An environmentally friendly, oil-resistant PVC slipper material and its preparation process

Abstract

This invention relates to the field of polyvinyl chloride (PVC) footwear technology, and discloses an environmentally friendly, oil-resistant PVC slipper material and its preparation process. The PVC slipper material of this invention, by weight, comprises 70-85 parts PVC, 15-30 parts nitrile rubber, 23-30 parts plasticizer, 2-3.5 parts GMA-grafted CPE, and 1.8-3 parts carboxyl-terminated polyacrylonitrile, etc. During high-temperature mixing, the epoxy groups of the GMA-grafted CPE side chains undergo ring-opening initiation with the carboxyl groups of the polyacrylonitrile, thereby introducing the polyacrylonitrile molecular chain into the side chains of the chlorinated polyethylene (CPE), forming a polyacrylonitrile-CPE polymer. This polymer acts as a compatibilizer, improving the compatibility between PVC and nitrile rubber, resulting in higher tensile strength and tear strength in the PVC slipper material, as well as low oil absorption and excellent oil resistance.

Description

Technical Field

[0001] This invention relates to the field of polyvinyl chloride (PVC) footwear technology, specifically to an environmentally friendly, oil-resistant PVC slipper material and its preparation process. Background Technology

[0002] Polyvinyl chloride (PVC) possesses excellent wear resistance, electrical insulation, and corrosion resistance, and its production cost is relatively low, making it widely used in shoe sole materials, wires and cables, packaging materials, and pipes. However, traditional PVC shoe sole materials suffer from poor mechanical strength, susceptibility to cracking, and poor oil resistance. Modifying PVC with rubber materials, such as nitrile rubber, styrene-butadiene rubber, ethylene propylene diene monomer (EPDM) rubber, and polyurethane rubber, can improve the overall performance of PVC.

[0003] Nitrile rubber (NBR) possesses excellent oil resistance, abrasion resistance, and heat resistance. Combining NBR with polyvinyl chloride (PVC) leverages the advantages of both, resulting in a composite material with superior performance. Chinese patent CN114196134B discloses a women's shoe with a cold-resistant sole and its preparation method. Using modified PVC, powdered NBR, and ethyl para-aminobenzoate as raw materials, the prepared sole material exhibits excellent cold resistance. However, this patent does not improve the tensile properties, tear strength, or other mechanical properties of the PVC sole material. Summary of the Invention

[0004] This invention solves the problem of poor mechanical properties of PVC slipper materials.

[0005] The technical solution of the present invention is as follows: an environmentally friendly and oil-resistant PVC slipper material, characterized in that, by weight, the PVC slipper material comprises 70-85 parts of polyvinyl chloride, 15-30 parts of nitrile rubber, 23-30 parts of plasticizer, 2-3.5 parts of GMA-grafted CPE, 1.8-3 parts of carboxyl-terminated polyacrylonitrile, 2.2-3 parts of heat stabilizer, 3-5 parts of foaming agent, 0.2-0.3 parts of crosslinking agent, 1.3-2 parts of filler, 0.8-1.3 parts of additives, and 1.2-1.6 parts of antioxidant.

[0006] Furthermore, the plasticizer is dioctyl terephthalate, the heat stabilizer is calcium-zinc stabilizer, the foaming agent is azodicarbonamide, the crosslinking agent is dicumyl peroxide, the filler is zinc oxide, and the antioxidant is antioxidant 4100NA. The additives are any one or a combination of stearic acid and zinc stearate.

[0007] Furthermore, the preparation process of GMA-grafted CPE is as follows: by weight, 100 parts of chlorinated polyethylene, 2-5 parts of glycidyl methacrylate, and 0.3-0.6 parts of dicumyl peroxide are added to a torque rheometer, and the grafting is carried out at 170-175℃ for 6-10 min. After cooling, the product is added to xylene, heated under reflux, filtered, and then extracted with acetone in a Soxhlet extractor to obtain GMA-grafted CPE.

