CA2833843A1 - Switchable articles and methods of making same - Google Patents

Abstract

Provided is a switchable article, comprising: a transparent plastic layer; a switchable film; and optionally a heat-attenuating layer. The switchable film comprises a switching material disposed between a first and a second substantially transparent substrates, each substrate having disposed thereon a transparent conductive layer, the transparent conductive layers each in contact with the switching material. The switching material comprising one or more compounds may have electrochromic and photochromic properties. Further provided is a method of preparing a switchable glazing, comprising the steps of providing a switchable film;
optionally disposing a heat attenuating layer on a side of the switchable film; and molding a transparent plastic layer in contact with the heat attenuating layer

Description

SWITCHABLE ARTICLES AND METHODS OF MAKING SAME
TECHNICAL FIELD
[0001] The present disclosure relates to switchable articles, and methods of making switchable articles.
BACKGROUND

[0002] Glass is an excellent material for transparent articles such as architectural and vehicle glazings, lenses, opthalmic devices and the like, but brings with it several drawbacks in terms of weight and a potential cause of significant injury in the case of impact or breakage. Introduction of tempered and laminated glass has had a positive impact on the safety aspect of using glass, but the issue of weight remains. As vehicle components are redesigned to reduce weight (in an effort to reduce fuel consumption, cost and improve safety), plastic glazing becomes attractive.
Similarly, use of plastic visors and lenses, in masks, helmets, goggles and other eyewear reduces weight, and may allow for greater variety in shape and configuration, as plastics can be more readily molded.

[0003] Many plastics and polymers that provide the desired transparency for use in vehicle and automotive glazings are challenged by degradation and instability over time (yellowing), and the ease of surface marking by abrasion incurred with normal use. Various UV
blocking and abrasion resistant coating systems have been developed to overcome these disadvantages. Such plastics may be colored or tinted, or have colored layers applied to them (in part to disguise the yellowing and make abrasions less apparent), but these static layers do not provide a user with the ability to adjust the transmitted light.

[0004] Some electrochromic materials ("light valves" e.g. suspended particle devices US
7361252) may be suitable for preparing as a flexible film or layer, but may not tolerate temperatures necessary for thermoforming or injection molding (US 7361252).
Other electrochromic materials may be tolerant of elevated temperatures, but their manufacture may not be amenable to application to a flexible film or moldable surface. Some electrochromic materials applied to a glass layer (e.g. those of SAGE Electrochromics) may employ specialized coating processes such as sputtering or chemical vapor deposition, and the fine layers formed in this manner may be cracked or disrupted when molded or shaped.
SUMMARY

[0005] In accordance with one aspect, there is provided a switchable article, comprising: a transparent plastic layer; a switchable film; and optionally, a heat-attenuating layer. The switchable article may be prepared by any suitable method including thermoforming, vacuum forming, injection molding or the like.

[0006] In accordance with another aspect, there is provided an injection-molded switchable article comprising a transparent plastic layer, a switchable film and an adhesive layer.

[0007] In accordance with another aspect, there is provided a thermoformed, switchable article, comprising a transparent plastic layer and a switchable film. The thermoformed switchable article may further comprise an adhesive layer.

[0008] In accordance with another aspect, there is provided a method of preparing a switchable article comprising: providing a switchable film; optionally, disposing a heat attenuating layer on a side of the switchable film; and molding a transparent plastic layer in contact with the heat attenuating layer. The step of molding may be preceded by a step of placing the switchable film in an injection mold, with the heat attenuation layer facing the interior of the injection mold.

[0009] The switchable film may comprise a switching material disposed between a first and a second substantially transparent substrates, each substrate having disposed thereon a transparent conductive layer, the transparent conductive layers each in contact with the switching material.
The switching material may comprise one or more compounds having electrochromic and photochromic properties.

[0010] In accordance with another aspect, the switchable article is an architectural glazing, a vehicle glazing, or an opthalmic device such as a lens, visor, goggle, etc.

[0011] In accordance with another aspect, the switchable article is a vehicle glazing.

[0012] In accordance with another aspect, there is provided an article as described herein, with reference to the Figures.

[0013] This summary does not necessarily describe the entire scope of all aspects. Other aspects, features and advantages will become apparent to those of ordinary skill in the art upon review of the following description of specific embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS

[0014] These and other features will become more apparent from the following description.

[0015] Figure 1 shows a top view of a switchable article according to an embodiment.

[0016] Figure 2 shows a cross-sectional schematic diagram of a switchable article along line Y-Y.

[0017] Figure 3 shows a flowchart of steps of a method for producing a switchable article, according to an embodiment.

[0018] Figure 4a shows a cross sectional schematic diagram of a portion of a switchable article in a mold, according to an embodiment.

[0019] Figure 4b shows a cross sectional schematic diagram of a switchable article in a mold, according to an embodiment.

[0020] Figure 5 shows a schematic diagram of electrical leads and a controller of a switchable article, according to an embodiment.

[0021] Figure 6 shows a top view schematic of a switchable film, according to an embodiment.

[0022] Figure 7 shows a cross-sectional diagram of the switchable film, along line Z-Z.
DETAILED DESCRIPTION

[0023] The disclosure provides, in part, a switchable article, comprising: a transparent plastic layer; a switchable film; and optionally a heat-attenuating layer. The disclosure further provide, in part, a method of preparing a switchable article comprising: providing a switchable film;
optionally disposing a heat attenuating layer on a side of the switchable film; and molding a transparent plastic layer in contact with the heat attenuating layer. A
switchable article may be an architectural or vehicle glazing, lens, goggle, visor, or other transparent or partially transparent article where it is desired to alter the transmitted light.

