Snack food bag bulk wholesale.Learn about composite materials for food packaging bags

Generally speaking, the basic structure of composite materials is that the outer layer of composite packaging materials should be materials with high melting point, good heat resistance, less scratches and burrs, good printing function, and good optical function. Commonly used materials include paper, aluminum foil, fiberglass, polycarbonate, nylon, polyester, polypropylene, etc.

The inner layer materials should have functions such as heat sealing, good adhesion, odorless, non-toxic, oil resistant, water resistant, and chemical resistant, such as heat-resistant plastic materials such as polypropylene, polyethylene, and polyvinylidene chloride. The middle layer of composite materials with three or more layers generally uses materials with good functions such as blocking gas and moisture, and shielding light, and high mechanical strength, such as aluminum foil, polyvinylidene chloride, cellophane, paper, polyethylene, etc.

Adhesive is applied between layers for bonding. Generally, solvent based thermosetting polyurethane adhesive is used between the outer layer and the middle layer, and modified polypropylene lotion adhesive or specially modified carbonyl propylene containing resin is used between the inner layer and the middle layer. The outer layer adhesive requires high bonding strength, simple process, and low cost; The adhesive used for the inner layer requires high temperature resistance, high peel strength, non-toxic, tasteless, and does not affect the nutritional composition of the food, which can effectively maintain the color, aroma, and taste of the food.

In recent years, foreign countries have developed a uniform coating agent on the surface of the substrate film to improve the airtightness, oil resistance, and chemical stability of packaging materials, making it suitable for various food packaging. Commonly used coating agents include polyvinylidene chloride resin and polypropylene polyvinylidene chloride resin. The methods of coating include single-sided coating and double-sided coating.

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