EP1448713A2

EP1448713A2 - Polyorganosiloxane compositions which can be painted or coated over

Info

Publication number: EP1448713A2
Application number: EP02787735A
Authority: EP
Inventors: Markus Putzer
Original assignee: GE Bayer Silicones GmbH and Co KG
Current assignee: Momentive Performance Materials GmbH
Priority date: 2001-11-21
Filing date: 2002-11-20
Publication date: 2004-08-25
Also published as: AU2002352061A1; DE10156918A1; AU2002352061A8; US20050054765A1; WO2003044092A2; WO2003044092A3

Abstract

The invention relates to a polyorganosiloxane composition, which is obtained by means of a method comprising the mixing and reacting of given components, a vulcanized elastic polyorganosiloxane composition, which is obtained by reacting the polyorganosiloxane compositions through contact with water or water vapor and the use of the vulcanized polyorganosiloxane compositions as joint sealings, adhesives, profiles, coatings or formed-in-place gaskets.

Description

Paint-compatible to paintable polyorganosiloxane

compositions

The invention relates to a polyorganosiloxane composition, a method for combining the components and a method for vulcanizing said polyorganosiloxane compositions, the vulcanized composition obtainable thereby, composite materials which contain a substrate and said vulcanized composition, and the use of the polyorganosiloxane composition , The invention relates in particular to one-component silicone rubber mixtures which have a neutral crosslinking action at room temperature and which, after application and also after vulcanization, are compatible with paintable to paintable with conventional, solvent-based and water-based lacquers and also have a low volume loss.

Polyorganosiloxane compositions, hereinafter referred to as RTV-1K (room temperature-vulcanizing one-component) silicone rubber mixtures, are ready-to-use compositions that can be stored under the exclusion of moisture, and only react to form elastomers when atmospheric moisture is released to release decomposition products. Such polyorganosiloxane compositions have long been used for sealing joints in facade and window construction, in the sanitary and in the industrial sector. Some applications, especially indoors or in facade construction, require the application of paints to the silicone rubber compounds or to the elastomer created by vulcanization while at the same time specifying a small volume loss. Because of their widespread use, solvent-based and water-based paints are of particular importance. The latter have gained increasing interest in recent years, in particular, since volatile organic solvents can largely be dispensed with in the production of water-based paints. In general, silicone elastomers are considered incompatible with paint or even paintable, especially with water. This doctrine is represented in the patents US 4,902,575, US 4,906,707, US 4,965,311 and in US 5,063,270. There are application examples where the water-repellent character of silicone polymers is exploited. For example, silicone oils are used in the automotive industry for the production of polishing agents, the addition of which gives the polishing agents their water-repellent property (US Pat. No. 5,043,012). In U.S. 4,902,575, U.S. 4,906,707, U.S. 4,965,311 and U.S. 5,063,270, S. Yukimoto et al. Crosslinkable compositions based on MS polymers (“modified silicone”), the polymer skeletons of which are composed of polyethers (such as polyethylene oxide and polypropylene oxide). These crosslinkable mixtures are described by S. Yukimoto et al. as paintable with alkyd paints, via contact with Water-thinnable lacquers are not given here. Sealants based on MS polymers are not weather-resistant without the addition of antioxidants, but which can prevent the drying of air-drying oil-based lacquers, and their mechanical resilience properties are also not comparable with silicone elastomers. There was therefore a need , especially in the area of weather-resistant silicone rubber compounds, to search for paint-compatible or even paintable compositions.

Shimizu in US 4,358,558 presents a paintable polyorganosiloxane mixture which, in addition to an organoaminoxy compound as a crosslinker, contains low molecular weight reactive alpha-alkynols (C≡C triple bonds in addition to carbinol) as additional additives in smaller amounts. They are easily evaporable, sensitive to oxidation and easily decomposed with bases, so that their effectiveness is limited. In DE 3 025 376 (filing date: July 4, 1980) Sattlegger et al. overpaintable organopolysiloxane molding compounds with additions of short-chain paraffin hydrocarbons. However, this leads to a high volume loss of the resulting vulcanizate. Endres et al. in DE 3 836 916 (filing date: 10/17/89) paintable polydiorganosiloxane mixtures based on carboxylic acid amidoalkylalkoxy silicon compounds as crosslinkers,

Titanic acid ester and precipitated, hydrophobized chalk. Due to the high residual moisture of chalks, these RTV-1 K silicone rubber compounds are not particularly stable in storage. The teaching that in particular alpha, omega-trimethyl-terminated polydiorganosiloxanes disturb the ability to be painted and painted over with water-based paints is not mentioned here. O'Neil et al. describe in EP 0 618 257 neutral crosslinking organopolysiloxane compositions which can be painted over with different lacquers. The disadvantage of Schiller et al. used oxidatively crosslinking additives, so that EP 0 618 257 recommends mixing the sensitive additives only shortly before use (two-component system). Silicone rubber mixtures crosslinking at room temperature, comprising linear polyorganosiloxane, fillers, aminoalkylsilanes as adhesion promoters and silanes with hydrolyzable groups as crosslinking agents and optionally condensation catalysts have long been known and are described in patents EP 0 050 453, US 4,490,500, US 3,933,729, EP 000 929 and US 4,760 presented. However, none of these patents reveals indications of paint compatibility or even paintability. Schiller el al. in DE 3 808 200 present paintable or paintable one- or two-component compositions based on branched organosiloxane chains. The disadvantage of these systems is the more complex production of the branched-chain organosiloxanes and the high tensile stress / at 100% elongation from 0.45 to 0.75 N / mm ² (according to DIN 53504), which are disadvantageous for many applications as a joint seal.

It is considered state of the art that by selecting suitable residues of polydiorganosiloxane which are more polar than alkyl residues or by an increased proportion of branched polymers, ie polymers containing T or Q siloxane units, the paintability can also be influenced favorably. However, it is an object of this invention to achieve paintability with inexpensive, conventional raw materials or to use organosiloxanes whose organo residues R are inexpensive, resistant to oxidation and light

The use of alkyl aromatic compounds in silicone rubber mixtures is known and is described, for example, in DE 2 908 036 (filing date: 1.3.79). The alkyl aromatics serve here as an inexpensive, additional additive or as a replacement for the alpha, omega-trimethyl-terminated polydiorganosiloxanes otherwise used as plasticizers. Patent DE 4 415 396 (filing date: May 3, 1994) describes the use of alkyl aromatic compounds as plasticizers in particular in benzamide-crosslinking silicone rubber mixtures. However, none of these patents contain references to the paint compatibility or the paintability of these silicone rubber mixtures or the silicone elastomers resulting from vulcanization when the aromatic compounds described therein are used.

The object of this invention was to provide polyorganosiloxane compositions which, after direct application and also after vulcanization, can be coated or even coated with solvent-based or water-based paints, and which have the disadvantages of the RTV-1K compositions described in the prior art, such as lack of storage stability and high volume shrinkage of the vulcanizate through the use of e.g. larger quantities of short-chain, linear or cyclic hydrocarbons.

