A hyperbranched flame retardant containing MOFs and its preparation method

Abstract

The present invention provides a nitrogen-containing hyperbranched flame retardant containing MOFs and a preparation method thereof. Using specific MOFs, diamino compounds and triglycidyl cyanurate as the hyperbranched basic structure, it overcomes the disadvantages of poor compatibility with the matrix, low flame retardancy efficiency, and loss during use of additive flame retardants. When flame-retarding high polymers, a small amount of the hyperbranched flame retardant containing MOFs is compounded with a phosphorus-containing flame retardant, and a relatively high flame retardant effect is achieved due to the intumescent flame retardant effect and the synergistic catalytic effect. The hyperbranched flame retardant containing MOFs provided by the present invention has a relatively high flame retardancy efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of flame retardants, and in particular to a MOFs-containing hyperbranched flame retardant, a preparation method thereof, and an application thereof. Background Art

[0002] Triglycidyl isocyanurate (TGIC) is a heterocyclic polyepoxide compound, which has good heat resistance, weather resistance, adhesiveness, and excellent high-temperature performance. TGIC is mainly used as a curing agent for carboxyl polyester and carboxyl acrylic resin powder coatings, and high-purity TGIC is usually used to manufacture adhesives, electrical insulating laminates, plastic stabilizers, etc. Due to the high nitrogen content and characteristic epoxy groups of TGIC, TGIC is widely used as a precursor of nitrogen-containing compounds in the preparation of intumescent flame retardants.

[0003] Metal-organic frameworks (MOFs) are ordered crystal frameworks generated by the self-assembly of metal ions and organic ligands. Due to their large specific surface area, regular pore structure, and adjustable surface chemical properties, they are widely used in fields such as gas storage, catalysis, separation, and drug delivery. In recent years, due to the high thermal stability of MOF materials, they have been widely used as new flame retardants for various polymers. MOF has a rich variety of transition metals, flame retardant elements, and potential carbon sources, and its structure and properties are easy to adjust, making MOF and its derivatives and MOF hybrids promising for flame retardant research. Based on the modification strategy of MOF, combining MOFs (metal-organic framework materials) with a gas source at the nanoscale level, this review is very beneficial for researchers to quickly master the latest developments in this field.

[0004] Hyperbranched polymers are macromolecules with a highly three-dimensional structure and highly branched. The intumescent flame retardants of hyperbranched polymers in the prior art have problems such as low nitrogen content, weak carbon-forming ability, and low flame retardant efficiency. Therefore, introducing the MOFs structure into hyperbranched flame retardants is expected to solve the above problems of current flame retardants.

[0005] The Chinese invention patent announcement text CN104262680B discloses a hyperbranched intumescent flame retardant and a preparation method thereof, which uses phthalic anhydride and diethanolamine, etc. to react to obtain AB 2 monomers, which improves the flame retardant efficiency of the flame retardant, but its component setting does not include MOFs and is not optimized enough. Summary of the Invention

[0006] The present invention provides a MOFs-containing hyperbranched flame retardant, a preparation method thereof, and an application thereof.

[0007] To solve the above technical problems, the present invention is realized through the following technical solutions:

[0008] A MOF-containing hyperbranched flame retardant, the MOF-containing hyperbranched flame retardant having the structure shown in Formula I:

[0009]

[0010] In Formula I, Y is -NH- or -N-, and R is a piperazine ring or a branched alkylene group, aryl group, or polycyclic aromatic group containing 1 to 30 carbon atoms. is an extension of the hyperbranched structure, and ō is a MOF structure containing an amino group.

[0011] A method for preparing a MOF-containing hyperbranched flame retardant, the MOF-containing hyperbranched flame retardant being the above-mentioned MOF-containing hyperbranched flame retardant, and the preparation method comprising the following steps:

[0012] (1) In an inert gas environment, dissolve a diamine compound in a polar organic solvent, then add a catalyst, and then heat to 70 - 150 °C.

[0013] (2) Dissolve triglycidyl isocyanurate in a polar organic solvent, and then slowly add it to the mixed solution obtained in step (1). Under the protection of an inert gas, carry out a ring-opening reaction and maintain a ring-opening reaction temperature of 80 °C - 150 °C, and react for 8 - 24 h under stirring conditions to obtain a nitrogen-containing hyperbranched flame retardant.

[0014] (3) Add a MOF material containing an amino group to the nitrogen-containing hyperbranched flame retardant obtained in step (2), and continuously stir for 8 - 24 h to carry out a capping reaction; then add a precipitant, and after carrying out solid-liquid separation, washing with water, and drying steps, obtain a MOF-containing hyperbranched flame retardant having the structure shown in Formula I and containing a MOF structure.

