Compositions comprising ammonium polyphosphates

Abstract

The invention relates to compositions comprising as component (A) 0.1% to 99.9% by weight of phase II ammonium polyphosphate and as component (B) 0.1% to 99.9% by weight of phase I and/or phase III, IV, V and/or VI ammonium polyphosphate, where the sum total of the components is 100% by weight, and to the use thereof in intumescent coatings.

Claims

1. A composition comprising as component (A) 65% to 92% by weight of phase II ammonium polyphosphate and as component (B) 8% to 35% by weight of phase I ammonium polyphosphate, where the sum total of the components is 100% by weight, and wherein the composition has: a residual moisture content of less than 0.5%, measured according to ISO 760, a bulk density of 0.3 to 0.9 g/cm.sup.3, a water solubility of less than 1.5%, measured as a 10% suspension in water at 25 C., a viscosity of less than 40 mPas, measured by Brookfield DV3T, speed 50 rpm, spindle 1, a particle size d.sub.50 of 5 to 50 m, measured by laser diffraction, a particle size d.sub.90 of 10 to 60 m, measured by laser diffraction, and a pH of 4 to 8, measured as a 10% suspension in water at 25 C.

2. The composition according to claim 1, wherein the component A is a phase II ammonium polyphosphate having the formula (NH.sub.4).sub.n+2P.sub.nO.sub.3n+1 with n=300 to 100 000.

3. The composition according to claim 1, wherein the component A is a phase II ammonium polyphosphate having the formula (NH.sub.4).sub.n+2P.sub.nO.sub.3n+1 with n=1000 to 25 000.

4. The composition according to claim 1, wherein the component B is a phase I ammonium polyphosphate having the formula (NH.sub.4).sub.n+2P.sub.nO.sub.3n+1 with n=5 to 100.

5. The composition according to claim 1, wherein the ammonia polyphosphates have been microencapsulated with at least one selected from the group consisting of organofunctional (poly)silanes; (poly)siloxanes; (poly)silazanes; modified waxes; polyurethane; polyepoxides; urea-formaldehyde resins; melamine-formaldehyde resins; and emulsions based on (meth)acrylate resins, styrene/acrylate copolymers, urethanes, ethylene/nonyl acetate copolymers, and/or rubber.

6. The composition according to claim 2, wherein the component B is a phase I ammonium polyphosphate having the formula (NH.sub.4).sub.n+2P.sub.nO.sub.3n+1 with n=5 to 100.

7. The composition according to claim 1, further comprising up to 10% by weight, based on the amount of the components (A) and (B), of ammonium sulfate, triethylammonium sulfate, tetramethylammonium sulfate, trimethylammonium sulfate, dimethyl sulfate, diethyl sulfate, dipropyl sulfate, sodium octylsulfate, sodium decylsulfate, sodium octadecylsulfate, lauryl sulfate, urea sulfate, melamine sulfate, hydroxylamine sulfate, hydrazine sulfate, potassium sulfate, potassium hydrogensulfate, sodium sulfate, sodium hydrogensulfate, magnesium sulfate, magnesium hydrogensulfate, calcium sulfate, calcium hydrogensulfate, barium sulfate, potassium aluminium sulfate, aluminium sulfate, iron (III) sulfate, iron (II) sulfate, cobalt sulfate, titanium sulfate, zinc sulfate, tin sulfate, cerium sulfate, lithium sulfate, trimethylsulfonium methylsulfate, or mixtures thereof.

8. A product comprising the composition according to claim 1, wherein the product is a plug connector, a current-bearing component in a power distributor, a circuit board, a potting compound, a power connector, a circuit breaker, a lamp housing, an LED lamp housing, a capacitor housing, a coil element, a ventilator, a grounding contact, a plug, an in/on printed circuit board, a housing for a plug, a battery housing, a cable, a flexible circuit board, a charging cable, a motor cover, or a textile coating.

9. A fire-resistant coating steel, wood, a wood-based material, paper, mineral wool, plasterboard, plastic, metal, an alloy, fabric made of synthetic or natural fibres, a solder mask, an electrical switch or a circuit wherein the fire-resistant coating comprises the composition according to claim 1.

