This document discusses phenolic yellowing in textiles, which is discoloration caused by the reaction of oxides of nitrogen with yellowable phenols. It describes the phenolic yellowing test method, which exposes textile samples to a methanol solution containing phenols and oxides of nitrogen to assess their potential for yellowing during storage or transport. Light colors and whites are most affected, showing visible yellowing, while dark colors become duller. The test maintains controlled environmental conditions and uses a standard scale to evaluate the intensity of yellowing. Proper test procedures and avoiding phenols in chemicals can help prevent yellowing issues in textile production and use.

1. Epyllion Testing lab Ltd Your Partner in Textile Testing
Phenolic yellowing in textile
It is the discoloration of textiles caused by the action of oxides of nitrogens on yellowable phenols.
For phenolic yellowing to take place three components are required; yellowable phenols (OH),
oxides of nitrogen (NOx) and certain pH conditions.
During the production process ,when storing and when using the goods .It can also have
different cause .Often ,yellowing concerns a reaction with phenols .This we call phenolic
yellowing or gas fading by NO2.
Apart from the frequent attack on white or pastel shades, dark shades are also affected, which
becomes duller in appearance. It can occurs by fiber degradation , by color break down by chemical
destruction .
The test papers are impregnated with a methanol solution containing the phenolic compound and
oxides of nitrogen.The pH conditions are provided by the material under test.The yellowing
comes from the phenols. Chemically, the yellow substances form through nitration and/or
oxidation of specific phenolic substances often found to be present in antioxidants and
preservatives.The control fabric goes yellow (dark lemon), during the test, ensuring that correct
test conditions have been used.BHT-free film is utilized during the test to ensure that the
yellowing that has occurred is not due to products within the film.
 What is the Test Method Used for?
The phenolic yellowing test method is a simple predictive test, typically used to assess the potential of
white or pastel-coloured textiles to transit or storage yellowing. It is specifically for phenolic yellowing i.e.
the discoloration of textiles caused by the action of oxides of nitrogens on yellowable phenols. The test
is not intended to deal with many other causes of discoloration, i.e. migration or fading of optical
brightening agents, gas fume fading, the oxidation of fabric lubricants and so on.

2. Epyllion Testing lab Ltd Your Partner in Textile Testing
 Outline of Test
The risk of yellowing is evaluated by a contact test. Each test specimen is folded between a phenol-
impregnated test paper. The test package consists of 5 test specimens and one standard control fabric
wrapped and sealed in BHT-free polythene film. A Perspirometer maintains constant pressure on the
package, and an incubator provides the specified environmental conditions. On removal from the
incubator the specimens are compared with their original and the intensity of yellowing assessed using
the standard Grey Scale for Assessing Staining.
 Which color affected most ::
Basically in all textile all colors affected by this .Specially it is very visible on light color and white .When
it is dark color we found shade little bit duller .
 Out of the box it can be happened::
If fabric long term exposure to heat or light or some time even by blending certain fabric .Visible when
we use softeners ,lubricants ,OBA or salts .Some time by ozone [denim]or other elements in the air
.Some times by using perfumes ,lotions, medicines ,detergents ,washing softeners ,starch etc .
 What can we do to avoid it ::
However quality is a cloudy topics .But if your product make into yellow that is not comfortable for you
.So, we should avoid it by
 Using BHT free polythine .
 Maintaining PH 6 or below 6 .
 Make free your production area from oxides of nitrogen .
 Using finishing chemical free from phenolic compound
 Using non ionic or anti-ozone softener .

3. Epyllion Testing lab Ltd Your Partner in Textile Testing
Md. Shafiqul ISLAM (Newton)
Manager –Softlines lab, Epyllion Testing Lab Ltd,
Gazipur, Dhaka, Bangladesh
Email: newton@epylliongroup.com
Cell: +8801713423577