WO2006109354A1

WO2006109354A1 - Process for simultaneously producing high-purity melamine pyrophosphate and melamine polyphosphate

Info

Publication number: WO2006109354A1
Application number: PCT/JP2005/006998
Authority: WO
Inventors: Naokazu Uiji; Makoto Watanabe
Original assignee: Shimonoseki Mitsui Chemicals, Inc.
Priority date: 2005-04-05
Filing date: 2005-04-05
Publication date: 2006-10-19

Abstract

A process for simultaneously producing high-purity melamine pyrophosphate and melamine polyphosphate, which comprises a step in which melamine and ammonium phosphate are pulverized and mixed to form a finely pulverized composition comprising melamine and ammonium phosphate and a step in which the finely pulverized composition is reacted with heating in the range of 190-350°C, wherein the finely pulverized composition is reacted with heating at 190-250°C to obtain melamine pyrophosphate and reacted with heating at 270-350°C to obtain melamine polyphosphate. These are suitable for use as a flame retardant for resins, etc.

Description

Method for co-production of high purity melamine pyrophosphate and melamine polyphosphate

The present invention relates to a production method capable of co-producing melamine pyrophosphate and melamine polyphosphate useful as flame retardants.

Background art

Melamine pyrophosphate and melamine polyphosphate are basically added to paints, synthetic resins, particle boards, etc., in which polyphosphoric acid (condensed phosphoric acid) and melamine are combined.

In the past, various production methods have been proposed that are useful as flame retardants that do not contain halogen such as chlorine.

(Conventional method for producing melamine pyrophosphate and melamine polyphosphate)

(A) One is a method in which melamine orthophosphate is used as a starting material, which is heated and calcined to condense to melamine polyphosphate.

For example, Japanese Patent Publication No. Sho 4 0-2 85 9 4 describes that melamine orthophosphate having a phosphorus content of 2 7-5 4% is heated and calcined at a temperature of 1800 to 2500 ° C, and at least one of them. It is disclosed that the melamine pyrophosphate is converted into melamine pyrophosphate. In particular, it is described that 40% or more of the melamine pyrophosphate is converted to melamine pyrophosphate by baking at 2 20-25.0 ° C. US Pat. No. 3,920,796 describes that a condensate composed mainly of melamine pyrophosphate can be produced by heating melamine orthophosphate at 1700-325 ° C. Further, it is disclosed together with the Arrhenius equation of the reaction rate of the condensation. Further, Japanese Patent Application Laid-Open No. 2 00 0-2 6 5 9 7 discloses polyphosphoric acid by heating melamine orthophosphate at 2600-320 ° C. It has been disclosed to produce melamine acid.

(B) Another method, in which the reaction of polyphosphoric acid and melamine, for example, Japanese閧昭6 1 - 1 2 6 0 9 The 1, P ₂ 0 ₅ concentration of 7 2 mass% or more polyphosphate and melamine Is allowed to undergo a solid phase reaction in the kneader at about 90-170 ° C in the substantial absence of an aqueous medium. The production of melamine polyphosphate

4, 950, 757 discloses the production of melamine pyrophosphate by reacting pyrophosphate and melamine in an aqueous solution at 0-60 ° C.

506063 discloses a method for producing melamine polyphosphate in which polyphosphoric acid obtained by contacting an alkali metal salt such as polyphosphoric acid with an acidic ion exchange resin is added to a melamine slurry and reacted.

(C) As another method, a method of directly reacting and condensing orthophosphoric acid and melamine to obtain melamine polyphosphate has been proposed.

For example, in JP-A-10-306081, an excess (2.0 to 4.0 mol) of melamine per 1 mol of orthophosphoric acid is mixed and reacted at a temperature of 0 to 300 ° C., and the reaction product is 340- It is described that a double salt of melamine / melam-melem polyphosphate can be produced by calcining at 450 ° C., and JP-A-10-81691 describes that 1.0 to 1.5 for one mole of orthophosphoric acid. It is disclosed that melamine polyphosphate is produced by calcining at 240-340 ° C a powdered product prepared by reacting 0,1—1.5 mol urea at 0_140 ° C. ing.

