A kind of impermeable PVC stretch film and its production process

Abstract

The application discloses a kind of anti-permeation PVC stretch film and production process thereof, belong to PVC stretch film technical field, by nitrogen-doped bentonite powder is compounded with titanium dioxide, bentonite can improve the rheological property of resin, to improve the processing performance of resin, by introducing nitrogen atom into the lattice of bentonite or surface, can significantly affect the charge state of bentonite, improve the compatibility of bentonite and resin matrix, nitrogen element doped on the surface of bentonite can improve the spectral absorption range and light absorption capacity of titanium dioxide, further improve the reflection and scattering of ultraviolet, by the synergistic effect between each other, overcome while ensuring good transparency, can long-term stable play a role;In epoxy composite bentonite powder molecule, epoxy group can terminate the free radical reaction of PVC degradation, improve the stability of PVC stretch film, prolong service life.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of PVC calendering film, and particularly relates to a permeation-proof PVC calendering film and a production process thereof. BACKGROUND

[0002] Polyvinyl chloride (PVC) and polyethylene (PE), polypropylene (PP), polystyrene (PS) and ABS resin are collectively referred to as five general resins, and the PVC calendering film is a film with a certain thickness, width and surface smoothness prepared through subsequent processes such as voltage, lamination, gluing, inflation, flocking and printing after PVC resin and fillers are subjected to the processes, and the thickness of the film is generally less than 0.25 mm, the film has good permeation-proof effect, and is widely used in various aspects such as inflatable toys, inflatable boats, swim rings, inflatable beds, umbrellas, stationery covers, tablecloths and shower curtains according to different uses.

[0003] Some PVC calendering film products are used as tablecloths outdoors, and due to poor weather resistance, the products are greatly affected by natural environment, and are prone to yellowing and aging when exposed to strong sunlight, rain and other harsh environments for a long time, thereby reducing the service life.

[0004] In order to increase the use performance of the PVC calendering film, fillers and other additives need to be added in the production process. A Chinese patent with the publication number CN107383421A discloses a preparation method of titanium dioxide special for PVC calendering film, a three-phase mixture of far-infrared ceramic powder, zinc oxide and titanium dioxide is subjected to a silicon dioxide layer coating and further organic surface modification to obtain modified titanium dioxide, and the surface of the modified titanium dioxide is treated by hydroxybenzoic acid and sodium silicate, the hydroxybenzoic acid has good dispersion effect on the titanium dioxide, and the compatibility of the modified titanium dioxide with the film resin is promoted, but the hydroxybenzoic acid may be obviously decomposed at a high processing temperature of some PVC calendering film products, the compatibility of the above-mentioned titanium dioxide special for calendering film with the PVC matrix is reduced, the distribution is uneven, and thus the processing performance of the PVC calendering film is reduced. SUMMARY

[0005] The application aims to provide a permeation-proof PVC calendering film and a production process thereof, the nitrogen-doped bentonite powder is compounded with titanium dioxide, the bentonite can improve the rheological property of the resin, thereby improving the processing performance of the resin, the nitrogen atom is introduced into the crystal lattice or the surface of the bentonite, the charge state of the bentonite is significantly affected, the compatibility of the bentonite with the resin matrix is improved, meanwhile, the hydroxybenzoic acid does not need to be added as a compatibility agent, and the processing performance is good, and the decomposition of the compatibility agent at a high temperature is avoided to reduce the processing performance of the product.

[0006] The object of the application can be achieved by the following technical scheme.

[0007] The production process of the anti-permeation PVC stretch film is prepared by the following steps:

[0008] Step one: add sulfonated composite bentonite powder, p-hydroxyaniline and deionized water into the reaction kettle, stir at 50-60℃ and 400-500r / min for 1-2h, add epichlorohydrin into the reaction kettle, stir at 50-60℃ and 400-500r / min for 30-50min, add 50-60wt% potassium hydroxide solution and tetrabutylammonium bromide into the reaction kettle, stir at 50-60℃ and 400-500r / min for 24-26h, filter, wash the filter cake with deionized water and anhydrous ethanol for 2-3 times respectively, vacuum dry at 60-80℃ for 1-2h, and get the epoxy composite bentonite powder.

[0009] Step two: mix the fluorinated modified PVC resin, epoxy composite bentonite powder, methyl tin stabilizer and zinc stearate uniformly according to the mass ratio of 90-100:10-15:1-3:2-3, then mix and plasticize the obtained sheet material by using a double roller open mill at 180-190℃ for 10-12min, and then use a four-roll calender device to calender and form the sheet material at 180-190℃, spray the non-fluorine waterproof and oil-proof agent on the surface of the formed eye pressure film according to the amount of 200-300mL / m 2 , dry at 50-60℃ for 50-80min, cool and roll up, and get an anti-permeation PVC stretch film.

[0010] Further, the amount ratio of sulfonated composite bentonite powder, p-hydroxyaniline, deionized water, epichlorohydrin, potassium hydroxide solution and tetrabutylammonium bromide in step one is 1-2kg:2-3kg:5-6L:1-2L:500-600mL:300-400g.

