Two composite methods of vacuum packaging bags

The dry composite method uses a variety of sheets or membrane materials as a substrate. Use a concave roller to apply a layer of adhesive on the surface of the substrate. Essence This is currently the most commonly used composite film production method in China. The characteristic of dry composite is that it adapts to a wide range of adhesives. Any piece of sheet or membrane can be compounded, such as PE film, PP film, PET film, PA film, etc. The composite composite strength of the dry composite method is high and the compound speed is fast, but the cost of dry compound is high. In addition, due to the amount of adhesives is generally 2.5-5 (G · m-2) (dry solid volume), there is a solvents residual and environmental environment. The pollution problem exists.

The legal process of coating is relatively simple, and it is difficult to process the obstacle resin of the film formation alone, such as PVA and PVDC, which can be composite. The melting temperature of PVC is 220 to 240 ° C, and the decomposition temperature is 200 ° C. It is necessary to add a film to the film to add plasticizers and stabilizers to increase the temperature of thermal decomposition and reduce the melting temperature. PVA is water -soluble. In actual use, the mixture of water and ethanol is used for solvents. Pleasters of 4 to 6 μm on PE or PP film on PE or PP film. Due to the poor water resistance of PVA, it can be added to the PVA solution. In order to improve its water resistance, it also improves the adhesion of PVA and PE and PP, which can save the bottom coating, for the convenience of making bags.

PE or PP membranes of PVA can be compounded with other membranes to form a composite film with PVA/PE (or PP)/LDPE structure. This membrane has a good blocking performance. The vacuum effect is more vacuum than PA/LDPE. Good, the cost is relatively low. The PVDC for coating is a climbing polymer for emulsion polymerization of chlorine polyethylene and acrylate monomers. After proper solvents and additives, coated with glass paper, BOPP, nylon, and polyester, so that it has a good obstacle The biggest problem with PVDC's use of wet gas resistance and thermal sealing performance is its safety and hygiene. It is generally believed that the monomer content should be less than 1 × 10-6.

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