Preparation of a nano flame retardant and smoke suppressant and flame retardant and smoke suppressant polylactic acid fiber material

Abstract

The invention discloses the preparation of a nano flame retardant and smoke suppressant and a flame retardant and smoke suppressant polylactic acid fiber material, and relates to the technical field of functional modification of polylactic acid. The invention prepares a lactic acid cerium-based melamine phytic acid nano flame retardant and smoke suppressant, combining the flame retardant advantages of melamine and phytic acid; and utilizing the cerium-based melamine phytic acid nano flame retardant and smoke suppressant by combining the cerium-based melamine phytic acid nano flame retardant and smoke suppressant with the melamine phytic acid nano flame retardant to prepare the cerium-based melamine phytic acid nano flame retardant and smoke suppressant; and in order to improve the compatibility of the flame retardant and smoke suppressant with a polylactic acid matrix, the invention introduces a lactic acid group into the flame retardant and smoke suppressant system, thereby giving the flame retardant and smoke suppressant excellent compatibility with the polylactic acid matrix.

Description

Technical field:

[0001] The invention relates to the technical field of functional modification of polylactic acid, and in particular to the preparation of a nano flame retardant and smoke suppressant and a flame retardant and smoke suppressant polylactic acid fiber material. Background technology:

[0002] Polylactic acid (PLA) is an environmentally friendly polymer material with good biocompatibility and degradability, and is considered to be a green bio-based material with broad development prospects. However, the element composition (carbon, hydrogen, oxygen) and molecular chain structure (ester bonds are easily destroyed at high temperatures to generate volatile combustibles) of PLA determine that it has the same defect of being easy to burn as general polymer materials. At the same time, polylactic acid will produce smoke containing toxic and corrosive chemicals when burning, and inhaling smoke leading to coma and suffocation is also an important cause of casualties in fires. In the prior art, flame retardant additives commonly used for flame retardant of polylactic acid, such as halogen, phosphorus system, phosphorus-nitrogen system and expansion flame retardant, are less helpful in suppressing the smoke when polylactic acid burns, and usually have a negative impact on the physical and mechanical properties of polylactic acid.

[0003] Melamine is a nitrogen-rich, thermally stable organic product that can absorb a large amount of heat during its endothermic sublimation process. Phytic acid has a high phosphorus content and is an effective green and environmentally friendly bio-based phosphorus flame retardant. Melamine phytic acid is prepared by combining the flame retardant advantages of phytic acid and melamine, and has been widely used in the field of flame retardancy. However, when melamine phytic acid is applied to polylactic acid materials, it has no effect on suppressing smoke during combustion and has poor compatibility with the polylactic acid matrix, which affects its flame retardant effect and the physical and mechanical properties of the polylactic acid material. Summary of the invention:

[0004] In view of the fact that polylactic acid is flammable and produces a large amount of smoke when burned, phosphorus-nitrogen flame retardants with good flame retardant effects are less helpful in suppressing smoke when polylactic acid burns, and usually have poor compatibility with the polylactic acid matrix. Provided are a method for preparing an environmentally friendly flame retardant and smoke suppressant that has excellent compatibility with polylactic acid, and a flame retardant and smoke suppressant polylactic acid fiber material prepared thereby.

[0005] The technical problem to be solved by the present invention is achieved by adopting the following technical solutions:

[0006] One of the objects of the present invention is to provide a method for preparing melamine phytic acid, comprising the following steps:

[0007] (1) dispersing melamine in water to obtain a melamine dispersion;

[0008] (2) dissolving phytic acid in water to obtain a phytic acid solution;

[0009] (3) adding the phytic acid solution dropwise to the melamine dispersion and stirring to obtain a slurry;

[0010] (4) The slurry is transferred to a hydrothermal reactor, aged, allowed to stand, filtered, and dried to obtain melamine phytic acid.

