CA2148665A1

CA2148665A1 - Organopolysiloxane compositions which can be cross-linked to elastomers with elimination of alcohols

Info

Publication number: CA2148665A1
Application number: CA002148665A
Authority: CA
Inventors: Michael Stepp; Stefan Oberneder; Erich Pilzweger
Original assignee: Individual
Current assignee: Wacker Chemie AG
Priority date: 1994-06-08
Filing date: 1995-05-04
Publication date: 1995-12-09
Also published as: AU2055295A; JPH07331077A; BR9502712A; KR960001040A; DE4420069A1; AU685255B2; CN1119658A; EP0686670A1; JP2716679B2

Abstract

Organopolysiloxane compositions which can be stored with exclusion of water but can be crosslinked to elastomers even at room temperature on addition of water, with elimination of alcohols, and which can be prepared using A) an .alpha.,.omega.-dihydroxyorganopolysiloxane, (B) an organosilicon compound of the formula [HSi(OR)2O1/2[Hsi(OR)O]b[HSiO3/2]c[Si(OR)3O1/2]d[Si(OR)2O]e[Si(OR)O3/2/]r[SiO2]g[R1O]h (I), wherein R is identical or different and is a monovalent, optionally substituted hydrocarbon radical or organosilicon radical, R1 is identical or different and is a divalent, optionally substituted organic radical and a, b, c, d, e, f, g and h are 0 or a number greater than 0, with the proviso that the content of Si-bonded hydrogen is 0.1% to 0.9% by weight, based on the total weight of the organosilicon compound of formula (I) are a monovalent, optionally substituted hydrocarbon radical, and optionally fillers, additives, catalysts, plasticizers, adhesion promoters and scavengers.

Description

- _ 214~66~

Docket: WA 9328-S
Paper No. 1 ORGA~IOPOLYSILOXANE COMPOSITIONS WHICH CAI~ BE
CROSSLIr.K~5L TO ELASTOMERS WITH ELI~INATIOII OF ALCOHOL~
Field of Invention 0 The present invention relates to organopolysiloxane compositions which can be stored with exclusion of water but, on access of water, can be cross1ink~d to elastomers even at room temperature with elimin~tion of alcohols, and to the crosslinking agents used for this process.
In the context of this invention, the term organopolysiloxanes l5 includes polymeric, oligomeric and dimeric organosiloxanes.
Background of Invention Organopolysiloxane compositions which can be cros~linke-l to elas-tomers with elimin~tion of alcohols and processes for their preparation are known. Reference may be made to U.S. 3,334,067 (Dow Corning Corp.;
20 issued August 1, 1967), in which a process for the preparation of organo-polysiloxane compositions, which can be crosslinked at room temperature, by mixing organopolysiloxane cont~ining hydroxyl groups with organyl(tri-organyloxy)silane and titanium compound is described. However, such compositions have a very low rate of crosclinkin~, so that metal compounds 25 must be added as a condensation catalyst to accelerate the reaction. To avoid the metal compounds, which are toxicologically unacceptable, WO 92/21724 (Wacker-Chemie GmbH; published on December 10, 1992) describes compositions which comprise organosilicon compounds with Si-bonded hydrogen and also organyloxy groups as crosslinkin~ agents and 30 crosslink even in the presence of mild condensation catalysts, such as car-boxylic acids. One disadvantage of these H-organylo~y cro~.slinking agents, is the evolution of hydrogen which occurs during prolonged storage because of the instability of the Si-H bond. The evolution of hydrogen during storage of the compositions can cause an increase in pressure in the drum, which 35 can result in an undesirable emergence of the composition when the drum ~1486G5 is opened. Furthermore, the evolution of hydrogen can cause inclusions of gas in the composition, which lead to processing difficulties because of inhomogeneities.
DE 41 17 471 A (Shin-Etsu Chem. Co., Ltd; published on May 29, 1990) and the corresponding US 5,166,293 describe compounds of the for-mula H-Si(OR)20[SiH-((OR)O~nSi(OR)3where R is an optionally substituted hydrocarbon radical and n is 0 or an integer, which are obtainable by treatment of mixtures of H-triaL~oxysilanes and alcohols with water and are used as primer precursors, intermediates for silane adhesion promoters and lo adhesion promoters for crosslink~hle silicone rubbers.
Summary of Invention The present invention relates to organopolysiloxane compositions which can be stored with exclusion of water but, on access of water, can be cros.~1ink~d to elastomers even at room temperature with elimination of alcohols, and which can be prepared using (A) an, a,~-dihydroxyorganopolysiloxane, (B) an organosilicon compound of the formula [HSi(OR)20l/2la[HSi~OR)O]b[HSiO3/2]c[Si(OR)30l/2¦d[Si(OR)20]e[Si(OR)03/2¦~¦SiO2¦~[RIO]h (1)~
wherein R is identical or different and is a monovalent, optionally substituted hydrocarbon radical or organosilicon radical, Rl is identical or different and is a divalent, optionally substituted organic radical and a, b, c, d, e, f, g and h are 0 or a number greater than 0.
with the proviso that the content of Si-bonded hydrogen is 0.1% to 0.9% by weight, preferably 0.2% to 0.8% by weight, more preferably 0.3% to 0.6% by weight, based on the total weight of the organosilicon compound of formula (I), and at least 20% of the number of radicals R in the organosilicon com-pound of formula (I) are a monovalent, optionally substituted hydrocarbon radical, and optionally other substances.
In the organopolysiloxane compositions according to the invention, component (A) is preferably a,a)-dihydroxyorganopolysiloxane of the formula ~1~8665 HO~(Si~O)nH (II) wherein R2 is identical or different, monovalent SiC-bonded organic radicals and n is a number of at least 20, preferably between 100 and 2000, more preferably between 500 and 1500, especially between 600 and 1400.
Although not shown by formula (II), up to 10 mole% of the diorganosi-loxane units can be replaced by other siloxane units, such as R2SiO3/2 0 and/or SiO4/2 units, wherein R2 has the meaning giYen above for this radi-cal. The organopolysiloxanes according to formula (II) can also contain up to 10 mole% of other functional groups, such as HR2SiO and HSiO3/2 groups, ori~n~ting from their preparation.
The radical R2is preferably a hydrocarbon radical having 1 to 18 car-15 bon atoms and is optionally substituted.
Examples of radicals R2 are alkyl radicals, such as the methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, n-pentyl, iso-pentyl, neo-pentyl and tert-pentyl radical, hexyl radicals, such as the n-hexyl radical, heptyl radicals, such as the n-heptyl radical, octyl radicals, such as the 20 n-octyl radical and iso-octyl radicals, such as the 2,2,4-trimethylpentyl radical, nonyl radicals, such as the n-nonyl radical, decyl radicals, such as the n-decyl radical, dodecyl radicals, such as the n-dodecyl radical, and octadecyl radicals, such as the n-octadecyl radical; alkenyl radicals, such as the vinyl and the allyl radical; cycloalkyl radicals, such as cyclopentyl, 25 cyclohexyl and cycloheptyl radicals and methylcyclohexyl radicals; aryl radicals, such as the phenyl, naphthyl and anthryl and phenanthryl radical;
alkaryl radicals, such as o-, m- and p-tolyl radicals, xylyl radicals and ethylphenyl radicals and arallyl radicals, such as the benzyl radical and the a- and the ~-phenylethyl radical.
Other examples of radicals R2 are linear or branched or cyclic hydro-carbon radicals substituted by acryloxy, methacryloxy, epoxy, allyl, cyclo-hexenyl and/or cyano groups and/or by halogen atoms.

