JP3250019B2 - Method for producing granular ammonium polyphosphate crystals - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel granular crystal of ammonium polyphosphate, a method for producing the same, and a novel resin composition having excellent flame retardancy and bleed resistance containing the same. is there.

[0002]

2. Description of the Related Art Conventionally, ammonium polyphosphate is a well-known substance, and has been produced by a method of dehydrating and condensing ammonium orthophosphate, a method of mixing polyphosphoric acid with ammonia or urea and heating. Was.

JP-B-43-19218 discloses that a small amount of a water-insoluble ammonium polyphosphate is added to a composition comprising a phosphate, an ammoniating agent and a condensing agent.
A method for producing a water-insoluble ammonium polyphosphate characterized by heating to 100 to 350 ° C is disclosed. Japanese Patent Publication No. 47-38319 discloses a mixture of ammonium orthophosphate and urea having a boiling point of 190 to 300.
A method is disclosed in which, after reacting in a hydrocarbon medium at ℃, the reaction product is separated and heated at a temperature not lower than the boiling point of the hydrocarbon to remove the hydrocarbon. Furthermore, Japanese Patent Publication No. 60-6
No. 885 discloses that a small amount of melamine is added to a mixture of ammonium orthophosphate and diphosphorus pentoxide, and the mixture is reacted at 50 to 150 ° C. in the presence of excess ammonia.
A method for producing a long-chain ammonium polyphosphate characterized by performing a tempering treatment at 00 to 300 ° C. is disclosed. Reacting the mixture at 150-280 ° C. for 20-30 minutes with high mixing intensity in the crushed state,
Then, a method for producing a water-insoluble chain-like ammonium polyphosphate, which is characterized by subjecting to a heat treatment in an ammonia atmosphere at 250 to 280 ° C. for 100 to 120 minutes, is disclosed.

On the other hand, various inventions have been made on flame-retardant resins. For example, JP-A-61-66736 discloses that a polyolefin polymer is blended with a fibrous substance containing alkaline earth metal hydroxide, aluminum hydroxide, and silica. JP-A-61-213234 discloses a flame-retardant resin composition comprising a mixture of an olefin resin, an aluminum hydroxide and a magnesium hydroxide, and red phosphorus, zinc borate, and titanium dioxide. A flame-retardant resin composition characterized by the addition of is disclosed. Further, JP-A-3-5654
No. 7 discloses a flame-retardant resin composition characterized by adding ammonium polyphosphate to a polypropylene resin.

[0005]

The ammonium polyphosphates obtained by the above-mentioned methods are all amorphous coherent crystals, which need to be pulverized depending on the case, and have poor fluidity as powder. Dispersibility was not always sufficient. The problem to be solved by the present invention is to propose fine crystals of ammonium polyphosphate having excellent fluidity and dispersibility, establish a production method thereof, and provide a novel resin using the fine crystals. Is to do.

[0006]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have proposed diphosphorus pentoxide, a condensing agent such as urea and melamine, ammonium phosphate, ammonium carbonate,
An ammoniating agent such as ammonium bicarbonate is added to phosphorus 1
Nitrogen at a ratio of 1.2 mol or more to the
A particulate ammonium polyphosphate characterized by repeating a solid phase reaction step of heating to 0 to 320 ° C. in dry air and a sintering step of performing in a mixed atmosphere of ammonia and water vapor for 5 to 12 times. A method for producing crystals is proposed.

[0007] In the method for producing a granular ammonium polyphosphate crystal according to the present invention, an object is to provide a method for producing a granular ammonium polyphosphate crystal having an average diameter of 10 µm distributed in the range of 3 to 15 µm.
The following is a rice grain-like crystal having a smooth surface.

In the method for producing granular ammonium polyphosphate crystals according to the present invention, diphosphorus pentoxide forms the skeleton of ammonium polyphosphate, and the condensing agent is mainly diphosphorus pentoxide to polyphosphorus. Urea, melamine, etc. are used to condense to the acid skeleton.Ammonating agents are those that replace hydrogen ions of polyphosphoric acid with ammonia groups, ammonium phosphate, ammonium carbonate,
An ammonium salt such as ammonium bicarbonate is used.
In addition, in order to obtain rice-grain crystals having a smooth surface, the solid phase reaction step performed in dry air and the firing step performed in an atmosphere containing ammonia and water vapor are not performed only once, but are performed in 5 to 12 times. It is necessary to repeat it several times.

