Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F4/00—Polymerisation catalysts
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F4/00—Polymerisation catalysts
  • C08F4/42—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors
  • C08F4/44—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides
  • C08F4/52—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides selected from boron, aluminium, gallium, indium, thallium or rare earths
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
  • C07F5/00—Compounds containing elements of Groups 3 or 13 of the Periodic Table
  • C07F5/02—Boron compounds
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/28—Web or sheet containing structurally defined element or component and having an adhesive outermost layer
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/28—Web or sheet containing structurally defined element or component and having an adhesive outermost layer
  • Y10T428/2852—Adhesive compositions
  • Y10T428/2878—Adhesive compositions including addition polymer from unsaturated monomer
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31652—Of asbestos
  • Y10T428/31663—As siloxane, silicone or silane
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31855—Of addition polymer from unsaturated monomers

Definitions

• the invention is also directed to curable compositions made from the organosilicon functional boron amine catalyst complex.
• the invention is further directed to a composite article that includes the curable composition and at least one substrate.
• An additional feature of the invention relates to organosilicon compositions that can be cured at low temperatures wherein the curable composition contains a free radical polymerizable organopolysiloxane compound.
• the invention is directed to methods of making composite articles in which the curable composition is in the form of an adhesive that can be processed at a temperature lower than temperatures previously employed, and the substrate to which the adhesive is applied and the adhesive composition bond together at a lower temperature to make composite articles.
• M, D, T, and Q represent the functionality of the structural units of polyorganosiloxanes including organosilicon fluids, resins, and cured products thereof. These symbols are used in accordance with the established understanding in the silicone industry.
• M represents the monofunctional unit R3 SiO ⁇ /2
• D represents the difunctional unit R2Si ⁇ 2/2J
• T represents the trifunctional unit RSi ⁇ 3/2
• Q represents the tetrafunctional unit Si ⁇ 4/2-
• R represents an organic group. The structural formula of these units is shown below.
• Organoborane amine complexes are known.
• organoborane amine complexes used for the polymerization of acrylic monomers are described in US Patent 3,275,611 (September 27, 1966).
• Organoboron compounds such as trialkylboranes by themselves are pyrophoric in the presence of oxygen, so preformed complexes between organoboron compounds and amine compounds are noted to have the benefit of imparting improved stability to organoboron compounds such as trialkylboranes.
• Some recent developments in the structure of certain organoborane amine complexes are described in US Patent 6,706,831 (March 16, 2004), including the use of the complexes in acrylate based adhesives.
• the combination of alkylborane amine complexes with amine reactive decomplexing agents to initiate polymerization of acrylic adhesives at room temperature is also disclosed.
• the organoborane compound used to form the organoborane-amine complex is described as a trialkyl borane or an alkylcycloalkyl borane having the formula BR'3 where R' is a CJ.JO alkyl group, a 03. JQ cycloalkyl group, or a structure in which two or more of the R' groups combine to form a cycloaliphatic ring.
• R' is a CJ.JO alkyl group, a 03. JQ cycloalkyl group, or a structure in which two or more of the R' groups combine to form a cycloaliphatic ring.
• One limitation of such trialkylborane-based catalysts however is their tendency to bleed or bloom to the surface after curing has been completed because of limited compatibility with the matrix, particularly in the case of non-polar matrices such as silicones.
• the '512 patent also discloses known amine compounds containing silane or organosiloxane compounds for forming complexes with trialkylborane compounds.
• the grafting of silicon-containing groups on amine complexing agents can lead to improvements in certain properties including improved compatibility with silicones before cure, depending on the nature of the silicon-containing group.
• the boron compound remains unmodified such that many of the aforementioned limitations of prior art compositions remain.
• the '512 patent does not disclose any organoborane-amine catalysts where any of the R 1 groups attached to boron contain a silicon atom.
• curable organosilicon compositions and their uses are known including organopolysiloxane containing compositions.
• addition-curable materials since volatile byproducts are not generated during reactions in curing such materials.
• a suitable addition-curable material is a silicone based elastomer that cross-links upon cure by hydrosilylation.
• Such materials can be used for a variety of applications such as molded rubber parts, release coatings, pressure-sensitive adhesives, cure-in-place adhesives, and coatings or encapsulants for the protection and passivation of electronic circuit boards.
• hydrosilylation chemistry for curing materials such as these is limited because hydrosilylation catalysts including platinum are susceptible to poisoning or inhibition by small quantities of compounds containing nitrogen, phosphorous, sulfur, tin, and arsenic, that strongly associate with such catalysts. This results in the formation of improperly formed or uncured products and limits the type and concentration of additives that can be used to modify the hydrosilylation curable composition.
• active hydrogen as an alcohol, acid, and even water can react with the organohydrogenpolysiloxane to create undesirable side reactions.
• additives and impurities containing hydrosilylation catalyst inhibiting groups that may be present during the curing process tend to reduce the cure rate or the physical properties of the hydrosilylation curable composition.
• the inhibiting groups are present on the surface of a substrate, development of adhesion between the substrate and the hydrosilylation curable composition may require substantially higher cure temperatures than usual. In severe cases, adhesion and cure may even be prevented altogether by the presence of inhibiting groups.
• compositions using condensation curing catalysts are also known.
• US Patent 6,534,581 (March 18, 2003) describes certain compositions containing an organopolysiloxane with silicon bonded hydroxy groups, a crosslinking agent, an electrically conductive filler, and a condensation type catalyst. These compositions do not contain an easily poisoned hydrosilylation group catalyst, and so condensation curing organosilicon compositions offer the advantage of low temperature curing.
• condensation curing requires the diffusion of moisture and so condensation curable compositions can take a significantly longer time to cure in a confined geometry or in deep section.
• compositions can be cured in about 10-20 hours at room temperature or in less than about 16 hours at 70 °C.
• an extended cure time introduces costly delays in the manufacturing process.
• condensation curable compositions are capable of generating volatile by-products such as alcohols that lead to the formation of voids from out-gassing.
• the addition curable composition is free radical curable
• catalysts such as organic peroxides
• free radical cures initiated by organic peroxides are easily inhibited in the presence of atmospheric oxygen leading to uncured or poorly cured products, or undesirable decomposition by-products are generated.
• high temperatures are needed to develop adhesion with the existing addition curable organosilicon compositions, the out-gassing of entrained volatile materials such as water from the substrate or from within the curable composition leads to the formation of undesirable voids or bubbles in joints formed between the silicone based elastomer and the substrate to which it is applied.
• compositions of the prior art Due to the deficiencies associated with compositions of the prior art as noted above, there is a need for compositions that cure rapidly at lower temperatures and/or shorter times with improved surface properties, and that eliminate the need of pre-drying and external treatments of surfaces to which the compositions are applied. Also, due to deficiencies associated with organopolysiloxane based materials as noted above, there is a need for compositions that are able to cure rapidly at a lower temperature and/or shorter time with improved surface properties and resistance to common cure inhibitors, and that possess unique advantages in properties attributed by organosilicon based matrices in general.
• the feature that distinguishes the present invention from the prior art is in the discovery of certain organosilicon functional boron amine catalyst complexes in which the organoborane compound used in the complex contains at least one silicon atom.
• the invention relates to curable compositions utilizing such organosilicon functional boron amine catalyst complexes offering unique control of properties such as working time, storage stability, cure rate, surface cure, and extractable content. This is due to the presence of silane or siloxane units as attachments to the boron compound.
• organosilicon-based materials cured by this technique offer unique physical properties with improved adhesion over conventional addition curable organosilicon compositions.
• the invention is directed to organosilicon functional boron amine catalyst complexes that are useful for curing free-radical polymerizable monomers, oligomers, or polymers.
• the invention is also directed to curable compositions containing (i) the free radical polymerizable monomer, oligomer, or polymer and (ii) the organosilicon functional boron amine catalyst complex.
• the free radical polymerizable monomer, oligomer, or polymer can be (a) an organic compound or (b) an organosilicon monomer, oligomer, or polymer containing unsaturation and being capable of undergoing free radical polymerization.
• the curable composition may also contain (iii) an amine reactive compound having amine reactive groups, such as a mineral acid, Lewis acid, carboxylic acid, carboxylic acid derivative, carboxylic acid metal salt, isocyanate, aldehyde, epoxide, acid chloride, or sulphonyl chloride.
• the functional groups of the amine reactive compound can be borne by organic molecules or organometallic compounds such as organosilanes, organopolysiloxanes, organotitanates, or organozirconates.
