Polyvinyl chloride thermoplastic elastomer material and method for producing the same

Abstract

This invention discloses a polyvinyl chloride thermoplastic elastomer material and its preparation process. By adjusting the use of polyvinyl chloride with different degrees of polymerization, adjusting the amount of plasticizer, and selecting nitrile rubber as the raw material, the properties such as acid resistance, alkali resistance, oil resistance, cold resistance, resilience, and tensile strength can be significantly improved. At the same time, by adding an appropriate amount of waste nitrile rubber powder modified by Sphingosine Monospora to the blend, the overall performance can be maintained while significantly reducing costs. This product has high economic benefits.

Description

Technical Field

[0001] This invention relates to a polymer material and its preparation method, and more specifically to a polyvinyl chloride thermoplastic elastomer material and its preparation method. Background Technology

[0002] Polyvinyl chloride (PVC) thermoplastic elastomers, along with polyolefin and polystyrene thermoplastic elastomers, together occupy a large share of the thermoplastic elastomer (TPE) market. Because PVC thermoplastic elastomers combine the reprocessability of thermoplastics with the high elasticity of rubber and other physical and mechanical properties, while also being recyclable, they have grown rapidly as a new type of polymer material used as a substitute for soft polymers and vulcanized rubber, and have formed a large market size.

[0003] Currently, there are many types of conventional polyvinyl chloride elastomer materials, and their preparation methods vary. However, in general, their formulations are all related to the performance of the product. Summary of the Invention

[0004] One of the objectives of this invention is to provide a highly elastic polyvinyl chloride thermoplastic elastomer material.

[0005] This invention is implemented as follows:

[0006] A polyvinyl chloride thermoplastic elastomer material comprises 100 parts by weight of polyvinyl chloride with a degree of polymerization of 3000, 100 parts by weight of polyvinyl chloride with a degree of polymerization of 1500-2000, 70-90 parts by weight of polyvinyl chloride with a degree of polymerization of 800-1000, 40-60 parts by weight of nitrile rubber, 20-40 parts by weight of waste nitrile rubber powder modified by Sphingospora, 200-250 parts by weight of plasticizer, 2-8 parts by weight of heat stabilizer, 0.1-1 parts by weight of lubricant, 1-5 parts by weight of processing aid, 0.1-1 parts by weight of antioxidant, and 5-15 parts by weight of filler, wherein the particle size of the nitrile rubber powder modified by Sphingospora is 20 micrometers-400 micrometers.

[0007] The particle size of the nitrile rubber powder modified by Sphingosine Monospora is 20 micrometers to 400 micrometers. The selection of the particle size of the rubber powder is closely related to the modification effect of the microorganism. During the research of this patent, it was found that when the particle size of the nitrile rubber powder is between 20 micrometers and 400 micrometers, the modification effect of Sphingosine Monospora is better, and the mechanical properties of the modified product are more likely to meet the product requirements.

[0008] The plasticizer is one or more of dioctyl phthalate, dioctyl adipate, trioctyl phosphate, and n-butyl stearate.

[0009] Nitrile rubber is used as a high-elasticity modifier, resulting in products with good resilience and good tensile strength.

[0010] A further proposed solution is that the heat stabilizer is at least one of the following: composite lead salt stabilizer, calcium-zinc stabilizer, calcium stearate, barium stearate, rare earth composite stabilizer, and epoxidized soybean oil. Heat stabilizers are additives that improve the thermal stability of PVC. Their function is to prevent or inhibit the degradation of PVC during the production of special materials, while maintaining sufficient thermal stability and extending the service life of the finished product.

[0011] A further option is that the lubricant is one or more of stearic acid, methylene bis-stearamide, glyceryl ester, oxidized polyethylene, and polyethylene wax. The lubricant can ensure that the melt viscosity of the material is reduced and prevent the material from adhering to the processing equipment or mold.

[0012] A further option is that the processing aid is at least one of acrylate resins, MBS resins, ethylene-vinyl acetate copolymer (EVA), and AMS (an oligomer of α-methylstyrene).

