Colloidal silica for paper and board
Paper mills, converters and box plants use colloidal silica in three ways. As a transparent anti-slip coating, it stops stacks and reels from sliding. As a microparticle, it improves retention and drainage on the paper machine. In coated papers, it improves gloss and ink receptivity.
1. Anti-slip coating
A thin coat of colloidal silica raises the coefficient of friction of the paper surface without changing its appearance. The film is transparent. Typical uses:
- Kraft liner and corrugated boxes. Palletised loads stay stable in storage and in transit.
- Paper reels. Less telescoping when reels are wound and unwound.
- Office and copier paper, paper bags and sacks. Sheets feed reliably, and filled sacks stack without sliding.
The sol can be applied by size press, spray, or roll coater on the converting line. Two types are used:
| Type | Charge | Typical choice when… |
|---|---|---|
| Alkaline colloidal silica (CH83-1) | Negative | The line runs at neutral to alkaline pH and the coating contains no cationic additives |
| Acidic colloidal silica | Negative (acidic pH) | The line runs acidic, or residual alkali must be kept low |
2. Retention and drainage (microparticle systems)
In the wet end, colloidal silica is used together with cationic starch or a cationic polymer. The polymer bridges fibres, fines and filler. The negatively charged silica particles then re-flocculate these into small, tight flocs. The result is better retention of fines and filler, faster drainage, and good sheet formation. Dosages are low, and every furnish is different, so microparticle programmes are always optimised on the machine.
We supply the silica component to mills and to retention-programme formulators. Send us your current silica specification and we will propose a grade for a trial.
3. Coated and inkjet papers
In coated papers, colloidal silica improves surface strength and gloss. In inkjet papers, the coating usually has to be cationic so that it fixes the anionic dyes in the ink. See inkjet receptive coatings for the cationic systems we supply.
Frequently asked questions
How does colloidal silica make paper anti-slip?
Does an anti-slip coating affect printing or gluing?
Should I use an alkaline or acidic colloidal silica?
Do you supply colloidal silica for retention and drainage programmes?
Need the full TDS or a trial sample?
Tell us your application and target spec. Our technical team replies within one working day.