What Is Water-Activated (Gummed) Tape?

What it is

Water-activated tape — also called gummed tape or gummed paper tape — is a paper tape, usually kraft, coated with a dry adhesive that becomes sticky only when it is moistened. The adhesive is normally based on starch; older products sometimes used animal glue.

It is used almost entirely for sealing corrugated cartons, from e-commerce boxes to heavy export shipments. Unlike a pressure-sensitive packing tape, which sits on the surface, the moist gum soaks into the paper fibres of the box. Once dry, tape and carton are effectively one piece.

Plain and reinforced types

Plain gummed tape A single ply of kraft paper with gum on one side. It suits light to medium cartons, envelopes and general paper sealing.

Reinforced gummed tape (RGT) Two plies of kraft paper laminated together with fibreglass yarns between them, often in a cross or diamond pattern. Today the laminating layer is usually a hot-melt adhesive; older reinforced tapes used asphalt. The yarns add tensile strength and tear resistance for heavy, large or export cartons.

In the United States, both types are covered by ASTM D5749, the standard specification for reinforced and plain gummed tape for sealing and securing.

How it is applied

1. A dispenser feeds the tape over a wetted brush or roller that applies a controlled amount of water to the gum.
2. The required length is measured and cut — on electric dispensers automatically.
3. The tape is laid across the carton seam and pressed down by hand.
4. The starch gum penetrates the board fibres and bonds as it dries.

Too little water gives a weak, patchy bond; too much dilutes the gum and slows drying. Dispenser settings and water temperature are adjusted to suit the tape and the board. A good seal can be checked simply: once dry, peeling the tape should tear fibres from the carton surface rather than lift cleanly.

Why choose water-activated tape

• Tamper evidence: the bond is into the fibres, so the tape cannot be lifted and re-stuck without tearing the carton surface.
• Strong bond to recycled board: it bonds well to dusty or recycled corrugated board where some pressure-sensitive tapes struggle.
• Often one strip is enough: a single strip across the seam usually replaces several passes of plastic tape.
• Paper-based: it can go through paper recycling with the carton, reducing plastic in packaging.
• Printable: kraft paper takes logos, handling instructions or security printing.
• Stable in storage: no tack until wetted, so rolls do not stick together.

Limitations

• A dispenser is needed for efficient use.
• It bonds well to paper and board, but poorly to plastic, metal or coated surfaces.
• Very cold or very wet conditions can affect bonding and drying.

Water-activated tape compared with alternatives

SyncSol offers pressure-sensitive paper alternatives such as Kraft Paper Tape and Paper Tape, along with Repulpable Tape for paper-mill splicing and Security Packing Tape for tamper-evident shipping.

Key takeaways

• Water-activated tape is kraft paper with a starch gum that bonds when moistened.
• It bonds into carton fibres, giving a strong, tamper-evident seal.
• Reinforced versions add fibreglass yarns for heavy cartons.
• It needs a dispenser and works only on paper-based surfaces.

Frequently asked questions