Flame-retardant modified PC-ABS plastic and preparation method thereof

Abstract

The application relates to the technical field of plastics, and discloses a flame-retardant modified PC-ABS plastic and a preparation method thereof. The flame-retardant modified PC-ABS plastic comprises PC resin, ABS resin, a mercapto flame retardant, an initiator and an antioxidant in a mass ratio of (65-85):(15-35):(5-12):(0.15-0.4):(0.1-0.2). The mercapto flame retardant contains DOPO and a triazine ring structure, can play a role in condensed phase flame retardation and gas phase flame retardation, reduces the limiting oxygen index, and improves the flame-retardant performance. The mercapto flame retardant containing a large number of ester groups forms sulfur free radicals under the action of dicumyl peroxide, and the sulfur free radicals have an addition crosslinking reaction with alkenyl groups of ABS, so that the PC-ABS plastic has better interfacial compatibility between ABS and PC polycarbonate, and the mechanical properties of the PC-ABS plastic are improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of plastics, in particular to a flame-retardant modified PC-ABS plastic and a preparation method thereof. BACKGROUND

[0002] Polycarbonate (PC) has certain flame retardance, high transparency and good mechanical strength, and can be used as an engineering plastic in the fields of electronic appliances, automobile industry, building materials and the like. Acrylonitrile-butadiene-styrene (ABS) copolymer has good elasticity and toughness, low cost and excellent temperature resistance, and when combined with polycarbonate, the plastic alloy has the advantages of PC and ABS, better performance and wider application. However, the flame retardance of PC / ASB plastic is poor, which limits the practical application thereof in fireproof fields and the like.

[0003] Generally, the flame retardance of plastic can be improved by adding a flame retardant, and the preparation method of the nitrogen-phosphorus type flame retardant is various, the char-forming capacity is strong, and the flame retardance is excellent, so the flame retardant has important application in high molecular materials such as plastic and fiber. However, if the common flame retardant has poor compatibility with PC and ABS, the mechanical properties of the plastic will be affected. The application aims to improve the flame retardance of PC-ABS plastic by using a flame retardant and keeping excellent mechanical strength. SUMMARY

[0004] The application solves the problems of poor flame retardance of PC-ABS plastic and reduction of mechanical properties of plastic caused by adding a flame retardant.

[0005] The technical scheme of the application is as follows: a flame-retardant modified PC-ABS plastic and a preparation method thereof, the PC-ABS plastic comprises PC resin, ABS resin, mercapto flame retardant, initiator and antioxidant, and the mass ratio of the PC resin, ABS resin, mercapto flame retardant, initiator and antioxidant is (65-85):(15-35):(5-12):(0.15-0.4):(0.1-0.2).

[0006] The preparation method of the PC-ABS plastic is as follows:

[0007] (1) adding cysteine-based DOPO-HQ and 2,4,6-tris(4-formylphenyl)-1,3,5-triazine (CAS registration number 443922-06-3) into dimethyl sulfoxide, stirring and reacting, cooling, filtering, washing with ethanol and dichloromethane in sequence, and drying to obtain the mercapto flame retardant. The preparation reaction formula is as follows:

[0008] .

[0009] (2) mixing the PC resin, ABS resin, mercapto flame retardant, initiator and antioxidant, extruding in a double-screw extruder, cutting into particles, and then injection molding in an injection molding machine to obtain the flame-retardant modified PC-ABS plastic.

[0010] Further, the molar ratio of cysteine-based DOPO-HQ and 2,4,6-tris(4-formylphenyl)-1,3,5-triazine in (1) is (1.4-1.6):1.

[0011] Further, the reaction in (1) is carried out in a nitrogen atmosphere, the reaction temperature is 140-160℃, and the reaction time is 24-36h.

[0012] Further, the initiator in (2) is a peroxide, including dicumyl peroxide.

[0013] Further, the antioxidant in (2) is a hindered phenolic antioxidant, including antioxidant 1010.

[0014] Further, the temperature of each section of the twin-screw extruder in (2) is 170-260℃, and the screw rotation speed is 150-250r / min.

[0015] Further, the temperature of each section of the injection molding machine in (2) is 180-265℃, and the pressure is 50-60MPa.

[0016] Further, the preparation method of cysteine-based DOPO-HQ includes: adding 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide (CAS registration number 99208-50-1), cysteine (CAS registration number 3374-22-9), and p-toluenesulfonic acid in toluene in a molar ratio of 1:(2.4-3.2):(0.3-0.4), heating to 90-100℃, condensing refluxing for 12-18h, removing toluene by rotary evaporation, and separating the product by column chromatography, eluting with a solution of ethyl acetate and petroleum ether to obtain cysteine-based DOPO-HQ. The preparation reaction formula is:

[0017] .

