JP2008080736A - Solution film forming equipment and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely regulate an additive component quantity in a dope. <P>SOLUTION: An additive charging device 19 for charging an additive 36 in a raw material dope 35 is provided, and a first near infrared spectral analyzer 100 is provided on the upstream side of the additive charging device 19 while a second near infrared spectral analyzer 102 is provided on the downstream side of the additive charging device 19. The component quantity of the raw material dope 35 is calculated on the basis of the absorbance spectrum data outputted from the first near infrared spectral analyzer 100 to determine the corrected adding quantity of the additive 36. The dope 9 is prepared on the basis of the determined corrected adding quantity. The component quantity of the dope 9 is calculated on the basis of the absorbance spectrum data outputted from the second near infrared spectral analyzer 102, and in a case that the component quantity of the additive 36 does not reach a target value, the correction of the corrected adding quantity is performed. By this method, the additive component quantity in the dope can be precisely regulated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a solution casting apparatus and method for producing a polymer film.

  A TAC film formed from a cellulose ester, particularly a cellulose triacetate (hereinafter referred to as “TAC”) having an average degree of acetylation of 58.0% to 62.5%, is characterized by its toughness and flame retardancy. It is used as a film support. In addition, since the TAC film is excellent in optical isotropy, it is also used as a protective film for a polarizing plate of a liquid crystal display device whose market is expanding in recent years.

  As a method for producing a TAC film, a solution casting method is well known. The solution casting method can produce a film having excellent physical properties such as optical properties as compared with other production methods such as a melt casting method. In the solution casting method, a polymer dope is first dissolved in a mixed solvent containing dichloromethane or methyl acetate as a main solvent to form a raw material dope, and an ultraviolet absorber (UV agent), a matting agent, a retardation control agent, a plastic is formed on this raw material dope. A dope is prepared by mixing various additives such as an agent. Next, a dope is cast on a support from a casting die to form a casting film. Then, after the cast film becomes self-supporting on the support, the cast film is peeled off from the support as a wet film, dried, and then wound into a roll form as a product film.

In general, in the above-described solution casting method, as a raw material dope material, in addition to a new polymer and a mixed solvent, a recycled raw material such as a cleaning waste liquid and a recycled chip is used (for example, Patent Documents 1 and 2). reference). The cleaning waste liquid is generated when cleaning the dope flow path and the filter of the dope preparation facility. In addition, recycled chips are produced by using product rolls in which the product film is wound into rolls (winding misalignment products) or ear-cutting chips generated during film formation, and are crushed into small pieces. ing. In addition, quality rejected products are not suitable as recycled chips and are excluded from recycled materials.
JP 2003-236863 A JP 2003-291116 A

  By the way, if the component amount of the raw material dope additive is not constant, characteristic unevenness occurs in the film after film formation. In order to suppress the occurrence of this characteristic unevenness, it is necessary to accurately grasp the component amount of the raw material dope additive. In the above-mentioned Patent Document 2, a sample is taken from the ear cutting scraps, the components thereof are analyzed, and based on the analysis results, additives are added in the dope supply line to the casting die, and appropriate additive components are added. It is adjusted so that However, when adjusting the amount to be added based on the sampling results from the ear swarf, the accuracy may be increased due to the distance between the additive input position and the sampling collection position and the occurrence of a time lag for the analysis time. There is a problem that it is difficult to make the components of the additive constant, and there is a high possibility that the certain section will be a quality rejected product that does not become a product, resulting in a decrease in production efficiency.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a solution casting apparatus and method capable of accurately adjusting the amount of additive components in the dope.

  The present invention supplies a dope containing a polymer and a solvent from a dope supply line to a casting die, and casts the dope from the casting die on a traveling support to form a casting film on the support. Then, after the casting film is dried to have self-supporting property, the film is peeled off to obtain a wet film, and the wet film is dried to obtain a polymer film. A dope component amount adjusting device that is provided in the dope supply line and adjusts the amount of the dope component by adding an additive into the dope, and provided in the dope supply line upstream of the dope component amount adjusting device. The dope component amount becomes a target value based on the measurement result of the first dope component amount measuring device for measuring the dope component amount online and the first dope component amount measuring device. And a controlling device for adjusting the component amount of said doped by Uni said doped component amount adjusting device.

  A second dope component amount measuring device that is provided in a dope supply line downstream of the dope component amount adjusting device and that measures the dope component amount online; It is preferable to correct the additive input amount of the dope component amount adjusting device based on the measurement result.

  The first and second dope component amount measuring devices determine the absorbance in the spectral wavelength region having a correlation with the component amount in the dope from the absorbance spectrum obtained by measuring the dope with a near-infrared spectrometer. It is preferable to obtain the dope component amount from the absorbance based on a calibration curve showing the relationship between the dope component amount and the absorbance prepared in advance. Moreover, it is preferable that the raw material of the dope includes an ear dust film and a winding slip film.

  In the present invention, a dope containing a polymer and a solvent is cast from a casting die on a traveling support, a cast film is formed on the support, and the cast film is dried to be self-supporting. In the solution casting method for obtaining a polymer film by drying the wet film after the film is held, the first on-line dope component measurement provided in the dope supply line to the casting die A component amount of the dope is measured by an apparatus, a deviation amount from a target value is obtained based on the component amount of the dope by the first dope component amount measuring device, and the first dope is adjusted so as to be the target value. An additive is added by a dope component amount adjusting device provided on the downstream side of the component amount measuring device to adjust the component amount of the dope.

  The dope component amount is measured by an on-line second dope component amount measuring device provided on the downstream side of the dope component amount measuring device, and the dope component is based on the dope component amount by the second dope component amount measuring device. It is preferable to correct the additive input amount of the amount adjusting device.

