WO2005000954A1

WO2005000954A1 - Flame-retardant soot-containing polyurethane foams

Info

Publication number: WO2005000954A1
Application number: PCT/EP2004/006294
Authority: WO
Inventors: Johan Antonie Wuestenenk
Original assignee: Akzo Nobel N.V.
Priority date: 2003-06-17
Filing date: 2004-06-10
Publication date: 2005-01-06

Abstract

The present invention pertains to a flame-retardant soot-containing polyurethane foam with improved colour comprising (a) carbon particles, (b) one or more oligomeric, halogen-free organophosphorus compounds, and (c) one or more quaternary ammonium compounds.

Description

FLAME-RETARDANT SOOT-CONTAINING POLYURETHANE FOAMS

The present invention relates to flame-retardant soot-containing polyurethane foams, and to a process to make such polyurethane foams.

As is generally known, polyurethane foams tend to ignite and burn as they are exposed to fire or to prolonged high temperatures. To reduce the safety hazards associated with these foams, they are typically flame-proofed by adding one or more flame retardants. Flame retardants are divided roughly into halogenated flame retardants and halogen-free flame retardants. In order to avoid the toxicity produced by acidic gas such as hydrogen bromide and hydrogen chloride in burning which is associated with the use of halogenated compounds, nowadays the use of halogen-free flame retardants is highly preferred.

Hence, in recent years, much attention has been paid to the development of novel halogen-free flame-retardant systems. For example, EP 0 877 048 discloses a fire-resistant resin composition comprising a thermoplastic resin, phyllosilicate hydrate, and one or more flame retardants selected from the group consisting of a nitrogen base flame retardant having no halogen atoms, a phosphorus base flame retardant having no halogens, and a nitrogen- phosphorus base flame retardant having no halogen atoms. , WO 01/18088 describes a polyurethane foam that contains an effective amount for flame retardancy of a flame-retardant blend comprising a non-oligomeric, non-halogenated organophosphorus flame retardant adapted for use in a polyurethane foam formulation, and an oligomeric organophosphorus flame retardant having a phosphorus content of not less than about 10% by weight and at least three phosphorus atom-containing units therein. For many industrial purposes, it is desired to have dark grey or black coloured (flexible) polyurethane foams. Therefore, these foams are often coloured using soot-containing pastes or carbon black. JP 71 010190, for example, describes a process for the preparation of black/grey spongy polyurethane foam comprising the steps of treating a foamable composition containing a polyhydroxy compound, an organic isocyanate, a foaming agent, a catalyst, and a filler, with silica having a particle size of less than 25 μm, and subsequently foaming the composition in the presence of carbon particles as the colouring agent. These dark grey/black coloured polyurethane foams can be flame-proofed by the addition of conventional halogenated flame retardants. However, it was found that when the halogenated flame retardants are replaced by certain halogen-free flame retardants, the dark grey/black colour of the foam fades to light grey, which is highly undesirable.

Hence, it is an object of the present invention to provide a soot-containing polyurethane foam which is flame-retarded with a halogen-free flame retardant having improved colour.

We have now surprisingly found that the colour of a soot-containing polyurethane foam which is flame-retarded with one or more oligomeric, halogen-free phosphorus-containing compounds can be greatly improved by the incorporation of one or more quaternary ammonium compounds.

Accordingly, the present invention relates to a flame-retarded soot-containing polyurethane foam with improved colour comprising (a) carbon particles, (b) one or more oligomeric, halogen-free organophosphorus compounds, and (c) one or more quaternary ammonium compounds. Preferably, the one or more oligomeric, halogen-free organophosphorus compounds are present in an effective amount for flame retardancy, i.e. they are present in such an amount as to produce a soot-containing polyurethane foam which is flame-retarded when compared to foams not comprising the oligomeric compounds. The one or more oligomeric, halogen-free organophosphorus compounds which can be used in accordance with the present invention are of the conventional type. Preferably, they are oligomeric organophosphorus compounds having a phosphorus content of not less than 10% by weight and, in preferred embodiments, comprise at least three phosphate ester units (i.e., at least two phosphate ester repeat units and a phosphate capping unit). The term "oligomeric" as used in relation to the organophosphorus compounds in the polyurethane foam according to the present invention is meant to include mixtures of organophosphorus compounds comprising trimeric, tetrameric and/or up to polymeric species. It is noted that, besides these trimeric, tetrameric and/or up to polymeric species, said mixtures may also comprise monomeric and/or dimeric species.