[0011] The second object of the present invention is to provide a method for preparing cerium-based melamine phytic acid, comprising the following steps:

[0012] (1) dispersing the melamine phytic acid prepared above into water to obtain a melamine phytic acid dispersion;

[0013] (2) dissolving cerium nitrate in water to obtain a cerium nitrate solution;

[0014] (3) adding the cerium nitrate solution dropwise into the sodium melamine phytate dispersion, stirring, standing, filtering, and drying to obtain cerium-based melamine phytate.

[0015] The third object of the present invention is to provide a method for preparing cerium lactate-based melamine phytic acid, comprising the following steps:

[0016] (1) dispersing the cerium-based melamine-phytic acid prepared above into water to obtain a cerium-based melamine-phytic acid dispersion;

[0017] (2) dissolving sodium lactate in water to obtain a sodium lactate solution;

[0018] (3) adding the sodium lactate solution dropwise into the cerium-based melamine phytic acid dispersion, adjusting the pH value of the reaction system, stirring the reaction, standing, filtering, and drying to obtain the cerium-based melamine phytic acid lactate.

[0019] The fourth object of the present invention is to provide a nano flame retardant and smoke suppressant, which is at least one of the melamine phytic acid, cerium-based melamine phytic acid, and lactate cerium-based melamine phytic acid prepared above.

[0020] A fifth object of the present invention is to provide a flame retardant and smoke suppressant polylactic acid composite material, comprising polylactic acid and the aforementioned nano flame retardant and smoke suppressant.

[0021] The sixth object of the present invention is to provide a method for preparing a flame retardant and smoke suppressant polylactic acid composite material, wherein the dried nano flame retardant and smoke suppressant is evenly mixed with the polylactic acid resin, and then added into a twin-screw extruder, extruded and granulated to obtain a flame retardant and smoke suppressant polylactic acid composite material.

[0022] The seventh object of the present invention is to provide a flame retardant and smoke suppressant polylactic acid fiber material, which is obtained by melt spinning the aforementioned flame retardant and smoke suppressant polylactic acid composite material.

[0023] The beneficial effects of the present invention are as follows: the present invention prepares a lactic acid cerium-based melamine phytic acid nano flame retardant and smoke suppressant, combines the flame retardant advantages of melamine and phytic acid, and prepares the melamine phytic acid nano flame retardant by reasonably controlling the reaction conditions; and utilizes the cerium's ability to capture free radicals generated during the combustion of polymers, smoke suppression and catalytic carbonization, and combines with the melamine phytic acid nano flame retardant to prepare the cerium-based melamine phytic acid nano flame retardant and smoke suppressant; and in order to improve the compatibility of the flame retardant and smoke suppressant with a polylactic acid matrix, the present invention prepares the lactic acid cerium-based melamine phytic acid nano flame retardant and smoke suppressant by a precipitation method, utilizes the "like dissolves like" principle, introduces lactic acid groups into the flame retardant and smoke suppression system, and gives the flame retardant and smoke suppression agent excellent compatibility with the polylactic acid matrix; and then the flame retardant and smoke suppression agent are melt-spun with polylactic acid to prepare flame retardant and smoke suppression polylactic acid fibers. Specific implementation method:

[0024] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments.

[0025] The present invention provides a method for preparing melamine phytic acid, comprising the following steps:

[0026] (1) dispersing melamine in water to obtain a melamine dispersion;

[0027] (2) dissolving phytic acid in water to obtain a phytic acid solution;

[0028] (3) adding the phytic acid solution dropwise to the melamine dispersion and stirring to obtain a slurry;

[0029] (4) The slurry is transferred to a hydrothermal reactor, aged, allowed to stand, filtered, and dried to obtain melamine phytic acid.

[0030] In step (1), the mass fraction of melamine in the melamine dispersion is 5-10%.

[0031] In step (2), the mass fraction of phytic acid in the phytic acid solution is 10-20%.

[0032] In step (3), the mass ratio of melamine in the melamine dispersion to phytic acid in the phytic acid solution is 1:(1-5).

[0033] In step (4), the aging temperature is 60-80° C. and the aging time is 24-48 hours.