As the resin used in the resin composition containing ammonium polyphosphate in the form of granular crystals according to the present invention, polyolefin resins such as polyethylene, polypropylene and polystyrene, ethylene-propylene rubber, ethylene-propylene-butadiene Rubber, styrene-butadiene rubber, isobutylene-isoprene rubber, acrylonitrile-butadiene rubber, ethylene-ethyl acrylate resin, ethylene-vinyl acetate resin, and the like.

[0010]

In the method for producing ammonium polyphosphate according to the present invention, it is unclear what effect the granular crystals will be produced by, but it is considered that the following effects are involved. That is, in the solid-phase reaction performed in dry air, the condensation of diphosphorus pentoxide with a condensing agent is mainly performed, and ammonia and water are eliminated at the condensation site to form aggregated ammonium polyphosphate once. However, shortly thereafter, due to thermal decomposition, ammonia groups other than the condensation site are also eliminated and replaced with hydrogen ions, and the surface is smoothened by melting, and then, in firing performed in a steam mixed atmosphere, hydrogen ions are mainly removed. It is considered that granular crystals having a smooth surface are generated by the replacement with the ammonia group and the recrystallization.

[0011]

【Example】

1. Example 1 Production of Granular Crystals of Ammonium Polyphosphate Example 1 58 g of diphosphorus pentoxide, 26 g of urea, 39 g of ammonium bicarbonate, and 7 g of diammonium hydrogenphosphate were mixed and stirred in an electric furnace heated to 280 ° C. ,
A solid phase reaction step of flowing dry air at a flow rate of 42 l / hr for 20 minutes, followed by 3% ammonia and 4 mg of steam
The powder (hereinafter, referred to as “powder 1”) was obtained by alternately repeating the baking step in which air containing / l was flown at a flow rate of 42 l / hr for 20 minutes for 10 minutes.

Example 2 58 g of diphosphorus pentoxide, urea 2
6 g, 39 g of ammonium bicarbonate and 7 g of diammonium hydrogen phosphate are mixed, and while stirring in an electric furnace heated to 300 ° C., dry air is flowed at a flow rate of 72 l / hr for 20 minutes, followed by a solid phase reaction step. And 3% ammonia,
A baking step of flowing air containing 4 mg / l of steam at a flow rate of 72 l / hr for 20 minutes was alternately repeated 10 times to obtain a powder (hereinafter referred to as "powder 2").

[Example 3] 58 g of diphosphorus pentoxide, urea 2
6 g, 39 g of ammonium bicarbonate and 7 g of diammonium hydrogen phosphate were mixed, and a solid phase reaction was performed by flowing dry air at a flow rate of 72 l / hr for 120 minutes while stirring in an electric furnace heated to 280 ° C. After that, dry air
A solid phase reaction step of flowing at a flow rate of 2 l / hr for 20 minutes, followed by a firing step of flowing air containing 3% of ammonia and 4 mg / l of steam at a flow rate of 72 l / hr for 20 minutes,
The powder was alternately repeated six times to obtain a powder (hereinafter referred to as “powder 3”).

Example 4 58 g of diphosphorus pentoxide, urea 2
6 g, 39 g of ammonium bicarbonate and 7 g of diammonium hydrogen phosphate were mixed, and a solid phase reaction was carried out by flowing dry air at a flow rate of 42 l / hr for 120 minutes while stirring in an electric furnace heated to 300 ° C. After that, dry air was further added for 4 hours.
A solid phase reaction step of flowing at a flow rate of 2 l / hr for 20 minutes, followed by a firing step of flowing air containing 3% of ammonia and 4 mg / l of steam at a flow rate of 72 l / hr for 20 minutes,
The powder was alternately repeated six times to obtain a powder (hereinafter referred to as “powder 4”).

Example 5 58 g of diphosphorus pentoxide, 2 of urea
6 g, 9 g of ammonium bicarbonate and 7 g of diammonium hydrogen phosphate were mixed, and a solid phase reaction was performed by flowing dry air at a flow rate of 42 l / hr for 120 minutes while stirring in an electric furnace heated to 280 ° C. After that, dry air was further added to 42
The solid-state reaction step of flowing at a flow rate of 1 / hr for 20 minutes and the firing step of flowing air containing 3% of ammonia and 4 mg / l of water vapor at a flow rate of 42 l / hr for 20 minutes are alternately performed six times. A powder (hereinafter referred to as “powder 5”) was obtained repeatedly.

