METHODS FOR PREPARING FUNCTIONAL OPTICAL FILMS

Abstract

The disclosure provides post-production methods for functionalization of optical quality films produced by top tier manufactures. The methods disclosed herein allow for the incorporation of different additives into existing films.

Claims

1. A method for producing an optical article comprising a functionalized optical laminate comprising: (a) providing a film or laminate; (b) providing a functionalized adhesive comprising an adhesive component and at least one functional additive; (c) extruding the functionalized adhesive onto a film or laminate surface to form an adhesive-coated functionalized film or laminate; and (d) incorporating the adhesive-coated functionalized film or laminate into an optical article.

2. The method of claim 1, wherein the film or laminate comprises one or more optical polymer films.

3. The method of claim 1, further comprising the step of: laminating a second film or laminate onto the adhesive-coated film or laminate produced in step (c) to form a second functionalized laminate.

4. The method of claim 3, wherein the second film or laminate comprises one or more optical polymer films.

5. The method of claim 1, wherein the at least one functional additive comprises at least one of a dye, tint, pigment, and light filter.

6. The method of claim 1, wherein the adhesive component comprises a low-melt temperature cellulose resin.

7. The method of claim 1, wherein at least a portion of the at least one functional additive co-migrates into the film with the solvent and becomes embedded below the optical film or laminate surface.

8. The method of claim 1, wherein at least one surface of the film or laminate has a surface roughness value Ra that is less than 0.1 μm.

9. An optical article comprising a functionalized optical film prepared by: providing a first film having a smooth surface and an exposed surface opposite the smooth surface; providing a solution comprising a solvent, and a solute comprising at least one functional additive; applying the solution onto one of the smooth surface or the exposed surface of the first film to form a coated first film surface; and optionally, evaporating at least a portion of the solvent; wherein at least a portion of the solute is embedded below the first film surface.

10. The optical article of claim 9, wherein the smooth surface has a surface roughness value Ra that is less than 0.1 μm.

11. The optical article of claim 9, wherein the exposed surface of the first film is non-polished.

12. The optical article of claim 9, wherein the preparation of the functionalized optical film comprises incorporating the functionalized first film into an ophthalmic lens.

13. The optical article of claim 9, wherein at least a portion of the solute co-migrates into the film with the solvent and becomes embedded below the first film surface.

14. The optical article of claim 9, wherein said functional additive comprises at least one of a dye, tint, pigment, and light filter.

15. The optical article of claim 9, wherein the solution is a functionalized adhesive solution.

16. The optical article of claim 9, wherein the solution comprises a low-melt temperature cellulose resin.

17. An optical article comprising a functionalized optical laminate prepared by: providing a film or laminate; providing a functionalized adhesive comprising an adhesive component, and at least one functional additive; extruding the functionalized adhesive onto a film or laminate surface to form an adhesive-coated functionalized film or laminate; and incorporating the adhesive-coated functionalized film or laminate into an optical article.

18. The optical article of claim 17, wherein at least one surface of the film or laminate has a surface roughness value Ra that is less than 0.1 μm.

19. The optical article of claim 17, wherein said functional additive comprises at least one of a dye, tint, pigment, and light filter.

20. The optical article of claim 17, wherein said adhesive component comprises a low-melt temperature cellulose resin.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0024] FIG. 1 depicts a dual-film laminate whose TAC film layers are bonded by a functionalized adhesive solution. The dual-film laminate is subsequently incorporated into a polar health laminate by combining the dual-film laminate with a light polarizing film/TAC film laminate. The polar health laminate is then incorporated into a light polarizing lens. The term ‘polar’ is defined as any film or multi-film structure that will either absorb, transmit, scatter, or reflect incident light vibrations wholly or partially in a planar, circular, or eliptical direction. Known structures in the art include, but not limited to, iodine or dichroic dye containing stretched films, nano spaced wire grid film, and combinations of polarizing and anisotropic retarding films. The physics of polarized light is well understood by those ordinary skilled in the art.