10. A coating for a steel construction, the coating comprising the composition according to claim 1, wherein the steel construction is a steel beam, a steel support, a ceiling, a wall, a cable, a pipe, a conduit, a cable, a combination bulkhead, a door, a curtain, a smoke barrier, a blind, a safety cabinet, or an installation cabinet.

11. A fire-resistant coating comprising the composition according to claim 1 as a foam-forming substance and at least one selected from the group consisting of one or more film-forming binders; one or more blowing agents; one or more carbon-forming substances; one or more auxiliaries; one or more additives; one or more dispersing additives and one or more solvents.

12. A fire-resistant coating comprising 5% to 40% by weight of the composition according to claim 1 as a foam-forming substance, 5% to 69.4% by weight of a film-forming binder, 5% to 25% by weight of a blowing agent, 5% to 25% by weight of a carbon-forming substance, 5% to 40% by weight of auxiliaries and additives, 0.5% to 10% by weight of a thickener, 0.1% to 10% by weight of dispersing additives, and 10% to 40% by weight of one or more solvents, wherein the components sum to 100% by weight.

13. The fire-resistant coating according to claim 12, wherein the film-forming binder comprises at least one selected from the group consisting of one or more copolymers based on styrene and an acrylic ester; one or more copolymers based on an acrylic ester; a vinyltoluene/acrylate copolymer; one or more styrene/acrylate polymers; one or more homopolymers based on vinyl acetate; one or more copolymers based on vinyl acetate; a copolymer of ethylene and vinyl chloride; one or more copolymers based on vinyl acetate and the vinyl ester of a long-chain branched carboxylic acid; one or more copolymers based on vinyl acetate and a di-n-butyl maleate ester esters or an acrylic ester; one or more vinyl/acrylate copolymers; one or more self-crosslinking polyurethane dispersions; terpenes and polyterpenes; the blowing agent is at least one selected from the group consisting of melamine, melamine-formaldehyde condensate, guanidine or a salt thereof, a melamine condensation product and dicyaniamide; the carbon-forming substance is at least one selected from the group consisting of starch, modified starch, polyhydric alcohols, and a thermoplastic or thermoset polymer resin binder; the auxiliaries and additives are at least one selected from the group consisting of glass fibres, mineral fibres, metal fibres, carbon fibres, kaolin, talc, aluminium oxide, aluminium hydroxide, magnesium hydroxide or other metal oxides, precipitated silicas, silicates and pulverized celluloses; the thickener is at least one selected from the group consisting of cellulose, silicas, bentonites, castor oil derivatives, fat derivatives, polyamides, poly(meth)acrylates, polyacrylamides, polyethers, polyurethanes, polyvinylalcohols, polyvinylpyrrolidones and sugar polymers; the dispersing additive is an alkylphenol ethoxylate, a polyacrylic acid, or a polyurethane; and the one or more solvents are selected from aromatic hydrocarbons, alcohols, ketones, alkanoic esters, and polyethers.

14. The fire-resistant coating according to claim 13, wherein the carbon-forming substance comprises one or more polyhydric alcohols selected from tripentaerythritol, polycondensates of pentaerythritol, mixtures of pentaerythritol-based esters with polyhydric alcohols, polyvinylacetate, polyvinylalcohol, sorbitol, and ethylene oxide-propylene oxide polyhydric alcohols.

Description

(1) The mixtures according to the invention may also be used correspondingly in or on textiles, without impairing the properties thereof.

(2) The mixtures according to the invention may be applied to flexible, especially textile, materials in random distribution or in a particular pattern, for example in a dot pattern. Such textiles are used, for instance, in the interior fitout of hotels, theatres and conference centres, and in modes of transport (bus, train, car, aircraft etc.).

(3) The mixtures according to the invention can be used together with other flame retardants as described, for instance, under Flammschutzmittel in Rmpps Chemie-Lexikon, 9th ed. (1996), pages 1369 to 1371.

(4) Overall, the mixtures according to the invention, alone or acting with other substances, may have carbonization-promoting, fire-smothering, barrier layer-forming, insulating layer-forming or some other kind of action.

(5) For all aforementioned applications in and on polymers, especially polyolefins, and in or for insulating layer-forming intumescent coatings and textiles, it is possible to add further additives, especially antioxidants, antistats, blowing agents, further flame retardants, heat stabilizers, impact modifiers, processing auxiliaries, lubricants, light stabilizers, anti-dripping agents, compatibilizers, reinforcers, fillers, nucleating agents, additives for laser marking, hydrolysis stabilizers, chain extenders, pigments and/or plasticizers.

