DE10047024A1 - Production of fireproof flexible polyurethane foam for use in cushions, involves reacting polyisocyanate with a special polyether-ol mixture, blowing agents and other components, using melamine as fire retardant - Google Patents

Abstract

Fireproof flexible polyurethane foam is made from a mixture of polyether-ol(s) with an OH number (OHN) of 20-80 and a primary OH group content (OHC) of more than 70%, based on 2-4C alkylene oxides with an ethylene oxide content of less than 25 wt.%, and similar compound(s) with an OHN of more than 30 and an OHC of less than 70%, using melamine as fire retardant. A method for the production of fire-resistant, flexible polyurethane foam by reacting optionally modified polyisocyanates (a) with a polyether-ol mixture (b) and optionally other isocyanate-reactive compounds (c) in presence of water and/or other blowing agents (d), catalysts (e), stabilisers (f), fire retardants (g) and optionally other additives etc. (h). In this method, component (b) comprises (b1) at least difunctional polyether-ol(s) with an OH number of 20-80 mg KOH/g and a prim. OH group content of more than 70%, based on propylene oxide and/or butylene oxide and ethylene oxide (EO), with an EO content of less than 25 wt% based on total alkylene oxide and (b2) polyether-ol(s) based on the same components as in (b1), with an OH number of more than 30 and a prim. OH content of less than 70%, and component (g) comprises melamine, optionally with other fire retardants. An Independent claim is also included for flexible polyurethane foam obtained by this method.

Description

The production of polyurethane foams by implementation of organic and / or modified organic poly isocyanates or prepolymers with higher functional ver bonds with at least two reactive hydrogen atoms, for example polyoxyalkylene polyamines and / or preferably organic polyhydroxyl compounds, especially polyetherols, with molecular weights of 300 to 6000, and optionally Chain extenders and / or crosslinking agents with molecular weight up to approx. 400 in the presence of catalysts, propellants agents, flame retardants, auxiliaries and / or additives is known and has been described many times. A summary Overview of the manufacture of polyurethane foams z. B. in the plastic manual, volume. VII, "Polyurethane", 1st edition 1966, published by Dr. R. Vieweg and Dr. A. Höchtlen as well 2nd edition, 1983, and 3rd edition, 1993, each published from Dr. G. Oertel (Carl Hanser Verlag, Munich).

For numerous areas of application, it is often necessary To provide polyurethane foams with flame retardants to a To minimize the risk of fire of such materials. Besides there oblong known halogen-containing flame retardants, which ins Melamine is particularly undesirable for ecological reasons an especially suitable one for flexible foams and widely used flame retardant. It succeeds in many cases, flame protection in accordance with the Crib-V standard fulfill.

So in EP-A-0422797 a combination of melamine and poly urea polyols used for flame protection in flexible foam. In EP-A-0439719 in addition to melamine and. a. Cyanuric acid derivatives for uses flame protection. EP-A-0642543 refers to that especially when using melamine a remarkable Foam softening is evident for our application purposes is considered unfavorable. In EP-A-482 507 as Flame retardant a combination of expanded graphite, melamine and Ammonium polyphosphate described. Expandable graphite is used here preferably to prevent the melamine from settling. As special Expandable graphite with a grain size of <0.5 mm is therefore preferred proposed. With such a small grain size, however  Bloating effect on which the flame retardant effect of the expanded graphite based, too low.

CA 2203730 tries to provide the required flame protection in soft foams by introducing PVC paste into the To realize PUR mixture. Considerable proportions needed. WO-A-9823678 describes the use of melamine and red phosphorus, which in this case is a hard integral foams of higher density. Both flame retardants are said to result in an improved effect, with flame protection in higher density range is usually easier to implement. DE-A-37 32 238 is oriented in the manufacture of flame retardants possible PUR foams to impregnate the foam with Polychloroprene and aluminum hydroxide, which is a complex Ver driving represents. A use of halogenated phosphonate esters based on dibromo neopentyl glycol are said according to DE-A-21 66 942 lead to flame retardant PUR foams. In EP-A-835905 is described the preparation of stable melamine dispersions. According to the specified teaching, flame protection up to Realize stage Crib V.