Surprisingly, the object described above is solved by providing a polyorganosiloxane composition, obtainable by a process which comprises the mixing and the reaction of the following components:

a) at least one crosslinkable polydiorganosiloxane, b) optionally a thickening or reinforcing filler c) at least one crosslinker selected from the group consisting of oxime silane

/ -siloxane crosslinkers and benzamidsilane / siloxane crosslinkers, d) at least one aminoalkylalkoxysiloxane as crosslinker or adhesion promoter, e) optionally an inert filler f) at least one organometallic catalyst g) optionally auxiliary substances customary for RTV1 K compositions and h) 1 to 18% by weight. -%, based on the total amount of the composition, alkyl aromatic compounds with an average molar mass, measured as weight average (M _w ) with the aid of gel permeation chromatography (GPC), from 200 to 500 g / mol in the respective compound class and one

Viscosity-density constant of at least 0.860.

The polyorganosiloxane compositions according to the invention preferably do not contain any a / p oma, omega-trimethyl-terminated polydiorganosiloxanes which are free of reactive groups in accordance with the definition of component a). The mixtures according to the invention with claimed amounts of the selected hydrocarbons allow paintability, but there is no major loss of volume. It was surprising that the replacement of the a / p .a, omega-trimethyl-terminated polydiorganosiloxanes usually used as plasticizers in silicone rubber mixtures by 1 to 18 wt .-%, based on 100 wt .-% of the composition, of an alkyl aromatic compound with a molecular weight from 200 to 500 g / mol and a VDK of at least 0.860 leads to polyorganosiloxane compositions which, after direct application, i.e. before crosslinking or vulcanization, as well as after vulcanization with solvent-based and water-based paints, are paint-compatible to paintable and also good Have paint adhesion. It was also surprising that this effect is only found in oxime and benzamide silane / siloxane crosslinking systems. In contrast to the state of the art it is possible to dispense with the use of oxidatively crosslinking additives that weaken the storage stability. It is also possible to dispense with the use of cyclohexane, isohexane, isooctane, isohexadecane, isododecane or isooctadecane as paraffin hydrocarbons, which cause a large volume loss of the corresponding vulcanizates, as well as branched polyorganosiloxane chains which are more difficult to produce. After application as well as after vulcanization, the RTV-1K silicone rubber mixtures according to the invention are notable for very good paint compatibility or paintability with solvent-based and water-based paints. The vulcanizates of the mixtures show a low volume loss (preferably less than about 8% by volume according to ISO 10563). The polyorganosiloxane compositions according to the invention are stable in storage in the absence of air.

The crosslinkable polyorganosiloxanes (component a) of the composition used according to the invention are preferably those of the general formula (I)

where R and R ² independently of one another are optionally substituted C ₁ -C ₁₀ -alkyl, C ₆ -C ₁₄ -aryl or C ₂ -C -o-alkenyl groups. R and R ² may be the same or different. In addition, R can also siloxane with the following groups D = R ² ₂ SiO, M = R ¹ ₃ - _a R ² a SiO _0, _5, T = R are ² SiO _3, _2, Q = _SiO4 / ₂ where preferably D groups should predominantly be present and the number of M groups depends on the number of D, T or Q groups and on the number of ≡Si-OR ² or ≡Si-OH groups. The content of Si-OR ² is 0.04-10 mol%, that for Si-OH 0.04-2 mol%. Preferred siloxane polymers are linear diorganosiloxanes with R = methyl, the degree of polymerization of which is known in the art Derive viscosity information lets, the non-uniformity M _w / M _n (weight / number average) should not be greater than 30. The polyorganosiloxanes can also be present as a mixture. Larger proportions of low molecular weight, non-crosslinkable siloxanes impair paintability. With increasing chain length, siloxane polymers with T or Q units are less and less easy to prepare as flowable polymers. Therefore, the proportion of these units with chain lengths of n> 500 is preferably limited to less than 1% by weight. In the case of low molecular weight siloxane polymers, very high proportions (up to approx. 45% by weight) of Q or T units can occur in still free-flowing polymers. In the event that such reactive polymers according to a) are mixed into the predominantly linear diorganosiloxane polymers, the proportion of these polymers, which then additionally contain T or Q units with> 1% by weight, should preferably be in proportions of less than 30% by weight. % in component a) may be limited.

The above-mentioned radicals R ² include optionally substituted C1-C1 ₀ -

Alkyl groups include linear and branched alkyl groups having 1 to 10 carbon atoms: for example methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl etc. Preferred are methyl and ethyl groups. Substituents of the above-mentioned optionally substituted C ₁ -C ₁₀ alkyl groups R ² in particular also include fluorine. Examples of the substituted alkyl groups are trifluoropropyl radicals, C ₆ Fι ₃ -CH ₂ CH ₂ -, C ₃ F ₅ -O- CH ₂ CH ₂ CH ₂ - or fluorooxirane propyloxypropyl. The optionally substituted C ₆ -C ₄ aryl groups mentioned under R above include aromatic groups with 6 to 14 carbon atoms, such as, for example, phenyl or naphthyl, etc. Phenyl is preferred.

The above-mentioned optionally substituted C ₂ -C aloyl groups include linear or branched alkenyl groups having 2 to 10 carbon atoms: for example vinyl, allyl, hexenyl, octenyl, norbomenyl or limonyl etc. Vinyl is preferred. The substituents R ¹ are each independently of one another -OH or hydrolyzable groups, ie groups which react with water to form HO-Si groups, preferably oxime groups (-0-N = CR ⁵ ₂ ) and benzamide groups (-N ( R ² ) -C (= O) R ⁵ ) and alkoxy groups (-OR ² ), wherein R ^{2 is in} each case as defined above. The degree of polymerization ^' n ^' is an integer and can preferably assume values from 50 to 2500, ie for R = methyl 50 mPa.s to 800 Pa.s at 25 ° CD = 1 sec ^_1 , while a = 0, 1 or 2 is.

The crosslinkable polyorganosiloxanes used according to the invention can optionally be used in a separate working step or in situ in the preparation of the polyorganosiloxane composition according to the invention, for example by mixing an a / pfta, omeo; a-hydroxyI-terminated polyorganosiloxane with at least two equivalents of an oxime silane / siloxane crosslinker or benzamide -silane / siloxane crosslinking as component c) and their implementation at 0-100 ° C.

Furthermore, crosslinkable polyorganosiloxanes a) used according to the invention can also be obtained by reacting an alpha, omega-hydroxy-terminated polyorganosiloxane with at least two equivalents of an aminoalkylalkoxysilane or siloxane (component d).

The amount of component a) in the polyorganosiloxane compositions according to the invention is preferably from 22 to 98.79% by weight, based on the total mass of the composition a) to h).

The fillers, component b), include, for example, amorphous or crystalline, reinforcing hydrophobic or hydrophilic silicas with BET surface areas of 30 to 400 m ² / g (Aerosil 130, 150, 200, R972, 974, HDK H20). These are reinforcing and thickening fillers. They allow the strength of the crosslinked rubber to be increased and the thickening and stability of the non-crosslinked siloxane composition to be adjusted. Are preferred

BESTATIGUNGSKOPIE this is hydrophobic silicas with BET surface areas of 90-200 m ² / g in amounts of 0-15% by weight, preferably 1-7% by weight. The term hydrophobic includes all types of hydrophobization, such as those with silanes, siloxanes or d-C ₃ o-fatty acid or fatty alcohol-fatty acid-alcohol ester or fatty acid amide derivatives and CrC ₃ o-phosphoric acid esters.

