Halogen-free flame-retardant PC / ABS alloy and preparation method thereof
By using APP@melamine-tannic acid-Fe flame retardant and DOPO-polyborosiloxane synergist in PC/ABS alloys, the problems of flammability and performance degradation of PC/ABS alloys were solved, achieving simultaneous improvement in halogen-free flame retardant performance and mechanical properties, and expanding its application range.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TAIHE BAIYUN PLASTICS CO LTD
- Filing Date
- 2026-03-25
- Publication Date
- 2026-05-12
AI Technical Summary
The flammability of existing PC/ABS alloys and the degradation of heat resistance and mechanical properties caused by the addition of flame retardants make them difficult to widely use in fields with high safety requirements.
Using APP@melamine-tannic acid-Fe as a flame retardant and combining it with DOPO-polyborosiloxane as a flame retardant synergist, the interfacial compatibility is improved through chemical bonding and physical entanglement, forming a stable expanded char layer and achieving halogen-free flame retardancy.
While ensuring good mechanical properties of the material, the flame retardant efficiency has been significantly improved, expanding its application in high-end electronic appliances and new energy vehicles.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of PC / ABS alloy technology, specifically relating to a halogen-free flame-retardant PC / ABS alloy and its preparation method. Background Technology
[0002] Polycarbonate / (acrylonitrile-butadiene-styrene) copolymer (PC / ABS) alloy is an important thermoplastic engineering plastic. Its comprehensive performance benefits from the excellent heat resistance, dimensional stability, and impact toughness provided by the polycarbonate component, and the good processing flow and surface gloss imparted by the ABS resin component. Based on these performance advantages, this alloy material has been widely used in automotive manufacturing, electronics, building materials, and other fields. However, the inherent flammability of PC / ABS alloy has become a key obstacle restricting its application in fields with higher safety requirements. Specifically, during combustion, the flame spreads rapidly and is accompanied by the release of large amounts of harmful gases and smoke, which seriously limits the further expansion of its application range due to the resulting fire safety hazards.
[0003] To address the flammability of PC / ABS alloys, existing technologies primarily rely on adding flame retardants to impart flame-retardant properties, self-extinguishing characteristics, and smoke suppression capabilities. Early widely used halogenated flame retardants, such as decabromodiphenyl ether and tetrabromobisphenol A, while exhibiting high flame-retardant efficiency, pose increasingly prominent environmental and health risks: they produce large amounts of smoke during combustion, and the released hydrogen halide gases readily absorb moisture to form highly corrosive hydrohalic acids, causing secondary damage. Furthermore, some bromine-based flame retardants pose a risk of degradation during heat treatment, generating highly toxic byproducts such as polybrominated dibenzodioxanes (PBDDs) and polybrominated dibenzofurans (PBDFs). Given increasingly stringent environmental regulations and the trend towards green manufacturing, halogen-free flame retardancy has become the mainstream direction for flame-retardant modification of PC / ABS alloys.
[0004] In halogen-free flame retardant technology systems, phosphate esters are widely studied due to their good flame retardant efficiency and relatively excellent environmental compatibility. Their flame retardant mechanism mainly involves promoting char formation in the condensed phase and capturing free radicals in the gas phase. However, traditional phosphate ester flame retardants, including triphenyl phosphate (TPP), resorcinol bis(diphenyl phosphate) (RDP), and bisphenol A bis(diphenyl phosphate) (BDP), have significant technical limitations when applied to PC / ABS alloys. To achieve the UL94V-0 flame retardant rating, the addition amount of phosphate ester flame retardants typically needs to reach 10-15 wt% or more. This high addition amount highlights the compatibility issues between the flame retardant and the polycarbonate matrix: the disruption of hydrogen bonds and van der Waals forces between polycarbonate molecular chains by phosphate ester molecules reduces the molecular chain entanglement density, resulting in a significant decrease in the material's heat distortion temperature and a deterioration in heat resistance; simultaneously, the small-molecule plasticizing effect of phosphate esters and the interfacial defects they induce hinder the energy dissipation mechanism under impact loads, leading to a significant reduction in the material's notched impact strength. In addition, the addition of high-content phosphate esters may also cause problems such as excessively low melt viscosity, decreased dimensional stability during processing, surface precipitation, and reduced hydrolysis resistance.
