Curable silicone compositions with water / glycol resistance

Abstract

The invention relates to curable compositions based on polyorganosiloxanes, a special silane crosslinker, an aminosilane, a curing catalyst, and an alkenyl-functional alkoxysilane. The compositions exhibit excellent water / glycol resistance. The invention relates furthermore to the use thereof.

Description

[0001] Henkel AG & Co. KGaA

[0002] Kim / CL

[0003] Curable silicone compositions with water / glycol resistance

[0004] The invention relates to curable compositions based on polyorganosiloxanes, a special silane crosslinker, an aminosilane, a curing catalyst, and an alkenyl-functional alkoxysilane. The compositions exhibit excellent water / glycol resistance. The invention relates furthermore to the use thereof.

[0005] Polymer systems which possess reactive crosslinkable silyl groups, for example alkoxysilyl groups, have long been known. In the presence of atmospheric moisture these alkoxysilane-terminated polymers are able to condense with elimination of the alkoxy groups. Depending on the amount of alkoxysilane groups and their structure, mainly long-chain polymers (thermoplastics), relatively wide-meshed three-dimensional networks (elastomers) or highly crosslinked systems (thermosets) form.

[0006] Silicone polymers (polyorganosiloxanes), particularly polydialkylsiloxanes such as polydimethylsiloxane (PDMS), have great importance in the production of adhesive, sealing, coating, and insulation materials. Among these, those that vulcanize at low temperatures and under ambient conditions constitute a significant share of the market. Typical formulations contain a reactive polyorganosiloxane, in particular a silanol-terminated polyorganosiloxane having at least one, preferably two hydroxy groups bound to a silicon atom. It is typically used in combination with a silane-based crosslinker which has hydrolyzable groups bound to the silicon atom. While the polyorganosiloxane and crosslinker can be present as separate components, both can also be reacted with each other to form a modified polyorganosiloxane which can then be used in a curable composition. The term endcapping (end group capping) is also used in this regard. This can be carried out optionally in the presence of a catalyst, whereby the catalyst is used to mediate the endcapping selectively without simultaneously curing the polyorganosiloxane.

[0007] The uses and possible applications of such silane-terminated polymer systems are equally diverse. They can, for example, be used for the production of elastomers, sealants, adhesives, elastic adhesive systems, rigid and flexible foams, a wide variety of coating systems and in the medical field, for example, for impression materials in dentistry. These products can be applied in any form, such as painting, spraying, casting, pressing, filling and the like.

[0008] Numerous crosslinkers that act as endcapping or functionalizing moieties for the respective polymer backbone are known in the art. Besides their functionality used for coupling to the polymer backbone, these can be differentiated into acidic, basic, and neutral crosslinkers based on the type of leaving groups released during hydrolysis. Typical acidic crosslinkers contain acid groups as hydrolyzable groups and release the corresponding acids, e.g., acetic acid, during the crosslinking. Typical basic crosslinkers release amines during the crosslinking. In both cases, aggressive compounds are released during the crosslinking, which can corrode or break down, e.g., metals, stone, or mortar, and which moreover have an intense, often unpleasant odor. Neutral crosslinkers are therefore often used formodern curable silicone compositions. Typical representatives of neutral crosslinkers have hydrolyzable groups, which release alcohols or oximes during the crosslinking, such as methanol or ethanol.

[0009] Such alkoxy systems nevertheless have the disadvantage that multiple problems arise in the case of the storage stability of relevant curable compositions and the cured products exhibit only poor adhesion to some materials. Oximosilane crosslinkers, which hydrolyze with the release of an alkanone oxime, usually do not have these disadvantages and are therefore widely used. The most common representative of the oximosilane crosslinkers releases butan-2-one oxime upon crosslinking. This compound is however suspected of causing cancer so that there is an urgent need for alternative neutral crosslinkers. Apart from that, the released oximes also have an intense, foul odor and working with curable compositions, which contain such crosslinker, is perceived as disagreeable by the users.

[0010] Silane compounds that release a-hydroxycarboxylic acid esters or a-hydroxycarboxylic acid amides during crosslinking, have already been proposed therefore as alternative crosslinkers.

[0011] The preparation of suitable silane compounds has been long known and is described, for example, by M. M. Sprung in “Some a-carbalkoxyalkoxysilanes,” J. Org. Chem., 1958, 23 (10), pp. 1530-1534.

[0012] DE 32 10 337 A1 as well discloses relevant silane compounds and the preparation and use thereof in curable compositions based on polydiorganosiloxanes, which have condensable end groups.

[0013] Hardeners for silicone rubber materials, which have three 2-hydroxypropionic acid alkyl ester groups, i.e., lactic acid alkyl ester groups, are known from EP 2 030 976 A1. Vinyl tris(ethyl lactato)silane is particularly preferred in this case.

[0014] EP 2 774 672 A1 describes special catalysts for the crosslinking of silicone rubber materials with a crosslinker based on a silane compound with lactate groups. Then again, the crosslinker can be the compounds known from EP 2 030 976 A1.

[0015] EP 3271 421 A1 describes curable compositions comprising at least one polyorganosiloxane, at least one silane compound with lactate groups, at least one aminosilane and tin compound with a special molar ratio.

[0016] Although the use of a crosslinker based on a silane compound with lactate groups or similar a-carbalkoxyalkoxy groups is associated with many advantages, there is still a need for a neutral sealant system which exhibits excellent water / glycol resistance which is required for flexible sealing, e.g., for flange sealing.

[0017] The present invention achieves said object by providing curable compositions comprising at least one polyorganosiloxane, at least one special silane crosslinker, at least one aminosilane, at least one curing catalyst, and at least one alkenyl-functional alkoxysilane.It has been found that the combination according to the invention provides for excellent water / glycol resistance while retaining good curing and adhesion properties.

[0018] In a first aspect, the present invention therefore relates to a curable composition comprising or consisting essentially of:

[0019] (A) at least one polyorganosiloxane, which has at least one hydroxy group bound to a silicon atom, (B) at least one silane of the formula (1):

[0020] Si(R1)m(R2)n(R3)4-(m+n) (1)

[0021] wherein

[0022] each R1independently stands for:

[0023] a substituted or unsubstituted alkyl, alkenyl, or alkynyl group;

[0024] a substituted or unsubstituted cycloaliphatic group or aryl group;

[0025] a substituted or unsubstituted heteroalicyclic group or heteroaryl group;

[0026] each R2independently stands for a group of the general formula (2):

[0027] -OCR42COOR5(2)

[0028] wherein

[0029] each R4independently stands for:

[0030] hydrogen; or

[0031] a substituted or unsubstituted alkyl, alkenyl, or alkynyl group;

[0032] R5stands for:

[0033] a substituted or unsubstituted alkyl, alkenyl, or alkynyl group;

[0034] each R3independently stands for a group of the general formula (3):

[0035] -OCR62CONR7R8(3)

[0036] wherein

[0037] each R6independently stands for:

[0038] hydrogen or

[0039] a substituted or unsubstituted alkyl, alkenyl, or alkynyl group;

[0040] R7stands for:

[0041] hydrogen,

[0042] a substituted or unsubstituted alkyl, alkenyl, or alkynyl group,

[0043] a substituted or unsubstituted cycloaliphatic group or aryl group,

[0044] R8, ora group -(CH2)P-COOR9, wherein p is an integer from 2 to 10, particularly 2, and R9stands for a substituted or unsubstituted alkyl, alkenyl, or alkynyl group, or a substituted or unsubstituted cycloaliphatic group or aryl group;

[0045] R8stands for a group of the general formula (4):

[0046] -R10-SiR11o(OR12)3-o (4)

[0047] wherein

[0048] R10stands for:

[0049] an alkylene group, optionally interrupted by a heteroatom;

[0050] each R11independently stands for:

[0051] a substituted or unsubstituted alkyl, alkenyl, or alkynyl group;

[0052] each R12independently stands for:

[0053] a substituted or unsubstituted alkyl, alkenyl, or alkynyl group,

[0054] an acyl group,

[0055] or a group of the formula (5):

[0056] -CR132COOR14(5)

[0057] wherein

[0058] each R13independently stands for:

[0059] hydrogen; or

[0060] a substituted or unsubstituted alkyl, alkenyl, or alkynyl group;

[0061] R14stands for:

[0062] a substituted or unsubstituted alkyl, alkenyl, or alkynyl group; and

[0063] o independently stands for 0, 1 , or 2, and

[0064] m independently stands for 0 or 1 and n independently stands for 1 , 2, 3, or 4, whereby the sum n + m is a maximum of 4,

[0065] (C) at least one aminosilane,

[0066] (D) at least one curing catalyst, and

[0067] (E) at least one alkenyl-functional alkoxysilane.

