ISO 9001 is not only a fundamental quality assurance tool but also an important threshold for accessing high-end market customer qualifications. Deeply embedding the system requirements into the entire weft knitting production process—establishing procedural documents and closed-loop mechanisms from yarn source control to finished product shipment—is the key to effective system implementation

In today’s textile industry, which is accelerating its transition toward low carbon, the use of recycled fibers has moved from being a “nice-to-have” to a “must-have” for companies competing in the global market. GRS (Global Recycled Standard), established by the international non-profit organization Textile Exchange, is one of the world’s most authoritative certification systems for recycled materials. This certification not only strictly verifies the recycled content of products but also requires companies to establish a fully traceable system covering raw material procurement, production processes, and finished product delivery, while setting quantitative standards for environmental protection, chemical management, and social responsibility. GRS-certified yarns are typically made from post-consumer recycled PET bottles (e.g., waste cola bottles) and recycled textiles. Compared with virgin polyester, recycled polyester (rPET) can reduce the carbon footprint by approximately 70% per ton. Industry estimates suggest that if a textile company fully adopts GRS-certified recycled polyester fiber for knitting yarn, carbon emissions can be reduced by about 40% at the raw material stage alone. The global market for recycled fiber fabrics for apparel is forecast to grow from US$13.7 billion in 2025 to US$25.4 billion by 2032, at a compound annual growth rate of approximately 9.19%. In terms of sportswear brands, Li Ning’s 2025 ESG report showed that its annual usage of recycled polyester yarn reached 4,715 tons, cumulatively recycling about 380 million waste plastic bottles. Adidas has committed to achieving 100% recycled polyester by 2025, and the sustainable material procurement ratios of brands such as Nike and Anta are also increasing year by year. More importantly, over 60% of mainstream global apparel brands now use GRS certification as a hard threshold for supplier procurement; companies without certification risk being excluded from core supply chains. In industry practice, Fuen Co., Ltd. starts at the source, primarily using GRS-certified recycled polyester fiber and eco-friendly viscose fiber, combined with color spinning technology to reduce energy consumption and emissions in dyeing and finishing. Through customised intelligent production lines and the use of green energy sources such as solar power and biomass fuels, the company has built a full‑chain green production system from raw material to finished product. Its products are now sold in Europe, America, and Southeast Asia, and it has established long‑term partnerships with internationally renowned brands such as Uniqlo, H&M, and ZARA. Zhongwang Fabric uses GRS-certified eco‑friendly DTY yarn made from recycled waste cola bottles through high‑tech recycling technology, achieving resource circularity at the source. Supplemented by rooftop photovoltaic power generation and waste heat recovery from RTO exhaust treatment units, the company has been recognized as a provincial‑level green and low‑carbon factory. Xinyuanhui Technology has built a closed‑loop model of “recycling – remanufacturing – certification”, processing over 50,000 tons of recycled polyester raw material annually, reducing carbon emissions by approximately 120,000 tons, with certification covering all production stages: weaving, dyeing and finishing, grey fabric, and colored fabric. Zhongshan Guotai Dyeing & Finishing regards GRS certification as a key tool for securing international orders – each batch of recycled fabric comes with a dedicated yarn “ID card”. Its water reuse rate reaches 30%, saving 174,000 tons of water annually. Using GRS-certified yarn at the raw material source means that from the moment of creation, the product carries a traceable “green identity”. Behind each product lies the rebirth of waste plastic bottles, a significant reduction in carbon footprint, and a fully transparent and verifiable green commitment across the entire chain. From raw material selection to weaving and processing, from environmental certification to brand cooperation, this commitment embodies the philosophy of “weaving a green future with technology”. Guided by the “dual carbon” goals, GRS certification is not only an environmental mark for products but also a crucial step for companies to fulfill their social responsibilities and move toward sustainable development. When every yarn carries the concept of resource circularity, green and energy-saving measures are no longer just slogans – they become measurable, verifiable results, truly paving a green and sustainable development path from raw material to finished garment.

