Moisture-curable network silicone polymers and uses thereof

Abstract

The present invention provides moisture-curable network silicone polymers and compositions thereof that have improved resistance to automotive oils at high temperatures. The network silicone polymers contain terminal moisture-curable functional groups and partially crosslinked structures containing CCC bonds that separate the siloxane backbone from the moisture-curable functional groups and prevent thermal decomposition of the siloxane backbone.

Description

[Technical Field]

[0001] The present invention relates to moisture-curable network silicone polymers and compositions thereof that provide resistance to oil and heat at high temperatures and are particularly suitable as silicone room-temperature vulcanizing sealants and adhesives for automotive gaskets. [Background technology]

[0002] Curable silicone polymers and compositions are useful as adhesives, sealants, release coatings, conformal coatings, potting compounds, encapsulants, etc. in a wide range of applications, including automotive, construction, highway, electronic equipment and packaging assemblies, electrical appliance assemblies, and consumer applications. Typically, the curable silicone polymers and compositions used in these applications are tailored to provide strength, toughness, cure speed, modulus, elongation, and resistance to high temperatures and humidity. For example, curable silicone polymers and compositions can be formed into gaskets, which are widely used in the automotive industry. During use, silicone compositions are exposed to various conditions and must continue to function without losing their integrity. One such condition is exposure to engine oil at high temperatures.

[0003] Oil-resistant silicone compositions used as room-temperature vulcanizing (RTV) sealants are described in U.S. Patent Nos. 5,419,096, 4,514,529, 4,673,750, 4,735,979, and 4,847,396, as well as International Publication No. WO 9319130. One drawback of RTV silicone compositions is their slow cure rate, which makes them commercially unacceptable for certain applications, such as sealing electronic modules, where mass production may depend on cure rate. Therefore, silicone compositions with improved cure rates are desirable. Also, as described in European Patent Publication No. 0572148 and U.S. Patent Nos. 5,082,886 and 4,052,357, certain grades of metal oxides and / or fiberized blast furnace slag fibers have been added to silicone compositions to impart oil resistance to elastomer products. However, these additions complicate the process and increase costs.

[0004] While many in the art provide solutions for silicone polymers and compositions, moisture-curable silicone polymers have poor resistance to petroleum oil at high temperatures due to a phenomenon known in the art as "end-group backbiting," "backbiting," or "unzipping" reactions. Little has been done to improve the oil resistance of silicone polymers by modifying their "end-group structure." Therefore, there is a need in the art for silicone polymers that undergo efficient moisture curing, do not form corrosive acid by-products, and at the same time provide oil resistance at high temperatures, avoid the use of exhausted fillers, and prevent degradation of the inherent silicone backbone due to backbiting reactions. The present invention meets this need. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 5,419,096 [Patent Document 2] U.S. Patent No. 4,514,529 [Patent Document 3] U.S. Patent No. 4,673,750 [Patent Document 4] U.S. Patent No. 4,735,979 [Patent Document 5] U.S. Patent No. 4,847,396 [Patent Document 6] International Publication No. WO9319130 [Patent Document 7] European Patent Publication No. 0572148 [Patent Document 8] U.S. Patent No. 5,082,886 [Patent Document 9] U.S. Patent No. 4,052,357 Summary of the Invention [Means for solving the problem]

[0006] The present invention provides moisture-curable network silicone polymers and compositions thereof for sealing and bonding flanges in automotive powertrains and heating, ventilation, and air conditioning (HVAC). During use, the cured silicone compositions of the present invention can be exposed to a variety of conditions, including high temperatures, automotive oils, and acids, and continue to function without loss of integrity. One such condition is exposure to engine oil at high temperatures.

[0007] One aspect of the present invention is a method for producing a medicament for the treatment of a pulmonary arthritis. (i) from about 10 to about 98% vinyl-terminated polyorganosiloxanes having a weight average molecular weight greater than about 1,000 g / mol, preferably greater than about 10,000 g / mol; (ii) from about 1 to about 20% of hydride-terminated polyorganosiloxanes having a weight average molecular weight of less than about 100,000 g / mol, preferably less than about 10,000 g / mol; (iii) from about 0.001 to about 20% of a vinyl or hydride (SiH) polyfunctional organic compound, and (iv) from about 0.00001 to about 5% of a hydrosilylation catalyst; A network silicone polymer prepared by the molar ratio of vinyl functional groups to hydride functional groups is about 0.1 to 0.8; The weight average molecular weight of the silicone polymer is about 10,000 to 3,000,000 g / mol, and the silicone polymer is a network silicone polymer.

[0008] Another aspect of the present invention is a method for producing a silicone polymer comprising the above-described (A) silicone polymer having excess hydride functionality and (B) an end-capped vinyl-functional silane CH═CH—SiY. n R 3-n wherein Y is alkoxy, aryloxy, acetoxy, oximino, enoxy, amino, α-hydroxycarboxylic acid amide (-OCR'CONR"), α-hydroxycarboxylic acid ester (-OCR'COOR"), H, OH, halogen, or a combination thereof; n=1, 2, or 3; each R, R', and R" is independently alkyl, aryl, fluoroalkyl, trialkylsilyl, triarylsilyl, or a combination thereof; and the ratio of vinyl functional groups of (B) the end-capped vinyl-functional silane to free hydride functional groups of (A) the silicone polymer is about 1 to 1.5.

[0009] Another aspect of the present invention relates to a moisture-curing composition comprising: (1) about 10 to about 90% of the moisture-curable silicone polymer described above; (2) about 0.00001 to about 5% of a moisture-cure catalyst, and (3) Optionally, about 5 to about 90% finely divided inorganic filler or mixture of fillers. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 shows the viscosity curves for Comparative Example 2 (triangle points) and Example 6 (square points). [Figure 2] FIG. 2 shows GPC chromatograms of Comparative Example 2 (straight line) and Example 6 (dotted line). DETAILED DESCRIPTION OF THE INVENTION

[0011] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In the case of conflict, the present specification, including definitions, will control. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosure, preferred methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. The materials, methods, and examples disclosed herein are illustrative only and are not intended to be limiting.

[0012] As used herein, the term "comprise" may encompass the embodiments "consisting of" and "consisting essentially of." As used herein, the terms "comprise(s)," "include(s)," "having," "has," "can," "contain(s)," and variations thereof, are intended to be open-ended transitional phrases, terms, or words that require the presence of the specified ingredients / steps and allow for the presence of other ingredients / steps. However, such descriptions should be interpreted as causing the composition or method to "consist of" and "consist essentially of" the listed ingredients / steps, thereby allowing for the presence of only the specified ingredients / steps and possible impurities resulting therefrom, and excluding other ingredients / steps.

[0013] Numerical values herein, particularly as they relate to polymers or polymer compositions, reflect average values for compositions that may contain individual polymers of differing properties. Furthermore, unless indicated to the contrary, numerical values should be understood to encompass the same numerical value when reduced to the same number of significant figures, and numerical values that differ from the stated value by no more than the experimental error of conventional measuring techniques of the type described herein to determine the value.

