GB/T 38406-2019Leather chemicals - Determination of tannin content in synthetic tanning agents (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This standard uses the redrafting method to modify the use of ISO 17489..2013

set".

Compared with ISO 17489..2013, this standard has more adjustments in structure.Appendix A gives the standard and ISO 17489..2013.

List of chapter number comparisons.

Compared with ISO 17489..2013, the following technical modifications have been made to this standard to adapt to China's actual situation.

--- Regarding the normative references, this standard has made adjustments with technical differences. The adjustments are reflected in Chapter 2

In the "general reference documents", the specific adjustments are as follows.

* ISO 3696. 1987 was replaced by GB/T 6682, which adopted the international standard;

--- Modified the description in "4 Principles", more in line with China's habits;

--- "6 Instruments and Equipment" adjusted the beaker volume requirements and added a "centrifuge";

--- Adjusted the description method of "7.1 Preparation of synthetic tanning agent solution for analysis";

--- 7.1 gives the temperature range of warm water for easy operation and use;

--- 7.2 The water bath heating is modified to a low temperature oven to improve the accuracy of the results.

The following editorial changes have been made to this standard.

--- Modify the standard name to "Determination of Tannin Content in Leather Chemical Synthetic Tanning Agents" to comply with China's leather standardization system;

--- Removed the example of the type of desiccant in "6.6 Dryer";

--- Deleted informative appendix A and informative appendix B;

--- Removed references.

This standard is proposed by the China Light Industry Federation.

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

This standard was drafted. Zhejiang Shenghui Chemical Co., Ltd., Huizhou Quality Measurement Supervision and Inspection Institute of Guangdong Province, Zhejiang Jinyuan Industry Co., Ltd.

Company, Guangdong Xinhuwei Industrial Investment Co., Ltd., Jinjiang Anhai Hengtai Leather Co., Ltd., China Leather Shoes Research Institute Co., Ltd.

1 Scope

This standard specifies the determination of tannin content in synthetic tanning agents.

This standard applies to the determination of tannin content in various tanning synthetic tanning agents.

2 Normative references

The following documents are essential for the application of this document. For dated references, only the dated version applies to this article

Pieces. For undated references, the latest version (including all amendments) applies to this document.

GB/T 6682 Analytical laboratory water specifications and test methods (GB/T 6682-2008, ISO 3696. 1987, MOD)

3 terms and definitions

The following terms and definitions apply to this document.

3.1

Tannin content

Synthetic tanning agent when mixed with a crosslinked, insoluble vinylimidazole/vinylpyrrolidone copolymer product in an aqueous solution

The content of adsorbable components in the agent.

4 Principle

At room temperature, the acidified synthetic tanning agent solution is mixed with the insoluble copolymer. The copolymer can adsorb the polyphenol in the tanning agent and pass the test.

The difference between the dry matter content of the solution before and after the synthetic tanning agent and the adsorption copolymer is the content of the adsorbable component.

5 Reagents and materials

5.1 General requirements. Unless otherwise specified, the reagents used are analytical grade, and the test water should meet the requirements of Grade III water in GB/T 6682.

6 Instruments and equipment