Aluminum Hydrogen Phosphites, A Process for Preparing Them and Their Use

1 . An aluminum hydrogenphosphite of the formula (I)

Al 2.00 (HPO 3 ) v (H 2 PO 3 ) y ×(H 2 O) z   (I)

wherein

v is 2 to 2.99,

y is 2 to 0.01 and

z is 0 to 4.

2 . An aluminum hydrogenphosphite as claimed in claim 1 , wherein

v is 2.56 to 2.99,

y is 0.9 to 0.02 and

z is 0 to 1.

3 . An aluminum hydrogenphosphite as claimed in claim 1 , wherein

v is 2.834 to 2.99,

y is 0.332 to 0.03 and

z is 0.01 to 0.1.

4 . An aluminum hydrogenphosphite as claimed in claim 1 , further comprising

a particle size of 0.1 to 1000 μm,

a solubility in water of 0.01 to 10 g/l,

a bulk density of 80 to 800 g/l and

a residual moisture content of 0.1 to 5%.

5 . A process for preparing aluminum hydrogenphosphites of the formula (I)

Al 2.00 (HPO 3 ) v (H 2 PO 3 ) y ×(H 2 O) z   (I)

wherein

v is 2 to 2.99,

y is 2 to 0.01 and

z is 0 to 4.

comprising the step of reacting, in a ratio of 2.5 to 3.5 mol, a phosphorus source with 2 mol of an aluminum source at 50 to 300° C. without using a solvent.

6 . The process as claimed in claim 5 , wherein the reaction is executed at 120 to 220° C.

7 . The process as claimed in claim 5 , wherein the aluminum source is aluminum metal, aluminum alloys, oxides, hydroxides, peroxides, peroxide hydrates, carbonates, percarbonates, mixed carbonates/hydrates, formates, acetates, propionates, stearates, lactates, ascorbates, oxalates, or aluminum salts with anions of acids having a higher vapor pressure than phosphorous acid.

8 . The process as claimed in claim 5 , wherein the phosphite source is phosphorous acid, phosphorus trioxide, phosphorus trichloride, elemental phosphorus, hypophosphorous acid or a mixture thereof.

9 . An intermediate for further synthesis, a binder, a crosslinker or accelerator in the curing of epoxy resins, polyurethanes, unsaturated polyester resins, a polymer stabilizer, a crop protection composition, a sequestrant, a mineral oil additive, an anticorrosive, a washing composition a cleaning composition or a electronic composition comprising an aluminum hydrogenphosphite of the formula (I)

Al 2.00 (HPO 3 )(H 2 PO 3 ) y ×(H 2 O) z   (I)

wherein

v is 2 to 2.99,

y is 2 to 0.01 and

z is 0 to 4.

10 . A flame retardant, a flame retardant for clearcoats and intumescent coatings, a flame retardant for wood and other cellulosic products, a reactive and nonreactive flame retardant for polymers, a flame-retardant polymer molding composition, a flame-retardant for rendering polyester and pure and blended cellulose fabrics flame-retardant by impregnation, a synergist or a synergist in flame-retardant mixtures and flame retardants comprising an aluminum hydrogenphosphite of the formula (I)

Al 2.00 (HPO 3 ) v (H 2 PO 3 ) y ×(H 2 O) z   (I)

wherein

v is 2 to 2.99,

y is 2 to 0.01 and

z is 0 to 4.

11 . A flame-retardant thermoplastic or thermoset polymer molding composition or polymer molding, film, filament or fiber comprising 0.1 to 45% by weight of an aluminum hydrogenphosphite of the formula (I)

Al 2.00 (HPO 3 ) v (H 2 PO 3 ) y ×(H 2 O) z   (I)

wherein

v is 2 to 2.99,

y is 2 to 0.01 and

z is 0 to 4, 55 to 99.9% by weight of thermoplastic or thermoset polymer or mixtures thereof, 0 to 55% by weight of additives and 0 to 55% by weight of filler or a reinforcing material, where the sum of the components is 100% by weight.

12 . A flame-retardant thermoplastic or thermoset polymer molding composition or polymer molding, film, filament or fiber comprising 0.1 to 45% by weight of a flame retardant mixture comprising 0.1 to 50% by weight of an aluminum hydrogenphosphite of the formula (I)

Al 2.00 (HPO 3 ) v (H 2 PO 3 ) y ×(H 2 O) z   (I)

wherein

v is 2 to 2.99,

y is 2 to 0.01 and

z is 0 to 4, 50 to 99.9% by weight of a flame retardant, 55 to 99.9% by weight of thermoplastic or thermoset polymer or mixtures thereof, 0 to 55% by weight of additives and 0 to 55% by weight of filler or a reinforcing material, where the sum of the components is 100% by weight.

13 . The flame-retardant thermoplastic or thermoset polymer molding composition or polymer molding, film, filament or fiber claimed in claim 10 , wherein the flame retardant is dialkylphosphinic acids and salts thereof; condensation products of melamine, reaction products of melamine with phosphoric acid, reaction products of condensation products of melamine with polyphosphoric acid or mixtures thereof; nitrogen-containing phosphates of the formulae (NH 4 ) y H 3-y PO 4 and (NH 4 PO 3 ) z , where y is 1 to 3 and z is 1 to 10 000; benzoguanamine, tris(hydroxyethyl) isocyanurate, allantoin, glycoluril, melamine, melamine cyanurate, dicyandiamide, guanidine; magnesium oxide, calcium oxide, aluminum oxide, zinc oxide, manganese oxide, tin oxide, aluminum hydroxide, boehmite, dihydrotalcite, hydrocalunnite, magnesium hydroxide, calcium hydroxide, zinc hydroxide, tin oxide hydrate, manganese hydroxide, zinc borate, basic zinc silicate zinc stannate or mixtures thereof.

14 . The flame-retardant thermoplastic or thermoset polymer molding composition or polymer molding, film, filament or fiber as claimed in claim 10 , wherein the flame retardant is melam, melem, melon, dimelamine pyrophosphate, melamine polyphosphate, melam polyphosphate, melon polyphosphate, melem polyphosphate and/or mixed poly salts thereof, ammonium hydrogenphosphate, ammonium dihydrogenphosphate, ammonium polyphosphate or mixtures thereof.

15 . The flame-retardant thermoplastic or thermoset polymer molding composition or polymer molding, film, filament or fiber as claimed in claim 10 , wherein the flame retardant is aluminum hypophosphite, zinc hypophosphite, calcium hypophosphite, sodium phosphite, monophenylphosphinic acid and salts thereof, mixtures of dialkylphosphinic acids and salts thereof and monoalkylphosphinic acids and salts thereof, 2-carboxyethylalkylphosphinic acid and salts thereof, 2-carboxyethylmethylphosphinic acid and salts thereof, 2-carboxyethylarylphosphinic acid and salts thereof, 2-carboxyethylphenylphosphinic acid and salts thereof, oxa-10-phosphaphenanthrene (DOPO) and salts thereof and adducts onto para-benzoquinone, or itaconic acid and salts thereof.