MXPA00001485A - Novel polyurethane foam composition having improved flex fatigue - Google Patents

Abstract

The present invention relates to a process for preparing a flexible polyurethane foam from the reaction of a polyisocyanate composition prepared from the reaction of an excess of organic polyisocyanate and a polyether polyol having a high ethylene oxide content and an isocyanate reactive composition comprising a chain extending agent and a combination of a polyether polyol having a high ethylene oxide content and a random copolymer having a high ethylene oxide content, and the product prepared therefrom.

Description

NOVELTY COMPOSITION OF POLYURETHANE FOAM WITH IMPROVED VALUES OF FLEXIBLE FATIGUE FIELD OF THE INVENTION This invention relates to a polyurethane foam with an integral surface expanded by water, prepared from an organic polyisocyanate and two polyether polyols with a high content of ethylene oxide in synergistically effective amounts; an isocyanate reaction system useful for preparing said foams, and their preparation process.

BACKGROUND OF THE INVENTION It is desirable that elastomeric polyurethane foams for applications such as shoe soles exhibit good physical properties, such as abrasion resistance, flexibility and durability. In general, these foams are prepared by reacting an organic substance with a substance containing at least one isocyanate-reactive group in the presence of a catalyst, a blowing agent and a variety of optional additives. The reaction is usually done in a mold where a surface of. higher density at the interface of the reaction mixture and the internal surface of the mo 1 of. At present, one of the most common types of blowing agents used in the preparation of these polyurethane foams are the c 1 or r or f or c a rb u r s (CFCs), for example, freon-11. The soles of footwear composed of these polyurethane foams, particularly by polyurethane foams expanded by Freon, have a very thick surface, are resistant to abrasion, are stable and have excellent properties against bending fatigue. However, as the industry is compelled to reduce, and eventually eliminate, the use of CFCs due to environmental problems, it is necessary to find an alternative expansion agent. Water is an appropriate blowing agent and has been used as an expanding agent to remove lower density polyurethane foams. However, until now, it has been found that water is generally unacceptable as the sole agent of expansion, in particular in the preparation of eap urns used as shoe soles. The density of prepared polyurethane foams with water as the sole agent of expansion it is generally very low to provide the adequate stability and padding required by modern footwear. In addition, shoe soles composed of water-expanded polyurethane foams do not have a thick skin and exhibit very poor flexural fatigue properties. In this way, the shoe soles crack very easily after several bends. This inventor, however, has successfully found a reaction system for preparing a polyurethane foam with a microcellular integral surface completely expanded by water, and has thus resolved the aforementioned problems. More specifically, by using the reaction system of the invention, the polyurethane foam prepared by said system has improved the properties of flexural fatigue, which makes it an ideal material to be used in shoe sole compositions. The inventor has found that improved flexural fatigue properties are obtained if the isocyanate reaction component contains a mixture of two polyols with high ethylene oxide content.

SUMMARY OF THE INVENTION Accordingly, the object of this invention is an integral surface polyurethane foam, prepared by contacting, under effective reaction conditions, a polyisocyanate composition with an isocyanate-reactive composition in the presence of water as the sole agent of the invention. expansion, in which: a) The polyisocyanate composition has a free NCO value between 15% and 25%, and contains an isocyanate-terminated prepolymer which is the reaction product of an excess of an organic polyisocyanate and a first polyether polyol protected by ethylene oxide having an average nominal hydroxyl functionality of 2-6, an equivalent weight between 700 and 5000, "and" an ethylene oxide content of at least 25% by weight, at least 50% by weight of the total ethylene oxide groups that are protected in said polyether polyester b) The isocyanate-reactive composition contains between 6% and 12.5% (w / w) of a chain extender agent and a combination of a second polyether polyol protected by ethylene oxide, and a random copolymer of ethylene oxide and oxide of propylene in effective amounts to form said polyurethane foam; the second polyol protected by polyethylene oxide has a nominal hydroxyl functionality average of 2-3, an equivalent weight between 700 and 5000, and an ethylene oxide content of at least 25% by weight, at least 50% by weight of the total ethylene oxide groups which are protected in the ethylene oxide of the polyether polyol; and the copolymer has a nominal average functionality of 2-3%, an equivalent weight between 700 and 5000, and an ethylene oxide content of at least 65% by weight; and c) The water content as blowing agent is an effective amount to give the resulting polymer with a density varying between 0.1 and 1.1, of specific gravity, in which the weight ratio of the water with the extender agent of Chain varies between 0.01 and 0.20. In a preferred embodiment, 10 to 250 parts by weight of the isocyanate-reactive composition are reacted per 100 parts by weight of the polyisocyanate composition. The object of this invention is also a reaction system composed of the composition of polyisocyanate and isocyanate-reactive composition mentioned above, and water, in which the weight ratio of the water with the chain extender varies between 0.01 and 0.20. In a preferred embodiment, the weight ratio of the isocyanate-reactive composition, and the polyisocyanate composition varies between 0.1 and 2.5. Also, this invention is directed with a process for preparing the polyurethane foam mentioned above.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a design of a shoe sole identified in the invention as Model A, composed of the polyurethane foam of the invention. Figure 2 shows a design of a shoe sole identified in the invention as Modeio B, composed of the polyurethane foam of the invention.

DETAILED DESCRIPTION OF THE INVENTION An object of the invention is an integral surface polyurethane foam, prepared from an isocyanate-reactive composition containing a combination of polyols with a high content of ethylene oxide. More specifically, a polyol is polyether polyol protected by ethylene oxide having an ethylene oxide content at least greater than 25%, in which at least 501, and more preferably at least 75%, of said oxide by weight, ~ is at the end of the chain of. polymers. The other polyol is a random copolymer of ethylene oxide and propylene oxide with an ethylene oxide content of at least 65% p "o ~ r p" e so. These two polyols act "in a manner si ne rgisti co, and when reacted with a chain extender, form an isocyanate-reactive composition, which, after having been" made in reaction with the polyisocyanate composition of the invention ". in the presence of water, it forms a polyurethane foam with a flexible integral surface having excellent abrasion resistance and improved resistance to flex cracking. The polymer surface of the polyurethane foam produced according to this invention possesses a ductile modulus and a resistance to wear and tear and sufficient strength to overcome bending. from 90 ° to 180 ° without cracks on the surface. In this way, it is ideal to be used in shoe soles applications as well as other modeled articles. In this invention, the term "Isocyanate Index" or "Index-NCO" or "Index" refers to the ratio of NCO groups to groups containing hydrogen reactive to the isocyanate present in a formulation, given as a percentage with respect to to the amount of isocyanate theoretically necessary to react with the amount of isocyanate-reactive hydrogen-containing groups used in a formulation: [NCO] x 100% NCO index = [groups containing active hydrogen]In other words, the NCO index expresses the percentage of isocyanates used in a formulation, so an index of 100% represents a ratio of 1: 1 NCO equivalents to groups containing reactive hydrogen at isocyanate It should be taken into account that the isocyanate index as used in the invention is considered from the point of view of the actual foaming process comprising the isocyanate composition and the isocyanate-reactive composition. Any isocyanate group consumed in a preliminary step to produce the prepoiimer or other modified polyisocyanate, or any active hydrogen reacted with isocyanate to produce modified polyols or polymers, are not taken into account in the calculation of the isocyanate index. Only the free isocyanate groups and the groups containing hydrogen reactive to the free isocyanate (including those of water) present in the actual foaming step are taken into account. The term "isocyanate-reactive hydrogen containing groups" used in the invention to calculate the isocyanate index refers to the total amount of amine- and hydroxyl groups present in the reactive compositions in the form of polyols, polyamines and / or water; that is, to calculate the isocyanate index in the foam-forming process itself, it is considered that a hydroxyl group is composed of a reactive hydrogen, and a water molecule is considered to contain two active hydrogens. HE considers that the primary amine and secondary amine groups each contain a hydrogen reactive to isocyanate (available) to calculate the index. "Polyurethane foam" refers to the cellular products obtained by reacting polyisocyanate with the isocyanate-reactive composition by foam-forming agents and, in particular, includes cellular products obtained with water as a reactive foam-forming agent (comprising a reaction of water with isocyanate groups that give urea and carbon dioxide bonds and produce po foams or urethane foams). It is understood that the term "polyisocyanate composition" includes mixtures of isocyanate-terminated prepolymers and free polyisocyanates. Free polyisocyanates can also be added to the prepolymer, provided that the free NCO value of the polyisocyanate composition remains at the level mentioned above. The term "reaction system" refers to a combination of ingredients, in which the polyisocyanate composition is kept in a container separate from the isocyanate-reactive ingredients.

