High-flame-retardant toughened regenerated polycarbonate master batch and preparation method thereof

Abstract

The invention discloses a high-flame-retardant toughened regenerated polycarbonate master batch and a preparation method thereof, belongs to the technical field of polycarbonate regeneration, and is used for solving the technical problem that the flame retardant property and mechanical toughness of regenerated polycarbonate need to be further improved in the prior art. The material comprises the following components in parts by weight: 100-110 parts of regenerated polycarbonate, 8-10 parts of a modified flame retardant, 15-19 parts of modified calcium carbonate and 4-7 parts of an auxiliary additive, polycarbonate is subjected to alcoholysis to prepare high-purity bisphenol A, the high-purity bisphenol A is reinforced and modified by using modified polysiloxane, and after the regenerated polycarbonate is prepared, the regenerated polycarbonate is subjected to flame retardant modification by using modified polysiloxane to prepare the regenerated polycarbonate. The modified flame retardant and the modified calcium carbonate are used as reinforcing agent materials, so that the tensile property and the bending strength of the regenerated polycarbonate master batch are effectively improved, and the impact resistance and the flame retardance of the regenerated polycarbonate master batch are also improved.

Description

Technical Field

[0001] The invention relates to the technical field of polycarbonate recycling, and in particular to a highly flame-retardant and toughened recycled polycarbonate masterbatch and a preparation method thereof. Background Art

[0002] Polycarbonate (PC), as a high-performance thermoplastic engineering plastic, has been widely used in many fields such as electronics, automobile manufacturing, construction materials, medical devices, etc. due to its excellent transparency, high impact strength, good heat resistance and excellent processing performance. However, with the increasing attention paid to sustainable development worldwide, the treatment and reuse of waste polycarbonate has become an urgent problem to be solved.

[0003] In recent years, chemical recycling methods have been widely used because they can achieve the depolymerization and reuse of polycarbonate molecules. Among them, alcoholysis, as a mild and efficient chemical recycling method, reacts waste polycarbonate with alcohol compounds to produce high-purity bisphenol A (BPA), providing high-quality raw materials for the preparation of recycled polycarbonate. However, the performance of recycled polycarbonate obtained simply by alcoholysis is often difficult to reach the level of native polycarbonate, especially in terms of flame retardancy and toughness.

[0004] In the prior art, in order to improve the flame retardancy and toughness of recycled polycarbonate, flame retardants such as halogen flame retardants, phosphorus flame retardants, nitrogen flame retardants, etc. are usually introduced into the recycled polycarbonate, which can effectively improve the flame retardancy of polycarbonate. However, due to the difference in material properties, the addition of these flame retardants often has an adverse effect on the mechanical properties of polycarbonate, resulting in a decrease in the toughness of the material. On the other hand, by adding toughening agents, such as rubber toughening agents, thermoplastic elastomers, etc., the toughness of polycarbonate can be significantly improved, but at the same time, its flame retardancy may be reduced, resulting in the flame retardancy and mechanical toughness of recycled polycarbonate need to be further improved.

[0005] In view of the technical defects in this aspect, a solution is now proposed. Summary of the invention

[0006] The object of the present invention is to provide a highly flame retardant and toughened recycled polycarbonate masterbatch and a preparation method thereof, so as to solve the technical problem in the prior art that the flame retardant properties and mechanical toughness of recycled polycarbonate need to be further improved.

[0007] The object of the present invention can be achieved by the following technical scheme: A highly flame-retardant and toughened recycled polycarbonate masterbatch, comprising the following components in parts by weight: 100-110 parts of recycled polycarbonate, 8-10 parts of modified flame retardant, 15-19 parts of modified calcium carbonate and 4-7 parts of auxiliary additives;

[0008] The recycled polycarbonate is obtained by processing the following steps:

[0009] A1, crushing polycarbonate, passing it through a 100-mesh sieve to obtain polycarbonate powder, and performing alcoholysis on the polycarbonate powder to prepare regenerated bisphenol A;

[0010] A2. Add regenerated bisphenol A, diphenyl carbonate, modified polysiloxane and catalyst into a nitrogen-protected reactor and stir. Raise the temperature of the reactor to 200-220° C. and keep the reaction temperature for 3-4 hours. Post-treat to obtain regenerated polycarbonate.

[0011] The synthetic reaction formula of recycled polycarbonate is:

[0012]

[0013] Where:

[0014]

[0015] The synthetic reaction principle of recycled polycarbonate is:

[0016] Under nitrogen protection, the regenerated bisphenol A and the phenolic hydroxyl groups on the modified polysiloxane molecular chain and the ester groups on the diphenyl carbonate are condensed under the catalysis of lithium acetate, and small molecules are removed at the same time, and polysiloxane segments are embedded in the polycarbonate molecular chain segments to prepare regenerated polycarbonate.

[0017] Furthermore, in step A2, the amount ratio of the regenerated bisphenol A, diphenyl carbonate, modified polysiloxane and catalyst is 30g:30g:5-7g:0.02g, the catalyst is lithium acetate, and the post-treatment includes: after the reaction is completed, the temperature of the reactor is lowered to room temperature, dichloromethane is added to the reactor, and stirred until the system is dissolved, n-hexane is added to the reactor, a large amount of solid is precipitated, and filtered, the filter cake is washed twice with n-hexane and then dried, and the filter cake is transferred to a drying oven at a temperature of 60-70°C, and vacuum dried to constant weight to obtain regenerated polycarbonate.

