PS flame retardant masterbatch and preparation method thereof

Abstract

The invention discloses a PS flame retardant masterbatch and a preparation method thereof, belonging to the technical field of flame retardant masterbatch. The preparation method comprises the following steps: preparing a first flame retardant, preparing a second flame retardant, mixing and granulating; the preparation of the first flame retardant comprises the following steps: preparing a mixed solution, preparing a cross-linked microsphere, preparing a magnesium hydroxide sol, compounding and silane modification; the preparation of the second flame retardant comprises the following steps: expansion, inclusion, intercalation and coating; the preparation method of the invention can improve the flame retardant property of a PS material prepared from the PS flame retardant masterbatch, and can also improve the transparency, anti-melting droplet property, mechanical strength and impact resistance of the PS material prepared from the PS flame retardant masterbatch, and reduce the smoke emission and thermal conductivity of the PS material prepared from the PS flame retardant masterbatch.

Description

Technical Field

[0001] The invention relates to the technical field of flame retardant masterbatches, and in particular to a PS flame retardant masterbatch and a preparation method thereof. Background Art

[0002] Polystyrene (PS) refers to a polymer synthesized from styrene monomers by free radical addition polymerization. The molecular chain is in a random configuration, and the side groups are benzene rings. PS has good transparency and a glass transition temperature above 100°C. It is light in weight, has good moisture resistance, insulation, and processing properties, and has a low thermal conductivity. It is widely used in packaging, home appliances, automobiles, construction, and other fields.

[0003] However, PS itself is flammable, and it will produce dripping and a lot of black smoke when burning, which limits the application of PS materials. Therefore, it is very necessary to improve the flame retardancy and smoke suppression of PS materials. At present, the main methods to improve the flame retardancy of PS materials are chemical modification of PS and adding flame retardants to PS materials. Chemical modification of PS, specifically using a melt extruder to graft PS, the grafting agent used is generally a grafting agent containing halogen elements, so that the PS material has flame retardant properties, but there is a problem of low grafting rate, and cross-linking will occur between the grafting agent and PS, affecting the transparency of the PS material. Therefore, the commonly used method to improve the flame retardancy of PS materials is to add flame retardants to PS.

[0004] The existing flame retardants used in PS materials mainly include halogen-containing flame retardants, intumescent flame retardants, and halogen-free flame retardants. Among them, halogen-containing flame retardants mainly include chlorine-based flame retardants and bromine-based flame retardants, which have the advantages of low addition amount and good flame retardant performance, but large smoke production; intumescent flame retardants are flame retardants with phosphorus and nitrogen as the main flame retardant elements. This type of flame retardant consists of three parts: acid source (dehydrating agent), carbon source (carbon forming agent), and gas source (foaming agent). It can reduce the smoke production of PS materials and improve the anti-melting droplet performance of PS materials, but the large addition amount will affect the transparency and thermal conductivity of PS materials; halogen-free flame retardants mainly include phosphorus-based flame retardants such as red phosphorus, phosphate esters, and phosphazenes, as well as metal hydroxides such as magnesium hydroxide and aluminum hydroxide. They have the advantages of good flame retardant performance and low smoke production, and are the most promising flame retardants.

[0005] However, when halogen-free flame retardants are added to PS materials as flame retardants, the following problems exist: the flame retardant principles of phosphorus-based flame retardants and metal hydroxides are similar, mainly including heat absorption effect, dilution of combustible gas, and formation of an isolation layer. Therefore, a high addition amount is required to achieve the effects of heat absorption, dilution, and isolation. Therefore, halogen-free flame retardants also have the disadvantage of high addition amount. In addition, halogen-free flame retardants also have the problems of poor dispersibility and poor compatibility with PS. As the addition amount increases, although the flame retardant properties of PS materials are improved, it will affect the transparency and thermal conductivity of PS materials, and will also affect the mechanical strength and impact resistance of PS materials.

[0006] In order to solve the above problems, the most commonly used method at present is to modify the surface of the halogen-free flame retardant, specifically, to graft the halogen-free flame retardant with a silane coupling agent or to coat the halogen-free flame retardant with a surfactant, thereby improving the dispersibility of the halogen-free flame retardant and the compatibility with PS, and further improving the mechanical strength and impact resistance of the PS material. However, there is still a problem of high addition amount, and therefore, it will still affect the transparency and thermal conductivity of the PS material. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention provides a PS flame retardant masterbatch and a preparation method thereof, which can improve the flame retardant properties of a PS material prepared from the PS flame retardant masterbatch, while also improving the transparency, anti-melting droplet performance, mechanical strength, and impact resistance of the PS material prepared from the PS flame retardant masterbatch, and reduce the smoke emission and thermal conductivity of the PS material prepared from the PS flame retardant masterbatch.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing a PS flame retardant masterbatch, comprising the following steps: preparing a first flame retardant, preparing a second flame retardant, mixing, and granulating;

[0010] The preparation of the first flame retardant comprises the following steps: preparing a mixed solution, preparing cross-linked microspheres, preparing a magnesium hydroxide sol, compounding, and silane modification;

[0011] The method for preparing the mixed solution comprises adding tannic acid and deionized water into a reaction kettle, controlling the temperature of the reaction kettle to 15-35° C., controlling the stirring speed to 200-300 rpm, stirring for 30-40 minutes, adding sodium carboxymethyl cellulose, stirring for 50-60 minutes, adding hydrochloric acid aqueous solution, stirring for 30-40 minutes, and obtaining a mixed solution;

[0012] In the prepared mixed solution, the mass ratio of tannic acid, deionized water, sodium carboxymethyl cellulose and hydrochloric acid aqueous solution is 150-160:1900-2000:115-125:100-110;

[0013] The molar concentration of the hydrochloric acid aqueous solution is 0.5 mol / L;

[0014] The method for preparing cross-linked microspheres comprises: adding a glutaraldehyde aqueous solution into a reaction kettle, controlling the temperature of the reaction kettle to 35-40° C., controlling the stirring speed to 400-500 rpm, dropping the mixed solution, continuing stirring for 3-3.5 hours after the dropping is completed, transferring the mixture into a centrifuge, controlling the centrifugal speed of the centrifuge to 9000-10000 rpm, centrifuging for 10-12 minutes, washing the precipitate with deionized water for 3-4 times, washing the precipitate with anhydrous ethanol for 3-4 times, and then vacuum drying at 70-80° C. to obtain cross-linked microspheres;