The oximosilane / siloxane crosslinkers or benzamidosilane / siloxane crosslinkers (component c)) used according to the invention are preferably an organosilicon compound which has at least two groups Si-ON = CR ⁵ ₂ and / or Si-N (R ² ) - C (= O) R ⁵ , especially around

Organosilicon compound of formula (II)

where the substituents R ⁴ = R ² and each independently 'optionally substituted CrC ₁₀ alkyl, C ₆ -C aryl or C ₂ -C ₀ alkenyl groups and the substituents R ^{3 are} hydrolyzable groups, with the proviso that the at least two R ³ radicals represent an oxime group (-ON = CR ⁵ ₂ ) and / or benzamide group (-N (R ² ) -C (= 0) R ⁵ ). The index b is an integer and can have the values 0, 1 or 2, where the substituent R ^{4 has} the meaning described above, and if there are several substituents R ⁴ , these may be the same or different. In the event that at least one substituent R ^{3 is} a benzamide group (-N (R ² ) -C (= O) R ⁵ ), R ^{3 can} in particular also represent an alkoxy group (-OR ² ). The hydrolyzable, reactive groups can be present both in a molecule and in an oligomeric or polymeric siloxane. Such siloxanes are preferably condensation products.

Condensation products of these crosslinkers are formed, for example, by adding water, siloxane diols or silanols (SiOH-functionalized linear or branched polysiloxanes) with catalysis with themselves or different crosslinkers with one another (component c), the oximosilane / siloxane crosslinkers, the benzamidosilane / siloxane crosslinker or the aminoalkylalkoxysilanes / siloxanes (component d)) which are used in the composition according to the invention.

In this condensation, alcohols, hydroxylamines or benzamides are released as the reaction product.

The oximosilane / siloxane crosslinkers (component c)) are particularly preferably tris (methylethylketoximo) vinylsilane and methyltris (methylethylketoximo) silane.

The benzamidosilane / siloxane crosslinking agents are particularly preferably bis (N-methylbenzamido) ethoxymethyl silane.

The amount of the oximosilane / siloxane crosslinking agent or benzamidosilane / siloxane crosslinking agent used in the composition according to the invention is preferably at least about 1.0% by weight, more preferably at least about 2.0% by weight. The maximum is about 30% by weight, preferably about 10% by weight, so that the following preferred ranges result: from 1.0% by weight to 30% by weight, more preferably from 2.0% by weight up to 10% by weight, based in each case on the total amount of the composition according to the invention.

The aminoalkylalkoxysilanes / siloxanes (component d) used according to the invention are preferably those of the general formulas (III) and (IV)

X- (CH ₂ ) _c -Si (OR ⁶ ) ₃ X- (CH ₂ ) _c -Si (OR ⁶ ) ₂ -O [Me ₂ SiO] _n Si (OR ⁶ ) ₂ - (CH ₂ ) _c - X

(III) (IV) where X is selected from -NH ₂ , -NHR ⁶ , -NR ⁶ ₂ -NHCH ₂ CH ₂ NH ₂ , and the

Substituents R ⁶ each independently represent optionally substituted linear or cyclic C 1 -C 8 -alkyl, C ₆ -Ci ₄ aryl, C ₂ -C 1 -C alkenyl or siloxane groups. The index c is an integer and can preferably be values assume between 2 and 10, most preferably c is 3. The values for n are between 1-50, preferably 4-7. Aminoalkylalkoxysiloxanes in the above formula, in which R ^{5 represents} a siloxane group, are obtained, for example, by condensation of the compounds mentioned with themselves in the presence of water or siloxane diols or SiOH-functionalized linear or branched polysiloxanes, silanols and catalyst with the escape of alcohol.

Mixtures of aminoalkylalkoxysilane / siloxanes can also be used.

Aminopropyltrialkoxysilanes and alpha, omega- (diethoxy-3-propylamine) -terminated polydimethoxysiloxanes are particularly preferred, and aminopropyltrimethoxysilane, aminopropyltriethoxysilane and a / p / .a, omega- (diethoxy-3-propyloxane) -terminated daminas are very particularly preferred.

The amount of the aminoalkylsiloxanes d) used according to the invention in the composition according to the invention is preferably at least about 0.1% by weight, more preferably at least about 0.2% by weight. The maximum amount is about 30% by weight, preferably about 20% by weight, so that the following preferred ranges result: from 0.1% by weight to 30% by weight, more preferably from 0.2% by weight up to 20 wt .-%, each based on the total amount of the composition according to the invention a) <- h).

The inert filler or inert filler of component e) comprises the non-reinforcing or thickening silicates, oxides, carbonates or silicas. The surfaces are 0.3 - 30 m ² / g according to BET, preferably 1-iθ m ² / g according to BET, the maximum particle size is at most 100 μm. They are used in amounts of 0-65% by weight, based on components a) to h), preferably 0-40% by weight. The fillers are also preferably hydrophobic, ie with silanes, siloxanes, silazanes or in particular surface-treated for chalks with C ₃₀ -C fatty acid or fatty alcohol fatty acid alcohol ester or fatty acid amide derivatives, preferably stearic acid, or C ₃₀ phosphoric acid esters.

The catalysts of component f) include, for example: organotin compounds, organotitanium compounds, organozirconium compounds. Preferred organotin compounds are dioctyltin oxide, dibutyltin oxide, dimethyltin oxide, dimethyltin dichloride, dibutyltin dichloride, tributyltin chloride, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin maleate, dibutyltin dihexanoate, dibutyltin dioctoate, Dioctylzinndioctoat, dioctyltin dilaurate, dioctyl zinnbutoxystannan and / or Tributylethoxystannan. Furthermore, reaction products of the organotin compounds described above with one or more optionally substituted silicic acid esters, polysilicic acid esters, organylalkoxysilanes and / or their partial hydrolyzates can be used as catalysts containing tin.

Chelates of calcium and zinc can also be used. Preferred organotitanium compounds are titanium chelate catalysts. These are known per se and are described, for example, in US 4,680,364, US 3,689,454, US 3,334,067, DE 19507416 and US 4,438,039. The amount of catalyst f) in the compositions according to the invention is preferably 0.01 to 5% by weight, based in each case on the total mass of the composition a) to h) according to the invention.

Dialkyltin carboxyxlates are preferred, particularly preferably dialkyltin carboxylates with polysilicic acid esters, or dibutyltin oxide and aminopropyltrimethoxysilane or titanium chelates, preferably such as bis (1,3-propanedioxy) titanium (IV) acetylacetonate-ethyl acetoacetate.

The alkyl aromatic compounds used according to the invention

(Component h) with an average molecular weight of 200 to 500 g / mol include individual compounds or mixtures (including isomer mixtures) of optionally substituted alkylbenzenes, alkylnaphthenes, alkylanthracenes, Alkylnaphthacenes, alkylindens, alkylfluorenes. The aromatic compounds can be substituted one or more times with alkyl groups. The alkyl groups themselves can be linear or branched. Pure substances or mixtures (including mixtures of isomers) of alkylbenzenes are preferred.

