TWI405726B - A method and system for manufacturing a liquid for polarization film - Google Patents

Abstract

The invention provides a recycling system of polarizing film preparing liquid medicine which is able to efficiently recycle the raw material in the waste liquor produced when prepares the polarizing film. The system comprises at least following procedures: pH adjusting procedure, adjusting the pH of the waste liquor from the solution for dipping the polarizing film into the dyeing solution containing iodine and potassium iodide; separating procedure for separating the iodine in the waste liquor as potassium iodide concentration liquor by electrodialysis method; recycling procedure for adjusting the dyeing solution by mixing the potassium iodide concentration liquor and iodine and supplying to the dyeing bath.

Description

Method and system for recycling liquid medicine for producing polarizing film

The present invention relates to a method and system for recycling a polarizing film production chemical solution for recycling iodine and boron from a raw material for producing a waste liquid when a polarizing film is produced.

A polarizing film used for a liquid crystal display or the like is, for example, a polyvinyl alcohol-based film (PVA film) which is generally oriented to adsorb iodine. In the polarizing film, the iodine-based polarizing film is usually produced by immersing a PVA film in which iodine is adsorbed in an aqueous solution containing boric acid. This manufacturing step produces a waste liquid containing iodide ions, boric acid, potassium ions, and water-soluble organic substances. The manufacturing waste liquid is usually discharged by industrial wastewater by a coagulation method, an adsorption method, an ion exchange method, a filtration method, or the like, and is contained in a specific component contained in the waste water, or is reduced by concentration by concentration. After that, it is treated with industrial waste.

However, in recent years, the wastewater standard has become stricter, and in the conventional treatment methods such as the coacervation method, the adsorption method, the ion exchange method, and the filtration method, it is difficult to treat the boron concentration in the wastewater to a value below the reference value. In addition, industrial waste is expected to reduce emissions in terms of processing costs and environmental issues.

Further, as long as boron and iodine can be efficiently recovered from these waste waters, as a raw material for producing a polarizing film, industrial waste can be reduced when recycled, and an attempt can be made to reduce the cost of raw materials.

Generally, when iodine and boron are recovered from waste water, these waste liquids must be concentrated and separated when recycled.

The method for treating a waste liquid for manufacturing a polarizing plate disclosed in the prior art (for example, Patent Document 1) is subjected to electrodialysis through a waste liquid discharged from a polarizing plate manufacturing step, and is separated into a desalting liquid mainly containing an organic component and mainly containing an inorganic component. Concentrate.

However, it is possible to reduce the cost of raw materials and the cost of waste liquid by simply recycling the waste liquid for manufacturing such a polarizing plate, and to reduce the amount of industrial waste, thereby constructing a manufacturing system that considers the environment.

However, the aforementioned advance technology is mainly based on waste liquid treatment, and the technology for recycling iodine and boron after separation and recovery and the detailed conditions for recycling are not reviewed at all.

[Patent Document 1] JP-A-2001-314864

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a method and a system for recycling a production liquid of a polarizing film production process, which can be used for recycling a production liquid which generates a waste liquid from the production of a polarizing film.

In order to solve the above problems, a recycling system for producing a chemical solution for a polarizing film to which the present invention is applied is characterized in that a PVA (polyvinyl alcohol) film for producing a polarizing film is immersed in a dyeing bath for dyeing solution containing iodine and potassium iodide. The waste liquid storage tank for storing the waste liquid and the waste liquid stored in the waste liquid storage tank are adjusted to less than 7, and then the iodine component in the waste liquid is separated by electrodialysis to prepare potassium iodide. The electrodialysis apparatus of the concentrate and the potassium iodide concentrate from the electrodialysis apparatus are added with a new iodine component, and the dyeing solution is adjusted by mixing, and then supplied to the recycled portion of the dyeing bath.