[0015] In the preparation of the cross-linked microspheres, the mass ratio of the glutaraldehyde aqueous solution to the mixed solution is 1000-1100:1000-1300;

[0016] The mass concentration of the glutaraldehyde aqueous solution is 5%;

[0017] The dropwise addition rate of the mixed solution is 14-15 g / min;

[0018] The method for preparing magnesium hydroxide sol comprises: adding magnesium chloride aqueous solution into a reaction kettle, controlling the temperature of the reaction kettle to 60-70° C., controlling the stirring speed to 100-200 rpm, dripping sodium hydroxide aqueous solution, and continuing to stir for 2-2.5 hours after the dripping is completed, to obtain magnesium hydroxide sol;

[0019] In the preparation of the magnesium hydroxide sol, the mass ratio of the magnesium chloride aqueous solution to the sodium hydroxide aqueous solution is 450-470:450-500;

[0020] The mass concentration of the magnesium chloride aqueous solution is 20%;

[0021] The mass concentration of the sodium hydroxide aqueous solution is 8%;

[0022] The dropping speed of the sodium hydroxide aqueous solution is 6-8g / min;

[0023] The composite method comprises the following steps: adding cross-linked microspheres and deionized water into a reaction kettle, controlling the temperature of the reaction kettle to 15-35° C., controlling the stirring speed to 100-200 rpm, dropping magnesium hydroxide sol, continuing stirring for 1.5-2 hours after the dropping is completed, transferring the mixture into a centrifuge, controlling the centrifugal speed of the centrifuge to 8000-9000 rpm, centrifuging for 10-12 minutes, washing the precipitate with deionized water for 3-4 times, and then vacuum drying at 70-80° C. to obtain composite microspheres;

[0024] In the composite, the mass ratio of the cross-linked microspheres, deionized water, and magnesium hydroxide sol is 100-110:700-800:3400-3500;

[0025] The dropping speed of the magnesium hydroxide sol is 17-20 g / min;

[0026] The silane modification method comprises the following steps: adding composite microspheres, anhydrous ethanol and deionized water into a reaction kettle, controlling the temperature of the reaction kettle to 40-50° C., controlling the stirring speed to 50-100 rpm, stirring for 20-30 min, adding ammonia water, methyltrimethoxysilane and phenyltrimethoxysilane, stirring for 5-6 h, transferring the mixture into a centrifuge, controlling the centrifugal speed of the centrifuge to 8000-9000 rpm, centrifuging for 10-12 min, washing the precipitate with anhydrous ethanol for 3-4 times, and then vacuum drying the mixture at 70-80° C. to obtain a first flame retardant;

[0027] In the silane modification, the mass ratio of the composite microspheres, anhydrous ethanol, deionized water, ammonia water, methyltrimethoxysilane and phenyltrimethoxysilane is 150-160:3000-3200:30-35:300-350:50-55:20-25;

[0028] The mass concentration of the ammonia water is 25%;

[0029] The preparation of the second flame retardant comprises the following steps: expansion, inclusion, intercalation, and coating;

[0030] The expansion method comprises the following steps: adding nano-montmorillonite, deionized water and sodium dodecylbenzene sulfonate into a reaction kettle, controlling the temperature of the reaction kettle to 30-45° C., controlling the stirring speed to 300-400 rpm, stirring for 2-3 hours, transferring the reaction kettle into a centrifuge, controlling the centrifugal speed of the centrifuge to 8000-9000 rpm, centrifuging for 10-12 minutes, washing the precipitate with deionized water for 3-4 times, and then vacuum drying at 70-80° C. to obtain expanded nano-montmorillonite;

[0031] During the expansion, the mass ratio of nano-montmorillonite, deionized water, and sodium dodecylbenzene sulfonate is 100-110:1000-1300:3-4;

[0032] The particle size of the nano-montmorillonite is 100 nm;

[0033] The inclusion method comprises the following steps: adding methyl octabromoether and acetone into a reaction kettle, controlling the temperature of the reaction kettle to 15-40°C, controlling the stirring speed to 300-400 rpm, stirring for 20-30 min, and obtaining a methyl octabromoether solution; adding β-cyclodextrin and deionized water into a reaction kettle, controlling the temperature of the reaction kettle to 15-40°C, controlling the stirring speed to 100-200 rpm, stirring for 20-30 min, dripping the methyl octabromoether solution, stirring for 4-5 h after the dripping is completed, standing for 12-15 h, removing the acetone by evaporation under reduced pressure, filtering, and freeze-drying the filtrate at -40°C to -35°C to obtain inclusion cyclodextrin;

[0034] In the inclusion, the mass ratio of methyl octabromoether, acetone, β-cyclodextrin and deionized water is 4-4.5:28-30:40-45:2800-3000;

[0035] The dropping speed of the methyl octabromoether solution is 2-3 g / min;

[0036] The intercalation method comprises the following steps: adding the inclusion cyclodextrin and the first portion of deionized water into a reactor, controlling the temperature of the reactor to 15-40°C, controlling the stirring speed to 300-400 rpm, stirring for 20-30 minutes, and obtaining the inclusion cyclodextrin dispersion; adding the expanded nano-montmorillonite and the second portion of deionized water into the reactor, controlling the temperature of the reactor to 45-55°C, controlling the stirring speed to 300-400 rpm, stirring for 20-30 minutes, dripping the inclusion cyclodextrin dispersion, stirring for 60-80 minutes after the dripping, dripping the glutaraldehyde aqueous solution, continuing to stir for 60-80 minutes after the dripping, transferring the mixture into a centrifuge, controlling the centrifugal speed of the centrifuge to 8000-9000 rpm, centrifuging for 10-12 minutes, washing the precipitate 3-4 times with deionized water, and then freeze-drying the mixture at -40°C to -35°C to obtain the intercalated montmorillonite;

[0037] In the intercalation layer, the mass ratio of the inclusion cyclodextrin, the first portion of deionized water, the expanded nano-montmorillonite, the second portion of deionized water, and the glutaraldehyde aqueous solution is 40-50:4000-5000:90-100:2000-2500:70-80;

[0038] The mass concentration of the glutaraldehyde aqueous solution is 5%;

[0039] The dropwise addition rate of the cyclodextrin inclusion dispersion is 40-50 g / min;