[0014] All ranges disclosed herein are inclusive of the recited endpoints and are independently combinable (e.g., the range "2 to 10" includes the endpoints 2 and 10, and all intermediate values). The endpoints of ranges and values disclosed herein are not limited to the exact ranges or values. They are sufficiently imprecise to encompass values that approximate those ranges and / or values. As used herein, approximation language may be applied to modify quantitative expressions that may vary without altering the associated basic function. Thus, values modified by one or more terms, such as "about," may not be limited to the exact value specified. In at least some instances, approximation language may correspond to the precision of an instrument for measuring a value. The modifier "about" should also be considered to disclose a range defined by the absolute values of the two endpoints. For example, the expression "about 2 to about 4" also discloses the range "2 to 4." The term "about" may refer to plus or minus 10% of the indicated number. For example, "about 10%" may indicate a range of 9% to 11%, and "about 1" may mean 0.9 to 1.1. Other meanings of "about" may be apparent from the context, such as rounding, e.g., "about 1" may mean 0.5 to 1.4.

[0015] As used herein, a polymer or oligomer is a macromolecule made up of about one or more monomeric units. The terms "polymer" and "oligomer," or "polymeric" and "oligomeric," are used interchangeably herein.

[0016] As used herein, the term "alkyl" refers to a linear, cyclic, or branched moiety containing C1-C24 carbons and containing only single bonds between carbon atoms in the moiety, such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, heptyl, 2,4,4-trimethylpentyl, 2-ethylhexyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-hexadecyl, and n-octadecyl.

[0017] As used herein, the term "aryl" refers to a monovalent unsaturated aromatic carbocyclic group of 6 to 24 carbon atoms having a single ring (e.g., phenyl) or multiple condensed rings, in which at least one ring is aromatic (e.g., naphthyl, dihydrophenanthrenyl, fluorenyl, or anthryl). Preferred examples include phenyl, methylphenyl, ethylphenyl, methylnaphthyl, ethylnaphthyl, and the like.

[0018] As used herein, the term "alkoxy" refers to the group --OR, where R is alkyl as defined above.

[0019] As used herein, the above groups may be further substituted or unsubstituted. When substituted, the hydrogen atoms on the group can be independently selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl, heteroalicyclyl, aralkyl, heteroaralkyl, (heteroalicyclyl)alkyl, hydroxy, protected hydroxyl, alkoxy, aryloxy, acyl, ester, mercapto, alkylthio, arylthio, cyano, halogen, carbonyl, thiocarbonyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N- Substituted with one or more substituents selected from thiocarbamyl, C-amido, N-amido, s-sulfonamido, N-sulfonamido, C-carboxy, protected C-carboxy, O-carboxy, isocyanate, thiocyanate, isothiocyanate, nitro, silyl, sulfenyl, sulfinyl, sulfonyl, haloalkyl, haloalkoxy, trihalomethanesulfonyl, trihalomethanesulfonamido, amino, including mono- and di-substituted amino groups, and protected derivatives thereof. When aryl is substituted, the substituents on the aryl group may form a non-aromatic ring fused to the aryl group, including cycloalkyl, cycloalkenyl, cycloalkynyl, and heterocyclyl.

[0020] As used herein, the term "moisture cure" refers to the curing or vulcanization of the curable portion of a material or polymer by a condensation cross-linking reaction of the terminal functional groups of the polymer chains brought about by water or moisture in the air in the presence of a moisture-cure catalyst.

[0021] As used herein, the term "silicone polymer" refers to a siloxane polymer, a polyorganosiloxane, or a polydiorganosiloxane such as polydimethylsiloxane (PDMS).

[0022] The present invention provides the art with a new class of network silicone polymers containing CCC linkages in the backbone and at branch or crosslink points of the backbone. Network silicone polymers containing CCC linkages offer improved protection from backbiting and unzipping reactions. The network silicone polymers can be end-capped with functional groups that can undergo further moisture cure.

[0023] Silanol- and / or alkoxysilyl-terminated silicone polymers undergo moisture cure in air in the presence of a moisture cure catalyst. They are widely used as insealants and adhesives. However, silanol- or alkoxy-terminated silicone polymers readily decompose and depolymerize in oil at high temperatures through an "unzipping" or "chain backbiting" and chain "scissoring" mechanism, as reported in Polymer Degradation and Stability 94 (2009) pp. 465-495. When silanol- and / or alkoxysilyl-terminated silicone polymers are heated, their viscosity and molecular weight initially increase rapidly, which is typical of intermolecular reactions between polymer chain ends via silanol condensation reactions. With prolonged high-temperature conditions, the molecular weight of the polymer decreases due to "backbiting," in which the silanol functions promote intramolecular redistribution reactions, resulting in the production of low-molecular-weight cyclic siloxanes. This decomposition process is usually exacerbated in the presence of acids or bases typically present in aged oils. Volatile cyclic trimers and tetramers are the most prominent products of this fragmentation and depolymerization due to their kinetic and thermodynamic stability at the decomposition temperature. Their evaporation adds an additional driving force to the degradation process. The decrease in molar mass is found to be proportional to the degree of volatilization, confirming the stepwise nature of volatile formation characteristic of unzipping reactions. Therefore, PDMS depolymerization is primarily governed by molecular structure and kinetic considerations, rather than bond energy. The formation of the intramolecular cyclic transition state is the rate-determining step. Without being bound by any particular theory, it is hypothesized that silicon d-orbital participation is responsible for the rearrangement of siloxane bonds, leading to the removal of cyclic oligomers and chain shortening.

[0024] Linear carbon-carbon-carbon (CCC) spacers within the silicone polymer backbone can be easily achieved by hydrosilylation of vinyl or allyl functional groups from either the silicone or organic component with Si-H functional groups on the silicone component. This CCC spacer within the silicone polymer provides rigidity to the flexible silicone polymer backbone, preventing degradation of the silicone polymer by backbiting or chain scissoring mechanisms. Furthermore, the CC spacer influences the thermal stability of the silicone polymer. Other useful rigid spacers in silicone polymers include cyclic or branched links containing divalent alkylene, arylene, oxyalkylene, oxyarylene, siloxane-alkylene, siloxane-arylene, ester, amine, glycol, imide, amide, alcohol, carbonate, urethane, urea, sulfide, ether, or derivatives or combinations thereof. A simple method for introducing rigid spacers such as cyclic alkyls is by hydrosilylation of multiple vinyl-functional organic compounds, such as TVCH, with Si-H-containing silicone polymers.

[0025] The silicone polymers of the present invention, with their 3D network structure containing CCC bonds, are not only more resistant to degradation than linear silicone polymers via chain backbiting or chain scissoring mechanisms, but also have excellent thermal stability. In particular, the polymers exhibit improved oil resistance at 150°C for over 1000 hours. The network structure also provides early green strength for sealant and adhesive applications. Typically, moisture curing processes are slow, requiring hours to days to achieve full adhesive strength. Therefore, carefully designed network silicone polymers offer excellent early strength for a variety of applications.

