Fluorine plastic cable, English name: FluoroplasticsCable, used to refer specifically to fluorine plastic for the jacket of the wire and cable. Fluoroplastic cable has excellent weather resistance, heat resistance, low friction coefficient, stable chemical properties, and good electrical insulation properties. Therefore, fluoroplastic cables have important uses in industries with harsh environments such as petroleum, metallurgy, chemical industry, electric power, and aerospace. In the production of wire and cable, the commonly used fluorine plastics are polytetrafluoroethylene, polyethylene glycol propylene, polyvinylidene fluoride, tetrafluoroethylene and ethylene copolymer, etc,Recycling fluoroplasticsIt is used to manufacture various heat-resistant and high-temperature-resistant insulated wires, measuring (oil) well cables, geological detection cables, heating cables, F-class and H-class motor lead wires, irradiation-resistant wires, electromagnetic wires, radio frequency coaxial cables, A- type cables of flame-retardant cables for coal mines, etc.

 

Kind

 

Fluorine plastic cable can be made into solid core and insulation in two forms, including physical foam fluorine plastic cable has been produced and used in foreign countries, in the domestic is still in the process of development, usually we say fluorine plastic cable usually refers to solid core fluorine plastic cable.

 

Three common forms: single-core cable, coaxial cable, multi-core cable.

 

1. Single-core cable

 

Or called high-temperature wire, its structure is that the inner conductor is single or multi-strand copper wire (tinned copper wire), the outer diameter of the conductor is 0.4~2.0MM, the insulation is fluoroplastic, and the thickness of the insulation layer is 0.3~0.5MM. It is often used as aviation wire, electronic and electrical equipment wiring and lighting line for special occasions.

 

2. Coaxial cable

 

The inner conductor is single or multiple strands of copper lead (tinned copper silver copper wire) with a diameter of 1.25~1.6MM. There are three insulation forms: A, fluoroplastic insulation with a thickness of 0.5~0.7MM,B, fluoroplastic foam insulation with a thickness of 2.5~3.0MM,C, fluoroplastic and polyethylene combined insulation, I .e. the inner layer is insulated with fluoroplastic and the outer layer is insulated with polyethylene, the thickness of fluorine plastic is 0.04~0.07MM. This type of cable is commonly used as a connection line for radio frequency cables and electronic equipment.

 

3. Multi-core cable

 

Single-core wires or coaxial cables are twisted together for multi-core cables. Among them, there are twisted pairs and non-twisted pairs, which are respectively used for industrial computer control and automatic instrument control. For special occasions, category 5 and super category 5 cables, data transmission, audio and video transmission, etc., this fluorine plastic cable is also used.

 

Characteristics

 

Fluoroplastics have a high degree of chemical stability and chemical corrosion resistance, fire resistance, high temperature resistance, flame retardant and other characteristics, so in the wire and cable industry has a wide range of applications, special cables such as: high temperature resistant cables, flame retardant cables, corrosion resistant cables, etc. Most of the use of fluorine plastic as the outer sheath. Fluorine plastic wire and cable has the following characteristics:

 

1, flame retardant: fluorine plastic oxygen index is high, the flame spread range is small, the amount of smoke produced is small. The cable produced by it is suitable for places with strict requirements on flame retardancy, such as computer networks, subways, vehicles, high-rise buildings and other public places. In the event of a fire, people can have a certain amount of time to be alienated without being smoked down by thick smoke. Get valuable rescue time.

 

2. Excellent electrical performance: Compared with polyethylene, fluoroplastic has a lower dielectric constant. Therefore, compared with coaxial cables of the same structure, fluoroplastic cables have smaller attenuation and are more suitable for high-frequency signal transmission. Nowadays, the use frequency of cables is getting higher and higher. At the same time, fluoroplastic can withstand high temperature, so it is often used as internal wiring of transmission communication equipment, jumpers between wireless transmission feeders and transmitters, and video audio lines. In addition, fluorine plastic cable dielectric strength, good insulation resistance, suitable for important instrument control cable.

 

Fluoroplastics have extraordinary thermal stability, making the fluorine plastic cable can adapt to the high temperature environment of 150~200 degrees, while the common polyethylene and polyvinyl chloride cables are only suitable for the working environment of 70~90 degrees. In addition, under the condition of the same cross-sectional conductor, the fluorine plastic cable can transmit a larger allowable current, which greatly improves the scope of use of the cable. Due to this unique performance, the fluorine plastic cable is often used in aircraft, ships, high temperature furnace and internal wiring and lead wiring of electronic equipment.

 

4. Perfect mechanical and chemical properties: Fluoroplastics have high chemical bond energy, high stability, almost unaffected by temperature changes, excellent weathering resistance and mechanical strength; and are not affected by various acids, alkalis and organic solvents. Therefore, it is suitable for large environmental climate changes and corrosive occasions, such as petrochemical, oil refining, oil well instrument control, etc.

 

5, conducive to welding connection: in electronic instruments, there are many wiring is connected by welding method, because the melting temperature of general plastic is low, easy to melt at high temperature, need skilled welding technology, and some solder joints must have a certain welding time, which has become the reason for the popularity of fluorine plastic cable, such as the internal wiring of communication equipment and electronic instruments.

 

6, the high price of fluorine plastic raw materials, cable production is difficult: high production costs, sales prices are naturally high, which also limits the application of products, however, because of this, making less competitive manufacturers, customers who need to use fluorine plastic cables will not be too much of the price factor.