The present invention has a pH adjustment step for adjusting a waste liquid from a PVA (polyvinyl alcohol) film for producing a polarizing film in a dyeing bath for dyeing solution containing iodine and potassium iodide to a pH of 7 or less, and by electrodialysis The iodine in the waste liquid is separated, and a separation step of the potassium iodide concentrate is prepared, and after the new iodine is mixed in the potassium iodide concentrate, the dyeing solution is adjusted, and the recycling step is supplied to the dye bath. Therefore, the potassium iodide concentrate is mixed with iodine, adjusted for the dyeing solution, and then supplied to the dye bath or the like to construct a so-called recycling system. To this end, in addition to reducing industrial waste, it is also intended to reduce the cost of raw materials.

[Best form of implementation of the invention]

Hereinafter, the best mode for carrying out the invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a view showing the constitution of a recycling system 1 for a polarizing film production chemical liquid to which the present invention is applied. The recycling system for producing a polarizing film is used for the dye bath 11 for immersing the PVA (polyvinyl alcohol) film 2 for producing the polarizing film 2, and for the PVA film 2a for immersing in the dye bath 11. The immersed cross-linking bath 12 is disposed in a manufacturing line 20 formed by washing the washing bath 13 of the PVA 2b immersed in the crosslinking bath 12. The recycling system 1 is provided with a waste liquid storage tank 14 for temporarily storing the waste liquid from the dyeing bath 11, the crosslinking bath 12, and the washing bath, and the activated carbon supplied from the waste liquid from the waste liquid storage tank 14. The tank 15 and the electrodialysis unit 16 supplied through the waste liquid of the activated carbon tank 15 and the electrodialysis unit 17 supplied from the desalted liquid from the electrodialysis unit 16 are provided.

The PVA film 2 is a film obtained by forming a polyvinyl alcohol, an ethylene-vinyl acetate copolymer saponified product, or a resin containing a small amount of other copolymerized components. As other polymer components, for example, unsaturated carboxylic acids, olefins, unsaturated sulfonic acids, and the like can also be used.

The degree of polymerization of the PVA resin is usually from 1,000 to 10,000, preferably from 1,500 to 5,000.

The saponification degree of the PVA resin is usually about 85 to 100 mol%, preferably about 98 to 100 mol%.

This PVA film 2 can be applied to any PVA resin film forming method. The film thickness of the polarizing film 2 is not particularly limited, and is generally about 30 μm to 150 μm.

This PVA film was sufficiently swollen in water and then dyed in the dyeing bath 11.

In the dyeing bath 11, a dyeing solution containing iodine and potassium iodide was placed. The composition of the dyeing solution is as follows: the weight ratio of water: iodine: potassium iodide is 100: 0.01 to 0.5: 0.1 to 10. After the PVA film 2 is immersed in the dyeing solution formed by the weight composition, the PVA film 2a which adsorbs iodine on the surface can be formed. The temperature in the dyeing bath 11 is usually 20 to 50 ° C.

The cross-linking bath 12 is provided with a solution for crosslinking which contains boric acid and potassium iodide. The composition of the crosslinking solution is as follows: the weight ratio of water: boric acid: potassium iodide is 100: 1.0 to 7.0: 1.0 to 8.0. After the PVA film 2 is immersed in the cross-linking solution formed by the weight composition, the iodine polymer is crosslinked on the surface of the PVA film 2a to form a stabilized PVA film 2b. That is, the temperature of the crosslinking bath 12 is preferably 40 ° C or higher, more preferably 50 ° C to 85 ° C. Further, the immersion time of the PVA film 2 of the crosslinking solution is not particularly limited, but is usually 10 to 1200 seconds, preferably 30 to 600 seconds.

The washing bath 13 is filled with washing water. The PVA film 2b from the crosslinking bath 12 is immersed in the cleaning bath 13, and impurities or the like adhering to the surface thereof can be removed. Thereafter, after the drying step, a polarizing film is produced from the PVA film 2.

The PVA film 2 is stretched during the immersion in the dye bath 11 to the washing bath 13. The ratio of the final length of the extended PVA film 2 to the initial length of the unstretched PVA film 2 is usually 3 to 7 times, preferably 4 to 6 times.

Further, in order to obtain the polarizing film, an extension device such as a wide roll or a guide can be used to extend the direction in which the extending direction intersects.

Moreover, the manufacturing process until the polarizing film is obtained from the PVA film 2 is not limited to the above-described form, and any other method may be applied.