[0068] The invention further relates to the use of a curable composition of the invention ora curable composition prepared according to the method of the invention as an adhesive, sealing, or coating material.

[0069] A “curable composition” is understood to be a substance or mixture of multiple substances, which is curable by physical or chemical measures. In this regard, these chemical or physical measures can be, for example, the supplying of energy in the form of heat, light, or other electromagnetic radiation, butalso simply bringing into contact with atmospheric moisture, water, or a reactive component. The composition thereby changes from an original state to a state that has a higher hardness. In the context of the present invention, “curable” predominantly relates to the property of the terminal silane groups of formula (I) to condensate.

[0070] Provided reference is made to molecular weights of oligomers or polymers in the present application, the quantities, unless otherwise stated, refer to the weight average, i.e., the Mwvalue, and not to the number average molecular weight. The molecular weight is determined by gel permeation chromatography (GPC) with tetrahydrofuran (THF) as the eluent according to DIN 55672-1 :2007-08, preferably at 35°C. Molecular weights of monomeric compounds are calculated based on the respective molecular formula and the known molecular weights of the individual atoms.

[0071] “At least one,” as used herein, refers to 1 or more, i.e., 1 , 2, 3, 4, 5, 6, 7, 8, 9, or more. In regard to an ingredient, the term relates to the type of ingredient and not to the absolute number of molecules. “At least one polymer” thus means, for example, at least one type of polymer, i.e., that a type of polymer or a mixture of a number of different polymers can be used. Together with weight data, the term refers to all compounds ofthe given type, contained in the composition / mixture, i.e., that the composition contains no other compounds of this type beyond the given amount ofthe relevant compounds.

[0072] All percentage data, provided in connection with the compositions described herein, referto % by weight, based in each case on the relevant mixture, unless explicitly indicated otherwise.

[0073] “Consisting essentially of’, as used herein, means that the respective composition is composed mainly, i.e. by at least 50% by weight, for example at least 60, 70 or 80 %, ofthe listed components (A), (B) and (C) and optionally fillers and / or plasticizers, as described below.

[0074] “Alkyl,” as used herein, refers to a saturated aliphatic hydrocarbon including straight-chain and branched-chain groups. The alkyl group preferably has 1 to 10 carbon atoms (if a numerical range, e.g., “1 -10” is given herein, this means that this group, in this case the alkyl group, can have 1 carbon atom, 2 carbon atoms, 3 carbon atoms, etc., up to and including 10 carbon atoms). In particular, the alkyl can be an intermediate alkyl, which has 5 to 6 carbon atoms, or a lower alkyl, which has 1 to 4 carbon atoms, e.g., methyl, ethyl, n-propyl, isopropyl, butyl, isobutyl, tert-butyl, etc. The alkyl groups can be substituted or unsubstituted. “Substituted,” as used in this connection, means that one or more carbon atoms and / or hydrogen atom(s) ofthe alkyl group are replaced by heteroatoms or functional groups. Functional groups that can replace the hydrogen atoms are selected particularly from =O, =S, -OH, -SH, -NH2 -NO2, -CN, -F, -Cl, -Br, -I, -COOH, -CONH2, -OCN, -NCO, C3-8 cycloalkyl, Ce-14 aryl, a 5-10-membered heteroaryl ring, in which 1 to 4 ring atoms independently are nitrogen, oxygen, or sulfur, and a 5-10-membered heteroalicyclic ring, in which 1 to 3 ring atoms are independently nitrogen, oxygen, or sulfur. Substituted alkyl includes, for example, alkylaryl groups. Heteroalkyl groups in which 1 or more carbon atoms are replaced by heteroatoms, particularly selected from O, S, N, or Si, are obtained by the replacement of one or more carbon atoms by heteroatoms. Examples of such heteroalkyl groups are, without limitation,methoxymethyl, ethoxyethyl, propoxypropyl, methoxyethyl, isopentoxypropyl, ethylaminoethyl, trimethoxypropylsilyl, etc.

[0075] “Alkenyl,” as used herein, refers to an alkyl group, as defined herein, which consists of at least two carbon atoms and at least one carbon-carbon double bond, e.g., ethenyl, propenyl, butenyl, or pentenyl and structural isomers thereof such as 1 - or 2-propenyl, 1 -, 2-, or 3-butenyl, etc. Alkenyl groups can be substituted or unsubstituted. If they are substituted, the substituents are as defined above for alkyl.

[0076] “Alkenyloxy” refers to an alkenyl group, as defined herein, that is linked via an -O- to the rest of the molecule. The respective term thus includes enoxy groups, such as vinyloxy (H2C=CH-O-).

[0077] “Alkynyl,” as used herein, refers to an alkyl group, as defined herein, which consists of at least two carbon atoms and at least one carbon-carbon triple bond, e.g., ethynyl (acetylene), propynyl, butynyl, or petynyl and structural isomers thereof as described above. Alkynyl groups can be substituted or unsubstituted. If they are substituted, the substituents are as defined above for alkyl. “Alkylnyloxy” refers to an alkynyl group, as defined herein, that is linked via an -O- to the rest of the molecule.

[0078] A “cycloaliphatic group” or “cycloalkyl group,” as used herein, refers to monocyclic or polycyclic groups (a number of rings with carbon atoms in common), particularly of 3-8 carbon atoms, in which the ring does not have a completely conjugated pi-electron system, e.g., cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, etc. Cycloalkyl groups can be substituted or unsubstituted. “Substituted,” as used in this regard, means that one or more hydrogen atoms of the cycloalkyl group are replaced by functional groups. Functional groups that can replace the hydrogen atoms are selected particularly from =O, =S, -OH, -SH, -NH2, -NO2, -CN, -F, -Cl, -Br, -I, -COOH, -CONH2, -OCN, -NCO, C1-10 alkyl, C2-10 alkenyl, C2-10 alkynyl, C3-8 cycloalkyl, Ce-14 aryl, a 5-10-membered heteroaryl ring, in which 1 to 4 ring atoms independently are nitrogen, oxygen, or sulfur, and a 5-10-membered heteroalicyclic ring, in which 1 to 3 ring atoms independently are nitrogen, oxygen, or sulfur. “Cycloalkyloxy” refers to a cycloalkyl group, as defined herein, that is linked via an -O- to the rest of the molecule.

[0079] “Aryl,” as used herein, refers to monocyclic or polycyclic groups (i.e., rings that have neighboring carbon atoms in common), particularly of 6 to 14 carbon ring atoms which have a completely conjugated pi-electron system. Examples of aryl groups are phenyl, naphthalenyl, and anthracenyl. Aryl groups can be substituted or unsubstituted. If they are substituted, the substituents are as defined above for cycloalkyl. “Aryloxy” refers to an aryl group, as defined herein, that is linked via an -O- to the rest of the molecule.

[0080] A “heteroaryl” group, as used herein, refers to a monocyclic or polycyclic (i.e., rings that share an adjacent ring atom pair) aromatic ring, having particularly 5 to 10 ring atoms, wherein one, two, three, or four ring atoms are nitrogen, oxygen, or sulfur and the rest is carbon. Examples of heteroaryl groupsare pyridyl, pyrrolyl, furyl, thienyl, imidazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyrazolyl, 1 ,2,3-triazolyl, 1 ,2,4-triazolyl, 1 ,2,3-oxadiazolyl, 1 ,2,4-oxadiazolyl, 1 ,2,5-oxadiazolyl, 1 ,3,4-oxadiazolyl, 1 ,3,4-triazinyl, 1 ,2,3-triazinyl, benzofuryl, isobenzofuryl, benzothienyl, benzotriazolyl, isobenzothienyl, indolyl, isoindolyl, 3H-indolyl, benzimidazolyl, benzothiazolyl, benzoxazolyl, quinolizinyl, quinazolinyl, phthalazinyl, quinoxalinyl, cinnolinyl, naphthyridinyl, quinolyl, isoquinolyl, tetrazolyl, 5, 6,7,8-tetrahydroquinolyl, 5,6,7,8-tetrahydroisoquinolyl, purinyl, pteridinyl, pyridinyl, pyrimidinyl, carbazolyl, xanthenyl, or benzoquinolyl. Heteroaryl groups can be substituted or unsubstituted. If they are substituted, the substituents are as defined above for cycloalkyl. “(Hetero)aryl”, as used herein, refers to both aryl and heteroaryl groups as defined herein. “Heteroaryloxy” refers to a heteroaryl group, as defined herein, that is linked via an -O- to the rest of the molecule.

