4

4-point inspection system

The standard for grading greige or finished fabric quality per ASTM D5430: defects score 1–4 points by length, capped at 4 per linear yard, normalized to 100 yd². Common acceptance is a typical ~≤40 points/100 yd² (strict 20–28).

See also: Right-first-time (RFT), Martindale, Pilling

Related guides: Knit Defects: Spirality, Barré and Holes — Root Cause and Control, The Whole Polyester Chain in One Table: Typical Engineering Ranges, The 4-Point Inspection System: How a Fabric Lot Gets Approved

A

Abrasion Resistance

The fabric’s resistance to wear from rubbing, usually measured by the Martindale test. Polyester’s high strength yields durable knits.

See also: Pilling, Denier, GSM (g/m²)

Related guides: Durability Science: Abrasion, Pilling and Snag, Microplastics: Fibre Shedding and Control

Air-covered yarn (ACY)

A covering yarn in which polyester filament is air-jet wrapped around an elastane (spandex) core, giving a flatter, single-step stretch yarn than twisted covering. It is used in high-recovery fabrics such as swimwear, sportswear, and shapewear.

See also: Air-jet textured yarn (ATY), DTY (Draw Textured Yarn), Intermingling (interlacing)

Related guides: DTY, ATY and ACY: Which Textured Yarn for Which Fabric

Air-jet textured yarn (ATY)

A staple-like, non-stretch yarn (Taslan type) in which a high-pressure air jet imparts loops and arcs to the filaments. Typical processing is ~7–10 bar, overfeed 5.5–36%, speed ~300–500 m/min, offering a covering, matte hand unlike DTY’s crimp-stretch.

See also: DTY (Draw Textured Yarn), Air-covered yarn (ACY), Intermingling (interlacing), False twist

Related guides: DTY, ATY and ACY: Which Textured Yarn for Which Fabric

Airflow (aerodynamic) dyeing

Low-liquor HT rope dyeing in which fabric is transported by a pressurized air stream rather than water, cutting water and energy with very low LR (typical ~1:2–1:4). The Fong’s/THEN AIRFLOW Synergy is a representative machine (typical 20–40% energy saving).

See also: Liquor ratio (LR), Disperse Dye, Zero liquid discharge (ZLD)

Related guides: Jet, Soft-Flow, Airflow: Understanding the Polyester Dyeing Machine, The Looms Behind a Roll of Polyester — A Stage-by-Stage Machinery & OEM Reference, The Water and Energy in One Kilo of Dyed Polyester Knit

Antistatic Finish

A finish or conductive-fiber treatment that reduces static buildup in synthetic fabrics. It prevents cling, sparking and dust attraction.

See also: Breathability, Heat-Setting

B

bluesign

A system that manages the whole supply chain — starting from input chemicals — for resource efficiency, chemical safety and emissions; it is process/input-focused rather than product-focused.

See also: ZDHC (Zero Discharge of Hazardous Chemicals), OEKO-TEX Standard 100

Related guides: STeP, ZDHC, Higg, bluesign: What Facility Certifications Actually Prove

Breathability

The fabric’s capacity to let air and water vapor pass through. It affects comfort and is enhanced by open structures like mesh or piqué and by wicking.

See also: Wicking, Mesh, Piqué

Related guides: Mesh and Piqué: Breathable Polyester Knits, Moisture-Wicking Finishing in Polyester Knits, Functional Finishes for Polyester Knits, Piqué, Bird’s-Eye and Mesh: The Anatomy of Breathable Polyester Knits

C

Calendering

A mechanical finishing process that passes fabric through heated rollers to flatten, smooth or add luster to the surface.

See also: Heat-Setting, Sanforizing, Raising (Napping)

Carrier Dyeing

Dyeing polyester at ~100 °C atmospheric using carrier chemicals that swell the fibre; it avoids pressurised vessels but carriers raise environmental/odour concerns.

See also: Disperse Dye, Thermosol Dyeing

Cationic-Dyeable Polyester (CDP)

Polyester modified with the SIPM comonomer to carry anionic sites, dyeable with cationic (basic) dyes; combined with regular PET it yields two-tone/heather effects.

See also: Disperse Dye, Colorfastness, Solution-Dyed (Dope-Dyed)

Related guides: Cationic-Dyeable Polyester (CDP/ECDP)

Chemical Recycling (Depolymerisation)

Breaking PET back to its monomers or intermediates (glycolysis, methanolysis, hydrolysis, enzymatic); unlike mechanical recycling it can yield virgin-equivalent quality and textile-to-textile loops.

See also: rPET (Recycled Polyester), Glycolysis, Recycled Content

CIELAB (L*a*b*)

A perceptually-oriented colour space that locates colour by lightness (L*) and two colour axes (a*, b*); the basis of colour-difference (ΔE) calculations.

See also: ΔE2000 (Colour Difference), Metamerism, Lab Dip

Colorfastness

The resistance of color to washing, rubbing, light, perspiration and similar factors. Usually rated 1–5 on a grey scale, where higher means better fastness.

See also: Disperse Dye, Sublimation Printing, Metamerism

Related guides: How Polyester Is Dyed: Disperse Dyes and HT, Color Management and Delta E in Polyester Knits, Functional Finishes for Polyester Knits, Knit Quality Testing: What to Measure in Polyester

Compactor

The finishing machine that mechanically compresses fabric lengthwise to bring residual shrinkage to commercial spec, available in tubular and open-width versions. Target shrinkage is a typical ~3–5% (premium <3%), with the steam-cylinder surface around ~140 °C.

See also: Stenter (ramöz / heat-setting frame), Dimensional Stability, Open-Width vs Tubular

Related guides: Compacting & Residual Shrinkage: How Compactors Lock In Dimensional Stability, The Looms Behind a Roll of Polyester — A Stage-by-Stage Machinery & OEM Reference

Contact Angle

The angle a water droplet makes with a surface; below 90° is hydrophilic (wets/absorbs), above is hydrophobic (repels). The core measure behind wicking and water-repellent finishing.