Preferred oligomeric, halogen-free organophosphorus compounds are selected from the group of organophosphate oligomers represented by the formula (I):

(i)

wherein n, on a number average basis, is at least 2, and preferably at least 3, whereas n, on a number average basis, is at most 500, preferably at most 250, more preferably at most 100, and most preferably at most 50. R is selected from the group consisting of alkyl and hydroxyalkyl, and R' is alkylene. Preferably, R is selected from the group consisting of C1-C24 alkyl, more preferably C2-C10 alkyl, most preferably C₂-C₄ alkyl, and hydroxyalkyl containing preferably 1-24 carbon atoms and 1-10 hydroxy groups, more preferably from 2-10 carbon atoms and 1-4 hydroxy groups, most preferably from 2-4 carbon atoms. R' preferably is a C1-C24 alkylene, more preferably a C2-C10 alkylene, most preferably a C₂-C₄ alkylene. It is noted that said organophosphate oligomers are generally mixtures which may also comprise monomers (i.e. compounds of formula (I) wherein n is 0) and/or dimers (i.e. compounds of formula (I) wherein n is 1), provided that, on a number average basis, n is at least 2 and at most 500, more preferably at least 3 and at most 50.

Especially preferred organophosphate oligomers for use in the flame-retardant polyurethane foam according to the present invention will comprise ethyl and ethylene groups as the alkyl and alkylene moieties.

Preferably, organophosphate oligomers which have an acid number of not more than 2.5 mg KOH/g are used as the flame retardant.

Particularly preferred organophosphate oligomers are those which have a phosphorus content that ranges from 15% to 30% by weight, preferably, 18% to 25% by weight.

In a particularly preferred embodiment, the product FYROL^® PNX ex Akzo Nobel Chemicals Inc. is used as the flame-retardant component in the polyurethane foam according to the present invention. Said product is an oligomeric phosphate ester (CAS # 184538-58-7) of the formula (I), wherein n typically ranges between 1 and 20 but wherein n, on a number average basis, is 6 or 7, R is ethyl, and R' is ethylene. This preferred product has a phosphorus content of about 19 wt% and a viscosity at 25°C of between about 500 and about 2,500 mPa.s.

The organophosphate oligomers of the general formula (I) can be formed in a conventional way. For example, as described in US 4,382,042, they can be formed by reacting phosphorus pentoxide with a selected trialkyl phosphate (e.g. triethyl phosphate) to form a polyphosphate ester containing P-O-P bonds, which is then reacted with an epoxide (e.g. ethylene oxide) to form the desired product. It is noted that the term organophosphate oligomers used throughout this document is meant not only to include substantially pure organophosphate oligomers, but also organophosphonate/organophosphate oligomers comprising trimeric, tetrameric and/or up to polymeric species. Besides these trimeric, tetrameric and/or up to polymeric species, these organophosphonate/- organophosphate oligomers may also comprise monomeric and/or dimeric species. Furthermore, mixtures of organophosphate oligomers and organophosphonate/organophosphate oligomers can be used as flame retardants in the polyurethane foam according to the present invention. Preferably, said organophosphonate/organophosphate oligomers are compounds of the general formula (II): o o II II O- -p-o-R'-o- -P-Y I Jn X OR (II)

wherein n, on a number average basis, is at least 2, and preferably at least 3, whereas n, on a number average basis, is at most 500, preferably at most 250, more preferably at most 100, and most preferably at most 50. R is selected from the group consisting of alkyl and hydroxyalkyl, R' is alkylene, X for each repeating unit is independently selected from OR and R, and Y is selected from OR and R, with the proviso that at least one X or Y in the compound according to formula (II) is R. R is preferably selected from the group consisting of C1-C24 alkyl, more preferably C2-C10 alkyl, most preferably C2-C₄ alkyl, and hydroxyalkyl containing preferably 1-24 carbon atoms and 1-10 hydroxy groups, more preferably from 2-10 carbon atoms and 1-4 hydroxy groups, most preferably from 2-4 carbon atoms. R' is preferably a C₁-C2₄ alkylene, more preferably a C₂-C₁₀ alkylene, most preferably a C2-C₄ alkylene. It is again noted that said organophosphonate/organophosphate oligomers are mixtures which may also comprise monomers (i.e. compounds of formula (II) wherein n is 0) and/or dimers (i.e. compounds of formula (II) wherein n is 1), provided that, on a number average basis, n is at least 2 and at most 500, preferably at least 3 and at most 50.

