MXPA97007871A - Polyurethane pirorretardan foams - Google Patents

Abstract

The present invention relates to a flexible flame-retardant polyurethane foam containing the reaction product of: a) a polyoxyalkylene polyether polyol having an average equivalent weight of about 200 to about 2500, and b) an organic isocyanate, in the presence of c) a catalyst, a blowing agent, a surfactant, and d) optionally. a chain extender, this foam also contains: e) melamine in an amount in the range of about 10% by weight to about 55% by weight based on the weight of the foam, and f) an effective amount of a flame retardant auxiliary of melamine, where the organic isocyanate contains from about 70 to 85% by weight of diphenylmethane diisocyanate modified with carbodiimide-uretonimine and about 15 to 30% by weight of toluene diisocyanate, based on the weight of the isocyanate organic

Description

POLYURETHANE PIROREREATHERING FOAMS FIELD OF THE INVENTION The present invention pertains to flexible foams compositions, and in particular, to flexible polyurethane flame retardant foam compositions and methods for the preparation thereof. More particularly, the present invention relates to the preparation of flexible polyurethane flame retardant foam compositions containing an amount of melamine, preferably in the range from about 10% by weight to about 55% by weight of the total composition , together with an effective amount of an auxiliary flame retardant compound. The polyurethane foam product is prepared by reacting a polyoxyalkylene polyether polyol with an organic isocyanate, wherein the isocyanate comprises a mixture of toluene diisocyanate and carbodiimide-uretonimine-modified diphenylmethane diisocyanate.

BACKGROUND OF THE INVENTION The preparation of flexible polyurethane flame retardant foam compositions is generally well known, as well as proven by the prior art. U.S. Patent No. 4,022,718 teaches the preparation of cold-curing, high-resilience polyurethane foams that incorporate 2,3-dibromo-1,4-butanediol as a chain extender and flame retardant component. U.S. Patent No. 4,147,847 shows a method of preparing flame retardant polyurethane foams, flexible using specific foam stabilizers that reduce the necessary amount of the normal fire retardant additives. U.S. Patent No. 4,162,353 teaches the preparation of flexible polyurethane foams which incorporate therein a halo-substituted alkyl phosphate such as, for example, tris (2-chloroethyl) phosphate, such as, for example, (2-chloroethyl) phosphate. and an unsubstituted trialkyl phosphate, such as, for example, triethylphosphate. U.S. Patent 4,849,459, the disclosure of which is incorporated herein by reference, discloses a flexible, flame retardant polyurethane foam comprising the reaction product of a polyether polyol and a toluene diisocyanate that incorporates melamine and another flame retardant. These polyurethane foams present a significant fire retardant as presented by the foam products that pass the ASTM E162-81a Radiant Panel Test and the California 133. However, for certain applications it is necessary that a polyurethane foam exceeds the requirements of these tests and provide even higher fire retardancy.

For example, foam products that are used in the common transportation industry can provide flame propagation Index values below 25 with the ASTM D3675-90 flame test procedure. In this way, it remains a necessity, for polyurethane foam products, that exhibit high flame retardant capacity, to the extent that they can meet the severe flame propagation rates for transportation required by the ASTM flame test procedure. D3675-90, providing values for the flame propagation index below 25 in this test. Accordingly, the present invention relates to the preparation of flame retardant polyurethane foam compositions that provide flame propagation index values below 25 in the ASTM D3675-90 flame test procedure.