[0005] In summary, while existing phosphate ester flame retardant systems improve the flame retardant properties of PC / ABS alloys, they often sacrifice the inherent heat resistance and mechanical properties of the materials. Maintaining high flame retardancy while effectively suppressing its negative impact on the overall performance of the matrix material has become a pressing issue in the field of PC / ABS alloy flame retardant modification technology. Summary of the Invention
[0006] The purpose of this invention is to provide a halogen-free flame-retardant PC / ABS alloy and its preparation method, so as to solve the problem of poor flame-retardant performance of PC / ABS alloy.
[0007] The objective of this invention can be achieved through the following technical solutions: The first aspect of this invention provides a halogen-free flame-retardant PC / ABS alloy, comprising PC resin and ABS resin, a flame retardant, a flame retardant synergist, and a processing aid; the mass ratio of the total mass of PC resin and ABS resin to the total mass of the flame retardant and the flame retardant synergist is 70-80:20-30; the flame retardant is APP@melamine-tannic acid-Fe; and the flame retardant synergist is DOPO-polyborosiloxane.
[0008] In some possible implementations, the amount of flame retardant synergist added is 8%–10% of the mass of the flame retardant.
[0009] In some possible implementations, the mass ratio of the PC resin to the ABS resin is 65-75:25-35.
[0010] In some possible implementations, the flame retardant is prepared by the following steps: Step S1: Dissolve melamine and tannic acid in anhydrous ethanol / water mixed solvent and stir at 40°C until completely dissolved; then slowly add FeCl3 solution dropwise, maintaining the pH at 4.5±0.3 with 10% acetic acid solution during the dropwise addition; after the dropwise addition is complete, continue stirring the reaction to obtain a melamine-tannic acid-Fe pre-dispersed solution. Step S2: Disperse APP in anhydrous ethanol / water mixed solvent, stir, and then ultrasonically disperse to obtain APP dispersion; Step S3: Slowly add the melamine-tannic acid-Fe pre-dispersed solution from step S1 to the APP dispersion from step S2, stir the reaction, and maintain the pH at 4.5–5.0 during the reaction. After the reaction is completed, the flame retardant (APP@melamine-tannic acid-Fe) is obtained.
[0011] The flame retardant is a core-shell structured ammonium polyphosphate@melamine-tannic acid-iron complex. Its shell structure is based on the following mechanism: the pyrogallol groups in tannic acid react with Fe... 3+ A stable metal-phenolic network complex is formed, with hydrogen bonds forming between the amino groups of melamine and the phenolic hydroxyl groups of tannic acid, while Fe... 3+ It can undergo weak coordination with the triazine ring nitrogen of melamine.
[0012] In some possible implementations, tannic acid and Fe³⁺ + The molar ratio is 1:2.5-3; The mass ratio of melamine, tannic acid and APP is 1.5:3-4:45; The mass fraction of APP in the APP dispersion is 30%–35%.
[0013] In some possible implementations, the flame retardant synergist is prepared through the following steps: Under nitrogen protection, boric acid and toluene were mixed and dispersed by stirring at room temperature to obtain a dispersion. DOPO silane coupling agent was dissolved in toluene and added to the above dispersion. The mixture was refluxed for 10-12 hours to obtain a flame retardant synergist (DOPO-polyborosiloxane).
[0014] The active hydroxyl groups at the end of the flame retardant synergist (DOPO-polyborosiloxane) can undergo transesterification with the carbonate bonds on the polycarbonate molecular chain, forming an interfacial micro-crosslinked structure bonded by Si-O covalent bonds. These crosslinking centers can induce shear deformation when the material is subjected to impact, thereby improving toughness by dissipating impact energy; at the same time, these crosslinking centers can also effectively reduce stress concentration and inhibit crack propagation through the "cavitation effect". Secondly, the DOPO groups introduced into the branched structure of DOPO-polyborosiloxane contain benzene rings, which can form π-π stacking interactions with the styrene component in the PC / ABS alloy and the aromatic structure in the flame retardant (APP@melamine-tannic acid-Fe), enabling it to act as a compatibilizer between the polymer matrix and the flame retardant, further improving interfacial bonding and reducing the negative impact of the flame retardant on mechanical properties.
[0015] In some possible implementations, the mass ratio of boric acid to DOPO silane coupling agent is 0.6-0.7 g: 4.5 g.
[0016] In some possible implementations, the additives account for 1%–1.5% of the total mass of the halogen-free flame-retardant PC / ABS alloy.
