Fluorine in coatings

Citation

Bean, J. (2001), "Fluorine in coatings", Pigment & Resin Technology, Vol. 30 No. 2. https://doi.org/10.1108/prt.2001.12930baa.001

Fluorine in coatings

Fluorine in coatings

Keywords: Coatings, Solvents, Additives

The use of fluorinated materials in coatings is often only considered as a last resort, the reason being that they are viewed as expensive materials. However, the conclusions from a "Fluorocoat" conference just held in Brussels are that fluorinated materials are, in fact, often the most economic solution to difficult coating/protection problems. It showed that fluorochemistry can deliver advantages such as long life/low maintenance, even in situations previously regarded as "too low tech for expensive fluoromaterials".

The conference, "Fluorine in coatings IV", was held 5-7 March 2001. The main organiser was the PRA, from whom copies of the papers can be purchased: 8 Waldegrave Road, Teddington, Middlesex TW11 8LD, UK. Tel: +44 (0) 20 8 614 4811; Fax: +44 (0) 20 8 614 4812; www.fluorocoat2001.com

The total global market for fluoropolymers is approaching 100,000 tons with PTFE accounting for 62,000 tons of this total. However, more and more use is being made of fluoro-modified resins, using fluoromonomers and oligomers, fluorosurfactants and elemental fluorine for direct surface fluorination. The fluoromonomers and oligomers may be more expensive per kilo than solid polymers, but may be used in smaller quantities in larger volume coating formulations. The economics are improving further as newer processes allow the controlled engineering of thin film fluoro-rich surfaces and direct surface fluorination so that the products are placed at the point of need. Novel environmentally friendly application methods such as "dry paint film" point the way to the future.

Here are just a few abstracts of the 33 papers presented.

Polymer compatibility and coating performance of polyvinylidene fluoride. By Dr Shiow-Ching Lin, Ausimont, USA.

This paper reviewed the miscibility of PVDF with various organic polymers. The utilisation of PVDF miscibility for the design of PVDF coating compositions to maximise coating performance was considered. The focus was on thermoplastic and thermoset acrylic resin systems.

Water-based fluoroelastomer coating cured by a basic polyol agent. By Yasukazu Nakatani and Koichiro Ogita, Daikin Industries, Japan.

Water-based fluoroelastomer coatings cured by dysfunctional amine or hydrolysed aminosilane have good performance properties in heat, oil and chemical resistance or weatherability, but poor elasticity and heat resistance. A coating system cured by a basic polyol agent such as water-soluble polyphenol is introduced which improves elasticity and heat resistance and also extends pot-life.

A new fluoroelastomer latex. By Dr Paul Kirochko and Dr Albert van Cleeff, Lauren International, USA.

This has been designed to give good film formation, satisfactory physical properties and high chemical resistance, and is intended to satisfy increasing demand for environmentally friendly formulations. Depending on final applications, different curing systems can be used to provide coatings with low water and acid swell, improved adhesion to various substrates and longer catalyzed pot-life.

The direct fluorination of low density polyethylene-reaction kinetics and chemistry. By Dr Reiner Täge, Dr Alexandre Kharitonov and G.G. Ferrier, Air Products, Germany.

Understanding of the chemistry and chemical kinetics involved in treatment of a surface with elemental fluorine has been limited. In this study ESR, interference and IR methodologies in addition to traditional quenching techniques were used to analyse the key process pathways. The nature and concentration of the reactive species (radicals and oxy-species) and their temperature and time dependence and the rate of formation of fluorinated layer were studied. Particular attention was paid to the nature of the initial step of the gas-surface interaction and the gas-surface interaction and the related effects of temperature.

John Bean