AU4349796A - New silicon compounds with sterically hindered cyclic amine functions useful for the light and heat stabilization of polymers - Google Patents

Description

WO 96/18667 1 PCT/FR95/01637 NEW SILICONE COMPOUNDS CONTAINING STERICALLY HINDERED CYCLIC AMINE FUNCTIONAL GROUPS WHICH ARE USEFUL FOR THE LIGHT AND THERMAL STABILIZATION OF POLYMERS 5 The present invention relates, in its first subject, to new silicone compounds comprising, per molecule, at least one sterically hindered amine functional group bonded to the silicon atom via an Si-A-C bond where A is an organosilicon residue of low 10 carbon condensation; it also relates, in its first subject, to silicone compounds comprising, per molecule, at least one sterically hindered cyclic amine functional group bonded to the silicon atom via an Si-A-C bond where A is an organosilicon residue of low 15 carbon condensation and at least one other compatibilizing functional group bonded to the silicon via an Si-C bond. It also relates, in a second subject, to a process for the preparation of the said silicone compounds. It further relates, in a third subject, to 20 the use of the same compounds in polymers for improving their resistance to degradation under the effect of ultraviolet (UV) radiation, of atmospheric oxygen and of heat. Indeed, organic polymers, and more 25 particularly polyolefins and polyalkadienes, degrade when they are subjected to external agents and in particular to the combined effect of air and of solar 2 ultraviolet radiation. This degradation is generally limited by the introduction into the polymer of small amounts of stabilizing agents. 5 Among these anti-UV stabilizers, sterically hindered cyclic amines, in particular 2,2,6,6 tetramethylpiperidines, are currently among the most effective. However, in practice, one of the major 10 problems relating to the use of these anti-UV stabilizers is to obtain a good compromise between their effectiveness, which involves their mobility within the polymer, and the permanence of their effect, which involves the use of molecules with a high 15 molecular mass having excellent compatibility with the polymers to be stabilized. It has been proposed in the prior state of the art to resort advantageously to polyorganosiloxanes carrying sterically hindered piperidyl functional 20 groups. Mention may be made, as documents illustrating this prior art, of, for example, the documents Patents JP-A-01/096259, EP-A-0,338,393, EP-A-0,343,717, EP-A-0,358,190, EP-A-0,388,321 and EP-A-0,491,659. However, to the knowledge of the Applicant 25 Company, no document of the prior art describes polyorganosiloxanes which, on the one hand, have a structure in which each sterically hindered cyclic amine functional group is bonded to the silicon atom 3 via an Si-A-C bond where A is an organosilicon residue of low carbon condensation and, on the other hand, are endowed with properties which are useful for improving the resistance of the polymers to degradation under the 5 effect of UV radiation, of atmospheric oxygen and of heat. More precisely, the present invention relates, in its first subject, to a polyorganosiloxane comprising, per molecule, at least 3 siloxy units, 10 including at least one siloxy functional unit of formula: 11)a XSi(O) () 2 in which: e the symbols R' are identical or different and represent a monovalent hydrocarbon radical chosen 15 from the linear or branched alkyl radicals having from 1 to 4 carbon atoms and the phenyl radical; e the symbol X represents a monovalent group of formula: -C~R-CHi-(CH -SiL[{-Z] z in which: 20 e the symbols R, which are identical or different, are chosen from the linear or branched alkyl radicals having from 1 to 4 4 carbon atoms, the phenyl radical or the phenylalkyl radicals where the linear or branched alkyl part has 1 to 3 carbon atoms; e U represents -0- or -NR'-, R' being a radical 5 chosen from a hydrogen atom or a linear or branched alkyl radical having from 1 to 6 carbon atoms; e the symbol Z represents a monovalent group, the free valency of which is carried by a 10 carbon atom, containing a secondary or tertiary amine functional group in a cyclic hydrocarbon chain containing from 8 to 30 carbon atoms, in which the two cyclic carbon atoms situated in the a and a' 15 positions with respect to the cyclic nitrogen atom do not contain a hydrogen atom; e x is a number chosen from 0 and 1; e y is a number chosen from 0, 1 and 2; * z is a number chosen from 1, 2 and 3; 20 e the sum y + z is always equal to 3; e a is a number chosen from 0, 1 and 2. The polyorganosiloxane can additionally have at least one other functional unit of formula: in which: 5 e the symbols R' have the same meanings as those given above with respect to the formula (I); e the symbol W represents a monovalent group containing a compatibilizing functional group 5 chosen from: a linear or branched alkyl radical having more than 4 carbon atoms; a radical of formula -R 2