A representative and commercially available example of an additive of this type is FYROL^® 51 ex Akzo Nobel Chemicals Inc.

The amount of the one or more oligomeric, halogen-free organophosphorus compounds which are present in the soot-containing flame-retardant polyurethane foam according to the invention preferably is an effective amount for flame-retardancy and this effective amount depends on the density of the foam. In general, the higher the density, the less flame-retardant additive will be required to achieve the desired flame-retarding effect. For example, for a polyurethane foam of about 40 kg/m³, preferably between 2 and 5 parts by weight of oligomeric halogen-free organophosphorus compounds are used per 100 parts by weight of the polyol in the final polyurethane foam (percent by weight on polyol, polyol%w/w). For a polyurethane foam of about 30 kg/m³, preferably between 4 and 8 parts by weight of oligomeric halogen-free organophosphorus compounds are used per 100 parts by weight of the polyol in the final polyurethane foam (percent by weight on polyol, polyol%w/w), whereas for a polyurethane foam of about 25 kg/m³, preferably between 8 and 11 parts by weight of oligomeric halogen-free organophosphorus compounds are used per 100 parts by weight of the polyol in the final polyurethane foam (percent by weight on polyol, polyol%w/w), and for a polyurethane foam of about 22 kg/m³, preferably between 10 and 13 parts by weight per 100 parts by weight of the polyol are applied. Normally, the one or more oligomeric, halogen-free organophosphorus compounds are present in an amount ranging from 1 to 30 parts by weight per 100 parts by weight of the polyol in the final polyurethane foam.

The one or more quaternary ammonium compounds which can be used in accordance with the present invention include all conventional quaternary ammonium compounds, which can be prepared using conventional quaternisation procedures. Preferably, quaternary ammonium compounds which are non-halogenated are used. More preferably, the reaction products of a tertiary amine and di(m)ethylsu!phate are used. In another preferred embodiment amidopropyl quaternary ammonium compounds and esterified quaternary ammonium compounds are applied. Examples of preferred quaternary ammonium compounds include, but are not limited to, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octadecyltrimethylammonium chloride, cocotrimethylammonium chloride, oleyltrimethylammonium chloride, tallow- trimethylammonium chloride, tetradecylbenzyldimethylammonium chloride, octadecylbenzyldimethylammonium chloride, cocobenzyldimethylammonium chloride, tallowbenzyldimethylammonium chloride, hydrogenated tallowbenzyl- dimethylammonium chloride, didecyldimethylammonium chloride, dialkyl- dimethylammonium chloride, dicocodimethylammonium chloride, oleyltrimethyl- ammonium/dicocodimethylammonium chloride, ditallowdimethylammonium chloride, (partially) hydrogenated ditallowdimethylammonium chloride, N,N,N',N'-pentamethyl-N-tallow-1 ,3-propanediammonium dichloride, cocobis(2- hydroxyethyl)methylammonium chloride, polyoxyethylene (15) cocomethyl- ammonium chloride, oleylbis(2-hydroxyethyl)methylammonium chloride, polyoxyethylene (15) stearylmethylammonium chloride, distearyldimethyl- ammonium chloride, and their corresponding methosulphate or ethosulphate salts. The most preferred quaternary ammonium compounds are methosulphate and ethosulphate quaternary ammonium compounds. In a particularly preferred embodiment, Arquad^® 2C-75, Arquad^® 2.10-40, Arquad^® MCB, or Arquad^® 2 HT-75 ex Akzo Nobel N.V. is employed as the quaternary ammonium compound in the polyurethane foam according to the present invention. Other preferred products include the methosulphate and ethosulphate quaternary ammonium salts Empigen^® CM ex Huntsman, Marlosoft^® IQ 90 ex Sasol, Barquat^® CME-35 ex Lonza, Carosoft^® CFI-90 ex Lonza, Pentonium^® 6 ex Stepan, and Larostat^® 264A ex PPG. Preferred amidopropyl quaternary ammonium salts include Schercoquat^® FAOS, Schercoquat^® IEP, Schercoquat^® IIS, Schercoquat^® ROAS, Schercoquat^® SAS, Schercoquat^® SOAS, and Schercoquat^® WOAS, ex Scher Chemicals, Caflon^® CM ex Univar.

