CH645396A5 - FOAMABLE DIMENSIONS BASED ON SILICONE. - Google Patents

Description

The invention relates to a foamable mass based on silicone, which is capable, in particular at room temperatures or elevated temperatures, of forming fire-resistant insulating foams. Such masses are known per se; they contain a silicone polymer and various additives and can be cross-linked to form silicone elastomers. Those compositions which are based on the SiH / olefin / platinum system generally contain a vinyl-containing polysiloxane, a hydrogen-containing siloxane and a platinum catalyst and can be foamed at room temperature into a fire-resistant material for electrical systems and in particular for those in nuclear plants.

3,645,396

Such masses can react already at room temperature. The platinum catalyst is preferably solubilized if the components come into contact with one another. a platinum complex brought into solution, men. By incorporating inhibitors, one can achieve that is easily distributed in the components. Although it is certain that the mass only reacts at elevated temperature or platinum catalysts, such as platinum on carbon, to a certain degree. 5 degrees are usually only with one in solution

An example of a silicon-SiH-olefin-platinum-catalyzed or complexed platinum catalyst a used mass is described in US Pat. No. 3,436,366. In the barer foam are formed. A foamable composition is described for the formation ofrauchba-US-PS-3 425 967, which basically contains the following components: rem and reproducible silicone foam: vinyl-containing polysiloxane, Si - all types of platinum complexes in solution silicone resin with monofunctional and tetrafunctional inputs can be used .

an organic fibrous filler, such as asbestos or the vinyl-containing base polymer of the formula (1) can be fibrous potassium titanate, optionally a finely divided one of monofunctional units and tetrafunctional inorganic filler, a catalyst, an organic unit or of monofunctional, tetrafunctional and hydrogen polysiloxane and one external blowing agent. Assemble the goal of the bifunctional silicone units. In addition to US-PS-3 425 967 is a high-strength silicone foam which can also fillers, e.g. fibrous or reinforcing or formation of fire-retardant, but tough products uses customary stretching fillers can be incorporated into the mass. will.

External blowing agents, as they are necessary according to the patent mentioned. As examples of alkyl radicals with 1-8 carbon atoms in writing, methyl, ethyl, propyl have to be mentioned in addition to the resulting formulas. Examples cost the disadvantage that a further component is required 20 for aryl, in particular mononuclear aryl radicals, such as phenyl, and must be incorporated. The disadvantages include those of methylphenyl and ethylphenyl. One cup of blowing agent belongs to the fact that the mass must be brought to activation to the preferred example of fluoroalkyl residues with 3-8 carbon elevated temperatures. This in turn is 3,3,3-trifluoropropyl. Examples of cycloalkyl are difficult or impossible for the in situ formation of silicone cyclohexyl, heptyl and octyl.

foaming in nuclear plants or similar structures and it would be 25 The groups R and R 'in formula (1) are desirable according to one, if the foaming could also be achieved in room temperature, particularly preferred embodiment under methyl, tur. Phenyl and 3,3,3-trifluoropropyl selected.

The preferred viscosity range of the polymer (1) with temperature-foaming silicone mass as fire protection for electrical 25 ° C. is in the range from 2.5 to 250 Pa-s with a preferred system is in the US Pat. No. 3,923,705 described that 30 th vinyl concentration of the polymer from 0.0002 to 0.1 a silanol-containing polysiloxane with SiH substance in counter wt .-%. A correspondingly limited vinyl concentration expected from platinum catalyst, optionally at room temperature, enables a suitable reaction rate, i.e. forms a silicone foam or at elevated temperature. One that is not too small and yet sufficient and one disadvantage of this system is that it cannot work with suitable crosslinking of the elastomeric types of platinum catalysts that are available from the mass, but instead allows 35% silicone foam. The fastest type of the so-called Karsteadt-platinum viscosity of the mass is expediently not required to be highly complexed before foaming in accordance with US Pat. No. 3,775,452. chooses, because otherwise the mass is difficult to handle and to

Another disadvantage of such a flame retardant pour is. The viscosity of the base poly foam is preferably such that it does not have sufficient tensile strength for the mers at 25 ° C. between 1 and 250 Pa-s and in particular manufacture of products which have a sufficient range between 2.5 and 100 Pa -s. If the viscosity of the base requires rub resistance and toughness, e.g. Blankets or lymeren is kept low, the viscosity of the cladding is also. A disadvantage of silicone foam according to the US total mass is lower and then easier to handle PS-3 923 705 is the fact that the basic system is more manageable and pourable. Preferred base polymers which are essentially a silanol / SiH / platinum-catalyzed system, said 2 formula (3). The most before - up to 85% of the mass can be vinyl. Such a basic polymer of this type is thus present according to the For system with regard to crosslinking rates and usually (3) only vinyl groups in the siloxy end units. producible physical properties normally, however, it is possible to use a polymer in which, however, less reliable than a vinyl / SiH / olefin / platinum-only vinyl units in the siloxy units in the polymer-talysized system. chain present. How a silicone foam can be made

In order to use even more than 85% by weight vinyl, in which the vinyl units appear only in the siloxane chain, the properties of the silicone foam mass and in which no vinyl-terminated units in the polyme batch to batch are reliable and reliable reproducible to be available. Targeting such a vinyl-containing base polymer is, however, in DE-OS-2 906 214 a mass of vinyl-containing does not lead to a foam with such good physical properties such as polysiloxane, hydrogen-containing siloxane, platinum catalytic properties as in the case of a vinyl-containing polymer silicone foam made with sator and other ingredients and a small amount of ss vinylsiloxy end groups.

