Yellowing Epoxy-based Dry Erase Paint vs. Water-Based Dry Erase Paint

Introduction: Due to the chemical structure of their ingredients, epoxy-based dry erase paints are susceptible to a type of discoloration known as yellowing or “ambering” when they’re exposed to ultraviolet (UV) light for some time. Even when chemicals called UV light stabilizers are added to their ingredients, epoxy-based coatings still turn yellow with time and require removal and recoating, especially when more severe problems arise, such as delamination (fracturing into layers), peeling, loss of surface sheen, and chalking, or the formation of a powdery layer on a coating’s surface. In contrast, our quality dry erase paint is composed of a highly durable, flexible, and waterproof two-part water-based aliphatic polyurethane formulation, which, unlike epoxy-based dry erase paints, is highly resistant to UV radiation, and so is not subject to yellowing or the other problems common to epoxies.

Epoxy-Based Dry Erase Coatings and Yellowing

Like most other materials on Earth, epoxy resins such as those used in many of today’s dry erase paints change when subjected to ultraviolet light from the Sun or other sources. Even the UV light from seemingly harmless fluorescent lights can produce changes in epoxies, the most obvious being a form of discoloration known as ambering. When rays of ultraviolet light from the Sun or artificial lights shine on an epoxy-based dry erase coating, they gradually damage the complex chemical compounds known as polymers in the coating’s resin, producing a yellow or amber hue on the formerly pristine dry erase surface. Even epoxy-based dry erase coated surfaces that are initially crystal clear and transparent or pure white (if zinc oxide is part of the ingredients) will inevitably and sometimes quickly take on an unsightly-looking shade of yellow.

Initially, yellowing appears as a light hue over the entire dry erase surface and then gradually deepens till it attains a darker brownish-yellow color. Indoor epoxy-based dry erase coated surfaces typically start to yellow in six to twelve months after they’re applied, even if they’re composed of paints containing a UV-stabilizing chemical additive because such additives only slow down the pace of yellowing but cannot prevent it. This color change is unavoidable because epoxies, which belong to a group of organic compounds known as aromatics, are unable to resist the effects of ultraviolet light.

This quality of powerlessness against the impact of ultraviolet light is known as being “UV active.” The molecules of UV-active chemicals need strong atomic linkages, which is common in aromatic compounds like those contained in epoxy-based dry erase coatings. While epoxy resins have excellent chemical and physical qualities, their toughness and functioning are severely lessened by the action of UV light on their chemical structures, so yellowing, cracking, and loss of durability are bound to happen. Oxygen radicals are formed as oxygen molecules in the atmosphere are subjected to ultraviolet light. These unstable molecules contain oxygen and react easily with other molecules, so they readily attack and react with the surfaces of epoxy-based dry erase coatings, causing yellowing and the other problems mentioned above.

Thus, while they have good chemical resistance and electrical properties, good adhesion to metals, and good resistance to water and physical shock, epoxy resins are highly susceptible to UV light damage, so their durability is greatly lessened when they’re exposed to sunlight or even artificial radiation from fluorescent lamps and other sources. In other words, epoxy resins can’t resist the impact of ultraviolet light on their original color and appearance. In fact, epoxy-coated surfaces have even been known to undergo yellowing when they’re kept in total darkness.

UV Light Stabilizers Delay the Inevitable

Many epoxy resins currently on the market contain UV light stabilizers to guard against the problem of ambering or yellowing, along with the other issues that epoxies are susceptible to, such as delamination (fracturing into layers), peeling, loss of surface sheen, and chalking, which is the formation of a powdery, easily crumbled layer on the surface of a coating, usually caused by exposure to ultraviolet light or other forms of energy. Epoxy resins that are continually subjected to ultraviolet light are also prone to cracking, which, in the end, leads to failure and the need to remove the degraded coating and recoat completely.

For these reasons, UV light stabilizers are necessary additives for epoxy-based dry erase coatings. They are generally effective, except for yellowing, which the additives can delay for a time but can never be eliminated. Silicone-based epoxy resins have better UV-light resistance than other types of epoxies, but they come at an extremely high price and are thus cost-prohibitive for most customers. So, when choosing a dry erase coating, buyers need to be aware of and avoid products like epoxy-based dry erase paints containing aromatic compounds that yellow, and eventually experience other problems leading to failure, including delamination, chalking, peeling, and cracking.

Superiority of Top Dry Erase Coating’s Chemical Structure

As discussed above, epoxy resins contain aromatic molecular groups that strongly absorb light in the ultraviolet range of the light spectrum, putting their chemical structures at high risk of being degraded by such light. The light stability of epoxy resins may be improved by including additives known as UV stabilizers or UV inhibitors. Still, epoxies will never reach the same level of ultraviolet light resistance as that possessed by aliphatic acrylic urethane formulations, such as those of our premium clear and white ReMARKable dry erase coatings, which retain their bright, sparkling appearance for ten-plus years of continuous writing and drawing, if properly cleaned and maintained with microfiber materials and a water-based dry erase cleaner.

Aliphatic acrylic polyurethanes like those in our premium dry erase coatings are composed of multiple straight chains of urethane, a synthetic crystalline chemical compound with tremendous strength and elasticity. The molecular forces in polyurethanes are spring-like and feature strong attractions, causing polyurethane compounds to be highly flexible, tough, and long-lasting. Coatings like our high-end dry erase paints made from polyurethanes like aliphatic acrylic urethane typically have high tensile strengths and molecular bonds, so they continue to hold up even under extremes of temperature and physical stress. These qualities make our top-quality dry erase paints appropriate for application in all environments and withstand long-term use with the proper care and maintenance.

Top-quality Dry Erase Coatings Resist Yellowing

All paints yellow to varying degrees when exposed to ultraviolet light; however, since our premium dry erase coatings are not epoxy-based but instead are aliphatic acrylic urethane formulations, they’re among the most light-stable of all dry erase paints on the market today. Therefore, while some yellowing may occur with our coatings, it is so subtle that it’s not visible to the naked eye and requires special laboratory equipment to detect, so it doesn’t affect the appearance of a finished dry erase-coated surface. The aliphatic nature and excellent light stability of our premium dry erase paints, and the UV-inhibiting chemicals they contain make our products about as light stable as possible at the current research and development stage in dry erase paint manufacturing.

Aliphatic refers to organic compounds in which carbon atoms form straight open chains, as in polyurethane, not aromatic rings, as in epoxy resins. This quality of having open-chained atoms makes aliphatic urethane products like our premium dry erase coatings resistant to ultraviolet radiation and, in turn, to yellowing and the other problems epoxies are prone to. In aromatic compounds such as those in epoxy-based dry erase paints, the carbon atoms are joined in a ring structure, making almost all such compounds susceptible to changes caused by ultraviolet rays from the Sun and artificial lighting. So, when choosing a dry erase coating for your office, school, private home, or other venue, it’s wise to go with ReMARKable, an industry leader with a tough, long-lasting urethane formula that will never yellow, crack, or peel for its entire lifespan.

Summary

Article Name

Yellowing Epoxy-based Dry Erase Paint vs. Water-Based Dry Erase Paints

Description

Discover the difference between ReMARKable's innovative whiteboard paint and epoxy-based options. Learn about their features, pros and cons.

Author

Susan Anspach

Publisher Name

ReMARKable Whiteboard Paint

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