ISO 21490:2022 ゴムおよびゴム製品—高速液体クロマトグラフィー（HPLC）による2-メルカプトベンゾチアゾール含有量の測定 | ページ 2

Foreword

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This document was prepared by ISO/TC 45, Rubber and rubber products, Subcommittee SC 2, Testing and analysis.

Introduction

2-Mercaptobenzothiazole (sometimes also referred to as: MBT; 2-MBT; 2-benzothiazolethione, or BTSH) is used in the rubber industry as a curing agent. MBT is in the group of thiazoles and is considered as scorch fast when used as a primary accelerator.

2-Mercaptobenzothiazole as the acidic sulfur accelerator is widely used in rubber materials because of its good characteristics: stable sulfides, good vulcanization, and a low critical temperature to accelerate vulcanization so that the rubber product can reach higher tensile strength and hardness levels.

Measuring 2-mercaptobenzothiazole concentration in rubber compounds at different stages of curing the rubber product is an excellent means to define the optimal curing conditions of temperature and time in order to obtain the right properties for the products at the best cost.

During the curing of rubber compounds sulfenamides are used as accelerators, which chemically react at an early stage of the curing to produce 2-mercaptobenzothiazole and other species. 2-Mercaptobenzothiazole then contributes to the initiation of the mechanism which creates the sulfur crosslinks between the rubber macromolecules at the end (an example is given in Figure A.1). To ensure continuous progress, it is important to know the chemical mechanisms involved at each stage. Thus, it is necessary to quantify the content of 2-mercaptobenzothiazole during the decomposition of the sulfenamide and to know whether 2-mercaptobenzothiazole has disappeared in any further chemical reactions.

1 Scope

This document specifies a quantitative test method to determine the 2-mercaptobenzothiazole content in rubber and rubber products by high performance liquid chromatography (HPLC).

This document delivers a method for quantifying 2-mercaptobenzothiazole in rubber products for a better selection of curing conditions.

This document provides a method to follow the curing of rubber with sulfur- and benzothiazole-based accelerators using a chemical measurement which is complementary to the classical rheometric technique.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

3 Terms and definitions

No terms and definitions are listed in this document.

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Bibliography