JP2001096553A - Method for evaluating support for manufacturing film by solution film forming method, support, method for manufacturing film and film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for evaluating a support for a solution film forming method for forming a surface adapted to an optical application by eliminating a surface fault with excellent flatness, a support, a method for manufacturing a film using the support and a film. SOLUTION: The method for evaluating a metal support for a solution film formation comprises the steps of casting a solution containing water for dissolving a resin in a halogen-containing solvent on the support to form a liquid film, drying the liquid film, releasing the film, removing the film, repeating the operations, and comparing surface faults of the support before and after the operations. The support, the method for manufacturing the film using the support and the film are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a solution casting film having excellent surface properties. More specifically, the present invention relates to a method for producing an optical film excellent in transparency and flatness without surface defects which can be suitably used for optical applications.

[0002]

2. Description of the Related Art Surface defects of a polymer resin film often cause various problems especially in optical films subjected to high-precision and high-performance processing, and the absence of surface defects is regarded as important in quality. ing.

[0003] Films for optical use are roughly classified into those used in a non-stretched state (for example, for use in a diffusion plate and a plastic electrode substrate) and those used in a stretched state (for a retardation film and a polarizing film). Generally, it is used as a functionalized material whose surface is precisely processed by coating treatment or various physical or chemical treatments.

[0004] For example, gas barrier processing, solvent resistance processing, electrode film forming processing, and the like are performed.

[0005] At this time, if the film has surface defects, the processed film has minute surface defects. For example, the electrode film and the gas barrier film may be broken or the film thickness may be non-uniform, resulting in non-uniform characteristics. is there. If such a surface defect is present in any one of the components, for example, a problem may occur in that the entire component is seriously damaged.

The disadvantages of the polymer resin film can be roughly classified into internal defects (inside the film) and external defects (in the surface of the film) for convenience.

(Internal Defects) In a process of manufacturing a polymer resin film or a process of applying a solution to a surface of a support to be processed to form a thin film, the prepared solution contains various foreign substances. There are many.

[0008] Dust in a solvent at the time of preparing a solution, dust mixed in a solute, or adhered to a solute (dust,
Needless to say, contamination from the atmosphere during the preparation of the solution may cause the generation of foreign matter, but thermal decomposition products, gel-like materials, and high-molecular-weight component hardly-soluble materials Microcrystals generated in the resin solution and whiskers that are hardly melted due to local molecular orientation due to high shearing force may also cause the generation of foreign matter.

[0009] Internal contaminants can be removed by using suitable dissolution conditions or by strengthening the filter.

[0010] One of the methods for eliminating internal defects is as follows.
A technique has been proposed in which the size and occurrence frequency of foreign matter are defined in the solution film formation of an optical film.

Japanese Patent Application Laid-Open No. 6-148426 describes a polycarbonate film in which the number of high-molecular-weight foreign matters having a size of 5 to 50 μm is 200 / cm 2 or less when viewed in plan. Further, a method of filtering foreign substances by using a specific filter opening has been proposed. As described above, foreign substances inside the polymer resin solution can be removed by using a filter having an appropriate opening.

(External Defects) On the other hand, as external defects of the film, there are scratches on the surface of the cast support and deposits on the surface, and scratches and deposits on the surface of the transporting roll of the film transferred and transferred. .

These drawbacks are detected as fine scratches and pushes, and fine depressions or protrusions on the film surface.

In the case of scratches on the cast support or roll surface,
By repairing the scratches by cleaning or polishing,
Dirt adhering to rolls and films can be removed by using a cleaning roll having a weakly adhesive surface in the transport system.

In the case of the solution casting method, the surface of the cast support has surface defects, and the defects may be transferred to the surface of the film, which may cause a defect. This is considered to be likely to occur when the surface of the support is transferred in a soft state containing a large amount of solvent (the state is the same as when a replica of the surface of the support is taken).

Such surface defects of the metal support surface include the surface defects that occur during the manufacture of a mirror-finished metal belt (the support is sometimes referred to as a belt or a belt support in this specification). There are surface defects (such as pinholes) and surface defects that occur when the belt is used.

Regarding the surface defect, a well-controlled one is prepared for the purpose, and the surface of the support is provided with a pinhole or the like whose size is widened to a level observed by a microscope and whose depth is regulated. In most cases, only a very small amount remains.

One of the surface defects is that, when a support is used for solution casting, it gradually develops and expands over a long period of time. There are various forms such as circular and elliptical forms, but the typical surface defect is coral-like or dendritic fine corrosion pits (pitting).
It is. The other is due to the elongation of the welding seam of the belt (which is thought to be due to repeated stress).

At the beginning of the use of the support, the surface of the support has few defects, and the defects do not matter in the formed film. The surface defects of the film (transferring the surface defects of the support belt) generated here are relatively small with a width of several tens μm or less, and the shapes thereof are round and oblong. .

However, surface defects transferred to the film may cause a problem in a long-term film-forming operation. When the surface of the cut piece of the steel belt after long-term (several years) operation is observed in detail, a surface defect that looks like a coral or a tree having a size exceeding about tens of μm may be observed. It is considered that the disadvantage of this shape was caused when a steel belt was used in film formation.

Such a surface defect in the case often occurs in a place where manganese, sulfur, aluminum, silicon, etc. are detected by elemental analysis of inclusions on the polished surface of the steel belt before use. In other words, such a surface defect becomes a starting point, and when the belt is used, slow corrosion proceeds on the mirror surface, and as a result, a surface defect mainly including a coral-like or a tree-like shape is generated, and the surface defect is reduced. It is considered that the film is transferred to a cast film to cause a surface defect of the film.

The following factors can be cited as factors presumed to cause the corrosion of the mirror surface of the steel belt. Corrosion due to trace moisture. A trace amount of water present in the atmosphere interacts with the chlorine-containing solvent to generate hydrogen chloride, and its chloride ions cause corrosion. Chlorine ions of hydrogen chloride contained in the solvent in trace amounts cause corrosion. When the polymer used is polycarbonate, a trace amount of chlorine ions contained during the synthesis of the polycarbonate causes corrosion.

That is, due to the action of the impurity element and the chlorine ion, which are susceptible to corrosion of the surface defect of the belt as described above, even if the chlorine ion is a very small amount, the corrosion progresses for a long time, and It is thought to produce coral-like or dendritic corrosion pits.

In the case where the surface defect which has been used for a long time is used as a starting point of corrosion and the corrosion (pitting corrosion) is enlarged on the surface of the support which has been used for a long time, or a new starting point of corrosion is determined on the belt surface. It is considered that the growth may occur at the crystal grain boundary portion and the like in some cases. When the depth of corrosion is small, even if these defects are transferred to the film surface, there is no problem in quality.However, these defects grow over a long period of time, and the spread is large, especially when the depth is deep. If this occurs, it becomes a surface defect of the film and becomes apparent to cause a problem.

Japanese Unexamined Patent Publication (Kokai) No. 6-1568 discloses a solution casting method for producing a film.
m is 5 or less inclusions / cm ² ,
Disclosed is a method for producing a solution casting film, wherein the number of inclusions of 100 μm or more on the support surface is 1 / cm ² or less, and the surface roughness Rt of the support is 1 μm or less. . This method is a technique for forming a smooth surface required for a magnetic recording medium to obtain a film having excellent surface properties and durability.

