Method for determining total chlorine and inorganic chlorine content in polycarbonate resin

Abstract

The present application relates to a kind of determination methods of total chlorine and inorganic chlorine content in polycarbonate resin.In total chlorine content determination, the present application uses a certain concentration of metal hydroxide and carbonate mixed solution to carry out sufficient hydrolysis to the polycarbonate resin to be measured under certain temperature and pressure, and convert various forms of chlorine into sodium chloride for total chlorine detection.In the determination of inorganic chlorine content, the present application fully dissolves inorganic chlorine in polycarbonate by the method of water phase reverse phase extraction and organic phase liquid-liquid extraction.The above detection method converts the measured substance into the detection of chloride ion content in aqueous solution, which can be easily realized by spectroscopy or ion chromatography method, with the advantages of simple operation, good repeatability, high accuracy, etc., and can be used for the determination of chlorine content in polycarbonate product produced by interfacial polycondensation method and production process control.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of determination of chlorine content in polycarbonate, and particularly relates to a method for determining total chlorine content in polycarbonate resin and a method for determining inorganic chlorine content. BACKGROUND

[0002] The information disclosed in this Background section is only for the purpose of increasing the understanding of the general background of the application and does not necessarily constitute an admission or a recognition that the information forms part of the prior art that is already known in any country in the world.

[0003] In the interfacial reaction process of polycarbonate, a carbonyl source such as phosgene often reacts with sodium salt of bisphenol A (BPA) to generate polycarbonate by phosgenation, and by-product sodium chloride (NaCl) is generated. In this case, sodium chloride as a by-product of the reaction is dissolved in the aqueous solution light phase and can be removed by washing. Hydrolysis may occur during the removal of the solvent in the polymerization mother liquor to form hydrogen chloride or residual dichloromethane. If these impurities remain in the polycarbonate, yellowing of the polycarbonate resin will occur during the later processing, which limits the application of polycarbonate. In order to produce low-chlorine polycarbonate and improve the appearance quality of the product, the residual amount of chlorine in the production process and the end product should be monitored and controlled.

[0004] There is no report on the determination method of total chlorine in polycarbonate resin in the prior art. Although inorganic chlorine has been reported, there are many deficiencies. For example, a method for determining the chlorine ion content in polycarbonate is disclosed in patent PCT / IB2016 / 054177, polycarbonate is dissolved in a non-chlorinated solvent, then added to boiling water, polycarbonate is precipitated, non-chlorinated solvent is volatilized, and ion chromatography is used to determine the chlorine ion. The deficiency is that the non-chlorinated solvent cannot be completely removed in boiling water, and a large amount of water carries part of the chlorine to evaporate, resulting in large deviation of the test results. SUMMARY

[0005] Based on the above technical background, the present application aims to provide a method for determining the total chlorine content and the inorganic chlorine content in polycarbonate. After determination, the above two determination methods provided by the present application are simple to operate and have high accuracy.

[0006] In the first aspect of the present application, a method for determining the total chlorine content in polycarbonate resin is provided, and the determination method is characterized in that the polycarbonate resin sample to be measured is added to a mixed solution of hydroxide and carbonate, and hydrolysis is carried out at a certain temperature and pressure, and the chlorine element content in the hydrolyzed solution is determined.

[0007] In the above detection method, under certain temperature and pressure, polycarbonate resin is completely hydrolyzed into soluble salts such as sodium bisphenol A and sodium carbonate through hydrolysis with hydroxide and carbonate. Dichloromethane and terminal chloroformates in the resin are converted into sodium chloride. That is, the first aspect of this invention first converts the polycarbonate resin polymer into soluble salt molecules through hydrolysis, and the organic chlorine components in the sample are converted into inorganic sodium chloride for determination. The advantages of this determination method include at least the following aspects:

[0008] (1) In the above detection method, the polycarbonate resin undergoes a complete hydrolysis reaction under the conditions specified in this invention, the resin material is completely degraded and converted into water-soluble substances, and the chlorine-containing substances in the resin can be fully converted into sodium chloride in the aqueous solution. This can effectively ensure the accuracy and stability of the detection method of this invention.

[0009] (2) In the above detection method, polycarbonate resin is used to pretreat the sample before chlorine content determination by hydrolysis, which avoids the defects of inaccurate chlorine content determination results and low results in traditional methods such as high temperature digestion or direct leaching.

