Phosphorus-containing flame retardant with high thermal stability, preparation method of phosphorus-containing flame retardant and application of phosphorus-containing flame retardant in synthesis of flame-retardant polycarbonate

Abstract

The invention belongs to the technical field of functional materials. The invention provides a preparation method of a phosphorus-containing flame retardant with high thermal stability, which comprises the following steps: respectively dissolving a transition metal salt and a phosphorus-containing substance in a solvent, then mixing and reacting, setting the reaction temperature to be 150-180 DEG C and the reaction time to be 4-8 hours, collecting a solid product, cleaning and drying to prepare the phosphorus-containing flame retardant with high thermal stability. The invention also provides a phosphorus-containing flame retardant with high thermal stability. The invention also provides application of the phosphorus-containing flame retardant with high thermal stability in synthesis of flame-retardant polycarbonate. The invention also provides flame-retardant polycarbonate and a synthesis method thereof. The flame-retardant polycarbonate prepared by the invention has excellent flame retardance, and the flame retardant and the polycarbonate are rich in benzene ring structures and have good compatibility, so that the synthesized flame-retardant polycarbonate material has good toughness and mechanical strength, and compared with phosphate flame retardants, the flame-retardant polycarbonate material has the characteristics of high flame-retardant efficiency, high thermal stability and difficulty in hydrolysis.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional materials, and particularly relates to a phosphorus-containing high heat stability flame retardant, a preparation method thereof, and an application thereof in the synthesis of flame retardant polycarbonate. Background Art

[0002] Polycarbonate is one of the five major engineering plastics. Due to its outstanding advantages such as good mechanical properties, thermal stability, transparency, and dimensional stability, it has been widely used in the fields of electricity, construction, automotive, aviation, etc. In terms of flammability, polycarbonate has a UL-94 V-2 rating, and due to its inherent carbonization ability, the limiting oxygen index (LOI) is 23.0 - 25.0%. However, polycarbonate burns rapidly and has severe melt dripping, which can cause the spread of fire and release a large amount of toxic gases and harmful smoke. With the continuous progress of technology, people require polycarbonate to have excellent comprehensive properties to meet the market demand, especially the flame retardant performance.

[0003] Currently, flame retardants for polycarbonate are divided into halogen-containing flame retardants and halogen-free flame retardants. Halogen-based flame retardants have a good flame retardant effect on polycarbonate. However, a large amount of smoke and toxic gases generated during combustion are extremely harmful to human health and the environment. For example, fluorosulfonate flame retardants have been listed in the list of persistent organic pollutants prohibited by the Stockholm Convention. Therefore, the research on polycarbonate flame retardants mainly focuses on halogen-free flame retardants. Commonly used halogen-free flame retardants are generally sulfonates, phosphates, and silicon-based flame retardants. Among various halogen-free flame retardants, organosilicon-based flame retardants show excellent performance in improving the flame retardant performance, mechanical properties, and maintaining the transparency of materials of PC, but their synthesis process is relatively complex, while inorganic silicon-based flame retardants have a greater impact on the toughness of PC.

[0004] Phosphate flame retardants have the advantages of low toxicity, low smoke, easy processing, etc., and are currently widely used as PC flame retardants. However, there are still many problems with phosphate flame retardants in flame-retarding PC, such as the low decomposition temperature and poor thermal stability of phosphate oligomers, which are easily decomposed and volatilized at the processing temperature of PC (230 °C); some phosphates (such as m-phenylene tetraphenyl bisphosphate RDP) are in a liquid form at room temperature, resulting in adhesion to the feeding port during the feeding process, and plasticization occurs when added to PC, resulting in a greater impact on the mechanical properties of PC; aromatic phosphates (such as bisphenol A-bis(diphenyl phosphate) oligomer BDP) have good compatibility with PC, but commercially available aromatic phosphates usually have a low phosphorus content and low flame retardancy efficiency. The addition amount of BDP often needs to exceed 10.0 wt% to make PC reach the V-0 flame retardancy grade; phosphates are easily hydrolyzed during use, and the flame retardant durability of the material decreases in a humid and hot environment. CN 110003524 A discloses a halogen-free flame retardant, its synthesis method, and its application method in polycarbonate flame-retardant materials. This method synthesizes a halogen-free flame retardant DOPMI from DOPO and N-PMI, but this flame retardant has the problem of low flame retardancy efficiency. When 9.0 wt% of DOPMI is added alone, the vertical burning performance of the polycarbonate composite material only reaches UL-94 V-1 level and does not reach the UL-94 V-0 grade. According to the above content, the present invention aims to develop a phosphorus-containing flame retardant with high thermal stability and high flame retardancy efficiency for preparing flame-retardant polycarbonate composites. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a phosphorus-containing flame retardant with high thermal stability, its preparation method, and its application in synthesizing flame-retardant polycarbonate. The present invention effectively improves the flame retardancy of polycarbonate at a lower addition amount through two flame retardant mechanisms of gas phase and condensed phase.

[0006] To solve the above problems, the present invention provides the following technical solutions: A preparation method of a phosphorus-containing flame retardant with high thermal stability, comprising the following steps: dissolving a transition metal salt and a phosphorus-containing substance in a solvent respectively, then mixing and reacting, setting the reaction temperature at 150 °C to 180 °C, and the reaction time at 4 to 8 h, collecting the solid product, washing, and drying to prepare a phosphorus-containing flame retardant with high thermal stability.

