CA2141985C - Process for the preparation of organopolysiloxanes containing organyloxy groups - Google Patents
Process for the preparation of organopolysiloxanes containing organyloxy groupsInfo
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- CA2141985C CA2141985C CA002141985A CA2141985A CA2141985C CA 2141985 C CA2141985 C CA 2141985C CA 002141985 A CA002141985 A CA 002141985A CA 2141985 A CA2141985 A CA 2141985A CA 2141985 C CA2141985 C CA 2141985C
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
- C08G77/06—Preparatory processes
- C08G77/08—Preparatory processes characterised by the catalysts used
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
- C08G77/14—Polysiloxanes containing silicon bound to oxygen-containing groups
- C08G77/16—Polysiloxanes containing silicon bound to oxygen-containing groups to hydroxyl groups
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
- C08G77/14—Polysiloxanes containing silicon bound to oxygen-containing groups
- C08G77/18—Polysiloxanes containing silicon bound to oxygen-containing groups to alkoxy or aryloxy groups
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
- C08G77/32—Post-polymerisation treatment
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Abstract
A process for the preparation of organopolysiloxanes which contain at least one unit of the formula (R10)3-mRmSiO1/2 in which R is identical or different and is a hydrogen atom or monovalent, optionally substituted hydrocarbon radical, R1 is identical or different and is a monovalent, optionally substituted hydrocarbon radical having 1 to 8 carbon atoms and m is 0, 1 or 2, which comprises, in a 1st step, reacting organosilicon compounds (1) which contain at least one Si-bonded hydroxyl group with at least one silane (2) of the formula (R1O)4-mSiRm and/or partial hydrolysates thereof, in which R, R1 and m have the above mentioned meaning, in the presence of a fluoride salt (3), and, optionally, in a 2nd step, when the reaction has ended, adding component (4) which can bond fluoride ions.
Description
214198~
Docket: WA 9343-S
Paper No. 1 PROCE~ FOR TH~: PREPARA'rIOII OF ORGAl~OPOLY~ILOXAI~I~
CONTAIl!II~IG ORGAIIYLOXY GROUP~3 Field of Invention The invention relates to a process for the preparation of organopoly-siloxanes containing organyloxy groups by reaction of hydroxysiloxanes with 0 organyloxysilanes, and the use thereof in compositions which can be cross-linked at room temperatures.
Back~round of Invention Processes for the preparation of organopolysiloxanes contz~inin~
organyloxy groups are already known. For ex~ple, U.S. 5,196,497 (Bayer AG, issued on March 23, 1993) and the corresponding EP 468 239 A2 describe the reaction of a,~-dihydroxypoly(diorganosiloxanes) with alkoxy-silanes in the presence of alkali metal hydroxides, which leads, by elimin5~-tion of alcohol, to the desired polysiloxanes blocked by end groups. The strong bases have a high equilibrating activity and, if the reaction time is too long or the temperatures relatively high often lead to an undesirably high content of monoalkoxy end groups which are not capable of crosslink-ing. Deactivation of the catalyst with strong acids, such as, chlorosilanes or phosphoric acid, must therefore be careried out at precisely the right time.
Since the reaction may occur literally within a minute, the time between addition of the catalyst and deactivation of the catalyst of ~veral minutes, customary during factory production, can result in a product which does not meet the specification. Furthermore, the amount of deactivating reagent should be precisely matched stoichiometrically to the amount of catalyst employed, in order to quarantee the storage stability of the end product. In practice, an excess of deactivating reagent will therefore often have to be employed. Since these are strong acids having an equilibrating activity, this excess must be removed from the product again.
U.S. 5,055,502 (Phone-Poulenc Chemie; issued on October 8, 1991) describes a process in which zinc chelate complexes effect the blocking of the ends of OH polymers with alkoxysilanes at relatively high temperatures.
DE 3428840 Al (General Electric Co.; published on February 21, 1985) and the col~esponding GB 2144758 A disclose aluminum chelate complexes which are employed as catalysts for alkoxy blocking of the ends of organo-polysiloxanes containing OH groups. In U.S. 5,166,296 (General Electric Co.; issued on November 24, 1992) and the corresponding EP 520 718 A2, the preparation of polysiloxanes blocked by alkoxy end groups from aL~coxy-nes and polysilox~qnes having terminal OH groups is car~ied out in the presence of catalytic amounts of ammonium salts of carboxylic acids.
Sllmm~t~r of Invention 0 The present invention relates to a process for the preparation oforganopolysiloxanes which contain at least one unit of the formula (RlO)3 mRmSiOl/2 (I) in which R is identical or different and is a hydrogen atom or monovalent, optionally substituted hydrocarbon radical, Rl is identical or different and is a monovalent, optionally substituted hydrocarbon radical having 1 to 8 carbon atoms and m is 0, 1 or 2, which comprises, in a 1st step, reacting org~nosilicon compounds (1) which 20 contain at least one Si-bonded hydroxyl group with at least one silane (2) of the formula (RlO)4 mSiRm (II) and/or partial hydrolysates thereof, in which R, R' and m have the above mentioned meaning, in the presence of a fluoride salt (3), and, optionally, in 25 a 2nd step, when the reaction has ended, adding component (4) which can bond fluoride ions.
The term organopolysiloxanes in the context of the present invention is also intended to include oligomeric siloxanes.
The radical R is preferably monovalent, optionally substituted hydro-30 carbon radicals having 1 to 13 carbon atoms, where the methyl, vinyl and3-(N-cyclohexylamino)propyl radical are more preferred.
Examples of the radical R are allcyl 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 r~ic~l~, such as the n-hexyl radical, heptyl radicals, such as the n-heptyl radical, octyl radicals, such as the n-octyl radical, and iso-octyl radicals, such as the 2,2,4-tri-methylpentyl radical, nonyl radicals, such as the n-nonyl radical, decyl radicals, such as the n-decyl radical, and dodecyl radicals, such as the n-dodecyl radical; aLt~enyl radicals, such as the vinyl and the allyl radical;
cycloaLtcyl radicals, such as cyclopentyl, cyclohexyl and cycloheptyl radicals and methylcyclohexyl radicals; aryl radicals, such as the phenyl and the naphthyl radical; aL~aryl radicals, such as o-, m- and p-tolyl radicals, xylyl radicals and ethylphenyl radicals; and araL~cyl radicals, such as the benzyl radical and the a- and ~-phenylethyl radical.
Examples of substituted hydrocarbon radicals are haloaLtcyl radicals, such as the 3,3,3-trifluoro-n-propyl radical, 2,2,2,2',2',2'-hexafluoroiso-propyl radical and the heptafluoroisopropyl radical; haloaryl r~-lic~l~, such as the o-, m- and p-chlorophenyl radical; the 3-thio-1-propyl radical;
acyloxyaL~cyl radicals, such as the acetoxyethyl radical and (meth)acryloylo~y~ropyl radical; and A
CH2-CH-CH2-0-CH2-, HSCH2-, H2NCH2-, 4,5-dihydroimi~1~701-l-yl-CH2-, imi~l~701-l-yl-CH2-, pyrrolidinyl-CH2-, piperidyl-CH2-, N-morpholinyl-CH2-, pipera_inyl-CH2-, cyclohexyl-NH-CH2-,H2N-CH2CH2-NH-CH2-, H2C=C(CH3)C00-CH2-, 2-cyanoethyl-, 3-cyanopropyl-, CH2-CH-CH2-0-(CH2)3-, HS(CH2)3-, H2N(CH2)3-, 4,5-dihydroimidazol-1-yl-(CH2~3-, imida_ol-l-ly-(CH2~3-, pyrrolidinyl-(CH2~3-. piperidyl-(CH2~3, N-morpholinyl-(CH2~3-, piperazinyl-(CH2~3-, cyclohexyl-NH-(CH2~3-, H2N-CH2-CH2-NH-(CH2)3- and H2C=C(CH3)C00-(CH2)3- radical.
Examples of the radical Rl are the examples of optionally substituted hydrocarbon radicals having 1 to 8 carbon atoms mentioned for R.
The radical Rl is preferably a methyl, ethyl, n-propyl, isopr< ~yl, pro-pen-2-yl, n-butyl, sec-butyl or iso-butyl radical, methyl and ethyl radicals being more preferred.
21419B~
The organosilicon compounds (1) cont~ining at least one Si-bonded hydroxyl group which are employed in the process according to the inven-tion are preferably those chosen from the group conci~ting of organopolysi-loxanes having at least one Si-bonded hydro~yl group, and organosilanes having a hydroxyl group.
The organosilicon compound (1) cont~ining at least one Si-bonded hydroxyl group which is employed in the process according to the invention can be any of the hydroxysiloxanes and monohydroxysilanes known to date.
The hydroxysiloxanes employed according to the invention can of course contain other units containing Si-bonded hydroxyl groups, such as (HO)2 ~R3~SiO2/2 and HOSiO3/2 units, in addition to units of the formula (HO)3 tR3,SiOl/2, in which R3 has one of the me~nin~ given for R1 t is 0, 1 or 2 and sis0 or 1.
Ex~mples of the organosilicon compound (1) employed according to the invention are a,Q)-dihydroxydiorganopolysiloxanes, such as HOMe2Si(OSiMe2)l to looooOH and HOMe2Si(OSiMe2)0 to lOOOO(OSiMeVi)o to looooOH, where this siloxane cont~ s at least two silicon atoms, a-monohydroxydiorganopolysiloxanes and monohy-droxysilanes, such as Me3Si(OSiMe2)0 ~ looooOH, HMe2Si(OSiMe2)~ ooooOH, (H2C=CH)Me2Si(OSiMe2)0 to looooOH and (H2C=CHCH2)Me2Si(OSiMe2)0 to looooOH, where Me is the methyl radical and Vi is the vinyl radical, and branched hydroxy-functional organopolysilox-anes and hydroxy-functional organopolysiloxane resins, such as described in EP 540 039 Al (Dow Corning Japan Ltd.), column 5, lines 37 to 40 and column 6, line 25, the olg~lyl r~-lic~ preferably being methyl r~tlic~
Fur~er examples are organosilicon compounds of the above mentioned type which contain hydroxyl groups and, in addition to methyl groups, also con-tain phenyl groups, vinyl groups, l-thio-3-propyl groups or 3,3,3-trifluoro-propyl groups.
The hydroxysiloxanes (1) employed according to the invention have a viscosity at 25~C of preferably 1 to 106 mm2/s, more preferably 10 to 5 x 105 mm2/s.
214198~
The organosilicon compounds (1) employed according to the invention are more preferably a,~-dihydroxyldiorganopolysiloxanes.
The organosilicon compounds which contain hydroxyl groups and are employed according to the invention can be one type of such organosilicon 5 compounds or a mixture of at least two different types of organosilicon com-pounds.
The organosilicon compounds which contain hydroxyl groups and are employed according to the invention are commercially available products or can be prepared by processes customary in silicone chemistry.
Examples of the silanes (2) employed according to the invention are Si(OCH3)4, Si(OCH2CH3)4, H3CSi(OCH3)3, CH3Si(OCH2CH3)3, H2C=CH-Si(OCH3)3, H2C=CH-Si(OCH2CH3)3, C6Hs-Si(OCH3)3, (H3C)2Si(OCH3)2, HSi(OCH2CH3)3, F3CCH2CH2Si(OCH3)3, H2C=CH(CH2)4-Si(OCH3)3, N_C-CH2CH2-Si(OR')3, N-C-CH2CH2CH2-Si(OR')3, and XCH2CH2CH2Si(ORI)3 where X is ~O
CH2-CH-CH2-O-, HS-, H2N-, 4,5-dihydroimi~1~7ol-l-yl, imidazol-l-yl, pyrrolidinyl-, piperidyl-, N-morpholinyl-, piperazinyl-, cyclo-hexyl-NH-, H2N-CH2CH2-NH-, or H2C=C(CH3)COO- radical and Rl has the above mentioned me~ning. Some of these silanes also react with OH-func-tional organosilicon compounds even in the absence of catalysts. In such cases, reaction times can be shortened and/or reaction temperatures low-ered by the process according to the invention, which can bring advantages during further proces~ing of the products.
The silanes (2) employed according to the invention are preferably Si(OCH3)4, Si(OCH2CH3)4, H3CSi(OCH3)3, CH3Si(OCH2CH3)3, H2C=CH-Si(OCH3)3, H2C=CH-Si(OCH2CH3)3, N=C-CH2CH2Si(OCH2CH3)3, 4,5-dihydroimi-1~7.ol- l-yl-CH2CH2CH2SitOCH2CH3)3, (~2-CH-CH2-O-CH2CH2CH2Si(OCH3)3, H2C=C(CH3)COOCH2CH2CH2-Si(OCH3)3, cyclohexyl-NH-CH2CH2CH2-Si(OCH3)3, H2N-CH2CH2-NH-CH2CH2CH2-Si(OCH3)3, HS-CH2CH2CH2-Si(OCH3)3 and N-morpholinyl-CH2CH2CH2-Si(OCH3)3, where H3CSi(OCH3)3, CH3Si(OCH2CH3)3, H2C=CH-Si(OCH3)3, H2C=CH-Si(OCH2CH3)3, N-C-CH2CH2Si(OCH2CH3)3, 4,5-dihydroimiti~7~0l-l-yl-CH2CH2CH2Si(OCH2CH3)3 and cyclohexyl-NH-CH2CH2CH2-Si(OCH3)3 are more preferred.
The silanes (2) employed according to the invention can be a single type or a mixture of at least two different types of such silanes or partial hydrolysates thereof.
If partial hydrolysates of the silanes (2) are employed in the process 0 according to the invention, these are preferably those which are liquid at room te~ ature.
The silanes (2) employed according to the invention or partial hydro-lysates thereof are commercially available products or can be prepared by processes customary in silicone chemistry.
