Method and apparatus of slot die coating over deformable back-up roll

Patent metadata

Field	Value
Publication number	US-2022016670-A1
Application number	US-201917309602-A
Country	US
Kind code	A1
Filing date	Dec 3, 2019
Priority date	Dec 13, 2018
Publication date	Jan 20, 2022
Grant date	—

Abstract

Methods and apparatuses for applying coatings (9) on a moving web (3) are provided. A slot die (20) and a back-up roll (11) engage with each other. The back-up roll has a deformable inner layer (12) with a surface thereof covered by a deformable outer layer (14). The slot die and the flexible web at a contacting area are impressed into the back-up roll with an engagement depth D, which enables formation of a coating having a substantially uniform thickness.

First claim

1 . A method of applying a coating onto a web, the method comprising:
providing a back-up roll having a deformable inner layer with a surface thereof covered by a deformable outer layer, the inner layer being softer than the outer layer; providing a slot die having one or more die lips extending along a cross direction, the one or more die lips being positioned proximate to the back-up roll; disposing a flexible web between the back-up roll and the one or more die lips; dispensing a liquid coating material from the slot die onto the flexible web, wherein the flexible web at a contacting area is impressed into the back-up roll with an engagement depth D.

2 . The method of claim 1 , further comprising adjusting the engagement depth D in a range from about one micrometer to about 2 mm.

3 . The method of claim 1 , further comprising metering a liquid flow through the slot die to control a wet thickness of the coating.

4 . The method of claim 3 , wherein the wet thickness of the coating is adjusted to be within the range of about 1 to about 500 micrometers.

5 . The method of claim 1 , further comprising pressing the slot die against the back-up roll.

6 . The method of claim 1 , wherein the flexible web has one or more surface non-flatness characteristics.

7 . The method of claim 6 , wherein the flexible web is a baggy web.

8 . The method of claim 6 , wherein the one or more surface non-flatness characteristics includes a splice, a web thickness variation, or a web wrinkle.

9 . The method of claim 1 , further comprising wrapping the flexible web around the back-up roll.

10 . The method of claim 1 , wherein the back-up roll has an S-Factor, averaged over a range of the engagement D from about 0.05 mm to about 1 mm, optionally being less than about 15 (10 6 ·N/m 5/2 ).

11 . A coating apparatus comprising:
a back-up roll having a deformable inner layer with a surface thereof covered by a deformable outer layer, the inner layer being softer than the outer layer; a slot die having one or more die lips extending along a cross direction, the one or more die lips being positioned proximate to the back-up roll; and a flexible web disposed between the back-up roll and the slot die, wherein the flexible web at a contacting area is impressed into the back-up roll with an engagement depth D, and the slot die is configured to dispense a liquid coating material onto the web.

12 . The coating apparatus of claim 11 , wherein the deformable inner layer of the back-up roll has a hardness less than 20 Shore A.

13 . The coating apparatus of claim 11 , wherein the inner layer of the back-up roll has a compressibility of less than about 45 psi at 25% deflection.

14 . The coating apparatus of claim 11 , wherein the deformable outer layer of the back-up roll has a hardness greater than about 40 Shore A.

15 . The coating apparatus of claim 11 , wherein the deformable outer layer includes one or more materials of an elastomer, a metal, a fabric, or a nonwoven.

16 . The coating apparatus of claim 11 , wherein the deformable inner layer includes one or more materials of a synthetic foam, an engraved, structured, 3D printed, or embossed elastomer, a fabric or nonwoven layer, a plurality of cavities filled with gas of a controlled pressure, or a soft rubber.

17 . The coating apparatus of claim 11 , wherein the back-up roll has an S-Factor, averaged over a range of the engagement D from about 0.05 mm to about 1 mm, being less than about 10 (10 6 ·N/m 5/2 ).

18 . The coating method of claim 1 , wherein the liquid coating material has a viscosity lower than about 10,000 centipoise (cps).

19 . The coating method of claim 1 , wherein the deformable outer layer has a hardness greater than about 40 Shore A.

20 . The coating method of claim 1 , wherein the deformable inner layer has a hardness less than about 20 Shore A.

Assignees

• 3M Innovative Properties Co

Inventors

• Dodds Shawn C
• Rattray Tyler J
• Meyers Kara A
• Pekurovsky Mikhail L
• Ciliske Scott L
• Dobbs James N
• Javid Samad

Classifications

• B29C48/35

  with rollers · CPC title

• B05C5/027

  Coating heads with several outlets, e.g. aligned transversally to the moving direction of a web to be coated (B05C5/0254 takes precedence) · CPC title

• B05C5/0258

  flow controlled, e.g. by a valve (B05C5/0262, B05C5/0266 take precedence) · CPC title

• B05C1/083

  being passed between the coating roller and one or more backing rollers · CPC title

• B05C5/0254 Primary

  Coating heads with slot-shaped outlet (B05C5/0283 takes precedence) · CPC title