[0081] A “heteroalicyclic group” or a “heterocycloalkyl group,” as used herein, refers to a monocyclic or fused ring having 5 to 10 ring atoms, which contains one, two, or three heteroatoms, selected from N, O, or S, whereby the rest of the ring atoms are carbon. A “heterocycloalkenyl” group contains in addition one or more double bonds. The ring however has no completely conjugated pi-electron system. Examples of heteroalicyclic groups are pyrrolidinone, piperidine, piperazine, morpholine, imidazolidine, tetrahydropyridazine, tetrahydrofuran, thiomorpholine, tetrahydropyridine, and the like. Heterocycloalkyl groups can be substituted or unsubstituted. If they are substituted, the substituents are as defined above for cycloalkyl. “Heteroalicyclic” refers to a heteroalicyclic group, as defined herein, that is linked via an — O- to the rest of the molecule.

[0082] The curable compositions of the invention contain as component (A) at least one polyorganosiloxane, which has at least one hydroxy group bound to a silicon atom. Preferably, the polyorganosiloxane has at least two hydroxy groups bound to a silicon atom. It is preferred, in addition, that the hydroxy group or hydroxy groups are bound to terminal silicon atoms. If the polyorganosiloxane is branched, it preferably has a hydroxy group at each end.

[0083] The polyorganosiloxane, which has at least one hydroxy group bound to a silicon atom, is preferably a polydiorganosiloxane, preferably a polydimethylsiloxane.

[0084] Preferably, therefore, an a,oj-dihydroxy-terminated polydiorganosiloxane, particularly an a, co-di hydroxyterminated polydimethylsiloxane is used as the polyorganosiloxane, which has at least one hydroxy group bound to a silicon atom. Particularly preferred are a,oj-dihydroxy-terminated polydimethylsiloxanes, which have a kinematic viscosity at 25°C of 5000 to 120,000 cSt, particularly 10,000 to 100,000 cSt, and particularly preferably 50,000 to 90,000 cSt.

[0085] The curable compositions contain the at least one polyorganosiloxane, which has at least one hydroxy group bound to a silicon atom, preferably in an amount of 20 to 90% by weight, particularly preferably in an amount of 30 to 50% by weight, based in each case on the total weight of the composition. If a mixture of a number of polyorganosiloxanes is used, the quantitative data naturally relate to the totalamount of the polyorganosiloxanes, which have at least one hydroxy group bound to a silicon atom, in the composition.

[0086] The curable compositions of the invention contain as component (B) at least one silane of the formula (1):

[0087] Si(R1)m(R2)n(R3)4-(m+n) (1),

[0088] wherein.

[0089] In this case, each R1independently stands for a substituted or unsubstituted alkyl, alkenyl, or alkynyl group; a substituted or unsubstituted cycloaliphatic group or aryl group; or a substituted or unsubstituted heteroalicyclic group or heteroaryl group.

[0090] Preferably, each R1independently of one another stands for an alkyl group having 1 to 10 carbon atoms, preferably having 1 to 4 carbon atoms, particularly methyl, ethyl, propyl, or isopropyl, for an alkenyl group having 2 to 10 carbon atoms, preferably 2 to 4 carbon atoms, particularly vinyl or allyl, or an aryl group having 6 to 10 carbon atoms, particularly phenyl.

[0091] Particularly preferably, R1independently of one another stands for methyl, vinyl, or phenyl, very particularly preferably for methyl or vinyl.

[0092] In formula (1), each R2independently of one another stands for a group of the general formula (2):

[0093] -OCR42COOR5(2),

[0094] wherein

[0095] each R4independently stands for:

[0096] hydrogen; or

[0097] a substituted or unsubstituted alkyl, alkenyl, or alkynyl group; and

[0098] R5stands for:

[0099] a substituted or unsubstituted alkyl, alkenyl, or alkynyl group.

[0100] In other words, R2is an a-hydroxycarboxylic acid ester group.

[0101] Preferably each R2independently of one another stands for a group of the formula (2), whereby one of the R4groups stands for hydrogen and the second R4group stands for hydrogen or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, preferably an unsubstituted alkyl group having 1 to 10 carbon atoms, preferably having 1 to 4 carbon atoms, particularly methyl, and R5for a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, preferably an unsubstituted alkyl group having 1 to 10 carbon atoms, preferably having 1 to 4 carbon atoms, particularly preferably methyl or ethyl.Preferably each R2independently of one another stands for a group of the formula (2), whereby one of the R4groups stands for hydrogen and the second R4group stands for methyl, and R5for ethyl.

[0102] In formula (1), each R3independently of one another stands for a group of the general formula (3):

[0103] -OCR62CONR7R8(3).

[0104] In other words, R3is an a-hydroxycarboxylic acid amide group.

[0105] In this case, each R6independently stands for:

[0106] hydrogen or

[0107] a substituted or unsubstituted alkyl, alkenyl, or alkynyl group;

[0108] R7stands for:

[0109] hydrogen,

[0110] a substituted or unsubstituted alkyl, alkenyl, or alkynyl group,

[0111] a substituted or unsubstituted cycloaliphatic group or aryl group,

[0112] R8, or

[0113] a group -(CH2)P-COOR9, wherein p is an integer from 2 to 10, particularly 2, and R9stands for a substituted or unsubstituted alkyl, alkenyl, or alkynyl group, or a substituted or unsubstituted cycloaliphatic group or aryl group;

[0114] R8stands for a group of the general formula (4):

[0115] -R10-SiR11o(OR12)3-o (4)

[0116] wherein

[0117] R10stands for:

[0118] an alkylene group, optionally interrupted by a heteroatom;

[0119] each R11independently stands for:

[0120] a substituted or unsubstituted alkyl, alkenyl, or alkynyl group;

[0121] each R12independently stands for:

[0122] a substituted or unsubstituted alkyl, alkenyl, or alkynyl group,

[0123] an acyl group,

[0124] or a group of the formula (5):

[0125] -CR132COOR14(5)

[0126] wherein

[0127] each R13independently stands for:

[0128] hydrogen; or

[0129] a substituted or unsubstituted alkyl, alkenyl, or alkynyl group;

[0130] R14stands for:

[0131] a substituted or unsubstituted alkyl, alkenyl, or alkynyl group; and

[0132] o independently stands for 0, 1 , or 2, andm independently stands for 0 or 1 and n independently stands for 1 , 2, 3, or 4, whereby the sum n + m is a maximum of 4.

[0133] Preferably, one of the R6groups stands for hydrogen and the second R6group for hydrogen or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, preferably an unsubstituted alkyl group having 1 to 10 carbon atoms, preferably having 1 to 4 carbon atoms, particularly methyl.

[0134] R7preferably stands for hydrogen, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, preferably an unsubstituted alkyl group having 1 to 10 carbon atoms, particularly having 1 to 4 carbon atoms, particularly methyl.

[0135] R10preferably is an alkylene group of the formula -(CH2)P-, wherein p is an integerfrom 1 to 6, particularly 3.

[0136] Each R11independently of one another preferably stands for a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, preferably an unsubstituted alkyl group having 1 to 10 carbon atoms, particularly having 1 to 4 carbon atoms, particularly preferably methyl or ethyl.

[0137] Each R12independently of one another preferably stands for a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, preferably an unsubstituted alkyl group having 1 to 10 carbon atoms, particularly having 1 to 4 carbon atoms, particularly preferably methyl or ethyl.

[0138] Each R13preferably stands for hydrogen or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, preferably an unsubstituted alkyl group having 1 to 10 carbon atoms, preferably having 1 to 4 carbon atoms, particularly methyl. Particularly preferably, one R13group stands for hydrogen and the second R13group for hydrogen or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, preferably an unsubstituted alkyl group having 1 to 10 carbon atoms, preferably having 1 to 4 carbon atoms, particularly methyl.

[0139] R14preferably stands for a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, preferably an unsubstituted alkyl group having 1 to 10 carbon atoms, preferably having 1 to 4 carbon atoms, particularly preferably methyl or ethyl.

[0140] o stands for 0, 1 or 2, preferably for 0 or 1 , particularly preferably for 0.

[0141] Preferably each R3independently of one another stands for a group of the formula (3), whereby one of the R6groups stands for hydrogen and the second R6group for hydrogen or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, preferably an unsubstituted alkyl group having 1 to 10 carbon atoms, preferably having 1 to 4 carbon atoms, particularly methyl, R7for hydrogen, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, preferably an unsubstituted alkylgroup having 1 to 10 carbon atoms, particularly having 1 to 4 carbon atoms, particularly methyl, and R8for a group of the formula (4), whereby R10is an alkylene group of the formula -(CH2)P-, wherein p is an integer from 1 to 6, particularly 3, each R11independently of one another for a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, preferably an unsubstituted alkyl group having 1 to 10 carbon atoms, particularly having 1 to 4 carbon atoms, particularly preferably methyl or ethyl, and each R12independently of one another for a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, preferably an unsubstituted alkyl group having 1 to 10 carbon atoms, particularly having 1 to 4 carbon atoms, particularly preferably methyl or ethyl, and o for 0, 1 , or 2, preferably 0 or 1.

