Moisture-curable polyacrylate compositions and uses thereof

Abstract

Moisture-curable polyacrylate polymers and compositions containing the polyacrylate polymers are provided, which have pendant moisture-reactive silyl functional groups attached to the polymer chain. The polyacrylate polymers and compositions cure via a condensation mechanism in the presence of moisture and a catalyst. The moisture-curable polyacrylate polymers and compositions of the present invention have excellent resistance to automotive oils at high temperatures, making them particularly useful as sealants and gaskets in automotive powertrains.

Description

[Technical Field]

[0001] The present invention relates to a moisture-curable polyacrylate and a composition thereof. The moisture-curable polyacrylate and a composition thereof exhibit good petroleum resistance and heat resistance, and are particularly suitable as room-temperature vulcanizing sealants and adhesives for automotive gaskets. [Background technology]

[0002] Curable polyacrylates and compositions are used as adhesives, sealants, coatings, paints, and encapsulants in a wide range of applications, including packaging, automotive, construction, highways, electronics, appliance assembly, and consumer products. Polyacrylate polymers are an important class of polymers, characterized by their soft, tough, and rubber-like properties. Their glass transition temperatures are significantly lower than room temperature. They are known for their high transparency, good impact strength, and resilience, and they have good heat resistance up to 450 K under dry heat. The absence of double bonds in the backbone also contributes to their excellent weatherability and ozone resistance.

[0003] Typically, the curable polyacrylates and compositions used in these applications are tailored to provide strength, toughness, cure rate, modulus, elongation, and resistance to high temperatures, oil, and humidity. For example, curable polyacrylates and compositions can be formed into gaskets, which are widely used in the automotive industry. During use, polyacrylate compositions are exposed to a variety of conditions and must continue to function without loss of integrity. One such condition is exposure to hot engine oil. Ethyl and acrylate polyacrylate polymers exhibit excellent resistance to petroleum-based fuels and oils, and can maintain their properties even when sealing petroleum at temperatures as high as 300°F. These properties make polyacrylates suitable for applications such as automotive automatic transmissions and steering systems, as well as other applications requiring resistance to oil and high temperatures. Polyacrylates are not recommended for applications where the elastomer will be exposed to brake fluid, chlorinated hydrocarbons, alcohols, or glycols.

[0004] Oil-resistant materials are described in U.S. Pat. Nos. 3,326,868, 2,492,170, 3,315,012, and 3,445,403, wherein the thermosetting acrylate rubber comprises, in an aqueous emulsion, (a) 50 to 99.8 weight percent of b-methoxy- or b-ethoxyethyl acrylate; (b) 0 to 40 weight percent of one or more rubber-forming alkyl or cyanoalkyl esters of acrylic or methacrylic acid, the homopolymers of which have a second-order transition temperature of less than 10° C.; (c) 0 to 20 weight percent of acrylonitrile; prepared by polymerizing (d) 0.2 to 2.5 weight percent of N-alkoxymethyl-acrylamides or -methacrylamides, the alkoxy groups containing 1 to 8 carbon atoms; and (e) 0 to 3.8 weight percent of monoolefinically, terminally unsaturated amides containing at least one hydrogen on the amide nitrogen, where the olefinic unsaturation is α-β to the carbonyl group of the amide and the remainder of the molecule consists solely of hydrogen atoms or carbon and hydrogen atoms, wherein the sum of components (d) and (e) does not exceed 4 weight percent. U.S. Patent Nos. 3,875,092, 3,910,866, and 4,405,758 also disclose compounding a heat- or dual-curable acrylate rubber having both carboxyl and active halogen groups with a combination of sodium stearate and tetramethylthiuram disulfide or its metal compounds of groups IB, IIB, IVA, VA, and VIA to provide a composite acrylate rubber having an excellent scorch / cure rate balance and desirable physical properties in the vulcanizate. However, the above techniques do not teach moisture-curable compositions.

[0005] U.S. Patents 7,129,294, 6,274,688, 6,420,492, 6,441,101, 6,667,369, 4,334,036, 7,439,308, 7,276,574, and 5,986,014 disclose oil-resistant (meth)acrylic polymers having high functional groups at the chain ends with alkenyl groups or curable silyl groups, which polymers are produced by the following process: (i) preparing a (meth)acrylic polymer having halogen atoms at the chain ends, using an organic halogen compound or a halosulfonyl compound as an initiator and a metal complex catalyst having a central metal atom selected from the group consisting of elements in Groups 8, 9, 10, and 11 of the periodic table; and (ii) converting the halogen atoms into alkenyl or curable silyl group-containing substituents. The resulting (meth)acrylic polymer forms a homogeneous curable material. The method for producing these crosslinkable silyl-terminated (meth)acrylic polymers involves adding a crosslinkable silyl-terminated hydrosilane compound to an alkenyl-terminated (meth)acrylic polymer (A) prepared by atom transfer radical polymerization in the presence of a platinum hydrosilylation catalyst. The amount of platinum hydrosilylation catalyst used is 0.1 to 10 mg, calculated as platinum metal, per kg of alkenyl-terminated (meth)acrylic polymer (A). The present invention provides a method for producing crosslinkable silyl-terminated (meth)acrylic polymers. These moisture-curable alkoxysilane-terminated polyacrylates are commercially available from Kaneka Corporation, Japan, and are currently prepared by a two-step process. The disclosed process involves bromination with an unsaturated carboxylic acid followed by hydrosilylation with an alkoxysilane. This two-step process is expensive and time-consuming for manufacturers.

[0006] Therefore, it would be desirable to identify simple alternative synthetic schemes for making moisture-curable polyacrylates and compositions that involve increased availability of raw reactants and reduced complexity of the polymer structure and its synthesis. The present invention fulfills this need. Summary of the Invention [Means for solving the problem]

[0007] The present invention provides moisture-curable polyacrylates and compositions thereof formed by random polymerization, which retain their mechanical properties even after prolonged exposure to high temperatures in petroleum, and are particularly suitable as sealants and adhesive flanges in automotive powertrains.

[0008] One aspect of the present invention relates to polyacrylate polymers having pendant alkoxy or other moisture-reactive silyl functional groups attached to the polymer chain.