[0017] The processing aids include lubricants, dispersants, and antioxidants, with a mass ratio of 0.2:0.1:0.2.
[0018] A second aspect of this invention provides a method for preparing a halogen-free flame-retardant PC / ABS alloy, comprising the following steps: ABS resin, PC resin, flame retardant, flame retardant synergist and additives are mixed evenly; poured into a twin-screw extruder, extruded and granulated to prepare halogen-free flame-retardant PAC / ABS alloy.
[0019] In some possible implementations, the extrusion molding temperature range is 180-240°C.
[0020] The beneficial effects of this invention are: This invention provides a halogen-free flame-retardant PC / ABS alloy that combines highly efficient flame-retardant properties with excellent mechanical properties. It has significant engineering value and practical implications for expanding its application in high-end electronics, new energy vehicles, and other fields with stringent safety and reliability requirements. The halogen-free flame-retardant PC / ABS alloy of this invention contains a compounded flame retardant and a flame retardant synergist. Through synergistic action, these two agents significantly improve flame-retardant efficiency while ensuring good mechanical properties of the material.
[0021] In this process, the flame retardant coats ammonium polyphosphate through a melamine-tannic acid-iron complex formed by multiple interactions. On one hand, this organic-inorganic hybrid shell significantly improves the interfacial compatibility between ammonium polyphosphate and the polymer matrix, effectively promoting the uniform dispersion of the flame retardant in the PC / ABS alloy and reducing stress concentration caused by uneven dispersion, thereby mitigating the deterioration of the material's mechanical properties under high filler content. On the other hand, this shell itself constitutes a micro-intumescent flame retardant system, in which melamine serves as the gas source, tannic acid as the carbon source, and Fe... 3+ It plays a catalytic role in char formation and cross-linking, and during combustion, it can work synergistically with the core layer of ammonium polyphosphate to promote the formation of a denser and more stable expanded char layer.
[0022] The flame retardant synergist is DOPO-polyborosiloxane with a branched structure. During the melt blending process, this synergist exhibits multiple functions: during combustion, it can enhance the density and strength of the char layer, enabling it to withstand the impact of rapid airflow during combustion without collapsing or shrinking, thereby more effectively hindering the transfer of heat and oxygen and suppressing the release of smoke.
[0023] In summary, this invention, through the combined use of the flame retardant and flame retardant synergist, not only utilizes their respective functional group designs to form chemical bonds or physical entanglements with the PC / ABS alloy matrix, compensating for the loss of mechanical properties caused by the addition of the flame retardant, but also forms a stable and dense expanded carbon layer in the condensed phase, achieving dual flame retardancy in both the gas phase and the condensed phase. Thus, the halogen-free flame-retardant PC / ABS alloy achieves a simultaneous improvement in both flame retardant performance and mechanical properties. Detailed Implementation
[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0025] Obviously, the following description is merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.
[0026] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structure may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to enable those skilled in the art to fully understand this application and is not intended to limit the subject matter of the claims.
[0027] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions, and all technical features and optional technical features of this application can be combined to form new technical solutions.
[0028] The following is a detailed description of a halogen-free flame-retardant PC / ABS alloy and its preparation method according to an embodiment of this application.
[0029] In the following examples and comparative examples, the PC resin and ABS resin were kept the same and were all commercially available products. The PC resin (polycarbonate) had a melt index of 15-25 under test conditions of 300°C and 1.2 kg. The ABS resin was a polymer obtained by graft polymerization of butadiene, styrene, and acrylonitrile dissolved in an organic solvent, heated, and with the addition of an initiator and a molecular weight regulator. The butadiene rubber content of the ABS resin was 50%-70%.
[0030] The following is a detailed description with reference to specific examples.
[0031] Example 1
[0032] This embodiment provides a halogen-free flame-retardant PC / ABS alloy, and its preparation method includes the following steps: Step 1: Dry ABS resin, PC resin, flame retardant, flame retardant synergist, and additives under vacuum conditions at 80℃; the mass ratio of PC resin to ABS resin is 70:30; the mass ratio of the total mass of PC resin and ABS resin to the total mass of flame retardant and flame retardant synergist is 75:25; the amount of flame retardant synergist added is 10% of the mass of the flame retardant, and the additives account for 1% of the total mass of the halogen-free flame-retardant PC / ABS alloy; the flame retardant is APP@melamine-tannic acid-Fe; the flame retardant synergist is DOPO-polyborosiloxane; processing aids include lubricant, dispersant, and antioxidant. The mass ratio of lubricant, dispersant, and antioxidant is 0.2:0.1:0.2. The lubricant is pentaerythritol stearate; the dispersant is silicone oil; the antioxidant includes a primary antioxidant and a secondary antioxidant, the primary antioxidant is antioxidant 1010, and the secondary antioxidant is antioxidant 168, with a mass ratio of 1:1.