[0008] Further, the preparation process of carboxyl-terminated polyacrylonitrile is as follows: N,N-dimethylformamide, 100 parts acrylonitrile, 2.2-3.5 parts S,S'-bis(α,α'-methyl-α"-acetic acid)trithiocarbonate, and 0.22-0.3 parts azobisisobutyronitrile are added to a reaction vessel by weight. The mixture is heated to 65-75℃ under a nitrogen atmosphere and reacted for 12-18 hours. The solution is then diluted with ethanol, filtered, washed with ethanol, and dried to obtain carboxyl-terminated polyacrylonitrile. The reaction formula is:

[0009]

[0010] Furthermore, the preparation process of the environmentally friendly and oil-resistant PVC slipper material is as follows: Nitrile rubber is placed in a two-roller plasticizer for plasticizing, and then polyvinyl chloride, plasticizer, GMA-grafted CPE, carboxyl-terminated polyacrylonitrile, heat stabilizer, filler, additives, and antioxidant are added and mixed at 100-110℃ for 10-15 minutes. Foaming agent and crosslinking agent are added and mixed again, and the mixture is discharged. Finally, foaming is carried out in an injection molding machine at a temperature of 180-210℃, a pressure of 10-15MPa, and a time of 8-10 minutes. After cooling, the environmentally friendly and oil-resistant PVC slipper material is obtained.

[0011] The technical effects of this invention: This invention involves high-temperature mixing, vulcanization, and foaming of polyvinyl chloride (PVC), nitrile rubber (NBR), GMA-grafted CPE, carboxyl-terminated polyacrylonitrile (PPB), plasticizer, heat stabilizer, and fillers to obtain an environmentally friendly, oil-resistant PVC slipper material. During the high-temperature mixing process, the epoxy groups of the GMA-grafted CPE side chains initiate ring-opening with the terminal carboxyl groups of the PPB, thereby introducing the PPB molecular chain into the side chains of the chlorinated polyethylene (CPE), forming a PPB-CPE polymer. Due to the good compatibility between chlorinated polyethylene and PVC, and the similar polarity between the PPB molecular chains in the side chains and the PPB block molecular chains in NBR, the PPB-grafted CPE acts as a compatibilizer, further improving the compatibility between PVC and NBR. This results in PVC slipper material with higher tensile strength and tear strength, as well as low oil absorption and excellent oil resistance. Detailed Implementation

[0012] To make the objectives, technical solutions, and beneficial effects of the present invention clearer, the preferred embodiments of the present invention will be described in detail below to facilitate understanding by those skilled in the art.

[0013] The following products are from Dongguan Zhengtao Plastics Co., Ltd.: Polyvinyl chloride (PVCP440), Nitrile rubber (NBR3305E), Chlorinated polyethylene (CPE7100), and Calcium-zinc stabilizer (MC91717KA / 2).

[0014] Example 1:

[0015] (1) 200g of chlorinated polyethylene, 7g of glycidyl methacrylate and 0.9g of dicumyl peroxide were added to a torque rheometer and fused at 170℃ for 10min. After cooling, the product was added to xylene, heated and refluxed, filtered, and then extracted with acetone in a Soxhlet extractor to obtain GMA-grafted CPE.

[0016] (2) Add 150 mL of N,N-dimethylformamide, 100 g of acrylonitrile, 2.8 g of S,S'-bis(α,α'-methyl-α"-acetic acid) trithiocarbonate and 0.26 g of azobisisobutyronitrile to the reaction vessel. Heat to 65 °C under a nitrogen atmosphere and react for 18 h. Dilute the solution with ethanol, filter, wash with ethanol, and dry to obtain carboxyl-terminated polyacrylonitrile.