~148~6~
-Examples of substituted radicals R2 are cyanoaL~cyl radicals, such as the ,B-cyanoethyl radical, and halogenated hydrocarbon radicals, for exam-ple haloaL~cyl radicals, such as the 3,3,3-trifluoro-n-propyl radical, the 2,2,2,2',2',2'-hexafluoroisopropyl radical and the heptafluoroisopro~yl radi-5 cal, and haloaryl radicals, such as the o-, m- and p-chlorophenyl radical.
More preferred radicals R2 are methyl, ethyl and n-propyl radicals, in particular the methyl radical.
Preferably, at least 90% of the number of radicals R2 in formula (II) are methyl radicals.
The a,6)-dihydroxydiorganopolysiloxane employed according to the invention can be identical or different homo- or copolymers, it being possible for the individual molecules to have the same or different chain lengths.
The a,~-dihydroxydiorganopolysiloxane employed according to the invention preferably have a viscosity at 25C of 1000 to 400,000 mm2/s, more preferably 20,000 to 350,000 mm2/s.
Examples of the a,~-dihydroxyorganopolysiloxanes according to for-mula (II) employed according to the invention are a,~d-dihydroxydimethyl-polysiloxanes, a,~-dihydroxydimethyl/methylvinylcopolysiloxanes, a,~- dihydroxydimethyl/methylphenylcopolysiloxanes and a,~- dihydroxy-20 dimethyl/methyl-3,3,3-trifluoro-n-propylcopolysiloxanes.
The a,~-dihydroxyorganopolysiloxanes employed in the compositioins according to the invention are commercially available products or can be prepared by processes known in silicon chemistry.
The radicals R are preferably hydrocarbon radicals having 1 to 10 25 carbon atoms, which can be substituted by alkoxy groups having 1 to 3 carbon atoms and other non-~lk~line organic radicals.
Examples of the radicals R are the examples of hydrocarbon radicals having 1 to 10 carbon atoms given for the radical R2, -CH2CH20CH3, -CH2CH2-OOCCH3, -CH2COOC4Hg, -CH2-C(O)CH3 and radicals of the for-30 mula-(SiR22O)rSiR23 where R2 has the above mentioned meaning and r is 0 to 100, examples of which are Me3Si-, Ph3Si- and CH2=CH(SiMe20)3SiMe2 radicals, where Me is the methyl radical and Ph is the phenyl radical.
More preferably, the radicals R are the methyl, ethyl, n-propyl, iso-propyl radical and CH30CH2CH2 radical, in particular the ethyl radical.
The radical Rl is preferably divalent linear radicals of the formula -(CqH2q oR'o~-, wherein 10 R' is a non-~lk~line organic radical, such as optionally substituted alkyl or aryl radicals, HO-, R"O-, - R"-COO and R"-CO-, where R" is an organic radical, q is a number from 2 to 20 and o is 0 or a number from 1 to 10, or divalent cyclic radicals of the for-mula -(CjH2j 2 1R'I)-, wherein R' has one of the above mentioned meanings, is a number from 3 to 8 and is 0 or a number from 1 to 8, and divalent aromatic radicals having 6 to 20 carbon atoms which are optionally substituted by R'.
Examples of the radical Rl are the methylene, ethylene, n-propylene, iso-propylene, l-n-butylene, 2-n-butylene, iso-butylene, tert-butylene, n-pentylene, iso-pentylene, neo-pentylene, tert-pentylene radical, hexylene radicals, such as the n-hexylene radical, heptylene radicals, such as the n-heptylene radical, octylene radicals, such as the n-octylene radical and iso-octylene radicals, such as the 2,2,4-t~imethylpentylene radical, nonylene radicals, such as the n-nonylene radical, and decylene radicals, such as the n-decylene radical, and cycloallcylene radicals, such as cyclopentylene, cyclohexylene and cycloheptylene radicals and methylcyclohexylene radi-cals, cyanoalkylene radicals, such as the ~-cyanoethylene radical, and halo-genated hydrocarbon radicals, for example haloalkylene radicals, such as the 3,3,-trifluoro-n-propylene radical and the 2,2,2,2',2',2'-hexafluoroiso-propylene radical, and haloarylene radicals, such as the o-, m- and p-chlorophenylene radical, as well as optionally substituted m- or ~1~8~5 p-propyloxyphenylene radicals, the 1,4-phenylene, 1,3-phenylene, 4,4'-biphenylene, 3,3'-biphenylene, 3,4'-biphenylene, 1,4-naphthalene-diyl, 1,5-naphthalenediyl, 1,4-anthraquinonediyl, 1,5-anthraquinonediyl, 2,6-anthraquinonediyl, diphenylmethane-4,4'-diyl, 2,2-bisphe.lylpropane-4,4'-diyl, 2,2-bis-phenylperfluoloplo~ane-4,4'-diyl, 3,3-bisphenylphthalide-4,4'-diyl and bisphenylsulphone-4,4,4'-diyl radical and the 2-methyl-1,4-phenylene,2-chloro- 1 ,4-phenylene, 2-phenyl- 1 ,4-phenylene,2-cyano- 1,4-phenylene,2,2'-dimethyl-4,4'biphenylene and 3,3'-dimethyl-4,4'diphenylene radical.
lo The radical Rl is more preferably divalent linear radicals -(CH2)2~-, in particular -(CH2)6-.
The present invention also relates to organosilicon compounds of the formula IHSi(OR)201/2]alHSi(OR)O]blHSiO3/2]clSi(OR)301/2hlSi(OR)20]~1Si(OR)03/2]~{SiO2lelRIO]h (1)~
wherein R is identical or different and is a monovalent, optionally substituted hydrocarbon radical or organosilicon radical, and Rl, a, b, c, d, e, f, g and h have the above mentioned meaning, with the proviso that the content of Si-bonded hydrogen is 0.1% to 0.9% by weight, preferably 0.2% to 0.8% by weight, more preferably 0.3% to 0.6% by weight, based on the total weight of the organosilicon compound of formula (I), and at least 20% of the number of radicals R in the organosilicon com-pound of formula (I) are a monovalent, optionally substituted hydrocarbon radical.
In the organosilicon compound of formula (I), preferably all the radi-cals R are a monovalent, optionally substituted hydrocarbon radical.
Component (B) according to the invention is preferably prepared by reaction of alcohol (1) with a partial hydrolysate (2) from organyloxysilanes of the formula HSi(OR)3 (III) and optionally alkanediols, wherein R is identical or different and is a monovalent, optionally substituted hydrocarbon radical.

