FLAME PROTECTION AGENT MIXTURES, THEIR PREPARATION AND THEIR USE

Abstract

Flame retardant mixtures and the production and use thereof

The invention relates to a flame retardant mixture comprising 99.9999% to 87% by weight of diorganylphosphinic salts as component A) and 0.0001% to 13% by weight of iron as component B), where the sum total of A) and B) is 100% by weight; and to processes for preparation thereof and to the use thereof.

Claims

1. A flame retardant mixture comprising: 99.9999% to 87% by weight of diorganylphosphinic salts as component A); and 0.0001% to 13% by weight of iron as component B), where the sum total of A) and B) is 100% by weight.

2. The flame retardant mixture as claimed in claim 1, comprising: 99.9999% to 75% by weight of diorganylphosphinic salts as component A); and 0.0001% to 13% by weight of iron in the form of an iron-containing substance B1) as component B), where the amount of B1) is 0.0001% to 25% by weight, and where the sum total of A0 and B1) is 100% by weight.

3. The flame retardant mixture as claimed in claim 1, wherein the diorganylphosphinic acid salts conform to the formula (II) ##STR00003## in which R.sup.1 and R.sup.2 are the same or different and are C.sub.1-C.sub.18-alkyl in linear, branched or cyclic form, C.sub.6-C.sub.18-aryl, C.sub.7-C.sub.18-arylalkyl and/or C.sub.7-C.sub.18-alkylaryl, m is 1 to 4, and M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zr, Zn, Ce, Bi, Sr, Mn, Li, Na and/or K.

4. The flame retardant mixture as claimed in claim 1, wherein R.sup.1, R.sup.2 in formula (II) are the same or different and are independently methyl, ethyl, n-propyl, isopropyl, butyl, n-butyl, tert-butyl, n-pentyl, 2-pentyl, 3-pentyl, 2-methylbutyl, 3-methylbutyl (isopentyl), 3-methylbut-2-yl, 2-methylbut-2-yl, 2,2-dimethylpropyl (neopentyl), hexyl, heptyl, octyl, nonyl, decyl, cyclopentyl, cyclopentylethyl, cyclohexyl, cyclohexylethyl, phenyl, phenylethyl, methylphenyl and/or methylphenylethyl.

5. The flame retardant mixture as claimed in claim 1, which comprises 99.999% to 98% by weight of component A) and 0.001% to 2% by weight of component B).

6. The flame retardant mixture as claimed in claim 2, wherein component B1) comprises iron(II) dialkylphosphinates, iron(III) dialkylphosphinates, iron(II) monoalkylphosphinates, iron(III) monoalkylphosphinates, iron(II) alkylphosphonates, iron(III) alkylphosphonates, iron(II) phosphite, iron(III) phosphite, iron(II) phosphate, iron(III) phosphate.

7. The flame retardant mixture as claimed in claim 2, wherein component B1) comprises iron(II) bis- and/or iron(III) tris(diethylphosphinate), -(dipropylphosphinate), -(butylethylphosphinate), -(n-butylethylphosphinate), -(sec-butylethylphosphinate), -(hexylethylphosphinate), -(dibutylphosphinate), -(hexylbutylphosphinate), -(octylethylphosphinate), -(ethyl(cyclopentylethyl)phosphinate), -(butyl(cyclopentylethyl)phosphinate), -(ethyl(cyclohexylethyl)phosphinate), -(butyl(cyclohexylethyl)phosphinate), -(ethyl(phenylethyl)phosphinate), -(butyl(phenylethyl)phosphinate), -(ethyl(4-methylphenylethyl)phosphinate), -(butyl(4-methylphenylethyl)phosphinate), -(butylcyclopentylphosphinate), -(butylcyclohexylethylphosphinate), -(butylphenylphosphinate), -(ethyl(4-methylphenyl)phosphinate) and/or -(butyl(4-methylphenyl)phosphinate; or of iron(II)mono- and/or iron(III)mono(ethylphosphinate), -(propylphosphinate), -(butylphosphinate), -n-butylphosphinate, -(sec-butylphosphinate), -(hexylphosphinate) and/or -(octylphosphinate); or iron(II) and/or iron(III) ethylphosphonate, propylphosphonate, butylphosphonate, n-butylphosphonate, sec-butylphosphonate, hexylphosphonate and/or octylphosphonate.