[0026] One aspect of the present invention relates to a silicone polymer prepared from: (i) from about 10 to about 98% vinyl-terminated polyorganosiloxanes having a weight average molecular weight greater than about 1,000 g / mol, preferably greater than about 10,000 g / mol; (ii) from about 1 to about 20% of hydride-terminated polyorganosiloxanes having a weight average molecular weight of less than about 100,000 g / mol, preferably less than about 10,000 g / mol; (iii) from about 0.001 to about 20% of a vinyl or hydride (SiH) polyfunctional organic compound, and (iv) from about 0.00001 to about 5% of a hydrosilylation catalyst; the molar ratio of vinyl functional groups to hydride functional groups is about 0.1 to 0.8; The weight average molecular weight of the network silicone polymer is about 10,000 to 3,000,000 g / mol, preferably about 100,000 to 500,000 g / mol.

[0027] The vinyl-terminated polyorganosiloxane polymer has α,ω-end-capped vinyl groups. The polyorganosiloxane polymer has at least two or more (R'R"SiO) units, where R' and R" are independently alkyl, aryl, fluoroalkyl, trialkylsilyl, triarylsilyl, vinyl, or combinations thereof. Examples of polyorganosiloxane polymers are polydialkylsiloxanes, polydiarylsiloxanes, and polyalkylarylsiloxanes. In a preferred embodiment, the polyorganosiloxane polymer is a polymer or copolymer of polydimethylsiloxane, polydiphenylsiloxane, polymethylphenylsiloxane, poly(3,3,3-trifluoropropylmethyl)siloxane, or mixtures thereof. In a most preferred embodiment, the polyorganosiloxane polymer is vinyl-terminated polydimethylsiloxane (PDMS). The vinyl-terminated polyorganosiloxane polymer has a weight average molecular weight (Mw) greater than about 1,000 g / mol, preferably greater than about 10,000 g / mol.

[0028] In one embodiment of the present invention, two distinct, separate vinyl-terminated siloxane polymers are used to form a silicone polymer product. The first vinyl-terminated siloxane polymer is a high molecular weight siloxane polymer having a weight average molecular weight (Mw) greater than 100,000 g / mol, preferably from about 120,000 to about 10,000,000 g / mol. The high molecular weight siloxane polymer provides cohesion, adhesion, and elongation. The second vinyl-terminated siloxane polymer is a low molecular weight polymer having a weight average molecular weight (Mw) less than 100,000 g / mol, preferably from about 5,000 to about 70,000 g / mol. The second vinyl-terminated siloxane polymer provides tunable crosslink density and viscosity of the adhesive. The high and low molecular weight reactive siloxane polymers are used together to adjust the crosslink density, modulus, and viscosity of the silicone polymer and composition.

[0029] The hydride-terminated polyorganosiloxane polymer has α,ω-end-capped H groups. The polyorganosiloxane polymer has at least two or more (R'R"SiO) units, where R' and R" are independently alkyl, aryl, fluoroalkyl, trialkylsilyl, triarylsilyl, vinyl, or combinations thereof. Examples of polyorganosiloxane polymers are polydialkylsiloxanes, polydiarylsiloxanes, and polyalkylarylsiloxanes. In a preferred embodiment, the polyorganosiloxane polymer is a polymer or copolymer of polydimethylsiloxane, polydiphenylsiloxane, polymethylphenylsiloxane, poly(3,3,3-trifluoropropylmethyl)siloxane, or mixtures thereof. In a most preferred embodiment, the polyorganosiloxane polymer is H-terminated polydimethylsiloxane (PDMS).

[0030] The hydride-terminated siloxane polymer has a weight average molecular weight of less than about 100,000 g / mol, preferably less than about 50,000 g / mol, and more preferably less than 10,000 g / mol.

[0031] Vinyl or hydride (SiH) polyfunctional organic compounds used to make network silicone polymers, or organic compounds containing vinyl polyfunctional organic compounds, or compounds of the formula (R3R4SiO) n In the formula, R3 is vinyl, allyl, H, or a combination thereof, R4 is R3, alkyl, aryl, fluoroalkyl, trialkylsilyl, or triarylsilyl, or a combination thereof, and n=3 to 20. Examples of organic compounds containing vinyl or allyl polyfunctional organic compounds are 1,2,4-trivinylcyclohexane, triallyloxytriazine, triallylbenzenetricarboxylate, tetravinylsilane, trivinylmethylsilane, tetravinylsilane, trivinylethoxysilane, and tris(trimethyl)silane. Polyfunctional vinyl or allyl groups of the formula (R3R4SiO) n Examples of SiH-containing cyclic or linear siloxanes containing 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane, 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane, tetravinyldimethyldisiloxane, 1,3,5-11,2,5 ...tetravinyldimethyldisiloxane, tetravinyldimethyldisiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravinyldimethylsiloxane, tetravin ,5; tris(vinyldimethylsiloxy)methylsilane, 1,3,5,7-tetramethylcyclotetrasiloxane, 1,3,5-trimethylcyclotrisiloxane, 1,3,5-trivinyl-1,1,3,5,5-pentamethyltrisiloxane, vinylmethylsiloxane homopolymer, vinylmethylsiloxane-dimethylsiloxane copolymer, methylhydrosiloxane homopolymer, methylhydrosiloxane-dimethylsiloxane copolymer, vinyl Q resin, vinyl T resin, hydride Q resin, and hydride T resin.

[0032] The molar ratio of vinyl functional groups to hydride functional groups is defined as follows:

[0033]

number

[0034] Therefore, there is an excess of hydride functionality in the silicone polymer.

[0035] The silicone polymer is typically formed neat in the presence of a suitable hydrosilylation catalyst. No organic solvent is required. In one embodiment, the silicone polymer is prepared by reacting all of the components at a reaction temperature of about 25-150°C for about 1-24 hours.

[0036] The hydrosilylation catalysts of the present invention are transition metal complexes of Pt, Rh, or Ru. Preferred catalysts are Speer's catalyst HPtCl, or Karstedt's catalyst, or any alkene-stabilized platinum(0). The utility of non-transition metal catalysts, including early main group metals, borane and phosphonium salts, and N-heterocyclic carbenes, has also been disclosed.

[0037] Another aspect of the present invention is a method for producing a silicone polymer comprising the above-described (A) silicone polymer having excess hydride functionality and (B) an end-capped vinyl-functional silane CH═CH—SiY. n R 3-n wherein Y is alkoxy, aryloxy, acetoxy, oximino, enoxy, amino, α-hydroxycarboxylic acid amide (-OCR'CONR"), α-hydroxycarboxylic acid ester (-OCR'COOR"), H, OH, halogen, or a combination thereof; n=1, 2, or 3; each R, R', and R" is independently alkyl, aryl, fluoroalkyl, trialkylsilyl, triarylsilyl, or a combination thereof; and the ratio of vinyl functional groups of (B) the end-capped vinyl-functional silane to free hydride functional groups of (A) the silicone polymer is about 1 to 1.5.