• the amine reactive compound can be monomeric, oligomeric, or polymeric.
• the amine reactive compound (iii) may contain free radical polymerizable groups such as acrylic acid or polyacrylic acid.
• the amine reactive compound (iii) can be attached to solid particles such as ground silica, precipitated silica, calcium carbonate, carbon black, carbon nanoparticles, silicon nanoparticles, barium sulfate, titanium dioxide, aluminum oxide, boron nitride, silver, gold, platinum, palladium, alloys thereof; or base metals such as nickel, aluminum, copper, and steel.
• solid particles such as ground silica, precipitated silica, calcium carbonate, carbon black, carbon nanoparticles, silicon nanoparticles, barium sulfate, titanium dioxide, aluminum oxide, boron nitride, silver, gold, platinum, palladium, alloys thereof; or base metals such as nickel, aluminum, copper, and steel.
• the curable composition may also contain (iv) a component capable of generating a gas when mixed with compounds bearing active hydrogen and a catalyst. While the three ingredients are required for producing foamed products, one or more of them may already be present in some curable compositions.
• the ingredient capable of generating a gas can be a silicon hydride functional compound such as an organohydrogen polysiloxane; the compound bearing active hydrogen can be water, an alcohol, or a carboxylic acid; and catalyst can be platinum, a platinum group metal, tin, titanium, or zirconium.
• the curable compositions are useful in preparing composite articles of manufacture in which substrates are coated or bonded together with the curable composition and cured. Such curable compositions and composite articles prepared therefrom can be used in a wide range of applications, such as in electronics, automotive, construction, sports and recreation, consumer products, and medical industries. [0022]
• the organosilicon functional boron amine catalyst complex containing at least one silicon atom is capable of initiating polymerization or crosslinking of free radical polymerizable monomers, oligomers, or polymers, by the introduction of an amine reactive compound having amine reactive groups, and/or by heating.
• Curable compositions herein utilizing the new complex contain (i) a free radical polymerizable monomer, oligomer, or polymer and (ii) the organosilicon functional boron amine catalyst complex.
• an effective amount of (iii) an amine reactive compound having amine reactive groups can be included in the composition.
• Component (iii) should be capable of causing the organosilicon functional boron amine catalyst complex to dissociate.
• compositions not containing component (iii) those compositions can be heated to temperatures sufficient to cause the organosilicon functional boron amine catalyst complex to dissociate.
• These curable compositions offer rapid cure rates at low temperatures, particularly when component (iii) is included.
• the curable compositions are applied to at least one surface of a substrate.
• the process can be carried out by bonding the curable composition to a surface of the substrate at significantly lower temperatures, i.e., typically room temperature (RT) of 20-25 °C/68-77 °F, in shorter periods of time
• Component (i) can be an organic compound or an organometallic compound such as an organosilicon compound. In either case, it can be a single monomer, oligomer, or polymer containing unsaturation and capable of undergoing free radical polymerization. Mixtures of monomers, oligomers, and polymers can also be used. In many cases, it is preferred to use mixtures of monomer, oligomers, and polymers to impart the desired combination of bulk and surface properties such as cure rate, modulus, and adhesion. When component (i) is an organic compound, the selected compound will depend on the use of the cured product.
• organic compounds are described in US Patent 6,762,260 (July 13, 2004), including organic compounds such as 2-ethylhexylacrylate, 2-ethylhexylrnethacrylate, methylacrylate, methylmethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, glycidyl acrylate, glycidyl methacrylate, allyl acrylate, allyl methacrylate, stearyl acrylate, tetrahydrofurfuryl methacrylate, caprolactone acrylate, perfluorobutyl acrylate, perfluorobutyl methacrylate, IH, IH, 2H, 2H-heptadecafluorodecyl acrylate, [
• organic compounds include acrylate tipped polyurethane prepolymers prepared by reacting isocyanate reactive acrylate monomers, oligomers or polymers such as hydroxy acrylates with isocyanate functional prepolymers.
• acrylate tipped polyurethane prepolymers prepared by reacting isocyanate reactive acrylate monomers, oligomers or polymers such as hydroxy acrylates with isocyanate functional prepolymers.
• conductive monomers, dopants, oligomers, polymers, and macromonomers having an average of at least one free radical polymerizable group per molecule, and the ability to transport electrons, ions, holes, and/or phonons.
• an organosilicon compound when used as component (i), again the selected compound depends on the use of the cured product. Generally, it comprises organosilanes or organopolysiloxanes having on average at least one free radical polymerizable moiety.
• the organosilicon compound can be monomeric, oligomeric, polymeric, or it can be a mixture of monomers, and/or oligomers, and/or polymers. Higher molecular weight species of such free radical polymerizable compounds are often referred to in the art as macromonomers.
• the organosilicon compounds can contain mono-functional or multi-functional units in the free radical polymerizable group.
• the monomers and oligomers can be any monomer or oligomer normally used to prepare addition or condensation curable polymers, or they can be monomers or oligomers used in other types of curing reactions, provided they contain at least one free radical polymerizable group.
• Suitable organosilicon monomers include compounds having a structure generally corresponding to the formula R" n Si(OR'")4_ n , where n is 0-4; and where at least one of the R" or R" groups contains a free radical polymerizable group.
• the R" and R" groups can be independently, hydrogen; a halogen atom; or an organic group including alkyl groups, haloalkyl groups, aryl groups, haloaryl groups, alkenyl groups, alkynyl groups, acrylate functional groups, and methacrylate functional groups.
• the R" and R'" groups may also contain other organic functional groups including glycidyl groups, amine groups, ether groups, cyanate ester groups, isocyano groups, ester groups, carboxylic acid groups, carboxylate salt groups, succinate groups, anhydride groups, mercapto groups, sulfide groups, azide groups, phosphonate groups, phosphine groups, masked isocyano groups, and hydroxyl groups.
• organic functional groups including glycidyl groups, amine groups, ether groups, cyanate ester groups, isocyano groups, ester groups, carboxylic acid groups, carboxylate salt groups, succinate groups, anhydride groups, mercapto groups, sulfide groups, azide groups, phosphonate groups, phosphine groups, masked isocyano groups, and hydroxyl groups.
• free radical polymerizable organosilicon monomers include compounds such as methacryloxymethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, methacryloxymethyltriethoxysilane, 3-methacryloxypropyltriethoxysilane, acryloxymethyltrimethoxysilane,3- acryloxypropyltrimethoxysilane, methacryloxymethyltrimethylsilane, 3-methacryloxypropyltrimethylsilane, acryloxymethyltriethoxysilane, 3- acryloxypropyltriethoxysilane, acryloxymethyltrimethylsilane, 3-acryloxylpropyltrimethylsilane, vinyltrimethoxysilane, allyltrimethoxysilane, 1-hexenyltrimethoxysilane, tetra(allyloxysilane), tetra(3-butenyl-l-oxy)silane, tri(3-butoxybutoxysilane
• the preferred free radical polymerizable moieties for these organosilicon compounds are aliphatic unsaturated groups in which the double bond is located at the terminal positions, internal positions, or both positions relative to the functional group.
• the most preferred free radical polymerizable moiety for the organosilicon compounds are acrylate groups or methacrylate groups.
• the compound when the free radical polymerizable organosilicon component is a monomer, oligomer, or polymer, the compound can be an organopolysiloxane having a linear, branched, hyperbranched, or resinous structure.
• the compound can be homopolymeric or copolymeric.
• the free radical polymerizable moiety for the organopolysiloxane can be an unsaturated organic group such as an alkenyl group having 2-12 carbon atoms, exemplified by the vinyl group, allyl group, butenyl group, or the hexenyl group.
• the unsaturated organic group can also comprise alkynyl groups having 2-12 carbon atoms, exemplified by the ethynyl group, propynyl group, or the butynyl group.
• the unsaturated organic group can bear the free radical polymerizable group on an oligomeric or polymeric poly ether moiety such as an allyloxypoly(oxyalkylene) group or a halogen substituted analog thereof.
• the free radical polymerizable organic group can contain acrylate functional groups or methacrylate functional groups, exemplified by acryloxyalkyl groups such as 3-acryloxypropyl, 2- acryloxy ethyl, and acryloxymethyl, groups, and methacryloxyalkyl groups such as 3- methacryloxypropyl, 2-acryloxyethyl, and acryloxymethyl groups.
• the unsaturated organic groups can be located at the terminal positions, pendant positions, or both the terminal and pendant positions relative to the polymer backbone.
