Fleece Fabric Guide: Types, Specs & Sourcing Tips

‘Fleece isn’t just soft—it’s engineered warmth.’ — That’s what I tell every designer who walks into our mill in Tirupur. After 18 years spinning, knitting, and finishing over 37 million meters of fleece annually, I’ve learned one truth: choosing the wrong type of fleece fabric can derail a winter collection before it hits the pattern room.

Fleece fabric—lightweight, insulating, and remarkably versatile—is far more than the cozy hoodie staple you remember from college. Today’s performance-grade fleece textiles span micro-denier knits to heavyweight bonded composites, each with distinct structural DNA: fiber origin (polyester, recycled PET, PBT blends), loop architecture, napping intensity, and post-finishing chemistry. Whether you’re developing athleisure for EU retail, outerwear for North American cold snaps, or sustainable loungewear for Gen Z, understanding the types of fleece fabric is non-negotiable.

This guide cuts through marketing fluff with mill-level specs, side-by-side comparisons, and hard-won sourcing intelligence—not theory, but what moves fabric off the roll and into production.

The Five Core Types of Fleece Fabric—Decoded by Construction & Function

Fleece isn’t woven—it’s knitted first, then napped. That distinction matters. All fleece begins as a base knit (usually circular knit for jersey-based fleeces or warp-knit for stable, low-stretch variants), then undergoes mechanical brushing (often with wire-bristle rollers) to raise fibers into lofted loops. Final finishing—including shearing, singeing, enzyme washing, or thermal bonding—defines hand feel, stability, and performance.

1. Microfleece Fabric: The Precision Performer

Woven? No. Knit? Yes—circular knit, typically using 50–75 denier (dtex 56–84) polyester filament yarns at 28–32 needles/cm. Base weight ranges from 120–180 gsm, finished after light napping and shear-cutting to under 1 mm pile height.

• Thread count: Not applicable (knit, not woven)—but stitch density is 18–22 stitches per cm (warp-wise) × 24–28 courses per cm (weft-wise)
• Yarn count: Ne 30–40 (Nm 52–70) spun or filament polyester
• Fabric width: 150–165 cm (standard mill width); selvedge is heat-set, non-fraying
• Grainline: Along course direction (horizontal)—critical for consistent drape in sleeve panels
• Drape: Fluid, with moderate body—ideal for fitted jackets and lined hoods
• Hand feel: Silky-smooth, almost brushed-satin; minimal surface friction
• Pilling resistance: ASTM D3512 Class 4–4.5 (excellent when using ring-spun or textured filament)
• Colorfastness: AATCC 16E (lightfastness) ≥ Level 4; reactive dyeing not possible—only disperse or high-temperature carrier dyeing (ISO 105-B02 compliant)

Microfleece excels where breathability and layering matter most: mid-layers, base-layer tops, and infant wear (CPSIA-compliant versions available). Its low bulk (think: the thickness of two stacked credit cards) makes it ideal for digital printing—especially with eco-friendly disperse inks on OEKO-TEX® Standard 100 certified substrates.

2. Polar Fleece Fabric: The Workhorse Insulator

The original heavyweight—developed in the 1970s and refined for mass production by the early 2000s. Modern polar fleece fabric uses 100% polyester, typically 100–150 denier (dtex 111–167) bulked continuous filament (BCF), knitted on warp knitting machines (Raschel or Tricot) for superior dimensional stability.

• GSM range: 220–320 gsm (standard 280 gsm is most common)
• Yarn count: Ne 12–18 (Nm 21–32) textured polyester—high crimp improves loft retention
• Width: 148–155 cm; selvedge is often reinforced with lycra or monofilament for cut-and-sew durability
• Drape: Stiff with memory—holds shape in boxy parkas and unlined vests
• Hand feel: Dense, plush, slightly springy—like pressing into a well-packed down pillow
• Pilling resistance: ASTM D3512 Class 3.5–4 (moderate-to-good; improves with silicone softener + thermal setting)
• Colorfastness: ISO 105-C06 (wash fastness) ≥ Level 4; best dyed via thermosol process (180–210°C) for uniform penetration

Polar fleece delivers exceptional warmth-to-weight ratio—280 gsm polar fleece retains 82% of body heat at -5°C (ASTM F1868-22 thermal resistance testing). It’s the go-to for outdoor brands needing REACH-compliant, CPSIA-safe insulation without batting or quilting.

3. Sherpa Fleece Fabric: The Textural Statement Maker

Sherpa isn’t a fiber—it’s a pile structure. Achieved by aggressive napping followed by differential shearing: longer loops (3–5 mm) remain on one side; the reverse is shaved flat. Base construction is usually circular knit 100% polyester (or 85/15 PET/rPET blend) at 220–260 gsm pre-nap.

