Organic hydroxy silicates utilized as curing agents for polyurethane prepolymers

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BACKGROUND OF THE INVENTION

This invention relates to a process for curing liquid isocyanate-terminated polyurethane prepolymers by mixing them with 10% to 200% by weight, based on the weight of the prepolymer, of an aqueous dispersion or solution of an organic hydroxy silicate compound and their condensation products. This novel organic hydroxy silicate and their condensation products are effective both as a curing agents and as a low cost extender for polyurethane prepolymers. The products cured by this method may be quite varied in physical properties; they may be solid or porous, rigid or elastomeric, and the porous products may be rigid or soft and flexible.

The products produced by curing liquid isocyanate-terminated polyurethane prepolymer may be utilized as thermal insulating material, noise insulating material, shock-resistant packaging, cushions, as coating agents, as adehesives, as casting material, as constructional components of a building, etc.

The products have improved heat and flame resistant properties.

The organic hydroxy silicate compound and their condensation products utilized in this process may be produced by the process of the Claims and Examples in U.S. patent application Ser. No. 765,050, filed on Feb. 2, 1977, by David H. Blount. Details of the process to produce silicon acids, hydrated silica and silicoformic acid, and the process to produce organic hydroxy silicate compounds and their condensation products may be found in that U.S. patent application. The Infrared KBr Analysis of both the silicon acids and organic hydroxy silicate compounds were included in my U.S. patent application Ser. No. 765,050.

In U.S. patent application Ser. No. 663,924, filed on March 4, 1976, and U.S. patent application Ser. No. 599,000, filed on July 7, 1975, by David H. Blount, the silicon acids are reacted with polyisocyanate compounds, but not with liquid isocyanate-terminated polyurethane prepolymers. In U.S. Pat. Nos. 3,981,831; 3,975,316 and German Pat. No. 2,325,090, an aqueous silica sol and silicates were utilized in their process, but they did not utilize organic hydroxy silicate compounds and their condensation products to produce polyurethane products.

The silicon acids, hydrated silica and hydrated silica containing Si-H bonds may be produced by any of the commonly known methods. They are preferred to be in a fine granular form.

The silicon acids will react chemically with monohydroxy and polyhydroxy organic compounds to produce organic hydroxy silicate compounds and their condensation products. These novel organic hydroxy silicate compounds and condensation products will react chemically with isocyanates, organic acids, polycarboxylic acids and anhydrides and epoxy compounds.

The organic hydroxy silicate compounds and their condensation products are produced by chemically reacting a silicon acid, such as hydrated silica and hydrated silica containing Si-H groups with an organic hydroxy compound, by heating the mixture in the presence of an alkali catalyst to a temperature just below the boiling temperature of the organic hydroxyl compound while agitating for 20 to 60 minutes at ambient pressure, thereby producing organic hydroxy silicate compounds and their condensation products.

Various alkali compounds such as alkali metal carbonates, hydroxides, oxides and alkali metal salts of weak acids may be used as the alkali catalyst in the chemical reaction to produce organic hydroxy silicate compounds and their condensation products. The preferred alkali compound is sodium carbonate. Other useful alkali compounds are potassium carbonate, sodium hydroxide, potassium hydroxide and sodium silicate. Best results are obtained when the alkali catalyst is added in the amount of 1% to 10% of the weight of the reactants, hydrated silica and organic hydroxyl compound. The alkali catalyst is necessary in this process because when an organic hydroxyl compound is heated with hydrated silica without an alkali catalyst, no organic hydroxy silicate compound is produced. It is possible to produce a colloidal dispersion of silica hydrogel in polyols when a silica hydrogel is heated in a polyol while agitating without the presence of an alkali catalyst, but not an organic hydroxy silicate compound. Infrared analysis of a colloidal dispersion of silica hydrogen in polyols shows that the polyol does not react with the silica.

Various monohydroxy compounds may be used in this process to to produce organic hydroxyl silicate compounds such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, amyl, hexyl, octyl, benzyl and allyl alcohols and thioalcohols, phenols, cresols, thiophenols, cyclohexanol, methylcyclohexanol, cyclohexano-methanol, methallyl alcohol thiocresols, halogenated alcohols and mixtures thereof.

Various polyhydroxyl compounds may be used in this process to produce organic hydroxyl silicate compounds and their condensation products such as glycerol, glycerol monochlorohydrin, ethylene glycol, propylene glycol, butylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tetraethylene glycol, polyethylene glycols, ether glycols, Bisphenol A, resorcinol bis (beta-hydroxyethyl) terephthalate, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol, pentaerythritol, trimethol propane, trimethol ethane, 2,2-oxydiethanol, glucose, mannose, fructose, molasses, cane sugar, dextrines, starches, corn syrup, maple syrup, castor oil and mixtures thereof.

Various organic compounds containing hydroxyl radicals may be used to produce organic hydroxy silicate compounds such as glycolic acid, malic acid, 10 hydroxy undecanoic acid, 2-hydroxy decanoic acid, 10 hydroxy pentadecanoic acid, monoglycerides of fatty acids, halogenated alcohols, etc. and mixtures thereof.

One part by weight of an organic hydroxyl silicate compound and polymer, containing 0 to 1 part by weight of water may be reacted with 0.5 to 6 parts by weight of a liquid isocyanate-terminated polyurethane prepolymer to produce a solid/solid fine cellular polyurethane product.

Any suitable polyisocyanate may be used to produce the liquid isocyanate-terminated polyurethane prepolymer, for example, arylene polyisocyanates such as tolylene, metaphenylene, 4-chlorophenylene-1,3-, methylene-bis-(phenylene-4-), biphenylene-4,4'-, 3,3'-dimethoxy-biphenylene-4,4'-, 3,3'-diphenylbiphenylene-4,4'-, naphthalene-1,5- and tetrahydronaphthalene-1,5-diisocyanates and triphenylmethane triisocyanate; alkylene polyisocyanates such as ethylene, ethylidene, propylene-1,2-, butylene-1,4-, butylene-1,3-, hexylene-1,6-, decamethylene-1,10-, cyclohexylene-1,2-, cyclohexylene-1,4-, and methylene-bis-(cyclohexyl-4,4'-) diisocyanates. Phosgenation product of aniline-formaldehyde condensation may be used. Polyisothiocyanate, inorganic polyisothiocyanates, polyisocyanates which contain carbodiimide groups as described in German Pat. No. 1,092,007 and polyisocyanates which contain urethane groups, allophanate groups, isocyanurate groups, urea groups, imide groups or biuret groups may be used to produce the liquid isocyanate-terminated polyurethane prepolymers.

SUMMARY OF THE INVENTION

I have discovered that an aqueous solution or dispersion of organic hydroxy silicate compounds and their condensation products will react chemically with liquid isocyanate-terminated polyurethane prepolymers to produce cured polyurethane products.

Water is mixed with the organic hydroxy silicate compounds and their condensation products in the amount of 10% to 100% by weight, based on the weight of the organic hydroxy silicate compound and their condensation products. The pH of the mixture may be 6 to 12.

Any of the commonly known isocyanate-terminated liquid polyurethane prepolymers may be reacted with and cured by the aqueous solution or dispersion of organic hydroxy silicate compounds and their condensation products.

As is known in the art, the isocyanate-terminated liquid polyurethane prepolymers may be made by reacting organic polyisocyanates in molar excess with hydroxyl containing or carboxyl-containing polyesters, polyethers, polysulfides, polybutadienes, butadiene-acrylonitrile copolymer and butadiene-styrene copolymer, polyepichlorohydrin, polythioethers, polyester amides, polyacetals, urea formaldehyde resins, polycarbonates and other polyols. The polyesters may be produced by any of the commonly known methods. The polyether polyols are useful in making polyurethane prepolymers, and the methods to produce them are well known in the art. The hydroxyl-group-containing polysulfide polymers maybe utilized to produce polyurethane prepolymers.

Any suitable polyisocyanate may be reacted with the above-described hydroxyl-containing polymers to prepare the isocyanate-terminated polyurethane prepolymers such as the arylene polyisocyanates, alkylene polyisocyanates and triphenylmethane triisocyanate as previously listed in this invention. Toluene diisocyanates are preferred, especially a mixture of 80% of the 2,4-isomer and 20% of the 2,6-isomer thereof.