Preferably, the amount of the one or more quaternary ammonium compounds in the soot-containing polyurethane foam according to the present invention is at least the amount necessary to obtain a dark grey or black coloured polyurethane foam. The amount of the one or more quaternary ammonium compounds in the soot-containing flame-retardant polyurethane foam according to the invention necessary to effectuate an improved colour of the soot- containing polyurethane foam preferably does not exceed 1 part by weight, more preferably 0.8 parts by weight, even more preferably 0.6 parts by weight, and most preferably 0.3 parts by weight, per 100 parts by weight of the polyol in the final polyurethane foam (percent by weight on polyol, polyol%w/w). Preferably, the amount of the one or more quaternary ammonium compounds present in the soot-containing flame-retardant polyurethane foam is at least 0.001 part by weight, more preferably at least 0.005 parts by weight, and most preferably at least 0.01 part by weight, per 100 parts by weight of the polyol in the final polyurethane foam (percent by weight on polyol, polyol%w/w).

The term "soot" used throughout this document is meant to include all colorants which comprise carbon particles. Preferably, the polyurethane foam according to the invention is coloured using soot-containing compounds or pastes which are compatible with polyether-based polyurethane systems, and more preferably, products compatible with polyester and polyether polyurethane systems. Preferred products include Isopur^® SU 08917, Isopur^® SE 20590, Isopur^® 20500, Isopur^® 20560, ex ISL Chemie; Moltopren^® AU 01 , Bayflex^® N ex Rhein Chemie; Black Repiplast^®/PU 99575, Black Repitan^®/IN "99430" ex Repi S.p.A.; Peka^® black 100 ex Peka; and soot paste in DDP or in PhosFlex ex Prism Chemicals. In a particularly preferred embodiment, the soot-containing paste Isopur^® SU 08917/9110 or Isopur^® SE 20590/9124 ex ISL Chemie or Black Repiplast^®/PU 99575 ex Repi S.p.A. is employed to colour the polyurethane foam according to the present invention. Isopur^® SU 08917/9110 and Isopur^® SE 20590/9124 are based on a polyester polyol and comprise 12.5-20 wt% of 2-(2-butoxyethoxyl)-ethanol, whereas Black Repiplast^®/PU 99575 is a carbon black dispersion in low viscosity polymeric carriers and additives.

Preferably, the polyurethane foam according to the invention comprises an amount of the soot-containing compound(s) such that an effective amount of carbon particles is present in the polyurethane foam. Thus, preferably, at least an amount of soot-containing compound(s) is present which is necessary to obtain a dark grey or black coloured polyurethane foam. The amount of soot- containing compounds or pastes present in the soot-containing fiame-retardant polyurethane foam according to the invention preferably is at most 8 parts by weight, more preferably at most 6 parts by weight, even more preferably at most 4 parts by weight, and most preferably at most 2 parts by weight, per 100 parts by weight of the polyol in the final polyurethane foam. The amount of soot in the polyurethane foam is at least 0.01 part by weight, more preferably at least 0.05 parts by weight, and most preferably at least 0.1 part by weight, per 100 parts by weight of the polyol in the final polyurethane foam.

