Intercalation assembled composite flame retardant, preparation method thereof and flame-retardant composition

Abstract

The invention provides an intercalation assembled composite flame retardant, a preparation method thereof and a flame-retardant composition, and the preparation method comprises the following steps: (1) reacting a metal salt with a phosphorus flame retardant to obtain an MOFs supported flame retardant; (2) modifying LDH by using phytic acid to obtain modified LDH; and (3) reacting the MOFs supported flame retardant with the modified LDH to obtain the intercalation assembled composite flame retardant. The intercalation assembled composite flame retardant provided by the invention can effectively improve the flame retardant property of a polymer matrix, and meanwhile, the intercalation assembled composite flame retardant has better dispersity and stability, is not easy to migrate and separate out, and is suitable for the development of high-performance flame-retardant materials.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of flame-retardant polymers, and particularly relates to an intercalation assembled composite flame retardant, a preparation method thereof and a flame-retardant composition. BACKGROUND

[0002] The air duct and the impeller are key components of the range hood for extracting oil fume. The main function of the air duct and the impeller is to generate negative pressure through rotation to extract the oil fume generated in the kitchen. After the oil fume passes through the filter of the range hood, it enters the air duct area of the range hood. The impeller of the range hood rotates to generate negative pressure to suck the oil fume into the pipeline and discharge it outdoors.

[0003] The materials of the air duct and the impeller of the range hood are generally divided into metal and plastic. The air duct and the impeller made of metal are more durable, but the noise is larger than that of the plastic impeller, and the price is also higher. The air duct and the impeller made of plastic have relatively small noise and lower cost. However, due to the existence of open fire and high temperature in the cooking environment, the plastic material in the range hood needs to meet the non-combustible or flame-retardant requirements.

[0004] For the flame-retardant modification of polyamide (PA6 or PA66) or polypropylene (PP) material impeller, a certain amount of halogen-based flame retardant or phosphorus-based flame retardant is usually added to the raw material, and then a flame-retardant range hood impeller is obtained through injection molding process. However, the flame-retardant plastic prepared by directly blending has the defects of excessive amount of flame retardant and reduced mechanical properties of the plastic substrate due to poor interfacial compatibility. In addition, in a high temperature and high humidity environment, the organic flame retardant in the material is easily decomposed and separated out, which not only reduces the flame-retardant performance of the material, but also causes problems such as white spots, white lines and white circles on the surface of the material, which affects the appearance of the impeller. The separated small molecules of the flame retardant also pose a threat to human health.

[0005] Phosphorus-based flame retardants have low price and good flame-retardant effect under high temperature conditions by capturing free radicals in the gas phase (PO· inhibits combustion chain reaction) and catalyzing carbon formation in the condensed phase (forms a heat-insulating and oxygen-insulating carbon layer). However, during use, the phosphorus-based flame retardant releases small molecules such as phosphate esters, which are easy to migrate to the surface from the material, and are prone to decomposition during long-term high-temperature use, resulting in a decrease in flame-retardant efficiency.

[0006] Therefore, there is an urgent need to develop a new type of flame-retardant material that has stable and excellent flame-retardant performance, good compatibility with plastic substrates and is not easy to separate out. SUMMARY

[0007] In view of the deficiencies of the prior art, the purpose of the present application is to provide an intercalation assembled composite flame retardant, a preparation method thereof and a flame-retardant composition.

[0008] To achieve this purpose, the present application adopts the following technical solutions:

[0009] In one aspect, the present application provides a preparation method of an intercalation assembled composite flame retardant, the preparation method comprising:

[0010] (1) reacting a metal salt with a phosphorus-based flame retardant to obtain a MOFs loaded flame retardant;

[0011] (2) modifying LDH with phytic acid to obtain modified LDH;

[0012] (3) reacting the MOFs loaded flame retardant and the modified LDH to obtain the intercalation assembled composite flame retardant.

[0013] MOFs (Metal-Organic Frameworks) are a new type of highly crystalline porous network inorganic-organic complex, and the present application applies it to the preparation of flame retardants. In the combustion process, MOFs can realize the physical confinement of flame retardant molecules through its highly ordered porous structure, which can effectively prevent the leakage and failure of flame retardants. At the same time, the thermal stability of MOFs and the "protective shell" effect of the framework can isolate the flame retardant contained in it from high-temperature oxygen, preventing the premature decomposition of the flame retardant. Therefore, by introducing MOFs, the present application can solve the shortcomings of easy migration and volatilization of organic flame retardants by using the adjustable pore size and rich pore structure of MOFs to encapsulate phosphorus-based flame retardants, and achieve the slow release of flame retardants.

