JP2006007717A - Treating method of film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of treating a film in liquid without damaging the film. <P>SOLUTION: In the treating method of the film, when the long organic polymer film is in contact with the liquid while being moved in the liquid, the film is supported in the liquid by a support without being in contact with the support and the direction is changed. Regarding the method of supporting the film by the support without being in contact with the support, the liquid is pushed out through a nozzle from the inner side of the support to make a gap between the film and the support. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for treating a long organic polymer film. More specifically, the present invention relates to a method for treating a film, which comprises using a support that supports a film in a non-contact manner and transporting an organic polymer film in a liquid without contacting the support such as a roll.

The organic polymer film is generally formed by a casting method or an extrusion method in which a polymer solution is cast on a substrate to form a film.
In the film thus formed, for example, cast solvent and the like remain in the casting method, and unreacted monomer and the like remain in the extrusion method. Therefore, these are removed by drying treatment. However, it is difficult to sufficiently remove such residues by only the drying process, and it is not advantageous in consideration of film shrinkage and processing cost due to the drying process.

  Therefore, in the film manufacturing process, a process of handling the film in a liquid may be used in order to perform cleaning or surface treatment of the film or extraction of a solvent or impurities. Treatments in the liquid include those that involve chemical reactions such as surface modification and those that use physical diffusion such as extraction, but both methods require a certain residence time, Even a short one takes several seconds, and a long one takes several tens of hours. One way to increase the treatment time in the liquid is to increase the size of the liquid tank, but it is desirable to reduce the size of the equipment in order to reduce equipment costs and operating costs.

  Further, in order to increase the cleaning efficiency of the film, it is preferable to remove the film from the base material and clean it by the casting method. In this case, when peeling the base material or the protective film, the film is transported or liquid When taking out from inside, there was a problem that wrinkles and scratches were likely to occur on the film. As a method for solving such a problem, a method in which a film is fixed to a frame or the like and liquid processing or the like is performed on a single sheet is common, but a continuous processing process is desirable in order to increase production efficiency.

  As a method for continuously transporting the film, there is a conveyor type that transports the film without applying tension, but a roll support system and an air floating system that transport the film while applying a constant tension are often used. When a film is transported in the liquid, since there is resistance of the liquid, a transport system using a roll support that applies tension is common.

  However, when a roll is used for transporting a film in the liquid, a liquid film is formed between the roll and the film, so that slip occurs between the roll and the film, and the surface of the film may be damaged. There is also a method of eliminating the slip by driving the roll at the same speed as the film conveyance speed, but the length of the organic polymer changes due to tension or swelling due to absorption of the liquid, so the same circumference is used in all sections of the liquid treatment tank. It is very difficult to keep up with speed.

  In the case of the roll support method, a method of reducing the surface roughness of the roll and making it difficult to be scratched by making a mirror finish is generally used. Because it reduces friction between the two, it becomes slippery and is not a fundamental solution.

Furthermore, when foreign matter adheres to the roll, it is transferred to the film as a scratch, so it is necessary to keep the roll surface clean at all times, but it is very difficult to manage the surface of all the rolls in the liquid.

  In order to eliminate the above problems, there is a method of passing the film through the liquid in a free state without touching the support such as a roll. However, in this method, the residence time of the film in the liquid is short. Therefore, the liquid processing efficiency is greatly reduced.

  As described above, there are various problems in transporting the film in the liquid, and it is extremely difficult to achieve both quality and productivity, particularly in films that are easily damaged or optical films that require high quality. Have difficulty.

  The subject of this invention is providing the method of processing a film continuously in a liquid, without giving a crack and a wrinkle to a film.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention extrude a liquid from a nozzle provided on a support to cause a gap between the film and the support when the film is conveyed in the liquid. As a result, the film can be supported without being in contact with the support and the residence time can be extended by meandering the film, so that it is possible to process the film with both quality and productivity. The present invention has been completed.

According to the present invention, the following film processing method is provided to solve the above-mentioned problems of the present invention.
(1) When a long organic polymer film is brought into contact with a liquid while being moved in the liquid, the organic polymer film is supported in the liquid in a non-contact state by the support, and the direction is changed. The processing method of the film.

  (2) The film processing method as described in (1) above, wherein the liquid is extruded from the inside of the support through a nozzle to form a gap between the film and the support, thereby bringing the film into a non-contact state. .

(3) The method for processing a film as described in (1) or (2) above, wherein the organic polymer film has a substrate.
(4) The method for processing a film according to any one of (1) to (3), wherein the organic polymer is a polymer having a sulfonic acid group.