[0033] The second step involves mixing the weighed raw materials evenly in a high-speed mixer, pouring them into a twin-screw extruder, extruding and molding them, cooling and granulating them to prepare a halogen-free flame-retardant PAC / ABS alloy; the extrusion molding temperature range is 180-240℃.
[0034] The flame retardant is prepared through the following steps: Step S1: Dissolve 1.5g of melamine and 3.5g of tannic acid in 100mL of anhydrous ethanol / water mixed solvent (ethanol:water = 1:1, volume ratio), and stir at 40℃ until completely dissolved. Then, slowly add 0.5mol / L FeCl3 solution, maintaining the pH at 4.5±0.3 with 10% acetic acid solution during the addition. After the addition is complete, continue stirring at 40℃ for 1h to obtain a melamine-tannic acid-Fe pre-dispersed solution. Step S2: Disperse 45 g of APP (ammonium polyphosphate) in 200 mL of anhydrous ethanol / water mixed solvent (ethanol:water = 1:1, volume ratio), stir at 40°C for 15 min, and then sonicate for 10 min to obtain APP dispersion; Step S3: Slowly add the melamine-tannic acid-Fe pre-dispersed solution from Step S1 to the APP dispersion from Step S2, and stir at a constant temperature of 40°C for 2 hours, maintaining the pH at 4.5 during the reaction. After the reaction is complete, filter and wash three times each with deionized water and anhydrous ethanol to remove unreacted free melamine, tannic acid, and Fe. 3+ Vacuum dried at 60℃ for 24 hours, then ground through a 200-mesh sieve to obtain a flame retardant (APP@melamine-tannic acid-Fe); tannic acid: Fe³ + The molar ratio is 1:3.
[0035] The flame retardant synergist is prepared through the following steps: Under nitrogen protection, 15g of DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) and 20g of silane coupling agent KH-560 were added to a three-necked flask equipped with a mechanical stirrer, a reflux condenser, and a nitrogen inlet tube. The bottom of the flask was immersed in an oil bath with a DF-101S thermostatic magnetic stirrer. Nitrogen purging was turned on to ensure that the reaction system was in a nitrogen atmosphere. The temperature was raised to 140℃ and the reaction was carried out for 6 hours to obtain DOPO silane coupling agent. Under nitrogen protection, 0.65 g of boric acid and 30 mL of toluene were mixed and stirred at room temperature for 10 min to obtain a dispersion. 4.5 g of DOPO silane coupling agent was dissolved in 40 mL of toluene and added to the above dispersion. The mixture was heated to 110 °C and refluxed for 10 h. Methanol generated during the reaction was continuously removed using a water separator. After the reaction was completed, the mixture was cooled to room temperature, and the solvent was removed from the filtrate by rotary evaporation. The filtrate was then dried in a vacuum oven at 80 °C for 6 h to obtain the flame retardant synergist (DOPO-polyborosiloxane).
[0036] Example 2
[0037] The difference between this embodiment and Example 1 is that the mass ratio of PC resin to ABS resin is 65:35, while the remaining raw materials and preparation process are the same as in Example 1.
[0038] This embodiment provides a halogen-free flame-retardant PC / ABS alloy, and its preparation method includes the following steps: Step 1: Dry ABS resin, PC resin, flame retardant, flame retardant synergist, and additives under vacuum conditions at 80℃; the mass ratio of PC resin to ABS resin is 65:35; the mass ratio of the total mass of PC resin and ABS resin to the total mass of flame retardant and flame retardant synergist is 75:25; the amount of flame retardant synergist added is 10% of the mass of the flame retardant, and the additives account for 1% of the total mass of the halogen-free flame-retardant PC / ABS alloy; the flame retardant is APP@melamine-tannic acid-Fe; the flame retardant synergist is DOPO-polyborosiloxane; the processing aids are the same as in Example 1; the flame retardant is the same as in Example 1; the flame retardant synergist is the same as in Example 1.
