Articles with binder-deficient slip coating and method for making same

• US 9,915,762 B2
• Filed: 08/20/2013
• Issued: 03/13/2018
• Est. Priority Date: 08/21/2012
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Derks, Kristopher J., Hagen, Jeffrey W., Lockridge, James E., Peterson, Jeffrey A., Hedding, Brent A.
• Primary Examiner(s): Wollschlager, Jeffrey
• Application Number:
  US14/422,911
• Publication Number:
  US 20150226883A1
• Time in Patent Office: 1,666 Days
• CPC Class Codes: B05D 1/265 Extrusion coatings
• CPC Class Codes: B05D 3/04 by exposure to gases
• CPC Class Codes: B05D 3/12 by mechanical means
• CPC Class Codes: B29K 2995/0072 Roughness, e.g. anti-slip
• CPC Class Codes: B29K 2995/0074 patterned, grained
• CPC Class Codes: B32B 2255/10 on synthetic resin layer or on natural or synthetic rubber layer
• CPC Class Codes: B32B 2255/26 Polymeric coating
• CPC Class Codes: B32B 2264/025 Acrylic resin particles, e.g. polymethyl methacrylate or ethylene-acrylate copolymers
• CPC Class Codes: B32B 2307/412 Transparent
• CPC Class Codes: B32B 2307/702 Amorphous
• CPC Class Codes: B32B 2307/746 Slipping, anti-blocking, low friction
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/20 using fillers, pigments, thixotroping agents
• CPC Class Codes: B32B 27/36 comprising polyesters
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: G02B 1/105 Protective coatings
• CPC Class Codes: G02B 1/12 by surface treatment, e.g. by irradiation
• CPC Class Codes: G02B 1/14 Protective coatings, e.g. hard coatings
• CPC Class Codes: Y10T 428/2495 Thickness [relative or absolute]
• CPC Class Codes: Y10T 428/24975 No layer or component greater than 5 mils thick

Abstract

A sheet comprising: (1) a core member comprising one or more layers and having a first major surface and (2) a slip control layer disposed on at least a portion of the first major surface, wherein the slip control layer comprises: (i) a footing layer disposed on at least a portion of the first major surface of the core member, (ii) a binder layer disposed on the footing layer, and (iii) an array of particles disposed in the binder layer and footing layer and protruding therefrom, wherein the average diameter of the particles is greater than the combined thickness of the foot layer and binder layer. A process for making such a sheet comprising: (1) providing a core member; (2) forming a footing layer on at least a portion of the first major surface of the core member, wherein the footing layer is viscoelastic and has a T_g that is lower than either the T_g or the T_m of the polymer at the first major surface of the core member; (3) applying a binder layer composition comprising a film forming polymer and particles to the surface of the footing layer; then (4) tentering the assembly under sufficient heat to soften the footing layer such that the particles sink into the footing layer, wherein the average diameter of the particles is greater than the combined thickness of the footing layer and binder layer.

Claims

1. A process for making a sheet comprising:

(1) providing a polymeric core member comprising one or more layers and having a first major surface;

(2) forming a footing layer on at least a portion of the first major surface, wherein the footing layer is viscoelastic and has a T_g that is lower than either the T_g or the T_m of the polymer at the first major surface of the core member;

(3) applying a binder layer composition comprising a film forming polymer and particles to the surface of the footing layer to yield an assembly;

then

(4) tentering the assembly under sufficient heat to soften the footing layer such that the particles sink into the footing layer, the footing layer, binder layer, and particles constituting a slip control layer, wherein the average diameter of the particles is greater than the combined thickness of the footing layer and binder layer such that the particles protrude from the surface of the slip control layer opposite the core member.

2. The process of claim 1 wherein the core member comprises multilayer optical film.

3. The process of claim 1 wherein the footing layer and core member are formed simultaneously via coextrusion.

4. The process of claim 1 wherein the footing layer is amorphous.

5. The process of claim 1 wherein the footing layer has a T_g of at least about 85°

C.

6. The process of claim 1 wherein the footing layer is from about 0.5 to about 3 microns thick.

7. The process of claim 1 wherein the binder layer composition comprises a film forming component, particles, and water.

8. The process of claim 1 wherein the binder layer composition is applied to the surface of the footing layer and self-levels.

9. The process of claim 1 wherein the binder layer composition is at least partially dried before tentering.

10. The process of claim 1 wherein the binder layer after tentering is from about 100 to about 500 nanometers thick.

11. The process of claim 1 wherein the binder layer composition further comprises one or more additives selected from the group consisting of leveling agents, fire retardants.

12. The process of claim 1 wherein the binder layer composition is dried to form a film with an array of the particles therein.

13. The process of claim 1 wherein a mean particle diameter of the particles is from about 2 to about 30 microns.

14. The process of claim 1 wherein some particles sink into the footing layer so far as to contact the first major surface of the core member.

15. The process of claim 1 further comprising arranging a plurality of the sheets in a stack wherein each sheet is arranged in substantially planar form.

16. The process of claim 1 further comprising winding the sheet upon itself into roll form.

17. The process of claim 16 wherein said winding is pack winding wherein the rolled sheet is pressed against a back up roller when wound upon a jumbo to reduce the amount of entrained air.