Brief introduction of heat shrinkable pipe development, application and production materials
1. What is a heat shrinkable casing?
Referring to heat shrinkable casing, according to the industry, the heat shrinkable casing can be divided into three categories: thin-walled heat shrinkable casing, medium wall heat shrinkable casing and thick wall heat shrinkable casing. The heat shrinkable casing is made of polyolefin material and shrinks in diameter after heating. Its diameter and thickness vary depending on the caliber. Due to different expansion processes, the expansion rate of heat shrinkable tubes, shrinkage will also be different, there are twice times, 3 times times, 4 times times or higher. Thermal shrinkage casing is often used in electrical engineering wire conductor connection and wire joints, insulation protection of the environment protective effect. It can also be used to bundle bound wires during wire repair to protect wires and small terminals, thus increasing the sealing of electrical junction boxes.
2, heat shrinkable casing application applications:
Place the heat shrinkable tube at the junction of the Wire and heat it with an oven, hot air gun, or similar tool. If you do not have these tools, you can also use a lighter or soldering iron (close but not touching), shrinkage is convenient, but the effect is general. A high-shrinkage heat shrinkable casing (conventional heat shrinkable casing is twice times shrinkage) can be used for connectors with no size. This provides good electrical insulation, isolation of dust, solvents and other foreign bodies. If heated too much, the heat shrinkable tube will melt and scorch just like any other plastic. A thermal shrinkage casing with a hot melt adhesive on the inner layer can provide a good sealing effect and better adhesion. The ordinary depends only on the friction between the material and the shrinkage and tightness of the heat shrinkable tube. Since the early 1970s, heat shrinkable tubes have been used extensively on the fiberglass spiral antennas of walkie-talkies. Millions of of antennas already use this versatile heat shrinkable casing. Thermal shrinkage casing is a thermoplastic material such as polyolefin, fluorinated polymers (such as FEP,PTFE or Kynar), PVC, neoprene, silicone rubber or fluorine rubber production.
Due to the use of different materials, there are two types of heat shrinkage: first, if the material contains many monomers, the pipe is heated to the softening point when the monomer will be polymerized, monomer polymerization will increase the density of the material, thus taking up less space, and achieve the effect of shrinkage. Second, the other is based on expansion, the production process is usually normal extrusion pipe, when heating above the polymer melting point of the mechanical external force to stretch the pipe or by the gas pressure expansion; Finally, cool quickly. Later, when used, the heat shrinkable casing is heated and the pipe shrinks back to its pre-expansion size. After extrusion, the material is crosslinked by using an electron beam with a peroxide. This crosslinking helps to keep the casing in its shape, whether before or after shrinkage, and if specifically required, the heat shrinkable casing can add UV stabilizers.
3. Heat shrinkable Casing Material
Different applications require different materials: PTFE (fluorine polymer) tubes have a wide operating temperature range (-55-175 ℃), low coefficient of friction, and high resistance to chemicals and puncture. Fluorine-containing polymers with high chemical resistance, fluorine rubber, and the other is widely used in hydraulic equipment. It has a high degree of flexibility and has a very high operating temperature of 55-220 ℃, making it suitable for thermal sensitive device protection.
High temperature applications of polyvinylidene fluoride (PVDF) tubes. Ethylene fluoride Propylene (FEP) is a lower cost alternative to PTFE, and elastic tubes maintain a high degree of flexibility even at low temperatures and meet strict international specifications. Their operating temperature range is-75 to. The material is resistant to many chemical substances (including diesel and gasoline) and has good abrasion resistance even in harsh environmental conditions. The common shrinkage ratio is 2:1.
Silicone rubber provides excellent scratch-resistant, high elasticity. The most common type of polyolefin heat shrinkable casing, with a maximum continuous use temperature from 55 to 125°c, and is used in military, aviation and rail industries. They are flexible and fast shrinkage, and the color of the product (including transparent) ranges widely, suitable for wires of various colors. In addition to black, they tend to have lower UV resistance, only black advice for outdoor use. The common shrinkage ratio is 2:1, while the high grade polyolefin heat shrinkage can be 3:1.
PVC tubes are available in a variety of colors and can be used outdoors. Thermal shrinkage sleeves for other special materials are present for high resistance under diesel and aviation fuels, or for weaving fibers to increase wear resistance in harsh environments.
不同的应用需要不同的材料:PTFE（氟聚合物）管有较宽的工作温度范围（-55到175℃），低摩擦系数，和高耐化学品和穿刺 。具有高耐化学性的含氟聚合物，氟橡胶，另一个被广泛应用于液压设备 。它具有高度的灵活性，具有非常高的工作温度在-55至220℃，使得它适合对热敏感器件保护。