When this technique is applied to a method for producing a film for optical use, there is a problem that the frequency of surface defects of the support is too large under this condition.

In the case of a retardation film, which is one of the optical applications, if there is at least one optical surface defect having a size of 100 μm or more in the size of the A-4 size plate, the film has a retardation. Cannot be used as film. In addition, even when a surface defect on a smaller film surface is used for retardation, the film is stretched, so that the defect becomes a nucleus, and optical distortion having a size substantially corresponding to the stretching ratio is visually observed in the peripheral portion. Can not be used because it will be possible.

One of the causes of surface defects on the film surface is a surface defect of the belt. It has been found that this surface defect is typically caused by deformation of the weld during belt use.

The deformation of the welded portion when the belt is used is repeatedly expanded and contracted by a large number of repetitive stresses during the rotation of the belt, the mirror surface (the side where the belt contacts the film) is extended, and the anti-mirror surface (the side where the belt contacts the film). It is thought to be caused by the deformation of the opposite side) to shrink.

Before use, even if the welded portion is sufficiently polished to have a mirror surface that is not different from other surface portions, the joint portion is gradually deformed and expanded during use due to this repetition, and a minute portion is formed in this portion. It was found that a rupture occurred and transferred to the film surface.

Usually, the belt is manufactured by welding both ends of a sheet-like plate to form an endless belt. However, the above-mentioned minute tearing causes a lateral streak-like surface defect on the film surface corresponding to each rotation of the belt. It was found that they could even enter.

As described above, in the method for producing a defect-free film for optical use according to the prior art, internal defects can be sufficiently controlled and eliminated. Defects due to the transfer of surface defects on the cast support, which may be caused mainly by micro-corrosion and micro-deformation of the joint when using the belt for a long time, which may occur in the method, are still problems. It is the present situation that remains.

[0033]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a polymer resin film having excellent transparency and surface flatness which is useful for optical applications by eliminating surface defects. To provide.

In order to solve such problems, the present invention examines the relationship between the surface properties of a support and the surface properties of a film formed using this support in the production of a solution casting film. By this, in addition to providing a method of producing a solution casting film that can provide a film having excellent flatness, which was not obtained conventionally, for a long time, a cast belt that does not cause surface defects is produced before production. It provides a means for selection.

[0035]

Means for Solving the Problems The inventors of the present invention have made intensive studies on the solution casting method of a polymer resin film in order to solve the above problems, and as a result, have reached the present invention. That is, the present invention is as follows.

1. A solution containing water in which a resin is dissolved in a halogen-containing solvent is cast on a support to form a liquid film, and after the liquid film is dried, the operation of peeling and removing the film is repeated. A method for evaluating a metal support for film production by comparing the surface defects of the support in the above method.

2. As a surface defect of the support, a maximum length of 50 μm or more and a maximum depth of 5 μm or more for an area of at least 100 cm ² is 7 μm.
2. The method according to the above 1, wherein the number is compared with the number exceeding 0 μm.

3. As a surface defect of the support, for at least 100 cm ² of the surface defect, the number of the surface defect whose ratio L / D of the circumference L to the circle equivalent diameter D is 5.0 to 20 is compared. 2. The method according to 1 above.

4. The above-mentioned item 1 wherein the solution containing water in which the resin is dissolved in a halogen-containing solvent, 15 to 22% by weight, and containing 400 to 600 ppm of water is used as the solution containing water in which the resin is dissolved in the halogen-containing solvent. A method according to any one of claims 1 to 3.

5. The thickness of the formed liquid film is 500 to 6
The method according to any one of claims 1 to 4, wherein the liquid film is dried at 60 to 65 ° C for at least 20 minutes, and this operation is repeated at least 50 times.

6. The method according to any of claims 1 to 5, wherein the support to be evaluated comprises a weld.

7. A solution casting method in which a resin solution is cast on a metal support and formed into a film. A metal support used in a method for producing a film, which is selected by the method according to any one of the above 1 to 6. A support, characterized in that:

8. A solution casting method in which a resin solution is cast on a metal support and formed into a film. A metal support used in a method for producing a film, wherein the resin is dissolved in a halogen-containing solvent in an amount of 15 to 22% by weight. , 400-600pp
m is cast on the surface of the support on the side in contact with the film to be cast in production to form a liquid film, the thickness of the liquid film is set to 500 to 600 μm, After drying at ~ 65 ° C for 30 minutes, the operation of peeling and removing the film was repeated 100 times. Before and after the operation, the maximum length was 5 as a surface defect of the support.
0 μm or more and the maximum depth is 5 μm or more
A support for producing a film by a solution casting method, characterized in that the support has a property of substantially giving a result that no particles / m ² or less and a maximum length exceeding 70 μm exist.

9. A solution casting method in which a resin solution is cast onto a metal support and formed into a film.The metal support is used in a method for producing a film, and the welded portion of the metal support is formed by applying the resin to a halogen-containing solvent. A solution containing 15 to 22% by weight of water and containing 400 to 600 ppm of water is cast on the surface of the support welding portion on the side in contact with the film to be cast in production to form a liquid film, After the liquid film is dried at 60 to 65 ° C. for 30 minutes, and the operation of peeling and removing the film is repeated 100 times, before and after that, the surface defect has a maximum length as a surface defect. Is 50 μm or more, the one having a maximum depth of 5 μm or more is 5 pieces / m ² or less, and has the property of substantially giving the result that there is no one having a maximum length exceeding 70 μm. A support for producing a film by a solution casting method, characterized by comprising:

10. A solution casting method in which a resin solution is cast on a metal support and formed into a film. A metal support used in a method for producing a film, wherein the resin is dissolved in a halogen-containing solvent in an amount of 15 to 22% by weight. , 400-600p
pm of a solution containing water is cast on the surface of the support, which is in contact with the film to be cast in production, to form a liquid film. After drying at ~ 65 ° C for 30 minutes, when the operation of peeling and removing the film is repeated 100 times, before the repetition, as a surface defect of the support, the maximum length is 50 μm or more, and the maximum depth is Is less than 5 μm / m ² , the maximum length is not more than 70 μm, and the surface defect after the repetition is more than 70 μm. No, and the number of those having a maximum length of 50 μm or more and a maximum depth of 5 μm or more are the surface defects before the repetition, the maximum length is 50 μm or more, and the maximum depth is 5 μm or more. The solution casting method a film for manufacturing support, characterized in that has a property of giving a result of 1 / m ² to not become larger beyond than the number of shall substantially.

