JP2015200637A - Recovery solvent analysis method and unit, solvent recovery preparation method, and solvent film formation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recovery solvent analysis method and unit for determining a mass ratio of a plurality of solvent components contained in a recovery solvent while reducing the error, a solvent recovery preparation method, and a solvent film formation method.SOLUTION: An analysis unit 10 acquires a mass ratio of solvent components, for a recovery solvent to be a liquid mixture to be recovered. The analysis unit 10 includes a thermostatic chamber 13, a measuring device 14, a vaporization chamber 16, a separation part 17, a detector 18, and a ratio calculation part 19b. The measuring device 14 takes a sample to be vaporized in the vaporization chamber 16 from the recovery solvent. The thermostatic chamber 13 increases the temperature of the recovery solvent measured by the measuring device 14 by heating, and adjusts the temperature to a specific temperature.

Description

  The present invention relates to a recovery solvent analysis method and unit, a solvent recovery preparation method, and a solution casting method.

  A panel of a display device such as a liquid crystal display is used by laminating a plurality of polymer films. For example, a polarizing plate is used for a liquid crystal display, and the polarizing plate is composed of a polarizing film and protective films disposed on both sides of the polarizing film. An optical compensation film may be used as a protective film. Representative examples of protective films and optical compensation films include TAC films containing cellulose triacetate (hereinafter referred to as TAC) as a polymer component, and polarizing films include polyvinyl alcohol (hereinafter referred to as PVA) and modified PVA. There is a PVA film containing as a polymer component.

  The TAC film is produced by a solution casting method in which a TAC solution in which TAC is dissolved in a solvent is cast on a support, peeled off, and dried. Then, according to the intended quality and application, for example, a casting method such as single layer casting or co-casting is selected, and thereby a TAC film having a single layer structure or a multilayer structure is manufactured. The solvent of the TAC solution is a mixture in which compounds as a plurality of solvent components are mixed in consideration of the solubility of TAC and various conditions of the film forming process. For example, a mixture of dichloromethane and methanol There is. In the case of co-casting, a plurality of types of TAC solutions are used. Examples of the plurality of types of TAC solutions include those in which the mass ratios of the solvent components in the solvent that is a mixture are different from each other.

  Along with the improvement in the quality of the panel, an improvement in quality is also required for individual polymer films such as TAC films and laminated members such as polarizing plates on which polymer films are laminated. For example, for a polarizing plate, it has been required to improve the adhesion between the TAC film and the polarizing film so that the TAC film and the polarizing film are not easily peeled off. It has been found that this improvement in adhesion can be improved by co-casting a plurality of TAC solutions when a TAC film is produced by a solution casting method. Specifically, a surface layer forming a film surface to be in close contact with the polarizing film is formed on the film body by co-casting. Each solvent of the first TAC solution for forming the film main body and the second TAC solution for forming the surface layer is a mixture containing dichloromethane. The solvent for producing the second TAC solution is assumed to have a higher mass ratio of dichloromethane than the solvent for producing the first TAC solution. Thereby, the above-mentioned adhesion is improved. In this case, each solvent of the first TAC solution and the second TAC solution can be made independently. However, a solvent of the first TAC solution is prepared and used as a reference solvent, and dichloromethane is used as the reference solvent. It is preferable to prepare a solvent for the second TAC solution by adding. This is because there is a great advantage of securing a reference solvent that can be used in common to produce a plurality of types of films having different properties.

  In the production of a polymer film by a solution casting method, the solvent is recovered and reused. In the reuse, the solvent circulates between a film forming apparatus for manufacturing a film and a recovery preparation apparatus for preparing a solvent for recovering from the film forming apparatus and manufacturing a new dope. During the drying process in the film forming apparatus, the solvent evaporates to become a gas, and this gas is recovered and condensed to be a liquid. For this reason, when the solvent used for the production of the film is only the reference solvent, the mass ratio of the solvent component in the recovered solvent recovered is almost the same as the mass ratio of the solvent component in the reference solvent. However, when switching the film to be produced from the case where the solvent to be used is only the reference solvent to the case where the reference solvent and the solvent component having a mass ratio different from the reference solvent are switched, The mass ratio of the solvent component varies, and the mass ratio of the solvent component in the recovered solvent is different from that in the reference solvent. For example, in the case where the film is produced using only the first TAC solution described above, the solution casting process is switched from the case where the film is produced using the first TAC solution and the second TAC solution. As described above, when the reference solvent is prepared by changing the mass ratio of the solvent component or by reusing a recovered solvent having a different mass ratio from the reference solvent, the mass ratio of the solvent component in the reference solvent is set before use. Confirmation is required for quality control. And since this reference | standard solvent affects the property of many films, it must be managed by a strict reference | standard regarding quality, especially the mass ratio of a solvent component.

  By the way, gas chromatography (GC, Gas Chromatography) has been used as a method for purification, preparation, and quality control of liquids for a long time, and online gas chromatography that performs online analysis has also become widespread. For example, in the distillation of benzene and the distillation of a liquid mixture composed of a plurality of components, methods for analyzing benzene and mixtures using online gas chromatography have been proposed (see, for example, Patent Documents 1 and 2). In addition, a distillation column provided with an on-line gas chromatograph as a remotely operable analyzer has been proposed, and a method using a coalescer has also been proposed to reduce errors (see, for example, Patent Documents 3 and 4).

Japanese Patent Laid-Open No. 06-166640 Japanese Patent Laid-Open No. 07-178301 JP 2005-199188 A JP 2007-196171 A

  However, even if the mass ratio of the solvent component is determined for the reference solvent, the quality may not be constant. This is based on the fact that there is a large error in determining the mass ratio of the solvent component for the recovered solvent reused to prepare the reference solvent. Even if the method of Patent Document 4 is used, the error with respect to the recovered solvent is too large from the viewpoint of quality control of the reference solvent, and exceeds the allowable range in quality control.

  Accordingly, an object of the present invention is to provide a recovered solvent analysis method and unit, a solvent recovery preparation method, and a solution casting method for obtaining a mass ratio of solvent components with a reduced error for a recovered solvent that is a mixture.

  In order to solve the above problems, the recovery solvent analysis method of the present invention includes a temperature adjustment step for adjusting the recovery solvent recovered as a liquid mixture to a specific temperature by heating and maintaining the specific temperature. In this state, a sampling step for sampling a specific amount from the recovered solvent, a vaporization step for vaporizing the sample sampled in the sampling step by heating, and a sample vaporized in a column having a stationary phase are guided as a mobile phase. A separation step for separating each solvent component contained in the sample by passing through the column with a carrier gas, a detection step for detecting the amount of the separated solvent component, and a solvent based on each detected amount And a ratio calculating step for calculating a mass ratio of the components.

  When the boiling point of the recovered solvent is TL ° C, the specific temperature is preferably in the range of (TL-30) ° C or higher and lower than TL ° C.

  When calculating the mass ratio of the solvent component a plurality of times, the series of steps of the temperature adjustment step, the sampling step, the vaporization step, the separation step, the detection step, and the ratio calculation step are repeated, Preferably the temperatures are the same.

  The temperature adjustment step passes through a temperature-controlled tube having a tube for guiding the recovered solvent, a chamber for housing the tube and partitioning the space surrounding the tube and an external space, and a temperature control mechanism for controlling the internal temperature of the chamber. It is preferable to adjust the recovered solvent to a specific temperature.

  The recovery solvent analysis unit of the present invention comprises a temperature adjusting means for adjusting the recovered solvent recovered as a liquid mixture to a specific temperature by heating, and the temperature of the recovered solvent guided from the adjusting means to the specific temperature. A sampling unit that samples a specific amount from the recovered solvent, a vaporization means that vaporizes the sampled sample by heating, and a stationary phase that guides the vaporized sample are provided inside, and the sample is stationary. A column in which a carrier gas as a mobile phase for passing through the column is guided, a detector for detecting the amount of the solvent component separated by the column, and the amount of the solvent component based on each amount detected by the detection unit And a ratio calculation unit that calculates a mass ratio.

