High-strength flame-retardant PC / ABS alloy and preparation method thereof

Abstract

The invention relates to the technical field of alloy preparation, and discloses a high-strength flame-retardant PC / ABS alloy and a preparation method thereof.The high-strength flame-retardant PC / ABS alloy is prepared from, by weight, 70 parts of PC resin, 30 parts of ABS resin, 10-20 parts of modified ABS, 5-10 parts of modified graphene and 0.1-0.4 part of antioxidants, the modified ABS and the modified graphene are prepared and introduced into the alloy, and therefore the high-strength flame-retardant PC / ABS alloy is obtained. The flame retardant property, the mechanical property and the thermal stability of the PC / ABS alloy are improved, and the application range of the PC / ABS alloy is widened.

Description

Technical Field

[0001] The invention relates to the technical field of alloy preparation, in particular to a high-strength flame-retardant PC / ABS alloy and a preparation method thereof. Background Art

[0002] The macromolecular chain structure of polycarbonate (PC) contains both flexible carbonate chains and rigid benzene ring structures, so it has the advantages of high impact strength, good dimensional stability, and heat resistance. However, its stress resistance is poor and its notch sensitivity is high, which limits its application range. Acrylonitrile-butadiene-styrene copolymer (ABS) has good impact resistance and processing fluidity, and is widely used in the automotive, electrical, and machinery fields, but its heat resistance and weather resistance are poor.

[0003] PC / ABS alloy is a commonly used engineering plastic alloy with good mechanical properties, processing fluidity and heat resistance. It is widely used in business machinery, household appliances, communication equipment and other fields. However, the limiting oxygen index of PC is 25%, and the limiting oxygen index of ABS is 18%. PC / ABS alloy does not pass the UL-94 vertical combustion V-2 grade. When the flammable PC / ABS alloy encounters a fire, it will cause loss of life and property. In addition, the application fields of PC / ABS alloy have higher flame retardant requirements for it.

[0004] For example, the Chinese patent authorization announcement number is CN 112724627 B, which discloses PC / ABS alloy materials and their applications. The invention uses PC, ABS, toughening agents, flame retardants, etc. as raw materials to prepare a PC / ABS alloy material. The prepared alloy material has good mechanical properties and flame retardant properties, but does not improve the thermal stability of the alloy. Summary of the invention

[0005] 1. Technical issues to be resolved In view of the deficiencies in the prior art, the present invention provides a high-strength flame-retardant PC / ABS alloy and a preparation method thereof. The prepared PC / ABS alloy has high strength, excellent flame retardancy and thermal stability.

