EP3652230A1 - Flexible foam with halogen-free flame retardant - Google Patents

Abstract

The present invention relates to flame retarded polyurethane flexible foams, comprising phosphazene, as well as processes for the production of flexible PUR foams by reacting a component A containing: A1, an isocyanate-reactive component, A2 , a porogen containing water, A3, optionally an adjuvant and an additive, A4, a flame retardant, with B, an isocyanate component, characterized in that flame retardant A4 contains a phosphazene of formula (I): [PmNmXk] (I), wherein X independently of one another is O-aryl or NR-aryl, and at least one aryl group being substituted, X being a bridge, R being selected from group consisting of H, C1-C4 alkyl and aryl, and m is 1 to 5, particularly preferably 3 or 4, where k is m-dependent and 0 to 2m, and phosphazene did not and no isocyanate-reactive group.

Description

 SOFT FOAM WITH HALOGEN-FREE FLAME PROTECTION

The present invention relates to flame-retardant and open-cell polyurethane flexible foams (also referred to below as "flexible polyurethane foams") with phosphazene, and to processes for their preparation and the use of phosphazene as a flame retardant in a system for producing flexible polyurethane foams.

Like all organic polymers, flexible polyurethane foams are also combustible, with the large surface area per unit mass in foams reinforcing this behavior. PUR flexible foams are used, for example, in the furniture industry as seat cushions or generally as noise and heat insulation materials. In many areas of use of flexible polyurethane foams, therefore, a fire protection equipment by added flame retardants is required. There are flame retardants that choke the flame in the gas phase and there are flame retardants that protect the surface of the polymeric material by promoting charring or forming a glassy coating. As flame retardants, halogen-containing compounds and nitrogen and phosphorus compounds are preferably used. Compounds containing halogens and low-valency phosphorus compounds are considered typical of flame retardants that choke flames. Higher-valent phosphorus compounds are said to cause catalytic cleavage of the polyurethanes and thereby lead to the formation of a solid, polyphosphate-containing and charred surface. This intumescent layer protects the material against further combustion (G.W. Becker, D. Braun: Polyurethanes In: G. Oertel (ed.), Kunststoff Handbuch, Munich, Carl Hanser Verlag, 1983, 2, 104-1-5).

Typical flame retardants are e.g. Melamine or trischloropropyl phosphate (TCPP). Solids such as melamine have the disadvantage of sedimenting in the reaction mixture. By incorporating insoluble solids into the reaction mixture, the resulting foams become hard. This is often difficult to compensate. Liquid flame retardants such as TCPP do not have this disadvantage. On the contrary, compounds such as TCPP have the advantage of being relatively volatile and of being able to intervene in the radical chain reaction taking place in a flame. As a result, the temperature of the flame is reduced, which in turn reduces the decomposition of the inflamed material.

A disadvantage of the halogen-containing representatives of these classes, however, is that they are relatively volatile and can migrate from the foam (JC Quagliano, VM Wittemberg, ICG Garcia: Recent Advances on the Utilization of Nanoclays and Organophosphorus Compounds in Polyurethanes Foams for Increasing Flame Retardancy. In: J. Njuguna (Ed.), Structural Nanocomposites, Engineering Materials, Berlin Heidelberg, Springer Verlag, 2013, 1, 249-258) and when used in the combustion process, corrosive hydrohalic acid is formed.

Due to the increasing spread of organic halogen compounds with partial adverse health effects in the environment, the interest is directed to halogen-free alternatives, e.g. on halogen-free phosphate esters and phosphite esters (S.V. Levchik, E.D. Weil: A Review of Recent Progress in Phosphorus-based Flame Retardants, J. Fire Sci., 2006, 24, 345-364) and on red phosphorus.

However, these halogen-free alternatives also have disadvantages: in some cases they are sensitive to hydrolysis under the alkaline conditions typical for PU foam systems, or their effectiveness is unsatisfactory. Red phosphorus has disadvantages, e.g. in terms of rapid absorption of moisture and rapid oxidation, resulting in a loss of flame retardancy and possibly the formation of toxic phosphines, and also tends to powder explosions. Often, red phosphorus is microencapsulated to overcome these problems (L. Chen, Y.-Z. Wang: A review on flame retardant technology in China.) Part 1: Development of flame retardants, Polym. Adv. Technol., 2010, 21, 1-26). Phosphazenes are hybrid inorganic / organic materials that occur as linear and cyclic molecular structures (S.-Y.Lu, I. Hammerton: Recent developments in the chemistry of halogen-free flame retardant polymers, Prog. Polym. Sei., 2002, 27 , 1661-1721). The use of cyclic phosphazenes as flame retardants has been described e.g. for thermoplastic polyurethanes in JP 51037151 A2, for printed circuit boards in JP 2011028129 A2, for hot adhesives in JP 2013001833 A2, for textile coating in JP 2014141598 A2 and for fibers in WO 2007/074814 Al.

Polyurethane rigid foams were mixed with various, mostly NCO-reactive phosphazenes to obtain a higher thermal stability (CN 103992353 A and CN 102816186 A). Flexible polyurethane foams have already been crosslinked with NCO-reactive phosphazenes. As a result, the vapor pressure was reduced and the additive could not in the Gas phase act. Thus, it is reported in JP 01190718 that substances of the type P3N ₃ (NHCH ₂ OH) m (OR) 6-m lead to a reduction of the flue gas density, ie to a complete combustion of polyurethane flexible foams. P3N3 (NH ₂ ) 2 (OC ₆ H 5) 4 (melting point 104 ° C-105 ° C) was incorporated in a proportion of 25% by weight in component B in a TDI-based flexible polyurethane foam (Y. Kurachi, T Okuyama, T. Oohasi, J. Mater, Sci., 1989, 24, 2761-2764) and resulted in little improvement in the LOI (Limiting Oxygen Index).

However, the improved fire properties of the polyurethane foams in the aforementioned publications are obtained by a very high weight fraction of phosphazene, up to a complete construction of the polyol by Pho sphazenderivate.

Furthermore, phosphazenes, which can be incorporated into a polyurethane matrix via isocyanate-reactive groups, are expensive to produce only over several stages because they use protective group strategies (CN 102766167 A, CN 102766168 A and NN Reed, KD Janda: Stealth Star Polymers: A New High - Loading Scaffold for Liquid Phase Organic Synthesis, Org. Lett, 2000, 2, 1311-1313).

The object of the present invention is therefore to enable the production of flexible polyurethane foams containing halogen-free flame retardants, the disadvantages of the prior art in relation to the process and the produced flexible polyurethane foams are obtained, in particular the produced flexible polyurethane foams should still have low densities and compression hardness, and a good flame retardancy.

This object has been achieved by the use according to the invention of phosphazene according to the formula (I) as flame retardant component in the production of flexible polyurethane foams.

The invention relates to a process for the production of open-celled soft polyurethane foams by the reaction of a component A containing

Al is an isocyanate-reactive component,

A2 propellant, containing water, A3 optionally auxiliary and additive A4 flame retardant, with

 B is an isocyanate component, characterized in that the flame retardant A4 contains a phosphazene according to the formula (I)

[PmNmXk] (I), where

X independently represents O-aryl or NR-aryl and at least one aryl group is substituted, wherein X can represent a bridge, R is selected from the group of H, C 1 -C 4 -alkyl and aryl, and m is a number of 1 to 5, preferably 3 or 4, k is dependent on m and is a number from 0 to 2m and the phosphazene carries no isocyanate-reactive groups.

