Measuring Durometer Hardness Scales
The Standard testing method for rubber properties is a durometer hardness test. According to the ASTM International website, https://www.astm.org/Standards/D2240.htm, “This test method is based on the penetration of a specific type of indentor when forced into the material under specified conditions. The indentation hardness is inversely related to the penetration and is dependent on the elastic modulus and viscoelastic behavior of the material”. While there are twelve different scales recognized by the ASTM standard, only three of them are typically seen in the roller industry.
Developed in 1920 by Albert Ferdinand Shore, the Shore Durometer is a device that determines the hardness of various materials. While the terms Durometer and Hardness are used interchangeably, the term Durometer is the international standard used for measurement of rubber hardness in various industries such as printing, laminating, coating, and converting, and it also refers to the instrument itself. American Roller adheres to the ASTM International standard test method ASTM D2240, and classifies compounds according to the three common durometer scales.
The three scales commonly seen in the roller industry are “OO”, “Shore A”, and “Shore D”. Each scale ranges from 1-100.
- OO Scale: This scale is found used on most foam coverings and extremely soft materials.
- Example: Sponge & Foam Rollers (15-30 Shore OO)
- Shore A: The most widely used scale of the three in the roller industry and encompasses most of American Roller rubber and urethane coverings.
- Example: Extrusion Nip Rollers (60-80 Shore A)
- Shore D: Used on extremely hard materials.
- Example: Paper Mill Rollers (80 Shore D)
When you need your roller covered with a rubber or urethane compound, let our dedicated in-house research and development team, which includes our on-staff Ph.D. Chemist, assist in selecting an appropriate compound or formulate a new one if necessary.
Contact us to discuss your formulary needs and leave a message for our on-staff Ph.D. Chemist today: