JP2001139315A - Method for manufacturing ii type ammonium polyphosphate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily manufacture high-purity II type ammonium polyphosphate(APP) and to provide a method for manufacturing the fine II type APP. SOLUTION: This method comprises manufacturing the II type APP by heat treating an ammonium polyphosphate mixture composed of V type APP and the II type APP at 160 to 240 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a type II ammonium polyphosphate which is a material having flame retardancy.

[0002]

2. Description of the Related Art Ammonium polyphosphates (hereinafter, "ammonium polyphosphate" is abbreviated as "APP") are known from I-type to VI-type depending on the crystal structure. Among them, type I APP is obtained by mixing a phosphorus-containing compound such as ammonium phosphate with a condensing agent such as urea,
The composition can be relatively easily synthesized by heat treatment at a temperature of up to 300 ° C. However, since the I-type APP has a drawback of poor water resistance, it has been difficult to use it as a flame retardant to be blended with a resin.

[0003] On the other hand, type II APP is a material having relatively excellent water resistance, and can be used as a flame retardant.
Various methods have been proposed for the production of type II APP. For example, a method in which diphosphorus pentoxide and diammonium hydrogenphosphate are mixed in a substantially equal molar ratio, heated in the presence of ammonia, and heat-treated at 200 to 400 ° C. while mixing (Japanese Patent Publication No. 3-23,485) Publication), diphosphorus pentoxide and ammonium phosphate are mixed in a substantially equal molar ratio, and the reaction product is heat-treated while being constantly stirred.
A method of melting at a temperature of from 350 to 350 ° C., a step of adding moisture immediately before the melt solidifies under an ammonia atmosphere, and a step of adding ammonia at a temperature of from 200 to 320 ° C. in an ammonia atmosphere (Japanese Patent Application Laid-Open No. 12311) and the like. However, this method requires the use of a special reactor capable of mixing or kneading.

On the other hand, a type II AP which does not require the use of a special reactor capable of mixing or kneading.
As a method for producing P, a method has been proposed in which ammonium phosphate and urea are used as raw materials, and ammonia-containing wet air and dry air are alternately passed through to produce P (Japanese Patent Application Laid-Open No. 7-315817). In this method, control of the atmosphere in the apparatus is complicated, and complicated operations are required. Further, it is known that the type II APP is generated by a phase transition by heat-treating the type I APP at 250 to 270 ° C. in an ammonia atmosphere (Kjell R Wae).
rstad et al. Agric. Food Che
m. , 24, 412 (1976)), the rate of phase transition from type I APP to type II APP is very slow. For example, type II APP is completely type II even when heat-treated at 280 ° C for 3 hours in an ammonia atmosphere. APP did not form.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a high-purity II.
An object of the present invention is to provide a method for easily manufacturing a mold APP.
It is a further object of the present invention to provide a method for producing fine type II APP.

[0006]

Means for Solving the Problems The present inventors have intensively studied a synthesis method capable of easily producing a type II APP, and as a result, it has been found that 10 to 90% of a V type APP and a type II AP
An APP mixture containing 90 to 10% of P
By heat treatment at 0 ° C, high purity and fine type II APP
Was found to be able to be produced, and the present invention was completed.

Hereinafter, the present invention will be described in detail.

In the method for producing a type II APP of the present invention, an APP mixture used as a raw material (hereinafter sometimes abbreviated as “raw material”) is composed of a V type APP and a type II AP.
What consists of P is preferable. The content of V-type AP was determined based on the total amount of APP in the APP mixture.
The amount of P is 10 to 90%, and the amount of type II APP is 90 to 10%.
% Is preferable. The raw material does not substantially contain any other type of APP other than the V-type APP and the II-type APP. For example, I-type APP and VI-type APP
Is contained in a significant amount, it may be difficult to obtain type II APP.