According to the present invention, a film excellent in quality can be produced by a simple method without impairing productivity.
The film obtained by this invention can be used conveniently for optical films, such as a light distribution film and retardation film, and a proton conductive film.

Hereinafter, the processing method of the film which concerns on this invention is demonstrated in detail.
In the film processing method according to the present invention, a long organic polymer film is supported in a non-contact state by a support in a liquid, and the direction is changed.

The support used in the present invention is not particularly limited as long as it can support the film in a non-contact state. For example, the support has a structure capable of extruding a liquid between the support and the film from the inside of the support. Is mentioned. By extruding the liquid from the support and creating a gap between the support and the film by the pressure of the liquid, the film can be supported in a non-contact state.

  Examples of such a support include those in which the inside is a hollow rod, a nozzle is formed on the surface that supports the film, and the liquid introduced into the support is extruded through the nozzle. The nozzle shape employed here is not particularly limited as long as it can generate a gap between the support and the film, but a slit nozzle, a punching nozzle, etc. are preferable, and a plurality of nozzles may be formed. . Moreover, it is preferable that the support has a rod shape with a circular or semicircular cross section.

  In the present invention, it is preferable that the support is alternately installed up and down in a liquid treatment tank in which the film is brought into contact with the liquid. By installing in this way, the traveling direction of the film is reversed and the liquid is meandered. Therefore, the residence time for obtaining sufficient cleaning efficiency and the like can be secured, and the apparatus can be miniaturized. The number of supports can be appropriately determined depending on the residence time of the film in the liquid.

By using such a support, the film can be supported in a non-contact state in the liquid treatment tank, and an appropriate tension can be applied to the film. Therefore, since a constant tension, usually 5 to 500 N / m, preferably 10 to 300 N per 1 m of the film width, can be applied throughout the entire process from unwinding to winding, the film can be conveyed stably.

  The pressure of the liquid extruded from the support is not particularly limited as long as it can generate a gap between the support and the film, but is 1 to 500 kPa, preferably 5 to 200 kPa, more preferably 10 to 10 kPa. 100 kPa.

In addition, the liquid extruded from the support is usually the same type as the liquid in the liquid treatment tank, such as an aqueous solution or an organic solvent.
As aqueous solution, water from which impurities such as commonly used tap water, ion exchange water, distilled water and ultrapure water are removed; acids such as sulfuric acid and nitric acid and metal ions such as copper, zinc and tin are dissolved in these acids Examples of the acidic aqueous solution include alkaline aqueous solutions such as sodium hydroxide aqueous solution and potassium hydroxide aqueous solution, and alkaline aqueous solutions in which metal ions such as tin are dissolved in these alkaline aqueous solutions.

  Organic solvents include aromatic hydrocarbons such as benzene and toluene; aliphatic hydrocarbons such as hexane and heptane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; halogenated aliphatics such as dichloromethane and 1,4-dichloroethane Examples include hydrocarbons; alcohols such as methanol and ethanol; ketones such as acetone and methyl ethyl ketone; cyclic ethers such as tetrahydrofuran and dioxane; esters such as methyl acetate and ethyl acetate.

  In addition, in this invention, a suitable solution can be used with the processing method of a film, It is not limited to these. Moreover, the liquid extruded from a support body can circulate and use the liquid in a liquid processing tank, and may supply it from the outside.

In the present invention, the organic polymer that forms the film subjected to the treatment is not particularly limited as long as it can form a film. For example, polyphenylene, polyazole, polyimide, polyarylene sulfide, polysulfone, polyethersulfone in the main chain. , Polymers having a polyetherketone, a polyetheretherketone, a polybenzoxazole, a polybenzimidazole structure, and the like. Further, the polymer preferably has a sulfonic acid group, and examples thereof include perfluorosulfonic acid polymers such as Nafion (registered trademark).

  The method for producing these films is not particularly limited, and conventionally known methods such as a casting method and an extrusion method are employed. Moreover, although what is called a film form or a sheet form may be sufficient, as a film thickness, it is 1-1000 micrometers normally, Preferably it is 5-200 micrometers. However, when it has a base material, a thinner film thickness (1 μm or less) may be used.

  The film used in the present invention may have a substrate. By having the base material, wrinkles and scratches that occur when the protective film is peeled off during film unwinding or when the film is transported can be reduced. Furthermore, wrinkles and scratches caused by film shrinkage when the film is taken out from the liquid after the liquid treatment can be reduced.