[0034] The present invention also provides a method for preparing cerium-based melamine phytic acid, comprising the following steps:

[0035] (1) dispersing the melamine phytic acid prepared above into water to obtain a melamine phytic acid dispersion;

[0036] (2) dissolving cerium nitrate in water to obtain a cerium nitrate solution;

[0037] (3) adding the cerium nitrate solution dropwise into the sodium melamine phytate dispersion, stirring, standing, filtering, and drying to obtain cerium-based melamine phytate.

[0038] In step (1), the mass fraction of melamine phytic acid in the melamine phytic acid dispersion is 5-10%.

[0039] In step (2), the mass fraction of cerium nitrate in the cerium nitrate solution is 10-20%.

[0040] In step (3), the mass ratio of melamine phytic acid in the melamine phytic acid dispersion to cerium nitrate in the cerium nitrate solution is 1:(1-5).

[0041] The present invention also provides a method for preparing cerium lactate-based melamine phytic acid, comprising the following steps:

[0042] (1) dispersing the cerium-based melamine-phytic acid prepared above into water to obtain a cerium-based melamine-phytic acid dispersion;

[0043] (2) dissolving sodium lactate in water to obtain a sodium lactate solution;

[0044] (3) adding the sodium lactate solution dropwise into the cerium-based melamine phytic acid dispersion, adjusting the pH value of the reaction system, stirring the reaction, standing, filtering, and drying to obtain the cerium-based melamine phytic acid lactate.

[0045] In step (1), the mass fraction of cerium-based melamine-phytic acid in the cerium-based melamine-phytic acid dispersion is 5-15%.

[0046] In step (2), the mass fraction of sodium lactate in the sodium lactate solution is 15-20%.

[0047] In step (3), the mass ratio of cerium-based melamine phytic acid in the cerium-based melamine phytic acid dispersion to sodium lactate in the sodium lactate solution is (1-3):1; the pH value of the reaction system is 6-8, and the pH regulator is ammonia water or NaHCO3.

[0048] The present invention also provides a nano flame retardant and smoke suppressant, wherein the nano flame retardant and smoke suppressant is at least one of melamine phytic acid, cerium-based melamine phytic acid, and lactate cerium-based melamine phytic acid.

[0049] The present invention also provides a flame retardant and smoke suppressant polylactic acid composite material, comprising polylactic acid and the aforementioned nano flame retardant and smoke suppressant.

[0050] Preferably, the mass ratio of the nano flame retardant and smoke suppressant to the polylactic acid resin is 8-15%.

[0051] The present invention also provides a method for preparing a flame retardant and smoke suppressant polylactic acid composite material, wherein the dried nano flame retardant and smoke suppressant is evenly mixed with polylactic acid resin, then added into a twin-screw extruder, extruded and granulated to obtain the flame retardant and smoke suppressant polylactic acid composite material.

[0052] Preferably, the twin-screw extruder has a melt temperature of 170-190° C. and a rotation speed of 200-250 rpm.

[0053] The present invention also provides a flame retardant and smoke suppressing polylactic acid fiber material, which is prepared by melt spinning the flame retardant and smoke suppressing polylactic acid composite material.

[0054] Preferably, the spinning temperature of the melt spinning is 220-245° C., and the spinning speed is 1000-3000 m / min.

[0055] The technical solution of the present invention is described in detail below through specific embodiments.

[0056] Example 1

[0057] Preparation of melamine phytic acid: 25g of melamine and 475g of water are added to a reaction kettle, the stirring speed is controlled to 600r / min, and the mixture is stirred at room temperature for 30min until uniformly dispersed to obtain a melamine dispersion; 25g of phytic acid is weighed and dissolved in 225g of water to obtain a phytic acid aqueous solution; the phytic acid aqueous solution is slowly added dropwise to the melamine dispersion, and after the addition is completed, the stirring speed is controlled to 600r / min, and the mixture is stirred at room temperature for 1h to obtain a slurry; the slurry is transferred to a hydrothermal reaction autoclave, and the mixture is heat-aged at 60°C for 48h; after the aging is completed, the mixture is cooled, allowed to stand, vacuum filtered, washed with water 3 times, and dried in an oven at 80°C for 12h to obtain melamine phytic acid.