[0142] Particularly preferably each R3independently of one another stands for a group of the formula (3), wherein one of the R6groups stands for hydrogen and the second R6group for methyl, R7for hydrogen or methyl, and R8for a group of the formula (4), wherein R10is an alkylene group of the formula -(CH2)P-, wherein p stands for 3, each R11independently of one another stands for methyl or ethyl, and each R12independently of one another for methyl or ethyl, and o for 0, 1 , or 2, preferably 0 or 1 , particularly preferably 0.

[0143] In a first embodiment, n and m in formula (1) are selected so that the sum n + m is 4. In this case, the silane of the formula (1) contains no R3group, i.e., no a-hydroxycarboxylic acid amide group. Preferred silanes of the formula (1) in this case are selected from the group consisting of methyl tris(ethyl lactato)silane, ethyl tris(ethyl lactato)silane, phenyl tris(ethyl lactato)silane, vinyl tris(ethyl lactato)silane, tetra(ethyl lactato)silane, and mixtures thereof.

[0144] In a second embodiment, n and m in formula (1) are selected so that the sum n + m is 3. In this case, the silane of the formula (1) contains at least one R3group, i.e., at least one a-hydroxycarboxylic acid amide group. Preferred silanes of the formula (1) in this case are selected from compounds, which are obtained by the selective amidation of methyl tris(ethyl lactato)silane, ethyl tris(ethyl lactato)silane, phenyl tris(ethy I lactato)silane, vinyl tris(ethy I lactato)silane, tetra(ethyl lactato)silane, or mixtures thereof with an amine of the formula (7):

[0145] (HR7N)-R10-SiR11o(OR12)3-o (7)

[0146] wherein

[0147] o, R7, R10, and each R11and each R12, in each case independently of one another, have the aforesaid general, preferred, and particularly preferred meanings. Particularly preferably, this concerns an amidation product of methyl tris(ethyl lactato)silane, ethyl tris(ethyl lactato)silane, phenyl tris(ethyl lactato)silane, vinyl tris(ethyl lactato)silane, tetra(ethyl lactato)silane, or mixtures thereof with 3-aminopropyltrimethoxysilane and / or 3-aminopropyltriethoxysilane.

[0148] In preferred embodiments, m is 1 .In preferred embodiments, n is 2, 3 or 4, more preferably 2 or 3, most preferably 3.

[0149] The curable compositions contain the silane of the formula (1) preferably in an amount of 3 to 8% by weight, particularly preferably in an amount of 5 to 7% by weight, based in each case on the total weight of the composition. If a mixture of a number of silanes of the formula (1) is used, the quantitative data naturally refer to the total amount of silanes of the formula (1) in the composition.

[0150] The curable compositions can contain the polyorganosiloxane, which has at least one hydroxy group bound to a silicon atom, and the silane ofthe formula (1) as separate components. It is likewise possible, however, that these components are present in the form of a prepolymer. The prepolymer is a reaction product ofthe two components. Suitable reactions are known and are also called endcapping. This can be carried out optionally in the presence of a catalyst, whereby the catalyst is to mediate the endcapping selectively without simultaneously curing the polyorganosiloxane. Suitable catalysts are, for example, acids, organic lithium compounds, as they are described, for example, in EP 0 564 253 A1 , amines, inorganic oxides, potassium acetate, organotitanium derivatives, titanium / amine combinations, and carboxylic acid / amine combinations.

[0151] If the polyorganosiloxane, which has at least one hydroxy group bound to a silicon atom, and the silane of the formula (1) are present as a prepolymer, thus the aforesaid quantitative data for polyorganosiloxane, on the one hand, and the silane, on the other, for the prepolymer are to be applied additively. The curable compositions, therefore, contain the prepolymer preferably in an amount of 22 to 97% by weight, particularly preferably in an amount of 33 to 55% by weight, based in each case on the total weight of the composition. If a mixture of a number of prepolymers is used, the quantitative data naturally refer to the total amount of prepolymers in the composition.

[0152] The curable compositions contain as component (C) at least one aminosilane.

[0153] Preferably the aminosilane is an aminosilane ofthe formula (6),

[0154] (R15R7N)-R10-SiR11o(OR12)3-o (6)

[0155] wherein

[0156] o, R7, R10, and each R11and each R12, in each case independently of one another, have the aforesaid general, preferred, and particularly preferred meanings, and

[0157] R15stands for:

[0158] hydrogen,

[0159] a substituted or unsubstituted alkyl, alkenyl, or alkynyl group.

[0160] R15preferably stands for hydrogen, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, preferably an unsubstituted alkyl group having 1 to 10 carbon atoms, particularly having 1 to 4 carbon atoms, particularly methyl. Particularly preferably, R15stands for hydrogen or methyl.The aminosilane is preferably selected from the group consisting of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, aminomethyltrimethoxysilane, aminomethyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, (N-2-aminoethyl)-3-aminopropyltrimethoxysilane, (N-2-amino-ethyl)-3-aminopropyltriethoxysilane, diethylenetriaminopropyltrimethoxysilane, phenylaminomethyltrimethoxysilane, (N-2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-(N-phenylamino)propyl-trimethoxysilane, 3-piperazinylpropylmethyldimethoxysilane, 3-(N,N-dimethylaminopropyl)amino-propylmethyldimethoxysilane, tri[(3-triethoxysilyl)propyl]amine, tri[(3-trimethoxysilyl)propyl]amine, and the oligomers thereof, 3-(N,N-dimethylamino)propyltrimethoxysilane, 3-(N,N-dimethylamino)-propyltriethoxysilane, (N,N-dimethylamino)methyltrimethoxysilane, (N,N-dimethylamino)methyl-triethoxysilane, bis(3-trimethoxysilyl)propylamine, bis(3-triethoxysilyl)propylamin, and mixtures thereof, particularly preferably of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, aminomethyltrimethoxysilane, aminomethyltriethoxysilane, 3-(N,N-dimethylamino)propyl-trimethoxysilane, 3-(N,N-dimethylamino)propyltriethoxysilane, (N,N-dimethylamino)methyl-trimethoxysilane, (N,N-dimethylamino)methyltriethoxysilane, bis(3-trimethoxysilyl)propylamine, bis(3-triethoxysilyl)propylamine, and mixtures thereof.

[0161] The curable compositions comprise the aminosilane preferably in an amount of 0.05 to 4% by weight, preferably in an amount of 0.1 to 2% by weight, particularly preferably in an amount of 0.2 to 2% by weight, based in each case on the total weight of the composition. If a mixture of a number of aminosilanes is used, the quantitative data naturally refer to the total amount of aminosilanes in the composition.

[0162] The curable compositions comprise as component (D) at least one curing catalyst.

[0163] In various embodiments, the curing catalyst may be a tin compound, preferably an organotin compound or an inorganic tin salt. Tin in these tin compounds is preferably bivalent or tetravalent. Component (D) is added to the composition particularly as a crosslinking catalyst. Suitable inorganic tin salts are, for example, tin(ll) chloride and tin(IV) chloride. Organotin compounds (tin organyles) are used preferably as the tin compounds, however. Suitable organotin compounds are, for example, the 1 ,3-dicarbonyl compounds of bivalent or tetravalent tin, for example, the acetylacetonates such as di(n-butyl)tin(IV) di(acetylacetonate), di(n-octyl)tin(IV) di(acetylacetonate), (n-octyl)(n-butyl)tin(IV) di(acetylacetonate); the dialkyl tin(IV) dicarboxylates, for example, di-n-butyltin dilaurate, di-n-butyltin maleate, di-n-butyltin diacetate, di-n-octyltin dilaurate, di-n-octyltin diacetate, or the corresponding dialkoxylates, for example, di-n-butyltin dimethoxide; oxides of tetraval ent tin, for example, dialkyltin oxides, such as, for example, di-n-butyltin oxide and di-n-octyltin oxide; and the tin(ll) carboxylates such as tin(ll) octoate or tin(ll) phenolate.

[0164] Suitable furthermore are tin compounds of ethyl silicate, dimethyl maleate, diethyl maleate, dioctyl maleate, dimethyl phthalate, diethyl phthalate, dioctyl phthalate, such as, for example, di(n-butyl)tin(l V) di(methyl maleate), di(n-butyl)tin(l V) di(butyl maleate), di(n-octyl)tin(IV) di(methyl maleate), di(n-octyl)tin(IV) di(butyl maleate), di(n-octyl)tin(IV) di(isooctyl maleate); and di(n-butyl)tin(IV) sulfide, (n-butyl)2Sn(SCH2COO), (n-octyl)2Sn(SCH2COO), (n-octyl)2Sn(SCH2CH2COO), (n-octyl)2Sn(SCH2CH2COOCH2CH2OCOCH2S), (n-butyl)2-Sn(SCH2COO-i-C8Hi7)2, (n-octyl)2Sn(SCH2COO-i-C8Hi7)2, and (n-octyl)2Sn(SCH2COO-n-CsHi7)2.

