DE4029481A1 - New organo-poly:siloxane prods. with terminal siloxane units - Google Patents

Abstract

Organo(poly)siloxanes (I) with terminal siloxane units having organyloxy and hydrogen gps. are claimed. Organo(poly)siloxane compsns. (II) crosslinkable to form elastomers by splitting off an alcohol, contg. at least one (I). (1) Prepn. of (I) by reacting alpha, omega-dihydroxy organo(poly) siloxane of formula (1) with silane of formula (2). In the formulae R, R1, R2 (same or different) = monovalent, opt. substd. hydrocarbon gp.; X = gp. readily split off; n = at least 2; a = 1 or 2. (2) Crosslinking (I) through moisture. (3) Prepn. of (II) by (a) mixing together all constituents in any desired order (b) stirring at 15-80 deg C and 900-1100 hPa pressure for 20-90 mins.. (c) stirring further at 0.01-100 hPa pressure for 3-60 mins. rate of stirring being such that temp. of mixt. rises to level in range 15-80 deg C without addn. of heat. (4) Prepn. of organopolysiloxane elastomers by crosslinking compsn. crosslinkable through addn. of Si-bound H in SiC-linked organic gp. with aliphatic C-C multiple bond and contg. at least one (I).

Description

The invention relates to organo (poly) siloxane compositions, which under Exclusion of water are storable when water is entered however at room temperature with the elimination of alcohol len can be crosslinked to form elastomers and a process for the production of such masses.

From U.S. Patent 4,755,578 (General Electric Company; issued on July 5, 1988) organopolysiloxane compositions are already known, which can be crosslinked to form elastomers by splitting off alcohols are. Furthermore, in DE-OS 38 01 389 (Wacker-Chemie GmbH; issued on July 27, 1989) or the corresponding U.S. application with serial number U.S.S.N. 2 93 909 (pending on January 6, 1989) with the elimination of alcohols Describing elastomer crosslinkable organopolysiloxane compositions which is branched by salts of the 2nd main and subgroup chain carboxylic acids are stabilized.

However, such masses are generally very small Networking speed on, so that for acceleration Metal compounds, such as tin compounds, as Condensation catalyst must be added. Thereby however, storage stability is often impaired that such masses no longer or only after prolonged storage harden very slowly.

The object of the present invention was to split off crosslinkable from alcohols to elastomers To provide organo (poly) siloxane compositions, which under Aus closure of water for a long time without significant change their desired properties can be stored and when water enters elastomers in a relatively short time network. It was also an object of the present invention a method of making such To provide organo (poly) siloxane compositions. These tasks are solved by the present invention.

The invention relates to the elimination of alcohols Organo (poly) siloxane compositions which can be crosslinked to form elastomers, characterized in that they have at least one Organo (poly) siloxane with alkoxy and hydrogen groups send, containing terminal siloxane units.

With the organo (poly) siloxane used according to the invention Terminal, having alkoxy and hydrogen groups Siloxane units are preferably those of the formula

wherein
R, R ¹ and R ^{2 can,} independently of one another, be the same or different and represent a monovalent, optionally substituted hydrocarbon radical, preferably a monovalent, optionally substituted hydrocarbon radical having 1 to 13 carbon atoms,
n is an integer of at least 2, preferably between 10 and 2500, particularly preferably between 10 and 2000, in particular between 20 and 1500, and
a is 1 or 2, preferably 2.

Although not represented by formula (I), up to 10 mole percent of the diorganosiloxane units can be replaced by other siloxane units, such as RSiO _3/2 and / or SiO _4/2 units, where R has the meaning given above. Furthermore, the organo (poly) siloxanes according to formula (I) - although also not shown in formula (I) - can contain up to 20 mol percent of other functional groups, such as hydroxyl groups, for production reasons.

