Liquid composition for a waterproofing membrane

1. A liquid composition comprising a composition A and a composition B, said composition A comprising:

A1) from 20% to 80% by weight of at least one silylated polymer comprising at least one, group of formula (I):

—Si(R 4 ) p (OR 5 ) 3-p   (I)

wherein:

R 4 and R 5 , which are identical or different, each represent a linear or branched alkyl radical comprising from 1 to 4 carbon atoms, with the possibility that when there are several R 4 (or R 5 ) radicals, the latter are identical or different;

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

A2) from 3% to 9% by weight of a mixture of at least two different aromatic-based catalysts (A2-1) and (A2-2), the catalyst (A2-1) being phenolic, substituted by at least one —(CH 2 )—N(R 7 R 8 ) function, where R 7 and R 8 represent, independently of one another, a linear or branched alkyl radical comprising from 1 to 4 carbon atoms;

A3) from 0.1% to 2% by weight of at least one coupling agent for coupling between the silylated polymer present in the composition A and the epoxy resin present in the composition B;

and said composition B comprising:

B1) from 10% to 40% by weight of at least one epoxy resin;

B2) from 0.2% to 3% by weight of at least one silanol condensation catalyst;

the percentages by weight being expressed relative to the total weight of the liquid composition, the mixture of at least two catalysts (A2-1) and (A2-2) being chosen so that the following two relationships are respected:

(1) 48.00 meq/g≤Φ(OH)+Φ(CH 2 —NR 7 R 8 )≤90.00 meq/g

(2) 0.10≤Φ(OH)/Φ(CH 2 —NR 7 R 8 )≤0.33

in said relationships (1) and (2):

Φ(OH) represents the number of —OH functions borne by an aromatic ring expressed in milliequivalents per gram of liquid composition;

Φ(CH 2 —NR 7 R 8 ) represents the number of —CH 2 —NR 7 R 8 functions borne by an aromatic ring expressed in milliequivalents per gram of liquid composition.

2. The liquid composition as claimed in claim 1 , wherein the silylated polymer corresponds to one of the formulae (II), (III) or (IV):

wherein:

R 1 represents a hydrocarbon-based divalent radical having 5 to 15 carbon atoms, which may be aromatic or aliphatic, linear, branched or cyclic,

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

R 2 represents a linear or branched alkylene divalent radical having 2 to 4 carbon atoms,

R 4 and R 5 , which are identical or different, each represent a linear or branched alkyl radical having 1 to 4 carbon atoms,

R 6 represents a hydrogen atom, a phenyl radical or a linear, branched or cyclic alkyl radical having 1 to 6 carbon atoms,

n is an integer such that the average molar mass of the polyether block of formula —[OR 2 ] n -ranges from 200 g/mol to 40,000 g/mol,

m 1 is zero or an integer such that the average molar mass of the polymer ranges from 500 g/mol to 50,000 g/mol,

m is an integer other than zero such that the average molar mass of the polymer ranges from 500 g/mol to 50,000 g/mol,

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

3. The liquid composition as claimed in claim 1 , wherein the catalyst (A2-1) comprises at least one phenolic ring substituted by at least two —(CH 2 )—N(CH 3 ) 2 functions.

4. The liquid composition according to claim 3 , wherein the two —(CH 2 )—N(CH 3 ) 2 functions are in the ortho position to the OH group.

5. The liquid composition as claimed in claim 1 , wherein the catalyst (A2-1) is:

6. The liquid composition according to claim 5 , wherein (A2-1) is tri(dimethylaminomethyl)phenol corresponding to the following formula:

7. The liquid composition as claimed in claim 1 , wherein the catalyst (A2-2) different from the catalyst (A2-1) is an aromatic compound comprising at least one hydroxyl function or at least one —(CH 2 )—N(CH 3 ) 2 function.

8. The liquid composition as claimed in claim 1 , wherein the catalyst (A2-2) is:

9. The liquid composition according to claim 8 , wherein the catalyst (A2-2) is one of the following:

10. The liquid composition according to claim 8 , wherein the catalyst (A2-2) is the dimethylbenzylamine compound of the formula

11. The liquid composition as claimed in claim 1 , wherein (A2) comprises a mixture of 2,4,6-tri(dimethylaminomethyl)phenol as catalyst (A2-1) and of dimethylbenzylamine as catalyst (A2-2).

12. The liquid composition as claimed in claim 1 , wherein the following two relationships are respected:

(1) 50.00 meq/g≤Φ(OH)+Φ(CH 2 —NR 7 R 8 )≤90.00 meq/g

(2) 0.10≤Φ(OH)/Φ(CH 2 —NR 7 R 8 )≤0.30

in said relationships (1) and (2):

Φ(OH) represents the number of —OH functions borne by an aromatic ring expressed in milliequivalents per gram of liquid composition;

Φ((CH 2 )—N(R 7 R 8 ) 2 ) represents the number of —CH 2 —NR 7 R 8 functions borne by an aromatic ring expressed in milliequivalents per gram of liquid composition.

13. The liquid composition as claimed in claim 1 , wherein the epoxy resin (B1) is derived from diglycidyl ether.

14. The liquid composition as claimed in claim 1 , wherein the coupling agent (A3) is a bifunctional compound comprising at least one first function capable of reacting with the silylated polymer (A1) and one second function capable of reacting with the epoxy resin (B1).

15. A ready-to-use kit comprising the liquid composition as claimed in claim 1 , the compositions A and B being packaged in two separate compartments.

16. A waterproofing membrane obtained by crosslinking the liquid composition as claimed in claim 1 .

17. A surface coated with a membrane as claimed in claim 16 .

18. A process for waterproofing a surface, said process comprising the application then the crosslinking of the liquid composition as claimed in claim 1 on said surface.

19. The liquid composition according to claim 1 , wherein A2) contains at least two groups of formula I.