[0040] The dropping speed of the glutaraldehyde aqueous solution is 4-5 g / min;

[0041] The coating method comprises adding intercalated montmorillonite, cyclodextrin and deionized water into a reactor, controlling the temperature of the reactor to 15-40° C., controlling the stirring speed to 100-200 rpm, stirring for 40-60 min, transferring the reactor into a centrifuge, controlling the centrifugal speed of the centrifuge to 8000-9000 rpm, centrifuging for 10-12 min, washing the precipitate with deionized water for 3-4 times, and then freeze-drying the precipitate at -40° C. to -35° C. to obtain a second flame retardant;

[0042] In the coating, the mass ratio of intercalated montmorillonite, cyclodextrin and deionized water is 50-55:100-120:7500-8000;

[0043] The mixing method comprises adding polystyrene particles, a first flame retardant, a second flame retardant, an antioxidant 1010, and calcium stearate into a high-speed mixer, controlling the speed of the high-speed mixer to 900-1100 rpm, and mixing at a high speed for 2-3 minutes to obtain a mixture;

[0044] In the mixture, the mass ratio of polystyrene particles, the first flame retardant, the second flame retardant, the antioxidant 1010, and calcium stearate is 70-78:20-25:10-15:0.3-0.4:0.3-0.5;

[0045] The polystyrene particles have a degree of polymerization of 3000 and a melt index of 6 g / 10 min at 200° C. and 5 kg;

[0046] The granulation method comprises the following steps: adding the mixed material into a twin-screw extruder for granulation, controlling the screw speed of the twin-screw extruder to be 300-350 rpm, controlling the temperature of the first zone to be 180-185° C., the temperature of the second zone to be 185-190° C., the temperature of the third zone to be 190-195° C., the temperature of the fourth zone to be 195-200° C., the temperature of the fifth zone to be 200-205° C., the temperature of the sixth zone to be 205-210° C., the temperature of the seventh zone to be 200-205° C., and the temperature of the die head to be 205-210° C., so as to obtain PS flame retardant masterbatch.

[0047] A PS flame retardant masterbatch prepared by the above-mentioned preparation method.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) The preparation method of PS flame retardant masterbatch of the present invention includes adding a first flame retardant and a second flame retardant during the preparation of PS flame retardant masterbatch. When preparing the first flame retardant, tannic acid and sodium carboxymethyl cellulose are first mixed, and then cross-linked using glutaraldehyde as a cross-linking agent to obtain cross-linked microspheres, wherein sodium carboxymethyl cellulose increases the cross-linking of hydroxyl groups with tannic acid while providing negative charge, and then magnesium hydroxide sol with positive charge is added, and the magnesium hydroxide sol is firmly adsorbed on the surface of the cross-linked microspheres through electrostatic action and hydrogen bonding to obtain composite microspheres; finally, methyltrimethoxysilane and phenyltrimethoxysilane are used to perform silane modification on the composite microspheres, and hydrophobic groups are introduced on the surface of the composite microspheres to obtain the first flame retardant with a porous structure. Among them, tannic acid is used as a flame retardant, and its flame retardant mechanism is to quench free radicals to form a dense carbon layer. It can play a synergistic role with magnesium hydroxide to form a dense isolation layer, thereby reducing the dosage of magnesium hydroxide and improving the oxygen index and monomer combustion test results of the PS flame retardant; the hydrophobic groups introduced on the surface of the composite microspheres can improve the dispersibility of the first flame retardant and its compatibility with polystyrene, and improve the transparency, mechanical strength and impact resistance of the PS flame retardant masterbatch; the porous structure of the first flame retardant is conducive to promoting foaming and reducing the thermal conductivity of the PS flame retardant masterbatch. When preparing the second flame retardant, sodium dodecylbenzene sulfonate is first used to expand the nano-montmorillonite to increase the interlayer distance of the montmorillonite, and then β-cyclodextrin is used to encapsulate methyl octabromoether to obtain encapsulated cyclodextrin, thereby fixing methyl octabromoether and improving the dispersibility of methyl octabromoether, and then the expanded montmorillonite is intercalated with the encapsulated cyclodextrin, and glutaraldehyde is used as a cross-linking agent to fix the β-cyclodextrin encapsulated with methyl octabromoether between the layers of the montmorillonite to obtain intercalated montmorillonite, thereby adsorbing the smoke generated by methyl octabromoether, reducing the smoke emission, and thus improving the monomer combustion test of polystyrene. The results of the experiment were obtained; finally, the intercalated montmorillonite was coated with cyclodextrin; firstly, the dispersibility of the intercalated montmorillonite and its compatibility with the PS flame retardant masterbatch can be improved, thereby improving the transparency, mechanical strength and impact resistance of the PS masterbatch; secondly, cyclodextrin can act as a nucleating agent, which can promote PS nucleation while reducing the size of spherulites, thereby further improving the mechanical strength and impact resistance of the PS flame retardant masterbatch and avoiding affecting the transparency of the PS flame retardant masterbatch; thirdly, the cavity of the coated cyclodextrin can promote foaming and reduce the thermal conductivity of the PS flame retardant masterbatch;

[0050] (2) The oxygen index of the PS material prepared by the PS flame retardant masterbatch of the present invention is 37-38%;

[0051] (3) The light transmittance of the PS material prepared by the PS flame retardant masterbatch of the present invention is 87.7-88.5%;

[0052] (4) The tensile strength of the PS material prepared by the PS flame retardant masterbatch of the present invention is 47.0-47.8 MPa;

[0053] (5) The Charpy impact strength of the PS material prepared from the PS flame retardant masterbatch of the present invention is 4.8-5.1 kJ / m 2 ;

[0054] (6) The thermal conductivity of the PS material prepared by the PS flame retardant masterbatch of the present invention is 0.034-0.037 W / (m·K);

[0055] (7) The PS material prepared by the PS flame retardant masterbatch of the present invention has good anti-melting droplet performance and low smoke emission. The results of the monomer combustion test are: FIGRA 0.4J 0W / s, THR 600s 0.11-0.15MJ, LPS is smaller than the edge of the sample, SMOGRA is 6-7m 2 / s 2 ,TSP 600s 21-24m 2 , no burning drops / particles are generated within 600s to meet the requirements. DETAILED DESCRIPTION

[0056] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation methods of the present invention are now described.

