Browse Prior Art Database

Coater with Upper and Lower Pan

IP.com Disclosure Number: IPCOM000045489D
Original Publication Date: 1983-Mar-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Terwilliger, HW: AUTHOR

Abstract

On a standard three-roll reverse coater (Fig. 1), the two lower rolls (metering 1 and applicator 3) dip into the coating solution. When the solution consists of highly volatile (fast) solvent and has a high solids content, a crust will form on the surface and build up on the ends of the rolls. This is avoided by the two-level system of Fig. 2, in which the applicator roll 3 dips in a small, upper pan 5 and the metering roll is above the liquid of the larger, lower pan 7.

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Coater with Upper and Lower Pan

On a standard three-roll reverse coater (Fig. 1), the two lower rolls (metering 1 and applicator 3) dip into the coating solution. When the solution consists of highly volatile (fast) solvent and has a high solids content, a crust will form on the surface and build up on the ends of the rolls. This is avoided by the two-level system of Fig. 2, in which the applicator roll 3 dips in a small, upper pan 5 and the metering roll is above the liquid of the larger, lower pan 7.

When crust can form, as in the Fig. 1 system, it will break loose and be picked up by applicator roll 3. This can cause a streak. The crust also can pass through the metering roll gap and make a blob on the coating surface. Only a very few defects of this type can ruin a coating run. The two-level pan system of Fig. 2 eliminates the problems of floating, solidified material causing coating defects.

This is accomplished by several features of this pan system as follows:

1) Only applicator roll 3 is in contact with the coating material in the upper pan 5.

2) Upper pan 5 has a very small surface area exposed when in operation. The front lip of this pan is located 1/8 to 1/4 inch from roll 3. This lip must be level with the lowest part of the pan so that the surplus coating material will overflow evenly across the width of the pan.

3) Coating material is pumped in excess of what is needed for coating so that it flushes under and around applicator roll 3 to give it cont...