  The first and second dope component amount measuring devices determine the absorbance in the spectral wavelength region having a correlation with the component amount in the dope from the absorbance spectrum obtained by measuring the dope with a near-infrared spectrometer. It is preferable to obtain the dope component amount from the absorbance based on a calibration curve showing the relationship between the dope component amount and the absorbance prepared in advance.

  In the present invention, since the dope component amount is adjusted by the dope component amount adjusting device based on the on-line measurement result by the first dope component amount measuring device, a sample is collected from the ear cutting waste (ear waste film) or the like. The amount of the dope component (the amount of the additive component) can be adjusted with high accuracy without the need to do so. Thereby, generation | occurrence | production of the quality defect product with which the amount of additive components is not constant is suppressed. In addition, the time required for adjusting the component amount of the additive can be significantly shortened. For this reason, it is possible to prevent a certain section of the product film from becoming a rejected product that does not become a product as in the prior art, so that a reduction in production efficiency can be suppressed.

  Based on the result of online measurement by the second dope component amount measuring device, the additive input amount of the dope component amount adjusting device is corrected, so that the adjustment of the dope component amount (additive component amount) is more accurate. Can be done well.

  Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments given here.

[material]
In the present embodiment, cellulose acylate is used as the polymer, and among the cellulose acylates, the substitution degree of the acyl group to the hydroxyl group of cellulose satisfies all of the following formulas (a) to (c). Are preferred, and triacetylcellulose (TAC) is particularly preferred.
(A) 2.5 ≦ A + B ≦ 3.0
(B) 0 ≦ A ≦ 3.0
(C) 0 ≦ B ≦ 2.9
A and B represent the substitution degree of the acyl group with respect to the hydrogen atom in the hydroxyl group in the cellulose, A is the substitution degree of the acetyl group, and B is the substitution degree of the acyl group having 3 to 22 carbon atoms. In addition, it is preferable that 90 mass% or more of TAC is a particle | grain of 0.1-4 mm. The polymer applicable to the present invention need not be limited to cellulose acylate.

  Glucose units having β-1,4 bonds constituting cellulose have free hydroxyl groups at the 2nd, 3rd and 6th positions. Cellulose acylate is a polymer obtained by esterifying some or all of these hydroxyl groups with an acyl group having 2 or more carbon atoms. The degree of acyl substitution means the ratio of esterification of the hydroxyl group of cellulose for each of the 2nd, 3rd and 6th positions. However, the degree of substitution 1 is 100% esterification.

  The total degree of acylation substitution, that is, the value of DS2 + DS3 + DS6 is preferably 2.00 to 3.00, more preferably 2.22 to 2.90, and particularly preferably 2.40 to 2.88. The DS6 / (DS2 + DS3 + DS6) value is preferably 0.28 or more, more preferably 0.30 or more, and particularly preferably 0.31 to 0.34. DS2 is the ratio at which the hydrogen of the hydroxyl group at the 2-position in the glucose unit is substituted with an acyl group (hereinafter referred to as “the substitution degree of the acyl group at the 2-position”). DS3 is the ratio at which the hydrogen of the hydroxyl group at the 3-position in the glucose unit is substituted with an acyl group (hereinafter referred to as “acyl group substitution degree at the 3-position”). DS6 is the ratio at which the hydrogen of the hydroxyl group at the 6-position in the glucose unit is substituted with an acyl group (hereinafter referred to as “the substitution degree of the acyl group at the 6-position”).

  The acyl group used in the cellulose acylate of the present invention may be only one type or two or more types. When two or more types of acyl groups are used, one of them is preferably an acetyl group. The sum of the degree of substitution of hydroxyl groups at the 2nd, 3rd and 6th positions by acetyl groups is DSA, and the sum of the degree of substitution of the hydroxyl groups at the 2nd, 3rd and 6th positions by acyl groups other than acetyl groups When DSB is DSB, the value of DSA + DSB is preferably 2.22 to 2.90, and particularly preferably 2.40 to 2.88.

  The DSB is preferably 0.30 or more, particularly preferably 0.7 or more. In DSB, 20% or more is preferably the substitution degree of the hydroxyl group at the 6-position, more preferably 25% or more, still more preferably 30% or more, and particularly preferably 33% or more. Further, the DSA + DSB value at the 6-position of the cellulose acylate is 0.75 or more, more preferably 0.80 or more, and particularly preferably 0.85 or more. By using these cellulose acylates, a solution (dope) having excellent solubility can be prepared. In particular, when a non-chlorine organic solvent is used, a dope having excellent solubility, low viscosity and excellent filterability can be prepared.

  Cellulose, which is a raw material for cellulose acylate, may be obtained from, for example, linter cotton or pulp cotton.

  The acyl group having 2 or more carbon atoms of the cellulose acylate of the present invention may be an aliphatic group or an aryl group and is not particularly limited. These are, for example, cellulose alkylcarbonyl esters, alkenylcarbonyl esters, aromatic carbonyl esters, aromatic alkylcarbonyl esters, and the like, each of which may further have a substituted group. Preferred examples of these include propionyl, butanoyl, pentanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, hexadecanoyl, octadecanoyl, iso-butanoyl, t-butanoyl, cyclohexanecarbonyl, olenoyl, benzoyl, A naphthyl carbonyl, a cinnamoyl group, etc. can be mentioned. Among these, propionyl, butanoyl, dodecanoyl, octadecanoyl, t-butanoyl, olenoyl, benzoyl, naphthylcarbonyl, cinnamoyl and the like are more preferable, and propionyl and butanoyl are particularly preferable.

