JP2013505851A - Fluoropolymer / fine particle filled protective sheet - Google Patents

Abstract

  The present invention describes a particulate-filled film useful as a backsheet for a photovoltaic structure.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application was entitled US Provisional Patent Application No. 60 / 104,914, filed October 13, 2008, entitled “Fluoropolymer / Particulate Filled Protective Sheet”, “Fluoropolymer Films”. US Provisional Patent Application No. 61 / 232,694, filed Aug. 10, 2009, U.S. Patent Application Publication No. 2009 filed Oct. 12, 2009 entitled "Fluoropolymer / Particulate Filled Protective Sheet". No. 060354, and "Fluoropolymer / Particulate Filled Protective Sheet" And claims priority to U.S. Patent Application Serial No. 12 / 576,724, filed October 09, 2009, which is, the contents of these patent applications are incorporated in their entirety herein.

  The present invention relates generally to films and multilayer films having at least one microparticle embedded in the film, and methods for their production useful as packaging materials.

  A multilayer film or laminate is a structure that takes in the properties of a distinct layer and separately seeks to provide improved performance compared to the material. Desirable properties for multilayer films include moisture vapor barrier, weather resistance, cutting resistance, electrical resistance, surface reflectance, opacity, two-sided colors, or other different electromagnetic spectrum effects. Can be mentioned.

  Such laminates up to the present invention often result in property imbalances, are expensive, and are difficult to handle or process. The addition of a material that improves one property can result in the loss of another property at the same time.

  In the field of growing electronic component protection packaging films, it is extremely important to provide a well-tuned and practical balance of desirable properties. For example, a protective backsheet film for a photovoltaic device must provide a combination of properties such as protection from moisture, good dielectric strength, high opacity and / or reflectivity. Achieving these properties in multilayer films has been difficult and expensive.

  In particular, achieving property control by conventional methods of adding suitable fillers often resulted in an improvement in one property with a decrease in another property. For example, the addition of a level of shading filler that is required to obtain a high level of opacity can result in an undesirable increase in moisture permeability. Similarly, the addition of a high level of light shielding filler can result in an undesirable reduction in dielectric strength. In another example, the addition of fillers that increase the reflectivity of the film can result in a multilayer film surface that has poor adhesion when bonded into a photovoltaic device. Previous films have generally provided one or two desirable properties of protective films for electronic devices, but have not been able to provide a superior level of combined protection.

  Further, when fillers are added to the melt extruded multilayer film, the fillers can be difficult to disperse, requiring considerable mixing and can result in increased process time and expense.

  Thus, there is a need for multilayer films that can be tailored to impart one or more improved properties to the photovoltaic sheet. There is also a need for protective films for multilayer films (eg, protective jackets for wire or cable applications) tailored for other protective applications, or other optoelectronic devices (eg, OLEDS).

  The present invention surprisingly provides multilayer films and methods for preparing such multilayer films that overcome one or more of the disadvantages known in the art. It has been discovered that it is possible to make and use multilayer films having properties that are suitable, for example, as packaging materials for electronic devices. This film serves to protect components from heat, moisture, chemicals, radiation, physical damage, and general wear. Such packaging material serves to electrically isolate the active components / circuits of the electronic device. In addition, such materials provide protective buffering for electronic devices (eg, photovoltaic devices), anti-soil properties, chemical resistance, UV resistance, reflectivity, improved flame retardancy. Provides sex, beauty and / or opacity.

  In one aspect, the present invention is a casting composition comprising a carrier liquid, a polymer resin matrix material, and a particulate filler material, wherein the polymer matrix material and particulate filler material are in various volume percent proportions. A casting composition is provided that is included in the composition in a relative amount effective to provide a dry composite film comprising a plurality of filler materials.

  Surprisingly, by selecting one or more of the particulate filler size parameters, the specific filler type and / or the volume fraction of the filler material, while providing an aesthetically pleasing appearance and film It has been found that the opacity of the film can be controlled while providing integrity. In general, the incorporation of less particulate filler improves the integrity of the film while maintaining opacity. Lower moisture permeability or improved dielectric strength may also be provided by lower levels of particulate filler. Accordingly, in certain embodiments, it is preferred that less than 15 volume percent filler be present in the final film.

  Interestingly, it has been found that there is a factor balancing when controlling the volume fraction of the filler. The particle size can also result in film integrity, and in some embodiments, the operator can determine from 1 nanometer (nm) to about 100 nm that none of the single linear dimensions of the particles exceeded 10 μm. One or more filler materials will be selected that cannot be (eg, 0.1 μm). In another embodiment, the particulate filler can have a single dimension of 100 nm to 2 μm. In other embodiments, a portion of the particulate filler can have a single linear dimension greater than 10 μm.

  Selection of the microparticles themselves can help improve film integrity and physical properties (eg, opacity, moisture permeability, IR reflectivity, and dielectric constant). Fine particles include silica particles, aluminum flakes, glass beads, glass microspheres, glass fibers, titanium dioxide particles, barium titanate particles, calcium carbonate, zinc oxide, mica, clay (eg kaolin or other clays), mullite, talc , Iron oxide, carbon black, zinc sulfide, barium sulfate, zinc sulfite, various pigments (eg, cobalt blue aluminate, sodium aluminosulfosilicate), flame retardants (eg, magnesium hydroxide, antimony trioxide, organophosphoric acid) Compound or brominated compound), or one or a mixture of other microparticles suitable for the intended use. In some embodiments, the particle size can be from about 100 nanometers (nm) to about 2 microns (μm).

  In another embodiment, the particles can be reflective in the infrared region of the spectrum. This type of particles can be effective in reducing IR absorption and the associated heat buildup in the film, while at the same time allowing the selection of a range of colors in the visible spectrum. Such IR reflective pigments include Arctic Black 10C909, Black 411, Yellow 193, Brown 12 and Brown 8 from Shepherd Color Company (Cincinnati, OH), and Ferro Corporation (Cleveland OH) 80 from Clerand OH). V-778 Black, PC-9415 Yellow, V-9248 Blue, V-13810 Red, and V-12600 Camouflage Green.

  In another aspect, the present invention provides a film from a casting composition.

  In another aspect, the present invention provides methods for preparing the films and multilayer films disclosed herein.

  In yet another aspect, the present invention provides a photovoltaic device comprising a photovoltaic component protected by (eg, in contact with) the film or multilayer film of the present invention.

  It should be understood that the multilayer film of the present invention may comprise from 2 layers to about 12 layers of material. For example, the multilayer film may repeat the layering of the first layer and the second layer, and so on. One outer layer or two outer layers may be included in the multilayer film structure. This outer layer can be, for example, a fluoropolymer or a non-fluoropolymer. Further, various layer combinations (eg, a first layer, a second layer, a third layer different from the first or second layer, and a fourth different from the first, second or third layer) Layers, etc.) are encompassed by the present invention. This layering can again be repeated as needed for the intended application.

A multilayer film is generally more than 3 kV as measured by ASTM method D3755 when the multilayer film has a thickness between about 0.8 mil and about 2.0 mil (eg, about 1.1 mil). High breakdown strength (kV), solar reflectance greater than 70% as measured by ASTM method E424, or moisture permeability of less than 20 g / m ² / day as measured by ASTM method F1249.

  The present invention also provides methods for preparing the multilayer films described throughout this specification.

  While multiple embodiments are disclosed, still other embodiments of the invention will be apparent to those skilled in the art from the following detailed description. As will be apparent, the invention is capable of modifications in various obvious aspects, all without departing from the spirit and scope of the invention. Accordingly, the detailed description is to be regarded as illustrative in nature and not as restrictive.

  In the specification and claims, the terms “including” and “comprising” are non-limiting terms and are taken to mean “including but not limited to” Should. These terms encompass the more restrictive terms “consisting essentially of” and “consisting of”.

  As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” refer to instructions that the context clearly indicates otherwise. It should be noted that it includes a reference to the plural unless otherwise stated. Similarly, the terms “a” (or “an”), “one or more” and “at least one” are used herein to refer to Can be used interchangeably. It should also be noted that the terms “comprising”, “including”, “characterized by” and “having” can be used interchangeably. .

  Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. All documents and patents specifically mentioned in this specification describe and describe the chemicals, instruments, statistical analyzes and techniques that are reported in their entirety, which may be used in connection with the present invention. For all purposes, including disclosure, incorporated by reference. All references cited in this specification are to be taken as indicative of the level of ordinary skill in the art. Nothing in this specification should be construed as an admission that the invention is not entitled to antedate such disclosure by virtue of prior invention.

The present invention includes various embodiments. In the first embodiment, the present invention provides:
Carrier liquid,
A non-fibrillated non-fluoropolymer or fluoropolymer matrix (polymer resin or polymer matrix) material;
A casting composition comprising a particulate filler material, wherein some of the particles of the particulate filler material exhibit a single linear dimension greater than 10 μm, and the polymer matrix material and particulate filler material are greater than 15 volume percent It relates to a casting composition that is included in the composition in a relative amount effective to provide a dry composite film comprising a filler material.

In the second embodiment, the present invention provides:
Carrier liquid,
A non-fibrillated non-fluoropolymer or fluoropolymer matrix material;
A casting composition comprising a particulate filler material, wherein some of the particles of the particulate filler material exhibit a single linear dimension greater than 10 μm, and the polymer matrix material and particulate filler material comprise less than 15 volume percent It relates to a casting composition that is included in the composition in a relative amount effective to provide a dry composite film comprising a filler material.