[0017] (3) Place 1.5 kg of nitrile rubber in a two-roll plasticizer for plasticizing, then add 8.5 kg of polyvinyl chloride, 3 kg of plasticizer dioctyl terephthalate, 200 g of GMA-grafted CPE, 180 g of carboxyl-terminated polyacrylonitrile, 300 g of calcium-zinc stabilizer, 160 g of filler zinc oxide, 70 g of stearic acid, 30 g of zinc stearate, and 120 g of antioxidant 4100NA. Mix at 100°C for 15 min, then add 500 g of foaming agent azodicarbonamide and 20 g of crosslinking agent dicumyl peroxide for mixing and discharge. Finally, foam in an injection molding machine at 180°C, 10 MPa, and 10 min, then cool to obtain environmentally friendly and oil-resistant PVC slipper material.

[0018] Example 2:

[0019] (1) 200g of chlorinated polyethylene, 10g of glycidyl methacrylate and 1.2g of dicumyl peroxide were added to a torque rheometer and melt-grafted at 175℃ for 8min. After cooling, the product was added to xylene, heated and refluxed, filtered, and then extracted with acetone in a Soxhlet extractor to obtain GMA-grafted CPE.

[0020] (2) Add 150 mL of N,N-dimethylformamide, 100 g of acrylonitrile, 3.5 g of S,S'-bis(α,α'-methyl-α"-acetic acid) trithiocarbonate and 0.3 g of azobisisobutyronitrile to the reaction vessel, heat to 70 °C in a nitrogen atmosphere, react for 18 h, add ethanol to dilute the solution, filter, wash with ethanol, and dry to obtain carboxyl-terminated polyacrylonitrile.

[0021] (3) Place 2kg of nitrile rubber in a two-roll plasticizer for plasticizing, then add 8kg of polyvinyl chloride, 2.6kg of plasticizer dioctyl terephthalate, 300g of GMA-grafted CPE, 250g of carboxyl-terminated polyacrylonitrile, 270g of calcium-zinc stabilizer, 130g of filler zinc oxide, 80g of stearic acid, 30g of zinc stearate, and 130g of antioxidant 4100NA. Mix at 110℃ for 10min, then add 420g of foaming agent azodicarbonamide and 28g of crosslinking agent dicumyl peroxide for mixing and discharge. Finally, foam in an injection molding machine at 210℃, 15MPa, and 8min, then cool to obtain environmentally friendly and oil-resistant PVC slipper material.

[0022] Example 3:

[0023] (1) 200g of chlorinated polyethylene, 4g of glycidyl methacrylate and 0.6g of dicumyl peroxide were added to a torque rheometer and melt-grafted at 170℃ for 6min. After cooling, the product was added to xylene, heated and refluxed, filtered, and then extracted with acetone in a Soxhlet extractor to obtain GMA-grafted CPE.

[0024] (2) Add 100 mL of N,N-dimethylformamide, 100 g of acrylonitrile, 2.2 g of S,S'-bis(α,α'-methyl-α"-acetic acid) trithiocarbonate and 0.22 g of azobisisobutyronitrile to the reaction vessel. Heat to 75 °C under a nitrogen atmosphere and react for 12 h. Dilute the solution with ethanol, filter, wash with ethanol, and dry to obtain carboxyl-terminated polyacrylonitrile.

[0025] (3) Place 3kg of nitrile rubber in a two-roll plasticizer for plasticizing, then add 7kg of polyvinyl chloride, 2.3kg of plasticizer dioctyl terephthalate, 350g of GMA-grafted CPE, 300g of carboxyl-terminated polyacrylonitrile, 220g of calcium-zinc stabilizer, 200g of filler zinc oxide, 50g of stearic acid, 50g of zinc stearate, and 160g of antioxidant 4100NA. Mix at 110℃ for 12min, then add 300g of foaming agent azodicarbonamide and 30g of crosslinking agent dicumyl peroxide for mixing and discharge. Finally, foam in an injection molding machine at 190℃, 15MPa, and 8min, then cool to obtain environmentally friendly and oil-resistant PVC slipper material.

