A rare earth flame retardant synergist and its preparation method and application

Abstract

The present invention belongs to the field of flame retardancy. The present invention provides a rare earth flame retardant synergist and a preparation method and application thereof, comprising the following steps: at room temperature, dissolving Re(NO)3·6H2O in deionized water to form solution A; at room temperature, adding phytic acid PA to deionized water to form solution B, adding a piperazine derivative to solution B until the piperazine derivative is completely dissolved to obtain solution C; at room temperature, adding solution A dropwise to solution C to prepare a solid product; and drying to obtain the rare earth flame retardant synergist. The rare earth flame retardant synergist of the present invention has excellent flame retardant synergistic performance, effectively improves the flame retardant efficiency of phosphorus nitrogen flame retardants, and reduces the amount of flame retardant added. The preparation method of the rare earth flame retardant synergist of the present invention is simple and low in cost. It can be applied to many fields such as automobiles, agricultural films, building materials, and aerospace, effectively improving the flame retardant properties of polymer products, and achieving a balance between mechanical properties and flame retardant properties.

Description

Technical Field

[0001] The invention relates to the field of flame retardant technology, and in particular to a rare earth flame retardant synergist and a preparation method and application thereof. Background Art

[0002] Polypropylene (PP) is a widely used polymer material with good mechanical properties, easy processing, heat resistance, and corrosion resistance. It is widely used in many fields such as automobiles, construction, furniture, and aerospace. However, like most polymer materials, polypropylene is extremely flammable and can easily cause safety hazards. When used, flame retardants are often added to it to improve its flame retardant properties.

[0003] At present, nitrogen-phosphorus intumescent flame retardants represented by ammonium polyphosphate / pentaerythritol compositions and a series of metal hydroxides are two commonly used flame retardants for polypropylene materials. However, the flame retardant efficiency of these two flame retardants is low, and a higher amount of addition is often required to meet the use requirements, which not only increases the cost, but also has a great negative impact on the processing performance and mechanical properties of the product.

[0004] Therefore, researchers are trying to add a third component to the traditional flame retardant system to act as a flame retardant synergist to improve the flame retardant efficiency. While improving the flame retardant effect, it also reduces the total amount of flame retardant added and reduces manufacturing costs. Summary of the invention

[0005] The purpose of the present invention is to provide a rare earth flame retardant synergist and its preparation method and application. The rare earth flame retardant synergist of the present invention has excellent flame retardant synergistic performance, effectively improves the flame retardant efficiency of phosphorus nitrogen flame retardants, and reduces the amount of flame retardant added.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A rare earth flame retardant synergist, the structural formula of which is:

[0008]

[0009] Among them, PA is phytic acid, PI is piperazine, and Re is a rare earth element;

[0010] PI-NH2 + / NH3 + It is a piperazine derivative, and its raw material structural formula is:

[0011] or

[0012] Among them, R 1-6 are independently selected from a hydrogen atom or an alkyl group.

[0013] As a further embodiment of the present invention: Re is selected from one or more of Ce, La, Y, Nd, Sm, Eu, Gd, Dy and Tb.

[0014] A method for preparing a rare earth flame retardant synergist comprises the following steps:

[0015] S1. At room temperature, Re(NO)3·6H2O was dissolved in deionized water to form solution A;

[0016] S2. At room temperature, phytic acid PA is added to deionized water to form solution B, and a piperazine derivative is added to solution B until the piperazine derivative is completely dissolved to obtain solution C;

[0017] S3. At room temperature, solution A was added dropwise to solution C while stirring continuously. After the addition was completed, the mixture was allowed to mature for 0.5 h at room temperature, centrifuged, the precipitate was collected, and washed repeatedly until it was neutral to obtain a solid product.

[0018] S4, the above solid product at 60 o C and vacuum dried to constant weight to obtain the rare earth flame retardant synergist.

[0019] As a further solution of the present invention: in the solution A, the ratio of Re(NO3)3·6H2O to deionized water is 10-50mmol:10-50mL; in the solution C, the ratio of the piperazine derivative to deionized water is 1-5mmol:10-50mL.

