CN110894369A

CN110894369A - Flame retardant based on phosphaphenanthrene group modified zirconium phosphate and preparation method thereof

Info

Publication number: CN110894369A
Application number: CN201911052505.1A
Authority: CN
Inventors: 刘治田; 王成; 张旗
Original assignee: Wuhan Institute of Technology
Current assignee: Wuhan Institute of Technology
Priority date: 2019-10-31
Filing date: 2019-10-31
Publication date: 2020-03-20

Abstract

The invention discloses a flame retardant based on phosphaphenanthrene group modified zirconium phosphate, which comprises the steps of firstly utilizing tetrabutylammonium hydroxide and phosphoric acid to strip zirconium phosphate to expose hydroxyl groups between zirconium phosphate layers, then utilizing a silane coupling agent to graft zirconium phosphate, and then utilizing benzaldehyde and DOPO to modify stripped zirconium phosphate nano-sheets; the obtained flame retardant product quickly forms carbon on the surface while zirconium phosphate plays a flame retardant role on the base material, so that gaps between the sheet layers are filled, a large number of micro-nano carbon cages are formed, a large number of base material degradation products are sealed in the micro-nano carbon cages, and the zirconium phosphate is sufficiently catalyzed and carbonized in a high-temperature oxygen-deficient environment; meanwhile, free radicals of DOPO can be captured and acted in the microscopic carbon cages to play a role of flame retardance on the microscopic structure level. The flame retardant provided by the invention integrates flame retardant, smoke suppression and enhancement functions, is low in halogen-free cost, good in char formation, environment-friendly and wide in applicability, and the related preparation method is simple in process and suitable for popularization and application.

Description

Flame retardant based on phosphaphenanthrene group modified zirconium phosphate and preparation method thereof

Technical Field

The invention belongs to the technical field of novel flame-retardant smoke-suppressing additives, relates to a novel organic and inorganic hybrid flame-retardant smoke-suppressing additive, and particularly relates to a flame retardant based on phosphaphenanthrene group modified zirconium phosphate and a preparation method thereof.

Background

The polymer/layered nano inorganic composite material has a structure (such as a layered controllable structure) which is not available in the conventional composite materials and has more excellent performance, and has attracted more and more attention of researchers in recent years. The maximum use amount of the inorganic nano powder modified polymer is a hotspot of research in the field of new materials at present. The special structure of the nano material determines special properties (such as small-size effect, macroscopic tunnel effect and the like), and can provide a good method for improving the thermal stability, fire resistance, flame retardance and mechanical properties of the polymer material.

ZrP is an artificially synthesized layered solid acid, has excellent thermal stability, chemical stability and strong acid and strong alkali resistance, has the ion exchange capacity 6 times of clay, has the characteristics of controllable length-diameter ratio, narrow particle size distribution and the like, and is one of excellent matrixes for preparing the polymer layered nano composite material. The ZrP layers are superposed by hydrogen bonding and Van der Waals force, and the HP04 of the ZrP layers^2-H in the radical⁺The interlayer space has larger free activity, the intercalation and exfoliation reaction is easier compared with MMT, and the interlayer crystal water molecules can be replaced by other polar organic molecules. Although ZrP has a layered barrier effect and a solid acid catalytic carbonization effect, the flame retardance of the flame retardant can be obviously improved, the zirconium phosphate cannot be fully stripped by the method reported at present, so that a carbon layer of a flame retardant system is loose, the catalytic carbonization effect time is short, the effect of catalyzing polymer carbonization by zirconium phosphate is limited, and the problems of poor thermal stability, low flame retardant efficiency and the like of the flame retardant are caused.

The problem that the flame retardant efficiency is low and the like caused by the fact that zirconium phosphate can not efficiently catalyze polymers to form carbon is solved; in the patent CN108203519A, methylamine intercalated zirconium phosphate is stripped into lamellar zirconium phosphate after mechanical ball milling, meanwhile, nano lamellar zirconium phosphate is added in the synthesis process of a macromolecular flame retardant MCA, and zirconium phosphate is used as a synergist modified flame retardant and applied to a PA6 flame-retardant composite material, but in the patent, only zirconium phosphate is used as a synergist and only aims at a PA6 material, and the problems of large compounding amount, limited application field, low flame-retardant efficiency and the like exist. In patent CN109810545A, zirconium phosphate is stripped into nanosheets and added into a flame-retardant system, and the carbonization effect of a polymer is improved through the catalytic effect of the zirconium phosphate nanosheets, so that the flame-retardant efficiency is improved.