• the preferred free radical polymerizable moiety for monomeric, oligomeric, and polymeric organosilicon compounds are acrylate groups and methacrylate groups.
• any remaining silicon bonded organic groups can be monovalent organic groups free of aliphatic unsaturation.
• the monovalent organic group can have 1-20 carbon atoms, preferably 1-10 carbon atoms, and is exemplified by alkyl groups such as methyl, ethyl, propyl, pentyl, octyl, undecyl, and octadecyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl, tolyl, xylyl, benzyl, and 2-phenylethyl; alkyloxypoly(oxylalkylene) groups such as propyloxypoly(oxyethylene), propyloxypoly(oxypropylene), propyloxy-poly(oxypropylene)-co-poly(oxyethylene) groups, halogen substituted analogs thereof; cyanofunctional groups including cyanoalkyl groups such as cyanoethyl and cyanoprop
• the free radical polymerizable organosilicon compound can vary in consistency from a fluid having a viscosity of 0.001 Pa-s at 25 °C to a gum.
• the free radical polymerizable organosilicon compound can also be a solid that becomes flowable at an elevated temperature or by the application of shear.
• Component (i) includes organopolysiloxane fluids having the formulae: (a) Rl 3 SiO(R ⁇ SiO) 11 (RlR 2 SiOkSiR 1 S,
• a has an average value of zero to 20,000
• b has an average value of 1-20,000
• c has an average value of zero to 20,000
• d has an average value of zero to 20,000.
• Each Rl group is independently a monovalent organic group.
• the R ⁇ group is independently an unsaturated monovalent organic group.
• the R ⁇ groups can be the same as the RI groups.
• Each R ⁇ is independently an unsaturated organic group.
• Suitable R* groups are monovalent organic groups including acrylic functional groups such as acryloxymethyl, 3-acryloxypropyl, methacryloxymethyl and 3- methacryloxypropyl, groups; alkyl groups such as methyl, ethyl, propyl, and butyl groups; alkenyl groups such as vinyl, allyl, and butenyl groups; alkynyl groups such as ethynyl and propynyl groups; aromatic groups such as phenyl, tolyl, and xylyl groups; cyanoalkyl groups such as cyanoethyl and cyanopropyl groups; halogenated hydrocarbon groups such as 3,3,3- trifluoropropyl, 3-chloropropyl, dichlorophenyl, and 6,6,6,5, 5,4,4,3,3-nonafluorohexyl groups; alkenyloxypoly(oxyalkyene) groups such as allyloxy(polyoxyethylene), allyloxypoly
• the R ⁇ group is exemplified by alkenyl groups such as vinyl, allyl, and butenyl groups; alkynyl groups such as ethynyl and propynyl groups; and acrylic functional groups such as acryloxymethyl, 3-acryloxypropyl, methacryloxymethyl and methacryloxypropyl groups.
• alkenyl groups such as vinyl, allyl, and butenyl groups
• alkynyl groups such as ethynyl and propynyl groups
• acrylic functional groups such as acryloxymethyl, 3-acryloxypropyl, methacryloxymethyl and methacryloxypropyl groups.
• the R ⁇ groups can be the same as the Rl groups.
• the R ⁇ group is exemplified by alkenyl groups such as vinyl, allyl, and butenyl groups; alkynyl groups such as ethynyl and propynyl groups; alkenyloxypoly(oxyalkyene) groups such as allyloxy(polyoxyethylene), allyloxypoly(oxypropylene), and allyloxy-poly(oxypropylene)- co-poly(oxyethylene) groups; and acrylic functional groups such as acryloxymethyl, 3- acryloxypropyl, methacryloxymethyl and 3 -methacryloxypropyl groups.
• alkenyl groups such as vinyl, allyl, and butenyl groups
• alkynyl groups such as ethynyl and propynyl groups
• alkenyloxypoly(oxyalkyene) groups such as allyloxy(polyoxyethylene), allyloxypoly(oxypropylene), and allyloxy-poly(oxypropylene
• organopolysiloxane fluids suitable for use as component (i) include ⁇ , ⁇ -methacryloxymethyl-dimethylsilyl terminated polydimethylsiloxanes, ⁇ , ⁇ - methacryloxypropyl-dimethylsilyl terminated polydimethylsiloxanes; ⁇ , ⁇ -acryloxymethyl- dimethylsilyl terminated polydimethylsiloxanes, ⁇ , ⁇ -acryloxypropyl-dimethylsilyl terminated polydimethylsiloxanes; pendant acrylate functional polymers and methacrylate functional polymers such as poly(acryloxymethyl-methylsiloxy)-polydimethylsiloxane copolymers, poly(acryloxypropyl-methylsiloxy)-polydimethylsiloxane copolymers, poly(methacryloxymethyl-methylsiloxy)-polydimethylsiloxane copolymers, and poly(methacryloxypropyl-methyl
• organopolysiloxane fluids differing in their degree of functionality and/or the nature of the free radical polymerizable group.
• a much faster cure rate and a reduced sol content can be obtained by using a tetra-functional telechelic polydimethylsiloxane prepared by the Michael addition reaction of N-(methyl)isobutyl-dimethylsilyl terminated polydimethylsiloxane with two molar equivalents of trimethylolpropane tri-acrylate as component (i) of the composition, relative to di-functional methacryloxypropyl-dimethylsilyl terminated polydimethylsiloxanes having a similar degree of polymerization (DP).
• DP degree of polymerization
• compositions allow better working time and produce a lower modulus elastomer.
• combinations combinations of component (i) having differing structures may be beneficial.
• Methods for preparing such organopolysiloxane fluids include the hydrolysis and condensation of the corresponding organohalosilanes or the equilibration of cyclic polydiorganosiloxanes.
• Component (i) can be an organosiloxane resin including MQ resins containing R ⁇ SiOj /2 units and Si ⁇ 4/2 units; TD resins containing R ⁇ Si ⁇ 3/2 units and R ⁇ 2Si ⁇ 2/2 units; MT resins containing R ⁇ SiO 1/2 units and R ⁇ Si ⁇ 3/2 units; MTD resins containing
• Each R ⁇ group in these organosiloxane resins represents a monovalent organic group.
• the monovalent organic group R-> can have 1-20 carbon atoms, preferably 1-10 carbon atoms.
• suitable monovalent organic groups representative of the R ⁇ group include acrylate functional groups such as acryloxyalkyl groups; methacrylate functional groups such as methacryloxyalkyl groups; cyanofunctional groups; and monovalent hydrocarbon groups.
• Monovalent hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, pentyl, octyl, undecyl, and octadecyl groups; cycloalkyl groups such as cyclohexyl groups; alkenyl groups such as vinyl, allyl, butenyl, and hexenyl groups; alkynyl groups such as ethynyl, propynyl, and butynyl groups; aryl groups such as phenyl, tolyl, xylyl, benzyl, and 2-phenylethyl groups; halogenated hydrocarbon groups such as 3,3,3-trifluoropropyl, 3-chloropropyl, dichlorophenyl, and 6,6,6,5,5,4,4,3,3-nonafmorohexyl groups; and cyano-functional groups including cyanoalkyl groups such as cyanoethyl and cyanopropy
• the R ⁇ group can also comprise an alkyloxypoly(oxyalkyene) group such as propyloxy(polyoxyethylene), propyloxypoly(oxypropylene) and propyloxy-poly(oxypropylene)-co-poly(oxyethylene) groups; halogen substituted alkyloxypoly(oxyalkyene) groups such as perfluoropropyloxy(polyoxyethylene), perfluoropropyloxypoly(oxypropylene) and perfluoropropyloxy-poly(oxypropylene)-co-poly(oxyethylene) groups; alkenyloxypoly(oxyalkyene) groups such as allyloxypoly(oxyethylene), allyloxypoly(oxypropylene) and allyloxy-poly(oxypropylene)-co-poly(oxyethylene) groups; alkoxy groups such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy and ethy
• the organosiloxane resin can contain an average of 1 -40 mole percent of free radical polymerizable groups such as unsaturated organic groups.
• the unsaturated organic groups may be an alkenyl group, alkynyl group, acrylate-functional group, methacrylate- functional group, or a combination of such groups.
• the mole percent of unsaturated organic groups in the organosiloxane resin is considered herein to be the ratio of (i) the number of moles of unsaturated groups containing siloxane units in the resin, to (ii) the total number of moles of siloxane units in the resin, times a factor of 100.
