Thermoplastic resins for wire and cable include polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), fluororesin, chlorinated polyether, and polyamide, among which PE, PVC, and PP are widely used. This article reviews the development status and development trend of these three kinds of cable materials at home and abroad.
1 Development Status and Development Trend of Cable Materials in the World In recent years, cable products in the world have continued to grow, with the fastest growing in the Americas. The output of cable products in North America is about 26% of the world's total output. The largest share of the world’s total cable production is the use of low-voltage cables and wires for the power industry, which account for about 36% of the total. Followed by high-voltage cables, accounting for about 28% of the total; around 20% of the total package; copper cable communication cables for outdoor use, accounting for about 9% of the total; computer cables and Other types of buildings. The internal communication cable accounts for about 7% of the total. Judging from the output value of cable production, fiber optic cables and computer cables account for approximately 25.4% of the total, of which optical fiber cables account for approximately 8.9% of the total.
From the point of view of growth, the fastest growth rate is in fiber optic cable: According to the research report of Cahners In-Star Group, the outlook for fiber optic cable is very promising. Before 2005, it will increase at an average annual growth rate of 23%. Second only to the optical fiber cable is the computer cable and the communication cable for indoor installation, and the power cable maintains a slight and steadily increasing trend. The world wire and cable production statistics are shown in Table 1 [1].
With the development of the world cable industry, the demand for various cable materials corresponding to the above cables is also increasing.
1.1 PE Cables PEs were used in telecommunication cables in foreign countries as early as the 1940s. In the mid to late 1990s, PE cables have occupied an important position in PE products. In recent years. With the increase of environmental protection calls, PE is gradually replacing PVC in the world, making the consumption of PE cable resin increase year by year.
1.1.1 PE High-speed Extrusion Communication Cable Material At present, high-density polyethylene (HDPE) or medium-density polyethylene (MDPE) is commonly used as communication insulation material in the world. HDPE has good mechanical strength and electrical properties, especially high toughness, and fully meets the requirements for the use of insulating materials. Since the mid-1970s, the insulation layer of the local cable has been mostly used HDPE [2].
1.1.2 Cross-linked PE cable material The power cable is continuously developing in the direction of cross-linked PE. At present, internationally, cross-linked PEs tend to be used from 1 kV low-pressure cables, 6.35 kV medium-low-pressure cables to 110 kV high-pressure cables. Internationally cross-linked PE production technology is mainly divided into three categories: radiation cross-linking mainly produces electrical equipment with electrical cables; silane cross-linking with silane as a cross-linking agent, under the action of the catalyst to make PE cross-linked; chemical cross-linked with low-density polyethylene (LDPE) is a base material, organic peroxide is a cross-linking agent, and is suitable for cables used under conditions of high temperature, high voltage, high frequency, etc., and can produce 6-35 kV, 35.110 kV medium and high voltage cables, aviation cables, and control cables. And so on, its production technology is mainly invented and promoted by the United States GE company.
1.1.3 Flame-retardant PE cable materials In the early 1980s, low-smoke halogen-free flame retardant cable materials were developed abroad. By the late 1980s, the second generation of halogen-free flame retardant plastics for wire and cable had been developed. Compared with the first generation of products, the second-generation non-halogen flame-retardant plastics are not only improved in flame retardancy, smokeability, toxicity, corrosion performance, mechanical properties, and electrical properties, but also exhibit high-speed extrusion performance. feature.
Japan promulgates more than 50% of patents related to halogen-free flame-retardant cable materials each year. Most of these patents belong to Hitachi Cable Co., Ltd., Japan Union Carbide Corporation, and Fujikura, Sumitomo, Daejoku, and other wire companies. This type of patent attempts to solve the central problem of halogen-free flame-retardant cable materials by using different methods, that is, to overcome the contradiction between the flame-retardant performance and other properties and to perform comprehensive balance of various properties; many other patents are devoted to the development of new compounding agents. Magnesium hydroxide is an important compounding agent. Has been patented in many countries, and recommended by many foreign authoritative literature 1.1.4 Shielded cable shielding cable material is used in the cable to protect the main insulation layer is not damaged semi-conductive composite materials. According to IEC 502, when the rated voltage is above 1.8/3.0 kV, and the cable insulated with PVC and ethylene propylene rubber has a rated voltage of 3.6/6.0 kV, the inner and outer semi-conductive shields must be used.
