Development and Application of Degradable Plastics at Home and Abroad (Part Two)

Industrialization development:

Focusing on biodegradable plastics, we will focus on industrial development in the following areas:

(a) Develop the following materials:
1. Polycaprolactone (PCL) This plastic has good biodegradability and its melting point is 62 degrees Celsius. The microorganisms that decompose it are widely distributed under irritated or anaerobic conditions. As a biodegradable material, it is mixed with starch, a cellulose-based material, or polymerized with lactic acid. Due to its low melting point, it is stable under high temperature and high humidity conditions compared to other aliphatic polyesters.

2, polybutylene succinic acid (PBS) and its polymer to PBS (melting point of 114 degrees Celsius) as the basic material for the production of a variety of high-molecular-weight polyester technology has reached the level of industrial production. The products developed using it are foamed materials used as packaging materials for household appliances and electronic instruments. Japan Catalyst Corporation, Mitsubishi Gas Chemical Corporation, etc. introduced carbonate (ester) knots into PBS to develop water-resistant and degradable plastics.

3, polylactic acid (PLA) melting point of 175 degrees Celsius, was processed into a film or fiber, with better resistance to hydrolysis. In Germany, the lactic acid boxes produced in 1998 were commercialized. This substance also has the effect of promoting the growth of plants, so it is expected to use it as a container for plant transplantation or plant cultivation. Shimadzu Corporation established a device for producing polylactic acid in 1994 and opened up applications in various fields. By nip rolling, it can be made into transparent, good mechanical properties of fibers, films, containers, lenses, and the like.

4. Poly-3-hydroxybutyric acid (PHB) and its polymers Many countries are currently researching and developing the use of microbes to produce thermoplastic polymer materials. Among them, poly-3-hydroxybutyric acid has the highest production efficiency. However, its crystallinity is too strong, its mechanical properties are not good, and it is easily decomposed by heat, making it difficult to process. Mixing PHB with PCL improves its physical properties. The use of microorganisms to produce PHB and polyhydroxyvaleric acid polymer technology has emerged in the United Kingdom since the 1970s began to use this material to produce shampoo bottles.

5. The technology of producing degradable plastics has been successfully studied by using starch plastics to mix aliphatic polyesters and starches. Starch is very important as a direct or indirect raw material for the production of degradable plastics. In addition to corn and sweet potatoes, starches such as cassava, sago coconut, and taro can also be used. In Europe and the United States, a mixture of gelatinized starch and aliphatic polyester is widely used to produce products such as garbage bags. As long as there is water in the starch, it will be gelatinized after heating and has plasticity. However, its disadvantage is that it does not have water resistance. By controlling the structure of gelatinized starch and PCL, a mixture having excellent water resistance and mechanical properties can be obtained.

6. Aliphatic Polyester and Polyamide Copolymer (CPAE) This material was developed to improve the physical properties of aliphatic polyesters. It has improved melting point and tensile strength, and is a new generation of degradable plastics. . However, the degradability of its lipase decreases as the amount of nylon increases. Recently, Bayer AG successfully used nylon and polyester to successfully develop CPAE, polymerized it with polyethylene glycol, and developed a biodegradable and photodegradable plastic.

(b) Form the following products:

1. Degradable resin and masterbatch, including: biodegradable resin, photo/biological degradable masterbatch, and composite degradable masterbatch.

2, degradable plastic products, including: compost bags, garbage bags, shopping bags, electronic bags, plastic film, catering utensils, golf nails, foam materials.
3, ordinary plastic products, including: shopping bags, garbage bags, office plastic and so on.

Market and Benefit Analysis

Internationally, the production and application of photodegradable plastics has been more than 10 years old. Biodegradable plastics, especially starch-added biodegradable plastics, have developed extremely rapidly in recent years. According to the report of Freedoia, the sales volume of degradable plastic products in the United States was 230,000 tons in 1987, 8.3 million tons in 1989, and 3 million tons in 2000. The sales volume of degradable plastic products in Canada was 50,000 tons in 1989 and reached in 2000. 200,000 tons. According to a survey conducted by Structure Analysis & Surveys in the United States in the early 1990s, the development of degradable plastics will be faster in Europe and Japan. At that time, it is estimated that by 1995, the market share of the United States in the world's degradable plastics has dropped from 60% in 1990 to 41%. , while Europe will rise from 38% to 53% and Japan from 2% to 6%.

From the analysis of the types of degradable plastics, in North America, in 1989, total sales of degradable plastics were 880,000 tons, of which 160,000 tons were biodegradable plastics. At that time, it was predicted that by the year 2000, the total demand for degradable plastics would reach 3.2 million tons, including 1.1 million tons of biodegradable plastics, 1.05 million tons of photodegradable plastics, 900,000 tons of photo-biodegradable plastics, and 150,000 tons of other degradable plastics. From 1994 to 2000, the average annual growth rate was 7.1% for biodegradable plastics, 9.6% for photodegradable plastics, 11.2% for photo-biodegradable plastics, and 5.3% for other degradable plastics. According to this forecast, the growth of photo-biodegradable plastics will be the fastest.