In this specification, the type I APP, I type
I-type APP, V-type APP and VI-type APP are crystals whose general formula is represented by NH ₄ PO ₃ and whose X-ray diffraction patterns appear at the plane intervals shown in Tables 1, 2, 3 and 4, respectively. Compounds (Kjell R Waersta)
d et al. Agric. Food Chem. , 24,
412 (1976)). And, as shown in Tables 1 to 4, the amount of each APP means X of the APP composition.
Line diffraction was measured, and the strongest peak intensity of the type I APP having a plane spacing of 6.02 and the type II APP having a plane spacing of 5.70 were obtained.
V-type APP having the strongest peak intensity and interplanar spacing of 5.60
VI type AP having the strongest peak intensity and spacing of 6.62
Each of the strongest peak intensities with respect to the sum of the strongest peak intensities of P is expressed as a percentage.

[0010]

[Table 1]

[0011]

[Table 2]

[0012]

[Table 3]

[0013]

[Table 4]

The APP mixture used as a raw material in the method of the present invention includes II type APP and V type AP
P, and may consist essentially of these types of APPs. Depending on the production method, even if the type II APP and the V type APP are present as a composition, The APP of the type may be simply mixed, and the form of the APP is not limited.

The method for producing the raw materials is not particularly limited.
Hereinafter, preferred embodiments will be described.

The raw material is, for example, a mixture of a phosphorus-containing compound and urea in a molar ratio of 0.5 to 2.0 and an ammonia concentration of 10 to 2.0.
Heat treatment at a temperature of 350 to 380 ° C. in an atmosphere having a water vapor concentration of 20% by volume or less at a temperature of 350 to 380 ° C. to produce an intermediate, suspending the intermediate in water, and solid-liquid separation. It can be manufactured by drying at a temperature. The intermediate is
A composition comprising type II APP, type V APP, type VI APP, and the amount of each component is, for example, the amount of type II APP is 3 to 60%, the amount of type V APP is 25 to 90%, the type VI A
The amount of PP is about 1 to 25%. The intermediate does not substantially contain any other type of APP other than the type II APP, the V type APP and the VI type APP. For example, intermediate I
When a significant amount of PP is contained, type II APP and type V APP
It is difficult to obtain a raw material consisting of

The mixing molar ratio of the phosphorus-containing compound and urea is
The urea / phosphorus-containing compound is preferably in the range of 0.5 to 2.0, more preferably in the range of 0.8 to 1.6. When the mixture molar ratio of the phosphorus-containing compound and urea, that is, the ratio of urea / phosphorus-containing compound is less than 0.5, the sample may be melted. Increases, making it impractical.

As the phosphorus-containing compound, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, triammonium phosphate, diphosphorus pentoxide and the like may be used, and these may be used alone or in combination of two or more. You can also. Of these, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, and triammonium phosphate are preferably used, and diammonium hydrogen phosphate is more preferably used because of ease of handling.

In the heat treatment in the method of the present invention, the concentration of ammonia in the atmosphere is preferably in the range of 10 to 40% by volume, and more preferably in the range of 20 to 30% by volume. If the concentration of ammonia in the atmosphere is less than 10% by volume, the sample may be melted. If the concentration of ammonia in the atmosphere exceeds 40% by volume, I-type APP may be mixed.

The concentration of water vapor in the atmosphere is 20% by volume.
The following range is preferable, and the range of 1 to 10% by volume is more preferable. If there is no water vapor in the atmosphere, I-type AP
P and many VI-type APPs may be mixed.

As a method for adjusting the heat treatment atmosphere, a gas having an ammonia concentration and a water vapor concentration within the above ranges may be continuously supplied into the apparatus, and the space velocity may be about several to several hundreds per hour.

The temperature during the heat treatment is preferably in the range of 350 to 380 ° C. If the temperature during heat treatment is less than 350 ° C, I-type A
PP may be mixed in, and if it exceeds 380 ° C,
Some of the sample may melt. The time for the heat treatment is not particularly limited, but is preferably several to several tens of hours.

The intermediate obtained by the above method is suspended in a solution such as water. The solid content concentration of the intermediate in the suspension is not particularly limited, and may be about several to several tens weight%. The suspension time is not particularly limited, and may be about several minutes to several tens of hours.

Next, the suspension is solid-liquid separated and dried. The method of solid-liquid separation is not particularly limited, and examples thereof include a nutsche, a drum filter, a filter press, and a belt filter. The drying temperature is 50 ° C. or higher, preferably in the range of 60 ° C. to 110 ° C. The drying temperature is 50
If the drying temperature is lower than 110 ° C., the time required for completing the drying is longer than necessary, which is not preferable. If the drying temperature exceeds 110 ° C., it is not practical.