US-A-5177118 discloses special prepolymers with an NCO content from 2 to 15 wt% described the positive effects should have flame protection.

According to US 5506278, PHD polyols in combination with melamine flame-retardant PUR flexible foams result. In a similar way in DE-A-35 30 519 called a flame retardant foam, which in addition Melamine as a basic flame retardant, especially a polymer polyol includes.

To achieve a flame retardant foam is often on Expanded graphite used. EP-A-337228 describes polyurethane foams whose polyol components are polyester alcohols and which as a flame retardant is a mixture of expanded graphite and Ammonium phosphate, calcium carbonate, calcium cyanamide or aluminum contain oxide hydrate. The polyurethanes described there have however poor fire behavior. In EP-A-358 985 describes polyurethanes that are used as flame retardants in addition Expandable graphite also ammonium polyphosphate, calcium cyanamide, aluminum contain oxide hydrate or calcium carbonate and in their manufacture position polyurea-polyol dispersions were used. EP-A-414 868 describes polyurethanes used as flame retardants Expandable graphite containing a grain size in the range between 0.3 and 1 mm and in the cell webs of the polyurethane foam is installed.  

Allow the inventions listed in the prior art definitely the production of flame retardant polyurethane flexible foams that meet the Crib V test in particular, whereby there is still a considerable ver potential for improvement with regard to achieving the Crib VII Tests and the processability of such formulations exist.

The object of the invention was to provide a method for producing flame retardant flexible polyurethane foams (Crib VII) wrap, where by the polyol combination used especially the decomposition behavior of the foams during the fire process changed positively and thereby a better one Effect of the flame retardant is realized.

Surprisingly, the object was achieved in that a special polyol combination consisting of

• 1. at least one at least two-functional polyetherol based on propylene oxide and / or butylene oxide and Ethylene oxide, the proportion of ethylene oxide based on the total amount of alkylene oxide used, less than 25 wt .-%, with an OH number of 20 to 80 mg KOH / g and a proportion of primary OH groups greater than 70% and
• 2. at least one polyetherol based on propylene oxide and / or butylene oxide and ethylene oxide with an OH number of greater than 30 mg KOH / g and a proportion of primary OH groups less than 70%,

in connection with melamine and other flame retardants Is used.

The invention accordingly relates to a process for the production of flame-retardant flexible polyurethane foams by reacting organic and / or modified organic polyisocyanates (a) with a polyether mixture (b) and, if appropriate, further compounds (c) having isocyanate-reactive hydrogen atoms in the presence of water and / or other blowing agents (d), catalysts (e), stabilizers (f), flame retardants (g) and optionally other auxiliaries and additives (h), which is characterized in that the polyether mixture (b) consists of

• 1. at least one at least two-functional polyetherol based on propylene oxide and / or butylene oxide and Ethylene oxide, the proportion of ethylene oxide based on the total amount of alkylene oxide used, less than 25% by weight is, with an OH number of 20 to 80 mg KOH / g and one Proportion of primary OH groups greater than 70% and
• 2. at least one polyetherol based on propylene oxide and / or butylene oxide and ethylene oxide with an OH number of greater than 30 mg KOH / g and a proportion of primary OH groups less than 70%

and as a flame retardant (g) melamine, optionally in a mixture with other flame retardants.

Objects of the invention are also those according to this Ver drive manufactured flame-retardant flexible polyurethane foam fabrics and their use as upholstery for furniture and vehicles sit.

We surprisingly found in our research that by using the combination of polyols according to the invention (b) the fire behavior of flexible polyurethane foams so affected can be flowed that the Crib VII test is passed. Surprisingly, due to the modified soft phase, resulting from the polyol mixture according to the invention, open obviously a reduction in the phase transition of the decomposition products can be reached in the gas phase.

The following is to be stated about the components used in the polyol mixture according to the invention:
The component (b1) consists of at least one at least two-functional polyetherol based on propylene oxide and / or butylene oxide and ethylene oxide, the ethylene oxide proportion, based on the total amount of alkylene oxide used, being less than 25% by weight. The OH number of these polyetherols is 20 to 80 mg KOH / g. They have a proportion of primary OH groups greater than 70%.

