Hydrogenated bisphenol A polycarbonate with low chroma and high molecular weight and preparation method thereof

Abstract

The invention discloses low-chroma and high-molecular-weight hydrogenated bisphenol A polycarbonate and a preparation method thereof, and the preparation method comprises the following steps: hydrogenated bisphenol A and a sulfonylation reagent are subjected to a reaction in an organic alkali, a low-temperature environment and a stirring condition, and purification is performed to obtain disulfonate; the preparation method comprises the following steps: carrying out melt transesterification reaction on disulfonate, diphenyl carbonate and aliphatic dihydric alcohol in the presence of a basic catalyst, carrying out polycondensation reaction after the reaction is finished, and carrying out bracing, cooling and pelletizing on the reaction product to obtain the hydrogenated bisphenol A polycarbonate with low chroma and high molecular weight, according to the preparation method disclosed by the invention, a strong electron-withdrawing reagent (sulfonylation reagent) is introduced to activate a hydroxyl bond of hydrogenated bisphenol A, so that the reaction efficiency is improved; the strong electron-withdrawing reagent enables oxygen atoms of hydroxyl to have positive electricity through an electron-withdrawing effect, so that the strong electron-withdrawing reagent is more easily attacked by a nucleophilic reagent and is promoted to leave in transesterification, and polycarbonate with high molecular weight can be synthesized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polycarbonate, in particular to a low-colority, high-molecular-weight hydrogenated bisphenol A polycarbonate and a preparation method thereof. BACKGROUND

[0002] The bisphenol A (BPA) in the traditional polycarbonate preparation process is prone to decomposition under the action of high temperature and alkaline catalyst to produce colored impurities such as isopropenyl phenol (IPP), which causes the polycarbonate product to turn yellow, affecting its optical properties and market competitiveness. Hydrogenated bisphenol A (HBPA) is the product of catalytic hydrogenation of bisphenol A, and is an important new type of resin raw material in the field of fine chemicals. The application fields of hydrogenated bisphenol A and bisphenol A are basically the same. After replacing the benzene ring structure in the above polymer molecular backbone with a saturated six-membered ring structure, the sensitivity of the original double bond to ultraviolet light and the resulting breakage defects can be overcome, and good weather resistance, corona resistance, tracking resistance, high dielectric strength, and chemical resistance can be exhibited. At the same time, the saturated six-membered ring structure increases the conformation of the chemical bond connected thereto, making the main chain less prone to microcrystals, thereby greatly increasing the light transmittance of the polymer. Therefore, HBPA is non-toxic and resistant to ultraviolet light, and is an ideal monomer for replacing BPA to synthesize PC.

[0003] Hydrogenated bisphenol A polycarbonate (HBPA-PC) is a new type of bio-based polycarbonate. Due to its excellent properties such as non-toxicity, chemical stability, ultraviolet resistance, thermal stability, and weather resistance, it is widely used in optical materials, electronic appliances, automotive interiors, and other fields.

[0004] However, research by East China University of Technology shows that hydrogenated bisphenol A is difficult to dissociate into a nucleophile in the ester exchange reaction due to the weak alkaline nature of the secondary alcohol, resulting in lower reactivity than bisphenol A, making it more difficult to synthesize high-molecular-weight HBPA-PC. How to synthesize low-colority, high-transmittance, and high-molecular-weight HBPA-PC is a key problem.

[0005] Therefore, the present application is proposed. SUMMARY

[0006] The present application aims to provide a low-colority, high-molecular-weight hydrogenated bisphenol A polycarbonate and a preparation method thereof. The preparation method activates the hydroxyl bond of hydrogenated bisphenol A by introducing a strong electron-withdrawing reagent, thereby improving the reaction efficiency. The strong electron-withdrawing reagent makes the oxygen atom of the hydroxyl group more positively charged through electron-withdrawing effect, making it more susceptible to attack by nucleophiles and facilitating the departure in the ester exchange reaction, thereby enabling the synthesis of high-molecular-weight polycarbonate.

[0007] In order to achieve the above-mentioned purpose of the present application, the following technical solutions are adopted:

[0008] The first aspect of the present application provides a method for preparing low-color high molecular weight hydrogenated bisphenol A polycarbonate, comprising the following steps:

[0009] (a) reacting hydrogenated bisphenol A with a sulfonylating agent in an organic base, low temperature environment and stirring conditions, purifying to obtain a bis-sulfonate;

[0010] (b) performing melt transesterification of the bis-sulfonate, diphenyl carbonate and aliphatic diol under the condition of an alkaline catalyst, and after the reaction is completed, drawing, cooling and granulating the product to obtain the low-color high molecular weight hydrogenated bisphenol A polycarbonate.

