GB2052540A

GB2052540A - Organopolysiloxane compositions which harden to give elastomers, at or above ambient temperature, in the presence of water

Info

Publication number: GB2052540A
Application number: GB8018634A
Authority: GB
Original assignee: Rhone Poulenc Industries SA
Current assignee: Rhone Poulenc Industries SA
Priority date: 1979-06-08
Filing date: 1980-06-06
Publication date: 1981-01-28
Also published as: GB2052540B

Abstract

Organopolysiloxane compositions which are stable on storage in the absence of water, harden to give elastomers, at or above ambient temperature, in the presence of water, and are essentially based on dihydroxylic polysiloxanes, fillers, polyalkoxylated organosilanes, amino compounds and metal compounds, are characterised in that the polyalkoxylated silanes correspond to the general formula R'xSi[(OCH2CH2)pOCH3]4-x, in which the symbol R' represents methyl, vinyl, allyl, methallyl and phenyl radicals and the symbols p and x represent zero or one.

Description

SPECIFICATION Organopolysiloxane compositions which harden to give elastomers. at or above ambient temperature, in the presence of water The present invention relates to organopolysiloxane compositions which are stable on storage in the absence of water, and which harden to give elastomers, at or above ambient temperature, generally between 50C and 350C, in the presence of water.

These compositions can be prepared by mixing mainly hydroxylic diorganopolysiloxane polymers, fillers, particular polyalkoxylated silanes, organic or organosilicon amino compounds and metal or organometallic salts of carboxylic acids.

Coin positions prepared by mixing constituents similar to those listed above are known. Some of these compositions are not stable on storage; they are then referred to as two-component compositions because they must be packaged in 2 different packs with, for example, the hydroxylic diorganopolysiloxane polymers, the fillers and the alkoxylated silanes in one of the packs and the amino compounds and the metal salts in the other pack.

This presentation in 2 packs is not very practical (especially for building applications, which are very frequently carried out in the open air).because it is necessary carefully to mix the contents of one of the packs with the contents of the other pack only at the time of use, and immediately to use the total amount of the compositions formed.

Other compositions are stable on storage; these are referred to as one-component compositions and are packaged in a single pack.

Thus U.S. Patents 3,161,614 and 3,170,894 describe compositions prepared by mixing diorganopolysiloxanes blocked at each end of their chain by a polyalkoxysiloxy unit, and hardening catalysts, such as organic or organosilicon amines. These compositions use diorganopolysiloxanes which are not readily available and are mainly obtained by reacting chloroalkoxysilanes with hydroxylic diorganopolysiloxanes; moreover, they harden slowly in air and this means that the assemblies jointed using these compositions must be stored in the workshops for at least several days.

U.S. Patent 3,686,357 describes compositions prepared by mixing diorganopolysiloxanes blocked at each end of their chain by a polyalkoxysiloxy unit, linear aminoalkylpolysiloxanes also blocked at each end of their chain by a polyalkoxysiloxy unit, and hardening catalysts. These compositions use two kinds of polysiloxanes and the preparation of each kind requires a special step. Furthermore, the viscosity of the compositions tends to increase during storage; this increase considerably hinders their extrusion through the nozzles of the cartridges in which they are usually packaged.

Japanese Application 53/102,956 describes compositions prepared by mixing organopolysiloxanes each having at least 2 silicon atoms bonded to alkoxy groups, crosslinking systems produced by heating alkoxylated silanes (or polysiloxanes) with tin salts of carboxylic acids, and alkoxylated aminoorganosilanes. These compositions use, on the one hand, organopolysiloxanes which are more difficult to obtain than the hydroxylic organopolysiloxanes, and, on the other hand, crosslinking systems which require a heating step for their preparation.

The present invention relates to one-component compositions which are prepared from readily accessible constituents, are remarkably stable on storage in the absence of water, and harden, at or above ambient temperature and in the presence of water, to give elastomers having good mechanical properties.

The compositions of this invention are formed by mixing: (A) 100 parts of a,w-dihydroxydiorganopolysiloxane polymers having a viscosity of at least 500 mPa.s at 250C and consisting of diorganosiloxy units of the formula fl2SiO, in which the symbols R, which are identical or different, represent alkyl or halogenalkyl radicals having from 1 to 8 carbon atoms, cycloalkyl or halogenocycloalkyl radicals having from 4 to 8 carbon atoms, alkenyl radicals having from 2 to 4 carbon atoms, aryl or halogenoaryl radicals having from 6 to 8 carbon atoms or cyanoalkyl radicals having from 3 to 4 carbon atoms, at least 50% of all these radicals being methyl radicals, (B) 5 to 200 parts of fillers, (C) 2 to 20 parts of polyalkoxylated organosilanes, (D) 0.5 to 1 5 parts of amino compounds chosen from amongst primary and secondary organic amines having a pKb of less than 5 in an aqueous medium and having a boiling point of at least 680C at atmospheric pressure, and the aminoorganosilanes corresponding to the general formula:: Y'NH(GtX)yGSi [(OCH2CH2)p"]3mY11m in which the symbol R" represents a methyl or ethyl radical, the symbol G represents an alkylene radical having from 1 to 5 carbon atoms, the symbol X represents an oxygen or sulphur atom, the symbol G' represents an alkylene radical having from 2 to 5 carbon atoms, the symbol Y' represents a radical of the formula (G"NH)kR"', in which the symbol G" represents an alkylene radical having from 2 to 6 carbon atoms, the symbol R"' represents a hydrogen atom or an alkyl radical having from 1 to 4 carbon atoms and the symbol k represents zero, one, two or three, the symbol Y', represents a methyl, vinyl or phenyl radical, the symbols p and y represent zero or one (if p represents one, the symbol R" only represents a methyl radical) and the symbol m represents zero, one, two or three, and (E) 0.005 to 3 parts of hardening catalysts chosen from amongst iron chelates, tin, iron and lead salts of carboxylic acids, organotin salts of carboxylic acids, the products resulting from the reaction of these organotin salts with alkyl titanates, and the products resulting from the reaction of diorganotin chlorides with alkyl esters of thioglycolic acid, and are characterised in that the organosilanes (C) correspond to the formula RtXSi [(OCH2CH2)pOCH3] 4-x in which the symbol R' represents a methyl, vinyl, allyl, methallyl or phenyl radical and the symbols p and x represent zero or one.

The ,-dihydroxydiorganopolysiloxane polymers (A) have a viscosity of at least 500 mPa.s at 250C and preferably of at least 3,000 mPa.s at 250C. They may be relatively non-viscous oils having a viscosity ranging from 500 mPa.s to 50,000 mPa.s at 250C, viscous oils having a viscosity ranging from 50,000 mPa.s to 1 million mPa.s at 250C, or rubbers having a higher viscosity which can exceed 50 million mPa.s at 250C. These polymers essentially consist of diorganosiloxy units of the formula R2SiO and are blocked at each end of their chain by a hydroxyl group; the term "essentially" means that the presence of monoorganosiloxy units of the formula F;SiO.5 and/or siloxy units of the formula SiO2 is not excluded if present in a proportion of at most 2%, relative to the number of diorganosiloxy units.

