The technical specifications of eco-friendly yarns vary depending on fiber type, intended use, and spinning process; however, industry evaluations generally focus on the following core indicators:
Physical Properties
These include yarn fineness (count or denier), breaking strength, and elongation at break. For instance, recycled polyester yarns commonly come in specifications such as 75D, 150D, or higher; their breaking strength often approaches or matches that of virgin polyester, while elongation typically ranges from 15% to 30%, ensuring fabric elasticity and durability.
Quality Consistency
Key factors include evenness (yarn regularity), hairiness index, and twist level. Lower unevenness indicates a more uniform yarn structure and a more consistent fabric appearance. The hairiness index affects weaving efficiency and the hand-feel of the finished product; when using high proportions of recycled raw materials, process controls are required to minimize hairiness. Twist levels are adjusted based on the application-typically ranging from 300 to 900 T/m-to strike a balance between strength and hand-feel.
Functional and Eco-related Parameters
These include the proportion of recycled content, certification of the recycling source, and compliance with environmental standards. For example, GRS (Global Recycled Standard) certification generally requires a recycled content of at least 20% and full supply chain traceability, though some high-end products achieve 100% recycled fiber content. Additionally, indicators such as color fastness (typically Grade 3–4 or higher), formaldehyde content, pH value, and heavy metal residues are monitored to ensure compliance with export regulations and environmental standards.