[0025] FIG. 2 depicts a TAC film that has been coated with a functionalized coating solution. The resulting functionalized film is incorporated into a laminate, which is subsequently incorporated into a polar lens.

[0026] FIGS. 3A-B depict laminates produced by a solvent-free thermal bonding process. In FIG. 3A, a functionalized thermal adhesive composition (Ply 2) is applied onto a laminate comprising a polar PVA film (Ply 4) and a TAC film (Ply 5). In FIG. 3B, the functionalized thermal adhesive composition (Ply 2) is applied onto a TAC film base layer (Ply 1). A second TAC film layer (Ply 3) is then applied onto the adhesive to produce a dual-TAC film laminate.

[0027] FIG. 4 depicts a solvent casting process for applying a functionalized solution to a film or laminate whereby a functionalized solution is coated onto a carrier support film then transferred to a film or laminate.

DETAILED DESCRIPTION

[0028] Various features and advantageous details are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. It should be understood, however, that the detailed description and the specific examples, while indicating embodiments, are given by way of illustration only, and not by way of limitation. Various substitutions, modifications, additions, and/or rearrangements will be apparent to those of ordinary skill in the art from this disclosure.

[0029] In the following description, numerous specific details are provided to provide a thorough understanding of the disclosed embodiments. One of ordinary skill in the relevant art will recognize, however, that the invention may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

[0030] An objective of the present disclosure is to provide high-quality, functionalized ophthalmic films by incorporating one or more additives into mass-produced, high optical quality display films. The functionalized films may be incorporated into ophthalmic and plano lenses. A variety of different additives may be incorporated into the films, including light filters, tints, and other additives. The additives may be incorporated into existing films by co-migration with a solvent below the film's surface or by dispersion into extrudable resins. The methods disclosed herein employ high-quality films mass-produced by top tier film manufacturers as substrates and use semi-synthetic methods to produce high-quality functionalized optical films.

[0031] The vast majority of high quality optical films that are produced by solvent-casting methods are intended for display markets. By contrast, optical films manufactured for niche markets, e.g., ophthalmic and plano lenses, are produced on a smaller scale. Films produced by incorporating dyes, tints, or other additives into the dope solution are more costly and typically lower in quality as compared to mass-produced optical films used in the display industry. The methods disclosed herein employ mass-produced, high optical quality display films as scaffolds for incorporating the desired additives in shorter, limited quantity production runs.

[0032] High optical quality display films have two distinct film surfaces. The smoother surface is formed by contact with a highly-polished belt surface that transfers its smooth finish to the film surface during solvent casting. The opposite film surface is formed by exposure to the evacuation atmosphere and solvent evaporation.

[0033] The following examples employ cellulose-ester resin films (e.g., triacetate cellulose, TAC) as examples, but any optical film known to those of skill in the art may be employed. Films can include polycarbonate-, acrylic-, nylon-, cellulose-based films, optical films made from (co)polymers or polymer blends used in the photographic film and digital display device industry including but not limited to polyamide (nylon), polyvinyl alcohol, cyclic olefin (co)polymers, aliphatic polyesters (e.g., polylactide), polycaprolactone, polyetherimide, polystyreneor, and other optical films known to those of skill in the art. The term “DYE” as used below encompasses any functional additive, including but not limited to dyes, ultraviolet light absorbers, retardation regulators, stabilizers, antioxidants, tints, pigment, light filter, and other specialty additives for incorporation into a film or laminate. The star annotation (e.g., TAC*, DAC*) denotes a resin (triacetate cellulose, diacetate cellulose, or any other resin type) that was used either in solution, as a melt, or any incorporable form that is not a film. Some examples below employ an additional polar polyvinyl alcohol (PVA) film to impart polarity on the laminate and finished lens, but any other suitable functional film, including but not limited to an optical absorber, a filter, a clear spacer, or a reflector may be used. A polar PVA film is polyvinyl alcohol based light polarizer in which a polyvinyl alcohol film containing one or more dichroic dyes and/or iodine/iodide dyes was stretched during the manufacturing process to impart light polarizing properties on the film.