At present, many polyolefin manufacturers in the world have developed and produced special materials for semi-conductive shielding of cross-linked PE cables. Such as UCC, the United States, the main brands include HFDA-0590, HFDA-0585, HF. DA--08804;13 The word of the Ministry of Xing production company, the main brands are UBECV315, VBECV 319; British BP company. The main brands are HFDM 0595 (black), H315 ES (black), H310 ES (black).
1.2 PVC cable materials In the insulation and sheathing materials of wire and cable, PVC is cheaper, has excellent mechanical properties and is easy to process, making it a long-term use material for the wire and cable industry. Since the end of the 20th century, the environmental issues of PVC materials have been widely recognized. Some developed countries have proposed ordinances that restrict or completely prohibit the use of PVC cables. According to statistics, the amount of PVC used in the wire and cable industry in Western Europe was 44 lkt in 1994, accounting for 58% of the polymer used in the cable. In 2000, the total amount of PVC used in the cable industry in Western Europe was 398 kt. Accounting for 48% of the polymer used in the cable, the total volume and the share of the cable showed a downward trend. In recent years, the control and prohibition of the use of PVC materials has become a strong trend.
Although the use of halogen-free materials to replace PVC materials is increasing, but PVC itself can not be replaced in the short term advantages (such as low prices, good flame resistance, processing equipment, process is simple, a wide range of hardness adjustable, electrical insulation Good performance, oil resistance, chemical resistance, etc.) Therefore, it is not realistic to completely prohibit the use of PVC in the world in the short term [3].
1.3 PP cable PP is widely used in power cable overhead lines and electrical equipment cables because of its mechanical properties, electrical properties, abrasion resistance, and superior chemical resistance, especially oil resistance. The use of PP in foreign countries for the insulation of electric wires and cables began in the 1960s. By the late 1990s, the use of PP in the United States has reached more than 10 kt, which accounts for a significant portion of the total amount of PP. British BP, 13-word Hingchan, German Bayer and other companies all have PP cable grades, but the United States has developed the most PP wire and cable grades, and Profax SE 191 is the best. Due to the requirement of low temperature resistance and flexibility, PP for foreign cables is ethylene-propylene block copolymer.
2 China's cable material development status and development trend Since 2000, China's cable supply is in short supply, and some products even appear out of stock. There are nearly 5,000 wire and cable manufacturers in China. Due to the huge demand for wire and cable products due to the transformation of urban and rural power grids, the development of the western region, and the large-area upgrading and transformation of the Sanhe project and communication facilities. Therefore, from a period of time, cable materials have a wide market prospect in China. It is estimated that by 2005, the total amount of resin consumed for cable materials may increase to 270 kt [4].
2.1 PE cable materials China began production of PE cable materials in the 1980s, mainly used for communication cables and power cables. According to research, in 2000 China's domestic cable industry consumed about 140 kt of PE cable, including domestic material (64 kt), accounting for about 45%, imported materials accounted for 4 JD%, and general material substitution accounted for 15%; in 2001, China's domestic cable industry. The consumption of PE cable is about 180 kt, of which domestic production is 67 kt, the share is about 38%, imported material is 47%, and general-purpose material substitution is 15%[5].
2.1.1 Communications cable materials With the development of communications, domestically, approximately 12 million phones will be added each year, which requires 35 kt of insulation material for wire and cable and 4 JD kt for sheathing materials. Optical fiber cables require 7 kt of resin annually, and by the year 2000, the amount of sheathing material will increase by 10 times [6].
