A PROCESS FOR PRODUCING POLYMER-POLYOLS USEFUL IN THE PREPARATION OF POLYURETHANES

Abstract: Adducts, improved polymer-polyols and improved poly­ urethane foams are provided. The adducts are produced by reacting suitable polyol and epoxy co-reactant to essen­ tially eliminate all epoxy groups. The polymer-polyol is produced by polymerizing suitable ethylenically un­ saturated monomer in the adduct or in the adduct forming mixture, in the later case the adduct forming reaction and the polymerization reaction occur simultaneously to produce the polymer-polyol. Polyurethane foams are produced by the usual method but employing the novel adduct or polymer-polyol of the present invention.

Description: FIELD OF INVENTION The present invention relates to improvement of the physical properties of polyurethanes. Improved polyols and improved polymer-polyols having char acteristics tailored to the production Qf improved polyurethanes are provided. More specifically, the present invention relates to novel epoxy-modified polyols, which are useful reactants for producing a wide variety of synthetic plastic and elastic products. These epoxy-modified polyols may be used,for example, to produce cellular products, films, coatings, and cast or molded articles, such as, but not limited to, polyurethanes. Where cellular or microporous articles are produced, significant improvements may be obtained in the stability of the foam-forming dispersion as well as in the load bearing characteristics, tensile strength, and stability of cell structure of the foams. More importantly, the epoxy-modified polyols can be used to produce epoxy-modified polymer-polyols (EMPP). In one particularly useful aspect of the invention, the EMPP are employed in the production of polyurethanes, especially cellular poly rethanes. Cellular polyurethane foams constitute a broad class of polymeric materials having physical characteristics ranging from rigid to elastic-rubbery surface. The polymers are produced through the interaction of a polyfunctional isocyanate with a polyfunctional chemical compound having an active hydrogen : its structure such as a polyester, polyesteramide, polyether or a mixture of two or more such materials. The active-hydrogen-containing material is generally a liquid, or a solid capable of being melted at a relatively low temperature. The materials donventionally used contain hydroxyl groups as the radicals having the active hydrogen and are generally termed "polyols". Despite the variety of physical and chemical properties obtainable by proper selection of the polyisocyanate and the polyol as well as by controlling the conditions under which the reaction is carried out, there are definite limitations in selecting components for optimization of desirable properties in the resulting product. One of the mostsignificant of such limitations arises from the fact that the polyol must be sufficiently liquid at the appropriate reaction temperature to permit mixing and reaction with the polyfunctional isocyanate in producing a polyurethane resin. This re quirement generally results in the use of polyols of relatively low molecular weight. However, the utility of polyols of low molecular weight is generally limited to producing rigid products. The use of higher molecular weight components is attended by a variety of other difficulties including handling and compounding problems. For example, polyol viscosity may be excessively high. One known technique for producing polyurethanes with better properties incorporating higher-molecular weight components while minimizing the disadvantages mentioned above, involves employing polymer-polyols in place of or in conjunction with simple polyols for reaction with polyisocyanates to produce polyurethanes. However, the stability of polymer-polyols generally decreases with decreasing molecular weight of the polyols used to make them, and it is difficult to avoid using relatively low molecular-weight polyols for the reasons discussed above. Instability of polymer-polyols may lead to breakdown of the polymer-polyol: dispersion during preparation and storage, resulting in coagu- lation. As is known in the art, it is not possible to make acceptable products with coagulated polymer-polyols, because mixing and homogeneous reaction of the reactants cannot practicably be achieved. Also, among the polymer-polyols of greatest commercial significance have been those formed as reaction products of styrene, acrylonitrile and a polyol. There are several potential disadvantages to such systems. It is known that polymers containing acrylonitrile as a major component tend to become discolored during cure, probably because of the exothermic nature of the reaction during polyurethane formation. It is also known that styrene, when substituted for a major portion of the acrylonitrile, will prevent discoloration. However, it is normally difficult to employ high styrene-acrylonitrile ratios because the stability of reaction mixtures containing polymer-polyols generally decreases with increasing styrene content. The instability similarly can lead to difficulties in making the polymer-polyol dispersion or in breakdown after the polymer-polyol dispersion is made, resulting in coagulation. As a consequence of the above difficulties, commercial operations have often been constrained to using relatively high acrylonitrile-styrene ratios and making products in which foam discoloration was not an important consideration. It would be desirable to provide improved techniques for producing polyurethane foams incorporating higher molecular weight components, while avoiding problems such as foam discoloration and coagulation of the polymer-polyol dispersions. Incorporation of higher molecular weight components in the reaction mixtures would lead to higher indentation load bearing capacity (hereinafter "ILD"),tensile strength (hereinafter "TES"), and flexibility of the final products, the benefits of such improved properties being well known in the art. Improvements in these important foam properties in turn would permit reduction of the foam density needed to achieve a given level of foam strength (e.g., ILD and TES), permitting reduction in the amount of polymer needed to produce a slab of foam having a given size, as well as reducing the unit volume weight of the product. In view of the widespread use of polyurethane foam materials in automobiles, and the current pressure to reduce the weight of automobile components wherever possible; production of polyurethane foams having a given ILD and TES at reduced weight is an important continuing goal in the polyurethane industry. The products discussed above should be useful in other fields as well, such as in the production of slab stock for use by the furniture industry in seat cushions, mattresses and a variety of other products. The epoxy-modified polymer-polyols of the present invention may be advantageously employed to improve other types of products besides polyurethane foams, including but not limited to solid polyurethane products, and polyester products. Articles with improved physical properties (e.g., ILD and TES) may be produced by the practice of the invention with those epoxy-modified polymer-polyols which appear to act as protective colloids, preventing agglomeration of polymer particles and thus averting coagulation. Improvements in the ultimate products can be expected, since improvements in the stablity of polymer-polyols will produce more uniform products, with better physical properties. DESCRIpTIDN OF THE PRIOR ART The basic polymer-polyol technology is disclosed in U.S. Reissue 28,715 and U.S. Reissue 29,118. U.S. Reissue 29,118 discloses polymer-polyols comprising (1) a relatively high-molecular weight film-forming polymer having radicals which are reactive with the -N=C=O radicals of the isocyanate used to form the polyurethane, and (2) a reactive solvent (such as polyol) which is a solvent or dispersing medium for the polymer, and which also contains radicals which are reactive with the isocyanato group. Polyols according to the invention must have an average molecular weight of at least 500 grams per mole, preferably at least 1,000 grams per mole, in order to produce polymer-polyols of acceptable