See also: Wicking, Durable Water Repellency (DWR), Moisture Management

Continuous polymerization (CP)

The process by which nearly all fibre-grade PET is made: PTA + MEG are esterified in continuous flow (~250–265 °C, typical) and built to target intrinsic viscosity by melt polycondensation under vacuum. It runs in either a chip (pellet) or melt-direct architecture, with a single line typically scaled at ~200–600 t/day.

See also: Purified terephthalic acid (PTA), Monoethylene glycol (MEG), Melt-direct (direct) spinning, Intrinsic Viscosity (IV)

Related guides: From PTA to Yarn: Inside a Polyester Polymer Plant, Bright, Semi-Dull, Full-Dull: Lustre Is Decided in the Polymer Plant

Course

A horizontal row of loops in a knit fabric. Courses per inch/cm indicate the lengthwise density of the fabric.

See also: Wale, Loop, Gauge

D

D/Y ratio

The ratio of friction-disc surface speed to yarn speed, the primary lever for twist and bulk in false-twist texturing. Its typical range is ~1.6–2.2; higher D/Y gives more twist and bulk, lower D/Y a flatter, more balanced yarn.

See also: False twist, DTY (Draw Textured Yarn), Set / non-set yarn

Related guides: From POY to DTY: The False-Twist Texturing Machine

Delustrant (TiO2)

A titanium-dioxide pigment added to the melt that lowers yarn luster — a property locked in at the polymer plant, not in dyeing. Typical loading is ~0% for bright, ~0.3–0.5 for semi-dull, and up to ~2% for full-dull.

See also: Continuous polymerization (CP), Spinneret, Spin finish

Related guides: Bright, Semi-Dull, Full-Dull: Lustre Is Decided in the Polymer Plant

Denier

A linear density unit equal to the weight in grams of 9,000 meters of yarn. Higher denier means a thicker/heavier filament, lower denier a finer one.

See also: Denier vs Tex, Microfiber, DTY (Draw Textured Yarn)

Related guides: Polyester Knit Basics: The Backbone of Performance, DTY Textured Yarn: Bulk, Stretch and Wicking, Recycled Polyester (rPET) in Knits, GSM Weight Guide: Choosing the Right Fabric Weight

Denier per Filament (dpf)

A yarn’s total denier divided by its filament count; it indexes fibre fineness. Below ~1.0 dpf is microfilament; lower dpf gives softer hand and denser cover.

See also: Denier, Microfiber, Denier vs Tex

Related guides: Microfilament Science: Micro- and Nano-Denier Yarns

Denier vs Tex

Both measure yarn linear density: denier is grams per 9,000 m, tex is grams per 1,000 m. Tex is the preferred SI-based unit (1 tex = 9 denier).

See also: Denier, Microfiber

Dimensional Stability

The fabric’s ability to retain its width, length and shape after washing and wear. Improved through heat-setting, sanforizing and proper yarn selection.

See also: Heat-Setting, Sanforizing, Spirality

Related guides: UPF Science: Why Polyester Shields UV Well, Durability Science: Abrasion, Pilling and Snag, What a Stenter Really Does: A Heat-Setting Guide, Compacting & Residual Shrinkage: How Compactors Lock In Dimensional Stability

Disperse Dye

A class of sparingly water-soluble dyes used to color hydrophobic synthetics like polyester. Typically applied under high temperature/pressure so the dye diffuses into the fiber.

See also: Sublimation Printing, Colorfastness, Reactive Dye

Related guides: Recycled Polyester (rPET) in Knits, How Polyester Is Dyed: Disperse Dyes and HT, Color Management and Delta E in Polyester Knits, Sustainability in Polyester Knits: Safety, Recycling, Durability

Double-Knit

A two-bed knit producing a double-layer fabric with a clean face on both sides. Structures like interlock and scuba belong to this family; it resists curling and has body.

See also: Interlock, Scuba, Single Jersey

Related guides: The Circular Knitting Machine: Single-Jersey vs Double-Jersey Architecture, OEMs and Production Ranges

Draw Ratio

The ratio by which filament is stretched after extrusion; it orients the molecular chains, raising crystallinity and tenacity while lowering elongation.

See also: POY (Partially Oriented Yarn), FDY (Fully Drawn Yarn), Spinneret

DTY (Draw Textured Yarn)

Polyester yarn that is textured by heat and twist to add bulk, stretch and softness. Widely used in knits for its loft, elasticity and coverage.

See also: FDY (Fully Drawn Yarn), Denier, Microfiber

Related guides: DTY Textured Yarn: Bulk, Stretch and Wicking, Mesh and Piqué: Breathable Polyester Knits, Moisture-Wicking Finishing in Polyester Knits, From Melt to Yarn: Melt Spinning and POY/FDY/HOY

Durable Water Repellency (DWR)

A finish that lowers surface energy so water beads up; it provides repellency, not waterproofing. A shift to PFAS-free chemistries (silicone, dendrimer) is underway. Spray test AATCC 22/ISO 4920.

See also: PFAS (Per- and Polyfluoroalkyl Substances), Contact Angle, Breathability

E

Elastane (Spandex)

An elastomeric fiber with very high stretch and recovery. Blended in small amounts into polyester knits to add stretch, shape retention and comfort.

See also: Four-Way Stretch, Scuba, Dimensional Stability

Related guides: Polyester Blends: Cotton, Elastane, Modal, With or Without Elastane? Stretch and Recovery in Polyester Knits, Naming in Polyester Knits: When One Fabric Has Many Names, Bio-Based and Alternative Polyesters: bio-PET, PTT, PBT

Evaporative Resistance (Ret)

A fabric’s resistance to sweat vapour (m²Pa/W); lower Ret means more breathable. Measured per ISO 11092 and used to grade breathability classes.

