FLAME-RETARDANT AND LATENT HARDENER COMPOSITION, A METHOD FOR MAKING FLAME-RETARDED WOOD AND CELLULOSE-FIBER BASED COMPOSITES AND BOARDS AND FLAME-RETARDED WOOD AND CELLULOSE-FIBER BASED BOARDS

Abstract

Provided is a flame retardant and latent hardener composition including a blend of 30-100% (by weight based on total solids) of diammonium hydrogen phosphate, and dihydrogen phosphate, 0-50% (by weight based on total solids) of monoammonium. The flame-retardant/hardener composition is prepared as a solid blend or a liquid composition, the liquid composition being an aqueous composition including a liquid aqueous solution of the contents ranging from 25% w/w to 80% w/w. Methods for making flame retarded fiber boards using the composition as flame retarder and a hardener for the resin used in the production of the boards are also provided.

Claims

1-12. (canceled)

13. A flame-retardant and latent hardener composition comprising a blend of diammonium hydrogen phosphate and monoammonium dihydrogen phosphate, wherein the blend of DAP and MAP (in weight ratios) ranges from 95% DAP/5% MAP to 60% DAP/40% MAP, and wherein the latent hardener and flame-retardant composition is prepared as a solid blend or a liquid composition, the liquid composition being an aqueous composition comprising a liquid aqueous solution of the contents ranging from 25% w/w to 80% w/w of the blend.

14. The flame-retardant and latent hardener composition according to claim 13, wherein the blend of DAP and MAP (in weight ratios) ranges from 90% DAP/10% MAP to 70% DAP/30% MAP, or from 85% DAP/15% MAP to 75% DAP/25% MAP.

15. The flame-retardant and latent hardener composition according to claim 13, further comprising from 0.1 up to 15% (by weight of total solids) of one or more acids selected from the group consisting of organic acid, C.sub.2-C.sub.7 organic acid, citric acid, formic acid, acetic acid, malic acid, tartaric acid, oxalic acid, lactic acid, butyric acid, strong acid, hydrochloric acid and any mixtures thereof.

16. The flame-retardant and latent hardener composition according to claim 13, further comprising 10-90% (by weight of total solids) of one or more monobasic or dibasic sodium or potassium phosphate, or any mixtures thereof.

17. The flame-retardant and latent hardener composition according to claim 13, further comprising from 0.1 up to 10% (by weight based on a solids basis) of one or more additives selected from sodium benzoate, potassium benzoate, sodium sorbate, potassium sorbate, sodium salicylate, potassium salicylate, Allura red, carmine, colorant, and any mixtures thereof.

18. A method for fireproofing or flameproofing wood composite boards selected from the group including medium or high density fiber boards or particle boards, during production of the boards, in which wood fibers or wood particles are passed from a storage and to a press via a blow line, and wherein a binder is added to the wood fibers or wood particles by mixing the binder into the fiber or particles by injecting, spraying or blending the binder into fiber or particle mix, in the blow line, resin blending of resin mixer and subsequently pressing the blend in a press to obtain the final wood composite board, and wherein the method further comprises adding a flame-retardant composition to the wood fibers or wood particles, by a. injecting a liquid aqueous flame-retardant and latent hardener composition according to claim 13, to the blow line that passes the wood fibers or wood particles from the storage and to the press, and where the liquid aqueous flame-retardant composition is added to the blow line in parallel to the binder, or b. adding a solid blend of the flame-retardant and latent hardener composition to the wood fibers or wood particles, parallel to the binder, in an intermediate mixing step provided between a refiner and the forming and hot-pressing steps in board production.

19. The method for fireproofing or flameproofing wood composite boards according to claim 18, wherein the binder used in the board is a thermosetting resin binder, that is cured by an acid catalyst, and wherein the thermosetting resin comprises a resin selected from a formaldehyde cross-linked resin binder, Urea Formaldehyde, Melamine Formaldehyde, Melamine Urea Formaldehyde, Melamine Urea Phenol Formaldehyde, and mixtures thereof, and where the mix of resin and wood fibers or wood particles are cured in a hot-press.