For example, the following are suitable as (b1): polyetherols, based on glycerin, trimethylolpropane or sorbitol as Starter. They show due to the ethylene oxide end block mainly primary OH groups. Polyethers are preferred ole with glycerol or trimethylolpropane, particularly preferred used with glycerin as a starter.  

The component (b2) consists of at least one polyetherol based on propylene oxide and / or butylene oxide and ethylene oxide with an OH number of greater than 30 mg KOH / g and a proportion at primary OH groups less than 70%.

Examples include: polyetherols with Water, propylene glycol or glycerin as a starter. Prefers are polyols with an OH number of 50 to 80 mg KOH / g ver applies.

The weight ratio of component (b1) to component (b2) is advantageously more than 0.3, preferably more than 1.0.

The polyetherols mentioned are by known methods, such as they are, for example, described below.

The flame-retardant polyurethane soft according to the invention foams are made by converting organic and / or modified organic polyisocyanates (a) with the above described polyether mixture (b) and optionally further having hydrogen atoms reactive towards isocyanates Compounds (c) in the presence of water and / or other blowing agents agents (d), catalysts (e) stabilizers (f), flame retardants agents (g) and, where appropriate, other auxiliaries and additives (h) made.

The following must be carried out in detail for the other starting components that can be used:
Suitable organic polyisocyanates (a) for the production of the polyurethanes according to the invention are the aliphatic, cycloaliphatic araliphatic and preferably aromatic polyvalent isocyanates known per se.

The following may be mentioned as examples: alkylene diisocyanates with 4 to 12 carbon atoms in the alkylene radical such as 1,12-dodecane diisocyanate, 2-ethyl-tetramethylene diisocyanate-1,4,2-methylpenta methylene diisocyanate 1,5, tetramethylene diisocyanate 1,4 and before preferably 1,6-hexamethylene diisocyanate; cycloaliphatic diiso cyanates, such as cyclohexane-1,3- and -1,4-diisocyanate and any Mixtures of these isomers, 1-isocyanato-3,3,5-trimethyl-5-iso cyanatomethylcyclohexane (IPDI), 2,4- and 2,6-hexahydrotoluylene diisocyanate and the corresponding isomer mixtures, 4,4'-, 2,2'- and 2,4'-dicyclohexylmethane diisocyanate and the ent speaking isomer mixtures, and preferably aromatic di- and polyisocyanates, such as. B. 2,4- and 2,6-tolylene diisocyanate and  the corresponding mixtures of isomers, 4,4'-, 2,4'- and 2,2'-di phenylmethane diisocyanate and the corresponding mixtures of isomers, Mixtures of 4,4'- and 2,2'-diphenylmethane diisocyanates, poly phenylpolymethylene polyisocyanates, mixtures of 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanates and polyphenylpolymethylene poly isocyanates (raw MDI) and mixtures of raw MDI and toluene diisocyanates. The organic di- and polyisocyanates can individually or in the form of their mixtures. Prefers Toluene diisocyanate, mixtures of diphenyl are used methane diisocyanate isomers, mixtures of diphenylmethane diiso cyanate and crude MDI or tolylene diisocyanate with diphenylmethane diisocyanate and / or raw MDI. Particularly preferably used are mixtures of diphenylmethane diisocyanate isomers with Proportions of 2,4'-diphenylmethane diisocyanate of at least 10% by weight.

