Heat-resistant and weather-resistant PVC (polyvinyl chloride) film and preparation method thereof

Abstract

The invention relates to the technical field of high polymer materials, and provides a heat-resistant and weather-resistant PVC film and a preparation method thereof.The PVC film is prepared from, by weight, 90-110 parts of PVC, 50-70 parts of plasticizer, 5-12 parts of filler, 1-3 parts of calcium-zinc stabilizer, 0.1-0.5 part of antioxidant, 0.5-2 parts of light stabilizer and 0.2-1 part of ultraviolet light absorber. The PVC film provided by the invention has good weather resistance, heat resistance and aging resistance.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a heat-resistant and weather-resistant PVC film and its preparation method. Background Technology

[0002] Polyvinyl chloride (PVC) is one of the world's five major general-purpose plastics. Due to its various excellent properties, such as good mechanical properties, flame retardancy, corrosion resistance, and low price, PVC is widely used in various fields including chemical industry, construction, light industry, packaging, and agriculture. In salt pans, sudden rainfall necessitates the use of large-area, repeatedly rolled-up covering films, and PVC film, with its aforementioned superior properties, has become the preferred material for covering salt pans during salt production.

[0003] The PVC molecule contains relatively unstable and reactive Cl-. - The tendency to form double bonds in PVC resin reduces its weather resistance, making it susceptible to damage from ultraviolet rays in sunlight during outdoor use, leading to discoloration such as yellowing and reddening. Furthermore, the heat resistance of PVC needs improvement, and its mechanical properties decrease at high temperatures. Therefore, enhancing the weather and heat resistance of PVC is crucial. Adding fillers such as silica, carbon black, and titanium dioxide is a relatively simple and common method to address these deficiencies. However, these fillers generally suffer from poor dispersibility and can even negatively impact the properties of the PVC itself.

[0004] Patent CN 107627696 A discloses a heat-resistant decorative film and its preparation method. The decorative film includes a PVC film layer, a base fabric layer, and a heat-resistant layer. The heat-resistant layer contains components such as water-based silicone-acrylic resin, amino resin, sodium bicarbonate, polyethylene wax, nano-titanium dioxide, water-based polyisocyanate curing agent, magnesium stearate, polyoxypropylene glycerol ether, carboxymethyl cellulose, ammonium polyphosphate, and ceramic fiber. However, nano-titanium dioxide, carboxymethyl cellulose, and ceramic fiber all have poor dispersibility, which makes it impossible for the heat resistance of the decorative film to achieve the desired effect.

[0005] Therefore, there is an urgent need in the market for a PVC film with good weather resistance and heat resistance. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention uses PVC as the matrix material and incorporates fillers composed of modified carbon black and modified silica. Combined with calcium-zinc stabilizers, antioxidants, light stabilizers, and ultraviolet absorbers, a PVC film is synthesized, which solves the problem of poor dispersibility and compatibility of fillers in the PVC matrix, giving the PVC film good weather resistance and heat resistance.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The present invention provides a heat-resistant and weather-resistant PVC film, which, by weight, comprises the following raw materials: 90-110 parts of PVC, 50-70 parts of plasticizer, 5-12 parts of filler, 1-3 parts of calcium-zinc stabilizer, 0.1-0.5 parts of antioxidant, 0.5-2 parts of light stabilizer, and 0.2-1 parts of ultraviolet absorber.

[0008] In some embodiments of the present invention, the PVC is of type SG-3.

[0009] In some embodiments of the present invention, the plasticizer is a mixture of dioctyl phthalate and an environmentally friendly plasticizer.

[0010] Preferably, the plasticizer is a mixture of dioctyl phthalate and an environmentally friendly plasticizer in a mass ratio of 1:(0.2-0.5).

[0011] More preferably, the environmentally friendly plasticizer is a mixture of sebacic acid polyester and epoxidized soybean oleate octyl ester.

[0012] The applicant uses a compound of dioctyl phthalate, polyester plasticizer and environmentally friendly plasticizer in a certain mass ratio as a plasticizer, which has multiple advantages such as rapid plasticization, low temperature resistance and durability.

