阅读说明：本技术 一种无机阻燃剂及其制备方法和在制备密封胶中的应用 (Inorganic flame retardant, preparation method thereof and application thereof in preparing sealant ) 是由 邓娇容 于 2021-01-05 设计创作，主要内容包括：本发明适用于材料技术领域,提供了一种无机阻燃剂及其制备方法和在密封胶中的应用,该方法通过将将超疏水改性处理后的蒙脱土分散在聚合磷酸盐溶液中,再升温至40℃～50℃后加入硼酸饱和溶液,搅拌反应得到混合液；再将得到的混合液加入氢氧化铝溶液或氢氧化镁溶液进行包覆反应,得到包覆产物；接着对得到的包覆产物进行过滤、干燥、解聚处理,再经偶联剂进行表面改性处理得到。由本发明的制备方法制得的无机阻燃剂不仅具有优异的阻燃效果,且抑烟性能明显提高；且能够与高分子材料很好地相容,可均匀分散在材料体系中,有利于提高材料的综合性能；在达到相同的阻燃等级,添加量明显少于传统的无机阻燃剂,因而可降低成本。(The invention is suitable for the technical field of materials, and provides an inorganic flame retardant, a preparation method thereof and application thereof in sealant, wherein the method comprises the steps of dispersing montmorillonite subjected to super-hydrophobic modification treatment in a polymeric phosphate solution, heating to 40-50 ℃, adding a boric acid saturated solution, and stirring for reaction to obtain a mixed solution; adding the obtained mixed solution into an aluminum hydroxide solution or a magnesium hydroxide solution for coating reaction to obtain a coated product; and then filtering, drying and depolymerizing the obtained coated product, and carrying out surface modification treatment by using a coupling agent to obtain the coating. The inorganic flame retardant prepared by the preparation method has excellent flame retardant effect and obviously improved smoke suppression performance; the material can be well compatible with high polymer materials, can be uniformly dispersed in a material system, and is beneficial to improving the comprehensive performance of the material; when the same flame-retardant grade is achieved, the addition amount is obviously less than that of the traditional inorganic flame retardant, so that the cost can be reduced.)

1. The preparation method of the inorganic flame retardant is characterized by comprising the following steps:

dispersing montmorillonite subjected to super-hydrophobic modification treatment in a polymeric phosphate solution to obtain montmorillonite dispersion liquid;

heating the montmorillonite dispersion liquid to 40-50 ℃, adding a boric acid saturated solution, and stirring and reacting for 30-60 min to obtain a mixed solution;

adding an aluminum hydroxide solution into the mixed solution and adjusting the pH value of the solution to 9.5-12.5; or adding a magnesium hydroxide solution, adjusting the pH value of the solution to 8.5-11.0, and stirring for reaction for 1-2 hours to obtain a coated product;

and filtering, drying and depolymerizing the coating reaction product, and carrying out surface modification treatment by using a coupling agent to obtain the inorganic flame retardant.

2. The method for preparing the inorganic flame retardant of claim 1, wherein the method for preparing the montmorillonite subjected to the superhydrophobic modification treatment comprises the following steps:

mixing vinyl silicone oil, sodium dodecyl benzene sulfonate and water according to the mass ratio of 10:1:70, adding styrene and tridecafluorooctyl methacrylate, stirring and mixing uniformly, adding montmorillonite, heating to 70-75 ℃ under the protection of nitrogen, adding an initiator, stirring and reacting for 5-7 hours, washing by deionized water, dispersing in ethanol, removing the solvent, and drying to obtain the catalyst.

3. The method for preparing the inorganic flame retardant of claim 2, wherein the mixing mass ratio of the styrene to the tridecyl octyl methacrylate is 5-6: 2.

4. The method of producing an inorganic flame retardant according to claim 2, wherein the initiator is azobisisobutyronitrile or potassium persulfate.

5. The method of preparing the inorganic flame retardant of claim 1, wherein the polymeric phosphate solution is a sodium hexametaphosphate solution having a concentration of 0.1 to 0.2 g/L.

