Application of decabromodiphenylethane in preparation of flame-retardant resin

Abstract

The invention relates to the technical field of flame-retardant resin, in particular to application of decabromodiphenylethane in preparation of flame-retardant resin.The decabromodiphenylethane serves as a core, the decabromodiphenylethane is doped into the flame-retardant resin, and the preparation method specifically comprises the steps that nanometer boron nitride, stearic acid modified magnesium hydroxide and zinc borate are evenly blended, a polyvinylpyrrolidone aqueous solution is added into mixed powder, ultrasonic dispersion is conducted, and a mixture is obtained; spraying and drying to obtain composite powder; adding polypropylene, decabromodiphenyl ethane, the composite powder, maleic anhydride grafted polypropylene and an antioxidant into a high-speed mixer to obtain a mixture; and setting the temperature gradient of an extruder, and carrying out melt blending, water cooling and pelletizing on the mixture to obtain the flame-retardant resin master batch. The decabromodiphenyl ethane is taken as a core and is doped into the flame-retardant resin, and gas phase-condensed phase synergistic flame retardance is realized by optimizing the dosage of a flame retardant and selecting a synergist.

Description

Technical Field

[0001] The present invention relates to the technical field of flame-retardant resins, and specifically to the application of decabromodiphenylethane in the preparation of flame-retardant resins. Background Art

[0002] A flame-retardant resin is a resin material that can prevent or slow down the combustion rate through technical treatment. It can slow down the combustion rate or even self-extinguish in a fire and reduce the generation of toxic gases and smoke. It is widely used in the fields of electronics and electricity, transportation, building decoration, etc.

[0003] Decabromodiphenyl ether is the most widely used and largest-output important brominated flame retardant at present, and is one of the most commonly used brominated flame retardants in the field of flame-retardant resins. However, decabromodiphenyl ether may produce polybrominated dibenzo-p-dioxins and polybrominated dibenzofurans during combustion or thermal cracking. These two substances are carcinogenic and teratogenic, which makes its production and use face strict restrictions.

[0004] As a new type of additive flame retardant, decabromodiphenylethane does not produce polybrominated dibenzo-p-dioxins and polybrominated dibenzofurans during combustion. How to use it in flame-retardant resins to improve the flame retardancy of flame-retardant resins is an urgent problem to be solved. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the present invention provides the application of decabromodiphenylethane in the preparation of flame-retardant resins, aiming to improve the flame retardancy of flame-retardant resins. Specifically, it is achieved through the following technical solutions: With decabromodiphenylethane as the core, it is incorporated into the flame-retardant resin. The preparation method of the flame-retardant resin includes the following steps: 1) By weight, 5 parts of nano boron nitride, 12 parts of stearic acid-modified magnesium hydroxide, and 1.5 parts of zinc borate are uniformly blended. 1.5 wt% of polyvinylpyrrolidone aqueous solution is added to the mixed powder, and ultrasonic dispersion is carried out to obtain a uniform suspension; 2) The suspension is spray-dried to obtain a composite powder; 3) 100 parts of polypropylene, 20 parts of decabromodiphenylethane, 15 parts of the composite powder, 8 parts of maleic anhydride-grafted polypropylene, and 0.8 parts by weight of antioxidant are added to a high-speed mixer to obtain a mixture; 4) The temperature gradient of the extruder is set, and the mixture is melt-blended, water-cooled, and pelletized to obtain a flame-retardant resin masterbatch.

[0006] Preferably, the synthesis process of the decabromodiphenylethane includes the following steps: 1) Diphenylethane and bromine are put into a reaction kettle according to a molar ratio of 1∶(10.5 - 14), and stirred to preliminarily mix diphenylethane and bromine; 2) The temperature of the reaction kettle is set to 10°C, catalyst A is added, and continuous stirring is carried out for 2.5 hours; 3) Heat up to 30 °C, add catalyst B, and continue the reaction for 3 - 3.5 hours; 4) Heat up to 50 °C, add catalyst C, and continue the reaction for 3 - 3.5 hours. Then heat up to 75 °C and keep the temperature for 15 hours to obtain the crude product; 5) Control the temperature ≤ 40 °C, add NaOH solution to the crude product, neutralize the pH to 7.5 - 8, add 0.1% - 1% complexing agent based on the mass of the crude product, stir for 15 minutes, wash three times with pure water at 80 °C, centrifuge, and collect the solid product; 6) Stir the solid product with an ethanol - water mixed solvent at 80 °C for 1 hour, cool down to 25 °C at a rate of 0.5 °C / min, stand for 12 hours, and filter to obtain the crystalline product; 7) Collect the crystalline product, place it in a drying oven under nitrogen protection, dry at 110 °C for 2 hours, and perform airflow pulverization to obtain the finished product of decabromodiphenylethane.