Plasticizers, fillers, curing rate modifiers, pigments, extender and the like maybe added to the polyurethane prepolymer or may be added at the time of curing and may be in the amount from 5% to 50% by weight, based on the prepolymer. Plasticizers may include benzoate ester, phthalate esters, dipropylene glycol benzoate, dodecyl phthalate and propylene glycol phthalate. Extenders such as high boiling coal tar distillates, mineral oil, poly (alpha-methyl styrene) polymers, mercapto-terminated liquid polysulfide polymers, paraffin oil and sulphonated castor oil may be used. Finely divided fillers such as alkali metal silicates, alkaline earth metal silicate, ammonium silicate, metal oxides, metal hydroxides, metal carbonates, chalk, heavy spar, gypsum, anhydrite, clay, kaolin, silica, and mixtures thereof may be used in this instant process.

In the production of certain foams, it is advisable to add blowing agents. These are inert liquids with boiling points ranging from -25.degree. to 80.degree. C. and preferably from -15.degree. to 40.degree. . The organic blowing agents are used in quantities of from 2% to 30% by weight, based on the reaction mixture.

The organic blowing agents such as acetone, ethyl acetate, methanol, ethanol, halogenated alkanes, e.g. methylene chloride, chloroform, ethylidene chloride vinylidene chloride, monofluorotrichloromethane, chlorodifluoromethane, dichlorodifluoromethane, butane, hexane, heptane, diethylether, compounds which decompose at temperatures above room temperature with liberation of gases, e.g. nitrogen, such as azo compounds and azoisobutyric acid nitrile, may be used in this process.

Other catalysts in place of or combined with water may be utilized as the catalyst to produce foam products from the liquid isocyanate-terminated polyurethane prepolymers and organic hydroxyl silicate compounds and their condensation product. These catalysts are commonly known in the arts such as tertiary amines, silaamines, basic compounds which contain nitrogen e.g. tetraalkylammonium hydroxides, alkali metal hydroxides, alkali phenolates, alkali metal alcolates, hexahydrotriazines, tin organo-metallic and mixtures thereof. These catalysts are generally used in a quantity of from 0.001% to 10% by weight, based on the weight of the polyurethane prepolymer.

Suitable emulsifiers and foam stabilizers may also be used according to this invention. Suitable emulsifiers are, e.g. the sodium salts of ricinoleic sulphonates or of fatty acids; or salts of fatty acids with amines, e.g. oleic acid diethylamine or stearic acid diethanolamine; or alkali metal or ammonium salts of sulphonic acids and fatty acids. These additives are preferably used in quantities of from 0% to 20%, by weight, based on the reaction mixtures.

Suitable foam stabilizers are mainly water-soluble polyether siloxanes and those described in U.S. Pat. No. 3,629,308. These additives are preferably used in quantities of from 0% to 20%, by weight, based on the reaction mixture.

Further examples of surface active additives, foam stabilizers, cell regulators, negative catalysts, stabilizers, flame retarding substances, plasticizers, dyes, fillers and fungicidal and bacteriocidal substances and details about methods of using these additives and their actions may be found in Kunststoff-Handbuch, Volume VI, published by Vieweg and Hochtlen, Carl-Hanser-Verlag, Munich 1966, e.g. on page 103 to 113.

The polyurethane prepolymer with only two terminal isocyanate groups tend to produce non-porous products when reacted with an organic hydroxy silicate compound and polymer containing 10 to 100%, by weight of water. The polyurethane prepolymer with 3 or more terminal isocyanate groups tend to produce cellular products when reacted with an organic hydroxy silicate compound and polymer containing 10% to 100% by weight of water. The polyurethane prepolymer, when reacted with an organic hydroxy silicate compound and polymer without water added, tends to produce non-porous products. Mixtures of polyurethane prepolymer with three and four terminal isocyanate groups and cured by reacting with an organic hydroxy silicate compound and polymer containing 10% to 100% by weight produce tough, strong, finely cellular, light weight polyurethane product which is useful for structural applications. The three and four terminal isocyanate groups may be mixed to contain from 20% to 80% by weight of the prepolymer having three isocyanate groups, and from 80% to 20% by weight of the prepolymer having four isocyanate groups.

