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Plastic bag

A plastic bag, bag, or pouch is a container made of a thin, soft plastic film, nonwoven fabric, or plastic fabric. Plastic bags are used to hold and transport goods such as food, agricultural products, powders, ice, magazines, chemicals and waste. It is a common form of packaging.

Most bags are heat sealed at the seams, while some are glued or sewn together with adhesive.

Because plastic will never completely decompose, resulting in permanent pollution and environmental impact of plastic, many countries are making legislation to phase out light plastic bags. Each year, about 1 to 5 trillion plastic bags are used and discarded around the world.

Several design options and functions are provided. Some bags have linings that can hold more content, some can stand on shelves or refrigerators, and some can be easily opened or reclosed. The handle is cut or added to some.

Bags can be made of various plastic films. Polyethylene (LDPE, LLDPE, etc.) is the most common. Other forms, including laminates and coextrusion, can be used when physical properties are required.

Plastic bags usually use less material than boxes, cartons, or jars, so they are often considered "reduced or minimized packaging.".

According to the different structure, plastic bags can be suitable for plastic recycling. It can be incinerated in appropriate facilities for waste to energy conversion. They are stable and benign in sanitary landfill. However, if not handled properly, plastic bags can produce unsightly waste and damage certain types of wildlife.

The bag also has a handle, suspension hole, tape attachment or safety device. Some bags have easy to control opening preparation. Empty kitchen bags and certain foods usually have resealable functions, including compression seals. Some bags are sealed to prevent tampering, and some of them can only use the press reseal function after tearing the external seal with holes.

Water in bags is usually used for sealed frozen food, sometimes even for complete entrees. Bags are usually strong heat sealed nylon or polyester to withstand the temperature of boiling water. Some bags are porous or perforated to allow hot water to contact food: rice, noodles, etc.

In box bag packing is usually used to pack liquid such as wine and other liquid dimensions.

U.S. and European patent applications for plastic shopping bag production date back to the early 1950s, but these refer to composite structures in which the handle is fixed to the shopping bag during the second manufacturing process. The modern light shopping bag was invented by sten Gustaf thulin, a Swedish engineer. In the early 1960s, thulin developed a method for Celloplast, a packaging company in Norrk ö Ping, Sweden, to form a simple integrated bag by folding, welding and die cutting plastic flat tubes. Thulin's design and production of a simple, strong bag, with a high load-carrying capacity, and in 1965 obtained the global patent of Celloplast.

Since the mid-1980s, plastic bags have been widely used to transport groceries from stores to vehicles and houses throughout the developed world. With more and more plastic bags replacing paper bags, and other plastic materials and products replacing glass, metal, stone, wood and other materials, packaging materials war broke out, plastic shopping bags become the focus of widespread controversy.

In 1992, Sonoco products, Inc. in Hartsville, South Carolina, obtained the patent of "self opening polyethylene bag stack". The main innovation of the redesign is that taking a bag out of the rack opens the next bag in the stack.