Preparation method and application of ammonium magnesium phosphate-melamine composite flame retardant

Abstract

The invention discloses a preparation method and application of an ammonium magnesium phosphate-melamine composite flame retardant, and the preparation method comprises the following steps: firstly, preparing melamine and triammonium phosphate into a mixed solution, and then dropwise adding a soluble magnesium salt solution into the mixed solution for full reaction to obtain the ammonium magnesium phosphate-melamine composite flame retardant. The prepared ammonium magnesium phosphate-melamine composite flame retardant has the characteristics of being insoluble in water, high in phosphorus content and high in nitrogen content, and magnesium element is added, so that when the ammonium magnesium phosphate-melamine composite flame retardant is applied to a high polymer material, the precipitation phenomenon does not exist, the addition amount of the flame retardant can be reduced on the premise of ensuring the flame retardant effect, and the flame retardant efficiency is improved. The mechanical property of the composite material is improved.

Description

Technical Field

[0001] The invention relates to the technical field of flame retardant preparation and application of the prepared flame retardant, and in particular to a preparation method of an ammonium magnesium phosphate-melamine composite flame retardant and application thereof. Background Art

[0002] Ammonium polyphosphate is the main type of phosphorus-nitrogen flame retardant. It has high phosphorus and nitrogen content, good thermal stability, is nearly neutral, can be mixed with other flame retardants, has good dispersibility, and has the advantages of low price, low toxicity, and safe use. Therefore, it is widely used in the preparation of intumescent fire retardant coatings, cable fire protection, paper and wood flame retardant treatment, and can also be used in flame retardant products of plastics and rubber. It is an environmentally friendly flame retardant. However, since ammonium polyphosphate is a polymer of ammonium phosphate, it still retains the property of ammonium phosphate being easily soluble in water, resulting in precipitation, moisture absorption, and decomposition during the plastic flame retardant processing, which greatly reduces its flame retardant effect.

[0003] At the same time, as a derivative of ammonium phosphate, ammonium magnesium phosphate has the property of being difficult to dissolve in water, which ammonium phosphate does not have, and it also contains the flame retardant element magnesium. When used as a flame retardant, although ammonium magnesium phosphate has the characteristics of high phosphorus content, its nitrogen content is not high enough and the phosphorus-nitrogen ratio is unreasonable. It is often necessary to increase the amount of addition to achieve the same flame retardant effect as ammonium polyphosphate, and increasing the amount of magnesium ammonium phosphate will damage the mechanical properties of the flame retardant material. Summary of the invention

[0004] In view of the drawbacks of the prior art, the first object of the present invention is to provide a method for preparing an ammonium magnesium phosphate-melamine composite flame retardant, comprising the following steps:

[0005] (1) dissolving triammonium phosphate in water to form a triammonium phosphate solution, and then adding melamine and stirring to form a mixed solution A;

[0006] (2) maintaining the temperature of the reaction system at 60° C. to 80° C., slowly dropping the soluble magnesium salt solution into the mixed solution A, and reacting the soluble magnesium salt with triammonium phosphate to form ammonium magnesium phosphate;

[0007] (3) After the reaction is completed, the reaction system is heated to 80° C. to 100° C. to allow ammonium magnesium phosphate and melamine to fully react; after the reaction is completed, the system is filtered, washed, dried, crushed and ground to obtain an ammonium magnesium phosphate-melamine composite flame retardant.

[0008] Further, the following steps are included:

[0009] (1) dissolving triammonium phosphate in deionized water to form a triammonium phosphate solution of a certain concentration, adding an appropriate amount of melamine and stirring to form a mixed solution A;

[0010] (2) Mixed solution A is heated to 60° C. to 80° C., a soluble magnesium salt is dissolved in deionized water to form a soluble magnesium salt solution of a certain concentration, and the solution is slowly added dropwise to mixed solution A under high-speed stirring. The temperature of the reaction system is maintained at 60° C. to 80° C. during the addition process. After all the addition is completed, the reaction is continued with stirring for 1 h to 3 h to allow the soluble magnesium salt to react with triammonium phosphate to generate ammonium magnesium phosphate;

[0011] (3) After the reaction is completed, the reaction system is heated to 80° C. to 100° C. for a reaction time of 2 h to 5 h to allow ammonium magnesium phosphate and melamine to fully react to form ammonium magnesium phosphate-melamine;

[0012] (4) After the reaction is completed, the precipitate is filtered, and the filter cake is washed with deionized water for 3-5 times. The filter cake is dried at 100° C. to 120° C., crushed and ground to obtain an ammonium magnesium phosphate-melamine composite flame retardant.

