Characteristics And Production Process Of Dual Wall Heat Shrinkable Tubing

- Feb 22, 2019-

Brief Analysis of the Characteristics of Waterproof and Rubber-containing Heat Shrinkage Pipe and the Production Process of Heat Shrinkage Pipe

Waterproof heat-shrinkable pipe with rubber is also called heat-shrinkable casing with environmental protection belt. Its outer layer is made of high-quality and soft cross-linked polyolefin material and inner layer is made of hot melt adhesive. The outer material has the advantages of insulation, corrosion protection and wear resistance, while the inner material has the advantages of low melting point, waterproof, sealing and high adhesion. Waterproof and glue-containing double-walled pipes are widely used in waterproof and leak-proof wiring of electronic equipment, anti-corrosion protection of wire branches, repair of wires and cables, waterproof wiring of water pumps and submersible pumps, etc. Suitable for irregular shape of insulation and sealing. Characteristics: 1) Shrinkage ratio 3:1, 4:1; 2) Flame retardancy, sealing, waterproof, strain buffering, environmental protection (ROHS), extinguishing of outer layer; 3) Initial shrinkage temperature 70 C, complete shrinkage temperature 125 C; 4) Working temperature range: -45 C-125 C; (5) Melting temperature of inner layer: 70 C-100 C; 5) Adhesive layer can be bonded to plastic, rubber and metal. Our company can adapt to the characteristics of various industries, these harsh environment design, with specific products.

How to calculate the axial shrinkage rate of heat shrinkable pipe? The formula for calculating the axial (length direction) shrinkage rate of heat shrinkable casing: shrinkage rate = (pre-shrinkage length-post-shrinkage length) / pre-shrinkage length * 100%.

In the process of storage and transportation, thermal shrinkage products should avoid direct sunlight or ambient temperature exceeding 60 degrees. When ambient temperature exceeding 60 degrees, thermal shrinkage products can shrink partially.

The production process of double-wall heat-shrinkable pipe is divided into five steps, usually followed by master batch granulation, pipe extrusion, irradiation cross-linking, pipe expansion and printing packaging.

First of all, master batch granulation is to take the raw material of the prescribed formula, and then mix it in an internal mixer to produce the required master batch particles for the corresponding heat shrinkable tube.

Secondly, pipe extrusion is to put the above masterbatch into the mixer and extrude qualified pipes according to a certain process. The wall thickness and deviation of pipes in the extrusion process have a greater impact on the quality of heat shrinkable casing.

The third is irradiation cross-linking (referred to as irradiation). The irradiation cross-linking process is the most critical process in the manufacture of heat-shrinkable tubes. After extrusion, the tubes need to be irradiated by an electron accelerator to increase the degree of cross-linking of polymer materials in the high-temperature heat-shrinkable tubes, making them a network-like structure. There are chemical bonds linking between the segments and there is a strong interaction force. If the irradiation crosslinking degree is appropriate, qualified heat-shrinkable pipes can be manufactured. If the irradiation crosslinking degree is too high, the pipes can not expand, the crosslinking degree is too small, the pipes can not expand, or they can not expand to a larger multiple, which is easy to crack, and the shrinkage force of the heat-shrinkable pipes manufactured is not enough, and the shrinkage effect is not good.

Fourth, pipe expansion. After irradiation crosslinking, the heat shrinkable pipe passes through the expander, which makes the stretching resistance of the pipe chain very large. The internal stress of the retraction is not enough to satisfy the resistance. Therefore, in the natural state, the shape of the heat shrinkable pipe after expansion is maintained.

Finally, printing packaging.