Preparation method of fine particle size ammonium polyphosphate

Abstract

The application discloses a preparation method of fine-particle-diameter ammonium polyphosphate, which comprises the following steps: S1, stirring and heating diaphosphorus pentoxide and diammonium hydrogen phosphate in a kneader to 220-250 DEG C; S2, opening ammonia passage, the ammonia passage amount is 0.1-0.5 m 3 / h per 100 kg of reaction materials, and reacting for 20-45 min; S3, heating to 260-320 DEG C, increasing the ammonia passage amount to 2-5 m 3 / h per 100 kg of reaction materials, and reacting for 3-5 hours; S4, stopping heating, reducing the ammonia passage amount to 0.5-1.9 m 3 / h per 100 kg of reaction materials, and reacting for 1-4 hours; S5, stopping the ammonia passage, and discharging when the reaction temperature is reduced to 150-200 DEG C; and S6, obtaining fine-particle-diameter ammonium polyphosphate after crushing. The fine-particle-diameter ammonium polyphosphate prepared by the method has an average particle diameter of 5-12 microns, uniform particle diameter distribution, low water solubility, better heat resistance, and better dispersion effect when applied in resin.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for preparing fine particle size ammonium polyphosphate. BACKGROUND

[0002] Ammonium polyphosphate, APP for short, is a phosphorus and nitrogen type environmental protection inorganic flame retardant. It has a wide application in the field of flame retardant of fireproof coating, resin, rubber paper, wood, fiber, etc. It has the characteristics of low toxicity and low smoke. The particle size of ammonium polyphosphate is generally 15-20 microns. The finer the particle size of inorganic flame retardant, the larger the surface area, the larger the contact area with the polymer, the better the dispersion and compatibility, and the obvious improvement of the flame retardant effect. The particle size of ammonium polyphosphate used in plastics is relatively large, which affects the dispersion effect and the flame retardant effect is poor. At present, it is generally used after grinding or crushing and then coated with a coating.

[0003] Patent publication number CN101254908B discloses a method for preparing high-heat-resistant crystalline type II ammonium polyphosphate. The method uses a mixture of diammonium hydrogen phosphate and diaphosphorus pentoxide for reaction, and then sprays a high-concentration urea solution after ammonia is passed. The product produced by this method has a small particle size, and the average particle size is less than 10 microns. However, the large amount of water in the urea solution affects the condensation reaction in the synthesis process, which easily causes uneven polymerization degree and poor heat resistance of the product, with an initial decomposition temperature of 270-275℃.

[0004] Patent publication number CN101597044A discloses a method for preparing crystalline type II ammonium polyphosphate with high polymerization degree and narrow molecular weight distribution. The method uses equimolar mixture of diammonium hydrogen phosphate and diaphosphorus pentoxide for reaction, and then passes a large amount of inert gas in the initial process, and carries out the reaction by passing, stopping and re-passing ammonia gas, and using a surface treatment agent (selected from one of melamine cyanurate, amino silane, epoxy resin, active melamine, or isocyanate). Although the product obtained is a fine particle size ammonium polyphosphate product (less than 12 microns). The production process requires the passage of inert gases such as nitrogen, helium, and argon, which increases the production cost; the production control process and operation steps are complex, and the equipment requirements are high.

[0005] Patent publication number CN111807343B discloses a method for preparing fine particle size ammonium polyphosphate and its application. In the synthesis process of ammonium polyphosphate, 0.5%-3% of ammonium polyphosphate powder with insufficient ammonia is added to obtain crystalline type II ammonium polyphosphate product with controlled fine particle size. This method can control the proportion of fine particle size of the final product, and the proportion of fine particle size ≤2.19μm is less than or equal to 2%, but the average particle size of the product is still about 17-20 microns. SUMMARY

[0006] In view of the above defects, the application provides a preparation method of fine particle size ammonium polyphosphate, the average particle size of the prepared fine particle size ammonium polyphosphate is 5-12 microns, the product has uniform particle size distribution, low water solubility, good heat resistance, and better dispersion effect when applied in resin.