SUMMARY OF THE INVENTION The present invention is applied to flexible, high resilience polyurethane foam compositions and to conventional flexible polyurethane foam compositions that exhibit improved fire retardant capability. The polyurethane foams are prepared by reacting a polyoxyalkylene polyether polyol, having at least two active hydrogen atoms and an average equivalent weight from about 200 to about 2500, with an organic polyisocyanate in the presence of a catalyst, a blowing agent, a silicone surfactant and, optionally, a chain extender. The foam also contains melamine and an effective amount of another flame retardant compound. The organic isocyanate contains from about 70 to 85% by weight of diphenylmethane diisocyanate modified with carbodiimide-uretonimine and about 15 to 30% by weight of toluene diisocyanate, based on the weight of organic isocyanate. In an alternative embodiment of the present invention, a flexible flame retardant polyurethane foam contains a reaction product of: (a) a polyoxyalkylene polyether polyol having an average equivalent weight of about 200 about 2500, where it is dispersed, in situ in the polyether polyol, melamine in an amount ranging from about 10% by weight to about 55% by weight based on the weight of the foam and, (b) an organic isocyanate. The polyurethane foams are prepared by reacting the polyoxyalkylene polyether polyol with the organic polyisocyanate in the presence of (c) a catalyst, a blowing agent, a silicone surfactant and, optionally, (d) a chain extender. The foam compositions further contain (e) an effective amount of an auxiliary flame retardant other than melamine. The isocyanate contains from about 70 to 85 weight percent of diphenylmethane diisocyanate modified with carbodiimide-uretonimine and about 15 to 30% by weight of toluene diisocyanate, based on the weight of the organic diisocyanate, and the polyol of preference it consists of a dispersion in the polyol of the styrene-acrylonitrile graft polymer.

DETAILED DESCRIPTION OF THE INVENTION Unexpectedly it has been found that during the preparation of the flexible flame retardant polyurethane foams, a mixture of (a) melamine and (b) an effective amount of another flame retardant compound incorporated in a polyoxyalkylene polyether polyol when reacting with a particular mixture of organic isocyanates will result in a foam that will meet the requirements of the California Technical Bulletin 133. test. Most importantly, when this particular mixture of organic isocyanates is reacted with the polyoxyalkylene polyether, described below, to form a foam composition of the present invention, the flame propagation index values of less than 25 can be achieved according to the flame test procedure ASTM D3675-90. The polyurethane foams of the present invention contain melamine in the amount in the range of about 10 about 55% by weight, preferably from about 20 to about 40% by weight, most preferably from about 25 to about of 35% by weight of the total composition in combination with auxiliary flame retardants in the amount from about 1 to about 15% by weight, preferably from about 2 to about 10% by weight of the total composition. Suitable flame retardant compounds that can be used together with melamine are well known in the art and can include tri (2-chloroethyl) phosphate (Fyrol® CEF), tri (2-chlorosopropyl) phosphate (Fyrol® PCF), tri (3-) chlorosopropyl) phosphate (Fyrol® FR-2), pentabromodiphenyl oxide) DE60F®), chlorinated diphosphate ester (Antiblaze® 100), tris (2,3-dibromopropyl) -phosphate, tetrakis (2-chloroethyl) ethylene phosphate, oxide of pentabromodiphenyl, tris (1,3-dichlopropyl) phosphate, molybdenum trioxide, ammonium molybdate, ammonium phosphate, tricrecyl phosphate, 2,3-dibromopropanol, hexabromocyclododecane and dibromoethyldibromocyclohexane. Mixtures of the above auxiliary flame retardants can be used together with the melamine in the foam compositions of the present invention. The Fyrol® series of flame retardant compounds are commercially available from Akzo Nobel Chemicals Inc, of Dobbs Ferry, NY. DE60F® flame retardant compound is commercially available from Great Lakes Chemical Corporation of West Lafayette, IN. The flame retardant Antiblaze® 100 is available commercially from Albright & Silson from Richmond, VA. Representative polyols that can be employed in the preparation of flame retardant polyurethane foams are well known to those skilled in the art. These are usually prepared by the catalytic condensation of an alkylene oxide or mixture of alkylene oxides simultaneously or in sequence with an organic compound having at least two active hydrogen atoms, as shown in U.S. Patent Nos. 1,922,459; 