In the third embodiment, the present invention provides:
Carrier liquid,
A non-fibrillated non-fluoropolymer or fluoropolymer matrix material;
A casting composition comprising a particulate filler material, wherein none of the particulate filler material particles exhibit a single linear dimension greater than 10 μm, and the polymer matrix material and particulate filler material comprise less than 15 volume percent filling. It relates to a casting composition that is included in the composition in a relative amount effective to provide a dry composite film comprising the agent material.

In the fourth embodiment, the present invention provides:
Carrier liquid,
A non-fibrillated non-fluoropolymer or fluoropolymer matrix material;
A casting composition comprising a particulate filler material, wherein some of the particles of the particulate filler material exhibit a single linear dimension greater than 10 μm, and the polymer matrix material and particulate filler material are greater than 15 volume percent It relates to a casting composition that is included in the composition in a relative amount effective to provide a dry composite film comprising a filler material.

In the fifth embodiment, the present invention provides:
Carrier liquid,
A non-fibrillated non-fluoropolymer or fluoropolymer matrix material;
A casting composition comprising a particulate filler material, wherein some of the particles of the particulate filler material exhibit a single linear dimension greater than 10 μm, and the polymer matrix material and particulate filler material comprise less than 15 volume percent It relates to a casting composition that is included in the composition in a relative amount effective to provide a dry composite film comprising a filler material.

In the sixth embodiment, the present invention provides:
Carrier liquid,
A non-fibrillated non-fluoropolymer or fluoropolymer matrix material;
A casting composition comprising a particulate filler material, wherein none of the particles of the particulate filler material exhibit a single linear dimension greater than 10 μm, and the polymer matrix material and particulate filler material are greater than 15 volume percent filled. It relates to a casting composition that is included in the composition in a relative amount effective to provide a dry composite film comprising the agent material.

In the seventh embodiment, the present invention provides:
Carrier liquid,
A non-fibrillated non-fluoropolymer or fluoropolymer matrix material;
A casting composition comprising a particulate filler material, wherein none of the particulate filler material particles exhibit a single linear dimension greater than 10 μm, and the polymer matrix material and particulate filler material comprise less than 15 volume percent filling. It relates to a casting composition that is included in the composition in a relative amount effective to provide a dry composite film comprising the agent material.

  Removal of the carrier and any other optional additives discussed herein results in a film. The film can be part of the multilayer film structure described herein.

In an eighth embodiment, the present invention provides
Carrier liquid,
A non-fibrillated non-fluoropolymer matrix material;
A casting composition comprising a particulate filler material, wherein none of the particles of the particulate filler material exhibit a single linear dimension greater than 10 μm, and the polymer matrix material and the particulate filler material comprise more than 15 volume percent It relates to a casting composition that is included in the composition in a relative amount effective to provide a dry composite film comprising a large amount of filler material.

  It should be understood that a third layer can be disposed over the second layer to form a composite material. The second layer is encapsulated by the first and third layers. The third layer can also be a non-fluoropolymer or a fluoropolymer from a castable solution.

  Accordingly, the present invention also provides a casting composition, a method of preparing a cast multilayer film from the composition, and a multilayer film formed from the composition. The multilayer film comprises a first outer layer comprising a polymer (eg, a fluoropolymer) that can be cast with water or a solvent as described above, and a second intermediate layer disposed on the first layer as described above. A second layer comprising a water or solvent castable polymer as described above (eg, a fluoropolymer or mixture thereof and a particulate filler material) and can be cast with water or solvent as described above. And a third outer layer disposed on the second layer, including a polymer (eg, a fluoropolymer or mixture thereof).

  Typically, the first outer layer is about 0.01 mils to about 0.7 mils, more specifically about 0.02 mils to about 0.4 mils, most specifically about 0.05 mils to It has a thickness of about 0.3 mil.

  The second intermediate layer is generally from about 0.1 mil to about 0.8 mil, more specifically from about 0.2 mil to about 0.4 mil, and most specifically from about 0.3 mil to about It has a thickness of 0.4 mil.

  The third outer layer can be, for example, from about 0.01 mil to about 0.7 mil, more specifically from about 0.02 mil to about 0.4 mil, and most specifically from about 0.05 mil to about 0 mil. .Thickness of 3 mils.

  The next layer (eg, the fourth and fifth layers) is about 0.01 mils to about 0.7 mils, more specifically about 0.02 mils to about 0.4 mils, most specifically It may have a thickness of about 0.05 mil to about 0.3 mil.

  The phrase “multilayer” film is intended to include multiple layers of one or more films in contact with each other. Three layers are particularly desirable, but there are at least two layers. Additional layers can be included in the multilayer film, such that the multilayer film can include 4, 5, 6-12, and the like.

  The phrase “castable polymer” is intended to mean a fluoropolymer or a non-fluoropolymer that can be dispersed, dissolved, suspended, emulsified, or normally distributed in a liquid carrier medium. The liquid carrier medium may be water, an organic solvent, or any other liquid that can disperse, dissolve, suspend, emulsify, or normally distribute the polymer. The liquid carrier medium may be a suitable liquid mixture. Once distributed within the carrier medium, the polymer and medium can then be deposited or cast onto a support material to form a film. The polymer can be mixed with the first carrier liquid. This mixture can be a dispersion of polymer particles in a first carrier liquid, an emulsion of droplets of a polymer or polymer monomer or oligomer precursor in a first carrier liquid, or a solution of a polymer in a first carrier liquid. May be included.

  The castable polymer can also be a monomeric or oligomeric precursor of the polymer distributed within the carrier liquid. Most commonly, the castable composition is an emulsion or dispersion in an aqueous medium.

  The selection of the first carrier liquid is based on the specific polymer and the form in which the material is to be introduced into the casting composition of the present invention. If a solution is desired, the solvent for the particular fluoropolymer is selected as the carrier liquid. Suitable carriers include, for example, DMAC, NMP, cellosolve, or water. If a dispersion is desired, preferred carriers are those in which the polymer is not soluble. An aqueous solution would be a suitable carrier liquid for the dispersion of polymer particles.

  Most commonly, the castable composition is an emulsion or dispersion in an aqueous medium. A surfactant can be used to prepare the dispersion in an amount effective to alter the surface tension of the carrier liquid so that the carrier liquid can wet the filler particles. Suitable surfactant compounds include ionic surfactants, amphoteric, cationic and nonionic surfactants.

  In one exemplary embodiment, a mixture of polymer and carrier liquid and a dispersion of filler particles in a second carrier liquid are combined to form a casting composition.

  The fluoropolymer is generally selected as the outer layer to provide a chemical, electrical, weather, and / or moisture barrier layer.

  The phrase “fluoropolymer” is known in the art and includes, for example, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), polyvinyl fluoride (PVF), tetra Fluoroethylene / hexafluoropropylene / ethylene copolymer (HTE), chlorotrifluoroethylene / vinylidene fluoride copolymer, chlorotrifluoroethylene / hexafluoropropylene, ethylene / chlorotrifluoroethylene copolymer (ECTFE), ethylene / trifluoroethylene copolymer, Ethylene / tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene / propylene copolymer (TFE / P), tetrafluoroethylene / hexafluoro Lopylene copolymer (FEP), tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer (PFA, for example, tetrafluoroethylene-perfluoro (propyl vinyl ether), polyvinylidene difluoride, hexafluoropropylene / tetrafluoroethylene / vinylidene copolymer (ie THV) and mixtures thereof.

  Fluoropolymers include, for example, polyvinylidene difluoride; copolymers of vinylidene difluoride; copolymers of tetrafluoroethylene, hexafluoropropylene, and vinylidene difluoride; copolymers of tetrafluoroethylene and hexafluoropropylene; and other melt processing The fluoropolymer may be melt-processable as in the case of, for example, polytetrafluoroethylene, a copolymer of TFE and a low level of fluorinated vinyl ether), and the cured fluoroelastomer It may not be workability.

  Examples of commercially available THV polymer, trade name "DYNEON THV 2030G FLUOROTHERMOPLASTIC", "DYNEON THV 220 FLUOROTHERMOPLASTIC", "DYNEON THV 340C FLUOROTHERMOPLASTIC", "DYNEON THV 415 FLUOROTHERMOPLASTIC", "DYNEON THV 500A FLUOROTHERMOPLASTIC", "DYNEON THV 610G “FLUOROTHERMOPLASTIC” or “DYNEON THV 810G FLUOROTHERMOPLASTIC” sold by Dyneon, LLC.

  Examples of commercially available HTE polymers include, for example, the trade name “DYNEON FLUOROTHERMOPLASTIC HTE” (for example, “DYNEON FLUOROTHERMOPLASTIC HTE X 1510” or “DYNEON FLUOROTHERMOPLASTIC HTE X 1705” sold by Ly, Dy. It is done.

  Examples of commercially available vinylidene difluoride-containing fluoropolymers include, for example, such fluoropolymers having the trade name “KYNAR” (eg, “KYNAR 740”) sold by Atofina (Philadelphia, Pa.); Ausimont Such a fluoropolymer having the trade name “HYLAR” (eg, “HYLAR 700”) sold by USA (Morristown, NJ); and the trade name “FLUOREL” sold by Dyneon, LLC ( For example, such fluoropolymers having “FLUOREL FC-2178”).

