EN ISO 6744-4:2004 PDF

Overview

EN ISO 6744-4:2004 (ISO 6744-4:1999) specifies a laboratory method to determine the fatty acid content of alkyd resins, a key parameter for binders used in paints and varnishes. This part is intended to be used in conjunction with ISO 6744-2 and ISO 6744-3, which cover the preceding analytical steps (saponification and removal of unsaponifiable matter). The method is not applicable to modified alkyd resins or to resins containing benzoic acid.

Key Topics

• Principle: Fatty acids are determined after saponification, removal of unsaponifiable matter and extraction into diethyl ether. The fatty acid content is the mass of residue recovered after evaporation of the ether extract, expressed as a percentage of the test portion.
• Reagents & apparatus: Use analytical-grade reagents and grade 3 water (ISO 3696). Key items include diethyl ether (stabilized with hydroquinone), acetone, hydrochloric acid (~73 g HCl per litre), silver nitrate solution (~10 g/l), a 250 ml separating funnel, rotary evaporator or water-bath distillation apparatus, and a vacuum oven capable of ~60 °C.
• Procedure summary: Analysis is carried out in duplicate. Following ISO 6744-2 and -3 workflows, acidify the aqueous solution, perform triple extraction with diethyl ether, wash extracts until no chlorides are detected with silver nitrate, evaporate the ether, remove residual water with acetone if needed, and dry the residue to constant mass.
• Calculation: Fatty acid content (percent by mass) = (mass of residue / mass of test portion) × 100. For resin solutions, calculate on the basis of non-volatile matter.
• Reporting: Reports should reference ISO 6744-4, identify the product tested, provide results, note any deviations, and record the test date.

Applications

• Quality control of alkyd resins used in paints and varnishes to ensure consistent formulation and performance.
• Raw-material verification during manufacturing and incoming inspection.
• Support for formulation development, regulatory documentation and cross-referencing with other ISO/CEN paint and varnish test methods.

Related Standards

• ISO 6744-1:1999 - General methods of test for alkyd resins.
• ISO 6744-2:1999 - Determination of phthalic anhydride content (saponification step reference).
• ISO 6744-3:1999 - Determination of unsaponifiable matter content (preceding extraction steps).
• ISO 3696:1987 - Water for analytical laboratory use (purity specification).

This method provides a reproducible, standardized approach for fatty acid analysis in unmodified alkyd resins and supports robust quality assurance in coating material production and testing.