6. The preparation method of the inorganic flame retardant of claim 1, wherein the step of heating the montmorillonite dispersion to 40-50 ℃, adding a boric acid saturated solution, and stirring for reaction for 30-60 min specifically comprises:

and heating the montmorillonite dispersion liquid to 40-50 ℃, adding a boric acid saturated solution, adjusting the pH value to 4.5-5, and stirring for reaction for 30-60 min.

7. The method for producing an inorganic flame retardant according to claim 1, wherein the depolymerization treatment specifically comprises:

and carrying out ball milling on the coated product after filtering and drying treatment to obtain coated product powder, wherein the ball milling time is 5-10 min, the ball-material ratio is 4:1, and the rotating speed is 10-15 Hz.

8. The method of claim 1, wherein the coupling agent is a silane coupling agent or an aluminate coupling agent, and the modification temperature is 100 ℃ to 120 ℃.

9. An inorganic flame retardant, characterized in that the inorganic flame retardant is prepared by the method for preparing the inorganic flame retardant according to any one of claims 1 to 8.

10. Use of the inorganic flame retardant of claim 9 in the preparation of a sealant.

Technical Field

The invention belongs to the technical field of materials, and particularly relates to an inorganic flame retardant, a preparation method thereof and application thereof in preparing a sealant.

Background

The polymer material is visible everywhere in various industries, has a wide application range, and basically covers the fields of traffic, buildings, transportation, communication, aviation, clothing and the like. However, it is known that polymer materials are often flammable, and therefore, in order to improve the flame retardant performance, a certain amount of flame retardant is generally added to the polymer materials.

Currently, mainstream flame retardants include halogen-based flame retardants and halogen-free flame retardants. However, the halogen-based flame retardant is likely to generate a large amount of toxic gas and smoke during combustion and decomposition, which is not only harmful to human health but also environmentally unfriendly, and thus, in recent years, the halogen-based flame retardant is gradually replaced by the halogen-free flame retardant.

Although the existing halogen-free flame retardant has the characteristics of good flame retardance, smoke suppression, low toxicity and the like, the halogen-free flame retardant has poor compatibility with a high polymer material and is difficult to uniformly disperse in a material system, so that the flame retardant effect of the material is reduced, and the mechanical property of the material is also reduced. In addition, the addition amount is large when the catalyst is used, and the cost is high.

Disclosure of Invention

The embodiment of the invention provides a preparation method of an inorganic flame retardant, and aims to provide an inorganic flame retardant which has good flame retardance, smoke suppression and low toxicity, can be well compatible with a high polymer material, can be uniformly dispersed in a material system, and is small in addition amount.

The embodiment of the invention is realized in such a way that the preparation method of the inorganic flame retardant comprises the following steps:

dispersing montmorillonite subjected to super-hydrophobic modification treatment in a polymeric phosphate solution to obtain montmorillonite dispersion liquid;

heating the montmorillonite dispersion liquid to 40-50 ℃, adding a boric acid saturated solution, and stirring and reacting for 30-60 min to obtain a mixed solution;

adding an aluminum hydroxide solution into the mixed solution and adjusting the pH value of the solution to 9.5-12.5; or adding a magnesium hydroxide solution, adjusting the pH value of the solution to 8.5-11.0, and stirring for reaction for 1-2 hours to obtain a coated product;

and filtering, drying and depolymerizing the coating reaction product, and carrying out surface modification treatment by using a coupling agent to obtain the inorganic flame retardant.

The embodiment of the invention also provides an inorganic flame retardant, and the inorganic flame retardant is prepared by the preparation method of the inorganic flame retardant.

The embodiment of the invention also provides the application of the inorganic flame retardant in preparing the sealant.

According to the preparation method of the inorganic flame retardant provided by the embodiment of the invention, the montmorillonite subjected to the super-hydrophobic modification treatment is dispersed in the polymeric phosphate solution, then the temperature is raised to 40-50 ℃, the boric acid saturated solution is added, and the stirring reaction is carried out so that borate ions are inserted into the interlayer structure of the montmorillonite subjected to the super-hydrophobic modification treatment, thereby being beneficial to improving the smoke suppression performance of the inorganic flame retardant; then adding the obtained mixed solution into an aluminum hydroxide solution or a magnesium hydroxide solution for coating reaction to obtain an aluminum hydroxide coated or magnesium hydroxide coated product, which can obviously improve the flame retardant property of the inorganic flame retardant; then, the obtained coating product is filtered, dried and depolymerized, and then is subjected to surface modification treatment by a coupling agent, so that the compatibility of the inorganic flame retardant and a high polymer material and the dispersibility of the inorganic flame retardant in a material system are improved. The inorganic flame retardant prepared by the preparation method provided by the embodiment of the invention has excellent flame retardant effect and obviously improved smoke suppression performance; in addition, the inorganic flame retardant can be well compatible with a high polymer material, can be uniformly dispersed in a material system, and is favorable for improving the mechanical property of the material; when the same flame-retardant grade is achieved, the addition amount is obviously less than that of the traditional inorganic flame retardant, so that the cost can be reduced.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