The object of the present invention is to provide a novel method of curing liquid isocyanate-terminated polyurethane prepolymers. Another object and advantage of the present invention is to utilize low cost and ready availability of organic hydroxy silicate compounds and their condensation products to cure urethane prepolymers. Another object is to produce relatively low cost elastomeric and foamed polyurethane polymers having good physical properties. Another object of the present invention is to produce polyurethane polymers with improved flame resistant properties. Still a further object to provide novel relatively low cost, rigid, fine cellular, light-weight polyurethane polymers which may be used for structural purposes. Still another object is to produce novel polyurethane polymers that are soluble in organic solvent and may be utilized as coating agents for wood and metal.

DESCRIPTION OF PREFERRED EMBODIMENT

My invention will be illustrated in greater detail by the specific examples which follow, it being understood that these preferred embodiments are illustrative of, but not limited to, procedures which may be used in the production of polyurethane polymer utilizing organic hydroxy silicates as the curing agent. Parts and percentages are by weight unless otherwise indicated.

EXAMPLE I

About equal parts by weight of fine granular hydrated silica and glycerol are mixed, then 5% by weight of sodium carbonate, percentage based on the weight of the hydrated silica and glycerol, is added. The mixture is then heated to just below the boiling point of glycerol for 20 to 30 minutes while agitating at ambient pressure, thereby producing brown granules of glycerol silicate. On further heating of the glycerol silicate at a temperature just below the boiling point of glycerol for 10 to 30 minutes, the glycerol silicate granules soften, then form a brown poly(glycerol silicate) polymer.

The mixture of glycerol silicate and poly(glycerol silicate) polymer were analyzed by Infrared KBr disc analysis and it showed evidence that the hydrated silica reacted chemically with the glycerol.

About 2 parts by weight of a liquid isocyanate-terminated polyurethane prepolymer, which was produced by mixing about equal parts by weight of toluene diisocyanate (80% 2,4-isomer and 20% 2,6-isomer) and polyethylene glycol (380-420 mol wt.) and 1 part by weight of the said mixture of glycerol silicate and poly(glycerol silicate) polymer, containing about 10% water by weight, are mixed. The mixture is gently agitated at ambient temperature for 5 to 15 minutes until the mixture begins to expand. The mixture expands 8 to 10 times its original volume and is cured within 30 to 60 minutes, thereby producing a white, rigid, tough polyurethane foam.

EXAMPLE II

About equal parts by weight of the mixture of glycerol silicate and poly (glycerol silicate) polymer as produced in Example I and water are mixed. Then equal parts by weight of the polyurethane prepolymer produced in Example I are mixed. The mixture is then gently agitated for 5 to 15 minutes until it begins to expand. The mixture expands 4 to 6 times its original volume, thereby producing a tough semirigid foam in 30 to 60 minutes.

EXAMPLE III

About 1 part by weight of the mixture of glycerol silicate and poly (glycerol silicate) polymer as produced in Example I and 0.5 part by weight of water are mixed, then equal parts by weight of the polyurethane prepolymer as produced in Example I are mixed. The mixture is gently agitated for 5 to 15 minutes until it begins to expand. The mixture expands 4 to 6 times its original volume, thereby producing a tough, elastic, semirigid, foam and is cured in 30 to 60 minutes.

EXAMPLE IV

About equal parts by weight of castor oil and toluene diisocyanate (80% 2,4-isomer and 20% 2,6-isomer) are mixed and agitated gently until the chemical reaction has stopped, thereby producing a polyurethane prepolymer.

About 2 parts by weight of the polyurethane prepolymer as produced above and 1 part by weight of a catalyst, an aqueous solution of the mixture of glycerol silicate and poly(glycerol silicate) polymer as produced in Example I containing 25% by weight of water, are mixed. The mixture is gently agitated for 5 to 15 minutes until it begins to expand. The mixture expands 6 to 8 times its original volume, thereby producing a white, tough, semi-rigid polyurethane foam, a fine cellular product.

