ISO 4660:2020 pdf download Rubber, raw natural — Colour index test
1 Scope
This document specifies two methods to determine the colour of raw natural rubber according to astandard colour scale:
– Method A: colour matching against standard coloured glasses;—Method B: colour determination using colour spectrophotometer.In case of dispute, the preferred method is Method B.
2Normative references
The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document. For dated references,only the edition cited applies.Forundated references, the latest edition of the referenced document (including any amendments) applies.ISo 2393,Rubber test mixes — Preparation, mixing and vulcanization — Equipment and procedures
3Terms and definitions
No terms and definitions are listed in this document.
IlS0 and IEC maintain terminological databases for use in standardization at the following addresses:- ISO online browsing platform: available at https:.//www.iso.org/obp
—IEC Electropedia: available at http:.//www.electropedia.org/
4 Principle
The raw rubber is prepared in the form of a moulded disc of specified thickness.
For Method A, the colour of this disc is compared and matched as closely as possible with that ofstandard glasses.Colour matching is carried out under diffuse daylight illumination against a mattwhite background, preferably by use of a comparator which suitably locates and shrouds the test pieceand standard glass.
For Method B, the colour of the test piece is compared and matched automatically using a colourspectrophotometer.
Annex Agives additional information on comparison study between Method A and Method B.
5 Apparatus
The usual laboratory apparatus and, in particular, the following.
5.1 Laboratory mill, conforming to the requirements of lSO 2393.ISO 4660:2020 pdf download