[0007] In the preparation method of a phosphorus-containing flame retardant with high thermal stability as described above, the transition metal element of the transition metal salt is any one or more of Fe, Co, Cu, Ni, Al, Mn, Cr, Mg, Ca, Zn, or La; the phosphorus-containing substance is DOPO. In the present invention, DOPO refers to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0008] A preparation method of a phosphorus-containing flame retardant with high thermal stability as described above, wherein the transition metal salt is any one or more of iron acetylacetonate, cobalt acetylacetonate, copper acetylacetonate, nickel acetylacetonate, aluminum acetylacetonate, manganese acetylacetonate, chromium acetylacetonate, magnesium acetylacetonate, calcium acetylacetonate, zinc acetylacetonate or lanthanum acetylacetonate. The organometallic salt is soluble in organic solvents and can undergo a homogeneous reaction with DOPO in organic solvents. The organometallic salt contains a coordination bond, has higher thermal stability than traditional organophosphorus flame retardants, and the transition metal element itself has a catalytic carbonization effect and has a synergistic flame retardant effect with phosphorus elements, which is suitable for the purpose of preparing a high flame retardancy and high thermal stability flame retardant of the present invention.

[0009] A preparation method of a phosphorus-containing flame retardant with high thermal stability as described above, wherein the molar ratio of the transition metal salt to the phosphorus-containing substance is (1:2) to (1:5). Preferably, the molar ratio of the transition metal salt to the phosphorus-containing substance is 1:2 or 1:3. When the transition metal ion is a divalent ion, the molar ratio of the transition metal salt to the phosphorus-containing substance is 1:2. When the transition metal ion is a trivalent ion, the molar ratio of the transition metal salt to the phosphorus-containing substance is 1:3. The flame retardant with this reaction ratio has a more stable chemical structure, high thermal stability, appropriate phosphorus and transition metal elements in the structure, and high synergistic flame retardant efficiency.

[0010] A preparation method of a phosphorus-containing flame retardant with high thermal stability as described above, wherein the solvent is any one of dimethyl sulfoxide, N,N-dimethylformamide, N-methylpyrrolidone, and dimethylacetamide. Preferably, the solvent is dimethyl sulfoxide. Dimethyl sulfoxide has good solubility for reactants and has a relatively high boiling point and is stable under high reaction temperature conditions.

[0011] A preparation method of a phosphorus-containing flame retardant with high thermal stability as described above, wherein the synthesis route of the preparation method is shown in Formula (Ⅰ) or Formula (Ⅱ):

[0012] Formula (Ⅰ) In the Formula (Ⅰ), M is any one of Co, Cu, Ni, Mn, Mg, Ca or Zn;

[0013] Formula (Ⅱ) In the Formula (Ⅱ), M is any one of Fe, Al, Cr or La.

[0014] Based on the same inventive concept, the present invention also provides a phosphorus-containing flame retardant with high thermal stability, which is prepared by the preparation method as described above.

[0015] Based on the same inventive concept, the present invention also provides a phosphorus-containing highly thermostable flame retardant prepared by the above-described preparation method, or the application of the phosphorus-containing highly thermostable flame retardant as described above in the synthesis of flame-retardant polycarbonate.

[0016] Based on the same inventive concept, the present invention also provides a method for synthesizing flame-retardant polycarbonate, comprising the following steps: Step 1, after preparing the phosphorus-containing highly thermostable flame retardant by the above-described preparation method, dry it for standby; Step 2, dry the pure polycarbonate masterbatch at 80 °C to 100 °C for standby to remove the possible water on the surface of the polycarbonate and prevent the appearance of dense bubbles during melt blending; Step 3, melt blend the polycarbonate dried in Step 2 with the flame retardant prepared in Step 1. The mass ratio of the polycarbonate to the flame retardant is 100:(1 - 5). The temperature of the melt blending is 200 °C to 250 °C, the rotation speed is 50 - 100 r / min, and the blending time is 10 - 15 min. After cooling, the obtained product is the flame-retardant polycarbonate material. Preferably, the mass ratio of the polycarbonate to the flame retardant is 100:3. At this ratio, the flame retardancy of the polycarbonate can reach the UL-94 vertical burning V-0 grade, and the mechanical properties of the polycarbonate itself can be maintained without reduction. Preferably, the temperature of the melt blending is 230 °C, the rotation speed is 60 r / min, and the blending time is 15 min. These melt blending conditions can ensure the uniform dispersion of the flame retardant in the polycarbonate matrix.

[0017] The principle of the present invention is as follows: The synthesis raw materials of the highly thermostable phosphorus-containing flame retardant prepared by the present invention are DOPO and acetylacetone compounds containing transition metal elements. By using the addition reaction of DOPO and acetylacetone transition metal salts, a flame retardant containing phosphorus elements and transition metal elements is synthesized. This flame retardant is rich in benzene ring structures and coordination bonds. On the one hand, the flame retardant has good thermal stability (the initial thermal decomposition temperature of the flame retardant > 520 °C). On the other hand, it has good compatibility with polycarbonate, which is also rich in benzene ring structures, based on π-π stacking interactions, and enhances its flame retardancy without reducing the mechanical properties of the polycarbonate. The DOPO structure has a gas-phase flame retardant effect, specifically manifested as the decomposition at high temperature to generate phosphorus-containing free radicals to interrupt the chain reaction of the combustion process to achieve the flame retardant purpose, while the transition metal elements can play a role in catalyzing the cross-linking and carbonization of polycarbonate in the condensed phase. The dense carbon layer can isolate oxygen and heat and prevent the decomposition of combustible substances. Based on the synergistic effect of condensed-phase and gas-phase flame retardancy, this flame retardant can effectively improve the flame retardancy and thermal stability of polycarbonate at a lower addition amount.

[0018] Based on the same inventive concept, the present invention also provides a flame-retardant polycarbonate synthesized by the above-described synthesis method.

[0019] Compared with the existing technology, the effects and advantages of the present invention are as follows: 1. A phosphorus-containing high heat stability flame retardant prepared by the present invention has the advantages of low toxicity, low smoke and easy processing. The initial pyrolysis temperature of the flame retardant provided by the present invention is between 520 and 532 °C, the maximum pyrolysis temperature of the flame retardant is between 538 and 550 °C, and the char residue rate of the flame retardant at 800 °C is between 61% and 63%, having high heat stability and excellent char-forming performance.