According to the preparation method of the inorganic flame retardant provided by the embodiment of the invention, montmorillonite subjected to super-hydrophobic modification treatment is dispersed in a polymeric phosphate solution, then a boric acid saturated solution is added, and stirring reaction is carried out so that borate ions are inserted into an interlayer structure of the montmorillonite subjected to super-hydrophobic modification treatment, thereby being beneficial to improving the smoke suppression performance of the inorganic flame retardant; then adding the obtained mixed solution into an aluminum hydroxide solution or a magnesium hydroxide solution for coating reaction to obtain an aluminum hydroxide coated or magnesium hydroxide coated product, which can obviously improve the flame retardant property of the inorganic flame retardant; then, the obtained coating product is filtered, dried and depolymerized, and then is subjected to surface modification treatment by a coupling agent, so that the compatibility of the inorganic flame retardant and a high polymer material and the dispersibility of the inorganic flame retardant in a material system are improved.

The embodiment of the invention provides a preparation method of an inorganic flame retardant, which comprises the following steps:

step 101, dispersing montmorillonite subjected to super-hydrophobic modification treatment in a polymeric phosphate solution to obtain montmorillonite dispersion liquid.

Montmorillonite is a clay mineral formed by stacking nanometer-thickness silicate sheets with negative electricity on the surface by virtue of interlayer electrostatic interaction, and a unit cell in a crystal structure of the montmorillonite is formed by two layers of silicon-oxygen tetrahedrons and a layer of aluminum-oxygen octahedron sandwiched between the two layers of silicon-oxygen tetrahedrons. And has unique one-dimensional layered nano-structure and cation exchange property.

In the embodiment of the invention, the montmorillonite can adopt calcium-based, sodium-calcium-based or magnesium-based montmorillonite. Preferably, sodium-or magnesium-based montmorillonite is used, the average wafer thickness of which is less than 25 nm.

And step 102, heating the montmorillonite dispersion liquid to 40-50 ℃, adding a boric acid saturated solution, and stirring and reacting for 30-60 min to obtain a mixed solution.

In the embodiment of the invention, boric acid saturated solution is added into the montmorillonite dispersion liquid at 40-50 ℃, so that borate ions in the montmorillonite dispersion liquid can be smoothly intercalated between interlayer structures of montmorillonite, and the smoke suppression performance of the inorganic flame retardant is improved.

103, adding an aluminum hydroxide solution into the mixed solution and adjusting the pH value of the solution to 9.5-12.5; or adding a magnesium hydroxide solution, adjusting the pH value of the solution to 8.5-11.0, and stirring for reaction for 1-2 hours to obtain a coated product.

In the embodiment of the invention, aluminum hydroxide or magnesium hydroxide solution is added into the obtained borate intercalation montmorillonite mixed solution, the pH value of the solution is adjusted, and stirring reaction is carried out to obtain an aluminum hydroxide coated product or a magnesium hydroxide coated product, so that the flame retardant property of the inorganic flame retardant can be obviously improved.

And 104, filtering, drying and depolymerizing the coating reaction product, and performing surface modification treatment by using a coupling agent to obtain the inorganic flame retardant.

In the embodiment of the present invention, the preparation method of the montmorillonite subjected to the superhydrophobic modification in step 101 is as follows: mixing vinyl silicone oil, sodium dodecyl benzene sulfonate and water according to a mass ratio of 79:1:536, adding styrene and tridecafluorooctyl methacrylate, stirring and mixing uniformly, adding montmorillonite, heating to 70-75 ℃ under the protection of nitrogen, adding an initiator, stirring and reacting for 5-7 hours, washing with deionized water, dispersing in ethanol, removing the solvent, and drying to obtain the catalyst.

