The adhesive is the whole point of water activated tape. It is a dry, plant-starch coating on kraft paper that does nothing until it is wet, then bonds hard into the fibres of a carton and dries rigid. Understanding how it works explains why the tape recycles with the box, why it needs a dispenser, why it has a shelf life, and why humidity is its enemy on the shelf.
For the product overview see the water activated tape guide; for the recyclability detail, 8 key insights on water activated tape.
Key points
- The adhesive is a starch or dextrin, made from corn, potato, wheat or tapioca. It is solvent-free and low-odour.
- Water hydrates the dry starch so its chains can hydrogen-bond to the cellulose fibres of both the tape and the carton. As it dries, that bond becomes rigid.
- Because it is starch, it re-dissolves in the paper repulping process and separates cleanly, so it does not contaminate recycling like acrylic or rubber adhesives do.
- It has a short open time (about 5 to 7 seconds of workable tack) with a little slip for adjustment.
- Starch is hygroscopic, so tape must be stored sealed and dry or it pre-activates and the roll blocks.
What the adhesive is made of
Modern water activated tape uses a plant-starch or dextrin adhesive. Dextrin is starch that has been partly broken down (usually by heat and acid) into shorter chains that dissolve and tack faster. The starch is sourced from corn, potato, wheat or tapioca, depending on the maker.
It is solvent-free: the only carrier is water, which leaves during drying, so there is very little odour and very low volatile emission compared with solvent-based adhesives.
Historically, gummed paper tape used animal glue (collagen from hides and bones). Animal glue tacks well, but it is expensive, hard to get in consistent quality, has an odour, and is unsuitable for anyone avoiding animal products. Starch and dextrin adhesives were developed to match its tack while removing those problems, and they are now the standard.
How activation works
- Dry state. The starch coating is a hard, glassy film. The starch chains are locked together and cannot move or bond to anything.
- Water is applied. A dispenser brush or a damp sponge wets the coating. Water molecules push between the starch chains and hydrate them, so the film softens and becomes tacky.
- Contact with the carton. Pressed onto corrugated board, the mobile starch chains form hydrogen bonds with the hydroxyl groups on the cellulose fibres, of both the kraft backing and the carton surface. The adhesive also flows slightly into the porous fibre structure.
- Drying. Water leaves. The starch chains re-lock, now anchored to the carton fibres. The bond becomes rigid, and pulling the tape off tears the carton surface rather than releasing cleanly.
This is why the tape has to go onto a porous, dry, paper surface: there is nothing for the starch to hydrogen-bond into on plastic, wax or a dusty carton.
Why it recycles cleanly
When a sealed carton goes into a repulper, it is agitated in warm water. The starch adhesive simply re-dissolves and disperses, the same way it activated. It stays in the water phase and is screened or washed out; it does not form the sticky residues, called “stickies”, that pressure-sensitive acrylic and rubber adhesives leave in the paper stream. Those stickies foul equipment and show up as defects in recycled paper, which is why plastic tape is meant to be removed before recycling.
So a starch adhesive is not just “not harmful” to recycling; it is actively compatible with it. That is the core of water activated tape’s environmental case, covered further in 8 key insights.
Tack, slip and open time
A good gummed-tape adhesive has to balance three things:
- Fast initial tack: it must grab within a second or two so the packer is not holding the strip in place.
- Some slip: a brief window where the strip can be nudged straight before it sets.
- Open time: the tack must not disappear if the packer is a few seconds slow. Practical open time is around 5 to 7 seconds.
Too little water and the film never fully hydrates, so tack is weak and the edges lift. Too much water and the starch over-dilutes, so the strip is slippery, curls, and takes a long time to hold. The how to use guide covers getting the water level right.
Same adhesive, different carrier
The starch adhesive is essentially the same on non-reinforced and reinforced tape. What changes is the carrier: non-reinforced is a single kraft ply; reinforced laminates fibreglass yarns between two kraft plies. The bond into the carton is the adhesive’s job; resisting the tape splitting along its length is the carrier’s job.