[0014] At the same time, LDH (Layered Double Hydroxides) is an anionic layered compound, whose plate layer skeleton is composed of divalent and trivalent metal hydroxides. The plate layer is positively charged and has a large number of hydroxyl groups on the surface. The compensating anions and water molecules in the interlayer are combined with the main plate layer through hydrogen bonds, electrostatic forces and ionic bonds. In the present application, the introduction of phytic acid for the modification of LDH, the exchangeability of the anions in the interlayer of LDH, not only enables the modified agent phytic acid to be organically combined with LDH, but also provides advantageous conditions for its compounding with the polymer matrix. Moreover, the introduction of phytic acid for the modification of LDH, the phytic acid anions enter the interlayer of LDH through ion exchange, which can significantly increase the interlayer spacing of LDH, providing more dispersion space for the intercalation of MOFs loaded flame retardant, and thus enabling the MOFs loaded flame retardant to be intercalated in the interlayer of LDH containing phytic acid modified LDH, which helps to improve the dispersion uniformity of the flame retardant in the matrix, avoids the aggregation and sedimentation of the flame retardant, and thus improves the overall stability and performance of the modified flame retardant (intercalation assembled composite flame retardant).

[0015] In addition, phytic acid releases water vapor and carbon dioxide when heated, which dilutes the combustible gas, and the residual metal oxide can catalyze the formation of carbon and form a physical barrier. Therefore, the present application can improve the flame retardant effect (especially the carbon catalysis effect) of the flame retardant by introducing phytic acid.

[0016] That is, the intercalation assembled composite flame retardant provided by the present application has excellent flame retardant performance, good dispersibility and stability in a polymer matrix, and is not prone to agglomeration and precipitation, and can effectively solve the problems of poor flame retardant performance, easy agglomeration and poor stability of traditional flame retardants.

[0017] Preferably, step (1) comprises: reacting the metal salt, the phosphorus-based flame retardant and 2-methylimidazole in a solvent to obtain the MOFs loaded flame retardant.

[0018] Preferably, the mass ratio of the metal salt, the 2-methylimidazole and the phosphorus-based flame retardant is (40-60):(80-100):(20-40).

[0019] And / or, the metal salt comprises any one or a combination of at least two of a zinc salt, a copper salt, an iron salt, an aluminum salt or a magnesium salt, and the anion of the metal salt is a nitrate ion or a chloride ion.

[0020] And / or, the phosphorus-based flame retardant comprises any one or a combination of at least two of TCP, TPP, RDP, BDP, DOPO, DOPO-HQ, DOPO-NQ, CEPPA or MPP.

[0021] And / or, step (1) is carried out under sealed conditions, the reaction temperature is 65-70℃, and the reaction time is 15-20h.

[0022] Preferably, step (2) comprises: mixing a mixed solution of a divalent salt, a trivalent salt, sodium dodecylbenzenesulfonate and phytic acid with an alkaline solution to carry out a hydrothermal reaction, thereby obtaining the modified LDH.

[0023] Preferably, the cation in the divalent salt comprises any one or a combination of at least two of Cu 2+ , Zn 2+ , Ni 2+ or Mg 2+ .

[0024] And / or, the cation in the trivalent salt comprises Fe 3+ and / or Al 3+ .

[0025] And / or, the mass ratio of the divalent salt, the trivalent salt, sodium dodecylbenzenesulfonate and phytic acid is 100:(20-70):(10-30):(20-40).

[0026] And / or, the addition amount of the alkaline solution is such that the pH value of the reaction system is 7-10.

[0027] And / or, the solute used in the alkaline solution comprises any one or a combination of at least two of urea, ammonia, sodium hydroxide or potassium hydroxide.

[0028] And / or, the temperature of the hydrothermal reaction is 60-110℃, and the time is 10-24h.

[0029] Preferably, the reaction of step (3) is carried out in the presence of a promoter, the promoter comprising hexadecyl trimethyl ammonium bromide, and the promoter is added in an amount of 1-10% of the mass of the modified LDH.

[0030] And / or, the mass ratio of the MOFs loaded flame retardant and the modified LDH is 1:(0.8-1).

[0031] And / or, the temperature of the reaction of step (3) is 50-70℃, and the time is 12-24h.

[0032] In a second aspect, the present application provides an intercalated assembled composite flame retardant prepared by the preparation method of the first aspect.