-COO-R

3 in which R 2 represents a linear or branched alkylene radical having from 5 to 20 carbon atoms and R 3 represents a linear or branched 10 alkyl radical having from 1 to 12 carbon atoms; a radical of formula -R 4 -O- (Rs-O).-R' in which R' represents a linear or branched alkylene radical having from 3 to 15 carbon atoms, Rs represents a linear or branched alkylene radical having from 1 15 to 3 carbon atoms, c is a number from 0 to 10 and R' represents a hydrogen atom, a linear or branched alkyl radical having from 1 to 12 carbon atoms or an acyl radical -CO-R 7 where R 7 represents a linear or branched alkyl radical having from 1 to 11 20 carbon atoms; e b is a number chosen from 0, 1 and 2. The other possible siloxy unit(s) of the polyorganosiloxane correspond(s) to the formula: ( (H) Si(O)4(d +e) 2 in which: 6 * the symbols R' have the. same meanings as those given above with respect to the formula (I); e d is a number chosen from 0, 1, 2 and 3; * e is a number chosen from 0 and 1; 5 e the sum d + e is not greater than 3. The siloxy units of formula (I), when there are more than two of them, can be identical to or different from one another; the same comment also applies to the siloxy units of formulae (III) and (IV). 10 In the present statement, the following definitions will be understood to apply: - "cyclic amine functional groups":- monovalent Z groups which do not have the divalent [when, in the formula (II), z = 1], trivalent (when z = 2) 15 or tetravalent (when z = 3) organosilicon linking unit via which they are bonded to the silicon atoms; - "compatibilizing functional groups": optional monovalent W groups which are directly bonded to 20 the silicon atoms (in this case, Si-C bonds are then formed); - "mixed organopolysiloxanes (or polymers)": polymers which have both amine functional group(s) and compatibilizing functional group(s). 25 Taking into account the values which the symbols a, b, d and e can take, it should further be understood that the polyorganosiloxanes according to the invention can thus have a linear, cyclic or 7 branched (resin) structure or a mixture of these structures. When it concerns linear polymers, the latter can optionally have up to 50 mol % of branching [units of 'T" (BSiO 3 2 ) and/or "Q" (SiO 4 2 ) types, B being 5 a monovalent organic residue]. When it concerns polyorganosiloxane resins, the latter are composed of at least two types of different siloxy units, namely "n" (B 3 SiO, 1 2 ) and/or "T" units and optionally "DN (B 2 SiO 2 2 )] units; the number of 10 "M" units/number of "Q" and/or "TN units ratio is generally between 4/1 and 0.5/1 and the number of "D" units/number of "Q" and/or "T" units ratio is generally between 0 to 100/1. The numbers of the units of formulae (I), and 15 optionally (III) and (IV), are advantageously such that the polyorganosiloxanes according to the invention contain: - at least 0.5 mol %, preferably from 8 to 90 mol %, of amine functional groups, and optionally 20 - at least 0.5 mol %, preferably from 8 to 90 mol %, of compatibilizing functional groups. The mol % values indicated express the number of moles of functional groups per 100 silicon atoms. The preferred R' radicals are: methyl, ethyl, 25 n-propyl, isopropyl or n-butyl; more preferentially, at least 80 mol % of the R1 radicals are methyls. The groups X containing cyclic amine functional group(s) which are preferred are chosen from 8 the groups X of formula (II) defined above in which the symbols R, U, x, y and z have the meanings given above and the symbol Z is a group of formula:

R

8 N-IP (V) (CH2 where: 5 e the R' radicals, which are identical to or different from one another, are chosen from the linear or branched alkyl radicals having from 1 to 3 carbon atoms, the phenyl radical and the benzyl radical; 10 e R 9 is chosen from a hydrogen atom, the linear or branched alkyl radicals having from 1 to 12 carbon atoms, the alkylcarbonyl radicals or the alkyl residue is a linear or branched residue having from 1 to 8 carbon atoms, the phenyl and benzyl 15 radicals and an 0- radical; and e f is a number chosen from 0 and 1. More preferentially, the groups X containing cyclic amine functional group(s) are chosen from the groups X of formula (II) defined above in which: 20 e the R radicals are methyl and/or phenyls; e U represents -0- or -NR'-, R' being a hydrogen atom or a methyl radical; e Z is a cyclic amine functional group of formula 9 (V) where the R" radicals are methyls, the R' radical represents a hydrogen atom or a methyl radical and e f is a number equal to 1; 5 e x is equal to zero, whereas y and z have the meanings given above with respect to the formula (II). The preferred optional compatibilizing functional groups W are chosen: from a linear or 10 branched alkyl radical having from 5 to 18 carbon atoms; a radical of formula -R 2

-COO-R

3 in which R 2 represents a linear or branched alkylene radical having from 8 to 12 carbon atoms and R' represents a linear or branched alkyl radical having from 1 to 6 carbon atoms; 15 or a radical of formula -R'-0- (R-O).-R 6 in which R 4 represents a linear or branched alkylene radical having from 3 to 6 carbon atoms, R 5 represents a linear or branched alkylene radical having from 2 to 3 carbon atoms, c is a number from 0 to 6 and R 6 represents a 20 hydrogen atom, a linear or branched alkyl radical having from 1 to 6 carbon atoms or an acyl radical

-CO-R

7 where R 7 represents a linear or branched alkyl radical having from 1 to 5 carbon atoms. The compatibilizing functional groups W are 25 more preferentially chosen from the n-octyl, n-undecyl, n-dodecyl, n-tridecyl or methyl or ethyl decamethylenecarboxylate radicals. The present invention, taken in its first 10 subject, is more precisely still targeted at: - statistical, sequenced or block, linear, optionally mixed polydiorganosiloxane copolymers of average formula: R .