EXAMPLES

Example 1: Functionalized Films by Film Solvent Bonding

[0034] An adhesive solution comprising a functional additive and a solvent is used to bond two films. The adhesive solution may further comprise a resin. The resulting laminate may be incorporated into an optical article, or may be used to build larger laminates, which in turn may be incorporated into an optical article.

[0035] In the exemplary laminate depicted in FIG. 1, a TAC film is employed as the base layer (Ply 1). An adhesive solution comprising a functional additive (DYE), a resin (TAC*), and a solvent is prepared and applied as Ply 2 to the TAC film base layer (Ply 1). The adhesive solution is preferably applied to the non-polished surface of TAC film Ply 1. At least a portion of the adhesive solution solvent may be evaporated. A second TAC film is then applied as Ply 3 to the adhesive layer. The non-polished surface of TAC film Ply 2 is preferably contacted with the adhesive layer to produce a laminate with polished surfaces facing outward. Using the above notations, the resulting laminate is of the form TAC/DYE+TAC*/TAC.

[0036] In an alternative embodiment, an adhesive solution consisting of a functional additive (DYE) and a solvent is prepared. The adhesive solution does not include a resin. The adhesive solution is applied to the non-polished surface of TAC film Ply 1. At least a portion of the adhesive solution solvent may be evaporated. A second TAC film is then applied as Ply 3 to the adhesive layer. The films' non-polished surfaces are preferably in contact with the adhesive solution. The resulting laminate is of the form TAC/DYE/TAC.

[0037] Either of the functionalized three-ply laminates created above (TAC/DYE+TAC*/TAC or TAC/DYE/TAC) may be incorporated into larger laminates. In the exemplary embodiment depicted in FIG. 1, a polar PVA film is laminated onto the three-ply laminate. A subsequent TAC film is then laminated onto the polar PVA film. Either or both of the subsequently-applied layers may be incorporated as described above. That is, an adhesive solution comprising comprising a functional additive, a solvent, and optionally a resin may be used to incorporate a functional additive into one or more of the subsequently-applied layers. In other embodiments, either or both of the subsequently-applied layers may be incorporated without a functional additive.

[0038] Either of the functionalized laminates described above may be incorporated into an optical article using methods known to those of skill in the art. In some embodiments, a film or laminate is inserted into a casting mold, a resin is added in front and/or behind film or laminate, and the resin is cured using increased temperature, ultraviolet light, e-beam, or a different energy source, or by allowing the resin to self-cure with the passage of time. In further embodiments, a film or laminate is inserted into an injection mold cavity and a resin is injected in front and/or behind the film or laminate. The resin may then be cured using the methods discussed above. In some aspects, a laminate can be used as a lens without having gone through a convention casting or injection molding process, and can be thermoformed and/or surface ground int an optical article. In further aspects, an adhesive may be applied to a film or laminate, followed by forming the film or laminate into a curved wafer which may then be adhered to the surface of a lens.

Example 2: Functional Films by Solution Coating

[0039] A coating solution comprising a functional additive and a solvent is used to coat and at least partially embeb the additive into a film layer. The coating solution may further comprise a binder.

[0040] A coating solution comprising a functional additive (DYE) a resin (TAC*), and a solvent is prepared. The coating solution is applied onto a film. At least a portion of the coating solution solvent may be evaporated. In the example depicted in FIG. 2, the film is a TAC film (Ply 1, TAC base layer). The coating solution (Ply 2) is preferably applied onto the non-polished surface of the film. The resulting coated film is of the form TAC/DYE+TAC*.

[0041] In an alternative embodiment, a coating solution comprising a functional additive (DYE) and a solvent is prepared and applied onto a film. The coating solution is preferably applied onto the non-polished surface of the film. At least a portion of the coating solution solvent may be evaporated. The resulting coated film is of the form TAC/DYE.