So-called modified polyvalent iso are also common cyanate, d. H. Products made by chemical conversion of organic Di- and / or polyisocyanates are obtained used. example ester, urea, biuret, allophanate, Carbodiimide, isocyanurate, uretdione and / or urethane groups containing di- and / or polyisocyanates. In detail come with for example into consideration: reaction products of urethane groups containing organic, preferably aromatic, polyiso cyanates with NCO contents of 43 to 15% by weight, preferably from 31 to 21 wt .-%, based on the total weight, for example wise with low molecular weight diols, triplets, dialkylene glycols, Trialkylene glycols or molecular polyoxyalkylene glycols weights up to 6000, in particular with molecular weights up to 1500, modified 4,4'-diphenylmethane diisocyanate, modified 4,4'- and 2,4'-diphenylmethane diisocyanate mixtures or modified Raw MDI or 2,4- or 2,6-tolylene diisocyanate. The Di or Polyoxyalkylene glycols can be used individually or as mixtures are used, for example: diethylene, di propylene glycol, polyoxyethylene, polyoxypropylene and polyoxy propylene polyoxyethylene glycols, triols and / or tetrols. Suitable are also prepolymers containing NCO groups with NCO contents from 25 to 3.5% by weight, preferably from 21 to 14% by weight, based on the total weight, made from the following described polyester and / or preferably polyether polyols and 4,4'-diphenylmethane diisocyanate, mixtures of 2,4'- and 4,4'-diphenylmethane diisocyanate, 2,4- and / or 2,6-tolylene diiso cyanates or raw MDI. Liquid, Polyiso containing carbodiimide groups and / or isocyanurate rings cyanates with NCO contents of 43 to 15, preferably 31 to 21% by weight, based on the total weight, e.g. B. based on 4,4'-, 2,4'- and / or 2,2'-diphenylmethane diisocyanate and / or 2,4  and / or 2,6-tolylene diisocyanate. The modified Polyiso cyanates can be used together or with unmodified organic Polyisocyanates such as B. 2,4'-, 4,4'-diphenylmethane diisocyanate, Raw MDI, 2,4- and / or 2,6-tolylene diisocyanate can be mixed.

Have proven particularly useful as modified organic poly Isocyanate NCO group-containing prepolymers, which advantageously are formed from the reaction of the isocyanates (a) with the poly etherols (b) and optionally compounds of the components (c) and / or (d).

In addition to the poly used according to the invention described above ether mixture (b) are optionally more than iso Compounds containing cyanate-reactive hydrogen atoms (c) added.

For this, there are primarily connections with at least two reactive hydrogen atoms in question. This will be more appropriate as those with a functionality of 2 to 8, preferably 2 to 3, and an average molecular weight of 300 to 8000, preferably from 300 to 5000 used.

Polyols with a functionality of 2 to 8, preferably 2 to 3, and an average molecular weight from 300 to 8000, preferably from 300 to 5000. The The hydroxyl number of the polyhydroxyl compounds is in all Rule 20 to 800 and preferably 20 to 100.

The polyether polyols used in components (b) and (c) are by known methods, for example by anionic Polymerization with alkali hydroxides, such as. B. sodium or Potassium hydroxide or alkali alcoholates, such as. B. sodium methylate, Sodium or potassium ethylate or potassium isopropylate as catalyze sators and with the addition of at least one starter molecule, the 2 to 8, preferably 2 to 3, reactive hydrogen atoms bound contains, or by cationic polymerization with Lewis acids, such as antimony pentachloride, boron fluoride etherate and the like. a., or bleaching earth as catalysts from one or more alkylene oxides with 2 to 4 carbon atoms in the alkylene radical. For special Monofunctional starters can also be used in the poly ether structure.

Suitable alkylene oxides are, for example, tetrahydrofuran, 1,3-propylene oxide, 1,2- or 2,3-butylene oxide, styrene oxide and preferably ethylene oxide and 1,2-propylene oxide. The alkylene oxides  can be used individually, alternately one after the other or as mixtures be used.

Examples of suitable starter molecules are: water, organic dicarboxylic acids, such as succinic acid, adipic acid, Phthalic acid and terephthalic acid, aliphatic and aromatic, optionally N-mono-, N, N- and N, N'-dialkyl substituted Diamines with 1 to 4 carbon atoms in the alkyl radical, such as optionally mono- and dialkyl-substituted ethylenediamine, Diethylenetriamine, triethylenetetramine, 1,3-propylenediamine, 1,3- or 1,4-butylenediamine, 1,2-, 1,3-, 1,4-, 1,5- and 1,6-hexa methylenediamine, phenylenediamine, 2,3-, 2,4- and 2,6-toluenediamine and 4,4 ', 2,4'- and 2,2'-diaminodiphenylmethane. As a starter mole coolers are also suitable: alkanolamines, such as. B. ethanol amine, N-methyl and N-ethylethanolamine, dialkanolamines, such as. B. Diethanolamine, N-methyl and N-ethyldiethanolamine, and tri alkanolamines such as B. triethanolamine, and ammonia. virtue wise are used, especially two and / or trihydric alcohols, such as ethanediol, 1,2-propanediol and 2,3, Diethylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, Glycerin, trimethylolpropane, pentaerythritol.

