Recycling fiber realizes the comprehensive utilization of waste resources, and can be combined with modification technologies such as copolymerization and blending to create functional fibers with performance comparable to native products, achieving low-carbon environmental protection and environmental protection to a certain extent. Unification of high-value utilization. Last week we introduced the production process and application cases of recycled polyester fiber. This week let’s learn about recycled polyamide fiber.
100% recycled polyamide fabric
Currently, a large part of the recycled polyamide fiber on the market is made from waste silk, waste blocks, Recycling of scraps, etc. as raw materials. As a thermoplastic polycondensation polymer material, the recycling methods of polyamide have many similarities with polyester. Its recycling methods are mainly divided into physical methods and chemical methods. However, unlike polyester, the characteristic functional groups of polyamide have higher reactivity, so thermal degradation is more serious when recycling using physical methods. The purity requirements for waste materials are significantly higher than those of polyester, and it is not commonly used to treat impurities. Higher waste polyamide textiles for recycling. Also because of its high reactivity, the depolymerization speed of polyamide is significantly higher than that of polyester, so polyamide is often reused using chemical methods.
The following will introduce some research progress in polyamide recycling by relevant domestic and foreign companies.
The closed-loop recycling system for polyamide fiber developed by BASF (BASF)
BASF is using Years of research into amide depolymerization have led to the development of multiple methods for producing caprolactam from PA6 waste. In 1997, BASF established the first closed-loop polyamide fiber recycling system using a self-developed closed-loop process. The processing system can be divided into 6 steps:
①Collect waste Carpet, and confirm that the carpet is made of 100% BASF-PA6 fiber;
②Crush the product to separate the fiber and supporting material, and then separate the supporting material and other Remove non-fiber components;
③ Depolymerize the granular fibers obtained by crushing and conduct chemical distillation to reduce the polyamide to pure caprolactam monomer;
④Caprolactam is repolymerized;
⑤Polyamide is melt-spun into regenerated PA6 fiber;
⑥Make carpets from recycled PA6 fiber.
Recycled polyamide production process developed by Hengshen Group
Physics Method
The waste silk, waste blocks and scraps in the production process are crushed, melted, filtered, cooled, cut into granules and dried to obtain regenerated slices, which are then melted and spun to prepare various Specifications recycled yarn.
Chemical method
Chemical depolymerization of waste silk, waste blocks, scraps, etc. during the production process to obtain caprolactam monomer, using caprolactam to repolymerize to obtain spinning-grade chips, and then melt spinning to prepare various specifications of regenerated yarn.
Others
DuPont has developed acid hydrolysis PA66 and PA6 regeneration technology, which can produce corresponding of high-quality polyamide monomers, and has achieved a certain scale of industrial promotion of polyamide closed-loop recycling technology; South Korea’s Hyosung has launched a nylon waste product recycling process. Used nylon fishing nets are recycled into polyamide chips and then spun. Silk can eventually be made into recycled textile products, the quality of which is said to be comparable to virgin products.
</p