[0007] Preferably, the catalyst A is an Al - AlCl3 composite catalyst, and the dosage is 0.2% of the mass of diphenylethane.

[0008] Preferably, the molar ratio of Al to AlCl3 is 1:3.

[0009] Preferably, the catalyst B is a TiCl4 - FeCl3 composite catalyst, and the dosage is 0.15% of the mass of diphenylethane.

[0010] Preferably, the molar ratio of TiCl4 to FeCl3 is 1:2.

[0011] Preferably, the catalyst C is antimony trichloride, and the dosage is 0.1% of the mass of diphenylethane.

[0012] Preferably, the complexing agent is disodium ethylenediaminetetraacetate.

[0013] After adopting the above - mentioned technical solutions, the beneficial effects of the present invention are as follows: With decabromodiphenylethane as the core, incorporating it into the flame - retardant resin, through optimizing the dosage of the flame - retardant and the selection of synergists, realizing gas - phase - condensed - phase synergistic flame retardancy, while improving the flame - retardant performance, it can maintain good tensile strength, flexural strength and impact toughness, meeting the requirements of material properties in high - end application fields. Detailed implementation mode

[0014] To make the objectives, technical solutions and advantages of the present invention more clearly understood, the following further describes the present invention in detail with reference to specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are not configured to limit the present invention. For those skilled in the art, the present invention can be implemented without some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by showing examples of the present invention.

[0015] Example 1 This embodiment provides a preparation method of decabromodiphenylethane, and the following are its specific steps and technical details.

[0016] Feeding and premixing Add diphenylethane (DPE) and bromine into the reaction kettle with a molar ratio of 1:10.5. Start mechanical stirring at a speed of 300 rpm to preliminarily mix DPE and bromine.

[0017] Staged catalytic bromination reaction 1) Low-temperature bromination Set the temperature of the reaction kettle to 10°C, add an Al-AlCl3 composite catalyst (molar ratio of Al to AlCl3 is 1:3), and the dosage is 0.2% of the mass of diphenylethane. Increase the stirring speed to 400 rpm and react for 2 - 2.5 hours.

[0018] This stage mainly completes the ortho-para substitution of 4 - 6 bromine atoms. As a Lewis acid catalyst, AlCl3 can promote the electrophilic substitution reaction of bromine, while Al powder enhances the catalytic efficiency through surface active sites. Al powder generates AlCl3 by consuming the HBr by-product to maintain the acidity of the catalytic system.

[0019] 2) Medium-temperature bromination Raise the temperature to 30°C, add a TiCl4-FeCl3 composite catalyst (molar ratio of TiCl4 to FeCl3 is 1:2), increase the stirring speed to 500 rpm, and continue to react for 3 - 3.5 hours. The dosage of the TiCl4-FeCl3 composite catalyst is 0.15% of the mass of diphenylethane, and it is added in three times (each dosage is 0.05% of the mass of diphenylethane), with an interval of 30 minutes each time.

[0020] This stage mainly completes the meta-substitution of 7 - 9 bromine atoms. The synergistic polarization effect of Ti 4+ and Fe 3+ promotes meta-bromination, and at the same time, Fe 3+ inhibits the inactivation of Al 3+ and reduces side reactions.

[0021] 3) High-temperature bromination Heat up to 50 °C, add antimony trichloride (SbCl3) in an amount of 0.1% of the mass of diphenylethane, and continue the reaction for 3 to 3.5 hours. After the reaction is completed, heat up to 70 - 75 °C and keep the temperature for 1.5 hours to ensure that the residual bromine is completely reacted to obtain the crude product.

[0022] This stage mainly completes the deep substitution of the last 1 - 2 bromine atoms. SbCl3 generates strong Lewis acid SbBr3, overcomes steric hindrance, and promotes the embedding of meta - bromine atoms.

[0023] Bromine recovery Cool the system to 50 °C, turn on the vacuum pump (-0.095 MPa) to distill and recover the unreacted Br2 to obtain the crude product.

[0024] Neutralization and washing Control the temperature of the reaction kettle ≤ 40 °C, add NaOH solution (mass fraction 10%) to the reaction kettle, monitor the pH value in real - time, and adjust the target to 7.5 - 8.0. Based on the mass of the crude product, add 0.1% disodium ethylenediaminetetraacetate (EDTA disodium) to complex metal ions (Al 3+ 、Sb 3+ etc.) to prevent catalytic residues from causing subsequent thermal decomposition. Stir for 15 minutes, wash three times with pure water at 80 °C. Centrifuge at 4000 rpm for 10 minutes to collect the solid product.