The polyether polyols, preferably polyoxypropylene and poly oxypropylene polyoxyethylene polyols have functionality of preferably 2 to 8 and in particular 2 to 3 and molecular weights from 300 to 8000, preferably 300 to 6000 and ins special 1000 to 5000 and suitable polyoxytetramethylene glycols a molecular weight up to about 3500.

Polymer-modified are also suitable as polyether polyols Polyether polyols, preferably graft polyether polyols, ins especially those based on styrene and / or acrylonitrile in situ polymerization of acrylonitrile, styrene or preferably Mixtures of styrene and acrylonitrile, e.g. B. in weight ratio 90: 10 to 10: 90, preferably 70: 30 to 30: 70, expediently in the aforementioned polyether polyols analogous to the details of German patents 11 11 394, 12 22 669 (US 3304273, 3383351, 3523093), 11 52 536 (GB 1040452) and 11 52 537 (GB 987618) are made, as well as polyether poly dispersions, which as disperse phase, usually in an amount of 1 to 50% by weight, preferably 2 to 25 wt .-%, contain: z. B. polyureas, Polyhydrazide, poly containing tert-amino groups urethanes and / or melamine and the z. B. are described in EP-B-011752 (US 4304708), US-A-4374209 and DE-A-32 31 497.  

The polyether polyols can be used individually or in the form of mixtures be used.

In addition to the described polyether polyols, for example also polyether polyamines and / or other polyols selected from the group of polyester polyols, polythioether polyols, polyesters amides, hydroxyl-containing polyacetals and hydroxyl groups containing aliphatic polycarbonates or mixtures at least two of the polyols mentioned are used. The The hydroxyl number of the polyhydroxyl compounds is in all Rule 20 to 80 and preferably 28 to 56.

Suitable polyester polyols can, for example, from organic Dicarboxylic acids having 2 to 12 carbon atoms, preferably aliphatic dicarboxylic acids with 4 to 6 carbon atoms, polyhydric alcohols, preferably diols, with 2 to 12 carbons atoms, preferably 2 to 6 carbon atoms usual procedures are produced. Usually the organic polycarboxylic acids and / or derivatives and more valuable alcohols, advantageously in a molar ratio of 1: 1 to 1.8, preferably from 1: 1.05 to 1.2, catalyst-free or preferably in the presence of esterification catalysts moderately in an atmosphere of inert gas, such as. B. stick fabric, carbon monoxide, helium, argon and the like a., in the melt at Temperatures of 150 to 250 ° C, preferably 180 to 220 ° C, optionally under reduced pressure to the desired Acid number, which is advantageously less than 10, preferably is less than 2, polycondensed. The polyesters obtained polyols preferably have a functionality of 2 to 4, in particular 2 to 3, and a molecular weight of 480 to 3000, especially 600 to 2000.

The flexible polyurethane foams can be with or without use of chain extenders and / or crosslinking agents are produced, but these are usually not required are. As a chain extender and / or cross-linking agent diols and / or triols with molecular weights are used less than 400, preferably 60 to 300 for example aliphatic, cycloaliphatic and / or arali phatic diols with 2 to 14, preferably 4 to 10 carbon atoms, such as B. ethylene glycol, 1,3-propanediol, 1,10-decanediol, o-, m-, p-dihydroxycyclohexane, diethylene glycol, dipropylene glycol and preferably 1,4-butanediol, 1,6-hexanediol and bis- (2-hydroxy ethyl) hydroquinone, triols, such as 1,2,4- and 1,3,5-trihydroxycyclo hexane, triethanolamine, diethanolamine, glycerin and trimethylol propane and low molecular weight hydroxyl-containing polyalkylene oxides  based on ethylene and / or 1,2-propylene oxide and aforementioned diols and / or triols as starter molecules.

Provided chain extension for the production of the PUR foams agents, crosslinking agents or mixtures thereof are used, these expediently come in an amount of up to 10% by weight, based on the weight of the polyol compounds.

