Preparation method of environment-friendly high-fire-resistance polyvinyl chloride

Abstract

The invention discloses a preparation method of environment-friendly high-fire-resistance polyvinyl chloride, and relates to the technical field of new materials, the preparation method comprises the following steps: S1, preparing a waste polyvinyl chloride material, and preparing dechlorinated polyvinyl chloride and epoxy polyvinyl chloride; and S2, weighing polyvinyl chloride, dechlorinated polyvinyl chloride, epoxy polyvinyl chloride, a bio-based plasticizer and a flame retardant, uniformly mixing, uniformly smelting at 120-160 DEG C, putting a sample into a mold, carrying out hot press molding at 150-170 DEG C, and standing for 24-30 hours to obtain the environment-friendly high-fire-resistance polyvinyl chloride. According to the polyvinyl chloride material provided by the invention, the dechlorinated polyvinyl chloride and the epoxy polyvinyl chloride are prepared from the waste polyvinyl chloride material, can be used as heat stabilizers of the polyvinyl chloride, and have relatively strong fire resistance under the synergistic effect of the flame retardant.

Description

Technical Field

[0001] The present application relates to the field of new material technology, and in particular to a method for preparing polyvinyl chloride (PVC) with environmental protection and strong fire resistance. Background Art

[0002] Polyvinyl chloride (PVC) is a high-molecular-weight polymer that appears as a white, amorphous powder at room temperature. It is synthesized from vinyl chloride monomer through polymerization. PVC exhibits excellent mechanical properties, abrasion resistance, flame retardancy, electrical insulation, and chemical resistance. It is also lightweight, easy to process, and has high strength. Its synthetic raw materials are widely available and inexpensive. PVC's excellent overall properties have earned it a broad market share and widespread application in various fields, including agriculture, light industry, building materials, electronics, packaging, and daily necessities, making it a vital component of my country's plastics industry.

[0003] However, the recycling value of PVC is low, and a large amount of PVC material is discarded each year. Incineration of PVC produces dioxin, a highly toxic carcinogen that harms the natural ecosystem and humans. PVC also has poor heat resistance. At high temperatures, the active chlorine atoms are easily converted into HCl, and the mechanical properties of the material also decline as the HCl is removed. This not only leads to a decrease in the material's mechanical properties, but also affects the normal use of PVC products, limiting their application in high-temperature environments. With the advent of green environmental protection concepts, the development of an environmentally friendly and fire-resistant PVC material has become a pressing issue. Summary of the Invention

[0004] In order to provide an environmentally friendly polyvinyl chloride material with excellent fire resistance, the present application provides a method for preparing environmentally friendly and fire-resistant polyvinyl chloride.

[0005] The present application provides a method for preparing polyvinyl chloride with environmental protection and strong fire resistance, which adopts the following technical solution:

[0006] A method for preparing polyvinyl chloride with environmental protection and strong fire resistance comprises the following steps:

[0007] S1. Prepare waste polyvinyl chloride materials to prepare dechlorinated polyvinyl chloride and epoxy polyvinyl chloride;

[0008] S2. Weigh polyvinyl chloride, dechlorinated polyvinyl chloride, epoxy polyvinyl chloride, bio-based plasticizer, and flame retardant, mix well, and refine and plasticize at 120-160°C. Then, place the sample into a mold and hot-press it at 150-170°C. After standing for 24-30 hours, environmentally friendly and fire-resistant polyvinyl chloride is obtained.

[0009] Preferably, the preparation method of epoxy polyvinyl chloride comprises the following steps:

[0010] After mixing dechlorinated polyvinyl chloride with formic acid, add concentrated sulfuric acid dropwise, heat to 65-75°C in a water bath, then add hydrogen peroxide solution dropwise, keep the temperature constant and react for 4-6 hours; after the reaction is completed, filter to obtain a solid product, rinse the product with sodium hydroxide solution and distilled water several times, and vacuum dry at 40-50°C for 5-7 hours to obtain epoxy polyvinyl chloride.

