Preparation method of organic-inorganic composite high-whiteness composite microcapsule phosphorus flame retardant

Abstract

The invention relates to a preparation method of an organic-inorganic composite high-whiteness composite microcapsule phosphorus flame retardant, and belongs to the technical field of modification preparation of halogen-free flame retardants. The method comprises the following steps: putting a carrier material and a phosphorus elementary substance into a closed container, and separately placing the phosphorus elementary substance raw material and the carrier material in the same closed container; placing the closed container in a high-temperature furnace for heat treatment to sublimate elemental phosphorus, adsorbing phosphorus steam by the carrier material in the heating process, and cooling to room temperature to obtain a composite material; and adding the composite material into deionized water, adding an organic coating, uniformly stirring, filtering, drying to remove water, and sieving with a 100-mesh sieve to obtain the composite microcapsule phosphorus flame retardant powder material. The designed organic coating layer solves the problem that the red phosphorus flame retardant is easy to oxidize in the air and the problem of moisture absorption; meanwhile, the designed organic coating layer has good organic compatibility, and the processability is good when the organic coating layer is mixed with engineering plastic or rubber.

Description

Technical Field

[0001] The invention belongs to the technical field of modified preparation of halogen-free flame retardants, and specifically relates to a method for preparing an organic-inorganic composite microcapsule phosphorus-based flame retardant with high whiteness. Background Art

[0002] Red phosphorus (RP) is widely used in rubber and engineering plastics as an excellent flame retardant. It has the characteristics of low addition amount, high flame retardant efficiency, smoke suppression, and low toxicity. However, red phosphorus flame retardant also has some significant disadvantages, which limit its expanded application. For example, red phosphorus is easily oxidized in the air, and it is very easy to absorb moisture after oxidation; in addition, when stored in large quantities, friction and other accidents may cause internal high heat, leading to spontaneous combustion and other fire accidents. In addition, the original color of red phosphorus particles is red, and adding them to plastics or rubber will affect the color of the original material. The industry has carried out surface modification treatment for the above-mentioned problems of red phosphorus. The most commonly used method is microcapsule coating. Using inorganic oxides or hydroxides such as nano-scale inorganic aluminum hydroxide, magnesium hydroxide, titanium dioxide, etc. as coatings can obtain red phosphorus flame retardant powder with a certain whiteness in appearance, but this coating method is often not complete, and the exposed surface still has the problem of oxidation and moisture absorption. At the same time, since the coating is an inorganic substance, it is not compatible with organic substances such as plastics or rubber, and it is not easy to mix evenly; there are also organic coatings, such as melamine formaldehyde resin coating, but this coating method is difficult to change the true color of red phosphorus. These problems limit the use of red phosphorus as a flame retardant. There are also organic / inorganic composite technical solutions that combine the above two methods, but this solution requires the use of red phosphorus powder with very uniform particle size as raw material, otherwise it is also difficult to achieve a uniform coating effect, and the production process of this red phosphorus powder with uniform particle size usually requires grinding the coarse red phosphorus particles in water, and a large amount of phosphorus-containing fine powder wastewater is often generated during the production process, and there are many environmental protection treatment problems. Summary of the invention

[0003] The purpose of the present invention is to solve the problems of existing red phosphorus flame retardants such as easy oxidation, moisture absorption and ignition, and to provide a method for preparing a composite microcapsule phosphorus flame retardant with high oxidation resistance, good hydrophobicity, good compatibility with organic matter and high whiteness.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0005] A method for preparing an organic-inorganic composite microcapsule phosphorus flame retardant with high whiteness, the method comprising:

[0006] (1) Selecting an inorganic oxide with a developed microporous structure and white color as a carrier material;

[0007] (2) placing the carrier material and the phosphorus element in a sealed container, wherein the phosphorus element raw material and the carrier material are placed separately but in the same sealed container;

[0008] (3) placing the sealed container in a high-temperature furnace for heat treatment, so that the phosphorus element sublimates, the phosphorus vapor is adsorbed by the carrier material during the heating process, and the mixture is cooled to room temperature to obtain a composite material;

[0009] (4) The composite material is added to deionized water and an organic coating, stirred evenly, filtered, and then placed in a vacuum drying oven to fully dry and remove water, and then sieved through a 100-mesh sieve to obtain an organic-inorganic composite microcapsule phosphorus flame retardant powder material with a particle size of micrometers.

[0010] Furthermore, in step (1), the carrier material is one or more of SiO2, MgO, Al2O3, TiO2 or ZnO.

[0011] Furthermore, in step (1), the BET of the carrier material is between 500 and 2000 m 2 / g; and the proportion of 0.5-50nm in the total pore volume is >30%.

[0012] Furthermore, in step (1), the particle size distribution of the carrier material requires that the median particle size D50 is between 2-50 μm, D90<100 μm, and D10>0.2 μm.

[0013] Furthermore, in step (2), the phosphorus element is white phosphorus and / or red phosphorus; and the loading environment is an inert atmosphere or a vacuum atmosphere.

