How barrier coatings are expanding the potential of paper packaging

Water-based, bio-based and speciality barrier coatings are helping paper packaging move into applications once dominated by plastic, but performance, machinability and recyclability must be engineered together.

Paperisation is moving beyond straightforward plastic substitution. As packaging producers use paper and fibre in more demanding applications, the focus is shifting to the coatings that allow these materials to deliver the required performance.

Paper-based packaging increasingly needs to withstand moisture, grease, oxygen, heat and the stresses of converting and sealing. These functions have traditionally been provided by plastic films, polyethylene layers and other multi-material structures.

Barrier coatings offer a way to build some of that functionality into paper and board while keeping fibre at the centre of the pack.

Water-based dispersions, bio-based polymers and other speciality coatings are being developed to provide specific barrier and sealing properties at low coating weights. The objective is not simply to remove plastic, but to create fibre-based packaging that works on commercial production lines and is compatible with the recycling process for which it is designed.

The next phase of paperisation will therefore depend on whether a complete packaging structure can balance performance, manufacturability, cost and end-of-life requirements.

Why paper packaging needs barrier coatings

Paper is strong and lightweight, but its porous fibre structure provides limited protection against liquids, moisture, oils and gases. Uncoated paper can also lack the heat-sealing properties required for many high-speed packaging applications.

Barrier coatings are designed to overcome these limitations. Depending on their formulation, they can provide resistance to liquid water, water vapour, oxygen, oil and grease. Some also provide heat-sealing functionality, opening paper-based formats such as bags and sachets to applications that have traditionally depended on plastic structures.

The technology encompasses a range of chemistries and application methods. Dispersion coatings, for example, can be applied using established coating technologies and engineered to provide several functions in a thin layer.

The commercial attraction is straightforward. If a coating can deliver the required performance without adding excessive material or requiring major changes to converting equipment, packaging manufacturers have a more practical route to introducing fibre-based structures.

The challenge is to achieve the right level of protection rather than simply the highest possible barrier. Over-engineering a pack can add cost, material and complexity, potentially weakening the commercial and environmental case for the change.

Can water-based coatings replace polyethylene layers?

Water-based barrier coatings are becoming an important technology for recyclable paper packaging. Suppliers are developing systems that combine functions including water and grease resistance, heat sealing and resistance to damage during folding and converting.

Henkel expanded its portfolio of water-based barrier and heat-seal coatings for paper applications in 2026. The company says the systems are designed for food and non-food packaging and can be integrated into standard coating and packaging processes. It also describes the coatings as repulpable and compatible with recycling.

BASF has developed water-based polymer systems for paper and board packaging, including its Joncryl HPB range. The company says these coatings provide properties such as water and grease resistance and heat sealability, with performance designed to be comparable with conventional polyethylene extrusion coatings in some applications.

These developments show why paperisation is becoming a systems-engineering exercise. A successful structure may require the substrate, barrier coating and sealing system to work together without compromising the intended recycling route.

There is also an important distinction between water-based, bio-based and plastic-free packaging.

Water-based describes the medium or process used to formulate or apply a coating. It does not necessarily mean that the coating contains no synthetic polymer. A bio-based coating refers to materials derived partly or wholly from renewable biological sources. Neither term, on its own, guarantees that a finished package is plastic-free or recyclable.

For packaging manufacturers, the more useful question is therefore what the complete structure contains, how it performs during manufacture and use, and how it behaves at end of life.

Bio-based barrier coatings move towards commercial use

Alongside conventional dispersion chemistry, research is advancing into bio-based and naturally derived barrier materials.

Cellulose, starch, chitosan, lignin, proteins and other bio-derived materials are being investigated as coating components because they can form protective layers while potentially reducing reliance on fossil-derived raw materials.

Recent research is also examining combinations of biopolymers, nanomaterials and bionanocomposites to improve resistance to water, water vapour, oils and gases.

The potential is particularly relevant to paper and moulded-fibre packaging. Research into starch-based systems, for example, is examining ways to improve resistance to water vapour, oxygen and oils while addressing the thermal sensitivity and manufacturing challenges that can limit wider adoption.

But bio-based does not mean technically straightforward.

Moisture resistance remains a challenge for many natural materials. Performance can also change with temperature and humidity, while cost and industrial-scale production present further hurdles.

A 2026 review of bio-based barrier coatings identifies moisture, temperature and gas tolerance, together with cost, among the main obstacles to wider application.

For converters, promising laboratory performance is only the starting point. A coating must also deliver consistent application, drying, converting and barrier performance at commercial speeds.

Research is therefore increasingly focused on combining materials and barrier mechanisms rather than finding a single natural material capable of performing every function.

The objective is to achieve the required functionality at low coating weights without creating new problems during converting or recycling.

Moulded fibre brings new barrier challenges

The paperisation trend extends beyond flexible paper and board. Moulded fibre is increasingly being developed for trays, food containers and other rigid formats where plastics have traditionally provided structural strength and resistance to liquids and grease.