See also: Thermal Resistance (Rct), Breathability, Moisture Management

F

False twist

The heart of DTY production: POY is simultaneously drawn and twisted then heat-set, after which the twist runs back out, leaving a permanent crimp memory. The texturing unit may be a friction-disc stack, magnetic pin, or crossed belt, with a typical texturing speed of ~600–1,200 m/min.

See also: DTY (Draw Textured Yarn), POY (Partially Oriented Yarn), D/Y ratio, Set / non-set yarn

Related guides: From POY to DTY: The False-Twist Texturing Machine, DTY, ATY and ACY: Which Textured Yarn for Which Fabric

FDY (Fully Drawn Yarn)

Fully drawn flat filament polyester yarn with a smooth, lustrous surface. Compared to DTY it gives a sleeker, less bulky and shinier hand.

See also: DTY (Draw Textured Yarn), Denier

Related guides: DTY Textured Yarn: Bulk, Stretch and Wicking, From Melt to Yarn: Melt Spinning and POY/FDY/HOY, POY, FDY, HOY: The Filament Spinning Line and Its Speed Regime, Why Polyester Filament Loves the Water-Jet Loom

Feeder

The point on a circular knitting machine that delivers yarn to the needles per revolution; the number of feeders sets productivity (courses per turn). A typical 30-inch machine has ~48–120 feeders (~1.6–4/inch), and more feeders means higher output.

See also: Positive yarn feed, Gauge, Stitch length (loop length)

Related guides: Gauge, Stitch Length and GSM: How Fabric Weight Is Set on the Knitting Machine, The Circular Knitting Machine: Single-Jersey vs Double-Jersey Architecture, OEMs and Production Ranges

Fleece

A knit whose surface is napped/raised into a soft, air-trapping pile. Polyester fleece provides lightweight, warm and fast-drying insulation.

See also: Raising (Napping), GSM (g/m²), rPET (Recycled Polyester)

Related guides: GSM Weight Guide: Choosing the Right Fabric Weight, Fleece and Scuba: Structured Polyester Knits, Brushed, Unbrushed and Fleece: Where Warmth Comes From in Polyester Knits, The Weight Map: Which Knit Goes Where, from 80 to 400 g/m²

Four-Way Stretch

Fabric that stretches and recovers in both the width and length directions. Common in elastane-blended polyester knits for freedom of movement and fit.

See also: Elastane (Spandex), Scuba, Dimensional Stability

Related guides: Polyester Blends: Cotton, Elastane, Modal, With or Without Elastane? Stretch and Recovery in Polyester Knits, Rib, Interlock and Ponte: Choosing the Right Double-Face Knit, Bio-Based and Alternative Polyesters: bio-PET, PTT, PBT

G

Gauge

The number of needles per inch on a knitting machine, defining knit fineness. Higher gauge gives a fine, dense knit; lower gauge a coarse, open one.

See also: Course, Wale, Single Jersey

Related guides: Single Jersey vs Interlock: Choosing a Polyester Knit, Gauge, Stitch Length and GSM: How Fabric Weight Is Set on the Knitting Machine, The Circular Knitting Machine: Single-Jersey vs Double-Jersey Architecture, OEMs and Production Ranges

Glycolysis

A chemical-recycling route in which PET is broken down with excess glycol to the BHET monomer; one of the most mature depolymerisation methods.

See also: Chemical Recycling (Depolymerisation), rPET (Recycled Polyester)

Godet

A driven roller that conveys, draws, and sets the speed/temperature regime of the yarn in the spinning line; in FDY, heated godets perform inline drawing and heat-setting. Typical FDY godet temperatures are GR1 ~65–90 °C and the draw godet ~108–130 °C.

See also: FDY (Fully Drawn Yarn), POY (Partially Oriented Yarn), Quench (cooling), Spin finish

Related guides: POY, FDY, HOY: The Filament Spinning Line and Its Speed Regime, Why Polyester Filament Loves the Water-Jet Loom

Greige

Unfinished knit fabric that has not yet been dyed, bleached or finished. It is the intermediate product awaiting dyeing and finishing.

See also: Heat-Setting, Disperse Dye, Sanforizing

Related guides: PET Polymer Chemistry: IV, Polycondensation and Why It Matters, Tubular or Open-Width? The Take-Down Route and Why It Matters

GRS (Global Recycled Standard)

An international standard certifying recycled content, supply-chain traceability and social/environmental criteria. Commonly required for rPET products.

See also: rPET (Recycled Polyester), Recycled Content, OEKO-TEX Standard 100

Related guides: Polyester Recycling: Mechanical and Chemical Routes, The Standards Map: GRS, RCS, OEKO-TEX, bluesign, ZDHC

GSM (g/m²)

The weight of fabric per square meter in grams. It is the primary measure of a knit’s thickness and density; low GSM means light/thin, high GSM means heavy/thick fabric.

See also: Denier, Interlock, Fleece

Related guides: Single Jersey vs Interlock: Choosing a Polyester Knit, GSM Weight Guide: Choosing the Right Fabric Weight, Fleece and Scuba: Structured Polyester Knits, Knit Quality Testing: What to Measure in Polyester

H

Hand-Feel

The overall subjective tactile quality of a fabric, including softness, drape, smoothness and stretch. Shaped by fiber fineness and finishing.

See also: Microfiber, Modal, Calendering

Related guides: Microfilament Science: Micro- and Nano-Denier Yarns

Heat-Setting

A process that stabilizes synthetic fabric with controlled heat to lock in dimensions, width/weight and shape stability. It reduces shrinkage and spirality.