(D) As yet another method, JP-A-11-130413 discloses that melamine polyphosphate can be produced by firing a raw material composition of 1 mol of ammonium phosphate and 1.50 mol of melamine at 300-350 ° C. Is disclosed.

Japanese Patent No. 2004-155764 describes that melamine and ammonium phosphate are calcined at 170-230 ° C. to form melamine pyrophosphate, and Japanese Patent Application Laid-Open No. 2004-10649 discloses melamine, ammonium phosphate and urea. A mixture of 170-270. Calcination with C, then 270-350. The production of melamine polyphosphate by baking with C is described.

However, these conventional production methods are not sufficiently high in the decomposition temperature of the obtained melamine pyrophosphate and melamine polyphosphate, and have insufficient flame retardancy. Also, the loss of melamine during reaction or calcination is large, so it is necessary to use an excess of melamine relative to phosphoric acid, or to use polyphosphoric acid that is expensive and not easy to prepare as a starting material. There were some problems, and in order to obtain a sufficiently high purity, it was necessary to carry out a cleaning process with water substantially. All this way There was no way to be satisfied with this point. In the first place, a method for simultaneously producing melamine pyrophosphate and melamine polyphosphate has never been known.

This study is a method that can produce high-purity melamine pyrophosphate and melamine polyphosphate at an arbitrary ratio only by firing a mixture of raw material melamine and ammonium phosphate in a specific temperature range. Is intended to provide. Iffl disclosure

According to the present study, the following inventions are provided.

(1) A step of pulverizing and mixing melamine and ammonium phosphate to form a finely pulverized composition comprising melamine and ammonium phosphate, and a step of heating and reacting the finely pulverized composition within a range of 190-350 ° C. A method for co-production of high-purity melamine piprine phosphate and melamine polyphosphate, characterized by comprising:

(2) The finely pulverized composition is heated and reacted at 190-250 ° C to obtain melamine pyrophosphate, and is heated and reacted at 270-350 ° C to obtain melamine polyphosphate. Co-production method as described in 4.

(3) The method according to claim 1 or 2, wherein the melamine pyrophosphate and the melamine polyphosphate are obtained in a separated state or as a mixture.

(4) The co-production method according to any one of claims 1 to 3, wherein the composition of the phosphoric acid dimer in the melamine pyrophosphate calculated from the P-NMR peak area ratio exceeds 98%.

(5) The co-production method according to any one of claims 1 to 3, wherein the composition of the phosphoric acid multimer (n≥3) in the melamine polyphosphate calculated from the P-NMR peak area ratio is 97% or more.

(6) High-purity melamine pyrophosphate characterized in that the composition of phosphoric acid dimer in melamine pyrophosphate calculated by P-NMR peak area ratio exceeds 98%.

(7) A high purity melamine polyphosphate characterized in that the composition of phosphoric acid multimer (n 3) in melamine polyphosphate calculated by P-NMR peak area ratio is 97% or more.

(8) Melamine pyrophosphate obtained by the method according to any one of claims 1 to 5 And / or melamine polyphosphate, or melamine pyrophosphate and / or melamine polyphosphate according to claim 6 or 7, and polyethylene, polypropylene, polyvinyl acetate, ethylene vinyl acetate copolymer resin, polyamide, polyphenylene. Flame retardancy blended in at least one resin selected from diene ether, polyester, polycarbonate, polyalkylene terephthalate, polystyrene, polyurethane, ABS resin, epoxy resin, polyvinyl chloride, and these alloy resins Resin composition. Brief Description of Drawings

FIG. 1 is a flow chart showing a method for co-production of melamine pyrophosphate and melamine polyphosphate according to the present invention.

FIG. 2 is a graph showing an example of the firing temperature and the production state of melamine pyrophosphate and melamine polyphosphate when a finely pulverized composition of melamine and ammonium phosphate is heated and fired. Day 3 »Masame: To own

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. .

