A high-strength flame-retardant PC / ABS alloy and its preparation method

Abstract

The present 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 composed of the following components 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. By preparing modified ABS and modified graphene and introducing them into the alloy, the present invention improves the flame-retardant performance, mechanical properties, and thermal stability of the PC / ABS alloy, and increases the application range of the PC / ABS alloy.

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

[0006] 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.

[0007] (II) Technical solution

[0008] 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;

[0009] The preparation method of the high-strength flame-retardant PC / ABS alloy comprises the following steps:

[0010] S1. Add the intermediate A into 1,2-dichloroethane, stir evenly, add the intermediate C and triethylamine thereto, control the temperature at 60 - 70 °C, react for 8 - 12 h. After the reaction is completed, perform suction filtration and vacuum distillation to obtain the hexaenyl borate. Among them, the mass ratio of the intermediate A, the intermediate C, and triethylamine is 2.2 - 2.5:1:0.8 - 1. In this reaction, the chlorine atom contained in the intermediate A is used to carry out a substitution reaction with the phenolic hydroxyl group in the intermediate C to obtain the hexaenyl borate. In the intermediate C, not only the synergistic flame-retardant element phosphorus element is introduced, but also the hexaenyl structure is introduced. The reaction route is as follows:

[0011] , where R is ;

[0012] S2. Add graphene oxide and the intermediate C into the N,N-dimethylformamide solvent, stir and disperse, then add 1-ethyl(-3-dimethylaminopropyl)carbodiimide (EDC) thereto. Use argon as the reaction protective gas, control the temperature at 100 - 110 °C, react for 8 - 12 h. After the reaction is completed, perform centrifugation, wash with deionized water, and dry to obtain the modified graphene. Among them, the mass ratio of graphene oxide and the intermediate C is 1:3 - 5. In this reaction, the hydroxyl group contained in the intermediate C is used to react with the carboxyl group on the surface of graphene oxide to form a chemical bond, which can disperse graphene oxide, reduce the aggregation degree of graphene oxide, and enhance its dispersibility in the material. The reaction route is as follows:

[0013] ;

[0014] S3. Add ABS resin into butyl acetate, stir and dissolve at 80 °C. Add diisopropylbenzene peroxide, maleic anhydride, and hexenyl borate ester into it. Under nitrogen protection, react for 8 - 12 h. After the reaction is completed, cool to room temperature, add ethanol, filter by suction, wash with ethanol, extract, and dry to obtain modified ABS. Among them, the mass ratio of ABS resin, diisopropylbenzene peroxide, maleic anhydride, and hexenyl borate ester is 100:2 - 4:10 - 15:5 - 10. Using diisopropylbenzene peroxide as the initiator and maleic anhydride and hexenyl borate ester as graft monomers, graft the two onto ABS to obtain modified ABS. In this reaction, the alkenyl structures contained in maleic anhydride and hexenyl borate ester are polymerized with the alkenyl structures contained in ABS. On the one hand, because the hexenyl borate ester contains a hexenyl structure, therefore, the prepared modified ABS contains more chemical crosslinking sites. Introducing it into the material can increase the mechanical properties of the material. On the other hand, the ABS in the modified ABS graft can intersect with the ABS in the alloy and can achieve complete compatibility. And the MAH monomer contained in the modified ABS can perform transesterification with the terminal phenolic hydroxyl group in PC to generate chemical linkages, increasing the compatibility between ABS and PC;

[0015] S4. Add dry PC resin, ABS resin, modified ABS, modified graphene, and antioxidant into a twin-screw extruder for melt extrusion, cool and pelletize, and then place it in an injection molding machine for injection molding to obtain a high-strength flame-retardant PC / ABS alloy. Among them, 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.