[0020] 2. A flame-retardant polycarbonate synthesized by the present invention. Experiments have proved that the peak heat release rate of the flame-retardant polycarbonate added with the synthesized flame retardant is between 506 and 588 kW / m 2 , the total heat release is between 35 and 62 MJ / m 2 , the limiting oxygen index is between 27.9% and 29.1%, and the vertical burning UL-94 test all reaches the V-0 level. The initial pyrolysis temperature is between 423 and 453 °C, the maximum pyrolysis temperature is between 460 and 480 °C, and the char residue rate at 800 °C is between 19.2% and 22.1%, having good flame retardant performance and less total heat release during the combustion process. Taking the comparison between Example 1 and Comparative Example 1 of the present invention as an example, the peak heat release rate of the polycarbonate material added with the flame retardant prepared by the present invention decreased by 42.4%, the total heat release decreased by 44.4%, the limiting oxygen index increased to 29.1%, and the vertical burning UL-94 test reached the V-0 level.

[0021] 3. A method for synthesizing a flame-retardant polycarbonate provided by the present invention. Since both the flame retardant and the polycarbonate are rich in benzene ring structures and have good compatibility, the synthesized flame-retardant polycarbonate material has good toughness and mechanical strength.

[0022] 4. A method for preparing a phosphorus-containing high heat stability flame retardant provided by the present invention has a simple process flow, and the flame retardant has the characteristics of high flame retardancy efficiency, high heat stability and not easy to hydrolyze. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a comparison chart of UL-94 vertical burning tests for Example 1, Example 2 and Comparative Example 1 of the present invention.

[0024] Figure 2 It is a comparison chart of heat release rates for Example 1, Example 2 and Comparative Example 1 of the present invention.

[0025] Figure 3 It is a comparison chart of total heat release amounts for Example 1, Example 2 and Comparative Example 1 of the present invention.

[0026] Figure 4FTIR spectra of the DOPO@Fe flame retardant of Example 1, the DOPO@Co flame retardant of Example 2, and the DOPO flame retardant of Comparative Example 2 of the present invention.

[0027] Figure 5 SEM micrograph of the DOPO@Fe flame retardant of Example 1 of the present invention.

[0028] Figure 6 SEM micrograph of the DOPO@Co flame retardant of Example 2 of the present invention. Detailed implementation manners

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the content in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of 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.

[0030] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific implementation manners and are not used to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0031] The experimental methods used in the following embodiments are all conventional methods unless otherwise specified.

[0032] The materials, reagents, etc. used in the following embodiments can be obtained from commercial sources unless otherwise specified.

[0033] In the present invention, the synthesis routes of a preparation method of a phosphorus-containing high heat stability flame retardant provided in the following embodiments are shown in Formula (I) or Formula (II):

[0034] Formula (I) In the said Formula (I), M is any one of Co, Cu, Ni, Mn, Mg, Ca or Zn; M is a divalent metal ion.

[0035]

[0036] Formula (II) In the said Formula (II), M is any one of Fe, Al, Cr or La; M is a trivalent metal ion.

[0037] The polycarbonate masterbatch, model K-1300, is purchased from Teijin Limited (Japan).

[0038] Example 1: This example provides a flame-retardant polycarbonate, and its synthesis method includes the following steps: Step 1: Dissolve 10 mmol of iron acetylacetonate in 100 mL of dimethyl sulfoxide, and dissolve 30 mmol of DOPO in 150 mL of dimethyl sulfoxide. Add the two to a 500 mL flask and place it in an oil bath for mixing reaction. Set the reaction temperature to 160 °C, carry out condensation reflux, turn on the magnetic stirrer with a stirring speed of 300 r / min, and react for 6 h. After the reaction, a solid product will precipitate. Collect the solid product, wash it with ethanol, and dry it at 100 °C for standby to obtain a phosphorus-containing flame retardant with high thermal stability.

[0039] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for standby.

[0040] Step 3: Add 50 g of the polycarbonate dried in Step 2 and 1.5 g of the flame retardant prepared in Step 1 to a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and cool to room temperature. The obtained product is the flame-retardant polycarbonate material.

[0041] The test results of the flame-retardant polycarbonate material in this example are shown in Table 1, and the thermal stability test results of the flame retardant in Step 1 are shown in Table 2.

[0042] Example 2: This example provides a flame-retardant polycarbonate, and its synthesis method includes the following steps: Step 1: Dissolve 15 mmol of cobalt acetylacetonate in 100 mL of dimethyl sulfoxide, and dissolve 30 mmol of DOPO in 150 mL of dimethyl sulfoxide. Add the two to a 500 mL flask and place it in an oil bath for mixing reaction. Set the reaction temperature to 160 °C, carry out condensation reflux, turn on the magnetic stirrer with a stirring speed of 300 r / min, and react for 6 h. After the reaction, a solid product will precipitate. Collect the solid product, wash it with ethanol, and dry it at 100 °C for standby to obtain a phosphorus-containing flame retardant with high thermal stability.

[0043] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for standby.

[0044] Step 3: Add 50 g of the polycarbonate dried in Step 2 and 1.5 g of the flame retardant prepared in Step 1 to a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and cool to room temperature. The obtained product is the flame-retardant polycarbonate material.

[0045] The test results of the flame-retardant polycarbonate material in this example are shown in Table 1, and the thermal stability test results of the flame retardant in Step 1 are shown in Table 2.

[0046] Example 3: This example provides a flame-retardant polycarbonate, and its synthesis method includes the following steps: Step 1: Dissolve 15 mmol of copper acetylacetonate in 100 mL of dimethyl sulfoxide, and dissolve 30 mmol of DOPO in 150 mL of dimethyl sulfoxide. Add the two into a 500 mL flask and place it in an oil bath for mixing reaction. Set the reaction temperature to 160 °C, carry out condensation reflux, turn on the magnetic stirrer with a stirring speed of 300 r / min, and react for 6 h. After the reaction, solid products will precipitate. Collect the solid products, wash them with ethanol, and dry them at 100 °C for standby to obtain a phosphorus-containing flame retardant with high thermal stability.

