High-flame-retardant easy-to-color recycled ABS composite material and preparation method thereof

Abstract

The application relates to a high-flame-retardant easy-to-color recycled ABS composite material and a preparation method thereof, and belongs to the technical field of recycled ABS materials, and comprises the following components: 70-85% of ABS recycled material, 6-15% of aluminum diethyl phosphinate, 5-8% of melamine pyrophosphate, 1.5-3% of silane-modified zinc borate and 2.5-4% of methyl methacrylate-butadiene-styrene copolymer. The recycled ABS composite material prepared by the application realizes the unification of V-0 grade flame retardation and excellent coloring performance of high-content recycled ABS, and meanwhile, the mechanical properties are ensured.

Description

Technical Field

[0001] This application relates to the field of recycled ABS material technology, and in particular to a highly flame-retardant and easily colored recycled ABS composite material and its preparation method. Background Technology

[0002] Recycled ABS plastic is widely available and inexpensive, effectively enabling resource recycling and showing broad application prospects in fields such as electronic appliance housings, automotive interiors, office equipment, and household goods. However, after repeated heat processing and recycling, recycled ABS undergoes molecular chain breakage, a decrease in molecular weight, an increase in double bond content, and a significant deterioration in thermal stability and mechanical properties. Its flammability also declines considerably, making it difficult to meet the flame-retardant requirements of products. Currently, flame-retardant modification of recycled ABS mainly employs halogen-based flame retardants, conventional phosphorus-nitrogen flame retardants, or inorganic flame-retardant systems. However, all of these systems have the following significant drawbacks: Halogen-based flame retardants, when combined with antimony trioxide, offer high flame-retardant efficiency but suffer from poor coloring performance, are prone to yellowing and precipitation, and face significant environmental pressure, contradicting the current trend of halogen-free and environmentally friendly development; conventional phosphorus-nitrogen flame retardant systems require high addition levels to achieve V-0 flame retardancy, leading not only to a significant decrease in the mechanical properties of recycled ABS but also to problems such as graying and uneven coloring; inorganic flame retardants require extremely high addition levels, have poor compatibility, and low surface gloss, further deteriorating coloring performance.

[0003] In existing technologies, flame retardant modification of ABS is generally aimed at new ABS or low-content recycled ABS, without involving high-content recycled ABS. Furthermore, conventional compounding only focuses on flame retardant performance and cannot take into account coloring performance. As a result, there are common problems such as yellowing, graying, and color difference after flame retardant treatment, making it difficult to use for the production of appearance parts. Summary of the Invention

[0004] The purpose of this application is to address the shortcomings of existing technologies where high-content recycled ABS cannot simultaneously achieve both flame retardancy and colorability, and to propose a highly flame-retardant and easily colorable recycled ABS composite material and its preparation method. This application achieves a balance between V-0 flame retardancy and excellent colorability in high-content recycled ABS by optimizing the flame-retardant system and the dispersion synergistic system, while simultaneously ensuring mechanical properties.

[0005] In the first aspect, the high flame retardant and easily colorable recycled ABS composite material provided in this application adopts the following technical solution: based on the total mass of the raw material components of the recycled ABS composite material as 100%, it includes: 70~85% recycled ABS material, 6~15% aluminum diethylphosphinate (ADP), 5~8% melamine pyrophosphate (MPP), 1.5~3% silane-modified zinc borate and 2.5~4% methyl methacrylate-butadiene-styrene copolymer (MBS).

[0006] Through the above technical solutions, when the content of recycled ABS is above 70%, the resource advantages of recycled materials can be maximized and costs reduced, while ensuring the basic mechanical properties of the substrate. When the content of recycled ABS is below 85%, the flame retardancy standard can be avoided due to an excessively high substrate content. The content range of aluminum diethylphosphinate is suitable for systems with high recycled ABS content, and it can still play a highly efficient flame retardant role at low addition levels, balancing cost and performance. The content range of melamine pyrophosphate matches that of ADP, adapting to the flame retardant synergistic requirements of systems with a high substrate content, ensuring that V-0 flame retardancy is still achieved even with an increased substrate content. Silane Modified zinc borate, as a flame retardant aid, can improve dispersibility within a specific particle size range. Silane modification enhances compatibility with ABS substrates and plays a role in suppressing smoke and dripping during combustion. This application utilizes ADP-MPP-silane modified zinc borate to form a phosphorus-nitrogen-zinc ternary flame retardant synergy, achieving high-efficiency flame retardancy with low addition amounts, suitable for the high content requirements of 70.0~85.0% recycled ABS materials. Methyl methacrylate-butadiene-styrene copolymer forms a dispersion-stabilization-toughening synergy with this flame retardant system, solving the problems of molecular chain defects and easy degradation in high-content recycled ABS, as well as the problems of inorganic flame retardant agglomeration and poor coloring after flame retardation.