[0013] In some embodiments of the present invention, the filler is a mixture of modified carbon black and modified silica in a mass ratio of 1:(2-3).

[0014] In some embodiments of the present invention, the method for preparing the modified carbon black includes the following steps: Add carbon black to an aqueous ethanol solution, sonicate, add silane coupling agent, adjust pH to 4-5, stir, centrifuge, wash, and dry to obtain modified carbon black.

[0015] In some embodiments of the present invention, the method for preparing the modified silica includes the following steps: 1) Add soybean oil to a reaction vessel, add peracetic acid dropwise at 60-70℃, stir for 2-3 hours, separate the liquids, take the oil phase, wash, rotary evaporate, and dry to obtain product 1 for later use; 2) Mix product 1 from step 1) with silica, stir for 10-20 min, and stir at 80-100℃ for 30-50 min to obtain product 2 for later use; 3) Mix natural astaxanthin and ethyl acetate, pass in an inert gas through the mixture, stir for 1.5-2.5 h, add product 2 from step 2), pass in an inert gas through the mixture, stir at 40-50℃ for 50-70 min, and dry to obtain modified silica.

[0016] The average particle size of the silica is 80-100 nm.

[0017] In some embodiments of the present invention, in step 2), the mass ratio of the silica to product 1 is 1:(0.2-0.3).

[0018] Preferably, in step 2), the mass ratio of the silica to product 1 is 1:0.25.

[0019] In some embodiments of the present invention, in step 3), the mass ratio of product 2 to natural astaxanthin is 1:(0.04-0.06).

[0020] Preferably, in step 3), the mass ratio of product 2 to natural astaxanthin is 1:0.05.

[0021] Silica is widely used as a reinforcing filler in PVC film products due to its high strength, high heat resistance, and high stability. Silica can also improve the weather resistance of PVC film through physical shielding and free radical adsorption. However, the abundant active hydroxyl groups on the surface of silica give it a certain degree of hydrophilicity, which makes it incompatible with the PVC resin matrix and unable to disperse well. This greatly reduces the effect of silica on improving the heat resistance and weather resistance of PVC film.

[0022] On the one hand, the applicant prepared an epoxidized soybean oil with low epoxy degree (product 1) by controlling the reaction conditions, and used it to modify silica to improve the dispersibility of silica in PVC. Specifically, the epoxy groups in the low-epoxidized soybean oil can react with the hydroxyl groups on the surface of silica, thereby achieving a coupling modification of silica by the low-epoxidized soybean oil, thus improving the dispersibility of silica in PVC. Furthermore, the applicant's preparation of the low-epoxidized soybean oil helps reduce VOC emissions during the coupling modification of silica, improving the dispersibility of silica while ensuring the reaction proceeds smoothly. Environmentally friendly and green; on the other hand, the applicant introduced natural astaxanthin to modify silica. Natural astaxanthin has good diffusion properties, allowing it to come into contact with silica that has not been modified by low-epoxy soybean oil. The hydrophobic molecular chains of natural astaxanthin shield the hydroxyl groups on the surface of silica, weakening the aggregation between silica molecules and enhancing the interaction between silica and PVC. This improves the dispersibility of silica in PVC. Furthermore, the chemical structure of natural astaxanthin can promptly eliminate free radicals generated when PVC ages in the air, effectively delaying the aging process of PVC and enhancing the weather resistance of PVC film.

[0023] Furthermore, the applicant uses silane coupling agents to modify carbon black to improve its dispersibility, and blends modified carbon black and modified silica in a specific mass ratio to form a filler, which synergistically improves the mechanical properties, heat resistance and weather resistance of PVC film.

[0024] In some embodiments of the present invention, the antioxidant is a hindered phenolic antioxidant.

[0025] Preferably, the hindered phenolic antioxidant is antioxidant AO-80.

[0026] In another aspect, the present invention provides a method for preparing the heat-resistant and weather-resistant PVC film described in the above technical solution, comprising the following steps: Mix PVC, plasticizer, filler, calcium-zinc stabilizer, antioxidant, light stabilizer and ultraviolet absorber, heat to 110-115℃, then cool to 45-50℃, let stand, and then extrude, calender, stretch, cool and roll up to obtain heat-resistant and weather-resistant PVC film.