[0020] As a further solution of the present invention: the molar ratio of the phytic acid, Re(NO3)3·6H2O and the piperazine derivative is 1:1:1-3.

[0021] An application of a rare earth flame retardant synergist, such as the rare earth flame retardant synergist is applied to polypropylene materials for agricultural films, building materials and automobile parts to obtain flame retardant polypropylene materials.

[0022] As a further solution of the present invention: the flame retardant polypropylene material includes the following raw materials: rare earth synergistic flame retardant, polypropylene, halogen-free flame retardant and antioxidant.

[0023] As a further embodiment of the present invention: the halogen-free flame retardant is selected from at least one of ammonium polyphosphate, ammonium polyphosphate / pentaerythritol composition, melamine phosphate, melamine polyphosphate, melamine cyanurate, metal hypophosphite, piperazine pyrophosphate derivatives, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and its derivatives.

[0024] As a further embodiment of the present invention: the antioxidant is selected from at least one of antioxidant 1010 and antioxidant 168.

[0025] As a further solution of the present invention: the weight ratio of the rare earth synergistic flame retardant, polypropylene, halogen-free flame retardant and antioxidant is 2:79.9:18:0.1.

[0026] Beneficial effects of the present invention:

[0027] 1. The rare earth flame retardant synergist of the present invention can be applied to multiple fields such as agricultural films, building materials and automobile parts, and also has the potential to be applied to other types of polymer materials to improve the flame retardant properties of polymer products.

[0028] 2. The present invention has excellent flame retardant synergistic performance. When combined with phosphorus-nitrogen flame retardants, it can effectively improve the flame retardant efficiency of phosphorus-nitrogen flame retardants and reduce their addition amount.

[0029] 3. The synthesis steps of the present invention are few and simple and easy to operate; the energy consumption is low and no high temperature and high pressure are required; the reaction time is short and the reaction yield is high; no organic solvent is used in the reaction process, and the preparation method is non-toxic, harmless, and green and environmentally friendly.

[0030] 4. After the present invention is applied to polymer materials, the total amount of flame retardant added can be reduced, so that the original mechanical properties of the material can be maintained, and it can help achieve a comprehensive balance between flame retardant properties and mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more completely understand the present invention, the following description is now provided in conjunction with the accompanying drawings:

[0032] Figure 1 This is the infrared test spectrum of the raw materials (phytic acid and piperazine), the intermediate product PAPI and the synergist PAPI-Ce in the preparation process of Example 1 of the present invention.

[0033] Figure 2 This is a scanning electron microscope photograph of the rare earth flame retardant synergist PAPI-Ce prepared in Example 1 of the present invention.

[0034] Figure 3 This is an X-ray electron spectrum (XPS) graph of the rare earth flame retardant synergist PAPI-Ce prepared in Example 1 of the present invention.

[0035] Figure 4 These are photos of sample strips after vertical combustion experiments of Comparative Example 2, Comparative Example 4, Example 5, Example 6 and Example 7 of the present invention.

[0036] Figure 5 This is the XPS graph of the carbon residue after combustion of the polypropylene materials prepared in Example 6, Comparative Example 2 and Comparative Example 4 of the present invention. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] The reagents used in the following examples are all commercially available. The polypropylene raw materials used in the examples were purchased from ExxonMobil, with the brand name PP1304E5. The density of the sample was 0.9 g / cm 3 , the melt flow index is 11 g / (10min) (230°C, 2.16 kg). The flame retardant grade test in the embodiment of the present invention is carried out according to the standard UL 94, the limiting oxygen index test is carried out according to the standard GBT2406.2-2009, and the cone calorimetry test is carried out according to the standard GB / T16172-2007.

[0039] Embodiment 1:

[0040] The present invention is a method for preparing a rare earth flame retardant synergist PAPI-Ce, comprising the following steps:

[0041] S1. Ce(NO3)3·6H2O (50 mmol) was dissolved in 50 mL of deionized water at room temperature to obtain solution A, and phytic acid (50 mmol) was dispersed in 50 mL of deionized water to obtain suspension B;

[0042] S2. Add 150 mmol of the piperazine derivative to the suspension B at room temperature until the piperazine derivative is completely dissolved to obtain a solution C.

