8/12/2019 Phenolic Yellowing of Textile

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Phenolic yellowing of textileby Chris on Nov 6th inAlgemeen

Some textile materials are sensitive to phenolicyellowing especially in the light shades. It is not the only yellowing

risk. Through good agreements this can be prevented

Yellowing of textile is caused by a reaction. There are different kinds of yellowing (and other forms of

discolouration). It can happen in different stages: during the production process, when storing and when using the

goods. It can also have different causes.

Often, yellowing concerns a reaction with phenols. This we call phenolic yellowing or gas fading by NO2. These

phenols are present in packaging materials. Under certain conditions contact with the textile causes yellowing.

When this type of yellowing is discovered in an early stage, the process can still be reversed.

Which textiles have a propensity to yellowing

Basically, in all textiles (and all colours) yellowing/discolouring is possible, but it is specially visible in the very light

colours, so white and pastel colours. In the darker shades you can only see the colour getting a bit duller.

Other kinds of textile yellowing

* yellowing by (accelerated) ageingof fibres, e.g. by long term exposure to heat or light, or sometimes even by

blending certain fibres

* yellowing byindustrialadditivessuch as softeners (washing), lubricants, resins, optical brighteners (OBAs), or

salts

* yellowing by ozone (denim), sulphur dioxide or other elements (pollutants) in the air

* yellowing by contamination from theconsumer (perspiration, parfumes, lotions, medicines, detergents, washing

softeners, starch, etc.)

Where and when does it happen

Phenolic yellowing is mostly occurring when storing fabrics or garments, so in the warehouse.

Plastic packaging material, like polybags, can contain BHT (butylated hydroxy toluene). This is an antioxidant that

prevents ageing of the plastic. This BHT can be transferred to the fabric. Also from carton boxes a phenol

(derivate) can be carried over to the textile. It can react with the nitrogen oxide (NOx) in the air and forms

nitrobenzenes or quinone (or chinone), which is a yellow chemical substance.

The process needs alkaline (so non-acid) conditions. A cause of alkaline conditions can be insufficient washing out

and neutralising of chemicals used for bleaching and dyeing.

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8/12/2019 Phenolic Yellowing of Textile

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More about phenol

For general information seeen.wikipedia.org/wiki/Phenoland for more technical details, see:Toxic Substances

Portal.

What to do about it

Some examples:

* make sure the fabric has the right acidity: use acid finishes instead of alkaline and/or apply an acid finish after

having applied any alkaline finish

* avoid volatile antioxidants in packaging material that come into contact with the textile

* use phenol free carton boxes

* minimalize the quantity of nitrogen oxide in the warehouse

* further:

There are tests that indicate the risk of yellowing of fabrics. Put the right test standard and requirement in your

specifications, e.g. in the material requirements. Already for a long while the so-called Courtaulds method exists,

which is a quite expensive method. From 2007 the method is standardised in an international standard.

Convenient. For a maximum effect, make sure the required value is realistic and common in trade.

Also requirements of packaging materials are possible

https://en.wikipedia.org/wiki/Phenolhttps://en.wikipedia.org/wiki/Phenolhttps://en.wikipedia.org/wiki/Phenolhttp://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=27http://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=27http://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=27http://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=27http://www.quality-assistance.nl/wordpress/wp-content/uploads/2012/11/yellowing-of-white-trousers-2A.jpghttp://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=27http://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=27https://en.wikipedia.org/wiki/Phenol