Classifications

• • 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
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function

Definitions

• Insulating glass assemblies such as insulating glass units and insulating sash assemblies often include a pair of glass sheets maintained in a fixed spaced relation to each other by a spacing and sealing structure that extends around the periphery of the inner facing surfaces of the glass sheets to define a sealed and insulating space between the glass sheets.
• the glass panes are adhered to the spacer that is an integral part of the sash frame.
• the glass sheets are usually attached to the structure by a sealant or adhesive composition.
• Dual-cure compositions in which ultraviolet light and moisture are used to cure the composition have been used in a variety of applications including, e.g., structural adhesives as described, e.g., in EP 646632A1, WO 0105846, and WO 98/53008.
• a two package UV curable conformal coating has been described in US 5,013,631.
• a photocurable resin composition for use in coatings comprising a component with dual functionality, acrylate and silane, is described in EP 0 549 228 Bl. This is a low molecular weight compound that is intended to improve adhesion at high temperatures.
• US 5,478,427 describes adhesives based on macromers having acrylate and isocyanate functionality, but in this case to achieve adhesion the composition has to be applied on both substrates to be bonded.
• the invention relates to an insulating glass assembly that includes at least two panes of glass, a spacer, and a sealant composition, said glass being bonded to said spacer through said sealant composition, said sealant composition comprising at least one of a) a moisture curable, radiation curable polyurethane prepolymer; or b) a blend comprising a moisture curable polyurethane prepolymer and a radiation curable prepolymer.
• the dual-cure sealant composition of the present invention includes a moisture curable and radiation curable polyurethane prepolymer, a blend of a moisture curable polyurethane prepolymer and a radiation curable polymer, or a combination thereof.
• the sealant composition develops an initial green strength through photopolymerizing or crosslinking of the ethylenically unsaturated groups on exposure to radiant energy.
• Preferred compositions exhibit significant initial green strength immediately after exposure to UV curing and maintain sufficient green strength even at higher temperatures, allowing the assembly constructions to be shipped immediately after manufacture. Such compositions thus provide an advantage over typical hot-melt sealant compositions.
• the green strength of the present compositions is built by polymerizing the acrylate double bonds, thus creating a network, even though lightly crosslinked, and not by a thermoplastic component that melts at the softening temperature of the compositions prior to being moisture cured.
• the final properties of the composition result from a subsequent reaction of the moisture curing functionalities with moisture.
• the sealant composition also preferably exhibits an elongation of at least about 80%, more preferably at least about 200%, and preferably exhibits a Tg less than about 10°C, more preferably less than about -10°C.
• the sealant composition also preferably has a slump of less than about 0.1 inch (about 2.5 mm) when tested in accordance with ASTM D- 2202.
• Radiation curable groups include ethylenically unsaturated groups, which include, e.g., (meth)acrylate, acryl groups (e.g., acrylamide and acryloxy), methacryl groups (e.g., methacrylamide and methacryloxy), and akenyl groups (e.g., vinyl, allyl, and hexenyl).
• ethylenically unsaturated groups include, e.g., (meth)acrylate, acryl groups (e.g., acrylamide and acryloxy), methacryl groups (e.g., methacrylamide and methacryloxy), and akenyl groups (e.g., vinyl, allyl, and hexenyl).
• the functional groups can be located pendant, terminal, or a combination thereof, to the polyurethane prepolymer.
• the functional groups are located terminally on the prepolymer, i.e., the prepolymer is endcapped with functional groups.
• Preferred moisture curable, radiation curable polyurethane prepolymers have a number average molecular weight (Mn) of from about 2000 to about 50,000, more preferably from about 2500 to about 20,000, most preferably from about 3000 to about 15,000 g/mole.
• the moisture curable, radiation curable polyurethane prepolymer preferably is polydisperse, i.e., the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (i.e., Mw/Mn) is at least about 1.8, preferably at least about 2.
• the moisture curable, radiation curable prepolymer is prepared by first reacting polyol and polyisocyanate to form an isocyanate functional prepolymer.
• the polyol is reacted with excess diisocyanate (i.e., the amount of isocyanate functional groups present in the reaction mixture is greater than the number of hydroxy equivalents present in the reaction mixture) in a first step to form an isocyanate functional polyurethane prepolymer.
