Low-viscosity polymer polyols characterized by a high hydroxyl number
View Patent ↗The present invention relates to novel polymer polyols which have low viscosities and high hydroxyl numbers, and to a process for the preparation of these novel polymer polyols. These polymer polyols have hydroxyl numbers of ≧20, solids contents of about 30 to about 65% by weight and a viscosity that is less than or equal to: be [2.7c] . These comprise the reaction product of a base polyol, a preformed stabilizer and at least one ethylenically unsaturated monomer, in the presence of a free-radical polymerization initiator and at least one polymer control agent. The base polyol has a hydroxyl number of 60 to 1900, a functionality of 1 to 10, and an equivalent weight of 30 to 900.
1. A stable, low-viscosity polymer polyol having a hydroxyl number of ≧20, a viscosity that is less than or equal to:
be [2.7c]
wherein:
b represents the base polyol viscosity,
and
c represents [wt. % solids in polymer polyol/(100−wt. % solids in polymer polyol)],
having a solids content of 30% to 65% by weight, based on the total weight of the polymer polyol, comprising the reaction product of:
(A) a base polyol having a hydroxyl number of from 60 to 1900, a functionality of 1 to 10, and an equivalent weight of 30 to 900,
(B) a preformed stabilizer,
and
(C) at least one ethylenically unsaturated monomer,
in the presence of
(D) a free-radical polymerization initiator,
and
(E) at least one polymer control agent.
2. The stable, low-viscosity polymer polyol of claim 1 which is characterized by a hydroxyl number of at least 35.
3. The stable, low-viscosity polymer polyol of claim 1 , wherein (A) said base polyol has a hydroxyl number of from 70 to 600, a functionality of 2 to 6, and an equivalent weight of from 100 to 600.
4. The stable, low-viscosity polymer polyol of claim 1 , wherein (A) said base polyol has an OH number of 90 to 400, a functionality of 2 to 3, and an equivalent weight of 200 to 500.
5. The stable, low-viscosity polymer polyol of claim 1 , wherein (C) said ethylenically unsaturated monomer comprises a mixture of styrene and acrylonitrile.
6. The stable, low-viscosity polymer polyol of claim 1 , wherein styrene and acrylonitrile are present in a weight ratio of from 80:20 to 40:60.
7. The stable, low-viscosity polymer polyol of claim 1 , wherein (D) said free-radical polymerization initiator is selected from the group consisting of azo compounds, peroxide compounds and mixtures thereof.
8. The stable, low-viscosity polymer polyol of claim 7 , wherein said azo compounds are selected from the group consisting of azobis(isobutyronitrile), 2,2′-azo bis(2-methylbutyronitrile) and mixtures thereof.
9. The stable, low-viscosity polymer polyol of claim 7 , wherein said peroxide compounds are selected from the group consisting of acyl peroxides, alkyl peroxides and mixtures thereof.
10. The stable, low-viscosity polymer polyol of claim 1 , wherein said polymer control agent comprises one or more alcohols containing at least one carbon atom.
11. The stable, low-viscosity polymer polyol of claim 10 , wherein said polymer control agent comprises isopropanol.
12. The stable, low-viscosity polymer polyol of claim 1 which is characterized by a hydroxyl number of at least 50.
13. A process for preparing a stable, low-viscosity polymer polyol having a hydroxyl number of ≧20, a viscosity that is less than or equal to:
be [2.7c]
wherein:
b represents the base polyol viscosity,
and
c represents [wt. % solids in polymer polyol/(100−wt. % solids in polymer polyol)],
and a solids content of 30% to 65% by weight, based on the total weight of the polymer polyol, comprising
(1) reacting:
(A) a base polyol having a hydroxyl number of from 60 to 1900, a functionality of 1 to 10, and an equivalent weight of 30 to 900,
(B) a preformed stabilizer,
and
(C) at least one ethylenically unsaturated monomer,
in the presence of
(D) a free-radical polymerization initiator,
and
(E) at least one polymer control agent.
14. The process of claim 13 in which the stable, low-viscosity polymer polyol is characterized by a hydroxyl number of at least 35.
15. The process of claim 13 , wherein (A) said base polyol has a hydroxyl number of from 70 to 600, a functionality of 2 to 6, and an equivalent weight of from 100 to 600.
16. The process of claim 13 , wherein (A) said base polyol has an OH number of 90 to 400, a functionality of 2 to 3, and an equivalent weight of 200 to 500.
17. The process of claim 13 , (C) said ethylenically unsaturated monomer comprises a mixture of styrene and acrylonitrile.
18. The process of claim 17 , wherein styrene and acrylonitrile are present in a weight ratio of from 80:20 to 40:60.
19. The process of claim 13 , wherein (D) said free-radical polymerization initiator is selected from the group consisting of azo compounds, peroxide compounds and mixtures thereof.
20. The process of claim 19 , wherein said azo compounds are selected from the group consisting of azobis(isobutyronitrile), 2,2′-azo bis(2-methylbutyronitrile) and mixtures thereof.
21. The process of claim 19 , wherein said peroxide compounds are selected from the group consisting of acyl peroxides, alkyl peroxides, persulfates, perborates, percarbonates and mixtures thereof.
22. The process of claim 13 , wherein said polymer control agent comprises one or more alcohols containing at least one carbon atom.
23. The process of claim 22 , wherein said polymer control agent comprises isopropanol.
24. The process of claim 13 in which the stable, low-viscosity polymer polyol is characterized by a hydroxyl number of at least 50.
25. The process of claim 13 wherein the process comprises a semi-batch process.
26. The process of claim 13 wherein the process comprises a continuous process.
27. The stable, low-viscosity polymer polyol of claim 1 , wherein (D) said free-radical polymerization initiator is selected from the group consisting of persulfates, perborates, percarbonates and mixtures thereof.