Abstract: The flame retardancy of flexible polyurethane foams is increased by incorporation into the foam forming reactants of a low molecular weight, high primary hydroxyl trifunctional polyether polyol having a hydroxyl number between 300 and 500 and a primary hydroxyl content greater than 50 percent.

Abstract: A process for the production of expanded polyurea elastomers which comprises reacting:a) an aliphatic polyetheramine having primary amino functions and essentially no free hydroxyl groups;b) carbon dioxide in the form of carbamate, obtained by reacting carbon dioxide with a portion of the aliphatic polyetheramines;c) a polyisocyanate;d) water; ande) a catalyst having a tertiary amino group;in the presence off) an inert, halogen-free blowing agent.

Abstract: A process for the production of cellular plastics by the polyisocyanate polyaddition process, by reactinga) an organic and/or modified organic polyisocyanate withb) at least one relatively high-molecular-weight compound containing at least two reactive hydrogen atoms, and, if desired,c) a low-molecular-weight chain extender and/or crosslinking agent,in the presence ofd) a blowing agente) a catalyst andf) assistants and/or additives,wherein the blowing agent (d) usedd1) a low-boiling, fluorinated or perfluorinated tertiary alkylamine, ora mixture of (d1) and at least one physical or chemical blowing agent (d2) which is different from (d1), and blowing agent-containing emulsions comprising the abovementioned blowing agent (d1) or a blowing agent mixture of (d1) and (d2) and the starting components (a), (b), (c) or (b) and (c).

Abstract: The present invention relates to an improved process for producing, by means of a portable foaming apparatus having a static mixer, a polyurethane foam by reacting a reaction mixture comprised of a polyol, an organic isocyanate, a foaming/frothing agent, and a reaction catalyst, the improvement comprising employing monochlorodifluoromethane as at least a portion of said blowing/frothing agent in said reaction and employing an acid-blocked amine catalyst as at least a portion of said reaction catalyst in order to produce a CFC-free essentially closed-cell rigid or simi-rigid polyurethane foam.

Abstract: A method for producing a flexible polyurethane foam by the reaction of an active-hydrogen-containing component composed of an active hydrogen compound, a blowing agent, and an additive with an organic polyisocyanate compound: said blowing agent being carbon dioxide which is generated by the reaction of water with free isocyanate groups, said organic polyisocyanate compound being a mixture of diphenylmethane diisocyanates and polyphenylmethane polyisocyanate, which the mixture contains said diphenylmethane diisocyanate and said polyphenylmethane polyisocyanate in a mixing ratio of not more than 1.0 and 4,4'-MDI in a ratio of not more than 60% by weight based on the whole isocyanate mixture, and said polyphenylmethane polyisocyanate having an average functionality (hereinafter referred to as "f") of not less than 2.9 and containing diphenylmethane diisocyanate in an amount of less than 35% by weight.

Abstract: Preparation of a polyurethane and/or polyisocyanurate product by the reaction of a composition containing an organic polyisocyanate, an active hydrogen containing compound and water as a blowing agent using an effective amount of a molecular sieve containing sorbed amine catalyst and/or crosslinker.

Abstract: New particularly effective fire retardent elements based on foams and expandable graphite are characterized in that they additionally contain one or more components from the group consisting of phosphate-containing polyols, borates and amine salts.

Abstract: A high water, high resiliency polyurethane foam composition comprising polyisocyanate, conventional polyol, polymer polyol, diethanolamine, silicone surfactant, water and catalyst, the improvement which comprises a cycloaliphatic diamine of the following formula: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are independently hydrogen or a C.sub.1 -C.sub.4 alkyl group, and a catalyst composition consisting essentially of 0.05 to 0.3 parts gel catalyst and 0.075 to 0.5 parts acid-blocked blowing catalyst, per 100 parts polyol.

Abstract: The present invention relates to an improved essentially closed cell polyurethane foam comprising the reaction product of at least one polyol with at least one isocyanate, in the presence of water to provide a carbon dioxide blowing agent, the improvement comprising said reaction being effected in the presence of a catalyst system consisting essentially of N,N,N',N", N"-pentamethyl-diethylenetriamine and triethylene diamine in order to provide a polyurethane foam characterized by enhanced shrinkage resistance. Also claimed is a process for producing this foam.

