, 2.2 parts carbon fiber, 1.3 parts antioxidant, 1.5 parts hydroxyl silicone oil, and 2.5 parts nano titanium dioxide;

[0079] The average particle size of the carbon black particles is 20 μm.

[0080] The method for preparing modified intercalated bentonite includes the following steps:

[0081] (1) First, add bentonite to alkaline solution and perform ultrasonic dispersion treatment for 6 minutes to obtain mixed dispersion. Add the mixed dispersion to the reactor and then introduce inert gas into the reactor to remove the air inside the reactor.

[0082] (2) Add 5-hydroxymethylfurfural and castor oil to the mixed dispersion obtained in step (1) in sequence, then adjust the temperature to 68°C and keep it warm while stirring for 30 min;

[0083] (3) Add potassium permanganate to the above reaction vessel, adjust the temperature to 89°C, stir the reaction at 500 r / min for 4 hours, and let it stand for 30 min to obtain the reaction mixture;

[0084] (4) The reaction mixture obtained in step (3) is filtered, washed until neutral, and dried under vacuum to obtain modified intercalated bentonite;

[0085] The vacuum drying temperature is 50℃ and the time is 1 hour.

[0086] In step (1), the alkaline solution is a sodium hydroxide solution;

[0087] The sodium hydroxide solution has a mass fraction of 10%.

[0088] The bentonite is calcium-based bentonite;

[0089] The mixing ratio of calcium-based bentonite to sodium hydroxide solution is 22g:100mL.

[0090] The inert gas mentioned in step (1) is nitrogen.

[0091] In step (2), the mixing ratio of 5-hydroxymethylfurfural, castor oil, and mixed dispersion is 3.5g:1.2g:150mL.

[0092] In step (3), the mass ratio of potassium permanganate to 5-hydroxymethylfurfural is 1:2.

[0093] The method for preparing sheet-like silica is as follows:

[0094] First, add polyvinylpyrrolidone to anhydrous ethanol at a mass ratio of 1:5 and stir to mix evenly to obtain a mixed solution.

[0095] Graphene was uniformly dispersed into the above mixed solution to obtain a composite solution;

[0096] The mixing ratio of graphene to the mixture is 4g:100mL;

[0097] Tetraethyl orthosilicate was added to the above composite solution and stirred at 300 r / min for 10 min. Then ammonia was added to adjust the pH of the mixture to 10.5. The mixture was stirred and reacted for 10 hours. Then the mixture was dried by rotary evaporation and washed until neutral to obtain the mixed reactant.

[0098] The mixed reactants obtained above were subjected to segmented heating treatment in an electric resistance furnace. First, the temperature was increased to 55°C at a heating rate of 10°C / s and held for 30 minutes. Then, the temperature was increased to 880°C at a heating rate of 20°C / s and held for 4 hours. After the furnace was allowed to cool naturally to room temperature, flake-shaped silicon dioxide was obtained.

[0099] Tetraethyl orthosilicate was added to the above composite solution at a mass ratio of 1:12.

[0100] The ammonia water is saturated ammonia water.

[0101] The antioxidant is antioxidant 1010.

[0102] A method for preparing a highly weather-resistant light-shielding film includes the following steps:

[0103] a. Weigh out the following components according to the following weight ratios: polyethylene terephthalate, modified intercalated bentonite, carbon black, flake silica, vinyltris(β-methoxyethoxy)silane, carbon fiber, antioxidant, hydroxyl silicone oil, and nano titanium dioxide.

[0104] b. Add the above raw materials to a mixer and mix them to obtain a mixture.

[0105] c. The mixture prepared above is added to a twin-screw extruder for melt extrusion, then cast into a film, cooled, and PET film is obtained.

[0106] The thickness is 0.2mm.

[0107] Example 3

[0108] A high weather-resistant light-shielding film, comprising the following components by weight: 83 parts polyethylene terephthalate, 14 parts modified intercalated bentonite, 12 parts carbon black, 2 parts flake silica, 1.8 parts vinyltris(β-methoxyethoxy)silane, 2.3 parts carbon fiber, 1.2 parts antioxidant, 1.5 parts hydroxyl silicone oil, and 2.5 parts nano titanium dioxide;

[0109] The average particle size of the carbon black particles is 20 μm.

[0110] The method for preparing modified intercalated bentonite includes the following steps:

[0111] (1) First, add bentonite to alkaline solution and perform ultrasonic dispersion treatment for 7 minutes to obtain mixed dispersion. Add the mixed dispersion to the reactor and then introduce inert gas into the reactor to remove the air inside the reactor.