[0016] Preferably, in the said S1, the preparation method of intermediate A includes the following steps:

[0017] Add phosphorus oxychloride into 1,2-dichloroethane, introduce nitrogen, stir magnetically, and then add p-hydroxystyrene and triethylamine into it. Stir and react at room temperature for 1 - 2 h, then raise the temperature to 55 - 65 °C and react for 10 - 14 h. After the reaction is completed, filter by suction and distill under reduced pressure to obtain intermediate A. Among them, 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:

[0018] ;

[0019] Preferably, in the said S1, the preparation method of intermediate C includes the following steps

[0020] SS1. Add p-hydroxybenzaldehyde and boric acid to toluene. First, heat the mixture to 100 °C and react for 1 - 2 h. Then, heat it to 120 - 130 °C and react for 3 - 4 h. Continue to heat it to 150 - 160 °C and react for 4 - 6 h. After the reaction is completed, perform vacuum distillation and drying to obtain intermediate product B. Among them, the mass ratio of p-hydroxybenzaldehyde to boric acid is 10 - 14:1. In this reaction, intermediate product B is obtained by dehydration of the phenolic hydroxyl group in p-hydroxybenzaldehyde and boric acid. Organic borate esters are prone to hydrolysis. In the present invention, a benzene ring structure is introduced around boric acid. The benzene ring can provide steric hindrance, shield boron atoms, prevent water molecules from approaching, improve stability, and reduce the hydrolysis effect. The reaction route is as follows:

[0021] ;

[0022] SS2. Add p-aminophenol to ethanol, stir and disperse it. Then add intermediate product B to it, control the temperature at 30 - 40 °C, add formic acid to it, and react for 4 - 6 h. After the reaction is completed, wash it with ether, filter, and dry to obtain intermediate product C. Among them, the mass ratio of p-aminophenol to intermediate product B is 1.8 - 2:1. In this reaction, a Schiff base condensation reaction is carried out between the amino group in p-aminophenol and the aldehyde group in intermediate product B to obtain intermediate product C. A heat-resistant Schiff base structure is introduced into intermediate product C. When heated, the Schiff base structure can generate 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 as follows:

[0023] 。

[0024] (III) Beneficial technical effects

[0025] Graphene used in the present invention is prone to agglomeration itself. It is modified so that the material forms chemical bonds with graphene, solving the problem that graphene is difficult to disperse evenly in the material. It 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 an inorganic nanoparticle, it can synergistically improve the heat resistance of the material with the heat-resistant Schiff base structure and the rigid benzene ring structure; on the other hand, inorganic graphene oxide, due to its unique two-dimensional layered structure, can improve the dense and continuous carbon layer during the degradation process, thereby preventing heat transfer and delaying degradation, forming an inorganic flame retardant system.

[0026] The alloy prepared by the present invention contains organic phosphorus element, organic nitrogen element and organic boron element. Organic phosphorus will first decompose by heat to generate polyphosphoric acid, which promotes the rapid dehydration and carbonization of the substrate and plays a flame retardant role in the condensed phase; organic nitrogen thermally decomposes endothermically to generate non-combustible gases such as NH3 and N2, diluting the oxygen concentration and playing a flame retardant role in the gas phase. At the same time, when the gas escapes, it can act on the carbon layer generated by organic phosphorus and increase its area, exerting the synergistic effect of the condensed phase and the gas phase; organic boron generates boric acid during the combustion process, and when it cracks, it forms a glassy melt-like substance covering the surface of the material, forming a glassy protective layer, which not only reduces the further oxidation of the carbon layer, but also prevents the escape of volatile combustibles, and plays a flame retardant role in both the gas phase and the condensed phase at the same time. The three elements of nitrogen, phosphorus and boron form an organic flame retardant system. It forms an organic-inorganic synergistic flame retardant system with the inorganic flame retardant system to jointly improve the flame retardant performance of the alloy. In addition, the alloy material prepared by the present invention contains more branched chain structures, which can entangle with each other to generate physical crosslinking sites. When subjected to external stress, the stress can be dispersed to other molecular chains through the crosslinking sites, and then cooperate with graphene to improve the mechanical properties of the material. Detailed implementation mode