The silane (2) and/or partial hydrolysate thereof is advantageously employed in the process according to the invention in a stoichiometric excess with respect to Si-bonded hydroxyl groups. The silane (2) and/or partial hydrolysate thereof is preferably employed in amounts of 1.0l to 20 mole per mole of Si-bonded hydroxyl groups of the compound (1), more preferably 1.01 to 10 mole per mole of Si-bonded hydroxyl groups of the compound (1). Higher excesses can be favorable if the preparation of com-positions based on the ol~.yloxysiloxanes prepared according to the in-vention which can be crosslinked by moisture at room temperature and in which the excess organyloxysilane serves as the cros~1inking agent is desired. Under certain circumstances, a further metering operation thus becomes superfluous, which can have an advantageous effect in particular during continuous preparation of RTV- 1 compositions.
The fluoride salt (3) employed in the process according to the inven-tion is preferably one chosen from the group consisting of ammonium fluo-rides of the formula [R24N]F (III) in which R2 can be identical or different and has one of the me~nings {pven f~r R, adducts thereof with carbonyl compounds, such as ~-ketocarboxylic 214198~
acid esters of 1,3-diketones, (alkali) metal fluoAdes, such as potassium fluoride, cesium fluoride, zinc fluoride, dibutyltin fluoride and copper fluo-ride, and organic or inorganic ammonium hydrogen fluorides, phosphonium fluorides, phosphonium hydrogen fluorides, tetratluoroborates, hexafluoro-silicates and fluorophosphates.
The radical R2 is preferably the methyl, ethyl, n-butyl, n-propyl, iso-propyl or the benzyl radical, where the methyl, n-butyl and benzyl radical are more preferred.
The fluoride salt (3) employed in the process according to the inven-tion is more preferably ammonium fluoride of the formula (III).
Examples of the fluoride salt (3) are l(H3C(CH2)3)4N]F (called TBAF
below), l(H3C)4NlF, lC6H5CH2-N(CH3)3]F and [H3CNH3]F and adducts thereof with carbonyl compounds, where acetylacetone, methyl acetoacetate, 2-ethylhexyl acetoacetate and isopropyl acetoacetate are preferred and acetylacetone and ethyl acetoacetate are more preferred as the carbonyl compound.
Fluoride salts are commercially available products or can be prepared by processes customary in organic chemistry. Reference may be made for example to, Clark, J.H., Miller, J.M. in J. Chem. Soc., Perkin Trans.I, 1977, 1743- 1745.
The fluoride salts (3) employed according to the invention can be a single type or a mixture of at least two different types of such fluoride salts.The fluoride salt (3) can be employed in the process according to the invention as a mixture with organic solvents and/or organosilicon com-pounds or in a form fixed to support materials, such as silicic acid, ion exch~nger resin, titanium dioxide or aluminum oxide. Processes for the preparation of fluoride salt bonded to a support material are described, for example, in Gambacorta, ~, Turchetta S., Botta, M., Synth. Commun., 1989, 19 (13-14), 2441-2448; Li, C., Lu, Y., Huang, W., He, B., Synth.
Commun., 1991, 21(12-13), 1315-1320.
All the known organic solvents which have no interfering effect on the reaction procedure can be employed as solvents; the solvents are preferably 21~198~
_ organic solvents, which can easily be removed from the end product by ~olation. Examples of such solvents are diethyl ether, dibutyl ether, tetrahydrofuran, dioxane, hexane, toluene, xylenes, chlorobenzene, 1,3-pentanedione, acetone, methyl t-butyl ketone, methyl ethyl ketone, 5 1,2-dimethoxyethane, acetonitrile, ethyl acetate, methyl acetate, butyl ace-tate, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, methanol, ethanol, n-propanol, 2-propanol, n-butanol, 2-butanol and isobutanol and mixtures of these solvents.
The fluoride salt (3) can also be employed in the process according to lO the invention as a mixture with organosilicon compounds, such as silanes or oligomeric or polymeric siloxanes.
In the ple~alation of mixtures which can be crosslinked by moisture at room temperature after the preparation according to the invention of the organyloxysiloxanes in particular it is advantageous to dissolve the fluoride l5 salt (3) in the organyloxysilanes to be reacted, if api)ro~,iate with the addi-tion of the corresponding free compound RlOH, where Rl has the above mentioned meaning, or in another liquid constituent, such as OH-cont~ining polysiloxane or a poly(diorganosiloxane) blocked by end groups, which is often employed as plasticizer, such as (H3C)3SiO-[Si(CH3)20]70-Si(CH3)3, an 20 oligomeric siloxane, such as (H3C)3SiOSi(CH3)3, or a cyclosilox~ne, such as Si(CH3)20]4.
Both the adducts with carbonyl compounds and the ammonium fluorides adsorbed onto support materials often have the advantage that they are less hygroscopic and therefore have a better storage stability than 25 the pure ammonium fluorides.
The fluoride salt (3) is employed in the process according to the invention in amounts of preferably 0.1 to 1000 ppm (parts by weight per million parts by weight), more preferably 1 to 100 ppm, in each case calcu-lated as elemental fluorine and based on the total weight of organosilicon 30 compound (1). The amount of fluoride salt (3) to be employed depends in particular on the reactivity of the individual reaction partners and on the presence of constituents which accelerate or retard the reaction, such as compounds having acid or basic radicals or fluoride-bonding constituents.
The conditions under which the process according to the invention can be catried out primarily depend on the reactivity of the olg~-yloxysilane (2) employed and on the nature and concentration of the fluoride salt ~3).
The process according to the invention is carried out at temperatures of preferably 20~ to 100~C under a pressure of preferably 900 to 1100 hPa.
However, it can also be carried out at higher or lower temperatures and un-der higher or lower pressures.
In most cases, the process according to the invention can be carried out at room temperature. However, it may be advantageous, for example, if a lower viscosity of the reaction mixture is required for technical reasons, to carry out the reaction at elevated temperature; in this case acceleration of the reaction is in general to be expected under otherwise the same condi-tions.
The end of the reaction according to the invention can be detected by lS measuring the SiOH content in the reaction mixture by means of IR spec-troscopy, 29Si-NMR or lH-NMR spectroscopy or by a cros~linking test to detect residual SiOH functions in polysiloxanes, such as by the cros~linking test according to EP 468 239 A2 cited above, or by addition of aluminum tri-sec-butylate; an immediate increase in viscosity, under certain circum-stances up to gelling, indicates residual SiOH groups and therefore incom-plete co.lversion.
When the reaction according to the invention has ended, the fluoride salt (3) is preferably deactivated by addition of component (4), which can bond fluoride ions, the aim being to suppress further unwanted reactions and to ensure that the organopolysiloxanes which contain organyloxy groups and are prepared according to the invention do not change during storage.
Examples of component (4) are aluminum compounds and com-plexes, such as aluminum alcoholates, pyrogenically produced or precipi-tated silicic acid, calcium-cont~ining fillers, which are suitable for deactiva-tion of component (3) because of the high tendency towards formation of calcium fluoride, such as calcium carbonate, calcium silicate, calcium phosphate and chalks whose surface has been treated with carboxylic acids 214198~
such as 2-ethylhexanoic acid (so-called coated chaL~s), and mixtures thereof.
Aluminum compounds or complexes are preferably employed as component (4) in the process according to the invention.
Examples of compounds and complexes of aluminum are aluminum carboxylates, aluminum thiolates, aluminum sulfonates, aluminum phos-phonates, aluminum amides, aluminum sil(ox)anolates, aluminum halides, aluminum alcohol~tes and aluminum alcoholates in which one or more a~coxy radicals can be replaced by ~-dicarbonyl chelating ligands, for ex-0 ample Al[OCH2CH3l3, Al[OCH(CH3)(C2Hs)]3, Al[OCH(CH3)2]3, AllH3C-C(O)CHC~O)-CH3]3, AllOCH(CH3)2]2lH3CC(O)CHCOOCH2CH3], alumi-num complexes according to formula (4) of DE 34 28 840 Al cited above, such as aluminum di(methoxy)ethylacetoacetonate, aluminum methoxy-di(ethylacetoacetonate), aluminum di(isopropoxy)acetylacetonate, aluminum isopropoxy-di(acetylacetonate), aluminum isopropoxy-di(ethylacetoace-tonate), aluminum bis(trimethylsiloxy)ethylacetoacetonate, aluminum bis(dimethoxymethylsiloxy)ethylacetoacetonate, aluminum bis(dimethoxy-methylsiloxy)acetylacetonate, aluminum tri(ethylacetoacetonate), aluminum bis(dimethylamino)ethylacetoacetonate, aluminum 1,3-propanedioxyethyl-acetoacetonate and aluminum di(isopropoxy)(methylsalicylate), and reaction products of aluminum alcoholates and organyloxysilanes of the formula III), such as di-sec-butoxyaluminoxytriethoxysilane and the reaction product of aluminum di(isopropoxy)-ethylacetoacetonate and tetraethoxysilane.
An aluminum alcoholate is more preferably employed as component (4) in the process according to the invention.
Component (4) employed according to the invention can be a single type or a mixture of at least two different types of such components (4).
The aluminum compounds and complexes employed as component (4) are commercially available products or can be prepared by processes customary in chemistry.
The aluminum compound or complex (4) can be employed in the process according to the invention as a mixture with organic solvents and/or organosilicon compounds, which is preferred.
Solvents and organosilicon compounds which can be employed are the same as those which were described above in connection with the fluo-ride salt (3), the aluminum compound or complex ~4) preferably being employed as a mixture with tetrahydrofuran and/or polydiorganosiloxanes, such as (H3C)3SiO[Si(CH3~2l70-Si(CH3)3, (H3C)3SiOSi(CH3)3 and ¦Si(CH3)2O]4.
At least a stoichiometric equivalent of aluminum in the form of the aluminum compound or complex ~4) with respect to the fluoride is prefera-bly added in the deactivation step acco~ding to the invention. The alumi-num compound or complex (4) is more preferably employed in amounts of 1.05 to 3 mole of aluminum per mole of fluoride of component (3).
The process according to the invention can be car~ied out continu-ously or discontinuously.
The elimin~tion of the organopolysiloxanes according to the invention cont~inin~ organyloxy groups after the reaction according to the invention or after the deactivation step according to the invention can be carried out by any desired and known methods. For example, after the deactivation step according to the invention, the excess organyloxysilane (2), the compound RlOH liberated as a cleavage product, where R' has the above mentioned me~ning, and other possible cleavage products and solvents can be removed by thorough heating and/or by reducing the pressure.
The organopolysiloxanes which contain organyloxy groups and are prepared according to the invention can be employed for all purposes for which organopolysiloxanes having organyloxy groups have also been employed such as, for co~hngs to improve the water-repellent properties of substrate surfaces, as an adhesion promoter additive, as a primer, for adhesives, for tex~le coatings, for plasticizers (which can be crosslinked in ifthe siloxane is blocked by organyloxy at only one end) and as a base poly-mer in organopolysiloxane compositions which can be cros~linked by mois-ture, in particular RTV-l compositions.
Organopolysiloxane compositions which can be cross1inked by mois-ture and processes for their preparation are generally known. They essen-tially comprise base polymer, vll1c~ni7~hon catalysts, cros~linking agents . 2141985 and, optionally, plasticizers (in general silicone oils which are blocked with non-reactive end groups), fillers, adhesion promoters and stabilizers.
For certain intended uses of the organopolyci10~c~nes which contain organyloxy groups and are prepared according to the invention, in particu-5 lar for their use in compositions which crosslink by means of moisture, thereaction composition obt~ined according to the invention can be employed without ~limin~ti~n of the organopolysiloxane which contains organyl groups. In this case, an excess of the silane (2) employed in the process according to the invention can serve as the cros~1inking agent. If pyrogenic 0 silicic acid is employed as a constituent, the amount of aluminum com-pound can be greatly reduced proportionally, or its use can be dispensed with entirely, because of the high adsorptive bonding of fluoride ions onto the silicic acid surface.
It is essential, for the stability of the compositions which can be 5 crosc1ink~d by means of moisture, only that complete reaction of the hydroxyl groups of the organosilicon compound (l) with the organyloxy-silane (2) has taken place before addition of the pyrogenic silicic acid. This applies to calcium-cont~ining fillers or additives, which are suitable for the deactivation because of the high tendency toward the formation of calcium 20 fluoride.
If use of the polysiloxanes prepared by the process according to the invention in organopolysiloxane compositions which cure by means of moisture is intended, the process according to the invention can also be carried out as a one-pot process or continuously in the mixin~ unit envis-25 aged for preparation of the compositions which cros~link by means ofmoisture. In the latter case, the fluoride salts (3) and the deactivating rea-gents (4) can be combined with the reaction medium in static mixer systems with the aid of metering pumps.
The process according to the invention has the advantage that 30 organopolysiloxanes cont~ining organyloxy groups can be prepared in a simple manner and selectively with a high rate of reaction.
The fluoride component (3) employed according to the invention has the advantage that it has a highly accelerating action on the reaction accord-ing to the invention and has only a moderate equilibrating activity.
If component (4) is added, there is a further advantage in that by the S deactivation step with aluminum alcoholates carried out according to theinvention, storage-stable end products are accessible without an after-treatment step, even if the deactivating aluminum compound is employed in a small stoichiometric excess.
In the examples described below, all parts and percentage data relate 0 to the weight, unless stated otherwise. Furthermore, all the viscosity data relate to a temperature of 25~C. Unless stated otherwise, the following examples were carried out under a pressure of the surrounding atmosphere at about 1000 hPa and at room te~l~elature at about 20~C, or a tempera-ture which is established when the reactants are brought together at room temperature without additional heating or cooling.
TBAF represents tetra-n-butylammonium fluoride THF represents tetrahydrofuran E~ample 1 A Preparation of the aluminum component A mixture of 27.6 g of water and 230 g of THF is added to a solu-tion of 210 g of aluminum di(isopropoxy)-acetoacetic ester chelate (=Al[O-CH(CH3)2]2[H3C-C(O)CHC(O)OC2Hsl) and 319 g of tetraethoxy-silane in 766 g of THF at room temperature in the course of 30 min-utes. The mixture was then heated under reflux for one hour.