quality. U.S. Patent 3,953,393 discloses the production of polymer-polyols which may be used to produce polyurethanes, such as polyurethane foams, by the in situ polymerization of a vinyl monomer in an unsaturated polyol in the presence of a free radical catalyst. The unsaturated polyol may be prepared by reaction of any conventional polyol with an organic compound having both ethylenic unsaturation and a hydroxyl, carboxyl or epoxy group. The organic compounds which can be used include unsaturated polycarboxylic acids and anhydrides and unsaturated epoxides. In all instances, the key is to introduce substantial unsaturation into the polyols or polymer-polyols and only epoxides having unsaturation are used'for that purpose. This is to be compared to the present invention in which unsaturation in the polymerpolyol is insignificant and accidental, and essentially, unsaturation is avoided. Other patents of similar relevance include U.S. 3,652,639 U.S. 3,950,317 , U.S. 3,823,201 , U.S. Reissue 29,014 -- U.S. 3,931,450 U.S. 4,014,846 , and U.S. 4,093,573 Patents which disclose producing adducts of a polyol and a polycarboxylic acid, which then are reacted with an epoxide to yield an adduct in which substantially all'free carboxyl groups are neutralized, include Japanese Kokai 48/101494/73, Japanese Kokai 48/101498/73, British Patent 1,126,025, and British Patent 1,217,005. U.S. Patent 2,996,551 , discloses adducts produced by first reacting a polyol with a monoepoxide such as propylene oxide to produce an intermediate, and then reacting the intermediate with a polyepoxide. While the patent notes that the products can be used as actsve-OH reactants, neither polyurethanes or polyurethane foams are mentioned. The invention described in the parent application serial No. 279,318, provides improved polymer-polyols comprising, inter alia, a mixture of: (A) a minor percentage by weight of an adduct formed by reaction of a first polyol with an epoxy co-reactant selected from the group consisting of diepoxides, polyepoxides having more than two epoxy groups and mixtures, in which at least one of the epoxy groups in the epoxy co-reactant remains unreacted after reaction with the polyol; or with a half-ester co-reactant formed by 1:1 molar reaction between (a) at least one polycarboxylic compound selected from the group consisting of dicarboxylic acids, dicarboxylic acid anhydrides, polycarboxylic acids having at least three carboxylic carbon atoms and polycarboxylic anhydrides having at least three carboxylic carbon atoms, and (b) at least one epoxy compound selected from thegroup consisting of diepoxides and polyepoxides having at least three epoxy groups, in which at least one of the epoxy groups of the epoxy compound remains unreacted after the 1:1 molar reaction; (B) a second polyol; and (C) at least one ethylenically unsaturated monomer which is reactive with free hydroxyl groups of the first and second polyols, in which (C) has been polymerized in (A) and (B) by free radical addition polymerization to a substantially linear polymer having a molecular weight of at least about 5,000 to provide a liquid stable dispersion of polymer-polyol. In an additional embodiment, that prior Invention provides improved polyurethane products including polyurethane foams, produced using the improved polymer-po lyols. GENERAL DESCRIPTION OF THE INVENTION It has been found, according to the present invention, that improved high molecular weight elastic, plastic, cellular and microcellular products including polyurethane products, and in particular polyurethane foams, may be produced by employing and incorporating as an agent for co-reaction with a polyisocyanate, the specially-produced epoxy-modified polyol of the invention. Unlike the invention of my parent application, all but traces of the epoxy groups of the modifiers are reacted in the modified polyol. These modified polyols can be used to replace prior art polyols or, preferably, may be converted to modified polymer-polyols which are useful in place of prior polyols and polymer-polyols. The modified polyols and polymer-polyols of the invention, which will be discussed in detail below, may be combined in undiluted form directly with a polyisocyanate (and optionally another polyol) to produce a polyurethane. In other embodiments, the modified polyols and polymer-polyols of the invention may be used in producing polymer products other than polyurethanes. By the practices of the present invention, it is possible to employ polyols of lower molecular weight without the instability problems and coagulation problems associated with such polyols. It is also possible to use the product in the production of polymer-polyols, such as the styrene-acrylonitrile-polyol combination, without the discoloration problems, thereby permitting a much greater degree of freedom in the design and development of polyurethane foams. Still another advantage of the improved polymer-polyol of the present invention is found in the obtaining of high and improved physical properties without significant viscosity and molecular changes, such that the polyurethane polymer which are obtained are less expensive than those obtained using high molecular weight polyols while avoiding the processing difficulties associated with the high molecular weight polyols. The present invention and its objects will become more apparent upon reference to the following detailed description and the appended claims. DETAILED DESCRIPTION OF THE INVENTION According to the present invention, epoxy-modified polyols and epoxy-modified polymer-polyols (the latter being referred to hereinafter as "EMPP") are produced which are effective in producing polyurethane products and particularly polyurethane foams. In one embodiment of the invention, the epoxy-modified polyol can be produced in the first step of a two-step process comprising (A) reacting at least one polyol with 2Z to o 10X by weight of at least one epoxide, including monoepoxides and polyepoxides, until no more than about a trace of the epoxy groups remain unreacted, and (B) polymerizing ethylenically unsaturated monomers in situ in the epoxy-modified polyol of step (A) to produce the EMPP. These EMPP's can then be utilized to produce polyurethanes in which the EMPP function as the polyol in the polyol-isocyanate reaction. A wide range of polyols can be used. Among the polyols which can be employed are one or more polyols from the following classes of compositions. (Minor amounts of polyhydroxyalkanes can be present). (a) Hydroxyl-terminated polyesters; (b) Alkylene oxides of polyhydroxyalkanes; (c) Trialkanolamines and alkylene oxide adducts thereof; (d) Alcohols derived from mono- and polyamines by addition of alkylene oxides; (e) Non-reducing sugars and sugar dersNàtives and alkylene oxide adducts thereof; (f) Alkylene oxide adducts of aromatic amine/phenol/aldehyde condensation products; Alkylene oxide adducts of phosphorus and polyphosphorus acids; (h) Polyphenols and alkylene oxide sdducts thereof; ; (i) Polytetramethylene glycols Particularly preferred polyols include poly(oxypropylene)glycols, triols and higher functionality polyols, poly(oxybutylene)glycols, triols and higher functionality polyols, and poly(oxypropylene-oxyethylene)polyols, similarly including glycols, triols and higher-functionality polyols. In the latter class of polyols, the oxyethylene content of the polyol is preferably less than 80%, most preferably less than 60tri of the total. When used, ethylene oxide can be included in any fashion along the polyol molecule chains, i.e., as internal blocks, terminal blocks, and/or in random patterns. Limited unsaturation in the polyol used does not adversely affect the operation of the invention, uniess the polyol has so much unsaturation that it is in the form of a highly crosslinked polymer or gel. The polyols employed can have hydroxyl numbers which vary over a wide range. In general, the hydroxyl numbers of the polyols employed can range from 20, and lower, to 400, and higher, preferably from 30 to 300, and most preferably, from 35 to 200. The hydroxyl number is defined as the number of milligrams of potassium hydroxide required for the complete hydrolysis of the fully acetylated derivative