11. A solution casting method in which a resin solution is cast onto a metal support and formed into a film.The metal support is used in a method for producing a film, and the welded portion of the metal support is formed by applying the resin to a halogen-containing solvent. A solution containing 15 to 22% by weight of water and containing 400 to 600 ppm of water is cast on the surface of the support welding portion on the side in contact with the film to be cast in production to form a liquid film, The thickness is set to 500 to 600 μm, and the liquid film is heated to 60 to 65 ° C.
When the operation of peeling and removing the film is repeated 100 times after drying for 30 minutes, the surface defect before the repetition has a maximum length of 50 μm or more and a maximum depth of 5 μm or more. Is not more than 5 pieces / m ² , and there is no one having a maximum length exceeding 70 μm, and no surface defect after the repetition has a maximum length exceeding 70 μm. The number of those whose length is 50 μm or more and whose maximum depth is 5 μm or more is considered as a surface defect before the repetition,
A solution having a property of giving a result that the maximum length is not more than 1 piece / m ² than the number of pieces having a maximum length of 50 μm or more and a maximum depth of 5 μm or more. Support for film production method film production.

12. A solution casting method in which a resin solution is cast on a metal support and formed into a film. A metal support used in a method for producing a film, wherein the resin is dissolved in a halogen-containing solvent in an amount of 15 to 22% by weight. , 400-600p
pm of a solution containing water is cast on the surface of the support, which is in contact with the film to be cast in production, to form a liquid film. After drying at ~ 65 ° C for 30 minutes, when the operation of peeling and removing the film is repeated 100 times, before and after that, as the surface defects of the support, the peripheral length L of the surface defects and the circle equivalent diameter D Ratio L / D of 5.0 to 20
A support for producing a film by a solution casting method, characterized in that the support has a property of substantially giving the result that the number of the above is 0/100 cm ² or less.

13. The evaluation method according to any one of the above items 1 to 6, wherein the resin is an aromatic polycarbonate.

14. Wherein the halogen-containing solvent is mainly composed of methylene chloride.
14. The evaluation method according to any one of 6 and 13.

15. The support according to any one of the above 7 to 12, wherein the resin is an aromatic polycarbonate.

16. Wherein the halogen-containing solvent is mainly composed of methylene chloride.
16. The support according to any one of 12 and 15.

17. 16. The support according to any one of 7 to 12 or 15, wherein the halogen-containing solvent is mainly a mixture of methylene chloride and 1,3-dioxolane.

18. A method for producing a film from a solution of an aromatic polycarbonate, comprising using the support according to any one of the above items 7 to 17.

19. A polycarbonate film produced by the film production method described in the above item 18.

The above 1 .. ~ 19. The solution casting film refers to a film formed by extruding a solution containing a polymer resin and a solvent as main components onto a support from an extrusion die, drying the solvent, and removing the solvent.

In the above 9 and 11, the repeated evaluation of the “support welded portion” specifically includes a portion where the support is welded on the surface side in contact with the film to be cast. However, the evaluation is for a portion having a width of 5 cm. Hereinafter, the present invention will be described in more detail.

(Metal Support) The form of the support used for producing the solution casting film of the present invention includes a drum and an endless belt. Further, as a material of the support, iron, stainless steel (SUS), nickel, titanium, tantalum, copper, etc., and further, chromium,
Plating such as nickel or the like or surface treatment may be performed.

In the case of a belt-shaped support, the thickness is preferably 0.5 to 3 mm because good flatness is obtained. More preferably, it is 0.7 to 2 mm. More preferably, it is 1-2 mm.

As a result of the examination, to evaluate the difficulty of occurrence of corrosion of the support, the following 1. ~ 6. Was found to be superior.

The reason why the solution containing water is considered to be that corrosion is promoted by the presence of water. The concentration of the solution is preferably 100 to 1,000 ppm, and more preferably 400 to 600 ppm. It has been found desirable. If the amount is less than this range, the corrosion becomes slow, and the variation in the evaluation also increases. If the amount is more than this range, the variation in the evaluation also increases, probably because the corrosion is too fast.

The concentration of the resin is preferably 15 to 22% by weight, the thickness of the liquid film is preferably 250 to 1,000 μm, more preferably 500 to 600 μm, and the drying temperature is 4 μm.
0-80 degreeC is preferable and 60-65 degreeC is more preferable.
It was found that within these ranges, reliable corrosion evaluation data could be obtained with good reproducibility.

It has been found that the drying is preferably performed over a period of 20 minutes to 1 hour, and that the drying is preferably performed over a period of about 30 minutes in terms of reproducibility and reliability.

Further, the evaluation method according to the present invention is as described in 1.
It is found that the above operation is preferably repeated at least 50 times, and it is more preferable to repeat the operation about 100 times in terms of reproducibility and reliability.

As surface defects to be evaluated, those having a maximum length of 30 μm or more are preferably counted in selecting a support having excellent surface properties, and the maximum length is 50 μm.
It has been found that it is more desirable to evaluate those with a maximum depth of 5 μm or more and a maximum length of more than 70 μm.

Further, in the present invention, it has been found that surface defects on the surface of the support need to have a maximum length of 50 μm or more and a maximum depth of 5 μm or more of 5 defects / m ² or less. . Preferably, 5 / m ² have a maximum length of 50 μm or more and a maximum depth of 4 μm or more.
It is more preferable that the maximum length is 50 μm or more and the maximum depth is 3 μm or more is 5 pieces / m ² or less.

The maximum length is 50 μm or more and the maximum depth is 5
If it is larger than μm, the defects transferred to the cast polymer resin film may cause surface defects which are a problem in the quality of films for optical applications.

It is preferable that there is no defect on the surface of the support whose maximum length exceeds 70 μm. If the maximum length exceeds 70 μm, the surface defects transferred to the film when an optical film is formed may cause a serious problem.

Regarding the defects on the surface of the support or the support or the support, the number of the surface defects having a ratio L / D of 5.0 to 20 between the circumference L and the circle equivalent diameter D of 0 / 100c
It is preferably m ² or less were found. The surface defect is coral-like or dendritic and can be grasped to some extent by L / D. However, if the degree is large, the number of surface defects in long-term use tends to increase, probably because the belt surface is easily corroded. Is more likely to cause problems.

It is desirable from the viewpoint of production cost that any of the above-mentioned surface defects has no tendency to increase or has a small tendency to increase during long-term use.
It has been found that such a change can be estimated by comparing the surface defects before and after the evaluation method of the present invention.

These surface defects are at least one.
It has also been found appropriate to evaluate for an area of 00 cm ² .

The center line average surface roughness Ra of the surface of the support is preferably from 1 to 3 nm, more preferably from 1 to 2 nm. If it is larger than 3 nm, the surface of the film becomes rough, and the haze (haze value) of the film tends to increase, which is not preferable.

In order to obtain a support having such a surface property, it is important to use a metal material having few impurities. It is necessary to process the metal material into the shape of a support, and to sufficiently polish the surface in a clean environment to have flatness. Usually, the support for casting is stainless steel (SUS), SUS-304, SUS-304L, SU
An original plate made of S316, SUS-316L, SUS317 or the like is polished to obtain a super mirror polished plate. Especially SUS-31
6L is preferable from the viewpoint of corrosion resistance.

The flatness of the surface and the occurrence of surface defects (frequency of appearance of size, etc.) are conditions for mirror polishing, such as adjustment of the concentration of the polishing solution, the type of abrasive grains at the time of polishing, and the particle size of the abrasive grains. Various conditions of polishing and a method of removing heat generated during polishing,
It depends on the cleanliness of water at the time of cleaning and cooling the mirror surface after polishing, etc., and extremely sophisticated technology is required to create a mirror surface having virtually no defects.

