CN114196002A

CN114196002A - Preparation method of transparent flame-retardant novel polycarbonate, polycarbonate and application thereof

Info

Publication number: CN114196002A
Application number: CN202210027120.5A
Authority: CN
Inventors: 高卫强; 陈连清; 祁先勇; 张振威; 张雷
Original assignee: Wanhua Chemical Ningbo Co Ltd
Current assignee: Wanhua Chemical Ningbo Co Ltd
Priority date: 2022-01-11
Filing date: 2022-01-11
Publication date: 2022-03-18
Anticipated expiration: 2042-01-11
Also published as: CN114196002B

Abstract

The invention discloses a preparation method of a novel transparent flame-retardant polycarbonate, the polycarbonate and application thereof, and the preparation method comprises the following steps: A) carrying out photochemical reaction on a water phase formed by dissolving bisphenol A and triphenol in an alkali liquor and an oil phase formed by dissolving phosgene in carbon tetrachloride to prepare a polycarbonate oligomer with hindered phenolic hydroxyl active groups, and then adding a catalyst and an end capping agent to react to obtain a high molecular weight linear polycarbonate solution; B) phosphorus oxychloride and bisphenol A react under the action of a catalyst to produce an intermediate with a phosphate acyl chloride end group; C) putting the products of the step A) and the step B) into a reaction kettle to react under certain conditions to generate novel polycarbonate with a flame retardant short side branched chain structure. The novel polycarbonate disclosed by the invention can realize the characteristics of transparency, high flame retardance, high fluidity, low internal stress and the like, has better heat resistance and impact property, and has an intrinsic advantage in applications such as electronic and electric transparent windows.

Description

Preparation method of transparent flame-retardant novel polycarbonate, polycarbonate and application thereof

Technical Field

The invention relates to the technical field of polycarbonate, in particular to a preparation method of flame retardant grafted polycarbonate side group polymerized novel transparent flame retardant polycarbonate, polycarbonate and application thereof.

Background

Polycarbonate (PC) has outstanding impact resistance, heat resistance, high light transmittance and other properties, is the second largest engineering plastic which is second to nylon in the world, has wide application in national economy, and has entered into a plurality of fields such as automobiles, electronics and electrics, buildings, office equipment, packaging, sports equipment, medical care, household goods and the like. However, with the progress of society and the development of industries, for example, the trend of thinning electronic and electric appliances provides higher requirements for the flame retardance and the fluidity of polycarbonate materials, and in addition, transparent parts such as charging pile windows and the like require polycarbonate to keep the flame retardance and high transparency, and meanwhile, the internal stress cannot be too large, so that the phenomenon of rainbow patterns is prevented from affecting the perspective effect. The conventional polycarbonate has relatively poor flame retardant property and cannot meet the minimum flame retardant requirement of various industries, so that the common technical means is to perform flame retardant modification on the polycarbonate, but most of the modification means bring about the defects while improving the flame retardant property, and cannot meet the final requirement.

For example, patent publication No. CN 101353473A discloses a method for improving flame retardance by adding brominated polycarbonate oligomer as a flame retardant to polycarbonate, wherein the flame retardance can achieve a film grade of 0.25mmV-0, but a large amount of toxic and harmful substances are generated during combustion of a brominated flame retardant and are limited by most countries, so that the method does not conform to the future social development trend and cannot become an effective solution. Patent CN 102844377B discloses a method for improving flame retardant property by adding sulfonate flame retardant into polycarbonate, which can realize flame retardant grade of 2.0mmV0 and fog degree below 2% at 3 mm; the method is the most commonly used method in the industry at present, but the sulfonate flame retardant cannot realize the flame retardant performance in the aspect of thin walls, the problem that V0 cannot be broken through at the present stage under the thickness of 0.8mm, 1.0mm, even 1.5mm and the like is solved, and meanwhile, after the fluidity of polycarbonate is improved, the flame retardant effect of sulfonate is further reduced, and even the grade of 3.0mmV0 cannot be realized.

Patent CN110358276A discloses a method of adding an ionic liquid flame retardant to improve the flame retardant performance of polycarbonate, but in practical situations, the ionic liquid has low flame retardant efficiency and cannot obtain excellent flame retardant effect, so that no mainstream flame retardant solution is formed.

Patent CN 109265950a discloses a method for preparing transparent polycarbonate material suitable for two-color injection molding by adding liquid phosphorus flame retardant and powder flame retardant, but the toughness of the material is greatly affected when only adding phosphorus flame retardant or powder flame retardant selected from hydroxide, so that the polycarbonate loses the advantage of high toughness.

Patent CN112538252A discloses that the phosphorus flame retardant and the silicon flame retardant are compounded and applied to siloxane copolymerized polycarbonate and arylation block copolymerized polycarbonate, the product can realize higher flame retardant and flame retardant performances, but the base material of the invention is not a conventional product and cannot meet large-scale popularization and low-price popularization in the aspects of market supply and product price.

Finally, most foreign copolymerization patents (such as Saebick, Bright, etc.) focus on the preparation of silicon-based polycarbonates by block copolymerization of silicon, and the copolymers themselves have various advantages of low temperature resistance, flame retardancy, solvent resistance, etc., but the flame retardancy also needs to be further improved.

In summary, transparent flame retardant polycarbonate meets the increasing market demand at present, but the prior art means all have the difficulties of respective technical bottlenecks.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a preparation method of a polycarbonate material with high fluidity, low internal stress, transparency and flame retardance. According to the invention, the polycarbonate with hindered phenol active groups is formed by copolymerizing a ternary phenol component, two phenolic hydroxyl groups in the ternary phenol normally react in the reaction process to form linear polycarbonate, and the other phenolic hydroxyl group can not participate in the reaction under the same condition because of the larger steric hindrance effect generated by the existence of a neighboring group, so that the polycarbonate can exist as an active group; the intermediate with the phosphoric acid double-chlorine end group in the formula I is selected to react with the hindered phenolic hydroxyl group at high temperature, so that the conventional linear polycarbonate molecular formula has the phosphorus flame-retardant short side group, and a high-fluidity low-internal-stress product can be obtained, and meanwhile, a high flame-retardant effect can be realized.

