Patent Description:
A functional film and/or a photochromic film is used to add protection or various optical properties to an optical lens. Due to its soft texture, each side of the functional film and/or photochromic film is usually laminated with an optical thermoplastic film using an adhesive. The produced polymeric laminate is subsequently incorporated on a surface of an optical lens. To insure the integrity of the laminate on a curved surface of the optical lens, the adhesion between the thermoplastic films of the laminate has to be sufficient to avoid peeling or delamination of the laminate during further lens applications.

Conventionally, there are several types of adhesives used to make a photochromic or functional film containing laminates. For instance, commercially available adhesives such as ultra violet (UV) curable acrylic based adhesive (e.g., Optoclear® <NUM> from Onbitt Co. ) and polyurethane based adhesive (ADCOTE® L76-<NUM> from Dow Chem Co. ) have been used to bond the photochromic film or functional film to the thermoplastic films in the laminates. However, many of these commercially available adhesives are organic solvent-based adhesives that have high environmental impact. A solvent-less two-part polyurethane adhesive can be used to produce the laminate, but the two components of the adhesive have to be mixed and immediately used due to a very short pot life for this type of adhesive. Additionally, addition of catalysts are generally required to shorten the curing duration of the two-part adhesives. Thus, overall it is relatively complex to handle the solvent-less two-part polyurethane adhesive during preparation of the polymeric laminate. UV curable adhesives are another type of most commonly used adhesives. However, UV curable adhesives often have negative impact on the color performance of the laminate due to prolonged exposure to UV light during the curing process. Other newly designed adhesives, such as a glyoxal adhesive system in <CIT>, tri-layered adhesive system disclosed in <CIT> or polyvinyl alcohol-based resin adhesive disclosed in <CIT>, have been used for making the polymeric laminates. However, these new adhesives do not have strong adhesion to either the photochromic or functional film, or the polycarbonate or cellulose triacetate based thermoplastic films, resulting in unstable laminates.

Overall, while adhesives and methods exist for preparing a photochromic or functional film-containing laminate, the need for improvements in this field persists in light of at least the aforementioned drawbacks with the conventional adhesives and methods.

<CIT> discloses a method for manufacturing a polarizing structure, comprising the following steps: providing a PVA-based polarizing film; providing a protective film on at least one face of the polarizing film; deposing an adhesion primer structure on at least one face of said protective film oriented towards said polarizing film; deposing a water based polymer adhesive solution, preferably a PVOH-based adhesive solution, or a glyoxal-based adhesive solution between said polarizing film and said protective film; pressing the protective film against the polarizing film to form a polarizing structure; and curing the assembly at a temperature between <NUM> - <NUM> for <NUM>-<NUM>. Plasma, corona or UV treatment, or chemical surface modification are used to improve interlaminar adhesion.

A solution to the above-mentioned problems associated with methods of preparing a photochromic film or functional film-containing laminate has been discovered. The solution resides in a method of preparing the photochromic laminate that includes pre-treating the photochromic film or functional film and applying a water-based adhesive between the photochromic or functional film and the second thermoplastic film. By way of example, the front and back surfaces of the photochromic or functional film can be pre-treated by corona treatment before the water-based adhesive is applied. The corona treatment can enable the water-based adhesive to form strong adhesion with both the photochromic or functional film and the second thermoplastic film. Thus, this method is capable of producing strong photochromic or functional film-containing laminates for optical lenses. Furthermore, the use of water-based adhesives can lower the environmental impact compared to using organic-solvent based adhesives in the laminates. Moreover, water-based adhesive does not require complex handling procedures during the preparation of the laminates compared to the two-part adhesives. Therefore, the methods of the present invention provide a technical achievement over at least some of the problems associated with the currently available adhesives and methods of preparing photochromic or functional film containing laminates.

Some embodiments of the present invention are directed to a method of preparing a laminate as defined in appended claim <NUM>.