The term "average nominal hydroxyl functionality" is used in the invention to indicate the numerical average functionality (amount of hydroxyl groups per molecule) of the individual polyether polyol ingredients, assuming that this is the average numerical functionality (amount of active hydrogen atoms per molecule) of the initiator (s) used in its preparation, although, in practice, it will often be somewhat smaller due to a lack of terminal saturation. It will be understood that any plural term used in the invention also includes the singular and vice versa, unless otherwise indicated. As mentioned above, polyurethane foams are prepared according to the process of the invention by contacting, under effective reactive conditions, the polyisocyanate composition with the isocyanate-reactive composition in the presence of water as the sole blowing agent. The polyisocyanate composition has a free NCO value between 15% and 25% by weight, more preferably between 17% and 21% by weight. As described in the invention, this composition consists of a prepolymer terminated in an isocyanate. This prepolymer is a reaction product of an excess of an organic polyisocyanate and a polyether polyol protected by ethylene oxide. The organic polyisocyanate that can be used in the invention includes any of the aromatic polyisocyanates, r a 1 i f a t i c, cycloaliphatic, or aliphatic, known to those skilled in the art, particularly those which are liquid at room temperature. Examples of suitable polyisocyanates include 1,6-hexamethyl 1 in diisocyanate, isophorone diisocyanate, 1,4-cyclohexanediane, 4,4'-di-cyclohexyl-1-diisocyanate, 1,5-naphthylene. diisocyanate, 1,4-xixylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and diphenylmethane diisocyanates (MDI), including 4,4'-diphenyl diisocyanate, ( 4,4'-MDI), 2, 4 '-di-phenylene diisocyanate, (2, 4' -MDI), 2, 2 '-difenylmethane diisocyanate, (2,2'-MDI), and polymethylene polyphenylene polyisocyanates (Polymeric MDI), etc. Mixtures of these polyisocyanates can also be used. In addition, pozzolanic variants, ie polyisocyanates, particularly MDI's, modified in a known manner by introducing urethane, allophanate, urea, biuret, carbodium, uretonimine, isocyanurate, and / or oxazolidone residues, can be used. , in the systems of the invention (hereinafter, "variants of MDI" or "modified MDI"). These modified polyisocyanates are well known in the art, and are prepared by reactions known to those skilled in the art. For example, uretonimine carbodiimine modified polyisocyanate is obtained by using carbodiimide promoter catalysts well known in the polyisocyanate composition, to convert isocyanate to cambo d. imidates at temperatures between 50 ° C and 250 ° C, which then reacts with other p i a s a n d a s a n a t a s a n a s a s a s a s a n a b a ctio n s a n a n a b a b a b a b a b a b a b a a uretonimine modified polyisocyanate. Conventional catalysts useful in this conversion in urethamimine-carbodiimine modified polyisocyanates include phospholen-1-oxides and 1-sulfides, diaza- and xa z a-f or s and f or s and f or r inano s, triaryl arsines and trialkyl phosphates described in U.S. Pat. No. 5,284,880 and 4,473,626, both incorporated in the invention by reference. In general, the use of aromatic polyisocyanates in this reaction system is preferred. The most preferred aromatic polyisocyanate is diphenylmethane diisocyanate (MDI), by example, 4,4'-MDI, 2,4'-MDI, polymeric MDI, variants of MDI and their mixtures. The term "polymeric MDI" refers to polymethylene polyphenylene polyisocyanates contained in polyisocyanate compositions, having a functionality of at least 2.5. Polymeric MDIs are for sale and are prepared by the phosgenation of polyamine mixtures obtained from the condensation of aniline and, formaldehyde in appropriate proportions. For the purposes of this invention, MDl's having a functionality between 2,53,5, preferably between 2,5-3,1, are especially convenient. The most preferred MDI is 4, '-MDI or a mixture of 4,4'-MDI and 2,4'-MDI, in which the mixture const e 4,4'-MDI in an amount greater than 85% by weight, more preferably greater than 90% by weight, and more preferably greater than 95% by weight.In addition, polymeric MDI may be present in amounts ranging from 0.4% to 4%, depending on the total weight of isocyanate present It is even more convenient for the organic polyisocyanate to be a mixture of 4,4 '-MDI and 2,4'MDI, as mentioned above, and a modified MDI, particularly a mixture of 4,4'. -MDI and 2,2 '-MDI and an MDI composition modified by the introduction of urethane, allophanate, urea, biuret, c a r b or di imide, isocyanate, oxazolidone, and / or uretonimine residues. In this most preferred embodiment, it is desirable that there be a modified amount of MDI between 5 and 15% by weight of the total amount of isocyanate present in the polyisocyanate composition, and that the amount of 4,4 '-MDI is greater than 85. %, preferably greater than 90% by weight of the total amount of isocyanate present in the oliisocyanate composition, and that the amount of 2,4'-MDI is less than 7.5%, particularly less than 5% by weight of the total amount of isocyanate present in the polyisocyanate composition. In the most preferred embodiment, the organic polyisocyanate consists of 4,4'-MDI, and 2,4 '-MID and a modified mixture of 4,4'-MDI and 2,4'MDI, in which the MDI is modified by uretonimine, in the amounts indicated Polyether polyols useful for preparing the isocyanate-terminated prepolymer contain at least 25% by weight of ethylene oxide groups, more preferably 25% to 35% by weight of oxide groups. ethylene, at least 50%, preferably at least 75%, by weight of these ethylene oxide groups are at the extreme of the polyether polyol (finished). The polyether polyols have an average nominal functionality of 2-6, preferably 2-4. They have a numerical average equivalent weight between 700 and 5000, and a preferred equivalent weight between 10D0 and 4000, more preferably between 1200 and 3500, and more preferably between 1500 and 3000. The polyether polyols that will be used to prepare the isocyanate-terminated prepolymer include the products obtained by the polymerization of ethylene oxide with another cyclic oxide, for example, propylene oxide in the presence of polyfunctional initiators; however, the product must maintain the requirements mentioned above. Suitable initiator compounds contain a plurality of hydrogen atoms and include water and low molecular weight polyols, for example, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, cyclohexane dimethanol, resocinol, bisphenol A, glycerol, trimethylolpropane, 1, 2, 6-hexan tri-ol, pentaerythritol, etc. Mixtures of initiators and / or cyclic oxide can be used. Particularly useful polyether polyols include diols and / or triols of (po 1 i (oxyethoxy in oxypropylene), obtained by the sequential addition of ethylene and propylene oxides to initiators di-tribifonone 1 is, as described in the prior art, mixtures of those diols are also useful. and triols Examples of polyether polyol useful for preparing the isocyanate-terminated prepolymer of the invention include Daltocel® F-481, ie, a diol protected by OE, 1870 equivalent weight, with 27.1% ~ OE (OP moiety), PBA ® 5181, ie, polyether polyol with 27% OE (all terminated), MW (molecular weight) = 3750, nominal hydroxy functionality average 2, etc. The isocyanate-terminated prepolymer is prepared by reacting an excess amount of polyisocyanate with the polyether polyol The amounts of polyisocyanate and polyether polyol used are those which will be effective to obtain a prepolymer with the NCO value indicated by techniques known in the art, for example, the prepolymer can be prepared by reacting the organic polyisocyanate with the polyether polyol, followed by dilution with a modified polyisocyanate, as mentioned in the invention, if any. Or, you can mix the polyisocyanate modified with the unmodified polyisocyanate before reacting with the polyol. The reaction is allowed to take place at temperatures effective to form the prepolymer, for example, between 40 ° C and 100 ° C, and, in general, the use of a catalyst is optional. The relative amounts of organic polyisocyanate and polyol depend on the expected NCO value of the prepolymer, the NCO value of the polyisocyanate and the OH value of the polyol, and can be easily calculated by those skilled in the art. At least 90% of the groups obtained from the reaction of the polyisocyanate and the polyether polyol in preparing the prepolymer are urethane groups. For the prepolymers prepared from this. In this way, it is possible to add small amounts (up to 30% by weight) of polyisocyanate or a variant thereof, as long as the NCO value is maintained in the indicated range mentioned above. The aggregate amount is in general preferably less than 20% by weight based on the total weight of the polyisocyanate composition. The polyisocyanate or added variant can be selected from those mentioned above. Aromatic polyisocyanates, in particular polyisocyanates based on MDI, are preferred. Moreover, it is It is preferable that a modified polyisocyanate is added, more preferably, that the added cyanate is the variant of the MDI used in the reaction with the polyol.The other main component, the isocyanate-reactive composition, consists, inter alia, of a polyether polyol protected by a high content of ethylene oxide ("second polio") In fact, the general characteristics of the polyol described above with respect to the prepolymer is applied to the polyol protected by ethylene oxide used in the isocyanate-reactive composition, except that it has an average nominal hydroxyl functionality of 2-3 and that the polyol is a triol or more preferably a diol.Thus, for example, it has an average equivalent numerical weight between 700 and 5000, preferably between 1000 and 4000 , and more preferably between 1200 and 3500, and even more between 1500 and 3000. It contains at least 25% by weight of ethylene oxide groups, more preferably 25% and 35% by weight of ethylene oxide groups. At least 50%, preferably at least 75% by weight of the ethylene oxide groups are at the end of the polyether polyol (finished).