FIG. 1 is a flow sheet showing a method for co-production of melamine phosphate and melamine polyphosphate from melamine and ammonium phosphate as described above.

That is, the raw material compounds melamine 1 and ammonium phosphate 3 are sufficiently pulverized and mixed in the pulverization and mixing step 5 to form a finely pulverized composition 7 composed of melamine and ammonium phosphate. The finely pulverized composition has a temperature range (Ί \ —T ₂ ) that mainly produces melamine pyrophosphate in the temperature range of 190 to 350 ° C. in calcination step 9, melamine pyrophosphate and polyphosphoric acid. In the region where the mixture of melamine is formed (Τ ₃ — Τ ₄ ) and in the region where melamine polyphosphate is mainly produced (Τ ₅ -Τ ₆ ), the desired object is produced.

(Raw compound) (a) As one of the raw materials, melamine (C ₃ H ₆ N ₆ ) is preferably white crystal particles with high purity and no coloration, which may be either granular or powdery. Yes. If various impurities derived from the manufacturing process, such as melam, melem, ammelin, ammelide, melamine cyanurate, colored organic impurities, fine catalyst particles, etc. are contained, recrystallization, alkaline aqueous solution It is preferable to purify by a known means such as washing by filtration or filtration. In addition, commercially available products with high purity are available and can be suitably used.

(b) Ammonium phosphate includes 1 ammonium phosphate (NH ₄ H ₂ P0 ₄ ), 2 ammonium hydrogen phosphate ((NH ₄ ) ₂ HP0 ₄ ), 3 ammonium phosphate ((NH ₄ ) ₃ ) P0 ₄ In particular, it is preferable to use diammonium hydrogen phosphate in that: the highest yield can be obtained. A mixture of these three types of ammonium phosphate may be used.

As the ammonium phosphate, a white granular product or powdery product having a sufficiently high purity is preferable. In addition, when there are many impurities derived from wet phosphoric acid as a raw material, it is preferable to increase the purity by recrystallization, but it is also possible to use a commercially available high purity one as it is. '

In the present invention, first, as shown in the flow of FIG. 1, pulverization / mixing treatment with fine particles of melamine and ammonium phosphate as starting materials is performed, To do. This will be the raw material composition for firing in the next firing step. The next firing step 9 is a typical solid-phase reaction, and is estimated to proceed at the part (interface) where the particles of each component are in contact with each other. Therefore, in order to perform the solid-phase reaction homogeneously at a sufficient rate, the raw material composition is sufficiently finely divided into melamine and ammonium phosphate, and its surface area is increased. In addition, the component concentration distribution is statistically uniform to the extent that there is no bias in the composition, and accordingly, the contact area between the component particles is required to be as high as possible.

In this case, each of the raw materials may be mixed after being finely divided in advance, but it is preferable to include at least a step of performing both grinding and mixing. Accordingly, the apparatus for performing the pulverization and mixing step 5 may be a solid mixing apparatus, but more preferably a pulverizing / mixing apparatus capable of mixing while pulverizing. Here The “grinding / mixing process” basically includes an operation of pulverizing and mixing, an operation of mixing and then pulverizing, an operation of simultaneously performing pulverization and mixing, and further preliminary mixing, Further, it may be any operation for carrying out the pulverization and mixing at the same time. In short, any operation may be used as long as the operation can obtain the finely pulverized composition intended in the present invention.

For example, kneader mixer, roll mill, internal mixer, micro mixer, flash mixer, ribbon mixer, V-type mixer, ball mill, rod mill, hammer mill, attrition mill, non-mill mill A jet mill, a jet mizer, a micronizer, a microatomizer, a magic mill, a charlotte colloid dosole, a premier colloid mill, a micron mill, and a colloid mill can be suitably used.

Among these, particularly preferred are so-called ultra-fine grinding machines, jet mills, jet mizers, micronizers, microatomizers, magic mills, charlotte colloid domills, premier colloid dominoles, micron mills, and colloids. Grinding of domill, etc.

