GB/T 47791-2026Leather - Physical and mechanical tests - Determination of resistance to grain cracking and grain crack index (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents".

Drafting.

This document is modified to adopt ISO 3378:2002 "Leather - Physical and mechanical tests - Determination of grain strength and folding index".

This document has undergone the following structural adjustments compared to ISO 3378:2002.

---Added "3 Terms and Definitions", with subsequent chapter numbers following accordingly;

--- Combine sections 4.2 to 4.5 into 5.1, and then number the subsequent chapters and sections sequentially.

---6.1 corresponds to the first sentence of section 5.1 in ISO 3378:2002;

---6.2 corresponds to the second sentence and note in section 5.1 of ISO 3378:2002.

---Added terms and definitions, as well as normative references to QB/T 2262 (see Chapter 3), to facilitate the understanding and use of the standard;

---Regarding the specifications for adjusting the die cutter and specimen, the normative reference QB/T 2707 replaces ISO 2419 (see 5.2 and).

6.3), to conform to my country's technical conditions and facilitate use;

---Regarding the regulations for thickness gauges and thickness measurement, the normatively referenced GB/T 45705 replaces ISO 2589 (see 5.3 and).

6.4) to conform to my country's technical conditions and facilitate use;

---Regarding the sampling requirements for standard locations, ISO 2418 (see 6.1) has been replaced with the normatively referenced GB/T 39364 to comply with...

Our country's technological conditions are conducive to its use;

---Regulations for sampling of non-standard areas have been added (see 6.1) to meet the needs of routine testing;

---Added sampling for cases where the direction of the spine line cannot be identified (see 6.2) to meet the needs of routine testing;

---Regulations for taking test results have been added (see Chapter 8) to standardize the operations of various institutions.

The following editorial changes have been made to this document.

---A new heading, "Sampling and Sample Preparation," has been added;

---Added explanatory notes on mandrel selection during testing;

---Informative Appendix B, "Equipment Source," has been deleted.

Please note that some content in this document may involve patents. The issuing organization of this document assumes no responsibility for identifying patents.

This document was proposed by the China National Light Industry Council.

This document is under the jurisdiction of the National Technical Committee on Standardization of Leather Industry (SAC/TC252).

1 Scope

This document describes the test methods for determining the crack resistance and tear index of leather grain.

This document applies to the determination of the crack resistance and tear index of leather grain.

2 Normative references

The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included.

For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies.

This document.

GB/T 39364 Sampling sites for testing the chemical, physical, mechanical and color fastness of leather (GB/T 39364-2020, ISO 2418.

2017, MOD)

GB/T 45705 Physical and mechanical tests of leather - Determination of thickness (GB/T 45705-2025, ISO 2589:2016, MOD) QB/T 2262 Leather Industry Terminology QB/T 2707 Preparation and conditioning of test specimens for physical and mechanical testing of leather

3 Terms and Definitions

The terms and definitions defined in QB/T 2262 apply to this document.

4 Principles

Examine the leather grain and record any cracks or creases.

5 Instruments and Equipment