• organosiloxane resins that are useful as component (i) are MMethacryloxymethylQ resins, jVjMethacryloxypropylq re sins, MTMethacryloxymethyl ⁇ resins, MTMethacryloxypropyl ⁇ resins, MD ⁇ e& ⁇ a ⁇ y m ⁇ yh ⁇ y ] ⁇ resins, MDTMethacry ⁇ xypropy ⁇ TPheny ⁇ T resins, M ⁇ T ⁇ ny 1 resins, TT Methacr yloxymethyl resins, TTMe ⁇ a ⁇ oxypropy 1 resins, ⁇ Phenyl ⁇ Methacryloxymethyl re sins, ⁇ Phenyl ⁇ Methacryloxypropyl resins
• Methods of preparing such organosiloxane resins are known including resins made by treating a resin copolymer produced by a silica hydrosol capping process, with an alkenyl containing endblocking reagent, as described in US Patent 2,676,182 (April 20, 1954).
• This method involves reacting a silica hydrosol under acidic conditions with a hydrolyzable triorganosilane such as trimethylchlorosilane, a siloxane such as hexamethyldisiloxane, or a mixture thereof, followed by recovery of a copolymer having M and Q units.
• the copolymer typically contains about 2-5 percent by weight of hydroxyl groups.
• Organosiloxane resins containing less than 2 percent by weight of silicon bonded hydroxyl groups may then be prepared by reacting the copolymer with an endblocking agent containing unsaturated organic groups, and with an endblocking agent free of aliphatic unsaturation, in an amount sufficient to provide 3-30 mole percent of unsaturated organic groups in the product.
• endblocking agents include silazanes, siloxanes, and silanes; and preferred endblocking agents are described in US Patent 4,584,355 (April 22, 1986), US Patent 4,585,836 (April 29, 1986), and US Patent 4,591,622 (May 22, 1986).
• a single endblocking agent or a mixture of endblocking agents may be used to prepare such organosiloxane resins.
• organosilicon compound that can be used as component (i) is a composition formed by copolymerizing an organic compound having a polymeric backbone, with an organopolysiloxane, where an average of at least one free radical polymerizable group is incorporated per molecule.
• Some suitable organic compounds include hydrocarbon based polymers such as polyisobutylene, polybutadienes, and polyisoprenes; polyolefms such as polyethylene, polypropylene and polyethylene polypropylene copolymers; polystyrenes; styrene butadiene; and acrylonitrile butadiene styrene; polyacrylates; polyethers such as polyethylene oxide or polypropylene oxide; polyesters such as polyethylene terephthalate or polybutylene terephthalate; polyamides; polycarbonates; polyimides; polyureas; polymethacrylates; and partially fluorinated or perfluorinated polymers such as polytetrafluoroethylene; fluorinated rubbers; terminally unsaturated hydrocarbons, olefins and polyolefins.
• hydrocarbon based polymers such as polyisobutylene, polybutadienes, and polyisoprenes
• polyolefms such as poly
• the organic compound can be a copolymer of any of these compounds, including polymers containing multiple organic functionality, multiple organopolysiloxane functionality, or combinations of organopolysiloxanes and organic compounds.
• the copolymeric structures can vary in the arrangement of repeating units from random, grafted, to being blocky in nature.
• Component (i) in addition to bearing on average at least one free radical polymerizable group, may have a physical transition temperature, bear an organofunctional group with a physical transition temperature, or upon curing form matrices that have a physical transition temperature, i.e., glass transition or melting transition, such that the composition undergoes changes marked by a softening or non-linear reduction in its viscosity on reaching certain temperatures under the conditions of use.
• Such organopolysiloxane matrices are useful for phase change compositions such as those found to be useful in thermal interface materials for electronic components.
• the organopolysiloxane matrix may be an organofunctional silicone wax.
• the wax can be an uncrosslinked organofunctional silicone wax, a crosslinked organofunctional silicone wax, or a combinations of waxes. Silicone waxes such as these are commercially available and are described in US Patent 6,620,515 (September 16, 2003). When the organofunctional silicone wax bears at least one free radical polymerizable group such as an acrylate or methacrylate group, it is useful to impart phase changes when used as component (i).
• Component (i) can also comprise a mixture of any of the organic compounds, organosilicon compounds, and/or organopolysiloxane compounds described above.
• the organosilicon functional boron amine catalyst complex (ii) is a complex formed between an organoborane compound containing at least one silicon atom, and a suitable amine compound that renders the complex stable under conditions of use, preferably under ambient conditions.
• Organosilicon is defined herein as meaning any silicon atom containing group, siloxane oligomer containing group, or siloxane polymer containing group.
• the complex has the formula:
• B represents boron
• R6, R7, and R8 are groups that can be independently selected from hydrogen; a cycloalkyl group; a linear or branched alkyl group having 1-12 carbon atoms on the backbone; an alkylaryl group; an organosilane group such as an alkylsilane or an arylsilane group; an organosiloxane group; an alkylene group capable of functioning as a covalent bridge to another boron atom; a divalent organosiloxane group capable of functioning as a covalent bridge to another boron atom; or halogen substituted homologues thereof.
• At least one of the R6, R7, or R8 groups contains one or more silicon atoms, and the silicon-containing group is directly, i.e., covalently, attached to boron.
• R9, RlO, and Rl 1 are a group that yields an amine compound or a polyamine compound capable of complexing boron, such as hydrogen, an alkyl group containing 1-10 carbon atoms, a halogen substituted alkyl group containing 1-10 carbon atoms, or an organosilicon functional group.
• the silicon containing group is such that the boron atom is separated from the nearest silicon atom by at least one covalent bond, and more preferably by at least two covalent bonds.
• the organosilicon functional boron portion of the complex contains a silane or a siloxane functionality. It can comprise any group containing both silicon and boron atoms. The boron and silicon atoms can be linked by any carbon, nitrogen, sulfur, or oxygen containing group.
• the organosilicon functional boron portion of the complex is the portion R6R7R8B of the complex where B represents boron; and R6, R7, and R8 are the groups as defined above. [0046] Some examples of groups suitable as R6, R7, and R8 groups include
• CH 2 CH-(CH 2 ) x -(Si(Riv) 2 -O) y Si(Ri v ) 2 -(CH 2 ) x -CH 2 -CH 2 -.
• x is zero to
• R6, R7, or R8 groups combine to form heterocyclic structures with the boron atom
• suitable groups include -CH 2 CH 2 CH 2 Si(Ri V ) 2 CH 2 CH 2 CH 2 -; -CH 2 CH 2 Si(Ri V ) 2 CH 2 CH 2 -; and -CH 2 CH 2 Si(Ri V ) 2 OSi(R 1V ) 2 CH 2 CH 2 -.
• R lv group examples include hydrogen; halogen; alkyl groups such as methyl, ethyl, propyl, and butyl groups; alkenyl groups such as vinyl, allyl, and butenyl groups; acrylic functional groups such as acryloxymethyl, 3- acryloxypropyl, methacryloxymethyl, and 3-methacryloyloxypropyl groups; alkynyl groups such as ethynyl and propynyl groups; aromatic groups such as phenyl, tolyl, and xylyl groups; cyanoalkyl groups such as cyanomethyl, cyanoethyl and cyanopropyl groups; halogenated hydrocarbon groups such as 3,3,3-trifluoropropyl, 3-chloropropyl, dichlorophenyl, and 6,6,6,5,5,4,4,3,3-nonafluorohexyl groups; alkenyloxypoly(oxyalkyene)
• organosilicon functional boron compounds that can be used to form the complex include the following three compounds, in which y has the same value as defined above: Organosilicon Functional Boron Compound 9
• the heterocyclic structures can be synthesized by techniques such as illustrated in the following reaction scheme as exemplified by the following scheme where 9-BBN represents 9-borabicyclo[3,3,l]nonane.
• 9-BBN represents 9-borabicyclo[3,3,l]nonane.
• the bicyclic ring is depicted as commonly shown in chemical literature relating to boron compounds, and reference may be had to The Journal of Organic Chemistry, 1980, Volume 45, Pages 3571-3578, in the paper entitled Convenient and Regiospeci ⁇ c Route to Functionalized Organosilanes through Hydroboration ofAlkenylsilanes, by John A. Soderquist and Herbert C. Brown.
• organosilicon functional boron compounds that can be used to complex with an amine reactive compound to form the complex is shown below.
• the organosilicon functional boron compound is directly bonded to an organopolysiloxane through a bridge of at least two covalent bonds.
