Cross-linkable compositions based on organosilicon compounds

Abstract

To provide a one-component sealant which is capable of rapid curing and exhibits high storage stability.SOLUTION: A composition producible using (A) an organopolysiloxane represented by the formula (R2O)3-aSiR1aO(SiR2O)nSiR1a(OR2)3-a (I), provided that the viscosity at 25°C is 6000 mPa s or more, (B1) a silane represented by the formula R34-b(R4O)bSi (II), provided that the molecular weight is greater than 195 g / mol, and optionally, (B2) a silicon compound represented by the formula R7c(R8O)dSiO(4-c-d) / 2 (III), provided that, in formula (III), the sum c+d is ≤3, at least two groups (R8O) are present in the silicon compound, and the viscosity at 25°C is 2000 mPa s or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a composition based on an organosilicon compound and crosslinkable by a condensation reaction, a method for producing the same, and a sealant, particularly for use as a caulking for natural stone.

Background Art

[0002] One-component sealants (RTV1 sealants) that can be stored in a water-free state and cure to form an elastomer when water enters at room temperature after excluding alcohol are already known. These products are used in large quantities, for example, in the construction industry. The base of these mixtures is an organopolysiloxane having an alkoxy group as a hydrolyzable reactive substituent. This reactive polydimethylsiloxane is generally prepared by a method called end-capping, which involves reacting an OH-terminated polydimethylsiloxane with an organyloxysilane in the presence of a catalyst. In this regard, reference can be made to, for example, US5055502A. In order to suppress downstream reactions from end-capping (chain extension and crosslinking), the organyloxysilane needs to be used in a large excess relative to the OH groups of the OH-terminated polydimethylsiloxane. As a result, the organyloxy polymer always contains an excess of organyloxysilane. Also, it has been found that end-capping can generally be carried out without causing equilibration only with very highly reactive organyloxysilanes such as methyltrimethoxysilane or vinyltrimethoxysilane.

[0003] As other reactive silanes, methyltriethoxysilane (MTEO) or vinyltriethoxysilane (VTEO) are also used. However, the reactivity of these latter two silanes is already low, and as can be inferred from US210647822B, there are limits to their use as endblockers for long-chain OH-terminated polydimethylsiloxanes. However, these silanes are actually employed as additional additives, for example, as moisture scavengers to enhance storage stability or as carrier materials for further active ingredients such as stabilizers or catalysts.

[0004] The requirements for RTV1 sealants are diverse. In particular, products that cure extremely rapidly after a certain processing time are desired. In addition to the catalysts used in RTV1 sealants, the reactivity of the crosslinking agents specifically used here is a decisive factor. In particular, commonly used tin and titanium compounds have the drawback of causing problems with storage stability or unwanted yellowing. Therefore, there is concern about limiting the amount of catalyst used in RTV1 sealants. However, in that case, the pressure to use very highly reactive silanes becomes even greater.

[0005] Furthermore, these sealants may consist of fillers, plasticizers, crosslinking agents, and various additives.

[0006] Furthermore, it is common practice to use functionalized alkylsilanes as what are called adhesion promoters. A typical example is the use of aminopropyltrimethoxysilane.

[0007] Of course, not only methyltrimethoxysilane but also all of these alkoxysilanes additionally present in RTV1 sealants may affect curing characteristics such as film-forming time, initial strength, and complete curing. However, this effect is very small and can generally be ignored. However, when using these silanes in the described RTV1 sealants, there are drawbacks that affect production, storage, and use.

[0008] One of the major drawbacks of existing RTV1 sealants is that in the caulking scenario, the base material in contact with the RTV1 sealant, especially natural stone, gets soiled. This is mainly caused by plasticizers that are not incorporated into the polymer matrix. The plasticizers migrate out of the sealant and may form a blackish border with an oily appearance at the contact area with the base material.

[0009] A known solution to this problem is to use very short-chain plasticizers, as disclosed in DE10227590B. Nevertheless, it has been found that there is an additional type of soiling that appears only when the base material is wet. The area in contact with the sealant is highly hydrophobic and does not get wet by water, so it appears to be much lighter in color than the rest of the base material. This phenomenon occurs regardless of the plasticizer used and also occurs when no plasticizer is added at all.

[0010] In contrast to the very highly reactive organoxysilanes described above, high molecular weight organoxysilanes are characterized by low reactivity because they contain long-chain organoxy groups directly bonded to silicon and long-chain organo groups. Summary of the Invention

[0011] The subject of the present invention is a composition crosslinkable by a condensation reaction, comprising (A) the formula: (R 2 O) 3-a SiR 1 a O(SiR2O) n SiR 1 a (OR 2 ) 3-a (I) (wherein, R may be the same or different and represents an optionally substituted monovalent hydrocarbon group, R 1 may be the same or different and represents an optionally substituted monovalent hydrocarbon group, R 2represents a monovalent hydrocarbon group which may be the same or different and is optionally substituted, a may be the same or different and is 0 or 1, preferably 1, n is an integer from 380 to 2000), provided that the viscosity at 25 °C is 6000 mPa·s or more, an organopolysiloxane, (B1) formula: R 3 4-b (R 4 O) b Si (II) (wherein, R 3 represents a monovalent hydrocarbon group which may be the same or different and has an SiC bond and is optionally substituted, R 4 represents a monovalent hydrocarbon group which may be the same or different and is optionally substituted, b is 2, 3, or 4, preferably 2 or 3.) represented by, provided that the molecular weight is greater than 195 g / mol, a silane (B2) formula: R 7 c (R 8 O) d SiO (4-c-d) / 2 (III) (wherein, R 7 represents a monovalent hydrocarbon group which may be the same or different and has an SiC bond and is optionally substituted, R 8 represents a monovalent hydrocarbon group which may be the same or different and is optionally substituted, c is 0, 1, or 2, d is 0, 1, 2, or 3) represented by, provided that in formula (III), the sum of c + d is ≦ 3, and there are at least two groups (R 8 O) present in the silicon compound, and the viscosity at 25 °C is 2000 mPa·s or less, a silicon compound, a composition that can be produced using. However, the composition of the present invention contains an organosilicon compound having a molecular weight of 195 g / mol or less in an amount of less than 0.5% by weight, preferably less than 0.1% by weight, based on the organopolysiloxane (A).