[0038] The end-capped vinyl-functional silanes used to make moisture-curable silicone polymers have the formula CH2=CH-SiY n R 3-n wherein R is independently alkyl, aryl, fluoroalkyl, trialkylsilyl, triarylsilyl, or a combination thereof; Y is alkoxy, aryloxy, acetoxy, oximino, enoxy, amino, amide, lactamide, lactate ester, ester, or halogen; and n is 1 to 3. n SiR 3-n Examples of silanes are vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinyltriethoxysilane, etc. Vinyl-SiY n SiR 3-n will typically be used in an amount of 0.01 to 30%, more preferably 0.1 to 20% by weight of the silicone polymer.

[0039] The molar ratio of vinyl functional groups to hydride functional groups is defined as follows:

[0040]

number

[0041] Useful moisture-cure moieties of silicone polymers typically include silyl groups containing alkoxy, aryloxy, acetoxy, oximino, enoxy, amino, lactate amide, lactate ester, H, or halogen substituents, as is well known to those skilled in the art.

[0042] Moisture-curable silicone polymers are typically formed neat, without the need for organic solvents. The network silicone polymer is first prepared as described above with about 0.1 to about 10% of a vinyl-functional silane, CH2=CH-SiY. n R 3-n An additional about 0.00001 to about 5% of a hydrosilylation catalyst is added, and the reaction is continued at about 25 to 150° C. for an additional 1 to 24 hours.

[0043] Yet another aspect of the present invention relates to a moisture-curing composition comprising: (1) about 10 to about 90% of the moisture-curable silicone polymer described above; (2) about 0.00001 to about 5% of a moisture-cure catalyst, and (3) Optionally, about 5 to about 90% finely divided inorganic filler or mixture of fillers.

[0044] The moisture-curing catalyst used in the moisture-curable silicone composition of the present invention includes those known to those skilled in the art to be useful in catalyzing and accelerating moisture curing. The catalyst can be a metal catalyst or a non-metal catalyst. Examples of metal catalysts useful in the present invention include organometallic compounds of tin, titanium, zinc, zirconium, lead, iron, cobalt, antimony, manganese, and bismuth. Examples of non-metal catalysts include amines, amidines, and tetramethylguanidine.

[0045] In one embodiment, moisture cure catalysts useful for accelerating the moisture cure of silicone compositions include dibutyltin dilaurate, dimethyl dineodecanoate tin, dioctyltin didecyl mercaptide, bis(neodecanoyloxy)dioctylstannane, dimethyl bis(oleoyloxy)stannane, dibutyltin diacetate, dibutyltin dimethoxide, stannous octanoate, isobutyltin triceroate, dibutyltin oxide, solubilized dibutyltin oxide, dibutyltin bisdiisooctyl phthalate, bis-tripoxysilyldioctyltin, dibutyltin bis The tin ester may be selected from, but is not limited to, d-acetylacetone, silylated dibutyltin dioxide, carbomethoxyphenyltin tris-uberate, isobutyltin triceroate, dimethyltin dibutyrate, dimethyltin di-neodecanoate, triethyltin tartrate, dibutyltin dibenzoate, tin oleate, tin naphthenate, butyltin tri-2-ethylhexylhexoate, tin butyrate, d-ioctyltin d-idecyl mercaptide, bis(neodecanoyloxy)d-ioctylstannane, or dimethylbis(oleoyloxy)stannane. In one preferred embodiment, the moisture-cure catalyst is selected from the group consisting of dimethyl dineodecanoate tin (available from Momentive Performance Materials, Inc. under the tradename FOMREZ UL-28), dioctyltin didecyl mercaptide (available from Momentive Performance Materials, Inc. under the tradename FOMREZ UL-32), bis(neodecanoyloxy)dioctylstannane (available from Momentive Performance Materials, Inc. under the tradename FOMREZ UL-38), dimethyl bis(oleoyloxy)stannane (available from Momentive Performance Materials, Inc. under the tradename FOMREZ UL-50), and combinations thereof. More preferably, the moisture-cure catalyst is dimethyl dineodecanoate tin. In the moisture-cure composition according to the present invention, the moisture-cure catalyst is present in an amount of 0.1 to 5 wt. %, based on the total weight of the composition.

[0046] However, environmental regulatory agencies and directives have tightened or are expected to tighten restrictions on the use of organotin compounds in formulated products. For example, compositions containing more than 0.5% by weight of dibutyltin are currently required to be labeled as toxic under the Reproductive IB classification. Dibutyltin-containing compositions are proposed to be completely phased out from consumer applications over the next 3 to 5 years. The use of alternative organotin compounds, such as dioctyltin and dimethyltin compounds, can only be considered as a short-term remediation plan, as these organotin compounds may also be restricted in the future. Identifying non-tin compounds that accelerate the condensation cure of moisture-curing silicone compositions would be beneficial. Examples of non-toxic alternatives to organotin catalysts include titanium isopropoxide, zirconium octanoate, iron octanoate, zinc octanoate, cobalt naphthenate, tetrapropyl titanate, tetrabutyl titanate, titanium di-n-butoxide bis(2,4-pentanedionate), titanium diisopropoxide bis(2,4-pentanedionate), and the like. Other non-toxic alternatives to organotin catalysts are based on amino acid compounds. An example of an amino acid catalyst is an N-substituted amino acid, in which the amino acid compound contains at least one group other than hydrogen attached to the N-terminus. In another embodiment, the present invention may encompass a curable composition using an amino acid compound as a condensation accelerator, in which the amino acid compound is an O-substituted amino acid, in which the O-terminus contains a group other than hydrogen attached to the O-terminus. Other suitable amine catalysts include, for example, amino-functional silanes. The non-toxic moisture cure catalyst is used in an amount sufficient to effect moisture cure, which is generally from about 0.05% to about 5.0% by weight, advantageously from about 0.5% to about 2.5% by weight.

[0047] The fillers useful in the present invention are finely divided inorganic fillers. By "finely divided," we mean that the filler has an average particle size of less than about 5 microns. Advantageously, the inorganic filler has an average particle diameter of about 0.2 to about 2.0 microns. In particularly advantageous embodiments, i) at least about 90% of the inorganic fillers have a diameter of less than 2 microns, and ii) at least about 65% of the inorganic fillers have a diameter of less than 1 micron. The filler may be present in an amount of at least about 15% by weight of the total composition. Desirably, the filler is present in an amount of about 25% to about 80% by weight, more desirably, about 25% to about 60% by weight of the total composition.

[0048] The silicone composition of the present invention includes specific fillers to help impart oil resistance to the final cured composition. Because the fillers are basic in nature, they can react with any acidic by-products formed in the working environment in which the composition of the present invention is intended to be used. By doing so, the fillers neutralize the acidic by-products before they can degrade the elastomer, thereby improving bond retention. These fillers include, for example, lithopone, zirconium silicate, diatomaceous earth, calcium clay, hydroxides such as calcium hydroxide, aluminum hydroxide, magnesium hydroxide, and iron hydroxide; carbonates such as sodium carbonate, potassium carbonate, calcium carbonate, and magnesium carbonate; metal oxides such as zinc, magnesium, chromium, zirconium, aluminum, titanium, and iron oxide, and mixtures thereof. The filler may be present in the curable composition at any suitable concentration.

