A high-toughness, weather-resistant, and high-temperature resistant chlorinated polyvinyl chloride and its production method

Abstract

The invention discloses high-toughness, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride and a production method thereof, belonging to the technical field of chlorinated polyvinyl chloride. The production method comprises: pretreatment, reaction, and post-treatment. In the reaction, after sealing a reaction device, replacing air in the reaction device with nitrogen, adding the pretreated polyvinyl chloride, Tween 80, styrene, 1,2-dichloroethane, and deionized water into the reaction device, stirring at 75-80°C, adding azobisisobutyronitrile, fumed silica, polyvinyl alcohol aqueous solution, and methacrylic acid, then irradiating with ultraviolet light, introducing chlorine, stirring, adding lime milk to adjust the pH to 6-6.5, heating to 85-90°C, adding azobisisobutyronitrile, 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, workability, and appearance.

Description

Technical Field

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

[0002] Chlorinated polyvinyl chloride (CPPVC) is a high-performance polymer material derived from polyvinyl chloride (PVC) through chlorination. It appears as loose white or pale yellow granules or powder. The chlorine content of CPVC is significantly higher than that of PVC, increasing from 56.7% to 60-68%, reaching a maximum of 73.2%. This increase in chlorine content increases molecular irregularity, decreases crystallinity, and strengthens the polarity of the molecular chain, enhancing CPVC's resistance to acid, alkali, and oxidation. It also improves CPVC's high-temperature stability, raising its Vicat softening temperature from 72-82°C (PVC) to 90-125°C. Its maximum operating temperature can reach 110°C, with long-term stable operating temperatures reaching 95°C. CPVC also exhibits excellent low-temperature stability, allowing for use in environments as low as -40°C. CPVC also exhibits excellent weather resistance, flame retardancy, and mechanical strength. It is precisely because of the above-mentioned excellent properties of CPVC that CPVC has been widely used in chemical industry, building materials, aviation, automobile, electrical appliances, textile and other fields.

[0003] However, the following problems exist in the processing and use of chlorinated polyvinyl chloride: First, the melt viscosity of chlorinated polyvinyl chloride is much higher than that of polyvinyl chloride, resulting in great difficulty in processing chlorinated polyvinyl chloride and poor machinability; Second, the melting temperature of chlorinated polyvinyl chloride is close to its thermal decomposition temperature, resulting in a narrow processing temperature range for chlorinated polyvinyl chloride and being very sensitive to processing conditions, requiring strict temperature control. If the processing temperature is too high, degradation is likely to occur during processing, generating hydrogen chloride gas, which 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 machinability of chlorinated polyvinyl chloride; Third, chlorinated polyvinyl chloride is very brittle, especially in low temperature environments.

[0004] In response to the above problems, the commonly used solution is to physically blend or chemically modify CPVC. Among them, physical blending modification is to mix some materials with special properties with CPVC by physical methods to improve the high temperature resistance and toughness of CPVC and reduce the melt viscosity of CPVC. For example, heat stabilizers, processing aids, and impact modifiers are mixed with CPVC by physical methods at the same time. Heat stabilizers mainly include lead salt stabilizers, metal soap stabilizers and organic tin stabilizers. Processing aids are mainly acrylic 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 effectiveness of these impact modifiers is limited. Specifically, MBS and ABS impact modifiers contain unsaturated double bonds in their molecular chains, which reduces the weatherability of CPVC. CPE impact modifiers can also reduce CPVC's high-temperature resistance. Furthermore, thermal stabilizers, processing aids, and impact modifiers all suffer from poor compatibility with CPVC. While their addition improves some properties of CPVC, it negatively impacts other properties. Therefore, using existing physical blending methods, it is difficult to achieve CPVC with excellent weatherability, mechanical strength, processability, and high-temperature resistance.