Mode for Carrying Out the Invention

[0012] Examples of the group R include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, 1-n-butyl, 2-n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl groups, hexyl groups such as n-hexyl group, heptyl groups such as n-heptyl group; octyl groups such as n-octyl group; isooctyl groups such as 2,2,4-trimethylpentyl group; nonyl groups such as n-nonyl group; decyl groups such as n-decyl group; dodecyl groups such as n-dodecyl group; octadecyl groups such as n-octadecyl group; cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl group, methylcyclohexyl group; alkenyl groups such as vinyl, 1-propenyl, 2-propenyl groups;, aryl groups such as phenyl, naphthyl, anthryl, phenanthryl groups; alkaryl groups such as o-, m-, p-tolyl groups; xylyl group and ethylphenyl group; aralkyl groups such as benzyl group, α- and β-phenylethyl groups and the like.

[0013] The group R is preferably a monovalent hydrocarbon group having 1 to 18 carbon atoms, more preferably a methyl, vinyl, or phenyl group, and particularly preferably a methyl group.

[0014] Group R 1 Examples include the monovalent hydrocarbon groups shown for R, and hydrocarbon groups substituted with an amino group.

[0015] Group R 1 is preferably a monovalent hydrocarbon group having 1 to 12 carbon atoms and optionally substituted by an amino group, more preferably a methyl group, an ethyl group, a vinyl group, a phenyl group, the group -CH2-NR 6’ R 5’ or the group CH2NR11’ and in the formula, R 5’ represents a hydrocarbon group having 1 to 12 carbon atoms, and R 6’ represents a hydrogen atom or group R 5’ and R 11’ represents a divalent hydrocarbon group which may have a hetero atom inserted therein.

[0016] More particularly, group R 1 is group -CH2-NR 6’ R 5’ or group CH2NR 11’ and in the formula, R 5’ , R 6’ and R 11’ have the same meaning as described above, and are very preferably -CH2-N[(CH2)2]2O, -CH2-N(Bu)2 or -CH2-NH(cHex), where Bu represents an n-butyl group and cHex represents a cyclohexyl group.

[0017] Examples of group R 5 and R 5 are, independently of each other, the hydrocarbon groups shown for R.

[0018] Preferably, group R 5 and R 5’ are, independently of each other, a methyl group, an ethyl group, an isopropyl group, an n-propyl group, an n-butyl group, a cyclohexyl group or a phenyl group, and more preferably an n-butyl group.

[0019] Examples of hydrocarbon groups R 6 and R 6’ are, independently of each other, the hydrocarbon groups shown for R.

[0020] Preferably, group R 6 and R 6’ are, independently of each other, a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, an n-propyl group, an n-butyl group or a cyclohexyl group, and more preferably an n-butyl group.

[0021] The divalent groups R 11 and R11’ Examples include, independently of each other, an alkylene group such as propane-1,3-diyl, butane-1,4-diyl, butane-1,3-diyl, 2-methylpropane-1,3-diyl, pentane-1,5-diyl, pentane-1,4-diyl, 2-methylbutane-1,4-diyl, 2,2-dimethylpropane-1,3-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl and 2-methylheptane-1,7-diyl, 2,2,4-trimethylpentane-1,5-diyl group; an alkenylene group such as a propene-1,3-diyl group; and the groups -CH2-CH2-O-CH2-CH2- and -CH2-CH2-NH-CH2-CH2-.

[0022] Group R 11 and R 11’ are, independently of each other, preferably a divalent hydrocarbon group having 4 to 6 carbon atoms which may be inserted by a heteroatom, preferably oxygen O- or nitrogen -NH-, more preferably CH2-CH2-O-CH2-CH2-.

[0023] Group R 2 Examples are the monovalent groups shown for R.

[0024] Group R 2 is preferably an alkyl group having 1 to 12 carbon atoms, more preferably a methyl group, an ethyl group, an n-propyl group or an isopropyl group, more particularly a methyl group or an ethyl group.

[0025] The organopolysiloxane (A) used in the present invention is preferably as follows. (MeO)2Si(Ox)O(SiMe2O) 30~2000 Si(Ox)(OMe)2, (MeO)2Si(DBA)O(SiMe2O) 30~2000 Si(DBA)(OMe)2, (MeO)2Si(cHx)O(SiMe2O) 30~2000 Si(cHx)(OMe)2, (MeO)2Si(R 3O(SiMe2O) 700 Si(R 3 )(OMe)2, (EtO)2Si(Ox)O(SiMe2O) 30~2000 Si(Ox)(OEt)2, (EtO)2Si(DBA)O(SiMe2O) 30~2000 Si(DBA)(OEt)2, (EtO)2Si(cHx)O(SiMe2O) 30~2000 Si(cHx)(OEt)2, or, (EtO)2Si(R 1 )O(SiMe2O) 700 Si(R 1 )(OEt)2, More preferably, (EtO)2Si(Ox)O(SiMe2O) 30~2000 Si(Ox)(OEt)2, (EtO)2Si(DBA)O(SiMe2O) 30~2000 Si(DBA)(OEt)2, or, (EtO)2Si(cHx)O(SiMe2O) 30~2000 Si(cHx)(OEt)2, Even more particularly, (EtO)2Si(Ox)O(SiMe2O) 30~2000 Si(Ox)(OEt)2, wherein Me is a methyl group, Et is an ethyl group, Ox is CH2-N[(CH2)2]2O, DBA is -CH2-N(nBu)2, cHx is CH2-NH(cHex), Bu is an n-butyl group, cHex is a cyclohexyl group, and R 1 represents Me, Et, a vinyl group, a phenyl group, DBA, Ox or cHx and has the same meaning within each individual compound.

[0026] The organopolysiloxane (A) used in the present invention all have a viscosity at 25 °C of preferably 6000 to 350000 mPa·s, more preferably 20000 to 120000 mPa·s.

[0027] The organopolysiloxane (A) may be commercially available off-the-shelf products and / or may be produced by methods common in silicon chemistry.

[0028] Group R 3 Examples of the group shown for R are as follows.

[0029] Group R 3 is preferably a linear, branched or cyclic hydrocarbon group having 1 to 16 carbon atoms, or a monovalent hydrocarbon group having 1 to 12 carbon atoms and substituted with an amino group on a carbon atom bonded to a silicon atom, more preferably a linear, branched or cyclic alkyl group, vinyl group, phenyl group, group -CH2-NR 6’ R 5’ or group CH2NR 11’ , where R 5’ represents a hydrocarbon group having 1 to 12 carbon atoms, and R 6’ represents a hydrogen atom or group R 5’ and R 11’ represents a divalent hydrocarbon group which may be inserted by a heteroatom.

[0030] Group R 4 Examples are the groups shown for R.