[0013] A further proposed solution is that the antioxidant is any one or more of phenolic antioxidants, amine antioxidants, phosphite antioxidants, and sulfur-containing ester antioxidants. The function of antioxidants is to capture free radicals formed during PVC processing or use due to heat or ultraviolet radiation, thus ensuring the material's lifespan.

[0014] A further option is that the filler is one or more of the following: activated calcium carbonate, talc, kaolin, and mica powder.

[0015] A further method is as follows: the preparation method of the sphingosine monospora modified waste nitrile rubber powder includes the following steps: the waste nitrile rubber powder is detoxified and sterilized with 75% ethanol by mass percentage, and sterilized at 121°C for 25 min in a fermentation medium; after sterilization, sphingosine monospora is inoculated into a desulfurization tank, and the sphingosine monospora and waste nitrile rubber powder are co-cultured and desulfurized in the fermentation medium; after the culture is completed, the waste nitrile rubber powder is collected, and washed and dried under stirring conditions to obtain sphingosine monospora modified nitrile rubber powder.

[0016] A further formulation is as follows: the culture medium consists of: NH4Cl: 0.5g, K2HPO4·3H2O: 1.3g, KH2PO4: 1.0g, MgSO4·7H2O: 0.18g, CaCl2: 0.01g; Na2S2O3·5H2O: 6g, FeS2O3·7H2O: 0.02g, peptone: 1.2g, and deionized water: 1000mL.

[0017] A further proposed approach is to co-culture *Sphingosine Monospora* and waste nitrile rubber powder in a fermentation medium for 30 days to desulfurize them.

[0018] The high-elasticity PVC thermoplastic elastomer material of this invention uses high-polymerization-degree polyvinyl chloride as its base resin. In addition to the general properties of polyvinyl chloride resin, this material also has good rubber elasticity (compression set, elongation set, resilience, etc.) and mechanical strength. Unlike other TPEs, by adjusting the use of polyvinyl chloride with different polymerization degrees, adjusting the amount of plasticizer, and selecting nitrile rubber as the raw material, the properties such as acid resistance, alkali resistance, oil resistance, cold resistance, resilience, and tensile strength can be significantly improved. At the same time, by adding an appropriate amount of waste nitrile rubber powder modified by Sphingosine Monospora to the blend, the overall good performance can be maintained while significantly reducing costs. This product has high economic benefits.

[0019] In the formulation design process, by selecting three different PVC resins with high, medium and low polymerization degrees, the crosslinking performance between PVC resin and nitrile rubber and waste nitrile rubber powder modified by Sphingosine Monospora is significantly improved. In particular, the use of medium and low polymerization degree PVC can significantly increase the mechanical properties of the material, such as elongation at break, while increasing the crosslinking performance. This invention creatively proposes a high-elasticity PVC thermoplastic elastomer material with excellent performance and low cost.

[0020] This invention also provides a method for preparing the PVC thermoplastic elastomer material, including the steps of batching, kneading, extrusion, and granulation, wherein: (1) Kneading: First, add polyvinyl chloride with a degree of polymerization of 3000, polyvinyl chloride with a degree of polymerization of 1500-2000, and 20% polyvinyl chloride with a degree of polymerization of 800-1000 and knead at high speed at 110°C for 5-10 minutes. Then, add 80% polyvinyl chloride with a degree of polymerization of 800-1000, plasticizer, and stabilizer and knead at high speed for 5-10 minutes. Then, switch to medium-speed kneading at 130-150°C for 2-10 minutes. Then, switch to slow-speed kneading, add lubricant and filler and knead for 1-10 minutes. Then, put it into a cooler to cool the temperature to 60-80°C. Add nitrile rubber and sphingosine monospora modified nitrile rubber powder and knead in the cooler for 1-10 minutes and then discharge.

[0021] (2) Extrusion: The mixture kneaded by the cooler is extruded through the extruder. The temperature of the first stage of the extruder is set to 135-155℃, the second stage to 139-159℃, the third stage to 150-170℃, the fourth stage to 155-175℃, the die head temperature to 150-160℃, and the extruder speed to 20-50 rpm.

[0022] A further improvement is that the extruder is a conical twin-screw extruder.