Abstract: A process for the preparation of a hard foam containing urethane groups or containing urethane and isocyanurate groups involves reactinga) an organic and/or modified organic polyisocyanate withb) at least one high-molecular-weight compound containing at least two reactive hydrogen atoms and, if desired,c) a low-molecular-weight chain extender and/or cross-linking agent,in the presence ofd) a blowing agent,e) a catalyst and, if desired,f) assistants and/or additives,where the blowing agent (d) used is at least one organic carboxylic acid, preferably an aliphatic monocarboxylic acid, alone or in combination with water and/or a physical blowing agent, and the catalyst (e) used is a polyisocyanurate catalyst, preferably an alkali metal salt or ammonium salt of an organic carboxylic acid or tris(dialkylaminoalkyl)-s-hexahydrotriazine.

Abstract: The present invention is directed to a novel internal release agent, a mixture of isocyanate reactive materials containing the release agent and a RIM process using the release agent. The novel release agent is an ester prepared by reacting a specific tetrol with a mixture of a saturated and an unsaturated acid.

Abstract: Polyether polyols and polyurethane foams are stabilized by including therein a liquid stabilizer composition of (a) 2,6-di-tert-butyl-4-sec-butylphenol, (b) a reaction product of diisobutylene, styrene and diphenylamine and (c) phenothiazine or C.sub.9-26 -alkyl substituted phenothiazone and wherein the ratio of the phenol to the reaction product is about 1:5 to 5:1 and the ratio of the mixture of components (a) and (b) to the phenothiazone compound is about 5.0:0.1 to 4.0:1.0. The stabilizer composition may further contain trihydrocarbyl phosphite to stabilize the color of same.

Abstract: A method for producing a non-yellowing polyurethane urea foam, which comprises reacting an isocyanate-terminated prepolymer, obtained by the addition reaction of a polyol having a number average molecular weight of 100 to 5,000 and containing on the average 2 to 3 functional groups with an aliphatic polyisocyanate in an amount of 1.4 to 2.6 times the hydroxyl equivalent, with water in an amount of 0.4 to 5 times the isocyanate equivalent in the presence of, per 100 parts by weight of the prepolymer, 0.1 to 5 parts by weight of a carboxylic acid metal salt or 0.1 to 10 parts by weight of an amine-type catalyst.

Abstract: The present invention relates to a process for the preparation of low-density flexible polyurethane foams comprising reacting, in a closed mold, a mixture comprising polyisocyanates; compounds containing at least two isocyanate-reactive hydrogen atoms and having a molecular weight in the range from about 400 to about 10,000; water as blowing agent; optionally, compounds containing at least two isocyanate-reactive hydrogen atoms and having a molecular weight in the range from 32 to 399 as chain-extending and crosslinking agents; and optionally, one or more known auxiliaries and additives, wherein one or more of the reaction mixture components is heated before foaming to a temperature of at least 40.degree. C.

Abstract: A method for preparing a polyurethane foam which comprises reacting an organic polyisocyanate and a polyol in the presence of a blowing agent, a cell stabilizer and a catalyst composition consisting essentially of at least one compound of the following formula: ##STR1## where R is hydrogen, C.sub.1 -C.sub.8 alkyl, C.sub.6 -C.sub.10 aryl or C.sub.7 -C.sub.10 aralkyl, and n is 0-3. The preferred catalyst consists essentially of of the compound when n is 0, namely 3-quinuclidinol.

Abstract: Polyether polyols and polyurethane foams are stabilized by including therein a liquid stabilizer composition of (a) 2,6-di-tert-butyl-4-sec-butylphenol, (b) a reaction product of diisobutylene, styrene and diphenylamine and (c) phenothiazine or C.sub.9-26 -alkyl substituted phenothiazine and wherein the ratio of the phenol to the reaction product is about 1:5 to 5:1 and the ratio of the mixture of components (a) and (b) to the phenothiazine compound is about 5.0:0.1 to 4.0:1.0. The stabilizer composition may further contain trihydrocarbyl phosphite to stabilize the color of same.

Abstract: An improved method of using polymer compositions to produce foamed plastics, wherein a major, auxiliary source of blowing agent for the foam is the decomposition of dialkyl dicarbonates. The dialkyl dicarbonates can be decomposed over temperatures ranging from about 10.degree. C. to about 45.degree. C. when used in combination with particular tertiary amine decomposition catalysts. Enhanced production of carbon dioxide is obtained by the addition of water.

