MXPA97002993A - Compositions of politetrametilen-eter-glicoles and polioxi-alquilen-polieter-polioles, which have a low degree of insaturac - Google Patents

Abstract

In accordance with the present invention, polyol compositions are provided, which comprise: (A) a polytetramethylene ether glycol and (B) a polyoxyalkylene polyether polyol initiated by a difunctional active hydrogen compound, having a of unsaturation not greater than 0.04 milliequivalents per gram of polyether-poly

Description

COMPOSITIONS OF POL1TETRAMETHYLENE-ETHER-GLYCOLS AND POLIOXY-ALKYLENE-POLYETER-POLYOLES. THAT HAVE A LOW DEGREE OF INSATURATION Field of the Invention This invention relates to mixtures of poly-tetramethylene polyether glycols and polyoxyalkylene polyether polyols having a low degree of unsaturation of 0.04 or less, and to the molded elastomers, spandex fibers and thermoplastic polyurethanes obtained therefrom. . BACKGROUND OF THE INVENTION Polyurethane elastomers often use one or more polytetramethylene ether glycols (PTMEG), as well as a polyol component, to react with one or more polyisocyanates, such as MDI, because they can impart to the elastomer the high level of mechanical properties required for specific applications. PTMEGs are often used for such applications where high tensile strength, low compressive strength, high resilience and / or high modulus of elasticity are required. PTMEGs, however, can be difficult and expensive to obtain, due to the availability of starting materials and the formation of unwanted reaction by-products during synthesis.

Therefore, it would be convenient to provide polyol compositions that can be used to make high quality polyurethane elastomers, while reducing the amount of the required PTMEGs. SUMMARY OF THE INVENTION Thus, according to the present invention, polyol compositions are provided which comprise: (A) a polytetramethylene ether glycol and (B) a polyalkylene polyether polyol initiated by a difunctional active hydrogen compound, which has a degree of unsaturation not greater than 0.04 milliequivalents per gram of polyether polyol. The polyol compositions, according to the present invention, can be used for the manufacture of polyurethane elastomers by means of the one-stage technique or a prepolymer technique. The elastomers based on the polyol compositions, according to the invention, exhibit a good combination of properties, such as tensile strength, solidification upon compression, resilience and / or a modulus of elasticity, which often previously required the use of the Pure PTMEG. Other properties, such as elongation and resilience, can often be improved using the mixed compositions of the invention. Thus, in one embodiment of the invention, a prepolymer obtained by the reaction of a polyol composition comprising at least the PTMEG, described above, and a polyoxyalkylene polyether polyol having a degree of unsaturation is introduced. 0.04 or less, with an organic polyisocyanate. The prepolymer can be terminated in isocyanate by the addition of a sub-stoichiometric amount of the polyol composition to the isocyanate, or hydroxyl-terminated by the addition to the isocyanate of a molar excess of the polyol composition. In another embodiment of the invention, an elastomer obtained by the reaction of an organic di- or polyisocyanate, with the polyol composition, optionally in the presence of a functional hydroxyl and / or amine chain extender, is supplied at a ratio of NCO: OH equivalent of at least 1.5: 1, where the polyol composition consists of at least PTMEG and a polyoxyalkylene polyether polyol, which has a degree of unsaturation of 0.04 or less. This polyol composition of the invention can be a major component of the polyol of the reaction mixture that forms the urethane elastomer (i.e., the one-step method) or can first be incorporated into a prepolymer, prior to incorporation into the reaction that forms the urethane elastomer (ie, the prepolymer methods). DESCRIPTION OF THE PREFERRED EMBODIMENTS The PTMEGs, useful in the practice of the invention, generally have a number average molecular weight ranging from 500 to 5000, preferably from 800 to 3000, more preferably from 1000 to 2600. The techniques for the manufacture of PTMEGs are well known in the art, as described in the patents of E. U. A., No. 4,294,997 and 4,213,000, the descriptions of which are incorporated herein by reference. Examples of useful PTMEGs include POLYTHF® 650, POLYTHF® 1000, POLYTHF® 2000 and POLYTHF® 2900. PTMEGs are generally synthesized by a ring opening chain extension reaction of monomeric tetrahydrofuran (THF). In a well-known method, the ring opening reaction is catalyzed by fluorosulfonic acid, followed by hydrolysis of the sulfate ester groups and extraction of the acid water and then neutralization and drying. In many cases, the PTMEG will be solid at room temperature, due to its high degree of crystallinity. In case it is desired to use the liquid PTMEG at room temperature, the THF can be copolymerized with alkylene oxides (also known as cyclic ethers or onoepoxides), as suggested in US Patent No. 4,211,854, incorporated herein by reference. reference. Such copolymers have a heteric structure of block A-B-A, in which blocks A are random copolymers of tretra-hydro-furan and alkylene oxides, and block B is composed of polytetra-ethylene oxides.

Cyclic ethers, copolymerizable with tetrahydrofuran are not particularly limited, provided they are cyclic ethers capable of ring-opening polymerization and may include, for example, 3-membered cyclic ethers, 4-membered cyclic ethers, ethers cyclics such as tetrahydrofuran derivatives, and cyclic ethers such as 1,3-di-oxolane, trioxane, etc. Examples of cyclic ethers include ethylene oxide, 1,2-butene oxide, 1,2-hexene oxide, 1,2-tert-butyl-ethylene oxide, cyclohexene oxide, 1,2-octene oxide, cyclohexylethylene oxide, styrene oxide, phenyl glycidyl ether, allyl glycidyl ether, 1,2-decene oxide, 1,2-octadecene oxide, epichlorohydrin, epibromohydrin, epiiodohydrin, perfluoro-propylene oxide, cyclopentene, 1,2-pentene oxide, propylene oxide, isobutylene oxide, trimethylene-ethylene oxide, tetraethylene-ethylene oxide, styrene oxide, 1,1-diphenylethylene oxide, epifluorohydrin, epichlorohydrin, epibromohydrin, epiiodohydrin, oxide of 1,1,1-trifluoro-2-propylene, 1,1,1-trifluoro-2-methyl-2-propylene oxide, 1,1,1-trichloro-2-methyl-3-bromo-2 oxide -propylene, 1, 1, l-tribromo-2-butylene oxide, 1,1, 1-trifluoro-2-butylene oxide, 1,1-l, trichloro-2-butylene oxide, oxetane, 3-methyl oxetane , 3,3-dimethyloxetane, 3,3-diethyloxetane, 3, 3-bis (chloromethyl) oxetane, 3, 3-bis (bromo-methyl) oxetane, 3, 3-bis (iodomethyl) oxetane, 3, 3-bis (fluoromethyl) oxetane, 2-methyltetrahydrofuran, 3-methyltetra- hydrorofuran, 2-methyl-3-chloromethyltetrahydrofuran, 3-ethyl-tetrahydrofuran, 3-isopropyltetrahydrofuran, 2-isobutyl-tetrahydrofuran, 7-oxabicyclo (2, 2.1) -heptane, and the like. The content of the copolymerized cyclic ether, if present, in a PTMEG, may be within the range of 5 to 95% by weight, but, when a copolymerized polyether glycol is obtained, containing oxytetra-methylene groups as a main component , which is effective as the soft segment in the polyurethane elastomer, such as spandex, the amount of the cyclic ether in block A copolymerizable with THF is generally 30 to 70% by weight. In the case that one selects cyclic ethers that randomly copolyze, with the THF through the total copolymer, the amount of the cyclic ether can vary from 5 to 60% by weight of the copolymer. Additionally, in the synthesis reaction of the PTMEG, a part of the starting THF can be replaced with an oligomer of the PTMEG, as the starting material. In addition, in the synthesis reaction of the copolymerized polyether glycol, a PTMEG oligomer or a polyether glycol oligomer to be synthesized can be added as a part of the starting material to carry out the reaction. In such a case, the oligomer will generally have a lower molecular weight than the polymer to be synthesized. More specifically, an oligomer having a number average molecular weight in the range of 100 to 800 can be used, when a polymer with a number average molecular weight of 1000 or more is synthesized, and an oligomer with an average molecular weight of number from 100 to 2000, when a polymer with a number average molecular weight of 3000 or more is synthesized. Likewise, an oligomer separated by fractional extraction or vacuum distillation of the PTMEG or the synthesized copolymerized polyether glycol can be employed. Such an oligomer can be added in an amount of up to 10% by weight in the starting monomer. The degree of polymerization tends to decrease as the reaction temperature is increased and, therefore, also in view of the polymerization yield, the polymerization temperature should preferably be between -10 ° C to 120 ° C, more preferably 30 to 80 ° C. If the temperature exceeds 1202C, performance decreases. The time required for the reaction is generally between 0.5 and 20 hours, although it may vary depending on the amount of the catalyst and the reaction temperature. The reaction can be carried out in any generally employed system, such as a tank type or tower type vessel. It is also possible to use the system in batches or continuous.

The catalysts used in the preparation of the PTMEG are well known and include any cationic catalyst, such as strongly acid cation exchange resins, smoking sulfuric acids and boron trifluorides. The polyol blends of the present invention comprise a polyoxyalkylene polyether polyol, initiated by a difunctional active hydrogen compound. Polyoxyalkylene polyether polyols initiated by a difunctional compound of active hydrogen, useful in the practice of the invention, should have average number molecular weights suitable for the particular application and generally from 400 to 7000, preferably from 1000 to 6500, more preferably from 1500 to 3500, and especially preferred from 2000 to 3000. The hydroxyl numbers of the polyoxyalkylene polyether polyols used in the invention correspond to the desired number average molecular weight of the formula: OH = (f) 56.100 / weight equivalent. For most applications suitable hydroxyl numbers for the polyoxyalkylene polyether polyol range from 15 to 250 and more often from 25 to 120. The polyoxyalkylene polyether polyols used in the invention have a degree of unsaturation of 0.04. milli-equivalents of KOH / g of polyol or less, preferably 0.03 or less, more preferably 0.02 or less.

The structure of the polyoxyalkylene polyether polyol contains a core of a difunctional active hydrogen initiator compound, which contains at least two hydrogen atoms reactive to the alkylene oxides. Specifically, the reactive hydrogen atoms in the initiator compound must be sufficiently labile or unstable to open the epoxide ring of the ethylene oxide. The initiator compound has a relatively low molecular weight, generally less than 400, more preferably less than 150. Examples of initiator compounds, useful in the practice of this invention, include, but are not limited to, ethylene glycol, propylene glycol, diethylene glycol, di-propylene glycol, 2,3-butylene glycol, 1,3-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, and the like. Another class of reactive hydrogen compounds that may be used are alkyl amines and alkylene polyamines, which have two reactive hydrogen atoms, such as methylamine, ethylamine, propylamine, butylamine, hexylamine, ethylene diamine, diethylene diamine, and the like. , 6-hexanediamine, and the like. It may be necessary to select catalysts or adjust the reaction conditions to allow the amine hydrogens, both primary and secondary, to open the ring of the alkylene oxides, in order to make the monoamines difunctional. Conversely, it may be necessary to select catalysts or adjust the reaction conditions to favor the primary amine hydrogens in order to obtain difunctional diamines. Cyclic amines, such as piperazine, 2-methylpiperazine and 2,5-dimethylpiperzine, can also be used. The amides constitute one more class of such reactive hydrogen compounds, such as acetamide, succinamide and benzenesulfonamide. Yet another class of such reactive hydrogen compounds are dicarboxylic acids, such as adipic acid and the like. The initiator may also be one that contains different functional groups having reactive hydrogen atoms, likewise, such as glycolic acid, ethanolamine, and the like. In a preferred embodiment, the polyoxyalkylene polyether polyols used in the invention contain at least one hydrophobic block, obtained from propylene oxide, or a mixture of propylene oxide and other cyclic ethers. Such other cyclic ethers are of the type which are hydrophobic with respect to the polyoxyethylene groups; or if they are of a hydrophobic character, they are mixed with the propylene oxide only in those relative amounts that do not render the polyol ineffective for its final application. The hydrophobic block may consist of a homo-block of oxypropylene groups or a block of randomly distributed oxypropylene groups and other oxyalkylene groups. As an alternative to, or in combination with propylene oxide, butylene oxide can also be used, since it also exhibits hydrophobic properties and supplies polyols having a low degree of unsaturation. The polyether of the invention can also be prepared by the addition reaction between a sule initiator compound, directly or indirectly, with a defined amount of propylene oxide, to form an internal block of oxypropylene groups, followed by the subsequent, direct addition. or indirectly, from one or more other oxides. The polyoxyalkylene polyether polyol can contain only ethylene oxide groups, especially if the molecular weight is below 600. However, it preferably contains from 50 to 100% by weight of oxypropylene groups, preferably from 70 to 96. % by weight of oxypropylene groups, based on the weight of all the cyclic ether groups added. In a preferred embodiment of the invention, the propylene oxide is added and reacts directly with the initiator compounds through the sites of the reactive hydrogen atom, to form an internal block of polyoxypropylene groups. The structure of such intermediate compound can be represented according to the following formula: R [(C3H60) w] -2 where R is the initiator core; w is an integer representing the number of oxypropylene groups in the block, such that the weight of the oxypropylene groups is from 50 to less than 100 percent by weight (or 100% by weight if one wishes to obtain a polyol based on only in oxypropylene groups and the initiator), based on the weight of all the added alkylene oxides; and 2 represents the number of reactive sites in the initiator molecule over which the chains of the oxypropylene groups are linked. The polyether polyol may also comprise more than one internal block of oxypropylene groups. By an internal block it is meant that the block of the oxypropylene groups must be placed structurally between the core of the initiator compound and a different block of one or more different kinds of oxyalkylene groups. It is within the scope of the invention to interpose a block of different oxyalkylene groups between the initiator core and the oxypropylene group block, especially if different oxyalkylene groups are also hydrophobic. In a preferred embodiment, however, the internal block of the oxypropylene groups is directly attached to the nucleus of the initiator compound through its reactive hydrogen sites. The polyoxyalkylene polyether polyols used in the invention are terminated in reactive isocyanate hydrogens. These reactive hydrogens may be in the form of primary or secondary hydroxyl groups, or amine group, primary or secondary. In the manufacture of elastomers, it is often convenient to introduce isocyanate reactive groups that are more reactive than the secondary hydroxyl groups. The primary hydroxyl groups can be introduced onto the polyether polyol by the reaction of the polyether polymer that grows with the ethylene oxide. Therefore, in a preferred embodiment of the invention, the polyoxypropylene polyether polyol is terminated with a terminal block of oxyethylene groups. Alternatively, in another embodiment, the polyether polymer of the invention can be terminated with a mixture of terminal, primary and secondary hydroxyl groups, when a mixture of ethylene oxide and, for example, propylene oxide, is used in the manufacture of a terminal auction. The primary and secondary amine groups can be introduced into the polyether polymer by a reductive amination process, as described in U.S. Patent No. 3,654,370, incorporated herein by reference. The weight of the terminal block of oxyethylene groups, when employed, is at least 4 to 30% by weight, preferably 10 to 25% by weight, based on the weight of all compounds added to the initiator.

The method of polyacrylating the polyether polymers of the invention is not limited and can be carried out by anionic, cationic or coordinated mechanisms. Anionic polymerization methods are generally known in the art. Typically, an initiator molecule is reacted with the alkylene oxide, in the presence of a basic catalyst, such as an alkoxide or an alkali metal hydroxide. The reaction can be carried out under an over-atmospheric pressure and an aprotic solvent, such as dimethylsulfoxide or tetrahydrofuran, or in volumetric form. The type of catalyst used for the manufacture of the polyoxyalkylene polyether polyol is also not limited, as long as this catalyst is of the type that produces the polyoxyalkylene polyether polyols having a degree of unsaturation of 0.04 or less, with the average molecular weight in desired number Suitable catalysts include the alkali metal compounds, alkaline earth metal compounds, ammonium and double metal cyanide catalysts, as described in the patent of E. u. A., No. 3,829,505, incorporated herein by reference, as well as the hydroxides and alkoxides of lithium and rubidium. Other useful catalysts include oxides, hydroxides, hydrated hydroxides and salts of barium or strontium onohydroxide.

Suitable alkali metal compounds include those containing sodium, potassium, lithium, rubidium and cesium. These compounds may be in the form of the alkali metal itself, oxides, hydroxides, carbonates, salts of organic acids, alkoxides, bicarbonates, natural minerals, silicates, hydrates, etc., and mixtures thereof. Suitable alkaline earth metal compounds and mixtures thereof include those containing calcium, strontium, magnesium, beryllium, copper, zinc, titanium, zirconium, lead, arsenic, antimony, bismuth, molybdenum, tungsten, manganese, iron, nickel, cobalt and barium. Suitable ammonium compounds include, but are not limited to, those containing the ammonium radical, such as ammonia, amino compounds, for example, urea, alkyl ureas, dicyanodiamide, melamine, guanidine, aminoguanidine; amines, for example aliphatic amines, aromatic amines, organic ammonium salts, for example ammonium carbonate, quaternary ammonium hydroxide, ammonium silicate, and mixtures thereof. The ammonium compounds can be mixed with the aforementioned basic salt forming compounds. Other typical anions may include the halide ions, such as fluorine, chlorine, bromine, iodine, or nitrates, benzoates, acetates, sulfonates, and the like. Of these alkali metals, cesium is the most preferred. Lithium, sodium and potassium are often not as effective in reducing the degree of unsaturation of the polyoxyalkylene polyether polyols at higher equivalent weights. In a preferred embodiment, these polyoxyalkylene polyether polyols are obtained with a catalyst containing cesium. Examples of catalysts containing cesium include cesium oxide, cesium acetate, cesium carbonate, cesium alkoxides of lower alkanols C ^ -Cg, and cesium hydroxide. These catalysts are effective in reducing the unsaturation of the high equivalent weight polyols, which have a large number of oxypropylene groups. Unlike double metal cyanide catalysts, which may also be effective in decreasing the degree of unsaturation of the polyoxyalkylene polyether polyols, the cesium based catalysts do not have to be removed from the reaction chamber before adding the finishing of ethylene oxide in a polyether polyol. Thus, the manufacture of a polyoxyalkylene polyether polyol having an ethylene oxide cap can be carried out through the total reaction with the catalyst based on cesium. The degree of unsaturation can be determined by the reaction of the polyether polymer with mercuric acetate and methanol in a methanolic solution, to liberate methoxy acetoxymercuric compounds and acetic acids. Any left mercuric acetate is treated with sodium bromide to convert this mercuric acetate to the bromide. The acetic acid in the solution can then be titrated with potassium hydroxide, and the degree of unsaturation can be calculated from a number of titrated moles of acetic acid. More specifically, 30 grams of the polyether polymer sample is weighed into a sample flask, and 50 ml of the reactive grade mercuric acetate is added to the sample flask and to a reference flask. The sample is stirred until the contents are dissolved. The sample and reference flasks are allowed to stand for thirty (30) minutes, stirring occasionally. Next, add 8 to 10 grams of sodium bromide to each and stir for two (2) minutes, after which one (1) ml of the phenolphthalein indicator is added to each and titrated with the KOH Standard methanolic l.ON to a pink colored end point. The degree of unsaturation is calculated and expressed as milli-equivalents per gram: (ml of KOH sample - reference KOH) x NKOH - Acidity (A) as meq / g sample weight The correction of the acidity is made only if the acid number of the sample is greater than 0.04, in this case, it is divided by 56.1 to give milliequivalents / gram.

The reaction conditions can be adjusted to those typically employed in the manufacture of the polyoxyalkylene polyether polyols. In general, from 0.005 to about 5 percent, preferably from 0.005 to 2.0 percent and more preferably from 0.005 to 0.5 percent by weight of the catalyst, relative to the polyether polymer, is used. Any catalyst left in the polyether polymers, produced according to the invention, can be neutralized by any of the well known processes described in the art, such as by an acid, adsorption, water wash or ion exchange. Examples of acids used in the neutralization technique include organic acids, solid or liquid, such as 2-ethylhexanoic acid and acetic acid. For ion exchange, phosphoric acid or sulfuric acid can be used. The extraction or adsorption techniques employ clay activity or synthetic magnesium silicates. It is convenient to remove the cationic metal contents at less than 500 ppm, preferably less than 100 ppm and more preferably between 0.1 and 5 ppm. As for the other process conditions, the temperature at which the polymerization of the polyether polymers occurs generally varies from 80 to 1602C, preferably from 95 to 1152C. The reaction can be carried out in a column reactor, a tube reactor, or in batches in an autoclave. In batch processes, the reaction is carried out in a closed vessel under pressure, which can be regulated by a cushion of inert gas and the alkylene oxide feed inside the reaction chamber. In general, the operating pressures produced by the addition of the alkylene oxide vary from 0.7 to 3.5 kg / cm2 gauge. The generation of a pressure greater than 7 kg / cm2 increases the risk of an escape reaction. The alkylene oxides may be fed into the reaction vessel as a gas or a liquid. The contents of the reaction vessel are vigorously stirred to maintain a good dispersion of the catalyst and uniform reaction regimes throughout the mass. The course of the polymerization can be controlled by dosing consecutively of each alkylene oxide until the desired amount is added. When blocks of random or statistical distribution of the alkylene oxides in the polyether polymer are desired, these alkylene oxides may be metered into the reaction vessel as mixtures. The stirring of the contents in the reactor at the reaction temperature is continued until the pressure drops to a low value. The final reaction product can then be cooled, neutralized, as desired, and removed.

The polyol composition of the invention may include additional polyols, in addition to the PTMEG and the polyether polyol, described above. For example, polyols of other functionalities, that is, greater than 2, can be included. These polyols can be prepared as described above, except that a major functionality initiator is used, such as glycerol, trimethylolpropane, pentaerythritol, sorbitol, sucrose, and the like, and amines, such as ethylenediamine, toluenediamine, and the like. . Larger functional polyols may be incorporated either by the physical mixture of the finished polyols or by including a higher functional initiator in a mixture with the difunctional initiator described above, prior to the reaction with one or more alkylene oxides. Thus, a mixture of initiator compounds can be used to adjust the functionality of the primer to a number between integers. If one wishes to manufacture an elastomer that has only a slight degree of entanglement, a high proportion of an initiator, having a functionality of 2, to which relatively small amounts of trifunctional initiator compounds or with higher functionality are added, can be mixed together to achieve an initiator having an average functionality of about 2 to 2.3. On the other hand, a higher proportion of trifunctional or higher initiator compounds can be mixed with a difunctional initiator compound, when a greater degree of entanglement is desired. Other types of polyols can also be included in the polyol composition of the invention. For example, polyester polyols can be added to improve certain mechanical properties of an elastomer, such as the tensile strength and modulus of the urethane polymer. However, for some elastomeric applications, it is preferred to use only polyether polyols, because they can be more stable hydrolytically than polyester polyols, and they are processed well because of their lower viscosities. Other polyols that may be employed, in addition to the polyoxyalkylene polyether polymers of the invention, are hydroxyl-terminated hydrocarbons, such as polybutadiene-polyols, when a high degree of hydrophobicity is desired. Castor oil and other natural oils can also be used. In addition, polycaprolactones can be used to increase the tensile strength of elastomers. Other polyether polyols can be added and it is preferred that these polyether polyols have a low degree of unsaturation for the optimum mechanical properties of the product. Other ingredients in the polyol composition, in addition to the PTMEG and the polyoxyalkylene polyether polyol, may include other polyols, chain elongation agents or curing agents, catalysts, fillers, pigments, UV stabilizers, and the like. The above-described components of the polyol composition can be mixed together by standard mixing techniques, preferably in a weight ratio of PTMEG: polyether polyol from 20:80 to 95: 5, although higher ratios of 95: 5. If either of the components (A) or (B) is solid, they can be liquefied, preferably by melting, before mixing. Preferably, the polyol composition of the invention should form a homogeneous mixture without a visual phase separation. It may be necessary to adjust the relative molecular weights of either or both components (A) and (B), in order to achieve a homogeneous mixture. Depending on the application of the elastomer, the average real functionality of the mixture must be 1.5 to 3. 0, preferably from 1.95 to 2.3, and as low as 1.95 to 2. 1. In these modalities, polyols having functionalities outside these ranges can be used, as long as the average functionality is within the range. In one embodiment, which is preferred for certain applications, the functionality of the mixture must be maintained at 3.0 or less to avoid excessive loss of elongation, a convenient feature for certain elastomeric applications. In applications where high hardness, high tensile strength and low elongations are desirable, it may be desirable that the actual average functionality of the mixture exceed 3.0. For most elastomeric applications, the number average molecular weight for the polyol composition of the invention can vary from 500 to 4000, preferably from 900 to 3000. The one component elastomers can be cured by air humidity. The two component elastomers can be cured together with chain elongation agents with compounds containing reactive hydrogen of the isocyanate. These chain elongation agents can be contained in the polyol composition. The elastomers can be prepared using the one-step technique or the prepolymer technique. If the prepolymer technique is used, the polyol composition will normally be free of a chain extender during the manufacture of the prepolymer. This prepolymer is then reacted with any remaining polyol composition, which, at that point, contains a chain extender. In the process of a step, the polyisocyanate is reacted at the start with a polyol composition containing the chain extender. Chain-lengthening agents can be and are typically used in the preparation of polyurethane elastomers. The term "chain extender" is used to mean a compound of relatively low equivalent weight, usually less than about 250 equivalents by weight, preferably less than 100 equivalents by weight, having a plurality of isocyanate reactive hydrogen atoms. The chain extension agents may include water, hydrazine, aliphatic or aromatic primary and secondary diamines, amino alcohols, amino acids, hydroxy acids, glycols or mixtures thereof. A preferred group of chain alcohol extension agents include water, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,10-decanediol or m-, p-dihydroxycyclohexane, diethylene glycol, , 6-hexanediol, glycerin, trimethylolpropane, 1,2,4-, 1,3,5-trihydroxycyclohexane and bis (2-hydroxyethyl) -hydroquinone. A preferred group of amine chain-lengthening agents include 1,3-diaminocyclohexane, piperazine, ethylene diamine, propylene diamine, and mixtures thereof. Examples of secondary aromatic diamines include aromatic diamines substituted with N, N'-dialkyl, which may be unsubstituted or substituted on the aromatic radical by alkyl radicals, having from 1 to 20, preferably from 1 to 4 carbon atoms in the N-alkyl radical, for example N, N * -diethyl-, N, N'-di-sec-pentyl-, N, N'-di-sec. -hexyl-, N, N'-di-sec. -decyl- and N, N'-dicyclohexyl-p- and m-phenylenediamine, N, N'-dimethyl-, N, N -diethyl, N, N'-diisopropyl-, N, N'-di-. sec. -butyl- and N, N * -dicyclohexyl-4,4'-diaminodiphenylmethane and N, N'-di-sec-butylbenzidine. The amount of the chain extender used can vary depending on the desired physical properties of the elastomer. A larger proportion of the chain extender and the isocyanate supplies the elastomer with a greater number of hard segments, which result in an elastomer having a higher rigidity and heat distortion temperature. Minor quantities of the chain extender and the isocyanate result in a more flexible elastomer. In general, about 2 to 70, preferably 10 to 40, portions of the chain extender can be used per 100 parts of the polyether polymer and the PTMEG and any other higher molecular weight isocyanate reactive component. Catalysts can be used to accelerate the reaction of the hydroxyl group-containing compounds with the polyisocyanates. Examples of suitable compounds are the cure catalysts which also function to shorten the tack time, promote resistance without treatment and prevent shrinkage. Suitable curing catalysts include organometallic catalysts, preferably organic tin catalysts, although it is possible to use metals, such as lead, titanium, copper, mercury, cobalt, nickel, iron, vanadium, antimony and manganese. Suitable organometallic catalysts, exemplified herein by tin as the metal, are represented by the formula RnSn [X-R1-Y] 2, wherein R is an alkyl or aryl group C ^ -Cg, R1 is a methylene group CQ-CIQ optionally substituted or branched with a Cl-C4 alkyl group, Y is hydrogen or a hydroxyl group, preferably hydrogen, X is methylene, a group -S-, a group -SR2COO-, -SOOC-, a group 03S- or a group -00C-, in which R2 is alkyl C1-C4, n is 0 or 2, with the condition that R1 is CQ only when X is a methylene group. Specific examples are tin (II) acetate, tin (II) octanoate, tin (II) ethylhexanoate and tin (II) laurate; and dialkyl (1-8C) tin salts (IV) of organic carboxylic acids having 1 to 32 carbon atoms, preferably 1-20 carbon atoms, for example, diethyl tin diacetate, dibutyltin diacetate, dibutyl tin dilaurate, dibutyl tin maleate, dihexyl tin diacetate, and dioctyl tin diacetate. Other suitable organic tin catalysts are organic tin alkoxides and salts of mono- or polyalkyl (C ^ -Cg) tin (IV) of inorganic compounds, such as butyl tin trichloride, diethyl-, dibutyl oxides -, dioctyl and diphenyl-tin, dibutyl tin dibuthoxide, di (2-ethylhexyl) oxide, tin and dibutyltin dichloride. However, tin catalysts with tin-sulfur linkages that are resistant to hydrolysis are preferred, such as (C1-C20) dialkyl dimer-diuretes, which include the dimethyl-, dibutyl and dioctyl-tin dimer-receptors. Tertiary amines also promote the formation of urethane bonds and include triethylamine, 3-methoxypropyl dimethylamine, triethylene diamine, tributylamine, dimethylbenzylamine, N-methyl-, N-ethyl- and N-cyclohexyl-morpholine, N, N, N ', N '-tetramethylethylenediamine, N, N, N', N'-tetramethylbutanediamine or NjNjN'-N'-tetramethylhexandiamine, N, N, N '-trimethyl-isopropyl-propyleneamine, pentamethylethylenetriamine, tetraethyldiaminoethyl ether, bis (dimethylamino- propyl) urea, dimethylpiperazine, l-methyl-4-dimethylamino-ethylpiperazine, 1,2-dimethylimidazole, 1-azabicyclo [3.3.0] -octane and preferably 1,4-diazabicyclo [2.2.2] octane, and compounds of alkanolamine, such as triethanolamine, triisopropanolamine, N-methyl- and N-ethyldiethanolamine and dimethylethanolamine. To prevent entrainment of air bubbles in the sealants or elastomers, a mixture of batches may be subjected to degassing at a reduced pressure, once the ingredients are mixed together. In the degassing method, the mixed polyurethane formed ingredients can be heated under vacuum at an elevated temperature, to react or volatilize the waste water. By heating at an elevated temperature, the waste water reacts with the isocyanate to liberate the carbon dioxide, which is removed from the mixture by reduced pressure. Alternatively, or in addition to the degassing process, the ingredients forming the polyurethane can be diluted with solvents to reduce the viscosity of the mixture forming the polyurethane. These solvents should not be reactive and include tetrahydrofuran, acetone, dimethylformamide, dimethylacetamide, normal methylpyrrolidone, methyl ethyl ketone, etc. The reduction in viscosity of the ingredients that make up the polyurethane helps its extrusion capacity. However, for sealing applications, the amount of the solvent must be kept as low as possible, to avoid deterioration of its adhesion to substrates. Other solvents include xylene, ethyl acetate, toluene and Cellosolve acetate. Plasticizers may also be included in the components of side A or B to soften the elastomer and lower its brittleness temperature. Examples of plasticizers include dialkyl phthalates, dibutylbenzyl phthalate, tricresyl phosphate, dialkyl adipates and trioctylphosphate. In addition to solvents or plasticizers, other ingredients, such as adhesion promoters, fillers and pigments, such as clay, silica, fumed silica, carbon black, talcum, phthalocyanine blue, titanium oxide, magnesium carbonate, carbonate of calcium, UV radiation absorbers, antioxidants and HALS, can be added in amounts ranging from 0 to 75 weight percent, based on the weight of the polyurethane. Other fillers include dissolved gels, plasticeles, calcium carbonate graded and coated, urea solids, the reaction product of hydrogenated castor oils with amines, and fibers. The polyurethane elastomers of the invention can be prepared by the prepolymer technique or in a one-step process. The elastomers of the invention can be prepared by the injection molding technique of reaction or in a molding process where the ingredients forming the polyurethane are mixed together and emptied into a mold heated under pressure. Other techniques include those of conventional manual mixing and those of mixing in a low pressure or high pressure impact machine, followed by the emptying of the ingredients that form the polyurethane into molds. In a one-stage process, the PTMEG and the polyoxyalkylene polyether polyol of the invention, the catalysts and other isocyanate reactive components that form the polyol composition (also known as the "side B" components), are reacted simultaneously with an organic isocyanate (components of "side A"). Once the components of side B are mixed together, the urethane reaction begins; and the ingredients are emptied or injected into molds to obtain the molded elastomers, or they can be extruded or spun to obtain thermoplastic polyurethane or spandex fibers. In a prepolymer technique, all or a portion of the PTMEG and the polyoxyalkylene polyether polyol, having an end group of saturation degree of 0.04 or less, and any other isocyanate reactive polyols in the polyol composition, and usually without any chain extenders, they are reacted with a stoichiometric excess of the organic isocyanate to form an isocyanate-terminated prepolymer. Such prepolymers usually have free NCO contents of 0.5 to 30% by weight, and for most elastomeric applications, they have contents of free NCO from 1 to 15% by weight. The isocyanate-terminated prepolymer is then reacted as a component of side A with any remaining component of side B, to form a polyurethane elastomer. In some cases, all components of side B are in the form of a prepolymer terminated in active hydrogen. In other cases, only a portion of the polyol composition is reacted with the stoichiometric excess of the organic isocyanate, to form an isocyanate-terminated prepolymer, which is subsequently reacted with the remainder of the polyol composition, as an elastomer of two components. An isocyanate-terminated prepolymer is usually reacted with the reactive isocyanate functionalities in the polyol composition with an NCO equivalent ratio to OH of at least 1.5: 1. Alternatively, an active hydrogen-terminated prepolymer can be prepared if all or a portion of the PTMEG and the polyoxyalkylene polyether polyol having an end group with degree of unsaturation of 0.04 or less, and any other isocyanate reactive polyol in the composition Polyol, and usually without any chain extenders, are reacted with a stoichiometric deficiency of the organic isocyanate to form a prepolymer terminated in active hydrogen. This prepolymer is then reacted as a component of side B with side components A to form the polyurethane elastomer. In one embodiment of the invention a spandex fiber is manufactured using the blends of the invention. Spandex is, by definition, a urethane-containing polymer, with a hard segment / smooth segment, composed of at least 85% by weight of a segmented polyurethane (or urea). The term "segmented" refers to soft and hard alternative regions within the polymer structure. Spandex is typically produced using one of four different processes: extrusion of the melt, reaction yarn, dry spinning of the solution and wet spinning of the solution. All processes involve different practical applications of basically similar chemistry. In general, a block copolymer is prepared by the reaction of a diisocyanate with the polyol composition of the invention in a molar ratio of about 1: 2 and then extending the prepolymer chain with a low molecular weight diol or diamine, of the equivalence of stoichiometry. If the chain extension is carried out in a solvent, the reaction solution can be wet or dry spun into fibers. The prepolymer can be spun by reaction by extrusion in an aqueous or non-aqueous diamine bath, to start the polymerization and form a fiber or the prepolymer can be extended in the chain with a diol by volume and the resulting block copolymer is extruded in fused form in fibers. The spinning of the melt is conducted in a manner similar to the extrusion of the melt of the polyolefins. The reaction yarn is typically carried out after the reaction of the polyol composition with a diisocyanate to form a prepolymer. This prepolymer is then extruded in a diamine bath, where filament and polymer formation occur simultaneously, as described more fully in the U.S. Patent No. 4,002,711. In another embodiment of the invention, a thermoplastic polyurethane elastomer (TPU) is provided, obtained with the blends of the invention. The TPU is obtained by the reaction of a polyol composition comprising the PTMEG and a polyoxyalkylene polyether diol having a low degree of unsaturation, with the organic diisocyanate to form a linear polymer structure. While other polyols with functionalities greater than 2 can be combined with the diol, these should be used in smaller amounts, if used. It is preferable that the functionality of the initiators used to obtain the polyoxyalkylene polyether polyols is 2, and that no initiator having functionality greater than or less than 2 is used, in order to obtain the linear chain of the polymer. The same type of chain-lengthening agents, as described above, can be used, with the preferred chain-lengthening agents being the difunctional glycols. The reaction can be carried out in a one-step process or by the prepolymer technique. In the process of a step, the untreated ingredients are fed into the reaction zone of an extruder, heated to an effective temperature for polymerization to occur, extruded on a conveyor belt and formed into pellets. The prepolymer technique is similar, except that this prepolymer and the chain extender are the materials fed into the reaction zone of the extruder. The type of extruder used is not limited. For example, double or single screw extruders can be used. The following examples further describe the invention. Materials Polyol A is the adduct of propylene glycol of propylene oxide and ethylene oxide having a terminal cap of 20 weight percent of polyoxyethylene groups and an internal block of polyoxypropylene groups, which have a molecular weight of about 3000, and a degree of unsaturation of 0.069, manufactured using the KOH as the polymerization catalyst. Polyol B is an adduct of propylene oxide-ethylene oxide of propylene glycol, having a terminal cap of 20 weight percent polyoxyethylene groups and a molecular weight of 3000, manufactured using cesium hydroxide as the catalyst of polymerization with a degree of unsaturation of 0.025. Polyol C is an adduct of propylene oxide-ethylene oxide of propylene glycol, which has a terminal cap of 20 weight percent of polyoxyethylene groups and a molecular weight of 2500, made using cesium hydroxide as the catalyst of polymerization and a degree of unsaturation of 0.016.