~4~665 The partial hydrolysates (2) used in the reaction according to the invention are preferably prepared in accordance with the process described in the above mentioned WO 92/21724 by hydrolysis of silanes of formula (III), optionally, with an aL~canediol of the formula HO-Rl-OH, where Rl has 5 the above mentioned meaning, in the presence of acid catalysts with removal of the alcohol formed. Partial hydrolysates or partial condensates of compounds of formula (III) are more preferably prepared by slow addition of water to the compound of formula (III), optionally as a mixtue with HO-Rl-OH, wherein Rl has the above mentioned meaning, and optionally in lo the presence of Bronsted acids.
The preparation of these partial hydrolysates (2) is preferably carried out under a pressure of 900 to 1100 hPa at a temperature of 23C to 220C, more preferably 40C to 180C. However, it can also be carried out under higher or lower pressures.
The partial hydrolysates (2) thus obtained are preferably siloxane resins of the formula [HSi(OR)201/2]a [HSi(OR)OIb [HSiO3/2]c[Si(OR)301/2¦d 1Si(OR)2)¦e ISi(OR(03/2¦t~[SiO2¦g[RIO¦h (1~)~
wherein R is identical or different and is a monovalent, optionally substituted hydrocarbon radical and Rl, a', b', c' d', e', f', g' and h' are 0 or a number greater than 0, with the proviso that the content of Si-bonded hydrogen is higher than in constituent (B) of the compositions according to the invention.
The content of Si-bonded hydrogen is preferably 0.8% to 1.2% by 25 weight, based on the total weight of the partial hydrolysate (2) of formula (I').
Preferably in the partial hydrolysates (2) of formula (I') employed according to the invention, (a'+b'+c') is 2 [0.7-(a'+b'+c'+d'+e'+f'+g'+h')], and more preferably (a'+b'+c') is 2 [0.8-(a'+b'+c'+d'+e'+f'+g'+h')].
The silanes of formula (III) employed and the alkanediols can be one 30 type of a silane or alkanediol or a mixture of different silanes or alkanediols.
Examples of partial hydrolysates (2) are those of formula (I') where R = Et and a'=32.9 b'=49.9 c'=12.5 d'=4.0 e'=0.7 f'=g'=h'=0 R = Et and a'=45.0 b'=43.0 c'=12.0 d'=e'=f'=g=h'=0 ~l~Xti~

R = Et and a's33.2 b'=47.5 c'=12.5 d'=5.9 e'=0.9 f'=g'=h'=0 R = iPr and a'=40.0 b'=45.0 c'=15.0 d'=e'=f'=g'=h'=0 R = Me and a'=29.4 b'=41.2 c'=13.8 d'=9.4 e'=5.8 f'=0.4 g'=h'=0 where Et is the ethyl radical, Me is the methyl radical and iPr is the isopro-5 pyl radical.
If alkanediols are co-used during the partial hydrolysis, h in formula (I') has a value greater than 0.
The reaction according to the invention of these partial hydrolysates (2), which are rich in Si-bonded hydrogen, with alcohols ROH (1), wherein R
0 is a monovalent, optionally substituted hydrocarbon radical or organosilicon radical and can be identical or different from the radicals R present in the partial hydrolysate (2), is preferably carried out in the presence of catalysts (3) which accelerate the reaction of Si-bonded hydrogen with hydroxyl groups.
Examples of such catalysts t3) are NaOH, KOH, alkali metal alcoho-lates, such as lithium ethanolate, potassium t-butylate and sodium buty-late, amines, such as piperidine and tetramethylethylenefli~mine, hydroxy-lamines, such as diethylhydroxylamine, hydrogen chloride, acid ion ~oxh~ng-ers, Cu, Ni, Pd, BF3, ZnCl2, MgCl2, LiF, CsF, KF, t-butyl4NF and PdtCo complexes. Reference may be made to E. Lukevics, M. Dzintara, J. Organomet. Chem. 295 (1985), 265-315.
Basic compounds are preferably employed as catalysts (3) in the reaction according to the invention. Examples of these are basic metal salts, such as sodium bicarbonate, sodium carbonate and magnesium oxide, amines, guanidines, ureas, imines and hydroxylamine. Tertiary amines, in particular triethylamine, are more preferably employed as cata-lysts (3).
Examples of the alcohol (1) are methanol, ethanol, isopropanol, n-propanol, n-butanol, trimethylsilanol and triphenylsilanol.
The radical R in the alcohol ROH (1) employed according to the invention preferably has the same meaning as the radical R in the partial hydrolysate (2) of formula (I') employed. If R in the compound ROH (1) is ~1~86(i~i .
an organosilicon radical, alcohols will likewise be referred to for simplicity in the context of the present invention.
In the reaction according to the invention, partial hydrolysate (2) is preferably initially introduced into the reaction vessel together with the 5 catalyst (3) and alcohol (1), optiona11y mixed with water, is metered in.
The process according to the invention is preferably carried out at temperatures of between 0C and 120C, more preferably between 15C and 100C, under a pressure of between 900 and 1100 hPa.
A non-protic solvent can additionally be employed in the process o according to the invention if the solvent does not impair the desired reac-tion.
Examples of solvents which are optionally employed are aliphatic hydrocarbons, such as fractions from petroleum refining, pentane, hexane, heptane and octane, aromatic hydrocarbons, such as benzene, toluene, 15 o-xylene, m-xylene and p-xylene (partly) halogenated hydrocarbons, such as CCl4, chloroform and perchloroethylene, ethers, such as diethyl ether, dibu-tyl ether, methyl t-butyl ether, 1,2-dimethoxyethane, dimethylated poly-ethylene glycols, tetrahydrofuran and dioxane, carboxylic acid esters, such as methyl acetate, ethyl acetate, butyl acetate and ethyl formate, ketones, 20 such as acetone, methyl ethyl ketone, methyl t-butyl ketone and methyl sec-butyl ketone, and mixtures of the above mentioned solvents. The term solvent does not mean all the participants in the reaction must dissolve therein.
In the process according to the invention, the ratio of alcohol (1) to 25 partial hydrolysate (2) is chosen such that the organosilicon compound of formula (I) is formed with the desired content of Si-bonded hydrogen of 0.1% to 0.9% by weight. If the content of Si-bonded hydrogen is greater than 0.9% by weight, an undesirable evolution of hydrogen must be expected during a prolonged storage time of the crosslink~hle mixture with 30 exclusion of air. A content of Si-bonded hydrogen of less than 0.1% by weight means that, the skin formation times in the presence of weak Bron-sted acids become too long.