[0057] Example 1

[0058] A method for preparing PS flame retardant masterbatch, specifically comprising:

[0059] 1. Preparation of the first flame retardant:

[0060] (1) Preparing a mixed solution: adding 150 g of tannic acid and 1900 g of deionized water into a reactor, controlling the temperature of the reactor to 15° C., controlling the stirring speed to 200 rpm, stirring for 30 min, adding 115 g of sodium carboxymethyl cellulose, stirring for 50 min, adding 100 g of a hydrochloric acid aqueous solution with a molar concentration of 0.5 mol / L, stirring for 30 min, and obtaining a mixed solution;

[0061] (2) Preparation of cross-linked microspheres: Add 1000 g of 5% glutaraldehyde aqueous solution into a reactor, control the temperature of the reactor to 35°C, control the stirring speed to 400 rpm, add 1000 g of the mixed solution dropwise, control the dropping speed to 14 g / min, continue stirring for 3 h after the addition is completed, transfer to a centrifuge, control the centrifugal speed of the centrifuge to 9000 rpm, centrifuge for 10 min, wash the precipitate 3 times with deionized water, wash the precipitate 3 times with anhydrous ethanol, and then vacuum dry at 70°C to obtain cross-linked microspheres;

[0062] (3) Preparation of magnesium hydroxide sol: 450 g of a 20% magnesium chloride aqueous solution was added to a reactor, the temperature of the reactor was controlled to 60° C., the stirring speed was controlled to 100 rpm, 450 g of an 8% sodium hydroxide aqueous solution was added dropwise, the dropping speed was controlled to 6 g / min, and stirring was continued for 2 h after the addition was completed to obtain magnesium hydroxide sol;

[0063] (4) Compounding: 100 g of cross-linked microspheres and 700 g of deionized water were added to a reactor, the temperature of the reactor was controlled to 15°C, the stirring speed was controlled to 100 rpm, 3400 g of magnesium hydroxide sol was added dropwise, and the dropping speed was controlled to 17 g / min. After the addition was completed, stirring was continued for 1.5 h, and the mixture was transferred to a centrifuge, and the centrifugal speed of the centrifuge was controlled to 8000 rpm. Centrifugation was performed for 10 min, and the precipitate was washed 3 times with deionized water, and then vacuum dried at 70°C to obtain composite microspheres;

[0064] (5) Silane modification: 150 g of composite microspheres, 3000 g of anhydrous ethanol, and 30 g of deionized water were added to a reactor, the temperature of the reactor was controlled to 40°C, the stirring speed was controlled to 50 rpm, and the mixture was stirred for 20 min. 300 g of 25% ammonia water, 50 g of methyltrimethoxysilane, and 20 g of phenyltrimethoxysilane were added, and the mixture was stirred for 5 h. The mixture was transferred to a centrifuge, the centrifugal speed of the centrifuge was controlled to 8000 rpm, and the mixture was centrifuged for 10 min. The precipitate was washed three times with anhydrous ethanol, and then vacuum dried at 70°C to obtain a first flame retardant.

[0065] 2. Preparation of the second flame retardant:

[0066] (1) Expansion: 100 g of nano-montmorillonite, 1000 g of deionized water, and 3 g of sodium dodecylbenzene sulfonate were added to a reactor, the temperature of the reactor was controlled to 30° C., the stirring speed was controlled to 300 rpm, and the mixture was stirred for 2 h. The mixture was transferred to a centrifuge, the centrifugal speed of the centrifuge was controlled to 8000 rpm, and the mixture was centrifuged for 10 min. The precipitate was washed 3 times with deionized water, and then vacuum dried at 70° C. to obtain expanded nano-montmorillonite.

[0067] The particle size of the nano-montmorillonite is 100 nm;

[0068] (2) Inclusion: Add 4 g of methyl octabromoether and 28 g of acetone to a reactor, control the temperature of the reactor to 15°C, control the stirring speed to 300 rpm, and stir for 20 min to obtain a methyl octabromoether solution; add 40 g of β-cyclodextrin and 2800 g of deionized water to a reactor, control the temperature of the reactor to 15°C, control the stirring speed to 100 rpm, and stir for 20 min, then dropwise add all of the above methyl octabromoether solution, control the dropping speed to 2 g / min, stir for 4 h after the dropwise addition, let stand for 12 h, evaporate the acetone under reduced pressure, filter, and freeze-dry the filtrate at -40°C to obtain inclusion cyclodextrin;

[0069] (3) Intercalation: 40 g of cyclodextrin inclusion and 4000 g of deionized water were added to a reactor, the temperature of the reactor was controlled to 15°C, the stirring speed was controlled to 300 rpm, and the mixture was stirred for 20 min to obtain a cyclodextrin inclusion dispersion; 90 g of expanded nano-montmorillonite and 2000 g of deionized water were added to a reactor, the temperature of the reactor was controlled to 45°C, the stirring speed was controlled to 300 rpm, and the mixture was stirred for 20 min. The above-mentioned cyclodextrin inclusion dispersion was added dropwise at a rate of 40 g / min, and the mixture was stirred for 60 min after the addition was completed. 70 g of a 5% glutaraldehyde aqueous solution was added dropwise at a rate of 4 g / min, and the mixture was stirred for 60 min after the addition was completed. The mixture was transferred to a centrifuge, the centrifugal speed of the centrifuge was controlled to 8000 rpm, and the mixture was centrifuged for 10 min. The precipitate was washed three times with deionized water, and then freeze-dried at -40°C to obtain intercalated montmorillonite.

[0070] (4) Coating: 50 g of intercalated montmorillonite, 100 g of cyclodextrin, and 7500 g of deionized water were added to a reactor, the temperature of the reactor was controlled to 15°C, the stirring speed was controlled to 100 rpm, and the mixture was stirred for 40 min. The mixture was transferred to a centrifuge, the centrifugal speed of the centrifuge was controlled to 8000 rpm, and the mixture was centrifuged for 10 min. The precipitate was washed three times with deionized water, and then freeze-dried at -40°C to obtain a second flame retardant.