It is desirable that the polyol protected by ethylene oxide used in the isocyanate-reactive composition be the same as that used in preparing the prepolymer described above. Another component of the isocyanate-reactive composition is the random copolymer of ethylene oxide and propylene oxide. The copolymer has an average nominal hydroxyl functionality of 2-4, preferably 23. Its equivalent weight varies between 700 and ~ 5000, more preferably between 1000 and 3000, and more preferably still between 1200 and 2000. This copolymer also has a high content of ethylene oxide. There is an amount of ethylene oxide greater than 60% by weight of the copolymer, more preferably between 65% by weight and 85% by weight. The copolymers are diols or triols of polyols of poly (oxy-1-ene-ip-1-ene), obtained by the sequential addition of propylene and ethylene oxides to initiators di-ytrif-1-one, as glycols. (for example, ethylene glycol, propylene glycol, diethylene glycol, etc.), cyclohexane dimethanol, cyanol, trimethylolpropane, 1,2,6-hexanetriol, pentaerythritol, etc. Mixtures of primers can also be used.

Examples of copolymers include ARCOL®-2580, ie, a random OE / OP copolymer (containing 75% ethylene oxide initiated by trimethylolpropane), 1335 equivalent weight, etc. As will be explained in detail below, the inventor has ascertained that the combination of two types of polyether polyols with high OE content in the isocyanate-reactive composition acts in an inefficient manner, i.e. the combination of the two polyether polyols result in an integral surface polyurethane foam having unexpected and improved bending properties, typical of a polyurethane foam formed by only one of these polyether polyols present. Thus, each of them is in the composition reactive to the isocyanate in synergistic amounts. In a preferred embodiment, the amount of the second polyol varies between 20% and 80% by weight of the composition reactive to is cTc ianato, more preferably between 40% and 60% by weight of the composition reactive to the isocyanate, more preferably 50% ( • On the other hand, the amount of copolymer is preferably between 1.5% and 23% by weight of the isocyanate-reactive composition, more preferably between 2% and 10% by weight. weight of the isocyanate-reactive composition, more preferably 3% by weight of the composition. In addition to the two types of polyether polyol indicated above, the isocyanate-reactive composition may additionally contain conventional polymeric polyols, such as polyether polyol, in which the content of ethylene oxide is less than 25%. The polyols have a molecular weight between 1000 and 10,000, and a functionality of 2-4, preferably 2-3. These conventional polymer polyols have been described in the prior art and include reaction products of alkylene oxides, for example, metal oxide and / or propylene oxide, with initiators containing 2 to 4 active hydrogen atoms per molecule. Suitable processes for preparing these additional polyether polyols include, for example, those described by urtz in 1859 (see Encyclopedia of Chemical Technology, Vol. 7, pp257-262, published by Interscience Publishers, Inc. (1951) or US Pat. 1,922,459 and 3,010,076, the contents of which are incorporated by reference.The alkylene oxide (s) is generally polymerized at pressures above atmospheric pressure with an initiator in the presence of of an essentially basic chromium material an alkali metal hydroxide or tertiary amine which acts as a catalyst of a 1 c ox i 1 a c i or n. Suitable catalysts include strong bases, such as hydroxides, for example, potassium hydroxide and sodium hydroxide, etc. Suitable initiators include diols and low molecular weight polyols, for example, glycols, glycerol, trimethylolpropane, triethanolamine, penterterol 1, sorbitol and sucrose, and polyamines, for example, ethylene diamine, tolylene diamine, di ami nodi f in and polymethylene polyphenylene polyamines, and aminoalcohols, for example, ethanolamine and diethanolamine, and mixtures of these initiators. Other conventional polymeric polyols that can be added to the isocyanate-reactive composition include polyether polyols obtained from the condensation of appropriate proportions of glycols and polyols of higher functionality with dicarboxylic acids. Other conventional polymeric polyols that can be added to the isocyanate-reactive composition include p 1 i t i -o ethers, polyamides, polyesteramides, polycarbonates, polyacetals, polyolefins and polysiloxanes. These polymeric polyols are they are generally used in this art, and are prepared by conventional means. The polyamines mentioned above can have a molecular weight of at least 1000, and include amine terminated polyethers, polyethers, polyesteramides, polycarbonates, polyacetals, polyolefins and polysiloxanes. The polyamines may also have a molecular weight of less than 1000, and include aliphatic, cycloaliphatic or araliphatic polyamines containing two or more groups, such as low molecular weight amine terminated polyethers, and aromatic polyamines such as DETDA.The appropriate iminium or enamino functional reagents including derivative compounds of the modification of the amino functional compounds mentioned above, for example, by reacting them with an aldehyde or ketone. The aforementioned polyether polyols that can be used include hydroxyl-terminated reaction products of polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, 1,4-buta nd 1, neopentyl glycol, 1,6-hexanediol, cyclohexane dimethanol. , glycerol, trimethoprim, or polyether polyols, or mixtures of polyhydric alcohols, - and - polycarboxylic acids, particularly dicarboxylic acids or their ester-forming derivatives, for example, succinic acid, glutaric acid and adipic acid or their dimethyl esters, sebacic acid, italic anhydride, tetrachlorophthalic