Abstract

Wax additives are an essential part of any ink and coating formulator’s toolkit. Micronized wax powders, dispersions and emulsions can improve the durability of all types of surface coatings, imparting slip, abrasion and scratch resistance, anti-blocking, and rub resistance. Most commercial wax additives are based on synthetic materials including polyethylene and polypropylene. In the last few years, there has been a growing trend to develop formulated systems that contain higher percentages of materials that are bio-based, renewable, and/or biodegradable.

Historically, the only commonly used wax additive that qualifies as bio-based and renewable would be carnauba wax. This natural wax, derived from the Brazilian Palm, is freshwater biodegradable based on OECD 302 testing. Dry powders based on carnauba wax can provide slip and lubricity with good film clarity. Emulsions of carnauba wax can improve water beading in high gloss coatings with slip, anti-blocking and mar resistance.

Another class of wax additive that offers significant biocontent would be ethylene bis-stearamide, or EBS wax. This material typically contains around 90% stearic acid, which can be derived from both animal and plant sources. Most formulators prefer an EBS that is based on plant-derived stearic acid, especially for food packaging applications. EBS can be used as the sole was powder but is often more effective when contained in a composite wax powder, where multiple components are melted together and homogenized prior to milling into an ultrafine powder.

Beyond carnauba wax and EBS, there have been limited options available to formulators looking to increase the natural content of an ink or coating.