[0018] The application has the beneficial technical effects that: the cysteine-based DOPO-HQ and 2,4,6-tris(4-formylphenyl)-1,3,5-triazine are subjected to a polymerization reaction to obtain a mercapto flame retardant, which is then blended and granulated with PC polycarbonate, ABS resin, dicumyl peroxide, etc., and injection molded to obtain a flame-retardant modified PC-ABS plastic. The mercapto flame retardant contains DOPO and triazine ring structures, forms a nitrogen-phosphorus flame retardant, can play a condensed phase flame retardant and gas phase flame retardant role, forms an expanded carbon layer on the surface of the plastic, can isolate oxygen and prevent heat transfer, reduces the limiting oxygen index, and improves the flame retardant performance.

[0019] The thiol flame retardant of the present application is an over-branched macromolecular polymer, containing a large number of thiol groups in the molecular chain, under the action of dicumyl peroxide, the thiol groups form sulfur radicals, and addition cross-linking reaction occurs with the alkenyl groups of ABS, so that the flame retardant and ABS are chemically bonded, and the cross-linking degree between ABS molecular chains is improved, which is beneficial to improve the mechanical properties of ABS and its plastics.

[0020] The thiol flame retardant of the present application contains a large number of ester groups in the molecular main chain, which has good compatibility with PC polycarbonate, so that the ABS bonded with the flame retardant has better interfacial compatibility with PC polycarbonate, further improving the mechanical properties of PC-ABS plastics, and having higher tensile strength and bending strength. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be described below clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0022] The polycarbonate resin K-1300Y described below is from Dongguan Heshengyuan New Material Technology Co., Ltd. The ABS resin is Sony CF25L from Dongguan Kaisheng Plastic Raw Material Co., Ltd.

[0023] Example 1

[0024] (1) 50 mmol 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, 160 mmol cysteine, 15 mmol p-toluenesulfonic acid were added to 200 mL of toluene, heated to 90℃, and condensed to reflux for 18 h. The toluene was removed by rotary evaporation, and the product was separated by column chromatography, eluted with a solution of ethyl acetate and petroleum ether, to obtain cysteine-based DOPO-HQ.

[0025] (2) 75 mmol of cysteine-based DOPO-HQ, 50 mmol of 2,4,6-tris(4-formylphenyl)-1,3,5-triazine were added to 600 mL of dimethyl sulfoxide, heated to 140℃ under nitrogen atmosphere, and stirred for 36 h. After cooling, the filter cake was washed with ethanol and dichloromethane in sequence, and dried to obtain the thiol flame retardant.

[0026] (3) 850 g PC resin, 150 g ABS resin, 50 g mercapto flame retardant, 1.5 g dicumyl peroxide, 1.4 g antioxidant 1010 were mixed, extruded in a twin-screw extruder, the temperature of each section was 170°C, 215°C, 230°C, 250°C, 260°C, 260°C, the screw speed was 250 r / min, and then pelletized, and then injection molded in an injection molding machine, the temperature of each section was 180°C, 240°C, 260°C, 265°C, and the pressure was 60 MPa, to obtain a flame-retardant modified PC-ABS plastic.

[0027] Example 2

[0028] (1) 50 mmol 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, 120 mmol cysteine, 20 mmol p-toluenesulfonic acid were added to 150 mL of toluene, heated to 100°C, and refluxed for 12 h, and then toluene was removed by rotary evaporation, and the product was separated by column chromatography and eluted with an ethyl acetate and petroleum ether solution to obtain a cysteine-based DOPO-HQ.

[0029] (2) 70 mmol of the cysteine-based DOPO-HQ prepared in (1) and 50 mmol of 2,4,6-tris(4-formylphenyl)-1,3,5-triazine were added to 600 mL of dimethyl sulfoxide, heated to 160°C under a nitrogen atmosphere, and stirred for 24 h, and then cooled, filtered, and washed with ethanol and dichloromethane in sequence, and dried to obtain a mercapto flame retardant.

[0030] (3) 800 g PC resin, 200 g ABS resin, 70 g mercapto flame retardant, 2.2 g dicumyl peroxide, and 1 g antioxidant 1010 were mixed, extruded in a twin-screw extruder, the temperature of each section was 170°C, 215°C, 230°C, 250°C, 260°C, 260°C, the screw speed was 250 r / min, and then pelletized, and then injection molded in an injection molding machine, the temperature of each section was 180°C, 240°C, 260°C, 265°C, and the pressure was 60 MPa, to obtain a flame-retardant modified PC-ABS plastic.

[0031] Example 3

[0032] (1) 80 mmol of the cysteine-based DOPO-HQ prepared in Example 1 and 50 mmol of 2,4,6-tris(4-formylphenyl)-1,3,5-triazine were added to 800 mL of dimethyl sulfoxide, heated to 150°C under a nitrogen atmosphere, and stirred for 24 h, and then cooled, filtered, and washed with ethanol and dichloromethane in sequence, and dried to obtain a mercapto flame retardant.

