WO2011109646A1 - Thermally resistant hot melt adhesive composition, methods of using the sam, and solar panel assembly including the same - Google Patents

Thermally resistant hot melt adhesive composition, methods of using the sam, and solar panel assembly including the same Download PDF

Info

Publication number
WO2011109646A1
WO2011109646A1 PCT/US2011/027068 US2011027068W WO2011109646A1 WO 2011109646 A1 WO2011109646 A1 WO 2011109646A1 US 2011027068 W US2011027068 W US 2011027068W WO 2011109646 A1 WO2011109646 A1 WO 2011109646A1
Authority
WO
WIPO (PCT)
Prior art keywords
solar panel
adhesive composition
thermoplastic
component
adhesive
Prior art date
Application number
PCT/US2011/027068
Other languages
French (fr)
Inventor
Heidi Hoglund
Kevin Reid
Sharf U. Ahmed
Original Assignee
H.B. Fuller Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by H.B. Fuller Company filed Critical H.B. Fuller Company
Publication of WO2011109646A1 publication Critical patent/WO2011109646A1/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J177/00—Adhesives based on polyamides obtained by reactions forming a carboxylic amide link in the main chain; Adhesives based on derivatives of such polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/042—PV modules or arrays of single PV cells
    • H01L31/048—Encapsulation of modules
    • H01L31/0481—Encapsulation of modules characterised by the composition of the encapsulation material
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G2170/00—Compositions for adhesives
    • C08G2170/20—Compositions for hot melt adhesives
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/54—Silicon-containing compounds
    • C08K5/544—Silicon-containing compounds containing nitrogen
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/04—Homopolymers or copolymers of ethene
    • C08L23/08—Copolymers of ethene
    • C08L23/0846—Copolymers of ethene with unsaturated hydrocarbons containing other atoms than carbon or hydrogen atoms
    • C08L23/0853—Vinylacetate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2666/00—Composition of polymers characterized by a further compound in the blend, being organic macromolecular compounds, natural resins, waxes or and bituminous materials, non-macromolecular organic substances, inorganic substances or characterized by their function in the composition
    • C08L2666/02—Organic macromolecular compounds, natural resins, waxes or and bituminous materials
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy

Definitions

  • the invention is directed to maintaining adhesion between two substrates under challenging environmental conditions.
  • Solar panels and solar panel fields have unique requirements in that they must maintain their integrity under conditions of high humidity, because they are often positioned out doors and exposed to rain, freezing rain, and snow, and under conditions of widely varying temperature extremes because they are often positioned in hot deserts, on hot asphalt rooftops, and in climates that experience extremely high temperatures, extremely low temperatures, and strong winds.
  • any mechanism used to secure and maintain solar panels in a fixed position must function under a difficult set of environmental conditions.
  • the invention features a hot melt adhesive composition that includes a thermoplastic component having a softening point of at least 120°C and selected from the group consisting of thermoplastic elastomers, thermoplastic polymers, and combinations thereof; a silane adhesion promoter having a flash point greater than 100°C at atmospheric pressure and a boiling point greater than 100°C at from 0.5 mmHg (millimeters of mercury) to 15 mmHg; optionally, a thermoplastic tackifying agent having a softening point greater than 80°C; and optionally a thermoplastic component having a softening point of lower than 120°C and selected from the group consisting of thermoplastic elastomers, thermoplastic polymers, and combinations thereof.
  • the adhesive composition includes from about 5 % by weight to about 35 % by weight of the thermoplastic tackifying agent.
  • the adhesive composition exhibits an initial lap shear of at least 1 psi at 23 °C.
  • the adhesive composition further includes a spacer in a form of spheres, cylinders, tubes, strips, ropes, or any other suitable forms.
  • the invention features a solar panel assembly that includes a solar panel, a support, and a hot melt adhesive composition disclosed herein, the support being bonded to the solar panel through the adhesive composition.
  • the solar panel includes a substrate that includes glass, and a superstrate, the adhesive composition being in contact with the glass of the substrate.
  • the solar panel includes a substrate that includes polymer, and the adhesive composition is in contact with the polymer of the substrate.
  • the support is metal.
  • the support remains bonded to the substrate of the solar panel through the adhesive composition after undergoing the at least one of the Simulated Aging Tests set forth in UL 1703 and the tests set forth in IEC 6646.
  • the invention features a method of adhering a component of a solar panel assembly to a solar panel, the method including contacting at least one of a first component and a second component with an adhesive composition disclosed herein, the first component including a component of the solar panel assembly other than the solar panel, and the second component including the solar panel, and allowing the adhesive composition to bond the first component to the second component.
  • the first component includes at least one of a back rail, a frame and a junction box
  • the second component includes a substrate of the solar panel, the substrate including at least one of polymer and glass.
  • the first component includes a metal back rail and the second component includes a substrate of the solar panel, the substrate including at least one of polymer and glass.
  • the adhesive composition exhibits good green strength, an ability to be handled shortly after application (e.g., an assembly that includes the adhesive composition can be handled shortly after application of the adhesive composition thereto), and, when full adhesion is achieved, good durability in a wide range of environmental conditions.
  • the adhesive composition can also be applied using an automated process.
  • FIG. 1 is a plane view a back rail of a solar panel assembly bonded to a substrate of a solar panel through an adhesive composition disclosed herein.
  • FIG. 2 is a plane view of a junction box of a solar panel assembly bonded to a substrate of a solar panel through an adhesive composition disclosed herein.
  • FIG. 3 is a plane view of an end bracket of a solar panel assembly bonded to a solar panel through an adhesive composition disclosed herein.
  • FIG. 4 is a perspective view of a framed solar panel assembly.
  • FIG. 5 is view taken in cross section along line A-A of the framed solar panel assembly of FIG. 4.
  • FIG. 6 is a perspective view of a solar panel.
  • FIG. 7 is an enlarged view of a portion of a framed solar panel assembly with an adhesive/sealant composition configured according to another embodiment.
  • the hot melt adhesive composition includes a thermoplastic component having a softening point of at least 120°C, and a silane adhesion promoter having a flash point greater than 100°C at atmospheric pressure and a boiling point greater than 100°C at from 0.5 mmHg to 15 mmHg.
  • the adhesive composition exhibits a tensile strength of at least 20 psi at 23 °C, or even at least 70 psi at 23 °C, and at least 20 psi at 85°C, or even at least 70 psi at 85°C.
  • the adhesive composition preferably exhibits an initial lap shear strength (i.e., green strength) of at least 1 psi, at least 2 psi, or even at least 4 psi at 23°C, and a final lap shear of at least 1 psi, at least 2 psi, or even at least 4 psi at 85°C.
  • the adhesive composition also exhibits cold temperature flexibility.
  • the adhesive composition is creep resistant and preferably passes the creep resistance test method at 85°C, or even at a higher temperature than 85°C.
  • Solar panel assemblies that include the adhesive composition preferably pass the Simulated Aging Tests set forth in UL 1703, or even the tests of IEC 6646.
  • the adhesive composition preferably maintains a support bonded to a solar panel after undergoing the Simulated Aging Tests set forth in UL 1703, or even the tests of IEC 6646.
  • the thermoplastic component having a softening point of at least 120°C includes a thermoplastic elastomer that has a softening point of at least 120°C, a thermoplastic polymer that has a softening point of at least 120°C, or a combination thereof.
  • the thermoplastic component having a softening point of at least 320°C is present in the adhesive composition in an amount of from about 10 % by weight, or from about 20% by weight, or from about 40% by weight to about 75 % by weight, or to about 70 % by weight, or to about 60 % by weight, based on the weight of the composition.
  • Suitable thermoplastic elastomers having a softening point of at least 120°C include, e.g., polyetheramide block copolymers, polyesters, butadiene-styrene elastomers including, e.g., A-B, A-B-A, A-(B-A)n-B, (A-B)n-Y, and radial block copolymers and grafted versions thereof where the A block(s) is a polyvinyl aromatic block (e.g., styrene), and the B block is a rubbery midblock (e.g., isoprene, butadiene, ethyl ene-butylene, and ethylene-propylene) (e.g., styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, styrene-ethylene-butylene-
  • thermoplastic elastomers having a softening point of at least 120°C include, e.g., thermoplastic elastomers available under the HYTREL 3078, HYTR.EL 4053 and HYTREL 4056 trade designations from E.I.
  • DuPont de Nemours (Worthington, Delaware), styrene-ethylene/butylene-styrene block copolymers available under the KRATON G series of trade designations including, e.g., KRATON G-1652 and G- 1657, from Kraton Polymers (Houston, Texas); styrene-butadiene-styrene and styrene- isoprene-styrene block copolymers available under the KRATON D series of trade designations including, e.g., KRATON D-l 1 11 and D-l 112 from Kraton Polymers; silane tenninated block copolymers available under the KRATON SKFGI OI trade designation from Kraton Polymers; and styrene-butadiene-styrene and styrene-isoprene-styrene block copolymers available under the VECTOR series of trade designations including,
  • thermoplastic elastomer having a softening point of at least 120°C can be present in the adhesive composition in an amount of 0 % by weight, or from about 10 % by weight, or from about 20% by weight to about 75 % by weight, or to about 60% by weight, or to about 40 % by weight, based on the weight of the composition.
  • thermoplastic polymers having a softening point of at least 120°C can be selected from a variety of classes of thermoplastic polymers including, e.g., polyalkylenes (e.g., polyethylene, polypropylene and polybutylene), poly(alpha)olefms including, e.g., homo-, co- and terpolymers of aliphatic mono- 1 -olefins (alpha olefins) (e.g., poly(aIpha)olefms containing from 2 to 10 carbon atoms), homogeneous linear or substantially linear
  • polyalkylenes e.g., polyethylene, polypropylene and polybutylene
  • poly(alpha)olefms including, e.g., homo-, co- and terpolymers of aliphatic mono- 1 -olefins (alpha olefins) (e.g., poly(aIpha)olefms containing from
  • interpolymers of ethylene having at least one C 3 to C?o alphaolefm polyisobutylenes, poly(alkylene oxides), poly(phenylenediamine terephthalamide), polyesters (e.g.,
  • polyethylene terephthalate polyacrylates, polymethacrylates, polyacrylamides,
  • polyacrylonitriles copolymers of acrylonitrile and monomers including, e.g., butadiene, styrene, polymethyl pentene, and polyphenylene sulfide (e.g., styrene-acrylonitrile, acrylonitrile-butadiene-styrene, acrylonitrile-styrene-butadiene rubbers), polyimides, polyamides, copolymers of vinyl alcohol and ethylenically unsaturated monomers, polyvinyl acetate (e.g..).