The solvent of the mixed solution of the styrene and the tridecafluorooctyl methacrylate is vinyl silicone oil, sodium dodecyl benzene sulfonate and water which are mixed according to the mass ratio of 10:1:70 to prepare the mixed solution. Wherein the mixing mass ratio of the styrene to the tridecyl octyl methacrylate is 5-6: 2.

The initiator is azodiisobutyronitrile or potassium persulfate.

In the embodiment of the present invention, the polymerized phosphate solution used in the step 101 is a sodium hexametaphosphate solution with a concentration of 0.1-0.2 g/L.

In the embodiment of the invention, the step of heating the montmorillonite dispersion to 40-50 ℃, adding the boric acid saturated solution, and stirring for reaction for 30-60 min specifically comprises the following steps: heating the montmorillonite dispersion liquid to 40-50 ℃, adding a boric acid saturated solution, adjusting the pH value to 4.5-5, and stirring for reaction for 30-60 min.

In an embodiment of the present invention, the depolymerization process in step 104 specifically includes: and carrying out ball milling on the coated product after filtering and drying treatment to obtain coated product powder. In order to avoid excessive ball milling to make the particle size of the coated product too small and increase the dispersion difficulty of the coated product in a material system, the treatment is preferably carried out according to the conditions that the ball milling time is 5-10 min, the ball-to-material ratio is 4:1 and the rotating speed is 10-15 Hz. A large number of experiments prove that the depolymerization treatment is carried out on the coated product under the ball milling time, the ball-to-material ratio and the rotating speed, so that the agglomeration phenomenon of the product can be reduced, the particle size of the product can be controlled within a proper range, and the surface modification treatment of the product by a coupling agent is facilitated, thereby further improving the compatibility and the dispersion performance of the flame retardant and a macromolecule.

In an embodiment of the present invention, the coupling agent used in step 104 is a silane coupling agent or an aluminate coupling agent, and the modification temperature is 100 ℃ to 120 ℃.

In the embodiment of the invention, the silane coupling agent can be any one or more of vinyltriethoxysilane, vinyltrimethoxysilane or vinyltris (beta-methoxyethoxy) silane.

By adopting the coupling agent to carry out surface modification treatment on the depolymerized coating product, the compatibility of the inorganic flame retardant and a high polymer material can be improved, and the dispersibility of the inorganic flame retardant in a material system can be improved, so that the mechanical property of the material can be improved.

The embodiment of the invention also provides an inorganic flame retardant prepared by the preparation method of the inorganic flame retardant. The inorganic flame retardant is prepared by the preparation method, so that the inorganic flame retardant has better compatibility and dispersibility, and the addition amount of the inorganic flame retardant is obviously less than that of the traditional inorganic flame retardant when the same flame retardant effect is required to be achieved, so that the cost is saved.

The inorganic flame retardant can be applied to the preparation of sealant. The inorganic flame retardant has good compatibility and dispersibility, can be well compatible with a high polymer material, is well dispersed in a material system, has small filling addition amount, is not easy to cause the material system to generate a phenomenon of 'half-cooked', not only can enable the material to have good flame retardant property and smoke suppression property, but also is beneficial to improving the mechanical property of the material.

Examples of certain embodiments of the invention are given below, which are not intended to limit the scope of the invention.

Example 1

The preparation steps of the inorganic flame retardant of the embodiment are as follows:

adding 100mL of vinyl silicone oil, 1.02g of sodium dodecyl benzene sulfonate and 700mL of water into a flask with a mechanical stirring device, uniformly stirring and mixing, adding 501g of styrene and 200g of tridecafluorooctyl methacrylate, continuously uniformly stirring, adding 300.1g of montmorillonite, heating to 75 ℃ under the protection of nitrogen, adding 0.03g of azobisisobutyronitrile to initiate reaction, stirring and reacting for 5 hours, washing for 3 times by deionized water, dispersing in ethanol, treating at 55 ℃ for 20min to remove a solvent, and drying to obtain the montmorillonite subjected to super-hydrophobic modification treatment. And dispersing the montmorillonite subjected to the super-hydrophobic modification treatment in a sodium hexametaphosphate solution with the concentration of 0.1g/L to obtain montmorillonite dispersion liquid. Heating the montmorillonite dispersion liquid to 40 ℃, adding a boric acid saturated solution, adjusting the pH value to 4.5, and stirring for reaction for 30min to obtain a mixed solution. And adding an aluminum hydroxide solution into the mixed solution, adjusting the pH value of the solution to 10.5, and stirring for reaction for 1 hour to obtain a coating product. And filtering and drying the coating reaction product, performing ball milling and crushing treatment for 5min under the conditions that the ball-material ratio is 4:1 and the rotating speed is 10Hz to obtain coating product powder, and performing surface modification treatment on the coating product powder by using an aluminate coupling agent at the modification temperature of 100 ℃ to obtain the inorganic flame retardant.

Example 2

The preparation steps of the inorganic flame retardant of the embodiment are as follows:

adding 100mL of vinyl silicone oil, 1.01g of sodium dodecyl benzene sulfonate and 700mL of water into a flask with a mechanical stirring device, uniformly stirring and mixing, adding 600g of styrene and 200g of tridecafluorooctyl methacrylate, continuously uniformly stirring, adding 300.5g of montmorillonite, heating to 70 ℃ under the protection of nitrogen, adding 0.025g of azobisisobutyronitrile to initiate reaction, stirring and reacting for 7 hours, washing for 3 times by deionized water, dispersing in ethanol, treating at 60 ℃ for 20min to remove the solvent, and drying to obtain the montmorillonite subjected to super-hydrophobic modification treatment. And dispersing the montmorillonite subjected to the super-hydrophobic modification treatment in a sodium hexametaphosphate solution with the concentration of 0.2g/L to obtain montmorillonite dispersion liquid. And heating the montmorillonite dispersion liquid to 40 ℃, adding a boric acid saturated solution, adjusting the pH value to 5, and stirring for reacting for 60min to obtain a mixed liquid. And adding a magnesium hydroxide solution into the mixed solution, adjusting the pH value of the solution to 10.5, and stirring for reaction for 1 hour to obtain a coating product. And filtering and drying the coating reaction product, then carrying out ball milling and crushing treatment for 5min under the conditions that the ball-material ratio is 4:1 and the rotating speed is 15Hz to obtain coating product powder, and then carrying out surface modification treatment on the coating product powder by using an aluminate coupling agent at the modification temperature of 110 ℃ to obtain the inorganic flame retardant.

Example 3

The preparation steps of the inorganic flame retardant of the embodiment are as follows:

adding 100mL of vinyl silicone oil, 1.02g of sodium dodecyl benzene sulfonate and 700mL of water into a flask with a mechanical stirring device, uniformly stirring and mixing, adding 550g of styrene and 200g of tridecafluorooctyl methacrylate, continuously uniformly stirring, adding 300.1g of montmorillonite, heating to 75 ℃ under the protection of nitrogen, adding 0.03g of azobisisobutyronitrile to initiate reaction, stirring and reacting for 6 hours, washing for 3 times by deionized water, dispersing in ethanol, treating at 60 ℃ for 20min to remove a solvent, and drying to obtain the montmorillonite subjected to super-hydrophobic modification treatment. And dispersing the montmorillonite subjected to the super-hydrophobic modification treatment in a sodium hexametaphosphate solution with the concentration of 0.15g/L to obtain montmorillonite dispersion liquid. Heating the montmorillonite dispersion liquid to 50 ℃, adding a boric acid saturated solution, adjusting the pH value to 4.5, and stirring for reaction for 30min to obtain a mixed solution. And adding an aluminum hydroxide solution into the mixed solution, adjusting the pH value of the solution to 9.5, and stirring for reaction for 1.5 hours to obtain a coating product. And filtering and drying the coating reaction product, performing ball milling and crushing treatment for 8min under the conditions that the ball-material ratio is 4:1 and the rotating speed is 12Hz to obtain coating product powder, and performing surface modification treatment on the coating product powder by using an aluminate coupling agent at the modification temperature of 120 ℃ to obtain the inorganic flame retardant.