By this suspension, solid-liquid separation and drying treatment, an APP consisting essentially of a type II APP and a V type APP is produced, but although the detailed mechanism is unknown, the type II A
It is considered that APP of the type other than PP and V-type APP is substantially present in the liquid phase of the suspension, and that of II-type APP and V-type APP is substantially present in the solid phase. It is presumed that this can increase the ratio of type II APP and type V APP. However, such estimation does not restrict the present invention at all.

In this manner, a raw material of the type II APP is manufactured.

Next, a method for producing the type II APP of the present invention will be described.

The temperature of the heat treatment for producing the type II APP is preferably from 160 to 240 ° C., and more preferably from 160 to 220 ° C. in order to further reduce the average particle size of the finally obtained type II APP. Is in particular 180 to 2
A range of 00 ° C. is preferred. When the temperature of the heat treatment is lower than 160 ° C., the purity of the finally obtained type II APP may be reduced because V-type APP and VI-type APP are mixed,
On the other hand, when the temperature exceeds 240 ° C., the particles become too large or a high-temperature treatment is required.

The atmosphere in which the heat treatment is performed is not particularly limited. For example, the heat treatment can be performed in an atmosphere of dry air, air containing water vapor, or ammonia. Also,
The heat treatment time is not particularly limited, and may be several to several tens of hours.

In this way, a type II APP is manufactured.

Type II AP Obtained by the Method of the Invention
P can control the average particle size depending on the raw material used. For example, fine I with an average particle size of 5 μm or less
When an I-type APP is desired, it can be synthesized by using a raw material having an average particle size of 5 μm or less.
PP can be produced using the raw materials obtained by the method described in the preferred embodiment.

The type II APP of the present invention is a material having an excellent flame retardant effect, and is expected to be used as a flame retardant which is added to a resin to impart flame retardancy. When used as a flame retardant,
The APP composition of the present invention or the type II APP may be used alone, but may be used in combination with other flame retardants as needed. Other flame retardants include phosphorus-based flame retardants such as red phosphorus and phosphate esters; inorganic flame retardants such as magnesium hydroxide, aluminum hydroxide, zinc borate, and zirconium compounds; and 1,3,5-triazine derivatives. Nitrogen-containing compound, zinc ethylenediamine phosphate, antimony oxide, expandable graphite, etc., of which one or more of them can be used in combination.

[0033]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. The obtained APP composition of each type was determined by an X-ray diffraction method (XRD).
Method).

EXAMPLE 1 Diammonium hydrogen phosphate and urea were mixed at a molar ratio of 1: 1. The mixture was placed in an electric furnace having an internal volume of 2 liters, and the ammonia concentration was 30% by volume and the steam concentration was 2% by volume. Heat treatment was performed at 360 ° C. for 3 hours while introducing gas at a rate of 1 liter / minute, and the amount of type II APP was 23% and the amount of V type APP was 7
An intermediate was prepared with 3% and 4% amount of type VI APP.

Next, the intermediate was suspended in water so as to be 10% by weight and stirred at 30 ° C. for 16 hours. Thereafter, the suspension was solid-liquid separated by Nutsche and dried at 60 ° C. for 16 hours to produce a raw material. In the composition of the raw materials, the amount of type II APP was 37% and the amount of V type APP was 63%.

The raw material obtained by the above method was placed in an electric furnace having an internal volume of 2 liters, and heat-treated at 180 ° C. for 3 hours while introducing dry air at a rate of 1 liter / minute. The product was type II APP and the average particle size was 4.2 μm.
In addition, the average particle size is determined by LEDs & NORTHRUP CO
"MICROTRAC FRA9200" manufactured by MPANY
It is a value measured using.

Example 2 The raw material obtained in Example 1 was placed in an electric furnace having an internal volume of 2 liters, and dried air was introduced at a rate of 1 liter / min.
Heat treatment was performed at 3 ° C. for 3 hours. The product was type II APP, and the average particle size measured by the same method as in Example 1 was 3.
It was 7 μm.

