Carpet Yellowing

Yellowing of carpet fiber is often perplexing to the consumer and the carpet professional alike. Consumers often insist yellowing is a result of a manufacturing defect and the carpet professional has a difficult time convincing the consumer otherwise. Yellowing of carpet fiber has become more commonplace in recent years due to the development of stain resist technology. Consumers are now able to purchase lighter shades of carpet with less worries about the cleanability of the fiber. These new, lighter colors hide yellowing less than the darker colors of the past.

Identifying the source of the yellowing can sometimes be elusive. There are a number of causes for yellowing of synthetic carpet fiber. Yellowing can be the result of one isolated source or a combination of sources.

While permanently eliminating the reoccurrence of yellowing can be difficult without identifying the source, a temporary solution can usually be achieved by applying an approved acid-rinse solution to the face fiber. An acetic acid solution or a citric acid solution should be used by a carpet cleaning professional to remove any yellow discoloration. A ten (10%) percent pharmaceutical grade citric acid solution often works well due to the residual benefits of the citric acid solution. In some cases, the consumer may use a solution of one cup water mixed with one cup white vinegar to neutralize small areas of discoloration. Any other consumer application should be discouraged. The application of any detergent solution should also be discouraged since some types of yellowing can be permanently "set" by the high alkalinities of many detergent solutions.

Possible Causes of Yellowing

BHT (butylated hydroxy toluene) or BHA (butylated hydroxy anisole) is probably the most commonly recognized yellowing situation and probably the most over-blamed. BHT serves as an ultraviolet inhibitor and an antioxidant. It was used through the years as a preservative in polypropylene yarn systems, carpet adhesives, some latex formulations, various backings and backcoatings, and many other consumer products. BHT is considered non toxic and is even contained in many food items.

About the Author
Michael Hilton was the original creator of Carpet Buyers Handbook. Having owned and operated a carpet wholesale company, Hilton has a vast knowledge about all-things carpet related as well as other types of flooring.