A polycarbonate copolymer, and a method of preparing and use thereof

Abstract

The present invention provides a polycarbonate copolymer having a high Vicat temperature and a method for producing the same. The polycarbonate copolymer of the present invention is characterized in that it contains structural units represented by formula (I) and structural units represented by formula (II), and satisfies formula (NK), S1 ≥ 48 (NK), wherein S1 represents the average mass content of the structural units represented by formula (II) in the polycarbonate copolymer having a weight average molecular weight of 28,000 or more and 50,000 or less obtained by separating the polycarbonate copolymer by gel chromatography. The polycarbonate copolymer has a high Vicat temperature and improved impact strength.

Description

Technical Field

[0001] This invention belongs to the field of polycarbonate, and specifically relates to a polycarbonate copolymer and its preparation method. Background Technology

[0002] Polycarbonate (PC) is the only transparent material among the five major engineering plastics. It has excellent mechanical properties, flame retardancy, weather resistance and electrical insulation properties, and is widely used in automobiles, electronic equipment, construction, office supplies, optical discs, sports equipment, medical care, computers, aerospace and other fields.

[0003] Copolycarbonate with a 1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane structure retains the excellent properties of polycarbonate while having a higher Vicat transition temperature. It can be used in fields with special requirements for transparency and heat resistance, such as automotive lights, LED lenses, and medical devices. However, due to the introduction of the 3,3,5-trimethylcyclohexane structure, its impact performance is significantly reduced compared to conventional bisphenol A type polycarbonate, exhibiting brittleness and a cantilever beam impact performance of <50J / m.

[0004] Therefore, it is essential to maintain high impact strength while improving the heat resistance of bisphenol A polycarbonate. Summary of the Invention

[0005] In view of the above-mentioned problems in the prior art, the purpose of this invention is to provide a polycarbonate copolymer with high Vicat temperature and high impact performance, and a method for preparing the same, which can improve the quality of polycarbonate with high heat distortion temperature and broaden its application fields.

[0006] The inventors discovered that by controlling the mass content of bisphenol TMC-derived polycarbonate structures within a certain range of weight-average molecular weight, and simultaneously controlling the ratio of weight-average molecular weight to Z-average molecular weight within a certain range, polycarbonate copolymers with both high Vicat temperature and high impact strength can be obtained.

[0007] Based on the above findings, in order to achieve the above requirements, the technical solution of the present invention is as follows:

[0008] A polycarbonate copolymer comprising structural units shown in formulas (I) and (II), and satisfying formula (NK),

[0009]

[0010] S1≥48 (NK)

[0011] In the formula, S1 refers to the average mass content of the structural unit shown in formula (II) in the polycarbonate copolymer obtained by gel chromatography with a weight average molecular weight of more than 28,000 and less than 50,000.

[0012] Furthermore, the polycarbonate copolymer satisfies formula (SM).

[0013] 1.1≤SM≤Equation 1.7 (SM)

[0014] SM is the ratio of the weight-average molecular weight to the Z-average molecular weight of the polycarbonate copolymer, determined by gel permeation chromatography.

[0015] In one embodiment of the present invention, the polycarbonate copolymer satisfies the following formula (NK a )

[0016] S1≥S2≥36 (NK) a )

[0017] In the formula, S2 refers to the average mass content of the structural unit shown in formula (II) in the polycarbonate copolymer obtained by gel chromatography with a weight average molecular weight of 15,000 or more and 28,000 or less.

[0018] In one embodiment of the present invention, the following formula (NK) is satisfied. b )

[0019] S2≥S3≥25 (NK) b )

[0020] In the formula, S3 refers to the average mass content of the structural unit shown in formula (II) in the polycarbonate copolymer obtained by gel chromatography with a weight average molecular weight of 5000 or more and 15000 or less.

[0021] In one embodiment of the invention, the polycarbonate copolymer satisfies the following formula (NK1).

[0022] S1 / SA>1 formula (NK1)

[0023] In the formula, SA represents the average mass content of the structural unit shown in formula (II) in the polycarbonate copolymer, %.

[0024] In one embodiment of the present invention, the polycarbonate copolymer has a Vicat temperature of ≥180°C and a cantilever beam impact strength of ≥200 J / m.

[0025] The present invention also relates to a method for preparing the above-mentioned polycarbonate copolymer.