(Polymer Resins) Examples of polymers include polycarbonate, polyarylate, polysulfone, polyethersulfone, aromatic polyamide, aromatic polyimide, cellulose polymers such as cellulose diacetate and cellulose triacetate, and vinyl acetate. , And the like.

The solution casting film of the present invention is preferable because the effect of the present invention is large when the polymer is an aromatic polycarbonate. For this reason, the case of a solution casting method of an optical polycarbonate film will be described below as a typical example of the polymer. Here, polycarbonate refers to a polymer obtained by reacting an aromatic dihydroxy compound with a compound capable of forming a carbonic acid bond such as phosgene and diphenyl carbonate in a solution state, a bulk state, a molten state, or the like. .

Specific examples of the aromatic dihydroxy compound include the following compounds. That is, 1,1-bis (4-hydroxy-3-t
-Butylphenynyl) propane, 2,2-bis (4-hydroxy-3-t-butylphenyl) propane, 2,2
-Bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane,
2,2-bis (4-hydroxy-3-bromophenyl)
Bis (hydroxyaryl) alkanes such as propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis ( Bis (hydroxyaryl) cycloalkanes such as 4-hydroxyphenyl) cyclohexane and 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 9,9-bis (4-hydroxyphenyl) fluorene , Fluorenes such as 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene, dihydroxyaryls such as 4,4'-dihydroxydiphenyl ether and 4,4'-dihydroxy-3,3-dimethylphenyl ether Ethers, 4,4′-dihydroxydiphenyl sulfide, 4, '- dihydroxy-3,3'
-Dihydroxyaryl sulfides such as dimethylphenyl sulfide, dihydroxyaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3'-dimethylphenyl sulfoxide, and 4,4'-dihydroxydiphenyl sulfone And dihydroxyaryl sulfones such as 4,4'-dihydroxy-3,3'-dimethylphenyl sulfone.

Of these, 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) is particularly preferably used. These aromatic dihydroxy compounds can be used alone or in combination.

In general, it is also possible to use a polycarbonate in which a part of the carbonic acid component is replaced by a terephthalic acid and / or isophthalic acid component. By using such a constituent unit as a part of the constituent component of the polycarbonate composed of bisphenol A, the properties of the polycarbonate, for example, heat resistance and solubility can be improved. The present invention can be used for such a copolymer.

(Molecular Weight of Polymer) The molecular weight of the resin material that can be used in the present invention is not particularly limited. For example, the molecular weight of aromatic polycarbonate is 20 g in a methylene chloride solution having a concentration of 0.5 g / dl. Viscosity-average molecular weight determined from viscosity measurement at a temperature of not less than 10,000, preferably from 20,000 to 120,000.

(Solvent) The halogen-containing solvent of the resin material that can be used in the present invention is not particularly limited, and commonly known halogen-containing solvents can be used.
For example, the solvent used to prepare the solution of the aromatic polycarbonate includes methylene chloride or 1,3-
Examples thereof include dioxolan, a mixture thereof, and a solvent mainly composed of these.

These solvents preferably contain as little water as possible in normal film production. When methylene chloride is used as the solvent, the water content is adjusted to 50 ppm or less, more preferably 30 ppm or less. The dehydration (drying) of the solvent can be carried out by a generally known dehydration apparatus filled with a molecular sieve.

However, when these solvents are used in the evaluation method of the present invention, it goes without saying that water may be contained as long as the concentration is within the range of the object of the present invention. That is, 15 to 22% by weight of the resin is added to the halogen-containing solvent.
"Water" in a solution containing 400 to 600 ppm of water that has been dissolved may be one that has been independently added to a halogen-containing solvent or one that has been contained in a halogen-containing solvent from the beginning, It may be composed of both.

The water content in the resin-containing solution for casting in the ordinary solution casting method is preferably as low as possible in order to prevent the belt from being corroded. It is difficult to achieve zero due to the water content, and when the polycarbonate is dissolved in methylene chloride, the concentration is desirably adjusted between 10 and 300 ppm.

(Solution film formation) A solution in which an aromatic polycarbonate is dissolved in the above-mentioned solvent is prepared. This solution is usually adjusted so that the polycarbonate content is 15 to 35% by weight. The resin solution prepared as described above is extruded from an extrusion die onto a metal support, and cast on the support.

(Drying) The cast liquid film is divided into several sections and drying conditions for each section (hot air temperature, wind speed, etc.)
Dry using an oven that can be changed. The liquid film immediately after being cast on the support is dried so that the surface is not disturbed as much as possible and so-called leveling unevenness is not generated. The method of heating employs a method of drying the cast liquid film with hot air in order to increase the drying efficiency, or a method of heating the anti-liquid film surface of the belt with a heat medium. It is preferable to use hot air for ease of handling operation.

The temperature of the belt surface immediately after casting and the temperature of the atmosphere must not be higher than the boiling point of the solvent in which the polymer is dissolved. Raising the temperature of the liquid film above the boiling point results in bubbles being generated in the film due to bumping of the solvent. If the solvent is methylene chloride, its temperature is 40 ° C
The temperature is preferably set to 30 ° C. or lower.

Further, when the solvent is methylene chloride, the temperature is set at 40 ° C. to 45 ° C. in the next section, and the liquid film is dried until the methylene chloride concentration in the liquid film becomes about 35% by weight so that the liquid film is not deformed. It is usual to do.

When the solvent is methylene chloride, the temperature is 45 to 50 ° C. in the third section, and the amount of the solvent in the film is 25 ° C.
Usually, it is about weight%.

In the fourth section, the drying temperature is 50 to 55 ° C., and the amount of solvent in the film at this time is about 2
Usually it is 0% by weight. In the fifth section, it is usual to cool to 15 ° C. and strip the film from the support.

In the present invention, during the belt film forming operation,
Do not raise the ambient temperature above 60 ° C. in all compartments. More preferably, the temperature is 55 ° C. or lower.

In the cast drying, the atmosphere temperature is controlled so as not to exceed the above-mentioned temperature. That is, when the solvent is methylene chloride, the temperature of the metal support is set to 60
Do not raise the temperature above ℃. If it is above this temperature,
When the belt is used for a long period of time such as several years, minute coral-like or dendritic corrosion holes are easily generated on the mirror surface of the belt, which is not preferable.

When the belt support is run, the necessary tension applied to the belt support is determined by the running mechanism of the belt, but the minimum value necessary to run the belt in a state where it is not meandering and is kept flat. It is better not to raise more than necessary. Further, in order to suppress the deformation of the belt joint due to the repeated bending stress on the pulley on the belt, the diameter of the pulley around which the belt is wound is 100 mm.
0 mm or more, more preferably 150 mm or more.
0 mm or more.

If the tension applied to the belt is too large or the diameter of the belt is too small, the belt support is likely to be deformed at the joining portion, and the mirror surface portion will have a disconnected surface defect within a long period of time. Is not preferred because it is transferred to the cast film and causes surface defects.