• the boron atom may be attached to silicon at terminal or pendant locations:
• Rl 2 is hydrogen, a halogen, an alkyl group, an alkoxy group, a cycloalkyl group, an aryl group, a halogen substituted alkyl group or a halogen substituted cycloalkyl group, or the group -B(Rl 5)2- When Rl 2 is -B(Rl 5)2, then e and h should have a value of at least one and not more than twelve.
• Rl 3 is hydrogen, a halogen, a branched or linear alkyl group, or a halogen-substituted linear or halogen-substituted branched alkyl group.
• Rl 4 represents the same type of groups as previously defined for R ⁇ ⁇ .
• the Rl 5 groups represent the same type of groups as previously defined for the R6, R7, and R8 groups.
• the values of e, f, and h are each zero to 20; the value of g is 1-20,000; and the value of i is 1-12.
• the article by Soderquist and Brown noted above, and the references cited therein, provide numerous examples and detailed synthetic routes for making the organosilicon functional borane part of the boron amine catalyst complex through hydroboration reactions. For example, one facile general route involves the reaction of a borane-tetrahydrofuran complex with a terminally unsaturated organosilicon compound.
• the organosilicon functional borane compound is such that at least 20 mol percent, more preferably at least 50 mol percent, of the organosilicon-functional groups attached directly to boron, are derived from the ⁇ terminal adduct.
• the amine portion of the complex may be provided by a variety of amines having at least one amine group including polyamines, cyclic amines, and blends of different amine groups.
• the amine may be a primary or secondary amine.
• amine compounds useful to form the amine portion of the complex include ethylamine, n-butylamine, 1,3 propane diamine, 1,6-hexanediamine, methoxypropylamine, pyridine, and isophorone diamine. Other specific examples of amine compounds are described in such patents.
• Silicon containing amine compounds can also be used to form the complex such as aminomethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, aminomethyltriethoxysilane, 3 -aminopropyltriethoxysilane, 2-(trimethoxysilylethyl)-pyridine, aminopropylsilanetriol,
• Amine functional organopolysiloxanes are also useful for forming the complex including compounds described above in formulas (a) and (b), and compounds previously described for the organopolysiloxane resins.
• the amine functional organopolysiloxane must contain at least one amine functional group, representative of which are aminomethyl, 2- aminoethyl, 3-aminopropyl, 6-aminohexyl, 11-aminoundecyl, 3-(N-allylamino)propyl, N-(2- aminoethyl)-3-aminopropyl, N-(2-aminoethyl)-3-aminoisobutyl, p-aminophenyl, 2- ethylpyridine, and 3-propylpyrrole.
• terminal and/or pendant amine-functional polydimethylsiloxane oligomers and polymers terminal and/or pendant amine-functional random, graft and block copolymers and co-oligomers of polydimethylsiloxane and poly(3,3,3 trifluoropropyl-methylsiloxane), terminal and/or pendant amine-functional random, graft and block copolymers and co-oligomers of polydimethylsiloxane and poly(6,6,6,5,5,4,4,3,3-nonfluorohexyl-methylsiloxane), and terminal and/or pendant amine-functional random, graft and block copolymers and co- oligomers of polydimethylsiloxane and polyphenymethylsiloxane.
• useful compounds include resinous amine-functional siloxanes such as the amine-functional compounds described previously as organopolysiloxane resins.
• resinous amine-functional siloxanes such as the amine-functional compounds described previously as organopolysiloxane resins.
• other nitrogen containing compounds including N-(3-triethyoxysilylpropyl)-4,5-dihydroimidazole, ureidopropyltriethoxysilane, siloxanes of formulas similar to formulas (a) and (b) noted above, and those compounds described previously as organopolysiloxane resins in which at least one group is an imidazole, amidine, or ureido functional group.
• the molecular weight is not limited except that it should be sufficient to maintain a high concentration of boron in order to permit curing or polymerization of the composition.
• the part containing the organoborane initiator may be diluted with other components of the composition, or it may comprise the initiator complex alone.
• the curable composition may be stabilized by physically or chemically attaching the organoborane amine complex to solid particles. This provides a way to control working times, as well as to stabilize liquid phase organoborane amine complexes against separating from the rest of the composition during storage.
• chemical attachment can be performed by pretreating solid particles such as ground silica, precipitated silica, calcium carbonate, or barium sulfate, with a condensation reactive compound containing an amine group such as aminopropyltrimethoxysilane.
• the pretreatment is followed by complexation with an organoborane compound, or by the direct treatment of the solid particles using a preformed organoborane amine complex that is condensation reactive.
• additives such as surface treating agents or impurities that are inherently amine reactive, require appropriate pre-cautions to avoid premature decomplexation of the organoborane amine complex being attached.
• Solid particles containing amine reactive substances can be purified or neutralized before attachment of the organoborane amine complex.
• the attachment of the organoborane amine complex can be performed in an oxygen free environment.
• the curable composition may contain an amine reactive compound (iii) that is capable of initiating the polymerization or crosslinking when mixed with the organosilicon functional boron amine catalyst complex (ii) and exposed to an oxygenated environment.
• the amine reactive compound may be a liquid, gas, or solid.
• the amine reactive compound may be a small molecule, a monomer, an oligomer, a polymer, or a mixture thereof, and may also be diluted or borne by a carrier such as an aqueous or non-aqueous solvent, or by a filler particle.
• the amine reactive compound may contain free radical polymerizable groups or other functional groups such as a hydrolyzable group.
• the amine reactive groups on the amine reactive compound may be borne on an organic, organosilicon, or organopolysiloxane compound.
• the presence of component (iii) allows initiation of polymerization or crosslinking to occur at temperatures below the dissociation temperature of the organosilicon functional boron amine catalyst complex (ii), including room temperature and below.
• components (ii) and (iii) be physically or chemically isolated.
• curable compositions containing components (i), (ii), and (iii) can be rendered air stable by packaging component (iii) separately from component (ii) in multi-component formulations.
• components (ii) or (iii), or both components (ii) and (iii) can be encapsulated, or delivered in separate phases. This may be accomplished by introducing one or both of components (ii) and (iii) in a solid form or forms that prevents intimate mixing of components (ii) and (iii).
• Curing of the curable composition can be activated by heating it above the softening temperature of the solid phase component or encapsulant, or by introducing a solubilizing agent that allows mixing of components (ii) and (iii).
• Components (ii) and (iii) can also be combined in a single container without the occurrence of significant polymerization or crosslinking, by packaging the components (ii) and (iii) in a container where the mixing conditions are anaerobic.
• amine reactive compounds having amine reactive groups capable of rapidly initiating polymerization or curing in the presence of oxygen include mineral acids; Lewis acids; carboxylic acids; carboxylic acid derivatives such as anhydrides and succinates; carboxylic acid metal salts; isocyanates; aldehydes; epoxides; acid chlorides; and sulphonyl chlorides.
• Suitable amine reactive compounds include acrylic acid, methacrylic acid, polyacrylic acid, polymethacrylic acid, methacrylic anhydride, polymethacrylic anhydride, undecylenic acid, oleic acid, lauric acid, lauric anhydride, citraconic anhydride, ascorbic acid (Vitamin C), methylene bis-(4-cyclohexylisocyanate) monomers or oligomers, hexamethylene diisocyanate monomers or oligomers, toluene-2,4-diisocyanate monomers or oligomers, methylene diphenyl isocyanate monomers or oligomers, isophorone diisocyanate monomers or oligomers, (methacryloyl)isocyanate, 2-(methacryloyloxy)ethyl acetoacetate, undecylenic aldehyde, and dodecyl succinic anhydride.
• the amine reactive compound comprise an organosilane, or an organopolysiloxane having amine reactive groups.
• Some examples include 3-isocyanatopropyltrimethoxysilane; 3-glycidoxypropyltrimethoxysilane; propylsuccinic anhydride functionalized linear, branched, resinous, and hyperbranched organopolysiloxanes; cyclohexenyl anhydride functional linear, resinous, and hyperbranched organopolysiloxanes; carboxylic acid functionalized linear, branched, resinous, and hyperbranched organopolysiloxanes such as carboxydecyl terminated oligomeric or polymeric polydimethylsiloxanes; and aldehyde functionalized linear, branched, resinous, and hyperbranched organopolysiloxanes such as undecylenic aldehyde-terminated oligomeric or polymeric polydimethylsiloxanes.
• the '512 patent describes other silicon containing compounds that can be used, including compounds that release an acid when exposed to moisture.
• the '512 patent discloses other types of amine reactive decomplexation agents that can be used.
• Other compounds that can be used include compounds capable of generating amine reactive groups when exposed to ultraviolet radiation such as a photoacid generator.