(6) The intumescent formulationsthen later applied as fire protection coatingswere produced as follows: a) the solvent or solvent mixture is initially charged at room temperature and the respective resin is dissolved therein while stirring, then coatings additives such as dispersing additives and optionally defoamers are added while stirring, b) foam-forming substance, blowing agent and carbon-forming substance, and also auxiliaries and additives (for example titanium dioxide, fibres and fillers), are sprinkled in while stirring at low speed, c) thixotropic agent is sprinkled in with stirring, d) dispersed for at least 25 minutes with high shear forces while maintaining a temperature of 50 C. to 60 C., e) homogeneously dispersed for at least 5 minutes and the desired viscosity is established by addition of solvent or solvent mixtures.

(7) These formulations may be used, for example, in the production process according to the invention for an insulating layer-forming fire-retardant coating. In this case, a silicone resin emulsion (binder) is mixed with an agent that forms foam in the event of fire and optional further auxiliaries and additives in a high-shear dissolver, and adjusted to the desired consistency.

(8) The coating composition of the present invention may be applied directly to the surface to be coated or via a primer coating layer. The coating composition is typically applied in liquid form at temperatures between 10 and 60 C. The application can be effected, for instance, by airless spraying, casting (used in moulds), painting or trowelling.

(9) The coating composition according to the invention may be applied to various substrates. Preference is given here to steel and aluminium substrates, and composite materials, for instance glass fibre-reinforced plastics.

(10) The invention is elucidated without limitation in the examples which follow.

(11) First of all, mixtures of ammonium polyphosphates are produced by mixing the amounts of crystal phase II ammonium polyphosphate apparent from table 1 with the respective amounts of crystal phase I ammonium polyphosphate in a tumbling mixer (from Heidolph) at 320 revolutions per minute (rpm) for 5 h.

(12) Pure crystal phase II ammonium polyphosphate was used in example 1.

(13) Pure crystal phase I ammonium polyphosphate was used in example 11.

(14) The mixtures thus obtained show the properties reproduced in table 1.

(15) TABLE-US-00001 TABLE 1 Properties of APP mixtures APP APP Viscosity, Acid number Water Loss of Loss of mass, phase II phase I 10% Conductivity (AN) solubility mass, 2% 300 C. % by wt. % by wt. [mPa*s] [S/cm] pH [mg KOH/g] [%] C. % Example 1 100.0 0.0 9.7 1197 6.67 0.20 0.33 319.6 0.82 Example 2 90.0 10.0 5.2 2748 5.96 1.52 0.85 311.3 1.39 Example 3 87.5 12.5 4.8 3268 5.84 2.00 1.00 306.0 1.54 Example 4 85.0 15.0 4.4 3620 5.79 2.12 1.10 302.0 1.79 Example 5 82.5 17.5 4.6 3971 5.76 2.76 1.24 293.0 2.38 Example 6 80.0 20.0 4.4 4302 5.70 3.08 1.31 288.0 2.63 Example 7 75.0 25.0 4.4 4896 5.56 3.72 1.44 296.3 2.28 Example 8 67.0 33.0 4.3 5806 5.45 4.88 1.78 302.6 1.80 Example 9 50.0 50.0 4.2 7709 5.50 >5 2.35 299.0 2.06 Example 10 25.0 75.0 4.2 10240 5.50 >5 3.07 293.1 2.49 Example 11 0.0 100.0 4.3 12380 5.54 >5 3.55 293.6 2.55

(16) The above values were determined as follows:

(17) Viscosity

(18) For determination of viscosity, a 10% by weight suspension of the respective product from examples 1 to 11 was prepared in water at 25 C. and stirred. Viscosity was determined by means of a Brookfield viscometer to DIN ISO 2555 (spindle 61, 100 rpm).

(19) Conductivity

(20) For determination of pH, a 10% by weight suspension of the respective product from examples 1 to 11 was prepared in water at 25 C. and stirred for 5 minutes. Conductivity was determined by potentiometry (from Knick, model 703 conductometer)

(21) pH

(22) For determination of pH, a 10% by weight suspension of the respective product from examples 1 to 11 was prepared in water at 25 C. and stirred for 5 minutes. The pH was determined by means of potentiometry (Metrohm, LL Aquatrode Plus WOC).

