ISO 6916-2:2001

Flexible cellular polymeric materials - Sponge and expanded cellular rubber products - Specification - Part 2: Mouldings and extrusions

This part of ISO 6916 classifies flexible cellular rubber products known as sponge and expanded rubber. The base material used in their manufacture may be natural rubber, reclaimed rubber, synthetic rubber or rubber-like material, either alone or in combination. Thermoplastic rubbers are not included. This part of ISO 6916 does not apply to latex foam rubbers or shoe soling. Sheeting materials are covered by ISO 6916-1. This part (part 2) covers vulcanized cellular rubber products that are manufactured by a moulding or continuous vulcanization process, i.e. hot air, microwave, infra-red, liquid curing medium (LCM), shearing-head vulcanization or a combination of two or more of these methods. In the case of conflict between the provisions of this part of ISO 6916 and those of the detailed specification or test method for a particular product, the latter shall take precedence. Reference to the methods shall specifically state the desired test or tests.

Polymères alvéolaires souples — Caoutchoucs alvéolaires mousses et souples — Spécification — Partie 2: Moulage et extrusion

General Information

• Status: Withdrawn
• Publication Date: 19-Dec-2001
• ICS: 83.100 - Cellular materials
• Technical Committee: ISO/TC 45/SC 4 - Products (other than hoses)
• Drafting Committee: ISO/TC 45/SC 4 - Products (other than hoses)
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 26-Apr-2024
• Completion Date: 13-Dec-2025

Relations

• Consolidated By: ISO 1461:1999 - Hot dip galvanized coatings on fabricated iron and steel articles - Specifications and test methods
• Effective Date: 06-Jun-2022
• Revised: ISO 6916-2:2024 - Flexible cellular polymeric materials - Sponge and expanded cellular rubber products - Part 2: Specification for mouldings and extrusions
• Effective Date: 06-Jun-2022

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 6916-2
First edition
2001-12-15
Flexible cellular polymeric materials —
Sponge and expanded cellular rubber
products — Specification —
Part 2:
Mouldings and extrusions
Polymères alvéolaires souples — Caoutchoucs alvéolaires mousses et
souples — Spécification —
Partie 2: Moulage et extrusion

Reference number
©
ISO 2001
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not
be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this
file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this
area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters
were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event
that a problem relating to it is found, please inform the Central Secretariat at the address given below.

©  ISO 2001
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 [e-mail]
Web www.iso.ch
Printed in Switzerland
ii © ISO 2001 – All rights reserved

Contents Page
Foreword.iv
1 Scope .1
2 Normative references.1
3 Classification (types, classes, grades and suffixes) .2
4 Material and workmanship .3
5 Physical properties.3
6 Methods of test .3
7 Dimensional tolerances .3
8 Inspection and rejection .3
9 Packaging and marking .4
10 Sampling.4
11 Standard test pieces, standard test sheets and specially prepared extruded shapes .4
12 Measurement of test piece dimensions .5
Annex A (normative) Heat-resistance test.13
Annex B (normative) Compression deflection tests .14
Annex C (normative) Oil resistance test.15
Annex D (normative) Compression set under constant deflection .16
Annex E (normative) Water absorption test.17
Annex F (normative) Fluid resistance test .18
Annex G (normative) Low-temperature resistance test .19

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 3.
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 part of ISO 6916 may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 6916-2 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 4,
Products (other than hoses).
ISO 6916 consists of the following parts, under the general title Flexible cellular polymeric materials — Sponge and
expanded cellular rubber products ― Specification:
 Part 1: Sheeting
 Part 2: Mouldings and extrusions
Annexes A to G form a normative part of this part of ISO 6916.
iv © ISO 2001 – All rights reserved

INTERNATIONAL STANDARD ISO 6916-2:2001(E)