[0027] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention uses PVC as the matrix material and designs to add fillers composed of modified carbon black and modified silica. It combines calcium zinc stabilizer, antioxidant, light stabilizer and ultraviolet absorber to synthesize a PVC film. Through the synergistic effect between the components, the problem of poor dispersion and compatibility of fillers in PVC matrix is ​​solved, so that the PVC film has good weather resistance and heat resistance.

[0028] (2) In this invention, carbon black is modified with silane coupling agent to improve the dispersibility of carbon black. At the same time, low epoxy soybean oil is prepared and modified with natural astaxanthin to synthesize modified precipitated silica. This effectively improves the dispersibility of precipitated silica in PVC. Modified carbon black and modified precipitated silica are compounded in a specific mass ratio to form a filler, which plays a synergistic role in improving the mechanical properties, heat resistance and weather resistance of PVC film. Detailed Implementation

[0029] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0030] In the following examples and comparative examples, except for modified carbon black and modified silica, all other compound monomers and related reagents used were commercially available. Among them, the PVC was SG-3 type, purchased from Yuyao Tongyuan Plastics Co., Ltd.; the sebacic acid polyester was propylene glycol sebacic acid polyester; the average particle size of the silica was 80 nm; the soybean oil was purchased from Jiangxi Huanqiu Natural Fragrance Co., Ltd.; the natural astaxanthin was purchased from Xi'an Baichuan Biotechnology Co., Ltd.; and the calcium-zinc stabilizer was purchased from Shandong Yunxin New Material Technology Co., Ltd.

[0031] Preparation Example 1 The preparation method of modified carbon black includes the following steps: Add 10g of carbon black to 200ml of ethanol-water solution (ethanol to deionized water volume ratio of 9:1), sonicate for 30min, add 1g of silane coupling agent KH550, add glacial acetic acid to adjust pH to 4.5, stir at 60℃ for 4h, centrifuge, wash three times alternately with anhydrous ethanol and deionized water, and dry to obtain modified carbon black.

[0032] Preparation Example 2 The synthesis method of modified silica A includes the following steps: (1) Add 10g of soybean oil to the reaction vessel, add 2g of peracetic acid dropwise at 65℃, stir for 2.5h, separate the liquid and take the oil phase, wash twice with 90℃ deionized water, wash four times with 10wt% sodium carbonate aqueous solution, wash twice with 90℃ deionized water, evaporate by rotary evaporation, and dry at 60℃ for 12h to obtain product 1 for later use. 2) Mix 5g of product 1 from step 1) with 20g of silica, stir for 15 minutes, and stir at 90℃ for 40 minutes to obtain product 2 for later use. 3) Mix 1g of natural astaxanthin and 200ml of ethyl acetate, introduce N2, stir for 2h, add 20g of product 2 from step 2), introduce N2, stir at 45℃ for 60min, and dry at 30℃ to constant weight to obtain modified silica A.

[0033] Preparation Example 3 Modified silica B is implemented in the same way as modified silica A, except that in step 2), the mass of product 1 is replaced with 7g.

[0034] Preparation Example 4 Modified silica C is implemented in the same way as modified silica A, except that in step 3), the mass of natural astaxanthin is replaced with 1.5g.

[0035] Example 1 A heat-resistant and weather-resistant PVC film, by weight, comprises the following raw materials: 100 parts PVC, 60 parts plasticizer, 8 parts filler, 2 parts calcium-zinc stabilizer, 0.3 parts antioxidant AO-80, 1 part light stabilizer 622, and 0.6 parts ultraviolet absorber UV-531.

[0036] The plasticizer is a mixture of dioctyl phthalate, propylene glycol sebacate polyester, and epoxidized soybean oleate octyl ester in a mass ratio of 1:0.2:0.15.

[0037] The filler is a mixture of modified carbon black and modified silica A in a mass ratio of 1:2.5.