3,190,927 and 3,346,557. Representative polyols include polyesters with polyhydroxyls, polyoxyalkylene polyether polyols, polyurethane polymers terminated with polyhydroxyls, phosphorus compounds containing polyhydroxyls and alkylene oxide addition products of polyhydric polydiesters, polyacetals, aliphatic polyols and thiols, ammonia and amines, including aromatic, aliphatic and heterocyclic amines, as well as mixtures thereof. The alkylene oxide addition products of the compounds containing two or more different groups within the above-defined class can also be used, for example, the amino alcohols containing an amino group and a hydroxyl group. Also, the alkylene oxide addition products of the compounds containing an SH group and an OH group as well as those containing an amino group and an SH group can be used. In general, the equivalent weight of polyols will vary from 100 to 10,000, preferably from 200 to 2500. Any of the suitable hydroxy terminal polyesters can be used, such as those prepared, for example, from polycarboxylic acids and polyhydric alcohols. Any of the suitable polycarboxylic acids can be used such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, acelaic acid, sebacic acid, brasilic acid, tapsic acid, maleic acid, fumaric acid, glutaconic acid, α-hydromuconic acid, α-hydromuconic acid [sic], α-butyl-α-ethylglutaric acid, α, β-diethyl-succinic acid, isophthalic acid, terephthalic acid, hemimellitic acid, and 1,4-cyclohexanedicarboxylic acid. Any suitable polyhydric alcohols, including aromatic and aliphatic alcohols, may be used as ethylene glycol, propylene glycol, trimethylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,4- pentanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, glycerol, 1,1,1-trimethylolpropane, 1,1-trimethylolethane, 1,2,6-hexanthrione, α-methyl glycoside, pentaerythritol and sorbitol. Also included within the term "polyhydric alcohol" are the phenol-derived compounds such as 2,2-bis (4-hydroxyphenyl) propane, commonly known as Bisphenol A. The hydroxyl-containing polyester can also be a polyester amide such as can be which is obtained by including some amine or aminoalcohol in the reagents for the preparation of the polyesters. In this way, the polyester amides can be obtained by condensing an amino alcohol such as ethanolamine with the polycarboxylic acids stated above or can be made using some components that make up the hydroxyl-containing polyester with only a portion of the components being a diamine such as ethylene diamine. . Any of the suitable polyoxyalkylene polyether polyols can be used as polymerization products of an alkylene oxide or a mixture of alkylene oxide with a polyhydric alcohol. Any of the suitable polyhydric alcohols can be used, such as those described above, for use in the preparation of the hydroxyl terminated polyesters. Any suitable alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, amylene oxide and mixtures of these oxides can be used. The polyoxyalkylene polyether polyols can be prepared from other starting materials such as tetrahydrofuran and mixtures of alkylene oxide-tetrahydrofuran; epihalohydrins such as epichlorohydrin; as well as the aralkylene oxides such as styrene oxide. The polyoxyalkylene polyether polyols may have primary or secondary hydroxyl groups. Polyether polyols include polyoxyethylene glycol, polyoxypropylene glycol, polyoxybutylene glycol, polytetramethylene glycol, block copolymers, for example, combinations of polyoxypropylene and polyoxyethylene glycols, poly-1,2-oxybutylene and polyoxyethylene glycols, poly-1,4-oxybutylene and polyoxyethylene glycols and glycols. random copolymers prepared from combinations of 2 or more alkylene oxides or by the sequential addition of 2 or more alkylene oxides. The polyoxyalkylene polyether polyols can be prepared by any of the known processes such as, for example, the process described by Wirtz in 1859 and in the Encyclopedia of Chemical Technology, Vol 7, pp. 257-262, published by Interscience Publishers, Inc., (1951) or in U.S. Patent No. 1,922,459. Preferred polyethers include the alkylene oxide addition products of trimethylolpropane, glycerin, pentaerythritol, sucrose, sorbitol, propylene glycol and 2 '(4,4'-hydroxyphenyl) propane and mixtures thereof, with equivalent weights from 100 to 10,000. Suitable polyhydric polythioethers which can be condensed with alkylene oxides include the condensation product of thiodiglycol or the reaction product of a dicarboxylic acid, as described above, for the preparation of the hydroxyl-containing polyesters with any other suitable thioether glycol. . The polyhydroxyl-containing phosphorus compounds which may be used include those compounds