Therefore, the modification means and the performance of the zirconium phosphate compound are further optimized, so that the method has great research and application significance.

Disclosure of Invention

The invention mainly aims to solve the problems of poor char quality, low loose strength of a char layer, low flame retardant efficiency and the like of the existing flame retardant, and provides a flame retardant based on phosphaphenanthrene group modified zirconium phosphate, wherein benzaldehyde and DOPO are used for modifying stripped zirconium phosphate nanosheets to synthesize a flame retardant based on phosphaphenanthrene group modified zirconium phosphate, and a silane coupling agent is used for grafting benzaldehyde so that flame retardant molecules have a P-O-C-N flame retardant synergistic effect; the flame retardant integrates flame retardant, smoke suppression and enhancement functions, and has the advantages of low cost, good halogen-free char formation, environmental protection, wide applicability, simple preparation method and process, and suitability for popularization and application.

In order to achieve the purpose, the invention adopts the technical scheme that:

a preparation method of a flame retardant based on phosphaphenanthrene group modified zirconium phosphate comprises the following steps:

1) TBA-debonded zirconium phosphate (ZrP): ultrasonically dispersing zirconium phosphate in water under the stirring condition, then dropwise adding a tetrabutylammonium hydroxide solution, ultrasonically stirring for reaction after dropwise adding, dropwise adding concentrated phosphoric acid into the obtained reaction system, and carrying out solid-liquid separation after the reaction is finished for 2 hours to obtain a semitransparent gel precipitate and washing (washing dioxane, removing water from the system);

2) grafting silane coupling agent: adding a silane coupling agent and a reaction solvent into the washed semitransparent gel precipitate, fully dispersing under the action of mechanical stirring and ultrasonic waves, transferring the mixture into an oil pot, and carrying out stirring reaction under the condition of oil bath;

3) graft benzaldehyde and DOPO (9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide): adding benzaldehyde into the reaction product obtained in the step 2) for reaction; and adding DOPO, heating for reflux reaction, cooling to room temperature after the reaction is finished, filtering, washing (washing for 2-3 times by using an acetone aqueous solution (the volume ratio is 1:1) and washing for 2-3 times by using absolute ethyl alcohol), and drying to obtain the flame retardant based on the phosphaphenanthrene group modified zirconium phosphate.

In the scheme, the molar ratio of the zirconium phosphate to the tetrabutylammonium hydroxide to the silane coupling agent is 1 (1-1.5) to 1-1.5; the molar ratio of the zirconium phosphate to the benzaldehyde to the DOPO is 1 (1-3) to 1-3.

In the scheme, the zirconium phosphate is α -zirconium phosphate.

In the scheme, the reaction temperature in the step 1) is 0-5 ℃.

In the scheme, the dropping time of the tetrabutylammonium hydroxide solution in the step 1) is 30-90 min; the dropping time of the concentrated phosphoric acid is 30-90 min.

In the scheme, the concentration of the concentrated phosphoric acid in the step 1) is 3-12 mol/L.

In the scheme, the ultrasonic dispersion time in the step 1) is 30-60 min; the reaction time of ultrasonic stirring is 2-6 h.

In the scheme, the silane coupling agent can be one or more of KH550, KH540, KH551 and the like.

In the scheme, the stirring reaction time in the step 2) is 24-36 h.

In the scheme, the reaction solvent in the step 2) is one or more of dioxane, isopropanol, dimethyl sulfoxide, toluene and the like.

In the scheme, the oil bath temperature is 60-110 ℃.

In the scheme, the benzaldehyde is added in the step 3) for reaction for 12-24h, and DOPO is added for heating reflux reaction for 12-24 h.

