Application of Decabromodiphenylethane in the Preparation of Flame Retardant Resins

Abstract

The present invention relates to the technical field of flame retardant resins, specifically the application of decabromodiphenylethane in the preparation of flame retardant resins. With decabromodiphenylethane as the core, it is incorporated into the flame retardant resin. The method specifically comprises: uniformly blending nano-boron nitride, stearic acid-modified magnesium hydroxide, and zinc borate; adding a polyvinylpyrrolidone aqueous solution to the mixed powder, ultrasonically dispersing, and spray drying to obtain a composite powder; adding polypropylene, decabromodiphenylethane, the composite powder, maleic anhydride-grafted polypropylene, and an antioxidant to a high-speed mixer to obtain a mixture; setting an extruder temperature gradient, and melt blending, water cooling, and pelletizing the mixture to obtain a flame retardant resin masterbatch. With decabromodiphenylethane as the core, it is incorporated into the flame retardant resin, and by optimizing the amount of the flame retardant and the selection of a synergist, gas-phase-condensed-phase synergistic flame retardancy is achieved.

Description

Technical Field

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

[0002] Flame retardant resin is a resin material that has been technically processed to prevent or slow down the combustion rate. It can slow down the combustion rate or even self-extinguish in a fire, and reduce the production of toxic gases and smoke. It is widely used in electronics, transportation, building decoration and other fields.

[0003] Decabromodiphenyl ether (DBDE) is currently the most widely used and produced brominated flame retardant, and one of the most commonly used brominated flame retardants in flame-retardant resins. However, combustion or thermal decomposition of DBDE can produce polybrominated dibenzodioxins (PBDDs) and polybrominated dibenzofurans (PBDFs). These two substances are carcinogenic and teratogenic, leading to strict restrictions on their production and use.

[0004] Decabromodiphenylethane, a new additive flame retardant, does not produce polybrominated dibenzodioxins (PBDDs) or polybrominated dibenzofurans (PBDFs) upon combustion. Improving the flame retardant properties of flame-retardant resins using decabromodiphenylethane (DBDE) remains a pressing issue. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the present invention provides the use of decabromodiphenylethane in the preparation of flame retardant resin, aiming to improve the flame retardant properties of the flame retardant resin, which is specifically achieved through the following technical solutions:

[0006] Decabromodiphenylethane is used as the core and is incorporated into a flame retardant resin. The preparation method of the flame retardant resin comprises the following steps:

[0007] 1) uniformly blending 5 parts by weight of nano-boron nitride, 12 parts of stearic acid-modified magnesium hydroxide, and 1.5 parts of zinc borate, adding a 1.5 wt% aqueous solution of polyvinyl pyrrolidone to the mixed powder, and ultrasonically dispersing the mixture to obtain a uniform suspension;

[0008] 2) The suspension is spray-dried to obtain a composite powder;

[0009] 3) adding 100 parts of polypropylene, 20 parts of decabromodiphenylethane, 15 parts of composite powder, 8 parts of maleic anhydride grafted polypropylene, and 0.8 parts by weight of antioxidant into a high-speed mixer to obtain a mixture;

[0010] 4) The extruder temperature gradient is set, and the mixture is melt-blended, water-cooled, and pelletized to obtain a flame retardant resin masterbatch.

[0011] Preferably, the synthesis process of decabromodiphenylethane comprises the following steps:

[0012] 1) Add diphenylethane and bromine into the reactor at a molar ratio of 1: (10.5-14) and stir to allow the diphenylethane and bromine to be preliminarily mixed;

[0013] 2) Set the reactor temperature to 10°C, add catalyst A, continue stirring, and react for 2.5 hours;

[0014] 3) Raise the temperature to 30°C, add catalyst B, and continue the reaction for 3 to 3.5 hours;

[0015] 4) Raise the temperature to 50°C, add catalyst C, and continue the reaction for 3 to 3.5 hours. Then, raise the temperature to 75°C and keep the temperature for 15 hours to obtain a crude product.