Water has been proposed that acts as a blowing agent. In another and preferred embodiment

Problems with the conventional compositions can thus be overcome as a vinyl-containing base polymer, although a polymer is used, but at the expense of the disadvantage that the vinyl units become both at the end of the poly-the water when the composition is left to stand as from the other chain would also separate constituents on the siloxy units of the polymer chain and therefore each sit just in front of the «o. While such a polymer must be incorporated into a suitable elasto-mixing or foaming. meren silicone foam is, is such a foam It was therefore desirable a silicone mass, which is not desirable and has not so good physical

Room temperature without the difficulties described properties, such as when foaming which ends in vinyl groups. Base polymer of formula (3) is used, the most

The invention relates to a foamable composition based on "most preferred polymer for the inventive composition silicone base, which composition is that specified in claim 1. Such vinyl-containing polymers have features in the art. Preferred embodiments of the mass are known and can also have the features of claims 2-10 by known methods. getting produced.

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The non-fluorinated polymers can be prepared by hydrolysis of the suitable diorganodichlorosilanes in water and subsequent cracking of the hydrolyzate with alkali metal hydroxide, preferably KOH, at elevated temperatures.

The distillation is conveniently carried out in equilibrium, i.e. at temperatures above 150 ° C in the presence of small amounts of potassium hydroxide and suitable chain terminators. For example, divinyl tetraorganodisiloxane chain terminators such as e.g. Divinyltetramethyldisiloxane chain terminators can be used.

The resulting mixture is heated to temperatures above 150 ° C. and can come into equilibrium until about 85% by weight of the cyclic tetrasiloxanes have been converted into the linear polymer of the desired viscosity. Now the mixture is cooled, the alkali metal hydroxide neutralized with a suitable weak acid such as phosphoric acid; Unreacted cyclic compounds are removed in order to obtain the desired vinyl-containing polymer as residue. In addition to vinyl-containing polymers of formula (3), those with vinyl in the polymer chain can also be obtained by balancing suitable vinyl-containing cyclic tetrasiloxanes, details of which can be found in US Pat. No. 3,425,967.

The second necessary constituent of the mass is 1 to 10 parts by weight of a silano group-containing organosilicon compound with a viscosity between 0.010 and 1 Pa-s at 25 ° C, the organic residues among alkyl residues with 1 to 8 carbon atoms, vinyl residues, aryl residues and cycloalkyl residues, fluoroalkyl residues with 3 up to 8 carbon atoms are selected. This component has a silanol group content of 2 to 10% by weight. A polymer having a viscosity of 0.01 to 0.1 Pa-s at 25 ° C. and a silanol group content of 5 to 10% and in particular of 7 to 10% by weight is preferred. This connection has two important aspects: first, there must be a silicone compound and second, it must have silanol groups. The silanol groups together with the hydroxide form the hydrogen, which forms the intumescent component that creates the foam in the mass. Consequently, any silane or siloxane that has a silanol group content in the range given above will work in this system. Furthermore, the silicone compound need not be linear, it can be branched or have any molecular arrangement as long as it has silanol groups that are easily condensable. It should be noted that although it has silanol content, silicone resin does not act as the compound because it does not release silanol groups very easily; when it releases silanol groups, it condenses to form a hard, brittle solid. Likewise, silanol groups in silicon dioxide fillers are practically not suitable as a source of silanol.

Organopolysiloxanes with a silanol content of over 10% by weight are difficult to access, while organopolysiloxanes with silanol contents of less than 2% by weight do not contain enough silanol to provide sufficient amounts of hydrogen gas to foam the mass. A silanol content of 5-10% by weight is particularly preferred. The silanol-containing silicone compound preferably has the formula (4) given in claim 8.

The polysiloxane is present in a concentration of 1 to 10 parts by weight per 100 parts by weight of the vinyl-containing base polymer of the formula (1). Less than 1 part does not release enough gas that creates a good Hefert foam. More than 10 parts are not useful and are a waste of the silanol material. In addition, more than 10 parts by weight of silanol-containing polysiloxane form too much hydrogen gas, which leads to large voids in the

System can lead. More preferably, 1 to 5 parts by weight of the silanol-containing polysiloxane as mentioned above is used. The third necessary component in the composition according to the invention is 1 to 50 parts by weight of a 5 hydride polysiloxane of the formula (2) given in claim 1. The limitation that the hydrogen content of the hydride-polysiloxane polymer is 0.3 to 1.6% by weight is important, since otherwise the hydride polymer does not have enough hydrogen atoms to react with water to release the hydrogen io substance and also add to the vinyl molecules of the vinyl-containing polysiloxane to form cross-linked silicone foam. If there is not enough hydride in the polymer, i.e. 0.3% lower weight limit, then there is not enough hydrogen in the polymer to crosslink with the vinyl-15-containing polymer.

