GB/T 40920-2021 in English

Interpretation of the core content of the standard

This standard specifies the method for evaluating the friction resistance of leather surfaces using the friction color fastness tester. The main technical features include:

Key technical points

1. Sample preparation specifications

The sample size should be ≥100×20mm. The wet sample is prepared by the vacuum impregnation method (5kPa vacuum degree). Boiling of black felt is prohibited to avoid fading.

2. Test process control

Note:

• The specimen needs to be pre-stretched by 10% (special circumstances need to be recorded)
• After wet testing, it needs to be dried at room temperature before rating
• Coated leather needs to be treated with non-pigmented shoe polish

Differences from international standards

Implementation suggestions

Special attention should be paid during laboratory operations:

• Select corresponding test pressures for different leather types
• Felt processing strictly distinguishes between dry and wet methods
• Rating uses D65 standard light source
• Disputed situations require sampling and testing of multiple parts