8. The flame retardant mixture as claimed in claim 2, wherein components A) and B1) have been coprecipitated together.

9. The flame retardant mixture as claimed in claim 2, which comprises: 60% to 99.8999% by weight of component A), 0.0001% to 20% by weight of component B1) and 0.1% to 40% by weight of a further component C), where the sum total of components A), B1) and C) is 100% by weight, with the proviso that components A), B1) and C) are each different compounds.

10. The flame retardant mixture as claimed in claim 9, wherein components A), B1) and C) have been coprecipitated together.

11. The flame retardant mixture as claimed in claim 9, wherein components A) and C) are in the form of a homogeneous ionic compound and component B1) has been coprecipitated.

12. The flame retardant mixture as claimed in claim 9, wherein components A) and B1) have been coprecipitated together and component C) has been mixed in by physical means.

13. The flame retardant mixture as claimed in claim 9, wherein component C) comprises telomers of the formula (III)
H(C.sub.wH.sub.2w).sub.kP(O)(OM) (C.sub.xH.sub.2x).sub.lH (III) where, in formula (III), independently of one another, k is 1 to 9, l is 1 to 9, w is 2 to 9, x is 2 to 9, and M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Fe, Zr, Zn, Ce, Bi, Sr, Mn, Li, Na, K and/or a protonated nitrogen base, and the (C.sub.wH.sub.2w).sub.k, (C.sub.xH.sub.2x).sub.l groups may be linear or branched; and/or the telomers are those of the formula (I) ##STR00004## in which R.sup.3, R.sup.4 are the same or different and are C.sub.6-C.sub.10-arylene, C.sub.7-C.sub.20-alkylarylene, C.sub.7-C.sub.20-arylalkylene and/or C.sub.3-C.sub.16-cycloalkyl or -bicycloalkyl, M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Fe, Zr, Zn, Ce, Bi, Sr, Mn, Li, Na, K and/or a protonated nitrogen base; and components A), B1) and C) are different compounds.

14. The flame retardant mixtures as claimed in claim 13, wherein, in formula (VI), w and x are each 2 or 3 and k and l are each 1 to 3 and M is Al, Ti, Fe or Zn.

15. The flame retardant mixture as claimed in claim 13, wherein the telomers are metal salts of ethylbutylphosphinic acid, dibutylphosphinic acid, ethylhexylphosphinic acid, butylhexylphosphinic acid, ethyloctylphosphinic acid, sec-butylethylphosphinic acid, 1-ethylbutyl(butyl)phosphinic acid, ethyl(1-methylpentyl)phosphinic acid, di-sec-butylphosphinic acid (di-1-methylpropylphosphinic acid), propyl(hexyl)phosphinic acid, dihexylphosphinic acid, hexyl(nonyl)phosphinic acid, propyl(nonyl)phosphinic acid, dinonylphosphinic acid, dipropylphosphinic acid, butyl(octyl)phosphinic acid, hexyl(octyl)phosphinic acid, dioctylphosphinic acid, ethyl(cyclopentylethyl)phosphinic acid, butyl(cyclopentylethyl)phosphinic acid, ethyl(cyclohexylethyl)phosphinic acid, butyl(cyclohexylethyl)phosphinic acid, ethyl(phenylethyl)phosphinic acid, butyl(phenylethyl)phosphinic acid, ethyl(4-methylphenylethyl)phosphinic acid, butyl(4-methylphenylethyl)phosphinic acid, butylcyclopentylphosphinic acid, butylcyclohexylethylphosphinic acid, butylphenylphosphinic acid, ethyl(4-methylphenyl)phosphinic acid and/or butyl(4-methylphenyl)phosphinic acid, where the metal of the metal salt comes from the group of Mg, Ca, Al, Sb, Sn, Ge, Ti, Fe, Zr, Zn, Ce, Bi, Sr, Mn, Li, Na and/or K.

16. The flame retardant mixture as claimed in claim 9, which further comprises synergists as component D), where the synergists are melamine phosphate, dimelamine phosphate, pentamelamine triphosphate, trimelamine diphosphate, tetrakismelamine triphosphate, hexakismelamine pentaphosphate, melamine diphosphate, melamine tetraphosphate, melamine pyrophosphate, melamine polyphosphates, melam polyphosphates, melem polyphosphates and/or melon polyphosphates; or melamine condensation products such as melam, melem and/or melon; or oligomeric esters of tris(hydroxyethyl) isocyanurate with aromatic polycarboxylic acids, benzoguanamine, tris(hydroxyethyl) isocyanurate, allantoin, glycoluril, melamine, melamine cyanurate, urea cyanurate, dicyandiamide and/or guanidine; or nitrogen-containing phosphates of the formula (NH.sub.4).sub.yH.sub.3-yPO.sub.4 or (NH.sub.4PO.sub.3).sub.z with y=1 to 3 and z=1 to 10 000; or aluminum phosphites, aluminum pyrophosphites, aluminum phosphonates, aluminum pyrophosphonates; or silicates, zeolites, silicas, ceramic powder, zinc compounds, e.g. zinc borate, zinc carbonate, zinc stannate, zinc hydroxystannate, zinc phosphate, zinc sulfide, zinc oxide, zinc hydroxide, tin oxide hydrate, basic zinc silicate, zinc molybdate, magnesium hydroxide, hydrotalcite, magnesium carbonate and/or calcium magnesium carbonate.

