Preparation of double metal cyanide-catalyzed polyols by continuous addition of starter
AssigneeArco Chemical Technology, L.P.
InventorJose F. Pazos
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Abstract
Double metal cyanide-catalyzed polyols are made by an improved process in which a starter is continuously added during polymerization of the epoxide. The process includes a continuously added starter (S.sub.c), and optionally, an initially charged starter (S.sub.i). The continuously added starter comprises at least about 2 equivalent percent of the total starter used. The process enables the use of water and low molecular weight polyol starters in DMC-catalyzed polyol synthesis. In addition, the process gives polyether polyols having reduced levels of high molecular weight polyol tail, which can adversely affect polyurethane foam processing.
Claims19
A process which comprises making a polyether polyol by polymerizing an epoxide in the presence of:
- (a) a double metal cyanide (DMC) catalyst;
- (b) a continuously added starter (S.sub.c);
- and
- (c) optionally, an initially charged starter (S.sub.i);
- wherein the S.sub.c comprises at least about 2 eq. % of the total starter used;
- and
- wherein the epoxide and the S.sub.c are continuously added to the reactor during the polymerization.
A process which comprises making a polyether polyol by polymerizing an epoxide in the presence of:
- (a) a zinc hexacyanocobaltate/tert-butyl alcohol complex catalyst;
- (b) a continuously added starter (S.sub.c);
- and
- (c) optionally, an initially charged starter (S.sub.i);
- wherein the S.sub.c comprises at least about 2 eq. % of the total starter used;
- wherein the epoxide and the S.sub.c are continuously added to the reactor during the polymerization;
- and
- wherein the resulting polyether polyol contains a reduced amount of high molecular weight polyol tail compared with a polyether polyol made without continuous addition of starter.
A polyether polyol made by DMC catalysis which comprises an amount of high molecular weight tail less than about y ppm, where y=P.sub.z x.sup.2 in which x is the number average molecular weight of the polyether polyol divided by 1000, and P.sub.z has a value within the range of about 30 to about 40, wherein the tail has a number average molecular weight greater than about 100,000 as measured by gel permeation chromatography using an evaporative light scattering detector and polystyrene standards.
Dependencies are inferred from the claim text.