If necessary, the soot-containing flame-retardant polyurethane foam of the present invention may further contain known additive components, as long as the effects of the present invention are not adversely affected. Examples include anti-oxidants, weather-resistant agents, metal deactivators, lubricants, crystallisation nucleus agents, fillers, blooming inhibitors, anti-blocking agents, cloud inhibitors, adhesives, colorants, anti-static agents, absorbers for oxygen and carbon dioxide, and/or gas absorbents. The soot-containing flame-retardant polyurethane foam with improved colour according to the present invention preferably is a flexible polyurethane foam. Preferred flexible foams can be made as disclosed in US 3,956,200. The actual incorporation of the soot-containing compounds or pastes, the one or more quaternary ammonium compounds, and the one or more oligomeric halogen- free phosphorus compounds in the preparation of flexible polyurethane foams may be accomplished by means of a variety of procedures including the preliminary admixture of these components with the polyol reagent prior to the polymerisation reaction, or these components may be introduced as separate streams to a foam machine mixing head. In a particularly preferred embodiment according to the present invention, the soot-containing flame-retardant polyurethane foam is prepared by reacting a polyol with an isocyanate in the presence of carbon particles, an effective amount for flame retardancy of one or more oligomeric, halogen-free organophosphorus compounds, and one or more quaternary ammonium compounds.

As examples of organic polyisocyanates which can be employed to make the polyurethane foams may be mentioned: toluene-2,4-diisocyanate; toluene-2,6- diisocyanate; 4-methoxy-1 ,3-phenylene diisocyanate; diphenyl methane-4,4'- diisocyanate; 4-chloro-1 ,3-phenylene-diisocyanate; 4-isopropyl-1 ,3-phenylene- diisocyanate; 4-ethoxy-1 ,3-phenylene-diisocyanate; 2,4-diisocyanate-diphenyl ether; 3,3'-dimethyl-4,4'-diisocyanatodiphenyl methane; mesitylene diisocyanate; durylene diisocyanate; 4,4'-methylene-bis(phenyl isocyanate); benzidine diisocyanate; o-nitrobenzidine diisocyanate; 4,4'-diisocyanato- dibenzyl; 3,3'-bitolylene-4,4'-diisocyanate; 1 ,5-naphthalene diisocyanate; tetramethylene diisocyanate; hexamethylene diisocyanate; decamethylene diisocyanate; toluene-2,4,6-triixocyanate; tritolylmethane triisocyanate; 2,4,4'- triisocyanatodiphenyl ether; the reaction product of toluene diisocyanate with trimethylol propane; and the reaction product of toluene diisocyanate with 1 ,2,6- hexane triol. Alternatively, prepolymers made by reacting one or more of the above polyisocyanates with a polyhydroxy compound such as a polyester having terminal hydroxyl groups, a polyhydric alcohol, glycerides or hydroxy-containing glycerides, etc., can be used as the polyisocyanate. The prepolymers should have terminal isocyanate groups. To ensure their presence it is frequently desirable to employ an excess of 5% or more of the polyisocyanate in forming the prepolymer. Typical examples of such prepolymers having isocyanate end groups are those formed from toluene diisocyanate and polyhydroxy compounds. In most cases, a mixture of 80% of the 2,4-isomer and 20% of the 2,6-isomer of toluene diisocyanate is employed in making these prepolymers. Thus, use can be made of the prepolymers resulting from the reaction between toluene diisocyanate and castor oil, blown tung oil, blown linseed oil or blown soya oil, and of toluene diisocyanate and the polyester of ethylene glycol, propylene glycol, and adipic acid.

Examples of suitable polyols are polyethylene glycols; polypropylene glycols; ethylene glycol; diethylene glycol; tripropylene glycol; 1 ,4-butane diol; thiodiglycol; glycerol; trimethylol ethane; trimethylol propane; ether triols from glycerin and propylene oxide; ether-containing triols from 1 ,2,6-hexane triol and propylene oxide; sorbitol-propylene oxide adducts; pentaerythritol-propylene oxide adducts; trimethylol phenol; oxypropylated sucrose; triethanolamine; pentaerythirol; diethanolamine, castor oil; blown linseed oil; blown soya oil; N,N,N',N'-tetrakis (2-hydroxyethyl) ethylene diamine; N,N,N',N'-tetrakis (2- hydroxypropyl) ethylene diamine; mixed ethylene glycol-propylene glycol adipate resin; polyethylene adipate phthalate, and polyneopentylene sebacate.