  • acrylonitriles copolymers of acrylonitrile and monomers including, e.g., butadiene, styrene, polymethyl pentene, and polyphenylene sulfide (e.g., styrene-acrylonitrile, acrylonitrile-butadiene-styrene, acrylonitrile-styren
  • thermoplastic polymers include asphalts, bitumens, crude rubbers, fluorinated rubbers, and cellulosic resins.
  • thermoplastic polymers having a softening point of at least 120°C include, e.g., amoiphous polyalphaolefins available from Evonik under the trade designations VESTOPLAST 308, VESTOPLAST 608, and VESTOPLAST 703, atactic polypropylene polymers available under the REXTAC series of trade designations including, e.g., REXTAC RT 2535 and RT 2585, from REXtac LLC (Odessa, Texas) and the
  • EASTOFLEX series of trade designations including, e.g., EASTOFLEX El 060, from
  • thermoplastic polymer having a softening point of at least 120°C is preferably present in the adhesive composition in an amount of 0 % by weight, or from about 10 % by weight, or from about 20 % by weight to about 75% by weight, or to about 60 % by weight, or to about 40 % by weight, based on the weight of the composition.
  • the adhesive composition also includes a silane adhesion promoter that has a flash point greater than 100°C at atmospheric pressure and a boiling point greater than 100°C at from 0.5 mmHg to 15 mmHg.
  • Silane adhesion promoters are compounds or monomers that have an average molecular weight of from about 300 to about 1000, or from about 300 to about 800, or from about 500 to about 700.
  • Useful silane adhesion promoters include silyl groups such as alkoxysilyls, acryloxysilyls, alkyloxyiminosilyls, oxime silyls, amino silyls. and combinations thereof.
  • alkoxysilyl groups include methoxysilyl, efhoxysilyl, propoxysilyl, butoxysilyl, and acyloxysilyl reactive groups including, e.g., silyl ester of various acids including, e.g., acetic acid, 2-ethylhexanoic acid, palmitic acid, stearic acid, and oleic acid.
  • Suitable silane adhesion promoters include, e.g., methacryloxy propyl triethoxy-silane, M-aminophenyltriethoxy-silane, P-aminophenyltriethoxy-silane, N-(2-aminoethyl)-3- aminopropyl triethoxy-silane, n-butylaminopropyltrimethoxy-silane,
  • Suitable silane adhesion promoters are commercially available under the SILQUEST
  • the silane adhesion promoter is preferably present in the composition in an amount of from about 0.01 % by weight to about 5 % by weight, from about 0.01 % by weight to about 2
  • the adhesive composition may also include other optional ingredients e.g., a thennoplastic component having a soften point of less than 120°C, a thennoplastic tackifying agent having a ring and ball softening point of at least 80°C. and combinations thereof.
  • a thennoplastic component having a soften point of less than 120°C
  • a thennoplastic tackifying agent having a ring and ball softening point of at least 80°C. and combinations thereof.
  • Useful thermoplastic components having a soften point of less than 120°C include such as thennoplastic elastomers having a soften point of less than 120°C, thennoplastic polymers having a soften point of less than 120°C, and combinations thereof.
  • Examples of useful thennoplastic components include all the classes of the thennoplastic components listed above.
  • thermoplastic elastomers having a soften point of less than 120°C include e.g., polyisobutylene, butyl rubber, ethylene/propylene/diene rubber (i.e., EPDM rubber), and combinations thereof.
  • thermoplastic elastomers having a soften point of less than 120°C include e.g., polyisobutylenes available under the OPPANOL series of trade designations including B50, B80, B100, B 150, B200, B246, B12 and B15 trade designation from BASF (Germany); polyisobutylenes available under the VISTANEX series of trade designations from ExxonMobil including ViSTANEX LMMS, MML-80, MML-100, MML-120, and MML 140; isobutylene-isoprene copolymers available the BUTYL Rubber series of trade designations including BUTYL 268 and BUTYL 065 from ExxonMobil Chemical Co. (Houston, Texas); ethylene-propylene copolymers available under the VISTALON series of trade designations including, e.g., VISTALON 404, from ExxonMobil Chemical Co.
  • thermoplastic polymers having a soften point of less than 120°C include e.g., ethylene vinyl acetate copolymers available under the ATEVA series of trade designations from AT Plastics ( Brampton, Ontario, Canada) including ATEVA 403 OMC and ATEVA 1850, the ELVAX series of trade designations from DuPont de Nemours (Wilmington, Delaware) and the ULTRATHENE series of trade designations from Millennium Petrochemicals (Rolling Meadows, Illinois); ethylene n-butyl acrylate copolymers available under the LOTRYL series of trade designations from Elf Atochem North America (Philadelphia, Pennsylvania), the ESCORENE series of trade designations from ExxonMobil Chemical Co. and the ENATHENE series of trade
  • thermoplastic polyurethane polymers available under the PEARLSTICK series of trade designations from Aries Technologies (Deny, New Hampshire a distributor for Merquinsa, Barcelona, Spain); ethylene acrylate copolymers also available under the ELVALOY series of trade designations from DuPont; and acrylic polymers available under the ELVACITE series of trade designations from 1CI Acrylics (St.
  • useful commercially available homogeneous linear or substantially linear interpolymers of ethylene having at least one C 3 to C 2 o alphaolefm and a polydispersity less than about 2.5 include, e.g., EXACT 5008 ethylene- butene copolymer, EXXPOL SLP-0394 ethylene-propylene copolymer, and EXACT 3031 an ethylene-hexene copolymer from ExxonMobil Chemical Co. (Houston, Texas) and ethylene/1 -octene polymers available under the trade designation AFFINITY from Dow Chemical Co. (Midland, Michigan).
  • thermoplastic component having a softening point of less than 120°C is preferably present in the adhesive composition in an amount of from 0 % by weight, to about 20 % by weight, based on the total weight of the composition.
  • thermoplastic tackifying agents have a ring and ball softening point of at least 80°C, or even from about 85°C to about 150°C.
  • suitable tackifying agents include aliphatic, cycloaliphatic, aromatic, aliphatic-aromatic, aromatic modified alicyclic, and alicyclic hydrocarbon resins and modified versions and hydrogenated derivatives thereof; terpenes (polyterpenes), styrenated terpenes, modified teipenes (e.g., phenolic modified terpen e resins), hydrogenated derivatives thereof, and combinations thereof; alpha methyl styrene resins and hydrogenated derivatives thereof; and combinations thereof.
  • Other useful tackifying agents are disclosed in, e.g., U.S. Patent No. 6,355,317, and incorporated herein.
  • tackifying agents include natural and modified rosins such as gum rosin, wood rosin, tall oil rosin, distilled rosin, completely or partially hydrogenated rosin, dimerized rosin and polymerized rosin; rosin esters including, e.g., glycerol and pentaerythritol esters of natural and modified rosins, (e.g., glycerol esters of pale, wood rosin, glycerol esters of hydrogenated rosin, glycerol esters of polymerized rosin, pentaerythritol esters of
  • Suitable commercially available tackifying agents include, e.g., cycloaliphatic hydrocarbon resins and aromatic-modified, cycloaliphatic hydrocarbon resins available under the ESCOREZ 5637 and ESCOREZ 5340 trade designations from Exxon Mobile Chemical Company; partially hydrogenated cycloaliphatic petroleum hydrocarbon resins available under the EASTOTAC series of trade designations (e.g., EASTOTAC H-l 30 and H-142) from Eastman Chemical Co. (Kingsport, Tennessee) available in grades E, R, L and W, which have differing levels of hydrogenation from least hydrogenated (E) to most hydrogenated (W), the ESCOREZ series of trade designations including, e.g., ESCOREZ 5320 and
  • HERCOLITE 2100 trade designation from Eastman Chemical Co. partially hydro genated aromatic modified petroleum hydrocarbon resins available under the ESCOREZ 5600 trade designation from Exxon Chemical Co.; aromatic hydrogenated hydrocarbon resins available under the trade designation REGALREZ 1 126, and alphamethyl styrene resins available under the trade designation KRISTALEX 5140 from Eastman Chemical Co. (Kingsport, Tennessee).
  • the tackifying agent is preferably present in the composition in an amount of from about 0 % by weight, or from about 5 % by weight to about 15 % by weight, or to about 20 % by weight, or to about 35 % by weight, based on the weight of the composition.
  • the adhesive composition may also include other additives including, e.g., fillers, waxes, plasticizers, thermal stabilizers, light stabilizers (e.g., UV light stabilizers and absorbers), optical brighteners, antistats, lubricants, antioxidants, catalysts, rheology modifiers, biocides, coiTosion inhibitors, dehydrators, organic solvents, colorants (e.g., pigments and dyes), surfactants antiblocking agents, nucleating agents, flame retardants and combinations thereof.
  • additives including, e.g., fillers, waxes, plasticizers, thermal stabilizers, light stabilizers (e.g., UV light stabilizers and absorbers), optical brighteners
  • Suitable fillers include, e.g., fumed silica, precipitated silica, talc, calcium carbonates, carbon black, apatinasilicates, clay, zeolites, ceramics, mica, titanium dioxide, and combinations thereof.
