Halogen-free flame-retardant ABS composite material, preparation method and application thereof

Abstract

The application discloses a kind of halogen-free flame-retardant ABS composite materials, by weight fraction, including following raw material components: ABS resin 26-50 parts, PLA resin 25-35 parts, compatible agent 5-12 parts, toughening agent 5-12 parts, phosphorus flame retardant 6-15 parts, nitrogen flame retardant 2-5 parts.The application is alloyed by ABS resin, PLA resin as resin matrix, and the alloy system compatibility is solved by compatible agent, the performance defects caused by the difference of resin polarity are overcome, toughening agent is added, the mechanical properties of alloy material are greatly improved, and the development of halogen-free flame-retardant performance is carried out, and the application has excellent comprehensive performance and halogen-free flame-retardant performance, and the alloy material has good industrial application value.

Description

Technical Field

[0001] This invention relates to the field of engineering plastics technology, specifically to a halogen-free flame-retardant ABS composite material. Background Technology

[0002] Bio-based polymers have emerged as valuable alternatives to fossil-based polymers, enabling the production of materials with reduced carbon footprints and independence from petrochemical products. Among them, polylactic acid (PLA) boasts numerous advantages, including high modulus, high strength, complete biodegradability, and similar molding and processing methods as petroleum-based resins, making it one of the most commercially successful biodegradable plastics in the past 20 years. It is widely used in packaging materials and the biomedical field. However, PLA's slow crystallization rate and low crystallinity result in poor heat resistance, and its poor toughness limits its application range. ABS resin possesses better heat resistance and higher toughness, and existing technologies have explored blending ABS with PLA to produce alloy materials.

[0003] However, ABS resin is a flammable material. When recommended for use in household appliances and electronic devices, its flammability must comply with the relevant provisions of the US UL-94 safety laboratory standard. Therefore, flame-retardant modification of ABS / PLA resin is particularly important. To address the flammability of ABS / PLA resin, existing technologies typically employ the following improvements: first, using phenylphosphodichloro as the main flame retardant, achieving a V-2 rating, but with poor impact resistance; second, using oligomer chain extenders to react with PLA and ABS to form new polymers, increasing the thermal flexural temperature, but with poor impact resistance.

[0004] Therefore, it is necessary to develop a PLA / ABS alloy with high impact resistance and better flame retardant properties that can be widely used in personal consumer electronics and home appliances. Summary of the Invention

[0005] In order to overcome the shortcomings or defects of the prior art, the present invention proposes a halogen-free flame-retardant ABS composite material.

[0006] This invention is achieved through the following technical solution:

[0007] A halogen-free flame-retardant ABS composite material, comprising the following raw material components by weight:

[0008] 26-50 parts of ABS resin

[0009] 25-35 parts of PLA resin

[0010] 6-15 parts of phosphorus-based flame retardant

[0011] 2-5 parts of nitrogen-based flame retardant

[0012] 5-12 parts compatibilizer

[0013] 5-12 parts toughening agent;

[0014] The PLA resin has a melt flow rate of 6.5-10 g / 10 min under the test conditions of 210℃ × 2.16 kg; the compatibilizer is any one of PET, PBT, PC, and PMMA.

[0015] The melt flow index and monomer ratio of the ABS resin are not particularly limited, but preferably, under the test conditions of 210℃×2.16kg, the melt flow rate is 10-15g / 10min, the acrylonitrile monomer ratio is 22wt%-25wt%, the butadiene monomer ratio is 18wt%-22wt%, and the styrene monomer ratio is 53wt%-60wt%.

[0016] In this invention, PLA resin is used to modify ABS resin. PLA resin mainly consists of ester bonds formed by the reaction of hydroxyl and carboxyl groups, and it exhibits optical activity. This improves the strength of the hard segments of ABS, softens the entire ABS molecular chain, reduces shrinkage, and enhances fluidity. Selecting PLA with a higher melt flow rate is more conducive to achieving a V-2 flame retardant rating. Secondly, this invention incorporates phosphorus and nitrogen-based flame retardants into the formulation to achieve a synergistic flame retardant effect, thus endowing the ABS material with flame retardant capabilities. The terminal carboxyl groups in the PLA molecular chain have a good affinity with phosphorus and nitrogen-based flame retardants, thereby enhancing their flame retardant effect on PLA-modified ABS. Furthermore, phosphorus-based flame retardants require an acid source to exert their flame retardant effect. Since PLA contains terminal carboxyl groups, it can also serve as an acid source, synergistically enhancing the flame retardant effect of phosphorus-based flame retardants during the flame retardant process. This allows for achieving a V-2 flame retardant rating even with reduced inorganic flame retardant dosage, thereby minimizing the impact of inorganic flame retardants on material toughness. Furthermore, by adding compatibilizers and toughening agents to the formulation, this invention achieves excellent compatibility among the components of the PLA / ABS system, resulting in PLA / ABS composite materials with superior flame retardancy and toughness. The inventors have also discovered that selecting any one of the polyester macromolecules PET, PBT, PC, or PMMA as the compatibilizer can resolve the differences in polarity among the alloy components, improve the dispersion uniformity of the phase interface, and comprehensively enhance the mechanical properties.