[0026] Comparative Example 1: The difference between this comparative example and Example 1 is that GMA-grafted CPE and carboxyl-terminated polyacrylonitrile are not added.

[0027] (1) Place 1.5 kg of nitrile rubber in a two-roll plasticizer for plasticizing, then add 8.5 kg of polyvinyl chloride, 3 kg of plasticizer dioctyl terephthalate, 300 g of calcium zinc stabilizer, 160 g of filler zinc oxide, 70 g of stearic acid, 30 g of zinc stearate, and 120 g of antioxidant 4100NA. Mix at 100°C for 15 min, then add 500 g of foaming agent azodicarbonamide and 20 g of crosslinking agent dicumyl peroxide for mixing and discharge. Finally, foam in an injection molding machine at 180°C, 10 MPa, and 10 min, then cool to obtain environmentally friendly and oil-resistant PVC slipper material.

[0028] Comparative Example 2: The difference between this comparative example and Example 1 is that GMA-grafted CPE is not added.

[0029] (1) Place 1.5 kg of nitrile rubber in a two-roll plasticizer for plasticizing, then add 8.5 kg of polyvinyl chloride, 3 kg of plasticizer dioctyl terephthalate, 180 g of carboxyl-terminated polyacrylonitrile, 300 g of calcium zinc stabilizer, 160 g of filler zinc oxide, 70 g of stearic acid, 30 g of zinc stearate, and 120 g of antioxidant 4100NA. Mix at 100°C for 15 min, then add 500 g of foaming agent azodicarbonamide and 20 g of crosslinking agent dicumyl peroxide for mixing and discharge. Finally, foam in an injection molding machine at 180°C, 10 MPa, and 10 min, then cool to obtain environmentally friendly and oil-resistant PVC slipper material.

[0030] Comparative Example 3: The difference between this comparative example and Example 1 is that carboxyl-terminated polyacrylonitrile is not added.

[0031] (1) Place 1.5 kg of nitrile rubber in a two-roll plasticizer for plasticizing, then add 8.5 kg of polyvinyl chloride, 3 kg of plasticizer dioctyl terephthalate, 200 g of GMA-grafted CPE, 300 g of calcium-zinc stabilizer, 160 g of filler zinc oxide, 70 g of stearic acid, 30 g of zinc stearate, and 120 g of antioxidant 4100NA. Mix at 100°C for 15 min, then add 500 g of foaming agent azodicarbonamide and 20 g of crosslinking agent dicumyl peroxide for mixing and discharge. Finally, foam in an injection molding machine at 180°C, 10 MPa, and 10 min, then cool to obtain environmentally friendly and oil-resistant PVC slipper material.

[0032] Comparative Example 4: The difference between this comparative example and Example 1 is that chlorinated polyethylene is used instead of GMA grafted CPE.

[0033] (1) Place 1.5 kg of nitrile rubber in a two-roll plasticizer for plasticizing, then add 8.5 kg of polyvinyl chloride, 3 kg of plasticizer dioctyl terephthalate, 200 g of chlorinated polyethylene, 180 g of carboxyl-terminated polyacrylonitrile, 300 g of calcium zinc stabilizer, 160 g of filler zinc oxide, 70 g of stearic acid, 30 g of zinc stearate, and 120 g of antioxidant 4100NA. Mix at 100°C for 15 min, then add 500 g of foaming agent azodicarbonamide and 20 g of crosslinking agent dicumyl peroxide for mixing and discharge. Finally, foam in an injection molding machine at 180°C, 10 MPa, and 10 min, then cool to obtain environmentally friendly and oil-resistant PVC slipper material.

[0034] Comparative Example 5: The difference between this comparative example and Example 1 is that polyacrylonitrile is used instead of carboxyl-terminated polyacrylonitrile.