[0071] 3. Mixing: Add polystyrene particles, the first flame retardant, the second flame retardant, antioxidant 1010, and calcium stearate in a mass ratio of 70:20:10:0.3:0.3 into a high-speed mixer, control the speed of the high-speed mixer to 900 rpm, and mix at high speed for 2 minutes to obtain a mixture;

[0072] The polystyrene particles have a degree of polymerization of 3000 and a melt index of 6 g / 10 min at 200° C. and 5 kg;

[0073] 4. Granulation: Add the mixed material into a twin-screw extruder for granulation, control the screw speed of the twin-screw extruder to 300rpm, the temperature of zone 1 to 180℃, the temperature of zone 2 to 185℃, the temperature of zone 3 to 190℃, the temperature of zone 4 to 195℃, the temperature of zone 5 to 200℃, the temperature of zone 6 to 205℃, the temperature of zone 7 to 200℃, and the temperature of the die to 205℃ to obtain PS flame retardant masterbatch.

[0074] This embodiment also provides a PS flame retardant masterbatch prepared by the aforementioned preparation method.

[0075] Example 2

[0076] A method for preparing PS flame retardant masterbatch, specifically comprising:

[0077] 1. Preparation of the first flame retardant:

[0078] (1) Preparing a mixed solution: adding 155 g of tannic acid and 1950 g of deionized water into a reactor, controlling the temperature of the reactor to 25° C., controlling the stirring speed to 250 rpm, stirring for 35 min, adding 120 g of sodium carboxymethyl cellulose, stirring for 55 min, adding 105 g of a 0.5 mol / L aqueous hydrochloric acid solution, stirring for 35 min, and obtaining a mixed solution;

[0079] (2) Preparation of cross-linked microspheres: 1050 g of 5% glutaraldehyde aqueous solution was added to a reactor, the temperature of the reactor was controlled to 38°C, the stirring speed was controlled to 450 rpm, 1200 g of the mixed solution was added dropwise, the dropping speed was controlled to 14 g / min, stirring was continued for 3 h after the addition was completed, the mixture was transferred to a centrifuge, the centrifugal speed of the centrifuge was controlled to 9500 rpm, centrifuged for 11 min, the precipitate was washed 3 times with deionized water, the precipitate was washed 3 times with anhydrous ethanol, and then vacuum dried at 75°C to obtain cross-linked microspheres;

[0080] (3) Preparation of magnesium hydroxide sol: 460 g of a 20% magnesium chloride aqueous solution was added to a reactor, the temperature of the reactor was controlled to 65° C., the stirring speed was controlled to 150 rpm, 480 g of an 8% sodium hydroxide aqueous solution was added dropwise, the dropping speed was controlled to 7 g / min, and stirring was continued for 2 h after the addition was completed to obtain magnesium hydroxide sol;

[0081] (4) Compounding: 105 g of cross-linked microspheres and 750 g of deionized water were added to a reactor, the temperature of the reactor was controlled to 25 ° C, the stirring speed was controlled to 150 rpm, 3450 g of magnesium hydroxide sol was added dropwise, and the dropping speed was controlled to 18 g / min. After the addition was completed, stirring was continued for 1.5 h, and the mixture was transferred to a centrifuge, and the centrifugal speed of the centrifuge was controlled to 8500 rpm. Centrifugation was performed for 11 min, and the precipitate was washed with deionized water for 3-4 times, and then vacuum dried at 75 ° C to obtain composite microspheres;

[0082] (5) Silane modification: 155 g of composite microspheres, 3100 g of anhydrous ethanol, and 32 g of deionized water were added to a reactor, the temperature of the reactor was controlled to 45 ° C, the stirring speed was controlled to 80 rpm, and the stirring was carried out for 25 min. 320 g of ammonia water with a mass concentration of 25%, 52 g of methyltrimethoxysilane, and 22 g of phenyltrimethoxysilane were added, and the mixture was stirred for 5.5 h. The mixture was transferred to a centrifuge, the centrifugal speed of the centrifuge was controlled to 8500 rpm, and the mixture was centrifuged for 11 min. The precipitate was washed 3 times with anhydrous ethanol, and then vacuum dried at 75 ° C to obtain a first flame retardant.

[0083] 2. Preparation of the second flame retardant:

[0084] (1) Expansion: 105 g of nano-montmorillonite, 1200 g of deionized water, and 3.5 g of sodium dodecylbenzene sulfonate were added to a reactor, the temperature of the reactor was controlled to 40°C, the stirring speed was controlled to 350 rpm, and the stirring was performed for 2.5 h. The reactor was transferred to a centrifuge, the centrifugal speed of the centrifuge was controlled to 8500 rpm, and the centrifugation was performed for 11 min. The precipitate was washed 3 times with deionized water, and then vacuum dried at 75°C to obtain expanded nano-montmorillonite.

[0085] The particle size of the nano-montmorillonite is 100 nm;

[0086] (2) Inclusion: 4.2 g of methyl octabromoether and 29 g of acetone were added to a reactor, the temperature of the reactor was controlled to 25°C, the stirring speed was controlled to 350 rpm, and the mixture was stirred for 25 min to obtain a methyl octabromoether solution; 42 g of β-cyclodextrin and 2900 g of deionized water were added to a reactor, the temperature of the reactor was controlled to 25°C, the stirring speed was controlled to 150 rpm, and the mixture was stirred for 25 min. The above-mentioned methyl octabromoether solution was added dropwise at a dropping rate of 2.5 g / min. After the addition was completed, the mixture was stirred for 4.5 h, and the mixture was allowed to stand for 14 h. After evaporation under reduced pressure to remove the acetone, the mixture was filtered, and the filtrate was freeze-dried at -40°C to obtain inclusion cyclodextrin;

[0087] (3) Intercalation: 45 g of cyclodextrin inclusion and 4500 g of deionized water were added to a reactor, the temperature of the reactor was controlled to 25°C, the stirring speed was controlled to 350 rpm, and the mixture was stirred for 25 min to obtain a cyclodextrin inclusion dispersion; 95 g of expanded nano-montmorillonite and 2200 g of deionized water were added to a reactor, the temperature of the reactor was controlled to 50°C, the stirring speed was controlled to 350 rpm, and the mixture was stirred for 25 min. All of the above cyclodextrin inclusion dispersion was added dropwise at a rate of 45 g / min. After the addition was completed, the mixture was stirred for 70 min. 75 g of a 5% glutaraldehyde aqueous solution was added dropwise at a rate of 4 g / min. After the addition was completed, the mixture was stirred for 70 min. The mixture was transferred to a centrifuge, the centrifugal speed of the centrifuge was controlled to 8500 rpm, and the mixture was centrifuged for 11 min. The precipitate was washed three times with deionized water, and then freeze-dried at -40°C to obtain intercalated montmorillonite.

