MXPA97002991A - Polyol mixtures of three components to use will seize rigi polyurethane foams - Google Patents

Abstract

A rigid closed cell foam based on polyisocyanate manufactured by reacting an organic isocyanate with a polyol composition in the presence of a blowing agent is now provided, wherein the polyol composition contains at least: a) a polyether polyol of polyoxyalkylene starting with an aromatic amine having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more b) a polyoxyalkylene polyether polyol initiated with the aliphatic amine having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more, and c) an aromatic polyester polyol having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more. The blowing agent is selected from the group consisting of cyclopentane, HFC, HCFC and mixtures thereof in an amount of 5.0 weight percent or more, in the weight of the polyol composition. Preferably, the blowing agent is soluble in the polyol composition without sacrificing and advantageously improving the thermal insulation and the dimensional stability of the resulting polyurethane foam. Also disclosed is a storage stable polyol composition and methods for producing a rigid closed cell foam based on polyisocyanate

Description

"POLYOL MIXTURES OF THREE COMPONENTS TO BE USED TO INSULATE RIGID POLYURETHANE FOAMS" This is a continuation in part of the US Patent Applications Serial Numbers 08 / 551,507; 08 / 551,658 and 08 / 548,362, each one of which was presented. November 1995 and are incorporated herein by reference. 1. FIELD OF THE INVENTION This invention relates to rigid closed cell polyurethane foams with a variety of blowing agents. More specifically, the invention relates to the use of a polyol composition wherein a variety of blowing agents and preferably soluble agents are useful. The polyol composition is composed of at least one polyoxyalkylene polyether polyol initiated with aromatic amine, a polyoxyalkylene polyether polyol initiated with aliphatic amine and an aromatic polyester polyol. 2. BACKGROUND OF THE INVENTION Various blowing agents, including hydrocarbons among others, are often only partially soluble if not completely insoluble in many polyols used to make rigid polyurethane foams. It is believed that this is due to the non-polar hydrophobic characteristic of the hydrocarbons. The insolubility or poor shelf life of hydrocarbon-polyol blends to date has restricted the storage of mixed batches of the polyol-hydrocarbon-based blowing agent to be used for a later time. Due to the efficient solubility of the various hydrocarbon blowing agents in polyols, they must be added to the polyols under constant stirring and immediately before distributing the foaming ingredients through a mixing head. The insolubility of the various hydrocarbon-based blowing agents also tend to lead to larger, thicker or uneven cell structures in a polyurethane foam. As is well known, the thermal conductivity of a foam generally increases to a poor cell structure, Therefore, it has been critical that the blowing agent (s) employed be uniformly dispersed under constant stirring through the mixture of Polyol immediately before foam deformation in order to obtain a rigid polyurethane foam having the desired thermal insulation values. In US Pat. No. 5,391,317, Smits seeks to make a foam that has both good dimensional stability and thermal insulation using hydrocarbons as the blowing agents. This reference disclosed the use of a specific blend of alicyclic alkane blowing agents of 5 and 6 carbon atoms, isopentane and n-pentane in specific molar percentages in combination with a polyol mixture consisting of an aromatic polyether initiated polyol. , an aromatic polyester polyol, a polyether polyol initiated with a different amine. As the aromatic initiated polyether polyol, Smits suggested using an alkylene oxide duct of a phenol-formaldehyde resin. The specific mixture of the aliphatic and isomeric aliphatic blowing and alkane agents is disclosed by Smits as producing a foam having thermal insulation values. The problem of obtaining a closed cell rigid polyurethane foam that has both good dimensional stability and thermal insulation at low densities was also discussed in "An Insight Into of Characteristics of a Nucleation Catalyst in HCFC-Free Rigid Foam Systems" by Yoshimura and others . This publication disclosed the results of the evaluations on a catalyst guest used in a normal polyurethane formulation to test the effects of each catalyst on thermal insulation and dimensional stability of the foam. The authors observed that the solubility of the cyclopentane in a polyol composition was reduced by increasing the mixing ratio of the aromatic amine-based polyols. Furthermore, not only the authors observed that the solubility of cyclopentane in the polyols was reduced as the content of polyether polyol initiated with aliphatic amine was reduced and the polyether polyol initiated with aromatic amine was increased, but they also observed that observed no significant effect on thermal conductivity when it was increased in polyether polyol content initiated with aromatic amine. 3. SUMMARY OF THE INVENTION It would be highly desirable to provide a polyol composition to produce a dimensionally stable rigid closed cell polyurethane foam such as a polyol composition having good thermal insulation properties. Therefore, a stable polyol composition during storage comprising a blowing agent and a polyol composition containing at least: a) a polyoxyalkylene polyether polyol initiated with aromatic amine having a hydroxyl number is now provided. of 200 milliequivalents of polyol / gram of KOH or more; b) a polyoxyalkylene polyether polyol initiated with aliphatic amine having a hydroxyl number of 200 milliequivalents of polyol / gram of KOH or more; and c) an aromatic polyester polyol having a hydroxyl number of 200 milliequivalents of polyol / gram of KOH or more. The blowing agent (s) used with the polyol composition is selected from the group consisting of cyclopentane, HFC and HCFC generally with the amount of the blowing agent present, being at least about 5.0 weight percent based on the weight of the polyol composition. In addition, the amount of the aromatic polyester polyol is 18.0 weight percent or less, based on the weight of the polyol composition. The blowing agent (s) preferably soluble in the polyols used in the polyol composition. The blowing agents employed, and in particular the HFCs and HCFCs when used in association with the polyol compositions of the present invention, have also been found to offer faster demolding times for the resulting foams. In addition, the resulting foams typically have lower densities, improved K-factors, improved thermal insulation properties and improved dimensional stabilities relative to the foams produced using other polyol systems. A rigid closed cell foam based on polyisocyanate is also provided which is made by reacting an organic isocyanate with a polyol composition in the presence of a blowing agent, wherein the polyol composition contains at least: a) a polyol of polyoxyalkylene polyether initiated with aromatic amine having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more; b) a polyoxyalkylene polyether polyol initiated with an aliphatic amine having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more; c) an aromatic polyester polyol having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more, in an amount of 18.0 weight percent or less, based on the weight of the polyol composition. Again, the blowing agent is selected from the group consisting of cyclopentane, HFC and HCFC and is present in an amount of at least about 5.0 weight percent based on the total weight of the polyol composition. By using these constituents in the polyol composition, the blowing agent is generally soluble in the polyol composition. A polyurethane foam is also provided wherein the polyol composition contains at least one of the blowing agents mentioned above. The polyol composition will preferably solubilize the blowing agent in the polyol composition without sacrificing and advantageously improving the thermal insulation and dimensional stability of the resulting polyurethane foam. Contrary to what was stated by Yoshimoto and others, it was surprising to discover that the polyether polyol initiated with aromatic amine used in the invention has an impact on the thermal insulation of the foam. A method is also provided for producing a rigid closed cell foam based on polyisocyanate by reacting an organic isocyanate with a polyol composition wherein a blowing agent present in an amount was introduced (and preferably dissolved instead of emulsified). of at least 5.0 weight percent or more, based on the weight of the polyol composition and further containing at least: a) a polyoxyalkylene polyether polyol initiated with aromatic amine having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more; b) a polyoxyalkylene polyether polyol initiated with aliphatic amine having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more; and c) an aromatic polyester polyol having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more, in an amount of 18.0 weight percent or less, based on the weight of the polyol composition.