[0009] Polyacrylate polymers include: i. 20 to 70% by weight of CH2=CR 1 COOR 2 (In the formula, R 1 is H or CH3, R 2 is a C4-24 linear, branched, or cyclic alkyl chain, or a combination thereof; ii. 20 to 70 wt% CH2=CR 1 COXR 3 (In the formula, R 1 is H or CH3; X is O, NR 3 ,S;R 3 is H, a C1-2 alkyl chain, or a combination thereof; and iii. 0.1 to 10% by weight CH 2 =CR 1 COOR 4 SiR 5 3-n Y n (In the formula, R 1 is H or CH3;R 4 is a C1-24 linear, branched or cyclic alkylene or arylene chain; R 5is a C1-24 straight, branched, or cyclic alkyl chain; Y is a C1-3 alkoxy, aryloxy, acetoxy, oximino, enoxy, amino, ester, amide, lactate ester, lactamide, H, OH, halogen, or a combination thereof; and n=1, 2, or 3. It is prepared using

[0010] Yet another aspect of the present invention relates to a method of forming a moisture-curable polyacrylate polymer, the method comprising the steps of: 1) Polymerizing the following for about 4 to 24 hours at a reaction temperature of about 50 to about 120°C: a. 40 to 90% by weight of the following mixtures i. 20 to 70% by weight of CH2=CR 1 COOR 2 (In the formula, R 1 is H or CH3, R 2 is a C4-24 linear, branched, or cyclic alkyl chain, or a combination thereof; ii. 20 to 70 wt% CH2=CR 1 COXR 3 (In the formula, R 1 is H or CH3; X is O, NR 3 , S;R 3 is H, a C1-2 alkyl chain, or a combination thereof; and iii. 0.1 to 10% by weight CH 2 =CR 1 COOR 4 SiR 5 3-n Y n (In the formula, R 1 is H or CH3;R 4 is a C1-24 linear, branched or cyclic alkylene or arylene chain; R 5is a C1-24 straight, branched, or cyclic alkyl chain; Y is a C1-3 alkoxy, aryloxy, acetoxy, oximino, enoxy, amino, ester, amide, lactate ester, lactamide, H, OH, halogen, or a combination thereof; and n=1, 2, or 3. b. 10 to 60% by weight of formula HOR 6 (In the formula, R 6 is C 1-4 ) alcohols, c. 0 to 60% by weight of formula R 7 COOR 8 (In the formula, R 7 and R 8 is independently C 1-4 an alkyl chain.) ester, d. 0.01 to 5% azo or peroxide radical initiator; 2) removing the solvent and volatile materials under a vacuum of about 10 to 30 psi at a temperature of about 50 to about 120°C; Including, The resulting polyacrylate polymer has a weight average molecular weight (Mw) of about 1,000 g / mol to about 100,000 g / mol and a PDI of about 1.5-10.

[0011] Another aspect of the present invention is a method for producing a composition comprising: 1) A moisture-curing polyacrylate polymer prepared from about 10 to 90 weight percent of: i. 20 to 70% by weight of CH2=CR 1 COOR 2 (In the formula, R 1 is H or CH3, R 2 is a C4-24 linear, branched, or cyclic alkyl chain, or a combination thereof; ii. 20 to 70 wt% CH2=CR 1 COXR 3 (In the formula, R 1 is H or CH3; X is O, NR 3 , S;R 3is H, a C1-2 alkyl chain, or a combination thereof; and iii. 0.1 to 10% by weight CH 2 =CR 1 COOR 4 SiR 5 3-n Y n (In the formula, R 1 is H or CH3;R 4 is a C1-24 linear, branched or cyclic alkylene or arylene chain; R 5 is a C1-24 straight, branched, or cyclic alkyl chain; Y is a C1-3 alkoxy, aryloxy, acetoxy, oximino, enoxy, amino, ester, amide, lactate ester, lactamide, H, OH, halogen, or a combination thereof; and n=1, 2, or 3. 2) about 5 to about 90% finely divided inorganic filler or mixture of fillers; 3) about 0.001 to about 0.5 wt. % of a moisture or acid scavenger, or a combination thereof; 4) about 0.001 to about 5 wt. % of a moisture cure catalyst; and 5) optionally, up to about 10% by weight of crosslinkers, adhesion promoters, plasticizers, acid scavengers, pigments, inhibitors, and / or deodorizers; The present invention relates to a moisture-curable composition comprising: [Brief explanation of the drawings]

[0012] [Figure 1] Figure 1 shows the viscosity of the polymer as a function of frequency. [Figure 2] Figure 2 shows the dynamic mechanical analysis (DMA) of the polymer. DETAILED DESCRIPTION OF THE INVENTION

[0013] Detailed Description of the Invention Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. In case of conflict, the present specification, including definitions, will control. Preferred methods and materials are described below, although methods and materials similar or equivalent to those described herein can be used in the practice or testing of this disclosure. 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.

[0014] As used in this specification and claims, the term "comprising" can include 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 named components / steps and permit the presence of other components / steps. However, such descriptions should also be construed as describing compositions or processes as "consisting of" and "consisting essentially of" the listed components / steps, permitting only the named components / steps to be present along with impurities that may result therefrom, and excluding other components / steps.

[0015] Numerical values ​​in the specification and claims, although they relate specifically to polymers or polymer compositions, reflect average values ​​for compositions that may include individual polymers with different properties. Furthermore, unless otherwise indicated, a numerical value should be understood to include values ​​that are the same when reduced to the same significant figure, and values ​​that differ from the stated value by less than experimental error using conventional measuring techniques of the type described herein to determine the value.

[0016] All ranges disclosed herein are inclusive of the recited endpoints and are independently combinable (e.g., the range "from 2 to 10" includes the endpoints 2 and 10, and all intermediate values). The endpoints of the ranges and any values ​​disclosed herein are not limited to the exact ranges or values, but are sufficiently imprecise to include values ​​that approximate these ranges and / or values. As used herein, approximating language may be applied to modify any quantitative expression that can be varied without resulting in a change in the basic function to which it is associated. Thus, a value modified by a term such as "about" may, in some cases, not be limited to the exact value specified. In at least some instances, approximating language may correspond to the precision of the instrument for measuring the value. The modifier "about" should also be considered to disclose a range defined by the absolute values ​​of the two endpoints. For example, the phrase "from about 2 to about 4" also discloses a range of "from 2 to 4." The term "about" may refer to plus or minus 10% of the indicated numerical value. 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; for example, "about 1" may mean 0.5 to 1.4.

[0017] As used herein, a polymer or oligomer is a macromolecule consisting of monomeric units equal to or greater than about one monomeric unit. Polymer and oligomer, or polymeric and oligomeric, are used interchangeably herein for the purposes of the present invention.

[0018] As used herein, the term "alkyl" refers to a monovalent straight, cyclic, or branched moiety containing C1 to C24 carbons and containing only single bonds between carbon atoms within 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.

[0019] 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 (fused) rings, in which at least one ring is aromatic (e.g., naphthyl, dihydrophenanthrenyl, fluorenyl, anthryl). Preferred examples include phenyl, methylphenyl, ethylphenyl, methylnaphthyl, ethylnaphthyl, and the like.