Thereafter, all the volatile constituents were stripped off at room tem-perature under 3 hPa. After filtration, 344 g of a clear oily liquid, the aluminum content of which was 3.9% by weight, were obtained.
A mixture of 2000 g of a polydimethylsiloxane having OH end groups and a viscosity of 1000 mm2ts with 145 g of methyl-trimethoxysilane was prepared in a planetary mixer. 4.3 ml of 1.1 M
solution of TBAF in THF were stirred into this mixture (=0.0047 mole of F; 45 ppm of F, based on the weight of hydroxysiloxane). After 25 minutes, 7.74 g of a solution of 3.87 g of the aluminum component '_ described under A) in 3.87 g of mel~lylL,i~ethoxysilane were added (=0.0056 mole of A1). After the components had been mixed thor-oughly for 5 minutes, a 29Si-NMR spectrum and a gel permeation chromatogram of the reaction mixture were recorded. It was found that all the OH end groups had been replaced by H3CSi(OCH3)2-O-end groups. Gel permeation chromatography showed a molecular size distribution (excluding the excess methyltrimethoxysilane) which corresponded to that of the OH group-cont~ining polymer employed.
E~ample 2 1.3 ml of 1.1 M solution of TBAF in THF were added to a mixture of 150 g of polydimethylsiloxane having OH end groups and a viscosity of 70 mm2/s and 48.96 g of methyltrimethoxysilane (0.0014 mole of F, 181 ppm of F, based on the weight of hydroxysiloxane). After 20 minutes, the catalyst was deactivated by addition of 2.6 ml of a 50%
strength solution of the aluminum component described in Example 1 under A) in methhyltrimethoxysilane ~0.0019 mole of Al). The volatile constituents were then distilled off up to 80~C/ 12 hPa. 155 g of a clear colorless oil remained as the residue, the average formula of which was obtained from the 29Si-NMR spectrum:
MeSi(OMe)2-(SiMe20)44-Si(OMe)2Me.
Comparison Example 1 0.55 ml of a 10% strength solution of aluminum tri-secbutylate in THF was added to a mixture of 100 g of a polydimethylsiloxane hav-ing OH end groups and a viscosity of 1000 mm2/s and 14.8 g of methyltrimethoxysilane, after which the formation of gelatinous regions occurred suddenly, which is to be interpreted as an indication of incomplete saturation of the Si-OH groups of the polydimethylsi-loxane having OH end groups. In addition to me~ imethoxysilane and the dimethylsiloxy units of the OH-polymer, only HO-Si(CH3)2-O-and no H3CSi(OCH3)2-O- end groups were detectable in the 29Si-NMR
spectrum.
~:xample 3 A mixture of 2000 g of a polydimethy~ ox~ne having OH end groups and a viscosity of 1000 mm2/s with 145 g of mell~yllli-methoxysilane was prepared in a planetary mixer. 4.3 ml of a 1.1 M
s solution of TBAF in THF were stirred into this mixture (= 0.0047 mole of F; 45 ppm of F, based on the weight of hydroxysiloxane). After storage at 25~C for two days, products of polymer degradation reac-tions (equilibration) were detected from the 29Si-NMR spectrum: the content of monomethoxy end groups, which are not capable of 0 crosslinking, was 20 mole %, based on all the end groups (80 mole %
of H3CSi(OCH3)2 end groups); the chain lengthening content of Si~CH3)0CH3-groups incorporated, was the same size.
Dimethyldimethoxysilane was also detectable.
E~ample ~
5 B Preparation of catalyst solution F
150 ml of 4% strength hydrofluoric acid were added to 195 ml of a 40% strength aqueous solution of tetra-n-butyl-ammonium hydroxide. The pH of the solution was 7. After addition of 60 g of 2,5-pentanedione, all the volatile constituents were distilled off on a rotary evaporator at 40~C/ 1 hPa. 5.5 g of the solid residue were dis-solved in 30 ml of methyltrimethoxysilane. A clear red-brown solu-tion having a nuoride content of 0.014 g/ml was obtained.
0.1 ml of the catalyst solution F described above under (B) was added to a mixture of 100 g of polydimethylsiloxane having OH end groups and a viscosity of 1000 mm2/s and 7.4 g of methyltrimethoxy-silane (=0.000074 mole of F; 14 ppm of F, based on the weight of hydroxysiloxane~ and the mixture was stirred for 20 minutes. The catalyst was deactivated by addition of 0.55 ml of a 10% strength solution of aluminum tri-sec-butylate in THF (0.000223 mole of Al).
As a cros~linkin~ test showed (addition of aluminum tri-sec-butylate to small samples taken from the reaction mixture after certain inter-vals of time), all the SiOH groups had reacted in the desired sense after only 15 minutes (no further gelling with aluminum tri-sec-butylate). It was to be seen from the 29Si-NMR spectrum that aU the OH end groups had been converted into H3CSi(OCH3)2- end groups.
E~ample 5 The procedure described in Example 4 was repeated with the modi-fication that, instead of 0.1 ml, 0.2 ml of catalyst solution F
l= 0.000147 mole of F; 28 ppm of F, based on the weight of hydroxy-siloxane) was added. From the crosslinking test for residual SiOH, it was found that the reaction had already ended after 10 minutes.
Nevertheless, deactivation with the aluminum component was carried 0 out only after 20 minutes. The 29Si-NMR spectrum was identical to that from Example 4.
Example 6 The procedure described in Example 4 was repeated, with the modification that inete~l of 0.1 ml, 0.3 ml of catalyst solution F
(= 0.00022 mole of F; 42 ppm of F, based on the weight of hydroxysi-loxane) was added. It was found from the croselinking test for resid-ual SiOH that the reaction had already ended after 5 minutes. Never-theless, deactivation with the aluminum component was carried out only after 20 minutes. The 29Si-NMR spectrum was identical to that from Example 4.
The 29Si-NMR spectrum of a sample which had been subjected to storage under heat in a closed polyethylene bottle in a drying cabinet at 80~C for 7 days, showed no change compared with the starting spectrum.
E~ample 7 The procedure described in Example 5 was repeated, with the modification that instead of 0.2 ml of catalyst solution F as described in Example 4 under B), 0.2 ml of a 1.1 M TBAF solution in THF
(0.00022 mole of F) was added. After 20 minutes, deactivation was carried out with 1.1 ml of a 10% strength solution of aluminum tri-sec-butylate in THF ~0.00045 mole of Al). The 29Si-NMR spectrum was identical to that of Example 5.
The 29Si-NMR spectrum of a sample which had been subjected to storage under heat in a closed polyethylene bottle in a drying cabinet at 80~C for 7 days showed no change compared with the initial spec-trum.
E~ample 8 The procedure described in Example 7 was repeated, with the modification that after 20 minutes the deactivation was carried out with 2.2 ml in~te:~tl of 1.1 ml of a 10% strength solution of aluminum tri-sec-butylate (0.00089 mole of Al). The 29Si-NMR spectrum was identical to that of Example 5.
The29Si-NMR spectrum of a sample which had been subjected to storage under heat in a closed PE bottle in a drying cabinet at 80~C
for 7 days showed no change compared with the starting spectrum.
Compllrison E~mple 2 A mixture of 0.2 ml of a 1.1 M solution of TBAF in THF (0.00022 mole of F) and 0.6 ml of a 10% strength solution of aluminum tri-sec-butylate in THF (0.00024 mole of Al) was added to a mixture of 100 g of a polydimethylsiloxane having OH end groups and a viscosity of 1000 mm2/s and 10 g of methyltrimethoxysilane. It was found from the 29Si-NMR spectrum of the reaction mixture that no reaction had taken place.
E~ample 9 0.2 ml of a 1.0 M solution of TBAF in THF was added to a mixture of 100 g of a polydimethylsiloxane having OH end groups and a vis-cosity of 1000 mm2/s and 12.7 g of 3-glycido~y~ropyltrimethoxy-silane (H2C(O)CHCH20(CH2)3-Si(OCH3)3 (0.0002 mole of F, 38 ppm of F, based on the weight of hydroxysiloxane). After 45 minutes, deacti-vation was carried out with 0.55 ml of a 10% strength solution of aluminum tri-sec-butylate in THF (0.00022 mole of Al). It was found in the 29Si-NMR spectrum of the mixture that all the SiOH functions had been converted into Si-OSi(OCH3)2-(CH2)3-OCH2-CH(O)CH2. The excess silane employed could be removed by thorough heating at 1 10~C/0. 1 hPa on a thin film evaporator.
Example 10 0.2 ml of a 1.0 M solution of TBAF in THF was added to a mixture of 100 g of a polydimethyl~ilox~ne having OH end groups and a vis-cosity of 1000 mm2/s and 13.4 g of 3-methacryloylo~y~royyl~i-methoxysilane (H2C=C(CH3)COO(CH2)3-Si(OCH3)3) (0.0002 mole of F, 38 ppm of F, based on the weight of hydroxysiloxane). After 25 min-utes, deactivation was carried out with 0.55 ml of a 10% strength solution of aluminum tri-sec-butylate in THF (0.00022 mole of Al).
It was found in the 29Si-NMR spectrum of the mixture that all the 0 SiOH functions had been converted into Si-OSi(OCH3)2-(CH2)3-OOC(CH3)C=CH2. The excess silane employed could be removed by thorough heating at 110~C/0.1 hPa on a thin film evaporator.
Example 11 0.2 ml of 1.1 M solution of TBAF in THF was added to a mixture of 100 g of a polydimethylsiloxane having OH end groups and a viscos-ity of 1000 mm2/s and 14.2 g of 3-(N-cyclohexylamine)plo~yl~
methoxysilane (cyclohexyl-HN-(CH2)3-Si(OCH3)3) (0.00022 mole of F>
42 ppm of F, based on the weight of hydroxysiloxane). After 15 minutes> deactivation was carried out with 0.22 g of the aluminum component described in Example 1 under A) (0.0003 mole of A1). It was found in the 29Si-NMR spectrum of the mixture that all the SiOH
functions had been converted into Si-OSi(OCH3)2-(CH2)3-NH~cyclo-hexyl).
Example 12 0.2 ml of a 1.0 M solution of TBAF in THF was added to a mixture of 100 g of a polydimethylsiloxane having OH end groups and a vis-cosity of 1000 mm2/s and 8.9 g of triethoxysilane (0.0002 mole of F>
38 ppm of F> based on the weight of hydroxy~ilo~c~ne). After 15 min-utes> deactivation was carried out with 0.55 ml of a 10% strength solution of aluminum tri-sec-butylate in THF (0.00022 mole of Al). It was found in the 29Si-NMR spectrum of the mixture that all the SiOH
functions had been converted into Si-OSiH(OCH2CH3)2.
_ 214198S
Example 13 0.2 ml of a 1.0 M solution of TBAF in THF was added to a mixture of 100 g of a polydimethylsiloxane having OH end groups and a vis-cosity of 1000 mm2/s and 6.5 g of dimethyldimethoxysilane (= 0.0002 mole of F, 38 ppm of F, based on the weight of hydroxysi-loxane). After 15 minutes, deactivation was carried out with 0.55 ml of a 10% strength solution of aluminum tri-sec-butylate in THF
(0.00022 mole of A1). It was found in the 29Si-NMR spectrum of the mixture that all the SiOH functions had been converted into Si-OSi(CH3)20CH3.
Example 14 1 ml of a 1.0 M solution of TBAF in THF was added to a mixture of 50 g of a branched polydimethylsiloxane having OH end groups and the average composition [HOSi(CH3)201/2l4-[Si(CH3)20l;,2¦SiO2ll 2 (prepared by gentle hydrolysis of a reaction product, prepared in the presence of PNC12, SiClq and a polydimethylsiloxane having OH end groups and a viscosity of 5 Pas) and 35.4 g of methyltrimethoxysilane (= 0.001 mole of F, 380 ppm of F, based on the weight of hydroxysi-loxane). After 10 minutes, deactivation was carried out with 2.7 ml of a 10% strength solution of aluminum tri-sec-butylate in THF
(0.001 mole of Al). It was found in the 29Si-NMR spectrum of the mixture that all the SiOH functions had been converted into Si-OSi(CH3)2CH3.
Example 15 0.2 ml of a 1.0 M solution of TBAF in THF was added to a mixture of 100 g of a polydimethylsiloxane having OH end groups and a vis-cosity of 1000 mm2/s and 7.4 g of methyltnmetho~silane at 75~C
(= 0.0002 mole of F, 42 ppm of F, based on the weight of hydroxysi-lo~ane). After 4 minutes, cros~linkin~ test on SiOH (aluminum sec-butylate) indicated complete co~ sion. Deactivation wa subse-quently carried out with 0.55 ml of a 10% strength solution of alumi-num tri-sec-butylate in THF (0.00022 mole of Al). It was found in the 29Si-NMR spectrum of the mixture that all the SiOH functions had been converted into Si-OSi(OCH3)2CH3.
Comparison E~cample 3 2 g of a solution of 2 g of NaOH in 47.5 of tetraethoxysilane and 0.5 g of ethanol (= 0.002 mole of NaOH) were added to a mixture of 163 g of a polydimethylsiloxane having OH end groups and a viscos-ity of 1000 mm2/s and 24.5 g of tetraethoxysilane. After 15 minutes, the base was neutralized with 0.2 g of dimethyldichlorosilane (= 0.0031 mole of Cl). All of the volatile components were subse-quently stripped off at 50~C/2 hPa. It was found in the 29Si-NMR
spectrum of the mixture, recorded after three days, that all the SiOH
functions had been converted into Si-OSi(OCH2CH3)3.
Comparison E~ample 4 Comparison Example 3 was repeated, with the difference that the volatile constituents were not distilled off after the neutr~li7~tic~n. It was found in the 29Si-NMR spectrum of the mixture recorded after three days that the desired triethoxysilyl end groups were present only in traces, and instead Si-OSi(CH3)2(0CH2CH3) functions which were not capable of crosslinking were chiefly detectable.
