Testing Greying vs. Whiteness Maintenance


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You can find some remarks regarding Whiteness Tracers further down on this page.

Ballast soil for redeposition tests

Background

"Soil makes a difference!" What is true for stain removal testing is even more true for assessing soil redeposition or rather: whiteness maintenance performance. Existing ballast soil systems with total soil quantities as for single wash tests may be used for such testing, but appear to require too many wash cycles to obtain significant results. An ideal redeposition test system replicates 'real' greying levels with less wash cycles: "Accellerate - don't exaggerate!"

There is currently no commonly agreed test protocol for assessing whiteness maintenance... except the  A.I.S.E. minimum test protocol which specifies the use of SBL2004 as soil ballast, dosed as for stain removal testing. However, the common experience (at least to our knowledge) is that the resulting soil level in the wash liquor is not sufficient for accellerated greying tests, the approach therefore of very limited suitability.

The following list gives an overview of products and approaches that we know are currently used. Absolute redeposition levels may vary depending on the type of soil donor. The complexity of the soil composition increases from GS-1 to GS-2 and then again to SBL2004. We expect GS-1 to 'cause' the highest levels of redeposition and SBL2004 (if dosed as mentioned below) to achieve the most balanced (but still measurable) results. To some extent GS-2 is a combination of both approaches.

Products

wfk GREYING SWATCH I
  • 100 % cotton terry cloth swatch.

Soil consisting of fats, pigments, starch, proteine.
Contains silicone oil as suds surpressor
Application (full scale tests in washing machines):
- Use clean ballast loads.
- Use 1 wfk GREYING SWATCH as soil donor per 3,5 kg ballast load.
- Use white test specimen (adjacent fabrics) as soil acceptors.
- Run 5 to 10 replicates, without exchanging the load and test specimen but replacing the wfk GREYING SWATCH with a new one for each replicate.
- Evaluate the redeposition on the white test specimen e.g. by reflectance measurement.

Any resulting redeposition is achieved with a limited number of test runs, its maximum level will not substantially exceed 'real' greying levels as experience by consumers.

 
wfk GREYING SWATCH II
  • 100 % cotton terry cloth swatch.

Soil consisting of fats, pigments, starch, proteine and additionally components as in SBL2004. No silicone.
Application (full scale tests in washing machines):
- Use clean ballast loads.
- Use 1 wfk GREYING SWATCH as soil donor per 3,5 kg ballast load.
- Use white test specimen (adjacent fabrics) as soil acceptors.
- Run 5 to 10 replicates, without exchanging the load and test specimen but replacing the wfk GREYING SWATCH with a new one for each replicate.
- Evaluate the redeposition on the white test specimen e.g. by reflectance measurement.

Any resulting redeposition is achieved with a limited number of test runs, its maximum level is slightly lower than that obtained with Greying Swatch I and will as well not substantially exceed 'real' greying levels as experience by consumers.

 
wfk SBL2004
  • 100 % cotton plain weave swatch.

Soil consisting of a complex mixture of natural and synthetic oils and fats, pigments, starch, proteine, salts ....
Application (full scale tests in washing machines):
- Use clean ballast loads.
- Use 2 wfk SBL2004 sheets as soil donor per kg ballast load.
- Use white test specimen (adjacent fabrics) as soil acceptors.
- Run 6 to 10 replicates, without exchanging the load and test specimen but replacing the wfk SBL2004 with new sheets for each replicate.
- Evaluate the redeposition on the white test specimen e.g. by reflectance measurement.

The application of SBL2004 introduces a very balanced level of soil ballast of complex composition. Any redeposition can be expected to show after a limited number of test runs and not to exceed 'real' greying levels as experience by consumers.

SBL2004 is the only product in this category that allows to easily adjust the 'dosage' depending on actual load size - even to very small systems, e.g. Launder-Ometer, Terg-O-Tometer, Linitest ...

 

 

Whiteness Tracers

Background

While Ballast soil is required to mimic redeposition, white fabrics are the tracers that are used to reflect and measure the effect. White test fabrics are available in some variety from dfferent sources.

The A.I.S.E. minimum test protocol specifies the use cotton, polycotton, polyester and nylon - which represents a common testing approach. However, we feel that 'modern' types of fabrics are very little represented so far but may add additional challenges to whiteness maintenance in practice.

We are currently exploring options and work on identifying relevant new fabric types. This was actually the main content of a presentaion given at the 2015 IDC conference in Duesseldorf which you can find in our presentations section.

Please contact us if wish to receive updates about this project.