High-elasticity pressure-resistant PVC material and preparation method thereof

Abstract

The application relates to the technical field of polyvinyl chloride, and discloses a high-elasticity pressure-resistant PVC material and a preparation method thereof, wherein calcium carbonate powder and modified lignin carboxylate are added into a mixer, stirred and mixed, then polyvinyl chloride, a plasticizer, a stabilizer, a lubricating aid and zinc oxide are added, stirred and mixed, the mixture is placed in a double-roller plasticating machine, a foaming agent and a foaming regulator are added after mixing, the mixture is sheeted after mixing, and the sheet is placed in a flat vulcanizing machine, hot-pressed, and cold-pressed to obtain the high-elasticity pressure-resistant PVC material. The modified lignin carboxylate plays the role of a dispersant, performs surface modification and coating on the calcium carbonate powder, is beneficial to reducing the agglomeration of the calcium carbonate, and contains a large amount of ester groups, forms hydrogen bond interaction with chlorine atoms of the polyvinyl chloride, improves the compatibility between the polyvinyl chloride and the modified lignin carboxylate modified calcium carbonate, and improves the tensile property, compression resistance and other mechanical properties of the foaming material.

Description

Technical Field

[0001] This invention relates to the field of polyvinyl chloride technology, specifically to a highly elastic and pressure-resistant PVC material and its preparation method. Background Technology

[0002] Polyvinyl chloride (PVC) foam materials possess advantages such as low density, lightweight, high wear resistance, cushioning and shock absorption, sound and heat insulation, and waterproofing and moisture resistance, making them suitable for applications in shoe sole materials, insulation boards, and foamed sealing strips. To improve the durability of PVC foam materials and enhance their practical applications in shoe soles and other areas, it is necessary to improve their mechanical strength, resistance to compression deformation, and elasticity. This is typically achieved by reinforcing and modifying them with high-performance rubbers and inorganic fillers, such as nitrile rubber, EPDM rubber, calcium carbonate, and barium carbonate. Calcium carbonate is inexpensive, has high mechanical strength, and good structural stability, making it widely used in rubber and plastics. However, when used in small amounts, its reinforcing effect on materials is limited. Excessive use, on the other hand, can lead to agglomeration and poor compatibility with polyvinyl chloride (PVC), thus affecting the reinforcing effect. Adding dispersants can solve these problems; examples include stearic acid, silane coupling agents, and sodium polyacrylate. Lignin, a natural biomass resource, is inexpensive, readily available, and has high heat resistance. It also contains phenolic hydroxyl groups, exhibiting high reactivity and ease of chemical modification, making it widely used in dispersants and other applications. Summary of the Invention

[0003] Technical problem solved: In view of the shortcomings of the prior art, the present invention provides a high-elasticity and pressure-resistant PVC material and its preparation method, which solves the problem of poor strength and pressure resistance of polyvinyl chloride foam materials.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a high-elasticity and pressure-resistant PVC material, comprising polyvinyl chloride, calcium carbonate powder, modified lignin carboxylate, plasticizer, stabilizer, foaming agent, foaming regulator, lubricant, and zinc oxide in a ratio of 100g:(20-40)g:(1.2-2.5)g:(45-60)g:(2-3)g:(2.8-4)g:(4-5)g:(1.7-2.4)g:(2.2-2.8)g.

[0005] The preparation method of lignin carboxylate is as follows: Add 2-3 mol / L sodium hydroxide aqueous solution and lignin to a flask, stir, and then add a modifier. The ratio of lignin to modifier is 100 g: (0.1-0.25) mol. Heat to 45-50℃, stir for 5-8 h, add hydrochloric acid dropwise to neutralize the pH to 7.5, heat to evaporate until a precipitate forms, then cool in an ice-water bath, filter, wash the precipitate with ice water, and dry to obtain modified lignin carboxylate. The reaction formula is as follows: .

