Green Plastic Concept and Practice Analysis (3)

Green plastic practice and problems to be solved

The use of green plastic needs to address such issues as material consumption, recycling, reuse, disposal of waste plastics, and impacts on water quality and air.

Recycling

The foreign recycling of plastics has made great progress, and the recycling of discarded auto parts has also made great progress. Many countries have used recyclable and easy-to-recycle materials as the preconditions for the selection and design of automotive plastic parts.

China's annual output of plastic products (industrial enterprises above designated size) has reached 16.51 million tons. If you count small businesses, the conservative estimate is over 30 million tons, and this year it has maintained a strong momentum of growth. If 20% of plastic products are recyclable plastics, then China's recyclable plastic waste will be about 4 to 5 million tons per year. This does not include scraps and unused plastics that are produced in the company's production. Product recovery. The "Renewable Resources Recycling and Utilization Plan" proposes that by 2005 domestic recycling of spent I19 plastics should reach 5 million to 6 million tons. In reality, only about 2 million tons of waste plastics are recycled in China.

However, recycling needs to urgently solve the issues of classified recovery, recovery rate and production scale.

At present, due to the incompleteness of the recycling classification system, the classification of plastic products by raw materials is not obvious, and the concept of plastics classification and recycling has not yet been recognized by the public, resulting in the separation and recovery of different plastics. In order to promote the classification and recycling of plastics, the National Standardization Management Committee has approved the formulation of “Marking and Marking of Plastic Products” to facilitate the classification and recycling of plastic products.

Reuse

Plastic recycling industry has broad prospects in China. The plastics industry is the pillar of the national economy, and recycling is the only way for the sustainable development of the plastics industry. Plastic regeneration can not only save resources, ease the contradiction between the supply and demand of plastic materials, but also make an important contribution to environmental protection.

Recycling methods for plastic recycling include: melting regeneration, thermal cracking, energy recovery, recycling of chemical raw materials and other methods. Melt regeneration is a method of re-thermoplasticizing waste plastics. From the sources of waste plastics, this method can be further divided into two categories: First, the recycling of clean waste plastics recovered from scrap from processing plants and processing plants; Second, recycling of various plastic products mixed after use. . The former called pure regeneration, can produce better performance plastic products; the latter said composite regeneration, generally can only prepare relatively poor performance of plastic products, and the recycling process is more complicated. The thermal cracking method is a method of pyrolyzing selected waste plastics to obtain fuel oil and fuel gas. Energy recovery is a method of using the heat generated when the waste plastic is burned, such as fuel, power generation raw materials. Recycling chemical raw materials is a method of using chemical decomposition of waste plastics into chemical raw materials for recycling. In addition to the above-mentioned methods for recovering waste plastics, there are various methods for using waste plastics, such as smashing waste polystyrene foam into soil to improve the water retention, air permeability, and drainage of the soil, or as a filler and cement. Mixing building application materials such as lightweight concrete, or adding adhesives to press mats, etc., or artificial sand made of waste plastics will be applied to ground improvement materials and secondary concrete products, or recycling of waste plastics Used in the production of building materials, recycled plastic products, civil materials, paints, plastic fillers and so on.

The world's electrical and electronic market has paid attention to the recycling of waste plastics. International Business Machines Corporation (IBM) has started to code plastic parts for computers and business machines, and is developing reusable plastic electronic components and simplified disassembling equipment. The product structure, while also considering eliminating the surface coloring of components, controlling the amount of external adhesive for plastic additives to reduce the use of recycled technology components and additional parts.

Reduced design

The reduction of plastic packaging waste, reducing the generation of plastic packaging waste, should be the primary environmental strategy for plastic packaging. First of all, the design innovation of plastic packaging should be promoted so that plastic packaging can achieve light weight or thin-walled plastic packaging under the conditions that ensure its basic functions. Technological advances in the material synthesis process to date have enabled plastic varieties to achieve this goal.

degradation

While actively developing technologies for recycling plastics, research and development of biodegradable plastics has become a research hotspot in the plastic processing industry in various countries in the world. The researchers hope to develop a plastic that can degrade in a microbial environment to handle a large number of disposable plastics, especially mulching and reduce packaging pollution to farmland, forests, and oceans. The research goal is to develop a plastic that can ensure its various performances during use, and can be degraded by microorganisms in the environment once it is used up and completely enters the ecological cycle. At the same time, the production cost of this plastic is relatively low and it has corresponding economical efficiency. If it is such a biodegradable plastic, it can be composted with ordinary biological waste after use, without having to pay a great deal of money for collection, classification and regeneration. Moreover, the decomposition products enter the ecological cycle and no waste of resources occurs. In the research and development of biodegradable plastics, all countries in the world have invested a lot of financial resources and manpower, and have spent a lot of energy on research. The plastics processing industry generally believes that biodegradable plastics are the subject of new technology materials in the 21st century.

(to be continued)