[0011] Preferably, in the step (a), the sulfonylating agent is selected from at least one of benzene sulfonyl chloride, methyl sulfonyl chloride, ethyl sulfonyl chloride, p-toluene sulfonyl chloride, 2-pyridine sulfonyl fluoride, chlorinated nonafluoro butyl sulfonyl, sulfonyl hydrazine and chlorosulfonyl isocyanate.

[0012] Preferably, in the step (a), the molar ratio of hydrogenated bisphenol A to the sulfonylating agent is 1:(2-4), and the molar ratio of the organic base to the sulfonylating agent is 1:(0.2-0.5).

[0013] The organic base is selected from at least one of triethylamine, pyridine and piperidine.

[0014] Preferably, in the step (a), the low temperature environment is 0-5℃, the stirring rate is 200-600 rpm, and the reaction time is 3-4 h.

[0015] Preferably, in the step (b), the aliphatic diol is selected from at least one of ethylene glycol, 1,4-cyclohexane dimethanol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol and 1,8-octanediol.

[0016] Preferably, in the step (b), the alkaline catalyst is selected from at least one of sodium methoxide, potassium methoxide, Lewis base catalyst, lithium chloride and lithium acetylacetonate.

[0017] Preferably, in the step (b), the molar ratio of the sum of the bis-sulfonate and the aliphatic diol to the diphenyl carbonate is 1:(1-1.06).

[0018] The molar ratio of the bis-sulfonate to the aliphatic diol is 1:(0.2-1).

[0019] Preferably, in the step (b), the transesterification reaction conditions are: temperature 180℃-200℃, stirring rate 100-200 rpm, reaction time 3-4 h, and reaction pressure -0.04 to -0.06 MPa.

[0020] Preferably, in the step (b), the amount of the basic catalyst added is 2-10 ppm of the final product calculated based on the central metal atom.

[0021] The second aspect of the present application provides a low-color high-molecular-weight hydrogenated bisphenol A polycarbonate prepared by the above preparation method.

[0022] Compared with the prior art, the present application has at least the following beneficial effects:

[0023] The preparation method of the present application activates the hydroxyl bond of hydrogenated bisphenol A by introducing a strong electron-withdrawing reagent (sulfonylating reagent), thereby improving the reaction efficiency; the strong electron-withdrawing reagent makes the oxygen atom of the hydroxyl group more positively charged through electron-withdrawing effect, thereby being more easily attacked by a nucleophile, promoting the leaving in the transesterification reaction, and enabling the synthesis of high-molecular-weight polycarbonates. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the specific embodiments or prior art description will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale.

[0025] Figure 1 The molecular weight diagram of the low-color high-molecular-weight hydrogenated bisphenol A polycarbonate prepared for Example 1 of the present application. DETAILED DESCRIPTION

[0026] The embodiments of the technical solutions of the present application will be described in detail below in combination with examples. The following examples are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, but cannot limit the protection scope of the present application.

[0027] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the present application should be understood as the usual meanings understood by the skilled person in the field to which the present application belongs.

[0028] The embodiments of the present application provide a preparation method of a low-color high-molecular-weight hydrogenated bisphenol A polycarbonate, which comprises the following steps:

[0029] (a) reacting hydrogenated bisphenol A with a sulfonylating reagent in the presence of an organic base, under low-temperature conditions and stirring, and purifying to obtain a bis-sulfonate;

[0030] (b) performing melt transesterification reaction of the bis-sulfonate, diphenyl carbonate and aliphatic diol in the presence of a basic catalyst, and after the reaction is completed, the product is drawn, cooled and granulated to obtain the low-color high-molecular-weight hydrogenated bisphenol A polycarbonate.

[0031] The preparation method of the present application activates the hydroxyl bond of hydrogenated bisphenol A by introducing a strong electron-withdrawing reagent (sulfonylating reagent) to improve the reaction efficiency; the strong electron-withdrawing reagent can make the oxygen atom of the hydroxyl group more positive through electron-withdrawing effect, so that it is more easily attacked by a nucleophile, promoting the leaving in the ester exchange reaction, and enabling the synthesis of high molecular weight polycarbonate.