[0038] The method for preparing the heat-resistant and weather-resistant PVC film in this embodiment includes the following steps: Mix PVC, plasticizer, filler, calcium zinc stabilizer, antioxidant AO-80, light stabilizer 622 and ultraviolet absorber UV-531, heat to 115℃, then cool to 45℃, let stand for 24 hours, extrude through a screw extruder, calender, stretch, cool, and roll up to obtain a heat-resistant and weather-resistant PVC film. During the extrusion process of the screw extruder, the temperature in zone one is 185℃, the temperature in zone two is 155℃, and the temperature in zone three is 170℃. The calendering process is a five-roll calendering process: Roll #1 temperature is 191℃, linear speed is 9.7m / min; Roll #2 temperature is 190℃, linear speed is 10.9m / min; Roll #3 temperature is 193℃, linear speed is 12.8m / min; Roll #4 temperature is 204℃, linear speed is 14.3m / min; Roll #5 temperature is 200℃, linear speed is 15.8m / min. The cooling system consists of four stages, with cooling temperatures of 55℃, 50℃, 45℃, and 36℃ respectively.

[0039] Example 2 A heat-resistant and weather-resistant PVC film, by weight, comprises the following raw materials: 90 parts PVC, 50 parts plasticizer, 5 parts filler, 1 part calcium-zinc stabilizer, 0.1 parts antioxidant AO-80, 0.5 parts light stabilizer 622, and 0.2 parts ultraviolet absorber UV-531.

[0040] The plasticizer is a mixture of dioctyl phthalate, propylene glycol sebacate polyester, and epoxidized soybean oleate octyl ester in a mass ratio of 1:0.1:0.1.

[0041] The filler is a mixture of modified carbon black and modified silica A in a mass ratio of 1:2.

[0042] The preparation method of the heat-resistant and weather-resistant PVC film in this embodiment is the same as that in Example 1.

[0043] Example 3 A heat-resistant and weather-resistant PVC film, by weight, comprises the following raw materials: 110 parts PVC, 70 parts plasticizer, 12 parts filler, 3 parts calcium-zinc stabilizer, 0.5 parts antioxidant AO-80, 2 parts light stabilizer 622, and 1 part ultraviolet absorber UV-531.

[0044] The plasticizer is a mixture of dioctyl phthalate, propylene glycol sebacate polyester, and epoxidized soybean oleate octyl ester in a mass ratio of 1:0.3:0.2.

[0045] The filler is a mixture of modified carbon black and modified silica A in a mass ratio of 1:3.

[0046] The preparation method of the heat-resistant and weather-resistant PVC film in this embodiment is the same as that in Example 1.

[0047] Example 4 This embodiment provides a heat-resistant and weather-resistant PVC film and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that the mass ratio of modified carbon black and modified silica A in the filler is 1:1.

[0048] Example 5 This embodiment provides a heat-resistant and weather-resistant PVC film and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that the filler is replaced by an equal amount of modified carbon black.

[0049] Example 6 This embodiment provides a heat-resistant and weather-resistant PVC film and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that the filler is replaced by an equal amount of modified silica A.

[0050] Example 7 This embodiment provides a heat-resistant and weather-resistant PVC film and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that modified silica A is replaced by modified silica B in an equal amount.

[0051] Example 8 This embodiment provides a heat-resistant and weather-resistant PVC film and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that modified silica A is replaced by modified silica C in an equal amount.

[0052] Example 9 This embodiment provides a heat-resistant and weather-resistant PVC film and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that modified silica A is replaced by silica in an equal amount.

[0053] Performance testing The heat resistance and weather resistance properties of the heat-resistant and weather-resistant PVC films of Examples 1-9 were tested, and the test results are shown in Table 1.

[0054] The mechanical properties of PVC film after high-temperature treatment and aging treatment are tested to determine the quality of its heat resistance and weather resistance. The mechanical properties are tested by taking tensile strength as an example, referring to the standard GB / T1040.3-2006.

[0055] (1) Heat resistance The PVC films of Examples 1-9 were placed at 200°C and left to stand for 24 hours to test their mechanical properties.