[0165] Preferably, the tin compound is selected from the group consisting of 1 ,3-dicarbonyl compounds of bivalent or tetravalent tin, the dialkyltin(IV) dicarboxylates, the dialkyltin(IV) dialkoxylates, the dialkyltin(IV) oxides, the tin(ll) carboxylates, and mixtures thereof.

[0166] Particularly preferably, the tin compound is a dialkyltin(IV) dicarboxylate, particularly di-n-butyltin dilaurate or di-n-octyltin dilaurate.

[0167] Additionally or alternatively, other metal-based condensation catalysts may be used, including, without limitation, compounds of titanium such as organotitanates or chelate complexes, cerium compounds, zirconium compounds, molybdenum compounds, manganese compounds, copper compounds, aluminum compounds, or zinc compounds or their salts, alkoxylates, chelate complexes, or catalytically active compounds of the main groups or salts of bismuth, lithium, strontium, or boron.

[0168] Further suitable (tin-free) curing catalysts are, for example, organometallic compounds of iron, particularly the 1 ,3-dicarbonyl compounds of iron such as, e.g., iron(lll) acetylacetonate.

[0169] Boron halides such as boron trifluoride, boron trichloride, boron tribromide, boron triiodide, or mixtures of boron halides can also be used as curing catalysts. Particularly preferred are boron trifluoride complexes such as, e.g., boron trifluoride diethyl etherate, which as liquids are easier to handle than gaseous boron halides.

[0170] Further, amines, nitrogen heterocycles, and guanidine derivatives are suitable in general for catalysis. An especially suitable catalyst from this group is 1 ,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

[0171] Preferably the curing catalyst can be selected from guanidine derivatives.

[0172] Titanium, aluminum, and zirconium compounds, or mixtures of one or more catalysts from one or more of the just mentioned groups may also be used as catalysts.

[0173] Suitable as titanium catalysts are compounds that have hydroxy groups and / or substituted or unsubstituted alkoxy groups, therefore titanium alkoxides of the general formula

[0174] Ti (ORZ)4,

[0175] wherein Rzis an organic group, preferably a substituted or unsubstituted hydrocarbon group having 1 to 20 C atoms, and the 4 alkoxy groups -ORZare identical or different. Further, one or more of the -ORZgroups can be replaced by acyloxy groups -OCORZ.Likewise suitable as titanium catalysts are titanium alkoxides in which one or more alkoxy groups are replaced by a hydroxy group or halogen atoms.

[0176] Further, titanium chelate complexes can be used.

[0177] Aluminum catalysts can also be used as curing catalysts, e.g., aluminum alkoxides

[0178] AI(ORZ)3,

[0179] wherein Rzhas the above meaning; i.e., it is an organic group, preferably a substituted or unsubstituted hydrocarbon group having 1 to 20 C atoms and the three Rzgroups are identical or different. In the case of aluminum alkoxides as well, one or more of the alkoxy groups can be replaced by acyloxy groups -OC(O)RZ.

[0180] Further, aluminum alkoxides can be used in which one or more alkoxy groups are replaced by a hydroxy group or halogen atoms.

[0181] Of the described aluminum catalysts, the pure aluminum alcoholates are preferred in regard to their stability to moisture and the curability of the mixtures to which they are added. In addition, aluminum chelate complexes are preferred.

[0182] Suitable as zirconium catalysts are, e.g.: tetramethoxyzirconium or tetraethoxyzirconium.

[0183] Diisopropoxyzirconium bis(ethyl acetoacetate), triisopropoxyzirconium (ethyl acetoacetate), and isopropoxyzirconium tris(ethyl acetoacetate) are used with very particular preference.

[0184] Further, zirconium acylates can be used, for example.

[0185] Halogenated zirconium catalysts can also be used.

[0186] Further, zirconium chelate complexes can also be used.

[0187] In addition, carboxylic acid salts of metals or also a mixture of a number of such salts can be employed as curing catalysts, whereby these are selected from the carboxylates of the following metals: calcium, vanadium, iron, zinc, titanium, potassium, barium, manganese, nickel, cobalt, and / or zirconium.

[0188] Of the carboxylates, the calcium, vanadium, iron, zinc, titanium, potassium, barium, manganese, and zirconium carboxylates are preferred, because they exhibit a high activity. Calcium, vanadium, iron, zinc, titanium, and zirconium carboxylates are particularly preferred. Iron and titanium carboxylates are very particularly preferred.The curable compositions contain the curing catalyst preferably in an amount of from 0.05 to 2.0 % by weight, preferably 0.1 to 1.0 % by weight, based in each case on the total weight of the composition. If a mixture of different catalysts is used, the amounts refer to the total amount in the composition.

[0189] The curable compositions contain as component (E) at least one alkenyl-functional alkoxysilane.

[0190] According to a preferred embodiment, the alkenyl-functional alkoxysilane is selected from the group consisting of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, and mixtures thereof. Vinyltrimethoxysilane (VTMO) is particularly preferred.

[0191] According to a preferred embodiment, the curable compositions contain at least one alkenyl-functional alkoxysilane, in particular VTMO, in an amount from 0.1 wt% to 3.0 wt%, more preferably from 0.5 wt% to 2.0 wt%, most preferably from 0.5 wt% to 1.5 wt%, based on the total weight of the composition. If the alkenyl-functional alkoxysilane is contained less than 0.1 wt%, the composition does not have a sufficient water glycol resistance.

[0192] The curable compositions optionally contain as component (F) at least one urea-group containing silane. The urea-group containing silane refers to a compound comprising both at least one urea group and at least one hydrolysable silane group. Such urea silanes can be, and often are, the reaction product of, for example, an isocyanate, such as a polyisocyanate, i.e., a compound comprising two or more isocyanate groups per molecule, with an amino alkoxysilane.

[0193] According to a preferred embodiment of the invention, the curable composition may contain at least one urea-group containing silane in an amount of from 0.1 wt% to 3.0 wt%, more preferably from 0.3 wt% to 2.0 wt%, based on the total weight of the composition. The urea-group containing silane improves adhesion. If the urea-containing silane is contained more than 3.0 wt%, it may cause destabilization of the adhesive system.

[0194] The compositions of the invention crosslink in the presence of moisture and in so doing cure with the formation of Si-O-Si bonds.

[0195] The curable compositions can contain, apart from the components (A), (B), (C), (D), and (E), one or more components that can be used to selectively influence specific properties of the curable composition and / or the cured product.

[0196] These other components can be selected, for example, from the group comprising plasticizers, stabilizers, antioxidants, fillers, reactive diluents, drying agents, adhesion promoters, UV stabilizers, rheological aids, and / or solvents. Of particular importance are typically plasticizers, fillers, and stabilizers, comprising antioxidants and UV stabilizers.Preferably, the curable compositions therefore contain at least one further component.

[0197] It is conceivable that the viscosity of the curable composition is too high for certain applications. It can then be reduced in a simple and expedient way usually by using a reactive diluent, without any signs of demixing (e.g., plasticizer migration) occurring in the cured mass.

[0198] Preferably, the reactive diluent has at least one functional group which after application reacts, e.g., with moisture or atmospheric oxygen. Examples of groups of this type are silyl groups, isocyanate groups, vinylically unsaturated groups, and polyunsaturated systems.

[0199] All compounds that can be mixed with the other components with a reduction in viscosity and have at least one group reactive with the polymer can be used as reactive diluents.

[0200] The viscosity of the reactive diluent is preferably less than 20,000 mPas, particularly preferably about 0.1 to 6000 mPas, very particularly preferably 1 to 1000 mPas (Brookfield RVT, 23°C, spindle 7, 10 rpm).

[0201] The following substances, for example, can be used as reactive diluents: polyalkylene glycols reacted with isocyanatosilanes (e.g., Synalox 100-50B, DOW), carbamatopropyltrimethoxysilane, alkyltrimethoxysilane, alkyltriethoxysilane, such as methyltrimethoxysilane, methyltriethoxysilane, and vinyltrimethoxysilane (XL 10, Wacker), vinyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, octyltrimethoxysilane, tetraethoxysilane, vinyldimethoxymethylsilane (XL12, Wacker), vinyltriethoxysilane (GF56, Wacker), vinyltriacetoxysilane (GF62, Wacker), isooctyltrimethoxysilane (IO Trimethoxy), isooctyltriethoxysilane (IO Triethoxy, Wacker), N-trimethoxysilylmethyl-O-methyl carbamate (XL63, Wacker), N-dimethoxy(methyl)silylmethyl-0-methyl carbamate (XL65, Wacker), hexadecyltrimethoxysilane, 3-octanoylthio-1 -propyltriethoxysilane, and partial hydrolysates of said compounds.