[0014] Furthermore, in step (3), the heat treatment temperature is divided into two processes, the first process is 420-650°C for 5-72 hours, and the second process is 260-400°C for 10-48 hours. The second process is mainly to convert all phosphorus vapor into red phosphorus.

[0015] Furthermore, in step (4), the organic coating is one or more of stearic acid, stearate, epoxy resin or organosiloxane.

[0016] Furthermore, in step (4), the mass ratio of the organic coating to the composite material is 0.1 to 1:1.

[0017] Furthermore, in step (4), the vacuum drying conditions are: vacuum degree -0.1Mpa, temperature above 80°C, and drying time above 4h.

[0018] Compared with the existing red phosphorus and red phosphorus microcapsule flame retardant, the present invention has the following advantages:

[0019] 1. The organic-inorganic composite phosphorus flame retardant material of the present invention uses SiO2, Al2O3, MgO, TiO2 or ZnO with a developed microporous structure as a carrier, the body color is white, the phosphorus element is encapsulated in its microporous channels in the form of nanoparticles, the organic coating layer is also white or colorless, and the color of the final material is still white. When mixed with various engineering plastics or rubbers, there is no problem of affecting the body color of the plastics or rubbers.

[0020] 2. The organic-inorganic composite phosphorus flame retardant material of the present invention uses SiO2, Al2O3, TiO2, MgO, and ZnO as carriers. These carriers themselves are also non-combustible. When added to plastics or rubber, they not only play an auxiliary flame retardant effect, but also enhance the mechanical strength of plastic or rubber products.

[0021] 3. The organic-inorganic composite phosphorus flame retardant material of the present invention has a designed organic coating layer, which can effectively solve the problem that the red phosphorus flame retardant is easily oxidized in the air and has a moisture absorption problem; at the same time, the designed organic coating layer has good organic compatibility and good processing performance when mixed with engineering plastics or rubber.

[0022] 4. The organic-inorganic composite phosphorus flame retardant material of the present invention has a particle size of micrometer level, good fluidity and dispersibility, and has good processing performance when mixed with various engineering plastics or rubbers.

[0023] 5. The organic-inorganic composite phosphorus flame retardant material of the present invention uses a sublimation condensation adsorption method as the phosphorus raw material, so there is no need to grind the red phosphorus raw material, and even blocky red phosphorus raw materials can be used. There is no need to dispose of a large amount of waste water generated during the red phosphorus grinding process, which is energy-saving and environmentally friendly, and white phosphorus can also be directly used as a raw material. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the structural principle diagram of the organic-inorganic composite phosphorus flame retardant material;

[0025] Figure 2 To prepare a flow chart;

[0026] Figure 3 This is a diagram showing the hydrophobic effect of organic-inorganic composite phosphorus flame retardant materials;

[0027] Figure 4 This is a test chart of the stability of organic-inorganic composite phosphorus flame retardant materials in air. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention that does not depart from the spirit and scope of the technical solution of the present invention should be included in the protection scope of the present invention.

[0029] Example 1

[0030] Select BET as 800m 2 / g, 50g of SiO2 powder with a pore volume of 50% in the range of 0.5-50nm and a D50 of 5um, and 40g of red phosphorus powder are placed in a stainless steel container, and the two materials are placed in parallel and at intervals; the container is sealed in an operating box filled with argon, and then the sealed container is placed in a high-temperature furnace, heated at 520℃ and kept warm for 8h, then cooled to 400℃ and kept warm for 12h, cooled to room temperature, and 80g of composite material is obtained, and the phosphorus content is quantitatively determined by an elemental analysis instrument to be 37.5%. The 80g composite material is put into a flask containing 300ml of deionized water, vigorously stirred for 5min, and 100g of epoxy resin aqueous solution with a solid content of 15% is slowly added. After continuing to stir for 30min, vacuum filtration is used for solid-liquid separation, and the filter powder is collected and placed in a vacuum oven, and vacuum dried at 100℃ for 12h to obtain a white organic-inorganic composite phosphorus flame retardant powder material.

[0031] After drying, a few water drops were added to the surface of the powder material. The water drops showed a good dew effect on the surface of the material, indicating that the surface of the material has a good hydrophobic effect ( Figure 3 ).

[0032] Example 2

[0033] Select BET as 1000m 2 / g, 0.5-50nm pore volume accounting for 55%, D50 of 6um, 30g of Al2O3 and SiO2 powders respectively, and 60g of red phosphorus powder are put into a stainless steel container, and the Al2O3 and SiO2 powders are mixed together, and they are placed parallel to the red phosphorus powder and at intervals; the container is sealed in an argon-filled operating box, and then the sealed container is placed in a high-temperature furnace, heated at 500°C and kept warm for 10h, then cooled to 350°C and kept warm for 20h, and cooled to room temperature to obtain 108g of a composite material. The phosphorus content of the composite material is quantitatively determined by an elemental analyzer to be 44.4%. Put the 108g composite material into a flask containing 500ml of deionized water, stir vigorously for 10min, slowly add 200g of magnesium stearate emulsified solution with a solid content of 10%, continue stirring for 30min, use vacuum filtration to separate the solid and liquid, collect the filtered powder, put it into a vacuum oven, and vacuum dry it at 100°C for 12h to obtain a white organic-inorganic composite phosphorus flame retardant powder material.