[0031] Preferably, group R 4 is a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group or isobutyl group, more preferably an ethyl group, n-propyl group or isopropyl group.

[0032] Examples of component (B1) optionally used in the present invention include n-hexyltrimethoxysilane, n-heptyltrimethoxysilane, n-octyltrimethoxysilane, n-nonyltrimethoxysilane, n-decyltrimethoxysilane, n-hexadecyltrimethoxysilane, cyclohexyltrimethoxysilane, phenyltrimethoxysilane, n-propyltriethoxysilane, n-butyltriethoxysilane, n-pentyltriethoxysilane, n-hexyltriethoxysilane, n-heptyltriethoxysilane, n-octyltriethoxysilane, n-nonyltriethoxysilane, n-decyltriethoxysilane, n-hexadecyltriethoxysilane, cyclohexyltriethoxysilane, phenyltriethoxysilane, methyltri-n-propoxysilane, ethyltri-n-propoxysilane, n-propyltri-n-propoxysilane, n-butyltri-n-propoxysilane, n-pentyltri-n-propoxysilane, n-hexyltri-n-propoxysilane, n-heptyltri-n-propoxysilane, n-octyltri-n-propoxysilane, n-nonyltri-n-propoxysilane, n-decyltri-n-propoxysilane, n-hexadecyltri-n-propoxysilane, cyclohexyltri-n-propoxysilane, phenyltri-n-propoxysilane, methyltriisopropoxysilane, ethyltriisopropoxysilane, n-propyltriisopropoxysilane, n-butyltriisopropoxysilane, n-pentyltriisopropoxysilane, n-hexyltriisopropoxysilane, n-heptyltriisopropoxysilane, n-octyltriisopropoxysilane, n-nonyltriisopropoxysilane, n-decyltriisopropoxysilane, n-hexadecyltriisopropoxysilane, cyclohexyltriisopropoxysilane, phenyltriisopropoxysilane, 2,2,4-trimethylpentyltrimethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, 2,2,4-trimethylpentyltriethoxysilane, (2,3,5,6-tetrahydro-1,4-oxazin-4-yl)methyltriethoxysilane, N,They are N-di-n-butylaminomethyltriethoxysilane, N-cyclohexylaminomethyltriethoxysilane, (2,3,5,6-tetrahydro-1,4-oxazin-4-yl)methyltrimethoxysilane, N,N-di-n-butylaminomethyltrimethoxysilane, and N-cyclohexylaminomethyltrimethoxysilane.,

[0033] Preferably, the silane (B1) used in the present invention is tetraethoxysilane, 2,2,4-trimethylpentyltrimethoxysilane, (2,3,5,6-tetrahydro-1,4-oxazin-4-yl)methyltriethoxysilane, phenyltrimethoxysilane or n-hexadecyltrimethoxysilane.,

[0034] Component (B1) may be a commercially available conventional product or may be prepared by a method common in silicon chemistry.,

[0035] In any case, the composition of the present invention contains component (B1) in an amount of preferably 0.5 to 7 parts by weight, more preferably 1 to 3.5 parts by weight, based on 100 parts by weight of component (A).

[0036] Examples of the group R 7 are the groups shown for R.,

[0037] The group R 7 is preferably a methyl group or a 2,2,4-trimethylpentyl group.,

[0038] Examples of the group R 8 are the groups shown for R.,

[0039] The group R 8 is preferably a methyl group or an ethyl group, more preferably a methyl group.,

[0040] Preferred examples of the silicon compound (B2) optionally used in the present invention are EtO(SiMe2O)3SiR 7 (OEt)2, (EtO(SiMe2O)3)2SiR 7 (OEt), MeO(SiMe2O)3SiR 7 (OMe)2, (MeO(SiMe2O)3)2SiR 7 OMe), EtO(SiMe2O)3SiR 7 (OEt)O(SiMe2O)3SiR 7 (OEt)2, MeO(SiMe2O)3SiR 7 (OMe)O(SiMe2O)3SiR 7 (OMe)2, EtO(SiMe2O) x Si(iOct)(OEt)2, (EtO(SiMe2O) x )2Si(iOct)(OEt), MeO(SiMe2O) x Si(iOct)(OMe)2, (MeO(SiMe2O) x )2Si(iOct)(OMe), EtO(SiMe2O) x Si(iOct)(OEt)O(SiMe2O)3Si(iOct)(OEt)2, MeO(SiMe2O) x Si(iOct)(OMe)O(SiMe2O)3Si(iOct)(OMe)2, [(EtO)3SiO 1 / 2 [(EtO)2SiO 2 / 2 [(EtO)SiO 3 / 2 [SiO 4 / 2 , or, [(EtO)2SiMeO 1 / 2 [(EtO)SiMeO 2 / 2 [MeSiO 3 / 2 , and, wherein Me is a methyl group, Et is an ethyl group, iOct is a 2,2,4-trimethylpentyl group, x = 1 to 9, and R 7 represents a linear, branched, or cyclic aliphatic hydrocarbon group having 2 to 8 carbon atoms, and within each compound, the group R 7has the same definition.

[0041] The silicon compound (B2) optionally used in the present invention is more preferably MeO(SiMe2O) x Si(iOct)(OMe)2, (MeO(SiMe2O) x )2Si(iOct)(OMe), MeO(SiMe2O) x Si(iOct)(OMe)O(SiMe2O)3Si(iOct)(OMe)2, [(EtO)3SiO 1 / 2 0.37 [(EtO)2SiO 2 / 2 0.41 [(EtO)SiO 3 / 2 0.20 [SiO 4 / 2 0.02 , or [(EtO)2SiMeO 1 / 2 0.18 [(EtO)SiMeO 2 / 2 0.48 [MeSiO 3 / 2 0.34 , where in the formula, Me is a methyl group, Et is an ethyl group, iOct is a 2,2,4-trimethylpentyl group, and x = 1 to 9.

[0042] The silicon compound (B2) optionally used in the present invention preferably has a viscosity at 25°C of 5 to 15 mPa·s.

[0043] The silicon compound (B2) optionally used in the present invention preferably has a molecular weight of 195 g / mol or more.

[0044] More specifically, the optionally used silicon compound (B2) has the following average composition. [R 7 (OMe)2O 1 / 2 e [R 7 Si(OMe)O 2 / 2 f [R 7 SiO​​​​​​​​​3 / 2 g [Me2SiO 2 / 2 h [Me2Si(OMe)O 1 / 2 i 、 wherein e = 0.05 to 0.15, f = 0.10 to 0.20, g = 0.00 to 0.10, h = 0.40 to 0.65, i = 0.10 to 0.30, e + f + g < h + i, e + f + g + h + i = 1, Me is a methyl group, and R 7 has the above definition.

