The adhesive is the layer nobody sees and the one that generates the most complaints: a perfect label that peels off is a label that failed. The choice depends on three variables, best answered in this order: which surface it is applied to, at what temperature it is applied and at what temperature it will live.
1. The surface
Adhesives bond by wetting the surface. High-energy surfaces (glass, metal, coated board, PET) wet well and accept a standard permanent adhesive. Low-energy surfaces (polyethylene, polypropylene, plastic pails and drums, dusty recycled corrugated) reject common adhesive and need high-tack or hot melt. Textured, rough or dusty surfaces reduce the real contact area and also call for high-tack.
Clean and dry the surface before applying: mold-release oil on new plastic containers, dust on corrugated board and condensation are the three most common causes of lifting, and no adhesive fully compensates for them.
2. Application temperature
This is the temperature of the surface at the moment the label is applied. A permanent acrylic needs to be applied above 5 °C; if the container comes out of the cold room, the adhesive does not flow and the label falls off within minutes. Freezer-grade adhesive is formulated to apply on surfaces down to −5 °C.
3. Service temperature
This is the range in which the label must stay bonded during its life: the refrigerator, the freezer, the oven, the motor, the sun. Each adhesive has a service range and it pays to choose the one that covers it with margin.
The six standard adhesives
| Adhesive | Service | What for |
|---|---|---|
| Permanent acrylic | −20 °C to 80 °C | General use on board, glass, plastic and metal, dry and humid. The default adhesive. |
| Permanent hot melt | −10 °C to 60 °C | High initial tack for high-speed application on corrugated and low-energy plastics. |
| High-tack | −20 °C to 90 °C | Rough, textured or dusty surfaces: pails, drums, recycled corrugated, polyethylene and polypropylene. |
| Removable | −10 °C to 60 °C | Removes cleanly from glass, plastic and coated paper. Price, promotion and temporary identification. |
| Freezer grade | −40 °C to 60 °C | Applies on surfaces down to −5 °C and holds at −40 °C. Frozen products and the cold chain. |
| High temperature | −40 °C to 150 °C | Reinforced acrylic for equipment identification, autoclave and heat processes. |
Typical cases
PET or glass bottle with a cold beverage
Permanent acrylic on BOPP. If the bottle is labeled straight after cold filling with condensation, apply before chilling or dry the bottle; if that is not possible, high-tack.
Polyethylene pail or drum with a chemical
High-tack on polyethylene, BOPP or laminated polyester. Standard permanent adhesive lifts within days.
Food labeled while frozen
Freezer grade on BOPP or polyethylene. It is the only adhesive that accepts application on an icy surface.
Corrugated box on a packing line
Hot melt for applicator speed and initial tack on board; high-tack if the corrugated is recycled and sheds dust.
Price or promotion label
Removable. It comes off clean from glass and plastic; on corrugated board it may tear fiber because the board is weaker than the adhesive.
Data plate on a motor or equipment
High temperature on polyester. It holds at 150 °C in continuous service and withstands heating and cooling cycles.
What the adhesive does not solve
A correct adhesive does not hold a rigid label on a tightly curved surface (the material lifts at its edges: use polyethylene or BOPP, not polyester), nor a label applied over dust, grease or moisture. It does not correct application without pressure either: the adhesive reaches its final strength 24 to 72 hours after being applied with even pressure.
When in doubt, request a sample of the material with the proposed adhesive and test it on your real container for a week under the conditions of use. It is free and avoids a whole batch with the wrong specification.
