NOVEL CROSSLINKABLE COMPOSITION WITH A SILYL TERMINATED POLYMER, AND CORRESPONDING SELF-ADHESIVE ARTICLE

1 . A crosslinkable adhesive composition, characterized in that it comprises:

at least one polymer (A) comprising a hydrolyzable alkoxysilane group;

at least one tackifying resin (B);

at least one pyrogenic silica (C);

at least one crosslinking catalyst (D); and

a silsesquioxane resin (E).

2 . The adhesive composition as claimed in claim 1 , characterized in that the polymer (A) comprises at least one, hydrolyzable group of formula (I):

Si(R 4 ) p (OR 5 ) 3-p   (I)

in which:

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 can participate in one and the same ring; and

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

3 . The adhesive composition as claimed in claim 2 , characterized in that the polymer (A) corresponds to one of the formulae (II), (III) or (IV):

in which:

P represents a saturated or unsaturated, linear or branched, polymeric radical optionally comprising one or more heteroatoms, such as oxygen, nitrogen, sulfur or silicon, and,

R 1 represents a divalent hydrocarbon radical comprising from 5 to 15 carbon atoms which can be aromatic or aliphatic, 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 can also comprise one or more heteroatoms, and

f is an integer ranging from 1 to 6.

4 . The adhesive composition as claimed in claim 3 , characterized in that the polymer (A) corresponds to one of the formulae (II′), (III′) or (IV′):

in which:

R 2 represents a saturated or unsaturated, linear or branched, divalent hydrocarbon radical optionally comprising one or more heteroatoms, such as oxygen, nitrogen, sulfur or silicon, and

n is an integer greater than or equal to 0.

5 . The adhesive composition as claimed in claim 1 , characterized in that the tackifying resin (B) is chosen from:

(i) resins obtained by polymerization of terpene hydrocarbons and of phenols, in the presence of Friedel-Crafts catalysts;

(ii) resins obtained by a process comprising the polymerization of α-methylstyrene, it also being possible for said process to comprise a reaction with phenols;

(iii) rosins of natural origin or modified rosins;

(iv) resins obtained by hydrogenation, polymerization or copolymerization of mixtures of unsaturated aliphatic hydrocarbons having approximately 5, 9 or 10 carbon atoms resulting from petroleum fractions;

(v) terpene resins;

(vi) copolymers based on natural terpenes; or else

(vii) acrylic resins having a viscosity at 100° C. of less than 100 Pa·s.

6 . The adhesive composition as claimed in claim 1 , characterized in that the pyrogenic silica (C) is hydrophobic.

7 . The adhesive composition as claimed in claim 6 , characterized in that the hydrophobic pyrogenic silica (C) is obtained by treatment of a pyrogenic silica with a polydimethylsiloxane.

8 . The adhesive composition as claimed in claim 1 , characterized in that the pyrogenic silica (C) has a BET specific surface of at least 10 m 2 /g.

9 . The adhesive composition as claimed in claim 1 , characterized in that the silsesquioxane resin (E) corresponds to the following general formula (V):

in which each of R′ 1 to R′ 8 represents, independently of one another, a group chosen from:

a hydrogen atom,

a radical chosen from the group consisting of a linear or branched C 1 -C 4 alkoxy radical, a linear or branched alkyl radical comprising from 1 to 30 carbon atoms, an alkenyl radical comprising from 2 to 30 carbon atoms, an aromatic radical comprising from 6 to 30 carbon atoms, an allyl radical comprising from 3 to 30 carbon atoms, a cyclic aliphatic radical comprising from 3 to 30 carbon atoms and an acyl radical comprising from 1 to 30 carbon atoms, and

an —OSiR′ 9 R′ 10 group in which R′ 9 and R′ 10 each represents, independently of each other, a hydrogen atom or a radical chosen from the group consisting of linear or branched C 1 -C 4 alkyls, linear or branched C 1 -C 4 alkoxys, C 2 -C 4 alkenyls, a phenyl, a C 3 -C 6 allyl radical, a cyclic C 3 -C 8 aliphatic radical and a C 1 -C 4 acyl radical;

provided:

that at least one radical among the R′ 1 to R′ 8 radicals is a C 1 -C 4 alkoxy radical; and

that at least one radical among the R′ 1 to R′ 8 radicals is a phenyl radical.

10 . The adhesive composition as claimed in claim 1 , characterized in that it comprises:

from 3% to 90% by weight of at least one polymer (A);

from 8% to 80% by weight of at least one tackifying resin (B);

from 1% to 10% by weight of the pyrogenic silica (C);

from 0.01% to 10% by weight of crosslinking catalyst (D); and

from 0.1% to 20% by weight of silsesquioxane resin (E);

these percentages by weight being indicated on the basis of the total weight of said composition.

11 . A self-adhesive article comprising a support layer coated with a self-adhesive layer, characterized in that said self-adhesive layer consists of the adhesive composition as defined in claim 1 in the crosslinked state.

12 . A process for the manufacture of the self-adhesive article as defined in claim 11 , characterized in that it comprises:

(a) the application of said adhesive composition by coating onto a carrying surface;

(b) the crosslinking of said adhesive composition to form a layer, by heating at a temperature ranging from 15° C. to 200° C.; and then

(c) the lamination or the transfer of the layer of crosslinked adhesive composition onto a support layer or onto a nonstick protective film.

13 . The process for the manufacture of the self-adhesive article as claimed in claim 12 , characterized in that the crosslinking stage b) is carried out at a temperature ranging from 15° C. to 45° C.

14 . An adhesive bonding method employing the self-adhesive article as defined in claim 11 , characterized in that it comprises the following stages:

a) the removal of the nonstick protective layer, when such a layer is present;

b) the application of the self-adhesive article to a surface of a product; and

c) the application of a pressure to said article.