High-weather-resistance flame-retardant ASA (acrylonitrile-styrene-acrylate) material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of high polymer materials, in particular to a high-weather-resistance flame-retardant ASA material and a preparation method and application thereof.The high-weather-resistance flame-retardant ASA material is prepared from, by weight, 70-80 parts of modified ASA resin, 4-6 parts of flexibilizer, 0.5-1 part of antioxidant and 0.5-1.5 parts of flame retardant. The ASA material prepared by the invention has good weather resistance and flame retardance, excellent mechanical properties and good fluidity, and can be used for preparing films.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to a high weather resistance flame retardant ASA material, a preparation method thereof, and an application thereof. Background Art

[0002] ASA resin is a ternary graft copolymer composed of styrene-acrylonitrile-acrylate. By using acrylate ester rubber instead of conventional polybutadiene rubber, the weather resistance of ASA resin is improved. However, ASA resin is a flammable material, and in some occasions with flame retardant requirements and fire protection grade requirements, ASA often needs to be modified. The most common method is to directly add a large amount of flame retardant. However, the addition of a large amount of ordinary flame retardant will affect the weather resistance of ASA material. Therefore, how to improve the flame retardancy of ASA resin while maintaining good weather resistance has become the research direction of those skilled in the art.

[0003] Patent CN103073809B discloses a high impact high weather resistance environmental bromine-based flame retardant ASA material, which includes the following components: ASA resin, styrene-acrylonitrile resin, environmental bromine-based flame retardant, chlorinated polyethylene, flame retardant synergist. The obtained flame retardant ASA material has excellent weather resistance, and other mechanical properties are balanced. The preparation method is simple. The use of tris(tribromophenyl) cyanurate as a flame retardant in this invention reduces the fluidity of ASA material to a certain extent and is not easy to be made into a film.

[0004] Patent CN110591267B discloses a weather resistance excellent low smoke environmental 5VA grade flame retardant ASA material and a preparation method thereof, which are composed of the following raw materials: ASA resin, CPE resin, brominated epoxy, antimony trioxide, melamine polyphosphate and its derivatives, magnesium hydroxide whiskers, anti-dripping agent, stabilizer, lubricant, hydrotalcite. The process operation of this invention is easy to implement, and the obtained ASA composite material can meet the requirements of the home appliance, automobile, and electronic and electrical industries for product safety. The softening point of the brominated epoxy used in this invention is relatively low, and it is easy to agglomerate during the extrusion process, affecting the production efficiency.

[0005] Therefore, there is an urgent need for an ASA material that is easy to extrude and can be used to prepare a film. Summary of the Invention

[0006] Aiming at the problems existing in the prior art, the purpose of the present invention is to obtain an ASA material with good weather resistance, flame retardancy, excellent mechanical properties, good fluidity and can be used to prepare a film.

[0007] In order to achieve the above purpose, the technical solutions adopted by the present invention are as follows:

[0008] On the one hand, the present invention provides a highly weather-resistant flame-retardant ASA material, which comprises the following raw materials in parts by weight: 55-70 parts of modified ASA resin, 10-20 parts of AS resin, 4-6 parts of toughening agent, 0.5-1 part of antioxidant, and 0.5-1.5 parts of flame retardant.

[0009] In some embodiments, the preparation method of the modified ASA resin comprises the following steps:

[0010] (1) Add PEPA to DMF, stir at 0-5°C for 20-30 min, then add anhydrous potassium carbonate, stir for 3-6 min, then add allyl bromide, continue to stir for 25-35 min, then raise the temperature to 30-35°C, react for 47-49 h, extract, wash, and dry to obtain allylated PEPA;

[0011] (2) Add pentaerythritol triacrylate and emulsifier to deionized water, stir at room temperature for 3-4 h to obtain a pre-emulsion. Take part of the pre-emulsion, raise the temperature to 70-80°C, add initiator under a nitrogen atmosphere, adjust the pH to 9-10, then add the remaining pre-emulsion and initiator, and react for 4-5 h to obtain a reaction solution;

[0012] (3) Add styrene, acrylonitrile, allylated PEPA and emulsifier to deionized water and stir for 3-4 h to obtain a mixed solution. Add the mixed solution to the reaction solution obtained in step (2), react at 70-80°C for 3.5-4.5 h, cool to room temperature, and add anhydrous calcium chloride to obtain the modified ASA resin.

