HEPTAPHOSPHORUS-DERIVED COMPOUNDS AS FLAME RETARDANTS

Abstract

The invention relates to flame retardant compositions comprising heptaphosphorus-derived compounds and to novel heptaphosphorus-derived compounds.

These heptaphosphorus-derived compounds are especially useful for the manufacture of flame retardant compositions based on thermoplastic polymers, especially polyolefin homo- and copolymers, polycondensates, such as polyamides, or polyesters and duro-plastic polymers, such as the ones based on polyepoxides.

Claims

1.-18. (canceled)

19. A composition, which comprises a) a heptaphosphorus-derived (P.sub.7) compound; and b) a polymer substrate.

20. The composition according to claim 19, wherein the heptaphosphorus-derived (P.sub.7) compound selected from the group consisting of zinc heptaphosphorus halide, triazine heptaphosphide, tris-trialkylsilyl-heptaphosphide and trialkylheptaphosphine.

21. The composition according to claim 19, which comprises a) a heptaphosphorus-derived (P.sub.7) compound selected from the group consisting of zinc heptaphosphorus chloride, melamine heptaphosphide, tris-trimethylsilyl-heptaphosphide and trialkylheptaphosphine of the formula
P.sub.7(R.sub.x).sub.3 (I), wherein R.sub.x represents a group of the partial formula
CR.sub.1R.sub.2R.sub.3 (A), wherein a) one of R.sub.1, R.sub.2 and R.sub.3 represents hydrogen; one of R.sub.1, R.sub.2 and R.sub.3 represents C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted by phenyl; and one of R.sub.1, R.sub.2 and R.sub.3 represents the group of the partial formula
CHCR.sub.aR.sub.b (B), wherein one of R.sub.a and R.sub.b represents (C.sub.1-C.sub.4alkyl).sub.3silyl; and the other one of R.sub.a and R.sub.b represents C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted by phenyl; or b) one of R.sub.1, R.sub.2 and R.sub.3 represents hydrogen; one of R.sub.1, R.sub.2 and R.sub.3 represents C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted by phenyl; and one of R.sub.1, R.sub.2 and R.sub.3 represents the group of the partial formula
CHC(O)R.sub.a (C), wherein R.sub.a represents C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted by phenyl; or wherein c) one of R.sub.1, R.sub.2 and R.sub.3 represents hydroxy; one of R.sub.1, R.sub.2 and R.sub.3 represents hydrogen; and one of R.sub.1, R.sub.2 and R.sub.3 represents C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted by phenyl; or d) one of R.sub.1, R.sub.2 and R.sub.3 represents hydroxy; and two of R.sub.1, R.sub.2 and R.sub.3 represent C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted by phenyl.

22. The composition according to claim 21, which comprises a) a heptaphosphorus-derived (P) compound selected from the group consisting of zinc heptaphosphorus chloride, melamine heptaphosphide, tris-trimethylsilyl-heptaphosphide and trialkylheptaphosphine (I), wherein R.sub.x represents the group (A), wherein a) one of R.sub.1, R.sub.2 and R.sub.3 represents hydrogen; one of R.sub.1, R.sub.2 and R.sub.3 represents C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted by phenyl; and one of R.sub.1, R.sub.2 and R.sub.3 represents the group (B), wherein one of R.sub.a and R.sub.b represents (C.sub.1-C.sub.4alkyl).sub.3silyl; and the other one of R.sub.a and R.sub.b represents C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted by phenyl; or b) one of R.sub.1, R.sub.2 and R.sub.3 represents hydrogen; one of R.sub.1, R.sub.2 and R.sub.3 represents C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted by phenyl; and one of R.sub.1, R.sub.2 and R.sub.3 represents the group (C), wherein R.sub.a represents C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted by phenyl.

23. The composition according to claim 22, which comprises a) a heptaphosphorus-derived (P.sub.7) compound selected from the group consisting of zinc heptaphosphorus chloride, melamine heptaphosphide, tris-trimethylsilyl-heptaphosphide and trialkylheptaphosphine (I), wherein R.sub.x represents the group (A), wherein a) one of R.sub.1, R.sub.2 and R.sub.3 represents hydrogen; one of R.sub.1, R.sub.2 and R.sub.3 represents phenyl; and one of R.sub.1, R.sub.2 and R.sub.3 represents the group (B), wherein one of R.sub.a and R.sub.b represents trimethylsilyl; and the other one of R.sub.a and R.sub.b represents phenyl; or b) one of R.sub.1, R.sub.2 and R.sub.3 represents hydrogen; one of R.sub.1, R.sub.2 and R.sub.3 represents phenyl; and one of R.sub.1, R.sub.2 and R.sub.3 represents the group (C), wherein R.sub.a represents phenyl.

