Acrylic polyvinyl acetal films and composition

Patent metadata

Field	Value
Publication number	US-11629250-B2
Application number	US-202016952159-A
Country	US
Kind code	B2
Filing date	Nov 19, 2020
Priority date	Dec 8, 2014
Publication date	Apr 18, 2023
Grant date	Apr 18, 2023

Abstract

A film is described comprising a (meth)acrylic polymer and a polyvinyl acetal (e.g. butyral) resin. In some embodiments, the film has a glass transition temperature (i.e. Tg) ranging from 30° C. to 60° C. In some embodiments, the film has a gel content of at least 20% or greater. In some embodiments, the film has an elongation at break of at least 175%. The film typically comprises photoinitiator as a result of the method by which the film was made. The film may be a monolithic film or a layer of a multilayer film.

First claim

What is claimed is:

1. A film comprising:
(meth)acrylic polymer comprising polymerized units of polar monomer and polyvinyl acetal resin comprising polymerized units having the following formula

wherein R 1 is hydrogen or a C1-C7 alkyl group;
wherein the film has a single Tg ranging from 30° C. to 60° C. and a gel content of at least 20%.

2. The film of claim 1 wherein the film comprises at least 10 wt-% of polymerized units of monofunctional alkyl (meth)acrylate monomer having a Tg of less than 0° C.

3. The film of claim 2 wherein the film comprises no greater than 60 wt-% of polymerized units of monofunctional alkyl (meth)acrylate monomer having a Tg of less than 0° C.

4. The film of claim 2 or 3 wherein the monofunctional alkyl (meth)acrylate monomer has a Tg of less than −10° C.

5. The film of claim 1 wherein the film comprises polymerized units of an alkyl (meth)acrylate monomer having an alkyl group with 8 carbon atoms.

6. The film of claim 1 wherein the film further comprises up to 35 wt-% of polymerized units of a monofunctional alkyl (meth)acrylate monomer having a Tg greater than 40° C.

7. The film of claim 1 wherein the film comprises at least 10 wt-% and no greater than 65 wt-% of polymerized units of polar monomers.

8. The film of claim 7 wherein polar monomers are selected from acid-functional, hydroxyl functional monomers, nitrogen-containing monomers, and combinations thereof.

9. The film of claim 1 wherein the film comprises polyvinyl butyral.

10. The film of claim 1 wherein the film comprises 5 to 30 wt-% of polyvinyl acetal resin.

11. The film of claim 1 wherein the polyvinyl acetal resin has a glass transition temperature ranging from 60° C. to 75° C.

12. The film of claim 1 wherein the polyvinyl acetal resin has an average molecular weight (Mw) ranging from 20,000 g/mole to 75,000 g/mole.

13. The film of claim 1 wherein the film further comprises polymerized units of a multifunctional crosslinker wherein the crosslinker comprises functional groups selected from (meth)acrylate, alkenyl, and hydroxyl-reactive groups.

14. The film of claim 1 wherein the film further comprises additives including inorganic filler in an amount no greater than 25 wt-%.

15. The film composition of claim 1 wherein the film comprises photoinitiator.

16. The film composition of claim 1 wherein the film comprises no greater than 10 wt-% of polymerized units of methacrylate monomers.

17. The film composition of claim 1 wherein the (meth)acrylic polymer is a random copolymer.

18. The film of claim 1 wherein the film is a monolithic film or a film layer of a multilayer film.

19. The film of claim 18 wherein the multilayer film further comprises a second film layer, the second film layer comprising a (meth)acrylic polymer and polyvinyl acetal resin wherein the second film layer has a Tg of less than 30° C.

20. The film of claim 1 wherein the film has an elongation at break of at least 175%.

Assignees

• 3M Innovative Properties Company

Inventors

• Janoski Jonathan E
• Schultz Anthony F
• Lyon Keith R
• Steelman Ronald S
• Lewandowski Kevin M
• Lipscomb Corinne E
• Hobbs Terry R
• Weikel Arlin L
• Seth Jayshree
• Fansler Duane D
• Abe Hidetoshi

Classifications

• B32B27/306

  comprising vinyl acetate or vinyl alcohol (co)polymers · CPC title

• C08J5/18 Primary

  Manufacture of films or sheets · CPC title

• B32B2250/246

  All polymers belonging to those covered by groups B32B27/32 and B32B27/30 · CPC title

• C08J2333/08

  Homopolymers or copolymers of acrylic acid esters · CPC title

• B32B27/308

  comprising acrylic (co)polymers · CPC title