Rubber sheathed cable
Rubber cable: wires and cables with rubber as insulation layer and sheath. Rubber sheathed cable is a soft and movable cable variety. The insulation layer and sheath are made of natural rubber, styrene-butadiene rubber, ethylene-propylene rubber, etc. In addition to meeting the insulation performance and physical and mechanical properties, they are required to be resistant to aging and wear. Some products require oil resistance and flame retardancy. According to the mechanical external force on the cable, the product structure is divided into three categories: light, medium and heavy. There is also appropriate connection in the cross section.
Scope of use of rubber cable
Rubber sheathed cables are widely used in various electrical equipment, such as household appliances, electric machinery, electrical devices and portable power cords of appliances. At the same time, they can be used in indoor or outdoor environmental conditions, and the products are used in all walks of life.
Rubber cable classification
Rubber sheathed cables are divided into heavy rubber sheathed soft cables (YC cables, YCW cables), medium rubber sheathed soft cables (YZ cables, YZW cables), light rubber sheathed soft cables (YQ cables, YQW cables), waterproof rubber sheathed soft cables (JHS cables, JHSP cables), welding machine cables (YH cables, YHF cables) YHD cables are tinned power cables for outdoor use. According to their uses, they are divided into power cables, control and signal cables, marine cables, aviation cables, mining cables, installation wires, etc.
Application range of rubber cables
Waterproof rubber sheathed cables and cables for submersible pumps:
Mainly used for submersible motors, models are JHS and JHSB.
Cables for radio devices: Mainly produce two types of rubber sheathed cables (one shielded and one unshielded), which can basically meet the requirements, models are WYHD and WYHDP.
Cable products for photography: In line with the development of new light sources, they have small structures and good performance, while meeting the needs of indoor and outdoor work, and gradually replacing some heavy and poor heat-resistant old products.
Generally, light rubber-sheathed cables are used in daily electrical appliances and small electric equipment, and require softness, lightness, and good bending performance;
Medium-sized rubber-sheathed cables are widely used in agricultural electrification in addition to industrial use;
Heavy-duty cables are used in places such as port machinery, searchlights, and large-scale hydraulic drainage and irrigation stations for household businesses.
This type of product has good versatility, a complete series of specifications, good performance and stability.
Differences between seven common rubber cable materials
- Natural rubber cable
Natural rubber is a highly elastic substance collected from plants such as rubber trees. Due to different manufacturing methods, natural rubber is divided into smoked sheet rubber and crepe sheet rubber. Smoked sheet rubber is used in the wire and cable industry.
(I) Composition and structure of natural rubber cable
The main component of natural rubber is rubber hydrocarbon. The basic chemical component of rubber hydrocarbon is isoprene, with a molecular formula of C5H8.
(II) Characteristics of natural rubber cable
- High mechanical strength. Natural rubber is a crystalline rubber with good self-reinforcement performance. The tensile strength of pure rubber can reach more than 170 kg/cm2.
- Excellent electrical insulation performance. Natural rubber has good electrical insulation performance, high insulation resistance and small dielectric loss tangent. `
- Good elasticity. Among all rubbers, natural rubber has the best elasticity.
- Good cold resistance. Natural rubber products can be used at -50℃.
- Good process performance. Natural rubber is easy to mix with vulcanizing agents and other compounding agents, and is easy to use with any rubber and plastic. The process is easy to control and the vulcanization performance is good.
The disadvantages of natural rubber are low heat resistance, thermal oxygen aging resistance, ozone resistance, oil resistance, and solvent resistance, and it will ignite and the source is limited.
- Styrene-butadiene rubber cable
(I) Type
Styrene-butadiene rubber is polymerized from two monomers, vinyl butadiene and styrene. The commonly used one in China is domestic rosin soft styrene-butadiene-30A, which is equivalent to international models 1500 and 1503.
(II) Characteristics
- Good electrical insulation performance, but not as good as natural rubber.
- The heat and oxygen aging resistance is better than that of natural rubber, but the ozone resistance is worse than that of natural rubber.
- It has a certain elasticity, but not as good as natural rubber.
- The wear resistance is worse than that of natural rubber, but the tear resistance, flexural resistance and cold resistance are not as good as those of natural rubber.