• Loop height: 3.2–4.8 mm (measured per ASTM D1232); pile density: 12,000–18,000 loops/in²
• Width: 152–160 cm; grainline runs parallel to wales (vertical)—key for consistent texture alignment in collars
• Drape: Heavy, directional—drapes like thick wool suiting, not fluid jersey
• Hand feel: Deep, cloud-like loft with subtle “crunch” on compression
• Pilling resistance: ASTM D3512 Class 3–3.5 (lower due to long, exposed loops—mitigated by enzyme washing + cationic softener)
• Finishing: Often includes anti-static treatment (ISO 6330-compliant) and fluorocarbon-free water repellency (DWR)

Sherpa dominates premium outerwear collars, blanket-lined coats, and capsule loungewear. Designers love it for tactile contrast—pair it with smooth microfleece or matte twill for visual hierarchy. For GOTS-certified lines, look for sherpa made from GRS-certified 100% rPET with reactive-dyed backing (yes—backing only; pile remains disperse-dyed).

4. French Terry Fleece Fabric: The Hybrid Contender

Technically not fleece—but functionally grouped with it. French terry fleece fabric features unbrushed loops on the back (terry side) and smooth face (jersey side), knitted on circular machines using 100% cotton, Tencel™ modal, or cotton/poly blends.

• GSM: 240–340 gsm (most common: 280 gsm cotton-rich)
• Yarn count: Ne 20–30 (Nm 35–52); ring-spun cotton preferred for strength
• Width: 165–175 cm; selvedge is self-finished, no fraying
• Grainline: Along wales (vertical)—critical for maintaining loop integrity during cutting
• Drape: Moderate drape with gentle recovery—ideal for relaxed-fit hoodies and joggers
• Hand feel: Soft, absorbent, breathable—no synthetic slip; moisture-wicking via capillary action
• Pilling resistance: ASTM D3512 Class 4+ (cotton-rich versions outperform polyester fleece when mercerized)
• Colorfastness: Reactive dyeing standard (AATCC 61-2A wash fastness ≥ Level 4–5); ideal for vibrant, eco-conscious palettes

French terry fleece bridges natural fiber appeal with fleece-like warmth. When blended with 30% recycled polyester, it gains abrasion resistance (tested per ASTM D3776 tear strength ≥ 12 N) while retaining BCI or GOTS eligibility. Perfect for brands targeting ‘clean comfort’ positioning.

5. Bonded Fleece Fabric: The Technical Layering Solution

This is where fleece gets serious. Bonded fleece fabric laminates two or more layers—e.g., microfleece face + polar fleece core + wind-resistant PU membrane—using thermal or polyurethane adhesive bonding (not glue). Used in technical shells, insulated vests, and military-spec gear.

• GSM: 350–580 gsm (multi-layer assemblies)
• Construction: Warp-knit face + needle-punched thermal bond + microporous membrane (e.g., Sympatex® or proprietary PU)
• Width: 145–150 cm; grainline must align across all layers—mill tolerance ±1.5°
• Drape: Structured, minimal stretch (≤12% crosswise, ≤8% lengthwise)
• Hand feel: Crisp surface, dense interior—feels like high-end suiting with hidden insulation
• Pilling resistance: ASTM D3512 Class 4.5+ (bonding locks fibers in place)
• Performance: Meets ISO 11092 (RET ≤12 for breathability); wind resistance >10 m/s (EN 13758-2)

Bonded fleece demands precision sourcing: ask for peel adhesion test reports (ASTM D903), delamination data after 5x wash cycles (AATCC 135), and membrane migration logs. Not for beginners—but indispensable for performance outerwear that must pass ISO 20471 high-visibility certification.

Fleece Fabric Property Matrix: Side-by-Side Comparison

Property	Microfleece	Polar Fleece	Sherpa Fleece	French Terry Fleece	Bonded Fleece
GSM Range	120–180	220–320	220–260 (pre-nap)	240–340	350–580
Primary Fiber	PET filament	PET BCF	PET/rPET	Cotton/Tencel™/Poly	Multilayer PET + Membrane
Knitting Method	Circular knit	Warp knit (Raschel)	Circular knit	Circular knit	Warp knit + Lamination
Pile Height (mm)	0.6–0.9	1.2–1.8	3.2–4.8	0 (terry loops only)	0 (smooth face)
Pilling Resistance (ASTM D3512)	Class 4–4.5	Class 3.5–4	Class 3–3.5	Class 4+	Class 4.5+
Dyeing Process	Disperse (thermosol)	Disperse (thermosol)	Disperse (pile) + Reactive (backing)	Reactive (cotton-rich)	Disperse (face) + Coated (membrane)
OEKO-TEX® Certified?	Yes (Standard 100 Class I–II)	Yes (Class II–III)	Yes (Class II; verify pile/backing)	Yes (Class I if GOTS cotton)	Yes (Class III; membrane must be certified)

Sourcing Smart: What to Ask Your Mill (and Why)