[0058] Preparation of cerium-based melamine phytic acid: 30 g of melamine phytic acid was dispersed in 570 g of water and ultrasonically treated at room temperature for 0.5 h; 30 g of cerium nitrate was weighed and dissolved in 270 g of water to prepare a cerium nitrate aqueous solution; the cerium nitrate aqueous solution was dropwise added to the melamine sodium phytate dispersion, and after the dropwise addition was completed, the stirring speed was controlled to 600 r / min and stirred at room temperature for 4 h to obtain a cerium-based melamine phytic acid dispersion.

[0059] Preparation of cerium lactate-based melamine phytic acid: weigh 45g of sodium lactate and dissolve it in 255g of water to obtain a sodium lactate aqueous solution; add the sodium lactate aqueous solution dropwise to the cerium-based melamine phytic acid dispersion, and after the dropwise addition is completed, adjust the pH value of the reaction system to 7 with ammonia water, heat to 30°C, control the stirring speed to 600r / min, and stir the reaction for 8h; after the reaction is completed, let it stand, vacuum filter, and dry it in an oven at 80°C for 12h to obtain cerium lactate-based melamine phytic acid.

[0060] The lactic acid cerium-based melamine phytic acid and polylactic acid resin were dried at 60°C for 24 hours to remove moisture. After the dried 24g lactic acid cerium-based melamine phytic acid and 276g polylactic acid resin were mixed evenly, they were added into a twin-screw extruder and melt-blended at 170°C at a speed of 250rpm, and extruded into granules. The flame-retardant and smoke-suppressing polylactic acid granules were melt-spun at 220°C at a spinning speed of 1000m / min to prepare flame-retardant and smoke-suppressing polylactic acid fibers with a flame-retardant and smoke-suppressing agent content of 8%.

[0061] Example 2

[0062] Preparation of melamine phytic acid: adding 50g of melamine and 450g of water into a reaction kettle, controlling the stirring speed to 1200r / min, stirring at room temperature for 20min until uniformly dispersed, to obtain a melamine dispersion; weighing another 50g of phytic acid and dissolving it in 200g of water to obtain a phytic acid aqueous solution; slowly dropping the phytic acid aqueous solution into the melamine dispersion, after the dropping is completed, controlling the stirring speed to 1200r / min, stirring at room temperature for 0.5h, to obtain a slurry; transferring the above slurry into a hydrothermal reaction autoclave, and aging at 80°C for 24h; cooling after aging, standing, vacuum filtering, washing with water 3 times, and drying in an oven at 100°C for 8h to obtain melamine phytic acid.

[0063] Preparation of cerium-based melamine phytic acid: 50 g of melamine phytic acid was dispersed in 450 g of water and ultrasonically treated at room temperature for 0.5 h; 50 g of cerium nitrate was weighed and dissolved in 250 g of water to prepare a cerium nitrate aqueous solution; the cerium nitrate aqueous solution was dropwise added to the melamine sodium phytate dispersion, and after the dropwise addition was completed, the stirring speed was controlled to 1200 r / min, and the mixture was stirred at room temperature for 2 h to obtain a cerium-based melamine phytic acid dispersion.

[0064] Preparation of cerium lactate-based melamine phytic acid: weigh 60g of sodium lactate and dissolve it in 240g of water to obtain a sodium lactate aqueous solution; add the sodium lactate aqueous solution dropwise to the cerium-based melamine phytic acid dispersion, and after the dropwise addition is completed, adjust the pH value of the reaction system to 6 with ammonia water, heat to 50°C, control the stirring speed to 1200r / min, and stir the reaction for 6h; after the reaction is completed, let it stand, vacuum filter, and dry in an oven at 100°C for 8h to obtain cerium lactate-based melamine phytic acid.