[0011] Preferably, the mass ratio of the dechlorinated polyvinyl chloride, formic acid, concentrated sulfuric acid, and hydrogen peroxide solution is 3-5:0.72-1.2:0.12-0.2:6.6-11.

[0012] Preferably, the dechlorinated polyvinyl chloride is prepared from the following raw materials in parts by weight: 50-100 parts of solid sodium hydroxide, 100-210 parts of ethanol, 50-100 parts of waste polyvinyl chloride materials, and 150-300 parts of deionized water.

[0013] Preferably, the method for preparing dechlorinated polyvinyl chloride comprises the following steps:

[0014] Solid sodium hydroxide is added to ethanol, dissolved by ultrasonication, and then transferred to a hydrothermal autoclave equipped with a polytetrafluoroethylene liner. The waste polyvinyl chloride material is washed and dried, and then added to the polytetrafluoroethylene liner. After sealing, it is heated to 120-150°C in an oil bath and reacted for 4-6 hours. After the reaction is completed, deionized water is added to the product to obtain a suspension. The suspension is filtered to obtain a solid product. The product is washed with water several times and then vacuum dried at 40-50°C for 5-7 hours to obtain dechlorinated polyvinyl chloride.

[0015] Preferably, the bio-based plasticizer is a citrate plasticizer.

[0016] Preferably, the method for preparing the flame retardant comprises the following steps:

[0017] The method comprises the following steps: mixing 50-60 parts of water, 4-6 parts of ethanol and 1.5-2.5 parts of aluminate coupling agent by weight, stirring for 10-20 minutes, then heating to 55-65°C, adding 25-35 parts of flame retardant material, and continuing stirring for 30-50 minutes under nitrogen protection; then adding 5-7 parts of butyl acrylate and 0.1-0.2 parts of AIBN initiator, and reacting for 1-2 hours; then adding 5-7 parts of methyl methacrylate and 0.2-0.3 parts of AIBN initiator, and continuing the reaction for 3-5 hours; after the reaction is completed, using ethanol as a solvent, purifying at 75-85°C for 24-30 hours, and drying at 70-80°C to obtain a flame retardant.

[0018] Preferably, the flame retardant material includes magnesium hydroxide, aluminum hydroxide, and zinc borate, and the mass ratio of the three is 1:0.8-1:0.2-0.4.

[0019] Preferably, the mass percentages of the polyvinyl chloride, dechlorinated polyvinyl chloride, epoxy polyvinyl chloride, bio-based plasticizer and flame retardant are respectively 40-50% polyvinyl chloride, 10-15% dechlorinated polyvinyl chloride, 10-20% epoxy polyvinyl chloride, 15-20% bio-based plasticizer and 5-10% flame retardant.

[0020] Preferably, the mass percentages of the polyvinyl chloride, dechlorinated polyvinyl chloride, epoxy polyvinyl chloride, bio-based plasticizer, and flame retardant are respectively 45% polyvinyl chloride, 13% dechlorinated polyvinyl chloride, 17% epoxy polyvinyl chloride, 17% bio-based plasticizer, and 8% flame retardant.

[0021] In summary, this application includes at least one of the following beneficial technical effects:

[0022] 1. The present application utilizes waste polyvinyl chloride materials, and performs wet dechlorination treatment on the waste polyvinyl chloride materials in a sodium hydroxide alcohol solution to obtain dechlorinated polyvinyl chloride; the dechlorinated polyvinyl chloride is then subjected to epoxidation treatment using formic acid and hydrogen peroxide as oxygen supply agents and concentrated sulfuric acid as a catalyst to obtain epoxy polyvinyl chloride; epoxy polyvinyl chloride can replace the more active chlorine atoms in polyvinyl chloride, and can absorb hydrogen chloride produced by the decomposition of polyvinyl chloride, inhibiting its catalytic effect on thermal decomposition, thereby improving the thermal stability of polyvinyl chloride; dechlorinated polyvinyl chloride contains a large number of conjugated double bonds, and can also undergo addition reaction with hydrogen chloride, thereby inhibiting further thermal decomposition; the present application uses dechlorinated polyvinyl chloride and epoxy polyvinyl chloride obtained from waste polyvinyl chloride materials as stabilizers for polyvinyl chloride, and these two materials can not only effectively inhibit the thermal decomposition reaction of polyvinyl chloride at high temperatures, but also realize the efficient recycling of waste, reduce pollution to the environment, and comply with the green and environmentally friendly industrial development concept;