[0027] Preparation method of graphene oxide: Add 46 mL of concentrated sulfuric acid, 1 g of sodium nitrate, and 2 g of graphite into a beaker, control the temperature at 10 °C, add 6 g of potassium permanganate thereto and react for 1 h, raise the temperature to 35 °C, react for 2 h, add 96 mL of deionized water thereto, raise the temperature to 95 °C, react for 30 min, then add hydrogen peroxide with a mass fraction of 30% until the solution turns bright yellow, filter, wash with deionized water until neutral, centrifuge, and dry to obtain graphene oxide. Example 1

[0028] (1) Add 1 g of phosphorus oxychloride to 1,2-dichloroethane, introduce nitrogen, stir magnetically, then add 1.5 g of p-hydroxystyrene and 1.8 g of triethylamine thereto, 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 by suction and distill under reduced pressure to obtain intermediate product A.

[0029] (2) Add 10 g of p-hydroxybenzaldehyde and 1 g of boric acid to toluene, first raise the temperature to 100 °C and react for 2 h, then raise the temperature to 130 °C and react for 3 h, continue to raise the temperature to 160 °C and react for 4 h. After the reaction is completed, distill under reduced pressure and dry to obtain intermediate product B.

[0030] (3) Add 20 g of p-aminophenol to ethanol, stir and disperse it, then add 10 g of intermediate product B thereto, control the temperature at 30 °C, add 12 mL of formic acid thereto, and react for 6 h. After the reaction is completed, wash with ether, filter, and dry to obtain intermediate product C.

[0031] (4) Add 2.2 g of intermediate A to 1,2-dichloroethane, stir evenly, add 1 g of intermediate C and 1 g of triethylamine thereto, control the temperature at 65 °C, react for 12 h, after the reaction is completed, carry out suction filtration and vacuum distillation to obtain hexaenyl borate.

[0032] (5) Add 10 g of graphene oxide and 50 g of intermediate C to N,N-dimethylformamide solvent, stir and disperse, then add 10 mL of EDC thereto, use argon as the reaction protective gas, control the temperature at 110 °C, react for 8 h, after the reaction is completed, carry out centrifugation, wash with deionized water, and dry to obtain modified graphene.

[0033] (6) Add 20 g of ABS resin to butyl acetate, dissolve it by stirring at 80 °C, add 0.4 g of diisopropylbenzene peroxide, 3 g of maleic anhydride, and 1 g of hexaenyl borate thereto, under nitrogen protection, react for 10 h, after the reaction is completed, cool to room temperature, add ethanol thereto, carry out suction filtration, wash with ethanol, extract, and dry to obtain modified ABS.

[0034] (7) Add 70 g of dry PC resin, 30 g of ABS resin, 10 g of modified ABS, 5 g of modified graphene, and 0.1 g 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, 245 °C, the head temperature is 250 °C, and the screw speed is 100 r / min. Cool and pelletize, then place it in an injection molding machine for injection molding. The injection molding temperatures of the injection molding machine are 180 °C, 245 °C, 250 °C, 255 °C, and the injection pressure is 55 MPa to obtain a high-strength flame-retardant PC / ABS alloy. Example Two

[0035] (1) Add 1 g of phosphorus oxychloride to 1,2-dichloroethane, introduce nitrogen, stir magnetically, then add 1.6 g of p-hydroxystyrene and 2.2 g of triethylamine thereto, stir and react at room temperature for 1 h, raise the temperature to 65 °C, react for 10 h, after the reaction is completed, carry out suction filtration and vacuum distillation to obtain intermediate A.

[0036] (2) Add 14 g of p-hydroxybenzaldehyde and 1 g of boric acid to toluene, first raise the temperature to 100 °C, react for 1 h, then raise the temperature to 120 °C, react for 4 h, continue to raise the temperature to 155 °C, react for 5 h, after the reaction is completed, carry out vacuum distillation and drying to obtain intermediate B.

[0037] (3) Add 19 g of p-aminophenol to ethanol, stir and disperse, then add 10 g of intermediate B thereto, control the temperature at 40 °C, add 12 mL of formic acid thereto, react for 4 h, after the reaction is completed, wash with ether, filter, and dry to obtain intermediate C.

