ISO 48-8:2018 ゴム、加硫または熱可塑性プラスチック—硬度の決定—パート8：Pusey andJones法によるゴムで覆われたローラーの見かけの硬度 | ページ 2

Foreword

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The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives ).

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

This first edition of ISO 48-8 cancels and replaces ISO 7267-3:2017, of which it constitutes a minor revision. The changes compared to the previous edition are as follows:

• a new standard number has been given.
• the Introduction, an explanation of the purpose of the grouping work has been added.

A list of all parts in the ISO 48 series can be found on the ISO website.

Introduction

ISO/TC 45/SC 2 established a principle that it would be helpful for users if standards on the same subject but covering different aspects or methods were grouped together, preferably with an introductory guidance standard, rather than being scattered throughout the numbering system. This has been achieved for some subjects, for example curemeters (ISO 6502) and dynamic properties (ISO 4664).

In 2017, it was decided to group standards for hardness and, subsequently, it was agreed that they would be grouped under the ISO 48 number. The new standards together with the previously numbered standards are listed below.

• ISO 48-1: former ISO 18517
• ISO 48-2: former ISO 48
• ISO 48-3: former ISO 27588
• ISO 48-4: former ISO 7619-1
• ISO 48-5: former ISO 7619-2
• ISO 48-6: former ISO 7267-1
• ISO 48-7: former ISO 7267-2
• ISO 48-8: former ISO 7267-3
• ISO 48-9: former ISO 18898

The hardness of a roller covering has traditionally been determined on the finished roller, since it is this hardness that is critical to the correct functioning of the roller in its end application. Values of hardness, determined by whichever method is chosen, are therefore dependent not only on the method employed and on the rubber, but also on the diameter of the roller, on the thickness of the covering and, in the case of thin coverings, on the nature of the roller core. For this reason the term “apparent hardness” is used to distinguish between the values obtained by the methods described in the various parts of this document and those that would be obtained for the rubber if it was possible to use the standard test methods for standard test pieces forming the subjects of other International Standards.

Since rollers vary considerably in size, construction and end use, and in view of the fact that hardness determinations are made for such different purposes as specification and factory process control, it has not been possible to standardize one test method. Consequently, three methods are described in ISO 48-6, ISO 48-7 and ISO 48-8, each capable of standing alone.

1 Scope

This document specifies a method for the determination of the apparent hardness of vulcanized- or thermoplastic-rubber roller covers, expressed as the Pusey and Jones indentation value.

The Pusey and Jones plastometer apparatus is used to measure the depth of indentation of an indentor under a specified force into the surface of the rubber. The indentation value is not the same as that measured by the international rubber hardness test method ISO 48-2, since in this method the rubber immediately adjacent to the indentor is precompressed. The Pusey and Jones indentation value is an inverse measurement of hardness, i.e. the harder the rubber the lower the Pusey and Jones indentation value.

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

For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

Bibliography