[0006] Furthermore, the plasticizers include dioctyl phthalate, diisononyl phthalate, and diisodecyl phthalate.

[0007] Furthermore, the foaming agent includes azodicarbonamide.

[0008] Furthermore, the foaming regulator includes acrylate copolymer ACR foaming regulator.

[0009] Furthermore, stabilizers include tribasic lead sulfate and dibasic lead phosphite.

[0010] Furthermore, the lubricant includes any one or more of stearic acid, zinc stearate, polyethylene wax, and paraffin.

[0011] Further, the modifier is prepared as follows: Dichloromethane, 4-dimethylaminopyridine, succinic anhydride, and 3-chloro-1,2-propanediol in a ratio of (2-2.2) mol:(8-12) mol:1 mol are added to a flask. The mixture is stirred at 20-30℃ for 24-36 h. The solvent is removed by rotary evaporation, and the residue is separated by silica gel column chromatography to obtain the modifier. The reaction formula is as follows: .

[0012] Furthermore, the preparation method of high-elasticity and pressure-resistant PVC material is as follows: Add calcium carbonate powder and modified lignin carboxylate to a mixer, stir and mix at 50-80℃ for 10-20 minutes, then add polyvinyl chloride, plasticizer, stabilizer, lubricant and zinc oxide, stir and mix at 100-110℃ for 8-10 minutes, place the mixture in a two-roll plasticizer, with a shaft temperature of 115-120℃, and mix for 3-5 minutes, then add foaming agent and foaming regulator, mix and extrude the mixture into sheets, place it in a flat vulcanizing machine, hot press at 165-170℃ and 8-10MPa for 8-12 minutes, and cold press for 5-7 minutes after mold opening to obtain high-elasticity and pressure-resistant PVC material.

[0013] The beneficial technical effects of addressing the above-mentioned technical problems are as follows: A modifier containing multiple carboxyl and ester groups undergoes an etherification reaction with the phenolic hydroxyl groups of lignin to obtain a modified lignin carboxylate containing a large number of carboxyl groups. During the mixing process, the carboxyl groups act as anchoring groups, enabling the lignin carboxylate to function as a dispersant, thus modifying and coating the surface of calcium carbonate powder. This helps reduce the agglomeration of calcium carbonate. Furthermore, the modified lignin carboxylate contains a large number of ester groups, which form hydrogen bonds with the chlorine atoms of polyvinyl chloride (PVC), significantly improving the compatibility between PVC and the modified lignin carboxylate-modified calcium carbonate. The calcium carbonate is uniformly dispersed in the PVC foam material, providing better reinforcement and improving the tensile properties, tear strength, compression resistance, and elasticity of the foam material, making it suitable as a high-performance shoe sole material. Detailed Implementation

[0014] The following polyvinyl chloride (PVC) grades are listed: HS-1300, Shandong Ousheng Chemical. Calcium carbonate powder is 1250 mesh. Lignin (CAS number 8068-03-9), Nantong Runfeng Petrochemical. ACR foaming agent (grade P-530A), Dongguan Donglin Polymer Materials.

[0015] Example 1: A method for preparing a highly elastic and pressure-resistant PVC material: (1) Add 140 mL of dichloromethane, 20 mmol of catalyst 4-dimethylaminopyridine, 100 mmol of succinic anhydride and 10 mmol of 3-chloro-1,2-propanediol to a flask, stir the reaction at 20 °C for 36 h, remove the solvent by rotary evaporation, separate the residue by silica gel column chromatography, and obtain the modifier by using a petroleum ether solution of ethyl acetate as the mobile phase.

[0016] (2) Add 16 mL of 2 mol / L sodium hydroxide aqueous solution and 5 g of lignin to the flask, heat to 50 °C, stir for 1 h, add 7.5 mmol of modifier, continue the reaction for 5 h, add 4% hydrochloric acid to neutralize the pH to 7.5, heat to evaporate until precipitate is formed, then cool in an ice-water bath, filter and wash the precipitate with ice water, dry to obtain modified lignin carboxylate.