[0005] Chemical modification involves attaching various grafting monomers, such as low-alkyl acrylates, high-alkyl acrylates, low-alkyl methacrylates, high-alkyl methacrylates, low-alkyl stearates, and styrene, to the side groups or ends of CPVC to impart different properties to the CPVC, further enhancing its overall performance. The main chemical modification methods for CPVC include chlorination followed by grafting and chlorination-in-situ grafting. The aqueous suspension method is primarily used for both chlorination and grafting, given its simplicity and environmental friendliness. Among them, the chlorination-before-grafting method is to first chlorinate polyvinyl chloride to obtain chlorinated polyvinyl chloride, and then use other monomers for grafting to obtain chlorinated polyvinyl chloride. However, during grafting, due to the influence of the number of unstable chlorine on the chlorinated polyvinyl chloride, there are fewer grafting points, and the grafting points are relatively fixed, resulting in a low grafting rate of the product, further resulting in little effect on improving the comprehensive performance of chlorinated polyvinyl chloride; the chlorination in situ grafting method is the most widely used chemical modification method at present. Chlorinated polyvinyl chloride is obtained by grafting during the chlorination process, but chlorination and grafting are competitive reactions, resulting in a low grafting rate of the product, and the reaction is not easy to control, resulting in unstable product quality. In addition, since the hydrogen chloride produced during chlorination by the aqueous suspension method will cause the system to be acidic, if chlorination and grafting are carried out at the same time, the grafted monomer 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-mentioned chlorination in-situ grafting method, after searching, there are three existing solutions: First, in the chlorination in-situ grafting method, the grafting rate is increased by increasing the amount of each grafting monomer, but as the amount of each grafting monomer increases, each grafting monomer undergoes a homopolymerization reaction, and there is competitive grafting between the homopolymer product and other grafting monomers, resulting in little effect on improving the grafting rate of the product, and further, little effect on improving the comprehensive performance of chlorinated polyvinyl chloride; Second, the polyvinyl chloride is pretreated, specifically, the polyvinyl chloride is mixed with an alkaline aqueous solution and reacted at high temperature to remove part of the hydrogen chloride in the polyvinyl chloride to form double bonds, which are easily formed during grafting. It becomes a grafting point, thereby improving the grafting rate, but the residual double bonds will affect the weather resistance and high temperature resistance of chlorinated polyvinyl chloride, and it is also easy to form a coloring group, which affects the appearance of chlorinated polyvinyl chloride; thirdly, the grafting monomer that is not easily hydrolyzed under acidic conditions is first used in the chlorination in situ grafting method, and then the grafting monomer that is easily hydrolyzed under acidic conditions is grafted. However, in the chlorination in situ grafting method, the chlorine free radicals generated by chlorine gas first attack the main chain of polyvinyl chloride to generate polyvinyl chloride free radicals, and then the polyvinyl chloride free radicals combine with the double bonds in the grafting monomer. If grafting is performed separately, the same problem as the chlorination-first-then-grafting method still exists, that is, the problem of low grafting rate. Summary of the Invention

[0007] In response to the shortcomings of the existing technology, the present invention provides a high-toughness, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride and a production method thereof. The prepared chlorinated polyvinyl chloride has the advantages of high toughness, good weather resistance and high-temperature resistance, and also has excellent mechanical strength, workability and appearance.

[0008] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0009] A method for producing high-toughness, weather-resistant, and high-temperature resistant chlorinated polyvinyl chloride, comprising: pretreatment, reaction, and post-treatment;

[0010] The pretreatment comprises adding polyvinyl chloride and zinc oxide to a stirring device, stirring at a stirring speed of 50-100 rpm for 30-40 minutes at room temperature, and heating in a microwave oven at medium heat for 25-30 minutes to obtain pretreated polyvinyl chloride;

[0011] In the pretreatment, the mass ratio of polyvinyl chloride to zinc oxide is 200-230:6-6.2;

[0012] The polyvinyl chloride is SG-5 type polyvinyl chloride with an average particle size of 120 μm;

[0013] The average particle size of the zinc oxide is 200 nm;

[0014] The power of the microwave medium fire is 500W;

[0015] The reaction comprises sealing the reaction apparatus, replacing the air in the reaction apparatus with nitrogen, adding pretreated polyvinyl chloride, Tween 80, styrene, 1,2-dichloroethane, and deionized water to the reaction apparatus, stirring at 75-80° C. and a stirring speed of 300-400 rpm for 4-5 hours, adding a first portion of azobisisobutyronitrile, fumed silica, polyvinyl alcohol aqueous solution, and methacrylic acid, and then irradiating with ultraviolet light while introducing chlorine, continuing stirring for 2-2.5 hours after the introduction, adding lime milk to adjust the pH to 6-6.5, raising the temperature to 85-90° C., adding a second portion of azobisisobutyronitrile, 2-dodecyl acrylate, and vinyl stearate, and continuing stirring for 3-3.5 hours to obtain a reactant;

