FEP heat shrink tubing is also known as: Teflon heat shrink tubing. FEP heat shrink tubing is usually a relatively thin, shrinkable tube. 0.1mm thin and 2mm thick, the impression of thin-walled heat shrink tubing is usually seen: very light, very thin, poor compression resistance, thinness and lightness are the main characteristics of FEP heat shrink tubing. fEP, like other fusible fluoroplastics, is thermally moulded, die-cast and extruded (vacuum and pneumatic forming) using common methods. In standard equipment, all moulded parts in contact with fusible fluoroplastics should be made of corrosion resistant alloys.

FEP heat shrink tube filling process

1. The choice of inflation process. It is necessary to select a suitable process according to the product requirements. In general, it is required that the product is continuous, not too high in appearance and does not require roundness and that a continuous inflation process is selected. Conversely, a batch inflation process should be selected. 　　2. The influence of the crystallinity of the base tube on inflation must be fully considered: FEP is a crystalline fluoroplastic with a crystallinity of 70% or more. As the degree of crystallinity increases, the modulus of elasticity and hardness increase to varying degrees. Tensile strength, elongation and flexural resistance are correspondingly reduced. This is very detrimental to the production of heat shrinkable tubes, as high tensile strengths and elongation are required for expanding base tubes. Therefore, the base tube should be manufactured with as low a crystallinity as possible in order to make the base tube flexible and easy to expand. 　3. Appropriate extrusion process conditions are a key factor in improving expansion rates. When extruding, the difference between longitudinal and longitudinal properties of tubes with a large stretch ratio is greater and is not conducive to blow moulding. Therefore, in order to increase the expansion rate it is necessary to control smaller extrusion volumes and use smaller stretch ratios for the purpose of increasing the transverse strength of the tube, which can increase the expansion rate up to 50%.。 　　4. Pipe cracking is a common phenomenon in the production process of FEP heat shrinkable pipes. The main reasons are: firstly, the blow moulding temperature is too high, which leads to a reduction in the strength of the base tube and results in rupture. If the temperature of the blow mould is not evenly distributed, it will easily cause rupture. Over-expansion of the tube causes it to expand in the cooling section of the expansion mould and the tube stretches, which can easily cause rupture. During intermittent inflation, the pressure exceeds the transverse strength limit of the base tube, which can lead to rupture. Thirdly, in the intermittent inflation method, care should be taken when installing the nozzle to maintain parallelism between the base tube and the inflation mould so that the tube does not locally overheat and rupture under pressure.

FEP heat shrink tubing application areas:

1. FEP has the same range of applications as PTFE and is used in the electrical, radio, electronics, chemical industry, mechanical engineering, refrigeration, pharmaceutical and other industrial sectors. 　　　2. FEP is used as thin film printing plates, insulation for wires and cables, windings for generator wires, parts for electrical insulation (sheets, rods, tubes, frames and insulators), corrosion resistant structural products (oil-free lubricated mechanical parts), paints and glass cloth varnishes. The excellent corrosion resistance allows it to be used in chemical equipment, heat exchangers, fractionation towers, pumps, valves, tubes, seals, tube linings, transparent laboratory apparatus, etc. FEP extruded thin-walled tubes are used in heat exchangers and are suitable for heating. and cooling of highly corrosive liquids in the temperature range of -200 to 200°C. 　　　3. FEP parts used in the refrigeration industry stand up well to low temperature tests. fep sheets are used for the preparation of pneumatic and vacuum products. 　　4. FEP is used as wire and cable insulation for a variety of purposes and is particularly suitable for wires and miniature electronic components in electronic assembly circuits. 　　　5. FEP films are used as seals for capacitors, diaphragms and chemical equipment, and in the printing industry for the manufacture of printed boards and flexible cables. 　　6. The films can be welded, can be formed by vacuum processing, can be coated with metal without activation of the surface and can be bonded to metal and glass cloth under heat and pressure. 　　7. The FEP membrane is so resistant to gas permeation that it is used as a diaphragm to separate the sensitive element of the gas analyser from the analysis gas.

Features of FEP heat shrink tubing

1. the FEP material has a low surface free energy and coefficient of friction, resulting in good anti-adhesive and self-lubricating properties. the inner surface of the FEP tube can be separated from the composite part without any treatment. 　　2. Compared to polyolefin materials, FEP has higher tensile properties and toughness. During the heat shrink process and high temperature curing, heat shrink tubing reduces the possibility of rupture due to large shrink ring tensions and foreign objects. 　3. Heat shrinkable tubes manufactured by the expansion process can have a transverse shrinkage of 100% and a longitudinal shrinkage of between 1% and 3%, reducing the misalignment of the longitudinal heat shrinkage on the surface of the composite. 　4. FEP heat shrink tubing starts to shrink at 110°C and reaches values at temperatures of 160-180°C. When heat shrink tubing is used to protect the surface of the composite during the moulding process, the heat shrink material will shrink further and densify as the curing temperature gradually increases and, under a certain external pressure, the required composite will be available where the performance requirements and appearance requirements can be obtained. 5. Compared to polyolefin materials, FEP tubes have a lower transverse shrinkage rate. For straight or bent tubes with a tapered shape and a large variation in cross-sectional area at both ends, existing FEP heat shrink tubes are difficult to meet. Design and manufacture of heat shrink tubes with special shapes.