[0010] (3) The above detection method converts organic chlorine into sodium chloride as the analyte. Sodium chloride is readily available and cost-effective, which means that the quantitative standard of the above detection method is very easy to obtain, which can effectively reduce the reagent cost of enterprises in the product testing process. In addition, sodium chloride has good solubility and stability in water. The sodium chloride generated after hydrolysis is completely dissolved in the reaction system, and no other purification or extraction separation steps are required, which reduces the possibility of systematic error.

[0011] (4) The reagents involved in the above hydrolysis reaction are readily available and have high safety. The conditions of the hydrolysis reaction are also relatively mild, and the harm to operators is low.

[0012] The above detection method requires determining the chlorine content in the hydrolyzed solution. This determination can be performed using spectroscopy or ion spectroscopy. In one embodiment of the present invention, the detection method is spectral detection, specifically, single-wavelength X-ray fluorescence spectroscopy is used for detection.

[0013] In a second aspect, the present invention provides a method for determining the inorganic chlorine content in polycarbonate resin. The method is characterized in that the polycarbonate resin sample to be tested is added to a first non-chlorine solvent and shaken to dissolve. Then, water is added to the first non-chlorine solvent to fully dissolve the inorganic chlorine, and a mixed solution of the non-chlorine solvent and water is obtained. A second non-chlorine solvent is added to the mixed solution for extraction to obtain a lower aqueous phase, and the inorganic chlorine content in the aqueous phase is determined.

[0014] In the above determination method, the first non-chlorine solvent is soluble in water and the second non-chlorine solvent, and has better solubility in the second non-chlorine solvent; the second non-chlorine solvent is immiscible with water. In the second aspect of the present application, the polycarbonate resin is dissolved in the first non-chlorine solvent by using the above design, and the polycarbonate resin is precipitated from the solvent by using the difference in solubility of the polycarbonate resin and inorganic chlorine in water, and the inorganic chlorine is dissolved in the mixed solution of water and the first non-chlorine solvent, and then the first non-chlorine solvent miscible with water is extracted by using another second non-chlorine solvent immiscible with water, and the inorganic chlorine is dissolved in water, which can be detected by spectroscopy or ion spectrum method.

[0015] The beneficial effects of one or more of the above technical solutions are:

[0016] 1. Dichloromethane, chloroformate end groups, hydrogen chloride or sodium chloride and other forms of chlorine-containing compounds may exist in the interfacial polycondensation method polycarbonate, the present application uses alkali catalysis, heating and pressurization method to convert the insoluble polycarbonate resin into soluble material, and at the same time, various forms of chlorine are converted into sodium chloride, and the total chlorine is detected by single-wavelength X-ray fluorescence spectroscopy, which has not been reported at home and abroad.

[0017] 2. The present application dissolves the inorganic chlorine in the polycarbonate by using the method of aqueous phase back extraction and organic phase liquid-liquid extraction, which is accurate and reliable, and has not been reported at home and abroad.

[0018] 3. The method has the advantages of strong operability, simple operation, good repeatability, high accuracy, and is suitable for the determination of chlorine content in similar substances. BRIEF DESCRIPTION OF DRAWINGS

[0019] The drawings constituting a part of the specification of the present application are used to provide a further understanding of the present application, and the illustrative embodiments of the present application and their descriptions are used to explain the present application, and do not constitute an improper limitation on the present application.

[0020] Figure 1 The standard curve graph for determining the total chlorine content by the single-wavelength X-ray fluorescence spectroscopy method described in Example 1.

[0021] Figure 2 The chromatogram for determining the inorganic chlorine by the ion chromatography method in Example 8.

[0022] Figure 3 The standard curve graph for determining the inorganic chlorine content by the ion chromatography method in Example 8.

[0023] Figure 4 The standard curve graph for determining the inorganic chlorine content by the single-wavelength X-ray fluorescence spectroscopy method in Example 8. DETAILED DESCRIPTION

[0024] It should be noted that the following detailed description is illustrative only, and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0025] It is also important to note that the terms used herein are not intended to limit the particular embodiments of the present application which can be practiced with the examples disclosed. As used herein, unless expressly stated to the contrary, all

[0026] In a first aspect of the present application, a method for determining the total chlorine content in a polycarbonate resin is provided, the method being characterized in that a sample of the polycarbonate resin to be tested is added to a mixed solution of a hydroxide and a carbonate, and hydrolysis is carried out at a certain temperature and pressure, and the chlorine content in the hydrolyzed solution is determined.