[0020] As used herein, the term "alkoxy" refers to the group --OR, where R is alkyl as defined above.

[0021] As used herein, the above groups may be further substituted or unsubstituted. When substituted, a hydrogen atom on the group may be replaced by an 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-thio Substituted with one or more substituents independently selected from carbamyl, C-amido, N-amido, S-sulfonamido, N-sulfonamido, C-carboxy, protected C-carboxy, O-carboxy, isocyanato, thiocyanato, isothiocyanato, nitro, silyl, sulfenyl, sulfinyl, sulfonyl, haloalkyl, haloalkoxy, trihalomethanesulfonyl, trihalomethanesulfonamido, and 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, such as cycloalkyl, cycloalkenyl, cycloalkynyl, and heterocyclyl.

[0022] As used herein, the term "polyacrylate" refers to an acrylic polymer, acrylate, or acrylic, acrylic resin, which are used interchangeably herein in the present invention.

[0023] 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 chain brought about by water or moisture in the air in the presence of a moisture cure catalyst.

[0024] The present invention provides the art with polyacrylate polymers containing pendant alkoxy or other moisture-reactive silyl functional groups attached to the polymer chain. These polyacrylate polymers, when combined with other ingredients such as moisture and acid scavengers, moisture-cure catalysts, fillers, and adhesion promoters, provide moisture-curable compositions. The selection and relative amounts of the specific moisture-reactive silyl-functional acrylic and vinyl monomers comprising the polyacrylate composition used in the moisture-curable compositions of the present invention depend on the desired final properties of the sealant and the intended end use. Adjustable concentrations of pendant moisture-curable functional groups on the polymer backbone will result in faster cure rates for the sealant, as needed. The selection of acrylic and vinyl monomers and their relative amounts in a polyacrylate polymer composition to achieve desired properties is within the expertise of those skilled in the art. The present invention provides the art with a novel class of polyacrylate compositions that have storage-stable pendant moisture-curable silyl groups and are moisture-curable. In particular, these polymers exhibit oil resistance at 150°C for 500 hours or more, and even 1,000 hours or more.

[0025] In one embodiment of the present invention, the polyacrylate polymer having pendant moisture-curable functional groups is selected from the group consisting of: i. 20 to 70% by weight of CH2=CR 1 COOR 2 (In the formula, R 1 is H or CH3, R 2 is a C4-24 linear, branched, or cyclic alkyl chain, or a combination thereof; ii. 20 to 70 wt% CH2=CR 1 COXR 3 a second acrylic or methacrylic acid derivative having the structure 1 is H or CH3; X is O, NR 3 , S;R 3 is H, a C1-2 alkyl chain, or a combination thereof, and iii. 0.1 to 10% by weight CH 2 =CR1 COOR 4 SiR 5 3-n Y n (In the formula, R 1 is H or CH3;R 4 is a C1-24 linear, branched or cyclic alkylene or arylene chain; R 5 is a C1-24 straight, branched, or cyclic alkyl chain; Y is a C1-3 alkoxy, aryloxy, acetoxy, oximino, enoxy, amino, ester, amide, lactate ester, lactamide, H, OH, halogen, or a combination thereof; and n=1, 2, or 3. It is prepared by polymerizing

[0026] Yet another aspect of the present invention relates to a method of forming a moisture-curable polyacrylate polymer, the method comprising the steps of: 1) polymerizing the following for about 4 to 24 hours at a reaction temperature of about 50 to about 120°C: a. 40 to 90% by weight of the following mixtures i. 20 to 70% by weight of CH2=CR 1 COOR 2 (In the formula, R 1 is H or CH3, R 2 is a C4-24 linear, branched, or cyclic alkyl chain, or a combination thereof; ii. 20 to 70 wt% CH2=CR 1 COXR 3 (In the formula, R 1 is H or CH3; X is O, NR 3 , S;R 3 is H, a C1-2 alkyl chain, or a combination thereof; and iii. 0.1 to 10% by weight CH 2 =CR 1 COOR 4 SiR 5 3-n Y n (In the formula, R 1 is H or CH3;R 4 is a C1-24 linear, branched or cyclic alkylene or arylene chain; R 5 is a C1-24 straight, branched, or cyclic alkyl chain; Y is a C1-3 alkoxy, aryloxy, acetoxy, oximino, enoxy, amino, ester, amide, lactate ester, lactamide, H, OH, halogen, or a combination thereof; and n=1, 2, or 3. e. 10 to 60% by weight of formula HOR 6 (In the formula, R 6 is C 1-4 ) alcohols, f. 0 to 60% by weight of formula R 7 COOR 8 (In the formula, R 7 and R 8 is independently C 1-4 an alkyl chain.) ester, g. 0.01-5% azo or peroxide radical initiator. 2) removing the solvent and volatile materials under a vacuum of about 10 to 30 psi at a temperature of about 50 to about 120°C; and The resulting polyacrylate polymers have a weight average molecular weight (Mw) of about 1,000 g / mol to about 100,000 g / mol and a PDI of about 1.5-10.

[0027] The monomers of components (i), (ii), and (iii) above are converted to polyacrylates by polymerization. For polymerization, the monomers are selected so that the resulting polymer can be used as a polyacrylate, particularly so that the resulting polymer has oil resistance properties in accordance with "Handbook of Specialty Elastomers," edited by Robert C. Klingender, and "Specialty and High Performance Rubber: Materials in Use and Their Marketplace," by Peter W. Dufton. For these applications, the static glass transition temperature of the resulting polymer will advantageously be below about -25°C to about -30°C.

[0028] CH2=CR 1 COOR 2 Examples of the first acrylic or methacrylic acid derivative having the structure include n-butyl acrylate, n-butyl methacrylate, n-pentyl acrylate, n-hexyl acrylate, n-heptyl acrylate, and n-octyl acrylate, n-nonyl acrylate, lauryl methacrylate, cyclohexyl acrylate, and branched (meth)acrylic isomers such as i-butyl acrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl acrylate, stearyl methacrylate, isooctyl acrylate, or combinations thereof.

[0029] Structure CH2=CR 1 COOXR 3 Examples of the second acrylic or methacrylic acid derivative having the formula include methyl acrylate, ethyl acrylate, methoxyethyl acrylate, ethyl methacrylate, methyl methacrylate, or combinations thereof.

[0030] formula CH 2 =CR 1 COOR 4 SiR 53-n Y n Examples of silane-functional acrylic or methacrylic acid derivatives having the formula (I) include trimethoxysilylpropyl(meth)acrylate, triethoxysilylpropyl(meth)acrylate, trimethoxysilylethyl(meth)acrylate, methyldimethoxysilylpropyl(meth)acrylate, (meth)acryloxypropylSi(OCHCHCON(CH)), (meth)acryloxypropylSi(OCHCHCOOCHCH), or combinations thereof.