[0016] 5) Control the temperature to ≤40°C, add NaOH solution to the crude product to neutralize the pH to 7.5-8, add 0.1%-1% complexing agent based on the weight of the crude product, stir for 15 minutes, wash three times with 80°C pure water, centrifuge, and collect the solid product;

[0017] 6) Stir the solid product with an ethanol-water mixed solvent at 80°C for 1 hour, cool to 25°C at a rate of 0.5°C / min, let stand for 12 hours, and filter to obtain a crystalline product;

[0018] 7) Collect the crystalline product, place it in a nitrogen-protected drying oven, dry it at 110°C for 2 hours, and air flow pulverize it to obtain the finished product of decabromodiphenylethane.

[0019] Preferably, the catalyst A is an Al-AlCl3 composite catalyst, and the amount used is 0.2% of the mass of diphenylethane.

[0020] Preferably, the molar ratio of Al to AlCl3 is 1:3.

[0021] Preferably, the catalyst B is a TiCl4-FeCl3 composite catalyst, and the amount used is 0.15% of the mass of diphenylethane.

[0022] Preferably, the molar ratio of TiCl4 to FeCl3 is 1:2.

[0023] Preferably, the catalyst C is antimony trichloride, and the amount used is 0.1% of the mass of diphenylethane.

[0024] Preferably, the complexing agent is disodium edetate.

[0025] After adopting the above technical solution, the beneficial effects of the present invention are:

[0026] Decabromodiphenylethane is used as the core and incorporated into flame-retardant resin. By optimizing the dosage of flame retardant and the selection of synergist, gas-condensed phase synergistic flame retardancy is achieved. While improving the flame retardant performance, it can maintain good tensile strength, flexural strength and impact toughness, meeting the material performance requirements of high-end application fields. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with 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 the need for some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present invention by illustrating examples of the present invention.

[0028] Example 1

[0029] This embodiment provides a method for preparing decabromodiphenylethane. The following are the specific steps and technical details.

[0030] Premixing

[0031] Add diphenylethane (DPE) and bromine to the reactor at a molar ratio of 1:10.5. Start mechanical stirring at 300 rpm to allow the DPE and bromine to initially mix.

[0032] Staged catalytic bromination reaction

[0033] 1) Low temperature bromination

[0034] The reactor temperature was set at 10°C, and an Al-AlCl3 composite catalyst (with a molar ratio of Al to AlCl3 of 1:3) was added at a rate of 0.2% of the mass of diphenylethane. The stirring speed was increased to 400 rpm, and the reaction was allowed to proceed for 2 to 2.5 hours.

[0035] This stage mainly completes the ortho-para substitution of 4-6 bromine atoms. AlCl3, as a Lewis acid catalyst, can promote the electrophilic substitution reaction of bromine, while Al powder enhances the catalytic efficiency through surface active sites. Al powder consumes HBr by-products to generate AlCl3, maintaining the acidity of the catalytic system.

[0036] 2) Medium temperature bromination

[0037] Raise the temperature to 30°C and add a TiCl4-FeCl3 composite catalyst (a molar ratio of 1:2). Increase the stirring speed to 500 rpm and continue the reaction for 3 to 3.5 hours. The TiCl4-FeCl3 composite catalyst should be added in three additions (0.15% by weight of diphenylethane each time), with 30-minute intervals between additions.

[0038] This stage mainly completes the meta-substitution of 7-9 bromine atoms through Ti 4+ with Fe 3+ The synergistic polarization of Fe 3+ Inhibit Al 3+ Inactivation, reducing side effects.

[0039] 3) High temperature bromination

[0040] Raise the temperature to 50°C and add antimony trichloride (SbCl3) at a rate of 0.1% of the mass of diphenylethane. Continue the reaction for 3 to 3.5 hours. When the reaction is complete, raise the temperature to 70 to 75°C and maintain for 1.5 hours to ensure complete reaction of the residual bromine to obtain a crude product.

[0041] This stage mainly completes the deep substitution of the last 1-2 bromine atoms. SbCl3 generates a strong Lewis acid SbBr3, which overcomes the steric hindrance and promotes the embedding of meta-bromine atoms.

[0042] Bromine recovery

[0043] The system was cooled to 50°C, and the vacuum pump (-0.095 MPa) was turned on to distill and recover the unreacted Br2 to obtain a crude product.