Example 6 58 g of diphosphorus pentoxide, 2 urea
6 g, 9 g of ammonium bicarbonate and 7 g of diammonium hydrogen phosphate were mixed, and a solid phase reaction was carried out by flowing dry air at a flow rate of 72 l / hr for 120 minutes while stirring in an electric furnace heated to 300 ° C. After that, dry air was further added for 72 hours.
The solid-phase reaction step of flowing at a flow rate of 1 / hr for 20 minutes and the firing step of flowing air containing 3% of ammonia and 4 mg / l of water vapor at a flow rate of 72 l / hr for 20 minutes are alternately performed six times. A powder (hereinafter referred to as “powder 6”) was obtained repeatedly.

Comparative Example 1 Diammonium hydrogen phosphate 1
00g and 30g of urea were mixed and reacted and fired for 240 minutes in a closed atmosphere while stirring in an electric furnace heated to 280 ° C to obtain a powder (hereinafter referred to as "powder 7").

Comparative Example 2 Diphosphorus pentoxide 30 g, urea 3
0 g and 50 g of diammonium hydrogen phosphate.
While stirring in an electric furnace heated to 0 ° C., ammonia gas was flowed at a flow rate of 40 l / hr for 240 minutes to fire and react to obtain a powder (hereinafter referred to as “powder 8”).

Table 1 shows crystal forms and average diameters of particles of the powders 1 to 8 obtained in Examples 1 to 6 and Comparative Examples 1 and 2 as observed by an electron microscope. As shown in this table and FIGS. 1 and 2, the crystals of ammonium polyphosphate according to the present invention are different from those of the comparative example, and all have an average diameter of 10 μm.
m or less.

[Table 1]

2. Production and Evaluation of Resin Containing Granular Crystals of Ammonium Polyphosphate 150 g of each of powders 1 to 8 obtained in Examples 1 to 6 and Comparative Examples 1 and 2 were each used as a polypropylene-ethylene block copolymer resin. 660 g, a silane coupling agent (trialkoxysilane) 15 g, and magnesium hydroxide (average particle diameter 5 μm or less) 175 g) were mixed and melt-kneaded and extruded with an extruder to obtain pellets. And molded each with several 60 × 49 ×
2.5 mm test pieces (hereinafter referred to as “test piece 1” to “test piece 8”, respectively) were obtained.

When the ammonium polyphosphate crystal according to the present invention was kneaded and mixed with a resin or the like, excellent fluidity and excellent dispersibility were observed.

The obtained test piece was subjected to a flame retardancy test.
Evaluation based on the method defined in UL standard UL94,
The bleed resistance is set in a constant temperature bath at 80 ° C and 80% humidity.
It was taken out every day, dried with a constant temperature drier at 80 ° C., and changes in the surface of the dried test specimen were observed. Table 2 shows the results.
It was shown to. As shown in this table, the resin containing the ammonium polyphosphate granular crystals according to the present invention had excellent flame retardancy and bleed resistance.

[Table 2]

[0023]

The method for producing granular ammonium polyphosphate crystals according to the present invention has the above-mentioned structure, and has an average diameter of 10 μm distributed in the range of 3 to 15 μm.
The following, and is what enables the production of rice-grain crystals having a smooth surface, and the obtained smooth rice-granular crystals have excellent fluidity and dispersibility, and When mixed and used, it provides the resin with excellent flame retardancy and bleed resistance, and greatly contributes to industrial development.

[Brief description of the drawings]

FIG. 1 is a micrograph (magnification: 5000) of a granular crystal of ammonium polyphosphate according to the present invention (Example 6).

FIG. 2 is a micrograph (magnification: 5000) of a conventional ammonium polyphosphate crystal (Comparative Example 1).

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C01B 25/40 CA (STN)

Claims (1)

(57) [Claims] 1. A method according to claim 1, wherein diphosphorus pentoxide, a condensing agent such as urea and melamine, and an ammoniating agent such as ammonium phosphate, ammonium carbonate and ammonium hydrogencarbonate are mixed in an amount of at least 1.2 mol of nitrogen to 1 mol of phosphorus. Mix at a ratio of 270
A step of heating to 320 ° C. and performing a solid phase reaction process in dry air and a firing process in an atmosphere of a mixture of ammonia and water vapor, wherein the process is repeated 5 to 12 times. Production method