[0018] Furthermore, in step A1, the alcoholysis method is: polycarbonate powder, methanol, activated carbon and catalyst are added to a high-pressure reactor and stirred, the temperature of the high-pressure reactor is increased to 105-115° C., the pressure is increased to 0.2-0.3 MPa, the temperature and pressure are maintained for 4-5 hours, and post-treatment is performed to obtain regenerated bisphenol A.

[0019] The synthetic reaction principle of regenerated bisphenol A is:

[0020] With methanol as the alcoholysis agent, under high temperature and high pressure environment, methanol molecules and sodium hydroxide molecules penetrate into the polycarbonate chain, and the alcohol hydroxyl groups on the methanol molecules attack the carbonate bonds in the polycarbonate chain to form a methoxycarboxylate intermediate. Under the catalyst of sodium hydroxide, the methoxycarboxylate intermediate is further decomposed to generate bisphenol A and sodium methoxide. Sodium methoxide decomposes in the reaction system to generate methanol and sodium hydroxide, so that the continuous progress of the catalytic reaction can reduce the activation energy of the reaction and accelerate the progress of the alcoholysis reaction.

[0021] Furthermore, the amount ratio of the polycarbonate powder, methanol, activated carbon and catalyst is 3g:30-40mL:0.5g:0.8-1.2g, the catalyst is sodium hydroxide, and the post-treatment includes: after the reaction is completed, the temperature of the reactor is lowered to room temperature, suction filtration is performed, the filter cake is washed twice with toluene and then combined with the filtrate and transferred to the reactor, the temperature of the reactor is increased to 85-95°C, the solvent is evaporated under reduced pressure, the temperature of the reactor is lowered to room temperature, toluene is added to the reactor, stirred until the system is dissolved, purified water is added to the reactor, stirred for 10-15min, and the liquid is separated by standing, the organic phase is washed with purified water until neutral, the organic phase is transferred to a reactor with a temperature of 85-95°C, and the solvent is evaporated under reduced pressure to obtain regenerated bisphenol A.

[0022] Further, in step A3, the modified polysiloxane is processed by the following steps:

[0023] B1, octamethylcyclotetrasiloxane, aminopropylmethyldiethoxysilane, 1,1,3,3-tetramethyldisiloxane and a catalyst are added to a reaction kettle and stirred, the temperature of the reaction kettle is increased to 80-90°C, the reaction is kept warm for 5-7h, and post-processed to obtain terminal hydrogen silicone oil;

[0024] The synthetic reaction formula of hydrogen-terminated silicone oil is:

[0025]

[0026] The synthetic reaction principle of hydrogen-terminated silicone oil is:

[0027] Under the catalysis of high temperature and sulfuric acid, the siloxaneoxy groups in aminopropylmethyldiethoxysilane are hydrolyzed into silanol groups, and octamethylcyclotetrasiloxane and 1,1,3,3-tetramethyldisiloxane form silane chains with silanol activity through the cleavage of silicon-oxygen bonds. The hydroxyl groups on the silane chains are recombined to form a double hydrogen-terminated hydrogen-terminated silicone oil containing aminopropyl-modified long polysiloxane chains.

[0028] B2. Add hydrogen-terminated silicone oil, 2-allylphenol and catalyst into a nitrogen-protected reactor and stir. Raise the temperature of the reactor to 85-95° C. and keep the reactor warm for 6-8 hours. Post-treat to obtain modified polysiloxane.

[0029] The synthetic reaction formula of modified polysiloxane is:

[0030]

[0031] The synthetic reaction principle of modified polysiloxane is:

[0032] Under nitrogen protection, the silicon-hydrogen bond in the hydrogen-terminated silicone oil and the carbon-carbon double bond in 2-allylphenol undergo an addition reaction under the action of a platinum catalyst. The hydrogen atom of the silicon-hydrogen bond is added to one carbon atom of the carbon-carbon double bond, while the silicon atom is connected to the other carbon atom to form a carbon-silicon bond. The phenolic hydroxyl groups are modified at both ends of the hydrogen-terminated silicone oil molecular chain to prepare a modified polysiloxane.

[0033] Furthermore, in step B1, the amount ratio of octamethylcyclotetrasiloxane, aminopropylmethyldiethoxysilane, 1,1,3,3-tetramethyldisiloxane and catalyst is 25g:5g:1g:1g, the catalyst is 10-20wt% sulfuric acid, and the post-treatment includes: after the reaction is completed, the temperature of the reactor is reduced to room temperature, purified water is added to the reactor, the polysiloxane product is washed to neutrality and then the water phase is separated, the polysiloxane product is transferred to the reactor, the temperature of the reactor is increased to 90-100°C, and low-boiling impurities are removed under reduced pressure to obtain terminal hydrogen silicone oil; in step B2, the amount ratio of the terminal hydrogen silicone oil, 2-allylphenol and catalyst is 10g:1g:0.1g, the catalyst is a platinum catalyst, and the post-treatment includes: after the reaction is completed, the temperature of the reactor is reduced to room temperature, centrifuged, and an oily modified polysiloxane is obtained.