[0026] In one embodiment of the present invention, the preparation method involves using bisphenol A and bisphenol TMC as monomers, and preparing them via phosgene interfacial polycondensation. The synthesis includes the following steps:

[0027] (1) Prepolymerization: Bisphenol A and bisphenol TMC are dissolved in sodium hydroxide aqueous solution for later use. A certain amount of the dissolved bisphenol A alkaline aqueous solution and bisphenol TMC alkaline aqueous solution are added to the reactor, and a certain amount of phosgene and dichloromethane are added to them. Preferably, the reaction temperature is 25-35℃ and the reaction time is 10-60 min, and the reaction yields a prepolymer;

[0028] (2) Post-condensation reaction: The prepolymer prepared in step (1) is transferred to the condensation reactor, and a certain amount of catalyst, end-capping agent and a certain amount of sodium hydroxide aqueous solution are added at the same time to maintain the pH of the reaction system > 11. Preferably, the reaction temperature is 30-35℃ and the reaction time is 2-4h to obtain the polymer liquid.

[0029] (3) Post-processing: The polymer solution obtained in step (2) is subjected to oil-water separation, followed by washing, devolatilization, pulverization and drying to obtain powder.

[0030] In one embodiment of the present invention, during the prepolymerization stage, preferably, the amount of dichloromethane is 1.8-2.2 times the mass of pure water.

[0031] In one embodiment of the present invention, during the prepolymerization stage, the bisphenol TMC alkaline aqueous solution is added in batches, preferably 2-5 times, more preferably 3-4 times.

[0032] In one embodiment of the present invention, in the prepolymerization, the molar ratio of the first added bisphenol A to bisphenol TMC is 1:(0.2-0.4), preferably 1:(0.25-0.3).

[0033] In one embodiment of the present invention, during prepolymerization, the number of times phosgene is added is the same as the number of times bisphenol TMC is added.

[0034] In one embodiment of the present invention, the total amount of phosgene added is 1.05-1.3 times, preferably 1.1-1.15 times, the total molar amount of bisphenol A and bisphenol TMC. Preferably, the initial amount of phosgene added is 1.05-1.3 times, preferably 1.1-1.15 times, the initial molar amount of bisphenol A and bisphenol TMC added, and the remaining phosgene is added in batches (preferably in equal amounts) together with bisphenol TMC.

[0035] In one embodiment of the present invention, the catalyst in the post-condensation polycondensation is triethylamine, and the amount added is preferably 0.3%-0.35% of the total molar amount of bisphenol A and bisphenol TMC; the end-capping agent is p-tert-butylphenol.

[0036] The beneficial effects of this invention are as follows:

[0037] This invention obtains a polycarbonate copolymer with both high Vicat temperature and high impact strength by controlling the mass content of bisphenol TMC-derived polycarbonate structures within a certain range of weight-average molecular weight, while also controlling the weight-average molecular weight and the ratio of weight-average molecular weight within a certain range. The polycarbonate copolymer has a Vicat temperature of ≥180℃ and a cantilever beam impact strength of ≥200J / m. Detailed Implementation

[0038] To better understand the technical solution of the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0039] The main analytical and evaluation methods used in the embodiments and comparative examples of this invention are as follows:

[0040] Molecular weight was determined by gel permeation chromatography (GPC) using a Waters 1515 gel permeation chromatograph with dichloromethane as the mobile phase and a temperature of 30°C.

[0041] Nuclear magnetic resonance (NMR) tests were performed using a Burker AVIII HD 400MHz NMR spectrometer.

[0042] The impact performance of the cantilever beam was determined according to the standard test method for testing the impact performance of plastic cantilever beams as specified in ASTM D256-1997.

[0043] The Vicat temperature was determined according to the Vicat temperature test method for plastics specified in ISO 306.

[0044] In the embodiments and comparative examples of this invention, all raw materials were ordinary reagents purchased from commercially available channels such as Aladdin Reagent Network.

[0045]

[0046] Example 1

[0047] The steps for preparing a polycarbonate copolymer with a high Vicat temperature are as follows:

[0048] (1) 14250g of 16wt% bisphenol A alkaline aqueous solution, 4030g of 20wt% bisphenol TMC alkaline aqueous solution and 32706g of dichloromethane were added to the reactor and stirred into a uniform emulsion. 1372.7g of phosgene was added to the emulsion and the temperature was 30℃ to start the reaction. After 20min of reaction, 1860g of 20wt% bisphenol TMC alkaline aqueous solution and 130.4g of phosgene were added to the reaction again and the reaction was continued for 10min. Then, 1860g of 20wt% bisphenol TMC alkaline aqueous solution and 130.4g of phosgene were added to the reactor and the reaction was continued for 20min to complete the prepolymerization.

[0049] (2) Transfer the prepolymerized product to the final polymerization reaction, add 151.5g of 3wt% triethylamine solution and 203.57g of 10wt% p-tert-butylphenol solution, and add 32wt% sodium hydroxide aqueous solution at the same time. Maintain the pH of the system at about 12.3 and the temperature at 32℃. React for 2.5h to complete the final polymerization.