• the curable composition can be stabilized by attaching the amine reactive compound to solid particles. This procedure enables one to control the working time, and it stabilizes the liquid phase containing the amine reactive compound against separation from the rest of the curable composition during storage. Attachment of the amine reactive compound to the solid particles can be accomplished by known surface treatment techniques that can be carried out in-situ or a priori.
• Some surface treatment methods include using a condensation reactive compound to pre-treat solid particles such as ground or precipitated silica, calcium carbonate, carbon black, carbon nanoparticles, silicon nanoparticles, barium sulfate, titanium dioxide, aluminum oxide, zinc oxide, boron nitride, silver, gold, platinum, palladium, and alloys thereof; or to pre-treat base metals such as nickel, aluminum, copper, and steel.
• a condensation reactive compound to pre-treat solid particles such as ground or precipitated silica, calcium carbonate, carbon black, carbon nanoparticles, silicon nanoparticles, barium sulfate, titanium dioxide, aluminum oxide, zinc oxide, boron nitride, silver, gold, platinum, palladium, and alloys thereof; or to pre-treat base metals such as nickel, aluminum, copper, and steel.
• the pretreatment is followed by reaction of the pre-treated solid particles with a compound having amine reactive groups, or by the direct treatment of the pre-treated solid particles with an amine
• condensation reactive compounds include isocyanatomethyltriethoxysilane, 3- isocyanatopropyltriethoxysilane, isocyanatomethyltrimethoxysilane, 3- isocyanatopropyltrimethoxysilane, triethoxysilylundecanal, glycidoxymethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, (triethoxysilyl)methylsuccinic anhydride, 3-(triethoxysilyl)propylsuccinic anhydride, and 2-(4-chlorosulfonylphenyl)ethyltrimethoxysilane.
• Attachment of the amine reactive compound to the solid particles can also be accomplished by mixing an acid functional compound with solid particles having an appropriate surface functionality under conditions conducive to formation of an acid base complex, a hydrogen bonded complex, or an acid salt.
• Some fillers are commercially available and are already pre-treated with surface treating agents referred to as lubricants, or can be obtained with impurities that contain amine reactive groups such as carboxylic acid. In this way, component (iii) can be delivered together in the form of a treated filler.
• the advantage obtained in that instance is that the reaction between the organoborane amine complex and the amine reactive groups on the filler can help remove the lubricant from the surface of the filler particles. It may also be advantageous for the sake of stability to use a combination of fillers containing amine reactive groups, and fillers that are inert with respect to amine compounds.
• amine reactive groups useful (iii) include carboxylic acid, anhydride, isocyanate, aldehydes, and epoxies. Blocked isocyanates may be useful in cases where instead of ambient polymerization, it is desirable to use heat to initiate polymerization rapidly.
• Cured compositions can be prepared in the form of a porous foam by including in the curable composition (iv) a component capable of generating a gas.
• a component capable of generating a gas typically contain a silicon hydride functional compound as the main component (iv), a compound bearing active hydrogen such as water, an alcohol, or carboxylic acid, and a co- catalyst such as platinum or tin.
• the co-catalyst facilitates the reaction of the silicon hydride and the compound bearing active hydrogen. Hydrogen gas is generated during the curing step and foam is generated.
• the foamed compositions can vary from flexible foams to rigid foams, depending on the particular silicon hydride, active hydrogen compound, and free radical polymerizable monomer, oligomer, or polymer that were used.
• the pore size distribution of the foam can be controlled by known methods of foam generation to tailor it relative to modulus, density, and permeability.
• Some ingredients that can be included in the curable compositions herein include fillers such as reinforcing fillers, extending fillers, electrically conductive fillers, and thermally conductive fillers; adhesion promoters; crosslinking agents; combinations of polymers, crosslinkers and catalysts useful for providing a secondary cure of the matrix; polymers capable of extending, softening, reinforcing, toughening, modifying viscosity, or reducing volatility when mixed into the composition; spacers; dyes; pigments; UV stabilizers; aziridine stabilizers; void reducing agents; cure modifiers such as hydroquinone and hindered amines; free radical initiators such as organic peroxides and ozonides; organoborane-amine complexes not containing silicon in the organoborane portion of the complex; comonomers such as organic acrylates and methacrylates; polymers; diluents; rheology modifiers; acid acceptors; antioxidants; oxygen sca
• electrically conductive fillers that can be used as an optional ingredient include metal particles, conductive non-metal particles, metal particles having an outer surface of a metal, or conductive non-metal particles having an outer surface of a metal.
• the outer surface metal can be silver, gold, platinum, palladium, nickel, aluminum, copper, or steel.
• thermally conductive fillers that can be used as an optional ingredient include metal particles, metal oxide particles, thermally conductive non-metal powders, or combinations thereof.
• the thermally conductive filler can be aluminum, copper, gold, nickel, silver, alumina, magnesium oxide, beryllium oxide, chromium oxide, titanium oxide, zinc oxide, barium titanate, diamond, graphite, carbon nanoparticles, silicon nanoparticles, boron nitride, aluminum nitride, boron carbide, titanium carbide, silicon carbide, tungsten carbide, or combinations thereof.
• Curable composition according to the invention can be prepared by combining and mixing: A. 1-100 parts by weight of (i) the free radical polymerizable monomer, oligomer or polymer;
• the working time and extension of shelf stability of curable compositions of the invention can be controlled by introducing additional amine compounds to increase the molar ratio of the amine groups to boron atoms in the composition.
• the effective amount to be added depends on the amine:boron ratio used in component (ii). It is preferred that the overall amine :boron ratio remain sufficiently low to permit polymerization to occur.
• a suitable amine:boron ratio would be less than 10:1, preferably less than 4:1.
• amine reactive compound (iii) When the amine reactive compound (iii) is already present in the curable composition, for example when residual carboxylic acid is present on filler particles, a higher level of amine compounds may be added to neutralize or partially neutralize the amine reactive groups for storage stability.
• the amine compound may contain mono-functional or multi-functional amine groups, and it can comprise a primary amine, secondary amine, and/or tertiary amine.
• the amine compound can contain free radical polymerizable groups or other functional group such as hydrolyzable groups.
• the amine reactive compound can be monomeric, oligomeric, or polymeric. Amine groups may be borne on an organic, organosilicon, or organopolysiloxane compound.
• Composite articles according to the invention preferably comprise curable compositions that are disposed or applied to a single substrate or between multiple substrates.
• the substrate or substrates can be organic, thermoplastic, thermosetting, metallic, ceramic, or other suitable inorganic material.
• the substrates can be multi-layered substrates such as substrates used in printed circuit boards in which improved adhesion is desired between the curable compositions and the substrate or substrates of the composite article.
• the composite articles can be made by bonding the curable composition to at least one surface of the substrate in the composite article. This can be carried out by curing the composition sufficiently to obtain adherence such that the curable composition and the substrate are bonded together securely to form the composite article.
• the cure temperature should range from -40 °C to 80 0 C, preferably from 0 0 C to 60 0 C, and more preferably from 15-35 0 C.
• the time for curing the composition on the substrate can range from 5 seconds to 24 hours, preferably from 30 seconds to 2 hours. This assures that the composition is sufficiently cured and fully adhered to the substrate.
• the curable composition can be applied to substrates by meter mixing, extruding, and/or the use of robotic or manual manipulation.
• Fully bonded composite articles can be made by disposing the curable composition to at least one surface of a polymeric substrate at a temperature less than the boiling point of water (i.e., 100 °C), and then concurrently curing the curable composition and bonding it to the polymeric substrate(s). This obviates the need to pre-dry the substrate(s). Composite articles can also be cured and bonded in a similar fashion at room temperature, thus eliminating the need of a curing oven. [0074] As noted above, the curable compositions can be easily packaged and delivered as multiple-component, multi-part adhesives.
• Combinations of components (i), (ii), and (iii) may be used as parts of multi-component, multi-part packages, provided components (ii) and (iii) are maintained separate from one another.
• a portion of (i) the free radical polymerizable monomer, oligomer or polymer, and (ii) the organosilicon functional boron amine catalyst complex can be packaged together in one part, while the remaining portion of (i) the free radical polymerizable monomer, oligomer or polymer, and (iii) the amine reactive compound, are packaged together in a second part.
• component (iii) can be delivered in the form of a filler treated with the amine reactive compound (iii), and packaged separately from (ii) the organosilicon functional boron amine catalyst complex.