The symbols R are as defined above, that is to say they represent alkyl or halogenalkyl radicals having from 1 to 8 carbon atoms, such as methyl, ethyl, propyl, isopropl, butyl, pentyl, hexyl, 2- ethylhexyl, octyl, 3,3,3-trifluoropropyl, 4,4,4-trifluorobutyl and 4,4,4,3,3-pentafluorobutyl radicals, cycloalkyl or halogenocycloalkyl radicals having from 4to 8 carbon atoms, such as cyclopentyl, cyclohexyl, methylcyclohexyl, 2,3-difluorocyclobutyl and 3,4-difluoro-5-methylcycloheptyl radicals, alkenyl radicals having from 2 to 4 carbon atoms, such as vinyl, allyl and but-2-enyl radicals, aryl or halogenoaryl radicals having from 6 to 8 carbon atoms, such as phenyl, tolyl, xylyl, chlorophenyl, dichlorophenyl and trichlorophenyl radicals, and cyanoalkyl radicals having from 3 or 4 carbon atoms, such as p-cyanoethyl and y-cyanopropyl radicals.

The units of the formulae (CH3)2SiO, CH3(CH2=CH)SiO, CH3(C6H5)SiO, (C6Hs)2SiO, CF3CH2CH2(CH3)SiO, NC-CH2CH2(CH3)SiO, NC-CH(CH3)CH2(CH2=CH)Si0, NC-CH2CH2(C6H5)Si0 may be mentioned as an illustration of units represented by the formula R2SiO.

The polymers (A) are marketed by silicone manufacturers; furthermore, they can easily be manufactured by known techniques. One of the commonest techniques consists, in a first stage, in polymerising diorganocyclopolysiloxanes with the aid of catalytic amounts of alkaline or acid agents, and then in treating the polymers with calculated amounts of water (see, e.g. French Patents 1,134,005, 1,198,749 and 1,226,745); this added amount of water, which is the larger, the lower is the viscosity of the polymers to be prepared, can be totally or partially replaced by a,- dihydroxydiorganopolysiloxane oils having a low viscosity ranging, for example, from 5 to 200 mPa.s at 250C and having a high level of hydroxyl radicals.

In a second stage, the polymers are isolated by removing, at a temperature which is generally above 1 000C and under a pressure which is preferably below atmospheric pressure, the diorganocyclopolysiloxanes which are present when the reaction reaches equilibrium, and also the other polymers, of low molecular weight, which are formed during this reaction. Before distilling the volatile products, it is recommended to neutralise the alkaline or acid agents used as polymerisation catalysts.

The fillers (B) are used at a rate of 5 to 200 parts, preferably 10 to 150 parts, per 100 parts of a,w-dihydrnxydiorganopolysiloxane polymers (A).

These fillers can be presented in the form of very finely divided inorganic products having a mean particle diameter of less than 0.1 micron. These fillers include pyrogenic silicas, precipitation silicas, pyrogenic titanium oxide and aluminium oxide, and lamp-blacks.

They can also be presented in the form of more coarsely divided inorganic and/or organic products having a mean particle diameter of more than 0.1 micron; these fillers include ground quartz, diatomaceous silicas, calcium carbonate, calcined clay, titanium oxide of the futile type, the oxides of iron, zinc, chromium, zirconium and magnesium, the various forms of alumina (hydrated or nonhydrated), boron nitride, lithopone, barium metaborate, powdered cork, wood sawdust, phthalocyanines, inorganic and organic fibres, and organic polymers (polytetrafluoroethylene, polyethylene, polypropylene, polystyrene and polyvinyl chloride).

These fillers, and more especially the fillers of inorganic origin, can be surface modified by treatment with the various organosilicon compounds usually employed for this purpose. These organosilicon compounds include organochlorosilanes, diorganocyclopolysiioxanes, hexaorganodisiloxanes, hexaorganodisilazanes or diorganocyclopolysilazanes (see e.g. French Patents 1,126,884,1,136,885 and 1,236,505 and British Specification 1,024,234). In the majority of cases, the treated fillers contain from 3 to 30% of their weight of organisilicon compounds.

The purpose of introducing the fillers is to impart good mechanical characteristics to the elastomers which result from the hardening of the compositions according to the invention. It is possible to introduce a single filler or mixtures of several fillers.

Inorganic and/or organic pigments, and also agents for improving the heat resistance of the elastomers (e.g. salts and oxides of rare earths, such as ceric oxides and hydroxides) and/or the flame resistance of the elastomers, can be used in combination with these fillers. Organic halogen derivatives, organic phosphorus derivatives, and platinum derivatives, such as chloroplatinic acid (and the products resulting from its reaction with alkanols or ethers) and platinous chloride/olefine complexes, may be mentioned amongst the agents for improving flame resistance. These pigments and agents together generally represent at most 20% of the weight of the fillers.

The polyalkoxylated organosilanes (C) are used at a rate of 2 to 20 parts, preferably 3 to 1 5 parts, per 100 parts of the a,w-dihydrnxydiorganopolysiloxane polymers (A).

They correspond to the abovementioned formula: RtXSi [(0CH2CH2)pOCH3j4x As the symbol R' only represents a methyl, vinyl, allyl, methallyl or phenyl radical and the symbols p and x only represent the numbers zero and one, the alkoxylated silanes (C) form a very restricted group. This group in fact includes the silanes of the formula: Si(OCH3)4, Si(OCH2CH20CH3)4, CH3Si(OCH3)3, CH3Si(OCH2CH20CH3)3, CH2=CHSi(OCH3)3, CH2=CHSi(OCH2CH2OCH3)3, CHfflCH-CH2Si(0CH3)3, CH2=CH-CH2Si(0CH2CH2OCH3)3, CH2=C(CH3)CH2Si(OCH3)3, CH2=C(CH3)CH2Si(OCH2CH20CH3)3, C6H5Si(OCH3)3 and C6H5Si(OCH2CH20CH3)3.

Amongst these silanes, those of the formulae Si(OCH3)4, Si(OCH2CH20CH3)4, CH2=CHSi(OCH,)3, CH2=CH Si(OCH2CH20CH3)3, C6HsSi(OCH3)3, C6H5Si(OCH2CH20CH3)3 are preferred.

Alkoxylated silanes such as those of the formulae Si(OC2H5)4, Si(O n-C3H,)4, CH3Si(OC2H5)3, C6H5Si(OC2H5)3, although similar to the silanes (C) and usually employed in compositions which can be vulcanised in the cold, are not suitable; they lead to compositions which have poor stability on storage, which are difficult to extrude and/or which harden slowly in the atmosphere, for example over a period of more than 4 days.

The silanes (C) are widely used in the industry of organosilicon compounds; they are generally prepared by reacting the alcohol H(OCH2CH2)pOCH3 with the chlorosilane RtXSiCi4-x in the presence of an HCI acceptor, such as a tertiary amine.

The amino compounds (D) are used at a rate of 0.5 to 1 5 parts, preferably 1 to 12 parts, per 100 parts of the ,-dihydroxydiorganopolysiloxane polymers (A).