anhydride, or terephthalate Dimethyl, or its mixtures. It is also possible to use the polyethers obtained by the polymerization of lactones, for example, c ap r o 1 a c t a on s, together with a polyol or with hydroxy carboxylic acids, such as hydroxy caproic acid. Polyesteramides can be obtained by including aminoalcohols such as ethanolamine in mixtures of potassium and methacrylate. The polyether polyols that can be used include products obtained by condensing thiodiglycol alone or with other glycols, alkylene oxides, dicarboxylic acids, formaldehyde, amide no 1 coho 1, or ammonium or carboxylic acids. The polycarbonate polyols that can be used include products obtained by reacting diols, such as 1, 3-p r or ndi or 1, 1, 4 b u t a nd i or 1, 1,6-hexanediol, diethylene glycol, or glycol of t ee t rae fileno, with diaryl carbonates, for example, diphenyl carbonate, or with phosgene. The polyacetal polyols that can be used include those prepared by reacting glycols such as diethylene glycol, triethylene glycol or hexanediol with formaldehyde. Appropriate polyacetals can also be prepared by polymerizing cyclic acetals. Suitable polyolefin polyols include homo-and butadiene-terminated hydroxy copolymers, and suitable polysiloxane polyols include diols and triols of polydimethylsiloxane. Other conventional polymeric polyols which may also contain the isocyanate-reactive composition comprise dispersions or solutions of polymers of condensation or addition in polyols of the type mentioned above. These modified polyols, often referred to as "polymer polyols", have been described in the prior art, and include products obtained by insitu polymerization of one or more vinyl monomers, eg, styrene and / or acrylonitrile, in polyo ie polymeric, for example, polyols of po 1 i é t e r, or by the internal reaction between a polyisocyanate and an amino and / or hydroxy functional compound, such as triethanolamine, in a polymeric polyol. Polyoxyalkylene polyols containing between 5% and 50% by weight of the dispersed polymer are particularly useful. Particles of dispersed polymers smaller than 50 microns are preferred. The average molecular weight of these additional conventional polymeric polyols preferably ranges from 1000-8000, more preferably 1500-7D00; the hydroxyl value is 15-20, more preferably 20-100. The most preferred conventional polymeric polyols that can be added to the isocyanate-reactive mixture are po 1 and oxy 1 in po 1 and oxyprote 1 in polyols having an average molecular weight of 2000 to 7,000, a 1 to 3 or more. With an average nominal value of 2-3, and an oxyethylene content of 1020% by weight, the oxyethylene groups are preferably at the end of the polymer chain. The amount of these additional polymeric polyols (ie, polyol ethers) in the isocyanate-reactive composition is up to 50% by weight of said composition.

In the combination of the total polyol in the isocyanate-reactive composition, it is preferable that the ratio of diol / triol in the polymer polyols varies between 20/60 and 60/20, preferably between 30/50 and 50/30. the isocyanate-reactive composition is a chain extender agent.The chain extenders will be evident for ~ "~ _. _ __., experts in the art from the description of the invention. In general, useful chain extender agents are those having a formula weight of less than 750, preferably 62 to 75_0. Chain extender agents have at least two functional groups containing active hydrogen atoms, and include examples such as secondary and primary diamines, amino alcohols, amino acids, hydroxide acids, glycols, etc., and mixtures thereof. It is preferable that they have a functionality of two. Polyol chain extenders such as ethylene glycol, diethylene glycol, 1-b u t a nd i o 1, dipropylene glycol, and tripropylene glycol are selected.; aliphatic and aromatic amines, for example, 4, 4 '-me t i 1 in o dianilines with a minor alkyl substituent (C i - C6) if your each N-atom, etc. Other chain extenders include primary and secondary amines that react more readily with the polyisocyanates used in the invention than water. These include f in i 1 end i amine, ethylenediamine, diethylenetriamine, N- (2-hydroxypropyl) ethylenediamine, N, N'-di- (2-hydroxylpropyl) -ethylenediamine, piperazine, 2 me ti 1 pi pe razi na, etc. Compounds such as ethoxylated hydroquinone can also be used as a chain extender agent. In addition, fatty amines and ether amines can be used as chain extenders. Examples of ether amines include primary ether amines of the formula: ROCH2CH2CH2NH2, and ether diamines such as ROCH2CH2CH2NH CH2 CH2CH2 NH2, wherein R is an alkyl with 6-15 carbons, (both compounds available for sale in TOMAH PRODUCTS); and ethoxylated amines of formula: wherein Ri is an alkyl group with 10 to 26 carbon atoms, n is the total amount of moles of ethylene oxide and is 2-15, and x is 1 to 14 (available for sale in TOMAH PRODUCTS). Other ether amines include fatty amines based on tallow, such as sodium amines, tallow diamines, tallow triamines, tallow tetramines, hydrogenated tallow amine, tallow amine dioleate, etc. These tallow-based amines are also available for sale from TOMAH PRODUCTS The chain extenders mentioned above can be used individually, or combined or mixed with other chain extenders, including diethylene glycol, dipropylene glycol, ethanolamine, M-me ti 1 di et ano 1 amine, and N-eti 1 diet not 1 ami a, as well as aduct o_s obtained by the esterification of aliphatic carboxylic acids with aliphatic diols or triols, as the examples mentioned, with 0 , 01 to 1.08 mol of acid per mole of diol / triol The preferred chain extenders are 1,4-butanediol, 1,6-hexanedi or 1, neopentyl glycol, 1,4-cyclohexanediol, ethylene glycol, bishidr ox iet ox i be nc e no, glycerin of hydroquinone ethoxyiada, and diethylene glycol, alone or mixed.