[0033] In a third aspect, the present application provides a flame retardant composition comprising, in parts by weight, 70-95 parts of a polymer resin, 5-15 parts of the intercalated assembled composite flame retardant of the second aspect, 10-20 parts of glass fiber, 0.5-4 parts of a toughening agent, 3-8 parts of a compatibilizer, and 0.3-4 parts of an antioxidant.

[0034] Preferably, the polymer resin is selected from a polyamide resin and / or a polypropylene resin.

[0035] And / or, the toughening agent comprises any one or a combination of at least two of ethylene-propylene copolymer, ethylene-hexene copolymer, ethylene-butene copolymer, ethylene-octene copolymer, styrene-butadiene-styrene copolymer, or hydrogenated styrene-butadiene-styrene copolymer.

[0036] And / or, the compatibilizer comprises any one or a combination of at least two of ethylene-vinyl acetate copolymer, ethylene-propylene-diene monomer copolymer, or styrene-ethylene-butadiene-styrene copolymer.

[0037] And / or, the antioxidant comprises any one or a combination of at least two of tetrakis[methyl-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol, N,N'-1,6-hexylidene-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], 3,5-di-tert-butyl-4-hydroxyphenyl propionic acid n-octadecyl alcohol, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)trione, triethylene glycol bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate], or 2,2'-methylenebis(4-methyl-6-tert-butylphenol).

[0038] In a fourth aspect, the present application provides use of the flame retardant composition of the third aspect in the preparation of a flame retardant material for household electrical appliances.

[0039] The flame-retardant composition provided by the application can improve the poor flame-retardant performance of polyamide and the easy precipitation of flame retardants used in air ducts and impellers, and has a better application effect.

[0040] Compared with the prior art, the application has the following beneficial effects:

[0041] (1) The preparation method provided by the application realizes slow release and thermal stability improvement of phosphorus-based flame retardants by encapsulating the phosphorus-based flame retardants in MOFs, and forms a dual flame-retardant mechanism of gas phase (free radical capture) and condensed phase (carbon layer protection) by combining the catalytic carbonization and physical barrier effect of phytic acid modified LDH, thereby significantly improving the flame-retardant efficiency;

[0042] (2) The preparation method provided by the application provides intercalation space for the MOFs loaded flame retardants by introducing phytic acid intercalation to expand the interlayer spacing of LDH, and forms a multi-level structure of “LDH interlayer limited MOF”. When heated, the crosslinking of phytic acid and LDH metal ions promotes the formation of a dense carbon layer, and the phosphorus-based flame retardants released by the MOFs further catalyze carbonization, thereby realizing the synergistic optimization of carbon layer quality and stability;

[0043] (3) The phytic acid (biobased) and LDH (without heavy metal ions) introduced by the application can reduce the environmental burden, the encapsulated MOFs solve the defects of easy migration and volatilization of small molecule flame retardants, and the obtained intercalation assembled composite flame retardant has good dispersibility and long-term stability in the polymer matrix, and is suitable for the development of high-performance flame-retardant materials;

[0044] (4) The application introduces the intercalation assembled composite flame retardant based on polyamide or polypropylene as a base material, and obtains a flame-retardant material with excellent flame-retardant performance, which is suitable for air ducts or impeller devices of range hoods;

[0045] (5) The flame-retardant composition provided by the application can also be applied to other household electrical appliances, such as stoves, and other flame-retardant material scenes with flame-retardant requirements. DETAILED DESCRIPTION

[0046] The technical solutions of the application will be further described through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the application and should not be regarded as specific limitations on the application.

[0047] In the existing flame-retardant modification of polyamide or polypropylene materials, the introduced flame retardants have the problem of poor interfacial compatibility, which reduces the mechanical properties of the composite materials, and the small molecule flame retardants also have the defect of easy precipitation. Based on this, the application provides an intercalation assembled composite flame retardant and its application in polyamide and polypropylene materials.

[0048] In a first aspect, the present application provides a preparation method of an intercalation assembled composite flame retardant, the preparation method comprising:

[0049] (1) reacting a metal salt, a phosphorus-based flame retardant and 2-methyl imidazole (2-MI) in a solvent to obtain a MOFs loaded flame retardant;

[0050] (2) mixing a mixed solution of a divalent salt, a trivalent salt, sodium dodecyl benzene sulfonate and phytic acid with an alkaline solution to perform a hydrothermal reaction to obtain a modified LDH;

[0051] (3) reacting the MOFs loaded flame retardant and the modified LDH in the presence of a promoter to obtain the intercalation assembled composite flame retardant.

