Syntans by function
WET END - SYNTANS (Liquids) and WET END - SYNTANS (Powders) are not one chemistry. Neutralising syntans buffer so grain does not blow. Acrylic retans fill and tighten with good lightfastness. Acidic acrylics plump in acid media. Phenolic replacement syntans include white/bleaching grades. Melamine and dicyandiamide resins fill empty parts and help buffing. Rechroming syntans keep chrome character on wet-blue. Dye-levelling syntans disperse vegetable and resin tannins.
Write the function on the purchase order: rechrome, neutralize, replace, resin-fill, white, or dye-level. Melamine-formaldehyde resins should be flagged if the article has a formaldehyde limit.
Fatliquors
Fatliquirs lubricate collagen after tannage. Anionic synthetics, vegetable-oil concentrates, sulphited fish-oil types, weakly anionic pastes, and cationic or non-ionic tops are different tools. Lightfast synthetics suit whites and anilines. Sulphited fish-oil types give fluffy milled garment. Cationic tops on an anionic fat bath can crash the emulsion if they are dumped in without a process step.
The VENOL liquor and VENSOFT families are specified by ionic type, water or active content, and % on shaved weight — not by another supplier’s fatliquor code.
Dye fixers after the dye
Dyes Fixers are cationic after-treatments for anionic dyeings. Formaldehyde-containing methylol-amide types and non-formaldehyde aliphatic-amine types both exist. A strongly cationic surface can block later anionic finish coats, so grain-finished articles need a cautious trial.
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 Leather topic. A warehouse nickname is not a specification.
Samples and documents
Request a laboratory sample of the related Leather 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.