[0025] Solvent recrystallization Mix the solid product with an ethanol - water mixed solvent (volume ratio 7:3, total amount used is 4 times the mass of the solid product), stir at 80 °C for 1 hour, cool down to 25 °C at a rate of 0.5 °C / min, stand for 12 hours, and filter to obtain the crystalline product.

[0026] Drying Collect the crystalline product, place it in a drying oven under nitrogen protection, dry at 110 °C for 2 hours, and perform airflow pulverization to obtain the finished product of decabromodiphenylethane with a bromine content of 83.5%, whiteness of 92, purity of 99.3%, and free bromine of 56 ppm.

[0027] Example 2 On the basis of Example 1, this example provides a preparation method of decabromodiphenylethane. The following are its specific steps and technical details: 1) Charge diphenylethane and bromine into the reaction kettle according to a molar ratio of 1:12, stir to make the diphenylethane and bromine preliminarily mixed; 2) Set the temperature of the reaction kettle to 10 °C, add an Al - AlCl3 composite catalyst in an amount of 0.2% of the mass of diphenylethane, continuously stir, and react for 2 - 2.5 hours; 3) Heat up to 30°C, add the TiCl4-FeCl3 composite catalyst with a dosage of 0.15% of the mass of diphenylethane, and continue the reaction for 3 - 3.5 hours; 4) Heat up to 50°C, add antimony trichloride, continue the reaction for 3 - 3.5 hours, then heat up to 70°C and keep the temperature for 1.5 hours to obtain the crude product; 5) Control the temperature ≤ 40°C, add NaOH solution to the crude product, neutralize the pH to 7.5 - 8, add 0.5% disodium ethylenediaminetetraacetate based on the mass of the crude product, stir for 15 minutes, wash three times with pure water at 80°C, centrifuge, and collect the solid product; 6) Stir the solid product with the ethanol-water mixed solvent at 80°C for 1 hour, cool down to 25°C at a rate of 0.5°C / min, let it stand for 12 hours, and filter to obtain the crystalline product; 7) Collect the crystalline product, place it in a drying oven under nitrogen protection, dry at 110°C for 2 hours, and pulverize with air flow to obtain the finished product of decabromodiphenylethane with a bromine content of 84.3%, whiteness of 91, purity of 99.2%, and free bromine of 50 ppm.

[0028] Example 3 Based on Example 1, this example provides a preparation method of decabromodiphenylethane. The following are the specific steps and technical details: 1) Charge diphenylethane and bromine into the reaction kettle according to a molar ratio of 1:14, stir to make the diphenylethane and bromine preliminarily mixed; 2) Set the temperature of the reaction kettle to 10°C, add the Al-AlCl3 composite catalyst, continuously stir, and react for 2 - 3 hours; 3) Heat up to 30°C, add the TiCl4-FeCl3 composite catalyst, and continue the reaction for 3 - 3.5 hours; 4) Heat up to 50°C, add antimony trichloride, continue the reaction for 3 - 3.5 hours, then heat up to 70°C and keep the temperature for 1.5 hours to obtain the crude product; 5) Control the temperature ≤ 40°C, add NaOH solution to the crude product, neutralize the pH to 7.5 - 8, add 1% disodium ethylenediaminetetraacetate based on the mass of the crude product, stir for 15 minutes, wash three times with pure water at 80°C, centrifuge, and collect the solid product; 6) Stir the solid product with the ethanol-water mixed solvent at 80°C for 1 hour, cool down to 25°C at a rate of 0.5°C / min, let it stand for 12 hours, and filter to obtain the crystalline product; 7) Collect the crystalline product, place it in a drying oven under nitrogen protection, dry at 110°C for 2 hours, and pulverize with air flow to obtain the finished product of decabromodiphenylethane with a bromine content of 85.1%, whiteness of 94, purity of 99.5%, and free bromine of 48 ppm.

[0029] Taking the decabromodiphenylethane (DBDPE) obtained in Examples 1 - 3 as the core, and incorporating it into the flame - retardant resin, the following are the specific steps and technical details of the preparation method of the highly efficient flame - retardant resin based on decabromodiphenylethane.