[0035] (1) Add 400 mL of N,N-dimethylformamide, 100 g of acrylonitrile and 0.9 g of azobisisobutyronitrile to the reaction vessel, heat to 70 °C in a nitrogen atmosphere and react for 3 h. Dilute the solution with ethanol, filter and wash with ethanol, and dry to obtain polyacrylonitrile.

[0036] (2) Place 1.5 kg of nitrile rubber in a two-roll plasticizer for plasticizing, then add 8.5 kg of polyvinyl chloride, 3 kg of plasticizer dioctyl terephthalate, 200 g of GMA-grafted CPE, 180 g of polyacrylonitrile, 300 g of calcium-zinc stabilizer, 160 g of filler zinc oxide, 70 g of stearic acid, 30 g of zinc stearate, and 120 g of antioxidant 4100NA. Mix at 100°C for 15 min, then add 500 g of foaming agent azodicarbonamide and 20 g of crosslinking agent dicumyl peroxide for mixing and discharge. Finally, foam in an injection molding machine at 180°C, 10 MPa, and 10 min, then cool to obtain environmentally friendly and oil-resistant PVC slipper material.

[0037] A 20cm×8cm×1cm sample of PVC slipper material was prepared, dried, weighed, and then immersed in gasoline for 72 hours. After removal, the sample was hung for 30 minutes to drain and wipe off any residual gasoline. The sample was then weighed again, and the oil absorption rate W was calculated. W = (m - m0) / m0. The lower the oil absorption rate, the better the oil absorption and oil resistance.

[0038] The tensile properties of the slipper material were tested according to the national standard GB / T 6344-2008. The tear strength was tested according to the national standard GB / T10808-2006.

[0039] Table 1 Performance Tests of PVC Slipper Materials

[0040]

[0041] After testing, compared with Comparative Example 1, the PVC slipper materials of Examples 1-3, which incorporate GMA-grafted CPE and carboxyl-terminated polyacrylonitrile, showed that during high-temperature mixing, the epoxy groups of the GMA-grafted CPE side chains and the carboxyl groups of the polyacrylonitrile side chains underwent ring-opening initiation, thereby introducing the polyacrylonitrile molecular chains into the side chains of the chlorinated polyethylene (CPE) to form a polyacrylonitrile-CPE polymer. Due to the good compatibility between chlorinated polyethylene and polyvinyl chloride, and the similar polarity between the polyacrylonitrile molecular chains of the side chains and the polyacrylonitrile block molecular chains in nitrile rubber, the polyacrylonitrile-grafted CPE acts as a compatibilizer, further improving the compatibility between polyvinyl chloride and nitrile rubber. This results in PVC slipper materials with higher tensile properties and tear strength, as well as low oil absorption and excellent oil resistance.

[0042] Comparative Example 2 did not include GMA-grafted CPE. The carboxyl-terminated polyacrylonitrile had poor compatibility with polyvinyl chloride, which could not further improve the compatibility between polyvinyl chloride and nitrile rubber, and could not effectively improve the mechanical properties such as tear strength of PVC slipper material.

[0043] Comparative Example 3 did not include carboxyl-terminated polyacrylonitrile. The compatibility between GMA-grafted CPE and nitrile rubber was poor, which could not further improve the compatibility between polyvinyl chloride and nitrile rubber, and could not effectively improve the mechanical properties such as tear strength of PVC slipper material.

[0044] Comparative Example 4's chlorinated polyethylene does not contain epoxy groups, cannot react with carboxyl-terminated nitrile rubber, and does not form a polyacrylonitrile-CPE polymer. Therefore, it cannot further improve the compatibility between polyvinyl chloride and nitrile rubber, and cannot effectively improve the mechanical properties of PVC slipper materials such as tear strength.

[0045] Comparative Example 5, which contains no carboxyl group, cannot react with the epoxy groups of GMA-grafted CPE, and does not form a polyacrylonitrile-CPE polymer. Therefore, it cannot further improve the compatibility between polyvinyl chloride and nitrile rubber, and cannot effectively improve the mechanical properties of PVC slipper materials such as tear strength.