[0017] (3) Add 100g of calcium carbonate powder and 6g of modified lignin carboxylate to the mixer and stir at 50°C for 20min. Then add 500g of polyvinyl chloride, 250g of dioctyl phthalate, 8g of tribasic lead sulfate, 4g of dibasic lead phosphite, 4g of stearic acid, 6.7g of paraffin wax and 11g of zinc oxide. Stir at 110°C for 8min. Place the mixture in a two-roll plasticizer with a shaft temperature of 115°C and mix for 4min. Then add 17g of azodicarbonamide and 20g of ACR foaming regulator. After mixing, sheet out and place in a flat vulcanizing machine. Hot press at 165°C and 10MPa for 8min. After opening the mold, cold press for 6min to obtain a high-elasticity and pressure-resistant PVC material.

[0018] Example 2, a method for preparing a highly elastic and pressure-resistant PVC material: (1) Add 130 mL of dichloromethane, 22 mmol of catalyst 4-dimethylaminopyridine, 80 mmol of succinic anhydride and 10 mmol of 3-chloro-1,2-propanediol to a flask, stir and react at 30 °C for 24 h, remove the solvent by rotary evaporation, separate the residue by silica gel column chromatography, and obtain the modifier by using a petroleum ether solution of ethyl acetate as the mobile phase.

[0019] (2) Add 15 mL of 2 mol / L sodium hydroxide aqueous solution and 7 g of lignin to the flask, heat to 45 °C, stir for 1 h, add 7 mmol of modifier, continue the reaction for 7 h, add 4% hydrochloric acid to neutralize the pH to 7.5, heat to evaporate until precipitate is formed, then cool in an ice-water bath, filter and wash the precipitate with ice water, dry to obtain modified lignin carboxylate.

[0020] (3) Add 130g of calcium carbonate powder and 8g of modified lignin carboxylate to the mixer and stir at 50°C for 20min. Then add 500g of polyvinyl chloride, 225g of dioctyl phthalate, 9.6g of tribasic lead sulfate, 5.4g of dibasic lead phosphite, 3.8g of stearic acid, 7.6g of paraffin wax and 14g of zinc oxide. Stir at 100°C for 10min. Place the mixture in a two-roll plasticizer with a shaft temperature of 115°C and mix for 5min. Then add 14g of azodicarbonamide and 22g of ACR foaming regulator. After mixing, sheet out and place in a flat vulcanizing machine. Hot press at 165°C and 10MPa for 12min. After opening the mold, cold press for 7min to obtain a high-elasticity and pressure-resistant PVC material.

[0021] Example 3, a method for preparing a highly elastic and pressure-resistant PVC material: (1) Add 250 mL of dichloromethane, 44 mmol of catalyst 4-dimethylaminopyridine, 200 mmol of succinic anhydride and 20 mmol of 3-chloro-1,2-propanediol to a flask, stir the reaction at 20 °C for 36 h, remove the solvent by rotary evaporation, separate the residue by silica gel column chromatography, and obtain the modifier by using a petroleum ether solution of ethyl acetate as the mobile phase.

[0022] (2) Add 30 mL of 2 mol / L sodium hydroxide aqueous solution and 6 g of lignin to the flask, heat to 45 °C, stir for 1 h, add 15 mmol of modifier, continue the reaction for 8 h, add 4% hydrochloric acid to neutralize the pH to 7.5, heat to evaporate until precipitate is formed, then cool in an ice-water bath, filter and wash the precipitate with ice water, dry to obtain modified lignin carboxylate.