Consequently, the hydrogen content of such a polymer must be strictly observed, such as the number of moles of water per mole of hydrogen-polysiloxane crosslinker. It should also be noted that the viscosity is quite important and that 2o z varies so that the viscosity of the polymer varies from 0.005 to 0.1 Pa-s and in particular from 0.005 to 0.040 Pa-s. In order for a reaction leading to the desired foam to proceed in the manner described, it is necessary for the hydride polymer of the formula (2) to contain hydrogen on the siloxane chain 25. Although it may have hydrogen atoms on terminal siloxy atoms, it must contain hydride atoms on the polymer chain for the desired reaction to take place. If there are no hydrogen atoms in the polymer chain of the hydride polymer, a suitable SiHcon foam 30 is not obtained. As a result, a hydride polymer with hydrogen atoms is not suitable only at the terminal siloxy atoms. In contrast, hydride polymers of the formula (20) given in claim 4 are often preferred.

The radical R2 is chosen from hydrogen, alkyl radicals 35 with 1 to 8 carbon atoms, cycloalkyl radicals, aryl radicals, e.g. with 6 to 8 carbon atoms and fluoroalkyl radicals with 3 to 8 carbon atoms and most preferably selected from methyl, phenyl and 3,3,3-trifluoropropyl. The radical R3 is selected from alkyl and aryl radicals having up to 8 carbon atoms. Desirably, the vinyl-containing polymer contains no hydrogen substituent groups, and there are no vinyl or aliphatic unsaturated substituent groups in the hydrogen-polysiloxane polymer of formula (2). 1 to 50 parts by weight of hydride-45 polysiloxane crosslinking agent of the formula (2) are used per 100 parts of vinyl-containing base polymers of the above formula (1). The preparation of the non-fluorinated hydrogen-substituted polysiloxane polymer is much easier than the preparation of the vinyl-containing polymer. The low-viscosity hydride-substituted polysiloxane polymers of this kind can be obtained by hydrolyzing the appropriate hydride-substituted dichlorosilanes with diorganodichlorosilanes with the appropriate amount of chain terminators, whether they are hydride-substituted or not.

55 Both in the production of vinyl-containing polymers of the formula (1) and in the production of the hydride polymer, the suitably substituted chain terminator can be any di-siloxane, trisiloxane or low-molecular weight linear polymer. With regard to the hydrolysis reaction in the manufacture of the hydride-polysiloxane polymer, a monofunctional silane with the suitable substituent groups is then used as chain terminator, such as hydrogendimethylchlorosilane, trimethylchlorosilane, 3,3,3-trifluoropropyldimeth-ylchlorosilane. Thus, chain terminators which are chlorosilanes with the appropriate substituent groups can be used to form the low viscosity and low molecular weight hydride-polysiloxane polymer crosslinkers of formula (2).

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Such low molecular weight polymers can also be obtained with 2 to 8 carbon atoms, cycloalkenyl with 5 to 7 carbon atoms.

Equilibration, i.e. by equilibrium of the atomic atoms or styrene. In the above formulas, especially suitable cyclic tetrasiloxanes with a very mild acidic olefins are ethylene, propylene, the various

catalyst, e.g. acid activated clay, e.g. Filtrol, isomers of butylene, octylene, cyclopentene, cyclohe-

with the appropriate chain terminators. 5 xen, cyclohepten etc.

It should also be noted that in the case of such equilibria, the platinum chloride-cynic acid catalyst, the platinum chloride-cyan acid catalyst, is used in the composition according to the invention as platinum weight adjustments, which material can be used at elevated temperatures, the equilibrium-adjusting clopropane complex (PtCl2- C3H6) 2, which is described in US Pat. Lungs preferably at temperatures above 90 and still 3 159 662. Further platinum-containing material is preferably carried out above 100 ° C., in order to bring the cycli- 10 a complex which is made of chloroplatinic acid and up to 2 tetrasiloxanes into equilibrium and about mol per g platinum of a representative from the group of the Alko-85% convert into the linear polymer, whereupon the acidic hole, ether, aldehydes and mixtures thereof are formed, catalyst is filtered off and the cyclic compounds as described in US Pat. No. 3,220,972.

be subtracted to give the desired linear polymer to the preferred one, not only as a platinum catalyst but also. 15 platinum compound also acting as a flame retardant additive

For the preparation of fluorinated polymers, manure is preferably a platinum-divinyltetramethyldisiloxane complex,

a slightly different way of working. In the case of the VI described in US Pat. No. 3,775,452. Generally, these nyl-containing base polymers of the formula (1) are formed, the appropriate type of platinum complex by reacting chloroplatinic acid with gne fluorinated cyclic tetrasiloxanes, preferably with 4 mol water of hydration with tetramethyldivinylsiloxane in Ge -

Chain terminators in the presence of certain basic catalysts of sodium bicarbonate in ethanol solution,

analyzers, such as cesium hydroxide, potassium silanolate, at tempe- There are generally many types of platinum

temperatures of about 90 ° C or slightly above are used in equilibrium, since the compositions according to the invention are brought to linear polymer with about 50 to 60% conversion - compared to certain types of platinum catalysts not with viscosities of at least up to 1000 Pa-s are as sensitive as with conventional masses of

To produce 25 ° C, the catalyst was then with a mild 25. However, within the scope of the invention, a preferred one is to neutralize the acid and withdraw the cyclic platinum catalyst from either that of U.S. Patent 3,220,972 or that to give the fluorinated polymer. U.S. Patent 3,775,452.

