What is Aqueous Coating for Printing and Packaging?

1. When to coat?

In most instances, no matter what coating you are talking about, it will serve to protect and improve your final product. If you are going to mail your piece, it needs a print coating. If you think your print will be handled a lot, such as a business card or brochure, it is strongly recommended that you add a print coating for extra protection.

However, there are occasions when a print coating may hinder your print piece. Greeting cards do not require a coating, since it would be difficult to write on them with a coating on, which would defeat the object of greeting cards! However, if you want to apply a print coating to such products, you will need to ask your service provider to indicate which parts should not be covered by the coating, to prevent this issue.

Now that you know when it is good to use coatings, we will move on to the subject at hand.

2. What is aqueous (AQ) coating?

Unlike UV coating and varnish, AQ coating is water-based and is therefore the default coating for printing and packaging. It dries quickly when applied in the printing process, and can therefore be used to achieve different appearances.

In addition to this versatility, AQ coating is also renowned for being environmentally friendly thanks to its non-toxic water-based solvent, making it ideal for the following applications:

• Foods

• Household products

• and fast-moving consumer goods.

AQ coating does not leave fingerprints or other contaminants when touched, and it can be combined with various layers to increase surface durability. However, the type of product will be a major factor in determining the most suitable AQ coating for your packaging.

Remember that although this coating is water-based, it is not waterproof!

The chemicals in cosmetic products and perfumes can make it difficult to keep AQ coating on the inside or outside of packaging due to the possibility of leakage, so always consider the product and your needs when choosing a print coating.

To help you make a more informed decision, we have listed some of the main differences and characteristics between AQ, UV and varnish coatings.

-- Aqueous Coating

It is only available in flood form, which covers the entire printed material.

It uses a quick-drying, water-based solvent, making it the most cost-effective option.

It is also environmentally friendly due to the non-toxic, water-based solvent.

AQ is tough and offers high protection against scratches, fingerprints and scuffs. It is also less prone to yellowing than varnish and more adaptable than UV coating, which cracks when folded or creased.

It may be matte, satin or glossy.

-- UV coating

It is available as a flood or spot coating, enabling you to highlight certain areas of your printed work.

This process uses a solvent-based chemical that contains polyethylene (plastic) or calcium carbonate, which is less environmentally friendly than AQ coatings.

As the name implies, this option is dried and hardened with ultraviolet light, and the process takes place almost immediately.

Similar to AQ coatings, UV coatings can be matte or glossy; however, in general, UV coatings provide a glossier finish than AQ coatings. Some consider the finish to be too shiny, but this shine can actually make images stand out.

UV coatings are waterproof, chemical-resistant and do not turn yellow over time. They provide maximum protection compared to other alternatives.

-- Varnish

Varnish can be flooded or spot coated. However, they are heavier bodied and can only be applied to particular areas via a press plate. Detailed artwork should be sent to the service provider before the job begins.

Similar to an ink printing press, the surface of printed material is covered in a clear liquid, which can be either UV- or aqueous-based.

Varnish dries using UV light or heat, which is much slower than other possible options.

Varnish can also be applied in a matte, satin or gloss finish.

Varnishes provide good protection for your printed piece, but they may turn yellow over time. Unvarnished areas are more vulnerable to ageing.

If you find that the other alternatives are more suitable for your printing project, visit our UV coating or varnish articles to find out more. Otherwise, we will continue with our tour of aqueous coatings!

3. The advantages of aqueous coating

We have briefly touched on the advantages of AQ coating over other, more popular finishing techniques, but let's take a closer look at its four primary advantages to understand why so many companies opt for it.

It is non-toxic and environmentally friendly: the treated paper can easily be recycled, and it does not generate harmful by-products. Aqueous coating produces minimal solid waste, and the cleaning process does not require toxic cleaning agents.

Versatile: It is a multipurpose, hassle-free product that does not require further finishing and is compatible with other printing methods. It is also easy to write and print on the coating, offering more variety in finishes.

Cost-effective: This water-based coating is applied in line with the printing process, offering great cost savings.

Long-lasting and durable: The coating protects metallic inks by preventing them from coming into contact with air. Aqueous coatings are also less susceptible to yellowing and are therefore a better alternative to varnish.

4. Types of AQ coatings

As mentioned earlier, aqueous finishes are available in matte, satin or gloss. However, there are also other special types of coating that can be used to suit your printing requirements. Let's take a look.

Gloss: A gloss aqueous finish is best if you want a less flashy, more subdued finish. As mentioned previously, UV coating or film laminates are more suitable if you want a more glamorous look.

Dry-erase: A dry-erase AQ coating is an inexpensive alternative to laminate with a high-gloss finish.

Satin: Satin aqueous coating has a medium shine and high scuff resistance, giving it a look that falls between matte and gloss.

Matte: A matte aqueous finish has little shine or depth, but a high level of colour intensity.

Soft touch: A soft touch aqueous coating has a velvety texture and a soft look, as opposed to a glossy coating. Like a matte coating, it produces a slightly finished look with minimal or no shine.

5. The aqueous coating process

Now that we know the different types of coating in this popular printing method, how do we apply it?

Special machines are used to apply the aqueous coating, followed by printing ink on the sheets. The process involves paying extra attention to ensuring that the paper does not become wrapped, wrinkled or curled during application and after the coating has been applied, the sheet is placed in a heated air system to dry quickly.

6. The final coat for AQ

Despite the advantages of AQ coating, there is a high probability of chemical burning with aqueous and UV coatings compared to other finishes, such as varnish.

Aqueous coating is less solvent-resistant than UV coating and thermal lamination.

However, AQ coating remains the most popular print finish option thanks to its consistent, high-quality results.

Want to know more about what you can coat your packaging with?

Call our product experts for professional guidance on finishing and printing your product!