Surprisingly, it has been found that not only the fire protection properties of the flexible polyurethane foams according to the invention with phosphazenes according to the formula (I) are improved as flame retardants, but also the damping of the flexible polyurethane foams is more advantageous.

In the context of the invention, an open-pore flexible polyurethane foam is a flexible polyurethane foam which preferably has such a good exchange of air that no substantial shrinkage occurs, that is to say that when a foam sample (50 × 50 × 30 mm ³ ) is stored Core of the foam in a circulating air dryer at 100 ° C for 20 hours, the dimension decreases in any direction by more than 2% by volume.

Component AI At least one polyol selected from the group consisting of polyether polyols, polyester polyols, polyetherester polyols, polycarbonate polyols and polyether polycarbonate polyols is used as the isocyanate-reactive component Al. Preferred are Polyester polyols and / or polyether polyols. The individual polyol component may preferably have a hydroxyl number between 20 to 2000 mg KOH / g, in particular 25 to 60 mg KOH / g and particularly preferably 27 to 37 mg KOH / g. Preferably, the single polyol component has a number average molecular weight of 2000 g / mol to 15000 g / mol, in particular 3000 g / mol to 12000 g / mol and particularly preferably 3500 g / mol to 6500 g / mol. If more than one isocyanate-reactive component is used, the mixture may preferably have a hydroxyl number between 20 to 2000 mg KOH / g, in particular 25 to 100 mg KOH / g. Preferably, the mixture may have an equivalent weight of 0.8 to 2.2 kg / mol. The number-average molar mass M _n (also: molecular weight) is determined in the context of this invention by gel permeation chromatography according to DIN 55672-1 (August 2007).

The OH number (also: hydroxyl number) indicates in the case of a single added polyol its OH number. Information on the OH number for mixtures relates to the number-average OH number of the mixture, calculated from the OH numbers of the individual components in their respective molar proportions. The OH number indicates the amount of potassium hydroxide in milligrams, which is equivalent to the amount of acetic acid bound upon acetylation of one gram of the substance. It is determined in the context of the present invention according to the standard DIN 53240-1 (June 2013). "Functionality" in the context of the present invention denotes the theoretical mean value calculated from the known starting materials and their quantitative ratios (number of functions which are reactive toward isocyanates or polyols relative to polyols in the molecule).

The equivalent weight indicates the ratio of the number average molecular weight and the functionality of the isocyanate-reactive component. The equivalent weight data for mixtures are calculated from equivalent weights of the individual components in their respective molar proportions and refer to the number average equivalent weight of the mixture.

The polyester polyols of component AI may, for example, polycondensates of polyhydric alcohols, preferably diols, having 2 to 12 carbon atoms, preferably having 2 to 6 carbon atoms, and polycarboxylic acids, such as. B. Di, tri or even tetracarboxylic acids or hydroxycarboxylic acids or lactones, it is preferred to use aromatic dicarboxylic acids or mixtures of aromatic and aliphatic dicarboxylic acids. Instead of the free polycarboxylic acids, it is also possible to use the corresponding polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters of lower alcohols for the preparation of the polyesters.

Suitable carboxylic acids are, in particular: succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, tetrahydrophthalic acid, hexahydrophthalic acid, cyclohexanedicarboxylic acid,

Tetrachlorophthalic acid, itaconic acid, malonic acid, 2-methylsuccinic acid, 3,3-diethylglutaric acid, 2,2-dimethylsuccinic acid, dodecanedioic acid,

Endomethylenetetrahydrophthalic, dimer fatty, trimeric, citric, trimellitic, benzoic, maleic, fumaric, phthalic, isophthalic and terephthalic acids. It is also possible to use derivatives of these carboxylic acids, for example dimethyl terephthalate. The carboxylic acids can be used both individually and in admixture. Adipic acid, sebacic acid and / or succinic acid, particularly preferably adipic acid and / or succinic acid, are preferably used as the carboxylic acids.

Hydroxycarboxylic acids which may be co-used as reactants in the preparation of a hydroxyl-terminated polyester polyol include lactic acid, malic acid, hydroxycaproic acid, hydroxybutyric acid, hydroxydecanoic acid, hydroxystearic acid and the like. Suitable lactones include caprolactone, butyrolactone and homologs.

For the preparation of the polyester polyols in particular also bio-based starting materials and / or their derivatives in question, such as. Castor oil, polyhydroxy fatty acids, ricinoleic acid, hydroxyl modified oils, grape seed oil, black cumin oil, pumpkin seed oil, borage seed oil, soybean oil, wheat seed oil, rapeseed oil, sunflower seed oil, peanut oil, apricot kernel oil, pistachio oil, almond oil, olive oil, macadamia nut oil, avocado oil, sea buckthorn oil, sesame oil, hemp seed oil, Hazelnut oil, primrose oil, wild rose oil, thistle oil, walnut oil, fatty acids, hydroxyl-modified and epoxidized fatty acids and fatty acid esters, for example based on myristoleic acid, palmitoleic acid, oleic acid, vaccenic acid, petroselinic acid, gadoleic acid, erucic acid, nervonic acid, linoleic acid, alpha- and gamma-linolenic acid, stearidonic acid, Arachidonic acid, timnodonic acid, clupanodonic acid and cervonic acid. Particular preference is given to esters of ricinoleic acid with polyfunctional alcohols, for example glycerol. Also preferred is the use of mixtures of such bio-based acids with other carboxylic acids, for example phthalic acids. Examples of suitable diols are ethylene glycol, butylene glycol, diethylene glycol, triethylene glycol, polyalkylene glycols such as polyethylene glycol, furthermore 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol and isomers, Neopentyl glycol or hydroxypivalic acid neopentyl glycol ester. Preferably used are ethylene glycol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol or mixtures of at least two of said diols, in particular mixtures of 1,4-butanediol, 1,5-pentanediol and 1, 6-hexanediol.

In addition, it is also possible to use polyols, such as trimethylolpropane, glycerol, erythritol, pentaerythritol, trimethylolbenzene or trishydroxyethyl isocyanurate, with glycerol and trimethylolpropane being preferred. It is also possible to use monohydric alkanols.

Polyether polyols used according to the invention are obtained by preparation methods known to the person skilled in the art, for example by anionic polymerization of one or more alkylene oxides having 2 to 4 carbon atoms with alkali hydroxides, such as sodium or potassium hydroxide, alkali metal alkoxides, such as sodium methylate, sodium or potassium ethylate or potassium isopropylate, or amine alkoxylation - Catalysts, such as dimethylethanolamine (DMEOA), imidazole and / or imidazole derivatives, using at least one starter molecule containing 2 to 8, preferably 2 to 6 reactive hydrogen atoms bonded.

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 in succession or as mixtures. Preferred alkylene oxides are propylene oxide and ethylene oxide, particularly preferred are copolymers of propylene oxide with ethylene oxide. The alkylene oxides can be reacted in combination with C0 ₂ . Suitable starter molecules are, for example: 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 having 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-hexamethylenediamine, phenylenediamines, 2,3-, 2,4- and 2, 6-toluenediamine and 2,2'-, 2,4'- and 4,4'-diaminodiphenylmethane.