Flexible cellular polymeric materials — Sponge and expanded
cellular rubber products ― Specification —
Part 2:
Mouldings and extrusions
WARNING — Persons using this part of ISO 6916 should be familiar with normal laboratory practice. This
part of ISO 6916 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 part of ISO 6916 classifies flexible cellular rubber products known as sponge and expanded rubber. The base
material used in their manufacture may be natural rubber, reclaimed rubber, synthetic rubber or rubber-like
material, either alone or in combination. Thermoplastic rubbers are not included. This part of ISO 6916 does not
apply to latex foam rubbers or shoe soling.
Sheeting materials are covered by ISO 6916-1. This part (part 2) covers vulcanized cellular rubber products that
are manufactured by a moulding or continuous vulcanization process, i.e. hot air, microwave, infra-red, liquid curing
medium (LCM), shearing-head vulcanization or a combination of two or more of these methods.
In the case of conflict between the provisions of this part of ISO 6916 and those of the detailed specification or test
method for a particular product, the latter shall take precedence. Reference to the methods shall specifically state
the desired test or tests.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this part of ISO 6916. For dated references, subsequent amendments to, or revisions of, any of these publications
do not apply. However, parties to agreements based on this part of ISO 6916 are encouraged to investigate the
possibility of applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain
registers of currently valid International Standards.
ISO 188:1998, Rubber, vulcanized and thermoplastic — Accelerated ageing and heat resistance tests
ISO 815:1991, Rubber, vulcanized or thermoplastic — Determination of compression set at ambient, elevated or
low temperatures
ISO 1431-1:1989, Rubber, vulcanized or thermoplastic — Resistance to ozone cracking — Part 1: Static strain test
ISO 1817:1999, Rubber, vulcanized — Determination of the effect of liquids
ISO 1923:1981, Cellular plastics and rubbers — Determination of linear dimensions
ISO 3865:1997, Rubber, vulcanized or thermoplastic — Methods of test for staining in contact with organic material
1)
ISO 5893:— , Rubber and plastics test equipment — Tensile, flexural and compression types (constant rate of
traverse) — Specification
NOTE In some of the test methods referenced in this clause, the apparatus but not the procedure is used.
3 Classification (types, classes, grades and suffixes)
3.1 Types
Three types are specified, as follows:
Type 1: open-cell rubber
Type 2: closed-cell rubber
Type 3: self-skinned cellular rubber
3.2 Classes
Each type is divided into four classes designated by the letters A, B, C and D (for example type 1B), as follows:
Class A: Cellular rubbers made from natural rubber, where specific resistance to the action of petroleum-
based oils is not required
Class B: Cellular rubbers having specific requirements for oil resistance with low swell
Class C: Cellular rubbers having specific requirements for oil resistance with medium swell
Class D: Cellular rubbers made from synthetic rubber or rubber-like materials, either alone or in combination,
having specific requirements for both low- and high-temperature resistance (– 75 °C to + 250 °C), but where
specific resistance to the action of petroleum-based oils is not required
3.3 Grades
Each class is divided into six different grades based on a specific range of firmness as expressed by compression
deflection determined as described in annex B. Grades are designated by a digit (0 to 6), with the softer grades
being identified with the lower numbers and the harder grades with the higher numbers:
Grade 0: For type 1 cellular rubbers only, a compression deflection range of 2,5 kPa to 15,0 kPa
Grade 1: For type 1 and 2 cellular rubbers, a compression deflection range of 15,1 kPa to 35,0 kPa
Grade 2: For type 1 and 2 cellular rubbers, a compression deflection range of 35,1 kPa to 65,0 kPa
Grade 3: For type 1 and 2 cellular rubbers, a compression deflection range of 65,1 kPa to 95,0 kPa
Grade 4: For type 1 and 2 cellular rubbers, a compression deflection range of 95,1 kPa to 125,0 kPa
Grade 5: For type 1 and 2 cellular rubbers, a compression deflection range of 125,1 kPa to 200,0 kPa
Grade 6: For type 1 and 2 cellular rubbers, a compression deflection range of 200,1 kPa to 300,0 kPa

1) To be published. (Revision of ISO 5893:1993)
2 © ISO 2001 – All rights reserved