[0049] A preferred filler is calcium carbonate. A commercially available example of a calcium carbonate filler suitable for use in the present invention is sold by Omya Corporation under the trade name OMYACARB® UF-FL. Any commercially available precipitated calcium carbonate can be used in the present invention. The precipitated calcium carbonate should be present, for example, in an amount of about 5 to about 50% by weight of the total composition. Desirably, the calcium carbonate is present in an amount of about 5 to about 15% by weight.

[0050] The present compositions may also include magnesium oxide particles, a basic filler component, along with precipitated calcium carbonate. Desirably, the magnesium oxide is present in an amount of about 5 to about 50% by weight, e.g., about 10 to about 25% by weight, of the total composition. Any magnesium oxide satisfying the above physical characteristics may be used in accordance with the present invention. Desirably, the magnesium oxides of the present invention are Magchem 50M and Magchem 200-AD, commercially available from Martin Marietta Magnesia Specialties, Inc., Baltimore, Maryland. These commercially available fillers contain about 90% or more by weight of magnesium oxide particles, along with various other oxides, including, for example, calcium oxide, silicon dioxide, iron oxide, aluminum oxide, and sulfur trioxide.

[0051] Another desirable type of filler is reinforcing silica. The silica may be fumed silica, which may be untreated or treated with an adjuvant to render it hydrophobic. Fumed silica should be present at a level of at least about 5% by weight of the composition to achieve substantial reinforcing effect. While the optimum silica level varies depending on the characteristics of the specific silica, it has generally been observed that the thixotropic effect of silica can produce impractically high viscosities of the composition before the maximum reinforcing effect is reached. Hydrophobic silicas tend to have a lower thixotropic effect, allowing for higher amounts to be included in compositions with the desired consistency. Therefore, when selecting the silica level, a balance must be struck between the desired reinforcing and the actual viscosity. Fumed silica treated with hexamethyldisilazane (HDK2000 by Wacker Chemie, Burghausen, Germany) is particularly desirable. A commercially available example of fumed silica suitable for use in the present invention is sold by Degussa under the trade name Aerosil R8200.

[0052] A thixotropic agent may be desirable to modify the dispensing characteristics of the composition by adjusting the viscosity. Thixotropic agents are used in amounts ranging from about 0.05 to about 25% by weight of the total composition. As previously mentioned, common examples of such thixotropic agents include fumed silica, which may be untreated or may be treated to alter their surface chemistry. Virtually any reinforced fumed silica may be used. Examples of such treated fumed silica include polydimethylsiloxane-treated silica and hexamethyldisilazane-treated silica. Such treated silicas are commercially available from Cabot Corporation, for example, under the trade names Cabosil ND-TS and Evonik Aerosil, such as Aerosil R805. Among untreated silicas, amorphous and hydrated silicas may be used. For example, commercially available amorphous silicas include Aerosil 300, which has an average primary particle size of about 7 nm, Aerosil 200, which has an average primary particle size of about 12 nm, and Aerosil 130, which has an average primary particle size of about 16 nm; commercially available hydrous silicas include Nipsil E150, which has an average particle size of 4.5 nm, Nipsil E200A, which has an average particle size of 2.0 nm, and Nipsil E220A (manufactured by Nippon Silica Kogyo Co., Ltd.), which has an average particle size of 1.0 nm. Other desirable fillers for use as thixotropic agents include those composed of or containing aluminum oxide, silicon nitride, aluminum nitride, and silica-coated aluminum nitride. Hydroxyl-functional alcohols are also suitable as thixotropic agents, such as tris[copoly(oxypropylene)(oxypropylene)] ether of trimethylolpropane and polyalkylene glycols commercially available from BASF under the trade name Pluracol V-10.

[0053] Other conventional fillers may also be incorporated into the present compositions, provided they impart basicity to the composition and do not adversely affect the oil-resistant cure mechanism and adhesive properties of the final product produced therefrom. Generally, any suitable mineral, carbonaceous, glass, or ceramic filler may be used, including, but not limited to, precipitated silica, clay, metal salts of sulfates, chalk, lime powder, precipitated and / or pyrogenic silicic acid, phosphates, carbon black, quartz, zirconium silicate, gypsum, silicon nitride, boron nitride, zeolite, glass, plastic powders, graphite, synthetic fibers, and mixtures thereof. Fillers may be used in amounts ranging from about 5 to 70 weight percent of the total composition. A commercially available example of a precipitated silica filler suitable for use herein is sold under the trade name Zeotix 95 by J.M. Huber.

[0054] Organic fillers, especially silicone resins, wood fibers, wood flour, sawdust, cellulose, cotton, pulp, cotton, wood chips, chopped straw, and rice husks can also be used. Additionally, short fibers such as glass fibers, glass filaments, polyacrylonitrile, carbon fibers, Kevlar fibers, or polyethylene fibers can also be added.

[0055] The silicone composition can optionally further comprise a silane adhesion promoter, a functional polymer and / or an oligomeric adhesion promoter. The adhesion promoter may act to enhance the adhesive properties of the curable silicone composition to certain substrates (i.e., metal, glass, plastic, ceramic, and blends thereof). Any suitable adhesion promoter may be used for this purpose, depending on the particular substrate elements used in a given application. Examples of useful silane adhesion promoters include C3-C24 alkyltrialkoxysilane, (meth)acryloxypropyltrialkoxysilane, chloropropylmethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrismethoxyethoxysilane, vinylbenzylpropylmethoxysilane, aminopropyltrimethoxysilane, vinylacetoxysilane, glycidoxypropyltrialkoxysilane, beta-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, mercaptopropylmethoxysilane, 3-aminopropyltriethoxysilane, aminomethyltrimethoxysilane, aminomethyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, (N-2-aminoethyl)-3-aminopropyltrimethoxysilane, Sisilane, (N-2-aminoethyl)-3-aminopropyltriethoxysilane, diethylenetriaminopropyltrimethoxysilane, phenylaminomethyltrimethoxysilane, (N-2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-(N-phenylamino)propyltrimethoxysilane, 3-piperazinylpropylmethyldimethoxysilane, 3-(N,N-dimethylaminopropyl)aminopropylmethyldimethoxysilane, tri[(3-triethoxysilyl)propyl]amine, tri[(3-trimethoxysilyl)propyl]amine, 3-(N,N-dimethylamino)propyltrimethoxysilane, 3-(N,N-dimethylamino)propyltriethoxysilane, (N,N-dimethylamino)methyltrimethoxysilane, (N,Examples of suitable silanes include, but are not limited to, N-dimethylamino)methyltriethoxysilane, bis(3-trimethoxysilyl)propylamine, bis(3-triethoxysilyl)propylamine, and mixtures thereof, particularly preferably 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, aminomethyltrimethoxysilane, aminomethyltriethoxysilane, 3-(N,N-dimethylamino)propyltrimethoxysilane, 3-(N,N-dimethylamino)propyltriethoxysilane, (N,N-dimethylamino)methyltrimethoxysilane, (N,N-dimethylamino)methyltriethoxysilane, bis(3-trimethoxysilyl)propylamine, bis(3-triethoxysilyl)propylamine, and mixtures thereof.