[0027] In the above scheme, the sample of the polycarbonate resin to be tested is a desolventized dry powder, a flake or a resin particle, which is processed into a powder form and added to the mixed solution. The powder has a particle size of 1 um to 1000 um, and is further preferably 1 um to 500 um. The flake or resin particle can be processed into a powder form by shearing or extruding, including but not limited to using an ultra-low temperature pulverizer or a grinder to pulverize, or shearing and pulverizing after cooling with liquid nitrogen.

[0028] Preferably, the hydroxide is one or two of sodium hydroxide, potassium hydroxide, barium hydroxide, lithium hydroxide, and is further preferably sodium hydroxide or potassium hydroxide.

[0029] Preferably, the carbonate is one of sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate.

[0030] Preferably, in the mixed solution, the mass percentage concentration of the hydroxide solution is 20% to 40%, and the mass percentage concentration of the carbonate solution is 2% to 8%.

[0031] Preferably, the amount of the hydroxide added is 6 to 16 times the mass of the polycarbonate resin, and is further preferably 7 to 13 times.

[0032] Preferably, the temperature of the hydrolysis reaction is 80°C to 230°C, and is further preferably 95°C to 200°C; the pressure of the hydrolysis reaction is 0.1 to 4 MPa, and is further preferably 0.1 to 3 MPa, and if necessary, the reaction is carried out under a closed condition.

[0033] Preferably, the method for determining the content of chlorine element is spectral or ion chromatography detection; further, the detection method is spectral detection, and in specific examples, single-wavelength X-ray fluorescence spectrometry is used for detection.

[0034] In an embodiment of the above preferred technical solution, the specific steps of the detection method are as follows:

[0035] (1) A series of sodium chloride standard solution with concentration gradient is configured, the count rate of the sodium chloride standard solution is determined by using a single-wavelength X-ray fluorescence spectrometer, a regression curve of count rate relative to the concentration of sodium chloride is obtained by taking the concentration of the standard solution as the abscissa and the count rate as the ordinate;

[0036] (2) The mixed solution of hydroxide and carbonate is used as a blank solution, the count rate of chlorine element in the blank solution is determined by using single-wavelength X-ray fluorescence spectrometry or ion chromatography, the concentration value C 0-a of chlorine element in the blank solution is obtained according to the standard curve, the count rate of chlorine element in the solution after hydrolysis is determined by using single-wavelength X-ray fluorescence spectrometry, the concentration value C i of chlorine element in the sample solution is obtained according to the standard curve, and the content of total chlorine in the polycarbonate is calculated according to the formula ω = (C i-a -C 0-a ) × V / m.

[0037] Wherein, ω represents the content of total chlorine in the polycarbonate sample to be measured; C i-a represents the concentration of chlorine element in the sample solution to be measured; C 0-a represents the concentration of chlorine element in the blank solution; V represents the volume of the sample solution to be measured; and m represents the mass of the polycarbonate sample to be measured.

[0038] In the second aspect of the present application, a method for determining the content of inorganic chlorine in a polycarbonate resin is provided, and the method is characterized in that a polycarbonate resin sample to be measured is added into a first non-chlorine solvent and shaken to dissolve, then water is added into the first non-chlorine solvent to fully dissolve the inorganic chlorine, and a mixed solution of non-chlorinated solvent and water is obtained by separation; a second non-chlorine solvent is added into the mixed solution for extraction, a lower aqueous phase is obtained, and the content of inorganic chlorine in the aqueous phase is determined.

[0039] It should be noted that the polycarbonate resin sample in the second aspect is the same as that in the first aspect, but the difference is that when the polycarbonate resin is in the form of powder, the material should be pre-formed by extrusion or processed into granular form.

[0040] Preferably, the first non-chlorine solvent is tetrahydrofuran, N,N-dimethylformamide or a combination thereof, and further preferably, the first non-chlorine solvent is a combination of tetrahydrofuran and N,N-dimethylformamide.

[0041] Preferably, the second non-chlorine solvent is one of cyclohexane, petroleum ether, ethyl acetate, benzene, toluene, n-butane, pentane, n-hexane, benzyl alcohol, cyclohexanone, but not limited to.

[0042] Preferably, the amount of water added is 0.1-2 times, further preferably 0.3-1.8 times, of the volume of the first non-chlorine solvent.

[0043] Preferably, the amount of the second non-chlorine solvent added is 0.5-5 times, further preferably 1-3 times, of the volume of the first non-chlorine solvent.

