Method and apparatus for coating on baggy web

Patent metadata

Field	Value
Publication number	US-11465172-B2
Application number	US-201816763152-A
Country	US
Kind code	B2
Filing date	Nov 12, 2018
Priority date	Nov 21, 2017
Publication date	Oct 11, 2022
Grant date	Oct 11, 2022

Abstract

Methods and apparatuses for applying coatings on a baggy web are provided. A Mayer rod and a back-up roll engage with each other to form a nip. The back-up roll has a deformable inner layer with a surface thereof covered by a deformable outer layer. The Mayer rod and the flexible web at a contacting area are impressed into the back-up roll with a machine-direction nip width W and a nip engagement depth D, which enables formation of a coating having a substantially uniform thickness.

First claim

What is claimed is:

1. A method of applying a coating onto a baggy web, the method comprising:
contacting a Mayer rod with a back-up roll, wherein the back-up roll includes a deformable inner layer with a surface thereof covered by a deformable outer layer, the inner layer being softer than the outer layer, wherein the deformable inner layer of the back-up roll has a hardness less than 20 Shore A, and the deformable outer layer of the back-up roll has a hardness greater than about 40 Shore A;
disposing a flexible web between the back-up roll and the Mayer rod;
wrapping the flexible web around at least one of the back-up roll and the Mayer rod;
pressing the Mayer rod and the back-up roll against each other to form a nip therebetween, wherein the Mayer rod and the flexible web at a contacting area are impressed into the back-up roll with a machine-direction nip width W and a nip engagement depth D; and
providing a coating material upstream of the nip to form a coating on a surface of the web downstream of the nip,
wherein the back-up roll has a S-Factor, averaged over a range of the nip engagement D from about 0.05 mm to about 1 mm, being less than about 10 (10 6 ·N/m 5/2 ), where the S-Factor is defined by an equation

S
=

F

D
·

R
E

,

where S represents the S-Factor, D represents the nip engagement depth, F represents an applied force, and RE represents an effective radius of the Mayer rod and the back-up roll, and
wherein the Mayer rod comprises one or more predefined openings that remain open when the Mayer rod and the back-up roll are pressed against each other to allow the coating material to pass through.

2. The method of claim 1 , further comprising adjusting at least one of the machine-direction nip width W and the nip engagement depth D to adjust a wet thickness of the coating.

3. The method of claim 2 , wherein the machine-direction nip width W or the nip engagement depth D is adjusted by adjusting the relative distance between the respective axes of the Mayer rod and the back-up roll.

4. The method of claim 3 , wherein the relative distance is adjusted by moving, via a mounting and positioning mechanism, at least one of the Mayer rod and the back-up roll.

5. The method of claim 2 , wherein a wet thickness of the coating is adjusted to be within the range of about 5 to about 200 micrometers.

6. The method of claim 1 , wherein the Mayer rod is pressed via a mechanical holder mounted on opposite ends of the Mayer rod, without touching a coating surface of the Mayer rod.

7. The method of claim 6 , wherein the mechanical holder includes one or more bearing elements at the opposite ends of the Mayer rod.

8. The method of claim 1 , further comprising rotating the Mayer rod at a speed from about 1 m/min to about 50 m/min.

9. The method of claim 1 , wherein the flexible web is a baggy web having surface non-flatness characteristics including at least one of a lane, a strip, a bump, or a ripple.

10. 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, wherein the deformable inner layer of the back-up roll has a hardness less than 20 Shore A, and the deformable outer layer of the back-up roll has a hardness greater than about 40 Shore A;
a Mayer rod in contact with the back-up roll;
a flexible web disposed between the back-up roll and the Mayer rod, and wrapping around at least one of the back-up roll and the Mayer rod; and
one or more mechanical holders configured to press the Mayer rod and the back-up roll against each other to form a nip therebetween,
wherein the Mayer rod and the flexible web at a contacting area are impressed into the back-up roll with a machine-direction nip width W and a nip engagement depth D, and
wherein the back-up roll has a S-Factor, averaged over a range of the nip engagement D from about 0.05 mm to about 1 mm, being less than about 10 (10 6 ·N/m 5/2 ), where the S-Factor is defined by an equation

S
=

F

D
·

R
E

,

where S represents the S-Factor, D represents the nip engagement depth, F represents an applied force, and RE represents an effective radius of the Mayer rod and the back-up roll, and
wherein the Mayer rod comprises one or more predefined openings that remain open when the Mayer rod and the back-up roll are pressed against each other to allow the coating material to pass through.

11. The coating apparatus of claim 10 , wherein the one or more mechanical holders are attached to at least one of the Mayer rod and the back-up roll and are capable of moving at least one of the Mayer rod and the back-up roll.

12. The coating apparatus of claim 10 , wherein the one or more mechanical holders are connected to opposite ends of the Mayer rod without touching a coating surface of the Mayer rod.

13. The coating apparatus of claim 12 , wherein the one or more mechanical holders include one or more bearing elements at each end of the Mayer rod.

14. The coating apparatus of claim 13 , wherein the one or more mechanical holders further include a stiffening beam to support the bearings at the ends of Mayer rod.

15. The coating apparatus of claim 10 , wherein the one or more mechanical holders include a positioning mechanism to control the distance between the respective axes of the Mayer rod and the back-up roll to adjust at least one of the machine-direction nip width W and the nip engagement depth D.

16. The coating apparatus of claim 10 , wherein the deformable inner layer of the back-up roll has a hardness less than 10 Shore A.

17. The coating apparatus of claim 10 , wherein the inner layer of the back-up roll has a compressibility of less than about 45 psi at 25% deflection.

18. The coating apparatus of claim 10 , wherein the deformable outer layer of the back-up roll has a hardness greater than about 50 Shore A.

19. The coating apparatus of claim 10 , wherein the deformable outer layer includes one or more materials of an elastomer, a metal, a fabric, or a nonwoven.

20. The coating apparatus of claim 10 , wherein the deformable inner layer includes one or more materials of a synthetic foam, an elastomer, a fabric or nonwoven layer, or a soft rubber.

Assignees

• 3M Innovative Properties Co

Inventors

• Meyers Kara A
• Dodds Shawn C
• Vandre Eric A
• Rattray Tyler J
• Grove Kevin T
• Schiewer Brittni M
• Pekurovsky Mikhail L
• Javid Samad
• Dobbs James N
• Meredyk Wayne D

Classifications

• B05C1/0808

  Details thereof, e.g. surface characteristics · CPC title

• B05C1/0865

  the cooperating element being a roller, e.g. a coating roller · CPC title

• D21H23/58

  Details thereof, e.g. surface characteristics, peripheral speed · CPC title

• B05C1/083

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

• D21H23/56

  Rolls (D21H23/38 takes precedence) · CPC title