described in US Pat. No. 3,639,542. Preferred polyhydroxyl-containing phosphorus compounds are prepared from the alkylene oxides and the phosphorus acids having P2O5 equivalency from about 72% to about 95%. Suitable polyacetals which can be condensed with alkylene oxides include the reaction product of formaldehyde or other suitable aldehydes with a dihydric alcohol or an alkylene oxide, such as those described above. Suitable aliphatic thiols which can be condensed with alkylene oxides include the alkanethiols which contain one or more -SH groups such as 2-mercaptoethanol, 1,2-ethanedithiol, 1,2-propanedithiol, 1,3-propandithiol, and 1 , 6-hexandithiol; the alkene thiols such as 2-butene-1, 4-dithiol; and the alkyne thiols such as 3-hexyne-1, 6-dithiol. Suitable amines that can be condensed with alkylene oxides include the aromatic amines such as aniline, o-chloroaniline, p-aminoaniline, 1,5-diaminonaphthalene, methylenedianiline, the condensation products of aniline and formaldehyde and 2,3-, 2, 6-, 3,4-, 2,5- and 2,4-diaminotoluene; the amines such as methylamine, triisopropanolamine, ethylenediamine, 1,3-diaminopropane, 1,3-diaminobutane, 1,4-diaminobutane and ammonia. Also, polyols containing ester groups can be used in the present invention. These polyols are prepared by reacting the alkylene stannous oxide with an organic dicarboxylic acid anhydride and a compound containing reactive hydrogen atoms. A more extensive description of these polyols and their methods of preparation can be found in U.S. Patent Nos. 3,585,185; 3,639,541 and 3,639,542. Other polyols that can be employed have vinyl polymers incorporated therein. These polyols can be prepared (1) by means of the free radical polymerization, in situ, of an ethylenically unsaturated monomer or mixtures of monomers in a polyol, or (2) by dispersion in a polyol of a preformed graft polymer which is prepared by polymerization by free radicals in a solvent, as described in US Pat. Nos. 3,931,092; 4,014,846; 4,093,573 and 4,122,056, the descriptions of which are incorporated herein by reference, or (3) by low temperature polymerization in the presence of chain transfer agents. These polymerizations can be carried out at a temperature between 65 and 170 ° C, preferably between 75 and 135 ° C. Polyols that can be employed in the preparation of graft polymer dispersions are well known in the art. Conventional polyols essentially free of ethylenic unsaturation, such as those described in republished US Patent No. 28,715 and unsaturated polyols such as those described in US Pat. No. 3,652,659 and republished No. 29,014 can be used for the preparation of the graft polymer dispersions used in the present invention, the descriptions of which are incorporated by reference. The polyurethane foams that are employed in the present invention are generally prepared by the reaction of a polyoxyalkylene polyether polyol with an organic polyisocyanate in the presence of a blowing agent and, optionally, in the presence of additional polyhydroxy containing components, extenders. of chain, catalysts, surface active agents, stabilizers, colorants, fillers and pigments. Suitable processes for the preparation of cellular polyurethane foams are described in U.S. Patent No. Re.24, 514, the description of which is incorporated herein by reference, together with the suitable machinery used for this process. When water is added as a blowing agent, the corresponding amounts of the excess isocyanate can be used for the reaction with the water and produce carbon dioxide. It is possible to continue with the preparation of the polyurethane foams by a prepolymer technique in which an excess of organic polyisocyanate is reacted, in a first step, with the polyol of the present invention to prepare a prepolymer with free isocyanate groups, which in turn they are reacted in a second step with water and / or additional polyol to prepare a foam. Alternatively, the components can be reacted in a single working step commonly known as the "one shot" polyurethane preparation technique. In addition, instead of water, blowing agents such as low-boiling hydrocarbons such as pentane, hexane, hepatane, pentene and heptene can be used; azo compounds such as azohydrobencendinitrile; halogenated hydrocarbons such as dichlorofluoromethane, trichlorofluoromethane, dichlorofluoroethane, vinylidene chloride and methylene chloride. A first organic polyisocyanate which is used in the present invention is a toluene di- orcyanate. Representative toluene diisocyanates include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate and mixtures of 2,4- and 2,6-toluene diisocyanate. A preferred toluene diisocyanate is a mixture of 