DETAILED DESCRIPTION OF THE INVENTION A storage-stable polyol composition is provided consisting of at least one blowing agent which is selected from the group consisting of cyclopentane, HFC and HCFC, and the polyol composition described herein. A polyol composition is considered "storage stable" or "soluble", when the polyol composition has the ability to retain the blowing agent in solution or in a dissolved state for a period of at least 5 days. The determination of whether or not the blowing agent is in solution or dissolved is measured by mixing the blowing agent with the ingredients of the polyol composition in a crystalline glass bottle, by covering the bottle and allowing the content to remain at rest for 5 hours. days at room temperature without agitation. If during the visual inspection there is no phase separation in such a way that two discrete layers are formed, the blowing agent is considered soluble in the polyol composition, and the polyol composition is considered as being stable during storage. This test that lasts for at least five (5) days is only for measuring purposes if a formulation of the specific polyol composition is suitable for solubilizing the blowing agent. As will be discussed further below, the blowing agent may be added to the polyol composition weeks before foaming, seconds before foaming or immediately in the mixing head. The scope of the invention includes each of these modalities. By stating that the blowing agent is soluble in the polyol composition, it is meant that the polyol composition employed must be capable of solubilizing the blowing agent and that it is either limited to a specific point in the process where the blowing agent is solubilized and not for a period of time such as five days used for purposes of measuring the ability of the polyol composition to dissolve the blowing agent. When it is said that the polyol composition "contains" a blowing agent or that the blowing agent is "dissolved in" or "in solution" with the polyol composition, this includes those embodiments wherein the blowing agent is mixed with the other ingredients of the polyol composition for a period of time sufficient to dissolve the blowing agent in the polyol exposure before introducing the polyol composition into the mixing head for reaction with an organic isocyanate compound, which would not include those embodiments wherein the blowing agent is supplied in a regulated manner with a separate stream towards the distributor head to react with an organic isocyanate. However, this does not mean that the blowing agent can not be supplied in a regulated manner with a separate stream to react with an organic isocyanate in order to form the desired product.

The polyol composition contains polyols consisting of at least the above-mentioned polyols a), b) and c). Other ingredients that can be included in the polyol composition are other polyols, catalysts, surfactants, blowing agents, fillers or fillers, stabilizers and other additives. As used in this specification and in the claims, the term "polyol (s)" includes polyols having hydroxyl, thiol and / or amine functionalities. The term "polyol (s)" as used herein, however, is limited to compounds that contain at least certain polyester or polyoxylakylene groups and have a number average molecular weight of 200 or more. When the word "polio (is)" is used together with and to modify the words polyether, polyester or polyoxyalkylene polyether, the word "polyol" then has the meaning of defining a functional polyhydroxy polyether. Both polyols a) and b) are polyoxyalkylene polyether polyols. These polyols can generally be prepared by polymerizing the alkylene oxides with the polyhydric amines. Any suitable alkylene oxide can be used, such as ethylene oxide, propylene oxide, butylene oxide, amylene oxide and mixtures of these oxides. The polyoxyalkylene polyether polyols can be prepared from other starting materials, such as tetrahydrofuran and alkylene oxide-tetrahydrofuran mixtures.. ; epihalohydrins such as epichlorohydrin; as well as the aralkylene oxides, such as styrene oxide. Included among the polyether polyols are polyoxyalkylene polyols, polyoxypropylene polyols, polyoxybutylene polyols, polytetramethylene polyols and block copolymers, for example, combinations of poly-1,2-oxybutylene, and polyoxyethylene polyoxypropylene and polyoxyethylene polyols, poly-1,4-tetramethylene and polyoxyethylene polyols, and copolymer polyols prepared from mixtures or sequential addition of two or more alkylene oxides. The polyoxyalkylene polyether polyols can be prepared by a known process, such as, for example, the process disclosed by Wurtz in 1859 and Encyclopedia of Chemical Technology, Volume 7, pages 257-262, published by Interscience Publishers, Inc. ( 1951) or in the US Patent Number 1,922,459. The alkylene oxides may be added to the initiator individually in sequence one after the other to form blocks, or in a mixture to form a heterether polyether. The polyoxyalkylene polyether polyols which may have either primary or secondary hydroxyl groups. It is preferred that at least one of the polyols initiated with the amine of higher preference both polyols a) and b) are polyether polyols terminated with a secondary hydroxyl group through the addition of, for example, propylene oxide in the terminal block . It is preferred that one or both of the polyols initiated with amine a) and b) contain 50 percent by weight or more, and up to 100 percent by weight of alkylene oxides forming the secondary hydroxyl group, such as the polyoxypropylene groups , based on the weight of all the oxyalkylene groups. This amount can be measured by adding 50 weight percent or more of the alkylene oxides which form the secondary hydroxyl group to the initiator molecule, during the manufacture of the polyol. The appropriate starter molecules for compounds a) and b) are the primary or secondary amines. These would include for the polyether polyol initiated with aromatic amine a), aromatic amines such as aniline, N-alkylphenylene diamines, 2,4'-, 2,2'- and 4,4'-ethylenedianiline, 2,6- or 2,4-toluenediamine, vicinal toluenediamines, o-chloroaniline, p-aminoaniline, 1,5-diaminonaphthalene, methylenedianiline, the different condensation products of aniline and formaldehyde, and isomeric diaminotoluenes giving preference to the vicinal toluenediamines.