[0017] As a preferred embodiment, the structure of the nitrogen-based flame retardant is shown in Formula I below:

[0018]

[0019] Among them, R1, R2, and R3 are the same and independent of each other, and their structures are -NCH, -NO3, -NH2, -N(CH3) or -N2Cl.

[0020] As a preferred embodiment, the mass ratio of the phosphorus-based flame retardant to the nitrogen-based flame retardant is (3-7):1.

[0021] After extensive testing, this invention determined that a specific ratio of phosphorus-based flame retardant to nitrogen-based flame retardant can give the ABS composite material of this invention the best flame retardant, toughness and impact resistance properties.

[0022] As a preferred embodiment, the compatibilizer is PMMA or PC, more preferably a macromolecular PMMA containing an acrylate structure, with a melt flow rate of 9-12 g / 10 min (tested at 230°C and 3.8 kg) and the best mechanical properties.

[0023] As a preferred embodiment, the toughening agent is one of MBS, SBS, SEBS, and ASA. The toughening agent is preferably butadiene-styrene copolymer MBS with a core-shell structure. The synergistic use of MBS toughening agent and polyester compatibilizer helps to reduce the flame retardancy of ABS and improve the flame retardant efficiency.

[0024] Using butadiene-styrene copolymer with a core-shell structure as a toughening agent to toughen polylactic acid can more effectively improve the elongation at break, impact strength and tensile strength of polylactic acid, thus obtaining polylactic acid with good comprehensive properties.

[0025] In the polystyrene composition of the present invention, the content of ABS and PLA is not less than 45 wt%;

[0026] The composition of the present invention may further contain a lubricant and an antioxidant without impairing the effects of the present invention. The lubricant may be selected from EBS B50 of the amide class, and the antioxidant may be selected from SONOX 1010 of the hindered phenol class.

[0027] The preparation process of the halogen-free flame-retardant ABS composite material of the present invention specifically includes the following steps:

[0028] (1) Mix ABS resin, PLA resin, compatibilizer, toughening agent, phosphorus flame retardant and nitrogen flame retardant evenly in a mixer according to the proportion;

[0029] (2) The mixture obtained in step (1) is melted, mixed and extruded by a twin-screw extruder, granulated and dried to obtain the halogen-free flame-retardant ABS composite material.

[0030] Preferably, the mixer in step (1) is a high-speed mixer with a rotation speed of 1000-1200 r / min and a mixing time of 2-5 minutes.

[0031] Preferably, the temperature of the twin-screw extruder barrel in step (2) is controlled between 170-185°C, the length-to-diameter ratio of the twin-screw extruder is (38-41):1, and the screw speed is 300-500 rpm.

[0032] The application of the halogen-free flame-retardant ABS composite material described in this invention in the manufacture of electronic appliances or office supplies, particularly in chargers, UPS systems, printers, projectors, and other products in the field of electronic appliances or office supplies.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] The beneficial effects of this invention are as follows: This invention provides a halogen-free flame-retardant ABS composite material. By using ABS resin and PLA resin as resin matrices for alloying design and development, the compatibility of the alloy system is solved by using compatibilizers, overcoming the performance defects caused by the difference in resin polarity. At the same time, toughening agents are added, which greatly improves the mechanical properties of the alloy material. Halogen-free flame-retardant properties have also been developed. The halogen-free flame-retardant ABS composite material of this invention has excellent comprehensive performance and halogen-free flame-retardant properties, and the alloy material has good industrial application value. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. 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.

[0036] <Preparation of Examples and Comparative Examples>

[0037] The raw materials used in the embodiments and comparative examples of this invention are all commercially available, but are not limited to these materials:

[0038] ABS resin: Grade ABS8391, purchased from Sinopec Shanghai Gaoqiao Company;

[0039] PLA resin A: Grade PLA 4032D, purchased from Nature Works, USA, with a melt flow rate of 7.0 g / 10 min;

[0040] PLA resin B: grade PLA 4043D, purchased from Nature Works, USA, with a melt flow rate of 6.7 g / 10 min;

[0041] PLA resin C: grade PLA 4060D, purchased from Nature Works, USA, melt flow rate 5.6 g / 10 min;

[0042] PLA resin D: Grade PLA 3052D, purchased from Nature Works, USA, with a melt flow rate of 14 g / 10 min;

[0043] Phosphorus-based flame retardant: Hydroquinone bis(diphenyl phosphate), brand name WSFR-PX-220, purchased from Zhejiang Wansheng Company;

[0044] Nitrogen-based flame retardant: melamine cyanurate, brand name MCA, purchased from Sichuan Fine Chemical Research and Design Institute;

[0045] Compatibilizer A: Polymethyl methacrylate, brand name PMMA 20HR, purchased from SBIC China Co., Ltd.

[0046] Compatibilizer B: Polycarbonate, grade PC1300 10NP, purchased from LG Chem.

[0047] Compatibilizer C: Maleic anhydride grafted ABS compatibilizer, brand name KT-2, purchased from Shenyang Ketong Plastics Co., Ltd.