These amino compounds are primary or secondary organic amines or aminoorganosilanes.

The organic amines must possess a pKb of less than 5, preferably less than 4.5, measured in water, and a boiling point of at least 600C, preferably at least 750C, at atmospheric pressure.

These amines can be aliphatic, cycloaliphatic, heterocyclic or arylaliphatic.

The following may be mentioned as an illustration of aliphatic amines: the amines corresponding to the general formula (Y)sNH3~s, in which the symbol Y represents an alkyl group having from 4 to 25 carbon atoms when the symbol s represents one, and an alkyl group having from 1 to 25 carbon atoms when the symbol s represents 2; in the second case, the sum of the carbon atoms in the two radicals Y is generally from 5 to 30. The following amines may be mentioned as examples: n-butylamine, amylamine, the amines of the formulae:

n-decylamine, laurylamine, hexadecylamine, n-octylamine, di-(isopropyl)-amine, di (n-butyi)-arriine and di-(isobutyl)-amine.

the amines corresponding to the general formula M(NHQ)tNHM, in which the symbols M, which are identical or different, represent hydrogen atoms or alkyl radicals having from 1 to 10 carbon atoms, the symbol t represents one, two or three and the symbols Q (which can be identical or different if the symbol t represents two or three) represent alkylene radicals which have from 1 to 25 carbon atoms and which are unsubstituted or substituted by one or more NH2 radicals; the following amines may be mentioned as examples: ethylenediamine, propylenediamine, hexamethylenediamine and the poiyamines of the formulae:

H(NHCH2CH2)2NH2,.H(HNCH2CH2)3NH2, H2NCH2CH(NH2)CH2NH2- Cyclopentylamine, cyclohexylamine and the amines of the formulae:

may be mentioned as typical cycloaliphatic amines.

Piperidine, pyrrolidine, piperazine and the amines of the formulae:

may be mentioned as suitable heterocyclic amines.

Benzylamine and phenylethylamine may be mentioned as suitable arylaliphatic amines.

All these organic amines, and also the process for their preparation, are known; furthermore, a large number of them are available to industry.

The aminoorganosilanes (D) correspond to the abovementioned general formula: Y'NH(G'X)yGSi [(OCH2CH2)pOR"]3~mY"m- The meaning of the various symbols G, G', X, Y', Y", R", y, p and m, and also the meaning of G", R"' and k present in the group of the formula (G"NH)kR"', represented by Y', have already been given. In particular, the symbols G, G' and G" represent linear or branched alkylene radicals having, respectively, from 1 to 5 carbon atoms, from 2 to 5 carbon atoms and from 2 to 6 carbon atoms.

Taking account of the number of carbon atoms defined above, these alkylene radicals can be chosen from amongst those of the formulae: -CH2-, -CH2-CH2-, -(CH2)3-, -CH2-CH(CH34, CH2)4, -CH2-CH(CH3CH2-, -(CH2)5-, ACH,

The aminoorganosilanes can be divided into two groups, mamely those corresponding to the formula Y'NHGSi[(OCH2CH2)pOR"]3-m' Y"n, derived from the general formula in which y represents zero, and those corresponding to the formula Y'NHG'XGSl[(OCH2CH2)pOR"]3-mY"m' derived from the general formula in which y represents one.

Concrete examples which may be mentioned of organoaminosilanes of the first group are those of the formulae: (d)H2N(CH2)3Si(OCH2CH20CH3)3, H2N(CH2)3Si(OCH3)3, H2N(CH2)3Si(OC2H5)3, H2N(CH2)4Si(OCH3)3, H2NCH2CH(CH3)CH2CH2SiCH3(OCH3)2, H2NCH2Si(CH3)3, HN(n-C4Hg)CH2Si(CH3)3.

The preparation of these silanes is included in U.S. Patents 2,754,311,2,832,754 and 2,930,809 and in the article by L.H. Sommer and J. Rocket, published in J. Amer. Chem. Soc., 73, 5,130-5,134 (1951).

(2d) H2N(CH2)2NH(CH2)3Si(OCH3)3, H2N(CH2)2NH(CH2)3Si(OCH2CH2OCH3)3, CH3NH(CH2)2NH(CH2)3Si(OCH3)3, H(NHCH2CH2)2NH(CH2)3Si(OCH3)3), H2N(CH2)2NH(CH2)3Si(CH3)3,

The preparation of these silanes is included in U.S. Patent 2,971,864 and in the article by S.F.

Thames and L.H. Edwards, published in J. Chem. Soc., 2,339 (1968).

Concrete examples which may be mentioned of organoaminosilanes of the second group are those of the formulae: (d') H2N(CH2)30(CH2)3Si(OCH2CH20CH3)3, H2N(CH2)30(CH2)3Si(OCH3)3, C2H5NH(CH2)3O(CH2)3Si(OCH3)3, H2N--CH2--CH(CH3-)-CH2O(CH2)3SiC6H5(OCH3)2, H2N-CH2CH2NH(CH2)30(CH2)3Si(OCH3)3.

The preparation of these silanes is included in U.S. Patents 3,341,563,3,551,375 and 3,598,853.

(2d') H2N(CH2)2S(CH2)3Si(OCH2CH20CH3)3, H2N(CH2)2S(CH2)3Si(OCH3)3, H(NHCH2CH2)2S(CH2)3SiCH3(0CH3)2.

The preparation of these silanes is included in U.S. Patent 3,488,373.

The hardening catalysts (E) are used at a rate of 0.005 to 3 parts, preferably 0.01 to 1.5 parts, per 100 parts of a,-dihydrnxydiorganopolysiloxane polymers (A). They are chosen from amongst: (e) Iron chelates, such as iron acetylacetonate, tin, iron and lead salts of carboxylic acids, such as the 2-ethylhexanoate, the stearate, the oleate and the naphthenate of tin, lead and iron.

(2e) Organotin salts of carboxylic acids, such as dibutyltin diacetate or dilaurate, dimethyltin di-(2ethylhexanoate), dibutyltin diversatate, dioctyltin succinate and dioctyltin ma leate.

(3e) The products resulting from the reaction of the organotin salts described under (2e) with titanic acid esters, such as ethyl, n-propyl, isopropyl, n-butyl, 2-ethylhexyl and n-octyl titanate.

These products possess Ti--OO-Sn bonds; their preparation is included in French Patent 1,392,648 and British Specification 928,496.

(4e) The products resulting from the reaction of diorganotin dichlorides with alkyl esters of thioglycolic acid. These products correspond to the formula T2Sn(SCH2COOT)2, in which the symbols T, which are identical or different, represent alkyl radicals having from 3 to 20 carbon atoms.

Concrete examples of these products which may be mentioned are those of the formulae: (n-C4H9)2Sn(S-CH2C0O iso-C8H17)2 and (n-C8H17)2Sn(S-CH2C00 iso-C8H,7)2.

The preparation of these products is included, in particular, in French Patents 1,477,892 and 1,488,631 and in Canadian Patent 846,201.

Apart from the constituents A, B, C, D, and E, additives based on organopolysiloxane polymers can be present, they influence the physical characteristics of the compositions according to the invention and/or the mechanical properties of the elastomers obtained on hardening these compositions.

