A low smoke density flame retardant ABS alloy material and preparation method thereof

Abstract

The present invention relates to a low-smoke-density flame-retardant ABS alloy material and a preparation method thereof, comprising ABS resin, a phosphorus-based flame-retardant masterbatch, fumed silica, a silicon-based flame-retardant synergist, PTFE, a compatibilizer, and other additives. The preparation method comprises: (a) mixing the fumed silica, silicon-based synergist, and PTFE under high pressure and stirring, and filling with nitrogen for pressurized protection before stirring; (b) uniformly mixing the other components and feeding them into an extruder through the main feed port; and (c) injecting the mixture obtained in step (a) through the side feed port of the extruder via a high-pressure injection pump, blending and granulating, thereby obtaining a product, a low-smoke-density flame-retardant ABS alloy material. This invention has excellent flame retardancy and smoke density reduction effects while maintaining the high impact resistance of the ABS alloy material. The ingredients are inexpensive and can be widely used in daily necessities such as automotive interior decoration parts, large household appliance housings, small household appliance housings, etc., reducing the harm caused by fire to people, and has broad application prospects.

Description

Technical Field

[0001] The invention belongs to the field of polymer blending and polymer molding processing, and particularly relates to a low-smoke density flame-retardant ABS alloy material and a preparation method thereof. Background Art

[0002] ABS alloy is a widely used engineering plastic, often found in automotive interior and exterior trim, large and small appliance housings, and other products. In everyday use, especially indoors and in vehicles, ABS alloy is highly susceptible to fire, potentially causing harm to the human body. Therefore, flame retardancy is often required in these applications. Furthermore, in some enclosed environments, the smoke produced by polymer combustion can cause secondary damage to the human body, necessitating stricter smoke density requirements.

[0003] Currently available low-smoke density flame-retardant ABS alloy materials often contain fillers such as aluminum hydroxide and magnesium hydroxide, which compromises the physical properties of the ABS alloy and makes it unsuitable for use under certain high-impact requirements. The present invention employs high-pressure, high-speed mixing of fumed silica and a silicon-based flame retardant synergist to form a crosslinked network. The PTFE undergoes fiberization during the high-speed mixing process, forming a double network with the fumed silica and the synergistic flame retardant. This double network, composed of non-combustible silica and PTFE, expands as the pressure drops, coating the plastic substrate. During combustion, this double network, composed entirely of non-combustible silica and PTFE, tightly wraps around the plastic substrate, effectively isolating it from external heat transfer and the escape of low-molecular-weight fragments. This prevents combustion, reduces smoke production, and mitigates fire hazards. Furthermore, solid carbon particles generated during combustion are absorbed by the highly porous fumed silica, preventing them from escaping. This effectively reduces smoke emission and density during combustion, thus preventing secondary harm to the human body caused by the smoke generated by combustion. This invention has excellent flame retardancy and smoke density reduction effects, while maintaining the high impact resistance of ABS alloy materials and low ingredient costs. It can be widely used in daily necessities such as automotive interiors, large household appliance casings, small household appliance casings, etc., reducing the harm of fire to people and has broad application prospects. Summary of the Invention

[0004] The purpose of the present invention is to provide a low smoke density flame retardant ABS alloy material and a preparation method thereof in response to the problems existing in the prior art.

[0005] The purpose of the present invention can be achieved by the following solutions:

[0006] The present invention provides a low smoke density flame retardant ABS alloy material, comprising the following components in parts by weight:

[0007]

[0008] Furthermore, the relative molecular weight of the ABS resin is 80,000-150,000, wherein the rubber content is 5-30 wt%, the acrylonitrile content is 10-30 wt%, and the styrene content is 40-70 wt%.

[0009] Furthermore, the phosphorus-based flame retardant masterbatch comprises 60-80% by weight of a PC matrix and 20-40% by weight of an organophosphorus flame retardant. The organophosphorus flame retardant comprises a polyaryl phosphate; the PC resin has a relative molecular weight of 15,000-30,000 and a glass transition temperature of 140-150°C. The phosphorus-based flame retardant masterbatch is obtained by mixing PC and the organophosphorus flame retardant, followed by extrusion and pelletization in a twin-screw extruder. Specifically, the PC and organophosphorus flame retardant are added in proportion to each other in a mixing barrel, mixed thoroughly in a mixer, and then extruded and pelletized in a twin-screw extruder for later use. The twin-screw extruder has a barrel temperature of 220-270°C, a screw speed of 200-600 rpm, and a pressure of 1.5-2.5 MPa.