[0052] In the flame retardant provided by the present application, the introduction of MOFs can effectively prevent the leakage failure of the flame retardant, and at the same time can prevent the premature decomposition of the flame retardant, realize the slow release of the flame retardant, and the introduced phytic acid modified LDH can improve the dispersion uniformity of the flame retardant in the base material, avoid the aggregation and sedimentation of the flame retardant, thereby helping to improve the overall stability and flame retardant performance of the flame retardant. Therefore, the intercalation assembled composite flame retardant provided by the present application has excellent flame retardant performance, good dispersibility and stability in the polymer matrix, is not easy to aggregate, and is not easy to precipitate, which can effectively solve the shortcomings of traditional flame retardants, such as poor flame retardant performance, easy aggregation and poor stability.

[0053] In the present application, for step (1);

[0054] Preferably, the mass ratio of the metal salt, 2-methyl imidazole and phosphorus-based flame retardant is (40-60):(80-100):(20-40), the 40-60 can be 40, 42, 45, 50, 52, 55, 58, 60 or a range between any of the above values, the 80-100 can be 80, 82, 84, 85, 86, 88, 90, 92, 95, 98, 100 or a range between any of the above values, and the 20-40 can be 20, 22, 24, 25, 26, 28, 30, 32, 34, 36, 38, 40 or a range between any of the above values.

[0055] Preferably, the metal salt includes any one or a combination of at least two of zinc salt, copper salt, iron salt, aluminum salt or magnesium salt, and the anion of the metal salt is nitrate ion or chloride ion.

[0056] Preferably, the metal salt can be any one or a combination of at least two of zinc nitrate, copper nitrate, ferrous nitrate or ferric nitrate, aluminum nitrate, magnesium nitrate, aluminum chloride, magnesium chloride and the like.

[0057] Preferably, the phosphorus-based flame retardant comprises any one or a combination of at least two of TCP, TPP, RDP, BDP, DOPO, DOPO-HQ, DOPO-NQ, CEPPA or MPP, preferably CEPPA and / or DOPO.

[0058] Preferably, the reaction in step (1) is carried out under sealed condition, the temperature of the reaction is 65-70℃, for example 65℃, 66℃, 67℃, 68℃, 69℃, 70℃ or a range between any of the above values, and the time is 15-20h, for example 15h, 16h, 17h, 18h, 19h, 20h or a range between any of the above values.

[0059] Preferably, the solvent comprises methanol.

[0060] In the present application, for step (2);

[0061] Preferably, the cation in the divalent salt comprises any one or a combination of at least two of Cu 2+ , Zn 2+ , Ni 2+ or Mg 2+ .

[0062] Preferably, the cation in the trivalent salt comprises Fe 3+ and / or Al 3+ .

[0063] Preferably, the mass ratio of the divalent salt, the trivalent salt, sodium dodecyl benzene sulfonate and phytic acid is 100:(20-70):(10-30):(20-40), the 20-70 can be 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70 or a range between any of the above values, the 10-30 can be 10, 12, 14, 15, 16, 18, 20, 22, 24, 25, 26, 28, 30 or a range between any of the above values, and the 20-40 can be 20, 22, 24, 25, 26, 28, 30, 32, 34, 35, 38, 40 or a range between any of the above values.

[0064] Preferably, the amount of the basic solution added is such that the pH value of the reaction system is 7-10, for example 7, 7.5, 8, 8.5, 9, 9.5, 10 or a range between any of the above values.

[0065] Preferably, the solute used in the basic solution comprises any one or a combination of at least two of urea, ammonia, sodium hydroxide or potassium hydroxide.

[0066] Preferably, the temperature of the hydrothermal reaction is 60-110℃, such as 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, or a range between any of the aforementioned values, and the time is 10-24h, such as 10h, 12h, 14h, 15h, 16h, 18h, 20h, 22h, 24h, or a range between any of the aforementioned values.

[0067] In the present application, for step (3);

[0068] Preferably, the promoter comprises cetyltrimethylammonium bromide (CTAB), and the amount of the promoter added is 1-10% of the mass of the modified LDH, such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or a range between any of the aforementioned values.

[0069] Preferably, the mass ratio of the MOFs supported flame retardant and the modified LDH is 1:(0.8-1), such as 1:0.8, 1:0.82, 1:0.85, 1:0.88, 1:0.9, 1:0.92, 1:0.95, 1:0.98, 1:1, or a range between any of the aforementioned values.

[0070] Preferably, the temperature of the reaction in step (3) is 50-70℃, such as 50℃, 52℃, 55℃, 58℃, 60℃, 62℃, 65℃, 68℃, 70℃, or a range between any of the aforementioned values, and the time is 12-24h, such as 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h, 24h, or a range between any of the aforementioned values.