[0011] Further, the mass ratio of fluorinated modified PVC resin, epoxy composite bentonite powder, methyl tin stabilizer and zinc stearate in step two is 90-100:10-15:1-3:2-3.

[0012] Further, the sulfonated composite bentonite powder is prepared by the following steps:

[0013] Step 1: Tetra butyl titanate, 50-60 wt% ethanol solution and acetic acid solution with a concentration of 3-4 mol / L were added to a reaction kettle, stirred at 60-70 °C and 500-600 r / min for 40-60 min, then nitrogen-doped bentonite powder was added, and stirring was continued for 24-26 h. The filter cake was washed with anhydrous ethanol for 2-3 times, vacuum dried, transferred to a muffle furnace, heated to 350-370 °C, and calcined for 1-2 h under the protection of air. Then, it was heated to 600-650 °C at a rate of 5-6 °C / min under the protection of argon, and kept for 2-3 h. After natural cooling, nitrogen-doped composite bentonite powder was obtained.

[0014] Step 2: Nitrogen-doped composite bentonite powder, 10-15% sulfuric acid and 8-13% nitric acid were added to a reaction kettle, stirred at 60-80 °C and 500-600 r / min for 30-40 min, and then filtered. The filter cake was washed with deionized water until the pH value of the last washing liquid was neutral. After vacuum drying, acidified composite bentonite powder was obtained.

[0015] Step 3: The acidified composite bentonite powder was transferred to a mixed solution of 3-mercaptopropyl trimethoxysilane and ethanol, and stirred at 60-80 °C and 500-600 r / min for 30-40 min. The filter cake was washed with deionized water for 2-3 times, and vacuum dried at 60-80 °C for 1-2 h to obtain mercapto-modified composite bentonite powder.

[0016] Step 4: The mercapto-modified composite bentonite powder was placed in a 20-30 wt% hydrogen peroxide solution, and 0.5-0.6 M sodium hydroxide solution was added to adjust the pH value to 9-10. The filter cake was washed with deionized water and ethanol for 2-3 times, and vacuum dried at 60-80 °C for 1-2 h to obtain sulfonated composite bentonite powder.

[0017] Further, the amount ratio of tetra butyl titanate, ethanol, acetic acid and nitrogen-doped bentonite powder was 3-4 kg: 4-5 L: 500-600 mL: 2-3 kg.

[0018] Further, the amount ratio of nitrogen-doped composite bentonite powder, sulfuric acid and nitric acid was 2-3 kg: 2-3 L: 800-1000 mL.

[0019] Further, the amount ratio of acidified composite bentonite powder, 3-mercaptopropyl trimethoxysilane and ethanol was 1-2 kg: 800-900 mL: 4-5 L.

[0020] Further, the amount ratio of mercapto-modified composite bentonite powder and hydrogen peroxide was 1-2 kg: 2-3 L.

[0021] Further, the fluorinated modified PVC resin was prepared by the following steps:

[0022] The perfluorooctyl ethyl acrylate, 4-hydroxybutyl vinyl ether, deionized water and anhydrous ethanol are added into a reaction kettle, stirred at 57-65 DEG C and 500-600r / min for 1-2h, 1,4-dioxane, peroxide di(2-ethylhexyl) dicarbonate as an initiator and peroxide dilauryl are added into the reaction kettle, then chloroethylene is added into the reaction kettle under nitrogen protection, stirred at 57-65 DEG C and 500-600r / min for 4-5h, a methanol solution with a mass concentration of 20-30% is added into the reaction kettle drop by drop, after the dropwise addition is completed, standing for 24-26h, filtration, the filter cake is washed with anhydrous methanol for 2-3 times, vacuum drying at 60-80 DEG C for 1-2h, to obtain the fluorinated modified PVC resin.

[0023] Further, the use amount ratio of perfluorooctyl ethyl acrylate, 4-hydroxybutyl vinyl ether, deionized water, anhydrous ethanol, 1,4-dioxane, peroxide di(2-ethylhexyl) dicarbonate, peroxide dilauryl, chloroethylene and methanol is 500-600mL:800-900g:2-3L:2-3L:4-5L:800-900g:500-600g:7-8kg:8-9L.

[0024] The beneficial effects of the present application are:

[0025] 1. The anti-permeation PVC drawing film prepared by the present application has good weather resistance, oxidation resistance and anti-permeability, and can be used outdoors for a long time under strong sunlight, rain and other harsh environments; the nitrogen-doped bentonite powder is compounded with titanium dioxide, the bentonite can improve the rheological property of the resin, thereby improving the processing performance of the resin, by introducing nitrogen atoms into the crystal lattice or surface of the bentonite, the charge state of the bentonite can be significantly affected, the compatibility of the bentonite and the resin matrix is improved, at the same time, without adding p-hydroxybenzoic acid as a compatibilizer, the processing performance is also good, avoiding the decomposition of the compatibilizer at high temperature and causing the processing performance of the product to decrease.