[0013] Preferably, the mass ratio of PEPA to anhydrous potassium carbonate is 1:(2.2-2.6).

[0014] Preferably, the mass ratio of pentaerythritol triacrylate, styrene to acrylonitrile is 1:(1.5-2):(0.6-1).

[0015] In the present invention, by allylating PEPA and then copolymerizing it with styrene, acrylonitrile and pentaerythritol acrylate to obtain the modified ASA resin, the flame retardancy is improved. The possible reasons are, on the one hand, that allylated PEPA is added as a comonomer into the system, and the connection between the phosphate ester groups and the chain segments is tighter, avoiding the problem of the decrease in the weather resistance of the ASA resin caused by poor compatibility or dispersibility when conventional flame retardants are added into the system. On the other hand, the cage-like structure of pentaerythritol phosphate PEPA increases the interaction between the modified ASA resin and the toughening agent and other additives, further increasing the binding between molecules and increasing the weather resistance and mechanical properties of the ASA material.

[0016] In some embodiments, the mass ratio of PEPA to allyl bromide is 1:(0.7-1).

[0017] By limiting the mass ratio of PEPA to allyl bromide, the present invention avoids the problem that insufficient addition of allyl bromide reduces the number of double bonds, affects copolymerization, and thus affects the flame retardancy of the modified ASA resin. In addition, it avoids the influence of excessive bromine content in the modified ASA resin on the generation of harmful gases.

[0018] In some embodiments, the mass ratio of pentaerythritol triacrylate to allylated PEPA is 1:(0.4 - 0.8).

[0019] By limiting the mass ratios of pentaerythritol triacrylate, styrene, acrylonitrile, and allylated PEPA, the present invention increases the flame retardancy of the modified ASA resin while avoiding a decrease in toughness and fluidity that would affect film formation.

[0020] In some embodiments, the method for preparing the flame retardant comprises the following steps: adding hydrotalcite and KH570 silane coupling agent to absolute ethanol, reacting at 70 - 80 °C for 5 - 6 h, then adding 2-hydroxy-4-acryloyloxy benzophenone, vinyl silicone oil, and azobisisobutyronitrile, reacting at 70 - 80 °C for 1 - 2 h, and performing rotary evaporation to obtain the flame retardant.

[0021] The flame retardant effect of hydrotalcite is stable, harmless to humans and the environment, and has a reinforcing effect on ASA materials. By modifying hydrotalcite with KH570 silane coupling agent and copolymerizing it with 2-hydroxy-4-acryloyloxy benzophenone and vinyl silicone oil, the present invention improves the dispersibility of hydrotalcite in the system and increases the weather resistance of ASA materials. The possible reason is that 2-hydroxy-4-acryloyloxy benzophenone increases the ultraviolet resistance of ASA materials, and the steric hindrance of the benzene ring weakens the hydrogen bond between hydroxyl groups, enhancing the dispersibility of hydrotalcite. In addition, hydrotalcite can absorb hydrogen chloride gas generated by chlorinated polyethylene during the extrusion process, reducing the emission of harmful gases and the harm to the human body; vinyl silicone oil increases the lubricity of ASA materials and improves processability.

[0022] In some embodiments, the mass ratio of hydrotalcite, 2-hydroxy-4-acryloyloxy benzophenone, and vinyl silicone oil is 1:(0.5 - 1):(0.7 - 1).

[0023] By limiting the mass ratios of hydrotalcite, 2-hydroxy-4-acryloyloxy benzophenone, and vinyl silicone oil, the present invention increases the dispersibility and ultraviolet resistance of ASA materials while avoiding the problem of increased brittleness of ASA materials due to the presence of a large number of benzene ring structures in the system.

[0024] In some embodiments, the particle size of the flame retardant is 0.6 - 2 μm.