[0088] (4) Coating: 52 g of intercalated montmorillonite, 110 g of cyclodextrin, and 7800 g of deionized water were added to a reactor, the temperature of the reactor was controlled to 25°C, the stirring speed was controlled to 150 rpm, and the mixture was stirred for 50 min. The mixture was transferred to a centrifuge, the centrifugal speed of the centrifuge was controlled to 8500 rpm, and the mixture was centrifuged for 11 min. The precipitate was washed three times with deionized water, and then freeze-dried at -40°C to obtain a second flame retardant.

[0089] 3. Mixing: Add polystyrene particles, the first flame retardant, the second flame retardant, antioxidant 1010, and calcium stearate in a mass ratio of 75:22:13:0.3:0.4 into a high-speed mixer, control the speed of the high-speed mixer to 1000 rpm, and mix at high speed for 2.5 minutes to obtain a mixture;

[0090] The polystyrene particles have a degree of polymerization of 3000 and a melt index of 6 g / 10 min at 200° C. and 5 kg;

[0091] 4. Granulation: Add the mixed material into a twin-screw extruder for granulation, control the screw speed of the twin-screw extruder to 320rpm, the temperature of zone 1 to 180℃, the temperature of zone 2 to 185℃, the temperature of zone 3 to 190℃, the temperature of zone 4 to 195℃, the temperature of zone 5 to 200℃, the temperature of zone 6 to 205℃, the temperature of zone 7 to 200℃, and the temperature of the die to 205℃ to obtain PS flame retardant masterbatch.

[0092] This embodiment also provides a PS flame retardant masterbatch prepared by the aforementioned preparation method.

[0093] Example 3

[0094] A method for preparing PS flame retardant masterbatch, specifically comprising:

[0095] 1. Preparation of the first flame retardant:

[0096] (1) Preparing a mixed solution: adding 160 g of tannic acid and 2000 g of deionized water into a reactor, controlling the temperature of the reactor to 35° C., controlling the stirring speed to 300 rpm, stirring for 40 min, adding 125 g of sodium carboxymethyl cellulose, stirring for 60 min, adding 110 g of a hydrochloric acid aqueous solution with a molar concentration of 0.5 mol / L, stirring for 40 min, and obtaining a mixed solution;

[0097] (2) Preparation of cross-linked microspheres: 1100 g of 5% glutaraldehyde aqueous solution was added to a reactor, the temperature of the reactor was controlled to 40°C, the stirring speed was controlled to 500 rpm, 1300 g of the mixed solution was added dropwise, the dropping speed was controlled to 15 g / min, stirring was continued for 3.5 h after the addition was completed, the mixture was transferred to a centrifuge, the centrifugal speed of the centrifuge was controlled to 10000 rpm, centrifuged for 12 min, the precipitate was washed with deionized water for 3-4 times, the precipitate was washed with anhydrous ethanol for 4 times, and then vacuum dried at 80°C to obtain cross-linked microspheres;

[0098] (3) Preparation of magnesium hydroxide sol: 470 g of a 20% magnesium chloride aqueous solution was added to a reactor, the temperature of the reactor was controlled to 70° C., the stirring speed was controlled to 200 rpm, 500 g of an 8% sodium hydroxide aqueous solution was added dropwise, the dropping speed was controlled to 8 g / min, and stirring was continued for 2.5 h after the addition was completed to obtain magnesium hydroxide sol;

[0099] (4) Compounding: 110 g of cross-linked microspheres and 800 g of deionized water were added to a reactor, the temperature of the reactor was controlled to 35°C, the stirring speed was controlled to 200 rpm, 3500 g of magnesium hydroxide sol was added dropwise, and the dropping speed was controlled to 20 g / min. After the addition was completed, stirring was continued for 2 h, and the mixture was transferred to a centrifuge, and the centrifugal speed of the centrifuge was controlled to 9000 rpm. Centrifugation was performed for 12 min, and the precipitate was washed 4 times with deionized water, and then vacuum dried at 80°C to obtain composite microspheres;

[0100] (5) Silane modification: 160 g of composite microspheres, 3200 g of anhydrous ethanol, and 35 g of deionized water were added to a reactor, the temperature of the reactor was controlled to 50°C, the stirring speed was controlled to 100 rpm, and the stirring was carried out for 30 min. 350 g of ammonia water with a mass concentration of 25%, 55 g of methyltrimethoxysilane, and 25 g of phenyltrimethoxysilane were added, and the mixture was stirred for 6 h. The mixture was transferred to a centrifuge, the centrifugal speed of the centrifuge was controlled to 9000 rpm, and the mixture was centrifuged for 12 min. The precipitate was washed 4 times with anhydrous ethanol, and then vacuum dried at 80°C to obtain a first flame retardant.

[0101] 2. Preparation of the second flame retardant:

[0102] (1) Expansion: 110 g of nano-montmorillonite, 1300 g of deionized water, and 4 g of sodium dodecylbenzene sulfonate were added to a reactor, the temperature of the reactor was controlled to 45° C., the stirring speed was controlled to 300-400 rpm, and the mixture was stirred for 3 h. The mixture was transferred to a centrifuge, the centrifugal speed of the centrifuge was controlled to 9000 rpm, and the mixture was centrifuged for 12 min. The precipitate was washed 4 times with deionized water, and then vacuum dried at 80° C. to obtain expanded nano-montmorillonite.