  In the present invention, a compound capable of dissolving cellulose acylate is used as the dope solvent. Examples of the solvent include aromatic hydrocarbons (eg, benzene, toluene, etc.), halogenated hydrocarbons (eg, methylene chloride, chloroform, chlorobenzene, etc.), alcohols (eg, methanol, ethanol, n-propanol, n-butanol, Diethylene glycol, etc.), ketones (eg, acetone, methyl ethyl ketone, etc.), esters (eg, methyl acetate, ethyl acetate, propyl acetate, etc.) and ethers (eg, tetrahydrofuran, methyl cellosolve, etc.). In the present invention, the dope refers to a polymer solution or dispersion obtained by dissolving or dispersing a polymer in a solvent.

  Among these, halogenated hydrocarbons having 1 to 7 carbon atoms are preferably used, and dichloromethane is most preferably used. In addition to dichloromethane, one kind of alcohol having 1 to 5 carbon atoms is used from the viewpoint of physical properties such as solubility of TAC, peelability from cast film support, mechanical strength of film, and optical properties of film. It is preferable to mix several kinds. The content of the alcohol is preferably 2% by mass to 25% by mass and more preferably 5% by mass to 20% by mass with respect to the entire solvent. Specific examples of the alcohol include methanol, ethanol, n-propanol, isopropanol, n-butanol and the like, but methanol, ethanol, n-butanol or a mixture thereof is preferably used.

  By the way, recently, for the purpose of minimizing the influence on the environment, studies on the use of a solvent composition when dichloromethane is not used are in progress. In this examination, an ether having 4 to 12 carbon atoms, a ketone having 3 to 12 carbon atoms, an ester having 3 to 12 carbon atoms, and an alcohol having 1 to 12 carbon atoms are preferably used. Alternatively, these are mixed and used as appropriate. For example, a mixed solvent of methyl acetate, acetone, ethanol, and n-butanol can be mentioned. These ethers, ketones, esters and alcohols may have a cyclic structure. A compound having two or more functional groups of ether, ketone, ester and alcohol (—O—, —CO—, —COO— and —OH) can also be used as the solvent.

  The details of cellulose acylate are described in paragraphs [0140] to [0195] of JP-A-2005-104148. These descriptions can also be applied to the present invention. The dope is mixed with various additives such as an ultraviolet absorber (UV agent), a matting agent, a retardation control agent, and a plasticizer. These additives are also described in paragraphs [0196] to [0516] of JP-A-2005-104148, and these descriptions can also be applied to the present invention.

[Dope production line]
The dope 9 is manufactured using the above raw materials. As shown in FIG. 1, the dope production line 10 constituting the solution film-forming facility (line) of the present invention includes a solvent tank 11, a dissolution tank 12, a washing waste liquid tank 14, a hopper 15, and a heating device 16. A temperature controller 17, an additive charging device 19, a static mixer 20, and a filtering device 22 are provided. The dope production line 10 is connected to a casting die 42 provided in a film production line 40 (see FIG. 2) described later.

  A solvent 24 is stored in the solvent tank 11. The solvent 24 is sent to the dissolution tank 12 by opening and closing the valve 25. The cleaning waste liquid tank 14 stores cleaning waste liquid 26 used for cleaning the dope flow path and the filter of the dope production line 10. As the cleaning liquid used for cleaning, a solvent used for the dope is used. The cleaning liquid is collected after being used for cleaning, and is stored as a cleaning waste liquid 26 in the cleaning waste liquid tank 14. The cleaning waste liquid 26 is sent to the dissolution tank 12 by opening / closing the valve 27.

  A TAC powder (flakes) 28 is accommodated in the hopper 15. The powder 28 is formed from a recycled chip in addition to a new TAC. Here, the regenerated chip is a piece of TAC (product) film 39, which will be described later, or a product (winding misalignment product) that has been wound with a product roll obtained by winding the TAC film 39 into a roll form. The powder 28 is added to the dissolution tank 12 while being measured by the hopper 15.

  The dissolution tank 12 includes a jacket 12a that encloses the outer surface thereof, and a first stirrer 30 that is rotated by a motor 29a. Further, a second agitator 31 that is rotated by a motor 29b is attached to the dissolution tank 12. The melting tank 12 is temperature-controlled by flowing a heat transfer medium (not shown) through the jacket 12a. By appropriately selecting and using the types of the first stirrer 30 and the second stirrer 31, the swelling liquid 32 in which the TAC is swollen in the solvent 24 is prepared. The first stirrer 30 is preferably provided with anchor blades, while the second stirrer 31 is preferably a dissolver type eccentric stirrer.

  The swelling liquid 32 prepared in the dissolution tank 12 is sent to the heating device 16 by a pump 34. The heating device 16 includes a pipe with a jacket, and heats the swelling liquid 32. With this heating device 16, the solid content in the swelling liquid 32 is dissolved to prepare the raw material dope 35. In the present specification, a dope before mixing the additive described later is referred to as a raw material dope, and a dope in which an additive is mixed with the raw material dope is referred to as a dope. The raw material dope 35 is sent to the temperature controller 17 and the temperature is adjusted to approximately room temperature.

  Various additives 36 are added to the raw material dope 35 that has passed through the temperature controller 17 from an additive charging device 19 corresponding to the dope component amount adjusting device of the present invention. Examples of the additive 36 used in the present embodiment include a UV agent, a matting agent, a retardation control agent, and a plasticizer. Each additive 36 is previously dissolved in a solvent or a binder (preferably cellulose acylate). In addition, each additive 36 may be added directly, and the addition method may be appropriately changed according to each additive.