Further, the protective film may be attached to one side or both sides of the polarizing film obtained as described above. Among them, the protective film is added for the purpose of improving the water resistance and usability of the polarizing film, and an appropriate transparent material can be used for the formation. In particular, plastics such as transparency, mechanical strength, thermal stability, and moisture shielding properties are ideal users. In other words, examples thereof include a polyester resin, an acetate resin, a polyether oxime resin, a polycarbonate resin, a polyamide resin, a polyimide resin, and a polyolefin resin. And a thermoplastic resin such as a propylene resin or the like, a propylene-based or urethane-based acrylamide-based ethyl acrylate, a thermosetting resin such as an epoxy-based or polyfluorene-based resin, or an ultraviolet curable resin. The protective film is exemplified by acetaminophen (TAC), etc., and a polyolefin-based resin such as a cyclic polyolefin having a raw spinel or a polycyclic raw spinylene-based monomer in an amorphous polyolefin-based resin. A resin example of a polymerization unit of an olefin. Further, the transparent protective film for the protective layer can be treated for the purpose of hard coat treatment, anti-reflection treatment, anti-blocking, diffusion to light resistance, etc. without impairing the object of the present invention.

The adhesion treatment between the polarizing film and the protective film is not particularly limited, and is generally, for example, an adhesive made of a vinyl alcohol polymer or a vinyl alcohol polymer such as boric acid, borax, glutaraldehyde, melamine or oxalic acid. A solvent-based adhesive such as a water-soluble crosslinking agent, a solvent-based adhesive such as an epoxy resin, a polyester resin, or a vinyl acetate, or a polymerization reaction hardening agent such as a propylene-based polymer resin or a urethane resin. It is carried out from the obtained adhesive resin or the like. That is, the waste liquid from each of the baths 11 to 13 is collected in a separate bath or in the collected waste liquid storage tank 14. It is also possible to provide a device for concentrating the waste liquid collected in the waste liquid storage tank 14.

The wastewater from the waste storage tank 14 is in the pH adjustment step 21 and adjusted to a pH of less than 7. Further, the water-soluble organic compound (TOC) is removed by passing through the activated carbon tank 15. Thereafter, the waste liquid is introduced into the electrodialysis unit 16. That is, the configuration of the activated carbon tank 15 may be omitted. Further, the activated carbon tank 15 may be set in the subsequent stage of the electrodialysis 17, instead of being disposed in the subsequent stage of the waste liquid storage tank 14, the TOC may be removed.

The electrodialysis device 16 used in the present invention is characterized in that a cation exchange membrane and an anion exchange membrane are alternately disposed between an anode and a cathode, whereby a cation exchange membrane and an anion exchange membrane constitute a plurality of absorption cells. The electrodialysis device applies a direct current between the anode and the cathode, and after introducing the waste liquid into the central electrolytic cell, the iodide ions (iodine component) and potassium ions in the waste liquid are respectively moved to the anode side and the cathode side, respectively. Potassium iodide (KI) is formed in the absorption tanks on both sides of the electrolytic cell. On the other hand, the electrodialysis unit 16 discharges a desalting solution containing an aqueous solution (KI concentrate) of 50 to 150 g/l KI and an amount of iodine of 1.0 g/l or less.

At this time, when the pH of the waste liquid introduced into the electrodialysis device 16 exceeds 7, the amount of boric acid ions increases after the coexistence of boric acid (H ₃ BO ₃ ) is dissociated, and boric acid ions are mixed into the KI concentrate at the time of electrodialysis. On the other hand, when the pH of the waste liquid is less than 7, most of the boric acid does not dissociate in the presence of a molecule. Therefore, even if electrodialysis is performed, the boric acid does not move and is directly discharged into the desalting liquid. Thereby, boron and iodine in the waste liquid can be effectively separated.

Figure 2 shows the pH on the horizontal axis and the concentration of non-dissociated boric acid (H ₃ BO ₃ ) on the vertical axis, which represents the relationship between the pH of the solution and the form of boron. When the pH of the solution is less than 7, most boric acid is not dissociated and is present as a boric acid molecule. Therefore, the pH of the waste liquid charged to the electrodialysis unit 16 is less than 7. Thereby, the dissociation of boric acid can be suppressed, and even if boric acid is not moved by electrodialysis, the amount of boron in the waste liquid is not changed, and the amount of iodine can be reduced.

