JPH08277360A - Aromatic polycarbonate solution composition and production of film - Google Patents

Abstract

PURPOSE: To obtain a composition useful for forming a film excellent in peelability, surface properties, transparency and optical homogeneity by using an aromatic polycarbonate solution containing a small amount of a lower aliphatic alcohol as a dope. CONSTITUTION: This composition is obtained by dissolving (B) 10 pts.wt. aromatic polycarbonate [preferably the one, comprising a recurring unit from 2,2-bis(4-hydroxyphenyl)propane and having 10,000-200,000 viscosity - average molecular weight] in (A) 15-90 pts.wt. solvent containing >=60wt.% preferably 90-99wt.% methylene chloride and 1-10wt.% 1-6C straight-chain or branched chainlike aliphatic alcohol (preferably methanol, ethanol, isopropanol or tert- butanol). The resultant solution composition is then cast onto a supporting substrate and the solvent is evaporated from the cast film containing the solvent to afford an aromatic polycarbonate film.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an aromatic polycarbonate.
The present invention relates to a solution composition used for producing a film.

The present invention also relates to a method for producing an aromatic polycarbonate film which is useful for optical applications such as display devices and electrical / electronic equipment applications. More specifically, when continuously casting an aromatic polycarbonate film by a solution casting method (casting method), it is excellent in releasability when peeling a casting film in a semi-dried state from a supporting substrate, Therefore, the present invention relates to a method for producing an aromatic polycarbonate film having good surface properties, transparency and optical homogeneity.

[0003]

2. Description of the Related Art In recent years, liquid crystal display devices have been attracting attention because of their low power consumption and excellent image quality, and are being put into practical use. In these liquid crystal display devices,
Polymer films are used for polarizing plates, protective layers, retardation plates, electrode substrates and the like. Among them, the polymer electrode substrate, that is, the plastic substrate is used instead of the conventional glass substrate for making the liquid crystal display lighter and thinner, and has extremely high optical isotropy in order to accurately transmit the transmitted polarized light to the liquid crystal layer. And homogeneity is required. Furthermore, heat resistance is required to withstand heat applied during processing such as film formation of the transparent electrode and formation of an alignment film. Therefore, unstretched polycarbonate film, polyarylate film, etc. are used, and from the viewpoint of heat resistance, a film made of aromatic polyethersulfone is also considered promising [Junji Takase, "Recent development of electrode substrate film. Development Trends ”, The Society of Polymer Science, Polymer Electronics Workshop, p20 (November 11, 1993)
Sun; at Sophia University)].

In particular, aromatic polycarbonate films are often used from the viewpoint of optical characteristics and economics. However, aromatic polycarbonate has a high polarizability because it contains an aromatic group in the molecule, and therefore has a drawback that even slight molecular orientation causes optical anisotropy in the aromatic polycarbonate film. ing. From this point of view, the development of a technique for forming an aromatic polycarbonate film excellent in optical isotropy by suppressing the molecular orientation as much as possible is an important issue.

On the other hand, the retardation film is used for improving image visibility in STN type liquid crystal display elements and TN type liquid crystal display elements, and converts elliptically polarized light transmitted through the liquid crystal layer into linearly polarized light. Play a role. These materials are mainly uniaxially stretched polycarbonate.
Films and polyvinyl alcohol films are used. As described above, the aromatic polycarbonate has a high polarizability because it contains an aromatic group in the molecule, and optical anisotropy is easily obtained by uniaxially stretching the film to orient the molecule. Therefore, it is advantageous that the retardation required for the retardation film can be obtained by a slight stretching, but on the other hand, it is difficult to obtain an optically homogeneous oriented film. In order to obtain such an oriented film, it is necessary to use a film which is optically highly isotropic at the stage of an unstretched film (raw film).

Generally, an aromatic polycarbonate film is formed by a melt extrusion method or a loose casting method by casting a solution, particularly a melt extrusion method (T die method) which is excellent in productivity.

The T-die method is widely used as a method for forming a plastic film. However, since a high-viscosity melt is extruded, polymer chains are likely to be oriented and stress strain tends to remain in the film. It is difficult to obtain optical isotropy and homogeneity. To lower the melt viscosity, lower the molecular weight of the plastic,
Alternatively, it is necessary to raise the film-forming temperature, but if the molecular weight is lowered, the mechanical properties of the film are deteriorated, and if the film-forming temperature is raised, thermal deterioration and coloring are easily induced. Also, T
Since the melt extruded from the die is directly cooled rapidly, streaks due to the T-die, so-called die lines, are likely to occur and it is difficult to obtain a film with high surface properties [Junji Takase, "Recent Development Trends of Electrode Substrate Films", Polymer Annual Meeting of Polymer Electronics Research Group p20 (November 1993)
May 11; at Sophia University)].

