ISO 16959:2026

International
Standard
ISO 16959
First edition
Natural rubber latex concentrate —
2026-02
Determination of zinc oxide
viscosity (ZOV)
Concentré de latex de caoutchouc naturel — Détermination de la
viscosité de l'oxyde de zinc (ZOV)
Reference number
© ISO 2026
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Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 1
6 Apparatus . 2
7 Sampling . 2
8 Procedure . 2
9 Expression of results . 3
10 Precision . 3
11 Test report . 3
Annex A (informative) Precision . 5
Bibliography . 7

iii
Foreword
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iv
International Standard ISO 16959:2026(en)
Natural rubber latex concentrate — Determination of zinc
oxide viscosity (ZOV)
WARNING — Persons using this document should be familiar with normal laboratory practice. This
document 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 determine
the applicability of regulatory limitations prior to use.
1 Scope
This document specifies a method for determining the zinc oxide viscosity of natural rubber latex
concentrate.
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.
ISO 123, Rubber latex — Sampling
ISO 124, Latex, rubber — Determination of total solids content
ISO 976, Rubber and plastics — Polymer dispersions and rubber latices — Determination of pH
ISO 1652, Rubber latex — Determination of apparent viscosity by the Brookfield test method
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
zinc oxide viscosity
ZOV
change in viscosity of latex concentrate when treated with zinc oxide in the presence of stabilising and
gelling agents under a standard test condition
4 Principle
A test portion is treated with potassium oleate and ammonium sulphate and tested for viscosity at a
prescribed interval of time after the addition of zinc oxide.
5 Reagents
Use only reagents of recognized analytical reag
...