Examples of hydrocarbon residues with 1 to 13 coals Substance atoms are alkyl radicals, such as the methyl, ethyl, n- Propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, n- Pentyl, iso-pentyl, neo-pentyl, tert-pentyl, hexyl residues, such as the n-hexyl residue, heptyl residues, such as the n-heptyl residue, octyl residues, such as the n-octyl residue and iso-octyl residues, such as the 2,2,4-trimethylpentyl residue, nonyl residues such as the n-No nyl radical, decyl radicals, such as the n-decyl radical, dodecyl radicals, such as the n-dodecyl radical; Alkenyl residues, such as the vinyl and the Al lylrest; Cycloalkyl radicals, such as cyclopentyl, cyclohexyl, cy cloheptyl and methylcyclohexyl; Aryl residues like that Phenyl and naphthyl; Alkaryl residues, such as o-, m-, p- Tolyl, xylyl and ethylphenyl; Aralkyl residues, such as the benzyl radical, the alpha and the β-phenylethyl radical.

Examples of substituted hydrocarbon radicals are Alkoxyalkyl radicals, such as the methoxyethyl radical, haloalkyl residues such as the trifluoropropyl residue and acyloxyalkyl residues such as the acetoxyethyl radical.

The radical R is particularly preferably alkyl groups, which are optionally substituted by alkyl groups can be, especially around methyl groups.  

The radical R ¹ is particularly preferably alkyl groups, in particular ethyl groups.

The radical R ² is particularly preferably alkyl groups, which may optionally be substituted by alkyl groups, in particular methyl groups.

Examples of the organo (poly) siloxanes according to the invention with terminal siloxane units containing alkoxy and hydrogen groups are
α, ω-bis (hydrogendimethoxysiloxy) dimethyl (poly) siloxanes,
α, ω-bis (hydrogendiethoxysiloxy) dimethyl (poly) siloxanes,
α, ω-bis (hydrogenmethoxymethylsiloxy) dimethyl (poly) siloxanes,
α, ω-bis (hydrogenethoxymethylsiloxy) dimethyl (poly) siloxanes and α, ω-bis (hydrogendiethoxysiloxy) dimethyl / methylvinyl co (poly) siloxanes.

The organo (poly) siloxanes of the formula (I) at a temperature of 23 ° C. have a viscosity of preferably 2 to 10 ⁷ mPa · s, particularly preferably of 1000 to 400,000 mPa · s.

With the organo (poly) siloxane used according to the invention Terminal, having alkoxy and hydrogen groups Siloxane units are particularly preferably α, ω-bis (hydrogendiethoxysiloxy) dimethyl (poly) siloxane and α, ω-bis (hydrogenethoxymethylsiloxy) dimethyl (poly) siloxanes as well as their mixtures, especially around α, ω-bis (hydrogendiethoxysiloxy) dimethyl (poly) siloxanes.

Organo (poly) siloxanes with alkoxy and hydrogen groups send, terminal siloxane units and methods for their Manufacturing are already from the German application with the Case number P 40 13 281.1 (G. Staiger, Wacker-Chemie GmbH; filed on April 26, 1990).  

Although not specified in formula (I), the fiction according to the organo (poly) siloxanes used for the production to a small extent too

contain, wherein R¹ and R ^{2 have} the meaning given above.

Preferably, the present invention contains under treatment of alcohols to form elastomers Organo (poly) siloxane compositions in addition to the invention set organo (poly) siloxane with alkoxy and hydrogen group-containing terminal siloxane units at least one hydride-functional alkoxysilane, preferably that of the formula

wherein R ^{3 has} a meaning given for R ¹ , R ^{4 has} a meaning given for R ² and b is 2 or 3. If the organo (poly) siloxane with hydrogen and alkoxy groups used according to the invention has terminal siloxane units which are a low molecular weight organo (poly) siloxane, such as those with a molecular weight of less than 35,000 g / mol, can be used in the Crosslinkable organo (poly) siloxane compositions according to the invention can be dispensed with silane of the formula (II).

Examples of hydride-functional alkoxysilanes according to the formula (II) are hydrogen triethoxysilane, hydrogen trimethoxysilane, Hydrogen tri (n-propyloxy) silane, hydrogen methyl diethoxysilane,  Hydrogenmethyldimethoxysilane and hydrogenmethyldi (n- propyloxy) silane.

The components other than that used in the present invention Organo (poly) siloxane with alkoxy and hydrogen groups send, terminal siloxane units and if necessary hydride-functional alkoxysilane used in the inventive splitting off alcohols to elasto the same crosslinkable organo (poly) siloxane compositions be as they have been in the under-splitting of alcohols organo (poly) siloxane compositions which can be crosslinked to give elastomers could lie, with basic ingredients less are suitable because they reduce the storage stability.