~14~(i 5 Examples of the organosilicon compounds of the average formula (I~
according to the invention are:
R = Et and a=7.3 b=6.4 c=1.3 d=31.6 e=40.7 f=12.7 g=h=0 (0.1%H/73.6%EtO), R = Et and a=19.0 b=24.0 c=7.0 d=12.0 e=25.0 f=13.0 g=h=0 (0.43%H/62.4%EtO), R = Et and a=15.4 b=24.2 c=11.4 d=5.5 e=20.5 f=18.7 g=4.3 h=0 (0.49%H/ 56.2%EtO), R = Et and a=21.6 b=29.3 c=10.4 d=6.1 e=19.1 f=ll.9 g=1.6 h=0 (0.57%H/50.4%EtO), R = Et and a=25.8 b=30.6 c=10.0 d=9.0 e=15.8 f=8.7 g=h=0 (0.6%H/60.8%EtO), R = Et and a=20.3 b=13.9 c=4.3 d=18.8 e=30.6 f=12.0 g=h=0 (0.3%H/66.1%EtO), l5R = Et and a=33.5 b=28.0 c=8.6 d=10.9 e=14.1 f=4.6 g=0.2 h=0 (0.61%H/63.1%EtO), R = iPr and a=34.9 b=37.3 c=7.8 d=3.2 e=7.0 f=9.8 g=h=0 (0.63%H/65.8%iPrO), R = 38%Et/62%iPr and H-SiO3/2:SiO2 = 1: 0.833 (0.45%H/ 19.9%EtO/-2043.2%iPrO) and R = Et and a=33.3 d=33.3 h=33.3 b=c=e=f=g=0 Rl= -(CH2)6- (56.5%EtO/0.25%H), wherein the percentage data relates to the weight and Et is the ethyl radical and iPr is the iso-propyl radical.
Component (B) employed according to the invention can be a single type or a mixture of at least two different types of organosilicon compounds of formula (I).
The organopolysiloxane compositions according to the invention which can be cros~linked to elastomers with elimin~tion of alcohols are preferably those which can be prepared from, based on the total weight of the organopolysiloxane composition, (A) 20% to 98% by weight, preferably 40% to 80% by weight, more pref-erably 30% to 70% by weight, of a,~-dihydroxyorganopolysiloxane, ~148665 ~B) 1% to 50% by weight, preferably 2% to 30% by weight, more pref-erably 3% to 20% by weight, of organosilicon compound of formula (I), ~C) 0% to 50% by weight, preferably 0.5% to 10% by weight, more pref-s erably 1% to 7% by weight, of additives, (D) 0% to 70% by weight, preferably 1% to 60% by weight, more pref-erably 5% to 50% by weight, of filler, (E) 0% to 70% by weight, preferably 0% to 60% by weight, more pref-erably 10% to 50% by weight, of plasticizer, (F) 0% to 20% by weight, preferably 0% to 10% by weight, more pref-erably 1% to 8% by weight, of adhesion promoter, (G) 0% to 20% by weight, preferably 0% to 10% by weight, more pref-erably 1% to 8% by weight, of scavenger and (H) 0% to 10% by weight, preferably 0.01% to 5% by weight, more pref-erably 0.1% to 3% by weight, of condensation catalyst.
The fillers (D), plasticizer (E), adhesion promoter (F), scavenger (G), condensation catalyst (H) and additives (C) employed in the organopolysilox-ane compositions according to the invention can be the same as those which have previously been used is organopolysiloxane compositions which can be 20 crosslinked to elastomers with ~limin~tion of alcohols, basic constituents being less suitable since they reduce the storage stability of the organopoly-siloxane compositions.
Examples of fillers (D) are non-reinforcing fillers, having a BET sur-face area of up to 50 m2/g, such as quartz, diatomaceous earth, calcium 25 silicate, zirconium silicate, zeolites, metal oxide powders, such as alumi-num, titanium, iron or zinc oxides or mixed oxides thereof, barium sul-phate, calcium carbonate, gypsum, silicon nitride, silicon carbide, boron nitride, glass powder and powders of plastic, such as polyacrylonitrile pow-der; reinforcing fillers, having a BEI surface area of more than 50 m2/g, 30 such as pyrogenically prepared silicic acid, precipitated silicic acid, carbon black, such as furnace black and acetylene black, and silicon/aluminum mixed oxides of high BET surface area; and fibrous fillers, such as asbestos ~1~8~5 and fibres of plastic. The fillers mentioned can be hydrophobized, by treat-ment with organosilanes or -siloxanes or with stearic acid or by etherific ation of hydroxyl groups to alkoxy groups.
Examples of plasticizers (E) are dimethylpolysiloxanes which are liq-5 uid at room temperature and blocked by trimethylsiloxy end groups, andmonofunctional oils, such as (CH3)3SiO(Si(CH3)20)40H or random mixtures of diorganopolysiloxanes which are monohydroxy-functional or dihydroxy-functional and contain triorganosilyl groups in the terminal units, polyglycol ethers, such as HO(CH2CH20)xCH3 and CH30(CH2CH20)xCH3, and high-10 boiling hydrocarbons, such as paraffin oils.
Examples of the adhesion promoters (F) employed in the organopoly-siloxane compositions according to the invention are silanes and organo-polysiloxanes having functional groups such as those with aminoalkyl, gly-cidoxypropyl or methacrylo~y~ro~yl radicals, and tetraaLkoxysilanes, urea 15 derivatives, isocyanurates or SiH-functional organopolysiloxanes with or without additionally organofunctional units.
Suitable scavengers (G) are all compounds which are capable of trapping molecules which reduce the storage stability of the organopoly-siloxane compositions such as water; alcohol or silanols.
Examples of such scavenger (G) are silanes of the formula R44 kSiZk (IV) wherein R4 is identical or different and has one of the me~ninps of R2, Z is a group which can easily be split off, such as -dCR', -NR"-CO-NRn2 and -ORn', wherein R', R" and R"' is identical or different and are organic radicals, and k is 1, 2, 3 or 4, for example, triacetoxymethylsilane, di(N-methylaceta-mido)dimethylsilane and diacetoxydimethylsilane, as well as carboxylic acid 30 anhydrides, carboxylic acid esters, isocyanates and molecular sieves. Scav-engers which are particularly suitable for trapping molecular hydrogen are llnssl1~1rated organic compounds according to US 4,489,191 (General Elec-tric Co.; issued on December 18, 1989).

