High-toughness weather-resistant high-temperature-resistant chlorinated polyvinyl chloride and production method thereof

Abstract

The invention discloses high-toughness weather-resistant high-temperature-resistant chlorinated polyvinyl chloride and a production method thereof, and belongs to the technical field of chlorinated polyvinyl chloride, the production method comprises pretreatment, reaction and post-treatment; the reaction comprises the following steps: sealing a reaction device, replacing air in the reaction device with nitrogen, adding pretreated polyvinyl chloride, Tween 80, styrene, 1, 2-dichloroethane and deionized water into the reaction device, stirring at 75-80 DEG C, adding azodiisobutyronitrile, fumed silica, a polyvinyl alcohol aqueous solution and methacrylic acid, then irradiating with ultraviolet light, and reacting at the temperature of 75-80 DEG C, so as to obtain the polyvinyl chloride resin. The preparation method comprises the following steps of: adding sodium hydroxide into a reaction kettle, simultaneously introducing chlorine gas, stirring, adding lime milk to adjust the pH value to 6-6.5, heating to 85-90 DEG C, adding azodiisobutyronitrile, 2-dodecyl acrylate and vinyl stearate, and stirring; the chlorinated polyvinyl chloride prepared by the invention has the advantages of high toughness, good weather resistance and high temperature resistance, and also has excellent mechanical strength, machinability and appearance.

Description

Technical Field

[0001] The present invention relates to the technical field of chlorinated polyvinyl chloride, and particularly relates to a high-toughness, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride and a production method thereof. Background Art

[0002] Chlorinated polyvinyl chloride is a high-performance polymer material obtained by chlorination modification of polyvinyl chloride, and is a white or light yellow loose granule or powder. The chlorine content of chlorinated polyvinyl chloride has been significantly increased compared with that of polyvinyl chloride, from 56.7% to 60 - 68%, and can reach up to 73.2% at most. With the increase of the chlorine content, the irregularity of the molecules increases, the crystallinity decreases, and the polarity of the molecular chain is enhanced, enhancing the acid resistance, alkali resistance and oxidation resistance of chlorinated polyvinyl chloride, and also improving the high-temperature stability of chlorinated polyvinyl chloride. The Vicat softening temperature of chlorinated polyvinyl chloride can be increased from 72 - 82°C of polyvinyl chloride to 90 - 125°C, the maximum use temperature can reach 110°C, and the long-term stable use temperature can reach 95°C. At the same time, chlorinated polyvinyl chloride also has excellent low-temperature stability and can be used in a low-temperature environment of -40°C. In addition, chlorinated polyvinyl chloride also has excellent weather resistance, flame retardancy and mechanical strength. Due to the above excellent properties of chlorinated polyvinyl chloride, chlorinated polyvinyl chloride has been widely used in the fields of chemical industry, building materials, aviation, automobiles, electrical appliances, textiles, etc.

[0003] However, in the processing and use of chlorinated polyvinyl chloride, there are the following problems: First, the melt viscosity of chlorinated polyvinyl chloride is much higher than that of polyvinyl chloride, resulting in great processing difficulty and poor processability of chlorinated polyvinyl chloride; Second, the melting temperature of chlorinated polyvinyl chloride is close to its thermal decomposition temperature, resulting in a narrow processing temperature range of chlorinated polyvinyl chloride and being very sensitive to processing conditions, and strict temperature control is required. If the processing temperature is too high, degradation is likely to occur during processing, generating hydrogen chloride gas, and the hydrogen chloride gas further catalyzes and accelerates the degradation of chlorinated polyvinyl chloride, forming conjugated double bonds, ultimately affecting the color and mechanical strength of chlorinated polyvinyl chloride, and further resulting in poor processability of chlorinated polyvinyl chloride; Third, chlorinated polyvinyl chloride is brittle, especially in a low-temperature environment, with great brittleness.