Example 4

The preparation steps of the inorganic flame retardant of the embodiment are as follows:

adding 100mL of vinyl silicone oil, 1.01g of sodium dodecyl benzene sulfonate and 700mL of water into a flask with a mechanical stirring device, uniformly stirring and mixing, adding 580g of styrene and 200g of tridecafluorooctyl methacrylate, continuously uniformly stirring, adding 300.1g of montmorillonite, heating to 75 ℃ under the protection of nitrogen, adding 0.03g of azobisisobutyronitrile to initiate reaction, stirring and reacting for 5 hours, washing for 3 times by deionized water, dispersing in ethanol, treating at 60 ℃ for 20min to remove the solvent, and drying to obtain the montmorillonite subjected to super-hydrophobic modification treatment. And dispersing the montmorillonite subjected to the super-hydrophobic modification treatment in a sodium hexametaphosphate solution with the concentration of 0.2g/L to obtain montmorillonite dispersion liquid. Heating the montmorillonite dispersion liquid to 50 ℃, adding a boric acid saturated solution, adjusting the pH value to 4.5, and stirring for reacting for 60min to obtain a mixed solution. And adding a magnesium hydroxide solution into the mixed solution, adjusting the pH value of the solution to 11, and stirring for reacting for 1 hour to obtain a coating product. And filtering and drying the coating reaction product, performing ball milling and crushing treatment for 10min under the conditions that the ball-material ratio is 4:1 and the rotating speed is 10Hz to obtain coating product powder, and performing surface modification treatment on the coating product powder by using a mixture of an aluminate coupling agent and vinyl trimethoxy silane at the modification temperature of 105 ℃ to obtain the inorganic flame retardant.

Example 5

The preparation steps of the inorganic flame retardant of the embodiment are as follows:

adding 100mL of vinyl silicone oil, 1.02g of sodium dodecyl benzene sulfonate and 700mL of water into a flask with a mechanical stirring device, uniformly stirring and mixing, adding 575g of styrene and 200g of tridecafluorooctyl methacrylate, continuously uniformly stirring, adding 300.1g of montmorillonite, heating to 75 ℃ under the protection of nitrogen, adding 0.03g of azobisisobutyronitrile to initiate reaction, stirring and reacting for 5.5 hours, washing for 3 times by deionized water, dispersing in ethanol, treating at 60 ℃ for 20min to remove a solvent, and drying to obtain the montmorillonite subjected to super-hydrophobic modification treatment. And dispersing the montmorillonite subjected to the super-hydrophobic modification treatment in a sodium hexametaphosphate solution with the concentration of 0.1g/L to obtain montmorillonite dispersion liquid. Heating the montmorillonite dispersion liquid to 40 ℃, adding a boric acid saturated solution, adjusting the pH value to 4.5, and stirring for reaction for 30min to obtain a mixed solution. And adding an aluminum hydroxide solution into the mixed solution, adjusting the pH value of the solution to 12.5, and stirring for reaction for 1 hour to obtain a coating product. And filtering and drying the coating reaction product, performing ball milling and crushing treatment for 5min under the conditions that the ball-to-material ratio is 4:1 and the rotating speed is 10Hz to obtain coating product powder, and performing surface modification treatment on the coating product powder by using vinyltriethoxysilane at the modification temperature of 120 ℃ to obtain the inorganic flame retardant.

Example 6

The preparation steps of the inorganic flame retardant of the embodiment are as follows:

adding 100mL of vinyl silicone oil, 1.01g of sodium dodecyl benzene sulfonate and 700mL of water into a flask with a mechanical stirring device, uniformly stirring and mixing, adding 575g of styrene and 200g of tridecafluorooctyl methacrylate, continuously uniformly stirring, adding 300g of montmorillonite, heating to 75 ℃ under the protection of nitrogen, adding 0.03g of azobisisobutyronitrile for initiating reaction, stirring for 6 hours, washing for 3 times by deionized water, dispersing in ethanol, treating at 60 ℃ for 20min to remove a solvent, and drying to obtain the montmorillonite subjected to super-hydrophobic modification treatment. And dispersing the montmorillonite subjected to the super-hydrophobic modification treatment in a sodium hexametaphosphate solution with the concentration of 0.2g/L to obtain montmorillonite dispersion liquid. Heating the montmorillonite dispersion liquid to 40 ℃, adding a boric acid saturated solution, adjusting the pH value to 4.5, and stirring for reaction for 30min to obtain a mixed solution. And adding an aluminum hydroxide solution into the mixed solution, adjusting the pH value of the solution to 11.5, and stirring for reaction for 1.5 hours to obtain a coating product. And filtering and drying the coating reaction product, performing ball milling and crushing treatment for 5min under the conditions that the ball-material ratio is 4:1 and the rotating speed is 10Hz to obtain coating product powder, and performing surface modification treatment on the coating product powder by using an aluminate coupling agent at the modification temperature of 110 ℃ to obtain the inorganic flame retardant.