The invention also aims to provide the transparent flame-retardant novel polycarbonate prepared by the preparation method.

It is a further object of the present invention to provide the use of such novel transparent flame retardant polycarbonates.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of a novel transparent flame-retardant polycarbonate comprises the following steps:

a) carrying out photochemical reaction on a water phase formed by dissolving bisphenol A and triphenol in an alkali liquor and an oil phase formed by dissolving phosgene in carbon tetrachloride to prepare a polycarbonate oligomer with hindered phenolic hydroxyl active groups, and then adding a catalyst and an end capping agent to react to obtain a high molecular weight linear polycarbonate solution;

b) reacting phosphorus oxychloride and bisphenol A under the action of a catalyst at a certain temperature to generate an intermediate of a formula I, wherein n is 1 and 2, and refluxing excessive phosphorus oxychloride until no hydrogen chloride is generated to obtain a purified intermediate of the formula I;

c) putting the intermediate of the formula I in the step b) into a reaction kettle containing the high molecular weight linear polycarbonate solution in the step a), carrying out interfacial polymerization reaction under the action of an inert atmosphere, high temperature and high pressure and a catalyst, adding an end capping agent after a certain time, stopping the reaction after no hydrogen chloride is generated, cooling, reducing pressure and removing the solvent to obtain the novel transparent flame-retardant polycarbonate.

In a specific embodiment, the structural formula of the triphenol in the step a) is shown as formula II:

wherein R is₁、R₂Each independently selected from alkyl with carbon atom number of 2-18 or one or combination of benzene ring and naphthalene ring, preferably methyl or ethyl; r₃Selected from hydrocarbon groups having 2 to 18 carbon atoms or branched structural groups thereof, preferablyIs methyl.

In a specific embodiment, the mass concentration of the phenolate in the phenolate aqueous phase in the step a) is 10-15%, and the ratio of the trisphenol in the total mass of the phenolate is 0.1-5%; preferably, the lye is an aqueous solution of an alkali metal hydroxide, more preferably an aqueous sodium hydroxide solution; the pH value of the phenolate aqueous phase is controlled to 11-11.8.

In a specific embodiment, the residence time of the reaction in step a) is 5 to 50min, preferably 5 to 40min, and more preferably 5 to 25min, and the total molar amount of phosgene in step a) is 1.00 to 1.16 times, preferably 1.02 to 1.10 times the sum of the molar amounts of triphenol and bisphenol A.

In a particular embodiment, the molar ratio of bisphenol a to phosphorus oxychloride in step b) is 1: 2.5, the catalyst is selected from any one or combination of calcium chloride and magnesium chloride, preferably calcium chloride, the addition amount of the catalyst is 0.1-0.4%, preferably 0.15-0.3% of the mass of the bisphenol A, and the reaction temperature in the step b) is 100-120 ℃; the reaction residence time is 3.5-6 h.

In a specific embodiment, the inert atmosphere in step c) is a nitrogen atmosphere, and the reaction temperature in the reaction kettle is 130-170 ℃, preferably 145-155 ℃; the reaction residence time is 4 to 6 hours, preferably 4.5 to 5.5 hours; the reaction pressure is 5 to 15atm, preferably 7 to 12atm, and more preferably 8 to 10 atm.

In a specific embodiment, the catalyst in the step c) is selected from any one or a combination of calcium chloride and magnesium chloride, preferably calcium chloride, and the addition amount of the catalyst is 0.3-0.6% of the mass of the triphenol monomer in the step a); preferably 0.4-0.55%; the end-capping agent is selected from phenol or p-tert-butylphenol, preferably phenol.

In a particular embodiment, the intermediate of formula i and the blocking agent are added in step c) in an amount such that the ratio of moles of intermediate of formula i, moles of triphenol and moles of blocking agent, based on moles of triphenol in the phenoxide of step a), is from 1.01 to 1.30: 1: 4.04-5.20.

On the other hand, the novel transparent flame-retardant polycarbonate is prepared by the preparation method; preferably, the novel polycarbonate can realize the flame retardant grade of 0.8-3.0mmV0/V1/V2, the melt index is 7-60g/10min, the light transmittance is more than 87%, and the impact property reaches 500-900J/m.

In a further aspect, the transparent flame-retardant polycarbonate is used in transparent windows, preferably in transparent windows in the field of electronics and electrical.

Compared with the prior art, the invention has the advantages that:

by adopting the triphenol component with the structure of formula II to participate in the interfacial polymerization reaction of polycarbonate, hindered phenolic hydroxyl with activity is introduced into a polycarbonate molecular chain; phosphorus oxychloride and bisphenol A react under specific conditions to generate an intermediate I with a phosphate chloride group at the end group; and finally, reacting the intermediate I with phenolic hydroxyl with certain activity in the polycarbonate to produce the novel polycarbonate polymer with the flame retardant side chain. The polymer has phosphorus flame-retardant groups, so that the molecular level dispersion of the flame-retardant groups is realized, the flame-retardant property is greatly improved, and different flame-retardant grades of V0-V2 with the thickness of 0.8-3.0mm can be realized according to the content difference; meanwhile, the existence of short side chains leads to the increase of molecular distance, the material flowability becomes good, and the internal stress is greatly reduced after molding; and because the short side groups are very similar to the main chain result, the introduction of the side groups has no influence on the transparency of the material and keeps the same transparency as the conventional product.

The specific implementation mode is as follows:

the following examples will further illustrate the method provided by the present invention in order to better understand the technical solution of the present invention, but the present invention is not limited to the listed examples, and should also include any other known modifications within the scope of the claims of the present invention.

a) dissolving bisphenol A and triphenol in an aqueous solution of alkali metal hydroxide to form a phenolate aqueous phase, and dissolving phosgene in carbon tetrachloride according to a concentration of 7% to form an oil phase; carrying out photochemical reaction on the water phase and the oil phase to prepare a polycarbonate oligomer with hindered phenolic hydroxyl active groups; then adding a catalyst and an end-capping reagent to react to obtain a high molecular weight polycarbonate solution.

b) Under the action of a catalyst, raising the temperature of phosphorus oxychloride and bisphenol A to a certain temperature to react to generate an intermediate I (namely the intermediate of the formula I) until no hydrogen chloride is generated, and refluxing excessive phosphorus oxychloride; where n is 1 and 2, the reaction typically produces an intermediate i which is a mixture comprising n1 and n 2.

c) Putting the intermediate generated in the step b) into an autoclave containing the high molecular weight linear polycarbonate carbon tetrachloride solution with the hindered phenolic hydroxyl active group generated in the step a), raising the temperature to a certain temperature in a nitrogen atmosphere, carrying out interfacial polymerization reaction under the action of a catalyst, adding phenol for termination after a certain time, stopping after no hydrogen chloride is generated, cooling and reducing the pressure, and then carrying out devolatilization to obtain the transparent flame-retardant polycarbonate.