[0004] To address the above problems, the commonly used solution is to physically blend or chemically modify chlorinated polyvinyl chloride. Among them, physical blending modification involves mixing some materials with special properties with chlorinated polyvinyl chloride through physical methods to improve the high-temperature resistance and toughness of chlorinated polyvinyl chloride and reduce its melt viscosity. For example, heat stabilizers, processing aids, and impact modifiers are simultaneously mixed with chlorinated polyvinyl chloride through physical methods. Heat stabilizers mainly include lead salt stabilizers, metal soap stabilizers, and organotin stabilizers. Processing aids are mainly acrylate processing aids (ACR processing aids). Impact modifiers mainly include methyl methacrylate-butadiene-styrene terpolymer (MBS impact modifier), acrylonitrile-butadiene-styrene terpolymer (ABS impact modifier), and chlorinated polyethylene (CPE impact modifier). However, the use effects of the above impact modifiers are generally average, specifically manifested as follows: both the molecular chains of MBS impact modifier and ABS impact modifier contain unsaturated double bonds, resulting in a decrease in the weather resistance of chlorinated polyvinyl chloride, and CPE impact modifier will reduce the high-temperature resistance of chlorinated polyvinyl chloride. In addition, heat stabilizers, processing aids, and impact modifiers all have poor compatibility with chlorinated polyvinyl chloride, resulting in the fact that although they can improve certain properties of chlorinated polyvinyl chloride after being added, they affect other properties of chlorinated polyvinyl chloride. Therefore, it is very difficult to obtain chlorinated polyvinyl chloride with excellent weather resistance, mechanical strength, processability, and high-temperature resistance through existing physical blending modification.

[0005] Chemical modification involves attaching various graft monomers to the side groups or ends of chlorinated polyvinyl chloride, such as lower alkyl acrylates, higher alkyl acrylates, lower alkyl methacrylates, higher alkyl methacrylates, lower alkyl stearates, styrene, etc., to endow chlorinated polyvinyl chloride with different properties and further improve its comprehensive performance. The main chemical modification methods of chlorinated polyvinyl chloride are the post-chlorination grafting method and the in-situ chlorination grafting method. Considering the advantages of simple process and strong environmental protection of the aqueous suspension method, the aqueous suspension method is mainly used in chlorination and grafting. Among them, the post-chlorination grafting method is to chlorinate polyvinyl chloride first to obtain chlorinated polyvinyl chloride, and then use other monomers for grafting to obtain chlorinated polyvinyl chloride. However, during grafting, affected by the number of unstable chlorine on chlorinated polyvinyl chloride, the number of grafting points is small and the grafting points are relatively fixed, resulting in a low grafting rate of the product. Further, the improvement of the comprehensive performance of chlorinated polyvinyl chloride is not significant; the in-situ chlorination grafting method is the most widely used chemical modification method at present. By grafting during the chlorination process, chlorinated polyvinyl chloride is obtained. However, chlorination and grafting are competitive reactions, resulting in a low grafting rate of the product and difficult reaction control, resulting in unstable product quality. In addition, when chlorination is carried out by the aqueous suspension method, the generated hydrogen chloride will make the system acidic. If chlorination and grafting are carried out simultaneously, the graft monomers will hydrolyze under acidic conditions, further affecting the improvement of the performance of chlorinated polyvinyl chloride.

[0006] In view of the problems existing in the above in-situ chlorination grafting method, through retrieval, there are the following three existing solutions: First, in the in-situ chlorination grafting method, by increasing the dosage of each graft monomer, the grafting rate is increased. However, as the dosage of each graft monomer increases, there is a homopolymerization reaction of each graft monomer, and there is a competitive grafting between the homopolymerization product and other graft monomers, resulting in little improvement in the grafting rate of the product. Further, the improvement of the comprehensive performance of chlorinated polyvinyl chloride is not significant; Second, pre-treat polyvinyl chloride, specifically, mix polyvinyl chloride with an alkaline aqueous solution and react at high temperature to remove part of the hydrogen chloride in polyvinyl chloride to form double bonds. The double bonds are easy to become grafting points during grafting, thereby increasing the grafting rate. However, the remaining double bonds will affect the weather resistance and high-temperature resistance of chlorinated polyvinyl chloride and are also easy to form coloring groups, affecting the appearance of chlorinated polyvinyl chloride; Third, first use graft monomers that are not easily hydrolyzed under acidic conditions in the in-situ chlorination grafting method, and then graft graft monomers that are easily hydrolyzed under acidic conditions. However, in the in-situ chlorination grafting method, first, the chlorine radicals generated by chlorine attack the main chain of polyvinyl chloride to generate polyvinyl chloride radicals, and then the polyvinyl chloride radicals combine with the double bonds in the graft monomers. If grafting is carried out alone, there are still the same problems as the post-chlorination grafting method, that is, the problem of low grafting rate. Summary of the Invention

[0007] In view of the deficiencies of the prior art, the present invention provides a highly tough, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride and its production method. The prepared chlorinated polyvinyl chloride has the advantages of high toughness, good weather resistance and high-temperature resistance, and also has excellent mechanical strength, processability and appearance.

