MACROMER AND PROCESS FOR MAKING POLYMER POLYOLS

Abstract

Polyether polyols are prepared by polymerizing unsaturated monomers in a continuous phase of a base polyol. A macromer or polymerization produce of such a macromer is present during the polymerization to stabilize the polymer particles as they form. The macromer is a polyether capped with certain unsaturated epoxide compounds.

Claims

1. A process for making a polymer polyol, comprising polymerizing one or more low molecular weight ethylenically unsaturated monomers that have a molecular weight of no greater than 150 in a continuous liquid polyol phase and in the presence of a stabilizer to form a dispersion of solid polymer particles in the continuous liquid polyol phase, wherein the stabilizer includes (i) a macromer produced in a reaction of a hydroxyl-containing polyether with an epoxide compound having a polymerizable carbon-carbon double bond; (ii) a pre-formed polymer formed by polymerizing a carbon-carbon double bond of such macromer, or (iii) a mixture of (i) and (ii) wherein the epoxide compound is represented by structure I: ##STR00004## where a is a positive number, R is a covalent bond or an organic linking group and R.sup.1 is hydrogen or hydrocarbyl group having up to 6 carbon atoms.

2. The process of claim 1, wherein at least 75% by weight of the stabilizer is the macromer.

3. The process of claim 2, wherein at least 95% by weight of the stabilizer is the macromer.

4. The process of claim 2, wherein the hydroxyl-containing polyether is a random copolymer of a mixture of 84 to 90% propylene oxide and 10 to 16% ethylene oxide, based on the weight of the polyether.

5. The process of claim 2, wherein the macromer has a molecular weight from 8000 to 15,000.

6. The process of claim 2, wherein the macromer contains an average of 4 to 6 hydroxyl groups per molecule and 1 to 1.5 polymerizable carbon-carbon double bonds per molecule.

7. The process of claim 2, wherein the epoxide compound has a molecular weight of up to 300.

8. The process of claim 2, wherein the epoxide compound is a vinyl aromatic compound or an isopropenyl aromatic compound.

9. The process of claim 2, wherein the epoxide compound is one or more of isopropenyl benzyl glycidyl ether; and vinyl benzyl glycidyl ether.

10. The process of claim 2, wherein the low molecular weight ethylenically unsaturated monomers include at least one of styrene and acrylonitrile.

11. The process of claim 10, wherein the low molecular weight ethylenically unsaturated monomers include styrene and acrylonitrile at a weight ratio of 85:15 to 50:50.

12. A polymer polyol made in accordance claim 1.

13. A polyurethane foam which is produced by reacting a polymer polyol of claim 12 with an organic polyisocyanate in the presence of a blowing agent.

14. A method of producing a capped polyether, comprising the steps of a) producing a polyether in the presence of an alkali metal hydroxide or an alkali metal alkoxide polymerization catalyst to produce a polyether having terminal —O.sup.−M.sup.+ moieties, which M represents an alkali metal, and b) combining the polyether having terminal —O.sup.−M.sup.+ moieties with an epoxide compound, and reacting the polyether and epoxide compound to produce a capped polyether, wherein the epoxide compound is represented by structure I: ##STR00005## where a is a positive number, R is a covalent bond or an organic linking group and R.sup.1 is hydrogen or hydrocarbyl group having up to 6 carbon atoms.

Description

EXAMPLES

[0067] Vinyl benzyl glycidyl ether (VBGE) is synthesized as follows: 4-vinylphenyl methanol (98.3 parts), epichlorohydrin (106.2 parts), triethyl amine (74.2 parts) and NaOH (29.3) parts are mixed in a flask in an ice bath and stirred overnight. The resulting product is filtered. The filtrate is stripped under vacuum to remove triethylamine and then at 80° C. and 10 millibars pressure until no further vapors condense. The product vinyl benzyl glycidyl ether is confirmed by NMR and gas chromatography.

[0068] 100 parts of a nominally hexafunctional, 1864 equivalent weight random copolymer of 88.5% propylene oxide and 11.5% ethylene oxide are combined with about 2000 ppm of potassium hydroxide. 0.7 parts of VBGE are added at room temperature and the resulting reaction mixture is held at that temperature under a nitrogen atmosphere for 24 hours. The product is filtered and t-butyl catechol is dissolved into it. These amounts of VBGE and copolymer correspond to a mole ratio of approximately 0.41 moles of VBGE per mole of copolymer. About 87% of the VBGE reacts under these conditions. The product is a mixture of macromer and unreacted copolymer, the macromer constituting approximately 36% of the total weight of product. The macromer molecules mostly have 6 hydroxyl groups and a single terminal carbon-carbon double bond.

[0069] When a similar capping reaction is performed substituting isopropenylphenyl glycidyl ether for the VBGE, only about 9% of the isopropenylphenyl glycidyl ethereacts to form macromer, and various unwanted side-products form. When divinylbenzene monoxide is substituted for the VBGE, only about 50% of the divinylbenzene monoxide reacts.