[0013] Furthermore, the concentration of the triammonium phosphate solution in step (1) is 25%-36%.

[0014] Furthermore, in the step (1), the mass ratio of triammonium phosphate to melamine is 1:(0.25-0.5).

[0015] Furthermore, the concentration of the soluble magnesium salt solution is 15%-25%.

[0016] Furthermore, the soluble magnesium salt is one of magnesium sulfate, magnesium chloride and magnesium nitrate.

[0017] Furthermore, the molar ratio of the soluble magnesium salt to the triammonium phosphate is 1:1-1:1.2.

[0018] The second object of the present invention is to provide an application of an ammonium magnesium phosphate-melamine composite flame retardant, wherein the ammonium magnesium phosphate-melamine composite flame retardant is used to prepare a flame retardant material.

[0019] Furthermore, the flame retardant material is flame retardant polypropylene, flame retardant PBT or flame retardant nylon.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0021] (1) The magnesium ammonium phosphate-melamine composite flame retardant prepared by the present invention is an integrated structure of magnesium ammonium phosphate and melamine, with a reasonable phosphorus-nitrogen ratio, and can achieve the same flame retardant effect as ammonium polyphosphate without increasing the addition amount. In addition, magnesium ammonium phosphate and melamine cooperate with each other to enhance the flame retardant effect.

[0022] (2) The magnesium ammonium phosphate-melamine composite flame retardant prepared by the present invention can simultaneously possess the characteristics of being poorly soluble in water and having high phosphorus and nitrogen content, so that when it is applied to flame retardant materials, it can avoid the risk of precipitation, reduce the amount of flame retardant added, and have little effect on the mechanical properties of the flame retardant materials.

[0023] (3) The ammonium magnesium phosphate-melamine composite flame retardant prepared by the present invention has the characteristics of organic matter due to the presence of melamine, which increases the compatibility with polymer materials and further improves the dispersion performance of the flame retardant.

[0024] (4) The by-product of the preparation method of the present invention is a soluble ammonium salt, which can be extracted and recovered to prepare fertilizer. DETAILED DESCRIPTION

[0025] The present invention is further analyzed below in conjunction with specific embodiments. Obviously, what is described is only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The following examples or comparative examples of the present invention use triammonium phosphate, melamine, ammonium polyphosphate, soluble magnesium salt, carbonizing agent CFA, PE wax, antioxidant 1010, and polypropylene, wherein the grade of the polypropylene is EP300M.

[0027] Example 1

[0028] (1) dissolving 15 g of triammonium phosphate in 45 g of deionized water to form a 25% triammonium phosphate solution, adding 3.75 g of melamine and stirring to form a mixed solution A;

[0029] (2) The temperature of the reaction system in the mixed solution A was raised to 60° C., 12 g of magnesium sulfate was dissolved in 68 g of deionized water to form a magnesium sulfate solution with a concentration of 15%, and the solution was slowly added dropwise to the mixed solution A under high-speed stirring. The temperature of the reaction system was maintained at 60° C. during the addition process. After all the additions were completed, the reaction was continued under stirring for 1 hour to generate ammonium magnesium phosphate;

[0030] (3) After the reaction is completed, the reaction system is heated to 80° C. and the reaction time is 2 h for full reaction; after the reaction is completed, the precipitate is filtered, the filter cake is washed with deionized water 3 times, the filter cake is dried at 100° C., crushed and ground to obtain ammonium magnesium phosphate-melamine composite flame retardant.

[0031] Example 2

[0032] (1) dissolving 15 g of triammonium phosphate in 27 g of deionized water to form a 36% triammonium phosphate solution, adding 7.5 g of melamine and stirring to form a mixed solution A;

[0033] (2) The reaction system in the mixed solution A was heated to 80° C., 9.5 g of magnesium hydrochloride was dissolved in 28.5 g of deionized water to form a 25% magnesium hydrochloride solution, which was slowly added dropwise to the mixed solution A under high-speed stirring. The temperature of the reaction system was maintained at 80° C. During the addition process, the reaction was stirred for 3 hours to generate ammonium magnesium phosphate.

