In the production process of heat shrinkable tubing, expansion is the most difficult process to control. What method is used for quality control?
According to the professional practice of domestic heat-shrinkable tubing manufacturers, if an external force is applied to the material in this highly elastic state, the melting temperature is about 115～135℃; the initial flow temperature of polyethylene rises with the increase of the radiation dose High, for heat-shrinkable tubes, the radiation dose is generally 100～150kGy. Since the base material of heat-shrinkable tubes is polyethylene multi-element blending system, it can ensure that the material is in a high elastic state to obtain higher expansion ratio and heat shrinkage force. . When the temperature rises to the melting point, the uncrosslinked polymer transitions from a glass state to a viscous flow state and viscous flow occurs; while the crosslinked polymer does not undergo viscous flow but appears a highly elastic state, which is formed by the crosslinking reaction inside the material The effect of the three-dimensional network structure. At this time, the corresponding initial flow temperature is about 180°C, so the preheating temperature of the heat shrinkable tube should be controlled between the two, that is, about 140°C, the material can produce elastic deformation, that is, once the external force is removed, the material Can return to the shape before the force. Therefore, the precondition for the expansion process to be implemented is that the material is in a highly elastic state, that is, the material should be preheated to a temperature between its melting temperature and viscous flow temperature before expansion.
PVC heat shrinkable tubing has a special function of shrinking when exposed to heat, and can be cut on behalf of customers. It is used for the outer covering of all kinds of curtain rods, shower curtain rods, hanging rods, mop rods, broom handles, tool rods, telescopic rods, garden tools, support rods and other tubular articles. It can also be used for the identification and insulation coating of low-voltage indoor busbar copper bars, joints and wiring harnesses. High efficiency, low equipment investment and low overall cost. It is a new generation of packaging materials used for the wrapping of lighting, LED pins, and the wrapping of guitars and packaging bottles. It can shrink when heated above 98℃, which is convenient to use. The products are divided into two series of 85℃ and 105℃ according to the temperature resistance. The specifications are Φ2-Φ200. The products comply with the EU RoHS environmental protection directive. Used in electrolytic capacitors and inductors, the products have good high temperature resistance and no secondary shrinkage, and can be printed on behalf of them. It is used for single and combined packaging of various rechargeable batteries, and designs and prints patterns on behalf of them. Whether it is for civilian, automotive or military use, it is the best choice. PET heat-shrinkable tubing (polyester heat-shrinkable tubing) greatly exceeds PVC heat-shrinkable tubing in terms of heat resistance, electrical insulation performance, and mechanical properties. More importantly, the environmental performance of PET heat-shrinkable tubing is higher than the EU RoHs directive standard. It can reach Sony SS-00259 environmental protection standard. PET heat-shrinkable tubing is non-toxic, easy to recycle, will not have toxic effects on the human body and the environment, and is more environmentally friendly. Does not contain (Cd), lead (Pb), mercury (Hg), hexavalent chromium (CrVI), polybrominated biphenyls (PBBs), polybrominated biphenyls (PBBEs/PBDEs), polychlorinated biphenyls (PCB), polychlorinated terphenyls (PCT) , Polychlorinated naphthalene (PCN) and other prohibited substances for environmental management, which are the outer covering of electrolytic capacitors, inductors and other electronic components, high-end rechargeable batteries, toys and medical equipment, which can fully meet export requirements.