Impact-resistant flame-retardant ABS material and preparation method thereof

Abstract

The invention discloses an impact-resistant flame-retardant ABS (Acrylonitrile Butadiene Styrene) material and a preparation method thereof. The material is prepared from the following raw materials in parts by mass: 67-80 parts of ABS resin, 15-28 parts of an intumescent flame retardant, 5-8 parts of a flexibilizer, 2-5 parts of a compatilizer and 0.7 part of a processing aid, the intumescent flame retardant is composed of a piperazine flame retardant, a hypophosphite flame retardant and / or a nitrogen flame retardant. The flame-retardant ABS material disclosed by the invention has excellent mechanical properties and flame retardance at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to an impact-resistant and flame-retardant ABS material and a preparation method thereof. Background Art

[0002] ABS is a ternary polymer of acrylonitrile-butadiene-styrene, belonging to a hot-melt resin or a thermoplastic engineering plastic. The rubber butadiene part therein provides toughness, and the polystyrene-acrylonitrile copolymer provides hardness, rigidity and strength. It has excellent mechanical / electrical properties and chemical resistance, so it is widely used in industries such as electrical, construction, and automotive. However, ABS is highly flammable, with a limiting oxygen index of about 18%. When burning, it will produce dangerous molten droplets and toxic smoke, which limits its application. This makes the development of flame-retardant ABS crucial.

[0003] Common flame retardants for flame-retardant ABS include bromine-antimony systems. Due to their good flame retardant effect, they are the most widely used in the market. However, since they will release toxic chemicals when burning, which has an impact on the environment and ecology, their application is limited. With the partial halogen flame retardants being banned by the European Union, the flame retardancy has been transformed to halogen-free.

[0004] Currently, phosphorus-based flame retardants have a high phosphorus content, are environmentally friendly and halogen-free, and are friendly to the environment. They have excellent char-forming and flame retardant properties and are considered the most potential substitutes for halogen-based flame retardants. However, phosphorus-containing flame retardants also have some disadvantages, such as low compatibility with polyolefins, poor water resistance and environmental durability. And when more than 30% of intumescent flame retardants are used in ABS, it will cause the deterioration of the thermal stability and mechanical properties of the ABS resin, especially the decrease in impact strength. Therefore, reducing the load of the flame retardant and at the same time studying the practical application of ABS flame retardant materials with high flame retardancy and mechanical properties is of great significance. Summary of the Invention

[0005] To solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a high-impact halogen-free flame-retardant ABS material with excellent mechanical properties and flame retardant properties at the same time and a preparation method thereof.

[0006] The purpose of the present invention is achieved by the following technical solutions: An impact-resistant and flame-retardant ABS material, which is composed of the following raw materials in parts by mass: 67-80 parts of ABS resin, 15-28 parts of intumescent flame retardant, 5-8 parts of toughening agent, 2-5 parts of compatibilizer, and 0.7 part of processing aid; the intumescent flame retardant is composed of piperazine-based flame retardant, hypophosphite-based flame retardant and / or nitrogen-based flame retardant.

[0007] Preferably, the ABS resin is a general-purpose injection-grade ABS.

[0008] Preferably, the toughening agent is one or two of montmorillonite, low-density polyethylene, chlorinated polyethylene, EVA, and calcium stearate.

[0009] Preferably, the compatibilizer is POE-g-MAH.

[0010] Preferably, the 0.7 parts of processing aids include 0.4 parts of antioxidant and 0.3 parts of anti-dripping agent.

[0011] Preferably, the antioxidant is pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and the anti-dripping agent is polytetrafluoroethylene.

[0012] Preferably, the piperazine-based flame retardant is piperazine pyrophosphate, the hypophosphite-based flame retardant is aluminum hypophosphite or aluminum diethyl hypophosphite, and the nitrogen-based flame retardant is melamine polyphosphate.

[0013] The preparation method of the impact-resistant flame-retardant ABS material of the present invention is to bake the intumescent flame retardant and the toughening agent in an oven at 60°C for 8 hours, then mix them evenly, and then mix them evenly with the ABS resin, the compatibilizer, and the processing aids, and then send them into a screw extruder for melt extrusion, and then injection molding to obtain the impact-resistant flame-retardant ABS material.

[0014] The intumescent flame retardant of the present invention is composed of a carbon source, an acid source, and a gas source. When the flame retardant is heated, the acid source decomposes to produce inorganic acid, and the inorganic acid can react with the carbon source by esterification. At the same time, the gas source decomposes to produce a large amount of incombustible gas, and these gases cause the molten carbon layer generated by esterification to expand and foam, thereby forming a porous foam carbon layer, which can protect the base material from continuing to burn. By constructing a foam porous structure and generating a continuous and dense carbon layer to cover the surface of the polymer material, the heat and oxygen transfer between the flame zone and the underlying material are inhibited. The piperazine-based flame retardant simultaneously has the carbon source, acid source, and gas source molecular monomers. The hypophosphite has a high phosphorus content, which can further increase the acid source and gas source molecules. The melamine polyphosphate has a high nitrogen content, which can further increase the thickness and compactness of the carbon layer. The piperazine-based flame retardant can form an efficient intumescent carbonization flame retardant system with the hypophosphite and melamine polyphosphate, having better flame retardancy, heat resistance, and stability. In the formula of the halogen-free flame-retardant ABS composition of the present invention, through the compounding of the piperazine-based, hypophosphite-based, and phosphorus-nitrogen-based compounds, the flame retardants play a synergistic flame retardant effect, promoting the formation and compactness of the carbon layer, preventing the chain reaction, and diluting the concentration of combustibles. By using different ratios of flame retardants, the flame retardant performance of the product is improved, and by adding different proportions of toughening agents, the mechanical loss caused by the addition of flame retardants is reduced. The vertical flame retardant grade of the flame-retardant ABS material of the present invention passes the V-0 level, the appearance of the material remains unchanged, it has the technical value of mass production application, and has excellent mechanical properties, which can meet the material technical requirements of many fields such as electronic appliances and automobiles. Detailed Embodiments

[0015] The content of the present invention will be further described below in conjunction with specific embodiments.