24. The composition according to claim 19, which comprises a) a heptaphosphorus-derived (P.sub.7) compound; and b) a thermoplastic polymer substrate.

25. The composition according to claim 24, which comprises a) a heptaphosphorus-derived (P.sub.7) compound; and b) a polyfunctional epoxide compound, and, optionally, a hardener compound.

26. The composition according to claim 19, which comprises as an optional component additional flame retardants and additives selected from the group consisting of tetraalkylpiperidine additives, polymer stabilizers, fillers, reinforcing agents and so-called anti-dripping agents that reduce the melt flow of thermoplastic polymers and reduce the formation of drops at higher temperatures.

27. The composition according to claim 26, which comprises as an optional component at least one additional flame retardant selected from the group consisting of phosphorus flame retardants, nitrogen generating flame retardants, organohalogen containing flame retardants and inorganic flame retardants.

28. The composition according to claim 27, which comprises as an additional flame retardant a nitrogen containing compound selected from the group consisting of melamine cyanurate, melamine phosphate, melamine polyphosphate, ammonium polyphosphate, melamine ammonium phosphate, melamine ammonium polyphosphate, melamine ammonium pyrophosphate, a condensation product of melamine with phosphoric acid and other reaction products of melamine with phosphoric acid and mixtures thereof.

29. The composition according to claim 28, which comprises as an additional flame retardant a phosphorus containing flame retardant selected from the group consisting of tetra(2,6-dimethylphenyl)resorcinol diphosphate, salts of di-C.sub.1-C.sub.4alkylphosphinic acid, salts of hypophosphoric acid and 9,10-dihydro-9-oxa-10-phosphorylphenanthrene-10-oxide (DOPO) and its derivatives.

30. The composition according to claim 26, which additionally comprises at least one tetraalkylpiperidine derivative selected from the group consisting of 1-Cyclohexyloxy-2,2,6,6-tetramethyl-4-octadecylaminopiperidine, bis(1-Octyloxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate, 2,4-bis [(1-Cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)butylamino]-6-(2-hydroxyethyl-amino-s-triazine, bis(1-Cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl) adipate, 2,4-bis[(1-Cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)butylamino]-6-chloro-s-triazine, 1-(2-Hydroxy-2-methylpropoxy)-4-hydroxy-2,2,6,6-tetramethylpiperidine, 1-(2-Hydroxy-2-methylpropoxy)-4-oxo-2,2,6,6-tetramethylpiperidine, 1-(2-Hydroxy-2-methylpropoxy)-4-octadecanoyloxy-2,2,6,6-tetramethylpiperidine, bis(1-(2-Hydroxy-2-methylpropoxy)-2,2,6,6-tetramethylpiperidin-4-yl) sebacate, bis(1-(2-Hydroxy-2-methylpropoxy)-2,2,6,6-tetramethylpiperidin-4-yl) adipate, 2,4-bis{N-[1-(2-Hydroxy-2-methylpropoxy)-2,2,6,6-tetramethylpiperidin-4-yl]-N-butylaminol}-6-(2-hydroxyethylamino)-s-triazine, the reaction product of 2,4-bis[(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)-butylamino]-6-chloro-s-triazine with N,N-bis(3-aminopropyl)ethylenediamine), 2,4-bis[(1-Cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)butyl amino]-6-(2-hydroxyethyl-amino)-s-triazine, the oligomeric compound which is the condensation product of 4,4-hexamethylenebis(amino-2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-6-[(1-cyclohexyloxy-2,2,6,6-tetramethyl-piperidin-4-yl)butylamino]-s-triazine end-capped with 2-chloro-4,6-bis(dibutylamino)-s-triazine, the compound of the formula ##STR00008## and the compound of the formula ##STR00009## in which n is from 1 to 15

31. A process for inducing flame retardancy in polymers, which comprises adding to a polymer substrate a heptaphosphorus-derived (P.sub.7) compound.