[0025] In some embodiments, the toughening agent is chlorinated polyethylene resin.

[0026] The second aspect of the present invention provides a method for preparing a highly weather-resistant flame-retardant ASA material, comprising the following steps: mixing and stirring a modified ASA resin, an AS resin, a toughening agent, an antioxidant, and a flame retardant for 30 - 50 min, then adding them into a twin-screw extruder, controlling the temperature at 200 - 220 °C and the rotation speed at 400 - 600 rpm, extruding and pelletizing, and drying to obtain the highly weather-resistant flame-retardant ASA material.

[0027] The third aspect of the present invention provides an application of the highly weather-resistant flame-retardant ASA material in the preparation of films.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) By using a modified ASA resin in combination with other additives, the present invention obtains an ASA material that can be used for preparing films, which has good mechanical properties, flame retardancy, weather resistance, and fluidity.

[0030] (2) In the present invention, PEPA is allylated and then copolymerized with styrene, acrylonitrile, and pentaerythritol acrylate to obtain a modified ASA resin, which improves the flame retardancy. The allylation of PEPA as a comonomer in the system makes the connection between the phosphate ester groups and the segments closer, avoiding the problem of the decrease in the weather resistance of the ASA resin caused by poor compatibility or dispersibility of conventional flame retardants in the system. On the other hand, the cage-like structure of pentaerythritol phosphate PEPA increases the interaction between the modified ASA resin, the toughening agent, and other additives, further increasing the binding between molecules and enhancing the weather resistance and mechanical properties of the ASA material.

[0031] (3) In the present invention, hydrotalcite is modified with KH570 silane coupling agent and then copolymerized with 2-hydroxy-4-acryloyloxy benzophenone and vinyl silicone oil, which improves the dispersibility of hydrotalcite in the system and increases the weather resistance of the ASA material. In addition, hydrotalcite can absorb hydrogen chloride gas generated by chlorinated polyethylene during the extrusion process, reducing the emission of harmful gases and the harm to the human body; vinyl silicone oil increases the lubricity and processability of the ASA material. Specific Embodiments

[0032] The following will illustrate the present invention in combination with specific embodiments. It should be noted that the following examples are examples of the present invention, only used to illustrate the present invention, and not to limit the present invention. Other combinations and various improvements within the concept of the present invention can be made without departing from the main idea or scope of the present invention.

[0033] In the following examples and comparative examples, the compounds and related reagents used are all commercially available. Among them, the hydrotalcite was purchased from Kaisima (Dandong) High-Tech Materials Technology Co., Ltd., with an average particle size of 0.6 μm; the chlorinated polyethylene was purchased from Shouguang Hongchuang Environmental Protection Technology Co., Ltd., with a chlorine content of 35 ± 2%; the AS resin was purchased from Dongguan Hongkuo Plastic Co., Ltd., with the model NF2200; the vinyl silicone oil was purchased from Wuhan Linsheng Technology Co., Ltd., with a viscosity of 1000 mPa·s (25 °C).

[0034] Preparation Example 1

[0035] The preparation method of modified ASA resin-1 includes the following steps:

[0036] (1) Add 10 g of PEPA to 50 ml of DMF, stir at 3 °C for 25 min, then add 24 g of anhydrous potassium carbonate, stir for 5 min, then add 8 g of allyl bromide, continue to stir for 30 min, then raise the temperature to 32 °C, react for 48 h, extract, wash, and dry to obtain allylated PEPA;

[0037] (2) Add 10 g of pentaerythritol triacrylate and 0.6 g of SDS to 50 ml of deionized water, stir at room temperature for 3.5 h to obtain a pre-emulsion. Take 3.5 g of the pre-emulsion, raise the temperature to 75 °C, add 0.01 g of potassium persulfate under a nitrogen atmosphere, and adjust the pH to 9 with 70 wt% sodium hydroxide solution. Then add the remaining pre-emulsion and 0.1 g of potassium persulfate, and react for 4.5 h to obtain a reaction solution;

[0038] (3) Add 18 g of styrene, 8 g of acrylonitrile, 6 g of allylated PEPA, and 0.2 g of SDS to 100 ml of deionized water and stir for 3.5 h to obtain a mixture. Add the mixture to the entire reaction solution obtained in step (2) in two equal portions, react at 75 °C for 4 h, cool to room temperature, add 0.1 g of anhydrous calcium chloride, filter, wash, and dry to obtain modified ASA resin-1.