[0038] (4) Add 2.5 g of intermediate A to 1,2-dichloroethane, stir evenly, add 1 g of intermediate C and 0.8 g of triethylamine thereto, control the temperature at 60 °C, react for 10 h, after the reaction is completed, perform suction filtration and vacuum distillation to obtain hexaenyl borate.

[0039] (5) Add 10 g of graphene oxide and 30 g of intermediate C to N,N-dimethylformamide solvent, stir and disperse, then add 10 mL of EDC thereto, use argon as the reaction protective gas, control the temperature at 105 °C, react for 12 h, after the reaction is completed, centrifuge, wash with deionized water, and dry to obtain modified graphene.

[0040] (6) Add 20 g of ABS resin to butyl acetate, dissolve it by stirring at 80 °C, add 0.5 g of diisopropylbenzene peroxide, 3 g of maleic anhydride, and 1 g of hexaenyl borate thereto, react for 12 h under nitrogen protection, after the reaction is completed, cool to room temperature, add ethanol thereto, perform suction filtration, wash with ethanol, extract, and dry to obtain modified ABS.

[0041] (7) Add 70 g of dry PC resin, 30 g of ABS resin, 15 g of modified ABS, 8 g of modified graphene, and 0.3 g 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, 245 °C, the head temperature is 250 °C, and the screw speed is 100 r / min. Cool and pelletize, then place it in an injection molding machine for injection molding. The injection molding temperatures of the injection molding machine are 180 °C, 245 °C, 250 °C, 255 °C, and the injection pressure is 55 MPa to obtain a high-strength flame-retardant PC / ABS alloy. Example 3

[0042] (1) Add 1 g of phosphorus oxychloride to 1,2-dichloroethane, introduce nitrogen, stir magnetically, then add 1.6 g of p-hydroxystyrene and 2 g of triethylamine thereto, stir and react at room temperature for 2 h, raise the temperature to 55 °C, and react for 14 h. After the reaction is completed, perform suction filtration and vacuum distillation to obtain intermediate A.

[0043] (2) Add 13 g of p-hydroxybenzaldehyde and 1 g of boric acid to toluene, first raise the temperature to 100 °C and react for 1 h, then raise the temperature to 125 °C and react for 3 h, continue to raise the temperature to 150 °C and react for 6 h. After the reaction is completed, perform vacuum distillation and drying to obtain intermediate B.

[0044] (3) Add 18 g of 4-aminophenol to ethanol, stir to disperse, then add 10 g of intermediate B thereto, control the temperature at 35 °C, add 12 mL of formic acid thereto, react for 6 h, after the reaction is completed, wash with ether, filter, and dry to obtain intermediate C.

[0045] (4) Add 2.4 g of intermediate A to 1,2-dichloroethane, stir evenly, add 1 g of intermediate C and 0.9 g of triethylamine thereto, control the temperature at 70 °C, react for 8 h, after the reaction is completed, carry out suction filtration and vacuum distillation to obtain hexaenyl borate.

[0046] (5) Add 10 g of graphene oxide and 40 g of intermediate C to N,N-dimethylformamide solvent, stir to disperse, then add 10 mL of EDC thereto, use argon as the reaction protective gas, control the temperature at 100 °C, react for 10 h, after the reaction is completed, centrifuge, wash with deionized water, and dry to obtain modified graphene.

[0047] (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 hexaenyl borate thereto, under nitrogen protection, react for 8 h, after the reaction is completed, cool to room temperature, add ethanol thereto, carry out suction filtration, wash with ethanol, extract, and dry to obtain modified ABS.

[0048] (7) Add 70 g of dry PC resin, 30 g of ABS resin, 20 g of modified ABS, 10 g of modified graphene, and 0.4 g 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 100 r / min. Cool and pelletize, then place it 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 pressure is 55 MPa to obtain a high-strength flame-retardant PC / ABS alloy.