In some aspects, the treating can comprise applying to the first thermoplastic film a treatment that includes isopropyl alcohol (IPA) treatment, corona treatment, plasma treatment, flame treatment, solid CO<NUM> spray treatment, laser cleaning or ablation treatment, soft media treatment, or combinations thereof. In some aspects, the laminate has an adhesion between the first thermoplastic film and the second thermoplastic film in a range of <NUM> to <NUM> N/inch and all ranges and values there between including <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, and <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, and <NUM> to <NUM> N/inch. In some aspects, the corona treatment may have a treatment duration longer than about <NUM> seconds. In some aspects, the plasma treatment may have a treatment duration longer than about <NUM> seconds. In some aspects, the treatment duration for corona treatment may be in a range of <NUM> to <NUM> seconds and all ranges and values there between including ranges of <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, and <NUM> to <NUM> seconds. In some aspects, the treatment duration for plasma treatment may be in a range of <NUM> to <NUM> seconds and all ranges and values there between including ranges of <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, and <NUM> to <NUM> seconds.

The first thermoplastic film comprises a functional film and/or a photochromic film containing a photochromic dye, a dichroic dye, a blue cut dye, an infra-red cut dye, a UV cut dye, a selective wavelength cut dye, a color enhancement dye, a light filter dye, or combinations thereof. In embodiments of the invention, the second thermoplastic film may comprise polycarbonate (PC), cellulose triacetate (TAC), polymethyl methacrylate, polyamide, polyethylene terephthalate, cyclic olefin copolymer, or combinations thereof. The laminating is carried out using a roll-to-roll process. The roll-to-roll process includes a heating temperature of <NUM> to <NUM> and all ranges and values there between including ranges of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM>. The roll-to-roll process includes a heating duration of <NUM> to <NUM> minutes and all ranges and values there between including ranges of <NUM> to <NUM> minutes, <NUM> to <NUM> minutes, <NUM> to <NUM> minutes, <NUM> to <NUM> minutes, and <NUM> to <NUM> minutes. The heating in the roll-to-roll process is adapted to cure the water-based adhesive. In some embodiments, the obtained laminate may be further post-cured or annealed at a temperature in a range of <NUM> to <NUM> for up to <NUM> hours after the roll-to-roll process.

The water-based adhesive comprises a water-based polyvinyl alcohol (PVOH) adhesive, a water-based hot melt adhesive (HMA), a water-based polyurethane latex adhesive, and combinations thereof. In some embodiments, the water-based adhesive may further include a crosslinking agent. Non-limiting examples of the crosslinking agent may include HCl, glyoxal, aldehyde, hemiacetal compounds, acetoacetal group-containing resin or polymers, (e.g., Safelink® SPM-<NUM>, The Nippon Synthetic Chemical Industry Co. , Japan), amine, metal salts, hydrazide, or combinations thereof. In some embodiments, the treating of the front surface and/or the back surface of the first thermoplastic film may enable the formation of hydrogen bonds at an interface between the first thermoplastic film and the second thermoplastic film.

Some embodiments of the present invention are directed to a photochromic laminate. The photochromic laminate comprises a first thermoplastic film comprising a pre-treated front surface and a pre-treated back surface, as well as a water-based adhesive layer laminated on each of the pre-treated front surface and the pre-treated back surface of the first thermoplastic film. The photochromic laminate comprises a second thermoplastic film laminated on each of the water-based adhesive layers. Each of the water-based adhesive layers may have a thickness of <NUM> to <NUM> and all ranges and values there between including ranges of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM>. In some aspects, the second thermoplastic may comprise polycarbonate, cellulose triacetate, polymethyl methacrylate, polyamide, polyethylene terephthalate, or combinations thereof. The water-based adhesive layer comprises a water-based polyvinyl alcohol (PVOH) adhesive, a water-based hot melt adhesive (HMA), a water-based polyurethane (PU) latex adhesive, or combinations thereof. In some aspects, the water-based adhesive layer may contain <NUM> to <NUM> wt. % water and <NUM> to <NUM> wt. % solid content.

Some embodiments of the present invention are directed to a method of preparing a laminate. The method may comprise applying corona and/or plasma treatment to a front surface and a back surface of a first thermoplastic film to produce a treated front surface and a treated back surface. The method may comprise laminating a second thermoplastic film on the treated front surface and the treated back surface of the first thermoplastic film using a water-based adhesive to form hydrogen bonds at an interface between the first thermoplastic film and the second thermoplastic film.