[0015] Preferably, the diamine compound is one or a mixture of several of piperazine, ethylenediamine, hydroxyethyl ethylenediamine, 3,3-diaminodiphenyl sulfone, diethyltoluenediamine, 2,6-toluenediamine, N-aminoethylpiperazine, N,N-dimethyl-1,3-propanediamine, diaminodiphenylmethane, or diaminodiphenyl sulfone.

[0016] Preferably, the catalyst is one of N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether, N,N,N',N'-tetramethylalkylenediamine, N,N-dimethylbenzylamine, triethylamine, N-ethylmorpholine, N,N'-diethylpiperazine, N,N'-dimethylpyridine, or pyridine.

[0017] Preferably, the MOF structure containing an amino group is an ammonia-containing metal-organic framework material, which is NH 2 -UiO-66(Zr), NH 2 -UiO-66(Hf), NH 2-MIL-53(Fe), NH 2 -MIL-101(Fe), NH 2 -MIL-53(Al), NH 2 -MIL-101(Al), NH 2 -MIL-101(Cr) or NH 2 -MIL-125(Ti), one or more of them; the capping reaction is achieved by the epoxy ring-opening reaction of the amino group to cap the hyperbranched flame retardant.

[0018] Preferably, the polar organic solvent is acetonitrile, dichloroethane, chloroform, dimethylformamide or dimethyl sulfoxide.

[0019] Preferably, the molar ratio of the triglycidyl isocyanurate to the diamine compound is (2.5 - 10):(1 - 2); the mass ratio of the triglycidyl isocyanurate + diamine compound to the amino group-containing MOFs material is (3 - 5):1.

[0020] Preferably, the inert gas is one or more of nitrogen, argon or helium.

[0021] Preferably, the precipitant in step (3) is water. The reaction product obtained from the capping reaction is precipitated with water, and then successively subjected to solid-liquid separation, washing with water and drying to obtain the nitrogen-containing hyperbranched flame retardant having the structure shown in Formula I.

[0022] An application method of the MOFs-containing hyperbranched flame retardant, specifically the application of the above-mentioned MOFs-containing hyperbranched flame retardant in the field of flame retardancy.

[0023] In the present invention, when the diamine compound and MOFs are in a mixture, there is no special limitation on the proportion of each substance in the mixture except as specifically defined in the present invention, and mixtures in any proportion can be used. Except as specifically defined, there is no special limitation on the source of the diamine compound in the present invention, and commercially available products well-known to those skilled in the art can be used.

[0024] In the present invention, the principle of the ring-opening reaction is as follows reaction equation:

[0025]

[0026] In the above reaction equation, Y is -NH- or -N-, R is a piperazine ring or a branched alkylene group, aryl group, polycyclic aromatic group containing 1 - 30 carbon atoms, and ō is the MOFs structure containing an amino group.

[0027] After precipitation is completed, the present invention separates the solid and liquid in the precipitated system to obtain a solid product. The present invention has no special limitation on the specific manner of solid-liquid separation, and any solid-liquid separation manner well-known to those skilled in the art can be adopted, specifically, such as filtration.

[0028] After obtaining the solid product, the present invention preferably washes the solid product to obtain a washed product. The present invention has no special limitation on the number of washing times and the amount of water used.

[0029] After obtaining the aqueous product, the present invention preferably dries the washed product to obtain a nitrogen-containing hyperbranched flame retardant. The present invention has no special limitation on the specific manner of the drying, and any drying manner well-known to those skilled in the art can be adopted. Specifically, the drying is preferably vacuum drying at 50 °C for 2 - 10 h.

[0030] The present invention also provides the application of the MOFs-containing hyperbranched flame retardant described in the above technical solution or the MOFs-containing hyperbranched flame retardant prepared by the preparation method described in any one of the above technical solutions in the field of flame retardancy, and more preferably in flame retardant resins.

[0031] In the present invention, the mass fraction of the MOFs-containing hyperbranched flame retardant in the polymer material is preferably 5 - 15%.

[0032] The beneficial effects of the present invention are as follows:

[0033] The present invention forms a nitrogen-containing hyperbranched flame retardant containing MOFs by specifically setting a core new structure with an amino group-containing MOFs material, so that the flame retardant level of the formed flame retardant material can basically reach the V0 level (at least above V1), and the limiting oxygen index (LOI) can even reach above 32, and the better implementation mode can reach above 37 (the conventional limiting oxygen index (LOI) of polyolefin materials is 21), thereby greatly improving the flame retardant performance.

