FR2669341A1 - Polyorganosiloxane containing butadienyl residue(s), processes for its preparation and the compositions derived therefrom which can be crosslinked to an elastomer - Google Patents

Abstract

Linear or branched polyorganosiloxane containing butadienyl residue(s) exhibiting, per molecule, at least three siloxyl units, at least one unit of which corresponds to the formula: in which: X is a butadienyl residue of formula: R2R3C=CR1-HC=CH-(II) where each of R1, R2 and R3 denotes a hydrogen atom or an organic radical, R denotes a hydrocarbon radical containing from 1 to 12 carbon atoms, and a = 0, 1 or 2. The polyorganosiloxane according to the invention can be prepared by hydrosilylation from the corresponding polyhydroorganosiloxane on an ene-yne compound of formula R2R3C=CR1-C IDENTICAL CH (II'). The polydiorganosiloxanes according to the invention can be employed as base polymer in silicone compositions capable of being crosslinked to elastomer, in particular by exposure to atmospheric oxygen.

Description

POLVORGANOSILOXANE HAS (S) BUTADIENYLATED ITS METHODS OF
PREPARATION AND COMPOSITIONS YES DERIVED CROSSLINKED
IN ONE ELASTOMER
The present invention relates in particular to a polyorganosiloxane containing 1,3-butadiene and its methods of preparation, as well as compositions comprising, as base polymer, a polydiorganosiloxane of this type, stable in the absence of gaseous oxygen (in particular in the absence of the oxygen of the air) and crosslinkable to an elastomer, in particular by exposure at room temperature to oxygen in the air.

 Single-component silicone compositions (that is, in the form of a single package) capable of cross-linking to an elastomer by polycondensation reaction by exposure at room temperature to the humidity of the air are well known in the art. those skilled in the art and are described in numerous patent documents. In this context, a tin-based catalyst is generally used which can generate degradation reactions of the elastomer formed during the aging of the latter.

 Other compositions capable of crosslinking by exposure at ambient temperature to gaseous oxygen, in particular to oxygen in the air, and in the presence of a metal catalyst other than tin have already been described. These base polymers are either silicone oils with mercapto residues (see in particular US-A-4,252,932), or oils with a residue (s) comprising a pentadienylene-1,3 or -1,4-group ( cf.

US-A-4,256,954). These compositions are however not fully satisfactory. On one side (mercapto residues), the compositions may have the disadvantage of giving off unpleasant odors related to the presence of mercapto residue (s), while on the other side (pentadienylene group residues), it is the process for preparing the oils which may have certain drawbacks, because it appears that the attachment of each pentadienylene group residue on the silicone substrate is essentially either by hydrosilylation of an allylic compound comprising the group residue pentadienylene with a SiH group of the silicone substrate, and in this case it is possible to fear the development of undesirable side reactions concerning the allyl group, either by chemical coupling between a compound, comprising the pentadienylene group residue equipped with a second functional group; able to react with the first functional group and in this case the synthesis can be increased if the silicone substrate, having undergone a preliminary operation functionalization, is not directly available and needs to be synthesized.

 An object of the present invention is to provide a novel polyorganosiloxane, in this case a poly (1,3-butadiene) polyorganosiloxane which is capable of crosslinking at ambient temperature in the presence of gaseous oxygen and in the presence of a metal curing catalyst other than tin.

 Another object of the present invention is to provide processes for the preparation of polyorganosiloxane of the aforementioned type, at least one of which does not have the drawbacks mentioned above during the discussion of the prior art and consists in selective hydrosilylation. from a readily available polyhydrogenosiloxane on a conjugated ene-yne compound.

dans laquelle R1, R2 et R3, qui peuvent être identiques ou différents, représentent chacun un atome d'hydrogène ou un radical organique purement hydrocarboné ou comportant éventuellement un ou plusieurs hétéroatomes, avec la condition complémentaire selon laquelle le nombre total d'atomes de carbone du reste X est au plus égale à 40 ;; R R représente un radical hydrocarboné monovalent ayant de 1 à 12 atomes de carbone, éventuellement substitué par un ou plusieurs atomes d'halogène ou par un groupement -CN (les radicaux R, quand il y en a plusieurs, pouvant être identiques ou différents entre eux) a a est un nombre égal à 0,1 ou 2. These objects, as well as other objects, are achieved by the present invention which concerns more precisely in a first object, a polyorganosiloxane characterized in that it has per molecule at least three siloxyl units, at least one siloxyl unit responds to the general formula
XRaSiO3-a (I)
2 in which XX is a butadiene-1,3-yl residue essentially corresponding to the formula

in which R 1, R 2 and R 3, which may be identical or different, each represent a hydrogen atom or a purely hydrocarbon-based organic radical or optionally containing one or more heteroatoms, with the complementary condition according to which the total number of carbon atoms the remainder X is at most equal to 40 ;; RR represents a monovalent hydrocarbon radical having 1 to 12 carbon atoms, optionally substituted by one or more halogen atoms or by a -CN group (the R radicals, when there are several, which may be identical or different from one another; ) aa is a number equal to 0.1 or 2.

The polyorganosiloxane optionally further comprises other siloxyl motif (s) corresponding to the formula
RbSiO4-b (III)
2 in which RR has the same meaning as that given in relation to formula (I). b is a number equal to 0.1, 2 or 3.

 In the following, the term "lower alkyl radicals" will be used to denote linear or branched alkyl radicals containing from 1 to 4 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl and iso-butyl radicals. t-butyl. The term "lower alkoxy radicals" denotes linear or branched alkoxy radicals containing from 1 to 4 carbon atoms, such as methoxy, ethoxy, propoxy, isopropoxy or butoxy radicals. The term "lower alkenyl radicals" will be used to denote radicals containing from 2 to 4 carbon atoms, such as vinyl, propen-1-yl, allyl, isopropenyl, butene-3-yl, butene-2-yl, butene-1-yl, methyl- 1 propene-2-yl.

 According to a preferred definition (due), R is chosen from linear or branched alkyl radicals having from 1 to 12 carbon atoms, these radicals possibly being substituted by one or more chlorine, bromine or fluorine atoms or by a grouping -CN; a phenyl radical, optionally substituted with one or more lower alkyl and / or lower alkoxy radicals or with one or more chlorine atoms.

 According to a more preferred definition (d2), R is chosen from methyl, ethyl, propyl and phenyl radicals with the additional condition that at least 50% by number of the radicals R are methyls.