Some embodiments of the present invention are directed to a method of improving bond strength of a water-based adhesive between a first thermoplastic film comprising a polyurethane and/or polyether block amide and a second thermoplastic film.

The terms "wt. %," or "mol. %" refers to a weight, volume, or molar percentage of a component, respectively, based on the total weight, the total volume, or the total moles of material that includes the component.

The terms "inhibiting" or "reducing" or "preventing" or "avoiding" or any variation of these terms, when used in the claims and/or the specification, includes any measurable decrease or complete inhibition to achieve a desired result.

Other objects, features and advantages of the present invention will become apparent from the following figures, detailed description, and examples. It should be understood, however, that the figures, detailed description, and examples, while indicating specific embodiments of the invention, are given by way of illustration only and are not meant to be limiting. Additionally, it is contemplated that changes and modifications within the scope of the invention will become apparent to those skilled in the art from this detailed description. In further embodiments, features from specific embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any of the other embodiments. In further embodiments, additional features may be added to the specific embodiments described herein.

The currently available methods and/or adhesives used for making a laminate that comprises a thermoplastic film laminated on each side of a photochromic or functional film suffer the deficiencies including weak bonding strength between the adhesive and the thermoplastic films, high environmental impacts due to organic solvent used in the adhesives, and complex handling procedures for multi-part adhesives. The present invention provides a solution to these problems. The solution is premised on a method of preparing a photochromic film or functional film-containing laminate that comprises pre-treating the front and back surface of the photochromic film or functional film and using a water-based adhesive to bond a second thermoplastic film to the treated surface of the photochromic film or functional film. The pre-treatment is capable of enabling the water-based adhesive to form strong bond with both the photochromic film or functional film and the second thermoplastic films. Therefore, the adhesive overcomes the weak bond strength in the laminates occurring in the laminates prepared by conventional methods. Additionally, the water-based adhesive used in the method of the present invention is easy to handle compared to two-part solvent-less adhesives. The water-based adhesive can reduce environmental impact of the organic solvent based adhesives used in the conventional methods.

These and other non-limiting aspects of the present invention are discussed in further detail in the following sections.

Functional films and/or photochromic films can be incorporated to add extra optical properties to an optical lens. Due to the soft texture of the photochromic films or the functional films, a thermoplastic film, such as a polycarbonate film or cellulose triacetate film, is often laminated to both the front surface and the back surface of the photochromic film or functional film to form a laminate. The laminate can be subsequently incorporated on the surface of an optical lens.

Conventionally, the laminate comprising a functional film is prepared by using a commercially available adhesives including organic solvent based adhesive, UV curable adhesive, two-part polyurethane adhesive etc. These commercial available adhesives suffer various drawbacks including high environmental impact, negative impact on the color performance of the laminate, complex handling procedure, and/or low bonding strength between the adhesive(s) and the second thermoplastic films (e.g., polycarbonate and cellulose triacetate).

The method of the present invention can produce a laminate that uses a water-based adhesive and has a strong adhesion between the adhesive and the thermoplastic layers. As shown in <FIG>, embodiments of the present invention include method <NUM> of preparing a laminate that is incorporable to a surface of an optical lens. In embodiments of the invention, the optical lens may include polycarbonate, poly methyl methacrylate, polystyrene, polystyrene maleic anhydride, polyamide, thermoplastic urethane, thermoset polyurethane, polyester, copolyesters, polysulfone, cyclic olefin copolymers, polyphenyl oxide, allyl diglycol carbonate, polythiourethane, episulfur polymers, epoxy, poly(meth)acrylates, polythiomethacrylates, or combinations thereof.

In embodiments of the invention, as shown in block <NUM>, method <NUM> may comprise providing a first thermoplastic film comprising a front surface and a back surface. In some aspects, the first thermoplastic film may include a thermoplastic polyurethane film. The first thermoplastic polyurethane film may include polyurethane and/or polyether block amide. The first thermoplastic film comprises a functional film and/or a photochromic film. The functional film and/or photochromic film may contain a photochromic dye, a dichroic dye, a blue cut dye, an infra-red cut dye, a UV cut dye, a selective wavelength cut dye, a color enhancement dye, a light filter dye, or combinations thereof. In some aspects, the functional film or photochromic film may have a thickness in a range of <NUM> to <NUM> and all ranges and values there between including ranges of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM>.