 

Extrusion process

 

Due to the high price of fluoroplastic raw materials, the cable production extrusion process is difficult, and toxic gases will be discharged when the material is extruded during the production process, so the production cost of fluoroplastic cables is high, and their market sales prices are also high. The following are several points of attention in the extrusion process of fluorine plastic cable:

 

1. Selection of extrusion method

 

Fluoroplastic melt melt viscosity is extremely large, in the process of recycling fluoroplastics, it is not appropriate to use pressure extrusion, according to the melt has sufficient strength and allows stretching, it can be used sleeve die extrusion production of fluoroplastic wire and cable.

 

2. Extrusion die

 

Casing die extrusion, the mold is the most critical factor in the recovery of fluoroplastic extrusion process, inappropriate mold may cause loose sleeve, melt fracture, surface ripple, large fluctuations in outer diameter and other problems, serious may not be able to extrusion molding. In actual production, it is particularly important to control the reasonable tensile coefficient to ensure the adhesion between the insulation and the conductor. The stretching balance DRB value should not be less than 1.0, otherwise there will be insulation loose sleeve phenomenon, especially in single-line extrusion, its value should be adjusted to 1.05~1.15, but the DRB value should not be greater than 1.2, otherwise it will be in the extrusion speed When the melting vertebral body rupture, affecting product quality. In general, the length of the bearing line of the recycled fluoroplastic extrusion die is not more than 15mm. For the processing line diameter is larger, the draw ratio DDR between 5~10, the length of the line of the extrusion die should be increased to about 12mm, so as to increase the pressure of the molten resin in the die and reduce the fluctuation of the extrusion diameter, so as to achieve the purpose of stable extrusion.

 

3. Extrusion temperature Due to the high price of fluoroplastic raw materials, the cable production extrusion process is difficult, and toxic gases will be discharged when the material is extruded during the production process, so the production cost of fluoroplastic cables is high, and its market sales price is also higher. high. The following are several points of attention in the extrusion process of fluorine plastic cable:

 

1. Selection of extrusion method

 

Fluoroplastic melt melt viscosity is extremely large, in the process of recycling fluoroplastics, it is not appropriate to use pressure extrusion, according to the melt has sufficient strength and allows stretching, it can be used sleeve die extrusion production of fluoroplastic wire and cable.

 

2. Extrusion die

 

Casing die extrusion, the mold is the most critical factor in the recovery of fluoroplastic extrusion process, inappropriate mold may cause loose sleeve, melt fracture, surface ripple, large fluctuations in outer diameter and other problems, serious may not be able to extrusion molding. In actual production, it is particularly important to control the reasonable tensile coefficient to ensure the adhesion between the insulation and the conductor. The stretching balance DRB value should not be less than 1.0, otherwise there will be insulation loose sleeve phenomenon, especially in single-line extrusion, its value should be adjusted to 1.05~1.15, but the DRB value should not be greater than 1.2, otherwise it will be in the extrusion speed When the melting vertebral body rupture, affecting product quality. In general, the length of the bearing line of the recycled fluoroplastic extrusion die is not more than 15mm. For the processing line diameter is larger, the draw ratio DDR between 5~10, the length of the line of the extrusion die should be increased to about 12mm, so as to increase the pressure of the molten resin in the die and reduce the fluctuation of the extrusion diameter, so as to achieve the purpose of stable extrusion.

 

3. Extrusion temperature

 

When extruding and recycling fluoroplastics, the temperature setting is proportional to the extruded wire diameter and speed. The larger the wire diameter, the higher the extruder screw speed, the higher the set temperature. In the extrusion process, by observing the state of fluoroplastic melting cone to determine whether the temperature is appropriate. If the temperature is too low, it will lead to the existence of internal stress in the insulation and cracking; excessive heating will lead to local decomposition of fluoroplastics, resulting in the existence of bubbles on the surface of cable insulation or sheath, seriously affecting product quality. At the same time, the wire core should be preheated before entering the head, and a heat preservation and heating cover should be added outside the mold and the molten cone to avoid temperature changes leading to viscosity changes of the molten cone, which will affect the extrusion speed and product quality.

 

4. Cooling control

 

Fluoroplastic is a crystalline organic polymer material, so it is not appropriate to use the cooling quenching method, due to the high extrusion temperature of fluoroplastic, so the temperature of the cooling medium should reach the best proportion of material crystal nucleus growth rate and grain growth rate. The insulation or sheath after extrusion shall be cooled by sectional cooling, I .e. the water temperature of the water tank shall be set from high to low, so as to avoid loose sleeve or internal stress in the extrudate caused by rapid cooling.

 

When extruding and recycling fluoroplastics, the temperature setting is proportional to the extruded wire diameter and speed. The larger the wire diameter, the higher the extruder screw speed, the higher the set temperature. In the extrusion process, by observing the state of fluoroplastic melting cone to determine whether the temperature is appropriate. If the temperature is too low, it will lead to the existence of internal stress in the insulation and cracking; excessive heating will lead to local decomposition of fluoroplastics, resulting in the existence of bubbles on the surface of cable insulation or sheath, seriously affecting product quality. At the same time, the wire core should be preheated before entering the head, and a heat preservation and heating cover should be added outside the mold and the molten cone to avoid temperature changes leading to viscosity changes of the molten cone, which will affect the extrusion speed and product quality.

 

4. Cooling control

 

Fluoroplastic is a crystalline organic polymer material, so it is not appropriate to use the cooling quenching method, due to the high extrusion temperature of fluoroplastic, so the temperature of the cooling medium should reach the best proportion of material crystal nucleus growth rate and grain growth rate. The insulation or sheath after extrusion shall be cooled by sectional cooling, I .e. the water temperature of the water tank shall be set from high to low, so as to avoid loose sleeve or internal stress in the extrudate caused by rapid cooling.

This article comes from:www.tflpfa.com

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