Acrylic polyvinyl acetal film for a light directing article

Patent metadata

Field	Value
Publication number	US-11397286-B2
Application number	US-201716307875-A
Country	US
Kind code	B2
Filing date	Jun 5, 2017
Priority date	Jun 7, 2016
Publication date	Jul 26, 2022
Grant date	Jul 26, 2022

Abstract

A light directing article comprises an acrylic polyvinyl acetal film to protect the optical elements of the light directing article. The acrylic polyvinyl acetal film has a Tg of at least 30° C. and comprises a (meth)acrylic polymer and polyvinyl acetal polymer. The acrylic polyvinyl acetal film is flexible and durable to mechanical deformation.

First claim

What is claimed is:

1. A light directing article comprising:
a body layer having a Tg of at least 30° C. but no greater than 60° C. comprising a (meth)acrylic polymer and polyvinyl acetal polymer comprising polymerized units having the following formula

wherein R 1 is hydrogen or a C1-C7 alkyl group; and
a second layer proximate the body layer, wherein the second layer comprises optical elements.

2. The light directing article of claim 1 , wherein the body layer has a tensile elastic modulus of at least 1 MPa at 25° C. and 1 hertz.

3. The light directing article of claim 1 , wherein the body layer comprises at least 20, 25, 30, 35, 40, 50 wt-% of polymerized units of monofunctional alkyl (meth)acrylate monomer having a Tg of less than 0° C.

4. The light directing article of claim 1 , wherein the body layer comprises no greater than 85 wt-% of polymerized units of monofunctional alkyl (meth)acrylate monomer having a Tg of less than 0° C.

5. The light directing article of claim 3 , wherein the polymerized units of monofunctional alkyl (meth)acrylate monomer has a Tg of less than −10° C., −20° C., −30° C., −40° C., or −50° C.

6. The light directing article of claim 1 , wherein the body layer comprises polymerized units of an alkyl (meth)acrylate monomer having an alkyl group with eight carbon atoms.

7. The light directing article of claim 1 , wherein body layer comprises 5 to 30 wt-% of polyvinyl acetal polymer.

8. The light directing article of claim 1 , wherein the optical elements comprise beads or microstructured elements.

9. The light directing article of claim 8 , wherein the microstructured elements are longitudinally extending prisms or cube-corner elements.

10. The light directing article of claim 9 , wherein the cube-corner elements comprise truncated cubes or full cubes.

11. The light directing article of claim 1 , wherein the body layer is integrally connected with the second layer.

12. The light directing article of claim 11 , wherein the body layer is thermally bonded to the second layer.

13. The light directing article of claim 11 , wherein the body layer is adhesively bonded to the second layer.

14. The light directing article of claim 1 , wherein the light directing article is a roll of sheeting having a width bound by edges of the roll.

15. The light directing article of claim 1 , further comprising a specular reflective coating adjacent to or on the optical elements.

16. The light directing article of claim 1 , further comprising a seal film bonded to portions of the optical elements.

17. The light directing article of claim 1 , further comprising: an adhesive layer comprising a first region and a second region, wherein the second region surrounds the first region and is in contact with the optical elements and wherein the first region and second region have different properties to form a low refractive index layer between the adhesive layer and the optical elements.

18. The light directing article of claim 1 , further comprising an adhesive layer on the second layer, opposite the body layer.

19. The light directing article of claim 1 , wherein the light directing article is a retroreflective sheeting.

Assignees

• 3M Innovative Properties Co

Inventors

• Jones Todd D
• Thakkar Bimal V
• Fansler Duane D
• Schultz Anthony F
• Janoski Jonathan E
• Lueneburg David C
• Thomas Carla S
• Whiting Tien Yi T H
• Watkins Robert F

Classifications

• B32B7/12

  using interposed adhesives or interposed materials with bonding properties · CPC title

• C08L33/064

  containing anhydride, COOH or COOM groups, with M being metal or onium-cation · CPC title

• B29D11/00615

  moulded by partially embedding reflective elements, e.g. glass beads, into the surface of a support, e.g. to make prefabricated road markings (dispensing reflective beads on road markings in situ E01C23/163) · CPC title

• B32B5/16

  characterised by features of a layer formed of particles, e.g. chips, powder {or granules (layer formed of natural mineral particles B32B19/00; layer being formed of wood fibres, chips or particles B32B21/02)} · CPC title

• B32B2307/418

  Refractive · CPC title