In the step a), the general structural formula of the triphenol is shown as formula II:

wherein R is₁、R₂One or a combination of hydrocarbon groups with 2-18 carbon atoms or high molecular weight groups such as benzene ring, naphthalene ring and the like, such as long-chain alkyl groups of ethyl, propyl, butyl, pentyl, hexyl, heptyl, octane, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl and octadecyl or branched structures thereof, or benzene ring and naphthalene ring, preferably methyl or ethyl; r₃Selected from hydrocarbon radicals having a number of carbon atoms of from 2 to 18, such as ethyl, propyl, butyl, pentyl, hexyl, heptyl, octane, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, decyl, or mixtures thereof,The long-chain alkyl group of octadecyl group or its branched structure is preferably methyl group.

In a preferred embodiment, the triphenol compound is

(formula a),

(formula b) or

(formula c). The method for preparing this trisphenol compound is not particularly limited, and for example, a method similar to that in the Shegang reference (Synthesis and purification of 1, 1, 1-tris (4-hydroxyphenyl) ethane, proceedings of Tianjin scientific university, 27 (2): 30-33) can be referred to.

In the step a), the mass concentration of the phenolate comprising bisphenol A and the triphenol with a specific structure in the water phase is 10-15%, such as but not limited to 10%, 11%, 12%, 13%, 14%, 15%; wherein, the proportion of the triphenol with a specific structure in the total mass of the phenolate is 0.1-5%, such as but not limited to 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%; the molar ratio of the triphenol in the phenolate is about 0.08-4% under the feed ratio. Alkali metal hydroxide such as but not limited to sodium hydroxide, potassium hydroxide and the like is also added to the aqueous phase containing the phenolate salt, sodium hydroxide is commonly used in the art for adjusting the pH of the aqueous phase to promote phenol ionization, and the pH is controlled to be 11-11.8, such as but not limited to 11, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8; too low a pH can result in the inability of the specific trisphenol and bisphenol components to ionize, affecting the polymerization conversion, while too high a pH can result in an increase in the rate of phosgene alkaline hydrolysis.

This is because: during the preparation of polycarbonate, chloroformate group and phenol oxide anion produce condensation polymerization reaction in oil-water interface, and phenol hydroxyl can participate in the reaction only after being ionized. The two-stage ionization constants of BPA are 9.6 and 10.2 respectively, too low pH results in insufficient ionization, and too high pH results in precipitation of 6-hydrate, such as 16.5 at 25 deg.Cwhen the pH of the aqueous solution of BPA/NaOH in wt% is 12.5, 98% or more of BPA is divalent ionized, and Na appears when the pH reaches 13₂BPA·6H₂And separating out O crystals. In the pH range of the invention, three phenolic hydroxyl groups exist in the specific triphenol component in the step a), the two phenolic hydroxyl groups are completely ionized to participate in interfacial polymerization, but the third phenolic hydroxyl group is most difficult to ionize and cannot participate in reaction, and exists in a molecular chain as an active group. By the design, the hindered phenolic hydroxyl is subsequently reacted with the intermediate shown in the formula I with the phosphoric acid dichlorine end group, so that the conventional linear polycarbonate molecular formula has phosphorus flame-retardant short side groups, and high flame-retardant effect is realized while high-fluidity and low-internal-stress products are obtained.

In step a), the oil phase is usually phosgene dissolved in carbon tetrachloride solvent, and the phosgene is usually dissolved in carbon tetrachloride at a concentration of 7% in the art to form the oil phase, but is not limited to this concentration. Further, in the step a), the total molar amount of phosgene is 1.00 to 1.16 times the sum of the molar amounts of triphenol and bisphenol a having the specific structure, for example, but not limited to, 1 time, 1.01 times, 1.02 times, 1.03 times, 1.04 times, 1.05 times, 1.06 times, 1.07 times, 1.08 times, 1.09 times, 1.1 times, 1.11 times, 1.12 times, 1.13 times, 1.14 times, 1.15 times, and preferably 1.02 to 1.10 times.

In the step a), the water phase and the oil phase are mixed and then are subjected to preliminary reaction to generate polycarbonate low molecular weight oligomer with hindered phenolic hydroxyl active groups, a catalyst is added, chain extension and polymerization are further performed to obtain high molecular weight linear polycarbonate, an end capping agent is added to terminate the polymerization reaction after end capping, and the upper water phase is removed to obtain the high molecular weight linear polycarbonate solution.

Wherein the catalyst may be selected from tertiary amines, quaternary ammonium salts such as triethylamine or combinations of such ammonium salts with one or more phase transfer catalysts. The blocking agent can be added at any stage before the catalyst is added or can be added simultaneously with the catalyst; the end-capping agent may be phenol, p-tert-butylphenol, cumylphenol, octylphenol or other monophenolic species, preferably phenol.

Wherein, the total residence time of the reaction in the step a) is 5-50min, for example, including but not limited to 5min, 10min, 15min, 20min, 25min, 30min, 35min, 40min, 45min, 50min, preferably 5-40min, and more preferably 5-25min, and longer reaction residence time can result in higher polymerization degree of the oligomer and affect the molecular weight control of the final product, the number average molecular weight of the finished product of the invention is controlled at 19000-25000g/mol, and the molecular weight distribution width is controlled at 0.5-2.5.