[0007] Optionally, the preparation method of the silane-modified zinc borate includes the following steps: (1) Add zinc borate powder to deionized water and ultrasonically disperse for 30-40 min to form a dispersion system. Then add dispersant to the dispersion system, adjust the pH to 8.0-9.0, and stir at 60-70 °C for 1-1.5 h to obtain zinc borate dispersion. (2) Add γ-aminopropyltriethoxysilane dropwise to the zinc borate dispersion. After the addition is complete, raise the temperature to 80~85 ℃ and keep it at a constant temperature for 2~3 h. After the heat preservation is completed, cool it down, and then centrifuge, wash and vacuum dry in sequence to obtain silane-modified zinc borate.

[0008] Through the above technical solution, in the preparation of silane-modified zinc borate, this application first ensures the activation of hydroxyl groups at a pH of 8.0~9.0, and ensures the complete condensation reaction at a high temperature of 80~85 ℃, so that silane and zinc borate form stable Si-O-Zn covalent bonds. By precisely controlling the amount of silane added and the reaction conditions, the release of the modifier is avoided. This application prepares silane-modified zinc borate through a two-step modification method. The synergistic flame retardant effect of silane-modified zinc borate with ADP and MPP is better, which is suitable for the flame retardant and coloring requirements of high recycled ABS content systems.

[0009] Optionally, the mass ratio of the zinc borate powder, deionized water, dispersant, and γ-aminopropyltriethoxysilane is 100:400~500:1~2:3~5.

[0010] Through the above technical solution, in the pretreatment stage (60~70 ℃, pH 8.0~9.0), sufficient deionized water and an appropriate amount of dispersant can be used to fully activate the hydroxyl groups on the surface of zinc borate. In the modification reaction stage (80~85 ℃), a certain amount of γ-aminopropyltriethoxysilane can completely coat the surface of zinc borate. The resulting silane-modified zinc borate can form a highly efficient flame retardant synergy with ADP and MPP, and at the same time, it can synergistically improve the dispersibility with methyl methacrylate-butadiene-styrene copolymer, ensuring that the recycled ABS composite material achieves UL94 V-0 flame retardancy and coloring grade 5 (no yellowing or graying).

[0011] Optionally, the zinc borate powder has a particle size of 3-5 µm.

[0012] Through the above technical solution, zinc borate powder with a size of 3~5 μm, after being modified with silane by the two-step method of the present invention, exhibits excellent dispersibility and will not form visible particles due to agglomeration. This effectively avoids the problems of graying and uneven coloring caused by zinc borate agglomeration.

[0013] Further optionally, the dispersant is sodium dodecylbenzenesulfonate and / or polyethylene glycol.

[0014] Through the above technical solution, the molecular structure of sodium dodecylbenzenesulfonate contains a hydrophilic group (-SO3⁻) and a hydrophobic long carbon chain (C). 12 H 25 - The hydrophilic groups can tightly bind to the weakly positively charged zinc borate surface through electrostatic adsorption and hydrogen bonding, while the hydrophobic long carbon chains extend into the aqueous phase, significantly reducing the surface energy and van der Waals forces of the zinc borate particles, thus inhibiting particle aggregation at its source. Polyethylene glycol contains a large number of ether bonds (-COC-) hydrophilic groups, which can be adsorbed onto the zinc borate surface through hydrogen bonding to form a dense polymer hydration film. This film prevents particle aggregation through steric hindrance, thereby significantly improving the compatibility of silane-modified zinc borate with recycled ABS and methyl methacrylate-butadiene-styrene copolymer, preventing zinc borate from re-aggregating in the matrix, and significantly improving the coloring properties of ABS composites.

[0015] Optionally, the melt flow index of the recycled ABS material at 220 ℃ / 10 kg is 15~18 mL / 10 min, and the test standard is ISO 1133-1-2011; the impact strength of the recycled ABS material at the test standard is 8~10 KJ / m². 2 .

[0016] Optionally, the raw material components of the recycled ABS composite material further include 0.3-0.5% antioxidant and 0.3-0.5% lubricant.

[0017] Further optionally, the antioxidant is a mixture of antioxidant 1098 and antioxidant 168 in a mass ratio of 1:1.