[0034] Furthermore, in step A3, the preparation method of the modified flame retardant is: adding cyanuric acid, bisphenol A, dichloromethane and triethylamine into a reaction kettle and stirring, adding phenyl dichloride phosphate solution dropwise into the reaction kettle, keeping the temperature for reaction for 6-8 hours, and post-treating to obtain the modified flame retardant.

[0035] The synthetic reaction formula of the modified flame retardant is:

[0036]

[0037] The synthetic reaction principle of modified flame retardant is:

[0038] Under the catalytic action of triethylamine, the chlorine atom of dichlorophenyl phosphate is replaced by the hydroxyl group in cyanuric acid or bisphenol A to form a phosphate ester bond. During the reaction, the ratio of hydroxyl to chlorine atoms is controlled to form a modified flame retardant of hydroxyl-terminated polyphosphate.

[0039] Furthermore, the dosage ratio of cyanuric acid, bisphenol A and phenyl dichloride phosphate is 1 mol:1 mol:2 mol, the dosage ratio of bisphenol A, dichloromethane and triethylamine is 1 g:8 mL:0.5 g, and the phenyl dichloride phosphate solution is composed of phenyl dichloride phosphate and dichloromethane in a dosage ratio of 1 g:3 g. The post-treatment includes: after the reaction is completed, the temperature of the reactor is lowered to room temperature, cyclohexane is added dropwise to the reactor, a large amount of solid is precipitated, and the filter cake is filtered, the filter cake is washed with cyclohexane 3 times and then dried, and the filter cake is transferred to a drying oven at a temperature of 55-65°C, and vacuum dried to constant weight to obtain a modified flame retardant.

[0040] Furthermore, in step A3, the preparation method of modified calcium carbonate is: adding nano calcium carbonate, KH-560, and anhydrous ethanol into a reactor and stirring, raising the temperature of the reactor to 50-60° C., adding alkali solution into the reactor, keeping the reactor warm for 4-5 hours, and post-treating to obtain modified calcium carbonate.

[0041] The synthetic reaction formula of modified calcium carbonate is:

[0042]

[0043] Where: It is nano calcium carbonate particles.

[0044] The synthetic reaction principle of modified calcium carbonate is:

[0045] Under the action of sodium hydroxide solution, the methoxysilane group of KH-560 undergoes a hydrolysis reaction to generate a silanol group. Subsequently, the silanol group undergoes a condensation reaction with the active groups on the surface of calcium carbonate to form a chemical bond, forming a KH-560 coating modification on the outside of the nano-calcium carbonate particles, thereby preparing a modified calcium carbonate with a large number of epoxy groups on the surface.

[0046] Furthermore, the dosage ratio of the nano calcium carbonate, KH-560, anhydrous ethanol and alkali solution is 5g:3g:40mL:8mL, the alkali solution is 0.1-0.3mol / L sodium hydroxide solution, and the post-treatment includes: after the reaction is completed, the reaction temperature is lowered to room temperature, filtered, the filter cake is washed with purified water until it is neutral and then dried, the filter cake is transferred to a drying oven at a temperature of 70-80°C, and vacuum dried to constant weight to obtain modified calcium carbonate.

[0047] The present invention also provides a method for preparing a highly flame retardant and toughened recycled polycarbonate masterbatch. The method for preparing the highly flame retardant and toughened recycled polycarbonate masterbatch comprises: adding recycled polycarbonate, modified flame retardant, modified calcium carbonate and auxiliary additives into a twin-screw extruder, and melt-extruded to obtain the recycled polycarbonate masterbatch.

[0048] Furthermore, the auxiliary additives are composed of a dispersant, a lubricant, a plasticizer, an antioxidant and an antistatic agent in a weight ratio of 3:1:7:2:2, the dispersant is a stearate, the lubricant is one or more of ethylene bisstearamide, polyethylene wax, and microcrystalline wax, the plasticizer is a phthalate, the antioxidant is one or more of antioxidant 1010, antioxidant 168, and antioxidant 246, the antistatic agent is one or more of antistatic agent SN, antistatic agent TM, and antistatic agent SP, the temperatures of the six temperature zones of the twin-screw extruder from the feed end to the discharge end are 265°C, 270°C, 270°C, 275°C, 275°C, and 280°C, respectively, and the spindle speed of the twin-screw extruder is 18r / min.

[0049] The present invention has the following beneficial effects:

[0050] 1. The highly flame-retardant and toughened recycled polycarbonate masterbatch of the present invention is prepared by crushing polycarbonate and then alcoholyzing it to recover recycled bisphenol A, and then using modified polysiloxane as a block reinforcing agent to prepare an active recycled polycarbonate with modified polysiloxane blocks, which is reinforced by the prepared modified flame retardant and modified calcium carbonate to increase the crosslinking degree between molecules and improve the mechanical strength of the recycled polycarbonate masterbatch. In addition, the material molecules cooperate with each other to construct a flame retardant reinforcement system in the recycled polycarbonate masterbatch, thereby improving the flame retardant properties of the recycled polycarbonate masterbatch.

