BHT
Yellowing
The symptoms described mainly occur in the USA and places that use
their underlay but not thank goodness here in the U.K. Our (pads)
underlays are usually rubber/latex based and do
not use BHT based chemicals. There is nothing I can find that states
there is any problem with BHT, so do not be alarmed in any way.
So.......
BHT(Butylated Hydroxy Toluene) is a common preservative used in many
plastics including carpet backing and rebond pad (cushion). It is even
used as a preservative in bread. Many believe that BHT is the
cause of the problem. Others believe that the problem is the stain
blocker itself - reacting with nitrous oxide gas and turning yellow.
Regardless of the cause,
most of the problems have been on carpets in areas of low air
circulation such as in closets, under low lying furniture or under throw
rugs.
To cure the problem, most fibre producers recommend a 105 solution of
citric acid to remove BHT yellowing.
One chemical usually used is "Brown Out". The primary
acid in "Brown Out" is citric. Using "Brown
Out" at 1 part product to 2 parts water will cure this condition.
Simply spray the affected area heavily with this solution, allow at
least 15 minutes for the yellow to disappear, and do one single wet pass
with water (no detergent) and two dry passes. This removes the excess
"Brown Out" but leaves enough behind to reduce the likelihood
of the yellowing returning.
Compensation should be sought as well as a full clean and new
application of a stain inhibitor, also the manufacturers should also
ensure in writing they will continue to warrantee their product.