  Examples of commercially available tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymers include, for example, those sold by Solvay Solexis under the trade name “Hyflon PFA” or “Hyflon MFA”; and under the trade name “Teflon PFA”. I. and those sold by diPont de Nemours & Company.

  Examples of commercially available vinyl fluoride fluoropolymers include E.I. I. Such vinyl fluoride homopolymers sold by du Pont de Nemours & Company (Wilmington, Del.).

  Examples of commercially available (TFE / P) polymers include the trade name “AFLAS” (eg, “AFLAS TFE ELASTOMER FA 100H”, “AFLAS TFE ELASTOMER FA 150C”, “AFLAS TFE ELASTOMER FA 150L”, or “AFLAS TEL”. FA 150P ") (sold by Dyneon, LLC), or trade name" VITON "(eg," VITON VTR-7480 "or" VITON VTR-7512 ") (EI du Pont de Nemours & Company (sold by Wilmington, Del.).

  Examples of commercially available ETFE polymers include, for example, the trade name “DYNEON FLUOROTHERMOPLASTIC ET 6210J”, “DYNEON FLUOROTHERMOPLASTIC ET 6235”, or “DYNEON FLUOROTHERMOPLASTIC ET 6240J” sold by Ly under the trade name “Dyon FLUOROTOTHERMOPLASTIC ET 6240J”.

  Examples of commercially available ECTFE polymers include the trade names Halar 350 and Halar 500 resins, Solvay Solexis Corp. Can be listed.

  Alternatively, the polymer matrix material of the present invention may comprise a thermoplastic or thermosetting polymer other than a fluoropolymer. Suitable alternative polymer matrix materials include polyolefins and copolymers thereof (eg, polyethylene, polypropylene, polyethylene, polymethylpentene, and polybutadiene), epoxy resins, phenolic resins, cyanate esters, polyesters, polyamides, polycarbonates, polyimides, poly Acrylic resin, polymethacrylic resin, thermoplastic olefin, ethylene vinyl alcohol (EVOH), ethylene vinyl acetate (EVA), ethylene methacrylate (EMA) thermoplastic urethane, thermoplastic silicone, ionomer, ethyl butyl acrylate (EBA), polyvinyl butyral ( PVB), ethylene propylene diene M class rubber (EPDM) or mixtures thereof.

  The particulate filler material of the present invention can comprise any organic or inorganic particulate material. The terms “microparticle” and “particle”, as used herein, are intended to encompass fibers and flakes. Suitable inorganic filler materials include, for example, glass particles, ceramic particles, metal particles, carbon particles and mineral particles. Specific examples of suitable particles and flakes include glass beads, glass microspheres, glass fibers, silica particles, carbon black, titanium dioxide particles, iron oxide particles, aluminum particles and barium titanate particles. Silica particles, particularly amorphous quartz glass particles and silica particles prepared by a sol-gel method, and glass particles can be applied to a dielectric layer of a laminated electric circuit that requires a low dielectric constant, for example.

  The shape of the filler particles, the size of the filler particles and the size distribution of the filler particles can be important parameters for characterization of the particle-filled composite article of the present invention. For example, platelet-shaped pigments can cause light interference and other optical effects. Such particles include mica-coated iron or other metal oxide complexes (eg, Taizhu TZ2013 violet from Wenzhou Pearlescent Pigments Co (Taizhu, China); and XiralTNT 60 from Merck KGaA (Darmstadt, Germany). Crystal Silver).

  In one embodiment of the invention, all particles of the particulate filler exhibit a diameter of less than about 10 microns (μm).

  In an alternative preferred embodiment of the present invention, none of the filler particles exhibits any single linear dimension greater than about 10 μm.

  In another embodiment, the particulate filler particles comprise a number of particles exhibiting a single linear dimension greater than 10 μm. The proportion of particles exhibiting a single linear dimension greater than 10 μm to particles having a single linear dimension of less than 10 μm is 0.01% to about 50%, about 0.1% to about 20%, or about 1% of the total amount of particles Can be ~ 10%. The linear dimension can be about 11 μm to about 50 μm, about 15 μm to about 20.

  As noted above, it has been surprising that it has been found that the incorporation of particles exhibiting a single linear dimension greater than 10 μm can help impart unique properties to the final film. These properties include increased tensile strength, higher opacity (as compared to those without larger particles), or reduced moisture permeability.

  Also, the particles need not be spherical. In one embodiment, the particles can be elliptical particles, also known in the art as “platelets”.

  In one embodiment of the invention, the filler particles are all substantially spherical.

  In yet another aspect of the invention, the filler particles of the film are not uniform in size. The use of non-uniformly sized particles can provide an unexpected advantage in light scattering and can provide a more uniform particle distribution. Generally, the particles are of an average particle size between about 0.1 μm and about 20 μm, and approximately 80% of the particles have a narrow particle size range between about 0.2 μm and about 5 μm.

The particulate filler material may improve moisture resistance, particle dispersibility, matrix adhesion or IR reflectivity, UV resistance, and / or mechanical properties of the composite film of the present invention. It can be treated with a surface treatment. For example, certain of the TiO ₂ forms is passivated, otherwise, they are photocatalytic.

  Suitable hydrophobic coatings useful for treating the particles of the present invention may include any coating material that is thermally stable, exhibits low surface energy, and improves the moisture resistance of the composite material of the present invention. . Suitable coating materials include conventional silane coatings, titanate coatings and zirconate coatings.

  The polymer matrix material of the present invention is mixed with the first carrier liquid. This mixture can be a dispersion of polymer particles in a first carrier liquid, a dispersion of polymer or polymer monomer or oligomer precursor droplets (ie, an emulsion) in a first carrier liquid, or a first carrier. A solution of the polymer in the liquid may be included.

  The selection of the first carrier liquid is based on the specific polymer matrix material and the form in which the polymer matrix material is introduced into the casting composition of the present invention. If a solution is desired, the solvent for the particular polymer matrix material is selected as the carrier liquid. Suitable carriers include, for example, DMAC, NMP, cellosolve, or water. If a dispersion is desired, preferred carriers are those in which the matrix material is not soluble. An aqueous solution would be a suitable carrier liquid for the dispersion of fluoropolymer particles.

  The dispersion of particulate filler of the present invention can be in a suitable second carrier liquid in which the filler is not soluble.

  A surfactant can be used to prepare the dispersion in an amount effective to alter the surface tension of the second carrier liquid so that the second carrier liquid can wet the filler particles. Suitable surfactant compounds include ionic surfactants, amphoteric, cationic and nonionic surfactants.

  In one exemplary embodiment, a mixture of a polymer matrix material and a first carrier liquid and a dispersion of filler particles in a second carrier liquid are combined to form a casting composition. Generally, the casting composition comprises between about 10 and about 90 weight percent solids (based on particles and polymer matrix), between about 20 and about 70 weight percent solids, or between about 25 and about 50 weight percent. Having solids between weight percent.

  The viscosity of the casting composition of the present invention can be adjusted by adding a suitable viscosity modifier. Such modifiers include polyacrylic acid compounds, plant gums and cellulose based compounds. Specific examples of suitable viscosity modifiers include polyacrylic acid, methylcellulose, polyethylene oxide, guar gum, locust bean gum, sodium carboxymethylcellulose, sodium alginate and tragacanth gum.

  Generally, the casting composition comprises between about 10 and about 90 weight percent solids (based on particles and / or polymers), between about 20 and about 70 weight percent solids, or about 25 to about Having between 50 weight percent solids.

  Generally, the particulate filler material may be present in the castable polymer layer in the range of about 0% to about 60% by volume.

  In one embodiment, the particulate filler is present from about 2% to about 50%, such as from about 8% to about 25% by volume based on the total volume of the multilayer film. In another embodiment, the particulate filler is present from about 9% to about 15% by volume based on the total volume of the multilayer film. It should be understood that subranges falling within the range of 0% to about 60% are encompassed herein. This subrange also includes fractional ranges such as about 0.5% to about 5.5%, about 0.6% to about 10.3%. All ranges are encompassed herein. The recitation of numerical ranges by endpoints includes all numbers subsumed within that range (eg 1 to 5 is 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.) including).

  The viscosity of the casting composition of the present invention can be adjusted by adding a suitable viscosity modifier. Such modifiers include polyacrylic acid compounds, plant gums and cellulose based compounds. Specific examples of suitable viscosity modifiers include polyacrylic acid, methylcellulose, polyethylene oxide, guar gum, locust bean gum, sodium carboxymethylcellulose, sodium alginate and tragacanth gum.

  To prepare a film, a layer of the composition is cast on a support by conventional methods (eg, dip coating, reverse roll coating, knife over roll, knife over plate, and metering rod coating). Is done.

  Suitable support materials include, for example, metal films, polymer films, or ceramic films. Specific examples of suitable supports include stainless steel foil, polyimide film, polycarbonate film, titanium, aluminum or fluoropolymer film.