[0044] Neutralization and washing

[0045] The temperature of the reactor was controlled at ≤40℃, and NaOH solution (mass fraction 10%) was added to the reactor. The pH value was monitored in real time and adjusted to 7.5-8.0. Based on the mass of the crude product, 0.1% disodium ethylenediaminetetraacetic acid (disodium EDTA) was added to the complex metal ion (Al 3+ 、Sb 3+ The mixture was stirred for 15 minutes and washed three times with 80°C pure water. The solid product was collected by centrifugation at 4000 rpm for 10 minutes.

[0046] Solvent recrystallization

[0047] The solid product was stirred with an ethanol-water mixed solvent (volume ratio 7:3, the total amount was 4 times the mass of the solid product) at 80°C for 1 hour, cooled to 25°C at 0.5°C / min, allowed to stand for 12 hours, and filtered to obtain a crystalline product.

[0048] dry

[0049] The crystalline product was collected, placed in a nitrogen-protected drying oven, dried at 110° C. for 2 hours, and air flow crushed to obtain a finished decabromodiphenylethane product with a bromine content of 83.5%, a whiteness of 92, a purity of 99.3%, and a free bromine content of 56 ppm.

[0050] Example 2

[0051] Based on Example 1, this example provides a method for preparing decabromodiphenylethane. The following are the specific steps and technical details:

[0052] 1) Add diphenylethane and bromine into a reactor at a molar ratio of 1:12 and stir to allow the diphenylethane and bromine to be preliminarily mixed;

[0053] 2) Set the reactor temperature to 10°C, add Al-AlCl3 composite catalyst at a rate of 0.2% of the mass of diphenylethane, continue stirring, and react for 2 to 2.5 hours;

[0054] 3) Raise the temperature to 30°C, add TiCl4-FeCl3 composite catalyst at a dosage of 0.15% of the mass of diphenylethane, and continue the reaction for 3 to 3.5 hours;

[0055] 4) Raise the temperature to 50°C, add antimony trichloride, and continue the reaction for 3 to 3.5 hours. Then raise the temperature to 70°C and keep warm for 1.5 hours to obtain a crude product;

[0056] 5) Control the temperature to ≤40°C, add NaOH solution to the crude product to neutralize the pH to 7.5-8, add 0.5% disodium EDTA based on the weight of the crude product, stir for 15 minutes, wash three times with 80°C pure water, centrifuge, and collect the solid product;

[0057] 6) Stir the solid product with an ethanol-water mixed solvent at 80°C for 1 hour, cool to 25°C at a rate of 0.5°C / min, let stand for 12 hours, and filter to obtain a crystalline product;

[0058] 7) The crystalline product was collected, dried in a nitrogen-protected drying oven at 110°C for 2 hours, and then air-pulverized to obtain a finished decabromodiphenylethane product having a bromine content of 84.3%, a brightness of 91, a purity of 99.2%, and a free bromine content of 50 ppm.

[0059] Example 3

[0060] Based on Example 1, this example provides a method for preparing decabromodiphenylethane. The following are the specific steps and technical details:

[0061] 1) Add diphenylethane and bromine into a reactor at a molar ratio of 1:14 and stir to allow the diphenylethane and bromine to be preliminarily mixed;

[0062] 2) The reactor temperature was set at 10°C, Al-AlCl3 composite catalyst was added, stirring continuously, and the reaction was carried out for 2 to 3 hours;

[0063] 3) Raise the temperature to 30°C, add TiCl4-FeCl3 composite catalyst, and continue the reaction for 3 to 3.5 hours;

[0064] 4) Raise the temperature to 50°C, add antimony trichloride, and continue the reaction for 3 to 3.5 hours. Then raise the temperature to 70°C and keep warm for 1.5 hours to obtain a crude product;

[0065] 5) Control the temperature to ≤40°C, add NaOH solution to the crude product to neutralize the pH to 7.5-8, add 1% disodium EDTA based on the weight of the crude product, stir for 15 minutes, wash three times with 80°C pure water, centrifuge, and collect the solid product;

[0066] 6) Stir the solid product with an ethanol-water mixed solvent at 80°C for 1 hour, cool to 25°C at a rate of 0.5°C / min, let stand for 12 hours, and filter to obtain a crystalline product;

[0067] 7) The crystalline product was collected, dried in a nitrogen-protected drying oven at 110°C for 2 hours, and then air-pneumatically crushed to obtain a finished decabromodiphenylethane product having a bromine content of 85.1%, a brightness of 94, a purity of 99.5%, and a free bromine content of 48 ppm.