[0016] 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;

[0017] The mass ratio of the first part 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;

[0018] The mass ratio of the second part of azobisisobutyronitrile, 2-dodecyl acrylate, and vinyl stearate is 0.1-0.11:8.5-9:4.4-4.7;

[0019] The mass ratio of styrene, methacrylic acid, and 2-dodecyl acrylate is 7-7.5:7.8-8.2:8.5-9;

[0020] The mass ratio of the polyvinyl chloride in the pretreatment to the deionized water in the reaction is 200-230:900-950;

[0021] The average particle size of the fumed silica is 30 nm;

[0022] The mass concentration of the polyvinyl alcohol aqueous solution is 5%, and the model of polyvinyl alcohol is polyvinyl alcohol 1788;

[0023] The mass concentration of the lime milk is 20%;

[0024] The power of the UV light is 500W and the wavelength is 210nm;

[0025] When chlorine is introduced, the flow rate of chlorine is 180-200 mL / min;

[0026] The mass ratio of polyvinyl chloride to total chlorine flow is 1:0.47-0.5;

[0027] The post-treatment comprises filtering the reactant, taking the filter residue, neutralizing the filter residue with a sodium bicarbonate aqueous solution, washing the filter residue with water, and then vacuum drying at 60-70° C. to obtain high-toughness, weather-resistant, and high-temperature resistant chlorinated polyvinyl chloride;

[0028] The mass concentration of the sodium bicarbonate aqueous solution is 5%.

[0029] A high-toughness, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride prepared by the above-mentioned preparation method.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The method for producing high-toughness, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride of the present invention utilizes the fact that polyvinyl chloride can be complexed with zinc oxide during microwave heating. Polyvinyl chloride and zinc oxide are mixed and then microwave heated to obtain pretreated polyvinyl chloride. Zinc oxide can combine with the active chlorine of polyvinyl chloride to fix the active chlorine. Then, chlorination and grafting are carried out using the chlorination in situ grafting method. The chlorine free radicals in the chlorination can promote the formation of free radicals, thereby promoting grafting. At the same time, the hydrogen chloride generated in the chlorination reacts with zinc oxide. Zinc chloride, as a Lewis acid, can play a counter-effect, that is, promote the removal of hydrogen chloride from the complexed active chlorine. The zinc chloride reacts with the methacrylic acid to form calcium chloride, which can also combine with the methacrylic acid radical to introduce calcium ions. Calcium chloride, as a Lewis acid, can synergistically act with zinc chloride to further promote the removal of hydrogen chloride to release more grafting points, thereby promoting the grafting of 2-dodecyl acrylate and vinyl stearate, and further improving the performance of chlorinated polyvinyl chloride. The introduction of calcium ions can improve the weather resistance and high temperature resistance of chlorinated polyvinyl chloride.

[0032] (2) The method for producing 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 groups in Tween 80 face the polyvinyl chloride and fix 1,2-dichloroethane on the surface of the polyvinyl chloride, thereby promoting the swelling of the polyvinyl chloride. It can also combine chlorine and grafting 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 grafted with other grafting monomers, thereby promoting the grafting of other grafting monomers and improving the grafting rate of other grafting monomers.

[0033] (3) The chlorine content of the chlorinated polyvinyl chloride prepared by the present invention can reach 66.8-67.7%;

[0034] (4) The chlorinated polyvinyl chloride prepared by the present invention has the advantages of high toughness, good weather resistance and high temperature resistance, as well as excellent mechanical strength, processability and appearance. It is white granular and has a notched impact strength of 17.51-18.13 kJ / m 2 The tensile strength is 59.32-61.76MPa, the maximum torque is 14.0-14.7N•m, the plasticizing equilibrium torque is 10.2-10.8N•m, and after weather resistance testing, the tensile strength decrease rate is 1.15-1.21%, the Vicat softening point is 138.7-140.8℃, and the initial weight loss temperature is 297.2-298.4℃. DETAILED DESCRIPTION

[0035] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described.

