Textile Washing Agents and Oil Stain Removers

After a reactive dyeing, the dye that never bonded stays on the cloth; leave it there and wet fastness drops and the shade bleeds on the first wash. The same group covers spin finish, grease and handling stains. Eight families, 23 products.

Why wash after a reactive dyeing?

Reactive dye forms a covalent bond with the fibre, but part of the dye in the bath reacts with water instead. That hydrolysed dye can no longer bond; it stays on the cloth held only physically. Dried down, the shade looks right. It bleeds on the first wash.

The job of a washing-off agent is to lift that unfixed dye off the surface and keep it from coming back. The second half is harder than the first: once stripped, the dye is free in the liquor, and on dark shades at a short liquor ratio it redeposits on the cloth. That is back-staining, and it takes wet fastness down directly.

Is a washing-off agent the same as a detergent?

No. A household detergent emulsifies soil and holds it in suspension. The core function of a reactive washing-off agent is dispersion and dye binding: keeping the stripped dye molecule in the water and off the fabric. Most of them are therefore low-foaming and formulated to work in hard water.

Why must oil stains come off before dyeing?

Spin finish, sewing machine grease and mineral oil picked up in handling are all hydrophobic. The dye liquor cannot reach the spot, so it dyes lighter than the ground around it. Strip the stain after dyeing and the remover takes some dye with it, which leaves a permanent mark.

The rule is simple: oil stains come off in pre-treatment, and no later than before dyeing. Singeing and heat-setting both fix oil into the fibre, so intervening ahead of those two steps matters in particular. A heat-set oil stain usually cannot be removed at all.

Solvent-based or solvent-free?

Solvent-based products work faster on heavy mineral oil because they dissolve the oil first and emulsify it afterwards. The price is odour, flash point and the risk of clashing with a customer's restricted substance list.

Solvent-free products rely on a surfactant blend. On the same stain they normally want more time or a higher temperature, but they are easier on the effluent and on shop-floor safety. Terpene-based natural products sit between the two: strong solvency, noticeable odour.

Per-product dosage and temperature are given on each product page: pending from the client.

When does the machine get washed?

Going from a dark shade to a pale one, after a strongly coloured trial, and before any long shutdown. A machine cleaning agent removes the dye-and-oil film that builds up in the jet pipe and on the heating surfaces. Left in place, that film transfers into the next batch as a stain, and the cause is usually looked for in the recipe instead.