(23) Acid Number

(24) For determination of acid number, a 10% by weight suspension of the respective product from examples 1 to 11 was prepared in water at 25 C. and stirred for 5 minutes. The acid number was determined to ISO 2114.

(25) Water Solubility

(26) A 10% by weight suspension of the ammonia polyphosphate or mixtures thereof was prepared in water at 25 C., and stirred and filtered. The dry residue of the filtrate based on the amount used (10% suspension) corresponds to the water solubility of this ammonium polyphosphate.

(27) Loss of Mass

(28) Loss of mass can be represented in various ways: 1) Temperature ( C.) for a 2% loss of mass 2) Loss of mass at 300 C. in %

(29) Loss of mass was determined under a nitrogen atmosphere by thermogravimetry by means of an MA35M-230N instrument from Sartorius.

(30) The bulk density of the flame retardant mixture was determined to EN ISO; DIN 53468 at 25 C.

(31) The particle size d.sub.50 was determined with the aid of a Malvern Mastersizer.

(32) It is apparent from examples 1 to 11 in table 1 that some properties of the products therein are adversely affected by the addition of phase I ammonium polyphosphate to phase II ammonium polyphosphate. For example, there is a rise in solubility to more than 3%, and a significant increase in conductivity. As a further disadvantage, there is a rise in the acid number to more than 5 mg KOH/g and a decrease in thermal stability when there is an increase in the phase I ammonium polyphosphate content in the mixture.

(33) When corresponding coatings are used in areas exposed to weathering or other outside influences, the effect of moisture can result in leaching of ammonium polyphosphate, which is no longer available for the intumescence reaction. This is expected to result in lowering of the intumescent action. For that reason, it is productive to keep the APP solubility low.

(34) The elevated salt concentration in solution which is associated with the solubility of short-chain ammonium (poly)phosphates can be illustrated, inter alia, by the determination of the conductivity.

(35) In addition, the high salt burden during the storage of intumescent systems with aqueous binders, through disruption of dispersion stability, can lead to an unwanted shortened storage stability, manifested by an irreversible increase in viscosity.

(36) For instance, in the case of incorporation of examples 1, 4 and 6 into the intumescent formulation described in WO2017153227A1, good compatibility was observed.

(37) By comparison with the use of pure phase II APP (example 1), in the case of examples 4 and 6, it was not possible to detect any increase in viscosity in the end product after 24 h. It was not possible to observe any increase in the fire resistance time (dry layer thickness of 2000 m) of the intumescent coatings that have been produced with the crystal phase mixtures (examples 4 and 6). The foam characteristics additionally showed slight inhomogeneities and reduced stability. Especially in the case of application of relatively high layer thicknesses, this can lead to detachment of the foam during the fire test.

(38) TABLE-US-00002 FRT FRT Viscosity (up to 300 C., (up to 500 C., Intumescent formulation (mPas) min) min) Produced from example 1 12400 51 104 Produced from example 4 12450 51 105 Produced from example 6 12650 52 103
If, by contrast, the mixtures of the invention are used in solvent-based intumescent coatings, a distinct rise in insulating action is observed.

(39) The products from examples 1 and 4 were used to produce solution-based intumescent formulations of examples 12 and 13.

EXAMPLE 12

(40) The ammonium polyphosphate from example 1 was used to produce an intumescent formulation of the following composition: 28 parts by weight of ammonium polyphosphate from example 1, 10 parts by weight of resin (Omnova, Pliolite Ultra 100), 8 parts by weight of melamine (OCI, Melafine), 8 parts by weight of pentaerythritol (Perstorp, Charmor PT 40), 9 parts by weight of titanium dioxide (Cristal, Tiona 696), 6 parts by weight of chloroparaffin (Dover Chemicals, Hordaresin NP 70), ad 100 parts by weight of thickener (Luvotix VP 031), Auxiliaries and additives (butyldiglycol acetate (BDGA), Texanol), dispersing additives, paint additives, solvents (Shellsol 100/140, xylene).

EXAMPLE 13

(41) The procedure was as in example 12, except that, rather than 28 parts by weight of ammonium polyphosphate from example 1, 28 parts by weight of a mixture of phase II ammonium polyphosphate (85% by weight) and phase I ammonium polyphosphate (15% by weight) from example 4 was used.