Polyol D is an adduct of propylene oxide-ethylene oxide of propylene glycol, having a terminal cap to 20 weight percent polyoxyethylene groups and a molecular weight of 1250, manufactured using cesium hydroxide as the catalyst of polymerization at a degree of unsaturation of 0.008 milliequivalents of KOH / g of polyol. PTMEG is a polytetramethylene ether glycol, manufactured from tetrahydrofuran at the designated molecular weight. Examples 1-12 In these examples, compression sets of molded elastomers obtained using mixtures of PTMEG and polyether polyols having a high degree of unsaturation, exceeding 0.04, were compared with mixtures of PTMEG and polyether polyols having unsaturation degrees of 0.04 or less. The diphenylmethane diisocyanate was reacted with the polyether-polyol mixtures in the classes and amounts indicated in the following Table 1, at a six (6) percent free NCO content. The prepolymers were then reacted with the 1,4-butanediol chain extender and molded into 6.35 mm plates in a mold. Each plate was heat cured and then subjected to analysis. The module was tested in accordance with ASTM D790. The tensile strength and elongation percentage, according to ASTM D412, the Gaves tear, according to ASTM 624, using Die C, the percentage of resilience, according to ASTM 2632-79 and the solidification upon compression, in accordance with ASTM D395 to a deformation of 25 percent. The following two Tables (2 and 3) illustrate the retention of the compression sets across the board from 0 to 30 weight percent of the low unsaturation polyether polyol in admixture with the PTMEG. Table 2 illustrates the physical properties of the molded elastomers obtained by the same process, according to Example 1, also using a mixture of PTMEG / Polyol B. Table 3 illustrates the same process, except that it uses mixtures of PTHF 2500 / Polyol C. Table 4 illustrates the physical properties of the molded elastomers obtained by the same process, using mixtures of PTHF / Polyol D.