R1R I I I Il Y-si-o-j- Si-- - so s-o ---- v n P R 5 in which: e the symbols R', X and W have the general meanings given above with respect to the formulae (I) and (III); e the symbols Y represents a monovalent radical 10 chosen from R1, X, W and a hydrogen atom; e m is a whole or fractional number ranging from 0 to 180; e n is a whole or fractional number ranging from 0 to 180; 15 e p is a whole or fractional number ranging from 0 to 30; e q is a whole or fractional number ranging from 0 to 100; e with the conditions according to which: 20 - if m is other than 0 and optionally if n is other than 0: the sum m + n + p + q lies in the range from 5 to 200; the ratio 100m / m + n + p + q + 2 0.5; and the ratio 100n / m + n + p + q + 2 a 0.5, this ratio being identical to or 11 different from the preceding ratio; - if m = 0 and optionally if n is other than 0: at least one of the Y substituents represents the X radical; the sum n + p + q lies in the range from 5 5 to 100; and the ratio 100n / n + p + q + 2 z 0.5; - if m is other than 0 and n = 0: the sum m + p + q lies in the range from 5 to 100; the ratio 100m / m + p + q + 2 a 0.5; and optionally at 10 least one of the Y substituents represents the W radical; - if m = 0 and n = 0: the sum p + q lies in the range from 5 to 100; one of the Y substituents being the X radical; and optionally the other Y 15 substituent being the W radical; and those of average formula: II I I SSi-O i-C SSi-O (VII) XW H R1k in which: - the symbols R', X and W have the general meanings given above with respect to the formulae (I) and 20 (III); - r is a whole or fractional number ranging from 1 to 9; 12 - s is a whole or fractional number ranging from 0 to 9; - t is a whole or fractional number ranging from 0 to 1.5; 5 u is a whole or fractional number ranging from 0 to 5; - the sum r + s + t + u lies in the range from 3 to 10. The polymers of formula (VI) which are 10 preferred (so-called LP1 polymers) or highly preferred (so-called LP2 polymers) are those in which: - the symbols Y represent R'; - m is a whole or fractional number ranging from 1 to 90; 15 n is a whole or fractional number ranging from 0 to 90; - p is a whole or fractional number ranging from 0 to 15; - q is a whole or fractional number ranging from 0 20 to 50; - the sum m + n + p + q is a whole or fractional number ranging from 10 to 100; the ratio 100m / m + n + p + q + 2 lies in the range from 8 to 90; 25 with the condition according to which if n is other than 0, the ratio 100n / m + n + p + q + 2 lies in the range from 8 to 90, it being possible for this ratio to be identical to or different 13 from the preceding ratio; the R', X and W radicals simultaneously have the preferential definitions (in the case of LP1 polymers) or more preferential definitions (in the 5 case of LP2 polymers) given above with respect to each of them. The polymers of formula (VII) which are preferred (so-called CPl polymers) or highly preferred (so-called CP2 polymers) are those in which: 10 r is a whole or fractional number ranging from 1 to 4.5; - s is a whole or fractional number ranging from 0 to 4.5; - t is a whole or fractional number ranging from 0 15 to 0.75; - u is a whole or fractional number ranging from 0 to 2.5; - the sum r + s + t + u is a whole or fractional number ranging from 3 to 5; 20 the R 1 , X and W radicals simultaneously have the preferential definitions (in the case of the CP1 polymers) or more preferential definitions (in the case of the CP2 polymers) given above with respect to each of them. 25 The polymers of formula (VI), which are especially well suited (so-called ELP1 polymers) or very especially well suited (so-called ELP2 polymers) are the LP1 or LP2 polymers defined above in which the 14 symbol n is a number ranging from 1 to 90. The polymers of formula (VII), which are especially well suited (so-called ECP1 polymers) or very especially well suited (so-called ECP2 polymers) 5 are the CP1 or CP2 polymers defined above in which the symbol s is a number ranging from 1 to 4.5. The optionally mixed organopolysiloxanes of the invention can advantageously be obtained from, and this constitutes the second subject of the invention: 10 corresponding organohydropolysiloxanes (H), which are free of group(s) X containing amine functional group(s) Z and of compatibilizing functional group(s) W, - the organic compound(s) which is (are) 15 ethylenically unsaturated at the chain end (k), from which the group(s) X containing amine functional group(s) Z derive(s), - and optionally the compound(s) which is (are) ethylenically unsaturated at the chain end (2), 20 from which the W functional group(s) derive(s). Thus, the optionally mixed polyorganosiloxanes of the invention can be obtained by carrying out: - in the case of polymers containing solely amine 25 functional group(s): an addition (hydrosilylation) reaction, or - in the case of mixed polymers containing amine functional group(s) and containing compatibilizing 15 functional group(s): two simultaneous or successive addition (hydrosilylation) reactions, starting with: corresponding organohydropolysiloxanes (H) free of group(s) X containing amine functional 5 group(s) Z and of W functional group(s), the organic compound(s) which is(are) ethylenically unsaturated at the chain end (*), from which the group(s) X containing amine functional group(s) Z derive(s), and optionally the compound(s) which is(are) ethylenically unsaturated 10 at the chain end (S), from which the W functional group (s) derive (s). These hydrosilylation reactions can be carried out at a temperature of the order of 20 to 200 0 C, preferably of the order of 60 to 120"C, in the 15 presence of a catalyst based on a metal of the platinum group; mention may in particular be made of the platinum derivatives and complex described in US-A 3,715,334, US-A-3,814,730, US-A-3,159,601 or US-A 3,159,662. 20 The amounts of catalysts used are of the order of 1 to 300 parts per million, expressed as metal with respect to the reaction mixture. In the definition of the "mol of (M)", the olefinic unsaturation capable of reacting with (H) by 25 hydrosilylation will be regarded as the unit entity. Likewise, in the definition of the "mol of (M)", the olefinic unsaturation capable of reacting with (H) by hydrosilylation will be regarded as the unit entity.