Abstract: The present invention relates to a process for preparing polyisocyanate polyaddition products by reacting(a) polyisocyanates with(b) relatively high molecular weight compounds containing at least two isocyanate-reactive hydrogen atoms and(c) chain-extending agents, in the presence of(d) N-(aminoalkyl)pyrrolidine catalysts corresponding to formula (I) ##STR1## in which R is a C.sub.2-12 alkylene group (optionally containing O or N atoms but not isocyanate-reactive groups) andR' is hydrogen or a C.sub.1-4 alkyl group,(e) optionally, other known catalysts, and(f) other known additives.

Abstract: Bisglycosides IGly--O--CHR.sup.2 --(CH.sub.2).sub.p --(XR.sup.1).sub.n --(CH.sub.2).sub.q --(CHR.sup.3).sub.m --O--Gly IwhereX is C--R.sup.4 or N,R.sup.1 is C.sub.1 -C.sub.30 -alkyl, C.sub.2 -C.sub.30 -alkenyl, O--C.sub.1 -C.sub.30 -alkyl or O--C.sub.2 -C.sub.30 -alkenyl when X is C--R.sup.4, and is CO--C.sub.1 -C.sub.30 -alkyl or CO--C.sub.2 -C.sub.30 -alkenyl when X is N,R.sup.2 to R.sup.4 are each hydrogen, C.sub.1 -C.sub.30 -alkyl or C.sub.2 -C.sub.30 -alkenyl,n is from 1 to 3,m is 0 or 1,p and q are each from 0 to 2 andGly is a mono- or disaccharide composed of aldopentoses,aldohexoses and/or ketohexoses,are used as surfactants or emulsifiers in detergents, cleaning agents and toiletries.

Abstract: A process for the production of an open cell polyurethane foam comprises the mixing of the following components at ambient temperatures in a mixing zone: a diisocyanate having a functionality of at least about 2.0, at least one hydrogen donor, at least one surfactant which is effective in forming an open cell polyurethane foam, at least one catalyst, and a blowing agent comprising a gas having a boiling point below approximately -100.degree. F. at atmospheric pressure which preferably comprises carbon dioxide. In addition, the mixture may also optionally contain water. The mixture is subjected to a pressure in said mixing zone which is sufficient to maintain the blowing agent in the liquid state at ambient temperatures. After mixing, the mixture is ejected from the mixing zone to atmospheric pressure, thereby completely and instantaneously vaporizing the blowing agent to provide expansion of the mixture. The resultant foam is then cured at ambient temperatures.

Abstract: A process for preparing polyurethane integral skin foam with low ozone depletion potential, which comprises mixing 100 pph of a polyether polyol, 5-50 pph of a chain extender, 0.1-2.0 pph of a surfactant, 0.01-0.20 pph of an amine and 0.01-0.20 pph of an organotin catalyst, 0-3.0 pph of a nucleating agent and 1.0-30 pph of a blowing agent comprising 50 to 100 weight percent of HCFC-123 and 50 to 0 weight percent of HCFC-141b to form a polyol mixture; blending said polyol mixture with isocyanate having an ISO index=0.95 to 1.10 and reacting said blend at a temperature from 0.degree.-70.degree. C. in a mold at a temperature of from 10.degree. to 90.degree. C. for a molding time of 1 to 9 minutes to form a polyurethane integral skin foam, and the product of said process.

Abstract: Hydrocarbon oils having a high aromaticity (at least 85%, preferably 95-100%) and a boiling point of about 342.degree. to about 510.degree. C. (about 650.degree. to about 950.degree. F.) are used as partial or total replacements for the foam stabilizers used in the preparation of both rigid, closed cell polyurethane foams and flexible, open cell polyurethane foams. These oils are useful as a replacement for both silicon surfactants and organic (i.e., non-silicon) surfactants. For certain blowing agents (e.g., trichlorofluoromethane and methylene chloride), hydrocarbon oils having a boiling point range of about 399.degree. to 454.degree. C. (about 750.degree. to about 850.degree. F.) are preferred. Highly aromatic oils having a boiling point of about 281.degree. to about 510.degree. C. are useful for reducing the vapor pressure of toluene diisocyanate and for preventing the low temperature crystallization of toluene diisocyanate or diphenylmethane diisocyanate.

