Flow coating apparatus and method of coating
Disclosed is a flow coating apparatus, comprising a slot that can dispense a coating material in an approximately uniform manner along a distribution blade that increases uniformity by means of surface tension and transfers the uniform flow of coating material onto an inclined substrate such as for example glass, solar panels, windows or part of an electronic display. Also disclosed is a method of flow coating a substrate using the apparatus such that the substrate is positioned correctly relative to the distribution blade, a pre-wetting step is completed where both the blade and substrate are completed wetted with a pre-wet solution prior to dispensing of the coating material onto the distribution blade from the slot and hence onto the substrate. Thereafter the substrate is removed from the distribution blade and allowed to dry, thereby forming a coating.
1. A method of coating a substrate comprising:
cleaning or otherwise increasing the surface energy of a surface of the substrate such that a coating material will evenly wet the surface when the coating material is applied to the surface;
positioning the substrate adjacent to a coating distribution blade;
wetting the distribution blade and the substrate with a pre-wet solution;
dispensing a coating material from a slot onto the distribution blade, wherein the coating material flows by gravity down the distribution blade onto the surface of the substrate, and wherein the coating material flows from the top to the bottom of the surface of the substrate, leaving a layer on the substrate.
2. The method of claim 1 , further comprising removing the substrate from the distribution blade and allowing it to dry.
3. The method of claim 1 , further comprising collecting excess coating material from the bottom of the substrate.
4. The method of claim 1 , further comprising pressing the substrate against the distribution blade such that the distribution blade conforms to the substrate or the substrate conforms to the distribution blade.
5. The method of claim 1 , wherein the pre-wet solution comprises a mixture of solvents chosen to provide the following properties. The viscosity is within ±50% of the viscosity of the coating material and more preferably within ±10% and even more preferably within ±2% and/or the surface tension is within ±50% of the surface tension of the coating material and more preferably within ±10% and even more preferably within ±2% and/or the vapor pressure is within ±50% of the vapor pressure of the coating material and more preferably within ±10% and even more preferably within ±2%.
6. The method of claim 1 , wherein the distribution blade and/or substrate are allowed to dry or partially dry before the substrate is removed from the distribution blade.
7. The method of claim 1 , further comprising placing a drip guard is placed between the substrate and the distribution blade after the substrate is removed from the distribution blade.