See also: Dimensional Stability, Spirality, Sanforizing

Related guides: Polyester Knit Basics: The Backbone of Performance, Fleece and Scuba: Structured Polyester Knits, How Polyester Is Dyed: Disperse Dyes and HT, Knit Quality Testing: What to Measure in Polyester

Higg MSI (Materials Sustainability Index)

A life-cycle-based tool scoring the cradle-to-gate environmental impact of materials (water, energy, carbon, chemistry); used for comparison.

See also: Life Cycle Assessment (LCA), Recycled Content

Hollow Fibre

A fibre with a hollow core; the trapped air boosts thermal insulation and lightens the fibre. Used in thermal fills and insulating layers.

See also: Trilobal Cross-Section, Loft, Spinneret

Hollow-conjugate fibre

A hollow-cross-section polyester staple with permanent helical crimp (often siliconized, HCS), delivering high bulk, recovery, and insulation. It is used in pillow, duvet, and fill applications, with typical fineness ~6–20D.

See also: Polyester staple fibre (PSF), Stuffer-box crimp, Tow

Related guides: Before the Yarn: How Polyester Staple Fibre (PSF) Is Made

I

Interlock

A double-knit structure made of two interlocked rib fabrics, smooth on both faces. It yields a thick, stable, low-curling and substantial fabric.

See also: Single Jersey, Rib, Double-Knit

Related guides: Single Jersey vs Interlock: Choosing a Polyester Knit, GSM Weight Guide: Choosing the Right Fabric Weight, Fleece and Scuba: Structured Polyester Knits, With or Without Elastane? Stretch and Recovery in Polyester Knits

Intermingling (interlacing)

Air-jet locking of filaments at periodic knot points — a mechanical, non-chemical cohesion that preserves yarn integrity in winding, weaving, and knitting. Typical levels are NIM ~0–10, SIM ~40–60, and HIM ~100–120+ knots/m.

See also: False twist, DTY (Draw Textured Yarn), Spin finish, Air-jet textured yarn (ATY)

Related guides: From POY to DTY: The False-Twist Texturing Machine

Intrinsic Viscosity (IV)

A measure (dL/g) representing PET’s molecular weight. Higher IV means longer polymer chains and higher tenacity; textile filament is typically ~0.62–0.66 dL/g (ASTM D4603).

See also: Polycondensation, Solid-State Polymerisation (SSP), rPET (Recycled Polyester)

Related guides: From PTA to Yarn: Inside a Polyester Polymer Plant, The Whole Polyester Chain in One Table: Typical Engineering Ranges

Islands-in-Sea Fibre

A conjugate-spinning technique where two polymers are spun together and dissolving the 'sea' frees ultra-fine 'island' microfilaments; used for ultra-microfibres and suede-like surfaces.

See also: Microfiber, Denier per Filament (dpf)

J

Jacquard

A knitting technique where needles are individually selected to create complex patterns, colors or textures. It enables multi-color, figurative or structural designs.

See also: Interlock, Gauge, Piqué

L

Lab Dip

A small dyed fabric swatch prepared in the lab to match a target color. Submitted to the customer for color approval before bulk production.

See also: Metamerism, Colorfastness, Disperse Dye

Related guides: Cationic-Dyeable Polyester (CDP/ECDP), The Disperse Dyeing Process: HT/HP, Thermosol and Carrier, What Really Sets MOQ and Lead Time: Dye-Lot Math

Life Cycle Assessment (LCA)

A method that systematically quantifies a product’s environmental impacts from raw material to end of life (ISO 14040/14044); the basis of carbon-footprint and water/energy claims.

See also: Higg MSI (Materials Sustainability Index), Solution-Dyed (Dope-Dyed), Recycled Content

Liquor ratio (LR)

The ratio of water mass to fabric mass in the dye bath — the single biggest lever on water, energy, and chemical consumption. Old jets run 1:15–1:20, modern soft-flow ~1:5–1:8, low-LR rope ~1:3.7–1:5, and airflow ~1:2–1:4 (typical).

See also: Airflow (aerodynamic) dyeing, Disperse Dye, Zero liquid discharge (ZLD), Right-first-time (RFT)

Related guides: Jet, Soft-Flow, Airflow: Understanding the Polyester Dyeing Machine, The Whole Polyester Chain in One Table: Typical Engineering Ranges, The Water and Energy in One Kilo of Dyed Polyester Knit, What Really Sets MOQ and Lead Time: Dye-Lot Math

Loft

The thickness, bulk and air-trapping capacity of a fabric. Increased by textured yarn and raising; it provides insulation and a soft hand.

See also: Fleece, DTY (Draw Textured Yarn), Raising (Napping)

Related guides: Fibre Cross-Section Engineering: Trilobal, Hollow, Multi-Channel, Thermophysiological Comfort: Ret, Rct and the Sweating Hot Plate

Loop

The fundamental structural unit of knit fabric: a stitch formed by interlooping yarn. The arrangement of loops defines the fabric’s structure and stretch.

See also: Course, Wale, Single Jersey

M

Martindale

A method measuring a fabric’s abrasion (ISO 12947) and pilling (ISO 12945-2) resistance by rubbing the sample against a standard abradant; results as rub counts or a 1–5 grade.

See also: Abrasion Resistance, Pilling

Related guides: Ring, Rotor, Vortex and Compact: Spun Polyester Yarn Systems and Pilling

Mass Balance

A chain-of-custody model where recycled/sustainable input is allocated to products by accounting rather than physical segregation; reading a claim correctly requires knowing the method.

See also: GRS (Global Recycled Standard), RCS (Recycled Claim Standard), Recycled Content

Related guides: The Standards Map: GRS, RCS, OEKO-TEX, bluesign, ZDHC

Melt-direct (direct) spinning

The lowest-cost mega-producer route in which continuous-polymerization melt is fed straight to the spinning heads without pelletizing, skipping the re-melt step of the chip route. It is the architecture favoured by mega-scale integrated plants (Hengli/Tongkun type), with a single CP line at a typical ~30–2,000 t/day.

