The method of producing flame retardant

 

(57) Abstract:

The invention relates to the technology of composite wood and cellulose materials. Describes a method of producing a flame retardant for drevesnoplitnye and cellulose materials by condensation in the melt phosphoric acid and urea, followed by cooling to a temperature of 60-70C and dissolved in water to a working concentration. While ammonium dihydrophosphate take in count of 36.3-and 39.7 wt.%, phosphoric acid in the amount of 20.6 48.4 wt.% and urea in the amount of 15.3-and 39.7 wt.%, add the Nickel catalyst in the amount of 0.2% to 0.5% by weight of the total dry matter and with stirring, heated to a temperature of 120-125C, maintain 15-25 min, cooled and diluted with water to a concentration of 30-60%. The technical result - improving process performance and product yield while ensuring variable acidity flame retardant. 3 table.

The invention relates to the technology of composite wood and cellulose materials. It is intended for the manufacture of materials with low Flammability.

As you know, among the fire-retardant means for drevesnoplitnye materials are the most effective phosphorus - and nitrogen-containing anti is it and plastics, manufactured by hot pressing. Their development is caused by the unsuitability of flame retardants that are designed for wood, due to the high temperatures of the pressing plates and a subsequent heat treatment. You want the acidity of the flame retardant meet the conditions of formation of the material was neutral in the finished product with the possibility of a sharp increase in fire conditions. The functional difference of flame retardants variable acidity is their active influence on inter-fiber interaction and participation in the process of structure formation drevesnoplitnye materials /Leonovich A. A. Variable acidity as a tool in the creation of fire protective composite materials // Chemistry of wood. - 1988 - N 5 - N-70-73/. The receipt of such flame retardants based on the interaction of phosphoric acid or ammonium phosphates with nitrogen-containing organic bases.

Flame retardant FMN (A. C. USSR N 195626) is obtained by neutralization of phosphoric acid, urea and dicyandiamide at a molar ratio of 1: 3: 1,5. The atomic ratio of nitrogen:phosphorus (N/P) is 12. The composition premiered synthesized in aqueous solution at a temperature of 85oC. depending on the duration of the I manufacture of fire protective solid fiberboard (MDF), including and.with. USSR N 268639. When the content in the fiber 28.8% of FMN with pH 4 DVP belong to the group of fire-resistant materials. Processing chip composition premiered at pH 4.0 to 4.5 with a flow rate of 15% on the dry substance allows to obtain particle Board (Spending) that are classified as fire-resistant (A. C. USSR N 346145). When processing paper premiered with a flow rate of 15% it made of decorative paper laminate (DBCP) is inflammable material (A. C. USSR N 352987).

The process of obtaining a composition premiered a long time and is from 2 to 3.5 hours by neutralizing to a pH above 5.2 homogeneity of the solution is disturbed as a result of coagulation due to a sharp decrease in solubility of the product /Leonovich A. A., Naughty, B. Fire protection of wood-based panels and laminates. - M.: Genre Differences. prom the terrain, 1974. - 128 S./.

Also known flame retardant /Pat. RF N 2055857/ produced by heating ammonium dihydrophosphate, or ammonium hydrogen phosphate, or mixtures thereof with urea at a mass ratio (1-2,3):1 in the presence of water at a temperature of 120oC followed by cooling and grinding. Flame retardant get directly in dry form. Deep impregnation of wood 20% solution of annuloaortic wood boards. The disadvantage of this flame retardant is its low solubility at about 25 g per 100 g of water. The possibility of using the composition in the manufacture of drevesnoplitnye materials by hot pressing the authors of the cited patent is claimed that, apparently, is connected with a strong hydration of wood particles due to the low solubility of the drug and the lack of regulation of its acidity.

As a prototype of the selected closest to the proposed invention is a method of obtaining a flame retardant KM /A. S. USSR N 517491/ intended to reduce the Flammability of composite wood and cellulose materials. Fire retardant KM are obtained by condensation of phosphoric acid and urea in the melt at a temperature of 132oC, then cooled and dissolved in water with the introduction of additional quantities of urea. Synthesis in the melt eliminates the initial hydrolysis of urea and the resulting flame at high temperature. The molar ratio of urea and phosphoric acid in the synthesis of KM (1.5 to 2.5): 1, which corresponds to an atomic ratio of N/P from 3 to 5. The degree of condensation of the flame retardant is characterized by acidity, determined by the conditions of manufacture konkretnej is otopleniya composite material with the use of urea binder necessary acidic or weakly acidic KM, when using phenolic resin requires a neutral flame. The duration of the synthesis of flame retardant KM depends on a given acidity and is 10-30 minutes, the total duration of the cycle the flame retardant 70-100 minutes fire Retardant KM has a high solubility in water (100-140 g per 100 g water) /Leonovich A. A. Theory and practice of the manufacture of fire protective wood boards. - L.: Publishing house of Leningrad. University, 1978. - 176 S./.