The amount of chain extenders used will affect the physical properties of the surface polyurethane foam. Therefore, in this process, it is important to use the chain extender in the quantities specified in the invention. In general, by increasing the amount of chain extenders in the polyether system, a harder foam will be produced. Without intending to assert it, it is believed that the chain extender introduces hard segments in the elastomer. However, a significant increase in hardness generally results in a decrease in flexibility at low temperature and a reduction in fatigue resistance of the elastomer. Without intending to assert it, it is believed that the decrease in these physical properties is attributed to a decrease in the percentage of relatively long (soft) chain segments in the elastomer. There are other disadvantages if an excessive amount of chain extender is used; for example, the compatibility of the polyol in the isocyanate-reactive composition and the chain extender in the resin decreases with increasing short-chain extender, which causes significant processing problems and limitations to those systems. In addition, bulk charges and / or storage for even brief periods are not economically profitable due to the resulting phase separation of the polyol and the chain extender. Even in use, processing demands an appropriate mixture to prevent phase separation. An incompatibility of the system and / or a marginal mixture can adversely affect the physical properties of the final polyurethane foam products. As soon as the reactive materials move away from the balanced equilibrium between isocyanate and hydroxy ingredients, the resulting products, for example, shoe soles, will crack with wear, which makes these items unusable. trade . Although the amount of chain extender added to the isocyanate-reactive composition depends on the hardness condition, to avoid the above-mentioned problems, the inventor has found that the chain extender is preferably present in averaged amounts from 6.0% to about 12.5% by weight of the isocyanate reactive composition.

The expansion agent used in disagreement with the present invention is water. It is the only explosive agent in the present process. Water r e a c c io > na with isocyanate groups that generate nascent carbon dioxide which then originate the polymer that forms the reaction mass to expand and acquire a reduced density. For the purpose of this invention, water is present in effective amounts to result in polyurethane foam having the desired density as described herein. The amount of water used is based on the density requirement of the single shoe. Preferably, the water is present in the range of from about 0.25% to about 0.70% of the total weight of the isocyanate reactive composition and more preferably from about 0.5% to about 0.60% by weight of the total isocyanate reactive composition. The invention has found that the amount of water used is related to the amount of the chain extender present. More specifically, it has been found that when the weight ratio of the chain extender agent averaged from about 0.01 to about 0.20 and more preferably from about 0.02 to approximately 0.09, the polyurethane foams having the required characteristics are formed. This is a characteristic that makes the polyurethane foam of the present invention totally exclusive of other flexible foams since the foams are more flexible, this ratio is greater than 1 and usually greater than 10. Thus, in the flexible foams produced in In the prior art, the ratio is less than 5 times greater and usually an order of magnitude greater than the ratio used in the preparation of the reaction product of the present invention. The reaction system of the invention comprises surfactant in addition to conventionally used additives, such as flame retardants and catalysts, necessary for particular applications. Useful flame retardants include phosphonates, phosphites and phosphates, such as tris- (2-chlorosopropyl) phosphate (TCPP), dimethyl methyl phosphonate, ammonium polyphosphate, and various cyclic phosphates and phosphonate esters known in the art; halogen compounds known in the art, such as brominated diphenyl ether and other brominated aromatics; melanin; antimony oxides, such as antimony pentoxide and antimony trioxide; zinc compounds, such as zinc oxide; alumina trihydrate; and magnesium compounds, such as magnesium hydroxide. The flame retardants can be used in any appropriate amount that will be apparent to those skilled in the art. However, it is preferable that the flame retardant be used in an amount between 0 and 55% of the isocyanate-reactive component of the invention. The catalysts include tertiary amines, organometallic compounds and saturated or unsaturated C? 2- C24 fatty acid amides, and di, tri or t e t r a-a 1 canos having at least one catalytic amino group and at least one reactive amino group. Fatty amido-amines with hydroxyl substituents can also be used. A particularly preferred amido-amine compound is the product of the reaction N, N-dimethypropyl diamine, and a mixed fatty carboxylic acid available is BUSPERSE® 47 from Buckman Laboratories. Other preferred catalysts are triethylene diamine, bis- (2- (N, N-d ime tyl ami no) e t i 1) é t e r, and mixtures thereof. Other catalysts that can be used include amines, tertiary, and tertiary amine salts (eg, "delayed action catalysts"). The catalysts are used in quantities necessary for a particular application, which will be apparent to an expert in the art from the description of the invention. Other co-additive additives generally used in the art may also be used in the in v ~ etion. Examples of suitable additives include fillers, such as calcium carbonate, silica, mica, olastonite, wood dust, melamine, glass or mineral fibers, glass spheres, etc.; pigments, such as black carbon; surfactants; internal mold release agents; and plasticizers. These additives will be used in amounts that will be apparent to those skilled in the art from the description of the invention. Suitable surfactants include the various silicone surfactants, preferably those which are block copolymers of a polysiloxane and a polyalkylene. Examples of these surfactants are products DC-193 and Q4-3667, available from Dow Corning, and Tegostab B4113, available from Goldschmidt. Other suitable surfactants also include surfactants without silicon content, such as po 1 i (a 1 qui 1 enóxi do s). When a surfactant is used, the amount is preferably 0.1 to 2%, more preferably 0.2% to 1.3%, of the total weight of the isocyanate-reactive composition. Polyurethanes are formulated and modeled in objects modeled by casting methods conventionally known in the art, which generally comprise the use of a casting machine. Examples of low pressure casting machines include those sold by Klockner Ferromatik Desma, Inc., Erlander, Kentucky, including DS 30/30 and PSA 91, although high pressure models can also be used, including machines manufactured by Cannon Corp In the casting process, the polyisocyanate composition is referred to as the "A" component, and the isocyanate-reactive composition and water are referred to as the "B" component. If additives are used, they are usually incorporated in the "B" component, although they can also be added in the "A" component, as long as they do not react with isocyanate. The mixture of component "B", including additives, may be combined or stirred in an appropriate container or supply tank, generally at a temperature between 20 ° C and 50 ° C, although temperatures up to 75 ° C can be used. The mixture can be stirred with conventional propellant agitators (generally provided by the casting machine manufacturer) at RPM's of several hundred maximum. The components "A" and "B" are placed in separate containers, usually equipped with stirrers, of the casting machine where the temperature of each component varies between room temperature and 70 ° C. Modeled polyurethane products are manufactured by conducting each component through appropriate metering pumps to a mixing head where the components are mixed at low pressure, generally pressures less than 30 bar, preferably less than 20 bar. Then, the mixed components are poured or injected into a mold. Once an expected form of mold is filled, the mold is closed and vulcanized. Vulcanization temperatures vary between 30 ° C and 60 ° C. Vulcanization (as indicated by demold times) takes 1 to 30 minutes, usually between 3 and 10 minutes. This vulcanization time is sufficient to facilitate mixing, and foaming if necessary, and filling the mold, although it is quite fast to obtain high production rates. The reaction of component "A" and component "B" to manufacture the patterned polyurethanes is carried out at an isocyanate index between 0.85 and 1.15, preferably between 0.90 and 1.05. More preferably, the reaction is carried out at an isocyanate index between 0.95 and 1.0 when based on the total available active hydrogens, including the reaction of water. The polyurethane foams of the invention are not low density polyurethane foams. The product density varies between 0.1 and 1.1 spg, preferably between 0.25 and 0.80, and more preferably between 0.3 and 0.75 spg. Unlike the low density polyurethane foams, the polyurethane foams prepared according to the invention show excellent mechanical characteristics, including abrasion resistance, durability, stability and flexibility, which makes them ideal to be used as shoe soles. When using the invention to manufacture integral surface microcellular polyether elastomer articles, such as shoe soles, one aspect that is highly preferred, either of the two Commonly used sole manufacturing processes is satisfactory. In one process, the soles of the right and left feet are cast as unit soles, removed from the cast, and then glued to the upper parts of the footwear with an appropriate adhesive. In the other process, the upper parts of the footwear, that is, the right and left foot, are presented as a modeling surface, and the formulation is injected into the mold cavity defined by the upper parts of the shoe and the mold walls. . Anyways, the molds are closed-wall molds to obtain the shape of the mold's defined sole. This unique shape may not be smooth and may have mold edges incorporated, for example, for resilience, padding, anti-slip handles, etc. In any of the processes, conventional adhesives (also called "cements") for gluing (also called "cementing") the soles to the tops are well known. In the second process, ie direct fixation, the adhesive may be the casting polyurethane minus the vulcanized blowing agent with the casting foam while it is vulcanized, or it can be a different polyurethane adhesive. Unless otherwise indicated, all percentages are weight percentages. In addition, unless otherwise indicated, all weights are in grams. The following examples demonstrate the invention. In the examples, reference was made to the following formulations and components of the reaction: EXAMPLE 1 In this Example, a polyurethane foam was prepared by mixing the Suprasec® 2433 prepolymer with the isocyanate-reactive composition in the presence of water in a low pressure casting machine (DS 30/30 or PSA 91, both sold by Klockner Ferromatik Desma, Inc.), according to the procedure described in the invention. The quantities of each component used are indicated by weight in the following table: Specifically, Suprasec® 2433 was prepared by placing basically pure MDI (54.3 kg./lOO kg Suprasec® 2433), composed of 97.5% of 4,4'-MDI and 2.5% of 2,4 '. -MDI in a reaction vessel at 40 ° C. The temperature of the reaction vessel was raised to 80 ° C, and Daltocel ® F481 (39.7 kg./lOO kg of Suprasec® 2433) was added. The mixture was stirred at 80 ° C every 2 1/2 hours, and at that time it was determined that the NCO content of the mixture varied between 18.25-18.65%. Suprasec® 2020 (6 kg./lOO kg of Suprasec® 2433) was added to the reaction mixture at 80 ° C, and allowed to mix for 30 minutes. Then, the reaction mixture was allowed to cool to room temperature, and it was found that the final NCO content was between 18.90% and 19.3%. The contents were placed in the container of a low pressure casting machine, equipped with an agitator and a temperature control system, to control the temperature of the components between 5 ° C and 70 ° C.