[0007] The technical scheme is as follows: a preparation method of fine particle size ammonium polyphosphate, comprising the following steps:

[0008] S1, stirring and heating the phosphorus pentoxide and the diammonium hydrogen phosphate in a kneader to 220-250 DEG C;

[0009] S2, opening the ammonia passage, the ammonia passage amount is 0.1-0.5 m 3 / h per 100 kg of reaction materials, and reacting for 20-45 min;

[0010] S3, heating to 260-320 DEG C, increasing the ammonia passage amount to 2-5 m 3 / h per 100 kg of reaction materials, and reacting for 3-5 hours;

[0011] S4, stopping heating, reducing the ammonia passage amount to 0.5-1.9 m 3 / h per 100 kg of reaction materials, and reacting for 1-4 hours;

[0012] S5, stopping the ammonia passage, and discharging the product when the reaction temperature is reduced to 150-200 DEG C, to obtain the coarse product of fine particle size ammonium polyphosphate;

[0013] S6, crushing to obtain the fine particle size ammonium polyphosphate.

[0014] Optionally, the molar ratio of the phosphorus pentoxide to the diammonium hydrogen phosphate is 1.05:1-1:1.

[0015] Optionally, the molar ratio of the phosphorus pentoxide to the diammonium hydrogen phosphate is 1:1.

[0016] Optionally, in S1, a process modifier is further added in the kneader, the process modifier is a mixture of white carbon black and melamine diamide.

[0017] Optionally, the amount of the process modifier is 0.1-0.5% of the sum of the weight of the phosphorus pentoxide and the weight of the diammonium hydrogen phosphate.

[0018] Optionally, the process modifier is made of ammonia water, melamine diamide and white carbon black.

[0019] Optionally, the process modifier is made by the following steps:

[0020] (1) heating the ammonia water to 40-80 DEG C, adding the melamine diamide, stirring and dissolving for 15-45 min to form a solution;

[0021] (2) the solution (1) is uniformly sprayed on the white carbon black in a high-speed mixer, and dried to obtain the process modifier.

[0022] Optionally, the ammonia water is 0.5-10% ammonia water.

[0023] Optionally, the weight ratio of the ammonia water to the melamine diamide is 4:1-19:1.

[0024] Optionally, the weight ratio of the solution to the white carbon black is 1:20-1:5.

[0025] Optionally, the average particle size of the fine-particle-size ammonium polyphosphate crude product is 6-14 microns, and the average particle size of the fine-particle-size ammonium polyphosphate is 5-12 microns.

[0026] Invention principle:

[0027] In the present application, the ultra-low ammonia ammonia passage reaction used in the first step reaction condenses the hydroxyl group of the melamine diamide with the phosphorus pentoxide to produce melamine diamide phosphate; the ultra-low ammonia ammonia passage reaction is beneficial to the initial violent reaction of the phosphorus pentoxide, makes the polymerization reaction more uniform, avoids excessive reaction, makes the polymerization degree quickly increase, and the reaction system quickly becomes viscous, so that the dispersion of the modifier becomes difficult.

[0028] When the second step increases the ammonia passage amount, the temperature rises quickly, the melamine diamide phosphate participates in the ammonium polyphosphate polymerization reaction, the polymerization reaction with the participation of the melamine diamide phosphate, the molecular chain unidirectionally grows, in the subsequent cooling process, the melamine diamide end is more prone to form a crystal nucleus. The white carbon black absorbs the melamine diamide, promotes the rapid dispersion of the melamine diamide in the system, and makes the reaction more uniform; after stopping heating, the system starts to slowly cool down, the melamine diamide end absorbed by the white carbon black first forms a crystal nucleus, so that the ammonium polyphosphate molecules can be quickly and uniformly powdered, and the particle size becomes more uniform and smaller. Specific implementation

[0029] The present application will be further described below.