[0006] (II) Technical solution A high-strength flame-retardant PC / ABS alloy, the high-strength flame-retardant PC / ABS alloy is composed of the following raw materials in parts by weight: 70 parts of PC resin, 30 parts of ABS resin, 10-20 parts of modified ABS, 5-10 parts of modified graphene, and 0.1-0.4 parts of antioxidant; The preparation method of the high-strength flame-retardant PC / ABS alloy comprises the following steps: S1. Add intermediate product A to 1,2-dichloroethane, stir evenly, add intermediate product C and triethylamine, control the temperature to 60-70°C, react for 8-12h, filter after the reaction, and distill under reduced pressure to obtain hexenyl borate, wherein the mass ratio of intermediate product A, intermediate product C, and triethylamine is 2.2-2.5:1:0.8-1. In this reaction, the chlorine atom contained in intermediate product A is substituted with the phenolic hydroxyl group in intermediate product C to obtain hexenyl borate. In intermediate product C, not only the synergistic flame retardant element phosphorus is introduced, but also the hexenyl structure is introduced. The reaction route is: , where R is ; S2. Add graphene oxide and intermediate product C to N,N-dimethylformamide solvent, stir and disperse, then add 1-ethyl (-3-dimethylaminopropyl) carbodiimide (EDC), use argon as reaction protection gas, control the temperature to 100-110°C, react for 8-12h, centrifuge after the reaction, wash with deionized water, and dry to obtain modified graphene, wherein the mass ratio of graphene oxide to intermediate product C is 1:3-5. In this reaction, the hydroxyl group contained in the intermediate product C reacts with the carboxyl group contained on the surface of graphene oxide to form a chemical bond, which can disperse graphene oxide, reduce the agglomeration degree of graphene oxide, and enhance its dispersibility in the material. The reaction route is: ; S3, adding ABS resin to butyl acetate, stirring and dissolving at 80°C, adding dicumyl peroxide, maleic anhydride and hexenyl borate thereto, reacting for 8-12h under nitrogen protection, cooling to room temperature after the reaction, adding ethanol thereto, filtering, washing with ethanol, extracting and drying to obtain modified ABS, wherein the mass ratio of ABS resin, dicumyl peroxide, maleic anhydride and hexenyl borate is 100:2-4:10-15:5-10, using dicumyl peroxide as an initiator, maleic anhydride and hexenyl borate as grafting monomers, and grafting the two into ABS to obtain modified A BS, in this reaction, the alkenyl structure contained in maleic anhydride and hexenyl borate is polymerized with the alkenyl structure contained in ABS. On the one hand, since hexenyl borate contains hexenyl structure, the prepared modified ABS contains more chemical crosslinking sites, which can be introduced into the material to increase the mechanical properties of the material. On the other hand, the ABS in the modified ABS graft and the ABS in the alloy can be fully compatible, and the MAH monomer contained in the modified ABS can be transesterified with the terminal phenolic hydroxyl group in PC to generate chemical links, thereby increasing the compatibility of ABS and PC. S4. Add dried PC resin, ABS resin, modified ABS, modified graphene and antioxidant into a twin-screw extruder for melt extrusion, cool and granulate, and then place in an injection molding machine for injection molding to obtain a high-strength flame-retardant PC / ABS alloy, wherein the mass ratio of PC to ABS is 7:3, PC is the main phase, and ABS is the dispersed phase dispersed in the PC main phase.

[0007] Preferably, in S1, the method for preparing the intermediate product A comprises the following steps: Phosphorus oxychloride is added to 1,2-dichloroethane, nitrogen is introduced, magnetic stirring is performed, and then p-hydroxystyrene and triethylamine are added thereto. The reaction is stirred at room temperature for 1-2 hours, and the temperature is raised to 55-65°C and the reaction is performed for 10-14 hours. After the reaction is completed, suction filtration is performed and vacuum distillation is performed to obtain an intermediate product A, wherein the mass ratio of phosphorus oxychloride, p-hydroxystyrene and triethylamine is 1:1.5-1.6:1.8-2.2, and the reaction route is: ; Preferably, in S1, the preparation method of the intermediate product C comprises the following steps: SS1. Add p-hydroxybenzaldehyde and boric acid to toluene, first heat to 100°C, react for 1-2h, then heat to 120-130°C, react for 3-4h, continue to heat to 150-160°C, react for 4-6h, and after the reaction, distill under reduced pressure and dry to obtain intermediate product B, wherein the mass ratio of p-hydroxybenzaldehyde to boric acid is 10-14:1. In this reaction, the phenolic hydroxyl group in p-hydroxybenzaldehyde is dehydrated with boric acid to obtain intermediate product B. Organic boric acid ester is easily hydrolyzed. The present invention introduces a benzene ring structure around boric acid. The benzene ring can provide steric hindrance, shield boron atoms, hinder water molecules from approaching, improve stability, and reduce the hydrolysis effect. The reaction route is: ; SS2. Add p-aminophenol to ethanol, stir and disperse, then add intermediate product B, control the temperature to 30-40°C, add formic acid, react for 4-6h, wash with ether after the reaction, filter, and dry to obtain intermediate product C, wherein the mass ratio of p-aminophenol to intermediate product B is 1.8-2:1. In this reaction, the amino group in p-aminophenol and the aldehyde group in intermediate product B are used to carry out Schiff base condensation reaction to obtain intermediate product C. A heat-resistant Schiff base structure is introduced into intermediate product C. When heated, the Schiff base structure can produce a cross-linked network structure, which synergistically improves the heat resistance of the material with the heat-resistant benzene ring structure. The reaction route is: .