[0032] In an embodiment, in the step (a), the sulfonylating reagent is selected from at least one of benzene sulfonyl chloride, methyl sulfonyl chloride, ethyl sulfonyl chloride, p-toluenesulfonyl chloride, 2-pyridine sulfonyl fluoride, chlorinated nonafluorobutylsulfonyl, sulfonyl hydrazine and chlorosulfonyl isocyanate.

[0033] In an embodiment, in the step (a), the molar ratio of hydrogenated bisphenol A to the sulfonylating reagent is 1:(2-4); the molar ratio of the organic base to the sulfonylating reagent is 1:(0.2-0.5).

[0034] The organic base is selected from at least one of triethylamine, pyridine and piperidine.

[0035] Preferably, in the step (a), the low-temperature environment is 0-5℃; the stirring rate is 200-600 rpm, and the reaction time is 3-4 h.

[0036] In an embodiment, in the step (b), the aliphatic diol is selected from at least one of ethylene glycol, 1,4-cyclohexane dimethanol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol and 1,8-octanediol.

[0037] In an embodiment, in the step (b), the basic catalyst is selected from at least one of sodium methoxide, potassium methoxide, Lewis base catalyst, lithium chloride and lithium acetylacetonate.

[0038] In an embodiment, in the step (b), the molar ratio of the sum of the bis-sulfonate and the aliphatic diol to the diphenyl carbonate is 1:(1-1.06).

[0039] The molar ratio of the bis-sulfonate and the aliphatic diol is 1:(0.2-1).

[0040] In an embodiment, in the step (b), the ester exchange reaction conditions are: the temperature is 180℃-200℃, the stirring rate is 100-200 rpm, the reaction time is 3-4 h, and the reaction pressure is -0.04 to -0.06 MPa.

[0041] In an embodiment, in the step (b), the addition amount of the basic catalyst is 2-10 ppm of the final product calculated based on the central metal atom.

[0042] Another embodiment of the present application provides a low-color high molecular weight hydrogenated bisphenol A polycarbonate prepared by the above method.

[0043] The technical solutions of the present application are further described in detail below through specific embodiments.

[0044] Embodiment 1

[0045] The present embodiment is a preparation method of a low-color high molecular weight hydrogenated bisphenol A polycarbonate, which comprises the following steps:

[0046] (a) hydrogenated bisphenol A and toluene are simultaneously added to a round-bottom flask under ice bath conditions, stirring is started to make the hydrogenated bisphenol A completely dissolved; after the raw materials are completely dissolved, triethylamine is added to the flask, p-toluenesulfonyl chloride is slowly added dropwise through a constant-pressure funnel, and ice bath reaction is carried out for 4 hours; after the reaction is completed, the reaction liquid is poured into a separatory funnel, deionized water is added for liquid-liquid extraction, which is repeated 4 times, the toluene organic phase is combined, and toluene is removed through a rotary evaporator to obtain white solid; the white solid is dissolved in ethanol, and low-temperature precipitation is repeated 4 times to obtain bis-sulfonyl ester, wherein the molar ratio of hydrogenated bisphenol A to p-toluenesulfonyl chloride is 1:3, and the molar ratio of triethylamine to p-toluenesulfonyl chloride is 1:0.3;

[0047] (b) 1097.36 g of bis-sulfonic acid ester, 288.42 g of 1,4-cyclohexanedimethanol, 908.27 g of diphenyl carbonate, and an alkaline catalyst are added to a reaction kettle, the alkaline catalyst is lithium acetylacetonate, and the amount is 5 ppm of lithium, the central metal atom, based on the weight of the final product; after nitrogen replacement, the temperature is raised to 190°C, the pressure is controlled at -0.05 Mpa, and the stirring rate is 150 rpm; after 3 hours of reaction, a prepolymer is obtained; after esterification is completed, a polycondensation reaction is carried out, which is divided into two stages of low vacuum and high vacuum; in the low vacuum stage, the vacuum degree is controlled at 1000 pa, the kettle temperature is controlled at 220°C, the stirring rate is 100 rpm, and the residence time is 50 min; then it enters the high vacuum stage, the vacuum degree is controlled at 80 pa, the kettle temperature is controlled at 220°C, the stirring rate is 100 rpm, and the polycondensation reaction is carried out for 1 h before discharging; then, after drawing, cooling, and granulating, the low-color high molecular weight hydrogenated bisphenol A polycarbonate is obtained.