  The additive charging device 19 is provided with a plurality of additive tanks 37_1 to 37_n in which the additives 36 are separately stored. And the addition amount of each additive 36 is adjusted by controlling the opening and closing of the valve | bulb 38, opening amount, etc. of each tank 37_1-37_n. Since the addition control of each additive 36 will be described later, the description thereof is omitted here.

  A static mixer 20 is provided downstream of the additive charging position. The static mixer 20 mixes the raw material dope 35 and each additive 36 to prepare the dope 9. The dope 9 is filtered by the filtering device 22. Thereby, impurities contained in the dope 9 are removed. The dope 9 after the filtration is sent to the casting die 42 of the film production line 40.

[Film production line]
A method of manufacturing the TAC (product) film 39 using the dope 9 obtained above will be described. As shown in FIG. 2, the film production line 40 constituting the solution casting apparatus of the present invention includes a casting die 42, a casting film drying equipment 43, a casting band 46 stretched over rotating rollers 44, 45, It includes a tenter device 48, an ear clip device 50, a drying device 51, a cooling device 52, and a winding device 53.

  The casting die 42 is supplied with the dope 9 from the dope production line 10 described above. The casting film drying equipment 43 provided downstream of the casting die 42 applies drying air to the casting film 69 formed by casting from the casting die 42 to dry the casting film 69. Let

  The rotating rollers 44 and 45 are rotated by a driving device (not shown), and the casting band 46 travels endlessly by this rotation. A heat transfer medium circulation device 63 is attached to the rotating rollers 44 and 45 in order to set the surface temperature of the casting band 46 to a predetermined value. The heat transfer medium circulation device 63 passes the heat transfer medium at a predetermined temperature through a heat transfer medium flow path (not shown) formed inside the rotation rollers 44 and 45, thereby passing the heat transfer medium through the rotation rollers 44 and 45. The heat is transferred to the casting band 46.

  The casting die 42, the casting band 46, and the like are disposed in the casting chamber 64. The casting chamber 64 is provided with a temperature control facility 65 that keeps the internal temperature at a predetermined temperature, and a condenser (condenser) 66 that condenses and recovers the volatile organic solvent. A recovery device 67 is provided outside the casting chamber 64, and the recovery device 67 recovers the organic solvent condensed and liquefied by the condenser 66. Further, a decompression chamber 68 is attached to the casting die 42, and the decompression chamber 68 controls the pressure of the back surface portion of the casting bead formed from the casting die 42 to the casting band 46. Note that the decompression chamber 68 may be omitted. Note that the organic solvent recovered by the condenser 66 may also be reused as a raw material for the raw material dope 35 in the above-described dope production line 10.

  When the casting film 69 has self-supporting properties on the casting band 46, the casting film 69 is peeled off from the casting band 46 as a wet film 74 while being supported by the peeling roller 75.

  The crossover unit 80 is provided with a blower 81. A tenter device 48 is disposed downstream of the crossover unit 80. The tenter device 48 dries the wet film 74 while holding it with a tenter clip (not shown). Further, the wet film 74 is stretched in the width direction while being dried inside the tenter device 48. The wet film 74 that has exited the tenter device 48 is sent to the ear opener 50 on the downstream side of the tenter device 43 as a largely dried TAC film 39.

  The ear clip device 50 cuts out the side end portion (ear portion) of the TAC film 39. The TAC film 39 from which the ears have been cut off is sent to a drying device 51 downstream of the ear cutting device 50. Further, the cut ear scraps (ear scrap film) are finely cut by the crusher 90 to become the above-mentioned recycled chip. The formed chips are collected, processed into TAC powder 28, and reused as a recycled material.

  The drying device 51 is provided with a number of rollers 91. These rollers 91 cover the TAC film 39 and dry both sides of the TAC film 39 evenly. The dried TAC film 39 is guided by a roller 91 to a cooling device 52 downstream of the drying device 51. In the drying device 51, solvent gas is generated from the TAC film 39. This solvent gas is adsorbed and recovered by an adsorption recovery device 92 provided outside the drying device 51. The temperature of the drying device 51 is preferably in the range of 50 ° C. or higher and 160 ° C. or lower.

  The TAC film 39 exiting from the drying device 51 is cooled by the cooling device 52 to approximately room temperature. A humidity control chamber (not shown) for blowing air adjusted to a predetermined humidity and temperature to the TAC film 39 may be provided between the drying device 51 and the cooling device 52. By providing this humidity control chamber, it is possible to suppress the occurrence of curling of the TAC film 39 and winding failure by the winding device 53 described later.

  A forced static elimination device 93 (static elimination bar) that adjusts the charged voltage of the TAC film 39 to a predetermined range (for example, −3 kV to +3 kV) is provided downstream of the cooling device 52. A knurling roller 94 for embossing knurling is provided on both edges of the TAC film 39 downstream thereof.

  The TAC film 39 provided with the knurling is wound up by the winding roller 95 in the winding device 53. In the winding device 53, a press roller 96 for controlling the tension on the TAC film 39 at the time of winding is provided on the outer periphery of the winding roller 95. Then, the winding misalignment product in which the winding misalignment occurred during the winding is cut into chips finely like the above-mentioned ear-cut scraps, and then processed into the TAC powder 28, and the material of the raw material dope 35 Used as

  As described above, the TAC film 39 thus obtained can be used for a film support of a photographic photosensitive material, a protective film for a polarizing plate of a liquid crystal display device, or the like.