[0045] The optionally used silicon compound (B2) can be produced by a general method in silicon chemistry, such as by equilibrating polydimethylsiloxane and trialkoxysilane under a basic catalyst.

[0046] When the composition of the present invention contains the component (B2), the amount is in any case preferably 1 to 20 parts by weight, more preferably 1 to 10 parts by weight, and particularly preferably 2 to 6 parts by weight based on 100 parts by weight of the component (A).

[0047] In addition to the components (A), (B1) and optionally (B2), the composition of the present invention may contain all substances that have been employed heretofore in compositions crosslinkable by a condensation reaction, such as an adhesion promoter (C), a curing accelerator (D), a plasticizer (E), a filler (F) and an additive (G).

[0048] The adhesion promoter (C) used may be any adhesion promoter that has been used heretofore in compositions crosslinkable by a condensation reaction.

[0049] The adhesion promoter (C) is preferably an organoxysilane having a glycidyloxy group, an amino group, a ureido group, an acryloyloxy group or a methacryloyloxy group, and further a partial condensate thereof.

[0050] ​​​Examples of the adhesion promoter (C) include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-aminopropyldimethoxymethylsilane, 3-aminopropyldiethoxymethylsilane, 3-(2-aminoethyl)aminopropyldimethoxymethylsilane, and 3-(2-aminoethyl)aminopropyldiethoxymethylsilane.

[0051] When the composition of the present invention contains the adhesion promoter (C), the amount is preferably 0.5 to 5.0 parts by weight, more preferably 1 to 3 parts by weight, in each case based on 100 parts by weight of the component (A).

[0052] The curing accelerator (D) used can be any of the curing accelerators that have been used so far in compositions that can be crosslinked by a condensation reaction.

[0053] Examples of the curing accelerator (D) include, for example, titanium compounds such as tetrabutyl or tetraisopropyl titanate, or titanium chelates such as bis(ethylacetoacetate)diisobutoxytitanium, or organotin compounds such as di-n-butyltin dilaurate, di-n-butyltin diacetate, di-n-butyltin oxide, dimethyltin diacetate, dimethyltin dilaurate, dimethyltin dineodecanoate, dimethyltin oxide, di-n-octyltin diacetate, di-n-octyltin dilaurate, di-n-octyltin oxide, and reaction products of these compounds with alkoxysilane, for example, the reaction product of di-n-butyltin diacetate and tetraethoxysilane. Preferably, they are di-n-octyltin diacetate, di-n-octyltin dilaurate, dioctyltin oxide, the reaction product of di-n-octyltin oxide and tetraethoxysilane, tetrabutyl titanate, tetraisopropyl titanate or bis(ethylacetoacetate)diisobutoxytitanium.

[0054] When the composition of the present invention contains the curing accelerator (D), the amount in any case is preferably 0.001 to 20 parts by weight, more preferably 0.001 to 1 part by weight, based on 100 parts by weight of the component (A).

[0055] Examples of the optionally used plasticizer (E) include dimethylpolysiloxane which is liquid at room temperature, blocked at the ends by trimethylsiloxy groups, and has a viscosity at 25 °C particularly in the range of 5 to 1000 mPa·s, or high-boiling hydrocarbons such as liquid paraffin or naphthene and mineral oil composed of paraffin units.

[0056] When the composition of the present invention contains the component (E), the amount in any case is preferably 5 to 30 parts by weight, more preferably 5 to 25 parts by weight, based on 100 parts by weight of the siloxane (A). The composition of the present invention preferably does not contain the plasticizer (E).

[0057] The filler (F) optionally used in the compounds of the present invention can be any desired filler known heretofore.

[0058] Examples of the filler (F) optionally employed are non-reinforcing fillers (F) having a BET surface area of up to 20 m 2 / g, such as quartz, diatomaceous earth, calcium silicate, zirconium silicate, zeolite; metal oxide powders such as aluminum oxide, titanium oxide, iron oxide or zinc oxide and / or their mixed oxides; barium sulfate, calcium carbonate, gypsum, silicon nitride, silicon carbide, boron nitride, glass powder; and plastic powders such as polyacrylonitrile powder; and, reinforcing fillers having a BET surface area of 20 m 2 / g or more, such as precipitated chalk; carbon blacks such as furnace black and acetylene black; silicas such as calcined silica and precipitated silica; and fibrous fillers such as plastic fibers.

[0059] The filler (F) optionally employed is preferably calcium carbonate or silica, more preferably silica, or a mixture of silica and calcium carbonate.

[0060] Preferred calcium carbonate products (F) are ground or precipitated and optionally surface-treated with a fatty acid such as stearic acid or its salts. Preferred silica is preferably calcined silica.

[0061] When the composition of the present invention contains a filler (F), the amount is in each case preferably 10 to 150 parts by weight, more preferably 10 to 130 parts by weight, and even more particularly 10 to 100 parts by weight, based on 100 parts by weight of the organopolysiloxane (A). The composition of the present invention preferably contains a filler (F).

[0062] Examples of the additive (G) include pigments, dyes, odorants, antioxidants; agents for affecting electrical properties such as conductive carbon black; flame retardants, light stabilizers; biocides such as bactericides, antibacterial agents and acaricides; cell generators such as azodicarbonamide; heat stabilizers; scavengers such as Si-N-containing silazanes or silylamides, such as N,N'-bis(trimethylsilyl)urea or hexamethyldisilazane; cocatalysts such as Lewis acids and Bronsted acids, such as sulfonic acids, phosphoric acids, phosphate esters, phosphonic acids and phosphonate esters; thixotropic agents such as hydrogenated castor oil or polyethylene glycol terminated with OH on one or both sides; agents for further adjusting the elastic modulus such as polydimethylsiloxane having an OH terminal group, and any desirable siloxane different from components (A), (B) and (C).

[0063] When the composition of the present invention contains the additive (G), the amount is in any case preferably 0.1 to 20 parts by weight, more preferably 0.1 to 15 parts by weight, and particularly 0.1 to 10 parts by weight based on 100 parts by weight of the organopolysiloxane (A). The composition of the present invention preferably contains the component (G).

[0064] In any case, each component of the composition of the present invention may be of one kind, or otherwise may be a mixture of at least two different kinds of such components.

[0065] The composition of the present invention is preferably produced without using components other than components (A) to (G).

