The contrast between waterborne coatings and conventional solvent-borne coatings is based on the liquefying agent used in the formulation. In waterborne solutions, water is the carrier for the resin instead of a chemical-based solvent. This distinction makes waterborne coatings safer and more environmentally sound because fewer VOCs are emitted than with their high performance, reasonable cost and what has become more important is sustainability and lifecycle analysis.
There are many articles that are written around the topic of waterborne coatings, some of which are included in the footnotes, and in all cases, the reader should peruse the UL Solutions Prospector® Knowledge Center[1].
Rather than repeat what has been written, I have included citations for articles along the same lines of this topic. I suggest that you start with “Formulating Waterborne Coatings: a Checklist”, written by Dave Fuhr seven years ago for UL Solutions. He does an excellent job asking the right questions such as; what you formulating, what is the technology, what surfaces, what attributes are required, properties and application methods.[2]
The global waterborne coatings market size was valued at USD 57.67 billion in 2022 and is anticipated to grow at a compound annual growth rate (CAGR) of 5.6% from 2023 to 2030. The growth is driven by the development of construction activities globally. Rising construction undertakings due to rapid industrialization and urbanization across the globe are anticipated to drive product demand over the projected period. The disproportionate shift in coatings trend from low or high-volatility organic solvents to complete solvent-free coatings that have fewer emissions is likely to contribute to the growing mandate for waterborne coatings in residential as well as commercial coating applications. Interior and exterior wall paint formulations mainly rely on waterborne coatings.[3]
Types of Waterborne Coatings
Below are some of the various types of waterborne coatings that are available in the market today:
- Water-soluble paints– contain water-soluble resins whose individual molecules dissolve completely in water. The resins are usually produced via polycondensation or polymerization reactions in an organic medium. Therefore they mostly contain organic co-solvents like alcohols, glycol ethers or other oxygen-containing solvents that are soluble or miscible with water, although some coalescing solvents or plasticizers are relatively immiscible in water. The resins used include polyesters, polyacrylates, alkyds, epoxies and epoxy esters. These paints provide high gloss, a high level of corrosion protection, good pigment wetting and good stabilization.
- Water-dispersible paints or colloidal coatings– contain small clusters of insoluble resin particles that are suspended in water using mechanical agitation. Small quantities of organic solvents are used as coalescing agents, which evaporate on drying. The resins used in these types of dispersion paints include vinyl propionate copolymers, vinyl acetate copolymers, acrylate-methacrylate copolymers, and styrene-butadiene copolymers and polymers. Colloidal dispersions are used mainly to coat porous materials such as concrete or paper.
- Emulsions/latex paints– are quite similar to water-dispersible paints. The main difference is that the resin clusters in emulsions tend to be larger, and an emulsifier is required to keep the clusters in suspension. The resins used include styrene-butadiene copolymers, acrylics, alkyds, polyvinyl acetate, and polystyrene. These paints possess increased permeability.
- Water-based alkyds– These coatings tend to take longer to dry than solvent-borne alkyds; however, the end result has similar gloss, flow and leveling properties. They are very versatile as they can be thinned with water to almost any viscosity. Water-based alkyds can be applied with spray or dip applications and are one of the less expensive VOC-compliant coatings.
Advantages of Waterborne Coatings over Solventborne Coatings
The key advantages to using waterborne coatings are listed below:
- Waterborne paint is cleaner for the environment as it contains fewer or no VOCs. During the drying process of most paints, VOCs are released into the air as fumes and can linger for a long time following use. In waterborne paint, VOCs do not persist in the air for as long, thus being much kinder to the environment.
- Waterborne paint is less of a hazard than solvent-based paint due to being less flammable.
- These two are the crude advantages of waterborne coatings and avoids all the intricacies of formulations.
Allgaragefloors.com
As nice as it would be to keep things simplistic, it would be remiss not to explain the differences between the following terminology. There is a difference between VOC’s, HAPs (Hazardous Air Pollutants) and Exempt Solvents. And although VOCs are usually viewed as man-made, there are many examples of naturally-occurring VOC’s.
Lower VOC paints are those paints that contain less than 50 grams of volatile compounds in one liter of paint, according to the Green Seal Standards. Zero VOC paints contain less than five grams of volatile compounds in one liter of paint. Although that seems misleading, I think most people can intuitively see that zero is less than five in this case. There are other types of paints that do not contain any volatile organic compound such as chalk or milk paints.
Because of the adverse effects of volatile organic compounds, paint manufacturers are now focusing more on the production of low VOC paints. Natural materials are also being used to produce paints because they do not have any harmful effects on human health.
Benefits of Using Low VOC Paints
There a lot of benefits that you can enjoy when you use low VOC paint in your home as discussed below:
- Cleaner Air
When you use paint that has lower levels of volatile compounds, the quality of your indoor air is significantly improved. If you use a low VOC paint option, you won’t be worried about inhaling toxic fumes after or during the painting process. Remember that paints can cause various health problems from respiratory issues to aggravating allergies that can be detrimental to your health.
- No Strong Odors
When painting the inside of your home, the odor coming from the paint can be a hindrance for you: it can keep you from completing your painting project on time. Paints dry slowly, and the scent of paints that have a high concentration of volatile compounds can stop you from returning to your home. Low volatile organic compound paints do not violate your indoor air.
- Cost Effective
Low VOC paints are affordable, and you can get them at your nearest hardware store. They are not as expensive as most people wrongly believe. In fact, many stores sell them at the same price as the other paints.
- Durable
Low volatile organic compound paints are more durable than other types of paints on the market.
This just provided a glimpse of waterborne coating technology. The footnotes and endnotes provide much for information than could be provided in one article.
[i]Formulating waterborne coatings: adding color (ulprospector.com)
[ii]Recent Advances in Waterborne Coatings Technology (ulprospector.com)
[1] Raw Material and Ingredient, News, Articles and Videos | Prospector (ulprospector.com)
[2] Formulating waterborne coatings: start with a checklist (ulprospector.com)
[3] Global Waterborne Coatings Market Size & Share Report, 2030 (grandviewresearch.com)
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