EP-4735256-A1 - MULTILAYER OPTICAL FILM

Abstract

A multilayer optical film includes a plurality of alternating first and second microlayers. The first microlayers comprise a first copolyester comprising naphthalene dicarboxylate and terephthalate units totaling greater than 92 mole percent based on total moles of dicarboxylate units. The second microlayers comprise a second copolyester comprising: terephthalate units at greater than 60 mole percent based on total moles of dicarboxylate units; isosorbide units at greater than 15 mole percent based on total moles of diol units; and at least one of ethylene-glycol units and cyclohexanedimethanol units at greater than 15 mole percent in total based on total moles of diol units. The optical film has a delamination resistance of no less than about 200 g/in under a 90 degree, 10 in/min peel test.

Inventors

• HUSEBY, Kevin T.
• JOHNSON, STEPHEN A.
• DERKS, KRISTOPHER J.
• HAAG, ADAM D.
• SOUSA, MATTHEW E.
• ACHARYA, BHARAT R.
• TAYLOR, ROBERT D.
• MINNO, Samuel A.
• BLACK, WILLIAM B.

Assignees

• 3M Innovative Properties Company

Dates

Publication Date

20260506

Application Date

20240620

Claims (15)

1. 1. A multilayer optical film comprising a plurality of polymeric layers comprising: at least one macrolayer, each macrolayer of the at least one macrolayer having an average thickness greater than about 600 nm; and a plurality of alternating first and second microlayers disposed on the at least one macrolayer and numbering at least 10 in total, each first and second microlayer having an average thickness less than about 500, the first microlayers comprising a first copolyester comprising naphthalene dicarboxylate and terephthalate units totaling greater than 92 mole percent based on total moles of dicarboxylate units, the second microlayers comprising a second copolyester comprising: terephthalate units at greater than 60 mole percent based on total moles of dicarboxylate units; isosorbide units at greater than 15 mole percent based on total moles of diol units; and at least one of ethylene-glycol units and cyclohexanedimethanol units at greater than 15 mole percent in total based on total moles of diol units, such that when the optical film is scored by cutting through at least some of the plurality of polymeric layers to result in a plurality of scored polymeric layers, then the scored optical film has a delamination resistance of no less than about 200 g/in under a 90 degree, 10 in/min peel test.
2. 2. The multilayer optical film of claim 1, wherein the second copolyester comprises isosorbide units at greater than 18 mole percent based on total moles of diol units.
3. 3. The multilayer optical film of claim 1, wherein the second copolyester comprises ethyleneglycol units at greater than 10 mole percent based on total moles of diol units.
4. 4. The multilayer optical film of claim 1, wherein the second copolyester comprises cyclohexanedimethanol units at greater than 20 mole percent based on total moles of diol units.
5. 5. The multilayer optical film of claim 1, wherein the second copolyester comprises terephthalate units at greater than 85 mole percent based on total moles of dicarboxylate units.
6. 6. The multilayer optical film of claim 1, wherein, based on total moles of dicarboxylate units, the first copolyester comprises greater than 80 mole percent naphthalene dicarboxylate units and greater than 2 mole percent terephthalate units.
7. 7. The multilayer optical film of claim 1, wherein the first copolyester comprises ethylene -glycol units at greater than 70 mole percent based on total moles of diol units.
8. 8. The multilayer optical film of claim 7, wherein the first copolyester comprises cyclohexanedimethanol units at greater than 1 mole percent based on total moles of diol units.
9. 9. The multilayer optical film of claim 1, wherein the first copolyester comprises terephthalate units at greater than 2 mole percent based on total moles of dicarboxylate units, and each of the first and second copolyesters comprises cyclohexanedimethanol units at greater than 1 mole percent based on total moles of diol units.
10. 10. A multilayer optical film comprising a plurality of polymeric layers comprising: at least one macrolayer, each macrolayer of the at least one macrolayer having an average thickness greater than about 600 nm; and a plurality of alternating first and second microlayers disposed on the at least one macrolayer and numbering at least 10 total, each first and second microlayer having an average thickness less than about 500 nm, the first microlayers comprising a first copolyester comprising a copolymerized blend of at least polyethylene naphthalate (PEN) at greater than 60 weight percent and polyethylene terephthalate (PET) at greater than 2 weight percent, the first copolyester comprising naphthalene dicarboxylate and terephthalate units totaling greater than 92 mole percent based on total moles of dicarboxylate units, the second microlayers comprising a second copolyester comprising: terephthalate units at greater than 35 weight percent; isosorbide units at greater than 8 weight percent; and at least one of ethylene-glycol units and cyclohexanedimethanol units at greater than 8 weight percent in total, such that when the optical film is scored by cutting through at least some of the plurality of polymeric layers to result in a plurality of scored polymeric layers, then the scored optical film has a delamination resistance of no less than about 200 g/in under a 90 degree, 10 in/min peel test.
11. 11. The multilayer optical film of claim 10, wherein the copolymerized blend of the first copolyester further comprises greater than 1 weight percent of glycol-modified polyethylene terephthalate (PETG).
12. 12. The multilayer optical film of claim 11, wherein the second copolyester comprises a copolymerized blend of at least poly(ethylene-glycol isosorbide cyclohexanedimethanol terephthalate) (PEICT) at greater than 60 weight percent and glycol- modified polyethylene terephthalate (PETG) at greater than 2 weight percent, the PEICT comprising isosorbide units at greater than 15 weight percent.
13. 13. A multilayer optical film comprising a plurality of polymeric layers comprising: at least one macrolayer, each macrolayer of the at least one macrolayer having an average thickness greater than about 600 nm; and a plurality of alternating first and second microlayers disposed on the at least one macrolayer and numbering at least 10 in total, each first and second microlayer having an average thickness less than about 500 nm, the first microlayers comprising a first copolyester comprising a copolymerized blend of at least polyethylene naphthalate (PEN) at greater than 60 weight percent, polyethylene terephthalate (PET) at greater than 2 weight percent, and glycol-modified polyethylene terephthalate (PETG) at greater than 1 weight percent, the second microlayers comprising a second copolyester comprising: terephthalate units at greater than 35 weight percent; isosorbide units at greater than 8 weight percent; ethylene-glycol units at greater than 1 weight percent; and cyclohexanedimethanol units at greater than 1 weight percent, such that when the optical film is scored by cutting through at least some of the plurality of polymeric layers to result in a plurality of scored polymeric layers, then the scored optical film has a delamination resistance of no less than about 200 g/in under a 90 degree, 10 in/min peel test.
14. 14. The multilayer optical film of any one of claims 1 to 13, wherein each of the first and second microlayers comprises the respective first and second copolymers at greater than 80 weight percent.
15. 15. The multilayer optical film of any one of claims 1 to 13, wherein the second microlayers comprise the second copolyester at greater than 40 weight percent and further comprises a polycarbonate blended with the second copolyester.