[0026] The fluorinated modified PVC resin of the present application, after hydrolysis of perfluorooctyl ethyl acrylate, the hydroxyl group of 4-hydroxybutyl vinyl ether is combined under hydrothermal conditions, grafted in the PVC resin polymer chain, the fluorine atom has strong electronegativity and chemical stability, so that the PVC drawing film has good barrier property, thereby preventing water permeation.

[0027] 2. The epoxy composite bentonite powder of the present application introduces phenolic hydroxyl groups into the epoxy composite bentonite powder by reacting the amine group on the hydroxyaniline with the sulfonic acid group on the surface of the sulfonated composite bentonite powder. The H proton in the phenolic hydroxyl group is easily taken away by free radicals, preventing the chain reaction of free radicals, while forming oxygen free radicals, which can react with other free radicals, effectively improving the oxidation resistance of the stretched PVC film and slowing down the aging of the stretched PVC film. Compared with directly adding antioxidants or anti-aging agents, the anti-aging components in the PVC stretched film produced by this production process do not migrate, and the anti-aging effect is more durable.

[0028] 3. The surface of the bentonite is doped with nitrogen, which introduces nitrogen elements into the crystal lattice of titanium dioxide, improves the spectral absorption range and light absorption capacity, and further improves the reflection and scattering of ultraviolet rays, further reducing the aging rate of the PVC stretched film. Unlike traditional direct addition of antioxidants, it effectively avoids migration in the resin matrix, thereby reducing the service life, stability and safety of the product; the epoxy bentonite molecule contains an epoxy group, which can capture the free radicals Cl - separated during the PVC degradation process, thereby terminating the free radical reaction of PVC degradation, slowing down the degradation rate, and improving the stability of the PVC stretched film. This stabilizing effect enables the PVC stretched film to maintain better performance during use and prolong the service life. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0030] Embodiment 1: A production process for a permeation-resistant PVC stretched film, comprising the following steps:

[0031] S1: 500 mL of perfluoro-octyl ethyl acrylate, 800 g of 4-hydroxybutyl vinyl ether, 2 L of deionized water and 2 L of anhydrous ethanol are added to a reaction kettle, stirred at 57°C and 500 r / min for 1 h, 4 L of 1,4-dioxane, 800 g of peroxide di(2-ethylhexyl) as an initiator and 500 g of peroxide dilauryl are added to the reaction kettle, and then 7 kg of chloroethylene is added to the reaction kettle under nitrogen protection, stirred at 57°C and 500 r / min for 4 h. After the reaction is terminated, 8 L of methanol solution with a mass concentration of 20% is gradually added to the reaction kettle, and after the addition is completed, it is left to stand for 24 h, filtered, the filter cake is washed with anhydrous methanol for 2 times, and vacuum dried at 60°C for 1 h to obtain a fluorinated modified PVC resin.

[0032] After the hydrolysis of perfluorooctyl ethyl acrylate, the hydroxyl group of 4-hydroxybutyl vinyl ether is combined under hydrothermal conditions to graft into the polymerization chain of PVC resin, and a fluorinated modified PVC resin is obtained.

[0033] S2: 4 kg of bentonite powder with a particle size of 2-3 μm, 1 kg of urea and 8 L of anhydrous ethanol were added to the reaction kettle, stirred at 50°C and 400 r / min for 4 h, filtered, the filter cake was washed with deionized water for 2 times, transferred to a muffle furnace, heated to 500°C, kept for 4 h, and naturally cooled to obtain nitrogen-doped bentonite powder.

[0034] Nitrogen doping can significantly affect the charge state, surface polarity and functional group types of bentonite by introducing nitrogen atoms into the crystal lattice or surface of bentonite, and affect the particle morphology and particle size distribution, which together act on the interaction interface between bentonite and resin matrix, and can improve the compatibility between bentonite and resin matrix.

[0035] S3: 3 kg of tetrabutyl titanate, 4 L of 50% ethanol solution and 500 mL of 3 mol / L acetic acid solution were added to the reaction kettle, stirred at 60°C and 500 r / min for 40 min, then 2 kg of nitrogen-doped bentonite powder was added, and the stirring was continued for 24 h, then the filter cake was filtered, washed with anhydrous ethanol for 2 times, vacuum dried at 60°C for 1 h, transferred to a muffle furnace, heated to 350°C, and calcined for 1 h under the protection of air, then heated to 600°C at 5°C / min under the protection of argon, kept for 2 h, and naturally cooled to obtain nitrogen-doped composite bentonite powder.

[0036] Depositing titanium dioxide on the surface of nitrogen-doped bentonite powder and calcining can promote the crystal type transition of TiO2 from unstable crystal type to stable type.

[0037] S4: 2 kg of nitrogen-doped composite bentonite powder, 2 L of 10% sulfuric acid and 800 mL of 8% nitric acid were added to the reaction kettle, stirred at 60°C and 500 r / min for 30 min, filtered, the filter cake was washed with deionized water until the pH value of the last washing liquid was neutral, and vacuum dried to obtain acidified composite bentonite powder; 1 kg of acidified composite bentonite powder was transferred to a mixed solution of 800 mL of 3-mercaptopropyl trimethoxysilane and 4 L of ethanol, stirred at 60°C and 500 r / min for 30 min, filtered, the filter cake was washed with deionized water for 2 times, and vacuum dried at 60°C for 1 h to obtain mercapto-modified composite bentonite powder; 1 kg of mercapto-modified composite bentonite powder was placed in 2 L of 20 wt% hydrogen peroxide solution, 0.5 M sodium hydroxide solution was added to adjust the pH value to 9, filtered, the filter cake was washed with deionized water and ethanol for 2 times, and vacuum dried at 60°C for 1 h to obtain sulfonated composite bentonite powder.