[0103] The particle size of the nano-montmorillonite is 100 nm;

[0104] (2) Inclusion: Add 4.5 g of methyl octabromoether and 30 g of acetone to a reactor, control the temperature of the reactor to 40°C, control the stirring speed to 400 rpm, and stir for 30 min to obtain a methyl octabromoether solution; add 45 g of β-cyclodextrin and 3000 g of deionized water to a reactor, control the temperature of the reactor to 40°C, control the stirring speed to 200 rpm, and stir for 30 min, then dropwise add all of the above methyl octabromoether solution, control the dropping speed to 3 g / min, stir for 5 h after the addition is completed, let stand for 15 h, evaporate under reduced pressure to remove acetone, filter, and freeze-dry the filtrate at -35°C to obtain inclusion cyclodextrin;

[0105] (3) Intercalation: 50 g of cyclodextrin inclusion and 5000 g of deionized water were added to a reactor, the temperature of the reactor was controlled to 40°C, the stirring speed was controlled to 400 rpm, and the mixture was stirred for 30 min to obtain a cyclodextrin inclusion dispersion; 100 g of expanded nano-montmorillonite and 2500 g of deionized water were added to a reactor, the temperature of the reactor was controlled to 55°C, the stirring speed was controlled to 400 rpm, and the mixture was stirred for 30 min. The above-mentioned cyclodextrin inclusion dispersion was added dropwise at a rate of 50 g / min, and the mixture was stirred for 80 min after the addition was completed. 80 g of a 5% glutaraldehyde aqueous solution was added dropwise at a rate of 5 g / min, and the mixture was stirred for 80 min after the addition was completed. The mixture was transferred to a centrifuge, the centrifugal speed of the centrifuge was controlled to 9000 rpm, and the mixture was centrifuged for 12 min. The precipitate was washed 4 times with deionized water, and then freeze-dried at -35°C to obtain intercalated montmorillonite;

[0106] (4) Coating: 55 g of intercalated montmorillonite, 120 g of cyclodextrin, and 8000 g of deionized water were added to a reactor, the temperature of the reactor was controlled to 40°C, the stirring speed was controlled to 200 rpm, and the stirring was performed for 60 min. The reactor was transferred to a centrifuge, the centrifugal speed of the centrifuge was controlled to 9000 rpm, and the centrifugation was performed for 12 min. The precipitate was washed 4 times with deionized water, and then freeze-dried at -35°C to obtain a second flame retardant.

[0107] 3. Mixing: Add polystyrene particles, the first flame retardant, the second flame retardant, antioxidant 1010, and calcium stearate in a mass ratio of 78:25:15:0.4:0.5 into a high-speed mixer, control the speed of the high-speed mixer to 1100 rpm, and mix at high speed for 3 minutes to obtain a mixture;

[0108] The polystyrene particles have a degree of polymerization of 3000 and a melt index of 6 g / 10 min at 200° C. and 5 kg;

[0109] 4. Granulation: Add the mixed material into a twin-screw extruder for granulation, control the screw speed of the twin-screw extruder to 350rpm, the temperature of zone 1 to 185℃, the temperature of zone 2 to 190℃, the temperature of zone 3 to 195℃, the temperature of zone 4 to 200℃, the temperature of zone 5 to 205℃, the temperature of zone 6 to 210℃, the temperature of zone 7 to 205℃, and the temperature of the die to 210℃ to obtain PS flame retardant masterbatch.

[0110] This embodiment also provides a PS flame retardant masterbatch prepared by the aforementioned preparation method.

[0111] Comparative Example 1

[0112] On the basis of Example 2, the first step of preparing the first flame retardant is omitted, and in the third step, an equal amount of 1 μm magnesium hydroxide is used in the mixing to replace the addition of the first flame retardant.

[0113] The remaining operations are the same as those in Example 2.

[0114] This comparative example also provides a PS flame retardant masterbatch prepared by the aforementioned preparation method.

[0115] Comparative Example 2

[0116] On the basis of Example 2, the second step of preparing the second flame retardant was omitted, and in the third step, an equal amount of methyl octabromoether was used in the mixture to replace the addition of the second flame retardant.

[0117] The remaining operations are the same as those in Example 2.

[0118] This comparative example also provides a PS flame retardant masterbatch prepared by the aforementioned preparation method.

[0119] Test example

[0120] The PS flame retardant masterbatch of Examples 1-3 and Comparative Examples 1-2 was respectively added to a twin-screw extruder, and N,N'-dinitrosopentamethylenetetramine was injected, and the mass ratio of the PS flame retardant masterbatch to N,N'-dinitrosopentamethylenetetramine was controlled to be 100:4, the injection pressure was 10kPa, the temperature of the first zone of the twin-screw extruder was 190°C, the temperature of the second zone was 195°C, the temperature of the third zone was 200°C, the temperature of the fourth zone was 205°C, the temperature of the fifth zone was 205°C, the temperature of the sixth zone was 210°C, the temperature of the seventh zone was 205°C, and the head temperature was 210°C, and then transferred to a molding machine for pressing into a polystyrene foam board with a thickness of 20 cm, and then the limiting oxygen index, transparency, tensile strength, Charpy impact strength, and thermal conductivity of the polystyrene foam board were tested, and the test results were as follows:

[0121]

[0122] Furthermore, a single combustion test was conducted on the polystyrene foam board, and the test results are as follows:

[0123]

[0124] It can be seen from the above results that by adding the first flame retardant to the PS flame retardant masterbatch, the thermal conductivity of the PS material prepared from the PS flame retardant masterbatch can be reduced, the oxygen index, light transmittance, tensile strength, and Charpy impact strength of the PS material prepared from the PS flame retardant masterbatch can be improved, and the monomer combustion test results of the PS material prepared from the PS flame retardant masterbatch can be improved;

[0125] By adding a second flame retardant to the PS flame retardant masterbatch, the thermal conductivity of the PS material prepared from the PS flame retardant masterbatch can be reduced, the light transmittance, tensile strength, and Charpy impact strength of the PS material prepared from the PS flame retardant masterbatch can be improved, and the monomer combustion test results of the PS material prepared from the PS flame retardant masterbatch can be improved.

[0126] Unless otherwise specified, all percentages used in the present invention are by mass.