16 The amounts of reactants which can be used generally correspond to a [(*) + optionally (W)]/SiH [of (H)] molar ratio which is of the order of 1 to 5 and preferably of the order of 1 to 2. 5 The hydrosilylation reactions can take place in bulk or, preferably, in a volatile organic solvent such as toluene, xylene, methylcyclohexane, tetrahydrofuran, heptane, octane or isopropanol; the reaction mixture can additionally contain a buffer 10 agent consisting in particular of an alkali metal salt of a monocarboxylic acid, such as, for example, sodium acetate. At the end of the reactions, the crude optionally mixed polyorganosiloxanes which are obtained 15 can be purified, in particular by passing through a column filled with an ion exchange resin and/or by simple evaporation of the reactants introduced in excess and optionally of the solvent used by heating between 100 and 180*C under reduced pressure. 20 The organohydropolysiloxanes (H) which are used, for example, for the preparation of the linear mixed polydiorganosiloxanes of formula (VI) are those of formula: R I IR Y' i O - -i- - i-O---- -Y' (VIII) R1 -- H -v R q H in which: 17 - the symbols R' and q have the general or preferential meanings given above with respect to the formula (VI); - the symbols Y' represent R' or a hydrogen atom; 5 v is a whole or fractional number equal to m + n + P; - with the condition according to which, if v = 0, q is a number lying in the range from 5 to 100 and then at least one of the Y' radicals represents a 10 hydrogen atom. The organohydropolysiloxanes (H) which are used, for example, for the preparation of the cyclic mixed polydiorganosiloxanes of formula (VII) are those of formula: R1(H 15 in which: - the symbols R 1 and u have the general or preferential meanings given above with respect to the formula (VII); - w is a whole or fractional number equal to r + s + 20 t; - the sum u + w lies in the range from 3 to 10. Such organohydropolysiloxanes (H) of formulae (VIII) and (IX) are known in the literature and some 18 are commercially available. The unsaturated organic compounds (T), from which the groups X containing cyclic amine functional group(s) derive, are preferably those of formula: R8 _S 7Y 9 CH,=CH-4CH,)-Si- U N-R S- x (Hy 7 L 8 X

R

8 5 in which the symbols R, U, R*, R 9 , f, -x, y and z have the general or preferential meanings given above with respect to the formulae (II) and (V). As compounds (M), mention may be made, as specific examples, of the compounds of formulae: 19 CHg-;Si-CH3 CH-Si--O

N-R

9 N N R9R 0 00 N N R9 R9 N in which R' is a hydrogen atom or a methyl radical. The unsaturated organic compounds (M) containing cyclic amine functional group(s) of formula (X) are compounds which, to the knowledge of 5 the Applicant company, are novel products. The same compounds can easily be synthesized by reacting: e an alcohol or an amino derivative of formula: RS 8 H-U

N-R

9 (XI) f#R8 in which U, R*, R* and f have the general or preferential meanings given above with respect to 20 the formulae (II) and (V) (in the case where U = -0-, the starting material is an alcohol; in the case where U = -NR'-, the starting material is an amino derivative of the cyclic amine); 5 with a chlorosilane of formula:

CH

2 =CH-(CHp)Si-(C)z (XMI) in which x, y and z have the meanings given above with respect to the formula (II). Mention may be made, as specific examples of reactants of formula (XI), of: 4-hydroxy-2,2,6,6 10 tetramethylpiperidine and 4-hydroxy-1,2,2, 6,6 pentamethylpiperidine. Mention may be made, as specific examples of reactants of formula (XII), of:

CH

2 =CH-Si (CH) 2 C1, CH 2 =CH-Si (CH) 2 (Cl) 2 and CH 2 =CH-Si- (Cl) . 15 The reaction between an alcohol or an amino derivative of formula (XI) and a chlorosilane of formula (XII) is generally carried out in the presence of a base of tertiary aliphatic amine type, such as triethylamine for example, the reaction being carried 20 out in an inert polar solvent, such as tetrahydrofuran for example, and at a temperature ranging from room temperature (23*C) to the reflux temperature of the reaction mixture. The amount of aSi-Cl functional groups to be used is generally equivalent to that of 25 the alcohol or HNR' functional groups. It is preferable 21 to use an excess of tertiary amino base with respect to the theoretical amount of HCl which can be released. At the end of the reaction, the compounds (*) obtained are purified according to the conventional techniques such 5 as, for example, distillation under reduced pressure and/or recrystallization from an appropriate solvent. The unsaturated compounds (S), from which the W functional groups derive, are compounds having an ethylenic unsaturation, situated at the chain end, 10 capable of reacting in a hydrosilylation reaction in the presence of a catalyst based on a metal from the platinum group. As compounds (9), mention may be made, as examples, of 1-octene, 1-undecene, 1-dodecene, 1 15 tridecene, or methyl or ethyl undecenoate. The optionally mixed polyorganosiloxanes according to the invention can be used as stabilizers in combating light, oxidative and thermal degradation of organic polymers, and this constitutes the third 20 subject of the invention. Mention may be made, as examples of such organic polymers, of polyolefins, polyurethanes, polyamides, polyester, polycarbonates, polysulphones, polyethersulphones, polyetherketones, acrylic polymers, 25 their copolymers and their mixtures. Among these polymers, the compounds of the invention have a more particularly effective action with polyolefins and polyalkadienes, such as 22 polypropylene, high density polyethylene, linear low density polyethylene, low density polyethylene, polybutadiene, their copolymers and their mixtures. Taking into account the wide possibilities of 5 variations in the relative numbers of the various siloxy units present in the siloxane chain of the mixed compounds of the invention, these said compounds can be easily adaptable to the various problems to be solved. Yet another subject of the present invention 10 therefore consists in the compositions containing organic polymer stabilized against the harmful effects of heat and of UV by an effective amount of at least one optionally mixed polyorganosiloxane compound. These compositions generally contain from 15 0.04 to 20 milliequivalents of sterically hindered amine functional group(s) per 100 g of polymer to be stabilized. The polymeric compositions stabilized according to the invention preferably contain from 0.20 20 to 4 milliequivalents of sterically hindered amine functional group(s) per 100 g of polymer. By way of indication, the stabilized polymeric compositions generally contain from 0.01 % to 5 % by weight of optionally mixed polyorganosiloxane 25 compound with respect to the polymer. The addition of the optionally mixed polyorganosiloxane compounds can be carried out during or after the preparation of the polymers.

