阅读说明：本技术 一种沸石咪唑酯骨架材料包覆红磷阻燃剂及其制备方法 (Zeolite imidazole ester framework material coated red phosphorus flame retardant and preparation method thereof ) 是由 李叙和 周喜 贺琪淇 于 2020-11-06 设计创作，主要内容包括：本发明提出了一种沸石咪唑酯骨架材料包覆红磷阻燃剂的制备方法,该方法包括：(1)将红磷和可溶性的锌盐分散在水中,得到分散液A,其中,红磷与锌盐中Zn~(2+)的摩尔比为2～8：1；(2)将2-甲基咪唑及水混合配成溶液B,其中,2-甲基咪唑与步骤(1)锌盐中Zn~(2+)的摩尔比为4～10：1；(3)将分散液A与溶液B混合,反应得到的沉淀物经脱水干燥,得到沸石咪唑酯骨架材料包覆红磷阻燃剂。本发明提供的沸石咪唑酯骨架材料包覆红磷阻燃剂具有白度高、抗氧化性好和阻燃效率高的特点,且制备方法工艺简单,易于实施。(The invention provides a preparation method of a zeolite imidazole ester framework material coated red phosphorus flame retardant, which comprises the following steps: (1) dispersing red phosphorus and soluble zinc salt in water to obtain dispersion liquid A, wherein the red phosphorus and Zn in the zinc salt 2+ The molar ratio of (A) to (B) is 2-8: 1; (2) mixing 2-methylimidazole with water to prepare a solution B, wherein the 2-methylimidazole is mixed with Zn in the zinc salt in the step (1) 2+ The molar ratio of (a) to (b) is 4-10: 1; (3) and mixing the dispersion liquid A and the solution B, and dehydrating and drying the precipitate obtained by reaction to obtain the zeolite imidazole ester framework material-coated red phosphorus flame retardant. The zeolite imidazole ester framework material coated red phosphorus flame retardant provided by the invention has the characteristics of high whiteness, good oxidation resistance and high flame retardant efficiency, and the preparation method is simple in process and easy to implement.)

1. A preparation method of a zeolite imidazole ester framework material coated red phosphorus flame retardant is characterized by comprising the following steps:

(1) dispersing red phosphorus and soluble zinc salt in water to obtain dispersion liquid A, wherein the red phosphorus and Zn in the zinc salt²⁺The molar ratio of (A) to (B) is 2-8: 1;

(2) mixing 2-methylimidazole with water to prepare a solution B, wherein the 2-methylimidazole is mixed with Zn in the zinc salt in the step (1)²⁺The molar ratio of (a) to (b) is 4-10: 1;

(3) and mixing the dispersion liquid A and the solution B, and dehydrating and drying the precipitate obtained by reaction to obtain the zeolite imidazole ester framework material-coated red phosphorus flame retardant.

2. The method of claim 1, wherein the zinc salt is zinc nitrate, zinc chloride or zinc sulfate.

3. The preparation method of the zeolite imidazolate framework material-coated red phosphorus flame retardant according to claim 1, wherein the mass ratio of red phosphorus to water in the step (1) is 1-30: 100.

4. the preparation method of the zeolite imidazolate framework material-coated red phosphorus flame retardant according to claim 1, wherein the mass ratio of 2-methylimidazole to water in the step (2) is 1-30: 100.

5. the method for preparing a red phosphorus flame retardant coated with a zeolitic imidazolate framework material according to claim 1, wherein the mixing of the dispersion a with the solution B is specifically: and adding the dispersion liquid A and the solution B into a reaction kettle, keeping the reaction temperature at 20-60 ℃, and continuously stirring for reaction for 5-30 hours.

6. The red phosphorus flame retardant coated by the zeolitic imidazolate framework material is prepared by the method of any one of claims 1 to 5, and is characterized in that the surface of the red phosphorus is coated by the zeolitic imidazolate framework material, wherein the zeolitic imidazolate framework material is ZIF-8.

Technical Field

The invention relates to the field of flame retardant materials, and particularly relates to a zeolite imidazolate framework material-coated red phosphorus flame retardant and a preparation method thereof.