[0008] To solve the above technical problems, the technical solutions adopted by the present invention are as follows: A production method of highly tough, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride, comprising: pretreatment, reaction, and post-treatment; For the pretreatment, polyvinyl chloride and zinc oxide are added to a stirring device and stirred at a stirring speed of 50 - 100 rpm for 30 - 40 min at room temperature, then transferred to a microwave oven and heated with medium power microwave for 25 - 30 min to obtain pretreated polyvinyl chloride; In the pretreatment, the mass ratio of polyvinyl chloride to zinc oxide is 200 - 230:6 - 6.2; The polyvinyl chloride is SG-5 type polyvinyl chloride with an average particle size of 120 μm; The average particle size of the zinc oxide is 200 nm; The power of the medium power microwave is 500 W; For the reaction, after sealing the reaction device, the air in the reaction device is replaced with nitrogen. Pretreated polyvinyl chloride, Tween 80, styrene, 1,2-dichloroethane, and deionized water are added to the reaction device and stirred at a stirring speed of 300 - 400 rpm at 75 - 80 °C for 4 - 5 h. The first portion of azobisisobutyronitrile, fumed silica, polyvinyl alcohol aqueous solution, and methacrylic acid are added, and then irradiated with ultraviolet light while chlorine gas is introduced. After the introduction is completed, stirring is continued for 2 - 2.5 h. Lime milk is added to adjust the pH to 6 - 6.5, and the temperature is raised to 85 - 90 °C. The second portion of azobisisobutyronitrile, dodecyl acrylate, and vinyl stearate are added, and stirring is continued for 3 - 3.5 h to obtain a reaction product; In the reaction, the mass ratio of Tween 80, styrene, 1,2-dichloroethane, and deionized water is 24 - 27:7 - 7.5:75 - 80:900 - 950; The mass ratio of the first portion of azobisisobutyronitrile, fumed silica, polyvinyl alcohol aqueous solution, and methacrylic acid is 0.27 - 0.3:5 - 5.3:3.2 - 3.5:7.8 - 8.2; The mass ratio of the second portion of azobisisobutyronitrile, dodecyl acrylate, and vinyl stearate is 0.1 - 0.11:8.5 - 9:4.4 - 4.7; The mass ratio of styrene, methacrylic acid, and dodecyl acrylate is 7 - 7.5:7.8 - 8.2:8.5 - 9; The mass ratio of polyvinyl chloride in the pretreatment to deionized water in the reaction is 200 - 230:900 - 950; The average particle size of the fumed silica is 30 nm; The mass concentration of the polyvinyl alcohol aqueous solution is 5%, and the model of the polyvinyl alcohol is polyvinyl alcohol 1788; The mass concentration of the lime milk is 20%; The power of the ultraviolet light is 500 W, and the wavelength is 210 nm; When introducing chlorine gas, the flow rate of the chlorine gas is 180 - 200 mL / min; The mass ratio of polyvinyl chloride to the total chlorine introduction amount is 1:0.47 - 0.5; For the post-treatment, after filtering the reactants by suction, taking the filter residue, neutralizing the filter residue with an aqueous sodium bicarbonate solution, washing with water, and then drying in vacuum at 60 - 70 °C, high-toughness, weather-resistant, and high-temperature-resistant chlorinated polyvinyl chloride is obtained; The mass concentration of the aqueous sodium bicarbonate solution is 5%.