[0051] 2. The highly flame-retardant and toughened recycled polycarbonate masterbatch of the present invention can remove impurities in the polycarbonate powder while decomposing the polycarbonate into bisphenol A by alcoholysis of the polycarbonate powder with a combination of activated carbon and sodium hydroxide, thereby improving the purity of the recycled bisphenol A. By introducing polysiloxane blocks into the molecular chains of the recycled polycarbonate, the polysiloxane is uniformly dispersed in the polycarbonate in the form of blocks. With the polysiloxane as a flexible characteristic chain segment, the toughness of the recycled polycarbonate material can be increased, the fracture strain of the material can be increased, and the bending strength and notched impact strength of the material can be improved. In addition, the silicon-oxygen bond in the molecular structure of the polysiloxane has a higher bond energy, better thermal stability and flame retardancy. After the polysiloxane molecular chain blocks are introduced into the polycarbonate, the flame retardancy of the polycarbonate can be significantly improved.

[0052] 3. The highly flame-retardant and toughened recycled polycarbonate masterbatch of the present invention uses the polyhydroxyl groups on cyanuric acid as reactive groups to construct a modified flame retardant with a polyvalent network crosslinking, and improves its dispersibility in the recycled polycarbonate by modifying calcium carbonate. The presence of nanoparticles can effectively disperse and absorb impact energy, thereby improving the impact toughness of the recycled polycarbonate masterbatch. Under high temperature, the amino or hydroxyl groups of the epoxy groups on the surface of the modified calcium carbonate undergo a ring-opening condensation reaction to form a chemical bond, thereby improving the crosslinking degree between the recycled polycarbonate masterbatch materials, thereby improving the tensile properties and flexural strength of the recycled polycarbonate masterbatch. The hydroxyl groups on the flame retardant molecules can serve as reactive active sites to increase the degree of crosslinking between molecules. The nitrogen and phosphorus rich in the modified flame retardant molecules serve as flame retardant elements, giving them good flame retardant properties, allowing them to cooperate with polysiloxane to improve the flame retardant properties of the material. The inert gases such as carbon dioxide and water vapor produced by the decomposition of calcium carbonate at high temperatures can dilute the concentration of combustible gases and slow down the combustion rate. They cooperate with the modified flame retardant and polysiloxane to construct a flame retardant reinforcement system in the recycled polycarbonate masterbatch, which improves the flame retardant performance level of the recycled polycarbonate masterbatch while improving the tensile properties and bending strength of the material. DETAILED DESCRIPTION

[0053] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] Example 1

[0055] This embodiment provides a method for preparing a highly flame retardant and toughened recycled polycarbonate masterbatch, comprising the following steps:

[0056] S1. Preparation of regenerated bisphenol A by alcoholysis

[0057] The polycarbonate was crushed and passed through a 100-mesh sieve to obtain a polycarbonate powder;

[0058] Weigh: 300g of polycarbonate powder, 3000mL of methanol, 50g of activated carbon and 80g of sodium hydroxide, add them to a high-pressure reactor and stir, the temperature of the high-pressure reactor is increased to 105°C, the pressure is increased to 0.2MPa, and the reaction is maintained at temperature and pressure for 4h. After the reaction is completed, the temperature of the reactor is lowered to room temperature, filtered, the filter cake is washed twice with toluene and then combined with the filtrate and transferred to the reactor, the temperature of the reactor is increased to 85°C, the solvent is evaporated under reduced pressure, the temperature of the reactor is lowered to room temperature, 3L of toluene is added to the reactor, stirred until the system is dissolved, 1L of purified water is added to the reactor, stirred for 10min, and the liquid is separated by standing, the organic phase is washed with purified water until neutral, the organic phase is transferred to a reactor with a temperature of 85°C, and the solvent is evaporated under reduced pressure to obtain regenerated bisphenol A.

[0059] S2. Preparation of modified polysiloxane

[0060] Weigh: 250g of octamethylcyclotetrasiloxane, 50g of aminopropylmethyldiethoxysilane, 10g of 1,1,3,3-tetramethyldisiloxane and 10g of 10-20wt% sulfuric acid, add them into a reactor and stir, raise the temperature of the reactor to 80°C, and keep the reaction for 5h. After the reaction is completed, lower the temperature of the reactor to room temperature, add 500mL of purified water into the reactor, wash the polysiloxane product to neutrality, separate the water phase, transfer the polysiloxane product to the reactor, raise the temperature of the reactor to 90°C, and remove low-boiling impurities under reduced pressure to obtain terminal hydrogen silicone oil;

[0061] Weigh: 500 g of terminal hydrogen silicone oil, 50 g of 2-allylphenol and 5 g of platinum carbon catalyst, add them into a nitrogen-protected reactor and stir, raise the temperature of the reactor to 85°C, and keep the reactor warm for 6 hours. After the reaction is completed, lower the temperature of the reactor to room temperature, centrifuge, and obtain oily modified polysiloxane.

[0062] S3. Preparation of recycled polycarbonate

[0063] Weigh: 300g of regenerated bisphenol A, 300g of diphenyl carbonate, 50g of modified polysiloxane and 0.2g of lithium acetate, add them to a nitrogen-protected reactor and stir, raise the temperature of the reactor to 200°C, and keep the reaction warm for 3h. After the reaction is completed, lower the temperature of the reactor to room temperature, add 5L of dichloromethane to the reactor, stir until the system is dissolved, add 10L of n-hexane to the reactor, a large amount of solid precipitates, filter, wash the filter cake twice with n-hexane and then dry it, transfer the filter cake to a drying oven at 60°C, and vacuum dry it to constant weight to obtain regenerated polycarbonate.