- The processing performance is poor, the adhesion is small, the shrinkage is large, and the rolling and extrusion are difficult.
In wires and cables, styrene-butadiene rubber and natural rubber are used in a certain ratio. - EPDM cable
(I) Types of EPDM cable
EPDM is a copolymer of ethylene and propylene. EPDM is divided into two types: EPDM and EPDM. The raw material for mining rubber sheathed cable-EPDM performance, mining rubber sheathed cable, mining high-voltage rubber sheathed cable insulation material-EPDM is a new type of rubber with the most promising development prospects. It has excellent comprehensive performance, and compared with other rubbers, it has particularly good weather resistance, ozone resistance, heat resistance, etc.
(II) Characteristics of EPDM Cable - EPDM is a non-polar material, so it has excellent electrical properties. Although it has some influence on its electrical properties after being damp, it is still much more stable than butyl rubber, natural rubber, and styrene-butadiene rubber. In particular, its corona resistance and free discharge resistance are outstanding. It is better than chlorosulfonated polyethylene, polyethylene, cross-linked polyethylene, and butyl rubber. For example, the corona resistance of butyl rubber does not exceed 2 hours, while that of EPDM can reach 2 months. The long-term AC breakdown voltage of EPDM insulated cable is 30-50% higher than that of butyl rubber insulated cable, the short-term AC breakdown cable is 10-20% higher, and the impulse breakdown voltage is 10% higher. Excellent electrical insulation performance. The electrical insulation performance after immersion in water is very stable because EPDM has low water absorption. The corona resistance and free discharge resistance are particularly outstanding, better than chlorosulfonated polyethylene, and better than butyl rubber, cross-linked polyethylene and polyethylene.
- Good heat resistance. EPDM rubber has better heat aging resistance than general rubber. It can be used for a long time at 85-90℃, and the short-term use temperature can reach 150℃.
- Excellent ozone resistance. EPDM rubber does not crack after 2430 hours in a medium containing 100PPm of ozone, which is better than butyl rubber and even better than chloroprene rubber.
- Good weather resistance. EPDM rubber does not crack after being exposed to the sun for three years, while natural rubber cracks after being exposed for 150 days.
- Good cold resistance. EPDM rubber has good impact elasticity, second only to butadiene rubber and natural rubber, and can maintain good elasticity at low temperatures; the brittle temperature is very low, and it still has good softness at a low temperature of -55℃, and can still be used at -65℃.
- Good chemical corrosion resistance. The biggest disadvantage of EPDM rubber is slow vulcanization speed, poor viscosity, and poor process performance. However, due to its excellent performance and abundant monomer sources, the price is not very high. Therefore, its application in the cable industry is expanding day by day, and it is mostly used to manufacture insulation materials for ship cables and mining cables.
IV. Chloroprene rubber cable
(I) Chloroprene rubber cable type
Chloroprene rubber is a chloroprene polymer. Due to different methods, chloroprene rubber is divided into three types: general type (GN type), 54-1 type (W type) and special type. The wire and cable industry uses general type and 54-1 type.
(II) Characteristics of chloroprene rubber cable
- Good mechanical properties. The physical and mechanical properties of chloroprene rubber are similar to those of natural rubber, and the elongation of raw rubber or carbon black reinforced vulcanized rubber is extremely high.
- Excellent aging resistance. Chloroprene rubber is resistant to aging, especially excellent in atmospheric and ozone aging resistance.
- It has special non-flammability and excellent oil resistance.
- Poor electrical insulation performance.
Chloroprene rubber is easy to self-sulfurize during storage, which is easy to cause early vulcanization (i.e. scorch) and roller sticking in industry.
Due to its poor insulation performance, chloroprene rubber is generally not used for insulation and is only used for low-voltage rubber insulated wires. However, due to its excellent ozone resistance, atmospheric aging resistance, excellent flame retardancy and extremely high mechanical properties, it is widely used in the sheath of marine cables and mining cables.
