MASTIC FOR EXTREME WEATHER CONDITIONS IN TERMS OF TEMPERATURE AND HUMIDITY

1 - 13 . (canceled)

14 . A sealant composition comprising, on the basis of the total weight thereof:

from 20% to 45% by weight of a silyl polymer (A);

from 30% to 55% by weight of a filler (B); and

from 0.05% to 5% by weight of an antioxidant composition (C) consisting:

of a secondary diarylamine (C1) of formula (1), (1′) or (1″):

wherein:

X 1 , X 2 , X 3 and X 4 , which are identical or different, each represent a hydrogen atom or a radical having from 1 to 20 carbon atoms and chosen from alkyl, arylalkyl, aryl and alkylaryl; it being possible in addition for X 1 and X 2 or X 3 and X 4 to be respectively engaged in a ring; and

X 5 represents an oxygen or sulfur atom, or a —C(R)(R′)— divalent radical wherein R and R′, which are identical or different, are a hydrogen atom or an alkyl radical having from 1 to 30 carbon atoms; and

of a hindered phenol (C2) of formula (2):

 wherein:

X 6 and X 7 , which are identical or different, represent a linear or branched alkyl radical comprising from 1 to 7 carbon atoms, and

X 8 represents a linear, branched or cyclic alkyl radical comprising from 1 to 22 carbon atoms, with the optional presence of at least one heteroatom chosen from O or S or of a —COO— carbonyloxy function.

15 . The sealant composition as claimed in claim 14 , characterized in that the silyl polymer (A) is a polymer comprising at least one group of formula (I):

—Si(R 4 ) p (OR 5 ) 3-p   (I)

wherein:

R 4 represents a linear or branched alkyl radical comprising from 1 to 4 carbon atoms, with the possibility that when there are several R 4 radicals, these radicals are identical or different;

R 5 represents a linear or branched alkyl radical comprising from 1 to 4 carbon atoms, with the possibility that when there are several R 5 radicals, these radicals are identical or different, with the possibility that two OR 5 groups may be engaged in the same ring; and

p is an integer equal to 0, 1 or 2.

16 . The sealant composition as claimed in claim 14 , characterized in that the silyl polymer (A) corresponds to one of the formulae (II), (III) or (IV):

wherein:

R 4 , R 5 and p have the same meaning as in formula (I) described above,

P represents a saturated or unsaturated, linear or branched polymeric radical optionally comprising one or more heteroatoms, and having a number-average molar mass ranging from 100 g/mol to 48600 g/mol,

R 1 represents a divalent hydrocarbon radical comprising from 5 to 15 carbon atoms which can be aromatic or aliphatic and linear, branched or cyclic,

R 3 represents a linear or branched divalent alkylene radical comprising from 1 to 6 carbon atoms,

X represents a divalent radical chosen from —NH—, —NR 7 — or —S—,

R 7 represents a linear or branched alkyl radical comprising from 1 to 20 carbon atoms and which may also comprise one or more heteroatoms, and

f is an integer ranging from 1 to 6.

17 . The sealant composition as claimed in claim 16 , characterized in that the silyl polymer (A) corresponds to one of the formulae (II′), (III′) or (IV′):

wherein:

R 1 , R 3 , R 4 , R 5 , X, R 7 and p have the same meaning as in formulae (II), (III) and (IV),

R 2 represents a saturated or unsaturated, linear or branched divalent hydrocarbon radical optionally comprising one or more heteroatoms, and having a number-average molar mass ranging from 100 g/mol to 48600 g/mol, and

n is an integer greater than or equal to 0.

18 . The sealant composition as claimed in claim 17 , characterized in that the silyl polymer (A) is a polymer of formula (IV′) wherein:

R 1 is the divalent radical derived from isophorone diisocyanate (IPDI)

R 2 is derived from a polypropylene glycol, and

X is the —NR 7 radical.

19 . The sealant composition as claimed in claim 14 , characterized in that alkali metal or alkaline-earth metal carbonates are used as filler (B).

20 . The sealant composition as claimed in claim 14 , characterized in that the secondary diarylamine (C1) of formula (1), (1′) or (1″) is such that X 2 and X 4 each represent a hydrogen atom and X 1 and X 3 each represent an alkyl radical of 3 to 7 carbon atoms, substituted by a phenyl group.

21 . The sealant composition as claimed in claim 14 , characterized in that the hindered phenol (C2) of formula (2) is such that:

X 6 and X 7 represent a branched alkyl radical comprising from 3 to 4 carbon atoms, and

X 8 represents an alkyl radical comprising from 10 to 22 carbon atoms and comprising a carbonyloxy group.

22 . The sealant composition as claimed in claim 14 , characterized in that the antioxidant composition (C) consists, on the basis of the total number of moles of (C1) and (C2), of 20% to 80% of (C1) and from 20% to 80% of (C2).

23 . The sealant composition as claimed in claim 14 , characterized in that the antioxidant composition (C) consists, on the basis of the total number of moles of (C1) and (C2), of 20% to 40% of (C1) and from 60% to 80% of (C2).

24 . A process for assembling two substrates by adhesive bonding, comprising:

the coating, onto at least one of the two substrates to be assembled, of the sealant composition as defined in claim 14 ; then

effectively bringing the two substrates into contact.

25 . The process as claimed in claim 24 , characterized in that the substrates are chosen from inorganic substrates or organic substrates.

26 . The process as claimed in claim 25 , wherein the inorganic substrates comprise concrete, metals, or alloys.

27 . The process as claimed in claim 25 , wherein the organic substrates comprise wood or resins.