[0039] The second step involves mixing the weighed raw materials evenly in a high-speed mixer, pouring them into a twin-screw extruder, extruding and molding them, cooling and granulating them to prepare a halogen-free flame-retardant PAC / ABS alloy; the extrusion molding temperature range is 180-240℃.
[0040] Example 3
[0041] The difference between this embodiment and Example 1 is that the mass ratio of PC resin to ABS resin is 75:25, while the remaining raw materials and preparation process are the same as in Example 1.
[0042] This embodiment provides a halogen-free flame-retardant PC / ABS alloy, and its preparation method includes the following steps: Step 1: Dry ABS resin, PC resin, flame retardant, flame retardant synergist, and additives under vacuum conditions at 80℃; the mass ratio of PC resin to ABS resin is 75:25; the mass ratio of the total mass of PC resin and ABS resin to the total mass of flame retardant and flame retardant synergist is 75:25; the amount of flame retardant synergist added is 10% of the mass of the flame retardant; the additives account for 1% of the total mass of the halogen-free flame-retardant PC / ABS alloy; the flame retardant is APP@melamine-tannic acid-Fe; the flame retardant synergist is DOPO-polyborosiloxane; the processing aids are the same as in Example 1. The flame retardant synergist is the same as in Example 1.
[0043] The second step involves mixing the weighed raw materials evenly in a high-speed mixer, pouring them into a twin-screw extruder, extruding and molding them, cooling and granulating them to prepare a halogen-free flame-retardant PAC / ABS alloy; the extrusion molding temperature range is 180-240℃.
[0044] Example 4
[0045] The difference between this embodiment and Example 1 is that the mass ratio of the total mass of PC resin and ABS resin to the total mass of flame retardant and flame retardant synergist is 80:20, while the remaining raw materials and preparation process are the same as in Example 1.
[0046] The preparation method includes the following steps: Step 1: Dry ABS resin, PC resin, flame retardant, flame retardant synergist, and additives under vacuum conditions at 80℃; the mass ratio of PC resin to ABS resin is 70:30; the mass ratio of the total mass of PC resin and ABS resin to the total mass of flame retardant and flame retardant synergist is 80:20; the amount of flame retardant synergist added is 8%-10% of the mass of the flame retardant, and the additives account for 1% of the total mass of the halogen-free flame-retardant PC / ABS alloy; the flame retardant is APP@melamine-tannic acid-Fe; the flame retardant synergist is DOPO-polyborosiloxane; the processing aids are the same as in Example 1. The flame retardant and flame retardant synergist are the same as in Example 1.
[0047] The second step involves mixing the weighed raw materials evenly in a high-speed mixer, pouring them into a twin-screw extruder, extruding and molding them, cooling and granulating them to prepare a halogen-free flame-retardant PAC / ABS alloy; the extrusion molding temperature range is 180-240℃.
[0048] Example 5
[0049] The difference between this embodiment and Example 1 is that the mass ratio of the total mass of PC resin and ABS resin to the total mass of flame retardant and flame retardant synergist is 70:30, while the remaining raw materials and preparation process remain the same as in Example 1.
[0050] The preparation method includes the following steps: Step 1: Dry ABS resin, PC resin, flame retardant, flame retardant synergist, and additives under vacuum conditions at 80℃; the mass ratio of PC resin to ABS resin is 70:30; the mass ratio of the total mass of PC resin and ABS resin to the total mass of flame retardant and flame retardant synergist is 70:30; the amount of flame retardant synergist added is 10% of the mass of the flame retardant; the additives account for 1% of the total mass of the halogen-free flame-retardant PC / ABS alloy; the flame retardant is APP@melamine-tannic acid-Fe; the flame retardant synergist is DOPO-polyborosiloxane; the processing aids are the same as in Example 1. The flame retardant and flame retardant synergist are the same as in Example 1.
[0051] The second step involves mixing the weighed raw materials evenly in a high-speed mixer, pouring them into a twin-screw extruder, extruding and molding them, cooling and granulating them to prepare a halogen-free flame-retardant PAC / ABS alloy; the extrusion molding temperature range is 180-240℃.
[0052] Example 6
[0053] The difference between this embodiment and Example 1 is that the amount of flame retardant synergist added is 8% of the mass of the flame retardant, while the remaining raw materials and preparation process are the same as in Example 1.
