Technology

What actually happens in the water

A water-soluble label is not a trick coating. It is a polymer that has been engineered to give up its own structure at a temperature you choose. Here is the mechanism, the variables, and how we prove it.

The dissolution mechanism

Polyvinyl alcohol dissolves in four overlapping stages. The formulation controls how fast each one happens — which is how a single chemistry can be tuned anywhere between 5 °C and 90 °C.

Wetting

Water reaches the surface and penetrates the coating. Surface energy and any topcoat decide how quickly this starts.

Hydration

Water molecules hydrogen-bond to the hydroxyl groups along the PVA chain, forcing the polymer network apart from the inside.

Disentanglement

Swollen chains slide free of each other. The sheet loses cohesion here — this is the moment a wash-off label releases in one piece.

Dispersion

Individual chains leave into solution. Nothing settles, nothing films, and the polymer biodegrades downstream.

Technology

Choosing the dissolution window

The single most important decision. Set it too low and the label fails in condensation; too high and your wash line will not release it. Drag to see how each grade behaves.

Cold water5 – 25 °C · WF-200 · WA-400

Warm water30 – 55 °C · WP-100 · WZ-600 · WT-700

Hot / caustic60 – 90 °C · WB-300 · WK-500

Water temperature

22 °C Stable — label stays put

Wash-off, fully soluble, or conventional?

Three different answers to the same question. They are not interchangeable — the right one depends on whether your line can screen solids and whether the adhesive may enter the water.

Wash-off, fully soluble, or conventional?
	Conventional PSA	Wash-off	Fully soluble
Removal method	Soak, scrape or blast	Alkali bath releases the label whole	Everything goes into solution
Adhesive fate	Stays on the container	Stays with the label	Dissolves with the face stock
Line residue	Fibre, adhesive, ink	Whole labels, screened out	None
Caustic consumption	High	Reduced	Low or none
Best for	One-way packaging	Returnable glass at scale	Crates, kegs, vessels, kitchens

How we prove it

A dissolution claim is worthless without the conditions attached. Every batch is run against the parameters you supply, and the certificate travels with the goods.

Bath simulation

Your temperature, your caustic concentration, your agitation. Timed to full release, recorded on video for the first article.

Condensation survival

24 hours in ice water at 1 °C with the label under load, to confirm it will not lift in your cold room.

Ink and residue check

Bath filtered and the glass inspected under raking light for adhesive ghosting or ink bleed.

Batch certificate

Release time, temperature, concentration and operator, signed and filed against the production lot.

Straight answers

Will it come off in the rain or in a chiller?

No. Cold-tack and wash-off grades are tested for 24 hours in ice water under load. Failure in condensation is almost always a specification error — the dissolution window was set too low for the environment.

Can I print it on my existing press?

In most cases yes. Water-soluble paper runs on standard flexo and offset presses with UV or water-based inks; the main change is humidity control in the pressroom and slightly lower web tension.

What happens to the polymer after it dissolves?

PVA is biodegraded by activated sludge in conventional wastewater treatment, ultimately to carbon dioxide and water. We supply BOD and COD data so your treatment plant can be checked.

Is it food safe?

The foodservice and film grades comply with FDA 21 CFR and EU 1935/2004 for their stated conditions of use. Migration statements are issued per construction, not per range.

How is it different from ordinary wash-off labels?

A wash-off label releases whole and has to be screened out of the bath; the adhesive leaves with it. A fully soluble construction puts both the face stock and the adhesive into solution, so there is nothing to screen at all.

What is the shelf life of the material?

Twelve months in original packaging at 20 °C and 50 % relative humidity. Water-soluble stock is hygroscopic, so it must stay sealed until it goes on press.

Request a sample

Send us the hardest label on your line

Tell us the container, the wash chemistry and the temperature. We will tell you honestly whether a water-soluble label is the right answer — and prove it with a sample.

Request a sample Talk to an engineer

Free samples · 7-day turnaround · NDA on request