Examples of such other components are silanes formula

R⁶ _c Si (OR⁵) _4-c (III)

wherein R ^{5 has} a meaning given for R ¹ , R ^{6 has} a meaning given for R ² and c is 0 or 1, or their partial hydrolyzates, such as hexamethoxydisiloxane, condensation catalysts, reinforcing inorganic fillers, non-reinforcing inorganic fillers, pigments, soluble dyes , perfumes, softeners, such as liquid at room temperature, by trimethylsiloxy endblocked dimethylpolysiloxanes or organophosphate, fungicides, resinous organopolysiloxanes, including those of (CH _{3) 3} SiO _1/2 - and SiO _4/2 units, purely organic resins such as homopolymers - or copolymers of acrylonitrile, styrene, vinyl chloride or propylene, corrosion inhibitors, polyglycols, which may be esterified and / or etherified, oxidation inhibitors, heat stabilizers, solvents, agents for influencing the electrical properties, such as conductive carbon black, flame retardants, light stabilizers Extension means d he skin formation time, such as silanes with a SiC-bonded mercaptoalkyl radical, cell-generating agents, for. B. azodicarbonamide, thixotropic agent, adhesion promoters, such as aminoalkyl or glycidoxypropyl-functional silanes or organo (poly) siloxanes, and scavengers.

Preferably, the present invention contains under processing of alcohol-crosslinkable organo (poly) siloxane compositions, each based on the total weight of the crosslinkable Organo (poly) siloxane mass,

• A) 20 to 80 percent by weight, preferably 30 to 70 percent by weight percent, organo (poly) siloxane with alkoxy and hydrogen group-containing terminal siloxane groups according to Formula (I),
• B) 0 to 30 percent by weight, preferably 2 to 10 percent by weight percent, hydride-functional alkoxysilane according to formula (II),
• C) 0 to 5 percent by weight, preferably 0 to 2 percent by weight percent, condensation catalyst,
• D) 0 to 70 percent by weight, preferably 8 to 60 percent by weight percent, filler,
• E) 0 to 60 percent by weight, preferably 0 to 50 percent by weight percent, plasticizer,
• F) 0 to 20 percent by weight, preferably 0.5 to 10 percent by weight percent, adhesion promoter,
• G) 0 to 20 percent by weight, preferably 0 to 7 percent by weight percent, scavenger as well  
• H) optionally other substances, such as color substances, fungicides and thixotropic agents.

Component (B) is preferably hy Dridfunctional diethoxy or triethoxysilane and their Mixtures, the preferred mixing ratio of which desired mechanical properties is determined.

As a condensation catalyst (C) appropriate masses contain any condensation catalysts ten, so far in the absence of water storable, with access to water at room temperature Elastomer crosslinking masses could be present, such as for example (organo) metal compounds, acidic catalysts goals such as B. carboxylic acids, and basic catalysts, such as B. amine.

Acid is preferred among these condensation catalysts Catalysts, such as carboxylic acids, where Car bonic acids, such as hexanoic acid, 2-ethylhexanoic acid, Lauric acid, malonic acid and oleic acid, particularly preferred be used.

Compounds can also be used as component (C) are used, which only when water enters their Develop effect as acid catalysts, such as wise carboxylic acid anhydrides, acyloxysilanes and carbetoxysila ne, such as acetoxysilanes.

Examples of the fillers (D) used in the organo (poly) siloxane compositions according to the invention are non-reinforcing fillers, i.e. fillers with a BET surface area of up to 50 m ² / g, such as quartz, diatomaceous earth, calcium silicate, zirconium silicate, zeolites, metal oxide powder , such as aluminum, titanium, iron or zinc oxides or their mixed oxides, barium sulfate, calcium carbonate, gypsum, silicon nitride, silicon carbide, boron nitride, glass and plastic powder, such as polyacrylonitrile powder; reinforcing fillers, ie fillers with a BET surface area of more than 50 m ² / g, such as pyrogenic silica, precipitated silica, carbon black, such as furnace black and acetylene black and silicon-aluminum mixed oxides having a large BET surface area; fibrous fillers such as asbestos and plastic fibers. The fillers mentioned can be rendered hydrophobic, for example by treatment with organosilanes or organosiloxanes or with stearic acid or by etherification of hydroxyl groups to alkoxy groups.