  The present invention recovers a solvent evaporated in a solution casting process for producing a film from a polymer solution obtained by dissolving a polymer in a solvent that is a mixture of a first solvent component and a second solvent component, and uses the recovered solvent as a recovery solvent. In the solvent recovery and preparation method for preparing a new solvent, the solvent evaporated in the solution casting process is collected in a gaseous state and condensed to form a liquid recovery solvent, and the recovered solvent is distilled. A first distillation step of removing impurities to form a distilled solvent that is a mixture of the first solvent component and the second solvent component, and dividing the distilled solvent into first to third distilled solvents, Among these, a temperature adjusting step of adjusting the first distilled solvent to a specific temperature by heating, and a sample that samples a specific amount from the first distilled solvent while maintaining the specific temperature A process, a vaporization process in which the sample sampled in the sampling process is vaporized by heating, a sample vaporized in the vaporization process is guided to a column having a stationary phase, and the sample is passed through the column by a carrier gas as a mobile phase A separation step for separating the first solvent component and the second solvent component contained in the sample, a detection step for detecting each amount of the first solvent component and the second solvent component separated in the separation step, and detection A ratio calculating step for calculating a mass ratio of the first solvent component and the second solvent component based on each amount detected in the step, and the first solvent component and the second solvent by distilling the second distilled solvent. The amount of addition of the first solvent component and the second solvent component is determined based on the mass ratio calculated in the second distillation step separated into the solvent component and the ratio calculation step, respectively. The 1st solvent which prepares the 1st new solvent for using for the subsequent solution film forming process by adding the 1st solvent ingredient and the 2nd solvent ingredient obtained by the distillation process to the 3rd distilled solvent By adding the first solvent component obtained in the second distillation step to a part separated from the preparation step and the first new solvent, the mass ratio of the first solvent component is higher than that of the first new solvent. And a second solvent preparation step for preparing a high second new solvent.

  The solution casting process includes a first polymer solution obtained by dissolving a polymer in a first solvent and a second polymer obtained by dissolving the polymer in a second solvent in which the mass ratio of the first solvent component is higher than that of the first solvent. This is particularly effective when a film having a multilayer structure is produced from a solution.

  The solution casting method of the present invention comprises preparing a first polymer solution by dissolving a polymer in the first new solvent obtained by the above solvent recovery preparation method, and dissolving the polymer in a second new solvent. A casting film is formed by continuously flowing out of a casting die to a casting support for moving the first polymer solution and the second polymer solution, and a polymer solution preparation step for preparing a second polymer solution. A casting process, and a drying process in which the casting film is continuously peeled off from the casting support and dried to form a film.

  According to the present invention, the mass ratio of the solvent component can be determined for the recovered solvent as a mixture while suppressing errors.

It is the schematic of the collection | recovery solvent analysis unit which implemented this invention. It is sectional drawing of the film obtained by implementing this invention. It is sectional drawing of a polarizing plate. It is the schematic of solution casting apparatus. It is the schematic of a solvent collection | recovery preparation apparatus.

  As shown in FIG. 1, a recovery solvent analysis unit (hereinafter referred to as an analysis unit) 10 is for analyzing a recovery solvent recovered from a solution casting apparatus 62 (see FIG. 4) described later. Specifically, the analysis unit 10 is for obtaining the mass ratio of a plurality of solvent components contained in the liquid recovery solvent as a mixture online, and as a solvent component in addition to the mass ratio of the solvent component These compounds are for identifying each of the compounds. In the present embodiment, the entire amount of the recovered solvent recovered from the solution casting apparatus 62 (see FIG. 4) is not supplied to the analysis unit 10, but as described later, for example, part of the recovered solvent that has been used in particular. Is provided to the analysis unit 10. Details of the solution casting apparatus will be described later with reference to another drawing. In this embodiment, since the solution casting apparatus 62 uses dichloromethane and methanol as the solvent components of the first solvent 68 and the second solvent 69 (see FIG. 4), the solvent components in the recovered solvent are dichloromethane and methanol. It is. However, each solvent component of the 1st solvent 68 and the 2nd solvent 69 is not limited to these, The 1st solvent 68 and the 2nd solvent 69 may consist of three or more solvent components. For example, the first solvent 68 and the second solvent 69 are each a three-component system composed of dichloromethane, methanol, and 1-butanol, or a four-component system composed of dichloromethane, methanol, 1-butanol, and a small amount of water. May be.

  The analysis unit 10 includes a quantification unit 15 including a temperature-controlled room 13 and a meter 14, a vaporization chamber 16, a separation unit 17, a detector 18, and a composition calculator 19. The configuration including the vaporization chamber 16, the separation unit 17, the detector 18, and an identification unit 19a described later of the composition calculator 19 is the same as that of a so-called online gas chromatograph. The quantification unit 15 is for sampling a specific amount supplied to the vaporization chamber 16 from the guided recovered solvent as a sample.

  The temperature-controlled room 13 is temperature adjusting means for adjusting the temperature of the recovered solvent to a specific temperature, and includes a tube 26, a chamber 27, and a first temperature control mechanism 28. In order to suppress evaporation, the recovered solvent is preferably guided to the temperature-controlled room 13 while being kept at a temperature as low as possible. In the present embodiment, the recovered solvent is guided to the temperature-controlled room 13 in a state where the temperature is kept at a low temperature in the range of 0 ° C. or higher and 40 ° C. or lower. Each end of the pipe 26 is disposed in an opening provided in the chamber 27, one end being an inlet to which the recovered solvent is supplied and the other end being an outlet from which the recovered solvent is discharged. This outlet is connected to the meter 14. The chamber 27 accommodates a pipe 26 that guides the recovered solvent, and partitions the space around the pipe 26 from the external space. The first temperature control mechanism 28 controls the temperature inside the chamber 27 by heating the inside of the chamber 27, and the temperature of the recovered solvent passing through the pipe 26 is raised by this control and higher than before being introduced into the pipe 26. Adjust to a specific temperature (temperature adjustment step). However, the specific temperature is a temperature at which the vaporization of the recovered solvent can be suppressed. The tube 26 is provided with a pressurizing mechanism (not shown), but this pressurizing mechanism is not necessarily provided. The pressurizing mechanism pressurizes the inside of the pipe 26, whereby the recovered solvent is guided in the pipe 26 in a pressurized state. Thus, when the recovered solvent is put under pressure in the pipe 26, the above-mentioned specific temperature may be set to a temperature at which vaporization is suppressed under pressure.

  The material of the pipe 26 is SUS316 which is stainless steel. However, it is not limited to SUS316, and any material may be used as long as it does not deteriorate due to contact with the recovered solvent under the specific temperature described above and does not alter the recovered solvent. Furthermore, the higher the heat transfer coefficient, the more preferable the material is because the length of the tube 26 can be shortened and the recovered solvent can be brought to a specific temperature in a short time. The length of the tube 26 in the chamber 27 is 35 m. However, it is not limited to 35 m, and may be changed according to the material, the wall thickness and diameter of the pipe 26, and the specific temperature described above.

  For example, a water tank or the like may be used instead of or in addition to the chamber 27. In the case of a water tank, the pipe 26 is placed in the water stored in the water tank, and the recovered solvent passing through the pipe 26 is heated to a specific temperature within a range that suppresses vaporization through the water whose temperature is adjusted. Adjust.