[0023] The PVC thermoplastic elastomer material prepared by this invention has the following characteristics: its tensile strength is significantly higher than that of general PVC thermoplastic elastomers; its elongation at break is higher; its heat distortion rate and low-temperature impact embrittlement temperature are lower; it has excellent heat aging resistance, acid resistance, alkali resistance, oil resistance, and cold resistance; it has excellent processing performance and appearance; and its preparation cost is significantly lower than that of general PVC thermoplastic elastomer materials. Detailed Implementation

[0024] The specific implementation methods of this technical solution will be further described in detail below.

[0025]

Example 1

[0026] 100 parts by weight of polyvinyl chloride (PVC) with a degree of polymerization of 3000, 100 parts by weight of PVC with a degree of polymerization of 1800, and 16 parts by weight of PVC with a degree of polymerization of 1000 were kneaded at high speed for 8 minutes at 110°C. Then, 64 parts by weight of PVC with a degree of polymerization of 1000, 20 parts by weight of dioctyl phthalate (a plasticizer), and 5 parts by weight of a composite lead salt stabilizer were added and kneaded at high speed for 6 minutes. After that, the kneading was switched to medium speed at 140°C for 5 minutes, and then switched to slow speed kneading. 0.4 parts by weight of stearic acid was added as a lubricant. (1) Knead the agent and 8 parts by weight of talc filler for 2 minutes, then put them into a cooler to cool to 70°C. Add 50 parts by weight of nitrile rubber and 30 parts by weight of waste nitrile rubber powder modified by sphingosine monosporus (nitrile rubber powder with a particle size of 20 microns) and knead in the cooler for 2 minutes before discharging. (2) Extrusion: The mixture kneaded in the cooler is extruded through an extruder. The temperature of the first section of the extruder is set to 145°C, the second section to 149°C, the third section to 160°C, the fourth section to 165°C, the die head temperature to 152°C, and the extruder speed to 31 rpm.

[0027] Comparative Example 1: Only 280 parts by weight of PVC with a polymer degree of 3000 were used, and all other conditions were the same.

[0028] Table 1 Properties of High-Elasticity PVC Thermoplastic Elastomer Materials

[0029] Tensile strength Mpa 17.5 11 Elongation at break % 392 293 Heat distortion % 30 48 Low temperature impact embrittlement temperature ℃ -41 -35

[0030]

Example 2

[0031] 100 parts by weight of polyvinyl chloride (PVC) with a degree of polymerization of 3000, 100 parts by weight of PVC with a degree of polymerization of 1800, and 16 parts by weight of PVC with a degree of polymerization of 1000 were kneaded at high speed for 8 minutes at 110°C. Then, 64 parts by weight of PVC with a degree of polymerization of 800, 20 parts by weight of dioctyl phthalate (a plasticizer), and 5 parts by weight of a composite lead salt stabilizer were added and kneaded at high speed for 6 minutes. After that, the kneading was switched to medium speed at 140°C for 5 minutes, and then switched to slow speed kneading. 0.4 parts by weight of stearic acid lubricant was added. Knead with 8 parts by weight of talc filler for 2 minutes, then put into a cooler to cool to 70°C, add 50 parts by weight of nitrile rubber and 30 parts by weight of waste nitrile rubber powder modified by sphingosine monosporus (nitrile rubber powder particle size is 400 micrometers) and knead in the cooler for 2 minutes before discharging; (2) Extrusion: The mixture kneaded by the cooler is extruded through an extruder. The temperature of the first stage of the extruder is set to 145°C, the second stage to 149°C, the third stage to 160°C, the fourth stage to 165°C, the die head temperature to 152°C, and the extruder speed to 31 rpm.

[0032] Comparative Example 2: Only 280 parts by weight of PVC with a polymer degree of 3000 were used, with other conditions remaining the same.