[Additive control method]
Next, the addition control of each additive 36 by the above-described additive charging device 19 will be described with reference to FIGS. 1 and 3. In the present embodiment, the component amount of the material dope 35 (particularly each additive 36) formed by using a part of the recycled material (cleaning waste liquid 26 and regenerated chip) at the upstream side of the addition position of each additive 36 first. , And a correction addition amount of each additive 36 is determined so that the component amount of the dope 9 (each additive 36) becomes a target value, and each additive 36 is charged. Next, the component amount of each additive 36 contained in the dope 9 into which each additive 36 has been charged and mixed with the previously determined correction addition amount is measured on the downstream side of the filtering device 22, and based on this measurement result To correct the correction addition amount.

  Of the additives 36, the amount of UV agent or matting agent is very small. For this reason, in this embodiment, control of these addition amounts is not performed, but only the control of the addition amounts of the retardation control agent and the plasticizer (hereinafter referred to as both agents if necessary) is performed.

  The component amounts of the raw material dope 35 and the dope 9 are measured using a known near infrared spectroscopy. Near-infrared spectroscopic analysis method irradiates a measurement object (dope) with near-infrared light in a short wavelength region, and uses an optical sensor to measure measurement light such as scattered reflected light, scattered transmitted light, or transmitted reflected light from the measured object. By detecting the absorbance spectrum of the measurement object, the absorbance in the spectral wavelength region having a correlation intrinsic to the component amounts of the raw material dope 35 and the dope 9 is obtained, and the raw material dope 35 is obtained from the absorbance based on the calibration curve prepared in advance. And the amount of the component of the dope 9 is calculated. Since the retardation control agent and plasticizer used in the production of the TAC film 39 have an amide bond, the amount of components can be measured without any problem by near infrared spectroscopy.

  For the above-described measurement of the absorbance spectrum, a Fourier transform type near-infrared spectrometer (hereinafter simply referred to as a near-infrared spectrometer) is used. In the present embodiment, the first near-infrared spectrometer 100 is provided between the temperature controller 17 and the addition position of each additive 36, and the second near-red light is provided between the filtration device 22 and the casting die 42. An outer spectroscopic analyzer 102 is provided. Both near-infrared spectrometers 100 and 102 constitute the first and second dope component amount measuring devices of the present invention together with a data processing unit 106 (see FIG. 3) to be described later. Measurement light obtained from a probe (not shown) inserted in a pipe through which 9 flows is Fourier-transformed to measure an absorbance spectrum (see FIG. 4). Thereby, online measurement of the raw material dope 35 and the dope 9 becomes possible. As the near-infrared spectrometers 100 and 102, “InfraSpec NR800” manufactured by Yokogawa Electric Corporation is used in this embodiment.

  When the raw material dope 35 passes through the first near-infrared spectrometer 100, the absorbance spectrum data measured by the first near-infrared spectrometer 100 once every second, for example, is stored in the main controller 104 (see FIG. 3). ) Is input to the data processing unit 106. The main controller 104 includes a data processing unit 106, an addition amount determination unit 108, a memory 110, an addition control unit 112, and the like, and controls each unit of the dope production line 10.

FIG. 4 shows an example of the absorbance spectrum. The absorbance peak (peak intensity) in the spectral wavelength range (wave number range) indicated by A in the figure has a correlation with the component amount (mass%) of cellulose, which is the raw material of TAC contained in the dope, and the solvent 24. . The peak intensity in the spectral wavelength region indicated by B in the figure has a correlation with the component amount of moisture (H ₂ O) contained in the dope. The peak intensity in the spectral wavelength region indicated by C in the figure has a correlation with the amount of the component of the retardation control agent contained in the dope. The peak intensity in the spectral wavelength region indicated by D in the figure has a correlation with the amount of the plasticizer component contained in the dope.

  As shown in FIG. 3, when the absorbance spectrum data is input from the first near-infrared spectrometer 100, the data processing unit 106 has a peak intensity in a spectral wavelength range that correlates with the component amounts of the retardation control agent and the plasticizer. Ask for. Next, the data processing unit 106 searches the calibration curve for the retardation control agent and the calibration curve for the plasticizer stored in the calibration curve database 114. In the calibration curve database 114, a calibration curve of a measurement object for measuring the component amount is stored in advance.

  FIG. 5 shows an example of a calibration curve. The calibration curve associates the absorbance (peak intensity) of the measurement object with the component amount (mass%). This calibration curve is created based on absorbance spectrum data obtained by measuring a measurement object with a known component amount. Then, the component amount can be calculated by substituting the peak intensity obtained from the absorbance spectrum data into the calibration curve.

  Therefore, as shown in FIG. 3, the data processing unit 106 substitutes the peak intensities of the retardation control agent and the plasticizer into the corresponding calibration curve in the calibration curve database 114, and calculates the respective component amounts. Thereby, the component amount of the retardation control agent and the plasticizer contained in the raw material dope 35 is obtained. At this time, the component amounts of TAC, solvent, and water contained in the raw material dope 35 may be obtained simultaneously by the same procedure. Then, the calculation result of the component amount obtained by the data processing unit 106 is input to the addition amount determining unit 108.

  The addition amount determination unit 108 constitutes a control device of the present invention together with an addition control unit 112 described later. This addition amount determination unit 108 adds to the raw material dope 35 based on the difference between the calculation result of the retardation control agent and plasticizer component amounts and the target value of the component amounts of both agents determined for each type of TAC film 39. The corrected addition amount of each additive 36 to be determined is determined. The target values of the component amounts of both agents can be freely set by an operator via an operation panel (not shown). When determining the corrected addition amount of each additive 36, the corrected addition amount of each additive 36 is determined by taking into account the TAC, solvent, and moisture component amounts contained in the raw material dope 35 as necessary. It may be. Then, the determined corrected addition amount data of each additive 36 is stored in the memory 110.