The measuring device 14 as a sampling unit measures and samples from the recovered solvent guided from the temperature-controlled room 13 (sampling process). Sampling measures a specific amount supplied to the vaporization chamber as described below. In this embodiment, the amount to be weighed is within the range of 0.33 to 1 microliter (0.33 × 10 ⁻⁹ m ³ to 1 × 10 ⁻⁹ m ³ ). For example, it is determined by the volume of the measuring tube, and is not limited to the above range. The first temperature control mechanism 28 is connected to the meter 14 in addition to the chamber 27, and maintains the recovered solvent to be metered at a specific temperature adjusted in the temperature-controlled room 13. That is, the first temperature control mechanism 28 maintains the temperature of the recovered solvent in the meter 14 at the temperature reached by the temperature increase in the temperature-controlled room 13.

  The vaporizing chamber 16 is for a vaporizing process in which the sample that has been weighed and guided by the measuring instrument 14 is vaporized by heating. Inside the vaporizing chamber 16, an accommodating portion (not shown) is arranged, and the vaporizing chamber 16 has a heating mechanism (not shown). The accommodating part is formed in a tubular shape, and allows the sample from the measuring instrument 14 to pass through. The heating mechanism heats the inside of the vaporizing chamber 16 so that the temperature of the housing portion becomes equal to or higher than the temperature at which the sample vaporizes. In the present embodiment, the inside of the vaporizing chamber 16 is heated to 85 ° C. or higher in order to heat the accommodating portion to 85 ° C.

  As in the present embodiment, the vaporization chamber 16 includes the above-described storage unit and heating mechanism, and the analysis unit 10 controls the heating mechanism of the vaporization chamber 16 in order to control the temperature inside the vaporization chamber 16. A temperature control mechanism 31 is preferably provided. The second temperature control mechanism 31 keeps the temperature in the vaporization chamber 16 constant by controlling the heating mechanism of the vaporization chamber 16. In this embodiment, the temperature in the vaporization chamber 16 is kept constant at 85 ° C., but is not limited to this temperature. In addition, it is preferable that all the electronic devices provided in the analysis unit 10 are placed in a constant temperature environment, and the temperature is preferably constant within a range of 10 ° C. or higher and 20 ° C. or lower. This temperature control may be performed by, for example, an air conditioner (not shown).

The separation unit 17 is for a separation step of separating a gaseous sample that is a mixture into contained solvent components, and includes a column 32, a temperature-controlled room 33, and a carrier gas supply unit 34. . If the recovered solvent contains a substance that was not contained in the first solvent 68 and the second solvent 69 (see FIG. 4), this substance is also separated. The column 32 is for allowing the sample to pass through the carrier gas 35 supplied as described later and separating it into each solvent component, and is composed of a column tube 32a and a stationary phase 32b. The column 32 is a so-called capillary column formed by applying a stationary phase 32b to the inner wall of the column tube 32a. The material of the column tube 32a is SUS. The stationary phase 32b holds each compound such as the first solvent component and the second solvent component contained in the sample for separation. The carrier gas supply unit 34 supplies a carrier gas 35 as a mobile phase to the column 32 at a constant flow rate. The carrier gas 35 may be selected according to the type of compound such as a solvent component to be separated and the stationary phase. For example, helium (He), nitrogen (N ₂ ), hydrogen (H ₂ ), or the like can be used, and H ₂ is used in this embodiment.

  The aforementioned second temperature control mechanism 31 is connected to the temperature-controlled room 33 in addition to the heating mechanism of the vaporization chamber 16. The second temperature control mechanism 31 keeps the temperature of the atmosphere inside the temperature-controlled room 33, that is, the atmosphere surrounding the column 32 constant, thereby adjusting the temperature of the stationary phase 32b and the sample passing through the column 32 via the column tube 32a. Control.

  The material of the column tube 32a may be glass instead of SUS. The stationary phase 32b may be selected according to the solvent component and the type of impurities contained in the sample. The column 32 of this embodiment is a capillary column as described above, but instead of this, a so-called packed column in which a stationary phase is packed in a column cylinder may be used. From the viewpoint of the number of separation stages per unit length, a capillary column is preferred. In FIG. 1, only one column 32 and one detector 18 are shown, but a plurality of columns 32 and a plurality of detectors 18 having different stationary phases 32b may be used. A plurality of columns 32 and detectors 18 are provided.

  The detector 18 is for a detection process for detecting the amount of the solvent component separated by the column 32. The detector 18 includes a sensor (not shown) that detects each solvent component in the order guided from the column 32 and outputs a detection signal. The signal level of the detection signal corresponds to the amount of the solvent component that has been guided per unit time, that is, the level increases as the amount per unit time increases. The detector 18 obtains the amount of the solvent component from the peak area obtained by integrating the detection signal for each solvent component detected by the sensor. The detector 18 sends the detection signal and the obtained amount of each solvent component to the composition calculator 19.

  The composition calculator 19 includes an identification unit 19a and a ratio calculation unit 19b. The identification unit 19a is for identifying each separated solvent component. The identification unit 19a measures the retention time (retention time) from the start of introduction of the sample into the column 32 to the peak of the detection signal for each solvent component detected by the detector 18, and the retention time. The compound as a solvent component detected based on the above is identified. In this identification, for example, the solvent component corresponding to the retention time is determined by comparing the retention time unique to each solvent component to be identified with a reference retention time measured in advance. The ratio calculation unit 19b calculates the mass ratio of the solvent component detected from the amount of each solvent component obtained by the detector 18 (ratio calculation step).

  In the present embodiment, the detector 18 detects the mass as the above-mentioned quantity, but a detector that detects the volume as the quantity can also be used. In this case, the mass ratio may be calculated by obtaining the mass from the detected volume, for example, by the ratio calculation unit 19b. When calculating | requiring mass from a volume, based on the kind of compound as a solvent component identified by the identification part 19a, mass is calculated | required from the temperature at the time of detection with a detector, a pressure, etc., for example. Further, this analysis unit 10 is used in a solvent recovery / preparation device 63 (see FIG. 5) described later, and the preparation calculator 112 (see FIG. 5) of the solvent recovery / preparation device 63 can determine the mass from the volume. In this case, a detector that detects the volume as a quantity may be used as the detector 18, and a detector that calculates the volume ratio may be used as the ratio calculator 19b.

  When the solvent component contained in the recovered solvent and the order of the solvent component guided from the column 32 to the detector 18 are known in advance, the identification unit 19a is unnecessary, and therefore the composition calculator 19 is used instead. The ratio calculating unit 19b may be used.

  The operation of the above configuration will be described. The recovered solvent is sequentially guided to the temperature-controlled room 13, the meter 14, the vaporization chamber 16, the separation unit 17, and the detector 18. The recovered solvent is guided to a pipe 26 provided in the temperature-controlled room 13 of the quantification unit 15 and flows through the pipe 26 toward the meter 14. The recovered solvent in the pipe 26 is pressurized by the above-described pressurizing mechanism, and is pressurized to 0.3 MPa [gauge] in this embodiment. Note that the notation with “[gauge]” at the end like this pressure value means a gauge pressure obtained by subtracting the atmospheric pressure from the absolute pressure. Since the pipe 26 is accommodated in the chamber 27 and the first temperature control mechanism 28 controls the temperature by heating the inside of the chamber 27, the pipe 26 is suppressed from temperature change due to the temperature outside the chamber 27, While passing through the pipe 26, the temperature of the recovered solvent reaches a specific temperature. Even if the temperature of the recovered solvent supplied to the temperature-controlled room 13 changes, the recovered solvent is brought to a specific temperature by heating in the temperature-controlled room 13. Thus, the temperature of the recovered solvent is adjusted to a specific temperature by the first temperature control mechanism 28 via the chamber 27 and the pipe 26. For example, by adjusting the temperature inside the chamber 27 to 50 ° C., the recovered solvent is adjusted to 50 ° C. By this temperature adjustment, an error in the amount sampled in the subsequent sampling step is suppressed as compared with the case where the temperature adjustment step is not performed, and the calculation accuracy of the mass ratio of the solvent component is improved. Further, even when sampling is repeated a plurality of times, errors are suppressed and a certain amount is accurately sampled.