[0024] Switchable glazing may be incorporated into vehicles (automobiles, trains, planes, water-going vessels or the like) or architectural installations (buildings, houses or the like). A
switchable glazing may be configured for appropriate size and location for mounting in a vehicle as a 'sunroof' or window (rear, side, windshield etc). The glazing may be transparent, or substantially, with or without tinting or coloration. The glazing may be opaque, or substantially opaque, as desired. The vehicle or architectural installation may further include a controller, or components for accessing a controller, to control the degree of transparency or opacity of the glazing, as may be desired. The controller may be controlled by a user, or controlled in an automated manner (e.g. in response to the environment or pre-programmed criteria), or a combination of the two. The glazing may have markings or decorations on a portion of the area.
While some embodiments may refer to a glazing, it will be apparent that the methods and properties addressed may be applicable to other switchable articles.

[0025] Inclusion of a UV blocking component in the switchable article may enhance weathering performance of the article, and may be protective of the interior of the vehicle or building where the article is installed by reducing the amount, and wavelength range, of UV
light that reaches the interior. Inclusion of an infrared (IR) blocking component in the switchable article may be useful in controlling the temperature of the article (dependent in part on the positioning of the infrared blocking component in the article layers), and may also be useful in reducing the heat gain of the interior of the vehicle or building where the article is installed by reducing the amount of infrared radiation reaching the interior. Where the infrared blocking component is positioned behind the switchable film (relative to the incident light), the article may accumulate heat, which may serve to increase the temperature of the switchable film.

[0026] Referring to Figure 1, a view of a switchable glazing according to one embodiment is shown generally at 20. The glazing 22 is substantially transparent with electrical lead 24 (comprising leads 142 and 144) connecting the switchable film of the glazing to the poles of a power source (not shown), via a controller 26. In the embodiment shown, the glazing may have a solid circumferential band 30 with an adjacent, patterned band 28 adjacent, around the periphery of the glazing. The bands may be applied with ink to the glazing during manufacture, or after the glazing is constructed.

[0027] Referring to Figure 2, a cross sectional schematic diagram of a switchable glazing according to one embodiment is shown generally at 10. A heat-attenuating layer 12 is disposed between a switchable film 14, and a transparent plastic layer 16, providing a switchable glazing having exposed sides A and B. Side A, side B or both sides A and B may further have applied thereto one or more layers comprising a coating system. The coating system may comprise one or more of an abrasion resistant layer, a weathering protective layer or the like, and may further include a primer layer.

[0028] Switchable film [0029] . A switchable film comprises a first and a second substrate, a first and a second electrode disposed on the surface of at least one of the substrates and a switching material disposed between first and second substrates and in contact with the switching material. The switching material may comprise one or more compounds having electrochromic and photochromic properties. The switchable film may be capable of transitioning from a light state to a dark state on exposure to UV radiation and from a dark state to alight state with exposure to visible light, or application of an electric voltage.

[0030] Examples of switchable films ("optical filter") are described in W02010/142019, and methods of constructing a switchable film are also addressed generally herein.
Substrates may be colorless or colored, transparent or reflective. The color may be selected to be complementary to that of the switching material in a dark state, light state or dark state and light state, and/or complementary to the color of the site where the switchable article is or will be used, or installed. For example, the switchable film may be of a color complementary to a vehicle or building envelope, frame of an opthalmic device or helmet or mask.

[0031] Substrates: A substrate may be glass or plastic ("organic glass") -float glass, tempered glass, toughened, or chemically -strengthened glass, an organic glass or the like. A substrate may be flexible (e.g. plastic film, glass film, or glass microsheet) or rigid.
An organic glass is an amorphous, solid glasslike material made of transparent plastic. Organic glass may provide advantages such as toughness, reduced weight, improved thermal insulation, ease of colour modification (incorporation of colorants in the plastic when molding) or the like. Examples of organic glasses or plastics include polycarbonate, acrylonitrile butadiene styrene, polyesters (polyethylene terephthalate (PET), modified PET), acrylics (polymethyl methacrylate) or modified acrylics (e.g. imidized, rubber toughened, stretched or the like), polyester carbonate, allyl diglycol carbonate, polyether imide, polyether sulfone (polysulfone, PSU), cellulose acetate, cellulose butyrate, cellulose propionate, polymethyl pentene, polyolefins, nylon, polyphenylsulfone, polyarylate, polystyrene, polycarbonate, polysulfone, polyurethane, polyvinyl chloride, styrene acrylonitrile , ethylene vinyl acetates, or the like. Where the one or more glass is a rigid or flexible plastic, one or more of the components of the switching material may be selected to be immiscible, or insoluble, with one or more of the components of the substrate, to prevent diffusion into the substrate. For example, a solvent or plasticizer used in some embodiments described herein may be immiscible, or insoluble, with a plasticizer used in an organic glass. Combinations of substrates and switching material materials with one or more immiscible components may be selected in this way. In some embodiments, a layer of plastic (e.g. PET film) may be included between the substrate and the switching material, to prevent diffusion of plasticizers or other components into the substrate. Substrates may independently be of any suitable thickness. Substrates may independently be coated with, or comprise anti-scratch layers, security films, heat or infrared reflecting or absorbing materials, or UV reflecting or absorbing materials or the like. A substrate may be tinted or may comprise coatings or additives to block some wavelengths of light (e.g. portions of UV, VIS, IR incident light or the like)..
Color and depth of coloration of tinted glass may be selected to achieve certain levels of light transmission (visible, UV or IR), or to harmonize with the site of installation e.g. exterior automotive paint, building envelope, or to harmonize with other components of a laminated glass. Glass color may be described with reference to colour values L*a* and b*, and/or light transmittance (LTA).

[0032] The substrate may be of uniform or varying thickness, and of any suitable dimension.
For example, the substrate may have a thickness from about 0.01 mm to about 10 mm, or any amount or range therebetween, for example 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 mm, or from about 0.012 mm to about 10 mm, or from about 0.5 mm to 10 mm, or from about 1 mm to 5 mm, or from about 0.024 mm to about 0.6 mm, or from about 0.051 mm (2 mil) to about 0.178 mm (7 mil). In some embodiments, the thickness and/or material of a first substrate differs from the thickness and/or material of a second substrate.