[0036] The room temperature in Examples 1-3 and Comparative Examples 1-6 was 25°C.

[0037] Example 1

[0038] A method for producing high-toughness, weather-resistant, and high-temperature resistant chlorinated polyvinyl chloride, specifically comprising:

[0039] 1. Pretreatment: 200 g of polyvinyl chloride and 6 g of zinc oxide were added to a stirring device and stirred at 50 rpm for 30 min at room temperature. The mixture was then heated in a microwave oven at medium heat for 25 min at a power of 500 W to obtain pretreated polyvinyl chloride.

[0040] The polyvinyl chloride is SG-5 type polyvinyl chloride with an average particle size of 120 μm;

[0041] The average particle size of the zinc oxide is 200 nm;

[0042] 2. Reaction: After sealing the reaction apparatus, replace the air in the reaction apparatus with nitrogen, add all the pretreated polyvinyl chloride obtained in step 1, 24g Tween 80, 7g styrene, 75g 1,2-dichloroethane, and 900g deionized water to the reaction apparatus, stir at 75°C at a stirring speed of 300rpm for 4h, add 0.27g azobisisobutyronitrile, 5g fumed silica, 3.2g polyvinyl alcohol aqueous solution, and 7.8g methacrylic acid, and then irradiate with ultraviolet light. The power of the ultraviolet light is 500W and the wavelength is 210nm. At the same time, chlorine is introduced at a flow rate of 180mL / min. The mass ratio of polyvinyl chloride to the total chlorine amount is 1:0.47. After the introduction, continue stirring for 2h, add lime milk to adjust the pH to 6, raise the temperature to 85°C, add 0.1g azobisisobutyronitrile, 8.5g 2-dodecyl acrylate, 4.4 g vinyl stearate, and continued stirring for 3 h to obtain a reactant;

[0043] The average particle size of the fumed silica is 30 nm;

[0044] The mass concentration of the polyvinyl alcohol aqueous solution is 5%, and the model of polyvinyl alcohol is polyvinyl alcohol 1788;

[0045] The mass concentration of the lime milk is 20%;

[0046] 3. Post-treatment: After filtering the reactants, take the filter residue, neutralize it with a sodium bicarbonate aqueous solution, wash it with water, and then vacuum dry it at 60°C to obtain high-toughness, weather-resistant, and high-temperature resistant chlorinated polyvinyl chloride;

[0047] The mass concentration of the sodium bicarbonate aqueous solution is 5%.

[0048] This embodiment also provides a high-toughness, weather-resistant, and high-temperature resistant chlorinated polyvinyl chloride prepared by the aforementioned preparation method.

[0049] Example 2

[0050] A method for producing high-toughness, weather-resistant, and high-temperature resistant chlorinated polyvinyl chloride, specifically comprising:

[0051] 1. Pretreatment: 210 g of polyvinyl chloride and 6.1 g of zinc oxide were added to a stirring device and stirred at 80 rpm at room temperature for 35 min. The mixture was then heated in a microwave oven at medium heat for 28 min at a power of 500 W to obtain pretreated polyvinyl chloride.

[0052] The polyvinyl chloride is SG-5 type polyvinyl chloride with an average particle size of 120 μm;

[0053] The average particle size of the zinc oxide is 200 nm;

[0054] 2. Reaction: After sealing the reaction apparatus, replace the air in the reaction apparatus with nitrogen, add all the pretreated polyvinyl chloride obtained in step 1, 25g Tween 80, 7.2g styrene, 78g 1,2-dichloroethane, and 920g deionized water to the reaction apparatus, stir at 77°C at a stirring speed of 350rpm for 4.5h, add 0.29g azobisisobutyronitrile, 5.2g fumed silica, 3.4g polyvinyl alcohol aqueous solution, and 8g methacrylic acid, and then irradiate with ultraviolet light. The power of the ultraviolet light is 500W and the wavelength is 210nm. At the same time, chlorine is introduced at a flow rate of 190mL / min. The mass ratio of polyvinyl chloride to the total chlorine amount is 1:0.48. After the introduction, continue stirring for 2.5h, add lime milk to adjust the pH to 6.2, raise the temperature to 87°C, add 0.11g azobisisobutyronitrile, 8.8g 2-dodecyl acrylate, 4.5 g of vinyl stearate, and continued stirring for 3.5 h to obtain a reactant;