[0044] Preferably, the inorganic chlorine content is determined by spectroscopic detection or ion chromatography. In one specific embodiment, the inorganic chlorine content is determined by single-wavelength X-ray fluorescence spectroscopy or ion chromatography. In this embodiment, the detection step is as follows:

[0045] (1) Obtain sample solution: add the polycarbonate resin sample to be tested into the first non-chlorine solvent and shake to dissolve. Then add water to the first non-chlorine solvent to fully dissolve the inorganic chlorine, and separate to obtain a mixed solution of non-chlorinated solvent and water. Add the second non-chlorine solvent to the mixed solution for extraction, and obtain the lower aqueous phase, which is the sample solution.

[0046] (2) Obtain blank solution: add the first non-chlorine solvent to water, and then add the second non-chlorine solvent for extraction. The amounts of the first non-chlorine solvent, water, and second non-chlorine solvent are the same as in step (1). Separate to obtain the aqueous phase as the blank solution.

[0047] (3) Obtain regression curve: configure a series of sodium chloride standard solution with gradient concentrations. Determine the count rate of the sodium chloride standard solution by single-wavelength X-ray fluorescence spectrometer, and obtain the regression curve of count rate versus sodium chloride concentration with the standard solution concentration as the horizontal coordinate and the count rate as the vertical coordinate. Determine the chlorine ion absorption peak area or peak height in the sodium chloride standard solution by ion chromatography, and plot the curve with the standard solution concentration as the horizontal coordinate and the chlorine ion absorption peak area or peak height as the vertical coordinate.

[0048] (4) Determine the inorganic chlorine content: determine the count rate of chlorine element or the chlorine ion absorption peak area or peak height in the blank solution by single-wavelength X-ray fluorescence spectroscopy or ion chromatography, and obtain the chlorine element concentration value C 0-b in the blank solution according to the standard curve.

[0049] Determine the count rate of chlorine element or the chlorine ion absorption peak area or peak height in the sample solution by single-wavelength X-ray fluorescence spectroscopy or ion chromatography, and obtain the chlorine element concentration value C i-b in the sample solution according to the standard curve, respectively. According to the formula ω = (C i-b -C 0-b) x V / m, the content of inorganic chlorine in the polycarbonate resin is calculated.

[0050] wherein ω represents the content of inorganic chlorine in the polycarbonate resin sample to be measured; C i represents the concentration of chlorine element in the sample solution to be measured; C0represents the concentration of chlorine element in the blank solution; V represents the volume of the sample solution to be measured; and m represents the mass of the polycarbonate resin sample to be measured.

[0051] In order for those skilled in the art to have a clearer understanding of the technical solutions of the present application, the technical solutions of the present application will be described in detail below in conjunction with specific examples.

[0052] Example 1

[0053] In this example, a method for determining the total chlorine content in a polycarbonate resin is provided, which comprises the following steps:

[0054] (1) Sample pretreatment: about 50 g of polycarbonate resin particles were crushed using a liquid nitrogen ultra-low temperature crusher, and the average particle size of the powder was 82 um. 6.5024 g, 6.2216 g, and 6.7186 g of polycarbonate powder were accurately weighed in a 150 mL reaction tank, respectively, and 53 g, 50 g, and 54 g of a mixed solution of potassium hydroxide (20 wt%) and sodium carbonate (5 wt%) were added, respectively. The mixture was heated to 180℃ under stirring, the pressure was 1.5 MPa, and the hydrolysis reaction was carried out for 8 h.

[0055] (2) Preparation of sample solution: the reaction liquid was cooled to room temperature, transferred to a 100 mL volumetric flask, diluted to the mark, and the resulting solution was used as the sample solution for three parallel samples.

[0056] (3) Preparation of blank solution: the same amount of mixed solution of potassium hydroxide (20 wt%) and sodium carbonate (5 wt%) was weighed according to step (1) and placed in three 100 mL volumetric flasks, respectively, and diluted to the mark to obtain the blank solution for three parallel samples.

[0057] (4) Preparation of sodium chloride standard solution: a sodium chloride standard solution with a concentration of 100 ug / mL was prepared, and deionized water was used to dilute and prepare sodium chloride standard solutions with concentrations of 2 ug / mL, 4 ug / mL, 6 ug / mL, 8 ug / mL, 10 ug / mL, and 13 ug / mL.