 The polyorganosiloxanes according to the invention may therefore represent a linear, cyclic or branched structure.

dans laquelle . les symboles R et X ont les significations données ci-avant à propos de la formule (I) . le symbole Y représente un radical monovalent choisi parmi les radicaux
X, R et hydroxyle . m est un nombre entier ou fractionnaire allant de 0 à 1 000 . n est un nombre entier ou fractionnaire allant de 0 à 100 avec la condition supplémentaire selon laquelle si n = 0, au moins un des deux radicaux Y représente le reste X p p est un nombre entier ou fractionnaire allant de O à 50 . la somme m + n + p est au moins égale à 1 ;;
* et ceux de formule moyenne

dans laquelle . les symboles R et X ont les significations données ci-avant à propos de la formule (I) . r est un nombre entier ou fractionnaire allant de O à 9 . s est un nombre entier ou fractionnaire allant de 1 à 10 . t est un nombre entier ou fractionnaire allant de O à 9 . la somme r + s + t est comprise entre 3 et 10 inclus.The present invention, taken in its first object, aims more precisely
random polydiorganosiloxane copolymers, block or block copolymers, of average formula

in which . the symbols R and X have the meanings given above with respect to the formula (I). the symbol Y represents a monovalent radical chosen from among the radicals
X, R and hydroxyl. m is an integer or fractional number ranging from 0 to 1000. n is an integer or fractional number ranging from 0 to 100 with the additional condition that if n = 0, at least one of the two radicals Y represents the residue X pp is an integer or fractional number ranging from 0 to 50. the sum m + n + p is at least 1 ;;
* and those of average formula

in which . the symbols R and X have the meanings given above with respect to the formula (I). r is an integer or fractional number ranging from 0 to 9. s is an integer or fractional number ranging from 1 to 10. t is an integer or fractional number ranging from 0 to 9. the sum r + s + t is between 3 and 10 inclusive.

Preferably, the polymers of formula (IV) are those for which (polymers called PL1): m is an integer or fractional number ranging from 2 to 800. n is an integer or fractional number ranging from 1 to 60 with the additional condition that if n = 1, then both radicals
Y represent the remainder X or if n = 2, at least one of the two radicals Y represents the remainder X. p is an integer or fractional number ranging from 0 to 10. R has the preferred definition (d1) given above with respect to formula (I). the remainder X has the preferential definition (d3) which will be given below.

More preferably, the polymers of formula (IV) are those for which (so-called PL2 polymers). m is an integer or fractional number ranging from 2 to 800. n is an integer or fractional number ranging from 1 to 60 with the additional condition that if n = 1, then both radicals
Y represent the remainder X or if n = 2, at least one of the two radicals Y represents the remainder X pp is an integer or fractional number ranging from 0 to 10. R has the more preferred definition (d2) given above with respect to formula (I); the remainder X has the more preferential definition (d4) which will be given below.

 Preferably, the polymers of formula (V) are those for which (polymers referred to as PC1): r is an integer or fractional number ranging from 0 to 3. s is an integer or fractional number ranging from 3 to 6 t is an integer or fractional number ranging from 0 to 3; . the sum r + s + t is between 3 and 6 R R has the preferred definition (d1) given above with respect to formula (I). the remainder X has the preferential definition (d3) which will be given below.

 More preferably, the polymers of formula (V) are those for which (polymers known as PC2): r is an integer or fractional number ranging from 0 to 3. s is a whole or fractional number ranging from 3 to 6. t is an integer or fractional number ranging from 0 to 3; . the sum r + s + t is between 3 and 6 inclusive. R has the more preferred definition (d2) given above with respect to formula (I). the remainder X has the more preferential definition (d4) which will be given below.

With regard to the butadienyl radical X essentially corresponding to the formula R2R3C = CR1-HC = CH- (II), the various radicals R1, R2 and R3 have the following meanings
R1 symbolizes, in addition to a hydrogen atom a) - an alkyl radical, linear or branched, having from 1 to 8 atoms of
carbon b) - a lower alkoxy radical c) - a linear or branched alkenyl radical containing from 2 to 8 atoms
of carbon and from 1 to 2 ethylenic double bonds, conjugated or otherwise,
optionally substituted with 1 to 3 lower alkoxy radicals d) - an aryl radical having 1 or 2 fused benzene rings,
optionally substituted with 1 to 3 alkyl or alkoxy radicals
lower e) - an arylalkyl radical having 1 to 2 carbon atoms in the
alkyl residue and 1 or 2 benzene rings condensed or not in the
aryl residue f) - a 5- or 6-membered heterocyclic radical having a
heteroatom such as sulfur, oxygen or nitrogen, bearing
optionally 1 or 2 ethylenic double bonds, and substituted
optionally with 1 or 2 lower alkyl or alkoxy radicals;
- R2, R3, identical or different, represent in addition to a hydrogen atom a) - linear or branched alkyl radicals, comprising from 1 to
20 carbon atoms, optionally substituted with alkoxy radicals
lower, by cycloalkyl or cycloalkenyl radicals comprising
from 5 to 8 carbon atoms (possibly bearing 1 or 2 doubles
ethylenic bonds and optionally substituted with 1 to 3 radicals
alkyls, alkoxy, or lower alkenyls), by radicals
5- or 6-membered heterocyclic compounds having a heteroatom such as
sulfur, oxygen or nitrogen (possibly carrying 1 or 2 doubles
ethylene bonds) b) - lower alkoxy radicals c) - linear or branched alkenyl radicals having from 2 to
12 carbon atoms and from 1 to 3 ethylenic double bonds,
conjugated or not, optionally substituted with alkoxy radicals
lower, cycloalkyl, cycloalkenyl, heterocyclic radicals
such as those defined in (a) (d) - cycloalkyl or cycloalkenyl radicals having from 5 to
8 carbon atoms, and optionally 1 or 2 double bonds
ethylenic, optionally substituted with 1 to 3 alkyl radicals,
alkoxy or lower alkenyls e) - cycloalkenylideneall radicals containing a radical
cycloalkenyl such as those defined under (a) and an alkyl radical having
1 to 3 carbon atoms f) - aryl radicals having 1 or 2 fused benzene rings or
no, optionally substituted with 1 to 3 alkyl, alkoxy or
lower alkenyls g) - arylalkyl radicals having from 1 to 5 carbon atoms in
the alkyl radical and 1 or 2 fused benzene nuclei or not (the
the benzene rings can optionally be substituted with 1 to
3 alkyl, alkoxy or lower alkenyl radicals) h) - 5- or 6-membered heterocyclic radicals, having a
heteroatom such as sulfur, oxygen or nitrogen, bearing
optionally 1 or 2 ethylenic double bonds, and if appropriate
substituted with 1 or 2 alkyl or lower alkoxy radicals; i) - a -COOH group
R2 or R3 can form with R1 and the carbon atoms to which these various radicals are bonded an aliphatic hydrocarbon ring comprising from 5 to 7 carbon atoms and 1 or 2 ethylenic double bonds (optionally substituted with 1 to 3 alkyl, alkenyl or lower alkoxy), two of the radicals R 2 or R 3 and R 3 together forming a divalent alkylene or alkenylene radical having from 3 to 5 carbon atoms, optionally substituted by 1 to 3 lower alkyl, alkenyl or alkoxy radicals;
- R2 or R3 can also form with R1 and the carbon atoms to which they are bonded, a 5- or 6-membered heterocycle (having 1 or 2 ethylenic double bonds and optionally substituted with 1 to 3 lower alkyl or alkoxy radicals) by the intermediate of a heteroatom taken from the group formed by nitrogen (optionally substituted by a lower alkyl radical), oxygen and sulfur (the radicals R2 or R3 then forming with the radical R1 a divalent radical containing a terminal heteroatom or not, and if necessary an ethylenic double bond)
- R2 or R3 can form together with R1 and the carbon atoms to which they are bonded, an arylcycloalkenyl ortho-condensed polycyclic system containing from 5 to 7 carbon atoms and 1 or 2 ethylenic double bonds in the alkenyl radical, and 1 or 2 benzenic rings condensed or not in the aryl residue (the benzene ring or nuclei possibly being substituted by 1 to 3 lower alkyl or alkoxy radicals)
R2 and R3 may together form, with the carbon atom to which they are bonded, an aliphatic hydrocarbon ring such as that previously defined for R2 or R3 with R1, R2 and R3 together forming a divalent alkylene or alkenylene radical having from 4 to 6 carbon atoms, optionally substituted with 1 to 3 lower alkyls.

