Halogen-free poly(alkylene phosphates)

Abstract

The present invention relates to halogen-free oligomer mixtures of poly(alkylene phosphates), production of these and use as flame retardants, and also to flame-retardant polyurethanes comprising halogen-free oligomer mixtures as flame retardants.

Claims

1. An oligomer mixture consisting essentially of at least three different poly(alkylene phosphates) of the formula (I), ##STR00015## in which R.sup.1, R.sup.2, R.sup.3 and R.sup.4 mutually independently are a straight-chain or branched C.sub.1-C.sub.8-alkyl moiety or a straight-chain or branched C.sub.1-C.sub.4-alkoxyethyl moiety, A is a straight-chain, branched and/or cyclic C.sub.4-C.sub.20-alkylene moiety, or a moiety of the formula CH.sub.2CHCHCH.sub.2, a moiety of the formula CH.sub.2CCCH.sub.2, a moiety of the formula CHR.sup.5CHR.sup.6(OCHR.sup.7CHR.sup.8).sub.a, in which R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are mutually independently methyl or H, wherein at least one of R.sup.5, R.sup.6, R.sup.7 and R.sup.8 is H, a moiety of the formula CHR.sup.5CHR.sup.6S(O).sub.bCHR.sup.7CHR.sup.8, or a moiety of the formula (CHR.sup.5CHR.sup.6O).sub.cR.sup.9(OCHR.sup.7CHR.sup.8).sub.d, in which R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are mutually independently H or mehtyl, and a is an integer from 1 to 5, b is an integer from 0 to 2, c and d are mutually independently an integer from 1 to 5, and R.sup.9 is a moiety of the formula CH.sub.2CHCHCH.sub.2, a moiety of the formula CH.sub.2CCCH.sub.2, a 1,2-phenylene moiety, a 1,3-phenylene moiety, a 1,4-phenylene moiety, a moiety of the formula (II) ##STR00016## a moiety of the formula (III) ##STR00017## a moiety of the formula (IV) ##STR00018## a moiety of the formula C(O)R.sup.12C(O), where R.sup.10 and R.sup.11 are mutually independently respectively H or C.sub.1-C.sub.4-alkyl or R.sup.10 and R.sup.11 together are an optionally alkyl-substituted ring having from 4 to 8 carbon atoms, and R.sup.12 is a straight-chain, branched and/or cyclic C.sub.2-C.sub.8-alkylene moiety, a 1,2-phenylene moiety, a 1,3-phenylene moiety, or a 1,4-phenylene moiety, and n is an integer from 0 to 100, with the proviso that the at least three poly(alkylene phosphates) of the formula (I) differ from one another at least in the number n of the repeating units, and an average number of the repeating units n of the at least three poly(alkylene phosphates) of the formula (I) is greater than 1.10 and smaller than 2.00.

2. The oligomer mixture according to claim 1, wherein: R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are identical and are ethyl, n-propyl, isopropyl, n-butyl, isobutyl or n-butoxyethyl, A is a straight-chain C.sub.4-C.sub.6-alkylene moiety, or a moiety of the formulae ##STR00019## or a moiety CHR.sup.5CHR.sup.6(OCHR.sup.7CHR.sup.8).sub.a, in which a is an integer from 1 to 2 and R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are identical and are H, or a moiety (CHR.sup.5CHR.sup.6O).sub.cR.sup.9(OCHR.sup.7CHR.sup.8).sub.d, in which c and d are mutually independently an integer from 1 to 2, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are identical and are H, and R.sup.9 is a moiety of the formula (II), where R.sup.10 and R.sup.11 are identical and are methyl, and n is an integer from 0 to 20.

3. The oligomer mixture according to claim 1, wherein the average number of the repeating units n is greater than 1.20 and smaller than 1.90.

4. The oligomer mixture according to claim 1, wherein the oligomer mixture is halogen-free.

5. The oligomer mixture according to claim 1, wherein the oligomer mixture has a dynamic viscosity of 20 to 1000 mPas at 23 C.

