Silicate glasses are named as such because it is the empirical SiO2 unit that forms the majority of the glass structure. Silica is there for referred to as the network former. Unlike...
Glassflake can announce the launch of smaller diameter Glassflake for thin film coatings, with reduced particle size while maintaining a high aspect ratio material. Utilising the thin flake available from manufacturing by the rotary production method, Glassflake can produce thin flakes of glass – typically to 1 micron thickness for coatings applications and process these to have low diameters of D50 10 microns. Such a low diameter flake product would simply not be feasible with any higher thickness, given that the aspect ratio would be much lower and not offer the barrier properties glassflake is so crucial in providing.
The use of glassflake in thin film coatings has traditionally been difficult, the relatively large particle diameters can lead to performance issues as well as aesthetic complaints. Guidelines suggest that the grade of flake used should have average diameters of no greater than 50% of the coatings DFT target. Where these limits are exceeded, there is the potential to ‘wick’ moisture and ions to the substrate via mis-aligned flakes and create surface disruption, leading to a matt or orange peel surface finish. This most prevalent in developing industries of wood coatings and the automotive sector.
With thinner and smaller flakes, it is possible to build an effective barrier of overlapping glass into the coating structure, provided protection to the substrate from corrosive ions and damaging chemicals, as well as provide physical reinforcement to the film. Retention of the performance benefits of Glassflake is key and this is afforded by use of unique ECR-type Glassflake of 1 micron thickness, only manufactured using the rotary process.
There is still a place for lower aspect ratio Glassflake, such as the GF005-20 grade. While high aspect ratio flake provides excellent barrier properties, some of the most impressive abrasion and wear resistance comes from grades such as this. The low aspect ratio has excellent packing behaviour in a coating film – ideal for floor coating applications. In this further instance, using smaller diameter Glassflake for thin film coatings can reduce working time of the coating and speeding up site work to progress – key in large construction projects.