[0034] (3) After the reaction is completed, the reaction system is heated to 100° C. and the reaction time is 5 hours for full reaction; after the reaction is completed, the precipitate is filtered, the filter cake is washed 4 times with deionized water, the filter cake is dried at 120° C., crushed and ground to obtain ammonium magnesium phosphate-melamine composite flame retardant.

[0035] Example 3

[0036] (1) dissolving 15 g of triammonium phosphate in 35 g of deionized water to form a 30% triammonium phosphate solution, adding 4.5 g of melamine and stirring to form a mixed solution A;

[0037] (2) The temperature of the reaction system in the mixed solution A was raised to 70° C., 15 g of magnesium nitrate was dissolved in 60 g of deionized water to form a 20% magnesium nitrate solution, and the solution was slowly added dropwise to the mixed solution A under high-speed stirring. The temperature of the reaction system was maintained at 70° C. during the addition process. After all the additions were completed, the reaction was continued under stirring for 2 h to generate ammonium magnesium phosphate;

[0038] (3) After the reaction is completed, the reaction system is heated to 90° C. and the reaction time is 3 h for full reaction; after the reaction is completed, the precipitate is filtered, the filter cake is washed with deionized water 3 times, the filter cake is dried at 110° C., crushed and ground to obtain an ammonium magnesium phosphate-melamine composite flame retardant.

[0039] Comparative Example 1

[0040] (1) dissolving 15 g of triammonium phosphate in 45 g of deionized water to form a triammonium phosphate solution with a concentration of 25%;

[0041] (2) The reaction system was heated to 60° C., 12 g of magnesium sulfate was dissolved in 68 g of deionized water to form a magnesium sulfate solution with a concentration of 15%, and the magnesium sulfate solution was slowly added dropwise to the triammonium phosphate solution under high-speed stirring. The temperature of the reaction system was maintained at 60° C. during the addition process. After all the additions were completed, the reaction was stirred for 1 hour to generate ammonium magnesium phosphate;

[0042] (3) After the reaction is completed, the precipitate is filtered, the filter cake is washed three times with deionized water, the filter cake is dried at 100° C., crushed and ground to obtain a finished product of ammonium magnesium phosphate.

[0043] The finished products prepared in Examples 1 to 3 and Comparative Example 1 and Comparative Example 2 respectively use ammonium polyphosphate, polypropylene, carbonizing agent CFA, PE wax, and antioxidant 1010 to prepare flame-retardant polypropylene materials, and the flame retardant properties, oxygen index, mechanical properties, precipitation, etc. of the flame-retardant polypropylene materials are tested. The specific test methods are as follows:

[0044] Impact strength: adopt the experimental method in GB / T 1843-2008 "Determination of cantilever beam impact strength of plastics";

[0045] Tensile properties: Adopt the experimental method in GB / T 1040-2008 "Determination of tensile properties of plastics";

[0046] Bending properties: Adopt the experimental method in GB / T 9341-2008 "Determination of bending properties of plastics";

[0047] Flame retardant grade UL94: adopt the vertical method in GB / T 2048-2008 "Horizontal and vertical methods for determination of combustion performance of plastics";

[0048] Oxygen index: The top surface ignition method in GB / T 2046-2008 "Determination of combustion behavior of plastics by oxygen index method" is adopted.

[0049] The specific formula is shown in Table 1, and the test results are shown in Table 2.

[0050] Table 1: Application formula

[0051] sample 1 2 3 4 5 Polypropylene (%) 74.7 72.7 76.7 76.7 76.7 PE wax (%) 1 1 1 1 1 Antioxidant 1010(%) 0.3 0.3 0.3 0.3 0.3 Carbon forming agent CFA (%) 6 6 6 6 6 Comparative Example 2: Ammonium polyphosphate (%) 18 / / / / Comparative Example 1: Ammonium magnesium phosphate (%) / 20 / / / Example 1 (%) / / 16 / / Example 2 (%) / / / 16 / Example 3 (%) / / / / 16

[0052] Table 2: Application results

[0053] Test items unit 1 2 3 4 5 Flame retardant grade / 0.8mm UL-94 V-0 V-0 V-0 V-0 V-0 Oxygen Index ％ 33 29 35 35 34.5 Tensile Strength MPa 21.94 15.63 23.91 23.86 23.18 Elongation at break ％ 106.25 95.34 138.63 135.95 130.27 Bending Strength MPa 29.72 21.34 34.95 32.81 30.96 Notched impact strength KJ / m2 7.7 5.2 9.16 9.03 8.89 Unnotched impact strength KJ / m2 68.06 31.27 68.58 68.53 68.37 Precipitation performance / Separation none none none none