When preparing a small amount of the raw material composition, it may be performed in a mortar or a stone mortar. 'Normally, the average particle size (D 50) of melamine particles is about 20-100 zm, and that of ammonium phosphate particles is about 200-2000 zm. The average particle size (D 50) of ammonium phosphate is about 0.1-100 μm, preferably 1-50 / m, more preferably 1-20 μm, and most preferably about 1-10 μm.

In the present invention, the mixing ratio of melamine and ammonium phosphate is 0.8 to 1.5 mol of melamine, preferably 0.9 to 1.1 mol, more preferably 0.1 mol to 1.0 mol of ammonium phosphate. Melamine is 0.95—1.08 mole, most preferably 0.98—1.06 mole.

(Baking process)

In the method of the present invention, the finely pulverized composition thus adjusted is fired as a raw material for firing. In the firing step 9, melamine pyrophosphate is mainly produced in a temperature range of 190 to 350 ° C. Temperature range (T i— T ₂ ), Mera pyrophosphate In the region where the mixture of melamine and melamine polyphosphate is formed (τ ₃ — τ ₄ ) and the region where melamine polyphosphate is mainly formed (τ ₅ — τ ₆ ), firing is controlled accordingly. It has a feature in the point to be generated.

That is, as shown in Fig. 1, melamine pyrophosphate is obtained by firing in the temperature range (Ί \-Τ ₂ ), and melamine polyphosphate is obtained by firing in the region (Τ ₅ -Τ ₆ ). It is possible to produce a mixture in any proportion of melamine pyrophosphate and melamine polyphosphate by firing in the region (Τ ₃ – Τ ₄ ). Specifically, the temperature range (Ί — Τ ₂ ) is typically 190–2 50 ° C, and the range (T ₅ — T ₆ ) is 270–350 ° C, and the range (T ₃ — T _4). ) Is in the temperature range above 250 ° C and below 270 ° C.

Thus, by baking in the said temperature range, high purity melamine pyrophosphate (The composition of the phosphoric acid dimer in the melamine pyrophosphate calculated by P-NMR peak area ratio exceeds 98% is said. ), And high-purity melamine polyphosphate. The composition of phosphoric acid multimer (n 3) in melamine polyphosphate calculated by P-NMR peak area ratio is 97% or more. In addition, a mixture of these high-purity products is obtained.

Note that the mixture (composition) of melamine pyrophosphate and melamine polyphosphate was prepared by calcining melamine pyrophosphate and polyphosphate obtained by firing in the above temperature range (Ί \ —T ₂ ) and (Τ ₅ — Τ ₆ ), respectively. Needless to say, a composition of any ratio can be obtained by mixing melamine.

The firing time can vary depending on the raw material composition, the particle size of the raw material composition, the molar ratio, the raw material treatment amount, the firing temperature, the type of the firing apparatus for carrying out the firing, and is not particularly limited. One minute is 50 hours, preferably 30 minutes to 30 hours, more preferably about 40 minutes to 15 hours, and most preferably about 50 minutes to 12 hours. The firing step is performed by a dryer or a heating furnace that can heat the finely pulverized composition 7 as a firing raw material in the predetermined firing temperature region. These dryers or heating furnaces are not particularly limited as long as they can uniformly heat the raw material composition at a predetermined temperature and time. For example, a box-type dryer, a batch type or a continuous type rotation Furnace (Kuchiichi Tally Kiln), electric furnace, gas heating furnace, infrared heating furnace, moving bed furnace, fluidized bed furnace, etc. Preferably used. In addition, in the firing process, gas such as ammonia is released and released when the condensation reaction proceeds. For this reason, an inert gas such as nitrogen, an oxidizing gas such as dry air, and a reducing gas such as hydrogen are continuously fed into the furnace, and the firing process is performed. It is preferable that the entrainment is continuously removed from the system.