[0018] Through the above technical solution, antioxidant 1098 has a large steric hindrance, which can quickly terminate the free radical chain reaction generated during the processing and use of high-content recycled ABS, inhibiting further breakage of molecular chains from the source, and avoiding yellowing during processing and long-term aging and embrittlement; selecting a mixture of antioxidant 1098 and antioxidant 168 with a mass ratio of 1:1 as the antioxidant of this application can effectively prevent the antioxidant from being released into the ABS composite material, thereby affecting the appearance and color of the ABS composite material.

[0019] Further optionally, the lubricant is pentaerythritol stearate.

[0020] Through the above technical solution, the molecular chain of pentaerythritol stearate can coat the surface of ADP, MPP, and silane-modified zinc borate powders, forming a "dispersion-lubrication" synergy with methyl methacrylate-butadiene-styrene copolymer and dispersants (sodium dodecylbenzenesulfonate and / or polyethylene glycol), reducing the agglomeration of inorganic powders and avoiding problems such as fluctuations in flame retardant performance and graying caused by agglomeration.

[0021] Secondly, this application provides a method for preparing the high flame retardant and easily colorable recycled ABS composite material described above, the preparation method comprising the following steps: S1. The ABS recycled material, aluminum diethylphosphinate, melamine pyrophosphate, silane-modified zinc borate, and methyl methacrylate-butadiene-styrene copolymer are mixed in a mass percentage ratio to obtain a uniform mixture. S3. Add the mixture to a twin-screw extruder and sequentially perform melt blending, extrusion, water cooling, pelletizing, and drying to obtain the high flame retardant and easily colorable recycled ABS composite material. The temperature of each section of the twin-screw extruder is 175~205 ℃, and the main machine speed is 280~350 r / min.

[0022] In summary, this application includes at least one of the following beneficial technical effects: 1. This application uses high-content recycled ABS material in combination with a certain amount of ADP, MPP, silane-modified zinc borate and methyl methacrylate-butadiene-styrene copolymer. ADP-MPP-silane-modified zinc borate synergistically form a phosphorus-nitrogen-zinc ternary flame retardant system, which can achieve high-efficiency flame retardancy with low addition amount, and is suitable for the high content requirement of 70.0~85.0% recycled ABS material. The methyl methacrylate-butadiene-styrene copolymer and the phosphorus-nitrogen-zinc ternary flame retardant system form a dispersion-stabilization-toughening synergy, which solves the problems of molecular chain defects and easy degradation of high-content recycled ABS, as well as the problems of inorganic flame retardant agglomeration and poor coloring after flame retardation, while maintaining the mechanical properties of recycled ABS. 2. In a preferred embodiment, silane-modified zinc borate is used as a flame retardant. After the 3-5 μm zinc borate powder is modified by the two-step silane modification method of this invention, it exhibits excellent dispersibility. The silane modification enhances its compatibility with the ABS substrate, suppressing smoke and dripping during combustion. Simultaneously, it catalyzes the refinement of the char layer, improves the density of the char layer, and prevents char layer cracking. Furthermore, the two-step modification method further improves dispersibility and compatibility, preventing agglomeration and ash formation, significantly optimizing coloring performance. It also exhibits better synergistic flame retardant effects with ADP and MPP, making it suitable for the flame retardant and coloring requirements of high recycled ABS content systems. 3. The raw materials for the overall formula of this application are simple and readily available, and the preparation efficiency is high. It is suitable for large-scale industrial production, which greatly improves the recycling value of waste ABS materials and significantly reduces the cost of preparing ABS materials. Detailed Implementation

[0023] The present application will be further described in detail below with reference to specific embodiments.

[0024] The following examples further illustrate the highly flame-retardant and easily colorable recycled ABS composite material and its preparation method described in this application. The examples are implemented based on the technical solution of this application, providing detailed implementation methods and specific operating procedures; however, the scope of protection of this application is not limited to the following examples.