[0016] Table 1 lists the formulations of the impact-resistant flame-retardant ABS materials in Examples 1 to 5 of the present invention and the common ABS materials in the prior art in Comparative Examples 1 and 2. The numbers in the table represent parts by mass.

[0017] Table 1 Material Formulations of Examples 1 to 5 and Comparative Examples 1 and 2 (parts by mass)

[0018] The method for preparing the impact-resistant flame-retardant ABS material using the raw materials with the formulations of Examples 1 to 5 is as follows: (1) Place the flame retardant and toughening agent in an oven respectively, and bake at 60°C for 8 hours to dry the moisture. (2) Feed the baked flame retardant and toughening agent into a mixer and mix evenly. An existing technology equipment can be used for the mixer. (3) Mix the ABS resin, compatibilizer, processing aid with the mixture of the flame retardant and toughening agent evenly again. (4) Feed the mixed material obtained in step (3) into a twin-screw extruder for melt extrusion, then cool with water and pelletize. An existing technology equipment is used for the twin-screw extruder, and the extrusion process parameters are: temperature 205 - 215°C, rotation speed 300 - 400 rpm, feeding rotation speed 15 - 20 Hz. (5) Feed the pellets obtained in step (4) into an injection molding machine for injection molding to obtain the impact-resistant flame-retardant ABS material.

[0019] Perform performance tests and evaluations on the impact-resistant flame-retardant ABS materials prepared from the raw materials with the formulations of the examples and comparative examples using the standards and test conditions listed in Table 2, and the results are shown in Table 3.

[0020] Table 2 Performance Test Standards and Conditions

[0021] Table 3 Performance Test Data of Examples 1 to 5 and Comparative Examples 1 and 2

[0022] Conclusion: As can be seen from Table 3, the addition of flame retardants improves the flame retardancy of the composite materials. The limiting oxygen index values of the examples after adding flame retardants are all above 25%. The limiting oxygen index value of Example 4 containing the flame retardants piperazine pyrophosphate and melamine polyphosphate is second only to that of Examples 2 and 3 containing hypophosphite. Secondly, except for Example 4 and Comparative Example 1, UL-94 all passes the V-0 level, and Examples 2, 3, and 5 have excellent flame retardancy. It can be seen that the flame retardants containing piperazine pyrophosphate and hypophosphite show excellent flame retardancy. When compounded with a small amount of melamine polyphosphate, the flame retardancy of the composite material is further improved.

[0023] However, the addition of flame retardants will deteriorate the impact strength of the ABS matrix. Through Example 1 and Comparative Example 2, the impact strength (toughness) of adding a certain toughening agent material will be improved. Compared with other toughening agents, calcium stearate and polystyrene have better impact performance and flame retardancy, and calcium stearate has less influence on the impact performance.

[0024] The above examples are only used to illustrate the technical solutions of the present invention, rather than limiting the protection scope of the present invention. Those of ordinary skill in the art should understand that within the scope defined by the claims of the present invention, they can still modify the technical solutions recorded in the foregoing examples, or perform equivalent replacements for some of the technical features. These modifications or replacements still belong to the protection scope of the present invention.

Claims

1. An impact-resistant flame-retardant ABS material, characterized in that: The material is composed of the following raw materials in parts by mass: 67-80 parts of ABS resin, 15-28 parts of intumescent flame retardant, 5-8 parts of toughening agent, 2-5 parts of compatibilizer, and 0.7 parts of processing aid; the intumescent flame retardant is composed of piperazine flame retardant, hypophosphite flame retardant and / or nitrogen flame retardant.

2. The impact-resistant flame-retardant ABS material according to claim 1, characterized in that: The ABS resin is general injection molding grade ABS.

3. The impact-resistant flame-retardant ABS material according to claim 1, characterized in that: The toughening agent is one or two of montmorillonite, low-density polyethylene, chlorinated polyethylene, EVA and calcium stearate.

4. The impact-resistant flame-retardant ABS material according to claim 1, characterized in that: The compatibilizer is POE-g-MAH.

5. The impact-resistant flame-retardant ABS material according to claim 1, characterized in that: The 0.7 parts of processing aids include 0.4 parts of antioxidants and 0.3 parts of anti-dripping agents.

6. The impact-resistant flame-retardant ABS material according to claim 1, characterized in that: The piperazine flame retardant is piperazine pyrophosphate, the hypophosphite flame retardant is aluminum hypophosphite and / or diethyl aluminum hypophosphite, and the nitrogen flame retardant is melamine polyphosphate.

7. The impact-resistant flame-retardant ABS material according to claim 5, characterized in that: The antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], and the anti-dripping agent is polytetrafluoroethylene.

8. The method for preparing an impact-resistant flame-retardant ABS material according to any one of claims 1 to 7, characterized in that: The intumescent flame retardant and toughening agent are mixed evenly after being dried in an oven at 60° C. for 8 hours, and then mixed evenly with ABS resin, compatibilizer and processing aid, and then sent into a screw extruder for melt extrusion, and then injection molding to obtain the impact-resistant flame-retardant ABS material.

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