EXAMPLE V

About 1 part by weight of hydrated silica (SiO.sub.2 .times.H.sub.2 O) and about 1.5 parts by weight of propylene glycol and 1 to 10% sodium carbonate are mixed then heated to just below the boiling point of propylene glycol (150.degree. to 180.degree. C.) while agitating for 30 to 90 minutes at ambient pressure thereby producing brown granules of propylene glycol silicate and poly(propylene glycol silicate) polymer.

About 2 parts by weight of the polyurethane prepolymer as produced in Example I and 1 part by weight of the mixture of propylene glycol silicate and poly(propylene glycol silicate) polymer, containing about 10% water, are mixed then agitated gently for 5 to 15 minutes until the mixture begins to expand. The mixture expands 8 to 12 times its original volume and is cured in 30 to 60 minutes, thereby producing a white, tough, rigid, polyurethane foam, a fine cellular product.

EXAMPLE VI

About 1 part of the mixture of propylene silicate and poly(propylene silicate) polymer as produced in Example V and 0.5 parts by weight of water are mixed; then 1 part by weight of the mixture is mixed with 1.5 parts by weight of the polyurethane prepolymer as produced in Example IV. The mixture is then gently agitated at ambient pressure for 5 to 15 minutes until the mixture begins to expand. The mixture expands 6 to 8 times its original volume, thereby producing a white, tough, semirigid fine cellular product.

EXAMPLE VII

About 1.5 parts by weight of 2,2'-oxydiethanol, 1 part by weight of fine granular hydrated silica and 0.2 parts by weight of sodium silicate are mixed then heated to just below the boiling temperature of 2,2'-oxydiethanol while agitating for 20 to 90 minutes, thereby producing a thick, light brown, liquid mixture of 2,2'-oxydiethanol silicate and poly(2,2'-oxydiethanol silicate) polymer.

About equal parts by weight of unsaturated polyester resin, containing about 20% styrene and toluene diisocyanate (80% 2,4-isomer and 20% 2,6-isomer) were mixed at ambient temperature. About 2 parts of the above mixture were mixed with 1 part by weight of the mixture of 2,2'-oxydiethanol silicate and poly(2,2'-oxydiethanol silicate) polymer. The mixture was gently agitated at ambient pressure and temperature for 5 to 15 minutes until the mixture began to expand. The mixture expands 4 to 6 times its original volume, thereby producing a rigid, cream colored, fine cellular polyurethane product.

EXAMPLE VIII

A polyester, having about 2,000 to 2,200 molecular weight and produced by condensation of a mixture of about 70% ethylene glycol and 30% propylene glycol with equimolar amount of adipic acid, was reacted with tolylene diisocyanate to produce a urethane prepolymer having an NOC content of about 3.5%.

About 4 parts by weight of the above polyurethane prepolymer was mixed with 1 part by weight of an aqueous solution of the mixture of propylene silicate and poly(propylene silicate) polymers containing 40% water, then the mixture was gently agitated for 5 to 15 minutes at ambient temperature and pressure. The mixture is allowed to cure for 12 to 24 hours, thereby producing a white, tough elastomer.

EXAMPLE IX

About 1 part by weight of a fine granular hydrated silica, 5 parts by weight of a 35% aqueous solution of 2-butyne-1,4-diol and 1 to 10% potassium carbonate are mixed then heated to 80 degree to 120 degree C. while agitating for 20 to 90 minutes, thereby producing a light, brown mixture of 2-butyne-1,4-diol silicate and poly(2-butyne-1,4-diol silicate) polymer.

About 3 parts by weight of the polyurethane prepolymer as produced in Example VIII and 1 part by weight of an aqueous solution containing 70% by weight of the mixture of 2-butyne-1,4 diol silicate and poly(2-butyne-1,4-diol silicate) polymer are mixed thoroughly and then cured at ambient temperature and pressure for 12 to 24 hours, thereby producing a white tough elastomer.

EXAMPLE X

About 1 part by weight of fine granular hydrated silica, 3 parts by weight of triethylene glycol and 1% to 10% sodium carbonate are mixed then heated to a temperature near the boiling point of triethylene glycol (150 degrees to 250 degrees C.) while agitating at ambient pressure for 20 to 90 minutes, thereby producing a light brown, liquid mixture of triethylene glycol silicate and poly(triethylene glycol silicate) polymer.