[0033] Conductive coatings may include a transparent conducting oxide (TCO) such as indium tin oxide (ITO), fluorine tin oxide (FTO) or the like, metal or metal oxide coatings (e.g.
silver, gold or the like), transparent conducting polymers, or other substantially transparent conductive coatings. Examples of transparent substrates with conductive coatings include ITO-coated glass, or FTO-coated glass (e.g. TEC glass from Pilkington). For embodiments comprising co-planar electrodes, the electrode pattern (e.g. interdigitated electrodes such as that illustrated in Figure 3c) may be etched into a conductive coating on the substrate, or printed on a substrate. In some embodiments, a substrate with a conductive layer may be ITO-coated glass, or ITO-coated PET.

[0034] In some embodiments, both first and second electrodes may be disposed on one substrate. First and second coplanar electrodes may be etched into the conductive coating or printed on the surface of the substrate in a suitable pattern e.g., a discontinuous conductive coating providing first and second electrodes on the same substrate. In such embodiments, a second substrate may lack a conductive coating, and first and second busbars and electrical connectors may be disposed on the first and second electrodes of the first substrate. PCT
publication W02012/079159 describes coplanar electrode configurations that may be useful in some embodiments.

[0035] Switching material: examples of switching material and methods for preparing are described in PCT/CA2013/000522, with a priority claim to US 61/652,466 filed May 29, 2012;
and PCT/CA2013/000339, with a priority claim to US 61/706,001 filed September 26, 2012. In some embodiments, the switching material may be disposed upon a first substrate, or 'sandwiched' between a first substrate and a second substrate. The switching material may be a liquid, a gel, a solid or a semi-solid, and may be formed in a layer of suitable thickness. Suitable thickness of a switchable film may be dependent on one or more of a desired light transmission in a dark state, a faded state or both a dark state and a faded state; a desired optical clarity (haze), or a desired thickness of a finished switchable film or switchable article.
Examples of thickness ranges include from about 0.1 micron (micrometer, gm) to about 100 microns, or any amount or range therebetween, for example from about 10 microns to about microns, or from about 0.1 micron to about 10 microns, or from about 0.5 micron to about 5 microns, or from about 0.5 micron to about 2.5 micron or any amount or range therebetween. In some embodiments, the layer of switching material is of uniform, or substantially uniform, thickness. In some embodiments, the layer of switching material is of non-uniform thickness.

[0036] A switchable film, or switchable article comprising a switchable film, may have a switching time (to transition from a dark state to a light state, or from a light state to a dark state) of from about 10 seconds to about 5 minutes, or any amount or range therebetween. Switching time may be altered by varying one or more of thickness of switching material or composition of the switching material.

[0037] A switching material may comprise a compound having both electrochromic and photochromic properties. With such compounds present, the switching material may darken (e.g.
reach a 'dark state') when exposed to of light in the UV and/or VIS range (e.g. from about 350 to about 450 nm), and may lighten ("fade", achieve a 'light state") when exposed to a voltage, or when exposed to light that excludes wavelengths below about 475 nm. Such a switching material may be alternately described as an auto-darkening material. In some embodiments, the switching material may fade upon exposure to selected wavelengths of visible (VIS) light, without sacrifice of the ability to be electrofaded when restored to a darkened state. In some embodiments, the switching material may darken when exposed to light comprising wavelengths from about 350 nm to about 450 nm, or any amount or range therebetween, and may lighten when a voltage is applied. The switching material may be substantially optically clear, or demonstrate no more than 1%, no more than 2% or no more than 3% haze in both faded and dark states.

[0038] A switching material may comprise (by weight percent) about 3 to about 20 parts polymer or polymer matrix, about 60 to about 85 parts solvent, about 0.1 to about 10 parts ionic material (e.g. salt or the like), about 0.1 to about 30 parts of a compound having electrochromic and photochromic properties. The polymer matrix may be formed from crosslinking of a crosslinkable polymer. Generally (without wishing to be bound by theory), a switching material comprising a greater proportion of chromophore, solvent and/or ionic material may have a faster switching time than a switching material with a lesser proportion of chromophore, solvent and/or ionic material. A thinner switchable material may have a faster switching time than a thicker one.
A switching material with a higher degree of cross-linking may have a slower switching time than one with a lesser degree of cross-linking. A switching material with a greater proportion of crosslinkable polymer, rheology modifier, or crosslinkable polymer and rheology modifier may have a slower switching time than one with a lesser proportion of thermoset polymer, rheology modifier, or thermoset polymer and rheology modifier. A switching material may be applied to a substrate using roll-to-roll coating, as is known in the art, and a second substrate attached thereto, to provide a variable transmittance filter.

[0039] Solvents, ionic components, polymers, rheology modifiers, crosslinking agents, crosslinking systems and/or other components of switchable films are addressed in the indicated patents and applications. A switching material may further comprise one or more other additives, such as dyes, UV light stabilizers, antioxidants, salts, surfactants, adhesion promoters, charge carriers, charge compensators or the like.

[0040] Compounds: Examples of compounds having electrochromic and photochromic properties ("chromophores") include some diarylethenes. Examples of such diarylethenes are described in PCT/CA2012/000910 filed September 21, 2012, US 7,777,055 and W02010/142019, and include1,2-diaryl cyclopentene compounds. The chromophore comprises two isomers, a ring-open, or open, isomer and a ring-closed, or closed, isomer. These chromophores are reversibly convertible between open and closed forms with the application of voltage or light.

[0041] Oxidation of the chromophore to convert a ring-closed form to a ring-open form may be induced by application of a voltage to a switching material comprising the chromophore, and may be independent of the polarity of the applied voltage. The chromophore may be an anodic species, that is, the electrochromic colour change occurs primarily at the anode of an electrochromic film or device. The amount of chromophore that may be incorporated in the switching material can be an amount sufficient to provide the desired light transmission in dark state, faded state or both dark and faded states, and in any case less than or equal to a solubility limit of the chromophore in the switching material. The switching material, when prepared, may be substantially free of undissolved components, including undissolved chromophore, undissolved polymers, undissolved ionic materials or the like. A suitable amount of chromophore may provide a switchable film, article comprising a switchable film or a switchable article with a desired level of light transmission or absorption in a dark state, a faded state or a dark state and a faded state. In some embodiments, a suitable amount of chromophore may be selected to complement the level of light transmission when combined with a static filter, such that the light absorption of the switching material in the dark state, faded state or dark state and faded state combined with the light transmission of the static filter provides the desired light transmission. A
static filter may be a non-switching layer or component of the film or article.