23 These compositions can additionally contain all the additives and stabilizers generally used with the polymers which they contain. Thus, it is possible to use the following stabilizers and additives: 5 antioxidants, such as alkylated monophenols, alkylated hydroquinones, hydroxylated diphenyl sulphides, alkylidenebisphenols, benzyl compounds, acylaminophenols, enters or amides of 3-(3,5-di-tert butyl-4-hydroxylphenyl)propionic acid or esters of 3 10 (3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid; light stabilizers, such as optionally substituted benzoic acid esters, acrylic enters, nickel compounds or oxalamides; phosphites and phosphonites; metal deactivators; compounds which destroy peroxides; 15 polyamide stabilizers; nucleation agents; fillers and reinforcing agents; or other additives, such as, for example, plasticizers, pigments, optical brighteners or flame retardants. The polymer compositions thus stabilized can 20 be applied in the most varied forms, for example in the form of moulded items, sheets, fibres, cellular materials (foam), sections or coating products, or as film-forming agents (binders) for paints, varnishes, adhesives or cements. 25 The following examples illustrate the present invention. In these examples, theoretical concentration of amine functional groups Z, expressed in 24 milliequivalents (meq) per 100 g of silicone oil, is understood to mean the concentration which the silicone oil would have if all the amine functional groups involved were grafted. 5 Example 1 Example of the preparation of a mixed polyorganosiloxane containing silicon-containing linking units. A - Preparation of dimethylvinyl(2,2,6,6-tetramethyl 10 4-piperidyloxv)silane: 31.45 g (0.2 mol) of 4-hydroxy-2,2,6,6 tetramethylpiperidine, 81 g (0.8 mol) of anhydrous triethylamine (dried over potassium- hydroxide) and 70 g of anhydrous tetrahydrofuran are introduced into a 15 250 cm 3 reactor equipped with a central stirrer system and maintained internally under a dry nitrogen atmosphere. The mixture is stirred and brought to a temperature of 65*C. 24.13 g (0.2 mol) of dimethylvinylchlorosilane are then run in over a period 20 of 50 minutes and the mixture is left stirring for a further 3 hours at the same temperature. The triethylamine hydrochloride formed is filtered off on a cellulose filter and rinsed with 35 g of tetrahydrofuran. The excess triethylamine and the 25 tetrahydrofuran are first distilled off from the filtrate at atmospheric pressure and then a distillation is carried out under reduced pressure 25 (4.66 x 102 Pa) at 90 0 C in order to isolate 28 g (0.116 mol) of 99 % pure by weight dimethylvinyl (2,2,6, 6-tetramethyl-4-piperidyloxy) silane (purity determined by gas phase chromatography). 5 B - Preparation of the mixed polyorganosiloxane: 26 g of toluene are introduced into a 100 cm 3 reactor equipped with a central stirrer system and maintained internally under a dry nitrogen atmosphere. The mixture is stirred and brought to a temperature of 10 100*C and then 4.2 nm 2 (4.2 pl) of a solution in divinyltetramethyldisiloxane of a platinum complex containing 11.9 % by weight of platinum attached to divinyltetramethyldisiloxane as ligand (Karstedt catalyst) are introduced. 5 g of a 15 polymethylhydrosiloxane oil (i.e. 0.0792 mol of Si-H functional group), the characteristics of this oil being as follows: e Mn = 3160 g; * 1580 meq H/100 g, 20 e average structure:

(CH

3

)

3 SiO- i-O- -Si(CH 3

)

3 H .. 50 and 11.48 g (0.0475 mol) of 99 % pure by weight dimethylvinyl(2,2,6,6-tetramethyl-4-pyridyloxy)silane are then run in simultaneously over 80 minutes. 2 hours after the beginning of the addition, the degree of 26 conversion of the hydrosilane functional groups is 60 % (in moles). 10.08 g (0.057 mol) of 95 % pure by weight 1-dodecene are then run in over 20 minutes. 4 hours after the beginning of the first addition, the degree 5 of conversion of the hydrosilane functional groups is 68 % in moles; 2.1 nm 3 (2.1 pl) of Karstedt catalyst are then added again. 21 hours after the beginning of the first addition, the degree of conversion of the hydrosilane functional groups is 82.3 %; 4.2 nm 3 10 (4.2 pl) of Karstedt catalyst are added yet again. 24 hours after the beginning of the first addition, the degree of conversion of the hydrosilane functional groups is 85.6 %. 4.04 g (0.023 mol) of 95 % pure by weight 15 1-dodecene are again run into the reaction mixture. 29 hours after the beginning of the first addition, the degree of conversion of the hydrosilane functional groups is 88 %. The product obtained is then evaporated for 2 20 hours at 110*C under a reduced pressure of 1.33 x 102 Pa and 17 g of a clear light-brown oil are recovered, the characteristics of this oil being as follows: * Mn = 12774 g; * 239.3 meq of amine functional groups Z/100 g (this 25 basicity value is measured by titrating the oil obtained using a 0.02N perchloric acid solution); e average structure of the oil: 27 CH CH1 (CH ) Sio- -Si-0- -- S-So--iCi (CH2) 2 . 30 HCH 4 .