Abstract: A modified organic polyisocyanate is prepared in such a manner that a trimerization catalyst, an organic phosphite estr, and a surfactant, and optionally a ferrocene compound are added to an organic isocyanate and/or a partially urethanized organic polyisocyanate to cause isocyanuration in an extent that not more than 20% by weight of entire isocyanate groups are isocyanurated; and a stopper is added, if necessary.

Abstract: A process for producing a rigid polyurethane foam by use of a decreased amount of a CFC blowing agent and an increased amount of water used as a blowing agent, maintaining a high degree of heat insulation and improving the deterioration in friability of the product. The catalyst is one of the imidazoles represented by the formula (I): ##STR1## where R.sup.1 is alkyl having 1 to 4 carbons, benzyl, dimethylaminopropyl, or hydroxyalkyl having 1 to 3 carbons; R.sup.2 is hydrogen, alkyl having 1 to 4 carbons, allyl, or benzyl; and R.sup.3 and R.sup.4 are independently hydrogen, methyl, or hydroxymethyl.

Abstract: A new class of compounds, is disclosed, defined by the formula:R'.sub.2 N(CH.sub.2 CH.sub.2 NR").sub.y Rwhere R, R' and R" are equal or different and are ##STR1## wherein x is bromine or chlorine, n is an integer from 3 to 5 inclusive and y is an integer equal to or greater than 1.The compounds of the invention are useful as fire retardant agents.

Abstract: Low density polyurethane foams having improved resistance to degradation of properties of compression set and flexibility when exposed to elevated temperatures and pressures are made by reacting a polyisocyanate of about 2.3 to 2.7 functionality at an isocyanate index of about 1.0 with a blend of polyols, catalysts, blowing agents and the like in which the polyols are a mixture of a polyether polyol having a molecular weight of at least 5,000 and a polymer polyol, and the catalysts are a mixture of a major portion of an amine catalyst and a minor portion of a metal catalyst. The foams made by this invention are particularly well suited for use as components of sport shoes that are asembled by vulcanization.

Abstract: A method is disclosed for the preparation of flexible polyester polyurethane foam by reaction of at least difunctional polyesterols with at least difunctional organic isocyanates in the presence of catalysts and a stabilizer mixture of organic and organosilicon compounds, water, optionally blowing agents and optionally conventional additives, wherein the stabilizer mixture used comprisesa) a (meth)allyl polyoxyalkylene ether polymer or its copolymer with vinyl monomers andb) a polyoxyethylene-polysiloxane block copolymer,in a ratio by weight of a:b of 1:9 to 9:1. The polyester foam obtained are open celled to a high degree and have an excellent die-cuttability.

Abstract: The invention relates to a process for the production of polyamide imides from diimidodicarboxylic acids, trimellitic imidocarboxylic acids and diisocyanates and to their use as moldings, films and binders for paints.

Abstract: A method of using blowing agent compositions to produce foamed plastics such as polyurethanes, polyesters and the like, wherein a major auxiliary source of blowing agent for the foam is the decomposition of dialkyl dicarbonates. The dialkyl dicarbonates can be decomposed over temperatures ranging from about 10.degree. C. to about 45.degree. C. when used in combination with particular tertiary amine decomposition catalysts.

Abstract: A process for manufacture of molded, high resiliency, polyurethane foam substantially free of volatile organic blowing agents comprising feeding at least three streams into a mixing device to form a reaction mixture, wherein a first stream contains (i) a polyol, (ii) water, (iii) a catalyst, (iv) a surfactant; a second stream contains an organic polyisocyanate; and a third stream contains (i) water, (ii) a crosslinking/extending agent, and (iii) a process/foam modifier.

Abstract: A method for preparing a polyurethane foam which comprises reacting inorganic polyisocyanate and a polyol in the presence of a catalyst composition comprising a blowing catalyst and a gelling catalyst, the improvement which comprises employing a blowing catalyst consisting essentially of(a) 25 to 80 wt % pentamethyldiethylenetriamine and(b) 20 to 75 wt % bis(dimethylaminopropyl)methylamine.The catalyst composition provides the resulting polyurethane foam with improved breathability.