  Here, the boiling point of the recovered solvent is TL (unit: ° C.). Further, when the temperature of the recovered solvent is increased by heating, the upper limit temperature at which the gas phase does not appear, that is, the upper limit temperature at which the recovered solvent is held only in the liquid phase (referred to as the liquid phase holding upper limit temperature) is TV (units). ; ° C.). The liquid phase retention upper limit temperature TV is usually higher than (TL-30) ° C. and lower than TL. The aforementioned specific temperature in the temperature-controlled room 13 is preferably in the range of (TL-30) ° C. or higher and lower than TL ° C., and more preferably TV ° C. or lower. This is a viewpoint of setting the temperature as high as possible within the range in which the vaporization is suppressed, that is, the range in which the liquid state is maintained. By setting the above-mentioned specific temperature within this range, the error in the amount sampled in the subsequent sampling step is further reduced, and the entire amount of the sample is quickly and reliably converted into the gas in the vaporization chamber 16. Therefore, the calculation accuracy of the mass ratio of the solvent component is further improved. The above-mentioned specific temperature in the pressurized state may be obtained by obtaining the boiling point under the pressure as the TL and obtaining the liquid phase holding upper limit temperature under the pressure as the TV. The boiling point TL and the liquid phase holding upper limit temperature TV may be obtained, for example, by heating the recovered solvent that is a liquid and raising the temperature before setting the specific temperature described above. In the present embodiment, the boiling point TL and the liquid phase retention upper limit temperature TV are obtained by separately sampling from the recovered solvent and heating the sampled sample to raise the temperature.

  When a plurality of solvent components contained in the recovered solvent are azeotropic substances, the azeotropic point is defined as the above TL, and when it is not an azeotropic substance, the boiling point of the solvent component having the lower boiling point is defined as the above TL. Dichloromethane and methanol in the recovery solvent of the present embodiment are azeotropic substances, and the azeotropic point is 79.6 ° C. under 0.3 MPa [gauge], which is TL. And by adjusting the above-mentioned specific temperature to a constant temperature within the range of (TL-30) ° C. or more and less than TL, compared to each case where the temperature is set to a temperature of (TL-30) ° C. or less and TL or more, It has been confirmed that the calculation accuracy of the mass ratio of the solvent component is further improved. Specifically, under 0.3 MPa [gauge], in each case of adjusting to 49.6 ° C., 65 ° C., and 79.5 ° C., adjusting to lower than 49.6 ° C. and adjusting to 79.6 ° C. It has been confirmed that the calculation accuracy of the mass ratio of the solvent component is reliably improved and the calculation accuracy of the mass ratio of the solvent component is more reliably improved than in the case where temperature adjustment is not performed. .

  The liquid phase retention upper limit temperature TV of the recovered solvent in the present embodiment is 65 ° C. under 0.3 MPa [gauge], and the specific temperature is within the range of 50 ° C. or more and 65 ° C. or less under 0.3 MPa [gauge]. The temperature is adjusted to a certain level. Thereby, compared with the case where a temperature control process is not implemented, it is confirmed that the calculation accuracy of the mass ratio of a solvent component improves dramatically. Specifically, under 0.3 MPa [gauge], the temperature is adjusted in each case of adjusting to (TV-15) ° C. of 50 ° C., 58 ° C., and TV ° C. of 65 ° C. It has been confirmed that the calculation accuracy of the mass ratio of the solvent component is improved by about 5 times compared to the case where the solvent component is not present.

  The recovered solvent adjusted to a specific temperature is guided from the temperature-controlled room 13 to the meter 14, and a specific amount to be supplied to the vaporization chamber 16 is sampled as a sample. The recovered solvent guided to the measuring instrument 14 is preliminarily set to a specific temperature in the temperature-controlled room 13, and is measured while maintaining this temperature. Accurately sampled. Further, even when sampling is repeated a plurality of times, errors are suppressed and a certain amount is accurately sampled.

  The sample is heated by the vaporizing chamber 16 and vaporized in its entirety. Since the sample guided to the vaporization chamber 16 is adjusted in advance to a specific temperature by the quantification unit 15, it is easy to set the temperature condition in the vaporization chamber 16, and the gas is generated at a specific vaporization rate by the heating mechanism of the vaporization chamber 16. become.

  Since the temperature in the vaporization chamber 16 is maintained at a constant temperature by the second temperature control mechanism 31, the vaporization rate of the sample is constant, and therefore the detector 18 detects the amount of each solvent component more accurately. .

  The sample vaporized in the vaporizing chamber 16 is guided to the column 32 in a gaseous state, and passes through the column 32 by the carrier gas 35. The sample is separated into each solvent component by the chromatographic mechanism while moving downstream in the column tube 32a while being held in the stationary phase 32b. Each of these solvent components exits the column 32 in order of the moving speed and is sent to the detector 18.

  Detection is started by the detector 18, and a detection signal that changes in accordance with the amount of the solvent component per unit time is sent to the composition calculator 19. Further, the detection signal is integrated by the detector 18 so that the peak areas for the detected solvent components are sequentially obtained. Each time the peak area is obtained, the peak area is converted into the amount of the solvent component and sent to the composition calculator 19. Each solvent component detected by the detector 18 is discharged from the detector 18 and discarded.

  In the identification unit 19a, the retention time is measured based on the change in the detection signal, and the compound as each solvent component is identified based on the measured retention time. Then, for each identified solvent component, the mass ratio is calculated based on the amount of each solvent component from the detector 18 by the ratio calculator 19b. Thereby, the mass ratio of the solvent component contained in the recovered solvent is obtained. By passing through the temperature control step described above, the error in the mass ratio of the solvent component obtained can be kept small.

  When calculating the mass ratio of the solvent component a plurality of times, a series of steps including a temperature adjustment step, a sampling step, a vaporization step, a separation step, a detection step, and a ratio calculation step are repeated. In this case, the specific temperature in each temperature adjustment step is made the same. That is, the specific temperature in the second and subsequent temperature adjustment steps is the same as the specific temperature in the first temperature adjustment step. Thereby, the mass ratio of the solvent component in which the error of each time is suppressed is obtained. Note that the “same” regarding the specific temperature is most preferable from the viewpoint of suppressing errors if it is exactly the same, but it may not be exactly the same.

  The analysis unit 10 is used by being disposed, for example, in a solvent recovery preparation device 63 (see FIG. 4) of a solution casting apparatus 60 (see FIG. 4) described later. The film 50 shown in FIG. 2 is an example manufactured by the solution casting apparatus 60 embodying the present invention. The film 50 has a three-layer structure, and includes a film main body 52 and a pair of surface layers 53 disposed on the surface of the film main body 52. Although the boundary between the film main body 52 and the surface layer 53 is not observed, FIG. 2 shows these boundaries for convenience of explanation. In the present embodiment, the film 50 having a three-layer structure including the film main body 52 and the pair of surface layers 53 is manufactured, but the film to be manufactured is not limited thereto. For example, a film having a two-layer structure in which the surface layer 53 is provided only on one surface of the film body 52 and the film body 52, or a film body having a multilayer structure may be used.