80% by weight of 2,4-toluene diisocyanate and 20% by weight of 2,6-toluene diisocyanate. A second organic isocyanate used in the present invention includes a diphenylmethane diisocyanate modified with carbodiimide-uretonimine. The structure of the carbodiimide and uretonimine are shown below. O = C = N-R-NC0 + or = C = N-R-N = C = N- -NCO ^ == S-- The carbodiimide-uretonimine modified diphenylmethane diisocyanate of the present invention can be prepared using the carbodiimide promoter compounds well known as catalysts. The carbodiimide catalysts that are employed in accordance with the present invention can be any of those known in the art to be useful in the conversion of an isocyanate to the corresponding carbodiimide. U.S. Patent 4,743,626, the disclosure of which is incorporated herein by reference, discloses suitable catalysts which are useful herein. Preferred catalysts include the 1-oxides and 1-sulfides of phospholene having the formulas: wherein a, b, c and d are each selected from the group consisting of hydrogen and hydrocarbyls of 1 to 12 carbon atoms inclusive, R is selected from the group consisting of alkyl and lower aryl and X is selected from the group consisting of oxygen and sulfur. The aforementioned phospholene compounds and methods for their preparation are described in U.S. Patent Nos. 2,663,737; 2,663,738; and 2,853,473. The 3-phospholenes can be easily isomerized to the corresponding 2-phospholenes of a heat treatment or by refluxing with an aqueous base, as described in Quinn et al., Journal American Chemical Society, 33, 1024, 1968. Representative compounds within the aforementioned class are 1-phenyl-2-phospholene oxide; 1-Oxide of 3-methyl-l-phenyl-2-phospholene; 1-phenyl-2-phospholene sulfide; 1-ethyl-phospholene 1-oxide; 1-ethyl-3-methyl-2-phospholene 1-oxide; 1-Sulfide of l-ethyl-3-methyl-2-phospholene and the isomeric phospholenes corresponding to the aforementioned compounds. Also, phospholene oxides bound to the polymer, specifically those having recurring units, for example, can be employed. as described in U.S. Patent No. 4,105,643, as well as those having the following structure as described in U.S. Patent No. 4,105,642: Other suitable catalysts are set forth in the aforementioned U.S. Patent No. 4,743,626. The temperature ranges that can be used for the carbodiimide-uretonimine formation reactions are in the range of 50 to 250 ° C and preferably of 60 to 230 ° C. The reaction product can be treated at the reaction temperature, or lower, with catalyst deactivators including salts such as magnesium chloride dihydrate, acid chlorides such as benzoyl chlorides and acetyl chlorides, acids such as hydrochloric acid, oxalic acid, phosphoric acid , benzenesulfonic acid, toluenesulfonic acid, methanesulfonic acid or trifluoromethanesulfonic acid, sulfonyl chlorides such as benzenesulfonyl chloride, toluenesulfonyl chloride and the like. The deactivators that may be employed are the agents such as dimethyl sulfate, or alkyl phenyl toluene sulfonates, ethyl chloride and similar compounds as described in US Pat. No. 3,769,318.

The organic isocyanate of the present invention consists of a combination of diphenylmethane diisocyanate modified with carbodiimide-uretonimine and toluene diisocyanate. The carbodiimide-uretonimine-modified diphenylmethane diisocyanate is present in an amount of about 70 to 85% by weight, preferably from about 75 to 80% by weight, based on the weight of the organic isocyanate. The toluene diisocyanate is present in the combination of the organic isocyanate in an amount from about 15 to about 30% by weight, preferably from about 20 to 25% by weight based on the weight of the organic isocyanate. Limited amounts of other organic isocyanates may be included in the isocyanate mixture which is reacted with the polyether polyol to produce the polyurethane foams of the present invention. For example, impure polyisocyanates such as impure toluene diisocyanate which is obtained by phosgenation of a mixture of toluene diamines or impure diphenylmethane isocyanate which is obtained by phosgenation of impure diphenylmethanediamine, can be included in the isocyanate combination. Preferred impure isocyanates are described in U.S. Patent No. 3,215,652. Other isocyanates that can be incorporated into the organic polyisocyanate combination include hexamethylene diisocyanate, tetramethylene diisocyanate, cyclohexane 1,4-diisocyanate, hexahydrotoluene diisocyanate (and its isomers), naphthalene-1,5-diisocyanate, 2,4-diisocyanate of 1-ethoxyphenyl, 4,4'-diphenylmethane diisocyanate, 4,4'-diiphenylene-diphenylene, 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyl-4,4-diisocyanate '-biphenyl and 3, 