The flame retardant based on the phosphaphenanthrene group modified zirconium phosphate prepared according to the scheme integrates flame retardant, smoke suppression and enhancement functions, and is halogen-free, low in cost, good in char formation, environment-friendly and wide in applicability.

The principle of the invention is as follows:

1) the TBA is inserted between zirconium phosphate layers to weaken the acting force between the zirconium phosphate layers and separate the zirconium phosphate layers from one another, so that-OH rich in the zirconium phosphate layers is exposed, a thought is provided for the design of a modified macromolecule of zirconium phosphate, a silane coupling agent is used as a bridge designed for the macromolecule, the peeled zirconium phosphate sheets are grafted with benzaldehyde to modify DOPO, the flame retardant is connected through a chemical bond, the problems of molecular migration and precipitation and cracking of the molecular flame retardant can be avoided, and the stability and the water resistance of the flame retardant can be improved.

2) The silane coupling agent is used for grafting benzaldehyde, so that flame retardant molecules have a P-O-C-N flame retardant synergistic effect; meanwhile, the phosphorus flame retardant can play a flame retardant role in a gas phase and a condensed phase, phosphorus remained in the carbon layer can effectively catalyze the matrix in the form of phosphoric acid, and DOPO can generate a free radical scavenger in the gas phase during the flame retardant role to inhibit free radicals playing a chain growth role in a combustion reaction, so that the flame retardant role is played, and macromolecules can also have a P-Si synergistic effect.

3) When the zirconium phosphate plays a flame-retardant role in the base material, the zirconium phosphate can quickly form carbon on the surface, gaps between the sheet layers are filled, a large number of micro-nano carbon cages are formed, a large number of base material degradation products are sealed in the micro-nano carbon cages, and the zirconium phosphate is sufficiently catalyzed and carbonized in a high-temperature oxygen-deficient environment; meanwhile, free radicals of DOPO can be captured and acted in the microscopic carbon cages, and further the flame retardant effect is exerted on the microstructure layer.

The phosphaphenanthrene in the modified functionalized zirconium phosphate can jointly act on a gas phase and a condensed phase, play a free radical quenching effect and a flame-retardant gas dilution effect in the gas phase, play a covering effect in the condensed phase, and can effectively catalyze a carbon forming agent in the coating to generate a carbon reaction, and a carbonized product can improve the strength, the thermal stability and the barrier property of an expanded carbon layer, so that the fireproof performance of the coating can be improved.

Compared with the prior art, the invention has the beneficial effects that:

1) the DOPO is modified by grafting benzaldehyde through the stripped zirconium phosphate sheet layer, and the flame retardant is connected through a chemical bond, so that the problems of molecular migration, precipitation, cracking and the like of the molecular flame retardant can be avoided, and the stability and the water resistance of the flame retardant are improved.

2) The silane coupling agent such as KH550 and the like is used for grafting benzaldehyde, so that flame retardant molecules have a P-O-C-N flame retardant synergistic effect; DOPO can generate a free radical trapping agent in a gas phase during the flame retardant action, and inhibit free radicals playing a role in chain growth in the combustion reaction, thereby playing a flame retardant role, and enabling macromolecules to have a P-Si synergistic effect, thereby obviously improving the flame retardant efficiency of the flame retardant and being beneficial to ensuring the stability of the obtained flame retardant.

3) The flame retardant obtained by the invention has higher flame retardant efficiency, durability and water resistance, excellent comprehensive performance, environmental protection, no pollution, good compatibility with resin, base materials and the like, and can effectively take other properties (chemical stability, no toxicity, no corrosivity on the base materials and the like) of the material into consideration; and the related preparation method is simple and has wide application field.

Drawings

FIG. 1 is a synthetic route to the zirconium phosphate exfoliation modification described in example 1.

FIG. 2 is an XRD spectrum of ZrP, exfoliated ZrP, ZrP-DOPO as described in example 1.

FIG. 3 is an IR spectrum of ZrP and ZrP-DOPO obtained in example 1.

FIG. 4 is a graph showing the back temperature of combustion of the intumescent coatings obtained in application example 1 and comparative examples 1 and 2.

Detailed Description

In order to better understand the present invention, the following examples are further provided to illustrate the present invention, but the present invention is not limited to the following examples.

