Mixtures of ammonium polyphosphate and at least one soluble ionic compound containing sulfate and/or is capable of releasing sulfate ions

Abstract

The invention relates to mixtures containing, as component (A) ammonium polyphosphate and, as component (B) a soluble ionic compound which contains sulfate and/or is capable of releasing sulfate ions. The invention also relates to a method for producing such mixtures and to the use thereof.

Claims

1. An intumescent formulation for a fire protection coating, comprising a mixture of: as component (A) ammonium polyphosphate; and as component (B) lithium sulfate, magnesium sulfate, calcium sulfate, barium sulfate, iron (III) sulfate, iron (II) sulfate, titanium sulfate, cerium sulfate, melamine sulfate, urea sulfate, ammonium sulfate or a mixture thereof, wherein the mixture has a water solubility of less than 0.5 (10% suspension in water at 25° C.), wherein the mixture comprises 99.55 to 99.99% by weight of component (A); and 0.01% to 0.45% by weight of component (B), and wherein the sum total of the components is 100% by weight.

2. The intumescent formulation as claimed in claim 1, wherein the ammonium polyphosphate is of the crystal form I, II, III, IV, V, VI, a branched ammonium polyphosphate or a mixture thereof.

3. The intumescent formulation as claimed in claim 1, wherein the ammonium polyphosphate is one of the crystal form I, II, V or a mixture thereof.

4. The intumescent formulation as claimed in claim 1, wherein the ammonium polyphosphate is of the formula (NH.sub.4).sub.n+2P.sub.nO.sub.3n+1 with n≥2.

5. The intumescent formulation as claimed in claim 1, wherein the ammonium polyphosphate is of the formula (NH.sub.4).sub.n+2P.sub.nO.sub.3n+1 with n from 10 to 10 000.

6. The intumescent formulation as claimed in claim 1, wherein component (B) is ammonium sulfate.

7. The intumescent formulation as claimed in claim 1, comprising: 99.60% to 99.80% by weight of component (A); and 0.20% to 0.40% by weight of component (B), wherein the sum total of the components is 100% by weight.

8. The intumescent formulation as claimed in claim 1, comprising: 99.60% to 99.80% by weight of component (A); and 0.20% to 0.40% by weight of component (B), wherein component (B) is ammonium sulfate, and wherein the sum total of the components is 100% by weight.

9. The intumescent formulation as claimed in claim 1, wherein the mixture has: a residual moisture content of less than 0.5%, a bulk density of 0.3 to 0.9 g/cm.sup.3, a viscosity of less than 40 mPas (Brookfield DV3T, spindle 1) (10% suspension in water at 25° C.), a particle size d.sub.50 of 5 to 35 μm, a chain length of n greater than 1000 for the ammonium polyphosphate; and a pH of 4 to 8.

10. A process for producing a mixture as claimed in claim 1, comprising mixing component (A) and component (B) together, each in pulverulent or granular form, or introducing component (B) in dissolved form into component (A).

11. The process as claimed in claim 10, wherein 99.55% to 99.99% by weight of component (A) and 0.01% to 0.45% by weight of component (B) are mixed with one another, wherein component (B) is ammonium sulfate, and wherein the sum total of the components is 100% by weight.

12. A process for producing a mixture as claimed in claim 1, comprising heating equimolar amounts of ammonium dihydrogen orthophosphate and urea to a temperature of 250 to 300° C. for a period of 0.5 to 4 hours with simultaneous addition of component (B).

13. A process for producing a mixture as claimed in claim 1, comprising heating equimolar amounts of ammonium orthophosphate and urea to a temperature of 250 to 305° C. for a period of 0.1 to 4 hours under a moist ammonia atmosphere with simultaneous addition of component (B).

14. A process for producing a mixture as claimed in claim 1, comprising heating equimolar amounts of ammonium orthophosphate and urea to a temperature of 320 to 350° C. for a period of 0.1 to 4 hours under a moist ammonia atmosphere with simultaneous addition of component (B).

15. A process for producing a mixture as claimed in claim 1, comprising mixing and reacting phosphorus pentoxide, diammonium orthophosphate and component (B) together in molarity ratios of 1:1:0.01 to 0.08 in ammonia gas atmosphere over a period of 5 to 10 minutes and then successively a) conducting a polymerization reaction over a period of 15 to 45 minutes with supply of ammonia gas at a maximum reactor pressure of 490 to 980 Pa and at a minimum temperature of 180 to 200° C., b) feeding in ammonia gas at a temperature in the range from 200 to 220° C. and a minimum reactor pressure between 0 and 980 Pa for a period of 2 to 4 hours, c) separating off and working up the products obtained, wherein component (B) is ammonium sulfate.