[0038] After the nitrogen-doped composite bentonite powder is acidized, it is treated in a 3-mercaptopropyl trimethoxysilane solution, the mercapto groups are grafted on the surface of the nitrogen-doped bentonite, and then the mercapto groups are oxidized by hydrogen peroxide to obtain sulfonic acid groups.

[0039] S5: 1 kg of sulfonated composite bentonite powder, 2 kg of p-hydroxyaniline, and 5 L of deionized water are added to a reaction kettle, stirred at 50°C and 400 r / min for 1 h, 1 L of epichlorohydrin is added to the reaction kettle, stirred at 50°C and 400 r / min for 30 min, 500 mL of 50 wt% potassium hydroxide solution and 300 g of tetrabutylammonium bromide are added to the reaction kettle, stirred at 50°C and 400 r / min for 24 h, filtered, the filter cake is washed with deionized water and anhydrous ethanol for 2 times respectively, and vacuum dried at 60°C for 1 h to obtain an epoxy composite bentonite powder.

[0040] The phenolic hydroxyl groups are introduced into the epoxy composite bentonite powder by reacting the amine groups on the p-hydroxyaniline with the sulfonic acid groups on the surface of the sulfonated composite bentonite powder. The H protons in the phenolic hydroxyl groups are easily taken away by free radicals, which prevents the chain reaction of free radicals, and at the same time forms oxygen free radicals, which can react with other free radicals, thereby slowing down the aging of the stretched film and effectively improving the oxidation resistance of the stretched film. The epoxy-modified bentonite powder is obtained by reacting epichlorohydrin with the hydroxyl groups on the surface of the sulfonated composite bentonite powder.

[0041] S6: Fluorinated modified PVC resin, epoxy composite bentonite powder, methyl tin stabilizer and zinc stearate are uniformly mixed in a mass ratio of 90:10:1:2, then plasticized and mixed by a double roller mill at 180°C for 10 min, the obtained sheet is formed by a four-roll calendering device at 180°C, and a non-fluorine waterproof and oil-proof agent is sprayed on the formed sheet at a dosage of 200 mL / m 2 , dried at 50°C for 50 min, cooled and rolled up to obtain a non-permeable PVC stretched film.

[0042] Example 2: A production process of a non-permeable PVC stretched film, by the following steps:

[0043] S1: 550 mL of perfluoro-octyl ethyl acrylate, 850 g of 4-hydroxybutyl vinyl ether, 2.3 L of deionized water and 2.3 L of anhydrous ethanol were added to the reaction kettle, stirred at 60℃ and 550 r / min for 1.2 h, 4.5 L of 1,4-dioxane, 850 g of di(2-ethylhexyl) peroxydicarbonate as an initiator and 550 g of dilauroyl peroxide were added to the reaction kettle, 7.8 kg of chloroethylene was added to the reaction kettle under the protection of nitrogen, stirred at 60℃ and 550 r / min for 4.5 h, after the reaction was terminated, 8.9 L of methanol solution with a mass concentration of 25% was added to the reaction kettle drop by drop, after the dropwise addition was completed, it was placed for 25 h, filtered, the filter cake was washed with anhydrous methanol for 2 times, vacuum dried at 70℃ for 1.2 h, and a fluorinated modified PVC resin was obtained.

[0044] S2: 4.5 kg of bentonite powder with a particle size of 2-3 μm, 1.2 kg of urea and 8.9 L of anhydrous ethanol were added to the reaction kettle, stirred at 55℃ and 450 r / min for 4.5 h, filtered, the filter cake was washed with deionized water for 2 times, transferred to a muffle furnace, heated to 530℃, kept for 5 h, and naturally cooled to obtain a nitrogen-doped bentonite powder.

[0045] S3: 3.4 kg of tetrabutyl titanate, 4.5 L of an ethanol solution with a mass fraction of 55% and 550 mL of an acetic acid solution with a concentration of 3 mol / L were added to the reaction kettle, stirred at 65℃ and 550 r / min for 50 min, then 2.3 kg of nitrogen-doped bentonite powder was added, and the stirring was continued for 25 h, filtered, the filter cake was washed with anhydrous ethanol for 2 times, vacuum dried at 70℃ for 1.2 h, transferred to a muffle furnace, heated to 360℃, and air was introduced for calcination for 1.2 h, heated to 630℃ at 5℃ / min under the protection of argon, kept for 2.3 h, and naturally cooled to obtain a nitrogen-doped composite bentonite powder.