A polyester containing 4 mols of glycerol, 2.5 mols of adipic acid and 0.5 mol of phthalic anhydride are mixed with tolylene diisocyanate in about equal proportions to produce a polyurethane prepolymer.

About 2 parts by weight of said polyurethane prepolymer and 1 part by weight of a catalyst mixture of triethylene glycol silicate and poly(triethylene glycol silicate) polymer, containing 20% water, 2% zinc stearate, 0.05% dimethyl ethanol amine and 0.5% paraffin oil, are mixed. The mixture is then agitated gently for 5 to 15 minutes until the mixture begins to expand. The mixture expands 8 to 10 times its original volume at ambient temperature and pressure, thereby producing a tough, rigid, fine cellular polyurethane product.

EXAMPLE XI

Polypropylene glycol having an average molecular weight of 450 to 500 is reacted with toluene diisocyanate in an NCO/OH molar ratio of about 2:1, thereby producing a liquid polyurethane prepolymer.

The said polyurethane prepolymer in the amount of 3 parts by weight were mixed with 3 parts by weight of poly(alpha-methyl styrene) polymer and 3 parts by weight of the mixture of an aqueous solution of propylene silicate and poly(prophylene silicate) polymer containing 20% water; then 1 part by weight of a liquid polysulfide polymer was added then mixed thoroughly and the mixture cures in a short period of time, thereby producing a white elastomer.

EXAMPLE XII

A polyurethane prepolymer, produced by the reaction of a liquid hydroxyl-terminated polybutadiene with 2,4-tolylene diisocyanate and which has a free NCO content of about 4% and an aqueous solution of triethylene glycol silicate and poly(triethylene glycol silicate) polymer as produced in Example X, containing 30% water, were mixed thoroughly and let stand for 12 to 24 hours, thereby producing an elastomer product. The product is further cured by heating at 70 degrees to 80 degrees C. for 3 to 4 hours. Mixed in the ratio of 3:1 by weight.

EXAMPLE XIII

A liquid polyester of the following composition: 16 moles of adipic acid, 16 moles of diethylene glycol, 1 mol of trimethylol propane, is reacted with toluene diisocyanate (80% 2,4-isomer and 2,6-isomer) in the ratio of 2 to 1 to produce a liquid polyurethane prepolymer. Two parts by weight of the polyurethane prepolymer are mixed with 1 part by weight of a catalytic mixture, an aqueous solution of propylene glycol silicate and poly(propylene glycol silicate) polymer containing 25% water, 0.01% stannous octoate, 0.02% triethylenediamine, 5% sulphanated castor oil, 2% ammonium oleate and 0.5% paraffin oil is added. The mixture is gently agitated for 5 to 15 minutes until the mixture begins to expand. The mixture expands 6 to 8 times its original volume, thereby producing a flexible foam. The product is further cured by heating at 70 degree to 80 degree C. for 3 to 4 hours.

EXAMPLE XIV

About 1 part by weight of a fine granular hydrated silica, 2 parts by weight of castor oil and 1% by weight of sodium hydroxide flakes are mixed when heated to just below the boiling temperature of castor oil while agitating at ambient pressure for 20 to 90 minutes, thereby producing a light brown castor oil silicate polymer.

About 1 part by weight of castor oil silicate polymer is mixed with 0.20 parts by weight of water containing 10% sodium dioctyl suffosuccinate and 1% stannous octoate, and the mixture is then mixed with 2 parts by weight of a polyurethane prepolymer containing 2 parts by weight of toluene diisocyanate (80% 2,4-isomer and 20% 2,6-isomer) and 1 part by weight of polyethylene glycol (450 to 500 molecular weight). The mixture is gently agitated at ambient pressure and temperature for 5 to 15 minutes until the mixture begins to expand. It is then poured into a mold, and the mixture expands 8 to 10 times its original volume, thereby producing a rigid, cream colored, polyurethane fine cellular product.