[0042] For example, one or more chromophores may be present in a switching material in an amount (% weight) of about 0.05% to about 30%, or any amount or range therebetween, for example about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28 or 29%. Examples of such chromophores include, but are not limited to, the following:

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F F
F Ill F
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o . . oF F F
F
? F e F
(0 S /\ /\ S
c? c \ / ...oz Ss \ /
\ /
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r , /0 0\i .
\ . 0 , 0 1 F F
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[0043] Generally, a switching material may be coated at a suitable thickness onto a conductive coating of a substrate. A second layer may be applied on the switching material ¨ the second layer may be a transparent conductive layer, or a substrate comprising a transparent conductive material (e.g. ITO coated PET). The step of laminating may be preceded by, or followed by, a step of crosslinking or curing of the switching material. The step of curing may comprise heating the composition to a temperature suitable for crosslinking (e.g. about 50 to about 90 C, or any amount or range therebetween. The step of disposing may be preceded by a step of filtration of the composition.

100441 Examples of substrates include polymer films such as PET, and may further comprise a conductive coating, such as ITO; the substrate may be a moving web. The first and/or second substrates may be independently opaque or transparent, or substantially transparent. The substrate may be optically clear. In some embodiments, when the switching material is disposed upon, or sandwiched between the substrate(s), the switching material is optically clear (e.g.
demonstrating a haze of less than about 5%, less than about 4%, less than about 3%, less than about 2% or less than about 1%). Haze may be measured using methods known in the art, for example use of an XL-211 Hazemeter from BYK-Gardner, according to manufacturer's instructions.
[0045] The switching material may have a high viscosity at room temperature and may be made into a lower-viscosity liquid by heating to allow it to be applied or coated onto the substrate. In one embodiment, the switching material is heated to about 100 C and pressed between the substrates. Alternately, the switching material may be cast as a liquid and then further treated to increase the viscosity of the material to form a gel ¨ the switching material may be dried (evaporation of a co-solvent), or a switching material comprising a crosslinkable resin may be cured to increase the viscosity to form a gel. Curing the switching material may be accomplished with chemical crosslinking, temperature or UV light; other methods may be suitable with different formulations. One skilled in the art will appreciate that this polymerization and/or cross-linking can be initiated by chemical-, thermal-, or photo-type initiators. The switching material may then adhere to conductive layers on first and second substrates to form an integral structure. In some embodiments, components of the switching material or composition may be combined in particular order, or in particular subcombinations ('parts'), with the parts combined at a later point. Preparation of first, second and/or third parts may be advantageous to solubilize one or more components of a composition, prevent side reactions, or to prevent initiation of crosslinking ('curing') before the formulation is complete or ready for casting or coating. For example, a switching material for coating on a substrate may be prepared according to the steps of: providing a first part comprising a crosslinkable polymer, a chromophore, an ionic material and a first portion of a solvent; providing a second part comprising an optional hardener, a crosslinking agent and a second portion of the solvent; providing an accelerant and an optional co-solvent (e.g. MEK, THF or the like, which may be removed before laminating the second substrate); combining the first part and the second part; and combining the third part with the combined first and second parts. Disposition of the switching material may be performed in an environment of reduced oxygen (e.g. less than 100 ppm) and/or reduced humidity (e.g. less than 100 ppm relative humidity) [0046] A suitable thickness may be selected such that the composition is of the desired thickness once the co-solvent is evaporated (if the switching material comprises a co-solvent), or the final layer is of the desired thickness following cooling and/or crosslinking of the coated switching material. For example, to obtain a final thickness of about 50 microns, a switching material with co-solvent may be applied to the substrate in a layer of about 100 to about 120 microns.
[00471 Once the filter has been made, it may further be cut to size, and/or sealed around the perimeter. Electrical connections may be made to the electrodes (transparent conductive layers).
The electrical connection can be made by applying bus bars onto the substrates in contact with the transparent conductive coating. In some embodiments, busbars may be applied on the substrate before disposition of the switching material, or before lamination of the substrate to the switching material. Electrical leads (electrical connectors, connectors) can then be attached to the bus bars.
100481 Switching materials and optical filters as referenced herein may be particularly suitable for use with thermoforming, injection molding or other plastic-shaping methods involving the application of heat, as the components of the switching material, in particular the chromophores, are tolerant of elevated temperatures ¨ from about 80 C to about 140 C or any amount or range therebetween for a suitable period of time. To allow conformation of the switchable film to the mold or form, and forming or injecting the transparent plastic layer. Examples of suitable times may range from a few seconds or minutes, to an hour or more.
100491 Heat-attenuating layer [0050] A switchable article may include a heat attenuating layer between the switching material and the injection molded or thermoformed plastic. Inclusion of a heat-attenuating layer between the switchable film and the transparent plastic layer provides insulation from the melted or heated plastic, and further protection of the switching material may be provided by rapidly cooling the transparent plastic once molded or shaped. The heat attenuating layer may be transparent, or substantially transparent. The heat attenuating layer may have a low thermal conductivity. The heat attenuating layer may have a heat transfer coefficient less than that of the molten plastic injected into the mold cavity. The heat attenuating layer may be infrared radiation reflective. "Heat" includes infrared radiation from a heat source; a heat source may include incident light on the article, or may include heat from the transparent plastic layer in a forming, molding or casting process involved in producing a switchable article, or in laminating a switchable article. The heat attenuating layer, when positioned between the switchable film and the transparent plastic layer during production of the article may, in part, mitigate the heat to which the switchable film is exposed during production of a switchable article.
[0051] The heat attenuating layer may be applied directly to one side of the switchable film by laminating, spraying, coating, dipping, sputter coating, magnetron sputtering, electron beam evaporation, ion beam sputtering, plasma enhanced chemical vapor deposition, or the like. In some embodiments, the heat attenuating layer may be applied to a substantially transparent plastic film (e.g. PET), and the film in turn laminated to the switchable film with a substantially transparent adhesive. In some embodiments the heat attenuating layer comprises indium tin oxide (ITO), and is an infrared blocking layer. The ITO layer may be of any suitable thickness providing sufficient transparency is maintained, e.g. from about 1000 to about 3000 angstroms thick. In some embodiments, one of the transparent conductive layers may be a heat attenuating layer.
[0052] A heat attenuating layer may be a heat-activated adhesive. In some embodiments, a layer of heat-activated adhesive may be applied to an outer surface of a switchable film before thermoforming the switchable film adjacent to, or between transparent plastic layers.
[0053] Transparent plastic layer [0054] A transparent plastic layer may comprise polycarbonate, acrylonitrile butadiene styrene (ABS), polyesters (PET, PETG), acrylics (polymethyl methacrylate, PMMA) or modified acrylics (imidized, rubber toughened, stretched or the like), polyester carbonate, allyl diglycol carbonate, polyether imide, polyether sulfone (polysulfone, PSU), cellulose acetate, cellulose butyrate, cellulose propionate, polymethyl pentene, polyolefins, nylon, polyphenylsulfone, polyarylate, polystyrene, polycarbonate, polysulfone, polyurethane, polyvinyl chloride, styrene acrylonitrile (SAN), EVA, or the like. The transparent plastic may comprise additives such as colorants, mold release agents, adhesion promoting agents, antioxidants, UV
absorbing agents or the like. In some embodiments, it may be advantageous to include a layer of plastic (e.g. PET
film) between the switchable film and the transparent plastic layer to prevent diffusion of plasticizers or other components of the switchable film into the transparent plastic. This plastic film may be, or be a vehicle for, a heat attenuating layer.
[0055] In some embodiments, a decorative ink may be applied to the surface of the heat attenuating layer, or to a surface of the switchable film, before the transparent plastic layer is applied, thereby encapsulating the ink layer in the interior of the switchable article. Figure 1 shows an example of such an ink application. Other patterns may include labels or manufacturer information, or the like. The ink may be of any suitable type, comprising polycarbonate resins, polyester resins or combinations thereof. The ink may be applied by screen printing, mask or spray jet, pad printing or the like.
100561 Making a switchable article [0057] The transparent plastic layer may be formed by any suitable technique, including molding, which includes injection molding, blow molding, injection molding, compression molding, injection-compression molding, thermoforming, vacuum forming, film insert molding or the like, or a combination thereof. In some embodiments, techniques may be combined, such as forming the switchable film with heat attenuating layer into the desired shape (e.g. the inside of a mold), and molding the transparent plastic layer onto the switchable film with heat attenuating layer.
[0058] In accordance with another aspect, there is provided a method of preparing a switchable article comprising: providing a switchable film; disposing a heat attenuating layer on a side of the switchable film; and molding a transparent plastic layer in contact with the heat attenuating layer.