Claims

1. An environmentally friendly, oil-resistant PVC slipper material, characterized in that, By weight, the PVC slipper material comprises 70-85 parts polyvinyl chloride, 15-30 parts nitrile rubber, 23-30 parts plasticizer, 2-3.5 parts GMA-grafted CPE, 1.8-3 parts carboxyl-terminated polyacrylonitrile, 2.2-3 parts heat stabilizer, 3-5 parts foaming agent, 0.2-0.3 parts crosslinking agent, 1.3-2 parts filler, 0.8-1.3 parts additives, and 1.2-1.6 parts antioxidant.

2. The environmentally friendly, oil-resistant PVC slipper material according to claim 1, characterized in that, The plasticizer is dioctyl terephthalate, and the heat stabilizer is calcium-zinc stabilizer.

3. The environmentally friendly, oil-resistant PVC slipper material according to claim 1, characterized in that, The foaming agent is azodicarbonamide, and the crosslinking agent is dicumyl peroxide.

4. The environmentally friendly, oil-resistant PVC slipper material according to claim 1, characterized in that, The filler is zinc oxide, and the antioxidant is antioxidant 4100NA.

5. The environmentally friendly, oil-resistant PVC slipper material according to claim 1, characterized in that, The additive is any one or a combination of stearic acid and zinc stearate.

6. The environmentally friendly, oil-resistant PVC slipper material according to claim 1, characterized in that, The preparation process of GMA-grafted CPE is as follows: chlorinated polyethylene, glycidyl methacrylate, and dicumyl peroxide are added to a torque rheometer and melt-grafted at 170-175℃ for 6-10 min. After cooling and discharge, the product is added to xylene, heated under reflux, filtered, and then extracted with acetone in a Soxhlet extractor to obtain GMA-grafted CPE.

7. The environmentally friendly, oil-resistant PVC slipper material according to claim 6, characterized in that, By weight, the amount of chlorinated polyethylene is 100 parts, glycidyl methacrylate is 2-5 parts, and dicumyl peroxide is 0.3-0.6 parts.

8. The environmentally friendly, oil-resistant PVC slipper material according to claim 1, characterized in that, The preparation process of the carboxyl-terminated polyacrylonitrile is as follows: N,N-dimethylformamide, acrylonitrile, S,S'-bis(α,α'-methyl-α"-acetic acid) trithiocarbonate and azobisisobutyronitrile are added to a reaction vessel, heated to 65-75℃ in a nitrogen atmosphere, and reacted for 12-18 hours. Ethanol is added to dilute the solution, filtered, washed with ethanol, and dried to obtain carboxyl-terminated polyacrylonitrile.

9. The environmentally friendly, oil-resistant PVC slipper material according to claim 8, characterized in that, By weight, the amount of acrylonitrile is 100 parts, S,S'-bis(α,α'-methyl-α"-acetic acid) trithiocarbonate is 2.2-3.5 parts, and azobisisobutyronitrile is 0.22-0.3 parts.

10. A preparation process for an environmentally friendly, oil-resistant PVC slipper material as described in any one of claims 1-9, characterized in that, The preparation process is as follows: Nitrile rubber is placed in a two-roller plasticizer for plasticizing, and then polyvinyl chloride, plasticizer, GMA-grafted CPE, carboxyl-terminated polyacrylonitrile, heat stabilizer, filler, additives, and antioxidant are added. The mixture is then mixed at 100-110℃ for 10-15 minutes. Foaming agent and crosslinking agent are added and the mixture is further mixed and discharged. Finally, the mixture is foamed in an injection molding machine at a temperature of 180-210℃, a pressure of 10-15MPa, and a time of 8-10 minutes. After cooling, environmentally friendly and oil-resistant PVC slipper material is obtained.

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