Dye-fixing agents in chemical development

Fixing is after the dye, not instead of levelling

A dye-fixing agent improves wet fastness of anionic dyes by forming a cationic complex on the fibre or leather. In chemical development it is an after-treatment, applied after soaping or after the dye float. It will not hide unlevel dyeing, residual peroxide or residual alkali. Dyna Glycols manufactures Dyes Fixers for leather and non-formaldehyde dye-fixers in Cotton Textile-Knit/Woven Processing Chemicals. Name fibre or hide, dye class and any formaldehyde limit on the first enquiry.

A strongly cationic surface can block later anionic finish coats or prints. Grain-finished leather and pigment-printed cotton need a cautious trial. Overdose gives a harsh handle and can reduce crock or lightfastness even as wash-fastness rises.

Leather dye fixers

VENFIX DF is a cationic methylol-amide fixer for anionic dyeings, used to improve wet fastness. VENFIX NFDF is a concentrated cationic non-formaldehyde aliphatic-amine fixer. Related concentrated non-formaldehyde types are available on request. Write formaldehyde-containing versus non-formaldehyde on the purchase order; they are not interchangeable when the article has a brand formaldehyde cap.

Apply after the dye is exhausted and the float is set up for the fixer step. A cationic top on an anionic fatliquor bath can crash the emulsion if it is dumped in without a process step. Keep dye-fix and fatliquor identities separate on the order.

Textile dye-fix and related after-treatments

Cotton reactive dyeings use non-foaming soapers first, then often a non-formaldehyde dye-fixer. Anti-migration products for continuous dyeing are a different duty: they hold the dye during dry, they do not replace a fixer for wash-fastness. Nylon needs anionic fixation after acid dyes; that is not a cotton reactive fixer. Do not use a leather methylol-amide fixer in a jet without a mill trial — foam, shade and formaldehyde on the garment all change.

Printing-paste emulsifier-cum-fixers that are formaldehyde-free are print-paste articles, not exhaust dye-fixers. State print versus exhaust, and fibre, so the laboratory does not send the wrong cationic.

How to specify

Name fibre or leather article, dye class, machine, formaldehyde limit, and whether an anionic finish or print follows. Give the current fixer chemistry if you already run one. Dyna Glycols will sample a methylol-amide or a non-formaldehyde aliphatic-amine type against that after-treatment, not a leveller or a soaper.

Specification checklist

Put the application, the substrate, temperature, pH and any APEO or formaldehyde limit on the first enquiry. INCI or chemical names, cloud point, hydroxyl value, saponification value and colour are the numbers Dyna Glycols can lock on a TDS for this Dye-fixing agents topic. A warehouse nickname is not a specification.

Samples and documents

Request a laboratory sample of the related Dye-fixing agents grade together with the current SDS and TDS. The certificate of analysis is issued for the shipping lot after manufacture at Kandla SEZ. Once the trial is approved, freeze the identity tests so later drums of this chemistry match the article you evaluated.