In the following examples, the preparation method of zirconium phosphate (α -zirconium phosphate) used includes the steps of preparing 100mL of concentrated phosphoric acid with the molar concentration of 3mo1/L, adding the concentrated phosphoric acid into a 250mL three-neck flask, adding 10.00g of zirconium oxychloride (ZrOCl2-8H20), heating to 95 ℃, mechanically stirring for 20min to fully disperse the zirconium oxychloride, stopping stirring, reacting at the reflux temperature for 24H, standing the obtained mixed solution after the reaction is finished, naturally cooling to the normal temperature, pouring out the supernatant, performing centrifugal treatment (10000r/min, 10min) on the milky precipitate at the lower layer for solid-liquid separation, washing the obtained solid product with a proper amount of deionized water, then performing centrifugal treatment, repeating the steps until the pH of the centrifugal clear liquid is greater than 5, drying the washed solid product in an oven at 80 ℃ for 12H, and grinding to obtain white zirconium phosphate powder (the XRD spectrogram of the zirconium phosphate is shown in figure 2).

Example 1

A flame retardant based on phosphaphenanthrene group modified zirconium phosphate relates to a synthetic route shown in figure 1, and the specific preparation method comprises the following steps:

1) TBA stripping zirconium phosphate: in a 500ml four-mouth flask, 3.00g of zirconium phosphate and 300ml of deionized water are fully dispersed by mechanical stirring and ultrasonic action, the process lasts for 30min, the temperature is kept at 5 ℃, then 11ml of TBA (tetrabutyl ammonium hydroxide aqueous solution, 25 wt%) is dripped into the four-mouth flask at a constant speed within 30min, the reaction is continued for 2h after dripping is finished, 15ml of 4mol/L concentrated phosphoric acid is dripped into the flask at a constant speed within 30min, and after the reaction is finished (2h), the mixed solution is subjected to solid-liquid separation by centrifugation to obtain semitransparent gel precipitate and washed by dioxane;

2) grafted silane coupling agent KH 550: adding the translucent gel washed in the step 1) into a four-neck flask, adding 2.21g of KH550 and 300ml of dioxane, fully dispersing the gel by mechanical stirring and ultrasonic action, then transferring the gel into an oil pan, setting the reaction temperature to 90 ℃, and mechanically stirring for 24 hours to obtain peeled ZrP (an XRD spectrogram is shown in figure 2);

3) graft benzaldehyde and DOPO: adding 1.06g of benzaldehyde into the mixed solution obtained in the step 2), reacting for 12h, adding 2.16g of DOPO into a device, heating to reflux for 12h (at 105 ℃), cooling to room temperature after the reaction is finished, filtering to obtain a crude product, washing for 2-3 times by using a mixed solution of acetone and deionized water (volume ratio of 1:1), washing for 2-3 times by using absolute ethyl alcohol, and finally drying for 24h in a vacuum drying oven to obtain a final product (ZrP-DOPO).

The XRD patterns of ZrP and ZrP-DOPO obtained in this example are shown in FIG. 2, and it can be seen that: ZrP has strong diffraction peaks at 11.64 degrees, 19.74 degrees and 24.90 degrees of 2 theta respectively, and the strong diffraction peaks are respectively assigned to (002), (110) and (112) crystal faces of the ZrP crystal; (002) the XRD spectrum peak of the crystal face reflects the interlayer information of the ZrP crystal, and the interlayer spacing of the ZrP crystal can be calculated to be 0.76nm according to the Bragg equation; after TBA intercalation treatment, the (110) and (112) peaks disappear, and only a very weak (002) peak appears at the 2 theta of 6.86 degrees, which indicates that most ZrP is successfully stripped by TBA and a small amount of ZrP is in an intercalation state; on the XRD spectrogram of ZrP-DOPO, all main diffraction peaks almost disappear, which shows that the ZrP can be thoroughly peeled into a single layer by the flame-retardant modified ZrP, and the layers are in a disordered distribution state.

