With the rapid development of industrial packaging, the existing manual packaging belt can not meet the needs of the current market, and machine pp packaging with its unique advantages, suitable for continuous rapid packaging of small and medium sized goods, is currently very popular at home and abroad.
The production route of the machine pp Packing Belt is roughly divided into the following parts: PP resin + filler} extrusion - cooling - hot drawing - ginning - heat treatment - winding. Each of these steps has its own unique process requirements and performance specifications as follows:
1. Extrusion molding The function of the extrusion molding part is to extrude raw materials with certain formulas with certain shapes and requirements.
The production of machine-use PP straps is generally mixed with PP in the masterbatch. The addition of PP masterbatch has the effect of plasticizing, increasing elasticity, and increasing moisture, making the PP polymer bonds easier to align and align in the stretching process, and can increase the tensile strength and other physical and mechanical properties of the Packaging Tape, but the APP adds To a certain extent, the rigidity of the product is affected. When the quantity exceeds a certain amount, the production process is significantly changed, the temperature of the die is lowered, and the discharge is accelerated. For example, the rigidity of the product produced under the premise of ensuring the product specification is reduced, which affects the product quality.
2、Cooling The shaped strip extruded from the die head enters the cooling water tank and is quenched and set. This process is the central process after extrusion molding. It can directly affect the quality of the subsequent process, ie, hot stretching. Therefore, the best cooling effect should be considered when designing the tank.
3. Hot Stretching The quenched baling strip is fed into the hot water tank for hot stretching by the first traction roller. The main purpose of this process is to increase the tensile strength of the packing strip and reduce the elongation at break.
4. Heat treatment After the hot-drawn secondary belt passes through the embossing roller, it enters the oven for heat treatment. The purpose of heat treatment is to eliminate the internal stress between the Packing Tape molecules, increase the intramolecular crystallization, and thus improve the product's stiffness.
5, air cooling and winding after heat treatment and packing temperature is higher, in order to ensure that the back of the winding can be carried out smoothly, and to make the crystal state in the tape saved, must have a cooling device.