Preferably used are dihydric or polyhydric alcohols, such as ethanediol, 1,2- and 1,3-propanediol, diethylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, triethanolamine, bisphenols, glycerol, trimethylolpropane, pentaerythritol, sorbitol and sucrose.

Useful polycarbonate polyols are hydroxylated polycarbonates, for example polycarbonate diols. These are formed in the reaction of carbonic acid derivatives, such as diphenyl carbonate, dimethyl carbonate or phosgene, with polyols, preferably diols. Examples of such diols are ethylene glycol, 1,2- and 1,3-propanediol, 1,3- and 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, 1,4-bis-hydroxymethylcyclohexane, 2- Methyl-1, 3-propanediol, 2,2,4-Trimethylpentandiol- 1, 3, dipropylene glycol, polypropylene glycols, dibutylene glycol, polybutylene glycols, bisphenols and lactone-modified diols of the type mentioned above. Instead or in addition to pure polycarbonate diols and polyether polycarbonate can be used , which are obtainable for example by copolymerization of alkylene oxides, such as propylene oxide, with C0 ₂ .

Useful polyetherester polyols are those compounds containing ether groups, ester groups and OH groups. Organic dicarboxylic acids having up to 12 carbon atoms are useful in making the polyetherester polyols, preferably aliphatic dicarboxylic acids having from 4 to 6 carbon atoms or aromatic dicarboxylic acids used singly or in admixture. Examples which may be mentioned are suberic acid, azelaic acid, decanedicarboxylic acid, maleic acid, malonic acid, phthalic acid, pimelic acid and sebacic acid, and in particular glutaric acid, fumaric acid, succinic acid, adipic acid, phthalic acid, terephthalic acid and isoterephthalic acid. In addition to organic dicarboxylic acids and derivatives of these acids, for example their anhydrides and their esters and half esters are used with low molecular weight, monofunctional alcohols having 1 to 4 carbon atoms. The proportionate use of the abovementioned bio-based starting materials, in particular of fatty acids or fatty acid derivatives (oleic acid, soybean oil etc.) is likewise possible and can have advantages, for example with regard to storage stability of the polyol formulation, dimensional stability, fire behavior and compressive strength of the foams.

As a further component for the preparation of the polyetherester polyols polyether polyols are used which are obtained by alkoxylating starter molecules such as polyhydric alcohols. The starter molecules are at least difunctional, but may optionally also contain fractions of higher-functional, in particular trifunctional, starter molecules.

Starter molecules are, for example, diols, such as 1,2-ethanediol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,10-decanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butene-1, 4-diol and 2-butyne-1,4-diol, ether diols such as diethylene glycol, triethylene glycol, tetraethylene glycol, dibutylene glycol, tributylene glycol, tetrabutylene glycol, dihexylenglycol, Trihexylenglykol, tetrahexylenglycol and oligomer mixtures of alkylene glycols, such as diethylene glycol. Also, starter molecules with non-OH functionalities can be used alone or in mixture.

In addition to the diols, compounds having at least 3 Zerewitinoff-active hydrogens, in particular having number-average functionalities of from 3 to 8, in particular from 3 to 6, can also be used as starter molecules for the preparation of the polyethers, for example 1,1,1-trimethylolpropane, triethanolamine, Glycerol, sorbitan and pentaerythritol and triols or tetraols started polyethylene oxide polyols.

Polyetheresterpolyole can also be prepared by the alkoxylation, in particular by ethoxylation and / or propoxylation, of reaction products obtained by the reaction of organic dicarboxylic acids and their derivatives and components with Zerewitinoff-active hydrogens, in particular diols and polyols. As derivatives of these acids, for example, their anhydrides can be used, such as phthalic anhydride. Preparation processes of the polyols are described, for example, by Ionescu in "Chemistry and Technology of Polyols for Polyurethanes", Rapra Technology Limited, Shawbury 2005, p.55 et seq. (Chapter 4: Oligo-Polyols for Elastic Polyurethanes), page 263 et seq 8: Polyester Polyols for Elastic Polyurethanes) and in particular on page 311 ff. (Section 13: Polyether Polyols for Rigid Polyurethane Foams) and page 419 ff. (Section 16: Polyester Polyols for Rigid Polyurethane Foams). It is also possible to obtain polyester and polyether polyols by glycolysis of suitable polymer recyclates Suitable polyether polycarbonate polyols and their preparation are described, for example, in EP 2910585 A, [0024] - [0041] Examples of polycarbonate polyols and their preparation are found, inter alia, in EP 1359177 A. The preparation of suitable polyetheresterpolyols is described inter alia in WO 2010/043624 A and in EP 1 923 417 A.

As hydroxyl-containing compounds and polymer polyols, PHD polyols and PIPA polyols in component AI can be used. Polymer polyols are polyols which contain portions of free-radical-polymerization-capable monomers such as styrene or acrylonitrile in a base polyol-produced solid polymer. PHD (polyhydrazodicarbonamide) polyols are prepared, for example, by in situ polymerization of an isocyanate or an isocyanate mixture with a diamine and or hydrazine (or hydrazine hydrate) in a polyol, preferably a polyether polyol. The PHD dispersion is preferably prepared by reacting an isocyanate mixture of 75 to 85% by weight of 2,4-tolylene diisocyanate (2,4-TDI) and 15 to 25% by weight of 2,6-tolylene diisocyanate (2.6 -TDI) with a diamine and or hydrazine hydrate in a polyether polyol prepared by alkoxylation of a trifunctional initiator (such as glycerol and / or trimethylolpropane). Methods of preparing PHD dispersions are described, for example, in US 4,089,835 and US 4,260,530. PIPA polyols are polyisocyanate polyaddition with alkanolamine modified polyether polyols wherein the polyether polyol has a functionality of 2.5 to 4.0 and a hydroxyl number of 3 mg KOH / g to 112 mg KOH / g (molecular weight 500 g / mol to 18000 g / mol). PIPA polyols are described in detail in GB 2 072 204 A, DE 31 03 757 A1 and US Pat. No. 4,374,209. Cell-opening isocyanate-reactive substances may be copolymers of ethylene oxide and propylene oxide with an excess of ethylene oxide or aromatic diamines such as diethyltoluenediamine.

In addition to the isocyanate-reactive compounds described above, it is possible for example in component AI to comprise graft polyols, polyamines, polyamino alcohols and polythiols. The described isocyanate-reactive components also include those compounds having mixed functionality.

For the preparation of polyurethane foams in the cold foam process preferably at least two hydroxyl-containing polyether having an OH number of 20 to 50 mg KOH / g are used, wherein the OH groups to at least 80 mol of primary OH groups consist (determination by means of Ή- ΝΜΡν (eg Bruker DPX 400, deuterochloroform)). Particularly preferably, the OH number is 25 to 40 mg KOH / g, very particularly preferably 25 to 35 mg KOH / g.