Further, when the waste liquid is acidic, free iodine is formed, and the ion exchange membrane is deteriorated to reduce the efficiency of electrodialysis. Therefore, the pH of the waste liquid is preferably 3 or more. Thereby, air oxidation of iodide ions can also inhibit the formation of free iodine. Alternatively, the oxidation-reduction potential of the reducing agent such as potassium sulfite which does not generate iodine may be suppressed. At this time, by using a selective membrane of an anion exchange membrane capable of moving monovalent ions, it is possible to prevent the penetration of sulfate ions into the KI concentrate.

The KI concentrated liquid thus obtained is mixed with new iodine, and then adjusted to form a dyeing solution, which is again supplied to the dyeing bath 11. Further, the KI concentrate may be mixed with a new boric acid, adjusted for the crosslinking solution, and then reused for the production of the cross-linking bath 12. In this way, the KI concentrate is separated from the waste liquid, and this is used again as a production chemical solution, so that a so-called recycling system can be constructed. Therefore, industrial waste can be reduced while reducing the cost of raw materials.

In addition, the recycling of the KI concentrate can be carried out by any solution for dyeing and the solution for crosslinking.

Further, a desalting liquid containing boric acid (H ₃ BO ₃ ) and an organic substance separated by the electrodialysis device 16 is added with potassium hydroxide such as NaOH or KOH, preferably KOH, and is adjusted in the pH adjustment step 23 to After the pH is 7 or higher, preferably 9 or more, the electrodialysis device 17 is introduced. In the electrodialysis device 17, boron is separated, and an aqueous solution (boric acid concentrated solution) containing 100 to 500 g/1 of NaB(OH) ₄ and KB(OH) _{4 can} be separated. When the boric acid concentrate is recycled as a solution for crosslinking, the free base is removed, and in the pH adjustment step 23, boric acid in a pH of 4 to 7 is preferably produced. In this method, acid exchange is performed via acid, and ion exchange is performed. The removal of the alkali is carried out, and the solution for iodine crosslinking is adjusted and supplied to the crosslinking bath 12 again. That is, in the pH adjustment step 23, it is preferable that the acid for pH adjustment is hydrogen iodide. Thereby, in the present invention, not only the KI concentrated liquid but also the recycling of the boric acid concentrated liquid can be realized. That is, when the boric acid concentrate is recycled, the KI concentrate obtained as described above may be used as the potassium iodide solution mixed therewith.

Further, in the above-described embodiment, at least the manufacturing system 20 to which the recycling system 11 to which the present invention is applied is disposed in the order of the dyeing bath 11, the crosslinking bath 12, and the washing bath 13 is prepared. Description, and the composition is not limited. The recycling system 1 to which the present invention is applied is also applicable to any manufacturing line in which a bath for impregnating a PVA film exists.

In the bath for impregnating the PVA film, a solution containing iodine and potassium iodide, a solution containing boric acid and potassium iodide, a solution containing potassium iodide, and a solution containing iodine and potassium iodide and boric acid are optionally injected.

The waste liquid from the bath is stored in the waste liquid storage tank 14, and the boric acid concentrate and/or the potassium iodide concentrate are obtained in the same manner as the above process. The boric acid concentrate and/or the potassium iodide concentrate are mixed with each other, and are separately sent to the bath to be recycled.

Hereinafter, the present invention will be described in more detail by way of examples, but the invention is not limited thereto. Further, the transmittances and the evaluation of the degree of polarization shown in the examples were carried out as follows.

The transmittance of the polarizing film obtained by one piece measurement is Ts, and the transmittance of the two polarizing films when they are overlapped in the absorption axis direction is the parallel bit transmittance Tp, so that the absorption axes of the two polarizing films are overlapped. The time transmittance is the cross position transmittance Tc.