[0030] Step 1: Modification of decabromodiphenylethane By weight, mix 20 parts of DBDPE powder with ethanol at a mass ratio of 1:5, add 0.6 part of silane coupling agent KH - 560, and perform ultrasonic dispersion to activate the surface hydroxyl groups of DBDPE. Dropwise add acetic acid solution (mass fraction 20%) to adjust the pH to 4 - 5, and react at 70 °C for 4 hours to complete the grafting of the silane coupling agent on the surface of DBDPE, enhancing its compatibility with the resin matrix. Centrifuge the product, wash it with ethanol, and then dry it under vacuum at 80 °C for 12 hours to obtain surface - modified KH - DBDPE.

[0031] Step 2: Preparation of composite powder By weight, uniformly blend 5 parts of nano - boron nitride (BN), 12 parts of stearic - acid - modified magnesium hydroxide (MH), and 1.5 parts of zinc borate (ZB). Add 1.5 wt% aqueous solution of polyvinylpyrrolidone (PVP) to the mixed powder and perform ultrasonic dispersion to obtain a uniform suspension. Spray - dry the suspension with parameters of inlet temperature 160 - 170 °C and outlet temperature 90 - 100 °C to obtain the composite powder.

[0032] The pyrrolidone group in the PVP molecule adsorbs on the surface of BN through hydrogen - bond interaction, and the long chain coats the MH particles, forming a composite structure to achieve gas - phase - condensed - phase synergistic flame retardancy. When PVP thermally decomposes at high temperature, the pyrrolidone ring cracks, releasing nitrogen - containing free radicals (such as ·NH2), which can capture active free radicals (such as ·H, ·OH) in the combustion chain reaction, further inhibiting flame propagation.

[0033] A large amount of heat is absorbed during the decomposition process of MH, reducing the surface temperature of the material. The released water vapor dilutes the oxygen concentration in the combustion zone, inhibiting the combustion chain reaction. The MgO generated by the decomposition of MH reacts with acidic gases such as HCl produced by the pyrolysis of the product, reducing the release of toxic smoke and corrosive gases. The MgO generated by the decomposition of BN covers the surface of the carbon layer, enhancing the antioxidant and thermal stability of the carbon layer. ZB forms a magnesium borate glassy protective layer with the MgO generated by the decomposition of MH, enhancing the denseness of the carbon layer.

[0034] Step 3: Premixing of raw materials By weight, add 100 parts of polypropylene (PP), 20 parts of KH - DBDPE, 15 parts of composite powder, 8 parts of maleic - anhydride - grafted polypropylene (PP - g - MAH), and 0.8 part of antioxidant Irganox 1010 to a high - speed mixer and premix at 800 rpm for 15 minutes.

[0035] Step 4. Extrusion Molding Set the temperature gradient of the extruder: Zone 1 (feeding zone) 180 °C, Zone 2 (melting zone) 200 °C, Zone 3 (impregnation zone) 210 °C, Zone 4 (homogenization zone) 200 °C, and the die head 190 °C. Apply intermittent ultrasonic waves of 40 kHz and 500 W (5 s on / 10 s off) during the extrusion process, and obtain the flame-retardant resin masterbatch through water cooling and pelletizing.

[0036] The maleic anhydride groups of PP-g-MAH react with the epoxy groups of KH-DBDPE at high temperature to form stable ester bonds, effectively inhibiting the migration and precipitation of decabromodiphenylethane during long-term use. The ultrasonic waves applied during the extrusion process can impact the BN lamellar aggregates, stripping them into single-layer or few-layer structures to form a three-dimensional heat conduction network. At the same time, the ultrasonic vibration enhances the melt fluidity and promotes the penetration and combination of BN and the PP matrix. The ultrasonic cavitation effect enables BN to be evenly embedded in the resin matrix to form a three-dimensional heat conduction network, improving the flame retardancy and thermal stability.

[0037] Using the same preparation method, flame-retardant resins without flame retardants and without composite powders were respectively prepared as control groups, denoted as Comparative Example 1 (without decabromodiphenylethane flame retardant) and Comparative Example 2 (without composite powder).

[0038] A fixed quantity of the flame-retardant resin masterbatch was formed into standard test specimens by a hot press (pressure 10 MPa, temperature 190 °C, holding pressure for 5 minutes), and the performance of the standard test specimens was respectively detected. The results are shown in the following table.

[0039]

[0040] In Examples 1-3 and Comparative Example 2, DBDPE was added, and the LOI was significantly improved. For Examples 1-3, due to the high bromine content of DBDPE and the synergistic effect of the composite powder, the LOI was significantly higher than that of Comparative Example 2. BN can form a heat conduction network to delay heat diffusion, MH can absorb heat and decompose to inhibit combustion, and ZB can generate a vitreous protective layer, improving the flame retardancy efficiency of the matrix.

