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Carpet Cleaning Issues - Carpet construction, upholstery cleaning, stain removal, equipment, events, etc.


Posted by rob_s (rob_s), 28 January 2004
Hi, could anyone out there explain to me what B.H.T.  (butylated hydroxytolune) is?  Where and how it occurs and any solutions for this problem.


Posted by woodman (woodman), 28 January 2004
Hi Rob

I believe this is a chemical preservative used in the production of animal feeds and by all accounts can quite dangerous.

What problem are you intending to try and cure?

Posted by rob_s (rob_s), 28 January 2004
B.H.T. I believe,  is used in the manufacture of synthetic fibres and causes yellowing as described in Prochems' spotting guide on their website.  Just wanted an explanation of what BHT yellowing is and if anyone knows of any ways of curing it.

Posted by Nigel_W (Nigel_W), 28 January 2004

It is a long time since I had a BHT problem so I am dredging deep in my memory banks.

I believe in the past the best remedy was to use citric acid to cure BHT yellowing ,although I have a feeling that Sodium Metabisuphite? (Spray and Go) might be better these days.

The last one I had corrected itself by uncovering the yellowed area. Over time it naturally disappeared.

Posted by rob_s (rob_s), 28 January 2004

 Thanks for that information, very helpful.

Just wonderd if any one new the cause of B.h.t. yellowing.

Posted by Robert_O (Robert_O), 28 January 2004
Hi Rob_s

I will try to explain my understanding of the Cause of Butyl Hydroxyl Toluene (if that is how it is pronounced or spelt)

BHT (or Phenolic Yellowing) is, as I understand it caused by the chemicals used in the production synthetic materials and there prolonged off gas exposure to fibres.

If a new carpet is fitted you usually get that distinctive odour of 'new carpet' for several weeks after installation. The carpet will release these chemical reminants in to the atmosphere, which will gradually dissipate over a period of time. I think that I would be safe in assuming that they would be harmless to health at these low levels.

If however a carpet has been covered over and sealed in by say a tv cabinet or a flush fitting sofa, this will inhibit the aeration of this off gas creating a chemical stagnation and may cause a yellow type of discolouration.

I have also seen this phenomenon occur on wool Berber carpet, which may suggest the synthetic backing off gassing or other components such as latex.

You also need to consider other possibilities, like Cellosic Browning, but these can be discussed with the client to find out whether the carpet has undergone any excessive wetting or dampness.

So basically it is a reaction between the fibres the off gassing chemicals of the manufacture/dyeing process and environment factors also.

This is how I understood the information that I have been given, but I am ready to be shot down in flames.

It would be interesting to see other peoples veiws on this.

I hope that helps.


Robert Olifent

Posted by rob_s (rob_s), 28 January 2004
   Thanks for the information on B.H.T. Robert-o.
   Is there a product other than what Nigel suggested,that removes this kind of yellowing.

   rob-s Huh        
Posted by Shaun_Ashmore (Shaun_Ashmore), 28 January 2004
Chuck some bleach on it Roll Eyes
Posted by Nigel_W (Nigel_W), 28 January 2004
You are spot on there Robert O. The last one that I mentioned was a Sofa with skirts that formed an air tight seal at the floor.
It was a carpet sourced in America that gave off the BHT gas that caused the yellowing. By moving the sofa for a few months the yellowing gradually disappeared.

Posted by Ivar_Haglund (Ivar_Haglund), 28 January 2004
Citric Acid  works great  sometime the stain just becomes part of the carpet.

almost forgot

NOT acidic acid like fiber rinse does not work well

IVAR Shocked Shocked Tongue
Posted by Dynafoam (Dynafoam), 28 January 2004
Since the areas of B.T.H. yelowing tend to be extensive, I would not recommend the use of Spray'N'go, or any other Sodium Metabisulphite based product, due to the fact that the fumes given off are a bronchial irritant and could cause some distress to anyone exposed to the over a prolonged period.

As our Norwegian friend has said, citric acid, through its' mild bleaching effect can be beneficial.

If you do not have access to this, Prochem Oxybrite + Fibrebuff + B105, mixed & used as per  celulostic browning instructions, can be very effective.

Posted by Derek (Derek Bolton), 29 January 2004
Hi Guys

BHT is not simply restricted to carpets..Little '0' from Nottingham has described it rather well... he's been reading his NCCA magazines again.

Some years ago there was a rash of upholstered furniture which began to show evidence of phenolic yellowing. It was found to eminate from the interior foam fillings...why should this happen on some and not others?

I am probably going to get shot for this next remark... .

Some manufacturers were using cheap foam  in an effort to cut their manufacturing costs. When exposed to air the foam went from a whitish shade to deep yellow in a matter of weeks and the sulphur residues migrated to the surface of the fabrics...on dark fabrics it often resembled nicotine staining... citric acid did remove the staining but it would return unless the offending foam was replaced.... haven't seen it for a while on furniture thank goodness

Posted by woodman (woodman), 29 January 2004
Sorry rob threw me with with the spelling Roll Eyes

Derek: Had the same problem a few years ago with new furniture in showrooms,caused by cheap foam fillings 'gassing off' (like some on here Grin).

Can also be found in Polyprop carpets in manufacture and underlays but not so much now because of the problems it causes..

Posted by Derek (Derek Bolton), 29 January 2004
Hi Woody

Yes, I too have seen yellowing on fabric in a showroom

Posted by SMP (SMP), 29 January 2004
Hey Derek,
I note in a FSB magazine that Customs are having a lot of trouble with sub standard suites being smuggled into the country.  Could be that we will see a rash of yellow suites in the near future?? Sad

Posted by Derek (Derek Bolton), 30 January 2004
Hi Steve

What is the FSB magazine?

A great many of the fabrics used in todays' furniture is made abroad, sometimes in several countries...i.e. made in Israel, shipped to the US for printing then sold to the UK.

Reading one of my monthly magazines in each issue there is a UK dyehouse/manufacturer closing down and moving to the far east...cheaper labour out there.

I question whether they in fact meet the BSI standards for upholstery fabrics....I have serious doubts with a some of them


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