[0058] (5) Standard curve drawing: the chlorine element count rate of the six standard solutions was determined using a single-wavelength X-ray fluorescence spectrometer, and the standard curve was obtained by automatically processing the data by the instrument. The linear fitting equation obtained was Y = 0.2541X + 0.189, and the correlation coefficient r was 0.9998.

[0059] (6) Determination of the sample: The chlorine element count rate of the blank solution and the sample solution of three parallel samples was determined by using a single-wavelength X-ray fluorescence spectrometer, and the sodium chloride concentration in the three parallel sample solutions was calculated according to the linear fitting equation, respectively. The total chlorine content of the three polycarbonate resin parallel samples was calculated according to the formula ω = (C i-a -C 0-a ) × V / m.

[0060] Table 1

[0061]

[0062] Example 2

[0063] In this example, another determination method of the total chlorine content in the polycarbonate resin is provided, which comprises the following steps:

[0064] Accurately weigh 6.4812 g, 6.4089 g and 6.5126 g of the polycarbonate powder in Example 1, respectively, into a 150 mL reaction tank, add 45 g, 44 g and 46 g of the mixed solution of potassium hydroxide (30 wt%) and sodium carbonate (4 wt%) respectively, heat to 170℃ under stirring, the pressure is 2.1 MPa, and the hydrolysis reaction is 5 h.

[0065] After the reaction is completed, cool to room temperature, and determine the total chlorine content of the three polycarbonate resin parallel samples according to steps (2), (3), (4), (5) and (6) in Example 1.

[0066] Table 2

[0067]

[0068] Example 3

[0069] In this example, another determination method of the total chlorine content in the polycarbonate resin is provided, which comprises the following steps:

[0070] Accurately weigh 5.8612 g, 6.0365 g and 5.9862 g of the polycarbonate powder in Example 1, respectively, into a 150 mL reaction tank, add 41 g, 42 g and 42 g of the mixed solution of sodium hydroxide (30 wt%) and potassium carbonate (5 wt%) respectively, heat to 170℃ under stirring, the pressure is 1.8 MPa, and the hydrolysis reaction is 6 h.

[0071] After the reaction is completed, cool to room temperature, and determine the total chlorine content of the three polycarbonate resin parallel samples according to steps (2), (3), (4), (5) and (6) in Example 1.

[0072] Table 3

[0073]

[0074] Example 4

[0075] In this example, another method for determining the total chlorine content in a polycarbonate resin is provided, which comprises the following steps:

[0076] Sample pretreatment: 5.5024 g, 5.3325 g, and 5.4156 g of polycarbonate resin pellets were accurately weighed into a 150 mL reaction tank, respectively, and 45 g, 44 g, and 46 g of a mixed solution of potassium hydroxide (30 wt%) and sodium carbonate (5 wt%) were added, respectively. The mixture was heated to 100°C under stirring and hydrolyzed at normal pressure for 16 h.

[0077] After the reaction was completed, the mixture was cooled to room temperature, and the total chlorine content of the three polycarbonate resin samples was determined according to steps (2), (3), (4), (5), and (6) of Example 1.

[0078] Table 4

[0079]

[0080] Example 5

[0081] In this example, another method for determining the total chlorine content in a polycarbonate resin is provided, in which the pretreatment method is as follows:

[0082] Sample pretreatment: 4.3452 g, 5.0845 g, and 4.8352 g of polycarbonate resin pellets were accurately weighed into a 150 mL reaction tank, respectively, and 48 g, 56 g, and 53 g of a mixed solution of potassium hydroxide (10 wt%) and sodium carbonate (5 wt%) were added, respectively. The mixture was heated to 180°C under stirring and hydrolyzed at a pressure of 2 MPa for 16 h, and the polycarbonate hydrolysis rate was 52%.

[0083] Example 6

[0084] In this example, another method for determining the total chlorine content in a polycarbonate resin is provided, in which the pretreatment method is as follows:

[0085] Sample pretreatment: 6.5024 g, 6.3325 g, and 6.4156 g of polycarbonate resin pellets were accurately weighed into a 150 mL reaction tank, respectively, and 45 g, 44 g, and 46 g of a mixed solution of potassium hydroxide (35 wt%) and sodium carbonate (5 wt%) were added, respectively. The mixture was heated to 80°C under stirring and hydrolyzed at normal pressure for 16 h, and the polycarbonate hydrolysis rate was 86%.