[0046] S4: 2.3 kg of nitrogen-doped composite bentonite powder, 2.3 L of 13% by mass sulfuric acid, and 900 mL of 10% by mass nitric acid were added to a reaction kettle, stirred at 70°C and 550 r / min for 35 min, filtered, the filter cake was washed with deionized water until the last washing liquid was neutral, and vacuum dried to obtain an acidified composite bentonite powder; 1.2 kg of the acidified composite bentonite powder was transferred to a mixed solution of 850 mL of 3-mercaptopropyltrimethoxysilane and 4.5 L of ethanol, stirred at 70°C and 550 r / min for 35 min, filtered, the filter cake was washed with deionized water twice, and vacuum dried at 70°C for 1.2 h to obtain a mercapto-modified composite bentonite powder; 1.2 kg of the mercapto-modified composite bentonite powder was placed in 2.3 L of 25 wt% hydrogen peroxide solution, 0.55 M sodium hydroxide solution was added to a pH value of 9, filtered, the filter cake was washed with deionized water and ethanol twice, and vacuum dried at 70°C for 1.2 h to obtain a sulfonated composite bentonite powder.

[0047] S5: 1.2 kg of the sulfonated composite bentonite powder, 2.3 kg of p-hydroxyaniline, and 5.6 L of deionized water were added to a reaction kettle, stirred at 55°C and 450 r / min for 1.2 h, 1.2 L of epichlorohydrin was added to the reaction kettle, stirred at 55°C and 450 r / min for 40 min, 550 mL of 55 wt% potassium hydroxide solution and 350 g of tetrabutylammonium bromide were added to the reaction kettle, stirred at 55°C and 450 r / min for 25 h, filtered, the filter cake was washed with deionized water and anhydrous ethanol for 3 times respectively, and vacuum dried at 70°C for 2 h to obtain an epoxy composite bentonite powder.

[0048] S6: The fluorine-free waterproof and oil-proof agent was sprayed on the formed sheet according to the amount of 250 mL / m2, dried at 55°C for 70 min, cooled and rolled up to obtain a waterproof and oil-proof PVC film. 2

[0049] Example 3: A production process of a waterproof and oil-proof PVC film, by the following steps:

[0050] ​S1: 600 mL of perfluorooctyl ethyl acrylate, 900 g of 4-hydroxybutyl vinyl ether, 3 L of deionized water and 3 L of anhydrous ethanol were added to the reaction kettle, stirred at 65°C and 600 r / min for 2 h, 5 L of 1,4-dioxane, 900 g of di(2-ethylhexyl)peroxydicarbonate as an initiator and 600 g of dilauroyl peroxide were added to the reaction kettle, 8 kg of chloroethylene was added to the reaction kettle under the protection of nitrogen, stirred at 65°C and 600 r / min for 5 h, after the reaction was terminated, 9 L of methanol solution with a mass concentration of 30% was added to the reaction kettle drop by drop, after the dropwise addition was completed, it was placed for 26 h, filtration, the filter cake was washed with anhydrous methanol for 3 times, vacuum dried at 80°C for 2 h, and fluorinated modified PVC resin was obtained.

[0051] S2: 5 kg of bentonite powder with a particle size of 2-3 μm, 2 kg of urea and 9 L of anhydrous ethanol were added to the reaction kettle, stirred at 60°C and 500 r / min for 5 h, filtration, the filter cake was washed with deionized water for 3 times, transferred to a muffle furnace, heated to 550°C, kept for 6 h, and naturally cooled to obtain nitrogen-doped bentonite powder.

[0052] S3: 4 kg of tetrabutyl titanate, 5 L of 60% ethanol solution and 600 mL of 4 mol / L acetic acid solution were added to the reaction kettle, stirred at 70°C and 600 r / min for 60 min, then 3 kg of nitrogen-doped bentonite powder was added, and stirring was continued for 26 h, filtration, the filter cake was washed with anhydrous ethanol for 3 times, vacuum dried at 80°C for 2 h, transferred to a muffle furnace, heated to 370°C, and air was introduced, calcined for 2 h, heated to 650°C at 6°C / min under the protection of argon, kept for 3 h, and naturally cooled to obtain nitrogen-doped composite bentonite powder.

[0053] S4: 3 kg of nitrogen-doped composite bentonite powder, 3 L of 15% sulfuric acid and 1000 mL of 13% nitric acid were added to the reaction kettle, stirred at 80°C and 600 r / min for 40 min, filtration, the filter cake was washed with deionized water until the pH value of the last washing liquid was neutral, and vacuum dried to obtain acidified composite bentonite powder; 2 kg of acidified composite bentonite powder was transferred to a mixed solution of 900 mL of 3-mercaptopropyl trimethoxysilane and 5 L of ethanol, stirred at 80°C and 600 r / min for 40 min, filtration, the filter cake was washed with deionized water for 3 times, and vacuum dried at 80°C for 2 h to obtain mercapto-modified composite bentonite powder; 2 kg of mercapto-modified composite bentonite powder was placed in 3 L of 30 wt% hydrogen peroxide solution, 0.6 M sodium hydroxide solution was added to the solution until the pH value was 10, filtration, the filter cake was washed with deionized water and ethanol for 3 times, and vacuum dried at 80°C for 2 h to obtain sulfonated composite bentonite powder.