6 Si(CH 1 a 2 CH, CHI N CHI CHI SH e proportion of Z functional groups: 57.7 % (in moles of functional groups per 160 atoms of silicon); e proportion of W functional group: 26.9 %. 5 Example 2 Example of the preparation of another mixed polyorganosiloxane containing silicon-containing linking units. A - Preparation of methylvinylbis(2,2,6,6-tetramethyl 10 4-piperidyloxy) silane: 87.7 g (0.558 mol) of 4-hydroxy-2,2,6,6 tetramethylpiperidine, 210.7 g (2.086 mol) of anhydrous triethylamine (dried over potassium hydroxide) and 187.15 g of anhydrous tetrahydrofuran are introduced 15 into a 500 cm 3 reactor equipped with a central stirrer system and maintained internally under a dry nitrogen atmosphere. The mixture is stirred and brought to a temperature of 57 0 C. 42.4 g (0.3 mol) of 28 methylvinyldichlorosilane are then run in over a period of 55 minutes. The temperature of the mixture rises to 72*C. After the end of the addition, the reaction mixture is left stirring for a further 8 hours at 60 0 C. 5 The excess triethylamine and tetrahydrofuran are distilled off and then the mixture is filtered on a cellulose filter in order to remove the triethylamine hydrochloride and to obtain 81 g (0.19 mol) of 90 % pure by weight methylvinylbis (2,2,6, 6-tetramethyl-4 10 piperidyloxy)silane (purity determined by gas phase chromatography). Distillation is then continued under reduced pressure (7.98 x 102 Pa) at 157 0 C to obtain 54.3 g (0.135 mol) of the same 95 % pure by weight product. 15 B - Preparation of the mixed polvorganosiloxane: 44.8 g of toluene are introduced into a 100 cm 3 reactor equipped with a central stirrer system and maintained internally under a dry nitrogen atmosphere. The mixture is stirred and brought to a 20 temperature of 100 0 C and then 4.2 nm 2 (4.2 pl) of a solution in divinyltetramethyldisiloxane of a platinum complex containing 11.9 % by weight of platinum attached to divinyltetramethyldisiloxane as ligand (Karstedt catalyst) are introduced. 5.4 g of a 25 polymethylhydrosiloxane oil (i.e. 0.085 mol of Si-H functional group), the characteristics of this oil being as follows: e Mn =3160 g; 29 * 1580 meq H/100 g, e average structure: 'CH ( CH)Sio Si- Si(CH3)3 H 50 and 20.9 g (0.052 mol) of 95 % pure by weight methylvinylbis (2,2,6,6-tetramethyl-4 5 piperidyloxy)silane are then run in simultaneously over 80 minutes. 3.5 hours after the beginning of the addition, the degree of conversion of the hydrosilane functional groups is 51.6 % (in moles)-. 4 hours 10 minutes after the beginning of the addition, 13.9 g 10 (0.078 mol) of 95 % pure by weight 1-dodecene are introduced over 15 minutes. 18 hours after the beginning of the first addition, the degree of conversion of the hydrosilane functional groups is 92 %. 5.7 nm 3 (5.7 pl) of Karstedt catalyst are then 15 added again. 42 hours after the beginning of the first addition, the degree of conversion of the hydrosilane functional groups is 97 %. The product obtained is then evaporated for 2 hours at 180 0 C under a reduced pressure of 7.98 x 102 20 Pa and 25.8 g of a clear light-brown oil are recovered, the characteristics of this oil being as follows: e Mn = 18050 g; e 352.6 meq of amine functional groups Z/100 g (this basicity value is measured by titrating the oil 30 obtained using a 0.02N perchloric acid solution); e average structure of the oil: CH3 CHI CHI I I I(C .) (CH)3Sio Si-O Si-O Si- 0 Si(CH CH CH, '(4 Z ) 2 ±31,5 C 1H 1.5 H-N O-SiCH 3 0 CH3 CH. H CH N CH3 * proportion of Z functional groups: 60.6 % (in moles of functional groups per -100 atoms of 5 silicon); * proportion of W functional group: 32.7 %. Example 3 Photostabilization of polypropylene (PP) Preparation of the compositions: 10 - mixing 100 parts by weight of PP, Eltexe PEV001P (grade 10) + 0.2 part of a commercial antioxidant (cf. definition below) + 0.1 part of calcium stearate + 0.2 part of stabilizer for 3 minutes at 160*C; - compression under a platen press at 190 0 C (brought 15 into contact for 1 minute + maintained at 250 x 105 Pa for 1 minute + cooling at the same pressure for 1 minute). Virtually circular discs with a thickness of 31 200 micrometres are thus obtained, test pieces being cut from these discs. * Control composition a: stabilizer = Chimasorb 944 (cf. formula below) containing 341 meq of 5 piperidyl functional groups per 100 g of stabilizer. * Compositions b and c: stabilizers = silicone oils in Examples 1 (part B) and 2 (part B) respectively. 10 Definition of the commercial antioxidant used: 50/50 mixture by weight of pentaerythrityl tetrakis[3-(4'-hydroxy-3',5'-di(tert butyl)phenyl)propionate] (marketed under the name Irganox* 1010) and of tris[2,4-di(tert-butyl)phenyl] 15 phosphite (marketed under the name Irgafos* 168). Formula of Chimasorb* 944: N N NH N N I I IS I Cs

-

-n>1 The three compositions are tested under UV-A. As degradation under UV-A is much slower than under UV-B, the stabilization test is carried out 20 simply by comparing the times (T) after which failure 32 of the test pieces occurs. Three test pieces are tested for each composition. Time of failure of the test piece. Concentration of T (hour) amine functional T/number of group meq/100 g (Meq/100 g of oil) Coamposition Test Test Test mean piece 1 piece 2 piece 3 a 744 768 798 770 341 2.26 5 b 878 844 1079 97 239.3 3.75 0 1914 1938 1958 1937 342.6 5.65

Claims (18)