In preparing the foamed polyurethanes, use can be made of any of the conventional basic catalysts, for example N-methyl morpholine, N-ethyl morpholine, 1 ,2,4-trimethyl piperazine, trimethyl amine, triethyl amine, tributyl amine, and other trialkyl amines, the esterification product of adipic acid and diethyl ethanolamine, triethyl amine citrate, 3-morpholinopropinoamide, 1 ,4- bis(2-hydroxypropyI)-2-methy! piperazine, 2-diethyl aminoacetamide, 3-diethyl aminopropionamide, diethyl ethanolamine, triethylene diamine, N,N, N',N'- tetrakis (2-hydroxypropyl) ethylene diamine N,N'-dimethyl piperzine, N,N- dimethyl hexahydroaniline, tribenzylamine, and sodium phenolate. Also applicable are tin compounds, e.g., hydrocarbon tin acylates such as dibutyl tin dilaurate, dibutyl tin diacetate, dibutyl tin dioxtoate, tributyl tin monolaurate, dibutyl tin diacetate, dioxtyl tin diacetate, dilauryl tin diacetate, dibutyl tin maleate, and alkyl tin alkoxides, e.g., dibutyl tin diethoxide, dibutyl tin dimethoxide, diethyl tin dibutoxide, as well as other tin compounds, e.g., octylstannoic acid, trimethyl tin hydroxide, trimethyl tin chloride, triphenyl tin hydride, triallyl tin chloride, tributyl tin fluoride, dibutyl tin dibromide, bis(carboethoxymethyl) tin diiodide, tributyl tin chloride, trioctyl tin acetate, butyl tin trichloride, or octyl tin tris(thiobutoxide), dimethyl tin oxide, dibutyl tin oxide, dioctyl tin oxide, diphenyl tin oxide, stannous octoate, and stannous oleate.

Conventional surfactants can be added to the soot-containing flame-retardant polyurethane composition to influence the foam structure of the resulting foam in an amount of 2% or less, e.g. 0.6% by weight of the composition. The preferred surfactants are silicones, e.g., polydimethyl siloxane having a viscosity of 3 to 100 mPa.s (centistokes), triethoxydimethyl polysiloxane, molecular weight 850, copolymerised with a dimethoxypolyethylene glycol having a molecular weight of 750.

The soot-containing flame-retardant polyurethane foams according to the present invention may be utilised in all end use applications for such foams. Preferably, the foams are used in a foam covered by textile, e.g., in the automotive industry.

The present invention is elucidated by means of the following non-limiting Examples. Example 1

A polyurethane foam formulation was prepared from the following ingredients: Polyol Caradol^® SC 48.03 100 parts by weight Water 4.6 php Amine catalysts Dabco^® BLV 0.27 php Cell stabiliser Tegostab^® B8232 1.0 php Stannous Octoate Dabco^® T-9 0.20 php Toluene diisocyanate TDI T-80 index 110 php (wherein php = parts by weight per 100 parts by weight of the polyol in the final polyurethane foam formulation)

Formulation A:

A polyurethane foam was prepared from the above-mentioned ingredients, while Isopur^® SU 08917/9110 was used as colorant (see TABLE 1) and the halogenated organophosphorus flame retardant Fyrol^® A 301 was used as a flame retardant. The resulting foam was dark grey/black in colour.

Formulation B: A polyurethane foam was prepared from the above-mentioned ingredients, while Isopur^® SU 08917/9110 was used as colorant (see TABLE 1). The halogen-free organophosphorus flame retardant Fyrol^® PNX was used as a flame retardant. The resulting foam was light grey in colour.

Formulation C:

A polyurethane foam was prepared from the above-mentioned ingredients, with Isopur^® SU 08917/9110 as colorant (see TABLE 1). The halogen-free organophosphorus flame retardant Fyrol^® PNX was used as a flame retardant. The quaternary ammonium compound Arquad^® 2C-75 was added to the polyurethane foam formulation. The resulting foam was dark grey/black in colour. Formulation D:

A polyurethane foam was prepared from the above-mentioned ingredients, with Isopur^® SE 20590/9124 as colorant (see TABLE 1). The halogen-free organophosphorus flame retardant Fyrol^® PNX was used as a flame retardant. Without quaternary ammonium compound added to the polyurethane foam formulation, the colour was light grey, whereas when the quaternary ammonium compound Arquad^® 2C-75 was added to the polyurethane foam formulation, the resulting foam was dark grey/black in colour.

