Abstract:
A method for using a coating apparatus (10) to improve productivity and reducing material waste when a continuous flow of a coating liquid onto a web (12) is desired and when the continuous flow is intentionally stopped to address a coating problem or to end, or temporarily postpone, a coating session. The method includes the use of flow control means (22) which enables the continuous flow to be quickly and cleanly started and stopped to address a coating problem or to end or temporarily postpone the coating session.
Abstract:
A method of preparing a surface on a die coater (20) to improve the uniformity of the coating layer on the substrate (24). A surface (42) of the die block (28) is machined. The die block (28) is then positioned on a measuring surface in a free state so that the machined surface (42) being measured is substantially vertical. The vertical orientation of the die block (28) substantially removes the effect of gravity on any residual stress during measuring. The steps of machining, positioning, and measuring the die block (28) are repeated until the desired total indicated run-out is achieved. The positioning step may also include interposing at least two point supports (70) between the die block (28) and the measuring surface. In another embodiment, the die blocks (28) are positioned in a reference state or a production state for measuring.
Abstract:
A method of depositing a magnetic recording media coating onto a substrate, wherein the coating is substantially free of Benard Cells, the method comprising the steps of: (a) providing a dispersion comprising a polymeric binder, a pigment, and a solvent; (b) coating the dispersion onto a surface of the substrate; (c) drying the dispersion; (d) calculating values comprising ν, β, and d representing the viscosity, temperature gradient, and wet caliper of the dispersion, respectively; and (e) during the course of carrying out steps (a), (b) and (c), maintaining the ratio βd2/ν below a threshold value sufficient to substantially prevent the formation of Benard Cells in the magnetic recording media coating.