[0031] Polyacrylate polymers can be prepared by solution, emulsion, or bulk polymerization procedures using well-known polymerization techniques, such as free radical, anionic, and cationic techniques. The polymers can then be formed into neat polymers after solvent removal, latex coagulation, or melt processing.

[0032] The polymerization is carried out in the presence of one or more organic solvents. Suitable organic solvents or solvent mixtures include alkanes such as hexane, heptane, octane, and isooctane; aromatic hydrocarbons such as benzene, toluene, and xylene; esters such as ethyl acetate, propyl, butyl, and heptyl; halogenated hydrocarbons such as chlorobenzene; alcohols such as methanol, ethanol, isopropanol, ethylene glycol, and ethylene glycol; ethers such as THF, diethyl ether, and dibutyl ether; or mixtures thereof.

[0033] In one advantageous embodiment of the process, the polymerization reaction proceeds in isopropanol using AIBN as the radical initiator. In another variation, the polymerization reaction is carried out using a mixture of isopropanol and ethyl acetate. The acrylic polymers prepared will generally have a weight average molecular weight (Mw) of 1,000 to 2,000,000 g / mol, more preferably 1,000 to 100,000 g / mol. Mw is determined by gel permeation chromatography (GPC) or matrix-assisted laser desorption / ionization mass spectrometry (MALDI-MS).

[0034] Another aspect of the present invention relates to a moisture-curable composition comprising: 1) A moisture-curing polyacrylate polymer prepared from about 10 to 90 weight percent of: i. 20 to 70% by weight of CH2=CR 1 COOR 2 (In the formula, R 1 is H or CH3, R 2 is a C4-24 linear, branched, or cyclic alkyl chain, or a combination thereof; ii. 20 to 70 wt% CH2=CR 1 COXR 3 (In the formula, R 1 is H or CH3; X is O, NR 3 , S;R 3 is H, a C1-2 alkyl chain, or a combination thereof; and iii. 0.1 to 10% by weight CH 2 =CR 1 COOR 4 SiR 5 3-n Y n (In the formula, R 1 is H or CH3;R 4 is a C1-24 linear, branched or cyclic alkylene or arylene chain; R 5is a C1-24 straight, branched, or cyclic alkyl chain; Y is a C1-3 alkoxy, aryloxy, acetoxy, oximino, enoxy, amino, ester, amide, lactate ester, lactamide, H, OH, halogen, or a combination thereof; and n=1, 2, or 3. 2) about 5 to about 90% finely divided inorganic filler or mixture of fillers; 3) about 0.001 to about 0.5 wt. % of a moisture or acid scavenger, or a combination thereof; 4) about 0.001 to about 5 wt. % of a moisture cure catalyst; and 5) Optionally, up to about 10% by weight of a crosslinker, adhesion promoter, plasticizer, acid scavenger, pigment, inhibitor, and / or deodorizer.

[0035] The moisture-curable polyacrylate polymer is stripped of solvent to a content of less than 1% by weight, preferably less than 0.1% by weight, and then the filler and moisture-cure catalyst are added. This process is preferably carried out in a batch reactor, or in a planetary mixer, a condensing extruder such as a vented extruder, a ring extruder, a single-screw extruder, or a twin-screw extruder, all of which are known to those skilled in the art.

[0036] The fillers useful in the present invention are finely divided inorganic fillers. By "finely divided," it is meant that the average particle size of the filler is less than about 5 microns. Advantageously, the inorganic filler has an average particle size 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 less than 2 microns; and ii) at least about 65% of the inorganic fillers have a diameter less than 1 micron. The filler may be present in an amount of at least about 15% of the total composition. Desirably, the filler is present in an amount of about 25% to about 80% by weight of the total composition, more desirably, about 25% to about 60% by weight.

[0037] The moisture-curable polyacrylate composition of the present invention contains certain fillers to help impart oil resistance to the final cured composition. The fillers have basic properties so that they are available to react with any acidic by-products formed in the working environment in which the composition of the present invention is intended to be used. In doing so, the fillers neutralize these by-products before they degrade the elastomer, thereby improving adhesive retention. These fillers include, for example, lithopone, zirconium silicate, diatomaceous earth, calcium clay, hydroxides such as those of calcium, aluminum, magnesium, and iron, carbonates such as sodium, potassium, calcium, and magnesium carbonates, metal oxides such as oxides of zinc, magnesium, chromium, zirconium, aluminum, and titanium, and ferric oxide, and mixtures thereof. The filler can be present in the curable composition at any suitable concentration.

[0038] 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, Inc. 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.

[0039] In addition to the precipitated calcium carbonate, the compositions of the present invention may also include a basic filler component, such as magnesium oxide particles. Desirably, the magnesium oxide is present in an amount of about 5 to about 50% by weight of the total composition, e.g., about 10 to about 25% by weight. Any magnesium oxide satisfying the above physical characteristics can be used in accordance with the present invention. Desirably, the magnesium oxide of the present invention is MAGCHEM 50M or MAGCHEM 200-AD, commercially available from Martin Marietta Magnesia Specialties, Inc., Baltimore, MD. 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.

[0040] Another type of desirable filler is reinforcing silica. The silica may be fumed silica, either untreated or treated with an adjuvant to impart hydrophobicity. 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 concentration varies depending on the properties of the particulate silica, it has been observed that the thixotropic effect of silica can result in impractically high viscosity compositions before the reinforcing effect is maximized. Hydrophobic silicas tend to have a lower thixotropic effect, and therefore can be included in larger amounts to achieve a desired composition consistency. Therefore, the amount of silica selected must balance the desired reinforcing effect with a practical viscosity. Hexamethyldisilazane-treated fumed silica is particularly preferred (HDK2000, Wacker-Chemie, Burghausen, Germany). A commercially available example of fumed silica suitable for use in the present invention is sold by Degussa under the trade name AEROSIL® 8200.

[0041] A thixotropic agent may be desirable as a filler 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% of the total composition. A typical example of such a thixotropic agent is fumed silica, either untreated or treated to alter its surface chemistry. Virtually any reinforcing fumed silica can be used. Examples of such treated fumed silica include polydimethylsiloxane-treated silica and hexamethyldisilazane-treated silica. Such treated silicas are commercially available, for example, under the trade names CABSIL ND-TS from Cabot Corporation and AEROSIL R805 from Evonik AEROSIL. Among the untreated silicas, amorphous silica and hydrous silica can 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 Industry Co., Ltd.), which has an average particle size of 1.0 nm. Other fillers suitable 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 available from BASF under the trade name PLURACOL V-10.