  The treatment method according to the present invention is, for example, a method in which an organic polymer is dissolved in an organic solvent to form a solution, which is then cast on a substrate by casting, and the solvent is removed from a film produced by a solution casting method in which the film is formed into a film. It can use suitably for the method of removing. In this case, as the liquid filled in the liquid treatment tank and the liquid pushed out from the support, a liquid insoluble in the organic polymer and soluble in the organic solvent used for casting is used. Specifically, alcohol such as ethanol and water are used, but when the organic solvent used for casting is soluble in water, water is desirable from the viewpoint of safety and cost.

  When immersing the film in water, it is preferable that water is 10 parts by weight or more, preferably 30 parts by weight or more with respect to 1 part by weight of the film. In order to reduce the residual solvent amount of the obtained film, it is preferable to maintain a contact ratio as large as possible. In addition, it is also effective to reduce the amount of residual solvent in the film obtained by constantly supplying the water used for immersion at a constant flow rate so that the organic solvent concentration in the water is always kept below a certain level. . In order to suppress the in-plane distribution of the amount of the organic solvent remaining in the film, it is effective to homogenize the concentration of the organic solvent in the water by stirring or the like.

  The temperature of water when immersing the film in water is preferably in the range of 5 to 80 ° C. The higher the temperature, the faster the replacement rate of the organic solvent and water, but the greater the amount of water absorbed by the film, the lower the film's elastic modulus, making it impossible to transport under tension, and the surface of the film obtained after drying There is a concern that the condition will be rough. Usually, a temperature range of 10 to 60 ° C. is convenient because of the replacement speed and ease of handling.

The immersion time is usually in the range of 1 minute to 240 hours, although depending on the initial residual solvent amount, contact ratio, and treatment temperature. Preferably, it is in the range of 3 minutes to 24 hours.
Next, the present invention will be described in more detail with reference to the drawings.

  FIG. 1 shows an example of a processing apparatus used in a film processing method according to the present invention. As shown in FIG. 1, in this processing apparatus, an unwinding device 1 as means for unwinding a film to be processed, a guide roller 11 on the unwinding side, and a support provided in the liquid processing tank 2 Underwater turn bars 12a, 12b and 12c, an air knife 13, a guide roller 14 on the winding side, a dryer 15 as a drying means, and a winding device 3 as a means for winding the processed film. is doing.

The film 10 continuously fed from the unwinding device 1 is wound around the outer peripheral surfaces of the underwater turn bars 12a, 12b, and 12c installed in total in the liquid treatment tank 2 so that the traveling direction is changed. The liquid processing tank 2 is inverted and supported so as to meander. Underwater turn bar 1
Nozzles (not shown) are provided in 2a, 12b, and 12c, and liquid is extruded between each of the underwater turn bars 12a, 12b, and 12c and the film 10 so that the film is in a non-contact state. . In FIG. 1, three turn bars as the support are installed, but in the present invention, the turn bars can be appropriately changed depending on the residence time of the film in the liquid.

  The film 10 brought into contact with the liquid in the liquid treatment tank 2 is dried by the dryer 15 after the liquid adhered by the air knife 13 is removed, and is taken up by the winding device 3. In addition, while supplying the liquid into the liquid treatment tank 2 through a liquid supply pipe (not shown) and discharging the liquid from the liquid discharge pipe (not shown), the amount of liquid in the liquid treatment tank is reduced. A certain amount is set. The liquid treatment tank may be provided with two or more tanks continuously as necessary, for example, when the liquid treatment takes time, when several types of treatments are performed sequentially, or when washing is performed after the liquid treatment. .

  According to the present invention as described above, when a long organic polymer film is continuously brought into contact with the liquid while being moved in the liquid, the film can be transported without damaging the film surface. Further, since the film can be conveyed in a meandering manner in the liquid treatment tank, the residence time of the film in the liquid can be lengthened, and the processing apparatus can be downsized.

The film treated by the method of the present invention is useful for electrolyte membranes and optical parts, and can also be used for electronic / electrical parts and packaging materials. Among them, components for fuel cells, TFT-type LCDs, STN-type LCDs, display device substrates such as PDPs, light guide plates, protective films, retardation films, touch panels, transparent electrode substrates, CDs, MDs, DVDs, etc. Used for optical recording substrates and the like.
[Example]
EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples. In addition, about the obtained film, it evaluated by the following method.

[Evaluation methods]
<Residual solvent>
After 0.2 g of film was immersed in 5 g of solvent DMAc (dimethylacetamide) and left overnight, measurement was performed using a gas chromatograph (GC-14B manufactured by Shimadzu Corporation).

