China is a big country in the production and application of chemical fiber in the world. In 2019, the total output of chemical fiber in China was 58.27 million tons, including 47.51 million tons of polyester, accounting for 81.5% of the total output of chemical fiber. The problem of waste pollution associated with huge production is also becoming increasingly serious. Therefore, the development of recycled chemical fibers is an important way for China's chemical fiber industry and even the textile industry to achieve sustainable development.
1、 Latest policy requirements
Three departments including the National Development and Reform Commission: the output of recycled fiber from waste textiles will reach 2 million tons in 2025
On April 11, the Implementation Opinions on Accelerating the Recycling of Waste Textiles issued by the National Development and Reform Commission, the Ministry of Commerce and the Ministry of Industry and Information Technology put forward that by 2025, the recycling system of waste textiles will be initially established, and the recycling capacity will be greatly improved. The recycling rate of waste textiles will reach 25%, and the output of recycled fiber of waste textiles will reach 2 million tons. By 2030, a relatively complete recycling system of waste textiles will be established. Producers and consumers' awareness of recycling will be significantly improved, high-value utilization ways will continue to expand, and the level of industrial development will be significantly improved. The recycling rate of waste textiles will reach 30%, and the output of recycled fiber of waste textiles will reach 3 million tons.
In terms of promoting green and low-carbon production in the textile industry, the Opinions require promoting green textile design, encouraging the use of green fibers, and strengthening the social responsibility of textile producers. In terms of improving the recycling system of waste textiles, the Opinions require improving the recycling network, expanding recycling channels and strengthening recycling management.
2、 Introduction to Polyester Fiber
1. Polyester fiber
Polyester fiber, commonly known as "polyester". It is called "P" or "T" for short. It is a synthetic fiber obtained by spinning polyester polycondensated from organic dicarboxylic acid and diol. It is called PET fiber for short. It was invented in 1941 and is the largest variety of synthetic fibers at present.
The biggest advantage of polyester fiber is good wrinkle resistance and shape retention, and it has high strength and elastic recovery capacity. It is firm and durable, wrinkle resistant, non ironing, and non sticky.
Polyester has excellent shape setting property. The flat, fluffy or pleated form of polyester yarn or fabric after setting can remain unchanged after repeated washing in use. It is widely used in the manufacture of clothing fabrics and industrial products.
Polyester is also one of the three synthetic fibers with the simplest process and relatively cheap price. In addition, it has strong and durable, good elasticity, not easy to deform, corrosion resistance, insulation, neat, easy to wash and dry, and is loved by people.
The upstream of polyester fiber industry is petrochemical industry, and the downstream is textile industry. The main business process of the polyester industry is to purchase petrochemical products PTA, MEG and other added raw materials, conduct polycondensation reaction through corresponding production equipment, and then produce polyester filament products through spinning, adding and other processes, and sell the products to downstream weaving enterprises to produce civilian and industrial textiles, as well as the polyester fiber industry chain.
2. Application of polyester fiber
Polyester has many excellent textile properties and wearability. It can be used for a wide range of purposes. It can be pure woven, or blended with natural fibers such as cotton, wool, silk, hemp, and other chemical fibers to make wool like, cotton like, silk like, and hemp like fabrics with various patterns and colors, which are firm and scratch like, easy to wash and dry, iron free, and washable and wearable.
Polyester fabrics are suitable for men's and women's shirts, outerwear, children's clothing, interior decorative fabrics and carpets. Because polyester has good elasticity and fluffy, it can also be used as cotton wool. In industry, high-strength polyester can be used as tire cord, conveyor belt, fire water pipe, cable, fishing net, etc., as well as electrical insulation material, acid resistant filter cloth, paper making blanket, etc. The non-woven cloth made of polyester can be used for indoor decoration, carpet bottom cloth, medical industrial cloth, flocculent, lining, etc.
3、 Recycled polyester fiber
1. Classification of recycled polyester fiber
Regenerated fibers are mainly divided into two categories: regenerated cellulose fibers and regenerated synthetic fibers.