[0009] A high-toughness, weather-resistant, and high-temperature-resistant chlorinated polyvinyl chloride prepared by the aforementioned preparation method.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) In the production method of the high-toughness, weather-resistant, and high-temperature-resistant chlorinated polyvinyl chloride of the present invention, polyvinyl chloride can form a complex with zinc oxide during microwave heating. After mixing polyvinyl chloride and zinc oxide and performing microwave heating, pretreated polyvinyl chloride is obtained. Zinc oxide can combine with the active chlorine of polyvinyl chloride to fix the active chlorine. Then, the chlorination and grafting are carried out using the in-situ chlorination grafting method. The chlorine radicals in the chlorination can promote the formation of free radicals, thereby promoting grafting. At the same time, the hydrogen chloride generated during chlorination reacts with zinc oxide. Zinc chloride, as a Lewis acid, can play a reverse role, that is, promoting the removal of hydrogen chloride from the complexed active chlorine, thereby gradually releasing grafting points and promoting the grafting of styrene and methacrylic acid, thereby increasing the grafting rate of styrene and methacrylic acid. Then, lime milk is used for neutralization. Lime milk reacts with hydrogen chloride to generate calcium chloride, and can also combine with methacrylate radicals to introduce calcium ions. Calcium chloride, as a Lewis acid, can cooperate with zinc chloride to further promote the removal of hydrogen chloride to release more grafting points, thereby promoting the grafting of dodecyl acrylate and vinyl stearate. Further, the performance of chlorinated polyvinyl chloride is improved. The introduction of calcium ions can improve the weather resistance and high-temperature resistance of chlorinated polyvinyl chloride; (2) The production method of the high-toughness, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride of the present invention uses Tween 80 and styrene in the reaction. Tween 80 can form micelles in the reaction. The lipophilic group in Tween 80 faces the polyvinyl chloride and fixes 1,2-dichloroethane on the surface of the polyvinyl chloride, thereby promoting the swelling of the polyvinyl chloride. It can also combine chlorine and graft monomers in the reaction to promote chlorination and grafting. On the one hand, styrene can be pre-grafted into the polyvinyl chloride to improve the toughness and mechanical strength of the polyvinyl chloride. On the other hand, after pre-grafting, the polyvinyl chloride grafted with styrene can form more active free radicals when grafting with other graft monomers, thereby promoting the grafting of other graft monomers and increasing the grafting rate of other graft monomers; (3) The chlorine content of the chlorinated polyvinyl chloride prepared by the present invention can reach 66.8 - 67.7%; (4) The chlorinated polyvinyl chloride prepared by the present invention has the advantages of high toughness, good weather resistance and high-temperature resistance, and also has excellent mechanical strength, processability and appearance. The appearance is white particles, the notched impact strength is 17.51 - 18.13 kJ / m 2 , the tensile strength is 59.32 - 61.76 MPa, the maximum torque is 14.0 - 14.7 N•m, the plasticizing balance torque is 10.2 - 10.8 N•m. After the weather resistance test, the tensile strength decrease rate is 1.15 - 1.21%, the Vicat softening point is 138.7 - 140.8 °C, and the initial weight loss temperature is 297.2 - 298.4 °C. Specific Embodiments

[0011] In order to have a clearer understanding of the technical features, objectives and effects of the present invention, the specific embodiments of the present invention are now described.

[0012] The room temperature in Examples 1 - 3 and Comparative Examples 1 - 6 is 25 °C.

[0013] Example 1 A production method of high-toughness, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride is specifically as follows: 1. Pretreatment: Add 200 g of polyvinyl chloride and 6 g of zinc oxide to a stirring device, stir at a stirring speed of 50 rpm at room temperature for 30 min, transfer it to a microwave oven and heat it with medium-power microwave for 25 min. The power of the medium-power microwave is 500 W to obtain the pretreated polyvinyl chloride; The polyvinyl chloride is SG-5 type polyvinyl chloride with an average particle size of 120 μm; The average particle size of the zinc oxide is 200 nm; 2. Reaction: After sealing the reaction device, displace the air inside the reaction device with nitrogen. Add all the pretreated polyvinyl chloride obtained in the first step, 24 g of Tween 80, 7 g of styrene, 75 g of 1,2-dichloroethane, and 900 g of deionized water into the reaction device. Stir at a stirring speed of 300 rpm at 75°C for 4 h. Add 0.27 g of azobisisobutyronitrile, 5 g of fumed silica, 3.2 g of an aqueous solution of polyvinyl alcohol, and 7.8 g of methacrylic acid. Then irradiate with ultraviolet light. The power of the ultraviolet light is 500 W and the wavelength is 210 nm. At the same time, introduce chlorine gas at a flow rate of 180 mL / min. The mass ratio of polyvinyl chloride to the total chlorine introduced is 1:0.47. After the introduction is completed, continue to stir for 2 h. Add lime milk to adjust the pH to 6. Raise the temperature to 85°C. Add 0.1 g of azobisisobutyronitrile, 8.5 g of dodecyl acrylate, and 4.4 g of vinyl stearate. Continue to stir for 3 h to obtain the reaction product; The average particle size of the fumed silica is 30 nm; The mass concentration of the aqueous solution of polyvinyl alcohol is 5%, and the model of polyvinyl alcohol is polyvinyl alcohol 1788; The mass concentration of the lime milk is 20%; 3. Post-treatment: After filtering the reaction product by suction, take the filter residue. Neutralize the filter residue with an aqueous solution of sodium bicarbonate, wash it with water, and then dry it under vacuum at 60°C to obtain high-toughness, weather-resistant, and high-temperature-resistant chlorinated polyvinyl chloride; The mass concentration of the aqueous solution of sodium bicarbonate is 5%.