<Surface properties>
Judging by visual observation and optical microscope 50 times, it was classified into 3 ranks of A to C (A: non-defective product, B: acceptable product, but NG product, C: NG product) depending on the size and frequency of wrinkles and scratches.

[Production Example 1] Method for producing film before treatment <Polymer synthesis>
2,5-dichloro-4 '-(4-phenoxyphenoxybenzophenone), 4,4-dichlorobenzophenone and 2,2-bis (4-hydroxyphenyl) 1,1,1,3,3,3-hexafluoro A 4-chlorobenzoyl-terminated oligomer obtained from propane (number average molecular weight 11,200) and a copolymer obtained from number average molecular weight (50,000) were sulfonated to give a sulfonic acid equivalent of 2.08 meq / g. A sulfonated polymer was obtained.

<Cast to primary drying>
This sulfonated polymer was dissolved in a mixed solvent (weight ratio 1/1) consisting of N-methyl-2-pyrrolidone (NMP) and methanol to prepare a 15 wt% solution of the sulfonated polymer, and this was added to a PET film. The film was cast on the substrate and dried in an oven at 150 ° C. for 1 hour to obtain a film A having a thickness of 40 μm. The width of this film was 420 mm, and the amount of NMP in the film after drying was 14 parts by weight.

[Example 1] Non-contact conveyance water treatment The solvent extraction of the film A obtained in the manufacture example 1 was performed using the processing apparatus shown in FIG. The liquid treatment tank of this treatment apparatus has a size of width 0.8 m × length 0.8 m × height 1 m (immersion 0.8 m), and 400 L / h of ion-exchanged water is supplied to the tank. There are a total of three non-contact underwater turn bars in the liquid treatment tank, and the length of stay in the liquid is 3 by making the path direction of the film meandering in a non-contact manner and causing the film pass line to meander. A distance of 0.0 m is obtained. In this, film A was conveyed in a non-contact manner at a speed of 0.1 m / min, and NMP was extracted. After extraction, the film was dried with a hot air dryer at 80 ° C. for 5 minutes to obtain a film A-1. Table 1 shows the evaluation results of the film A-1 subjected to this treatment.

Comparative Example 1 Roll Transport Water Treatment Extraction was performed under the same conditions as in Example 1 except that the treatment apparatus shown in FIG. 2 was used. The difference between the apparatuses is that the rolls 22a, 22b, and 22c are used in place of the non-contact turn bars, and the rolls and the film 10 are brought into contact with each other to reverse the film. The roll is not driven. The size of the water tank, the residence length in the liquid, the transport speed of the film, etc. are all the same conditions. Table 1 shows the evaluation results of the film A-2 obtained by performing this treatment.

[Comparative Examples 2 and 3] No support The film A obtained in Production Example 1 was processed using the water tank shown in FIG. This apparatus does not have a film support such as a roll, and the film is suspended and allowed to pass through the liquid. By rotating the front and rear nip rolls 31 and 32 at the same speed, the length of the film in the liquid treatment tank 2 is kept constant without applying tension to the film 10. In this method, since there was no support, it was not possible to meander in the liquid, and the residence length in the liquid was about 1 m. Further, the film conveyance speed in this method is as shown in Table 1. Table 1 shows the evaluation results of the films A-3 and A-4 obtained by this treatment.

  As shown in Table 1, the film obtained by the treatment method of the present invention (Example 1) had no wrinkles or scratches on the surface, and the amount of residual solvent in the film was sufficiently reduced. .

It is the schematic which shows an example of the apparatus for making a film and a liquid contact by non-contact conveyance in the liquid which concerns on this invention. It is the schematic which shows an example of the apparatus for making a film and a liquid contact by roll support conveyance. It is the schematic which shows an example of the apparatus for making a film and a liquid contact by non-contact and non-tension conveyance.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Film unwinding apparatus 2 ... Liquid processing tank 3 ... Film winding apparatus 10 ... Film 11 ... Guide roller 12a, 12b, 12c ... Support body (underwater turn bar)
13 ... Air knife 14 ... Guide roller 15 ... Dryer

Claims (4)

  When bringing a long organic polymer film into contact with a liquid while moving in the liquid, the organic polymer film is supported in a non-contact state by a support in the liquid, and the direction is changed. Processing method.   2. The film processing method according to claim 1, wherein the liquid is pushed out from the inside of the support through a nozzle to form a gap between the film and the support to bring the film into a non-contact state.   The method for processing a film according to claim 1, wherein the organic polymer film has a base material.   The method for processing a film according to claim 1, wherein the organic polymer is a polymer having a sulfonic acid group.

Images