20. The method for fireproofing or flameproofing wood composite boards according to claim 18, wherein the acid catalyst is provided by the flame-retardant composition.

21. The method for fireproofing or flameproofing wood composite boards according to claim 18, wherein the flame-retardant and latent hardener composition is added to the wood fibers or particles in an amount corresponding to from 15 kg per m3 of finished product up to 100 kg/m3.

22. A method for fireproofing or flameproofing particle boards or oriented strand boards during production of the boards, in which wood particles or strands are passed from a storage and to a press via a resin mixing or blending chamber, which can be a resin blending section at the end of a rotary drier, and wherein a binder is added to the wood particles by mixing the binder into the particles or particles by injecting the binder and subsequently pressing the blend in the press to obtain the final wood composite board, and wherein the method further comprises adding a flame-retardant composition to the wood fibers or wood particles, by a. injecting a liquid aqueous flame-retardant and latent hardener composition according to claim 13, into the resin blender or resin blending section of a drier that transfers the wood fibers or wood particles from the storage and to the press, and where the liquid aqueous flame-retardant and latent hardener composition is added in parallel to the binder, or b. adding a solid blend of the flame-retardant and latent hardener composition to the wood fibers or wood particles in an intermediate mixing step provided between a refiner and the forming and hot-pressing steps in board production.

23. A method for fireproofing or flameproofing boards made with organic material/materials, fibers or particles selected from the group of wood fibers, wood particles, wood strands, plant particles and material selected from seeds, husks, straw, shells of nuts or seeds or mixtures thereof or glued boards comprising one or more layers of textiles or textile fibers, or resin boards comprising a resin matrix with dispersed fibers and/or particles of wood fibers, wood chips, wood strands, one or more layers of textiles, textile fibers, plant particles selected from seeds, husks, shells of nuts or seeds and/or mixtures thereof, wherein a fireproofing or flameproofing composition is induced to the organic material during production of the boards, in which organic material is passed from a storage and to a board forming station via a resin mixing or blending chamber, which can be a resin blending section at the end of a rotary drier, and wherein a binder or a matrix forming resin is added to the organic material by mixing the binder or resin into the organic material by injecting the binder or resin and subsequently forming the blend into boards to obtain the final composite board containing the organic material, and wherein the method further comprises adding a flame-retardant composition to the organic material, by a. injecting a liquid aqueous flame-retardant and latent hardener composition according to claim 13 into the organic material and where the liquid aqueous flame-retardant and latent hardener composition is added prior to and/or in parallel to the binder or the matrix forming resin, b. adding a solid blend of the flame-retardant and latent hardener composition to the organic material in an intermediate mixing step provided between the storage or a refiner and the board forming steps in a board production line, or c. injecting a liquid aqueous flame-retardant and latent hardener composition onto one or more layers of textiles during transfer from the storage and to the board forming station, and where the liquid aqueous flame-retardant and latent hardener composition is added prior to and/or in parallel to the binder or the matrix forming resin.

24. A fire retarded wood based composite board obtainable by the method according to claim 23, wherein the wood the fire retarded wood based composite board is selected from a fiber board, a low density fiber board, a medium density fiber board, a high density fiber board, a particle board or a oriented strand board, a board comprising plant particles or plant material selected from seeds, husks, straw, shells of nuts or seeds or mixtures thereof, a glued board comprising one or more layers of textiles or textile fibers, a resin board comprising a resin matrix with dispersed fibers or particles selected from: particles of wood fibers, wood chips, wood strands, one or more layers of textiles, textile fibers, plant particles selected from seeds, husks, shells of nuts or seeds and mixtures thereof.