~148SS5 -Examples of the condensation catalyst (H) are (organo)metallic com-pounds, such as tit~n~tes, organotin compounds, zinc and cobalt com-pounds, acid catalysts which are free from metal atoms, such as carboxylic acids, and basic catalysts which are free from metal atoms, such as amine.
Preferred condensation catalysts of this type are acid catalysts which are free from metal atoms, such as carboxylic acids or partial esters of di-, tri- and tetracarboxylic acids, such as malonic acid mono(2-ethylhexyl) ester, with carboxylic acids such as hexanoic acid, 2-ethylhexanoic acid, lauric acid, malonic acid and oleic acid being more preferably employed.
o Compounds which display their action as acid catalysts only on addition of water; such as carboxylic acid anhydrides and acyloxysilanes, such as acetoxysilanes, can also be employed as constituent (H).
Examples of additives (C) are pigments, dyestuffs, odiferous sub-stances, fungicides, oxidation inhibitors, agents for influencing the electricalproperties, such as conductive carbon black, agents which provide flame-repellent properties, light stabilizers and agents for increasing the skin for-mation time, such as silanes with an SiC-bonded mercaptoallyl radical, cell-generating agents, for example azodicarboxamide, heat stabilizers and thixotropic agents.
Constituents other than constituents (A) to (H) can also be employed in the organopolysiloxane compositions according to the invention. These can be the same as those which have previously been used in organopoly-siloxane compositions which can be crosslinked to elastomers with elimina-tion of alcohols, basic constituents being less suitable since they reduce the storage stability of the organopolysiloxane compositions.
Examples of such other constituents are silanes of the formula R5mSi(OR6)4-m (V)~
wherein R5 has one of the me~nings given for R2, R6 is a monovalent, optionally substituted hydrocarbon radical and m isOor 1, or partial hydrolysates or partial condensates thereof, such as hexa-~1~8~

methoxydisiloxane, resinous organopolysiloxanes, including those of R53SiOl/2 and SiO4/2 units, where R5 has one of the me~ning~ given above for this radical, purely organic resins, such as homo- or copolymers of acrylonitrile, styrene, vinyl chloride or propylene, corrosion inhibitors, poly-5 glycols, which can be esterified and/or etherified, solvents and mixtures oftwo or more types of such constituents.
Compounds which can be crosslinked by free radicals and which allow further cross1inking of the mixtures according to the invention, for example by heating to a certain temperature or by irradiation with electro-10 magnetic radiation, can also be employed as further constituents of theorganopolysiloxane compositions according to the invention. In most cases shorter skin formation times can thereby be realized. Examples of such compounds are described in W0 93/00405 (Wacker-Chemie GmbH; pub-lished on January 7, 1993), such as siloxane Bl according to Example 1 b), 5 a,~-bis(acryloxy-n-propyl)diorganopolysiloxane having on average 190 siloxane units, which contains 4 vinylmethyl units and 2 HS(CH2)3SiCH302/2 units as diorganosiloxy groups, in addition to dimethylsiloxy units, siloxane ABl according to Example 6a), mixtures according to Example 2 and a,a)-dihydroxydiorganopolysiloxanes with vinyl and thiol units, such as the 20 precursor to siloxane ABl according to Example 6 a).
Agents which form free radicals such as azo compounds, peroxides or photoinitiators, such as acyloins and benzophenone ketals, can be added to these specific mixtures to accelerate the crosslinking by free radicals. The content of these constituents, which can be crosslinked by free radicals, in 25 the organopolysiloxane compositions according to the invention is usually not more than 50% by weight, preferably not more than 20% by weight, more preferably not more than 10% by weight.
If an improvement in water wettability of the vulcanizates obtainable from the organopolysiloxane compositions according to the invention is 30 desired, it may be advantageous to add a hydrophilic polysiloxane modified with polyglycol ether, as described, for example, in the German Application P43 30 735.3(Wacker-Chemie GmbH; filed in Germany September 10, 1993 and corresponding U.S. application S.N. 08/299,382,fi1ed on ~148~6S
.
September 1, 1994). Surface effects which improve the ability to be coated with aqueous emulsion paints or the frictional properties in contact with substrate surfaces can thereby be achieved. The content of these hydro-philic modifiers in the organopolysiloxane composition according to the 5 invention is usuaUy not more than 20% by weight, preferably not more than 10% by weight, more preferably not more than 5% by weight.
The individual constituents (C), (D), (E), (F), (G) and (H) and constitu-ents optionaUy employed in the organopolysiloxane compositions according to the invention which can be crosslinked with elimination of alcohols can lO be one type of such constituents or a mixture of at least two types of such constituents.
The organopolysiloxane compositions according to the invention are more preferably those comprising, based on the total weight of the organo-polysiloxane composition, 15 (A) 30% to 70% by weight of a,~-dihydroxyorganopolysiloxane, (B) 3% to 20% by weight of organosilicon compound of formula (I), (C) 1% to 7% by weight of additives, (D) 5% to 50% by weight of filler, (E) 10% to 50% by weight of plasticizer, 20 (F) 1% to 8% by weight of adhesion promoter and (H) 0.1% to 3% by weight of condensation catalyst.
To prepare the compositions according to the invention, all the con-stituents of the particular composition can be mixed with one another in any desired sequence. This mixing can be carried out at room temperature 2s and under the pressure of the surrounding atmosphere, of about 900 to 1100 hPa. If desired, this mixing can also be carried out at higher tempera-tures, for example at temperatures in the range from 35C to 135C. Water is preferably excluded as far as possible during this mixing.
The usual water content of air is sufficient for cros~linking the com-30 positions according to the invention. If desired, the crosslinking can also becarried out at temperatures higher or lower than room temperature, for ex-ample at -5C to 10C or at 30C to 50C.