[0010] Furthermore, the particle size range D50 of the fumed silica is 3-10 μm, and the porosity is greater than 90%. The fumed silica is artificially synthesized.

[0011] Furthermore, the silicone flame retardant synergist comprises acrylate grafted modified silane rubber. The silicone flame retardant synergist has a core-shell structure and a particle size of 200-300 nm. This particle size allows for good dispersion in the matrix and has a synergistic effect of toughening and flame retardancy.

[0012] Furthermore, the PTFE is pure PTFE powder;

[0013] Furthermore, the compatibilizer is AS-GMA, wherein the GMA content is 1-5%.

[0014] Furthermore, the other additives include lubricants, antioxidants, and ultraviolet absorbers.

[0015] The present invention also provides a method for preparing the low smoke density flame retardant ABS alloy material, the method comprising the following steps:

[0016] (a) mixing and stirring fumed silica, a silicon-based flame retardant synergist, and PTFE, and prior to stirring, filling the reactor with protective gas for pressurization protection, raising the pressure in the reactor to 2-4 MPa, and then stirring;

[0017] (b) mixing the other components uniformly and feeding the mixture into a twin-screw extruder through the main feed port;

[0018] (c) The mixture obtained in step (a) is injected from the side feed port of a twin-screw extruder through a high-pressure injection pump at an injection pressure of 2-4 MPa, and blended and granulated. After melt extrusion and granulation, the low smoke density flame retardant ABS alloy material is obtained.

[0019] Furthermore, in step (a), the stirring speed is 2500-3000 rpm, and the time is 20-40 minutes; the protective gas includes nitrogen; and the stirring is carried out at room temperature and at high speed in a high-pressure blender.

[0020] Furthermore, in step (c), the barrel temperature of the twin-screw extruder is 220-270° C., the screw speed is 200-600 rpm, and the pressure is 1.5-2.5 MPa.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The present invention crosslinks fumed silica and a silicon-based flame retardant synergist through high-pressure, high-speed stirring to form a crosslinked network. Other flame retardant synergists cannot form a network structure and cannot crosslink with silica to produce a mesh-like coating effect. PTFE fiberizes during the high-speed stirring process, forming a double network with the fumed silica and the silicon-based synergistic flame retardant. The PTFE is injected into the extruder via a high-pressure injection molding pump. As the pressure drops, the double network expands and coats the plastic substrate. During the combustion process, this double network, composed of non-combustible silica and PTFE, tightly coats the surface of the plastic substrate, effectively isolating it from external heat transfer and the escape of internal low-molecular-weight fragments, promptly preventing combustion, reducing smoke production, and minimizing fire hazards.

[0023] (2) The solid carbon particles produced in the early stage of combustion will be adsorbed by the high-porosity fumed silica and will not be able to overflow, which effectively reduces the smoke overflow during material combustion, reduces the smoke density, avoids the secondary damage to the human body caused by the smoke produced by combustion, and has the effect of flame retardant and reducing smoke density. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several variations and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0025] The raw materials used in the following examples and comparative examples are as follows: ABS resin is ABS8391, produced by Gaoqiao Petrochemical; PC resin in the phosphorus flame retardant masterbatch is Asahi Kasei's L-1250Y, with a content of 80%, and phosphorus flame retardant is RDP, with a content of 20%; the phosphorus flame retardant masterbatch is prepared by blending PC and phosphorus flame retardant and stirring them uniformly, then adding them to a twin-screw extruder to extrude the masterbatch, and the temperature of the feed section of the twin-screw extruder is 220°C, the temperature of the plasticizing section is 240°C, and the temperature of the homogenizing section is 260°C. The screw speed is 400 rpm and the pressure is 2.5 MPa; the D50 value of the fumed silica is 4 μm, from Nano Technology, and the porosity is greater than 90%; the silicone flame retardant synergist S-2001 is from Mitsubishi Rayon; the PTFE is A3800 from Mitsubishi; the compatibilizer is SAG001, from Rizhisheng Fine Chemicals; other additives include the antioxidant B900 (Ciba Specialty Chemicals), the UV absorber Tinuvins UVP (Ciba), and the lubricant barium stearate, with the weight ratio of each additive being 1:1:1.