[0014] This example also provides a high-toughness, weather-resistant, and high-temperature-resistant chlorinated polyvinyl chloride prepared by the aforementioned preparation method.

[0015] Example 2 A production method of high-toughness, weather-resistant, and high-temperature-resistant chlorinated polyvinyl chloride is as follows: 1. Pretreatment: Add 210 g of polyvinyl chloride and 6.1 g of zinc oxide into the stirring device. Stir at a stirring speed of 80 rpm at room temperature for 35 min. Transfer it to a microwave oven and heat it with medium-power microwave for 28 min. The power of the medium-power microwave is 500 W to obtain the pretreated polyvinyl chloride; The polyvinyl chloride is SG-5 type polyvinyl chloride with an average particle size of 120 μm; The average particle size of the zinc oxide is 200 nm; 2. Reaction: After sealing the reaction device, displace the air inside the reaction device with nitrogen. Add all the pretreated polyvinyl chloride obtained in the first step, 25 g of Tween 80, 7.2 g of styrene, 78 g of 1,2-dichloroethane, and 920 g of deionized water into the reaction device. Stir at a stirring speed of 350 rpm at 77 °C for 4.5 h. Add 0.29 g of azobisisobutyronitrile, 5.2 g of fumed silica, 3.4 g of an aqueous polyvinyl alcohol solution, and 8 g of methacrylic acid. Then irradiate with ultraviolet light. The power of the ultraviolet light is 500 W and the wavelength is 210 nm. At the same time, introduce chlorine gas at a flow rate of 190 mL / min. The mass ratio of polyvinyl chloride to the total chlorine introduced is 1:0.48. After the introduction is completed, continue stirring for 2.5 h. Add lime milk to adjust the pH to 6.2. Raise the temperature to 87 °C. Add 0.11 g of azobisisobutyronitrile, 8.8 g of dodecyl acrylate, and 4.5 g of vinyl stearate. Continue stirring for 3.5 h to obtain the reaction product; The average particle size of the fumed silica is 30 nm; The mass concentration of the aqueous polyvinyl alcohol solution is 5%, and the model of the polyvinyl alcohol is polyvinyl alcohol 1788; The mass concentration of the lime milk is 20%; 3. Post-treatment: After filtering the reaction product by suction filtration, take the filter residue. Neutralize the filter residue with an aqueous sodium bicarbonate solution, wash it with water, and then dry it under vacuum at 65 °C to obtain high-toughness, weather-resistant, and high-temperature-resistant chlorinated polyvinyl chloride; The mass concentration of the aqueous sodium bicarbonate solution is 5%.

[0016] This example also provides a high-toughness, weather-resistant, and high-temperature-resistant chlorinated polyvinyl chloride prepared by the aforementioned preparation method.

