Abstract: A method of making flexible polyurethane foams mixes a polyol (a hydroxyl group containing compound) with a cesium and/or rubidium fluoride catalyst, and reacts such mixture with at least one isocyanate. The cesium and/or rubidium fluoride may be used as the sole catalyst, replacing the blowing and gelling catalysts, such as amines, and metallic catalysts, such as a tin catalyst. Or, the cesium and/or rubidium fluoride may be used as a catalyst promoter in combination with traditional amine blowing and gelling catalysts and tin catalysts. The resulting flexible polyurethane foams exhibit increased thermal conductivity and lower levels of volatile organic compound emissions.

Abstract: A method of making flexible polyurethane foams mixes a polyol (a hydroxyl group containing compound) with a cesium and/or rubidium fluoride catalyst, and reacts such mixture with at least one isocyanate. The cesium and/or rubidium fluoride may be used as the sole catalyst, replacing the blowing and gelling catalysts, such as amines, and metallic catalysts, such as a tin catalyst. Or, the cesium and/or rubidium fluoride may be used as a catalyst promoter in combination with traditional amine blowing and gelling catalysts and tin catalysts. The resulting flexible polyurethane foams exhibit increased thermal conductivity and lower levels of volatile organic compound emissions.

Abstract: A membrane structure is provided. The membrane structure may include: a membrane; at least one hole extending into the membrane configured to receive a fluid. The membrane may include a plurality of electrodes arranged to provide one or more electric fields to control a movement of the fluid within the at least one hole.

Abstract: A composition comprising at least one source of metal ions and at least one additive obtainable by reacting a polyhydric alcohol comprising at least 5 hydroxyl functional groups with at least a first alkylene oxide and a second alkylene oxide from a mixture of the first alkylene oxide and the second alkylene oxide or a third alkylene oxide, a second alkylene oxide, and a first alkylene oxide in aforesaid sequence, the third alkylene oxide having a longer alkyl chain than the second alkylene oxide and the second alkylene oxide having a longer alkyl chain than the first alkylene oxide.

Abstract: Cross-linked rubbery polyurethane-ether polymeric membranes are made from cross-linked rubbery polyurethane-ether polymers that are synthesized from a diisocyanate-terminated polyether and a tetrol with four hydroxyl functional groups. The hydroxyl groups on the tetrol react with the isocyanate groups on the diisocyanate-terminated polyether to form urethane bonds. The cross-linked rubbery polyurethane-ether polymeric membrane selectively permeate condensable vapors such as C3 to C35 hydrocarbons, aromatics, water vapor, carbon dioxide, and hydrogen sulfide and rejects methane and ethane. The cross-linked rubbery polyurethane-ether polymeric membrane have high permeance for condensable vapors, high selectivity for condensable vapors over methane and ethane, and high resistance to liquid chemicals.

Abstract: A process for producing resilient, flexible polyurethane foams that function well in noise and vibration absorption applications for vehicle applications that are made from a blend of polyols (i) and an isocyanate (ii), wherein the blend of polyols (i) comprises a mixture of polyether polyols (i.a) that each has a hydroxyl equivalent weight of from 1200 to 3000 and at least 70% primary hydroxyl groups, from 5 to 80% by weight of the ethylene oxide-capped polypropylene oxides are nominally difunctional, from 0.5 to 20% by weight of the ethylene oxide-capped polypropylene oxides have a nominal functionality of four or higher, and the balance of the ethylene oxide-capped polypropylene oxides, but not less than 1.5% by weight thereof, are nominally trifunctional; an autocatalytic polyol (i.b) having a functionality in the range of 2 to 8 and a hydroxyl number in the range of 15 to 200, wherein said autocatalytic polyol compound comprising at least one tertiary amine group; and a low unsaturation polyol (i.

Abstract: A polyurethane or polyisocyanurate foam is prepared from a reaction mixture that includes comprising a polyol, an aromatic isocyanate compound, and a blowing agent. The polyol includes a poly(phenylene ether) having a number average molecular weight of 600 to 2000 atomic mass units and an average of 1.5 to 3 hydroxyl groups per molecule. The polyurethane or polyisocyanurate foam exhibits improved resistance to burning and/or reduced elapsed times to formation of tack-free foams relative to foams prepared without the poly(phenylene ether).