[0050] (3) The product after final polymerization was washed with 20wt% NaOH solution, acid washed with 0.5mol / L hydrochloric acid, washed with deionized water, devolatilized (boiled in water in a glass kettle at 40℃ for 2h), pulverized, and dried (dried in a forced-air oven at 120℃ for 4h) to obtain polycarbonate copolymer.

[0051] Example 2

[0052] (1) 14250g of 16wt% bisphenol A alkaline aqueous solution, 4650g of 20wt% bisphenol TMC alkaline aqueous solution and 33000g of dichloromethane were added to the reactor and stirred into a uniform emulsion. 1480.1g of phosgene was added to the emulsion and the temperature was 25℃ to start the reaction. After 5min of reaction, 1250g of 20wt% bisphenol TMC alkaline aqueous solution and 95g of phosgene were added to the reaction again. After 10min of reaction, 1250g of 20wt% bisphenol TMC alkaline aqueous solution and 95g of phosgene were added to the reactor. After 20min of reaction, 1375g of 20wt% bisphenol TMC alkaline aqueous solution and 94.6g of phosgene were added. After 20min of reaction, the prepolymerization was completed.

[0053] (2) Transfer the prepolymerized product to the final polymerization reaction, add 156.55g of 3wt% triethylamine solution and 203.57g of 10wt% p-tert-butylphenol solution, and add 32wt% sodium hydroxide aqueous solution at the same time. Maintain the pH of the system at about 12.3 and the temperature at 33℃. React for 3h to complete the final polymerization.

[0054] (3) The product after final polymerization was washed with 20wt% NaOH solution, acid washed with 0.5mol / L hydrochloric acid, washed with deionized water, devolatilized (boiled in water in a glass kettle at 40℃ for 2h), pulverized, and dried (dried in a forced-air oven at 120℃ for 4h) to obtain polycarbonate copolymer.

[0055] Example 3

[0056] (1) 14250g of 16wt% bisphenol A alkaline aqueous solution, 6200g of 20wt% bisphenol TMC alkaline aqueous solution and 33500g of dichloromethane were added to the reactor and stirred into a uniform emulsion. 1524.6g of phosgene was added to the emulsion and the reaction was started at 26℃. After 10min of reaction, 2480g of 20wt% bisphenol TMC alkaline aqueous solution and 97.1g of phosgene were added to the reactor again and the reaction was continued for 10min to complete the prepolymerization.

[0057] (2) Transfer the prepolymerized product to the final polymerization reaction, add 157.56g of 3wt% triethylamine solution and 203.57g of 10wt% p-tert-butylphenol solution, and add 32wt% sodium hydroxide aqueous solution at the same time. Maintain the pH value of the system at about 12.3 and the temperature at 31℃. React for 3.5h to complete the final polymerization.

[0058] (3) The product after final polymerization was washed with 20wt% NaOH solution, acid washed with 0.5mol / L hydrochloric acid, washed with deionized water, devolatilized (boiled in water in a glass kettle at 40℃ for 2h), pulverized, and dried (dried in a forced-air oven at 120℃ for 4h) to obtain polycarbonate copolymer.

[0059] Example 4

[0060] (1) 14250g of 16wt% bisphenol A alkaline aqueous solution, 3100g of 20wt% bisphenol TMC alkaline aqueous solution, and 38500g of dichloromethane were added to a reactor and stirred to form a uniform emulsion. 1544.4g of phosgene was added to the emulsion, and the reaction was initiated at 35℃ for 10 min. 1472.5g of 20wt% bisphenol TMC alkaline aqueous solution and 122.25g of phosgene were added to the reactor again, and the reaction was continued for 10 min. This operation was repeated 3 times (i.e., a total of 5 additions of bisphenol TMC and phosgene), and the reaction was continued for 10 min to complete the prepolymerization.

[0061] (2) Transfer the prepolymerized product to the final polymerization reaction, add 157.56g of 3wt% triethylamine solution and 203.57g of 10wt% p-tert-butylphenol solution, and add 32wt% sodium hydroxide aqueous solution at the same time. Maintain the pH value of the system at about 12.3 and the temperature at 35℃. React for 4h to complete the final polymerization.

[0062] (3) The product after final polymerization was washed with 20wt% NaOH solution, acid washed with 0.5mol / L hydrochloric acid, washed with deionized water, devolatilized (boiled in water in a glass kettle at 40℃ for 2h), pulverized, and dried (dried in a forced-air oven at 120℃ for 4h) to obtain polycarbonate copolymer.