The IR spectra of ZrP and ZrP-DOPO obtained in this example are shown in FIG. 3, and the results show that: the main characteristic absorption peaks of ZrP are as follows: vibration absorption peak (3595 cm) of ZrP interlaminar crystal water^-1And 3510cm^-1) Symmetric stretching vibration and bending vibration peak of-OH (3155 cm)^-1And 1617cm^-1) Symmetric and asymmetric P-O stretching vibration peak (1120 cm)^-1And 1042cm^-1) And vibration absorption peak of Zr-O (593 cm)^-1And 533cm^-1) (ii) a Main absorption peak of ZrP-DOPO of the final product: the peak of the N-H stretching vibration and bending vibration is (3422 cm)^-1And 1635cm^-1)，(3595cm^-1，3510cm^-1) Disappearance proves that the vibration absorption peak of the ZrP interlaminar crystal water disappears, which indicates that the ZrP is successfully stripped in the synthesis process, 3064cm^-1，1403cm^-1The peak of C-H stretching vibration and bending vibration. 1467cm^-1The characteristic peak of P-H on the phosphaphenanthrene group disappears to prove that DOPO is grafted successfully.

Example 2

A flame retardant based on phosphaphenanthrene group modified zirconium phosphate is prepared by the following steps:

1) TBA stripping zirconium phosphate: in a 500ml four-mouth flask, 6.00 ml zirconium phosphate and 300ml deionized water are fully dispersed by mechanical stirring and ultrasonic action, the process lasts for 30min, the temperature is kept at 5 ℃, then 32ml TBA (tetrabutyl ammonium hydroxide 25 wt% aqueous solution) is dripped into the four-mouth flask at a constant speed within 30min, the reaction is continued for 2h after dripping, 15ml 4mol/L concentrated phosphoric acid is dripped into the flask at a constant speed within 30min, after the reaction is finished, the mixed solution is subjected to solid-liquid separation by centrifugation to obtain semitransparent gel precipitate and is washed by dioxane;

2) grafted silane coupling agent KH 550: adding the washed translucent gel into a four-neck flask, adding 4.43gKH550 and 150ml dioxane, fully dispersing the gel by mechanical stirring and ultrasonic action, then transferring the gel into an oil pan, setting the reaction temperature at 90 ℃, and mechanically stirring for 24 hours;

3) graft benzaldehyde and DOPO: adding 4.24g of benzaldehyde into the mixed solution in the step 2) to react for 12 hours; adding 8.66g of DOPO into the device, heating to reflux (the temperature is 105 ℃), reacting for 12h, cooling to room temperature after the reaction is finished, filtering to obtain a crude product, washing for 2-3 times by using a mixed solution (1:1) of acetone and deionized water, washing for 2-3 times by using absolute ethyl alcohol, and finally drying for 24h in a vacuum drying oven to obtain the final product.

Example 3

1) TBA stripping zirconium phosphate: in a 500ml four-mouth flask, 1.00g of zirconium phosphate and 150ml of deionized water are fully dispersed by mechanical stirring and ultrasonic action, the process lasts for 30min, the temperature is kept at 5 ℃, then 4ml of TBA (tetrabutylammonium hydroxide 25 wt% aqueous solution) is dripped into the four-mouth flask at a constant speed within 30min, the reaction is continued for 2h after dripping, 15ml of 4mol/L concentrated phosphoric acid is dripped into the flask at a constant speed within 30min, and after the reaction is finished (2h), the mixed solution is subjected to solid-liquid separation by centrifugation to obtain semitransparent gel precipitate and is washed by dioxane;

2) grafted silane coupling agent KH 550: adding the washed translucent gel into a four-neck flask, adding 0.74gKH550 and 150ml dioxane, fully dispersing the gel by mechanical stirring and ultrasonic action, then transferring the gel into an oil pan, setting the reaction temperature at 90 ℃, and mechanically stirring for 24 hours;

3) graft benzaldehyde and DOPO: adding 0.53g of benzaldehyde into the mixed solution obtained in the step 2), reacting for 12h, adding 2.16g of DOPO into a device, heating to reflux (the temperature is 105 ℃), reacting for 12h, cooling to room temperature after the reaction is finished, filtering to obtain a crude product, washing for 2-3 times by using a mixed solution (1:1) of acetone and deionized water, washing for 2-3 times by using absolute ethyl alcohol, and finally drying for 24h in a vacuum drying oven to obtain a final product.