As shown in block <NUM>, method <NUM> further comprises treating the front surface and the back surface of the first thermoplastic film. In some aspects, the treating at block <NUM> comprises applying a treatment to the front surface and the back surface first thermoplastic film. The treatment may include isopropyl alcohol (IPA) treatment, corona treatment, plasma treatment, flame treatment, solid CO<NUM> spray treatment, laser cleaning or ablation treatment, soft media treatment, or combinations thereof.

In some embodiments, the treatment may include corona treatment. The corona treatment may have a duration of more than <NUM> seconds. In some instances, the duration of the corona treatment may be in a range of <NUM> to <NUM> seconds and all ranges and values there between including ranges of <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, and <NUM> to <NUM> seconds. In some instances, a distance between treated front surface or treated back surface and a corona head may be in a range of <NUM> to <NUM> and all ranges and values there between including ranges of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM>. In some embodiments, the treatment may include plasma treatment and the plasma treatment may have duration of more than <NUM> seconds. In some instances, the duration of the plasma treatment may be in a range of <NUM> to <NUM> seconds and all ranges and values there between including ranges of <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, <NUM> to <NUM> seconds, and <NUM> to <NUM> seconds. In some instances, the plasma treatment may include vacuum plasma treatment and/or atmospheric plasma treatment.

In some instances, the treating at block <NUM> may include applying the isopropyl alcohol (IPA) treatment the front surface and back surface of the first thermoplastic film, and applying corona treatment and/or plasma treatment to the IPA treated front surface and/or back surface. In some instances, the treating at block <NUM> may include only IPA treatment. The applying of the isopropyl alcohol treatment may include wiping or dipping the front surface and/or back surface of the first plastic film with isopropyl alcohol. In some embodiments of the invention, method <NUM> further includes laminating a second thermoplastic film on the threated front surface and the treated back surface of the first thermoplastic film using a water-based adhesive to produce the laminate, as shown in block <NUM>. Laminating at block <NUM> is carried out using a roll-to-roll process. The roll-to-roll process includes heating during the laminating process. The heating is adapted to cure the water-based adhesive. The heating is carried out at a heating temperature of <NUM> to <NUM> and all ranges and values there between including ranges of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM>. The heating has a heating duration of <NUM> to <NUM> minutes and all ranges and values there between including ranges of <NUM> to <NUM> minutes, <NUM> to <NUM> minutes, <NUM> to <NUM> minutes, <NUM> to <NUM> minutes, and <NUM> to <NUM> minutes.

In some aspects, the roll-to-roll process may have a roller distance of <NUM> to <NUM> and all ranges and values there between including ranges of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM>. In some instances, the roll-to-roll process may be carried out at a laminating pressure of <NUM> to <NUM> psi and all ranges and values there between including ranges of <NUM> to <NUM> psi, <NUM> to <NUM> psi, <NUM> to <NUM> psi, <NUM> to <NUM> psi, <NUM> to <NUM> psi, <NUM> to <NUM> psi, <NUM> to <NUM> psi, <NUM> to <NUM> psi, <NUM> to <NUM> psi, <NUM> to <NUM> psi, <NUM> to <NUM> psi, <NUM> to <NUM> psi, <NUM> to <NUM> psi, <NUM> to <NUM> psi, and <NUM> to <NUM> psi. In some instances, the laminate obtained from the roll-to-roll process may be further cured or annealed at a temperature in a ranges of <NUM> to <NUM> for up to <NUM> hours.