17. The flame retardant mixture as claimed in claim 16, which comprises: a) 0.0001% to 74.8% by weight of component A), b) 0.0001% to 25% by weight of component B1), c) 0.1% to 40% by weight of component C), and d) 0.1% to 40% by weight of component D), where the sum total of A), B1), C) and D) is 100% by weight, with the proviso that A), B1) and C) are different compounds.

18. The flame retardant mixture as claimed in claim 1, which comprises: a particle size of 0.01 to 1000 m, a bulk density of 50 to 1500 g/L, a tamped density of 100 g/L to 1100 g/L, an angle of repose of 5 to 45 degrees, a BET surface area of 1 to 40 m.sup.2/g, L color values of 85 to 99.9, a color values of 4 to +9, and b color values of 2 to +6.

19. The flame retardant mixture as claimed in claim 1, which comprises: a particle size of 0.5 to 800 m, a bulk density of 80 to 800 g/L, a tamped density of 600 g/L to 800 g/L, and an angle of repose of 10 to 40 degrees.

20. A process for producing flame retardant mixtures as claimed in claim 1, which comprises: a) in a process stage 1 adding 0.9 to 1.1 molecules of olefin per P onto a water-soluble salt of the hypophosphorous acid or the acid itself, b) in a process stage 2 adding 0.9 to 1.1 additional molecules of olefin per P onto the intermediate from a) to give dialkylphosphinic acid or salt thereof, c) in a process stage 3 adding 1 to 9 further olefin molecules onto 0% to 40% of the dialkylphosphinate molecules from process stage 1, so as to form telomers, with conversion of dialkylphosphinic acid, if it is formed, to a corresponding salt, d) in a process stage 4 conducting a crystallization of the intermediate from c) and a metal salt, forming a homogeneous compound, e) in a process stage 5 adding an iron compound to the intermediate from c) for a coprecipitation, and f) removing by-products and drying.

21. A process for producing flame retardant mixtures as claimed in claim 1, which comprises: a) in a process stage 1 adding 0.9 to 1.1 molecules of olefin per P onto a water-soluble salt of the hypophosphorous acid or the acid itself, b) in a process stage 2 adding 0.9 to 1.1 additional molecules of olefin per P onto the intermediate from a) to give dialkylphosphinic acid or salt thereof, c) in a process stage 3 adding 1 to 9 further olefin molecules onto 0% to 40% of the dialkylphosphinate molecules from process stage 1, so as to form telomers, with conversion of dialkylphosphinic acid, if it is formed, to a corresponding salt, and d) in a process stage 4 conducting a coprecipitation of the intermediate from c) and a metal salt (other than iron) and an iron salt.

22. A process for producing flame retardant mixtures as claimed in claim 1, which comprises: a) in a process stage 1 adding 0.9 to 1.1 molecules of olefin per P onto a water- soluble salt of the hypophosphorous acid or the acid itself, b) in a process stage 2 adding 0.9 to 1.1 additional molecules of olefin per P onto the intermediate from a) to give dialkylphosphinic acid or salt thereof, with conversion of dialkylphosphinic acid, if it is formed, to a corresponding salt, c) in a process stage 3) conducting a crystallization of the intermediate from b) and a metal salt, d) in a process stage 4 removing by-products and drying, and e) in a process stage 5 conducting a coprecipitation of the intermediate from c) and an iron salt.