For the polyol b) initiated with aliphatic amine, any aliphatic amine, whether branched or unbranched, substituted or unsubstituted, saturated or unsaturated, can be used. These would include as examples the mono-, di- and tri-alkanolamines, such as monoethanolamine, methylamine, triisopropanolamine; polyamines such as ethylene diamine, propylene diamine, diethylenetriamine; or 1,3-diaminopropane, 1,3-diaminobutane and 1,4-diaminobutane. Preferably, the aliphatic amines include any of the diamines and triamines more preferably the diamines. In at least one embodiment of the present invention, each of the polyols a) and b) have number average molecular weights of 200 to 750 and nominal functionalities of 3 or more. By means of a nominal functionality, it is meant that the expected functionality is based on the functionality of the initiator molecule instead of the actual functionality of the final polyether after manufacture. The polyol c) is an aromatic polyester polyol. Suitable polyester polyols include those suitable polyester polyols which are obtained, for example, from polycarboxylic acids and polyhydric alcohols. An appropriate polycarboxylic acid can be used such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pyrrhoic acid, suberic acid, azelaic acid, sebasic acid, brasilic acid, tapsic acid, maleic acid, fumaric acid, glutaconic acid , α-hydromuconic acid, β-hydromuconic acid, α-butyl-α-ethyl-glutaric acid, α, β-diethyl-succinic acid, isophthalic acid, terephthalic acid, phthalic acid, hemimelitic acid and 1,4-cyclohexanedicarboxylic acid. An appropriate polyhydric alcohol such as ethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1,2-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, hydroquinone, resorcinol glycerol, glycerin, 1, can be used. 1, 1-trimethylolpropane, 1,1,1, -trimethylolethane, pentaerythritol, 1,2,6-hexanetriol, a-methyl glucoside, sucrose and sorbitol. Also included within the term "polyhydric alcohol" are compounds of the phenol grade, such as 2,2-bis (4-hydroxyphenyl) -propane, commonly known as Bisphenol A. The hydroxyl-containing polyester can also be a polyester amide as obtained by including certain amine or amino alcohol in the reagents for the preparation of the polyesters. In this way, polyester amides can be obtained by condensing an aminoalcohol, such as ethanolamine with the polycarboxylic acids noted above or can be produced using the same components that make up the hydroxyl-containing polyester with only a portion of the components being a diamine. , such as ethylenediamine. A preferred aromatic polyester polyol useful in accordance with the teachings of the present invention is a polyester polyol initiated with alpha-methylglucoside derived from polyethylene terephthalate. This polyol has a molecular weight of about 358, a hydroxyl number of about 360 milliequivalents of polyol per gram of KOH and a nominal average functionality of 2.3. As mentioned above, each of the polyols a), b) and c) have hydroxyl numbers of 200 or more milliequivalents of polyol per gram of KOH. In hydroxyl numbers of less than 200, the dimensional stability of the foam begins to deteriorate. The optimum nominal functionality of each polyol initiated with amine appears to be 4 or more with hydroxyl numbers of 400 or more. Also, the optimum nominal functionality of the aromatic polyester polyol appears to be 2 or more, with average hydroxyl numbers of 350 or more. The total amount of the aromatic polyester polyol c) is 18.0 weight percent or less and more preferably 15.0 weight percent or less based on the total weight of all the ingredients of the polyol composition. Therefore, even though the scale of polyols a) and b) can vary widely (ie, from about 20.0 percent to 80.0 percent by weight of the polyol composition), under a preferred embodiment, the weight ratio of polyol a) initiated with aromatic amine to polyol b) initiated with aliphatic amine will be between about 0.8: 1.0 to 1.2: 1. Therefore, the weight ratio of either the polyol a) or b) to the aromatic polyester polyol c) is about 3: 1 or greater. The scope of the invention broadly includes a polyol composition containing the polyols a), b) and c) combined together in a mixture by separately making the polyether polyols and the polyester polyol and subsequently combining the resulting polyols together in a mixture. Optionally, polyols a) and b) can be prepared by the co-initiation method, wherein the aromatic amine and the aliphatic amine initiators are first mixed together after which the alkylene oxide (s) are added and made react in the starter mix; with the polyol (c) being combined later. The last method is the preferred method. In the latter method, the amount of the polyether polyol initiated with aliphatic amine in the polyol composition would be calculated based on the percentage of the aliphatic initiator in the initiator mixture multiplied by the percentage of polyether polyol (resulting from the addition of the alkylene oxide to the initiator mixture) in the polyol composition. Other polyols in addition to the polyols a), b) and c), described herein, can and preferably are added to the polyol composition. These would include polythioether polyols, polyester amines and polyacetals containing hydroxyl groups, aliphatic polycarbonates containing hydroxyl groups, polyoxyalkylene polyethers terminated with amine, polyester polyols, other polyoxyalkylene polyether polyols and graft dispersion polyols. In addition, mixtures of at least two of the aforementioned polyols can be used. The preferred additional polyols are polyoxyalkylene polyether polyols and / or polyester polyols, however, the total amount of the polyester polyols used (including any of the polyester polyols in addition to the polyol c)) will preferably not exceed 18.0 by percent by weight, based on the total weight of the polyol composition. Additional polyoxyalkylene polyether polyols in addition to polyols a) and b) include those initiated with polyhydroxyl compounds. Examples of these initiators are trimethylolpropane, glycerin, sucrose, sorbitol, propylene glycol, dipropylene glycol, pentaerythritol and 2,2-bis (4-hydroxyphenyl) -propane and mixtures thereof. Preferred polyols are initiated with polyhydroxyl compounds having at least 4 sites reactive with alkylene oxides, and furthermore they can be oxyalkylated only with propylene oxide. In an especially preferred embodiment, the additional polyol is a polyoxyalkylene polyether polyol having a nominal functionality of 5 or more, which can be initiated with a polyhydroxyl compound. The high functionality serves to increase the crosslink density in order to provide a dimensionally stable foam. Suitable polyhydric polythioethers which can be condensed with alkylene oxides include the condensation product of thiodiglycol or the reaction product of a dicarboxylic acid as disclosed above for the preparation of the hydroxyl-containing polyesters with any other polyol of appropriate thioether. Polyhydroxyl-containing phosphorus compounds that can be used include those compounds disclosed in US Patent Number 3,639,542. Preferred polyhydroxyl-containing phosphorus compounds are prepared from alkylene oxides and phosphorus acids having an equivalence of P2O5 from about 72 percent to about 95 percent. Suitable polyacetals that can be agreed with alkylene oxides include the reaction products of formaldehyde or other suitable aldehyde with a dihydric alcohol or an alkylene oxide, such as those disclosed above. Suitable aliphatic thiols which can be condensed with alkylene oxides include alkanethiols containing at least two -SH groups, such as 1,2-ethanedithiol, 1,2-propanedithiol, 1,2-propanedithiol and 1,6-hexanediol; alkene thiols such as 