  The correction addition amount of the retardation control agent and the plasticizer stored in the memory 110 is read out by the addition control unit 112 that controls the additive charging device 19 described above. The addition control unit 112 adds the additives so that the raw material dope 35 measured by the first near-infrared spectrometer 100 passes through the additive injection device 19 and both agents are added by the correction addition amount. The device 19 is controlled. Specifically, as described above, in each of the additive tanks 37_1 to 37_n (see FIG. 1), the tank valve 38 (see FIG. 1) in which the retardation control agent is stored, and the plasticizer are stored. By controlling the opening and closing of the valve 38 and the opening amount of the tank, both agents are added to the raw material dope 35 by the correction addition amount. In addition, the method of controlling the addition amount of each additive 36 containing both agents is not limited to this, You may use various methods.

  As described above, the UV agent and the matting agent are added in a predetermined amount. In addition, before adding each additive 36, you may make it mix these with a mixer.

  As described above, the raw material dope 35 to which each additive 36 is added is mixed by the static mixer 20 to prepare the dope 9. The prepared dope 9 is filtered by the filtering device 22 and then passes through the second near-infrared spectrometer 102. Similarly, absorbance spectrum data measured by the second near-infrared spectrometer 102 is input to the data processing unit 106.

  When the absorbance spectrum data is input from the second near-infrared spectrometer 102, the data processing unit 106 calculates the amounts of the retardation control agent and plasticizer contained in the dope 9 in the same manner. Then, the addition amount determination unit 108 determines whether or not the calculation results of the component amounts of the new retardation control agent and plasticizer have reached the target values described above. If the target value has not been reached, a correction coefficient (for example, 0.95, 0.93, 1.02) for correcting to reach the target values of the component amounts of both agents is added to the addition amount correction unit of the addition amount determination unit 108 The correction addition amount is corrected by obtaining 108a and multiplying the correction addition amount by this correction coefficient. The corrected correction addition amount data is overwritten on the correction addition amount data previously stored in the memory 110.

  The addition control unit 112 controls the additive charging device 19 as described above based on the corrected corrected addition amount data read from the memory 110. Thereby, since the retardation control agent and the plasticizer are added to the raw material dope 35 by the corrected correction addition amount determined, the component amounts of both agents can be made closer to the target values. Hereinafter, the component amount of the additive 36 is measured and charged in accordance with the timing at which the raw material dope 35 (dope 9) passes through each device or apparatus, and the correction addition amount is corrected.

  Note that the additive component amount cannot be finely adjusted for the dope 9 that has passed through the second near-infrared spectrometer 102 (additive charging device 19) before correction. Therefore, the component amount of the dope 9 (each additive 36) is stored in the memory 110 or the like, and when a film failure occurs later in the TAC film (product film) 39, the dope 9 and the TAC film 39 See correspondence. Since the correspondence between the dope 9 and the TAC film 39 is known for the length of each process, the process of the dope 9 passing through each process to become the TAC film 39 can be simulated. Based on this, the correspondence between the dope 9 and the TAC film 39 can be known. Therefore, the amount of the dope (additive) component at each position of the TAC film 39 can be known, and can be used as an element for pursuing the cause of failure.

  Next, the flow of addition control of each additive 36 (retardation control agent, plasticizer) will be described with reference to FIG. When the operation of the dope production line 10 is started, the solvent 24, the cleaning waste liquid 26, and the TAC powder 28 are mixed in the dissolution tank 12 to prepare the swelling liquid 32. The swelling liquid 32 is sent to the heating device 16 and heated. Thereby, the solid content in the swelling liquid 32 is dissolved and the raw material dope 35 is prepared. The prepared material dope 35 is temperature-adjusted to about room temperature by the temperature controller 17 and then passes through the first near-infrared spectroscopic analyzer 100.

  When the raw material dope 35 passes through the first near-infrared spectrometer 100, the absorbance spectrum data measured by the first near-infrared spectrometer 100 is input to the data processing unit 106 of the main controller 104. The data processing unit 106 obtains peak intensities (see FIG. 4) in the spectral wavelength region that correlate with the component amounts of the retardation control agent and the plasticizer, and calibrates both agents stored in the calibration curve database 114. By substituting into the line (see FIG. 5), the component amounts of both agents are calculated.

  The retardation control agent and plasticizer component amounts calculated by the data processing unit 106 are input to the addition amount determination unit 108. The addition amount determination unit 108 determines the corrected addition amount of both agents to be added to the raw material dope 35 based on the difference between the calculation result of the component amounts of both agents and the target value of the component amounts of both agents. The determined corrected addition amount data of both agents is stored in the memory 110.

  The addition control unit 112 reads the correction addition amount data of the retardation control agent and the plasticizer stored in the memory 110, and the raw material dope 35 measured by the first near-infrared spectrometer 100 is used as the additive dosing device 19. At the time of passing, the additive charging device 19 is controlled so that both agents are added by the determined correction addition amount. Thereby, both agents are added to the raw material dope 35 by the correction addition amount. At the same time, a UV agent and a matting agent are added in a predetermined amount.

  The raw material dope 35 and each additive 36 are mixed by the static mixer 20 to prepare the dope 9. The prepared dope 9 is filtered by the filtering device 22 and then passes through the second near-infrared spectrometer 102. At this time, the absorbance spectrum data measured by the second near-infrared spectrometer 102 is input to the data processing unit 106. When the absorbance spectrum data is input from the second near-infrared spectrometer 102, the data processing unit 106 calculates the amounts of the retardation control agent and plasticizer contained in the dope 9 in the same manner. As described above, the component amount of the dope 9 (both agents) is stored in the memory 110 or the like so that the component amount of the dope (both agents) at each position of the TAC film 39 can be known.