[0054] The preparation method includes the following steps: Step 1: Dry ABS resin, PC resin, flame retardant, flame retardant synergist, and additives under vacuum conditions at 80℃; the mass ratio of PC resin to ABS resin is 70:30; the mass ratio of the total mass of PC resin and ABS resin to the total mass of flame retardant and flame retardant synergist is 75:25; the amount of flame retardant synergist added is 8% of the mass of the flame retardant, and the additives account for 1% of the total mass of the halogen-free flame-retardant PC / ABS alloy; the flame retardant is APP@melamine-tannic acid-Fe; the flame retardant synergist is DOPO-polyborosiloxane; the processing aids are the same as in Example 1. The flame retardant and flame retardant synergist are the same as in Example 1.
[0055] The second step involves mixing the weighed raw materials evenly in a high-speed mixer, pouring them into a twin-screw extruder, extruding and molding them, cooling and granulating them to prepare a halogen-free flame-retardant PAC / ABS alloy; the extrusion molding temperature range is 180-240℃.
[0056] Example 7
[0057] The difference between this embodiment and Example 1 is that the amount of flame retardant synergist added is 9% of the mass of the flame retardant, while the remaining raw materials and preparation process are the same as in Example 1.
[0058] The preparation method includes the following steps: Step 1: Dry ABS resin, PC resin, flame retardant, flame retardant synergist, and additives under vacuum conditions at 80℃; the mass ratio of PC resin to ABS resin is 70:30; the mass ratio of the total mass of PC resin and ABS resin to the total mass of flame retardant and flame retardant synergist is 75:25; the amount of flame retardant synergist added is 9% of the mass of the flame retardant, and the additives account for 1% of the total mass of the halogen-free flame-retardant PC / ABS alloy; the flame retardant is APP@melamine-tannic acid-Fe; the flame retardant synergist is DOPO-polyborosiloxane; the processing aids are the same as in Example 1. The flame retardant and flame retardant synergist are the same as in Example 1.
[0059] The second step involves mixing the weighed raw materials evenly in a high-speed mixer, pouring them into a twin-screw extruder, extruding and molding them, cooling and granulating them to prepare a halogen-free flame-retardant PAC / ABS alloy; the extrusion molding temperature range is 180-240℃.
[0060] Example 8
[0061] The difference between this embodiment and Example 1 is that the additives account for 1.5% of the total mass of the halogen-free flame-retardant PC / ABS alloy, while the remaining raw materials and preparation process remain the same as in Example 1.
[0062] The preparation method includes the following steps: Step 1: Dry ABS resin, PC resin, flame retardant, flame retardant synergist, and additives under vacuum conditions at 80℃; the mass ratio of PC resin to ABS resin is 70:30; the mass ratio of the total mass of PC resin and ABS resin to the total mass of flame retardant and flame retardant synergist is 75:25; the amount of flame retardant synergist added is 10% of the mass of the flame retardant, and the additives account for 1.5% of the total mass of the halogen-free flame-retardant PC / ABS alloy; the flame retardant is APP@melamine-tannic acid-Fe; the flame retardant synergist is DOPO-polyborosiloxane; the processing aids are the same as in Example 1. The flame retardant and flame retardant synergist are the same as in Example 1.
[0063] The second step involves mixing the weighed raw materials evenly in a high-speed mixer, pouring them into a twin-screw extruder, extruding and molding them, cooling and granulating them to prepare a halogen-free flame-retardant PAC / ABS alloy; the extrusion molding temperature range is 180-240℃.
[0064] Example 9
[0065] The difference between this embodiment and Example 1 is that the preparation process of the flame retardant synergist is different, while the other raw materials and preparation process remain the same as in Example 1. The flame retardant synergist is prepared through the following steps: Under nitrogen protection, 15g of DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) and 20g of silane coupling agent KH-560 were added to a three-necked flask equipped with a mechanical stirrer, a reflux condenser, and a nitrogen inlet tube. The bottom of the flask was immersed in an oil bath with a DF-101S thermostatic magnetic stirrer. Nitrogen purging was turned on to ensure that the reaction system was in a nitrogen atmosphere. The temperature was raised to 150℃ and the reaction was carried out for 7 hours to obtain DOPO silane coupling agent. Under nitrogen protection, 0.7 g boric acid and 30 mL toluene were mixed and stirred at room temperature for 20 min to obtain a dispersion. 4.5 g DOPO silane coupling agent was dissolved in 40 mL toluene and added to the above dispersion. The mixture was heated to 110 °C and refluxed for 12 h. Methanol generated during the reaction was continuously removed using a water separator. After the reaction was completed, the mixture was cooled to room temperature, and the solvent was removed by rotary evaporation of the filtrate. The filtrate was then dried in a vacuum oven at 80 °C for 6 h to obtain the flame retardant synergist (DOPO-polyborosiloxane).