prepared from 1 gram of polyoL The hydroxyl number can also be computed by the equation: 56.1 @ 1000 @ F OH = M.W. where OH = hydroxyl number of the polyol P = functionality (average number of hydroxyl groups per molecule of polyol) M.W. = molecular weight of the polyoL- The exact polyol employed depends upon the end use of the polyurethane product to be produced. For example, in the case of foamed reaction products, the hydroxyl number is selected properly to result in flexible, semiflexible, or rigid foams. The above polyols preferably possess a hydroxyl number of from 200 to 400 when employed in rigid foam formulations, from 70 to 150 for seminexible foams, and from 20 to 70 when employed in flexible foam formulations. Such limits are not intended to be restrictive, but are merely illustrative of preferred polyols for particular applications. The average molecular weight of the polyols used can range from 500 grams per mole up to 9,000 grams per mole or more; preferably the average molecular weight ranges frown 1,000-4,000 grams per mole. Polyol average molecular weight has great influence on the character of the end products. The flexibility of polyurethane foams increases as the polyol tnolcculnr weight incrcases. As the polyol molecular weight decreases, more polyisocyanate is needed to produce an acceptable foam. Epoxy compounds which may be used include, as representative examples, 3,4-epoxycyclohexylmethyl-3,4-epoxy-cyclohpxane carboxylate, 1,4-butanediol diglycidyl ether, bis(3 ,,4-epoxycyclohexyl)adipate, and 2-(314-epoxycyclohexyl-5, 5-spiro -3,4-epoxy) cyclohexane-meta-dioxane. Suitable epoxy compounds are commercially available, for example, from the Union Carbide Corporation (New York) under the trade name BAKELITE, from the Ciba-Geigi Corporation (New York) under the trade name ARALDITE, Dow Chemical Company (Michigan), and Celenase Corporation (New York). Additional sources of suitable epoxy opmpòunds include the Viking Chemical Company (Minneapolis). The reaction between the polyol and the epoxide is preferably carried out at a temperature of 5O0-l000C, for 30 minutes to 3 hours. It is complete when most of the epoxy groups of the epoxide have reacted with the polyol, as determined by either the pyridinium chloride test or the potassium iodide test to be further explained below. The epoxy-modified polyol can also be produced as the adduct of a polyol and a half-ester intermediate formed as the reaction product of (1) at least one polycarboxylic compound selected from the group consisting of dicarboxylic acids, dicarboxylic acid anhydrides, polycarboxylic acids having at least three carboxylic carbon atoms and polycarboxylic anhydrides having at least three carboxylic carbon atoms, and (2) at least one epoxy compound. The epoxy compounds mentioned above are suitable for use to produce the adducts; the polycarboxylic and epoxy compounds' are allowed to react at a temperature of 100-140 C, preferably aboutl30 c for about a half-hour. The intermediate is then allowed to react with the polyol as described in the previous embodiment to produce the epoxymodified polyol. The times and temperatures specified above for the various reactions are exemplary but not required. Catalysts may be added to accelerate the reactions, as taught below in the Examples, permitting use of lower temperatures and shorter reaction times. Suitable btaLyts are well known in the art. Polymer-polyols are well known in the art. The basic technology is disclosed in U.S. Reissue 28,715 and U.S. Reissue 29,118. Generally, in order to produce a conventional polymer-polyol, an ethylenically unsaturated monomer is polymerized in situ in an appropriate polyol. The polymerization produces a stable, dispersed polymer in the polyol. The polymer dispersion, known as a polymer-polyol, can be employed as a reactant in a number of reactions (e.g., polyurethane-forming reactions) to introduce into the resultant product, as an integral part thereof, both the polyol and the dispersed polymer. The epoxy-modified polyols may be used in the same manner as polyols were previously used in forming polymer-polyols. Preferably, the unsaturated monomer is metered into the polyol reaction medium at a rate corresponding approximately to the polymerization reaction rate so that there is not a large amount of unreacted monomer in the reaction mixture at any particular time. An alternative method to all of the foregoing is to: (a) dissolve the epoxy compound in the unsaturated monomer, (b) react this mixture with a suitable polyol, and (c) polymerize the monomer in this mixture without separate formation and isolation of the epoxy-modified polyol. The resulting EMPP has excellent properties which makes this simplified process quite desirable. The conventional method for making polymer-polyols comprises the following steps which are known in the art: (a) Dispersing a minor amount of an ethylenically unsaturated monomer in a major amount of at least one normally liquid polyol having a molecular weight of at least about 500 and a hydroxyl number in the range of 20 to 600 by feeding the monomer into the polyol at a regular and continuous rate, and sO Polymerizing said monomer in said polyol by free radical addition polymerization in the presence of a conventional freeradical catalyst to a substantially linear polymer having a molecular weight of at least about 5,000 to provide a Liquid stable disnersion of Dolvmer-nolvol having n viscositv of less than about 40,000 EMI14.1 <tb> <SEP> r <SEP> s <SEP> r <SEP> <tb> (case <SEP> Xcentipoisc) <tb> at 10% polymer concentration. During this polymerization, a minor amount of graft or block polymer is inherently produced. Thus, regardless of whether or not the ethyBenicaliyz unsaturated monomer itself contains radicals reactive with the isocyanato group, the reactive compositions produced always contain film-forming polymer having radicals reactive with the Isocyanato group. Among ethylenically unsaturated monomers which do not have a radical reactive with the isocynnato group are styrene, methyl methacrylate and vinyl acetate; however, all of these produce, after polymerization, reactive compositions that contain a film-forming polymer haying a minor amount of reactive radicals introduced from the polymerization medium and the reactive compositions react with the isocyanato group. Polymer-polyols may be produced by polymerizing the ethylenically unsaturated monomers in the selected polyol at a temperature of from 400C to 1500C in the presence of a catalytically effective amount of a conventional free radical catalyst known to be suitable for the polymerization of ethylenically unsaturated monomers. Preferably, the monomers are fed into the polyol over about 3 -hours while maintaining the polyol at - 130-1400C, and the reactants are then maintained at 140-1500C for an additional hour. These are preferred but optional reaction conditions. A polyol chosen for use in producing a polymer-polyol must meet several requirements in addition to the requirements discussed above in relation to polyols in general: (1) It must act as a solvent or dispersing medium for the film- forming polymer produced by polymerization ot the ethylenicalltunsaturated monomers. (2) It must not be so reactive with the film-forming polymer as to reduce substantially the reactive radical content of either the solvent or the polymer or to form a gel or a hard infusible resin which would interfere with or even prevent the reaction with the polyisocyanate. (3) It should form stable solutions or diSpersions with the film forming polymer which are preferable dilutable without the formation of undesirable precipitates with the components used to form the polyurethane polymer. (4) It must be a liquid, at least at the temperature used for the reaction with the polyisocyanate (5) It must have at least two radicals which are reactive tvith the -N=C=O of the polyisocyanates so as to form a reaction product with the polyisocyanate. Among the polyols that can be employed for producing polymerpolyols are hydroxyl-terminated polyesters, polyhydroxyalkanes, Polyphenols, polyoxyalkylene polyols, and the corresponding mercapto derivatives. The monomers which may be used are the polymerizable