[0056] Examples of useful functional polymeric and / or oligomeric adhesion promoters include, but are not limited to, hydrolyzable PDMS polymers or oligomers, such as PDMS endcapped with trialkoxysilyl(meth)acrylate, dialkoxysilyl(meth)acrylate, or methacrylate groups.

[0057] Adhesion promoters will typically be used in amounts of 0.2 to 40% by weight of the total curable silicone composition, more preferably 1 to 20% by weight.

[0058] The silicone composition optionally includes a desiccant or moisture scavenger. Examples of suitable desiccants are vinyl silanes such as 3-vinylpropyltriethoxysilane, oxime silanes such as methyl-O,O',O''-butan-2-onetrioximosilane or O,O',O'',O'''-butan-2-one-tetraoximosilane, benzamido silanes such as bis(N-methylbenzamido)methylethoxysilane, or carbamato silanes such as carbamatomethyltrimethoxysilane. While methyl-, ethyl-, or vinyl-trimethoxysilane, tetramethyl- or tetraethyl-ethoxysilane can also be used, vinyltrimethoxysilane and tetraethoxysilane are particularly preferred from the standpoint of cost and efficiency. The composition generally contains from about 0 to about 6% by weight.

[0059] In the present composition, an effective amount of plasticizer can be added to ensure the desired workability of the uncured composition and the performance of the final cured composition. Both silicone plasticizers and organic plasticizers can be used in the present invention.

[0060] Suitable plasticizers include, for example, trimethyl-terminated polyorganosiloxanes, petroleum-derived organic oils, polybutenes, alkyl phosphates, polyalkylene glycols, poly(propylene oxide), hydroxyethylated alkylphenols, dialkyldithiophosphonates, poly(isobutylene), poly(α-olefins), and mixtures thereof. The plasticizer component may provide additional oil resistance to the cured elastomer. Thus, from about 1 to about 50 weight percent, preferably from about 10 to about 35 weight percent, of the selected plasticizer can be incorporated into the compositions of the present invention.

[0061] The silicone composition of the present invention may also include one or more crosslinkers. The crosslinker may be a hexafunctional silane, although other crosslinkers may also be used. Examples of such crosslinkers include, for example, methyltrimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, methyltriacetoxysilane, vinyltriacetoxysilane, methyltris(N-methylbenzamido)silane, methyltris-(isopropenoxy)silane, methyltris-(cyclohexylamino)silane, methyltris(methylethylketoximino)silane, vinyltris-(methylethylketoshikimino)silane, methyltris-(methylisobutylketoshikimino)silane, vinyltris-(methylisobutylketoshikimino)silane, tetrakis-(methylethyl)silane, and the like. tetrakis-(methylisobutylketoshikimino)silane, tetrakis-(methylamylketoshikimino)silane, dimethylbis-(methylethylketoshikimino)silane, methylvinylbis-(methylethylketoshikimino)silane, methylvinylbis-(methylisobutylketoshikimino)silane, methylvinylbis-(methylamylketoshikimino)silane, tetrafunctional alkoxyketoxime silane, tetrafunctional alkoxyketoshikimino silane, tris- or tetrakis-enoxy silane, tris- or tetrakis-lactic acid amide silane, and tris- or tetrakis-lactic acid ester silane.

[0062] Typically, the crosslinker used in the present compositions is present at about 1 to about 10% by weight of the total composition, however, the exact concentration of the crosslinker may vary depending on the particular reagent, the desired cure rate, and the molecular weight of the silicone polymer used in the composition.

[0063] The silicone composition of the present invention may also contain other additives, such as conventional additives such as pigments, inhibitors, odor maskers, etc., so long as they do not interfere with the cure mechanism or intended use.

[0064] The crosslinking reaction is a condensation reaction, resulting in the production of a crosslinked network through covalent Si-O-Si bonds between the moisture-reactive components.

[0065] The reaction products of the silicone polymers and compositions of the present invention are useful as adhesives or sealants for bonding, sealing, or encapsulating metal surfaces that are exposed to oil during their intended use. The silicone compositions of the present invention can also be formed into many different configurations and then addition cured. Articles formed in this manner are useful in various industries where oil-resistant silicone elastomer articles are required. In the vehicle assembly industry, for example, O-rings, hoses, seals, and gaskets can be formed from the compositions. Other conventional applications requiring good sealing properties and oil resistance are also contemplated for the compositions of the present invention.

[0066] The CCC bond confers oil resistance at high temperatures to the cured composition. Network silicone polymers and compositions cure by a condensation mechanism in the presence of moisture and a catalyst. The partially crosslinked structure of the network polymers exhibits shorter surface overtime and therefore better green strength. Silicone polymers and compositions are particularly useful as sealants and gaskets for automotive powertrains.

[0067] The curable silicone composition may be applied to a surface that will be exposed to oil during its intended use. The surface to which the composition is applied may be any surface that is exposed to oil, such as the working surface of a conventional internal combustion engine. The method includes applying the composition of the present invention to the working surface. The working surface may be made of a variety of materials, including most metals, glass, commercial or industrial plastics, etc. In yet another aspect of the present invention, a method for using an oil-resistant mechanical seal that remains sealed after exposure to oil is provided. The method includes applying a seal-forming amount of the composition, as described above, to the surface of a mechanical component. The seal is then formed between at least two mechanical surfaces by addition curing through exposure to high temperature conditions, e.g., 150°C, and thereafter the seal remains effective even when exposed to oil for extreme temperature conditions, e.g., for more than 500 hours.

[0068] Yet another aspect of the present invention provides a method for using an oil-resistant sealant that maintains adhesion after contact with and / or immersion in oil. The method comprises forming a seal between two or more surfaces by applying therebetween an oil-resistant sealant formed from a composition according to the present invention. The method includes the steps of (a) providing a silicone sealant; (b) incorporating into the sealant at least about 5 wt. % of a composition comprising magnesium oxide particles having an average particle size of about 0.5 μm to about 1.5 μm and an average surface area of about 50 m² / g to about 175 m² / g; and (c) crosslinking the silicone sealant to form an oil-resistant elastomeric product. Desirably, the sealant composition comprises about 10 to about 90 wt. % silicone polymer, about 1 to about 20 wt. % fumed silica, about 5 to about 50 wt. % precipitated calcium carbonate and / or magnesium oxide, about 1 to about 10 wt. % crosslinker, and about 0.05 to about 5 wt. % moisture-cure catalyst, each based on the weight of the total composition. The sealant composition may also include other optional ingredients including, for example, plasticizers, adhesion promoters, pigments, and the like.

[0069] The moisture-curable composition can be prepared by mixing the moisture-curable network silicone polymer of the present invention, the moisture-curable catalyst, the filler, and optionally other components. This mixing process can be carried out in a suitable dispersing unit, such as a high-speed mixer, a planetary mixer, or a Brabender mixer. In all cases, care must be taken to avoid contact of the mixture with moisture, as this can cause undesired curing. Suitable means are well known in the art: mixing under protective gas in an inert atmosphere, and drying / heating the individual components before addition. [Example]

[0070] Vinyl-terminated PDMS, hydride-terminated PDMS, 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane, Karstedt's catalyst Pt(0), tetramethyldisiloxane, vinyltrimethoxysilane, and methylhydrosiloxane-dimethylsiloxane copolymer (MeHSiO 6–7 mol %) are available from Gelest.