In some embodiments, the second thermoplastic film may comprise polycarbonate, cellulose triacetate, polymethyl methacrylate, polyamide, polyethylene terephthalate, cyclic olefin copolymer, or combinations thereof. In some aspects, the second thermoplastic film may be optically clear. The second thermoplastic film may have a haze value of <NUM>% to <NUM>% and all ranges and values there between including ranges of <NUM> to <NUM>%, <NUM> to <NUM> %, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, <NUM> to <NUM>%, and <NUM> to <NUM>%. In some instances, the second thermoplastic films on the front surface and the back surface of the first thermoplastic films may be different thermoplastic films or substantially the same thermoplastic films. The water-based adhesive comprises a water-based polyvinyl alcohol (PVOH) adhesive, a water-based hot melt adhesive (HMA), a water based polyurethane (PU) latex adhesive, or combinations thereof. In some aspects, the water-based adhesive may further include a crosslinking agent. Non-limiting examples of the crosslinking agent may include HCl, glyoxal, aldehyde, hemiacetal compounds, acetoacetal group-containing resin or polymers (e.g., Safelink® SPM-<NUM>, The Nippon Synthetic Industry Co, Japan), amine, metal salts, hydrazide, , or combinations thereof. In some instances, the water-based adhesive contains <NUM> to <NUM> wt. % water and all ranges and values there between including ranges of <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, and <NUM> to <NUM> wt. The water-based adhesive further contain <NUM> to <NUM> wt. % solid content and all ranges and values there between including <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, and <NUM> to <NUM> wt. In some embodiments, the laminate has an adhesion (peel force) between the first thermoplastic film and the second thermoplastic film greater than <NUM> N/inch. In some instances, the adhesion between the first thermoplastic film and the second thermoplastic film in the laminate may be in a range of <NUM> to <NUM> N/inch and all ranges and values there between including <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, and <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, and <NUM> to <NUM> N/inch, <NUM> to <NUM> N/inch, and <NUM> to <NUM> N/inch.

In embodiments of the invention, during the laminating at block <NUM>, the treating of the front surface and the back surface of the first thermoplastic film at block <NUM> may enable the formation of the hydrogen bonds at an interface between the first thermoplastic film and the second thermoplastic film, resulting in improved adhesion between the first plastic film and the second plastic film compared to laminates produced using conventional methods. In some instances, the formation of the hydrogen bonds may be facilitated by heating during the laminating at block <NUM>. In some aspects, as shown in <FIG>, when the first thermoplastic film is treated by corona, oxygen concentration on the treated surface of the first thermoplastic film may increase, thereby facilitating the formation of hydrogen bonds with the water-based adhesive and/or the second thermoplastic film during laminating of block <NUM>. In some instances, an oxygen concentration of the treated front surface and/or treated back surface may be higher than <NUM> wt. % such that the adhesion between the first thermoplastic film and the second thermoplastic film is greater than <NUM> N/inch. In some aspects, during the laminating at block <NUM>, the treated front surface and back surface of the first thermoplastic film and the water-based adhesive may produce a chemical compound that improves adhesion between the first plastic film and the second plastic film compared to laminates produced using conventional methods.

Embodiments of the invention include a photochromic laminate for an optical lens. In some embodiments, the photochromic laminate may be prepared by method <NUM> as described above. In embodiments of the invention, the photochromic laminate may include a first thermoplastic film comprising a pre-treated front surface and a pre-treated back surface. The first thermoplastic polyurethane film includes polyurethane and/or polyether block amide. The first thermoplastic film includes a photochromic film containing a photochromic dye, a dichroic dye, a blue cut dye, an infra-red cut dye, a UV cut dye, a selective wavelength cut dye, a color enhancement dye, a light filter dye, or combinations thereof. In some embodiments, the front surface and the back surface of the first thermoplastic film may be pre-treated according to the treating step at block <NUM> as shown in <FIG>. The pre-treating may include isopropyl alcohol (IPA) treatment, corona treatment, plasma treatment, flame treatment, solid CO<NUM> spray treatment, laser cleaning or ablation treatment, soft media treatment, or combinations thereof.