According to a preferred definition (d3)
R1 represents a hydrogen atom or a radical chosen from among the radicals: methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, n-hexyl; methoxy, ethoxy, propoxy, isopropoxy, butoxy; vinyl, propen-1-yl, allyl, isopropenyl, 1-methyl-2-propenyl, 1-buten-1-yl, 2-butenyl, 3-butenyl, 3-pentenyl, 4-methylpenten-3-yl; 1,4-dimethylpenten-3-yl; phenyl, tolyl; benzyl furyl-2, furyl-3
R2 represents a hydrogen atom or a radical chosen from among the radicals: methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, n-hexyl; methoxy, ethoxy, propoxy, isopropoxy, butoxy
- R3 represents a hydrogen atom or a radical selected from among the radicals: methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, n-hexyl; methoxy, ethoxy, propoxy, isopropoxy, butoxy; vinyl, propen-1-yl, allyl, isopropenyl, 1-methyl-2-propenyl, 1-buten-1-yl, 2-butenyl, 3-butenyl, 3-pentenyl, 4-methylpenten-3-yl; 1,4-dimethylpenten-3-yl; phenyl, tolyl; benzyl furyl-2, furyl-3; and the radical of formula

- or R3 forms with R1 and the carbon atoms to which they are attached the following divalent radicals: trimethylene, tetramethylene, methyl-2 propylene or the radicals of formulas

 or R3 forms, with R2 and with the carbon atom to which they are bonded, the tetramethylene, pentamethylene or hexamethylene radicals.

According to a more preferential definition (d4), the symbols R1,
R2 and R3 have the following meanings
R2: a hydrogen atom,
- R3 and R1: they together together with the carbon atoms to which they are attached divalent radicals selected from trimethylene radicals, tetramethylene and those of formulas (A), (B), (C) and (D).

 There are several processes making it possible to obtain the polymers with units of formulas (I) + optionally (III) (denominated in the following: polymers of formula (I + optionally III)) and the polymers of formulas (IV) and (V ).

 A first advantageous method, and this constitutes a second object of the present invention, consists in the hydrosilylation of a conjugated ene-yne type compound made from a polymer corresponding to those of formulas (I + optionally III), (IV) and (V) in which all X residues are hydrogen atoms (so-called SiH polymer).

dans laquelle R1, R2 et R3 ont les significations générales ou préférentielles données ci-avant pour la formule (II). The present invention thus aims, in a second object, a process for the preparation of polyorganosiloxane having, per molecule, at least three siloxyl units, at least one siloxyl unit of which corresponds to formula (I), characterized in that a reaction of at least partial hydrosilylation in the presence of a catalytically effective amount of a platinum catalyst of a polyorganosiloxane having, per molecule, at least three siloxyl units, at least one siloxyl unit of which corresponds to the formula
HRaSiO3 a (I ')
2 in which the symbols R and a have the general or preferential meanings given above for formula (I), on a conjugated ene-yne type compound chosi of those of formula

wherein R 1, R 2 and R 3 have the general or preferred meanings given above for the formula (II).

dans laquelle
les symboles R et m ont les significations générales ou préférentielles données ci-avant pour la formule (IV)
. q est un nombre entier ou fractionnaire égal à n + p
la somme m + q est au moins égale à 1
. le symbole Z représente R, un hydroxyle ou un atome d'hydrogène * et de formule

dans laquelle
les symboles R et r ont les significations générales ou préférentielles données ci-avant pour la formule (V)
. u est un nombre entier ou fractionnaire égal à s + t
. la somme r + u est comprise entre 3 et 10 inclus.The polydiorganosiloxanes of formulas (IV) and (V) are respectively prepared by the same method, the starting polydiorganosiloxane being chosen from those of formula

in which
the symbols R and m have the general or preferential meanings given above for the formula (IV)
. q is an integer or fractional number equal to n + p
the sum m + q is at least equal to 1
. the symbol Z represents R, a hydroxyl or a hydrogen atom * and of formula

in which
the symbols R and r have the general or preferential meanings given above for the formula (V)
. u is an integer or fractional number equal to s + t
. the sum r + u is between 3 and 10 inclusive.

 With regard to the symbol q of the formula (IV '), the following is recalled: case of the preparation of a polymer of formula (IV) taken in its general definition: if q = 0, then at least one of the two radicals Z represents a hydrogen atom and m is at least equal to 1-case of the preparation of a polymer of formula (IV) taken in its preferred form (PLI) or more preferential (PL2): if q = 1, then the two radicals Z represent a hydrogen atom or if q = 2, at least one of the two radicals Z represents a hydrogen atom.

By the expression "1,3-buradiene-residue corresponding essentially to the formula (II)" which appears above on page 2, it is meant that the hydrosilylation reaction of which we have just spoken can lead to a polyorganosiloxane functionalized in the structure of which - in addition to the 1,3-butadiene residue (s) of formula (II) is present - a minor proportion of 1,3-butadiene residue (s) of formula

 The radicals of formula (II "), when it is formed, are in an amount at most equal to 5% relative to the total number of residues (II) + (II") present per molecule of polyorganosiloxane.

Among the compounds of the ene-conjugated ene type of formula (II '), there may be mentioned, among those preferably used, the compounds of formulas

 The compounds of formula (II ') which are used more preferably are chosen from compounds of formulas (Q), (R), (S), (T) and (U).