[0068] Decabromodiphenylethane (DBDPE) obtained in Example 1-3 is used as the core and incorporated into a flame retardant resin. The following are the specific steps and technical details of the method for preparing a high-efficiency flame retardant resin based on decabromodiphenylethane.

[0069] Step 1: Decabromodiphenylethane modification

[0070] 20 parts of DBDPE powder were mixed with ethanol at a mass ratio of 1:5, and 0.6 parts of silane coupling agent KH-560 were added. Ultrasonic dispersion was performed to activate the surface hydroxyl groups of the DBDPE. Acetic acid solution (20% by mass) was added dropwise to adjust the pH to 4-5. The mixture was reacted at 70°C for 4 hours to complete the grafting of the silane coupling agent onto the DBDPE surface and enhance its compatibility with the resin matrix. The product was centrifuged, washed with ethanol, and then vacuum-dried at 80°C for 12 hours to obtain surface-modified KH-DBDPE.

[0071] Step 2: Preparation of composite powder

[0072] 5 parts by weight of nano-boron nitride (BN), 12 parts of stearic acid-modified magnesium hydroxide (MH), and 1.5 parts of zinc borate (ZB) were uniformly blended. A 1.5 wt% aqueous solution of polyvinylpyrrolidone (PVP) was added to the mixed powder and ultrasonically dispersed to obtain a uniform suspension. The suspension was then spray-dried at an inlet temperature of 160-170°C and an outlet temperature of 90-100°C to obtain a composite powder.

[0073] The pyrrolidone groups in the PVP molecule adsorb onto the BN surface through hydrogen bonding, with the long chains encapsulating the MH particles to form a composite structure, achieving synergistic gas-phase and condensed-phase flame retardancy. When PVP thermally decomposes at high temperatures, the pyrrolidone rings crack, releasing nitrogen-containing free radicals (such as NH2), which can capture active free radicals (such as H and OH) in the combustion chain reaction, further inhibiting flame propagation.

[0074] The decomposition of MH absorbs a significant amount of heat, lowering the material's surface temperature. The released water vapor dilutes the oxygen concentration in the combustion zone, inhibiting the combustion chain reaction. MgO generated by MH decomposition reacts with acidic gases such as HCl produced by the cracking of the product, reducing the release of toxic fumes and corrosive gases. MgO generated by BN decomposition coats the carbon layer, enhancing its oxidation resistance and thermal stability. ZB and MgO generated by the decomposition of MH form a protective magnesium borate glass layer, enhancing the density of the carbon layer.

[0075] Step 3: Premixing of raw materials

[0076] By weight, 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 parts of antioxidant Irganox 1010 were added to a high-speed mixer and premixed at 800 rpm for 15 minutes.

[0077] Step 4: Extrusion

[0078] The extruder temperature gradient was set at 180°C in zone 1 (feeding zone), 200°C in zone 2 (melting zone), 210°C in zone 3 (impregnation zone), and 200°C in zone 4 (homogenization zone). The die temperature was set at 190°C. Intermittent ultrasonic waves at 40kHz and 500W (5s on / 10s off) were applied during the extrusion process. The resulting product was then water-cooled and pelletized to produce a flame-retardant resin masterbatch.

[0079] The maleic anhydride groups of PP-g-MAH react with the epoxy groups of KH-DBDPE at high temperatures to form a stable ester bond, effectively inhibiting the migration and precipitation of decabromodiphenylethane during long-term use. Ultrasonic waves applied during the extrusion process impact the BN sheet aggregates, causing them to exfoliate into single or few-layer structures, forming a three-dimensional thermally conductive network. Simultaneously, ultrasonic vibrations enhance melt fluidity and promote the penetration and bonding of BN into the PP matrix. The ultrasonic cavitation effect uniformly embeds the BN into the resin matrix, forming a three-dimensional thermally conductive network and enhancing flame retardancy and thermal stability.