Application example 1

The flame retardant obtained in the embodiment 1 is applied to the preparation of the acrylate-based intumescent fire retardant coating, and the specific steps comprise:

1) weighing the raw materials according to the mixture ratio, wherein the components and the mass percentage thereof comprise: 20% of acrylate emulsion, 36% of ammonium polyphosphate, 12% of pentaerythritol, 12% of melamine, 3% of titanium dioxide, 0.5% of hydroxyethyl cellulose, 0.5% of dispersant, 0.5% of defoamer, 0.5% of n-octanol, 10% of water and 5% of flame retardant based on phosphaphenanthrene group modified zirconium phosphate;

2) grinding the weighed ammonium polyphosphate, pentaerythritol, melamine, titanium dioxide and hydroxyethyl cellulose into powder, and then adding water to fully grind and uniformly mix; adding the defoaming agent and the dispersing agent, and continuously and fully grinding;

3) and finally, adding a flame retardant based on the phosphaphenanthrene group modified zirconium phosphate, acrylate emulsion and n-octanol, fully grinding and uniformly mixing to obtain the fireproof coating.

Application example 2

The preparation method of the fireproof coating in application example 2 is substantially the same as that in application example 1, except that the fireproof coating comprises the following components in percentage by mass: 20% of acrylate emulsion, 36% of ammonium polyphosphate, 12% of pentaerythritol, 12% of melamine, 3% of titanium dioxide, 0.5% of hydroxyethyl cellulose, 0.5% of dispersant, 0.5% of defoamer, 0.5% of n-octanol, 12% of water and 3% of flame retardant based on phosphaphenanthrene group modified zirconium phosphate.

Application example 3

The preparation method of the fireproof coating in application example 3 is substantially the same as that of application example 1, except that: the components and the mass percentage thereof are as follows: 20% of acrylate emulsion, 36% of ammonium polyphosphate, 12% of pentaerythritol, 12% of melamine, 3% of titanium dioxide, 0.5% of hydroxyethyl cellulose, 0.5% of dispersant, 0.5% of defoamer, 0.5% of n-octanol, 13% of water and 2% of flame retardant based on phosphaphenanthrene group modified zirconium phosphate.

Comparative example 1

The preparation method of the fireproof coating in the comparative example 1 is substantially the same as that in the application example 1, except that the fireproof coating comprises the following components in percentage by mass: 20% of acrylate emulsion, 36% of ammonium polyphosphate, 12% of pentaerythritol, 12% of melamine, 3% of titanium dioxide, 0.5% of hydroxyethyl cellulose, 0.5% of dispersant, 0.5% of defoamer, 0.5% of n-octanol and 15% of water.

Comparative example 2

The preparation method of the fireproof coating of comparative example 2 is substantially the same as that of application example 1, except that the fireproof coating comprises 20% of acrylate emulsion, 36% of ammonium polyphosphate, 12% of pentaerythritol, 12% of melamine, 3% of titanium dioxide, 0.5% of hydroxyethyl cellulose, 0.5% of dispersant, 0.5% of defoamer, 0.5% of n-octanol, 10% of water and 5% of zirconium phosphate.

Comparative example 3

The preparation method of the fireproof coating described in comparative example 3 is substantially the same as that of application example 1, except that the fireproof coating comprises 20% of acrylate emulsion, 36% of ammonium polyphosphate, 12% of pentaerythritol, 12% of melamine, 3% of titanium dioxide, 0.5% of hydroxyethyl cellulose, 0.5% of dispersant, 0.5% of defoamer, 0.5% of n-octanol, 10% of water and 5% of DOPO.

Comparative example 4

Comparative example 4 the fire retardant coating material was prepared in the same manner as in application example 1, except that 20% of the acrylate emulsion, 36% of ammonium polyphosphate, 12% of pentaerythritol, 12% of melamine, 3% of titanium dioxide, 0.5% of hydroxyethyl cellulose, 0.5% of a dispersant, 0.5% of a defoaming agent, 0.5% of n-octanol, 10% of water, and 5% by weight of a mixture of zirconium phosphate and DOPO (3% by weight of zirconium phosphate, 2% by weight of DOPO).