[0048] Embodiment 2

[0049] The present embodiment is a preparation method of a low-color high molecular weight hydrogenated bisphenol A polycarbonate, which comprises the following steps:

[0050] (a) under ice bath condition, hydrogenated bisphenol A and toluene are simultaneously added into a round bottom flask, stirring is started to make hydrogenated bisphenol A completely dissolved; after the raw materials are completely dissolved, triethylamine is added into the flask, p-toluenesulfonyl chloride is slowly added dropwise through a constant pressure funnel, ice bath reaction is carried out for 4 hours; after the reaction is completed, the reaction liquid is poured into a separatory funnel, deionized water is added for liquid separation extraction, the operation is repeated for 4 times, the toluene organic phase is combined, toluene is removed through a rotary evaporator, white solid is obtained; the white solid is dissolved in ethanol, low-temperature precipitation is continuously carried out, the operation is repeated for 4 times, a bis-sulfonyl ester is obtained, wherein the molar ratio of hydrogenated bisphenol A to p-toluenesulfonyl chloride is 1:3; the molar ratio of triethylamine to p-toluenesulfonyl chloride is 1:0.3;

[0051] (b) 1316.832g of the bis-sulfonic acid ester, 230.736g of 1,4-cyclohexanedimethanol, 908.27g of diphenyl carbonate and a basic catalyst are added into a reaction kettle, the basic catalyst is lithium acetylacetonate, the amount is 5ppm of lithium, which is the central metal atom, based on the weight of the final product. After replacing nitrogen, the temperature is raised to 190°C, the pressure is controlled at-0.05Mpa, the stirring speed is 150rpm, and the prepolymer is obtained after 3 hours of reaction; after esterification is completed, polycondensation reaction is carried out, which is divided into two stages of low vacuum and high vacuum; in the low vacuum stage, the vacuum degree is controlled at 1000pa, the kettle temperature is controlled at 220°C, the stirring speed is 100rpm, and the residence time is 50min; then it enters the high vacuum stage, the vacuum degree is controlled at 80pa, the kettle temperature is controlled at 220°C, the stirring speed is 100rpm, and the polycondensation reaction is carried out for 1h before discharging; then through drawing, cooling and granulation, the low-color high-molecular-weight hydrogenated bisphenol A polycarbonate is obtained.

[0052] Example 3

[0053] The embodiment is a preparation method of a low-color high-molecular-weight hydrogenated bisphenol A polycarbonate, which comprises the following steps:

[0054] (a) under ice bath condition, hydrogenated bisphenol A and toluene are simultaneously added into a round bottom flask, stirring is started to make hydrogenated bisphenol A completely dissolved; after the raw materials are completely dissolved, triethylamine is added into the flask, p-toluenesulfonyl chloride is slowly added dropwise through a constant pressure funnel, ice bath reaction is carried out for 4 hours; after the reaction is completed, the reaction liquid is poured into a separatory funnel, deionized water is added for liquid separation extraction, the operation is repeated for 4 times, the toluene organic phase is combined, toluene is removed through a rotary evaporator, white solid is obtained; the white solid is dissolved in ethanol, low-temperature precipitation is continuously carried out, the operation is repeated for 4 times, a bis-sulfonyl ester is obtained, wherein the molar ratio of hydrogenated bisphenol A to p-toluenesulfonyl chloride is 1:3; the molar ratio of triethylamine to p-toluenesulfonyl chloride is 1:0.3;

[0055] (b) adding 1536.304 g of bis-sulfonate, 173.052 g of 1,4-cyclohexane dimethanol, 908.27 g of diphenyl carbonate and a basic catalyst, which is lithium acetylacetonate, into a reaction kettle, the amount of which is 5 ppm of lithium, the central metal atom, based on the weight of the final product. After replacing nitrogen, the temperature is raised to 190°C, the pressure is controlled at -0.05 Mpa, and the stirring rate is 150 rpm. The prepolymer is obtained after 3 hours of reaction. After esterification, the polycondensation reaction is carried out in two stages, i.e., low vacuum and high vacuum. In the low vacuum stage, the vacuum degree is controlled at 1000 pa, the temperature in the kettle is controlled at 220°C, the stirring rate is 100 rpm, and the residence time is 50 min. Then, it enters the high vacuum stage, in which the vacuum degree is controlled at 80 pa, the temperature in the kettle is controlled at 220°C, and the stirring rate is 100 rpm. The polycondensation reaction is carried out for 1 hour, and then the product is discharged. After drawing, cooling and granulating, the low-color high-molecular-weight hydrogenated bisphenol A polycarbonate is obtained.