Example 3 The intermediate obtained in Example 1 was suspended in water at 5% by weight and stirred at 25 ° C. for 30 minutes. Thereafter, the suspension was subjected to solid-liquid separation by Nutsche and dried at 110 ° C. for 16 hours to produce a raw material. The composition of the raw materials was such that the amount of type II APP was 90% and the amount of V type APP was 10%.

The raw material obtained by the above method was placed in an electric furnace having an internal volume of 2 liters, and heat-treated at 200 ° C. for 3 hours while introducing ammonia gas at 1 liter / minute. The product was type II APP, and the average particle size measured by the same method as in Example 1 was 4.9 μm.

Example 4 The raw material obtained in Example 3 was placed in an electric furnace having an internal volume of 2 liters, and heat-treated at 240 ° C. for 3 hours while introducing ammonia gas at 1 liter / minute. The product is type II A
PP, and the average particle diameter measured in the same manner as in Example 1 was 12.4 μm.

COMPARATIVE EXAMPLE 1 Diammonium hydrogen phosphate and urea were mixed at a molar ratio of 1: 1. The mixture was placed in an electric furnace having an internal volume of 2 liters, and ammonia gas was introduced at 220.degree.
Heat treatment was performed for an hour to produce an I-type APP.

The I-type APP obtained by the above-mentioned method was heat-treated in the same manner as in Example 3, but the product was
It was PP.

Comparative Example 2 An intermediate consisting of the type II APP, V type APP and VI type APP obtained in Example 1 was subjected to a heat treatment in the same manner as in Example 3, except that the product was II type APP, V-type APP, V
A mixture of type I APP, the amount of type II APP being 72
%, The amount of V-type APP is 24%, and the amount of VI-type APP is 4%
Met.

Comparative Example 3 The I-type APP obtained in Comparative Example 1 was placed in an electric furnace having an internal volume of 2 liters, and a gas having an ammonia concentration of 30% by volume and a steam concentration of 2% by volume was introduced at 1 liter / minute. While 36
Heat treatment at 0 ° C. for 3 hours, the amount of V-type APP is 80%, VI
An APP having a mold APP content of 20% was produced.

The APP obtained by the above-mentioned method is put into an electric furnace having an internal volume of 2 liters, and ammonia gas is supplied at a rate of 1 liter /
The heat treatment was performed at 220 ° C. for 3 hours while introducing the solution in minutes.
The product was a mixture of type II APP, type V APP, and type VI APP, the amount of type II APP was 51%, the amount of type V APP was 36%, and the amount of type VI APP was 13%.

Comparative Example 4 A heat treatment was performed in the same manner as in Example 3 except that the heat treatment temperature was changed to 140 ° C. The product is type II APP, type V AP
A mixture of P, 95% type II APP, V type A
The amount of PP was 5%.

From the above Examples and Comparative Examples, it was found that the type II AP
If the temperature of the heat treatment at the time of producing P is in the range of 160 to 240 ° C., and if the raw material composition at the time of producing II-type APP is substantially composed of II-type APP and V-type APP, It can be seen that the obtained type II APP has high purity.

Further, it can be seen that the particle size of the obtained type II APP can be reduced when the temperature of the heat treatment for producing the type II APP is relatively low.

[0049]

According to the method for producing a type II APP of the present invention, the following effects can be obtained.

1) This is a versatile production method that does not require the use of a special reaction device capable of mixing or kneading.

2) The obtained type II APP is substantially II
Only type APP is contained, and high-purity type II APP can be obtained.

3) The particle size can be controlled by controlling the particle size and reaction temperature of the raw material.

Claims (3)

[Claims] 1. A method for producing a type II ammonium polyphosphate, which comprises producing a mixture of ammonium polyphosphate consisting of ammonium type V polyphosphate and type II ammonium polyphosphate by heat treatment at 160 to 240 ° C. 2. The amount of ammonium V-polyphosphate is 10 to 90% and the amount of ammonium type II polyphosphate is 90 to 10% based on the total amount of ammonium polyphosphate in the ammonium polyphosphate mixture. The method for producing type II ammonium polyphosphate according to claim 1, wherein: 3. An ammonium polyphosphate mixture comprising 160 to
The method for producing a type II ammonium polyphosphate according to claim 1 or 2, wherein a heat treatment is performed at 220 ° C to produce a fine type II ammonium polyphosphate.