Abstract: A method for preparing a polyurethane foam which comprises reacting inorganic polyisocyanate and a polyol in the presence of a catalyst composition comprising a blowing catalyst and a gelling catalyst, the improvement which comprises employing a blowing catalyst consisting essentially of(a) 25 to 80 wt % pentamethyldiethylenetriamine and(b) 20 to 75 wt % bis(dimethylaminopropyl)methylamine.The catalyst composition provides the resulting polyurethane foam with improved breathability.

Abstract: The present invention pertains to a composition of matter and to a method of using the composition to produce foamed plastics, wherein a major, auxiliary source of blowing agent for the foam is the decomposition of dialkyl dicarbonates. The dialkyl dicarbonates can be decomposed over temperatures ranging from about 10.degree. C. to about 45.degree. C. when used in combination with particular tertiary amine decomposition catalysts.

Abstract: Polyurethane foams, varying in nature from soft to hard, tough skin and a process for their preparation comprising reacting approximately equal volumes of substantially liquid mixtures from a two part dispensing system, Part A comprising a substantially liquid, stable mixture of an isocyanate and an epoxide and Part B comprising a substantially liquid mixture of a polyether polyol, a catalyst and an accelerator.

Abstract: Improved reinforced polyurethane/urea articles are made by reacting an organic polyisocyanate with low viscosity imino/enamine-functional compounds in contact with fiberous reinforcing agents.

Abstract: Described is a lightweight open-cell flexible foam having a density no greater than about 6 pounds per cubic foot, preferably less than 1.0 pound per cubic foot (pcf) comprising the reaction product of an organic polyisocyanate and a mixture of difunctional acids, acid anhydrides, and difunctional anhydrides in the presence of a tertiary amine triazine catalyst, which reactants during the manufacturing process generate carbon dioxide, wherein the ratio of imide groups in the final product is greater than 1.

Abstract: A shock-absorbing polyurethane foam is formed of a polyol component and a polyisocyanate component. The polyol component is a mixed polyol having an average hydroxyl number of 130-250 and composed at least of 20-70 parts by weight of a low-molecular polyol having a molecular weight of 300-500 and 80-30 parts by weight of a high-molecular polyol having a molecular weight of 1,500-8,000 per 100 parts by weight of the whole polyol component. The foam further contains 5-150 parts by weight of a plasticizer having a solidification point not higher than -20.degree. C. per 100 parts by weight of the whole polyol component. The foam can be produced by reacting the polyol component and polyisocyanate component in the presence of 5-150 parts by weight of the plasticizer per 100 parts by weight of the polyol component.

Abstract: The present invention pertains to a composition of matter and to a method of using the composition to produce foamed plastics, wherein a major, auxiliary source of blowing agent for the foam is the decomposition of dialkyl dicarbonates. The dialkyl dicarbonates can be decomposed over temperatures ranging from about 10.degree. C. to about 45.degree. C. when used in combination with particular tertiary amine decomposition catalysts.

Abstract: Described is a lightweight open-cell flexible foam having a density no greater than about 6 pounds per cubic foot, preferably less than 1.0 pound per cubic foot (pcf) comprising the reaction product of an organic polyisocyanate and a mixture of difunctional acids, acid anhydrides, and difunctional anhydrides in the presence of a tertiary amine triazine catalyst, which reactants during the manufacturing process generate carbon dioxide, wherein the ratio of imide to amide groups in the final product is greater than 1.

Abstract: A molded flexible polyurethane composition having improved polycarbonate compatibility comprising an organic polyisocyanate, a polyol and reactive tertiary amine catalyst. This catalyst contains at least one active hydrogen and/or hydroxyl group in its structure. Another embodiment of this invention relates to a molded flexible polyurethane composition having improved polycarbonate compatibility comprising an organic polyisocyanate, a polyol, a non-reactive tertiary amine catalyst and, an amine scavenger composition which may or may not also contain reactive tertiary amine catalysts. Also disclosed are processes for making said molded flexible polyurethane compositions having improved polycarbonate compatibility.

Abstract: A method for the manufacture of shock attenuating, low rebound polyurethanes in which polyols are reacted with polyisocyanates having a functionality of at least 2.3 at an isocyanate index of from about 65 to about 90.

Abstract: This invention relates to a process for the manufacture of polyurethane foams which exhibit a reduced tendency to stain vinyl films with which they are in contact, such as are produced for use in automobile interiors.