[0054] It can be seen from Table 1 and Table 2 that in the flame retardant modification of polypropylene, the magnesium ammonium phosphate-melamine composite flame retardant prepared in Examples 1-3 is added to the formula. Compared with the addition of magnesium ammonium phosphate in Comparative Example 1 and the addition of ammonium polyphosphate in Comparative Example 2, the mechanical properties of the flame retardant material are better. When the addition amount of magnesium ammonium phosphate-melamine composite flame retardant is relatively small, the flame retardant performance can still reach V-0, the mechanical properties are more excellent, and there is no precipitation phenomenon.

[0055] The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as belonging to the protection of the present invention.

Claims

1. A method for preparing an ammonium magnesium phosphate-melamine composite flame retardant, characterized in that: The following steps are involved: (1) dissolving triammonium phosphate in water to form a triammonium phosphate solution, and then adding melamine and stirring to form a mixed solution A; (2) maintaining the temperature of the reaction system at 60° C. to 80° C., slowly dropping the soluble magnesium salt solution into the mixed solution A, and reacting the soluble magnesium salt with triammonium phosphate to form ammonium magnesium phosphate; (3) After the reaction is completed, the reaction system is heated to 80° C. to 100° C. to allow ammonium magnesium phosphate and melamine to react fully. After the reaction is completed, the system is filtered, washed, dried, crushed and ground to obtain an ammonium magnesium phosphate-melamine composite flame retardant.

2. The method for preparing the magnesium ammonium phosphate-melamine composite flame retardant according to claim 1, characterized in that: The following steps are involved: (1) dissolving triammonium phosphate in deionized water to form a triammonium phosphate solution of a certain concentration, adding an appropriate amount of melamine and stirring to form a mixed solution A; (2) Mixed solution A is heated to 60° C. to 80° C., a soluble magnesium salt is dissolved in deionized water to form a soluble magnesium salt solution of a certain concentration, and the solution is slowly added dropwise to mixed solution A under high-speed stirring. The temperature of the reaction system is maintained at 60° C. to 80° C. during the addition process. After all the addition is completed, the reaction is continued with stirring for 1 h to 3 h to allow the soluble magnesium salt to react with triammonium phosphate to generate ammonium magnesium phosphate; (3) After the reaction is completed, the reaction system is heated to 80° C. to 100° C. for a reaction time of 2 h to 5 h to allow the ammonium magnesium phosphate and melamine to fully react; after the reaction is completed, the precipitate is filtered, the filter cake is washed with deionized water for 3 to 5 times, the filter cake is dried at 100° C. to 120° C., and crushed to obtain an ammonium magnesium phosphate-melamine composite flame retardant.

3. The method for preparing the magnesium ammonium phosphate-melamine composite flame retardant according to claim 1 or 2, characterized in that: The concentration of the triammonium phosphate solution in step (1) is 25%-36%.

4. The method for preparing the magnesium ammonium phosphate-melamine composite flame retardant according to claim 1 or 2, characterized in that: In the step (1), the mass ratio of triammonium phosphate to melamine is 1:(0.25-0.5).

5. The method for preparing the magnesium ammonium phosphate-melamine composite flame retardant according to claim 1 or 2, characterized in that: The concentration of the soluble magnesium salt solution is 15%-25%.

6. The method for preparing the magnesium ammonium phosphate-melamine composite flame retardant according to claim 1 or 2, characterized in that: The soluble magnesium salt is one of magnesium sulfate, magnesium chloride and magnesium nitrate.

7. The method for preparing the magnesium ammonium phosphate-melamine composite flame retardant according to claim 1 or 2, characterized in that: The molar ratio of the soluble magnesium salt to the triammonium phosphate is 1:1-1:1.

2.

8. An application of the magnesium ammonium phosphate-melamine composite flame retardant obtained by any one of claims 1 to 7, characterized in that: The ammonium magnesium phosphate-melamine composite flame retardant is used for preparing flame retardant materials.

9. The use of the magnesium ammonium phosphate-melamine composite flame retardant according to claim 8, characterized in that: The flame retardant material is flame retardant polypropylene, flame retardant PBT or flame retardant nylon.