TABLE 1 Example PTMEG Resistance Module Elongation Strength Resilience Solidification- 100% Hardness at (%) to Shore A Tension Compress Stress 2000 1 80/20 1050 2449 410 441 58 26 88 POLYOL B Comparison A 80/20 869 2443 599 440 55 49 76 POLYOL A 2 70/30 990 2162 427 454 56 29 87 POLYOL B Comparison B 70/30 850 1894 505 366 52 73 78 POLYOL A TABLE 2 Comparison C Example 3 Example 4 Example 5 Example 6 MODULE 100/0 95/5 90/10 80/20 70/30 100% 1059 1034 985 904 857 300% 1812 1613 1675 1360 1224 Tensile Strength 2767 2465 2822 1848 1501% Elongation 468 556 513 494 450 Tear Strength (Serious) 502 509 458 460 375 Shore Hardness A 81 83 80 80 82% Resilience 58 61 26 60 49 Solidification ai Compress, 25% 21 14 9.1 20.2 28.2 TABLE 3 Comparison D Example 7 Example 8 Example 9 Example 10 MODULE 100/0 95/5 90/10 80/20 70/30 100% 1059 1000 953 943 827 300% 1812 1678 1601 1532 1367 Tensile Strength 2767 2450 2461 2318 2035% Elongation 468 481 517 507 517 Tear Strength (Serious) 502 489 459 449 392 Shore Hardness A 81 80 79 81 79% Resilience 58 60 60 58 61 Solidification when compressed, 25% 21 14.9 20.2 19.5 33 TABLE 4 Comparison E Example 11 Example 12 Example 13 Example 14 Example 15 PROPERTY 100/0 90/10 80/20 70/30 60/40 50/50 MODULE 100% 1281 1117 1098 984 888 726 200% 1872 1646 1562 1421 1249 978 Tensile Strength 2650 2734 * 2748 2753 2324 2238% Elongation 278 333 * 351 386 392 513 Tear Strength (Serious) 434 359 347 345 325 337 Shore Hardness A 92 89 90 90 88 90% Resilience 52 52 49 46 41 44 % Solidification when compressed 22 24 25 24 38 47 The results in Table 1 show that the PTMEG mixtures obtained with conventional polyether polyols, using standard potassium hydroxide catalysts, with relatively high levels of unsaturation, drastically increase compression solidification at 70/30 weight ratios. In contrast, the compression solidification of the PTMEG / polyether polyols with low degrees of unsaturation, retain significantly low compression solidifications even when the amount of the low unsaturation polyether polyol is increased to 30 weight percent. The compression solidification at a deviation of 25% does not deviate by more than ± 15, when compared to an equivalent elastomer obtained with the same content of free NCO, which uses only polytetramethylene ether glycol, such as polyol and polyol composition. This was achieved without significant reductions in the other physical properties, such as Shore A hardness, tensile strength, modulus and tear strength. The results in each of Tables 2-4 illustrate that molded elastomers obtained with polyether polyols, which have low degrees of unsaturation, can be used and mixed with the PTMEGs without sacrificing the compression solidifications of the elastomers. The elongation was generally improved with the polyol compositions, according to the invention, and certain samples also demonstrated improved resilience. Also, other physical properties, such as modulus, tensile strength and tear strength were not sacrificed and were adequately maintained throughout the broad range of mixing ratios. The invention has been described in detail with reference to its preferred embodiments, However, it should be understood that variations and modifications may be made within the spirit and scope of the invention.

