GB/T 3671.2-2025Determination of cold water solubility of water-soluble dyes (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 Part 2 of GB/T 3671.GB/T 3671 has already published the following parts.

---GB/T 3671.1 Determination of solubility and solution stability of water-soluble dyes;

---GB/T 3671.2 Determination of cold water solubility of water-soluble dyes.

This document replaces GB/T 3671.2-1996 "Determination of cold water solubility of water-soluble dyes". Compared with GB/T 3671.2-1996, except for...

Aside from structural adjustments and editorial changes, the main technical changes are as follows.

a) Added terms and definitions (see Chapter 3);

b) The requirements for beakers have been changed (see 5.1, 4.1 of the 1996 edition);

c) The filter paper content has been changed (see 5.7, 4.7 of the 1996 edition);

d) The vacuum level adjustment settings have been modified (see 7.4, 6.3 of the 1996 version);

e) The filtering operation has been modified (see 7.5, 6.4 and 6.5 of the 1996 version).

This document is modified to adopt ISO 105-Z09.1995 "Textiles, tests for color fastness Z09 – Part II. Solubility of water-soluble dyes in cold water".

Measurement.

Compared with ISO 105-Z09.1995, this document has undergone many structural adjustments. A comparison of the structural numbering changes between the two documents is provided below.

See Appendix A for the table of contents.

This document differs significantly from ISO 105-Z09.1995.The relevant clauses are indicated in vertical margins.

The straight lines (|) are marked. A summary of these technical differences and their reasons can be found in Appendix B.

The following editorial changes have been made to this document.

---To align with existing standards, the standard name has been changed to "Determination of the cold water solubility of water-soluble dyes".

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 Petroleum and Chemical Industry Federation.

This document is under the jurisdiction of the National Technical Committee on Standardization of Dyes (SAC/TC134).

Introduction

Water-soluble dyes are classified according to their application properties into direct dyes, acid dyes, cationic dyes, reactive dyes, condensation dyes, and reactive fluorescent dyes.

For example, the solubility of water-soluble dyes is closely related to their application performance, and solubility is one of the important technical indicators of water-soluble dyes.

GB/T 3671 aims to provide a basis for the determination of the solubility of water-soluble dyes and is proposed to consist of two parts.

---GB/T 3671.1 Determination of solubility and solution stability of water-soluble dyes;

---GB/T 3671.2 Determination of cold water solubility of water-soluble dyes.

Determination of the cold water solubility of water-soluble dyes

1 Scope

This document describes a method for determining the solubility of water-soluble dyes in unheated aqueous solutions at 25°C.

This document applies to the determination of the cold water solubility of water-soluble dyes. It is not applicable to the measurement of absolute solubility.

Note. Appendix C lists several factors that may affect the test results.

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 1914 Chemical Analysis Filter Paper GB/T 6682-2008 Specifications and test methods for water used in analytical laboratories (ISO 3696:1987, MOD) Note. There are no technical differences between the content referenced in GB/T 6682-2008 and the content referenced in ISO 3696:1987.

GB/T 15724 Laboratory glassware beakers (GB/T 15724-2024, ISO 3819:2015, MOD)

3 Terms and Definitions

The following terms and definitions apply to this document.

cold water solubility the limit concentration at which a dye can be completely dissolved in water at 25°C.

Note. The unit is grams per liter (g/L).

4 Principles

Solutions of several known concentrations, including the solubility limit of the dye to be tested, were prepared at 25°C. The solutions were then subjected to an oxidation reaction at this temperature.

The solution was filtered through a heated vacuum filter, and the cold water dissolution was determined by visual evaluation of the filter residue and measurement of the filtrate flow time.

Degree limit.

5 Equipment and Reagents