Description

EXAMPLE 1

(1) To 2997 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 3 g of ammonium sulfate, and the mixture was mixed at 320 revolutions per minute (rpm) for 5 h.

EXAMPLE 2

(2) To 2994 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 6 g of ammonium sulfate (98%), and the mixture was mixed at 300 rpm for 5 h.

EXAMPLE 3

(3) To 2991 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 9 g of ammonium sulfate, and the mixture was mixed at 290 rpm for 5 h.

EXAMPLE 4

(4) To 2988 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 12 g of ammonium sulfate, and the mixture was mixed at 300 rpm for 5 h.

EXAMPLE 5 (COMPARATIVE)

(5) To 2985 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 15 g of ammonium sulfate, and the mixture was mixed at 300 rpm for 5 h.

EXAMPLE 6 (COMPARATIVE)

(6) To 2964 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 36 g of ammonium sulfate, and the mixture was mixed at 300 rpm for 5 h.

EXAMPLE 7

(7) To 2997 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 3 g of sulfuric acid (98%), and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 8

(8) To 2994 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 6 g of sulfuric acid (98%), and the mixture was mixed at 300 rpm for 5.5 h.

EXAMPLE 9

(9) To 2991 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 9 g of sulfuric acid (98%), and the mixture was mixed at 300 rpm for 6 h.

EXAMPLE 10 (COMPARATIVE)

(10) To 2988 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 12 g of sulfuric acid (98%), and the mixture was mixed at 300 rpm for 5 h.

EXAMPLE 11 (COMPARATIVE)

(11) To 2985 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 15 g of sulfuric acid (98%), and the mixture was mixed at 300 rpm for 6 h.

EXAMPLE 12

(12) To 2964 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 36 g of sulfuric acid (98%), and the mixture was mixed at 300 rpm for 5 h.

(13) The mixtures obtained from examples 1 to 12 were each used to produce an intumescent formulation of the following composition: 27 parts by weight of the mixtures from examples 1 to 12 10 parts by weight of Pliolite® AC 80 8 parts by weight of melamine 8 parts by weight of pentaerythritol 8 parts by weight of titanium dioxide 6 parts by weight of chloroparaffin
ad 100 parts by weight thickener (Plioway® EC-T), auxiliaries and additives (butyldiglycol acetate (BDGA), Texano®), dispersing additives, solvents (Shellsol® 100/140, xylene, methyl ethyl ketone (MEK)).

(14) The respective intumescent formulation was produced as described below: a) the solvent is initially charged at room temperature and paint additives (Disperbyk®-2163 from BYK), dispersing aids and optionally defoamer are added while stirring, b) the respective mixture from examples 1 to 12, blowing agent and carbon source, and also titanium dioxide and fillers, are scattered in while stirring at low speed, c) the thixotropic agent (Luvotic® PA20XA from Lehmann & Voss & Co.) is scattered in while stirring, d) dispersing is effected with high shear forces for at least 25 minutes while maintaining a temperature of 50° C., preferably of 55° C., for at least 10 minutes, preferably not exceeding a temperature of 60° C., e) homogeneous dispersion is effected for at least 5 minutes—peripheral speed of the dissolver disk 18-25 m/s—and the desired viscosity is established by adding solvents.

(15) To test water stability, the fire protection coating thus obtained is applied to an aluminum sheet (70×150×0.8 mm) (the layer thickness prior to drying is 1 mm) and then dried at 26° C. for 24 h. Thereafter, half the sheet is immersed longitudinally into a water bath for a further 24 h, and then blister formation on the surface is visually assessed. The evaluation is effected by photography/with computer assistance.

(16) Tables 1 and 2 indicate the proportion of the surface immersed into water that has been affected by blister formation in %. The greater the surface area affected, the lower the water stability. This is especially important for outdoor applications. If the coating is generally exposed to the moisture and weathering, good and lasting surface stability is of essential significance in order to assure smoothness of application and service life.

(17) TABLE-US-00001 TABLE 1 Exolit Ammonium AP 422 sulfate Surface area Entry (% by wt.) (% by wt.) affected in % Pure ammonium polyphosphate 100 0 92 Mixture from example 1 99.9 0.1 61 Mixture from example 2 99.8 0.2 43 Mixture from example 3 99.7 0.3 28 Mixture from example 4 99.6 0.4 35 Mixture from example 5 99.5 0.5 70 Mixture from example 6 98.8 1.2 96

(18) TABLE-US-00002 TABLE 2 Exolit Ammonium AP 422 sulfate Surface area Entry (% by wt.) (% by wt.) affected in % Mixture from example 7 99.9 0.1 60 Mixture from example 8 99.8 0.2 43 Mixture from example 9 99.7 0.3 30 Mixture from example 10 99.6 0.4 36 Mixture from example 11 99.5 0.5 71 Mixture from example 12 98.8 1.2 92

(19) A series of experiments with mixtures of ammonium polyphosphate of the I form and ammonium sulfate gave analogous results in the test for water stability to table 1 and table 2.