Abstract: An odor-absorbing foam composition comprising a cyclodextrin crosslinked with a polyurethane prepolymer. In one embodiment, the foam includes a ratio of the cyclodextrin to the polyurethane prepolymer selected to result in formation of the foam. The odor-absorbing foam may be used in a personal care product or wound care. A process for preparing a foam, including providing a cyclodextrin; providing a polyurethane prepolymer; combining the cyclodextrin with the polyurethane prepolymer; and allowing the polyurethane prepolymer to react with water and crosslink the cyclodextrin to form the foam. A process for preparing an odor-absorbing foam article such as a personal care product, including preparing the foam and applying it or the components thereof to a suitable substrate.

Abstract: This disclosure describes a method of making a polyurethane foam and a method of reducing NVH expected to be experienced by a substrate using the foam. When the foam is subjected to 95% relative humidity for a period of 7 days at a temperature of about 50° C., the foam absorbs an amount of water that is less than about 30% of the weight of the foam.

Abstract: Polyurethane foams which are highly flame resistant are described, as well as the production of such polyurethane foams by the reaction between a natural polyol, such as sucrose or a blend of mono- or disaccharides in place of the standard hydrocarbon-based polyol component, a polyisocyanate and water in the presence of a suitable polyurethane forming catalyst and a flame retardant, and optionally one or more components such as surfactants and/or emulsifiers. The resultant polyurethane foam has a bio-based solid content ranging from about 17% to 30%, may be formulated in a variety of foam densities for a variety of applications, and exhibits a high degree of fire and burn resistance, as exhibited by the flame spread index and the smoke spread values.

Abstract: Cardanol derivative comprising one or more units of the formula and a method for obtaining such cardanol derivative.

Abstract: A polyurethane foam is disclosed and described. The polyurethane foam is formed by combining a first component comprising at least one polyol with a second component comprising at least one polyisocyanate. The ratio of the number of isocyanate equivalents in the second component to the number of hydroxyl equivalents in the second component is less than 1.0. The foam exhibits low levels of free diisocyanate monomer, thereby reducing the amount of hazardous, volatile organic compounds. As a result, the foam can be prepared and installed without the need for ventilation equipment, external sources of fresh air, and the like.

Abstract: The invention relates to a process for preparing rigid polyurethane foams, which comprises reacting a) polyisocyanates with b) compounds having at least two hydrogen atoms reactive with isocyanate groups in the presence of c) blowing agents, wherein said compounds having at least two hydrogen atoms reactive with isocyanate groups b) comprise at least one polyether alcohol b1) having a functionality of 2-8 and a hydroxyl number of 200-800 mgKOH/g, obtained by addition of an alkylene oxide b1b) onto a compound having at least two hydrogen atoms b1a), hereinafter also known as starter substances, reactive with alkylene oxides by using an amine b1c) as catalyst.

Abstract: An organic aerogel including a polymer that is a reaction product of a substituted or unsubstituted alkyl cellulose compound or derivative thereof and a substituted or unsubstituted alkylene diphenyl diisocyanate compound, as well as a composition for the manufacture of an organic aerogel, and a method of manufacturing the organic aerogel.

Abstract: The invention relates to a foamed isocyanate-based polymer derived from a reaction mixture comprising an isocyanate, an active hydrogen-containing compound, a blowing agent and a highly branched polysaccharide which is derivatized with at least two esters of different length. Further the invention relates to a mix and a process for the production of isocyanate-based polymer. The mix for the production of a foamed isocyanate-based polymer comprises a mixture of the derivatized polysaccharide of the invention and an active hydrogen-containing compound. The process for producing a foamed isocyanate-based polymer comprises the steps of: contacting an isocyanate, an active hydrogen-containing compound, the derivatized highly branched polysaccharide of the invention and a blowing agent to form a reaction mixture and expanding the reaction mixture to produce the foamed isocyanate-based polymer.

Abstract: An odor-absorbing foam composition comprising a cyclodextrin crosslinked with a polyurethane prepolymer. In one embodiment, the foam includes a ratio of the cyclodextrin to the polyurethane prepolymer selected to result in formation of the foam. The odor-absorbing foam may be used in a personal care product or wound care. A process for preparing a foam, including providing a cyclodextrin; providing a polyurethane prepolymer; combining the cyclodextrin with the polyurethane prepolymer; and allowing the polyurethane prepolymer to react with water and crosslink the cyclodextrin to form the foam. A process for preparing an odor-absorbing foam article such as a personal care product, including preparing the foam and applying it or the components thereof to a suitable substrate.