3.4 Suffixes
3.4.1 Suffix letters
Suffix letters may be added singly or in combination after any grade number to indicate additional requirements
beyond those specified in Tables 1 to 3 as basic requirements. The significance of the approved suffix letters is
shown in Table 4.
3.4.2 Suffix numbers
Each suffix letter should preferably be followed by a suffix number. The suffix number indicates the particular test
conditions. The test duration is part of the method and is taken from the listing in Table 5.
NOTE Products meeting requirements defined to the suffix number level should conform with national and supra-national
health and safety regulations.
4 Material and workmanship
4.1 Cellular rubbers produced to this part of ISO 6916 shall be manufactured from natural rubber, synthetic
rubber, reclaimed rubber or rubber-like material, together with added compounding ingredients of such nature and
quality that the product complies with the requirements of this part of ISO 6916.
4.2 In permitting choice in the use of materials, it is not intended to imply that the resulting different rubber
materials are equivalent in respect of all physical properties. Any special characteristics other than those specified
in this part of ISO 6916 that may be desired for a specific application shall be detailed in the particular product
specification. All materials and workmanship shall be in accordance with good commercial practice, and the
resulting cellular rubbers shall be free from defects affecting serviceability.
5 Physical properties
The various types, classes and grades of cellular rubber shall conform to the physical-property requirements given
in Tables 1 to 3, together with any additional requirements indicated by any suffix letter as described in Table 4 and
any suffix number given in the designation as described in 3.4.
6 Methods of test
6.1 Unless specifically stated otherwise, all tests shall be carried out in accordance with the methods specified in
the annexes to this part of ISO 6916.
6.2 Test pieces shall not be tested for at least 72 h after manufacture. Prior to testing, the test pieces shall be
stored for at least 16 h at either (23 ± 2) °C and (50 ± 5) % relative humidity or (27 ± 2) °C and (65 ± 5) % relative
humidity. This period may form the latter part of the period following manufacture.
7 Dimensional tolerances
The tolerances allowable on the dimensions of cellular rubber in moulded and extruded form shall be as specified
in Table 6.
8 Inspection and rejection
8.1 All tests and inspections shall be made at the place of manufacture prior to shipment, unless otherwise
specified. The manufacturer shall afford the inspector all reasonable facilities for tests and inspections.
8.2 The purchaser may carry out the tests and inspections governing acceptance or rejection of the material at
his own laboratory or elsewhere. Such tests and inspections shall be made not later than 15 days after receipt of
the material.
8.3 All test pieces prepared as specified in clause 11 shall be visually inspected to determine compliance with
the material, workmanship and colour requirements.
8.4 Any material that fails one or more of the test requirements may be re-tested. For this purpose, two
additional tests shall be made for the requirement for which failure occurred. Failure of either of the re-tests shall be
cause for final rejection.
8.5 Rejected material shall be disposed of as directed by the manufacturer.
9 Packaging and marking
The material shall be properly and adequately packaged. Each package or container shall be legibly marked with
the name of the material, the name or trademark of the manufacturer, and any required purchaser's designations.
10 Sampling
10.1 When possible, the complete finished product shall be used for the tests specified. Representative samples
of the lot being examined shall be selected at random as required.
10.2 When it is necessary or advisable to obtain test pieces from the article, as in those cases where the finished
product is not required or suitable for testing, the method of cutting and the exact position from which test pieces
are to be taken shall be specified. The apparent density and the state of cure may vary in different parts of the
finished product, especially if the article is of complicated shape or of varying thickness, and these factors will affect
the physical properties of the test pieces. Also, the apparent density is affected by the number of cut surfaces as
opposed to the number of skin-covered surfaces on the test piece.
10.3 When the finished product does not lend itself to testing or to the preparation of test pieces because of its
complicated shape, its small size, the presence of metal or fabric inserts, the presence of surface skins, a tendency
to adhere to metal, or for other reasons, standard test sheets shall be prepared. When differences in test values
arise due to the difficulty in obtaining suitable test pieces from the finished product, manufacturer and purchaser
may agree on acceptable deviations. This can be done by comparing results obtained with standard test pieces
and those obtained on actual products.
11 Standard test pieces, standard test sheets and specially prepared extruded shapes
11.1 Standard test pieces
+0,04 +0,04
Standard test pieces shall be discs, cut out with a die, either (30 ) mm or (19 ) mm in diameter and at least
0 0
+0,5
(6 )mm thick. The test pieces may be cut out with a revolving die using a soap solution as a lubricant. If a
lubricant is used, the test pieces shall be thoroughly dried before proceeding with testing. In some cases, it may be
necessary to freeze the cellular rubber to obtain parallel cut edges. When cut from standard test sheets, the test
pieces shall be cut from the central area as shown in Figure 1. The exact dimensions of the test pieces shall be
measured as specified in clause 12. Plied-up test pieces may be used as indicated in the test methods for
compression deflection and compression set.
NOTE Where available material widths are too small to allow standard test pieces to be cut, then smaller-diameter discs
may be used. Test results obtained on smaller discs may not be the same as on standard test pieces.
4 © ISO 2001 – All rights reserved