monomers characterized in that they have at least one polymerizable ethylenically unsaturated group of the type, (C=C). The monomers can be used singly or in combination to produce homopolymer/polyol or copolymer/polyol reactive compositions. These monomers are well known in the art and include the hydrocarbon monomers such as butadiene, isoprene, 1,4-pentadiene, 1,6hexadiene, 1,7-octadiene, styrene, aipha-methylstyrene, methylstyrene, 2,4 dimcthylstyrene, ethylstyrene, isopropyistyrene, butylstyrene, phenylstyrene, cyclohcxyistyrcnc, bcnzylstyrcne; ; - substituted styrenes such as chlorostyrene, 2,5-dichlorostyrene, bromostyrene, nuorostyrene, trifluorom ethylstyrene, iodostyrene, cyanostyrene, nitrostyrene, N,N-dimethylaminostyrene, acetoxystyrene, methyl-4 vinylbenzoate, phenoxystyrene, pvinyl diphenyl sulfide, pvinylphenyl phenyl oxide; the acrylic and substituted acrylic monomers such as acrylic acid, methacrylic acid, methylacrylate, hydroxypropyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, methyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, Isopropyl methacrylate, hydroxypropyl methacrylate, octyl methacrylate, methacrylonitrile, methyl alpha-chloroacrylate, ethyl alpha-ethoxyacrylate, methyl alpha-acetaminoacrylate, butyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, phenyl methacrylate, ''acry-lonitrile, alphachloroacrylonitrile, substituted acrylamides including N,N amethylacrylamide, N,N-dibenzylacrylami de, and N-butylacrylamide acrylamide, methacrylyl formamide; the vinyl esters, vinyl ethers, vinyl ketones, such as vinyl acetate, vinyl chloroacetate, vinyl alcohol, vinyl butyrate, isopropenyl acetate, vinyl formate, vinyl acrylate, vinyl methacrylate, vinyl methoxy acetate, vinyl benzoate, vinyl iodide, vinyl toluene, vinyl naphthalene, vinyl bromide, vinyl fluoride, vinylidene bromide, l-chlorel-±1uoroethylene, vinylidene fluoride, vinyl methyl ether, vinyl ethyl ether, vinyl propyl ethers, vinyl butyl ethers1 vinyl 2-ethylhexyl ether, vinyl phenyl ether, vinyl 2-methoxyethyl ether, methoxybutadiene, vinyl 2-butoxyethyl ether, 3,4-dihydro-1,2-pyran, 2 butoxy-2lvinyloxy diethyl ether, vinyl 2-ethylmercaptoethyl ether, vinyl methyl ketone, vinyl ethyl ketone, vinyl phenyl ketone, vinyl ethyl sulfide, vinyl ethyl sulfone, N-methyl-N-vinyl acetamide, N-vinylpyrrolidone, vinyl imidazole, divinyl sulfide, divinyl sulfoxide, divinyl sulfone, sodium vinyl sulfonate, methyl vinyl sulfonate, N-vinyl pyrrole ; dimethyl fumarate, dimethyl maleate, maleic acid, crotonic acid, fumaric acid, itaconic acid, t-butylaminoethyl methacrylate, dimethylaminoethyl methacrylate, glycidyl acrylate, allyl alcohol, glycol monoesters of itaconic acid, diglycol esters of itaconic acid, methyl monoester of itaconic acid, dichlorobutadicne, vinyl pyridine, Any of the known polymerizable monomers can be used and the compounds listed above are illustrative and not restrictive of the monomers suitable for ec In this Invention. Any of the known chain transfer agents can be present it desired. Illustrative of catalysts which can be used In producing polymer- polyols are the well-known free radical types of vinyl polymerization catalysts, for example, the peroxides, persultates, perborates, percarbonates, azo compounds, including hydrogen peroxide, dibenzoyl peroxide, acetyl peroxide, benzoyl hydroperoxide, t-butyl hydroperoxide, t-butyl peroxybenzoate, alpha, alpha'-azo-2-m ethyl butyronitrile, alpha, alpha'-2-m ethyl heptonitril e, l,l'-azo-l-cyclohexane carbonitrile, dim ethyl alpha,alpha'-az-isobutyrate, 4,4'-azo-4- cyanopentanoic acid, azobisisobutyronitril e, persuceinie aeid, diisopropyl peroxy dicarbonate, a mixture of catalysts may also be used. The concentration of the catalyst can vary from 0.001 to 5 percent, preferably frdm s 0.2 to 0.5 percent; however, any effective catalytic amount is satisfactory. The polymerization can also be carried out with an inert organic solvent present. Illustrative thereof are toluene, benzene, acetonitrile, ethyl acetate, hexane, heptane, dicyclohexane, dioxane, acetone, N,N dimethylformamide, and N,N-dimethylacetamide. Acceptable polymer-polyols normally have a maximum polymer particle size ranging from 1 to 6 microns; preferably, from 1 to 3 microns; and most preferably, about 1 micron or less. Polymer-polyols having particles of maximum diameter of less than 1 micron are considered for the purposes of this invention to be on the borderline of invisibility when examined under a microscope. Polymer-polyols having particles of 1-3 microns maximum diameter are considered to be of medium size. Polymer-polyols having particles of 4-6 microns maximum diameter are considered to be of large size. Polymer-polyols should contain from 5 to 50% by weight of dispersed polymer. A preferable concentration is 20 to 50% by weight. Polymer-polyols having in excess of about 50% by weight of dispersed polymer are ordinarily too viscous for practical purposes. The EMPP can be used to produce polyurethane products, particularly polyurethane foams. Where EMPP is used as the polymer-polyol, upon addition d a polyisocyanate to the polymer-polyol, reaction occurs with the isocyanato groups,and'the EMPP is chemically and integrally bound in the resulting polyurethane. The epoxy-modified polymer-polyols may be used in prepolymer processes, quasi-prepolymer processes and one-shot processes as known to those skilled in the art. The polyurethanes say be further reacted with epoxy resins, cured with sulfur, peroxides or other curing agents, or otherwise reacted or modified as known to those skilled in the art. In using the one-shot process for production of polyurethanes, it is desirable to also use a silicone oil emulsifier as, described in U.S. 2,834,748 and 2,917,480 The isocyanates used to form the polyurethanes of the present invention must be polyfunctional. Examples of such polyisocyanates are the toluene diisocyanates, hexamethylene diisocyanates, diphenylmethane diisocyanates, naphthalene diisocyanates, triphenyim ethane triisocyanates, phenylene diisocyanates, dim ethyl diphenylm ethane diisocyanates, triisocyanatodiphenyl ethers, et cetera, such as meta-toluene diisocyanate, 4,4'-diphenyl diisocyanate, 4,4'-diphenylene methane diisocyanate, 1,5 naphthalene diisocyanate, 4,4'-diphenyl ether diisocyanate, pphenylene diisocyanate, ethylene diisocyanate, trim ethylene diisocyanate, cyclohexylene diisocyanate, 2-chloropropane diisocyanate, xylylene diisocyanates. . A mixture of 80% 2,4-tolylene diisocyanate and 20% 2,6-tolylene diisocyanate is particularly preferred; this mixture will be referred to hereinafter as toluene diisocyanate. Other polylsocyanates which can be used will occur to those skilled in the art. The extremely versatile nature of the invention makes possible the production of products having a vide variety of characteristics, and can effectively be used for forming not only cellular and' microceflular polyurethane products, but also films, coatings, cast or molded articles, As is well known cellular polyurethane products may be obtained by inducing the polyurethane reaction in the presence of a gas-producing agent or "blbwing agent" such as a fluorohydrocarbon. Alternatively, the polyurethane-producing reaction may be induced in the presence of water, which reacts with the isocyanate to release carbon dioxide, an effective blowing agent. An excess of the polyisocyanate should be used to compensate for the loss of polyisocyanate due to reaction with water. Since water acts indirectly to release carbon dioxide, water will be considered as a blowing agent in this invention. By this invention, in which polyurethanes and polyurethane foams are produced using the epoxy-modified polymer-polyols discussed above, significant improvements may be obtained in the load bearing characteristics (ILD) of foam products as well as the tensile strength (TES) and stability of the foam cells. In a preferred embodiment of the invention, styrene and acrylonitrile are copolymerized in an EM P of the invention and subsequently reacted with a polyisocyanate to produce a polyurethane. The polyurethane can be expanded conventionally to produce a foam. As discussed earlier, there have been difficulties in the past with