The en-yene compounds of formula (II ') can be synthesized from accessible raw materials using methods known from the prior art. These compounds are known as platinum inhibitors (see US-A-4,465,818). For example, they can be synthesized by dehydration of the corresponding acetylenic alcohols; the following reaction illustrates a similar way of synthesis

<tb><SEP> OH
<tb> MÛ <SEP> = <SEP> I <SEP> CH <SEP> Pyridine <SEP> O <SEP> r <SEP> C <SEP> CH
<Tb>
The platinum catalysts used to carry out the hydrosilylation reaction of the polymer of formula (I '), (IV'), or (V ') on the ene-yne compound of formula (II') are amply described in the literature; mention may in particular be made of the complexes of platinum and of an organic product described in US Patents US-A-3 159 601,
US-A-3 159 602, US-A-3,220,972 and European Patents EP-A-57,459,
EP-A-188 978 and EP-A-190 530 and the complexes of platinum and vinyl organopolysiloxane, described in US patents
US-A-3,419,593, US-A-3,715,334, US-A-3,377,432 and US-A-3,814,730 (IV ').

 In order to react the SiH polymer of formulas (I ') or (V') with the ene-yne compound, an amount of platinum catalyst calculated as the weight of platinum metal of 1 to 600 ppm is preferably used, preferably between 6 and 200 ppm based on the weight of SiH polymer.

 The hydrosilylation reaction may take place in bulk or in a volatile organic solvent such as toluene, heptane, xylene, tetrahydrofuran and tetrachlorethylene.

 It is generally desirable to heat the reaction mixture to a temperature of 100 to 150 ° C for the time required for the reaction to be complete. solution in an organic solvent, although it is possible to add drop by drop the ene-yne compound optionally in solution on the SiH polymer.

 The degree of progress of the reaction is checked by assaying the residual SiH groups with alcoholic potassium hydroxide and then the solvent is removed for example by distillation under reduced pressure.

 The crude oil of formulas (I + optionally III), (IV) or (V) may be purified, for example by passing through an absorbent silica column.

 Another process for preparing the polyorganosiloxanes of formulas (I + optionally III), (IV) with p = O and (V) with t = O, and this constitutes a third object of the present invention, consists in carrying out the hydrolysis and the polycondensation of a butadienyl-containing hydrolyzable silane or a mixture of silanes comprising at least one butadienyl-containing hydrolyzable silane.

ou d'un mélange de silanes hydrolysables comprenant au moins un silane de formule (VI), formule dans laquelle
les symboles R et X ont les significations générales ou préférentielles données ci-avant pour la formule (I) c c est égal à 1 ou 2
le symbole W représente un groupe alkoxy inférieur, de préférence méthoxy ou éthoxy, ou un atome d'halogène, de préférence un atome de chlore en opérant en présence éventuellement d'un halogénosiloxane, de préférence un chlorosilane de formule
RdCleSi (VII) avec d = 0,1, 2 ou 3, e = 0,1, 2, 3 ou 4 et d + e =
L'utilisation de chlorosilane de formule (VII) permet d'incorporer dans le polyorganosiloxane de formule (I), des motifs de formule (III). La polycondensation peut être arrêtée par simple neutralisation du milieu réactionnel.The present invention thus aims, in its third object, a process for the preparation of polyorganosiloxane having, per molecule, at least three siloxyl units, at least one siloxyl unit of which corresponds to formula (I), characterized in that the hydrolysis is carried out and the polycondensation of a hydrolysable silane of formula

or a mixture of hydrolysable silanes comprising at least one silane of formula (VI), in which formula
the symbols R and X have the general or preferential meanings given above for the formula (I) cc is equal to 1 or 2
the symbol W represents a lower alkoxy group, preferably methoxy or ethoxy, or a halogen atom, preferably a chlorine atom, operating in the presence optionally of a halosiloxane, preferably a chlorosilane of formula
RdCleSi (VII) with d = 0,1, 2 or 3, e = 0,1, 2, 3 or 4 and d + e =
The use of chlorosilane of formula (VII) makes it possible to incorporate in the polyorganosiloxane of formula (I), units of formula (III). The polycondensation can be stopped by simple neutralization of the reaction medium.

 In the case where it is desired to obtain linear polymers of formula (IV) and / or cyclic of formula (V), hydrolysis and polycondense for example dichlorosilane RCl2SiX with optionally dichlorosilane of formula R2Cl2Si.

In the case where the polycondensation is stopped by simple neutralization a reaction mixture is obtained comprising polymers of formula (IV) blocked at each of their ends by a hydroxyl group or by the unit
R2XSiOo, s if one additionally uses the silane R2ClSiX.

The polycondensation can also be stopped by adding, at the end of the reaction, an organosilicon compound capable of reacting with the terminal hydroxyls of the polymer of formula (IV) formed, this organosilicon compound being able to meet the formulas
R3SiCl, R3SiNHSiR3 and R3SiOSiR3
The duration of the hydrolysis can be between a few seconds and several hours.

 After hydrolysis, the aqueous phase is separated from the siloxane phase by any appropriate physical means, generally by decantation and extraction with an organic solvent such as isopropyl ether.

 The siloxane phase may be subsequently washed with water and then optionally distilled to separate the linear polymers of formula (IV) from the cyclic polymers of formula (V).

 The polymers of formula (IV) may also be prepared, and this constitutes a variant of the third subject of the present invention, by a method of equilibration between a polydiorganopolysiloxane corresponding to formula (IV) where X is R and Y is OH, with a silane of formula (VI).

dans laquelle les symboles W, R et c ont les significations générales ou préférentielles données ci-avant pour la formule (VI), - sur le composé ène-yne de formule (II') qui a été définie ci-avant.The silanes of formula (VI) are compounds which can be easily synthesized by the method consisting in producing, in a manner known per se, the hydrosilylation of hydrogenosilane of formula

in which the symbols W, R and c have the general or preferential meanings given above for the formula (VI), on the ene-yene compound of formula (II ') which has been defined above.

(dans ce cas R2 = H et R3 forme avec
R1 un radical divalent triméthylène) sont des produits connus ; cf. en particulier Chemical Abstracts : 57 ; 16647 (1962) et 61, 16088 (1964).The silanes of formula (IV) in which the butadienyl residue X is a residue of formula H 2 C = CH - CH = CH - (in this case: R 1 = R 2 = R 3 =
H) or formula

(in this case R2 = H and R3 form with
R1 a divalent trimethylene radical) are known products; cf. in particular Chemical Abstracts: 57; 16647 (1962) and 61, 16088 (1964).

The other silanes of formula (VI), that is to say those in the formula of which the residue X has the meanings given for formula (II), excluding the case where R1 = R2 = R3 = H and R2 = H with R3 + R1 = -CH2-CH2-CH2- are products which, to the knowledge of the
Applicant, are new.

 Silanes of formula (VI) have multiple uses.

 They can be used to prepare the polyorganosiloxanes of formulas (I), (IV) and (V) above.