[0071] In some embodiments of the present application, the preparation method comprises:

[0072] (1) mixing a methanol solution of a metal salt with a methanol solution containing a phosphorus-based flame retardant and 2-methylimidazole, heating to 65-70℃ in a closed environment for 15-20h, centrifuging to obtain a white precipitate, washing, and drying to obtain a MOFs supported flame retardant;

[0073] (2) mixing a divalent salt, a trivalent salt, sodium dodecylbenzenesulfonate, and phytic acid in a solvent, and adding a basic solution to make the pH value of the reaction system 7-10, and performing a hydrothermal reaction at 60-110℃ for 10-24h, filtering, washing, and drying to obtain a modified LDH;

[0074] (3) adding a promoter to a modified LDH solution, then adding a MOFs supported flame retardant suspension, and performing a reaction at 50-70℃ for 12-24h, filtering, washing, and drying to obtain the intercalation assembled composite flame retardant.

[0075] In a second aspect, the present application provides an intercalation assembled composite flame retardant prepared by the preparation method of the first aspect.

[0076] In a third aspect, the present application provides a flame retardant composition comprising, by weight, 70-95 parts of a polymer resin, 5-15 parts of the intercalation assembled composite flame retardant of the second aspect, 10-20 parts of glass fiber, 0.5-4 parts of a toughening agent, 3-8 parts of a compatibilizer, and 0.3-4 parts of an antioxidant.

[0077] In the present application, the polymer resin 70-95 parts can be 70 parts, 72 parts, 75 parts, 78 parts, 80 parts, 82 parts, 85 parts, 88 parts, 90 parts, 92 parts, 95 parts, or a range between any of the above values; the intercalation assembled composite flame retardant 5-15 parts can be 5 parts, 6 parts, 8 parts, 10 parts, 12 parts, 14 parts, 15 parts, or a range between any of the above values, the glass fiber 10-20 can be 10 parts, 12 parts, 14 parts, 15 parts, 16 parts, 18 parts, 20 parts, or a range between any of the above values, the toughening agent 0.5-4 parts can be 0.5 parts, 1 parts, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, or a range between any of the above values, the compatibilizer 3-8 parts can be 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, or a range between any of the above values, and the antioxidant 0.3-4 parts can be 0.3 parts, 0.5 parts, 0.8 parts, 1 parts, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, or a range between any of the above values.

[0078] Preferably, the polymer resin is selected from a polyamide resin and / or a polypropylene resin.

[0079] Preferably, the polyamide resin comprises any one or a combination of at least two of PA6, PA66, PA10, PA11, PA12, PA46, or PA610.

[0080] Preferably, the toughening agent comprises any one or a combination of at least two of ethylene-propylene copolymer, ethylene-hexene copolymer, ethylene-butene copolymer, ethylene-octene copolymer, styrene-butadiene-styrene copolymer, or hydrogenated styrene-butadiene-styrene copolymer.

[0081] Preferably, the compatibilizer comprises any one or a combination of at least two of ethylene-vinyl acetate copolymer (EVA), ethylene-propylene-diene monomer copolymer (EPDM), or styrene-ethylene-butadiene-styrene copolymer (SEBS).

[0082] Preferably, the antioxidant comprises any one of or a combination of at least two of pentaerythritol tetrakis[methyl-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), N,N'-1,6-hexanediyl-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide] (antioxidant 1098), n-octadecyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate (antioxidant 1076), 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)trione (antioxidant 1790), triethylene glycol bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate] (antioxidant 245), or 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (antioxidant 2246).

[0083] The present application also provides a preparation method of the flame-retardant composition, the preparation method comprising: mixing, melt-extruding, and cooling granulating the components to obtain the flame-retardant composition.

[0084] Preferably, the preparation method comprises:

[0085] (1) drying each component separately under vacuum at 40-100°C (for example, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, or a range between any of the aforementioned values) for 1-10h, for example, 1h, 2h, 4h, 5h, 6h, 8h, 10h, or a range between any of the aforementioned values;

[0086] (2) mixing the components for 2-10min, for example, 2min, 4min, 5min, 6min, 8min, 10min, or a range between any of the aforementioned values;

[0087] (3) The mixture is melt-extruded and granulated using a screw extruder, wherein the rotation speed is 60-150 rpm, for example 60 rpm, 70 rpm, 80 rpm, 90 rpm, 100 rpm, 110 rpm, 120 rpm, 130 rpm, 140 rpm, 150 rpm or any value between the above; the temperature of the first zone is 205-215℃, for example 205℃, 206℃, 208℃, 210℃, 212℃, 215℃ or any value between the above; and the temperature of the second zone is 215-225℃, for example 215℃, 216℃, 218℃, 220℃, 2... The temperature range of the third zone is 220-230℃, such as 220℃, 222℃, 224℃, 225℃, 226℃, 228℃, 230℃, or any of the above values. The temperature range of the fourth zone is 210-220℃, such as 210℃, 212℃, 214℃, 215℃, 216℃, 218℃, 220℃, or any of the above values. The temperature range of the die head is 190-210℃, such as 190℃, 195℃, 198℃, 200℃, 202℃, 205℃, 208℃, 210℃, or any of the above values.