[0056] (2) Weather resistance The PVC films from Examples 1-9 were placed at 60°C with an ultraviolet irradiation intensity of 50 μW / cm². 2 The PVC film was subjected to accelerated aging in an aging chamber for 10 days, and then the aged PVC film was used for mechanical property testing.

[0057] Table 1 As shown in Table 1, the PVC films in Examples 1-3 of this invention still maintain good tensile strength after high-temperature treatment and aging treatment, with only a slight decrease compared to the untreated films, indicating good heat resistance and aging resistance. Specifically, Example 4 changed the addition ratio of modified carbon black and modified silica A in the filler; Examples 5 and 6 respectively showed no modified silica A and modified carbon black added to the filler, reducing the synergistic effect between the two, thus resulting in a certain degree of decrease in the heat resistance and weather resistance of the PVC film; Examples 7-8 changed the modification ratio of low-epoxy soybean oil and natural astaxanthin to silica during the preparation of modified silica, reducing the dispersibility of the prepared modified silica in PVC, thus leading to a significant decrease in the overall heat resistance and weather resistance of the PVC film; Example 9 used silica to replace modified silica A in an equal amount, and tests showed that the heat resistance and weather resistance of the PVC film were even worse.

[0058] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A heat-resistant and weather-resistant PVC film, characterized in that, By weight, the PVC film comprises the following raw materials: 90-110 parts PVC, 50-70 parts plasticizer, 5-12 parts filler, 1-3 parts calcium-zinc stabilizer, 0.1-0.5 parts antioxidant, 0.5-2 parts light stabilizer, and 0.2-1 parts ultraviolet absorber.

2. The heat-resistant and weather-resistant PVC film according to claim 1, characterized in that, The PVC is of type SG-3.

3. The heat-resistant and weather-resistant PVC film according to claim 1, characterized in that, The plasticizer is a mixture of dioctyl phthalate and an environmentally friendly plasticizer.

4. The heat-resistant and weather-resistant PVC film according to claim 1, characterized in that, The filler is a mixture of modified carbon black and modified silica, with a mass ratio of 1:(2-3).

5. The heat-resistant and weather-resistant PVC film according to claim 4, characterized in that, The method for preparing the modified carbon black includes the following steps: Add carbon black to an aqueous ethanol solution, sonicate, add silane coupling agent, adjust pH to 4-5, stir, centrifuge, wash, and dry to obtain modified carbon black.

6. The heat-resistant and weather-resistant PVC film according to claim 4, characterized in that, The method for preparing the modified silica includes the following steps: 1) Add soybean oil to a reaction vessel, add peracetic acid dropwise at 60-70℃, stir for 2-3 hours, separate the liquids, take the oil phase, wash, rotary evaporate, and dry to obtain product 1 for later use; 2) Mix product 1 from step 1) with silica, stir for 10-20 min, and stir at 80-100℃ for 30-50 min to obtain product 2 for later use; 3) Mix natural astaxanthin and ethyl acetate, pass in an inert gas through the mixture, stir for 1.5-2.5 h, add product 2 from step 2), pass in an inert gas through the mixture, stir at 40-50℃ for 50-70 min, and dry to obtain modified silica.

7. The heat-resistant and weather-resistant PVC film according to claim 6, characterized in that, In step 2), the mass ratio of the silica to product 1 is 1:(0.2-0.3).

8. The heat-resistant and weather-resistant PVC film according to claim 6, characterized in that, In step 3), the mass ratio of product 2 to natural astaxanthin is 1:(0.04-0.06).

9. The heat-resistant and weather-resistant PVC film according to claim 1, characterized in that, The antioxidant is a hindered phenolic antioxidant.

10. A method for preparing a heat-resistant and weather-resistant PVC film according to any one of claims 1-9, characterized in that, Includes the following steps: Mix PVC, plasticizer, filler, calcium-zinc stabilizer, antioxidant, light stabilizer and ultraviolet absorber, heat to 110-115℃, then cool to 45-50℃, let stand, and then extrude, calender, stretch, cool and roll up to obtain heat-resistant and weather-resistant PVC film.

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