[0033] (2) 700 g PC resin, 300 g ABS resin, 100 g mercapto flame retardant, 3.2 g dicumyl peroxide, 2 g antioxidant 1010 were mixed and extruded in a twin-screw extruder, the temperature of each section was 170°C, 215°C, 230°C, 250°C, 260°C, 260°C, the screw rotation speed was 150 r / min, and the granulation was then performed, and then injection molding was performed in an injection molding machine, the temperature of each section was 180°C, 240°C, 260°C, 265°C, and the pressure was 50 MPa, to obtain a flame-retardant modified PC-ABS plastic.

[0034] Example 4

[0035] (1) 650 g PC resin, 350 g ABS resin, 120 g mercapto flame retardant (prepared in Example 1), 4 g dicumyl peroxide, and 2 g antioxidant 1010 were mixed and extruded in a twin-screw extruder, the temperature of each section was 170°C, 215°C, 230°C, 250°C, 260°C, 260°C, the screw rotation speed was 250 r / min, and the granulation was then performed, and then injection molding was performed in an injection molding machine, the temperature of each section was 180°C, 240°C, 260°C, 265°C, and the pressure was 50 MPa, to obtain a flame-retardant modified PC-ABS plastic.

[0036] Comparative Example 1

[0037] (1) 850 g PC resin, 150 g ABS resin, 1.5 g dicumyl peroxide, and 1.4 g antioxidant 1010 were mixed and extruded in a twin-screw extruder, the temperature of each section was 170°C, 215°C, 230°C, 250°C, 260°C, 260°C, the screw rotation speed was 250 r / min, and the granulation was then performed, and then injection molding was performed in an injection molding machine, the temperature of each section was 180°C, 240°C, 260°C, 265°C, and the pressure was 60 MPa, to obtain a PC-ABS plastic.

[0038] Comparative Example 2

[0039] (1) 850 g PC resin, 150 g ABS resin, 50 g cysteine-based DOPO-HQ (prepared in Example 1), 1.5 g dicumyl peroxide, and 1.4 g antioxidant 1010 were mixed and extruded in a twin-screw extruder, the temperature of each section was 170°C, 215°C, 230°C, 250°C, 260°C, 260°C, the screw rotation speed was 250 r / min, and the granulation was then performed, and then injection molding was performed in an injection molding machine, the temperature of each section was 180°C, 240°C, 260°C, 265°C, and the pressure was 60 MPa, to obtain a flame-retardant modified PC-ABS plastic.

[0040] Comparative Example 3

[0041] (1) The intermediate product C1 was prepared according to the method of Tianjin University of Technology and Education postgraduate thesis “Preparation of DOPO derivatives flame retardant and study on flame retardant properties of polylactic acid composite”. 32 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and 5.35 g of 4,4'-diaminobenzophenone were mixed, heated to 190°C, stirred for 3 h, cooled to 100°C, 150 mL of toluene was added, the precipitate was washed with toluene after filtration, then recrystallized in tetrahydrofuran to obtain the intermediate product C1, and the structural formula is .

[0042] (2) 75 mmol of intermediate product C1 and 50 mmol of 2,4,6-tris(4-formylphenyl)-1,3,5-triazine were added to 600 mL of dimethyl sulfoxide, heated to 140°C under nitrogen atmosphere, stirred for 36 h, cooled, filtered, and the filter cake was washed with ethanol and dichloromethane in sequence, and dried to obtain the flame retardant.

[0043] (3) 850 g of PC resin, 150 g of ABS resin, 50 g of flame retardant, 1.5 g of dicumyl peroxide, and 1.4 g of antioxidant 1010 were mixed, extruded in a twin-screw extruder, the temperature of each section was 170°C, 215°C, 230°C, 250°C, 260°C, and 260°C, the screw rotation speed was 250 r / min, and the granulation was then performed in an injection molding machine, the temperature of each section was 180°C, 240°C, 260°C, and 265°C, and the pressure was 60 MPa, to obtain the flame-retardant modified PC-ABS plastic.

[0044] The flame retardant properties of the PC-ABS plastic were tested according to the method specified in GB / T 2406.1-2008 standard.

[0045] The tensile strength was tested according to the method specified in GB / T 1040.1-2018 standard, and the bending strength was tested according to the method specified in GB / T 9341-2008 standard.

