1 Fabric Handle

Fabric handle generally refers to the unique characteristics of a fabric that distinguish it from other products, including visual properties and inherent properties.

Visual properties are usually obvious and can be directly perceived by processors and end users, such as crepe stripes, small diamond shapes, pearl-like granules on the fabric surface.

Visual handle is a major component of fabric handle. Inherent handle sometimes requires inspectors or users to identify via simple tests, for example fabric hand feel and elasticity. Controlling fabric handle mainly refers to regulating various process conditions that form the fabric’s characteristic handle.

2 Crepe Fabrics

Crepe fabrics fall into two main categories. One type gets its crepe stripe effect from a special fabric weave structure. The other is weft elastic fabrics where all process conditions and methods that may generate warp crepe stripes are intentionally amplified during dyeing and finishing.

Crepe stripes on some fabrics are formed by compression; such products can also be classified as embossed fabrics. During processing of crepe fabrics, attention must be paid to all critical stages: pre-shrinking, pre-setting, dyeing, drying, and final setting.

Crepe-stripe fabrics include warp crepe fabrics and weft crepe fabrics, with warp crepe fabrics being the mainstream. Excessive shrinkage of weft yarns during processing prevents warp yarns from shrinking in unison, forming irregular streaks on the fabric surface. To preserve these streaks, weft processing tension must be minimized during production. For instance, during pre-shrinking in a jigger, nozzle pressure can be appropriately increased to raise warp tension on the fabric. In drying and final setting, higher warp tension during fabric feeding and moderately reduced setting width fully retain the warp streaks formed in preceding processes.

3 Blistered Fabrics

There are multiple ways to create blisters. Cotton fabrics can develop numerous small raised blisters on the surface through caustic soda shrinkage. Small diamond shapes or pearl-like granules can also be achieved by designing fabric weave and warp/weft density.

Different from crepe fabrics, blistered fabrics require minimizing both warp tension and weft tension throughout processing. Reduced warp tension applies to pre-shrinking, pre-setting, dyeing, drying and final setting stages.

Pure cotton poplin features distinct tiny diamonds on its finished surface. This requires proper design of warp and weft density. The coordination between warp tension and setting width in final setting also significantly affects the formation of diamond texture.

Lightweight 100% polyester pearl gauze requires minimized warp and weft tension in pre-shrinking, pre-setting, dyeing and final setting. The critical stage is drying temperature and warp tension after pre-shrinking and dyeing. Excessively high drying temperature or heavy warp tension while the fabric is hot and humid will severely damage the full pearl texture. Using loose drying equipment at low speed to preserve the full pearl effect is the key to surface texture control for blistered fabrics.

4 Calendered Fabrics

Calendering is a popular finishing process that imparts special luster to fabric surfaces. Calendering via calender machines is the primary method. Two common calendering machines are electric-heated calenders (also called schreiner calenders) and pressure calenders. Pressure calenders adopt mechanical, hydraulic or pneumatic pressurization.

Calendering creates surface luster, highlighting a luxurious fabric appearance and reflecting the wearer’s aesthetic taste and personal preference.

Major factors affecting calendering results: temperature, pressure, number of passes, speed and fabric surface smoothness. Higher temperature, greater pressure and more passes produce stronger surface shine.

Among plain, twill and satin fabrics, satin achieves the most remarkable smoothness after calendering. Compared with pure cotton staple fabrics, polyester filament fabrics show better gloss after calendering. For polyester calendered fabrics, raw material properties directly influence surface luster. Given the same denier, density and weave, FDY filaments generally have superior surface smoothness than DTY low-stretch yarns. Higher warp density also improves fabric surface gloss. Surface cleanliness before calendering directly impacts final quality. Impurities, excessive fuzz, yarn knots and uneven yarn evenness will compromise calendered results.

Overheating on electric calenders hardens the hand feel of synthetic fabrics, which requires strict control. To achieve softer luster, face-to-face fabric calendering can be adopted. The fabric flatness at the calender nip directly determines finished quality. To reduce surface defects, fabric can be tentered before entering the calender nip. Common tentering types: electric edge straighteners, spiral straight rollers and bowed rollers. For spiral straight roller tentering, roller speed and contact pressure on fabric should not be too high, otherwise scratches may occur.

Embossed Fabrics

Conventional embossing is completed on embossing machines. Electric-heated calenders can perform embossing after installing patterned rolls. Key process parameters: fabric warp tension, roll temperature and embossing speed.

Embossed fabrics are widely used for home textiles, with a small portion made into women’s apparel. Embossing is mostly carried out after final fabric setting. Maintaining durable patterns is essential. Relatively harsh process conditions are the foundation for permanent embossed patterns. When defining parameters, balance production efficiency, finished quality and fabric tolerance.