[0034] The preparation method specifically set by the present invention has mild reaction conditions, is easy to implement in the preparation process, and can endow the polymer material with good flame retardant performance. The characteristic of the high nitrogen content of the hyperbranched flame retardant enables it to be used as a good gas source and synergistic flame retardant for intumescent flame retardants, and has an efficient flame retardant effect in materials such as epoxy resins and polyolefins. Specific Embodiments

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] The present invention provides a hyperbranched flame retardant containing MOFs, its preparation method and application, which will be described in detail below in conjunction with embodiments. However, they should not be construed as limiting the scope of protection of the present invention.

[0037] Example 1

[0038] Dissolve 0.52 mol of anhydrous piperazine in 250 ml of acetonitrile and add it to a 500 mL three-necked flask equipped with a reflux condenser, a constant pressure dropping funnel, and a stirrer. Add 0.01 mol of triethylamine, heat the system to 85 °C, then dissolve 0.25 mol of triglycidyl isocyanurate (TAIC) in 100 mL of acetonitrile and add it dropwise to the above system. Under nitrogen protection, adjust and maintain the temperature at 85 °C and keep mechanical stirring for 8 hours. Add 25 g of NH 2 -MIL-101(Fe), continue stirring for 8 hours, then add 200 mL of water as a precipitant, stop stirring, filter while it is hot, wash with water 3 times, and dry in vacuum at 90 °C for 8 hours to obtain a hyperbranched flame retardant containing MOFs.

[0039] Comparative Example 1

[0040] This comparative example does not have the step of adding "NH 2 -MIL-101(Fe)", and other steps are the same as those in Example 1. The obtained results are compared as shown in Table 2.

[0041] Example 2

[0042] Dissolve 0.5 mol of ethylenediamine in 300 mL of dimethyl sulfoxide and add it to a 500 mL three-necked flask equipped with a reflux condenser, a constant pressure dropping funnel, and a stirrer. Add 0.01 mol of triethylamine, heat the system to 120 °C, then dissolve 0.20 mol of triglycidyl isocyanurate (TAIC) in 100 mL of dimethylformamide and add it dropwise to the above system. Under nitrogen protection, maintain the temperature at 120 °C and adjust stirring for 10 hours. Add 15 g of NH 2 -MIL-125(Ti), continue stirring for 10 hours, add 100 mL of water as a precipitant, stop stirring, filter while it is hot, wash with water 6 times, and dry in vacuum at 80 °C for 8 hours to obtain a hyperbranched flame retardant containing MOFs.

[0043] Comparative Example 2

[0044] This comparative example does not have the step of adding "NH 2 -MIL-125(Ti)", and other steps are the same as those in Example 2. The obtained results are compared as shown in Table 2.

[0045] Example 3

[0046] Dissolve 0.5 mol of diaminodiphenylmethane in 300 mL of chloroform and add it to a 500 mL three-necked flask equipped with a reflux condenser, a constant pressure dropping funnel, and a stirrer. Add 0.01 mol of N,N-dimethylcyclohexylamine, heat the system to 70 °C, then dissolve 0.25 mol of triglycidyl isocyanurate in 100 ml of chloroform and dropwise add it to the above system. Keep the temperature at 80 °C under nitrogen protection and stir continuously for 8 hours. Add 15 g of NH 2 -MIL-125(Ti), stir continuously for 10 hours, add 150 ml of water as a precipitant, stop stirring, filter while it is hot, wash with water 4 times, and dry in vacuum at 80 °C for 8 hours to obtain a MOFs hyperbranched flame retardant.

[0047] Comparative Example 3

[0048] This comparative example does not include the step of adding "NH 2 -MIL-125(Ti)", and other steps are the same as those in Example 3. The obtained results are compared as shown in Table 2.

[0049] To investigate the flame retardant effect of the MOFs hyperbranched flame retardant of the present invention, a flammable epoxy resin was selected as the matrix. The flame retardants prepared in Example 1, Example 2, and Example 3 were added to the epoxy resin according to the ratio in Table 1. After mixing evenly, it was poured into a mold and thermally cured to prepare standard samples. The flame retardant properties of the standard samples were tested according to the UL94 test standard (SATMD3801-10) and the LOI test standard (ASRM D2863-06A), and the test results are shown in Table 1.

[0050] Table 1

[0051]

[0052]

[0053] In the typical preparation processes of Comparative Example 1, Comparative Example 2, and Comparative Example 3, the preparation step of adding the MOFs flame retardant was not included, and a conventional nitrogen-containing hyperbranched flame retardant without MOFs was obtained. In the same way as in Table 1, the flame retardants prepared in Comparative Example 1, Comparative Example 2, and Comparative Example 3 were added to the epoxy resin according to the ratio in Table 2 (the corresponding ratio method is corresponding to Table 1). After mixing evenly, it was poured into a mold and thermally cured to prepare standard samples. The flame retardant properties of the standard samples were tested according to the UL94 test standard (SATM D3801-10) and the LOI test standard (ASRM D2863-06A), and the test results are shown in Table 2.