Background

Compared with other halogen-free flame retardants, the red phosphorus flame retardant has the advantages of high flame retardant efficiency, small using amount and the like, and is widely applied to the fields of rubber, nylon, polyester, epoxy resin, polyurethane and the like. However, pure red phosphorus has the defects of easy moisture absorption, unstable property, poor compatibility with high polymer materials, easy coloring and the like. After the red phosphorus is coated, the stability is improved, and the compatibility with a high polymer material is better. In addition, after the purple red of the red phosphorus is covered by the capsule material, the color and luster of the coated red phosphorus are relatively light, and the red phosphorus can be used for processing light-colored high polymer material products. Therefore, the coated red phosphorus serving as a flame retardant is added into a high polymer material, so that the defect of direct use of the red phosphorus can be overcome, and a considerable or even better flame retardant effect can be achieved.

At present, the mature red phosphorus coated product in the market is melamine resin coated red phosphorus, which takes melamine resin as a capsule wall material, has the characteristics of good oxidation resistance, low moisture absorption rate and good compatibility with high polymer materials, and is widely applied to processing of nylon, PET, PP and the like (pandeming, university of China and south, doctor thesis, 2004). However, melamine resin is transparent polymer resin, has poor covering property on red phosphorus color, has dark color, and cannot be used for processing light-colored polymer material products. In addition, the literature reports the preparation and application of aluminum hydroxide-coated red phosphorus and aluminum hydroxide-melamine resin double-layer-coated red phosphorus flame retardant (He Yingcui et al, chemical and adhesive 2014, 36: 279-281; Zhu-Chao et al, modern 2015, 35: 116-118). However, the whiteness and the flame retardant efficiency of the coated red phosphorus flame retardant still need to be further improved so as to meet the requirements of the coated red phosphorus flame retardant for processing light-colored high polymer material products.

Disclosure of Invention

The invention aims to provide a red phosphorus flame retardant coated by a zeolite imidazole ester framework material and a preparation method thereof.

The invention provides a preparation method of a zeolite imidazole ester framework material coated red phosphorus flame retardant, which comprises the following steps:

(1) dispersing red phosphorus and soluble zinc salt in water to obtain dispersion liquid A, wherein the red phosphorus and Zn in the zinc salt²⁺The molar ratio of (A) to (B) is 2-8: 1;

(2) mixing 2-methylimidazole with water to prepare a solution B, wherein the 2-methylimidazole is mixed with Zn in the zinc salt in the step (1)²⁺The molar ratio of (a) to (b) is 4-10: 1;

(3) and mixing the dispersion liquid A and the solution B, and dehydrating and drying the precipitate obtained by reaction to obtain the zeolite imidazole ester framework material-coated red phosphorus flame retardant.

Further, the zinc salt is zinc nitrate, zinc chloride or zinc sulfate.

Further, the mass ratio of red phosphorus to water in the step (1) is 1-30: 100.

further, in the step (2), the mass ratio of the 2-methylimidazole to the water is 1-30: 100.

further, the mixing of the dispersion liquid a and the solution B is specifically as follows: and adding the dispersion liquid A and the solution B into a reaction kettle, keeping the reaction temperature at 20-60 ℃, and continuously stirring for reaction for 5-30 hours.

The invention also provides a red phosphorus flame retardant coated with the zeolitic imidazolate framework material, which is prepared by a self-assembly method of red phosphorus, zinc salt and 2-methylimidazole, and is characterized in that the surface of the red phosphorus is coated with the zeolitic imidazolate framework material, wherein the zeolitic imidazolate framework material is ZIF-8.

The preparation method provided by the invention is simple in process and easy to implement. The zeolite imidazolate framework material can be uniformly coated on the surface of red phosphorus and has better color covering performance, so that the prepared zeolite imidazolate framework material coated red phosphorus flame retardant has the characteristic of high whiteness, thereby solving the problem that the red phosphorus flame retardant can not be used for processing light-color high polymer materials due to deeper color. In addition, the molecular structure of the zeolite imidazole ester framework material contains abundant nitrogen elements and zinc elements, and the zeolite imidazole ester framework material and red phosphorus have excellent flame retardant performance, so that the zeolite imidazole ester framework material coated red phosphorus flame retardant has the advantages of good oxidation resistance and high flame retardant efficiency.