1. Polyorganosiloxane, characterized in that it comprises, per molecule, at least 3 siloxy units, including at least one siloxy functional unit of 5 formula: 2 in which: - the symbols R' are identical or different and represent a monovalent hydrocarbon radical chosen from the linear or branched alkyl radicals having 10 from 1 to 4 carbon atoms and the phenyl radical; - the symbol X represents a monovalent group of formula: - C4H- CFH-(CHY 7TSLUZ] Z MU in which: the symbols R, which are identical or 15 different, are chosen from the linear or branched alkyl radicals having from 1 to 4 carbon atoms, the phenyl radical or the phenylalkyl radicals where the linear or branched alkyl part has 1 to 3 carbon atoms; 20 U represents -0- or -NR'-, R' being a radical chosen from a hydrogen atom or a linear or 34 branched alkyl radical having from 1 to 6 carbon atoms; e the symbol Z represents a monovalent group, the free valency of which is carried by a carbon 5 atom, containing a secondary or tertiary amine functional group in a cyclic hydrocarbon chain containing from 8 to 30 carbon atoms, in which the two cyclic carbon atoms situated in the a and a' positions with respect to the cyclic 10 nitrogen atom do not contain a hydrogen atom; e x is a number chosen from 0 and 1; e y is a number chosen from 0, 1 and 2; e z is a number chosen from 1, 2 and 3; e the sum y + z is always equal to 3; 15 e a is a number chosen from 0, 1 and 2.

2. Polyorganosiloxane according to claim 1, characterized in that the R' radicals are: methyl, ethyl, n-propyl, isopropyl or n-butyl.

3. Polyorganosiloxane according to claim 1 20 or 2, characterized in that the groups X containing cyclic amine functional group(s) are chosen from the groups X of formula (II) defined above in which the symbols R, U, x, y and z have the meanings given above and the symbol Z is a group of formula: 35 ~R N-It (V) fCH 2 _* 0I where e the R 8 radicals, which are identical to or different from one another, are chosen from the linear or branched alkyl radicals having from 1 to 5 3 carbon atoms, the phenyl radical and the benzyl radical; e R' is chosen from a hydrogen atom, the linear or branched alkyl radicals having from 1 to 12 carbon atoms, the alkylcarbonyl radicals or the alkyl 10 residue is a linear or branched residue having from 1 to 8 carbon atoms, the phenyl and benzyl radicals and an 0- radical; and e f is a number chosen from 0 and 1.

4. Polyorganosiloxane according to any one 15 of claims 1 to 3, characterized in that it additionally comprises at least one other functional unit of formula: (R)bW i(O)3-b 2 in which: e the symbols R' have the same meanings as those 20 given above with respect to the formula (I); 36 e the symbol W represents a monovalent group containing a compatibilizing functional group chosen from: a linear or branched alkyl radical having more than 4 carbon atoms; a radical of 5 formula -R 2 -COO-R 3 in which R 2 represents a linear or branched alkylene radical having from 5 to 20 carbon atoms and R 3 represents a linear or branched alkyl radical having from 1 to 12 carbon atoms; a radical of formula -R 4 -O- (R-0).-R 6 in which R 4 10 represents a linear or branched alkylene radical having from 3 to 15 carbon atoms, R 5 represents a linear or branched alkylene radical having from 1 to 3 carbon atoms, c is a number from 0 to 10 and R' represents a hydrogen atom, -a linear or branched 15 alkyl radical having from 1 to 12 carbon atoms or an acyl radical -CO-R 7 where R 7 represents a linear or branched alkyl radical having from 1 to 11 carbon atoms; e b is a number chosen from 0, 1 and 2. 20

5. Polyorganosiloxanes according to claim 4, characterized in that the compatibilizing functional groups W are chosen: from a linear or branched alkyl radical having from 5 to 18 carbon atoms; a radical of formula -R 2 -COO-R 3 in which R 2 25 represents a linear or branched alkylene radical having from 8 to 12 carbon atoms and R' represents a linear or branched alkyl radical having from 1 to 6 carbon atoms; or a radical of formula -R'-O- (R 5 -0) 0 -R 6 in which R 4 37 represents a linear or branched alkylene radical having from 3 to 6 carbon atoms, R' represents a linear or branched alkylene radical having from 2 to 3 carbon atoms, c is a number from 0 to 6 and R' represents a 5 hydrogen atom, a linear or branched alkyl radical having from 1 to 6 carbon atoms or an acyl radical -CO-R 7 where R 7 represents a linear or branched alkyl radical having from 1 to 5 carbon atoms.

6. Polyorganosiloxane according to any one 10 of claims 1 to 5, characterized in that it additionally comprises other siloxy unit(s) of formula: d e i(O4-(d +-91) 2 in which: e the symbols R2 have the same meanings as those given above with respect to the formula (I); 15 e d is a number chosen from 0, 1, 2 and 3; e e is a number chosen from 0 and 1; e the sum d + e is not greater than 3.

7. Polyorganosiloxane according to any one of claims 1 to 6, characterized in that it is chosen 20 from: - statistical, sequenced or block, linear, optionally mixed polydiorganosiloxane copolymers of average formula: 38 0 -- _SIr I ( Y-i-o -- o -o --o-SI y1 v in which: * the symbols R', X and W have the general meanings given above with respect to the formulae (I) and (III) ; 5 e the symbols Y represents a monovalent radical chosen from R1, X, W and a hydrogen atom; e m is a whole or fractional number ranging from 0 to 180; e n is a whole or fractional number ranging from 0 10 to 180; e p is a whole or fractional number ranging from 0 to 30; e q is a whole or fractional number ranging from 0 to 100; 15 e with the conditions according to which: - if m is other than 0 and optionally if n is other than 0: the sum m + n + p + q lies in the range from 5 to 200; the ratio 100m / m + n + p + q + 2 a 0.5; and the ratio 100n / m + n + p + q + 20 2 a 0.5, this ratio being identical to or different from the preceding ratio; - if m = 0 and optionally if n is other than 0: at least one of the Y substituents represents the X 39 radical; the sum n + p + q lies in the range from 5 to 100; and the ratio 100n /n + p + q + 2 a 0.5; - if m is other than 0 and n = 0: the sum m + p + 5 q lies in the range from 5 to 100; the ratio 100m / m + p + q + 2 a 0.5; and optionally at least one of the Y substituents represents the W radical; - if m = 0 and n = 0: the sum p + q lies in the 10 range from 5 to 100; one of the Y substituents being the X radical; and optionally the other Y substituent being the W radical; and those of average formula: SSi- -Si- -Si-O. (VII) WR1 r - -J SL -it -- U in which: 15 the symbols R', X and W have the general meanings given above with respect to the formulae (I) and (III); - r is a whole or fractional number ranging from 1 to 9; 20 s is a whole or fractional number ranging from 0 to 9; - t is a whole or fractional number ranging from 0 40 to 1.5; - u is a whole or fractional number ranging from 0 to 5; - the sum r + s + t + u lies in the range from 3 to 5 10.

