About latex coatings
One of the drives across industries of all kinds is to reduce the environmental impact of their processes, and latex coatings are conducive to that goal. Latex itself is a naturally occurring compound, and it is often used as a protective coating on work gloves and other equipment. However, in liquid coatings, synthetic compounds are used to replicate the protective properties, creating a free-flowing liquid coating that can be sprayed easily. While they technically have no latex in them, we still refer to water-based products as latex coatings today, and unlike oil-based alternatives, these coatings do not emit large amounts of gases during the drying and curing process.
As a water-based paint, latex coatings are more cost effective than many alternatives, while providing a tough, weather resistant finish that is available in a myriad of finishes, covering every color imaginable along with a variety of gloss, matte and satin looks.
What are latex coatings made from?
In the early days of water-based paints, natural latex as the binder, but today modern coatings used a synthetic compound, usually either an acrylic or vinyl alternative. Natural latex is a kind of rubber, and these synthetic alternatives are formulated to emulate the flexibility and smooth finish of latex-based products.
Alongside the latex type solids, the part left once the coating has dried, latex coatings also contain pigments that provide the color and influence covering ability. Finally, the carrier liquid for latex paints is made up primarily of water, which is why latex coatings are relatively odorless compared with other coatings that use oil-based liquids.
Latex coating advantages
These types of coating are easy to apply and fast drying, making them ideal for a production process, The lack of gas emission during the drying process is particularly beneficial and can have a significant impact on the time and cost of the painting process.
Latex coatings exhibit excellent corrosion resistance, and they are often used to protect metalwork from harsher environments where corrosion would be an issue. The finish is tough and scratch resistant, providing a long protection life. With such a variety of colors and finishes, they also provide aesthetically pleasing looks for applications where that is important and can retain those good looks over an extended period in outdoor use.
Highly weather resistant, the finish will not degrade over time, with colors remaining vibrant, avoiding the fading in UV light some finishes suffer from. Finally, a lack of VOC emissions means that latex coatings are more environmentally sustainable that alternatives, and they avoid the regulatory processes that oil-based coating processes must follow, cutting costs.
Challenges of using Latex Coatings
All latex coatings have excellent protective properties, and offer excellent adhesion to the surface being painted, but only with proper preparation. Metal surfaces must be primed first, adding an extra step to the process
In addition, they tend to have higher levels of shrinkage during the drying process than alternatives and do not handle excessive temperature changes too well, which can result in problems over time. These challenges can be avoided though, shrinkage during the drying process need not cause issues if allowances are made during the application, likewise, by choosing the appropriate coating for each application, simply avoid using latex coatings in situations where they would be exposed to significant temperature changes.
Latex Coating Application
Latex coatings are easy to apply, thanks to fast drying and excellent coverage, requiring few coats to get even, effective protection for any item. They cannot adhere to metal directly, so any item being coated must be primed before the coating process, beyond that there are several approaches that have proven to be cost efficient and very effective in production processes.
The most common approach for applying latex coatings is through spraying. Modern spraying uses low pressure high volume (LPHV) spray guns, which can be operated by hand or automated, depending on the production facility and product. Paint is thinned to ensure even atomization and offers a cost-effective coating process.
This approach provides a simple, reliable solution that delivers a high-quality finish, minimizing paint waste and allows for rapid color changes if required. However, for more complex shaped products, it can be a challenge to get an even coating on every surface. In particular, if the item has internal corners that need spraying, it is extremely difficult to avoid paint buildup in these enclosed areas.
Airless spraying, also known as high pressure spraying, is an alternative approach that is widely adopted when using latex paint for corrosion protection and relies on building extreme pressure in the coating and forcing it through a small nozzle. For un-thinned latex coatings, this needs to be as high as 250 bar pressure to produce the atomization and even coating required. This type of spraying reduces overspray waste and produces a thicker finish than other methods, however it can leave a textured finish that some may not like.
Finally, dipping is frequently used in the application of the coating. Here, the object is dipped into a tank of the coating. To ensure complete coverage, the metal object can be used as an anode in an electrical circuit, with the coating becoming the cathode. As the object is introduced into the tank, latex coating is attracted directly to the metal part, ensuring every part of the surface has coating adhered. For complex shapes with internal corners and other challenging shapes, this is the most effective approach and is commonly used in vehicle coatings.
Whichever approach is used, latex coatings deliver exceptional coverage and value. They have been used as protective and decorative coatings for many years and remain popular today. Since the adoption of synthetic alternatives to natural latex, these coatings can be tailored to provide a range of qualities that suit specific applications. In all cases, the smooth finish, vibrant colors, and hard wearing, scratch resistant surface mean that they are used in a broad range of applications. From garden furniture and outdoor signage, marine environments, providing corrosion resistance for industry, and protecting children’s play park equipment, latex coatings can be found throughout daily life.