The melamine pyrophosphate or melamine polyphosphate obtained by the present invention is sufficiently high in purity as described above and can be preferably used as a flame retardant as it is. No purification process such as washing with water is required. However, if desired, operations such as washing with water, solid extraction (leaching), and repulping may be performed to obtain a product with higher purity.

(Combination of melamine pyrophosphate and melamine polyphosphate)

According to the method of the present invention, high-purity melamine pyrophosphate and melamine polyphosphate can be produced together in an arbitrary ratio. The significance of this is as follows. In general, melamine polyphosphate generally has favorable characteristics that, as the degree of condensation proceeds, the thermal decomposition temperature generally increases and the solubility in water decreases. On the other hand, as the degree of condensation increases, the acidity increases and the hygroscopicity increases. As a result, when blended with various resins, the affinity with the matrix resin due to moisture absorption, the occurrence of bleed, and the decrease in electrical insulation can occur.

Therefore, melamine pyrophosphate and melamine polyphosphate having a higher degree of polymerization are mainly used for applications where high thermal decomposition temperature and low solubility are more important depending on the purpose, and moisture absorption. It is preferable to mainly use melamine pyrophosphate for applications where safety, low bleeding, and low electrical insulation are more important. Furthermore, by using melamine pyrophosphate and melamine polyphosphate as a composition and adjusting the composition ratio as appropriate, it can be said that optimum performance is developed for each application. According to the present invention, melamine pyrophosphate, melamine polyphosphate, and an arbitrary composition thereof can be co-produced at an arbitrary ratio, so that the industrial significance is extremely large.

(P-NMR method) Melamine pyrophosphate and melamine polyphosphate obtained by the method of the present invention are extremely high in purity, particularly highly soluble in water, and bleed can be effectively treated with melamine orthophosphate which causes a decrease in insulation. Does not contain.

In the present invention, the purity of melamine pyrophosphate and melamine polyphosphate is

According to the P—N M R method. As a purity measurement method by this method, it is superior to the conventional method in the following points. That is,

Conventional methods for quantifying the purity of melamine phosphate, melamine pyrophosphate, and melamine polyphosphate include XRD (X-ray diffraction analysis), LC, and liquid chromatography. However, in XRD, although melamine orthophosphate and melamine pyrophosphate are registered in the ICPD card or JCPDS card, there is no registration for melamine polyphosphate. Therefore, the purity of polyphosphate could only be estimated based on the XRD beak of melamine polyphosphate synthesized by the self. In addition, although XRD analysis itself is frequently used for qualitative analysis, it is not necessarily reliable for quantitative analysis.

On the other hand, LC has a relatively high solubility in water for melamine orthophosphate, and it can be dissolved in water and measured for its concentration. However, melamine pyrophosphate and melamine polyphosphate are essential for water. The solubility of was extremely low, and accurate purity analysis using LC was difficult. In addition, since there is no suitable solvent for dissolving melamine orthophosphate, melamine pyrophosphate, and melamine polyphosphate without decomposing them, purity analysis using a solvent other than water was impossible.

In contrast, P-NMR is an analysis method that focuses on the P-terminal group and P-intermediate group of melamine orthophosphate, melamine pyrophosphate, and melamine polyphosphate, so there are no problems such as XRD and LC described above. Melamine orthophosphate, melamine pyrophosphate and melamine polyphosphate can each be accurately quantified. Thus, the P-NMR method employed in the present invention is an epoch-making that has made it possible to quantitate condensed phosphates that were previously impossible with conventional methods such as XRD and LC. This is a method.