[0042] Other conventional fillers can also be incorporated into the compositions of the present invention, provided they impart basicity to the composition and do not adversely affect the oil-resistant cure mechanism and adhesive properties of the final product. Generally, any suitable mineral, carbonaceous, glass, or ceramic filler can 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 powder; graphite; synthetic fibers, and mixtures thereof. Fillers can be used in amounts ranging from about 5 to about 70 weight percent of the total composition. A commercially available example of a precipitated silica filler suitable for use in the present invention is sold by JM Huber under the trade name ZEOTHIX 95.

[0043] Organic fillers can also be used, especially acrylic resins, wood fibers, wood flour, sawdust, cellulose, cotton, pulp, cotton, wood chips, shredded straw, and rice husks. Additionally, short fibers such as glass fibers, glass filaments, polyacrylonitrile, carbon fibers, Kevlar fibers, or polyethylene fibers can also be added.

[0044] To enhance the storage stability of the moisture-curable polyacrylate composition, moisture scavengers may be added to remove any moisture from the ambient environment or raw materials. Examples of moisture scavengers include vinyltrimethoxysilane, vinylmethyldimethoxysilane, hexamethyldisilazane, methyltriethoxysilane, 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 carbamate silanes such as carbamatemethyltrimethoxysilane, or combinations thereof. Methyl, ethyl, or vinyltrimethoxysilane, tetramethyl- or tetraethyl-ethoxysilane, are also possible. Vinyltrimethoxysilane and tetraethoxysilane are particularly preferred for their cost and efficiency. The composition generally contains up to about 6% by weight.

[0045] The moisture-cure catalyst initiates moisture cure of the composition in the presence of moisture. The crosslinking reaction is a condensation reaction, resulting in a crosslinked network product with Si-O-Si covalent bonds between the moisture-reactive components. The catalyst can be a metallic or non-metallic catalyst. Examples of metallic catalysts useful in the present invention include tin, titanium, zinc, zirconium, lead, iron, cobalt, antimony, manganese, and bismuth organometallic compounds. Examples of non-metallic catalysts include amines, amidines, and tetramethylguanidine.

[0046] In one embodiment, moisture cure catalysts useful for accelerating the moisture cure of polyacrylate compositions include, but are not limited to, dibutyltin dilaurate, dimethyldineodecanoatetin, dioctyltin didecyl mercaptide, bis(neodecanoyloxy)dioctylstannane, dimethylbis(oleoyloxy)stannane, dibutyltin diacetate, dibutyltin dimethoxide, stannous octoate, isobutyltin ditriceroate, dibutyltin dioxide, solubilized dibutyltin oxide, dibutyltin bis(isobutyltin dimethoxide), dibutyltin diiso ... The tin ester may be selected from diisooctyl phthalate, bis-trippropoxysilyldioctyltin, dibutyltin bisacetylacetone, silylated dibutyltin dioxide, carbomethoxyphenyltin trisuberate, isobutyltin triceleroate, dimethyltin dibutyrate, dimethyltin dineodecanoate, triethyltin tartrate, dibutyltin dibenzoate, tin oleate, tin naphthoate, butyltin tri-2-ethylhexylhexoate, tin butyrate, di-octyltin di-decyl mercaptide, bis(neodecanoyloxy)di-octylstannane, or dimethylbis(oleoyloxy)stannane. In a preferred embodiment, the moisture cure catalyst is selected from the group 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 composition according to the present invention, the moisture cure catalyst is present in an amount of 0.1 to 5% by weight, based on the total weight of the composition.

[0047] However, environmental regulatory agencies and directives are increasing or are expected to increase 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 with a reproductive IB classification. Dibutyltin-containing compositions are proposed to be completely eliminated from consumer use over the next three to five years. The use of alternative organotin compounds, such as dioctyltin and dimethyltin compounds, can only be considered a short-term remedy, as these organotin compounds may also be restricted in the future. It would be beneficial to identify non-tin compounds that accelerate the condensation cure of moisture-curing polyacrylate compositions. Examples of non-toxic alternatives to organotin catalysts include titanium isopropoxide, zirconium octanoate, iron octanoate, zinc octanoate, cobalt naphthonate, 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 amino acid compound that is an N-substituted amino acid having at least one non-hydrogen group attached to the N-terminus. In another embodiment, the present invention may include a curable composition employing an amino acid compound as a condensation accelerator, which is an O-substituted amino acid containing a non-hydrogen group attached to the O-terminus. Other suitable amine catalysts include, for example, amino-functional silanes. The non-toxic moisture cure catalyst is employed in an amount sufficient to effect moisture cure, generally from about 0.05% to about 5.00% by weight, advantageously from about 0.5% to about 2.5% by weight.

[0048] The moisture-curable composition of the present invention may further comprise one or more crosslinkers. The crosslinker may be a hexafunctional silane, although other crosslinkers may also be used. Examples of such crosslinkers include methyltrimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, methyltriacetoxysilane, vinyltriacetoxysilane, methyltris(N-methylbenzamido)silane, methyltris(isopropenoxy)silane, methyltris(cyclohexylamino)silane, methyltris(methylethylketoximino)silane, vinyltris(methylethylketoximino)silane, methyltris-(methylisobutylketoximino)silane, vinyltris-(methylisobutylketoximino)silane, tetrakis-(methylethylketoximino)silane, and the like. tetrakis-(methylisobutylketoximino)silane, tetrakis-(methylamylketoximino)silane, dimethylbis-(methylethylketoximino)silane, methylvinylbis-(methylethylketoximino)silane, methylvinylbis-(methylisobutylketoximino)silane, methylvinylbis-(methylamylketoximino)silane, tetrafunctional alkoxyketoxime silane, tetrafunctional alkoxyketoximino silane, tris- or tetrakis-enoxylan, tris- or tetrakis-lactic acid amide silane, and tris- or tetrakis-lactic acid ester silane.

[0049] Typically, the crosslinker used in the compositions of the present invention is present at about 1 to about 10 weight percent 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 moisture-curable polyacrylate composition used in the composition.

[0050] The preparation of moisture-curable polyacrylate compositions can be carried out by mixing the polyacrylate polymers and compositions of the present invention, fillers, and optionally other components. This mixing process can be carried out in a suitable dispersion unit, such as a high-speed mixer, planetary mixer, or Brabender mixer. In all cases, care must be taken to prevent the mixture from coming into contact with moisture, which may result in undesired curing. Suitable means are well known in the art: mixing under vacuum or in an inert atmosphere or protective gas, and drying / heating the individual components before addition.