[0033] Table 2 Properties of High-Elasticity PVC Thermoplastic Elastomer Materials

[0034] Tensile strength Mpa 15 9 Elongation at break % 367 288 Heat distortion % 41 50 Low temperature impact embrittlement temperature ℃ -38 -35

[0035] The foregoing has shown and described the basic principles, main features, and advantages of this technical solution. Those skilled in the art should understand that this technical solution is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this technical solution. Various changes and modifications can be made to this technical solution without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed technical solution. The scope of protection of this technical solution is defined by the appended claims and their equivalents.

Claims

1. A process for the preparation of a polyvinyl chloride thermoplastic elastomer material, characterized in that: The polyvinyl chloride thermoplastic elastomer comprises 100 parts by weight of polyvinyl chloride with a degree of polymerization of 3000, 100 parts by weight of polyvinyl chloride with a degree of polymerization of 1800, 70-90 parts by weight of polyvinyl chloride with a degree of polymerization of 1000, 40-60 parts by weight of nitrile rubber, 20-40 parts by weight of waste nitrile rubber powder modified by Sphingospora monoporum, 20 parts by weight of plasticizer, 2-8 parts by weight of heat stabilizer, 0.1-1 parts by weight of lubricant, 1-5 parts by weight of processing aid, 0.1-1 parts by weight of antioxidant, and 5-15 parts by weight of filler. The particle size of the sphingosine monosporus modified nitrile rubber powder is 20 micrometers-400 micrometers; The preparation method of the sphingosine monospora modified nitrile rubber powder includes the following steps: waste nitrile rubber powder is detoxified and sterilized with 75% (w / w) ethanol, and sterilized at 121°C for 25 min in a fermentation medium; after sterilization, sphingosine monospora is inoculated into a desulfurization tank, and the sphingosine monospora and waste nitrile rubber powder are co-cultured for desulfurization in the fermentation medium; after the culture is completed, the waste nitrile rubber powder is collected, washed and dried under stirring conditions to obtain sphingosine monospora modified nitrile rubber powder; the co-culture desulfurization time of sphingosine monospora and waste nitrile rubber powder in the fermentation medium is 30 days; The preparation method of the polyvinyl chloride thermoplastic elastomer material includes the steps of batching, kneading, extrusion, and granulation, wherein: (1) Kneading: First, add polyvinyl chloride with a degree of polymerization of 3000, polyvinyl chloride with a degree of polymerization of 1800, and 20% polyvinyl chloride with a degree of polymerization of 1000 and knead at high speed for 5-10 minutes at 110°C. Then add 80% polyvinyl chloride with a degree of polymerization of 1000, plasticizer, and stabilizer and knead at high speed for 5-10 minutes. Then switch to medium speed kneading at 130-150°C for 2-10 minutes. Then switch to slow speed kneading, add lubricant and filler and knead for 1-10 minutes. After that, put it into a cooler to cool the temperature to 60-80°C. Add nitrile rubber and sphingosine monosporus modified nitrile rubber powder and knead in the cooler for 1-10 minutes and then discharge. (2) Extrusion: The mixture kneaded by the cooler is extruded through the extruder. The temperature of the first stage of the extruder is set to 135-155℃, the second stage to 139-159℃, the third stage to 150-170℃, the fourth stage to 155-175℃, the die head temperature to 150-160℃, and the extruder speed to 20-50 rpm.

2. The method of claim 1, wherein: The heat stabilizer is one or more of the following: composite lead salt stabilizer, calcium-zinc stabilizer, calcium stearate, barium stearate, rare earth composite stabilizer, and epoxidized soybean oil.

3. The method of claim 1, wherein: The lubricant is one or more of stearic acid, methylene bis-stearamide, glyceryl ester, oxidized polyethylene, and polyethylene wax.

4. The preparation method according to claim 1, characterized in that: The processing aid is one or more of acrylate resins, MBS resins, ethylene vinyl acetate copolymer EVA, and AMS (α-methylstyrene oligomers).

5. The method of claim 1, wherein: The antioxidant is any one or more of phenolic antioxidants, amine antioxidants, phosphite antioxidants, and sulfur-containing ester antioxidants.

6. The method of claim 1, wherein: The filler is one or more of active calcium carbonate, talcum powder, kaolin, mica powder.

7. The method of claim 1, wherein: The extruder is a conical twin-screw extruder.