32. A heptaphosphorus-derived (P.sub.7) compound selected from the group consisting of triazine heptaphosphide and trialkylheptaphosphine of the formula
P.sub.7(R.sub.x).sub.3 (I) wherein R.sub.x represents a group of the partial formula
CR.sub.1R.sub.2R.sub.3 (A), wherein a) one of R.sub.1, R.sub.2 and R.sub.3 represents hydrogen; one of R.sub.1, R.sub.2 and R.sub.3 represents C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted by phenyl; and one of R.sub.1, R.sub.2 and R.sub.3 represents the group of the partial formula
CHCR.sub.aR.sub.b (B), wherein one of R.sub.a and R.sub.b represents (C.sub.1-C.sub.4alkyl).sub.3silyl; and the other one of R.sub.a and R.sub.b represents C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted by phenyl; or b) one of R.sub.1, R.sub.2 and R.sub.3 represents hydrogen; one of R.sub.1, R.sub.2 and R.sub.3 represents C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted by phenyl; and one of R.sub.1, R.sub.2 and R.sub.3 represents the group of the partial formula
CHC(O)R.sub.a (C), wherein R.sub.a represents C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted by phenyl; or wherein c) one of R.sub.1, R.sub.2 and R.sub.3 represents hydroxy; one of R.sub.1, R.sub.2 and R.sub.3 represents hydrogen; and one of R.sub.1, R.sub.2 and R.sub.3 represents C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted by phenyl; or d) one of R.sub.1, R.sub.2 and R.sub.3 represents hydroxy; and two of R.sub.1, R.sub.2 and R.sub.3 represent C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted by phenyl.

33. The heptaphosphorus-derived (P.sub.7) compound according to claim 32 selected from the group consisting of melamine heptaphosphide and trialkylheptaphosphine (I), wherein R.sub.x represents the group (A), wherein a) one of R.sub.1, R.sub.2 and R.sub.3 represents hydrogen; one of R.sub.1, R.sub.2 and R.sub.3 represents C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted by phenyl; and one of R.sub.1, R.sub.2 and R.sub.3 represents the group (B), wherein one of Ra and Rb represents (C1-C4alkyl)3silyl; and the other one of Ra and Rb represents C1-C4-alkyl, phenyl or C1-C4-alkyl substituted by phenyl; or b) one of R.sub.1, R.sub.2 and R.sub.3 represents hydrogen; one of R.sub.1, R.sub.2 and R.sub.3 represents C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted by phenyl; and one of R.sub.1, R.sub.2 and R.sub.3 represents the group (C), wherein R.sub.a represents C.sub.1-C.sub.4-alkyl, phenyl or C.sub.1-C.sub.4-alkyl substituted bisy phenyl.

34. The heptaphosphorus-derived (P.sub.7) compound according to claim 32 wherein the heptaphosphorus-derived (P.sub.7) compound is trimelamine heptaphosphide.

35. The heptaphosphorus-derived (P.sub.7) compound according to claim 32 , wherein the compound is a trialkylheptaphosphine compound (I) and R.sub.x represents the group (A), wherein a) one of R.sub.1, R.sub.2 and R.sub.3 represents hydrogen; one of R.sub.1, R.sub.2 and R.sub.3 represents phenyl; and one of R.sub.1, R.sub.2 and R.sub.3 represents the group (B), wherein one of R.sub.a and R.sub.b represents trimethylsilyl; and the other one of R.sub.a and R.sub.b represents phenyl; or b) one of R.sub.1, R.sub.2 and R.sub.3 represents hydrogen; one of R.sub.1, R.sub.2 and R.sub.3 represents phenyl; and one of R.sub.1, R.sub.2 and R.sub.3 represents the group (C), wherein R.sub.a represents phenyl.

36. A process for inducing flame retardancy in polymers which comprises utilizing the heptaphosphorus-derived (P.sub.7) compound according to claim 32.

Description

EXAMPLES

[0228] Abbreviations

[0229] sec: second(s)

[0230] min: minute(s)

[0231] h: hours(s)

[0232] rpm: rotations per minute

[0233] IEC: International Electrotechnical Commission

[0234] ISO: International Organization for Standardization

[0235] TMS: Trimethylsilyl group

[0236] THF: Tetrahydrofuran

[0237] P.sub.7(TMS).sub.3: tris-(Trimethylsilyl)-heptaphosphine

[0238] P.sub.7(TMS-chalcone).sub.3: tris[1,3-diphenyl-3-(trimethylsilyloxy)-2-propenyl)]heptaphosphine

[0239] P.sub.7(chalcone).sub.3: tris-1(1,3-diphenyl-3-oxopropyl)heptaphosphine

Example 1

a) Preparation of tris(1,3-diphenyl-3-trimethylsilyloxy-2-propenyl)heptaphosphine from chalcone and P.SUB.7.TMS.SUB.3

[0240] Dissolve 0.100 g (0.229 mmol) P.sub.7(TMS).sub.3 (as obtained by the method described in H. Schmidbaur, A. Bauer, An improved preparation of tris(trimethylsilyl)heptaphosphine, Phosphorus, Sulfur, and Silicon, 1995, Vol. 102. pp. 217-219) in 3 ml THF and add drop-wise a THF solution of 0.143 g (0.687 mmol) 1,3-diphenyl-2-propen-1-one, [(E)-chalcone], Sigma Aldrich Co. LLC). Remove the THF under reduced pressure. Wash the residue with hexane and dry the light yellow powder under reduced pressure. Crystals suitable for single crystal x-ray diffraction are grown from a slowly evaporating THF solution of the title product (P.sub.7(TMS-chalcone).sub.3). The product is obtained with a purity exceeding 95%.

