Some packaging materials are gradually adopting non-toxic polyolefin resins, with additional materials such as polylactic acid, starch, chitosan or other cellulose fibers, photosensitizers, and biodegradable agents. Corresponding biodegradable bags are produced simply because they adhere to the concept of green chemistry. Among them, the biodegradable plastic used is a new material.

The bags made from plastic film are generally referred to as plastic bags. Commonly used plastic bags include: convenience bags, biodegradable canvas bags, tote bags, flat bags, seal bags, zipper bags, and other packaging bags. Biodegradable plastic bags can decompose automatically after about 90 days, under certain specific conditions.

Commonly used food plastic bags are mostly made of polyethylene film, which is non-toxic and can be used to package food. There is also a type of film made of PVC, which is also non-toxic. However, the additives added to the film for its intended purpose are often harmful to human health, which makes it toxic. Therefore, these films and plastic bags made from them should not be used to package food. To distinguish between PVC plastic bags and polyethylene plastic bags, the burning method can be used.

So how are the biodegradable components of eco-friendly bags obtained? Here are some reference methods:

(1) Natural polymer modification method. It is using natural polymers such as starch, cellulose, chitosan, lignin and seaweed as raw materials, and modifying these molecules through chemical reactions and copolymerization to synthesize plastic that is easily biodegradable.

(2) Chemical synthesis method. This method simulates the structure of natural polymers. Using simple functional groups as the starting point, active functional groups such as amide groups, peptide bonds, and ester groups are connected to the polymer chain, and compounds containing these functional groups are similar to the structure of natural proteins and fats, which makes them easily degradable.

(3) Microbial fermentation method. Many microorganisms can use certain organic compounds as a carbon source and secrete polyester and polysaccharide polymers through metabolism. These molecules are easily degraded and can be further reused.

When producing bags, bag-making machines and punching machines are necessary equipment. Generally, there are two types of bag-making machines that can achieve biodegradable production: biodegradable heat-sealing and cold-cut bag-making machines and heat-sealing and heat-cut bag-making machines. The bottom of the bags produced by heat-sealing and cold-cut bag-making machines is sealed first and then cut.

Generally, biodegradable plastic bags are made of polyethylene and starch, but this type of biodegradable plastic can only be degraded into smaller plastic pieces from large blocks, and the small molecule components of plastic are not completely eliminated, so its degradation is limited.

A new type of biodegradable material has been developed in China, which is made of polyvinyl alcohol, starch and photosensitizer. Polyvinyl alcohol is easier to degrade than polyethylene, and the photosensitizer can accelerate the degradation of plastic by absorbing sunlight, while starch can promote the biodegradation of plastic in soil. Therefore, this new type of biodegradable plastic is more easily degradable than previous ones, and after degradation, the plastic breaks down into simple structure molecules such as carbon and water, which makes it more environmentally friendly.

Manufacturers of garment bags and zipper bags remind you to pay attention to environmental protection, which is an urgent matter to eliminate white pollution. Everyone should make a contribution to this cause.