Production and use of new thermoplastic polyurethane elastomers based on polyether carbonate polyols
View Patent ↗The invention relates to a method for producing a thermoplastic polyurethane elastomer based on polyether carbonate polyols. The method comprises a first step, in which at least A) an organic diisocyanate and B) a polyol having a number-average molecular weight Mn>=500 and <=5000 g/mol are reacted to form an isocyanate-terminated prepolymer. In a second step, the prepolymer is reacted with C) one or more chain extenders having a molecular weight>=60 and <=490 g/mol and optionally D) a monofunctional chain stopper or E) an organic diisocyanate, wherein optionally at least F) one catalyst is used in the first and/or second step.; The molar ratio of the sum of the isocyanate groups from A) and, if applicable, E) to the sum of the groups reactive to isocyanate in B), C), and, if applicable, D) is >=0.9:1 and <=12:1, and component B) contains at least one polyether carbonate polyol, which can be obtained by adding carbon dioxide and alkylene oxides to H-functional starter substances. The invention further relates to a thermoplastic polyurethane elastomer produced in accordance with the method according to the invention, the use of said thermoplastic polyurethane elastomer to produce extruded or injection molded items, and the items produced by extrusion or injection molding.
1. A process for the production of an injection-molded or extruded item comprising preparing a thermoplastic polyurethane elastomer by reacting, in a reactive extruder, in a first step, at least
A) one organic diisocyanate comprising two isocyanate groups with
B) one polyol with number-average molar mass M n ≧500 and ≦5000 g/mol, which has two isocyanate-reactive groups,
to give an isocyanate-terminated prepolymer,
and reacting, in a second step, the prepolymer with
C) one or more chain extenders with molar mass ≧60 and ≦490 g/mol, which have two isocyanate-reactive groups,
and optionally
D) a monofunctional chain terminator which has an isocyanate-reactive group and/or optionally
E) an organic diisocyanate comprising two isocyanate groups,
where
F) a catalyst
is optionally used in the first and/or second step,
the molar ratio of the entirety of the isocyanate groups from A) and optionally E) to the entirety of the isocyanate-reactive groups in B), C), and optionally D) is ≧0.9:1 and >1.2:1 and
component B) comprises at least one polyether carbonate polyol obtainable via an addition reaction of carbon dioxide and a mixture of 75 to 100% by weight of propylene oxide and 0 to 25% by weight of ethylene oxide onto H-functional starter substances, and
injection molding or extruding the thermoplastic polyurethane elastomer to produce the injection-molded or extruded item.
2. The process as claimed in claim 1 , wherein in the second step the prepolymer is reacted only with
C) one or more chain extenders with molar mass ≧60 and ≦490 g/mol, which have two isocyanate-reactive groups,
and optionally
D) a monofunctional chain terminator which has an isocyanate-reactive group
and/or optionally
E) an organic diisocyanate comprising two isocyanate groups.
3. The process as claimed in claim 1 , wherein the polyether carbonate polyol is obtainable via an addition reaction of carbon dioxide and propylene oxides onto H-functional starter substances with the use of multimetal cyanide catalysts.
4. The process as claimed in claim 1 , wherein the content of carbonate groups, calculated as CO 2 in the polyether carbonate polyol is ≧3 and ≦35% by weight.
5. The process as claimed in claim 1 , wherein the number-average molar mass M n of the poly ether carbonate polyol is ≧500 and ≦10000 g/mol.
6. The process as claimed in claim 1 , wherein the average OH functionality of the polyether carbonate polyol is ≧1.85 and ≦2.5.
7. The process as claimed in claim 1 , wherein the organic diisocyanate A) comprises at least one aromatic diisocyanate.
8. The process as claimed in claim 1 , wherein component B) comprises at least one polyether carbonate polyol and at least one polyether polyol.
9. The process as claimed in claim 1 , wherein component B) comprises at least one polyether carbonate polyol and at least one polyester polyol.
10. The process as claimed in claim 1 , wherein component B) comprises at least one polyether carbonate polyol and at least one polycarbonate polyol.
11. The process as claimed in claim 1 , wherein component B) comprises two polyether carbonate polyols that differ from one another.
12. The process as claimed in claim 1 , wherein component C) comprises diols, diamines, or diol/diamine mixtures.
13. An injection-molded or extruded item obtained by the process as claimed in claim 1 .
14. The process as claimed in claim 1 , wherein the organic diisocyanate A) comprises at least one aromatic diisocyanate, wherein the content of carbonate groups, calculated as CO 2 in the polyether carbonate polyol is ≧3 and ≦35% by weight, and wherein component C) comprises a diol.
15. The process as claimed in claim 1 , wherein the molar ratio of the isocyanate groups from A) to the groups in B) reactive toward isocyanate is from 1.1:1 to 5:1.
16. The process as claimed in claim 1 , wherein the average OH functionality of the polyether carbonate polyol is ≧1.97 and ≦2.03.
17. The process as claimed in claim 1 , wherein the proportion ofpolyether carbonate polyols, based on the total mass of component B), is ≧20 and ≦100% by weight.