Effect of short oil‐length alkyd additive on the properties of coal tar binder

Abstract

Purpose

Demands for coatings with superior technical characteristics have induced the use of composite coatings, which usually represent an extremely strong product. The resin blend technique is a simple and useful method for improving paint properties. Coal tar resins are the most economical coating extensively used in the industry; short oil‐length alkyd resins are usually used for air and force‐dry industrial coatings for metal surfaces. The purpose of this paper is to evaluate coating blends composed of these resins, in particular, the effects of short oil‐length alkyd additive on the properties of coal tar binder.

Design/methodology/approach

One way to achieve new types of binders is to make combinations of the existing ones, in an ideal case retaining the desirable properties of both. The alkyd has important properties over the original drying oil. To achieve the goal of improving coal tar resin properties, short oil‐length alkyd was blended with it. The prepared short oil‐length alkyd was characterised using IR and ¹HNMR spectroscopy. The mixing ratio of short oil‐length alkyd with coal tar was up to 25 per cent. The compatibility of coating blend was characterised by scanning electron microscope. The physical, mechanical and chemical properties of the coating blend in addition to the corrosion resistance were determined according to ASTM methods.

Findings

In spite of a large number of synthetic resins being available for use in paint formulations, the alkyd resins surpassed all of them in versatility and low cost. The blend of short oil‐length alkyd resin with coal tar has yielded better coating blend properties. The coating blend showed significant enhancement of physical, mechanical and chemical properties such as gloss, drying time, adhesion, scratch hardness, acid and solvent resistance because the coating blend combines the properties of thermosetting and thermoplastic resins.

Research limitations/implications

Alkyd resins are the most extensively used synthetic polymers in the coating industry. Modification of coal tar blend based on other type of polyester resins could also be studied in order to assess the applicability of the coal tar blend system found for other applications.

Practical implications

These types of alkyd resins can be applied in other bitumen composites as additives and reinforce agent.

Originality/value

The paper shows how the low‐cost modified coal tar binder can be used for air and force‐dry industrial coatings for metal surfaces.

Citation

Abd El‐Wahab, H., Abd El‐Hai, F., Abd El‐Fattah, M. and Lin, L. (2011), "Effect of short oil‐length alkyd additive on the properties of coal tar binder", Pigment & Resin Technology, Vol. 40 No. 5, pp. 305-310. https://doi.org/10.1108/03699421111176216