[0088] Fourthly, the present invention provides the application of the flame-retardant composition described in the third aspect in the preparation of flame-retardant materials for household appliances.

[0089] Preferably, the flame-retardant composition is used in the preparation of range hood impellers or ducts.

[0090] The flame-retardant composition provided by this invention can improve the shortcomings of poor flame-retardant performance and easy precipitation of flame retardants in polyamide used in air ducts and impellers, and has better application effect.

[0091] The following explanation is provided through specific examples:

[0092] Unless otherwise specified, the raw materials involved in the following specific embodiments of the present invention are all conventional materials in the art, and can be purchased from commercially available products. Some raw material information is shown in Table 1:

[0093] Table 1

[0094]

[0095] Preparation Examples 1-7

[0096] This preparation example provides an intercalation-assembled composite flame retardant and its preparation method. The mass fractions of each raw material are shown in Table 2.

[0097] Table 2

[0098]

[0099]

[0100] The preparation method is as follows:

[0101] (1) The metal salt is dissolved in 100 parts of methanol solvent and ultrasonicated until transparent; 500 parts of methanol solvent is heated to 40°C, and a phosphorus-based flame retardant and 2-methylimidazole are sequentially added for dissolution. After complete dissolution, the metal salt solution is added, magnetic stirring is started for 5 min, and then the reaction is carried out in a high-pressure reaction kettle with a polytetrafluoroethylene liner. After the reaction is completed, cooling, centrifugation, washing (with methanol), and drying are performed to obtain a MOFs loaded flame retardant;

[0102] (2) 5000 parts of distilled water is used to dissolve divalent salt, trivalent salt, sodium dodecylbenzenesulfonate, and phytic acid, and a urea solution is added to adjust the pH value of the reaction system, and a hydrothermal reaction is carried out. After the reaction is completed, filtration, washing (with distilled water), and drying are performed to obtain a modified LDH;

[0103] (3) The MOFs loaded flame retardant is dispersed in 800 parts of 50% ethanol aqueous solution to obtain a suspension, and the modified LDH is dispersed in 800 parts of 50% ethanol aqueous solution to obtain a colloidal solution. Then, a promoter is added and mixed, and the suspension is added under stirring to carry out a reaction. After the reaction, filtration, washing (with distilled water and ethanol alternately), drying, and grinding are performed to obtain an intercalation assembled composite flame retardant.

[0104] Comparative Preparation Example 1

[0105] The present comparative preparation example provides a composite flame retardant and a preparation method thereof.

[0106] The difference from Preparation Example 1 is that only step (2) is carried out in the present comparative preparation example, and 30 parts of CEPPA is added in step (2), specifically as follows:

[0107] In 5000 parts of distilled water, divalent salt, trivalent salt, sodium dodecylbenzenesulfonate, phytic acid, and CEPPA are added, and a urea solution is added to adjust the pH value of the reaction system, and a hydrothermal reaction is carried out. After the reaction is completed, filtration, washing (with distilled water), and drying are performed to obtain a composite flame retardant (SDS-PA / CEPPA-LDH, denoted as Fr p 1).

[0108] Comparative Preparation Example 2

[0109] The present comparative preparation example provides a composite flame retardant and a preparation method thereof.

[0110] The difference from Preparation Example 1 is that in the present comparative preparation example, phytic acid is not added in step (2), i.e., the LDH is not modified with phytic acid, and the obtained composite flame retardant is SDS-ZIF@CEPPA-LDH, denoted as Frp 2.

[0111] This comparative preparation example provides a composite flame retardant and a preparation method thereof.

[0112] This comparative preparation example provides a composite flame retardant and a preparation method thereof.

[0113] The difference from Preparation Example 1 is that in this comparative preparation example, steps (2)-(3) are not performed, i.e., directly using the MOFs supported flame retardant as the composite flame retardant ZIF@CEPPA, denoted as Fr p 3.

[0114] Comparative Preparation Example 4

[0115] This comparative preparation example provides a composite flame retardant and a preparation method thereof.

