Acrylic polyvinyl acetal films, composition, and heat bondable articles

Patent metadata

Field	Value
Publication number	US-10619019-B2
Application number	US-201515533398-A
Country	US
Kind code	B2
Filing date	Dec 7, 2015
Priority date	Dec 8, 2014
Publication date	Apr 14, 2020
Grant date	Apr 14, 2020

Abstract

A film is described comprises a (meth)acrylic polymer and a polyvinyl acetal (e.g. butyral) resin. The film has a tensile elastic modulus of at least 1 MPa at 25° C. and 1 hertz and a glass transition temperature (i.e. Tg) less than 30 C. The film typically comprises photoinitiator as a result of the method by which the film was made. In one embodiment, the film is heat bondable and further comprising a backing.

First claim

What is claimed is:

1. A film comprising:
(meth)acrylic polymer and 5 to 20 wt. % 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 tensile elastic modulus of at least 1 MPa at 25 C and 1 hertz and a Tg less than 30° C.

2. The film of claim 1 wherein the film comprises at least 25 wt-% and no greater than 85 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 monofunctional alkyl (meth)acrylate monomer has a Tg of less than −10° C.

4. The film of claim 1 wherein the film comprises a bio-based content of at least 25% of the total carbon content.

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 20 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 further comprises at least 5 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 polyvinyl acetal resin has a polyvinyl alcohol content ranging from 10 to 30 wt-%.

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 polyacetal resin has an average molecular weight (Mw) ranging from 10,000 g/mole to 100,000 g/mole.

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

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

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

19. The film of claim 1 wherein the film is a film layer of a multilayer film.

20. The film of claim 1 wherein the film exhibits a single Tg as measured by Differential Scanning calorimetry.

21. The film of claim 1 wherein the film is heat bondable at a temperature from 50 to 150° C.

Assignees

• 3M Innovative Properties Co

Inventors

• Lipscomb Corinne E
• Caruso Dailey Mary M
• Janoski Jonathan E
• Schultz Anthony F

Classifications

• B32B27/308

  comprising acrylic (co)polymers · CPC title

• C08J2429/14

  Homopolymers or copolymers of acetals or ketals obtained by polymerisation of unsaturated acetals or ketals or by after-treatment of polymers of unsaturated alcohols · CPC title

• C08J2333/08

  Homopolymers or copolymers of acrylic acid esters · CPC title

• C08L2203/16

  used for films · CPC title

• B32B27/08

  of synthetic resin · CPC title