23. A process for producing flame retardant mixtures as claimed in claim 1, which comprises: a) in a process stage 1 adding 0.9 to 1.1 molecules of olefin per P onto a water-soluble salt of the hypophosphorous acid or the acid itself, b) in a process stage 2 adding 0.9 to 1.1 additional molecules of olefin per P onto the intermediate from a) to give dialkylphosphinic acid or salt thereof, with conversion of dialkylphosphinic acid, if it is formed, to a corresponding salt, c) in a process stage 3 conducting a crystallization of the intermediate from b) and a metal salt, in a process stage 4 conducting a coprecipitation of the intermediate from c) and a metal salt (other than iron) and an iron salt, d) in a process stage 4 removing by-products and drying,. and e) in a process stage 5 mixing in component C).

24. The process as claimed in claim 20, wherein the iron compounds and/or iron salts used are those with anions of the seventh main group; with anions of the oxo acids of the seventh main group; with anions of the sixth main group; with anions of the oxo acids of the sixth main group; with anions of the fifth main group; with anions of the oxo acids of the fifth main group; with anions of the oxo acids of the fourth main group; with anions of the oxo acids of the third main group; with anions of the pseudohalides; with anions of the oxo acids of the transition metals; with organic anions from the group of the mono-, di-, oligo- and polycarboxylic acids, of acetic acid, of trifluoroacetic acid, propionates, butyrates, valerates, caprylates, oleates, stearates, of oxalic acid, of tartaric acid, citric acid, benzoic acid, salicylates, lactic acid, acrylic acid, maleic acid, succinic acid, of amino acids, of acidic hydroxo functions, para-phenolsulfonates, para-phenolsulfonate hydrates, acetylacetonate hydrates, tannates, dimethyldithiocarbamates, trifluoromethanesulfonate, alkylsulfonates and/or aralkylsulfonates; as elemental iron; as iron compound in the form of the fluorides, chlorides, bromides, iodides, iodate, perchlorate, oxides, hydroxides, peroxides, superoxides, sulfates, hydrogensulfates, sulfate hydrates, sulfites, peroxosulfates, nitrides, phosphides, nitrates, nitrate hydrates, nitrites, phosphates, peroxophosphates, phosphites, hypophosphites, pyrophosphates, carbonates, hydrogencarbonates, hydroxocarbonates, carbonate hydrates, silicates, hexafluorosilicates, hexafluorosilicate hydrates, stannates, borates, polyborates, peroxoborates, thiocyanates, cyanates, cyanides, chromates, chromites, molybdates, permanganates, formates, acetates, acetate hydrates, trifluoroacetate hydrates, propionates, butyrates, valerates, caprylates, oleates, stearates, oxalates, tartrates, citrates, basic citrates, citrate hydrates, benzoates, salicylates, lactates, lactate hydrates, acrylic acid, maleic acid, succinic acid, glycine, phenoxides, para-phenolsulfonates, para-phenolsulfonate hydrates, acetylacetonate hydrates, tannates, dimethyldithiocarbamates, trifluoromethanesulfonate, alkylsulfonates and/or aralkylsulfonates; and/or in the form of alloys of iron with copper, tin, nickel, chromium, molybdenum, tungsten, vanadium.

25. The process as claimed in claim 20, wherein the following are added in the process stages: initiators, free-radical initiators, photoinitiators, inhibitors, free-radical control auxiliaries, nucleating agents, cocrystallization auxiliaries, crystallization auxiliaries, strong electrolytes, wetting agents, solvents, acids, alkalis, alkaline compounds, strongly alkaline solutions, flow auxiliaries, bleaches, coupling reagents, adhesion promoters, separating agents, plastics additives, coatings additives, and flame retardants ensheathed by a flame retardant mixture comprising: 99.9999% to 87% by weight of diorganylphosphinic salts as component and 0.0001% to 13% by weight of iron as component B), where the sum total of A) and B) is 100% by weight.

26. The use of flame retardant mixtures as claimed in claim 1 as an intermediate for further syntheses, as a binder, as a crosslinker or accelerator in the curing of epoxy resins, polyurethanes and unsaturated polyester resins, as polymer stabilizers, as crop protection compositions, as sequestrants, as a mineral oil additive, as an anticorrosive, in washing and cleaning composition applications, and in electronics applications; as flame retardants, as flame retardants for clearcoats and intumescent coatings, as flame retardants for wood and other cellulosic products, as reactive and/or nonreactive flame retardant for polymers, for production of flame-retardant polymer molding compounds, for production of flame-retardant polymer moldings and/or for rendering polyester and pure and blended cellulose fabrics flame-retardant by impregnation.