[0023] (3) Add 170g of calcium carbonate powder and 10g of modified lignin carboxylate to the mixer and stir at 80°C for 10min. Then add 500g of polyvinyl chloride, 300g of dioctyl phthalate, 6.5g of tribasic lead sulfate, 3.5g of dibasic lead phosphite, 3.2g of stearic acid, 5.3g of polyethylene wax and 12g of zinc oxide. Stir at 100°C for 10min. Place the mixture in a two-roll plasticizer with a shaft temperature of 115°C and mix for 5min. Then add 17g of azodicarbonamide and 25g of ACR foaming regulator. After mixing, sheet out and place in a flat vulcanizing machine. Hot press at 170°C and 8MPa for 12min. After opening the mold, cold press for 5min to obtain a high-elasticity and pressure-resistant PVC material.

[0024] Example 4, a method for preparing a highly elastic and pressure-resistant PVC material: (1) Add 250 mL of dichloromethane, 40 mmol of catalyst 4-dimethylaminopyridine, 240 mmol of succinic anhydride and 20 mmol of 3-chloro-1,2-propanediol to a flask, stir the reaction at 25 °C for 36 h, remove the solvent by rotary evaporation, separate the residue by silica gel column chromatography, and obtain the modifier by using a petroleum ether solution of ethyl acetate as the mobile phase.

[0025] (2) Add 22 mL of 3 mol / L sodium hydroxide aqueous solution and 8 g of lignin to the flask, heat to 50 °C, stir for 1 h, add 16 mmol of modifier, continue the reaction for 6 h, add 4% hydrochloric acid to neutralize the pH to 7.5, heat to evaporate until precipitate is formed, then cool in an ice-water bath, filter and wash the precipitate with ice water, dry to obtain modified lignin carboxylate.

[0026] (3) Add 200g of calcium carbonate powder and 12.5g of modified lignin carboxylate to the mixer and stir at 60°C for 20min. Then add 500g of polyvinyl chloride, 270g of dioctyl phthalate, 8g of tribasic lead sulfate, 5g of dibasic lead phosphite, 4g of stearic acid, 7g of polyethylene wax and 12g of zinc oxide. Stir at 100°C for 10min. Place the mixture in a two-roll plasticizer with a shaft temperature of 120°C and mix for 3min. Then add 20g of azodicarbonamide and 24g of ACR foaming regulator. After mixing, sheet out and place in a flat vulcanizing machine. Hot press at 170°C and 8MPa for 12min. After opening the mold, cold press for 7min to obtain a high-elasticity and pressure-resistant PVC material.

[0027] Comparative Example 1 differs from Example 1 in that lignin is used instead of modified lignin carboxylate.

[0028] (1) Add 100g of calcium carbonate powder and 6g of lignin to the mixer and stir at 50°C for 20 minutes. Then add 500g of polyvinyl chloride, 250g of dioctyl phthalate, 8g of tribasic lead sulfate, 4g of dibasic lead phosphite, 4g of stearic acid, 6.7g of paraffin wax and 11g of zinc oxide. Stir at 110°C for 8 minutes. Place the mixture in a two-roll plasticizer with a shaft temperature of 115°C and mix for 4 minutes. Then add 17g of azodicarbonamide and 20g of ACR foaming regulator. After mixing, sheet out and place in a flat vulcanizing machine. Hot press at 165°C and 10MPa for 8 minutes. After opening the mold, cold press for 6 minutes to obtain PVC material.

[0029] Comparative Example 2 differs from Example 1 in that chloroacetic acid is used instead of the modifier.

[0030] (1) Add 16 mL of 2 mol / L sodium hydroxide aqueous solution and 5 g of lignin to a flask, heat to 50 °C, stir for 1 h, add 7.5 mmol of chloroacetic acid, continue the reaction for 5 h, add 4% hydrochloric acid dropwise to neutralize the pH to 7.5, heat to evaporate until a precipitate is formed, then cool in an ice-water bath, filter, wash the precipitate with ice water, and dry to obtain modified lignin carboxylate.