The film body 52 is composed of cellulose acylate and an additive, but may not include the additive. The pair of surface layers 53 are composed of the same components. Specifically, all the surface layers 53 are composed of cellulose acylate, fine particles, and additives, and the ratios thereof are also the same. The surface layer 53 may not include at least one of fine particles and additives. The additive is a plasticizer, an ultraviolet absorber, a retardation control agent for controlling the retardation of the film 50, or the like. The fine particles function as a so-called matting agent that enhances scratch resistance and slipperiness of the film 50 and prevents sticking when the film 50 is stacked. The fine particles are provided so as to protrude from the film surface 50a, thereby giving the film surface 50a a certain roughness and forming minute irregularities, but the illustration is omitted in FIG. Even if the films 50 overlap each other due to the unevenness, the films 50 do not stick to each other, the sliding between the films 50 is secured, and a certain scratch resistance is exhibited. For example, silica (silicon dioxide, SiO ₂ ) is used as the fine particles.

  The cellulose acylate of the film body 52 and the surface layer 53 is TAC. However, each cellulose acylate of the film main body 52 and the surface layer 53 is not limited to this. For example, the cellulose acylate of the film body 52 may be cellulose diacetate (DAC), and the cellulose acylate of the surface layer 53 may be TAC. Moreover, in this embodiment, although each polymer component of the film main body 52 and the surface layer 53 has made cellulose acylate, what is necessary is just a polymer which can be made into a film by the solution casting method. Examples of other polymers include cyclic polyolefin and acrylic.

  Both surface layers 53 may be composed of the same components, and the ratios thereof may be different from each other. Further, only one of the surface layers 53 may include fine particles.

  The thickness T10 of the film 50 is 60 μm, the thickness T12 of the film body 52 is 54 μm, and the thickness T13 of the surface layer 53 is 3 μm. However, each thickness is not limited thereto, and the thickness T10 may be in the range of 10 μm to 80 μm, the thickness T12 may be in the range of 9 μm to 70 μm, and the thickness T13 may be in the range of 1 μm to 10 μm.

  This film 50 can be used for a polarizing plate. As shown in FIG. 3, the polarizing plate 56 includes a polarizing film 57 and a film 50 disposed on both film surfaces of the polarizing film 57. The film 50 functions as a protective film for protecting the polarizing film 57. When the film 50 has an optical compensation function, it functions as a protective film having an optical compensation function. The film 50 is a second film that uses a solvent having a higher mass ratio of dichloromethane than the first dope 66 (see FIG. 4) for forming the film body 52 by a solution casting apparatus 60 (see FIG. 4) described later. A surface layer 53 is formed by doping 67 (see FIG. 4). For this reason, the film 50 has a polarizing film 57 and a film having a single layer structure manufactured only from the first dope 66 and a film having a multilayer structure in which the surface layer is formed without using the second dope 67. The adhesion of is strong.

  As shown in FIG. 4, the solution casting apparatus 60 embodying the present invention includes a dope preparation device 61, a solution casting device 62, and a solvent recovery preparation device 63. The dope preparing device 61 is for preparing a first dope 66 as a first polymer solution in which TAC 77 is a polymer component and a second dope 67 as a second polymer solution. That is, the dope preparation device 61 is for a polymer solution preparation step for preparing each polymer solution for forming the film 50. The dope preparation device 61 includes dissolution units 72 and 73 and a mixing / dispersing unit 74.

  When the TAC 77 and the first solvent 68 are supplied, the dissolution unit 72 performs at least one of heating and stirring on the mixture. As a result, the dissolving unit 72 dissolves the TAC 77 in the first solvent 68. The dissolving part 73 has the same configuration as the dissolving part 72. When the TAC 77 and the second solvent 69 are supplied, the TAC 77 is dissolved in the second solvent 69 by at least one of heating and stirring.

  In the present embodiment, the first solvent 68 and the second solvent 69 are each a mixture of dichloromethane and methanol. The 1st solvent 68 is a reference | standard solvent used for each preparation of the 2nd solvent 69 and the various solvent of dope which manufactures another film. The second solvent 69 has a mass ratio of dichloromethane to methanol higher than that of the first solvent 68 by adding dichloromethane to the first solvent 68 as described later. Specifically, the mass ratio of dichloromethane: methanol in the first solvent 68 is 833: 155, and this mass ratio in the second solvent is 870: 130. However, dichloromethane: methanol in the first solvent 68 and the second solvent 69 is not limited to this, and the mass ratio of dichloromethane in the second solvent 69 is set to 833: 155 to 900: 100. If it is higher than the above, the effect of improving the above-mentioned adhesion can be obtained with certainty. In addition, the range of said mass ratio includes each mass ratio of a minimum and an upper limit. The first solvent 68 and the second solvent 69 may be a three-component system in which 1-butanol is further added or a four-component system in which a small amount of water is added thereto.

  When the TAC 77, the second solvent 69, and the fine particles 78 are supplied, the mixing and dispersing unit 74 stirs the mixture, for example, thereby dissolving the TAC 77 in the second solvent 69 and dispersing the fine particles 78. In order to disperse the fine particles 78 efficiently and reliably, an ultrasonic oscillator is provided in the mixing and dispersing unit 74, and ultrasonic waves are applied to the mixture of the TAC 77, the second solvent 69 and the fine particles 78 by this ultrasonic oscillator. The obtained fine particle dispersion 79 is added to the TAC solution obtained in the dissolving section 73 and stirred by a stirrer (not shown) until the fine particles 78 are dispersed in a uniform state. The additive 80 is added to the TAC solution obtained by the dissolving portion 72 and the TAC solution in which the fine particles 78 are uniformly dispersed, and the first dope 66 and the second solvent 69 using the first solvent 68 are added. Then, the second dope 67 is used. The prepared first dope 66 and second dope 67 may be once stored in a storage container or the like.

  The solution casting apparatus 62 is for a solution casting process for producing the film 50 from the first dope 66 and the second dope 67, and includes a casting die 81, a belt 82, rollers 83 and 84, a tenter 85, A roller drying unit 86, a winding unit 87, a peeling roller 89, and the like are included.

  The casting die 81, the belt 82, and the rollers 83 and 84 are for continuously forming a casting film 88 in which the first dope 66 and the second dope 67 overlap. The belt 82 is an endless casting support formed in an annular shape. The belt 82 is wound around the circumferential surfaces of the roller 83 and the roller 84. At least one of the roller 83 and the roller 84 has a drive unit (not shown), and is rotated in the circumferential direction by the drive unit. By this rotation, the belt 82 in contact with the peripheral surface moves in the longitudinal direction. The casting die 81 disposed on the belt 82 continuously flows out the first dope 66 and the second dope 67 in a state where the first dope 66 is sandwiched and overlapped by the second dope 67. In the present embodiment, an air supply unit (not shown) is provided so as to face the casting surface on which the casting film 88 of the belt 82 is formed. This air supply part emits gas and proceeds to dry the casting film 88 passing therethrough. The stripping roller 89 is for stripping the casting film 88 that has been dried to the extent that it can be transported. At the time of stripping, the film 50 is supported by the stripping roller 89, and the stripping position where the casting film 88 is stripped from the belt 82 is kept constant. A drum (not shown) may be used in place of the belt 82 and the rollers 83 and 84.

  The tenter 85 proceeds to dry the film 50 while holding each side of the film 50 with a clip 85a as a holding member. The tenter 85 extends the width of the film 50 by applying tension in the width direction while holding the film 50 with the clip 85a and transporting the film 50 in the longitudinal direction. The tenter 85 is provided with a gas supply unit 85 b that supplies a dry gas by flowing it in the vicinity of the film 50. A pin may be used instead of the clip 85a. The clip 85a holds the film 50, and the pins hold the film 50 by penetrating the film 50 in the thickness direction.