The fluorinated cyclic tetrasiloxanes are e.g. by For the latter preferred platinum catalyst

Hydrolysis of the appropriate fluorinated dichlorosilane and chloroplatinic acid with a vinyl-containing cyclotetrasiloxane followed by cracking of the hydrolyzate with KOH, 30 or a vinyl-containing, low molecular weight polysiloxane in which as much as possible the pure tetrasiloxanes obtained in the presence of an alcohol and a mild base such as Na . There is another preferred process for triumbicarbonate, implemented so that the platinum complex is practically

Preparation of such fluorinated polymers, i.e. a vinyl table is chlorine free. Such a catalyst can be used in the cracking of the hydrolyzate with KOH, and preferably 35, because of its polysiloxane polymers of the formula (1), which is fluorinated reactivity advantageous in the compositions according to the invention. The advantage of the platinum catalyst, as with distilling off the fluorinated cyclic trisiloxanes on e.g. of the catalyst of U.S. Patent 3,775,452 is that

Head of the column. The fluorinated cyclic tetrasiloxanes he is so reactive that the foam with good speed

can, if it forms with an alkali metal hydroxide catalyst and hydrogen gas is released rapidly, so that it can be brought into equilibrium, in which the desired low density is formed more rapidly than in or low-viscosity fluorinated substituted polymers, or 40 other types of Platinum catalysts.

be changed. Such cyclic trisiloxanes can also be noted that from chloroplatinic acid and a platinum complex formed in the presence of a weakly basic catalyst to form linear vinyl-containing siloxane material, other fluorine-substituted liquids are also reacted, i.e. can be used as a catalyst independently

on materials with viscosities in the range of 1 to 10 Pa-s, whether they are chlorine-free or not. But is a platinum com

at 25 ° C or below. A more detailed description of the 45 plex catalyst obtained by reacting a vinyl containing sil-

for the preparation of such fluorine-substituted polymers, as has been obtained oxane with a chloroplatinic acid and in which SiH / olefin addition reactions are used, the chlorine content has been considerably reduced,

is found in US Pat. No. 4,041,010. When using a fluorine-substituted gate with other properties and more advantageous.

Hydride-polysiloxane polymer of formula (2) can be obtained. There are other types of solubilized platinum catalyst

for the present purposes, it can be done by direct hearing, which can be used in this case. In contrast to drolysis of the suitable fluorosubstituted chlorosilanes, the inventions in the case of the masses of US Pat. No. 3,923,705 are

be. Finally, the mass according to the invention contains masses according to the invention compared to a special type of solvent.

1 to 250 ppm of a preferably solubilized platinum catalyst borrowed platinum catalyst is not sensitive. In front-

Talysators and in particular 1 to 200 ppm solubilized preferably platinum in the context of the invention

Platinum catalyst, preferably a stabilized platinum catalyst such as platinum / C, is not used, since such catalysts are complex, easily dispersed in the constituents and do not provide as good a foam as solubilized platinum.

with a faster reaction and shorter reaction times. However, with this reservation any kind of solvable

possible. made platinum catalyst according to the invention

Many types of platinum compounds can be used for these SiH / olefins. The more preferable is the platinum catalytic converter

Addition reactions are known, and such a platinum catalyst according to US Pat. No. 3,775,452, as previously explained, since these can also be used for the composition according to the invention is a very rapidly reacting catalyst which can be used well. The preferred platinum catalysts, especially foam supplies. With all of these components, a silicone

Such platinum foams are produced when optical clarity is required. In general, the vinyl polymer

compounds that are soluble in the reaction mixture. Store the polymer separately from the hydrogen polysiloxane. The tin compound can be selected from those of the formula (PtCl2-01efin) 2,65 platinum catalyst either in the vinyl or in the H (PtCl3-01efin), as in the US PS silanol compound and vinyl-containing polysiloxanes.

3 159 601. The olefin of these formulas can- If the hydride with silanol polysiloxane and the vinyl halide

can be any type of olefin, but is preferably an alkenyl-containing polysiloxane in the presence of the platinum catalyst.