• the ratio of isocyanate groups to hydroxy groups in the reaction mixture is sufficient to obtain an isocyanate concentration in the final prepolymer of from about 1% by weight to about 10% by weight, as measured by ASTM D-2572-80.
• suitable aminosilanes include phenyl amino propyl trimethoxy silane, methyl amino propyl trimethoxy silane, n-butyl amino propyl trimethoxy silane, t-butyl amino propyl trimethoxy silane, cyclohexyl amino propyl trimethoxy silane, dibutyl maleate amino propyl trimethoxy silane, dibutyl maleate substituted 4-amino 3,3-dimethyl butyl trimethoxy silane, amino propyl triethoxy silane and mixtures thereof, specific examples of which include N-methyl- 3-amino-2-methylpropyltrimethoxysilane, N-ethyl-3-amino-2- methylpropyltrimethoxysilane, N-ethyl-3-amino-2-methylpropyldiethoxysilane, N-ethyl-3- amino-2-methylpropyltriethoxysilane, N-ethyl
• Preferred isocyanato alkoxysilanes include, e.g., gamma-isocyanatopropyl-triethoxysilane and gamma-isocyanatopropyl-trimethoxysilane, commercially available examples of which are available under the trade designation SILQUEST A-35 and SILQUEST A-25 from OSi Specialties-Crompton Corp.
• the monofunctional alcohol is preferably present in the reaction mixture in an amount of less than about 10 molar %, more preferably less than about 5 molar %, based on the molar equivalents of isocyanate.
• the moisture curable polyurethane prepolymer is preferably present in the composition in an amount from about 1% by weight to about 40% by weight, more preferably from about 1% to about 20% by weight, and most preferably from about 3% by weight to about 10% by weight.
• Preferred acrylates are hydrophobic, predominantly of hydrocarbon structure, have a low Tg (preferably less than about 0°C, more preferably less than about - 10°C) and have sufficient compatibility with the moisture curable prepolymer.
• Preferred acrylated polymers are also substantially amorphous.
• Such acrylates are commercially available under the trade designations BAC-45 from San Esters Corporation, a distributor of Osaka Organic Chemicals (Osaka, Japan), and CN302 from Atofina Chemicals (Exton, PA).
• the radiation curable polymer is preferably present in the composition in an amount of greater than about 5% by weight, more preferably greater than about 15% by weight, most preferably greater than about 20% by weight.
• the composition also includes a non-reactive plasticizer.
• Suitable plasticizers include, e.g., phthalates, adipates, phosphates, trimellitates, dipropylene and diethylene glycol dibenzoates and mixtures thereof, and epoxidized soybean oil.
• Suitable commercially available plasticizers include the Jayflex plasticizers from Exxon Chemical, the DIOCTYL, SANTICIZER, and DIBUTYL plasticizers from Monsanto, and the ADFMOLL, DISFLAMOLL, MESAMOLL, UNIMOLL, TEGDA, TRIACETLN, and ULTRAMOLL plasticizers from Bayer.
• Preferred plasticizers have low volatility, such as long chain, branched phthalates (e.g., ditridecyl phthalate, di-L-nonyl phthalate, and di-L- undecyl phthalate), including the JAYFLEX DTDP and DIDP plasticizers.
• Useful dioctyl and diisodecyl phthalates include those available under the tradenames "Jayflex DOP" and “Jayflex DIDP" from Exxon Chemical.
• Useful dibenzoates are available under the trade designations BENZOFLEX 9-88, BENZOFLEX 50 and BENZOFLEX 400 from Velsicol Chemical Corporation.
• Soybean oil is commercially available, e.g., from Union Carbide Corporation under the trade designation FLEXOL EPO and polymeric plasticizers from Bayer under the tradenames ULTRAMOLL.
• the reactive plasticizer preferably has a molecular weight of from about 300 g/mol to about 10,000 g/mol, more preferably from about 500 g/mol to about 6000 g mol.
• the sealant composition is suitable for use in manufacturing insulating glass assemblies.
• the sealant composition is applied to a glazing surface, e.g., a surface on the spacer, the perimeter of the glass pane that is positioned over the spacer, or both.
• the sealant composition can be applied to the glazing surface using any suitable applicator including, e.g., a hand held glue gun, extruder, automated application equipment, e.g., a hand assist commercially available under the EACYPLY H1001 trade designation from Erdman Automation Corp. (Princeton, Minnesota).
• Sealant composition can also be applied simultaneously either horizontally or vertically to different portions of the spacer or the glass pane using at least two applicators.
• Test procedures used in the examples include the following.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Polyurethanes Or Polyureas (AREA)
• Sealing Material Composition (AREA)
• Compositions Of Macromolecular Compounds (AREA)

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• 2003
  • 2003-03-13 US US10/387,360 patent/US7189781B2/en not_active Expired - Lifetime
• 2004
  • 2004-03-11 EP EP04719785A patent/EP1601705A2/en not_active Withdrawn
  • 2004-03-11 WO PCT/US2004/007456 patent/WO2004083272A2/en not_active Ceased
  • 2004-03-11 JP JP2006507085A patent/JP4741469B2/ja not_active Expired - Fee Related

Non-Patent Citations (1)

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