[0030] In the following specific implementation:

[0031] The melamine diamide is commercially available.

[0032] The white carbon black is commercially available.

[0033] The phosphorus pentoxide is commercially available.

[0034] The industrial diammonium hydrogen phosphate is commercially available.

[0035] Preparation of the process modifier in Example 1

[0036] (1) 1000 g of 5 wt% ammonia water was heated to 60°C, 100 g of melamine diamide powder was added, and stirred for 30 minutes to form a solution.

[0037] (2) The solution of (1) was uniformly sprayed on 10 kg of white carbon black in a high-speed mixer, and dried to obtain a process modifier (10.1 kg).

[0038] The process modifier prepared in this example was used in Examples 2-4 below.

[0039] Example 2

[0040] S1, 250 kg of phosphorus pentoxide and 500 g of the process modifier of Example 1 were added to a kneader, and stirred for 10 minutes; then 232 kg of diammonium phosphate was added, and the temperature was raised to 230°C;

[0041] S2, ammonia was introduced at a rate of 0.3 m 3 / h per 100 kg of reaction material, and reacted for 30 minutes;

[0042] S3, the temperature was raised to 290°C, and the ammonia flow rate was increased to 4.5 m 3 / h per 100 kg of reaction material, and reacted for 4.5 hours;

[0043] S4, the heating was stopped, and the ammonia flow rate was reduced to 1 m 3 / h per 100 kg of reaction material, and reacted for 2.5 hours;

[0044] S5, the ammonia was stopped, and when the reaction temperature dropped to 160°C, the product was discharged to obtain fine particle size ammonium polyphosphate crude product 1;

[0045] S6, the crude product was ground by a mechanical mill, and then air classified, with a feeding speed of 25 kg / min, a classifier speed of 1000 r / min, a main machine speed of 1160 r / min, and an air flow of 3800 m 3 / h, to obtain fine particle size ammonium polyphosphate 1 after grinding.

[0046] The fine particle size ammonium polyphosphate crude product 1 and the fine particle size ammonium polyphosphate 1 were detected, and the results are shown in Tables 1-2.

[0047] Example 3

[0048] S1, 250 kg of phosphorus pentoxide and 1400 g of the process modifier of Example 1 were added to a kneader, and stirred for 10 minutes; then 232 kg of diammonium phosphate was added, and the temperature was raised to 230°C;

[0049] S2, ammonia was introduced at a rate of 0.3 m 3 / h per 100 kg of reaction material, and reacted for 30 minutes;

[0050] S3, temperature is raised to 290°C, ammonia flow is increased to 4.5 m 3 / h, reaction is carried out for 4.5 hours;

[0051] S4, heating is stopped, ammonia flow is decreased to 1 m 3 / h, reaction is carried out for 2.5 hours;

[0052] S5, ammonia flow is stopped, when the reaction temperature is decreased to 160°C, the product is discharged, to obtain fine particle size ammonium polyphosphate crude product 2;

[0053] S6, the crude product is mechanically ground and air classified, the feeding speed is 25 kg / min, the classifier speed is 1000 r / min, the main machine speed is 1160 r / min, the air volume of the air blower is 3800 m 3 / h, after grinding, fine particle size ammonium polyphosphate 2 is obtained.

[0054] The fine particle size ammonium polyphosphate crude product 2 and the fine particle size ammonium polyphosphate 2 are detected, and the results are shown in Tables 1-2.