Description

MULTILAYER OPTICAL FILM TECHNICAL FIELD The present application generally relates to optical films, and more specifically, to multilayer optical films. BACKGROUND A multilayer optical film can include a plurality of polymeric interference layers for providing reflection for at least one polarization state in a desired wavelength range. SUMMARY In some aspects, the present description provides a multilayer optical film including a plurality of polymeric layers including at least one microlayer and a plurality of alternating first and second microlayers disposed on the at least one macrolayer. Each macrolayer of the at least one macrolayer can have an average thickness greater than about 600 nm. The plurality of alternating first and second microlayers number at least 10 in total. Each first and second microlayer has an average thickness less than about 500 nm. The first microlayers comprise a first copolyester comprising naphthalene dicarboxylate and terephthalate units totaling greater than 92 mole percent based on total moles of dicarboxylate units. The second microlayers comprise a second copolyester comprising: terephthalate units at greater than 60 mole percent based on total moles of dicarboxylate units; isosorbide units at greater than 15 mole percent based on total moles of diol units; and at least one of ethylene-glycol units and cyclohexanedimethanol units at greater than 15 mole percent in total based on total moles of diol units. The optical film can be such that when the optical film is scored by cutting through at least some of the plurality of polymeric layers to result in a plurality of scored polymeric layers, then the scored optical film has a delamination resistance of no less than about 200 g/in under a 90 degree, 10 in/min peel test. In some aspects, the present description provides a multilayer optical film including a plurality of polymeric layers including at least one microlayer and a plurality of alternating first and second microlayers disposed on the at least one macrolayer. Each macrolayer of the at least one macrolayer can have an average thickness greater than about 600 nm. The plurality of alternating first and second microlayers number at least 10 in total. Each first and second microlayer has an average thickness less than about 500 nm. The first microlayers comprise a first copolyester comprising a copolymerized blend of at least polyethylene naphthalate (PEN) at greater than 60 weight percent and polyethylene terephthalate (PET) at greater than 2 weight percent. The first copolyester can comprise naphthalene dicarboxylate and terephthalate units totaling greater than 92 mole percent based on total moles of dicarboxylate units. The second microlayers comprise a second copolyester comprising: terephthalate units at greater than 35 weight percent; isosorbide units at greater than 8 weight percent; and at least one of ethyleneglycol units and cyclohexanedimethanol units at greater than 8 weight percent in total. The optical fdm can be such that when the optical film is scored by cutting through at least some of the plurality of polymeric layers to result in a plurality of scored polymeric layers, then the scored optical film has a delamination resistance of no less than about 200 g/in under a 90 degree, 10 in/min peel test. In some aspects, the present description provides a multilayer optical film including a plurality of polymeric layers including at least one microlayer and a plurality of alternating first and second microlayers disposed on the at least one macrolayer. Each macrolayer of the at least one macrolayer can have an average thickness greater than about 600 nm. The plurality of alternating first and second microlayers number at least 10 in total. Each first and second microlayer has an average thickness less than about 500 nm. The first microlayers include a first copolyester comprising a copolymerized blend of at least polyethylene naphthalate (PEN) at greater than 60 weight percent, polyethylene terephthalate (PET) at greater than 2 weight percent, and glycol-modified polyethylene terephthalate (PETG) at greater than 1 weight percent. The second micro layers comprising a second copolyester comprising: terephthalate units at greater than 35 weight percent; isosorbide units at greater than 8 weight percent; ethylene-glycol units at greater than 1 weight percent; and cyclohexanedimethanol units at greater than 1 weight percent. The optical film can be such that when the optical film is scored by cutting through at least some of the plurality of polymeric layers to result in a plurality of scored polymeric layers, then the scored optical film has a delamination resistance of no less than about 200 g/in under a 90 degree, 10 in/min peel test. These and other aspects will be apparent from the following detailed description. In no event, however, should this brief summary be construed to limit the claimable subject matter. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is