Retention, sizing emulsion, and defoamer dose all land in the same white water. Change one without recording the other and the deposit moves rather than disappears.
One loop, four chemistries
The short white-water loop concentrates whatever the former did not retain. Fines, hydrolysed size, and surfactant residues build a deposit that looks like “dirt” to the operator. The chemistry question is which stream is unstable.
Esteem supplies sizing chemicals, defoamers, bleaching aids, and sheet-making surfactants as different product families. A white-water outbreak needs the family named. Mixing them into one tote is how mills lose sizing and gain spots.
A practical split of the brief
If Cobb or contact angle fell, start with the sizing emulsion. If the wire foams, start with the defoamer and air. If ash retention moved, start with the retention programme. If the felt is filled with adhesive, go to stickies and felt cleaning.
Write conductivity and pH on the sample request. Hard white water changes both anionic sizing packages and some defoamers.
| Observation | Likely family | Page to open |
|---|---|---|
| Size spots on the wire | Sizing emulsion stability | Sizing chemicals |
| Air in the headbox | Defoamer or mechanical air | Paper defoamers |
| Fines and ash swing | Retention and dispersion | Paper improvement |
| Tacky clothing fill | Stickies plus felt wash | Felt cleaning |
A closed loop concentrates the problem
Each trip through the saveall returns fines, dissolved starch, hydrolysed size, and whatever surfactant came in with recycled fibre or with a felt-cleaning wash. The loop gets richer. A particle that was harmless at high fresh-water use becomes a deposit once the conductivity and the temperature rise.
Surfaces matter as much as the water. Wires, uhle boxes, and approach piping offer a shear gradient where a tacky particle can anchor. The deposit you scrape off is often a mixture: organic stickies, calcium scale, and a biological film that arrived because the organic layer gave it a place to sit.
Match the chemical to the layer you can identify
A hydrophobic sticky wants a detackifier or a dispersant sized for that particle. A calcium carbonate or oxalate scale wants a different inhibitor and a hardness story. A microbiological slime wants a biocide and a housekeeping program. Applying a defoamer because the chest looks foamy does not remove the layer that is already on the metal.
EO/PO and other low-foam nonionics show up here as wash aids and as deposit-control surfactants, not as a single “machine chemical.” Ask whether the job is to keep a particle dispersed in the water or to clean a surface that is already fouled. Those are different addition points.
What to measure before the next trial
Take a deposit sample and say whether it melts, whether it dissolves in caustic, and whether it is gritty like scale. Record white-water temperature, conductivity, and pH at the addition point. A program set on a cold, open mill will drift when the loop is closed for the summer.
Change one chemical family at a time. If defoamer, detackifier, and felt wash are all moved in the same shutdown, the sheet may improve and nobody will know which lever did it.
How to Specify with Esteem
- Map dose points: retention, sizing emulsion, defoamer, and any dispersant.
- Report white-water temperature, pH, conductivity, and fines level.
- Describe the deposit: biological slime, size spots, or filler scale.
- Do not raise defoamer to fix a size-spot outbreak.
- Trial one variable per day and keep first-pass retention on the log.
Use sizing chemicals, sheet-making aids, and the defoamer table as separate line items on the request.