From the field of degradable plastics applications, of the 880,000 tons of total degradable plastics sold in North America in 1989, the largest amount was used for packaging, reaching 760,000 tons, including 560,000 tons of packaging and other bags (of which 475,000 tons were garbage bags. 85,000 tons of shopping retail bags, etc.) 105,000 tons of beverage cans and 95,000 tons of other packaging. Other non-woven fabrics (sanitation) 55,000 tons, 25,000 tons for agriculture, 40,000 tons in other areas. At that time, it was forecasted that by the year 2000, 2.48 million tons of packaging will be used, 300,000 tons of non-woven fabrics, 160,000 tons of agricultural products, and 260,000 tons of other products. From 1989 to 1994, the average annual growth rate for packaging was 16.2%, 21.4% for non-woven fabrics, 22.9% for agriculture, and 20.1% for other areas. The average annual growth rate from 1994 to 2000 was 7.5% for packaging, 12.9% for non-woven fabrics, 14.8% for agriculture, and 17.3% for other areas. From the perspective of our country, the application fields of biodegradable plastics mainly include:

1. Agricultural plastic film: The agricultural film is a three-pillar product (fertilizer, pesticide, and plastic film) for agricultural production. It was originally a state-controlled product and has remained relatively tight on the market. Since 1979, the agricultural film covering cultivation technology has been promoted vigorously in China. In 1980, the area covered by agricultural film was only 25,000 mu, and by the year of 1992, it reached 50 million mu. The application of agricultural film was developed from the initial cotton and vegetables. To cultivate cash crops such as peanuts, fruits, beets, sugarcane, tobacco, fruits and food crops such as rice, early rice, wheat, and corn. The promotion and popularization of agricultural film has achieved significant economic benefits. According to statistics, the yield increase brought by the agricultural film from 1982 to 1987 was 7.1 billion yuan; from 1978 to 1989, the mulching film-mulching cultivation technology cumulatively increased 28 billion kilograms of grain and cash crops. From the above statistics, we can see the very significant economic benefits brought by the promotion and application of agricultural film.

At present, the output of agricultural film in China is 650,000 tons. Although China has become the largest country in terms of agricultural film coverage in the world, at present, the cultivation area of ​​agricultural film only accounts for about 25% of the existing cultivated land, and our country plans to cover the agricultural film in 2000. The giant of 150 million acres requires more than 1.5 million tons of agricultural film. The market capacity is very large.

2. Food packaging film, one-time living film, one-time medical film, industrial product packaging film, etc.: In 1993, the demand was 1.4 million tons, which was increasing by 15% every year. The large amount of consumption was supermarkets and department stores. Because the extensive use of these membranes, especially in large and medium-sized cities, has caused serious pollution to the environment, the promotion and application of degradative membranes will surely attract the attention of the government and society. The market is vast and far-reaching.

3, degradable foam net, as a new product, no domestic manufacturers, its market prospects are very considerable. Our country is rich in thousands of tons of various fruits, plus a variety of glass, wine, ceramics and other packaging, its market capacity is very large, so the market prospects for such products is extremely broad. It is estimated that the annual domestic demand will be about 50,000 tons.

4. Degradation of disposable foam plastic tableware such as fast food boxes, along with the economic development of our country, the improvement of people’s living standards has emerged. Due to its characteristics of hygiene, convenience, and low cost, it has been widely used in various tourist cities and railway systems. With the rapid development of production and variety, an industry with more than 100 production lines and a processing capacity of 100,000 tons has been formed so far. According to statistics, the demand for fast food boxes in China reached 2.5 billion in 1995, and the railway system alone reached 1 billion. There are 200 million instant noodles, an annual output value of 1.2 billion yuan, and a demand of 3.2 billion in 1997. Its market prospect is very broad. At present, at least ten cities in China have stipulated that they must use degraded fast food boxes.

In short, the most prominent advantage of degradable plastics is that it can be degraded and does not pollute the environment. It is an inevitable trend to replace polyethylene plastics. The upgrading of plastic film products is also imperative. It is predicted that the current market size will reach 30 billion yuan, and it will increase at a rate of 30-50% per year.

From the above analysis of market demand, economic benefits, and social benefits, it can be seen that the development of environmental protection biotechnologies, especially biodegradable plastics and other products, has a minimal market risk and policy risk. After 20 years of development, China’s biotechnology has been applied. The environmental protection field is just right. It can be foreseen that through the effective organization within the bio-economic park and the comprehensive utilization of technological, financial, and institutional advantages, it is entirely possible to realize industrialization in a relatively short period of time.