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In the production process of heat shrink tubing, expansion is the most difficult process to control. What method is used for its quality control?

The professional practice of domestic heat shrinkable tubing manufacturers, if an external force is applied to the material in this high elastic state, its melting temperature is about 115-135°C; the initial flow temperature of polyethylene increases with the increase of the irradiation dose High, for heat-shrinkable tubes, the radiation dose is generally 100-150kGy. Since the base material of the heat-shrinkable tube is a polyethylene multi-component blend system, it can ensure that the material is in a high elastic state, so as to obtain a higher expansion ratio and thermal shrinkage force. . When the temperature rises to the melting point, the uncrosslinked polymer transitions from the glass state to the viscous flow state, and the viscous flow occurs; while the crosslinked polymer does not undergo viscous flow and appears a high elastic state, which is formed by the crosslinking reaction inside the material. The effect of 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 It can return to the shape before stress. Therefore, the prerequisite for the implementation of the expansion process is that the material is in a high elastic state, that is, the material should be preheated to a temperature between its melting temperature and the viscous flow temperature before expansion.

The PVC heat-shrinkable sleeve has the special function of shrinking when exposed to heat, and can be cut for customers. It is used for the outer coating of various curtain rods, shower curtain rods, hanging rods, mop rods, broom handles, tool rods, telescopic rods, garden tools, poles and other tubular items. It can also be used for low-voltage indoor busbar copper bars, connectors, wiring harness identification, and insulation coating. High efficiency, less investment in equipment, and low overall cost. It is a new generation of packaging materials for lighting, LED pin wrapping, and guitar and packaging bottle wrapping. It can shrink when heated above 98°C, which is convenient to use. The products are divided into two series of 85°C and 105°C according to the temperature resistance, and the specifications are Φ2-Φ200. The products comply with the EU RoHS environmental protection directive. Used in electrolytic capacitors and inductors, the product has good high temperature resistance and no secondary shrinkage, and can be printed instead. It is used for single and combined packaging of various rechargeable batteries, and design and print patterns on behalf of them, whether it is for civilian, vehicle or military use, it is the best choice. PET heat-shrinkable tubing (polyester heat-shrinkable tubing) greatly surpasses PVC heat-shrinkable tubing in terms of heat resistance, electrical insulation, and mechanical properties. More importantly, the environmental performance of PET heat-shrinkable tubing is higher than the EU RoHs directive standard. It can meet the Sony SS-00259 environmental protection standard. PET heat-shrinkable tubing is non-toxic, easy to recycle, has no toxic effects on the human body and the environment, and is more in line with environmental protection requirements. Free of (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 Class 1 environmental management banned substances are used for electrolytic capacitors, inductors and other electronic components, high-end rechargeable batteries, toys and medical equipment, and can fully meet export requirements.