Abstract: A polyisocyanate-based elastomer having a ratio of the storage modulus (E?) at 20° C. and the storage modulus (E?) at 120° C. of between 0.75 and 1.5, a tan ? at 100° C. of less than 0.1 and a maximum value of the tan ? of more than 0.8, the tan ? being the ratio of the loss modulus (E?) and the storage modulus (E?).

Abstract: The invention relates to a polyurethane obtainable by reacting a polyisocyanate and a polyol composition comprising a highly branched polysaccharide of randomly bonded glucopyranose units or an alkoxylated derivative of the same. The polysaccharide has an average number of 10–100 glucose residues and said polysaccharide and derivative both have an average functionality of 30 or more. The invention also relates to a process for the production of such a polyurethane as well as a mix for the production of a polyurethane comprising a polyol composition, comprising 2–100 % of a highly branched polysaccharide, at least one catalyst and at least one surfactant.

Abstract: Process for preparing a polyurethane elastomer having an apparent overall density of more than 150 kg/m3 comprising reacting a polyisocyanate and an isocyanate-reactive composition, optionally in the presence of water, wherein the reaction is conducted at an isocyanate index of 85 to 120, the polyisocyanate comprising: a) 80-100% by weight of a diphenylmethane diisocyanate comprising at least 40% by weight of 4,4?-diphenylmethane diisocyanate and/or a derivative of said diphenylmethane diisocyanate which derivative is liquid at 25° C.

Abstract: An embodiment of the present invention includes a foam prepared from a resin comprising: one or more saccharides; one or more isocyanates; one or more resin polyols; and water. The foam may be for example polyurethane foam or polycyanurate foam, either flexible or rigid. Another embodiment includes a method for preparing a foam comprising: forming a resin by mixing one or more saccharides with one or more isocyanates and then mixing the one or more saccharides and the one or more isocyanates with water; and admixing one or more foam polyols to the resin. Another embodiment includes a method for manufacturing a foam derived from an isocyanate, comprising replacing all or a portion of the isocyanate with a resin comprising: one or more saccharides; one or more isocyanates; one or more resin polyols; and water. Another embodiment includes an article of manufacture comprising such foam.

Abstract: A novel resin for binding composite lignocellulosic, cellulosic and non-cellulosic products is disclosed. The resin is comprised of one or more isocyanates, one or more saccharides, one or more polyols, and water. Preferaby, the saccharide is a polysaccharide comprised of corn syrup. Preferably, the isocyanate is a polyisocyanate and the polyol is an ethylene glycol. Also disclosed are methods for preparing and applying the resin as well as the products prepared from the resin.

Abstract: The polyisocyanate polyaddition products comprise hydrophobic compounds plus at least one further compound selected from the group consisting of: (i) organic, cyclic compounds having a molecular weight of from 200 to 3000 g/mol, (ii) salts of metals of transition groups I, II and/or VIII, (iii) organic and/or inorganic acid anhydrides, (iv) cyclic sulfonic esters and/or sulfones, (v) lactones, lactams and/or cyclic esters and/or (vi) &agr;,&bgr;-unsaturated carboxylic acids, &agr;,&bgr;-unsaturated carboxylic acid derivatives, &agr;,&bgr;-unsaturated ketones and/or &agr;,&bgr;-unsaturated aldehydes.

Abstract: Disclosed is a composition for preparing a rigid polyurethane foam having a good demolding property by defining polyol component and catalyst component. The polyol component comprises 40-60 wt. % of polyol obtained by polymerization with an organic oxide using sorbitol as an initiator, 5˜10 wt. % of polyol obtained by polymerization with an organic oxide using ethylene diamine as an initiator, 20˜30 wt. % of polyol obtained by polymerization with an organic oxide using toluene diamine or toluene diamine and triethanol amine as a single or a complex initiator, and, optionally, 5-20 wt. % of multivalent polyol of an ester structure, and the catalyst component is chosen in a group comprising a foaming catalyst, a gelling catalyst, a trimerization catalyst, a mixed form of the foaming catalyst and the gelling catalyst, and compound thereof.

Abstract: The present invention provides rigid foams made from aromatic polyester polyols and polyisocyanates. The foams are isocyanate-based foams and are preferably prepared without cell nucleating agents, and are formed from a mixture containing an aromatic polyester polyol, a polyisocyanate, and a blowing agent that includes water. The foams have a high closed cell content with cells having diameters of about 160 microns or less, high thermal resistance, and flame retardancy.