[0034] Example 3

[0035] Select BET as 1200m 2 25g of MgO and SiO2 powders, each with a pore volume of 45% in the range of 0.5-50nm and a D50 of 7um, are put into a stainless steel container together with 50g of white phosphorus under an inert atmosphere. The MgO and SiO2 powders are mixed together and placed parallel to the white phosphorus and at intervals; the container is sealed in an argon-filled operating box, and then the sealed container is placed in a high-temperature furnace, heated at 510°C and kept warm for 15h, then cooled to 270°C and kept warm for 30h, and cooled to room temperature to obtain 92g of a composite material. The phosphorus content of the composite material is quantitatively determined to be 45.6% by an elemental analyzer. The 92 g composite material was put into a flask containing 300 ml of deionized water and stirred vigorously for 8 min. 140 g of an epoxy resin aqueous solution with a solid content of 12% was slowly added. After stirring for 40 min, vacuum filtration was used for solid-liquid separation. The filtered powder was collected and placed in a vacuum oven and vacuum dried at 100°C for 12 h to obtain a white organic-inorganic composite phosphorus flame retardant powder material.

[0036] The organic-inorganic composite phosphorus flame retardant powder material obtained in Examples 1 to 3 was placed in a constant temperature and humidity chamber (T = 25 degrees, RE = 80%) together with ordinary red phosphorus powder. The mass change was measured at intervals and plotted. Figure 4 ,from Figure 4 It can be seen that the organic-inorganic composite phosphorus flame retardant powder material has good quality stability, indicating that it has good antioxidant and hygroscopic properties; while the ordinary red phosphorus powder of the comparison sample has a more obvious weight increase with the shelf time.

Claims

1. A method for preparing an organic-inorganic composite microcapsule phosphorus flame retardant with high whiteness, characterized in that: The method is: (1) Selecting an inorganic oxide with a developed microporous structure and white color as a carrier material; (2) placing the carrier material and the phosphorus element in a sealed container, wherein the phosphorus element raw material and the carrier material are placed separately but in the same sealed container; (3) placing the sealed container in a high-temperature furnace for heat treatment, so that the phosphorus element sublimates, the phosphorus vapor is adsorbed by the carrier material during the heating process, and the mixture is cooled to room temperature to obtain a composite material; (4) The composite material is added into deionized water and an organic coating, stirred evenly, filtered, dried to remove water, and passed through a 100-mesh sieve to obtain a composite microcapsule phosphorus-based flame retardant.

2. The method for preparing an organic-inorganic composite microcapsule phosphorus flame retardant with high whiteness according to claim 1, characterized in that: In step (1), the carrier material is one or more of SiO2, MgO, Al2O3, TiO2 or ZnO.

3. The method for preparing an organic-inorganic composite microcapsule phosphorus flame retardant with high whiteness according to claim 1, characterized in that: In step (1), the BET of the carrier material is between 500 and 2000 m 2 / g; and the proportion of 0.5-50nm in the total pore volume is >30%.

4. The method for preparing an organic-inorganic composite microcapsule phosphorus flame retardant with high whiteness according to claim 1, characterized in that: In step (1), the particle size distribution of the carrier material requires that the median particle size D50 is between 2-50 μm, D90 is less than 100 μm, and D10 is greater than 0.2 μm.

5. The method for preparing an organic-inorganic composite microcapsule phosphorus flame retardant with high whiteness according to claim 1, characterized in that: In step (2), the phosphorus element is white phosphorus and / or red phosphorus; and the loading environment is an inert atmosphere or a vacuum atmosphere.

6. The method for preparing an organic-inorganic composite microcapsule phosphorus flame retardant with high whiteness according to claim 1, characterized in that: In step (3), the heat treatment temperature is divided into two processes, the first process is 420-650°C, the time is 5-72h, and the second process is 260-400°C, the time is 10-48h.

7. The method for preparing an organic-inorganic composite microcapsule phosphorus flame retardant with high whiteness according to claim 1, characterized in that: In step (4), the organic coating is one or more of stearic acid, stearate, epoxy resin or organosiloxane.

8. The method for preparing an organic-inorganic composite microcapsule phosphorus flame retardant with high whiteness according to claim 1, characterized in that: In step (4), the mass ratio of the organic coating to the composite material is 0.1 to 1:

1.

9. The method for preparing the organic-inorganic composite phosphorus-based flame retardant with high whiteness according to claim 1 Preparation method, characterized in that: In step (4), the vacuum drying conditions are: vacuum degree -0.1Mpa, temperature above 80°C, The drying time is more than 4 hours.

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