Amongst these additive", there should be mentioned more especially: (1 f) c',w-bis-(triorganosiloxy)-diorganopolysiloxane and/or a-(hydrnxy)-w-(triorganosiloxy)- diorganopolysiloxane polymers having a viscosity of at least 10 mPa.s at 250C and essentially formed of diorganosiloxy units and of at most 1% of monoorganosiloxy and/or siloxy units, the organic radicals bonded to the silicon atoms being chosen from amongst methyl, vinyl and phenyl radicals such that at least 60% of these organic radicals are methyl radicals. The viscosity of these polymers, in mPa.s at 250 C, can reach several tens of millions; the polymers therefore include oils having a fluid to viscous appearance and soft to hard gums.They can be prepared in accordance with the usual techniques which are more particularly described in French Patents 978,058, 1,025,150, 1,108,764 and 1,370,884. a,w-Bis-(trimethylsiloxy)-dimethylpolysiloxane oils having a viscosity ranging from 10 mPa.s to 1,000 mPa.s at 250C are preferably used. These polymers can be introduced at a rate of at most, say, 1 50 parts, preferably 5 to 120 parts, per 100 parts of a,cl)-dihydroxydiorganopolysiloxane oils (A).

(2f) liquid, branched methylpolysiloxane polymers having from 1.6 to 1.9 methyl radicals per silicon atom and consisting of a combination of units of the formulae: (CH3)3SiOo.5, ICH3)2SiO and CH3SiO1,5; the polymers generally contain from 0.2 to 10% of hydroxyl groups. They can be obtained by hydrolysing the corresponding chlorosilanes as shown in French Patent 1 408,662. These polymers can be introduced at a rate of at most, say, 70 parts, preferably 3 to 50 parts, per 100 parts of not dihydroxydiorganopolysiloxane polymers (A).

(3f) diorganopolysiloxane oils blocked by hydroxyl groups and/or lower alkoxy groups having from 1 to 4 carbon atoms, and having a low viscosity which is generally within the range 2 mPa.s to 4,000 mPa.s at 250C (if these oils are blocked solely by hydroxyl groups, their viscosity is less than 500 mPa.s at 250C); as above, the organic radicals bonded to the silicon atoms in these oils are chosen from amongst methyl, vinyl and phenyl radicals, at least 40% of these radicals being methyl radicals.

Methoxy, ethoxy, isopropoxy, propoxy, butoxy, isobutoxy and tert.-butoxy groups may be mentioned as chain-stopping lower alkoxy groups. The levels of hydroxyl and/or alkoxy groups generally range from 0.5 to 20%. These oils can be prepared in accordance with the usual techniques which are more particularly described in French Patents 938,292, 1,014,674, 1,116,196, 1,278,281 and 1,276,619. They can be introduced at a rate of at most, say, 50 parts, preferably 2 to 40 parts, per 100 parts of the a,o-dihydroxydiorganopolysiloxane polymers (A).

(4f) hydroxylic organosilicon compounds chosen from those corresponding to the general formula Z'SiZ2(0SiZ2)wOH, which are solid at ambient temperature. In this formula, the symbols Z, which are identical or different, represent methyl, ethyl, propyl, vinyl or phenyl radicals, the symbol Z' represents a hydroxyl radical or Z and the symbol w represents zero, 1 or 2.

Concrete examples of these compounds include diphenylsilanediol, methylphenylsilanediol, dimethylphenylsilanol, 1,1 ,3,3-tetramethyldisiloxanediol, 1 ,3-dimethyldiphenylsiloxanediol, 1 ,3- dimethyl-1 ,3-diethyldisiloxanediol and 1,1 ,5,5-tetramethyl-3,3-diphenyltrisiloxanediol. They can be introduced at a rate of at most, say, 30 parts, preferably 0.5 to 20 parts, per 100 parts of a,o- dihydroxydiorganopolysiloxane polymers (A).

The a bis-(triorganosiloxy)-diorganopolysiloxane and/or a-(hydroxy)-w-(triorganosiloxy)- diorganopolysiloxane polymers described under (if) can be totally or partially replaced by organic compounds which are inert towards the constituents A, B, C, D and E and which are miscible at least with the cr,-dihydroxydiorganopolysiloxane polymers (A). Concrete examples of these organic compounds include the polyalkylbenzenes obtained by alkylating benzene with long-chain olefines, in particular with the olefines containing 1 2 carbon atoms, which result from the polymerisation of propylene.

To prepare the compositions according to the invention, it is recommended to use equipment which permits both the intimate mixing, in the absence of moisture, of the constituents A, B, C, D and E and also, if appropriate, of the abovementioned adjuvants and additives, and the discharge of the volatile materials present (water and low molecular weight polymers).

These ingredients can all be introduced in a particular order. However, in order rapidly to obtain very homogeneous compositions and to avoid abrupt thickening of these compositions, it is preferable to proceed in 2 steps.

In a first step, the a,w-dihydroxydiorganopolysiloxane polymers (A), the possible adjuvants and/or additives and the fillers (B) are introduced and the whole is malaxated at a temperature which is preferably at least 700C and can exceed 1 500C, under a pressure which is preferably below atmospheric pressure, for a sufficient period of time, for example from 30 minutes to 5 hours, to remove the volatile products. The pastes thus obtained are homogeneous, anhydrous and stable on storage.

In a second step, the alkoxylated organosilanes (C), the amino compounds (D) and the hardening catalysts (E) are added to these pastes, in the absence of moisture and preferably at atmospheric pressure. The mixtures are malaxated at temperatures of, say, 20 to 1 000C for a time sufficient to obtain homogeneous compositions. A period of a few minutes, for example from 1 to 30 minutes, is generally suitable.

Alternatively, it is possible for the hardening catalysts (E) not to be added until after the formation of homogeneous mixtures resulting from the malaxation of the pastes with the alkoxylated organosilanes (C) and the amino compounds (D). During the preparation of these mixtures, it is possible to remove the alcohols originating from the reaction of the hydroxyl radicals of the a,- dihydroxydiorganopolysiloxane polymers (A) at least with the alkoxy radicals of the organosilanes (C); in this case, the mixtures should generally be heated at, say 50 to 1 200C for 30 minutes to 3 hours.

The compositions according to the invention are stable on storage in the absence of water and harden, at or above ambient temperature, in the presence of moisture. The hardening (or crosslinking) takes place from the outside to the inside of the bulk of the compositions. A skin is initially formed on the surface and the crosslinking then continues in the bulk. Complete formation of the skin (when the surface is no longer tacky to the touch) generally requires a period of time of 3 to 45 minutes and hardening in the bulk (making it possible to handle the elastomers formed) generally requires a period of 5 to 60 hours. These compositions exhibit the additional advantage of being very easy to use and after a storage period of one year, they still extrude satisfactorily.

Although they can be shaped, these compositions can be non-running on vertical supports.

Furthermore, once they have hardened to give elastomers, they can adhere to any substrate without the prior deposition of anchoring agents, provided, however, that component (D) is an aminoorganosilane having at least two alkoxy groups (0CH2CH2)pOR" bonded to the silicon atom, the symbols R" and p having the meaning indicated above, are used during the manufacture of these compositions.