Description

BRIEF DESCRIPTION

[0095] Some of the embodiments will be described in detail, with references to the following Figures, wherein like designations denote like members, wherein:

[0096] FIG. 1 depicts a schematic representation of a LDF, MDF and HDF board production plant, including the following elements: [0097] 1. Wood logs [0098] 2. Debarker [0099] 3. Chipper [0100] 4. Chip hopper [0101] 5. Digester [0102] 6. Refiner [0103] 7. Resin+Additives [0104] 8. Blowline [0105] 9. Dryer [0106] 10. Cyclone [0107] 11. Fiber Conveyord [0108] 12. Mat formation and pre-press [0109] 13. Continuous hot press [0110] 14. Saw [0111] 15. Board Cooler [0112] 16. Sanding sizing and grading [0113] 17. Package [0114] a. Air or fuel gas [0115] b. Solid Material [0116] c. Steam;

[0117] FIG. 2 depicts a schematic representation of a Blowline including the following elements: [0118] 1. Resin+Additives (e.g. wax, dye, fire-retardant) [0119] 2. Inlet pipes to the blowline [0120] 3. Blowline; and

[0121] FIG. 3 depicts a schematic representation of a Pilot plant—Lab-scale equipment for wood composite board production including the following elements: [0122] 1. Hopper/Inlet wood fibers [0123] 2. Valve to insert wood fibers in the system [0124] 3. Industrial Ventilator [0125] 4. Spray [0126] 5. Loop pipe/Circulation of the fibers [0127] 6. Valve to outlet the fibers from the system [0128] 7. Collector/Container for Impregnated fibers.

DETAILED DESCRIPTION

[0129] Referring to FIGS. 1 and 2, Wood logs (FIG. 1-1) are debarked (FIG. 1-2) and then converted into chips mechanically (FIG. 1-3). The chips are then screw transported (via a chip hopper) (FIG. 1-4) into a digestion vessel (FIG. 1-5) and steamed for 30-120 seconds before being fed into a defibrator, which maintains a high pressure and temperature (typically around 8 bars, 180° C. while grinding the wood chips into a pulp. The pulp is released from refiner (FIG. 1-6) via a tube called the “blowline” into a drier (FIG. 1-8 and FIG. 2). Because of the pressure drop from circa 8 bars to atmospheric pressure on release into the blowline (FIG. 2-3), the pulp moves at high speed with very turbulent flow in the blowline, facilitating mixing of components. The blowline is a hence a key component of the fiber board line, and is fitted with a number of injection points/nozzles (FIG. 2-2) which can introduce additives, such as the fire retardant and liquid (water-based) resin binder into the turbulent mass of fibers ejected from the refiner.

[0130] The fire-retardant solution can be inserted as additive in two different ways, in solid and in liquid solution. For 100 kg solid fire-retardant composition, a mix of 15-20 Kg of MAP.

[0131] 75-80 kg of DAP, 5-10 kg organic acid, in particular citric acid or formic acid, 1-3 kg other additives such as sodium benzoate and/or sodium salicylate will be used. The production of liquid composition requires for 100 kg liquid composition 50 kg solid mix and 50 kg water, resulting in a 50 wt. % concentration.

[0132] From the blowline, the fibers enter an expansion chamber and then a flash drier (FIG. 1-9), in which the fiber mass and additives rapidly dry, wherein moisture content at drier exit is typically 8-12%. The dried mass enters a mat-former (FIG. 1-12), after which the mat is pre-compressed and either sent straight to a continuous hot press (FIG. 1-13) or cut into large sheets (FIG. 1-14) for a multi-opening hot press former. The resin binder is cured during hot-pressing, catalysed by the thermal activation of the latent acid hardener.

[0133] Referring to FIG. 3, Pilot system—laboratory-scale production of wood composite boards is shown.

[0134] For the production of laboratory-scale wood composite boards, a loop device is used as shown in FIG. 3.