[0112] (2) Add 5-hydroxymethylfurfural and castor oil to the mixed dispersion obtained in step (1) in sequence, then adjust the temperature to 68°C and keep it warm while stirring for 30 min;

[0113] (3) Add potassium permanganate to the above reaction vessel, adjust the temperature to 89°C, stir the reaction at 500 r / min for 4 hours, and let it stand for 30 min to obtain the reaction mixture;

[0114] (4) The reaction mixture obtained in step (3) is filtered, washed until neutral, and dried under vacuum to obtain modified intercalated bentonite;

[0115] The vacuum drying temperature is 50℃ and the time is 1 hour.

[0116] In step (1), the alkaline solution is a sodium hydroxide solution;

[0117] The sodium hydroxide solution has a mass fraction of 10%.

[0118] The bentonite is calcium-based bentonite;

[0119] The mixing ratio of calcium-based bentonite to sodium hydroxide solution is 28g:100mL.

[0120] The inert gas mentioned in step (1) is nitrogen.

[0121] In step (2), the mixing ratio of 5-hydroxymethylfurfural, castor oil, and mixed dispersion is 4g:1.4g:150mL.

[0122] In step (3), the mass ratio of potassium permanganate to 5-hydroxymethylfurfural is 1:2.

[0123] The method for preparing sheet-like silica is as follows:

[0124] First, add polyvinylpyrrolidone to anhydrous ethanol at a mass ratio of 1:5 and stir to mix evenly to obtain a mixed solution.

[0125] Graphene was uniformly dispersed into the above mixed solution to obtain a composite solution;

[0126] The mixing ratio of graphene to the mixture is 4g:100mL;

[0127] Tetraethyl orthosilicate was added to the above composite solution and stirred at 300 r / min for 10 min. Then ammonia was added to adjust the pH of the mixture to 10.5. The mixture was stirred and reacted for 10 hours. Then the mixture was dried by rotary evaporation and washed until neutral to obtain the mixed reactant.

[0128] The mixed reactants obtained above were subjected to segmented heating treatment in an electric resistance furnace. First, the temperature was increased to 55°C at a heating rate of 10°C / s and held for 30 minutes. Then, the temperature was increased to 880°C at a heating rate of 20°C / s and held for 4 hours. After the furnace was allowed to cool naturally to room temperature, flake-shaped silicon dioxide was obtained.

[0129] Tetraethyl orthosilicate was added to the above composite solution at a mass ratio of 1:12.

[0130] The ammonia water is saturated ammonia water.

[0131] The antioxidant is antioxidant 1010.

[0132] A method for preparing a highly weather-resistant light-shielding film includes the following steps:

[0133] a. Weigh out the following components according to the following weight ratios: polyethylene terephthalate, modified intercalated bentonite, carbon black, flake silica, vinyltris(β-methoxyethoxy)silane, carbon fiber, antioxidant, hydroxyl silicone oil, and nano titanium dioxide.

[0134] b. Add the above raw materials to a mixer and mix them to obtain a mixture.

[0135] c. The mixture prepared above is added to a twin-screw extruder for melt extrusion, then cast into a film, cooled, and PET film is obtained.

[0136] The thickness is 0.2mm.

[0137] Example 4

[0138] A high weather-resistant light-shielding film, comprising the following components by weight: 84 parts polyethylene terephthalate, 15 parts modified intercalated bentonite, 12 parts carbon black, 2 parts flake silica, 2 parts vinyltris(β-methoxyethoxy)silane, 2.1 parts carbon fiber, 1.6 parts antioxidant, 1 part hydroxyl silicone oil, and 3 parts nano titanium dioxide;

[0139] The average particle size of the carbon black particles is 20 μm.

[0140] The method for preparing modified intercalated bentonite includes the following steps:

[0141] (1) First, add bentonite to alkaline solution and perform ultrasonic dispersion treatment for 5 minutes to obtain mixed dispersion. Add the mixed dispersion to the reactor and then introduce inert gas into the reactor to remove the air inside the reactor.

[0142] (2) Add 5-hydroxymethylfurfural and castor oil to the mixed dispersion obtained in step (1) in sequence, then adjust the temperature to 68°C and keep it warm while stirring for 30 min;

[0143] (3) Add potassium permanganate to the above reaction vessel, adjust the temperature to 89°C, stir the reaction at 500 r / min for 4 hours, and let it stand for 30 min to obtain the reaction mixture;

[0144] (4) The reaction mixture obtained in step (3) is filtered, washed until neutral, and dried under vacuum to obtain modified intercalated bentonite;

[0145] The vacuum drying temperature is 50℃ and the time is 1 hour.