[0054] S5: 2 kg of sulfonated composite bentonite powder, 3 kg of p-hydroxyaniline, and 6 L of deionized water were added to a reaction kettle, stirred at 60 °C and 500 r / min for 2 h, 2 L of epichlorohydrin was added to the reaction kettle, stirred at 560 °C and 500 r / min for 50 min, 600 mL of 60 wt% potassium hydroxide solution and 400 g of tetrabutylammonium bromide were added to the reaction kettle, stirred at 60 °C and 500 r / min for 26 h, filtered, the filter cake was washed with deionized water and anhydrous ethanol for 3 times respectively, vacuum dried at 80 °C for 2 h, to obtain an epoxy composite bentonite powder.

[0055] S6: The fluorinated modified PVC resin, the epoxy composite bentonite powder, the methyl tin stabilizer and the zinc stearate were mixed uniformly according to the mass ratio of 100:15:3:3, then a double roller open mill was used to mix and plasticize at 190 °C for 12 min, the obtained sheet was formed by a four-roll calendering device at 190 °C, a fluorine-free waterproof and oil-proof agent was sprayed on the formed sheet according to the dosage of 300 mL / m2, dried at 60 °C for 80 min, cooled and rolled up, to obtain a waterproof PVC calendering film. 2

[0056] Comparative Example 1: On the basis of Example 3, a special titanium dioxide for PVC calendering film was prepared according to the preparation method with publication number CN107383421A, the epoxy composite bentonite powder in step S6 was replaced, and the remaining steps remained unchanged, to obtain a waterproof PVC calendering film.

[0057] Comparative Example 2: On the basis of Example 3, the nitrogen-doped bentonite powder in step S3 was replaced by the bentonite powder in step S3, and the remaining steps remained unchanged, to obtain a waterproof PVC calendering film.

[0058] Comparative Example 3: On the basis of Example 3, the epoxy composite bentonite powder in step S6 was replaced by the sulfonated composite bentonite powder in step S4, and the remaining steps remained unchanged, to obtain a waterproof PVC calendering film.

[0059] Comparative Example 4: On the basis of Example 3, the nitrogen-doped composite bentonite powder in step S4 was replaced by the nitrogen-doped bentonite powder in step S2, and the remaining steps remained unchanged, to obtain a waterproof PVC calendering film.

[0060] Comparative Example 5: On the basis of Example 3, the fluorinated modified PVC resin in step S1 was replaced by a commercially available PVC resin, and the remaining steps remained unchanged, to obtain a waterproof PVC calendering film.

[0061] In the examples and comparative examples:

[0062] Perfluoroethyloctyl acrylate was purchased from Shandong Lubang Chemical Co., Ltd.​

[0063] Hydroxybutyl vinyl ether, 1,4-dioxane, di(2-ethylhexyl) peroxydicarbonate, dilauroyl peroxide, titanium tetrachloride and p-hydroxyaniline were purchased from Sigma-Aldrich.

[0064] The fluorine-free waterproof and oil-repellent agent was purchased from Shanghai Xiangjin Chemical Co., Ltd.

[0065] The properties of the impermeable PVC calendering film prepared in Example 1-Example 3 and Comparative Example 1-Comparative Example 3 were tested, and the results are shown in Table 1:

[0066] 1. Anti-yellowing test: The PVC calendering film was placed in an ultraviolet light aging test box for 20 days of testing, and the three stimulus values X, Y and Z of different samples before and after aging were tested by referring to the GB2409 standard using a YI-48A whiteness colorimeter. The yellow index of the film sample before and after aging was calculated by the following formula: YI = [100 x (1.28X-1.06Z)] / Y, (ΔYIn = YIn-YI0 formula, ΔYIn is the change amount of the yellow index of the sample after aging for n days; YI0 and YIn are the yellow index values of the film sample before and after aging for n days, respectively).

[0067] 2. Mechanical property test: The test was carried out in accordance with the standard of GB / T1040-2006.

[0068] 3. Ultraviolet transmittance: The test was carried out using an ultraviolet visible spectrophotometer, and the average transmittance at a wavelength of 315-380 nm (UV-A) was used to represent the ultraviolet transmittance.

[0069] Table 1 Properties test table of impermeable PVC calendering film

[0070] Item Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Yellowness Index (YI) 0.64 0.51 0.44 3.1 2.2 2.1 3.6 1.7 Tensile Strength (Mpa) 23.2 23.8 24.2 21.5 21.2 20.2 23.1 25.1 Elongation at Break (%) 350 352 356 334 332 353 335 363 UV-A Transmittance (%) 5.4 5.2 5.1 6.2 7.0 7.0 8.1 5.4

[0071] As can be seen from Table 1, the tensile strength, elongation at break and transmittance of the impermeable PVC calendering film prepared in Example 1-Example 3 are significantly better than those of the comparative examples, which shows that the PVC calendering film of the present application has good tensile strength, impact resistance and anti-aging properties.