[0135] In this process, the fibers are inserted into the system by the hopper (FIG. 3-1) and pass to the system through the inlet valve (FIG. 3-2). The wood fibers will move through the loop thanks to an industrial ventilator (FIG. 3-3), which will circulate the fibers through the loop pipes (FIG. 3-5) at the desired speed. During the circulation of the fibers in the system, the required and previously passed amount of resin and additives, such as fire retardant and/or dye, will be introduced through a spray (FIG. 3-4). When all the spray content is used, the fibers are completely impregnated. At this moment the outlet valve is opened (FIG. 3-6) and the fibers in circulation enter the fiber collector (FIG. 3-7). These fibers are ready for pressing in a standard laboratory press for the production of a wood composite board sample.

EXAMPLES

Example 1

[0136] Using a pilot system (as described above and shown at FIG. 3) for resinating and introducing additives to wood fibers suitable for pilot-scale production of MDF or HDF test boards, the following mix was prepared.

TABLE-US-00001 TABLE 1 Concentration Amount Material (%) (g) Wood Fibers — 560 Melamine Urea Formaldehyde 65 202 (MUF) Resin RED Color 11.5 50 Fire retardant blend “Burnblock” 40 101.7

[0137] The Fire-retardant blend “Burnblock” used contained the following: DAP: 25-35 wt. % MAP: 2-6 wt. %; Citric Acid: 4-6 wt. %, Sodium Benzoate: 0.5-1 wt. %; Water: 55-60 wt. %. MUF Resin: Water 34-37 wt. %; Melamine-Urea 63-65 wt. %; Formaldehyde <0.20 wt. %. No addition of any other latent hardener catalyst was made.

[0138] In the pilot system, blowline blending is simulated as the dry wood fibers are introduced into a steel tube loop and are blown around rapidly using an air flow (max 2.8 m.sup.3/h) generated by an industrial ventilator. The liquid additives are introduced via spray nozzles (atomized droplets) into the moving fiber, ensuring even distribution. After 10 minutes or so of circulation, the fiber mass is dry enough, and is discharged from the pilot loop, to enable formation of a fiber mattress ready for placing in a lab-scale hot press. The objective was to produce 8 mm thick test panels, with red color, of density close to 900 kg/m3. The hot-pressing was carried out using press-temperature of 160° C., for 5 minutes, ensuring a core temperature of at least 120° C. was achieved.

Mechanical Properties

[0139] Resulting panels had an average density of 991 kg/m.sup.3, were of good appearance, even red color and testing according to international standards gave the following results:

TABLE-US-00002 TABLE 2 Properties Thickness (mm) 7.63 0.04 (≈8) Density (kg/m.sup.3) 991 6.85 (>850 kg/m.sup.3) Bending Flexion (N/mm.sup.2) 53 4 (>34 N/mm.sup.2) Elasticity (N/mm.sup.2) 3563 276 (>3000 N/mm.sup.2) Internal bond Internal bond 1.44 0.3 (N/mm.sup.2) (>1.3 N/mm.sup.2)

[0140] Cone calorimeter testing (ISO 5660-1) on the pilot panels indicated a fire classification range for the test pieces of A2/B. Sample P12.

TABLE-US-00003 SBI Prediction Cone Calorimeter Tests Predicted Re- 2nd Heat Euroclass Predicted Predicted Sample Weight Ignition Flame- Flame Flux (Based on FIGRA TMR ID (g) (Spark) (kW/m2) start of test) (W/s) P22 N/A N/A A2/B P22 N/A N/A A2/B indicates data missing or illegible when filed

[0141] The cone calorimeter is a fire device based on the principle of oxygen consumption during combustion. It is considered the most significant bench scale instrument in fire testing. This apparatus has been adopted by the International Organization for Standardization (ISO 5660-1) for measuring heat release rate (HRR) of a sample.

[0142] A fuel sample surface can be radiated with different heat fluxes by this device. The fuel sample ignites and burns in excess air. HRR is based on the fact that the oxygen consumed during combustion is proportional to the heat released. This device analyses the combustion gases and measures the produced smoke from a test specimen that is being exposed to a certain heat flux. At least the oxygen concentration must be analyzed to calculate the released heat, but to improve the accuracy, carbon monoxide and carbon dioxide concentrations can also be analyzed. The data collected from this bench scale real fire test can be used for fire modelling, prediction of real scale fire behavior, pass/fail tests.