(Flame retardant resin composition) Melamine pyrophosphate and / or melamine polyphosphate obtained by the method of the present invention can be blended with various polymer materials and resins to form a flame retardant resin composition. Examples of such resins include polyethylene, polypropylene, polybutene, polybutadiene, polyvinyl acetate, ethylene vinyl acetate copolymer resin, ethylene vinyl alcohol copolymer resin, polyamide, polyamide imide, polyether imide, and polyphenylene. Diene ether, Polyester, Polycarbonate, Polyethylene terephthalate, Polybutylene terephthalate, Polyalkylene terephthalate, Polyetheretherketone, Polyestersulfone, Polystyrene, Polymethylstyrene, Polyvinylphenol, Silicone Resin, Polyurethane, Polyacryloetryl, Polyvinyl butyral, ABS resin, ABS / PVC alloy, AAS resin, Methyl chloride resin, Norbornene resin, Epoxy resin, Polyethylene resin Vinyl chloride, Porishio fluoride, and the like these Aroi resins are exemplified as preferred. From these flame retardant resin compositions, resin molded products, coating materials, textile products, and the like imparted with high flame resistance can be obtained.

你 .I

Hereinafter, specific embodiments of the present invention will be described by way of examples. Hereinafter, unless otherwise specified,% indicates mass%.

Example 1

(1) Melamine (Mitsui Chemicals) 8.4 3 6 kg and hydrogen phosphate diammonium (Shimonoseki Mitsui Chemicals) 8.5 6 4 kg total 17 kg, Henschel mixer (FM-75, Mitsui Mine) And stirred at 1 3 2 O rpm for 2 minutes to obtain a premixed mixture.

The mixture was supplied to a jet mill (manufactured by Seishin Enterprise Co., Ltd., STJ-200) and pulverized and mixed. The particle size distribution of the pulverized mixture was measured by a laser diffraction scattering method (ICROTRACs MODEL No. 9320 X-100, manufactured by REEDS & NORTHRUP). The result is D50:

5 / m, Dio: 3 mm, D90: 8 mm. In addition, the mixed pulverized product has a melamine / ammonium phosphate molar ratio of 1.03, and the charging ratio is maintained. It was confirmed that

(2) 1700 g of the mixed 'ground product (hereinafter referred to as “raw material finely pulverized composition” or simply “finely pulverized composition”) contained in a stainless steel vat containing the finely pulverized composition. The bat was set in a box dryer (hot air type) (manufactured by Tabai).

Under nitrogen flow, as shown in Table 1, the temperature was raised to each predetermined baking temperature of 180-350 ° C in 120 minutes, and maintained at the predetermined temperature for 11 hours, respectively. The gas generated during firing was absorbed and collected by the phosphoric acid solution. Thereafter, the sample was cooled to 50 ° C. or lower under nitrogen flow, and calcined samples were fired at predetermined temperatures. The firing temperature is the temperature of the “finely pulverized composition” housed in the vat, and was measured by inserting thermocouple thermometers at six locations in the finely pulverized composition.

(3) The baked product (hereinafter also referred to as “baked product”) is crushed by stirring for 1 minute at 100 Orpm with a Henshi X-L mixer (made by Kokusan Centrifuge Co., Ltd., chemical mixer, capacity 20L). solid-state nuclear magnetic resonance analysis ⁽³¹ P MAS NMR spectroscopy equipment (manufactured by JEOL Ltd., the ECA400 used), P- beak area ratio or these NMR, Oruzorin melamine, melamine pyrophosphate, the composition ratio of the melamine polyphosphate ( OrthoZPyro / Poly) The results are shown in Table 1.

(Note) * Y = (Mass of fired product / Amount of finely pulverized composition) X I 00

**) Measured as 10% dispersion.

***) Average particle size is the value of D50. As shown in Table 1, in the present invention, it is understood that melamine pyrophosphate having a purity exceeding 98.0% is obtained at a calcination temperature of 190 to 250 ° C. The fired product easily became particles with an average particle diameter of 8 mm by simple crushing treatment. In addition, high-purity melamine polyphosphate with a purity of 97.0% or higher is obtained at a firing temperature of 270-350 ° C. Similarly, when fired at this temperature, the fired product can be easily crushed by a simple crushing treatment. And particles having an average particle size of 8 ^ m.