 They can also be used as coupling agents and as enzyming agents.

 They can be used as crosslinking agents in organopolysiloxane compositions which can be cold-crosslinked as elastomers and as adhesion promoters.

 They can more particularly be used as accelerating agents for crosslinking with oxygen and with the humidity of the air of conventional acrylic latexes used as paints and coatings, with a content of 0.1 to 10% by weight of silanes of formula ( VI) relative to the weight of monomers, acrylate monomers present in the latex.

 The branched polymers of formula (I) can be used to form hard coatings after crosslinking at room temperature with oxygen in the presence of a curing catalyst which is a salt or a complex of a metal.

 The polymers of formulas (IV) and (V), taken in their preferential (PL1 and PC1) or more preferential (PL2 and PC2) forms, are more particularly useful as basic polydiorganosiloxane polymers, within a silicone composition which is crosslinkable to an elastomer, in particular by exposure at ambient temperature to oxygen in the air.

The present invention thus relates, in a fourth object, to a polyorganosiloxane composition stable in storage in the absence of gaseous oxygen and crosslinkable to an elastomer, in particular by exposure at ambient temperature to oxygen in the air, characterized in that it includes
(1) - 100 parts of at least one polydiorganosiloxane chosen from the polymers of formulas (IV) and (V) taken in their (preferred) forms PL1 and PC1 which have been defined above,
(2) - a catalytically effective amount of a metal curing catalyst,
(3) - 0 to 250 parts of at least one mineral filler.

 Component (1) of the composition is preferably chosen from polymers of formulas (IV) and (V) taken in their (more preferred) forms PL2 and PC2 which have also been defined above.

As a catalyst (2) for curing, the monocarboxylic acid salts of metals such as barium, bismuth, calcium, cerium, cobalt, chromium, copper, iron, lead, magnesium, manganese, nickel, rare earths, zinc and zirconium. Other organic ligands can be linked to metals such as chelated ligands (acetylacetonate) and carbonyl. The catalysts recommended are the monocarboxylic acid salts of cobalt, iron, manganese and more particularly cobalt ethyl-2 hexanoate.

 By the term "catalytically effective amount of catalyst" (2) is meant an amount sufficient to ensure proper crosslinking. Amounts of 0.01 to 5 parts, preferably 0.1 to 3 parts by weight of metal salt per 100 parts of polymer (1), are generally suitable.

 The composition may further comprise a drying agent chosen, for example, from alkali metal and alkaline earth metal oxides.

 It is recommended to add 0.1 to 5 parts of drying agents per 100 parts of oil (1).

 It is also recommended to add, in order to reduce the setting time, a redox agent of the iron oxide type, copper sulphate, etc.

for example at the dose of 0.1 to 3 parts per 100 parts of oil (1).

 The mineral fillers (3) are used in an amount of from 0 to 250 parts, preferably from 20 to 200 parts, per 100 parts of polymer (1).

 These fillers may also be in the form of more coarsely divided products having an average particle diameter greater than 0.1 micron. Examples of such fillers include ground quartz, diatomaceous earth silicas, calcium carbonate, calcined clay, rutile titanium oxide, iron, zinc, chromium and zirconium oxides. , magnesium, the various forms of alumina (hydrated or not), boron nitride, lithopone, barium metaborate, barium sulfate, glass microbeads their specific surface area is generally less than 30 m 2 / g.

These fillers (3) may have been surface-modified by treatment with the various organosilicon compounds usually employed for this purpose. Thus these organosilicon compounds may be organochlorosilanes, diorganocyclopolysiloxanes, hexaorganodisiloxanes, hexaorganodisilazanes or diorganocyclopo lysiloxanes (French patents FR-A-1 126 884, FR-A-1 136 885,
FR-A-1,236,505; British Patent GB-A-1,247,234). The treated fillers contain, in most cases, from 3 to 30% of their weight of organosilicic compounds.

 The charges (3) may consist of a mixture of several types of charges of different particle size; for example, they may consist of 5 to 95% of finely divided silicas with a BET specific surface area greater than 40 m 2 / g and 95 to 5% of more coarsely divided silicas with a specific surface area of less than 30 m 2 / g or treated or untreated calcium carbonate.

dans laquelle . R' est choisi parmi les radicaux alkyles, linéaires ou ramifiés, ayant de 1 à 12 atomes de carbone et un radical phényle éventuellement substitué par un ou plusieurs radicaux alkyles inférieurs ; de préférence, R' est méthyle et/ou phényle v v est un nombre entier ou fractionnaire choisi de telle sorte que le polymère de formule (IX) présente une viscosité à 25 "C inférieure à 100 000mPa.s, de préférence allant de 50 à 10 000 mPa.s.According to an advantageous variant, it is possible to incorporate in addition to the elastomer composition a diorganopolysiloxane oil (4) which is not reactive in the composition of formula

in which . R 'is selected from alkyl radicals, linear or branched, having 1 to 12 carbon atoms and a phenyl radical optionally substituted by one or more lower alkyl radicals; preferably, R 'is methyl and / or phenyl vv is an integer or fractional number chosen such that the polymer of formula (IX) has a viscosity at 25 ° C of less than 100 000mPa.s, preferably ranging from 50 to 10,000 mPa.s.

 When using an oil (4) of formula (IX), the amount used is 1 to 30 parts of oil per 100 parts of oil (1).

 According to another advantageous variant, an adhesion promoter (5) may be added in a proportion of from 0 to 20 parts, preferably from 0.2 to 10 parts, per 100 parts of the oil (1).

This agent is chosen from organosilicon compounds bearing both organic groups substituted by radicals chosen from the group of amino, ureido, isocyanato, epoxy, alkenyl, isocyanurate, hydantoid and mercaptoester radicals. hydrolysable groups bonded to silicon atoms. By way of illustration, mention may be made of organosilicon compounds corresponding to the following formulas

NH2CH2CH2NHCH2CH (CH3) COO (CH2) 3 Si (0CH3) 3
(C2H5o) 3Si (CH2) 3NH2
(CH30) 3Si (CH2) 3NHCH2CH2NH2
The compositions according to the invention may also contain the usual adjuvants or additives, usually used in silicone elastomer compositions, which are well known to those skilled in the art.

Among these adjuvants, mention may be made in particular of organic plasticizers. The plasticizers described in the US patent
US-A-4,525,565 are particularly useful.

 Other adjuvants or additives that may be mentioned in particular are coloring pigments, thermal stabilizers, antioxidants, fluidizing agents, thixotropic agents, antioxidants, thermal stabilizers, perfumes, etc.

 In order to manufacture the compositions in accordance with the invention, it is necessary to use an apparatus which makes it possible to intimately mix, in the absence of gaseous oxygen and preferably without the addition of heat, the various basic constituents to which adjuvants are optionally added. and the aforementioned additives.