  • the composition can include filler in an amount of from 0 % by weight to about 40 % by weight, from about 10 % by weight to about 35 % by weight, or even from about 20 % by weight to about 30 % by weight, based on the weight of the composition.
  • the plasticizer preferably has a boiling point of greater than about 85°C.
  • Preferred plasticizers include paraffmic oils, naphthenic oils, low molecular weight poly-l-butene, low molecular weight polyisobutene, and combinations thereof.
  • Plasticizer can be present in the composition in an amount of from 0 % by weight to about 10 % by weight, based on the weight of the composition.
  • the adhesive composition is useful for bonding a variety of substrates to each other including substrates made from, e.g., glass, polymer (e.g., polymer composites), metal (e.g., stainless steel, aluminum (e.g., anodized aluminum), galvanized steel and cold-rolled steel), and combinations thereof, treated and coated substrates (e.g., substrates treated for corrosion resistance, aluminum and zinc coated substrates, and combinations thereof), painted substrates and combinations thereof.
  • substrates made from, e.g., glass, polymer (e.g., polymer composites), metal (e.g., stainless steel, aluminum (e.g., anodized aluminum), galvanized steel and cold-rolled steel), and combinations thereof, treated and coated substrates (e.g., substrates treated for corrosion resistance, aluminum and zinc coated substrates, and combinations thereof), painted substrates and combinations thereof.
  • substrates made from, e.g., glass, polymer (e.g., polymer composites), metal (e.g., stainless
  • the adhesive composition is useful for bonding the various components of a solar panel assembly to each other including such components as, e.g., solar panel frames (e.g., C- shaped channels), junction boxes (e.g., polymeric junction boxes), back rails for supporting solar panels (e.g., metal back rails), , brackets (e.g., end brackets), solar panels, components of solar panels (e.g., superstrate, substrate and edges), components used in mounting the solar panels, components used in supporting the solar panels, and combinations thereof.
  • Useful solar panel superstrates include a layer of an ultra violet light transparent material (e.g., glass), and useful solar panel substrates include a layer of polymer, polymer composite, and combinations thereof.
  • the aforesaid adhesive composition is particularly used for sealing and mounting frames on a solar panel to form a framed solar panel assembly.
  • Solar panels are often surrounded by a frame and adhered to the frame with a structural adhesive. It is often necessary to include both a structural adhesive and a moisture vapor barrier to achieve a framed solar panel that will maintain its integrity under the rigorous conditions to which it is often exposed including, e.g., high humidity, widely varying temperature extremes, and strong winds.
  • the aforesaid adhesive composition can function as both an adhesive and a moisture vapor barrier, therefore, is referred to as an adhesive/sealant composition.
  • the adhesive/sealant composition exhibits a moisture vapor transmission rate (MVTR) of no greater than 2 g/m /day.
  • the adhesive/sealant composition exhibits a MVTR of no greater than 1 g/m 2 /day.
  • the adhesive/sealant composition exhibits a MVTR of no greater than 0.2 g/m 2 /day.
  • the invention provides a framed solar panel assembly.
  • the solar panel assembly includes a solar panel that includes edges; a peripheral frame including an interior surface; and any one of the aforesaid adhesive/sealant compositions disposed between the interior surface of the frame and the edges of the solar panel, the panel being bonded to the frame through the adhesive/sealant composition.
  • the invention provides a method of framing a solar panel.
  • the method includes contacting at least one of the interior surfaces of a frame and the solar panel with any one of the adhesive/sealant compositions disclosed herein, and affixing the frame to the solar panel.
  • the framed solar panel assemblies exhibit good protection against moisture, which can adversely affect the efficiency of the solar panel.
  • the method provides an efficient framing process and enables the manufacture of a framed solar panel assembly using an adhesive/sealant composition that functions as both an adhesive composition and a sealant composition at the same time, especially as an edge sealant composition.
  • a back rail 10 of a solar panel assembly 5 is bonded to a substrate 8 of a solar panel 12 through an adhesive composition 6.
  • FIG. 2 illustrates a junction box 20 bonded to a substrate 8 of a solar panel 12 through an adhesive composition 6.
  • an end bracket 30 is bonded to an edge 22, substrate 8 and superstate 24 of a solar panel 12 through an adhesive composition 6.
  • FIGS. 4-6 illustrate a framed solar panel assembly 1 1 includes a solar panel 12 and a peripheral frame 14.
  • the solar panel 12 is surrounded by the frame 14 along edges 16, 18, 20, and 22.
  • An adhesive/sealant composition 4 is disposed between the edges 16, 18, 20 and 22 and the interior surface 28 of the frame 14 so as to seal the solar panel 12, which provides a barrier to moisture entering the solar panel 12, and to adhere the frame 14 to the edges 16, 18, 20 and 22 of the solar panel 12.
  • a continuous bead of the adhesive/sealant composition 4 is in continuous contact with the edge of the solar panel 12 to form a vapor barrier.
  • the frame 14 defines a U-shaped channel 32 that receives an edge of the solar panel 12.
  • the channel 32 includes a back wall 34.
  • the adhesive/sealant composition 4 is in contact with at least one component of the channel 32 of the frame 14, e.g., the back wall 34, a top wall 36, and a bottom wall 38 of the frame 14, and at least one component of the solar panel 12, e.g., the edges 16, 18, 20, and 22 of the panel 12, the superstrate 24 (e.g., a glass superstrate) of the solar panel 12, and the substrate 8 (e.g., a polymer substrate or a glass substrate) of the solar panel 12, as shown in FIG. 6.
  • the substrate 8 e.g., a polymer substrate or a glass substrate
  • the adhesive/sealant composition 4 is positioned in a discontinuous manner on the bottom wall 38, back wall 34, and top wall 36 of the channel 32 of the frame 14 that receives the solar panel 12.
  • the adhesive/sealant composition 4 bonds the frame 14 to the solar panel 12 and preferably provides a vapor barrier.
  • the adhesive/sealant composition 4 preferably exhibits a moisture vapor transmission rate (MVTR) of no greater than 2 g/m 2 /day, when in the form of a 60 mil film.
  • MVTR moisture vapor transmission rate
  • solar panel assemblies in which the adhesive composition is particularly useful include those constructions described in, e.g., U.S. 2009/0205703 and U.S. 2010/0018570, which are incorporated herein.
  • Test procedures used in the examples include the following.
  • the tensile strength at break is determined according to ASTM-D638-00 entitled, "Standard Test Method for Tensile Properties of Plastics. " A homogeneous film of the adhesive composition is pressed to a thickness of from 40 mil to 60 mil. The film is conditioned at 23°C and 50 % relative humidity for at least about 24 hours. Specimens are cut from the film and tested for tensile strength at break according to ASTM D638-00. Lap Shear Strength Test Method
  • the lap shear strength is determined according to ASTM C-961-01 entitled. "Standard Test Method for Lap Shear Strength of Hot Applied Sealants, " with the exception that the test specimen is prepared as follows. A 1 in x 1 in film of adhesive composition having a thickness of from 50 mil to 60 mil is placed on a 4 in x 1 in piece of a first substrate (stainless steel). Another 1 in x 4 in piece of a second substrate (stainless steel) is then placed on top of the film and pressed hard against the film using maximum hand pressure. The test specimen is then heated to a temperature of from 120°C-150°C for 10 minutes to achieve good wet out of the adhesive composition.
  • Initial lap shear i.e., green strength
  • Final lap shear is measured at least about 24 hours after preparing the bond sample.
  • Creep resistance is determined as follows. A 1 in x 1 in film of an adhesive composition having a thickness of from 50 mil to 60 mil is placed on a 4 in x 1 in piece of aluminum. A 1 in x 3 in piece of glass is then placed on top of the film and pressed hard against the film using maximum hand pressure. The test specimen is then heated to a temperature of from 120°C to 150°C for 10 minutes to achieve good wet out of the adhesive composition. The test specimen is conditioned at 23°C and 50% relative humidity for at least about 24 hours.
  • a one pound load is then hung from an end of the test specimen and placed in an oven at a specified temperature, e.g., at 85°C or even a higher temperature. The time to failure is recorded. The test specimen is recorded as pass at the test temperature if there is no failure after seven days.
  • Hot melt adhesive compositions of Examples 1 and 2 are prepared by mixing all the ingredients according to Table I at 150°C until uniformly blended.
  • the adhesive is prepared by mixing all the ingredients according to Table I at 150°C until uniformly blended.
  • compositions are then tested according to the test methods disclosed herein, and the results are also listed in Table I.