The reactor of step a) may be a reactor commonly used in photochemical reactions in the art, for example, a reactor comprising at least one tubular mixing reactor, or at least one continuous stirred tank reactor, or a combination thereof may be used

In the step b), the molar ratio of bisphenol A to phosphorus oxychloride is 1: 2.5, for example including but not limited to 2.1, 2.2, 2.3, 2.4, 2.5; the catalyst is one or a combination of calcium chloride, magnesium chloride and magnesium chloride, preferably calcium chloride, and the content of the catalyst is 0.1-0.4% of the mass of the bisphenol A, more preferably 0.15-0.3%, such as but not limited to 0.15%, 0.2%, 0.25%, 0.3%, preferably 0.22%; the catalyst can be removed along with the water phase after the reaction is finished, so that the subsequent influence on the polycarbonate is avoided. The reaction temperature in this step is 100-120 deg.C, including but not limited to 100 deg.C, 105 deg.C, 110 deg.C, 115 deg.C, 120 deg.C, for example; reaction residence times of 3.5 to 6 hours, for example including but not limited to 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours; if the reaction temperature is too low, the reaction speed is too slow, and if the temperature is too high, the number of byproducts is increased; if the time is too short, the reaction is not complete. The reaction pressure in this step is not particularly limited, and may be usually carried out under atmospheric pressure. The reaction in the step is finished until no bubbles are generated (hydrogen chloride gas), and after the reaction is finished, excessive unreacted phosphorus oxychloride is separated out through reflux to obtain a relatively pure intermediate in the formula I;

wherein n is 1 and 2;

in step c), the high molecular weight linear polycarbonate and carbon tetrachloride solution in step a) and the intermediate of formula I in step b) are subjected to interfacial polymerization reaction, which is usually performed in an inert gas atmosphere such as nitrogen, wherein the catalyst is one or a combination of calcium chloride, magnesium chloride and magnesium chloride, preferably calcium chloride, and the amount of the catalyst added is 0.3-0.6%, more preferably 0.4-0.55% of the mass of the triphenol monomer, such as, but not limited to, 0.4%, 0.45%, 0.5%, 0.55%; the reaction temperature in the high-pressure reaction kettle is 130-170 ℃, for example, including but not limited to 130 ℃, 135 ℃, 140 ℃, 145 ℃, 150 ℃, 155 ℃, 160 ℃, 165 ℃, 170 ℃, preferably 145-155 ℃; the reaction residence time is 4 to 6 hours, for example including but not limited to 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, preferably 4.5 to 5.5 hours; the reaction pressure is 5-15atm, preferably 7-12atm, further preferably 8-10atm, such as but not limited to 8atm, 9atm, 10 atm; if the reaction temperature is too low, the reaction speed is too slow, and if the reaction temperature is too high, the number of byproducts is increased, and the color turns yellow; if the time is too short, the reaction is incomplete and the yield of the target product is lowered.

In the step, a reaction kettle contains the high molecular weight linear polycarbonate solution obtained in the step a), the intermediate and the end capping reagent in the formula I are added into the reaction kettle, the addition amount of the intermediate and the end capping reagent is calculated by the mole number of the triphenol in the phenolate in the step a), and the ratio of the mole number of the intermediate in the formula I to the mole number of the triphenol to the mole number of the end capping reagent is 1.01-1.30: 1: 4.04-5.20. After the reaction is stopped, the temperature is reduced and the pressure is reduced to normal temperature and normal pressure, and finally the transparent flame-retardant novel polycarbonate is obtained by removing volatile solvents such as carbon tetrachloride and the like. Specifically, after the reaction is finished, the upper water phase is separated and removed, and then the polymer oil phase solution is washed and separated in multiple steps by adopting dilute sodium hydroxide, dilute hydrochloric acid and desalted water respectively, so that impurities such as residual monomers, catalysts, inorganic salts and the like in the solution are removed to obtain a pure polymer solution. And further adopting a multi-step flash evaporation process to improve the concentration of the polymer in the solution, and finally adopting a double-screw extruder to remove residual solvent under a certain vacuum degree and granulating to obtain the transparent flame-retardant novel polycarbonate resin.

The reaction kettle of the step c) is a continuous stirring kettle type reactor, and can also be a reactor for interfacial polymerization reaction commonly used in the field, for example, a tubular mixing reactor, or a combination of the two.

The transparent flame-retardant novel polycarbonate of the invention can be blended and processed into a polycarbonate molding piece according to the requirements, for example, any antioxidant, plasticizer, leveling agent, flow assistant, heat stabilizer, hydrolysis stabilizer, UV absorbent, antistatic agent, pigment and the like can be added according to the processing requirements.

The transparent flame-retardant novel polycarbonate prepared by the invention can realize different flame-retardant grades of 0.8-3.0mmV0/V1/V2, namely the flame-retardant grades of V0, V1 and V2 under the condition of 0.8mm, and the flame-retardant grades of V0, V1 and V2 under the condition of 3.0mm thickness, so that the transparent flame-retardant novel polycarbonate is greatly improved compared with the prior art for the application of electronic and electric ultrathin transparent windows. The main reason is that the novel polycarbonate of the invention realizes the dispersion of phosphorus elements in polycarbonate at molecular level, and greatly improves the flame retardant property of the final material. In addition, the novel polycarbonate also has good flow processing performance, the melt index aspect of the novel polycarbonate realizes high flow of 7-60g/10min, the processing performance is greatly improved, compared with the prior art, the light transmittance of the polycarbonate is not reduced, the light transmittance is still kept above 87%, and the transparent flame-retardant polycarbonate is very suitable for being used as transparent windows in different fields.

The invention is further illustrated, but not limited, by the following more specific examples.

The main raw materials used in the following examples were respectively:

bisphenol A, technical grade, purchased from chemical industry of Changchun;

sodium hydroxide: analytically pure, purchased from chemical reagents ltd of miuiou, department of Tianjin;

phosgene: industrial grade, homemade;

carbon tetrachloride: analytically pure, purchased from chemical reagents ltd of miuiou, department of Tianjin;

phenol: analytically pure, purchased from chemical research institute of Shandong province;

triethylamine: analytically pure, purchased from chemical reagents ltd of miuiou, department of Tianjin;

hydrochloric acid: the analysis is pure, and the method is purchased from a refined factory in economic and technical development areas of Shandong Laiyang city;

p-tert-butylphenol: analytically pure, purchased from Dainippon ink chemical industries, Inc.;

phosphorus oxychloride: industrial grade, Jiangsu Tianyuan chemical industry;

and drying the final product in a 120 ℃ oven for 4 hours, then performing injection molding on the final product in an injection molding machine at 270 ℃ to obtain sample strips with different standard sizes, and performing tests on transmittance, flame retardant property, impact property and the like.