Example 16 A mixture of 90.9 g of melhylL,illlethoxysilane and 2.7 ml of 1.1 M
solution of TBAF in THF was added to 1000 g of a polydimethylsilox-ane having OH end groups and a viscosity of 80 Pas (0.003 mole of F, 56 ppm of F, based on the weight of hydroxysiloxane) in a planetary mixer. The mixture was stirred at room temperature for 25 minutes before deactivation was carried out with 24.3 g of a 10% strength solution of aluminum tri-sec-butylate in a polytdimethylsiloxane) blocked by trimethylsilyl end groups (= 0.01 mole of A1) which had a viscosity of 100 mm2/s. 524 g of this polydimethylsiloxane having trimethylsilyl end groups, 72.7 g of hexamethyl~ 7~ne, 254.4 g of a hydrophobic, pyrogenic silicic acid having a specific surface area of 120 m2/g and 4.91 g of dibutyltin diacetate were then mixed in suc-cession. Half of the paste obtained was cured in air in a layer thick-ness of 2 mm at room temperature for 14 days. An elastic vulcani-zate which gave the following mechanical values was obtained:
Tear strength (DIN 53504): 0.9 N/mm2 Elongation at break (DIN 53504): 340%
Tensile stress at 100% elongation (DIN 53504): 0.2 N/mm2 Tear propagation resistance (ASTM D 624 B-91): 4.3 N/mm2 Hardness (Shore A) (DIN 53505): 17 To investig~te the storage stability, the other half of the paste was protected from access of atmospheric humidity in polyethylene car-tridges. After storage at 50~C for 3 weeks, the paste showed no crosslinking phenomena when spread out, but then cured to an elastomer under the influence of atmospheric moisture.
Comparison Example 5 - (analogous to Example 1 of EP 468239 A2 cited above) 0.9 g of a solution of 2 g of NaOH in 47.5 g of melhyll,.~ethoxy-silane and 0.5 g of methanol (= 0.0009 mole of NaOH) was added to a mixture of 145 g of a polydimethylsiloxane having OH end groups and a viscosity of 1000 mm2/s (about 0.0178 mole of OH) and 10 g of methyltrimethoxysilane (0.0735 mole). After 5 minutes, the base was neutralized with 0.73 g of a solution of 5 g of dimethyldichlorosilane in 45 g of hexamethyldisiloxane (= 0.0011 mole of Cl). The mixture was then heated thoroughly at 140~Ct25 hPa for 2 hours. 132 g of a cloudy oil having a viscosity of 979 mm2/s remained as the residue.
The following average formula was obtained from the 29Si-NMR spec-trum of the product:
[MeSi(OMe)2Ol/2)2[SiMe2O]220. Blocking of the SiOH end groups was complete.
Compari~on E~ample 6 The procedure described in Comparison Example 5 was repeated, with the modification that the base was neutralized only after 10 minutes. 138 g of a cloudy oil having a viscosity of 427 mm2/s were obtained as the end product. The following average formula was 21~1985 obtained from the 29Si-NMR spectrum of the product:
[MeOSiMe2O~/2]2[Me(MeO)SiO][MeSiO3/2]05[SiMe2O]l,O. Although the blocking of SiOH end groups was complete, rearrangements to an extent such that the desired MeSi(OMe)2 end group was present only in traces had already taken place by lengthening the reaction time by 5 minutes compared with Comparison Example 5.
E~ample 17 C Preparation of catalyst solution F1 60 ml of 25% strength sulfuric acid were added to a solution of 17.4 g of potassium fluoride in 30 ml of completely demineralized water. After 30 minutes neutralization was carried out with 180 ml of an approximately 40% strength aqueous solution of tetra-n-butyl-ammonium hydroxide. The mixture was then extracted with 200 ml of THF. The extract was concentrated to dryness on a rotary evapora-lS tor and the residue was taken up on 300 ml of methyltrimethoxy-silane. Volatile constituents were then stripped off at 25~C/ 10 hPa.
The mixture was filtered. 192 g of a colorless, clear liquid having a fluoride content of 0.6 mole/l were obtained.
The advantage of this procedure lies in the fact that the hygroscopic tetrabutyl~mminium fluoride is practically dried with methyltri-methoxysilane. In the presence of the fluoride the residual moisture led to hydrolysis or condensation of the methyltrimethoxysilane.
Liquid oligomers of methyltrimethoxysilane and an insoluble precipi-tate of methylsilicic acid, which can be removed by simple filtration, 2s are formed.
0.2 ml of catalyst solution F1 described above under ~C) was added to a mixture of 100 g of a polydimethylsiloxane having OH end groups and a viscosity of 1000 mm2/s and 7.4 g of melhyll,imethoxy-silane (= 23 ppm of F, based on the weight of hydroxysiloxane) and the mixture was stirred for 20 minutes. The catalyst was deactivated by addition of 0.7 ml of a 10% strength solution of aluminum tri-sec-butylate in hexamethyldisiloxane. As a crosslinkin~ test showed (addition of aluminum tri-sec-butylate to small samples of the reac-214I9~5 tion mi~cture taken after certain intervals of time), all the SiOH groups had reacted in the desired sense after only 10 minutes (no further gelling with aluminum tri-sec-butylateJ. It was to be seen from the 29Si-NMR spectrum that all the OH end groups had been converted into H3CSi(OCH3)2- end groups.
Example 18 The procedure described in Example 17 was repeated, with the modification that 0.2 ml of catalyst solution F1 prepared in Example 17 under (C) (= 23 ppm of F, based on the weight of hydroxysiloxane) which had been stored at a temperature of 70~C in a polyethylene bottle for a period of 7 days was employed. As a cros~linkin~ test showed ~addition of aluminum tri-sec-butylate to small samples taken from the reaction mixture after certain intervals of time), all the SiOH groups had reacted in the desired sense after only 10 minutes ~no further gelling with aluminum tri-sec-butylate). It was to be seen from the 29Si-NMR spectrum that all the OH end groups had been converted into H3CSi(OCH)2- end groups.
Example 19 0.2 rnl of a 1.0 M solution of TBAF in THF was added to a mixture of 100 g of a polydimethy1~ilox~ne having OH end groups and a vis-cosity of 1000 mm2/s and 11.7 g of 2-cyanoethyltriethoxysilane (0.0002 mole of F, 38 ppm of F, based on the weight of hydroxysilox-ane). As a cros~linkin~ test showed (addition of aluminum tri-sec-butylate to small samples taken from the reaction mixture after cer-tain intervals of time), all the SiOH groups had reacted in the desired sense after only 10 minutes (no further gelling with alumi-num tri-sec-butylate). After this period of time, deactivation was carried out with 0.65 ml of a 10% sll~legth solution of aluminum tri-sec-butylate in hexamethyldisiloxane (0.00026 mole of Al). It was found in the 29Si-NMR spectrum of the mixture that all the SiOH
functions had been converted into Si-O-Si(OCH2CH3)2-(CH2)2-C~N and the ratio of end groups/dimethylsiloxy units had not changed com-pared with the starting value. The 29Si-NMR spectrum of a sample which had been subjected to storage under heat at 70~C in a dosed polyethylene bottle for 7 days showed no formation of monoethoxy end groups and/or branchings.
Example 20 0.1 ml of catalyst solution Fl described in Example 17 under C) was added to a mixture of 100 g of a polydimethylsiloxane having OH
end groups and a viscosity of 1000 mm2/s and 15.0 g of N-1~3-tri-ethoxysilyl)-propyl]-4,5-dihydroim~ 4le (commercially obtainable undcr the name"Dynasilan~ IMEO" from Hule AG, Marl) ~0.0006 mole of F, 11 ppm of F, based on the weight of hydroxyeil- Y~n~). Since no further gelling on samples taken occurred in the croselil.lnng test ac-cording to Example 19 with aluminum tri-sec-butylate after 20 min-utes, deactivation was carried out after this period of time with 0.16 ml of a 10% strength solution of aluminum tri-sec-butylate in hex-amethyldisiloxane (0.000065 mole of A1). It was found in the 29Si-NMR spectrum of the mixture that all the SiOH functions had been converted into Si-OSi(OCH2CH3)2-(CH2)3-N-dihydroimidazole and the ratio of end groups/dimethylsiloxy units had not changed compared with the starting value.
Example 21 0.2 ml of a 1.0 M solution of TBAF in THF was added to a mixture of 100 g of a polydimethylsiloxane having OH end groups and a vis-cosity of 1000 mm2/s and 0.9 g of N-l(3-triethoxysilyl)-propyll-4,5-dihydro-imidazole (commercially obtainable under the name ~Dyn~ n IMEO~ from Huls AG, Marl) and 7.6 g of vinyltriethoxy-silane (0.0002 mole of F, 38 ppm of F, based on the weight of hy-droxysiloxane). The end point of the reaction was determined by the crosslinkin~ test described in Example 19. Since no further gelling on samples taken occurred after 20 minutes, deactivation was carried out after this time with 0.65 ml of a 10% strength solution of alumi-num tri-sec-butylate in hexamethyldisiloxane (0.00026 mole of Al). It was found in the 29Si-NMR spectrum of the mixture that practically all the SiOH functions had been converted into ., ~, Si-OSi(OCH2CH3)2-CH=CH2 and the ratio of end groups/dimethyl-siloxy units had not changed compared with the starting value.
E~ample 22 0.2 ml of a 1.0 M solution of TBAF in THF was added to a mixture s of 100 g of a polydimethylsiloxane having OH end groups and a vis-cosity of 1000 mm2/s, 7.15 g of cyanoethyltriethoxysilane and 7.6 g of vi~ iethoxysilane (0.0002 mole of F, 38 ppm of F, based on the weight of hydroxysiloxane). The end point of the reaction was deter-mined by the crosslinkin~ test described in Example 19. Since no further gelling on samples taken occurred after 10 minutes, deactiva-tion was carried out after this time with 0.65 ml of a 10% strength solution of aluminum tri-sec-butylate in hexamethyl~ ilo~ne (0.00026 mole of Al). It was found in the 29Si-NMR spectrum of the mixture that 93.3% of all the SiOH functions had been converted into Si-OSi(OCH2CH3)2-CH2CH2-CN and 7.7% of all the SiOH functions had been COn~ led into Si-OSi(OCH2CH3)2-CH=CH2, and the ratio of end groups/dimethylsilo~y units had not changed compared with the starting value. The 29Si-NMR spectrum of a sample which had been subjected to storage under heat at 70~C in a closed polyethylene bottle for 7 days showed no formation of monoethoxy end groups and/or branchings.
Docket: WA 9343-S
Paper No. 1 PROCE~ FOR TH~: PREPARA'rIOII OF ORGAl~OPOLY~ILOXAI~I~
CONTAIl!II~IG ORGAIIYLOXY GROUP~3 Field of Invention The invention relates to a process for the preparation of organopoly-siloxanes containing organyloxy groups by reaction of hydroxysiloxanes with 0 organyloxysilanes, and the use thereof in compositions which can be cross-linked at room temperatures.
Back~round of Invention Processes for the preparation of organopolysiloxanes contz~inin~
organyloxy groups are already known. For ex~ple, U.S. 5,196,497 (Bayer AG, issued on March 23, 1993) and the corresponding EP 468 239 A2 describe the reaction of a,~-dihydroxypoly(diorganosiloxanes) with alkoxy-silanes in the presence of alkali metal hydroxides, which leads, by elimin5~-tion of alcohol, to the desired polysiloxanes blocked by end groups. The strong bases have a high equilibrating activity and, if the reaction time is too long or the temperatures relatively high often lead to an undesirably high content of monoalkoxy end groups which are not capable of crosslink-ing. Deactivation of the catalyst with strong acids, such as, chlorosilanes or phosphoric acid, must therefore be careried out at precisely the right time.
Since the reaction may occur literally within a minute, the time between addition of the catalyst and deactivation of the catalyst of ~veral minutes, customary during factory production, can result in a product which does not meet the specification. Furthermore, the amount of deactivating reagent should be precisely matched stoichiometrically to the amount of catalyst employed, in order to quarantee the storage stability of the end product. In practice, an excess of deactivating reagent will therefore often have to be employed. Since these are strong acids having an equilibrating activity, this excess must be removed from the product again.
U.S. 5,055,502 (Phone-Poulenc Chemie; issued on October 8, 1991) describes a process in which zinc chelate complexes effect the blocking of the ends of OH polymers with alkoxysilanes at relatively high temperatures.
DE 3428840 Al (General Electric Co.; published on February 21, 1985) and the col~esponding GB 2144758 A disclose aluminum chelate complexes which are employed as catalysts for alkoxy blocking of the ends of organo-polysiloxanes containing OH groups. In U.S. 5,166,296 (General Electric Co.; issued on November 24, 1992) and the corresponding EP 520 718 A2, the preparation of polysiloxanes blocked by alkoxy end groups from aL~coxy-nes and polysilox~qnes having terminal OH groups is car~ied out in the presence of catalytic amounts of ammonium salts of carboxylic acids.
Sllmm~t~r of Invention 0 The present invention relates to a process for the preparation oforganopolysiloxanes which contain at least one unit of the formula (RlO)3 mRmSiOl/2 (I) in which R is identical or different and is a hydrogen atom or monovalent, optionally substituted hydrocarbon radical, Rl is identical or different and is a monovalent, optionally substituted hydrocarbon radical having 1 to 8 carbon atoms and m is 0, 1 or 2, which comprises, in a 1st step, reacting org~nosilicon compounds (1) which 20 contain at least one Si-bonded hydroxyl group with at least one silane (2) of the formula (RlO)4 mSiRm (II) and/or partial hydrolysates thereof, in which R, R' and m have the above mentioned meaning, in the presence of a fluoride salt (3), and, optionally, in 25 a 2nd step, when the reaction has ended, adding component (4) which can bond fluoride ions.
The term organopolysiloxanes in the context of the present invention is also intended to include oligomeric siloxanes.