3' dimethyldiphenylmethane-4,4'-diisocyanate; the triisocyanates such as 4,4 ', 4", 4" -triphenylmethane triisocyanate and toluene 2,4,6-triisocyanate; and tetraisocyanates such as 2, 2'-5, 5'-tetraisocyanate of 4,4'-dimethylphenylmethane and polymeric polyisocyanates such as polymethylene polyphenylene polyisocyanate. However, when these auxiliary isocyanates are included in the isocyanate mixture, they generally do not comprise more than about 15% by weight based on the organic isocyanate. Chain extender agents that can be employed in the preparation of polyurethane foams include those compounds having at least two functional groups that carry active hydrogen atoms such as water, hydrazine, primary and secondary diamines, amino alcohols, amino acids, hydroxy acids glycols or mixtures thereof. A preferred group of chain extenders includes water, ethylene glycol, 1-butane diol, and primary and secondary amines that react more easily than water with the prepolymer, such as phenylenediamine, 1,4-cyclohexane-bis (methylamino) ), ethylenediamine, diethylenetriamine, N- (2-hydroxypropyl) -ethylenediamine, N, N '-di (2-hydroxypropyl) ethylenediamine, piperazine and 2-methylpiperazine. Any suitable catalyst including tertiary amines can be used, such as, for example, triethylenediamine, N-methylmorpholine, N-ethylmorpholine, diethylethanolamine, N-co-morpholine, l-methyl-4-dimethylaminoethylpiperazine, 3-methoxyaminopropylenediethylamine, N, N, N '- trimethylisopropylpropylideneamine, 3-diethylaminopropylenamine, dimethylbenzylamine and the like. Other suitable catalysts are, for example, stannous chloride, butyltin di-2-diethylhexanoate, stannous oxide, as well as other organometallic compounds as described in U.S. Patent No. 2,846,408. In general, an active surface agent is required for the production of the higher grade polyurethane foam, according to the present invention, since in the absence thereof, the foams collapse or contain very large irregular cells. Numerous surface active agents have been found satisfactory. Preferred are nonionic surface active agents. Of these, nonionic surface active agents such as well-known silicones have been found particularly desirable. Other surface active agents which may function, alth not preferred, include polyethylene glycol ethers of long chain alcohols, tertiary amines or alkanolamine salts of long chain alkyl esters of acid sulfate, alkylsulfonic esters and alkyl arylsulfonic acids. The polyurethane foams of the present invention exhibit flame propagation index values of less than 25 under flame test procedure ASTM D3675-90. This test, well known to those skilled in the art, measures the surface flammability of flexible cellular materials using a source of radiant heat energy. A flame propagation rating is assigned to a given application when it is determined by the regulatory body that complies with the inspection. For example, the New York / New Jersey port authority requires records of the flame propagation index measured by ASTM D3675-90 of less than 100 in the cushioning materials used in upholstered furniture applications. In this way, the foam compositions of the present invention provide sufficient fire retardant capacity for most applications, including those requiring unusual high levels of slow combustion such as those required for seating applications for mass transit. The following examples are offered to illustrate the general nature of the invention. Those skilled in the art will appreciate that they are not limiting the scope of the spirit of the invention and that various and obvious modifications can be made by those skilled in the art. All the parts are by weight unless otherwise stated. The following materials were used in the examples: Polyol A is a graft polyol of an addition product of propylene oxide / ethylene oxide of glycerin containing from 5 to 25% by weight of ethylene oxide in situ with 1 to 50% by weight of graft dispersion ethylene acrylonitrile. The polyol B is a polyether polyol of the addition product propylene oxide / ethylene glycerin oxide containing from 5 to 25% by weight of ethylene oxide with a hydroxyl number of from 10 to 60. DEOA is diethanolamine. CD-5164 is a silicone surfactant manufactured by AIR PRODUCTS. Catalyst A is a 3/1 mixture of DABCO® 33LV catalyst (AIR PRODUCTS).

And the NIAX® A-l (Union Carbide) catalyst. Catalyst B is the catalyst DABCO® T-12 (AIR PRODUCTS). Fyrol® FR-2 is a tri (1,3-dichloroisopropyl) phosphate manufactured by AKZO Chemical. TDI is toluene diisocyanate. Isocyanate A is a mixture of 77.5% by weight of diphenylmethane diisocyanate modified with carbodiimide-uretonimine and 22.5% by weight of toluene diisocyanate.