[0116] The difference from Preparation Example 1 is that in this comparative preparation example, steps (1), (3) are not performed, i.e., directly using the modified LDH as the composite flame retardant SDS-PA-LDH, denoted as Fr p 4.

[0117] Comparative Preparation Example 5

[0118] This comparative preparation example provides a flame retardant, which is CEPPA, denoted as Fr p 5.

[0119] Examples 1-5 and Comparative Examples 1-2

[0120] This example provides a flame-retardant composition and a preparation method thereof, and the specific components are shown in Table 3:

[0121] Table 3

[0122]

[0123] The preparation method is as follows:

[0124] (1) After drying each component at 80°C under vacuum for 5h, mix in a high-speed mixer for 8min;

[0125] (2) The mixture is melt-extruded and granulated using a screw extruder, wherein the rotation speed is 100rpm, the first zone temperature is 210°C, the second zone temperature is 220°C, the third zone temperature is 225°C, the fourth zone temperature is 215°C, and the die temperature is 200°C.

[0126] Examples 6-11

[0127] This example provides a flame-retardant composition.

[0128] The difference from Example 1 is that, in the present example, the composite flame retardant is the composite flame retardant (Fr2-Fr7) provided by Preparation Example 2-7, respectively.

[0129] Comparative Examples 3-7

[0130] The present comparative example provides a flame-retardant composition.

[0131] The difference from Example 1 is only that, in the present comparative example, the flame retardant is replaced by the flame retardant provided by Comparative Preparation Examples 1-5.

[0132] Comparative Example 8

[0133] The present comparative example provides a composition.

[0134] The difference from Example 1 is only that, in the present comparative example, no flame retardant is added.

[0135] Performance test

[0136] The samples provided by the examples and comparative examples are subjected to performance test, in the following manner:

[0137] (1) Limiting oxygen index (LOI): tested according to the provisions of GB / 8624-2012;

[0138] (2) Vertical burning performance: tested according to the provisions of “Flame Retardant Performance Test Method-Vertical Burning Method” (GB2409-84);

[0139] (3) Residual carbon value: American TA (MDSCQ100) thermal gravimetric analyzer is used, air atmosphere heating rate is 10℃ / min, and the temperature range is 30-700℃;

[0140] (4) Tensile strength: tested according to the provisions of GB / T 1040;

[0141] (5) Double 85 test: 85℃, 85% humidity test for 1000h, and whether small molecule particles are precipitated on the surface of the material is observed;

[0142] The test results are shown in Table 4:

[0143] Table 4

[0144]

[0145]

[0146] As can be seen from the examples and performance test, the intercalation assembled composite flame retardant provided by the present application can effectively improve the flame retardant performance of the polymer matrix when introduced into the polymer matrix, and the composite flame retardant has good dispersibility and stability, and is not easy to migrate and precipitate, and is suitable for the development of high-performance flame-retardant materials.

[0147] It can be seen from the comparison of Examples 1, 9 and Examples 10-11 that when the mass ratio of the MOFs loaded flame retardant and the modified LDH is 1:(0.8-1) in the preparation of the intercalation assembled composite flame retardant, the obtained intercalation assembled composite flame retardant has the best flame retardant effect.

[0148] It can be seen from the comparison of Examples 2 and Comparative Example 1, and Examples 5 and Comparative Example 2 that when the addition amount of the intercalation assembled composite flame retardant is 5-15 parts by weight in the flame retardant composition, the flame retardant effect is the best and the mechanical properties of the material are not reduced.

[0149] It can be seen from the comparison of Examples 1 and Comparative Example 3 that the preparation method provided by the present application can avoid the shortcoming of decomposition and release of phosphorus-based flame retardants at high temperature by encapsulating the phosphorus-based flame retardants with MOFs.

[0150] It can be seen from the comparison of Examples 1 and Comparative Example 4 that the modification of LDH with phytic acid introduced in the present application can ensure that the flame retardant has a relatively optimal flame retardant effect, and the reason for the poor flame retardant effect of Comparative Example 2 is that the interlayer spacing of LDH is relatively small, and the MOFs loaded flame retardant cannot fully enter the interlayer of LDH.

[0151] It can be seen from the comparison of Examples 1 and Comparative Example 5 that the use of MOFs loaded flame retardant alone has a relatively low flame retardant effect on the polymer matrix, and the possible reason is that the MOFs loaded flame retardant is prone to agglomeration.

[0152] It can be seen from the comparison of Examples 1 and Comparative Example 6 that the use of modified LDH alone has a relatively low flame retardant effect on the polymer matrix.

