Pregelatinized Tapioca Starch for Paper Manufacturing

Starch is one of the highest-volume non-fibre raw materials in papermaking. It is used to build dry strength, to bind pigments in coatings, and to modify the surface of the sheet so it performs in printing and converting. Tapioca starch is valued for its clean, neutral character and its film-forming behaviour.

Pregelatinized tapioca starch — pregel starch — is specifically relevant where the solution has to be made up in cold water. Because it has already been cooked and dried, viscosity develops in the mixing vessel without a jet cooker or batch cooking system.

Surface sizing starch is applied to the formed sheet at the size press or film press. It consolidates surface fibres, reduces porosity and improves surface strength, which affects printing behaviour and runnability in converting.

The practical constraints are solution solids and viscosity at the application temperature: the solution must be fluid enough to be applied evenly and to give the intended pick-up. Cold-water make-up removes the cooking stage from this loop, which is where pregelatinized grades are commonly considered.

In coating formulations starch acts as a binder or co-binder, holding pigment particles to each other and to the base sheet. Its contribution is to the rheology and water retention of the coating colour as well as to the bond itself, so any change in starch affects how the colour runs on the coater.

Compatibility with the pigment system and with synthetic binders should be assessed in the laboratory before a mill trial, using the actual coating colour recipe.

Wet-end starch is added to the furnish before the sheet is formed and contributes to dry strength and to the retention of fines and fillers. Its effectiveness depends on the charge environment of the system, the addition point and the rest of the retention programme, so wet-end changes should be evaluated alongside the chemistry already in use.

For packaging paper and packaging board, starch supports the strength the structure needs during converting, stacking and transport, and prepares the surface for printing. Requirements vary with grammage, ply structure and the end use of the board, so specification should start from the converting requirement rather than from the starch alone.

In laminating and corrugating adhesives, a pregelatinized fraction is commonly used as the carrier: it builds viscosity at ambient temperature and keeps the raw starch in suspension. Viscosity stability over the working life of the mix is usually the governing property, together with behaviour at machine speed.

• Make-up procedure — controlled addition under agitation to avoid lumping and inconsistent solids.
• Water quality and temperature — both change hydration and the viscosity you measure.
• Viscosity measurement — use one method consistently and state slurry concentration and temperature.
• Holding time and shear — viscosity can drift between make-up and application.
• System compatibility — assess with the full formulation, not the starch in isolation.
• Housekeeping — cold-solution systems still require normal microbiological control.

1. Define the process position first: wet-end, size press, coater, board or adhesive.
2. State the target solids and the viscosity window at the temperature of application.
3. Decide whether cold make-up is a requirement or a preference — this drives pregelatinized versus native selection.
4. Review the technical data sheet, including the stated test methods, before trialling.
5. Run laboratory make-up under plant conditions, then a controlled machine trial.
6. Lock the specification, batch coding and documentation requirements once the trial is validated.

We supply pregelatinized, native, modified and custom-developed grades and can develop a specification against a written performance brief. Speak to our technical team with your process position and target viscosity.