Evaluating Stain Removal Performance in Home Laundering

By: Katherine Hatherley, LABORATORY TECHNICAL SPECIALIST, email

You may have seen a laundry detergent commercial where two identical shirts are splashed with mud, wine, or rubbed with grass stain. This is usually followed by a comparison of what each shirt looks like after a certain product’s cleaning versus its competitor, right? But what really goes on in laboratory testing of stain removal products? Are lab technicians throwing mud at shirts? A lot of work goes into creating a laundry detergent, from the choice of various surfactants and surface active ingredients, to the detergent testing of the completed product.

In this article, we’ll review one of the standard methods recognized worldwide to measure the stain removal efficiency of a home laundering product, ASTM D4265 – Evaluating Stain Removal Performance in Home Laundering. Dell Tech is one of the leading detergent testing laboratories in North America and we perform this method regularly for our clients.

Products We Test

This method is used to test the following household cleaners, including:

• liquid laundry detergent
• powder laundry detergent
• synthetic detergents
• laundry soda
• laundry soap
• washing powder
• stain remover
• pre-wash treatment

Why this Test

ASTM D4265 is used to determine a product’s cleaning efficiency by its ability to remove standard stains.

Results

The results may be used for claims substantiation and cleaning efficiency compared to other products tested with the same standard under the same test conditions.

What is ASTM D4265 and How Does it Work?

ASTM D4265 is a full-scale evaluation of performance with household washers and dryers, closely correlating to the consumer experience. The method prescribes the types of washing machines and drying equipment that may be used. Fabric stains are artificially applied to specified fabric types and allowed to set for the prescribed amount of time. After this period, these stain swatches are washed with the products being compared and the relative degree of removal of the stains is evaluated.

What types of stains are used?

This is not an exhaustive list, but some typical stains include:

• Peat
• Animal fat/red dye
• Motor oil
• Red wine
• Dessert (chocolate)
• Grass
• Butter
• Curry
• Blood
• Beta-carotene
• Clay
• Make-up
• Tomato sauce
• Tea
• Baby food

How is the degree of stain removal evaluated in detergent testing?

Averaged reflectance measurements of the fabric are taken using a colorimeter before the cloth is stained, after it is stained, and again after being treated with the product and washed. The performance of the product is evaluated instrumentally by a Stain Removal Index (SRI). The SRI is a scale from 0-100, with 0 meaning no stain removal, and 100 meaning complete stain removal. The SRI is calculated as:

SRI  = 100 x ΔE*_(US-UF) – ΔE*_(WS-UF)

ΔE*_(US-UF)

Where:

US = Unwashed stain area

UF = Unwashed (unstained) fabric area

ΔE*(US-UF) = Delta-E color difference between the unwashed stain and the unwashed fabric

Δ E*(WS-UF) = Delta-E color difference between the washed stain and the unwashed fabric.

The value ΔE (absolute color difference) is calculated as:

ΔE*  = √ΔL*²+ Δa*²+ Δb*²

Where:

L = reflectance

a = redness/greenness

b = yellowness/blueness

ASTM D4265 is an excellent test for comparing products’ stain removal ability under the same conditions, useful for “formulation studies, quality control, and ingredient raw materials qualification”. However, the method notes that “there is no single combination of stain and fabric that will predict the overall performance of a product or treatment method”. Different conditions in the consumer home will deliver different results.

Current regulations do not require that detergent testing be performed on household cleaners like synthetic detergents, but detergent testing may be needed for standard certification by a third party eco certification body like Green Seal, Safer Choice, or UL Ecologo.

Other Laundry Tests at Dell Tech

Here is a list of the other detergent tests we can assist you with in our lab:

• ASTM D4265 – Stain pretreatment or laundry boosters
• ASTM D4265 – Color Fastness
• ASTM D4265 – Foaming Test for HE logo validation
• ASTM D5548 – Standard Guide for Evaluating Color Transfer or Color Loss of Dyed Fabrics in Laundering
• AATCC TM 135 Dimensional Changes of Fabrics after Home Laundering

Email Kate if you have a laundry product you would like tested, or specific questions about this method. Go to our Chemical Lab Testing Services main page to learn more about other testing services offered at Dell Tech.

Dell Tech has provided professional, confidential consulting services to the specialty chemical 

industry in Canada, the USA, Europe, and Asia for the last 40 years.