2-butan-1, 4-dithiol; and alkene thiols such as 3-hexen-1, 6-dithiol. Also suitable are polymer-modified polyols, in particular so-called graft polyols. Graft polyols are well known in the art and are prepared by in situ polymerization of one or more vinyl monomers, preferably acrylonitrile and styrene, in the presence of a polyether polyol, particularly polyols containing a small amount of unsaturation natural or induced. Methods for preparing these graft polyols can be found in columns 1 to 5 and in the Examples of US Pat. No. 3,652,639; in columns 1 to 6 and the Examples of the North American Patent Number 3,823,201; particularly in columns 2 to 8 and in the Examples of the North American Patent Number 4,690,956; and in U.S. Patent Number 4,524,157; all of which patents are incorporated herein by reference. Polyols modified with non-grafted polymer are also suitable, for example, as those prepared by the action of a polyisocyanate with an alkanolamine in the presence of a polyether polyol, as disclosed in US Pat. Nos. 4,293,470; 4,296,213 and 4,374,209; dispersions of polyisocyanurates containing suspended urea groups as disclosed by U.S. Patent Number 4,386,167; and polyisocyanurate dispersions also containing biuret linkages, as disclosed by U.S. Patent Number 4,359,541. Other polymer modified polyols can be prepared by reducing the in situ size of polymers until the particle size is less than 20 millimeters, preferably less than 10 millimeters. The average hydroxyl number of the polyols a), b) and c) in the polyol composition should be 200 milliequivalents of polyol per gram of KOH or more and, more preferably, 350 milliequivalents of polyol per gram of KOH or more . Individual polyols that fall below the lower limit can be used, but the average must fall within this scale. Polyol compositions whose polyols are on average within this scale produce good dimesionally stable foams. In calculating whether the average hydroxyl number falls within this scale, only those polyols having a number average molecular weight of 200 or more are taken into account by definition. The amount of additional polyols relative to polyols a), b) and c) is not intended to be limited as long as the desired object of manufacture of a dimensionally stable foam has good thermal insulation values and optionally, but preferably can be achieved. the solubilization of the blowing agent (s) in the polyol composition. In this regard it is believed that the aforementioned objects can be achieved using 50 weight percent or less of the combined weight of the polyols a), b) and e), based on the weight of all the polyols. In addition to the above, the invention also includes using at least one blowing agent which is selected from the group consisting of cyclopentane, HFC, HCFC and mixtures thereof. The blowing agents can be added and solubilized in the polyol composition for storage and subsequent use, in a foaming apparatus or they can be added to a tank premixed in the foam forming apparatus and preferably they are solubilized in the polyol composition. immediately before pumping or supply in a regulated manner the foaming ingredients to the mixing head. Alternatively, the blowing agent can be added to the foaming ingredients and the mixing head as a separate stream even though the complete solubility could be limited due to the short amount of time in which the blowing agent is exposed to the composition of polyol in the mixing head. The advantage of the polyol composition of the invention is that the polyol composition provides the flexibility of storage-stable polyol compositions containing the desired blowing agent, or the solubilization of the blowing agent with the polyol composition in the tank. pre-mix, or however, for a short period of time add it to the mixing head to make a foam of the desired quality. We have found that the polyol composition of the invention is specially adapted to allow a variety of blowing agents to be employed including blowing agents that are selected from the group consisting of cyclopentane, HFC, HCFC and mixtures thereof in order to produce rigid closed cell polyisocyanate based foams filling the desired objects. The amount of the blowing agent is 5.0 weight percent or more, based on the weight of the polyol composition. The specific amount of the blowing agent (s) will depend largely on the desired density of the foam product. For most applications, the polyurethane free lift densities for thermal insulation applications range from free elevation densities of 1.42 to 28.3 cubic centimeters, preferably from 3.40 to 7.08 cubic centimeters. The preferred total densities of the foams packed up to 10 weight percent, implying the weight percentage of the foam ingredients above the theoretical amount necessary to fill the mold volume during foaming, are 3.40 to 7.08 cubic centimeters and more preferred from 3.68 to 5.66 cubic centimeters. The amount by weight of all blowing agents is generally based on the polyol composition from about 5.0 weight percent to 40.0 weight percent and more preferably from 7.0 percent to 36.0 weight percent. Suitable hydrofluorocarbons, perfluorinated hydrocarbons and fluorinated ethers (to which reference is made herein as HFCs) that are useful in accordance with the teachings of the present invention include difluoromethane (HFC-32); 1,1,1,2-tetrafluoroethane (HFC-134a); 1, 1, 2, 2-tetrafluoroethane (HFC-134); 1,1-difluoroethane (HFC-152a); 1,2-difluoroethane (HFC-142); trifluoromethane, heptafluoropropane; 1,1,1-trifluoroethane; 1, 1, 2-trifluoroethane; 1,1,1,2,2-pentafluoropropane; 1, 1, 1, 3, 3-pentafluoropropane (HFC 245fa); 1,1,1,1-tetrafluoropronene; 1,1,2,3,3-pentafluoropropane; 1,1,1,3,3-pentafluoro-n-butane; 1,1, 1,2, 3, 3, 3-heptafluoropropane (HFC 227ea); hexafluorocyclopropane (C-216); octafluorocyclobutane (C-318); perfluorotetrahydrofuran; perfluoroalkyl tetrahydrofurans; perfluorofuran; perfluoro-propane; -butane, -cyclobutane, -pentane, -cyclopentane and -hexane, -cydohexane, -heptane, and -octane; perfluorodiethyl ether, perfluorodipropyl ether; and perfluoroethylpropyl ether. HFCs 134a and HFC 236ea, respectively, are preferred among the HFC blowing agents. Suitable hydrochlorofluorocarbon blowing agents that can be used in accordance with the teachings of the present invention are l-chloro-1,2-difluoroethane; l-chloro-2, 2-difluoroethane (142a); 1-chloro-1,1-difluoroethane (142b); 1,1-dichloro-1-fluoroethane (141b); 1-chloro-l, 1,2-trifluoroethane; 1-chloro-1,2,2-trifluoroethane; 1,1-diochloro-1,2-difluoroethane; 1-chloro-1,1,2-tetrafluoroethane (124a); 1-chloro-1,2,2,2-tetrafluoroethane (124); 1,1-dichloro-1,2,2-trifluoroethane; 1, 1-dichloro-2,2,2-trifluoroethane (123); and 1,2-dichloro-1,2,2-trifluoroethane (123a); monochlorodifluoromethane (HCFC-22); l-chloro-2,2,2,2-trifluoroethane (HCFC-133a); gem-chlorofluoroethylene (R-1131a); chlorheptafluoropropane (HCFC-217); Chlorodifluoroethylene (HCFC-1122); and trans-chlorofluoroethylene (HCFC-1131). The most preferred hydrochlorofluorocarbon blowing agent is 1,1-dichloro-1-fluoroethane (HCFC-141b). Blowing agents that can be used in addition to the blowing agents selected from the group consisting of cyclopentane, HFC, HCFC and mixtures thereof can be divided into chemically active blowing agents that chemically react with the isocyanate or with the other ingredients of the formulation for releasing a gas for foaming, and physically active blowing agents that are gaseous at exothermic foaming temperatures or less without the need to chemically react with the ingredients of the foam to provide a blowing gas. Those gases that are thermally unstable and decompose at elevated temperatures are included within the meaning of physically active blowing agents.