[0066] The composition of the present invention preferably comprises the following: (A) An organopolysiloxane of formula (I), (B1) Silanes of formula (II), (B2) A silicon compound composed of units of formula (III), Optionally (C) an adhesion promoter, Optionally (D) a curing accelerator, Optionally (E) a plasticizer, Optionally (F) filler, and Optionally (G) additive is a composition that can be produced using them.

[0067] The composition of the present invention is more preferably the following: (A) Organopolysiloxane of formula (I), (B1) Silanes of formula (II), (B2) Silicon compound composed of units of formula (III), (C) Adhesion promoter, Optionally (D) curing accelerator, Optionally (E) plasticizer, Optionally (F) filler, and Optionally (G) additive is a composition that can be produced using them.

[0068] The composition of the present invention is more specifically the following: (A) Organopolysiloxane of formula (I), (B1) Silanes of formula (II), (B2) Silicon compound composed of units of formula (III), (C) Adhesion promoter, (D) Curing accelerator, Optionally (E) plasticizer, (F) Filler, and optionally (G) additive is a composition that can be produced using them.

[0069] In another preferred embodiment, the composition of the present invention is the following: (A) Organopolysiloxane of formula (I), (B1) Silanes of formula (II), (B2) Silicon compound composed of units of formula (III), (C) Adhesion promoter, (D) Curing accelerator, (F) Filler, and Optionally (G) additive is a composition (excluding (E) plasticizer) that can be produced using them.

[0070] In a further preferred embodiment, the composition of the present invention comprises the following: (A) an organopolysiloxane of formula (I), (B1) silanes of formula (II), (B2) siloxanes consisting of units of formula (III), (C) an adhesion promoter, (D) a curing accelerator, (F) a filler, and (G) an additive, and is a composition that can be produced using them (provided that it does not contain (E) a plasticizer).

[0071] To prepare the composition of the present invention, all the components can be mixed with each other in any order. This mixing can be carried out at room temperature under the pressure of the ambient atmosphere, that is, at about 900 - 1100 hPa. However, if desired, this mixing can also be carried out at a higher temperature, for example, in the range of 35 - 135 °C. Furthermore, in order to remove volatile compounds or air, it is also possible to carry out the mixing temporarily or continuously under reduced pressure, such as an absolute pressure of 30 - 500 hPa.

[0072] The mixing of the present invention is preferably carried out in the substantial absence of water, that is, preferably using raw materials having a water content of less than 10000 mg / kg, more preferably less than 5000 mg / kg, and even more particularly less than 1000 mg / kg. The mixing operation is preferably carried out under a blanket of an inert gas such as dry air or nitrogen, and the gas preferably has a water content of less than 10000 μg / kg, more preferably less than 1000 μg / kg, and even more particularly less than 500 μg / kg. After its production, the composition is preferably dispensed into commercially conventional moisture-proof containers such as cartridges, tubular pouches, pearl cans, and drum cans.

[0073] In one preferred procedure, the first components (A), (B), optionally (C) and (E) are mixed with each other, then any filler (F) is added, and finally any further components (D) and (G) are added, and the temperature during mixing preferably does not exceed 60 °C.

[0074] A further object of the present invention is a method for producing the composition of the present invention by mixing the individual components.

[0075] The method of the present invention can be carried out continuously, batchwise or semi-batchwise using known apparatus according to known methods.

[0076] The composition of the present invention and / or the composition produced according to the present invention can be stored in the absence of moisture and can be crosslinked by the ingress of moisture.

[0077] The typical water content of air is sufficient to crosslink the composition of the present invention. The composition of the present invention is preferably crosslinked at room temperature. If desired, they can also be crosslinked at temperatures higher or lower than room temperature, for example crosslinked at -5°C to 15°C or 30°C to 50°C, and / or carried out by a moisture concentration exceeding the normal moisture content of air.

[0078] Crosslinking is preferably carried out at a pressure of 100 to 1100 hPa, more particularly at the pressure of the ambient atmosphere, in other words at about 900 to 1100 hPa.

[0079] A further object of the present invention is a molded article produced by crosslinking the composition of the present invention.

[0080] The molded article of the present invention preferably has a stress at 100% elongation measured with an ISO 37 type 2 test piece of less than 0.4 MPa.

[0081] The composition of the present invention can be stored in the absence of water and can be used for all purposes for which it is possible to employ a composition that crosslinks to an elastomer by the ingress of water at room temperature.

[0082] Surprisingly, it has been found that it is possible to produce a sealant having good reactivity and high storage stability by exclusively using silanes having a molecular weight exceeding 195 g / mol.

[0083] Furthermore, surprisingly, it could be shown that crosslinkable compositions based only on high molecular weight silanes do not cause soiling of the peripheral zone affecting the caulking of natural stone, even when not containing an inert plasticizer at the same time. There was no expectation that such an undesirable effect would be completely avoided by a relatively small increase in molecular weight. On the contrary, the expectation of those skilled in the art was that alkoxysilanes with a high molecular weight due to low reactivity would require more time to be able to diffuse from the RTV1 sealant during the curing process of the sealant. Therefore, the effect of soiling of the peripheral zone as a result of the hydrophobization of the natural stone surface tended to be enhanced, at least because longer alkyl groups further enhanced the hydrophobization effect.

[0084] Therefore, the composition of the present invention is, for example, as a sealing compound for joints including vertical joints and for similar cavities having a clear width of, for example, 10 to 40 mm in buildings, land vehicles, watercraft and aircraft, or as an adhesive or cement compound, for example in the manufacture of window structures or display cases, and also, for example, in the manufacture of surface members or anti-slip coatings exposed to the continuous action of fresh or salt water, or protective coatings including elastomeric moldings, and has excellent suitability.

[0085] The advantages of the compositions of the present invention are that they are easy to manufacture and are distinguished by a very high storage stability.

[0086] A further advantage of the compositions of the present invention is that they exhibit very good handling properties during use and have excellent processing characteristics in a wide variety of applications.

[0087] An advantage of the crosslinkable composition of the present invention is that the modulus can be customized.

[0088] An advantage of the crosslinkable composition of the present invention is that it adheres very well to a wide variety of substrates.

[0089] An advantage of the crosslinkable composition of the present invention is that it does not cause soiling of the peripheral zone of the adjacent substrate. In particular, it has excellent suitability for grouting natural stone and artificial stone without soiling of the peripheral zone.

[0090] An advantage of the crosslinkable composition of the present invention is that it is very economical in terms of the substances used.