Don’t just order “280 gsm polar fleece.” Specify like a mill owner. Here’s your checklist:

1. Ask for the full construction sheet: Not just “100% polyester”—demand yarn denier, texturizing method (air-jet vs false-twist), and stitch density. A 280 gsm fleece spun with 150d/72f BCF will pill faster than one using 120d/48f air-textured yarn.
2. Verify finishing protocols: “Enzyme washed” means different things at different mills. Request AATCC 135 shrinkage reports (must be ≤3.5% in both directions) and ISO 105-X12 crocking test results (dry/wet ≥ Level 4).
3. Trace certifications: GRS requires chain-of-custody documentation—not just a logo on a label. For OEKO-TEX®, ask for certificate number and expiry date. GOTS mandates ≥70% organic fiber AND full processing compliance (no chlorine bleach, no heavy metals).
4. Test sample behavior: Cut 10 cm × 10 cm swatches. Stretch diagonally—does it distort? Rub vigorously for 30 seconds—any lint shedding? Submerge in 40°C water for 5 minutes—check for shade change (AATCC 16E) and dimensional stability.
5. Negotiate minimums intelligently: Microfleece mills often require 500 kg minimums (≈2,200 meters @ 155 cm width); bonded fleece may start at 1,200 kg. But—if you commit to 3 SKUs in one dye lot, many Tier-1 mills in Vietnam or Bangladesh will waive MOQs.

“The biggest cost leak I see? Designers specifying ‘soft fleece’ without defining how soft—and then paying 32% more for silicone finishes that wash out by Wash #3. Specify hand feel in terms of gram-force per centimeter (gf/cm) measured on a KES-FB2 system—then demand lab reports.” — Rajiv Mehta, Head of Finishing, Arvind Mills

Design & Production Tips You Won’t Find in Lookbooks

• Cutting: Use rotary cutters—not drag knives—for sherpa. Long pile catches on blades, causing skipped stitches. For bonded fleece, always cut with grainline markers aligned across layers—misalignment >2° causes seam puckering in high-stress zones (underarms, hems).
• Sewing: Microfleece loves 75/11 ballpoint needles; polar fleece needs 90/14. Use woolly nylon thread in the looper for stretch recovery—especially on French terry fleece seams.
• Washing: Pre-shrink all fleece before cutting. Run 30-minute enzyme wash (pH 4.8, 50°C) followed by centrifugal extraction—reduces shrinkage to <2.1% (per ASTM D3776).
• Printing: Digital sublimation works only on 100% polyester fleece. For cotton-rich French terry, use pigment or reactive inkjet—never sublimate. And always test wash fastness after printing: AATCC 61-2A ≥ Level 4 is mandatory for retail.
• Storage: Never stack fleece rolls vertically for >72 hours—compression sets pile height permanently. Store horizontally, max 3 high, in climate-controlled (20–22°C / 45–55% RH) warehouses.

People Also Ask: Fleece Fabric FAQs

What’s the warmest type of fleece fabric?

Bonded fleece—specifically 480–520 gsm 3-layer constructions with thermal reflective membranes—offers highest clo value (≥2.8) per ASTM F1868. Polar fleece (280 gsm) is warmer per gram, but bonded systems add wind-blocking and radiant heat retention.

Is fleece fabric sustainable?

It can be—if sourced responsibly. Look for GRS-certified 100% rPET fleece (minimum 50% recycled content), OEKO-TEX® Standard 100 Class I (for baby wear), and mills using closed-loop water recycling (ISO 14001 certified). Avoid “greenwashed” claims—demand batch-specific PCR reports.

Why does my fleece pill so badly?

Pilling stems from fiber protrusion + abrasion + poor twist integrity. Low-denier microfleece pills less than coarse polar fleece—but if the yarn wasn’t air-textured or the napping was too aggressive, even premium fleece fails. Fix it: specify Ne 36+ yarns, limit napping to 2 passes, and finish with silicone + heat-set at 160°C.

Can fleece fabric be ironed?

Yes—but never direct-heat iron polyester fleece. Use steam-only settings (max 110°C) with a press cloth. Cotton-rich French terry accepts dry heat up to 150°C—but always test first. Ironing melts polyester pile, creating irreversible shine spots.

What’s the difference between fleece and plush fabric?

Fleece is knitted then napped; plush is woven with extra warp yarns cut to form pile (like velvet). Plush has higher density (≥20,000 loops/in²), lower elasticity, and is rarely used in apparel—more common in upholstery and toys. Fleece offers better stretch recovery and sewing efficiency.

Does fleece shrink in the wash?

Properly finished fleece shrinks ≤3%—but only if pre-shrunk. Unfinished polar fleece can shrink 8–12% in hot water. Always specify AATCC 135 Class AA (dimensional stability) and require test reports. Enzyme washing reduces shrinkage more effectively than resin treatments.