V. Nitrile rubber cable
(I) Types of nitrile rubber cables
Nitrile rubber is polymerized from butadiene and acrylonitrile. Nitrile rubber is divided into general-purpose nitrile rubber and special nitrile rubber according to its use. It is divided into hot nitrile rubber and cold nitrile rubber according to the polymerization method. According to the different propylene content, nitrile rubber is divided into different varieties. Domestically produced ones include nitrile-18 (propylene content is 18%), nitrile-26 (propylene content is 26%), and nitrile-40 (propylene content is 40%), which are soft and hard. The wire and cable industry commonly uses nitrile-18 and nitrile-26 general-purpose cold nitrile rubber.
(II) Characteristics of Nitrile Rubber Cable
- Excellent oil resistance and solvent resistance. The higher the acrylonitrile content, the better the oil resistance.
- General physical and mechanical properties. The mechanical properties of nitrile rubber without reinforcing agent are poor.
- Good heat resistance. The heat resistance of nitrile rubber is better than that of natural rubber and styrene-butadiene rubber.
- Good water resistance and low air permeability.
- Can be mixed with other rubbers or plastics to improve the performance of rubber.
The disadvantages of nitrile rubber are poor electrical insulation and cold resistance. The higher the acrylonitrile content, the worse the cold resistance. The brittle temperature is only about -20℃; the ozone resistance is not good; the process performance is poor. Nitrile rubber is not suitable for insulation. It can be used alone or mixed with polyvinyl chloride plastic to make oil-resistant cable sheaths, such as motor lead wires, oil and mining cables, and ship cable sheaths.
VI. Chlorosulfonated polyethylene rubber cable
(I) Types of chlorosulfonated polyethylene rubber cable
Chlorosulfonated polyethylene is a derivative of polyethylene. According to the chlorine content and the molecular weight of polyethylene, chlorosulfonated polyethylene rubber includes chlorosulfonated polyethylene 20, chlorosulfonated polyethylene 30, chlorosulfonated polyethylene 40, and chlorosulfonated polyethylene 45. The wire and cable industry generally uses chlorosulfonated polyethylene 20 and chlorosulfonated polyethylene 40.
(II) Characteristics of chlorosulfonated polyethylene rubber cable
- It has good physical and mechanical properties.
- It has good heat resistance and can be used continuously at a temperature of 120°C.
- It has excellent ozone resistance, sunlight resistance and atmospheric aging resistance, and will not crack after six years of outdoor exposure.
- It has good flame retardancy, second only to fluororubber and chloroprene rubber.
- It has excellent chemical resistance.
- It has good oil resistance.
- It has good corona resistance and radiation resistance.
- It has good process performance and can be used with other rubbers.
The disadvantages of chlorosulfonated polyethylene rubber are slightly large compression deformation and poor low temperature performance. However, due to its many advantages, it is a very promising rubber among synthetic rubbers. Chlorosulfonated polyethylene 40 is often used for insulation and sheath, and chlorosulfonated polyethylene 20 can be used for low-voltage wire insulation.
VII. Silicone rubber cable
First of all, silicone rubber is a special rubber, which is special in that it has good heat resistance. It is heat-resistant because its molecular chain is composed of (-Si-O-) bonds, and the bond energy of silicon-oxygen bonds is much larger than that of carbon-carbon bonds (456>348kJ/mol). In addition, Si is a non-combustible element and has the characteristics of inorganic materials, so it has high heat resistance. Silicone rubber is soft, resistant to ozone, corona, flame, has good insulation performance, is resistant to high and low temperatures (-60-200℃), and has very good corona resistance and arc resistance. It is a safe and reliable material for the production of wires and cables.
Secondly, cold resistance, plus heat resistance, means that silicone rubber cable has a wide working temperature range, and the same reason is that the bond energy is large.
In addition, it has excellent ozone aging, heat aging, UV aging and atmospheric aging performance.
It also has good oil resistance, solvent resistance, radiation resistance and flame resistance, good mildew resistance; in addition, it is odorless and non-toxic, and has no adverse effects on human health when used.
But it also has disadvantages: the tensile strength, tear strength and wear resistance at room temperature are much lower than those of natural rubber and other synthetic rubbers, the acid and alkali resistance is poor, and the price is expensive, and the processing performance is poor.
Vinyl silicone rubber is relatively good in silicone rubber in terms of processing technology, physical and mechanical properties, high temperature resistance and compression permanent deformation, and is widely used in the cable industry.