Examples of those in the invention Organo (poly) siloxane masses plasticizers (E) are used liquid at room temperature, by trimethylsiloxy groups end-blocked dimethylpolysiloxanes and high-boiling coals hydrogen.

Examples of those in the invention Organo (poly) siloxane masses used adhesion promoter (F) are silanes and organo (poly) siloxanes with a functional group pen, such as aminoalkyl, glycidoxypropyl or Methacryloxypropyl residues.

Suitable as scavengers (G) are all compounds which are in are able to maintain the storage stability of the invention Organo (poly) siloxane-reducing molecules, such as for example, to intercept water, alcohol or silanols.

Examples of such scavengers (G) are silanes of the formula

R⁷ _4-d SiX _d (IV)

wherein R ^{7 may be the} same or different and has one of the meanings of R, X is an easily removable group, such as

where R⁸, R⁹ and R¹⁰ are each the same or can be different and an organic radical mean, d is 1, 2, 3 or 4, such as triacet oxymethylsilane, di (N-methylacetamido) dimethylsilane and Diacetoxydimethylsilane, and carboxylic anhydrides, carbon acid esters, isocyanates, molecular sieves and unsaturated organic compounds according to US Pat. No. 4,489,191 (General Electric Company; issued December 18, 1989).

In the individual components of the invention under Cleavage of alcohols crosslinkable Organo (poly) siloxane compositions can each be one type such components as well as a mixture of min act at least two types of such components.

All can be used to prepare the compositions according to the invention Components of the respective mass in any order be mixed together. This mixing takes place before preferably at room temperature. If desired, this can be done Mixing also take place at higher temperatures, e.g. B. at temperatures in the range of 35 ° C to 135 ° C. Preferably with this mixing, the access of water as far as possible excluded.

According to a preferred embodiment of the invention Process for the preparation of the compositions according to the invention all components are included in any order mixed, the mixture in a 1st stage at a Temperature of preferably 15 to 80 ° C, especially before pulls 40 to 50 ° C, and a pressure of preferably 900 to 1100 hPa for a period of preferably 20 to 90 minutes,  particularly preferably 30 to 60 minutes, stirred and then in a second stage at a pressure of preferential as 0.01 to 100 hPa, particularly preferably 1 to 1 rhPa, for a period of preferably 3 to 60 minutes, especially preferably 5 to 30 minutes, stirred further, the stirring speed is chosen so that the temperature of the Mass while stirring without adding any heat to one Value within the above preferred temperature range rich increases.

For the crosslinking of the compositions according to the invention, the is sufficient usual water content of the air. Networking can if desired, even at higher or lower temperatures doors than room temperature, e.g. B. at -5 ° to 10 ° C or at 30 ° up to 50 ° C.

The present invention with the elimination of alcohols Elastomer crosslinkable organo (poly) siloxane compositions have the Advantage that they are characterized by a high networking speed Distinguishability and high storage stability. The white Tere have the according to the inventive method Organo (poly) siloxane compositions produced the advantage that they No hydrogen evolution even after long storage demonstrate.

The compositions of the invention can be used for all purposes Purposes are used for the exclusion of water storable, with access to water at room temperature Elastomer crosslinking compositions can be used.

The compositions of the invention are therefore extremely suitable for example as sealants for joints, including vertical joints, and similar empty spaces of e.g. B. 10 to 40 mm clear width, z. B. of buildings, rural, Water and aircraft, or as adhesives or kits  tion masses, e.g. B. in window construction or in the production of Aquariums or showcases, as well as e.g. B. for the production of Protective covers, including those for permanent use Exposure to surfaces exposed to fresh or sea water, or slip-resistant covers, or rubber elastic moldings and for the insulation of elec trical or electronic devices.

In the examples described below refer to all viscosity data at a temperature of 25 ° C. Like this Unless otherwise stated, the following examples are used play at a pressure of the surrounding atmosphere, so about at 1000 hPa, and at room temperature, i.e. at about 23 ° C, or at a temperature that changes when the Reactants at room temperature without additional heating or Cooling set, performed. Furthermore refer to all details of parts and percentages, insofar as nothing otherwise specified is by weight.