See also: Continuous polymerization (CP), Spinneret, POY (Partially Oriented Yarn), FDY (Fully Drawn Yarn)

Related guides: From PTA to Yarn: Inside a Polyester Polymer Plant, From Chip to Cloth: The Value Chain and Where the Margin Sits

Mesh

An open, porous knit with visible holes. Its high airflow and fast drying make it popular for sportswear and linings.

See also: Breathability, Wicking, Single Jersey

Related guides: Mesh and Piqué: Breathable Polyester Knits, Piqué, Bird’s-Eye and Mesh: The Anatomy of Breathable Polyester Knits, Naming in Polyester Knits: When One Fabric Has Many Names

Metamerism

When two colors match under one light source but differ under another. A color-matching issue controlled through dye selection and standardized light booths.

See also: Lab Dip, Colorfastness, Disperse Dye

Related guides: Reductive Clearing, Oligomers and Wash Fastness

Microfiber

Yarn made of extremely fine filaments, typically under 1 denier. It delivers a soft hand, high surface area, good moisture transport and coverage.

See also: Denier, Wicking, DTY (Draw Textured Yarn)

Related guides: Polyester Knit Basics: The Backbone of Performance, DTY Textured Yarn: Bulk, Stretch and Wicking, Recycled Polyester (rPET) in Knits, Moisture-Wicking Finishing in Polyester Knits

Microfibre Shedding

Microscopic fibre fragments released from fabric during washing and wear; staple and cut-edge constructions shed more than filament. Measured by the ISO 4484 series.

See also: Microfiber, Pilling, Abrasion Resistance

Modal

A soft, breathable regenerated cellulose fiber made from beech wood pulp. Often blended with polyester for a more natural hand and moisture management.

See also: Breathability, Microfiber

Related guides: Polyester Blends: Cotton, Elastane, Modal

Moisture Management

The overall performance of a fabric in absorbing, transporting and evaporating sweat. In polyester knits it is optimized via wicking, fiber cross-section and finishing.

See also: Wicking, Breathability, Microfiber

Related guides: Bio-Based and Alternative Polyesters: bio-PET, PTT, PBT, Thermophysiological Comfort: Ret, Rct and the Sweating Hot Plate, The Physics of Moisture Transport: Capillarity and MMT, Antimicrobial and Odor-Control Chemistry

Moisture Management Tester (MMT)

An instrument (AATCC 195) that measures liquid spreading on both faces of a fabric, producing indices such as wetting time, absorption rate, one-way transport and OMMC.

See also: OMMC (Overall Moisture Management Capacity), Wicking, Moisture Management

Monoethylene glycol (MEG)

PET’s second main monomer, which esterifies with PTA to form the BHET oligomer and then the polyester chain. The reaction typically runs at a MEG:PTA ratio of ~1.1–1.2:1, with excess glycol recovered during polycondensation.

See also: Purified terephthalic acid (PTA), Continuous polymerization (CP)

Related guides: From PTA to Yarn: Inside a Polyester Polymer Plant, From Chip to Cloth: The Value Chain and Where the Margin Sits

O

OEKO-TEX Standard 100

An independent testing and certification system certifying that textiles are free of harmful substances. It sets limit values for hazardous chemicals.

See also: ZDHC (Zero Discharge of Hazardous Chemicals), GRS (Global Recycled Standard), Colorfastness

Related guides: Recycled Polyester (rPET) in Knits, How Polyester Is Dyed: Disperse Dyes and HT, Color Management and Delta E in Polyester Knits, Functional Finishes for Polyester Knits

OEKO-TEX STeP

A six-module system that certifies a production FACILITY, not a product (chemical management, environment, wastewater, health & safety, social responsibility, quality management). It underpins the facility condition of the MADE IN GREEN label and is weighed alongside ZDHC and bluesign in buyer due-diligence.

See also: ZDHC (Zero Discharge of Hazardous Chemicals), GRS (Global Recycled Standard), OEKO-TEX Standard 100, Zero liquid discharge (ZLD)

Related guides: STeP, ZDHC, Higg, bluesign: What Facility Certifications Actually Prove

Oligomer

Short-chain cyclic by-products of PET that can migrate to the fibre surface at high temperature, causing white specks and fastness issues.

See also: Reductive Clearing, Disperse Dye

Related guides: Reductive Clearing, Oligomers and Wash Fastness

OMMC (Overall Moisture Management Capacity)

The single-number summary of an MMT test, computed from bottom-face absorption rate, one-way transport and spreading speed. Ranges 0–1; higher is better.

See also: Moisture Management Tester (MMT), Wicking

Open-Width vs Tubular

Whether knit fabric is processed as a seamless tube or slit into flat open-width. Open-width affects cutting efficiency and dyeing/finishing evenness.

See also: Greige, Calendering, Spirality

Related guides: Tubular or Open-Width? The Take-Down Route and Why It Matters

P

PBT (Polybutylene Terephthalate)

A fast-crystallising polyester that dyes under atmospheric conditions and is elastic; often used for stretch (elastane-like) effects in blends and hosiery.

See also: PTT (Polytrimethylene Terephthalate), Four-Way Stretch

PFAS (Per- and Polyfluoroalkyl Substances)

A family of fluorine-based chemicals resistant to water and oil and persistent in the environment; once standard in textile DWR, now being phased out by regulation.

See also: Durable Water Repellency (DWR), OEKO-TEX Standard 100, ZDHC (Zero Discharge of Hazardous Chemicals)

Pilling

Small balls of tangled fibers that form on the fabric surface from abrasion. Because polyester is strong the pills cling stubbornly; reduced via yarn quality and finishing.