(Post-Drying) Then, the film is post-dried and then further dried for use without stretching or use after stretching. At this time, the film is generally dried while controlling the optical characteristics (refractive index) of the film.

The drying of the film is performed by appropriately combining known drying methods such as a pin tenter of a type in which both ends in the width direction of the film are gripped and conveyed, a roll hanging type dryer and an air floating type dryer. Characteristics can be controlled.

The thus obtained film is wound up to obtain an aromatic polycarbonate film for optical use.

Although the thickness of the film to be formed is not limited, it is generally 300 μm or less, preferably 20 μm to 200 μm.
μm. Particularly in the case of a thin film, the surface defects of the support may be transferred to the film and deteriorate the surface properties not only on the support contact surface but also on the support non-contact surface where the film did not contact. It is more preferable to use one having few surface defects.

(Surface Defect Evaluation of Front Support of Surface Support of Surface Support) The surface defect of the support of the present invention was evaluated by the following method. The environmental temperature at which the film is prepared and processed for evaluating the surface defect of the support is preferably 20 to 25 ° C., and the humidity is preferably 50 to 65% RH.

The concentration of the resin dissolved in the halogen-containing solvent is 1
5 to 22% by weight is preferable, and the water content is 100 to 1,0%.
00 ppm is appropriate, especially 400-600p
pm is preferred. The thickness of the liquid film formed by casting is 250
１，1,000 μm is preferable, and 500-600 μm is more preferable. The drying of the liquid film is preferably at 40 to 80C, more preferably at 60 to 65C. The drying time is preferably within one hour, more preferably about 30 minutes. As the surface defects to be evaluated, it is preferable to count those having a maximum length of 30 μm or more in selecting a support having excellent surface properties, and those having a maximum length of 50 μm or more and a maximum depth of 5 μm or more. It is more desirable to evaluate those having a maximum length exceeding 70 μm.

According to the study by the inventors of the present invention, the disadvantages of the film surface in actual film production are that the surface of the support may be manifested for the first time in long-term production exceeding one year. It has been clarified that the surface defect of the support due to the deterioration with time exists as a large factor. Then, such a defect of the support surface that may become apparent only after long-term use can be found in a short time by the evaluation according to the present invention, and a support having excellent properties is selected in advance. It can be used.

[0101]

An example according to the present invention will be described below. The measurement and evaluation of the effects of the present invention were performed by the following methods.

(1) Accelerated deterioration test of the support. A test piece (support sample) was cut from the mirror-polished belt support to the size of the A-4 plate. A solution obtained by adding water to a solution of a polymer resin was applied to a support sample, and an acceleration test was performed.

The conditions of the accelerated test were as follows. 1) A solution in which an aromatic polycarbonate is dissolved in a methylene chloride solvent at 15 to 22% by weight is used. 2) The amount of water in the solution applied to the support sample was 400
To 600 ppm. 3) The thickness of the liquid film applied to the support sample is 500 to 6
00 μm. 4) The support sample coated with the solution was heated at 60-65 ° C. for 3 hours.
Dry for 0 minutes. Thereafter, the film is peeled off and removed, and the solution is applied again. This is repeated 100 times.

(2) Surface Defects of the Support The surface defects that were present when the belt support was prepared, and the surface defects that were generated or enlarged when the support was used were examined using the support samples.

The surface of the support sample was observed with a metallographic microscope, and surface defects such as islands were examined. FIG. 1 shows an example of a surface defect. In FIG. 1, the number 1 represents the maximum length of a surface defect. Surface defects caused by impurities in the support sample material, scratches generated during polishing, and the like were also included in this.

When it is difficult or impossible to directly observe the surface of the support sample with a metallographic microscope, a replica was taken from the surface of the support sample and observed with another microscope such as a transmission microscope. The replica was based on a method using cellulose acetate film and ethyl acetate. It was previously confirmed that the direct observation result of the support sample surface and the observation by the replica method were in good agreement.

The surface defects were counted for those having a maximum length of 30 μm or more, and those having a maximum length of 50 μm or more and a maximum depth (the maximum height in the case of the replica method) of 5 μm or more and a maximum length of 70 μm were determined. Counted as exceeding.

The maximum length was determined as the distance between the most distant points on the surface defect portion as indicated by No. 1 in FIG. The maximum depth of the surface defect (the maximum height in the case of the replica method) was measured using a laser microscope VF-7500 manufactured by Keyence Corporation.

The number of surface defects The number of surface defects was determined by observing 100 cm ² of each of 100 randomly selected sample surfaces of the support with a metallurgical microscope and summing the results to the surface per 1 m ^2. The number of defects was taken.

However, for the support sample welded parts according to 9 and 11 above, measurement was performed on all of the 5 cm wide portions including the welded portions of the support sample on the surface side in contact with the film to be cast. Done, 1
It was converted to the number per m ² . In this case, the converted value was obtained as an integer by rounding off the first digit after the decimal point.

Independently of these, a factor of 1000
10cm each of 10 places photographed at the rate ^TwoMetal micrograph of
The part was measured using an image analyzer and the maximum length was 30 μm
For the above surface defects, the ratio of the circumference L to the circle equivalent diameter D
L / D of 5.0 to 20 corresponds to a surface defect.
Was. Here, the circle equivalent diameter D is defined as the area of the surface defect.
D = (4S / π)^0.5But there is something I stopped.

(3) Measurement of the center line average surface roughness (Ra) of the support sample The center line average surface roughness (Ra) is a value defined by JIS-B0601, and the numerical value in the present specification is:
Contact surface roughness meter from Kosaka Laboratory Co., Ltd.
der, SE-30C). The measurement conditions were as follows. Stylus tip radius: 2 μm Measurement pressure: 30 mg Cut-off: 0.08 mm Measurement length: 1.0 mm The data was repeatedly measured five times for the same material, and the measured values (up to the fourth decimal place in μm units) Value), the largest value was removed, and the average value of the remaining four data was rounded off to the fifth decimal place and displayed to the fourth decimal place in nm.

(4) Measurement of Water Content in Solution The water content was measured according to the Karl Fischer method. The measuring instrument used was an automatic moisture meter KF-07 manufactured by Mitsubishi Chemical Corporation.
In the measurement, since the viscosity of the solution was so high that the amount of the solution could not be directly measured and charged into the measurement container, the following procedure was used. That is, a certain amount of the solution was placed in an Erlenmeyer flask, and a certain amount of ethanol having a known water content was added thereto, followed by thorough stirring to precipitate the polymer. The water content of this mixed liquid (supernatant) was measured. The water content of the solution was calculated from the measurement data.

(5) Measurement of Surface Defects Produced on Film Surface A-4 plate was prepared as a sample film. The surface defect was performed in the same manner as in the case of the replica method in the above (2).

Example 1 A super-mirror polished product made of SUS-316L and having a thickness of 1.1 mm as a belt support and a plate (ultra-mirror surface) before welding the belt support to an endless belt A plurality of samples cut out from the polished material) to the A-4 size were prepared. The ultra-polished plate was welded to form a belt support, and the welded portion was subjected to ultra-mirror polishing again.