[0026] The ABS alloy materials prepared in Examples 1 to 5 and Comparative Examples 1 to 5 were dried at 80° C. for 5 h and then injection molded into test specimens under the same injection molding conditions according to ASTM standards for physical property testing. They were also injection molded into test bars according to UL standards for flame retardancy testing. Test specimens were also injection molded under the same conditions and subjected to smoke density testing according to ISO 5659-2:2006, IDT standards. Specific test standards and conditions are shown in Table 1.

[0027] Table 1

[0028] Physical properties Test conditions Test standards MFR (g / 10min) 250℃22.162g ASTM D1238-10 Izod notched impact strength (1 / 8) (J / m) 23℃ ASTM D256-10 Tensile strength (MPa) 50mm / min ASTM D638-10 Flexural strength (MPa) 3mm / min ASTM D790-10 Flexural modulus (MPa) 3mm / min ASTM D790-10 Vicat(℃) 52g2 50℃ / h ASTM D1525-09 Flame retardant properties 1.6mm UL-94 Smoke density test 75mm*75mm*12.5mm ISO 5659-2:2006

[0029] Example 1

[0030] This embodiment provides a low smoke density flame retardant ABS alloy material and a preparation method thereof. The weight proportions of the raw materials are shown in Table 2. The specific steps are as follows:

[0031] (1) Add fumed silica, silicon-based synergist, and PTFE into a high-pressure blender and stir at high speed. Before stirring, fill the blender with nitrogen for pressurization protection to increase the pressure in the reactor to 4 MPa. Stir at a stirring speed of 3000 rpm at room temperature for 30 minutes.

[0032] (2) Mix the other components evenly in a mixing barrel and feed them into a twin-screw extruder through the main feed port;

[0033] (3) The mixture obtained in step (1) is injected from the side feed port of the extruder through a high-pressure injection pump at a pressure of 4 MPa, and is blended and granulated. The product is obtained by melt extrusion and granulation to obtain a low smoke density flame retardant ABS alloy material product.

[0034] The above materials are melt-extruded, cooled, dried, and pelletized to obtain samples; wherein, the twin-screw extruder is a co-rotating twin-screw extruder, the aspect ratio of the screw is 40:1, and the screw barrel is provided with a vacuum pumping device and a temperature control device; the feeding section temperature of the twin-screw extruder is 160°C, the plasticizing section temperature is 220°C, the homogenizing section temperature is 240°C, the screw speed is 400rpm, and the pressure is 2.5MPa.

[0035] Example 2

[0036] This embodiment provides a low smoke density flame retardant ABS alloy material and a preparation method thereof. The weight proportions of the raw materials are shown in Table 2. The preparation method is the same as that of Example 1.

[0037] Example 3

[0038] This embodiment provides a low smoke density flame retardant ABS alloy material and a preparation method thereof. The weight proportions of the raw materials are shown in Table 2. The preparation method is the same as that of Example 1.

[0039] Example 4

[0040] This embodiment provides a low smoke density flame retardant ABS alloy material and a preparation method thereof. The weight proportions of the raw materials are shown in Table 2. The preparation method is the same as that of Example 1.

[0041] Example 5

[0042] This embodiment provides a low smoke density flame retardant ABS alloy material and a preparation method thereof. The weight proportions of the raw materials are shown in Table 2. The preparation method is the same as that of Example 1.

[0043] Comparative Example 1

[0044] This comparative example provides a low smoke density flame retardant ABS alloy material and a preparation method thereof. The weight proportions of the raw materials are shown in Table 2. The preparation method is the same as that of Example 1.

[0045] Comparative Example 2

[0046] This comparative example provides a low smoke density flame retardant ABS alloy material and a preparation method thereof. The weight proportions of the raw materials are shown in Table 2. The preparation method is the same as that of Example 1.