Optionally, in the component Al compounds with at least two isocyanate-reactive hydrogen atoms and an OH number of 280 to 4000 mg KOH / g, preferably 400 to 3000 mg KOH / g, more preferably 1000 to 2000 mg KOH / g used. These are to be understood as meaning hydroxyl-containing and / or amino-containing and / or thiol-containing and / or carboxyl-containing compounds, preferably hydroxyl-containing and / or amino-containing compounds which serve as chain extenders or crosslinkers. These compounds generally have from 2 to 8, preferably from 2 to 4, isocyanate-reactive hydrogen atoms. For example, ethanolamine, diethanolamine, triethanolamine, sorbitol and / or glycerol can be used. Further examples of compounds that can be used as chain extenders or crosslinkers are described in EP-A-0 007 502, pages 16-17.

Component AI may consist of one or more of the above-mentioned isocyanate-reactive components.

Component A2

As blowing agent A2 chemical and physical blowing agent can be used. As a chemical blowing agent substances are called the isocyanate groups to form the propellant gas, such as in the case of water is formed Carbon dioxide and in the case of eg formic acid produces carbon dioxide and carbon monoxide, react. As the chemical blowing agent, for example, water, carboxylic acids, carbamates and mixtures thereof can be used. As the carboxylic acid, at least one compound selected from the group consisting of formic acid, acetic acid, oxalic acid, malonic acid and ricinoleic acid is preferably used. Most preferably, only water is used as the chemical blowing agent.

As a physical blowing agent used, for example, low-boiling organic compounds such. As hydrocarbons, ethers, ketones, carboxylic acid esters, carbonic acid esters, halogenated hydrocarbons. Particularly suitable are organic compounds which are inert to the isocyanate component B and have boiling points below 100 ° C, preferably below 50 ° C at atmospheric pressure. These boiling points have the advantage that the organic compounds evaporate under the influence of the exothermic polyaddition reaction. Examples of such, preferably used organic compounds are alkanes, such as heptane, hexane, n- and iso-pentane, preferably technical mixtures of n- and iso-pentanes, n- and isobutane and propane, cycloalkanes, such as cyclopentane and / or cyclohexane, ethers such as furan, dimethyl ether and diethyl ether, ketones such as acetone and methyl ethyl ketone, carboxylic acid alkyl esters such as methyl formate, dimethyl oxalate and ethyl acetate and halogenated hydrocarbons such as methylene chloride, dichloromonofluoromethane, difluoromethane, trifluoromethane, difluoroethane, tetrafluoroethane, chlorodifluoroethanes, 1,1-dichloro-2, 2,2-trifluoroethane, 2,2-dichloro-2-fluoroethane and heptafluoropropane. Also preferred is the use of (hydro) fluorinated olefins, e.g. HFO 1233zd (E) (trans -chloro-3,3,3-trifluoro-1-propene) or HFO 1336mzz (Z) (cis-1, l, l, 4,4,4-hexafluoro-2-butene ) or additives such as FA 188 of 3M (1, 1, 1, 2, 3, 4, 5, 5, 5-nonafluoro-4- (trifluoromethyl) pent-2-ene). It is also possible to use mixtures of two or more of the organic compounds mentioned. The organic compounds can also be used in the form of an emulsion of small droplets.

As blowing agent A2, at least one compound selected from the group consisting of physical and chemical blowing agents is used. Component A2 preferably comprises at least one chemical blowing agent, more preferably water.

Component A3 The auxiliaries and additives optionally used as component A3 are described, for example, in EP-A 0 000 389, pages 18-21. Examples of auxiliaries and additives which may optionally be used according to the invention and details of the use and mode of action of these auxiliaries and additives are described in the Kunststoff-Handbuch, Volume VII, edited by G. Oertel, Carl Hanser Verlag, Munich, 3rd edition, 1993. eg described on pages 104-127.

By way of example, auxiliaries and additives such as catalysts (activators), plasticizers, antioxidants, surface-active substances (surfactants), such as emulsifiers and foam stabilizers, in particular those with low emission such as products of the Tegostab® LF2 series, pigments, fillers (such as Barium sulfate, diatomaceous earth, carbon black or whiting), additives such as reaction retardants (eg acidic substances such as hydrochloric acid or organic acid halides), cell regulators (such as paraffins or fatty alcohols or dimethylpolysiloxanes), dyes, stabilizers against aging and weathering, fungistatic and bacteriostatic substances and release agents.

As catalysts there can be used, for example, amines such as aliphatic tertiary amines (eg triethylamine, tetramethylbutanediamine) and cycloaliphatic tertiary amines (eg 1,4-diaza (2,2,2) bicyclooctane), amino ethers such as aliphatic amino ethers (e.g. B. dimethylaminoethyl ether and N, N, N-trimethyl-N-hydroxyethyl-bisaminoethyl ether) and cycloaliphatic amino ethers (eg., N-ethylmorpholine), amidines, such as aliphatic amidines and cycloaliphatic amidines, urea, derivatives of urea (z Aminoalkyl ureas, see, for example, EP-A 0 176 013, in particular (3-dimethylaminopropylamine) urea), and tin catalysts (for example dibutyltin oxide, dibutyltin dilaurate, tin octoate). The catalyst used is preferably at least one compound selected from the group comprising urea, derivatives of urea, amines and amino ethers. Preferably, no tin catalysts are used.

Examples of particularly preferred catalysts are: (3-dimethylaminopropylamine) urea, 2- (2-dimethylaminoethoxy) ethanol, N, N-bis (3-dimethylaminopropyl) -N-isopropanolamine, N, N, N-trimethyl-N hydroxyethyl bisaminoethyl ether and 3-dimethylaminopropylamine. These particularly preferred catalysts have the advantage that they have a greatly reduced migration and emission behavior.

As surface-active substances are e.g. Compounds which serve to assist the homogenization of the starting materials and, if appropriate, are also suitable for regulating the cell structure of the plastics. Mention may be made, for example, of emulsifiers, such as the sodium salts of castor oil sulfates or fatty acids, and salts of fatty acids with amines, e.g. diethylamine, stearic acid diethanolamine, diethanolamine ricinoleic acid, salts of sulfonic acids, e.g. Alkali or ammonium salts of dodecylbenzene or dinaphthylmethanedisulfonic acid and ricinoleic acid; Foam stabilizers, such as siloxane-oxalkylene copolymers and other organopolysiloxanes, ethoxylated alkylphenols, ethoxylated fatty alcohols, paraffin oils, castor oil or ricinoleic acid esters, turkey red oil and peanut oil, and cell regulators, such as paraffins, fatty alcohols and dimethylpolysiloxanes. To improve the emulsifying effect, the cell structure and / or stabilization of the foam further suitable are the above-described oligomeric acrylates having polyoxyalkylene and fluoroalkane radicals as side groups.

Fillers, in particular reinforcing fillers, are the usual conventional organic and inorganic fillers, reinforcing agents, weighting agents, agents for improving the abrasion behavior in paints, coating compositions, etc. Specific examples are: inorganic fillers such as silicate minerals, for example sheet silicates such as antigorite, serpentine, hornblende, amphiboles, chrysotile, montmorillonite and talc, metal oxides such as kaolin, aluminas, titanium oxides and iron oxides, metal salts such as chalk, barite and inorganic pigments, such as cadmium sulfide and zinc sulfide, as well as glass, etc., and natural and synthetic fibrous minerals such as wollastonite, metal and especially glass fibers of various lengths, which may optionally be sized. Examples of suitable organic fillers are: carbon, melamine, rosin, cyclopentadienyl resins and graft polymers, and cellulose fibers, polyamide, polyacrylonitrile, polyurethane, polyester fibers based on aromatic and / or aliphatic dicarboxylic acid esters and in particular carbon fibers. Further suitable fillers are substances which are suitable for the production of

Dispersions can be used. For example, from reaction products

Isocyanates with a diamine and / or hydrazine hydrate, which are responsible for the formation of

PHD dispersions are used. These fillers themselves do not react with isocyanate groups.