Abstract: Polyols initiated with a first initiator having a relatively high functionality averaging greater than eight and comprising a range of species of different functionality, and optionally a second initiator, having low functionality, i.e. a two to eight nominal functionality initiator molecule. Another aspect of the invention is a process for making the polyol. The invention is also directed to a process for producing polyurethane foam by reacting the polyol of the invention with isocyanates, and the foam produced thereby.

Abstract: Prepolymers which contain isocyanate groups, have an NCO content of at least 30.0% by weight and can be prepared by reacting an isocyanate mixture consisting predominantly of diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates and having a proportion of two-ring isomers of not more than 74% by weight with at least 4-functional polyols or a mixture of polyols having a mean functionality of at least 4, where the polyols or polyol mixtures have a hydroxyl number of from 200 to 1650 mg KOH/g and a number average molecular weight of less than 1100 g/mol.

Abstract: The polyisocyanate polyaddition products comprise hydrophobic compounds plus at least one further compound selected from the group consisting of: (i) organic, cyclic compounds having a molecular weight of from 200 to 3000 g/mol, (ii) salts of metals of transition groups I, II and/or VIII, (iii) organic and/or inorganic acid anhydrides, (iv) cyclic sulfonic esters and/or sulfones, (v) lactones, lactams and/or cyclic esters and/or (vi) &agr;,&bgr;-unsaturated carboxylic acids, &agr;,&bgr;-unsaturated carboxylic acid derivatives, &agr;,&bgr;-unsaturated ketones and/or &agr;,&bgr;-unsaturated aldehydes.

Abstract: Polyurethanes synthesized from sorbitol-branched polyester made by esterification of a diacid (or anhydride thereof diol, and sorbitol (or mixtures of same with other polyols).

Abstract: Flexible foams based on polyisocyanate polyaddition products are produced by reacting polyisocyanates with compounds which are reactive toward isocyanates in the presence of catalysts, blowing agents and, if desired, flame retardants, auxiliaries and/or additives, wherein polyether polyalcohols (c) which are obtainable by addition of alkylene oxides onto substances containing active hydrogens are used as substances which are reactive toward isocyanates, where, in a first stage, at least one substance (a) containing 2 or 3 active hydrogens is reacted with at least one alkylene oxide in the presence or absence of catalysts, subsequently at least one substance (b) which contains at least four active hydrogens and, if desired, further catalyst is added to the reaction mixture from the first stage and this mixture is then reacted in a second stage with at least one alkylene oxide.

Abstract: A polyurethane composition to provide a rigid polyurethane foam suitable for use as a core material in a composite laminate and which polyurethane composition includes an additive compound or oligomer-prepolymer having hydroxy groups for reaction with the diisocyanate of the polyurethane or which has been prereacted with a diisocyanate and which contains after the polyurethane reaction ethylenically unsaturated groups, like allyl or acrylic groups, to react with an unsaturated polyester resin. The invention includes the organic additive oligomer-prepolymer and the hybrid polyester-rigid polyurethane laminates.

Abstract: A polyol blend is disclosed for making polyurethane foams. The blend includes a first polyol having a functionality of about 2, a hydroxyl number ranging from about 20 to about 90, and an equivalent weight ranging from about 600 to about 2800; a second polyol having a functionality ranging from about 4 to about 8, a hydroxyl number ranging from about 200 to about 600, and an equivalent weight ranging from about 90 to about 280; and a third polyol having a functionality ranging from about 2.5 to about 4, a hydroxyl number ranging from about 15 to about 500, and an equivalent weight ranging from about 180 to about 4000. The polyol blend is capable of reacting with an isocyanate compound in the presence of water to produce a foam having a density ranging from about 0.5 to about 5 pounds/ft.sup.3, a compressive strength ranging from about 3 to about 20 psi, and an airflow ranging from about 10 to about 1000 cc/minute.

Abstract: The present invention discloses a foam frothing alternative for blowing or frothing single component foams using gases which are incapable of being liquified within the limits of DOT aerosol cans, referred to herein as non-liquefiable gases. In this invention, it is demonstrated that non-liquefiable gases such as CO.sub.2 and N.sub.2 O can be used to provide foams using conventional single component foam chemical raw materials. The present invention provides an adhesive/sealant, expanded by a non-liquefiable gas propelled from a container initially and expanded by a blowing agent consisting primarily or exclusively of a non-liquefiable gas and formulated from a moisture curable polyurethane prepolymer using a low molecular weight isocyanate of two or more functionality. In one or more variations, the compositions of the present invention contain solubility enhancers for non-liquefiable gases such as CO.sub.