The radical R is preferably monovalent, optionally substituted hydro-30 carbon radicals having 1 to 13 carbon atoms, where the methyl, vinyl and3-(N-cyclohexylamino)propyl radical are more preferred.
Examples of the radical R are allcyl 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 r~ic~l~, such as the n-hexyl radical, heptyl radicals, such as the n-heptyl radical, octyl radicals, such as the n-octyl radical, and iso-octyl radicals, such as the 2,2,4-tri-methylpentyl radical, nonyl radicals, such as the n-nonyl radical, decyl radicals, such as the n-decyl radical, and dodecyl radicals, such as the n-dodecyl radical; aLt~enyl radicals, such as the vinyl and the allyl radical;
cycloaLtcyl radicals, such as cyclopentyl, cyclohexyl and cycloheptyl radicals and methylcyclohexyl radicals; aryl radicals, such as the phenyl and the naphthyl radical; aL~aryl radicals, such as o-, m- and p-tolyl radicals, xylyl radicals and ethylphenyl radicals; and araL~cyl radicals, such as the benzyl radical and the a- and ~-phenylethyl radical.
Examples of substituted hydrocarbon radicals are haloaLtcyl radicals, such as the 3,3,3-trifluoro-n-propyl radical, 2,2,2,2',2',2'-hexafluoroiso-propyl radical and the heptafluoroisopropyl radical; haloaryl r~-lic~l~, such as the o-, m- and p-chlorophenyl radical; the 3-thio-1-propyl radical;
acyloxyaL~cyl radicals, such as the acetoxyethyl radical and (meth)acryloylo~y~ropyl radical; and A
CH2-CH-CH2-0-CH2-, HSCH2-, H2NCH2-, 4,5-dihydroimi~1~701-l-yl-CH2-, imi~l~701-l-yl-CH2-, pyrrolidinyl-CH2-, piperidyl-CH2-, N-morpholinyl-CH2-, pipera_inyl-CH2-, cyclohexyl-NH-CH2-,H2N-CH2CH2-NH-CH2-, H2C=C(CH3)C00-CH2-, 2-cyanoethyl-, 3-cyanopropyl-, CH2-CH-CH2-0-(CH2)3-, HS(CH2)3-, H2N(CH2)3-, 4,5-dihydroimidazol-1-yl-(CH2~3-, imida_ol-l-ly-(CH2~3-, pyrrolidinyl-(CH2~3-. piperidyl-(CH2~3, N-morpholinyl-(CH2~3-, piperazinyl-(CH2~3-, cyclohexyl-NH-(CH2~3-, H2N-CH2-CH2-NH-(CH2)3- and H2C=C(CH3)C00-(CH2)3- radical.
Examples of the radical Rl are the examples of optionally substituted hydrocarbon radicals having 1 to 8 carbon atoms mentioned for R.
The radical Rl is preferably a methyl, ethyl, n-propyl, isopr< ~yl, pro-pen-2-yl, n-butyl, sec-butyl or iso-butyl radical, methyl and ethyl radicals being more preferred.
21419B~
The organosilicon compounds (1) cont~ining at least one Si-bonded hydroxyl group which are employed in the process according to the inven-tion are preferably those chosen from the group conci~ting of organopolysi-loxanes having at least one Si-bonded hydro~yl group, and organosilanes having a hydroxyl group.
The organosilicon compound (1) cont~ining at least one Si-bonded hydroxyl group which is employed in the process according to the invention can be any of the hydroxysiloxanes and monohydroxysilanes known to date.
The hydroxysiloxanes employed according to the invention can of course contain other units containing Si-bonded hydroxyl groups, such as (HO)2 ~R3~SiO2/2 and HOSiO3/2 units, in addition to units of the formula (HO)3 tR3,SiOl/2, in which R3 has one of the me~nin~ given for R1 t is 0, 1 or 2 and sis0 or 1.
Ex~mples of the organosilicon compound (1) employed according to the invention are a,Q)-dihydroxydiorganopolysiloxanes, such as HOMe2Si(OSiMe2)l to looooOH and HOMe2Si(OSiMe2)0 to lOOOO(OSiMeVi)o to looooOH, where this siloxane cont~ s at least two silicon atoms, a-monohydroxydiorganopolysiloxanes and monohy-droxysilanes, such as Me3Si(OSiMe2)0 ~ looooOH, HMe2Si(OSiMe2)~ ooooOH, (H2C=CH)Me2Si(OSiMe2)0 to looooOH and (H2C=CHCH2)Me2Si(OSiMe2)0 to looooOH, where Me is the methyl radical and Vi is the vinyl radical, and branched hydroxy-functional organopolysilox-anes and hydroxy-functional organopolysiloxane resins, such as described in EP 540 039 Al (Dow Corning Japan Ltd.), column 5, lines 37 to 40 and column 6, line 25, the olg~lyl r~-lic~ preferably being methyl r~tlic~
Fur~er examples are organosilicon compounds of the above mentioned type which contain hydroxyl groups and, in addition to methyl groups, also con-tain phenyl groups, vinyl groups, l-thio-3-propyl groups or 3,3,3-trifluoro-propyl groups.
The hydroxysiloxanes (1) employed according to the invention have a viscosity at 25~C of preferably 1 to 106 mm2/s, more preferably 10 to 5 x 105 mm2/s.
214198~
The organosilicon compounds (1) employed according to the invention are more preferably a,~-dihydroxyldiorganopolysiloxanes.
The organosilicon compounds which contain hydroxyl groups and are employed according to the invention can be one type of such organosilicon 5 compounds or a mixture of at least two different types of organosilicon com-pounds.
The organosilicon compounds which contain hydroxyl groups and are employed according to the invention are commercially available products or can be prepared by processes customary in silicone chemistry.
Examples of the silanes (2) employed according to the invention are Si(OCH3)4, Si(OCH2CH3)4, H3CSi(OCH3)3, CH3Si(OCH2CH3)3, H2C=CH-Si(OCH3)3, H2C=CH-Si(OCH2CH3)3, C6Hs-Si(OCH3)3, (H3C)2Si(OCH3)2, HSi(OCH2CH3)3, F3CCH2CH2Si(OCH3)3, H2C=CH(CH2)4-Si(OCH3)3, N_C-CH2CH2-Si(OR')3, N-C-CH2CH2CH2-Si(OR')3, and XCH2CH2CH2Si(ORI)3 where X is ~O
CH2-CH-CH2-O-, HS-, H2N-, 4,5-dihydroimi~1~7ol-l-yl, imidazol-l-yl, pyrrolidinyl-, piperidyl-, N-morpholinyl-, piperazinyl-, cyclo-hexyl-NH-, H2N-CH2CH2-NH-, or H2C=C(CH3)COO- radical and Rl has the above mentioned me~ning. Some of these silanes also react with OH-func-tional organosilicon compounds even in the absence of catalysts. In such cases, reaction times can be shortened and/or reaction temperatures low-ered by the process according to the invention, which can bring advantages during further proces~ing of the products.
The silanes (2) employed according to the invention are preferably Si(OCH3)4, Si(OCH2CH3)4, H3CSi(OCH3)3, CH3Si(OCH2CH3)3, H2C=CH-Si(OCH3)3, H2C=CH-Si(OCH2CH3)3, N=C-CH2CH2Si(OCH2CH3)3, 4,5-dihydroimi-1~7.ol- l-yl-CH2CH2CH2SitOCH2CH3)3, (~2-CH-CH2-O-CH2CH2CH2Si(OCH3)3, H2C=C(CH3)COOCH2CH2CH2-Si(OCH3)3, cyclohexyl-NH-CH2CH2CH2-Si(OCH3)3, H2N-CH2CH2-NH-CH2CH2CH2-Si(OCH3)3, HS-CH2CH2CH2-Si(OCH3)3 and N-morpholinyl-CH2CH2CH2-Si(OCH3)3, where H3CSi(OCH3)3, CH3Si(OCH2CH3)3, H2C=CH-Si(OCH3)3, H2C=CH-Si(OCH2CH3)3, N-C-CH2CH2Si(OCH2CH3)3, 4,5-dihydroimiti~7~0l-l-yl-CH2CH2CH2Si(OCH2CH3)3 and cyclohexyl-NH-CH2CH2CH2-Si(OCH3)3 are more preferred.
The silanes (2) employed according to the invention can be a single type or a mixture of at least two different types of such silanes or partial hydrolysates thereof.
If partial hydrolysates of the silanes (2) are employed in the process 0 according to the invention, these are preferably those which are liquid at room te~ ature.
The silanes (2) employed according to the invention or partial hydro-lysates thereof are commercially available products or can be prepared by processes customary in silicone chemistry.
The silane (2) and/or partial hydrolysate thereof is advantageously employed in the process according to the invention in a stoichiometric excess with respect to Si-bonded hydroxyl groups. The silane (2) and/or partial hydrolysate thereof is preferably employed in amounts of 1.0l to 20 mole per mole of Si-bonded hydroxyl groups of the compound (1), more preferably 1.01 to 10 mole per mole of Si-bonded hydroxyl groups of the compound (1). Higher excesses can be favorable if the preparation of com-positions based on the ol~.yloxysiloxanes prepared according to the in-vention which can be crosslinked by moisture at room temperature and in which the excess organyloxysilane serves as the cros~1inking agent is desired. Under certain circumstances, a further metering operation thus becomes superfluous, which can have an advantageous effect in particular during continuous preparation of RTV- 1 compositions.
The fluoride salt (3) employed in the process according to the inven-tion is preferably one chosen from the group consisting of ammonium fluo-rides of the formula [R24N]F (III) in which R2 can be identical or different and has one of the me~nings {pven f~r R, adducts thereof with carbonyl compounds, such as ~-ketocarboxylic 214198~
acid esters of 1,3-diketones, (alkali) metal fluoAdes, such as potassium fluoride, cesium fluoride, zinc fluoride, dibutyltin fluoride and copper fluo-ride, and organic or inorganic ammonium hydrogen fluorides, phosphonium fluorides, phosphonium hydrogen fluorides, tetratluoroborates, hexafluoro-silicates and fluorophosphates.
The radical R2 is preferably the methyl, ethyl, n-butyl, n-propyl, iso-propyl or the benzyl radical, where the methyl, n-butyl and benzyl radical are more preferred.
The fluoride salt (3) employed in the process according to the inven-tion is more preferably ammonium fluoride of the formula (III).
Examples of the fluoride salt (3) are l(H3C(CH2)3)4N]F (called TBAF
below), l(H3C)4NlF, lC6H5CH2-N(CH3)3]F and [H3CNH3]F and adducts thereof with carbonyl compounds, where acetylacetone, methyl acetoacetate, 2-ethylhexyl acetoacetate and isopropyl acetoacetate are preferred and acetylacetone and ethyl acetoacetate are more preferred as the carbonyl compound.
Fluoride salts are commercially available products or can be prepared by processes customary in organic chemistry. Reference may be made for example to, Clark, J.H., Miller, J.M. in J. Chem. Soc., Perkin Trans.I, 1977, 1743- 1745.
The fluoride salts (3) employed according to the invention can be a single type or a mixture of at least two different types of such fluoride salts.The fluoride salt (3) can be employed in the process according to the invention as a mixture with organic solvents and/or organosilicon com-pounds or in a form fixed to support materials, such as silicic acid, ion exch~nger resin, titanium dioxide or aluminum oxide. Processes for the preparation of fluoride salt bonded to a support material are described, for example, in Gambacorta, ~, Turchetta S., Botta, M., Synth. Commun., 1989, 19 (13-14), 2441-2448; Li, C., Lu, Y., Huang, W., He, B., Synth.
Commun., 1991, 21(12-13), 1315-1320.
All the known organic solvents which have no interfering effect on the reaction procedure can be employed as solvents; the solvents are preferably 21~198~
_ organic solvents, which can easily be removed from the end product by ~olation. Examples of such solvents are diethyl ether, dibutyl ether, tetrahydrofuran, dioxane, hexane, toluene, xylenes, chlorobenzene, 1,3-pentanedione, acetone, methyl t-butyl ketone, methyl ethyl ketone, 5 1,2-dimethoxyethane, acetonitrile, ethyl acetate, methyl acetate, butyl ace-tate, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, methanol, ethanol, n-propanol, 2-propanol, n-butanol, 2-butanol and isobutanol and mixtures of these solvents.
The fluoride salt (3) can also be employed in the process according to lO the invention as a mixture with organosilicon compounds, such as silanes or oligomeric or polymeric siloxanes.
In the ple~alation of mixtures which can be crosslinked by moisture at room temperature after the preparation according to the invention of the organyloxysiloxanes in particular it is advantageous to dissolve the fluoride l5 salt (3) in the organyloxysilanes to be reacted, if api)ro~,iate with the addi-tion of the corresponding free compound RlOH, where Rl has the above mentioned meaning, or in another liquid constituent, such as OH-cont~ining polysiloxane or a poly(diorganosiloxane) blocked by end groups, which is often employed as plasticizer, such as (H3C)3SiO-[Si(CH3)20]70-Si(CH3)3, an 20 oligomeric siloxane, such as (H3C)3SiOSi(CH3)3, or a cyclosilox~ne, such as Si(CH3)20]4.
Both the adducts with carbonyl compounds and the ammonium fluorides adsorbed onto support materials often have the advantage that they are less hygroscopic and therefore have a better storage stability than 25 the pure ammonium fluorides.
The fluoride salt (3) is employed in the process according to the invention in amounts of preferably 0.1 to 1000 ppm (parts by weight per million parts by weight), more preferably 1 to 100 ppm, in each case calcu-lated as elemental fluorine and based on the total weight of organosilicon 30 compound (1). The amount of fluoride salt (3) to be employed depends in particular on the reactivity of the individual reaction partners and on the presence of constituents which accelerate or retard the reaction, such as compounds having acid or basic radicals or fluoride-bonding constituents.