~14g6~5 The organopolysiloxane compositions according to the invention which can be crosslink~d to elastomers with elimin~tion of alcohols have the advantage that the rate of crosslinking can be varied within almost any desired range with otherwise constant properties of non-vulcanized compo-sition and of the vulc~ni7~tes. Thus, for the same formulation, the skin formation time of the organopolysiloxane compositions according to the invention can be adjusted to any desired time between 5 minutes and 500 hours merely by varying the content of Si-bonded hydrogen of component B.
The compositions according to the invention are distinguished by a o high storage stability. When stored over a period of more than twelve months, even at an elevated storage temperature at 40C - 70C, these com-positions display constant properties, specifically constant cros~linking properties, at any point in time.
The compositions according to the invention have the advantage that they display no evolution of hydrogen during storage over a period of more than twelve months, even at an elevated storage temperature, for example 40C to 70C.
A further advantage of the organopolysiloxane compositions prepared according to the invention, which can be crosslinked to elastomers with elimin~ion of alcohols, is that without metal catalysts, which are unaccept-able from the toxicological aspect, they cure completely to elastomers quickly using only mild condensation catalysts.
The process according to the invention has the advantage that organosilicon compounds having a low content of Si-bonded hydrogen can be prepared in a simple manner.
The compositions prepared according to the invention can be em-ployed for all intended uses for which organopolysilo~ne compositions which can be stored with exclusion of water and crosslink to elastomers on access of water at room temperature can be employed.
The compositions prepared according to the invention are suitable as se~ling compositions for joints, including joints which run vertically, and similar empty spaces of, for example, 10 to 40 mm clear width, in b~ lings, and land, water and air vehicles, or as adhesives or cementing composi-i~ 1 4 ,~ 3 tions, for window construction or in the production of aquaria or display windows, and for the production of protective co~tings, includir~g those for surfaces exposed to the constant action of fresh water or sea water, or co~tingS which prevent sliding, or of elastomeric shaped articles, and for S ins~ tin~ electrical or electronic devices.
In the examples described below, all the viscosity data are based on a temperature of 25C. Unless stated otherwise, the examples below are car-ried out under a pressure of the surrounding atmosphere, under 1000 hPa, and at room temperature at about 23C, or at a temperature which is estab-lished when the reactants are brought together at room temperature without additional heating or cooling. All the parts and percentages data relate to the weight, unless stated otherwise.
In the following examples, the shore A hardness is determined in accordance with DIN (Deutsche Industrie Norm) 53 505.87, the tear strength, the elongation at break and the modulus (tensile stress at 100%
elongation) are each determined in accordance with DIN 53504-85Sl and the tear propagation resistance is determined in accordance with ASTM
D635B-73.
The number average Mn and the weight average Mw are determined with the aid of gel permeation chromatography.
The following abbreviations are used:
Et ethyl radical and iPr isopropyl radical.
E~ample 1 - (A) preparation of SiH-rich partial hydrolysate 67.6 g of water are added dropwise to a mixture of 822 g (5 mole) of triethoxysilane and 0.09 ml of acetic acid at 25C. After a reaction time of one hour, volatile constituents are distilled off at 80C/5hPa and the residue is filtered over 5 g of filter aid (commercially obtain-able under the name ~Seitz-Super~ from Seitz Filterwerke, Bad Krellm~-~h). 425.8 g of a colorless, clear oil which has the following composition according to its 29Si- and lH-NMR spectrum are obtained as the residue:
32.9 mole% of IHSi(OEt)2Ol/2¦

~8~55 49.9 mole% of IHSi(OEtJO]
12.5 mole% of ¦HSiO3/2]

4.0 mole% of ISi(OEt)3Ol/2]
0.7 mole% of ISi(OEt)2O]
A content of Si-bonded hydrogen of 0.94% by weight and an ethoxy content of 57.5% by weight are calculated from this.
22.5 g of ethanol are added to a mixture of 50 g of the partial hydrolysate prepared above under (A) and 0.5 g of triethylamine at 70C. The mixture is allowed to react at 70C for two hours and all o the volatile constituents are then stripped off on a rotary evaporator at 70C/ lhPa. 64 g of a clear, colorless filtrate having a number average Mn of 613 and a ratio of the weight average Mw to the number average Mn of 1.50 and having the following composition according to 29Si- and lH-NMR spectroscopy are obtained:
7.3 mole% of ¦HSi(OEt)2Ol/2]
6.4 mole of IHSi(OEt)O]
1.3 mole% of ¦HSiO3/2]
31.6 mole% of ISi(OEt)3O
40.7 mole% of ISi(OEt)2O]
12.7 mole% of ISi(OEt)O3/2]
A content of Si-bonded hydrogen of 0.10% by weight and an ethoxy content of 69.1% by weight are calculated from this.
I~:~ample 2 - (A) Preparation of SiH-rich partial hydrolysate 27.2 (1.51 mole) of water are added to a mixture of 412 g (2 mole) of triisoplo~oxysilane and 0.044 ml of acetic acid at 50C. The mix-ture is subsequently heated to 120C, first under normal pressure and then under 15 hPa, and is filtered over a mixture of 10 g of filter aid (commercially obtainable under the name ~Seitz-Super~ from Seitz Filterwerke, Bad Kreuznach) and 1 g of sodium bicarbonate. 181 g of a clear colorless oil with a viscosity of 10 mm2/s which has the fol-lowing composition according to its 29Si- and lH-NMR spectrum are isolated as the end product:
40.0 mole% of IHSi(OiPr)2Ol/2]

45.0 mole% of IHSilOiPr)O
15.0 mole% of IHSiO3/2l A content of Si-bonded hydrogen or 0.86% by weight and an isopropoxy content of 63.4% by weight are calculated from this.
E~ample 3 18 g of ethanol are added to a mixture of 100 g of the partial hydrolysate prepared in Example 1 under (A) and 1 g of triethyl~ ine at 70C. The mixture is allowed to after-react at 70C for one hour, all the volatile constitutents are then stripped off on a rotary evapora-tor at 70C/ lhPa and the residue is filtered over 2 g of filter aid (commercially obtainable under the name ~Seitz-Super~ from Seitz Filterwerke, Bad Kreumach). 86 g of a clear, colorless filtrate with a viscosity of 7 mm2/s, a number average Mn of 857 and a ratio of the weight average Mw to the number average Mn of 1.84 which has the following composition according to 29Si- and lH-NMR spectroscopy are obtained:
19 mole% of ¦HSi(OEt)2Ol/2]
24 mole% of [HSi(OEt)O]
7 mole% of [HSiO3/2]
12 mole% of [Si(OEt~301/2]
25 mole% of Si(OEt)20]
13 mole% of [Si(OEt)03/2]
A content of Si-bonded hydrogen of 0.43% by weight and an ethoxy content of 62.4% by weight are calculated from this.
E~ample 4 67.6 g of water are added dropwise to a mixture of 822 g (5 mole) of triethoxysilane and 0.09 ml of acetic acid at 25C. After a reaction time of one hour, volatile constituents are distilled off at 100C/ 10hPa, 4 g of triethylamine are then added and 60 g (1.3 mole) of ethanol are metered in at 90C in the course of one hour. The mixture is stirred at 70C for an additional hour. After the volatile constituents have been distilled off at 100C/ 10hPa, 297 g of a colorless, clear oil with a viscosit~r of 38 mm2/s which has the ~1~86/;S

following composition according to its 29Si- and lH-NMR spectrum remain as the residue:
15.4 mole% of lHSi(OEt)2Ol/2¦
24.2 mole% of [HSi(OEt)O]
11.4 mole% of [HSiO3/2¦