The melt index was measured using ASTM D1238, conditions 300 ℃/1.2 kg;

the impact performance is tested by adopting an ASTM D256 standard, and the condition is 23 ℃;

the transmittance is tested by adopting the ASTM D1003 standard, and the test thickness is 2 mm;

the flame retardant performance was tested using the UL94 standard.

Preparation example 1: preparation of triphenol compounds of formula a

The specific triphenol compound is synthesized by adopting the following method:

1534g of phenol, 4.08mol of dimethylphenol (or diethylphenol) and 40g of mercaptopropionic acid are added into a 50L reaction kettle with a stirring paddle, 260ml of acetylacetone is dropwise added within 20min of stirring, the temperature is raised to 50 ℃, 50ml of 98% concentrated sulfuric acid is dropwise added within 13min, the system temperature is maintained within the range of 50-53 ℃ for reaction for 30h, then the temperature is lowered to 25 ℃, carbon tetrachloride is added for stirring for 1h, and the mixture is filtered and devolatilized at 78 ℃ to obtain a crude compound mixture.

Adding 600g of the crude product into 3L of 38% methanol aqueous solution for purification, stirring at room temperature for 40min, and filtering to obtain a yellow product; and (3) re-purifying the yellow product 300g in 1.16L of methanol, dropwise adding a 10% KBH4 aqueous solution after stirring is finished until no yellow precipitate is generated, and performing vacuum drying at 70 ℃ to obtain the specific triphenol compound with the purity of 99.9%.

Preparation example 2: preparation of the triphenol compounds of the formula c

1534g of phenol, 4.08mol of diethylphenol and 40g of mercaptopropionic acid are added into a 50L reaction kettle with a stirring paddle, 260ml of acetylacetone is dripped during stirring for 20min, the temperature is raised to 50 ℃, 50ml of 98% concentrated sulfuric acid is dripped during 13min, the system temperature is maintained within the range of 50-53 ℃ for reaction for 30h, then the temperature is lowered to 25 ℃, carbon tetrachloride is added for stirring for 1h, and the mixture is filtered and devolatilized at 78 ℃ to obtain a crude compound mixture.

Preparation example 3: preparation of triphenol compounds of formula b

1534g of phenol, 4.08mol of 2-ethyl-6-methylphenol and 40g of mercaptopropionic acid are added into a 50L reaction kettle with a stirring paddle, 260ml of acetylacetone is dripped in the stirring process within 20min, the temperature is raised to 50 ℃, 50ml of 98% concentrated sulfuric acid is dripped in the stirring process within 13min, the system temperature is maintained within the range of 50-53 ℃ for reaction for 30h, then the temperature is lowered to 25 ℃, carbon tetrachloride is added for stirring for 1h, and the mixture is filtered and devolatilized at 78 ℃ to obtain a crude compound mixture.

Preparation example 4: preparation of intermediates of formula I

The synthesis process of the intermediate I formed in the step b) is as follows:

sequentially adding 0.5g of calcium chloride catalyst and 383.3g of phosphorus oxychloride into a stirred 100L high-pressure kettle type reactor, starting heating and stirring, gradually adding 4566g of bisphenol A solution (with the concentration of 5%) into the reaction process, and filling nitrogen protection gas into the kettle; slowly heating to 110 ℃, and finishing the reaction after the reaction lasts for 5 hours; and (3) distilling the reactant when the temperature of the reactant is reduced to 60 ℃, and removing excessive phosphorus oxychloride to obtain the tetrachlorodiphosphonate-bisphenol A aqueous solution of the intermediate I for later use.

Devolatilization operation:

the operation of the later devolatilization process in the embodiment of the invention is as follows: the oil-water phase after the reaction enters an inclined plate separator to be separated to obtain an upper water phase and a lower oil phase, the lower oil phase is washed by sequentially adopting 0.25 wt% of NaOH, 0.4 wt% of HCl and desalted water with the conductivity less than 0.2us/cm, the flow of washing liquid is 100kg/hr, the polymer concentration is further improved to more than 80% by adopting two-stage flash evaporation, and the operating conditions of the first-stage flash evaporation are as follows: inlet pressure 2MPa (G), temperature 160 ℃, flash tank pressure 0.4MPa (G), temperature 95 ℃; the secondary flash operation conditions were: inlet pressure 7MPa (G), temperature 280 ℃, flash tank pressure 1MPa (G), temperature 240 ℃. And finally, directly feeding the high-temperature solution into a Kobinron ZSK35 type double-screw extruder, removing residual dichloromethane under the vacuum degree of l00mbar, and extruding and granulating to obtain a branched polycarbonate resin product.

Example 1

Mixing and dissolving the trisphenol of the formula a, bisphenol A, sodium hydroxide and water to form a phenol sodium salt aqueous solution, namely an aqueous phase, wherein the total concentration of the phenolate is 10 wt%, the specific trisphenol component accounts for 0.5% of the total phenolate, and the pH is 11.0; phosgene was dissolved in carbon tetrachloride to form an oil phase, with a phosgene concentration of 7%. The water phase, phosgene and carbon tetrachloride are respectively fed into a photochemical reactor consisting of a group of static mixers at the flow rates of 600kg/h, 28.1kg/h and 402kg/h, the inner diameter of the reactor is 54mm, the length of the reactor is 650mm, the reaction residence time is about 5min, and the temperature of a reaction outlet is controlled to be 34 ℃. After the photochemical reaction is finished, the mixture immediately enters a stirring kettle type reactor with two kettles connected in series, 5 wt% of end capping agent p-tert butyl phenol/carbon tetrachloride solution, 30 wt% of sodium hydroxide solution and 1.5 wt% of catalysts triethylamine/carbon tetrachloride solution and carbon tetrachloride are added into a first reaction kettle at the flow rates of 42.0kg/h, 17.0kg/h, 9.5kg/h and 150kg/h respectively, the effective volumes of the reaction kettles are 100L and 600L respectively, the reaction temperature is 35 ℃, and the retention time is 10 min. After the reaction is finished, roughly separating a lower oil phase (the concentration is 15%, the feeding mass is 396.385kg) and the intermediate I aqueous solution (the concentration is 10.8%, the feeding mass is 3.35kg) produced in the step b), respectively feeding the lower oil phase and the intermediate I aqueous solution into a plurality of parallel kettle type reactors with stirring, wherein the addition amount of a catalyst calcium chloride is 1.04g, raising the temperature to 145 ℃ under the nitrogen atmosphere, reacting for 3 hours, adding phenol (the feeding mass is 0.26kg), continuing to react for 1.4 hours, and then finishing the reaction, wherein the reaction pressure is 8 atm; and then preparing the flame-retardant polycarbonate through later-stage devolatilization operation.