27. A thermoplastic or thermoset polymer molding compound, polymer molding, polymer film, polymer filament or polymer fiber which has been rendered flame-retardant and contains 0.5% to 50% by weight of flame retardant mixtures as claimed in claim 1, 0.5% to 95% by weight of thermoplastic or thermoset polymer or mixtures thereof, 0% to 55% by weight of additives and 0% to 70% by weight of filler or reinforcement materials, where the sum total of the components is 100% by weight and where the polymer comprises thermoplastic polymers of the HI (high-impact) polystyrene, polyphenylene ether, polyamide, polyester or polycarbonate type, and blends or polymer blends of the ABS (acrylonitrile-butadiene-styrene) or PC/ABS (polycarbonate/acrylonitrile-butadiene-styrene) or PPE/HIPS (polyphenylene ether/HI polystyrene) polymer type, and/or thermoset polymers of the formaldehyde-, epoxide- or melamine-phenolic resin polymer, unsaturated polyester, epoxy resin and/or polyurethane type.

28. The thermoplastic or thermoset polymer molding compound, molding, film, filament or fiber as claimed in claim 27, which comprises further additives, which are antioxidants, UV stabilizers, gamma ray stabilizers, hydrolysis stabilizers, antistats, emulsifiers, nucleating agents, plasticizers, processing auxiliaries, impact modifiers, dyes, pigments and others.

Description

EXAMPLE 1

[0220] According to DE-A-10359815, a sodium diethylphosphinate solution with phosphorus content 7.71% by weight is prepared. To an initial charge of 2652 g of this solution at 80 C. are added a mixture of 1348 g of aluminum sulfate solution, 70 mg of 22% by weight iron(III) sulfate solution and deionized water. The crystal suspension is hot-filtered through a suction filter and washed with hot water. The moist filtered product is dried at 120 C. under a nitrogen atmosphere in a drying cabinet for about 18 h and then contains 0.2% by weight residual moisture (RM) and 18 ppm of iron.

[0221] The iron phosphinate has been coprecipitated with aluminum phosphinate.

[0222] The thermal stability and the processing window (see tables for both) are superior to pure aluminum diethylphosphinate (comparative example 16).

EXAMPLE 2

[0223] According to DE-A-10359815, a sodium diethylphosphinate solution with phosphorus content 7.71% by weight is prepared. According to example 1, it is processed using 0.2 g of 22% iron(III) sulfate solution to give a product containing 0.2% by weight RM and 52 ppm of iron. The iron phosphinate has been coprecipitated with aluminum phosphinate.

[0224] The thermal stability and the processing window (see table for both) are superior to pure aluminum diethylphosphinate (comparative example 16).

EXAMPLE 3

[0225] According to DE-A-10359815, a sodium diethylphosphinate solution with phosphorus content 7.71% by weight is prepared. According to example 1, it is processed using 3.9 g of 22% iron(III) sulfate solution to give a product containing 0.2% by weight RM and 1015 ppm of iron. The iron phosphinate has been coprecipitated with aluminum phosphinate.

[0226] The thermal stability and the processing window (see table for both) are superior to pure aluminum diethylphosphinate (comparative example 16).

EXAMPLE 4

[0227] According to DE-A-10359815, a sodium diethylphosphinate solution with phosphorus content 7.71% by weight is prepared. According to example 1, it is processed using 52 g of 22% iron(III) sulfate solution to give a product containing 0.1% by weight RM and 13701 ppm of iron. The iron phosphinate has been coprecipitated with aluminum phosphinate.

[0228] The thermal stability and the processing window (see table for both) are superior to pure aluminum diethylphosphinate (comparative example 16).

EXAMPLE 5

[0229] According to DE-A-10359815, a sodium diethylphosphinate solution containing sec-butyl ethylphosphinate (1-methylpropyl ethylphosphinate) as telomer and with phosphorus content 7.71% by weight is prepared. 2652 g of this solution are metered simultaneously with 1364 g of aluminum sulfate solution at 80 C. into deionized water. Thereafter, 70 mg of 22% iron(III) sulfate solution are introduced into the resultant excess of sodium diethylphosphinate. The crystal suspension obtained is hot-filtered through a suction filter and washed with hot water. The moist filtered product is dried at 120 C. under a nitrogen atmosphere in a drying cabinet for about 18 h and then contains 0.1% by weight residual moisture (RM), 0.2 P % of sec-butyl ethylphosphinate and 18 ppm of iron.

[0230] The telomer aluminum salt is incorporated into the crystal lattice of the aluminum diethylphosphinate containing coprecipitated iron phosphinate.

[0231] The thermal stability and the processing window (see table for both) are superior to pure aluminum diethylphosphinate (comparative example 16).