Viscose fiber is the earliest regenerated fiber, and new regenerated cellulose fibers such as Lyocell fiber, cellulose carbamate fiber, superconducting viscose fiber, kapok fiber and bamboo fiber have emerged successively.
Polyester fiber accounts for about 70% of synthetic fiber, and the application of polyester in bottle making industry is expanding rapidly. Therefore, recycled synthetic fiber is mainly recycled polyester fiber.
2. Production technology of recycled polyester fiber
At present, recycled polyester raw materials mainly come from waste PET bottle, sheet, film and polyester block and waste silk in polyester polyester production.
The preparation methods of recycled polyester fiber can be divided into physical method, chemical method and physical chemical method according to the regeneration principle.
Physical method
Physical method refers to the regeneration method of directly melt spinning waste polyester materials as raw materials after sorting, cleaning, drying and other processes.
Chemical method
Chemical method refers to the process of depolymerizing waste polyester materials into polymerization monomers or polymerization intermediates by chemical reaction, and then conducting regeneration polymerization and melt spinning after purification and separation. At present, chemical recovery technologies on the market include glycolysis, methanol decomposition and alkaline hydrolysis.
Physical chemical method
Physicochemical method is a kind of recycled chemical fiber prepared by crushing and cleaning polyester waste (waste bottles) and increasing viscosity during spinning. Physicochemical method combines the process advantages of physical recovery and chemical recovery.
4、 Recycled polyester fiber and GRS certification
Terminal enterprises must have GRS certification for recycled polyester fibers. So what is GRS certification and what are the conditions for obtaining GRS certification?
1. What is GRS certification?
The so-called GRS certificate is the abbreviation of the global recycling standard for textiles and clothing. It is a verification standard for recycled fibers established by the International Environmental Protection Management Union Certification (CU). In addition to regulating the source of raw materials, the validation standard also regulates the wastewater treatment and chemical use in the production process.
2. What are the conditions for GRS certification?
GRS certification access conditions: the proportion of renewable ingredients in certified products is ≥ 20%;
GRS logo&label use and special statement: the proportion of regeneration cost of production products ≥ 50%
Required conditions after GRS application:
If the company wants to apply for GRS certification, the upstream suppliers of recycled raw materials should also have GRS certification certificates. When the company conducts GRS certification, its suppliers should provide GRS compliance certificates (SC) and transaction certificates (TC), The supplier of the reclaimed material at the source of the supply chain shall provide the Reclaimed Material Supplier Agreement and the Reclaimed Material Declaration Form, and conduct on-site verification if necessary.
According to relevant data, Shenghong Group, Hengli Group, Shanghai Yuanfang Industry Co., Ltd., Yizheng Zhongxing Environmental Protection Technology Co., Ltd., Zhejiang Jiaren New Materials Co., Ltd., Zhejiang Haili Environmental Protection Technology Co., Ltd., Ningbo Dafa Chemical Fiber Co., Ltd. and other enterprises have successively obtained GRS certification.
5、 Recycled polyester fiber helps environmental protection
Recycled polyester fiber is a kind of recycled environment-friendly fabric developed to protect the environment in response to the national strategic development. It has a wide range of uses. It can be made into a garment, a carpet, a sofa, artificial lawn, geotextile, filter material, auto parts, etc. by using recycled polyester fiber.
The data shows that each ton of recycled products recycled can reduce 6 tons of oil consumption and 3.2 tons of carbon dioxide emissions, equivalent to the amount of carbon dioxide absorbed by 200 trees in a year. At the same time, the performance of recycled polyester fiber is equivalent to that of native fiber, and some properties are even higher than that of native fiber (such as the resilience, smoothness, fluffy degree and other indicators of recycled three-dimensional filling staple fiber) Therefore, no matter from carbon emissions, social responsibility, or resource input, the importance of recycled polyester fiber for mankind is beyond doubt.