[0080] By the same preparation method, flame retardant resins without flame retardant and without composite powder were prepared as control groups, respectively recorded as Comparative Example 1 (without decabromodiphenylethane flame retardant) and Comparative Example 2 (without composite powder).

[0081] A predetermined amount of flame-retardant resin masterbatch was formed into standard test specimens using a hot press (pressure 10 MPa, temperature 190°C, holding pressure for 5 minutes). The performance of the standard test specimens was tested, and the results are shown in the following table.

[0082]

[0083] The addition of DBDPE to Examples 1-3 and Comparative Example 2 significantly improved LOI. For Examples 1-3, thanks 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 forms a thermally conductive network to slow thermal diffusion, MH absorbs heat and decomposes to inhibit combustion, and ZB forms a glassy protective layer, enhancing the flame retardancy of the substrate.

[0084] In Comparative Example 2, the addition of DBDPE disrupts the crystalline structure of PP, reducing crystallinity and, consequently, HDT (heat distortion temperature). The improved HDT in Examples 1-3 is attributed to the addition of composite powders. MH improves compatibility with PP, reduces agglomeration, and minimizes damage to crystallinity. Dispersed BN rapidly conducts heat, reduces localized thermal stress, and delays thermal deformation. BN also acts as a nucleating agent, promoting PP crystallization and increasing crystallinity, thereby improving HDT. ZB promotes the formation of a char layer, protecting the substrate from high temperatures.

[0085] While the embodiments of the present invention are described above, these embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Clearly, many modifications and variations can be made based on the above description. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to make good use of the present invention and its modifications and uses. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. Application of decabromodiphenylethane in the preparation of flame retardant resin, characterized by: Decabromodiphenylethane is used as the core and is incorporated into a flame retardant resin. The preparation method of the flame retardant resin comprises the following steps: 1) uniformly blending 5 parts by weight of nano-boron nitride, 12 parts of stearic acid-modified magnesium hydroxide, and 1.5 parts of zinc borate, adding a 1.5 wt% aqueous solution of polyvinyl pyrrolidone to the mixed powder, and ultrasonically dispersing the mixture to obtain a uniform suspension; 2) The suspension is spray-dried to obtain a composite powder; 3) adding 100 parts of polypropylene, 20 parts of decabromodiphenylethane, 15 parts of composite powder, 8 parts of maleic anhydride grafted polypropylene, and 0.8 parts of antioxidant into a high-speed mixer to obtain a mixture; 4) The extruder temperature gradient is set, and the mixture is melt-blended, water-cooled, and pelletized to obtain a flame retardant resin masterbatch.

2. The use of decabromodiphenylethane in the preparation of flame retardant resin according to claim 1, characterized in that: The synthesis process of decabromodiphenylethane comprises the following steps: 1) Add diphenylethane and bromine into the reactor at a molar ratio of 1: (10.5-14) and stir to allow the diphenylethane and bromine to be preliminarily mixed; 2) Set the reactor temperature to 10°C, add catalyst A, continue stirring, and react for 2 to 2.5 hours; 3) Raise the temperature to 30°C, add catalyst B, and continue the reaction for 3 to 3.5 hours; 4) Raise the temperature to 50°C, add catalyst C, and continue the reaction for 3 to 3.5 hours. Then raise the temperature to 70°C and keep warm for 1 hour to obtain a crude product; 5) Control the temperature to ≤40°C, add NaOH solution to the crude product to neutralize the pH to 7.5-8, add 0.1%-1% complexing agent based on the weight of the crude product, stir for 15 minutes, wash three times with 80°C pure water, centrifuge, and collect the solid product; 6) Stir the solid product with an ethanol-water mixed solvent at 80°C for 1 hour, cool to 25°C at a rate of 0.5°C / min, let stand for 12 hours, and filter to obtain a crystalline product; 7) Collect the crystalline product, place it in a nitrogen-protected drying oven, dry it at 110°C for 2 hours, and air flow pulverize it to obtain the finished product of decabromodiphenylethane.

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

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

3.

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

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

2.

7. The use of decabromodiphenylethane in the preparation of flame retardant resin according to claim 2, characterized in that: The catalyst C is antimony trichloride, and the amount used is 0.1% of the mass of diphenylethane.

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

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