[0023] 2. This application uses an aluminate coupling agent to hybridize magnesium hydroxide, aluminum hydroxide, and zinc borate, and then further grafts and polymerizes them using methyl methacrylate and butyl acrylate to obtain a flame retardant that is a hybrid of inorganic and organic matter, which effectively improves the fire resistance of polyvinyl chloride materials. DETAILED DESCRIPTION

[0024] The present application is further described in detail below with reference to the embodiments.

[0025] The chemical reagents used in the preparation examples, embodiments and comparative examples provided in the present invention are all commercially available products.

[0026] Preparation Example Preparation of flame retardant

[0027] Preparation Example 1

[0028] 50g of water, 4g of ethanol, and 1.5g of aluminate coupling agent were mixed and stirred for 10 minutes, then heated to 55°C, 25g of flame retardant material was added, and stirring was continued for 30 minutes under nitrogen protection; then 5g of butyl acrylate and 0.1g of AIBN initiator were added and reacted for 1 hour; then 5g of methyl methacrylate and 0.2g of AIBN initiator were added and the reaction was continued for 3 hours; after the reaction was completed, ethanol was used as a solvent, purified at 75°C for 24 hours, and then dried at 70°C to obtain a flame retardant;

[0029] The flame retardant materials used in this preparation example include magnesium hydroxide, aluminum hydroxide, and zinc borate, and the mass ratio of the three is 1:0.8:0.4.

[0030] Preparation Example 2

[0031] 60g of water, 6g of ethanol, and 2.5g of aluminate coupling agent were mixed and stirred for 20 minutes, then heated to 65°C, 35g of flame retardant material was added, and stirring was continued for 50 minutes under nitrogen protection; then 7g of butyl acrylate and 0.2g of AIBN initiator were added, and the reaction was continued for 2 hours; then 7g of methyl methacrylate and 0.3g of AIBN initiator were added, and the reaction was continued for 5 hours; after the reaction was completed, ethanol was used as a solvent, purified at 85°C for 30 hours, and then dried at 80°C to obtain a flame retardant;

[0032] The flame retardant materials used in this preparation example include magnesium hydroxide, aluminum hydroxide, and zinc borate, and the mass ratio of the three is 1:0.8:0.4.

[0033] Preparation Example 3

[0034] The difference between Preparation Example 3 and Preparation Example 1 is that the mass ratio of the flame retardant materials magnesium hydroxide, aluminum hydroxide, and zinc borate in Preparation Example 3 is 1:0.9:0.3.

[0035] Preparation Example 4

[0036] The difference between Preparation Example 4 and Preparation Example 1 is that the mass ratio of the flame retardant materials magnesium hydroxide, aluminum hydroxide, and zinc borate in Preparation Example 4 is 1:1:0.2.

[0037] Preparation Example 5

[0038] The difference between Preparation Example 5 and Preparation Example 1 is that the mass ratio of the flame retardant materials magnesium hydroxide, aluminum hydroxide, and zinc borate in Preparation Example 5 is 1:0.6:0.6.

[0039] Preparation Example 6

[0040] The difference between Preparation Example 6 and Preparation Example 1 is that the mass ratio of the flame retardant materials magnesium hydroxide, aluminum hydroxide, and zinc borate in Preparation Example 6 is 1:1.1:0.1.