(Example 2) (1) 1700 g of the finely pulverized raw material composition for firing prepared in the same manner as in Example 1 was divided into three equal parts, and each was placed in a stainless steel bat. Each of them was referred to as “bat ① ヽ bat ② and bat ③”) in the same box-type dryer (manufactured by Yubai Co., Ltd.) as in the example, and heated and baked.

(2) FIG. 2 is a graph showing an example of the transition of the firing temperature and the state of production of melamine pyrophosphate and melamine polyphosphate when heated and fired under nitrogen flow.

First, the temperature inside the dryer (T a) (set temperature) 260 – 270 ° C was raised in 120 minutes, and after the temperature rise, the temperature of the finely pulverized composition (Ts) (hereinafter also referred to as “product temperature”) When the temperature reached 220 ° C (2 hours 30 minutes), the bat ① was removed.

(3) In the figure, A is the part where the product temperature (T s) curve becomes almost constant, which corresponds to the point where diammonium hydrogen phosphate releases ammonia and changes to phosphate-ammonium. It is estimated to be. In addition, it is estimated that part B where the product temperature curve becomes slightly constant from around 200 ° C is the part where melamine orthophosphate is changed to melamine pyrophosphate. The above vat (1) is taken out when the firing temperature rises again from B, that is, when it is estimated that the reaction of melamine orthozolate to melamin pyrophosphate has been completed. '?

(4) After this, the calcined product temperature (Ts) rises as shown in C, but when the temperature reaches a peak (D) and begins to fall slowly (product temperature: 250 ° C) (3 hours After 30 minutes), the bat ② was removed. The curve (E) after this point is the region where the formation reaction from melamine pyrophosphate to melamine polyphosphate is performed. In this region, as shown in Table 2 below, melamine pyrophosphate and melamine polyphosphate A mixture (composition) is obtained.

(5) Finally, when the product temperature reached 267 ° C and became almost constant (F) (1 1 hour passed), bat ③ was taken out. Each vat was cooled to 50 ° C. or lower under nitrogen flow as in Example 1, and the gas generated during firing was absorbed and collected in the phosphoric acid solution.

The obtained calcined product was crushed by stirring for 1 minute at 1 OOrpm using a Henschel mixer (Chemical mixer, volume 20 L, manufactured by Kokusan Centrifuge Co., Ltd.) in the same manner as in Example 1. By measurement (manufactured by JEOL Ltd., using ECA400), P—N The peak area ratio of MR was measured. The composition of the fired product (P-NMR peak area ratio) is shown in Table 2.

Table 2

As shown in Table 2, according to the present invention, high-purity pyrophosphoric acid is obtained by firing a raw material finely pulverized composition for firing and taking out a part of the ground composition at a predetermined firing temperature. Melamine (bat (1)), melamine polyphosphate (bat (3)), and a mixture of these (bat (2)) can be produced at the desired ratio.

Example 3

(1) 1700 g of the raw material pulverized composition for calcination prepared in the same manner as in Example 1 was divided into a ratio of 10 to 90, and ① 170 g and ② 15 30 g were accommodated in stainless steel bats The “bat (1) (170 g)” and the “bat (2 (1 530 g) j”) were set in the same box-type dryer (manufactured by Yubai Co., Ltd.) as in the example, and heated and fired.

First, the temperature inside the dryer (set temperature) 260-270 C is raised in 120 minutes. After the temperature rises, the vat ① is removed when the product temperature reaches 220 ° C (2 hours 30 minutes have passed). Baking continued.

When the product temperature reached 267 ° C and became almost constant (11 hours have passed), Bat 2 was taken out. Each vat was cooled to 50 ° C. or lower under nitrogen flow in the same manner as in Example 1, and the gas generated at the time of firing was absorbed into the phosphoric acid solution and recovered. The resulting fired product “Vat ① (1700 g) and Bag ② (1 5 30 g)” was mixed and dissolved with a Henschel mixer in the same manner as in Example 1, and the peak of P—N MR was obtained. The area ratio was measured. Table 3 shows the composition (P-NMR beak area ratio) of the fired product.