Example 2

[0143] Using a pilot system for resinating and introducing additives to wood fibers suitable for pilot-scale production of MDF or HDF test boards, the following mix was prepared.

TABLE-US-00004 TABLE 3 Material Concentration (%) Amount (g) Wood Fibers — 700 MUF Resin 65 252 BLACK Color 10.5 23 Burnblock 50 100.8

[0144] The Fire-retardant blend “Burnblock” used contained the following: DAP: 30-40 wt. %: MAP: 6-10 wt. %; Citric Acid: 4-6 wt. %; Water: 40-50 wt. %. No addition of any other latent hardener catalyst was made. MUF Resin: Water 34-37 wt. %; Melamine-Urea 63-65 wt. %; Formaldehyde <0.20 wt. %.

[0145] As described in example 1, a pilot steel loop was used for introduction of liquid components to the fibers. The protocol described therein was followed. The objective was to produce 8 mm thick test panels, with black color, of density close to 900 kg/m3. The hot-pressing was carried out using press-platten temperature of 160° C., for 5 minutes, ensuring a core temperature of at least 120° C. was achieved.

[0146] Mechanical Properties—main parameters and achieved properties are shown below

TABLE-US-00005 Properties Thickness (mm) 8.20 0.31 (≈8) Density (kg/m.sup.3) 940.0 19.3 (>850 kg/m.sup.3) Bending Flexion (N/mm.sup.2) 56 4 (>34 N/mm.sup.2) Elasticity (N/mm.sup.2) 4130 642 (>3000 N/mm.sup.2) Internal bond Internal bond 1.74 0.15 (N/mm.sup.2) (>1.3 N/mm.sup.2) Swelling Swelling (%) 10.7% 3.6% (<12%) Moisture Moisture (%) 6.1% 0.1% (4% to 11%)

[0147] The test panels had an average density of 940 kg/m3, were of even black color and met or exceeded all physical and mechanical property requirements needed for MDF.

[0148] Upon fire testing, the product achieved Euro-CLASSIFICATION: A2/B (Cone calorimeter test ISO 5660) Sample P22.

TABLE-US-00006 SBI Prediction Cone Calorimeter Tests Predicted Re- 2nd Heat Euroclass Predicted Predicted Sample Weight Ignition Flame- Flame Flux (Based on FIGRA TMR ID (g) (Spark) (kW/m2) start of test) (W/s) P22 N/A N/A A2/B P22 N/A N/A A2/B indicates data missing or illegible when filed

Example 3

[0149] Use of fire retardant formulation in a full-scale MDF testing using an industrial line as described on FIG. 1, incorporating a multi-injection point blowline for introduction of liquid resin and additives (FIG. 2).

[0150] The Burnblock fire retardant formulation used comprised the following: DAP: 30-40 wt. % MAP: 60-10 wt. %; Citric Acid: 4-6 wt. %; Water: 40-50 wt. %. MUF Resin: Water 34-37 wt. %; Melamine-Urea 63-65 wt. %; Formaldehyde <0.20 wt. %. No addition of any other latent hardener catalyst was made. The target was production of a black colored MDF panel of 19 mm thickness and density around 850 kg/m.sup.3

[0151] The operating conditions can be summarized as follows: [0152] 19 mm black MDF type panel [0153] PRODUCTION [0154] (m.sup.3/h): 5.38

TABLE-US-00007 Required Burnblock Burnblock Burnblock Burnblock Burnblock Flow Flow Flow Flow (1) Intake (kg/m.sup.3) (kg/h) (1/h) (1/min) 60 minutes 30 322.80 249.7 4.16 249.65

[0155] The flame-retardant (which also functioned as laten hardener) was added using the last 2 injection points on the blowline, with resin and dye being added at prior injection points.