Component B consisting of the isocyanate-reactive components and water, in the amounts mentioned above, was mixed at room temperature in a second container of the casting machine, equipped with a stirrer and a temperature control system, to control the temperature of the components between 5 ° C and 70 ° C. The modeled polyurethane product was formed by conducting each component, in the weight ratio indicated above, by pumps of the casting machine into the mixing head where the components are mixed at a low pressure, and the pressure is less than 20 bar . Then, the mixture of the two components was placed in the appropriate mold of model shoe A or model B (see Figures 1-2). Once the expected mold form was filled, the mold was closed, and the vulcanization took place at a vulcanization temperature of 30-60 ° for 3 to 10 minutes, and the shoe sole of Model A or B composed of foam was formed of polyurethane. The polyurethane foam was modeled on a shoe sole of model A or B (see Figures 1 - 2, respectively) with the corresponding shoe mold. The "Free Time" Model Mold from San Antonio Shoes Company was used to prepare a Footwear sole Model A, and the "Bounce" Model Mold from olverine World Wide Co. for the footwear sole model B. Figure 1 shows the footwear sole model A (1). The SAS in the lower half of the sole component (5) identifies it as the San Antonio Footwear Model. The shoe sole contains a design of indentations (2) in the upper half of the component, of the ... s u_e the (anterior part of the foot) and the lower half of the sole component. The thickness of the sole is relatively thin; It's 5/16 ''. There are several channels (3) both in the anterior part of the foot and in the lower sole. The depth of the notches is less than 1/16". These notches have rounded angles, and do not form a straight line. If a g rage occurs, it occurs in the indicated area (4). Figure 2 shows the sole of footwear model B (6). This model of footwear is quite different from the footwear model A. The anterior part of the foot (7) is relatively thick; its thickness is equal to 1/2"or more.The front part of the foot contains a design consisting of grooves that form notches (6), and the depth of these grooves is 3/32" thick. Unlike the notches in Model A, these notches form a straight line through the part anterior of the foot In addition, they form angles with a square shape, instead of the rounded angles of model A. Comparative Examples 1-3 Comparative Example 1 is a traditional formulation for preparing a polyurethane with polyether polyol having an OE content of less than 25% by weight. Comparative Examples 2 and 3 describe two formulations, in which only 1 type of polyether polyol of high OE content is used. In Comparative Example 2, only the high-OE polyether polyol was used in the absence of the random OE / OP copolymer, while in the Comparative Example 3, the random OE / OP copolymer was used, but in the absence of the polyether polyol with high content of ethylene oxide. The various formulations were prepared according to the procedure described in Example 1, in which Suprasec® 2433 was mixed with the polyether polyol in a casting machine, and then modeled in the corresponding shoe model. The formulations in Comparative Examples 1-3 are indicated in the following table. Formulation for Comparative Examples 1-3 Example 2 This example compares the flexural fatigue of the shoe sole prepared from the polyurethane foam of Example 1 and the comparative examples.