6. A process for producing an oligomer mixture according to claim 1, the process comprising: reacting in a first stage, a dihydroxy compound of the formula HO-A-OH, in which A is defined as in claim 1, with phosphorus oxychloride POCl.sub.3, where the amount used of dihydroxy compound of the formula HO-A-OH per mole of phosphorus oxychloride is more than 1.0 mol and less than 2.0 mol to produce a resultant mixture of oligomeric chlorophosphates of the formula (VIII) ##STR00020## in which n is an integer from 0 to 100; and reacting in a second stage, the mixture of oligomeric chlorophosphates with at least one monohydroxy compound of the formula
M-OH(IX), in which M is R.sup.1, R.sup.2, R.sup.3 or R.sup.4, and the definitions of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are those stated in claim 1.

7. Flame retardant preparations comprising at least one oligomer mixture according to claim 1, one or more flame retardants B) differing from the oligomer mixture, and optionally one or more auxiliaries C).

8. The flame retardant preparation according to claim 7, wherein the flame retardant B) is selected from the group consisting of triethyl phosphate, triphenyl phosphate, diphenyl cresyl phosphate, tricresyl phosphate, isopropylated or butylated aryl phosphates, bisphenol A bis(diphenyl phosphate), resorcinol bis(diphenyl phosphate), neopentyl glycol bis(diphenyl phosphate), tris(chloroisopropyl) phosphate, tris(dichloropropyl) phosphate, dimethyl methanephosphonate, diethyl ethanephosphonate, dimethyl propanephosphonate, diethyl phosphinic acid derivatives and diethyl phosphinic acid salts, oligomeric phosphates or phosphonates, hydroxylated phosphorus compounds, 5,5-dimethyl-1,3,2-dioxaphosphorinane 2-oxide derivatives, 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) and its derivatives, ammonium phosphate, ammonium polyphosphate, melamine phosphate, melamine polyphosphate, melamine, melamine cyanurate, alkyl ester of a tetrabromobenzoic acid, bromine-containing diols produced from tetrabromophthalic anhydride, bromine-containing polyols, bromine-containing diphenyl ethers, aluminium hydroxide, boehmite, magnesium hydroxide, expandable graphite and clay minerals.

9. Flams-retardant polyurethanes comprising at least one oligomer mixture according to claim 1.

10. The flame-retardant polyurethanes according to claim 9, wherein the flame-retardent polyurethanes comprise polyurethane foams.

11. A process for producing flame-retardant polyurethanes according to claim 9, the process comprising reacting at least one organic polyisocyanate with at least one compound which has at least two hydrogen atoms reactive towards isocyanates in the presence of at least one oligomer mixture according to claim 1.

12. The process according to claim 11, further comprising using 3 to 25 parts by weight of oligomer mixture for every 100 parts by weight of compound having at least two hydrogen atoms reactive towards isocyanates.

13. The process according to claim 11, wherein the compound having at least two hydrogen atoms reactive towards isocyanates comprises a polyether polyol.

14. The process according to claim 11, wherein the compound having at least two hydrogen atoms reactive towards isocyanates comprises a polyester polyol.

15. Mouldings, lacquers, adhesives, coatings, adhesion promoters and fibres comprising polyurethanes according to claim 9.