Abstract: In a process for producing rigid polyurethane foams having improved heat distortion resistance and reduced thermal conductivity by reactinga) polyisocyanates withb) compounds containing hydrogen atoms reactive toward isocyanates, in the presence ofc) water, and, if desired,d) physically acting blowing agents ande) catalysts and known auxiliaries and/or additives, the compounds b) containing hydrogen atoms reactive toward isocyanates are a polyol mixture comprisingb1) a polyol which can be prepared by addition of ethylene oxide and/or propylene oxide onto a hexitol or a hexitol mixture, with the total hexitol content of the polyol mixture being from 15 to 30% by weight, based on the polyol mixture, andb2) a polyol which can be prepared by addition of ethylene oxide and/or propylene oxide onto one or more aromatic amines, with the total amine content of the polyol mixture being from 1 to 10% by weight, based on the polyol mixture, and the amount of the polyol mixture in the component b) is from 60 to 100 parts

Abstract: This invention relates to flexible foams and flexible molded foams prepared from an isocyanate component comprising an allophanate-modified diphenylmethane diisocyanate. The present invention also relates to processes for the production of these flexible foams and flexible molded foams.

Abstract: The present invention relates to a mixture of polyols for use in the preparation of polyurethane foam comprising:(i) 80-99% by weight of at least one polyether polyol and/or at least one polyester polyol; and(ii) 1-20% by weight of at least one polyolefin polyol.The invention further relates to a process for preparing polyurethane foams, using the said mixture of polyols; to polyurethane foams obtainable by such process; and to articles and composites containing the said polyurethane foams.

Abstract: Pressurized, blowing agent-containing isocyanate semiprepolymer mixtures advantageously having an isocyanate content of from 5 to 25% and based on organic polyisocyanates and alkoxylated lignin having a hydroxyl number of from 30 to 80, preferably in admixture with lignin-free polyhydroxyl compounds are used for producing single-component polyurethane foams.

Abstract: A polyisocyanate having an acid value of at least 0.01% HCl is used to produce polyisocyanate, polyisocyanurate and polyurethane urea foams with an HCFC blowing agent. The use of such a polyisocyanate is advantageous because the polyisocyanate does not cause significant decomposition of the HCFC blowing agent.

Abstract: A polyol blend is disclosed for making cellular polyurethane foam products in the absence of halogenated hydrocarbon blowing agents. The products have good insulating performance, good compressive strength, and excellent dimensional stability. The blend comprises first and second polyols and is suitable for one-shot and two component reaction systems. The first polyol is the reaction product of one or more alkylene oxides and a compound selected from the group consisting of aliphatic diols, triols, pentaerythritol, water in an amount sufficient to form a diol upon reaction with alkylene oxide, and mixtures thereof.

Abstract: Polyoxyalkylene polyether polyols suitable for preparation of flexible polyurethane foams are prepared by oxyalkylating an aqueous solution of one or more polyhydric, hydroxyl-functional solid initiators under conditions where both water as well as initiator are oxyalkylated. The polyols have calculated functionalities of between about 2.2 and 4.0 and hydroxyl numbers in the range of 10 to 180. The polyols may be used to prepare soft, high resiliency polyurethane flexible foams at low isocyanate indexes.

Abstract: Polyoxyalkylene polyether polyols suitable for preparation of flexible polyurethane foams are prepared by oxyalkylating an aqueous solution of one or more polyhydric, hydroxyl-functional solid initiators under conditions where both water as well as initiator are oxyalkylated. The polyols have calculated functionalities of between about 2.2 and 4.0 and hydroxyl numbers in the range of 10 to 180. The polyols may be used to prepare soft, high resiliency polyurethane flexible foams at low isocyanate indexes.

Abstract: There is now provided a closed cell rigid polyisocyanate based foam blowing with a C.sub.1 -C.sub.4 hydrofluorocarbon and water as blowing agents, which possesses a uniform density gradient varying by not more than 10 percent. There is also now provided a froth foaming mixture having good flow by employing a hydroxy terminated polyol which is pH neutral and a tertiary amine ether blow catalyst in an amount of 0.5 weight percent or more, using water and a C.sub.1 -C.sub.4 hydrofluorocarbon having a boiling point of 300.degree. K. or less as co-blowing agents.There is also provided a polyol composition having an average OH number of less than 400 and an average functionality of greater than 4, which when reacted with the isocyanate in the presence of a C.sub.1 -C.sub.4 hydrofluorocarbon, yields a rigid closed cell polyisocyanate based dimensionally stable foam.