  Next, the addition amount determination unit 108 determines whether or not the calculation results of the component amounts of the new retardation control agent and the plasticizer have reached the target values of the component amounts of both agents described above. When the target value has not been reached, the addition amount correction unit 108a corrects the correction addition amount by multiplying the correction addition amount by the correction coefficient. The corrected correction addition amount data is overwritten on the correction addition amount data previously stored in the memory 110.

  The addition control unit 112 reads the corrected corrected addition amount data newly stored in the memory 110, and controls the additive charging device 19 based on this data. Thereby, both agents are added to the raw material dope 35 by the corrected correction addition amount. Further, a UV agent or a matting agent is added in a predetermined amount.

  As described above, in the present embodiment, this measurement is performed by measuring the component amounts of the additives 36 (retardation control agent and plasticizer) contained in the raw material dope 35 and the dope 9 using near infrared spectroscopy. Based on the result, the addition amount of each additive 36 added to the raw material dope 35, that is, the component amount of the dope 9 can be adjusted.

  In the past, samples were collected from the ear swarf, and the amount of additive added was adjusted based on the analysis results obtained by analyzing the components. In addition, due to the occurrence of a time lag corresponding to the analysis time, it has been difficult to make the additive components constant. On the other hand, in the present embodiment, since the amount of additive added can be adjusted without collecting a sample from the ear scraps, it is possible to suppress the occurrence of defective products in which the amount of additive component is not constant. In addition, the time required for adjusting the component amount of the additive can be significantly shortened. For this reason, since it can also prevent that it becomes the quality rejection product which does not become a product in a fixed area like the past, it can suppress a production efficiency fall.

  Further, in the present embodiment, based on the measurement result by the second near-infrared spectrometer 102 provided on the downstream side of the additive charging device 19, correction addition is performed when the component amounts of both agents have not reached the target value. Since the amounts are corrected, the component amounts of both agents can be made closer to the target values.

  In the above embodiment, the first near-infrared spectrometer 100 is provided on the upstream side of the addition position of each additive 36, and the second near-infrared spectrometer 102 is provided on the downstream side. Although the addition amount of both agents is adjusted based on the measurement results of the infrared spectrometers 100 and 102, the present invention is not limited to this. For example, the input amount of both agents may be adjusted based on the measurement result of only one of the first near-infrared spectrometer 100 and the second near-infrared spectrometer 102. In this case, the deviation between the component amounts of both agents contained in the dope 9 and the target value becomes large, but only one near-infrared spectrometer is used, and the line configuration is simplified.

  Moreover, in the said embodiment, before performing correction | amendment of correction | amendment addition amount, the fine adjustment of the component amount of the additive 36 is carried out with respect to dope 9 which passed the 2nd near-infrared spectrometer 102 (additive addition apparatus 19). Although not possible, the present invention is not limited to this. For example, an additive charging device and a static mixer may be provided on the downstream side of the second near-infrared spectrometer 102 to further finely adjust the additive 36 component amount.

  In the above embodiment, the component amount of the additive 36 is measured and charged in accordance with the timing when the raw material dope 35 (dope 9) passes through each device or apparatus, and the correction addition amount is corrected. When the component change of the raw material dope 35 and the dope 9 is small, the component amount measurement and addition of the additive 36 and the correction addition amount may be corrected at an appropriate timing.

  Further, the amount of the additive 36 that can be charged by the additive charging device 19 is affected by the performance of the static mixer 20 and the like. For this reason, when the corrected addition amount does not fall within the range that can be charged by the additive charging device 19, an appropriate amount of the additive 36 may be added in advance in the preparation step of the raw material dope 35 and the subsequent transfer step. .

  Although the description is omitted in the above embodiment, when the type of the TAC film 39 manufactured in the dope manufacturing line 10 and the film manufacturing line 40 is switched, the operator adds each additive 36 corresponding to the new TAC film 39. A component and a target value of the component amount are input via an operation panel (not shown). Thereby, the addition amount of the additive 36 by the additive charging device 19 is adjusted so that the component amount of each additive 36 reaches a new target value. At this time, since the production of the TAC film 39 is continuously performed without stopping the line, the marker agent is added simultaneously by the additive charging device 19 at the time of switching the component of each additive 36 or the amount of the component. May be.

  The marker agent need not have an adverse effect on the film formation, and may be any one that can be easily detected when the TAC film 39 is obtained. You may make it detect a marker agent using a detection apparatus other than visual confirmation. In addition to using a unique marker agent, a specific additive may be increased or decreased only for that portion, and this increased or decreased portion may be used as a marker. Further, this marker agent may be added simultaneously with the addition of the additive 36 based on the corrected addition correction amount. Thereby, the correspondence between the dope 9 adjusted based on the corrected addition amount after correction and the TAC film 39 can be accurately grasped.

  In the above embodiment, the addition amount correction unit 108a of the addition amount determination unit 108 corrects the correction addition amount by multiplying the correction addition amount by the correction coefficient. However, the present invention is not limited to this. Instead, the correction addition amount may be corrected by adding (subtracting) a correction value that is corrected to reach the target value of the component amount of the additive 36 to the correction addition amount.

  In the above embodiment, based on the absorbance spectrum data measured by the first and second near-infrared spectrometers 100 and 102, the data processing unit 106 in the main controller 104 uses the retardation control agent and the plasticizer component amounts. However, the present invention is not limited to this. For example, when the near-infrared spectrometer is a type that stores a calibration curve, the component amount data of each additive may be directly input to the addition amount determination unit 108 of the main controller 104. Further, instead of providing two near-infrared spectrometers, a near-infrared spectrometer having two measurement probes and capable of multi-channel measurement may be provided.