Formulation E:

A polyurethane foam was prepared from the above-mentioned ingredients, with Isopur^® SU 08917/9110 as colorant (see TABLE 1). The halogen-free organophosphorus flame retardant Fyrol^® PNX was used as a flame retardant. The quaternary ammonium compound CAFLON^® CM was added to the polyurethane foam formulation. The resulting foam was dark grey/black in colour.

TABLE 1

Claims

1. A flame-retardant soot-containing polyurethane foam with improved colour comprising (a) carbon particles, (b) one or more oligomeric, halogen-free organophosphorus compounds, and (c) one or more quaternary ammonium compounds.

2. A polyurethane foam according to claim 1 wherein the one or more oligomeric, halogen-free organophosphorus compounds are selected from the group consisting of organophosphate and/or organophosphonate oligomers represented by the formula: o O II II RO- -P-O-R'-O P-Y I Jn x OR wherein n, on a number average basis, ranges from 2 to 500, R is selected from the group consisting of alkyl and hydroxyalkyl, R' is alkylene, X for each repeating unit is independently selected from OR and R, and Y is selected from OR and R.

3. A polyurethane foam according to claim 2 wherein the oligomeric, halogen-free organophosphorus compound is selected from the group of organophosphate oligomers represented by the formula:

wherein n, on a number average basis, can range from 2 to 500, R is selected from the group consisting of alkyl and hydroxyalkyl, and R' is alkylene, and wherein R preferably is ethyl and R' preferably is ethylene.

4. Polyurethane foam according to any one of the preceding claims wherein the quaternary ammonium compound is selected from the group consisting of dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octadecyl- trimethylammonium chloride, cocotrimethylammonium chloride, oleyltrimethylammonium chloride, tallowtrimethylammonium chloride, tetradecylbenzyldimethylammonium chloride, octadecylbenzyldimethyl- ammonium chloride, cocobenzyldimethylammonium chloride, tallow- benzyldimethylammonium chloride, (partially) hydrogenated tallow- benzyldimethylammonium chloride, didecyldimethylammonium chloride, dialkyldimethylammonium chloride, dicocodimethylammonium chloride, oleyltrimethylammonium/dicocodimethylammonium chloride, ditallowdimethylammonium chloride, hydrogenated ditallowdimethylammonium chloride, N,N,N',N'-pentamethyl-N-tallow-1 ,3-propanediammonium dichloride, cocobis(2-hydroxyethyl)methylammonium chloride, polyoxyethylene (15) cocomethylammonium chloride, oleylbis(2-hydroxy- ethyl)methylammonium chloride, polyoxyethylene (15) stearylmethyl- ammonium chloride, distearyldimethylammonium chloride, and their corresponding methosulphate or ethosulphate salts.

5. A polyurethane foam according to any one of the preceding claims wherein the quaternary ammonium compound is a conventional quaternary ammonium compound which does not comprise a halogen atom.

6. A polyurethane foam according to any one of the preceding claims wherein the one or more oligomeric, halogen-free organophosphorus compounds are present in an amount ranging from 1 to 30 parts by weight per 100 parts by weight of the polyol in the final polyurethane foam, and wherein the one or more quaternary ammonium compounds are present in an amount ranging from 0.01 to 2.0 parts by weight per 100 parts by weight of the polyol in the final polyurethane foam.

7. Use of one or more quaternary ammonium compounds for improving the colour of a soot-containing polyurethane foam which is flame-retarded with an effective amount of one or more oligomeric, halogen-free organophosphorus compounds having a phosphorus content of not less than about 10% by weight.

8. Composition comprising one or more oligomeric, halogen-free organophosphorus compounds and one or more quaternary ammonium compounds.

9. Process to make the foams of claims 1-6 wherein a polyol is reacted with an isocyanate in the presence of carbon particles, an effective amount for flame retardancy of one or more oligomeric, halogen-free organophosphorus compounds, and one or more quaternary ammonium compounds.