[0008] 3. Beneficial technical effects The graphene used in the present invention is easy to agglomerate itself, and it is modified so that the material and the graphene form a chemical bond, thereby solving the problem that the graphene is difficult to disperse evenly in the material. The graphene has high compatibility in the material and can be evenly dispersed in the material. On the one hand, when subjected to external stress, it can absorb stress energy and improve the mechanical properties of the material. On the other hand, as inorganic nanoparticles, it can cooperate with the heat-resistant Schiff base structure and the rigid benzene ring structure to improve the heat resistance of the material. On the other hand, the inorganic graphene oxide has a unique two-dimensional layered structure, so that a dense and continuous carbon layer can be formed during the degradation process, thereby preventing heat transfer and delaying degradation, and forming an inorganic flame retardant system.

[0009] The alloy prepared by the present invention contains organic phosphorus, organic nitrogen and organic boron. The organic phosphorus will first be decomposed by heat to generate polyphosphoric acid, which will promote the rapid dehydration and carbonization of the substrate and play a flame retardant role in the condensed phase. The organic nitrogen will be decomposed by heat to generate NH 3 、N 2 Incombustible gases such as nitrogen, phosphorus and boron dilute the oxygen concentration and play a flame retardant role in the gas phase. At the same time, the gas can act on the carbon layer generated by organic phosphorus and increase its area when escaping, exerting a synergistic effect between the condensed phase and the gas phase; organic boron produces boric acid during the combustion process, which forms a glass-like melt covering the surface of the material when cracked, forming a glass-like protective layer, which not only reduces the further oxidation of the carbon layer, but also prevents the escape of volatile combustibles, and plays a gas phase and condensed phase flame retardant effect at the same time. Nitrogen, phosphorus and boron form an organic flame retardant system. Together with the inorganic flame retardant system, an organic-inorganic synergistic flame retardant system is formed to jointly improve the flame retardant properties of the alloy. In addition, the alloy material prepared by the present invention contains a large number of branched structures, which can be intertwined to produce physical cross-linking sites. When subjected to external stress, the stress can be dispersed to other molecular chains through the cross-linking sites, thereby synergizing with graphene to improve the mechanical properties of the material. DETAILED DESCRIPTION

[0010] Preparation method of graphene oxide: add 46mL concentrated sulfuric acid, 1g sodium nitrate, and 2g graphite into a beaker, control the temperature at 10°C, add 6g potassium permanganate and react for 1h, heat to 35°C, react for 2h, add 96mL deionized water, heat to 95°C, react for 30min, then add 30% hydrogen peroxide by mass until the solution turns bright yellow, filter, wash with deionized water until neutral, centrifuge, and dry to obtain graphene oxide. Embodiment 1

[0011] (1) Add 1 g of phosphorus oxychloride to 1,2-dichloroethane, introduce nitrogen, and stir magnetically. Then add 1.5 g of p-hydroxystyrene and 1.8 g of triethylamine. Stir and react at room temperature for 2 h. Raise the temperature to 60 °C and react for 12 h. After the reaction is completed, filter and distill under reduced pressure to obtain intermediate product A.

[0012] (2) Add 10 g of p-hydroxybenzaldehyde and 1 g of boric acid to toluene, first heat to 100 °C, react for 2 h, then heat to 130 °C, react for 3 h, and continue to heat to 160 °C, react for 4 h. After the reaction is completed, distill under reduced pressure and dry to obtain intermediate product B.

[0013] (3) Add 20 g of p-aminophenol to ethanol, stir and disperse, then add 10 g of intermediate product B, control the temperature to 30°C, add 12 mL of formic acid, and react for 6 hours. After the reaction is completed, wash with ether, filter, and dry to obtain intermediate product C.

[0014] (4) Add 2.2 g of intermediate product A to 1,2-dichloroethane and stir evenly. Add 1 g of intermediate product C and 1 g of triethylamine. Control the temperature to 65 °C and react for 12 h. After the reaction is completed, filter and distill under reduced pressure to obtain hexaenyl borate.