 A more particularly recommended method is that of introducing into a mixer, at room temperature, away from oxygen from the air, the ingredients in the following order: the oil (1), optionally the oil (4), optionally the plasticizer, the catalyst (2), then optionally the drying agent and finally the filler (3) with possibly the adhesion promoter (5).

 Then degassing is preferably carried out under reduced pressure, for example between 0.01 and 10 KPa.

 The compositions according to the invention are storage stable, in the absence of gaseous oxygen, for at least 6 months and even a year, and are more particularly suitable for grouting in the building industry, the assembly of the most suitable materials. various (metals, plastics, natural and synthetic rubbers, wood, cardboard, earthenware, brick, ceramics, glass, stone, concrete, masonry), insulation of electrical conductors, encapsulation of electronic circuits, preparation of molds for the manufacture of objects made of resins or synthetic foams.

The compositions according to the invention may optionally be used after dilution in liquid organic compounds, the diluents are preferably commercially available products chosen from
aliphatic, cycloaliphatic and aromatic hydrocarbons,
halogenated or not, such as cyclohexane and toluene,
aliphatic and cycloaliphatic ketones, such as methyl ethyl ketone,
esters, such as ethyl acetate.

 The amount of diluent generally remains small, it is generally less than 50% by weight relative to the total weight of the composition.

 The aforementioned dilutions of these compositions in organic diluents are especially suitable for the impregnation in thin layers of woven or non-woven articles, the coating of sheets of metal or of plastic or cellulosic material; however they can be projected, for example by spraying with a paint gun, on any substrates, for which it is necessary to obtain a coating with a thickness of the order of 5 to 300 μm. . After the dilution is projected, the diluents evaporate and the released compositions cure to a perfectly uniform rubbery film.

 Furthermore, this elastomer film can serve as an inert, non-toxic, anti-adhesive coating for various substrates in contact with food products such as (i) confectionery wrappers, or frozen meats, (2i) metal trays useful for the preparation of ice creams and sorbets and (3i) metal nets in which the bread dough is deposited and molded and which is introduced with their contents into the ovens for baking bread. It can also be used as non-stick and nontoxic coating of materials in contact with the human body such as compresses, special dressings for burns.

 It should be noted that the compositions according to the invention are capable of crosslinking in elastomer either by exposure of the silicone composition to heat or by exposure of the composition to ultraviolet radiation.

 In the following or the preceding, unless expressly stated otherwise, parts and percentages are by weight.

 The following examples illustrate the invention.

 In the formulas of these examples Me symbolizes a methyl radical.

The mechanical properties of the elastomer compositions stored in an airtight aluminum oxygen tube are evaluated as follows
The contents of a tube are spread in the form of a thin layer, in the open air, on a support plate.

 The time (tp) of skin formation on the surface of the film is measured and the time (tnc) for obtaining a non-tacky feel and the demolding time (td) necessary to be able to remove the elastomer from the plate. .

The deposited layer is transformed into a rubbery film; the elastomer film is removed as soon as it is demoldable and measures, after aging for x days at room temperature, the dynamometric properties of the elastomers, namely
the hardness SHORE A (DSA) according to standard NF-T-51 109) after
- the breaking strength (R / R) in MPa according to the) aging
standard NF-T-46 002) of
- the elongation at break (A / R) in% according to the) x
standard NF-T-46 002) days
the modulus (M) in MPa for an elongation of 100%). EXAMPLE 1 Preparation of a Butadiene Residue Oil
In a glass reactor (three-neck) of capacity 500 cc, equipped with a condenser, a central stirring blade connected to a motor, a temperature probe, 7.64 g of ethynylcyclohexene (formula (Q) given above) either 0.072 mole and 0.018 g of a 12.4% solution of platinum (0.000011 at g of Pt) in hexane of a catalyst as described in US Pat. US-A-3,220,972.

The mixture is brought to 70 ° C. for 20 minutes and 225 g of a polymethylhydrogen dimethylsiloxane α, d-dimethylhydrogen oil having 0.032% by mass of hydrogen of the formula are introduced by means of a dropping funnel. average

 The duration of introduction of the oil is 10 minutes during which no rise in temperature is observed. The conversion rate of the SiH functions is 9% after 3 hours. The mixture is then heated to 120 ° C. and this temperature is maintained for 120 minutes.

 The heating is then stopped and allowed to return to room temperature.

 230 g of oil are then taken, which is then analyzed.

 The determination of the hydrogeno units indicates that there is no more hydrogen bonded to silicon, the infrared analysis confirms this observation.

This analysis is completed by a spectroscopic study
NMR29Si and 1H showing that only the triple bond was hydrosilylated.

dans laquelle

- EXEMPLE 2 - Réticulation à l'oxygène de l'air
Une composition type est mise en oeuvre en mélangeant sous azote
- 100 parties de l'huile (HU - 1) obtenue à l'exemple 1,
- 10 parties d'huile polydiméthylsiloxane (PDMS)
a,-triméthylsilyle de viscosité 100 MPa.s,
- 1 partie d'éthyl-2 hexanoate de cobalt à 6 % de cobalt,
- 100 parties de carbonate de calcium, et
- 8 parties de silice de combustion A150, de surface
spécifique 150 m2/g.An oil (HU - 1) of average formula is obtained

in which

EXAMPLE 2 Crosslinking with oxygen in the air
A typical composition is used by mixing under nitrogen
100 parts of the oil (HU - 1) obtained in Example 1,
10 parts of polydimethylsiloxane oil (PDMS)
α, -trimethylsilyl of viscosity 100 MPa.s,
1 part of 2-ethyl cobalt hexanoate with 6% cobalt,
- 100 parts of calcium carbonate, and
- 8 parts of combustion silica A150, surface
specific 150 m2 / g.

 The mixture is kneaded to a homogeneous non-flowable paste which is then stored in a 250 cc airtight oxygen cartridge.

 After 48 hours of storage at 20 ° C the product is extruded and from 20 g of mixture a 260 μm film is produced on a stainless steel plate covered with a 60 × 60 mm polyester sheet.

It is then allowed to crosslink with the oxygen of the air and the following properties are obtained:
tp: 10 minutes,
tnc: 2 hours,
td: 24 hours,
DSA - 7 days: 30,
R / R - 7 days: 1 MPa,
A / R - 7 days: 120%.

EXAMPLE 3 Preparation of a Butadiene Residue Oil
In a glass reactor (three-neck) 250 cc capacity, equipped with a condenser, a central stirring plate connected to a motor, a temperature probe, was introduced 50 g of an oil of medium formula

 This oil is then heated with stirring and nitrogen atmosphere to a temperature of 105 ° C.

