Paper packaging has made significant progress with dry products.

Liquids are much harder.

That is why a new 5ml hand-wash sachet from Bower Collective and UK biomaterials company Kelpi deserves attention.

The pack uses paper coated with Kelpi’s seaweed-derived barrier material, removing the conventional fossil-fuel plastic lining normally used to stop liquid from penetrating the paper.

Bower is initially using the sachets for samples of three hand-wash fragrances. Guardpack manufactured and filled the packs on its existing sachet equipment.

But the most important part of this development may not be the seaweed.

It is that the material reportedly ran on an existing commercial filling line without equipment changes.

Barrier coatings are the real challenge in paper flexibles

Paper alone cannot reliably hold a liquid hand wash.

It needs a barrier against moisture and usually a heat-sealable surface so the package can be closed at production speed.

Conventional sachets achieve this using multilayer structures combining polymers and other materials.

Those laminates perform well, but separating the layers after use can make recycling difficult.

Kelpi takes a different approach.

The company extracts carbohydrates from seaweed and combines them with plant-derived oils to produce an ultra-thin coating for paper and fibre substrates. Kelpi reports a coating thickness of around 0.01 mm and water-vapour transmission performance below 2 g/m²/day in some applications. Performance varies with the final packaging structure.

The engineering objective is therefore not simply:

replace plastic with seaweed.

It is to give paper enough barrier and sealing functionality without turning the finished structure into another difficult-to-recycle laminate.

Running on existing machinery could determine whether it scales

Kelpi and Guardpack began production-line trials earlier in 2026.

Guardpack reported that the material demonstrated reliable sealing, machinability and printability during those trials. The new Bower sachet moves that work into an actual consumer application.

That transition matters.

Packaging technologies frequently fail to scale because they require:

slower line speeds,

new sealing systems,

special handling,

or expensive equipment modifications.

Every required machine change increases the cost of adoption.

Kelpi says the Bower sachets were produced on Guardpack’s standard lines without equipment changes, which suggests the coating may have a lower implementation barrier for existing sachet converters.

It is still a small-volume sampling application, however.

Five-millilitre hand-wash sachets do not yet prove the material can economically replace conventional flexible packaging across larger packs, higher production volumes or more demanding formulations.

That will require additional commercial evidence.

Recyclability is more important than being bio-based

Kelpi describes the finished paper structure as compatible with household paper recycling.

The company says its coated materials are certified for standard paper recycling streams and has referenced testing against the CEPI recyclability methodology.

That distinction matters.

A coating being derived from seaweed does not automatically make the package recyclable.

The paper industry ultimately needs to know what happens when coated fibre enters a pulper:

Can the fibre be recovered?

Does the coating interfere with screening?

Does it create problematic residues?

Does it affect the quality of the recovered fibre?

Those questions are more important to paper mills than whether the coating feedstock originally came from petroleum or biomass.

“Biodegradable” should remain a secondary claim

Kelpi also says its coating is designed to biodegrade rather than persist if it escapes into the environment.

That could provide an additional end-of-life advantage for very small packaging formats, which are particularly vulnerable to leakage.

But biodegradability should not become a substitute for collection.

The preferred route for a fibre-based sachet is still:

use → collection → paper recycling.

Environmental degradation is a fallback for accidental leakage, not an alternative waste-management system.

And the performance of any biodegradability claim depends on the specific test conditions, timescale and complete finished-package construction.

Kelpi is moving beyond a laboratory material

The Bower launch also fits into a broader commercialization push.

Earlier this year, Kelpi partnered with Amcor to evaluate the coating for Amcor’s fibre-based packaging portfolio, including applications requiring moisture and gas barriers.

In August, Kelpi also announced that its coating had cleared the U.S. FDA food-contact notification process for specified paper and board applications, removing another regulatory barrier to expansion into food packaging.

Together, those developments suggest the company has moved beyond proving that the chemistry works.

The harder challenge now is proving that it can be:

manufactured at scale,

coated consistently,

converted at industrial speed,

filled reliably,

and recycled through real paper systems

at a cost brands are willing to pay.

The 5ml sachet is small, but the test is important

Bower’s launch is deliberately limited.

The sachets are samples rather than a wholesale replacement of the company’s packaging portfolio. Bower itself describes the launch as limited edition.

That makes it a useful commercialization test rather than proof that plastic sachets have already been solved.

But the application tackles one of the harder challenges for paper packaging:

putting a liquid inside paper while keeping the structure simple enough for the paper recycling stream.

If Kelpi can demonstrate the same combination of barrier performance, machine compatibility and recyclability at substantially larger scale, the opportunity goes well beyond hand-wash samples.

It could open more applications in:

personal care,

home care,

food,

and other small-format flexible packaging.

The seaweed makes the technology distinctive.

But the commercial breakthrough will depend on something less visually exciting:

whether converters can run it quickly, brands can afford it, and paper mills can actually recycle it.

Last Updated on 22/09/2026 by Jota Machinery