Fire retardant KM can be used in combination with ammonium chloride. When the mass ratio of KM: ammonium chloride and 10:1 is possible synergies phosphorus-halogen bonds, which increases the flame retardant efficiency of the flame retardant with respect to synthetic binder. Combustible solid fiberboard dry method can be obtained by treating the fibers with a flame retardant KM with N/P 5 and pH 5.5 with addition of ammonium chloride at a flow rate of 22.2% by weight of the fiber. The mass loss of the samples during the shooting test is 10-11% in the absence of self-combustion /Leonovich A. A. Fire protection of wood and wood-based materials: a manual. - SPb.: [- Pb LTA, 1994. - 148 C./.

Fire retardant KM is also used for fire-retardant treatment of paper. The estimated index flame spread M' according to the standard BS:I. Fire protective paper can be used for the manufacture of DBCP. Fire protection DBSP is provided with the content in the paper 10% flame retardant KM with N/P 3 and pH 6-7 by addition of ammonium chloride /A. S. USSR N 592594/. Currently, the use of chlorine - and sulfur-containing flame retardants begins to be limited due to environmental requirements.

The disadvantages of the method are associated with the complexity of the control synthesis process. The temperature of the condensation reaction of phosphoric acid and urea in the synthesis of flame retardant is 132 KMoC, but because ekzotermicheskogo heating the reaction mixture, the temperature rises and reaches 150oC. the Process is accompanied by foaming with a magnification of up to 1.5, which leads to the low fill factor of the reactor, of the order of 0.5 - 0.6 /Leonovich A. A. Fire protection of wood and wood-based materials. The tutorial. - Saint-Petersburg. [- Pb LTA, 1994. - 148/. This makes the process of obtaining a flame retardant KM swath.

It is also known that the solution of the flame retardant KM is free ammonia, which is not included in the product synthesis. Its share increases with increasing ratio N/P, as well as deepening the synthesis of flame retardant. This not only reduces their Spending (the temperature of 180-220oC) results in the release of ammonia. Thus, when heated to 50%-aqueous solution of the flame retardant KM with a ratio of N/P 3 at a temperature of 180oC for 8 min ammonia is released to 18.4 mg/g of dry flame retardant. Therefore, the presence of the flame retardant KM adversely affect the curing process of urea-formaldehyde oligomer and the quality of the plates. In addition, when opened, press the ammonia increases the pollution production facilities.

The aim of the present invention is to improve process performance and output anticorona while ensuring its variable acidity. This objective is achieved in that in the synthesis of flame retardant formed in the reaction mixture, the ammonia is again involved in the synthesis process. To obtain a flame retardant as initial components take the ammonium dihydrophosphate, phosphoric acid and urea and heat. In the synthesis of flame retardant additive is the reaction of interaction between ammonium dihydrophosphate and urea, which is carried out in the melt and in the presence of Nickel catalyst. A byproduct of this reaction is ammonium hydroxide NH4OH, which when heated gives ammonia. To interact with NH4OH the recipe impose phosphorous flame retardant can be represented by the following scheme:

< / BR>
Thus, the binding of the released ion NH4+phosphoric acid provides its use as a reagent for endogenous feeding components of the synthesis of additional quantity of phosphate of ammonia and more full course summary the condensation reaction.

By their chemical nature, the flame retardant can be classified as phosphoramidon /E.E. I. E. the Chemistry of organophosphorus compounds. - M.: Chemistry, 1971. - 352 S./. Such compounds have a high flame retardant efficiency due to the synergistic action of phosphorus and nitrogen /sultans MT, Sadykov, M. M. Muratov A. M, Cartagonova D. B. and other burning Inhibition of cellulose phosphate compounds 3. Povorotny synergism in the presence of the nitrile nitrogen Chemistry of wood. - 1986. - N 5. - S. 35-41./.

These provisions implement the following way. Synthesis of flame retardant is produced in the reactor with jacket, equipped with a stirrer, reflux condenser and thermometer. The fill factor of the reactor 0.7 - 0.8. The components of the synthesis is loaded into the reactor, add the Nickel catalyst and heated with continuous stirring to a temperature of 120-125oC. In the heating process at a temperature of 65-70oC starts the release of gaseous products are condensed and returned to the reaction mixture. At a temperature of 120-125oC runs the condensation reaction accompanied by foaming with a ratio of 1.2 and a thickening of the reaction mixture and the increase in pH. The duration of the synthesis is 15-25 minutes When the preset pH value of the product is cooled to a temperature of 60-70oC, add the calculated amount of water with a temperature of 60 5oC and stirred until complete dissolution.