Communication cable insulation is mainly used HDPE. In China, 50% of the HDPE cable material market is occupied by imported materials. Mainly UCC's DGDK3364, DFDA 0610, DFDA 0580, DMD 3479, etc. [5,7]. Qilu Petrochemical has developed a special resin QHj01 for high-speed processing of communication cables. The product quality meets the requirements of the Ministry of Posts and Telecommunications, YD/T 76o-l995. The insulated core wire and cable products made of this insulating material comply with the Ministry of Posts and Telecommunications standard YD/T 322-l996.
LDPE sheathing material is the earliest sheath material used for local telephone cables. It is the earliest cable material produced in China and the largest output. The product is generally black and can be used for communication cables or power cables. In recent years, it has also been used for optical cables. Domestic black LDPE sheath material has the disadvantages of poor environmental stress resistance and poor processability in recent years, which is the focus of current domestic research.
The development of insulation and sheathing materials for linear low-density polyethylene (IJ.DPE) has improved processability [8]. LLDPE's electrical properties, mechanical properties and environmental stress crack resistance are higher than those of LDPE. It is suitable for insulating materials and sheathing materials of communication cables. In recent years, Qilu Petrochemical has adopted IJ. DPE is a basic material, research and development of LLDPE communication cable insulation material and sheath material, physical properties meet the requirements of the United States REA-200 standard, the performance of the cable meet the Ministry of Posts and Telecommunications YD322-1996 requirements, respectively, with the United States UCC's 1JDPE Insulation material DFDA 7540 and sheath material DFDA 6059 are equivalent and have high economic benefits.
With the continuous development of the cable industry in China, many new products have emerged in the cable industry in recent years. For example, Qilu Petrochemical has developed a PE foam cable insulation for communication cables, and foamed insulated core wires made from this special material. The cable complies with the YD/T 322-1996 standard of the Ministry of Posts and Telecommunications and the requirements of the cable manufacturer. The overall performance can be compared with the current international advanced product DGDA 3485. The company developed the PE physical foam insulation material for railway communication cables, using physical Foam insulation, with the maturity of physical foam insulation processing technology and market acceptance, physical foam insulation communication cables are replacing the solid insulated communication cables with increasing trend year by year. In addition, Shanghai Petrochemical Co., Ltd. uses the "North Star Twin Peak" PE process of Borealis to produce bimodal PE, which combines excellent physical properties, electrical properties and excellent processing performance. It is very suitable as a communication cable and optical cable. Sheath material [9].
2.1.2 Insulating materials for power cables [5]
Cross-linked PE is the main insulating material in China's power cable production. Low-voltage cables are mainly made of silane-crosslinked PE materials. The current situation is that supply exceeds demand. The annual production is about 5×104 km. A relatively large production company has the ability to produce 7 kt per year on one production line. Medium-voltage cable (10kv class) can be self-sufficient in the domestic use of cross-linkable materials. The annual consumption is approximately 20 30 kt. At present, all high-voltage cables can be imported with cross-linkable materials, and the usage amount is approximately 5-10 kt per year. China's current l10 kV cable demand is about 21dm/a, and ultra-clean insulation material is required to be about 5 kt. In addition, China's current demand for semi-conductive shielding material is about 5 kt. The demand for semi-conductive shielding material is l0 kt.
Power cable insulation materials generally use LDPE. At present, the domestic LDPE power cable special materials can only be used for cables below 35kV, the main products are 19E of Daqing Petrochemical Branch of PetroChina and 510-000, 535-000 of Maoming Petrochemical Ethylene Industry Company, DJ of Shanghai Petrochemical Company Limited. 200A, DJ 210 and so on. More than 35kV of insulation material, all rely on imports, mainly UCC and Borealis's 4201, Japan's Ministry of Industrial Co., Ltd.'s UBEC180; LDPE cable sheathing material Japan Ube Kogyo Co. UBEC 600V. In China, due to the lack of ultra-clean packaging of PE raw materials, and the insufficient degree of crosslinking of raw materials LJ and PE, it is unable to meet the requirements of high voltage levels [10].
