Explain the key differences between the ASTM D2054 and EN ISO 11640 standards for testing the color fastness of leather against rubbing.
1. Test Method: The ASTM D2054 standard uses a rubbing test method that involves rubbing the leather sample against a white cotton cloth using a specified load and number of rubs. The EN ISO 11640 standard also uses a rubbing method, but the procedure involves rubbing the leather sample against a specified rubbing head using a specified number of cycles.
2. Evaluation Criteria: The evaluation criteria for the two standards are slightly different. ASTM D2054 evaluates the colorfastness of leather to both dry and wet rubbing, while the EN ISO 11640 standard only evaluates the colorfastness to dry rubbing. The evaluation criteria for color transfer, appearance change, and color change are also slightly different between the two standards.
3. Rating Scale: The rating scales used in the two standards are different. ASTM D2054 uses a rating scale of 1 to 5, with 5 indicating severe color transfer, while EN ISO 11640 uses a rating scale of 1 to 5, with 5 indicating no color transfer. Additionally, the rating scales for appearance change and color change are different between the two standards.
4. Requirements: The two standards have different requirements for the equipment used in the test. For example, ASTM D2054 specifies the use of a crockmeter for the rubbing test, while EN ISO 11640 specifies the use of a rubbing head. The standards also have different requirements for the size and preparation of the leather sample.
Overall, while both ASTM D2054 and EN ISO 11640 are used for testing the color fastness of leather against rubbing, they have some key differences in terms of the test method, evaluation criteria, rating scale, and requirements. It is important to choose the appropriate standard based on the intended use of the leather product and the requirements of the industry or regulatory body.