using the styrene-acrylonitrile systems for producing polyurethanes. In particular, high styrene-acrylonitrile ratios lead to instability of the reaction mixtures used to produce polymer-polyols.Slab stock production using low styrene-acrylonitrile ratios or acrylonitrile alone results in excessive buildup of heat causing discoloration in the absence of high styrene components. This invention alleviates these problems, as it is possible to produce polyurethane reaction mixtures at a given solids concentration and polyol molecular weight, having high styrene-acrylonitrile ratios, without the attendant problems of dispersion instability and product discoloration. The styrene-acrylonitrile ratios according to the invention are preferably in the range from 50:50 up to 100:0; an approximately 60:40 to 80:20 ratio is preferred and a 70:30 ratio is particularly preferred. The polymer dispersions obtained according to this aspect of the invention are characterized by a minute particle size, i.e., little or no tendency to kE it coggulation or excessive grit content. This invention is further illustrated by the following examples, without, however, being restricted thereto. All parts are by weight, unless otherwise specified. Commercially available polyols useful in the Examples include: Polyol A - Polypropylene oxide - polyethylene oxide triol made from propylene and ethylene oxide and glycerine, and having a theoretical number average molecular weight of 6200 and a hydroxyl number of about 25. The alkylene oxide units are present primarily in blocks and the end units are substantially all ethylene oxide units, i.e. the ethylene oxide is used to "cap" the triol. Based on its total weight, this triol contains about 14 weight per cent ethylene oxide. (Such a polyol is commercially available from BASF Wyandotte Corporation under the trade name Pluracol 380 Polyol). Polyol B - Polyproplene oxide-polyethylene oxide triol made from propylene and ethylene oxides and gylcerine and having a theo retical number average molecular weight of about 4700 and a hydroxyl number of about 35.9. The alkylene oxide units are present primarily in blocks and the end units are substantially all ethylene oxide units, i.e., the ethylene oxide is used to "cap" the triol. Based on its total weight1 this triol contains about 14 wt-Z ethylene oxide. (Such a polyol is commercially available from Union Carbide under the trade name Niax 11-27). Polyol C - Polypropylene glycol, a polyether diol having a theoretical number average molecular weight of¯4000 and a hydroxyl number of 28.0. Typically, this diol has a viscosity (250C) of 930 cps and an apparent specific gravity (20/200C) of 1.004.(such as polyol is commercially available from Union Carbide under the trade name Niax PPG-4025). Polyol D - Polypropylene oxide-polyethylene oxide triol made from propylene and ethylene oxides and glycerine and having a theoretical number average molecular weight of about 6,000 and a hydroxyl number of about 26.1. The alkylene oxide units are present primarily in blocks and the end units are substantially all ethylene oxide units, i.e., the ethylene oxide is used to "cap" the trioi. Based on its total weight, this triol contains about 14 wt-% ethylene oxide. (Such a polyol is commercially available from Union Carbide under the trade name of Niax 11-34). Polyol E - Polypropylene oxide-polyethylene oxide polyol made from propylene oxide and ethylene oxide and an 80/20 blend by weight of sorbitol and glycerine, having a theoretical number average molecular weight of about 10,800 and a hydroxyl number of about 28. The alkylene oxide units are present primarily in blocks, and the end units are substantially all ethylene oxide units, i.e., the ethylene oxide is used to "cap" the polyol. The polyol contains about 8 wt-% ethylene oxide units based on the total polyol weight. (Such a polyol is commercially available from Union Carbide under the trade name Niax 16-56). Polyol F - Polypropylene oxide triol made from propylene oxide and glycerine and having a theoretical number average molecular weight of about 3,000 and a hydroxyl number of about 55.4. (Such a polyol is commercially available from Unii?n-arbfde under the trade name Niax Lg-56). Polyol G - Polypropylene oxide - polyethylene oxide triol made from propylene and ethylene oxides and glycerine, and having a theoretical number average molecular weight of 3000 and a hydroxyl number of about 58. The alkylene oxide units are present primarily in blocks and the end units are substantially all ethylene oxide units, i.e., the ethylene oxide is used to "cap" the triol. Based on its total weight, this triol contains about weight per cent ethylene oxide. (Such a polyol is commercially available from BASF Wyandotte Corporation under the trade name Pluracol Polyol 718). Commercially available epoxides useful in the Examples include: Epoxy A, Epoxy B, and Epoxy C - These are homologs of the diglycidyl ether of bisphenol - A. They have epoxide equivalent weight ranges of 177-188, 182-190, and 172-176, respectively. (Commercially available from The Dow Chemical Company under the trade names D.E.R. 330, D.E.R. 331, and D.E.R. 332). Epoxy D - This epoxy resin is a polyglycol di-epoxide available from Dow Chemical Company under the trade name D.E.R. 732. Epoxy E - 3,4 - Epoxycyclohexylmethyl - 3,4 - Epoxycyclohexane carboxylate having an epoxy equivalent weight of 131 to 143 grams/ gram mol of oxirane oxygen. (Such an epoxy resin is commercially available from Union Carbide under the trade name E.R.L.-4221) Epoxy F - A diglycidyl ether of bisphenol A having an epoxy equiv alent weight of 185-200 grams per gram mole epoxide. (Such as epoxy resin is commercially available from Celanese Corporation under the trade name Epi-Rez-510) * Epoxy G - Butyl glycidyl ether, a mono-epoxide having an epoxy value of 0.67-0.77 equivalent per 100 grams and a weight of 130-149 grams per gram mole epoxide. (Available commercially from Ciba-Geigy under the trade name ARALDITE RD-1). Epoxy H - 1,4 - Butanediol diglycidyl ether, a di-epoxide having an epoxy value of 0.75 equivalents per 100 grams and a weight of 134 grams per mol of epoxide. (Available commercially from Ciba-Geigy under the trade name ARALDITE RD-2). The ILD and TES characteristics of foams in the Examples were measured using ASTM D1564-71 standard test methods. The ILD test EMI23.1 basically involves measuring the pressurel(pounds per square inch) necessary to compress a foam sample of standard size to a specified percentage of one of its original dimensions. The TES test basically involves compressing a foam sample of standard size to a solid film before the foam sets, and measuring the tensile strength of the film EMI23.2 (pounds per square inch-gravity). In carrying out the KOH titration test, the amount of unreacted carboxyl groups in a product is determined by direct titration with an alcoholic solution of EMI23.3 normal KOH using Methylene Blue as an indicator (pew). Unreacted carboxyl groups are calculated in units of milligrams of KOH per gram of the sample. A KOH equivalent ranging from o to about 3 indicates that most carboxyl groups of any carboxylic compounds used in the reactions have been reacted, e.g., with hydroxy moieties. A KOH equivalent of about 4 or greater (more particularly 7 or greater), indicates that a significant amount of free carboxyl groups remain unreacted, as is the case in half-esters. The free epoxy content of a reaction mixture may be determined using the potassium iodide method. This method is describeff in detail in Lee and Neville, Handbook of Epoxy Resins (McGraw-Hill Publishers, New York 1967) at page 4-18. It may also be determined using the pyridinium hydrochloride method. A sample is reacted with an excess of pyridinium hydrochloride and the unreacted HC1 is titrated with methanolic NaOH to a pink endpoint. The epoxide content is determined by calculation of the amount of pyridinium hydrochloride consumed during the reaction. In order to correct for inaccuracies due to the presence of any acid in the sample itself, an identical sample is then reacted with pyridine instead of pyridinium hydrochloride and the acid value is added to the calculation for epoxy content. (See