Depending on the formulation of the flame retardant can be obtained when the ratio N/P of 1 to 3. In accordance with the purpose flame retardant synthesized with varying degrees of condensation of the starting components, the pH of the solution varies from 3.0 to 8.6. The acidity of the flame is determined by two factors - the ratio of N/P in its recipe and duration of condensation. The melting point of the dry flame retardant is 116-120oC, the solubility is from 40 to 150 g per 100 g of water, depending on the ratio N/P and the degree of condensation. The solution is colorless and is characterized by the density 1165-1315 kg/m3. If necessary, it can be diluted with water in any ratiooC. Warranty period is 1 year from date of manufacture.

Found the approach to the synthesis of flame retardant, which consists in linking ion NH4+and use it as a reagent, allows to minimize the subsequent allocation of ammonia when heated on stage hot pressing drevesnoplitnye materials. Thus, when heated this antipyrine with a ratio of N/P 3 at a temperature of 180oC for 8 min ammonia is released 2, 11 mg/g of dry flame retardant, which is 10 times less excretion of ammonia at the same time when termorasshirennyi flame retardant KM with the same ratio of N/P. This opens up the possibility of using the proposed flame retardant for the manufacture of fire-protected Spending on urea binder, reduce pollution and improve working conditions in the production area.

The temperature of the synthesis of this flame retardant in the 20-25oC lower than for flame AWAY. Foaming is reduced by 60%, which improves the fill factor of the reactor. Synthesis of flame retardant is carried out in the presence of a catalyst, which speeds up the process. In addition, the proposed method of producing flame retardant does not include the stage of adding an additional amount of urea after ohline obtain flame retardant is reduced by 20-40%. Thus, the method of obtaining the proposed flame retardant is more productive compared to flame AWAY.

Compared with the prototype fire-retardant efficiency of the flame retardant in the present method is higher due to the greater proportion of the phosphorus - base work item. Urea is introduced into the formulation in order to obtain a condensed product. At the same time, the urea is a combustible organic compound, and the increase above the norm reduces fire-retardant efficiency of a flame retardant. For flame retardant KM mass ratio of phosphoric acid and urea is (0.7-1,1): 1, and for the inventive flame retardant mass ratio of phosphorus-containing components and urea- (1,5-5,5):1.

The synthesis conditions and properties of the flame retardant according to examples 1 to 5 are given in table. 1.

Example 1 (the best)

In a reactor equipped with a jacket, stirrer, reflux condenser and thermometer, was loaded 38,0 wt. % dihydrofolate ammonium (GOST 3771-74), and 32.3 wt.% phosphoric acid (as used acid of 85% concentration according to GOST 6552-80, the flow rate was 38,0 wt.%) and 29.7 wt.% urea (GOST 6691-77). Added Nickel catalyst in an amount of 0.2 - 0.5% of the total dry weight. Vali to a temperature of 120-125oC and kept for 20 minutes Then the shirt was served water with a temperature of 10-20oC and cooled product to a temperature of 60-70oC. the Product was diluted with water based solution concentration of 63% and mixed (Re = 60000-80000) to dissolve the product. Water for dilution was taken with a temperature of 60 5oC. the resulting solution has a density 1315 kg/m3and a pH of 6.5. The atomic ratio of N/P for flame retardant according to this example is 2.

Example 2 (limit).

Obtaining a flame retardant was carried out according to the method of example 1, the proportion in the formulation of ammonium dihydrophosphate was 36,3 wt.% the proportion of phosphoric acid 48.4 wt. % (when using acid of 85% concentration - 56,9 wt.%), the proportion of urea and 15.3 wt.%. The duration of the synthesis at a temperature of 120-125oC was 15 minutes Adding water to the product carried out from the calculation of the concentration of a solution of 31%. The resulting solution has a density 1168 kg/m3and pH 3.0. The atomic ratio of N/P for flame retardant in this example is 1.

Example 3 (limit)

Obtaining a flame retardant was carried out according to the method of example 1, the proportion in the formulation of ammonium dihydrophosphate was $ 39.7 wt.%, the proportion of phosphoric acid of 20.6 wt. % (when using SUP>oC was 25 minutes, the Product was diluted with water based solution concentration of 52%. The resulting solution has a density 1211 kg/m3and pH of 8.6. The atomic ratio of N/P for flame retardant submitted example is 3.

Example 4 (the beyond)

Obtaining a flame retardant was carried out according to the method of example 1, the proportion in the formulation of ammonium dihydrophosphate comprised of 33.0 wt.%, the proportion of phosphoric acid - 61,9 wt. % (when using acid of 85% concentration was 72.8 wt.%), the proportion of urea - 5.1 wt.%. The atomic ratio of N/P for a recipe for this example is 0.5. In conditions of shortage of urea (N/P is less than 1) interaction does not occur. Adding water to the mixture were conducted from the calculation of the concentration of a solution of 46%. The resulting solution has a density of 263 kg/m3and pH of 1.6.

