Application Problems of Green Packaging Materials and Corresponding Measures (1)

[Abstract] The present situation of the use and recycling of packaging materials is introduced. The use of packaging materials and the recycling of packaging wastes are described according to the connotation of green packaging.

[Key words] green packaging; packaging materials; packaging waste recycling

"Green packaging" has two meanings: - The entire packaging process will not cause pollution and damage to the ecological environment and human health; - The packaging materials used must be renewable and sustainable development materials.

The concept of green packaging began with the proliferation of white pollution in the past century. To control white pollution is to promote the rational use of packaging materials and the effective recycling of packaging waste.

First, green packaging materials and classification

Green packaging materials are packaging materials that we produce, manufacture, use, and recycle, are harmless to human health, have good protection for the ecological environment, and are recyclable. For example, polypropylene, corrugated paper, edible glutinous rice paper, corn paper, edible recycled plastic wrap, and our daily paper packaging products and paper handbags, paper cups, paper lunch boxes.

The new type of green packaging materials (degradable materials) that are currently being researched and developed globally are all directed against the “white pollution” that is difficult to handle. Therefore, according to the requirements of environmental protection and the ownership of materials after use, green packaging materials can be roughly divided into three categories.

The first is recyclable materials. Including paper, cardboard materials, molded pulp materials, metal materials, glass materials, general linear polymer materials (plastics, fibers), also includes degradable polymer materials;

The second is natural weathering materials that return to nature. Includes: - Paper product materials (paper, paperboard, molded pulp materials); - Degradable materials (photodegradation, biodegradation, oxygen degradation, photo/oxygen degradation, water degradation) and biosynthetic materials, grasses , wheat straw filling, shell filling, natural fiber filling materials, etc.; - edible materials;

The third is quasi-green packaging materials, which can be recycled and incinerated, without polluting the atmosphere and possibly regenerating materials. Including some of the non-recyclable recycling of linear polymer, network polymer materials, some composite materials (plastic / metal, plastic / plastic, plastic / paper) and so on.

Second, the development of green packaging materials

1. Green packaging printing paper

Among the four types of packaging materials, paper, plastic, metal, and glass, paper products have seen the fastest growth. The International Health Organization and domestic environmental protection experts believe that plastic waste may cause white pollution and is not conducive to environmental protection. Therefore, the use of plastic food bags should be gradually banned, and it is stipulated that green paper bags must be used. In the future, we must use non-toxic and harmless "paper bags."

Paper packaging materials are not only rich in resources, easy to recycle, but also easy to degrade. After the paper products are corrupted, they can either recycle recycled paper or use as vegetable fertilizers, reduce air pollution, and purify the environment. Therefore, compared with the other three plastic, metal, and glass packagings, using the "ecological cycle assessment method" technology for quantitative evaluation, paper packaging will become one of the most promising green packaging materials. Cartons, paper bags, paper drums, pulp molded products have become an important part of the modern packaging industry. At present, the output of paper and paperboard is increasing year by year. Packaging paper and paperboard account for more than 50% of the total output of paper and paperboard in China. Per capita consumption of paper has become an important indicator of the economic development level and civilization of a country. In the proportion of materials used for packaging products in various countries of the world, the use of paper accounted for the first place.

Many papermaking companies in Japan have researched and produced green packaging and printing paper for the printing and packaging industry, and have been active in the green packaging product market. Japan's Nippon Paper Co., Ltd. has developed and produced fully deep-stamped papers that use natural fibers as raw materials under the name “Npimold Paper”, and its stretchability is 5 to 10 times that of plain paper. The stamping paper can press texturing, patterns and three-dimensional curved surfaces when molding, similar to the processing of plastic products, and smoothing the convex image can achieve better sealing. The product can be produced by using the current plastic product equipment and molding according to the design scheme. Because it does not require heating and softening before processing, it can increase production efficiency and save energy. Challenge Five Co., Ltd. introduced biodegradable films and envelopes produced by Mit Subishi. Such films and envelopes are also produced from polylactic acid extracted from corn starch and can be offset using soybean ink. Dynic Co., Ltd. develops biodegradable flexible sheet "AuPairCornSheet" using cornstarch and fatty polyester as raw materials. The goal is to eventually replace PVC. This material is easy to machine and cut, easy to print, and its thickness can be adjusted according to the requirements. Landfill disposal does not pollute the environment. Because of the low calorific value during incineration, no toxic substances such as dioxins are produced, so it is less harmful to the environment.

The latest application market for new paper packaging is alcohol packaging. For example, Japan is now popularizing the use of carton packaging instead of glass bottles as alcohol packaging. Western countries also use paper materials to package wine and fill it into Tetra Pak's aseptic brick cartons. Because this Tetra Pak has the advantages of safety, durability, non-breakable, and not easy to explode, it is easy to carry and easy to open. In addition, one of its outstanding features is that it is composed of 6 layers of composite materials, which enhances the tightness and enhances the anti-alcohol leakage and volatilization of the package. At the same time, it can also block direct sunlight and prevent deterioration. Japan has also recently developed a composite carton for oils, consisting of paper as a substrate and 6-layer composite of aluminum and plastic. Its structure is: PE/paper/PE/AL/PET/PE. The package is not only lightweight, safe, but also suitable for printing.

A Japanese company has developed a packaging paper that has a dehydration function without heating or additives - PS wrapping paper. It absorbs water on the surface of food by absorbing water along the intercellular space, and it can absorb the deep water inside, and also has the function of absorbing water at low temperature. In this way, the wrapper can inhibit the activity of the enzyme, prevent the decomposition of the protein, reduce the proliferation of microorganisms, achieve the effect of maintaining the freshness of the food, concentrating the umami component, removing the water vapor, and improving the toughness. By using the packaged fish or meat as a dish, the heat energy for heating can be reduced, the deterioration of the heating oil can be prevented, the conditioning process can be facilitated, and no umami taste can be lost by freezing. The mechanism of the wrapper is to select a semipermeable membrane that can only permeate water as a surface material and a high permeability material and a polymeric water absorbent on the inside. Since the moisture in the food is osmotic pressure difference in the liquid state, the semipermeable membrane can be moved to the high osmotic pressure substance, so that the moisture is fixed by the polymer water absorbing agent.

Paper materials have always been considered as environmentally friendly materials and therefore can be recycled. However, some paper packages add other substances to increase the strength, which affects the remanufacturability. In Europe and America, a PLMEX food-specific wrapping paper is now popular. It does not contain fluorescent chemicals and chemicals that harm the human body. Made from paper, PLMEX is waterproof, oil-repellent, anti-stick, and heat-resistant, and can be washed and reused after use. It can be used up to 50 times. BASF Chemicals Group has also developed a protective coating applied to the surface of packaging paper. The packaging paper coated with polymer dispersion is resistant to water, moisture, oil and grease, and can be manufactured without changing existing production processes. Does not affect the effect of recycling.