Examples of chemically active blowing agents are preferably those which react with the isocyanate to release the gas, such as CO2 • Suitable chemically active blowing agents include but are not limited to water, mono- and polycarboxylic acids having a molecular weight of 46 to 300, salts of these acids and tertiary alcohols. Water is preferably used as a blowing agent. The water reacts with the organic isocyanate to release the CO2 gas, which is the effective blowing agent. However, since the water consumes isocyanate groups, an equivalent molar excess of isocyanate must be used to replenish the isocyanates consumed. Water is typically found in small amounts in the polyols as a by-product and may be sufficient to provide the desired blowing of a chemically active substance. Preferably, however, the water is further introduced into the polyol composition in amounts of 0.02 percent to 5 percent by weight, preferably, from 0.5 percent to 3 percent by weight based on the weight of the composition of polyol. The organic carboxylic acids used are advantageously aliphatic mono- and polycarboxylic acids, e.g., dicarboxylic acids. However, other organic mono- and polycarboxylic acids are also suitable. The organic carboxylic acids, if desired, may also contain substituents which are inert under the reaction conditions of the polyisocyanate polyaddition or are reactive with the isocyanate and / or may contain olefinically unsaturated groups. Specific examples of chemically inert substituents are halogen atoms, such as fluorine and / or chlorine, and alkyl, e.g., methyl or ethyl. The substituted organic carboxylic acids contain at least one additional group which is reactive for the isocyanates, e.g., a mercapto group, a primary and / or secondary amino group, preferably a primary and / or secondary hydroxyl group. The appropriate carboxylic acids, therefore, are substituted or unsubstituted monocarboxylic acids, e.g., formic acid, acetic acid, propionic acid, 2-chloropropionic acid, 3-chloropropionic acid, 2,2-dichloropropionic acid, acid hexanoic, 2-ethylhexanoic acid, cyclohexane carboxylic acid, dodecanoic acid, palmitic acid, stearic acid, oleic acid, 3-mercapto-propionic acid, glycolic acid, 3-hydroxypropionic acid, lactic acid, ricinoleic acid, 2- aminopropionic, benzoic acid, 4-methylbenzoic acid, salicylic acid and anthranilic acid and the unsubstituted or substituted polycarboxylic acids, preferably dicarboxylic acids, e.g. oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, glutaric acid, adipic acid, sebacic acid, dodecanoic acid, tartaric acid, phthalic acid, isophthalic acid and citric acid. Preferred acids are formic acid, propionic acid, acetic acid and 2-ethylhexanoic acid, preferably formic acid. Amino salts are usually formed using tertiary amines, e.g., triethylamine, dimethylbenzylamine, diethylbenzylamine, triethylenediamine or hydrazine. The tertiary amine salts of formic acid can be used as chemically active bulking agents that will react with the organic isocyanate. The salts can be added as such or formed in situ by reaction between any tertiary amine (catalyst or polyol) and formic acid contained in the polyol composition. The combinations of any of the aforementioned chemically active bulking agents can be employed, such as formic acid, formic acid salts and / or water. The physically active swelling agents are those that boil at an exothermic or lower foam-forming temperature, preferably at 50 ° C or less. Particularly preferred physically active swelling agents are those that have an ozone suppression potential of 0.05 or less. Examples of physically active swelling agents are volatile non-halogenated hydrocarbons having from 2 to 7 carbon atoms, such as alkanes, alkenes, cycloalkanes having up to 6 carbon atoms, alkyl ethers, cilokyalkylene ethers and ketones; and the decomposition products. Examples of the volatile non-halogenated hydrocarbons include linear or branched alkanes, e.g., butane, isobutane, 2,3-dimethylbutane, n- and isopentane and mixtures of pentane of technical grade, n- and iso-hexanes, n- and iso-heptanes, n- and iso-octanes, n- and iso-nonanes, n- and iso-decans, n- and iso-undecanes, and n- and iso-dodecanes. The n-pentane, isopentane or n-hexane or a mixture thereof is preferably used as additional swelling agents. In addition, the specific examples of alkenes are 1-pentene, 2-methylbutene, 3-methylbutene and 1-hexene, cycloalkanes in addition to cyclopentane, are cyclobutane or cyclohexane, specific examples of linear or cyclic ethers are dimethyl ether, ether of diethyl, methylethyl ether, vinylmethyl ether, vinylethyl ether, divinyl ether, tetrahydrofuran and furan, and the specific examples of ketone are acetone, methylethyl ketone and cyclopentanone. Pure or technical grade cyclopentanone can be used, the latter containing about 70 weight percent cyclopentane with the remainder including 2,3-dimethylbutane, pentane and isopentane. Mixtures of cyclopentane, pentane and isopentane as described in U.S. Patent No. 5,391,317 are also included and are incorporated herein by reference. Physically active decomposing-type swelling agents that release a gas through thermal decomposition include walnut flour, amine / carbon dioxide complexes and alkyl alkanoate compounds, especially methyl and ethyl formates. The catalysts can be used, which greatly accelerate the reaction of the compounds containing hydroxyl groups and with the modified or unmodified polyisocyanates. Examples of suitable compounds are the curing catalysts which also function to cut the tack time, activate the untreated strength and prevent shrinkage of the foam. Suitable catalysts for curing are organometallic catalysts, preferably organotin catalysts, although it is possible to use metals, for example, lead, titanium, copper, mercury, cobalt, nickel, iron, vanadium, antimony and manganese. The appropriate organometallic catalysts that are exemplified here by tin as the metal, are represented by the formula: RnSn [XR! -Y] 2, wherein R is an alkyl or aryl group of 1 to 8 carbon atoms, R - * - is a methylene group of 0 to 18 carbon atoms optionally substituted or branched with an alkyl group of 1 to 4 carbon atoms, Y is hydrogen or a hydroxyl group, preferably hydrogen, X is methylene, an -S-, an -SR2COO-, -SOOC-, an- O3S- or a group -OOC-, wherein R2 is alkyl of 1 to 4 carbon atoms, n is 0 or 2, provided that R ^ is Cn only when X is a methylene group. The specific examples are tin acetate (II), tin (II) octanoate, tin ethylhexanoate (II) and tin laurate (II); and the dialkyl salts (1-8C) tin (IV) of the organic carboxylic acids having from 1 to 32 carbon atoms, preferably from 1 to 20 carbon atoms, e.g., diethyltin diacetate, dibutyltin diacetate, dibutyltin diacetate , dibutyltin dilaurate, dibutyltin maleate, dihexyltin diacetate, dioctyltin diacetate. Other suitable organotin catalysts are the organotin alkoxides and the mono- or poly-alky (l-8C) tin (IV) salts of the inorganic compounds such as butyltin trichloride, dimethyl- and diethyl- and dibutyl- and dioctyl- and diphenyltin, dibutyltin dibuthoxide, di (2-ethylhexyl) tin oxide, dibutyltin dichloride, dioctyltin dioxide. However, tin catalysts with tin-sulfur bonds which are resistant to hydrolysis, such as dialkyl (1-20C) tin mercaptides, including dimethyl-, dibutyl- and dioctyltin dimercaptides, are preferred. Tertiary amines also activate the formation of the urethane linkage and include triethylamine, 3-methoxypropyl dimethylamine, triethylene diamine, tributylamine, dimethylbenzylamine, N-methyl-, N-ethyl- and N-cyclohexylmorpholine, N, N, N ', N', - tetramethylethylenediamine, N, N, N ', N', -tetramethylbutanediamine or -hexaniamine, propylene-diamine of N, N, N'-trimethylisopropyl, pentamethyldiethylenetriamine, tetramethyldiaminoethyl ether, bis (dimethylaminopropyl) urea, dimethylpiperazine, l-methyl-4-dimethylaminoethylpiperazine , 1,2-dimethylimidazole, 1-azabicyclo [3.3.0] octane and preferably 1,4-diazabicyclo [2.2.2] octane and the alkanolamine compounds, such as triethanolamine, triisopropanolamine, and N-methyl-N- ethyldiethanolamine and dimethylethanolamine. To prepare the polyisocyanurate (PIR) and the foams of PUR-PIR by the process according to the invention, a polyisocyanurate catalyst is employed. Suitable polyisocyanurate catalysts are alkali metal salts, for example, sodium salts, preferably potassium salts and ammonium salts, of organic carboxylic acids having 1 to 8 carbon atoms, preferably 1 or 2 carbon atoms , for example, the salts of formic acid, acetic acid, propionic acid or octanoic acid and corresponding tris (dialkylaminoethyl) -, tris (dimethylaminopropyl) -, tris (di-ethylaminobutyl) - and tris (diethylaminoalkyl) -s-hexahydrotriazines. However, (trimethyl-2-hydroxypropyl) ammonium formate, (trimethyl-2-hydroxypropyl) ammonium octanoate, potassium acetate, potassium formate and tris (dimethylaminopropyl) -s-hexahydrotriazine are polyisocyanurate catalysts which are They use usually. The appropriate polyisocyanurate catalyst is generally used in an amount of 1 to 10 parts by weight, preferably 1.5 to 8 parts by weight, based on 100 parts by weight of the total amount of polyols. Urethane-containing foams can be prepared with or without the use of chain and / or cross-linking agents which are not necessary in this invention to achieve the desired mechanical hardness and dimensional stability. The chain extenders and / or crosslinking agents used have a number average molecular weight of minus 400, preferably from 60 to 300; or if the chain lengthening agents have polyoxyalkylene groups then they have a number average molecular weight of less than 200. Examples are dialkylene glycols, and aliphatic, cycloaliphatic and / or araliphatic diols having from 2 to 14 carbon atoms, preferably, from 4 to 10 carbon atoms, e.g., ethylene glycol, 1,3-propanediol, 1, 10-decanediol, o-, m- and p-dihydroxychlorohexane, diethylene glycol, dipropylene glycol and preferably, 1, 4- butanediol, 1,6-hexanediol, bis (2-hydroxyethyl) hydroquinone, triols such as 1,2,4- and 1,3,5-trihydrocyclohexane, glycerol and trimethylolpropane. Polyurethane foams can also be prepared using secondary aromatic diamines, primary aromatic diamines, diaminodiphenylmethanes, 3, 3 '-di- and / or 3,3 * -, 5, 5'-tetraalkyl-substituted as chain aligners or crosslinking agents instead of or mixed with the diols and / or trioles mentioned above. The amount of the chain elongation agent, the crosslinking agent or a mixture thereof used, if used, is 2 percent to 20 weight percent, preferably 1 percent to 15 percent by weight based on in the weight of the polyol composition. However, as mentioned above, it is preferred that no chain / crosslinking elongation agent be used for the preparation of the rigid foams, since the polyether polyols described above are sufficient to provide the mechanical properties desired. If desired, the auxiliaries and / or additives can be incorporated into the reaction mixture for the production of cellular plastics by the polyisocyanate polyaddition process. Specific examples are surfactants, foam stabilizers, cell regulators, fillers or fillers, colorants, pigments, fire retardant agents, hydrolysis protection agents and fungistatic and bacterostatic substances. Examples of suitable surfactants are compounds that serve to support the homogenization of the starting materials and also regulate the cell structure of the plastics. Specific examples are salts of sulphonic acid eg, alkali metal salts or ammonium salts of dodecylbenzene or dinaphthylmethane-disulfonic acid, and ricinoleic acid; foam stabilizers, such as siloxane-oxyalkylene copolymers and other organopolysiloxanes, oxyethylated alkylphenols, oxyethylated fatty alcohols, paraffin oils, castor oil esters, ricinoleic acid esters, turkey red oil and ground walnut oil and cell regulators , such as paraffins, fatty alcohols and dimethylpolysiloxanes. Surfactants are usually used in amounts of 0.01 to 5 parts by weight based on 100 parts by weight of polyol component. For the purposes of the invention, the filler or filler materials are conventional organic and inorganic fillers or fillers and reinforcing agents. Specific examples are inorganic fillers or fillers, such as silicate minerals, for example, phyllosilicates, such as antiborite, serpentine, hornblende, amphibole, chrysotile and talc; metal oxides, for example, kaolin, aluminum oxides, titanium oxides and iron oxides; metal salts, for example, clay, barite and inorganic pigments, such as cadmium sulfide, zinc sulphide and glass, inter alia; kaolin (china clay), aluminum silicate and the coprecipitates of barium sulfate and aluminum sulfate, and natural and synthetic fibrous minerals such as ollastonite, metal and glass fibers of various lengths. Examples of suitable organic fillers or fillers are carbon black, melamine, rosin, cyclopentadienyl resins, cellulose fibers, polyamide fibers, polyacrylonitrile fibers, polyurethane fibers and polyester fibers based on the esters of the aromatic dicarboxylic acid. and / or aliphatic and in particular carbon fibers.