EXAMPLE XV

About 1 part by weight of the castor oil silicate polymer as produced in Example XIV and 1 part by weight of the polyurethane prepolymer as produced in Example XIV are mixed thoroughly at ambient temperature and pressure. A solid, cream colored polyurethane is produced in 1 to 4 hours.

EXAMPLE XVI

About 2 parts by weight of fine granular hydrated silica, 2 parts by weight of 2-ethyl-2(hydroxymethyl)-1,3-propanediol and 1% potassium hydroxide are mixed. The mixture is heated to just below the boiling point of the mixture while agitating at ambient pressure for 20 to 90 minutes, thereby producing tan granules of 2-ethyl-2(hydroxymethyl)-1,3-propanediol silicate and polymer. About 1 part by weight of said tan granules containing 30% water are added to 2 parts by weight of the polyurethane prepolymer as produced in Example XIV then agitated gently until it begins to expand. The mixture expands 8 to 10 times its original volume, thereby producing a cream colored, rigid, cellular product.

EXAMPLE XVII

About 1 part by weight of a fine granular hydrated silica, 2 parts by weight of granular cane sugar and 10% by weight of sodium carbonate are mixed. The mixture is heated to just above the melting temperature, but below the boiling temperature while agitating at ambient pressure for 20 to 90 minutes, thereby producing brown granules of sugar silicate polymer.

About 1 part by weight of the sugar silicate polymer and 1 part by weight of water are mixed then added to 4 parts by weight of the polyurethane prepolymer as produced in Example XIV. The mixture is gently agitated for 5 to 15 minutes until the mixture begins to expand. The mixture expands 8 to 10 times its original volume, thereby producing a rigid polyurethane fine cellular product.

EXAMPLE XVIII

About 1 part by weight of a fine granular hydrated silica, 2 parts by weight of ethanol and 10% by weight, percentage based on weight of the reactants, of sodium carbonate are mixed then heated to just below the boiling temperatures of ethanol while agitating for 20 to 90 minutes thereby producing a fine granular mixture of ethyl silicate and diethyl silicate.

About 1 part by weight of the mixture of ethyl silicate and diethyl silicate are mixed with 1 part by weight of glacial acetic acid then added to 4 parts by weight of the polyurethane prepolymer as produced in Example XIV. The mixture is gently agitated for 5 to 15 minutes until it begins to expand. The mixture expands 6 to 10 times its original volume, thereby producing a rigid, fine cellular polyurethane product.

EXAMPLE XIX

About 1 part by weight of a fine granular hydrated silica, 2 parts by weight of propanol and 5% by weight of potassium carbonate are mixed then heated to just below the boiling temperature of propanol while agitating at ambient pressure for 20 to 90 minutes, thereby producing a mixture of propanol silicate and dipropanol silicate.

About 1 part by weight of the mixture of propanol silicate and dipropanol silicate is mixed with 0.5 parts by weight of water then mixed with 2 parts by weight of the polyurethane prepolymer as produced in Example IV. The mixture is gently agitated for 5 to 15 minutes at ambient pressure and temperature until the mixture begins to expand. The mixture expands 6 to 10 times its original volume, thereby producing a tough fine, cellular semi-rigid product.

EXAMPLE XX

About 1 part by weight of a fine granular hydrated silica, 2 parts by weight of butanol and 10% by weight of sodium carbonate are mixed then heated in a closed system to just below the boiling temperature of the butanol while agitating at ambient pressure for 20 to 90 minutes, thereby producing a white, granular mixture of butanol silicate and dibutanol silicate.

About 1 part by weight of the mixture of butanol silicate and dibutanol silicate with 0.25 parts by weight of water are mixed with 1 part by weight of the polyurethane prepolymer as produced in Example I and 1 part by weight of the polyurethane prepolymer as produced in Example XIV. The mixture is gently agitated for 5 to 15 minutes until it begins to expand. It expands to about 8 to 12 times its original volume, thereby producing a rigid, fine cellular polyurethane product.

EXAMPLE XXI

About 1 part by weight of a fine granular hydrated silica, 2 parts by weight of isopropyl alcohol (70% alcohol with 30% water) and 10% by weight of sodium carbonate are mixed then heated in a closed system to just below the boiling temperature of the isopropyl alcohol while agitating at ambient pressure for 20 to 90 minutes, thereby producing a white granular mixture of isopropyl alcohol silicate and diisopropyl alcohol silicate.