[0055] Example 4

[0056] S1, 250 kg of phosphorus pentoxide and 2400 g of the process modifier of Example 1 are taken into a kneader, stirring is started for 10 minutes, and then 232 kg of diammonium hydrogen phosphate is added; the stirring is increased to 230°C;

[0057] S2, ammonia flow is started, the ammonia flow is 0.3 m 3 / h, reaction is carried out for 30 minutes;

[0058] S3, temperature is raised to 290°C, ammonia flow is increased to 4.5 m 3 / h, reaction is carried out for 4.5 hours;

[0059] S4, heating is stopped, ammonia flow is decreased to 1 m 3 / h, reaction is carried out for 2.5 hours;

[0060] S5, ammonia flow is stopped, when the reaction temperature is decreased to 160°C, the product is discharged, to obtain fine particle size ammonium polyphosphate crude product 3;

[0061] S6, the crude product is mechanically ground and air classified, the feeding speed is 25 kg / min, the classifier speed is 1000 r / min, the main machine speed is 1160 r / min, the air volume of the air blower is 3800 m 3 / h, after grinding, fine particle size ammonium polyphosphate 3 is obtained.

[0062] The fine particle size ammonium polyphosphate crude product 3 and the fine particle size ammonium polyphosphate 3 are detected, and the results are shown in Tables 1-2.

[0063] Example 5

[0064] S1, 250 kg of phosphorus pentoxide and 232 kg of diammonium hydrogen phosphate were added into a kneader, and the temperature was raised to 230°C under stirring;

[0065] S2, ammonia was introduced at a rate of 0.3 m3 / h per 100 kg of reactant, and the reaction was carried out for 30 minutes;

[0066] S3, the temperature was raised to 290°C, and the ammonia introduction rate was increased to 4.5 m3 / h per 100 kg of reactant, and the reaction was carried out for 4.5 hours; 3

[0067] S4, the heating was stopped, and the ammonia introduction rate was decreased to 1 m3 / h per 100 kg of reactant, and the reaction was carried out for 2.5 hours; 3

[0068] S5, the ammonia introduction was stopped, and the product was discharged when the reaction temperature dropped to 160°C, to obtain crude ammonium polyphosphate product 1;

[0069] S6, the crude ammonium polyphosphate product 1 was ground by a mechanical grinder, and then air classified, at a feeding speed of 25 kg / min, a classifier speed of 1000 r / min, a main machine speed of 1160 r / min, and an air volume of 3800 m3 / h of an air blower, to obtain ammonium polyphosphate 1 after grinding. 3

[0070] The crude ammonium polyphosphate product 1 and the ammonium polyphosphate 1 were detected, and the results are shown in Tables 1-2.

[0071] Comparative Example 1

[0072] S1, 250 kg of phosphorus pentoxide and 232 kg of diammonium hydrogen phosphate were added into a kneader, and the temperature was raised to 290°C under stirring;

[0073] S2, ammonia was introduced at a rate of 4.5 m3 / h per 100 kg of reactant, and the reaction was carried out for 4.5 hours; 3

[0074] S3, the ammonia introduction rate was decreased to 1 m3 / h per 100 kg of reactant, and the reaction was carried out for 3 hours; 3

[0075] S4, the ammonia introduction was stopped, and the product was discharged when the reaction temperature dropped to 160°C, to obtain crude ammonium polyphosphate product 2;

[0076] S5, the crude ammonium polyphosphate product 2 was ground by a mechanical grinder, and then air classified, at a feeding speed of 25 kg / min, a classifier speed of 1000 r / min, a main machine speed of 1160 r / min, and an air volume of 3800 m3 / h of an air blower, to obtain ammonium polyphosphate 2 after grinding. 3 ​​​​​​

[0077] S6, taking ammonium polyphosphate 2, by airflow crushing to obtain ammonium polyphosphate 3. Crushing conditions: the compressed air with atmospheric dew point of ~ 25℃, the control pressure of 0.7 MPa, 7 m 3 / min, into the airflow crusher, the speed of the classifier 1100 r / min, while controlling the ammonium polyphosphate crude product 2 feeding amount of 15 kg / min.

[0078] The ammonium polyphosphate crude product 2, ammonium polyphosphate 2 and ammonium polyphosphate 3 were detected, and the results are shown in Tables 1-2.