5.5 mole% of [Si(OEt)3Ol/2¦
20.5 mole% of lSi(OEt)201 18.7 mole% of [Si(OEt)03/2]
4.3 mole% of [SiO2l A content of Si-bonded hydrogen of 0.486% by weight and an ethoxy content of 56.2% by weight are calculated from this.
Example 5 The procedure described in Example 4 is repeated, with the modifi-cation that instead of 60 g of ethanol, 55 g (1.2 mole) of ethanol are employed. 337 g of a clear, colorless oil which has a viscosity of 10 mm2/s and the following composition according to its 29Si- and lH-NMR spectrum are isolated as the end product:
21.6 mole% of [HSi(OEt)20 29.3 mole% of [HSi(OEt)O]
10.4 mole% of [HSiO

6.1 mole% of [Si(OEt)30 19.1 mole% o [Si(OEt)201 11.9 mole% of [Si(OEt)O3/2¦
1.6 mole% of [SiO2]
A content of Si-bonded hydrogen of 0.57% by weight and an ethoxy content of 58.8% by weight are calculated from this.
E~ample 6 57.2 parts of a,cD-dihydroxydimethylpolysiloxane having a viscosity of 80,000 mm2/s, 44.0 parts of a,a)-di(trimethylsilo~y)-dimethylpoly-siloxane having a viscosity of 100 mm2tS, 11.0 parts of H-aL~oxy crosslinking agent, the preparation of which is described in Example 5, 0.44 part of oleic acid and 11 parts of hydrophobized pyrogenic silicic acid (commercially obtainable under tne name WACKER HDK

~1~8~

hl5~ from Wacker-Chemie GmbH) are mi~ed using a laboratory mixer (Janke & Kllnk~] RE 162). The co.llpo~lion formed is kept for 30 minutes at a te~l,p~ re of 50C with exclusion of air.
It is then ev~ t~l under a pressure of 0.5 hPa for 5 minutes, S while ~ ing. The co~psotion thus obtained is introduced into tubes and stored at 50C. After preparation of the composition and after storage at 50C for 1, 3 and 6 months, a portion of the co~uposilion is spread to a film 2 mm thick and the time taken for a dry surface to form ~skin form~ti~n time tH) and the merh~nical values of the elas-lo tomers are dete.~ The results are to be found in Table 1.
Table 1 Stor~ge t~ Shore Elongs- Tear ~oA~ R Tear time [min] ~ tion at s~rength [N/nm~] propa-[months] ,~.ard- break [N/m$~] gation ness [%] reRiR_ tance ' [N/mm) 0 19'25 3601.5 0.5 4.8 1 ;9,~8 410'.5 0.4 4.9 3 18~7 4001.3 0.4 4.8 6 1828 420l1.4 0.5 5.0 No evolution of hydrogen was detected in the obse, v~tion pcriod.
E~mple 7 57.2 parts of a,a~-dihydroxydimeLh~ )oly~ Y~ne having a viscosiL~
of 80,000 mm2/s, 44.0 parts of a,~-di(trimethylsiloxy)-dimethylpoly-siloxane having a viscosity of 100 mm2/s, 11.0 parts of H-alkoxy clo~d;nhng agent, the ~re~al~tion of which is described in Example 3, 0.44 part of oleic acid and 11 parts of hydrophobized pyrogenic silicic acid (commercially obtainable under the name ~WACKER HDK
H15~ from Wacker-Chemie GmbH) are mixed using a laboratory mixer (Janke & Kunkel RE 162). The composition formed is kept for 30 minutes at a temperature of 50C with exclusion of air. It is then evacuated under a pressure of S kPa for S minutes, while stirring.

~ ~ ~8~S~

The composition thus obtained is introduced into tubes and stored at50C.
After plepa~ation of the composition and after storage at 50C for 1, 3 and 6 months, a portion of the compoeitior- is spread to a film 2 mm thick and the time taken for a dry surface to form (skin formation time tH) and the mech~nic~l values of the el~tomers are d~t~.~i"ed.
The results are to be found in Table 2.
Table 2 Stora~e t~ ,Shore Elonga- ¦Te~r ~A~ Te~r time [min] ,A tion at I s~rength [N/nD~] prop~-[months] hard- break i[N/mm~] gation ~ess [%] re~is-tance [N/~]
0 45 ~21 3201.2 0.4 4.1 lS 1 43 20 350' 1.4 0.4 4.3 3 43 22 330 ... 3 0.3 4.1 6 ,40 21 330,1.4 0.4 4.4 No evolution of hydrogen was detected in the observation pcriod.
E~cample- 8 57.2 parts of a,~-dihydroxydimeLhylpolysilnY~ne having a visoo~iLy of 80,000 mm2/s, 44.0 parts of a,c3-di(trimethylsiloxy)-dimethyl-polys~ Y~ne having a viscosity of 100 mm2/s, 11.0 parts of H-alkoxy o~ kinp agent, the preparation of which is described in FY~mple 1, 0.44 part of oleic acid and 11 parts of hydrophobized p,~lO~liC
silicic acid (commercially obtainable under the name ~WACKER HDK
H15~ from Wacker-Chemie GmbH) are mixed using a laboratory miYer (Janke & KllnkPl RE 162). The composition formed is kept for 30 minutes at a te...pe,~ture of 50C with exclusion of air. It is then evz~ tP~l under a pressure of O.S kPa for 5 minutes, while stirring.
The composition thus obtained is introduced into tubes and stored at 50C.
After preparation of the composition and after storage at 50C for 1, 3 and 6 months, a protion of the composihon is spread to a film 2 ~14~

