GB/T 2378-2025 Acid dyes—Determination of shade and relative strength English, Anglais, Englisch, Inglés, えいご
This is a draft translation for reference among interesting stakeholders. The finalized translation (passing thorugh draft translation, self-check, revision and varification) will be delivered upon being ordered.
ICS 71.100.01;87.060.10 CCS G55
NATIONAL STANDARD OF THE PEOPLE'S REPUBLIC OF CHINA
GB/T 2378-2025
Replace GB/T 2378-2012, GB/T 33421-2016
Determination of Shade and Strength for Acid Dyes
Issued on 2025-08-29 Implemented on 2026-03-01
Issued by State Administration for Market Regulation
Standardization Administration of China
Contents
1 Scope
2 Normative References
3 Terms and Definitions
4 Principles
5 Reagents and Materials
6 Instruments and Equipment
7 Test Methods
Determination of Shade and Strength for Acid Dyes
1 Scope
This document describes methods for determining shade and strength of acid dyes using dyeing method and solution colorimetric method.
The dyeing method is applicable to acid dyes used for textile dyeing, while the solution colorimetric method is suitable for acid dyes with high purity or those used in daily chemical products.
2 Normative References
The following documents' contents are indispensable clauses through normative references in this document. For dated references, only the edition corresponding to the date applies; for undated references, the latest edition (including all amendments) applies.
GB/T 2374-2017 Dyes - General conditions for dyeing tests
GB/T 6687 Terminology of dyes
3 Terms and Definitions
The terms and definitions defined in GB/T 6687 apply to this document.
4 Principles
4.1 Dyeing Method
The acid dye sample and the standard sample of the same variety are dyed under the same conditions on appropriate fibers (wool, nylon). The dyeing strength of the standard sample is taken as 100 points, and the shade is used as the standard for visual comparison to evaluate the shade and strength of the sample. Alternatively, a colorimeter may be used for color measurement, and then the shade and strength of the sample are calculated.
4.2 Solution Colorimetric Method
When the dye solution complies with the Lambert-Beer law, the acid dye sample and standard sample are diluted with water to a fixed volume, and their absorbance values at the maximum absorption wavelength are measured separately using a spectrophotometer to calculate the strength of the dye sample. When the absorbance values are basically the same, the color difference between the standard sample and sample can be visually compared in a colorimetric tube to evaluate the shade of the sample.
5 Reagents and Materials
Reagents and materials shall comply with the provisions of Chapter 3 in GB/T 2374-2017.
6 Instruments and Equipment
Instruments and equipment shall comply with the provisions of Chapter 4 in GB/T 2374-2017.