[0056] Example 4

[0057] The present embodiment is a method for preparing low-color high-molecular-weight hydrogenated bisphenol A polycarbonate, which comprises the following steps:

[0058] (a) under ice bath conditions, hydrogenated bisphenol A and toluene are simultaneously added to a round-bottom flask, and stirring is started to make the hydrogenated bisphenol A completely dissolved. After the raw materials are completely dissolved, triethylamine is added to the flask, and p-toluenesulfonyl chloride is slowly added dropwise through a constant-pressure funnel. The ice bath reaction is carried out for 4 hours. After the reaction is completed, the reaction liquid is poured into a separatory funnel, deionized water is added for liquid separation extraction, which is repeated 4 times. The toluene organic phase is combined, and toluene is removed by a rotary evaporator to obtain white solid. The white solid is dissolved in ethanol, and is repeatedly precipitated at low temperature 4 times to obtain bis-sulfonate. The molar ratio of hydrogenated bisphenol A to p-toluenesulfonyl chloride is 1:3, and the molar ratio of triethylamine to p-toluenesulfonyl chloride is 1:0.3;

[0059] (b) 480.76 g of hydrogenated bisphenol A, 288.42 g of 1,4-cyclohexanedimethanol, 908.27 g of diphenyl carbonate and a basic catalyst are added into a reaction kettle, the basic catalyst is lithium acetylacetonate, the amount of which is 5 ppm of the final product weight calculated based on the central metal atom lithium; after replacing nitrogen, the temperature is raised to 190°C, the pressure is controlled at -0.05 Mpa, the stirring rate is 150 rpm, and the prepolymer is obtained after 3 hours of reaction; after esterification is completed, the polycondensation reaction is carried out, which is divided into two stages of low vacuum and high vacuum; in the low vacuum stage, the vacuum degree is controlled at 1000 pa, the kettle temperature is controlled at 220°C, the stirring rate is 100 rpm, and the residence time is 50 min; then it enters the high vacuum stage, the vacuum degree is controlled at 80 pa, the kettle temperature is controlled at 220°C, the stirring rate is 100 rpm, and the polycondensation reaction is carried out for 1 h before discharging; then it is drawn, cooled and cut into particles to obtain the low-color high-molecular-weight hydrogenated bisphenol A polycarbonate.

[0060] Comparative Example 1

[0061] The present comparative example is a preparation method of hydrogenated bisphenol A polycarbonate, which comprises the following steps:

[0062] (a) 480.76 g of hydrogenated bisphenol A, 288.42 g of 1,4-cyclohexanedimethanol, 908.27 g of diphenyl carbonate and a basic catalyst are added into a reaction kettle, the basic catalyst is lithium acetylacetonate, the amount of which is 5 ppm of the final product weight calculated based on the central metal atom lithium; after replacing nitrogen, the temperature is raised to 190°C, the pressure is controlled at -0.05 Mpa, the stirring rate is 150 rpm, and the prepolymer is obtained after 3 hours of reaction; after esterification is completed, the polycondensation reaction is carried out, which is divided into two stages of low vacuum and high vacuum; in the low vacuum stage, the vacuum degree is controlled at 1000 pa, the kettle temperature is controlled at 220°C, the stirring rate is 100 rpm, and the residence time is 50 min; then it enters the high vacuum stage, the vacuum degree is controlled at 80 pa, the kettle temperature is controlled at 220°C, the stirring rate is 100 rpm, and the polycondensation reaction is carried out for 1 h before discharging; then it is drawn, cooled and cut into particles to obtain the low-color high-molecular-weight hydrogenated bisphenol A polycarbonate.