Claims (22)

1. CLAIMS 1. A polyol composition, which comprises: (A) a polyoxytetramethylene ether glycol and (B) a polyoxyalkylene polyether polyol initiated by a difunctional active hydrogen compound, having a degree of unsaturation not greater than 0.04 milliequivalents per gram of the polyether polyol.
2. 2. The polyol composition according to claim 1, wherein at least 33% of the hydroxyl groups in the polyol (B) are terminated with primary hydroxyl groups.
3. 3. The polyol composition according to claim 1, wherein the polyol is capped with oxyalkylene groups, ethylene oxide derivatives, in an amount of 4 to 30 percent by weight, based on the weight of all the oxyalkylene groups.
4. 4. The polyol composition according to claim 2, wherein the number average molecular weight of the polyol composition is from 500 to 5000.
5. 5. The polyol composition according to claim 4, wherein the The number average molecular weight of the polyol composition ranges from 1000 to 4500.
6. 6. The polyol composition according to claim 1, wherein the average functionality of the polyol composition varies from 1.95 to 2.3.
7. 7. The polyol composition according to claim 6, wherein the average functionality of the polyol composition varies from 1.97 to 2.1.
8. 8. The polyol composition according to claim 1, wherein the polyether polyol has a degree of unsaturation not greater than 0.03 milliequivalents per gram of the polyether polyol.
9. 9. The polyol composition according to claim 1, wherein the polyether polyol has a degree of unsaturation not greater than 0.02 milliequivalents per gram of the polyether polyol.
10. 10. The polyol composition according to claim 1, wherein the polyether polyol has a degree of unsaturation not greater than 0.015 milliequivalents per gram of the polyether polyol.
11. 11. The polyol composition according to claim 1, wherein the weight ratio of glycol to polyether polyol ranges from 99: 1 to 20:80. L2.
12. The polyol composition according to claim 11, wherein the weight ratio of glycol to polyether polyol ranges from 95: 5 to 40:60.
13. The polyol composition according to claim 12, wherein the weight ratio of glycol to polyether polyol ranges from about 90:10 to 50:50, respectively.
14. 14. The polyol composition according to claim 1, wherein the polyether polyol is a diol prepared with a catalyst containing cesium.
15. 15. The polyol composition according to claim 14, wherein the cesium-containing catalyst is cesium hydroxide.
16. 16. The polyol composition according to claim 1, wherein the glycol and the polyether polyol form a homogeneous mixture.
17. 17. A prepolymer, which is the reaction product of a polyisocyanate with a polyol composition, according to claim 1.
18. 18. A prepolymer, according to claim 17, in which this prepolymer ends in hydroxyl and is obtained by the reaction of a stoichiometric excess of the polyol composition with the polyisocyanate.
19. 19. A prepolymer, according to claim 17, in which this prepolymer ends in isocyanate, having a free NCO content of 0.5 to 30 weight percent.
20. 20. An elastomer, which is the reaction product of a mixture comprising: (A) a polyisocyanate, (B) a polyol composition, according to claim 1, and (C) optionally, an extender agent. of active hydrogen chain.
21. 21. An elastomer, which is the reaction product of a mixture comprising: (A) a prepolymer according to claim 19, (B) an active hydrogen chain extender, (C) optionally, a different polyisocyanate of the prepolymer.
22. 22. An elastomer, which comprises the reaction product of: (A) a prepolymer according to claim 18, (B) a polyisocyanate and (C) optionally, an active hydrogen chain extender agent.