  In one exemplary casting method, the film is as detailed in US Pat. No. 4,883,716, the contents of which is hereby incorporated by reference in its entirety. Formed by casting on a carrier belt having a low thermal mass. This carrier belt is part of the casting apparatus. The carrier belt is dipped through the fluoropolymer matrix material / specific filler material dispersion in the dipping bath at the base of the casting tower so that a coating of the dispersion forms on the carrier belt. The coated carrier belt then passes through a metering zone where a metering bar removes excess dispersion from the coated carrier belt. Following this metering zone, the coated carrier belt proceeds to a drying zone maintained at a temperature sufficient to remove the carrier liquid from the dispersion into a dry film. The carrier belt with the dried film then proceeds to a baking / fusion zone where the temperature is sufficient to unite or fuse the fluoropolymer and the microparticles in the dispersion. Finally, the carrier belt can pass through the cooling plenum, from where it can be directed to the next dipping bath to initiate the formation of a further layer of the next film, or directed to a peeling device. This process can be repeated as many times as desired, typically up to 7 layers (eg, 3 layers are fluoropolymer matrix / specific filler material layers and 2 layers are from one or more fluoropolymers). The outer layer is 5 layers).

  In a further exemplary casting method, the coated film can remain on the carrier support so that a composite structure of support and cast film results. Examples of this may include fluoropolymer and polyimide supports, aluminum supports, titanium supports, steel supports or polycarbonate supports. In a further example, a separate support film may be introduced between the applied casting composition and the carrier belt such that a castable fluoropolymer film is deposited on the support. In one example, a support, polyimide film, aluminum sheet, titanium sheet, steel sheet, or polycarbonate film may be supported on a carrier belt and the casting composition may be applied to the support. Thus, the casting composition can be applied to both sides of the support such that the top and bottom surfaces of the support are coated. Suitable structures include, for example, a first castable fluoropolymer / aluminum / second castable fluoropolymer that can be the same as or different from the first castable fluoropolymer (eg, PTFE / Al / PTFE). ), A first castable fluoropolymer / polyimide / second castable fluoropolymer (eg, FEP / polyimide / FEP) and a first cast, which may be the same as or different from the first castable fluoropolymer. A second castable fluoropolymer (eg, PVDF / polycarbonate / PVDF) that may be the same or different from the possible fluoropolymer / polycarbonate / first castable fluoropolymer.

  Other alternative support films may be used depending on the processing temperature required for the deposited fluoropolymer casting composition. For fluoropolymer compositions having lower melting temperatures, lower temperature supports can be used.

  In one example, to provide a film of polymer matrix material and particulate filler, the carrier liquid and processing aids (eg, surfactants and / or viscosity modifiers) are removed by evaporation and / or by pyrolysis. Removed from the casting layer. In one embodiment, the particulate-filled polymer matrix composite film of the present invention is prepared by heating a cast film to evaporate the carrier liquid.

  The film of polymer matrix material and particulate filler can be further heated to alter the physical properties of the film. This can include post-curing of the film.

  In one embodiment, the multilayer film has three layers. The first outer layer is a castable fluoropolymer, the second intermediate layer is a castable fluoropolymer comprising a particulate filler as described herein, and the third outer layer is a flowable. It is a ductile fluoropolymer. In another embodiment, either or both of the first and third outer layers may comprise from about 0.01% to about 12%, especially from about 0.01% to about 6% by volume of particulate filler. .

  In another aspect, a fourth layer can be disposed on the first layer. This fourth layer is a castable fluoropolymer as described herein. In yet another aspect, the fifth layer can be disposed on the third layer. This fifth layer is a castable fluoropolymer as described herein. Ideally, the fourth and fifth layers are selected from tetrafluoroethylene-perfluoro (alkyl vinyl ether) (PFA) copolymers or fluorinated ethylene propylene copolymers (FEP) or mixtures thereof. Furthermore, the fourth and / or fifth layer may include a mixture of PTFE and PFA or FEP.

  The fourth and fifth layers can further include certain fillers as described herein. Either or both of the fourth and fifth outer layers may comprise from about 0.01% to about 12%, in particular from about 0.01% to about 6% by volume particulate filler.

  In one embodiment, the outer layer of the multilayer film can be made from a melt-bondable fluoropolymer. Suitable melt bondable materials include, for example, tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymers or fluorinated ethylene propylene copolymers (FEP) or mixtures thereof.

  The method of the present invention provides a film having a thickness of less than about 2 mils, and even less than about 1 mils, so as to be economically manufactured. In this specification, the film thickness is indicated by “mil”. One mil is equal to 0.001 inch.

  In yet another aspect, the multilayer film of the present invention has a total thickness between about 0.6 mils and about 2 mils, more specifically between about 0.8 mils and about 1.5 mils.

  In one embodiment, the multilayer film of the present invention has a breakdown strength (kV) greater than 3 kV as measured by ASTM method D3755. Specifically, the breakdown strength is greater than 3 kV to about 12 kV, about 3 kV to about 7 kV, and particularly about 4 kV to about 6 kV.

  The strength of dielectric breakdown is determined by the standard test method for dielectric breakdown voltage and dielectric strength of solid electrical insulation materials under the direct voltage stress of ASTM D3755 (Standard Test Method for Dielectric Strength of Electric Strength and Dielectric Strength of Dielectric Strength). -Measured according to -Voltage Stress).

  A 5 inch by 5 inch specimen is held in an air medium between two opposing cylinders 2 inches in diameter and 1 inch in length, with ends rounded to a radius of 0.25 inches. The test piece is electrically stressed by the application of a DC voltage that rises at a constant rate of 500 V / sec until internal failure occurs. Dielectric breakdown generally involves an increase in current in a test circuit that can activate a sensing element (eg, a circuit breaker or fuse). The test voltage at the time of destruction is recorded.

  In another embodiment, the multilayer film has a solar reflectance greater than 70% as measured by ASTM method E424 on at least one side of the film. Specifically, the solar reflectance on at least one side of the film is greater than 70% to about 99.9%, about 75% to about 99%, particularly about 80% to about 99%.

  Solar reflectance is measured according to Standard Test Methods for Solar Energy Transmission and Reflection (Territorial) of the standard for solar energy transmittance and reflectance (on the earth) of ASTM E424 sheet material. The The standard procedure of ASTM E424 requires data collection over the 350-2100 nm range. A summary for the 400-1100 nm data is a commonly used variation of this procedure and the method used herein.

  An integrating sphere spectrophotometer is used to measure the spectral characteristics of a 2 inch by 2 inch specimen over the spectral region of interest. Smoked magnesium oxide is used as a standard for fully reflective and diffuse surfaces. Spectral transmittance data for air and directional spectral reflectance data for magnesium oxide are obtained. Solar transmittance and reflectance (in percent) are calculated by integrating the spectral reflectance over the standard solar energy distribution. While solar transmittance is measured through the film, reflectance is generally measured on one side of the film. Opacity (%) is defined as 100%-% transmittance.

In yet another embodiment, the multilayer film has a moisture vapor transmission rate measured by ASTM method F1249 of less than about 20 g / m ² / day. Specifically, the moisture permeability is less than about 16 g / m ² / day, more specifically about 13 g / m ² / day, and most specifically less than about 8 g / m ² / day.

  Moisture permeability is measured according to Water Vapor Transmission Rate Through Plastic Film and Heating a Modulated Infrared Sensor through plastic film and sheet material using ASTM F1249 modulated infrared sensor.

  A 4 inch × 4 inch specimen is tightly sealed with grease and O-ring between the drying and wetting chambers. Water vapor diffusing through the film mixes with the nitrogen gas in the drying chamber and is carried to the pressure modulated infrared sensor. This sensor measures the portion of infrared energy absorbed by water vapor and generates an electrical signal, the magnitude of which is proportional to the water vapor concentration. The magnitude of this electrical signal is compared to that of a known moisture permeability calibration film, and from this comparison the rate at which moisture penetrates the test film is calculated. This test is performed at a constant humidity (eg, 39 ° C. and 100% relative humidity). In yet another embodiment, the multilayer film has a light opacity greater than about 80% as measured by ASTM method E424. Specifically, this light opacity is greater than about 80, more specifically greater than about 85, and most specifically greater than about 95.

In certain embodiments, the multilayer film described herein is 3 kV as measured by ASTM method D3755 when the multilayer film has a thickness between about 0.7 mil and about 2.0 mil. Greater breakdown strength (kV), solar reflectance greater than 70% as measured by ASTM method E424, moisture permeability less than 20 g / m ² / day as measured by ASTM method F1249.

  In another embodiment, the multilayer film has different properties. For example, the multilayer film may have a white highly reflective surface on one side and a dark surface on the other side. In another example, the multilayer film may have a white, highly reflective surface on one side and a dark, non-reflective surface on the other side. In another embodiment, the multilayer film may have a white highly reflective surface on one side and a dark reflective surface on the other side.

The color of either side of the film can be shown by measuring the color using a standard method called the CIE L ^* a ^* b color model. In one particular embodiment of a double-sided color film, a black surface and a white surface may be distinguished. Low values of L ^* indicates darker color, L * ^{= 0} is the most extreme black value. L ^* high values indicate a whiter ^color, L * = 100 is the maximum diffuse white measurements.

  The fluoropolymers specifically used for the outer layers of the multilayer films described herein have significantly different properties (eg, high transparency, good dielectric strength, high purity, chemical inertness, low coefficient of friction, high thermal stability) Property, excellent weather resistance, and UV resistance), it is a unique material. Fluoropolymers are often used in applications requiring high performance, often requiring a combination of the above properties. However, because of their low surface energy, fluoropolymers are difficult to wet with many, if not all, non-fluoropolymer materials, liquid or solid.