EXAMPLE 6

[0232] According to DE-A-10359815, a sodium diethylphosphinate solution containing n-butyl ethylphosphinate as telomer and with phosphorus content 7.71% by weight is prepared. 2652 g of this solution are metered simultaneously with 1364 g of aluminum sulfate solution at 80 C. into deionized water. Thereafter, 0.2 g of 22% iron(III) sulfate solution are introduced into the resultant excess of sodium diethylphosphinate. The crystal suspension is hot-filtered through a suction filter and washed with hot water. The moist filtered product is dried at 120 C. under a nitrogen atmosphere in a drying cabinet for about 18 h and then contains 0.1% by weight residual moisture (RM), 0.9 P % of n-butyl ethylphosphinate and 52 ppm of iron.

[0233] The telomer aluminum salt is incorporated into the crystal lattice of the aluminum diethylphosphinate containing coprecipitated iron phosphinate.

[0234] The thermal stability and the processing window (see table for both) are superior to pure aluminum diethylphosphinate (comparative example 16).

EXAMPLE 7

[0235] According to DE-A-10359815, a sodium diethylphosphinate solution containing n-butyl ethylphosphinate as telomer and with phosphorus content 7.71% by weight is prepared. 2652 g of this solution are metered simultaneously with 1355 g of aluminum sulfate solution at 80 C. into deionized water. 3.9 g of 22% iron(III) sulfate solution are introduced into the resultant excess of sodium diethylphosphinate. The crystal suspension is hot-filtered through a suction filter and washed with hot water. The moist filtered product is dried at 120 C. under a nitrogen atmosphere in a drying cabinet for about 18 h and then contains 0.2% by weight residual moisture (RM), 4 P % of n-butyl ethylphosphinate and 1019 ppm of iron.

[0236] The telomer aluminum salt is incorporated into the crystal lattice of the aluminum diethylphosphinate containing coprecipitated iron phosphinate.

[0237] The thermal stability and the processing window (see table for both) are superior to pure aluminum diethylphosphinate (comparative example 16).

EXAMPLE 8

[0238] According to DE-A-10359815, a sodium diethylphosphinate solution containing n-butyl ethylphosphinate as telomer and with phosphorus content 7.71% by weight is prepared. 2652 g of this solution are metered simultaneously with 1238 g of aluminum sulfate solution at 80 C. into deionized water. 52 g of 22% iron(III) sulfate solution are introduced into the resultant excess of sodium diethylphosphinate. The crystal suspension is hot-filtered through a suction filter and washed with hot water. The moist filtered product is dried at 120 C. under a nitrogen atmosphere in a drying cabinet for about 18 h and then contains 0.2% by weight residual moisture (RM), 10 P % of n-butyl ethylphosphinate and 13 783 ppm of iron.

[0239] The telomer aluminum salt is incorporated into the crystal lattice of the aluminum diethylphosphinate containing coprecipitated iron phosphinate.

[0240] The thermal stability and the processing window (see table for both) are superior to pure aluminum diethylphosphinate (comparative example 16).

EXAMPLE 9

[0241] 1364 g of aluminium sulfate solution to which 0.2 g of 22% iron(III) sulfate solution has been added are initially charged together with 3800 g of deionized water. According to DE-A-10359815, 2652 g of a sodium diethylphosphinate solution containing sec-butyl ethylphosphinate (1-methylpropyl ethylphosphinate) as telomer and with phosphorus content 7.71% by weight is prepared, and this solution is metered into the initial charge at 100 C. The crystal suspension is hot-filtered through a suction filter and washed with hot water. The moist filtered product is dried at 120 C. under a nitrogen atmosphere in a drying cabinet for about 18 h and contains 0.1% by weight residual moisture (RM), 0.1 P % of sec-butyl ethylphosphinate and 52 ppm of iron.

[0242] The sec-butyl ethylphosphinate has been coprecipitated with the aluminum diethylphosphinate and the iron diethylphosphinate as the aluminum salt, i.e. is bound in a microscopically fine, inseparable manner.

[0243] The thermal stability and the processing window (see table for both) are superior to pure aluminum diethylphosphinate (comparative example 16).