[0066] Example 10
[0067] The difference between this embodiment and Example 1 is that the preparation process of the flame retardant is different, while the other raw materials and preparation process remain the same as in Example 1. The flame retardant is prepared through the following steps: Step S1: Dissolve 1.5g of melamine and 4g of tannic acid in 100mL of anhydrous ethanol / water mixed solvent (ethanol:water = 1:1, volume ratio), and stir at 40℃ until completely dissolved. Then, slowly add 0.5mol / L FeCl3 solution, maintaining the pH at 4.5±0.3 with 10% acetic acid solution during the addition. After the addition is complete, continue stirring at 40℃ for 1h to obtain a melamine-tannic acid-Fe pre-dispersed solution. Step S2: Disperse 45 g of APP (ammonium polyphosphate) in 200 mL of anhydrous ethanol / water mixed solvent (ethanol:water = 1:1, volume ratio), stir at 40°C for 15 min, and then sonicate for 10 min to obtain APP dispersion; Step S3: Slowly add the melamine-tannic acid-Fe pre-dispersed solution from Step S1 to the APP dispersion from Step S2, and stir at a constant temperature of 40°C for 3 hours, maintaining the pH at 5.0 during the reaction. After the reaction is complete, filter and wash three times each with deionized water and anhydrous ethanol to remove unreacted free melamine, tannic acid, and Fe. 3+ Vacuum dried at 60℃ for 24 hours, then ground through a 200-mesh sieve to obtain a flame retardant (APP@melamine-tannic acid-Fe); tannic acid: Fe³ + The molar ratio is 1:3.
[0068] Comparative Example 1
[0069] Compared with Example 1, this comparative example does not add flame retardant synergists; the amount of flame retardant synergists is made up with flame retardants. The remaining raw materials and preparation process are the same as in Example 1.
[0070] Comparative Example 2
[0071] Compared with Example 1, the flame retardant synergist in this comparative example is different. Specifically, the DOPO silane coupling agent was replaced with silane coupling agent KH-560 in the preparation process of the flame retardant synergist, while the other raw materials and preparation process remained the same as in Example 1.
[0072] Comparative Example 3
[0073] Compared with Example 1, the flame retardant in this comparative example is replaced with ammonium polyphosphate, and the flame retardant synergist is replaced with the one prepared in Comparative Example 2. The other raw materials and preparation process are the same as in Example 1.
[0074] Comparative Example 4
[0075] Compared with Example 1, this comparative example replaces the flame retardant and flame retardant synergist with ammonium polyphosphate, while the remaining raw materials and preparation process remain the same as in Example 1.
[0076] Test case
[0077] Performance tests were conducted on Examples 1-10 and Comparative Examples 1-4. The prepared halogen-free flame-retardant PAC / ABS alloys were injection molded at 230-240°C to prepare test samples for the following performance tests: Limiting Oxygen Index (LOI) Test: The LOI test was performed according to ASTM D2863. A sample measuring 100 mm × 6.5 mm × 3 mm was vertically fixed onto a transparent test column. A mixture of oxygen and nitrogen was introduced into the column, and the upper part of the sample was ignited. The subsequent combustion behavior and combustion cycle were observed, and the minimum oxygen concentration sufficient to sustain combustion was recorded. The test was performed six times, and the average value was taken.
[0078] UL-94 Vertical Burning Test: The UL-94 test is conducted according to ASTM D3801 standard, using a 100 mm × 13 mm × 3 mm sample to perform a vertical burning test on a horizontal-vertical burner. Six tests are performed, and the average value is taken.
[0079] Mechanical property testing
[0080] The tensile strength and elongation at break of the test specimens were tested using an electronic universal testing machine in accordance with the standard (GB / T1040.3-2006), and the notched impact test was performed in accordance with the standard GB / T 1843-2008.