 A freshly prepared solution of ethynylcycloheene (9.02 g, 0.085 mol) containing 0.004 g of platinum in the form of a Pt / (divinyltetramethyldisiloxane) 2 complex (Pt / (DVTMS) 2) is then introduced in 1 minute. in solution in hexane at 12.4% platinum as described in US Pat. No. 3,814,730. The temperature then increases to reach 135 ° C. after 3 minutes.

 The mixture is then allowed to react for 1 hour with a heating bath temperature of 105 ° C. After 1 hour, all of the SiH units have been consumed (H2 release assay).

dans laquelle

la structure indiqué est confirmée par l'étude spectroscopique R.M.N29Si et 1H. An oil (HU - 3) of average formula is obtained

in which

the indicated structure is confirmed by the NMR29Si and 1H spectroscopic study.

EXAMPLE 4 Preparation of a Butadiene Residue Oil
In a 2000 cc glass reactor equipped with a three-blast stirring system, a mixture is introduced based on 13 g of ethynylcyclohexene and 0.120 g of a 12.4% Pt / (DVTMS) 2 complex. platinum, dissolved in hexane. The reaction mixture is brought to 50 ° C. and then 750 g of an oil of average formula are run in over 15 minutes.

 The reaction mixture is then heated to 116 ° C. and allowed to react for 90 minutes After 1 hour 30 minutes, the residual SiH units are zero: the reaction is quantitative.

 To eliminate any traces of residual monomer, the oil obtained is devolatilized under 1 mmHg for 2 hours at 90 ° C. after addition of 100 cc of cyclohexane to better entrain the residual monomer.

dans laquelle

- EXEMPLE 5 - Réticulation à l'oxygène de l'air
Pour tester l'aptitude à la réticulation de l'huile (HU - 4) obtenue à l'exemple 4, on mélange 100 parties de cette huile à une partie d'éthyl-2 hexanoate de cobalt à 6 % de cobalt.The oil obtained (HU - 4) is stored under nitrogen. Its viscosity is 40.103 MPa.s at 20 ° C. Its average formula is as follows

in which

EXAMPLE 5 Crosslinking with oxygen in the air
To test the crosslinking ability of the oil (HU-4) obtained in Example 4, 100 parts of this oil are mixed with a portion of cobalt ethyl 2-hexanoate at 6% cobalt.

 The mixture is then crosslinked in the open air in the form of a 2 mm thick film deposited on a polyethylene plate.

The following properties are obtained
- tp: 1 hour,
- tnc: 5 hours,
- td: 48 hours,
- R / R - 7 days: 0.2 MPa,
- A / R - 7 days: 166%,
- M - 7 days: 0.2 MPa.

sous atmosphère inerte.EXAMPLE 6 Preparation of a Butadiene Residue Oil
In a flat-bottomed reactor with a capacity of 2 liters and equipped with a three-blast stirring system, 800 g of hydrogenated silicone oil of average formula are introduced.

under an inert atmosphere.

 The temperature is brought to 105 ° C. with stirring and nitrogen, then a mixture based on 19 g of ethynylcyclohexene and 0.070 g of Pt / (DVTMS) 2 complex dissolved in hexane at 11 is poured in 8 minutes. 5% platinum.

 At the end of the casting, the temperature increases to reach 122 ° C. after 27 minutes of reaction.

dans laquelle

- EXEMPLE 7
Des compositions élastomère réticulant à l'oxygène de l'air sont élaborées à l'abri de l'oxygène en mélangeant à température ambiante (20 "C), dans un réacteur à fond plat de 2 litres de capacité, muni d'un système d'agitation tripales, les ingrédients suivants

After 1 hour and 20 minutes, the reaction is stopped by returning to ambient temperature; the determination of SiH functions shows that all of these groups have reacted. The resulting oil (HU - 6) has the average formula

in which

EXAMPLE 7
Air-oxygen-crosslinking elastomeric compositions are prepared in the absence of oxygen by mixing at room temperature (20 ° C.) in a flat-bottomed reactor of 2 liters capacity, equipped with a system three-dimensional agitation, the following ingredients

<tb><SEP> Example <SEP> 7-A <SEP> Example <SEP> 7-B
<tb> Oil <SEP> (HU <SEP> - <SEP> 6) <SEP> from <SEP> example <SEP> 6 <SEP> (parts) <SEP> 100 <SEP> 100
<tb> Oil <SEP> PDMS <SEP> α, -trimethylsilyl <SEP> (parts) <SEP> 10 <SEP> 10
<tb> Ethyl-2 <SEP> hexanoate <SEP> from <SEP> cobalt <SEP> to <SEP> 6 <SEP>% <SEP> from <SEP> Co <SEP> 1 <SEP> 1
<tb><SEP> (parts)
<tb> CaC03 <SEP> (parts) <SEP> 100 <SEP> 100
<tb> TiO2 <SEP> (parts) <SEP> 0 <SEP> 10
<tb> (CH3O) 3Si (CH2) 30CH2-CH-CH2 <SEP> (Parts) <SEP> 0 <SEP> 2
<tb><SEP> O
<tb> Silica <SEP> of <SEP> combustion <SEP> A150 <SEP> (parts) <SEP> 9 <SEP> 9
<Tb>
These compositions are placed in an aluminum tube and allowed to stand for 72 hours in the absence of oxygen from the air.

The compositions are then extruded in the form of 2 mm thick films and the dynamometric properties of the elastomers are measured.
Example 7-A Example 7-B tp (minutes) 15 tnc (hours) 6 7 td (hours) 33 48
DSA - 48 hours Top / Bottom 15/9 8/0
DSA - 7 days Top / Bottom 22/22 22/22
R / R - 7 days (MPa) 1 1.1
Return trip - 7 days 308 + 20 304 + 20
M - 7 days 0.5 0.6

Claims (3)

 XRaSiO3-a (I)  1. - Polyorganosiloxane characterized in that it has per molecule at least three siloxyl units, at least one siloxyl unit meets the general formula  in which R 1, R 2 and R 3, which may be identical or different, each represent a hydrogen atom or a purely hydrocarbon-based organic radical or optionally containing one or more heteroatoms, with the complementary condition according to which the total number of carbon atoms the rest X is at most equal to 40. R represents a monovalent hydrocarbon radical having 1 to 12 carbon atoms, optionally substituted by one or more halogen atoms or by a -CN group (the R radicals, when there are several, which may be identical or different from each other; ). a is a number equal to 0.1 or 2.

 2 in which X X is a 1,3-butadiene moiety substantially corresponding to the formula  RbSiO4 b (III)  2. - Polyorganosiloxane according to claim 1, characterized in that it optionally further comprises other siloxyl pattern (s) corresponding to the formula  2 in which. R has the same meaning as that given for formula (I). B b is a number equal to 0.1, 2 or 3.   wherein the symbols R and X have the meanings given above with respect to formula (I). r is an integer or fractional number ranging from 0 to 9. s is an integer or fractional number ranging from 1 to 10. t is an integer or fractional number ranging from 0 to 9, the sum r + s + t is between 3 and 10 inclusive.