[0086] Example 7

[0087] In this embodiment, another method for determining the total chlorine content in polycarbonate resin is provided, which adopts blank standard recovery determination, and the steps of the determination method are as follows:

[0088] (1) Preparation of sample: analytical pure sodium chloride is ground into fine powder by using a grinder. 2000 g of polycarbonate resin prepared by a non-phosgene method is placed in a high-speed mixer, 0.2 g of standard sodium chloride powder is added and mixed thoroughly, and then extrusion granulation and drying are performed.

[0089] (2) Pretreatment of sample: 50 g of extruded granules is crushed by using a liquid nitrogen cryogenic crusher, and the average particle size of the powder is 95 um. 5.0889 g, 5.0138 g, 5.1013 g and 5.0315 g of polycarbonate resin powder are weighed respectively, and hydrolysis reaction is performed according to the method of Example 1.

[0090] The total chlorine content in the four polycarbonate resin parallel samples is determined according to steps (2), (3), (4), (5) and (6) of Example 1, and the recovery rate of chlorine element is calculated.

[0091] Table 5

[0092]

[0093] In Examples 1-6 above, the same batch of polycarbonate resin sample is hydrolyzed by alkali and carbonate, and then repeated determination is performed. According to the results in Tables 1-4, it can be seen that the determination deviation of the total chlorine content in the polycarbonate resin is less than 0.1, which indicates that the above determination method has good repeatability. In Example 7, the chlorine recovery rate of the above sample treatment method is determined by adding sample recovery, and from the results in Table 5, it can be seen that the recovery rates of the four parallel samples of the same batch are not much different, and the average can reach 100.03%. The above data also prove that the detection method provided by the present application can fully extract and recover the chlorine element in the sample, and the method is stable and has high accuracy.

[0094] Example 8

[0095] In this embodiment, a method for determining the inorganic chlorine content in polycarbonate resin is provided, which comprises the following steps:

[0096] (1) Sample pretreatment

[0097] Accurately weigh 3.5121 g, 3.5093 g, 3.5109 g of polycarbonate resin particles into a 100 mL bottle with a stopper, respectively add 50 mL of tetrahydrofuran into the bottle, and then place the bottle in a shaker to completely dissolve. Accurately weigh 15 mL of deionized water, and slowly add it into the tetrahydrofuran solution under stirring. After the addition is completed, stir for 30 min. Transfer the mixture of tetrahydrofuran and water into a separatory funnel, and then add 100 mL of cyclohexane into the mixture. After shaking thoroughly, separate the lower layer of the aqueous phase.

[0098] (2) Preparation of sample solution

[0099] The separated aqueous phase is directly used as the sample solution for determination.

[0100] (3) Preparation of blank solution

[0101] Accurately weigh 50 mL of tetrahydrofuran into a 200 mL separatory funnel, and then accurately weigh 15 mL of deionized water into the tetrahydrofuran. After mixing, add 100 mL of cyclohexane, shake thoroughly, and then separate the lower layer of the aqueous phase. The obtained aqueous phase is used as the blank solution of the sample to be determined.

[0102] (4) Preparation of sodium chloride standard solution

[0103] The sodium chloride standard solution with a concentration of 100 ug / mL is diluted with water to prepare sodium chloride standard solutions with concentrations of 1 ug / mL, 2 ug / mL, 4 ug / mL, 6 ug / mL, 8 ug / mL, and 10 ug / mL.

[0104] (5) Preparation of standard curve:

[0105] ① The chloride element count rate of the six standard solutions is determined by using a single-wavelength X-ray fluorescence spectrometer. The count rate is used as the vertical coordinate, and the concentration is used as the horizontal coordinate. The standard curve is obtained by automatically processing the data by the instrument. The linear fitting equation is Y = 0.2622X + 0.163, and the correlation coefficient r = 0.9995.

[0106] ② The chloride ion absorption peak area of the six concentration gradient standard solutions is determined by using ion chromatography. The peak area is used as the vertical coordinate, and the chloride ion concentration (ug / mL) is used as the horizontal coordinate. The standard curve of the chloride ion absorption peak area and the concentration is obtained by automatically processing the data by the instrument. The linear fitting equation is Y = 1123800X - 34859, and the correlation coefficient r = 0.9998.

[0107] (6) Determination of sample:

[0108] ① The chloride element count rate of the blank solution and the three parallel sample solutions is determined by using a single-wavelength X-ray fluorescence spectrometer. The chloride ion concentration in the three parallel sample solutions is calculated according to the linear fitting equation. According to the formula ω = (Ci-b -C 0-b )×V / m to calculate the inorganic chlorine content of the three parallel samples.