[0059] In accordance with another aspect, there is provided a method of preparing a switchable glazing comprising: providing a switchable film; disposing a heat attenuating layer on a side of the switchable film; and laminating a transparent plastic layer in contact with the heat attenuating layer.
[0060] In accordance with another aspect, there is provided a method of preparing a switchable article comprising: providing a switchable film; disposing a heat attenuating layer on a side of the switchable film; inserting the switchable film with heat attenuating layer into a mold;
trimming the switchable film with heat attenuating layer to fit the mold; and injecting a molten transparent plastic resin into the mold cavity, the transparent plastic resin contacting the heat attenuating layer and adhering thereto; cooling the transparent plastic resin and removing the molded switchable article from the mold. Adhesion of the transparent plastic resin to the heat attenuating layer may be by melt-fusion, or may be by activation of a heat-activated adhesive applied to a surface of the switchable film, the heat attenuating layer, or a combination thereof [0061] Referring to Figure 3, steps for a method of preparing a switchable glazing are set out generally at 50. A first step 52 provides a switchable film. A heat attenuating layer is disposed on a side of the switchable film (54), and a transparent plastic layer is molded in contact with the heat attenuating layer (56). The transparent plastic layer may be applied by any of several methods including dip or spray molding, vacuum forming or injection molding or injection-compression molding. Where the transparent plastic layer is injection molded, the step of molding may be preceded by a step of placing the switchable film in an injection mold, with the heat attenuation layer facing the cavity of the injection mold. Step 54 may be preceded by a step of preheating one or both portions of the mold. In some embodiments, a step of molding may be preceded by a step of trimming the switchable film to fit the mold, and/or a step of applying decorative ink to the switchable film.
[0062] Figure 4 shows generally at 40 a switchable film 14 with a heat attenuating layer 12 applied to one side, positioned against a portion 42 of a mold for injection molding of a plastic article, according to one embodiment. The switchable film 14 may be held in position on the mold portion 42 by any suitable method ¨ for example, by vacuum or static, or by gravity, if the mold is positioned suitably, or a combination thereof. The profiles of portions 42 and 44 of the mold define a cavity 46 into which the transparent plastic injected via injection ports in platen 47 and mold 42, and compressed with pressure applied to the mold portions by platens 47, 48 to form the transparent plastic layer 16 of the switchable article, melt-fused to the switchable film and heat attenuating layer. The mold is opened, and the switchable article removed. A mold or form may be made of any suitable material for withstanding the conditions for forming or molding. In some embodiments, the mold portions may be heated or cooled independently to suitable temperatures, as desired. For example, both portion 42 and 44 may be heated to a temperature that the switchable film will tolerate (without damage or loss of function) - this temperature may be below that of the melted plastic for injection into the cavity. Where the temperature of the melted plastic is greater than a temperature that the switchable film will tolerate, the heat attenuating layer may provide sufficient thermal insulation to reduce the heat transferred from the melted plastic to the switchable film.
[0063] In some embodiments, the switchable film may have electrical leads attached before incorporation into the switchable article by film in mold injection molding.
The switchable film may be positioned against the mold portion and anchored as described, with the electrical leads folded behind the switchable film, between the film and the mold portion. The mold may be closed and the plastic injected. In other embodiments, a switchable film with busbars is incorporated into a switchable article, and electrical connectors added after the molded, switchable article is removed from the mold. Some mechanical systems for connecting an electrical connector to a busbar are described in PCT publication W02008/134669. For example, a compressive edge clip may be provided to secure an electrical connector to a bus bar;
the compressive edge clip may have protrusions (tabs, or teeth) that penetrate the substrate of the switchable film to contact the busbar.
[0064] Polycarbonate is available from several suppliers (e.g. SABIC, Bayer, Styron, Teijin or others), with a variety of properties. Selection of the polycarbonate, or other transparent plastic, will be dependent on the intended use of the switchable article. For example, polycarbonate for use in an automotive glazing (window or sunroof) will need to meet safety testing and other performance objectives - an example of a polycarbonate material suitable for a vehicle glazing is MakrolonTM (Bayer).

