Heat curable adhesive composition

1. A heat-curable adhesive composition comprising:

from 20 to 85% of a polyether (A) comprising 2 hydrolysable alkoxysilane-type end groups, having a viscosity, measured at 23° C., ranging from 25 to 40 Pa·s and of formula (I):

in which:

R 1 and R 2 , which are identical or different, each represent a linear or branched alkyl radical having 1 to 4 carbon atoms, with the possibility, when there are several R 1 (or R 2 ) radicals, that these are identical or different;

R 3 represents a linear alkylene divalent radical comprising from 1 to 6 carbon atoms;

R 4 represents a linear or branched alkylene divalent radical comprising from 1 to 4 carbon atoms;

n is an integer such that the number-average molecular weight M n of the polymer of formula (I) is between 20 kDa and 40 kDa;

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

from 15 to 80% of a compatible tackifying resin (B), having a number-average molecular weight between 200 Da and 10 kDa; and

from 0.01 to 3% of a curing catalyst (C).

2. The adhesive composition according to claim 1 , wherein the polyether (A) of formula (I) has one and/or the other of the following features:

R 1 and R 2 , which are identical or different, each represent a methyl or ethyl radical;

R 3 represents a linear alkylene divalent radical comprising from 1 to 3 carbon atoms;

R 4 is chosen from the divalent radicals: ethylene, isopropylene, n-propylene, n-butylene, ethyl-ethylene.

3. The adhesive Adhesive composition according to claim 1 , wherein the polyether (A) of formula (I) is such that:

p=0 or 1;

R 1 and R 2 each represent the methyl radical; and

R 4 is an alkylene radical having 3 carbon atoms.

4. The adhesive composition according to claim 1 , wherein the polyether (A) of formula (I) is such that its number-average molecular weight varies from 30 to 40 kDa and its viscosity from 30 to 37 Pa·s.

5. The adhesive composition according to claim 1 , wherein the polyether (A) of formula (I) has a polydispersity index ranging from 1 to 2.

6. The adhesive composition according to claim 1 , wherein the resin (B) is:

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

(ii) a resin obtained by a process comprising the polymerization of α-methylstyrene;

(iii) a natural or modified rosin, optionally hydrogenated, dimerized, polymerized or esterified by monoalcohols or polyols;

(iv) a resin obtained by hydrogenation, polymerization or copolymerization of mixtures of unsaturated aliphatic hydrocarbons having around 5, 9 or 10 carbon atoms derived from petroleum fractions;

(v) a terpene resin;

(vi) a copolymer based on natural terpenes; or

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

7. The adhesive composition according to claim 6 , wherein the resin (B) is a resin of type (i) or (ii).

8. The adhesive composition according to claim 6 , wherein the resin (B) is a resin of type (iii).

9. The adhesive composition according to claim 1 , comprising from 40 to 65% of polyether (A) of formula (I) and from 35 to 60% of tackifying resin(s) (B).

10. The adhesive composition according to claim 1 , comprising up to 3% of a hydrolysable alkoxysilane derivative, as a desiccant.

11. A self-adhesive support capable of being obtained by a process comprising:

(a) preheating the adhesive composition as defined in claim 1 to a temperature between 50 and 130° C.; then

(b) coating it onto a support layer; then

(c) curing it, by heating the thus coated support at a temperature between 50 and 150° C.

12. Single-sided or double-sided self-adhesive labels and/or tapes comprising the self-adhesive support as defined in claim 11 .