  As a result, a common problem faced by fluoropolymers is that they are difficult to adhere to non-fluoropolymer surfaces. Furthermore, this problem is particularly troublesome for fluoropolymer composite laminates in which at least one layer is not a fluoropolymer.

  The present invention provides a novel multilayer film and a method of preparing the multilayer film by using suitable materials for multiple layer multiple deposition followed by further optional surface treatment. In general, the multilayer film of the present invention comprises an outer layer comprising a modified fluoropolymer and one or more interlayers described herein having a polymer matrix / particulate film.

  The term “modified fluoropolymer” is intended to include fluoropolymers that are bulk modified, surface modified, or both. Bulk fluoropolymer modifications include the inclusion of polar functional groups contained in or grafted to or onto the fluoropolymer backbone. This type of modified fluoropolymer material can be used in combination with unmodified fluoropolymer layers and non-fluoropolymer layers, or as a base fluoropolymer layer. For example, maleic anhydride modified ETFE is suitable for bonding nylon to an untreated ETFE support.

  Surface modification of fluoropolymers is another way of providing modified fluoropolymers useful in the present invention. In general, polar functional groups are attached to the fluoropolymer surface, making it more wettable and providing an opportunity for chemical bonding. There are several ways to functionalize the fluoropolymer surface, including chemical etching, physical-mechanical etching, plasma etching, corona treatment, chemical vapor deposition, or any combination thereof. In one embodiment, the chemical etch includes sodium ammonia or sodium naphthalene. Exemplary physical-mechanical etching may include sandblasting and air abrasion with silica. In another embodiment, the plasma etch includes a reactive plasma (eg, hydrogen, oxygen, acetylene, methane, and their mixtures with nitrogen, argon, and helium). Corona treatment involves reactive hydrocarbon vapors (eg, ketones (eg, acetone), alcohols, p-chlorostyrene, acrylonitrile, propylene diamine, anhydrous ammonia, styrene sulfonic acid, carbon tetrachloride, tetraethylenepentamine, cyclohexylamine, Tetraisopropyl titanate, decylamine, tetrahydrofuran, diethylenetriamine, tert-butylamine, ethylenediamine, toluene-2,4-diisocyanate, glycidyl methacrylate, triethylenetetramine, hexane, triethylamine, methyl alcohol, vinyl acetate, methyl isopropylamine, vinyl butyl ether, methacryl Acid methyl, 2-vinyl pyrrolidone, methyl vinyl ketone, xylene or mixtures thereof).

  Some techniques use a combination of steps including one of these methods. For example, surface activation can be achieved by plasma or corona discharge in the presence of excited gas species. For example, surface activation can be achieved by corona treatment in the presence of a solvent gas (eg, acetone).

  While not being limited by theory, it has been found that this method provides a strong interlayer adhesion between the modified fluoropolymer and the non-fluoropolymer interface (or second modified fluoropolymer). In one method, the fluoropolymer and non-fluoropolymer forms are each formed separately. Subsequently, fluoropolymer forms are disclosed in U.S. Pat. Nos. 3,030,290, 3,255,099, 3,274,089, 3,274,090, 3,274,091, and 3,275,540. No. 3,284,331, No. 3291712, No. 3296011, No. 3339114, No. 3397132, No. 3485734, No. 3507763 Nos. 3,676,181, 4,499,921, and 6,726,979 (the teachings of these patent documents are incorporated herein in their entirety for all purposes). The surface treatment is performed by the treatment method described in (1). The resulting modified fluoropolymer and non-fluoropolymer forms are then contacted with each other, for example by thermal lamination, to form a multilayer film. Finally, the multilayer film can be subjected to ultraviolet light having a wavelength in the UVA; UVB and / or UVC range.

  In one embodiment, the surface of the fluoropolymer support is treated with a corona discharge in which the electrode area is filled with acetone, tetrahydrofuran methyl ethyl ketone, ethyl acetate, isopropyl acetate or propyl acetate vapor.

  A corona discharge is generated by capacitive exchange of a gas medium that is located between two electrodes that are spaced apart and at least one of which is insulated from the gas medium by a dielectric barrier. Corona discharge is inherently somewhat limited to alternating current due to its capacitive nature. Corona discharge is a high voltage, low current phenomenon where voltage is typically measured in kilowatts and current is typically measured in milliamps. Corona discharge may be maintained over a wide range of pressures and frequencies. In general, a pressure of 0.2 to 10 atmospheres defines the limit of corona discharge work, and generally atmospheric pressure is preferred. A frequency in the range of 20 Hz to 100 MHz can be conveniently used. Specifically, the range is from 500 Hz to 3000 Hz to 10 MHz.

  The corona discharge phenomenon when a dielectric barrier is used to insulate each of two spaced apart electrodes from the gas medium is often referred to as an electrodeless discharge, while a single dielectric barrier is The resulting corona discharge when only one of those electrodes is used to insulate from the gas medium is often referred to as a semi-corona discharge. The term “corona discharge” is used throughout this specification to refer to both types of corona discharges (ie, both electrodeless and semi-corona discharges).

  For details on the corona discharge treatment procedure, see E.C. I. U.S. Pat. No. 3,676,181 provided in a series of U.S. patents assigned to du Pont de Nemours and Company (USA), and U.S. Pat. No. 6, Saint-Gobain Performance Plastics Corporation. No. 726,979, the teachings of these patent documents are hereby incorporated by reference in their entirety for all purposes. One example of a proposed technique can be found in US Pat. No. 3,676,181 (Kowalski). The atmosphere of the sealed processing unit is 20% (volume) acetone in nitrogen and continuous. For example, the outer layer of a continuously supplied multilayer film or particulate-filled film is subjected to between 0.15 watt hours and 2.5 watt hours per square foot of film / sheet surface. The fluoropolymer can be treated to enhance adhesion on both sides of the film / form. This material can then be placed on a non-siliconized release liner for storage. The C-treated material will last longer than one year without significant loss of surface wettability, cementability, and adhesion.

  In another aspect, the surface of the fluoropolymer support is treated with a plasma. The phrase “plasma enhanced chemical vapor deposition” (PECVD) is known in the art and refers to a method in which a thin film is deposited from a gaseous state (vapor) to a solid state on a support. There are several chemical reactions involved in this method, which take place after the generation of a plasma of reactive gases. The plasma is generally generated by RF (AC) frequency or DC discharge between two electrodes, on which a support is placed and whose space is filled with a reactive gas. A plasma is any gas in which a significant percentage of atoms or molecules are ionized, resulting in reactive ions, electrons, radicals and ultraviolet radiation.

  In another exemplary embodiment, at least one major surface of the fluoropolymer layer comprises colloidal silica. The colloidal silica is typically present in the solution in an amount that provides adhesion between the first and second layers. In one embodiment, the colloidal silica is present in a solution that does not adversely affect the adhesion of the colloidal silica. In one example, the solution may be aqueous. A commercially available colloidal silica solution is available as Ludox®. In one embodiment, a binding solution may be used in addition to the colloidal silica solution. Any known binding solution that is compatible with colloidal silica is contemplated. For example, a binding fluoropolymer (eg, FEP or PFA) may be used. Typically, the binding solution and colloidal silica are in a ratio of at least about 25/75 by weight (eg, about 40/60 by weight, eg, about 50/50 by weight, or even about 75/25 by weight). Applied.

  The multilayer film of the present invention can be used to protect electronic components in particular from moisture, weather, heat, radiation, physical damage and / or to insulate such components. Examples of optoelectronic components include crystalline silicon based photovoltaic modules, amorphous silicon, CIGS, DSC, OPV or CdTe based thin photovoltaic modules, OLEDS, LEDs, LCD, printed circuit boards, Examples include, but are not limited to, packaging for flexible displays and printed wiring boards.

  All disclosed layers contain common compounding additives including antioxidants, UV blockers, UV stabilizers, hindered amine stabilizers, curing agents, crosslinking agents, additional pigments, processing aids, etc. May be.

The following enumerated paragraphs 1-34 define various aspects of the invention. In one embodiment, in the first paragraph (1), the present invention
A first layer comprising a fluoropolymer castable with water or a solvent and a particulate filler material;
A second layer having a top surface and a bottom surface selected from polyimide, polycarbonate, titanium, steel, or aluminum;
A multilayer film comprising a fluoropolymer castable with water or a solvent and a third layer comprising a particulate filler material, the first layer being disposed on top of the second layer, Provides a multilayer film disposed on the bottom surface of the second layer.

  2. Each of the fluoropolymers is independently polytetrafluoroethylene, polyvinylidene fluoride, polychlorotrifluoroethylene, polyvinyl fluoride, tetrafluoroethylene / hexafluoropropylene / ethylene copolymer, chlorotrifluoroethylene / vinylidene fluoride copolymer, chloro Trifluoroethylene / hexafluoropropylene, chlorotrifluoroethylene / ethylene copolymer, ethylene / trifluoroethylene copolymer, ethylene / tetrafluoroethylene copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer or A multilayer film according to paragraph 1 selected from mixtures thereof.

  3. The fine particle fillers are independently silica particles, glass beads, glass microspheres, glass fibers, titanium dioxide particles, barium titanate particles, calcium carbonate, zinc oxide, mica, clay, talc, iron oxide, carbon black, Paragraph 1 or 2 selected from zinc sulfide, barium sulfate, zinc sulfite, cobalt aluminate blue, sodium aluminosulfosilicate, magnesium hydroxide, antimony trioxide, organophosphate compound, brominated compound or mixtures thereof. The multilayer film in any one.