The compositions can be employed for a variety of applications, such as jointing in the building industry, the joining of the most diverse materials e.g. metals, plastics, natural and synthetic rubbers, wood, cardboard, glazed earthenware, brick, glass, stone, concrete and masonry elements, the coating of woven or non-woven products based on glass fibres, organic fibres or synthetic fibres, the covering of sheets of metal or of a plastic or cellulosic material, the insulation of electrical conductors, the coating of electronic circuits and the preparation of moulds used for the manufacture of articles from synthetic resins or foams.

For certain applications, such as the impregnation of woven or non-woven articles, it is advantageous, and sometimes necessary, to disperse the compositions of the invention in inert organic diluents, such as toluene, xylene, heptane, white spirit, cyclohexane, methylcyclohexane, trichioroethylene, tetrachloroethylene, ethyl acetate or butyl acetate. The concentration of the compositions these dispersions is arbitrary; it can be chosen as a function of the amount of liquid absorbed by the materials to be treated, and as a function of the amount of composition to be deposited in order to obtain the desired effects, for example good water repellency or good insulating power.

The following Examples further illustrate this invention (the parts and the percentages being expressed by weight): EXAMPLE 1 70 parts of an a,w-dihydroxydimethylpolysiloxane oil having a viscosity of 50,000 mPa.s at 250C, 40 parts of an a,w-bis-(trimethylsiloxy)-dimethylpolysiloxane oil having a viscosity of 20 mPa.s at 250C, 3 parts of diphenylsilanediol, 15 parts of a pyrogenic silica having a specific surface area of 200 m2/g, and 45 parts of calcium carbonate having a mean particle diameter of 5 microns are introduced successively into a malaxator.

The contents of the malaxator are triturated for 2 hours at a temperature of 1 200C and under a pressure of 4,000 Pa. This results in the formation of an anhydrous homogeneous paste K, (171 parts).

The paste is left to cool to about 600C and the following are incorporated therein at this temperature: 7 parts of the silane of the formula CH2=CHSi(OCH2CH2OCH3)a,4 parts of the silane of the formula H2NCH2CH2NH(CH2)3Si(OCH3)3 and 0.1 part of a tin salt obtained by heating, at 11 00C for 3 hours, a mixture consisting of 100 parts of dibutyltin dilaurate and 27 parts of butyl titanate. This combination of the 2 silanes and the tin salt represents a crosslinking system K2.

The mixture is then malaxated for 5 minutes at 600C and this results in the formation of a homogeneous composition P, which does not flow in the vertical position; this composition is stored in a sealed container which is impervious to moisture.

(a) One portion of this composition P1 is spread, in the atmosphere (temperature 200C, relative humidity 10%), as a 2 mm thick layer, on a polyethylene plate which has been coated with a commercial detergent beforehand.

After an exposure time of 30 minutes, the layer is non-tacky to the touch, and, after 24 hours, it has changed into a rubbery film. When it is 7 days old, this film possesses the following mechanical properties: Shore A hardness (in accordance with French Standard Specification T 51,109) = 20.

Tensile strength (in accordance with French Standard Specification T 46,002) = 1.5 MPa.

Elongation at break (in accordance with French Standard Specification T, 46,002) = 600%.

Tear strength (in accordance with French Standard Specification T46,007) = 50 N/cm.

Elongation at tear (in accordance with French Standard Specification T 46,007) = 250%.

(b) Another portion of the composition P1 is used to manufacture test-pieces in accordance with ASA Standard Specification 116-1-1960, the method of manufacture of each test-piece being as follows: 2 square plates, having a side length of 50 mm and consisting of the material relative to which the adhesion of the composition which has been hardened to give an elastomer is to be measured, are placed face-to-face and 12 mm apart. The space created between the 2 plates is then totally blocked with wooden wedges, except for the central part of this space, so as to delimit a cavity having the dimensions 50 x 12 x 12 mm and extending from one edge of the plates to the other. This cavity is filled with the composition, the whole is left for 28 days at ambient temperature and the wedges are removed in order to release the test-piece.The latter thus comprises 2 plates of the same material, which are attached to one another, along one of their median lines, by a parallelpipedal bar of elastomer.

The test-pieces manufactured in this way are divided into 3 batches of equal size and the testpieces making up each batch differ from one another in the nature of the material forming the plates, this material being chosen from glass, aluminium, concrete, fir and polyvinyl chloride (PVC).

(i) first batch the tensile strength (TS) of the test-pieces, and also the corresponding elongation (E/B), are measured using a tensile tester actuated in accordance with the recommendations of ASA Standard Specification 116-1-1960. The results are summarised in Table 1 below.

TABLE 1

Materials mechanical Materials properties Glass Aluminium Concrete Fir PVC TS in MPa 0.6 0.65 0.59 0.68 0.66 E/B in % 490 450 410 380 430 All the breaks are cohesive and they occur in the bulk of the bar of elastomer; thus, there are no adhesive breaks characterised by detachment of the bar at the level of its zones of contact with the plates.

(ii) second batch: the test-pieces are placed under tension by subjecting them to an elongation of 1 50% with the aid of wedges, and the condition of the test-pieces is examined 24 hours after this applicatiori of tension; it is found that all the test-pieces pass the test and that there are no cohesive or adhesive breaks.

(iii) third batch: the test-pieces are immersed in water at 250C for 96 hours, they are then placed under tension by subjecting them to an elongation of 1 50%, and the condition of the test-pieces is examined 24 hours after the application of tension; it is again found that all the test-pieces pass the test.

(c) A third portion of the composition P, is introduced into aluminium tubes each having a capacity of 100 cm3; these tubes are then closed and left for 48 hours in an oven heated to 100 C.

After cooling the containers to about 200 C, their contents are spread, as a 2 mm thick layer, on a polyethylene plate which has been coated with a commercial detergent beforehand; it is found that the deposited layer behaves in essentially the same way as the layer described under (a), with a touch-dry time of 30 minutes and a crosslinking time of 24 hours. When it is 7 days old, the rubbery film formed has the following properties: Shore A hardness = 18 Tensile strength = 1.1 MPa Elongation at break = 550% Tear strength = 45 N/cm Elongation at tear = 200% (d) A fourth portion of composition P, is taken after a storage period of 8 months in a container impervious to moisture.

This portion is tested as described under (a): the touch-dry time of the deposited layer is found to be 25 minutes and the crosslinking time of this layer is found to be 20 hours.