[0039] Preparation Example 2

[0040] The preparation method of modified ASA resin-2 is the same as that of Preparation Example 1, except that the addition amount of allyl bromide is 5 g.

[0041] Preparation Example 3

[0042] The preparation method of modified ASA resin-3 is the same as that of Preparation Example 1, except that the addition amount of allylated PEPA is 12 g.

[0043] Preparation Example 4

[0044] The preparation method of AS resin includes the following steps:

[0045] (1) Add 10 g of pentaerythritol triacrylate and 0.6 g of SDS to 50 ml of deionized water, stir at room temperature for 3.5 h to obtain a pre-emulsion. Take 3.5 g of the pre-emulsion, heat it to 75 °C, add 0.01 g of potassium persulfate under a nitrogen atmosphere, and adjust the pH to 9 with 70 wt% sodium hydroxide solution. Then add the remaining pre-emulsion and 0.1 g of potassium persulfate, and react for 4.5 h to obtain a reaction solution;

[0046] (2) Add 18 g of styrene, 8 g of acrylonitrile and 0.2 g of SDS to 100 ml of deionized water and stir for 3.5 h to obtain a mixed solution. Add the mixed solution to the entire reaction solution obtained in step (1) in two equal portions, react at 75 °C for 4 h, cool to room temperature, add 0.1 g of anhydrous calcium chloride, filter, wash and dry to obtain the ASA resin.

[0047] Preparation Example 5

[0048] A preparation method of flame retardant - 1, comprising the following steps: Add 10 g of hydrotalcite and 8 g of KH570 silane coupling agent to 100 ml of absolute ethanol, react at 75 °C for 5.5 h, then add 8 g of 2-hydroxy-4-acryloyloxy benzophenone, 9 g of vinyl silicone oil and 0.1 g of azobisisobutyronitrile, react at 75 °C for 1.5 h, and perform rotary evaporation to obtain flame retardant - 1.

[0049] Preparation Example 6

[0050] A preparation method of flame retardant - 2, the specific implementation method is the same as that of Preparation Example 5, the difference is that the addition amount of 2-hydroxy-4-acryloyloxy benzophenone is 12 g.

[0051] Preparation Example 7

[0052] A preparation method of flame retardant - 3, the specific implementation method is the same as that of Preparation Example 5, the difference is that the addition amount of vinyl silicone oil is 5 g.

[0053] Example 1

[0054] A highly weather-resistant flame-retardant ASA material, by weight, comprises the following raw materials: 75 parts of modified ASA resin - 1, 15 parts of AS resin, 5 parts of chlorinated polyethylene, 0.8 part of antioxidant 1010, 1 part of flame retardant - 1.

[0055] The preparation method of the highly weather-resistant flame-retardant ASA material in this example comprises the following steps: Mix and stir modified ASA resin - 1, AS resin, chlorinated polyethylene, antioxidant 1010 and flame retardant - 1 for 40 min, then add them into a twin-screw extruder, control the temperature at 210 °C and the rotation speed at 500 rpm, extrude and pelletize, and dry to obtain the highly weather-resistant flame-retardant ASA material.

[0056] Example 2

[0057] A highly weather-resistant flame-retardant ASA material, by weight, comprises the following raw materials: 70 parts of modified ASA resin-1, 10 parts of AS resin, 4 parts of chlorinated polyethylene, 0.5 part of antioxidant 1010, and 0.5 part of flame retardant-1.

[0058] The preparation method of the highly weather-resistant flame-retardant ASA material in this example comprises the following steps: Mix and stir the modified ASA resin-1, AS resin, chlorinated polyethylene, antioxidant 1010, and flame retardant-1 for 30 min, then add them into a twin-screw extruder, control the temperature at 200 °C, the rotation speed at 400 rpm, extrude and pelletize, and dry to obtain the highly weather-resistant flame-retardant ASA material.

