Know this, let you know more about recycled materials.

TED's video "What really happens to the plastic you throw away" tells the story of the different fate of the three Coke bottles. At the same time, it also points out that recycling is the road to sustainable development that we should explore and practice in the future. Among the various recycled materials made from the last Coke bottle, there are textile and apparel products used in our daily life.

How do recycled materials be used in textiles? First, it is necessary to produce a recycled fiber material. Since it is usually produced by chemical synthesis using a polymer material, such a material is also referred to as "recycling chemical fiber."

1. Recycling chemical fiber

Recycled Chemical Fibers are waste chemical fibers or textiles and other waste polymer materials that are re-used after physical opening, or melted after melting or dissolving, or recycled polymer materials. Further cracking into small molecules repolymerizes and re-spins the fibers. Regenerated Chemical Fiber is also known as a regenerated chemical fiber because it uses fiber as a raw material to prepare fibers and regenerates it.

The recyclable chemical fiber mainly includes polyester fiber, polyamide fiber, polypropylene fiber, polyurethane fiber, polyacrylonitrile fiber, polyvinyl chloride fiber, etc., which is basically similar to the original chemical fiber in terms of composition, structure and physicochemical properties. The relatively mature fibers are mainly polyester fibers and polyamide fibers. Other fibers are recycled and reused as materials similar to their monomers or polymers, and cannot be directly used as textile materials.

2. Recycling polyester fiber

According to the principle of regeneration, the preparation method of recycled polyester fiber can be mainly divided into physical method and chemical method. The physical method refers to direct spinning and spinning of waste polyester material as raw materials after sorting, washing and drying. The regeneration method refers to a process in which a waste polyester material is depolymerized into a polymerization monomer or a polymerization intermediate by a chemical reaction, and a process of regenerated polymerization and melt spinning is carried out after purification and separation.

The physical method is the leading polyester recycling method because of its simple production technology, simple process flow and low production cost. The production capacity of recycled polyester is more than 70%~80%, which is recovered by physical method (that is, video). The way the cola bottle is recycled.)

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However, in recent years, the chemical law has shown an increasing trend through the innovation of equipment and technology. Its main advantage is that it has low requirements for sorting and cleaning of waste polyester. The Japanese Teijin began to use the chemical method to produce recycled polyester products in 2002. Zhejiang Jiaren New Materials Co., Ltd. used Teijin's chemical method to produce recycled polyester. At present, China has not independently developed the industrial technology of large-scale production of recycled polyester by chemical method.

3. Recycling polyamide fiber

The polyamides are mainly polyamide 6 (PA6) and polyamide 66 (PA66). As a thermoplastic polycondensation type polymer material, a method for recycling a polyamide and a polyester have many similarities, and the recycling method can also be classified into a physical method and a chemical method.

However, unlike polyester, the characteristic functional groups of polyamides have higher reactivity, so the thermal degradation occurs more seriously when recycled by physical methods. The purity of waste is significantly higher than that of polyester, and it is not often used for miscellaneous Higher waste polyamide textiles are recycled. Also, because of the high reactivity, the depolymerization rate of polyamide is significantly higher than that of polyester, so the recycling of polyamide is often carried out by chemical methods.

BASF has conducted many years of research on polyamide depolymerization and has developed a number of methods for preparing caprolactam from PA6 waste. DuPont has developed a recycling technology PA6 and PA6 acid hydrolysis, but also can produce the corresponding high-quality polyamide monomer, and to achieve a certain scale to promote the industrialization of polyamide closed loop recycling technology. Japan Ube Industries Co., Ltd. also publicly stated that it has mastered the PA depolymerization method and the manufacturing method of PA monomer.

4. Certification of recycled components

(1) Global Recycling Standard (GRS)

This is an international, voluntary, and comprehensive product standard that addresses the implementation of product recycling/regeneration components, chain of custody, social responsibility and environmental regulations, and chemical restrictions by supply chain vendors. The three-party certification body conducts certification.

The latest updated GRS certification is a three-level system. According to the recycling standard of each product, it is divided into copper standard, silver standard and gold standard. The highest gold standard requires 95%~100% recycled materials, and silver standard products contain 70%. %—95% recycled material, while copper standard products need to contain no less than 30% recycled material.

(2) SCS Recycling Component Certification

SCS Global Services (SCS) is a provider of third-party environmental and sustainability certification. As early as 1990, SCS in the United States pioneered the world's first recycling component certification system. The company's latest version of the Kingfisher Regeneration (SCS RC) certification label has been used in textiles, carpets, packaging, construction and interior products, wood and paper, insulation, jewelry, precious metals and other industries.

The recycling component certification adopts a set of rigorous, scientific, standardized and quantitative certification steps to effectively distinguish the “pre-consumer” and “post-consumer” recycling components, comprehensively monitor the recycling product production process, effectively distinguish the recycled products from the general original products, and finally determine The amount of recycled components in the product.

(3) German Rein Recycled Material Certification

TÃœV Rheinland is a leading international technology service provider whose certification for renewable materials is based on the credibility of TÃœV Rheinland in the global end market, with audiences mainly in North America and Europe. The certification requires testing of the product to determine how much recycled material is in the product. The evaluation process includes a comprehensive review of the pre-consumption (in-production) and post-consumer (disposal) recovery ratios. This certification standard specifies the minimum proportion of recycled materials in the product. The test requirements are mainly based on ISO 14021, but higher than the ISO standard.