[0015] (5) Add 10 g of graphene oxide and 50 g of intermediate product C into N,N-dimethylformamide solvent, stir and disperse, then add 10 mL of EDC, use argon as the reaction protective gas, control the temperature to 110 ° C, react for 8 h, and after the reaction is completed, centrifuge, wash with deionized water, and dry to obtain modified graphene.

[0016] (6) Add 20 g of ABS resin to butyl acetate, stir and dissolve at 80°C, add 0.4 g of diisopropylbenzene peroxide, 3 g of maleic anhydride and 1 g of hexenyl borate, and react for 10 h under nitrogen protection. After the reaction is completed, cool to room temperature, add ethanol, filter, wash with ethanol, extract and dry to obtain modified ABS.

[0017] (7) Add 70g of dried PC resin, 30g of ABS resin, 10g of modified ABS, 5g of modified graphene, and 0.1g of antioxidant 1010 to a twin-screw extruder for melt extrusion. The temperatures of each section of the twin-screw extruder are 220°C, 230°C, 240°C, and 245°C, the head temperature is 250°C, and the screw speed is 100r / min. Cool and granulate, then place in an injection molding machine for injection molding. The injection molding temperatures of the injection molding machine are 180°C, 245°C, 250°C, and 255°C, and the injection molding pressure is 55MPa to obtain a high-strength flame-retardant PC / ABS alloy. Embodiment 2

[0018] (1) Add 1 g of phosphorus oxychloride to 1,2-dichloroethane, introduce nitrogen, and stir magnetically. Then add 1.6 g of p-hydroxystyrene and 2.2 g of triethylamine. Stir and react at room temperature for 1 h. Raise the temperature to 65 °C and react for 10 h. After the reaction is completed, filter and distill under reduced pressure to obtain intermediate product A.

[0019] (2) Add 14 g of p-hydroxybenzaldehyde and 1 g of boric acid to toluene, first heat to 100 °C, react for 1 h, then heat to 120 °C, react for 4 h, and continue to heat to 155 °C, react for 5 h. After the reaction is completed, distill under reduced pressure and dry to obtain intermediate product B.

[0020] (3) Add 19 g of p-aminophenol to ethanol, stir and disperse, then add 10 g of intermediate product B, control the temperature to 40°C, add 12 mL of formic acid, and react for 4 h. After the reaction is completed, wash with ether, filter, and dry to obtain intermediate product C.

[0021] (4) Add 2.5 g of intermediate product A to 1,2-dichloroethane and stir evenly. Then add 1 g of intermediate product C and 0.8 g of triethylamine. Control the temperature to 60°C and react for 10 h. After the reaction is completed, filter and distill under reduced pressure to obtain hexaenyl borate.

[0022] (5) Add 10 g of graphene oxide and 30 g of intermediate product C to N,N-dimethylformamide solvent, stir and disperse, then add 10 mL of EDC, use argon as the reaction protective gas, control the temperature to 105 °C, react for 12 h, and after the reaction is completed, centrifuge, wash with deionized water, and dry to obtain modified graphene.

[0023] (6) Add 20 g of ABS resin to butyl acetate, stir and dissolve at 80°C, add 0.5 g of diisopropylbenzene peroxide, 3 g of maleic anhydride and 1 g of hexenyl borate, and react for 12 h under nitrogen protection. After the reaction is completed, cool to room temperature, add ethanol, filter, wash with ethanol, extract and dry to obtain modified ABS.