Abstract

A hot melt adhesive composition and use thereof for solar panel assembly. The adhesive composition includes a thermoplastic component having a softening point of at least 1200C and selected from the group consisting of thermoplastic elastomers, thermoplastic polymers and combinations thereof; a silane adhesion promoter having a flash point greater than 1000C at atmospheric pressure and a boiling point greater than 1000C at from 0.5 mmHg to 15 mmHg; and optionally, a thermoplastic tackifying agent having a softening point greater than 800C.

Description

THERMALLY RESISTANT HOT MELT ADHESIVE COMPOSITION, METHODS OF USING THE SAME, AND SOLAR PANEL ASSEMBLY INCLUDING THE SAME
This application claims priority to U.S. Serial No. 61 /310,904 filed March, 5, 2010, and U.S. Serial No. 61/310,928, filed March 5, 2010 and U.S. Serial No. 61/310,834, filed March 5, 2010, which are incorporated herein.
BACKGROUND OF THE INVENTION
The invention is directed to maintaining adhesion between two substrates under challenging environmental conditions.
Solar panels and solar panel fields have unique requirements in that they must maintain their integrity under conditions of high humidity, because they are often positioned out doors and exposed to rain, freezing rain, and snow, and under conditions of widely varying temperature extremes because they are often positioned in hot deserts, on hot asphalt rooftops, and in climates that experience extremely high temperatures, extremely low temperatures, and strong winds. Thus, any mechanism used to secure and maintain solar panels in a fixed position must function under a difficult set of environmental conditions.
SUMMARY OF THE INVENTION
In one aspect, the invention features a hot melt adhesive composition that includes a thermoplastic component having a softening point of at least 120°C and selected from the group consisting of thermoplastic elastomers, thermoplastic polymers, and combinations thereof; a silane adhesion promoter having a flash point greater than 100°C at atmospheric pressure and a boiling point greater than 100°C at from 0.5 mmHg (millimeters of mercury) to 15 mmHg; optionally, a thermoplastic tackifying agent having a softening point greater than 80°C; and optionally a thermoplastic component having a softening point of lower than 120°C and selected from the group consisting of thermoplastic elastomers, thermoplastic polymers, and combinations thereof. In one embodiment, the adhesive composition includes from about 5 % by weight to about 35 % by weight of the thermoplastic tackifying agent.
In one embodiment, the adhesive composition exhibits an initial lap shear of at least 1 psi at 23 °C.
In one embodiment, the adhesive composition further includes a spacer in a form of spheres, cylinders, tubes, strips, ropes, or any other suitable forms.
In another aspect, the invention features a solar panel assembly that includes a solar panel, a support, and a hot melt adhesive composition disclosed herein, the support being bonded to the solar panel through the adhesive composition. In some embodiments, the solar panel includes a substrate that includes glass, and a superstrate, the adhesive composition being in contact with the glass of the substrate. In one embodiment, the solar panel includes a substrate that includes polymer, and the adhesive composition is in contact with the polymer of the substrate. In another embodiment, the support is metal.
In other embodiments, the support remains bonded to the substrate of the solar panel through the adhesive composition after undergoing the at least one of the Simulated Aging Tests set forth in UL 1703 and the tests set forth in IEC 6646.
In other aspects, the invention features a method of adhering a component of a solar panel assembly to a solar panel, the method including contacting at least one of a first component and a second component with an adhesive composition disclosed herein, the first component including a component of the solar panel assembly other than the solar panel, and the second component including the solar panel, and allowing the adhesive composition to bond the first component to the second component. In one embodiment, the first component includes at least one of a back rail, a frame and a junction box, and the second component includes a substrate of the solar panel, the substrate including at least one of polymer and glass. In other embodiments, the first component includes a metal back rail and the second component includes a substrate of the solar panel, the substrate including at least one of polymer and glass.
The adhesive composition exhibits good green strength, an ability to be handled shortly after application (e.g., an assembly that includes the adhesive composition can be handled shortly after application of the adhesive composition thereto), and, when full adhesion is achieved, good durability in a wide range of environmental conditions. The adhesive composition can also be applied using an automated process.
Other features and advantages will be apparent from the following description of the preferred embodiments, the drawings, and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plane view a back rail of a solar panel assembly bonded to a substrate of a solar panel through an adhesive composition disclosed herein.
FIG. 2 is a plane view of a junction box of a solar panel assembly bonded to a substrate of a solar panel through an adhesive composition disclosed herein.
FIG. 3 is a plane view of an end bracket of a solar panel assembly bonded to a solar panel through an adhesive composition disclosed herein.
FIG. 4 is a perspective view of a framed solar panel assembly.
FIG. 5 is view taken in cross section along line A-A of the framed solar panel assembly of FIG. 4.
FIG. 6 is a perspective view of a solar panel.
FIG. 7 is an enlarged view of a portion of a framed solar panel assembly with an adhesive/sealant composition configured according to another embodiment.
DETAILED DESCRIPTION OF THE INVENTION
In one embodiment, the hot melt adhesive composition includes a thermoplastic component having a softening point of at least 120°C, and a silane adhesion promoter having a flash point greater than 100°C at atmospheric pressure and a boiling point greater than 100°C at from 0.5 mmHg to 15 mmHg. The adhesive composition exhibits a tensile strength of at least 20 psi at 23 °C, or even at least 70 psi at 23 °C, and at least 20 psi at 85°C, or even at least 70 psi at 85°C.
The adhesive composition preferably exhibits an initial lap shear strength (i.e., green strength) of at least 1 psi, at least 2 psi, or even at least 4 psi at 23°C, and a final lap shear of at least 1 psi, at least 2 psi, or even at least 4 psi at 85°C. Preferably the adhesive composition also exhibits cold temperature flexibility.
The adhesive composition is creep resistant and preferably passes the creep resistance test method at 85°C, or even at a higher temperature than 85°C.
Solar panel assemblies that include the adhesive composition preferably pass the Simulated Aging Tests set forth in UL 1703, or even the tests of IEC 6646. The adhesive composition preferably maintains a support bonded to a solar panel after undergoing the Simulated Aging Tests set forth in UL 1703, or even the tests of IEC 6646. THERMOPLASTIC COMPONENT HAVING A SOFTING POINT OF AT LEAST 120°C The thermoplastic component having a softening point of at least 120°C includes a thermoplastic elastomer that has a softening point of at least 120°C, a thermoplastic polymer that has a softening point of at least 120°C, or a combination thereof.
In some embodiments, the thermoplastic component having a softening point of at least 320°C is present in the adhesive composition in an amount of from about 10 % by weight, or from about 20% by weight, or from about 40% by weight to about 75 % by weight, or to about 70 % by weight, or to about 60 % by weight, based on the weight of the composition.
Suitable thermoplastic elastomers having a softening point of at least 120°C include, e.g., polyetheramide block copolymers, polyesters, butadiene-styrene elastomers including, e.g., A-B, A-B-A, A-(B-A)n-B, (A-B)n-Y, and radial block copolymers and grafted versions thereof where the A block(s) is a polyvinyl aromatic block (e.g., styrene), and the B block is a rubbery midblock (e.g., isoprene, butadiene, ethyl ene-butylene, and ethylene-propylene) (e.g., styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, styrene-ethylene-butylene-styrene block copolymers, styrene-efhylene-propylene-styrene block copolymers), polyurethane elastomers, polyolefin elastomers, elastomeric ethylene vinyl acetate, ethylene-octene block copolymers, and mixtures thereof.
Useful commercially available thermoplastic elastomers having a softening point of at least 120°C include, e.g., thermoplastic elastomers available under the HYTREL 3078, HYTR.EL 4053 and HYTREL 4056 trade designations from E.I. DuPont de Nemours (Worthington, Delaware), styrene-ethylene/butylene-styrene block copolymers available under the KRATON G series of trade designations including, e.g., KRATON G-1652 and G- 1657, from Kraton Polymers (Houston, Texas); styrene-butadiene-styrene and styrene- isoprene-styrene block copolymers available under the KRATON D series of trade designations including, e.g., KRATON D-l 1 11 and D-l 112 from Kraton Polymers; silane tenninated block copolymers available under the KRATON SKFGI OI trade designation from Kraton Polymers; and styrene-butadiene-styrene and styrene-isoprene-styrene block copolymers available under the VECTOR series of trade designations including, e.g., VECTOR 41 12, 41 14 and 441 1 from Dexco Polymers (Houston, Texas); ethylene-octene block copolymers available under the INSITE trade designation including e.g., INSITE 9807- 15 from Dow Chemical Company.
The thermoplastic elastomer having a softening point of at least 120°C can be present in the adhesive composition in an amount of 0 % by weight, or from about 10 % by weight, or from about 20% by weight to about 75 % by weight, or to about 60% by weight, or to about 40 % by weight, based on the weight of the composition.
The thermoplastic polymers having a softening point of at least 120°C can be selected from a variety of classes of thermoplastic polymers including, e.g., polyalkylenes (e.g., polyethylene, polypropylene and polybutylene), poly(alpha)olefms including, e.g., homo-, co- and terpolymers of aliphatic mono- 1 -olefins (alpha olefins) (e.g., poly(aIpha)olefms containing from 2 to 10 carbon atoms), homogeneous linear or substantially linear