[0055] The average particle size of the fumed silica is 30 nm;

[0056] The mass concentration of the polyvinyl alcohol aqueous solution is 5%, and the model of polyvinyl alcohol is polyvinyl alcohol 1788;

[0057] The mass concentration of the lime milk is 20%;

[0058] 3. Post-treatment: After filtering the reactants, take the filter residue, neutralize it with a sodium bicarbonate aqueous solution, wash it with water, and then vacuum dry it at 65°C to obtain high-toughness, weather-resistant, and high-temperature resistant chlorinated polyvinyl chloride;

[0059] The mass concentration of the sodium bicarbonate aqueous solution is 5%.

[0060] This embodiment also provides a high-toughness, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride prepared by the aforementioned preparation method.

[0061] Example 3

[0062] A method for producing high-toughness, weather-resistant, and high-temperature resistant chlorinated polyvinyl chloride, specifically comprising:

[0063] 1. Pretreatment: 230 g of polyvinyl chloride and 6.2 g of zinc oxide were added to a stirring device and stirred at 100 rpm at room temperature for 40 min. The mixture was then heated in a microwave oven at medium heat for 30 min at a power of 500 W to obtain pretreated polyvinyl chloride.

[0064] The polyvinyl chloride is SG-5 type polyvinyl chloride with an average particle size of 120 μm;

[0065] The average particle size of the zinc oxide is 200 nm;

[0066] 2. Reaction: After sealing the reaction apparatus, replace the air in the reaction apparatus with nitrogen, add all the pretreated polyvinyl chloride obtained in step 1, 27g Tween 80, 7.5g styrene, 80g 1,2-dichloroethane, and 950g deionized water to the reaction apparatus, stir at 80°C at a stirring speed of 400rpm for 5h, add 0.3g azobisisobutyronitrile, 5.3g fumed silica, 3.5g polyvinyl alcohol aqueous solution, and 8.2g methacrylic acid, and then irradiate with ultraviolet light. The power of the ultraviolet light is 500W and the wavelength is 210nm. At the same time, chlorine is introduced at a flow rate of 200mL / min. The mass ratio of polyvinyl chloride to the total chlorine amount is 1:0.5. After the introduction, continue stirring for 2.5h, add lime milk to adjust the pH to 6.5, raise the temperature to 90°C, add 0.11g azobisisobutyronitrile, 9g 2-dodecyl acrylate, 4.7 g vinyl stearate, and continued stirring for 3.5 h to obtain a reactant;

[0067] The average particle size of the fumed silica is 30 nm;

[0068] The mass concentration of the polyvinyl alcohol aqueous solution is 5%, and the model of polyvinyl alcohol is polyvinyl alcohol 1788;

[0069] The mass concentration of the lime milk is 20%;

[0070] 3. Post-treatment: After filtering the reactants, take the filter residue, neutralize it with a sodium bicarbonate aqueous solution, wash it with water, and then vacuum dry it at 70°C to obtain high-toughness, weather-resistant, and high-temperature resistant chlorinated polyvinyl chloride;

[0071] The mass concentration of the sodium bicarbonate aqueous solution is 5%.

[0072] This embodiment also provides a high-toughness, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride prepared by the aforementioned preparation method.

[0073] Comparative Example 1

[0074] Based on the preparation method of high-toughness, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride in Example 2, the first pretreatment step is omitted, and in the second reaction step, 210g of polyvinyl chloride is used to replace all the pretreated polyvinyl chloride obtained in the first step;

[0075] The polyvinyl chloride is SG-5 type polyvinyl chloride with an average particle size of 120 μm.

[0076] The rest of the technical solutions remain consistent with those in Example 2.

[0077] Comparative Example 2

[0078] Based on the preparation method of high-toughness, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride in Example 2, in the second reaction step, the lime milk is replaced with a saturated sodium bicarbonate aqueous solution.

[0079] The rest of the technical solutions remain consistent with those in Example 2.