The transmittance T is obtained in the wavelength range of 380 to 780 nm, and the spectral transmittance τ λ of the predetermined wavelength interval d λ (this is 10 nm) is obtained, and is calculated by the following formula (1). In the formula, P λ represents the spectral distribution of the standard light (C light source), and y λ represents the color relationship of the 2 degree field of view.

The spectral transmittance τ λ was measured by a spectrophotometer ["U-4100" manufactured by Hitachi, Ltd.]. The degree of polarization Py is obtained from the parallel position transmittance Tp and the intersection transmittance Tc by the following formula (2).

Py={(Tp-Tc)/(Tp+Tc)} ^1/2 ×100 (2)

The hue system phase JIS Z8729 is used as a reference, and is obtained by a ^* , b ^{* of the} Commission Internationale de 1' Eclairage (abbreviated as CIE).

[Example 1]

Iodine amount is 16 g / l, boron amount is 5.4 g / l, potassium amount is 4.9 g / l, TOC is 0.01 g / l, pH 5.2 polarized film manufacturing waste liquid 5.71 by electrodialysis device (stock company Astom The system, Asilyza-S3 type) was used as a concentrate for 1 hour of water and dialysis was carried out for 3 hours at a constant voltage of 10V. Further, the membrane area of this electrodialysis unit was 0.055 m ² . ACS-8T (manufactured by Astom Co., Ltd.) was used for the anion exchange membrane. K501-SB (manufactured by Astom Co., Ltd.) was used for the cation exchange membrane. As a result, the iodine content of the concentrated solution after electrodialysis was 87 g/l, the amount of boron was 1.0 g/l, the potassium was 26.7 g/l, the TOC was 0 g/l, the iodine mobility was 94%, and the boron mobility was It is 1.9%. Further, the desalting liquid had an iodine content of 1.0 g/l, a boron amount of 5.3 g/l, a potassium amount of 0.3 g/l, and a TOC of 0.01 g/l.

[Embodiment 2]

1 l of desalting solution after moving iodine in Example 1 (Iodine amount is 1.0 g/l, boron amount is 5.3 g/l, potassium amount is 0.3 g/l, TOC is 0.01 g/l, and pH is 5.2) In addition, 0.026 l of 48% KOH aqueous solution was added, and the pH was made into a solution of 11 by electrodialysis apparatus (Asilyza-S3 type manufactured by the company Astom), and 0.2 l of water was used as a concentrate, and a constant voltage of 10 V was used for 3 hours. Dialysis. CBA (manufactured by Astom Co., Ltd.) was used for the anion exchange membrane, and AHA (manufactured by Astom Co., Ltd.) was used for the cation exchange membrane. As a result, the concentrated solution after electrodialysis had an iodine concentration of 4.75 g/l and a boron concentration of 25 g/l. The mobility of boron was 94%. Further, the desalting liquid had an iodine content of 0.05 g/l, a boron concentration of 0.3 g/l, and a TOC of 0.01 g/l.

A PVA (polyvinyl alcohol) film (manufactured by Clare Co., Ltd., trade name: AF-PS) having a degree of saponification of 99% or more and an average degree of polymerization of 2400 was immersed in warm water of 30 ° C for 2 minutes, and swelled. The swelled film was immersed in an aqueous solution of 0.1% of iodine (manufactured by Junsei Chemical Co., Ltd.) and 1.4% of potassium iodide recovered in Example 1 in a dye bath adjusted to 1.0%, and immersed at 30 ° C for 3 minutes. Dyeing treatment.

The dyed film was mixed with the boric acid 14.3% concentrate recovered in Example 2, and the boric acid concentrate adjusted to pH 4-7 was mixed with the 11.4% concentrate of potassium iodide from Example 1 in a 57% hydrogen iodide solution. After diluting with water, the crosslinking treatment was carried out in a crosslinking bath prepared by setting a boric acid concentration of 4% and a potassium iodide concentration of 5%, and immersing at 50 ° C for 3 minutes at a magnification of 5 times. Further, the film stretched in the crosslinking bath was washed in a washing bath placed in a washing water of 30 ° C for 30 seconds, and after washing, it was dried at 70 ° C for 2 minutes to obtain a polarizing film.