[0025] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0026] ABS recycled material: Purchased from Qingdao Hailuyuan Recycling Technology Co., Ltd., model ABSSR101R, with a melt flow index (test method ISO 1133-1-2011, test conditions 220 ℃ / 10 kg) of 16.81 g10 min and an impact strength (test method ISO 179-2) of 8.66 KJ / m. 2The tensile strength (test method ISO 527) is 35.82 MPa, the tensile breaking rate (test method ISO 527) is 43.38%, the flexural strength (test method ISO 178) is 59.08 MPa, and the flexural modulus (test method ISO 178) is 2131.25 MPa. Aluminum diethylphosphinate (ADP): Model ADP-33, purchased from Qingdao Ouprui New Materials Co., Ltd.; Melamine pyrophosphate (MPP): Purchased from Qingdao Oprui New Materials Co., Ltd.; Zinc borate powder: purchased from Shandong Jinyingtai Chemical Co., Ltd., with an average particle size of 3~5 µm; γ-aminopropyltriethoxysilane (KH-550): purity ≥98%, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Methyl methacrylate-butadiene-styrene copolymer (MBS): purchased from Shanghai Better Chemical Co., Ltd. Sodium dodecylbenzenesulfonate (SDBS): analytical grade, purchased from Sinopharm Chemical Reagent Co., Ltd. Polyethylene glycol (PEG-400): analytical grade, purchased from Sinopharm Chemical Reagent Co., Ltd.; Antioxidant 1098: Purchased from BASF (China) Co., Ltd.; Antioxidant 168: Purchased from BASF (China) Co., Ltd.

[0027] Preparation Example 1 A method for preparing silane-modified zinc borate includes the following steps: (1) Weigh 100 g of zinc borate powder and add it to 400 g of deionized water. Disperse it ultrasonically for 30 min under an ultrasonic power of 300 W to form a dispersion system. Then add 1 g of sodium dodecylbenzenesulfonate (dispersant) to the dispersion system, adjust the pH to 8.0 with ammonia water, and stir at 500 r / min for 1 h at 60 °C to obtain zinc borate dispersion. (2) 3 g of γ-aminopropyltriethoxysilane was added dropwise to the zinc borate dispersion at a rate of 1 mL / min. After the addition was completed, the temperature was raised to 80 °C and stirred at a constant temperature for 2 h for heat preservation. After the heat preservation was completed, the mixture was naturally cooled to room temperature (25 °C). Then, it was centrifuged at 8000 r / min for 10 min, washed 3 times each with deionized water and anhydrous ethanol, and finally dried under vacuum at 80 °C for 12 h to obtain silane-modified zinc borate, denoted as SZB-1. The mass ratio of zinc borate powder, deionized water, dispersant, and γ-aminopropyltriethoxysilane is 100:400:1:3.

[0028] Preparation Example 2 A method for preparing silane-modified zinc borate includes the following steps: (1) Weigh 100 g of zinc borate powder and add it to 450 g of deionized water. Disperse the powder under ultrasonic power of 350 W for 35 min to form a dispersion system. Then add 1.5 g of polyethylene glycol (dispersant) to the dispersion system, adjust the pH to 8.5 with ammonia water, and stir at 550 r / min for 1.2 h at 65 °C to obtain zinc borate dispersion. (2) Add 4 g of γ-aminopropyltriethoxysilane dropwise to the zinc borate dispersion at a rate of 0.8 mL / min. After the addition is completed, raise the temperature to 83 °C and keep it at a constant temperature for 2.5 h. After the heat preservation is completed, let it cool naturally to room temperature (25 °C). Then centrifuge at 8000 r / min for 10 min, wash with deionized water and anhydrous ethanol 3 times each, and finally vacuum dry at 80 °C for 12 h to obtain silane-modified zinc borate, denoted as SZB-2. The mass ratio of zinc borate powder, deionized water, dispersant, and γ-aminopropyltriethoxysilane is 100:450:1.5:4.

[0029] Preparation Example 3 A method for preparing silane-modified zinc borate includes the following steps: (1) Weigh 100 g of zinc borate powder and add it to 500 g of deionized water. Disperse it ultrasonically for 40 min under an ultrasonic power of 400 W to form a dispersion system. Then add a mixture of 1 g sodium dodecylbenzenesulfonate and 1 g polyethylene glycol as a dispersant to the dispersion system. Adjust the pH to 9.0 with ammonia water and stir at 600 r / min at 70 °C for 1.5 h to obtain zinc borate dispersion. (2) 5 g of γ-aminopropyltriethoxysilane was added dropwise to the zinc borate dispersion at a rate of 0.6 mL / min. After the addition was completed, the temperature was raised to 85 °C and kept at a constant temperature for 3 h. After the temperature was kept at a constant temperature, the mixture was naturally cooled to room temperature. Then, it was centrifuged at 8000 r / min for 10 min, washed 3 times each with deionized water and anhydrous ethanol, and finally dried under vacuum at 80 °C for 12 h to obtain silane-modified zinc borate, denoted as SZB-3. The mass ratio of zinc borate powder, deionized water, dispersant, and γ-aminopropyltriethoxysilane is 100:500:2:5.