[0047] Comparative Example 3

[0048] This comparative example provides a low smoke density flame retardant ABS alloy material and a preparation method thereof. The weight proportions of the raw materials are shown in Table 2. The preparation method is the same as that of Example 1.

[0049] Comparative Example 4

[0050] This comparative example provides a low smoke density flame-retardant ABS alloy material and a preparation method thereof. The weight proportions of the raw materials are shown in Table 2. All materials are directly added to a mixing barrel and mixed evenly without stirring in a high-speed stirrer, and then extruded and granulated. Other preparation methods are the same as in Example 1.

[0051] Comparative Example 5

[0052] This comparative example provides a low smoke density flame-retardant ABS alloy material and a preparation method thereof. The weight proportions of the raw materials are shown in Table 2. Fumed silica, a silicon-based synergist, and PTFE are mixed under normal pressure, injected from a side feed port under normal pressure, and then extruded and granulated. Other preparation methods are the same as those in Example 1.

[0053] Table 2

[0054]

[0055]

[0056] The physical properties and smoke density test results of the ABS resins of Examples 1 to 5 and Comparative Examples 1 to 5 are shown in Table 3 below.

[0057] Table 3

[0058]

[0059] The test results of Examples 1-5 and Comparative Examples 1-5 in Table 3 indicate that the dual network structure composed of the silicon-based flame retardant synergist, fumed silica, and PTFE effectively isolates external heat propagation and internal low-molecular-weight fragments from the atmosphere. Furthermore, the high porosity of silica adsorbs smoke particles through the gas phase, giving the sample excellent flame retardancy and low smoke density properties.

[0060] The present invention has many specific application paths, and the above is only a preferred embodiment of the present invention. It should be noted that the above embodiments are only used to illustrate the present invention and are not intended to limit the scope of protection of the present invention. For those skilled in the art, several improvements can be made without departing from the principles of the present invention, and these improvements should also be considered as the scope of protection of the present invention.

Claims

1. A method for preparing a low smoke density flame retardant ABS alloy material, characterized in that: The low smoke density flame retardant ABS alloy material comprises the following components in parts by weight: The silicon-based flame retardant synergist includes acrylate grafted modified silane rubber; The preparation method comprises the following steps: (a) mixing and stirring fumed silica, a silicon-based flame retardant synergist, and PTFE. Prior to stirring, the mixture was pressurized with a protective gas until the pressure in the reactor reached 2-4 MPa. The stirring was continued at a speed of 2500-3000 rpm for 20-40 minutes. (b) mixing the other components uniformly and feeding the mixture into a twin-screw extruder through the main feed port; (c) The mixture obtained in step (a) is injected from the side feed port of a twin-screw extruder through a high-pressure injection pump at an injection pressure of 2-4 MPa, and blended and granulated. After melt extrusion and granulation, the low smoke density flame retardant ABS alloy material is obtained.

2. The method for preparing a low smoke density flame retardant ABS alloy material according to claim 1, characterized in that: The relative molecular weight of the ABS resin is 80,000-150,000, wherein the rubber content is 5-30wt%, the acrylonitrile content is 10-30wt%, and the styrene content is 40-70wt%.

3. The method for preparing a low smoke density flame retardant ABS alloy material according to claim 1, characterized in that: The phosphorus-based flame retardant masterbatch comprises a base PC resin with a mass content of 60-80% and an organic phosphorus flame retardant with a mass content of 20-40%.

4. The method for preparing a low smoke density flame retardant ABS alloy material according to claim 3, characterized in that: The organic phosphorus flame retardant includes polyaryl phosphate; the relative molecular weight of the matrix PC resin is 15000-30000, and the glass transition temperature is 140-150 DEG C.

5. The method for preparing a low smoke density flame retardant ABS alloy material according to claim 1, characterized in that: The particle size range D50 of the fumed silica is 3-10 μm, and the porosity is greater than 90%.

6. The method for preparing a low smoke density flame retardant ABS alloy material according to claim 1, characterized in that: The compatibilizer is AS-GMA, wherein the GMA content is 1-5%.

7. The method for preparing a low smoke density flame retardant ABS alloy material according to claim 1, characterized in that: In step (c), the barrel temperature of the twin-screw extruder is 220-270° C., the screw speed is 200-600 rpm, and the pressure is 1.5-2.5 MPa.

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