What is Aqueous Coating Printing in Packaging?

Browsing or buying products, but noticing some of the boxes in which they are packed look dull or glossy, but WHY?

All because of the coating, and most probably its “aqueous coating”, which is applied during the printing process of many supplies. But curious, what exactly is aqueous coating in printing, and why use it?

Quick Answer

In the case of the printing and packaging industry, where it is used the most, aqueous coating is a clear, water-based varnish, mostly applied to things like boxes, brochures, or recycled paper, for two main purposes:

• Enhance Appearance
• Provide Protection

This is a quick look at what aqueous coating is, the full form of AQ coating, why it should be used, and what exactly the aqueous layer does.

But, to better understand and address all your concerns, we are going to talk all about aqueous solutions, their properties, types, and the multiple ways to apply them.

So, we recommend reading the full guide to find out whether this coating is a perfect match for your custom packaging boxes and avoid future misconceptions. Let’s start!

What Is Aqueous Coating All About?

Aqueous or AQ coating is a water-based varnish made from water and non-toxic polymers. These polymers are totally different from the traditional polymers like Polyethylene (PE). They are further dissolved into water and form a solution.

This adds another point to their beauty, as it is an environmentally friendly option that clears all your concerns regarding does aqueous coating contains plastic? 

When Should Aqueous Overlay Be Applied to Supplies?

Not only the customers but also many packaging manufacturers and printers are stuck here: When should an aqueous overlay be applied to packaging supplies?

This is also because accurate and vibrant printing results are essential to ensuring client demands, leaving you to consider whether you can write on aqueous coating before or after printing.

Well, it depends! There are no restrictions; you should apply AQ coating before printing or after, as it works well and serves you from their respective prospects in both processes:

• In pre-press (before printing)
• In post-press (after printing)

In pre-press (before printing)

In this process, the coating is applied first to the substrate before the printing process starts. The “substrate” is the base material you print on. And then dried and printed later.

Benefits: This gives the substrate a smooth and uniform appearance, which promises better ink adhesion and consistent printing.

In post-press (after printing)

As the name suggests, this method includes applying the coating when achieving the customer’s dream design, and then layering it with aqueous coating.

Benefits: Applying after the printing, it acts like a protective layer that not only makes the visuals sharper. But also improves their longevity by protecting them from fingerprinting and scratches during transit.

What Aqueous is in Pre & Post-Press: With Example

Let’s understand what aqueous is with an example in Pre & Post-Press:

For instance, if you want to print a brand logo on kraft packaging boxes, then here is the complete post-press procedure:

• The Kraft box is the substrate.
• The ink is printed onto the substrate.
• Lastly, aqueous water-based coating is applied.

Or, for pre-press, only just the last two steps are changed; coating is applied first, and then printed.

So, here is the printing difference, and the clear answer to your question: you can write on aqueous coating, which is YES, you can!

Note: You can apply aqueous coating printing before and after, but as a packaging supplier for decades, PremiumCustomBoxes suggest applying coating after printing, not before! Because it acts as a protective layer. However, in special cases or on client demand, you can do so after printing.

Unmatched Advantages of Applying Aqueous Coating In Printing

Understanding the coating itself and its application time, making it clear what would be the perfect option for you.

Now, it’s also crucial to know what you can expect from applying aqueous coating in printing (without before or after consideration). So, here are 5 unmatched benefits that this coating provides, and you can experience:

Protection & Durability

It acts like a wall against factors like moisture or heat, which impact the printing quality. This results in colour fading, which you see on some boxes.

Likewise, it also helps to upgrade the printing life expectancy, making it more resistant to scratches and fingerprints, and making the results as vibrant as they are supposed to be.

Appearance & Finish

Brightens the printing results, aqueous coating for printing, making the colors or patterns more vibrant or bold, ensuring the results appear more appealing while catching every eye, and turning heads.

Here, the term customization comes, which allows you to add any of the desired finishes according to the customer’s demands, as AQ coating is further divided into various types.

Different Types Of Aqueous (AQ) Coating For Packaging Supplies

Aqueous printing coating is for two main finishes in terms of appearance, such as:

• Glossiest
• Dullest

Moving from glossy to dull finish, we see 5 different types of AQ or water-based coating, which include:

Environmentally Friendly

Aqueous is mainly composed of water, which is why it is also known as a water-based coating. As we discussed earlier, it contains a small amount of polymers and doesn’t contain volatile organic compounds (VOCs).