EXAMPLE 10

[0244] 1364 g of aluminium sulfate solution to which 0.23 g of 22% iron(II) sulfate solution has been added are initially charged together with 3800 g of deionized water. According to DE-A-10359815, 2652 g of a sodium diethylphosphinate solution containing n-butyl ethylphosphinate as telomer and with phosphorus content 7.71% by weight is prepared, and this solution is metered into the initial charge at 100 C. The crystal suspension is hot-filtered through a suction filter and washed with hot water. The moist filtered product is dried at 120 C. under a nitrogen atmosphere in a drying cabinet for about 18 h and contains 0.2% by weight residual moisture (RM), 0.1 P % of n-butyl ethylphosphinate and 61 ppm of iron. The n-butyl ethylphosphinate has been coprecipitated with the aluminum diethylphosphinate and the iron diethylphosphinate as the aluminum salt, i.e. is bound in a microscopically fine, inseparable manner.

[0245] The thermal stability and the processing window (see table for both) are superior to pure aluminum diethylphosphinate (comparative example 16).

EXAMPLE 11

[0246] 1364 g of aluminium sulfate solution to which 0.2 g of 22% iron(III) sulfate solution has been added are initially charged together with 3800 g of deionized water. According to DE-A-10359815, 2652 g of a sodium diethylphosphinate solution containing n-butyl ethylphosphinate and sec-butyl ethylphosphinate as telomer and with phosphorus content 7.71% by weight is prepared, and this solution is metered into the initial charge at 100 C. The crystal suspension is hot-filtered through a suction filter and washed with an amount of hot water 15 times the amount of the solids. The moist filtered product is dried at 120 C. under a nitrogen atmosphere in a drying cabinet for about 18 h and contains 0.1% by weight residual moisture (RM), 0.4 P % of n-butyl ethylphosphinate, 0.9 P % of sec-butyl ethylphosphinate and 53 ppm of iron.

[0247] The n-butyl ethylphosphinate and the sec-butyl ethylphosphinate have been coprecipitated with the aluminum diethylphosphinate and the iron diethylphosphinate as the aluminum salt, i.e. is bound in a microscopically fine, inseparable manner.

[0248] The thermal stability and the processing window (see table for both) are superior to pure aluminum diethylphosphinate (comparative example 16).

EXAMPLE 12

[0249] 1355 g of aluminium sulfate solution to which 0.39 g of 22% iron(III) sulfate solution has been added are initially charged together with 3800 g of deionized water. According to DE-A-10359815, 2652 g of a sodium diethylphosphinate solution containing n-butyl ethylphosphinate as telomer and with phosphorus content 7.71% by weight is prepared, and this solution is metered into the initial charge at 100 C. The crystal suspension is hot-filtered through a suction filter and washed with hot water. The moist filtered product is dried at 120 C. under a nitrogen atmosphere in a drying cabinet for about 18 h and contains 0.1% by weight residual moisture (RM), 4 P % of n-butyl ethylphosphinate and 1021 ppm of iron.

[0250] The n-butyl ethylphosphinate has been coprecipitated with the aluminum diethylphosphinate and the iron diethylphosphinate as the aluminum salt, i.e. is bound in a microscopically fine, inseparable manner.

[0251] The thermal stability and the processing window (see table for both) are superior to pure aluminum diethylphosphinate (comparative example 16).

EXAMPLE 13

[0252] 1355 g of aluminium sulfate solution to which 3.9 g of 22% iron(III) sulfate solution has been added are initially charged together with 3800 g of deionized water. According to DE-A-10359815, 2652 g of a sodium diethylphosphinate solution containing sec-butyl ethylphosphinate and n-butyl ethylphosphinate as telomer and with phosphorus content 7.71% by weight is prepared, and this solution is metered into the initial charge at 100 C. The crystal suspension is hot-filtered through a suction filter and washed with hot water. The moist filtered product is dried at 120 C. under a nitrogen atmosphere in a drying cabinet for about 18 h and contains 0.2% by weight residual moisture (RM), 0.9 P % of sec-butyl ethylphosphinate, 5 P % of n-butyl ethylphosphinate and 1034 ppm of iron.

[0253] The sec-butyl ethylphosphinate and the n-butyl ethylphosphinate have been coprecipitated with the aluminum diethylphosphinate and the iron diethylphosphinate as the aluminum salt, i.e. is bound in a microscopically fine, inseparable manner.

[0254] The thermal stability and the processing window (see table for both) are superior to pure aluminum diethylphosphinate (comparative example 16).

EXAMPLE 14

[0255] 830.7 g of aluminum diethylphosphinate and 22.3 g of aluminum n-butylethylphosphinate and 0.2 g of 22% iron(III) sulfate solution are initially charged in 3800 g of deionized water at 100 C. Then 2.8 g of a sodium diethylphosphinate solution with phosphorus content 7.71% by weight which have been dissolved in 3148 g of water are metered in.