[0043] S3. At room temperature, solution A was added dropwise to solution C through a dropping funnel while continuously stirring. After the addition was completed, the mixture was allowed to mature for 0.5 h at room temperature, and then centrifuged and washed with deionized water several times to obtain a solid product.

[0044] S4. The solid product is vacuum dried at 60° C. to a constant weight to obtain a rare earth flame retardant synergist PAPI-Ce.

[0045] Embodiment 2:

[0046] The present invention is a method for preparing a rare earth flame retardant synergist PAPI-La, comprising the following steps:

[0047] S1. Dissolve La(NO3)3·6H2O (50 mmol) in 50 mL of deionized water at room temperature to obtain solution A, and disperse phytic acid (50 mmol) in 50 mL of deionized water to obtain suspension B;

[0048] S2. Add 150 mmol of a piperazine derivative to the suspension B at room temperature until the piperazine is completely dissolved to obtain a solution C.

[0049] S3. At room temperature, solution A was added dropwise to solution C through a dropping funnel while continuously stirring. After the addition was completed, the mixture was allowed to mature for 0.5 h at room temperature, and then centrifuged and washed with deionized water several times to obtain a solid product.

[0050] S4. The solid product is vacuum dried at 60° C. to a constant weight to obtain a rare earth flame retardant synergist PAPI-La.

[0051] Embodiment 3:

[0052] The present invention is a method for preparing a rare earth flame retardant synergist PAPI-Y, comprising the following steps:

[0053] S1. Dissolve Y(NO3)3·6H2O (50 mmol) in 50 mL of deionized water at room temperature to obtain solution A, and disperse phytic acid (50 mmol) in 50 mL of deionized water to obtain suspension B;

[0054] S2. Add 150 mmol of the piperazine derivative to the suspension B at room temperature until the piperazine derivative is completely dissolved to obtain a solution C.

[0055] S3. At room temperature, solution A was added dropwise to solution C through a dropping funnel while continuously stirring. After the addition was completed, the mixture was allowed to mature for 0.5 h at room temperature, and then centrifuged and washed with deionized water several times to obtain a solid product.

[0056] S4. The solid product is vacuum dried at 60° C. to a constant weight to obtain a rare earth flame retardant synergist PAPI-Y.

[0057] Embodiment 4:

[0058] The present invention is a method for preparing a rare earth flame retardant synergist PAPI-Nd, comprising the following steps:

[0059] S1. Dissolve Nd(NO3)3·6H2O (50 mmol) in 50 mL of deionized water at room temperature to obtain solution A, and disperse phytic acid (50 mmol) in 50 mL of deionized water to obtain suspension B;

[0060] S2. Add 150 mmol of the piperazine derivative to the suspension B at room temperature until the piperazine derivative is completely dissolved to obtain a solution C.

[0061] S3. At room temperature, solution A was added dropwise to solution C through a dropping funnel while continuously stirring. After the addition was completed, the mixture was allowed to mature for 0.5 h at room temperature, and then centrifuged and washed with deionized water several times to obtain a solid product.

[0062] S4. The solid product is vacuum dried at 60° C. to a constant weight to obtain a rare earth flame retardant synergist PAPI-Nd.

[0063] Embodiment 5:

[0064] The PAPI-Ce prepared in Example 1 is applied to flame-retardant polypropylene, specifically comprising the following components in parts by weight: 79.9 parts of polypropylene, 1 part of rare earth flame retardant synergist PAPI-Ce, 14.3 parts of ammonium polyphosphate, 4.7 parts of pentaerythritol and 0.1 part of antioxidant 1010.

[0065] The raw materials were weighed according to the above mass ratio, added into an internal mixer for melt blending, with a melting temperature of 190° C., to obtain a flame retardant polypropylene material based on the rare earth flame retardant synergist PAPI-Re, and then relevant performance tests were performed.

[0066] Examples 6-10

[0067] The preparation methods of Examples 6-10 are the same as those of Example 5, and the specific formula compositions are shown in Table 1. The rare earth flame retardant synergist PAPI-La, rare earth flame retardant synergist PAPI-Y and rare earth flame retardant synergist PAPI-Nd are prepared from Examples 2, 3 and 4, respectively.

