Overview
EN ISO 591-1:2000 - "Titanium dioxide pigments for paints - Part 1: Specifications and methods of test (ISO 591-1:2000)" is a CEN-adopted International Standard that specifies requirements and test methods for titanium dioxide (TiO2) pigments used in paints. It defines classification by crystal type (anatase and rutile), grade designations, essential and conditional physical/chemical characteristics, sampling rules and two validated analytical methods for determining TiO2 content.
Keywords: EN ISO 591-1:2000, titanium dioxide pigments, TiO2, pigments for paints, specifications, methods of test, anatase, rutile, paint raw materials.
Key Topics and Requirements
- Scope and classification
- Covers Type A (anatase) and Type R (rutile) titanium dioxide pigments and grades (A1, A2; R1, R2, R3).
- Essential characteristics
- Titanium dioxide content (TiO2), minimum by mass: A1 98%, A2 92%, R1 97%, R2 90%, R3 80% (see Clause 7 for test procedures).
- Matter soluble in water (hot extraction), specified maximums per grade (values defined in the standard).
- Residue on 45 μm sieve: specified maximum (0.1% by mass).
- Matter volatile at 105 °C - applicable where specified by agreement; test per ISO 787-2.
- Conditional characteristics
- Colour matching to an agreed reference, scattering power, pH of aqueous suspension, oil absorption, resistivity of aqueous extract, and matter volatile after preconditioning (applies only if contractually specified).
- Sampling and reporting
- Representative sampling per ISO 15528; test report content specified.
- Determination of TiO2 content
- Method A (aluminium reduction): dissolution in sulfuric acid, reduction of Ti(IV) to Ti(III) with aluminium under CO2, titration with ammonium iron(III) sulfate using thiocyanate indicator - suitable for single determinations and routine analysis.
- Method B (Cr(II) chloride / zinc amalgam): alternative, automatable routine method; either method may be used as referee by agreement.
Applications and Users
Who uses EN ISO 591-1:2000:
- Pigment manufacturers (quality control and product specification)
- Paint and coatings formulators (raw material acceptance and performance specification)
- Independent test laboratories and QC analysts (batch testing, dispute resolution)
- Procurement, standards and regulatory bodies (contractual specs and compliance)
Practical uses include batch release testing, supplier contracts, comparative evaluation of pigments (anatase vs rutile), and laboratory method standardization.
Related Standards
Normative references included in EN ISO 591-1:2000:
- ISO 787 series (general methods of test for pigments and extenders: e.g., ISO 787-2, -3, -5, -9, -18, -24, -25)
- ISO 1042 (volumetric flasks), ISO 3696 (water for analytical use)
- ISO 15528 (sampling of paints, varnishes and raw materials)
Use this standard to ensure consistent, reproducible testing and to specify TiO2 pigment quality in paint formulations and supply agreements.