The component A3 may consist of one or more of the auxiliaries and additives mentioned above.

Component A4

According to the present invention, phosphazenes according to the formula (I) are used as flame retardants A4,

[PmNmXk] (I), where

X independently of one another represents O-aryl or NR-aryl,

R is selected from the group of H, C1-C4 alkyl and aryl, and m is a number from 1 to 5, more preferably 3 or 4, k is a function of m and is a number from 0 to 2m.

The phosphazenes according to the invention are additionally distinguished by the fact that they contain no isocyanate-reactive groups. This is advantageous because the phosphazenes are thus not incorporated into the polyurethane framework of the flexible foam in the reaction of component A with B. As a result, they more easily enter the gas phase, where they lead to incomplete combustion and thus to less heat. This in turn is beneficial because lower heat development leads to less decomposition of the polymer. Preferably, the flame retardant A4 contains in its entirety no components with isocyanate-reactive groups. Preferably, the at least one substituent of the at least one substituted aryl group of O-aryl or NR-aryl of substituent X is selected from CN, dC ₄ alkyl, nitro, sulfonate, carboxylate or phosphonate groups, with N (aryl) being preferred with at least one C1-C4 alkyl and O-aryl is preferably substituted by at least one CN or C1-C4 alkyl group.

X in the formula (I) is particularly preferably O-aryl groups, very particularly preferably 0-C ₆ H ₄ CN, O-C ₆ H ₄ COOR, O-C ₆ H ₄ CH ₃ and mixtures thereof with 0-C H _{6. 5}

Most preferably, phosphazenes having a cyclic structure are used, which correspond to the general formulas (III) to (VI)

(VI)

independently represents O-aryl or NR-aryl, independently represents a substituted aryl radical and R is selected from the group of H, C1-C4 alkyl and aryl

Particularly suitable are the phosphazenes, which carry six aryloxy groups, which in turn at least 10% of the aryl radical further groups such. B. CH3 or CN wear: These include z. As the compounds with the CAS numbers 2040915-36-2, 1207718-93-1. It is possible to use one or more phosphazenes according to the formula (I) as flame retardant A4; in addition to the phosphazenes according to the formula (I), it is also possible to use further flameproofing agents. The proportion of the phosphazene according to the formula (I) on the flame retardant A4 can be e.g. 50 wt .-% to 100 wt .-%, preferably 80 wt .-% to 100 wt .-% and particularly preferably 100 wt .-%, in each case based on the total mass of the flame retardant A4.

The proportion of phosphazene according to the formula (I) in the reaction mixture containing the components Al to A4 (without component B), can e.g. 0.5% by weight to 40.0% by weight, preferably 1.0% by weight to 20.0% by weight, particularly preferably 2.0% by weight to 15.0% by weight , amount. As further flame retardants, for example, phosphates or phosphonates, e.g. Tricresyl phosphate, diphenyl cresyl phosphate (DPK), triethyl phosphate (TEP), dimethyl methyl phosphonate (DMMP),

Diethanolaminomethylphosphonic acid diethyl ester, diethylethylphosphonate (DEEP) and / or dimethylpropylphosphonate (DMPP) or the hydroxymethylphosphonates described in US 3385801, US2015 / 0080487, DE 19744 426. In addition, further suitable flameproofing agents are, for example, brominated esters, brominated ethers (xxol) or brominated alcohols such as dibromoneopentyl alcohol, tribromoneopentyl alcohol, tetrabromophthalate diol and also chlorinated phosphates such as tris (2-chloroethyl) phosphate, tris (2-chloropropyl) phosphate (TCPP), Tris (l, 3-dichloropropyl) phosphate, tris (2,3-dibromopropyl) phosphate, tetrakis (2-chloroethyl) ethylenediphosphate, as well as commercially available halogen-containing flame retardant polyols. Preference is given to using halogen-free flame retardants, particularly preferably at least one compound selected from the group consisting of halogen-free phosphates and halogen-free phosphonates, more preferably at least one compound selected from the group consisting of tricresyl phosphate, diphenyl cresyl phosphate (DPK), triethyl phosphate (TEP), dimethyl methyl phosphonate (DMMP) Diethyl diethanolaminomethylphosphonate, diethylethylphosphonate (DEEP) and dimethylpropylphosphonate. Component B

As component B aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates are used, as they are e.g. by W. Siefken in Justus Liebigs Annalen der Chemie, 562, pages 75 to 136, for example those of the formula (II)

Q (NCO) _n (II) in the n = is a number between 2 to 6, preferably 2 to 3, and Q is an aromatic or aliphatic hydrocarbon radical having 2 to 40, preferably 7 to 20 C atoms, a cycloaliphatic hydrocarbon radical 4 to 15, preferably 6 to 13 C atoms or an araliphatic hydrocarbon radical having 8 to 15, preferably 8 to 13 C atoms.

These are, for example, polyisocyanates, as described in EP-A 0 007 502, pages 7-8. As a rule, the technically readily available polyisocyanates, for example the tolylene 2,4- and 2,6-diisocyanate, and any desired mixtures of these isomers ("TDI") are particularly preferred; polyphenylpolymethylene polyisocyanates, as prepared by aniline-formaldehyde condensation and subsequent phosgenation are ("crude MDI") and carbodiimide groups, urethane groups, allophanate groups, isocyanurate groups, urea groups or biuret polyisocyanates ("modified polyisocyanates" or "prepolymers"), especially those modified polyisocyanates derived from 2,4- and / or 2,6 Toluylene diisocyanate or derived from the 4,4'- and / or 2,4'- and / or 2,2'-diphenylmethane diisocyanate. Preferably, as component B at least one compound selected from the group consisting of 2,4- and 2,6-toluene diisocyanate, 4,4'- and 2,4'- and 2,2'-diphenylmethane diisocyanate and Polyphenylpolymethylenpolyisocyanat ("multi-core MDI "," PMDI "), more preferably at least one compound selected from the group consisting of 4,4'- and 2,4'- and 2,2'-diphenylmethane diisocyanate and Polyphenylpolymethylenpolyisocyanat (" multi-core MDI "or" pMDI ") used , The mixtures of diphenylmethane diisocyanate and polyphenylene polymethylene polyisocyanate ("multinuclear MDI" or "pMDI") have a preferred monomer content of between 50 and 100% by weight, preferably between 60 and 95% by weight, more preferably between 75 and 90% by weight. The NCO content of the polyisocyanate used should preferably be above 25% by weight, preferably above 30% by weight, particularly preferably above 31.4% by weight. Preferably, the MDI used should have a content of 2,4'-diphenylmethane diisocyanate of at least 3% by weight, preferably at least 15% by weight.

