Background information

work instruction ILM

A high total wear during the washing process is often not noticed or noticed too late. High total wear increases costs because laundry is worn-out quicker and therefore has to be replaced sooner. To be able to check the total wear which appears during the washing process, the wear must be measured. For this purpose the Industrial Laundry Monitor (ILM) can be used. Besides determination of total wear (a combination of mechanical and chemical wear), the chemical wear, ash content and whiteness in artificial light and whiteness in daylight can be determined.

 

The monitor consists of a (white) standardized cotton cloth. The cloth is divided into strips by in woven green threads. This division is necessary for the various analyses.

Performing the test is very easy. The monitor has to be washed 25 times (optionally 50 times) with the washing process to be tested. Each cycle must take place with the same process and same type of laundry. The cloth must be washed without ironing or drying in between. If desired the cloth can be air-dried in between two cycles. The number of cycles can be registered on the enclosed form. After the last cycle the cloth has to be dried. After drying the cloth can be returned and then we will perform the agreed analyses.

 

• total wear (loss of tensile strength)
• chemical wear (factor of damage)
• ash content
• whiteness in artificial light
• whiteness in daylight
  
   

Total wear

The total wear is determined by measuring the loss of tensile strength. This is a combination of the mechanical as well as the chemical wear.

Chemical wear
The chemical wear is determined by establishing the average chain length of the cellulose, the degree of polymerisation. The result is expressed in the damaging factor, which is linear with the chemical wear.

Chemical wear is caused mainly by unfavourable bleaching circumstances. These can be caused by, for example, a too high concentration of bleaching agent, wrong pH value, wrong temperature, iron present in the water etc.

Ash content
The ash content is determined by ashing the cotton. The ashes, which remain, will be weighed and calculated on weight bases.

When hard water is used for washing, or when rinsing is insufficient, the ash content will increase. If high ash content is found, the cause might be e.g. problems with the water softener, insufficient rinsing etc.

Whiteness in artificial light
This parameter gives an impression of the whiteness in artificial light, without ultraviolet.

When the whiteness is too low, this can be caused by greying. This greying can occur when rinsing is not done sufficiently or when the detergent concentration is too low.

Whiteness in daylight
Besides whiteness in artificial light, the ultraviolet (UV) component is determined too.

The optic brighteners present in detergents turn UV-light into visible light. In daylight this gives an 'extra' white impression. This effect is measured.