2.1.3 Insulation materials for electrical equipment lines With the increasing awareness of environmental protection in the world, the use of flame-retardant cables has gradually increased in the construction of various types of projects. Power cables, control cables, signal cables, etc., all require flame retardance. In recent years, fire-fighting departments in some regions have been demanding the use of halogen-free flame-retardant materials, so low-smoke halogen-free materials are the direction of development, and their market demand is very promising. The current use of a relatively large amount of low-smoke halogen-free thermoplastic sheath material, a small amount of cross-linkable sheath material. In addition, there are some highly demanding projects where cable insulation requires the use of cross-linkable low-smoke, halogen-free materials.
At the end of 1980s, China has begun to develop low-smoke, low-halogen, low-acid, halogen-free flame-retardant cable material formulations and products. Some manufacturers have produced low-smoke, halogen-free flame-retardant cable materials, but most of them have mechanical properties and Poor processing performance and other issues. Currently used halogen-free flame-retardant cable materials are still dependent on imports to a certain extent [8]. Its domestic requirements are still the subject of domestic cable manufacturers. Halogen-free flame-retardant wire and cable is the key development direction of flame-retardant wire and cable in the future. It is estimated that the annual consumption will be about 2 kt in the near future, and it is expected that the demand in the domestic market will reach more than l5 kt in 2010.
2.1.4 Semi-conductive shielding materials Semi-conductive shielding materials are necessary supporting materials for medium and high voltage power cables. The semi-conductive shielding material used for high-voltage and ultra-high voltage cross-over cables in foreign countries has high requirements for indicators, and domestic technology is not used. Currently, it is dependent on imports. For the l0kV power cable shielding materials, the properties and processes of domestic materials are also not very satisfactory. The ratio of the amount of shielding material and insulating material inside and outside is approximately 4:1. It is estimated that the annual amount of shielding material used in our country is 20-30 kt.
2.2 PVC cable materials In China, PVC cable materials were developed earlier, with more varieties and models. Recently, due to the improvement of environmental protection requirements at home and abroad, the development of PVC cable materials in China has gradually declined. However, due to the low price of PVC cable materials, combined with various advantages such as excellent mechanical properties, China's PVC cable material has a certain future development prospects. The recent domestic development of new products mainly include: PVC oil-resistant material, matt material. Irradiation crosslinking PVC cable materials.
Although at present, PVC wire and cable will not be eliminated immediately in foreign countries, but this can not but arouse the domestic wire and cable industry attaches great importance, the domestic should focus on the study of non-lead PVC or the development of new halogen-free environmentally friendly wire and cable. Although environmental protection wire and cable will take a long time to replace PVC cables in China, this is a general trend. Some domestic high-end projects have already put forward requirements for this.
2.3 PP cable material PP cable material insulation material is widely used in oil well submersible pump cable insulation layer. China's submersible pump and cable production plant needs about 5 kt PP cable material each year, and in addition to some domestically-produced materials, a large amount of imported materials are also needed. The main imported material is Pro-Fax SE191 from Himomo, USA.
China began to develop PP wire and cable insulation in the early 1980s.
Beijing Yanshan Petrochemical Co., Ltd. first successfully developed 1336D and 1396D, and subsequently developed 1296D and 2496D, and later Qilu Petrochemical, Shanghai Chemical Plant, Lanzhou Chemical Research Institute and other units also carried out this work.
3 Suggestions a) At present, the demand for crosslinkable insulation materials for high voltage power cables in China is huge. Has a good technical and economic benefits, basically all imported, mainly because there is no domestic base resin. Therefore, it is recommended that China Petroleum & Chemical Corporation introduce foreign advanced technology to develop and produce ultra-clean PE insulation materials for high-voltage cables in order to speed up its localization process.
b) China's high-voltage and ultra-high voltage cross-linked cables used semi-conductive shielding materials and halogen-free flame-retardant cable sheathing materials are basically dependent on imports, and some cable materials (such as high-performance telecommunications cable insulation materials) are still occupied by imported materials to a certain extent . Should increase the development of these special materials. To meet the large demand of domestic and foreign markets.
c) In view of the special circumstances of PVC cable materials, such as oil-resistant materials, matt materials, radiation cross-linked cable materials, etc., there are still certain development prospects, and they should also be studied.