5 Napped Fabrics

Uniform napping is the core quality indicator for napped products. Common defects include napping marks, uneven pile and ground showing through. Key influencing factors: sharpness of napping clothing, rotation speed of brushing clothing, napping tension, fabric flatness on the napper, seam flatness, speed difference between main napping roll and fabric delivery speed.

Static electricity easily builds up during synthetic fiber napping, so static eliminators must be switched on. Some napped fabrics require auxiliary shearing to unify pile height. Pile length is controlled by shearing passes and the gap between shearing roll and fabric supporting roll. Fabric flatness at feeding, seam condition and equipment stability greatly affect final quality.

6 Sanded Fabrics

Sanding is widely applied to woven fabrics, while napping remains the main way to modify surface characteristics of knits. For high-count high-density pure cotton fabrics, bio-enzyme desizing after sanding is an innovative finishing technique. Both sanding and napping improve fabric surface properties and hand feel. Uniform, dense and short pile is the basic requirement for sanding. Sanding quality is affected by fabric weave, density, fiber properties, sanding method, speed, fabric flatness during processing and equipment stability.

Key Control Points for Setting

Temperature is the dominant factor determining heat-setting quality. After heat setting, wrinkle removal, surface smoothness, dimensional thermal stability and other wear performances are closely related to setting temperature.

Fabrics are heat-set to achieve specific functional properties after weaving. Heat setting stabilizes physical and chemical properties: shrinkage, width, warp & weft density tend to stay constant, and fabric surface becomes smooth. High setting temperature may cause color shift, especially for sensitive colors such as grey, army green and light khaki; color check after setting is necessary. Setting also controls fabric width, warp/weft density and shrinkage. Shrinkage control directly impacts production cost and requires close attention.

Main Process Parameters & Control

1. Padding Formula Padding liquor applied during setting. The proportion of chemicals determines hand feel, slippage and fabric color after setting.
2. Pad Roll Pressure Pad roll pressure controls liquor pick-up rate, which strongly influences fabric hand feel and color.
3. Drying Temperature Drying temperature is critical for setting quality. In resin finishing, it has great impact on dimensional stability and surface smoothness. For soft finishing, dry to touch without overheating; excessive temperature will ruin hand feel.
4. Overfeed Overfeed directly changes fabric weft density and shrinkage performance. Tension must be properly controlled during production to avoid creases and weft skew.

Setting tentering width defines final fabric width to meet technical specifications. After pre-shrinking, the width must satisfy customer requirements.

Heat-Setting Process Conditions

Heat setting is a process where fabric is held at fixed dimensions under controlled temperature and humidity, heated for a certain duration and then cooled. Core process variables: temperature, time, tension and swelling agent.

1 Temperature

Temperature is the primary factor for heat-setting quality. After heat setting, wrinkle removal, surface smoothness, dimensional thermal stability and other wear performances are closely related to setting temperature.

2 Time

Setting time is another core parameter. After fabric enters the heating zone, total time consists of four parts:

1. Heating time: time to raise fabric surface to setting temperature.
2. Heat penetration time: time for heat to reach uniform setting temperature across all fibers inside the fabric.
3. Molecular relaxation time: time for molecular chains inside fibers to rearrange under setting conditions.
4. Cooling time: time to lock fabric dimensions after exiting the oven.

Normally, setting time refers to the first three phases, excluding cooling. If phase one is regarded as preheating, setting time covers heat penetration and molecular rearrangement only. Heating and penetration time depend on heat source performance, fabric areal density, fiber thermal conductivity and fabric moisture content.

3 Tension

Tension during heat setting affects dimensional thermal stability, breaking strength and elongation at break. Warp dimensional thermal stability improves with higher warp overfeed, while weft dimensional thermal stability drops as tentering width increases. Average single yarn breaking strength slightly rises after setting; weft side shows more obvious change than warp. Fabric elongation at break decreases with wider tentering in weft direction, and rises with higher warp overfeed.

To obtain good dimensional thermal stability and wear performance, proper warp overfeed and moderate weft tentering are required. High warp tension should be avoided in pre-treatment; excessive warp elongation will force heavy weft shrinkage and require extreme tentering afterwards.

1. The number of re-folded molecular chains increases with higher heat treatment temperature.
2. Tension hinders molecular chain re-folding.
3. At very high temperatures, this hindering effect is greatly reduced.

Tension exerts remarkable influence on fiber structure, which is interrelated. Tension control is vital in all heat-setting operations.

4 Swelling Agent

Water loosens fiber structure and improves mobility of macromolecular segments. Its plasticizing effect in heat setting modifies fiber supermolecular structure and physical properties.