[0051] The moisture-curable composition can optionally further comprise a silane adhesion promoter, a functional polymer and / or an oligomeric adhesion promoter. The adhesion promoter can act to enhance the adhesive properties of the curable polyacrylate composition to certain substrates (i.e., metal, glass, plastic, ceramic, and mixtures thereof). Any suitable adhesion promoter can be employed for such purposes, depending on the specific substrate components employed in a given application. Examples of useful silane adhesion promoters include, but are not limited to, C3-C24 alkyltrialkoxysilane, (meth)acryloxypropyltrialkoxysilane, chloropropylmethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrismethoxyethoxysilane, vinylbenzylpropyltrimethoxysilane, aminopropyltrimethoxysilane, vinyltriacetoxysilane, glycidoxypropyltrialkoxysilane, β.-(3,4-Epoxycyclohexyl)ethyltrimethoxysilane, mercaptopropylmethoxysilane, 3-aminopropyltriethoxysilane, aminomethyltrimethoxysilane, aminomethyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, (N-2-aminoethyl)-3-aminopropyltrimethoxysilane, (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-di Examples of suitable silanes include (methylamino)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. Particularly preferred are 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.

[0052] The adhesion promoter will typically be used in an amount of from 0.2 to 40% by weight, more preferably from 1 to 20% by weight, based on the total curable polyacrylate composition.

[0053] An effective amount of plasticizer can be added to the compositions of the present invention to ensure the desired workability of the uncured composition and the performance of the final cured composition. 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 can impart additional oil resistance to the cured elastomer. Therefore, 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.

[0054] To enhance the shelf-life stability of the moisture-curable polyacrylate composition, an acid scavenger may be added to remove any acid impurities, such as acrylic acid, from the acrylic monomer. Examples of acid scavengers include hexamethyldisilazane, ethylene oxide, sodium bicarbonate, sodium carbonate, calcium carbonate, magnesium oxide, or combinations thereof.

[0055] The moisture-curable compositions of the present invention may also contain other additives, such as conventional additives such as pigments, inhibitors, deodorizers, etc., so long as they do not interfere with the cure mechanism or its intended use.

[0056] The reaction products of the moisture-curable compositions of the present invention are useful as adhesives or sealants for bonding, sealing, and encapsulating metal surfaces that are exposed to oil during their intended use. The moisture-curable polyacrylate compositions of the present invention can also be formed into a variety of different structural shapes and then addition-cured. Articles formed in this manner are useful in a variety of industries where oil-resistant polyacrylate-based elastomeric articles are required. In the vehicle assembly industry, for example, O-rings, hoses, seals, and gaskets can be formed from the compositions of the present invention. Other conventional applications requiring not only oil resistance but also good sealing properties are also contemplated for the moisture-curable compositions of the present invention.

[0057] Yet another aspect of the present invention relates to methods of making polyacrylate adhesives and sealants using the moisture-curable polyacrylate compositions. The polyacrylate adhesive or sealant composition comprises the polyacrylate polymer of the present invention and a filler.

[0058] In one aspect of the present invention, a method is provided for applying a curable, moisture-curing polyacrylate composition to a surface that will be exposed to oil during its intended use. The surface to which the composition of the present invention is applied can 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 can be composed of a variety of materials, including most metals, glass, and commercial or engineering plastics. In yet another aspect of the present invention, a method is provided for using an oil-resistant mechanical seal that remains sealed even after exposure to oil. The method includes applying a seal-forming amount of the composition as described above to the surface of a machine component. Thereafter, a seal is formed between at least two machine surfaces by addition curing via exposure to elevated temperatures, e.g., 150°C, and the seal then maintains sufficient performance even when exposed to oil under extreme temperature conditions for extended periods of time, e.g., 500 hours or more, or even 1000 hours or more.

[0059] In yet another aspect of the present invention, there is provided 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. Regarding a second embodiment of the present invention, there is provided a method for improving the oil resistance of such a polyacrylate sealant composition. The method comprises the steps of: (a) providing a polyacrylate 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 polyacrylate sealant to form an oil-resistant elastomeric article. Desirably, the sealant composition comprises about 10 to about 90 weight percent polyacrylate polymer, about 1 to about 20 weight percent fumed silica, about 5 to about 50 weight percent precipitated calcium carbonate and / or magnesium oxide, about 1 to about 10 weight percent crosslinker, and about 0.05 to about 5 weight percent moisture cure catalyst (each based on the weight of the total composition). The sealant composition can also include other optional ingredients, including, for example, plasticizers, adhesion promoters, pigments, etc. [Example]

[0060] The following examples are offered for illustrative purposes only and are not intended to be unnecessarily limiting.

[0061] Butyl acrylate (BA), ethyl acrylate (EA), 2,2'-azobis-(2-methylpropionitrile) (AIBN), isopropanol (IPA), ethyl acetate, and dibutyltin dilaurate (DBDTL) are available from Sigma-Aldrich.

[0062] t-Amyl peroxypivalate (t-APP, 75%, 0.5 g) is available from Akzo Nobel.

[0063] Methacryloxypropyltrimethoxysilane (MATMS), and vinyltrimethoxysilane are available from Gelest Inc.

[0064] SF105F engine oil is available from the Testing and Monitoring Center.

[0065] All fillers and additives are commercially available from a variety of suppliers.

[0066] Skin-over time measurements were taken according to ASTM 725: Tack-free time was measured under standard climatic conditions (25±2°C, 50±5% relative humidity). The sample was applied to paper and spread with a putty knife into a skin (approximately 2 mm thick, approximately 7 cm wide). A stopwatch was immediately started. The surface was lightly touched with a fingertip until no more composition remained on the fingertip. The tack-free time was recorded in hours.

[0067] The elongation at break and tensile stress (E modulus) were measured using a tensile tester in accordance with ASTM 708. Sample dumbbell specimens with the following dimensions were used: thickness: 2 ± 0.2 mm; gauge width: 10 ± 0.5 mm; gauge length: approximately 45 mm; total length: 9 cm. Tests were performed after 7 days of curing. A 2 mm-thick film was drawn from the material. This film was stored under standard climatic conditions for 7 days, and dumbbells were then punched out. Three dumbbells were prepared for each test. Tests were performed under standard climatic conditions. The specimens were acclimatized (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, this was at both ends and the center within 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 tensile tester, with the largest possible surface gripped without clamping the narrowest part. The dumbbell was pulled at a test speed of 50 mm / min to a preload of <0.1 MPa.

