AQUEOUS DISPERSION OF POLYURETHANE
The present invention concerns an aqueous dispersion comprising water and a mixture of: A) an aqueous dispersion comprising water and a polyurethane polymer A-1) obtained by reacting at least the following components: (a) a polyisocyanate compound; (b) a polyol compound comprising: (c) an emulsifier; B) an aqueous dispersion other than A) comprising water and a polyurethane polymer B-1) obtained by reacting at least the following components: (i) a diisocyanate; (ii) at least one polyether polyol having a number average molecular weight (Mn) ranging from 500 to 10 000 g/mol; (iii) an amino compound having an amino functionality higher or equal to 1; (iv) a compound comprising at least one isocyanate-reactive group and at least one ionic or potentially ionic group; wherein said polyurethane B-1) is amorphous.
1 - 19 . (canceled)
20 . An aqueous dispersion comprising water and a mixture of:
A. an aqueous dispersion comprising water and a polyurethane polymer A-1) obtained by reacting at least the following components:
a) a polyisocyanate compound;
b) a polyol compound comprising:
(b1) a mixture of a polyester polyol (b2) and of a polycarbonate polyol (b3), each having a number-average molecular weight (Mn) higher or equal to 500 g/mol;
(b4) a polyester-polycarbonate polyol having a number-average molecular weight (Mn) higher or equal to 500 g/mol; or
(b5) a mixture of a polyester-polycarbonate polyol (b4) as defined above and at least one polyol selected from polyester polyol (b2) as defined above, polycarbonate polyol (b3) as defined above, and mixtures thereof;
provided that in the polyol compound b), the molar ratio —C(═O)—O—/—O—C(═O)—O— ranges from 35/65 to 75/25;
c) an emulsifier;
d) an optional compound comprising at least one isocyanate-reactive group and at least one ionic or potentially ionic group;
e) an optional compound comprising at least one isocyanate-reactive group and at least one non-ionic hydrophilic group;
f) an optional amino compound having an amino functionality higher or equal to 1;
g) an optional diol having a molecular weight lower than 400 g/mol; and
B. an aqueous dispersion other than A) comprising water and a polyurethane polymer B-1) obtained by reacting at least the following components:
(i) a diisocyanate;
(ii) at least one polyether polyol having a number average molecular weight (Mn) ranging from 500 to 10,000 g/mol;
(iii) an amino compound having an amino functionality higher or equal to 1;
(iv) a compound comprising at least one isocyanate-reactive group and at least one ionic or potentially ionic group;
wherein said polyurethane B-1) is amorphous.
21 . The aqueous dispersion according to claim 20 , characterized in that the polyisocyanate compound (a) comprises hexamethylene diisocyanate, wherein the amount of hexamethylene diisocyanate is not less than 25 wt. % based on that the amount of the polyisocyanate compound (a) is 100 wt. %.
22 . The aqueous dispersion according to claim 20 , characterized in that the polyisocyanate compound (a) further comprises a polyisocyanate (a-1) other than the hexamethylene diisocyanate.
23 . The aqueous dispersion according to claim 22 , wherein the polyisocyanate compound (a-1) is isophorone diisocyanate.
24 . The aqueous dispersion according to claim 20 , characterized in that in the polyol compound b), the molar ratio —C(═O)—O—/—O—C(═O)—O— ranges from 35/65 to 75/25.
25 . The aqueous dispersion according to claim 20 , characterized in that the polyester polyol (b2) has a number-average molecular mass (Mn) ranging from 500 g/mol to 10 000 g/mol.
26 . The aqueous dispersion according to claim 20 , characterized in that the polyester polyol (b2) is a polyester polyol resulting from the polycondensation of adipic acid and an aliphatic polyol.
27 . The aqueous dispersion according to claim 20 , characterized in that the polycarbonate polyol (b3) is obtained by reaction of at least a carbonate compound and a diol, optionally in presence of a catalyst.
28 . The aqueous dispersion according to claim 20 , characterized in that the polyurethane A-1) has an enthalpy of fusion ranging from 15 J/g to 60 J/g.
29 . The aqueous dispersion according to claim 20 , characterized in that the polyurethane A-1) has a glass transition temperature in the range between −100° C. and −10° C.
30 . The aqueous dispersion according to claim 20 , characterized in that the diisocyanate (ii) is selected from the group consisting of 2,4-toluylene diisocyanate (2,4-TDI), 2,6-toluylene diisocyanate (2,6-TDI), isophorone diisocyanate (IPDI), 1,4-xylylene diisocyanate (XDI), and mixtures thereof.
31 . The aqueous dispersion according to claim 20 , characterized in that the polyether polyol (ii) is chosen from polyoxyalkylene polyols, the linear or branched alkylene part comprising from 1 to 4 carbon atoms.
32 . The aqueous dispersion according to claim 20 , characterized in that the component (iv) is selected from the group consisting of the sodium salts of N-(2-aminoethyl)-P-alanine, the sodium salts of 2-(2-aminoethylamino)ethanesulfonic acid and dimethylolpropionic acid.
33 . The aqueous dispersion according to claim 20 , characterized in that the polyurethane B-1) is an anionic polyurethane comprising at least one anionic group.
34 . The aqueous dispersion according to claim 20 , characterized in that the polyurethane B-1) has a glass transition temperature Tg ranging from −60° C. to 0° C.
35 . The aqueous dispersion according to claim 20 , characterized in that it comprises:
from 30 wt % to 90 wt %, of dispersion A), and
from 10 wt % to 70 wt % of dispersion B),
based on the total weight of said aqueous dispersion.
36 . A composition comprising the aqueous dispersion as defined in claim 20 .
37 . A method of assembling two substrates by bonding, comprising:
the application of the aqueous dispersion as defined in claim 20 on at least one substrate;
the evaporation of water;
an optional step of heating the adhesive layer formed on one surface of the substrate to a temperature Ti; and
the contact bonding of the two substrates.