Dimensions in millimetres
Key
1 Nine holes, diameter 30 mm, with centres spaced 33,3 mm apart
Figure 1 — Locations from which standard test pieces are to be cut when preparing them from standard
test sheets or commercial sheets
11.2 Standard test sheets
11.2.1 Standard test sheets for all types of cellular rubber shall be (150 ± 5) mm square and (12,5 ± 0,5) mm in
thickness, made from the same compound and having the same apparent density and state of cure as the product
they represent. In all cases, the surface skin shall be left intact on both top and bottom faces of the test sheet.
Standard test sheets shall be prepared either by cutting them from commercial sheets of the specified thickness or
as described in 11.2.2 or 11.2.3.
11.2.2 When specially prepared standard test sheets of sponge rubber are required, they shall be made using the
frame shown in Figure 2 together with top and bottom plates each approximately 12,5 mm in thickness. The frame
and plates shall be made of aluminium or steel. The compound shall be cut into squares slightly smaller than the
frame cavities. The thickness shall be such as to give the required apparent density when the material is blown
during cure to fill the moulding cavities. The squares of compound shall be dusted with talc and the excess brushed
off to avoid pitting. They shall then be placed in the frame, and fabric sheeting shall be applied on the top and
bottom between the frame and the plates to allow venting of gases produced during curing. This fabric shall be a
commercial sheet with a mass per unit area of approximately 135 g/m and having approximately 2,75 ends/mm
and 2,36 picks/mm. The sheets shall be vulcanized in a platen press under conditions of time and temperature
chosen to produce the same state of cure in the standard sheets as in the finished products that they represent.
11.2.3 Where specially prepared standard test sheets of expanded rubber are required, such test sheets shall be
prepared to have approximately the same density and shall be vulcanized under conditions of time and
temperature chosen to produce the same state of cure as in the finished products that they represent.
12 Measurement of test piece dimensions
The dimensions of all test pieces shall be measured in accordance with ISO 1923.
Dimensions in millimetres
Figure 2 — Four-cavity frame for standard test sheets of cellular rubbers
6 © ISO 2001 – All rights reserved

Table 1 — Physical requirements for type 1 cellular rubbers [open-cell (sponge) rubbers]
Basic requirements
Compression deflection after conditioning — Compression set under
Compression Oil resistance
Change from original value constant deflection of 50 %
deflection at 22 h at
168 h at 22 h at 5 h at 22 h at 22 h at
25 %
(70 ±±±± 1) °C
(70 ±±±± 1) °C (150 ±±±± 2) °C (–55 ±±±± 2) °C (70 ±±±± 1) °C (100 ±±±± 1) °C
Deflection at   Change in
Grade No.
volume in
(23 ±±±± 2) °C
ISO 1817
or (27 ±± 2) °C
±±
oil No. 3
kPa % % % % % %
(limits) (limits) (limits) (max.) (max.) (max.) (limits)
Class A, non-oil-resistant
a
1A0 2,5 to 15 ± 20 — 25 15 — —
1A1 15,1 to 35 ± 20 — 25 15 — —
1A2 35,1 to 65 ± 20 — 25 15 — —
1A3 65,1 to 95 ± 20 — 25 15 — —
1A4 95,1 to 125 ± 20 — 25
...