(20) To test storage stability, an intumescent formulation produced solely with ammonium polyphosphate (Exolit® AP 422) as prepared above was compared with one that contained a mixture of 99.7% by weight of Exolit® AP 422 and 0.3% by weight of ammonium sulfate according to example 3.

(21) For the storage test, both intumescent formulations were stored under airtight conditions at 4° C. and the viscosity was monitored and measured over a period of 365 days.

(22) TABLE-US-00003 Intumescent formulation Intumescent formulation comprising comprising ammonium mixture of 99.7% by wt. of Exolit ® polyphosphate AP 422 and 0.3% by wt. of ammonium Day (Exolit ® AP 422) only sulfate according to example 3 1 25100 mPas 23400 mPas 20 25700 mPas 22100 mPas 60 26300 mPas 22300 mPas 120 28200 mPas 23100 mPas 365 29700 mPas 24800 mPas

(23) It has been found that, surprisingly, the viscosity of an intumescent formulation of the invention comprising a mixture of 99.7% by weight of Exolit® AP 422 and 0.3% by weight of ammonium sulfate according to example 3, compared to an analogous mixture comprising pure ammonium polyphosphate, exhibits a significantly smaller rise in viscosity. A reduced viscosity facilitates the production procedure for the intumescent formulation; in addition, storage stability is increased. A lower viscosity additionally facilitates use in spraying systems.

EXAMPLE 13

(24) The mixtures from example 2 and example 3 were each used to produce an intumescent formulation according to example 2 of EP-A-1400573, except that the Exolit® APP 462 mentioned therein was replaced by equal amounts of mixture of the invention.

(25) The intumescent formulation thus produced was applied as an intumescent coating to a coated steel sheet (280×280×5 mm) and a fire test was conducted analogously to DIN 4102 Part 8, fire curve ISO 834, with a dry film thickness of 1000 μm. The result was a fire resistance time of 60 minutes with the mixture according to example 2, and of 62 minutes with the mixture according to example 3 (T.sub.critical=500° C.).

(26) The claimed mixtures of ammonium polyphosphate and a soluble inorganic compound are therefore of excellent suitability for production of effective intumescent coatings.

EXAMPLE 14

(27) To 2990 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 10 g of sodium sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 15

(28) To 2986 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 14 g of iron (II) sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 16

(29) To 2989 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 11 g of titanium oxysulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 17

(30) To 2989 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 11 g of zinc (II) sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 18

(31) To 2987 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 13 g of cerium (III) sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 19

(32) To 2993 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 7 g of lithium sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 20

(33) To 2991 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 9 g of calcium sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 21

(34) To 2992 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 8 g of aluminum sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 22

(35) To 2989 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 11 g of urea sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 23

(36) To 2985 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 15 g of melamine sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 24

(37) To 2984 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 16 g of barium sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 25

(38) To 2988 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 12 g of ammonium sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 26

(39) To 2989 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 11 g of magnesium sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 27

(40) To 2987 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 13 g of sodium sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 28

(41) To 2981 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 19 g of iron (II) sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 29

(42) To 2986 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 14 g of titanium oxysulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 30

(43) To 2985 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 15 g of zinc (II) sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 31

(44) To 2983 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 17 g of cerium (III) sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 32

(45) To 2990 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 10 g of lithium sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 33

(46) To 2988 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 12 g of calcium sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 34

(47) To 2990 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 10 g of aluminum sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 35

(48) To 2986 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 14 g of urea sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 36

(49) To 2980 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 20 g of melamine sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 37

(50) To 2979 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 21 g of barium sulfate, and the mixture was mixed at 330 rpm for 6 h.

EXAMPLE 38

(51) To 2992 g of Exolit® AP 422 in a tumbling mixer (from Heidolph) were added 8 g of magnesium sulfate, and the mixture was mixed at 330 rpm for 6 h.

(52) The mixtures obtained from examples 14 to 38 were incorporated into intumescent formulations in the same way as the mixtures of examples 1 to 12. These likewise exhibit reduced viscosity and elevated storage stability.