 * and those of average formula X, R and hydroxyl. m is an integer or fractional number ranging from 0 to 1000 n n is an integer or fractional number ranging from 0 to 100 with the additional condition that if n = 0, at least one of the two radicals Y represents the radical X. p is an integer or fractional number ranging from 0 to 50. the sum m + n + p is at least 1  in which . the symbols R and X have the meanings given above with respect to the formula (I). the symbol Y represents a monovalent radical chosen from among the radicals

 random polydiorganosiloxane copolymers, block or block copolymers, of average formula  3. - Polyorganosiloxane according to claim 1, characterized in that it is chosen from  4. - Polyorganosiloxane according to any one of claims 1 to 3, characterized in that the symbol R is chosen from: alkyl radicals, linear or branched, having 1 to 12 carbon atoms, these radicals may be substituted by a or more than one chlorine, bromine or fluorine atom or a -CN group; a phenyl radical, optionally substituted with one or more lower alkyl and / or lower alkoxy radicals or with one or more chlorine atoms.

 - R3 represents a hydrogen atom or a radical selected from among the radicals: methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, n-hexyl; methoxy, ethoxy, propoxy, isopropoxy, butoxy; vinyl, propen-1-yl, allyl, isopropenyl, 1-methyl-2-propenyl, 1-buten-1-yl, 2-butenyl, 3-butenyl, 3-pentenyl, 4-methylpenten-3-yl; 1,4-dimethylpenten-3-yl; phenyl, tolyl; benzyl furyl-2, furyl-3; and the radical of formula  R2 represents a hydrogen atom or a radical chosen from among the radicals: methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, n-hexyl; methoxy, ethoxy, propoxy, isopropoxy, butoxy  R1 represents a hydrogen atom or a radical chosen from among the radicals: methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, n-hexyl; methoxy, ethoxy, propoxy, isopropoxy, butoxy; vinyl, propen-1-yl, allyl, isopropenyl, 1-methyl-2-propenyl, 1-buten-1-yl, 2-butenyl, 3-butenyl, 3-pentenyl, 4-methylpenten-3-yl; 1,4-dimethylpenten-3-yl; phenyl, tolyl; benzyl furyl-2, furyl-3  5. - Polyorganosiloxane according to any one of claims 1 to 4, characterized in that, in the remainder X of formula (II), the various radicals R1, R2 and R3 have the following meanings

 - or R3 forms with R1 and the carbon atoms to which they are attached the following divalent radicals: trimethylene, tetramethylene, methyl-2 propylene or the radicals of formulas

 or R3 forms, with R2 and with the carbon atom to which they are bonded, the tetramethylene, pentamethylene or hexamethylene radicals.  HRaSiO3 a (I ')  6. A process for the preparation of a polyorganosiloxane as defined in any one of claims 1 to 5, characterized in that an at least partial hydrosilylation reaction is carried out in the presence of a catalytically effective amount of a platinum catalyst of a polyorganosiloxane having, per molecule, at least three siloxyl units, at least one siloxyl unit of which corresponds to the formula:  2 in which the symbols R and a have the general or preferential meanings given above for formula (I), on a conjugated ene-yne type compound chosi of those of formula

 wherein R 1, R 2 and R 3 have the general or preferred meanings given above for the formula (II).  the sum r + u is between 3 and 10 inclusive.  . u is an integer or fractional number equal to s + t  the symbols R and r have the general or preferential meanings given above for the formula (V)  in which

 . the symbol Z represents R, a hydroxyl or a hydrogen atom * and of formula  . the sum m + q is at least equal to 1  . q is an integer or fractional number equal to n + p;  the symbols R and m have the general or preferential meanings given above for the formula (IV)  in which

 7. - Process according to claim 6, characterized in that the starting polyorganosiloxane is chosen from those of the formula  RdCleSi (VII I) with d = 0.1, 2 or 3; e = 0.1, 2, 3 or 4 and d + e = 4.  . the symbol W represents a lower alkoxy group, preferably methoxy or ethoxy, or a halogen atom, preferably a chlorine atom, operating in the presence optionally of a halosiloxane, preferably a chlorosilane of formula  . c is 1 or 2  the symbols R and X have the general or preferential meanings given above for formula (I)  or a mixture of hydrolysable silanes comprising at least one silane of formula (VI), in which formula

 8. - Process for the preparation of a polyorganosiloxane as defined in any one of claims 1 to 5, characterized in that one carries out the hydrolysis and the polycondensation of a hydrolysable silane of formula  9. - Process according to claim 8, characterized in that, in the case of obtaining a polymer of formula (IV), an equilibration reaction is carried out between a polydiorganopolysiloxane corresponding to formula (IV) where X is R and Y is OH with a silane of formula (VI). R2 = H with R3 + R1 = - CH2 - CH2 - CH2 c is 1 or 2 the symbol W represents a lower alkoxy group or a halogen atom.  the symbol R has the general or preferential meanings given for formula (I). the symbol X has the general or preferred meanings given for formula (II), excluding the cases where R1 = R2 = R3 = H and  in which:

 10. - A means of means for carrying out the process according to claim 8, a new hydrolysable silane of formula R R has the preferred definition (d1) given above in claim 4 the remainder X has the preferred definition (d3) given above in claim 5; and the polymers PC1, that is to say those of formula (V) in which r r is an integer or fractional number ranging from 0 to 3. s is a whole or fractional number ranging from 3 to 6. t is an integer or fractional number ranging from 0 to 3. the sum r + s + t is between 3 and 6. R has the preferred definition (d1) given above in claim 4; formula (I). the remainder X has the preferred definition (d3) given above in claim 5. Y represent the remainder X or if n = 2, at least one of the two radicals Y represents the remainder X p is an integer or fractional number ranging from 0 to 10  (1) - 100 parts of at least one polydiorganosiloxane chosen from - the polymers PL1, that is to say those of formula (IV) in which. m is an integer or fractional number ranging from 2 to 800. n is an integer or fractional number ranging from 1 to 60 with the additional condition that if n = 1, then both radicals  11. - Polyorganosiloxane composition stable in storage in the absence of gaseous oxygen and crosslinkable to an elastomer, in particular by exposure to ambient temperature with oxygen in the air, characterized in that it comprises  (2) - a catalytically effective amount of a metal curing catalyst.  (3) - 0 to 250 parts of at least one mineral filler.  12. - Composition according to claim 11, characterized in that the curing catalyst is based on cobalt, iron or manganese.  13. - Composition according to claim 11 or 12, characterized in that it further comprises, for 100 parts of polymer (1) - from 1 to 30 parts of oil (4) of the non-reactive polydiorganosiloxane oil type, - and or from 0.2 to 10 parts of an adhesion agent (5).