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is mixed, the mass obtained releases hydrogen and mass 10-100 parts by weight of filler, based on 100 formed an elastomeric silicone foam. It should be noted that important parts of the vinyl-containing base polymer.

hibitors can be used in bulk, so that a preferred extender filler that can form the viscosity reactive one-component system that does not inappropriately increase the bulk is milled significantly at room temperature for up to several microseconds, which is also the Refractory properties of the finished silicon

nate, does not react, but can increase reacon foam at elevated temperatures. Other suitable stretching greases, i.e. at temperatures above 100 or 150 ° C within fillers are e.g. Titanium dioxide, zinc sulfide white (Lithopone),

seconds to get a good silicone foam. Zinc oxide, zirconium silicate, silicon dioxide airgel, iron oxide,

Therefore, an inhibitor can be used in the mass, which contains diatomaceous earth, calcium carbonate, glass fibers, magnesium

e.g. organopolysiloxane containing vinyl, such as methylvinylcyclooxide, chromium oxide, zirconium oxide, aluminum oxide, α-quartz,

tetrasiloxane. It can also contain triallyl isocyanurate and burned clay, carbon, graphite, etc.

be a dialkyl maleate. Examples of the use of Ma- When reinforcing fillers such as e.g. pyrogenic leats can be found in DE-OS-3 018 674. or precipitated silicon dioxide can be used, the vis-

The inhibitor can be kept at a concentration of 100 to higher in viscosity by adding the fillers

10,000 ppm, based on a total mass, cyclic polysiloxanes or silazanes are used, such as e.g.

the; however, the above ranges are only preferred ranges in U.S. Patent No. 2,938,009, U.S. Patent No. 3,024,126 and U.S.

since other areas may be used as described in PS-3,635,743 and 3,837,878. Such components,

how much inhibitor activity is desired. If too much inhibitory compounds, such as cyclic polysiloxanes, can also be incorporated for the treatment compound, this can be done with disadvantageous bulking fillers, since such a

Influences on the physical properties of the mass also have the viscosity increase due to stretching or making it difficult to relieve the reaction even with increased fillers. Another method of abatement

Temperatures to start. In general, the inhibitors of the increase in viscosity consist in the use of a

tor compounds in the range specified above are used in the mass, preferably potassium titanate. They are not used when the mass is in minutes according to US Pat. No. 3,425,967. You can also use a silicone resin as filler or filler for ten or even seconds in a manufacturing plant to mix toughness and tensile strength and an elastomeric one Silicon foam is made to increase the mass without increasing the viscosity in the uncured. If the silicone foam in situ in electrical conductors inappropriately increase and the flame retardant

holding lines of nuclear plants or other buildings reduce properties of the mass. For example, 100 parts of the vinyl-containing base polymer of the formula 1 in gene should preferably not be used, and the elastomeric silicone 30 the mass 10 to 100 parts by weight of organopolysiloxane with foam by mixing the components at room temperature. .., c- u .. • um * a tur generated 3 -SiO units and Si02 units are incorporated,

where R7 is one of vinyl residues and alkyl, aryl or fluorine. It may also be desirable to have a one-component alkyl residue, the ratio of mono-one system being formed in the presence of an inhibitor and all 35 Units is 0.5: 1 to 1: 1 and mix 2.5 to 10 components together, the inhibitor against mol% of Si atoms being silicon-bonded vinyl groups to prevent the components from reacting until they contain. Preferably the silicone resin is to be started with vinyl group reaction; then it is simply compatible with vinyl-containing polymers and disper-heat the resulting one-component system to increased yeast. The radical R7 is preferably an alkyl radical with a silicone foam generated up to temperatures. It is also possible to note that the polysiloxane containing silanol does not need to be a polysil atom, a vinyl residue or a fluoroalkyl residue with 3 to 8 carbon oxanes, an aryl residue with up to 8 carbon atoms, it can also be a silane be. So the lenstoffatomen. In particular, R7 is selected from alkyl-silanol-containing silicon compound, which is necessary for the formation of residues with 1 to 8 carbon residues, phenyl residues, vinyl-serifer-containing polysiloxane, a silanol-containing residue, the resin being the desired vinyl substitution ha-lan the desired silanol content, e.g. up to 33 45 ben, as previously stated. The production of such wt.% Silanol, and thus as a distributor for silanol resins, is known. In general, monofunctional in the mass in concentrations of 1 to 10, more preferably 1 trimethylsilane with tetrachlorosilane in the presence of a solvent with up to 5 parts per 100 parts of the vinyl-containing polymer in a water-immiscible solvent with water hydrolyzate acts to release with hydrogenpolysiloxane to obtain a silicone resin which is separated from hydrogen gas to form the silicone foam or to react in the water-immiscible organic. However, silanol-containing polysiloxane is accumulated over sila solvents such as toluene or xylene; then nol-containing silane in the composition according to the invention is separated from the hydrolysis mixture and then added again, since the silanol-containing polysiloxanes free the gaseous high wash with water from acid. Form the hydrogen obtained as the foaming gas better controlled and free resin in the solvent can then add to the vinyl polymer. 55 are added and mixed in, whereupon the solvent