[0017] Example 3 A production method of high-toughness, weather-resistant, and high-temperature-resistant chlorinated polyvinyl chloride, specifically: 1. Pretreatment: Add 230 g of polyvinyl chloride and 6.2 g of zinc oxide to the stirring device. Stir at a stirring speed of 100 rpm at room temperature for 40 min. Transfer it to a microwave oven and heat it with medium-power microwave for 30 min. The power of the medium-power microwave is 500 W to obtain the pretreated polyvinyl chloride; The polyvinyl chloride is SG-5 type polyvinyl chloride with an average particle size of 120 μm; The average particle size of the zinc oxide is 200 nm; 2. Reaction: After sealing the reaction device, displace the air inside the reaction device with nitrogen. Add all the pretreated polyvinyl chloride obtained in the first step, 27 g of Tween 80, 7.5 g of styrene, 80 g of 1,2-dichloroethane, and 950 g of deionized water into the reaction device. Stir at a stirring speed of 400 rpm at 80 °C for 5 h. Then add 0.3 g of azobisisobutyronitrile, 5.3 g of fumed silica, 3.5 g of an aqueous polyvinyl alcohol solution, and 8.2 g of methacrylic acid. Then irradiate with ultraviolet light. The power of the ultraviolet light is 500 W and the wavelength is 210 nm. At the same time, pass chlorine gas into the reaction device at a flow rate of 200 mL / min. The mass ratio of polyvinyl chloride to the total chlorine gas passed is 1:0.5. After the introduction is completed, continue stirring for 2.5 h. Add lime milk to adjust the pH to 6.5, raise the temperature to 90 °C, add 0.11 g of azobisisobutyronitrile, 9 g of dodecyl acrylate, and 4.7 g of vinyl stearate, and continue stirring for 3.5 h to obtain the reaction product; The average particle size of the fumed silica is 30 nm; The mass concentration of the aqueous polyvinyl alcohol solution is 5%, and the model of polyvinyl alcohol is polyvinyl alcohol 1788; The mass concentration of the lime milk is 20%; 3. Post-treatment: After filtering the reaction product by suction filtration, take the filter residue, neutralize the filter residue with an aqueous sodium bicarbonate solution, wash it with water, and then dry it in vacuo at 70 °C to obtain high-toughness, weather-resistant, and high-temperature-resistant chlorinated polyvinyl chloride; The mass concentration of the aqueous sodium bicarbonate solution is 5%.

[0018] This example also provides a high-toughness, weather-resistant, and high-temperature-resistant chlorinated polyvinyl chloride prepared by the aforementioned preparation method.

[0019] Comparative Example 1 On the basis of the preparation method of the high-toughness, weather-resistant, and high-temperature-resistant chlorinated polyvinyl chloride in Example 2, omit the first-step pretreatment step, and in the second-step reaction step, use 210 g of polyvinyl chloride to replace all the pretreated polyvinyl chloride obtained in the first step; The polyvinyl chloride is SG-5 type polyvinyl chloride with an average particle size of 120 μm.

[0020] The rest of the technical solutions are the same as those in Example 2.

[0021] Comparative Example 2 On the basis of the preparation method of the high-toughness, weather-resistant, and high-temperature-resistant chlorinated polyvinyl chloride in Example 2, in the second-step reaction step, change the lime milk to a saturated aqueous sodium bicarbonate solution.

[0022] The rest of the technical solutions are the same as those in Example 2.

[0023] Comparative Example 3 Based on the preparation method of the high-toughness, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride in Example 2, the first-step pretreatment step is omitted, and in the second-step reaction step, 210 g of polyvinyl chloride is used to replace all the pretreated polyvinyl chloride obtained in the first step. At the same time, the lime milk is changed to a saturated sodium bicarbonate aqueous solution; The polyvinyl chloride is SG-5 type polyvinyl chloride with an average particle size of 120 μm.

[0024] The rest of the technical solutions are the same as those in Example 2.

[0025] Comparative Example 4 Based on the preparation method of the high-toughness, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride in Example 2, the use of Tween 80 is omitted in the second-step reaction step.

[0026] The rest of the technical solutions are the same as those in Example 2.

[0027] Comparative Example 5 Based on the preparation method of the high-toughness, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride in Example 2, the use of styrene is omitted in the second-step reaction step.

[0028] The rest of the technical solutions are the same as those in Example 2.

[0029] Comparative Example 6 Based on the preparation method of the high-toughness, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride in Example 2, the use of Tween 80 and styrene is omitted in the second-step reaction step.

[0030] The rest of the technical solutions are the same as those in Example 2.