In the field of weft‑knitted fabrics, elasticity has always been a core indicator of quality and wearing comfort. Traditionally, fabric elasticity relies mainly on spandex‑core or wrapped yarns. However, spandex has clear drawbacks – it tends to degrade after repeated washing, exposure to sunlight, or contact with chlorine and high temperatures. Wearers often find that after many wears and washes, areas such as knees and elbows become loose, baggy, and deformed. Moreover, spandex’s elasticity declines with repeated stretching and over time – a phenomenon known as “elastic fatigue.” These pain points have driven the industry to seek an alternative solution that provides durable elasticity without the need for spandex. The emergence of Sorona® yarn offers a fundamental solution to the above problems. DuPont™ Sorona® is a revolutionary bio‑based polymer (PTT fiber). Its key technology is that 37% of its raw materials come from annually renewable plant resources – 1,3‑propanediol (PDO) produced by fermenting corn sugar, which is then polymerized with terephthalic acid. This gives Sorona® significant environmental benefits: compared with petroleum‑based nylon, its production process reduces petroleum resource consumption by 37%, energy use by 44%, and greenhouse gas emissions by 59%. In terms of performance, Sorona®’s unique molecular structure (a “Z‑shaped” conformation) gives it spring‑like elastic deformation capability, and this conformational change is reversible – the fiber returns to its original shape when the external force is removed. Specifically, Sorona® yarn provides 15–20% natural stretch, with an elastic recovery rate of over 92% at 300% elongation, achieving comfortable stretch and shape retention without relying on spandex. Unlike spandex, Sorona®’s elasticity comes from the fiber’s molecular structure itself, not from an external sheath. Therefore, it does not easily lose elasticity after repeated washing and stretching, and its shape retention is significantly better than that of traditional spandex fabrics. What is more noteworthy is that Sorona® is naturally well‑suited to the weft‑knitting process. Weft knitting machines form loop structures by the knitting action of needles in the horizontal direction, which requires the yarn to have good flexibility and dimensional stability. Sorona® yarn combines a soft hand feel (close to cotton, with a silky smoothness), excellent color fastness (can be dyed at atmospheric pressure and boiling temperature), and wrinkle‑free, easy‑care properties, making it run smoothly and efficiently on circular weft knitting machines. In practical development, companies can use 100% Sorona® yarn to weft‑knit naturally stretchable jersey fabrics, or blend Sorona® with cotton, modal, viscose, and other fibers in different ratios to develop various fabric structures such as plain and interlock on single‑knit or double‑knit machines. Industry practice shows that weft‑knitted fabrics made from Modal/Sorona blended yarn on circular knitting machines exhibit good elastic recovery, low shrinkage, and a smooth, soft hand feel, making them suitable for high‑end applications such as T‑shirts, baby wear, and underwear. From an industry trend perspective, “ammonia‑free stretch” has become an important innovation direction in textiles. Since Sorona® introduced the “ammonia‑free stretch” concept in the Chinese market in 2012, it has gradually moved from being unknown to being adopted in high‑end professional segments such as sportswear, casual wear, and outdoor gear, and has established long‑term partnerships with industry leaders like Anta. In July 2025, the industry held a dedicated “No Stretch Without Fabric, New Elasticity Without Ammonia” seminar on the development of ammonia‑free elastic fabrics, exploring the broad application prospects of non‑spandex elastic fibers such as Sorona® stretch composite yarns in sportswear, yoga wear, outdoor equipment, and more. In summary, using Sorona® yarn as a weft‑knitting raw material – with its plant‑based bio‑origin, durable mechanical elasticity endowed by its spring‑like molecular structure, and excellent compatibility with the weft‑knitting process – has truly ushered in a new era of ammonia‑free stretch fabric. It achieves fabric elasticity that can “stretch out and spring back,” enabling weft‑knitted fabrics to have long‑lasting, comfortable stretch and outstanding shape retention without depending on spandex.