[0063] Example 5

[0064] (1) 14250g of 16wt% bisphenol A alkaline aqueous solution, 4340g of 20wt% bisphenol TMC alkaline aqueous solution, and 42702g of dichloromethane were added to a reactor and stirred to form a homogeneous emulsion. 1431.9g of phosgene was then added to the emulsion, and the reaction was initiated at 28℃. After 5 minutes, 4960g of 20wt% bisphenol TMC alkaline aqueous solution and 358g of phosgene were added back to the reactor, and the reaction was continued for another 5 minutes to complete the prepolymerization.

[0065] (2) Transfer the prepolymerized product to the final polymerization reaction, add 188.5g of 3wt% triethylamine solution and 203.57g of 10wt% p-tert-butylphenol solution, and add 32wt% sodium hydroxide aqueous solution at the same time. Maintain the pH value of the system at about 12.3 and the temperature at 30℃. React for 2 hours to complete the final polymerization.

[0066] (3) The product after final polymerization was washed with 20wt% NaOH solution, acid washed with 0.5mol / L hydrochloric acid, washed with deionized water, devolatilized (boiled in water in a glass kettle at 40℃ for 2h), pulverized, and dried (dried in a forced-air oven at 120℃ for 4h) to obtain polycarbonate copolymer.

[0067] Example 6

[0068] (1) 14250g of 16wt% bisphenol A alkaline aqueous solution, 6200g of 20wt% bisphenol TMC alkaline aqueous solution and 33560g of dichloromethane were added to the reactor and stirred into a uniform emulsion. 1930.5g of phosgene was added to the emulsion and the temperature was 30℃ to start the reaction. After 20min of reaction, 775g of 20wt% bisphenol TMC alkaline aqueous solution and 64.35g of phosgene were added to the reactor again. After 10min of reaction, 775g of 20wt% bisphenol TMC alkaline aqueous solution and 64.35g of phosgene were added to the reactor again. After 10min of reaction, the prepolymerization was completed.

[0069] (2) Transfer the prepolymerized product to the final polymerization reaction, add 176.8g of 3wt% triethylamine solution and 203.57g of 10wt% p-tert-butylphenol solution, and add 32wt% sodium hydroxide aqueous solution at the same time. Maintain the pH of the system at about 12.3 and the temperature at 32℃. React for 2.1h to complete the final polymerization.

[0070] (3) The product after final polymerization was washed with 20wt% NaOH solution, acid washed with 0.5mol / L hydrochloric acid, washed with deionized water, devolatilized (boiled in water in a glass kettle at 40℃ for 2h), pulverized, and dried (dried in a forced-air oven at 120℃ for 4h) to obtain polycarbonate copolymer.

[0071] Comparative Example 1

[0072] The difference between this comparative example and Example 1 is that in step (1), 7750g of bisphenol TMC alkaline aqueous solution and 1633.5g of phosgene were added at once, and the reaction was carried out at 25°C for 55 minutes.

[0073] Comparative Example 2

[0074] Purchased from commercially available APEC18XX products.

[0075] The performance test results of the polycarbonates prepared in the above embodiments and comparative examples are shown in Table 1 below:

[0076] Table 1

[0077]

[0078] The data comparison above shows that the polycarbonate copolymer of the present invention has high Vicat temperature and impact strength.

[0079] Those skilled in the art will understand that modifications or adjustments can be made to the present invention based on the teachings of this specification. These modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A polycarbonate copolymer, characterized in that, It includes the structural units shown in Equations (I) and (II), and satisfies Equations (NK), (SM), and (NK). a ), style (NK) b ), formula (NK1), Equation (I) Equation (II) S1≥48(NK) In the formula, S1 refers to the average mass content of the structural unit shown in formula (II) in the polycarbonate copolymer obtained by gel chromatography with a weight average molecular weight of more than 28,000 and less than 50,000, expressed as % %. 1.1≤SM≤1.7 (SM) SM is the ratio of the weight-average molecular weight to the Z-average molecular weight of the polycarbonate copolymer, as determined by gel permeation chromatography. S1≥S2≥36(NK a ) In the formula, S2 refers to the average mass content of the structural unit shown in formula (II) in the polycarbonate copolymer obtained by gel chromatography with a weight average molecular weight of more than 15,000 and less than 28,000, expressed as % %. S2≥S3≥25(NK b ) In the formula, S3 refers to the average mass content of the structural unit shown in formula (II) in the polycarbonate copolymer obtained by gel chromatography with a weight average molecular weight of 5000 or more and 15000 or less, representing % of the total mass content. S1 / SA>1(NK1) In the formula, SA represents the average mass content of the structural unit shown in formula (II) in the polycarbonate copolymer.

2. The polycarbonate copolymer according to claim 1, having a Vicat temperature of ≥180°C.

3. The polycarbonate copolymer according to any one of claims 1-2, having a cantilever beam impact strength of ≥200 J / m.

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