Abrasion Testing: Key Terms and Standards

ASTM D4060 and ASTM D2486 are both abrasion test methods for paint and coatings, but they measure different types of abrasion and are used for different applications. 

ASTM D4060 (Taber Abrasion) uses a rotating-platform instrument fitted with abrasive wheels that wear down a coated panel under a specified load. Results are expressed as mass loss in milligrams after a defined number of cycles – typically 500 or 1,000. It is widely used for metal coatings, industrial finishes, and floor coatings. 

ASTM D2486 (Scrub Resistance) is a wet abrasion test that measures how many scrub strokes a wall paint can withstand before showing film failure. A brush loaded with a water-based abrasive compound is passed back and forth over a panel under controlled conditions. It is the primary standard for evaluating the durability of architectural interior paints. 

The choice of standard depends on the coating type, substrate, and end-use environment. TQC Sheen instruments from Industrial Physics are designed to support both methods – visit industrialphysics.com for more information on our paint and coatings testing range. 

ISO 11998 is an international standard that assesses the wet scrub resistance and cleanability of architectural coatings – particularly interior wall paints. It is the basis for EN 13300, which classifies paints into scrub resistance classes from Class 1 (highly resistant) to Class 5 (limited resistance).

In an ISO 11998 test, the coating is applied to a standardized substrate at a defined film thickness and allowed to cure. The panel is then subjected to 200 scrub cycles using a standardized abrasive pad and a defined test solution. After testing, the change in dry film thickness is measured using a profilometer or film thickness gauge.

The result – expressed as micrometers of film lost per scrub cycle – determines the classification of the coating. This classification is used in product labeling, technical data sheets, and regulatory compliance for products sold in the EU market under EN 13300.

Accurate film thickness measurement before and after testing is critical to generating valid ISO 11998 results. Industrial Physics offers film thickness measurement instruments through the TQC Sheen range, as well as scrub testing equipment designed to meet the requirements of this standard.

Several variables can influence the outcome of an abrasion test. Understanding and controlling these factors is essential for generating reliable, repeatable results. 

Dry film thickness (DFT): Thicker films generally show lower mass loss and more cycles to failure. DFT must be measured and recorded before testing to allow meaningful comparison between samples. 

Cure conditions: A coating that has not fully cured will underperform in abrasion testing. Test panels must be allowed to cure under controlled conditions (temperature and humidity) for the time specified in the standard or the product data sheet. 

Abrasive wheel or brush condition: Taber abrasive wheels must be conditioned by running them on a calibration panel before use, as specified in ASTM D4060. Worn or contaminated wheels will generate inconsistent results. 

Substrate preparation: Surface roughness and substrate type affect adhesion and, therefore, abrasion performance. Always use the substrate specified in the applicable standard. 

Environmental conditions: Temperature and relative humidity affect the properties of water-based coatings during both curing and testing. Conditioning test panels in a controlled environment is best practice.