Comparative example 1

The inorganic flame retardant of comparative example 1 was a commercially available inorganic flame retardant.

Comparative example 2

The inorganic flame retardant of comparative example 2 was identical to example 6 above except that montmorillonite which had not been subjected to superhydrophobic modification was used and the other raw materials and preparation steps were the same.

Comparative example 3

The inorganic flame retardant of comparative example 3 was identical to example 6 above in the raw materials and the preparation steps except that the depolymerization treatment of the coated product and the surface modification treatment of the coupling agent were omitted.

Comparative example 4

The inorganic flame retardant of comparative example 4 was prepared in the same manner as in example 6 except that the step of "heating the montmorillonite dispersion to 40 ℃, adding a boric acid saturated solution, adjusting the pH to 4.5, and stirring for reaction for 30min to obtain a mixed solution" was omitted.

Sealants were prepared by using the inorganic flame retardants of examples 1 to 6 and comparative examples 1 to 4, respectively, according to the following methods:

adding 100 parts of dihydroxy polydimethylsiloxane, 40 parts of polydimethylsiloxane, 30 parts of silicon micropowder and 20 parts of inorganic flame retardant into a kneader, dehydrating and blending for 60min at the temperature of 130 ℃ and the vacuum degree of 0.09MPa, and cooling to room temperature to obtain a base material; adding the base material into a planetary stirrer, adding 3 parts of phenyl tributyl ketoxime silane and 0.2 part of dibutyltin dilaurate, and carrying out chemical reaction for 60 minutes at a vacuum degree of 0.09MPa and a rotating speed of 300rpm to obtain the product. Sealants to which the inorganic flame retardants of examples 1 to 6 and comparative examples 1 to 4 were added were respectively obtained by the above preparation methods, and the following performance tests were performed on each group of sealants, and the test results are shown in tables 1 and 2 below.

The method for testing various performance indexes comprises the following steps: the fire resistance integrity, fire resistance and heat insulation, corrosion resistance, humidity resistance and freeze-thaw resistance are all tested according to GB 23864; surface drying time, cohesiveness (including 100% cohesiveness of definite elongation, 25% cohesiveness of cold drawing and hot pressing, and cohesiveness of definite elongation after soaking in water), heat aging, and flame retardant rating were tested according to GB/T24267; the elongation at break was tested according to GB/T13477.8.

TABLE 1

TABLE 2

According to the test results of the above tables 1 and 2, the sealant prepared by using the inorganic flame retardant of the embodiments 1 to 6 of the invention has excellent fire resistance integrity and fire resistance and heat insulation, the flame retardant grade can reach FV0 grade, and the sealant has the advantages of short surface drying time, good cohesiveness, good thermal aging resistance and good elongation at break. The sealant prepared by using the inorganic flame retardant of comparative example 1 has inferior fire resistance integrity, fire resistance and heat insulation performance, fire resistance grade, surface dry time, adhesive property, heat aging resistance and elongation at break compared with the sealant prepared by using the inorganic flame retardant of example 6. Obviously, the inorganic flame retardant provided by the embodiment of the invention has better comprehensive performances of fire resistance, flame retardance, adhesion, aging resistance and the like compared with the existing commercially available inorganic flame retardant. In addition, as can be seen from the results of comparing the performances of the inorganic flame retardants of comparative examples 2 to 4 and example 6, the fire resistance integrity, fire resistance and heat insulation properties and flame retardant properties of the inorganic flame retardant can be significantly improved by using the super-hydrophobic modified montmorillonite to perform depolymerization and coupling agent surface modification treatment on the coated product and performing borate intercalation treatment on the montmorillonite. The test results show that the inorganic flame retardant of the embodiments 1-6 of the invention can be well dispersed in the sealant and can be well compatible with the high molecular substance in the sealant, so that the sealant has excellent fire resistance and flame retardance.

