Recycled & Sustainable Knitwear Yarns: Technical Guide for Eco-Friendly OEM Production

What Counts as Sustainable or Recycled Yarn?

Sustainable knitwear yarns fall into four core categories:

• Recycled fibers (mechanical/chemical recycling)

• Low-impact natural fibers (organic cotton, RWS wool)

• Regenerated cellulose fibers (modal, lyocell, bamboo viscose)

• Eco-optimized blends designed for performance and circularity

Important certifications include:

• GRS (Global Recycled Standard)

• RCS (Recycled Claim Standard)

• GOTS (Organic Cotton)

• RWS (Responsible Wool Standard)

• Oeko-Tex Standard 100

• Bluesign® chemistry compliance

Brands increasingly require complete chain-of-custody documentation, making certified yarn sourcing essential.

Recycled Polyester (rPET)

Fiber Origin & Processing

rPET is made from post-consumer PET bottles or post-industrial scrap, re-processed into new filament or staple fibers.

Key Technical Characteristics

• High durability

• Very low shrinkage

• Excellent colorfastness

• Good pilling resistance

• Ideal for 7GG–16GG production

• Perfect for large-volume programs

Ideal Applications

• School uniforms

• Corporate sweaters

• Mass-market basics

• Polo knits

• Eco-friendly athletic knitwear

• rPET/cotton blended collections

Recycled Cotton

Why Brands Use It

• Significant waste reduction

• Lower water impact

• Soft, breathable feel

• Strong sustainability storytelling

Factory Challenges

Recycled cotton fibers are shorter and weaker.

Expect:

• Higher pilling

• Lower durability

• Limited color performance

• Reduced suitability for fine gauges (12GG–18GG)

Best Applications

• 3GG–7GG sweaters

• Casual tops

• Eco kidswear

• Recycled cotton fashion capsules

Blending with polyester, viscose, or nylon greatly improves performance.

Recycled Wool & Recycled Cashmere

Characteristics

• Lower cost than virgin fibers

• Shorter staple length

• Slightly rougher hand-feel

• Often limited to heather colors

Factory Considerations

• Higher pilling risk

• Requires higher yarn twist

• Works best in 3GG–7GG bulky styles

• Controlled washing is essential

Product Applications

• Heavy sweaters

• Winter accessories

• Sustainable luxury collections

• Recycled wool fashion capsules

Brands often blend recycled and virgin cashmere for improved softness.

Organic & Low-Impact Natural Fibers

Organic Cotton (GOTS)

• No pesticides or synthetic fertilizers

• High market demand

• Ideal for kidswear and women’s basics

• Perfect for spring/summer knitwear

Linen & Hemp

• Low water use

• Naturally breathable

• Excellent for summer textured knits

• Usually blended with cotton or viscose

RWS Wool

• Ethical animal welfare

• Sustainable land management

• Preferred by premium winter brands

Regenerated Sustainable Fibers (Modal, Tencel, Bamboo)

Viscose (Rayon)

• Soft and drapey

• Affordable

• Requires careful shrinkage control

Modal

• More stable than viscose

• Smooth surface

• Perfect for 12–18GG women’s knits

Tencel™ Lyocell

• Closed-loop chemical system (highly eco-friendly)

• Natural antibacterial properties

• Stronger than viscose

• Ideal for luxury eco sweaters and tops

Bamboo Viscose

• Soft and breathable

• Affordable option for eco collections

• Sustainability depends on certification

Eco-Optimized Yarn Blends

rPET/Cotton Blends

• Lower shrinkage

• Good durability

• Perfect for commercial knitwear

Recycled Wool/Nylon

• Improved strength

• Less pilling

• Suitable for rugged winter sweaters

Tencel/Cotton

• Cool, breathable, smooth

• Ideal for summer knits

Viscose/Nylon

• Common in fine women’s knitwear

• Excellent stitch clarity

• Strong elasticity and recovery

Manufacturing Challenges with Sustainable Yarns

Lower Tensile Strength

Shorter fibers (recycled cotton/wool) break more easily.
Factory solution: Increase twist, add reinforcement fibers.

Shrinkage Instability

Modal, viscose, and bamboo shrink more aggressively.
Factory solution: Pre-shrink panels, gentle washing, controlled agitation.

Color Limitations

Recycled fibers, especially wool and cotton, often produce heather shades only.

Higher Pilling

Short fibers = more surface fuzz.
Factory solution: anti-pilling finishing, blended yarns, higher twist count.

Applications for Sustainable Knitwear Programs

Eco Fashion Collections

• Tencel sweaters

• Recycled cotton tops

• rPET winter knitwear

Premium Sustainable Brands

• RWS wool pullovers

• Modal/tencel fine gauge sweaters

• Recycled cashmere accessories

Corporate & School Uniform Programs

rPET provides stability, durability & compliance.

High-Volume Retailers

Sustainable materials support brand ESG & annual sustainability KPIs.

OEM/ODM Workflow for Sustainable Fiber Knitwear

Yarn Sourcing & Documentation

• GRS/RCS certificates

• Lot traceability

• Supplier inspection

Sampling Stage

• Pilling test

• Shrinkage test

• Colorfastness

• Hand-feel evaluation after wash
  Lead time: 3–7 days.

Bulk Production Controls

• Gauge adjustment for fiber softness

• Stable machine tension

• Temperature control during finishing

Finishing & QC

Includes:

• Low-temperature washing

• Softening treatments

• Anti-pilling processing

• Steam blocking

• Final measurements

QC follows ISO standards for shrinkage, colorfastness, and pilling.