The polarizing film obtained by drying and the alkali-treated triacetone cellulose film (trade name: TD-80U, manufactured by Fuji Photo Film Co., Ltd.) were laminated with a polyethylene-based adhesive to obtain a polarizing plate.

[Example 4]

Hereinafter, a PVA (polyvinyl alcohol) film (manufactured by ClareCI Co., Ltd., trade name: VF-PS) having a degree of saponification of 99% or more and an average degree of polymerization of 2400 was immersed in warm water of 30 ° C for 2 minutes, and swelling treatment was carried out as Comparative Example 1. . The swelled film was adjusted to 0.1% of iodine (manufactured by Junsei Chemical Co., Ltd.), and immersed in a dye bath of 1.0% of potassium iodide (manufactured by Junsei Chemical Co., Ltd.) at 30 ° C for 3 minutes to carry out dyeing treatment. The film obtained by the dyeing was subjected to a stretching treatment at a ratio of 5% of boric acid (manufactured by Societa Chemica Larderello s.p.a.) and 50% of potassium iodide (manufactured by Junsei Chemical Co., Ltd.) in a 50° C. cross-linking bath at a magnification of 5 times.

The film stretched in the crosslinking bath was washed in a washing bath placed in a washing water of 30° C. for 30 seconds, and after washing, it was dried at 70° C. for 2 minutes to obtain a polarizing film.

The iodine, potassium iodide, and boric acid used were industrial reagents, and processing conditions were the same as in Example 1 to prepare a polarizing film.

The polarizing film obtained by drying and the alkali-treated triacetyl cellulose film (manufactured by Fuji Photo Film Co., Ltd., trade name: TD-80U) were laminated with a polyvinyl alcohol-based adhesive to obtain a polarizing plate.

The results of measuring the optical characteristics of the polarized light obtained in Example 3 and Comparative Example 1 by a spectrophotometer are shown in Table 1.

The s.p.c. in the table represents the monomer, parallel position, and cross position of the polarizing plate, respectively.

The polarizing plates obtained in Example 3 and Comparative Example 1 were cut into a size of 40 × 40 mm to carry out an endurance test.

In the endurance test, the polarizing plate was placed in a tester with a dry heat atmosphere of 95 ° C and a hot and humid atmosphere of 65 ° C and a relative humidity of 95%, and the monomer transmittance (Ts) and the polarizing film (Py) before and after the comparison test were performed for 506 hours. The amount of change.

The test results are shown in Tables 2 and 3.

From the above examples, the comparative examples, and Tables 1 and 2 show the use of a recycling system for producing a chemical solution using a polarizing film containing a waste liquid of iodine, potassium iodide and boron for producing a polarizing film, and the recovered potassium iodide aqueous solution and boric acid concentrated aqueous solution. It was confirmed that a polarizing film having excellent optical characteristics and durability can be produced.

1. . . Raw material recycling system

2. . . Polarized film

11. . . Dyeing bath

12. . . Cross-linking bath

13. . . Washing bath

14. . . Waste storage tank

15. . . Activated carbon tank

16, 17. . . Electrodialysis unit

20. . . Manufacturing line

Fig. 1 is a configuration diagram showing a recycling system for producing a chemical solution for a polarizing film to which the present invention is applied.

Fig. 2 is a graph showing the relationship between the pH of the solution representing the concentration on the horizontal axis and the concentration of boron in the concentration of non-dissociated boric acid (H ₃ BO ₃ ) on the vertical axis.

2. . . Polarized film

2a. . . PVA film

2b. . . PVA film

11. . . Dyeing bath

12. . . Cross-linking bath

13. . . Washing bath

14. . . Waste storage tank

15. . . Activated carbon tank

16, 17. . . Electrodialysis unit

20. . . Manufacturing line

twenty three. . . pH adjustment step

Claims (6)