The mechanical properties of the resulting film are as follows: Shore A hardness = 20 Tensile strength = 1.4 MPa Elongation at break = 500% Tear strength = 55 N/cm Elongation at tear = 180% (e) By way of comparison, 5 compositions P'" P"1, P"'" P41 and P51 are prepared in accordance with the procedure employed for preparing the composition P1, except that the constituents of the crosslinking system K2 are modified in the following manner: composition P'1: the tin salt is not used.

composition P"1: the silane H2N(CH2)2NH(CH2)3Si(OCH3)3 is not used; however, in order to retain the same level of alkoxy groups, bonded to the silicon atoms, as in the composition P1, 12.2 parts of the silane CH2=CHSi(OCH2CH2OCH3)3 are introduced instead of 7 parts.

composition P"'1: the silane CH2=CHSi(OCH2CH2OCH3)3 is not used; however, in order to have the same level of alkoxy groups, bonded to the silicon atoms, as in the composition P1, 9.6 parts of the silane H2N(CH2)2NH(CH2)3Si(OCH3)3 are introduced instead of 4 parts.

composition P41: the 7 parts of the silane CH2=CHSi(OCH2CH20CH2)3 are replaced by 5 parts of the silane Si(OC2H5)4, and the 0.1 part of the tin salt is replaced by 0.02 part of the same salt (if 0.1 part of this salt is used, the composition becomes very thick and can no longer be extruded).

composition P51: the 7 parts of the silane CH2=CHSi(OCH2CH2OCH3)3 are replaced by 4 parts of the silane CH3Si(OC2H5)3, and the 0.1 part of the tin salt is replaced by 0.02 part of the same salt (if 0.1 part of this salt is used, the composition can no longer be extruded).

These compositions are examined in accordance with the tests used with the composition P1, and the following results are recorded: Composition P'1: when exposed to the atmosphere in the form of a 2 mm thick layer, this composition crosslinks unsatisfactorily; thus, after an exposure time of 7 days, it has still not changed into a film of elastomer which can be stripped.

Composition P"1: this composition does not keep in a container impervious to moisture; it solidifies after a storage time of 30 hours.

Composition P"'1: when exposed to the atmosphere in the form of a 2 mm thick layer, this composition hardens in 48 hours; however, the stripped film does not have good mechanical properties; in particular, after ageing for 14 days, it possesses a Shore A hardness of 5 and a tensile strength of 0.2 MPa.

Composition P4r: after a treatment in which it is enclosed in aluminium tubes and heated for 48 hdurs at 100 C, this composition does not harden further; when exposed to the atmosphere, the deposited layers remain constantly pasty.

Composition P51: when heated as indicated above, for 48 hours at 100 C, this composition hardens unsatisfactorily on subsequent exposure to the atmosphere; it is necessary to wait 1 5 days in order to obtain a film of elastomer which can be stripped.

EXAMPLE 2 2 compositions P2 and P3 are prepared by following the procedure employed for preparing the composition P1 described in Example 1, except that the constituents of the crosslinking system K2 are modified as follows: Composition P2: the 4 parts of the silane H2N(CH2)2NH(CH2)3Si(OCH3)3 are replaced by 5.5 parts of the silane H2N(CH2)2NH(CH2)3Si(OCH2CH2OCH3)3.

Composition P3: the 7 parts of the silane CH2=CHSi(OCH2CH2OCH3)3 are replaced by 8 parts of the silane SifOCH2CH2OCH3)4, and 0.05 part of the tin salt is used instead of 0.1 part.

(a') One portion of each of these 2 compositions is spread, as a 2 mm thick layer, on a polyethylene plate in accordance with the process described under (a) of Example 1.

The touch-dry time and the hardening time of the deposited layers, and also the characteristics of the films of elastomers formed, when the films are 7 days old, are then recorded. The numerical results are summarised in Table 2 below: TABLE 2

charac teristics Touch Harden- Elonga- Elonga dry ing Tensile tion Tear tion at compo- time in time in Shore A strength at break strength tear in sitions minutes hours hardness in MPa in % in N/cm deposited P2 25 24 15 1.1 700 40 350 P3 10 12 L 20 1.5 600 50 170 (b') Another portion of each of these 2 compositions is used to manufacture test-pieces in accordance with ASA Standard Specification 13 6--11-1 960, each test-piece being manufactured in accordance with the process given under (b) of Example 1.

The test-pieces are divided into 3 batches of equal size and each batch is subjected to one of the tests also described under (b) of Example 1.

(i) first batch: the results relating to the measurement of the tensile strength (TS) and of the corresponding elongation (E/B) of the test-pieces are summarised in Table 3 below: TABLE 3

Materials form ing the plates or the test pieces Mechanical pieces Glass Aluminium Concrete FIR PVC Steel properties TS in MPa 0.7 0.7 0.8 0.8 0.7 0.65 E/B in % 550 520 400 450 500 600 TS ) TS in MPa 0.6 0.5 0.6 0.5 0.55 0.5 P3 l E/B in % 600 300 400 300 ~1 350 600 (ii) second batch: the test-pieces are placed under tension by subjecting them to an elongation of 150%; these test-pieces are examined after an extension time of 24 hours and it is found that they pass the test; there are no cohesive or adhesive breaks.

(iii) third batch: the test-pieces are immersed in water at 250C for 96 hours and are then placed under tension as above.

These test-pieces are examined after an extension time of 24 hours and it is found that they pass the test.

(c') A third portion of each of the compositions P2 and P3 is treated in accordance with the process described under (c) of Example 1, namely by introducing the compositions into aluminium tubes, closing the tubes and heating for 48 hours at 100 C.

After this accelerated ageing stage, the properties of the compositions are measured in accordance with the tests used above; it is found that the touch-dry time and hardening time are of the order of those included in Table (2), that the films of elastomer have essentially the same mechanical properties as those included in Table (2), and that the adhesion to ASA test-pieces has virtualiy the same values as those summarised in Table (3).

EXAMPLE 3 90 parts of an a,w-dihydrnxydimethylpolysiloxane oil having a viscosity of 100,000 mPa.s at 250C, 30 parts of a mixture of organic products which has a viscosity of 90 mPa.s at 250C and consists of a distillation cut of branched dodecylbenzene having a boiling range of 302--38506 at atmospheric pressure, 2 parts of an a,w-dihydroxymethylphenylpolysiloxane oil having a viscosity of 350 mPa.s at 250C, 12 parts of a pyrogenic silica having a specific surface area of 1 50 m2/g, and 70 parts of calcium carbonate having a mean particle diameter of 5 microns are introduced successively into a malaxator.

The contents of the malaxator are triturated for 3 hours at a temperature of 1 000C and under a pressure of 5,000 Pa. The paste (202 parts) thus formed is left to cool to about 600C and the following are incorporated therein at this temperature: 5 parts of the silane of the formula CsH5Si(OCH3)3, 4.5 parts of the silane of the formula H2N(CH2)3Si(OCH3)3 and 0.05 part of dibutyltin diacetate.

The whole is malaxated for 3 minutes at 600C.

The resulting composition is stored in a closed container impervious to moisture.

One portion of this composition is spread, as a 2 mm thick layer, on a polyethylene plate in accordance with the process described under (a) of Example 1. The behaviour of the deposited layer, and also the characteristics of the rubbery film formed, when it is 7 days old, are then noted.