[0068] Comparative Example 1

[0069] 99.9 parts of polypropylene and 0.1 parts of antioxidant 1010 were added into an internal mixer without adding flame retardant, and melted under the same processing conditions as in Example 5 to obtain the polypropylene material.

[0070] Comparative Example 2

[0071] 79.9 parts of polypropylene, 15 parts of ammonium polyphosphate, 5 parts of pentaerythritol and 0.1 parts of antioxidant 1010 were added into an internal mixer and melt-blended under the same processing conditions as in Example 1 to obtain the polypropylene material.

[0072] Comparative Example 3

[0073] (1) Dissolve phytic acid (50 mmol) in 50 mL of deionized water to obtain solution A;

[0074] (2) adding 50 mmol of piperazine to solution A until the piperazine is completely dissolved to obtain solution B;

[0075] (3) Solution B was placed at room temperature for 0.5 h, and then dried at 60° C. to remove the solvent water, thereby obtaining a mixture of phytic acid and piperazine, PAPI.

[0076] Comparative Example 4

[0077] 79.9 parts of polypropylene, 2 parts of PAPI, 13.5 parts of ammonium polyphosphate, 4.5 parts of pentaerythritol and 0.1 parts of antioxidant 1010 were added into an internal mixer and melted under the same processing conditions as in Example 1 to obtain the polypropylene material.

[0078] The relevant material ratios, vertical combustion test results and mechanical property test results are shown in Table 1, where IFR is a composition of halogen-free flame retardant ammonium polyphosphate and pentaerythritol (mass ratio 3:1).

[0079] Table 1

[0080]

[0081] Table 2 Cone calorimetry test and thermogravimetric test results

[0082]

[0083] from Figure 1 From the infrared spectrum, we can see that 3206 cm -1 The bending vibration peak originally belonging to -NH on piperazine disappeared in the PAPI and PAPI-Ce spectra, while the peak at 1480 cm -1 A new peak appears at -NH2 + , indicating that the -NH on piperazine and the P-OH on the phytic acid molecule formed an -NH 2+ -OP structure. Figure 3 From the XPS spectrum, it can be seen that the valence state of Ce ions in the synergist PAPI-Ce is trivalent, and the valence state of rare earth metal ions in the raw materials has not changed after the reaction.

[0084] From Examples 1-4, it can be seen that the preparation process of the rare earth flame retardant synergist prepared by the present invention is simple, can be carried out at room temperature and pressure, and no organic solvent is used, which is environmentally friendly. From the data of Example 6 and Comparative Examples 1 / 2 / 4 in Table 1, it can be seen that the rare earth flame retardant complex and the halogen-free flame retardant have good synergistic effects and can greatly improve the flame retardant efficiency. Therefore, only a small addition ratio (2 wt%) is required to achieve the V0 flame retardant level. In addition, polypropylene will quickly self-extinguish when burning, and there will be no melt dripping phenomenon ( Figure 4). It can also be seen from the test results in Table 2 that the heat release rate of the polypropylene sample to which the synergist of the present invention is added is greatly reduced, and the ignition time is increased, indicating that the material is more flame resistant. In addition, after the synergist is added, more carbon residue remains after the thermogravimetric test, indicating that the residual carbon layer is more stable. The rare earth flame retardant synergist of the present invention can play a flame retardant role in both the gas phase and the solid phase. In the solid phase of the material matrix, the rare earth metal ions generated by the decomposition of PAPI-Re at high temperature have the ability to catalyze esterification and ester exchange reactions, effectively improving the crosslinking degree of the carbon layer. From the XPS spectrum ( Figure 5 ) It can be seen that the carbon layer remaining after the combustion of polypropylene with PAPI-Ce added has the highest content of CC bonds and PO bonds, and the lowest content of C=O bonds and P=O content, which proves that the carbon layer formed by polypropylene containing PAPI-Ce is least oxidized, that is, the carbon layer is more stable. The phosphate obtained by the decomposition of the halogen-free flame retardant will further react with the carbonate through an ester exchange reaction under the catalysis of rare earth ions, thereby forming a more compact three-dimensional network carbon layer structure, blocking the transfer of heat and oxygen to the underlying polypropylene matrix, and blocking the flammable volatile gas from entering the gas phase. In the gas phase, the gas produced by the decomposition of the intumescent flame retardant dilutes the oxygen and flammable gas. The phytic acid component in PAPI-Re will also release phosphorus-containing free radicals during the thermal decomposition process, diffuse into the gas phase, and interrupt and inhibit combustion by quenching the highly active free radicals generated by the breakage of the polymer chain. The piperazine derivative component will also produce non-flammable nitrogen-containing gas, thereby slowing down the degradation process of polypropylene. Therefore, under the dual effects of condensed phase and gas phase flame retardancy, continuous and dense highly graphitized carbon residue is produced, which is conducive to reducing the transfer of heat and oxygen, and ultimately slowing down or even preventing the combustion process. In the comparative example, due to the absence of rare earth metal ions, the carbon layer is produced in small amounts, the degree of crosslinking is low, and the stability is poor, and more flame retardant addition (currently common flame retardant additions often reach 30 wt%) is required to improve the flame retardant performance. In addition, after adding the rare earth synergist described in the present invention, the total amount of flame retardant added is reduced, so that the decline in the mechanical properties of the polypropylene material after blending is reduced, and the performance of the material in all aspects is more balanced.