[0070] Polymer polyol Example 1 is prepared by charging a stirred reactor with a mixture of 58.1 parts of a base polyol (a 1000 hydroxyl equivalent weight, nominally trifunctional random copolymer of 88.5% propylene oxide and 11.5% ethylene oxide), 2.5 parts of a previous-formed polymer polyol (the heel of a previous polymerization reaction) and 5.0 parts of the mixture of macromer and unreacted copolymer from above (i.e., about 1.8 parts of the macromer). This mixture is purged with nitrogen and vacuum several times. The internal reactor pressure is brought to 10 kPa and the mixture is then heated to 125° C. Separately, 70 parts of styrene, 30 parts of acrylonitrile, 0.49 parts of n-dodecylmercaptan and 0.18 parts of a free radical initiator are homogenized in a small amount of the base polyol. This blend is added to the stirred reactor at a uniform rate over three hours. At the end of the monomer addition, a blend of a second free radical initiator in a small amount of base polyol is added. The reaction temperature is then increased by 5° C. every 30 minutes until a temperature of 145° C. is attained, after which the reactor contents are allowed to react for another 60 minutes. The reactor is then cooled to 40° C. The resulting product is stripped under vacuum. This product, a stable, uniform dispersion of polymer particles in the base polyol, is designated Example 1. It contains 34% by weight dispersed styrene-acrylonitrile particles. The product is stable against settling and otherwise is similar in properties to an otherwise like polymer polyol product made using a TMI-capped polyether as the macromer.

[0071] Comparative Polymer Polyol A is made in the same general manner, increasing the amounts of styrene and acrylonitrile to produce a 43% solids copolymer polyol product. The stabilizer in this case is made by capping 100 parts by weight of the 1864 equivalent weight copolymer with 0.9 parts of TMI (3-isopropenyl-α,α-dimethylbenzylisocyanate). This results in a mixture containing about 45% capped copolymer and 55% of the 1864 equivalent weight copolymer.

[0072] Comparative Polymer Polyol B is made using the same ingredients as Comparative Polymer Polyol A, except in a continuous process. The polymer polyol has made has 44% solids.

[0073] The particles of Polymer Polyol Example 1 are similarly sized to those of Comparative Samples A and B, with essentially all particles having a size of less than 10 μm as measured by laser diffraction methods.

[0074] Flexible polyurethane foams are made from each of Polymer Polyol Example 1 and Comparative Polymer Polyols A and B. The formulations are as set forth in Table 1. The various ingredients are separately weighed out into suitably sized vessels. Polyol A (a 3500 molecular weight, nominally trifunctional random copolymer of propylene oxide and ethylene oxide), the polymer polyol, silicone surfactant, water and amine catalysts are combined in a flask using a high speed mixer at 23±3° C. A greater amount of Polyol A is added in Comparative Samples F-A through F-D to dilute the formulations to equivalent levels of styrene-acrylonitrile particles. Stannous octoate is added after 30 seconds, followed 10 seconds later by the polyisocyanate. The reaction mixture is mixed for an additional 10 seconds and then poured into an open 8 liter box, where it rises. 320 seconds after the polyisocyanate (80/20 mixture of 2,4- and 2,6-toluene diisocyanate) is added, the foams are transferred to a 140° C. oven for 5 minutes to complete the cure. The foams are then aged for 24 hours at 23±3° C. for 24 hours before samples are taken for property testing.

[0075] The foams are evaluated for density (ISO 845), compression force deflection (CFD) (ISO 3386-1), tensile and elongation (ISO1798), tear strength (ISO 8067) resilience (ASTM D3574), airflow (ISO7231), compression set (ISO 1856) and wet compression set (ISO 13362). Results are as indicated in Table 2.

TABLE-US-00001 TABLE 1 Parts by Weight Ingredient Ex. 1 F-A* F-B* Ex. 2 F-C* F-D* Polyol A 70.4 76.7 77.3 70.4 76.7 77.3 Polymer Polyol 29.6 0 0 29.6 0 0 Ex. 1 Polymer Polyol A 0 23.3 0 0 23.3 0 Polymer Polyol B 0 0 22.7 0 0 22.7 Amine Catalysts.sup.1 0.16 0.16 0.16 0.10 0.10 0.10 Silicone 0.8 0.8 0.8 0.5 0.5 0.5 Surfactant.sup.2 Stannous Octoate 0.18 0.18 0.18 0.15 0.15 0.15 Water 3.9 3.9 3.9 2.2 2.2. 2.2 TDI (index) 110 110 110 110 110 110 *Not an example of the invention. .sup.1A mixture of bis(dimethylaminoethyl)ether and triethylendiamine. .sup.2Niax L580, from Momentive Per omance Materials.

TABLE-US-00002 TABLE 2 Result Property Ex. 1 F-A* F-B* Ex. 2 F-C* F-D* Density, kg/m.sup.3 27.5 27.25 26.9 41.7 41.6 41.5 CFD (40%), kPa 5.2 5.2 5.8 5.5 5.5 5.8 CFD Sag factor 2.6 2.5 2.5 2.5 2.5 2.5 CFD Hysteresis, % 57.8 56.8 56.7 73.7 73.8 73.5 Tensile Str., kPa 133 129 131 147 135 141 Elongation, % 147 148 130 151 147 136 Tear Str., N/m 385 425 357 371 378 486 Resilience, % 35.8 31.3 30.3 42.0 41.3 41.0 75% Compression 12 19 11 5 6 5 Set, % 90% Compression 23 18 17 11 12 11 Set, % Wet Compression 14 16 10 4 4 4 Set, % *Not an example of the invention.

[0076] As the foregoing data shows, the macromer made using VBGE produces a polyurethane foam having properties that are not meaningfully different from those produced using a TMI-capped macromer.