GB/T 42950-2023Leather - Tests for colour fastness - Colour fastness to saliva (English PDF)

Foreword

This document was issued on 6 August 2023 by the State Administration for Market Regulation; Standardization Administration of the PRC and takes effect on 1 March 2024.

It is a GB/T standard: recommended rather than compulsory, but it is the text a Chinese reviewer applies when assessing a submission.

1 Scope

GB/T 42950-2023 covers the test for colour fastness to saliva on leather of any type — the principle, the apparatus and materials, the reagents, the sampling and preparation of specimens, the test steps, the evaluation of the result, the assessment error allowed, and the report. Leather reaches the mouth more often than a tannery imagines: children chew straps, handles and toys, and a dye that does not stay in the leather when it is wetted with saliva is a dye that leaves the leather. The method holds filter paper soaked in artificial saliva in close contact with the specimen; strips of qualitative filter paper of about 80 mm by 15 mm are soaked until they are completely moistened before being applied. Once the paper strip and the specimen have dried, the staining of the paper and the change in colour of the leather are graded against the grey scale for assessing staining and the grey scale for assessing change in colour. Because that grading is done by eye, the difference between two testers is capped at half a grade, which is what stops two laboratories reporting different verdicts on the same hide. Written for tanneries, leather goods makers, and the laboratories testing to their specifications.

This document describes a test method for the colour fastness to saliva of leather.

This document is applicable to the determination of colour fastness to saliva of various

types of leather.

2 Normative references

The following documents contain the provisions which, through normative reference in

this document, constitute the essential provisions of this document. For the dated

referenced documents, only the versions with the indicated dates are applicable to this

document; for the undated referenced documents, only the latest versions (including all

the amendments) are applicable to this document.

GB/T 250 Textiles - Tests for colour fastness - Grey scale for assessing change in

colour (GB/T 250-2008, ISO 105-A02:1993, IDT)

GB/T 251 Textiles - Tests for colour fastness - Grey scale for assessing staining

(GB/T 251-2008, ISO 105-A03:1993, IDT)

GB/T 6151 Textiles - Tests for colour fastness - General principles of testing (GB/T

6151-2016, ISO 105-A01:2010, MOD)

GB/T 6682 Water for analytical laboratory use - Specification and test methods

(GB/T 6682-2008, ISO 3696:1987, MOD)

GB/T 39364 Leather - Chemical, physical, mechanical and fastness tests -

Sampling location (GB/T 39364-2020, ISO 2418:2017, MOD)

QB/T 2262 Terms of Lether Industry

3 Terms and definitions

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

4 Principle

The filter paper soaked in artificial saliva is closely attached to the leather specimen to