[0241] Analytical Data

[0242] Elemental analysis [% found/% theory]: C: 61.52/61.20; H: 6,35/5.98; P: 19.88/20.43;

[0243] .sup.1H NMR (THF-d8): 7.53-7.01 (m, 30H), 5.89-5.59 (m, 3H), 4.79-4.49 (m, 3H), 0.10 (s, 27H);

[0244] .sup.31P NMR (THF-d8): 122.48-100.84 (m, 3P), 112.49-130.50 (m, 1P), 156.12-177.15 (m, 3P);

[0245] Raman [cm.sup.1]: 3057, 2956, 2897, 1634, 1596, 1487, 1445, 1404, 1342, 1310, 1277, 1212, 1186, 1154, 1094, 1021, 997, 903, 826, 764, 720, 685, 638, 605, 520, 472, 408, 387, 367, 346, 293, 272;

[0246] TGA Nitrogen: T5% mass loss: 221 C., T50% mass loss: 272 C.

b) Evaluation of P.SUB.7.(TMS-chalcone).SUB.3 .as a Flame Retardant in polyurethane

[0247] The adduct P.sub.7(TMS-chalcone).sub.3 is incorporated with the amounts indicated in Table 1 into thermoplastic polyurethane by melt extrusion with a double screw extruder that operates at 80 rpm and a temperature of 210 C. The residence time of the product is 3 min. Test bars with dimensions of 125 mm13 mm1.6 mm are prepared by injection molding with a pressure of 10 bar. Specimen are tested in the vertical flame test according to IEC 60695-11-20, with the limitation that only two test bars are used to obtain the after flame time. Samples of P.sub.7(TMS-chalcone).sub.3 extinguish readily, as shown in Table 1.

TABLE-US-00001 TABLE 1 Polyurethane formulations and results of vertical flame test. Amounts [% w/w] 1 2 Elastollan (BASF Polyurethanes GmbH) 1185 100.0 96.4 A10 tris(1,3-Diphenyl-3-trimethylsilyloxy-2-propenyl)- 0.0 3.6 heptaphosphine [=P.sub.7(TMS-Chalcone).sub.3] Classification IEC60695-11-20 V-2 V-0 After-flame time t1 [s] 1 2 After-flame time t2 [s] 1 1 Cotton pad ignited Yes No

Example 2

a) Preparation of tris-1(1,3-diphenyl-3-oxopropyl)heptaphosphine by Removal of silyl Group in P.SUB.7.TMS-chalcone.SUB.3

[0248] In a 50 ml Schlenk flask, 0.250 g P.sub.7(TMS-chalcone).sub.3 are combined with 0.250 g NH.sub.4F (Sigma Aldrich Co. LLC). 15 ml acetonitrile are added under a flow of inert gas and stirred overnight. The acetonitrile is removed, and the residue taken into THF and filtered. THF is removed under reduced pressure and the residue mobilized with hexane. The light yellow powder P.sub.7(chalcone).sub.3 is filtered and dried under reduced pressure.

[0249] Analytical Data

[0250] Elemental analysis [% found/% theory]: C: 63.74/63.99; H: 4.89/4.65; P: 25.69/25.67;

[0251] .sup.31P NMR (THF-d.sub.8): 139.48-105.12 (br.), 100.68-60.12 (br.), 60.53-33.04 (br.), 31.05-32.66 (br.);

[0252] MS (MALDI+): Predicted m/z=845.1135. Measured m/z=845.1134;

[0253] TGA Nitrogen: T5% mass loss: 204 C., T50% mass loss: 308 C.

b) Evaluation of tris-1-(1,3-diphenyl-3-oxopropyl)heptaphosphine as a Flame Retardant in Thermoset epoxy

[0254] Isophoronediamine (3-aminomethyl-3,5,5-trimethylcyclohexylamine, BASF SE), a medium viscosity bisphenol-A epoxy resin (Epilox (LEUNA-Harze GmbH) A 19-03) and P.sub.7(chalcone).sub.3 are combined at room temperature in a 50 ml beaker with the amounts indicated in Table 2 and immediately mixed with a high-speed mixing system (Hauschild DAC 600) at 2000 rpm for 4 min. No temperature increase is observed during mixing. The mixtures are poured into a round aluminium dish with an inner diameter of 85 mm. The mixture is cured for 2 h at 80 C. and 3 h at 125 C. under reduced pressure (100 mbar). The procedure yields fully cured epoxy discs with a diameter of 85 mm and a thickness of approximately 4 mm.