The results are as follows: Touch-dry time = 20 minutes Hardening time = 18 hours Shore A hardness = 25 Tensile strength in MPa = 1.3 Elongation at break in % = 500 Tear strength in N/cm = 50 Elongation at tear in % = 180 Another portion of this composition is heated at 1 000C for 48 hours in accordance with the process described under (c) of Example 1.After cooling to 250C, the composition is spread, as a 2 tnm thick layer, on a polyethylene plate and the behaviour of the deposited layer, and also the mechanical properties of the film of elastomer formed, when it is 7 days old, are recorded; the results are as follows: Touch-dry time = 25 minutes Hardening time = 20 hours Shore A hardness = 27 Tensile strength in MPa = 1.1 Elongation at break in % = 550 Tear strength in N/cm = 45 Elongation at tear in % = 1 50 EXAMPLE 4 3 different compositions P4, P5 and P, are prepared by adding, to the paste K, (1 71 parts) prepared in Example 1, one of the crosslinking systems below: Composition P4: 6.4 parts of the silane of the formula Si(OCH3)4, 3 parts of the amine of the formula:

and 0.1 part of dibutyltin dilaurate.

The paste K1, the silane Si(OCH3)4 and the amine are first heated in the malaxator for 2 hours at 1 000C at atmospheric pressure. During this heating, about 1.3 parts of methanol are collected.

The dibutyltin dilaurate is then added to the contents of the malaxator, cooled to about 500 C.

Composition P5: 11 parts of the silane of the formula CH3Si(OCH2CH2OCH3)3,3 parts of noctylamine of the formula CH3(CH2),NH2 and 0.1 part of dibutyltin dilaurate.

In a first stage, the paste Ks, the silane and the amine are heated in the malaxator for 6 hdurs at 11 00C under a pressure of 5,000 Pa; about 5 parts of the alcohol CH3OCH2CH2OH are evolved during this treatment. In a second step, the tin salt is.introduced into the contents of the malaxator, cooled to about 500C.

Composition P": 6 parts of the silane of the formula CH3Si(OCH3)3, 4 parts of the diamine of the formula H2NCH2CH2CH(CH3)CH2C(CH3)2CH2NH2 and 0.1 part of dibutyltin dilaurate.

In a first stage, the paste K1, the silane and the amine are heated in the malaxator for 6 hours at about 800C at atmospheric pressure; about 2 parts of methanol are evolved during this treatment. In a second stage, the tin salt is introduced into the contents of the malaxator, cooled to about 450C.

One portion of each of these 3 compositions is spread, in the atmosphere, as a 2 mm layer, on a polyethylene plate in accordance with the process described under (a) of Example 1. The behaviour of the deposited layers, and also the characteristics of the films formed, when the films are 7 days old, are then recorded.The numerical results are summarised in Table 4 below: TABLE 4

s s Characteristics Touch-dry Hardening Tensile Elongation time in time in Shore A strength at break minutes minute hours hardness in MPa in % Composltio P4 16 36 15 1.3 470 PS 14 44 13 1.1 600 15 15 50 14 1.2 550 Another portion of each of these 3 compositions is subjected to accelerated ageing by heating for 48 hours at 1 000C in accordance with the process described under (c) of Example 1.

It is found that the behaviour of these aged compositions is essentially identical to the behaviour of the above compositions which have not been subjected to heat treatment.

EXAMPLE 5 3 compositions P7, P8 and P9 are prepared by adding, to the paste K1 (171 parts) prepared in Example 1, one of the crosslinking systems below: Composition P,: 11 parts of the silane of the formula Si(OCH2CH20CH3)4,1 part of piperidine, 6 parts of the silane of the formula H2N(CH2)2NH(CH2)2NH(CH2)3Si(OCH3)3 and 0.1 part of dibutyltin dilaurate.

The mixture consisting of the paste K1 and of the above crosslinking system is malaxated for 10 minutes at 600C.

Composition P8: 7 parts of the silane of the formula CffH5Si(OCH2CH2OCH3)3,2 parts of ethylenediamine, 4 parts of the siiane of the formula H2N(CH2)3O(CH2)3Si(OCH3)3 and 0.1 part of dibutyltin diacetate.

In a first stage, the paste K1, the 2 silanes CHsSi(OCH2CH2OCH3)3 and H2N(CH2)3O(CH2)3Si(OCH3)3 and the ethylenediamine are heated in the malaxator at 600C for 2 hours, and in a second stage, the tin salt is introduced into the contents of the malaxator, cooled to about 500C.

Composition P9: 6 parts of the silane of the formula CH2=CHSi(OCH3)3,1.5 parts of the amine of the formula CH3(CH2)3NH2, 4 parts of the aminosilane of the formula H2N(CH2)2S(CH2)3Si(OCH3)a and 0.1 part of dibutyltin diacetate.

One portion of each of these 3 compositions P7, P8 and P9 is spread, in the atmosphere, as a 2 mm thick layer, in accordance with the process described under (a) of Example 1. The behaviour of the deposited layers, and also the characteristics of the films formed, when the films are 7 days old, are then recorded.The numerical results are summarised in Table 5 below: TABLE 5

Characteristics Touch-dry Hardening Tensile Elongation time In time in Shore A strength at break positions minutes hours hardness in MPa in % Comp 12 16 19 1.5 550 15 18 20 1.2 450 16 20 18 1.3 500 Another portion of each of these 3 compositions is used to manufacture test-pieces in accordance with ASA Standard Specification 11 6-1-1 960. The process for the manufacture of each test-piece is the one described under (b) of Example 1; however, the material constituting the plates of the testpieces is based solely on aluminium.

The results relating to the measurement of the tensile strength (TS) and of the elongation at break (E/B) of the test-pieces are summarised in Table 6 below: TABLE 6

I Compositions P7 P8 P9 Properties TS in MPa 0.7 0.6 0.55 E/B in % 250 200 230 All these breaks are cohesive.

Another portion of each of these 3 compositions is subjected to accelerated ageing by heating at 1 000C for 48 hours in accordance with the process indicated under (c) of Example 1. The recorded behaviour of these aged compositions is essentially identical to the behaviour of the above compositions which have not been subjected to heat treatment.

EXAMPLE 6 100 parts of an a,et)-dihydroxymethylphenylpoiysiloxane oil having a viscosity of 30,000 mPa.s at 250C and consisting of 94 mol % of (CH3)2SiO units and 6 mol% of (C6Hs)2SiO units, 15 parts of a pyrogenic silica having a specific surface area of 300 m2/g and treated with octamethylcyclotetrasiloxane, and 5 parts of an a,o-dimethoxymethylphenylpolysiloxane oil having a viscosity of 50 mPa.s at 250C and consisting of 70 mol % of (CH3)2SiO units and 30 mol % of (C6Hs)2SiO units are introduced successively into a malaxator.

The contents of the malaxator are mixed for 3 hours at a temperature of 1 1 OOC and under a pressure of 5,000 Pa. The resulting paste (119 parts) is left to cool to about 600C and the following are incorporated therein: 7 parts of the silane of the formula CH2=CH-CH2Si(OCH2CH2OCH3)3, 4 parts of the silane of the formula H2N(CH2s3O(CH2)3Si(OCH2CH2OCH3)3 and 0.1 part of dibutyltin dilaurate.