The polyurethane foam produced in Example 1 and comparative examples 1-3 was compared by a standard test known as the Bata Belt Flex test, described in the "Physical Test Methoo", published by the SATRA Footwear Technology Center, February 1989, pp. 1-9, whose content is incorporated herein by way of reference. The sample is placed in a band bending machine, manufactured by Satra Footwear Technology Center, North Kettering - Hamptonshire, England, which subjects the anterior part of the sole to a bending tension. In this way, this test measures the capacity of the shoe sole, prepared from 1 polyurethane foam, to withstand cracks as a result of millions of flexion cycles to which each shoe sole is subjected. The relationship of the results of Bata Belt Flex and the risk of fatigue cracks is indicated in the following Table 1: TABLE I The results of the Bata Belt Flex test in the various shoe soles produced from the polyurethane foam in Example 1 and the Comparative Examples are indicated in Table II below. As indicated by the data in the table, for the soles composed of the polyurethane prepared in Comparative Examples 1-3, the values of Bata Belt Flex were significantly lower than those of the soles prepared from the polyurethane foam prepared according to the invention. (ie, Example 1). These results indicate that there is a remarkable and important improvement in the properties of Bata Belt Flex when the footwear sole of the polyurethane of the invention was prepared. The data precisely reflects that the combination of the two polyether polyols with high content of ethylene oxide in the isocyanate-reactive component causes an inertgic effect. The performance of bending fatigue of the polyurethane produced when both polyols were present was significantly improved, that is, shoe soles became much more flexible, compared to shoe soles composed of a polyurethane foam prepared from the isocyanate composition. containing a polyol (Comparative Examples _2 and 3) or none (Example Comparative 1). The embodiments and preferred examples mentioned above contribute to illustrate the scope and principles of the invention. These embodiments and these examples will reveal other embodiments and examples to those skilled in the art. These other embodiments and examples are within the scope of the invention. Therefore, the invention will be limited only by the rei indications attached.

Claims (45)

1. A flexible integral surface polyurethane foam, prepared by contacting, under effective reaction conditions, a polyisocyanate composition with an isocyanate-reactive composition, in the presence of water as a blowing agent, characterized in that: a) the polyisocyanate composition has a free NCO value between 15% and 25%, and contains an isocyanate-terminated prepolymer, prepared from the reaction of an excess of an organic polyisocyanate and a first polymer polyol protected by ethylene oxide having a nominal hydroxyl functionality average of 2-6, an equivalent weight between about 700 and about 5000, and an ethylene oxide content of at least about 25% by weight, therefore, at least 50% of the ethylene oxide group is present at the end of the polyether polyol, b) the isocyanate-reactive composition contains a chain extender in an amount between about 6.0% and approximately 12.5% by weight, and a mixture of second polyether polyol protected by ethylene oxide and a random copolymer of ethylene oxide and propylene oxide in substantial amounts effective to form said polyurethane foam; the polyethylene oxide-protected second polyol has an average nominal hydroxyl functionality of 2-3, an equivalent weight between about 700 and about 5000, and an ethylene oxide content of at least 25% by weight of the mixture, and at least about 50% of the ethylene oxide group is at the end of the polyether polyol; and the copolymer has an average nominal hydroxyl functionality of 2-3, an equivalent weight between about 700 and about 5000, and an ethylene oxide content of at least about 60% by weight; and c) water, as the sole blowing agent, in an amount effective to give the resulting polyurethane at a density ranging from about 0.1 to about 1.1 specific gravity, in which the weight ratio of the water to the agent Chain extender varies between about 0.01 and about 0.20.

2. The polyurethane foam of Claim 1, characterized in that the isocyanate-reactive composition contains a diol and a triol, and the diol / triol weight ratio ranges from about 1: 3 to about 3: 1,

3. The polyurethane foam of Claim 1, characterized in that the amount of the second polyol protected by ethylene oxide in said mixture is between about 20% and about 80% by weight of the isocyanate-reactive composition, and the amount of existing copolymer is between about 1, 5 and about 23% by weight of the isocyanate-reactive composition.

4. The polyurethane foam of Claim 3, characterized in that the amount of the second polyether polyol protected by ethylene oxide is between about 40% and about 60% by weight of the isocyanate-reactive composition.

5. The polyurethane foam of Claim 3, characterized by the amount of The copolymer varies between 2% and 5% by weight of the isocyanate-reactive composition.

6. The polyurethane foam of Claim 1, characterized in that the ethylene oxide content of the second polyol protected by ethylene oxide varies between about 25% - and about 35% by weight of the composition, and the ethylene oxide content of the copolymer it varies between about 60% and about 85% by weight of the composition.

7. The polyurethane foam of the Claim 1, characterized in that the equivalent weight of the second polyol protected by ethylene oxide varies between about 1000 and about 3000.

8. The polyurethane foam of Claim 7, characterized in that the equivalent weight of the second polyol protected by oxide of the wood varies between about 1200 and about 2000.

9. The polyurethane foam of the Rei indication 1, characterized in that the equivalent weight of the copolymer varies between about 1000 and about 3000.

10. The polyurethane foam of Claim 9, characterized in that the equivalent weight of the copolymer varies between about 1200 and about 2000.

11. The polyurethane foam of Claim 1, characterized in that the amount of water varies between about 0.25% and about 0.70% by weight of the isocyanate-reactive composition.

12. The polyurethane foam of claim 1, characterized in that the weight ratio of the water to the chain extender varies between about 0.02 and about 0.09. _

13. The polyurethane foam of the Rei indication 1, characterized by its density it varies between about 0.25 and about 0.80 of specific gravity.

14. The polyurethane foam of Claim 13, characterized in that its density varies between 0.30 and 0.75 of specific gravity.

15. The polyurethane foam of the Rei indication 1, characterized in that the polyisocyanate composition is reacted with the isocyanate-reactive composition in a weight ratio of about 0.4 to about 2.5.

16. The polyurethane foam of the Claim 1, characterized in that the isocyanate composition has a free NCO value between about 17% and about 21%, the first polyether polyol _ has an average nominal hydroxyl functionality of 24, an equivalent weight of about 1000 to about 3000, and has an ethylene oxide content between about 25% and about 35% by weight of the composition, and the organic polyisocyanate used to prepare the Prepolymer is a polyisocyanate base of diphenylmethane diisocyanate.

17. The polyurethane foam of Claim 16, characterized in that the prepolymer is prepared from the reaction of an excess amount of polyisocyanate based on phenylmethane diisocyanate and the polyol, wherein the diphenylmethane diisocyanate contains from about 5% to about 15% by weight of a variant of MDI, greater than 85% by weight of 4,4'-MDI and less than 5% by weight of 2,4'-MDI,

18. The polyurethane foam of claim 16, characterized in that the polyisocyanate based on phenylmethane diisocyanate contains at least 85% by weight of 4,4 '.MDI or a variant thereof.

19. The polyurethane foam of the Claim 1, characterized in that at least about 90% of the groups in the prepolymer formed by reacting the polyisocyanate and the polyol are urethane groups.