[0042] Either of the functionalized films created above (TAC/DYE+TAC* or TAC/DYE) may be incorporated into larger laminates. In the exemplary embodiment depicted in FIG. 2, a polar PVA film (Ply 2) is laminated onto the functionalized film. A subsequent TAC film (Ply 3) is then laminated onto the polar PVA film. Either or both of the subsequently-applied layers may be incorporated as described above. That is, an adhesive solution comprising a functional additive, a solvent, and optionally a resin may be used to coat and at least partially embed a functional additive into one or more of the subsequently-applied layers. In other embodiments, either or both of the subsequently-applied layers may be incorporated without a functional additive.

[0043] Either of the functionalized films or laminates described above may be incorporated into a lens using methods known to those of skill in the art, including but not limited to injection molding and thermoset casting.

Example 3: Functional Film by Solventless Film Thermal Bonding

[0044] A solventless thermal adhesive composition comprising a resin and at least one functional additive is applied onto a film. The film+adhesive composition may be incorporated into a laminate.

[0045] A functionalized thermal adhesive composition comprising a resin (DAC*) and at least one functional additive (DYE) is prepared. The resin may be a low melt temperature cellulose ester resin, e.g., mono-/di-substituted cellulose acetate butyrate.

[0046] The functionalized thermal adhesive composition is applied onto a laminate. In the embodiment depicted in FIG. 3A, the functionalized thermal adhesive composition (Ply 2) is applied onto a laminate comprising a polar PVA film (Ply 4) and a TAC film (Ply 5). The functionalized thermal adhesive composition is applied to the polar PVA film of the PVA/TAC laminate, however, the adhesive may be applied to the TAC film of the laminate. The resulting laminate is of the form DYE+DAC*/PVA-Polar/TAC. The exposed DYE+DAC* layer may be used to thermally bond the laminate to another film or laminate.

[0047] In the alternative embodiment depicted in FIG. 3B, the functionalized thermal adhesive composition is applied onto a base film by melt extrusion. The functionalized thermal adhesive composition (Ply 2) is applied onto a TAC film base layer (Ply 1). The thickness of the TAC film base layer is preferably <80 μm. A second TAC film (Ply 3) is applied and thermally bonded onto the adhesive layer to produce a TAC/DYE+DAC*/TAC laminate. The thickness of the second TAC film is preferably <80 μm.

[0048] Either of the laminates may be incorporated into a larger laminate and may optionally be incorporated into a lens using methods known to those of skill in the art, including injection molding and thermoset casting.

Example 4: Functional Film by Casting on a Carrier Support Film

[0049] A functionalized solution comprising a functional additive, a resin, and a solvent is cast onto a carrier support film then transferred to a film or laminate.

[0050] A functionalized solution comprising a functional additive (DYE), a resin (TAC*), and a solvent is prepared. In the embodiment depicted in FIG. 4, the solution (Ply 1) is coated onto a carrier support film (Ply 0). The carrier support film may be foil, polycarbonate (PC), polyethylene terephthalate (PET), or other support films known those of skill in the art, and preferably includes a polish-finished release surface. The functionalized solution is preferably cast onto the polish-finished surface of the carrier support film.

[0051] At least a portion of the functionalized solution solvent is evaporated and the resulting stand-alone film is then transferred to a film or laminate. In the embodiment depicted in FIG. 4, the stand-alone film (Dye Functional TAC*) is transferred to a PVA/TAC laminate. The carrier support film is then separated to produce a functionalized film or laminate. The functionalized film or laminate prepared by the method described above may be incorporated into a larger laminate, or incorporated into a lens using methods known to those of skill in the art, including injection molding, thermoset casting, or by adhesion to other films.

[0052] The claims are not to be interpreted as including means-plus- or step-plus-function limitations, unless such a limitation is explicitly recited in a given claim using the phrase(s) “means for” or “step for,” respectively.