[0072] In Comparative Example 1, the special titanium dioxide for PVC calendering film was prepared according to the preparation method with publication number CN107383421A. The p-hydroxybenzoic acid has good dispersion effect on the titanium dioxide, and promotes the compatibility of the modified titanium dioxide with the film resin. However, the p-hydroxybenzoic acid decomposes at a temperature of 190°C after calendering molding, resulting in poor performance test and decreased processing performance of the product.

[0073] In the comparative example 2, the nitrogen-doped bentonite powder is replaced by bentonite powder. Nitrogen doping changes the surface properties of bentonite, improves the compatibility of the resin matrix, helps the uniform dispersion of bentonite in the resin, reduces the occurrence of agglomeration, and has a positive effect on the flowability of the resin. The rheological properties of the resin are improved, thereby improving the processing performance of the resin, and the performance tests of tensile strength and elongation at break decrease. Nitrogen can affect the crystal structure of titanium dioxide, improve the spectral absorption range and light absorption capacity, and further improve the reflection and scattering of ultraviolet light, thereby further reducing the aging rate of the PVC calendering film. Therefore, the ultraviolet transmittance is slightly affected after losing nitrogen doping.

[0074] In the comparative example 3, the epoxy composite bentonite powder is replaced by sulfonated composite bentonite powder. The phenolic hydroxyl group is introduced into the epoxy composite bentonite powder. The H proton in the phenolic hydroxyl group is easily taken away by free radicals, which prevents the chain reaction of free radicals and forms oxygen free radicals at the same time. Oxygen free radicals can react with other free radicals, thereby slowing down the aging of the calendering film and effectively improving the oxidation resistance of the calendering film. The epoxy bentonite molecule contains an epoxy group, which can capture free radicals Cl - released during the degradation of PVC, thereby terminating the free radical reaction of PVC degradation and further slowing down the degradation rate, thereby improving the stability of the PVC calendering film.

[0075] In the comparative example 4, the nitrogen-doped composite bentonite powder is replaced by nitrogen-doped bentonite powder. When ultraviolet light irradiates the surface of titanium dioxide, electrons in titanium dioxide are excited. These excited electrons will jump to a higher energy level, thereby absorbing ultraviolet light. Titanium dioxide can also effectively scatter ultraviolet light, thereby reducing the direct irradiation intensity on the PVC calendering film and further effectively improving the oxidation resistance of the calendering film, thereby avoiding the aging of the PVC calendering film caused by long-term ultraviolet irradiation. Therefore, the ultraviolet transmittance performance test is the worst after losing titanium dioxide.

[0076] In the comparative example 5, the mechanical properties of the impermeable PVC calendering film are slightly improved, and the yellowing resistance is improved. Fluorine atoms have strong electronegativity and chemical stability. The molecular chain structure of fluorinated PVC resin is tight, which can improve the yellowing resistance of the PVC calendering film, but will cause the mechanical properties to decrease.

[0077] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting; it is not intended to exclude myriad other embodiments of the present application that other inventors can develop based on the same general inventive concepts embodied by the described embodiments. That is, although the present application is described in terms of particular embodiments and illustrative figures, it should be apparent that the scope of the present application is not limited to these specific embodiments.

[0078] While the embodiments of the application have been shown and described herein, it will be understood by those of ordinary skill in the art that various changes, modifications, alternatives, and variations can be made to the embodiments without departing from the spirit and scope of the application, which is defined by the appended claims and their equivalents.

Claims

1. A production process for an anti-permeability PVC calendered film, characterized in that, Includes the following steps: Step 1: Add sulfonated composite bentonite powder, p-hydroxyaniline and deionized water to a reaction vessel, stir at 50-60℃ and 400-500 r / min for 1-2 h, then add epichlorohydrin and stir for 30-50 min, then add 50-60 wt% potassium hydroxide solution and tetrabutylammonium bromide to the reaction vessel, continue stirring for 24-26 h, filter, wash the filter cake 2-3 times with deionized water and ethanol, and vacuum dry to obtain epoxy composite bentonite powder; Step 2: Mix the fluorinated modified PVC resin, epoxy composite bentonite powder, methyl tin stabilizer, and zinc stearate evenly, then use a two-roll mill to mix and plasticize at 180-190℃ for 10-12 minutes. Calender the resulting sheet using a four-roll calender at 180-190℃. Apply the fluorine-free waterproof and oil-repellent agent at a ratio of 200-300 mL / m². 2 The amount of the coating is sprayed onto the formed sheet, dried at 50-60℃ for 50-80 minutes, cooled and rolled up to obtain an impermeable PVC calendered film. The sulfonated composite bentonite powder in step one is prepared through the following steps: Acidified composite bentonite powder was transferred to a mixed solution of 3-mercaptopropyltrimethoxysilane and ethanol, stirred at 60-80℃ and 500-600 r / min for 30-40 min, filtered, and the filter cake was washed 2-3 times with deionized water and vacuum dried to obtain mercapto-modified composite bentonite powder; the mercapto-modified composite bentonite powder was placed in a 20-30 wt% hydrogen peroxide solution, and a 0.5-0.6 M sodium hydroxide solution was added to adjust the pH to 9-10, filtered, and the filter cake was washed 2-3 times with deionized water and ethanol and vacuum dried to obtain sulfonated composite bentonite powder; The acidified composite bentonite powder is prepared by the following steps: Nitrogen-doped composite bentonite powder, 10-15 wt% sulfuric acid and 8-13 wt% nitric acid are added to a reaction vessel and stirred at 60-70℃ and 500-600 r / min for 30-40 min. The mixture is filtered, and the filter cake is washed with deionized water until the pH of the final washing solution is neutral. The mixture is then vacuum dried to obtain acidified composite bentonite powder. The nitrogen-doped composite bentonite powder is prepared by the following steps: Tetrabutyl titanate, 50-60wt% ethanol solution, and 3-4mol / L acetic acid solution were added to a reaction vessel and stirred at 60-70℃ and 500-600r / min for 40-60min. Then, nitrogen-doped bentonite powder was added, and stirring was continued for 24-26h. The mixture was filtered, and the filter cake was washed 2-3 times with anhydrous ethanol, vacuum dried, transferred to a muffle furnace, heated to 350-370℃, and calcined for 1-2h with air introduced. Under argon protection, the mixture was heated to 600-650℃ at 5-6℃ / min and held for 2-3h. After natural cooling, nitrogen-doped composite bentonite powder was obtained.