[0059] Example 3

[0060] A highly weather-resistant flame-retardant ASA material, by weight, comprises the following raw materials: 80 parts of modified ASA resin-1, 20 parts of AS resin, 6 parts of chlorinated polyethylene, 1 part of antioxidant 1010, and 1.5 parts of flame retardant-1.

[0061] The preparation method of the highly weather-resistant flame-retardant ASA material in this example comprises the following steps: Mix and stir the modified ASA resin-1, AS resin, chlorinated polyethylene, antioxidant 1010, and flame retardant-1 for 50 min, then add them into a twin-screw extruder, control the temperature at 220 °C, the rotation speed at 600 rpm, extrude and pelletize, and dry to obtain the highly weather-resistant flame-retardant ASA material.

[0062] Example 4

[0063] A highly weather-resistant flame-retardant ASA material and its preparation method, the specific implementation method is the same as that of Example 1, the difference is that the modified ASA resin-1 is replaced with the modified ASA resin-2 in equal amount.

[0064] Example 5

[0065] A highly weather-resistant flame-retardant ASA material and its preparation method, the specific implementation method is the same as that of Example 1, the difference is that the modified ASA resin-1 is replaced with the modified ASA resin-3 in equal amount.

[0066] Example 6

[0067] A highly weather-resistant flame-retardant ASA material and its preparation method, the specific implementation method is the same as that of Example 1, the difference is that the flame retardant-1 is replaced with the flame retardant-2 in equal amount.

[0068] Example 7

[0069] A highly weather-resistant flame-retardant ASA material and its preparation method. The specific implementation manner is the same as that of Example 1, except that the flame retardant -1 is replaced with the flame retardant -3 in equal amounts.

[0070] Example 8

[0071] A highly weather-resistant flame-retardant ASA material and its preparation method. The specific implementation manner is the same as that of Example 1, except that the flame retardant -1 is replaced with hydrotalcite in equal amounts.

[0072] Comparative Example 1

[0073] A highly weather-resistant flame-retardant ASA material and its preparation method. The specific implementation manner is the same as that of Example 1, except that the modified ASA resin -1 is replaced with ASA resin in equal amounts.

[0074] Performance testing

[0075] The following tests were carried out on the highly weather-resistant flame-retardant ASA materials obtained in the above examples and comparative examples:

[0076] 1. Mechanical properties

[0077] The tensile strength was tested according to the ISO527 standard. The specimen size was 150 mm × 10 mm × 4 mm, and the tensile speed was 50 mm / min; the flexural strength was tested according to the ISO178 standard. The specimen size was 80 mm × 10 mm × 4 mm, the tensile speed was 2 mm / min, and the span was 64 mm.

[0078] 2. Flame retardancy

[0079] The test was carried out according to the UL-94 standard.

[0080] 3. Weather resistance

[0081] The xenon lamp aging was carried out for 5000 h according to the GB / T16422.2 standard, and it was judged that the weather resistance was good when ΔE ≤ 2.0.

[0082] The test results are shown in Table 1:

[0083] Table 1

[0084]

[0085]

[0086] From the comparison of the experimental data in Examples 1-3 in Table 1, it can be seen that the ASA material obtained by the present invention has good mechanical properties, flame retardancy and weather resistance; from the comparison between Example 4 and Example 1, it can be seen that the change in the ratio of PEPA to allyl bromide affects the occurrence of the copolymerization reaction, resulting in a decrease in the mechanical properties and flame retardancy of the ASA material; from the comparison between Example 5 and Example 1, it can be seen that the change in the ratio of pentaerythritol triacrylate, styrene, acrylonitrile to allylated PEPA may affect the crosslinking degree of the modified ASA resin, resulting in a decrease in the mechanical properties of the ASA material; from the comparison between Examples 6 and 7 and Example 1, it can be seen that the change in the ratio of hydrotalcite, 2-hydroxy-4-acryloyloxy benzophenone and vinyl silicone oil results in changes in all properties of the ASA material; from the comparison between Example 8 and Example 1, it can be seen that the direct use of hydrotalcite has poor dispersibility, and the mechanical properties and weather resistance of the ASA material both decrease; from the comparison between Comparative Example 1 and Example 1, it can be seen that the direct use of ASA resin results in a decrease in the mechanical properties and flame retardancy of the ASA material.