As component h), the alkylaromatic compounds preferably have a viscosity-density constant (VDK) of at least about 0.860. The viscosity-density constants (VDK) of the alkylaromatic compounds are determined from the aniline points according to the following equation (Handbuch der Gummi- industriθ, 2nd edition, Bayer AG, business area rubber, Leverkusen, 1991) from the aniline points: VDK = (1196 - aniline point in ° F) / 1170

The aniline points themselves are determined in accordance with ASTM D 611. Preferred alkylaromatic compounds are mixtures of isomers of linear and branched monoalkylbenzenes, mixtures of isomers of largely linear dialkylbenzenes or mixtures of isomers of branched-chain mono- and di- and trialkylbenzenes, etc. For the alkylaromatics according to the invention it is not sufficient to select them only according to the molecular weights, but one must be used at the same time Make a selection based on the VDK criterion in order to obtain paintable to paint-compatible materials that also have a low volume loss.

The alkyl aromatic compounds used according to the invention with an average molecular weight of 200 to 500 g / mol (component h) are contained in the composition according to the invention in an amount of 1 to 18% by weight, preferably 2 to 15, based on the total amount of the composition. The molecular weight was determined as the weight average M _w using gel chromatography (GPC).

In addition to the above-mentioned essential components a) to f), the polyorganosiloxane compositions according to the invention may contain, as component g), further auxiliaries customary for one-component room temperature vulcanizable polyorganosiloxane composition (RTV-1 K). These auxiliaries include, for example, thickeners or stabilizers e.g. Phosphoric acid esters, complexing agents, antioxidants, adhesives, such as organofunctional alkoxysilanes / siloxanes, reversion or hot air stabilizers (such as chelates, salts or oxides of Ti, Fe or Ce), fungicides, inorganic or organic dyes or dye pigments or conductive powders, glass balls or Fibers such as carbon black, metallized mineral powder, metal or graphite bevels.

The polyorganosiloxane compositions according to the invention thus preferably consist of mixing and reaction of the components:

22 to 98.79% by weight of polymer of component a) 0 to 15% by weight of thickener as component b) 0.1 to 30% by weight of crosslinking agent as component c) 0.1 to 30% by weight of adhesive or crosslinker as component d) 0 to 65% by weight of inert filler as component e) 0.01 to 5% by weight of catalyst as component f)

0 to 20% by weight of auxiliaries as component g),

1 to 18% by weight of the alkylbenzenes according to the invention as component h),

where the amounts are based on the total amount of the polyorganosiloxane compositions a) - h).

The polyorganosiloxane compositions according to the invention are expediently obtained by mixing and reacting the essential components mentioned a) to h) and the other components which may be present. The above-mentioned components a) to h) of the composition of the invention can advantageously be combined at temperatures of 20-90 ° C. by first mixing components a) and c) optionally d), allowing them to react and then the other components added there. The crosslinkable polydiorganosiloxanes (component a) used according to the invention can optionally be used in a separate working step or in situ in the preparation of the polyorganosiloxane composition according to the invention, for example by reacting an alpha, omega-hydroxyl-terminated polyorganosiloxane with at least two equivalents of an oximosilane / siloxane crosslinker or benzamidosilane / siloxane crosslinker (component c) can be produced. Furthermore, crosslinkable polyorganosiloxanes a) used according to the invention can also be obtained by reacting an alpha, omeα / a-hydroxyl-terminated polyorganosiloxane with at least two equivalents of an aminoalkylalkoxysilane / siloxane (component d). A sequence in which an alpha, omega-hydroxy-terminated polyorganosiloxane is presented together with component c) or d) is therefore preferred. The automatic reaction with one embodiment of component a), the a / p / .a, omeo; a-hydroxyl-terminated polyorganosiloxane in the form of the starting material, leads to the inventive reaction product of component a) generated in situ. If different components c) and d) are used, component c) or d) which reacts faster with the a / pfta, omega-hydroxyl-terminated polyorganosiloxane to give the reaction product of component a) is particularly preferably added first. Only then is it particularly preferred to add all the other components such as b) to h). The order of addition of the further components b) or e) to h) has no influence on the effect of paintability or paint compatibility according to the invention.

The polyorganosilane compositions or RTV-1 K compositions according to the invention can be carried out stepwise in a batch process or continuously with the aid of Extruders are manufactured. Depending on the application, the compositions according to the invention can be adjusted to be stable or flowable by mixing with exclusion of moisture and inerting with, for example, nitrogen in machines customary for RTV 1 K, such as extruders, pilgrim step mixers (Buss co-kneaders), kneaders or, for example, planetary mixers at 20 mixes up to 90 ° C under a nitrogen atmosphere with exclusion of moisture and uses the thickeners in particular b) according to the prior art in a suitable manner.

The polyorganosiloxane compositions according to the invention are particularly suitable for the production of one-component polyorganosiloxane compositions vulcanizable at room temperature. The polyorganosiloxane compositions vulcanized after moisture ingress have elastomeric properties. The vulcanized polyorganosiloxane compositions are produced by allowing the polyorganosiloxane compositions to come into contact with moisture in the ambient air at 0 to 120 ° C., preferably 0 to 100 ° C.

The polyorganosiloxane compositions according to the invention are particularly suitable for the production of sealants, adhesives, moldings, profiles. Coatings or molded-in-place seals that are paint-compatible to paintable both in the non-cross-linked and in the cross-linked state.

The vulcanized polyorganosiloxane compositions according to the invention serve, for example, as sealants or adhesives or coatings for joints, the combination of glass with mineral substrates, wood or thermoplastics, profiled, shaped seals, ^' molded in place seals ^' or the coating of roofs or tissues.

Accordingly, the invention relates to uncured and cured (crosslinked, vulcanized) adhesives, joint seals, moldings, profiles, or Formed-in-place seals (gaskets) or coatings, the surface of which at least partially has a lacquer coating.

According to the invention, paint compatibility is understood in the wording of the DIN 52452 standard to mean the material property of a movement-compensating sealant, which permits a technically and optically flawless overlapping limitation of a maximum of 2 mm with a paint on the sealant in a joint, without damaging interactions between the sealant, the Paint and / or the adjacent components result.

On the other hand, the term paintability in the sense of the invention encompasses the material property of being able to apply one or more coats of paint to a movement-compensating sealant without there being any harmful interactions of a functional or optical nature, the following requirements preferably being met:

1.) Defect-free coating of the sealant surface, i.e. no wetting disruption, 2.) perfect drying of the paint, 3.) no color change of the paint, 4.) elasticity according to the permissible total deformation of the paint

Sealant, without cracking in the paint and good paint adhesion. 5.) In addition, according to the invention, a small volume loss (<8% by volume) is required.

The layer thicknesses of the paints or paints on the elastomeric polyorganosiloxane compositions are usually from 1 μm to 1000 μm. In general, lacquers are liquid, pasty or powder-like coating materials that, when applied to a substrate, provide a covering coating with protective, decorative or specifically technical properties (DIN 971-1 (September 1996)).