[0202] Further, the following polymers from Kaneka Corp, can also be used as reactive diluents: MS S203H, MS S303H, MS SAT 010, and MS SAX 350.

[0203] Silane-modified polyethers which derive, e.g., from the reaction of isocyanatosilane with Synalox types can likewise be used.

[0204] Polymers that can be prepared from an organic framework by grafting with a vinylsilane or by reacting polyol, polyisocyanate, and alkoxysilane can be used, furthermore, as reactive diluents.

[0205] A polyol is understood to be a compound that may contain one or more OH groups in the molecule. The OH groups can be both primary and secondary.Suitable aliphatic alcohols include, for example, ethylene glycol, propylene glycol, and higher glycols, as well as other polyfunctional alcohols. The polyols can contain in addition other functional groups such as. e.g., esters, carbonates, or amides.

[0206] To prepare the preferred reactive diluents, the corresponding polyol component is reacted in each case with an at least difunctional isocyanate. Any isocyanate having at least two isocyanate groups may basically be used as the at least difunctional isocyanate, but within the scope of the present invention, compounds with two to four isocyanate groups, particularly with two isocyanate groups, are generally preferred.

[0207] Preferably, the compound present as the reactive diluent has at least one alkoxysilyl group, whereby of the alkoxysilyl groups, the di- and trialkoxysilyl groups are preferred.

[0208] Suitable as polyisocyanates for the preparation of a reactive diluent are, for example, ethylene diisocyanate, 1 ,4-tetramethylene diisocyanate, 1 ,4-tetramethoxybutane diisocyanate, 1.6-hexamethylene diisocyanate (HDI), cyclobutane-1 ,3-diisocyanate, cyclohexane-1 ,3 and -1 ,4 diisocyanate, bis(2-isocyanatoethyl) fumarate, as well as mixtures of two or more thereof, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane (isophorone diisocyanate, IPDI), 2,4- and 2,6-hexahydrotoluylene diisocyanate, hexahydro-1 ,3- or -1 ,4-phenylene diisocyanate, benzidine diisocyanate, naphthalene-1 ,5-diisocyanate, 1 ,6-diisocyanato-2,2,4-trimethylhexane, 1 ,6-diisocyanato- 2.4.4-trimethylhexane, xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), 1 ,3- and 1.4-phenylene diisocyanate, 2,4- or 2,6-toluylene diisocyanate (TDI), 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, or 4,4'-diphenylmethane diisocyanate (MDI), or the partially or completely hydrogenated cycloalkyl derivatives thereof, for example, completely hydrogenated MDI (H12-MDI), alkyl-substituted diphenylmethane diisocyanates, for example, mono-, di-, tri-, or tetraalkyl diphenylmethane diisocyanate and the partially or completely hydrogenated cycloalkyl derivatives thereof, 4,4'-diisocyanatophenyl perfluoroethane, phthalic acid bis-isocyanatoethyl ester, 1-chloromethylphenyl-2,4- or -2,6-diisocyanate, 1-bromomethylphenyl-2,4- or - 2.6-diisocyanate, 3,3-bis-chloromethyl ether-4,4'-diphenyl diisocyanate, sulfur-containing diisocyanates, as can be obtained by reacting 2 mol of diisocyanate with 1 mol of thiodiglycol or dihydroxydihexyl sulfide, the di- and triisocyanates of dimer and trimer fatty acids, or mixtures of two or more of the aforesaid diisocyanates.

[0209] Trivalent or higher valent isocyanates, as can be obtained, for example, by oligomerization of diisocyanates, particularly by oligomerization of the aforesaid isocyanates, can also be used as polyisocyanates. Examples of such trivalent and higher-valent polyisocyanates are the triisocyanurates of HDI or IPDI or mixtures thereof or mixed triisocyanurates thereof, as well as polyphenylmethylene polyisocyanate, as can be obtained by phosgenation of aniline-formaldehyde condensation products. Solvents and / or plasticizers can be used, in addition to or instead of a reactive diluent, for reducing the viscosity of the curable composition.Suitable as solvents are aliphatic or aromatic hydrocarbons, halogenated hydrocarbons, ketones, ethers, esters, ester alcohols, keto alcohols, keto ethers, keto esters, and ether esters.

[0210] The composition described herein can furthermore contain hydrophilic plasticizers. These are used to improve the moisture absorption and thereby to improve the reactivity at low temperatures. Suitable as plasticizers are, for example, esters of abietic acid, adipic acid esters, azelaic acid esters, benzoic acid esters, butyric acid esters, acetic acid esters, esters of higher fatty acids having approximately 8 to approximately 44 carbon atoms, epoxidized fatty acids, fatty acid esters and fats, glycolic acid esters, phosphoric acid esters, phthalic acid esters, linear or branched alcohols containing 1 to 12 carbon atoms, propionic acid esters, sebacic acid esters, sulfonic acid esters, thiobutyric acid esters, trimellitic acid esters, citric acid esters, and esters based on nitrocellulose and polyvinyl acetate, as well as mixtures of two or more thereof.

[0211] For example, of the phthalic acid esters, dioctyl phthalate, dibutyl phthalate, diisoundecyl phthalate, or butylbenzyl phthalate is suitable, and of the adipates, dioctyl adipate, diisodecyl adipate, diisodecyl succinate, dibutyl sebacate, or butyl oleate.

[0212] Also suitable as plasticizers are the pure or mixed ethers of monofunctional, linear or branched C4-16 alcohols or mixtures of two or more different ethers of such alcohols, for example, dioctyl ether (obtainable as Cetiol OE, Cognis Deutschland GmbH, Dusseldorf).

[0213] Endcapped polyethylene glycols are also suitable as plasticizers, for example, polyethylene or polypropylene glycol di-Ci-4-alkyl ethers, particularly the dimethyl or diethyl ethers of diethylene glycol or dipropylene glycol, and mixtures of two or more thereof.

[0214] Suitable plasticizers are endcapped polyethylene glycols, such as polyethylene or polypropylene glycol dialkyl ethers, wherein the alkyl group has up to four C atoms, and particularly the dimethyl and diethyl ethers of diethylene glycol and dipropylene glycol. An acceptable curing is achieved in particular with dimethyldiethylene glycol also under less favorable application conditions (low humidity, low temperature). Reference is made to the relevant technical chemistry literature for further details on plasticizers.

[0215] Also suitable as plasticizers are diurethanes, which can be prepared, for example, by reacting diols, having OH end groups, with monofunctional isocyanates, by selecting the stoichiometry such that substantially all free OH groups react. Optionally excess isocyanate can then be removed from the reaction mixture, for example, by distillation. A further method for preparing diurethanes consists of reacting monofunctional alcohols with diisocyanates, whereby all NCO groups are reacted if possible.

[0216] In various embodiments, the plasticizer may be a polydimethylsiloxane different from (A).In various embodiments, the curable composition comprises at least one plasticizer, for example a polydimethylsiloxane.

[0217] The curable compositions may contain the plasticizer preferably in an amount of 1 to 50% by weight, preferably in an amount of 10 to 40% by weight, particularly preferably in an amount of 20 to 30% by weight, based in each case on the total weight of the composition. If a mixture of plasticizers is used, the amounts refer to the total amount of plasticizers in the composition.

[0218] The composition described herein can contain in addition up to about 20% by weight of conventional adhesion promoters (tackifiers). Suitable as adhesion promoters are, for example, resins, terpene oligomers, coumarone / indene resins, aliphatic petrochemical resins, and modified phenol resins. Suitable within the context of the present invention are, for example, hydrocarbon resins, as can be obtained by polymerization of terpenes, primarily a- or / 3-pinene, dipentene, or limonene. These monomers are generally polymerized cationically with initiation using Friedel-Crafts catalysts. The terpene resins also include, for example, copolymers of terpenes and other monomers, for example, styrene, a-methylstyrene, isoprene, and the like. The aforesaid resins are used, for example, as adhesion promoters for contact adhesives and coating materials. Likewise suitable are terpene-phenol resins, which are prepared by the acid-catalyzed addition of phenols to terpenes or rosin. Terpenephenol resins are soluble in most organic solvents and oils and miscible with other resins, waxes, and caoutchouc. Likewise suitable as an additive in the aforesaid sense within the context of the present invention are the rosin resins and derivatives thereof, for example, the esters thereof.

[0219] Because particularly due to the presence of the aminosilane the curable compositions generally already exhibit very good adhesion to very many materials, however, the addition of other adhesion promoters can often be omitted.