[0064] S4. Preparation of modified flame retardant

[0065] Mix phenyl dichloride phosphate and dichloromethane in a ratio of 1g:3g to obtain a phenyl dichloride phosphate solution;

[0066] Weigh: 129.1 g of cyanuric acid, 228.3 g of bisphenol A, 1826 mL of dichloromethane and 114.1 g of triethylamine, add them into a reactor and stir, add 844 g of phenyl dichlorophosphate solution dropwise into the reactor, and keep warm for 6 hours. After the reaction is completed, the temperature of the reactor is lowered to room temperature, 4 L of cyclohexane is added dropwise into the reactor, a large amount of solid precipitates, and it is filtered off. The filter cake is washed 3 times with cyclohexane and then dried. The filter cake is transferred to a drying oven at a temperature of 55°C and vacuum dried to constant weight to obtain a modified flame retardant.

[0067] S5. Preparation of modified calcium carbonate

[0068] Weigh: 200g of nano calcium carbonate, 120g of KH-560, and 1600mL of anhydrous ethanol, add them into a reactor and stir, raise the temperature of the reactor to 50°C, add 240mL of 0.1mol / L sodium hydroxide solution into the reactor, and keep the reactor warm for 4h. After the reaction is completed, the reaction temperature is lowered to room temperature, filtered, and the filter cake is washed with purified water until it is neutral and then dried. The filter cake is transferred to a drying oven at a temperature of 70°C and vacuum dried to constant weight to obtain modified calcium carbonate.

[0069] S6. Preparation of recycled polycarbonate masterbatch

[0070] Calcium stearate, ethylene bisstearamide, dimethyl phthalate, antioxidant 1010 and antistatic agent SN are uniformly mixed in a weight ratio of 3:1:7:2:2 to obtain an auxiliary additive;

[0071] Weigh by weight: 100 parts of recycled polycarbonate, 8 parts of modified flame retardant, 15 parts of modified calcium carbonate and 4 parts of auxiliary additives are added to a twin-screw extruder. The temperatures of the six temperature sections from the feed end to the discharge end of the twin-screw extruder are 265°C, 270°C, 270°C, 275°C, 275°C, and 280°C, respectively. The main shaft speed of the twin-screw extruder is 18r / min. The materials are melt-extruded and pelletized through the twin-screw extruder to obtain recycled polycarbonate masterbatch.

[0072] Example 2

[0073] This embodiment provides a method for preparing a highly flame retardant and toughened recycled polycarbonate masterbatch, comprising the following steps:

[0074] S1. Preparation of regenerated bisphenol A by alcoholysis

[0075] The polycarbonate was crushed and passed through a 100-mesh sieve to obtain a polycarbonate powder;

[0076] Weigh: 300g of polycarbonate powder, 3500mL of methanol, 50g of activated carbon and 100g of sodium hydroxide, add them to a high-pressure reactor and stir, the temperature of the high-pressure reactor is increased to 110°C, the pressure is increased to 0.25MPa, and the reaction is maintained at temperature and pressure for 4.5h. After the reaction is completed, the temperature of the reactor is lowered to room temperature, filtered, the filter cake is washed twice with toluene and then combined with the filtrate and transferred to the reactor, the temperature of the reactor is increased to 90°C, the solvent is evaporated under reduced pressure, the temperature of the reactor is lowered to room temperature, 3L of toluene is added to the reactor, stirred until the system is dissolved, 1L of purified water is added to the reactor, stirred for 13min, and the liquid is separated by standing, the organic phase is washed with purified water until neutral, the organic phase is transferred to a reactor at a temperature of 90°C, and the solvent is evaporated under reduced pressure to obtain regenerated bisphenol A.

[0077] S2. Preparation of modified polysiloxane

[0078] Weigh: 250g of octamethylcyclotetrasiloxane, 50g of aminopropylmethyldiethoxysilane, 10g of 1,1,3,3-tetramethyldisiloxane and 10g of 15wt% sulfuric acid, add them into a reactor and stir, raise the temperature of the reactor to 85°C, and keep the reaction for 6h. After the reaction is completed, lower the temperature of the reactor to room temperature, add 500mL of purified water into the reactor, wash the polysiloxane product to neutrality, separate the water phase, transfer the polysiloxane product to the reactor, raise the temperature of the reactor to 95°C, and remove low-boiling impurities under reduced pressure to obtain terminal hydrogen silicone oil;

[0079] Weigh: 500 g of terminal hydrogen silicone oil, 50 g of 2-allyl phenol and 5 g of platinum carbon catalyst, add them into a nitrogen-protected reactor and stir, raise the temperature of the reactor to 90° C., and keep the reactor warm for 7 hours. After the reaction is completed, lower the temperature of the reactor to room temperature, centrifuge, and obtain oily modified polysiloxane.

[0080] S3. Preparation of recycled polycarbonate

[0081] Weigh: 300g of regenerated bisphenol A, 300g of diphenyl carbonate, 60g of modified polysiloxane and 0.2g of lithium acetate, add them to a nitrogen-protected reactor and stir, the temperature of the reactor is raised to 210°C, and the reaction is kept warm for 3.5h. After the reaction is completed, the temperature of the reactor is lowered to room temperature, 5L of dichloromethane is added to the reactor, and the system is stirred until it is dissolved. 10L of n-hexane is added to the reactor, a large amount of solid is precipitated, and it is filtered. The filter cake is washed twice with n-hexane and then dried. The filter cake is transferred to a drying oven at a temperature of 65°C and vacuum dried to constant weight to obtain regenerated polycarbonate.

