Recommended Methods for the Analysis of Alkyd Resins

Abstract

This is the second publication of the Subcommittee on Analytical Methods of the Organic Coatings Section, the first being 'Recommended Methods for the Analysis of Drying Oils'. The trend of the Organic Coatings industry has been to use oil-modified resins, particularly alkyd resins, in place of the simpler drying oils and this has brought the need for standard methods for analysis of these resins. The methods chosen for investigation were those considered to be of most importance in current practice. Of the chemical methods, particular attention has been given to the method for the determination of hydroxyl value, on which there were conflicting views. In a cooperative exercise, laboratories in five countries obtained highly satisfactory results by two methods and since there was little to choose between them both are included. As envisaged in the earlier publication, increasing use is made of instru- mental (chromatographic and spectroscopic) methods. In the present state of development they are of main value for qualitative or semi-quantitative analysis. The gas chromatographic methods were the subject of a further cooperative investigation involving laboratories in five countries. The methods for the determination of phthalic anhydride content and fatty acids content are essentially equivalent to those of A.S.T.M. D563—52 and D1398—58 respectively.