成人免费无码不卡国产区二区三区_日韩精品主播一区二区_成人电影在线一区二区_午夜无码伦费影视在线观看_亚洲AⅤ少妇熟女猛男_无码的黄a在线观看_狠狠做五月综合五月天婷婷_91绿帽人妻社区论坛_精品国产福利电影_色欲AV免费播放口

In China, with the implementation of mandatory garbage classification in the past two years, biodegradable materials have gradually become a hot concept. What are biodegradable materials, and in which fields are they used? How do we distinguish this material?

       The development of plastic packaging bags in a green direction is closely related to people's concern for environmental protection. Since the 1970s in the last century, many countries have begun to develop green plastic bags. Since polyolefin materials mainly made of PE and PP cannot be decomposed in a short period of time, scientists finally synthesized a series of polyester materials that can be decomposed by microorganisms through research, as well as some renewable resources (such as straw, Bagasse, corn starch, etc.) are extracted from synthetic green materials to produce truly biodegradable green plastic bags.
       Biodegradable packaging bags must meet three conditions:
First, it must be completely degradable, and the products are carbon dioxide and water;
Secondly, under industrial composting conditions, it must be completely degraded within 180 days;
Third, after degradation, it does not produce any toxicity and has no impact on the environment.
       Biodegradable materials have been widely used in custom-made packaging bags, which can be processed in a composting factory and turned into organic fertilizers in 30-45 days. Since the 1990s, Western countries have begun to use biodegradable shopping bags and food waste bags.
        Due to the relatively short time of using biodegradable packaging bags in China, many customers who need customized packaging bags do not know how to identify biodegradable packaging bags. Since this kind of packaging bag is not significantly different from ordinary plastic bags in appearance, a series of international standards have been issued: ISO14855, EN13432, ASTM-D6400, and currently there are three main internationally recognized certification marks: OK Compost", "Seedling" and "BPI". Therefore, if there are these kinds of certification marks, they can be recognized as biodegradable packaging bags.