Method for distributing liquid over a surface

• US 4,349,589 A
• Filed: 01/27/1981
• Issued: 09/14/1982
• Est. Priority Date: 04/23/1979
• Status: Expired due to Term

• Current Assignee: AT&T, Inc.
• Original Assignee: Western Electric Co., Inc. (Nokia Corporation)
• Inventors: Dinella, Donald, Haller, Albert H., Polakowski, Theodore D. Jr.
• Primary Examiner(s): Childs, Sadie L.
• Application Number:
  US06/228,842
• Time in Patent Office: 595 Days
• Field of Search: 427/428, 427/431, 427/365, 427/436, 427/359, 427/430.1, 427/360, 427/361, 427/97, 29/131, 29/132, 118/115, 118/424, 118/425, 428/447, 428/448, 428/450, 428/473, 428/425.8, 428/282, 428/906
• US Class Current: 427/359
• CPC Class Codes: B05C 11/105 by capillary action, e.g. using wicks
• CPC Class Codes: B05D 1/40 Distributing applied liquids or other fluent materials by members moving relatively to surface
• CPC Class Codes: C23C 18/1608 from pretreatment step, i.e. selective pre-treatment
• CPC Class Codes: C23C 18/1628 Specific elements or parts of the apparatus
• CPC Class Codes: G03F 7/16 Coating processes; Apparatus therefor applying coatings to base materials in general B05; applying photosensitive compositions to base for photographic purposes G03C1/74
• CPC Class Codes: H05K 3/0085 Apparatus for treatments of printed circuits with liquids not provided for in groups H05K3/02 - H05K3/46; conveyors and holding means therefor apparatus specially adapted for manufacturing assemblages of electric components, e.g. printed circuit boards, H05K13/00

Abstract

A surface of a substrate 11 (FIG. 2) is uniformly coated with a liquid L by wetting the surface with the liquid and compressibly contacting the wetted surface with an applicator member 10 having an outer layer 14 of a compressible liquid absorbing material with inverse sponge characteristics and an inner layer 13 of compliant material. Preferably the member is a roller 10 having a silicone rubber or polyurethane inner layer and a chamois outer layer. A plurality of the rollers 10 are arranged to be in compressive contact with the surfaces of a plurality of substrates 11 as the substrates are being removed from the liquid L (arrow A), the movement of the substrates 11 causing rotation (arrow F) of the rollers to apply a uniform coating of the liquid on the contacted surfaces.

Claims

1. A method of applying a uniform coating of a liquid on both outer surfaces of a flat planar substrate, comprising the steps of:

(a) initially immersing the substrate in a bath of the coating liquid, thereby wetting both outer surfaces of the substrate with the liquid;

(b) contacting each of the wet surfaces of the substrate with a liquid-applicator roller including a solid cylindrical core, an intermediate annular layer of a resilient compliant material on the core, and an outer annular layer of a compressible liquid-absorbing material composed of chamois or synthetic chamois having inverse sponge characteristics on the intermediate layer, such rollers being mounted adjacent to and parallel to the upper surface of the liquid in the bath and on opposite sides of the substrate, whereby the rollers move into engagement with the respective surfaces thereof;

(c) applying a force between the rollers and the substrate to compress the intermediate and outer layers between the solid core and the surface of the substrate to thereby deform the outer layer into a flattened section along a region of contact with each surface of the substrate, said flattened sections intersecting the surface of the liquid of the bath; and

(d) withdrawing the wet substrate from the bath between the rollers so that movement of the substrate causes rotation of the rollers out of engagement of the substrate above the surface of the liquid of the bath, whereby the uniform liquid coating is applied to both surfaces of the substrate.

2. A method as recited in claim 1, wherein the rollers are immersed in the liquid with less than half of each roller in contact with the liquid.

3. A method of applying a uniform coating of a liquid to the outer surfaces of a plurality of flat planar substrates, which comprises the steps of:

(a) suspending the substrates vertically from a carrier so that the substrates are aligned in a parallel row and are spaced a predetermined distance from each other;

(b) positioning a plurality of freely rotatable liquid applicator rollers having deformable liquid-absorbing contact surfaces in retracted positions away from substrate engaging positions;

(c) immersing the substrates into a bath of the coating liquid so as to wet the surfaces to be coated with the liquid;

(d) moving the plurality of freely rotatable liquid applicator rollers from the initially retracted positions into spaces between the substrates;

(e) positioning the rollers in substrate-engaging positions horizontally in the bath adjacent to the surface of the liquid, so that the rollers are partly in and partly out of the liquid, where the contact surfaces of the rollers compressively engage opposite surfaces of the substrates during withdrawal of the substrates from the bath in regions at least partly above the surface of the liquid of the bath; and

(f) withdrawing the substrates from the bath after the rollers have been positioned in substrate-engaging positions so that movement of the substrates causes synchronous rotation of the rollers and so that the contact surfaces of the rollers distribute uniform coatings of the liquid along the contacted surfaces of the substrate.

4. A method as recited in claim 3, wherein the contact surfaces of the rollers are comprised of chamois or synthetic chamois.

5. A method as recited in claim 3, wherein the rollers are immersed in the liquid with less than half of the liquid-absorbing surfaces of the rollers in contact with the liquid.