Storage and shelf life
Starch is hygroscopic, meaning it pulls moisture from the air. That is a problem on the shelf:
- Store sealed. Keep rolls in their humidity-proof film or box until use. An opened roll left out in a humid pack area can slowly pre-activate.
- Conditions. Around 21°C and 50% relative humidity, out of direct sun, is ideal. Avoid a hot roof space or a damp store.
- Shelf life. Sealed and stored well, roughly one to two years. Heat and humidity shorten it.
- Signs a roll has gone off: the layers stick to each other (blocking), the surface feels tacky when dry, or the tape curls badly off the roll. A blocked roll will not dispense cleanly and should be replaced.
In a humid Australian summer, the single most useful habit is to only open a roll when it goes on the dispenser, and to keep the pack area dry.
A note on food contact
The starch adhesive itself is benign, and the same starch chemistry is used in food-grade adhesives elsewhere. That does not make a roll of packaging tape a food-contact material: it is manufactured as industrial packaging, not to a food-contact standard. Use it to seal the outer carton, not as anything that touches food. If you need a food-contact application, ask for a product certified for it.
How Carewell Group fits: the right adhesive for the job
Carewell Group is an Australian packaging manufacturer and supplier. We design custom packaging around your product, add your branding and print, and supply the whole dispatch line from one place, so the tape, the carton and the dispenser are matched.
- Water activated tape with a plant-starch adhesive, reinforced or non-reinforced, plain or custom-printed in water-based inks so the whole carton still repulps cleanly.
- Biodegradable and recycled-content options, such as the biodegradable recycled reinforced water activated tape.
- Dispensers that wet the adhesive evenly for consistent tack: see the dispenser guide.
- Custom design and engineering. If your product needs a specific carton, insert or seal, we build it to fit rather than making you adapt to stock sizes. From engineering to finished, ready-to-use packaging, your business gets a solution, not another task.
- Browse the water activated tape range.
Carewell operates from NSW with warehousing in Smithfield, Matraville and Padstow, works with clients across grocery and retail, e-commerce, food and beverage, and industrial and manufacturing, and is certified to ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018, and an APCO member.
Questions about the adhesive for your application? Request a quote and samples or call +61 (02) 8760 1491.
Frequently asked questions
What is the adhesive on water activated tape made of?
A plant-starch or dextrin adhesive, from corn, potato, wheat or tapioca. It is solvent-free and low-odour. Older gummed tape used animal glue, which starch has largely replaced.
How does water activate the adhesive?
Water hydrates the dry starch film so its chains can move and form hydrogen bonds with the cellulose fibres of the carton and the tape. As it dries, the bond sets rigid.
Why does starch adhesive recycle better than plastic tape adhesive?
It re-dissolves in the repulping water and washes out, instead of forming the sticky residues (“stickies”) that acrylic and rubber pressure-sensitive adhesives leave in the paper stream.
How should I store water activated tape?
Sealed, around 21°C and 50% relative humidity, out of direct sun. Starch draws moisture from the air, so an open roll in a humid area can pre-activate and block.
How long does water activated tape last?
Roughly one to two years sealed and stored well. Heat and humidity shorten it. Replace a roll if the layers stick together or it curls badly off the roll.
Sources
- Jota Machinery, how to make a starch-based adhesive for gummed tape (starch/dextrin sources, tack, open time): jotamachinery.com
- US patent literature on gummed-tape adhesives (starch/dextrin vs animal glue, tack and slip requirements)
- Adhesive shelf-life and storage guidance (temperature, humidity, sealed packaging)
- ScienceDirect overview, starch adhesive properties and cellulose bonding: sciencedirect.com
Written by Alif Vasaya, digital and content strategy, Carewell Group. Carewell Group is an Australian packaging, food packaging, tape, industrial safety and 3PL supplier. Last updated 10 September 2026.