Abstract: Sucrose-based polyether polyols which do not promote degradation of HCFC blowing agents are produced by blocking at least 10% of the polyol's hydroxyl groups with a compound represented by the formula CH.sub.3 COCH.sub.2 COOR in which R represents an alkyl group. These polyether polyols are particularly useful in the production of polyurethane foams.

Abstract: Foamed polyurethanes substantially free from non-uniform density distribution are obtained by dispersing an inert gas with mechanical stirring into a foamed polyurethane-forming composition containing substantially no blowing agent and comprising (1) an organic polyisocyanate component, (2) a polyol component comprising a high molecular weight polyol (A1) and a low molecular weight polyol (A2), (3) a dehydrating agent (B) and optionally organic microballoons, and curing the resulting composition containing therein the inert gas substantially homogeneously distributed. Foamed polyurethanes thus obtained are lightweight and of reduced warpage after processing and are suitable for model materials.

Abstract: Polyurethane foams can be prepared which have improved retention of insulative properties. The foams are prepared from formulations including a glycerine initiated ethoxylated polyol prepared from a formulation including from about two to about three moles of ethylene oxide per mole of glycerine initiator and/or a tri- to octa-functional substantially linear hydroxy alkane initiated ethylene carbonate ethoxylated polyol prepared from a formulation including from about 2 to about 15 moles of ethylene carbonate per mole of initiator wherein the ratio of moles of ethylene carbonate to initiator functionality is from 0.5 to less than 2.

Abstract: Two methods for preparing polyester-polyether polyols from polyalkylene terephthalates are disclosed. The first method comprises reacting the polyalkylene terephthalate with a solution of low molecular weight polyols and ethoxylated methyl glucoside at a suitable temperature, generally between about 370.degree. and 450.degree. F., and under vacuum distillation.The second method comprises dissolving the polyalkylene terephthalates in a mixture of low molecular weight polyols at a suitable temperature and under vacuum distillation to form the polyester polyol component. The polyether polyol component is made by reacting ethoxylated methyl glucoside with an alkylene oxide in the presence of a suitable catalyst. The final product is made by blending about 80-95% by weight of the polyester component with about 5-20% by weight of the polyether component.

Abstract: A method for preparation of rigid foam disclosed The method comprises mixing at least two components to form a reaction mixture. The reaction mixture comprises isocyanate, up to about 20% by weight CHClF.sub.2, up to about 2% by weight of water, and a combination of polyols having an overage OH number of from about 300 to about 500 and comprising polyalkoxylated glycerin having an OH number of from about 200 to about 300 and in which the alkoxy groups each have from two to about three carbon atoms. Related methods and compositions are also disclosed.

Abstract: Rigid isocyanurate foams having a substantially open cell structure are prepared by foaming a mixture of an organic polyisocyanate and a polyol having a NCO/OH equivalent ratio of 3.5 to 13.

Abstract: A polyurethane adhesive is prepared from a reaction mixture containing small amounts of chain extender material and a high equivalent weight of a polyol and a monoalcohol. An article adhered to a substrate using this adhesive is firmly affixed to the substrate, yet can be removed without leaving residual adhesive on the substrate. In addition, this adhesive can be washed and reused if desired.

Abstract: A polyol composition for producing rigid polyurethane foams which comprises:(a) a first polyol having the general formula of ##STR1## wherein R independently represents an ethylene group or a propylene group, m and n are integers of not less than 1, respectively, and m+n are in the range of 3-40, in amounts of 20-50% by weight based on the polyol composition; and(b) a second polyol selected from the group consisting of adducts of alkylene oxides to at least one member of three or more functional polyhydric alcohols and polyamino compounds.The resultant rigid polyurethane foams have high heat resistance and toughness as well as high mechanical properties, but have no voids therein.

Abstract: A rigid polyurethane foam obtained by foaming a special polyol component and an isocyanate component in the presence of a blowing agent comprising water and at least one member selected from the group consisting of 1,1-dichloro-2,2,2-trifluoroethane and 2,2-dichloro-2-monofluoroethane possesses balanced excellent properties, has no surface void, and shows only slight expansion after molding. Therefore, it can be effectively used as a heat insulator, in particular, a heat insulator for refrigerators.