[0256] The crystal suspension is filtered, washed and dried as in example 1, and then contains 0.1% by weight residual moisture (RM), 1.8 P % of n-butyl ethylphosphinate and 52 ppm of iron.

[0257] The iron diethylphosphinate has been coprecipitated onto a physical mixture of aluminum diethylphosphinate and aluminum n-butylethylphosphinate, i.e. is bound in a microscopically fine, inseparable manner.

[0258] The thermal stability and the processing window (see table for both) are superior to pure aluminum diethylphosphinate (comparative example 16).

EXAMPLE 15

[0259] 811 g of aluminum diethylphosphinate and 48.4 g of aluminum n-butylethylphosphinate and 3.9 g of 22% iron(III) sulfate solution are initially charged in 3800 g of deionized water at 100 C. Then 54 g of a sodium diethylphosphinate solution with phosphorus content 7.71% by weight which have been dissolved in 3097 g of water are metered in.

[0260] The crystal suspension is filtered, washed and dried as in example 1, and then contains 0.2% by weight residual moisture (RM), 4 P % of n-butyl ethylphosphinate and 1020 ppm of iron.

[0261] The iron diethylphosphinate has been coprecipitated onto a physical mixture of aluminum diethylphosphinate and aluminum n-butylethylphosphinate, i.e. is bound in a microscopically fine, inseparable manner.

[0262] The thermal stability and the processing window (see table for both) are superior to pure aluminum diethylphosphinate (comparative example 16).

EXAMPLE 16 (COMPARATIVE)

[0263] Aluminum diethylphosphinate with no telomer and/or iron content shows the thermal stability and processing window listed in table 1.

TABLE-US-00001 TABLE 1 Amounts used in the crystallizations [g] Amounts used Sodium Al Aluminum diethyl- sulfate Fe diethyl- Product analysis phosphinate soln. sulfate phos- Residual sec-Butyl- n-Butyl- Process- BET Tapped/ aq. soln. 4.35% soln. phinate moisture Fe ethylphos- ethylphos- Therm. ing surface tamped H2O 7.71% P Al 22% Fe Yield content content phinate phinate stability window area density Ex. [g] [g] [g] [g] [g] [g] [%] [ppm Fe] [P-%] [P-%] [ C.] [%] [m2/g] [g/L] 1 3800 2652 1364 0.07 835 0.2 18 344 4.4 1.8 600 2 3800 2652 1364 0.2 840 0.2 52 365 4.8 3.5 550 3 3800 2652 1355 3.9 845 0.2 1015 367 4.5 1.8 590 4 3800 2652 1238 52.0 835 0.1 13701 366 5.0 3.3 570 5 3800 2652 1364 0.07 845 0.1 18 0.2 350 5.0 2.0 610 6 3800 2652 1364 0.2 840 0.1 52 0.9 374 4.8 3 620 7 3800 2652 1355 3.9 842 0.2 1019 4 358 5.0 2.7 580 8 3800 2652 1238 52 830 0.2 13783 10 369 4.4 2.0 570 9 3800 2652 1364 0.2 840 0.1 52 0.1 355 4.8 2.4 590 10 3800 2652 1364 0.23 835 0.2 61 0.1 362 5.0 1.9 570 11 3800 2652 1364 0.2 835 0.1 53 0.4 0.9 355 4.6 2.7 600 12 3800 2652 1355 3.9 840 0.1 1021 4 360 4.8 3.1 570 13 3800 2652 1355 3.9 830 0.2 1034 0.9 5 360 4.6 3.0 600 16 1000 0.2 0 0 325 8 2.2 610 comp.

[0264] The inventive dialkylphosphinic salts and dialkylphosphinic telomer salts having a defined iron content have a visibly greater (wider) processing window than a diethylphosphinic salt containing no iron.

[0265] They also all exhibit very good flame retardancy in PA66 (UL 94 classification V-0).

[0266] In the above table, thermal stability was measured with the aid of thermogravimetry (TGA). The temperature reported is that at which there is 2% by weight of weight loss.

[0267] The processing window of the polymer molding compound was likewise determined by TGA. The weight loss is measured in percent by weight at 330 C. after 1 h. TGA is conducted under an air atmosphere.

[0268] In the case of the polymer molding compound, the maximum scope of the flame retardant composition of the invention is polyamide, MPP (melamine polyphosphate), glass fibers, zinc borate and wax.