[0046] Table 1: Performance test of PC-ABS plastic

[0047]

[0048] The PC-ABS plastic of the comparative example 1 does not add the flame retardant, the limiting oxygen index is low, and the flame retardancy is poor. The PC-ABS plastic of the examples 1-4 adds the mercapto flame retardant, which contains DOPO and triazine ring structure, forms a nitrogen-phosphorus flame retardant, can play a condensed phase flame retardant and gas phase flame retardant effect, forms an expanded carbon layer on the surface of the plastic, can isolate oxygen and prevent heat transfer, has a good flame retardant effect, reduces the limiting oxygen index, and the mercapto flame retardant is an ultrabranched macromolecular polymer, contains a large number of mercapto groups in the molecular chain, forms sulfur radicals under the action of dicumyl peroxide, and has an addition crosslinking reaction with the alkenyl group of ABS, so that the flame retardant and ABS have a chemical bonding effect, improves the crosslinking degree between ABS molecular chains, is beneficial to improving the mechanical properties of ABS and its plastic, and the flame retardant contains a large number of ester groups in the molecular main chain, has good compatibility with PC polycarbonate, so that the ABS bonded with the branched flame retardant and the PC polycarbonate have better interface compatibility, further improve the mechanical properties of the PC-ABS plastic, and have higher tensile strength and bending strength.

[0049] The cysteine-based DOPO-HQ of the comparative example 2 does not contain a triazine ring structure, does not form a nitrogen-phosphorus flame retardant system, and has low limiting oxygen index and poor flame retardancy. And the cysteine-based DOPO-HQ contains mercapto groups, which can react with the alkenyl group of ABS, but it is a small molecule compound, contains only two mercapto groups, and has large steric hindrance, forms a crosslinking effect with ABS, and is not conducive to improving the mechanical strength of ABS and its plastic. And the cysteine-based DOPO-HQ is a small molecule compound, has a small amount of ester groups, and is difficult to effectively improve the compatibility between ABS and PC polycarbonate after chemical bonding, resulting in low tensile strength and bending strength.

[0050] The intermediate product C1 without mercapto and ester groups in the comparative example 3 is subjected to a Schiff base polymerization reaction with 2,4,6-tris(4-formylphenyl)-1,3,5-triazine, the obtained flame retardant does not contain a large amount of mercapto and ester groups, cannot react with ABS, and does not improve the compatibility between ABS and PC polycarbonate, resulting in low tensile strength and bending strength of the plastic.

[0051] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can make equivalent replacement or change according to the technical scheme and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A flame-retardant modified PC-ABS plastic, characterized in that, The fire-retardant modified PC-ABS plastic comprises PC resin, ABS resin, mercapto flame retardant, initiator and antioxidant in a mass ratio of (65-85):(15-35):(5-12):(0.15-0.4):(0.1-0.2). The preparation method of the mercapto flame retardant comprises: adding cysteine-based DOPO-HQ and 2,4,6-tris(4-aldehyde phenyl)-1,3,5-triazine into dimethyl sulfoxide, stirring and reacting, cooling, filtering, washing the product, drying, and obtaining the mercapto flame retardant. The structural formula of the cysteine-based DOPO-HQ is ; The molar ratio of the cysteine-based DOPO-HQ and 2,4,6-tris(4-aldehyde phenyl)-1,3,5-triazine is (1.4-1.6):

1. The initiator is a peroxide, comprising dicumyl peroxide.

2. The flame-retardant modified PC-ABS plastic according to claim 1, characterized in that, The reaction is carried out in a nitrogen atmosphere, the reaction temperature is 140-160℃, and the reaction time is 24-36h.

3. The flame-retardant modified PC-ABS plastic according to claim 1, characterized in that, The antioxidant is a hindered phenolic antioxidant, comprising antioxidant 1010.

4. The flame-retardant modified PC-ABS plastic according to claim 1, characterized in that, The preparation method of the cysteine-based DOPO-HQ comprises the following steps: adding 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide with a structural formula of , cysteine and p-toluenesulfonic acid into toluene, heating to 90-100 DEG C, condensing reflux reaction for 12-18 h, removing toluene by rotary evaporation, and separating the product by column chromatography to obtain the cysteine-based DOPO-HQ.

5. The flame-retardant modified PC-ABS plastic according to claim 4, characterized in that, The molar ratio of the 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, cysteine and p-toluenesulfonic acid is 1:(2.4-3.2):(0.3-0.4).

6. A process for the preparation of a flame-retardant modified PC-ABS plastic according to any one of claims 1-5, characterized in that, The preparation method comprises: mixing the PC resin, ABS resin, mercapto flame retardant, initiator and antioxidant, extruding in a double-screw extruder, cutting into particles, and then injection molding in an injection molding machine to obtain the fire-retardant modified PC-ABS plastic.

7. The process for preparing flame-retardant modified PC-ABS plastic according to claim 6, characterized in that, The temperature of each section of the double-screw extruder is 170-260℃, and the screw rotation speed is 150-250r / min.

8. The process for preparing flame retardant modified PC-ABS plastic according to claim 6, characterized in that, The temperature of each section of the injection molding machine is 180-265℃, and the pressure is 50-60MPa.

Images