In the following examples, Shore A hardness according to DIN (German industry standard) 53 505-87, the tensile strength, the Elongation at break and the module (tensile strength after 100% Elongation) according to DIN 53 504-85S1 and the tear propagation strength determined according to ASTM D624B-73.

The abbreviation also means rev / min revolutions / minute.

example 1

A) Preparation of α, ω-di (diethoxyhydrogen) dimethyl polysiloxane (polymer I).

500 g of an α, ω-dihydro xydimethylpolysiloxane with a viscosity of about 80,000 mPas and an average of 900 to 1000 dimethylsiloxy units with 20 g of hydrogen triethoxysilane and 1.6 g of 2-ethylhexanoic acid are heated at 70 ° for 30 minutes under nitrogen on a rotary evaporator C. heated. Excess silane is then distilled off at a pressure of 0.1 to 1.5 kPa. In the ²⁹ Si NMR spectrum it can be seen that the end blocking of the silanol groups has run off quantitatively.

In a 5 l planetary mixer (type FH6-S from Drais-Werke GmbH, D-6800 Mannheim) 52 parts of Polymer I, 30 parts α, ω-Di (trimethylsiloxy) dimethylpolysiloxane with a visco sity of about 100 mPa · s, 14.5 parts of pyrogenic silica (available as HDK H 15 from Wacker-Chemie GmbH, D-8000 Munich) and 0.3 part of 2-ethylhexanoic acid within 5 Minutes homogeneously mixed at a speed of 120 rpm. The mass obtained in this way is excluded from moisture Bottles filled and stored at a temperature of 50 ° C. Information on storage stability can be found in Table 1.

The mass obtained in this way becomes after one day or 30 days Storage exposed to humidity. The time until Formation of a dry surface (skin formation time) can be found in Table 1.

Example 2

The procedure given in Example 1 is repeated with the modification that instead of 14.5 parts 14.0 parts fumed silica are used and an additional 5.0 Parts of hydrogen triethoxysilane are added. Information about the storage stability and skin formation times can be found in Table 1.  

Example 3

The procedure described in Example 2 is again brings with the modification that the mixing of the ingredients instead of 5 minutes at a speed of 120 rpm 35 minutes at a speed of 160 rpm and at one Temperature of 45 ° C is carried out, followed by the mixture for a further 10 minutes at a speed of 160 rpm further stirred at a pressure of 0.1 to 1.5 kPa becomes. Information about storage stability and skin formation time can be found in Table 1.

Example 4

In a 5 l planetary mixer (type FH6-S from Drais-Werke GmbH, D-6800 Mannheim) are 51 parts of the in Example 1 Polymer I described under A), 30 parts α, ω-Di (trimethylsiloxy) dimethylpolysiloxane with a viscosity of 100 mPas, 6 parts hydrogen triethoxysilane, 0.3 parts 2- Ethylhexanoic acid, 35 parts dolomite (available under the Description Microdol S at Norwegian Talc Minerals A.S., N- 5355 Knarrevik) and 12 parts fumed silica (obtained H 15 from Wacker-Chemie GmbH, D-8000 Munich) within 5 minutes at a speed of 120 rpm mixed. Furthermore, it is described as in Example 1 method. Information on storage stability and skin bil times are shown in Table 1.

Example 5

The procedure described in Example 4 is again brings with the modification that the mixing of the ingredients instead of 5 minutes at a speed of 120 rpm  10 minutes at a speed of 160 rpm at a tempe temperature of 45 ° C and a pressure of 0.1 to 1.5 kPa leads. Information on storage stability and Skin formation times can be found in Table 1.

Example 6

The procedure described in Example 4 is again brings with the modification that the mixing of the ingredients instead of 5 minutes at a speed of 120 rpm 35 minutes at a speed of 160 rpm at a tem temperature of 45 ° C is carried out, followed by the mixture for a further 10 minutes at a speed of 160 rpm stirred at a pressure of 0.1 to 1.5 kPa becomes. Information about storage stability and skin formation time can be found in Table 1.