(Evaluation of Sample Section Before Accelerated Degradation Test) A section obtained from the A-4 size sample was subjected to a test. The surface roughness Ra of the surface of the section was 1.5 nm. The maximum length of the surface defects of the section is 50 μm or more and 70 μm
m / m ² and a maximum depth of 5 μm or more was 1 piece / m ² , and none of the surface defects had a maximum length exceeding 70 μm. The number of L / D with 5.0 to 20 is 0/10
It was 0 cm ² . The section was subjected to an accelerated deterioration test as follows.

(Evaluation of Accelerated Deterioration of Sample Section) An aromatic polycarbonate resin (trade name, Panlite (registered trademark) grade C-1400QJ, manufactured by Teijin Chemicals Ltd.) and a viscosity average molecular weight of 38,000 were dissolved in a methylene chloride solvent. Then, an 18% by weight solution was prepared. This solution is 55
It contained 0 ppm of water. A liquid film was applied to the section to have a thickness of 550 μm. The solution and the section were dried in an air oven at 63 ° C. for 30 minutes. Thereafter, the film and the section were taken out at room temperature, the film was peeled off and removed, and the solution was applied again. This was repeated 100 times. The newly generated or enlarged surface defects have a maximum length of 50 μm or more and 70 μm or less and a maximum depth of 5 μm or more 1 / m ² , and the maximum length of the surface defects is 70 μm / m ² .
None of them exceeded μm. L / D from 5.0 to 20
Was 0/100 cm ² .

(Application of Belt Support Belt Support to Film Production) Aromatic polycarbonate resin pellets (trade name “Panlite (registered trademark) grade C-1400QJ” manufactured by Teijin Chemicals Ltd.), viscosity average molecular weight 3
The 8,000 was dried with hot air at 120 ° C for 16 hours and then cooled to 30 ° C with dehumidified air.

The aromatic polycarbonate resin pellets were dissolved in a methylene chloride solvent to prepare an 18% by weight solution. The water content of the solution thus obtained is 270
ppm. This solution was passed through a filter to remove foreign substances. Further, the temperature of the solution was adjusted to 15 ± 0.5 ° C., and the solution was introduced into a coat hanger die having a width of 500 mm, and subsequently cast as a liquid film of about 560 μm on the support. The temperature (surface temperature) of the support immediately before the start of casting was set to 9 ° C. The cast film was dried as follows.

(First Section) In the initial stage of drying, the back surface of the support is heated by blowing hot air at 30 ° C., and the film is kept at an ambient temperature of 20 ° C. so that deformation of the film (defective leveling) does not occur. Carefully dried.

(Second Section) Next, the liquid film was dried by blowing hot air until the ambient temperature was 45 ° C. and the methylene chloride concentration in the liquid film was about 35% by weight. (Third section) Then, the film was dried at a temperature of 50 ° C. by blowing hot air, and the solvent concentration in the film was reduced to 25% by weight.
And

(Fourth Section) Further, drying was performed at an ambient temperature of 55 ° C. At this time, the solvent concentration in the film was 20% by weight.

(Fifth Section) The above film was cooled together with the support in air at 15 ° C. The solvent concentration in the film at the end of this step was 18% by weight.

Next, the film was peeled from the support. The peeled film was further transported to a step of drying with a pin tenter type dryer. afterwards,
Subsequently, the film was passed through a drier of a roll suspension type and an air-floating heating device, and wound up by a winder.

When the belt support is operated (used), the temperature of the atmosphere in which the belt is placed is set to 60 in any section.
° C or less.

When the belt support is run, the bell
2Kg / mm ^TwoAnd cast
The oven dew point was controlled to be 5 ° C.

The film thus obtained according to the present invention was examined for characteristic values. The film was excellent in optical transparency and excellent in optical use.

Thus, the film forming operation was performed for three years. The average availability during that time was 80%.

During this period, the surface defects generated on the film surface when transferred in correspondence with the surface defects of the portion other than the welded portion of the belt support every six months were examined.

As a result, as a result, as for these films, the number of surface defects occurring on the film surface is one having a maximum length of 50 μm or more and 70 μm or less and a maximum height of 5 μm or more. Pieces / m ² ,
Further, there was no one having a maximum length exceeding 70 μm.
Also, the number of L / Ds having a value of 5.0 to 20 is 0/10
It was 0 cm ² .

As described above, the surface defects generated on the film surface did not show a tendency to increase, and no coral or dendritic surface defects caused by the deterioration of the belt could be found.

That is, it was found that the belt support of this example did not increase the surface defects even when actually used for the film forming operation.

Comparative Example and Example 1 A belt support and a sample were prepared in the same manner as in Example 1. However, the belt support was not subjected to the ultra-mirror polishing treatment, but to a slightly inferior mirror polishing treatment. The mirror-polished plate was welded so as to have the shape of a belt support, and the welded portion was mirror-polished again.

(Evaluation of sample section before accelerated deterioration test) A section obtained from the A-4 size sample was subjected to a test. The surface roughness Ra of the surface of the section was 3.5 nm. The maximum length of the surface defects of the section is 50 μm or more and 70 μm
m and a maximum depth of 5 μm or more were 10 defects / m ² , and those of the surface defects having a maximum length exceeding 70 μm were 3 defects / m ² . In addition, the number of samples having an L / D of 5.0 to 20 was 3/100 cm ² .

(Evaluation of accelerated deterioration of sample section) The sample section was subjected to an accelerated deterioration test in the same manner as in Example 1. 13 newly generated or enlarged surface defects having a maximum length of 50 μm or more and 70 μm or less and a maximum depth of 5 μm or more are 13 pieces / m ² , and the maximum length of the surface defects is 70 μm
The number exceeding 5 was 5 pieces / m ² . In addition, the number of samples having an L / D of 5.0 to 20 was 5/100 cm ² .

(Application of belt support to film production)
A film was produced in the same manner as in Example 1 except that the above-mentioned belt support was used instead of the belt support used in Example 1.

As a result, in these films, the number of surface defects generated on the film surface to be transferred corresponding to the surface defects of the portion other than the welded portion of the belt support initially has a maximum length of 50 μm or more. in 70 [mu] m or less, and the maximum height is 5μm or more is 11 / m ^2, was also present are three / m ² that the maximum length exceeds 70 [mu] m. In addition, the number of samples having an L / D of 5.0 to 20 was 4/100 cm ² .

The values after three years of production (operating rate: 80%) are 15 pieces / m ² whose maximum length is 50 μm or more and 70 μm or less, and whose maximum height is 5 μm or more. There are 4 / m ² having a maximum length exceeding 70 μm, and the number of those having an L / D of 5.0 to 20 is 6/1.
00 cm ² and showed a tendency to gradually increase.

[Example 2] A plate (ultra-mirror polished) before welding the belt support of Example 1 into an endless belt was cut in the width direction of the plate to obtain two samples. These two samples were welded in the same manner as in the case of producing the above-mentioned ultra-mirror polished product belt support, and subjected to ultra-mirror polishing to produce a welded sample.