In addition to the abovementioned polyisocyanates, it is also possible proportionally to modify modified diisocyanates with uretdione, isocyanurate, urethane, carbodiimide, uretonimine, allophanate, biuret, amide, iminooxadiazinedione and / or oxadiazinetrione structure and unmodified polyisocyanate having more than 2 NCO groups per molecule such as 4-isocyanatomethyl-l, 8-octane diisocyanate (nonane triisocyanate) or triphenylmethane-4,4 ', 4 "-triisocyanate, etc. The quotient is used under the isocyanate index (also called characteristic number or isocyanate index) from the amount of substance [mol] of isocyanate groups actually used and the amount of substance [mol] of isocyanate-reactive groups actually used, multiplied by 100, understood:

Code = (moles of isocyanate groups / moles of isocyanate-reactive groups) * 100 It is possible that in the reaction mixture the number of NCO groups in the isocyanate and the number of isocyanate-reactive groups lead to a number (index) of 60 to 250, preferably between 70 and 130, and more preferably between 75 and 120.

The NCO value (also: NCO content, isocyanate content) is determined by means of EN ISO 11909: 2007. Unless otherwise indicated, these are the values at 25 ° C.

Component B may consist of one or more of the isocyanate components mentioned above.

The invention also relates to a flexible polyurethane foam which is produced by the process according to the invention. The flexible polyurethane foams can be produced as molded or also as block foams. Preferably, they are produced as molded foams.

The processes for producing flexible polyurethane foams are known per se and are described, for example, in US Pat. in Kunststoff-Handbuch, Volume VII, edited by Vieweg and Hochtlen, Carl Hanser Verlag, Munich 1993, pages 139-265, or by N. Adam et. al. in the chapter "Polyurethanes" in Ullmann's Encyclopedia of Industrial Chemistry, 7th edition 2005. PUR flexible foams can be produced in hot or cold foam behavior, preference being given to the cold foam process.

The process according to the invention for the production of flexible polyurethane foams from the components according to the invention leads to flexible polyurethane foams with simultaneously good flameproofing and damping properties while reducing the health disadvantages in comparison with the prior art.

The invention therefore also relates to the flexible polyurethane foams produced with the components according to the invention, and their use for the production of molded parts and the molded parts themselves.

The soft polyurethane foams obtainable according to the invention are used, for example, in furniture upholstery, textile inserts, mattresses, automobile seats, headrests, armrests, sponges and construction elements, as well as seat and armature coverings, and have characteristic numbers of 50 to 250, preferably 70 to 130, particularly preferably 75 to 115 on.

A preferred process according to the invention for the preparation of the flexible polyurethane foams according to the invention comprises the reaction of component A comprising

Al 39.50 to 99.28% by weight (based on the components A1 to A4) of a polyether polyol or of a mixture of polyether polyols, preferably polymers based on propylene oxide and ethylene oxide with a mean equivalent weight of 0.8 to 2.2 kg / mol and an average functionality of 1.8 to 6.2,

A2 0.2 to 20.0 parts by weight (based on the components AI to A4) of water,

A3 0.02 to 3.02 parts by weight (based on the components AI to A4) of aliphatic amines as catalysts, preferably those containing OH or NH groups, and bis to 30 parts by weight (based on the components AI to A4) of stably dispersed in AI and not isocyanate-reactive fillers

A4 0.5 to 8.0 parts by weight (based on the components AI to A4) of flame retardants, with the isocyanate component B, characterized in that the flame retardant A4 is a phosphazene, according to the formula (I)

[P _m N _m Xx Y 2m-x] (I).

In a further preferred embodiment cyclic phosphazenes having a melting point below the temperature reached by the foam in the preparation are used. Preference is given to phosphazenes having a melting point below 80 ° C.

In a preferred embodiment, mixtures of MDI and TDI isomers are used as component B, the weight ratio of MDI isomers to TDI isomers being between 4: 1 and 1: 4. Preferably, the mixture of MDI and TDI isomers contains 15 to 75 wt .-% of 4,4-MDI, 0 to 30 wt .-% 2,4-MDI, 10 to 30 wt .-% polymeric MDI and homologues, wherein which consist of 100 wt .-% missing portions of TDI isomers.

In a further preferred embodiment, polyhydrazodicarbonamide may be present in component A and / or B at 1 to 10% by weight, based on the total weight of components A and B.

In a first embodiment, the invention relates to a process for the preparation of open-pore PUR flexible foams by the reaction of a component A containing

Al is an isocyanate-reactive component

Propellant containing water,

A3 possibly auxiliary and additive

A4 flame retardant With

B of an isocyanate component, characterized in that the flame retardant A4 contains a phosphazene according to the formula (I) [PmNmXk] (I), wherein

X is independently O-aryl or NR-aryl and is substituted on average over all phosphazenes at least 10% of the aryl groups, wherein X can represent a bridge, R is selected from the group of H, C1-C4 alkyl and aryl, and m is a number from 1 to 5, more preferably 3 or 4, k is dependent on m and is a number from 0 to 2m and the phosphazene carries no isocyanate-reactive groups.

According to a second embodiment, the invention relates to a process according to embodiment 1, characterized in that in the isocyanate-reactive component AI polyether polyols having a hydroxyl number of 25 mg KOH / g to 2000 mg KOH / g are included.

According to a third embodiment, the invention relates to a method according to embodiment 1 or 2, characterized in that the isocyanate-reactive component AI contains a PHD polyol.

According to a fourth embodiment, the invention relates to a method according to any one of embodiments 1-3, characterized in that the blowing agent A2 contains at least one compound selected from the group consisting of halogen-free chemical blowing agents, halogen-free physical blowing agents and (hydro) fluorinated olefins , According to a fifth embodiment, the invention relates to a method according to one of the embodiments 1-4, characterized in that the flame retardant A4 contains no components with isocyanate-reactive groups.

According to a sixth embodiment, the invention relates to a process according to any one of embodiments 1-5, characterized in that the flame retardant A4 50 wt. To 100 wt., Based on the total mass of the flame retardant A4, the phosphazene according to the formula (I) contains.

According to a seventh embodiment, the invention relates to a method according to any one of embodiments 1-6, characterized in that the content of phosphazene according to formula (I) 0.5 to 40.0 parts by weight, based on the reaction mixture A1 -A4 without B, is.

According to an eighth embodiment, the invention relates to a method according to one of embodiments 1-7, characterized in that the flame retardant A4 contains at least one compound selected from the group consisting of halogen-free phosphates and halogen-free phosphonates.

According to a ninth embodiment, the invention relates to a method according to any one of embodiments 1-8, characterized in that the at least one substituent of the at least one substituted aryl group of O-aryl or NR-aryl of the substituent X is selected from CN-, Ci-C ₄ alkyl, nitro, sulfonate, carboxylate or phosphonate groups, wherein N (aryl) preferably having at least one Ci-C ₄ alkyl and O-aryl preferably having at least one CN, COOR or Ci-C ₄ alkyl group is substituted.

According to a tenth embodiment, the invention relates to a process according to any of embodiments 1-9, characterized in that the phosphazene is a cyclic phosphazene and preferably has a structure of the general formulas (III) to (VI)

Aryl ₃

(V)

 Where VI

X is independently of one another O-aryl or NR-aryl,

Aryl independently represents a substituted aryl radical and

R is selected from the group of H, Ci-C ₄ alkyl and aryl.

