Use of a transport coating to apply a thin coated layer

Patent metadata

Field	Value
Publication number	US-9333533-B2
Application number	US-201113877342-A
Country	US
Kind code	B2
Filing date	Nov 21, 2011
Priority date	Nov 24, 2010
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

It has now been determined that a first coating layer may be applied to a substrate by a first coating die in a much thinner layer than its rheological properties and/or surface properties would normally allow. This is accomplished by using a second coating fluid dispensed from a second coating die acting as a “dynamic liquid squeegee” to transport, spread, even, or meter the first coating layer on the substrate by varying a gap between the second coating die and the substrate.

First claim

What is claimed is:

1. A method of coating a substrate comprising:
providing a first coating die having a first slot width;
providing a second coating die having a second slot width;
applying a first coating fluid from the first coating die onto a substrate forming a first coating layer;
applying a viscoelastic second coating fluid from the second coating die over the first coating layer on the substrate forming a second coating layer; and
varying a gap between the second coating die and the substrate to increase a width and reduce a thickness of the first coating layer on the substrate;
wherein the second slot width is greater than the first slot width, and wherein the gap is reduced until the width of the first coating layer is increased to substantially equal a width of the second coating layer.

2. A method according to claim 1 wherein the first and the second coating dies are combined in a single die body.

3. A method according to claim 2 wherein the substrate comprises a structured liner having at least one rib on a first major surface facing the first coating die.

4. A method according to claim 2 wherein the first coating layer comprises a channel and an average thickness of the first coating layer is less than a height of the channel.

5. A method according to claim 2 wherein the first coating fluid has a Newtonian flow characteristic.

6. The method of claim 2 wherein a third coating layer is applied over the second coating layer.

7. The method of claim 2 wherein the first coating layer comprises a dry first coating width, and the dry first coating width is at least 50% greater than the first slot width.

8. The method of claim 7 wherein the dry first coating width is at least 150% greater than the first slot width.

9. The method of claim 2 wherein the viscoelastic second coating fluid has a higher viscosity than the first coating fluid at the same shear rate.

10. The method of claim 2 wherein the viscoelastic second coating fluid comprises a shear thinning fluid having a lower viscosity at a higher shear rate.

11. A method according to claim 1 wherein the first and the second coating dies are each in a distinct die body dispensing onto the substrate at separated positions along the substrate's length.

12. A method according to claim 11 wherein the substrate comprises a structured liner having at least one rib on a first major surface facing the first coating die.

13. A method according to claim 11 wherein the first coating layer comprises a channel and an average thickness of the first coating layer is less than a height of the channel.

14. The method of claim 11 wherein a third coating layer is applied over the second coating layer.

15. The method of claim 11 wherein the first coating layer comprises a dry first coating width, and the dry first coating width is at least 50% greater than the first slot width.

16. The method of claim 15 wherein the dry first coating width is at least 150% greater than the first slot width.

17. The method of claim 11 wherein the viscoelastic second coating fluid has a higher viscosity than the first coating fluid at the same shear rate.

18. The method of claim 11 wherein the viscoelastic second coating fluid comprises a shear thinning fluid having a lower viscosity at a higher shear rate.

Assignees

• Dudley William R
• Kolb William Blake
• 3M Innovative Properties Co

Inventors

• Dudley William R
• Kolb William Blake

Classifications

• B05D7/52 Primary

  Two layers · CPC title

• B05D2252/02

  of indefinite length · CPC title

• B05D1/40

  Distributing applied liquids or other fluent materials by members moving relatively to surface · CPC title

• B05D7/54

  No clear coat specified · CPC title

• B05D1/26 Primary

  performed by applying the liquid or other fluent material from an outlet device in contact with, or almost in contact with, the surface · CPC title