[0047] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for standby.

[0048] Step 3: Add 50 g of the polycarbonate dried in Step 2 and 1.5 g of the flame retardant prepared in Step 1 into a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and cool it to room temperature. The obtained product is the flame-retardant polycarbonate material.

[0049] The test results of the flame-retardant polycarbonate material in this example are shown in Table 1, and the thermal stability test results of the flame retardant in Step 1 are shown in Table 2.

[0050] Example 4: This example provides a flame-retardant polycarbonate, and its synthesis method includes the following steps: Step 1: Dissolve 15 mmol of nickel acetylacetonate in 100 mL of dimethyl sulfoxide, and dissolve 30 mmol of DOPO in 150 mL of dimethyl sulfoxide. Add the two into a 500 mL flask and place it in an oil bath for mixing reaction. Set the reaction temperature to 160 °C, carry out condensation reflux, turn on the magnetic stirrer with a stirring speed of 300 r / min, and react for 6 h. After the reaction, solid products will precipitate. Collect the solid products, wash them with ethanol, and dry them at 100 °C for standby to obtain a phosphorus-containing flame retardant with high thermal stability.

[0051] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for standby.

[0052] Step 3: Add 50 g of the polycarbonate dried in Step 2 and 1.5 g of the flame retardant prepared in Step 1 into a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and cool it to room temperature. The obtained product is the flame-retardant polycarbonate material.

[0053] The test results of the flame-retardant polycarbonate material in this example are shown in Table 1, and the thermal stability test results of the flame retardant in Step 1 are shown in Table 2.

[0054] Example 5: This example provides a flame-retardant polycarbonate, and its synthesis method includes the following steps: Step 1: Dissolve 10 mmol of aluminum acetylacetonate in 100 mL of dimethyl sulfoxide, and dissolve 30 mmol of DOPO in 150 mL of dimethyl sulfoxide. Add the two into a 500 mL flask and place it in an oil bath for mixing reaction. The reaction temperature is set at 160 °C, with condensation reflux, and turn on the magnetic stirrer with a stirring speed of 300 r / min for 6 h. After the reaction is completed, a solid product will precipitate. Collect the solid product, wash it with ethanol, and dry it at 100 °C for standby to obtain a phosphorus-containing flame retardant with high thermal stability.

[0055] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for standby.

[0056] Step 3: Add 50 g of the polycarbonate dried in Step 2 and 1.5 g of the flame retardant prepared in Step 1 into a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and cool it to room temperature. The obtained product is the flame-retardant polycarbonate material.

[0057] The test results of the flame-retardant polycarbonate material in this example are shown in Table 1, and the thermal stability test results of the flame retardant in Step 1 are shown in Table 2.

[0058] Example 6: This example provides a flame-retardant polycarbonate, and its synthesis method includes the following steps: Step 1: Dissolve 15 mmol of manganese acetylacetonate in 100 mL of dimethyl sulfoxide, and dissolve 30 mmol of DOPO in 150 mL of dimethyl sulfoxide. Add the two into a 500 mL flask and place it in an oil bath for mixing reaction. The reaction temperature is set at 160 °C, with condensation reflux, and turn on the magnetic stirrer with a stirring speed of 300 r / min for 6 h. After the reaction is completed, a solid product will precipitate. Collect the solid product, wash it with ethanol, and dry it at 100 °C for standby to obtain a phosphorus-containing flame retardant with high thermal stability.

[0059] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for standby.

[0060] Step 3: Add 50 g of the polycarbonate dried in Step 2 and 1.5 g of the flame retardant prepared in Step 1 into a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and cool it to room temperature. The obtained product is the flame-retardant polycarbonate material.

[0061] The test results of the flame-retardant polycarbonate material in this example are shown in Table 1, and the thermal stability test results of the flame retardant in Step 1 are shown in Table 2.

[0062] Example 7: This example provides a flame-retardant polycarbonate, and its synthesis method includes the following steps: Step 1: Dissolve 10 mmol of chromium acetylacetonate in 100 mL of dimethyl sulfoxide, and dissolve 30 mmol of DOPO in 150 mL of dimethyl sulfoxide. Add the two into a 500 mL flask and place it in an oil bath for mixing reaction. The reaction temperature is set at 160 °C, with condensation reflux, and turn on the magnetic stirrer with a stirring speed of 300 r / min. The reaction time is 6 h. After the reaction is completed, a solid product will precipitate. Collect the solid product, wash it with ethanol, and dry it at 100 °C for standby, thus obtaining a phosphorus-containing flame retardant with high thermal stability.

[0063] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for standby.

[0064] Step 3: Add 50 g of the polycarbonate dried in Step 2 and 1.5 g of the flame retardant prepared in Step 1 into a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and cool it to room temperature. The obtained product is the flame-retardant polycarbonate material.

[0065] The test results of the flame-retardant polycarbonate material in this example are shown in Table 1, and the thermal stability test results of the flame retardant in Step 1 are shown in Table 2.

[0066] Example 8: This example provides a flame-retardant polycarbonate, and its synthesis method includes the following steps: Step 1: Dissolve 15 mmol of magnesium acetylacetonate in 100 mL of dimethyl sulfoxide, and dissolve 30 mmol of DOPO in 150 mL of dimethyl sulfoxide. Add the two into a 500 mL flask and place it in an oil bath for mixing reaction. The reaction temperature is set at 160 °C, with condensation reflux, and turn on the magnetic stirrer with a stirring speed of 300 r / min. The reaction time is 6 h. After the reaction is completed, a solid product will precipitate. Collect the solid product, wash it with ethanol, and dry it at 100 °C for standby, thus obtaining a phosphorus-containing flame retardant with high thermal stability.