[0068] A Rheometrics Dynamic Mechanical Analyzer (Model RDA 700) was used to obtain modulus (G'), loss modulus (G''), and tan delta versus temperature sweeps. The instrument was controlled by Rhios software version 4.3.2. Parallel plates, 8 mm in diameter and separated by a gap of approximately 2 mm, were used. After loading the sample, they were cooled to approximately -100°C and the time program was initiated. The program test involved increasing the temperature in 5°C intervals, followed by a 10-second soak time at each temperature. The convection oven was continuously flushed with nitrogen. The frequency was maintained at 10 rad / s. The initial strain at the start of the test was 0.05% (at the outer edge of the plate). To maintain accurately measurable torque throughout the test, the software's auto-strain option was used. This option was set to a maximum applied strain of 80% allowed by the software. The auto-strain adjustment program adjusted the strain at each temperature increment, as needed, using the following procedure: For torques below 200 g-cm, strain increased by 25% of its current value. For torques above 1200 g-cm, strain decreased by 25% of its current value. For torques between 200 g-cm and 1200 g-cm, there was no change in strain at that temperature increment. The shear storage or elastic modulus (G') and shear loss modulus (G'') were calculated by the software from the torque and strain data. The ratio of G'' / G' (also known as tan delta) was also calculated. The Tg of the soft block was taken as the maximum value of tan delta. The flow temperature was reported as the temperature at which the elastic and loss modulus values ​​were equal: G'' = G'.

[0069] Examples 1-8: Preparation of Moisture-Curable Polyacrylate Compositions

[0070] Acrylic polymers (Examples 1 to 8) were prepared in a similar manner, and their monomer compositions and polymer properties are shown in Table 1.

[0071] Example 7 was prepared as follows: A four-neck 500 mL round-bottom reaction flask was equipped with a temperature controller, condenser, overhead mechanical stirrer, two addition funnels, and a nitrogen inlet / outlet. The setup was purged with nitrogen gas for 15 minutes. One of the addition funnels was charged with a monomer mixture of butyl acrylate (165.0 g), ethyl acrylate (132.0 g), and methacryloxypropyltrimethoxysilane (MATMS, 3.0 g). Another funnel was charged with an initiator solution of 2,2'-azobis-(2-methylpropionitrile) (AIBN, 0.18 g) and isopropanol (IPA, 45 g). The reaction flask was charged with the initiator 2,2'-azobis-(2-methylpropionitrile) (AIBN, 0.02 g) and IPA (30 g). The reaction flask was heated to reflux and held for 15 minutes. The monomer mixture in the funnel was then added continuously at a constant rate over 2 hours. Simultaneously, the initiator solution in the funnel was added continuously at a constant rate over 3 hours. After complete addition, the mixture was stirred at reflux for an additional hour. A monomer scavenger solution of t-amyl peroxypivalate (t-APP, 75%, 0.5 g) and IPA (20 g) was charged to the initiator funnel and added to the reaction mixture over 1 hour, followed by an additional hour at reflux. The reaction solvent and volatiles were removed under vacuum at reflux. The resulting polyacrylate polymer was cooled to room temperature under nitrogen. The moisture scavenger vinyltrimethoxysilane (0.1 ppm) was added and mixed for 30 minutes. The final polyacrylate polymer had a weight average molecular weight (M) measured by GPC. w ) was 30,500 and PDI was 2.9.

[0072] [Table 1]

[0073] Example 1(C), prepared using 100 g of ethyl acetate as the solvent, yielded a polymer with high molecular weight and high viscosity. On the other hand, Example 2(C), prepared using 100 g of isopropanol as the solvent, yielded a polymer with low molecular weight and low viscosity. Blending the two solvents produced a polymer with high Mw and high viscosity, as in Example 3(C). Reducing the isopropanol content, as shown in Examples 4-8 in Table 1, yielded acceptable Mw and viscosity for the present application, with high polymer solids, easy solvent recycling, and improved process efficiency. Figure 1 shows frequency sweep tests of the polymer at 25°C and 60°C, showing the results for 10 -1 ~10 1 All polymers maintain a constant viscosity over the frequency range of rad / s.

[0074] [Table 2]

[0075] Example 1(C) was an unstable polymer and gelled over time without the addition of DBDTL. On the other hand, Example 2(C) did not cure even with the addition of DBDTL. Example 3(C) cured too quickly in the presence of DBDTL. Examples 4-8 all exhibited good and manageable cure rates for the present application. As shown in Table 2 and Figure 2, the polymer modulus G' increased with increasing amounts of the moisture-reactive monomer MATMS in the polymer composition. The glass transition temperature Tg was primarily determined by the ratio of the main monomers BA and EA. With less MATMS, the polymer exhibited higher tensile elongation.

[0076] Example 9 77 parts of the polymer from Example 3(C) were mixed with 9 parts precipitated chalk and 1.3 parts carbon black. 3 parts of highly treated hydrophobic silica Aerosil 812S were then added. After thorough mixing under vacuum, 0.5 parts vinyltrimethoxysilane and 0.5 parts aminopropyltrimethoxysilane were added as adhesion promoters. A combination of 0.35 parts tetramethylguanidine and 0.35 parts moisture-cure tin catalyst (DBDTL) was added under anhydrous conditions. The entire mixture was mixed at room temperature and stored in a moisture-free environment.

[0077] Example 10 55 parts of the polymer from Example 6 were mixed with 21 parts ground chalk, 7.5 parts precipitated chalk, and 1 part carbon black. 1.5 parts of highly treated hydrophobic silica Aerosil 812S were then added. After thorough mixing under vacuum, 1 part vinyltrimethoxysilane and 0.5 parts aminopropyltrimethoxysilane were added as adhesion promoters. A combination of 0.25 parts tetramethylguanidine and 0.25 parts moisture-cure tin catalyst was added under anhydrous conditions. The whole was mixed at room temperature and stored in a moisture-free environment.

[0078] Example 11 60 parts of the polymer from Example 8 were mixed with 24 parts ground chalk, 8 parts precipitated chalk, and 1 part carbon black. Then, 1.5 parts of Aerosil 812S, a highly treated hydrophobic silica, were added. After thorough mixing under vacuum, 1.2 parts vinyltrimethoxysilane and 0.6 parts aminopropyltrimethoxysilane were added as adhesion promoters. A combination of 0.25 parts titanium acetylacetonate and 0.25 parts titanium alkoxy moisture cure catalyst was added under anhydrous conditions. The whole was mixed at room temperature and stored in a moisture-free environment.