VOCs are organic (carbon-based) chemicals that exist as gases or vapors and can cause Irritation and Neurological Effects, making AQ coating an ideal option for environmentally friendly packaging.

Non-Yellowing Nature

It does not contain any oil or solvent, and has the unbeatable property of drying out quickly; aqueous water coating doesn’t become yellow over time, like varnish, which may turn yellow slowly but surely, when exposed to moisture, heat, or sunlight, and that is the main difference between aqueous and varnish.

Several Methods To Coat Aqueous Finish On Supplies

The material supplies can be coated with an aqueous finish using special machines and under the consideration of packaging engineers for quality control, avoiding the paper wrap, wrinkles, or curls during aqueous coating in printing.

The process remains the same, but can be applied through several techniques or methods, which include:

• Roller Coating: This method uses a roller to constantly apply the coating to the surface.
• Gravure Coating: This technique uses an engraved cylinder to transfer the coating to the substrate (the base material).
• Flexographic Coating: Flexo or flexographic coating is a cost-effective method that uses flexible relief plates to transfer ink to a substrate.

Various Limitations of Aqueous Coating Printing

With a diverse range of uses and benefits, water-based or AQ coating looks fantastic and makes you feel like, “Put everything else aside; just choose Aqueous!“, right?

But wait, with a variety of benefits, it has some limitations, as it is quite important to highlight them to avoid misconceptions and financial loss if you use it for your packaging to expect the luxury box, but you will find out that it is nothing. Here are some of the limitations, which include:

Water-Resistance

Water-based and waterproof are two different things; as it is a water-based coating, some people take it as a coating that is resistant to water. Nope!

Water-based means having water as a primary ingredient, yeah! That’s what AQ coating has. Conversely, waterproof refers to something that is resistant to moisture. See how different these things are, making it clear that AQ coating is not waterproof.

And, this is the main limitation that makes it unsuitable for cosmetic, perfume, beverage packaging, or anything that has a high chance of breakage or leakage during transit.

Temperature Sensitivity

One of the other limitations or lack of aqueous film is temperature sensitivity. This means that at high heat, where the temperature crosses 232°C or 450°F, its viscosity decreases. And, the shocking part? It serves you in two possible ways:

Ease of Application: This makes the coating easy to coat or apply to the substrate, but again, results in drooping and inconsistent coats in several areas.

Application Issues: When exposed to heat, sunlight, or even fluctuating temperatures, its protective and presentational capacity is affected, as it breaks or peels, making it unlikely to protect and enhance the surface of the box.

These are just a few of the limitations of water-based coatings, which seem nothing compared to their unparalleled benefits.

So, if you are someone who wants to apply a smooth and protective layer of AQ coating on personal boxes, make sure to share your needs or requirements with the manufacturers for a better selection.

At this point, you see the benefits and limitations. Now, some people thought, okay! What are the other options as an alternative to aqueous, right?

For this, here is a short comparison between the most asked-for alternatives to water-based coating.

Aqueous Water Coating In Comparison To UV & Varnish

What is the difference between aqueous coating, UV, and varnish? This makes many manufacturers and packaging printers overwhelmed.

But now it is no longer the issue, as we are going to break down each option. Here is the detailed guide:

Final Thought

Now, you! Yes… The one who has already read the entire article and is currently looking for the final outcomes. By understanding all about aqueous coating. You will clearly find out how it would be a perfect fit for you by considering the several factors, which include:

1. Aqueous or AQ is a water-based coating, where water is the main component, mixed with polymers.
2. It is a cost-effective and environmentally friendly option.
3. Used to improve protection and enhance presentation (based on the needs from glossiest to dullest) while also having some limitations.
4. It has some ups and downs compared to other coatings, like UV, in terms of resistance.
5. And lastly, it is one of the preferred or demandable coating options among many packaging manufacturers and buyers.

By understanding what an aqueous finish is in printing and packaging, its features, and its many other related things. Hopefully, you will find your answer.

So, if you have any questions regarding coating or any other packaging factor, do not hesitate to contact us. Our expert packaging engineers are here to assist.