Carpet color loss is a universal challenge. Ultraviolent rays from the son can naturally cause color fading. It’s pretty impossible to shield your carpet from UV rays (however, there is special glass (Low-E) that can help with this).
However, there are other things that cause carpet color loss that you have more control over. Chemical color loss happens due to chemical reactions. There are two types of chemical reactions: reduction/oxidation (REDOX) and Ionization.
REDOX reactions, which are caused by either:
- Reducers from sodium hydrosulfite
- Oxidizers, such as from peroxides
Ionization is caused by acids like hydrochloric or sulfuric. Ionization only impacts nylon not wool. Hydrochloric registers a high chlorine content. Alkalies come from concentrated hydroxides like oven and concrete cleaners. Many of these will show up as oxidizers.
What colors fade first
Generally, color loss occurs one primary hue at a time, especially for natural color loss. The general order is for blue to go first, followed by red then yellow. This means that a brown carpet will first turn orange, then yellow and finally white. There are specific substances that destroy only one color. Formaldehyde destroys red dye. Formaldehyde is found in wooden floor products. Freon destroys yellow dye. Freon was the common coolant used in air-conditioning
Measuring for chemical reactions
You can measure REDOX and ionization on meters. Measure REDOX on an oxidation reduction potential (ORP) meter. Negative numbers indicate a reducer while the positive values indicate an oxidizer. Mild reducers for removing coffee or tea have ORP values of approximately of -200. Strong red dye stain removers have ORP values of less than -450. Three percent hydrogen peroxide has an ORP value of approximately 360. Strong peroxide stain removers have ORP values of 450 and more.
Chemical color losses
Chemical color losses typically have a pH that is more than 0.3 difference from the surrounding carpet. The pH and sometimes the ORP values will often need to be neutralized before new dye can be reapplied.
The best neutralizers for alkali pH values is acetic acids; the best neutralizer for acidic residues is ammonium hydroxide. That is because both are volatile. However, other forms of mild acids or alkali can work too. You may want to avoid ammonium hydroxide when chlorine is in the carpet. This could create a poisonous gas. Measure chlorine with a chlorine meter, which looks and operates like the pH and ORP meters.
Color loss occurs in both nylon and wool carpet. Both are usually dyed with acid dyes. This can cause issues with alkalinity, especially with wool carpets.
Nylon 6 is more prone to loss color than Nylon 6,6. The Nylon 6 is easier to re-dye. A stronger reaction resulting in color loss is more prevalent than wool.
ORP values of less than -300 or over 400 can destroy the color as well. A mild reducer is the best neutralizer for a strong oxidizer, and a mild oxidizer is the best neutralizer for a strong reducer. Mixing strong reducers and oxidizers together on the carpet will create a lot of heat and poisonous gas.
Wool fiber cannot be harmed by strong acids, but its dyes are still susceptible to damage. It bleeds at slightly acidic pH values. Most wool will measure pH 5.5. That is because it is anionic, and its polarity starts to flip when its reading climbs over 5.9.
Carpet color loss is the result of both natural and chemical reactions. It’s much harder to control UV rays. Instead it’s more prudent to protect carpet color from chemical reactions. If you have any questions about carpet color loss and how you can better protect your clients’ carpets, please get in touch.