[0031] (2) Add 100g of calcium carbonate powder and 6g of modified lignin carboxylate to the mixer and stir at 50°C for 20min. Then add 500g of polyvinyl chloride, 250g of dioctyl phthalate, 8g of tribasic lead sulfate, 4g of dibasic lead phosphite, 4g of stearic acid, 6.7g of paraffin wax and 11g of zinc oxide. Stir at 110°C for 8min. Place the mixture in a two-roll plasticizer with a shaft temperature of 115°C and mix for 4min. Then add 17g of azodicarbonamide and 20g of ACR foaming regulator. After mixing, sheet out and place in a flat vulcanizing machine. Hot press at 165°C and 10MPa for 8min. After opening the mold, cold press for 6min to obtain PVC material.

[0032] Comparative Example 3 differs from Example 1 in that ethyl chloroacetate is used instead of the modifier.

[0033] (1) Add 16 mL of 2 mol / L sodium hydroxide aqueous solution and 5 g of lignin to a flask, heat to 50 °C, stir for 1 h, add 7.5 mmol of ethyl chloroacetate, continue the reaction for 5 h, add 4% hydrochloric acid dropwise to neutralize the pH to 7.5, heat to evaporate until a precipitate is formed, then cool in an ice-water bath, filter, wash the precipitate with ice water, and dry to obtain modified lignin.

[0034] (2) Add 100g of calcium carbonate powder and 6g of modified lignin to the mixer and stir at 50°C for 20 minutes. Then add 500g of polyvinyl chloride, 250g of dioctyl phthalate, 8g of tribasic lead sulfate, 4g of dibasic lead phosphite, 4g of stearic acid, 6.7g of paraffin wax, and 11g of zinc oxide. Stir at 110°C for 8 minutes. Place the mixture in a two-roll plasticizer with a shaft temperature of 115°C and mix for 4 minutes. Then add 17g of azodicarbonamide and 20g of ACR foaming regulator. After mixing, sheet out and place in a flat vulcanizing machine. Hot press at 165°C and 10MPa for 8 minutes. After opening the mold, cold press for 6 minutes to obtain PVC material.

[0035] The compressive properties of PVC materials are tested according to GB / T 6669-2008. Tensile properties are tested according to GB / T 6344-2008. Tear strength is tested according to GB / T 10808-2006.

[0036] Table 1 permanent compression deformation (%) Tensile strength (MPa) Elongation at break (%) Tear strength (kN / m) Example 1 9.4 12.8 235.1 32.4 Example 2 6.8 16.0 246.7 47.2 Example 3 8.3 17.9 196.6 43.8 Example 4 6.1 14.5 281.6 41.3 Comparative Example 1 11.3 10.2 193.0 27.2 Comparative Example 2 10.2 11.7 212.4 30.5 Comparative Example 3 10.9 10.6 201.8 28.7 In each embodiment, modified lignin carboxylates are added to the PVC foam material. These carboxylates contain a large number of carboxylate groups. During the mixing process, they act as a dispersant to modify and coat the surface of calcium carbonate powder, which helps to reduce the aggregation of calcium carbonate. At the same time, the modified lignin introduces a large number of ester groups, which form hydrogen bonds with the chlorine atoms of polyvinyl chloride, significantly improving the compatibility between polyvinyl chloride and calcium carbonate modified by modified lignin carboxylates. Calcium carbonate is uniformly dispersed in the PVC foam material, providing better reinforcement and significantly improving the tensile properties and tear strength of the foam material, reducing compression set, and improving compression resistance and elasticity.

[0037] The lignin in Comparative Example 1 does not contain carboxyl groups, making it difficult to modify the surface of calcium carbonate and thus failing to improve its dispersibility and agglomeration problems. Furthermore, the lignin does not contain ester groups, resulting in low interfacial interaction with polyvinyl chloride, which leads to poor tensile properties, tear strength, and compression properties of the PVC foam material.