[0048] Toughening agent A: methacrylic acid-butadiene-styrene copolymer, brand name EM500, purchased from LG Chem.

[0049] Toughening agent B: Styrene-butadiene copolymer, brand name YH-792E, purchased from Sinopec Baling Petrochemical Company;

[0050] Toughening agent C: ASA substance, brand name A600N, purchased from Guangzhou Runfeng Chemical Co., Ltd.

[0051] The composite materials of the various embodiments and comparative examples of the present invention were prepared by the following process:

[0052] Weigh each component according to the formula, add it to a mixer and mix evenly to obtain a premix; feed the premix into a twin-screw extruder for compounding, extrusion and processing to obtain halogen-free flame-retardant ABS composite material. The twin-screw extruder has a speed of 300-500 rpm, a temperature of 170-185℃, and a length-to-diameter ratio of 40:1.

[0053] The examples and comparative examples were tested using the following methods or standards:

[0054] Cantilever beam notched impact strength: ISO 180-2000 (Type A notch), test conditions: 23℃, 4mm;

[0055] Flame retardancy rating: UL 94-2018, test sample thickness: 2.0mm;

[0056] Table 1. Formulations (parts by weight) of the composite materials in each embodiment.

[0057]

[0058] Table 2 Formulations (parts by weight) of composite materials for each comparative example

[0059]

[0060] Table 3 Performance test results of the embodiments

[0061]

[0062] Table 4 shows the performance test results of the comparative examples.

[0063]

[0064] As can be seen from the comparison of the examples and comparative examples in Tables 3 and 4, phosphate ester flame retardants and nitrogen-based flame retardants have good flame retardant effects in ABS / PLA composite materials. When used together, a stable V-2 flame retardant rating can be achieved at low addition levels. Compatibilizers can effectively solve the compatibility problem of composite materials, improve mechanical toughness, and overcome the poor mechanical properties of flame-retardant composite materials. Toughening agents can effectively improve the toughness of composite materials, giving them excellent comprehensive performance. The resulting material can achieve a V-2 vertical burning rating, and the cantilever beam notched impact strength can reach 12 kJ / m. 2 Compared to the standard, it has a clear advantage and can effectively meet the high standards of customers and the market.

[0065] Compared with Example 3, Comparative Examples 1-8 show that Comparative Example 1 only added phosphorus-based flame retardants and did not add nitrogen-based flame retardants, Comparative Example 2 only added nitrogen-based flame retardants and did not add phosphorus-based flame retardants, resulting in a decrease in the flame retardant performance of the materials. Comparative Example 3 had a small amount of PLA resin added, which resulted in the materials not achieving a good V-2 flame retardant rating. Comparative Example 4 had a low melt flow rate of PLA resin added, which could not play a role in assisting flame retardancy. Comparative Example 5 had a high melt flow rate of PLA resin added, which resulted in a decrease in the mechanical properties of the materials. Comparative Examples 6 and 7 did not add compatibilizers and toughening agents, respectively, so the mechanical properties of the materials could not be significantly improved. Comparative Example 8 added maleic anhydride-grafted ABS as a compatibilizer, which could not significantly improve the mechanical properties.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A halogen-free flame-retardant ABS composite material, characterized in that, By weight, it includes the following components: 26-50 parts of ABS resin 25-35 parts of PLA resin 6-15 parts of phosphorus-based flame retardant 2-5 parts of nitrogen-based flame retardant 5-12 parts compatibilizer 5-12 parts toughening agent; The PLA resin has a melt flow rate of 6.5-10 g / 10 min under the test conditions of 210℃×2.16 kg, and the compatibilizer is any one of PET, PBT, PC, and PMMA. The mass ratio of the phosphorus-based flame retardant to the nitrogen-based flame retardant is (3-7):

1.

2. The halogen-free flame-retardant ABS composite material according to claim 1, characterized in that, The structure of the nitrogen-based flame retardant is shown in Formula I below: Among them, R1, R2, and R3 are the same and independent of each other, and their structure is -NH2.

3. The halogen-free flame-retardant ABS composite material according to claim 1, characterized in that, The toughening agent is any one of MBS, SBS, SEBS, and ASA.

4. A method for preparing a halogen-free flame-retardant ABS composite material as described in any one of claims 1-3, characterized in that, Includes the following steps: (1) Mix ABS resin, PLA resin, compatibilizer, toughening agent, phosphorus flame retardant and nitrogen flame retardant evenly in a mixer according to the proportion; (2) The mixture obtained in step (1) is melted, mixed and extruded by a twin-screw extruder, granulated and dried to obtain the halogen-free flame-retardant ABS composite material.

5. The preparation method according to claim 4, characterized in that, The mixer mentioned in step (1) is a high-speed mixer with a rotation speed of 1000-1200 r / min and a mixing time of 2-5 minutes; and / or In step (2), the temperature of the twin-screw extruder barrel is controlled between 170-185℃, the length-to-diameter ratio of the twin-screw extruder is (38-41):1, and the screw speed is 300-500 rpm.

6. The application of the halogen-free flame-retardant ABS composite material as described in any one of claims 1-3 in the manufacture of electronic appliances or office supplies.

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