  4). The fluoropolymers are each independently polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer (PFA), ethylene / tetrafluoroethylene copolymer (ETFE), fluorinated ethylene propylene copolymer (FEP), A multilayer according to any one of paragraphs 1 to 3, wherein the multilayer filler is selected from polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE) or mixtures thereof, and the particulate filler of the fluoropolymer layer is titanium dioxide the film.

  5). A multilayer film according to any one of paragraphs 1 to 4, wherein the dielectric breakdown strength (kV) is greater than 3 kV as measured by ASTM method D3755.

  6). A multilayer film according to any one of paragraphs 1 to 5, wherein the solar reflectance is higher than 70% as measured by ASTM method E424.

7). The multilayer film according to the moisture permeability is less than about 20 g / ^{m 2} / day as measured by ASTM method F1249, any one of paragraphs 1 to 6.

  8). An optoelectronic device comprising an optoelectronic component and the multilayer film according to any one of paragraphs 1-7, wherein the optoelectronic component and the multilayer film are packaged together.

  9. 9. The optoelectronic device according to paragraph 8, wherein the multilayer film is a backsheet for optoelectronic components.

10. A first layer comprising a fluoropolymer castable with water or a solvent and a particulate filler material;
A multilayer film comprising a second layer having a top surface and a bottom surface selected from polyimide, polycarbonate, titanium, steel, or aluminum, wherein the first layer is disposed on one side of the second layer; Multilayer film.

  11. Fluoropolymer is polytetrafluoroethylene, polyvinylidene fluoride, polychlorotrifluoroethylene, polyvinyl fluoride, tetrafluoroethylene / hexafluoropropylene / ethylene copolymer, chlorotrifluoroethylene / vinylidene fluoride copolymer, chlorotrifluoroethylene / hexa Selected from fluoropropylene, chlorotrifluoroethylene / ethylene copolymer, ethylene / trifluoroethylene copolymer, ethylene / tetrafluoroethylene copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer or mixtures thereof A multilayer film according to paragraph 10, wherein

  12 Fine particle filler is silica particles, glass beads, glass microspheres, glass fibers, titanium dioxide particles, barium titanate particles, calcium carbonate, zinc oxide, mica, clay, talc, iron oxide, carbon black, zinc sulfide, barium sulfate. Paragraph 10 or 11, selected from zinc sulfite, cobalt aluminate blue, sodium aluminosulfosilicate, magnesium hydroxide, antimony trioxide, organophosphate compound, brominated compound or mixtures thereof. Multilayer film.

  13. Fluoropolymers include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer (PFA), ethylene / tetrafluoroethylene copolymer (ETFE), fluorinated ethylene propylene copolymer (FEP), polyvinylidene fluoride (PVDF) ), Polychlorotrifluoroethylene (PCTFE), or mixtures thereof, and the particulate filler of the fluoropolymer layer is titanium dioxide, any one of paragraphs 10-12.

  14 A multilayer film according to any one of paragraphs 10 to 13, wherein the dielectric breakdown strength (kV) is greater than 3 kV as measured by ASTM method D3755.

  15. A multilayer film according to any one of paragraphs 10 to 14, wherein the solar reflectance is higher than 70% as measured by ASTM method E424.

16. The multilayer film according to any one of paragraphs 10 to 15, wherein the moisture permeability is less than about 20 g / m < ² > / day as measured by ASTM method F1249.

  17. An optoelectronic device comprising an optoelectronic component and the multilayer film according to any one of paragraphs 10-16, wherein the optoelectronic component and the multilayer film are packaged together.

  18. 18. An optoelectronic device according to paragraph 17, wherein the multilayer film is a backsheet for optoelectronic components.

19. Applying a casting composition onto a support of polyimide, polycarbonate, titanium, steel, or aluminum, wherein the casting composition comprises:
Career,
A method of preparing a multilayer film comprising a step comprising a fluoropolymer castable with water or a solvent and a particulate filler material.

  20. 20. The method of paragraph 19 further comprising the step of drying the multilayer film.

  21. Fluoropolymer is polytetrafluoroethylene, polyvinylidene fluoride, polychlorotrifluoroethylene, polyvinyl fluoride, tetrafluoroethylene / hexafluoropropylene / ethylene copolymer, chlorotrifluoroethylene / vinylidene fluoride copolymer, chlorotrifluoroethylene / hexa Selected from fluoropropylene, chlorotrifluoroethylene / ethylene copolymer, ethylene / trifluoroethylene copolymer, ethylene / tetrafluoroethylene copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer or mixtures thereof 21. The method of any of paragraphs 19 or 20, wherein

  22. Fine particle filler is silica particles, glass beads, glass microspheres, glass fibers, titanium dioxide particles, barium titanate particles, calcium carbonate, zinc oxide, mica, clay, talc, iron oxide, carbon black, zinc sulfide, barium sulfate. In any one of paragraphs 19 to 21, selected from zinc sulfite, cobalt blue aluminate, sodium aluminosulfosilicate, magnesium hydroxide, antimony trioxide, organophosphate compounds, brominated compounds or mixtures thereof The method described.

  23. Fluoropolymers include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer (PFA), ethylene / tetrafluoroethylene copolymer (ETFE), fluorinated ethylene propylene copolymer (FEP), polyvinylidene fluoride (PVDF) ), Polychlorotrifluoroethylene (PCTFE) or mixtures thereof, and the particulate filler of the fluoropolymer layer is titanium dioxide, according to any one of paragraphs 19-22.

  24. 24. The method of any one of paragraphs 19-23, wherein the breakdown strength (kV) is greater than 3 kV as measured by ASTM method D3755.

  25. 25. A method according to any one of paragraphs 19-24, wherein the solar reflectance is higher than 70% as measured by ASTM method E424.

26. 26. A method according to any one of paragraphs 19 to 25, wherein the moisture permeability is less than about 20 g / m < ² > / day as measured by ASTM method F1249.

27. Applying a first casting composition to an upper surface of a polyimide, polycarbonate, titanium, steel, or aluminum support, wherein the first casting composition comprises:
Career,
A process comprising a fluoropolymer castable with water or a solvent and a particulate filler material;
Applying a second casting composition to the bottom surface of a polyimide, polycarbonate, titanium, steel, or aluminum support, wherein the second casting composition comprises:
Career,
A process comprising the steps of: containing a fluoropolymer castable with water or a solvent; and a particulate filler material.

  28. 28. The method of paragraph 27, further comprising the step of drying the multilayer film.

  29. Each of the fluoropolymers is independently polytetrafluoroethylene, polyvinylidene fluoride, polychlorotrifluoroethylene, polyvinyl fluoride, tetrafluoroethylene / hexafluoropropylene / ethylene copolymer, chlorotrifluoroethylene / vinylidene fluoride copolymer, chloro Trifluoroethylene / hexafluoropropylene, chlorotrifluoroethylene / ethylene copolymer, ethylene / trifluoroethylene copolymer, ethylene / tetrafluoroethylene copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer or 29. A method according to any of paragraphs 27 or 28, selected from mixtures thereof

  30. The fine particle fillers are independently silica particles, glass beads, glass microspheres, glass fibers, titanium dioxide particles, barium titanate particles, calcium carbonate, zinc oxide, mica, clay, talc, iron oxide, carbon black, Paragraphs 27-29 selected from zinc sulfide, barium sulfate, zinc sulfite, cobalt aluminate blue, sodium aluminosulfosilicate, magnesium hydroxide, antimony trioxide, organophosphate compounds, brominated compounds or mixtures thereof. The method according to any one of the above.

  31. The fluoropolymers are each independently polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer (PFA), ethylene / tetrafluoroethylene copolymer (ETFE), fluorinated ethylene propylene copolymer (FEP), The method according to any one of paragraphs 27-30, selected from polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE) or mixtures thereof, wherein the particulate filler of the fluoropolymer layer is titanium dioxide. .

  32. 32. A method according to any one of paragraphs 27-31, wherein the breakdown strength (kV) is greater than 3 kV as measured by ASTM method D3755.

  33. The method according to any one of paragraphs 27-32, wherein the solar reflectance is higher than 70% as measured by ASTM method E424.

34. 34. A method according to any one of paragraphs 27-33, wherein the moisture permeability is less than about 20 g / m < ² > / day as measured by ASTM method F1249.

  The multilayer films shown in paragraphs 1-34 above provide certain advantages that are generally not found in other multilayer films. For example, inclusion of a polyimide layer serves as a good dielectric insulator because it has a nominal breakdown strength of about 7000 vpm. Polyimide materials also provide excellent thermal stability, good mechanical properties, radiation resistance and excellent chemical resistance.

  Bond integrity between two dissimilar materials by applying a fluoropolymer directly on a polyimide, polycarbonate, aluminum, titanium or steel film offers advantages over laminated structures. For example, a coated multilayer film does not exhibit voids or bubbles between layers that can cause delamination or can cause electrical weak points that can cause partial discharges. A combination of different fluoropolymers (on one or both sides of a support (eg polyimide, polycarbonate, aluminum, titanium or steel)) using multiple dip coating methods to impart the desired properties to the final multilayer film Can be adjusted. Furthermore, as noted above, particulates can be added to provide an opaque film that provides improved reflectivity and overall efficiency of the photovoltaic module. The particulate material can be applied during the application process as part of a fluoropolymer casting composition, or it can be applied later with a high temperature highly colored coating (eg, as described on a bar code label).