[0065] Dry the lactic acid cerium-based melamine phytic acid and polylactic acid resin at 60°C for 24 hours to remove moisture. After the dried 50g lactic acid cerium-based melamine phytic acid and 450g polylactic acid resin are evenly mixed, add them into a twin-screw extruder at 180°C and 250rpm for melt blending, and extrude them into granules. The flame-retardant and smoke-suppressing polylactic acid granules are melt-spun at 230°C at a spinning speed of 2000m / min to prepare flame-retardant and smoke-suppressing polylactic acid fibers with a flame-retardant and smoke-suppressing agent content of 10%.

[0066] Example 3

[0067] Preparation of melamine phytic acid: 40g of melamine and 460g of water are added to a reaction kettle, the stirring speed is controlled to 800r / min, and the mixture is stirred at room temperature for 30min until uniformly dispersed to obtain a melamine dispersion; 45g of phytic acid is weighed and dissolved in 255g of water to obtain a phytic acid aqueous solution; the phytic acid aqueous solution is slowly added dropwise to the melamine dispersion, and after the addition is completed, the stirring speed is controlled to 800r / min, and the mixture is stirred at room temperature for 1h to obtain a slurry; the slurry is transferred to a hydrothermal reaction autoclave, and the mixture is heat-aged at 80°C for 36h; after the aging is completed, the mixture is cooled, allowed to stand, vacuum filtered, washed with water 3 times, and dried in an oven at 80°C for 12h to obtain melamine phytic acid.

[0068] Preparation of cerium-based melamine phytic acid: 40 g of melamine phytic acid was dispersed in 460 g of water and ultrasonically treated at room temperature for 0.5 h; 40 g of cerium nitrate was weighed and dissolved in 260 g of water to prepare a cerium nitrate aqueous solution; the cerium nitrate aqueous solution was dropwise added to the melamine sodium phytate dispersion, and after the dropwise addition was completed, the mechanical stirring speed was controlled to 800 r / min, and the mixture was stirred at room temperature for 4 h to obtain a cerium-based melamine phytic acid dispersion.

[0069] Preparation of cerium lactate-based melamine phytic acid: weigh 80g of sodium lactate and dissolve it in 320g of water to obtain a sodium lactate aqueous solution; add the sodium lactate aqueous solution dropwise to the cerium-based melamine phytic acid dispersion, and after the dropwise addition is completed, adjust the pH value of the reaction system to 8 with ammonia water, heat to 40°C, control the mechanical stirring speed to 800r / min, and stir the reaction for 6h; after the reaction is completed, let it stand, vacuum filter, and dry it in an oven at 80°C for 12h to obtain cerium lactate-based melamine phytic acid.

[0070] Dry the cerium lactate-based melamine phytic acid and polylactic acid resin at 60°C for 24 hours to remove moisture. Mix the dried 60g cerium lactate-based melamine phytic acid and 440g polylactic acid resin evenly, add them into a twin-screw extruder, melt blend at 180°C and 250rpm, and extrude them into granules. Melt-spin the flame-retardant and smoke-suppressing polylactic acid granules at 230°C at a spinning speed of 2000m / min to prepare flame-retardant and smoke-suppressing polylactic acid fibers with a flame-retardant and smoke-suppressing agent content of 12%.

[0071] Example 4

[0072] The preparation method of cerium lactate-based melamine phytic acid and the preparation method of flame retardant and smoke suppressant polylactic acid fiber in Example 4 are the same as those in Example 3, only the content of flame retardant and smoke suppressant in the fiber is changed to prepare flame retardant and smoke suppressant polylactic acid fiber with a flame retardant and smoke suppressant content of 15%.

[0073] Comparative Example 1

[0074] The preparation method of melamine phytic acid in Reference Example 1 is the same as that in Example 1.

[0075] The dried 24g melamine phytic acid and 276g polylactic acid resin were melt-spun, and the spinning performance was very poor and could not be spun into silk. By hot pressing into strips, 24g melamine phytic acid and 276g polylactic acid resin were melted, extruded into granules, and then hot pressed at 180°C into 2 mm thick strips to obtain a flame retardant and smoke-suppressing polylactic acid material with a melamine phytic acid content of 8%.