[0087] The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it. It cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A highly weather-resistant flame-retardant ASA material, characterized in that: The invention comprises the following raw materials in parts by weight: 55-70 parts of modified ASA resin, 10-20 parts of AS resin, 4-6 parts of toughening agent, 0.5-1 parts of antioxidant and 0.5-1.5 parts of flame retardant.

2. The highly weather-resistant flame-retardant ASA material according to claim 1, characterized in that: The preparation method of the modified ASA resin comprises the following steps: (1) PEPA is added to DMF, stirred at 0-5°C for 20-30 minutes, then anhydrous potassium carbonate is added, stirred for 3-6 minutes, then allyl bromide is added, and stirring is continued for 25-35 minutes, then the temperature is raised to 30-35°C, reacted for 47-49 hours, extracted, washed, and dried to obtain allylated PEPA; (2) adding pentaerythritol triacrylate and an emulsifier to deionized water, stirring at room temperature for 3-4 hours to obtain a pre-emulsion, taking a portion of the pre-emulsion, heating it to 70-80° C., adding an initiator under a nitrogen atmosphere, and adjusting the pH to 9-10, then adding the remaining pre-emulsion and initiator, reacting for 4-5 hours, and obtaining a reaction solution; (3) Add styrene, acrylonitrile, allylated PEPA and an emulsifier into deionized water and stir for 3-4 hours to obtain a mixed solution, add the mixed solution to the reaction solution obtained in step (2), react at 70-80° C. for 3.5-4.5 hours, cool to room temperature, add anhydrous calcium chloride, and obtain a modified ASA resin.

3. The highly weather-resistant flame-retardant ASA material according to claim 2, characterized in that: The mass ratio of PEPA to allyl bromide is 1:(0.7-1).

4. The highly weather-resistant flame-retardant ASA material according to claim 2, characterized in that: The mass ratio of the pentaerythritol triacrylate to the allylated PEPA is 1:(0.4-0.8).

5. The highly weather-resistant flame-retardant ASA material according to claim 1, characterized in that: The preparation method of the flame retardant comprises the following steps: adding hydrotalcite and KH570 silane coupling agent into anhydrous ethanol, reacting at 70-80°C for 5-6h, then adding 2-hydroxy-4-acryloxybenzophenone, vinyl silicone oil and azobisisobutyronitrile, reacting at 70-80°C for 1-2h, and rotary evaporating to obtain the flame retardant.

6. The highly weather-resistant flame-retardant ASA material according to claim 5, characterized in that: The mass ratio of the hydrotalcite, 2-hydroxy-4-acryloxybenzophenone and vinyl silicone oil is 1:(0.5-1):(0.7-1).

7. The highly weather-resistant flame-retardant ASA material according to claim 5, characterized in that: The particle size of the flame retardant is 0.6-2 μm.

8. The highly weather-resistant flame-retardant ASA material according to claim 1, characterized in that: The toughening agent is chlorinated polyethylene resin.

9. A method for preparing the highly weather-resistant flame-retardant ASA material according to claims 1-8, characterized in that: The following steps are involved: The modified ASA resin, AS resin, toughening agent, antioxidant and flame retardant are mixed and stirred for 30-50 minutes, then added into a twin-screw extruder, the temperature is controlled at 200-220°C, the rotation speed is 400-600rpm, extruded into granules, and dried to obtain a highly weather-resistant flame-retardant ASA material.

10. Use of the highly weather-resistant flame-retardant ASA material according to any one of claims 1 to 8 or the highly weather-resistant flame-retardant ASA material obtained by the preparation method according to claim 9 in preparing films.

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