[0031] Comparative Example 7 Based on the preparation method of the high-toughness, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride in Example 2, in the second-step reaction step, the addition sequence of 7.2 g of styrene is changed to be added simultaneously with 0.11 g of azobisisobutyronitrile, 8.8 g of dodecyl acrylate, and 4.5 g of vinyl stearate. Specifically, the second-step reaction step is changed to: After sealing the reaction device, displace the air in the reaction device with nitrogen. Add all the pretreated polyvinyl chloride obtained in the first step, 25 g of Tween 80, 78 g of 1,2-dichloroethane, and 920 g of deionized water into the reaction device. Stir at a stirring speed of 350 rpm at 77 °C for 4.5 h. Add 0.29 g of azobisisobutyronitrile, 5.2 g of fumed silica, 3.4 g of an aqueous polyvinyl alcohol solution, and 8 g of methacrylic acid, and then irradiate with ultraviolet light. The power of the ultraviolet light is 500 W and the wavelength is 210 nm. At the same time, introduce chlorine gas at a flow rate of 190 mL / min. The mass ratio of polyvinyl chloride to the total chlorine introduced is 1:0.48. After the introduction is completed, continue to stir for 2.5 h. Add lime milk to adjust the pH to 6.2, raise the temperature to 87 °C, add 0.11 g of azobisisobutyronitrile, 7.2 g of styrene, 8.8 g of dodecyl acrylate, and 4.5 g of vinyl stearate, and continue to stir for 3.5 h to obtain the reactant; The average particle size of the fumed silica is 30 nm; The mass concentration of the aqueous polyvinyl alcohol solution is 5%, and the model of polyvinyl alcohol is polyvinyl alcohol 1788; The mass concentration of the lime milk is 20%.

[0032] The rest of the technical solutions are the same as those in Example 2.

[0033] Test Example 1 By the combustion titration method, the chlorine content of the highly tough, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride prepared in Examples 1-3 and Comparative Examples 1-7 was tested. By fully burning the highly tough, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride in oxygen, hydrogen chloride is contained in the generated gas. After absorbing hydrogen chloride with an excessive sodium hydroxide aqueous solution, adjust the pH with a nitric acid aqueous solution, and then use potassium chromate as an indicator and titrate chlorine atoms with a silver nitrate aqueous solution to calculate the chlorine content in the chlorinated polyvinyl chloride. The calculated chlorine content results are as follows:

[0034] From the above results, it can be seen that the chlorine content in the chlorinated polyvinyl chloride of Comparative Examples 1, 3, 4, and 6 is significantly lower than that in the chlorinated polyvinyl chloride of Example 2, indicating that pretreating polyvinyl chloride can promote chlorination, and the use of Tween 80 can also promote chlorination.

[0035] Test Example 2 The appearance of the highly tough, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride prepared in Examples 1-3 and Comparative Examples 1-7 was observed, and the observation results are as follows:

[0036] From the above results, it can be seen that the appearance performance of the chlorinated polyvinyl chloride in Comparative Example 3 is poor.

[0037] Test Example 3 The notched impact strength, tensile strength, maximum torque, and plasticizing balance torque of the highly tough, weather-resistant, and high-temperature-resistant chlorinated polyvinyl chloride prepared in Examples 1-3 and Comparative Examples 1-7 were tested, and the test results are as follows:

[0038] It can be seen from the above results that the test results of the notched impact strength, tensile strength, maximum torque, and plasticizing balance torque of the chlorinated polyvinyl chloride in Comparative Examples 1-7 are all worse than those in Example 2.

[0039] Test Example 4 After testing the tensile strength of the highly tough, weather-resistant, and high-temperature-resistant chlorinated polyvinyl chloride prepared in Examples 1-3 and Comparative Examples 1-7, it was placed in an ultraviolet aging test chamber and continuously irradiated with ultraviolet lamps for 1000 h. Eight ultraviolet lamps with a power of 40 W were used as the light source in the ultraviolet aging test chamber, and the wavelength was 340 nm. Then, the tensile strength was tested, and the tensile strength decrease rate was calculated. The calculation results are as follows:

[0040] It can be seen from the above results that the weather resistance test results of Comparative Examples 1-6 are all worse than those in Example 2.

[0041] Test Example 5 The Vicat softening point and initial weight loss temperature of the highly tough, weather-resistant, and high-temperature-resistant chlorinated polyvinyl chloride prepared in Examples 1-3 and Comparative Examples 1-7 were tested, and the test results are as follows:

[0042] It can be seen from the above results that the high-temperature resistance test results of Comparative Examples 1-6 are all worse than those in Example 2.