16. An oligomer mixture comprising poly(alkylene phosphates), wherein the poly(alkylene phosphates) in the mixture consist of at least three different poly(alkylene phosphates) of the formula (I) ##STR00021## in which R.sup.1, R.sup.2, R.sup.3 and R.sup.4 mutually independently are a straight-chain or branched C.sub.1-C.sub.8-alkyl moiety or a straight-chain or branched C.sub.1-C.sub.4-alkoxyethyl moiety, A is a straight-chain, branched and/or cyclic C.sub.4-C.sub.20-alkylene moiety, or a moiety of the formula CH.sub.2CHCHCH.sub.2, a moiety of the formula CH.sub.2CCCH.sub.2, a moiety of the formula CHR.sup.5CHR.sup.6(OCHR.sup.7CHR.sup.8).sub.a, a moiety of the formula CHR.sup.5CHR.sup.6S(O).sub.bCHR.sup.7CHR.sup.8, or a moiety of the formula (CHR.sup.5CHR.sup.6O).sub.cR.sup.9(OCHR.sup.7CHR.sup.8).sub.d, in which a is an integer from 1 to 5, b is an integer from 0 to 2, c and d are mutually independently an integer from 1 to 5, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are mutually independently H, and R.sup.9 is a moiety of the formula CH.sub.2CHCHCH.sub.2, a moiety of the formula CH.sub.2CCCH.sub.2, a 1,2-phenylene moiety, a 1,3-phenylene moiety, a 1,4-phenylene moiety, a moiety of the formula (II) ##STR00022## a moiety of the formula (III) ##STR00023## a moiety of the formula (IV) ##STR00024## a moiety of the formula C(O)R.sup.12C(O), where R.sup.10 and R.sup.11 are mutually independently respectively H or C.sub.1-C.sub.4-alkyl or R.sup.10 and R.sup.11 together are an optionally alkyl-substituted ring having from 4 to 8 carbon atoms, and R.sup.12 is a straight-chain, branched and/or cyclic C.sub.2-C.sub.8-alkylene moiety, a 1,2-phenylene moiety, a 1,3-phenylene moiety, or a 1,4-phenylene moiety, and n is an integer from 0 to 100, with the proviso that the at least three poly(alkylene phosphates) of the formula (I) differ from one another at least in the number n of the repeating units, and an average number of the repeating units n of the at least three poly(alkylene phosphates) of the formula (I) is greater than 1.10 and smaller than 2.00.

17. The oligomer mixture according to claim 16, wherein the oligomer mixture consists of at least three different poly(alkylene phosphates) of the formula (I).

18. The oligomer mixture according to claim 1, wherein A is a moiety CHR.sup.5CHR.sup.6(OCHR.sup.7CHR.sup.8).sub.a, in which a is an integer from 1 to 2 and R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are identical and are H.

Description

EXAMPLES

General Synthesis Specification for the Oligomer Mixtures (Synthesis Examples S1 to S5)

(1) The amount (parts by weight) of phosphorus oxychloride stated in Table 1 was charged to a reactor with stirrer, dropping funnel, reflux condenser and vacuum equipment. The temperature of the phosphorus oxychloride was controlled to from 10 to 20 C. The amount of diethylene glycol stated in Table 1 was added dropwise under a vacuum of from 500 to 700 mbar. Once the dropwise addition had ended, the pressure was further lowered to a final value of from 5 to 15 mbar, and the temperature was raised to from 20 to 30 C. This gave an almost colourless, liquid residue.

(2) The amount of ethanol stated in Table 1 was used as initial charge at from 20 to 30 C. in another reactor with stirrer, dropping funnel and reflux condenser, and the residue obtained above was admixed. Stirring of the mixture was continued at from 20 to 30 C. until the reaction was complete, and the mixture was then neutralized via addition of concentrated sodium hydroxide solution. A sufficient amount of dichloromethane and water was then added to give two clear liquid phases. These were separated, and distillation was used to free the organic phase from the dichloromethane, excess ethanol and water. This gave a residue of the oligomer mixtures according to the invention in the form of colourless liquids. The viscosities of the resultant products were determined at 23 C. with a commercially available falling-sphere viscometer, and are listed in Table 1.

(3) Determination of the Average Number of the Repeating Units n of the Molecules Corresponding to the Formula I in the Oligomer Mixture

(4) Analysis by gel permeation chromatography (GPC) showed that the resultant products were oligomer mixtures. The number-average molar masses M.sub.n of the oligomer mixtures were determined by GPC with tetrahydrofuran as eluent against polystyrene standards by a method based on DIN 55672-1:2007-08. The average number of the repeating units n of the poly(alkylene phosphates) corresponding to the formula (I) present in an oligomer mixture was calculated by the following formula from the number-average molar mass M.sub.n measured:
n=(M.sub.nM.sub.E)/M.sub.R where n: average number of repeating units of the poly(alkylene phosphates) of the foimula (I) present in the oligomer mixture, M.sub.n: number-average molar mass in g/mol determined by gel permeation chromatography, M.sub.E: sum of the molar masses of the end groups in g/mol and M.sub.R: molar mass of the repeating unit in g/mol.