1 Development Status and Development Trend of Cable Materials in the World In recent years, cable products in the world have continued to grow, with the fastest growing in the Americas. The output of cable products in North America is about 26% of the world's total output. The largest share of the world’s total cable production is the use of low-voltage cables and wires for the power industry, which account for about 36% of the total. Followed by high-voltage cables, accounting for about 28% of the total; around 20% of the total package; copper cable communication cables for outdoor use, accounting for about 9% of the total; computer cables and Other types of buildings. The internal communication cable accounts for about 7% of the total. Judging from the output value of cable production, fiber optic cables and computer cables account for approximately 25.4% of the total, of which optical fiber cables account for approximately 8.9% of the total.
From the point of view of growth, the fastest growth rate is in fiber optic cable: According to the research report of Cahners In-Star Group, the outlook for fiber optic cable is very promising. Before 2005, it will increase at an average annual growth rate of 23%. Second only to the optical fiber cable is the computer cable and the communication cable for indoor installation, and the power cable maintains a slight and steadily increasing trend. The world wire and cable production statistics are shown in Table 1 [1].
With the development of the world cable industry, the demand for various cable materials corresponding to the above cables is also increasing.
1.1 PE Cables PEs were used in telecommunication cables in foreign countries as early as the 1940s. In the mid to late 1990s, PE cables have occupied an important position in PE products. In recent years. With the increase of environmental protection calls, PE is gradually replacing PVC in the world, making the consumption of PE cable resin increase year by year.
1.1.1 PE High-speed Extrusion Communication Cable Material At present, high-density polyethylene (HDPE) or medium-density polyethylene (MDPE) is commonly used as communication insulation material in the world. HDPE has good mechanical strength and electrical properties, especially high toughness, and fully meets the requirements for the use of insulating materials. Since the mid-1970s, the insulation layer of the local cable has been mostly used HDPE [2].
1.1.2 Cross-linked PE cable material The power cable is continuously developing in the direction of cross-linked PE. At present, internationally, cross-linked PEs tend to be used from 1 kV low-pressure cables, 6.35 kV medium-low-pressure cables to 110 kV high-pressure cables. Internationally cross-linked PE production technology is mainly divided into three categories: radiation cross-linking mainly produces electrical equipment with electrical cables; silane cross-linking with silane as a cross-linking agent, under the action of the catalyst to make PE cross-linked; chemical cross-linked with low-density polyethylene (LDPE) is a base material, organic peroxide is a cross-linking agent, and is suitable for cables used under conditions of high temperature, high voltage, high frequency, etc., and can produce 6-35 kV, 35.110 kV medium and high voltage cables, aviation cables, and control cables. And so on, its production technology is mainly invented and promoted by the United States GE company.
1.1.3 Flame-retardant PE cable materials In the early 1980s, low-smoke halogen-free flame retardant cable materials were developed abroad. By the late 1980s, the second generation of halogen-free flame retardant plastics for wire and cable had been developed. Compared with the first generation of products, the second-generation non-halogen flame-retardant plastics are not only improved in flame retardancy, smokeability, toxicity, corrosion performance, mechanical properties, and electrical properties, but also exhibit high-speed extrusion performance. feature.
Japan promulgates more than 50% of patents related to halogen-free flame-retardant cable materials each year. Most of these patents belong to Hitachi Cable Co., Ltd., Japan Union Carbide Corporation, and Fujikura, Sumitomo, Daejoku, and other wire companies. This type of patent attempts to solve the central problem of halogen-free flame-retardant cable materials by using different methods, that is, to overcome the contradiction between the flame-retardant performance and other properties and to perform comprehensive balance of various properties; many other patents are devoted to the development of new compounding agents. Magnesium hydroxide is an important compounding agent. Has been patented in many countries, and recommended by many foreign authoritative literature 1.1.4 Shielded cable shielding cable material is used in the cable to protect the main insulation layer is not damaged semi-conductive composite materials. According to IEC 502, when the rated voltage is above 1.8/3.0 kV, and the cable insulated with PVC and ethylene propylene rubber has a rated voltage of 3.6/6.0 kV, the inner and outer semi-conductive shields must be used.