2. The production process of an anti-permeability PVC calendered film according to claim 1, characterized in that, The ratio of sulfonated composite bentonite powder, p-hydroxyaniline, deionized water, epichlorohydrin, potassium hydroxide solution and tetrabutylammonium bromide used in step one is 1-2 kg: 2-3 kg: 5-6 L: 1-2 L: 500-600 mL: 300-400 g.

3. The production process of an anti-permeability PVC calendered film according to claim 1, characterized in that, In step two, the mass ratio of fluorinated modified PVC resin, epoxy composite bentonite powder, methyl tin stabilizer, and zinc stearate is 90-100:10-15:1-3:2-3.

4. The production process of an anti-permeability PVC calendered film according to claim 1, characterized in that, The ratio of acidified composite bentonite powder, 3-mercaptopropyltrimethoxysilane and ethanol is 1-2 kg: 800-900 mL: 4-5 L; the ratio of mercapto-modified composite bentonite powder and hydrogen peroxide is 1-2 kg: 2-3 L.

5. The production process of an anti-permeability PVC calendered film according to claim 1, characterized in that, The ratio of nitrogen-doped composite bentonite powder, sulfuric acid, and nitric acid used is 2-3 kg: 2-3 L: 800-1000 mL.

6. The production process of an anti-permeability PVC calendered film according to claim 1, characterized in that, The ratio of tetrabutyl titanate, ethanol, acetic acid and nitrogen-doped bentonite powder is 3-4 kg: 4-5 L: 500-600 mL: 2-3 kg.

7. The production process of an anti-permeability PVC calendered film according to claim 6, characterized in that, The nitrogen-doped bentonite powder is prepared by the following steps: Bentonite powder with a particle size of 2-3 μm, urea and anhydrous ethanol are added to a reaction vessel and stirred at 50-60℃ and 400-500 r / min for 4-5 h. After filtration, the filter cake is washed 2-3 times with deionized water, transferred to a muffle furnace, heated to 500-550℃, held for 4-6 h, and cooled naturally to obtain nitrogen-doped bentonite powder. The ratio of bentonite powder, urea and anhydrous ethanol is 4-5 kg: 1-2 kg: 8-9 L.

8. The production process of an anti-permeability PVC calendered film according to claim 1, characterized in that, The fluorinated modified PVC resin mentioned in step two is prepared through the following steps: Perfluorooctyl ethyl acrylate, 4-hydroxybutyl vinyl ether, deionized water and anhydrous ethanol were added to a reaction vessel and stirred at 57-65℃ and 500-600 r / min for 1-2 h. 1,4-Dioxane, di(2-ethylhexyl) peroxydicarbonate and dilauryl peroxide were added to the reaction vessel. Under nitrogen protection, vinyl chloride was added to the reaction vessel and stirred at 57-65℃ and 500-600 r / min for 4-5 h. A 20-30 wt% methanol solution was added dropwise to the reaction vessel and allowed to stand for 24-26 h. The mixture was filtered, and the filter cake was washed 2-3 times with anhydrous methanol and dried under vacuum to obtain fluorinated modified PVC resin.

9. The production process of an anti-permeability PVC calendered film according to claim 8, characterized in that, The ratio of perfluorooctyl ethyl acrylate, 4-hydroxybutyl vinyl ether, deionized water, anhydrous ethanol, 1,4-dioxane, di(2-ethylhexyl) peroxydicarbonate, dilauroyl peroxide, vinyl chloride, and methanol is 500-600 mL: 800-900 g: 2-3 L: 2-3 L: 4-5 L: 800-900 g: 500-600 g: 7-8 kg: 8-9 L.

10. A translucent PVC calendered membrane, characterized in that, It is produced by the production process described in any one of claims 1-9.