(42) The respective intumescent formulation in Examples 12 and 13 was produced as follows: a) The solvent is initially charged at room temperature, and paint additives (Disperbyk-2163 from BYK), dispersing aids and optionally defoamers are added while stirring, b) the respective mixture from example 1 or 4, blowing agents, carbon source, titanium dioxide, fillers are sprinkled in while stirring at low speed, followed by the thixotropic agent, c) the mixture is dispersed with high shear forces for 20 to 60 minutes while maintaining a temperature of 30 to 70 C., and then the desired viscosity is established by addition of solvents at low shear forces.

(43) The intumescent formulations thus produced were applied as intumescent coatings to a coated steel plate (S235JR no. 1.0122 to Standard EN 10025-2:2004; dimensions: 2802805 mm), and a fire test was conducted analogously to DIN 4102 Part 8, fire curve ISO 834, with a dry film thickness of 2000 m. FIG. 1 shows the progression of the temperature of the reverse side of the plate as a function of time.

(44) It was found here that, surprisingly, the time until attainment of a temperature on the reverse side of the plate of T.sub.critical=500 C., in the case of use of the mixture from example 4, was significantly higher at 109 minutes compared to the pure substance from example 1 at 100 minutes. This means that, in the case of the use according to the invention, the critical softening temperature of the steel is reached only at a later juncture and hence the protective action is more efficient. The structural integrity of the steel structure can thus be maintained for longer.

(45) This is thus a gain in performance of 9%. The attainment of a temperature on the reverse side of only 300 C. takes 32 min in the case of example 1, and 48 min in the case of example 4; this means an increase in the fire protection time by 50%.

(46) If, as in FIG. 2, the temperature differential of the temperature on the reverse side of the steel for examples 12 and 13 is plotted over time, it is found that the insulating effect of example 13 is higher over the entire progression of the fire. The maximum temperature differential of 45 C. is observed after a time of about 27 min.

(47) With the inventive mixtures from examples 12 and 13, inter alia, a start reaction already occurs at lower temperature compared to example 1, as a result of which there is an earlier (faster) onset of insulating action, and the substrate coated with the intumescent formulations according to the invention can be much better thermally insulated. When the systems described are used in structural steel construction, this enables longer-lived and/or more efficient fire protection systems. As a result of a longer fire resistance time, residents of a building can leave it over a longer period of time in the event of fire, and firefighters are able to fight the fire in a safe environment.

(48) The intumescent formulation according to the invention, on account of the earlier onset of insulating action, can now be used to render substrates fire-resistant that have not been protectable from heat to date owing to their low melting point. For instance, it is also possible to protect polymers and other substrates that soften even at low temperatures (e.g. 300 C.) or release combustible and/or toxic pyrolysis gases.

(49) The advantages of the intumescent formulations according to the invention are apparent from another point of view as well:

(50) TABLE-US-00003 TABLE 2 Measurement of the fire resistance time of the products from example 1 and example 4 Mixture of phase II ammonium polyphosphate Difference in time Phase II ammonium (85% by wt.) and phase between the products Increase in the duration polyphosphate from I (15% by wt.) from from example 1 and of protection in the example 1 (comparison) example 4 Time until example 4 for case of use of the Time until attainment attainment of the attainment of the product from example 4 T of the temperature temperature specified temperature compared to example 1 [ C.] specified t [min] t [min] specified in % 200 9 9 0 0 225 12 17 5 42 250 17 29 12 71 275 26 44 14 69 300 39 60 21 54 325 63 76 13 21

(51) For example, a substrate temperature of 250 C. is reached after only 17 minutes in example 1 (comparison), and not until 29 minutes in inventive example 4. Thus, the intumescent coating according to the invention is almost twice as effective as pure phase II ammonium polyphosphate within the appropriate temperature range.

(52) Thus, it is possible to prevent passage of fire very much more efficiently in the case of non-metal-based substrates, for instance thermoplastics, which often have melting points or breakdown temperatures of 300 C. or less. Practical examples here are, for example, structural material panels such as roof panels, partition walls etc., or else composite materials that are used in critical environments (battery housing or pressurized hydrogen storage facilities).