(Evaluation of weld sample before accelerated deterioration test) The weld sample was subjected to a test. Surface roughness Ra
Was 1.5 nm. The maximum length of the surface defects of this welding sample is 50 μm or more and 70 μm or less and the maximum depth is 5 μm
The above ones were 2 pieces / m ² , and none of the surface defects had a maximum length exceeding 70 μm. The number of samples having an L / D of 5.0 to 20 was 0/100 cm ² . Also,
The weld sample was subjected to an accelerated aging test as follows.

(Evaluation of Accelerated Deterioration of Weld Sample) The weld sample was subjected to accelerated deterioration evaluation in the same manner as in Example 1. Newly generated or enlarged surface defects had a maximum length of 50 μm or more and 70 μm or less and a maximum depth of 5 μm or more 2 pieces / m ² , and none of the surface defects had a maximum length exceeding 70 μm. The number of samples having an L / D of 5.0 to 20 was 0/100 cm ² .

(Application of belt support to film production)
In the film production performed in Example 1, surface defects on the cast film transferred corresponding to the surface defects of the welded portion of the belt support were examined approximately every six months. As a result, in these films, the number of surface defects generated on the film surface is as follows: the maximum length is 50 μm or more, 70 μm or more.
m or less, the maximum height of which was 5 μm or more was 1 piece / m ² , and the maximum length exceeded 70 μm. Further, the number of samples having an L / D of 5.0 to 20 was 0/100 cm ² . As described above, the surface defects generated on the film surface did not show an increasing tendency, and no coral or dendritic surface defects generated due to the deterioration of the belt could be found. That is, it was found that the belt support of this example did not increase the surface defects even when actually used for the film forming operation.

Comparative Example and Example 2 A plate (mirror-polished) before welding the belt support of Comparative Example 1 into an endless belt was cut in the width direction of the plate to obtain two samples. These two samples were welded and mirror-polished in the same manner as in the preparation of the above-mentioned mirror-polished product belt support to prepare a welded sample.

(Evaluation of weld sample before accelerated deterioration test) The weld sample was subjected to a test. Surface roughness Ra
Was 3.5 nm. The maximum length of the surface defects of this welding sample is 50 μm or more and 70 μm or less and the maximum depth is 5 μm
The number of defects was 8 / m ² , and the number of surface defects having a maximum length exceeding 70 μm was 2 / m ² . Also, L
The number of / D of 5.0 to 20 is 3/100 cm ²
Met.

(Evaluation of accelerated deterioration of welded sample) The welded sample was subjected to an accelerated deterioration test in the same manner as in Example 1. Newly generated or enlarged surface defects have a maximum length of 50 μm or more and 70 μm or less and a maximum depth of 5 μm or more 10 pieces / m ² , and the maximum length of the surface defects is 70 μm
The number exceeding 5 was 5 pieces / m ² . In addition, the number of samples having an L / D of 5.0 to 20 was 6/100 cm ² .

(Application of belt support to film production)
In the film production performed in Comparative Example 1, the surface defects on the cast film transferred corresponding to the surface defects of the welded portion of the belt support were examined approximately every six months. As a result, in these films, the number of surface imperfections that occur on the film surface initially has a maximum length of 50
7 / m ² had a maximum height of 5 μm or more and 7 μm or more, and 1 / m ² had a maximum length exceeding 70 μm. In addition, the number of samples having an L / D of 5.0 to 20 was 1/100 cm ² . After three years of production (operating rate 80%), the maximum length is 50 μm or more and 70 μm or less, the maximum height is 5 μm or more is 9 pieces / m ² , and the maximum length is There are 5 particles / m ² exceeding 70 μm, and L /
The number of samples having a D of 5.0 to 20 was 7/100 cm ² , and showed a tendency to gradually increase.

[0147]

According to the present invention, the solution casting film produced by using the support having the surface characteristics of the present invention is excellent in the flatness of the surface and extremely excellent in eliminating the surface defects. A surface suitable for optical use as an aromatic polycarbonate film can be formed.
Therefore, the workability of the film is significantly improved even when the film surface is made highly functional by applying various materials or providing a metal thin film.

[Brief description of the drawings]

FIG. 1 shows an example of a surface defect according to the present invention.

[Explanation of symbols]

 1. Maximum length

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] November 11, 1999 (1999.11.
11)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 2

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name]

[Correction method] Change

[Correction contents]

[0068] Further, the drawback of the surface supporting region thereof, that the number of ones from the ratio L / D of the circumferential length L and the circle equivalent diameter D of the surface defect is 5.0 20 is 0/100 cm ² or less Was found to be preferable. The surface defect is coral-like or dendritic and can be grasped to some extent by L / D. However, if the degree is large, the number of surface defects in long-term use tends to increase, probably because the belt surface is easily corroded. Is more likely to cause problems.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0072

[Correction method] Change

[Correction contents]

In order to obtain a support having such a surface property, it is important to use a metal material having few impurities. It is necessary to process the metal material into the shape of a support, and to sufficiently polish the surface in a clean environment to have flatness. Usually, the support for casting is stainless steel (SUS), SUS-304, SUS-304L, SU
An original plate made of S - 316, SUS-316L, SUS - 317, or the like is polished to obtain a super mirror polished plate. Especially SUS-
316L is preferable from the viewpoint of corrosion resistance.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0093

[Correction method] Change

[Correction contents]

[0093] When the diameter of the tension hook wound too large to be applied to the belt is too small, easily deformed belt support at its junction, <br/> tear on the mirror surface portion of the long-term This is undesirable because it causes surface imperfections which are transferred to the cast film and cause surface imperfections.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0098

[Correction method] Change

[Correction contents]

(Evaluation of Surface Defect of Support) Evaluation of the surface defect of the support of the present invention was carried out by the following method. The environmental temperature at which the film is prepared and processed for evaluating the surface defect of the support is 2
The temperature is preferably 0 to 25 ° C , and the humidity is preferably 50 to 65% RH.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name]

[Correction method] Change

[Correction contents]

The number of surface defects was 100 cm for each of 100 randomly selected surfaces of the support sample.
² was observed with a metallurgical microscope, and the total
The number of surface defects per m ² was taken.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0112

[Correction method] Change

[Correction contents]

(3) Measurement of the center line average surface roughness (Ra) of the support sample The center line average surface roughness (Ra) is a value defined by JIS-B0601, and the numerical value in the present specification is:
Contact surface roughness meter from Kosaka Laboratory Co., Ltd.
der, SE-30C). The measurement conditions were as follows. Stylus tip radius: pressure 2μm measurement: 30 mg Cutoff: 0.08 mm Measuring length: 1.0 mm data, repeated 5 times for the same specimen were measured, until the fourth digit below the decimal point by the measured value ([mu] m units ), The largest value was removed, and the average value of the remaining four data was rounded off to the fifth decimal place and displayed to the fourth decimal place in nm.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name]

[Correction method] Change

[Correction contents]