The whole is malaxated for 3 minutes at 600 C. The resulting composition is divided into 2 portions. One of the portions is spread, in the atmosphere, as a 2 mm thick layer, on a polyethylene plate in accordance with the process described under (a) of Example 1. The behaviour of the deposited layer, and also the characteristics of the rubbery film formed, when it is 7 days old, are then noted. The results are as follows: Touch-dry time = 30 minutes Hardening time = 22 hours Shore A hardness = 20 Tensile strength in MPa = 1.7 Elongation at break in % = 350 The other portion is heated at 1 000C for 48 hours in accordance with the process described under (c) of Example 1. After cooling, this portion is also spread, in the atmosphere, as a 2 mm thick layer and the following numerical results are recorded: Touch-dry time = 40 minutes Hardening time = 25 hours Shore A hardness = 18 Tensile strength in MPa = 1.3 Elongation at break in % = 250 EXAMPLE 7 100 parts of an a,o-dihydroxymethylvinylpolysiloxane oil having a viscosity of 4,000 mPa.s at 250C and consisting of 97 mol % of (CH3)2SiO units and 3 mol % of CH3(CH2=CH)SiO units, 20 parts of a pyrogenic silica having a specific surface area of 300 m2/g and treated with octamethylcyclotetrasiloxane, and 20 parts of ground quartz having a mean particle diameter of 5 microns are introduced successively into a malaxator.

The contents of the malaxator are mixed for 3 hours at 1 1 OOC and under a pressure of 4,500 Pa; the resulting paste (139.5 parts) is left to cool to about 500C and the following are incorporated therein: 10 parts of the silane of the formula Si(OCH2CH2OCH3)4,5 parts of the silane of the formula H2N(CH2)2S(CH2)3Si(OCH3)3 and 0.1 part of dibutyltin diacetate.

The whole is malaxated for 5 minutes at 500C. The resulting composition is then divided into 2 portions. One of the portions is spread, in the atmosphere, as a 2 mm thick layer in accordance with the process described under (a) of Example 1. The behaviour of the deposited layer and the characteristics of the film formed, when it is 7 days old, are then noted. The results are as follows: Touch-dry time = 8 minutes Hardening time = 10 hours Shore A hardness = 59 Tensile strength in Mpa = 2.7 Elongation at break in % = 1 50 The other portion is heated for 48 hours at 1 000C in accordance with the process described under (c) of Example 1; after cooling, this portion is also spread, in the atmosphere, as a 2 mm thick layer and the following numerical results are recorded: Touch-dry time = 8 minutes Hardening time = 12 hours Shore A hardness = 62 Tensile strength in Mpa = 3.2 Elongation at break in % = 120

Claims

1. An organopolysiloxane composition capable of forming an elastomer in the presence of water, obtained by mixing: (A) 100 parts (by weight) of a,eo-dihydroxydiorganopolysiloxane polymer having a viscosity of at least 500 mPa.s at 250C and consisting essentially (as hereinbefore defined) of diorganosiloxy units of the formula R2SiO, in which the symbols R, which are identical or different, represent alkyl or halogenalkyl radical having from 1 to 8 carbon atoms, cycloalkyl or halogenocycloalkyl radical having from 4 to 8 carbon atoms, an aikenyl radical having from 2 to 4 carbon atoms, an aryl or halogenoaryl radical having from 6 to 8 carbon atoms or cyanoalkyl radicals having from 3 to 4 carbon atoms, at least 50% of all these radicals being methyl radicals, (B) 5 to 200 parts of filler, (C) 2 to 20 parts of polyalkoxylated organosilane of the formula: R'XSi[(oCH2CH2)poCH3]4-x in which the symbol R' represents a methyl, vinyl, allyl, methallyl or phenyl radical and the symbols p and x independently represent zero or one.

(D) 0.5 to 15 parts of a primary and secondary organic amine having a pKb not exceeding 5 in an aqueous medium and having a boiling point of at least 600C at atmospheric pressure, or an aminoorganosilane corresponding to the general formula: Ya'NH(G'X),GSi[(OCH2CH2)pOR11]3-mYRm in which the symbol R" represents a methyl or ethyl radical, the symbol G represents an alkylene radical having from 1 to 5 carbon atoms, the symbol X represents an oxygen or sulphur atom, the symbol G' represents an alkylene radical having from 2 to 5 carbon atoms, the symbol Y' represents a radical of the formula (G"NH)kR"', in which the symbol G" represents an alkylene radical having from 2 to 6 carbon atoms, the symbol R"' represents a hydrogen atom or an alkyl radical having from 1 to 4 carbon atoms and the symbol k represents zero, one, two or three, the symbol yv represents a methyl, vinyl or phenyl radical, the symbols p and y independently represent zero or one such that if p represents one, the symbol R" only represent a methyl radical, and the symbol m represents zero, one, two or three, and (E) 0.005 to 3 parts of hardening catalyst which is an iron chelate, tin, iron or lead salt of a.

carboxylic acid, organotin salt of carboxylic acid, a product resulting from the reaction of a said organotin salt with alkyl titanate, or a product resulting from the reaction of a diorganotin chloride with an alkyl ester of thioglycolic acid.

2. A composition according to Claim 1, in which the organosilane (C) is Si(OCH3)4, Si(OCH2CH2OCH3)4, CH2=CHSi(OCH3)3, CH2=CHSi(OCH2CH20CH3)3, C6H5Si(OCH3)3 or C6H5Si(OCH2CH2OCH3)3.

3. A composition according to Claim 1 or 2, in which component (D) is an organic amine of the formula: H2N(CH2),CH3, H2NCH2CH2CH(CH3)CH2C(CH3)2CH2NH2, H2N(CH2)3CH3, H2NCH2CH2NH2,

or an aminoorganosilane of the formulae: H2N(CH2)2NH(CH2)3Si(OCH3)3, H2N(CH2)2NH(CH2)3Si(OCH2CH2OCH3)3, H2N(CH2)3Si(OCH3)3, H2N(CH2)2NH(CH2)2NH(CH2)3Si(OCH3)3, H2N(CH2)30(CH2)3Si(OCH3)3, H2N(CH2)3O(CH2)3Si(OCH2CH2OCH3)3, or H2N(CH2)2S(CH2)3Si(OCH3)3.

4. A composition according to any one of Claims 1 to 3, in which a s bis-(triorganosiloxy)- diorganopolysiloxane polymer having a viscosity of at least 10 mPa.s at 250C, the organic radicals bonded to the silicon atoms being methyl, vinyl or phenyl radicals such that at least 60% are methyl radicals, is incorporated in an amount of at most 150 parts per 100 parts of the a,- dihydroxydiorganopolysiloxane polymers (A).

5. A composition according to any one of Claims 1 to 4 in which 3 to 15 parts of component (C) are used per 100 parts of component (A).

6. A composition according to Claim 1 substantially as described in any one of Examples 1 to 7.

7. A process for preparing a composition as claimed in any one of the preceding Claims which comprises mixing components (A) and (B) at a temperature of at least 700C at below atmospheric pressure and subsequently adding components (C), (D) and (E) in the absence of moisture.

8. A composition as defined in Claim 1, whenever prepared by a process as claimed in Claim 7.

9. An elastomer formed from a composition as claimed in any one of Claims 1 to 6 and 8.