  The invention will be further described with reference to the following non-limiting examples. It will be apparent to those skilled in the art that many changes can be made in the embodiments described without departing from the scope of the invention. Therefore, the scope of the present invention should not be limited to the embodiments described in this application, but only by the embodiments described by the language of the claims and the equivalents of those embodiments. It is. Unless otherwise specified, all percentages are by weight.

Casting Fluoropolymer Film Preparation General Procedures for Film Casting (a) Aqueous dispersions can be prepared with organic or inorganic fillers (eg, white pigments (TiO ₂ , ZnO or others described herein) Of the pigments)).

  (B) An aqueous dispersion is prepared comprising a film-forming polymeric material (especially a fluoropolymer) selected from any of those described throughout this specification. This dispersion may contain the aqueous dispersion described in step (a).

  (C) The carrier belt can then be dipped through the dispersion described in step (b) such that a coating of the dispersion is formed on the carrier belt.

  (D) Pass the coated carrier belt through the metering zone to remove excess dispersion.

  (E) Dry the weighed coated carrier to remove water from the dispersion.

  (F) The dried coated carrier is then heated to a temperature sufficient to consolidate the dispersion. Here, the carrier belt has a low heat capacity with chemical and dimensional stability at the compaction temperature of the dispersion and a work of adhesion between the carrier belt and the dispersion that does not exceed the yield strength of the compacted fluoropolymer film. It is made of material.

  (G) Step (c) to step (f) can be repeated to cast a multilayer film, if necessary. At least one of the dispersion coatings contains the dispersion described in step (a) or (b).

  (H) Optionally, peel the film from the carrier (eg, polyimide).

  (I) Optionally, the multilayer film can be C-treated on one or both sides, or otherwise treated so that its surfaces can be bonded.

Dispersion:
PTFE dispersion containing 22 volume% TiO ₂ 3,384 g PTFE dispersion (Daikin, 59% solids), 1,772 g TiO ₂ slurry (DuPont R-900 TiO ₂ , 60% solids) and 1,400 Of deionized water is mixed for 30 minutes. To this mixture is added 32 g modified fluoroalkyl surfactant (Ciba, 60% solids) and mixed for an additional 10 minutes. This solution is filtered through a 10 micron sieve.

PTFE Dispersion Containing 14.8% by Volume TiO ₂ 3,000 g PTFE dispersion (Daikin, 59% solids), 990 g TiO ₂ slurry (DuPont R-900 TiO ₂ , 60% solids) Ionized water is mixed for 30 minutes. To this mixture, 24 g of modified surfactant (Ciba, 60% solids) is added and mixed for an additional 10 minutes. This solution is filtered through a 10 micron sieve.

PTFE dispersion containing 12% TiO ₂ 1,532 g PTFE dispersion (Daikin, 59% solids), 400 g TiO ₂ slurry (DuPont R-900 TiO ₂ , 60% solids) and 550 deionized water. Mix for 30 minutes. To this mixture is added 10 g modified surfactant (Ciba, 60% solids) and mixed for an additional 10 minutes. This solution is filtered through a 10 micron sieve.

PTFE dispersion containing 38% by volume TiO ₂ 3,000 g PTFE dispersion (Daikin, 60% solids), 3,440 g TiO ₂ slurry (DuPont R-900 TiO ₂ , 60% solids) and 3,500 g Of deionized water is mixed for 30 minutes. To this mixture, 50 g of modified fluoroalkyl surfactant (Ciba, 60% solids) is added and mixed for an additional 10 minutes. This solution is filtered through a 10 micron sieve.

PTFE dispersion containing 4% by volume TiO ₂ 7,659 g of PTFE dispersion (Daikin, 60% solids), 666 g of TiO ₂ slurry (DuPont R-900 TiO ₂ , 60% solids) and 1,625 g of dehydrated Ionized water is mixed for 30 minutes. To this mixture, 50 g of modified fluoroalkyl surfactant (Ciba, 60% solids) is added and mixed for an additional 10 minutes. This solution is filtered through a 10 micron sieve.

PTFE dispersion containing 41% by volume TiO ₂ 550 g PTFE dispersion (Daikin, 60% solids), 826 g TiO ₂ slurry (DuPont R-900 TiO ₂ , 60% solids) and 600 g deionized water. Mix for 30 minutes. To this mixture is added 10 g modified fluoroalkyl surfactant (Ciba, 60% solids) and 13.2 g acrylic copolymer (Rohm and Haas, 100% solids) and mixed for an additional 10 minutes. This solution is filtered through a 10 micron sieve.

PTFE dispersion containing 28% by volume TiO ₂ 3,970 g PTFE dispersion (Daikin, 60% solids), 2,870 g TiO ₂ slurry (DuPont R-900 TiO ₂ , 60% solids) and 3,110 g Of deionized water is mixed for 30 minutes. To this mixture is added 50 g modified fluoroalkyl surfactant (Ciba, 60% solids). This solution is filtered through a 10 micron sieve.

PTFE dispersion containing 3% by volume TiO ₂ 728 g PTFE dispersion (Daikin, 60% solids), 105 g TiO ₂ slurry (DuPont R-900 TiO ₂ , 60% solids) and 172 g deionized water, Mix for 30 minutes. To this mixture is added 5 g modified fluoroalkyl surfactant (Ciba, 60% solids). This solution is filtered through a 10 micron sieve.

PTFE dispersion containing 2% by volume carbon black 816 g of PTFE dispersion (Daikin, 60% solids), 33 g of carbon black slurry (TOKAI Aqua black, 30% solids) and 143 g of deionized water were mixed for 30 minutes. To do. To this mixture is added 5 g modified fluoroalkyl surfactant (Ciba, 60% solids) and 3 grams acrylic copolymer (Rohm and Haas, 100% solids). This solution is filtered through a 10 micron sieve.

Clear PTFE Dispersion Without Filler 796 g of PTFE dispersion (Daikin, 59% solids) and 157 deionized water are mixed for 30 minutes. This solution is filtered through a 10 micron sieve.

Clear PFA Dispersion Without Filler 1.480 g of PFA dispersion (DuPont, 58-62% solids) and 2520 g of deionized water are mixed for 30 minutes. To this mixture is added 10 g of modified nonionic surfactant (DuPont, 50% solids) and mixed for an additional 10 minutes. This solution is filtered through a 10 micron sieve.

Clear FEP Dispersion without Filler 1,000 g FEP dispersion (DuPont, 41% solids) and 450 g deionized water are mixed for 30 minutes. To this mixture is added 2.25 g of modified nonionic surfactant (DuPont, 50% solids) and mixed for an additional 10 minutes. This solution is filtered through a 10 micron sieve.

  The following films were prepared according to the general procedure.

Example 1
Using the general procedure and method described above, a four layer film was prepared with the following configuration.

  Total film thickness: 1.1 mil

Example 2
Using the general procedure and method described above, a five-layer film was prepared with the following configuration.

  Total film thickness: 1.1 mil

Example 3

  Total film thickness 1.1 mil

  The following characteristics were measured:

  Tedlar PV2111 is a commercial film sold by DuPont and is used in the lamination of PV backsheets. The film thickness is 1.0 mil.

  A value of dielectric strength> = 3.00 kV is generally considered appropriate for a 1 mil PV backsheet film.

Test method:
The strength of breakdown was generally measured according to ASTM D149 using a Beckman Dielectric Tester QC101A. The film was sandwiched between circular electrodes having a 0.25 inch diameter. The lamp DC voltage was then applied starting at zero volts at a constant ramp rate (typically 500 V / sec). The voltage at which film thickness burn through was observed was reported as the breakdown voltage.

  The light transmittance was measured according to ASTM E424 using a Gretag Macbeth Color-Eye (registered trademark) 7000A Spectrophotometer. The wavelength scanning range was 400 nm to 750 nm. The background correction scan was performed with the transmittance port empty and the reflectance standard in the reflectance port. The film was then mounted on the accessory's transmittance port and the% total transmittance (diffusion + regular transmittance) was measured. Opacity% = 100% -Transmittance%.

Example 4
Using the general procedure and method described above, a five-layer film was prepared with the following configuration.

Example 5
Using the general procedure and method described above, a five-layer film was prepared with the following configuration.

Example 6
Using the general procedure and method described above, a three layer film was prepared with the following configuration.

Example 7
Using the general procedure and method described above, a five-layer film was prepared with the following configuration.

Example 8
Using the general procedure and method described above, a five-layer film was prepared with the following configuration.

  Examples 4-8 were tested as follows. Standard test method for the dielectric breakdown voltage and dielectric strength of solid electrical insulation materials under the direct voltage stress of ASTM D3755 (Standard Test Method for Dielectric Strength of Electric Strength and Dielectric Strength). -Voltage Stress). Solar reflectance is measured according to Standard Test Methods for Solar Energy Transmission and Reflection (Terrestrial) of the standard for solar energy transmission and reflectance (on the earth) of ASTM E424 sheet material. did. Moisture permeability was measured according to the Water Vapor Transmission Rate Through Thrust Filming and Modulated Infrared Sensor through plastic film and sheet materials using ASTM F1249 modulated infrared sensor. And the opacity was measured according to ASTM method E424.

  Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. All references cited throughout this specification, including those in the background art, are hereby incorporated by reference in their entirety. Those skilled in the art will recognize, or at best be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention specifically described herein. Such equivalents are intended to be encompassed by the scope of the following claims.

Claims (34)

A first layer comprising a fluoropolymer castable with water or a solvent and a particulate filler material;
A second layer having a top surface and a bottom surface selected from polyimide, polycarbonate, titanium, steel or aluminum;
A multilayer film comprising a fluoropolymer castable with water or a solvent and a third layer comprising a particulate filler material, wherein the first layer is disposed on the top surface of the second layer, and Layer 3 is a multilayer film disposed on the bottom surface of the second layer.   The fluoropolymers are each independently polytetrafluoroethylene, polyvinylidene fluoride, polychlorotrifluoroethylene, polyvinyl fluoride, tetrafluoroethylene / hexafluoropropylene / ethylene copolymer, chlorotrifluoroethylene / vinylidene fluoride copolymer, Chlorotrifluoroethylene / hexafluoropropylene, chlorotrifluoroethylene / ethylene copolymer, ethylene / trifluoroethylene copolymer, ethylene / tetrafluoroethylene copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer The multilayer film according to claim 1, which is selected from or a mixture thereof.   The fine particle fillers are independently silica particles, glass beads, glass microspheres, glass fibers, titanium dioxide particles, barium titanate particles, calcium carbonate, zinc oxide, mica, clay, talc, iron oxide, carbon black. Selected from zinc sulfide, barium sulfate, zinc sulfite, cobalt aluminate blue, sodium aluminosulfosilicate, magnesium hydroxide, antimony trioxide, organophosphate compounds, brominated compounds or mixtures thereof. The multilayer film as described.   The fluoropolymers are independently polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer (PFA), ethylene / tetrafluoroethylene copolymer (ETFE), fluorinated ethylene propylene copolymer (FEP). The multilayer film of claim 1, selected from polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE) or mixtures thereof, wherein the particulate filler of the fluoropolymer layer is titanium dioxide.   The multilayer film of claim 1 wherein the breakdown strength (kV) is greater than 3 kV as measured by ASTM method D3755.   The multilayer film of claim 1, wherein the solar reflectance is higher than 70% as measured by ASTM method E424. The multilayer film of claim 1, wherein the moisture permeability is less than about 20 g / m ² / day as measured by ASTM method F1249.   An optoelectronic device comprising an optoelectronic component and the multilayer film of claim 1, wherein the optoelectronic component and the multilayer film are packaged together.   The optoelectronic device according to claim 8, wherein the multilayer film is a backsheet for the optoelectronic component. A first layer comprising a fluoropolymer castable with water or a solvent and a particulate filler material;
A multilayer film comprising a second layer having a top surface and a bottom surface selected from polyimide, polycarbonate, titanium, steel, or aluminum, wherein the first layer is disposed on one side of the second layer. Multi-layer film.   The fluoropolymer is polytetrafluoroethylene, polyvinylidene fluoride, polychlorotrifluoroethylene, polyvinyl fluoride, tetrafluoroethylene / hexafluoropropylene / ethylene copolymer, chlorotrifluoroethylene / vinylidene fluoride copolymer, chlorotrifluoroethylene / From hexafluoropropylene, chlorotrifluoroethylene / ethylene copolymer, ethylene / trifluoroethylene copolymer, ethylene / tetrafluoroethylene copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer or mixtures thereof The multilayer film according to claim 10, which is selected.   The fine particle filler is silica particles, glass beads, glass microspheres, glass fibers, titanium dioxide particles, barium titanate particles, calcium carbonate, zinc oxide, mica, clay, talc, iron oxide, carbon black, zinc sulfide, sulfuric acid. 11. A multilayer film according to claim 10, selected from barium, zinc sulfite, cobalt blue aluminate, sodium aluminosulfosilicate, magnesium hydroxide, antimony trioxide, organophosphate compound, brominated compound or mixtures thereof.   The fluoropolymer may be polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer (PFA), ethylene / tetrafluoroethylene copolymer (ETFE), fluorinated ethylene propylene copolymer (FEP), polyvinylidene fluoride ( The multilayer film of claim 10, wherein the multilayer film is selected from PVDF), polychlorotrifluoroethylene (PCTFE), or mixtures thereof, and the particulate filler of the fluoropolymer layer is titanium dioxide.   The multilayer film of claim 10, wherein the dielectric breakdown strength (kV) is greater than 3 kV as measured by ASTM method D3755.   The multilayer film of claim 10, wherein the solar reflectance is higher than 70% measured by ASTM method E424. The multilayer film of claim 10, wherein the moisture permeability is less than about 20 g / m ² / day as measured by ASTM method F1249.   An optoelectronic device comprising an optoelectronic component and the multilayer film of claim 10, wherein the optoelectronic component and the multilayer film are packaged together.   The optoelectronic device of claim 17, wherein the multilayer film is a backsheet for the optoelectronic component. Applying a casting composition onto a support of polyimide, polycarbonate, titanium, steel, or aluminum, wherein the casting composition comprises:
Career,
A method of preparing a multilayer film comprising a step comprising a fluoropolymer castable with water or a solvent and a particulate filler material.   20. The method of claim 19, further comprising the step of drying the multilayer film.   The fluoropolymer is polytetrafluoroethylene, polyvinylidene fluoride, polychlorotrifluoroethylene, polyvinyl fluoride, tetrafluoroethylene / hexafluoropropylene / ethylene copolymer, chlorotrifluoroethylene / vinylidene fluoride copolymer, chlorotrifluoroethylene / From hexafluoropropylene, chlorotrifluoroethylene / ethylene copolymer, ethylene / trifluoroethylene copolymer, ethylene / tetrafluoroethylene copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer or mixtures thereof 20. The method of claim 19, wherein the method is selected.   The fine particle filler is silica particles, glass beads, glass microspheres, glass fibers, titanium dioxide particles, barium titanate particles, calcium carbonate, zinc oxide, mica, clay, talc, iron oxide, carbon black, zinc sulfide, sulfuric acid. 20. The method of claim 19, wherein the method is selected from barium, zinc sulfite, cobalt blue aluminate, sodium aluminosulfosilicate, magnesium hydroxide, antimony trioxide, an organophosphate compound, a brominated compound, or mixtures thereof.   The fluoropolymer may be polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer (PFA), ethylene / tetrafluoroethylene copolymer (ETFE), fluorinated ethylene propylene copolymer (FEP), polyvinylidene fluoride ( 20. The method of claim 19, wherein the method is selected from PVDF), polychlorotrifluoroethylene (PCTFE), or mixtures thereof, and the particulate filler of the fluoropolymer layer is titanium dioxide.   20. The method of claim 19, wherein the breakdown strength (kV) is greater than 3 kV as measured by ASTM method D3755.   20. The method of claim 19, wherein the solar reflectance is higher than 70% as measured by ASTM method E424. The method of claim 19, wherein the moisture vapor transmission rate is less than about 20 g / m ² / day as measured by ASTM method F1249. Applying a first casting composition to an upper surface of a polyimide, polycarbonate, titanium, steel, or aluminum support, wherein the first casting composition comprises:
Career,
A process comprising a fluoropolymer castable with water or a solvent and a particulate filler material;
Applying a second casting composition to the bottom surface of the polyimide, polycarbonate, titanium, steel, or aluminum support, wherein the second casting composition comprises:
Career,
A process comprising the steps of: containing a fluoropolymer castable with water or a solvent; and a particulate filler material.   28. The method of claim 27, further comprising the step of drying the multilayer film.   The fluoropolymers are each independently polytetrafluoroethylene, polyvinylidene fluoride, polychlorotrifluoroethylene, polyvinyl fluoride, tetrafluoroethylene / hexafluoropropylene / ethylene copolymer, chlorotrifluoroethylene / vinylidene fluoride copolymer, Chlorotrifluoroethylene / hexafluoropropylene, chlorotrifluoroethylene / ethylene copolymer, ethylene / trifluoroethylene copolymer, ethylene / tetrafluoroethylene copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer 28. The method of claim 27, selected from or a mixture thereof.   The fine particle fillers are independently silica particles, glass beads, glass microspheres, glass fibers, titanium dioxide particles, barium titanate particles, calcium carbonate, zinc oxide, mica, clay, talc, iron oxide, carbon black. 28, selected from zinc sulfide, barium sulfate, zinc sulfite, cobalt aluminate blue, sodium aluminosulfosilicate, magnesium hydroxide, antimony trioxide, organophosphate compounds, brominated compounds or mixtures thereof. The method described.   The fluoropolymers are independently polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer (PFA), ethylene / tetrafluoroethylene copolymer (ETFE), fluorinated ethylene propylene copolymer (FEP). 28. The method of claim 27, wherein the particulate filler is selected from, polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE) or mixtures thereof, and the particulate filler of the fluoropolymer layer is titanium dioxide.   28. The method of claim 27, wherein the breakdown strength (kV) is greater than 3 kV as measured by ASTM method D3755.   28. The method of claim 27, wherein the solar reflectance is higher than 70% as measured by ASTM method E424. 28. The method of claim 27, wherein the moisture permeability is less than about 20 g / m < ² > / day as measured by ASTM method F1249.