[0081] The results are shown in Table 1: Table 1
[0082] As shown in Table 1, the halogen-free flame-retardant PC / ABS alloy provided by this invention achieves simultaneous improvement in flame retardant performance and mechanical properties through the synergistic effect of the flame retardant (APP@melamine-tannic acid-Fe) and the flame retardant synergist (DOPO-polyborosiloxane). According to Examples 1-3, increasing the PC ratio improves flame retardancy and rigidity, but decreases toughness; the PC ratio is optimal in Example 1. Comparison between Example 1 and Comparative Examples 1-3 shows that the DOPO groups in the flame retardant synergist improve interfacial compatibility through π-π stacking and contribute to gas-phase flame retardancy; the flame retardant synergist forms a micro-crosslinked structure through transesterification, compensating for mechanical losses. Systems without the DOPO synergist or without treated APP show significant deterioration in both flame retardant and mechanical properties. The APP treatment in this invention effectively improves its dispersibility and further enhances interfacial bonding. This invention achieves a balance between high-efficiency flame retardancy and good mechanical properties in the halogen-free flame-retardant PC / ABS alloy through multiple synergistic mechanisms.
[0083] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0084] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A halogen-free flame-retardant PC / ABS alloy, characterized in that, It includes PC resin and ABS resin, flame retardant, flame retardant synergist and processing aid; the mass ratio of the total mass of PC resin and ABS resin to the total mass of flame retardant and flame retardant synergist is 70-80:20-30; the flame retardant is APP@melamine-tannic acid-Fe; the flame retardant synergist is DOPO-polyborosiloxane.
2. The halogen-free flame-retardant PC / ABS alloy according to claim 1, characterized in that, The amount of flame retardant synergist added is 8%-10% of the mass of the flame retardant.
3. The halogen-free flame-retardant PC / ABS alloy according to claim 1, characterized in that, The mass ratio of PC resin to ABS resin is 65-75:25-35.
4. The halogen-free flame-retardant PC / ABS alloy according to claim 1, characterized in that, The flame retardant is prepared by the following steps: Step S1: Dissolve melamine and tannic acid in anhydrous ethanol / water mixed solvent and stir at 40°C until completely dissolved; then slowly add FeCl3 solution dropwise, maintaining the pH at 4.5±0.3 with 10% acetic acid solution during the dropwise addition; after the dropwise addition is complete, continue stirring the reaction to obtain a melamine-tannic acid-Fe pre-dispersed solution. Step S2: Disperse APP in anhydrous ethanol / water mixed solvent, stir, and then ultrasonically disperse to obtain APP dispersion; Step S3: Slowly add the melamine-tannic acid-Fe pre-dispersed solution from step S1 to the APP dispersion from step S2, stir the reaction, and maintain the pH at 4.5–5.0 during the reaction. After the reaction is completed, the flame retardant is obtained.
5. The halogen-free flame-retardant PC / ABS alloy according to claim 1, characterized in that, Tannic acid and Fe³ + The molar ratio is 1:2.5-3; The mass ratio of melamine, tannic acid and APP is 1.5:3-4:45; The mass fraction of APP in the APP dispersion is 30%–35%.
6. The halogen-free flame-retardant PC / ABS alloy according to claim 1, characterized in that, Flame retardant synergists are prepared through the following steps: Under nitrogen protection, boric acid and toluene were mixed and dispersed by stirring at room temperature to obtain a dispersion. DOPO silane coupling agent was dissolved in toluene and added to the above dispersion. The mixture was refluxed for 10-12 hours to obtain a flame retardant synergist.
7. The halogen-free flame-retardant PC / ABS alloy according to claim 1, characterized in that, The mass ratio of boric acid to DOPO silane coupling agent is 0.6-0.7g:4.5g.
8. The halogen-free flame-retardant PC / ABS alloy according to claim 1, characterized in that, The additives account for 1%–1.5% of the total mass of the halogen-free flame-retardant PC / ABS alloy; The processing aids include lubricants, dispersants, and antioxidants, with a mass ratio of 0.2:0.1:0.
2.
9. A method for preparing a halogen-free flame-retardant PC / ABS alloy, used to prepare the halogen-free flame-retardant PC / ABS alloy according to any one of claims 1-8, characterized in that, Includes the following steps: ABS resin, PC resin, flame retardant, flame retardant synergist and additives are mixed evenly, poured into a twin-screw extruder, extruded and granulated to prepare halogen-free flame-retardant PAC / ABS alloy.
10. The method for preparing a halogen-free flame-retardant PC / ABS alloy according to claim 9, characterized in that, The extrusion molding temperature range is 180-240℃.