[0063] Comparative Example 2

[0064] The present comparative example is a preparation method of hydrogenated bisphenol A polycarbonate, which comprises the following steps:

[0065] (a) 673.064 g of hydrogenated bisphenol A, 173.052 g of 1,4-cyclohexane dimethanol, 908.27 g of diphenyl carbonate and a basic catalyst were added into a reaction kettle, the basic catalyst was lithium acetylacetonate, the amount of which was 5 ppm of the final product weight calculated based on the central metal atom lithium; after replacing nitrogen, the temperature was raised to 190°C, the pressure was controlled at -0.05 Mpa, and the stirring rate was 150 rpm, and the prepolymer was obtained after 3 hours of reaction; after esterification was completed, the polycondensation reaction was carried out, which was divided into two stages of low vacuum and high vacuum; in the low vacuum stage, the vacuum degree was controlled at 1000 pa, the kettle temperature was controlled at 220°C, the stirring rate was 100 rpm, and the residence time was 50 min; then it entered the high vacuum stage, the vacuum degree was controlled at 80 pa, the kettle temperature was controlled at 220°C, the stirring rate was 100 rpm, and the polycondensation reaction was carried out for 1 h before discharging; then it was drawn, cooled and cut into particles to obtain the low-color high-molecular-weight hydrogenated bisphenol A polycarbonate.

[0066] Comparative Example 3

[0067] The present comparative example is a preparation method of hydrogenated bisphenol A polycarbonate, which comprises the following steps:

[0068] (a) 673.064 g of hydrogenated bisphenol A, 173.052 g of 1,4-cyclohexane dimethanol, 908.27 g of diphenyl carbonate and a basic catalyst were added into a reaction kettle, the basic catalyst was lithium acetylacetonate, the amount of which was 5 ppm of the final product weight calculated based on the central metal atom lithium; after replacing nitrogen, the temperature was raised to 190°C, the pressure was controlled at -0.05 Mpa, and the stirring rate was 150 rpm, and the prepolymer was obtained after 3 hours of reaction; after esterification was completed, the polycondensation reaction was carried out, which was divided into two stages of low vacuum and high vacuum; in the low vacuum stage, the vacuum degree was controlled at 1000 pa, the kettle temperature was controlled at 220°C, the stirring rate was 100 rpm, and the residence time was 50 min; then it entered the high vacuum stage, the vacuum degree was controlled at 80 pa, the kettle temperature was controlled at 220°C, the stirring rate was 100 rpm, and the polycondensation reaction was carried out for 1 h before discharging; then it was drawn, cooled and cut into particles to obtain the low-color high-molecular-weight hydrogenated bisphenol A polycarbonate.

[0069] Comparative Example 4

[0070] The present comparative example is a preparation method of hydrogenated bisphenol A polycarbonate, which comprises the following steps:

[0071] (a) 384.608 g of hydrogenated bisphenol A, 346.104 g of 1,4-cyclohexane dimethanol, 908.27 g of diphenyl carbonate and a basic catalyst, which is lithium acetylacetonate, are added to a reaction kettle, the amount of the basic catalyst is 5 ppm of lithium, the central metal atom, based on the weight of the final product; after replacing nitrogen, the temperature is raised to 190°C, the pressure is controlled at -0.05 Mpa, and the stirring rate is 150 rpm; after 3 hours of reaction, a prepolymer is obtained; after esterification is completed, a polycondensation reaction is carried out, which is divided into two stages of low vacuum and high vacuum; in the low vacuum stage, the vacuum degree is controlled at 1000 pa, the temperature in the kettle is controlled at 220°C, and the stirring rate is 100 rpm, and the residence time is 50 min; then, the high vacuum stage is entered, the vacuum degree is controlled at 80 pa, the temperature in the kettle is controlled at 220°C, and the stirring rate is 100 rpm, and the polycondensation reaction is carried out for 1 h, and then the product is discharged; then, it is drawn, cooled and cut into particles to obtain the low-color high-molecular-weight hydrogenated bisphenol A polycarbonate.

[0072] Experimental examples

[0073] The polycarbonates are prepared according to Examples 1-4 and Comparative Examples 1-4, respectively;

[0074] The properties of the obtained different polycarbonates are detected by the following detection methods:

[0075] Intrinsic viscosity: dichloromethane is used as the solvent to prepare a sample solution with a concentration of 0.05 mg / mL, the test temperature is 25°C, and the Ubbelohde viscometer is used for measurement.

[0076] Molecular weight (Mn): determined by gel permeation chromatography (GPC).

[0077] Yellowing index (YI): the light transmittance and yellowness of the hydrogenated bisphenol A polycarbonate are determined by an Agilent Ci7400 color difference meter.

[0078] Glass transition temperature (Tg): the glass transition temperature of the copolyester is tested by a TA Q100 differential scanning calorimeter, nitrogen is used as the test atmosphere, the heating rate is 10°C / min, the temperature is raised from 30°C to 300°C, then lowered to 30°C, and then raised to 300°C again.