As blowing agent (d) from polyurethane chemistry all Commonly known chlorofluorocarbons (CFCs) and highly and / or perfluorinated hydrocarbons can be used. The However, the use of these substances becomes strong for ecological reasons restricted or completely discontinued. In addition to HCFC and HFC offer aliphatic and / or cycloaliphatic carbons hydrogen, in particular pentane and cyclopentane or acetals, such as B. methylal, as an alternative blowing agent. This physi Kalische blowing agents are usually the polyol component added to the system. However, you can also use the isocyanate component or as a combination of both the polyol component also be added to the isocyanate component. It is also possible their use together with high and / or perfluorinated Hydrocarbons, in the form of an emulsion of the polyol component. As emulsifiers, if they are used, are more common as oligomeric acrylates used as side groups poly contain oxyalkylene and fluoroalkane residues bound and one Have fluorine content of about 5 to 30 wt .-%. such Products are well known from plastics chemistry, e.g. B. EP-A-0,351,614th The amount of blowing agent used or Blowing agent mixture is 1 to 25 wt .-%, preferably as 1 to 15 wt .-%, each based on the total weight of components (b) to (d).

It is also possible and customary to use polyol as a blowing agent component water in an amount of 0.5 to 15 wt .-%, preferred as 1 to 5 wt .-%, based on the total weight of the components ten (b) to (h). The water additive can be combined with the use of the other blowing agents described.

As catalysts (e) for the production of flexible polyurethane foam Substances are used in particular, which the Reaction of the reactive hydrogen atoms, especially hydroxyl group-containing compounds of components (b), (c) and (d), with the organic, optionally modified polyisocyanates (a) accelerate strongly. Organic metals can be considered compounds, preferably organic tin compounds, such as Tin (II) salts of organic carboxylic acids, e.g. B. Tin (II) - acetate, tin (II) octoate, tin (II) ethylhexoate and tin (II) -  laurat, and the dialkyltin (IV) salts of organic carbon acids, e.g. B. dibutyltin diacetate, dibutyltin dilaurate, dibutyl tin maleate and dioctyltin diacetate. The organic metal compounds are used alone or preferably in combination with strongly basic amines. For example Amidines such as 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine, tertiary Amines, such as triethylamine, tributylamine, dimethylbenzylamine, N-methyl, N-ethyl, N-cyclohexylmorpholine, N, N, N ', N'-tetra methyl ethylenediamine, N, N, N ', N'-tetramethylbutanediamine, N, N, N', N'- Tetramethylhexanediamine-1,6, pentamethyldiethylenetriamine, tetra methyldiaminoethyl ether, bis (dimethylaminopropyl) urea, Dimethylpiperazine, 1,2-dimethylimidazole, 1-azabicyclo- (3,3,0) - octane and preferably 1,4-diazabicyclo (2,2,2) octane, and amino alkanol compounds, such as triethanolamine, triisopropanolamine, N-methyl and N-ethyldiethanolamine and dimethylethanolamine. As Catalysts are also suitable: tris (dialkylamino alkyl) -s-hexahydrotriazines, especially tris- (N, N-dimethylamino propyl) -s-hexahydrotriazine, tetraalkylammonium hydroxides, such as Tetramethylammonium hydroxide, alkali hydroxide such as sodium hydroxide, and alkali alcoholates, such as sodium methylate and potassium isopropylate, and alkali salts of long-chain fatty acids with 10 to 20 carbon atoms and possibly pendant OH groups. 0.001 to 5% by weight are preferably used, in particular 0.05 to 2% by weight of catalyst or catalyst combination, based on the weight of components (b) to (h).

The stabilizers (f) are, in particular, surface-active Substances, d. H. Connections used to the sub support the homogenization of the raw materials and where appropriate, the cell structure of art regulate fabrics. Examples include emulsifiers, such as the sodium salts of castor oil sulfates or fatty acids as well Salts of fatty acids with amines, e.g. B. oleic acid diethylamine, stearic acid diethanolamine, ricinoleic acid diethanolamine, salts of sulfonic acids, e.g. B. alkali or ammonium salts of dodecyl benzene or dinaphthylmethane disulfonic acid and ricinoleic acid; Foam stabilizers, such as siloxane oxalkylene copolymers and other organopolysiloxanes, oxyethylated alkylphenols, oxyethylated fatty alcohols, paraffin oils, castor oil or ricinol acid esters, Turkish red oil and peanut oil, and cell regulators such as Paraffins, fatty alcohols and dimethylpolysiloxanes. The upper Surfactants are usually used in amounts of 0.01 up to 5 parts by weight, based on 100 parts by weight of components (b) to (h).  