At present, many polyolefin manufacturers in the world have developed and produced special materials for semi-conductive shielding of cross-linked PE cables. Such as UCC, the United States, the main brands include HFDA-0590, HFDA-0585, HF. DA--08804;13 The word of the Ministry of Xing production company, the main brands are UBECV315, VBECV 319; British BP company. The main brands are HFDM 0595 (black), H315 ES (black), H310 ES (black).
1.2 PVC cable materials In the insulation and sheathing materials of wire and cable, PVC is cheaper, has excellent mechanical properties and is easy to process, making it a long-term use material for the wire and cable industry. Since the end of the 20th century, the environmental issues of PVC materials have been widely recognized. Some developed countries have proposed ordinances that restrict or completely prohibit the use of PVC cables. According to statistics, the amount of PVC used in the wire and cable industry in Western Europe was 44 lkt in 1994, accounting for 58% of the polymer used in the cable. In 2000, the total amount of PVC used in the cable industry in Western Europe was 398 kt. Accounting for 48% of the polymer used in the cable, the total volume and the share of the cable showed a downward trend. In recent years, the control and prohibition of the use of PVC materials has become a strong trend.
Although the use of halogen-free materials to replace PVC materials is increasing, but PVC itself can not be replaced in the short term advantages (such as low prices, good flame resistance, processing equipment, process is simple, a wide range of hardness adjustable, electrical insulation Good performance, oil resistance, chemical resistance, etc.) Therefore, it is not realistic to completely prohibit the use of PVC in the world in the short term [3].
1.3 PP cable PP is widely used in power cable overhead lines and electrical equipment cables because of its mechanical properties, electrical properties, abrasion resistance, and superior chemical resistance, especially oil resistance. The use of PP in foreign countries for the insulation of electric wires and cables began in the 1960s. By the late 1990s, the use of PP in the United States has reached more than 10 kt, which accounts for a significant portion of the total amount of PP. British BP, 13-word Hingchan, German Bayer and other companies all have PP cable grades, but the United States has developed the most PP wire and cable grades, and Profax SE 191 is the best. Due to the requirement of low temperature resistance and flexibility, PP for foreign cables is ethylene-propylene block copolymer.
2 China's cable material development status and development trend Since 2000, China's cable supply is in short supply, and some products even appear out of stock. There are nearly 5,000 wire and cable manufacturers in China. Due to the huge demand for wire and cable products due to the transformation of urban and rural power grids, the development of the western region, and the large-area upgrading and transformation of the Sanhe project and communication facilities. Therefore, from a period of time, cable materials have a wide market prospect in China. It is estimated that by 2005, the total amount of resin consumed for cable materials may increase to 270 kt [4].
2.1 PE cable materials China began production of PE cable materials in the 1980s, mainly used for communication cables and power cables. According to research, in 2000 China's domestic cable industry consumed about 140 kt of PE cable, including domestic material (64 kt), accounting for about 45%, imported materials accounted for 4 JD%, and general material substitution accounted for 15%; in 2001, China's domestic cable industry. The consumption of PE cable is about 180 kt, of which domestic production is 67 kt, the share is about 38%, imported material is 47%, and general-purpose material substitution is 15%[5].
2.1.1 Communications cable materials With the development of communications, domestically, approximately 12 million phones will be added each year, which requires 35 kt of insulation material for wire and cable and 4 JD kt for sheathing materials. Optical fiber cables require 7 kt of resin annually, and by the year 2000, the amount of sheathing material will increase by 10 times [6].
Communication cable insulation is mainly used HDPE. In China, 50% of the HDPE cable material market is occupied by imported materials. Mainly UCC's DGDK3364, DFDA 0610, DFDA 0580, DMD 3479, etc. [5,7]. Qilu Petrochemical has developed a special resin QHj01 for high-speed processing of communication cables. The product quality meets the requirements of the Ministry of Posts and Telecommunications, YD/T 76o-l995. The insulated core wire and cable products made of this insulating material comply with the Ministry of Posts and Telecommunications standard YD/T 322-l996.