See also: Microfiber, Raising (Napping), Colorfastness

Related guides: Polyester Knit Basics: The Backbone of Performance, Polyester Blends: Cotton, Elastane, Modal, Knit Quality Testing: What to Measure in Polyester, Sustainability in Polyester Knits: Safety, Recycling, Durability

Piqué

A knit structure with a textured raised waffle/honeycomb surface. Common in polo shirts, it offers good breathability and dimensional stability.

See also: Single Jersey, Breathability, Wicking

Related guides: Mesh and Piqué: Breathable Polyester Knits, Moisture-Wicking Finishing in Polyester Knits, Piqué, Bird’s-Eye and Mesh: The Anatomy of Breathable Polyester Knits, Naming in Polyester Knits: When One Fabric Has Many Names

Polycondensation

The condensation polymerisation in which PTA and MEG build long PET chains while releasing water/glycol; run in the melt phase with a catalyst (e.g. Sb₂O₃).

See also: Intrinsic Viscosity (IV), Solid-State Polymerisation (SSP)

Polyester staple fibre (PSF)

Polyester fibre cut to defined lengths (32/38/51/64 mm) rather than left as filament, spun into staple (spun) yarn by ring/rotor/vortex or used in nonwovens. It is made via a five-stage chain (melt-spin → tow → draw → crimp → cut), with apparel fineness at a typical ~1.0–1.5 dpf.

See also: Tow, Stuffer-box crimp, Hollow-conjugate fibre, Stitch length (loop length)

Related guides: Before the Yarn: How Polyester Staple Fibre (PSF) Is Made, Ring, Rotor, Vortex and Compact: Spun Polyester Yarn Systems and Pilling, Where the World’s Polyester Actually Comes From: Producers and the Value Chain

Positive yarn feed

Delivering yarn to the knitting machine at a constant, metered rate (from storage drums), required for constant stitch length, consistent GSM, and prevention of barré/tension faults. Memminger-IRO, BTSR, and LGL are typical suppliers in this field.

See also: Feeder, Stitch length (loop length), Gauge

Related guides: Gauge, Stitch Length and GSM: How Fabric Weight Is Set on the Knitting Machine, The Circular Knitting Machine: Single-Jersey vs Double-Jersey Architecture, OEMs and Production Ranges, Knit Defects: Spirality, Barré and Holes — Root Cause and Control

POY (Partially Oriented Yarn)

An intermediate filament polyester yarn not yet textured or fully drawn. It is the feedstock for producing DTY and FDY.

See also: DTY (Draw Textured Yarn), FDY (Fully Drawn Yarn), Denier

Related guides: From Melt to Yarn: Melt Spinning and POY/FDY/HOY, POY, FDY, HOY: The Filament Spinning Line and Its Speed Regime, Where the World’s Polyester Actually Comes From: Producers and the Value Chain, Turkey’s Polyester and Knit-Dye Industry: Upstream Depth, Clusters and the Structural Moat

PTT (Polytrimethylene Terephthalate)

A polyester made from 1,3-propanediol, optionally partly bio-based; its kinked molecular structure gives inherent stretch, softness and good recovery.

See also: PBT (Polybutylene Terephthalate), Elastane (Spandex), Four-Way Stretch

Purified terephthalic acid (PTA)

One of PET’s two main monomers, produced by oxidation of paraxylene (PX) and esterified with MEG to build the polyester chain. The typical MEG:PTA feed ratio is ~1.1–1.2:1; in Turkey, SASA’s Adana plant (~1.75 Mt/yr, Koch Technology P8++) is the country’s largest PTA source.

See also: Monoethylene glycol (MEG), Continuous polymerization (CP), Intrinsic Viscosity (IV)

Related guides: From PTA to Yarn: Inside a Polyester Polymer Plant, From Chip to Cloth: The Value Chain and Where the Margin Sits, Turkey’s Polyester and Knit-Dye Industry: Upstream Depth, Clusters and the Structural Moat

Q

Quench (cooling)

The spinning step in which molten filaments leaving the spinneret are rapidly solidified by an air stream, where filament diameter and orientation are set. For microfilament, radial quench (e.g. Oerlikon EvoQuench) uses typically 60–80% less process air than cross-flow.

See also: Spinneret, Spin finish, Godet, POY (Partially Oriented Yarn)

Related guides: POY, FDY, HOY: The Filament Spinning Line and Its Speed Regime

R

Raising (Napping)

A finishing process where wire-covered rollers lift surface fibers into a soft, fuzzy nap. It creates the hand of fleece and brushed fabrics.

See also: Fleece, Terry, Pilling

Raschel

The multi-bar (4–~78 bars) class of warp knitting, producing lace, mesh, nets, and double-needle-bar 3D spacer fabrics. The KARL MAYER RD/HighDistance series are typical DNB raschel machines (~700–850 courses/min).

See also: Tricot, Spacer fabric (3D)

Related guides: Beyond Circular Knitting: Warp Knitting and Weaving, Tricot or Raschel? A Warp-Knit Selection Guide, Warp Knitting’s Hidden Superpower: 3D Spacer Fabric

RCS (Recycled Claim Standard)

A standard that verifies the recycled content share in a product along the chain; unlike GRS it carries no social/environmental criteria, certifying content only.

See also: GRS (Global Recycled Standard), Recycled Content, Mass Balance

Reactive Dye

A dye class that forms covalent bonds with cellulosic fibers (cotton, modal). In polyester/cotton blends it is used to dye the cotton component.

See also: Disperse Dye, Modal, Colorfastness

Recycled Content

The percentage by weight of a product derived from recycled material. Verified through standards like GRS and forming the basis of sustainability claims.