[0220] Preferably, the curable composition may contain at least one stabilizer, selected from antioxidants, UV stabilizers, and drying agents.

[0221] All conventional antioxidants may be used as antioxidants. They are preferably present up to about 7% by weight, particularly up to about 5% by weight.

[0222] The composition herein can contain UV stabilizers, which are preferably used up to about 2% by weight, preferably about 1% by weight. The so-called hindered amine light stabilizers (HALS) are particularly suitable as UV stabilizers. It is preferred within the context of the present invention if a UV stabilizer is employed, which carries a silyl group and is incorporated into the end product during crosslinking or curing. The products Lowilite 75 and Lowilite 77 (Great Lakes, USA) are particularly suitable for this purpose. Further, benzotriazoles, benzophenones, benzoates, cyanoacrylates, acrylates, sterically hindered phenols, phosphorus, and / or sulfur can also be added.It is often useful to stabilize the compositions in regard to penetrating moisture by means of drying agents in order to increase the storability (shelf life) still further.

[0223] Such an improvement in storability can be achieved, for example, by using drying agents. All compounds that react with water with the formation of a group inert to the reactive groups present in the preparation are suitable as drying agents and thereby undergo the smallest possible changes in their molecular weight. Furthermore, the reactivity of the drying agents to moisture penetrating into the preparation must be higher than the reactivity of the groups of the silyl group-bearing polymer of the invention present in the preparation

[0224] Isocyanates, for example, are suitable as drying agents.

[0225] Advantageously, however, silanes are used as drying agents. For example, vinylsilanes such as 3-vinylpropyltriethoxysilane, oxime silanes such as methyl-0,0',0"-butan-2-one-trioximosilane or 0,0',0",0"'-butan-2-one-tetraoximosilane (CAS Nos. 022984-54-9 and 034206-40-1) or benzamidosilanes such as bis(N-methylbenzamido)methylethoxysilane (CAS No. 16230-35-6) or carbamatosilanes such as carbamatomethyltrimethoxysilane. The use of methyl-, ethyl-, or vinyltrimethoxysilane, tetramethyl- or tetraethylethoxysilane is also possible. Vinyltrimethoxysilane and tetraethoxysilane are particularly suitable in terms of cost and efficiency.

[0226] Also suitable as drying agents are the aforesaid reactive diluents, provided they have a molecularweight (Mn) of less than about 5000 g / mol and have end groups whose reactivity to penetrated moisture is at least as high as, preferably higher than, the reactivity of the reactive groups of the polymer used according to the invention.

[0227] Lastly, alkyl orthoformates or alkyl orthoacetates can also be used as drying agents, for example, methyl or ethyl orthoformate or methyl or ethyl orthoacetate.

[0228] The compositions generally contain about 0 to about 6% by weight of drying agent.

[0229] The composition described herein can additionally contain fillers. Suitable here are, for example, chalk, lime powder, precipitated and / or pyrogenic (fumed) silica, zeolites, bentonites, magnesium carbonate, diatomaceous earth, alumina, clay, tallow, titanium oxide, iron oxide, zinc oxide, sand, quartz, flint, mica, glass powder, and other ground mineral substances. Organic fillers can also be used, such as, for example, carbon black, graphite, wood fibers, wood flour, sawdust, cellulose, cotton, pulp, cotton, wood chips, chopped straw, and chaff. Short fibers such as glass fibers, glass filament, polyacrylonitrile, carbon fibers, Kevlarfibers, or polyethylene fibers may also be added. Aluminum powder is also suitable as a filler.The pyrogenic (fumed) and / or precipitated silica preferably have a BET surface area of 10 to 90 m2 / g. When they are used, they do not cause any additional increase in the viscosity of the composition of the invention, but contribute to strengthening the cured composition.

[0230] It is likewise conceivable to use pyrogenic and / or precipitated silica with a higher BET surface area, advantageously with 100 to 250 m2 / g, particularly 110 to 170 m2 / g, as a filler. Because of the higher BET surface area, the same effect, e.g., strengthening of the cured preparation, can be achieved at a smallerweight proportion of silicic acid. Further substances can thus be used to improve the composition described herein in terms of other requirements.

[0231] Suitable further as fillers are hollow spheres having a mineral shell or a plastic shell. These can be, for example, hollow glass spheres which are obtainable commercially under the trade names Glass Bubbles®. Plastic-based hollow spheres, e.g., Expancel® or Dualite®, are described, for example, in EP 0520426 B1. They are made up of inorganic or organic substances and each have a diameter of 1 mm or less, preferably 500 pm or less.

[0232] Fillers that impart thixotropy to the preparations are preferred for many applications. Such fillers are also described as rheological adjuvants, e.g., hydrogenated castor oil, fatty acid amides, or swellable plastics such as PVC. In order to be readily squeezable out of a suitable dispensing device (e.g., a tube), such preparations possess a viscosity from 3000 to 15,000, preferably 40,000 to 80,000 mPas, or even 50,000 to 60,000 mPas.

[0233] The fillers are preferably used in an amount of 1 to 80% by weight, particularly preferably 2 to 20% by weight, and very particularly preferably 5 to 10% by weight, based in each case on the total weight of the composition. Of course, mixtures of a number of fillers can also be used. In this case, the quantitative data naturally refer to the total amount of filler in the composition.

[0234] The preparation of the curable composition can take place by simple mixing the components (A) to (E), and optionally the other ingredients. This can take place in suitable dispersing units, e.g., a high-speed mixer. In this case, preferably, care is taken that the mixture does not come into contact with moisture as far as possible, which could lead to an undesirable premature curing. Suitable measures are sufficiently known and comprise, for example, working in an inert atmosphere, possibly under a protective gas, and drying / heating of individual components before they are added.

[0235] The compositions of the invention can be used as an adhesive or sealing or coating material.

[0236] The composition can be used, for example, as an adhesive, sealant, coating, and for the production of molded parts. A further field of application for the compositions is the use as a plugging compound, hole filler, or crack filler. The use as a sealant is preferred.The compositions are suitable, inter alia, for bonding plastics, metals, glass, ceramic, wood, wood-based materials, paper, paper-based materials, rubber, and textiles, for gluing floors, and for sealing building elements, windows, wall and floor coverings, and joints in general. In this case, the materials can be bonded to themselves or as desired to one another.

[0237] The following examples serve to explain the invention, but the invention is not limited thereto.

[0238] Examples

[0239] The comparative composition C1 and the compositions E1 to E4 according to the invention were prepared by mixing the raw materials listed in Table 1.

[0240] Table 1

[0241] C1 E1 E2 E3 Raw materials Parts by Parts by Parts by Parts by weight weight weight weight a , co-d i hyd roxy-te rm i n ated 42.45 42.45 42.45 42.45 polydimethylsiloxane (viscosity 6,000 cST)

[0242] Aluminium powder 0.7 0.7 0.7 0.7 Vinyl tris(ethyl lactatojsilane 6.44 6.44 6.44 6.44 3-Aminopropyltrimethoxysilane 0.38 0.38 0.38 0.38 Highly dispersed silica 3 3 3 3 Coated calcium carbonate (PCC) 25.2 25.2 25.2 25.2 ferroaluminum silicate 20.8 20.8 20.8 20.8 (trimethoxysilyl)propyl-urea 0.45 0.45 0.45 0.45 Dioctyltin(IV)-2-ethylhexanoate 0.1 0.1 0.1 0.1 Vinyltrimethoxysilane 0 0.5 1.0 2.0

[0243]

[0244] The prepared formulations were subjected to curing performance and mechanical property tests as follows:

[0245] Table 2

[0246] C1 E1 E2 E3 SkinoverTime (SOT) [min] 120 42 44 47 (7 days @25°C, 50% RH)

[0247] Tensile strength [N / mm2] 2.45 2.55 2.32 2.37 (7 days @25°C, 50% RH)

[0248] Elongation at break [%] 224 241 211 195 (7 days @25°C, 50% RH)

[0249] Shore A hardness 51 48.84 51.48 51.78 (7 days @25°C, 50% RH)

[0250]

[0251] Lap shear strength [N / mm2] 0.815 0.872 0.804 0.796 Steel-Steel

[0252] (7 days @25°C, 50% RH)

[0253] Lap shear strength [N / mm2] 1.01 0.938 0.876 0.832 Alu-Alu

[0254] (7 days @25°C, 50% RH)

[0255] Tensile strength [N / mm2]

[0256] Water / Glycol (50 / 50) resistance @ 120°C 1.3 1.72 1.9 1.84

[0257] 170h

[0258] Elongation at break [%]

[0259] Water / Glycol (50 / 50) resistance @ 120°C 130 213 246 202

[0260] 170h

[0261] Tensile strength [N / mm2]

[0262] Water / Glycol (50 / 50) resistance @ 120°C 0.78 1.02 1.07 0.96

[0263] 1000h

[0264] Elongation at break [%]

[0265] Water / Glycol (50 / 50) resistance @ 120°C 62.5 148 147 113

[0266] 1000h

[0267]

[0268] Measurement method

[0269] Determination of SkinoverTime: SkinoverTime (SOT) is defined as the time required for the material to skinover. The determination of the SOT was carried out according to ASTM D2377 under standard climate conditions (23 + / - 2°C, relative humidity 50 + / - 5%). To determine surface skin formation from an adhesive or sealing material, extrude approximately 50mm of the test material to 6mm wide onto a glass plate. Start timer and test with a metal stainless steel spatula by periodically bringing the spatula into contact with the sample. Note the time when the sample no longer transfers to the spatula as the skinovertime in minutes.