The conditions under which the process according to the invention can be catried out primarily depend on the reactivity of the olg~-yloxysilane (2) employed and on the nature and concentration of the fluoride salt ~3).
The process according to the invention is carried out at temperatures of preferably 20~ to 100~C under a pressure of preferably 900 to 1100 hPa.
However, it can also be carried out at higher or lower temperatures and un-der higher or lower pressures.
In most cases, the process according to the invention can be carried out at room temperature. However, it may be advantageous, for example, if a lower viscosity of the reaction mixture is required for technical reasons, to carry out the reaction at elevated temperature; in this case acceleration of the reaction is in general to be expected under otherwise the same condi-tions.
The end of the reaction according to the invention can be detected by lS measuring the SiOH content in the reaction mixture by means of IR spec-troscopy, 29Si-NMR or lH-NMR spectroscopy or by a cros~linking test to detect residual SiOH functions in polysiloxanes, such as by the cros~linking test according to EP 468 239 A2 cited above, or by addition of aluminum tri-sec-butylate; an immediate increase in viscosity, under certain circum-stances up to gelling, indicates residual SiOH groups and therefore incom-plete co.lversion.
When the reaction according to the invention has ended, the fluoride salt (3) is preferably deactivated by addition of component (4), which can bond fluoride ions, the aim being to suppress further unwanted reactions and to ensure that the organopolysiloxanes which contain organyloxy groups and are prepared according to the invention do not change during storage.
Examples of component (4) are aluminum compounds and com-plexes, such as aluminum alcoholates, pyrogenically produced or precipi-tated silicic acid, calcium-cont~ining fillers, which are suitable for deactiva-tion of component (3) because of the high tendency towards formation of calcium fluoride, such as calcium carbonate, calcium silicate, calcium phosphate and chalks whose surface has been treated with carboxylic acids 214198~
such as 2-ethylhexanoic acid (so-called coated chaL~s), and mixtures thereof.
Aluminum compounds or complexes are preferably employed as component (4) in the process according to the invention.
Examples of compounds and complexes of aluminum are aluminum carboxylates, aluminum thiolates, aluminum sulfonates, aluminum phos-phonates, aluminum amides, aluminum sil(ox)anolates, aluminum halides, aluminum alcohol~tes and aluminum alcoholates in which one or more a~coxy radicals can be replaced by ~-dicarbonyl chelating ligands, for ex-0 ample Al[OCH2CH3l3, Al[OCH(CH3)(C2Hs)]3, Al[OCH(CH3)2]3, AllH3C-C(O)CHC~O)-CH3]3, AllOCH(CH3)2]2lH3CC(O)CHCOOCH2CH3], alumi-num complexes according to formula (4) of DE 34 28 840 Al cited above, such as aluminum di(methoxy)ethylacetoacetonate, aluminum methoxy-di(ethylacetoacetonate), aluminum di(isopropoxy)acetylacetonate, aluminum isopropoxy-di(acetylacetonate), aluminum isopropoxy-di(ethylacetoace-tonate), aluminum bis(trimethylsiloxy)ethylacetoacetonate, aluminum bis(dimethoxymethylsiloxy)ethylacetoacetonate, aluminum bis(dimethoxy-methylsiloxy)acetylacetonate, aluminum tri(ethylacetoacetonate), aluminum bis(dimethylamino)ethylacetoacetonate, aluminum 1,3-propanedioxyethyl-acetoacetonate and aluminum di(isopropoxy)(methylsalicylate), and reaction products of aluminum alcoholates and organyloxysilanes of the formula III), such as di-sec-butoxyaluminoxytriethoxysilane and the reaction product of aluminum di(isopropoxy)-ethylacetoacetonate and tetraethoxysilane.
An aluminum alcoholate is more preferably employed as component (4) in the process according to the invention.
Component (4) employed according to the invention can be a single type or a mixture of at least two different types of such components (4).
The aluminum compounds and complexes employed as component (4) are commercially available products or can be prepared by processes customary in chemistry.
The aluminum compound or complex (4) can be employed in the process according to the invention as a mixture with organic solvents and/or organosilicon compounds, which is preferred.
Solvents and organosilicon compounds which can be employed are the same as those which were described above in connection with the fluo-ride salt (3), the aluminum compound or complex ~4) preferably being employed as a mixture with tetrahydrofuran and/or polydiorganosiloxanes, such as (H3C)3SiO[Si(CH3~2l70-Si(CH3)3, (H3C)3SiOSi(CH3)3 and ¦Si(CH3)2O]4.
At least a stoichiometric equivalent of aluminum in the form of the aluminum compound or complex ~4) with respect to the fluoride is prefera-bly added in the deactivation step acco~ding to the invention. The alumi-num compound or complex (4) is more preferably employed in amounts of 1.05 to 3 mole of aluminum per mole of fluoride of component (3).
The process according to the invention can be car~ied out continu-ously or discontinuously.
The elimin~tion of the organopolysiloxanes according to the invention cont~inin~ organyloxy groups after the reaction according to the invention or after the deactivation step according to the invention can be carried out by any desired and known methods. For example, after the deactivation step according to the invention, the excess organyloxysilane (2), the compound RlOH liberated as a cleavage product, where R' has the above mentioned me~ning, and other possible cleavage products and solvents can be removed by thorough heating and/or by reducing the pressure.
The organopolysiloxanes which contain organyloxy groups and are prepared according to the invention can be employed for all purposes for which organopolysiloxanes having organyloxy groups have also been employed such as, for co~hngs to improve the water-repellent properties of substrate surfaces, as an adhesion promoter additive, as a primer, for adhesives, for tex~le coatings, for plasticizers (which can be crosslinked in ifthe siloxane is blocked by organyloxy at only one end) and as a base poly-mer in organopolysiloxane compositions which can be cros~linked by mois-ture, in particular RTV-l compositions.
Organopolysiloxane compositions which can be cross1inked by mois-ture and processes for their preparation are generally known. They essen-tially comprise base polymer, vll1c~ni7~hon catalysts, cros~linking agents . 2141985 and, optionally, plasticizers (in general silicone oils which are blocked with non-reactive end groups), fillers, adhesion promoters and stabilizers.
For certain intended uses of the organopolyci10~c~nes which contain organyloxy groups and are prepared according to the invention, in particu-5 lar for their use in compositions which crosslink by means of moisture, thereaction composition obt~ined according to the invention can be employed without ~limin~ti~n of the organopolysiloxane which contains organyl groups. In this case, an excess of the silane (2) employed in the process according to the invention can serve as the cros~1inking agent. If pyrogenic 0 silicic acid is employed as a constituent, the amount of aluminum com-pound can be greatly reduced proportionally, or its use can be dispensed with entirely, because of the high adsorptive bonding of fluoride ions onto the silicic acid surface.
It is essential, for the stability of the compositions which can be 5 crosc1ink~d by means of moisture, only that complete reaction of the hydroxyl groups of the organosilicon compound (l) with the organyloxy-silane (2) has taken place before addition of the pyrogenic silicic acid. This applies to calcium-cont~ining fillers or additives, which are suitable for the deactivation because of the high tendency toward the formation of calcium 20 fluoride.
If use of the polysiloxanes prepared by the process according to the invention in organopolysiloxane compositions which cure by means of moisture is intended, the process according to the invention can also be carried out as a one-pot process or continuously in the mixin~ unit envis-25 aged for preparation of the compositions which cros~link by means ofmoisture. In the latter case, the fluoride salts (3) and the deactivating rea-gents (4) can be combined with the reaction medium in static mixer systems with the aid of metering pumps.
The process according to the invention has the advantage that 30 organopolysiloxanes cont~ining organyloxy groups can be prepared in a simple manner and selectively with a high rate of reaction.
The fluoride component (3) employed according to the invention has the advantage that it has a highly accelerating action on the reaction accord-ing to the invention and has only a moderate equilibrating activity.
If component (4) is added, there is a further advantage in that by the S deactivation step with aluminum alcoholates carried out according to theinvention, storage-stable end products are accessible without an after-treatment step, even if the deactivating aluminum compound is employed in a small stoichiometric excess.
In the examples described below, all parts and percentage data relate 0 to the weight, unless stated otherwise. Furthermore, all the viscosity data relate to a temperature of 25~C. Unless stated otherwise, the following examples were carried out under a pressure of the surrounding atmosphere at about 1000 hPa and at room te~l~elature at about 20~C, or a tempera-ture which is established when the reactants are brought together at room temperature without additional heating or cooling.
TBAF represents tetra-n-butylammonium fluoride THF represents tetrahydrofuran E~ample 1 A Preparation of the aluminum component A mixture of 27.6 g of water and 230 g of THF is added to a solu-tion of 210 g of aluminum di(isopropoxy)-acetoacetic ester chelate (=Al[O-CH(CH3)2]2[H3C-C(O)CHC(O)OC2Hsl) and 319 g of tetraethoxy-silane in 766 g of THF at room temperature in the course of 30 min-utes. The mixture was then heated under reflux for one hour.
Thereafter, all the volatile constituents were stripped off at room tem-perature under 3 hPa. After filtration, 344 g of a clear oily liquid, the aluminum content of which was 3.9% by weight, were obtained.
A mixture of 2000 g of a polydimethylsiloxane having OH end groups and a viscosity of 1000 mm2ts with 145 g of methyl-trimethoxysilane was prepared in a planetary mixer. 4.3 ml of 1.1 M
solution of TBAF in THF were stirred into this mixture (=0.0047 mole of F; 45 ppm of F, based on the weight of hydroxysiloxane). After 25 minutes, 7.74 g of a solution of 3.87 g of the aluminum component '_ described under A) in 3.87 g of mel~lylL,i~ethoxysilane were added (=0.0056 mole of A1). After the components had been mixed thor-oughly for 5 minutes, a 29Si-NMR spectrum and a gel permeation chromatogram of the reaction mixture were recorded. It was found that all the OH end groups had been replaced by H3CSi(OCH3)2-O-end groups. Gel permeation chromatography showed a molecular size distribution (excluding the excess methyltrimethoxysilane) which corresponded to that of the OH group-cont~ining polymer employed.
E~ample 2 1.3 ml of 1.1 M solution of TBAF in THF were added to a mixture of 150 g of polydimethylsiloxane having OH end groups and a viscosity of 70 mm2/s and 48.96 g of methyltrimethoxysilane (0.0014 mole of F, 181 ppm of F, based on the weight of hydroxysiloxane). After 20 minutes, the catalyst was deactivated by addition of 2.6 ml of a 50%
strength solution of the aluminum component described in Example 1 under A) in methhyltrimethoxysilane ~0.0019 mole of Al). The volatile constituents were then distilled off up to 80~C/ 12 hPa. 155 g of a clear colorless oil remained as the residue, the average formula of which was obtained from the 29Si-NMR spectrum:
MeSi(OMe)2-(SiMe20)44-Si(OMe)2Me.
Comparison Example 1 0.55 ml of a 10% strength solution of aluminum tri-secbutylate in THF was added to a mixture of 100 g of a polydimethylsiloxane hav-ing OH end groups and a viscosity of 1000 mm2/s and 14.8 g of methyltrimethoxysilane, after which the formation of gelatinous regions occurred suddenly, which is to be interpreted as an indication of incomplete saturation of the Si-OH groups of the polydimethylsi-loxane having OH end groups. In addition to me~ imethoxysilane and the dimethylsiloxy units of the OH-polymer, only HO-Si(CH3)2-O-and no H3CSi(OCH3)2-O- end groups were detectable in the 29Si-NMR
spectrum.
~:xample 3 A mixture of 2000 g of a polydimethy~ ox~ne having OH end groups and a viscosity of 1000 mm2/s with 145 g of mell~yllli-methoxysilane was prepared in a planetary mixer. 4.3 ml of a 1.1 M
s solution of TBAF in THF were stirred into this mixture (= 0.0047 mole of F; 45 ppm of F, based on the weight of hydroxysiloxane). After storage at 25~C for two days, products of polymer degradation reac-tions (equilibration) were detected from the 29Si-NMR spectrum: the content of monomethoxy end groups, which are not capable of 0 crosslinking, was 20 mole %, based on all the end groups (80 mole %
of H3CSi(OCH3)2 end groups); the chain lengthening content of Si~CH3)0CH3-groups incorporated, was the same size.
Dimethyldimethoxysilane was also detectable.
E~ample ~
5 B Preparation of catalyst solution F
150 ml of 4% strength hydrofluoric acid were added to 195 ml of a 40% strength aqueous solution of tetra-n-butyl-ammonium hydroxide. The pH of the solution was 7. After addition of 60 g of 2,5-pentanedione, all the volatile constituents were distilled off on a rotary evaporator at 40~C/ 1 hPa. 5.5 g of the solid residue were dis-solved in 30 ml of methyltrimethoxysilane. A clear red-brown solu-tion having a nuoride content of 0.014 g/ml was obtained.
0.1 ml of the catalyst solution F described above under (B) was added to a mixture of 100 g of polydimethylsiloxane having OH end groups and a viscosity of 1000 mm2/s and 7.4 g of methyltrimethoxy-silane (=0.000074 mole of F; 14 ppm of F, based on the weight of hydroxysiloxane~ and the mixture was stirred for 20 minutes. The catalyst was deactivated by addition of 0.55 ml of a 10% strength solution of aluminum tri-sec-butylate in THF (0.000223 mole of Al).
As a cros~linkin~ test showed (addition of aluminum tri-sec-butylate to small samples taken from the reaction mixture after certain inter-vals of time), all the SiOH groups had reacted in the desired sense after only 15 minutes (no further gelling with aluminum tri-sec-butylate). It was to be seen from the 29Si-NMR spectrum that aU the OH end groups had been converted into H3CSi(OCH3)2- end groups.
E~ample 5 The procedure described in Example 4 was repeated with the modi-fication that, instead of 0.1 ml, 0.2 ml of catalyst solution F
l= 0.000147 mole of F; 28 ppm of F, based on the weight of hydroxy-siloxane) was added. From the crosslinking test for residual SiOH, it was found that the reaction had already ended after 10 minutes.