  The roller drying unit 86 is for drying the film 50 while transporting it. The roller drying unit 86 includes a plurality of rollers 86a arranged in the conveyance direction of the film 50, an air conditioner (not shown), and a chamber (not shown). Among the plurality of rollers 86a, there is a driving roller that rotates in the circumferential direction, and the film 50 is conveyed downstream by the rotation of the driving roller. The air conditioner is connected to the condenser 91 (see FIG. 5) of the solvent recovery preparation device 63, sucks the atmosphere inside the chamber of the roller drying unit 86, and sends the sucked gas to the condenser 91. When a gas from which the first solvent 68, the second solvent 69, and moisture have been removed is supplied from the condenser 91, the gas is adjusted to a target temperature and sent into the chamber again. Thereby, the temperature and humidity inside the chamber are kept constant. A tenter (not shown) having the same configuration as the tenter 85 may be provided between the tenter 85 and the roller drying unit 86.

  The winding unit 87 winds the long film 50 supplied from the roller drying unit 86 in a roll shape. A cooling chamber (not shown) may be provided between the roller drying unit 86 and the winding unit 87. This cooling chamber cools the film 50 passing through the interior to room temperature before winding.

  In the solution casting apparatus 62, since the casting film 88 and the film 50 are dried, the first solvent 68 and the second solvent 69 are vaporized as solvent gas. The solvent recovery preparation device 63 recovers the first solvent 68 and the second solvent 69 vaporized by the solution casting apparatus 62 as solvent gas, and supplies the first solvent 68 and the second solvent newly supplied to the solution casting apparatus 62. This is for preparing the solvent 69. The details of the solvent recovery preparation device 63 will be described later with reference to another drawing.

  The operation of the above configuration will be described. The TAC 77 for the first dope 66 is sent to the dissolving part 72, and the TAC 77 for the second dope 67 is sent to the dissolving part 73 and the mixing / dispersing part 74. In the dissolving part 72, the TAC 77 is dissolved in the first solvent 68 to form a TAC solution. The first dope 66 is obtained by adding the additive 80 to the TAC solution. In the dissolving portion 73, TAC 77 is dissolved in the second solvent 69 to form a TAC solution. In the mixing and dispersing unit 74, the TAC 77 is dissolved in the second solvent 69, and the fine particles 78 are dispersed to form a fine particle dispersion 79. The second dope 67 is obtained by adding the additive 80 after the fine particle dispersion 79 is added to the TAC solution from the dissolving portion 73.

  The first dope 66 and the second dope 67 are continuously sent to the casting die 81. By continuously flowing the first dope 66 and the second dope 67 from the casting die 81 onto the moving belt 82, the second dope 67, the first dope 66, and the second dope 67 overlapped in this order. A casting film 88 having a layer structure is continuously formed on the belt 82 (casting process). The casting film 88 is dried by a blower and peeled off from the belt 82 by the peeling roller 89 in a state containing the first solvent 68 and the second solvent 69 to form the film 50. The film 50 at the time of peeling is a so-called wet film in which the first solvent 68 and the second solvent 69 remain. When the belt 82 circulates and returns from the stripping position to the casting position where the first dope 66 and the second dope 67 are cast, new first dope 66 and second dope 67 are cast again.

  The casting film 88 peeled off by the peeling roller 89, that is, the film 50 is guided to the tenter 85. In the tenter 85, the width of the film 50 can be changed at a predetermined timing by the clip 85a while the film 50 is being transported and drying is promoted by the dry gas from the gas supply unit 85b.

  The film 50 is guided from the tenter 85 to the roller drying unit 86 and is dried while passing through the chamber (not shown) of the roller drying unit 86. As described above, the long film 50 formed by continuously peeling the casting film 88 from the belt 82 is dried by the tenter 85 and the roller drying unit 86 (drying process). The dried film 50 is guided to the winding unit 87 and wound up in a roll shape. The atmosphere in the solution casting apparatus 62 is sent to the solvent recovery and preparation apparatus 63 in a state containing a solvent gas composed of the first solvent 68 and the second solvent 69 evaporated from the casting film 88 and the film 50. The solvent gas is removed. For example, in this embodiment, a chamber (not shown) surrounding the casting die 81 and the belt 82, a chamber (not shown) that covers the transport path of the film 50 in the tenter 85, a chamber of the roller drying unit 86 as described above, and the like. The atmosphere of these chambers is sent to the solvent recovery and preparation device 63 in a state containing the solvent gas, and the solvent gas is removed. The gas from which the solvent gas has been removed is sent to the solution casting apparatus 62 again. The solvent gas is recovered by the solvent recovery / preparation device 63, converted into new first solvent 68 and second solvent 69, and supplied to the dope preparation device 61.

  In the above example, the film 50 is manufactured by the co-casting of the first dope 66 and the second dope 67, but it may be replaced with sequential casting using a plurality of casting dies.

  As shown in FIG. 5, the solvent recovery preparation device 63 includes a condenser 91, a first distillation column 92, a second distillation column 93, first to third analysis units 101 to 103, and flow meters 105 to 108. And an extractor 111, a preparation calculator 112, first to sixth tanks 121 to 126, and the like. The condenser 91 is used to convert the solvent gas into a liquid recovery solvent 131, and the atmosphere of the solution casting apparatus 62 is sent to the condenser 91. The atmosphere contains a solvent gas, and the condenser 91 collects the atmosphere in a gaseous state, condenses the solvent gas contained in the gas by cooling, and recovers the liquid recovered solvent 131. (Recovery process).

  The first tank 121 and the second tank 122 are for storing the recovered solvent 131. The first tank 121 stores the recovered solvent 131 that is continuously sent from the condenser 91. For example, a specific amount of the recovered solvent 131 is sent from the first tank 121 to the second tank 122 at a specific timing. The delivery of the recovered solvent 131 from the first tank 121 to the second tank 122 may be continuous. The recovered solvent 131 in the second tank 122 is sent to the first distillation column 92.

  The first distillation column 92 is for a first distillation step in which impurities are removed by distilling the recovered solvent 131. The impurities are those other than the solvent components used for the components of the first solvent 68 and the second solvent 69. This impurity is water in this embodiment. In the present embodiment, since the first distillation column 92 does not separate the solvent components contained in the first solvent 68 and the second solvent 69, the distilled solvent 132 obtained by this distillation is separated from the first solvent 68. It is a mixture with the second solvent 69. For this reason, the distilled solvent 132 is a mixture of dichloromethane and methanol, and the mass ratio of dichloromethane and methanol is different from that of the first solvent 68 and also different from that of the second solvent 69. As described above, when the first solvent 68 and the second solvent 69 are three-component systems further containing 1-butanol, the first distillation column 92 converts the mixture of 1-butanol and water to dichloromethane and Separate from the mixture with methanol. In this case, the mixture of 1-butanol and water is guided to a purifier (not shown) to isolate 1-butanol, and the isolated 1-butanol is separated from the third tank 123 and the fourth tank 124. It may be supplied to and used. Further, as described above, when the first solvent 68 and the second solvent 69 are a four-component system further containing 1-butanol and water, the mixture of 1-butanol and water is separated by the same purification apparatus. The third tank 123 and the fourth tank 124 may be supplied for use. The supply amount of 1-butanol and water to the third tank 123 and the fourth tank 124 is calculated by a preparation calculator 112 described later.

  Distilled solvent 132 is divided into three, first to third distilled solvents. The first distilled solvent is sent to the first analysis unit 101, the second distilled solvent is sent to the second distillation column 93, and the third distilled solvent is sent to the fourth tank 124. Specifically, in the distilled solvent 132, the second distilled solvent is first separated, and the residue obtained by separating the second distilled solvent is sent to the third tank 123 and stored. A part of the water stored in the third tank 123 is sent to the first analysis unit 101 as the first distilled solvent. The residue in the third tank 123 in which the first distilled solvent is separated is sent to the fourth tank 124 for preparing the first solvent 68 as the third distilled solvent.