[0270] Measurement of Shore A hardness: Shore A hardness was measured according to ISO 868.

[0271] Tensile strength and elongation at break: the properties were determined in accordance with ASTM 412. The samples were cured as film at 25°C over 7 days and punched out into S1 shape. The specimen type S1 (Dog bone) was used and the speed of the pull head in the dynamometer was 500mm / min.

[0272] The lap shear samples were prepared with a bondline thickness of 1 mm and an overlap area of 12.5x25 mm using metal substrates. The lap shear strength of the cured silicones was measured in accordance with DIN EN 1465 with a speed of 50 mm / min at 25°C after 7 days of curing.

[0273] Water / Glycol resistance was measured in accordance with ASTM D471-16a.

[0274] The samples were cured as film at 25°C over 7 days and punched out into S1 (Dogbone) shape. The specimen type S1 (Dog bone) was immersed at 120°C in a 50 / 50 glycol / deionized water medium and conditioned at set time intervals. Tensile strength and elongation at break properties were thendetermined after conditioning in accordance with ASTM 412 at speed of the pull head in the dynamometer at 500mm / min.

Claims

Claims1. A curable composition comprising(A) at least one polyorganosiloxane, which has at least one hydroxy group bound to a silicon atom, (B) at least one silane of the formula (1):Si(R1)m(R2)n(R3)4-(m+n) (1)whereineach R1independently stands for:a substituted or unsubstituted alkyl, alkenyl, or alkynyl group;a substituted or unsubstituted cycloaliphatic group or aryl group;a substituted or unsubstituted heteroalicyclic group or heteroaryl group;each R2independently stands for a group of the general formula (2):-OCR42COOR5(2)whereineach R4independently stands for:hydrogen; ora substituted or unsubstituted alkyl, alkenyl, or alkynyl group;R5stands for:a substituted or unsubstituted alkyl, alkenyl, or alkynyl group;each R3independently stands for a group of the general formula (3):-OCR62CONR7R8(3)whereineach R6independently stands for:hydrogen ora substituted or unsubstituted alkyl, alkenyl, or alkynyl group;R7stands for:hydrogen,a substituted or unsubstituted alkyl, alkenyl, or alkynyl group,a substituted or unsubstituted cycloaliphatic group or aryl group,R8, ora group -(CH2)P-COOR9, wherein p is an integer from 2 to 10, particularly 2, and R9stands for a substituted or unsubstituted alkyl, alkenyl, or alkynyl group, or a substituted or unsubstituted cycloaliphatic group or aryl group;R8stands for a group of the general formula (4):-R10-SiR11o(OR12)3-o (4)whereinR10stands for:an alkylene group, optionally interrupted by a heteroatom;each R11independently stands for:a substituted or unsubstituted alkyl, alkenyl, or alkynyl group;each R12independently stands for:a substituted or unsubstituted alkyl, alkenyl, or alkynyl group,an acyl group,or a group of the formula (5):-CR132COOR14(5)whereineach R13independently stands for:hydrogen; ora substituted or unsubstituted alkyl, alkenyl, or alkynyl group;R14stands for:a substituted or unsubstituted alkyl, alkenyl, or alkynyl group; ando independently stands for 0, 1 , or 2, andm independently stands for 0 or 1 and n independently stands for 1 , 2, 3, or 4, whereby the sum n + m is a maximum of 4,(C) at least one aminosilane,(D) at least one curing catalyst, and(E) at least one alkenyl-functional alkoxysilane.

2. The curable composition according to claim 1 , wherein the at least one alkenyl-functional alkoxysilane is selected from the group consisting of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, and mixtures thereof, preferably is vinyltrimethoxysilane.

3. The curable composition according to claim 1 or 2, wherein the composition comprises at least one alkenyl-functional alkoxysilane in an amount of from 0.1 wt% to 3.0 wt%, preferably from 0.5 wt% to 2.0 wt%, more preferably from 0.5 wt% to 1.5 wt%, based on the total weight of the composition.

4. The curable composition according to at least one of claims 1 to 3, wherein the polyorganosiloxane, which has at least one hydroxy group bound to a silicon atom, is a polydiorganosiloxane, preferably a polydimethylsiloxane, which has at least one, preferably at least two terminal hydroxy groups.

5. The curable composition according to at least one of claims 1 to 4, wherein the polyorganosiloxane, which has at least one hydroxy group bound to a silicon atom, is an a, w-di hydroxy-terminated polydiorganosiloxane, particularly an a,oj-dihydroxy-terminated polydimethylsiloxane6. The curable composition according to at least one of claims 1 to 5, wherein the silane is a silane of the formula (1), whereineach R1independently of one another stands for an alkyl group having 1 to 10 carbon atoms, particularly methyl, ethyl, propyl, or isopropyl, for an alkenyl group having 2 to 10 carbon atoms, particularly vinyl or allyl, or an aryl group having 6 to 10 carbon atoms, particularly phenyl, and / oreach R2independently of one another stands for a group of the formula (2), wherein one of the R4groups stands for hydrogen and the second R4group stands for hydrogen or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, particularly methyl, and R5stands for a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, particularly having 1 to 4 carbon atoms, particularly preferably methyl or ethyl.

7. The curable composition according to at least one of claims 1 to 6, wherein the silane is a silane of the formula (1), wherein the sum n + m is 4, preferably m is 1 and n is 3.

8. The curable composition according to at least one of claims 1 to 7, wherein the silane of the formula (1) is selected from the group consisting of methyl tris(ethyl lactato)silane, ethyl tris(ethyl lactato)silane, phenyl tris(ethyl lactato)silane, vinyl tris(ethyl lactato)silane, tetra(ethyl lactato)silane, and mixtures thereof.

9. The curable composition according to at least one of claims 1 to 8, wherein the silane is a silane of the formula (1), whereinthe sum n + m is a maximum of 3, andeach R3independently of one another stands for a group of the formula (3), wherein one of the R6groups stands for hydrogen and the second R6group for hydrogen or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, particularly methyl, R7for hydrogen, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, particularly having 1 to 4 carbon atoms, and R8for a group of the formula (4), wherein R10is an alkylene group of the formula -(CH2)P-, where p is an integer from 1 to 6, particularly 3, each R11independently of one another stands for a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, particularly having 1 to 4 carbon atoms, particularly preferably methyl or ethyl, and each R12independently of one anotherstands for a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, particularly having 1 to 4 carbon atoms, particularly preferably methyl or ethyl.

10. The curable composition according to at least one of claims 1 to 9, wherein the at least one aminosilane is an aminosilane of the formula (6),(R15R7N)-R10-SiR11o(OR12)3-o (6)whereino, R7, R10, and each R11and each R12, in each case independently of one another, have the meanings given in claim 1 , andR15stands for:hydrogen,a substituted or unsubstituted alkyl, alkenyl, or alkynyl group.

11. The curable composition according to at least one of claims 1 to 10, wherein the at least one aminosilane is selected from the group consisting of 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(trimethoxysilylpropyl)amine, bis(3-triethoxysilyl)propylamine, and mixtures thereof.

12. The curable composition according to at least one of claims 1 to 11 , wherein the polyorganosiloxane and the silane of the formula (1) are present in the form of a prepolymer, whereby the prepolymer can be obtained by reacting the polyorganosiloxane and the silane of the formula (1).

13. The curable composition according to at least one of claims 1 to 12, wherein the at least one catalyst is a tin compound, preferably, an organotin compound, selected from the group consisting of 1 ,3- dicarbonyl compounds of bivalent or tetravalent tin, dialkyltin(IV) dicarboxylates, dialkyltin(IV) dialkoxylates, dialkyltin(IV) oxides, tin(ll) carboxylates, and mixtures thereof.

14. The curable composition according to at least one of claims 1 to 13, wherein the composition further comprises (F) at least one urea-group containing silane.

15. Use of a curable composition according to at least one of claims 1 to 14 as an adhesive, sealing, or coating material.

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