TABLE-US-00002 TABLE 2 Epoxy formulations Components Formulation 1 [g] Formulation 2 [g] Isophoronediamine 4.67 4.67 Epilox (LEUNA-Harze 20.33 20.33 GmbH) A 19-03 P.sub.7Chalcone.sub.3 0 4.06

[0255] The flammability properties of the epoxy formulations according to Table 2 are tested with a cone calorimeter following the procedures of ISO-5660-1, with the exception of using a round-shaped specimen instead of a square specimen. The results are summarized in Table 3 and show that the heat release rate of the epoxy is strongly reduced by P.sub.7chalcone.sub.3.

TABLE-US-00003 TABLE 3 Flammability properties according to ISO 5660-1 Sample 1 2 Peak Heat Release Rate 1940 655 [kW m.sup.2] Maximum Average Rate of 686 227 Heat Emission [kW m.sup.2] Total Heat Release [MJ m.sup.2] 106 79 Residual mass [%] 1.7 9.5

c) Preparation of Transparent epoxy Plates with tris-1-(1,3-diphenyl-3-oxopropyl)heptaphosphine

[0256] 2.3 g tris-1-(1,3-Diphenyl-3-oxopropyl)heptaphosphine are given to dimethylformamide (DMF, Sigma Aldrich Co. LLC) to prepare a 5% w/w solution of the heptaphosphine compound in DMF. 23.0 g of a medium viscosity bisphenol-A epoxy resin (Epilox (LEUNA-Harze GmbH) A 19-03) are added and the solution is homogenized on a shaking table for 1 h. A clear solution is obtained. DMF is removed by storage under reduced pressure of 5 kPa for 16 h at a temperature of 100 C. The solution of tris-1-(1,3-diphenyl-3-oxopropyl)heptaphosphine in the epoxy resin remains fully transparent after removing DMF and cooling the solution to room temperature.

[0257] 3.0 g Triethylenetetramine (CAS No, 112-24-3, Sigma Aldrich Co. LLC) are added to 23.0 g of the solution of tris-1-(1,3-diphenyl-3-oxopropyl)heptaphosphine bisphenol-A epoxy resin and intensively mixed with a high-speed mixing system (Hauschild DAC 600) at 2000 rpm for 2 min. 22.0 g of the obtained mixture are poured into a flat aluminium dish with an inner diameter of 84 mm. The mixture is cured for 4 h at room temperature under atmospheric pressure and then cured for a further 2 h at a temperature of 120 C. under atmospheric pressure. A flat disc with a diameter of 84 mm is thus obtained. The sample is polished to a thickness of 3.1 mm in order to remove small bubbles from the surface. A digital photograph of the sample (FIG. 1) shows that a fully transparent material is obtained.

[0258] The flammability properties of the transparent epoxy plate containing 8.0% w/w of tris-1-(1,3-diphenyl-3-oxopropyl)heptaphosphine are tested with a cone calorimeter following the procedures of ISO-5660-1, with the exception of using a round-shaped specimen instead of a square specimen. The results are summarized in Table 4 and show that the heat release rate of the epoxy is strongly reduced by of tris-1-(1,3-diphenyl-3-oxopropyl)heptaphosphine.

TABLE-US-00004 TABLE 4 Flammability properties according to ISO 5660-1 Sample 1 Peak Heat Release Rate 720 [kW m.sup.2] Maximum Average Rate of 388 Heat Emission [kW m.sup.2] Total Heat Release [MJ m.sup.2] 64

Example 3

a) Preparation of the Decomposition Product of P.SUB.7.(TMS).SUB.3 .in the Presence of melamine (P.SUB.7.melamine Compound)

[0259] By choice of the molar ratios of the starting materials P.sub.7(TMS).sub.3 and melamine, coordination polymers with different molar ratios of melamine can be obtained. In this example, the amount of the starting materials is chosen such that a ratio of melamine to P.sub.7 of 1:1 is obtained in the final product. It is confirmed by observation of the characteristic vibrations in Raman spectroscopy that the P.sub.7 cage remains intact in the final product.

[0260] A slurry of 0.100 g (0.802 mmol) melamine (Sigma Aldrich Co. LLC) in 4 ml methanol (124 mmol) is stirred, and 0.350 g (0.802 mmol) P.sub.7(TMS).sub.3 dissolved in 3 ml toluene is added drop-wise. A yellow precipitate is formed within 30 min. The reaction mixture is stirred over night at 70 C. The mixture is filtered and the solid obtained is washed 2 times with 2 ml THF and dried for one hour under reduced pressure at 100 C.