(5) For the oligomer mixtures of poly(alkylene phosphates) of the formula (I) where R.sup.1R.sup.2R.sup.3R.sup.4=ethyl and A=CH.sub.2CH.sub.2OCH.sub.2CH.sub.2, M.sub.E=182.16 g/mol and M.sub.R=194.14 g/mol. Table 1 lists the results.

(6) TABLE-US-00001 TABLE 1 Raw materials and parts by weight used for producing oligomer mixtures of poly(alkylene phosphates) of the formula (I) where R.sup.1 = R.sup.2 = R.sup.3 = R.sup.4 = ethyl and A = CH.sub.2CH.sub.2OCH.sub.2CH.sub.2 for Synthesis Examples S1 to S5 and properties Example S1 S2 S3 S4 S5 Diethylene glycol 235.3 428.2 466.4 118.7 118.7 Phosphorus 476.9 736.0 1214 306.7 269.9 oxychloride Ethanol 1225 2230 2428 618.2 618.2 Viscosity [mPas] 190 1423 40 58 85 M.sub.n 592 655 429 462 495 n 2.11 2.44 1.27 1.44 1.61 According to the no no yes yes yes invention
Production of Flexible Polyurethane Foams

(7) TABLE-US-00002 TABLE 2 Raw materials used for producing flexible polyether foams for the compositions of Inventive Examples IE2, IE2 and IE3, and also of the Non- inventive Comparative Examples CE1 to CE6 (according to Table 4) Component Function Description A Polyol Arcol 1105 (Bayer MaterialScience), polyether polyol with OH number 56 mg KOH/g B Blowing agent Water C Catalyst Addocat 108 (Rhein Chemie), 70% solution of bis(2-dimethylaminoethyl) ether in dipropylene glycol D Catalyst Addocat SO (Rhein Chemie), tin(II) 2-ethylhexanoate E Stabilizer Tegostab B 8232 (Degussa), silicone stabilizer F1 Flame retardant Tris(2,3-dichloroisopropyl) phosphate, TDCP F2 Flame retardant Diphenyl cresyl phosphate F3 Flame retardant Diethylene glycol bis(diethyl phosphate) according to EP 1 746 129 A1 F4 Flame retardant Fyrol PNX from ICL-IP (oligoineric phosphate ester of the formula I where R.sup.1 = R.sup.2 = R.sup.3 = R.sup.4 = ethyl and A = ethylene, CAS Reg. No. 184538-58-7), M.sub.n = 640 g/mol from GCP (see above); formula (I) gives n = 3.01; viscosity 1241 mPas at 23 C. F5 Flame retardant Product from Synthesis Example S1, not according to the invention F7 Flame retardant Product from Synthesis Example S3, according to the invention F8 Flame retardant Product from Synthesis Example S4, according to the invention F9 Flame retardant Product from Synthesis Example S5, according to the invention G Diisocyanate Desmodur T 80 (Bayer MaterialScience), tolylene diisocyanate, isomer mixture
Production of Flexible Polyether Foams

(8) Table 2 states the raw materials for producing flexible polyether foams, Table 4 states the nature and amount of the components which, with the exception of the diisocyanate (component G), were mixed to give a homogeneous mixture. The diisocyanate was then added and incorporated by brief vigorous stirring. The envelope density of the flexible polyurethane foam obtained after a cream time of from 15 to 20 s and a full rise time of from 170 to 200 s was 33 kg/m.sup.3. All of the experiments gave uniformly fine-pored foams.