The photochromic laminate further includes a water-based adhesive layer laminated on each of the pre-treated front surface and the pre-treated back surface of the first thermoplastic film. The water based adhesive layer comprises a water-based adhesive used in method <NUM> including a water-based polyvinyl alcohol (PVOH) adhesive, a water-based hot melt adhesive (HMA), a water based polyurethane (PU) latex adhesive, or combinations thereof. The water-based adhesive layer may further include crosslinking agent that include HCl, glyoxal, aldehyde, hemiacetal compounds, acetoacetal group-containing resin or polymers (e.g., Safelink® SPM-<NUM>, The Nippon Synthetic Chemical Industry Co. , Japan), amine, metal salts, hydrazide, or combinations thereof. In some instances, the water-based adhesive contains <NUM> to <NUM> wt. % water and all ranges and values there between including ranges of <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, and <NUM> to <NUM> wt. The water-based adhesive may contain <NUM> to <NUM> wt. % solid content and all ranges and values there between including <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, and <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, <NUM> to <NUM> wt. %, and <NUM> to <NUM> wt. In some aspects, the water in the water-based adhesive may be evaporated during the laminating step at block <NUM> in method <NUM>. In some aspects, the water-based adhesive may have a thickness of <NUM> to <NUM> and all ranges and values there between including <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM>.

The photochromic laminate further includes a second thermoplastic film laminated on each of the water-based adhesive layers. In some aspects, the second thermoplastic film may include polycarbonate, cellulose triacetate, polymethyl methacrylate, polyamide, polyethylene terephthalate cyclic olefin copolymer, or combinations thereof. In some instances, the second thermoplastic film may be laminated according to the laminating step at block <NUM> of method <NUM>. In some aspects, the second thermoplastic films laminated on the front surface and the back surface of the first thermoplastic film may each individually comprise polycarbonate, cellulose triacetate, polymethyl methacrylate, polyamide, polyethylene terephthalate, cyclic olefin copolymer, or combinations thereof. Therefore, the second thermoplastic films laminated on the front surface and the back surface of the first thermoplastic film may be different thermoplastic films or the substantially the same thermoplastic films.

As part of the disclosure of the present invention, specific examples are included below. The examples are for illustrative purposes only and are not intended to limit the invention. Those of ordinary skill in the art will readily recognize parameters that can be changed or modified to yield essentially the same results.

A photochromic film was produced using a commercial thermoplastic polyurethane (TPU) resin (Tecoflex® 80A from Lubrizol®) with a photochromic dye. The photochromic film was then cleaned by IPA and treated by corona treatment using a 3DT™ corona apparatus (Model: MultiDyne <NUM>, the United States) for about <NUM> seconds on each side. After the corona treatment, a polycarbonate (PC) film was laminated on each side of the photochromic film using a water-based hot-melt adhesive (HMA) (UD-<NUM> from Bond Polymers International Co, <NUM>% water diluted) in a roll lamination process at <NUM> psi roll pressure and a heating temperature of <NUM> for <NUM>. After heating, a strong adhesion between PC and TPU film was obtained. The peel force of the laminate was measured by Mark-<NUM>™ peel force equipment.

A PC-TPU-PC laminate was prepared using the same procedure as described in Example <NUM> except that the water-based adhesive in Example <NUM> was a water-based polyvinyl alcohol (PVOH). The water-based adhesive included <NUM> wt. % PVOH (Z-<NUM>, Nippon Gohsei) and about <NUM> wt. The peel force of the laminate was measured by Mark-<NUM>™ peel force equipment.

The laminate was prepared using the same procedure as Example <NUM> except that a commercial cellulose triacetate (TAC) film instead of a polycarbonate film was laminated on each side of the TPU film using the same water-based PVOH adhesive of Example <NUM> to form a TAC-TPU-TAC laminate. The peel force of the laminate was measured by Mark-<NUM>™ peel force equipment.

The laminate was prepared using the same procedure as Example <NUM> except that the adhesive used in Example <NUM> was a water-based latex adhesive (A-<NUM> of Essilor made by a water based polyurethane dispersion latex W234 from Witcobond Inc. The peel force of the laminate was measured by Mark-<NUM>™ peel force equipment.

A polyether block amide (PEBA) photochromic film was cleaned using a detergent soap and was then corona treated using 3DT™ corona (MultiDyne <NUM>) for about <NUM> seconds on each side thereof. A polycarbonate film was laminated on each side of the photochromic film using a water-based hot-melt adhesive (HMA) (UD-<NUM> from Bond Polymers International Co, <NUM>% water diluted) in a roll lamination process with a <NUM> psi roll pressure and a heating temperature of <NUM> for <NUM> minutes. The peel force of the laminate was measured by Mark-<NUM> peel force equipment.