[0080] Comparative Example 3

[0081] Based on the preparation method of high-toughness, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride in Example 2, the pretreatment step 1 was omitted, and in the reaction step 2, 210 g of polyvinyl chloride was used instead of all the pretreated polyvinyl chloride obtained in the first step. At the same time, the lime milk was replaced with a saturated sodium bicarbonate aqueous solution;

[0082] The polyvinyl chloride is SG-5 type polyvinyl chloride with an average particle size of 120 μm.

[0083] The rest of the technical solutions remain consistent with those in Example 2.

[0084] Comparative Example 4

[0085] Based on the preparation method of high-toughness, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride in Example 2, the use of Tween 80 is omitted in the second reaction step.

[0086] The rest of the technical solutions remain consistent with those in Example 2.

[0087] Comparative Example 5

[0088] Based on the preparation method of high-toughness, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride in Example 2, the use of styrene is omitted in the second reaction step.

[0089] The rest of the technical solutions remain consistent with those in Example 2.

[0090] Comparative Example 6

[0091] Based on the preparation method of high-toughness, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride in Example 2, in the second reaction step, Tween 80 and styrene are omitted.

[0092] The rest of the technical solutions remain consistent with those in Example 2.

[0093] Comparative Example 7

[0094] Based on the preparation method of high-toughness, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride in Example 2, in the second reaction step, the order of adding 7.2g of styrene was changed to adding it simultaneously with 0.11g of azobisisobutyronitrile, 8.8g of 2-dodecyl acrylate, and 4.5g of vinyl stearate. Specifically, the second reaction step was changed to:

[0095] After the reaction device was sealed, the air in the reaction device was replaced with nitrogen, and all the pretreated polyvinyl chloride obtained in step 1, 25g Tween 80, 78g 1,2-dichloroethane and 920 g of deionized water were added to the reaction apparatus, stirred at 77° C. at a stirring speed of 350 rpm for 4.5 h, 0.29 g of azobisisobutyronitrile, 5.2 g of fumed silica, 3.4 g of a polyvinyl alcohol aqueous solution, and 8 g of methacrylic acid were added, and then irradiated with ultraviolet light, the power of the ultraviolet light was 500 W, the wavelength was 210 nm, and chlorine was introduced at a flow rate of 190 mL / min. The mass ratio of polyvinyl chloride to the total chlorine amount was 1:0.48. After the introduction, stirring was continued for 2.5 h, lime milk was added to adjust the pH to 6.2, the temperature was raised to 87° C., 0.11 g of azobisisobutyronitrile, 7.2 g of styrene, 8.8 g of 2-dodecyl acrylate, and 4.5 g of vinyl stearate were added, and stirring was continued for 3.5 h to obtain a reactant;

[0096] The average particle size of the fumed silica is 30 nm;

[0097] The mass concentration of the polyvinyl alcohol aqueous solution is 5%, and the model of polyvinyl alcohol is polyvinyl alcohol 1788;

[0098] The mass concentration of the lime milk is 20%.

[0099] The rest of the technical solutions remain consistent with those in Example 2.

[0100] Test Example 1

[0101] The chlorine content of the high-toughness, weather-resistant, and high-temperature resistant chlorinated polyvinyl chloride prepared in Examples 1-3 and Comparative Examples 1-7 was tested by combustion titration. The high-toughness, weather-resistant, and high-temperature resistant chlorinated polyvinyl chloride was fully burned in oxygen to generate a gas containing hydrogen chloride. The hydrogen chloride was absorbed by an excess of sodium hydroxide aqueous solution, and the pH was adjusted with a nitric acid aqueous solution. Then, potassium chromate was used as an indicator and the chlorine atoms were titrated with a silver nitrate aqueous solution to calculate the chlorine content in the chlorinated polyvinyl chloride. The calculated chlorine content results are as follows:

[0102]

[0103] It can be seen from the above results that the chlorine content in the chlorinated polyvinyl chloride of Comparative Example 1, Comparative Example 3, Comparative Example 4, and Comparative Example 6 is significantly lower than the chlorine content in the chlorinated polyvinyl chloride of Example 2, indicating that pretreatment of polyvinyl chloride can promote chlorination, and the use of Tween 80 can also promote chlorination.