[0079] Comparative Example 2

[0080] S1, taking 250 kg of phosphorus pentoxide and 232 kg of diammonium hydrogen phosphate into the kneader, stirring to 230℃;

[0081] S2, open the ammonia, the amount of ammonia is 1 m 3 / h per 100 kg of reaction material, reaction for 30 minutes;

[0082] S3, heating to 290℃, increasing the amount of ammonia to 4.5 m 3 / h per 100 kg of reaction material, reaction for 4.5 hours;

[0083] S4, stop heating, reduce the amount of ammonia to 1 m 3 / h per 100 kg of reaction material, reaction for 2.5 hours;

[0084] S5, stop the ammonia, when the reaction temperature drops to 160℃, discharge, to obtain ammonium polyphosphate crude product 3;

[0085] S6, ammonium polyphosphate crude product 3 product is mechanically ground and crushed, the feeding speed is 25 kg / min, the speed of the classifier is 1000 r / min, the speed of the main machine is 1160 r / min, the air volume of the air blower is 3800 m 3 / h, after crushing to obtain ammonium polyphosphate 4.

[0086] The ammonium polyphosphate 4 was detected, and the results are shown in Tables 1-2.

[0087] Table 1

[0088]

[0089] Table 2

[0090]

[0091]

[0092] It can be obviously seen from the table that the product of the application has high heat resistance, more uniform and small particle size, is particularly suitable for polyester processing, is easy to be better uniformly dispersed, and improves the flame-retardant efficiency.

[0093] The above only describes the preferred embodiments of the application and is not intended to limit the application. The application can be variously changed and modified by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A method for preparing fine particle size ammonium polyphosphate, comprising the following steps: S1, stirring and heating the mixture of phosphorus pentoxide and diammonium hydrogen phosphate in a kneader to 220-250℃; S2, open ammonia passage, ammonia passage amount is 0.1-0.5 m3 per 100 kg of reactant material 3 / h, reaction for 20-45 min; S3, temperature is raised to 260~320℃, ammonia flow is increased to 2~5m per 100kg of reaction material 3 / h, reaction time is 3~5 hours; S4, stop heating, reduce the amount of ammonia to 0.5-1.9 m 3 / h, react for 1-4 hours; S5, stopping the ammonia flow, and discharging the product when the reaction temperature drops to 150-200℃ to obtain the crude fine particle size ammonium polyphosphate; S6, obtaining the fine particle size ammonium polyphosphate after crushing; In S1, a process modifier is added to the kneader, wherein the process modifier is made of ammonia water, melamine diamide and white carbon black; The process modifier is made by the following steps: (1) heating the ammonia water to 40-80℃, adding the melamine diamide, and stirring and dissolving for 15-45 minutes to form a solution; (2) uniformly spraying the solution of (1) onto the white carbon black in a high-speed mixer, and drying to obtain the process modifier; The average particle size of the crude fine particle size ammonium polyphosphate is 6-14 microns, and the average particle size of the fine particle size ammonium polyphosphate is 5-12 microns.

2. The method of claim 1, wherein the fine particle size APP is prepared by the process of claim 1, wherein the fine particle size APP has a D50 of 5 to 15 μιη. The molar ratio of the phosphorus pentoxide to the diammonium hydrogen phosphate is 1.05:1-1:

1.

3. The method of producing fine-particle diam eter ammonium polyphosphate according to claim 2, characterized by, The molar ratio of the phosphorus pentoxide to the diammonium hydrogen phosphate is 1:

1. The weight of the process modifier is 0.1-0.5% of the sum of the weight of the phosphorus pentoxide and the weight of the diammonium hydrogen phosphate.

4. The method of claim 1, wherein the fine particle size APP is characterized by, The ammonia water is 0.5-10wt% ammonia water.

5. The method of claim 1, wherein the fine particle size APP is characterized by, The weight ratio of the ammonia water to the melamine diamide is 4:1-19:1; and / or 6. The method of producing fine-particle diam eter ammonium polyphosphate according to claim 1, characterized by The weight ratio of the solution to the white carbon black is 1:20-1:

5. ​

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