See also: rPET (Recycled Polyester), GRS (Global Recycled Standard), Greige

Related guides: Solution-Dyed (Dope-Dyed) Polyester, Bio-Based and Alternative Polyesters: bio-PET, PTT, PBT, Polyester Recycling: Mechanical and Chemical Routes, The Standards Map: GRS, RCS, OEKO-TEX, bluesign, ZDHC

Reductive Clearing

Removing excess surface dye after disperse dyeing with a reducing bath (e.g. sodium hydrosulphite); it raises wash and rub fastness.

See also: Colorfastness, Disperse Dye, Oligomer

Related guides: Reductive Clearing, Oligomers and Wash Fastness

Rib

A knit structure of alternating knit and purl wales that gives high widthwise stretch. Used for cuffs, collars and waistbands.

See also: Interlock, Wale, Four-Way Stretch

Right-first-time (RFT)

The share of dye lots that hit the target shade on the first attempt without redyeing — the real determinant of dyehouse economics. Redyeing roughly doubles a lot’s water/energy/chemical/machine occupancy, so ~90%+ RFT is structurally cheaper than ~70%.

See also: Lab Dip, Liquor ratio (LR), Disperse Dye, 4-point inspection system

Related guides: From Chip to Cloth: The Value Chain and Where the Margin Sits, The Water and Energy in One Kilo of Dyed Polyester Knit, What Really Sets MOQ and Lead Time: Dye-Lot Math

rPET (Recycled Polyester)

Polyester yarn made mainly from recycled PET bottles or textile waste. It offers performance similar to virgin polyester while reducing environmental footprint.

See also: GRS (Global Recycled Standard), Recycled Content, Greige

Related guides: Recycled Polyester (rPET) in Knits, Sustainability in Polyester Knits: Safety, Recycling, Durability, PET Polymer Chemistry: IV, Polycondensation and Why It Matters, Polyester Recycling: Mechanical and Chemical Routes

S

Sanforizing

A compacting finish that pre-shrinks fabric mechanically to minimize shrinkage in later washes. It improves dimensional stability.

See also: Dimensional Stability, Heat-Setting, Calendering

Scuba

A double-knit with a thin foam-like inner layer giving body and slight stretch. Known for its smooth surface and shape-retaining structure.

See also: Interlock, Four-Way Stretch, Elastane (Spandex)

Related guides: Fleece and Scuba: Structured Polyester Knits

Set / non-set yarn

A DTY choice governed by the second (set) heater: a 'set' yarn with second heat-setting at ~160–180 °C is stable and soft, while a 'non-set' yarn (no second heater) is high-stretch and high-torque. It drives the fabric’s stretch, hand, and twist-liveliness.

See also: False twist, DTY (Draw Textured Yarn), D/Y ratio

Related guides: From POY to DTY: The False-Twist Texturing Machine, Jet, Soft-Flow, Airflow: Understanding the Polyester Dyeing Machine

Shrinkage

The dimensional loss of fabric after washing or heat, usually measured as a percentage. Polyester shows low shrinkage and is controlled via heat-setting.

See also: Dimensional Stability, Heat-Setting, Sanforizing

Related guides: Compacting & Residual Shrinkage: How Compactors Lock In Dimensional Stability

Single Jersey

The basic weft-knit made on one needle bed, with knit loops on the face and purls on the back. Light, stretchy and economical but prone to edge curling.

See also: Interlock, Loop, Spirality

Related guides: Single Jersey vs Interlock: Choosing a Polyester Knit, GSM Weight Guide: Choosing the Right Fabric Weight, With or Without Elastane? Stretch and Recovery in Polyester Knits, Rib, Interlock and Ponte: Choosing the Right Double-Face Knit

Solid-State Polymerisation (SSP)

Heating PET chips below melting under vacuum or nitrogen to raise molecular weight (IV); used to restore IV for bottle, technical and rPET grades.

See also: Intrinsic Viscosity (IV), rPET (Recycled Polyester), Chemical Recycling (Depolymerisation)

Solution-Dyed (Dope-Dyed)

A method where pigment is added to the melt before spinning, locking colour inside the fibre; it gives superior light/wash fastness and large water-energy savings, at the cost of a minimum order per colour.

See also: Colorfastness, Disperse Dye, Life Cycle Assessment (LCA)

Spacer fabric (3D)

A three-dimensional fabric in which two face fabrics are bound by perpendicular monofilament pillars, knitted on double-needle-bar raschel — something neither weaving nor weft knitting can do. The typical gap is ~2–15 mm, offering breathability, pressure distribution, and insulation.

See also: Raschel, Tricot

Related guides: Beyond Circular Knitting: Warp Knitting and Weaving, Tricot or Raschel? A Warp-Knit Selection Guide, Warp Knitting’s Hidden Superpower: 3D Spacer Fabric

Spin finish

An oil–water emulsion applied to the filament right after quench that reduces friction, provides antistatic protection, and holds the filaments together. It safeguards yarn processability through the later godet, texturing, and knitting steps.

See also: Quench (cooling), Godet, False twist

Related guides: POY, FDY, HOY: The Filament Spinning Line and Its Speed Regime

Spinneret

The metal plate whose many fine holes extrude molten polymer into filaments; hole shape sets the fibre cross-section (round, trilobal, hollow).

See also: Trilobal Cross-Section, Hollow Fibre, Draw Ratio

Related guides: POY, FDY, HOY: The Filament Spinning Line and Its Speed Regime

Spirality

A defect in knits (e.g. single jersey) where loop slant causes seams to twist sideways. Controlled through yarn twist and proper heat-setting.

See also: Single Jersey, Heat-Setting, Dimensional Stability

Related guides: Single Jersey vs Interlock: Choosing a Polyester Knit, Knit Quality Testing: What to Measure in Polyester, With or Without Elastane? Stretch and Recovery in Polyester Knits, Rib, Interlock and Ponte: Choosing the Right Double-Face Knit

Stenter (ramöz / heat-setting frame)

The main finishing machine that fixes fabric width, GSM, and dimensional stability and sets performance chemistry (via padder). For PET, typical heat-setting is ~180–210 °C / 20–60 s; Monforts Montex and Brückner Power-Frame are representative OEMs.