[0146] In step (1), the alkaline solution is a sodium hydroxide solution;

[0147] The sodium hydroxide solution has a mass fraction of 10%.

[0148] The bentonite is calcium-based bentonite;

[0149] The mixing ratio of calcium-based bentonite to sodium hydroxide solution is 30g:100mL.

[0150] The inert gas mentioned in step (1) is nitrogen.

[0151] In step (2), the mixing ratio of 5-hydroxymethylfurfural, castor oil, and mixed dispersion is 3-5g: 1-1.6g: 150mL.

[0152] In step (3), the mass ratio of potassium permanganate to 5-hydroxymethylfurfural is 1:2.

[0153] The method for preparing sheet-like silica is as follows:

[0154] First, add polyvinylpyrrolidone to anhydrous ethanol at a mass ratio of 1:5 and stir to mix evenly to obtain a mixed solution.

[0155] Graphene was uniformly dispersed into the above mixed solution to obtain a composite solution;

[0156] The mixing ratio of graphene to the mixture is 4g:100mL;

[0157] Tetraethyl orthosilicate was added to the above composite solution and stirred at 300 r / min for 10 min. Then ammonia was added to adjust the pH of the mixture to 10.5. The mixture was stirred and reacted for 10 hours. Then the mixture was dried by rotary evaporation and washed until neutral to obtain the mixed reactant.

[0158] The mixed reactants obtained above were subjected to segmented heating treatment in an electric resistance furnace. First, the temperature was increased to 55°C at a heating rate of 10°C / s and held for 30 minutes. Then, the temperature was increased to 880°C at a heating rate of 20°C / s and held for 4 hours. After the furnace was allowed to cool naturally to room temperature, flake-shaped silicon dioxide was obtained.

[0159] Tetraethyl orthosilicate was added to the above composite solution at a mass ratio of 1:12.

[0160] The ammonia water is saturated ammonia water.

[0161] The antioxidant is antioxidant 1010.

[0162] A method for preparing a highly weather-resistant light-shielding film includes the following steps:

[0163] a. Weigh out the following components according to the following weight ratios: polyethylene terephthalate, modified intercalated bentonite, carbon black, flake silica, vinyltris(β-methoxyethoxy)silane, carbon fiber, antioxidant, hydroxyl silicone oil, and nano titanium dioxide.

[0164] b. Add the above raw materials to a mixer and mix them to obtain a mixture.

[0165] c. The mixture prepared above is added to a twin-screw extruder for melt extrusion, then cast into a film, cooled, and PET film is obtained.

[0166] The thickness is 0.2mm.

[0167] Example 5

[0168] A high weather-resistant light-shielding film, comprising the following components by weight: 85 parts polyethylene terephthalate, 16 parts modified intercalated bentonite, 14 parts carbon black, 3 parts flake silica, 2.5 parts vinyltris(β-methoxyethoxy)silane, 2.5 parts carbon fiber, 1.6 parts antioxidant, 1.8 parts hydroxyl silicone oil, and 3 parts nano titanium dioxide;

[0169] The average particle size of the carbon black particles is 20 μm.

[0170] The method for preparing modified intercalated bentonite includes the following steps:

[0171] (1) First, add bentonite to the alkaline solution and perform ultrasonic dispersion treatment for 8 minutes to obtain a mixed dispersion. Add the mixed dispersion to the reactor and then introduce inert gas into the reactor to remove the air inside the reactor.

[0172] (2) Add 5-hydroxymethylfurfural and castor oil to the mixed dispersion obtained in step (1) in sequence, then adjust the temperature to 68°C and keep it warm while stirring for 30 min;

[0173] (3) Add potassium permanganate to the above reaction vessel, adjust the temperature to 89°C, stir the reaction at 500 r / min for 4 hours, and let it stand for 30 min to obtain the reaction mixture;

[0174] (4) The reaction mixture obtained in step (3) is filtered, washed until neutral, and dried under vacuum to obtain modified intercalated bentonite;

[0175] The vacuum drying temperature is 50℃ and the time is 1 hour.

[0176] In step (1), the alkaline solution is a sodium hydroxide solution;

[0177] The sodium hydroxide solution has a mass fraction of 10%.