Critchfield, F.E., Organic Functional Group Analysis; Vol. 8 in International Series of Monographs on Analytical Chemistry, (MacMillan Co., New York 1963), P. 134; and Mitchell, J., et al, Organic Analysis, Vol. 1, (Interscience Publishers, New York 1953), p. 144. Unsaturation in an adduct or polymer-polyol may be determined using the dodecyl mercaptan method. (NMR could alternatively be used). Standard reagents including the following are prepared: (1) 25 grams of N-dodecyl mercaptan in one liter of ethanol; (2) 50 grams of potassium anhydride in 1 liter of ethanol; and (3) a0.05 to.01 Normal iodine solution in aqueous potassium iodide. An adduct or polymer-polyol sample weighing about 6.5 grams is added to a 250 ml iodine flask containing 50 ml of ethanol. After dissolution of the sample, 25 ml of alcoholic mercaptan solution is pipetted into the flask and neutralized with potassium hydroxide (the potassium anhydride solution). One additional milliliter of potassium anhydride is then added as a catalyst. After allowing the mixture to stand for about 2 minutes, the mixture is acidified with 1-2 ml of glacial acetic acid and diluted with an additional 25 ml of ethanol. The solution is titrated with the standardized iodine solution to a faint yellow endpoint. A blank is run using the same procedure, without adding adduct or polymer-polyol sample and with no potassium hydroxide. The millimoles of unsaturation per gram of the sample are calculated as follows: millimoles unsaturation X (B-A) N W B = milliliters of iodine required to titrate blank A - milliliters of iodine required to titrate the sample N - Normality of the iodine solution W - Weight of the sample (See Kohthoff and Belcher, Volumetric Analysis, Vol. 2 (Interscience Publishers, N.Y. 1957) pp. 389-390). SUMMARY OF FOAM FORMULATIONS - Examples 1-27 In each of the examples, foams were produced by reaction of the adduct or the polymer-polyol with TDI. The monomer uses for the polymerpolyol was styrene/acrylonitrile in each case. Example Adduct Polymer-Polyol Epoxy Polyol Epoxy Polyol 1,10 (Control) - - - A 2 A A - - 3 - - A A 4 B A - 5 - - B A 6 C A - 7 - - C. A 8 D A 9 - - D A 11,13,15 E A - 12,14,16 - - E A 17 (Control) - - - B 18,20,22 E B - 19,21,23 - - E B 24 F A - - 25 - - F A 26 A C - 27 - - A C EXAMPLE 1 (Control and Standard Method For Examples) (a) Preparation of polymer-polyol. As taught in my prior patents, polymer-polyols can be prepared as follows: 584 grams of polyol A [Pluracol 380] (viscosity of 1300 EMI27.1 are placed in a react ton vessel bf suitable dimensions. The reactor is equipped with a stirrer, thermometer and opening for reactant feed. Monomer is fed from a separatory funnel together with a vinyl polymerization catalyst, by means of a proportioning pump. The typical monomer feed comprises 126.8 grams of styrene, 74.0 grams of acrylonitrile angf.2 grams of an azo catalyst [Vazo "64"]. The polyol reactant is heated to a temperature of about 100"C, monomer mixture is then fed into the reactor at a rate of about 4 EMI27.2 After all of the monomer mixture has been fed, the reaction mixture is maintained at about 1400C for 2 hours. The polymer-polyol is now ready for use in the polyurethane-forming reaction. (b) Production of polyurethane foam In a typical process, 100 grams of the polymer-polyol is mixed with 1.0 grams of a foam stabilizer [Union Carbide Silicone No. 6202], 0.2 ml of stannous octoate catalyst, 0.125 ml of an isocyanate-reaction catalyst for urethane formation [Union Carbide Niax Catalyst A-6] and 54.0 grams of toluene diiosocyanate (TDI) (about 20% of the 2,6 isomer and about 80t of the 2,4 isomer). To this mixture were added 4.5 grams of water to decompose the TDI to form C02 as small bubbles and initiate foam formation. The foam is poured into a suitable form; in about 5 minutes, maximum foam height is attained and the rate of expansion is measured. The product is then heated for about 2 hours at 1000C for full reaction, allowed to cool to room temperature and tested the next day. EMI28.1 The foam product of this example had a density of(2.53 lb.ft.3L and EMI28.2 ILD's of (56.2) and (131.3 1b./50 in.ê) after 25% and 65% compressions, respectively. Example 2 Polyol A, 750.0 grams was blended with epoxy A, 37.5 grams, and the mixture was heated for 3 hours at 600C to provide an adduct having an unreacted epoxy content of 0.3 moles eDoxv Der k. total and a viscosity of 2,300 EMI28.3 A polyurethane foam was produced in the manner described in Example 1, part (b), except that thevl;D0 grams of polymerpolyol were replaced by 100 grams of the epoxide/polyol adduct. The EMI28.4 resulting foam had a densitv off2.3 lj./'ft.3iand ILD's EMI28.5 (175.0 lb./50 in. ') at 25% and 65% compressions, respectively. Example 3 Example 1, part (a), was repeated except that the 584 grams of polyol A were replaced by 584 grams of the epoxide-reacted polyol of Example 2. The resulting EMPP had a viscosity of 1,700 EMI28.6 <tb> eps <SEP> and <tb> was used in place of the polymer-polyol in part (b) of Example 1. The final foam EMI28.7 product had a density of(2.6 lb,./ft.3)and ILD's oftl68.8)and(381.3 V. lb./50 in.ê)at 25X and 65% compressions, respectively. Examples 4 and 5 These examples correspond to Examples 2 and 3, respectively, except that epoxy A was replaced by epoxy B. The adduct viscosity was 2,250 EMI28.8 and the EMPP viscosity was 8,705 EMI28.9 <tb> k <SEP> efts. <SEP> The <tb> physical properties of the resulting foams are summarized in Table 1. Examples 6 and 7 These examples correspond to Examples 2 and 3, respectively, except that epoxy A was replaced by epoxy C. The adduct viscosity was 2,200 EMI28.10 and the EMPP viscosity was 9,250 EMI28.11 <tb> The <tb> physical properties of the resulting foams are summarized in Table 1. Examples 8 and 9 These Examples correspond to Examples 2 and 3, respectively, except that epoxy A was renlaced by epoxy D. The adduct viscosity was 2.200 EMI29.1 and the EMPP;viscosity was 11,600 EMI29.2 <tb> cups. <SEP> The <tb> physical properties of the resulting foams are summarized in Table 1. EMI29.3 <tb> <SEP> TABLE <SEP> 1 <tb> <SEP> Foam <SEP> Density <SEP> ILD,(lb./50 <SEP> in.2) <tb> Example <SEP> No. <SEP> t <SEP> ( <SEP> lb./ft.) <SEP> ) <SEP> at <SEP> 25X <SEP> compression <SEP> t <SEP> 65Z <SEP> compression <tb> <SEP> 1 <SEP> Control <SEP> < <SEP> (2.537 <SEP> t{a.4 <SEP> &commat; <SEP> i <SEP> t56) <SEP> XdP <SEP> > <SEP> l3 <SEP> /4 qn <tb> <SEP> 2 <SEP> Adduct <SEP> t2.3) <SEP> ECµ <SEP> | <SEP> I8l63 <SEP> 3- <SEP> 75) <SEP> 24 <SEP> 6 <tb> <SEP> 3 <SEP> EMPP <SEP> (2-6) <SEP> 4 <SEP> 6 <SEP> ;169) <SEP> 2wy <SEP> ; <SEP> t381) <SEP> s br <SEP> } <tb> <SEP> 4 <SEP> Adduct <SEP> t2.39) <SEP> 3t <SEP> 24 <SEP> tf.I <SEP> <SEP> 4 > <SEP> S <SEP> \216) <SEP> 3 <tb> <SEP> 5 <SEP> EMPP <SEP> (1.67) <SEP> a <SEP> 2 <SEP> ll2?5?. <SEP> (250) <SEP> 357/ <tb> <SEP> 6 <SEP> Adduct <SEP> t2-58) <SEP> 4X. <SEP> 2eP <SEP> \ <SEP> 78) <SEP> aq0 <SEP> ndr <SEP> , <SEP> (169)azo <tb> <SEP> 7 <SEP> EMPP <SEP> (3.25) <SEP> z-G <SEP> (200) <SEP> 2PÇ <SEP> 1378/ <SEP> 531. <tb> <SEP> 8 <SEP> Adduct <SEP> (1.86) <SEP> 2 <SEP> 9. <SEP> # <SEP> t502 <SEP> o9) <SEP> t109) <SEP> / <SEP> S <SEP> 3-3 <tb> <SEP> 9 <SEP> EMPP <SEP> k2.s3)o.L < 6' <SEP> k175) <SEP> 2b <tb> As is evident from the data of Table 1, the introduction of epoxide into the polyol or polymer-polyol significantly increases the ILD of the resulting foams over that obtained when the epoxide is omitted as in Example 1. As is also evident, however, the inclusion of the epoxide in the form of a polymer-polyol as in the odd-numbered Examples in Table 1 is a dramatic improvement in ILD over either the control polymerpolyol product or the epoxy-reacted polyol of the even-numbered Examples. Example 10 (Control) Example 1. was reseated except that the control foam had a density EMI29.4 oft2.53 lb./ft.J) and ILD's of(56.2)and(131.3 lb.j50 in.2 art 25% and 65X compressions, respectively. Examples 11 and 12 Examples 2 and 3, respectively, were repeated except the epoxy compound was epoxy E at the 2% level rather than the 5 level; the polyol employed was from the same batch used for Example 10. The adduct had a viscosity of 1,800 EMI29.5 <tb> <SEP> Pa <tb> cpo. <SEP> The <tb> foam