[0065] Preheating one or both portions of the mold may provide additional flexibility to the switchable film and/or heat attenuating layer, allowing the film to conform to the surface of the mold more easily. Resin may be injected under pressure as a single shot through one or several injection ports. Further compression of the layers may be provided by application of pressure by the platens 47, 48 to which the molds 42, 44 are attached Cooling of the melted plastic once injected into the mold may be controlled by water or air cooling of the mold portions. The rate of cooling may be controlled so as to minimize or prevent the development of molding artefacts, shrinkage or temperature related defects in the transparent plastic layer, and to minimize the time the article components are exposed to the temperature of the melted plastic. .
[0066] To thermoform a switchable film, the film is laid over a form, and heat applied to the film; a vacuum may also be applied to draw the switchable film over the form to attain the desired shape, and the form may be preheated, or not. Alternately, the film may be placed between positive and negative forms (e.g. two halves of a mold), and heat and pressure (sufficient to shape the film) applied by the first and second negative forms to the film therebetween, to attain the desired shape. The film is allowed to cool below the plastic point of the substrates, and removed from the form(s). A transparent plastic layer of the corresponding shape is also prepared by injection molding, thermoforming, vacuum forming or other suitable method. To prepare the switchable article, the formed switchable film and formed plastic layer are mated, and affixed with an adhesive layer between them. The adhesive layer may be a pressure sensitive or a heat sensitive adhesive, and the film and plastic layer may be affixed with further heat and/or pressure to form the article.
[0067] The switchable article may be of any suitable thickness. For example, an architectural or vehicle glazing may be from about 3mm to about 6mm in thickness overall, [0068] Coating system [0069] After forming the switchable article, one or more abrasion resistant layers, weathering protection layers or the like may be applied to surface A, surface B or both, of the switchable article. A weathering layer may include a polyurethane or acrylate coating, or a top-coat with a primer. A primer may comprise a UV absorbing component in a compatible polymer and solvent system for application to a surface of the switchable article. A
topcoat may be applied over the primer, providing abrasion resistance and additional UV resistance.
Examples of weathering layers and coating systems, and methods of applying the layers and components are described in, for example, US Patent Publication Nos. US 2007/0026235, US
2007/0104956.
Weathering layers and coating systems may be applied to the switchable article by any technique known in the art, for example spray coating, curtain coating, dip coating, spin coating, flow coating, sputter coating, magnetron sputtering, electron beam evaporation, ion beam sputtering, plasma enhanced chemical vapor deposition, or the like.
[0070] Anti-scratch: an abrasion-resistant coating may be applied to the switchable article to prevent distortion or surface damage, and preserve optical clarity; anti-scratch coatings may be particularly beneficial for use with transparent plastics. An example of an abrasion-resistant coating may be a polysiloxane coating (e.g. Momentive AS5400, AS4700 polysiloxane wet-coat system) [0071] Security coating: A security coating may be applied to the switchable article to prevent release of particles during breakage. Examples of such materials include PVB/PET composites or hard-coated PET films (e.g. SPALLSHIELDTM (DuPont).
[0072] UV-blocking: One or more layers may comprise a UV blocking component.
Adhesive layers such as PVB may have additives that block UV (e.g. US 6627318); some transparent plastics, or some substrates may be made of a material that has been treated with a UV blocking material (e.g. UV-blocking PET), or have a UV blocking layer applied thereto.
It may be cost effective to incorporate into the variable transmittance optical filter a substrate that blocks UV ¨
this may be advantageous in protecting the switching material from some incident UV light.
Surprisingly, the switchable films will still switch even when a UV blocking substrate that blocks a substantial portion of incident UV light of 380 nm or greater, and all UV light below about 375 nm.
[0073] Sound insulation: Multiple layers of materials with different properties may diffuse sound or vibration, reducing the amount of sound or vibration transmitted through the article.
Sound insulation may be provided by the layers of the switchable article as described herein, and/or by inclusion of an additional acoustic layer. Acoustic PVB may be known by trade names such as SAFLEXTM or VANCEVATM. US 5190826 describes composition comprising two or more layers of resins of differing polyvinyl acetals; the acoustic layer may be in the range of 0.2 to 1.6 mm. US 6821629 describes an acoustic layer comprising an acrylic polymer layer and polyester film layer. Acoustic layers comprising PVC, modified PVC, polyurethane or the like may also be used.
[0074] Self-cleaning coating: a self-cleaning coating may be applied to an outboard surface of the switchable article. Several examples of such coatings, and methods of applying them are known ¨ examples include hydrophilic coatings based on TiO2 (e.g. Pilkington ACTIVTm) and hydrophobic coatings (e.g. AQUACLEANTM or BIOCLEANTm).
[0075] IR Reflecting: Examples of such films include US 2004/0032658 and US
4368945.
Alternately IR blocking materials may be incorporated into a layer of plastic, or an adhesive layer and applied to the switchable film. An IR blocking layer may reflect or absorb IR light.
Reflection of IR may reduce the solar heat gain of the interior space, whereas absorption of IR
may increase the temperature of the switchable article, which may be advantageous in increasing the switching speed of the switchable article.
[0076] Coatings or treatments applied to the inboard or outboard surfaces of transparent switchable articles are generally optically clear. Other examples of coatings or treatments may include antiglare or anti-reflective coatings.
[0077] Borders: It may be desirable for some switchable articles such as vehicle or automotive glazings to have a border (opaque, partially opaque or faded, for example) to provide esthetic enhancement, or mask wires ,busbars, connectors or other components of, or used with, a switchable article, or mask one or more antennas embedded in the glazing.
[0078] Identification marks: Identification marks may be necessary for some switchable articles ¨ it may be a manufacturing requirement for automotive or architectural glazings or other articles, for example, to be labeled with information pertaining to manufacturer, testing standards or other regulatory or required information. It may also be desired to 'personalize' a switchable article with a name, logo, diagram or other esthetic element. Inks or pigments used for borders or identification markings need to adhere to the surface to which they are applied (e.g. a part of the switchable film insert), and be suitably durable to withstand testing and handling of the article during manufacture and installation, and during normal use. US Publication No.