[0153] It can be seen from the comparison of Examples 1 and Comparative Example 7 that the use of CEPPA alone as a flame retardant is prone to release at high temperature.

[0154] The applicant declares that the technical solutions of the present application are illustrated by the above examples, but the present application is not limited to the above examples, that is, it does not mean that the present application must rely on the above examples to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of each raw material of the product of the present application, addition of auxiliary ingredients, selection of specific methods, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for preparing an intercalated composite flame retardant, characterized in that, The preparation method includes: (1) Metal salts react with phosphorus-based flame retardants to obtain MOFs-supported flame retardants; (2) Modified LDH was obtained by using phytic acid to modify LDH; (3) The MOFs-supported flame retardant and the modified LDH are reacted to obtain the intercalated composite flame retardant.

2. The preparation method according to claim 1, characterized in that, Step (1) includes reacting a metal salt, a phosphorus-based flame retardant and 2-methylimidazole in a solvent to obtain a MOF-supported flame retardant.

3. The preparation method according to claim 2, characterized in that, The mass ratio of the metal salt, 2-methylimidazole and phosphorus flame retardant is (40-60):(80-100):(20-40); And / or, the metal salt includes any one or a combination of at least two of zinc salt, copper salt, iron salt, aluminum salt or magnesium salt, and the anion of the metal salt is nitrate ion or chloride ion; And / or, the phosphorus-based flame retardant includes any one or a combination of at least two of TCP, TPP, RDP, BDP, DOPO, DOPO-HQ, DOPO-NQ, CEPPA, or MPP; And / or, the reaction in step (1) is carried out under sealed conditions, at a temperature of 65-70°C, for a time of 15-20 hours.

4. The preparation method according to claim 1, characterized in that, Step (2) includes: mixing a mixed solution of divalent salt, trivalent salt, sodium dodecylbenzenesulfonate and phytic acid with an alkaline solution to carry out a hydrothermal reaction to obtain the modified LDH.

5. The preparation method according to claim 4, characterized in that, The cations in the divalent salt include Cu. 2+ Zn 2+ Ni 2+ or Mg 2+ Any one or at least two of them; And / or, the cations in the trivalent salt include Fe 3+ and / or Al 3+ ; And / or, the mass ratio of the divalent salt, trivalent salt, sodium dodecylbenzenesulfonate and phytic acid is 100:(20-70):(10-30):(20-40); And / or, the amount of alkaline solution added is such that the pH of the reaction system is 7-10; And / or, the solute used in the alkaline solution includes any one or a combination of at least two of urea, ammonia, sodium hydroxide, or potassium hydroxide; And / or, the hydrothermal reaction is carried out at a temperature of 60-110°C for a time of 10-24 hours.

6. The preparation method according to claim 1, characterized in that, The reaction in step (3) is carried out in the presence of a promoter, which includes hexadecyltrimethylammonium bromide, and the amount of the promoter added is 1-10% of the mass of the modified LDH; And / or, the mass ratio of the MOFs-supported flame retardant to the modified LDH is 1:(0.8-1); And / or, the reaction in step (3) is carried out at a temperature of 50-70°C for 12-24 hours.

7. An intercalation-assembled composite flame retardant prepared by the preparation method according to any one of claims 1-6.

8. A flame-retardant composition, characterized in that, By weight, it comprises 70-95 parts polymer resin, 5-15 parts intercalation assembly composite flame retardant as described in claim 7, 10-20 parts glass fiber, 0.5-4 parts toughening agent, 3-8 parts compatibilizer and 0.3-4 parts antioxidant.

9. The flame-retardant composition according to claim 8, characterized in that, The polymer resin is selected from polyamide resin and / or polypropylene resin; And / or, the toughening agent includes any one or a combination of at least two of ethylene-propylene copolymer, ethylene-hexene copolymer, ethylene-butene copolymer, ethylene-octene copolymer, styrene-butadiene-styrene copolymer or hydrogenated styrene-butadiene-styrene copolymer; And / or, the compatibilizer includes any one or a combination of at least two of ethylene-vinyl acetate copolymer, ethylene-propylene-diene monomer copolymer, or styrene-ethylene-butadiene-styrene copolymer; And / or, the antioxidant comprises pentaerythritol tetrakis[methyl-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N′-1,6-hexylene-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], n-octadecyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)trione, triethylene glycol bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate], or 2,2′-methylenebis(4-methyl-6-tert-butylphenol], or any one or a combination of at least two of these.

10. The use of the flame-retardant composition of claim 8 or 9 in the preparation of flame-retardant materials for household appliances.

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