interpolymers of ethylene having at least one C3 to C?o alphaolefm, polyisobutylenes, poly(alkylene oxides), poly(phenylenediamine terephthalamide), polyesters (e.g.,
polyethylene terephthalate), polyacrylates, polymethacrylates, polyacrylamides,
polyacrylonitriles, copolymers of acrylonitrile and monomers including, e.g., butadiene, styrene, polymethyl pentene, and polyphenylene sulfide (e.g., styrene-acrylonitrile, acrylonitrile-butadiene-styrene, acrylonitrile-styrene-butadiene rubbers), polyimides, polyamides, copolymers of vinyl alcohol and ethylenically unsaturated monomers, polyvinyl acetate (e.g.. ethylene vinyl acetate), polyvinyl alcohol, vinyl chloride homopolymers and copolymers (e.g., polyvinyl chloride), terpolymers of ethylene, carbon monoxide and acrylic acid ester or vinyl monomer, polysiloxanes, polyurethanes, polystyrene, and combinations thereof, and homopolyiners, copolymers and terpolymers thereof, and mixtures thereof. Other useful classes of thermoplastic polymers include asphalts, bitumens, crude rubbers, fluorinated rubbers, and cellulosic resins.
Useful commercially available thermoplastic polymers having a softening point of at least 120°C include, e.g., amoiphous polyalphaolefins available from Evonik under the trade designations VESTOPLAST 308, VESTOPLAST 608, and VESTOPLAST 703, atactic polypropylene polymers available under the REXTAC series of trade designations including, e.g., REXTAC RT 2535 and RT 2585, from REXtac LLC (Odessa, Texas) and the
EASTOFLEX series of trade designations including, e.g., EASTOFLEX El 060, from
Eastman Chemical Co. (Kingsport, Tennessee); polyethylene polymers available under the EPOLENE C-17 trade designation from Westlake Chemical Corporation; ethylene methyl acrylate copolymers available under the OPTEMA series of trade designations from
ExxonMobil Chemical Co. (Houston, Texas); and butylene/poly(alkylene ether) phthalate polymers available under the HYTREL trade designations from DuPont.
The thermoplastic polymer having a softening point of at least 120°C is preferably present in the adhesive composition in an amount of 0 % by weight, or from about 10 % by weight, or from about 20 % by weight to about 75% by weight, or to about 60 % by weight, or to about 40 % by weight, based on the weight of the composition.
SILANE ADHESION PROMOTER
The adhesive composition also includes a silane adhesion promoter that has a flash point greater than 100°C at atmospheric pressure and a boiling point greater than 100°C at from 0.5 mmHg to 15 mmHg. Silane adhesion promoters are compounds or monomers that have an average molecular weight of from about 300 to about 1000, or from about 300 to about 800, or from about 500 to about 700. Useful silane adhesion promoters include silyl groups such as alkoxysilyls, acryloxysilyls, alkyloxyiminosilyls, oxime silyls, amino silyls. and combinations thereof. Examples of useful alkoxysilyl groups include methoxysilyl, efhoxysilyl, propoxysilyl, butoxysilyl, and acyloxysilyl reactive groups including, e.g., silyl ester of various acids including, e.g., acetic acid, 2-ethylhexanoic acid, palmitic acid, stearic acid, and oleic acid.
Suitable silane adhesion promoters include, e.g., methacryloxy propyl triethoxy-silane, M-aminophenyltriethoxy-silane, P-aminophenyltriethoxy-silane, N-(2-aminoethyl)-3- aminopropyl triethoxy-silane, n-butylaminopropyltrimethoxy-silane,
bis(triethoylsilylpropyl)amine, bis(trimethoylsilylpropyl) amine, 3-(trimethoxylsilyl) propyl succinic anhydride, (3-glycidoxypropyl) mefhyldiethoxy-silane. (3-glycidoxypropyl) methyldimethoxy-silane, tris(3-trimethoxysilyIpropyl) isocyanurate, bis(triethoxysilyl)ethane, bis(trimethoxysilyl) benzene, and combinations thereof.
Suitable silane adhesion promoters are commercially available under the SILQUEST
Α- 1170 and SILQUEST SILQUEST A- LINK 597 trade designations from Momentive
Performance Materials, Inc. (Albany, New York).
The silane adhesion promoter is preferably present in the composition in an amount of from about 0.01 % by weight to about 5 % by weight, from about 0.01 % by weight to about 2
% by weight, or even from about 0.01 % by weight to about 1 % by weight, based on the weight of the composition.
OTHER INGREDIENTS/ADDITIVES
The adhesive composition may also include other optional ingredients e.g., a thennoplastic component having a soften point of less than 120°C, a thennoplastic tackifying agent having a ring and ball softening point of at least 80°C. and combinations thereof.
Useful thermoplastic components having a soften point of less than 120°C include such as thennoplastic elastomers having a soften point of less than 120°C, thennoplastic polymers having a soften point of less than 120°C, and combinations thereof. Examples of useful thennoplastic components include all the classes of the thennoplastic components listed above.
Examples of useful thermoplastic elastomers having a soften point of less than 120°C include e.g., polyisobutylene, butyl rubber, ethylene/propylene/diene rubber (i.e., EPDM rubber), and combinations thereof. Commercially available examples of useful thermoplastic elastomers having a soften point of less than 120°C include e.g., polyisobutylenes available under the OPPANOL series of trade designations including B50, B80, B100, B 150, B200, B246, B12 and B15 trade designation from BASF (Germany); polyisobutylenes available under the VISTANEX series of trade designations from ExxonMobil including ViSTANEX LMMS, MML-80, MML-100, MML-120, and MML 140; isobutylene-isoprene copolymers available the BUTYL Rubber series of trade designations including BUTYL 268 and BUTYL 065 from ExxonMobil Chemical Co. (Houston, Texas); ethylene-propylene copolymers available under the VISTALON series of trade designations including, e.g., VISTALON 404, from ExxonMobil Chemical Co.
Commercially available examples of useful thermoplastic polymers having a soften point of less than 120°C include e.g., ethylene vinyl acetate copolymers available under the ATEVA series of trade designations from AT Plastics ( Brampton, Ontario, Canada) including ATEVA 403 OMC and ATEVA 1850, the ELVAX series of trade designations from DuPont de Nemours (Wilmington, Delaware) and the ULTRATHENE series of trade designations from Millennium Petrochemicals (Rolling Meadows, Illinois); ethylene n-butyl acrylate copolymers available under the LOTRYL series of trade designations from Elf Atochem North America (Philadelphia, Pennsylvania), the ESCORENE series of trade designations from ExxonMobil Chemical Co. and the ENATHENE series of trade
designations from Millennium Petrochemicals; ethylene n-butyl acrylate carbon monoxide terpolymers available under the ELVALOY series of trade designations from DuPont;
thermoplastic polyurethane polymers available under the PEARLSTICK series of trade designations from Aries Technologies (Deny, New Hampshire a distributor for Merquinsa, Barcelona, Spain); ethylene acrylate copolymers also available under the ELVALOY series of trade designations from DuPont; and acrylic polymers available under the ELVACITE series of trade designations from 1CI Acrylics (St. Louis, Missouri); useful commercially available homogeneous linear or substantially linear interpolymers of ethylene having at least one C3 to C2o alphaolefm and a polydispersity less than about 2.5 include, e.g., EXACT 5008 ethylene- butene copolymer, EXXPOL SLP-0394 ethylene-propylene copolymer, and EXACT 3031 an ethylene-hexene copolymer from ExxonMobil Chemical Co. (Houston, Texas) and ethylene/1 -octene polymers available under the trade designation AFFINITY from Dow Chemical Co. (Midland, Michigan).
The thermoplastic component having a softening point of less than 120°C is preferably present in the adhesive composition in an amount of from 0 % by weight, to about 20 % by weight, based on the total weight of the composition.
Preferred thermoplastic tackifying agents have a ring and ball softening point of at least 80°C, or even from about 85°C to about 150°C. Examples of suitable tackifying agents include aliphatic, cycloaliphatic, aromatic, aliphatic-aromatic, aromatic modified alicyclic, and alicyclic hydrocarbon resins and modified versions and hydrogenated derivatives thereof; terpenes (polyterpenes), styrenated terpenes, modified teipenes (e.g., phenolic modified terpen e resins), hydrogenated derivatives thereof, and combinations thereof; alpha methyl styrene resins and hydrogenated derivatives thereof; and combinations thereof. Other useful tackifying agents are disclosed in, e.g., U.S. Patent No. 6,355,317, and incorporated herein.
Other tackifying agents include natural and modified rosins such as gum rosin, wood rosin, tall oil rosin, distilled rosin, completely or partially hydrogenated rosin, dimerized rosin and polymerized rosin; rosin esters including, e.g., glycerol and pentaerythritol esters of natural and modified rosins, (e.g., glycerol esters of pale, wood rosin, glycerol esters of hydrogenated rosin, glycerol esters of polymerized rosin, pentaerythritol esters of
hydrogenated rosin and phenolic-modified pentaerythritol esters of rosin); alpha methyl styrene resins and hydrogenated derivatives thereof; low molecular weight polylactic acid; and combinations thereof.
Suitable commercially available tackifying agents include, e.g., cycloaliphatic hydrocarbon resins and aromatic-modified, cycloaliphatic hydrocarbon resins available under the ESCOREZ 5637 and ESCOREZ 5340 trade designations from Exxon Mobile Chemical Company; partially hydrogenated cycloaliphatic petroleum hydrocarbon resins available under the EASTOTAC series of trade designations (e.g., EASTOTAC H-l 30 and H-142) from Eastman Chemical Co. (Kingsport, Tennessee) available in grades E, R, L and W, which have differing levels of hydrogenation from least hydrogenated (E) to most hydrogenated (W), the ESCOREZ series of trade designations including, e.g., ESCOREZ 5320 and
ESCOREZ 5400, from ExxonMobil Chemical Co. (Houston, Texas), and under the
HERCOLITE 2100 trade designation from Eastman Chemical Co.; partially hydro genated aromatic modified petroleum hydrocarbon resins available under the ESCOREZ 5600 trade designation from Exxon Chemical Co.; aromatic hydrogenated hydrocarbon resins available under the trade designation REGALREZ 1 126, and alphamethyl styrene resins available under the trade designation KRISTALEX 5140 from Eastman Chemical Co. (Kingsport, Tennessee).