[0091] In the examples described below, all viscosity data relate to a temperature of 25 °C. Unless otherwise indicated, the following examples are carried out at the pressure of the ambient atmosphere, i.e. about 1000 hPa, at room temperature, i.e. about 23 °C, or at the temperature that occurs when the reactants are combined at room temperature without additional heating or cooling, and at a relative atmospheric humidity of about 50%. Furthermore, unless otherwise indicated, all parts and percentage data relate to weight.

[0092] Tensile strength, elongation at break, and stress at 100% elongation are determined in accordance with ISO 37 using type 2 test specimens.

[0093] In the context of the present invention, the dynamic viscosity of the organosilicon compound is measured in accordance with DIN 53019. The procedure is as follows. Unless otherwise indicated, the viscosity is measured at 25 °C using a Physica MCR 300 rotational rheometer from Anton Paar. For viscosities from 1 to 200 mPa·s, a coaxial cylinder measuring system (CC27) with an annular measuring gap of 1.13 mm is used, and for viscosities exceeding 200 mPa·s, a cone / plate measuring system (Searle system with CP50-1 measuring cone) is used. The shear rate is adjusted according to the polymer viscosity. (100 s -1 at 1 to 99 mPa·s, 200 s -1 at 100 to 999 mPa·s, 120 s -1 at 1000 to 2999 mPa·s, 80 s -1 at 3000 to 4999 mPa·s, 62 s -1 at 5000 to 9999 mPa·s, 50 s -1at 10,000 to 12,499 mPa·s, 38.5 s -1 at 12,500 to 15,999 mPa·s, 33 s -1 at 16,000 to 19,999 mPa·s, 25 s -1 at 20,000 to 24,999 mPa·s, 20 s -1 at 25,000 to 29,999 mPa·s, 17 s -1 at 30,000 to 39,999 mPa·s, 10 s -1 at 40,000 to 59,999 mPa·s, 5 s -1 at 60,000 to 149,999, 3.3 s -1 at 150,000 to 199,999 mPa·s; 2.5 s -1 at 200,000 to 299,999 mPa·s; 1.5 s -1 at 300,000 to 1,000,000 mPa·s).

[0094] In the present invention, the number average molecular weight Mn and the weight average molecular weight Mw are determined as follows: Method: Size exclusion chromatography (SEC) in accordance with DIN 55672-1 Flow rate: 1.00 mL / min Injection system: Agilent 1200 autosampler (manufactured by Agilent Technologies) Injection volume: 100 μL Eluent: In the case of products containing a phenyl group, tetrahydrofuran >99.5% stabilized with 250 ppm of 2,6-di-tert-butyl-4-methylphenol (BHT) was used, and in the case of materials not containing a phenyl group, analytical grade toluene >99.9% was used. All chemicals are commercially available, for example, from Merck KGaA, D-Darmstadt (DE). Column: Stationary phase: Polystyrene-divinylbenzene from Agilent Technologies. Four columns consisting of a pre-column with a length of 50 mm and three separation columns with a length of 300 mm were connected in series. The inner diameter of all columns was 7.8 mm. The particle size of the gel used was 5 μm. The pore size of the pre-column was 500 Å, and the pore sizes of the three separation columns were 10,000 Å, 500 Å, and 100 Å in sequence. Column temperature: Oven temperature 45 °C. The concentration was measured using an RI detector (measurement principle: deflection, type: Agilent 1200, cell volume: 8 μL, temperature: 45 °C). The system was calibrated using a commercially available polystyrene standard from Agilent as well. Concentration: 0.4 g / L (EasiCal, ready-made polystyrene calibrator, injection volume: 100 μL). As the internal standard substance for toluene as the eluent, tetrahydrofuran was used as the labeling substance, and as the internal standard substance for tetrahydrofuran as the eluent, toluene was used as the labeling substance. Calibration curve fitting: 3rd order polynomial FitPSS. Sample preparation: Approximately 15 - 50 mg of the sample to be measured was dissolved in each eluent (c = approximately 3 - 10 mg / mL). The sample amount was set to an amount that could obtain a clear RI signal. All samples could be completely dissolved in the eluent. Evaluation: The determined molar weight was rounded to the nearest hundred in all cases. The stain on the peripheral zone of the porous substrate was measured according to ASTM (American Society for Testing and Materials) C1248. A test piece composed of a sealant and sandstone was vulcanized at 23 °C and 50% relative humidity for 21 days, then compressed by 25%, and then stored for a total of 28 days. 1) At 23 °C and 50% relative humidity, 2) At a temperature of 70 °C in a thermal cabinet, and 3) Conducted in a UV test chamber as described in ASTM C 1248.

[0095] Subsequently, visually evaluate the stain on the peripheral zone. If there is no visible stain on the peripheral zone, the result is 0 mm. If a stain on the peripheral zone is confirmed, report the maximum width of the band showing the largest stain in mm and round it off to an integer.

Example

[0096] In the following examples, all mixtures were prepared using a Labmax planetary mixer.

[0097] Example 1 Preparation of siloxane A1 A mixture of 660 g of α,ω-dihydroxypolydimethylsiloxane having a viscosity of 80000 mPa·s and 220 g of α,ω-dihydroxypolydimethylsiloxane having a viscosity of 20000 mPa·s was stirred at 200 revolutions per minute for 5 minutes together with 30.44 g of a solution in which 0.04 g of 1,5,7-triazabicyclo[4.4.0]dec-5-ene was dissolved in 30.4 g of (2,3,5,6-tetrahydro-1,4-oxazin-4-yl)methyltriethoxysilane. After a reaction for 5 minutes, a mixture of 98.0 wt% of α,ω-bis((2,3,5,6-tetrahydro-1,4-oxazin-4-yl)methyldiethoxysilyl)polydimethylsiloxane having a viscosity of 51000 mPa·s, 1.9 wt% of (2,3,5,6-tetrahydro-1,4-oxazin-4-yl)methyltriethoxysilane and 0.1 wt% of ethanol was obtained.