[0041] Example 1

[0042] S1. Prepare waste polyvinyl chloride materials and prepare dechlorinated polyvinyl chloride and epoxy polyvinyl chloride. The preparation method is as follows:

[0043] S1.1. Preparation of dechlorinated polyvinyl chloride:

[0044] 100 g of solid sodium hydroxide was added to 210 g of ethanol, and after ultrasonic dissolution, the mixture was transferred to a hydrothermal autoclave equipped with a polytetrafluoroethylene liner. 100 g of waste polyvinyl chloride material was washed with water and dried, and then added to the polytetrafluoroethylene liner. After sealing, the mixture was heated to 120° C. in an oil bath and reacted for 6 h. After the reaction was completed, 300 g of deionized water was added to the product to obtain a suspension. The suspension was filtered to obtain a solid product. The product was washed with water three times and then vacuum dried at 50° C. for 5 h to obtain dechlorinated polyvinyl chloride.

[0045] S1.2. Preparation of epoxy polyvinyl chloride:

[0046] 50 g of the dechlorinated polyvinyl chloride prepared in S1.1 was mixed with 12 g of formic acid, and 2 g of concentrated sulfuric acid was added dropwise. The mixture was heated to 75°C in a water bath, and then 110 g of a 30% by mass aqueous hydrogen peroxide solution was added dropwise. The temperature was maintained constant and the reaction was continued for 6 h. After the reaction, a solid product was obtained by filtration. The product was rinsed several times with sodium hydroxide solution and distilled water, and then vacuum dried at 50°C for 5 h to obtain epoxy polyvinyl chloride.

[0047] S2. Weigh 40 g of polyvinyl chloride, 15 g of dechlorinated polyvinyl chloride prepared by S1.1, 25 g of epoxy polyvinyl chloride prepared by S1.2, 15 g of bio-based plasticizer, and 5 g of flame retardant prepared by Preparation Example 1, mix them evenly, and use a double-roller to plasticize them evenly at 120 ° C. Then, place the sample into a mold and hot-press it on a hot press at 150 ° C. After standing for 24 hours, environmentally friendly and fire-resistant polyvinyl chloride is obtained;

[0048] The bio-based plasticizer used in this embodiment is acetyl tributyl citrate, purchased from Shanghai MacLean Biochemical Technology Co., Ltd., with the serial number: T819551.

[0049] Example 2

[0050] S1. Prepare waste polyvinyl chloride materials and prepare dechlorinated polyvinyl chloride and epoxy polyvinyl chloride. The preparation method is as follows:

[0051] S1.1. Preparation of dechlorinated polyvinyl chloride:

[0052] 100 g of solid sodium hydroxide was added to 210 g of ethanol, and after ultrasonic dissolution, the mixture was transferred to a hydrothermal autoclave equipped with a polytetrafluoroethylene liner. 100 g of waste polyvinyl chloride material was washed with water and dried, and then added to the polytetrafluoroethylene liner. After sealing, the mixture was heated to 120° C. in an oil bath and reacted for 6 h. After the reaction was completed, 300 g of deionized water was added to the product to obtain a suspension. The suspension was filtered to obtain a solid product. The product was washed with water three times and then vacuum dried at 50° C. for 5 h to obtain dechlorinated polyvinyl chloride.

[0053] S1.2. Preparation of epoxy polyvinyl chloride:

[0054] 50 g of the dechlorinated polyvinyl chloride prepared in S1.1 was mixed with 12 g of formic acid, and 2 g of concentrated sulfuric acid was added dropwise. The mixture was heated to 75°C in a water bath, and then 110 g of a 30% by mass aqueous hydrogen peroxide solution was added dropwise. The temperature was maintained constant and the reaction was continued for 6 h. After the reaction, a solid product was obtained by filtration. The product was rinsed several times with sodium hydroxide solution and distilled water, and then vacuum dried at 50°C for 5 h to obtain epoxy polyvinyl chloride.