[0082] S4. Preparation of modified flame retardant

[0083] The dichlorophenyl phosphate and dichloromethane were mixed uniformly in a dosage ratio of 1g:3g to obtain a dichlorophenyl phosphate solution;

[0084] Weigh: 129.1 g of cyanuric acid, 228.3 g of bisphenol A, 1826 mL of dichloromethane and 114.1 g of triethylamine, add them into a reactor and stir, add 844 g of phenyl dichlorophosphate solution dropwise into the reactor, and keep warm for 7 hours. After the reaction is completed, the temperature of the reactor is lowered to room temperature, 4 L of cyclohexane is added dropwise into the reactor, a large amount of solid precipitates, and it is filtered off. The filter cake is washed 3 times with cyclohexane and then dried. The filter cake is transferred to a drying oven at a temperature of 60°C and vacuum dried to constant weight to obtain a modified flame retardant.

[0085] S5. Preparation of modified calcium carbonate

[0086] Weigh: 200g of nano calcium carbonate, 120g of KH-560, and 1600mL of anhydrous ethanol, add them into a reactor and stir, raise the temperature of the reactor to 55°C, add 240mL of 0.2mol / L sodium hydroxide solution into the reactor, and keep the reactor warm for 4.5h. After the reaction is completed, the reaction temperature is lowered to room temperature, filtered, and the filter cake is washed with purified water until it is neutral and then dried. The filter cake is transferred to a drying oven at a temperature of 75°C and vacuum dried to constant weight to obtain modified calcium carbonate.

[0087] S6. Preparation of recycled polycarbonate masterbatch

[0088] Mix zinc stearate, polyethylene wax, diethyl phthalate, antioxidant 168 and antistatic agent TM in a weight ratio of 3:1:7:2:2 to obtain an auxiliary additive;

[0089] Weigh by weight: 105 parts of recycled polycarbonate, 9 parts of modified flame retardant, 17 parts of modified calcium carbonate and 6 parts of auxiliary additives are added to a twin-screw extruder. The temperatures of the six temperature sections from the feed end to the discharge end of the twin-screw extruder are 265°C, 270°C, 270°C, 275°C, 275°C, and 280°C, respectively. The main shaft speed of the twin-screw extruder is 18r / min. The materials are melt-extruded and pelletized through the twin-screw extruder to obtain recycled polycarbonate masterbatch.

[0090] Example 3

[0091] This embodiment provides a method for preparing a highly flame retardant and toughened recycled polycarbonate masterbatch, comprising the following steps:

[0092] S1. Preparation of regenerated bisphenol A by alcoholysis

[0093] The polycarbonate was crushed and passed through a 100-mesh sieve to obtain a polycarbonate powder;

[0094] Weigh: 300g of polycarbonate powder, 4000mL of methanol, 50g of activated carbon and 120g of sodium hydroxide, add them to a high-pressure reactor and stir, the temperature of the high-pressure reactor is increased to 115°C, the pressure is increased to 0.3MPa, and the reaction is maintained at temperature and pressure for 5h. After the reaction is completed, the temperature of the reactor is lowered to room temperature, filtered, the filter cake is washed twice with toluene and then combined with the filtrate and transferred to the reactor, the temperature of the reactor is increased to 95°C, the solvent is evaporated under reduced pressure, the temperature of the reactor is lowered to room temperature, 3L of toluene is added to the reactor, stirred until the system is dissolved, 1L of purified water is added to the reactor, stirred for 15min, and the liquid is separated by standing, the organic phase is washed with purified water until neutral, the organic phase is transferred to a reactor at a temperature of 95°C, and the solvent is evaporated under reduced pressure to obtain regenerated bisphenol A.

[0095] S2. Preparation of modified polysiloxane

[0096] Weigh: 250g of octamethylcyclotetrasiloxane, 50g of aminopropylmethyldiethoxysilane, 10g of 1,1,3,3-tetramethyldisiloxane and 10g of 20wt% sulfuric acid, add them into a reactor and stir, raise the temperature of the reactor to 90°C, keep the reaction for 7h, after the reaction is completed, lower the temperature of the reactor to room temperature, add 500mL of purified water into the reactor, wash the polysiloxane product to neutrality, separate the water phase, transfer the polysiloxane product to the reactor, raise the temperature of the reactor to 100°C, remove low-boiling impurities under reduced pressure, and obtain terminal hydrogen silicone oil;

[0097] Weigh: 500 g of terminal hydrogen silicone oil, 50 g of 2-allyl phenol and 5 g of platinum carbon catalyst, add them into a nitrogen-protected reactor and stir, raise the temperature of the reactor to 95°C, and keep the reactor warm for 8 hours. After the reaction is completed, lower the temperature of the reactor to room temperature, centrifuge, and obtain oily modified polysiloxane.