Conventional, solvent-based paints include all paints that contain natural (ie vegetable or animal origin) or synthetic solvents. Typical and more widespread representatives of solvent-based paints are alkyd resin paints, which according to DIN 55945 (August 1983) are paints that contain alkyd resins as characteristic film formers. The DIN 53183 (September 1973) standard defines alkyd resins as polyester resins modified with natural fats and oils and / or synthetic fatty acids, which are produced by esterification of polyhydric alcohols, at least one of which must be trihydric, with polybasic carboxylic acids. For example, alkyd resins can be esterified by di- and polyfunctional alcohols (e.g. ethylene glycol, 1, 2-propylene glycol, glycerol, trimethylolpropane, pentaerythritol and dipentaerythritol) with dicarboxylic acids (e.g. phthalic, isophthalic, terephthalic, maleic, adipic and dimer fatty acids) or their anhydrides and saturated or unsaturated fatty acids are produced, see also Ullmann ^'s Encyclopedia of Industrial Chemistry 6th Ed. 2001, Electronic Release keyword ^' Alkyd ^*' etc.. Alkyd resin varnishes vary widely in their solvent content and, depending on the curing mechanism, include air-drying (oxidative crosslinking via olefinic double bonds, eg paintwork) and thermosetting lacquers (crosslinking via condensation reactions, eg stoving lacquers).

Water-based or water-dilutable paints are described in DIN 55945 (September 1996), they can still contain small amounts of organic solvents. They include e.g. the acrylic latex emulsion paints that can be used for painting.

Examples:

The following examples serve to illustrate, but without being limiting. The polyorganosiloxanes were prepared in the order given below in 1 liter planetary mixers (from Drais) or 20 liter planetary dissolvers (from Linden), in accordance with the examples given below. The individual constituents were mixed at intervals of 5 min (unless otherwise stated) at temperatures between 25-60 ° C. under dried nitrogen. After production was complete, trapped gas bubbles were removed from the mixture by stirring under a slight vacuum. The polyorganosiloxane masses were then filled into airtightly sealable plastic cartridges in order to make them available for the comparative studies.

For example:

A silicone rubber mixture is produced in accordance with the following formulation.

1) 44.5 parts by weight of a linear a / pΛa, omega-hydroxyl-terminated poly-dimethylsiloxane, which is characterized by a viscosity of 80 Pa s at 25 ° C (shear rate gradient D = 1 s ^{~ 1} ).

2) 10.0 parts by weight of a mixture of monoalkylbenzenes as component h) with a density of 0.87 g / ml at 15 ° C, a kinematic viscosity of 58 mm ² / s at 40 ° C, an initial boiling point of 335 ° C, an average molecular weight of 350 g / mol, an aniline point of 68 ° C and a VDK of 0.890, which was obtained under the trade name "Progyline 150 B" from Shrieve Products International Ltd. 3) 0.5 Parts by weight of tris (methylethylketoximo) vinylsilane (then 10 min mixing time) as component c),

4) 4.0 parts by weight of methyl-tris (methylethylketoximo) silane as component c)

5) 35.0 parts by weight of ground chalk (CaCO ₃ ), which was surface-treated with stearic acid and used as component e) 6) 4.5 parts by weight of hydrophilic silica as component b), which was obtained from Degussa under the name Aerosil® 150,

7) 1.5 parts by weight from a mixture consisting of 0.5 parts by weight of N- (2-aminoethyl) -3-aminopropyltrimethoxysilane and 1.0 part by weight of an a / pfra, omega-bis ( diethoxy-3-propylamine) -terminated dodecamethylhexasiloxane, which was used as component d),

8) 0.1 part by weight resulted from a reaction of 83.8 parts by weight of dibutyltin oxide and 116.2 parts by weight of aminopropyltrimethoxysilane as component f).

The silicone rubber mixture produced in this way is homogeneous, supple, soft and stable (Boeing flow test: 0 mm). Further typical properties of this paste or of the elastomer obtained by vulcanization are summarized in Table 1. The RTV-1 K compound shows very good adhesion to PVC substrates. To check the storage stability, samples of this formulation are filled into aluminum tubes, sealed airtight and stored at 70 ° C. in order to be able to assess the cross-linkability that can be measured after accelerated aging as storage stability. After 20 weeks of storage at 70 ° C., the tubes are cooled to room temperature and 2 mm thick test plates are made from the sealing compound. The rubber-mechanical data were evaluated in accordance with DIN 52455 on the glass test specimen. The paste shows normal hardening behavior in a standard climate (room temperature 25 ° C, 50% relative air humidity).

Table 1: Properties of the RTV-1 K composition according to the formulation from Example 1

Properties Results from Example 1

) ^* CF = cohesive failure regarding adhesive layer

The paint adhesion is checked according to ASTM (American Society for Testing and Materials) D-3359-78 by allowing the test paints on the sealant test panels to dry completely for a period of 2 weeks, the paint surface with a blade in square boxes (2, 5 mm edge length), then cover the cut lacquer surface with adhesive tape and quickly peel it off at a 180 ° angle. Without exception, all the paints tested adhere very well (100%) to the silicone vulcanizate according to the invention. The volume loss determined according to ISO 10563 (4 weeks storage in a standard climate, then 7 days at 70 ° C and finally 1 day in the standard climate) is only 6.1%.

The results of the paint compatibility and paintability tests are shown in Table 3 below.

Example 2:

A silicone rubber mixture is produced according to Example 1, but in which instead of 10.0 parts by weight of a mixture of monoalkylbenzenes with a density of 0.87 g / ml at 15 ° C. and a kinematic viscosity of 58 mm ² / s at 40 ° C, a boiling point of 335 ° C and an average molecular weight of 350 g / mol 10.0 parts by weight of a mixture of different isomers of largely linear dialkylbenzenes with a density of 0.87 g / ml at 25 ° C, one kinematic viscosity of 17.9 mm ² / s at 40 ° C, an initial boiling point of 330 ° C, an average molecular weight of 330 g / mol, an aniline point of 52.5 ° C and a VDK of 0.914, which is used under the Trade name "Alchisor 3 SP" was obtained from Sasol Italy SpA.

The silicone rubber mixture produced in this way is homogeneous, supple, soft and stable (Boeing flow test: 0 mm). When testing the paint compatibility or paintability, a very good paint flow (see Table 3) and a very good paint adhesion according to ASTM D-3359-78 was determined, because all the paints tested adhere very well (100%) to the silicone vulcanizate without exception. Further properties of the silicone elastomer:

Tensile stress at 100% elongation: 0.43 N / mm ² , tensile strength: 0.43 N / mm ² , elongation at break 106%, Shore A hardness: 34 °, volume shrinkage (ISO 10563): 6.0%,

Mass shrinkage (storage at 120 ° C, 24 hours): 5.9% Example 3:

A silicone rubber mixture is produced according to Example 1, but in which instead of 10.0 parts by weight of a mixture of monoalkylbenzenes with a density of 0.87 g / ml at 15 ° C. and a kinematic viscosity of 58 mm ² / s at 40 ° C, a boiling point of 335 ° C and an average molecular weight of 350 g / mol 10.0 parts by weight of a mixture of different isomers of branched chain mono- and polyalkylbenzenes with a density of 0.87 g / ml at 15 ° C , a kinematic viscosity of 40 - 48 cSt at 40 ° C, a boiling point of 330 ° C, an average molecular weight of 365 g / mol, an aniline point of 64 - 66 ° C and a VDK of 0.893 - 0.896, which is used under the trade name "HAL 47" was obtained from the company Janex SA.