[0030] Example 1 A highly flame-retardant and easily colorable recycled ABS composite material is prepared by the following steps: S1. Weigh the following raw material components according to the following mass percentages: 85% recycled ABS, 6% aluminum diethylphosphinate (ADP), 5% melamine pyrophosphate (MPP), 1.5% silane-modified zinc borate (SZB-2), and 2.5% methyl methacrylate-butadiene-styrene copolymer (MBS). Add the above components to a high-speed mixer and mix at 800 r / min for 5 min to obtain a homogeneous mixture. S2. The homogeneous mixture is added to a twin-screw extruder. The temperatures of each section of the twin-screw extruder from the feeding section to the die head are set as follows: Zone 1 175℃, Zone 2 185℃, Zone 3 195℃, Zone 4 200℃, Zone 5 205℃, Zone 6 205℃, Zone 7 200℃, Zone 8 195℃, and the die head 200℃. The main extruder speed is 280 r / min, and the feed speed is 15 r / min. After the material is melt-blended, it is extruded from the die head, sequentially cooled by a water-cooling tank, pelletized by a pelletizer, and then dried in an 80℃ forced-air drying oven for 4 hours to obtain the high flame-retardant and easily colored recycled ABS composite material.

[0031] Example 2 A highly flame-retardant and easily colorable recycled ABS composite material is prepared by the following steps: S1. Weigh the following raw material components according to the following mass percentages: 78% recycled ABS, 10% aluminum diethylphosphinate (ADP), 6% melamine pyrophosphate (MPP), 2.5% silane-modified zinc borate (SZB-2), and 3.5% methyl methacrylate-butadiene-styrene copolymer (MBS). Add the above components to a high-speed mixer and mix at 800 r / min for 5 min to obtain a homogeneous mixture. S2. The uniform mixture is added to a twin-screw extruder. The temperatures of each section of the twin-screw extruder from the feeding section to the die head are set as follows: Zone 1 175℃, Zone 2 185℃, Zone 3 195℃, Zone 4 200℃, Zone 5 205℃, Zone 6 205℃, Zone 7 200℃, Zone 8 195℃, and the die head 200℃. The main extruder speed is 300 r / min, and the feeding speed is 18 r / min. After the material is melt-blended, it is extruded from the die head, sequentially cooled by a water-cooling tank, pelletized by a pelletizer, and then dried in an 80℃ forced-air drying oven for 4 hours to obtain the high flame-retardant and easily colored recycled ABS composite material.

[0032] Example 3 A highly flame-retardant and easily colorable recycled ABS composite material is prepared by the following steps: S1. Weigh the following raw material components according to the following mass percentages: 70% recycled ABS, 15% aluminum diethylphosphinate (ADP), 8% melamine pyrophosphate (MPP), 3% silane-modified zinc borate (SZB-2), and 4% methyl methacrylate-butadiene-styrene copolymer (MBS). Add the above components to a high-speed mixer and mix at 800 r / min for 5 min to obtain a homogeneous mixture. S2. The uniform mixture is added to a twin-screw extruder. The temperatures of each section of the twin-screw extruder from the feeding section to the die head are set as follows: Zone 1 175℃, Zone 2 185℃, Zone 3 195℃, Zone 4 200℃, Zone 5 205℃, Zone 6 205℃, Zone 7 200℃, Zone 8 195℃, and the die head 200℃. The main extruder speed is 350 r / min, and the feeding speed is 20 r / min. After the material is melt-blended, it is extruded from the die head, sequentially cooled by a water-cooling tank, pelletized by a pelletizer, and then dried in an 80℃ forced-air drying oven for 4 h to obtain the high flame-retardant and easily colored recycled ABS composite material.

[0033] Example 4 A highly flame-retardant and easily colorable recycled ABS composite material is prepared by the following steps: S1. Weigh the following raw material components according to the following mass percentages: 77.1% recycled ABS, 10% aluminum diethylphosphinate (ADP), 6% melamine pyrophosphate (MPP), 2.5% silane-modified zinc borate (SZB-2), 3.5% methyl methacrylate-butadiene-styrene copolymer (MBS), 0.5% antioxidant (a mixture of antioxidant 1098 and antioxidant 168 in a 1:1 mass ratio), and 0.4% pentaerythritol stearate (lubricant). Add the above components to a high-speed mixer and mix at 800 r / min for 5 min to obtain a homogeneous mixture. S2. The uniform mixture is added to a twin-screw extruder. The temperatures of each section of the twin-screw extruder from the feeding section to the die head are set as follows: Zone 1 175℃, Zone 2 185℃, Zone 3 195℃, Zone 4 200℃, Zone 5 205℃, Zone 6 205℃, Zone 7 200℃, Zone 8 195℃, and the die head 200℃. The main extruder speed is 300 r / min, and the feeding speed is 18 r / min. After the material is melt-blended, it is extruded from the die head, sequentially cooled by a water cooling tank, pelletized by a pelletizer, and then dried in an 80℃ forced-air drying oven for 4 h to obtain the high flame-retardant and easily colored recycled ABS composite material.