(9) TABLE-US-00003 TABLE 3 Raw materials used for producing flexible polyester foams for the compositions of Inventive Examples IE4, IE5 and IE6, and also of the Non-inventive Comparative Examples CE7 to CE13 (according to Table 5) Component Function Description A Polyol Desmophen 2200 B (Bayer MaterialScience), polyester polyol with OH number 60 mg KOH/g B Blowing agent Water C Catalyst Niax A-30(Momentive), amine D Catalyst Addocat 117 (Rhein Chemie), tertiary amine E Stabilizer Tegostab B 8324 (Degussa), silicone stabilizer F1 Flame retardant Tris(2,3-dichlorolsopropyl) phosphate, TDCP, CAS Reg. No. 13674-87-8 F2 Flame retardant Diphenyl cresyl phosphate, CAS Reg. No. 26444-49-5 F3 Flame retardant Diethylene glycol bis(diethyl phosphate) according to EP 1 746 129 A1 F4 Flame retardant Fyrol PNX from ICL-IP (oligotneric phosphate ester of the formula I where R.sup.1 = R.sup.2 = R.sup.3 = R.sup.4 = ethyl and A = ethylene, CAS Reg. No. 184538-58-7), M.sub.n = 640 g/mol from GCP (see above); formula (I) gives n = 3.01; viscosity 1241 mPas at 23 C. F5 Flame retardant Product from Synthesis Example S1 F6 Flame retardant Product from Synthesis Example S2 F7 Flame retardant Product from Synthesis Example S3, according to the invention F8 Flame retardant Product from Synthesis Example S4, according to the invention F9 Flame retardant Product from Synthesis Example S5, according to the invention G Diisocyanate Desmodur T 80 (Bayer MaterialScience), tolylene diisocyanate, isomer mixture H Diisocyanate Desmodur T 65 (Bayer MaterialScience), tolylene diisocyanate, isomer mixture
Production of Flexible Polyester Foams

(10) Table 3 states the raw materials for producing flexible polyester foams. Table 5 states the nature and amount of the components which, with the exception of the two diisocyanates (components G and H), were mixed to give a homogeneous mixture. The two premixed diisocyanates were then added and incorporated by brief vigorous stirring. The envelope density of the flexible polyurethane foam obtained after a cream time of from 10 to 15 s and a full rise time of from 80 to 90 s was 29 kg/m.sup.3. The foam structure of the flexible polyester foams depended on the flame retardants used. It is recorded in Table 5 as uniformly fine-pored (uf) or non-uniformly coarse-pored (nc).

(11) Test Results for Flexible Polyurethane Foams

(12) Determination of Flame Retardancy

(13) The flexible polyurethane foams were tested in accordance with the specifications of the Federal Motor Vehicle Safety Standards FMVSS 302 and allocated to fire classes SE (self-extinguishing), SE/NBR (self-extinguishing/no burning rate), SE/BR (self-extinguishing/with burning rate), BR (burning rate) and RB (rapid burning). The fire tests were carried out five times for each Example. The worst result from each series of five has been given in Table 4 and, respectively, Table 5.

(14) Determination of Fogging

(15) The fogging behaviour of the flexible polyurethane foams was studied in accordance with DIN 75201 B. Table 4 gives the amounts of condensate measured after storage at 100 C. for 16 h.

(16) TABLE-US-00004 TABLE 4 Composition (parts by weight) and test results for Inventive Examples IE1 to IE3 and for Non-inventive Comparative Examples CE1 to CE6 relating to flexible polyether foams Example CE1 CE2 CE3 CE4 CE5 CE6 IE1 IE2 IE3 A 100 100 100 100 100 100 100 100 100 B 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 C 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 D 0.16 0.16 0.16 0.16 0.16 0.16 0.16 0.16 0.16 E 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 F1 6 F2 6 F3 6 F4 6 F5 6 F7 6 F8 6 F9 6 G 40.9 40.9 40.9 40.9 40.9 40.9 40.9 40.9 40.9 FMVSS class RB SE BR SE SE SE SE SE SE Fogging 0.19 0.72 0.59 0.37 0.33 0.21 0.32 0.31 0.28 condensate [mg] in accordance with DIN 75201 B
Evaluation of the Results Relating to Flexible Polyether Foams