[0054] Table 2

[0055]

[0056] As can be seen from Table 1 and Table 2, the flame retardant prepared by the present invention has mild reaction conditions, and the preparation process is simple and easy. At the same time, it can endow the polymer material with good flame retardant properties. A kind of MOFs-containing hyperbranched flame retardant prepared by the preparation method of the present invention was mixed with APP in the ratio of 1:2 and 2:1 respectively in each example to form a flame retardant material for comparison. When added to the flame retardant material in the same proportion, its LOI value is higher than that of the LOI value in Table 2 without adding MOFs. This indicates that adding appropriate MOFs materials to the flame retardant of the present invention improves its flame retardancy.

Claims

1. Preparation method of MOFs-containing hyperbranched flame retardant, characterized in that, the MOFs-containing hyperbranched flame retardant has the structure shown in Formula I: In formula I, Y is -NH- or -N-, and R is a piperazine ring or a branched alkylene group, aryl group, or polycyclic aromatic group containing 1 to 30 carbon atoms. It is an extension of the hyperbranched structure, and ō is an MOF structure containing an amino group. The preparation method comprises the following steps: (1) In an inert gas environment, dissolve the diamine compound in a polar organic solvent, then add a catalyst, and then heat to 70-150 °C; (2) Dissolve triglycidyl isocyanurate in a polar organic solvent, and then slowly add it to the mixed solution obtained in step (1). Under the protection of inert gas, carry out a ring-opening reaction and maintain the ring-opening reaction temperature of 80 °C - 150 °C, and react for 8-24 h under stirring conditions to obtain a nitrogen-containing hyperbranched flame retardant; (3) Add an amino group-containing MOFs material to the nitrogen-containing hyperbranched flame retardant obtained in step (2), and continuously stir for 8-24 h to carry out a capping reaction; then add a precipitant, and after solid-liquid separation, washing with water and drying steps, obtain a MOFs-containing hyperbranched flame retardant with the structure shown in Formula I; The amino-containing MOF structure is an amino-functionalized metal-organic framework material, namely NH 2 -UiO-66(Zr), NH 2 -UiO-66(Hf), NH 2 -MIL-53(Fe), NH 2 -MIL-101(Fe), NH 2 -MIL-53(Al), NH 2 -MIL-101(Al), NH 2 -MIL-101(Cr) or NH 2 -MIL-125(Ti), one or more of them; the capping reaction is achieved by the epoxy ring-opening reaction of the amino group to cap the hyperbranched flame retardant.

2. The preparation method according to claim 1, characterized in that, the diamine compound is one or a mixture of several of piperazine, ethylenediamine, hydroxyethyl ethylenediamine, 3,3-diaminodiphenyl sulfone, diethyltoluenediamine, 2,6-toluenediamine, N-aminoethylpiperazine, N,N-dimethyl-1,3-propanediamine, diaminodiphenylmethane or diaminodiphenyl sulfone.

3. The preparation method according to claim 1, characterized in that, the catalyst is one of N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether, N,N,N',N'-tetramethylalkylenediamine, N,N-dimethylbenzylamine, triethylamine, N-ethylmorpholine, N,N'-diethylpiperazine, N,N'-dimethylpyridine or pyridine.

4. The preparation method according to claim 1, characterized in that, the polar organic solvent is acetonitrile, dichloroethane, chloroform, dimethylformamide or dimethyl sulfoxide.

5. The preparation method according to claim 4, characterized in that, the molar ratio of triglycidyl isocyanurate to diamine compound is (2.5-10):(1-2); the mass ratio of triglycidyl isocyanurate + diamine compound to the amino group-containing MOFs material is (3-5):

1.

6. The preparation method according to claim 4, characterized in that, the inert gas is one or more of nitrogen, argon or helium.

7. The preparation method according to claim 1, characterized in that, the precipitant in step (3) is water. Precipitate the reaction product obtained from the capping reaction with water, and then successively carry out solid-liquid separation, washing with water and drying to obtain a MOFs-containing hyperbranched flame retardant with the structure shown in Formula I.

8. Application method of nitrogen-containing hyperbranched flame retardant, characterized in that, application of the MOFs-containing hyperbranched flame retardant prepared by the preparation method according to any one of claims 1-7 in the field of flame retardancy.

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