[0109] 2. The ion chromatography was used to determine the chlorine element absorption peak area of the blank solution and the three parallel sample solutions, and the chlorine ion concentration of the sample to be measured was obtained according to the linear fitting equation of the standard curve. According to the formula ω = (C i-b -C 0-b )×V / m to calculate the inorganic chlorine content of the three parallel samples.

[0110] Table 6

[0111]

[0112] Table 7

[0113]

[0114] It can be seen from the results in Table 6 and Table 7 that the detection results by X-ray fluorescence spectrum are basically consistent with the detection results by ion chromatography, indicating that the above two detection methods can be applied to the inorganic chlorine determination method provided by the present application.

[0115] Example 9

[0116] In this embodiment, a determination method for the inorganic chlorine content in a polycarbonate resin is provided, and the determination method comprises the following steps:

[0117] (1) Sample pretreatment

[0118] 3.1078 g, 3.1231 g and 3.1099 g of polycarbonate resin particles were accurately weighed and placed in 100 mL bottles with stoppers, 40 mL of tetrahydrofuran was added respectively, and the mixture was completely dissolved in a shaker. 20 mL of deionized water was accurately measured and slowly added to the tetrahydrofuran solution under stirring, and after the addition was completed, the mixture was stirred for 30 min. The mixture of tetrahydrofuran and water was transferred to a separatory funnel, 90 mL of toluene was measured by a measuring cylinder and added to the mixture, and after being fully shaken, the lower water phase was taken after being static.

[0119] According to steps (2), (3), (4), (5) and (6) in Example 8, the ion chromatography was used to determine the inorganic chlorine content in the three parallel samples of polycarbonate resin.

[0120]

[0121]

[0122] Table 8

[0123] Example 10

[0124] In this embodiment, a method for determining the inorganic chlorine content in polycarbonate resin is provided, which comprises the following steps:

[0125] The test sample is polycarbonate resin powder generated in the production process, which is extruded into a strip at 300°C using a melt index tester, and then cut into particles. 3.5209 g, 3.5176 g and 3.5213 g of resin particles are accurately weighed into 100 mL bottles with stoppers, respectively, 50 mL of tetrahydrofuran is added into each bottle, and the mixture is completely dissolved in a shaker. 30 mL of deionized water is accurately measured and slowly added to the tetrahydrofuran solution under stirring, and the mixture is stirred for 30 min after the addition is completed. The mixture of tetrahydrofuran and water is transferred into a separatory funnel, 70 mL of toluene is measured by a measuring cylinder and added into the mixture, and the lower water phase is taken after shaking and standing.

[0126] The inorganic chlorine content in the three polycarbonate resin samples is determined according to steps (2), (3), (4), (5) and (6) of Example 8.

[0127] Table 9

[0128]

[0129] Example 11

[0130] In this embodiment, a method for determining the inorganic chlorine content in polycarbonate resin is provided, which comprises the following steps:

[0131] 5.0011 g, 5.0087 g and 5.0056 g of polycarbonate resin particles are accurately weighed into 200 mL bottles with stoppers, respectively, 50 mL of tetrahydrofuran is added into each bottle, and the mixture is completely dissolved in a shaker. 100 mL of deionized water is accurately measured and slowly added to the tetrahydrofuran solution under stirring, and the mixture is stirred for 30 min after the addition is completed. The mixture of tetrahydrofuran and water is transferred into a separatory funnel, 100 mL of toluene is measured by a measuring cylinder and added into the mixture, and the lower water phase is taken after shaking and standing.

[0132] The inorganic chlorine content in the three polycarbonate resin samples is determined according to steps (2), (3), (4), (5) and (6) of Example 9. Because the volume of water added is large, the chlorine content in the water after extraction is low, the signal response is weak, which leads to low results, poor stability, repeatability and accuracy.

[0133] Table 10

[0134]

[0135] Example 12

[0136] In the embodiment, a method for determining the inorganic chlorine content in polycarbonate resin is provided, and the method comprises the following steps:

[0137] The polycarbonate extruded particle sample of Example 7 was taken to determine the blank standard recovery. 2.0135 g, 2.0189 g, 2.0156 g and 2.0110 g of polycarbonate resin particles were accurately weighed and placed in 100 mL bottles with stoppers, and 25 mL of tetrahydrofuran was added to each bottle to completely dissolve in a shaker. 40 mL of deionized water was accurately measured and slowly added to the tetrahydrofuran solution under stirring, and the mixture was stirred for 30 min after the addition was completed. The mixture of tetrahydrofuran and water was transferred to a separatory funnel, 50 mL of toluene was measured by a measuring cylinder and added to the mixture, and the lower water phase was taken after shaking and standing.