20. A process for preparing a flexible polyurethane foam, characterized in that it comprises contacting, under effective reaction conditions, a polyisocyanate composition with an isocyanate-reactive composition, in the presence of water as the sole blowing agent, and in said process: ) the polyisocyanate composition has a free NCO value between about 15% and about 25%, and contains an isocyanate-terminated prepolymer, prepared from the reaction of an excess of an organic polyisocyanate and a first polymer polyol protected by ethylene oxide having an average nominal hydroxyl functionality of 2-6, an equivalent weight between about 700 and about 5000, and an ethylene oxide content of at least approximately 25% by weight, and at least about 50% of the oxide group of The enzyme is at the end of the polyether polyol; b) the isocyanate-reactive composition contains a chain extender agent in an amount between about 7.0% and about 12.5% by weight, and an effective amount of a mixture of a second polyether polyol protected by ethylene oxide and a random copolymer of ethylene oxide and propylene oxide to form said polyurethane foam; the second polyethylene oxide protected polyol has a nominal hydroxyl functionality average of 2-3, an equivalent weight between about 700 and about 5000, and an ethylene oxide content of at least about 25% by weight of the mixture, at least about 50% of the ethylene oxide group is at the end of the polyether polyol; and the copolymer has an average nominal hydroxyl functionality of 2-3, an equivalent weight between about 700 and about 5000, and an ethylene oxide content of at least 60% by weight; and c) water, as the sole blowing agent, in an amount effective to give the resulting polyurethane at a density ranging from about 0.1 to about 1.1 specific gravity, in which the weight ratio of the water to the agent Extender of cana varies between approximately 0.01 and approximately 0.20.

21. The process of Claim 20, characterized in that the isocyanate-reactive composition contains a diol and a triol, and the diol / triol weight ratio ranges from about 1: 3 to about 3: 1.

22. The process of Claim 20, characterized in that the amount of the second polyol protected by ethylene oxide in said mixture is between about 20% and about 80% by weight of the isocyanate-reactive composition, and the amount of existing copolymer is between about 1. , 5% and approximately 23% by weight.

23. The process of Claim 22, characterized in that the amount of polyol varies between 40% and 60% by weight of the isocyanate-reactive composition.

24. The process of Claim 22, characterized in that the amount of copolymer varies between about 2% and about 5% by weight of the isocyanate-reactive composition.

25. The process of Claim 20, characterized in that the ethylene oxide content of the second polyol protected by ethylene oxide ranges between about 25% and about 35% by weight of the composition, and the ethylene oxide content of the copolymer ranges from about 60% and approximately 85% by weight of the composition.

26. The process of the Rei indication 20, characterized in that the equivalent weight of the second polyol protected by ethylene oxide varies between about 1000 and about 3000.

27. The process of Claim 26, characterized in that the equivalent weight of the second polyol protected by ethylene oxide varies between approximately 1200 and approximately 2000.

28. The process of Claim 20, characterized in that the equivalent weight of the copolymer ranges from about 1000 to about 3000.

29. The process of Claim 28, characterized in that the equivalent weight of the copolymer varies between about 1200 and about 2000.

30. The process of Claim 20, characterized in that the amount of water varies between about 0.25% and about 0.70% by weight of the composition reactive to the isocyanate.

31. The process of the Rei indication 20, characterized in that the weight ratio of the water to the chain extender varies from approximately 0.02 to approximately 0.09.

32. The process of Claim 20, characterized in that its density varies between about 0.25 and about 0.80 of specific gravity.

33. The process of Claim 32, characterized in that its density varies between approximately 0.30 and approximately 0.75 of specific gravity.

34. The process of Claim 20, characterized in that the polyisocyanate composition is reacted with the isocyanate-reactive composition in a weight ratio of from about 0.3 to about 3.0.

35. The process of Claim 20, characterized in that the isocyanate composition has a free NCO value between about 17% and about 21%, the first polyether polyol has an average nominal hydroxyl functionality of 24, an equivalent weight of about 1000 to about 3000 , and has an ethylene oxide content between about 25% and about 35% by weight of the composition, and the organic polyisocyanate used to prepare the prepolymer is a polyisocyanate based on diphenylmethane diisocyanate.

36. The process of Claim 35, characterized in that the prepolymer is prepared from an excess amount of polyisocyanate based on phenylmethane diisocyanate and polyol, and the di-phenyl diisocyanate contains from about 5% to about 15% by weight of a variant of MDI, greater than about 85% by weight of 4,4 '-MDI and less than about 5% by weight of 2, 4' -MDI

37. The process of the Rei indication 35, characterized in that the polyisocyanate based on phenylmethane diisocyanate contains at least 85% by weight of 4,4 '.MDI or a variant thereof.

38. The process of Claim 20, characterized in that at least about 90% of the groups in the prepolymer formed in making the polyisocyanate and the polyol are reactive groups.

39. A reaction system, characterized in that: a) The polyisocyanate composition has an isocyanate-terminated prepolymer, prepared by reacting an excess of an organic polyisocyanate and a first polymer polyol protected by xylene or ethylene having a hydroxyl functionality rated average of 2-6, an equivalent weight between approximately 700 and approximately 5000, and an oxide content of ethylene of at least about 25% by weight, therefore, at least 50% of the ethylene oxide group is at the polyether polyol end; b) The composition reactive to the isocyanate c or n t i in a chain extender agent in an amount between about 6.0% and about 12.5% by weight, and a mixture of a second polyether polyol protected by oxide of. ethylene and a random copolymer of ethylene oxide and propylene oxide; and the second polyethylene oxide-protected polyol has an average nominal hydroxyl functionality of 2-3, an equivalent weight between about 700 and about 5000, and an ethylene content of at least about 25% by weight. of the mixture, and at least about 50% of the ethylene oxide group is at the polyether polyol end, and the copolymer has an average nominal hydroxyl functionality of 2-3, an equivalent weight between about 700 and about 5000. , and an ethylene oxide content of at least 60% by weight, and c) Water, and in said system the free NCO value of the isocyanate composition varies between 15% and 25%, and the weight ratio of the water with he Chain extender agent varies between about 0.01 and about 0.20

40. The reaction system of Claim 39, characterized in that the weight ratio of the polyisocyanate composition and the isocyanate-reactive composition ranges from about 0.4 to about 2.5.

41. The reaction system of the Rei indication 39, characterized in that the weight ratio of the water with the chain extender varies between about 0.02 and about 0.09.

42. The reaction system of the Claim 39, characterized in that the polyisocyanate composition has an NCO value between about 17% and about 21%.

43. The reaction system of Claim 39, characterized in that the polyisocyanate composition has an NCO value between about 17% and about 31%, the first polyether polyol having a functionality average nominal hydroxyl of 2-4, an equivalent weight of about 1000 to about 3000, and has an ethylene oxide content between about 25% by weight of the composition, and the organic polyisocyanate used to prepare the prepolymer is a polyisocyanate based on diphenylmethane diisocyanate.

44. The reaction system of the Claim 43, characterized in that the diphenylmethane diisocyanate contains from about 5% to about 15% by weight of an MDI variant, greater than about 85% by weight of 4,4'-MDI and less than about 5% by weight of 2, 4 '-MDI.

45. The reaction system of the Claim 43, characterized in that the polyisocyanate based on phenylmethane diisocyanate contains at least 85% by weight of 4,4'-MDI or a variant thereof.