The inorganic and organic fillers or fillers can be used individually or in admixture and can be introduced into the polyol composition or isocyanate side in amounts of 0.5 percent to 40 percent by weight based on the weight of the components (the polyol composition and isocyanate, but the content of mats, non-woven materials and fabrics that are made of natural and synthetic fibers can reach values up to 80 weight percent Examples of suitable flame retardants are tricresyl phosphate, tris (2-chloroethyl) phosphate, tris (2-chloropropyl) phosphate and tris (2,3-dibromopropyl) phosphate In addition to the halogen-substituted phosphates mentioned above, it is also possible to use inorganic or organic flame retardants, such as red phosphorus, aluminum oxide hydrate, antimony trioxide, arsenic oxide, ammonium polyphosphate (Exolit®) and calcium sulfate, grafit derivatives or expandable cyanuric acid, e.g., melamine or mixtures of two or more of the flame retardant agents eg, ammonium and melamine polyphosphates and, if desired, corn starch or ammonium polyphosphate, melamine, expandable graphite and / or if aromatic polyesters are desired in order to provide non-combustibility to the polyisocyanate polyaddition products. In general, from 2 to 50 parts by weight, preferably from 5 to 25 parts by weight, of the flame retardant agents per 100 parts by weight of the polyol composition can be used. Additional details about the other conventional auxiliaries and additives mentioned above can be obtained from the specialist literature, for example, from the monograph by J.H. Saunders and K.C. Frisch, High Polymers, Volume XVI, Polyurethanes, Parts 1 and 2, Interscience Publishers, 1962 and 1964, respectively, or Kunststoff-Handbuch, Polyurethane, Volume VII, Carl-Hanser-Verlag, Munich Vienna, First and Second Editions, 1966 and 1983. Suitable organic polyisocyanates defined as having two or more isocyanate functionalities are conventional aliphatic, cycloaliphatic, araliphatic and preferably aromatic isocyanates. Specific examples include: alkylene diisocyanates with from 4 to 12 carbon atoms in the alkylene radical, such as 1,1-dodecane diisocyanate, 2-ethyl-1,4-tetramethylene diisocyanate, 2-methyl-diisocyanate 1, 5-pentamethylene, 1,4-tetramethylene diisocyanate and preferably 1,6-hexamethylene diisocyanate; cycloaliphatic diisocyanates such as 1,3- and 1,4-cyclohexane diisocyanate as well as any of the mixtures of these isomers, 1-isocyanato-3, 3, 5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate), diisocyanate 2 , 4- and 2,6-hexahydrotoluene as well as the corresponding isomeric mixtures, 4,4'-, 2,2'- and 2,4'-dicyclohexylmethane diisocyanate as well as the corresponding isomeric mixtures and preferably aromatic diisocyanates and polyisocyanates such as 2,4- and 2,6-toluene diisocyanate and the corresponding isomeric mixtures, 4,4'-, 2,4'- and 2, 2'-diphenylmethane diisocyanate and the corresponding isomer mixtures, mixtures of diisocyanates of , 4'-, 2,4'- and 2, 2-diphenylmethane and polyphenylenepolymethylene polyisocyanates (crude MDI), as well as mixtures of MDI and toluene diisocyanates. The organic polyisocyanates and diisocyanates can be used individually or in the form of mixtures. Particularly preferred for the production of rigid foams is the raw MDI containing from about 50 percent to 70 weight percent polyphenyl polymethylene polyisocyanate and from 30 percent to 50 weight percent diphenylmethane diisocyanate based on weight of all the polyisocyanates used. Frequently, the so-called modified multivalent isocyanates, that is, the products obtained by the partial chemical reaction of the organic diisocyanates and / or polyisocyanates are used. Examples include diisocyanates and / or polyisocyanates containing ester groups, urea groups, biuret group, allophanate groups, carbodiimide groups, isocyanurate groups and / or urethane groups. Specific examples include organic polyisocyanates, preferably aromatic, containing urethane groups and having an NCO content of 33.6 percent to 15 percent by weight, preferably 31 percent to 21 percent by weight based on total weight, e.g., with diols, triols, dialkylene glycols, trialkylene glycols or polyalkylene glycols of low molecular weight with a molecular weight up to 6000; the modified 4,4'-diphenylmethane diisocyanate or the 2,4- and 2,6-toluene diisocyanate, wherein examples of the di- and polyoxyalkylene glycols which can be used individually as mixtures include diethylene glycol, dipropylene glycol, polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethylene glycol, polyoxypropylene glycol and polyoxypropylene polyoxyethylene glycols or triols. The prepolymers containing NCO groups with an NCO content of 29 percent to 3.5 percent by weight, preferably 21 percent to 14 percent by weight based on the total weight and which are produced from the polyester polyols and / or preferably polyester polyols described below; 4,4'-diphenylmethane diisocyanate, mixtures of 2,4'- and 4,4'-diphenylmethane diisocyanate, 2,4- and / or 2,6-toluene diisocyanates or polymeric MDI are also suitable. In addition, liquid polyisocyanates containing carbodiimide groups having an NCO content of 33.6 percent to 15 percent by weight, preferably 31 percent to 21 percent by weight based on total weight have also proved appropriate, e.g., based on the diisocyanate of 4,4'- and 2,4'- and / or 2, 2'-diphenylmethane, and / or 2,4'- and / or 2,6-toluene diisocyanate. The optionally modified polyisocyanates can be mixed together or mixed with unmodified organic polyisocyanates such as 2,4'- and 4,4'-diphenylmethane diisocyanate, polymeric MDI, 2,4'- and / or 2,6-toluene. The organic isocyanates used in the invention preferably have an average functionality greater than 2, more preferably 2.5 or more. This provides higher crosslink density in the resulting foam, which improves the dimensional stability of the foam. To produce the rigid closed cell polyurethane foams of the present invention, the organic polyisocyanate and the isocyanate-reactive compounds are reacted in amounts such that the isocyanate index is defined as the number of equivalents of the NCO groups divided by the total number of equivalents of the hydrogen atom reactive to the isocyanate multiplied by 100 ranges from 80 to less than 150, preferably from 90 to 110. The polyol composition of the invention provides the flexibility of a large processing window since the solubility of the polyol composition and the dimensional stability of thermal insulation of the resulting foam are not affected essentially through the wide scale of isocyanate rates. If the rigid foams contain, at least in part, bound isocyanate groups, an isocyanate index of 150 to 6000, preferably 200 to 800, is generally used. In a method of the invention, there is provided the reaction of an organic isocyanate with a polyol composition containing at least: a) a polyoxyalkylene polyether polyol initiated with aromatic amine having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more; b) a polyoxylalkylene polyether polyol initiated with aliphatic amine having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more, in an amount of 10 weight percent or less, based on the weight of the composition of polyol; c) an aromatic polyester polyol having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more, in an amount of 18.0 weight percent or less, based on the weight of the polyol composition; and d) a swelling agent that is selected from the group consisting of cyclopentane, HFC and HCFC. Optionally, but preferably, the hydrocarbon-based swelling agent is dissolved in the polyol composition. In one embodiment, the polyol composition contains the swelling agent in solution before reacting with the organic isocyanate. Preferably the organic isocyanate and the polyol composition are reacted at isocyanate rates ranging from 80 to 115. Through this scale, the K factors of the foam are essentially constant and the foams are dimensionally stable. An essentially constant K-value means that the variety of values is + 10 percent or less between the lowest and highest values within the scale. Through the scale, the foam also remains dimensionally stable as will be defined below. The measurements for the K factor are taken from core samples, as will be described below in the definition of a dimensionally stable foam and are the initial K factors. Rigid foams made of polyisocyanate polyaddition products are advantageously produced by a one-step process, for example using reaction injection molded parts or a low pressure high pressure method, in an open or closed mold, for example in a metal mold, or in a pouring application at the site where the surfaces containing the reaction mixture become part of the finished article. The starting components can be mixed at a temperature of 15 ° C to 90 ° C, preferably 20 ° C to 35 ° C and introduced into the open or closed mold, if desired under superatmospheric pressure. The mixing of the isocyanate with the polyol composition containing the dissolved swelling agent can be carried out mechanically by means of an agitator or a stirring screw or under high pressure by the shock injection method. The temperature of the mold is from 20 ° C to 110 ° C, preferably from 30 ° C to 60 ° C and in particular from 45 ° C to 50 ° C. The rigid foams produced by the process in accordance with the invention and the corresponding structural foams are used, for example, in the vehicle industry - automotive, aircraft, boat building - and in the furniture and sports industries. They are particularly suitable in the construction and refrigeration sectors as thermal insulators, for example, as intermediate layers for a laminated board or refrigerators with foam filling, freezer housings, field day coolers. For on-site casting applications, the rigid foam can be emptied or injected to form a sandwich structure of a first substrate / foam / second substrate or can be laminated over a substrate to form a substrate foam structure. The first and second substrates can each be manufactured independently of the same material or of different materials, depending on the final use. Suitable substrate materials comprise metal, for example aluminum, tin or rolled metal formed such as that used in the case of refrigeration cabinets; wood, including composite wood, a triblock of acrylonitrile-butadiene-styrene rubber (ABS), optionally modified with a diblock of styrene-butadiene, triblock of styrene-ethylene / butylene-styrene, optionally functionalized with maleic anhydride and / or maleic acid , polyethylene terephthalate, polycarbonate, polyacetals, polystyrene with high impact resistance modified with rubber (HIPS), mixtures of HIPS with polyphenylene oxide, copolymers of ethylene and vinyl acetate, ethylene and acrylic acid, ethylene and vinyl alcohol, homopolymers or copolymers of ethylene and propylene such as polypropylene, high density polyethylene, high molecular weight high density polyethylene, polyvinyl chloride, nylons 66 or amorphous thermoplastic polyesters. The preferred ones are aluminum, tin, ABS, HIPS, polyethylene and high density polyethylene. The polyurethane foam can be adjoined to the internal surfaces of the first and second substrates, or the polyurethane foam can be contiguous with a layer or sheet of the synthetic material interposed between the substrates. In this way, the sequence of layers in the composite product may also consist of a first substrate / polyurethane foam / layer, or a sheet / second substrate or first substrate / layer or sheet / polyurethane foam / layer or sheet / second substrate . The layer or sheet of layers further interposed in the composite may comprise any of the aforementioned synthetic resins having good elongation, such as low density polyethylene or linear low density polyethylene in a stress relief layer or an activating material the adhesion between the polyurethane foam and the first and / or second substrates of choice. When a synthetic plastic material such as polyurethane having few or no binding or adhesion sites is selected as the first and / or the second substrate as an alternative for an adhesion activating layer, it is useful to first modify the surface of the substrate with a corona discharge or with a flame treatment to improve adhesion to polyurethane foam. During the operation of placing the foam in place, the substrates are set apart in spaced relation to define a cavity between the first substrate and the second substrate, and optionally the internal surface of at least one substrate preferably both are treated to activate the adhesion. This cavity is then filled with a liquid polyurethane system which reacts and forms foams in situ, ligating to the internal surfaces of the first and second substrates. In the case of a refrigeration unit or a freezing container, such as a package for field days, a thermoformed inert linear material is inserted into the outer hull of the freezer or the refrigeration cabinet, in separate fitted relationship to define a cavity , whose cavity is then filled with a foamed polyurethane foam on the site. In many cases it is only the polyurethane foam that holds together the outer shell and the inner lining, avoiding the need for dimensional stability of the foam. The polyurethane cellular products of the invention are rigid, implying that the ratio of the tensile strength to the compressive strength is high in the order of 0.5: 1 or greater and that they have less than 10 percent elongation. The foams are also closed-cell, implying that the number of open cells is 20 percent or less, or on the contrary, the number of closed cells is 80 percent or greater, the measurement being taken from a molded or packed foam. at 10 percent above the theoretical amount required to fill the mold with foam. The rigid polyurethane cell products are dimensionally stable exhibiting little or no shrinkage even at free expansion densities of 2.0 pcf or less. In a preferred embodiment, the rigid polyurethane cell products of the invention tested in accordance with the D 2126-87 method of the American Society for the Testing of Materials using core samples of densities of 2.0 pcf or less, with dimensions of 7.62 centimeters X 7.62 centimeters X 2.54 centimeters and they are taken from a box packed at 10 percent that measures 10.16 centimeters X 25.40 centimeters X 25.40 centimeters which advantageously has the following dimensional changes at 28 days of exposure: at 38 ° C / 100 percent relative unit, it is say, relative unit, no more than + 5 percent, more preferred no more + 3 percent; at 70 ° C / relative unit of 100 percent no more than + 5 percent, more preferably less than + 4 percent; at 70 ° C, dry at no more than t 8 percent, preferably no more than + 6 percent; at 93 ° C dry in no more than + 5, preferably not more than + 3 percent; and at -29 ° C after 7 days of exposure no more than + 5 percent, preferably no more than + 3 percent. The thermal insulation values of the rigid closed cell foams according to the preferred embodiments of the invention are 0.198 centimeter calorie / hour x square centimeter x ° C or less initial, more preferably, 0.186 or less initial, which is measured from the core in a sample overpacked to 10 percent. It has been found that foams made with the combination of polyether polyols initiated with aliphatic and aromatic amine as well as aromatic polyester polyols exhibited relatively low k-factors. Furthermore, it has been found that the swelling agent is only hardly soluble in polyol compositions employing more than about 18.0 weight percent of an aromatic polyester polyol constituent. In a preferred embodiment, rigid polyurethane foams are also advantageously not reliable on their surface despite their low density and the presence of polyols having a high hydroxyl number and a low equivalent weight. These foams typically exhibit a surface friability of less than 5 percent when tested in accordance with the C 421 method of the American Society for the Testing of Materials at core densities of 2.0 pcf or less, even at core densities of 1.5 pcf or less. The low surface friability allows the foam to adhere well to substrates. The term "polyisocyanate-based foam" as used herein, is meant to include polyurethane-polyurea, polyurethane-polyisocyanurate, polyurethane and polyisocyanurate foams.