The same operation was performed by dividing the raw material pulverized composition for baking 1 700 g in a ratio of 50 to 50 (“Bat ① (8 500 g)” and “But ② (8 500 g)) ), Divided by a ratio of 80 to 20 (referred to as “bat ① (1 3 60 g)” and “bat ② (3 4 0 g) j”). It was set in a dryer (manufactured by Yubai Co., Ltd.), heated and calcined, and barts (1) were each taken out at 220 ° C, and barts (2) were taken out at 26 ° C each. Table 3 shows the results of mixing the product and the fired product of bat ② and measuring the composition (P-NMR peak area ratio).

From the results of Example 2, it was found that high purity melamine pyrophosphate and melamine polyphosphate were produced in the vat ① fired at 220 ° C. and the battery ② fired at 2 67 ° C., respectively. Obviously, as shown in Table 3, the ratio of each generation can be changed freely, such as 1 0 to 9 0, 5 0 to 5 0, 8 0 to 2 0, and finally mixed uniformly. Thus, a high purity melamine pyrophosphate and melamine polyphosphate mixed at an arbitrary ratio can be obtained. This is also an embodiment of the method of co-production of melamine pyrophosphate and melamine polyphosphate in the present invention. IlfflW Noh in Tsurugi ''

According to the present invention, high-purity melamine piprine phosphate and melamine polyphosphate can be co-produced at an arbitrary ratio by firing at the specific firing temperature using the same finely pulverized composition as a firing raw material. It is possible.

In addition, melamine pyrophosphate and melamine polyphosphate obtained by the method of the present invention are extremely high in purity, such as polyethylene, polypropylene, polyvinyl acetate, ethylene vinyl acetate copolymer resin, polyamide, and polyphenylene ether. It is preferably used as a flame retardant for polyester, polycarbonate, polyalkylene terephthalate, polystyrene, polyurethane, ABS resin, epoxy resin, polyvinyl chloride, and these alloy resins.

Claims

The scope of the claims

1. From the step of pulverizing and mixing melamine and ammonium phosphate to form a finely pulverized composition comprising melamine and ammonium phosphate, and the step of heating and reacting the finely pulverized composition in the range of 190-350 ° C. A method of co-production of high-purity melamine biphosphate phosphate and melamine polyphosphate, characterized in that

2. 1 90-250 for the finely divided composition. The co-production method according to claim 1, wherein melamine pyrophosphate is obtained by heating and reacting with C, and melamine pyrophosphate is obtained by heating and reacting at 270 to 3500C.

3. The co-production method according to claim 1 or 2, wherein the melamine pyrophosphate and the melamine polyphosphate are obtained separately or as a mixture.

4. The method of co-production according to any one of claims 1 to 3, wherein the yarn S formation of the phosphoric acid dimer in bimel phosphate melamine calculated by P-NMR peak area ratio exceeds 98%.

5. The co-production method according to any one of claims 1 to 3, wherein the composition of the phosphoric acid multimer (n ^ 3) in the melamine polyphosphate calculated from the P-NMR peak area ratio is 97% or more.

6. High-purity melamine pyrophosphate characterized in that the composition of phosphoric acid dimer in melamine pyrophosphate calculated by P-NMR peak area ratio exceeds 98%.

7. A high-purity melamine polyphosphate characterized in that the composition of phosphoric acid multimers (n≥3) in the melamine polyphosphate calculated by P—NMR peak area ratio is 97% or more.

8. Melamine pyrophosphate and / or melamine polyphosphate obtained by the method according to any one of claims 1 to 5, or melamine pyrophosphate and Z or melamine polyphosphate according to claim 6 or 7. Polyethylene, Polypropylene, Polyvinyl acetate, Ethylene vinyl acetate copolymer resin, Polyamide, Polyphenylene ether, Polyester, Polystrength Ponate, Polyalkylene terephthalate, Polystyrene, Polyurethane, ABS resin, Epoxy resin, A flame retardant resin composition obtained by combining at least one resin selected from polyvinyl chloride and these alloy resins.