Simply evaporate to produce articles with sufficient abrasion grease. So with this addition it is possible and tough, e.g. for use as a blanket, from a mass without any fibrous or silicon or as a dashboard or display panel, one can remove the cecia fillers and without the reinforcement problems of the elastomeric silicone foam by incorporating the fillers into a tough, elastomeric silicone foam with 0 Increase -200 parts by weight of filler. Usually 60 good abrasion resistance and toughness are to be formed, which is preferred as a filler for normal extenders, since the production of silicone foam cladding is more suitable, active fillers, such as pyrogenic or precipitated silicon-di-vinyl-containing silicone resin is light-oxide in the vinyl-containing polymer, the viscosity of the Mass may be too much more distributable. What is special is a vinyl-containing resin that rises; On the other hand, such fillers have the advantage that the physical properties, in particular the tensile strength, are composed of monofunctional and tetrafunctional units in the vinyl-containing polymer in a solution of the strength and the tear behavior of a silicone resin formed from the composition in a solvent Improve mixture of an elastomeric silicone foam. worked, whereupon the solvent is evaporated to

According to a preferred embodiment, the lead to a mixture of the two components that

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can form part of the double pack system. containing silicone compound, while SiH its

It should be noted that less than 10 parts by weight of the resin per concentration in the hydride polysiloxane of formula 2 denotes

Not to collect 100 parts of the vinyl-containing base polymer. If less than 1 mole of SiH compound per mole of silicon

Results and more than 100 parts by weight of anol group in the finished mixture is not sufficient.

no significant improvements compared to low-5 hydrogen gas released to produce a good foam to Ren amounts. Also, when will deliver more. If there is more than preferred, a suitable

Resin is present as the base polymer, the mixing of the mass results in gnet foam; then too much hydrogen gas becomes quite difficult. In addition, another can be dispensed into the mass and also in the finished silicone foam mass.

Resin type are mixed, which are from monofunctional hardened or unused hydride, which for hard, difunctional units, tetrafunctional units, the physical properties, the flame retardant egg

ten exists. This type of resin, which is also detrimental to the properties of the hardened silicone foam compound, can only be monofunctional compared to the first type of silicone resin. It is therefore extremely desirable that little

tional and tetrafunctional siloxy units, is at least 1 mole of SiH in the silicone hydride per mole of silanol group in a different type of resin than that in the inventive mass of the silano-containing silicone compound, as previously defined,

is applied. There are no additional advantages 15.

through the use of this second resin, which contains difunctional addition to the fire resistance or the flame retardant nelle siloxy units, with the exception that these reinforce properties of the silicone foam, an elasticizing influence on the mass can be added to the resin type. For example, it is also possible to incorporate a large amount of vinyl into 100 parts of the vinyl-containing base polymer of the resin, which is to be incorporated into a vinyl-containing base polymer 20 mei 1 0.1 to 10 parts of carbon black and preferably residual sulfur. Consequently, soot can be added to 100 parts of a vinyl mer. Low-sulfur types of soot provide basic polymers containing 10 to 100 parts by weight of a sili- the best flame-resistant properties in bulk. Be-konharz-polysiloxane polymers with (R7) 3SiO0i5 units, more preferably 0.5 to 2 parts of a low-sulfur Rus-R7SiO units and Si02 units can be incorporated, which is used per 100 parts of the vinyl-containing base polymer - whereby R7 is a monovalent hydrocarbon radical , the 25 be used. It should be noted that the additional amount of soot over the ratio of monofunctional units to tetrafunctional 2 parts is 0.5: 1 to 1: 1 for the fire resistance properties of units and contributes to the R7SiO units, but not to such a large extent. Therefore, the preferred amount corresponding to 1 to 10 mol% is present, based on the total number of moles of the silicone units in the carbon black used in the composition according to the invention, in order to give the composition fire resistance properties to copolymers, and 2.5 to 10 Mole% of silicon 30 impart 0.5 to 2 parts. Although 0.2 parts of residual sulfur atoms have vinyl groups bonded to silicon. So Russes the mass of certain fire resistance properties - with the only difference in this resin compared to the shade, he is desirably used in a previous resin the presence of difunctional siloxy amount of 0.5 parts to the most desirable units. Again the residue R7 can be obtained in the above units fire resistance or flame retardancy properties of this second resin with difunctional siloxy units ir-35.

gendeiner of the residues that for R7 when defining the only from the flame retardant properties of the silicone

monofunctional and tetrafunctional units of best foam can be further improved by

resin was given. R7 to which well-known flame retardant additives are added is particularly preferred

in the above resin among alkyl residues with 1 to 8 carbons, as long as they do not go into the basic reactions for

Substances and vinyl residues selected. In any case, the manufacture of the silicone foam must intervene and the platinum

the resin does not inhibit or poison the above concentration of vinyl units in the talysator in the SiH / olefin / platinum catalyst reactions of the above monofunctional and tetrafunctional residues. The mass is usually

Units and difunctional siloxy units to the Ge are produced in the form of two packages, the hydride units having, as discussed above. Again, it is kept separate and not clogged with the platinum catalyst.

the need for some vinyl concentration on the 45 is brought together. The vinyl sili

Ease of distribution of the resin in a vinyl containing materials and the silanol silicone materials with or

