Continuous Process for Making Polyether Polyols

Abstract

An alkylene oxide mixture containing greater than 50% by weight ethylene oxide is continuously polymerized in the presence of a double metal cyanide polymerization catalyst and an alkoxylated initiator having a hydroxyl equivalent weight of up to 200. The catalyst remains active, producing a polyol having an equivalent weight of up to 700 with a high oxyethylene content continuously at fast reaction rates.

Claims

1. A continuous process for producing a polyether product having a hydroxyl equivalent weight of 200 to 2000, comprising: a) forming in a continuous reactor a mixture of a double metal cyanide catalyst, an alkylene oxide mixture containing propylene oxide and at least 60% by weight ethylene oxide based on the weight of the alkylene oxide, at least one alkoxylated initiator compound having at least one hydroxyl group, a hydroxyl equivalent weight of 70 to 200 but lower than that of the polyether product, and a polymerizate consisting of alkoxylated species having molecular weights greater than the initiator compound and up to and including molecular weight of the polyether product, and b) continuously adding additional catalyst, additional alkylene oxide mixture containing propylene oxide and at least 60% by weight ethylene oxide based on the weight of the alkylene oxide, and additional initiator compound to the continuous reactor under polymerization conditions and continuously withdrawing a product stream containing the polyether product from the continuous reactor, wherein: i) steps a) and b) are performed in the substantial absence of a magnesium, Group 3-Group 15 metal or lanthanide series metal bonded to at least one alkoxide, aryloxy, carboxylate, acyl, pyrophosphate, phosphate, thiophosphate, dithiophosphate, phosphate ester, thiophosphate ester, amide, siloxide, hydride, oxide, carbamate or hydrocarbon anion and which is devoid of halide anions, and ii) the polyether product contains 50 to 90% by weight polymerized ethylene oxide.

2. The continuous process of claim 1, wherein prior to step b), steady-state concentrations of the double metal cyanide catalyst, the alkylene oxide mixture and the initiator compound are established in the continuous reactor under polymerization conditions, and such steady-state concentrations are maintained during step b).

3. The method of claim 2, wherein the initiator compound has a hydroxyl equivalent weight of 70 to 150.

4. The method of claim 3 wherein the initiator compound is a 70 to 150 equivalent weight alkoxylate of one or more of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, glycerin, trimethylolpropane, pentaerythritol, sucrose and sorbitol.

5. (canceled)

6. The method of claim 4 wherein the initiator compound is a 70 to 125 equivalent weight propoxylate of glycerin or trimethylolpropane.

7. The method of claim 3, wherein the polyether product has a hydroxyl equivalent weight of 200 to 1750.

8. The method of claim 3, wherein the polyether product has a hydroxyl equivalent weight of 200 to 700.

9. The method of claim 3, wherein the polyether product has a hydroxyl equivalent weight of 275 to 400.

10. The method of claim 3, wherein the alkylene oxide mixtures in steps a) and b) contain 65 to 90% by weight ethylene oxide and correspondingly 35 to 10% by weight propylene oxide.

11. The method of claim 10, wherein the alkylene oxide mixtures in steps a) and b) contain 70 to 85% by weight ethylene oxide and correspondingly 30 to 15% by weight propylene oxide.

12. The method of claim 11, wherein the alkylene oxide mixtures in steps a) and b) contain 75 to 85% by weight ethylene oxide and correspondingly 25 to 15% by weight propylene oxide.

13. The method of claim 3, wherein the double metal cyanide catalyst is a zinc hexacyanocobaltate catalyst complex.

14. The method of any preceding claim, wherein the amount of double metal cyanide catalyst is present in step b) at a concentration of 25 to 100 ppm by weight.

Description

EXAMPLE 1

[0041] Polyol A is a 168 hydroxyl number (333 equivalent weight, 1000 molecular weight), trifunctional random copolymer or propylene oxide and ethylene oxide. Polyol A contains 60% by weight oxyethylene units. 1 kg of Polyol A is charged into a 1 L Buchi reactor heated via an external jacket. The reactor is equipped with injection ports for introduction of reactants and a withdrawal port for removing a product stream. Pressure control is maintained via a pressure control valve on an exit line attached to the withdrawal port. A near infrared cell is set at the reactor outlet to measure unreacted oxide content in the product stream.