provides some examples of polyester-polycarbonate inks that may be suitable.
100791 Controlling a switchable article [0080] The switching material may be transitionable from a light state to a dark state on exposure to light, and further may be transitionable from a dark state to a light state upon application of a voltage. The light may have a wavelength from about 350 nm to about 450 nm.
For application of the voltage, the switchable article may further comprise an electrical connector configured for electrically connecting each of the transparent conductive layers to a voltage source.
[0081] Referring to Figure 5, Electrical leads may connect the switchable article to a control circuit comprising a power source (voltage source) 146. A switch 148 may open and close the control circuit to control power to a switchable film of the switchable article 10 based on input.
Switch 148 may be a two-way or three-way switch, or may be a multi-state control device such as a potentiostat, and allow selection of different states of the variable transmittance layer. Input may come from a user (e.g. operation of a switch), or some other input such as a timer, pre-existing instructions (e.g. programmed into a memory comprising part of the control circuit) a device monitoring the light transmittance of the switchable optical filter, incident light, and may be operable by a user, a preexisting program, timer or another component of the control circuit.
[0082] Other components of a control circuit may include a DC-DC converter for converting the voltage from the power source to an appropriate voltage, a voltage regulator, timer, light sensor, voltage or resistance sensors or the like. Control circuits and systems that may be used with variable transmittance optical filters and layered compositions according to various embodiment are described in, for example, PCT publication W02010/142019, and PCT/CA2013/000381, with a priority claim to U.S. Provisional patent application 61/625,855 filed April 18, 2012.

[0083] Electrical leads 142, 144 may extend out one side of the laminated glass (such as in Figure 6), and layer. Molding of the switchable article may encapsulate busbars 158 a, b and a portion of the electrical leads 142, 144 contacting busbars 158 a, b, forming a sealed unit.
[0084] Figure 6 and 7 shows a schematic diagram of a switchable film, illustrating busbars and electrical leads connected thereto. A switchable film comprising a layer of switching material 152 between first 154 and second 156 substrates is electrically connected to electrical leads 142, 144 via busbars 158a, b applied to a conductive coating 160a, 160b on substrates 154, 156, in contact with the switching material 152. The substrates of the switchable optical filter have opposing overhanging edges, cut to expose the conductive coating. Optional peripheral seal 164 seals the cut edge of the switching material.
[0085] Busbars, electrical connectors and control circuits: Busbars may be applied to a portion of the conductive layer on opposing sides of the switching material, so that a voltage differential is created across the switching material to effect the switch.
The busbars may be of any suitable material to provide a low-profile conductive area suitable for attachment of an electrical connector thereto. Examples of suitable materials include conductive adhesive, conductive ink, conductive epoxy, metal mesh or film or the like, comprising at least one type of metal such as aluminum, gold, silver, copper or the like. The conductive material may be applied to the conductive surface by any of several methods known in the art, including printing, painting, screenprinting ('silkscreening') or the like. Electrical connectors or leads may be of any suitable material and may be affixed to the busbar by any suitable methods, including adhesion (conductive adhesive or conductive epoxy), clips, rivets, conductive tape, wire or the like. A
suitable electrical connector may be suitably durable or heat-resistant to withstand temperatures associated with thermoforming or injection molding of polycarbonate or other plastics.
[0086] A control circuit can be used to switch the electrical voltage on or off, based on input from an automated or semi-automated device (e.g. an irradiance meter, thermometer), a building or vehicle environmental control system, a user or some other input, and can also be used to modulate the voltage to a predetermined level. A power source for may include an AC line voltage in a house or other building, a DC power source (e.g. a battery of a vehicle, or in a separate battery or power pack), an energy harvesting power source (e.g. solar panel) or the like.

