How to apply and cure silicone coatings - tutorial

Tutorial – How to apply and cure silicone coatingsTypical Application MethodsTypical methods for the application of silicone coatings to fabric include:• Knife coating (knife-over-roll, knife-over-gap/air or knife-over-blanket)(Figure 1)-W ith knife-coating methods, the outcome is influenced by bladetype and angle as well as the substrate. (Figure 2)Figure 4 – Rotogravure coating.•D ip/immersion coating or kiss coating (lick roll) (Figure 3)•Rotog ravure coating (Figure 4)-T he gravure process ensures that the topcoat is delivered at aconstant application rate and is not affected by substrate variability.This method facilitates higher line speeds.• Extrusion (Figure 5)• Spraying (Figure 6) Figure 1 – Knife coating.The use of opposing knives orknife-over-air methods facilitatessubstrate penetration. Figure 5 – Extrusion.Squeeze-roll, reverse-roll andknife-over-roll methods facilitatefilm forming. In squeeze- andreverse-roll methods, roll pressuregoverns the deposition of the film.Knife-over-roll, on the other hand,relies on blade type and angle.Figure 2 – Knife shapes.Figure 6 – Spraying.Figure 3 – Dip/immersion coating or kiss coating.Liquid silicone rubbers (LSRs)LSRs are usually sold as two-component systems (kits). Mix ratios varyfrom 1:1 to 10:1.For laboratory trials, LSR can be mixed with a laboratory mixer or by hand.Pot life will vary depending on the amount of inhibitor in the formulation. Toavoid air bubbles, the mixture must be ...