Nevertheless, deactivation with the aluminum component was carried 0 out only after 20 minutes. The 29Si-NMR spectrum was identical to that from Example 4.
Example 6 The procedure described in Example 4 was repeated, with the modification that inete~l of 0.1 ml, 0.3 ml of catalyst solution F
(= 0.00022 mole of F; 42 ppm of F, based on the weight of hydroxysi-loxane) was added. It was found from the croselinking test for resid-ual SiOH that the reaction had already ended after 5 minutes. Never-theless, deactivation with the aluminum component was carried out only after 20 minutes. The 29Si-NMR spectrum was identical to that from Example 4.
The 29Si-NMR spectrum of a sample which had been subjected to storage under heat in a closed polyethylene bottle in a drying cabinet at 80~C for 7 days, showed no change compared with the starting spectrum.
E~ample 7 The procedure described in Example 5 was repeated, with the modification that instead of 0.2 ml of catalyst solution F as described in Example 4 under B), 0.2 ml of a 1.1 M TBAF solution in THF
(0.00022 mole of F) was added. After 20 minutes, deactivation was carried out with 1.1 ml of a 10% strength solution of aluminum tri-sec-butylate in THF ~0.00045 mole of Al). The 29Si-NMR spectrum was identical to that of Example 5.
The 29Si-NMR spectrum of a sample which had been subjected to storage under heat in a closed polyethylene bottle in a drying cabinet at 80~C for 7 days showed no change compared with the initial spec-trum.
E~ample 8 The procedure described in Example 7 was repeated, with the modification that after 20 minutes the deactivation was carried out with 2.2 ml in~te:~tl of 1.1 ml of a 10% strength solution of aluminum tri-sec-butylate (0.00089 mole of Al). The 29Si-NMR spectrum was identical to that of Example 5.
The29Si-NMR spectrum of a sample which had been subjected to storage under heat in a closed PE bottle in a drying cabinet at 80~C
for 7 days showed no change compared with the starting spectrum.
Compllrison E~mple 2 A mixture of 0.2 ml of a 1.1 M solution of TBAF in THF (0.00022 mole of F) and 0.6 ml of a 10% strength solution of aluminum tri-sec-butylate in THF (0.00024 mole of Al) was added to a mixture of 100 g of a polydimethylsiloxane having OH end groups and a viscosity of 1000 mm2/s and 10 g of methyltrimethoxysilane. It was found from the 29Si-NMR spectrum of the reaction mixture that no reaction had taken place.
E~ample 9 0.2 ml of a 1.0 M solution of TBAF in THF was added to a mixture of 100 g of a polydimethylsiloxane having OH end groups and a vis-cosity of 1000 mm2/s and 12.7 g of 3-glycido~y~ropyltrimethoxy-silane (H2C(O)CHCH20(CH2)3-Si(OCH3)3 (0.0002 mole of F, 38 ppm of F, based on the weight of hydroxysiloxane). After 45 minutes, deacti-vation was carried out with 0.55 ml of a 10% strength solution of aluminum tri-sec-butylate in THF (0.00022 mole of Al). It was found in the 29Si-NMR spectrum of the mixture that all the SiOH functions had been converted into Si-OSi(OCH3)2-(CH2)3-OCH2-CH(O)CH2. The excess silane employed could be removed by thorough heating at 1 10~C/0. 1 hPa on a thin film evaporator.
Example 10 0.2 ml of a 1.0 M solution of TBAF in THF was added to a mixture of 100 g of a polydimethyl~ilox~ne having OH end groups and a vis-cosity of 1000 mm2/s and 13.4 g of 3-methacryloylo~y~royyl~i-methoxysilane (H2C=C(CH3)COO(CH2)3-Si(OCH3)3) (0.0002 mole of F, 38 ppm of F, based on the weight of hydroxysiloxane). After 25 min-utes, deactivation was carried out with 0.55 ml of a 10% strength solution of aluminum tri-sec-butylate in THF (0.00022 mole of Al).
It was found in the 29Si-NMR spectrum of the mixture that all the 0 SiOH functions had been converted into Si-OSi(OCH3)2-(CH2)3-OOC(CH3)C=CH2. The excess silane employed could be removed by thorough heating at 110~C/0.1 hPa on a thin film evaporator.
Example 11 0.2 ml of 1.1 M solution of TBAF in THF was added to a mixture of 100 g of a polydimethylsiloxane having OH end groups and a viscos-ity of 1000 mm2/s and 14.2 g of 3-(N-cyclohexylamine)plo~yl~
methoxysilane (cyclohexyl-HN-(CH2)3-Si(OCH3)3) (0.00022 mole of F>
42 ppm of F, based on the weight of hydroxysiloxane). After 15 minutes> deactivation was carried out with 0.22 g of the aluminum component described in Example 1 under A) (0.0003 mole of A1). It was found in the 29Si-NMR spectrum of the mixture that all the SiOH
functions had been converted into Si-OSi(OCH3)2-(CH2)3-NH~cyclo-hexyl).
Example 12 0.2 ml of a 1.0 M solution of TBAF in THF was added to a mixture of 100 g of a polydimethylsiloxane having OH end groups and a vis-cosity of 1000 mm2/s and 8.9 g of triethoxysilane (0.0002 mole of F>
38 ppm of F> based on the weight of hydroxy~ilo~c~ne). After 15 min-utes> deactivation was carried out with 0.55 ml of a 10% strength solution of aluminum tri-sec-butylate in THF (0.00022 mole of Al). It was found in the 29Si-NMR spectrum of the mixture that all the SiOH
functions had been converted into Si-OSiH(OCH2CH3)2.
_ 214198S
Example 13 0.2 ml of a 1.0 M solution of TBAF in THF was added to a mixture of 100 g of a polydimethylsiloxane having OH end groups and a vis-cosity of 1000 mm2/s and 6.5 g of dimethyldimethoxysilane (= 0.0002 mole of F, 38 ppm of F, based on the weight of hydroxysi-loxane). After 15 minutes, deactivation was carried out with 0.55 ml of a 10% strength solution of aluminum tri-sec-butylate in THF
(0.00022 mole of A1). It was found in the 29Si-NMR spectrum of the mixture that all the SiOH functions had been converted into Si-OSi(CH3)20CH3.
Example 14 1 ml of a 1.0 M solution of TBAF in THF was added to a mixture of 50 g of a branched polydimethylsiloxane having OH end groups and the average composition [HOSi(CH3)201/2l4-[Si(CH3)20l;,2¦SiO2ll 2 (prepared by gentle hydrolysis of a reaction product, prepared in the presence of PNC12, SiClq and a polydimethylsiloxane having OH end groups and a viscosity of 5 Pas) and 35.4 g of methyltrimethoxysilane (= 0.001 mole of F, 380 ppm of F, based on the weight of hydroxysi-loxane). After 10 minutes, deactivation was carried out with 2.7 ml of a 10% strength solution of aluminum tri-sec-butylate in THF
(0.001 mole of Al). It was found in the 29Si-NMR spectrum of the mixture that all the SiOH functions had been converted into Si-OSi(CH3)2CH3.
Example 15 0.2 ml of a 1.0 M solution of TBAF in THF was added to a mixture of 100 g of a polydimethylsiloxane having OH end groups and a vis-cosity of 1000 mm2/s and 7.4 g of methyltnmetho~silane at 75~C
(= 0.0002 mole of F, 42 ppm of F, based on the weight of hydroxysi-lo~ane). After 4 minutes, cros~linkin~ test on SiOH (aluminum sec-butylate) indicated complete co~ sion. Deactivation wa subse-quently carried out with 0.55 ml of a 10% strength solution of alumi-num tri-sec-butylate in THF (0.00022 mole of Al). It was found in the 29Si-NMR spectrum of the mixture that all the SiOH functions had been converted into Si-OSi(OCH3)2CH3.
Comparison E~cample 3 2 g of a solution of 2 g of NaOH in 47.5 of tetraethoxysilane and 0.5 g of ethanol (= 0.002 mole of NaOH) were added to a mixture of 163 g of a polydimethylsiloxane having OH end groups and a viscos-ity of 1000 mm2/s and 24.5 g of tetraethoxysilane. After 15 minutes, the base was neutralized with 0.2 g of dimethyldichlorosilane (= 0.0031 mole of Cl). All of the volatile components were subse-quently stripped off at 50~C/2 hPa. It was found in the 29Si-NMR
spectrum of the mixture, recorded after three days, that all the SiOH
functions had been converted into Si-OSi(OCH2CH3)3.
Comparison E~ample 4 Comparison Example 3 was repeated, with the difference that the volatile constituents were not distilled off after the neutr~li7~tic~n. It was found in the 29Si-NMR spectrum of the mixture recorded after three days that the desired triethoxysilyl end groups were present only in traces, and instead Si-OSi(CH3)2(0CH2CH3) functions which were not capable of crosslinking were chiefly detectable.
Example 16 A mixture of 90.9 g of melhylL,illlethoxysilane and 2.7 ml of 1.1 M
solution of TBAF in THF was added to 1000 g of a polydimethylsilox-ane having OH end groups and a viscosity of 80 Pas (0.003 mole of F, 56 ppm of F, based on the weight of hydroxysiloxane) in a planetary mixer. The mixture was stirred at room temperature for 25 minutes before deactivation was carried out with 24.3 g of a 10% strength solution of aluminum tri-sec-butylate in a polytdimethylsiloxane) blocked by trimethylsilyl end groups (= 0.01 mole of A1) which had a viscosity of 100 mm2/s. 524 g of this polydimethylsiloxane having trimethylsilyl end groups, 72.7 g of hexamethyl~ 7~ne, 254.4 g of a hydrophobic, pyrogenic silicic acid having a specific surface area of 120 m2/g and 4.91 g of dibutyltin diacetate were then mixed in suc-cession. Half of the paste obtained was cured in air in a layer thick-ness of 2 mm at room temperature for 14 days. An elastic vulcani-zate which gave the following mechanical values was obtained:
Tear strength (DIN 53504): 0.9 N/mm2 Elongation at break (DIN 53504): 340%
Tensile stress at 100% elongation (DIN 53504): 0.2 N/mm2 Tear propagation resistance (ASTM D 624 B-91): 4.3 N/mm2 Hardness (Shore A) (DIN 53505): 17 To investig~te the storage stability, the other half of the paste was protected from access of atmospheric humidity in polyethylene car-tridges. After storage at 50~C for 3 weeks, the paste showed no crosslinking phenomena when spread out, but then cured to an elastomer under the influence of atmospheric moisture.
Comparison Example 5 - (analogous to Example 1 of EP 468239 A2 cited above) 0.9 g of a solution of 2 g of NaOH in 47.5 g of melhyll,.~ethoxy-silane and 0.5 g of methanol (= 0.0009 mole of NaOH) was added to a mixture of 145 g of a polydimethylsiloxane having OH end groups and a viscosity of 1000 mm2/s (about 0.0178 mole of OH) and 10 g of methyltrimethoxysilane (0.0735 mole). After 5 minutes, the base was neutralized with 0.73 g of a solution of 5 g of dimethyldichlorosilane in 45 g of hexamethyldisiloxane (= 0.0011 mole of Cl). The mixture was then heated thoroughly at 140~Ct25 hPa for 2 hours. 132 g of a cloudy oil having a viscosity of 979 mm2/s remained as the residue.
The following average formula was obtained from the 29Si-NMR spec-trum of the product:
[MeSi(OMe)2Ol/2)2[SiMe2O]220. Blocking of the SiOH end groups was complete.
Compari~on E~ample 6 The procedure described in Comparison Example 5 was repeated, with the modification that the base was neutralized only after 10 minutes. 138 g of a cloudy oil having a viscosity of 427 mm2/s were obtained as the end product. The following average formula was 21~1985 obtained from the 29Si-NMR spectrum of the product:
[MeOSiMe2O~/2]2[Me(MeO)SiO][MeSiO3/2]05[SiMe2O]l,O. Although the blocking of SiOH end groups was complete, rearrangements to an extent such that the desired MeSi(OMe)2 end group was present only in traces had already taken place by lengthening the reaction time by 5 minutes compared with Comparison Example 5.
E~ample 17 C Preparation of catalyst solution F1 60 ml of 25% strength sulfuric acid were added to a solution of 17.4 g of potassium fluoride in 30 ml of completely demineralized water. After 30 minutes neutralization was carried out with 180 ml of an approximately 40% strength aqueous solution of tetra-n-butyl-ammonium hydroxide. The mixture was then extracted with 200 ml of THF. The extract was concentrated to dryness on a rotary evapora-lS tor and the residue was taken up on 300 ml of methyltrimethoxy-silane. Volatile constituents were then stripped off at 25~C/ 10 hPa.
The mixture was filtered. 192 g of a colorless, clear liquid having a fluoride content of 0.6 mole/l were obtained.
The advantage of this procedure lies in the fact that the hygroscopic tetrabutyl~mminium fluoride is practically dried with methyltri-methoxysilane. In the presence of the fluoride the residual moisture led to hydrolysis or condensation of the methyltrimethoxysilane.
Liquid oligomers of methyltrimethoxysilane and an insoluble precipi-tate of methylsilicic acid, which can be removed by simple filtration, 2s are formed.
0.2 ml of catalyst solution F1 described above under ~C) was added to a mixture of 100 g of a polydimethylsiloxane having OH end groups and a viscosity of 1000 mm2/s and 7.4 g of melhyll,imethoxy-silane (= 23 ppm of F, based on the weight of hydroxysiloxane) and the mixture was stirred for 20 minutes. The catalyst was deactivated by addition of 0.7 ml of a 10% strength solution of aluminum tri-sec-butylate in hexamethyldisiloxane. As a crosslinkin~ test showed (addition of aluminum tri-sec-butylate to small samples of the reac-214I9~5 tion mi~cture taken after certain intervals of time), all the SiOH groups had reacted in the desired sense after only 10 minutes (no further gelling with aluminum tri-sec-butylateJ. It was to be seen from the 29Si-NMR spectrum that all the OH end groups had been converted into H3CSi(OCH3)2- end groups.
