Polyether alcohols and method for the production of polyether alcohols for polyurethane synthesis
The invention relates to polyether alcohols, to a process for preparing polyether alcohols by reacting alkylene oxides in the presence of a double metal cyanide (DMC) catalyst with at least one saturated OH component which may, if appropriate, have previously been reacted with an alkylene oxide, wherein an antioxidant is added before or during the reaction, and also to the further processing of the polyether alcohols to form polyurethanes.
1. A process for preparing a polyether alcohol component, which is at least one polyether alcohol, comprising reacting at least one saturated alkylene oxide with (1) at least one saturated OH compound, or (2) an alkylene oxide that has previously been oligomerized or polymerized with the saturated OH compound, in the presence of a double metal cyanide (DMC) catalyst, wherein at least one antioxidant is added before the reaction, using more antioxidant than DMC catalyst (based on the mass of DMC catalyst used), wherein the amount of antioxidant is from 2 to 500 times the mass of catalyst used.
2. The process according to claim 1 , wherein the antioxidant is selected from the group consisting of sterically hindered phenols, N,N-disubstituted hydroxylamines, sterically hindered secondary cyclic amines, diarylamines, organic phosphonic acid derivatives, N,N-substituted hydrazine compounds, oxamide compounds, benzofurans and lactones.
3. The process according to claim 1 , wherein the antioxidant is used in a concentration of from 7 to 4000 ppm, based on the mass of polyether alcohol component to be prepared.
4. The process according to claim 1 , wherein the antioxidant is added immediately before one of the following process steps (a) to (g): (a) addition of the OH compound, (b) addition of the DMC catalyst, (c) milling of the DMC catalyst, (d) removal of suspension media, (e) removal of water, (f) addition of alkylene oxide, and (g) reaction of alkylene oxide with OH compound.
5. The process according to claim 1 , wherein the amount of double metal cyanide catalyst is from 5 to 1000 ppm, based on the mass of the polyether alcohol component to be prepared.
6. The process according to claim 1 , wherein the polyether alcohol component has a hydroxyl number of from 10 to 350 mg KOH/g.
7. The process according to claim 1 , wherein the polyether alcohol component has an OH functionality of from 1 to 8.
8. A polyether alcohol prepared by a process according to claim 1 , having an OH functionality of from 1 to 8, a hydroxyl number of from 30 to 300 mg KOH/g, and a DMC catalyst concentration of from 10 to 1000 ppm and further comprising an antioxidant in an amount that is from 2 to 500 times the mass of the DMC catalyst.
9. A process for producing polyurethanes, comprising the following steps:
A) preparing a polyether alcohol component by a process according to claim 1 , and
B) reacting the polyether alcohol component from step A) with one or more isocyanates and/or polyisocyanates to form polyurethanes.
10. The process according to claim 1 , wherein at least one saturated alkylene oxide is reacted with (1) said at least one saturated OH compound.
11. The process according to claim 1 , wherein at least one saturated alkylene oxide is reacted with (2) said alkylene oxide that has previously been oligomerized or polymerized with the saturated OH compound.
12. The process according to claim 1 , wherein the amount of antioxidant is from 2 to 10 times the mass of catalyst used.
13. The process according to claim 1 , wherein the amount of antioxidant is from 2 to 13⅓ times the mass of catalyst used.
14. The process according to claim 1 , wherein the amount of antioxidant is from 2 to 3⅓ times the mass of catalyst used.
15. The process according to claim 1 , wherein the amount of antioxidant is from 2 to 6⅔ times the mass of catalyst used.
16. The process according to claim 7 , wherein the polyether alcohol component has an OH functionality of from 2 to 6.
17. The process according to claim 5 , wherein the amount of double metal cyanide catalyst is from 10 to 500 ppm, based on the mass of the polyether alcohol component to be prepared.
18. The process according to claim 5 , wherein the amount of double metal cyanide catalyst is from 25 to 150 ppm, based on the mass of the polyether alcohol component to be prepared.
19. The process according to claim 1 , wherein the antioxidant is used in a concentration of from 50 to 1000 ppm, based on the mass of polyether alcohol component to be prepared.
20. The process according to claim 1 , wherein the antioxidant is selected from the group consisting of BHT, alpha-tocopherol, dihexadecylhydroxylamine, triphenyl phosphite and diphenyloxamide.