  The first analysis unit 101 has the same configuration as the analysis unit 10 shown in FIG. 1 and identifies each compound as a solvent component contained in the distilled solvent 132 that is a recovered solvent that has undergone the first distillation step. In order to determine the mass ratio of the solvent component. When impurities are contained, the identification of the impurities and the mass ratio with respect to the solvent component are also obtained. A part of the water stored in the third tank 123 is sent to the first analysis unit 101 as the first distilled solvent, and is discarded after passing through the detector 18 (see FIG. 1). In the present embodiment, by the first analysis unit 101, the distilled solvent 132 is composed of two solvent components, the first compound as the first solvent component is dichloromethane, and the second compound as the second solvent component is methanol. Is identified. The mass ratio of dichloromethane: methanol is calculated as 838: 150. The first analysis unit 101 outputs the calculation result as a detection signal to the preparation calculator 112, and outputs the identification result as a detection signal to the second distillation column 93.

  The preparation computing unit 112 calculates the flow rate by the flow meter 105 based on the detection signal of the first analysis unit 101, and from the third tank 123 of the third distilled solvent via the flow meter 105 based on the calculation result. The flow rate to the fourth tank 124 is controlled.

  The second distillation column 93 is for a second distillation step in which the second distilled solvent is distilled to separate every contained solvent component. The second distillation column 93 includes a recording unit, a calculation unit, and a distillation column main body (all not shown), and the recording unit previously has a plurality of distillation conditions (distillation patterns) corresponding to the boiling point and amount of each compound. Is recorded. The distillation conditions are determined in consideration of the latent heat of vaporization and specific heat of the compound to be separated. When the detection signal from the first analysis unit 101 is input, the calculation unit specifies distillation conditions for separating each solvent component based on the detection signal. The computing unit controls the distillation column body to the specified distillation conditions, and the distillation column body distills the second distilled solvent. However, if the contained solvent component is known, the recording section may not be provided, and the distillation column main body may be controlled to the distillation conditions corresponding to the contained solvent component. By this distillation, the second distilled solvent is separated into contained solvent components, that is, dichloromethane 133 and methanol 134. The dichloromethane 133 and the methanol 134 are used for fine adjustment of the components when the first solvent 68 is prepared, and the dichloromethane 133 is also used for addition when the second solvent 69 is prepared.

  The extractor 111 is for purifying the dichloromethane 133. Since the dichloromethane 133 and the methanol 134 are azeotropic substances, the dichloromethane 133 obtained by the second distillation column 93 contains methanol. For example, in the present embodiment, methanol is contained in dichloromethane at a ratio of 8 to 90% of the mass of dichloromethane. Therefore, the dichloromethane 133 is purified using the extractor 111 as in the present embodiment to remove methanol. The extractor 111 separates methanol on the water phase side from dichloromethane on the oil phase side by two-phase separation of the water phase and the oil phase. In this embodiment, hexane is used as the oil phase extract. The separated dichloromethane is sent to the fifth tank 125 and stored. The extractor 111 is provided as appropriate according to the type of compound.

  The dichloromethane 133 used for fine adjustment of the components of the first solvent 68 and the addition when preparing the second solvent 69 is the one in the fifth tank 125 that has undergone the extraction process by the extractor 111. When the dichloromethane 133 in the fifth tank 125 is used for fine adjustment of the first solvent 68, the flow rate is controlled by the flow meter 106 and supplied to the above-described fourth tank 124 to prepare the second solvent 69. When used for the addition, the flow rate is controlled by the flow meter 108 and mixed with a part separated from the first solvent 68. Control of the flow rate by the flow meters 106 and 108 will be described later.

  Since the dichloromethane 133 in the fifth tank 125 is used for the preparation of the first solvent 68 and the second solvent 69, it is preferable to grasp the purity as accurately as possible. Therefore, as in the present embodiment, it is preferable to provide the second analysis unit 102 in the solvent recovery preparation apparatus 63 and obtain the purity of dichloromethane by the second analysis unit 102. The second analysis unit 102 has the same configuration as the analysis unit 10 shown in FIG. 1 and calculates the mass ratio of impurities as the purity of the dichloromethane 133. The second analysis unit 102 outputs the calculation result to the preparation calculator 112 as a detection signal. The preparation calculator 112 calculates each flow rate by the flow meter 106 and the flow meter 108 based on the detection signal, and controls the flow meter 106 and the flow meter 108 based on the calculation result. Thereby, the flow rate of the dichloromethane 133 from the fifth tank 125 to the fourth tank 124 and the flow rate to a part separated from the first solvent 68 as described later are controlled. In the present embodiment, the purity of dichloromethane 133 is calculated to be 99% by mass or more.

  Methanol 134 obtained by distillation by the second distillation column 93 is stored in the sixth tank 126, the flow rate of which is controlled by the flow meter 107, and the fourth tank 124 is supplied. Since the methanol 134 is used for fine adjustment when preparing the first solvent 68 as the reference solvent, it is preferable to grasp the purity as accurately as possible. Therefore, as in the present embodiment, it is preferable to provide the third analysis unit 103 in the solvent recovery preparation device 63 and obtain the purity of methanol by the third analysis unit 103. The third analysis unit 103 has the same configuration as the analysis unit 10 shown in FIG. 1 and calculates the mass ratio of impurities as the purity of the methanol 134. The third analysis unit 103 outputs this calculation result to the preparation calculator 112 as a detection signal. The preparation calculator 112 calculates the flow rate by the flow meter 107 based on this detection signal, and the flow rate of the methanol 134 from the sixth tank 126 to the fourth tank 124 via the flow meter 107 based on the calculation result. Be controlled. In the present embodiment, the purity of methanol 134 is calculated to be 99% by mass or more.

  As described above, the third distilled solvent is sent to the fourth tank 124, and dichloromethane 133 and methanol 134 are added to the third distilled solvent in the determined addition amounts. When the first solvent 68 is a ternary system of dichloromethane 133, methanol, and water, or when the first solvent 68 is a quaternary system of dichloromethane 133, methanol, 1-butanol, and water, 1- Butanol and water are also added to the third distilled solvent in a determined addition amount. Thus, the first solvent 68 is obtained (first solvent preparation step). The feeding amount of the third distilled solvent and the addition amounts of dichloromethane 133 and methanol 134 are determined by calculation by the preparation calculator 112. In the preparation computing unit 112, a mass ratio of dichloromethane 133 and methanol 134 as the first solvent to be prepared is recorded in advance. When the detection signals from the first to third analysis units 101 to 103 are input as described above, the preparation computing unit 112 compares the recorded mass ratio with the third mass to the fourth tank 124. The distillation amount of the distilled solvent and the addition amounts of dichloromethane 133 and methanol 134 are calculated. In addition, each addition amount of dichloromethane 133 and methanol 134 may be calculated as zero. For example, in the present embodiment, the mass ratio of dichloromethane: methanol recorded for the first solvent 68 is 833: 155, the feed rate of the third distilled solvent is 70 kg / min, and the addition amount of dichloromethane 133 is 1. 7 kg / min and the amount of methanol 134 added are calculated to be 0.25 kg / min.

  In this embodiment, the recovered solvent 131 in the first tank 121 may be supplied to the fourth tank 124 in addition to the third distilled solvent, dichloromethane 133, and methanol 134. For example, the first solvent 68 includes a specific amount of water. Therefore, in the present embodiment, a part separated from the recovered solvent 131 in the first tank 121 is provided to the first analysis unit 101, and identification of each contained solvent component and calculation of the mass ratio of the solvent component are performed. Is going. The first analysis unit 101 outputs this calculation result as a detection signal to the preparation calculator 112, and the preparation calculator 112 controls the flow rate of the recovered solvent 131 to the fourth tank 124 based on this detection signal.