8. Mixed linear ELP1 polyorganosiloxane according to claim 7, characterized in that: - the symbols Y represent R'; - m is a whole or fractional number ranging from 1 10 to 90; - n is a whole or fractional number ranging from 1 to 90; - p is a whole or fractional number ranging from 0 to 15; 15 q is a whole or fractional number ranging from 0 to 50; - the sum m + n + p + q is a whole or fractional number ranging from 10 to 100; - the ratio 100m m + n + p + q + 2 lies in the 20 range from 8 to 90; - the ratio 100n /m + n + p + q + 2 lies in the range from 8 to 90, it being possible for this ratio to be identical to or different from the preceding ratio; 25 - the radicals R', X and W simultaneously have the definitions given above with respect to each of them in the abovementioned claims 2, 3 and 5.

9. Mixed cyclic ECP1 polyorganosiloxane 41 according to claim 7, characterized in that: - r is a whole or fractional number ranging from 1 to 4.5; - s is a whole or fractional number ranging from 1 5 to 4.5; - t is a whole or fractional number ranging from 0 to 0.75; - u is a whole or fractional number ranging from 0 to 2.5; 10 the sum r + s + t + u is a whole or fractional number ranging from 3 to 5; - the radicals R', X and W simultaneously have the definitions given above with respect to each of them in the abovementioned claims 2, 3 and 5. 15 10. Process for the preparation of an optionally mixed polyorganosiloxane according to any one of claims 1 to 9, characterized in that it consists in carrying out: - in the case of polymers containing solely amine 20 functional group(s): an addition (hydrosilylation) reaction, or - in the case of mixed polymers containing amine functional group(s) and containing compatibilizing functional group(s): two simultaneous or 25 successive addition (hydrosilylation) reactions, starting with: corresponding organohydropolysiloxanes (H) free of group(s) X containing amine functional group(s) Z and of W functional group(s), the organic 42 compound(s) which is(are) ethylenically unsaturated at the chain end (M), from which the group(s) X containing amine functional group(s) Z derive(s), and optionally the compound(s) which is(are) ethylenically unsaturated 5 at the chain end (2), from which the W functional group(s) derive(s), and in that the amount of the reactants involved correspond to a [( + optionally (Z)]/SiH [of (H)] molar ratio which is of the order of 1 to 5.

10

11. Process according to claim 10, characterized in that the unsaturated organic compounds (M), from which the groups X containing cyclic amine functional group(s) derive, are those of formula: - R 8 CH)x-U )(X) M=H4C2--U N- z in which the symbols R, U, R 8 , R 9 , f, x, y and z have 15 the meanings given above with respect to the formulae (II) and (V).

12. Process according to claim 11, characterized in that the unsaturated organic compounds (4) of formula (X) are prepared by reacting: 20 an alcohol or an amino derivative of formula: 43 Ra I H-U - (XD in which U, R*, R and f have the meanings given above with respect to the formulae (II) and (V) (in the case where U = -0-, the starting material is an alcohol; in the case where U = -NR'-, the 5 starting material is an amino derivative of the cyclic amine); with a chlorosilane of formula (R) ty C) (XUI) ==-- CH-(Cjii)7Si-Cz() in which x, y and z have the meanings given above with respect to the formula (II). 10

13. As means for implementing the process according to claim 10, a novel unsaturated organic compound (*) of formula: (R) R 8 CH==CH-4CH2)-Si-- U N-R 9 C R8 L is j in which the symbols R, U, Re, R 9 , f, x, y and z have the meanings given above with respect to the 44 formulae (II) and (V).

14. Use of an effective amount of an optionally mixed polyorganosiloxane according to any one of claims 1 to 9, as stabilizers in combating 5 light, oxidative and thermal degradation of organic polymers.

15. Use according to claim 14, characterized in that the organic polymers to be stabilized are chosen from polyolefins, polyurethanes, polyamides, 10 polyesters, polycarbonates, polysulphones, polyethersulphones, polyetherketones, acrylic polymers, their copolymers and their mixtures.

16. Composition containing organic polymer stabilized against the harmful effects of heat and of 15 UV, characterized in that it comprises an organic polymer to be stabilized and an effective amount of at least one optionally mixed polyorganosiloxane compound according to any one of claims 1 to 9.

17. Composition according to claim 16, 20 characterized in that it comprises: - per 100 g of organic polymer to be stabilized, - an amount of optionally mixed polyorganosiloxane according to any one of claims 1 to 9 which introduces from 0.04 to 20 milliequivalents of sterically hindered 25 amine functional group(s).

18. Composition according to claim 16 or 17, characterized in that the organic polymers to be stabilized are chosen from polyolefins, polyurethanes, 45 polyamides, polyesters, polycarbonates, polysulphones, polyethersulphones, polyetherketones, acrylic polymers, their copolymers and their mixtures.