[0127] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing PS flame retardant masterbatch, It is characterized in that The method comprises the following steps: preparing a first flame retardant, preparing a second flame retardant, mixing, and granulating; The preparation of the first flame retardant comprises the following steps: preparing a mixed solution, preparing cross-linked microspheres, preparing a magnesium hydroxide sol, compounding, and silane modification; The method for preparing the mixed solution is to mix tannic acid and deionized water, stir at 15-35° C., add sodium carboxymethyl cellulose, stir, add hydrochloric acid aqueous solution, stir to obtain a mixed solution; In the prepared mixed solution, the mass ratio of tannic acid, deionized water, sodium carboxymethyl cellulose and aqueous hydrochloric acid solution is 150-160:1900-2000:115-125:100-110; The method for preparing cross-linked microspheres comprises stirring a glutaraldehyde aqueous solution at 35-40° C., then dropping the mixed solution into the glutaraldehyde aqueous solution, continuing to stir after the dropping is completed, centrifuging, washing, and vacuum drying the precipitate to obtain cross-linked microspheres; In the preparation of the cross-linked microspheres, the mass ratio of the glutaraldehyde aqueous solution to the mixed solution is 1000-1100:1000-1300; The method for preparing the magnesium hydroxide sol comprises: stirring a magnesium chloride aqueous solution at 60-70° C., then dripping a sodium hydroxide aqueous solution into the magnesium chloride aqueous solution, and continuing to stir after the dripping is completed to obtain the magnesium hydroxide sol; In the preparation of the magnesium hydroxide sol, the mass ratio of the magnesium chloride aqueous solution to the sodium hydroxide aqueous solution is 450-470:450-500; The composite method comprises mixing cross-linked microspheres and deionized water, stirring at 15-35° C., dropping magnesium hydroxide sol, continuing stirring after the dropping, centrifuging, washing, and vacuum drying the precipitate to obtain composite microspheres; In the composite, the mass ratio of the cross-linked microspheres, deionized water, and magnesium hydroxide sol is 100-110:700-800:3400-3500; The silane modification method comprises mixing composite microspheres, anhydrous ethanol and deionized water, stirring at 40-50° C., adding ammonia water, methyltrimethoxysilane and phenyltrimethoxysilane, stirring, centrifuging, washing and vacuum drying the precipitate to obtain a first flame retardant; In the silane modification, the mass ratio of the composite microspheres, anhydrous ethanol, deionized water, ammonia water, methyltrimethoxysilane and phenyltrimethoxysilane is 150-160:3000-3200:30-35:300-350:50-55:20-25; The preparation of the second flame retardant comprises the following steps: expansion, inclusion, intercalation, and coating; The expansion method comprises mixing nano-montmorillonite, deionized water and sodium dodecylbenzene sulfonate, stirring at 30-45° C., centrifuging, washing and vacuum drying the precipitate to obtain expanded nano-montmorillonite; During the expansion, the mass ratio of nano-montmorillonite, deionized water, and sodium dodecylbenzene sulfonate is 100-110:1000-1300:3-4; The inclusion method comprises the following steps: mixing methyl octabromoether and acetone, stirring at 15-40° C. to obtain a methyl octabromoether solution; mixing β-cyclodextrin and deionized water, stirring at 15-40° C., dripping the methyl octabromoether solution, stirring after the dripping, standing, evaporating under reduced pressure to remove acetone, filtering, and freeze-drying the filtrate to obtain inclusion cyclodextrin; In the inclusion, the mass ratio of methyl octabromoether, acetone, β-cyclodextrin and deionized water is 4-4.5:28-30:40-45:2800-3000; The intercalation method comprises the following steps: mixing the inclusion cyclodextrin and the first portion of deionized water, stirring at 15-40° C. to obtain the inclusion cyclodextrin dispersion; mixing the expanded nano-montmorillonite and the second portion of deionized water, stirring at 45-55° C., dripping the inclusion cyclodextrin dispersion, stirring after the dripping is completed, dripping the glutaraldehyde aqueous solution, continuing to stir after the dripping is completed, centrifuging, washing, and freeze-drying the precipitate to obtain the intercalated montmorillonite; In the intercalation layer, the mass ratio of the inclusion cyclodextrin, the first portion of deionized water, the expanded nano-montmorillonite, the second portion of deionized water, and the glutaraldehyde aqueous solution is 40-50:4000-5000:90-100:2000-2500:70-80; The coating method comprises mixing intercalated montmorillonite, cyclodextrin and deionized water, stirring at 15-40° C., centrifuging, washing and freeze-drying the precipitate to obtain the second flame retardant; In the coating, the mass ratio of intercalated montmorillonite, cyclodextrin and deionized water is 50-55:100-120:7500-8000; The mixing method comprises adding polystyrene particles, a first flame retardant, a second flame retardant, an antioxidant 1010, and calcium stearate into a high-speed mixer and mixing them at high speed to obtain a mixture; In the mixture, the mass ratio of polystyrene particles, the first flame retardant, the second flame retardant, antioxidant 1010 and calcium stearate is 70-78:20-25:10-15:0.3-0.4:0.3-0.

5.

2. The method for preparing the PS flame retardant masterbatch according to claim 1, It is characterized in that In the prepared mixed solution, the molar concentration of the hydrochloric acid aqueous solution is 0.5 mol / L.

3. The preparation method of PS flame retardant masterbatch according to claim 1, It is characterized in that In the preparation of the cross-linked microspheres, the mass concentration of the glutaraldehyde aqueous solution is 5%; The dropwise addition rate of the mixed solution is 14-15 g / min.

4. The method for preparing the PS flame retardant masterbatch according to claim 1, It is characterized in that In the preparation of the magnesium hydroxide sol, the mass concentration of the magnesium chloride aqueous solution is 20%; The mass concentration of the sodium hydroxide aqueous solution is 8%; The dropping speed of the sodium hydroxide aqueous solution is 6-8 g / min.

5. The method for preparing the PS flame retardant masterbatch according to claim 1, It is characterized in that In the compounding, the dropping speed of the magnesium hydroxide sol is 17-20 g / min.

6. The method for preparing the PS flame retardant masterbatch according to claim 1, It is characterized in that In the silane modification, the mass concentration of the ammonia water is 25%.

7. The method for preparing the PS flame retardant masterbatch according to claim 1, It is characterized in that During the inclusion, the dropping speed of the methyl octabromoether solution is 2-3 g / min; In the intercalation layer, the mass concentration of the glutaraldehyde aqueous solution is 5%; The dropwise addition rate of the cyclodextrin inclusion dispersion is 40-50 g / min; The dropping speed of the glutaraldehyde aqueous solution is 4-5 g / min.

8. The method for preparing the PS flame retardant masterbatch according to claim 1, It is characterized in that The granulation method comprises: adding the mixed material into a twin-screw extruder for granulation to obtain PS flame retardant masterbatch; During the granulation, the screw speed of the twin-screw extruder is 300-350rpm, the temperature of zone 1 is 180-185°C, the temperature of zone 2 is 185-190°C, the temperature of zone 3 is 190-195°C, the temperature of zone 4 is 195-200°C, the temperature of zone 5 is 200-205°C, the temperature of zone 6 is 205-210°C, the temperature of zone 7 is 200-205°C, and the temperature of the die head is 205-210°C.

9. A PS flame retardant masterbatch prepared by the preparation method according to any one of claims 1 to 8.

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