[0104] Test Example 2

[0105] The appearance of the high-toughness, 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 were as follows:

[0106]

[0107] It can be seen from the above results that the chlorinated polyvinyl chloride of Comparative Example 3 has poor appearance performance.

[0108] Test Example 3

[0109] The notched impact strength, tensile strength, maximum torque, and plasticizing equilibrium torque of the high-toughness, 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:

[0110]

[0111] It can be seen from the above results that the notched impact strength, tensile strength, maximum torque and plasticizing equilibrium torque test results of the chlorinated polyvinyl chloride of Comparative Examples 1-7 are all worse than those of Example 2.

[0112] Test Example 4

[0113] After the tensile strength of the high-toughness, weather-resistant, and high-temperature resistant chlorinated polyvinyl chloride prepared in Examples 1-3 and Comparative Examples 1-7 was tested, the samples were placed in an ultraviolet aging test chamber and irradiated continuously for 1000 hours using an ultraviolet lamp. Eight 40W ultraviolet lamps were used as light sources in the ultraviolet aging test chamber, and the wavelength was 340 nm. The tensile strength was then tested, and the tensile strength decrease rate was calculated. The calculation results are as follows:

[0114]

[0115] It can be seen from the above results that the weather resistance test results of Comparative Examples 1-6 are all worse than that of Example 2.

[0116] Test Example 5

[0117] The Vicat softening point and initial weight loss temperature of the high-toughness, 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:

[0118]

[0119] It can be seen from the above results that the high temperature resistance test results of Comparative Examples 1-6 are all worse than that of Example 2.

Claims

1. A method for producing high-toughness, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride, characterized in that: include: Pretreatment, reaction, post-treatment; The pretreatment comprises adding polyvinyl chloride and zinc oxide into a stirring device, stirring at room temperature for 30-40 minutes, and heating with a microwave at medium heat for 25-30 minutes to obtain pretreated polyvinyl chloride; The reaction comprises sealing the reaction apparatus, replacing the air in the reaction apparatus with nitrogen, adding pretreated polyvinyl chloride, Tween 80, styrene, 1,2-dichloroethane, and deionized water to the reaction apparatus, stirring at 75-80° C. for 4-5 hours, adding a first portion of azobisisobutyronitrile, fumed silica, polyvinyl alcohol aqueous solution, and methacrylic acid, irradiating the reaction apparatus with ultraviolet light, and simultaneously introducing chlorine gas, stirring for 2-2.5 hours after the introduction, adding lime milk to adjust the pH to 6-6.5, raising the temperature to 85-90° C., adding a second portion of azobisisobutyronitrile, 2-dodecyl acrylate, and vinyl stearate, and continuing to stir for 3-3.5 hours to obtain a reactant; The post-treatment comprises filtering the reactant, taking the filter residue, neutralizing the filter residue with a sodium bicarbonate aqueous solution, washing the filter residue with water, and then vacuum drying the filter residue at 60-70° C. to obtain high-toughness, weather-resistant, and high-temperature resistant chlorinated polyvinyl chloride.

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

2.

3. The method for producing high-toughness, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride according to claim 1, characterized in that: In the pretreatment, 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 microwave medium fire is 500W.

4. The method for producing high-toughness, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride according to claim 1, characterized in that: 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.

5. The method for producing high-toughness, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride according to claim 1, characterized in that: In the 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 part of azobisisobutyronitrile, 2-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 2-dodecyl acrylate is 7-7.5:7.8-8.2:8.5-9.

6. The method for producing 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 pretreatment to the deionized water in the reaction is 200-230:900-950.

7. The method for producing high-toughness, weather-resistant and high-temperature resistant chlorinated polyvinyl chloride according to claim 1, characterized in that: In the reaction, 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 polyvinyl alcohol is polyvinyl alcohol 1788; The mass concentration of the lime milk is 20%; The power of the ultraviolet light is 500W and the wavelength is 210nm.

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

5.

9. The method for producing high-toughness, weather-resistant, and high-temperature resistant chlorinated polyvinyl chloride according to claim 1, characterized in that: In the post-treatment, the mass concentration of the sodium bicarbonate aqueous solution is 5%.

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

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