GB/T 38408-2019 English PDF (GBT38408-2019)

This Standard specifies the method of microscopy for the identification of leather. This Standard is applicable to the identification of various types of leather and its products; leather fiber board may take this as a reference.

GB/T 38408-2019
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 59.140.30
Y 46
Leather - Identification - Method of Microscopy
ISSUED ON: DECEMBER 31, 2019
IMPLEMENTED ON: JULY 1, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 4
4 Principle ... 5
5 Equipment and Materials ... 5
6 Sampling and Specimen Preparation ... 6
7 Identification Process ... 6
8 Result Identification and Expression ... 7
9 Test Report ... 7
Appendix A (informative) Surface and Longitudinal-section Structure of
Commonly-seen Animal Leather ... 8
Appendix B (informative) Longitudinal-section Structure Form of Three
Synthetic Materials ... 15
Leather - Identification - Method of Microscopy
1 Scope
This Standard specifies the method of microscopy for the identification of leather. This Standard is applicable to the identification of various types of leather and its products; leather fiber board may take this as a reference.
2 Normative References
The following documents are indispensable to the application of this document. In terms of references with a specified date, only versions with a specified date are applicable to this document. In terms of references without a specified date, the latest version (including all the modifications) is applicable to this document. GB/T 22889 Leather - Physical and Mechanical Tests - Determination of Surface Coating Thickness
QB/T 2262 Terms of Leather Industry
3 Terms and Definitions
The following terms and definitions are applicable to this document.
3.1 Leather
Leather refers to a raw hide with a roughly complete natural fiber structure, which is made into a non-perishable material through tanning.
NOTE 1: Definition 4.1 of QB/T 2622-1996 is rewritten.
NOTE 2: the hair on the skin has generally been removed, but it may be intentionally retained.
NOTE 3: leather may be made from a raw hide or skin slice that is split into several layers. The splitting may be carried out before or after tanning.
NOTE 4: the used surface of the leather may or may not have surface modification, such as: coating and transfer film, etc.
3.2 Grain
pictures. If there is a standard sample, the standard sample shall prevail in use. 6 Sampling and Specimen Preparation
6.1 Sampling Location
Specimens shall be cut at locations with obvious structural characteristics of animal tissues.
6.2 Specimen Preparation
Cut 3 specimens of an appropriate size.
Specimen A: used to observe the surface. If necessary, acetone, ethanol or an appropriate solvent may be used to remove the coating on the surface of the specimen; Specimen B: used to observe the structure of the longitudinal-section tissue. During the cutting process, it shall be ensured that the cutting edge of the blade is perpendicular to the surface of the specimen;
Specimen C (if necessary): used to determine the thickness of the coating. 7 Identification Process
Place Specimen A flatwise, with the surface facing upward, under the microscope, so as to observe its surface. Place Specimen B flatwise, with the longitudinal-section facing upward, under the microscope, so as to observe the structure of the longitudinal- section tissue. In combination of the characteristics of the surface and the longitudinal section, conduct comparative identification analysis with the reference samples or pictures (see Appendix A), so as to confirm the texture of the leather. NOTE 1: during the identification, pay attention to the differences between the longitudinal- section structure of the leather, and leather fiber board and commonly-seen synthetic materials (see Appendix B).
NOTE 2: the pore arrangement of the leather grain is the most important characteristic information of identifying the type of leather.
For specimens with a relatively thick coating or transfer film layer, in accordance with the stipulations of GB/T 22889, the thickness of the coating or the transfer film layer of Specimen C, and its percentage of the total thickness may also be determined; in accordance with the requirements of 8.2, issue the identification results.