What is brushing fabric? How is it different from ordinary fabric?

Raw Material Selection: The Foundation of Brushing Quality

The quality of a brushed fabric is largely determined before the process even begins. Common fiber choices include:

• Cotton: Naturally breathable; produces a soft, short pile after brushing. Widely used in flannel bedding and sleepwear.
• Polyester: Highly durable; the brushed surface resists pilling over time. The dominant choice for activewear and outdoor apparel.
• Acrylic: Mimics the look and feel of wool at a lower cost. Commonly used in faux-wool brushed jackets and blankets.
• Wool: Its natural crimp produces the finest brushed effect, though higher cost limits use to premium outerwear and coatings.

Fiber fineness also matters: microfibers in the 1.0–1.5 dtex range yield a noticeably finer, softer pile, while coarser fibers produce a rougher texture suited to industrial or heavy-duty applications.

Weaving and Knitting: Building the Right Base Structure

Before brushing can occur, the base fabric must be constructed in a way that allows fibers to be raised without destroying the cloth's integrity. Two main structures are used:

• Woven base (e.g., plain or twill weave): Provides a firm, stable structure. Twill weaves are preferred because their diagonal float lines expose more fiber length for the pins to grip.
• Knitted base (e.g., circular knit or warp knit): More elastic and lightweight. A common choice for fleece fabrics and sportswear linings.

Yarn twist is deliberately kept low during spinning — a twist factor of around 2.5–3.5 (compared to 4–5 for standard yarns) — so individual fibers are more accessible and easier to pull to the surface during raising.

Pre-Treatment: Preparing the Fabric for Raising

Before entering the brushing machine, the grey fabric undergoes several preparatory steps:

1. Singeing — A flame or heated plate briefly passes over the fabric surface to remove protruding fiber ends that would otherwise create an uneven pile.
2. Desizing and scouring — Sizing agents (starches or PVA) applied during weaving are washed out, and natural oils or wax are removed to ensure the fabric is clean and absorbent.
3. Dyeing — In many production lines, fabric is dyed before brushing so that the raised fibers and the base share a uniform color. Some manufacturers brush first and dye after for a two-tone effect.
4. Relaxing and tentering — The fabric is stretched to a consistent width on a tenter frame and allowed to relax, ensuring dimensional stability before mechanical stress is applied.

The Brushing (Raising) Process: How the Pile Is Created

This is the core manufacturing step. The fabric is fed into a raising machine — also called a napping machine — which typically features a large main drum surrounded by 24 to 36 smaller rollers, all covered with a flexible card clothing of fine bent wire pins.

How the machine works

The rollers alternate between two rotation directions relative to fabric travel:

• Pile rollers rotate in the same direction as fabric movement, lifting fibers upward.
• Counter-pile rollers rotate against fabric movement, pulling fibers back and creating a more even, tangled pile.

The fabric typically passes through the machine 4 to 8 times, with each pass gradually building up the pile height and density. Key process parameters include:

Single-Side vs. Double-Side Brushing

Not all brushed fabrics are treated on both sides. The choice depends on the end use:

• Single-sided brushing: Only the face of the fabric is raised. Common in apparel where the reverse side will be hidden or where a clean back is needed for printing. Flannel shirts and brushed denim typically use this approach.
• Double-sided brushing: Both face and back are raised. Used in blankets, heavy outerwear linings, and fleece fabric where maximum softness and insulation on both sides are required. Double-brushed fabrics can be up to 30% warmer than single-brushed equivalents at the same base weight.

Post-Brushing Finishing: Refining the Surface

After raising, the fabric undergoes additional finishing steps to achieve the desired final appearance and performance:

Shearing

Rotating blades trim the raised pile to a uniform height, typically 1–3 mm for apparel fabrics. This step gives the surface a clean, even look and is essential for products like fleece jackets and plush toys.

Emerizing

For a suede-like finish (common in peach-skin fabric), the brushed surface is further treated with emery-coated rollers that micro-abrade the pile tips, producing an ultra-fine, velvety texture.

Heat setting

Synthetic fabrics (polyester, acrylic) are passed through a stenter oven at 170–190 °C to thermally fix the pile in position, prevent shrinkage, and stabilize the fabric width.

Anti-pilling treatment

A chemical finish — often a silicone-based softener combined with an anti-pilling resin — is padded onto the surface to reduce friction between fibers during wear and laundering, extending the fabric's useful life.

Common Types of Brushing Fabric and Their Distinguishing Features

Quality Control: What Manufacturers Measure

Brushed fabric quality is assessed against several measurable standards before shipment:

• Pilling resistance: Tested via the Martindale or ICI pill box method. Apparel-grade brushed fabric typically requires a rating of 3–4 on a 5-point scale after 2,000 rub cycles.
• Pile height uniformity: Measured with a pile height gauge; acceptable variation is usually within ±0.2 mm of the target height.
• Shrinkage: After washing at 40 °C, dimensional change must not exceed 3–5% in most apparel standards (e.g., AATCC 135).
• Colorfastness: Brushed surfaces expose more dyed fiber to abrasion and light; ISO 105-X12 (rubbing) and ISO 105-B02 (light) ratings of Grade 4 or above are standard requirements for most buyers.

Sustainability Considerations in Brushing Fabric Production

The brushing process raises two significant environmental concerns. First, microfiber shedding: each brushing pass releases loose fibers into wastewater. Estimates suggest a single kilogram of polyester fleece can shed up to 1.7 grams of microplastics per wash after production, making wastewater filtration at the mill level increasingly important.

Second, energy consumption in heat-setting and drying is considerable. Leading mills have begun adopting waste-heat recovery systems that recapture up to 60% of exhaust heat from stenter ovens, reducing natural gas use substantially.

On the fiber side, recycled polyester (rPET) derived from plastic bottles is now widely used in polar fleece production. Brands such as Patagonia have reported that rPET fleece requires approximately 53% less energy to produce than virgin polyester fleece, without meaningful differences in brushing performance.