According to an eleventh embodiment, the invention relates to a method according to one of the embodiments 1-10, characterized in that the component contains A.

Al 39.50 to 99.28 parts by weight (based on the components Al to A4) of a polyether polyol or a mixture of polyether polyols based on propylene oxide and ethylene oxide with a middle Equivalent weight of 0.8 to 2.2 kg / mol and an average functionality of 1.8 to 6.2,

A2 0.2 to 20.0 parts by weight (based on the components AI to A4) of water,

A3 0.02 to 3.02 parts by weight (based on the components AI to A4) aliphatic amines as catalysts, preferably those containing OH or NH groups, and up to 30 parts by weight (based on the components AI to A4) on stably dispersed in Al and not isocyanate-reactive fillers,

A4 0.5 to 8.0 parts by weight (based on the components A1 to A4) of flame retardant. According to a twelfth embodiment, the invention relates to a process according to one of embodiments 1-11, characterized in that component B comprises at least one compound selected from the group consisting of 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4, 4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, polyphenylpolymethylene polyisocyanate and carbodiimide groups, urethane groups, allophanate groups, isocyanurate groups, urea groups or biuret-containing polyisocyanates derived from 2,4- and / or 2,6-toluene diisocyanate or derived from 4,4'- and / or 2,4'- and / or 2,2'-diphenylmethane diisocyanate.

According to a thirteenth embodiment, the invention relates to a method according to one of embodiments 1-12, characterized in that the content of difunctional isocyanates in the component B is 60 to 100 parts by weight, preferably 75 to 90 parts by weight, based on the component B.

According to a fourteenth embodiment, the invention relates to a flexible polyurethane foam, obtainable by the process according to one of embodiments 1 to 13, wherein the apparent density of the flexible polyurethane foam in particular

• is between 10 kg / m ³ and 20 kg / m ³ , or

Between 35 kg / m ³ and 80 kg / m ³ and the isocyanate index is between 60 and 110, or

Between 200 kg / m ³ and 300 kg / m ³ and the isocyanate index between 75 and 120. According to a fourteenth embodiment, the invention relates to the use of soft polyurethane foams according to embodiment 13 or 14 for the production of furniture upholstery, textile inserts, mattresses, automobile seats, headrests, armrests, sponges and construction elements, as well as seat and armature panels.

The preferred embodiments can be carried out individually or else linked to one another.

Examples

The present invention will be further illustrated by, but not limited to, the following examples.

Al-1 glycerol-started polyalkylene oxide with a molecular weight of 4800 g / mol is used as suspension with A3-1

A2-1 25% by weight urea in water

A3-1 reaction product of tolylene diisocyanate (TDI) and

 Hydrazine hydrate, is used as a suspension with Al-1

A3-2 mixture of Jeffcat ZF-10 ^® (Huntsman) and Dabco® 1070 NE

 (Air Products) in the weight ratio 1:20

A3-3 Tegostab ^® B 8738 LF2, Polyetherdimethylsiloxan (Evonik)

A4-1 Rabitle ^® FP 200, cyclic phosphazene with phenoxy and

 Methoxy substituents (Fushimi Pharmaceuticals, halogen-free)

A4-2 300 Rabitle ^® FP-B, cyclic phosphazene with cyano phenoxy (Fushimi Pharmaceuticals, halogen-free)

A4-3 Rabitle ^® FP 366, cyclic phosphazene with Propoxylsubstituenten

 (Fushimi Pharmaceuticals, halogen-free)

A4-4 Rabitle ^® FP 390, cyclic phosphazene with Toluyloxy- and

 Phenoxy substituents (Fushimi Pharmaceuticals, halogen-free) A4-5 Trischloropropyl phosphate, halogenated flame retardant

A4-6 melamine, halogen-free, solid flame retardant insoluble in all other components.

A4-7 NCO-reactive reaction product of 60 g A4-2 and 8 dm ³

Hydrogen in 0.42 dm ³ THF at 10 bar over Pd / C as catalyst. From the amine number of 66.45 mg KOH / g results

Equivalent weight of 884 g / mol CH ₂ -NH ₂ . ³¹ P-NMR (400 MHz, CDCl ₃ ): 8.01 and 7.94 ppm vs. H3PO4 (for comparison A4-2: 7.49, 7.54 ppm). Complete disappearance of the doublets at 7.50 ppm and 7.40 ppm in ^X H NMR (400 MHz, CDCl ₃ ) indicates complete hydrogenation of the nitrile groups in A4-2. The signal of the CH ₂ -NH ₂ group is found in ^X H-NMR at 3.70 ppm. TMS. ASAP-MS: m / z 694 (10%, M + H ⁺ , CseHsoNsOePs, CAS 1184-10-7), m / z

708 (10%, M + H ⁺ , C37H32N3O6P3), m / z 723 (60%, M + H ⁺ , C37H33N4O6P3, CAS 81525-08-8), m / z 737 (100%, M + H ⁺ , C37H35N5O6P3 ), m / z 752 (40%, M + H ⁺ , C38H36N5O6P3). C37H33N4O6P3, CAS 81525-08-8, contains an aminomethyl group. C38H36N5O6P3 contains two aminomethyl groups. Both are capable of reacting with isocyanate.

Bl Desmodur ^® 44V20L, isocyanate with 31.5 wt .-% NCO-groups and a viscosity of 0.2 Pa * s at 298K (Covestro)

B-2 Desmodur ^® T80, isocyanate with 48 wt .-% NCO groups,

 Mixture of 80 wt .-% 2,4-TDI and 20 wt .-% 2,6-TDI

(Covestro)

Production and testing of soft polyurethane foams

The fire test is based on the British Standard BS 5852: 1990-Part 2 with the ignition source 4 ("Crib"), but was performed without a textile covering layer The measurement of the density was carried out according to DIN EN ISO 845 (October 2009).

The compression hardness and the damping of the soft polyurethane foam were measured in accordance with DIN EN ISO 3386-1 (September 2010).

850 ml) and a stirrer (Pendraulik) with a standard stirring disk (d = 64 mm) at 4200 rev / min. 45. For the preparation of the flexible polyurethane foams, the required amount of component A in a paper cup with plate bottom (volume: about 850 ml) Loaded with air for seconds. Thereafter, component B was added to component A and the mixture was thoroughly mixed with a stirrer for 5 seconds. The exact composition of the individual components is shown in Table 1. To determine the characteristic reaction times, a stopwatch was started at the beginning of the mixing. Subsequently, about 93 grams of Reaction mixture in a 23 ° C warm, lined with Teflon film box mold made of aluminum with a volume of 1.6 dm ³ poured. The mold was closed and locked for 6 minutes. The mechanical tests and fire tests were determined on the molded foam, the reaction kinetics on the free-foaming reaction mixture in the cup.

The start time t _c is reached when expansion of the mixture is observed (beginning of the reaction of isocyanate and water). The setting time to determines the point in time at which threads are drawn by dabbing a wooden swab onto the surface of the rising soft polyurethane foam. The rise time t _s is reached when the expansion of the flexible polyurethane foam is finally completed. It should be noted that some systems tend to sag and then rise again.