[0067] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for standby.

[0068] Step 3: Add 50 g of the polycarbonate dried in Step 2 and 1.5 g of the flame retardant prepared in Step 1 into a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and cool it to room temperature. The obtained product is the flame-retardant polycarbonate material.

[0069] The test results of the flame-retardant polycarbonate material in this example are shown in Table 1, and the thermal stability test results of the flame retardant in Step 1 are shown in Table 2.

[0070] Example 9: This example provides a flame-retardant polycarbonate, and its synthesis method includes the following steps: Step 1: Dissolve 15 mmol of calcium acetylacetonate in 100 mL of dimethyl sulfoxide, and dissolve 30 mmol of DOPO in 150 mL of dimethyl sulfoxide. Add the two into a 500 mL flask and place it in an oil bath for mixing reaction. Set the reaction temperature to 160 °C, carry out condensation reflux, turn on the magnetic stirrer with a stirring speed of 300 r / min, and react for 6 h. After the reaction, a solid product will precipitate. Collect the solid product, wash it with ethanol, and dry it at 100 °C for standby to obtain a phosphorus-containing flame retardant with high thermal stability.

[0071] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for standby.

[0072] Step 3: Add 50 g of the polycarbonate dried in Step 2 and 1.5 g of the flame retardant prepared in Step 1 into a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and cool it to room temperature. The obtained product is the flame-retardant polycarbonate material.

[0073] The test results of the flame-retardant polycarbonate material in this example are shown in Table 1, and the thermal stability test results of the flame retardant in Step 1 are shown in Table 2.

[0074] Example 10: This example provides a flame-retardant polycarbonate, and its synthesis method includes the following steps: Step 1: Dissolve 15 mmol of zinc acetylacetonate in 100 mL of dimethyl sulfoxide, and dissolve 30 mmol of DOPO in 150 mL of dimethyl sulfoxide. Add the two into a 500 mL flask and place it in an oil bath for mixing reaction. Set the reaction temperature to 160 °C, carry out condensation reflux, turn on the magnetic stirrer with a stirring speed of 300 r / min, and react for 6 h. After the reaction, a solid product will precipitate. Collect the solid product, wash it with ethanol, and dry it at 100 °C for standby to obtain a phosphorus-containing flame retardant with high thermal stability.

[0075] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for standby.

[0076] Step 3: Add 50 g of the polycarbonate dried in Step 2 and 1.5 g of the flame retardant prepared in Step 1 into a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and cool it to room temperature. The obtained product is the flame-retardant polycarbonate material.

[0077] The test results of the flame-retardant polycarbonate material in this example are shown in Table 1, and the thermal stability test results of the flame retardant in Step 1 are shown in Table 2.

[0078] Example 11: This example provides a flame-retardant polycarbonate, and its synthesis method includes the following steps: Step 1: Dissolve 10 mmol of lanthanum acetylacetonate in 100 mL of dimethyl sulfoxide, and dissolve 30 mmol of DOPO in 150 mL of dimethyl sulfoxide. Add the two to a 500 mL flask and place it in an oil bath for mixing reaction. Set the reaction temperature to 160 °C, carry out condensation reflux, turn on the magnetic stirrer with a stirring speed of 300 r / min, and react for 6 h. After the reaction ends, a solid product will precipitate. Collect the solid product, wash it with ethanol, and dry it at 100 °C for standby to obtain a phosphorus-containing flame retardant with high thermal stability.

[0079] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for standby.

[0080] Step 3: Add 50 g of the polycarbonate dried in Step 2 and 1.5 g of the flame retardant prepared in Step 1 to a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and cool it to room temperature. The obtained product is the flame-retardant polycarbonate material.

[0081] The test results of the flame-retardant polycarbonate material in this example are shown in Table 1, and the thermal stability test results of the flame retardant in Step 1 are shown in Table 2.

[0082] Comparative Example 1: This comparative example provides a polycarbonate, and its synthesis method includes the following steps: Step 1: Dry the pure polycarbonate masterbatch at 100 °C for standby.

[0083] Step 2: Add 50 g of the polycarbonate dried in Step 2 to a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melting, and cool it to room temperature. The obtained product is the pure polycarbonate material.

[0084] The test results of the flame-retardant polycarbonate material in this comparative example are shown in Table 1, and the thermal stability test results of the flame retardant in Step 1 are shown in Table 2.

[0085] Comparative Example 2: This comparative example provides a polycarbonate, and its synthesis method includes the following steps: Step 1: Use DOPO as the flame retardant and prepare dry DOPO powder for standby.

[0086] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for standby.

[0087] Step 3: Add 50 g of the polycarbonate dried in Step 2 and 1.5 g of DOPO to a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and then cool to room temperature. The resulting product is the polycarbonate material.

[0088] The test results of the flame-retardant polycarbonate material of this comparative example are shown in Table 1, and the test results of the thermal stability of the flame retardant in Step 1 are shown in Table 2.

[0089] Comparative Example 3: This comparative example provides a polycarbonate, and its synthesis method includes the following steps: Step 1: Use iron acetylacetonate as the flame retardant, and prepare dry iron acetylacetonate powder for later use.

[0090] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for later use.

[0091] Step 3: Add 50 g of the polycarbonate dried in Step 2 and 1.5 g of iron acetylacetonate to a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and then cool to room temperature. The resulting product is the polycarbonate material.

[0092] The test results of the flame-retardant polycarbonate material of this comparative example are shown in Table 1, and the test results of the thermal stability of the flame retardant in Step 1 are shown in Table 2.

[0093] Comparative Example 4: This comparative example provides a polycarbonate, and its synthesis method includes the following steps: Step 1: Use cobalt acetylacetonate as the flame retardant, and prepare dry cobalt acetylacetonate powder for later use.