[0138] The single-wavelength X-ray fluorescence spectrometer was used to determine the inorganic chlorine content in the four polycarbonate resin parallel samples according to the steps (2), (3), (4) and (5) of Example 8. The blank standard recovery rate was calculated by the ratio of the sample determination value to the theoretical value of 100 ug / g.

[0139] Table 11

[0140]

[0141] Similarly, the chlorine recovery rate of the sample processing method was determined by the sample recovery method in Example 12. As can be seen from the results in Table 11, the recovery rates of the four polycarbonate resin parallel samples of the same batch are basically the same, and the average can reach 99.87%, which confirms that the inorganic chlorine detection method provided by the present application also has good stability and accuracy.

[0142] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for determining the total chlorine content in polycarbonate resin, characterized in that, The method is characterized in that the polycarbonate resin sample to be tested is added to a mixed solution of hydroxide and carbonate under certain temperature and pressure to perform hydrolysis, and the chlorine content in the hydrolyzed solution is determined. Hydrolysis converts various forms of chlorine into sodium chloride; In the mixed solution, the hydroxide solution has a mass percentage concentration of 20% to 40%, and the carbonate solution has a mass percentage concentration of 2% to 8%. The amount of hydroxide added is 6 to 16 times the mass of the polycarbonate; The hydrolysis reaction is carried out at a temperature of 80℃~230℃; The hydrolysis reaction is carried out at a pressure of 0.1 MPa to 4 MPa, and may be conducted under closed conditions if necessary. The method for determining the chlorine content is single-wavelength X-ray fluorescence spectroscopy or ion chromatography.

2. The method for determining the total chlorine content in polycarbonate resin as described in claim 1, characterized in that, The polycarbonate resin sample to be tested is in the form of powder, flakes, or resin particles.

3. The method for determining the total chlorine content in polycarbonate resin as described in claim 2, characterized in that, Polycarbonate resin powder is used, and the particle size of the powder is 1µm to 1000µm.

4. The method for determining the total chlorine content in polycarbonate resin as described in claim 3, characterized in that, The powder has a particle size of 1µm to 500µm.

5. The method for determining the total chlorine content in polycarbonate resin as described in claim 1, characterized in that, The hydroxide is one or two of sodium hydroxide, potassium hydroxide, barium hydroxide, and lithium hydroxide.

6. The method for determining the total chlorine content in polycarbonate resin as described in claim 5, characterized in that, The hydroxide is sodium hydroxide or potassium hydroxide.

7. The method for determining the total chlorine content in polycarbonate resin as described in claim 1, characterized in that, The carbonate is one of sodium carbonate, sodium bicarbonate, potassium carbonate, or potassium bicarbonate.

8. The method for determining the total chlorine content in polycarbonate resin as described in claim 1, characterized in that, The amount of hydroxide added is 7 to 13 times the mass of the polycarbonate.

9. The method for determining the total chlorine content in polycarbonate resin as described in claim 1, characterized in that, The hydrolysis reaction is carried out at a temperature of 95℃ to 200℃.

10. The method for determining the total chlorine content in polycarbonate resin as described in claim 1, characterized in that, The hydrolysis reaction is carried out at a pressure of 0.1 MPa to 3 MPa.

11. The method for determining the total chlorine content in polycarbonate resin as described in claim 1, characterized in that, The specific steps of the detection method are as follows: (1) Prepare a series of sodium chloride standard solutions with different concentration gradients, and use a single-wavelength X-ray fluorescence spectrometer to determine the count rate of the sodium chloride standard solutions. Use the standard solution concentration as the abscissa and the count rate as the ordinate to obtain the regression curve of the count rate relative to the sodium chloride concentration. (2) Using the mixed solution of hydroxide and carbonate as a blank solution, the count rate of chlorine in the blank solution was determined by single-wavelength X-ray fluorescence spectrometry or ion chromatography. The concentration value C of chlorine in the blank solution was obtained according to the standard curve. 0-a The count rate of chlorine in the hydrolyzed solution was determined by single-wavelength X-ray fluorescence spectroscopy, and the concentration C of chlorine in the sample solution was obtained according to the standard curve.

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