[0098] S3. Preparation of recycled polycarbonate

[0099] Weigh: 300g of regenerated bisphenol A, 300g of diphenyl carbonate, 70g of modified polysiloxane and 0.2g of lithium acetate, add them to a nitrogen-protected reactor and stir, raise the temperature of the reactor to 220°C, and keep the reaction for 4 hours. After the reaction is completed, lower the temperature of the reactor to room temperature, add 5L of dichloromethane to the reactor, stir until the system is dissolved, add 10L of n-hexane to the reactor, a large amount of solid precipitates, filter, wash the filter cake twice with n-hexane and then dry it, transfer the filter cake to a drying oven at a temperature of 70°C, and vacuum dry it to constant weight to obtain regenerated polycarbonate.

[0100] S4. Preparation of modified flame retardant

[0101] The dichlorophenyl phosphate and dichloromethane were mixed uniformly in a dosage ratio of 1g:3g to obtain a dichlorophenyl phosphate solution;

[0102] Weigh: 129.1 g of cyanuric acid, 228.3 g of bisphenol A, 1826 mL of dichloromethane and 114.1 g of triethylamine, add them into a reactor and stir, add 844 g of phenyl dichlorophosphate solution dropwise into the reactor, and keep warm for 8 hours. After the reaction is completed, the temperature of the reactor is lowered to room temperature, 4 L of cyclohexane is added dropwise into the reactor, a large amount of solid precipitates, and it is filtered off. The filter cake is washed 3 times with cyclohexane and then dried. The filter cake is transferred to a drying oven at a temperature of 65°C and vacuum dried to constant weight to obtain a modified flame retardant.

[0103] S5. Preparation of modified calcium carbonate

[0104] Weigh: 200g of nano calcium carbonate, 120g of KH-560, and 1600mL of anhydrous ethanol, add them into a reactor and stir, raise the temperature of the reactor to 60°C, add 240mL of 0.3mol / L sodium hydroxide solution into the reactor, and keep the reactor warm for 5h. After the reaction is completed, the reaction temperature is lowered to room temperature, filtered, and the filter cake is washed with purified water until it is neutral and then dried. The filter cake is transferred to a drying oven at a temperature of 80°C and vacuum dried to constant weight to obtain modified calcium carbonate.

[0105] S6. Preparation of recycled polycarbonate masterbatch

[0106] Mixing sodium stearate, microcrystalline wax, diisobutyl phthalate, antioxidant 246 and antistatic agent SP in a weight ratio of 3:1:7:2:2 to obtain an auxiliary additive;

[0107] Weigh by weight: 110 parts of recycled polycarbonate, 10 parts of modified flame retardant, 19 parts of modified calcium carbonate and 7 parts of auxiliary additives are added to a twin-screw extruder. The temperatures of the six temperature sections from the feed end to the discharge end of the twin-screw extruder are 265°C, 270°C, 270°C, 275°C, 275°C, and 280°C, respectively. The main shaft speed of the twin-screw extruder is 18r / min. The products are melt-extruded and pelletized through the twin-screw extruder to obtain recycled polycarbonate masterbatch.

[0108] Comparative Example 1

[0109] The difference between this comparative example and Example 3 is that the modified polysiloxane in step S3 is replaced by the hydrogen-terminated silicone oil in step S2.

[0110] Comparative Example 2

[0111] The difference between this comparative example and Example 3 is that in step S4, the usage ratio of cyanuric acid, bisphenol A and phenyl dichloride phosphate is 1 mol:1 mol:2.6 mol.

[0112] Comparative Example 3

[0113] The difference between this comparative example and Example 3 is that step S5 is eliminated and modified calcium carbonate is not added in step S6.

[0114] Comparative Example 4

[0115] The difference between this comparative example and Example 3 is that the polycarbonate powder in step S1 is used to replace the recycled polycarbonate in step S6.

[0116] Performance Testing:

[0117] The tensile strength, tensile fracture nominal strain, flexural strength and Izod notched impact strength of the recycled polycarbonate masterbatch prepared in Examples 1-3 and Comparative Examples 1-4 were tested with reference to the standard GB / T 40006.7-2021 "Plastics Recycled Plastics Part 7: Polycarbonate (PC) Materials";

[0118] The vertical combustion performance of the recycled polycarbonate masterbatch prepared in Examples 1-3 and Comparative Examples 1-4 was tested with reference to the standard GB / T 2408-2021 “Horizontal and vertical methods for determination of combustion performance of plastics”;

[0119] The specific test results are shown in Table 1 below.

[0120] Table 1-Performance test data of samples

[0121]

[0122] Data Analysis:

[0123] Comparing and analyzing the data in Table 1 above, the recycled polycarbonate masterbatch prepared by the present invention has a tensile strength of 76.8 MPa, a tensile fracture nominal strain of 87.2%, a flexural strength of 110.3 MPa, and an Izod notched impact strength of 67.6 kJ / m 2 , the vertical combustion performance reaches V-0 level, and all performance parameters are better than the control example, which means that the present invention is to prepare high-purity bisphenol A by alcoholysis of polycarbonate, and then use modified polysiloxane to enhance and modify it. After preparing recycled polycarbonate, modified flame retardant and modified calcium carbonate are used as reinforcing agent materials, which not only effectively improves the tensile properties and flexural strength of the recycled polycarbonate masterbatch, but also improves the impact resistance and flame retardancy of the recycled polycarbonate masterbatch.