Example 5 (the beyond)

Obtaining a flame retardant was carried out according to the method of example 1, the proportion in the formulation of ammonium dihydrophosphate amounted to 42.0 wt.%, the proportion of phosphoric acid to 5.5 wt.% (when using the acid of 85% concentration of 6.5 wt.%), the proportion of urea - of 52.5 wt.%. The duration of the synthesis at a temperature of 120-125oC was 38 minutes Adding water to the product carried out from the calculation of the concentration of a solution of 43%. The resulting solution has Ocee amount of phosphoric acid causes a significant slowdown in the synthesis of flame retardant and decrease its solubility. An excess of urea in the formulation of the flame retardant reduces its fire-retardant efficiency.

In table. 2 shows data on the Flammability of paper, flame-retarded with different ratio of N/P (formulation and properties tab. 1) calculate the mass fraction of phosphorus in paper 2%. Samples of paper laminated to an inner layer of plastic mill (TU 13-7308001-766-88) impregnated with flame retardant solutions by immersion in the solution for 1 min, dried in air for 1 day and was tested for Flammability to BS: 476. This was determined by the self-combustion of the sample ( ), measured the length of the burned part of the sample (L) and calculated dimensionless evaluation index flame spread along the specimen (M'). The index M' characterizes the flame retardant efficiency of the flame retardant in the material. The maximum value of M' for hazardous under the terms of flame spread materials is 100.

The data presented show that for samples of paper containing the flame retardant with a ratio of N/P 1 to 3 in an amount of 2% of the phosphorus index M' is greater than 100. This indicates that the conditions ognezashita paper according to this test method for Flammability. Decrease of N/P to 0.5 prevailing. The increase of N/P to 5 also causes the decrease of the index M' due to excess nitrogen.

Thus, the paper handling flame retardant with a ratio of N/P 1 to 3 at a flow rate of 8-12% provides its translation into the category of materials that are not hazardous under the terms of flame spread. Indicators Flammability paper to BS: 476 show that fire-retardant efficiency of antipyrine by the present method is higher compared to the prototype.

In table. 3 illustrates the properties of superhard fire protective fiberboard (AGREED) dry production method of a thickness of 3 mm and a density of 960 10 kg/m3manufactured using flame retardant with different ratio of N/P (formulation and properties tab. 1). Consumption of flame retardant corresponded with the content in the plate 3% phosphorus. Mass fraction of paraffin was 1.5%. Plate extruded at a temperature of 200oC and a pressure of 5.5 MPa for 4.5 minutes Heat treatment of the plates was carried out at a temperature of 160oC within 30 minutes of Physical-mechanical testing of samples was performed according to AGREED GOST 19592-80. Water absorption and swelling of the samples AGREED that contains the flame retardant with the ratio N/P of 1 to 3, corresponds to the requirements of THE 13-444-83 on plate dry process production is em 60-70 MPa, which is higher than the standard rate by 20-40%. Weight loss of the samples AGREED when tested for combustibility does not exceed 20% for the duration of the self-combustion of less than 60 C. Thus, the introduction of fiber flame retardant with a ratio of N/P 1 to 3 in the amount of 3% of phosphorus provides the conditions ognezashita get plates.

The lower N/P to 0.5 accompanied by a decrease in the flame retardant nitrogen and a decrease in the proportion of the flame retardant in plates up to 10.5%. As a result, the Flammability of the samples increases above the permissible limit - time self-burning more than 60 C. Durability and waterproof performance of the samples AGREED deteriorate and do not meet regulatory requirements.

At N/P 5 is the reduction of physical and mechanical properties of the samples. A slight increase in mass loss AGREED when testing for combustibility due to excessive amounts of urea.

Thus, the use of flame retardant with a ratio of N/P 1 to 3 in the manufacture of AGREED ensures effective reduction in the Flammability of plates with a significant increase in their strength.

A method of producing a flame retardant for drevesnoplitnye and cellulose materials by condensation in the melt is her concentration, characterized in that the ammonium dihydrophosphate take in count of 36.3 - and 39.7 wt. per cent, of phosphoric acid in the amount of 20.6 48.4 wt.% and urea in the amount of 15.3 - and 39.7 wt.%, add the Nickel catalyst in the amount of 0.2% to 0.5% by weight of the total dry matter, with stirring, heated to a temperature of 120 - 125C, soak 15 to 25 min, cooled and diluted with water to a concentration of 30 to 60%.

 

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