[0034] Example 5 A highly flame-retardant and easily colorable recycled ABS composite material is prepared by the following steps: S1. Weigh the following raw material components according to the following mass percentages: 83.4% recycled ABS, 6% aluminum diethylphosphinate (ADP), 5% melamine pyrophosphate (MPP), 1.2% silane-modified zinc borate (SZB-1), 3.5% methyl methacrylate-butadiene-styrene copolymer (MBS), 0.4% antioxidant (a mixture of antioxidant 1098 and antioxidant 168 in a 1:1 mass ratio), and 0.5% pentaerythritol stearate (lubricant). Add the above components to a high-speed mixer and mix at 800 r / min for 5 min to obtain a homogeneous mixture. S2. The homogeneous mixture is added to a twin-screw extruder. The temperatures of each section of the twin-screw extruder from the feeding section to the die head are set as follows: Zone 1 175℃, Zone 2 185℃, Zone 3 195℃, Zone 4 200℃, Zone 5 205℃, Zone 6 205℃, Zone 7 200℃, Zone 8 195℃, and the die head 200℃. The main extruder speed is 280 r / min, and the feeding speed is 15 r / min. After the material is melt-blended, it is extruded from the die head, sequentially cooled by a water-cooling tank, pelletized by a pelletizer, and then dried in an 80℃ forced-air drying oven for 4 h to obtain the high flame-retardant and easily colored recycled ABS composite material.

[0035] Example 6 A highly flame-retardant and easily colorable recycled ABS composite material is prepared by the following steps: S1. Weigh the following raw material components according to the following mass percentages: 70% recycled ABS, 15% aluminum diethylphosphinate (ADP), 7% melamine pyrophosphate (MPP), 3% silane-modified zinc borate (SZB-3), 4% methyl methacrylate-butadiene-styrene copolymer (MBS), 0.5% antioxidant (a mixture of antioxidant 1098 and antioxidant 168 in a 1:1 mass ratio), and 0.5% pentaerythritol stearate (lubricant). Add the above components to a high-speed mixer and mix at 800 r / min for 5 min to obtain a homogeneous mixture. S2. The uniform mixture is added to a twin-screw extruder. The temperatures of each section of the twin-screw extruder from the feeding section to the die head are set as follows: Zone 1 175℃, Zone 2 185℃, Zone 3 195℃, Zone 4 200℃, Zone 5 205℃, Zone 6 205℃, Zone 7 200℃, Zone 8 195℃, and the die head 200℃. The main extruder speed is 350 r / min, and the feeding speed is 20 r / min. After the material is melt-blended, it is extruded from the die head, sequentially cooled by a water-cooling tank, pelletized by a pelletizer, and then dried in an 80℃ forced-air drying oven for 4 h to obtain the high flame-retardant and easily colored recycled ABS composite material.

[0036] Example 7 A highly flame-retardant and easily colorable recycled ABS composite material is prepared by the following steps: S1. Weigh the following raw material components according to the following mass percentages: 75.4% recycled ABS, 12% aluminum diethylphosphinate (ADP), 6.5% melamine pyrophosphate (MPP), 2% silane-modified zinc borate (SZB-2), 3.2% methyl methacrylate-butadiene-styrene copolymer (MBS), 0.4% antioxidant (a mixture of antioxidant 1098 and antioxidant 168 in a 1:1 mass ratio), and 0.5% pentaerythritol stearate (lubricant). Add the above components to a high-speed mixer and mix at 800 r / min for 5 min to obtain a homogeneous mixture. S2. The uniform mixture is added to a twin-screw extruder. The temperatures of each section of the twin-screw extruder from the feeding section to the die head are set as follows: Zone 1 175℃, Zone 2 185℃, Zone 3 195℃, Zone 4 200℃, Zone 5 205℃, Zone 6 205℃, Zone 7 200℃, Zone 8 195℃, and the die head 200℃. The main extruder speed is 320 r / min, and the feeding speed is 18 r / min. After the material is melt-blended, it is extruded from the die head, sequentially cooled by a water cooling tank, pelletized by a pelletizer, and then dried in an 80℃ forced-air drying oven for 4 h to obtain the high flame-retardant and easily colored recycled ABS composite material.