A recycling system for producing a chemical solution for a polarizing film, comprising: a waste liquid storage for storing a waste liquid from a PVA (polyvinyl alcohol) film for producing a polarizing film in a solution bath containing iodine and potassium iodide The tank and the pH of the waste liquid stored in the waste liquid storage tank are adjusted to less than 7, and then the iodine component in the waste liquid is separated by electrodialysis to prepare an electrodialysis device for the potassium iodide concentrate, and In the potassium iodide concentrate of the electrodialysis device, a new iodine component is added, and the solution is adjusted by mixing, and then supplied to the recycled portion of the bath. A recycling system for producing a chemical solution for a polarizing film, which is characterized in that: a waste liquid storage tank for storing a waste liquid from a PVA (polyvinyl alcohol) film for producing a polarizing film in a bath solution containing boric acid and potassium iodide And adjusting the pH of the waste liquid stored in the waste liquid storage tank to less than 7, and then separating the iodine component in the waste liquid by electrodialysis to prepare an electrodialysis device for the potassium iodide concentrate, and the electricity In the dialysis device, the iodine desalting liquid is separated from the waste liquid, and the pH is adjusted to be 7 or more, more preferably 9 or more, and then the boron component in the desalting liquid is separated by electrodialysis to prepare a boric acid concentrate. The boron is separated and concentrated, and the pH of the boric acid concentrate from the electrodialysis device is adjusted to less than 7, and after mixing with the potassium iodide concentrate, a new potassium iodide and boric acid are added, and the solution is adjusted. Supply in the bath. A recycling system for producing a chemical solution for a polarizing film, comprising: a waste liquid storage tank for storing a waste liquid obtained by immersing a PVA (polyvinyl alcohol) film for producing a polarizing film in a bath containing potassium iodide; And adjusting the pH of the waste liquid stored in the waste liquid storage tank to less than 7, and then separating the iodine component in the waste liquid by electrodialysis to prepare an electrodialysis device for the potassium iodide concentrate, and from the electricity In the potassium iodide concentrate of the dialysis apparatus, a new potassium iodide is added, and the solution is mixed and adjusted, and then supplied to the recycled portion of the bath. A recycling system for producing a chemical solution for a polarizing film, characterized in that the waste liquid for immersing a PVA (polyvinyl alcohol) film for producing a polarizing film in a solution bath containing iodine and potassium iodide and boric acid is used for storage The liquid storage tank and the pH of the waste liquid stored in the waste liquid storage tank are adjusted to less than 7, and then the iodine component in the waste liquid is separated by electrodialysis to prepare an electrodialysis device for the potassium iodide concentrate, and In the electrodialysis apparatus, the iodine desalting liquid is separated from the waste liquid, and the pH is adjusted to be 7 or more, more preferably 9 or more, and then the boron component in the desalting liquid is separated by electrodialysis to prepare a boron separation and concentration portion of the boric acid concentrate, and adjusting the pH of the potassium iodide concentrate from the electrodialysis device and the boric acid concentrate from the boron separation and concentration portion to less than 7, and adding the potassium iodide concentrate to After the new iodine component and boric acid are mixed, the solution is adjusted and then supplied to the recycled portion of the bath. A recycling system for producing a chemical solution for a polarizing film, comprising: a waste liquid for immersing a PVA (polyvinyl alcohol) film for producing a polarizing film in a first bath of a first solution containing iodine and potassium iodide; And a waste liquid storage tank from which the waste liquid of the PVA film is immersed in the second bath containing the second solution of boric acid and potassium iodide is stored, and the pH of the waste liquid stored in the waste liquid storage tank is adjusted to less than 7, after which The iodine component in the waste liquid is separated by electrodialysis to prepare an electrodialysis device for the potassium iodide concentrate, and the desalting liquid separating the iodine component from the waste liquid in the electrodialysis device is adjusted to have a pH of 7 or more. More preferably, it is 9 or more, and then the boron component in the desalting liquid is separated by electrodialysis to prepare a boron separation and concentration portion of the boric acid concentrate, and a new potassium iodide concentrate from the electrodialysis device is added. After the iodine component is mixed, the first solution is adjusted, and then supplied to the first bath, and the pH of the boric acid concentrate from the boron separation and concentration portion is adjusted to less than 7, by adding this The potassium iodide is concentrated New liquid composition iodine and boric acid were mixed, adjusted to the second solution, this part of the supply to the recycling of a second bath. A recycling system for producing a chemical solution for a polarizing film according to claim 5, wherein the second bath is a bath in which the PVA film immersed in the first bath is immersed.