  In addition, a part of the solvent in the fourth tank 124 is separated, and this part is provided to the first analysis unit 101 to calculate the mass ratio of dichloromethane, methanol, and water contained therein. When the detection signal of the calculation result is input from the first analysis unit 101, the preparation calculator 112 further adds the third distillation to the solvent in the fourth tank 124 to make the first solvent 68 based on the detection signal. The flow rate of the used solvent, dichloromethane 133, methanol 134, and recovered solvent 131 is calculated and sent to the fourth tank 124. In this way, the solvent in the fourth tank 124 is repeatedly detected and finely adjusted by detecting the mass ratio of the solvent component, so that the first solvent 68 having a constant mass ratio of the solvent component is obtained. For example, new purchased dichloromethane, methanol, butanol, or pure water may be added to the fourth tank 124 for fine adjustment. Each addition amount in this case is calculated by the preparation calculator 112.

  Part of the obtained first solvent 68 is separated, and the remaining part is provided to the dope preparation device 61. Also, to the part separated from the first solvent 68, dichloromethane 133 is fed from the fifth tank 125 and added at a flow rate controlled by the flow meter 108 as described above, whereby the second solvent 69 is added. Obtained (second solvent preparation step). The obtained second solvent 69 is supplied to the dope preparation device 61.

  By the above method, even if the recovered solvent 131 has a mass ratio of the solvent component different from that of the first solvent 68 and the second solvent 69, the new first solvent 68 and the second solvent 69 have a mass ratio of the solvent component. Each is prepared uniformly. In addition, even when the film manufacturing process is switched when the film is manufactured with the dope using the first solvent 68 and the second solvent 69 from the case where the film is manufactured with the dope using only the first solvent 68, A new first solvent 68 is prepared with a constant mass ratio of the solvent components. Furthermore, even if the mass ratio of the solvent component in the recovered solvent 131 changes over time, the new first solvent 68 is prepared so that the mass ratio of the solvent component is constant.

  In the above example, the first solvent 68 and the second solvent 69 are recovered and used again for the first dope 66 and the second dope 67 to be used for the casting die 81. The new second solvent 69 may be used for the first dope 66 and the second dope 67 used for another casting die different from the casting die 81. The above example is for reusing the recovered solvent recovered from the solution casting process, but the recovered solvent in the present invention is not limited to that from the solution casting process. For example, a case where a mixture of a plurality of liquid organic compounds is reused or a case where a mixture of a liquid organic compound and water is reused may be used. Further, the solvent is not limited to a solvent for dissolving the polymer, and may be a solvent for dissolving the oligomer or the monomer.

DESCRIPTION OF SYMBOLS 10 Recovery solvent analysis unit 13 Constant temperature chamber 14 Metering device 16 Vaporization chamber 18 Detector 19b Ratio calculation part 26 Pipe 27 Chamber 28 1st temperature control mechanism 32 Column 32b Stationary phase 50 Film 60 Solution film-forming equipment 61 Dope preparation apparatus 62 Solution manufacture Membrane device 63 Solvent recovery preparation device

Claims (8)

A temperature adjusting step of adjusting the temperature of the recovered solvent recovered as a liquid mixture to a specific temperature by heating; and
A sampling step of sampling a specific amount from the recovered solvent while maintaining the specific temperature;
A vaporization step of vaporizing the sample sampled in the sampling step by heating;
A separation step of guiding the sample vaporized to a column having a stationary phase, and separating the solvent component contained in the sample by passing through the column with a carrier gas as a mobile phase;
A detection step for detecting the amount of each separated solvent component;
And a ratio calculating step of calculating a mass ratio of the solvent component based on each detected amount.   The method for analyzing a recovered solvent according to claim 1, wherein when the boiling point of the recovered solvent is TL ° C, the specific temperature is in the range of (TL-30) ° C or higher and lower than TL ° C. When calculating the mass ratio of the solvent component multiple times,
Repeating a series of steps of the temperature adjustment step, the sampling step, the vaporization step, the separation step, the detection step, and the ratio calculation step,
The method for analyzing a recovered solvent according to claim 1 or 2, wherein the specific temperature in each temperature adjustment step is the same.   The temperature adjusting step includes a tube that guides the recovered solvent, a chamber that accommodates the tube and divides the space surrounding the tube and an external space, and a temperature control mechanism that controls the internal temperature of the chamber. The method for analyzing a recovered solvent according to any one of claims 1 to 3, wherein the recovered solvent is adjusted to the specific temperature by passing the tube through a chamber. A temperature adjusting means for adjusting the recovered solvent recovered as a liquid mixture to a specific temperature by heating;
A sampling unit for sampling a specific amount from the recovered solvent while maintaining the temperature of the recovered solvent guided from the adjusting means at the specific temperature;
A vaporizing means for vaporizing the sampled sample by heating;
A stationary phase in which the vaporized sample is guided, and a column in which a carrier gas as a mobile phase for guiding the sample through the stationary phase is guided;
A detector for detecting the amount of each solvent component separated by the column;
A recovery solvent analysis unit comprising: a ratio calculation unit that calculates a mass ratio of the solvent component based on each amount detected by the detection unit. The solvent evaporated in the solution casting process for producing a film from a polymer solution in which a polymer is dissolved in a solvent that is a mixture of the first solvent component and the second solvent component is recovered and used as a recovery solvent. In the solvent recovery preparation method for preparing a new solvent,
A recovery step of recovering the solvent evaporated in the solution casting step in a gaseous state and condensing it into a liquid recovery solvent;
A first distillation step of distilling the recovered solvent to remove impurities to form a distilled solvent that is a mixture of the first solvent component and the second solvent component;
Dividing the distilled solvent into first to third distilled solvents, of which the first distilled solvent is heated to raise the temperature by heating to a specific temperature; and
A sampling step of sampling a specific amount from the first distilled solvent while maintaining the specific temperature;
A vaporization step of vaporizing the sample sampled in the sampling step by heating;
The first solvent component and the second solvent contained in the sample are guided by guiding the sample vaporized in the vaporization step to a column having a stationary phase and passing through the column with a carrier gas as a mobile phase. A separation step of separating into components;
A detection step of detecting each amount of the first solvent component and the second solvent component separated in the separation step;
A ratio calculation step for calculating a mass ratio between the first solvent component and the second solvent component based on each amount detected in the detection step;
A second distillation step of separating the second distilled solvent into the first solvent component and the second solvent component by distilling the second distilled solvent;
The addition amounts of the first solvent component and the second solvent component are respectively determined based on the mass ratio calculated in the ratio calculation step, and the addition amount of the first solvent component and the second solvent component are obtained in the second distillation step. Adding a first solvent component and the second solvent component to the third distilled solvent to prepare a first new solvent for use in a subsequent solution casting step; ,
By adding the first solvent component obtained in the second distillation step to a portion separated from the first new solvent, the mass ratio of the first solvent component over the first new solvent And a second solvent preparation step of preparing a second new solvent having a high value.   In the solution casting step, the polymer is dissolved in the first polymer solution in which the polymer is dissolved in the first solvent and the second solvent in which the mass ratio of the first solvent component is higher than that of the first solvent. The method for recovering and preparing a solvent according to claim 6, wherein the film having a multilayer structure is produced from the second polymer solution. A first polymer solution is prepared by dissolving the polymer in the first new solvent obtained by the solvent recovery preparation method according to claim 6, and the polymer is dissolved in the second new solvent. A polymer solution preparation step of preparing the polymer solution of 2,
A casting step of forming a casting film by continuously flowing from the casting die to a casting support that moves the first polymer solution and the second polymer solution;
A solution casting method comprising a drying step of continuously peeling the casting membrane from the casting support and drying it.

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