Flowcrete explains the occurrence of amine blush on industrial floors and provides suggestions on detecting and preventing the problem.

A common industrial flooring problem, amine blush is a normal chemical reaction between amine-curing agents and carbon dioxide in the presence of moisture, resulting in the formation of a carbonate that appears as a greasy film on the surface.

Amine blush may be caused by high humidity, the presence of excess carbon dioxide in the atmosphere, low curing temperature, and improper and inadequate mixing of the resin and hardener.

Detecting amine blush

Amine blush can be detected by lightly rubbing the surface to reveal a greasy or waxy film or by checking the surface for a lower gloss, oily or greasy film, haziness, yellowish or whitish tint or a patchy appearance when viewed at different angles. It can appear as greasy white spotting or even in the form of salt-like crystalline deposits.

How does amine blush affect floors?

Amine blush can cause imperfections in the coating surface, compromised cleanability, decreased stain resistance, surface tackiness, loss of gloss, poor adhesion, difficulty in re-coating, or faster yellowing.

Preventing amine blush

Generally, most epoxies can be subject to blushing under certain conditions; however, some epoxy coatings are more prone to blushing than others.

Precautions to avoid formation of amine blush include adhering to all the recommended induction or ‘sweat in’ times in the product literature after mixing; avoiding sources of direct combustion such as direct-fired heaters, forklift trucks, welding equipment and combustion engines; ensuring coating products are stored in warm conditions; and checking environmental conditions and applying materials when the temperature is a minimum of 50°F above dew point and rising. Additionally, avoid using propane heat in closed environments because they emit CO2.

Amine blush should be removed immediately so that effective bonding between the substrate or with additional coats of epoxy is not prevented.

Image: Amine blush is a common industrial flooring problem