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ABSTRACT:

Waterborne Alkyd Coatings - Moving Towards a Sustainable Future?

Since the development of alkyd resins in 1920s, alkyd-based enamel paints have remained one of the most significant categories of surface coatings. Alkyd resins can be regarded as a class of oil-modified condensation polyesters. Incorporation of fatty-oils or fatty-acid within the polyesteric structure of the polymeric chains have resulted in more flexible, air-drying, and glossy coatings.  The presence of oil component in alkyd binders can also contribute additional value in terms of sustainability. Water-based (WB) alkyd dispersions and emulsions are gradually replacing traditional alkyd resins due to a growing understanding of the negative impacts solvent-based coatings have on the environment and human health. To this date, various WB alkyd technologies have been developed; however, the uptake of waterborne architectural paints based on alkyds has been slow in the local market.  

The properties of selected technologies has been evaluated and compared to traditional solventborne alkyd and waterborne acrylic systems.  This includes coatings based on alkyd emulsions, urethane-modified alkyds and acrylic-urethane modified alkyds. Film formation properties were compared in terms of drying time, hardness development and gloss.  Coating rheology and binder-additive interactions were also investigated to improve compatibility and product stability.  The results of this work and relative strengths and weaknesses of the different technologies will be presented. 

BIOGRAPHY:

Hamid is a Research and Development Chemist at Resene Paints. He holds BSc, MSc, and PhD in Polymer Engineering, with a specialization in Colour Science and Technology. Originally from Iran, Hamid began his industrial career working on the synthesis of water-based acrylic emulsions. He is recognized within the Iranian technical community as the first developer of polycarboxylate-type superplasticizers for cementitious admixtures. He then further expanded the applications of polycarboxylate additives to textiles, water treatment, and ceramics. After relocating to New Zealand in 2019, Hamid has worked with researchers from Massey University in joint projects focused on the preparation and colloidal stabilization of food-grade pigments. His scientific interests centre around applied surface chemistry and rheology, and he thrives on the challenges of developing innovative surface coating formulations.