[0076] Comparative Example 2

[0077] The preparation method of melamine phytic acid and cerium-based melamine phytic acid in Comparative Example 2 is the same as that in Example 1.

[0078] The dried 24g cerium-based melamine phytic acid and 276g polylactic acid resin were melt-spun, and the spinning performance was very poor and could not be spun into silk. By hot pressing into strips, 24g cerium-based melamine phytic acid and 276g polylactic acid resin were melted, extruded into granules, and then hot-pressed at 180°C into 2 mm thick strips to obtain a flame retardant and smoke-suppressing polylactic acid material with a cerium-based melamine phytic acid content of 8%.

[0079] Comparative Example 3

[0080] The polylactic acid fiber is prepared directly by melt spinning the polylactic acid without adding a flame retardant or smoke suppressant.

[0081] Performance Testing

[0082] Flame retardant and smoke suppression performance test:

[0083] The limiting oxygen index is tested according to the oxygen index method test standard GB / T 5454-1997 for combustion performance test using an FAA type oxygen index instrument.

[0084] The smoke suppression performance was tested in accordance with GB / T 16172-2007 using a FTT0007 cone calorimeter at a radiation power of 50kW / m 2 The smoke density (SEA) of control sample 3 was recorded as 100%.

[0085] Mechanical properties test:

[0086] According to GB / T 14344-2008 “Test method for tensile properties of chemical fiber filaments”, the YG061M single yarn strength tester was used to test the breaking strength and elongation of the fiber.

[0087] The test results are shown in Table 1.

[0088] Table 1 Flame retardant and smoke suppression properties and mechanical properties of polylactic acid fibers obtained in Examples 1-4 and Comparative Examples 1-3

[0089]

[0090] As can be seen from Table 1, when the lactic acid cerium-based melamine phytic acid prepared by the present invention is used as a nano flame retardant and smoke suppressant, when the amount of the flame retardant and smoke suppressant added in the blending component is 8%, the limiting oxygen index of the prepared flame retardant and smoke suppressant polylactic acid fiber can reach 26.4%, and the smoke density is reduced to 67% during combustion, and the flame retardant and smoke suppressant effect is obvious. When the amount of the flame retardant and smoke suppressant added is increased to 15%, the flame retardant and smoke suppressant performance of the polylactic acid fiber is further improved, the limiting oxygen index reaches 29.7%, and the smoke density is reduced to 37% during combustion. At the same time, the breaking strength and elongation at break of the polylactic acid fiber are improved, indicating that the addition of the nano flame retardant and smoke suppressant is helpful to the mechanical properties of the fiber, which reflects that the flame retardant and smoke suppressant designed by the present invention have excellent compatibility with polylactic acid. As can be seen from Comparative Example 1, when melamine phytic acid is added as a nano flame retardant and smoke suppressant, although the flame retardant properties of the material are improved, there is no obvious smoke suppression effect. From the comparative example 2, it can be seen that the introduction of rare earth metal cerium is helpful to suppress the smoke density when polylactic acid is burned, but due to the poor compatibility with polylactic acid, the flame retardant and smoke suppression effect is affected. At the same time, from the comparative examples 1 and 2, it can be seen that when the lactic acid-based modification is not adopted, the blended material cannot be spun into silk due to the poor compatibility between the flame retardant and polylactic acid.

[0091] In summary, the lactate cerium-based melamine phytic acid nano flame retardant and smoke suppressant prepared by the present invention combines the flame retardant advantages of melamine and phytic acid, utilizes the smoke suppression and catalytic carbonization effects of cerium as a rare earth metal element, and adopts the "like dissolves like" principle to introduce lactic acid groups, thereby preparing a flame retardant and smoke suppressant with excellent flame retardant and smoke suppression effects and excellent compatibility with a polylactic acid matrix, and obtaining polylactic acid fibers with good flame retardant and smoke suppression properties and good physical and mechanical properties.