[0055] S2. Weigh 45g of polyvinyl chloride, 13g of dechlorinated polyvinyl chloride prepared by S1.1, 17g of epoxy polyvinyl chloride prepared by S1.2, 17g of bio-based plasticizer, and 8g of the flame retardant prepared in Preparation Example 1, mix them evenly, and use a double-roll plasticizer to plasticize evenly at 120°C. Then, place the sample into a mold and hot-press it on a hot press at 150°C. After standing for 24 hours, environmentally friendly and fire-resistant polyvinyl chloride is obtained;

[0056] The bio-based plasticizer used in this embodiment is acetyl tributyl citrate, purchased from Shanghai MacLean Biochemical Technology Co., Ltd., with the serial number: T819551.

[0057] Example 3

[0058] S1. Prepare waste polyvinyl chloride materials and prepare dechlorinated polyvinyl chloride and epoxy polyvinyl chloride. The preparation method is as follows:

[0059] S1.1. Preparation of dechlorinated polyvinyl chloride:

[0060] 100 g of solid sodium hydroxide was added to 210 g of ethanol, and after ultrasonic dissolution, the mixture was transferred to a hydrothermal autoclave equipped with a polytetrafluoroethylene liner. 100 g of waste polyvinyl chloride material was washed with water and dried, and then added to the polytetrafluoroethylene liner. After sealing, the mixture was heated to 120° C. in an oil bath and reacted for 6 h. After the reaction was completed, 300 g of deionized water was added to the product to obtain a suspension. The suspension was filtered to obtain a solid product. The product was washed with water three times and then vacuum dried at 50° C. for 5 h to obtain dechlorinated polyvinyl chloride.

[0061] S1.2. Preparation of epoxy polyvinyl chloride:

[0062] 50 g of the dechlorinated polyvinyl chloride prepared in S1.1 was mixed with 12 g of formic acid, and 2 g of concentrated sulfuric acid was added dropwise. The mixture was heated to 75°C in a water bath, and then 110 g of a 30% by mass aqueous hydrogen peroxide solution was added dropwise. The temperature was maintained constant and the reaction was continued for 6 h. After the reaction, a solid product was obtained by filtration. The product was rinsed several times with sodium hydroxide solution and distilled water, and then vacuum dried at 50°C for 5 h to obtain epoxy polyvinyl chloride.

[0063] S2. Weigh 50 g of polyvinyl chloride, 10 g of dechlorinated polyvinyl chloride prepared by S1.1, 10 g of epoxy polyvinyl chloride prepared by S1.2, 20 g of bio-based plasticizer, and 10 g of the flame retardant prepared in Preparation Example 1, mix them evenly, and use a double-roller to plasticize them evenly at 120 ° C. Then, place the sample into a mold and hot-press it at 150 ° C on a hot press. After standing for 24 hours, environmentally friendly and fire-resistant polyvinyl chloride is obtained;

[0064] The bio-based plasticizer used in this embodiment is acetyl tributyl citrate, purchased from Shanghai MacLean Biochemical Technology Co., Ltd., with the serial number: T819551.

[0065] Example 4

[0066] S1. Prepare waste polyvinyl chloride materials and prepare dechlorinated polyvinyl chloride and epoxy polyvinyl chloride. The preparation method is as follows:

[0067] S1.1. Preparation of dechlorinated polyvinyl chloride:

[0068] 75 g of solid sodium hydroxide was added to 150 g of ethanol, and after ultrasonic dissolution, the mixture was transferred to a hydrothermal autoclave equipped with a polytetrafluoroethylene liner. 75 g of waste polyvinyl chloride material was washed with water and dried, and then added to the polytetrafluoroethylene liner. After sealing, the mixture was heated to 135° C. in an oil bath and reacted for 5 h. After the reaction, 225 g of deionized water was added to the product to obtain a suspension. The suspension was filtered to obtain a solid product. The product was washed with water 4 times and then vacuum dried at 45° C. for 6 h to obtain dechlorinated polyvinyl chloride.