The silicone rubber mixture produced in this way is homogeneous, supple, soft and stable (Boeing flow test: 0 mm). When testing the paint compatibility or paintability, a very good paint flow (see Table 3) and a very good paint adhesion according to ASTM D-3359-78 was determined, because all the paints tested adhere very well (100%) to the silicone vulcanizate without exception. Further properties of the silicone elastomer: tensile strength: 0.40 N / mm ² ,

Shore A hardness: 32,

Volume shrinkage (ISO 10563): 7.5%, mass shrinkage (storage at 120 ° C, 24 hours): 4.9%

Example 4:

According to Example 1, a silicone rubber mixture is produced, but in which instead of 10.0 parts by weight of a mixture of monoalkylbenzenes with a density of 0.87 g / ml at 15 ° C., a kinematic viscosity of 58 mm ² / s

40 ° C, a boiling point of 335 ° C and an average Molecular weight of 350 g / mol 10.0 parts by weight of a mixture of 70% long-chain alkylbenzenes and 30% linear and branched paraffins (-C ₄ H ₃ o to C ₂₆ H ₅₄ ), in total with a density of 0.84 g / ml at 15 ° C, a kinematic viscosity of 12 mm / s at 40 ° C, a boiling point of about 270 ° C, an aniline point of 76 ° C and a VDK of 0.878, which is sold under the trade name "SHR 105" by was obtained from Shrieve Products International Ltd.

The silicone rubber mixture produced in this way is homogeneous, supple, soft and stable (Boeing flow test: 0 mm). When testing the paint compatibility or paintability, a very good paint flow (see Table 3) and a very good paint adhesion according to ASTM D-3359-78 was determined, because all the paints tested adhere very well (100%) to the silicone vulcanizate without exception. Further properties of the silicone elastomer: tensile strength: 0.39 N / mm ² ,

Shore A hardness: 34,

Volume shrinkage (ISO 10563): 11.2%, mass shrinkage (storage at 120 ° C., 24 hours): 7.2% Due to the 30 percent paraffins content in the hydrocarbon mixture used, the volume shrinkage compared to the values found in Examples 1 to 3 slightly increased.

Example 5, comparison:

A silicone rubber mixture is produced according to Example 1, but in which instead of 10.0 parts by weight of a mixture of monoalkylbenzenes with a density of 0.87 g / ml at 15 ° C. and a kinematic viscosity of 58 mm ² / s at 40 ° C, a boiling point of 335 ° C and an average molecular weight of 350 g / mol 10.0 parts by weight of a mixture of linear and branched chain paraffins (Cι ₂ H ₂₆ to C ₂₆ H ₅₄ ), with a density of 0, 78 g / ml at 15 ° C, a kinematic viscosity of 5.1 cSt at 20 ° C, an initial boiling point of 250 ° C and an average molecular weight of 212 g / mol, an aniline point of 95 ° C and a VDK of 0.852 (which is outside the claimed range), which was obtained under the trade name "Alchisor S" from Sasol Italy SpA. The silicone rubber mixture thus produced is homogeneous , supple, soft and stable (Boeing flow test: 0 mm). When testing the paint compatibility or paintability with water-based paints, a satisfactory result is not achieved (see Table 3). The volume loss of 21.8% determined according to ISO 10563 is compared to the values found in Examples 1 to 3. Significantly increased properties of the silicone elastomer:

Tensile strength: 0.41 N / mm ² ,

Elongation at break 77%,

Shore A hardness: 34,

Mass shrinkage (storage at 120 ° C, 24 hours): 14.0%, volume shrinkage (ISO 10563): 21.8%

Example 6, comparison:

A silicone rubber mixture is produced according to Example 1, but in which instead of 10.0 parts by weight of a mixture of monoalkylbenzenes with a density of 0.87 g / ml at 15 ° C. and a kinematic viscosity of 58 mm ² / s at 40 ° C, a boiling point of 335 ° C and an average molecular weight of 350 g / mol 10.0 parts by weight of an a / p7a, o /? 7ega-trimethyl-terminated polydimethylsiloxane, which is characterized by a viscosity of 100 mPa-s at 25 ° C (shear rate gradient D = 1 s ^"1 ) is used.

The silicone rubber mixture produced in this way is homogeneous, supple, soft and stable (Boeing flow test: 0 mm). When testing the paint compatibility or paintability with water-based paints a satisfactory result is not achieved, even the course of the solvent-based paints is worse (see Table 3). Further properties of the silicone elastomer:

Tensile stress at 100% elongation: 0.40 N / mm ² , tensile strength: 0.41 N / mm ² ,

Elongation at break 110%,

Shore A hardness: 32,

Volume shrinkage (ISO 10563): 5.9%

Test results:

To test the paint compatibility or paintability of the polyorganosiloxane compositions prepared in Examples and Comparative Examples 1 to 5, a 2 mm thick sealant test plate was pulled out and cured in a climatic room (room temperature, 50% relative atmospheric humidity). After a day (24 hours) or after 7 days, a series of eight commercially available oil and water-based paints was applied to the fur:

1.) water-based paint "Aquawood DSC colorless E-statics", colorless, from Adlerwerk, Lackfabrik, A-6130 Schwaz

2.) water-based acrylic wood glaze, walnut, water-dilutable, from

Glasurit GmbH, 48138 Münster 3.) water-based paint "Sigma S2U nova satin", white, from Sigma Coatings, 1422 AD Uithoorn, Holland 4.) water-based paint "Sigma S2U nova satin", blue, from Sigma

Coatings, 1422 AD Uithoorn, Holland 5.) water-based acrylic lacquer "Permacryl", black, glossy, microporous, from Trimetal Paints, 6222 AA Mastricht, Netherlands 6.) water-based acrylic lacquer "colored acrylic", gentian blue, water-dilutable, from OBI Systemzentrale, 42929 Wermelskirchen 7.) solvent-based, oil-based alkyd resin lacquer "Sigma schakelverf", white, from Sigma Caotings, 1422 AD Uithoorn 8.) solvent-based, oil-based lacquer, "Seiden-Herbol®, Herbosatin", silk gray, from Akzo Nobel Deco GmbH, 50827 Cologne

After a drying time of about 12 hours, the paint flow on the test plate, the sealant skin, is assessed according to the following criteria:

Tab. 2: Assessment criteria for the paint flow

With all of the oil- and water-based paints used, complete wetting of the sealant surfaces was observed in the polyorganosiloxane compositions according to the invention (see Table 3), the vulcanization time (1 or 7 days) having no effect on the course of the paint. In all cases, the paints applied to the vulcanizate dried within a period of max. Flawlessly through for 2 hours, did not discolor and showed no wrinkles on the lacquer surface, ie ^' wrinkle ^' formation. In contrast, comparative examples 5 and 6 did not show any coherent paint surface or crack formation in the vast majority of paints.