[0037] Example 8 A highly flame-retardant and easily colorable recycled ABS composite material is prepared by the following steps: S1. Weigh the following raw material components according to the following mass percentages: 80.8% recycled ABS, 8% aluminum diethylphosphinate (ADP), 5.5% melamine pyrophosphate (MPP), 1.8% silane-modified zinc borate (SZB-2), 3% methyl methacrylate-butadiene-styrene copolymer (MBS), 0.4% antioxidant (a mixture of antioxidant 1098 and antioxidant 168 in a 1:1 mass ratio), and 0.5% pentaerythritol stearate (lubricant). Add the above components to a high-speed mixer and mix at 800 r / min for 5 min to obtain a homogeneous mixture. S2. The homogeneous mixture is added to a twin-screw extruder. The temperatures of each section of the twin-screw extruder from the feeding section to the die head are set as follows: Zone 1 175℃, Zone 2 185℃, Zone 3 195℃, Zone 4 200℃, Zone 5 205℃, Zone 6 205℃, Zone 7 200℃, Zone 8 195℃, and the die head 200℃. The main extruder speed is 290 r / min, and the feed speed is 16 r / min. After the material is melt-blended, it is extruded from the die head, sequentially cooled by a water-cooling tank, pelletized by a pelletizer, and then dried in an 80℃ forced-air drying oven for 4 h to obtain the high flame-retardant and easily colored recycled ABS composite material.

[0038] Comparative Example 1 The method was implemented in accordance with Example 2, except that silane-modified zinc borate was not added. The raw material composition was: 80.5% recycled ABS, 10% aluminum diethylphosphinate (ADP), 6% melamine pyrophosphate (MPP), and 3.5% methyl methacrylate-butadiene-styrene copolymer (MBS).

[0039] Comparative Example 2 The method was implemented as in Example 2, except that an equal amount of unmodified zinc borate powder (particle size 3~5 µm) was used instead of silane-modified zinc borate (SZB-2).

[0040] Comparative Example 3 The method was implemented as in Example 2, except that methyl methacrylate-butadiene-styrene copolymer (MBS) was not added. The raw material composition was: 81.5% recycled ABS, 10% aluminum diethylphosphinate (ADP), 6% melamine pyrophosphate (MPP) and 2.5% silane-modified zinc borate (SZB-2).

[0041] Comparative Example 4 The method was implemented in accordance with Example 2, except that melamine pyrophosphate (MPP) was not added. The raw material composition was: 78% recycled ABS, 16% aluminum diethylphosphinate (ADP), 2.5% silane-modified zinc borate (SZB-2), and 3.5% methyl methacrylate-butadiene-styrene copolymer (MBS).

[0042] Comparative Example 5 The method was implemented in accordance with Example 2, except that aluminum diethylphosphonate (ADP) was not added, and the raw material composition was: 78% recycled ABS, 16% melamine pyrophosphate (MPP), 2.5% silane-modified zinc borate (SZB-2), and 3.5% methyl methacrylate-butadiene-styrene copolymer (MBS).

[0043] Comparative Example 6 The method was implemented in accordance with Example 2, except that the mass percentages of each component were adjusted as follows: 60% recycled ABS, 20% aluminum diethylphosphinate (ADP), 10% melamine pyrophosphate (MPP), 5% silane-modified zinc borate (SZB-2), and 5% methyl methacrylate-butadiene-styrene copolymer (MBS).

[0044] Test case Flame retardancy test: The flame retardancy rating was tested using the vertical burning method according to UL94 standard. The sample size was 125 mm × 13 mm × 1.6 mm. Mechanical property testing: Tensile strength was tested according to GB / T 1040.2 standard, with a tensile rate of 50 mm / min; Notched impact strength of simply supported beam was tested according to GB / T 1043.1 standard. Coloring performance test: The composite material granules prepared in each example and comparative example were blended and granulated with 1% carbon black masterbatch in a twin-screw extruder, and then injection molded into standard color plates (80 mm × 60 mm × 2 mm). The L* value (brightness), a* value (red-green hue), and b* value (yellow-blue hue) of the color plates were tested using an X-Rite Ci7800 spectrophotometer (D65 light source, 10° standard observation angle). The standard color plate, which was injection molded from pure virgin ABS (same type, non-recycled) and 1% carbon black masterbatch, was used as a reference sample. The color difference value ΔE* = √(ΔL*² + Δa*² + Δb*²) was calculated. At the same time, the appearance defects such as yellowing, graying, color spots, and uneven coloring on the surface of the color plate were visually evaluated.