  In the above-described embodiment, only the addition amount of the retardation control agent and the plasticizer among the additives 36 is controlled, but the present invention is not limited to this, and other UV agents and You may make it control addition amount, such as a mat agent.

  Moreover, in the said embodiment, the component amount of TAC, a solvent, and a water | moisture content contained in the raw material dope 35 can be simultaneously calculated from the absorbance spectrum data output from both near-infrared spectrometers 100 and 102. For this reason, the addition amounts of the solvent 24, the cleaning waste liquid 26, and the powder 28 added to the dissolution tank 12 may be adjusted based on these calculation results.

  In the above embodiment, the cleaning waste liquid 28 and the recycled chip are used as the raw material of the raw material dope 35, but only one of them may be used.

  Moreover, although the additive charging device 19 of the said embodiment is provided with several additive tanks 37_1-37_n according to the kind of each additive 36 used, this invention is not limited to this. Instead of the additive charging device 19, an additive charging device of the type in which each additive 36 is dissolved in one additive tank and then added to the raw material dope 35 may be used.

  In the above-described embodiment, the casting band 46 stretched around the rotating rollers 44 and 45 is used as a support, but the present invention is not limited to this and supports a rotating drum (cooling drum). It may be used as a body.

  In the above embodiment, the correction addition amount of each additive 36 is determined based on the measurement result by the first near-infrared spectrometer 100, and the correction addition is further performed based on the measurement result by the second near-infrared spectrometer 102. The amount is corrected, but the present invention is not limited to this. Various adjustment methods may be used as long as the amount of each additive 36 in the dope 9 can be accurately adjusted based on the measurement results of both near-infrared spectrometers 100 and 102.

  In the above embodiment, the dope production line 10 and the film production line 40 for producing the TAC film 39 have been described as examples. However, the present invention is not limited to this, and various polymers are used. The present invention can be applied to equipment for producing a film using a solution casting method.

It is the schematic of a dope manufacturing line. It is the schematic of a film production line. It is a block diagram which shows the electric constitution of the main controller of a dope production line. It is the graph which showed an example of the absorbance spectrum. It is the graph which showed an example of the calibration curve. It is a flowchart of addition control of an additive.

Explanation of symbols

9 Dope 10 Dope Production Line 19 Additive Feeder 24 Solvent 26 Wash Waste 28 Powder 35 Raw Material Dope 36 Additive 39 TAC Film 40 Film Production Line 42 Casting Die 100 First Near Infrared Spectrometer 102 Second Near Red Outer spectroscopic analyzer 104 Main controller 106 Data processing unit 108 Addition amount determination unit 112 Addition control unit 114 Calibration curve database

Claims (7)

A dope containing a polymer and a solvent is supplied from a dope supply line to a casting die, and the dope is cast from the casting die on a traveling support to form a casting film on the support. In a solution casting apparatus for drying a cast film to make it self-supporting and then peeling it off to form a wet film, and drying the wet film to obtain a polymer film.
A dope component amount adjusting device that is provided in the dope supply line immediately before the casting die, and that adds an additive into the dope to adjust the dope component amount;
A first dope component amount measuring device that is provided in the dope supply line upstream of the dope component amount adjusting device and that measures the dope component amount online;
And a control device for adjusting the dope component amount by the dope component amount adjusting device so that the dope component amount becomes a target value based on a measurement result of the first dope component amount measuring device. Solution casting equipment.   A second dope component amount measuring device that is provided in a dope supply line downstream of the dope component amount adjusting device and that measures the dope component amount online; 2. The solution casting apparatus according to claim 1, wherein an additive input amount of the dope component amount adjusting device is corrected based on a measurement result.   The first and second dope component amount measuring devices determine the absorbance in the spectral wavelength region having a correlation with the component amount in the dope from the absorbance spectrum obtained by measuring the dope with a near-infrared spectrometer. 3. The solution casting apparatus according to claim 2, wherein the amount of the dope component is obtained from the absorbance based on a calibration curve indicating a relationship between the amount of the dope component and the absorbance prepared in advance.   The solution casting apparatus according to any one of claims 1 to 3, wherein the dope material includes an ear dust film and a winding slip film. A dope containing a polymer and a solvent was cast from a casting die on a traveling support, and a cast film was formed on the support, and the cast film was dried to have self-supporting properties. In a solution casting method for obtaining a polymer film by peeling off the wet film later and drying the wet film,
The dope component amount is measured by an on-line first dope component amount measuring device provided in the dope supply line to the casting die,
A dope provided on the downstream side of the first dope component amount measuring device so as to obtain a deviation amount from the target value based on the dope component amount by the first dope component amount measuring device and to be the target value. A solution casting method characterized in that an additive is added by a component amount adjusting device to adjust the component amount of the dope. The amount of the dope component is measured by an on-line second dope component amount measuring device provided on the downstream side of the dope component amount adjusting device,
6. The solution casting method according to claim 5, wherein an additive input amount of the dope component amount adjusting device is corrected based on a dope component amount obtained by the second dope component amount measuring device.   The first and second dope component amount measuring devices determine the absorbance in the spectral wavelength region having a correlation with the component amount in the dope from the absorbance spectrum obtained by measuring the dope with a near-infrared spectrometer. The solution casting method according to claim 6, wherein the dope component amount is obtained from the absorbance based on a calibration curve indicating a relationship between the dope component amount and the absorbance prepared in advance.

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