[0094] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for later use.

[0095] Step 3: Add 50 g of the polycarbonate dried in Step 2 and 1.5 g of cobalt acetylacetonate to a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and then cool to room temperature. The resulting product is the polycarbonate material.

[0096] The test results of the flame-retardant polycarbonate material of this comparative example are shown in Table 1, and the test results of the thermal stability of the flame retardant in Step 1 are shown in Table 2.

[0097] Comparative Example 5: This comparative example provides a polycarbonate, and its synthesis method includes the following steps: Step 1: Use copper acetylacetonate as the flame retardant, and prepare dry copper acetylacetonate powder for later use.

[0098] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for later use.

[0099] Step 3: Add 50 g of the polycarbonate dried in Step 2 and 1.5 g of copper acetylacetonate to a torque rheometer at a temperature of 230°C and a rotation speed of 60 r / min for melt blending for 15 min, and then cool at room temperature. The resulting product is the polycarbonate material.

[0100] The test results of the flame-retardant polycarbonate material of this comparative example are shown in Table 1, and the test results of the thermal stability of the flame retardant in Step 1 are shown in Table 2.

[0101] Comparative Example 6: This comparative example provides a polycarbonate, and its synthesis method includes the following steps: Step 1: Use nickel acetylacetonate as the flame retardant, and prepare dry nickel acetylacetonate powder for standby.

[0102] Step 2: Dry the pure polycarbonate masterbatch at 100°C for standby.

[0103] Step 3: Add 50 g of the polycarbonate dried in Step 2 and 1.5 g of nickel acetylacetonate to a torque rheometer at a temperature of 230°C and a rotation speed of 60 r / min for melt blending for 15 min, and then cool at room temperature. The resulting product is the polycarbonate material.

[0104] The test results of the flame-retardant polycarbonate material of this comparative example are shown in Table 1, and the test results of the thermal stability of the flame retardant in Step 1 are shown in Table 2.

[0105] Comparative Example 7: This comparative example provides a polycarbonate, and its synthesis method includes the following steps: Step 1: Use aluminum acetylacetonate as the flame retardant, and prepare dry aluminum acetylacetonate powder for standby.

[0106] Step 2: Dry the pure polycarbonate masterbatch at 100°C for standby.

[0107] Step 3: Add 50 g of the polycarbonate dried in Step 2 and 1.5 g of aluminum acetylacetonate to a torque rheometer at a temperature of 230°C and a rotation speed of 60 r / min for melt blending for 15 min, and then cool at room temperature. The resulting product is the polycarbonate material.

[0108] The test results of the flame-retardant polycarbonate material of this comparative example are shown in Table 1, and the test results of the thermal stability of the flame retardant in Step 1 are shown in Table 2.

[0109] Comparative Example 8: This comparative example provides a polycarbonate, and its synthesis method includes the following steps: Step 1: Use manganese acetylacetonate as the flame retardant, and prepare dry manganese acetylacetonate powder for standby.

[0110] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for later use.

[0111] Step 3: Add 50 g of the dried polycarbonate from Step 2 and 1.5 g of manganese acetylacetonate to a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and then cool at room temperature. The obtained product is the polycarbonate material.

[0112] The test results of the flame-retardant polycarbonate material in this comparative example are shown in Table 1, and the test results of the thermal stability of the flame retardant in Step 1 are shown in Table 2.

[0113] Comparative Example 9: This comparative example provides a polycarbonate, and its synthesis method includes the following steps: Step 1: Use chromium acetylacetonate as the flame retardant, and prepare dry chromium acetylacetonate powder for later use.

[0114] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for later use.

[0115] Step 3: Add 50 g of the dried polycarbonate from Step 2 and 1.5 g of chromium acetylacetonate to a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and then cool at room temperature. The obtained product is the polycarbonate material.

[0116] The test results of the flame-retardant polycarbonate material in this comparative example are shown in Table 1, and the test results of the thermal stability of the flame retardant in Step 1 are shown in Table 2.

[0117] Comparative Example 10: This comparative example provides a polycarbonate, and its synthesis method includes the following steps: Step 1: Use magnesium acetylacetonate as the flame retardant, and prepare dry magnesium acetylacetonate powder for later use.

[0118] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for later use.

[0119] Step 3: Add 50 g of the dried polycarbonate from Step 2 and 1.5 g of magnesium acetylacetonate to a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and then cool at room temperature. The obtained product is the polycarbonate material.

[0120] The test results of the flame-retardant polycarbonate material in this comparative example are shown in Table 1, and the test results of the thermal stability of the flame retardant in Step 1 are shown in Table 2.

[0121] Comparative Example 11: This comparative example provides a polycarbonate, and its synthesis method includes the following steps: Step 1: Take calcium acetylacetonate as a flame retardant and prepare dry calcium acetylacetonate powder for later use.

[0122] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for later use.

[0123] Step 3: Add 50 g of the dried polycarbonate from Step 2 and 1.5 g of calcium acetylacetonate to a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and then cool at room temperature. The resulting product is the polycarbonate material.

[0124] The test results of the flame-retardant polycarbonate material in this comparative example are shown in Table 1, and the test results of the thermal stability of the flame retardant in Step 1 are shown in Table 2.

[0125] Comparative Example 12: This comparative example provides a polycarbonate, and its synthesis method includes the following steps: Step 1: Take zinc acetylacetonate as a flame retardant and prepare dry zinc acetylacetonate powder for later use.

[0126] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for later use.

[0127] Step 3: Add 50 g of the dried polycarbonate from Step 2 and 1.5 g of zinc acetylacetonate to a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and then cool at room temperature. The resulting product is the polycarbonate material.

[0128] The test results of the flame-retardant polycarbonate material in this comparative example are shown in Table 1, and the test results of the thermal stability of the flame retardant in Step 1 are shown in Table 2.