The control circuit may comprise one or more switches (transistor, relay, or electromechanical switch) for opening and closing a circuit between the voltage regulators and the optical filters, an AC-DC and/or a DC-DC converter for converting the voltage from the power source to an appropriate voltage; the control circuit may comprise a DC-DC regulator for regulation of the voltage. The control circuit can also comprise a timer and/or other circuitry elements for applying electric voltage to the variable transmittance optical filter for a fixed period of time following the receipt of input.
[0087] Embodiments include switches that can be activated manually or automatically in response to predetermined conditions. For example, control electronics may process information such as time of day, ambient light levels detected using a light sensor, user input, stored user preferences, occupancy levels detected using a motion sensor, or the like, or a combination thereof, the control electronics configured to activate switches for applying voltage to the optical filter in response to processed information in accordance with predetermined rules or conditions.
Where the multilayer composition according to various embodiments is part of an automotive article (window or sunroof, or the like), the article may be installed in the vehicle and electrically connected to the vehicle's electrical system, through wiring in the frame, dash or roof, or connected to rails or guide tracks as may be used for some automotive roof applications.
[0088] In one embodiment, the control electronics comprises a user-activated switch that passes the DC voltage from the power source substantially directly to the variable transmittance optical filter. The user activated switch can be a normally-open push button, or another type of switch. A
switch may be configured to remain closed for a predetermined amount of time following actuation, thereby facilitating application of voltage to the optical filter for sufficient time to effect a state transition.
[0089] The voltage to be applied for transitioning the optical filter may be from about 0.1 V to about 20 V, or any amount or range therebetween. In some embodiments, the amount of voltage applied is from about 0.1V to about 5V, or from about 1V to about 10 V, or from about 1.0 V to about 2.2 V, or from about 0.5V to about 3V, or from about 1.2V to about 2.5 V, or from about 1.8 V to about 2.1 V, or any amount or range therebetween. In some embodiments, the voltage applied is less than about 12 V, or less than about 6 V, or less than about 3 V or less than about 2.5 V, or about 2 V.
[0090] The term "mil" as used herein, refers to the unit of length for 1/1000 of an inch (.001).
One (1) mil is about 25 microns; such dimensions may be used to describe the thickness of an optical filter or components of an optical filter, according to some embodiments of the invention.
One of skill in the art is able to interconvert a dimension in `mil' to microns, and vice versa.
[0091] "About" as used herein when referring to a measurable value such as an amount, a temporal duration, and the like, is meant to encompass variations of 20% or 10%, more preferably 5%, even more preferably 1%, and still more preferably 0.1% from the specified value, as such variations are appropriate to perform the disclosed methods.
[0092] Other Embodiments [0093] It is contemplated that any embodiment discussed in this specification can be implemented or combined with respect to any other embodiment, method, composition or aspect, and vice versa. Figures are not drawn to scale unless otherwise indicated.
[0094] The present invention has been described with regard to one or more embodiments.
However, it will be apparent to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as defined in the claims. Therefore, although various embodiments of the invention are disclosed herein, many adaptations and modifications may be made within the scope of the invention in accordance with the common general knowledge of those skilled in this art. Such modifications include the substitution of known equivalents for any aspect of the invention in order to achieve the same result in substantially the same way. Numeric ranges are inclusive of the numbers defining the range. In the specification, the word "comprising" is used as an open-ended term, substantially equivalent to the phrase "including, but not limited to," and the word "comprises" has a corresponding meaning. As used herein, the singular forms "a", "an" and "the"
include plural referents unless the context clearly dictates otherwise. Citation of references herein shall not be construed as an admission that such references are prior art to the present invention, nor as any admission as to the contents or date of the references. All publications are incorporated herein by reference as if each individual publication was specifically and individually indicated to be incorporated by reference herein and as though fully set forth herein. The invention includes all embodiments and variations substantially as hereinbefore described and with reference to the examples and drawings.

Claims (28)

1. An injection-molded, switchable article, comprising:
a. a transparent plastic layer; and b. a switchable film.

2. A thermoformed, switchable article, comprising:
a. a transparent plastic layer;
b. a switchable film; and c. an adhesive layer

3. The switchable article of claim 1, further comprising an adhesive layer.

4. The switchable article of any one of the preceding claims, further comprising a heat-attenuating layer.

5. The switchable article of any one of the preceding claims, wherein the switchable film comprises a first and a second substrate, a first and a second electrode disposed on the surface of at least one of the substrates; and a switching material disposed between a first and a second substantially transparent substrates and in contact with the first and second electrodes.

6. The switchable article of any one of the preceding claims, the switching material comprising one or more compounds having electrochromic and photochromic properties.

7. The switchable article of any one of the preceding claims, comprising an electrical connector configured for electrically connecting each of the transparent conductive layers to a voltage source.

8. The switchable article of any one of the preceding claims, wherein the heat attenuating layer may be disposed between the transparent plastic layer and the switchable film.

9. The switchable article of any one of the preceding claims, wherein the heat attenuating layer may be an infrared blocking layer.

10. The switchable article of any one of the preceding claims, wherein the switching material may be transitionable from a light state to a dark state on exposure to light, and transitionable from a dark state to a light state upon application of a voltage.

11. The switchable article of any one of the preceding claims, wherein a portion of the light may have a wavelength from about 350 nm to about 450 nm.

12. The switchable article of any one of the preceding claims, wherein the voltage may be from about 1 to about 5 volts.

13. The switchable article of any one of the preceding claims, wherein the one or more compounds may be diarylethenes.

14. A method of preparing a switchable article comprising:
a. providing a switchable film;
b.
optionally, disposing a heat attenuating layer on a side of the switchable film; and c. molding a transparent plastic layer in contact with the heat attenuating layer.

15. The method of any one of the preceding claims, wherein the step of molding may be preceded by a step of placing the switchable film in an injection mold, with the heat attenuation layer facing the interior of the injection mold.

16. The method of any one of the preceding claims, wherein the switchable film comprises a switching material disposed between a first and a second substantially transparent substrates, each substrate having disposed thereon a transparent conductive layer, the transparent conductive layers each in contact with the switching material.

17. The method of any one of the preceding claims, wherein the switching material comprising one or more compounds having electrochromic and photochromic properties.

18. The method of any one of the preceding claims, wherein the switchable film comprises an electrical connector configured for electrically connecting each of the transparent conductive layers to a voltage source.

19. The method of any one of the preceding claims, wherein the heat attenuating layer is disposed between the transparent plastic layer and the switchable film.

20. The method of any one of the preceding claims, wherein the heat attenuating layer is an infrared blocking layer.

21. The method of any one of the preceding claims, wherein the switching material may be transitionable from a light state to a dark state on exposure to light, and transitionable from a dark state to a light state upon application of a voltage.

22. The method of any one of the preceding claims, wherein a portion of the light has a wavelength from about 350 nm to about 450 nm.

23. The method of any one of the preceding claims, wherein the voltage may be from about 1 to about 5 volts.

24. The method of any one of the preceding claims, wherein the one or more compounds may be diarylethenes.

25. A switchable article produced by the method of any one of the preceding claims.

26. The switchable article of any one of the preceding claims wherein, the switchable article is an architectural glazing.

27. The switchable article of any one of the preceding claims wherein the switchable article is a vehicle glazing.

28. A switchable article as described herein.