[0098] Preparation of mixture M1 455 g of the reaction mixture obtained in the preparation of siloxane A1 was admixed with 10.6 g of a tetraethoxysilane hydrolyzate oligomer having a SiO2 content of 40% by total hydrolysis and condensation, available from Wacker Chemie AG, Munich (DE) under the name "SILIKAT TES 40", 6.3 g of a methyltriethoxysilane hydrolyzate oligomer having an average of 10 Si atoms per molecule, and 12.6 g of an equilibration product of 6.3 g of 3-aminopropyltriethoxysilane, and the mixture was stirred at 200 revolutions per minute for an additional 5 minutes. Next, 44 g of hydrophilic fumed silica having a surface area of 150 m 2 / g and available from Wacker Chemie AG under the name HDK® V15A was added, and the mixture was first stirred at 200 revolutions per minute for an additional 5 minutes until the fumed silica was completely wetted. Thereafter, stirring was continued at 600 revolutions per minute for 10 minutes under a reduced pressure of 200 mbar. Finally, 1.58 g of a solution in which 0.27 g of dioctyltin oxide was dissolved in 1.31 g of an equilibration product consisting of 0.655 g of a methyltriethoxysilane hydrolyzate oligomer having an average of 10 Si atoms per molecule and 0.655 g of 3-aminopropyltriethoxysilane, and 3 g of a 33 wt% solution in which octylphosphonic acid was dissolved in phenyltrimethoxysilane were added, and stirring was continued for an additional 5 minutes under reduced pressure (200 mbar).

[0099] Thereafter, this mixture was dispensed into commercially available standard cartridges and stored in a moisture-free state. Twenty-four hours after the production of the mixture, plaques having a thickness of 2 mm were drawn from these mixtures, and from these plaques, type 2 dumbbell test specimens were produced in accordance with ISO 37, 6th edition 2017-11 after curing at 23 °C and a relative humidity of 50% for 7 days.

[0100] The results are shown in Table 1.

[0101] Example 2 Preparation of oligomer mixture B2-2 240 g (3.25 mol) of α,ω-bis(trimethylsiloxy)polydimethylsiloxane having a viscosity of 1000 mPa·s, 234 g (1.0 mol) of trimethoxy(2,4,4-trimethylpentyl)silane (=iOctSi(OMe)3) available under the name SILRES® BS1316 from Wacker Chemie AG, and 0.80 g of a 21% sodium ethoxide solution in ethanol were mixed, and the mixture was heated at 110 °C for 4 hours. After the solution had cooled, 1.60 g of a 10% n-heptane solution of dimethyldichlorosilane was added to neutralize the mixture. This mixture was degassed on a rotary evaporator at 120 °C and a reduced pressure of 50 mbar. The composition of the mixture was determined by 29-SiNMR spectroscopy. The mixture contained 1.4 wt% of iOctSi(OMe)3, 0.4 wt% of Me2Si(OMe)2 and 98.2 wt% of an oligomer mixture, and the average composition was [iOctSi(OMe)2O 1 / 2 0.08 [iOctSi(OMe)O 2 / 2 0.15 [iOctSiO 3 / 2 0.05 [Me2SiO 2 / 2 0.43 [Me2Si(OMe)O 1 / 2 0.29 . The molecular weights measured by gel permeation chromatography were 929 g / mol (Mw) and 635 (Mn). The polydispersity (Mw / Mn) was 1.46.

[0102] Production of mixture M2 The production of mixture M1 described in Example 1 was repeated. Additionally, 36 g of the oligomer mixture B2-2 described above was admixed.

[0103] Thereafter, mixture M2 was dispensed into standard commercially available cartridges and stored in a moisture-free state. Twenty-four hours after the production of the mixture, plaques having a thickness of 2 mm were drawn from these mixtures, and from these plaques, type 2 dumbbell test specimens were produced in accordance with ISO 37, Edition 6, 2017-11 after curing at 23 °C and a relative humidity of 50% for 7 days.

[0104] ​​​​​ The results are shown in Table 1.

[0105] Example 3 Preparation of siloxane A3 A mixture of 660 g of α,ω-dihydroxypolydimethylsiloxane having a viscosity of 80000 mPa·s and 220 g of α,ω-dihydroxypolydimethylsiloxane having a viscosity of 20000 mPa·s was stirred at 200 revolutions per minute for 30 minutes together with 30.44 g of a solution in which 0.04 g of 1,5,7-triazabicyclo[4.4.0]dec-5-ene was dissolved in 30.4 g of phenyltrimethoxysilane. After a reaction for 30 minutes, a mixture of 98.0 wt% of α,ω-bis((phenyldimethoxysilyl)polydimethylsiloxane having a viscosity of 51000 mPa·s, 1.9 wt% of phenyltrimethoxysilane, and 0.1 wt% of methanol was obtained.

[0106] Production of mixture M3 In the procedure for producing mixture M1 described in Example 1, the siloxane used was changed to siloxane A3 instead of A1 and repeated.

[0107] Thereafter, mixture M3 was dispensed into a standard commercially available cartridge and stored in a moisture-free state. Twenty-four hours after the production of the mixture, plaques having a thickness of 2 mm were drawn from these mixtures, and from these plaques, type 2 dumbbell test pieces were produced after curing at 23 °C and a relative humidity of 50% for 7 days according to ISO 37, 6th edition 2017-11.

[0108] The results are shown in Table 1.

[0109] Example 4 Production of mixture M4 In the procedure for producing mixture M1 described in Example 1, the siloxane used was changed to siloxane A3 instead of A1 and repeated. Further, 36 g of the above oligomer mixture B2-2 was admixed.

[0110] Thereafter, the mixture M4 is dispensed into a standard commercially available cartridge and stored in a moisture-free state. 24 hours after the production of the mixture, plaques with a thickness of 2 mm are drawn from these mixtures, and after curing these plaques at 23 °C and a relative humidity of 50% for 7 days, type 2 dumbbell test pieces according to ISO 37, 6th edition 2017-11 are produced.

[0111] The results are shown in Table 1.

[0112] Example 5 Preparation of siloxane A5 A mixture of 660 g of α,ω-dihydroxypolydimethylsiloxane having a viscosity of 80000 mPa·s and 220 g of α,ω-dihydroxypolydimethylsiloxane having a viscosity of 20000 mPa·s was stirred at 200 revolutions per minute for 60 minutes together with 53.2 g of a solution in which 0.1 g of 1,5,7-triazabicyclo[4.4.0]dec-5-ene was dissolved in 53.1 g of n-hexadecyltrimethylsilane. After a reaction for 60 minutes, a mixture of 95.3 wt% of α,ω-bis((n-hexadecyltrimethylsilyl)polydimethylsiloxane having a viscosity of 50200 mPa·s, 4.6 wt% of phenyltrimethoxysilane and 0.1 wt% of methanol was obtained.

[0113] Production of mixture M5 In the procedure for producing the mixture M1 described in Example 1, the siloxane used was changed to siloxane A5 instead of A1, and the procedure was repeated. Further, 36 g of the above-described oligomer mixture B2-2 was admixed.