[0024] (7) Add 70g of dried PC resin, 30g of ABS resin, 15g of modified ABS, 8g of modified graphene, and 0.3g of antioxidant 1010 to a twin-screw extruder for melt extrusion. The temperatures of each section of the twin-screw extruder are 220°C, 230°C, 240°C, and 245°C, the head temperature is 250°C, and the screw speed is 100r / min. Cool and granulate, then place in an injection molding machine for injection molding. The injection molding temperatures of the injection molding machine are 180°C, 245°C, 250°C, and 255°C, and the injection molding pressure is 55MPa to obtain a high-strength flame-retardant PC / ABS alloy. Embodiment 3

[0025] (1) Add 1 g of phosphorus oxychloride to 1,2-dichloroethane, introduce nitrogen, and stir magnetically. Then add 1.6 g of p-hydroxystyrene and 2 g of triethylamine. Stir and react at room temperature for 2 h. Heat to 55 °C and react for 14 h. After the reaction is completed, filter and distill under reduced pressure to obtain intermediate product A.

[0026] (2) Add 13 g of p-hydroxybenzaldehyde and 1 g of boric acid to toluene, first heat to 100 °C, react for 1 h, then heat to 125 °C, react for 3 h, and continue to heat to 150 °C, react for 6 h. After the reaction is completed, distill under reduced pressure and dry to obtain intermediate product B.

[0027] (3) Add 18 g of p-aminophenol to ethanol, stir and disperse, then add 10 g of intermediate product B, control the temperature to 35°C, add 12 mL of formic acid, react for 6 h, and after the reaction is completed, wash with ether, filter, and dry to obtain intermediate product C.

[0028] (4) Add 2.4 g of intermediate product A to 1,2-dichloroethane and stir evenly. Then add 1 g of intermediate product C and 0.9 g of triethylamine. Control the temperature to 70°C and react for 8 h. After the reaction is completed, filter and distill under reduced pressure to obtain hexaenyl borate.

[0029] (5) Add 10 g of graphene oxide and 40 g of intermediate product C to N,N-dimethylformamide solvent, stir and disperse, then add 10 mL of EDC, use argon as the reaction protective gas, control the temperature to 100 °C, react for 10 h, and after the reaction is completed, centrifuge, wash with deionized water, and dry to obtain modified graphene.

[0030] (6) Add 20 g of ABS resin to butyl acetate, stir and dissolve at 80°C, add 0.8 g of diisopropylbenzene peroxide, 2 g of maleic anhydride and 2 g of hexenyl borate, and react for 8 h under nitrogen protection. After the reaction is completed, cool to room temperature, add ethanol, filter, wash with ethanol, extract and dry to obtain modified ABS.

[0031] (7) 70g of dried PC resin, 30g of ABS resin, 20g of modified ABS, 10g of modified graphene, and 0.4g of antioxidant 1010 were added to a twin-screw extruder for melt extrusion. The temperatures of each section of the twin-screw extruder were 220°C, 230°C, 240°C, and 245°C, the head temperature was 250°C, and the screw speed was 100r / min. After cooling and granulation, the pellets were placed in an injection molding machine for injection molding. The injection molding temperatures of the injection molding machine were 180°C, 245°C, 250°C, and 255°C, and the injection molding pressure was 55MPa to obtain a high-strength flame-retardant PC / ABS alloy.

[0032] Comparative Example 1 The difference between this comparative example and Example 1 is that modified ABS is not contained in step (7).

[0033] Comparative Example 2 The difference between this comparative example and Example 1 is that step (7) does not contain modified graphene.

[0034] Use an oxygen index meter to test the oxygen index of a material.

[0035] Use a horizontal vertical combustion test chamber to test the vertical combustion level of the material.

[0036] Table 1:

[0037] It can be seen from the above table that the alloy material prepared by the present invention has good flame retardant properties.

[0038] The tensile properties of the material were tested using a universal material testing machine at a tensile rate of 50 mm / min.

[0039] The notched impact strength of the material was tested using a pendulum impact tester.

[0040] Table 2:

[0041] It can be seen from the table that the material prepared by the present invention has good mechanical properties.

[0042] According to ISO75-1-2013 standard, the heat deformation temperature is tested under the conditions of 1.80MPa load and 120℃ / h heating rate.

[0043] Table 3:

[0044] The higher the heat deformation temperature, the higher the thermal stability. It can be seen from the table that the material prepared by the present invention has higher heat resistance stability.