(17) In the absence of a flame retardant (Comparative Example CE1) the flexible polyurethane foam is rapidly consumed by burning (FMVSS fire class RB), but exhibits a very low fogging value. A foam with tris(dichloroisopropy)) phosphate (Comparative Example CE2) exhibits a substantial contribution of the flame retardant additive to fogging and achieves the best FMVSS fire class SE (self-extinguishing) in all repetitions of the fire test. However, tris(dichloroisopropyl) phosphate has the attendant disadvantages described above of a halogen-containing flame retardant. Although the use of the halogen-free flame retardant diphenyl cresyl phosphate (Comparative Example CE3) avoids this problem and also achieves a relatively low fogging value, the flame-retardant effect is inadequate, with FMVSS fire class BR. The flame retardants used in the Comparative Examples CE4 to CE6 have a very good flame-retardant effect (all self-extinguishing) and also give relatively low fogging values.

(18) Inventive Examples IE1 to IE3 show that the flexible polyurethane foams according to the invention likewise achieve the best fire class SE (self-extinguishing) in all repetitions of the fire test and feature the lowest fogging values. In particular, fogging is lower in IE1 to IE3 than in Comparative Example CE4, in which the flame retardant diethylene glycol bis(diethyl phosphate) (F3) was processed. F3 is structurally related to the oligomer mixtures according to the invention, corresponding to formula II where R.sup.1R.sup.2R.sup.3R.sup.4=ethyl and A=CH.sub.2CH.sub.2OCH.sub.2CH.sub.2 and n=1.00.

(19) TABLE-US-00005 TABLE 5 Composition (parts by weight) and test results for Inventive Examples IE4 to IE6 and for Non-inventive Comparative Examples CE7 to CE13 relating to flexible polyester foams Example CE7 CE8 CE9 CE10 CE11 CE12 CE13 IE4 IE5 IE6 A 100 100 100 100 100 100 100 100 100 100 B 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 C 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 D 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 E 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 F1 4 F2 4 F3 4 F4 4 F5 4 F6 4 F7 4 F8 4 F9 4 G 24.1 24.1 24.1 24.1 24.1 24.1 24.1 24.1 24.1 24.1 H 24.1 24.1 24.1 24.1 24.1 24.1 24.1 24.1 24.1 24.1 Foam structure uf uf uf uf nc nc nc uf uf uf FMVSS class RB SE BR SE SE SE SE
Evaluation of the Results Related to Flexible Polyester Foams

(20) In the absence of a flame retardant (Comparative Example CE7) the flexible polyurethane foam is rapidly consumed by combustion (FMVSS fire class RB). A foam with tris(dichloroisopropyl) phosphate (Comparative Example CE8) achieves the best FMVSS fire class SE (self-extinguishing) in all repetitions of the fire test. However, tris(dichloroisopropyl) phosphate has the attendant disadvantages described above of a halogen-containing flame retardant. Although the use of the halogen-free flame retardant diphenyl cresyl phosphate (Comparative Example CE9) avoids this problem, the flame-retardant effect is inadequate, with FMVSS fire class BR. The Comparative Example CE10 likewise achieves the best classification in the fire test. The flame retardants F4 (n=3.01), F5 (n=2.11) and F6 (n=2.44) (Comparative Examples CE11 to CE13) proved to be incompatible with the polyester polyols. These incompatibilities were apparent in a non-uniform, coarse-pored structure of the flexible polyester foams. Foams of this type cannot be used for the typical applications of flexible foam. For this reason, no FMVSS classes were determined for the Comparative Examples CE11 to CE13.

(21) Inventive Examples IE4 to IE6 show that the oligomer mixtures according to the invention can also be processed with polyester polyols without difficulty to give flexible polyurethane foams, and that these likewise achieve the best fire class SE (self-extinguishing) in all repetitions of the fire test.

(22) If the results from flexible polyether foams and flexible polyester foams are compared, it is apparent that the oligomer mixtures according to the invention can be used to produce not only flexible polyether foams but also flexible polyester foams, and that these also exhibit very good flame retardancy and low fogging values. None of the comparative products exhibits this combination of properties.