properties are set forth in Table 2. Examples 13 and 14 Examples 2 and 3, respectively, were repeated except that the epoxy compound was epoxy E. The adduct had a viscosity of 1,880 EMI30.1 <tb> cw <tb> cups. <SEP> The <tb> foam characteristics are set forth in Table 2. Examples 15 and 16 Examples 2 and 3, respectively, were repeated except that epoxy E was employed instead of epoxy A at a a 10t level. The adduct had a viscosity of 1,860 EMI30.2 <tb> ncFb,/r <tb> reps. <SEP> The <tb> foam properties are set forth in Table 2. EMI30.3 <tb> <SEP> TABLE <SEP> 2 <tb> <SEP> Foam <SEP> Density <SEP> w <SEP> r) <SEP> De <SEP> nsty <tb> Example <SEP> No. <SEP> {lb./ft.J) <SEP> ib. <SEP> at <SEP> 25Z <SEP> coworessflon <SEP> at <SEP> 65Z <SEP> compressio <tb> <SEP> ft <SEP> co' <SEP> ression <SEP> at <SEP> 65% <SEP> com <SEP> ressio <tb> <SEP> 10 <SEP> Control <SEP> ('2.53) <SEP> t(.Lr( <SEP> C565 <SEP> (131) <SEP> 131 <SEP> . <tb> <SEP> 11 <SEP> Adduct <SEP> (2.77) <SEP> 4 <SEP> 2-32 <SEP> t78 <SEP> )/ <SEP> C78)AO <SEP> 162 <SEP> 2? <tb> <SEP> 12 <SEP> EMPP <SEP> 8 <SEP> 2-87) <SEP> 4S-.5 <SEP> o <SEP> e <SEP> 2812 <SEP> 4 <SEP> ('l56 <SEP> }2-1 <tb> <SEP> 13 <SEP> Adduct <SEP> t <SEP> 2.48) <SEP> 39 <SEP> > <SEP> (59) <SEP> CP2-4 <SEP> t1562 <SEP> 2 <SEP> 8d <SEP> S <tb> <SEP> 14 <SEP> EMPP <SEP> (3-87J <SEP> 6X. <SEP> 161. <SEP> t <SEP> 20O) <SEP> zdCg; <SEP> ( <SEP> 381) <SEP> s3s.; <tb> <SEP> 15 <SEP> Adduct <SEP> t2.15 <SEP> 7 <SEP> i <SEP> 34.t <SEP> t <SEP> 50 <SEP> 7 <SEP> 1091,a. <tb> <SEP> 16 <SEP> EMPP <SEP> t2-87 <SEP> / <SEP> 4 <SEP> r. <SEP> vat <SEP> ' <SEP> t <SEP> 97)A% <SEP> 378?3. <tb> Example 17 (Control) Example 1 was repeated except that the polyol was polyol B (Niax 11-27). The polymer-polyol had a viscosity of 7000 cps. The resulting EMI30.4 foam had a density of(2.29 l/ft. 7 and ILD's of t58)and (109 lb./50 in.2) at 252 and 65X compressions, respectively. Examples 18 and 19 Examples 2 and 3, respectively, were repeated except that the polyol was polyol B and the epoxy compound was epoxy E at a 2Z level. The adduct viscosity was 2,040 and the EMPP viscosity was 2,680 EMI30.5 <tb> reps. <SEP> The <tb> foam characteristics are to be found in Table 3. Examples 20 and 21 Examples 2 and 3, respectively were repeated except that the polyol was polyol B and the epoxy compound was epoxy E. The EMPP had a viscosity of 7,400 EMI30.6 <tb> rSo <SEP> n <tb> eps. <SEP> The <tb> foam characteristics are to be found in Table 3. Examples 22 and 23 Examples 2 and 3, respectively, were repeated except that the polyol used was polyol B and the epoxy compound was epoxy E to the 10% level. The foam characteristics are to be found in Table 3. EMI31.1 <tb> <SEP> TABLE <SEP> 3 <SEP> 9 <tb> <SEP> Foam <SEP> Density <SEP> 3 <SEP> ILD,(lb./50 <SEP> in. <SEP> ) <tb> Example <SEP> No. <SEP> (lb./ft.3) <SEP> W <SEP> /u <SEP> at <SEP> 25% <SEP> cotpression <SEP> at <SEP> 65% <SEP> com <SEP> ressior <tb> <SEP> 17 <SEP> Control <tb> <SEP> 18 <SEP> Adduct <SEP> 2.965 <SEP> 13.8t <tb> <SEP> 19 <SEP> EMPP <tb> 20 <SEP> Adduct <SEP> 2.82) <SEP> kr. <SEP> (l64)2O. <SEP> {31l6O2 <tb> <SEP> 3.16J <SEP> iT <tb> <SEP> 21 <SEP> EMPP <SEP> t2.92) <SEP> k6- <SEP> on <SEP> w40-; <SEP> ' <SEP> C <SEP> 1697 <SEP> Z32 <tb> 22 <SEP> Adduct <SEP> (3.16) <SEP> S)0.55 <SEP> l <SEP> 59) <SEP> J72.&commat; <SEP> t144) <SEP> 20Z*S <tb> 23 <SEP> EMPP <SEP> t2.392 <SEP> 3ef.Zv <SEP> ° <SEP> t112) <tb> TENSILE ELONGATION STRENGTH The tensile elongation strength (TES) was measured on foam segments cut from foam produced according to Examples 17 and 21. The test method corresponds to ASTM D 412 with TES measured in pounds per sauare inch. EMI31.2 For the foam of Example 17, TES wast7.8to 10.1 psi) for foam of Example EMI31.3 21, TES was(15.9 to 18.9 psi) Example 24 Polyol A, 750.0 grams, was blended with epoxy F, 48.7 grams, and the mixture was heated for 2 hours at 600C at which point the product exhibited an unreacted epoxy content of 0.J38 moles epoxy per kg. total and a viscosity of 2,400 EMI31.4 <tb> rcw3a <tb> cups. <SEP> A <tb> polyurethane foam was produced from this product in the same manner as in Example 1 except that the 100 grams of polymer-polyol was replaced by 100 grams of the epoxide-reacted EMI31.5 polyol. The resulting foam had a density of (1. 62 lb./ft.)and ILD's of EMI31.6 Q'50.())and(115.0 lb.750 in.2)at 25% and 65t compressions, respectively. Example 25 Example 1 was repeated except that the 584 grams of polyol A were renlaced bv S84 drams of the enoxide-reacted Dolvol of Example 24. The EMI32.1 final foam product had a density of(2.10 1b./ft. ) and ILD's of(112)and EMI32.2 (231 1b./50 in.ê) at 25% and 65% compressions, respectively. Examples 26 and 27 These Examples correspond to Examples 2 and 3, respectively, except that polyol A was replaced by polyol C and epoxy A was replaced by epoxy E. The physical properties of the resulting foams are summarized in Table 4. EMI32.3 <tb> <SEP> TABLE <SEP> 4 <tb> <SEP> Foam <SEP> Density <SEP> ) <SEP> ILD,flb./50 <SEP> in.2) <tb> Example <SEP> No. <SEP> (lb./ft.) <SEP> ;t/aH <SEP> at <SEP> 25X <SEP> compression <SEP> at <SEP> 65% <SEP> compression <tb> <SEP> 24 <SEP> Adduct <SEP> (1.62) <SEP> 2' <SEP> 4L <SEP> (Us; <SEP> 3Qe <SEP> i <tb> <SEP> 24 <SEP> Addict <SEP> t1.62) <SEP> t <SEP> S <SEP> (501 <SEP> 70 <SEP> 3 <SEP> (231) <SEP> a2L.8 <tb> <SEP> 25 <SEP> Adduct <SEP> EMPP <SEP> t <SEP> toy <SEP> 2.10 <SEP> ) <SEP> test6 <tb> <SEP> 26 <SEP> Adduct <SEP> Foam <SEP> product <SEP> tooj <SEP> poor <SEP> to <SEP> test <tb> <SEP> 27 <SEP> EMPP <SEP> (2.63) <SEP> 42- <SEP> odd <SEP> c(2.0? <SEP> (138) <SEP> "49 <SEP> (300) <SEP> 92t.JP <tb> As was described previously herein, it is possible to dissolve the epoxide in the monomer phase and introduce this monomer-epoxide mixture into the polyol in the same manner that the monomer has been added to polyol or epoxy adduct. IJhen following this procedure, an epoxy-modified polymer-polyol is obtained that is fully the equivalent of that obtained by other means described herein and in many ways may be considered superior in regard to uniformity of product and the speed and ease of reaction. Example 28 Polyol B, in an amount of 292 grams, was charged to a reactor and heated to a temperature above 100 C. A monomer mixture was separately prepared comprising 63.4 grams of styrene, 37.9 grams of acrylonitrile and 2.6 grams of Vazo catalyst. To this monomer mixture were added 14.6 grams of epoxy E. This epoxide-monomer mixture was then introduced into the reactor containing the heated polyol mixture at a metered rate of 2 EMI33.1 Throughout the addition, the reaction vessel was agitated and the reaction mixture was maintained in the temperature range of 100 to 12O0C. A white uniform dispersion was obtained in which the particles were on the borderline of visibility. The final product had small uniform particles and a viscosity of 3800 EMI33.2 <tb> CE <SEP> A <SEP> polyurethane <tb> A <SEP> A <SEP> polyurethane <tb> foam produced from this product in the manner described previogsly had EMI33.3 a density of(2.05 lb:/ft.7and ILD's of(l00)andt185 lb./50 in.LBt 25U and 65% compressions, respectively. This example can be carried out effectively with a polyol blend, as well. One such blend comprises 50 parts by weight of polyol E and 50 parts by weight of polyol B. As was noted previously the ILD's were measured by the specific ASTM method; in addition these tests were modified to provide additional information. In a typical case, the foam formulation is poured into a EMI33.4 paper box of dimensions generally(8" x 6.5" x 4/, where the foaming mixture is permitted to rise and set until it is solid. Thereafter it is cured for 2 hours at 1200C. Within two to three hours thereafter a EMI33.5 test specimen measuring(2" x 2" x 29' its cut from the foam and placed between the parallel plates of a compression tester. The product is then compressed by about 25Z based on original height and the ILD is recorded. The specimen is then compressed by 75 of its original height, released and again compressed by 75% of its original height. The sample is then again retested, immediately, at the 25Z compression level at 10 minute intervals for approximately 40 minutes and again on the following day. This modified test permits evaluation of the compression recovery characteristics of the foam. The products of the present invention showed excellent recovery characteristics, particularly when compared to the prior art polyol-based polyurethanes or polymer-polyol based polyurethanes. SUMMARY OF EXPERIMENTAL FINDINGS Following the practices of the present inveption!