[0114] Thereafter, the mixture M4 is dispensed into a standard commercially available cartridge and stored in a moisture-free state. 24 hours after the production of the mixture, plaques with a thickness of 2 mm are drawn from these mixtures, and after curing these plaques at 23 °C and a relative humidity of 50% for 7 days, type 2 dumbbell test pieces according to ISO 37, 6th edition 2017-11 are produced.

[0115] The results are shown in Table 1.

[0116] Example 6 Preparation of Siloxane A6 A mixture of 660 g of α,ω-dihydroxypolydimethylsiloxane having a viscosity of 80000 mPa·s and 280 g of α,ω-trimethylsiloxypolydimethylsiloxane having a viscosity of 10 mPa·s was stirred at 200 revolutions per minute for 30 minutes together with 38.24 g of a solution in which 0.04 g of 1,5,7-triazabicyclo[4.4.0]dec-5-ene was dissolved in 38.2 g of phenyltrimethylsilane. After a reaction of 30 minutes, a mixture of 98.0 wt% of α,ω-bis((phenyldimethoxysilyl)polydimethylsiloxane having a viscosity of 50800 mPa·s, 1.9 wt% of phenyltrimethoxysilane and 0.1 wt% of methanol was obtained.

[0117] Production of Mixture M6 455 g of the reaction mixture obtained in the preparation of siloxane A6 was admixed with 11.1 g of an equilibration product of 5.55 g of a methyltriethoxysilane hydrolysis oligomer having an average of 10 Si atoms per molecule and 5.55 g of 3-aminopropyltriethoxysilane, and stirred at 200 revolutions per minute for an additional 5 minutes. Next, 42.2 g of hydrophilic calcined silica having a surface area of 150 m 2 / g, available under the name HDK® V15A from Wacker Chemie AG, was added, and the mixture was first stirred at 200 revolutions per minute for an additional 5 minutes until the calcined silica was completely wetted. Thereafter, stirring was continued at 600 revolutions per minute for 10 minutes under a reduced pressure of 200 mbar. Finally, 1.78 g of a solution in which 0.30 g of dioctyltin oxide was dissolved in 1.48 g of an equilibration product consisting of 0.74 g of a methyltriethoxysilane hydrolyzate oligomer having an average of 10 Si atoms per molecule and 0.74 g of 3-aminopropyltriethoxysilane, and 2.2 g of a 33 wt% solution in which octylphosphonic acid was dissolved in phenyltrimethoxysilane were added, and stirring was continued for an additional 5 minutes under reduced pressure (200 mbar).

[0118] Subsequently, the mixture M6 was dispensed into standard commercially available cartridges and stored in a moisture-free state. After 24 hours from the production of the mixture, plaques with a thickness of 2 mm were drawn from these mixtures, and from these plaques, after curing for 7 days at 23 °C and a relative humidity of 50%, type 2 dumbbell test specimens according to ISO 37, 6th edition 2017-11 were produced.

[0119] The results are shown in Table 1.

Table 1

[0120] No soiling of the peripheral zone was observed in any of the examples. After wetting the test specimens with water, no hydrophobized areas were observed on the sandstone.

Claims

1. A composition crosslinkable by a condensation reaction, comprising: (A) Formula: (R ２ O) ３－ａ SiR １ ａ O(SiR ２ O) ｎ SiR １ ａ (OR ２ ) ３－ａ (I) (In the formula, R may be the same or different and represents an optionally substituted monovalent hydrocarbon radical; R １ are the same or different and represent optionally substituted monovalent hydrocarbon radicals, R ２ are the same or different and represent optionally substituted monovalent hydrocarbon radicals, a may be the same or different and is 0 or 1; n is an integer from 380 to 2000. wherein the viscosity at 25°C is 6000 mPa·s or more; (B1) Formula: R ３ ４－ｂ (R ４ O) ｂ Si (-I) (In the formula, R ３ may be the same or different and represent an optionally substituted monovalent hydrocarbon group having a SiC bond; R ４ are the same or different and represent optionally substituted monovalent hydrocarbon radicals, b is 2, 3, or 4. , wherein the molecular weight is greater than 195 g / mol; (B2) Formula: R ７ ｃ (R ８ O) ｄ Yes （４－ｃ－ｄ）／２ (III) (In the formula, R ７ are the same or different and represent optionally substituted monovalent hydrocarbon radicals having a SiC bond, R ８ are the same or different and represent optionally substituted monovalent hydrocarbon radicals, c is 0, 1, or 2; d is 0, 1, 2, or 3. In the formula (III), the sum of c+d is ≦3, and at least two groups (R ８ O) is present and has a viscosity of 2000 mPa·s or less at 25°C; A composition which can be prepared using With the proviso that the composition comprises an organosilicon compound having a maximum molecular weight of 195 g / mol or less in an amount of less than 0.5% by weight, based on the organopolysiloxane (A).

2. group R ３ is a linear, branched or cyclic hydrocarbon group having 1 to 16 carbon atoms, or a monovalent hydrocarbon group having 1 to 12 carbon atoms and substituted on the carbon atom bonded to the silicon atom with an amino group.

3. 3. The composition of claim 1, wherein component (B1) comprises tetraethoxysilane, 2,2,4-trimethylpentyltrimethoxysilane, (2,3,5,6-tetrahydro-1,4-oxazin-4-yl)methyltriethoxysilane, phenyltrimethoxysilane, or n-hexadecyltrimethoxysilane.

4. The composition according to any one of claims 1 to 3, characterized in that the composition comprises component (B1) in an amount of 0.5 to 7 parts by weight, based on 100 parts by weight of component (A).

5. 5. The composition according to claim 1, further comprising an organosilicon compound having a molecular weight of up to 195 g / mol in an amount of less than 0.1% by weight, based on the organopolysiloxane (A).

6. The composition, (A) an organopolysiloxane of formula (I), (B1) silanes of formula (II), (B2) a silicon compound consisting of units of formula (III), optionally (C) an adhesion promoter; optionally (D) a cure accelerator; optionally (E) a plasticizer; optionally (F) a filler, and optionally (G) additives; The composition according to any one of claims 1 to 5, characterized in that it is a composition which can be produced using

7. The composition according to any one of claims 1 to 6, characterized in that the composition does not contain a plasticizer (E).

8. A process for producing a composition according to any one of claims 1 to 7 by mixing the individual components.

9. A molded article produced by crosslinking the composition according to any one of claims 1 to 7 or produced by the method according to claim 8.

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