[0069] S1.2. Preparation of epoxy polyvinyl chloride:

[0070] 40 g of the dechlorinated polyvinyl chloride prepared in S1.1 was mixed with 9.6 g of formic acid, and 1.6 g of concentrated sulfuric acid was added dropwise. The mixture was heated to 70°C in a water bath, and then 88 g of a 30% by mass aqueous hydrogen peroxide solution was added dropwise. The temperature was maintained constant and the reaction was allowed to proceed for 5 h. After the reaction, a solid product was obtained by filtration. The product was rinsed several times with sodium hydroxide solution and distilled water, and then vacuum dried at 45°C for 6 h to obtain epoxy polyvinyl chloride.

[0071] S2. Weigh 40 g of polyvinyl chloride, 15 g of dechlorinated polyvinyl chloride prepared by S1.1, 25 g of epoxy polyvinyl chloride prepared by S1.2, 15 g of bio-based plasticizer, and 5 g of the flame retardant prepared in Preparation Example 1, mix them evenly, and use a double-roller to plasticize them evenly at 140 ° C. Then, place the sample into a mold and hot-press it on a hot press at 160 ° C. After standing for 27 hours, environmentally friendly and fire-resistant polyvinyl chloride is obtained;

[0072] The bio-based plasticizer used in this embodiment is acetyl tributyl citrate, purchased from Shanghai MacLean Biochemical Technology Co., Ltd., with the serial number: T819551.

[0073] Example 5

[0074] S1. Prepare waste polyvinyl chloride materials and prepare dechlorinated polyvinyl chloride and epoxy polyvinyl chloride. The preparation method is as follows:

[0075] S1.1. Preparation of dechlorinated polyvinyl chloride:

[0076] 50 g of solid sodium hydroxide was added to 100 g of ethanol, and after ultrasonic dissolution, the mixture was transferred to a hydrothermal autoclave equipped with a polytetrafluoroethylene liner. 50 g of waste polyvinyl chloride material was washed with water and dried, and then added to the polytetrafluoroethylene liner. After sealing, the mixture was heated to 150° C. in an oil bath and reacted for 4 h. After the reaction, 150 g of deionized water was added to the product to obtain a suspension. The suspension was filtered to obtain a solid product. The product was washed with water 5 times and then vacuum dried at 40° C. for 7 h to obtain dechlorinated polyvinyl chloride.

[0077] S1.2. Preparation of epoxy polyvinyl chloride:

[0078] 30 g of the dechlorinated polyvinyl chloride prepared in S1.1 was mixed with 7.2 g of formic acid, and 1.2 g of concentrated sulfuric acid was added dropwise. The mixture was heated to 65°C in a water bath, and then 66 g of a 30% by mass aqueous hydrogen peroxide solution was added dropwise. The temperature was maintained constant and the reaction was allowed to proceed for 4 h. After the reaction, a solid product was obtained by filtration. The product was rinsed several times with sodium hydroxide solution and distilled water, and then vacuum dried at 40°C for 7 h to obtain epoxy polyvinyl chloride.

[0079] S2. Weigh 40 g of polyvinyl chloride, 15 g of dechlorinated polyvinyl chloride prepared by S1.1, 25 g of epoxy polyvinyl chloride prepared by S1.2, 15 g of bio-based plasticizer, and 5 g of flame retardant prepared in Preparation Example 1, mix them evenly, and use a double-roll plasticizer to plasticize them evenly at 160 ° C. Then, place the sample into a mold and hot-press it on a hot press at 170 ° C. After standing for 30 hours, environmentally friendly and fire-resistant polyvinyl chloride is obtained;

[0080] The bio-based plasticizer used in this embodiment is acetyl tributyl citrate, purchased from Shanghai MacLean Biochemical Technology Co., Ltd., with the serial number: T819551.