(Application of belt support to film production)
Aromatic polycarbonate resin pellets (Teijin Chemical Co., Ltd.)
Product name "PANLITE (registered trademark) Grade C-14"
00QJ "), a viscosity average molecular weight of 38,000 at 12 ° C
For 16 hours and then cooled to 30 ° C. with dehumidified air.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Chieko Miyoshi 77, Kitayoshida-cho, Matsuyama-shi, Ehime Teijin Co., Ltd.Matsuyama Office (72) Inventor Minoru Hirota 77, Kitayoshida-cho, Matsuyama-shi, Ehime Teijin Co., Ltd. Matsuyama Office F-term (reference) 4F205 AA28 AB19 AB21 AC05 AG01 AH73 AJ02 AJ08 AM14 AP20 AR06 AR12 GA07 GB02 GC07 GE22 GE24 GF01 GF23 GF24 GF13 GN13 GN19 GN22 GN25 GN28 GN29 GW39

Claims (19)

[Claims] 1. An operation of casting a solution containing water, in which a resin is dissolved in a halogen-containing solvent, on a support to form a liquid film, drying the liquid film, and peeling off the film to remove the film. And a method of evaluating a metal support for producing a film by a solution casting method in which surface defects of the support are compared before and after. 2. The surface defects of the support include those having a maximum length of at least 50 μm and a maximum depth of 5 μm or more and a maximum length of more than 70 μm for an area of at least 100 cm ^2. 2. The method of claim 1, wherein 3. As a surface defect of the support, at least an area of 100 cm ² , the peripheral length L of the surface defect.
The method according to claim 1, wherein the number L / D of the ratio of the circle diameter D to the circle equivalent diameter D is 5.0 to 20. 4. A water-containing solution in which the resin is dissolved in a halogen-containing solvent, wherein the resin is mixed with
4. The method according to claim 1, wherein a solution containing 400 to 600 ppm of water in which 22% by weight is dissolved is used. 5. The thickness of the formed liquid film is from 500 to 600.
The method according to any one of claims 1 to 4, wherein the liquid film is dried at 60 to 65 ° C for at least 20 minutes, and this operation is repeated at least 50 times. 6. The method according to claim 1, wherein the support to be evaluated comprises a weld. 7. A metal support used in a method for producing a film by a solution casting method in which a resin solution is cast on a metal support and formed into a film, wherein the metal support is used in any one of claims 1 to 6. A support characterized in that it is selected by the method of (1). 8. A metal support for use in a method for producing a film, wherein the resin solution is cast on a metal support and formed into a film. A solution containing 400 to 600 ppm of water, in which the weight is dissolved, is cast on the surface of the support, which is in contact with the film to be cast in production, to form a liquid film. 600 μm, and the liquid film
After drying at 0 to 65 ° C. for 30 minutes, the operation of peeling and removing the film was repeated 100 times. Before and after the operation, the maximum length was 50 μm as a surface defect of the support.
m or more, and the maximum depth is 5 μm or more
A support for producing a film by a solution casting method, characterized in that the support has a property of substantially giving a result that there is no m ² or less and a maximum length exceeding 70 μm does not exist. 9. A metal support used in a method for producing a film by a solution casting method in which a resin solution is cast on a metal support and formed into a film, wherein the welded portion of the metal support is:
A solution containing 15 to 22% by weight of the resin dissolved in a halogen-containing solvent and containing 400 to 600 ppm of water is cast on the surface of the support-welded portion on the side in contact with the film to be cast in production. Liquid film is formed, and its thickness is 5
100 to 600 μm, and the liquid film is heated at 60 to 65 ° C. for 30 minutes.
After drying for 1 minute, remove the film and remove
When the repetition was performed 00 times, before and after that, as a surface defect, the maximum length was 50 μm or more and the maximum depth was 5 μm.
a film having a size of not less than 5 μm / m ² and a property of substantially giving a result that no one having a maximum length exceeding 70 μm is present. Support. 10. A metal support for use in a method for producing a film, wherein the resin solution is cast on a metal support and formed into a film. 400-600 ppm dissolved by weight
A solution containing water is cast on the surface of the support, which is in contact with the film to be cast in production, to form a liquid film, the thickness of the liquid film is set to 500 to 600 μm, and the liquid film is set to 60 to 600 μm. After drying at 65 ° C. for 30 minutes, when the operation of peeling and removing the film is repeated 100 times, before the repetition, as a surface defect of the support, the maximum length is 50 μm or more and the maximum depth is 50 μm or more. Those having 5 μm or more are 5 pieces / m ² or less, and those having a maximum length exceeding 70 μm are not present, and those having a maximum length exceeding 70 μm are present as surface defects after the repetition. And the maximum length is 50 μm or more and the maximum depth is 5
The number of those having a maximum length of 50 μm or more and the maximum depth of 5 μm or more as the surface defect before the repetition does not exceed 1 / m ^2. Having the property of substantially giving the result. 11. A metal support used in a method for producing a film by a solution casting method in which a resin solution is cast on a metal support and formed into a film, wherein the metal support welding portion has a halogen-containing property. A solution containing 400 to 600 ppm of water obtained by dissolving the resin in a solvent in an amount of 15 to 22% by weight is cast on the surface of the support-welded portion on the side in contact with the film to be cast in production. When a film is formed, the thickness thereof is set to 500 to 600 μm, and after the liquid film is dried at 60 to 65 ° C. for 30 minutes, and the operation of peeling and removing the film is repeated 100 times, before the repetition, As surface defects, there are 5 / m ² or less having a maximum length of 50 μm or more and a maximum depth of 5 μm or more, and no one having a maximum length of more than 70 μm. smell As a surface defect, there is no thing that the maximum length exceeds 70 [mu] m, and the maximum length is 50μm or more, the number of those maximum depth is 5μm or more, as the surface defects before of the repeat,
A solution having a property of giving a result that the maximum length is not more than 1 piece / m ² than the number of pieces having a maximum length of 50 μm or more and a maximum depth of 5 μm or more. Support for film production method film production. 12. A metal support used in a method for producing a film, wherein a resin solution is cast on a metal support and formed into a film. 400-600 ppm dissolved by weight
A solution containing water is cast on the surface of the support, which is in contact with the film to be cast in production, to form a liquid film, the thickness of the liquid film is set to 500 to 600 μm, and the liquid film is set to 60 to 600 μm. After the film was dried at 65 ° C. for 30 minutes and the operation of peeling and removing the film was repeated 100 times, before and after that, as a surface defect of the support, the peripheral length L of the surface defect and the circle equivalent diameter D were determined. A support for producing a film by a solution casting method, wherein the support has a property of substantially giving the result that the number of those having a ratio L / D of 5.0 to 20 is 0/100 cm ² or less. 13. The evaluation method according to claim 1, wherein the resin is an aromatic polycarbonate. 14. The method according to claim 1, wherein the halogen-containing solvent is mainly composed of methylene chloride.
Or the evaluation method according to any one of 13. 15. The support according to claim 7, wherein the resin is an aromatic polycarbonate. 16. The method according to claim 7, wherein the halogen-containing solvent is mainly composed of methylene chloride.
16. The support according to any one of 2 or 15. 17. The support according to claim 7, wherein the halogen-containing solvent is mainly composed of a mixture of methylene chloride and 1,3-dioxolane. 18. A method for producing a film by an aromatic polycarbonate solution casting method, comprising using the support according to claim 7. Description: 19. A polycarbonate film produced by the film production method according to claim 18.