[0071] 1,2,4-Trivinylcyclohexane and dibutyltin dilaurate are available from Sigma-Aldrich.

[0072] Fumed silica is available from Evonik.

[0073] SF105F engine oil is available from the Test Monitoring Center.

[0074] Surface Over Time Measurement: Surface over time was determined under standard climatic conditions (25±2°C, 50±5% relative humidity). A moisture-curable silicone polymer and 0.01 wt% of a dibutyltin dilaurate composition were mixed in a plastic jar to form a composition. A stopwatch was immediately started. The surface was lightly touched with a fingertip until no more composition adhered to the fingertip. Surface over time was recorded in hours.

[0075] Shore 00 Hardness: The procedure followed ASTM D2240-00 using a Shore durometer on a moisture-curable silicone polymer that was fully cured in the presence of a 0.01 wt % dibutyltin dilaurate composition.

[0076] Mechanical properties (tensile test): The elongation at break and tensile stress values (E modulus) were determined using a tensile test in accordance with DIN 53504. Sample dumbbell specimens with dimensions of 2 + / - 0.2 mm thickness, 10 + / - 0.5 mm gauge width, approximately 45 mm gauge length and 9 cm total length were used as test specimens.

[0077] Tests were performed after 7 days of curing. 2 mm thick films were drawn from the materials. After storing the films under standard climatic conditions for 7 days, dumbbells were punched out. Three dumbbells were prepared for each test. Tests were performed under standard climatic conditions. The specimens were allowed to acclimate (i.e., stored) at the test temperature for at least 20 minutes before measurement. The thickness of the specimens was measured at three locations at room temperature using a vernier caliper; for dumbbells, at the ends and in the center of the initial gauge length. The average value was entered into the measurement program. The specimens were clamped in the tensile tester so that the longitudinal axis coincided with the mechanical axis of the machine and the largest possible grip surface was gripped without narrow sections being clamped. The dumbbells were tensioned to a preload of <0.1 MPa at a test speed of 50 mm / min.

[0078] Example 1: Preparation of network silicone polymer A mixture of vinyl-terminated polydimethylsiloxane (MW 55,000 g / mol) (600 g, 14 mmol), 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (1.2 g, 3.48 mmol), hydride-terminated polydimethylsiloxane (MW 1,000 g / mol) (45 g, 48 mmol), and Pt(0) (150 ppm) was stirred at room temperature for 30 minutes. The mixture was heated to 65-70 °C and continued mixing for 3 hours. The product was collected as a colorless, viscous liquid in quantitative yield.

[0079] Comparative Example 2: Preparation of Moisture-Curable Linear Silicone Polymer A mixture of vinyl-terminated polydimethylsiloxane (Mw 140,000 g / mol) (180.0 g, 1.5 mmol), vinyl-terminated polydimethylsiloxane (Mw 55,000 g / mol) (45.0 g, 1.0 mmol), and Pt(0) (200 ppm) was stirred at room temperature for 30 minutes. Tetramethyldisiloxane (5.0 g, 37 mmol) was added and stirred for 30 minutes. The mixture was heated to 60°C and mixing was continued for 3 hours. Excess tetramethyldisiloxane was removed under vacuum at 60°C. Vinyltrimethoxysilane (10.0 g, 13 mmol) was added, and the mixture was stirred at 60°C for 4 hours. The product was collected as a colorless, viscous liquid in quantitative yield.

[0080] Example 3: Preparation of a moisture-curable network silicone polymer A mixture of vinyl-terminated polydimethylsiloxane (MW 140,000 g / mol) (520.0 g, 4.4 mmol), vinyl-terminated polydimethylsiloxane (MW 55,000 g / mol) (130.0 g, 3.0 mmol), 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (0.3 g, 0.87 mmol), and Pt(0) (150 ppm) was stirred at room temperature for 30 minutes. Tetramethyldisiloxane (10.4 g, 77.4 mmol) was added and stirred for 30 minutes. The mixture was heated to 60°C and continued mixing for 3 hours. Excess tetramethyldisiloxane was removed under vacuum at 60°C. Vinyltrimethoxysilane (3.0 g, 20.2 mmol) was added and the mixture was stirred at 60°C for 4 hours. The product was collected as a colorless viscous liquid in quantitative yield.

[0081] Example 4: Preparation of a moisture-curable network silicone polymer A mixture of vinyl-terminated polydimethylsiloxane (Mw 140,000 g / mol) (520.0 g, 4.4 mmol), vinyl-terminated polydimethylsiloxane (Mw 55,000 g / mol) (130.0 g, 3.0 mmol), methylhydrosiloxane-dimethylsiloxane copolymer (MeHSiO 6-7 mol%, Mn 2,000 g / mol) (0.2 g, 0.1 mmol), and Pt(0) (150 ppm) was stirred at room temperature for 30 minutes. Tetramethyldisiloxane (10.4 g, 77.4 mmol) was added and mixed for 30 minutes. The mixture was heated to 60°C and continued mixing for 3 hours. Excess tetramethyldisiloxane was removed under vacuum at 60°C. Vinyltrimethoxysilane (3.5 g, 23.6 mmol) was added, and the mixture was stirred at 60°C for 4 hours. The product was collected as a colorless viscous liquid in quantitative yield.

[0082] Example 5: Preparation of a moisture-curable network silicone polymer A mixture of vinyl-terminated polydimethylsiloxane (MW 140,000 g / mol) (520.0 g, 4.4 mmol), vinyl-terminated polydimethylsiloxane (MW 55,000 g / mol) (130.0 g, 3.0 mmol), 1,2,4-trivinylcyclohexane (0.3 g, 1.8 mmol), and Pt(0) (150 ppm) was stirred at room temperature for 30 minutes. Tetramethyldisiloxane (10.4 g, 77.4 mmol) was added and mixed for 30 minutes. The mixture was heated to 60°C and continued mixing for 3 hours. Excess tetramethyldisiloxane was removed under vacuum at 60°C. Vinyltrimethoxysilane (3.5 g, 23.6 mmol) was added, and the mixture was stirred at 60°C for 4 hours. The product was collected as a colorless, viscous liquid in quantitative yield.

[0083] Example 6: Preparation of a moisture-curable network silicone polymer A mixture of vinyl-terminated polydimethylsiloxane (MW 55,000 g / mol) (600 g, 14 mmol), 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (1.2 g, 3.48 mmol), hydride-terminated polydimethylsiloxane (MW 1,000) (45 g, 48 mmol), and Pt(0) (150 ppm) was stirred at room temperature for 30 minutes. The mixture was heated to 65-70 °C and continued mixing for 3 hours. Vinyltrimethoxysilane (12 g, 81 mmol) was added, and the mixture was stirred at 65-70 °C for 3 hours. The product was collected as a colorless, viscous liquid in quantitative yield.