[0261] Analytical Data

[0262] Elemental analysis [% found/% theory]: C: 12.5/10.4: N: 23.1/24.3; P: 57/62.7; Other: 7.4; Estimation for theoretical values: ratio of melamine to P.sub.7 equals 1:1.

[0263] Raman [cm.sup.1]: 2242, 865, 738, 700, 656, 602, 505, 440, 405, 381, 351, 281;

[0264] TGA Nitrogen: T5% mass loss: 232 C., T50% mass loss: 417 C.

b) Evaluation of P.SUB.7 .melamine Compound as a Flame Retardant in Rigid polyurethane Foam

[0265] The P.sub.7melamine compound is added to a polyether polyol with a viscosity of 2 Pa s (DIN 51 550) and OH-number of 400 mg KOH/g (DIN 53 240). A dispersion of the salt is obtained by stirring with a Lenart disc (Paul Vollrath GmbH & Co KG) at 1200 rpm for 2 min. Water, silicone surfactant, catalyst and blowing agent are added to the polyol blend and are homogenized by further stirring with the Lenart disc for 1 min at 1200 rpm. The isocyanate is added, and the mixture is immediately stirred with 1200 rpm for 10 sec. The reaction mixture is poured into a cardboard cup. The mixture expands immediately to form a cellular body with a multiple of the initial pour height. The same procedure is used to obtain a comparative example without a flame retardant (control). Concentrations indicated in Table 5 result in foam bodies with low densities of about 50 g l.sup.1 and a predominantly closed cell structure.

TABLE-US-00005 TABLE 5 Polyurethane rigid foam formulation Amount Components [g/100 g Polyol] Polyether polyol (Lupranol 3424, BASF 100.00 Polyurethanes GmbH) Surfactant Tegostab 8467 (Evonik Industries AG) 2.40 8467 Catalyst N,N-dimethylcyclohexylamine (Lupragen 5.00 N100, BASF SE) Blowing agent cyclopentane (Cyclopentane PU 95%, 15.00 TCI Europe N.V.) Deionized water 0.85 Polymeric methylene diphenyl isocyanate (Lupranat 106.26 M20 S, BASF Polyurethanes GmbH) P.sub.7Melamine compound 5.00

[0266] The flammability of the samples is tested in the vertical flame test according to Underwriters Laboratory standard 94 with the modification of the foam body being a round disc of 85 mm outer diameter and thickness of 20 mm. Flames are applied to the lower edge of the specimen. The results of the tests are reported in Table 6. The residual mass and the physical appearance of the residual samples after the burn test are also reported in Table 6. Addition of the P.sub.7melamine compound results in extinction of the flame, and the foam core remains intact.

TABLE-US-00006 TABLE 6 Flammability properties of rigid polyurethane foams Samples 1 2 Flame retardant None P.sub.7Melamine salt Amounts [g/100 g polyol] 5 After burn time 1 [sec] 60 28 After burn time 2 [sec] 4 Classification UL94 none V-1 Residual mass [%] 22 83 Physical appearance Hollow shell Foam with burned surface layer

Example4

a) Preparation of the Decomposition Products, of P.SUB.7.(TMS).SUB.3 .in the Presence of ZnCl.SUB.2

[0267] A solution of 0.19 g zinc dichloride (Sigma Aldrich Co. LLC) in THF is stirred and 0.2 g (0.458 mmol) P.sub.7(TMS).sub.3 dissolved in 3 ml THF is added drop-wise. A yellow precipitate is formed immediately. The reaction mixture is stirred overnight at room temperature. The solid is filtered, washed with 2 ml THF and dried under reduced pressure.

[0268] Analytical Data

[0269] Elemental analysis [% found]: P 24.6; Si: 0.04; Zn: 26.6; Other: 48.8;

[0270] TGA Nitrogen: T5% mass loss: 405 C., T50% mass loss: 600 C.

b) Evaluation of the Decomposition Products of P.SUB.7.(TMS).SUB.3 .in the Presence of ZnCl.SUB.2 .as a Flame Retardant in Thermoplastic Polybutylene Terephthalate (PBT)

[0271] The zinc chloride heptaphosphide salt is incorporated in the amounts indicated in Table 7 into PBT by melt extrusion on a double screw extruder that operates at 80 rpm at a temperature of 260 C. The residence time of the product is 3 min. Test bars with dimensions of 125 mm13 mm1.6 mm are prepared by injection molding with a pressure of 10 bar. Specimen are tested in the vertical flame test according to IEC 60695-11-20, with the limitation that only two test bars are used to obtain the after-flame times. Samples containing the zinc chloride heptaphosphide compound extinguish readily, as shown in Table 7.