The intumescent fire-retardant coatings obtained in application examples 1-3 and comparative examples 1-4 were respectively subjected to fire resistance tests, and the results are shown in table 1.

TABLE 1 relevant Performance test of the intumescent coatings obtained in application examples 1-3 and comparative examples 1-4

The combustion back temperature curve diagrams of the intumescent fire-retardant coatings obtained in application example 1, comparative example 1 and comparative example 2 are shown in figure 4, and the results show that the coatings prepared by using the flame retardant obtained in the invention can exert excellent flame-retardant effect.

The above results show that: the flame retardant disclosed by the invention has the advantages of higher flame retardant efficiency, environmental friendliness, no pollution, good compatibility with resin, base materials and the like, and capability of effectively considering other properties of materials.

The invention can be realized by the upper and lower limit values and interval values of all raw materials, and the invention can be realized by the lower limit values and interval values of the process parameters (such as temperature, time and the like), and the examples are not listed. The above description is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make various modifications and changes without departing from the inventive concept of the present invention, and these modifications and changes are within the protection scope of the present invention. The invention can be realized by all the listed raw materials, and the invention can be realized by the upper and lower limit values and interval values of all the raw materials; the examples are not to be construed as limiting the scope of the invention. The upper and lower limit values and interval values of the process parameters can realize the invention, and the embodiments are not listed.

Claims

1. A preparation method of a flame retardant based on phosphaphenanthrene group modified zirconium phosphate is characterized by comprising the following steps:

1) TBA stripping zirconium phosphate: ultrasonically dispersing zirconium phosphate in water under the stirring condition, then dropwise adding a tetrabutylammonium hydroxide solution, ultrasonically stirring for reaction after the dropwise adding is finished, dropwise adding concentrated phosphoric acid into the obtained reaction system, and carrying out solid-liquid separation after the reaction is finished for 2 hours to obtain a semitransparent gel precipitate and washing;

2) grafting silane coupling agent: adding a silane coupling agent and a reaction solvent into the washed semitransparent gel precipitate, fully dispersing under the action of mechanical stirring and ultrasonic waves, and then carrying out stirring reaction under the condition of oil bath;

3) graft benzaldehyde and DOPO (9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide): adding benzaldehyde into the reaction product obtained in the step 2) for reaction; and adding DOPO, heating for reflux reaction, cooling to room temperature after the reaction is finished, filtering, washing and drying to obtain the flame retardant based on the phosphaphenanthrene group modified zirconium phosphate.

2. The method according to claim 1, wherein the molar ratio of the zirconium phosphate to the tetrabutylammonium hydroxide to the silane coupling agent is 1 (1-1.5) to 1-1.5; the molar ratio of the zirconium phosphate to the benzaldehyde to the DOPO is 1 (1-3) to 1-3.

3. The method according to claim 1, wherein the reaction temperature in step 1) is 0 to 5 ℃.

4. The method according to claim 1, wherein the tetrabutylammonium hydroxide solution is added dropwise for 30-90min in step 1); the dropping time of the concentrated phosphoric acid is 30-90 min.

5. The method according to claim 1, wherein the concentration of the concentrated phosphoric acid in the step 1) is 3 to 12 mol/L.

6. The method according to claim 1, wherein the ultrasonic dispersion time in step 1) is 30-60 min; the reaction time of ultrasonic stirring is 2-6 h.

7. The preparation method according to claim 1, wherein the silane coupling agent is one or more selected from the group consisting of KH550, KH540, and KH 551.

8. The preparation method according to claim 1, wherein the stirring reaction time in the step 2) is 24 to 36 hours.

9. The preparation method according to claim 1, wherein the benzaldehyde is added in the step 3) for 12 to 24 hours, and DOPO is added for heating and refluxing for 12 to 24 hours.

10. The flame retardant based on the phosphaphenanthrene group modified zirconium phosphate prepared by the preparation method of any one of claims 1 to 9.