In addition, the inventors of the present invention found through experimental studies that if the inorganic flame retardant of comparative example 1 reaches the flame retardant rating of FV0, the addition amount thereof needs to be increased to 100 parts, which is significantly more than 20 parts in the examples of the present invention. That is, the inorganic flame retardant provided by the embodiment of the invention is used in a smaller amount and has lower cost at the same flame retardant grade.

In addition, the oxygen indexes of the inorganic flame retardants of the examples 1 to 6 of the present invention were tested according to the test method of GB/T2406.2-2009, and the test results show that the oxygen indexes of the inorganic flame retardants of the examples 1 to 6 of the present invention are all lower than 30%.

The inorganic flame retardants of example 6 and comparative example 1 were formulated into rubber sealants according to the following formulations, respectively: 165117 kg of SEBS, 14kg of paraffin oil 250SN, 101-805.5kg of TPV, 380Y 10kg of PP R380, 55kg of low-density polyethylene, 0.2kg of hindered phenol stabilizers, 10760.2 kg of antioxidants, 1.5kg of inorganic flame retardants and 1kg of processing aids. Weighing the materials according to the formula, mixing all the materials, feeding the materials into a double-screw extruder from a feeder, shearing and mixing, extruding by a machine head, drawing strips, air cooling, granulating, drying and packaging to obtain the rubber sealing material (particles). Then, the rubber sealing materials obtained in the above example 6 and comparative example 1 were subjected to the performance test in the following manner, and the test results are shown in Table 3 below.

The test method comprises the following steps: the Shore hardness is tested according to GB/T2411-1989; tensile break strength was tested according to GB/T1040-1992; tensile elongation at break was tested according to GB/T1040-1992; tear strength was tested according to GB/T529-1999; permanent compression set (70. + -. 1 ℃ C.) times 22h (type A specimen) was tested according to GB/T7759-1996.

TABLE 3

From the above table 3, it can be seen that the indexes of shore hardness, tensile breaking strength, tensile breaking elongation, tearing strength and permanent compression set of the rubber sealing material adopting the inorganic flame retardant of the embodiment 6 of the invention all meet and exceed the requirements of the injection molding indexes of the rubber-plastic sealing strip TPE for the GB/T21282-2007 passenger vehicle, and the index values are all superior to those of the rubber sealing material adopting the commercially available inorganic flame retardant of the comparative example 1. The inorganic flame retardant prepared by the preparation method can be well dispersed in the rubber and plastic product and can be well compatible with the organic high polymer in the rubber and plastic product, so that the rubber and plastic product has excellent mechanical properties.

In summary, in the preparation method of the inorganic flame retardant provided by the embodiment of the invention, the montmorillonite subjected to the super-hydrophobic modification treatment is dispersed in the polymeric phosphate solution, then the temperature is raised to 40-50 ℃, the boric acid saturated solution is added, and the stirring reaction is carried out so that borate ions are inserted into the interlayer structure of the montmorillonite subjected to the super-hydrophobic modification treatment, thereby being beneficial to improving the smoke suppression performance of the inorganic flame retardant; then adding the obtained mixed solution into an aluminum hydroxide solution or a magnesium hydroxide solution for coating reaction to obtain an aluminum hydroxide coated or magnesium hydroxide coated product, which can obviously improve the flame retardant property of the inorganic flame retardant; then, the obtained coating product is filtered, dried and depolymerized, and then is subjected to surface modification treatment by a coupling agent, so that the compatibility of the inorganic flame retardant and a high polymer material and the dispersibility of the inorganic flame retardant in a material system are improved. The inorganic flame retardant prepared by the preparation method provided by the embodiment of the invention has excellent flame retardant effect and obviously improved smoke suppression performance; in addition, the inorganic flame retardant can be well compatible with a high polymer material, can be uniformly dispersed in a material system, and is favorable for improving the mechanical property of the material; when the same flame-retardant grade is achieved, the addition amount is obviously less than that of the traditional inorganic flame retardant, so that the cost can be reduced.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.