Base polymers and in the hardening of the silicone resin for finished platinum catalyst without packaging, and hydropoly

against silicone foam. This resin is practically packed like the siloxane without the platinum catalyst,

previous resin made, the only difference being that when the two packs are mixed together

that the silanes in the reaction mixture in the desired 50 react in the absence of inhibitors at room temperature ratios containing difunctional chlorosilanes, which with temperature to an elastomeric silicone foam. When using monofunctional chlorosilanes and tetrachlorosilanes inhibitors, it is possible to mi-react the components. It should be noted that the reaction components, which see and which significantly hydrolysed the formation of a silicone foam to verini hydrolysis mixture, hesitate in a relative proportion, depending on the inhibitor, but if such are in relation to one another, ie it is desirable to increase two different masses Temperatures are warmed, they cross-link the functional units in the finished silicone resin product to have an elasto within minutes or even seconds. Therefore, silicone foam can be used by using such silicone mers. By using resins, a real silicone foam can be produced without the need for inhibitors. Use of silica fillers and fibrous fillers. The following examples are intended to illustrate the fillers used and also without undue viscosity increase and are not intended to be limitations on the inventions of the composition. It should be noted that this thought. All parts in the examples are related to the genyl containing resin important for the flame retardant properties.

is not detrimental, but increases the tensile strength and toughness of the silicone foam. It should also be noted that at least one mole of silicon-SiH must be present per mole of silanol, <> 5. A mixture of 49.4 parts of a 72:28 micron was used to produce a desirable foam Terminal vinyl containing dimethylpoly-wise are 2 to 5 mol% SiH per mol silanol in the finished siloxanes with a viscosity of 3.5 Pa-s (at 25 ° C) for the mass. Silanol is said to affect the silanol content of the 72% silanol component and 80.0 Pa-s for the 28% component

645 396

produced. The low viscosity component had about 0.0015% vinyl while the high viscosity component had about 0.0005% vinyl. For this purpose, 7 parts of quartz of 5 μm, 0.6 part of carbon black, 12.5 ppm of platinum in the form of the catalyst of US Pat. No. 3,775,452.1 g of unions dimethylpolysiloxane with 7.3% silanol and 0.09 parts of methylvinylcyclotetrasiloxane added, to which 2 parts of hydrogen-lin.-polysiloxane with 1.5% silicon hydride and a viscosity of 0.018 Pa-s (18 cP) were added at 25 ° C. The system started to gel within 2 minutes. A flame retardant foam was obtained which had a specific weight of 0.48. In this example, the silanol-containing polysiloxane made up only 2% of the siloxanes. The molar ratio of SiH / SiOH was 6.99.

Example 2

A mixture of 46.8 parts of the same mixture of vinyl-containing polysiloxanes as in Example 1 was prepared, in which 6.6 parts of 5 nm quartz, 0.6 parts of carbon black, 12.5 parts of platinum as a catalyst according to US Pat. 3,775,452.2 parts of a linear silanol-containing polysiloxane of Example 1 with 7.3% silanol and a viscosity of 0.026 Pa-s at 25 ° C. and 0.9 part of methyl vinyl tetramer were added, for which purpose 3.7 parts of hydropolysiloxane with a viscosity of 0.018 Pa-s were given at 25 ° C and a hydride content of 1.5 wt .-%. Again a flame retardant foam with a specific gravity of 0.38 was formed. The hydroxylated siloxanes accounted for about 4% of the total hydroxylated and vinyl siloxanes.

Example 3

50 parts of a mass with 75% by weight of a vinyl-terminated polydimethylsiloxane with a viscosity of 80

8th

Pa-s and 25% by weight of an organosiloxane copolymer with trimethylsiloxane units, methylvinylsiloxane units and Si02 units with a ratio of 0.8 trimethylsiloxane units per Si02 unit and with an amount of 5 methylvinylsiloxane corresponding to 7.0% Silicon atoms as methylvinylsiloxane units.

The above mixture was catalyzed with 30 ppm platinum in the form of the catalyst according to US Pat. No. 3,775,452, for which purpose 3.3 parts of silanol-containing polysiloxane from Example 1 and 1.5 parts by volume of trimethyl-containing polymethylhydrogensiloxane with 1.5% hydrogen and a viscosity of 0.018 Pa-s (at 25 ° C) was given. The result was an extremely tough foam with a specific weight of 0.35.

15 Example 4

16.5 parts of a quartz filler and 20 ppm of platinum in the form of the catalyst according to US Pat. No. 3,775,452, based on the weight of the polysiloxanes, were added to 33.5 parts of the polysiloxane composition of Example 3. This mass 20 had a specific weight of 1.28. 0.25 part of water was added. 3.3 parts of hydrogenpolysiloxane from Examples 1 and 2 were added. After vigorous mixing, foaming took place to form a very tough, elastic foam with a specific weight of 0.31.

25% of the mass described in Example 3 was added as a crosslinking inhibitor at room temperature before the polymethylhydrogensiloxane was added. When the polymethylhydrogensiloxane was added, no reaction was observed at room temperature, the system remained a viscous liquid. After heating for 15 minutes at 150 ° C., the system crosslinked and foamed to an elastic foam with a specific weight of 0.41.