See also: Compactor, Heat-Setting, Dimensional Stability, Disperse Dye

Related guides: Tubular or Open-Width? The Take-Down Route and Why It Matters, What a Stenter Really Does: A Heat-Setting Guide, The Looms Behind a Roll of Polyester — A Stage-by-Stage Machinery & OEM Reference

Stitch length (loop length)

The length of yarn forming one knit loop — the main setting that, with gauge and yarn count, determines GSM, to which it is inversely related. In single-jersey knitting the typical stitch length is ~2.1–2.9 mm, kept constant by positive feed.

See also: Gauge, Positive yarn feed, Feeder, GSM (g/m²)

Related guides: Gauge, Stitch Length and GSM: How Fabric Weight Is Set on the Knitting Machine

Stuffer-box crimp

The PSF step in which drawn tow is compressed into a box to gain saw-tooth crimp and then heat-set, the crimp being needed for fibre cohesion and bulk in staple spinning. It is applied just before cutting to fix the crimp memory.

See also: Tow, Polyester staple fibre (PSF), Hollow-conjugate fibre

Related guides: Before the Yarn: How Polyester Staple Fibre (PSF) Is Made

Sublimation Printing

A digital/transfer printing method where disperse dye turns from solid to gas under heat/pressure and bonds permanently into polyester fibers. Yields vivid, wash-durable prints.

See also: Disperse Dye, Colorfastness, Microfiber

Related guides: How Polyester Is Dyed: Disperse Dyes and HT, Color Management and Delta E in Polyester Knits, The Disperse Dyeing Process: HT/HP, Thermosol and Carrier

T

Terry

A knit with uncut loop piles on the surface (loopback). Absorbent, soft and lofty, it is used for sweatshirting and towel-like fabrics.

See also: Fleece, Raising (Napping), Loop

Thermal Resistance (Rct)

A fabric’s resistance to dry heat flow (m²K/W); higher Rct means warmer. Measured on a sweating hot plate per ISO 11092.

See also: Evaporative Resistance (Ret), Breathability, Loft

Thermosol Dyeing

A continuous disperse-dyeing method where dye is padded, dried and then fixed at ~190–215 °C; used for high throughput.

See also: Disperse Dye, Carrier Dyeing, Sublimation Printing

Tow

In PSF production, the thick continuous bundle formed by gathering thousands of melt-spun filaments, on which drawing, crimping, and cutting are performed. The typical draw ratio is ~3:1–4:1, after which the bundle is cut to staple length.

See also: Polyester staple fibre (PSF), Stuffer-box crimp, Hollow-conjugate fibre

Related guides: Before the Yarn: How Polyester Staple Fibre (PSF) Is Made

Tricot

The fine, smooth class of warp knitting, typically using 2–4 guide bars, producing stable, run-resistant fabrics for linings, swimwear, shapewear, and mesh. The KARL MAYER HKS series (E28–E50, ≤~4,400 rpm) is the reference machine.

See also: Raschel, Spacer fabric (3D), Open-Width vs Tubular

Related guides: Beyond Circular Knitting: Warp Knitting and Weaving, Tricot or Raschel? A Warp-Knit Selection Guide

Trilobal Cross-Section

A three-lobed (Y-shaped) fibre cross-section that reflects light directionally for a silk-like lustre and hides soil. Common in carpet and lustrous apparel.

See also: Spinneret, Hollow Fibre, Hand-Feel

U

UPF (UV Protection Factor)

The degree to which a fabric blocks ultraviolet radiation. Increased by dense knit, dark color and UV finishes; a sought-after property in polyester performance wear.

See also: GSM (g/m²), Disperse Dye

Related guides: UPF Science: Why Polyester Shields UV Well

W

Wale

A vertical column of loops in a knit fabric. Wales per inch/cm indicate the widthwise density of the fabric.

See also: Course, Loop, Rib

Wicking

The fabric’s ability to move moisture (sweat) to the surface by capillary action for fast drying. A core function of polyester knits in performance and sportswear.

See also: Breathability, Microfiber, Piqué

Related guides: Polyester Knit Basics: The Backbone of Performance, DTY Textured Yarn: Bulk, Stretch and Wicking, Polyester Blends: Cotton, Elastane, Modal, Mesh and Piqué: Breathable Polyester Knits

Z

ZDHC (Zero Discharge of Hazardous Chemicals)

A compliance program aiming to eliminate hazardous chemical use and discharge in textile manufacturing. Governed by a Manufacturing Restricted Substances List (MRSL).

See also: OEKO-TEX Standard 100, GRS (Global Recycled Standard), Disperse Dye

Related guides: The Standards Map: GRS, RCS, OEKO-TEX, bluesign, ZDHC, STeP, ZDHC, Higg, bluesign: What Facility Certifications Actually Prove

Zero liquid discharge (ZLD)

A system in which practically all dyehouse wastewater is recovered and discharge is reduced to a solid/salt residue, adding evaporator and crystallizer stages on top of membrane recovery (UF/NF/RO). It demands high thermal energy and cost, with unit costs being study-dependent / representative.

See also: Liquor ratio (LR), Airflow (aerodynamic) dyeing, OEKO-TEX STeP, ZDHC (Zero Discharge of Hazardous Chemicals)

Related guides: STeP, ZDHC, Higg, bluesign: What Facility Certifications Actually Prove, The Water and Energy in One Kilo of Dyed Polyester Knit

Δ

ΔE2000 (Colour Difference)

The current formula (CIEDE2000) computing perceptual difference between two colours on CIELAB; lightness, chroma and hue weightings make it closer to the eye. Typical acceptance is around ~1 depending on the product.

See also: CIELAB (L*a*b*), Metamerism, Lab Dip