A single-component polyorganosiloxane composition (POS) which is stable on storage in the absence of moisture and which crosslinks in the presence of water to give a non-yellowing and adherent elastomer, said composition comprising:
- (i) at least one crosslinkable linear polyorganopolysiloxane A of formula:
- in which:
- the substituents R1, which may be identical or different, are each a saturated or unsaturated, substituted or unsubstituted, aliphatic, cyclanic or aromatic, C1 to C13 monovalent hydrocarbon radical;
- the substituents R2, which may be identical or different, are each a saturated or unsaturated, substituted or unsubstituted, aliphatic, cyclanic or aromatic, C1 to C13 monovalent hydrocarbon radical;
- the functionalization substituents Rfo, which may be identical or different, each represent:
- an iminoxy residue of formula:
- (R3)2C═N—O—
- wherein R3 independently is a linear or branched C1 to C8 alkyl radical, a C3 to C8 cycloalkyl radical or a C2-C8 alkenyl radical;
- an alkoxy residue of formula:
- R4O(CH2CH2O)b—
- wherein R4 independently is a linear or branched C1 to C8 alkyl radical or a C3 to C8 cycloalkyl radical and b=0 or 1;
- an acyloxy residue of formula:
- R5 is a saturated or unsaturated, substituted or unsubstituted, aliphatic, cyclanic or aromatic, C1 to C13 monovalent hydrocarbon radical;
- an epoxy residue of formula:
- (H)b′(R5)2−b′C═C(—O—)R5
- wherein R5 is as defined above and b′=0, 1 or 2;
- each symbol Y represents an oxygen atom or a divalent hydrocarbon radical;
- n has a value sufficient to confer, on the POS A, a dynamic viscosity at 25° C. ranging from 1000 to 1,000,000 mPa·s;
- a is zero or 1;
- (2i) optionally, at least one polyorganosiloxane resin B functionalized by at least one radical Rfo as defined above and having in its structure, at least two different siloxyl units selected from among those of formulae (R1)3SiO1/2 (M unit), (R1)2SiO2/2 (D unit), R1SiO3/2 (T unit) and SiO2 (Q unit), at least one of these units being a T or Q unit, the radicals R1, which may be identical or different, are as defined above with respect to the formula (I), said resin having a content by weight of functional radicals Rfo ranging from 0.1 to 10%, with the proviso that a portion of the radicals R1 are radicals Rfo;
- (3i) optionally, at least one crosslinking agent C of formula:
- (R2)aSi[Rfo]4−a (II)
- wherein R2, Rfo and a are as defined above;
- (4i) optionally, a residual amount of the functionalization catalyst D in the presence of which the preparation of the POS(s) A and of the optional resin(s) B which are functionalized by Rfo occurs;
- (5i) optionally, at least one primary aliphatic C1 to C3 alcohol E;
- (6i) optionally, at least one unreactive linear polydiorganosiloxane F which is not functionalized by Rfo and which has the formula:
- in which:
- the substituents R1, which may be identical or different, are as defined above for the polyorganosiloxane A of formula (I);
- m has a value sufficient to confer, on the polymer of formula (III), a dynamic viscosity at 25° C. ranging from 10 to 200,000 mPa·s;
- (7i) at least one inorganic filler G;
- (8i) optionally, at least one auxiliary agent H;
- (9i) an effective amount of a crosslinking/curing catalyst I;
- said composition further comprising the following parameters (α), (β) and (γ):
- (α) the curing catalyst I comprises the combination of at least one organic derivative I1 of a metal M1 selected from among titanium, zirconium and mixtures thereof with at least one organic derivative 12 of a metal M2 selected from among zinc, aluminum, boron, bismuth and mixtures thereof;
- (β) the number of μg.at (microgram atoms) of the metals M1+M2 introduced into 1 g of single-component composition comprising all the ingredients (i) to (8i) is within the range from 1 to 150;
- (γ) the ratio:
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- is within the range from 5 to 95%.