The tackifying agent is preferably present in the composition in an amount of from about 0 % by weight, or from about 5 % by weight to about 15 % by weight, or to about 20 % by weight, or to about 35 % by weight, based on the weight of the composition.The adhesive composition may also include other additives including, e.g., fillers, waxes, plasticizers, thermal stabilizers, light stabilizers (e.g., UV light stabilizers and absorbers), optical brighteners, antistats, lubricants, antioxidants, catalysts, rheology modifiers, biocides, coiTosion inhibitors, dehydrators, organic solvents, colorants (e.g., pigments and dyes), surfactants antiblocking agents, nucleating agents, flame retardants and combinations thereof.
Suitable fillers include, e.g., fumed silica, precipitated silica, talc, calcium carbonates, carbon black, aluniinasilicates, clay, zeolites, ceramics, mica, titanium dioxide, and combinations thereof. The composition can include filler in an amount of from 0 % by weight to about 40 % by weight, from about 10 % by weight to about 35 % by weight, or even from about 20 % by weight to about 30 % by weight, based on the weight of the composition.
The plasticizer preferably has a boiling point of greater than about 85°C. Preferred plasticizers include paraffmic oils, naphthenic oils, low molecular weight poly-l-butene, low molecular weight polyisobutene, and combinations thereof. Plasticizer can be present in the composition in an amount of from 0 % by weight to about 10 % by weight, based on the weight of the composition.
The adhesive composition is useful for bonding a variety of substrates to each other including substrates made from, e.g., glass, polymer (e.g., polymer composites), metal (e.g., stainless steel, aluminum (e.g., anodized aluminum), galvanized steel and cold-rolled steel), and combinations thereof, treated and coated substrates (e.g., substrates treated for corrosion resistance, aluminum and zinc coated substrates, and combinations thereof), painted substrates and combinations thereof.
The adhesive composition is useful for bonding the various components of a solar panel assembly to each other including such components as, e.g., solar panel frames (e.g., C- shaped channels), junction boxes (e.g., polymeric junction boxes), back rails for supporting solar panels (e.g., metal back rails), , brackets (e.g., end brackets), solar panels, components of solar panels (e.g., superstrate, substrate and edges), components used in mounting the solar panels, components used in supporting the solar panels, and combinations thereof. Useful solar panel superstrates include a layer of an ultra violet light transparent material (e.g., glass), and useful solar panel substrates include a layer of polymer, polymer composite, and combinations thereof.
In one embodiment, the aforesaid adhesive composition is particularly used for sealing and mounting frames on a solar panel to form a framed solar panel assembly.
Solar panels are often surrounded by a frame and adhered to the frame with a structural adhesive. It is often necessary to include both a structural adhesive and a moisture vapor barrier to achieve a framed solar panel that will maintain its integrity under the rigorous conditions to which it is often exposed including, e.g., high humidity, widely varying temperature extremes, and strong winds.
In the embodiments where it is used for framing solar panels, the aforesaid adhesive composition can function as both an adhesive and a moisture vapor barrier, therefore, is referred to as an adhesive/sealant composition. In some embodiments, the adhesive/sealant composition exhibits a moisture vapor transmission rate (MVTR) of no greater than 2 g/m /day. In some embodiments, the adhesive/sealant composition exhibits a MVTR of no greater than 1 g/m2/day. In some embodiments, the adhesive/sealant composition exhibits a MVTR of no greater than 0.2 g/m2/day. In one embodiment, the invention provides a framed solar panel assembly. The solar panel assembly includes a solar panel that includes edges; a peripheral frame including an interior surface; and any one of the aforesaid adhesive/sealant compositions disposed between the interior surface of the frame and the edges of the solar panel, the panel being bonded to the frame through the adhesive/sealant composition.
In another embodiment, the invention provides a method of framing a solar panel. The method includes contacting at least one of the interior surfaces of a frame and the solar panel with any one of the adhesive/sealant compositions disclosed herein, and affixing the frame to the solar panel.
The framed solar panel assemblies exhibit good protection against moisture, which can adversely affect the efficiency of the solar panel. The method provides an efficient framing process and enables the manufacture of a framed solar panel assembly using an adhesive/sealant composition that functions as both an adhesive composition and a sealant composition at the same time, especially as an edge sealant composition.
Other features and advantages of the invention will be apparent from the following description of the preferred embodiments, the drawings, and from the claims.
Turning to FIG, 1 , a back rail 10 of a solar panel assembly 5 is bonded to a substrate 8 of a solar panel 12 through an adhesive composition 6.
FIG. 2 illustrates a junction box 20 bonded to a substrate 8 of a solar panel 12 through an adhesive composition 6.
Referring to FIG. 3, an end bracket 30 is bonded to an edge 22, substrate 8 and superstate 24 of a solar panel 12 through an adhesive composition 6.
FIGS. 4-6 illustrate a framed solar panel assembly 1 1 includes a solar panel 12 and a peripheral frame 14. The solar panel 12 is surrounded by the frame 14 along edges 16, 18, 20, and 22. An adhesive/sealant composition 4 is disposed between the edges 16, 18, 20 and 22 and the interior surface 28 of the frame 14 so as to seal the solar panel 12, which provides a barrier to moisture entering the solar panel 12, and to adhere the frame 14 to the edges 16, 18, 20 and 22 of the solar panel 12. A continuous bead of the adhesive/sealant composition 4 is in continuous contact with the edge of the solar panel 12 to form a vapor barrier. The frame 14 defines a U-shaped channel 32 that receives an edge of the solar panel 12. The channel 32 includes a back wall 34. a top wall 36, and a bottom wall 38. The adhesive/sealant composition 4 is in contact with at least one component of the channel 32 of the frame 14, e.g., the back wall 34, a top wall 36, and a bottom wall 38 of the frame 14, and at least one component of the solar panel 12, e.g., the edges 16, 18, 20, and 22 of the panel 12, the superstrate 24 (e.g., a glass superstrate) of the solar panel 12, and the substrate 8 (e.g., a polymer substrate or a glass substrate) of the solar panel 12, as shown in FIG. 6.
Turning to FIG. 7, the adhesive/sealant composition 4 is positioned in a discontinuous manner on the bottom wall 38, back wall 34, and top wall 36 of the channel 32 of the frame 14 that receives the solar panel 12. The adhesive/sealant composition 4 bonds the frame 14 to the solar panel 12 and preferably provides a vapor barrier. The adhesive/sealant composition 4 preferably exhibits a moisture vapor transmission rate (MVTR) of no greater than 2 g/m2/day, when in the form of a 60 mil film.
Other solar panel assemblies in which the adhesive composition is particularly useful include those constructions described in, e.g., U.S. 2009/0205703 and U.S. 2010/0018570, which are incorporated herein.
The invention will now be described by way of the following examples. All parts, ratios, percents and amounts stated in the Examples are by weight unless otherwise specified
EXAMPLES
Test Procedures
Test procedures used in the examples include the following.
Tensile Strength Test Method
The tensile strength at break is determined according to ASTM-D638-00 entitled, "Standard Test Method for Tensile Properties of Plastics." A homogeneous film of the adhesive composition is pressed to a thickness of from 40 mil to 60 mil. The film is conditioned at 23°C and 50 % relative humidity for at least about 24 hours. Specimens are cut from the film and tested for tensile strength at break according to ASTM D638-00. Lap Shear Strength Test Method
The lap shear strength is determined according to ASTM C-961-01 entitled. "Standard Test Method for Lap Shear Strength of Hot Applied Sealants," with the exception that the test specimen is prepared as follows. A 1 in x 1 in film of adhesive composition having a thickness of from 50 mil to 60 mil is placed on a 4 in x 1 in piece of a first substrate (stainless steel). Another 1 in x 4 in piece of a second substrate (stainless steel) is then placed on top of the film and pressed hard against the film using maximum hand pressure. The test specimen is then heated to a temperature of from 120°C-150°C for 10 minutes to achieve good wet out of the adhesive composition.
Initial lap shear (i.e., green strength) is measured within about one to two hours after preparing the bond sample.
Final lap shear is measured at least about 24 hours after preparing the bond sample.
Creep Resistance Test Method
Creep resistance is determined as follows. A 1 in x 1 in film of an adhesive composition having a thickness of from 50 mil to 60 mil is placed on a 4 in x 1 in piece of aluminum. A 1 in x 3 in piece of glass is then placed on top of the film and pressed hard against the film using maximum hand pressure. The test specimen is then heated to a temperature of from 120°C to 150°C for 10 minutes to achieve good wet out of the adhesive composition. The test specimen is conditioned at 23°C and 50% relative humidity for at least about 24 hours.
A one pound load is then hung from an end of the test specimen and placed in an oven at a specified temperature, e.g., at 85°C or even a higher temperature. The time to failure is recorded. The test specimen is recorded as pass at the test temperature if there is no failure after seven days. Cold Temperature Flexibility Test Method
Flexibility is measured according to ASTM D31 1 1 entitled, "Flexibility Determination of Hot Melt Adhesive by Mandrel Bend Test Method" (which is incorporated herein) using a free film. The results are reported as pass or fail according to the criteria set forth in ASTM D31 1 1.
Examples 1 and 2
Hot melt adhesive compositions of Examples 1 and 2 are prepared by mixing all the ingredients according to Table I at 150°C until uniformly blended. The adhesive
compositions are then tested according to the test methods disclosed herein, and the results are also listed in Table I.
Figure imgf000016_0001
The relevant portions of all documents disclosed herein are hereby incoiporated by reference in their entirety.
Other embodiments are within the claims.
What is claimed is:

Claims

1. A hot melt adhesive composition comprising:
a thermoplastic component having a softening point of at least 120°C and selected from the group consisting of thermoplastic elastomers, thermoplastic polymers and combinations thereof;
a silane adhesion promoter having a flash point greater than 100°C at atmospheric pressure and a boiling point greater than 100°C at from 0.5 mmHg to 15 mmHg; and
optionally, a thermoplastic tackifying agent having a softening point greater than 80°C.
2. The hot melt adhesive composition of claim 1 , comprising:
from about 5 % by weight to about 35 % by weight of the thermoplastic tackifying agent.
3. The adhesive composition of claim 1 , further comprising a thermoplastic component having a softening point of less than 120°C.
4. A solar panel assembly comprising:
a solar panel;
a support; and
the hot melt adhesive composition of any one of claims 1 -3,
the support being bonded to the solar panel through the adhesive composition.
5. The solar panel assembly of claim 4, wherein the solar panel comprises a substrate comprising glass and a superstrate, the adhesive composition being in contact with the glass of the substrate.
6. The solar panel assembly of claim 4, wherein the solar panel comprises a substrate comprising polymer, the adhesive composition being in contact with the polymer of the substrate.
7. The solar panel assembly of claim 4, wherein the adhesive composition further comprises a spacer.
8. A method of adhering a component of a solar panel assembly to a solar panel, the method comprising:
contacting at least one of a first component and a second component with the adhesive composition of any one of claims 1 -3, the first component comprising a component of the solar panel assembly other than the solar panel, and the second component comprising the solar panel.
9. The method of claim 8, wherein the first component comprises at least one of a back rail, a frame, and a junction box. and the second component comprises a substrate of the solar panel, the substrate comprising at least one of polymer and glass.
10. The method of claim 8, wherein the first component comprises a metal back rail and the second component comprises a substrate of the solar panel, the substrate comprising at least one of polymer and glass.
1 1. The method of claim 10, wherein the adhesive composition further comprises spacer.
12. A framed solar panel assembly, comprising:
a solar panel comprising edges;
a peripheral frame comprising an interior surface; and a hot melt adhesive/sealant composition disposed between the interior surface of the frame and the edges of the panel, the panel being bonded to the frame through the adhesive/sealant composition, the adhesive/sealant composition comprising
a thermoplastic component having a softening point of at least 120°C and selected from the group consisting of thermoplastic elastomers, thermoplastic polymers and combinations thereof;
a silane adhesion promoter having a flash point greater than 100°C at atmospheric pressure and a boiling point greater than 100°C at from 0.5 raraHg to 15 inmHg; and
optionally, a thermoplastic tackifying agent having a softening point greater than 80°C.
13. The framed solar panel assembly of claim 12, wherein the adhesive/sealant composition exhibits an MVTR of no greater than 2 g/m /day.
14. A method of framing a solar panel, the method comprising:
contacting at least one of the interior surfaces of a frame with a solar panel by means of a hot melt adhesive/sealant composition, and
affixing the frame to the solar panel,
the adhesive/sealant composition comprising
a thermoplastic component having a softening point of at least 120°C;
a silane adhesion promoter having a flash point greater than 100°C at atmospheric pressure and a boiling point greater than 100°C at from 0.5 mmHg to 15 mmHg; and
optionally, a thermoplastic tackifying agent having a softening point greater than 80"C.
15. The method of claim 14, wherein the adhesive/sealant composition exhibits an MVTR of no greater than 2 g/nr/day.
PCT/US2011/027068 2010-03-05 2011-03-03 Thermally resistant hot melt adhesive composition, methods of using the sam, and solar panel assembly including the same WO2011109646A1 (en)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US31083410P 2010-03-05 2010-03-05
US31090410P 2010-03-05 2010-03-05
US31092810P 2010-03-05 2010-03-05
US61/310,904 2010-03-05
US61/310,928 2010-03-05
US61/310,834 2010-03-05

Publications (1)

Publication Number Publication Date
WO2011109646A1 true WO2011109646A1 (en) 2011-09-09

Family

ID=43982237

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2011/027068 WO2011109646A1 (en) 2010-03-05 2011-03-03 Thermally resistant hot melt adhesive composition, methods of using the sam, and solar panel assembly including the same

Country Status (1)

Country Link
WO (1) WO2011109646A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102610681A (en) * 2012-03-30 2012-07-25 江苏明昊新材料科技有限公司 Frame of solar photovoltaic module

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3792002A (en) * 1971-04-17 1974-02-12 Schering Ag Hot melt pressure sensitive adhesives
EP0845816A1 (en) * 1995-08-14 1998-06-03 Sunstar Giken Kabushiki Kaisha Solar cell module and its manufacturing method
WO1998058003A1 (en) * 1997-06-19 1998-12-23 H.B. Fuller Licensing & Financing, Inc. Thermoplastic moisture cure polyurethanes
US20040181007A1 (en) * 2003-03-13 2004-09-16 Margarita Acevedo Moisture curable, radiation curable sealant composition
US20040180155A1 (en) * 2003-03-13 2004-09-16 Nguyen-Misra Mai T. Moisture curable hot melt sealants for glass constructions
US20050222363A1 (en) * 2002-07-31 2005-10-06 Michael Krebs Segmented polyurethane hotmelt adhesives
US20090205703A1 (en) 2008-02-14 2009-08-20 Applied Materials, Inc. Apparatus and method of mounting and supporting a solar panel
US20100018570A1 (en) 2008-05-16 2010-01-28 Cashion Steven A Concentrating photovoltaic solar panel

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3792002A (en) * 1971-04-17 1974-02-12 Schering Ag Hot melt pressure sensitive adhesives
EP0845816A1 (en) * 1995-08-14 1998-06-03 Sunstar Giken Kabushiki Kaisha Solar cell module and its manufacturing method
WO1998058003A1 (en) * 1997-06-19 1998-12-23 H.B. Fuller Licensing & Financing, Inc. Thermoplastic moisture cure polyurethanes
US6355317B1 (en) 1997-06-19 2002-03-12 H. B. Fuller Licensing & Financing, Inc. Thermoplastic moisture cure polyurethanes
US20050222363A1 (en) * 2002-07-31 2005-10-06 Michael Krebs Segmented polyurethane hotmelt adhesives
US20040181007A1 (en) * 2003-03-13 2004-09-16 Margarita Acevedo Moisture curable, radiation curable sealant composition
US20040180155A1 (en) * 2003-03-13 2004-09-16 Nguyen-Misra Mai T. Moisture curable hot melt sealants for glass constructions
US20090205703A1 (en) 2008-02-14 2009-08-20 Applied Materials, Inc. Apparatus and method of mounting and supporting a solar panel
US20100018570A1 (en) 2008-05-16 2010-01-28 Cashion Steven A Concentrating photovoltaic solar panel

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102610681A (en) * 2012-03-30 2012-07-25 江苏明昊新材料科技有限公司 Frame of solar photovoltaic module

Similar Documents

Publication Publication Date Title
AU2004220035B2 (en) One-part moisture curable hot melt silane functional poly-alpha-olefin sealant composition
US7414090B2 (en) Low-temperature press process for making insulating glass assemblies
EP2798030B1 (en) High performance hotmelt window sealant
WO2011109605A1 (en) Thermally resistant reactive silane functional poly-alpha-olefin hot melt adhesive composition, methods of using the same, and solar panel assembly including the same
US9404004B2 (en) High performance hotmelt window sealant
WO2011109629A1 (en) Thermally resistant hot melt moisture cure polyurethane adhesive composition, methods of using the same, and solar panel assembly including the same
WO2011109646A1 (en) Thermally resistant hot melt adhesive composition, methods of using the sam, and solar panel assembly including the same
US10968371B2 (en) Moisture curable hot melt sealant composition including silane functional polyurethane
JP2011236331A (en) Hot melt sealing material composition

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 11709247

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 11709247

Country of ref document: EP

Kind code of ref document: A1