[0042] The reactor and Polyol A are heated to 160 C. At this temperature, (1) a catalyst slurry consisting of 0.1 wt-% a zinc hexacyanocobaltate catalyst complex in Polyol A is fed continuously to the reactor at a rate of 12 g/hour; (2) a propoxylated glycerin initiator having a molecular weight of 260 is fed continuously to the reactor at a rate of 75 g/hour and (3) a mixture of 80.5 wt-% ethylene oxide and 19.5 wt-% propylene oxide is fed continuously to the reactor at a rate of 223 g/hr. Once the reactor reaches its fill point, 310 g/hour of a product stream is withdrawn from the reactor. These feed and withdrawal rates produce a concentration of 40 ppm of DMC catalyst in the reactor and in the withdrawn product stream.

[0043] After operating at these conditions for 15 hours, product is collected during another 24 hours of operation until the experiment is arbitrarily discontinued. The level of unreacted oxides in the product stream remains at 1% during the entire reaction period, indicating that the DMC catalyst remains active throughout. The product has a hydroxyl number of 167 (336 equivalent weight, 1008 molecular weight) and contains 60% by weight oxyethylene units.

EXAMPLE 2

[0044] Example 1 is repeated, altering the flow rates as follows: (1) catalyst mixture in Polyol A15.9 g/hr; propoxylated glycerin initiator having a molecular weight of 260 g/mol38 g/hr; ethylene oxide/propylene oxide mixture114 g/hr; product stream167.9 g/hr. These flow rates produce a concentration of 95 ppm of the DMC catalyst in the reactor and in the product stream. These conditions are maintained for 15 hours, and for another 24 hours during which product is collected, after which the experiment is arbitrarily discontinued. Unreacted oxide content in the product stream is below 1% by weight during the entire run, again indicating no loss of DMC activity. The product has a hydroxyl number of 168 (333 equivalent weight, 1000 molecular weight) and contains 60% by weight oxyethylene units.

[0045] The product from Example 2 is used in a viscoelastic foam formulation as described in Table 1 following. The foam is made by mixing all components and immediately dispensing the resulting mixture into a box and allowing the foam to rise against atmospheric pressure. For comparison, an otherwise like foam formulation is made, replacing the product from Example 2 with Polyol A.

TABLE-US-00001 TABLE 1 Parts by Weight Ingredient Comp. A* Inventive Polyol A 60 0 Polyol of Example 2 0 60 1000 Molecular Weight triol 20 20 3100 Molecular Weight EO/PO 20 20 triol Water 2 2 Silicone surfactant 0.8 0.8 70% Bis(2- 0.2 0.2 dimethylaminoethyl)ether) solution 33% triethylenediamine solution 0.05 0.05 Stannous Octoate 0.05 0.05 Polymeric MDI 47.86 (75 index) 47.86 (75 index)

[0046] The blow-off time is determined by observing the rising foam, and is calculated from the time the foam mixture is poured into the box. Airflow, compression set (90% compression, parallel), foam density, indentation force deflection, resilience, tensile strength and tear strength are measured according to ASTM D 3574-01, and viscoelastic recovery (load at 25%, 65% and 75% deflection, support factor and recovery time) are measured according to the BASF Compression Recovery test. Results are as indicated in Table 2.

TABLE-US-00002 TABLE 2 Comp. A. Inventive Test Blow off time, s 101 146 Airflow, L/s (cubic feet/minute) 1.9 (4.1) 1.8 (3.8) VE Recovery Load @ 25% Deflection, N (lbf) 11.6 (2.6) 9.8 (2.2) Load @ 65% Deflection (lbf) 19.6 (4.4) 20.9 (4.7) Load @ 75% Deflection (lbf) 30.2 (6.8) 36.5 (8.2) Support Factor (%) 1.7 2.1 CS 90%, % 0.7 0.7 Density, kg/m.sup.3 (pcf) 49.6 (3.1) 52.8 (3.3) Indentation Force Deflection Load @ 25%, N (lbf) 56.0 (12.6) 68.1 (15.3) Load @ 65%, N (lbf) 110.7 (24.9) 139.7 (31.4) Load @ 25%, N (lbf) 52.0 (11.7) 62.7 (14.1) Support Factor, % 2.0 2.1 Hysteresis, % 92.9 91.9 Resiliency, % 4 4 Tear strength, N/m (lbf/in) 175 (1.0) 164 (0.94) Tensile strength, kPa (psi) 49.9 (7.1) 61.4 (8.9) Elongation at break, % 103 94