^greater than 2Z but less than 10% of an epoxide is introduced into polyols with essentially all of the epoxide reacted. In all of the examples, the unreacted epoxy was less than one mole per kilogram of sample; in almost o0 all, the level was below 0.6 mole per kg. In the preferred practice of the invention, the unreacted epoxy is below 0.5 and most preferably below about 0.3 moles per kg. of sample. The resulting adducts can be used in the manner of ordinary polyols to produce improved polyurethane foams directly, or to produce improved polymer-polyols which in turn can be used as polyols in polyurethane forming reactions to provide still greater enhancement of the physical properties of the resulting polyurethane foams. Not only are these adducts essentially free of epoxy activity, they are also essentially free of unsaturation; nevertheless, when incorporated in polymer-polyol reactions, the resulting polyurethane foam has physical characteristics such as ILD and TES which far exceed those of the prior art. These improvements are accomplished without sacrifice of the other properties of urethane foam. It is found that the properties are particularly enhanced when the original polyol contains substantial blocks of ethylene oxide as is typified by the ethylene oxide containing polyols described earlier herein. The improvements are obtained not only with polyepoxides but are also obtained with monoepoxides, or diepoxides which have been converted to monoepoxides by reaction of one of the epoxide radicals with a carboxyl, hydroxyl or the like. It has been shown that the process can be conducted stepwise, in which a polyol and the epoxide are reacted and an ethylenically unsaturated monomer is introduced into the adduct polyol to produce tha phlyper-polyol which in turn is used for the production of polyurethane foams, or alternatively, the epoxide can be dispersed in the monomer which in turn is introduced into the base polyol and reacted therein to form the epoxy modified polymer-polyol directly. As noted the adducts can be used for the production of the polyurethane foams directly and it can be used for the production of the polymer-polyol. In addition, however, these epoxy modified adducts have been found to provide enhanced dispersion stabilizing when included with other polymer-polyols in quantities as low as 1% of the total polymer-polyol mixture. This invention is based on the extremely high reactivity of the epoxy derivatives with the polyol. The epoxy radical can be utilized to- introduce a great variety of intermediate radicals into the polyols. In addition, these improvements in making polymer-polyols are accomplished with the greatest simplicity. While the preferred embodiments of this invention have been discussed above and illustrated by the Examples, it is to be understood that modifications in the invention may be made as knows to those skilled in the art.

Claims: CLAIMS 1. The adduct formed by reaction of a polyol with an epoxy coreactant in which the adduct is essentially free. of unreacted epoxy groups and in which the polyol, the epoxy co-reactant and the adduct are essentially free of ethylenic unsaturation. 2. The adduct of claim 1 in which the amount of said epoxide is greater than 2t but less than 10% by weight. 3. The adduct of claim 2 in which the polyol is selected from the group consisting of poly(oxypropylene)glycols, poly(oxypropylene)polyols, poly(oxybutylene) glycols, poly (oxybutylene) po lyols, poly(oxypropyleneoxyethylene)glycols, and poly(oxypropylene-oxyethylene)polyols and in which the epoxy co-reactant is a diepoxide. 4. A polymer-polyol comprising the reaction product of a polyol having an average molecular weight of at least 500 and that is essentially free of ethylenic unsaturation, an epoxy co-reactant that is essentially free of ethylenic unsaturation, and at least one ethylenically unsaturated monomer which is reactive with free hydroxyl groups of said polyol and said epoxy-co-reactant or adduct thereof by free radical addition polymerization to a substantially linear polymer having a molecular weight of at least 5000. 5. A polyurethane which is the reaction product of a mixture comprising an organic polyisocyanate and (a) an adduct as claimed in claims 1 to 3 and (b) a polymer-polyol as claimed in claim 4 6. A method of producing the adduct as claimed in claims 1 to 3 comprising the steps of providing a mixture of a polyol having an average molecular weight of at least 500 and an epoxy co-reactant, said epoxy co-reactant being essentially completely reacted. 7. A method of producing a polymer-polyol as claimed in claim 6 comprising introducing at least one ethylenically unsaturated monomer which is reactive with free hydroxyl groups of polyol into a reaction vessel containing (a) a polyol having an average molecular weight of at least about 500 that is essentially free of ethylenic unsaturation and epoxy co-reactant that is essentially free of ethylenic unsaturation or (b) an adduct of said polyol and said epoxy co-reactant and polymerizing said monomer by free radical addition polymerization 8. A method in accordance with claim 7 in which said monomer is metered into said reaction vessel at a rate equivalent to approximately the polymerization rate under the conditions existing in said reaction vessel. 9. A method of producing a polyurethane as claimed in claim 5 comprising co-polymerizing-an organic polyisocyanate and the adduct of claims 1 to 3. 10. A method of producing a polyurethane as claimed in claim 5 comprising co-polymerizing an organic polyisocyanate and the polymer-polyol of claim 4. Claims for Austria 1. A method for producing a polyurethane - optionally a polyure'.hane id!U - Dy reacting a mixture of an organic polyisocyanat, an adduct and/or a polymer-polyol, the adduct is formed by reaction of a polyol with an epoxy coreactant and the adduct is essentially free of unreacted epoxy groups and the polyol, the epoxy co-reactant and the adduct are essentially free of ethylenic unsaturation. and the polymer-polyol is the reaction product of a polyol having an average molecular weight of at least 500 and that is essentially free of ethylenic unsaturation, an epoxy coreactant that is essentially free of ethylenic unsaturation, and at least one ethylenically unsatured monomer which is reactive with free hydroxyl groups of said polyol and said epoxy-co-reactant or adduct thereof by free radical addition polymerization to a substantially linear polymer having a molecular weight of at least 5000. 2. The method of claim 1 in which the amount of the epoxide in the adduct is freaker than 2 % but less than 10 z by weight. 3. The method of claim 2 in which the polyol of the adduct is selected from the group consisting of poly(oxypropylene) glycols, poly(oxypropylene)polyols, poly(oxybutylene)glycols, poly(oxybutylene)polyols, poly(oxypropylene-oxyethylene)glycols, and poly(oxypropylene-oxyethylene)polyols and in which the epoxy co-reactant is a diepoxide. 4. The method of claims 1 to 3 in which the polymer-polyol is produced by introducing at least one ethylenically unsatured monomer which is reactive with free hydroxyl groups of polyol into a reaction vessel containing (a) a 'polyol having an average molecular weight of at least about 500 that is essentially free of ethylenic unsaturation and epoxy co-reactant that is essentially free of ethylenic unsaturation or (b) an adduct of said polyol and said epoxy co-reactant and polymerizing said monomer by free radical addition polymerization. 5. The method of claim 4 in which said monomer is metered into said reaction vessel at a rate equivalent to approximately the polymerization rate under the conditions existing in said reaction vessel.

Inventors: STAMBERGER, PAUL
Applicants: UNION CARBIDE CORPORATION
Application year: 1984
Main classification: C08F283
IPC codes: C08G18, C08G59, C09D175