Table 3: Compilation of the paint courses

Example 7, comparison:

A silicone rubber mixture is produced according to Example 1, but in which instead of 10.0 parts by weight of a mixture of monoalkylbenzenes with a density of 0.87 g / ml at 15 ° C. and a kinematic viscosity of 58 mm ² / s at 40 ° C, a boiling point of 335 ° C and an average molecular weight of 350 g / mol 10.0 parts by weight of a mixture of branched chain monoalkylbenzenes with a density of 0.87 g / ml at 15 ° C, a kinematic viscosity of 380 cSt at 40 ° C, a boiling point of 295 ° C, an average molecular weight of 600 g / mol (not according to the invention), an aniline point of 103.0 ° C and a VDK of 0.836 (outside the claimed range of the invention), which is used under the trade name "HAL 39" was obtained from the company Janex SA. On a 2 mm thick sealant test plate vulcanized in a standard climate (room temperature, 50% relative humidity), a strong exudation behavior of the monoalkylbenzenes used is observed immediately after the test plate has been produced, so this silicone rubber mixture is not suitable for use as a sealant in the sense of the invention, which should also have a small volume loss.

Example 8:

According to Example 1, silicone rubber mixtures are produced which, however, instead of 10.0 parts by weight, 5.0 parts by weight (formulation 8 A), 15.0 parts by weight (formulation 8 B), or 20 parts by weight. Parts (formulation 8 C) of a mixture of monoalkylbenzenes with a density of 0.87 g / ml at 15 ° C, a kinematic viscosity of 58 mm ² / s at 40 ° C, a boiling point of 335 ° C, an average molecular weight of Contain 350 g / mol, an aniline point of 68 ° C and a VDK of 0.890, which was obtained under the trade name "Progyline 150 B" from Shrieve Products International Ltd. All silicone rubber mixtures produced in this way are homogeneous, smooth and soft. While the RTV-1 K masses of formulations A and B are stable (both Boeing flow tests: 0 mm), formulation C leads to an easily flowable mass (Boeing flow test: 5 mm) The vulcanizates of the Mischu show paintability ngen, containing 5 to 15 parts by weight of alkylbenzenes, good to very good paint progressions (see Table 4), only a water-based acrylic paint (paint no. 5) shows the vulcanizate of the mixture containing 15 parts by weight of the described alkylbenzene , only 80 percent wetting. Table 4: Compilation of the paint courses

Formulation A: tensile strength: 0.42 N / mm ² , elongation at break 80%, Shore A hardness: 36 °, volume shrinkage (ISO 10563): 6.9%

Formulation B: tensile stress at 100% elongation: 0.29 N / mm ² , tensile strength: 0.31 N / mm ² , elongation at break 150%, Shore A hardness: 25,

Volume shrinkage (ISO 10563): 6.3% Formulation C: tensile stress at 100% elongation: 0.24 N / mm ² ,

Tensile strength: 0.29 N / mm ² ,

Elongation at break 220%,

Shore A hardness: 21.

Volume loss (ISO 10563): 5.6% measured on a 2 mm thick sealant test plate vulcanized in a standard atmosphere (room temperature, 50% relative air humidity), the monoalkylbenzenes used are exudated after about a day, so this silicone rubber mixture is not suitable for Use as a sealant.

Example 9, comparison:

According to Example 1, a silicone rubber mixture is prepared, but instead of 1.5 parts by weight of a mixture consisting of 0.5 parts by weight of N- (2-aminoethyl) -3-aminopropyltrimethoxysilane and 1.0 part by weight. Parts of an alpha, omega-bis (diethoxy-3-propylamine) -terminated dodecamethylhexasiloxane (both as component d), 1.5 parts by weight of tris [3- (trimethoxysilyl) propyl] isocyanurate as component d) is used.

The silicone rubber mixture produced in this way is homogeneous, supple, soft and stable (Boeing flow test: 0 mm). A satisfactory result is not achieved when testing the paint compatibility or paintability with water-based paints (see Table 5). Further properties of the silicone elastomer:

Tensile strength: 0.44 N / mm ² , elongation at break 90%, Shore A hardness: 36,

Volume loss (ISO 10563): 6.1% Table 5: Compilation of the paint courses

Example 10 A and B, comparison:

As a comparison, silicone rubber mixtures are produced with the replacement of component c) on the basis of other ^' neutral ^' (ie non-acid-forming) alkoxy crosslinking agents (formulation A) and on the basis of acid-forming acetate crosslinking agents (formulation B) in accordance with the following formulations, which also contain monoalkylbenzenes.

Formulation 10A:

1) 45.0 parts by weight of an a / pfta, omeG / a-hydroxyl-terminated

Polydimethylsiloxane, which is characterized by a viscosity of 80 Pa s 25 ° C (shear rate gradient D = 1 s ^"1 ) (component a)).

2) 10.0 parts by weight of a mixture of monoalkylbenzenes with a density of 0.87 g / ml at 15 ° C, a kinematic viscosity of 58 mm ² / s at 40 ° C, a boiling point of 335 ° C and one average

Molecular weight of 350 g / mol, which was obtained under the trade name "Progyline 150 B" from Shrieve Products International Ltd. (component h).

3) 1.5 parts by weight of a mixture of mono- and bis (2-ethylhexyl) phosphoric acid ester (stabilizer as component g))

4) 45.0 parts by weight of precipitated chalk (CaCO ₃ ), which was surface-treated with stearic acid (component e))

5) 3.0 parts by weight of methyltrimethoxysilane (component c), not according to the invention)) 6) 0.5 parts by weight of methanol (component g))

7) 1.0 part by weight of bis (1,3-propanedioxy) -titanium (IV) -acetylacetonate-ethylaceto-acetate (component f))

8) 3.0 parts by weight of N- (2-aminoethyl) -3-aminopropyltrimethoxysilane (component d)

Formulation 10 B:

1) 86.0 parts by weight of a linear alpha, omega-hydroxyl-terminated polydimethylsiloxane, which is distinguished by a viscosity of 80 Pa s at 25 ° C. (shear rate gradient D = 1 s ^"1 ) as component a).

2) 10.0 parts by weight of a mixture of monoalkylbenzenes with a density of 0.87 g / ml at 15 ° C, a kinematic viscosity of 58 mm ² / s at 40 ° C, a boiling point of 335 ° C and one average molecular weight of 350 g / mol, which under the trade name "Progyline 150 B" was obtained from Shrieve Products International Ltd. (component h)

3) 3.7 parts by weight of ethyltriacetoxysilane (component c) (not according to the invention)

4) 0.4 parts by weight of bis (ter-butoxy) diacetoxysilane (adhesive, component d) (not according to the invention)

5) 9.5 parts by weight of hydrophilic silica, which was obtained from Degussa under the name Aerosil® 150 (component b))

6) 0.01 part by weight of dibutyltin acetate (component f))

The silicone rubber compounds produced in this way are homogeneous, smooth, soft and stable (Boeing flow tests: 0 mm each). A satisfactory result (see Table 6) is not achieved when testing the paint compatibility or paintability. Despite the absence of an a / pfta, omega-trimethyl-terminated polydimethylsiloxane otherwise customary in RTV 1 K in the formulations and despite the use of the alkylbenzenes according to the invention, in a filled alkoxy system such as 10 A (alkoxy crosslinker component c) not according to the invention) and in an acetate system such as 10 B (acetate crosslinker, component c) not according to the invention), satisfactory wetting of the paints was not achieved.

