Waterproof Cardboard

Liquiguard is a water and oil resistant coating that has been developed for use across various industries.

Typical applications are for wet and oily products such as meat, fish, fruit, vegetables, and flowers, but it is also used successfully in moving automotive and industrial components that are greasy.

Using Liquiguard to manufacture waterproof cardboard packaging with resistance to moisture, oil and grease can also help to minimise or completely eliminate to need for secondary packaging such as bags and films. This not only reduces ongoing costs but can also help to shorten packing times and improve productivity.

Using waterproof cardboard provides improved performance over standard corrugated cartons, offering a higher level of protection to the packaged contents (helping to minimise the costs of damage during transit or storage).

Liquiguard coated packaging also boasts enhanced durability and lifespan, allowing it to be re-used multiple times.

Unlike many other forms of water-resistant corrugated packaging – such as plastic-coated cardboard – Liquiguard is also completely biodegradable and recyclable. This means that disposal costs for the end user are also vastly reduced.

And finally, Liquiguard is FSA approved for direct contact with food.

Liquiguard coating allows your sheet plant to offer high quality, moisture, and oil resistant corrugated packaging to your customers. Similarly, all of the coatings available at GWP Coatings provide your business with the ability to offer your customers a wider range of products and options.

Not only can this be the difference in winning new business, but it can also allow for upselling to existing customers. Ultimately, it can increase your sales and have a direct, positive impact on your bottom line.

Runs for Liquiguard waterproof cardboard sheets start from as low as 200sq. metres, with lead times between 24 and 48 hours. This allows you to be more responsive to urgent requirements, as well as the flexibility to offer your customers lower volumes too (ultimately boosting sales figures).

Liquiguard waterproof cardboard coating can be safely handled without protective clothing (PPE), and is easily converted on the vast majority of standard equipment (more so than traditional waxed cardboard sheets).

It can be overprinted, glued and due to being completely inert, any waste materials can simply be recycled in the same manner as normal corrugated (unlike film coated alternatives).

You can also choose to either supply the board to be coated or source both material and coating directly from GWP – the latter ensuring compatibility and minimising transit costs.

Finally – and crucially – Liquiguard and all GWP’s coated material can be supplied as part of a confidential, trade agreement.

Liquiguard waterproof cardboard coating is a blended waterborne acrylic lattice, which creates a totally non-hazardous inert translucent film when coated and dried onto paper or corrugated cardboard, whilst containing only water as the carrier system with no halogenated compounds or hydrocarbon co-solvents.

The materials used to manufacture Liquiguard coating are acrylic emulsions which are fully biodegradable and recyclable on normal paper materials.

Liquiguard is FDA approved for direct contact with food, but care should be taken when it is applied to test liners as the make-up of the test liner cannot be guaranteed.

It is readily accepted at paper mills who prefer it over polylined or wax impregnated cardboard, both of which are not environmentally friendly.

The minimum run is normally 200 sq. metres onto any fluted board grade, with a maximum board size of 1500 x 3000 mm.

Liquiguard waterproof cardboard coating requires special PVA adhesive for cold gluing or a hot melt adhesive which can be advised on.

Liquiguard is excellent for storing frozen foods and will not separate from the liner and can also be used for ‘cook in the box’ products.

Best results are obtained on pure kraft or white top kraft liners. Test liners can be used; however, these are not certificated.

Liquiguard can be applied to either one or both sides of corrugated board and gives a clear finish but tends to darken the underlying paper.

It can normally be overprinted with water based Flexographic inks or, alternatively, can be used over the top of Spectrumcoat coloured or other pre-printed board to give an enhanced visual appearance.

For performance details of the Liquiguard waterproof cardboard coating, please continue reading below.

Alternatively, for full technical specifications, benefits, applications, and conversion information, please download the datasheet here.

The endurance of water and oil resistant board is normally measured by the Cobb and 3M tests.

This determines water absorption. There are three exposure times used: 1 minute, 3 minutes and 30 minutes.

The test involves a known volume of water (100 ml) being poured onto a specific area of the board’s surface (100 cm2). The board is weighed before and after the exposure and the difference between the two can then be expressed as the weight per unit area of water absorbed in that given time, so the lower the Cobb value the better the result.

Typical test results obtained on Liquiguard material are below:

Cobb: 3 minutes = 2.0

Cobb: 30 minutes = 10.0

This involves putting five separate drops of various solvents onto the boards surface and inspecting it after 15 seconds to see if any pinholes appear (visible as dark specks).

The solutions range from a thick vegetable oil to thinner substances like white spirit. Each solution is numbered up to a maximum of 12 and the higher the number achieved the more resilient the surface.

Typical test results obtained on Liquiguard material are below:

3M Kit Test: = >12

Please see below for a collection of the most commonly asked questions regarding Liquiguard.