It can be seen from Table 1, Part "Details on kinetics and mechanical properties", that Examples 2 to 5 with phosphazenes as flame retardants have similar core densities (RD) to Examples 1 and 6 without flame retardants or with TCPP as flame retardant PUR flexible foam from Example 7 with melamine as flame retardant has an increased bulk density in contrast to the remaining PUR flexible foams, but the softening effect is not as pronounced as in the case of TCPP.The effect of the flame retardants from Examples 2 to 6 can also be seen Softeners, which are correspondingly particularly well suited for flexible polyurethane foams, and Example 7 and in particular Example 7 show a marked hardening of the flexible polyurethane foam The damping of the flexible polyurethane foams of Examples 3-5 is more favorable than in comparison with the polyurethane foams. Soft foams without flame retardants, with TCPP and with melamine. Soft foams in the fire test is shown in Table 1, part "Information on behavior in fire test". From the molar proportions of the flame retardant A4 used in Examples 2 to 7, the efficiency of the flame retardant is assessed: the higher this difference, the faster the flame extinguishes and the more efficient the flame retardant. It can be seen that Examples 2 and 4, in which phosphazenes were used as flame retardants that do not have the formula (I) according to the invention, do not lead to self-extinguishing polyurethane flexible foams. Furthermore, it can be seen that Example 7, which was prepared with a non-low-melting or liquid flame retardant, leads to the same fire behavior as Example 1. Particularly strong reduction of the time to self-extinguishing per mmol of flame retardant used A4, especially 3 example. The flame retardant in Example 5 acts as well or slightly more efficient than the flame retardant in Example 6, wherein Example 6 contains a halogenated flame retardant and accordingly disadvantages z. B. by corrosive hydrochloric acid in flue gases.

Table 1: Composition of the reaction mixtures

 The indication of the weight refers to the sum of the components AI to A4 = 100% by weight.

The content of molecules with two NCO groups per molecule based on the sum of Bl and B2 is in all cases 83% by weight.

Table 1 (continued, information on kinetics and mechanical properties)

k. A .: No details can be given about the mechanical data of comparative experiment 8.

Table 1 (continued, information on behavior in the fire test)

 Proportion of the amount of substance (in mmol) of the flame retardant A4 used in each case in the experiment per total of the masses (in kg) of the employed

Components AI to A4.

 tsE: The measured time until the PUR soft foam sample is self-extinguished (ISE).

⁴⁾ AtsE: The difference in time ISE at the corresponding time measured on the reference sample without flame retardant are given in seconds.

 AtgE per mmol of flame retardant: AtgE based on the amount by weight (in mmol) of the flame retardant A4 used in each case.

Claims

claims 1. A process for the preparation of open-cell polyurethane flexible foams by the reaction of a component A containing Al is an isocyanate-reactive component A2 blowing agent, containing water, A3 possibly auxiliary and additive A4 flame retardant with B of an isocyanate component, characterized in that the flame retardant A4 contains a phosphazene according to the formula (I) [PmNmXk] (I), where X is independently of one another O-aryl or NR-aryl and, on average, all phosphazenes are substituted by at least 10% of the aryl groups, where X can represent a bridge, R is selected from the group consisting of H, C1-C4 alkyl and aryl, and m is a number from 1 to 5, more preferably 3 or 4, k is a function of m and is a number from 0 to 2m and Phosphazene carries no isocyanate-reactive groups. 2. The method according to claim 1, characterized in that contained in the isocyanate-reactive component Al polyether polyols having a hydroxyl number of 25 mg KOH / g to 2000 mg KOH / g. 3. The method according to any one of claims 1 or 2, characterized in that the isocyanate-reactive component AI contains a PHD polyol. 4. The method according to any one of claims 1-3, characterized in that the blowing agent A2 contains at least one compound which is selected from the group consisting of halogen-free chemical blowing agents, halogen-free physical blowing agents and (hydro) fluorinated olefins. 5. The method according to any one of claims 1-4, characterized in that the flame retardant A4 contains no components with isocyanate-reactive groups. 6. The method according to any one of claims 1-5, characterized in that the flame retardant A4 contains 50 parts by weight to 100 parts by weight, based on the total mass of the flame retardant A4, of the phosphazene according to the formula (I). 7. The method according to any one of claims 1-6, characterized in that the content of phosphazene according to formula (I) 0.5 wt .- to 40.0 parts by weight, based on the reaction mixture A1-A4 without B, is , 8. The method according to any one of claims 1-7, characterized in that the flame retardant A4 contains at least one compound selected from the group consisting of halogen-free phosphates and halogen-free phosphonates. 9. The method according to any one of claims 1-8, characterized in that the at least one substituent of the at least one substituted aryl group of O-aryl or NR-aryl of the substituent X is selected from CN, Ci-C ₄ alkyl, nitro , Sulfonate, carboxylate or phosphonate groups, wherein N (aryl) is preferably substituted by at least one Ci-C ₄ alkyl and O-aryl is preferably substituted by at least one CN, COOR or Ci-C ₄ alkyl group. 10. The method according to any one of claims 1-9, characterized in that the phosphazene is a cyclic phosphazene and preferably has a structure of the general formulas (III) to (VI) (III) X ₄ X ₃  (IV) l ₂  (V)  Where VI X is independently of one another O-aryl or NR-aryl, Aryl independently represents a substituted aryl radical and R is selected from the group of H, Ci-C ₄ alkyl and aryl. 11. The method according to any one of claims 1-10, characterized in that the component contains A. Al 39.50 to 99.28 parts by weight (based on the components Al to A4) of a polyether polyol or a mixture of polyether polyols based on propylene oxide and ethylene oxide with a middle Equivalent weight of 0.8 to 2.2 kg / mol and an average functionality of 1.8 to 6.2, A2 0.2 to 20.0 parts by weight (based on the components AI to A4) of water, A3 0.02 to 3.02 parts by weight (based on the components AI to A4) aliphatic amines as catalysts, preferably those containing OH or NH groups, and up to 30 parts by weight (based on the components AI to A4) on stably dispersed in Al and not isocyanate-reactive fillers, A4 0.5 to 8.0 parts by weight (based on the components A1 to A4) of flame retardant. 12. The method according to any one of claims 1-11, characterized in that component B contains at least one compound which is selected from the group consisting of 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2nd , 4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, polyphenylpolymethylene polyisocyanate and carbodiimide groups, urethane groups, allophanate groups, isocyanurate groups, urea groups or biuret-containing polyisocyanates derived from 2,4- and / or 2,6-toluene diisocyanate or from 4,4 Derive '- and / or 2,4'- and / or 2,2'-diphenylmethane diisocyanate. 13. The method according to any one of claims 1-12, characterized in that the content of difunctional isocyanates in the component B is 60 to 100 parts by weight, preferably 75 to 90 parts by weight, based on the component B. 14. Flexible polyurethane foam, obtainable by the process according to one of claims 1 to 13, wherein the apparent density of the flexible polyurethane foam in particular • is between 10 kg / m ³ and 20 kg / m ³ , or Between 35 kg / m ³ and 80 kg / m ³ and the isocyanate index is between 60 and 110, or Between 200 kg / m ³ and 300 kg / m ³ and the isocyanate index between 75 and 120. 15. Use of PUR flexible foams according to claim 13 or 14 for the production of furniture upholstery, textile inserts, mattresses, automobile seats, Headrests, armrests, sponges and components, as well as seat and dashboard trim.