Further properties of the silicone elastomer, produced according to 10, A: tensile stress at 100% elongation: 0.16 N / mm ² tensile strength: 0.59 N / mm ² , elongation at break 659%,

Shore A hardness: 11.

Volume shrinkage (ISO 10563): 4.1%, mass shrinkage (storage at 120 ° C, 24 hours): 3.7% Example 10 C

A silicone rubber mixture based on another neutral benzamide crosslinker according to formulation C according to the invention is produced.

1) 49.8 parts by weight of a linear a / pΛa, omega-hydroxyl-terminated polydimethylsiloxane as component a), which is characterized by a viscosity of 80 Pa s at 25 ° C (shear rate gradient D = 1 s ^"1 ).

2) 10.0 parts by weight of a mixture of monoalkylbenzenes with a density of 0.87 g / ml at 15 ° C, a kinematic viscosity of 58 mm ² / s at 40 ° C, a boiling point of 335 ° C and one average molecular weight of 350 g / mol, which was obtained under the trade name "Progyline 150 B" from Shrieve Products International Ltd. 3) 2.0 parts by weight of an a / p /? a, omega-bis ( diethoxy-3-propylamine) -terminated dodecamethylhexasiloxane as component d)

4) 30.0 parts by weight of ground chalk (CaCO ₃ ) as component e), which was surface-treated with stearic acid

5) 3.5 parts by weight of bis (N-methylbenzamido) ethoxy-methyl-silane (component c))

6) 4.5 parts by weight of hydrophobic silica as component b), which was obtained from Degussa under the name Aerosil® R 972

7) 0.2 part by weight resulting from a reaction of dioctyltin oxide and tetrapropyl silicate (45 to 55 parts by weight) as component f) The silicone rubber mixture produced in this way is homogeneous, supple, soft and stable (Boeing flow test: 0 mm). When examining the

Compatibility with paint or paintability becomes a very good paint sales

(see Table 6-) and very good paint adhesion (according to ASTM D-3359-78).

Further properties of the silicone elastomer 10 C:

Tensile stress at 100% elongation: 0.35 N / mm ² , tensile strength: 0.35 N / mm ² ,

Elongation at break 116%,

Shore A hardness: 26.

Volume shrinkage (ISO 10563): 4.7%,

Mass shrinkage (storage at 120 ° C, 24 hours): 5.4%

Table 6: Compilation of the paint courses

BESTATIGUNGSKOPIE Example 11, comparison:

According to Example 1, a silicone rubber mixture according to DE 3 025 376 is produced, but in which instead of 10.0 parts by weight of a mixture of monoalkylbenzenes with a density of 0.87 g / ml at 15 ° C., a kinematic viscosity of 58 mm ² / s at 40 ° C, a boiling point of 335 ° C and an average molecular weight of 350 g / mol as component h) 10.0 parts by weight of cyclohexane is used.

The silicone rubber mixture produced in this way is homogeneous, supple, soft and stable (Boeing flow test: 0 mm). The volume shrinkage of 17.1% determined according to ISO 10563 is significantly increased compared to the values found in Examples 1 to 3 (see Table 7), so the use of cyclohexane as an additive to adjust the coatability does not represent a complete solution to the problem, since the Volume shrinkage is too high.

Further properties of the silicone elastomer:

Tensile strength: 0.51 N / mm ² ,

Elongation at break 60%,

Shore A hardness: 45,

Volume loss (ISO 10563): 17.1%

Table 7: Comparison of the volume shrinkage values (ISO 10563)

Claims

claims:

1. Polyorganosiloxane composition obtainable by a process which comprises the mixing and reaction of the following components: a) at least one crosslinkable polyorganosiloxane, b) optionally a thickening or reinforcing filler c) at least one crosslinker selected from the group consisting of Oxime silane / siloxane crosslinking agents and benzamide silane / siloxane crosslinking agents exist, d) at least one aminoalkylalkoxysilane or siloxane, e) optionally an inert filler f) at least one organometallic catalyst g) optionally auxiliaries customary for RTV1 K compositions h) 1 to 18% by weight. -%, based on the total amount of the composition, alkyl aromatic compounds with an average molar mass of 200 to 500 g / mol in the respective compound class and a viscosity density

Constant (VDK) of at least 0.860.

2. Polyorganosiloxane composition according to claim 1, wherein component a) at least one compound of the general formula

is in which R and R ^{2 may be the} same or different, and each independently optionally substituted CrCι ₀ alkyl:, Cβ-Cu-aryl or C ₂ -C ₁₀ - alkenyl groups and R additionally for R ² ₂ SiO, R ¹ ₃ - _a R ² _a SiOo, 5, R ² SiO _3ι2ι or Q = SiO _4/2 , where R ¹ each independently represents hydrolyzable groups, n is an integer from 50 to 2500 and a = 0, 1 or 2.

3. polyorganosiloxane composition according to claim 1 or 2, wherein the crosslinking agent is selected from organosilicon compounds which have at least two groups --- Si-ON = CR ⁵ ₂ and / or ≡Si-N (R ² ) -C (= O) R ⁵ and alkoxy groups (-OR ² ) and wherein R ⁵ = R ^{2 are} as defined in claim 2.

4. A polyorganosiloxane composition according to any one of claims 1 to 3, wherein the aminoalkylalkoxysilane / siloxane has the formula (III) and / or (IV)

X- (CH ₂ ) _c -Si (OR ⁶ ) ₃ X- (CH ₂ ) _c -Si (OR ⁶ ) ₂ -O [Me ₂ SiO] _n Si (OR ⁶ ) ₂ - (CH ₂ ) ₀ - X

(III) (IV)

in which X is selected from -NH ₂ , -NHR ⁶ , -NR ⁶ ₂ -NHCH2CH2NH2, in which R ^{6 in} each case independently of one another optionally substituted linear or cyclic dC-io-alkyl-, Cβ-Cu-aryl-, C ₂ - Cιo-alkenyl or siloxane groups, where c is an integer and can preferably take values between 2 and 10, most preferably equal to 3.

5. Vulcanized elastic polyorganosiloxane compositions obtainable by reaction of the polyorganosiloxane compositions according to one of claims 1 to 4 by contacting them with water or steam at temperatures from 0 to 100 ° C.

6. Use of the vulcanized polyorganosiloxane compositions according to any one of claims 1 to 5 for the production of polyorganosiloxane compositions as joint seals, adhesives, moldings, profiles, coatings or molded-in-place seals

BESTATIGUNGSKOPIE

7. Use of the polyorganosiloxane compositions according to claims 1-4 for the production of joint seals, adhesives, profiles, moldings, coatings or molded-in-place seals which are paint-compatible to paintable both in the not yet crosslinked and in the crosslinked state.

8. Moldings, joint seals, profiles, coatings or molded-in-place seals according to claim 5, the surface of which at least partially has a lacquer coating.

BESTATIGUNGSKOPIE