Examples 1-4 Examples 1-4 were prepared on a Hennecke UBT-63 machine using the following procedure: A resin mixture composed of polyols A and B, melamine, pigment and 1/3 DEOALF in the proportions listed, was load in a 120-gallon tank equipped with a blade turbine agitator rotating 60 rpm and stirred for 24 hours at 90 ° F after passing through a highly shear in-line mixer prior to foaming. This polyol / melamine suspension and the other urethane components are dosed in separate streams in a low pressure casting channel with a spigot mixer rotating at 5400 rpm. Then, the reaction mixture is replaced with a mobile conveyor. The distributed liquid mixture begins to accrete, then expands, is shaped by the moving conveyor and the static side walls. This continuous foaming operation of the reaction is allowed to run to a block length of 15 feet from the formed foam. The foam expands to its full height in approximately 3 minutes. The foam block is then allowed to harden for a minimum of 72 hours under ambient conditions after which standard test pads are cut to verify physical property. In the examples, the physical properties of the polyurethane foam are determined by the standard test methods ASTMD 3574-91 for Flexible Cellular Materials - Urethane Foams in Plaque, Agglomerated and Molded. Additional tests include the California Technical Bulletin 117 Test, the California Technical Bulletin 133 Test, British Standard 5852 part 2: copy 5, and the ASTM D3675-90 Radiant Panel test. Table 1 Examples 1 2 3 4 PHYSICAL PROPERTIES Density, PCF 3.01 5.20 2.72 5.15 Ductility, PSI 14.9 14.5 10.8 11.8 Elongation,% 140 120 137 130 Tear, Pl 1.7 1.6 1.8 1.9 Resilience,% 52 59 54 66 IFD, lbs / 50 in. quad (4 in) 25% 26.6 36.4 26.0 39.1 65% 78.8 124.3 64.1 128.5 Support factor 2.91 3.42 2.40 3.29 Wet Aging 3h to 220F CFD, percent 8.7 76 102 84 of the original 50% Series of 26 9 13 10 compression,% Series 75% Airflow, 0.5 0.8 0.8 1.2 CFM PROPERTIES OF FLAMABILITY * MVSS-302 passes raisin passes Open flame passes raisin passes Cal. T. B. 117 Cigarro Cal. T. pasa pasa pasa pasa B. 117 Flame without smoke% weight withheld 99.9 99.8 99.5 99.7 (min.80%) BS5852 Pt 2 copy passes raisin passes ** (FR polyester fabric) Time 2:45 3:48 6:27 4:57 flame extinction, min: sec Weight loss, g 26.6 18.4 22.0 22.2 Cal. T. B. 173 raisin passes pasa pasa c *** Loss weight, lbs 1.7 0.1 0.1 0.2 Radiant panel ASTMD3675 index 10 7 67 30 flame spread * This numerical classification of the spread of the flame, as in other flammability tests, does not reflect the risks presented by this or any other material under real fire conditions. ** average of two combustions. *** Cushioned chairs covered with 55% / 45% wool / nylon fabric.

Claims (16)

1. CLAIMS A flexible flame retardant polyurethane foam containing the reaction product of: (a) a polyoxyalkylene polyether polyol having an average equivalent weight of about 200 to about 2500, and (b) an organic isocyanate, in the presence of (c) a catalyst, a blowing agent, a surfactant, and (d) optionally, a chain extender, this foam further contains: (e) melamine in an amount in the range of about 10% by weight to about 55% by weight based on the weight of the foam, and (f) an effective amount of an auxiliary flame retardant other than melamine, wherein the organic isocyanate contains from about 70 to 85% by weight of diphenylmethane diisocyanate modified with carbodiimide-uretonimine and about 15 to 30% by weight of toluene diisocyanate, based on the weight of the organic isocyanate.
2. The foam, as mentioned in claim 1, wherein the auxiliary flame retardant is employed in an amount in the range of about 1% by weight to about 15% by weight of the total composition.
3. The foam, as mentioned in claim 1, wherein the polyether polyol is a combination of a propylene oxide, the addition product of the ethylene oxide of glycerin containing about 5 to 25% by weight of ethylene oxide. and a propylene oxide addition product of propylene glycol containing about 1 to 50% by weight of the styrene acrylonitrile graft dispersion.
4. The foam, as mentioned in claim 3, wherein the glycerin based on polyols is about 10 to 95% by weight of the polyol mixture.
5. The foam, as mentioned in claim 1, wherein the amount of melamine ranges from about 25 to about 35% by weight of the total composition.