• Components (i)-(iii) can also be stored together in 1-part formulations as long as oxygen is not present. [0075] In the embodiment where the amine-reactive compound (iii) is borne on a filler and all the components are combined into a single package, it is necessary to mix, package, and store components (i), (ii) and (iii), in a substantially oxygen free environment, to avoid premature thickening.
• filler that is inert with respect to amine compounds can be combined with (ii) the organosilicon functional boron amine catalyst complex, while the filler bearing amine reactive groups, can serve as component (iii), and packaged in a separate container from component (ii).
• component (i) can be included with either part of the formulation, or with both parts.
• the amine reactive compound can be introduced under conditions allowing it to be delivered in the gas phase to a pre-mixed mold filled with a composition containing components (i) and (ii). This allows extended working time, followed by rapid curing upon exposure to air.
• the curable composition When the curable composition is to be used as a foam, it is desirable to isolate the compound bearing active hydrogen, i.e., the blowing agent, the catalyst, and the component capable of generating a gas from one another.
• the judicious positioning of these three components in multi-part packages provides improved storage stability.
• Mixing and dispensing of multi-part packages can be performed in several ways. For example, the ingredients can be mixed at the desired volume ratio in air in a bag, or through a pressurized gun.
• the '512 patent describes several devices capable of mixing and dispensing two-part packages. It is also beneficial to tailor the viscosity and density of two- part packages to achieve efficient mixing and dispensing.
• Fillers of varying density and viscosity modifiers such as solvents, monomers, and polymers, can be used to impart control of these properties.
• the curable compositions of the invention are useful for preparing rubbers; tapes; adhesives; protective coatings; thin films; electronic components; photonic components; acoustic dampening components; thermoplastic and thermosetting monolithic molded parts such as toys or auto-body panels; sealants; foams; gaskets; seals; o-rings; connectors; and pressure sensitive adhesives.
• cured compositions may range in properties from compliant gels to rigid resins.
• Silicone elastomers and gels have numerous applications including their use as die attachment adhesives, lid sealants, encapsulants, gaskets, o-rings, potting compounds, and as conformal coatings. Silicone elastomers of the invention are capable of releasing from metal molds while at the same time adhering selectively to polymeric surfaces. Accordingly, the silicone elastomers can be co-molded or over-molded with polymeric resins in forming integrally bonded parts, such as connectors and housings for electrical wiring or electronic circuits, and diving masks for scuba diving. Silicone adhesives are useful for bonding electronic components to flexible or rigid substrates.
• an electrically conductive filler when used as an optional ingredient, it should be included in an amount sufficient to impart electrical conductivity to the curable composition.
• Curable compositions of this kind can be used for assembling electronic components, as substitutes for soldering, as electrical interface materials, and as conductive inks.
• the curable compositions can be delivered as rigid parts or flexible elastomers, and can be dispensed, pre- cured in rolls, or in sheet form as films, for application as pressure sensitive adhesives. They can also be dispensed and cured in place in some final applications.
• Foamed electrically conductive curable compositions can be used as gaskets and seals in applications such as in electrical and electronic housings, to prevent transmission of electromagnetic and radio frequency noise across sealed areas.
• thermally conductive filler When a thermally conductive filler is used as an optional ingredient, it should be included in an amount sufficient to impart thermal conductivity to the curable composition.
• Thermally conductive curable compositions are similarly useful for preparing thermally conductive rubbers, thermally conductive tapes, thermally conductive curable adhesives, thermally conductive foams, and thermally conductive pressure sensitive adhesives.
• the curable compositions are especially useful for preparing thermally conductive silicone adhesives.
• Thermally conductive silicone adhesives have numerous applications including their use as die attachment adhesives, solder replacements, and thermally conductive coatings and/or gaskets. Thermally conductive silicone adhesives are especially useful for bonding electronic components to flexible and/or rigid substrates.
• Thermally conductive curable compositions can also be used for assembling electronic components, as substitutes for soldering, as thermal interface materials, and as thermally conductive inks and/or greases.
• the curable compositions can be in the form of rigid parts or flexible elastomers, and can be pre-cured and dispensed in rolls or sheets as films, for application as pressure sensitive adhesives. They can also be dispensed wet and cured in place in final applications.
• Partially cured thermally conductive compositions can be used as thermally conductive greases.
• Foamed thermally conductive compositions can be used as gaskets and seals in electrical and electronic housings.
• the curable composition When used as a thermally conductive adhesive, the curable composition is particularly useful as a thermal interface material, in that it is capable of providing good bonding strength between heat sinks, heat spreaders, or heat dissipation devices, especially where the heat sink or heat dissipation device has a polymeric matrix.
• An organosilicon functional borane-amine catalyst complex was synthesized by the hydroboration of an allylsilane or a vinylsilane containing monomer, with BH3-THF
• the resulting hydroboration product was treated under a dry nitrogen purged atmosphere with 1.2 molar equivalents of 3- aminopropyltrimethoxysilane.
• the THF was removed under reduced pressure to obtain an air stable organosilicon functional borane-amine catalyst complex.
• the reaction equation is shown below wherein k is equal to three.
• Example Al The hydroboration product prepared in Example Al was treated under a dry nitrogen purged atmosphere with 0.3 molar equivalents of a 3-aminopropyldimethylsiloxy terminated polydimethylsiloxane (PDMS) oligomer.
• PDMS polydimethylsiloxane
• the oligomer had a number average molecular weight of 920 g/mol that provided a net amine:boron ratio of 0.6.
• THF was removed under reduced pressure to obtain an air stable organosilicon functional borane- amine catalyst complex.
• Example A3 Synthesis of a tris(trimethylsilylpropyl)borane aminosilane Catalyst Complex
• the hydroboration product prepared in Example Al was treated under a dry nitrogen purged atmosphere with 1.2 molar equivalents of a 3-aminopropyltriethoxysilane. THF was removed under reduced pressure to obtain an air stable organosilicon functional borane-amine catalyst complex.
• Cleaned substrates were placed in a machined aluminum support jig designed to support two three inch long substrate panels with an overlap area of one square inch, or 0.5 square inches, and a bond line thickness of 0.030 inches.
• the adhesive composition to be tested was applied to a first substrate with a microspatula.
• a second cleaned substrate was placed over the adhesive and compressed to form an appropriate thickness by lightly screwing down an upper restraining bar. Samples to be tested were allowed to cure at room temperature. After waiting between 14 and 16 hours, the test specimens were removed from the jigs, and all excess amounts of adhesive were trimmed away completely from the edges of the lap region with a razor blade.
• the samples were loaded into a MTS Sintech 5/G tensile tester available from the MTS Systems Corporation, Eden Prairie, Minnesota.
• the tensile tester was equipped with a 5000 pound force transducer and was tested at a crosshead speed of two inches per minute (in/min) (0.085 cm/second).
• Median values of maximum stress from at least three replicates of each substrate/composition combination were reported along with the mode of failure, rated by estimating the percentage of total bond area exhibiting cohesive failure (CF). If a fracture occurred through the silicone product that was very close to one of the substrate surfaces leaving only a thin film of residue, this effect was additionally noted as a thin film failure.
• Example C Measurement of Electrical Conductivity/Volume Resistivity
• the electrical conductivity reported in the Examples below was determined as a volume resistivity measurement, using the standard protocol described in US Patent 6,361,716 (March 26, 2002). Thus, the volume resistivity was determined using a Model 580 Micro ohm Meter of Keithley Instruments Incorporated, Cleveland, Ohio. The Meter was equipped with a four-point probe having spring loaded, gold plated, spherical tips. A test specimen was prepared by first placing two strips of Scotch brand tape 0.25 cm apart on a glass microscope slide, to form a channel extending along the length of the slide. An aliquot of the test curable composition was deposited at one end of the slide and over the channel.
• the curable composition to be analyzed was then spread over the entire channel by drawing a spatula through the curable composition and across the surface at an angle of approximately 45°.
• the test specimen was allowed to cure at room temperature overnight for about 16 hours.
• the voltage drop between the two inner probe tips was then measured at a selected current to provide a resistance value in ohms ( ⁇ ).
• V R(W x TfL)
• V the volume resistivity in ohm centimeters ( ⁇ -cm)
• R the resistance in ohms ( ⁇ ) of the cured composition measured between two inner probe tips spaced 2.54 centimeter apart
• W is the width of the cured layer in centimeters
• T is the thickness of the cured layer in centimeters
• L is the length of the cured layer between the inner probes in centimeters.