Example 2

Mixing and dissolving the trisphenol of the formula a, bisphenol A, sodium hydroxide and water to form a phenol sodium salt aqueous solution, namely an aqueous phase, wherein the total concentration of the phenolate is 15 wt%, the specific trisphenol component accounts for 3% of the total phenolate, and the pH is 11.5; phosgene was dissolved in carbon tetrachloride to form an oil phase, with a phosgene concentration of 7%. The water phase, phosgene and carbon tetrachloride are respectively fed into a photochemical reactor consisting of a group of static mixers at the flow rates of 600kg/h, 41.0kg/h and 586kg/h, the inner diameter of the reactor is 54mm, the length of the reactor is 650mm, the reaction residence time is about 10min, and the temperature of a reaction outlet is controlled to be 34 ℃. After the photochemical reaction is finished, the mixture immediately enters a stirring kettle type reactor with two serially connected kettles, 5 wt% of end capping agent p-tert butyl phenol/carbon tetrachloride solution, 30 wt% of sodium hydroxide solution and 1.5 wt% of catalysts triethylamine/carbon tetrachloride solution and carbon tetrachloride are added into a first reaction kettle at the flow rates of 42.0kg/h, 17.0kg/h, 9.5kg/h and 231kg/h respectively, the effective volumes of the reaction kettles are 100L and 600L respectively, the reaction residence time is 12min, and the reaction temperature is 35 ℃. Roughly separating a lower oil phase (the feeding mass is 380.96kg, the concentration is 15%) after the reaction is finished, respectively feeding the lower oil phase and the intermediate I water solution (the feeding amount is 17.67kg, the concentration is 10.8%) produced in the step b) into a plurality of parallel kettle type reactors with stirring, wherein the adding amount of the catalyst calcium chloride is 4.8g, raising the temperature to 150 ℃ under the nitrogen atmosphere, reacting for 3.5h, then adding the phenol (the feeding amount is 1.37kg), continuing to react for 2h, and finishing the reaction under the reaction pressure of 10 atm; and then preparing the flame-retardant polycarbonate through later-stage devolatilization operation.

Example 3

Mixing and dissolving the trisphenol of the formula a, bisphenol A, sodium hydroxide and water to form a phenol sodium salt aqueous solution, namely an aqueous phase, wherein the total concentration of the phenolate is 12 wt%, the specific trisphenol component accounts for 5% of the total mass of the phenolate, and the pH is 11.8; phosgene was dissolved in carbon tetrachloride to form an oil phase, with a phosgene concentration of 7%. The water phase, phosgene and carbon tetrachloride are respectively fed into a photochemical reactor consisting of a group of static mixers at the flow rates of 600kg/h, 32.1kg/h and 459kg/h, the inner diameter of the reactor is 54mm, the length of the reactor is 650mm, the reaction residence time is about 20min, and the temperature of a reaction outlet is controlled to be 34 ℃. After the photochemical reaction is finished, the mixture immediately enters a stirring kettle type reactor with two serially connected kettles, 5 wt% of end capping agent p-tert butyl phenol/carbon tetrachloride solution, 30 wt% of sodium hydroxide solution and 1.5 wt% of catalysts triethylamine/carbon tetrachloride solution and carbon tetrachloride are added into a first reaction kettle at the flow rates of 42.0kg/h, 17.0kg/h, 9.5kg/h and 185.1kg/h respectively, the effective volumes of the reaction kettles are respectively 100L and 600L, the reaction time is 15min, and the reaction temperature is 35 ℃. Roughly separating a lower oil phase (with the concentration of 15 percent and the feeding mass of 369.02kg) after the reaction is finished and respectively putting an intermediate I aqueous solution (with the concentration of 10.8 percent and the feeding mass of 28.75kg) produced in the step b) into a plurality of parallel kettle type reactors with stirring, wherein the adding amount of a catalyst calcium chloride is 8.73g, raising the temperature to 155 ℃ under the nitrogen atmosphere, reacting for 4 hours, adding 2.23kg of phenol, continuing to react for 1.5 hours, and finishing the reaction, wherein the reaction pressure is 15 atm; and then preparing the flame-retardant polycarbonate through later-stage devolatilization operation.

Example 4

Mixing and dissolving the trisphenol of formula c, bisphenol a, sodium hydroxide and water to form an aqueous phenol sodium salt solution, namely an aqueous phase, wherein the total concentration of the phenolate is 12 wt%, the specific trisphenol component accounts for 1.2% of the total phenolate, and the pH is 11.8; phosgene was dissolved in carbon tetrachloride to form an oil phase, with a phosgene concentration of 7%. The water phase, phosgene and carbon tetrachloride are respectively fed into a photochemical reactor consisting of a group of static mixers at the flow rates of 600kg/h, 33.5kg/h and 477kg/h, the inner diameter of the reactor is 54mm, the length of the reactor is 650mm, the reaction residence time is about 7min, and the reaction outlet temperature is controlled to be 34 ℃. After the photochemical reaction is finished, the mixture immediately enters a stirring kettle type reactor with two kettles connected in series, 5 wt% of end capping agent p-tert butyl phenol/carbon tetrachloride solution, 30 wt% of sodium hydroxide solution and 1.5 wt% of catalysts triethylamine/carbon tetrachloride solution and carbon tetrachloride are added into a first reaction kettle at the flow rates of 42.0kg/h, 17.0kg/h, 9.5kg/h and 177.1kg/h respectively, the effective volumes of the reaction kettles are 100L and 600L respectively, the reaction temperature is 35 ℃, and the retention time is 16 min. After the reaction is finished, roughly separating a lower oil phase (the feeding mass is 392.54kg, the concentration is 15 percent) and an intermediate I water solution (the feeding mass is 6.93kg, the concentration is 10.8 percent) produced in the step b) respectively enter a plurality of parallel stirred tank reactors, the adding amount of a catalyst calcium chloride is 2.72g, the temperature is raised to 170 ℃ in a nitrogen atmosphere, phenol with the mass of 0.54kg is added after the reaction is carried out for 4 hours, the reaction is continued for 1.5 hours and then is finished, and the reaction pressure is 15 atm; and then preparing the flame-retardant polycarbonate through later-stage devolatilization operation.

