Rubber, vulcanized or thermoplastic — Determination of dead-load hardness using the very low rubber hardness (VLRH) scale

Caoutchouc vulcanisé ou thermoplastique — Détermination de la dureté sous charge constante au moyen de l'échelle de très faible dureté (VLRH)

General Information

Status
Withdrawn
Publication Date
19-Jun-2012
Withdrawal Date
19-Jun-2012
Current Stage
9599 - Withdrawal of International Standard
Completion Date
20-Aug-2018
Ref Project

Relations

Buy Standard

Standard
ISO 27588:2012 - Rubber, vulcanized or thermoplastic -- Determination of dead-load hardness using the very low rubber hardness (VLRH) scale
English language
9 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 27588
Second edition
2012-06-15
Rubber, vulcanized or thermoplastic —
Determination of dead-load hardness using
the very low rubber hardness (VLRH) scale
Caoutchouc vulcanisé ou thermoplastique — Détermination de la dureté
sous charge constante au moyen de l’échelle de très faible dureté (VLRH)
Reference number
ISO 27588:2012(E)
ISO 2012
---------------------- Page: 1 ----------------------
ISO 27588:2012(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2012

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO’s

member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 27588:2012(E)
Contents Page

Foreword ............................................................................................................................................................................iv

Introduction ........................................................................................................................................................................ v

1 Scope ...................................................................................................................................................................... 1

2 Normative references ......................................................................................................................................... 1

3 Principle ................................................................................................................................................................. 1

4 Apparatus .............................................................................................................................................................. 1

5 Calibration ............................................................................................................................................................. 2

6 Test pieces ............................................................................................................................................................ 2

7 Time interval between forming the test pieces and testing ..................................................................... 2

8 Conditioning ......................................................................................................................................................... 2

9 Temperature of test ............................................................................................................................................. 2

10 Procedure .............................................................................................................................................................. 3

11 Test report ............................................................................................................................................................. 3

Annex A (normative) Relationship between indentation depth and hardness, and derivation of the

VLRH scale ............................................................................................................................................................ 4

Annex B (normative) Calibration schedule.................................................................................................................. 7

Bibliography ....................................................................................................................................................................... 9

© ISO 2012 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 27588:2012(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies

(ISO member bodies). The work of preparing International Standards is normally carried out through ISO

technical committees. Each member body interested in a subject for which a technical committee has been

established has the right to be represented on that committee. International organizations, governmental and

non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International

Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 27588 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee

SC 2, Testing and analysis.

This second edition cancels and replaces the first edition (ISO 27588:2008), which has been revised to include

a calibration schedule for the apparatus used (see Annex B).
iv © ISO 2012 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 27588:2012(E)
Introduction

The hardness test specified in this International Standard is intended as a more discriminating alternative to

the international rubber hardness degrees scale (ISO 48) for rubbers below 35 IRHD. A durometer method for

soft rubbers is described in ISO 7619-1 as the AO scale. Examples of applications are low-modulus bearings,

soft roller coverings and printing rubbers.

Figure 1 shows a comparison of the ranges of the IRHD N and IRHD L methods in ISO 48 with the VLRH scale

of this International Standard.

The methods differ primarily in the diameter of the indenting ball and the magnitude of the indenting force,

these being chosen to suit the particular application.
Figure 1 — Comparison of the ranges of hardness measurement methods for rubber
© ISO 2012 – All rights reserved v
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 27588:2012(E)
Rubber, vulcanized or thermoplastic — Determination of dead-
load hardness using the very low rubber hardness (VLRH) scale

WARNING — Persons using this International Standard should be familiar with normal laboratory

practice. This standard does not purport to address all of the safety problems, if any, associated with

its use. It is the responsibility of the user to establish appropriate safety and health practices and to

ensure compliance with any national regulatory conditions.
1 Scope

This International Standard specifies a dead-load method for the determination of the hardness of very soft

vulcanized or thermoplastic rubbers using the very low rubber hardness (VLRH) scale.

The relation between the depth of penetration and the VLRH scale is linear.
2 Normative references

The following referenced documents are indispensable for the application 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.
ISO 18898:2012, Rubber — Calibration and verification of hardness testers
ISO 18899, Rubber — Guide to the calibration of test equipment

ISO 23529, Rubber — General procedures for preparing and conditioning test pieces for physical test methods

3 Principle

The hardness test consists of measuring the difference between the depths of indentation of a ball into the

rubber under a small contact force and a large total force. From this difference, the hardness in “very low

rubber hardness degrees” (VLRH) is obtained using Table A.1 (see Annex A) or graphs based on this table

or a scale, reading directly in very low rubber hardness degrees, calculated from the tables and fitted to the

indentation-measuring instrument.
4 Apparatus

The essential parts of the apparatus are as follows, the appropriate dimensions and forces being shown in

Table 1. Detailed information can be found in References [1] and [2].

4.1 Vertically guided plunger, having a ball or spherical surface on the lower end, and means for supporting

the plunger so that the spherical tip is kept slightly above the surface of the annular foot prior to applying the

contact force.

4.2 Means for applying a contact force and an additional indenting force to the plunger, making

allowance for the mass of the plunger, including any fittings attached to it, and for the force of any spring acting

on it, so that the forces actually transmitted through the spherical end of the plunger are as specified.

4.3 Means for measuring the increase in depth of indentation of the plunger caused by the indenting

force, either in millimetres with a maximum uncertainty of 0,001 mm, or reading directly in VLRH with a resolution

such that a reading to at least 0,5 VLRH is possible.
© ISO 2012 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO 27588:2012(E)

4.4 Flat annular foot, normal to the axis of the plunger and having a central hole for the passage of the

plunger. The foot rests on the test piece and shall be rigidly connected to the indentation measurement device

so that a measurement is made of the movement of the plunger relative to the foot (i.e. the top surface of the

test piece), not relative to the surface supporting the test piece.

If it is required that measurements be made on test pieces with a curved surface, a calibration has to be carried

out. Tests need to be made on test pieces of the material with both flat and curved

...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.