[0079] [Table 3]

[0080] Examples 9-11 were cured in the presence of a moisture cure catalyst. After curing in air at 25°C and 50% RH for one week, specimens of the fully cured compositions were aged by immersion in SF-105 engine oil at 150°C for one month. The specimens were then removed from the oil and examined for deterioration, including loss of integrity, shape, and partial or complete dissolution in the engine oil. Only specimens that survived 1000 hours were further tested for elongation and tensile properties. Example 9, prepared with Example 3(C) polymer, cured too quickly, but its high Mw and low MATMS content resulted in low crosslink density and good elongation. Example 10, prepared with Example 6 polymer, exhibited high tensile strength, but its high MATMS content resulted in high crosslink density and low elongation. Example 11's low MATMS content improved elongation. Examples 10 and 11 exhibited good cure rates; i.e., they had longer and more workable time before curing. Overall, both Examples 10 and 11 had a good compromise of properties.

[0081] It will be apparent to those skilled in the art that many modifications and variations can be made in this invention without departing from its spirit and scope. The specific embodiments described herein are offered by way of example only, and the 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. 20 to 70 wt. % of n-butyl acrylate; ii. 20 to 70 wt. % ethyl acrylate, and iii. 0.1 to 10 wt. % CH ２ =CR １ COOR ４ SiR ５ ３－ｎ Y ｎ (In the formula, R １ is H or CH ３ ;R ４ is a C1-24 linear, branched or cyclic alkylene or arylene chain; R ５ is a C1-24 linear, branched or cyclic alkyl chain; Y is a C1-3 alkoxy; n=1, 2 or 3. prepared from a monomer consisting of A moisture-curable polyacrylate polymer having a weight average molecular weight (Mw) of 30,000 g / mol to 33,000 g / mol and a PDI of 2.5 to 3.

2. 2. The moisture-curable polyacrylate polymer of claim 1, wherein (iii) the silane-functional acrylic or methacrylic acid derivative is trimethoxysilylpropyl (meth)acrylate, triethoxysilylpropyl (meth)acrylate, trimethoxysilylethyl (meth)acrylate, methyldimethoxysilylpropyl (meth)acrylate, or a combination thereof.

3. 1) A moisture-curable polyacrylate polymer having a weight average molecular weight (Mw) of 30,000 g / mol to 33,000 g / mol and a PDI of 2.5 to 3, prepared from 10 to 90% by weight of monomers consisting of: i. 20 to 70 wt. % of n-butyl acrylate; ii. 20 to 70 wt. % ethyl acrylate, and iii. 0.1 to 10 wt. % CH ２ =CR １ COOR ４ SiR ５ ３－ｎ Y ｎ (In the formula, R １ is H or CH ３ ;R ４ is a C1-24 linear, branched or cyclic alkylene or arylene chain; R ５ is a C1-24 straight, branched or cyclic alkyl chain; Y is a C1-3 alkoxy; n=1, 2 or 3; 2) 5-90% finely divided inorganic filler or mixture of fillers; 3) 0.001 to 0.5 wt. % of a moisture or acid scavenger, or a combination thereof; 4) 0.001 to 5 wt. % of a moisture cure catalyst; and 5) Optionally, up to 10% by weight of crosslinkers, adhesion promoters, plasticizers, acid scavengers, pigments, inhibitors, and / or deodorizers. A moisture-curable composition comprising:

4. 4. The moisture-curable composition of claim 3, wherein the filler is selected from the group consisting of fumed silica, clay, metal salts of carbonates, sulfates, phosphates, carbon black, metal oxides, quartz, zirconium silicate, gypsum, silicon nitride, boron nitride, zeolites, glass, and combinations thereof.

5. 4. The moisture-curable composition of claim 3, wherein the filler is selected from the group consisting of a combination of fumed silica, calcium carbonate, and magnesium oxide.

6. 4. The moisture-curable composition of claim 3, wherein the filler is selected from the group consisting of silicone resins, organic fillers, plastic powders, and combinations thereof.

7. 4. The moisture-curable composition of claim 3, wherein the moisture scavenger is vinyltrimethoxysilane, vinylmethyldimethoxysilane, hexamethyldisilazane, methyltriethoxysilane, methyltrimethoxysilane, or a combination thereof.

8. 4. The moisture-curable composition of claim 3, wherein the acid scavenger is hexamethyldisilazane, ethylene oxide, sodium bicarbonate, sodium carbonate, calcium carbonate, magnesium oxide, or a combination thereof.

9. 4. The moisture-curable composition of claim 3, wherein the moisture-cure catalyst is an organometallic compound of tin, titanium, zinc, zirconium, lead, iron cobalt, antimony, manganese, and bismuth, or an amine, amidine, guanidine, or combinations thereof.

10. 4. The moisture-curable composition of claim 3, wherein the adhesion promoter is a moisture-reactive silane.

11. 11. The moisture-curable composition of claim 10, wherein the moisture-reactive silane is selected from the group consisting of alkoxysilanes, acetoxysilanes, enoxysilanes, oximinosilanes, aminosilanes, lactate ester silanes, lactamide silanes, and combinations thereof.

12. 12. The moisture-curable composition of claim 11, wherein the moisture-reactive silane comprises vinyltrioxyiminosilane, vinyltrialkoxysilane, and combinations thereof.

13. 4. The moisture-curable composition of claim 3, wherein the adhesion promoter is selected from the group consisting of tris(3-(trimethoxysilyl)propyl)isocyanurate, γ-ureidopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, and combinations thereof.

14. A cured composition of the moisture-curable composition of claim 3.

15. 15. The cured composition of claim 14 which is an automotive gasket.

16. 1. A method for preparing a moisture-curable polyacrylate polymer, comprising the steps of: 1) Polymerizing the following for 4 to 24 hours at a reaction temperature of 50 to 120°C: a. A mixture consisting of 40 to 90% by weight of the following monomers: i. 20 to 70 wt. % of n-butyl acrylate; ii. 20 to 70 wt. % ethyl acrylate, and iii. 0.1 to 10 wt. % CH ２ =CR １ COOR ４ SiR ５ ３－ｎ Y ｎ (In the formula, R １ is H or CH ３ ;R ４ is a C1-24 linear, branched or cyclic alkylene or arylene chain; R ５ is a C1-24 straight, branched or cyclic alkyl chain; Y is a C1-3 alkoxy; n=1, 2 or 3; b. 10 to 60% by weight of a compound of the formula HOR ６ (In the formula, R ６ is C １－４ ) alcohols, c. 0 to 60% by weight of a compound of formula R ７ COOR ８ (In the formula, R ７ and R ８ is independently C １－４ an alkyl chain; d. 0.01 to 5% of an azo or peroxide radical initiator; 2) Removal of solvent and volatile materials under vacuum of 10-30 psi at a temperature of 50-120°C. wherein the resulting polyacrylate polymer has a weight average molecular weight (Mw) of 30,000 g / mol to 33,000 g / mol and a PDI of 2.5 to 3.

17. 17. The method of preparing a moisture-curable polyacrylate polymer of claim 16, wherein the alcohol is isopropanol.

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