LDPE sheathing material is the earliest sheath material used for local telephone cables. It is the earliest cable material produced in China and the largest output. The product is generally black and can be used for communication cables or power cables. In recent years, it has also been used for optical cables. Domestic black LDPE sheath material has the disadvantages of poor environmental stress resistance and poor processability in recent years, which is the focus of current domestic research.
The development of insulation and sheathing materials for linear low-density polyethylene (IJ.DPE) has improved processability [8]. LLDPE's electrical properties, mechanical properties and environmental stress crack resistance are higher than those of LDPE. It is suitable for insulating materials and sheathing materials of communication cables. In recent years, Qilu Petrochemical has adopted IJ. DPE is a basic material, research and development of LLDPE communication cable insulation material and sheath material, physical properties meet the requirements of the United States REA-200 standard, the performance of the cable meet the Ministry of Posts and Telecommunications YD322-1996 requirements, respectively, with the United States UCC's 1JDPE Insulation material DFDA 7540 and sheath material DFDA 6059 are equivalent and have high economic benefits.
With the continuous development of the cable industry in China, many new products have emerged in the cable industry in recent years. For example, Qilu Petrochemical has developed a PE foam cable insulation for communication cables, and foamed insulated core wires made from this special material. The cable complies with the YD/T 322-1996 standard of the Ministry of Posts and Telecommunications and the requirements of the cable manufacturer. The overall performance can be compared with the current international advanced product DGDA 3485. The company developed the PE physical foam insulation material for railway communication cables, using physical Foam insulation, with the maturity of physical foam insulation processing technology and market acceptance, physical foam insulation communication cables are replacing the solid insulated communication cables with increasing trend year by year. In addition, Shanghai Petrochemical Co., Ltd. uses the "North Star Twin Peak" PE process of Borealis to produce bimodal PE, which combines excellent physical properties, electrical properties and excellent processing performance. It is very suitable as a communication cable and optical cable. Sheath material [9].
2.1.2 Insulating materials for power cables [5]
Cross-linked PE is the main insulating material in China's power cable production. Low-voltage cables are mainly made of silane-crosslinked PE materials. The current situation is that supply exceeds demand. The annual production is about 5×104 km. A relatively large production company has the ability to produce 7 kt per year on one production line. Medium-voltage cable (10kv class) can be self-sufficient in the domestic use of cross-linkable materials. The annual consumption is approximately 20 30 kt. At present, all high-voltage cables can be imported with cross-linkable materials, and the usage amount is approximately 5-10 kt per year. China's current l10 kV cable demand is about 21dm/a, and ultra-clean insulation material is required to be about 5 kt. In addition, China's current demand for semi-conductive shielding material is about 5 kt. The demand for semi-conductive shielding material is l0 kt.
Power cable insulation materials generally use LDPE. At present, the domestic LDPE power cable special materials can only be used for cables below 35kV, the main products are 19E of Daqing Petrochemical Branch of PetroChina and 510-000, 535-000 of Maoming Petrochemical Ethylene Industry Company, DJ of Shanghai Petrochemical Company Limited. 200A, DJ 210 and so on. More than 35kV of insulation material, all rely on imports, mainly UCC and Borealis's 4201, Japan's Ministry of Industrial Co., Ltd.'s UBEC180; LDPE cable sheathing material Japan Ube Kogyo Co. UBEC 600V. In China, due to the lack of ultra-clean packaging of PE raw materials, and the insufficient degree of crosslinking of raw materials LJ and PE, it is unable to meet the requirements of high voltage levels [10].