[0178] The bentonite is calcium-based bentonite;

[0179] The mixing ratio of calcium-based bentonite to sodium hydroxide solution is 30g:100mL.

[0180] The inert gas mentioned in step (1) is nitrogen.

[0181] In step (2), the mixing ratio of 5-hydroxymethylfurfural, castor oil, and mixed dispersion is 5g:1.6g:150mL.

[0182] In step (3), the mass ratio of potassium permanganate to 5-hydroxymethylfurfural is 1:2.

[0183] The method for preparing sheet-like silica is as follows:

[0184] First, add polyvinylpyrrolidone to anhydrous ethanol at a mass ratio of 1:5 and stir to mix evenly to obtain a mixed solution.

[0185] Graphene was uniformly dispersed into the above mixed solution to obtain a composite solution;

[0186] The mixing ratio of graphene to the mixture is 4g:100mL;

[0187] Tetraethyl orthosilicate was added to the above composite solution and stirred at 300 r / min for 10 min. Then ammonia was added to adjust the pH of the mixture to 10.5. The mixture was stirred and reacted for 10 hours. Then the mixture was dried by rotary evaporation and washed until neutral to obtain the mixed reactant.

[0188] The mixed reactants obtained above were subjected to segmented heating treatment in an electric resistance furnace. First, the temperature was increased to 55°C at a heating rate of 10°C / s and held for 30 minutes. Then, the temperature was increased to 880°C at a heating rate of 20°C / s and held for 4 hours. After the furnace was allowed to cool naturally to room temperature, flake-shaped silicon dioxide was obtained.

[0189] Tetraethyl orthosilicate was added to the above composite solution at a mass ratio of 1:12.

[0190] The ammonia water is saturated ammonia water.

[0191] The antioxidant is antioxidant 1010.

[0192] A method for preparing a highly weather-resistant light-shielding film includes the following steps:

[0193] a. Weigh out the following components according to the following weight ratios: polyethylene terephthalate, modified intercalated bentonite, carbon black, flake silica, vinyltris(β-methoxyethoxy)silane, carbon fiber, antioxidant, hydroxyl silicone oil, and nano titanium dioxide.

[0194] b. Add the above raw materials to a mixer and mix them to obtain a mixture.

[0195] c. The mixture prepared above is added to a twin-screw extruder for melt extrusion, then cast into a film, cooled, and PET film is obtained.

[0196] The thickness is 0.2mm.

[0197] Comparative Example 1:

[0198] Based on Example 1, no modified intercalated bentonite is added, and the rest of the technical solutions remain unchanged.

[0199] Comparative Example 2:

[0200] Based on Example 1, the modified intercalated bentonite was replaced with unmodified bentonite, while the rest of the technical solutions remained unchanged.

[0201] test

[0202] The tensile strength of the example and comparative specimens was tested according to ASTM D638-03.

[0203] Table 1

[0204] Tensile strength (MPa) Example 1 36.7 Example 2 37.4 Example 3 37.1 Example 4 36.5 Example 5 36.1 Comparative Example 1 28.7 Comparative Example 2 30.4 Pure PET film 20.3

[0205] As can be seen from Table 1, the light-shielding film prepared by the present invention has high tensile strength.

[0206] UV aging resistance test: The UV aging resistance test was conducted on the sample specimens of the examples and comparative examples according to GB / T16422.2—1999 (maximum irradiation energy 60 kWh·m). -2 (Time period: 300 hours)

[0207] Table 2

[0208] Tensile strength (MPa) Example 1 31.5 Example 2 32.3 Example 3 32.0 Example 4 31.3 Example 5 31.2 Comparative Example 1 21.3 Comparative Example 2 23.7 Pure PET film 10.2

[0209] As can be seen from Table 2, the light-shielding film prepared by the present invention has excellent weather resistance.

[0210] Using Example 1 as the base sample, the effects of different amounts of modified intercalated bentonite added on the tensile strength of the light-shielding film were compared:

[0211] Table 3

[0212] Modified intercalated bentonite addition amount / parts by weight Tensile strength (MPa) 0 28.7 5 33.5 10 36.7 15 36.1 20 34.8 25 32.7

[0213] As shown in Table 3, the tensile strength of the light-shielding film first increases and then decreases with the increase of the amount of modified intercalated bentonite added.

[0214] Figure 1 Bar charts showing the tensile strength of the specimens in the examples and comparative examples;

[0215] Figure 2 The figure shows the effect of different amounts of modified intercalated bentonite on the tensile strength of the light-shielding film.