[0081] Example 6

[0082] The difference between Example 6 and Example 1 is that the flame retardant used in Example 6 is prepared from Preparation Example 2.

[0083] Example 7

[0084] The difference between Example 7 and Example 1 is that the flame retardant used in Example 7 is prepared from Preparation Example 3.

[0085] Example 8

[0086] The difference between Example 8 and Example 1 is that the flame retardant used in Example 8 is prepared by Preparation Example 4.

[0087] Example 9

[0088] The difference between Example 9 and Example 1 is that the flame retardant used in Example 9 is prepared from Preparation Example 5.

[0089] Example 10

[0090] The difference between Example 10 and Example 1 is that the flame retardant used in Example 10 is prepared from Preparation Example 6.

[0091] Comparative Example 1

[0092] The difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, no dechlorinated polyvinyl chloride is added to S2, and an equal amount of epoxy polyvinyl chloride is used instead.

[0093] Comparative Example 2

[0094] The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, epoxy polyvinyl chloride is not added to S2, and an equal amount of dechlorinated polyvinyl chloride is used instead.

[0095] Comparative Example 3

[0096] The difference between Comparative Example 3 and Example 1 is that in Comparative Example 3, epoxy polyvinyl chloride and dechlorinated polyvinyl chloride are not added to S2, and an equal amount of polyvinyl chloride is used instead.

[0097] Comparative Example 4

[0098] The difference between Comparative Example 4 and Example 1 is that in Comparative Example 4, no flame retardant is added to S2, and an equal amount of polyvinyl chloride is used instead.

[0099] Performance testing

[0100] 1. With reference to GB / T 1040.2-2022 “Determination of tensile properties of plastics Part 2: Test conditions for molded and extruded plastics”, the tensile strength of the polyvinyl chloride obtained in Examples 1-10 and Comparative Examples 1-4 was tested, and the results are shown in Table 1.

[0101] 2. With reference to GB / T 2406.2-2009 "Plastics - Determination of Combustion Behavior by Oxygen Index Method - Part 2: Room Temperature Test", the oxygen index of the polyvinyl chloride obtained in Examples 1-10 and Comparative Examples 1-4 was tested. The results are shown in Table 1.

[0102] 3. The vertical flame retardancy ratings of the polyvinyl chlorides obtained in Examples 1-10 and Comparative Examples 1-4 were tested with reference to UL 94 standard. The results are shown in Table 1.

[0103] The specific test results are as follows:

[0104] Table 1 Performance test results

[0105]

[0106]

[0107] It can be seen from the test results in Table 1 that the tensile strength of the polyvinyl chloride provided in this application can reach more than 30 MPa, the mechanical properties are excellent, the limiting oxygen index can reach 34% and above, and the vertical flame retardant grade can be V-0, indicating strong fire resistance.

[0108] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for preparing polyvinyl chloride with environmental protection and strong fire resistance, characterized by: The following steps are involved: S1. Prepare waste polyvinyl chloride materials to prepare dechlorinated polyvinyl chloride and epoxy polyvinyl chloride; S2. Weigh polyvinyl chloride, dechlorinated polyvinyl chloride, epoxy polyvinyl chloride, bio-based plasticizer, and flame retardant, mix well, and refine and plasticize at 120-160°C. Then, place the sample into a mold and hot-press it at 150-170°C. After standing for 24-30 hours, environmentally friendly and fire-resistant polyvinyl chloride is obtained.

2. The method for preparing environmentally friendly and fire-resistant polyvinyl chloride according to claim 1, characterized in that: The preparation method of the epoxy polyvinyl chloride comprises the following steps: After mixing dechlorinated polyvinyl chloride with formic acid, add concentrated sulfuric acid dropwise, heat to 65-75°C in a water bath, then add hydrogen peroxide solution dropwise, keep the temperature constant and react for 4-6 hours; after the reaction is completed, filter to obtain a solid product, rinse the product with sodium hydroxide solution and distilled water several times, and vacuum dry at 40-50°C for 5-7 hours to obtain epoxy polyvinyl chloride.

