MarineLine® E-Newsletters

Profitable Tanker News about Marine Cargo Tank Coatings
Issue 18
1st in a 2-Part Series on...
The Reason MarineLine® is Better is Because of a Better Chemical Structure

CoatingOne of the questions customers ask Advanced Polymer Coatings (APC) is “What makes the MarineLine® cargo tank coating better than other tank coatings?” This two-part series will answer that question.

The answer begins with understanding basic polymer and coatings chemistry. A coating is a thin layer of material deposited on a substrate to provide various surface properties. For protective coatings, key performance features are corrosion protection, high temperature resistance, low surface energy (for easy cleaning), and others. By using the right chemistry, these properties can be achieved.

Setting THe Bar High for a Cargo Tank Coating
The Problem

Aggressive chemical molecules penetrate into an ‘open screen’ coating causing absorption and swelling. This leads to subsequent cargo contamination and also substrate corrosion.

The Goal

Create a high density ‘closed-screen’ coating allowing virtually no penetration, providing high chemical resistance. An ultra-smooth surface ensures easy, fast cleaning.

Cargo Tank Coating Cross Section

For many years, APC studied a range of polymers and coatings for various applications. This research into epoxies, phenolics, vinylesters, polyesters and zincs, was done to determine what chemical matrixes produced successes, and what weaknesses eventually led to failures or reduced capability to handle aggressive chemicals. A key finding showed that to increase a polymer’s chemical and temperature resistance, the cross-link density of the polymer needed to be increased. The ‘tighter’ the cross-linking (number of cross-links per unit of volume), the higher the resistance. However, the result of higher cross-linking was reduced flexibility and toughness, which meant a brittle polymer, hardly ideal for a tank coating on a constantly moving marine vessel stressed by movement on the high seas. (Note: an example of a high cross-linked, yet brittle polymer, is a phenolic, which usually fails, due to non-cross-linking of some of the hydroxal groups or entrapment of water which causes delamination of coating layers.)

So this explains the basic chemistry and problems associated with coatings. In the next issue, we focus on how APC provides better coatings solutions.

For more information on how MarineLine® coating can help your tanker operations, contact your MarineLine representative.