According to the invention, melamine is used as the flame retardant (g) in Proportions greater than 25 wt .-%, based on the total weight of components (b) to (h). The grain size the melamine is usually 1 to 100 μm, preferably 10 to 50 µm.

Other suitable flame retardants in combination with Melamine can be used, for example, tricresyl phosphate, tris (2-chloroethyl) phosphate, tris (2-chloropropyl) - phosphate, tetrakis (2-chloroethyl) ethylene diphosphate, dimethyl methanephosphonate, diethanolaminomethylphosphonic acid diethyl ester as well as commercially available halogen-containing flame retardant polyols. Except the halogen-substituted phosphates already mentioned also inorganic or organic flame retardants, such as red Phosphorus, aluminum oxide hydrate, antimony trioxide, arsenic oxide, Ammonium polyphosphate and calcium sulfate or expandable graphite or Mixtures of these flame retardants and / or optionally aromatic polyester to flame retard the soft polyurethane foams can be used. In general, it has been useful moderately proven, 5 to 50 parts by weight, preferably 5 to 25 parts by weight Parts, the flame retardant mentioned for 100 parts by weight components (b) to (h). The proportion of melamine of the total amount of flame retardant used is at least 60% by weight, preferably 70 to 90% by weight.

The reaction mixture for the preparation of the invention Flame retardant flexible polyurethane foams can be given if other aids and / or additives (h) be loved. Examples include fillers and paints substances, pigments and hydrolysis inhibitors as well as fungistatic and bacteriostatic substances.

As fillers, especially reinforcing fillers substances are the usual organic and known per se inorganic fillers, reinforcing agents, weighting agents, Agents for improving the abrasion behavior in paints, Understand coating agents, etc. In particular, be with Playfully called: inorganic fillers, such as silicate Minerals, for example layered silicates, such as antigorite, Serpentine, hornblende, ampibole, chrisotile and talc, metal oxides, such as kaolin, aluminum oxides, titanium oxides and iron oxides, Metal salts such as chalk, heavy spar and inorganic pigments, such as cadmium sulfide and zinc sulfide, and glass and. a .. Preferably Kaolin (China Clay), aluminum silicate and Co precipitates from barium sulfate and aluminum silicate as well as natural liche and synthetic fibrous minerals, such as wollastonite, Metal and in particular glass fibers of different lengths, the  can optionally be arbitrated. As an organic filling For example, substances are considered: coal, rosin, Cyclopentadienyl resins and graft polymers as well as cellulose fibers, polyamide, polyacrylonitrile, polyurethane, polyester fibers based on aromatic and / or aliphatic Dicarboxylic acid esters and especially carbon fibers. The inorganic and organic fillers can be used individually or as Mixtures are used and are the reaction mixture before advantageously in amounts of 0.5 to 50% by weight 1 to 40 wt .-%, based on the weight of components (a) to (c), but the content of mats, nonwovens and Fabrics made from natural and synthetic fibers up to 80 can reach.

Details of the other usual auxiliary and additives are in the specialist literature, for example the Monograph by J. H. Saunders and K. C. Frisch "High Polymers" Volume XVI, Polyurethanes, Parts 1 and 2, Verlag Interscience Publishers 1962 or 1964, or the plastic cited above manual, Polyurethane, Volume VII, Hanser Verlag Munich, Vienna, 1st to 3rd edition.

To produce the foams according to the invention organic and / or modified organic polyiso cyanates (a), the polyether mixture (b) and optionally further hydrogen atoms reactive towards isocyanates pointing compounds (c) and other components (d) to (h) implemented in such amounts that the equivalence ratio of NCO groups of the polyisocyanates (a) to the sum of reactive hydrogen atoms of components (b) to (h) 0.70 to 1.25: 1, preferably 0.90 to 1.15: 1.