[0038] The modified lignin carboxylate in Comparative Example 2 does not contain ester groups. After surface modification of calcium carbonate, it has poor compatibility with polyvinyl chloride, resulting in poor tensile properties, tear strength, compression properties, etc. of PVC foam material.

[0039] The modified lignin in Comparative Example 3 does not contain carboxyl groups, making it difficult to modify the surface of calcium carbonate and thus failing to improve its dispersibility and agglomeration problems, resulting in poor tensile properties, tear strength, and compression properties of the PVC foam material.

Claims

1. A highly elastic and pressure-resistant PVC material, characterized in that, The high-elasticity and pressure-resistant PVC material comprises polyvinyl chloride, calcium carbonate powder, modified lignin carboxylate, plasticizer, stabilizer, foaming agent, foaming regulator, lubricant, and zinc oxide in a ratio of 100g:(20-40)g:(1.2-2.5)g:(45-60)g:(2-3)g:(2.8-4)g:(4-5)g:(1.7-2.4)g:(2.2-2.8)g. The preparation method of the lignin carboxylate is as follows: add sodium hydroxide aqueous solution and lignin to a flask, stir and add modifier to carry out reaction, add hydrochloric acid dropwise to neutralize, heat and evaporate until precipitate is formed, then cool in an ice water bath, filter and wash the precipitate with ice water, dry to obtain modified lignin carboxylate. The structural formula of the modifier is as follows: .

2. The high-elasticity and pressure-resistant PVC material according to claim 1, characterized in that, The plasticizer is any one or more of dioctyl phthalate, diisononyl phthalate, and diisodecyl phthalate.

3. The high-elasticity and pressure-resistant PVC material according to claim 1, characterized in that, The foaming agent is azodicarbonamide, and the foaming regulator is acrylate copolymer ACR foaming regulator.

4. The high-elasticity and pressure-resistant PVC material according to claim 1, characterized in that, The stabilizer is any one or more of tribasic lead sulfate and dibasic lead phosphite.

5. The high-elasticity and pressure-resistant PVC material according to claim 1, characterized in that, The lubricant is any one or more of stearic acid, zinc stearate, polyethylene wax, and paraffin.

6. The high-elasticity and pressure-resistant PVC material according to claim 1, characterized in that, The concentration of the sodium hydroxide aqueous solution is 2-3 mol / L.

7. The high-elasticity and pressure-resistant PVC material according to claim 1, characterized in that, The ratio of lignin to modifier is 100g:(0.1-0.25)mol.

8. The high-elasticity and pressure-resistant PVC material according to claim 1, characterized in that, The reaction temperature is 45-50℃, and the reaction time is 5-8h.

9. The high-elasticity and pressure-resistant PVC material according to claim 7, characterized in that, The modifier is prepared by adding dichloromethane, 4-dimethylaminopyridine, succinic anhydride, and 3-chloro-1,2-propanediol in a ratio of (2-2.2) mol: (8-12) mol: 1 mol to a flask, stirring the mixture at 20-30°C for 24-36 h, removing the solvent by rotary evaporation, and separating the residue by silica gel column chromatography to obtain the modifier.

10. A method for preparing a highly elastic and pressure-resistant PVC material as described in any one of claims 1-8, characterized in that, The preparation method is as follows: calcium carbonate powder and modified lignin carboxylate are added to a mixer and stirred at 50-80℃ for 10-20 minutes. Then, polyvinyl chloride, plasticizer, stabilizer, lubricant and zinc oxide are added and stirred at 100-110℃ for 8-10 minutes. The mixture is placed in a two-roll plasticizer with a shaft temperature of 115-120℃ and mixed for 3-5 minutes. Then, foaming agent and foaming regulator are added and mixed. After sheeting, the sheet is placed in a flat vulcanizing machine and hot-pressed at 165-170℃ and 8-10MPa for 8-12 minutes. After mold opening, it is cold-pressed for 5-7 minutes to obtain a high-elasticity and pressure-resistant PVC material.

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