Table 1

Example 7

α, ω-dihydroxydimethylpolysiloxane with a viscosity of about 20,000 mPa · s with 3% hydrogen triethoxysilane, bezo gene on the weight of α, ω-dihydroxydimethylpo used lysiloxane, heated at 80 ° C for 1 h. Then at one Temperature between 85 and 100 ° C on a rotary evaporator well heated to a pressure of 1.0 kPa. After removing excess silane and fission products are again 5% Hydrogen triethoxysilane, based on the weight set α, ω-dihydroxydimethylpolysiloxane added.

The silane-siloxane mixture thus obtained is now in each case added to the additives listed in Table 2.

Part of the resulting masses becomes the Exposed to humidity. The times to train one dry surface (skin formation time) can be found in Ta belle 2. Another part of these masses becomes moist Exclusion in tubes and at a temperature stored at 50 ° C. Find information about storage stability in Table 2.  

Table 2

Example 8

In a 5 l planetary mixer (type FH6-S from Drais-Werke, D-6800 Mannheim) 51 parts of the in Example 1 under A) polymer I described, 30 parts α, ω- di (trimethylsiloxy) dimethylpolysiloxane with a viscosity of 100 mPa · s, 6 parts hydrogen triethoxysilane, 0.60 parts Oleic acid, 35 parts dolomite (available under the name Microdol S at Norwegian Talc Minerals A.S., N-5355 Knarrevik), 12 parts fumed silica (available as H 15 from Wacker-Chemie GmbH, D-8000 Munich) and each 1.35 parts of the substance shown in Table 3 within of 35 minutes at a speed of 160 rpm at a Temperature mixed from 45 to 50 ° C, followed by the mixture for a further 10 minutes at a speed of 160 rpm is stirred at a pressure of 1 to 2 kPa. With the masses obtained in this way are described as in Example 1 method. Information on storage stability and skin bil times can be found in Table 3.

Table 3

Example 9

In a 5 l planetary mixer (type FH6-S from Drais-Werke, D-6800 Mannheim) 51 parts of the in Example 1 under A) polymer I described, 30 parts α, ω- di (trimethylsiloxy) dimethylpolysiloxane with a viscosity of 100 mPas, 6.00 parts hydrogen triethoxysilane, 0.60 parts Oleic acid, 35 parts dolomite (available under the name Microdol S at Norwegian Talc Minerals A.S., N-5355 Knarrevik) and 12 parts fumed silica (available as H 15 from Wacker-Chemie GmbH, D-8000 Munich) within of 35 minutes at a speed of 160 rpm at a Temperature mixed from 45 to 50 ° C, followed by the mixture for a further 10 minutes at a speed of 160 rpm is stirred at a pressure of 1 to 2 kPa. The mass obtained in this way is excluded from moisture Bottles filled and stored at a temperature of 50 ° C. There is none within 30 days of manufacture To observe hydrogen evolution.

The mass obtained in this way becomes after one day or 30 days of storage produced 2 mm thick films by the Measure each with a spatula on a surface Polytetrafluoroethylene applied and the humidity  is exposed. Two weeks after application, the created dry films on their mechanical properties researched. Mechanical details Properties can be found in Table 4.

Skin formation time (min) after storage of
1 d: 17
30 d: 17.

Example 10

According to the procedure described in Example 9 from 52 parts of the poly described in Example 1 under A) mer I, 30 parts of α, ω-di (trimethylsiloxy) dimethylpolysiloxane with a viscosity of 100 mPa · s, 5.20 parts hydrogen triethoxysilane, 0.50 parts oleic acid and 13.5 parts pyroge ner silica (available as H 15 from Wacker-Chemie GmbH, D-8000 Munich) produced a mass. Furthermore the procedure is as described in Example 9. Information about the mechanical properties can be found in Table 4.

Skin formation time (min) after storage of
1 d: 9
30 d: 15.

Example 11

According to the procedure described in Example 9 from 52 parts of the poly described in Example 1 under A) mer I, 30 parts of α, ω-di (trimethylsiloxy) dimethylpolysiloxane with a viscosity of 100 mPa · s, 5.20 parts Hydrogendi ethoxymethylsilane, 0.40 parts oleic acid and 12.0 parts pyro Generic silica (available as H 15 from Wacker-Chemie  GmbH, D-8000 Munich) produced a mass. Furthermore the procedure is as described in Example 9. Information about the mechanical properties can be found in Table 4.