Detailed Description

The following provides a more detailed description of the present invention. The above and other objects, features and advantages of the present invention will be apparent to those skilled in the art from the detailed description of the present invention.

The invention provides a preparation method of a zeolite imidazole ester framework material coated red phosphorus flame retardant, which comprises the following steps:

(1) dispersing red phosphorus and soluble zinc salt in water to obtain dispersion liquid A, wherein the red phosphorus and Zn in the zinc salt²⁺The molar ratio of (A) to (B) is 2-8: 1;

(2) mixing 2-methylimidazole with water to prepare a solution B, wherein the 2-methylimidazole is mixed with Zn in the zinc salt in the step (1)²⁺The molar ratio of (a) to (b) is 4-10: 1;

(3) and mixing the dispersion liquid A and the solution B, and dehydrating and drying the precipitate obtained by reaction to obtain the zeolite imidazole ester framework material-coated red phosphorus flame retardant.

In step (1), the zinc salt is preferably zinc nitrate, zinc chloride or zinc sulfate. The mass ratio of red phosphorus to water is preferably 1-30: 100. it should be clear that a person skilled in the art can also prepare other concentrations of red phosphorus dispersions.

In the step (2), the mass ratio of the 2-methylimidazole to the water is preferably 1-30: 100. one skilled in the art can also prepare solutions of other concentrations of 2-methylimidazole.

In the step (3), the dispersion liquid A and the solution B are mixed specifically as follows: and adding the dispersion liquid A and the solution B into a reaction kettle, keeping the reaction temperature at 20-60 ℃, and continuously stirring for reaction for 5-30 hours.

The invention coats the zeolite imidazole ester framework material on the surface of red phosphorus by a self-assembly method, and the related preparation method has simple process and is easy to implement. The zeolite imidazolate framework material can be uniformly coated on the surface of red phosphorus and has better color covering performance, so that the prepared zeolite imidazolate framework material coated red phosphorus flame retardant has the characteristic of high whiteness, thereby solving the problem that the red phosphorus flame retardant can not be used for processing light-color materials due to deeper color.

In addition, the molecular structure of the zeolite imidazole ester framework material contains abundant nitrogen elements and zinc elements, and the zeolite imidazole ester framework material and red phosphorus have excellent flame retardant performance, so that the zeolite imidazole ester framework material coated red phosphorus flame retardant has the advantages of good oxidation resistance and high flame retardant efficiency.

The following will illustrate the preparation of the zeolitic imidazolate framework material coated red phosphorus flame retardant in several exemplary embodiments.

Example 1

Dispersing 0.5 mol of red phosphorus and 0.1 mol of zinc nitrate in 300 mL of water to obtain a dispersion liquid A, mixing 0.8 mol of 2-methylimidazole with 300 mL of water to prepare a solution B, adding the dispersion liquid A and the solution B into a reaction kettle, keeping the reaction temperature at 30 ℃, continuously stirring for reaction for 20 hours, and dehydrating and drying a precipitate obtained by the reaction to obtain the zeolite imidazole ester framework material-coated red phosphorus flame retardant.

Example 2

Dispersing 0.2 mol of red phosphorus and 0.1 mol of zinc chloride in 100 mL of water to obtain a dispersion liquid A, mixing 0.4 mol of 2-methylimidazole with 130 mL of water to prepare a solution B, adding the dispersion liquid A and the solution B into a reaction kettle, keeping the reaction temperature at 20 ℃, continuously stirring for reaction for 30 hours, and dehydrating and drying a precipitate obtained by the reaction to obtain the zeolite imidazole ester framework material-coated red phosphorus flame retardant.

Example 3

Dispersing 0.8 mol of red phosphorus and 0.1 mol of zinc sulfate in 1800 mL of water to obtain a dispersion liquid A, mixing 1.0 mol of 2-methylimidazole and 1600 mL of water to prepare a solution B, adding the dispersion liquid A and the solution B into a reaction kettle, keeping the reaction temperature at 60 ℃, continuously stirring for reaction for 5 hours, and dehydrating and drying a precipitate obtained by the reaction to obtain the zeolite imidazole ester framework material-coated red phosphorus flame retardant.