mm thick and the time taken for a dry surface to form (skin form~hon time tH) and the mechanical values of the elastomers are determine~l The results are to be found in Table 3.
Table 3 S Storage '~ IShor~ Elonga- ~ear ~n~ y~ Tear time [d] iA tion at strength tN/ ,'] propa-[months] lhard- break [N/mm~] gation ,ness [%] re~is-tance [N/mm]
o ; l7 220 0.6 0.1 2.3 1 3 10 270 0.7 0.1 2.7 3 3 10 210 0.9 0.1 2.9 6 3 lll 250 0.8 0.1 2.5 No evolution of Lyd~og~.l was detected in the observation penod.
Compariso~l E~cample 1 57.2 parts of a,~D-dih~ ydimel~lylpoly~ei1- Y~ne having a ViSCG~i~y of 80,000 mm2/s, 44.0 parts of a,a~-di(trimethylsiloYy)-~ h~l-poly-cil~y~tne having a viscosi~y of 100 mm2/s, 11.0 parts of the SiH-rich partial hydrolysate, the ~re~a,~tion of which is described in Ex-ample 1 under (A), 0.44 part of oleic acid and 11 parts of ~.L~ho-bized ~y.o~nic silicic acid (commercially obtainable under the name WACKER HDK H15' from Wacker-C~hPmie GmbH) are mi~ed using a labol~toly mixer (Janke & Kt1nkPI RE 162). The compo~it~ t formed is kept for 30 minutes at a temperature of 50C with ~Ycl1~nnrt of air.
It is then evacuated under a pressure of 0.5 kPa for 5 ~uut~, while stirring.
The composition thus obtained is introduced into tubes and stored at 50C.
After preparation of the composition and af~er storage at 50C for 1, 3 and 6 months, a protion of the composition is spread to a film 2 mm thick and the time taken for a dry surface to form (skin formation time tH) and the me~hstnic~1 values of the elastomers are determined.
The res~lts are to be found in Table 4.

~148~65 Table 4 Storage t~ Shore Elonga- Tear M~ Te~r time [m1n] A tion at strength [N~m~] propa-[months] hard- break [N/Dm~] gation ~ess ~%~ refiis-tance . [N/m~]

0 9 27 330 l1.4 0.6 4.8 1 10 30 310 l1.4 0.6 5.0 3 ~ 20 '1.3 0.6 4.7 6 9 :_3 280 11.2 0.6 4.3 After storage of the composition at 50C for 7 weeks, an increas-ingly greater evolution of hydrogen was detecte~l from the rolled-up base of the tube, also leading to inclusions of gas bubbl in the lS composition after storage for 12 weeks.

Claims

1. Organopolysiloxane compositions which are storage stable in the absence of water but, on the addition of water, are crosslinked to elastomers even at room temperature with elimination of alcohols, and are prepared from (A) an .alpha.,.omega.-dihydroxyorganopolysiloxane, (B) an organosilicon compound of the formula HSi(OR)2O]a[HSi(OR)O]b[HSiO3/2]c[Si(OR)3O]d[Si(OR)2O]e[Si(OR)O3/2]f[SiO2]g[R1O]h (I), wherein R is identical or different and is a monovalent, optionally substi-tuted hydrocarbon radical or organosilicon radical, R1 is identical or different and is a divalent, optionally substituted organic radical and a, b, c, d, e, f, g and h are 0 or a number greater than 0, with the proviso that the content of Si-bonded hydrogen is 0.1% to 0.9% by weight, based on the total weight of the organosilicon com-pound of formula (I), and at least 20% of the number of radicals R in the organosilicon compound of formula (I) are a monovalent, option-ally substituted hydrocarbon radical, and optionally fillers, additives, catalysts, plasticizers, adhesion promoters and scavengers.

2. Organopolysilocane compositions according to Claim 1, wherein (A) is .alpha.,.omega.-dihydroxyorganopolysiloxane of the formula .alpha.,.omega.-dihydroxyorgano-polysiloxane of the formula (II) wherein R2 is identical or different, monovalent SiC-bonded organic radi-cals and n is a number of at least 20.

3. Organopolysiloxane compositions according to Claim 1, wherein R is monovalent, optionally substituted hydrocarbon radicals.

4. Organopolysiloxane compositions according to Claim 1, wherein R is a methyl, ethyl, n-propyl, iso-propyl radical or CH3OCH2CH2 radical.

5. Organopolysiloxane compositions according to Claim 1, wherein the content of Si-bonded hydrogen in the organosilicon compounds of formula (I) is 0.2% to 0.8% by weight, based on the total weight of the organosilicon compound of formula (I).

6. Organopolysiloxane compositions according to Claim 1, based on the total weight of organopolysiloxane compositions comprising, (A) 20% to 98% by weight of .alpha.,.omega.-dihydroxyorganopolysiloxane, (B) 1% to 50% by weight of organosilicon compound of formula (I), (C) 0% to 50% by weight of additives, (D) 0% to 70% by weight of filler, (E) 0% to 70% by weight of plasticizer, (F) 0% to 20% by weight of adhesion promoter, (G) 0% to 20% by weight of scavenger and (H) 0% to 10% by weight of condensation catalyst.

7. Organopolysiloxane compositions according to Claim 1, based on the total weight of the organopolysiloxane compositions comprising, (A) 30% to 70% by weight of .alpha.,.omega.-dihydroxyorganopolysiloxane, (B) 3% to 20% by weight of organosilicon compound of formula (I), (C) 1% to 7% by weight of additives, (D) 5% to 50% by weight of filler, (E) 10% to 50% by weight of plasticizer, (F) 1% to 8% by weight of adhesion promoter and (H) 0.1% to 3% by weight of condensation catalyst.

8. Organosilicon compounds of the formula [HSi(OR)2O]a'[HSi(OR)O]b'[HSiO3/2]c'[Si(OR)3O]d'[Si(OR)2)]e'[Si(OR(O3/2]f[SiO2]g[R1O]h' (I'), wherein R is identical or different and is a monovalent, optionally substi-tuted hydrocarbon radical or organosilicon radical, R1 is identical or different and is a divalent, optionally substituted organic radical and, a', b', c' d', e', f', g' and h' are 0 or a number greater than 0, with the proviso that the content of Si-bonded hydrogen is 0.1% to 0.9% by weight, based on the total weight of the organosilicon com-pound of formula (I), and at least 20% of the number of radicals R in the organosilicon compound of formula (I) are a monovalent, option-ally substituted hydrocarbon radical.

9. Process for the preparation of the organosilicon compounds according to Claim 8, comprising reacting an alcohol (1) with a partial hydro-lysate (2) of organyloxysilanes of the formula HSi(OR)3 (III) and optionally alkanediols, wherein R is identical or different and is a monovalent, optionally substi-tuted hydrocarbon radical.