[0079] Heat distortion temperature: a heat deflection temperature tester is used, silicone oil is used as the test heat transfer medium, the environmental conditions are a temperature of (25±2) °C and a relative humidity of (50±5) %, the temperature is raised at a speed of 120°C / h, the load is adjusted to 0.45 MPa, and the deflection temperature of the prepared polyester is tested.

[0080] Thermal gravimetric temperature: the decomposition temperature was tested by using Q-50 thermal gravimetric analyzer of TA company (America), nitrogen was used as the testing atmosphere, the sample mass was about 10 mg, the testing temperature was from room temperature to 600 ℃, and the temperature rising rate was 20 ℃ / min.

[0081] The molecular weight graph of the low chroma and high molecular weight hydrogenated bisphenol A polycarbonate prepared in Example 1 is shown in Figure 1. Figure 1

[0082] The testing results are shown in Table 1.

[0083] Table 1 testing results

[0084]

[0085] From Table 1, it can be seen that:

[0086] Compared with the comparative examples, the low chroma and high molecular weight hydrogenated bisphenol A polycarbonate prepared in the examples of the present application has better thermal denaturation temperature, glass transition temperature, molecular weight and viscosity, and lower chroma.

[0087] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the examples of the present application, and they should be covered in the scope of the claims and the specification of the present application.​

Claims

1. A process for the preparation of a low color, high molecular weight hydrogenated bisphenol A polycarbonate characterized in that, The preparation method comprises the following steps: (a) reacting hydrogenated bisphenol A with a sulfonylating agent in an organic base, a low-temperature environment and under stirring conditions, purifying to obtain a bis-sulfonate; (b) performing melt transesterification of the bis-sulfonate, diphenyl carbonate and an aliphatic diol under the condition of an alkaline catalyst, performing polycondensation after the reaction is completed, and then performing drawing, cooling and granulation on the reaction product to obtain the low-color high-molecular-weight hydrogenated bisphenol A polycarbonate.

2. The production method according to claim 1, characterized by, In the step (a), the sulfonylating agent is at least one selected from benzene sulfonyl chloride, methyl sulfonyl chloride, ethyl sulfonyl chloride, p-toluene sulfonyl chloride, 2-pyridine sulfonyl fluoride, chlorinated nonafluorobutyl sulfonyl, sulfonyl hydrazine and chlorosulfonyl isocyanate.

3. The preparation method according to claim 1, characterized in that, In the step (a), the molar ratio of the hydrogenated bisphenol A to the sulfonylating agent is 1:(2-4), and the molar ratio of the organic base to the sulfonylating agent is 1:(0.2-0.5). The organic base is at least one selected from triethylamine, pyridine and piperidine.

4. The method of claim 1, wherein, In the step (a), the low-temperature environment is 0-5℃, the stirring rate is 200-600 rpm, and the reaction time is 3-4 h.

5. The preparation method according to claim 1, characterized in that, In the step (b), the aliphatic diol is at least one selected from ethylene glycol, 1,4-cyclohexane dimethanol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol and 1,8-octanediol.

6. The method of claim 1, wherein, In the step (b), the alkaline catalyst is at least one selected from sodium methoxide, potassium methoxide, Lewis base catalyst, lithium chloride and lithium acetylacetonate.

7. The preparation method according to claim 1, characterized in that, In the step (b), the molar ratio of the sum of the bis-sulfonate and the aliphatic diol to the diphenyl carbonate is 1:(1-1.06); The molar ratio of the bis-sulfonate to the aliphatic diol is 1:(0.2-1).

8. The method of claim 1, wherein, In the step (b), the transesterification reaction conditions are as follows: the temperature is 180-200℃, the stirring rate is 100-200 rpm, the reaction time is 3-4 h, and the reaction pressure is -0.04 to -0.06 MPa; The polycondensation reaction conditions are as follows: the temperature is 210-230℃, the stirring rate is 50-150 rpm, the reaction time is 1-3 h, and the reaction pressure is 0.1-1100 pa.

9. The method of claim 1, wherein, In the step (b), the alkaline catalyst is added in an amount of 2-10 ppm of the central metal atom with respect to the final product.

10. The low-color high-molecular-weight hydrogenated bisphenol A polycarbonate prepared by the preparation method in any one of claims 1-9.

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