[0041] In Comparative Example 2, the addition of DBDPE will damage the crystalline structure of PP and reduce the crystallinity, thereby reducing the HDT (heat distortion temperature). The reason for the increase in HDT in Examples 1-3 is the addition of the composite powder. MH can improve the compatibility with PP, reduce agglomeration, and reduce the damage to crystallinity. Dispersed BN can quickly conduct heat, reduce local thermal stress, and delay thermal deformation. BN can also act as a nucleating agent to promote the crystallization of PP and increase the crystallinity, thereby increasing the HDT. ZB promotes the formation of a carbon layer to protect the matrix from high temperature effects.

[0042] In accordance with the embodiments of the present invention as described above, these embodiments do not exhaustively describe all the details and do not limit the invention to only the specific embodiments. Obviously, many modifications and variations can be made according to the above description. The present specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can make good use of the present invention and its modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. Application of decabromodiphenylethane in preparation of flame-retardant resin, characterized in that: With decabromodiphenylethane as the core, it is incorporated into a flame-retardant resin. The preparation method of the flame-retardant resin includes the following steps: 1) By weight, 5 parts of nano boron nitride, 12 parts of stearic acid-modified magnesium hydroxide, and 1.5 parts of zinc borate are uniformly blended. An aqueous solution of 1.5 wt% polyvinylpyrrolidone is added to the mixed powder, and ultrasonic dispersion is carried out to obtain a uniform suspension; 2) The suspension is spray-dried to obtain a composite powder; 3) 100 parts of polypropylene, 20 parts of decabromodiphenylethane, 15 parts of the composite powder, 8 parts of maleic anhydride-grafted polypropylene, and 0.8 part of antioxidant are added to a high-speed mixer to obtain a mixture; 4) The temperature gradient of the extruder is set, and the mixture is melt-blended, water-cooled, and pelletized to obtain a flame-retardant resin masterbatch.

2. The application of decabromodiphenylethane according to claim 1 in the preparation of flame-retardant resin, characterized in that, The synthesis process of the decabromodiphenylethane includes the following steps: 1) Diphenylethane and bromine are put into a reaction kettle according to a molar ratio of 1∶(10.5 - 14), and stirred to preliminarily mix diphenylethane and bromine; 2) The temperature of the reaction kettle is set to 10°C, catalyst A is added, and continuous stirring is carried out for 2 - 2.5 hours; 3) The temperature is raised to 30°C, catalyst B is added, and the reaction continues for 3 - 3.5 hours; 4) The temperature is raised to 50°C, catalyst C is added, and the reaction continues for 3 - 3.5 hours. Subsequently, the temperature is raised to 70°C and kept warm for 1 hour to obtain a crude product; 5) The temperature is controlled ≤40°C, an NaOH solution is added to the crude product to neutralize the pH to 7.5 - 8, and based on the mass of the crude product, 0.1% - 1% complexing agent is added. Stir for 15 minutes, wash three times with pure water at 80°C, and centrifuge to collect the solid product; 6) The solid product is stirred with an ethanol-water mixed solvent at 80°C for 1 hour, cooled to 25°C at a rate of 0.5°C / min, and left standing for 12 hours, and then filtered to obtain a crystalline product; 7) The crystalline product is collected, placed in a drying oven under nitrogen protection, dried at 110°C for 2 hours, and air pulverized to obtain the finished product of decabromodiphenylethane.

3. The application of decabromodiphenylethane according to claim 2 in the preparation of flame-retardant resin, characterized in that: The catalyst A is an Al-AlCl3 composite catalyst, and the dosage is 0.2% of the mass of diphenylethane.

4. The application of decabromodiphenylethane according to claim 3 in the preparation of flame-retardant resin, characterized in that: The molar ratio of Al to AlCl3 is 1∶3.

5. The application of decabromodiphenylethane according to claim 2 in the preparation of flame-retardant resin, characterized in that: The catalyst B is a TiCl4-FeCl3 composite catalyst, and the dosage is 0.15% of the mass of diphenylethane.

6. The application of decabromodiphenylethane according to claim 5 in the preparation of flame-retardant resin, characterized in that: The molar ratio of TiCl4 to FeCl3 is 1∶2.

7. Use of decabromodiphenylethane according to claim 2 in the preparation of flame-retardant resins, characterized in that: The catalyst C is antimony trichloride, and the dosage is 0.1% of the mass of diphenylethane.

8. The application of decabromodiphenylethane according to claim 2 in the preparation of flame-retardant resin, characterized in that: The complexing agent is disodium ethylenediaminetetraacetate.

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