3. The method for preparing environmentally friendly and fire-resistant polyvinyl chloride according to claim 2, characterized in that: The mass ratio of the dechlorinated polyvinyl chloride, formic acid, concentrated sulfuric acid and hydrogen peroxide solution is 3-5:0.72-1.2:0.12-0.2:6.6-11.

4. The method for preparing environmentally friendly and fire-resistant polyvinyl chloride according to claim 1 or 2, characterized in that: The dechlorinated polyvinyl chloride is prepared from the following raw materials in parts by weight: 50-100 parts of solid sodium hydroxide, 100-210 parts of ethanol, 50-100 parts of waste polyvinyl chloride materials, and 150-300 parts of deionized water.

5. The method for preparing environmentally friendly and fire-resistant polyvinyl chloride according to claim 4, characterized in that: The preparation method of the dechlorinated polyvinyl chloride comprises the following steps: Solid sodium hydroxide is added to ethanol, dissolved by ultrasonication, and then transferred to a hydrothermal autoclave equipped with a polytetrafluoroethylene liner. The waste polyvinyl chloride material is washed and dried, and then added to the polytetrafluoroethylene liner. After sealing, it is heated to 120-150°C in an oil bath and reacted for 4-6 hours. After the reaction is completed, deionized water is added to the product to obtain a suspension. The suspension is filtered to obtain a solid product. The product is washed with water several times and then vacuum dried at 40-50°C for 5-7 hours to obtain dechlorinated polyvinyl chloride.

6. The method for preparing environmentally friendly and fire-resistant polyvinyl chloride according to claim 1, characterized in that: The bio-based plasticizer is a citrate plasticizer.

7. The method for preparing environmentally friendly and fire-resistant polyvinyl chloride according to claim 1, characterized in that: The preparation method of the flame retardant comprises the following steps: The method comprises the following steps: mixing 50-60 parts of water, 4-6 parts of ethanol and 1.5-2.5 parts of aluminate coupling agent by weight, stirring for 10-20 minutes, then heating to 55-65°C, adding 25-35 parts of flame retardant material, and continuing stirring for 30-50 minutes under nitrogen protection; then adding 5-7 parts of butyl acrylate and 0.1-0.2 parts of AIBN initiator, and reacting for 1-2 hours; then adding 5-7 parts of methyl methacrylate and 0.2-0.3 parts of AIBN initiator, and continuing the reaction for 3-5 hours; after the reaction is completed, using ethanol as a solvent, purifying at 75-85°C for 24-30 hours, and drying at 70-80°C to obtain a flame retardant.

8. The method for preparing environmentally friendly and fire-resistant polyvinyl chloride according to claim 7, characterized in that: The flame retardant material comprises magnesium hydroxide, aluminum hydroxide and zinc borate, and the mass ratio of the three is 1:0.8-1:0.2-0.

4.

9. The method for preparing environmentally friendly and fire-resistant polyvinyl chloride according to claim 1, characterized in that: The weight percentages of the polyvinyl chloride, dechlorinated polyvinyl chloride, epoxy polyvinyl chloride, bio-based plasticizer, and flame retardant are respectively 40-50% of polyvinyl chloride, 10-15% of dechlorinated polyvinyl chloride, 10-20% of epoxy polyvinyl chloride, 15-20% of bio-based plasticizer, and 5-10% of flame retardant.

10. The method for preparing environmentally friendly and fire-resistant polyvinyl chloride according to claim 9, characterized in that: The weight percentages of the polyvinyl chloride, dechlorinated polyvinyl chloride, epoxy polyvinyl chloride, bio-based plasticizer, and flame retardant are respectively 45% of polyvinyl chloride, 13% of dechlorinated polyvinyl chloride, 17% of epoxy polyvinyl chloride, 17% of bio-based plasticizer, and 8% of flame retardant.

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