TABLE-US-00008 Loading Loading Density of Resin of Dye Thickness Production of board (solid/dry (solid/dry (mm) (m.sup.3/h) (kg/m.sup.3) fiber) fiber) 19 5.38 820 30.3 2.36

[0156] Mechanical Properties—main parameters and achieved properties are shown below.

[0157] The panel was of even black color and had properties which passed all of the international mechanical property test criteria required for such products.

TABLE-US-00009 TABLE 4 Resume tests for 19 mm black Panels Parameters Average S.D. Properties Thickness (mm) (19 ± 0.2) 19.15 0.02 Density (kg/m.sup.3) (>820 kg/m.sup.3) 761.1 6.4 Bending Flexion (N/mm.sup.2) (>30 N/mm.sup.2) 51 2.6 Elasticity (N/mm.sup.2) (>2700 N/mm.sup.2) 4257 235 Internal bond Internal bond (N/mm.sup.2) 1.20 0.05 (>0.95 N/mm.sup.2) Swelling in thickness Swelling (%) (<8%) 5.75 0.29 Moisture Moisture (%) (4% to 11%) 6.1 0.1 Formaldehyde class E1 (≤8.0 mg/100 g oven dry board) Corrected to 6.5% moisture content 6.4 Durability - Internal bond (EN 321) Internal bond (N/mm.sup.2) 0.38 0.03 (>0.20 N/mm.sup.2) Durability - Swelling in thickness (EN 321) Swelling (%) (<15%) 6.12 0.20 Reaction to fire (EN 13501-1:2017)-CLASSIFICATION According to EN 13823 B-s1, d0

TABLE-US-00010 PARAMETER AVERAGE VALUE FIGRA 0.2 MJ (W/s) 87.03 FIGRA 0.4 MJ (W/s) 87.03 THR 600 s (MJ) 7.27 SMOGRA (m.sup.2/s.sup.2) 74.70 TSP 600 s (m.sup.2) 5.10 LFS (Y/N) No drops/particles flamed (Y/N) No TSP 600 s (m.sup.2) corrected 49.24 SMOGRA (m.sup.2/s.sup.2) corrected 3.67

[0158] The fire testing according to EN 13501-1:2007, shown above confirmed that the panel achieved Euro class B (B-s1, d0).

Fire Test According to EN13501-1:2007

[0159] One sample is tested, formed from two wings (short wing and long wing), 495 mm×1500 mm and 1000 mm×1500 mm and corresponding thickness, forming a corner where a fire is caused in standard conditions.

[0160] The specimens are conditioned to 23° C.+/−2° C. and a relative humidity of 50%+/−5%, according to the standard UNE-EN 13238:11, either by a fixed period of time, either to constant weight.

[0161] The tests are performed in the equipment called SBI (Single Burning Item), which consists of a test chamber, a test apparatus (sample holder cart, burner, frame, hood, collector, and ducting), and the smoke extraction system and team general measures.

[0162] The test principle is to have the two wings of the test material in a vertical position in right angle so that they are exposed to a burner located in the lower corner (main burner). The flames are obtained by combustion of propane gas, injected through a sand bed with an output power (30.7+/−2.0) kW.

[0163] The behavior of the sample is evaluated over a period of 20 minutes, determining performance parameters such as heat emission, smoke production, lateral spread of flame and drop inflamed particles.

[0164] A short time before the main burner ignition is used to quantify heat and smoke produced only by the burner, using an identical burner away from the sample and called auxiliary burner.

[0165] Measurements are taken either automatically or by visual observation. The extraction pipe is equipped with temperature sensors for measuring the attenuation of light, the molar fraction of oxygen and carbon dioxide, and the flow induced by the pressure difference in the canal. These amounts are recorded automatically and used to calculate the volume flow, the energy release (HRR) and smoke production rate (SPR).

[0166] The main visual observations are: lateral spread of flame and drops in flames.