[0045] The ABS composite materials prepared in Examples 1-8 and Comparative Examples 1-6 were subjected to flame retardant performance tests, mechanical property tests, and coloring performance tests, respectively. The test results are shown in Table 1. Table 1

[0046] As shown in Table 1, all embodiments achieved a UL94 V-0 flame retardant rating, with tensile strengths ranging from 34.5 to 38.2 MPa and notched impact strengths from 8.5 to 10.5 kJ / m². The ΔE* values ​​for all embodiments were within the range of 0.2 to 0.9 (<1.5), exhibiting color differences that were virtually imperceptible to the naked eye and without any yellowing or graying. This indicates that the combination of the ADP-MPP-silane-modified zinc borate phosphorus-nitrogen-zinc ternary flame retardant synergistic system and the MBS dispersion-stabilization-toughening synergistic system of this application can simultaneously achieve high-efficiency flame retardancy, excellent colorability, and good mechanical properties within the range of 70% to 85% recycled ABS material content.

[0047] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application.

Claims

1. A highly flame-retardant, easily colorable, recyclable ABS composite material, characterized in that, The total mass of the raw material components of the recycled ABS composite material is 100%, including: 70-85% recycled ABS, 6-15% aluminum diethylphosphinate, 5-8% melamine pyrophosphate, 1.5-3% silane-modified zinc borate and 2.5-4% methyl methacrylate-butadiene-styrene copolymer.

2. The high flame-retardant, easily colorable, recyclable ABS composite material according to claim 1, characterized in that, The preparation method of the silane-modified zinc borate includes the following steps: (1) Add zinc borate powder to deionized water and ultrasonically disperse for 30-40 min to form a dispersion system. Then add dispersant to the dispersion system, adjust the pH to 8.0-9.0, and stir at 60-70 °C for 1-1.5 h to obtain zinc borate dispersion. (2) Add γ-aminopropyltriethoxysilane dropwise to the zinc borate dispersion. After the addition is complete, raise the temperature to 80~85℃ and keep it at a constant temperature for 2~3 h. After the heat preservation is completed, cool it down, and then centrifuge, wash and vacuum dry in sequence to obtain silane-modified zinc borate.

3. The high flame-retardant, easily colorable, recyclable ABS composite material according to claim 2, characterized in that, The mass ratio of zinc borate powder, deionized water, dispersant, and γ-aminopropyltriethoxysilane is 100:400~500:1~2:3~5.

4. The high flame-retardant, easily colorable, recyclable ABS composite material according to claim 2, characterized in that, The particle size of the zinc borate powder is 3~5 µm.

5. The high flame-retardant, easily colorable, recyclable ABS composite material according to claim 2, characterized in that, The dispersant is sodium dodecylbenzenesulfonate and / or polyethylene glycol.

6. The high flame-retardant, easily colorable, recyclable ABS composite material according to claim 1, characterized in that, The ABS recycled material has a melt flow index of 15~18 g / 10 min at 220 ℃ / 10 kg, and the test standard is ISO 1133-1-2011; the ABS recycled material has an impact strength of 8~10 KJ / m² at the test standard of ISO 179-2. 2 .

7. The high flame-retardant, easily colorable, recyclable ABS composite material according to claim 1, characterized in that, The raw material components of the recycled ABS composite material also include 0.3-0.5% antioxidant and 0.3-0.5% lubricant.

8. The high flame-retardant, easily colorable, recyclable ABS composite material according to claim 7, characterized in that, The antioxidant is a mixture of antioxidant 1098 and antioxidant 168 in a mass ratio of 1:

1.

9. The high flame-retardant, easily colorable, recyclable ABS composite material according to claim 7, characterized in that, The lubricant is pentaerythritol stearate.

10. A method for preparing the high flame-retardant and easily colorable recycled ABS composite material according to any one of claims 1 to 9, characterized in that, The preparation method includes the following steps: S1. The ABS recycled material, aluminum diethylphosphinate, melamine pyrophosphate, silane-modified zinc borate, and methyl methacrylate-butadiene-styrene copolymer are mixed in a mass percentage ratio to obtain a uniform mixture. S2. Add the mixture to a twin-screw extruder and sequentially perform melt blending, extrusion, water cooling, pelletizing, and drying to obtain the high flame retardant and easily colorable recycled ABS composite material. The temperature of each section of the twin-screw extruder is 175~205 ℃, and the main machine speed is 280~350 r / min.

Images