[0129] Comparative Example 13: This comparative example provides a polycarbonate, and its synthesis method includes the following steps: Step 1: Take lanthanum acetylacetonate as a flame retardant and prepare dry lanthanum acetylacetonate powder for later use.

[0130] Step 2: Dry the pure polycarbonate masterbatch at 100 °C for later use.

[0131] Step 3: Add 50 g of the dried polycarbonate from Step 2 and 1.5 g of lanthanum acetylacetonate to a torque rheometer at a temperature of 230 °C and a rotation speed of 60 r / min for melt blending for 15 min, and then cool at room temperature. The resulting product is the polycarbonate material.

[0132] The test results of the flame-retardant polycarbonate material in this comparative example are shown in Table 1, and the test results of the thermal stability of the flame retardant in Step 1 are shown in Table 2.

[0133] The flame retardants prepared in Step 1 of Examples 1-11 and the flame retardants prepared or used in Step 1 of Comparative Examples 2-13 were subjected to thermal stability tests. Through thermogravimetric analysis tests, the initial thermal decomposition temperature and the maximum thermal decomposition temperature of the flame retardants were obtained to characterize their thermal stability performance, and the char residue rate at 800 °C was used to characterize their fire resistance performance. The test results are shown in Table 2.

[0134] The polycarbonate materials prepared in Examples 1-11 and Comparative Examples 1-13 were subjected to thermal stability and flame retardancy tests.

[0135] The flame retardancy of the material was macroscopically reflected through the UL-94 vertical burning test, referring to the standard GB / T2408-2008. The limiting oxygen index (LOI) was measured by an oxygen index meter, referring to the standard GB / T2406-2009. The initial thermal decomposition temperature and the maximum thermal decomposition temperature of the material were obtained through thermogravimetric analysis to characterize its thermal stability performance, and the char residue rate at 800 °C was used to characterize its fire resistance performance. The peak heat release rate and the total heat release of the material were obtained through cone calorimeter tests to quantify the flame retardancy of the material. The test results are shown in Table 1.

[0136] Initial thermal decomposition temperature: It refers to the temperature at which the mass loss of the material due to thermal decomposition reaches 5% of the overall mass.

[0137] Maximum thermal decomposition temperature: It refers to the temperature corresponding to the fastest rate of thermal decomposition of the material.

[0138] Char residue rate: It refers to the percentage of the mass of the substance remaining after the material decomposes under certain high-temperature conditions to the original mass. A high char residue rate indicates that the material has a high char-forming ability and fire resistance performance.

[0139] UL-94 vertical burning test grading: V-0 (after two 10-second burning tests on the sample, the flame extinguishes within 10 seconds and no burning substances can fall), V-1 (after two 10-second burning tests on the sample, the burning substances do not drip or the dripped substances do not ignite the cotton), V-2 (after two 10-second burning tests on the sample, the burning substances drip and ignite the cotton).

[0140] Limiting oxygen index (LOI) test: The lowest oxygen concentration required for the specimen to maintain balanced combustion in a mixed gas of oxygen and nitrogen. The higher the index, the more difficult it is to burn.

[0141] Heat release rate: It refers to the amount of heat released by the material combustion per unit time under specified experimental conditions.

[0142] [[ID=I27]]Total heat release: It refers to the total amount of heat released by the material combustion under specified experimental conditions.

[0143] Table 1 Test results of thermal stability and flame retardancy of polycarbonate materials prepared in Examples 1-11 and Comparative Examples 1-13

[0144] Table 2 Test Results of Thermal Stability of Flame Retardants for Examples 1-11 and Comparative Examples 2-13

[0145] By comparing the data of each example of the flame-retardant polycarbonate material in Table 1, the peak heat release rate of the flame-retardant polycarbonate materials in Examples 1-11 is 506-588 kW / m 2 , and the total heat release is 35-62 MJ / m 2 . The UL-94 can reach the V-0 grade, and the limiting oxygen index is 27.9-29.1%; the initial pyrolysis temperature of the flame-retardant polycarbonate material is 423-453 °C, the maximum pyrolysis temperature is 460-480 °C, and the char residue rate of the flame-retardant material at 800 °C is 19.2-22.1%. By comparing with the data of Comparative Example 1, that is, pure polycarbonate, it is found that all examples can have relatively high flame retardancy and thermal stability. Taking the comparison between Example 1 of the present invention and Comparative Example 1 as an example, the peak heat release rate of the polycarbonate material added with the flame retardant prepared in the present invention decreased by 42.4%, the total heat release decreased by 44.4%, the limiting oxygen index increased to 29.1%, and the vertical burning UL-94 test reached the V-0 level. The optimal example is Example 1, and the relatively poor one among Examples 1-11 is Example 9. The reason may be that the synergistic flame retardant effect of phosphorus and iron is better, and its calcium has a slightly worse synergistic flame retardant effect with phosphorus than other metal ions, and its ability to catalyze the carbonization of polycarbonate during combustion is relatively low.

[0146] For the data of each example of the thermal properties of each flame retardant in Table 2, the initial pyrolysis temperature, that is, the maximum pyrolysis temperature, of each flame retardant in Examples 1-11 is above 500 °C, and the char residue rate at 800 °C is greater than 60%. Among them, the DOPO@Fe flame retardant in Example 1 and the DOPO@Co flame retardant in Example 2 have relatively excellent data performance, and their maximum thermal decomposition temperatures are 547 °C and 550 °C respectively. Since Comparative Example 1 is a non-flame retardant, which is a pure polycarbonate material, it is not shown in Table 2.

[0147] Through the comprehensive comparison of the data of the flame-retardant polycarbonate material in Table 1 and the thermal property data of each flame retardant in Table 2, it is concluded that the DOPO@Fe flame retardant and DOPO@Co flame retardant prepared in the present invention have relatively better flame retardancy and thermal stability compared with other flame retardants. Therefore, these two substances should be preferably used as the flame retardant raw materials for synthesizing flame-retardant polycarbonate materials.