Example 5

Mixing and dissolving the trisphenol of formula b, bisphenol a, sodium hydroxide and water to form a phenol sodium salt aqueous solution, namely an aqueous phase, wherein the total concentration of the phenolate is 15 wt%, the specific trisphenol component accounts for 3.5% of the total phenolate, and the pH is 11.8; phosgene was dissolved in carbon tetrachloride to form an oil phase, with a phosgene concentration of 7%. The water phase, phosgene and carbon tetrachloride are respectively fed into a photochemical reactor consisting of a group of static mixers at the flow rates of 600kg/h, 42.2kg/h and 603kg/h, the inner diameter of the reactor is 54mm, the length of the reactor is 650mm, the reaction residence time is about 13min, and the reaction outlet temperature is controlled to be 34 ℃. After the photochemical reaction is finished, the mixture immediately enters a stirring kettle type reactor with two serially connected kettles, 5 wt% of end capping agent p-tert-butylphenol/carbon tetrachloride solution, 30 wt% of sodium hydroxide solution and 1.5 wt% of catalysts triethylamine/carbon tetrachloride solution and carbon tetrachloride are added into a first reaction kettle at the flow rates of 42.0kg/h, 17.0kg/h, 9.5kg/h and 229.1kg/h respectively, the effective volumes of the reaction kettles are 100L and 600L respectively, the reaction time is 12min, and the reaction temperature is 35 ℃. After the reaction is finished, roughly separating a lower oil phase (the feeding mass is 378.09kg, the concentration is 15 percent) and the water solution (the feeding mass is 20.33kg, the concentration is 10.8 percent) in the middle I produced in the step b) respectively enter a plurality of parallel kettle type reactors with stirring, the adding amount of the catalyst calcium chloride is 4.87g, the temperature is raised to 140 ℃ in the nitrogen atmosphere, phenol with the mass of 1.58kg is added after the reaction is carried out for 3.5h, the reaction is finished after the reaction is continued for 1.5h, and the reaction pressure is 7 atm; and then preparing the flame-retardant polycarbonate through later-stage devolatilization operation.

Example 6

Mixing and dissolving the trisphenol of the formula a, bisphenol A, sodium hydroxide and water to form a phenol sodium salt aqueous solution, namely an aqueous phase, wherein the total concentration of the phenolate is 13 wt%, the specific trisphenol component accounts for 0.1% of the total phenolate, and the pH is 11.8; phosgene was dissolved in carbon tetrachloride to form an oil phase, with a phosgene concentration of 7%. The water phase, phosgene and carbon tetrachloride are respectively fed into a photochemical reactor consisting of a group of static mixers at the flow rates of 600kg/h, 38.9kg/h and 555.8kg/h, the inner diameter of the reactor is 54mm, the length of the reactor is 650mm, the reaction residence time is about 5min, and the reaction outlet temperature is controlled to be 34 ℃. After the photochemical reaction is finished, the mixture immediately enters a stirring kettle type reactor with two kettles connected in series, 5 wt% of end capping agent p-tert butyl phenol/carbon tetrachloride solution, 30 wt% of sodium hydroxide solution and 1.5 wt% of catalysts triethylamine/carbon tetrachloride solution and carbon tetrachloride are added into a first reaction kettle at the flow rates of 42.0kg/h, 17.0kg/h, 9.5kg/h and 174.3kg/h respectively, the effective volumes of the reaction kettles are 100L and 600L respectively, the reaction temperature is 35 ℃, and the retention time is 10 min. After the reaction is finished, roughly separating a lower oil phase (the feeding mass is 399.16kg, the concentration is 15 percent) and an intermediate I water solution (the feeding mass is 0.78kg, the concentration is 10.8 percent) produced in the step b) respectively enter a plurality of parallel kettle type reactors with stirring, adding 0.25g of catalyst calcium chloride, raising the temperature to 130 ℃ in a nitrogen atmosphere, reacting for 3 hours, adding 0.06kg of phenol, continuing to react for 1 hour, and finishing the reaction at the reaction pressure of 5 atm; and then preparing the flame-retardant polycarbonate through later-stage devolatilization operation.

Comparative example 1

PC with MI of 10 and 5% phosphorus flame retardant BDP were pelletized by co-extrusion in an extruder, and then subjected to physical property test.

Comparative example 2

PC with MI of 20 was pelletized by co-extrusion with 0.2% sulfonate flame retardant PFBS in an extruder, followed by physical property test.

Comparative example 3

PC having MI of 10 and 3% phosphorus flame retardant BDP were pelletized by co-extrusion in an extruder, and then subjected to physical property test.

