High molecular weight polyvinyl chloride (HPVC) and cross-linked polyvinyl chloride (CLPVC)
DATE：2023/1/10 8:35:26 / READ： / SOURCE：This station
2.3.5 High molecular weight polyvinyl chloride
At present, there is no unified national standard for high molecular weight polyvinyl chloride (HPVC) resin. Table 2-75 shows the technical indicators of P-2500 type high polymerization degree PVC produced by Beijing Chemical Second Co., Ltd. for reference in selection and application.
2.3.5.1 Performance characteristics
High molecular weight PVC is a white powdery resin with a degree of polymerization in the range of 2000~3000. Compared with suspension PVC (degree of polymerization in the range of 500~1500), its products have higher mechanical properties such as tensile, bending and impact, and also have better fatigue resistance, wear resistance, cold resistance and heat resistance, and a wide range of temperature in application; The resin absorption plasticizer has good performance, and the products made by adding a large proportion of plasticizer have rubber elasticity. However, the processing performance is slightly worse than that of suspension PVC.
2.3.5.2 Forming method and purpose
High molecular weight polyvinyl chloride resin is generally only used for plasticizing processing, and products can be formed by extrusion molding, calendering and blow molding. It is mainly used to make soft products used in special occasions such as resistance to wear and fatigue. Such as wires and cables for high temperature (105 ℃), all-plastic flame-retardant transport belts, water hoses, hoses, sealing washers, electrical covers, floor tiles, radiation-resistant sealing materials, heat insulating gloves, high-strength films, high-grade soles, automotive lining accessories and artificial leather, etc.
2.3.6.1 Preparation method of cross-linked PVC
Cross-linked PVC can be prepared by radiation crosslinking and chemical crosslinking. This article only introduces the production method of cross-linked wires and cables with radiation using PVC resin as the main raw material.
(1) The radiation crosslinking method adds a certain proportion of multi-functional monomers (such as glyceryl trimethylacrylate, glyceryl triacrylate, etc.) and other additives to the PVC (suspension PVC) resin according to the formula requirements, but it should be noted that the initiator should not be added. After accurate measurement, mix them together, and then mix them evenly; The raw materials are plasticized by the extruder, extruded from the mold, processed into products (wires and cables, tubes or other profiles), protected under vacuum or nitrogen conditions, and irradiated by electron rays, r rays, etc., to form a cross-linked structure.
(2) Production process of radiation cross-linked PVC production process sequence is: PVC - electronic ray other additives - multi-functional monomer - → metering and mixing evenly → processed products>radiation cross-linked → cross-linked PVC
Product Table 2-76 lists the performance parameters in the enterprise standard Q/XGY 025-92 of PVC for radiation cross-linked wires and cables of China Blue Chenguang Chemical Research Institute ZJFL-105. Table 2-77 is the enterprise standard of 80 ℃ radiation cross-linked PVC insulation material of Shanghai Cable Research Institute, which is used as reference for selection of supply time.
2.3.6.2 Forming method and purpose
The radiation cross-linked PVC resin is mixed with other additives according to the formula requirements, and then the suspension method is used to dye the ethylene to form the product. For example, cross linked PVC wires and cables are extruded into current products by extruder.
Compared with the wire and cable made of ordinary PVC resin, the radiation cross-linked PVC wire and cable is a kind of wire and cable with high strength, heat resistance (up to 105 ℃) and wear resistance. Radiated cross-linked PVC wires and cables can be used in the internal connecting lines of dryers, bakeries, hair curlers, electric water bottles, rice cookers, etc., transformer outgoing lines, motor outgoing lines, lighting equipment wiring, internal wiring of air conditioners, high voltage outgoing lines of color television, internal wiring of small and delicate appliances such as micro-recorders, cameras and cameras. Because of its excellent mechanical properties, abrasion resistance and chemical solvent resistance, this kind of cross-linked PVC wire and cable is also widely used in automobile, aviation, aerospace, weapons, ships and other fields.