C.

Claims (12)

645 396 PATENT CLAIMS 1. Foamable mass based on silicone, characterized in that the mass contains: (A) 100 parts by weight of vinyl group-containing base polymer of the formula (1) R ' I. R-Si-0 ■ I. R ' R ' I. -Si-O- I. R ' R ' I. -Si-R I. R ' (1) in which R and R 'are chosen from alkyl radicals with 1-8 carbon atoms, cycloalkyl radicals, aryl radicals, vinyl radicals and fluoroalkyl radicals with 3-8 carbon atoms so that the polymer contains 0.0002 to 3% by weight of vinyl groups and x is chosen so is that the polymer has a viscosity of 0.1 to 1000 Pa-s at 25 ° C, (B) 1-10 parts by weight of organosilicon compound containing silanol groups and having a viscosity at 25 ° C. of 0.010 to 1 Pa-s, the organic groups having alkyl radicals 1-8 carbon atoms, cycloalkyl radicals, vinyl radicals, aryl radicals and fluoroalkyl radicals with 3-8 carbon atoms is selected so that the polymer has a silano group content of Has 2-10% by weight, (C) 1-50 parts by weight of hydride polymer of the formula (2) Phenyl and 3,3,3-trifluoropropyl means and z has the meaning given in claim 1. 5. Mass according to claim 1, characterized in that the platinum catalyst is a complex of platinum and a vin 5 ylgroup-containing polysiloxane. 6. Composition according to claim 1, characterized in that it also contains 10-100 parts by weight of organopolysiloxane copolymer with (R7) 3 SiO05 units and Si02 units, where R7 is vinyl, alkyl, aryl or fluoroalkyl, The ratio of monofunctional units to tetrafunctional units is 0.5: 1 to 1: 1 and 2.5 to 10 mol% of the silicon atoms carry vinyl groups bonded to silicon. 7. Composition according to claim 1, characterized in that i5 they also 10-100 parts by weight of organopolysiloxane-Co- polymer with (R7) 3SiO0.5 units, R7SiO units and Si02 units, where R7 is vinyl, aryl, alkyl or fluoroalkyl, the ratio of monofunctional units to di-functional units is 0.5: 1 to 1: 1 and the difunctional 20 functional units are present in an amount of 1-10 mol%, based on the total mol number of siloxane units in the copolymer, and wherein 2.5 to 10 mol% of the silicon atoms carry silicon-bonded vinyl groups. 8. Composition according to claim 1, characterized in that 25 the silanol group-containing silicone compound is one of the Formula (4) is R3 I. R2-SiO- I. R3 R3 I. SiO- I. H R3 I. -Si-R2 I. R3 R5 I. (2) 30 HO-S i-O- I. R5 R6 I. -Si-O I. R6 R5 I. -Si-OH I. R5 (4) t in which R2 is hydrogen, alkyl radicals with 1-8 carbon atoms, cycloalkyl, aryl or fluoroalkyl radicals with 3-8 carbon atoms and R3 alkyl radicals with 1-8 carbon atoms, aryl radicals or fluoroalkyl radicals with 3-8 carbon atoms, the polymer being the Formula (2) has a hydrogen content of 0.3 to 1.6% by weight and z is selected such that that the polymer has a viscosity of 0.005 to 0.1 Pa-s at 25 ° C, and (D) 1-250 ppm of a platinum catalyst. 2. Composition according to claim 1, characterized in that the vinyl group-containing base polymer has the formula (3) 35 45 R ' I. Vi-S i-O- I. R ' R ' I. -Si-O- I. R ' R ' I. - S i-Vi I. R ' (3) 50 where Vi is vinyl, R 'is methyl, phenyl or 3,3,3-trifluoropropyl and v is selected so that the polymer has a viscosity of 0.1 to 1000 Pa-s at 25 ° C. 3. Composition according to claim 1, characterized in that it contains an inhibitor which is an organocyclosiloxane containing vinyl groups, a trialkyl cyanurate, an alkyl maleate or a mixture of such substances. 4. Composition according to claim 1, characterized in that the hydride polymer has the formula (20) 60 in which R5, R6 are the same or different and are alkyl with 1-8 carbon atoms, vinyl, aryl, fluoroalkyl with 3-8 carbon atoms or hydroxyl groups and t is selected so that the polymer has a viscosity of 0.010 to 1 Pa at 25 ° C. s has. 9. Composition according to one of claims 1-8, characterized in that it contains filler in a proportion of up to 200 parts by weight. 10. Composition according to one of claims 1-9, characterized in that the platinum catalyst is a soluble platinum complex. 11. A method for producing a foamable composition according to claim 1, characterized in that the components mentioned in claim 1 are mixed. 12. Use of the mass according to any one of claims 1-10 for shielding an electrical system against fire by enveloping the electrical system in the mass and foaming to an elastomeric silicone foam. R3 ' ! H-SiO-I R3 ' R3 ' I. -SiO- I. H R3 ' I. -Si-H I. R3 ' (20) 65 - * Z in which R3 'is identical or different from the groups methyl,