Fleece Fabric: The Warm Core of Winter Apparel

Fleece fabric is a cornerstone of modern cold-weather apparel, balancing plush softness with dependable insulation. From heavy-weight hoodies to jackets and accessories, fleece delivers warmth, durability, and comfort that appeals equally to consumers and apparel developers. This guide explains how fleece is made, which certifications ensure quality, and how sourcing teams can specify and care for it effectively.

What Is Fleece?

In textiles, fleece refers to a fabric with a napped, brushed pile interior designed to trap air and create insulation. Though the term once described sheep’s wool, today it covers synthetic and blended knits used widely across fashion, sportswear, and outdoor gear.

Origins and Evolution

Modern synthetic fleece emerged in the late 1970s, when Malden Mills (now Polartec) introduced “Synchilla,” a polyester pile knit that revolutionized outerwear. By making the technology publicly available, fleece quickly became the standard for warmth-to-weight efficiency in apparel.

Why Choose Heavy-Weight Fleece

• Thermal insulation: Raised pile traps warm air against the body.
• Soft comfort: Plush nap offers a cozy, premium hand-feel.
• Lightweight warmth: Retains heat with less mass than wool.
• Quick drying: Hydrophobic fibers shed moisture and dry rapidly.

Fiber Types and Construction

Common Fiber Choices

• Polyester fleece: Most common, durable, and cost-efficient.
• Recycled polyester fleece: Uses post-consumer PET bottles; certified under the Global Recycled Standard.
• Cotton or cotton-blend fleece: Smooth outer surface, soft brushed inside — ideal for sweats.
• Specialty blends: Incorporate TENCEL™, hemp, or modal for sustainability and texture.

How Fleece Fabric Is Made

1. Knit or weave the base fabric (usually heavy gauge knit).
2. Brush or raise one or both sides to form the plush pile.
3. Heat-set to stabilize loft and reduce shrinkage.
4. Apply finishes: anti-pill, water-repellent, or antimicrobial coatings.

Fabric Weight and Performance

Weight (g/m²)	Use	Performance
100–150	Micro-fleece base layers	Light, breathable, minimal insulation
200–250	Mid-layer hoodies, vests	Balanced warmth and flexibility
300 +	Heavy-weight jackets	High insulation, reduced breathability

Popular Variants

• Polar fleece: Synthetic classic for outdoor use.
• Microfleece: Lightweight and packable.
• Sherpa fleece: Curly, deep pile resembling shearling.
• French terry fleece: Smooth-looped interior, often cotton-rich.

Performance Benefits

• Warmth-to-weight efficiency: High loft equals high insulation.
• Durability: Maintains structure through many wash cycles.
• Easy care: Machine-washable and wrinkle-resistant.
• Affordability: Lower cost than wool or down while maintaining warmth.

Considerations and Sustainability

Standard fleece is not inherently wind- or water-proof. Many outerwear brands combine it with membranes or laminated shells for weather resistance. Additionally, attention to sustainability is vital: synthetic fleece can shed microfibers during washing. A UC Santa Barbara study found that a single fleece jacket may release hundreds of thousands of fibers per wash, underlining the importance of recycled inputs and closed-loop systems.

To mitigate impact, brands now prioritize OEKO-TEX® certified and bluesign® System approved mills — ensuring chemical safety and environmental accountability throughout production.

Certifications and Standards

Certification	Scope	Purpose
OEKO-TEX® Standard 100	Tests for harmful substances	Ensures skin-safe fabrics
Global Recycled Standard (GRS)	Recycled content and chain of custody	Verifies sustainability claims
bluesign® System	Chemical management framework	Reduces environmental footprint
ISO 9001 / 14001	Quality / environmental systems	Supports consistent production

For additional reference, explore our Materials & Fabrics for Clothing Production page for certified textile sourcing insights.

How to Source and Specify Heavy-Weight Fleece

Specification Checklist

• Define GSM and pile height (e.g., ≥ 300 g/m² for outerwear).
• Choose fiber composition (100% PET, recycled, or cotton blend).
• Specify finish: anti-pill, water-repellent, antimicrobial.
• Confirm colorfastness and shrinkage tolerance.
• Document certifications and lab test data in your tech pack.

Supplier Vetting Steps

• Request mill test certificates: GSM, pilling, air-permeability.
• Verify certification numbers via Textile Exchange or OEKO-TEX database.
• Assess brushing quality and uniform pile height.
• Confirm MOQs and lead times (heavy fleece often requires higher minimums).

Sampling and Production

• Create fabric swatches and prototype garments before bulk approval.
• Conduct wash tests for loft retention and pilling resistance.
• Optimize cutting tools and seam finishes to handle bulk.
• Perform full QC: color, nap uniformity, hand-feel consistency.

Material Care and End-Consumer Guidance

Care Instructions

• Wash inside-out in cold water with mild detergent.
• Avoid fabric softeners and high-heat tumble drying.
• Air-dry or tumble on low; store folded to preserve loft.
• Use a depilling comb as needed — preventive finishing is best.

Communicating Care in Brand Messaging

Proper care extends product lifespan and reduces microfiber shedding, reinforcing both durability and sustainability. Clear care labeling supports customer trust and decreases returns — a measurable business benefit.

Comparison: Fleece vs. Other Warm Fabrics

Fabric	Warmth	Weight	Breathability	Typical Use
Heavy-weight fleece	High	Medium-High	Good	Hoodies, jackets
Wool melton	High	High	Moderate	Formal outerwear
Down fill	Very high	Low	Variable	Technical jackets
Softshell knit	Medium	Medium	High	Transitional layers
Cotton fleece	Medium	Medium	High	Loungewear

FAQs About Certifications and Standards

What makes OEKO-TEX Standard 100 important for fleece?
It ensures the finished fabric is free from harmful levels of chemicals such as formaldehyde and heavy metals, safeguarding skin comfort and safety in daily wear.

Why should recycled fleece carry the GRS mark?
The Global Recycled Standard verifies the recycled content and tracks it through the entire supply chain, preventing false sustainability claims.

How does bluesign® improve production standards?
The bluesign® System ensures controlled chemical input and wastewater safety, minimizing environmental impact during fleece manufacturing.

FAQs About Sourcing and Production

What GSM is recommended for heavy-weight fleece hoodies?
For outerwear and hoodies intended for cold conditions, aim for 300 g/m² – 350 g/m² fleece with a dense nap for optimum warmth.

Which tests confirm fleece quality?
Request lab reports for pilling resistance, colorfastness, shrinkage, and air permeability to ensure consistent performance across batches.

How can brands improve sustainability in sourcing?
Partner with certified mills, prioritize recycled or blended fibers, and require documentation from recognized bodies such as OEKO-TEX and GRS.

FAQs About Materials and Care

How do you wash fleece without damaging it?
Use cold water and mild detergent, skip softeners, and dry on low heat to maintain loft and softness.

Why does fleece pill, and how can it be prevented?
Pilling occurs when fibers break and tangle; selecting anti-pill finishes and quality yarns significantly reduces surface wear.

Can fleece be recycled after use?
Yes, polyester fleece can be mechanically or chemically recycled depending on infrastructure. Recycled fleece further supports a circular textile economy.

Conclusion

Heavy-weight fleece remains one of the most versatile materials in apparel manufacturing — plush, reliable, and now increasingly sustainable. For sourcing teams and designers, combining certified materials with informed production practices ensures both product quality and environmental responsibility.

If your brand plans to develop new collections using certified fleece fabrics for hoodies, jackets, or accessories, connect with our team to discuss sustainable material options and production timelines via the request form.