Claims

1. A production method of high-toughness, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride, characterized in that It includes: Pretreatment, reaction, and post-treatment; In the said pretreatment, polyvinyl chloride and zinc oxide are added to a stirring device and stirred at room temperature for 30 - 40 min, then heated with medium-power microwave for 25 - 30 min to obtain pretreated polyvinyl chloride; In the said reaction, after sealing the reaction device, the air inside the reaction device is replaced with nitrogen. The pretreated polyvinyl chloride, Tween 80, styrene, 1,2-dichloroethane, and deionized water are added to the reaction device, and stirred at 75 - 80 °C for 4 - 5 h. Then the first portion of azobisisobutyronitrile, fumed silica, polyvinyl alcohol aqueous solution, and methacrylic acid are added, and then irradiated with ultraviolet light while chlorine gas is introduced. After the introduction is completed, stirring continues for 2 - 2.5 h. Lime milk is added to adjust the pH to 6 - 6.5, the temperature is raised to 85 - 90 °C, the second portion of azobisisobutyronitrile, dodecyl acrylate, and vinyl stearate are added, and stirring continues for 3 - 3.5 h to obtain the reaction product.

2. The production method of the high-toughness, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride according to claim 1, characterized in that In the said pretreatment, the mass ratio of polyvinyl chloride to zinc oxide is 200 - 230:6 - 6.

2.

3. The production method of the high-toughness, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride according to claim 1, characterized in that In the said pretreatment, the polyvinyl chloride is SG-5 type polyvinyl chloride with an average particle size of 120 μm; The average particle size of the said zinc oxide is 200 nm; The power of medium-power microwave is 500 W.

4. The production method of the high-toughness, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride according to claim 1, characterized in that, In the said reaction, the mass ratio of Tween 80, styrene, 1,2-dichloroethane, and deionized water is 24 - 27:7 - 7.5:75 - 80:900 - 950.

5. The production method of high-toughness, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride according to claim 1, characterized in that, In the said reaction, the mass ratio of the first portion of azobisisobutyronitrile, fumed silica, polyvinyl alcohol aqueous solution, and methacrylic acid is 0.27 - 0.3:5 - 5.3:3.2 - 3.5:7.8 - 8.2; The mass ratio of the second portion of azobisisobutyronitrile, dodecyl acrylate, and vinyl stearate is 0.1 - 0.11:8.5 - 9:4.4 - 4.7; The mass ratio of styrene, methacrylic acid, and dodecyl acrylate is 7 - 7.5:7.8 - 8.2:8.5 - 9.

6. The production method of high-toughness, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride according to claim 1, characterized in that, The mass ratio of the polyvinyl chloride in the said pretreatment to the deionized water in the said reaction is 200 - 230:900 - 950.

7. The production method of the high-toughness, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride according to claim 1, characterized in that, In the said reaction, the average particle size of the said fumed silica is 30 nm; The mass concentration of the said polyvinyl alcohol aqueous solution is 5%, and the type of polyvinyl alcohol is polyvinyl alcohol 1788; The mass concentration of the said lime milk is 20%; The power of the ultraviolet light is 500 W, and the wavelength is 210 nm.

8. The production method of high-toughness, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride according to claim 1, characterized in that, In the said reaction, when introducing chlorine gas, the flow rate of chlorine gas is 180 - 200 mL / min; The mass ratio of polyvinyl chloride to the total chlorine introduction amount is 1:0.47 - 0.

5.

9. The production method of high-toughness, weather-resistant and high-temperature-resistant chlorinated polyvinyl chloride according to claim 1, characterized in that, In the said post-treatment, after filtering the reaction product by suction, the filter residue is taken, neutralized with sodium bicarbonate aqueous solution, washed with water, and then vacuum dried at 60 - 70 °C to obtain high-toughness, weather-resistant, and high-temperature-resistant chlorinated polyvinyl chloride; The mass concentration of the said sodium bicarbonate aqueous solution is 5%.

10. A high-toughness, weather-resistant, and high-temperature-resistant chlorinated polyvinyl chloride prepared by the preparation method according to any one of claims 1 - 9.

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