(53) The higher fire resistance times at lower temperatures resulting from the use of the mixture according to the invention advantageously lead to material savings; it is likewise possible to apply a lower layer thickness for achievement of the same effect.

(54) The percentage increase in performance is 71% at 250 C. within a comparatively low temperature range.

(55) The inventive mixtures of ammonium polyphosphates of different crystal phases are therefore of excellent suitability for production of faster-acting intumescent coatings, which additionally have enhanced material efficiency.

(56) The intumescent coatings of examples 12 and 13 that are based on examples 1 and 4 were applied to panel materials made of various plastics, and fire tests were conducted to DIN 4102 Part 8, fire curve ISO 834, with a dry film thickness of 2000 m.

EXAMPLE 14

(57) Application to Ultramid A3K (BASF; melting temperature to ISO 11357: 260 C.): The critical softening temperature of 260 C. of the polymer was reached after only 21 minutes with the intumescent formulation for example 12, but only after 35 minutes with the inventive intumescent formulation from example 13. It follows that the fire resistance time is 67% longer when the intumescent formulation according to the invention is used.

EXAMPLE 15

(58) Application to a Makrolon 2205 Polycarbonate Panel (Covestro; Melting Temperature to ISO 11357: 300 C.):

(59) The critical softening temperature of 300 C. of the polymer was reached after only 37 minutes with the intumescent formulation for example 12, but only after 58 minutes with the inventive intumescent formulation from example 13. It follows that the fire resistance time is 57% longer when the intumescent formulation according to the invention is used.

EXAMPLE 16

(60) Application to a Glass Fibre-Filled Composite Panel Produced In-House (DICY-Cured Bisphenol a Epoxy Resin):

(61) The critical breakdown temperature of 320 C. of the substrate was reached after only 62 minutes with the intumescent formulation for example 12, but only after 74 minutes with the inventive intumescent formulation from example 13. It follows that the fire resistance time is 19% longer when an intumescent formulation according to the invention is used.

EXAMPLE 17

(62) Application to an Aluminium Panel

(63) The critical softening temperature of 320 C. of the substrate was reached after only 62 minutes with the intumescent formulation for example 12, but only after 74 minutes with the inventive intumescent formulation from example 13. It follows that the fire resistance time is 19% longer when an intumescent formulation according to the invention is used.

(64) The mixture from inventive example 4 was also used for production of solvent-based intumescent formulations using the following resins (table 3): Example 18: Styrene-acrylate copolymerPliolite Ultra 100 (Omnova/Synthomer) Example 19: Methacrylate copolymerDianal Tb 080 (Evonik) Example 20: MethacrylateDegalan Lp 65/11 (Evonik) Example 21: Styrene-acrylate copolymerPliolite Ac 80 (Omnova/Synthomer) Example 22: methacrylateViacryl Sc 124/50Ws (Alinex) Example 23: MethacrylateDegalan Lp 63/11 (Evonik)

(65) TABLE-US-00004 TABLE 3 Solvent-based intumescent formulations with various resins Time until attainment Gain in % of the compared temperature to use of T [ C.] specified t [min] example 1 Pliolite Ultra 100 300 44 42 Dianal TB 080 300 60 20 Dianal TB 080.sup.1 300 48 37 Degalan LP 65/11 300 50 43 Pliolite AC 80 300 62 48 Viacryl SC 124/50WS 300 58 66 Degalan LP 63/11 300 65 20 Pliolite Ultra 100 500 113 14 Dianal TB 080 500 121 6 Dianal TB 080 123 8 Degalan LP 65/11 500 127 10 Pliolite AC 80 500 122 20 Viacryl SC 124/50WS 500 124 5 Degalan LP 63/11 300 113 0 .sup.1Using example 7

(66) Table 3 describes the variability of the flame retardant mixture according to the invention. Even though no extension of the FRT up to 500 C. was observed in some cases, the earlier activation is manifested by an earlier onset of start reaction across the board.

(67) In all experiments, moreover, the preferred foam properties with regard to surface adhesion, expansion, homogeneity and pore size were maintained.

(68) It was found here that the inventive mixture from example 4 in the respective intumescent formulation according to the invention leads to longer times in each case until attainment of the critical temperature compared to the mixture from example 1.

(69) The inventive mixtures of phase II ammonium polyphosphates with phase I ammonium polyphosphates are therefore of excellent suitability for production of efficient intumescent formulations.