Method for preparing a coating hopper prior to initiation of coating

A method for preparing a coating slide hopper prior to initiation of coating a liquid coating composition at a predetermined coating flow rate onto a moving substrate, the coating slide hopper having at least two internal flow paths therethrough exiting to a slide surface, the method comprising the steps of:

• (a) supplying a plurality of coating compositions each from a different source vessel, each different source vessel supplying coating composition to a respective one of the at least two internal flow paths;
• (b) introducing the liquid coating compositions respectively into each of the at least two internal flow path at a respective purge flow rate, the at least two internal flow paths not being water filled at the beginning of the introducing step;
• (c) filling the at least two internal flow paths with the respective liquid coating compositions and discharging the liquid coating compositions from the at least two internal flow paths through respective exit slots of the coating hopper, the liquid coating compositions flowing over a lip of the coating hopper at the purge rate to a drain;
• and
• (d) maintaining the flow of the liquid coating composition through the at least two internal flow paths at the respective purge rate until air within the at least two internal flow paths has been displaced from the coating hopper;
• and wherein
• (e) the introducing step is performed to the at least two internal flow paths such that liquid composition is delivered to a lowest one of the exit slots first, and subsequently and sequentially to the exit slots positioned higher on the slide surface.

A method for preparing a coating slide hopper prior to initiation of coating a liquid coating composition at a predetermined coating flow rate onto a moving substrate, the coating slide hopper having at least two internal flow paths therethrough exiting to a slide surface, the method comprising the steps of:

• (a) supplying a plurality of coating compositions each from a different source vessel, each different source vessel supplying coating composition to a respective one of the at least two internal flow paths;
• (b) introducing the liquid coating compositions respectively into each of the at least two internal flow path at a respective purge flow rate, the at least two internal flow paths not being water filled at the beginning of the introducing step;
• (c) filling the at least two internal flow paths with the respective liquid coating composition and discharging the liquid coating compositions from the at least two internal flow paths through respective exit slots of the coating hopper, the liquid coating, compositions flowing over a lip of the coating hopper at the purge rate to a drain;
• and
• (d) maintaining the flow of the liquid coating compositions through the at least two internal flow paths at the respective purge rates until air within the at least two internal flow paths has been displaced from the coating hopper;
• and wherein
• (e) the introducing step is performed to the at least two internal flow paths such that initial flow of liquid composition arrives at respective slots of the at least two internal flow paths substantially simultaneously;
• (f) prior to the supplying step, draining the internal flow paths, and prior to the draining step, flushing the at least two internal flow paths of the coating hopper with water;
• (g) interrupting the flushing step;
• (h) applying a surfactant to the slide surface and the lip of the coating hopper;
• and
• (i) resuming the flushing step.