2.1.3 Insulation materials for electrical equipment lines With the increasing awareness of environmental protection in the world, the use of flame-retardant cables has gradually increased in the construction of various types of projects. Power cables, control cables, signal cables, etc., all require flame retardance. In recent years, fire-fighting departments in some regions have been demanding the use of halogen-free flame-retardant materials, so low-smoke halogen-free materials are the direction of development, and their market demand is very promising. The current use of a relatively large amount of low-smoke halogen-free thermoplastic sheath material, a small amount of cross-linkable sheath material. In addition, there are some highly demanding projects where cable insulation requires the use of cross-linkable low-smoke, halogen-free materials.
At the end of 1980s, China has begun to develop low-smoke, low-halogen, low-acid, halogen-free flame-retardant cable material formulations and products. Some manufacturers have produced low-smoke, halogen-free flame-retardant cable materials, but most of them have mechanical properties and Poor processing performance and other issues. Currently used halogen-free flame-retardant cable materials are still dependent on imports to a certain extent [8]. Its domestic requirements are still the subject of domestic cable manufacturers. Halogen-free flame-retardant wire and cable is the key development direction of flame-retardant wire and cable in the future. It is estimated that the annual consumption will be about 2 kt in the near future, and it is expected that the demand in the domestic market will reach more than l5 kt in 2010.
2.1.4 Semi-conductive shielding materials Semi-conductive shielding materials are necessary supporting materials for medium and high voltage power cables. The semi-conductive shielding material used for high-voltage and ultra-high voltage cross-over cables in foreign countries has high requirements for indicators, and domestic technology is not used. Currently, it is dependent on imports. For the l0kV power cable shielding materials, the properties and processes of domestic materials are also not very satisfactory. The ratio of the amount of shielding material and insulating material inside and outside is approximately 4:1. It is estimated that the annual amount of shielding material used in our country is 20-30 kt.
2.2 PVC cable materials In China, PVC cable materials were developed earlier, with more varieties and models. Recently, due to the improvement of environmental protection requirements at home and abroad, the development of PVC cable materials in China has gradually declined. However, due to the low price of PVC cable materials, combined with various advantages such as excellent mechanical properties, China's PVC cable material has a certain future development prospects. The recent domestic development of new products mainly include: PVC oil-resistant material, matt material. Irradiation crosslinking PVC cable materials.
Although at present, PVC wire and cable will not be eliminated immediately in foreign countries, but this can not but arouse the domestic wire and cable industry attaches great importance, the domestic should focus on the study of non-lead PVC or the development of new halogen-free environmentally friendly wire and cable. Although environmental protection wire and cable will take a long time to replace PVC cables in China, this is a general trend. Some domestic high-end projects have already put forward requirements for this.
2.3 PP cable material PP cable material insulation material is widely used in oil well submersible pump cable insulation layer. China's submersible pump and cable production plant needs about 5 kt PP cable material each year, and in addition to some domestically-produced materials, a large amount of imported materials are also needed. The main imported material is Pro-Fax SE191 from Himomo, USA.
China began to develop PP wire and cable insulation in the early 1980s.
Beijing Yanshan Petrochemical Co., Ltd. first successfully developed 1336D and 1396D, and subsequently developed 1296D and 2496D, and later Qilu Petrochemical, Shanghai Chemical Plant, Lanzhou Chemical Research Institute and other units also carried out this work.
3 Suggestions a) At present, the demand for crosslinkable insulation materials for high voltage power cables in China is huge. Has a good technical and economic benefits, basically all imported, mainly because there is no domestic base resin. Therefore, it is recommended that China Petroleum & Chemical Corporation introduce foreign advanced technology to develop and produce ultra-clean PE insulation materials for high-voltage cables in order to speed up its localization process.
b) China's high-voltage and ultra-high voltage cross-linked cables used semi-conductive shielding materials and halogen-free flame-retardant cable sheathing materials are basically dependent on imports, and some cable materials (such as high-performance telecommunications cable insulation materials) are still occupied by imported materials to a certain extent . Should increase the development of these special materials. To meet the large demand of domestic and foreign markets.
c) In view of the special circumstances of PVC cable materials, such as oil-resistant materials, matt materials, radiation cross-linked cable materials, etc., there are still certain development prospects, and they should also be studied.
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