TABLE-US-00007 TABLE 7 Vertical flame test result of zinc chloride heptaphosphide salt. Samples Components 1 2 Ultradur 4500 (BASF SE) [% w/w] 100.0 96.0 Zinc chloride heptaphosphide salt 0.0 4.0 Classification IEC60695-11-20 V-2 After-flame time t1 30 4 After-flame time t2 12 Cotton pad ignited Yes Yes

Example 5

a) Preparation of tris(1-phenyl-3-trimethylsiloxy-2-propenyl)heptaphosohide from cinnamaldehyde and P.SUB.7.(TMS).SUB.3

[0272] P.sub.7(TMS).sub.3 (4.00 g, 9.166 mmol) is dissolved in 20 ml THF in a Schlenk flask and cinnamaldehyde (3.63 g, 27.499 mmol) slowly added to the stirred solution. The solution is slightly warming up. The reaction mixture is stirred overnight and THF removed under reduced pressure to give tris(1-phenyl-3-trimethylsiloxy-2-propenyl)heptaphosphine. The product is obtained with a purity of 95%.

[0273] Analytical Data

[0274] .sup.31P NMR (THF-d8): 129.97-106.51 (m, 3P), 99.20-130.50 (m, 1P), 149.28-178.25 (m, 3P);

[0275] Elemental analysis [% found/theory]: C: 51.31/51.54; H:6.27/6.85; P: 25.95/25.85.

b) Preparation of tris(3-oxo-1-phenyl-propyl)heptaphosphine by Removal of silyl Group from tris(1-phenyl -3-trimethylsiloxy-2-propenyl)heptaphosphine

[0276] 20 ml acetonitrile is added to tris(1-phenyl-3-trimethylsiloxy-2-propenyl)heptaphosphine prepared as decribed above, followed by 3.058 g (103.12 mmol) of NH.sub.4F (Sigma Aldrich Co. LLC). The reaction mixture is stirred overnight and the acetonitrile then decanted. 40 ml THF is added and the solution is washed with 220 ml degassed water to remove the NH.sub.4F. The bright yellow solid is filtered on a glass frit and washed with 310 ml THF, followed by 310 ml diethyl ether. Volatiles are removed under reduced pressure overnight to yield a bright yellow powder. The desired product tris(3-oxo-1-phenyl-propyl)heptaphosphine is obtained with a purity of about 92%.

[0277] The obtained compound is easily subject to oligomerization and/or condensation reactions which makes purification for elemental analysis difficult. The desired structure is confirmed by MALDI-MS measurements.

[0278] Analytic Data

[0279] Elemental analysis [% found/theory]: C: 49.0/52.6; H:4.9/4.4; O: 8.0/7.8; P: 34.0/35.2;

[0280] TGA Nitrogen: T5% mass loss: 214 C., T50% mass loss: 352 C.;

[0281] MS (MALDI+): Predicted m/z=617.0196. Measured m/z=617,0198.

c) Evaluation of tris(3-oxo-1-phonyl-propyl)heptaphosphine as a Flame Retardent in Thermoset Epoxy

[0282] Isophoronediamine, a medium viscosity bisphenol A epoxy resin (Epilox (LEUNA-Harze GmbH) A 19-03) and tris-(3-oxo-1-phenyl-propyl)heptaphosphine are combined at room temperature in a 50 ml beaker in the amounts given in Table 8 and immediately mixed with a high-speed mixing system (Hauschild DAC 600) at 2000 rpm for 4 min. No temperature increase is observed during mixing. The mixtures are poured into a round aluminium dish with an inner diameter of 85 mm. The mixture is cured for 2 h at 80 C. and 3 h at 125 C. under reduced pressure (100 mbar). The procedure gives fully cured epoxy discs with a diameter of 85 mm and a thickness of approximately 4 mm.

TABLE-US-00008 TABLE 8 Epoxy formulations Components Formulation 1 [g] Formulation 2 [g] Isophoronediamine 4.67 4.67 Epilox (LEUNA-Harze 20.33 20.33 GmbH) A 19-03 Tris(3-oxo-1-phenylpropyl) 0 2.03 heptaphosphine

[0283] The flammability properties of the epoxy formulations according to Table 8 are tested with a cone calorimeter following the procedures of ISO-5660-1, with the variation of using a round specimen instead of a square disc. The results are summarized in Table 9 and show that the heat release rate of the epoxy is strongly reduced by tris(3-oxo-1-phenyl-propyl)heptaphosphine.