WORK EXAMPLES Polyol A is a polyoxypropylene polyether polyol co-initiated with sucrose-dipropylene glycol having a nominal OH number of about 397.

Polyol B is a polyoxyethylene-polyoxypropylene polyether polyol co-initiated with approximately 90 percent toluene diamine of about 10 percent ethylenediamine based on the weight of the initiators, the polyol being terminated with about 68 weight percent of groups of oxypropylene based on the weight of all oxyalkylene groups and having a nominal OH number of about 500. Polyol C is an aromatic polyester polyol initiated with alpha-methylglucoside having a nominal OH number of about 360. POLYCAT® 5 is a pentamethyl-diethylenetriamine, a catalyst used in the preparation of rigid foams which can be obtained commercially from Air Products. DMCHA is dimethylcyclohexylamine which can be obtained commercially from BASF Corporation. UL-1 is a dibutyltin dimercaptide that can be obtained from Air Products. ISO A is polymethylene / polyphenylene polyisocyanate having a free NCO content of 31.8 percent and a functionality of about 2.7.

EXAMPLE 1 The amounts of 45.0 parts by weight of Polyol A, 40.0 parts by weight of Polyol B, 15.0 parts by weight of Polyol C. 0.9 part by weight of POLICAT 5, 0.8 part by weight of DMCHA, 0.1 part by weight of UL -1 and between 2.0 and 2.5 parts by weight of water depending on the swallowing agent used, were mixed together. Then, a different swelling agent was added as indicated in Table 1 under constant mixing, to the respective polyol compositions. Each polyol composition including the different swelling agents was mixed in a steel tank with a capacity of 7,750 liters and fixed to an Edge-Sweets® high pressure shock mixer. Variable amounts of ISO A were added to the different polyol compositions in the isocyanate tank were mixed by shock. The parameters for the Edge-Sweets® high pressure shock mixing machine were calibrated to determine the consistency and the resulting foams were allowed to expand freely as indicated in Table 1 for between 7 and 28 days.

Table 1 SAMPLE 1 2 3 4 Polyol A 45 45 45 45 Polyol B 40 40 40 40 B-8404 15 15 15 15 POLYCAT 5 0.90 0.90 0.90 0.90 DMCHA 0.60 0.60 0.60 0.60 Water 2.0 2.2 2.0 2.5 Hydrocarbon Inflating Agents 141 152 383 35.84 TOTAL 117.5 118.5 138.5 138.5 ISO A 147.23 148.4 145.77 180 Density, F.R. (pcf) 4.92 5.12 4.75 3.96 Initial K Factor (calorie cm / hrxcm2? ° C) .188 .184 .188 .171 SSC (Percentage of Change in Volume) 38 ° C, 100% Relative Humidity, 28 days +1.0 +1.1 -0.5 +2.16 70 ° C, 100% Relative Humidity, 28 days +2.1 +0.1 +2.2 +3.31 70 ° C, dry, 28 days +0.9 +5.3 0.0 +1.54 93 ° C, dry, 28 days +2.3 +2.7 +3.7 +2.74 93 ° C, dry, 7 days +0.3 -1.3 -0.1 +1.1 1 - cyclopentane 2 - HFC 134a 3 - HFC 235 ea 4 - HCFC 141b The dimensional stability of each sample under simulated conditions as a function of the blowing agent employed as recorded in Table 1, illustrates that the three polyol blends of the described component provide a large amount of flexibility to select a blowing agent for foaming agents. polyurethane for critical insulation applications. Regardless of whether the blowing agent is a hydrocarbon, such as cyclopentane, an HFC or HCFC, the polyol mixture described herein when used in a formulated system provides excellent dimensional stability under a number of service conditions.