Skin formation time (min) after storage of
1 d: 45
30 d: 40.

Example 12

A) Preparation of α, ω-di (ethoxymethylhydrogen) dimethyl polysiloxane (polymer II)

500 g of an α, ω-dihydro xydimethylpolysiloxane with a viscosity of about 80,000 mPa · s and an average of 900 to 1000 dimethylsiloxy units with 40 g of hydrogendiethoxymethylsilane and 2.5 g of 2-ethylhexanoic acid are heated at 80 ° C. for 4 hours on a rotary evaporator heated. Excess silane is then distilled off at a pressure of 0.1 to 1.5 kPa. In the ²⁹ Si NMR spectrum it can be seen that the end blocking of the silanol groups has run off quantitatively.

According to the procedure described in Example 9 from 52 parts of Polymer II, 30 parts α, ω-Di (trimethylsiloxy) dimethylpolysiloxane with a viscosity of about 100 mPa · s, 5.20 parts hydrogen triethoxysilane, 12.0 Parts of fumed silica (available as HDK H 15 from Wacker-Chemie GmbH, D-8000 Munich) and 0.4 parts Oleic acid made a mass. Furthermore, as in Procedure described in Example 9. The resulting dry Films have a brittle character.  

Skin formation time (min) after storage of
1 d: 10
30 d 8.

Example 13

The procedure described in Example 12 is again with the modification that instead of 52 parts of polymer II a mixture of 26 parts of polymer I and 26 parts of poly mer II is used. Information about the mechanical properties The resulting dry films can be found in Table 4.

Skin formation time (min) after storage of
1 d: 10
30 d: 11.

Table 4

Claims (6)

1. With the elimination of alcohols to form elastomers, crosslinkable organo (poly) siloxane compositions, characterized in that they contain at least one organo (poly) siloxane with terminal siloxane units containing alkoxy and hydrogen groups. 2. With the elimination of alcohols to form elastomers, vernetzba re organo (poly) siloxane compositions according to claim 1, characterized in that as the organo (poly) siloxane having alkoxy and hydrogen groups having terminal siloxane units of the formula is used, in which
R, R ¹ and R ² can each independently be the same or different and denote a monovalent, optionally substituted hydrocarbon radical,
n is an integer of at least 2 and
a is 1 or 2. 3. With the elimination of alcohols to form elastomers re organo (poly) siloxane compositions according to claim 1 or 2, characterized in that they additionally at least contain a hydride-functional alkoxysilane. 4. With the elimination of alcohols to form elastomers, vernetzba re organo (poly) siloxane compositions according to claim 3, characterized in that the hydride-functional alkoxysilane of the formula is used, whereby
R ³ and R ⁴ can each independently be the same or different and mean a monovalent, optionally substituted hydrocarbon radical and
b is 2 or 3. 5. With the elimination of alcohols to form elastomers, crosslinkable organo (poly) siloxane compositions according to one or more of claims 1 to 4, characterized in that, based in each case on the total weight of the crosslinkable organo (poly) siloxane composition,

• A) 20 to 80 percent by weight of organo (poly) siloxane with terminal siloxane groups of the formula (I) having alkoxy and hydrogen groups,
• B) 0 to 30 percent by weight of hydride-functional alkoxy silane according to formula (II),
• C) 0 to 5 percent by weight of condensation catalyst,
• D) 0 to 70 percent by weight filler,
• E) 0 to 60 percent by weight plasticizer,
• F) 0 to 20 percent by weight of adhesion promoter,
• G) 0 to 20 weight percent scavenger as well
• H) optionally contain other substances such as dyes, fungicides and thixotropic agents.

6. Process for the production of Alko bring to crosslinkable elastomers Organo (poly) siloxane compositions according to one or more of the Claims 1 to 5, characterized in that all Components with each other in any order are mixed, the mixture in a 1st stage a temperature of 15 to 80 ° C and a pressure of 900 to 1100 hPa for a period of 20 to 90 minutes is stirred and then in a second stage a pressure of 0.01 to 100 hPa for a period of is preferably stirred for 3 to 60 minutes, wherein the stirring speed is chosen so that the Temperature of the mass during stirring without further Heat input to a value within the above preferred temperature range increased.