About 1 part by weight of the mixture of isopropyl alcohol silicate and diisopropyl alcohol silicate containing about 20% by weight of water are mixed with 3 parts by weight of the polyurethane prepolymer as produced in Example I. The mixture is gently agitated for 5 to 15 minutes until it begins to expand. It expands 8 to 12 times its original volume, thereby producing a rigid, fine cellular polyurethane product.

The amount of polyurethane is reduced to only 0.5 parts by weight and then mixed in the same manner, thereby producing a solid, white polyurethane product.

EXAMPLE XXII

About 1 part by weight of fine granular hydrated silica, 3 parts by weight of caprylic alcohol and 10% by weight (percentage based on the weight of hydrated silica and caprylic alcohol of sodium carbonate are mixed then heated to just below the boiling temperature of caprylic alcohol while agitating at ambient pressure for 20 to 90 minutes, thereby producing a mixture of caprylic alcohol silicate and dicaprylic alcohol silicate.

About 1 part by weight of the mixture of caprylic alcohol silicate and dicaprylic silicate is mixed with 1 part by weight of water, containing 10% sodium dioctyl sulfosuccinate. The mixture is mixed with the polyurethane prepolymer as produced in Example XIII in the ratio of 1 to 2 parts by weight, then 0.5 part by weight of resinous extender, coal tar, is added. The mixture is gently agitated for 5 to 15 minutes at ambient pressure and temperature until the mixture begins to expand. The mixture expands 8 to 12 times its original volume thereby producing a semi-flexible fine cellular product.

Other monohydroxy compounds may be used in place of caprylic alcohol such as methyl alcohol, ethyl alcohol, propyl alcohol, isobutyl alcohol, amyl alcohol, hexyl alcohol, octyl alcohol, allyl alcohols, thioalcohols, phenols, cyclohexanol, methylcyclohexanol, benzyl alcohol, cyclohexanomethanol, methallylalcohol, cresols, thiophenols, thiocresols, halogenated alcohols and mixtures thereof.

EXAMPLE XXIII

About 1 part by weight of fine granular hydrated silica, 2 parts by weight of glycolic acid and 10% by weight of sodium carbonate are mixed then heated to just below the boiling temperature of glycolic acid while agitating at ambient pressure for 20 to 90 minutes, thereby producing a gray, granular mixture of glycolic acid silicate and poly (glycolic acid silicate) polymer.

One part by weight of the mixture of glycolic acid silicate and poly (glycolic acid silicate) polymer are mixed with 1 part by weight of water containing 10% sodium dioctyl sulfosuccinate and 3% soap. One part by weight of the catalytic mixture is added to 1 part by weight of the polyurethane prepolymer as produced in Example I and 1 part by weight of the polyurethane prepolymer as produced in Example XIII then gently agitating at ambient temperature and pressure for 5 to 10 minutes until the mixture begins to expand. The mixture expands 4 to 6 times its original volume, thereby producing a semiflexible, white in color, tough, polyurethane fine cellular product.

EXAMPLE XXIV

About 2 parts by weight of malic acid, 1 part by weight of fine granular hydrated silica and 5% by weight of potassium hydroxide are mixed then heated to just below the boiling temperature of malic acid while agitating at ambient pressure for 20 to 90 minutes, thereby producing a granular mixture of malic acid silicate and poly (malic acid silicate) polymer.

The mixture of malic acid silicate and poly (malic acid silicate) polymer is mixed with water in the ratio of 4 to 1 parts by weight then added to a polyurethane prepolymer, produced by reacting a trifunctional polypropylene glycol, having an average molecular weight of about 400, with tolylene diisocyanate to obtain a prepolymer having about 3% NCO groups, in the ratio of 1 to 2 parts by weight, then gently agitated at ambient pressure and temperature for 5 to 15 minutes until the mixture begins to expand, thereby producing a rigid, finely cellular, polyurethane product in 30 to 120 minutes.

Other suitable organic compounds containing hydroxyl and carboxylic radical may be used in place of malic acid such as 10 hydroxy undec