[0085] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for preparing a rare earth flame retardant synergist, characterized in that: The steps include: S1. At room temperature, Re(NO)3·6H2O was dissolved in deionized water to form solution A; S2. At room temperature, phytic acid PA is added to deionized water to form solution B, and a piperazine derivative is added to solution B until the piperazine derivative is completely dissolved to obtain solution C; S3. At room temperature, solution A was added dropwise to solution C while stirring continuously. After the addition was completed, the mixture was allowed to mature for 0.5 h at room temperature, centrifuged, the precipitate was collected, and washed repeatedly until it was neutral to obtain a solid product. S4, vacuum drying the solid product at 60° C. to a constant weight, thereby obtaining the rare earth flame retardant synergist; A rare earth flame retardant synergist, the structural formula of which is: Among them, PA is phytic acid; Piperazine derivatives are PI-NH, with the structure: Or piperazine derivative is PI-NH2, the structure is: Among them, R 1-6 are each independently selected from alkyl; Re is one or more elements selected from Ce, La, Y, Nd, Sm, Eu, Gd, Dy and Tb.

2. The method for preparing a rare earth flame retardant synergist according to claim 1, characterized in that: In the solution A, the ratio of Re(NO3)3·6H2O to deionized water is 10-50mmol:10-50mL; in the solution C, the ratio of the piperazine derivative to deionized water is 10-200mmol:10-50mL.

3. The method for preparing a rare earth flame retardant synergist according to claim 2, characterized in that: The molar ratio of the phytic acid, Re(NO3)3·6H2O and the piperazine derivative is 1:1:1-3.

4. An application of a rare earth flame retardant synergist, characterized in that: The rare earth flame retardant synergist obtained by the preparation method according to claim 1 is applied to polypropylene materials for agricultural films, building materials and automotive parts to obtain flame retardant polypropylene materials.

5. The use of a rare earth flame retardant synergist according to claim 4, characterized in that: The flame retardant polypropylene material includes the following raw materials: rare earth synergistic flame retardant, polypropylene, halogen-free flame retardant and antioxidant.

6. The use of a rare earth flame retardant synergist according to claim 5, characterized in that: The halogen-free flame retardant is selected from at least one of ammonium polyphosphate, ammonium polyphosphate / pentaerythritol composition, melamine polyphosphate, melamine cyanurate, piperazine pyrophosphate, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

7. The use of a rare earth flame retardant synergist according to claim 6, characterized in that: The antioxidant is selected from at least one of the antioxidant 1010 and the antioxidant 168 .

8. The use of a rare earth flame retardant synergist according to claim 7, characterized in that: The weight ratio of the rare earth synergistic flame retardant, polypropylene, halogen-free flame retardant and antioxidant is 2:79.9:18:0.1.

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