TABLE-US-00009 TABLE 9 Flammability properties according to ISO 5660-1 1 2 Peak heat release rate 1940 1009 [kW m.sup.2] Maximum average rate of 686 398 heat emission [kW m.sup.2] Total heat release [MJ m.sup.2] 106 81 Residual mass [%] 1.7 8.2

d) Preparation of Transparent Expoxy Plates with tris(3-oxo-1-phenyl-propyl)heptaphosphine

[0284] 2.3 g of tris(3-oxo-1-phenyl-propyl)heptaphosphine are given to dimethylformamide (DMF, Sigma Aldrich Co. LLC) to prepare a 5% w/w solution of the heptaphosphine compound in DMF. 23.0 g of a medium viscosity bisphenol-A epoxy resin (Epilox (LEUNA-Harze GmbH) A 19-03) are added, and the solution is homogenized on a shaking table for 1 h. A clear solution is obtained. DMF is removed by storage under reduced pressure of 5 kPa for 16 h at a temperature of 100 C. The solution of tris-1-(1,3-diphenyl-3-oxopropyl)heptaphosphine in the epoxy resin remains fully transparent after removing DMF and cooling the solution to room temperature.

[0285] 3.0 g Triethylenetetramine (CAS No. 112-24-3, Sigma Aldrich Co. LLC) are added to 23.0 g of the solution of tris(3-oxo-1-phenyl-propyl)heptaphosphine in the bisphenol-A epoxy resin and intensively mixed with a high-speed mixing system (Hauschild DAC 600) at 2000 rpm for 2 min. 22.0 g of the obtained mixture are poored into a flat aluminium dish with an inner diameter of 84 mm. The mixture is cured for 4 h at room temperature under atmospheric pressure and then cured for a further 2 h at a temperature of 120 C. under atmospheric pressure. A flat disc with a diameter of 84 mm is obtained. The sample is polished to a thickness of 3.3 mm in order to remove small bubbles from the surface. A digital photograph of the sample (FIG. 2) shows that a fully transparent material is obtained.

[0286] The flammability properties of the transparent epoxy plate containing 8.0% w/w tris(3-oxo-1-phenyl-propyl)heptaphosphine_are tested with a cone calorimeter following the procedures of ISO-5660-1, with the exception of using a round-shaped specimen instead of a square specimen. The results are summarized in Table 10 and show that the heat release rate of the epoxy is strongly reduced by tris(3-oxo-1-phenyl-propyl)heptaphosphine.

[0287] The comparison according to Example 5e) (see below) demonstrates that the flame retardant effect of tris(3-oxo-1-phenyl-propyl)heptaphosphine is comparable to the effect of red phosphorus when the same elemental concentration of phosphorus is used.

TABLE-US-00010 TABLE 10 Flammability properties according to ISO 5660-1 Sample 1 Peak Heat Release Rate 808 [kW m.sup.2] Maximum Average Rate of 388 Heat Emission [kW m.sup.2] Total Heat Release [MJ m.sup.2] 59

Comparative Example

e) Preparation of Epoxy Plates with Red Phosphorus

[0288] 1.73 g red phosphorus paste (Exolit RP 6520 available from Clariant SE) with an elemental concentration of phosphorus of 45% w/w are combined with 23.0 g medium viscosity bisphenol-A epoxy resin (Epilox (LEUNA-Harze GmbH) A 19-03) and 3.0 g triethylenetetramine (CAS No.112-24-3, Sigma Aldrich Co. LLC). The mixture is intensively mixed with a high-speed mixing system (Hauschild DAC 600) at 2000 rpm for 2 min. 22.0 g of the obtained mixture are poured into a flat aluminium dish with an inner diameter of 84 mm. The mixture is cured for 4 h at room temperature under atmospheric pressure and then cured for a further 2 h at a temperature of 120 C. under atmospheric pressure. A flat disc with a diameter of 84 mm is obtained. The sample is polished to a thickness of 3.4 mm in order to remove small bubbles from the surface. The material has an elemental concentration of phosphorus of 2.8% (w/w), which corresponds to the elemental concentration of phosphorus of the material described above (Example 5d)). A digital photograph of the sample is shown in FIG. 3.

[0289] The flammability properties of the epoxy plate containing red phosphorus are tested with a cone calorimeter following the procedures of IS0-5660-1, with the exception of using a round-shaped specimen instead of a square specimen. The results are summarized in Table 11.

TABLE-US-00011 TABLE 11 Flammability properties according to ISO 5660-1 Sample 1 Peak Heat Release Rate 868 [kW m.sup.2] Maximum Average Rate of 353 Heat Emission [kW m.sup.2] Total Heat Release [MJ m.sup.2] 53.4