The underlying problem is similar. Fibre is naturally porous, so the surface or internal structure of a moulded-fibre product needs to be engineered to prevent liquids and oils from penetrating.

A coating is one solution. Another is to modify the fibre network itself or incorporate functional materials into the structure.

Barrier development for moulded fibre increasingly includes water-based and bio-based systems intended to provide alternatives to PFAS-containing treatments. Process innovation is also expanding the potential applications for moulded pulp.

Smithers identifies coatings and process technologies as important areas of innovation, while noting that applying water-based coatings to deep three-dimensional moulded-fibre objects remains technically challenging.

This matters because a fibre tray has to do much more than resemble a plastic replacement. It must survive filling, stacking, transport, storage and consumer use without losing its structural or barrier properties.

For moulded fibre in particular, the relationship between material design, forming technology and coating performance is becoming a key area of innovation.

Barrier performance must survive converting and sealing

Strong laboratory barrier results do not automatically translate into a commercially viable package.

Coating weight, drying conditions, substrate characteristics, surface properties, folding, creasing, sealing temperatures and production speeds can all affect the finished structure. The interaction between the coating and the underlying paper or board is equally important.

Creasing is a particular challenge. A coating that performs well on a flat sheet can develop weaknesses when the material is folded or formed into its final shape. Damage at a crease can create a pathway through which moisture, grease or gases can penetrate.

Sealing presents another hurdle. Plastic films have traditionally offered predictable heat-sealing performance. Paper-based structures need to achieve sufficient seal strength and process stability at commercially viable line speeds while maintaining their intended recycling characteristics.

Cold sealing provides another option for suitable applications, particularly where the product should not be exposed to elevated sealing temperatures.

In 2026, Henkel introduced a cold-seal solution specifically designed for barrier-coated paper, targeting applications including snacks, ice cream and chocolate. The company says the system has been tested for compatibility with mechanical paper recycling.

The development illustrates how sealing technology is evolving alongside barrier coatings as suppliers seek to make paper structures viable for a wider range of packaging applications.

For packaging producers, the target is therefore not maximum barrier performance at any cost. It is the level of performance required for the application, delivered with the minimum necessary coating weight, material complexity and disruption to production.

Recyclability starts with coating design

A paper package is not automatically recyclable simply because paper or fibre represents most of its weight.

Coatings, films, adhesives and other non-fibre components can affect repulping and fibre recovery. The suitability of a coating therefore needs to be considered alongside the intended recycling process and the complete packaging structure.

This makes recyclability a design requirement rather than a characteristic to assess after the pack has been developed.

The regulatory environment is reinforcing that approach. The EU Packaging and Packaging Waste Regulation (PPWR) entered into force on 11 February 2025 and began applying generally across the EU on 12 August 2026.

 It covers packaging and packaging waste across the full life cycle and sets requirements for manufacturing, composition and the reusable or recoverable nature of packaging.

The PPWR also introduced restrictions on PFAS in food-contact packaging from 12 August 2026. Food-contact packaging containing PFAS above specified limits can no longer be placed on the EU market. PFAS have been used in some food packaging applications to provide resistance to water and grease, increasing the importance of alternative barrier technologies.

For coating developers, this creates a dual challenge: provide the necessary functional performance while avoiding substances and structures that create problems at end of life or under changing regulatory requirements.

It also means that claims such as “recyclable”, “plastic-free” and “bio-based” need to be treated separately. A packaging structure should be assessed as a whole rather than judged by the chemistry of a single coating.

Paperisation shifts from substitution to optimisation

The market for barrier coatings is already substantial. Smithers estimates that barrier coatings accounted for 4.4 million tonnes of global demand worth $9.97bn in 2025, making them the largest segment of the wider packaging coatings market. Water-based coatings are the second-largest coating technology by volume and are forecast to be among the fastest-growing technologies through 2031.

Development is taking place across several fronts. Suppliers are combining grease, water-vapour and oxygen barriers with heat or cold sealing, while research is advancing bio-based polymers, cellulose-derived materials and multi-component systems. Moulded-fibre producers are also seeking ways to add barrier performance without sacrificing the advantages of fibre.

For packaging manufacturers, the commercial question is increasingly one of optimisation.

Barrier performance must be balanced against coating weight, machinability, sealing, food-contact compliance, cost and end-of-life behaviour. Improving one characteristic at the expense of another does not necessarily produce a better package.

Paper provides the fibre base. The coating can supply functions that fibre cannot deliver alone. Converting determines whether those properties survive production. Recycling determines whether the resulting structure can fulfil its intended circularity objectives.

The next generation of paper packaging is therefore unlikely to be defined simply by the absence of plastic. Its success will depend on engineering fibre-based structures that provide the performance, production efficiency and end-of-life characteristics required by modern packaging applications.