Patent ID: 6458421
Filing Date: 2002-10-01
Classification: B05C,B05D,G03C,Y10S

Abstract:
A method for reducing coating defects caused by strikethrough when simultaneously slide coating at least a first fluid layer, a second fluid layer, a third fluid layer, and a fourth fluid layer, the first fluid layer being made of a first fluid which includes a first solute and a first solvent, the second fluid layer being made of a second fluid which includes a second solute and a second solvent, the third fluid layer being made of a third fluid which includes a third solute and a third solvent, the fourth fluid layer being made of a fourth fluid which includes a fourth solute and a fourth solvent, the method comprising:preparing the first fluid having a first density; preparing the second fluid, wherein the second solute is compatible with the first solute, and the second fluid has a second viscosity and a second density; preparing the third fluid, wherein the third solute is incompatible with the first solute, and the third fluid has a third density; preparing the fourth fluid, wherein the fourth solute is incompatible with the first solute, and the fourth fluid has a fourth density; flowing the first fluid down a first slide surface to create the first fluid layer on the first slide surface, the first slide surface being positioned adjacent a substrate; flowing the second fluid down a second slide surface positioned relative to the first slide surface such that second fluid flows from the second slide surface to above the first slide surface onto the first fluid layer to create the second fluid layer on the first slide surface; flowing the third fluid down a third slide surface positioned relative to the first and second slide surfaces such that the third flows from the third slide surface to above the second slide surface onto the second fluid layer and such that the third fluid flows above the first slide surface to create the third fluid layer on the first slide surface; flowing the fourth fluid down a fourth slide surface positioned relative to the first, second, and third slide surfaces such that the fourth fluid flows from the fourth slide surface to above the third slide surface onto the third fluid layer and such that the fourth fluid flows above the second and first slide surfaces to create the fourth fluid layer on the first slide surface; and coating the substrate with the first, second, third, and fourth fluids; wherein the incompatibility of each of the third and fourth solutes with the first solute makes at least one of the third and fourth fluids susceptible to strikethrough to at least one of the second and first slide surfaces, and wherein at least one of the third and fourth densities is greater than the second density, and wherein the second viscosity is sufficient to reduce the strikethrough of at least one of the third and fourth fluids to at least one of the second and first slide surfaces.