• the thickness of the cured layer was determined using an Ames Model LG 3500-0-04 thickness gauge made by Testing Machines Incorporated, Ronkonkoma, New York.
• Volume resistivity in ⁇ -cm units represents the average value of five measurements each performed on identically prepared test specimens. These measurements have a relative error of less than 10 percent.
• a Polymer Solution was prepared by diluting 13.5 parts by weight of poly(methylmethacrylate) (PMMA) having a weight average molecular weight of 350,000 g/mol, and 6.5 parts by weight of PMMA having a weight average molecular weight of
• a two part curable composition was then prepared by mixing as Part Al, 93 parts by weight of the Polymer Solution with 7 parts by weight of the organosilicon functional boron-amine catalyst complex of Example A3, in a Hauschild mixer for 10 seconds.
• Part Bl of the two part curable composition was prepared by mixing 90.9 parts by weight of the Polymer Solution with 9.1 parts by weight of acrylic acid, in a Hauschild mixer for 10 seconds. Equivalent weights of Parts Al and Bl were mixed together by hand kneading in a sealed polyethylene bag for about 20 seconds.
• the resulting mixture was dispensed onto three 3 inch x 1 inch x 0.125 inch substrates made of polyethylene terephthalate (PET).
• PET polyethylene terephthalate
• the substrates were reinforced with 30 weight percent of glass filler, and tested according to the method described in Example Bl.
• the adhesive joints all supported stresses in excess of 600 pounds per square inch (psi), with an average 670 ⁇ 20 psi, before being terminated by failure, i.e., breakage, of the PET substrate.
• psi pounds per square inch
• This example shows that the organosilicon functional borane amine catalyst of the invention can be used for curing organic free radical polymerizable compounds such as acrylic adhesives, in addition to organosilicon-based materials of subsequent examples; and that it is useful for curing acrylic type adhesives.
• the opacity of the cured material in Comparative Example 1 indicates that a typical organoborane amine complex catalyst yields an incompatible material.
• the transparency of the cured material in Example 2 indicates that the resulting material did not exhibit phase separation in bulk when an organosilicon functional boron amine catalyst complex of the invention was used.
• the size of these spherical microdomains ranged from 10-80 nanometer (nm) in diameter. Additionally, Comparative Example 1 exhibited larger, irregularly shaped heterogeneous methacrylate-rich particles ranging from 100-400 nm in size. Thus, the catalyst of the invention provides a more uniform phase behavior to the siloxane based curable compositions of the invention.
• a hydrosilylation curable adhesive composition was prepared by mixing together the following ingredients:
• (i) 28 parts by weight of an organopolysiloxane resin containing CH2 CH(CH3)2SiOi/2 units, (CH3)3SiOi/2 units, and Si ⁇ 4/2 units.
• the mole ratio of the CH2 CH(CH3)2SiOi/2 units and the (CH3)3SiOi/2 units combined to the Si ⁇ 4/2 units was 0.7.
• the resin had a weight average molecular weight of 22,000, a polydispersity of 5, and contained 1.8 percent by weight (5.5 mole percent) of vinyl groups.
• the adhesive composition was de-aired to remove any entrained air for 20 minutes at a reduced pressure of 2 mm of mercury.
• the adhesive composition was cast onto a 3 inch x 1 inch x 0.125 inch glass filled polybutylene terphthalate substrate, and cured for one hour on a hot plate having a linear thermal gradient ranging from about 90- 170 0 C over the length of the sample.
• the location at which the cured composition changed from a liquid to a non- flowable elastomeric solid was determined by probing the surface of the sample with a spatula, and then wiping away any uncured material. This position on the sample was correlated to a minimum cure temperature for a given heating time, using a linear regression analysis of the steady state temperature profile obtained from a thermocouples implanted in the hot plate surface at evenly spaced distances along the thermal gradient.
• a first Part A was prepared by combining (i) 42.8 parts by weight of a hydroxydimethylsilyl terminated PDMS having a number average molecular weight of 44,000 g/mol; (ii) 42.8 parts by weight of a methacryloxypropyldimethylsilyl terminated PDMS having a number average molecular weight of 13,000 g/mol; (iii) 5.0 parts by weight of an aminopropyldimethylsilyl terminated PDMS having a number average molecular weight of 920 g/mol; (iv) one part by weight of dibutyltindilaurate; and (v) 8.5 parts by weight of the organosilicon functional boron amine catalyst complex prepared in Example A2.
• a twelve second mixing cycle on a Hauschild mixer followed the addition of each of ingredients (i)-(v).
• a second Part B was prepared by combining (vi) 91.4 parts by weight of a methacryloxypropyldimethylsilyl terminated PDMS having a number average molecular weight of 13,000 g/mol; (vii) 3.2 parts by weight of isophoronediisocyanate; and (viii) 5.0 parts by weight of methacryloxypropyltrimethoxysilane.
• a twelve second mixing cycle on a Hauschild mixer followed the addition of each of ingredients (vi)-(viii).
• Parts A and B Two parts by weight of each of Parts A and B were then combined in a polyethylene bag and mixed by kneading the outside of the bag. Films approximately 0.03-0.04 inches thick were cast onto Mylar film substrates with a doctor blade and allowed to cure at room temperature (25 ⁇ 2 0 C). Curing was tested by probing the cured material of the film with a spatula until the material solidified. The ambient time to gelation was defined as the time needed for the material to cease being flowable at room temperature. The minimum cure temperature/time was defined as the time under ambient conditions at which the material was fully cured with no evidence of wetness at the surface or substrate interface.
• Table 1 shows that Comparative Example 2 requires heat curing of the platinum cured silicone elastomer, and that Comparative Example 3 is sensitive to cure inhibition by amine compounds.
• Table 1 shows that in Examples 3 and 4, the elastomeric silicone composition cured with the organosilicon functional boron amine catalyst complex of the invention at room temperature, and that it was not strongly inhibited by the presence of the same level of an amine compound.
• a two part siloxane resin composition was prepared by mixing in one container a , Part A' that contained (i) 47.6 parts by weight of a resin having a structure corresponding to MQ 3D(Ph)o.5T(methacryloxypropyl)o.2; and ( ⁇ ) 3.9 parts by weight of a catalyst containing tri-n-butyl borane complexed with 0.6 molar equivalents of a 3-aminopropyldimethylsiloxy- terminated polydimethylsiloxane oligomer.
• the oligomer had a number average molecular weight of 920 g/mol, and a number average molecular weight of 745 g/mol.
• Part B' was prepared by mixing (iii) 47.6 parts by weight of the same resin used in Part A', and (iv) 0.82 parts by weight of isophorone diisocyanate.
• the ingredients in each of Part A 1 and Part B' were mixed for 10 seconds in a Hauschild mixer.
• Equal weights of Part A' and Part B' were then mixed together in a polypropylene mixing cup for 10 seconds in a Hauschild mixer.
• the composition gelled within 50 seconds and yielded a hard solid that had a cloudy appearance.
• Example 5 To 11.7 parts by weight of a methacryloxypropyl dimethylsilyl terminated polydimethylsiloxane having a number average molecular weight (M n ) of about 13,000, was added 82.9 parts by weight of a fatty acid lubricated silver flake filler (RA- 127) from American Chemet Corporation, Chicago, Illinois. The two materials were mixed in a Hauschild mixer for 24 seconds. 5.4 parts by weight of the organosilicon functional boron amine catalyst complex prepared in Example Al was added to the mixture. The headspace of the mixing cup was purged with nitrogen gas and then mixed for two 24 second mixing cycles. Upon exposing the sample to ambient air, the material crosslmked and became non- flowable within 5 minutes.
• M n number average molecular weight
• the cured material was found to have a volume resistivity of 7.7 E-03 ⁇ 0.6 E-03 ⁇ -cm when tested 24 hours after casting the sample.
• the organosilicon functional boron amine catalyst complexes of the invention can be seen as being useful as catalysts in the preparation of conductive materials such as electrically conductive siloxanes.
• a two part siloxane resin composition was prepared in the same manner as in
• Comparative Example 4 except that 3.4 parts by weight of the oraganosilicon functional boron amine catalyst complex of Example A2 was substituted for the catalyst used in Part A'.
• the composition gelled within 20 seconds and formed a hard solid that was transparent.
• This example shows that the organosilicon functional boron amine catalyst complexes of the invention are useful as catalysts for curing organopolysiloxane resins.
• the improved transparency of the cured product of Example 6 shows that the organosilicon functional boron amine catalyst complexes of the invention are capable of reducing phase separation in organopolysiloxane resin matrices.

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