[0092] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing cerium lactate-based melamine phytic acid, characterized in that: The steps include: (1) dispersing cerium-based melamine phytic acid in water to obtain a cerium-based melamine phytic acid dispersion; (2) dissolving sodium lactate in water to obtain a sodium lactate solution; (3) adding the sodium lactate solution dropwise into the cerium-based melamine phytic acid dispersion, adjusting the pH value of the reaction system, stirring the reaction, standing, filtering, and drying to obtain the cerium-based melamine phytic acid lactate.

2. The preparation method according to claim 1, characterized in that: The mass fraction of cerium-based melamine-phytic acid in the cerium-based melamine-phytic acid dispersion is 5-15%; In step (2), the mass fraction of sodium lactate in the sodium lactate solution is 15-20%; In step (3), the mass ratio of cerium-based melamine phytic acid in the cerium-based melamine phytic acid dispersion to sodium lactate in the sodium lactate solution is (1-3):1; the pH value of the reaction system is 6-8, and the pH regulator is ammonia water or NaHCO3.

3. The preparation method according to claim 1, characterized in that: The preparation method of the cerium-based melamine phytic acid comprises the following steps: (1) dispersing melamine phytic acid in water to obtain a melamine phytic acid dispersion; (2) dissolving cerium nitrate in water to obtain a cerium nitrate solution; (3) adding the cerium nitrate solution dropwise into the melamine phytic acid dispersion, stirring, standing, filtering, and drying to obtain cerium-based melamine phytic acid.

4. The preparation method according to claim 3, characterized in that: The mass fraction of melamine phytic acid in the melamine phytic acid dispersion is 5-10%; The mass fraction of cerium nitrate in the cerium nitrate solution is 10-20%; The mass ratio of melamine phytic acid in the melamine phytic acid dispersion to cerium nitrate in the cerium nitrate solution is 1:(1-5).

5. The preparation method according to claim 3, characterized in that: The preparation method of melamine phytic acid comprises the following steps: (1) dispersing melamine in water to obtain a melamine dispersion; (2) dissolving phytic acid in water to obtain a phytic acid solution; (3) adding the phytic acid solution dropwise to the melamine dispersion and stirring to obtain a slurry; (4) The slurry is transferred to a hydrothermal reactor, aged, allowed to stand, filtered, and dried to obtain melamine phytic acid.

6. The preparation method according to claim 5, characterized in that: The mass fraction of melamine in the melamine dispersion is 5-10%; The mass fraction of phytic acid in the phytic acid solution is 10-20%; The mass ratio of melamine in the melamine dispersion to phytic acid in the phytic acid solution is 1:(1-5); The aging temperature is 60-80°C and the aging time is 24-48h.

7. A nano flame retardant and smoke suppressant, characterized in that: The nano flame retardant and smoke suppressant is cerium lactate-based melamine phytic acid prepared by the preparation method described in any one of claims 1 to 6.

8. A flame retardant and smoke suppressing polylactic acid composite material, characterized in that: Comprising polylactic acid and the nano flame retardant and smoke suppressant according to claim 7; The mass ratio of the nano flame retardant and smoke suppressant to the polylactic acid resin is 8-15%.

9. The method for preparing the flame-retardant and smoke-suppressing polylactic acid composite material according to claim 8, characterized in that: The dried nano flame retardant and smoke suppressant agent is mixed evenly with the polylactic acid resin, and then added into a twin-screw extruder for extrusion granulation to obtain a flame retardant and smoke suppressant polylactic acid composite material; The twin-screw extruder has a melting temperature of 170-190° C. and a rotation speed of 200-250 rpm.

10. A flame retardant and smoke suppressing polylactic acid fiber material, which is prepared by melt spinning the flame retardant and smoke suppressing polylactic acid composite material according to claim 8 or the flame retardant and smoke suppressing polylactic acid composite material prepared according to claim 9; The spinning temperature of the melt spinning is 220-245° C., and the spinning speed is 1000-3000 m / min.

Images