[0084] Example 7: Properties of Moisture-Curable Silicone Polymers [Table 1]

[0085] [Table 2]

[0086] As shown in Table 1 above, the network polymers of Examples 3-6 typically had higher weight average molecular weights (MW), broader molecular weight distributions (PDI), and similar viscosities than the linear polymer of Comparative Example 2. The network polymers exhibited faster surface cure rates (surface over time) than the linear polymer in the presence of 0.1% dibutyltin dilaurate. As shown in Figure 1, the viscosity of the network silicone polymer of Example 6 (square dots) decreased at a faster rate than the linear silicone polymer of Comparative Example 2 (triangle dots).

[0087] The network silicone polymers of Examples 3, 4, and 6 have higher Shore OO hardness than the linear polymers. The network silicone polymer of Example 5 has a Shore OO hardness value similar to the linear silicone polymer, which may be due to incomplete curing from the non-silicone compound, trivinylcyclohexane, resulting in a stiffer network structure.

[0088] 2 also shows the GPC values of Comparative Example 2 and Example 6. Both have similar peak average molecular weights (Mp) of about 115,599, but Example 6 (dotted line) has a broader PDI, indicating lower and higher molecular weight fractions in the polymer of Example 6. However, Example 6 has only a slightly higher viscosity than Comparative Example 2 (straight line), but provides a network structure.

[0089] Comparative Example 2 showed that the linear polymer had a higher elongation than the network polymer of Example 6. The network silicone polymer had a higher modulus than the linear polymer both initially and after aging. Fully cured samples of the network silicone polymer showed lower elongation and higher modulus than the linear polymer in both the initial and aged samples of SF105F oil at 150°C for 100 hours.

[0090] Many modifications and variations of this invention can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. The specific embodiments described herein are offered by way of example only, and the present invention is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

1. (i) 10 to 98 wt. % of a vinyl-terminated polyorganosiloxane having a weight average molecular weight greater than 1,000 g / mol; (ii) 1 to 20 wt. % of a hydride-terminated polyorganosiloxane having a weight average molecular weight of less than 100,000 g / mol; (iii) 0.001 to 20% by weight of a vinyl polyfunctional organic compound, and (iv) 0.00001 to 5 wt. % of a hydrosilylation catalyst; A network silicone polymer prepared by the molar ratio of vinyl functional groups to hydride functional groups is 0.1 to 0.8; A network silicone polymer, wherein the weight average molecular weight of the network silicone polymer is 10,000 to 3,000,000 g / mol.

2. (i) The vinyl-terminated polyorganosiloxane is １ R ２ SiO) units, where R １ and R ２ 10. The network silicone polymer of claim 1, wherein is independently alkyl, aryl, fluoroalkyl, trialkylsilyl, triarylsilyl, or a combination thereof.

3. (ii) the hydride-terminated polyorganosiloxane is a monomer (R １ R ２ SiO) units, wherein R １ and R ２ 10. The network silicone polymer of claim 1, wherein is independently alkyl, aryl, fluoroalkyl, trialkylsilyl, triarylsilyl, or a combination thereof.

4. (iii) The vinyl polyfunctional organic compound is a monomer (R １ R ２ SiO) ｍ and (R ３ R ４ SiO) ｑ A copolymer having both formulae of units, wherein R １ and R ２ are independently alkyl, aryl, fluoroalkyl, trialkylsilyl, triarylsilyl, or a combination thereof; R ３ is vinyl, allyl, or a combination thereof; R ４ is R ３ , alkyl, aryl, fluoroalkyl, trialkylsilyl, triarylsilyl, or a combination thereof, wherein the ratio of m / q is from 0 to 200; 10. The network silicone polymer of claim 1, wherein the copolymer has a weight average molecular weight of less than 100,000 g / mol.

5. A moisture-curable network silicone polymer prepared from the reaction product comprising: (A) a network silicone polymer prepared by: (i) 10 to 98 wt. % of a vinyl-terminated polyorganosiloxane having a weight average molecular weight greater than 1,000 g / mol; (ii) 1 to 20 wt. % of a hydride-terminated polyorganosiloxane having a weight average molecular weight of less than 100,000 g / mol; (iii) 0.001 to 20% by weight of a vinyl polyfunctional organic compound, and (iv) 0.00001 to 5 wt. % of a hydrosilylation catalyst; the molar ratio of vinyl functional groups to hydride functional groups is 0.1 to 0.8; a network silicone polymer, wherein the weight average molecular weight of the network silicone polymer is 10,000 to 3,000,000 g / mol; (B) End-capped vinyl-functional silane CH ２ =CH-SiY ｎ R ３－ｎ wherein Y is alkoxy, aryloxy, acetoxy, oximino, enoxy, amino, α-hydroxycarboxylic acid amide (—OCR′ ２ CONR” ２ ), α-hydroxycarboxylic acid ester (—OCR′ ２ COOR"), H, OH, halogen, or a combination thereof; n=1, 2, or 3; and each R, R', and R" is independently an alkyl, aryl, fluoroalkyl, trialkylsilyl, triarylsilyl, or a combination thereof; the ratio of vinyl functional groups of (B) the end-capped vinyl functional silane to the free hydride functional groups of (A) the silicone polymer is 1 to 1.5; Moisture-curing network silicone polymer.

6. (1) 10-90% moisture-curable silicone polymer prepared from the reaction product comprising: (A) a network silicone polymer prepared by: (i) 10 to 98 wt. % of a vinyl-terminated polyorganosiloxane having a weight average molecular weight greater than 1,000 g / mol; (ii) 1 to 20 wt. % of a hydride-terminated polyorganosiloxane having a weight average molecular weight of less than 100,000 g / mol; (iii) 0.001 to 20% by weight of a vinyl polyfunctional organic compound, and (iv) 0.00001 to 5 wt. % of a hydrosilylation catalyst; the molar ratio of vinyl functional groups to hydride functional groups is 0.1 to 0.8; a network silicone polymer, wherein the weight average molecular weight of the network silicone polymer is 10,000 to 3,000,000 g / mol; (B) End-capped vinyl-functional silane CH ２ =CH-SiY ｎ R ３－ｎ wherein Y is alkoxy, aryloxy, acetoxy, oximino, enoxy, amino, α-hydroxycarboxylic acid amide (—OCR′ ２ CONR” ２ ), α-hydroxycarboxylic acid ester (—OCR′ ２ COOR"), H, OH, halogen, or a combination thereof; n=1, 2, or 3; and each R, R', and R" is independently an alkyl, aryl, fluoroalkyl, trialkylsilyl, triarylsilyl, or a combination thereof; the ratio of vinyl functional groups of (B) the end-capped vinyl functional silane to the free hydride functional groups of (A) the silicone polymer is 1 to 1.5; (2) 0.00001 to 5% of a moisture-curing catalyst; (3) optionally, 5-90% of a finely divided inorganic filler or mixture of fillers; A moisture-curable composition comprising:

7. 7. The moisture-curable composition of claim 6, wherein the filler is selected from the group consisting of silicone resins, organic fillers, plastic powders, and combinations thereof.

8. The moisture-curable composition of claim 6 further comprising a reactive silane.

9. The composition of claim 6 which is an adhesive or sealant.

10. The composition of claim 9, wherein the adhesive or sealant is an automotive gasket.

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