Claims (40)

R E I V I N D I C L I O N E S:

1. A storage stable polyol composition comprising: a) a polyoxyalkylene polyether polyol initiated with aromatic amine having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more; b) a polyoxyalkylene polyether polyol initiated with aliphatic amine having a hydroxyl number of 200 milliequivalent polyol per gram of KOH or more; c) an aromatic polyester polyol having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more; and d) a blowing agent that is selected from the group consisting of cyclopentane, HFC, HCFC and mixtures thereof; wherein the blowing agent is dissolved in the polyol composition.

The composition according to claim 1, wherein the polyol c) is present in an amount of about 18.0 weight percent or less, based on the weight of the polyol composition.

3. The composition according to claim 1, wherein the amount of the blowing agent is at least about 5.0 weight percent, based on the weight of the polyol composition.

4. The composition according to claim 3, wherein the polyols a) and b) together comprise polyols obtained by co-initiating the aromatic amine and the aliphatic amine with an alkylene oxide.

The composition according to claim 4, wherein the polyol composition further comprises a hydroxyl functional polyoxyalkylene polyether polyol having an average nominal functionality of at least 5.

The composition according to claim 5 , wherein the average hydroxyl number of the polyols in the polyol composition is at least 350 milliequivalents of polyol per gram of KOH or more.

The composition according to claim 6, wherein the amount of the polyols a), b) and c) is 50 weight percent or less, based on the weight of all the polyols in the polyol composition having a number average molecular weight of at least 200.

The composition according to claim 4, wherein each of the polyols a) and b) contains at least 50 weight percent of polyoxypropylene groups based on the weight of all oxyalkylene groups.

The composition according to claim 1, wherein the polyol composition further comprises water in an amount of about 0.05 percent to 4 percent by weight.

The composition according to claim 1, wherein the polyol composition further comprises a hydroxyl functional polyoxyalkylene polyether polyol having an average nominal functionality of at least 5.

The composition according to claim 1 , wherein the average hydroxyl number of all polyols having a number average molecular weight of at least 200 is at least 350 milliequivalents of polyol per gram of KOH.

The composition according to claim 1, wherein the amount of the polyols a), b) and c) is about 50 weight percent or less, based on the weight of all the polyols in the polyol composition which it has a number average molecular weight of 200 or more.

The composition according to claim 1, wherein the polyols a) and b) contain at least 50 weight percent of polyoxypropylene groups based on the weight of all the oxyalkylene groups used in the manufacture of the polyols a ) and b).

14. A rigid closed cell foam based on polyisocyanate comprising the reaction product of an organic isocyanate as a polyol composition in the presence of a blowing agent, the polyol composition comprising: a) a polyoxyalkylene polyether polyol initiated with aromatic amine having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more; b) a polyoxyalkylene polyether polyol initiated with aliphatic amine having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more; and c) an aromatic polyester polyol having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more; the blowing agent comprises a blowing agent which is selected from the group consisting of cyclopentane, HFC, HCFC and mixtures thereof in an amount of at least 5.0 weight percent based on the weight of the polyol composition.

15. The foam according to claim 14, wherein the polyol c) is present in an amount of about 18.0 weight percent or less, based on the weight of the polyol composition.

16. The foam according to claim 14, wherein the polyols a) and b) together comprise polyols which are obtained by co-initiating the aromatic amine and the aliphatic amine with an alkylene oxide.

17. The foam according to claim 16, wherein the polyol composition further comprises a hydroxyl-functional polyoxyalkylene polyether polyol having an average nominal functionality of at least 5.

The foam according to claim. 17, wherein the average hydroxyl number of the polyols in the polyol composition is at least 350 milliequivalents of polyol per gram of KOH.

19. The foam according to claim 18, wherein the amount of the polyols a), b) and c) is at least 50 weight percent based on the weight of all the polyols in the polyol composition having a number average molecular weight of at least 200.

The foam according to claim 16, wherein each of the polyols a) and b) contains at least 50 weight percent of polyoxypropylene groups based on the weight of all oxyalkylene groups.

21. The foam according to claim 14, wherein the polyol composition further comprises water in an amount of about 0.05 percent to 4 percent by weight.

22. The foam according to claim 14, wherein the polyol composition further comprises a hydroxyl functional polyoxyalkylene polyether polyol having an average nominal functionality of at least 5.

The foam according to claim 14 , wherein the average hydroxyl number of all polyols having a number average molecular weight of at least 200 is at least 350 milliequivalents of polyol per gram of KOH.

24. The foam according to claim 14, wherein the amount of the polyols a), b) and c) is 50 weight percent or less based on the weight of all the polyols in the polyol composition having a number average molecular weight of at least 200.

The foam according to claim 14, wherein the polyols a) and b) contain at least 50 weight percent of polyoxypropylene groups based on the weight of all the oxyalkylene groups used in the manufacture of the polyols a) and b).

26. The foam according to claim 14, wherein the foam has an initial k-factor of 0.198 cal centimeter / hour x square centimeter x ° C or less.

27. The foam according to claim 14, wherein the foam is dimensionally stable.

28. A method for manufacturing a rigid closed cell foam based on polyisocyanate comprising reacting an organic isocyanate with a polyol composition in the presence of a blowing agent, the polyol composition comprising: a) a polyoxyalkylene polyether polyol. initiated with aromatic amine having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more; b) a polyoxyalkylene polyether polyol initiated with aliphatic amine having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH; c) an aromatic polyester polyol having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more, in an amount of 18.0 weight percent or less, based on the weight of the polyol composition; and d) a blowing agent that is selected from the group consisting of cyclopentane, HFC, HCFC and mixtures thereof, present in an amount of at least about 5.0 weight percent based on the weight of the polyol composition.

29. The method according to claim 28, wherein the polyols a) and b) together comprise polyols obtained by co-initiating the aromatic amine and the aliphatic amine with an alkylene oxide., and the polyol composition contains dissolved cyclopentane.

30. The method according to claim 29, wherein the polyol composition further comprises a hydroxyl functional polyoxyalkylene polyether polyol having an average nominal functionality of at least 5.

The method according to claim 30 , wherein the average hydroxyl number of the polyols in the polyol composition is at least 350 milliequivalents of polyol per gram of KOH.

32. The method according to claim 31, wherein the amount of polyols a), b) and c) is 50 weight percent or less, based on the weight of all polyols in the polyol composition having a weight molecular average in number of at least 200.

The method according to claim 29, wherein each of the polyols a) and b) contains at least about 50 weight percent of polyoxypropylene groups based on the weight of all oxyalkylene groups.

34. The method according to claim 29, wherein the polyol composition further comprises water in an amount of 0.05 percent to 4 percent by weight.

35. The method according to claim 28, wherein the polyol composition further comprises a hydroxyl functional polyoxyalkylene polyether polyol having an average nominal functionality of at least 5.

36. The method according to claim 28 , wherein the average hydroxyl number of all polyols having a number average molecular weight of at least 200 is at least 350 milliequivalents of polyol per gram of KOH.

37. The method according to claim 28, wherein the amount of polyols a), b) and c) is 50 weight percent or less based on the weight of all polyols in the polyol composition having an average molecular weight in number of at least 200.

38. The method according to claim 28, wherein the polyols a) and b) contain at least about 50 weight percent of polyoxypropylene groups, based on the weight of all the groups of oxyalkylene used in the manufacture of polyols a) and b).

39. The method according to claim 28, wherein the foam has an initial k-factor of 0.198 calorie centimeter / hour x square centimeter x ° C or less.

40. The method according to claim 28, wherein the foam is dimensionally stable. SUMMARY OF THE INVENTION A rigid closed cell foam based on polyisocyanate manufactured by reacting an organic isocyanate with a polyol composition in the presence of a blowing agent is now provided, wherein the polyol composition contains at least: a) a polyether polyol of polyoxyalkylene initiated with aromatic amine having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more; b) a polyoxyalkylene polyether polyol initiated with the aliphatic amine having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more; and c) an aromatic polyester polyol having a hydroxyl number of 200 milliequivalents of polyol per gram of KOH or more. The blowing agent is selected from the group consisting of cyclopentane, HFC, HCFC and mixtures thereof in an amount of 5.0 weight percent or more, based on the weight of the polyol composition. Preferably, the blowing agent is soluble in the polyol composition without sacrificing and advantageously improving the thermal insulation and the dimensional stability of the resulting polyurethane foam. Also disclosed is a storage stable polyol composition and methods for producing a rigid closed cell foam based on polyisocyanate.