[0148] Figure 1 This is a comparison chart of the UL-94 vertical burning test for Example 1, Example 2 and Comparative Example 1 of the present invention. From Figure 1It can be seen that after the external ignition flame ignition test condition lasting for 10 seconds, Comparative Example 1 continued to burn and could not self-extinguish. At the same time, a melting drop phenomenon occurred and the cotton below was ignited. After the external ignition flame ignition test condition lasting for 10 seconds, the ignition source was removed in both Example 1 and Example 2, and self-extinguishing could be achieved within 4 seconds, and there was no molten dripping phenomenon.

[0149] Figure 2 This is a comparison chart of the heat release rates of Example 1, Example 2 and Comparative Example 1 of the present invention.

[0150] Figure 3 This is a comparison chart of the total heat release amounts of Example 1, Example 2 and Comparative Example 1 of the present invention.

[0151] From Figure 2 and Figure 3 it can be seen that compared with Comparative Example 1, Example 1 and Example 2 have lower heat release rates and total heat release amounts, indicating that the flame retardants in the examples of the present invention can significantly reduce the heat release of polycarbonate.

[0152] Figure 4 This is the FTIR diagram of the DOPO@Fe flame retardant in Example 1, the DOPO@Co flame retardant in Example 2 and the DOPO flame retardant in Comparative Example 2 of the present invention. From Figure 4 it can be seen that compared with DOPO, new infrared characteristic peaks appear in the DOPO@Fe flame retardant and the DOPO@Co flame retardant. The appearance of the new characteristic peaks is due to the addition reaction of iron acetylacetonate and cobalt acetylacetonate with DOPO, which are thus introduced into the chemical structures of the two flame retardants.

[0153] Figure 5 This is the SEM electron micrograph of DOPO@Fe in Example 1 of the present invention. From Figure 5 it can be seen that DOPO@Fe has a spherical microstructure with an average particle size of 240 nanometers.

[0154] Figure 6 This is the SEM electron micrograph of DOPO@Co in Example 2 of the present invention. From Figure 6 it can be seen that DOPO@Co has a two-dimensional sheet-like microstructure.

[0155] It should be noted that the specific embodiments are only relatively representative examples of the present invention. Obviously, the technical solutions of the present invention are not limited to the above embodiments and there can be many variations. Those of ordinary skill in the art who obtain without any doubt based on what is clearly disclosed in the present invention or according to the written description of the document should be considered as within the scope protected by this patent.

Claims

1. A preparation method of a phosphorus-containing flame retardant with high thermal stability, characterized in that It includes the following steps: Dissolve the transition metal salt and the phosphorus-containing substance in a solvent respectively, then mix and react. Set the reaction temperature at 150 °C to 180 °C, and the reaction time at 4 to 8 h. Collect the solid product, wash it, and dry it to prepare a phosphorus-containing high thermal stability flame retardant.

2. The preparation method of a phosphorus-containing high heat stability flame retardant according to claim 1, characterized in that, The transition metal element of the transition metal salt is any one or more of Fe, Co, Cu, Ni, Al, Mn, Cr, Mg, Ca, Zn or La; the phosphorus-containing substance is DOPO.

3. The preparation method of a phosphorus-containing high heat stability flame retardant according to claim 1, characterized in that, The transition metal salt is any one or more of iron acetylacetonate, cobalt acetylacetonate, copper acetylacetonate, nickel acetylacetonate, aluminum acetylacetonate, manganese acetylacetonate, chromium acetylacetonate, magnesium acetylacetonate, calcium acetylacetonate, zinc acetylacetonate or lanthanum acetylacetonate.

4. The preparation method of a phosphorus-containing high heat stability flame retardant according to claim 1, characterized in that, The molar ratio of the transition metal salt to the phosphorus-containing substance is (1:2) to (1:5).

5. The preparation method of a phosphorus-containing high heat stability flame retardant according to claim 1, characterized in that, The solvent is any one of dimethyl sulfoxide, N,N-dimethylformamide, N-methylpyrrolidone, and dimethylacetamide.

6. The preparation method of a phosphorus-containing high heat stability flame retardant according to claim 2, characterized in that, The synthesis route of the preparation method is shown in Formula (Ⅰ) or Formula (Ⅱ): Formula (Ⅰ) In the formula (Ⅰ), M is any one of Co, Cu, Ni, Mn, Mg, Ca or Zn; Formula (Ⅱ) In the formula (Ⅱ), M is any one of Fe, Al, Cr or La.

7. A phosphorus-containing flame retardant with high thermal stability, characterized in that It is prepared by the preparation method according to any one of claims 1 to 6.

8. Application of the phosphorus-containing high thermal stability flame retardant prepared by the preparation method according to any one of claims 1 to 6 or the phosphorus-containing high thermal stability flame retardant according to claim 7 in the synthesis of flame-retardant polycarbonate.

9. A method for synthesizing a flame-retardant polycarbonate, characterized in that, It includes the following steps: Step 1: After preparing the phosphorus-containing high thermal stability flame retardant by the preparation method according to any one of claims 1 to 6, dry it for standby; Step 2: Dry the pure polycarbonate masterbatch at 80 °C to 100 °C for standby; Step 3: Melt-blend the polycarbonate dried in Step 2 with the flame retardant prepared in Step 1. The mass ratio of the polycarbonate to the flame retardant is 100:(1 to 5). The temperature of the melt-blending is 200 °C to 250 °C, the rotation speed is 50 to 100 r / min, and the blending time is 10 to 15 min. Cool it, and the obtained product is the flame-retardant polycarbonate material.

10. A flame-retardant polycarbonate, characterized in that, It is synthesized by the synthesis method according to claim 9.

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