METHOD FOR PREPARING A POLYURETHANE POLYMER
The invention relates to a method for preparing a polyurethane polymer, comprising: (A) contacting of at least one isophorone diisocyanate (IPDI) monomer with at least one first polyol in the presence of at least one first catalyst; (B) contacting of the urethane prepolymer with at least one second polyol in the presence of at least one second catalyst to form the polyurethane polymer, wherein the first catalyst is a guanidine-type catalyst and the second catalyst is an (organo) metallic catalyst or wherein the first catalyst is an (organo) metallic catalyst and the second catalyst is a guanidine-type catalyst. The invention relates also to a two-component composition and to the use thereof as an adhesive for bonding two substrates together. Lastly, the invention relates to an article comprising at least one layer obtained by crosslinking of said composition and to a method for preparing said article.
1 . A method for preparing a polyurethane polymer, comprising
(A) contacting of at least one isophorone diisocyanate (IPDI) monomer with at least one first polyol in the presence of at least one first catalyst to form a urethane prepolymer;
(B) contacting of the urethane prepolymer with at least one second polyol in the presence of at least one second catalyst to form the polyurethane polymer;
wherein:
the first catalyst is selected from a catalyst of the general formula (I) or a catalyst of the general formula (II):
wherein:
R 0 is a group containing from 1 to 10 carbon atoms, selected from an alkyl group, either linear or branched, or a cycloalkyl or arylalkyl group,
R 1 , R 2 , and R 3 each independently represent a group containing from 1 to 10 carbon atoms, selected from an alkyl group, either linear or branched, or a cycloalkyl or arylalkyl group,
R 4 represents a hydrogen atom or a group containing from 1 to 10 carbon atoms, selected from an alkyl group, either linear or branched, or a cycloalkyl or arylalkyl group,
at least two of R 1 , R 2 , R 3 , and R 4 being optionally elements of a ring, and
M + represents a monovalent cation; and
the second catalyst is an (organic)metallic catalyst;
or wherein:
the first catalyst is an (organic)metallic catalyst; and
the second catalyst is selected from a catalyst of the general formula (I) or a catalyst of the general formula (II).
2 . The method as claimed in claim 1 , wherein the first catalyst is selected from a catalyst of the general formula (I) or a catalyst of the general formula (II) and the second catalyst is an (organic)metallic catalyst.
3 . The method as claimed in claim 1 or 2 , wherein the first and/or the second polyol is selected from polyether polyols, polyester polyols, and mixtures thereof, and preferably the first and/or the second polyol comprises a polypropylene glycol.
4 . The method as claimed in one of claims 1 to 3 , wherein the second polyol is the same as the first polyol.
5 . The method as claimed in one of claims 1 to 4 , wherein M + represents a Na + cation.
6 . The method as claimed in one of claims 1 to 5 , wherein R 0 is selected from a methyl group or a benzyl group.
7 . The method as claimed in one of claims 1 to 6 , wherein R 1 and R 2 or R 1 and R 4 are elements of a ring.
8 . The method as claimed in one of claims 1 to 6 , wherein R 1 and R 2 are elements of a first ring and R 3 and R 4 are elements of a second ring.
9 . The method as claimed in one of claims 1 to 8 , wherein the (organic)metallic catalyst is selected from a tin catalyst, a zinc catalyst, a bismuth catalyst, a titanium catalyst, an iron catalyst, a copper catalyst, a zirconium catalyst, an aluminum catalyst, and combinations thereof, and the (organic)metallic catalyst is preferably selected from a zinc catalyst, a bismuth catalyst, a titanium catalyst, an iron catalyst, a copper catalyst, an aluminum catalyst, and a zirconium catalyst.
10 . The method as claimed in one of claims 1 to 9 , wherein, in the step of contacting at least one isophorone diisocyanate (IPDI) monomer with at least one first polyol, the NCO/OH molar ratio is between 1.5 and 5, preferably between 1.5 and 4, preferably between 1.5 and 3, and more preferably between 1.5 and 2.
11 . A two-component composition for preparing a polyurethane polymer according to the method as claimed in one of claims 1 to 10 , the composition comprising:
an NCO component comprising the urethane prepolymer prepared by step (A) of the method;
and an OH component comprising at least a second polyol and the second catalyst.
12 . The composition as claimed in claim 11 , wherein the NCO component also comprises one or more additives selected from plasticizers, solvents, pigments, adhesion promoters, moisture absorbers, UV stabilizers (or antioxidants), fluorescent materials, rheological additives, and mixtures thereof.
13 . The composition as claimed in one of claim 11 or 12 , wherein the NCO/OH molar ratio of the NCO component to the OH component is from 1.5 to 2.5, and preferably from 1.7 to 2.0.
14 . The use of the composition as claimed in one of claims 11 to 13 as an adhesive for bonding two substrates together.
15 . An article comprising at least one layer obtained by crosslinking of the composition as claimed in one of claims 11 to 13 .
16 . A method for preparing the article as claimed in claim 15 , comprising:
mixing of the NCO component with the OH component of the composition;
coating of this mixture onto the surface of a substrate; and
contacting of this surface with the surface of an additional substrate.