Do you know what role composite materials play in the printing of Small Cigar Paper Boxes?

Do you know what role composite materials play in the printing of Small Cigar Paper Boxes?

Single-layer plastic film often can not fully meet the requirements of protecting goods, beautifying goods and adapting to processing. So people developed two or more layers of the same or different kinds of packaging materials composite together. This kind of composite material overcomes the disadvantages of single material and obtains the excellent properties that single material does not have. At present, the composite material has taken the main position in the printing.

I. Basic structure of composite materials

Generally speaking, the outer material of composite packaging materials should be high melting point, good heat resistance, not easy to scratch, wear, printing performance, optical performance, often used paper, aluminum foil, cellophane, polycarbonate, nylon, polyester, polypropylene and so on.

The inner material should have heat sealing, good adhesion, tasteless, non-toxic, oil, water and chemical resistance, such as polypropylene, polyethylene, polyvinylidene chloride and other heat resistant plastic materials.

The middle layer of composite materials with more than three layers is usually made of materials with good performance and high mechanical strength, such as aluminum foil, PVDC, cellophane, paper, polyethylene and so on.

Between layers are coated with adhesive for bonding. In general, solvent-based thermosetting polyurethane adhesive is used between the upper layer and the middle layer, and modified polypropylene emulsion adhesive or specially modified carbonyl acrylic copolymerization resin is used between the inner layer and the middle layer. The outer adhesive requires high bonding strength, simple process and low cost; The inner adhesive requires high temperature resistance, high peeling strength, non-toxic, tasteless, does not affect the nutritional composition of food, can well maintain the color and flavor of food.

In recent years, a coating agent has been developed on the surface of substrate film to improve the air tightness, oil resistance and chemical stability of packaging materials, so that it is suitable for a variety of food packaging. Commonly used coating agents are polyvinylidene chloride resin and polypropylene - poly vinylidene chloride resin. Coating methods include single-side coating and double-side coating.

Two, currently commonly used food packaging composite materials

Double layer composite such as PT/PE, paper/aluminum foil, paper /PE, PET/PE, PVC/PE, NY/PVDC, PE/PVDC, PP/PVDC and so on.

Three-layer composite such as BOPP/PE/OPP, PET/PVDC/PE, PET/PT/PE, PT/AL/PE, wax/paper /PE, etc.

Four layer composite such as PT/PE/BOPP/PE, PVDC/PT/PVDC/PE, paper/aluminum foil/paper /PE, etc.

Five-layer composite such as PVDC/PT/PE/AL/PE, etc.

Six layers of composite such as PE/ paper /PE/AL/PE/PE, etc.

The cooking bag is a composite film food bag that can be sterilized at high temperatures. It was originally developed by the United States to meet the needs of astronauts. In the 1960s, the Japanese Toyo Tank Company obtained the patent license and realized mass production. Japan alone currently consumes 500 million bags a year. The United States, Germany and other countries are also growing at an annual rate of 10-20%.

Compared with glass and metal packaging containers, cooking bags can not only be sealed and sterilized, but also firmly sealed, easy to open, beautiful decoration, light weight, good impact resistance, convenient transportation and carrying.

According to sterilization temperature and storage time, cooking bag is divided into ordinary sterilization bag and ultra-high temperature sterilization bag.

Ordinary germicidal bag is generally heated at 121℃ below sterilization, most are made of two to three layers of composite materials. The shelf life of food is more than half a year. Ultra-high temperature germicidal bag is generally sterilized at 135℃, the bag material is more than three layers, sandwiched with aluminum foil, and the shelf life is 1-2 years. Some also use four - or five-layer composites.

The outer material of the cooking bag is mostly polyester film, the thickness is 10-16μm, which plays the role of strengthening and high temperature resistance; The intermediate material is 11-12μm aluminum foil, the main function is to isolate gas and water and to shield the light; The inner material is used as a cooking bag in direct contact with food and hot sealing, so the requirements for the inner material must meet the packaging health standards, but also require stable chemical properties, generally non-toxic polypropylene, thickness of 70-80μm, can also use HDPE and other polyolefin film.

At present, cooking bags are mainly used to pack canned food, and in Japan and Western Europe, they are also used to pack drinks, juices and the like.