Example 18 The procedure described in Example 17 was repeated, with the modification that 0.2 ml of catalyst solution F1 prepared in Example 17 under (C) (= 23 ppm of F, based on the weight of hydroxysiloxane) which had been stored at a temperature of 70~C in a polyethylene bottle for a period of 7 days was employed. As a cros~linkin~ test showed ~addition of aluminum tri-sec-butylate to small samples taken from the reaction mixture after certain intervals of time), all the SiOH groups had reacted in the desired sense after only 10 minutes ~no further gelling with aluminum tri-sec-butylate). It was to be seen from the 29Si-NMR spectrum that all the OH end groups had been converted into H3CSi(OCH)2- end groups.
Example 19 0.2 rnl of a 1.0 M solution of TBAF in THF was added to a mixture of 100 g of a polydimethy1~ilox~ne having OH end groups and a vis-cosity of 1000 mm2/s and 11.7 g of 2-cyanoethyltriethoxysilane (0.0002 mole of F, 38 ppm of F, based on the weight of hydroxysilox-ane). As a cros~linkin~ test showed (addition of aluminum tri-sec-butylate to small samples taken from the reaction mixture after cer-tain intervals of time), all the SiOH groups had reacted in the desired sense after only 10 minutes (no further gelling with alumi-num tri-sec-butylate). After this period of time, deactivation was carried out with 0.65 ml of a 10% sll~legth solution of aluminum tri-sec-butylate in hexamethyldisiloxane (0.00026 mole of Al). It was found in the 29Si-NMR spectrum of the mixture that all the SiOH
functions had been converted into Si-O-Si(OCH2CH3)2-(CH2)2-C~N and the ratio of end groups/dimethylsiloxy units had not changed com-pared with the starting value. The 29Si-NMR spectrum of a sample which had been subjected to storage under heat at 70~C in a dosed polyethylene bottle for 7 days showed no formation of monoethoxy end groups and/or branchings.
Example 20 0.1 ml of catalyst solution Fl described in Example 17 under C) was added to a mixture of 100 g of a polydimethylsiloxane having OH
end groups and a viscosity of 1000 mm2/s and 15.0 g of N-1~3-tri-ethoxysilyl)-propyl]-4,5-dihydroim~ 4le (commercially obtainable undcr the name"Dynasilan~ IMEO" from Hule AG, Marl) ~0.0006 mole of F, 11 ppm of F, based on the weight of hydroxyeil- Y~n~). Since no further gelling on samples taken occurred in the croselil.lnng test ac-cording to Example 19 with aluminum tri-sec-butylate after 20 min-utes, deactivation was carried out after this period of time with 0.16 ml of a 10% strength solution of aluminum tri-sec-butylate in hex-amethyldisiloxane (0.000065 mole of A1). It was found in the 29Si-NMR spectrum of the mixture that all the SiOH functions had been converted into Si-OSi(OCH2CH3)2-(CH2)3-N-dihydroimidazole and the ratio of end groups/dimethylsiloxy units had not changed compared with the starting value.
Example 21 0.2 ml of a 1.0 M solution of TBAF in THF was added to a mixture of 100 g of a polydimethylsiloxane having OH end groups and a vis-cosity of 1000 mm2/s and 0.9 g of N-l(3-triethoxysilyl)-propyll-4,5-dihydro-imidazole (commercially obtainable under the name ~Dyn~ n IMEO~ from Huls AG, Marl) and 7.6 g of vinyltriethoxy-silane (0.0002 mole of F, 38 ppm of F, based on the weight of hy-droxysiloxane). The end point of the reaction was determined by the crosslinkin~ test described in Example 19. Since no further gelling on samples taken occurred after 20 minutes, deactivation was carried out after this time with 0.65 ml of a 10% strength solution of alumi-num tri-sec-butylate in hexamethyldisiloxane (0.00026 mole of Al). It was found in the 29Si-NMR spectrum of the mixture that practically all the SiOH functions had been converted into ., ~, Si-OSi(OCH2CH3)2-CH=CH2 and the ratio of end groups/dimethyl-siloxy units had not changed compared with the starting value.
E~ample 22 0.2 ml of a 1.0 M solution of TBAF in THF was added to a mixture s of 100 g of a polydimethylsiloxane having OH end groups and a vis-cosity of 1000 mm2/s, 7.15 g of cyanoethyltriethoxysilane and 7.6 g of vi~ iethoxysilane (0.0002 mole of F, 38 ppm of F, based on the weight of hydroxysiloxane). The end point of the reaction was deter-mined by the crosslinkin~ test described in Example 19. Since no further gelling on samples taken occurred after 10 minutes, deactiva-tion was carried out after this time with 0.65 ml of a 10% strength solution of aluminum tri-sec-butylate in hexamethyl~ ilo~ne (0.00026 mole of Al). It was found in the 29Si-NMR spectrum of the mixture that 93.3% of all the SiOH functions had been converted into Si-OSi(OCH2CH3)2-CH2CH2-CN and 7.7% of all the SiOH functions had been COn~ led into Si-OSi(OCH2CH3)2-CH=CH2, and the ratio of end groups/dimethylsilo~y units had not changed compared with the starting value. The 29Si-NMR spectrum of a sample which had been subjected to storage under heat at 70~C in a closed polyethylene bottle for 7 days showed no formation of monoethoxy end groups and/or branchings.
Claims (10)
1. A process for the preparation of an organopolysiloxane which contains at least one unit of the formula (R1O)3-mRmSiO1/2 in which R is identical or different and is a hydrogen atom or monovalent, optionally substituted hydrocarbon radical, R1 is identical or different and is a monovalent, optionally substi tuted hydrocarbon radical having 1 to 8 carbon atoms and m is 0, 1 or 2, which comprises, in a 1st step, reacting an organosilicon compound (1) which contains at least one Si-bonded hydroxyl group with at least one silane (2) of the formula (R1O)4-mSiRm and/or a partial hydrolysate thereof, in which R, R1 and m have the above mentioned meaning, in the presence of a fluoride salt (3), and, optionally, in a 2nd step, when the reaction has ended, adding a component (4) which is capable of bonding fluoride ions.
2. A process as claimed in claim 1, where, in a 2nd step, when the reaction has ended, the component (4) capable of bonding fluoride ions is added.
3. A process as claimed in claim 1 wherein the organosilicon compound (1) containing at least one Si-bonded hydroxyl group is one chosen from the group consisting of organopolysiloxanes having at least one Si-bonded hydroxyl group and organosilanes having a hydroxyl group.
4. A process as claimed in claim 1, wherein the silane (2) and/or partial hydrolysate thereof is present in an amount of 1.01 to 10 mole per mole of Si-bonded hydroxyl groups of the compound (1).
5. A process as claimed in claim 1, wherein the fluoride salt (3) is one chosen from the group consisting of ammonium fluorides of the formula [R2 4N]F
in which R2 is identical or different and has one of the meanings given for R, adducts thereof with carbonyl compounds, (alkali) metal fluorides and organic or inorganic ammonium hydrogen fluorides, phosphonium fluorides, phosphonium hydrogen fluorides, tetrafluoroborates, hexafluorosilicates and fluorophosphates.
in which R2 is identical or different and has one of the meanings given for R, adducts thereof with carbonyl compounds, (alkali) metal fluorides and organic or inorganic ammonium hydrogen fluorides, phosphonium fluorides, phosphonium hydrogen fluorides, tetrafluoroborates, hexafluorosilicates and fluorophosphates.
6. A process as claimed in claim 5, wherein the fluoride salt (3) is an ammonium fluoride of formula (III).
7. A process as claimed in claim 1, wherein the fluoride salt (3) is present in an amount of 0.1 to 1000 ppm (parts by weight per million parts by weight), calculated as elemental fluorine and based on the total weight of hydroxy-functional organosilicon compound (1).
8. A process as claimed in claim 2, wherein component (4) is an aluminum compound or complex.
9. A process as claimed in claim 8, wherein component (4) is an aluminum alcoholate.
10. A process as claimed in claim 8, wherein the aluminum compound or complex is present in an amount of 1.05 to 3 mole of aluminum per mole of fluoride of component (3).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4405851A DE4405851A1 (en) | 1994-02-23 | 1994-02-23 | Process for the preparation of organopolysiloxanes containing organyloxy groups |
| DEP4405851.9 | 1994-02-23 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2141985A1 CA2141985A1 (en) | 1995-08-24 |
| CA2141985C true CA2141985C (en) | 1999-01-12 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002141985A Expired - Fee Related CA2141985C (en) | 1994-02-23 | 1995-02-07 | Process for the preparation of organopolysiloxanes containing organyloxy groups |
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| Country | Link |
|---|---|
| EP (1) | EP0672702B1 (en) |
| JP (1) | JP2677773B2 (en) |
| KR (1) | KR0144238B1 (en) |
| CN (1) | CN1037003C (en) |
| AT (1) | ATE140018T1 (en) |
| AU (1) | AU684873B2 (en) |
| BR (1) | BR9500728A (en) |
| CA (1) | CA2141985C (en) |
| DE (2) | DE4405851A1 (en) |
| ES (1) | ES2089928T3 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0652245B2 (en) * | 1993-11-05 | 2005-02-09 | Shin-Etsu Chemical Co., Ltd. | Process for preparing organic functional group-containing organopolysiloxanes, organopolysiloxanes obtained by the process and mercapto group and alkoxy group-containing organopolysiloxanes and preparation thereof |
| DE4436536A1 (en) * | 1994-04-20 | 1995-10-26 | Bayer Ag | Process for the preparation of reaction products of poly (diorganosiloxanes) |
| ATE189687T1 (en) * | 1994-04-20 | 2000-02-15 | Ge Bayer Silicones Gmbh & Co | METHOD FOR PRODUCING IMPACT PRODUCTS FROM POLY(DIORGANOSILOXANES) |
| JPH08104753A (en) * | 1994-10-06 | 1996-04-23 | Shin Etsu Chem Co Ltd | Production of organopolysiloxane |
| KR100533538B1 (en) * | 2002-12-03 | 2005-12-05 | 삼성전자주식회사 | Compsoition for Preparing Porous Interlayer Dielectric Thin Film, Containing Novel Pore-Generating Material |
| DE102004014216A1 (en) * | 2004-03-23 | 2005-10-13 | Wacker-Chemie Gmbh | Crosslinkable compositions based on organosilicon compounds |
| DE102005047394A1 (en) * | 2005-10-04 | 2007-04-05 | Wacker Chemie Ag | Production of organopolysiloxane for use e.g. in buildings protection, involves reaction of chlorosilane with water and alcohol, continuous addition of water and immiscible solvent, and then phase separation |
| TWI434890B (en) * | 2007-04-06 | 2014-04-21 | Shinetsu Chemical Co | Addition curable silicone resin composition and silicone lens using same |
| DE102007020568A1 (en) * | 2007-05-02 | 2008-11-06 | Wacker Chemie Ag | Process for the continuous preparation of aminoalkyl-containing organopolysiloxanes |
| DE102007020569A1 (en) * | 2007-05-02 | 2008-11-06 | Wacker Chemie Ag | Process for the preparation of aminoalkylpolysiloxanes |
| NO20073388L (en) * | 2007-07-02 | 2009-01-05 | Jotun As | Organofunctional polysiloxane polymers and coating compositions containing said polymers |
| US9250357B2 (en) * | 2013-03-15 | 2016-02-02 | Johnson & Johnson Vision Care, Inc. | Silicone-containing contact lens having reduced amount of silicon on the surface |
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| CA1327207C (en) * | 1987-08-27 | 1994-02-22 | Jeffrey Hayward Wengrovius | Polyalkoxysilyl-terminated polydiorganosiloxanes, methods for their preparation, and room temperature vulcanizable compositions containing them |
| EP0576166A2 (en) * | 1992-06-08 | 1993-12-29 | General Electric Company | Heat curable silicone hardcoat compositions |
-
1994
- 1994-02-23 DE DE4405851A patent/DE4405851A1/en not_active Withdrawn
- 1994-12-29 CN CN94113449A patent/CN1037003C/en not_active Expired - Fee Related
-
1995
- 1995-02-07 CA CA002141985A patent/CA2141985C/en not_active Expired - Fee Related
- 1995-02-20 AU AU12363/95A patent/AU684873B2/en not_active Ceased
- 1995-02-21 KR KR1019950003384A patent/KR0144238B1/en not_active IP Right Cessation
- 1995-02-21 JP JP7032551A patent/JP2677773B2/en not_active Expired - Lifetime
- 1995-02-22 BR BR9500728A patent/BR9500728A/en not_active Application Discontinuation
- 1995-02-23 DE DE59500004T patent/DE59500004D1/en not_active Expired - Fee Related
- 1995-02-23 EP EP95102568A patent/EP0672702B1/en not_active Expired - Lifetime
- 1995-02-23 ES ES95102568T patent/ES2089928T3/en not_active Expired - Lifetime
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| Publication number | Publication date |
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| DE59500004D1 (en) | 1996-08-08 |
| ATE140018T1 (en) | 1996-07-15 |
| CN1108268A (en) | 1995-09-13 |
| AU684873B2 (en) | 1998-01-08 |
| KR0144238B1 (en) | 1998-07-15 |
| AU1236395A (en) | 1995-08-31 |
| CA2141985A1 (en) | 1995-08-24 |
| JP2677773B2 (en) | 1997-11-17 |
| ES2089928T3 (en) | 1996-10-01 |
| EP0672702B1 (en) | 1996-07-03 |
| BR9500728A (en) | 1995-10-31 |
| JPH07258413A (en) | 1995-10-09 |
| CN1037003C (en) | 1998-01-14 |
| EP0672702A1 (en) | 1995-09-20 |
| KR950025053A (en) | 1995-09-15 |
| DE4405851A1 (en) | 1995-08-31 |
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