Returnable glass bottles — used across beer, soft drinks, dairy, and edible oil — go through repeated fill-label-sell-collect-wash cycles. The label must adhere reliably on shelf but release completely and cleanly in the bottle washer, leaving no adhesive residue that would contaminate the next batch or foul washing equipment.
This is a demanding and highly specific application. Standard removable PSA grades will not work — they are not designed for hot caustic conditions and will leave residue. You need a dedicated wash-off PSA formulation. If you are qualifying an adhesive for beer or beverage bottling in India, see our caustic wash-off supplier guide.
How Wash-Off PSA Works
Wash-off PSA emulsions are formulated with alkali-soluble or alkali-dispersible polymer systems. In ambient conditions, the adhesive behaves like a standard PSA — good tack and peel for reliable label application and shelf life. When exposed to hot NaOH solution (typically 1.5–3% NaOH at 60–80°C for 10–20 minutes), the polymer dissolves or disperses, releasing the label and leaving the glass clean.
| Parameter | Typical Range |
|---|---|
| NaOH concentration | 1.5 – 3% |
| Wash temperature | 60 – 80°C |
| Label contact time | 10 – 20 minutes |
| Pass criteria | Zero residue on glass |
What to Test Before Qualifying
- Complete label removal from glass surface
- No adhesive residue visible under good lighting
- No foam build-up in wash tank
- No filter clogging from adhesive particles
- Repeat after 7-day aged dwell at 40°C/80% RH
Paper vs Film Labels on Returnable Bottles
Paper Labels
The standard choice. Paper absorbs wash water, swells, and detaches. Pulp is easily filtered from wash water. Simpler process, lower risk.
BOPP Film Labels
Growing in India for better print quality. Film does not disperse — must physically detach. Requires label traps and filtration in your washer.
Focus Polymers WO-1918
WO-1918 is our dedicated wash-off grade, engineered for Indian and export returnable glass bottle applications. It passes standard caustic wash at 65°C / 2% NaOH with complete label release and zero residue on glass.
Request a WO-1918 Sample
Minimum trial order 200kg. Full TDS, SDS, and wash-off test data included.