A laminate was prepared using the same procedure as Example <NUM> except the TPU photochromic film was replaced by a polarizing poly vinyl alcohol (PVA) film. The produced PC-PVA-PC laminate showed low adhesion as the peel force for the laminate was less than <NUM> N/inch and the PC film could be peeled off easily by hand.

A laminate was prepared using the same procedure as Example <NUM> except that the water-based hot-melt adhesive in Example <NUM> was replace by a UV curable adhesive. The adhesive was cured by exposure to Xenon UV lamp for <NUM> seconds on each side thereof. The produced PC-TPU-PC laminate showed low adhesion level between films as the peel force for the laminate was less than <NUM> N/inch and the PC film could be peeled off easily by hand.

A PC-TPU-PC laminate was prepared using the same procedure as Example <NUM> except that the TPU film in Example <NUM> was not treated with corona treatment. The produced PC-TPU-PC laminate showed poor adhesion as the peel force for the laminate was less than <NUM> N/inch and the PC film could be peeled off easily by hand.

A PC-PC laminate was prepared using the same procedure as Example <NUM> except that the TPU film in Example <NUM> was replaced by a PC film. The produced PC-PC laminate showed poor adhesion as the peel force for the laminate was less than <NUM> N/inch and the PC film could be peeled off easily by hand.

The adhesion between the layers of the laminates obtained from Examples <NUM>-<NUM> were compared. The results are shown in Table <NUM>. As shown in Table <NUM>, the laminates produced in Examples <NUM>-<NUM> all had high adhesion level with the peel forces of at least <NUM> N/inch. For the laminates produced in all comparative examples (Examples <NUM>-<NUM>), the adhesion levels between each layers were lower than <NUM> N/inch. The results indicate that the corona treatment on the thermoplastic polyurethane (TPU) film can significantly improve the adhesion between polycarbonate and the water-based adhesive. The results further indicate that the corona treatment does not improve the adhesion when the adhesive is not a water-based adhesive. Furthermore, corona treatment on the polycarbonate films or the PVA films does not improve the adhesion between the films of the laminates.

A commercial TPU resin (Tecoflex® 80A from Lubrizol®) was extruded with photochromic dye to produce a photochromic TPU film having a thickness of about <NUM>. The photochromic TPU film was optically clear and transparent with a haze value about <NUM>%. The obtained film has good photochromic performance in terms of fading speed and darkness. The t<NUM>/<NUM> of the fading speed was about <NUM> seconds (measured by BMP equipment).

The obtained photochromic TPU film was pre-treated by corona treatment using a <NUM>-DT™ corona equipment for about <NUM> minute. The pre-treated photochromic TPU film was then laminated with PC films on each side thereof using <NUM> wt. % water diluted water-based hot-melt adhesive (UD-<NUM> from Bond Polymers Inc. The laminate was made in a lab roll lamination process with a roll pressure of <NUM> psi. Heating was applied in the lamination process at a temperature of <NUM> for <NUM>. After lamination, the PC-TPU-PC laminate showed strong adhesion and substantially the same photochromic performance as the TPU photochromic film (t1/<NUM> of the fading speed was about <NUM> seconds).

Claim 1:
A method of preparing a photochromic laminate, the method comprising:
providing a first thermoplastic film t, wherein the first thermoplastic film includes a front surface and a back surface;
treating the front surface and the back surface of the first thermoplastic film; and
laminating a second thermoplastic film on the treated front surface and on the treated back surface of the first thermoplastic film using a water-based adhesive to produce the laminate,
characterized in that
- said first thermoplastic film is a functional film and/or a photochromic comprising polyurethane and/or polyether block amide,
- said water-based adhesive comprises a water-based polyvinyl alcohol (PVOH) adhesive, a water-based hot melt adhesive (HMA), a water-based polyurethane (PU) latex adhesive, or combinations thereof, and
- wherein the laminating is carried out using a roll-to-roll process wherein the roll-to-roll process includes a heating temperature of <NUM> to <NUM> and a heating duration of <NUM> to <NUM> minutes to cure the water-based adhesive, and optionally further curing or annealing the laminate at a temperature in a range of <NUM> to <NUM> for up to <NUM> hours.