[0216] The above description is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified to have equivalent changes, shall be within the protection scope of the present invention as long as they do not exceed the spirit covered by the specification.

Claims

1. A highly weather-resistant light-shielding film, characterized in that, It is made of the following components by weight: 80-85 parts polyethylene terephthalate, 10-16 parts modified intercalated bentonite, 8-14 parts carbon black, 1-3 parts flake silica, 1.5-2.5 parts vinyltris(β-methoxyethoxy)silane, 2-2.5 parts carbon fiber, 1-1.6 parts antioxidant, 1-1.8 parts hydroxyl silicone oil, and 2-3 parts nano titanium dioxide; The average particle size of the carbon black particles is 20 μm. The modified intercalated bentonite was prepared by the following steps: (1) First, add bentonite to the alkaline solution and perform ultrasonic dispersion treatment for 5-8 minutes to obtain a mixed dispersion. Add the mixed dispersion to the reactor and then introduce inert gas into the reactor to remove the air inside the reactor. (2) Add 5-hydroxymethylfurfural and castor oil to the mixed dispersion obtained in step (1) in sequence, then adjust the temperature to 68°C and keep it warm while stirring for 30 min; (3) Add potassium permanganate to the above reaction vessel, adjust the temperature to 89°C, stir the reaction at 500 r / min for 4 hours, and let it stand for 30 min to obtain the reaction mixture; (4) The reaction mixture obtained in step (3) is filtered, washed until neutral, and dried under vacuum to obtain modified intercalated bentonite; The vacuum drying temperature is 50℃ and the time is 1 hour.

2. The high weather-resistant light-shielding film according to claim 1, characterized in that: In step (1), the alkaline solution is a sodium hydroxide solution; The sodium hydroxide solution has a mass fraction of 10%. The bentonite is calcium-based bentonite; The mixing ratio of calcium-based bentonite to sodium hydroxide solution is 20-30g:100mL.

3. The high weather-resistant light-shielding film according to claim 1, characterized in that: The inert gas mentioned in step (1) is any one of nitrogen, neon or helium.

4. The high weather-resistant light-shielding film according to claim 1, characterized in that: In step (2), the mixing ratio of 5-hydroxymethylfurfural, castor oil, and mixed dispersion is 3-5g: 1-1.6g: 150mL.

5. The high weather-resistant light-shielding film according to claim 1, characterized in that: In step (3), the mass ratio of potassium permanganate to 5-hydroxymethylfurfural is 1:

2.

6. The high weather-resistant light-shielding film according to claim 1, characterized in that: The sheet-like silica is prepared by the following method: First, add polyvinylpyrrolidone to anhydrous ethanol at a mass ratio of 1:5 and stir to mix evenly to obtain a mixed solution. Graphene was uniformly dispersed into the above mixed solution to obtain a composite solution; The mixing ratio of graphene to the mixture is 4g:100mL; Tetraethyl orthosilicate was added to the above composite solution and stirred at 300 r / min for 10 min. Then ammonia was added to adjust the pH of the mixture to 10.

5. The mixture was stirred and reacted for 10 hours. Then the mixture was dried by rotary evaporation and washed until neutral to obtain the mixed reactant. The mixed reactants obtained above were subjected to segmented heating treatment in an electric resistance furnace. First, the temperature was increased to 55°C at a heating rate of 10°C / s and held for 30 minutes. Then, the temperature was increased to 880°C at a heating rate of 20°C / s and held for 4 hours. After the furnace was allowed to cool naturally to room temperature, flake-shaped silicon dioxide was obtained.

7. The high weather-resistant light-shielding film according to claim 6, characterized in that: The tetraethyl orthosilicate was added to the above composite liquid at a mass ratio of 1:

12. The ammonia water is saturated ammonia water.

8. The high weather-resistant light-shielding film according to claim 1, characterized in that: The antioxidant is antioxidant 1010.

9. The method for preparing a high weather-resistant light-shielding film according to claim 1, characterized in that, Includes the following steps: a. Weigh out the following components according to the following weight ratios: polyethylene terephthalate, modified intercalated bentonite, carbon black, flake silica, vinyltris(β-methoxyethoxy)silane, carbon fiber, antioxidant, hydroxyl silicone oil, and nano titanium dioxide. b. Add the above raw materials to a mixer and mix them to obtain a mixture. c. The mixture prepared above is added to a twin-screw extruder for melt extrusion, then cast into a film, cooled, and PET film is obtained.

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