Fabric Chemistry | NOSK Life

Advanced Technical Reference

Fabric Chemistry

Fibre polymers, dye classes, chemical finishing, restricted substances, and wet-process control.

Fabric Chemistry

01

Fibre Chemistry

Fibre polymer structure controls moisture response, dye affinity, heat behaviour, chemical resistance, and finishing potential.

Cellulosics contain hydroxyl groups and readily absorb moisture
Protein fibres are sensitive to alkali, chlorine, and excessive heat
Polyester is hydrophobic and commonly dyed with disperse dyes
Nylon contains amide groups and accepts acid dyes
Acrylic is commonly dyed with cationic dyes
Elastane requires protection from chlorine, heat, and aggressive processing

02

Dye Classes and Fixation

Dye selection must match fibre chemistry, shade, fastness target, process route, and restricted-substance requirements.

Reactive dyes form covalent bonds with cellulosics
Vat dyes offer high wash fastness after reduction and oxidation
Disperse dyes diffuse into polyester under heat
Acid dyes bond ionically with wool, silk, and nylon
Pigments require a binder and sit mainly on the surface
Unfixed dye must be removed by correct rinsing and soaping

03

Chemical Finishing

Finishes alter hand, appearance, durability, moisture behaviour, repellency, flame response, or biological performance.

Softener selection affects hydrophilicity and yellowing
Crosslinking resins improve crease recovery but may release formaldehyde
Enzymes remove surface fibre under controlled pH and temperature
DWR chemistry requires curing and should meet current PFAS restrictions
Wicking finishes increase capillary transport on synthetics
Finish compatibility must be validated with prints, coatings, and elastane

04

Safety and Restricted Substances

Chemical management links input control, worker safety, wastewater, and finished-product compliance.

Screen inputs against ZDHC MRSL and buyer chemical policy
Test products against buyer RSL and destination laws
Control restricted aromatic amines from azo colorants
Monitor formaldehyde, phthalates, metals, APEOs, and organotins where relevant
Maintain SDS, labels, secondary containment, PPE, and spill response
Never mix incompatible acids, alkalis, oxidizers, and reducers

05

Process Control and Troubleshooting

Stable chemistry requires controlled concentration, liquor ratio, pH, temperature, time, water quality, and mechanical action.

Patchy shade: check circulation, migration, dosing, and pretreatment
Poor fixation: verify pH, salt/alkali profile, time, and temperature
Low rubbing grade: improve wash-off and surface dye removal
Yellowing: review heat, antioxidants, softener, and packaging
Finish failure: verify pickup, wetting, concentration, drying, and cure
Strength loss: reduce oxidation, enzyme severity, alkali, or processing time

Apply buyer-specific manuals where requirements are stricter.