Abstract: A class of modified hydrophilic prepolymers and polymers is disclosed which are characterized by their specific reactivity. Isocyanate-capped oxyethylene-based prepolymers are modified by reacting with a compound having an isocyanate-reactive group which is a sulfhydryl group, an amino group, a hydroxyl group or a carboxyl group, and a non-isocyanate-reactive group, in quantities sufficient to modify at least a portion of the isocyanate groups of the prepolymer. Where said first functional group is an amino group contained in a diamine or polyamine compound or is a carboxyl group, the modifying compound is present in quantities sufficient to modify all or substantially all of the isocyanate groups of the prepolymer.

Abstract: Disclosed is a process for the catalyzed reaction of an isocyanate and an active hydrogen compound wherein the reaction is conducted in the presence of a novel catalyst comprising the salt of 1,8-diazo-bicyclo(5.4.0)undec-7-ene and a keto-enol of the formula ##STR1## where R is a non-acid containing cyclic residue. Preferred catalyzed reaction mixtures comprise Reaction Injection Molding urethanes (RIM). The novel catalyst salts provide a controlled induction period prior to the onset of gelation of the reaction mixture while providing complete cure of the reaction mixture thereafter.

Abstract: Polyether polyols and polyurethane foams are stabilized by including therein a stabilizer composition of 2,6-di-tert-butyl-4-sec-butylphenol and a reaction product of diisobutylene, styrene and diphenylamine wherein the ratio of the phenol to the reaction product is about 1:5 to 5:1. The stabilizer composition may further include trihydrocarbyl phosphite to stabilize the color of same.

Abstract: The present invention relates to the obtention of a rigid polyurethane compound, cellular or micro-cellular, reinforced or not, having a density ranging from 0.20 to 1.30 g/cm.sup.3 ; the formation of this compound happens through the mixing of a resin composed of a mixture of polyether and polyester polyols aminated or not, having a molecular weight ranging from 100 to 5000, employed at 5 to 100 parts by weight; surfactant based on dimethylpolysiloxane, employed at 0.1 to 5 parts by weight; amine catalysts of the tetramethylethylenediamine and dimethylcyclohexylamine type employed at 0.

Abstract: A foamable thermosetting resin system is disclosed comprising:(a) about 50 to about 85 weight percent, based on the weight of the composition, of a trimerisable polyisocyanate;(b) about 5 to about 20 weight percent of a liquid epoxy resin having an epoxy group content in the range from about 3500 to about 7500 mmol/kg;(c) about 5 to about 20 weight percent of a vinyl ester of a saturated aliphatic monocarboxylic acid in which the carboxyl group is attached to a tertiary or quarternary carbon atom;(d) about 1 to about 20 weight percent of a foaming agent, and(e) about 0.005 to about 5 weight percent of an isocyanate trimerization catalyst.

Abstract: A process for producing a polyurethane foam from a foam raw material containing polyols, organic isocyanates, catalysts and blowing agents, which comprises using as the polyols a high-molecular weight polyol having a hydroxyl number lower than 100 and a low-molecular weight polyol having a hydroxyl number higher than 200 which are mixed at a ratio of 4:6 to 6:4 (by weight), and also using as the catalysts a tertiary amine alone. Polyurethane forms having good buckling performance can be obtained by the process and they are expected to be useful as a packaging material, shock-absorbing material, heat-insulating material, and so on.

Abstract: New catalysts are made available for the production of polyurethane and polyepoxide resins being derivates of 2-azabicyclo[2.2.2]hept-5-enes and 2-azabicyclo[2.2.1]heptanes substituted in 2- and optionally in 3-position. Also provided is a process for preparing same by reacting cyclopentadiene with salts of strong acids of ammonia or of primary amines and aldehydes and, optionally, by subsequent catalytic hydrogenation of the reaction product.

Abstract: Rigid polyurethane foams produced by reacting a polyol component having a special composition with an isocyanate component in the presence of a blowing agent, a reaction catalyst and a foam stabilizer with a mold release time of as short as 5.5 minutes or less, have remarkably low thermal conductivity of 12.5.times.10.sup.-3 Kcal/m.hr..degree.C. or less and a low density and are suitable as heat insulating materials for refrigerators and the like.