At present, there is no unified national standard for high molecular weight polyvinyl chloride (HPVC) resin. Table 2-75 shows the technical indicators of P-2500 type high polymerization degree PVC produced by Beijing Chemical Second Co., Ltd. for reference in selection and application.
2.3.5.1 Performance characteristics
High molecular weight PVC is a white powdery resin with a degree of polymerization in the range of 2000~3000. Compared with suspension PVC (degree of polymerization in the range of 500~1500), its products have higher mechanical properties such as tensile, bending and impact, and also have better fatigue resistance, wear resistance, cold resistance and heat resistance, and a wide range of temperature in application; The resin absorption plasticizer has good performance, and the products made by adding a large proportion of plasticizer have rubber elasticity. However, the processing performance is slightly worse than that of suspension PVC.
2.3.5.2 Forming method and purpose
High molecular weight polyvinyl chloride resin is generally only used for plasticizing processing, and products can be formed by extrusion molding, calendering and blow molding. It is mainly used to make soft products used in special occasions such as resistance to wear and fatigue. Such as wires and cables for high temperature (105 ℃), all-plastic flame-retardant transport belts, water hoses, hoses, sealing washers, electrical covers, floor tiles, radiation-resistant sealing materials, heat insulating gloves, high-strength films, high-grade soles, automotive lining accessories and artificial leather, etc.
2.3.6 Crosslinked PVC
Cross-linked polyvinyl chloride (CLPVC) can also be called polyvinyl chloride or thermosetting polyvinyl chloride.2.3.6.1 Preparation method of cross-linked PVC
Cross-linked PVC can be prepared by radiation crosslinking and chemical crosslinking. This article only introduces the production method of cross-linked wires and cables with radiation using PVC resin as the main raw material.
(1) The radiation crosslinking method adds a certain proportion of multi-functional monomers (such as glyceryl trimethylacrylate, glyceryl triacrylate, etc.) and other additives to the PVC (suspension PVC) resin according to the formula requirements, but it should be noted that the initiator should not be added. After accurate measurement, mix them together, and then mix them evenly; The raw materials are plasticized by the extruder, extruded from the mold, processed into products (wires and cables, tubes or other profiles), protected under vacuum or nitrogen conditions, and irradiated by electron rays, r rays, etc., to form a cross-linked structure.
(2) Production process of radiation cross-linked PVC production process sequence is: PVC - electronic ray other additives - multi-functional monomer - → metering and mixing evenly → processed products>radiation cross-linked → cross-linked PVC
Product Table 2-76 lists the performance parameters in the enterprise standard Q/XGY 025-92 of PVC for radiation cross-linked wires and cables of China Blue Chenguang Chemical Research Institute ZJFL-105. Table 2-77 is the enterprise standard of 80 ℃ radiation cross-linked PVC insulation material of Shanghai Cable Research Institute, which is used as reference for selection of supply time.
2.3.6.2 Forming method and purpose
The radiation cross-linked PVC resin is mixed with other additives according to the formula requirements, and then the suspension method is used to dye the ethylene to form the product. For example, cross linked PVC wires and cables are extruded into current products by extruder.
Compared with the wire and cable made of ordinary PVC resin, the radiation cross-linked PVC wire and cable is a kind of wire and cable with high strength, heat resistance (up to 105 ℃) and wear resistance. Radiated cross-linked PVC wires and cables can be used in the internal connecting lines of dryers, bakeries, hair curlers, electric water bottles, rice cookers, etc., transformer outgoing lines, motor outgoing lines, lighting equipment wiring, internal wiring of air conditioners, high voltage outgoing lines of color television, internal wiring of small and delicate appliances such as micro-recorders, cameras and cameras. Because of its excellent mechanical properties, abrasion resistance and chemical solvent resistance, this kind of cross-linked PVC wire and cable is also widely used in automobile, aviation, aerospace, weapons, ships and other fields.
Author：admin