6. The foam, as mentioned in claim 1, wherein the flame retardant is selected from the group consisting of Fyrol® CEF (tri (2-chloroethyl) phosphate), Fyrol® PCF tri (2-chlorosopropyl) phosphate, Fyrol® FR-2 tri (1,3-dichloroisopropyl) phosphate, DE60F® (pentabromodiphenyl oxide), Antiblaze® 100 (chlorinated diphosphate ester) and mixtures thereof.
7. The foam, as mentioned in claim 1, wherein the foam is a high resilience foam.
8. A flexible flame retardant polyurethane containing the reaction product of (a) a polyoxyalkylene polyether polyol having an average equivalent weight of about 200 to about 2500, where it disperses, in situ, within the polyether polyol is melamine in an amount in the range of about 10% by weight to about 55% by weight based on the weight of the foam; and (b) an organic isocyanate; (c) in the presence of a catalyst, a blowing agent, a silicone surfactant; and (d) optionally a chain extender; and (e) an effective amount of an oxidizing flame retardant other than melamine, wherein the polyol contains a dispersion in the polyol of the styrene-acrylonitrile graft polymer and the isocyanate consists of about 70 to 85% by weight of the carbodiimide-modified diphenylmethane diisocyanate. -tonthyimine and about 15 to 30% by weight of toluene diisocyanate based on the weight of the organic isocyanate.
9. The foam, as mentioned in claim 8, wherein the dispersion in the polyol of the graft polymer is prepared by the free radical polymerization, in situ, of an ethylenically unsaturated monomer or mixture of monomers in a polyol.
10. 10. The foam, as mentioned in claim 8, wherein the polymer dispersion is prepared by dispersing a preformed graft polymer in a polyol.
11. The foam, as mentioned in claim 8, wherein the polyol contains a mixture of at least one conventional polyether polyol and at least one dispersion of the graft polymer in the polyol.
12. The foam, as mentioned in claim 8, wherein the auxiliary flame retardant is employed in an amount in the range of from about 2 to about 10% by weight of the total composition and the amount of melamine in the range of about 25 to about 35% by weight of the total composition.
13. 13. The foam, as mentioned in claim 8, wherein the foam is a high resilience foam.
14. 14. A flexible flame retardant polyurethane foam containing the reaction product of: (a) a polyoxyalkylene polyether polyol having an average equivalent weight of about 200 to about 2500, and (b) an organic isocyanate consisting of about 70 to 85% by weight of carbodiimide-uretonimine-modified diphenylmethane diisocyanate and about 15 to 30% by weight of toluene disisocyanate, based on the weight of the organic isocyanate, in the presence of: (c) a catalyst, an agent of blowing, a surfactant, and (d) optionally a chain extender, this foam further contains: (e) melamine in the amount in the range of about 20% by weight to about 40% by weight based on weight of the foam, and (f) an auxiliary flame retardant other than melamine in an amount in the range from about 1 to about 15% by weight based on the weight of the foam; wherein the foam exhibits flame propagation index values of less than about 25, in accordance with the ASTM D3675-90 flame test procedure.
15. 15. The foam, as claimed in claim 14, wherein the polyether polyol is a combination of propylene oxide, the addition product of the ethylene oxide containing about 5 to 25% by weight of ethylene oxide and a Addition product of propylene oxide of propylene glycol containing about 1 to 50% by weight of the dispersion of the styrene-acrylonitrile graft.
16. 16. The foam, as recited in claim 14, wherein the glycerin based on polyols is about 10 to 95% by weight of the polyol mixture. The foam, as mentioned in claim 16, wherein the melamine is in the range from about 25 to 35% by weight of the total composition. The foam, as mentioned in claim 14, wherein the flame retardant is selected from the group consisting of Fyrol® CEF (tri (2-chloroethyl) phosphate), Fyrol® PCF (tri (2-chlorosopropyl) phosphate, Fyrol® FR-2 (tri (1,3-dichloroisopropyl) phosphate, DE60F® (pentabromodiphenyl oxide), Antiblaze® 100 (chlorinated diphosphate ester) and mixtures thereof The foam, as mentioned in claim 14, wherein the melamine is dispersed in situ within the polyether polyol in an amount ranging from about 25% by weight to about 35% by weight based on the weight of the foam.The foam, as mentioned in claim 14, where the foam is a high resilience foam.