[0124] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

[0125] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0126] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A highly flame retardant and toughened recycled polycarbonate masterbatch, characterized in that: The invention comprises the following components in parts by weight: 100-110 parts of recycled polycarbonate, 8-10 parts of modified flame retardant, 15-19 parts of modified calcium carbonate and 4-7 parts of auxiliary additives; The recycled polycarbonate is obtained by processing the following steps: A1, crushing polycarbonate, passing it through a 100-mesh sieve to obtain polycarbonate powder, and alcoholyzing the polycarbonate powder to prepare regenerated bisphenol A; A2. Add regenerated bisphenol A, diphenyl carbonate, modified polysiloxane and catalyst into a nitrogen-protected reactor and stir. Raise the temperature of the reactor to 200-220° C. and keep the reaction temperature for 3-4 hours. Post-treat to obtain regenerated polycarbonate.

2. The highly flame retardant and toughened recycled polycarbonate masterbatch according to claim 1, characterized in that: In step A2, the amount ratio of the regenerated bisphenol A, diphenyl carbonate, modified polysiloxane and catalyst is 30g:30g:5-7g:0.02g, and the catalyst is lithium acetate.

3. The highly flame retardant and toughened recycled polycarbonate masterbatch according to claim 1, characterized in that: In step A3, the modified polysiloxane is processed by the following steps: B1, octamethylcyclotetrasiloxane, aminopropylmethyldiethoxysilane, 1,1,3,3-tetramethyldisiloxane and a catalyst are added to a reaction kettle and stirred, the temperature of the reaction kettle is increased to 80-90°C, the reaction is kept warm for 5-7h, and post-processed to obtain terminal hydrogen silicone oil; B2. Add hydrogen-terminated silicone oil, 2-allylphenol and catalyst into a nitrogen-protected reactor and stir. Raise the temperature of the reactor to 85-95° C. and keep the reactor warm for 6-8 hours. Post-treat to obtain modified polysiloxane.

4. The highly flame retardant and toughened recycled polycarbonate masterbatch according to claim 3, characterized in that: In step B1, the amount ratio of octamethylcyclotetrasiloxane, aminopropylmethyldiethoxysilane, 1,1,3,3-tetramethyldisiloxane and the catalyst is 25g:5g:1g:1g, and the catalyst is 10-20wt% sulfuric acid; in step B2, the amount ratio of the terminal hydrogen silicone oil, 2-allylphenol and the catalyst is 10g:1g:0.1g, and the catalyst is a platinum catalyst.

5. The highly flame retardant and toughened recycled polycarbonate masterbatch according to claim 1, characterized in that: In step A3, the preparation method of the modified flame retardant is: adding cyanuric acid, bisphenol A, dichloromethane and triethylamine into a reaction kettle and stirring, adding phenyl dichloride phosphate solution dropwise into the reaction kettle, keeping the temperature for reaction for 6-8 hours, and post-treating to obtain the modified flame retardant.

6. The highly flame retardant and toughened recycled polycarbonate masterbatch according to claim 5, characterized in that: The dosage ratio of cyanuric acid, bisphenol A and phenyl dichloride phosphate is 1 mol:1 mol:2 mol, the dosage ratio of bisphenol A, dichloromethane and triethylamine is 1 g:8 mL:0.5 g, and the phenyl dichloride phosphate solution is composed of phenyl dichloride phosphate and dichloromethane in a dosage ratio of 1 g:3 g.

7. The highly flame retardant and toughened recycled polycarbonate masterbatch according to claim 1, characterized in that: In step A3, the preparation method of modified calcium carbonate is: adding nano calcium carbonate, KH-560 and anhydrous ethanol into a reactor and stirring, raising the temperature of the reactor to 50-60° C., adding alkali solution into the reactor, keeping the reactor warm for 4-5 hours, and post-treating to obtain modified calcium carbonate.

8. The highly flame retardant and toughened recycled polycarbonate masterbatch according to claim 7, characterized in that: The dosage ratio of the nano calcium carbonate, KH-560, anhydrous ethanol and alkali solution is 5g:3g:40mL:8mL, and the alkali solution is 0.1-0.3mol / L sodium hydroxide solution.

9. The method for preparing a highly flame retardant and toughened recycled polycarbonate masterbatch according to any one of claims 1 to 8, characterized in that: The preparation method of the highly flame-retardant and toughened recycled polycarbonate masterbatch is as follows: recycled polycarbonate, modified flame retardant, modified calcium carbonate and auxiliary additives are added into a twin-screw extruder, and melt-extruded to obtain recycled polycarbonate masterbatch.

10. The method for preparing a highly flame-retardant and toughened recycled polycarbonate masterbatch according to claim 9, characterized in that: The auxiliary additives are composed of a dispersant, a lubricant, a plasticizer, an antioxidant and an antistatic agent in a weight ratio of 3:1:7:2:2, the dispersant is stearate, the lubricant is one or more of ethylene bisstearamide, polyethylene wax, and microcrystalline wax, the plasticizer is phthalate, the antioxidant is one or more of antioxidant 1010, antioxidant 168, and antioxidant 246, the antistatic agent is one or more of antistatic agent SN, antistatic agent TM, and antistatic agent SP, the temperatures of the six temperature sections of the twin-screw extruder from the feed end to the discharge end are 265°C, 270°C, 270°C, 275°C, 275°C, and 280°C, respectively, and the spindle speed of the twin-screw extruder is 18r / min.

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