Performance test experiments:

the red phosphorus sample coated with the zeolitic imidazolate framework material prepared in examples 1 to 3 and the red phosphorus sample coated with commercially available melamine resin-coated red phosphorus and aluminum hydroxide were set as experimental groups 1 to 5, and the following tests were performed on equivalent samples of the experimental groups 1 to 5:

testing the red phosphorus content: weighing 0.5 g of sample, accurately obtaining 0.0002 g of sample, placing the sample in a 300 mL conical flask, adding water for wetting, adding 30 mL of bromine saturated nitric acid into a fume hood by using a funnel, and placing the mixture on an electric hot plate for 1 h to heat until bromine color disappears. After cooling, adding 1 g of potassium chlorate and 30 mL of hydrochloric acid, standing for 10 min, washing the funnel with a small amount of water, and then taking down; slowly heating the solution to about 10 mL, adding 200 mL of hot water, completely transferring the solution into a 500 mL volumetric flask, cooling, diluting the solution to a scale with water, shaking up, filtering, discarding 30 mL of initial filtrate, transferring 10 mL of filtrate into a 400 mL beaker by using a pipette, adding 80 mL of water, 10 mL of nitric acid solution and 50 mL of quinomolybdic citranone reagent, covering a watch glass, heating the solution in a water bath until the temperature of the content in the glass reaches 75 +/-5 ℃, keeping the temperature for 30s, cooling the solution to room temperature, and stirring the solution for 3-4 times in the cooling process; performing suction filtration by using a glass sand crucible with constant weight at 180 +/-5 ℃, washing the precipitate for 5-6 times by using a pouring method, using about 20 mL of water each time, transferring the precipitate into the glass sand crucible, continuously washing the glass sand crucible for 3-4 times by using the water, placing the glass sand crucible into an electrothermal drying oven at 180 +/-5 ℃ for drying for 45 min, taking out the glass sand crucible, placing the glass sand crucible into a dryer for cooling to room temperature, weighing, and accurately measuring to 0.0002 g; simultaneously, blank tests are carried out, and the results are shown in table 1;

and (3) whiteness testing: weighing 10.00 g of sample, tabletting, placing in a sample box, and testing on a digital display whiteness instrument, wherein the results are shown in table 1;

and (3) antioxidant test: respectively weighing 10.00 g of sample in a three-neck flask containing 200 ml of distilled water, boiling the solution for 1 hour, filtering, removing initial filtrate, adding 10.00 g of analytically pure sodium chloride into 100 ml of the filtrate, titrating oxyacid formed by oxidation in the filtrate by using a standard sodium hydroxide solution after dissolution, and expressing the oxidation resistance of oxyacid by the milligrams of sodium hydroxide consumed by each gram of red phosphorus, wherein the results are shown in table 1;

limiting oxygen index test: the test was carried out according to the method of GB/T2406.2-2009, and the addition amount of the coated red phosphorus flame retardant was 6%, and the results are shown in Table 1.

From the results in table 1, it can be seen that the zeolite imidazolate framework material coated red phosphorus flame retardant has high whiteness and flame retardant efficiency, and has good oxidation resistance. Compared with the existing melamine resin coated red phosphorus and aluminum hydroxide coated red phosphorus flame retardant, when a sample has the same or even higher red phosphorus content, the whiteness and the flame retardant efficiency of the zeolite imidazole ester framework material coated red phosphorus flame retardant are relatively higher, and the zeolite imidazole ester framework material coated red phosphorus flame retardant is suitable for processing light-color high polymer materials. The results show that the zeolite imidazolate framework material can be better coated on the surface of red phosphorus and has good color and luster covering performance. In addition, the zeolite imidazolate framework material and red phosphorus have excellent flame retardant performance, so that the flame retardant efficiency of the zeolite imidazolate framework material coated with the red phosphorus flame retardant is high.

It should be understood that although the present invention has been clearly illustrated by the foregoing examples, various changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the invention, and it is intended to cover all such changes and modifications as fall within the scope of the appended claims.