Polyurethane foams by the process according to the invention are advantageously based on the one-shot process, for example wise with the help of high pressure or low pressure technology open or closed molds, for example metallic molds. This is also common continuous application of the reaction mixture to suitable Belt lines for the production of foam blocks.

After two, it has proven to be particularly advantageous component process to work and the assembly components (b) to (h) to a so-called polyol component, often also as Component A referred to combine and as isocyanate component, often referred to as component B, the organic and / or modified organic polyisocyanates (a), especially preferably an NCO prepolymer or mixtures of this prepolymer  and other polyisocyanates, and optionally blowing agents medium (d) to use.

The starting components are at a temperature of 15 to 90 ° C, preferably from 20 to 60 ° C and in particular from 20 to 35 ° C, mixed and in the open or optionally under increased pressure introduced into the closed mold or on a belt on a continuous workstation, that absorbs the reaction mass, applied. The mixing can be mechanically by means of a stirrer, by means of a stirrer snail or by high pressure mixing in a nozzle be performed. The mold temperature is appropriate moderately 20 to 110 ° C, preferably 30 to 60 ° C and ins particularly 35 to 55 ° C.

The flexible polyurethane foams produced by the process according to the invention have a density of 10 to 800 kg / m ³ , preferably 30 to 100 kg / m ³ and in particular 30 to 80 kg / m ³ . They are particularly suitable as upholstery for furniture and vehicle seats.

The present invention is based on the examples given are explained, but without a corresponding one limit.

A flexible polyurethane foam according to that listed in Table 1 Components are at a mold temperature of 50 ° C (KZ 95) foamed.  

Table 1

Flame retardant soft foams

Claims (9)

1. Process for the production of flame-retardant flexible polyurethane foams by reacting organic and / or modified organic polyisocyanates (a) with a polyether mixture (b) and optionally further compounds containing hydrogen atoms which are reactive toward isocyanates (c) in the presence of water and / or others Blowing agents (d), catalysts (e), stabilizers (f), flame retardants (g) and optionally other auxiliaries and additives (h), characterized in that the polyetherol mixture (b) consists of

• 1. at least one at least two-functional polyetherol based on propylene oxide and / or butylene oxide and ethylene oxide, the ethylene oxide content, based on the total amount of alkylene oxide used, being less than 25% by weight, with an OH number of 20 to 80 mg KOH / g and a proportion of primary OH groups greater than 70% and
• 2. at least one polyetherol based on propylene oxide and / or butylene oxide and ethylene oxide with an OH number of greater than 30 mg KOH / g and a proportion of primary OH groups less than 70%

and as flame retardant (g) melamine, optionally in a mixture with other flame retardants, is used. 2. The method according to claim 1, characterized in that the weight ratio (b1) to (b2) is greater than 0.3. 3. The method according to claim 1 or 2, characterized in that melamine in proportions greater than 25% by weight, based on on the total weight of components (b) to (h) becomes. 4. The method according to any one of claims 1 to 3, characterized records that water in proportions of 1 to 5 parts by weight, refer to the total weight of components (b) to (h), is used.   5. The method according to any one of claims 1 to 4, characterized characterized that as organic and / or modified organic polyisocyanates (a) tolylene diisocyanate, mixtures from diphenylmethane diisocyanate isomers, mixtures of Diphenylmethane diisocyanate and polyphenylpolymethylene poly isocyanate or tolylene diisocyanate with diphenylmethane diisocyanate and / or polyphenylpolymethylene polyisocyanate be used. 6. The method according to any one of claims 1 to 5, characterized characterized that as organic and / or modified organic polyisocyanates (a) mixtures of diphenylmethane diisocyanate isomers with proportions of 2,4'-diphenylmethane diisocyanate of at least 10 wt .-% can be used. 7. The method according to any one of claims 1 to 6, characterized characterized that as organic and / or modified organic polyisocyanates (a) prepolymers containing NCO groups, formed from the reaction of the isocyanates (a) with the poly etherols (b) and optionally components (c) and / or (d) can be used. 8. Flexible polyurethane foams, producible according to one of the Claims 1 to 7. 9. Use of the flexible polyurethane foams according to claim 8 as upholstery for furniture and vehicle seats.