Comparative example 4

Compared with the embodiment 5, the proportion of the specific triphenol is increased from 3.5 percent to 5.5 percent, and other feeding proportions are kept unchanged, specifically as follows:

triphenol of formula b, bisphenol a, sodium hydroxide and water were mixed and dissolved to form an aqueous solution of phenol sodium salt, i.e. an aqueous phase, wherein the total concentration of phenolate was 15 wt%, the specific triphenol component accounted for 5.5% of the total phenolate, and phosgene was dissolved in carbon tetrachloride at pH 11.8 to form an oil phase, wherein the concentration of phosgene was 7%. The water phase, phosgene and carbon tetrachloride are respectively fed into a photochemical reactor consisting of a group of static mixers at the flow rates of 600kg/h, 41kg/h and 586kg/h, the inner diameter of the reactor is 54mm, the length of the reactor is 650mm, the reaction residence time is about 13min, and the temperature of a reaction outlet is controlled to be 34 ℃. After the photochemical reaction is finished, the mixture immediately enters a stirring kettle type reactor with two serially connected kettles, 5 wt% of end capping agent p-tert butyl phenol/carbon tetrachloride solution, 30 wt% of sodium hydroxide solution and 1.5 wt% of catalysts triethylamine/carbon tetrachloride solution and carbon tetrachloride are added into a first reaction kettle at the flow rates of 42.0kg/h, 17.0kg/h, 9.5kg/h and 238.1kg/h respectively, the effective volumes of the reaction kettles are 100L and 600L respectively, the reaction time is 12min, and the reaction temperature is 35 ℃. After the reaction is finished, roughly separating a lower oil phase (the concentration is 15%, the mass of the fed material is 366.62kg) and the aqueous solution (the concentration is 10.8%, the mass is 30.98kg) of the intermediate I produced in the step b) to respectively enter a plurality of parallel kettle type reactors with stirring, adding a catalyst of calcium chloride with the content of 116.7g, raising the temperature to 140 ℃ in a nitrogen atmosphere to react for 3.5h, adding 2.4kg of phenol, continuing to react for 1.5h, and finishing the reaction at the reaction pressure of 7 atm; and then preparing the flame-retardant polycarbonate through later-stage devolatilization operation.

Comparative example 5

Compared with example 2, the flame retardant polycarbonate is prepared by adding no trisphenol and the other conditions are completely the same.

The data for the physical property tests carried out on the polycarbonate specimens of the examples and comparative examples are compared as follows:

name (R)	Impact performance	Flame retardant properties	Melt index	Transmittance of light
					Example 1	800	3.0V2	9	88
Example 2	600	1.2V0	20	87
					Example 3	510	0.8V0	45	88
Example 4	750	2.0V1	15	89
					Example 5	570	1.0V1	27	87
Example 6	820	3.0V2	7	88
					Comparative example 1	200	1.2V0	18	88
Comparative example 2	750	3.0V1	20	87
					Comparative example 3	450	1.5V1	15	87
Comparative example 4	310	0.8V0	62	85
					Comparative example 5	830	3.0HB	6.5	89

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. It will be appreciated by those skilled in the art that modifications or adaptations to the invention may be made in light of the teachings of the present specification. Such modifications or adaptations are intended to be within the scope of the present invention as defined in the claims.

Claims

1. A preparation method of novel transparent flame-retardant polycarbonate is characterized by comprising the following steps:

a) carrying out photochemical reaction on a phenolate aqueous phase formed by dissolving bisphenol A and triphenol in alkali liquor and an oil phase formed by dissolving phosgene in carbon tetrachloride to prepare a polycarbonate oligomer with hindered phenolic hydroxyl active groups, and then adding a catalyst and an end capping agent to react to obtain a high molecular weight linear polycarbonate solution;

2. The method according to claim 1, wherein the triphenol in step a) has a general structural formula shown in formula II:

wherein R is₁、R₂Each independently selected from alkyl with carbon atom number of 2-18 or one or combination of benzene ring and naphthalene ring, preferably methyl or ethyl; r₃Selected from hydrocarbon groups having a carbon number of 2 to 18, preferably methyl.

3. The preparation method according to claim 1 or 2, characterized in that the mass concentration of the phenolate in the phenolate aqueous phase in the step a) is 10-15%, and the ratio of the triphenol in the total mass of the phenolate is 0.1-5%; preferably, the lye is an aqueous solution of an alkali metal hydroxide, more preferably an aqueous sodium hydroxide solution; the pH value of the phenolate aqueous phase is controlled to 11-11.8.

4. The preparation method according to any one of claims 1 to 3, wherein the reaction in step a) has a residence time of 5 to 50min, preferably 5 to 40min, more preferably 5 to 25 min; preferably, the total molar amount of phosgene in step a) is 1.00-1.16 times, preferably 1.02-1.10 times the sum of the molar amounts of triphenol and bisphenol A.

5. The process according to claim 1 or 2, wherein the molar ratio of bisphenol a to phosphorus oxychloride in step b) is 1: 2.5, the catalyst is selected from any one or a combination of calcium chloride and magnesium chloride, preferably calcium chloride, and the addition amount of the catalyst is 0.1-0.4%, preferably 0.15-0.3% of the mass of the bisphenol A; preferably, the reaction temperature in step b) is 100-120 ℃; the reaction residence time is 3.5-6 h.

6. The method according to claim 1 or 2, wherein the inert atmosphere in step c) is nitrogen atmosphere, and the reaction temperature in the reaction kettle is 130-170 ℃, preferably 145-155 ℃; the reaction residence time is 4 to 6 hours, preferably 4.5 to 5.5 hours; the reaction pressure is 5 to 15atm, preferably 7 to 12atm, more preferably 8 to 10 atm.

7. The preparation method according to claim 6, wherein the catalyst in step c) is selected from any one or combination of calcium chloride and magnesium chloride, preferably calcium chloride, and the addition amount of the catalyst is 0.3-0.6%, preferably 0.4-0.55% of the mass of the triphenol monomer in step a); the end-capping agent is selected from p-tert-butylphenol or phenol, preferably phenol.

8. The process according to claim 7, wherein the intermediate of formula I and the blocking agent are added in step c) in an amount such that the ratio of the number of moles of intermediate of formula I, the number of moles of triphenol and the number of moles of blocking agent, based on the number of moles of triphenol in the phenoxide in step a), is from 1.01 to 1.3: 1: 4.04-5.20.

9. A transparent flame-retardant novel polycarbonate which is characterized by being prepared by the preparation method of any one of claims 1 to 8; preferably, the novel polycarbonate can realize the flame retardant grade of 0.8-3.0mmV0/V1/V2, the melt index is 7-60g/10min, the light transmittance is more than 87%, and the impact property reaches 500-900J/m.

10. The novel polycarbonate prepared by the preparation method of any one of claims 1 to 8 or the novel polycarbonate of claim 9 is applied to a transparent window, preferably to a transparent window in the field of electronics and electrical.