[0167] So, as the test results are determined/calculated: [0168] FIGRA 0,4MJ (W/s): Maximum value of coefficient of heat release rate for the sample and □ the moment is started, using a threshold THR (amount of heat evolved) of 0.4 MJ. [0169] THR 600s (MJ): Total amount of heat released from the sample in the first 600 seconds of the start of exposure to the main burner. [0170] SMOGRA (m2/s2): Smoke production rate. Maximum value of the ratio of the speed of production of smoke by the sample and the time during which it is produced. [0171] TSP 600s (m2): Total production smoke of the sample in the first 600 seconds of the start of exposure of main burner flames. [0172] LSF edge: Lateral flame spread along the long wing of the sample. [0173] Droplets or flamed particles with inflammation times higher or lower than 10 seconds.

[0174] According to Table 1 in “Fire classification on construction products and building elements Part 1: Classification using test data from reaction to test fire tests”, EN 13501-1:2007.

TABLE-US-00011 Flaming droplets/ particles Main classification Smoke classification classification A2 FIGRA.sub.0.2 MJ ≤ 120 W/s s1 SMOGRA ≤ 30 d0 No flaming and LFS < specimen edge m.sup.2/s.sup.2 droplets/part. B THR   ≤ 7.5 MJ TSP   ≤ 50 m.sup.2 C FIGRA.sub.0.4 MJ ≤ 250 W/s s2 SMOGRA ≤ 180 d1 No flaming LFS < specimen edge m.sup.2/s.sup.2 droplets/part. THR   ≤ 15 MJ TSP   ≤ 200 m.sup.2 persisting > 10 s D FIGRA ≤ 750 W/s s3 — d2 — indicates data missing or illegible when filed

Example 4

Gel Time/Hardener Effect:

[0175] Gel time tests have been carried out for MUF resin using different hardener/fire retarder sample compositions according to embodiments of the present invention and reference hardeners.

[0176] Sample compositions were made by mixing the components mentioned in table 5 with water in the prescribed weight percentage:

TABLE-US-00012 TABLE 5 sample compositions of hardener/fireproofers used in gel time tests. Diammonium Monoammonium Citric Acid Water Exp. No. Phosphate (wt. %) Phosphate (wt. %) (wt. %) (wt. %) Sample 1 38.0 8.0 4.0 50.0 Sample 2 26.0 20.0 4.0 50.0 Sample 3 — 46.0 4.0 50.0 Sample 4 30.0 16.0 4.0 50.0

[0177] To perform the gel time tests, the Melamine Urea Formaldehyde (MUF) resin was mixed with different hardener/fire retarder compositions.

[0178] The mixing was performed under continuous agitation while heating the sample using a water bath at 100° C. The times for gelation have been measured and the results can be shown in the following table (table 6).

TABLE-US-00013 TABLE 6 gelation time for MUF using the hardener/fireproofing composition or reference hardeners or fireproofers. Total Amount Type of Amount of Volume of Exp. Resin hardener/fire hardener/ the sample Gel time Nr. MUF proofer fire proofer (g) (sec) 1 80% Sample 1 20% 50 >300 2 80% Sample 2 20% 50 ~270 3 80% Sample 3 20% 50 ~280 4 80% Sample 4 20% 50 ~300 5 80% Sample 1 20% 25 ~250 6 80% Sample 2 20% 25 210 7 80% Sample 3 20% 25 226 8 90% Sample 1 10% 25 220 9 90% Sample 2 10% 25 140 10 100%  — — 25 >86400 11 48 g/96% MAP 2 g/4% 50 80

CONCLUSIONS ON GELLING EXAMPLES

[0179] A decrease in the amount of water added during the gel-time process produces a considerable increase in the curing of the resin.

[0180] An increase in the amount of MAP in the sample increases the cure rate of the resin.

[0181] It has been proved that Sample 1, 2, 3 and 4 all have a hardener effect on the MUF resin.

[0182] Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0183] For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements. The mention of a “unit” or a “module” does not preclude the use of more than one unit or module.