Claims

1. A high-strength flame-retardant PC / ABS alloy, characterized in that: The high-strength flame-retardant PC / ABS alloy is composed of the following raw materials in parts by weight: 70 parts of PC resin, 30 parts of ABS resin, 10-20 parts of modified ABS, 5-10 parts of modified graphene, and 0.1-0.4 parts of antioxidant; The preparation method of the high-strength flame-retardant PC / ABS alloy comprises the following steps: S1. Add the intermediate product A to 1,2-dichloroethane, stir evenly, add the intermediate product C and triethylamine, control the temperature to 60-70°C, react for 8-12h, and after the reaction is completed, filter and distill under reduced pressure to obtain hexaenyl borate; S2, adding graphene oxide and intermediate product C to N,N-dimethylformamide solvent, stirring and dispersing, adding EDC thereto, using argon as reaction protection gas, controlling the temperature to 100-110° C., reacting for 8-12 hours, and after the reaction is completed, centrifuging, washing with deionized water, and drying to obtain modified graphene; S3, adding ABS resin to butyl acetate, stirring and dissolving at 80°C, adding diisopropylbenzene peroxide, maleic anhydride and hexenyl borate thereto, reacting for 8-12 hours under nitrogen protection, cooling to room temperature after the reaction, adding ethanol thereto, filtering, washing with ethanol, extracting, and drying to obtain modified ABS; S4, adding the dried PC resin, ABS resin, modified ABS, modified graphene, and antioxidant into a twin-screw extruder for melt extrusion, cooling and granulating, and then placing in an injection molding machine for injection molding to obtain a high-strength flame-retardant PC / ABS alloy.

2. The high-strength flame-retardant PC / ABS alloy according to claim 1, characterized in that: In the S1, the mass ratio of the intermediate product A, the intermediate product C and triethylamine is 2.2-2.5:1:0.8-1.

3. The high-strength flame-retardant PC / ABS alloy according to claim 1, characterized in that: In the S2, the mass ratio of graphene oxide to the intermediate product C is 1:3-5.

4. The high-strength flame-retardant PC / ABS alloy according to claim 1, characterized in that: In S3, the mass ratio of ABS resin, dicumyl peroxide, maleic anhydride and hexenyl borate is 100:2-4:10-15:5-10.

5. The high-strength flame-retardant PC / ABS alloy according to claim 1, characterized in that: In S1, the preparation method of the intermediate product A comprises the following steps: Phosphorus oxychloride was added to 1,2-dichloroethane, nitrogen was introduced, magnetic stirring was performed, and then p-hydroxystyrene and triethylamine were added thereto. The reaction was stirred for 1-2 hours at room temperature, and the temperature was raised to 55-65°C and the reaction was performed for 10-14 hours. After the reaction was completed, the reaction was filtered and distilled under reduced pressure to obtain intermediate product A.

6. The high-strength flame-retardant PC / ABS alloy according to claim 5, characterized in that: The mass ratio of the phosphorus oxychloride, p-hydroxystyrene and triethylamine is 1:1.5-1.6:1.8-2.

2.

7. The high-strength flame-retardant PC / ABS alloy according to claim 1, characterized in that: In S1, the preparation method of the intermediate product C comprises the following steps: SS1. Add p-hydroxybenzaldehyde and boric acid to toluene, first heat to 100°C, react for 1-2h, then heat to 120-130°C, react for 3-4h, continue to heat to 150-160°C, react for 4-6h, after the reaction, distill under reduced pressure, dry to obtain intermediate product B; SS2. Add p-aminophenol to ethanol, stir and disperse, then add intermediate product B, control the temperature to 30-40°C, add formic acid, react for 4-6 hours, after the reaction is completed, wash with ether, filter, and dry to obtain intermediate product C.

8. The high-strength flame-retardant PC / ABS alloy according to claim 7, characterized in that: In the SS1, the mass ratio of p-hydroxybenzaldehyde to boric acid is 10-14:

1.

9. The high-strength flame-retardant PC / ABS alloy according to claim 7, characterized in that: In the SS2, the mass ratio of p-aminophenol to the intermediate product B is 1.8-2:1.

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