[0049] Comparative Example 1

[0050] The difference between this comparative example and Example 1 is that: modified ABS is not contained in step (7).

[0051] Comparative Example 2

[0052] The difference between this comparative example and Example 1 is that: modified graphene is not contained in step (7).

[0053] Use an oxygen index instrument to test the oxygen index of the material.

[0054] Use a horizontal and vertical burning test chamber to test the vertical burning grade of the material.

[0055] Table 1:

[0056]

[0057] As can be seen from the above table, the alloy material prepared by the present invention has good flame retardant properties.

[0058] The tensile properties of the material were tested using a universal material testing machine, and the tensile rate was 50 mm / min.

[0059] The notched impact strength of the material was tested using a pendulum impact tester.

[0060] Table 2:

[0061]

[0062] As can be seen from the table, the material prepared by the present invention has good mechanical properties.

[0063] With reference to the ISO75-1-2013 standard, the heat distortion temperature was tested and measured under the conditions of a load of 1.80 MPa and a heating rate of 120 °C / h.

[0064] Table 3:

[0065]

[0066] The higher the heat distortion temperature, the higher the thermal stability. As can be seen from the table, the material prepared by the present invention has high 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 part 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 thereto, control the temperature at 60 - 70 °C, react for 8 - 12 h, after the reaction ends, carry out suction filtration and vacuum distillation to obtain hexaenyl borate; S2. Add graphene oxide and intermediate product C to N,N-dimethylformamide solvent, stir and disperse, then add EDC thereto, use argon as the reaction protective gas, control the temperature at 100 - 110 °C, react for 8 - 12 h, after the reaction ends, carry out centrifugation, wash with deionized water, and dry to obtain modified graphene; S3. Add ABS resin to butyl acetate, dissolve it by stirring at 80 °C, add diisopropylbenzene peroxide, maleic anhydride, and hexaenyl borate thereto, react for 8 - 12 h under nitrogen protection, after the reaction ends, cool to room temperature, add ethanol thereto, carry out suction filtration, wash with ethanol, extract, and dry to obtain modified ABS; S4. Add the dried PC resin, ABS resin, modified ABS, modified graphene, and antioxidant to a twin-screw extruder for melt extrusion, cool and pelletize, then place it in an injection molding machine for injection molding to obtain the high-strength flame-retardant PC / ABS alloy; The preparation method of the intermediate product A comprises the following steps: Add phosphorus oxychloride to 1,2-dichloroethane, introduce nitrogen, stir magnetically, then add p-hydroxystyrene and triethylamine thereto, where the mass ratio of phosphorus oxychloride, p-hydroxystyrene, and triethylamine is 1:1.5 - 1.6:1.8 - 2.2, stir and react at room temperature for 1 - 2 h, raise the temperature to 55 - 65 °C, react for 10 - 14 h, after the reaction ends, carry out suction filtration and vacuum distillation to obtain intermediate product A; The preparation method of the intermediate product C comprises the following steps: SS1. Add p-hydroxybenzaldehyde and boric acid to toluene, where the mass ratio of p-hydroxybenzaldehyde and boric acid is 10 - 14:1, first raise the temperature to 100 °C, react for 1 - 2 h, then raise the temperature to 120 - 130 °C, react for 3 - 4 h, continue to raise the temperature to 150 - 160 °C, react for 4 - 6 h, after the reaction ends, carry out vacuum distillation and dry to obtain intermediate product B; SS2. Add p-aminophenol to ethanol, stir and disperse, then add intermediate product B thereto, control the temperature at 30 - 40 °C, where the mass ratio of p-aminophenol and intermediate product B is 1.8 - 2:1, add formic acid thereto, react for 4 - 6 h, after the reaction ends, wash with ether, filter, and dry to obtain intermediate product C.

2. The high-strength flame-retardant PC / ABS alloy according to claim 1, wherein In the step S1, the mass ratio of intermediate product A, 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, wherein In the step S2, the mass ratio of graphene oxide and intermediate product C is 1:3 - 5.

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

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