The surface properties and optical homogeneity required for films used in liquid crystal display devices are quite severe. For example, a plastic substrate is required to have a surface thickness variation of ± 5 μm or less, a retardation of 10 nm or less, and an optical axis orientation of ± 10 ° or less.
μm or less, phase difference 30 nm or less, and optical axis alignment ± 1 ° or less are required. Here, the optical axis orientation refers to the direction in which the refractive index is maximum in the film plane, that is, the direction of the slow axis. In reality, it is difficult to meet such strict requirements by the melt extrusion method.

Under these circumstances, the solution casting method (casting method) is considered to be a promising method for forming an aromatic polycarbonate film which has high surface properties, optical isotropy and homogeneity. The solution casting method is a solution composition (
Film is cast on a supporting substrate, then heated to remove most of the solvent to form a self-supporting film, then peeled from the supporting substrate and further dried by heating to remove the remaining solvent. Is the law. This solution casting method is currently used for forming a polycarbonate film used in a liquid crystal display device.

Usually, methylene chloride is often used as a solvent in the production of an aromatic polycarbonate film by a solution casting method. This is because the stability of the solution and the operability at the time of casting are excellent, but the aromatic polycarbonate has high adhesion to the metal plate which is usually used as a supporting substrate. That is, when the semi-dried film from which most of the solvent has been removed by heating after the dope casting is peeled from the supporting substrate, the adhesiveness is often high and the peelability is poor.
Due to the high peeling strength, the film has peeling streaks and peeling scratches, or the film is stretched and whitened at a part of the film, resulting in optical isotropy and homogeneity required for liquid crystal display applications. It is often difficult to obtain a film that is high and has good surface properties.

An easily conceivable means for solving such a problem is to add a release agent such as a fluorine-based, silicon-based or stearic acid-based release agent to the dope. For example, high-grade alcohol such as lauryl alcohol is used as a polycarbonate
A method of adding to a todope has been proposed (US Pat. No. 3,164,651). However, since these release agents remain in the film even after the film is formed, it is unavoidable that the glass transition point of the film is lowered. Further, the film may be whitened due to the deposition of the release agent. Furthermore, when a film containing a release agent is used for a liquid crystal display device or the like, it is not preferable because the adhesiveness to other members in the post-processing step may be deteriorated. From the above, aromatic polycarbonate
With respect to the solution casting method of a Bonnet film, there has been a demand for a method of improving the releasability of the cast film from the supporting substrate without impairing the physical properties of the film.

[0012]

DISCLOSURE OF THE INVENTION An object of the present invention is, in a solution casting method of an aromatic polycarbonate film, good peelability of the casting film from a supporting substrate, and thus surface property, transparency, It is an object of the present invention to provide a method for producing an aromatic polycarbonate film having excellent optical homogeneity and a solution composition used therefor.

[0013]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that lower aliphatic alcohols
When an aromatic polycarbonate solution composition containing a small amount of a polyester is used, the cast film has a good releasability from a supporting substrate, and therefore an aromatic polycarbonate having excellent surface properties, transparency and optical homogeneity. -The present invention was found by finding that a Bonnet film was obtained.

That is, the present invention is a solvent containing 15 to 90% by weight of methylene chloride and 1 to 10% by weight of a linear or branched aliphatic alcohol having 1 to 6 carbon atoms.
It is an aromatic polycarbonate solution composition in which 10 parts by weight of aromatic polycarbonate is dissolved in parts by weight.

Further, according to the present invention, the above solution composition is cast on a supporting substrate, and a cast film containing a solvent is heated to evaporate the solvent, thereby producing an aromatic polycarbonate film. Is the way.

There are no particular restrictions on the aromatic polycarbonate used in the present invention. There is no particular limitation as long as it is an aromatic polycarbonate that can obtain various desired film characteristics. In general, polymeric materials generally referred to as polycarbonates are those in which polycondensation reaction is used in the synthetic method and the main chains are bound by carbonic acid bonds. , Phenol derivative, and those obtained by polycondensation from phosgene, diphenyl carbonate and the like. Usually, an aromatic polycarbonate represented by a repeating unit containing 2,2-bis (4-hydroxyphenyl) propane, which is called bisphenol-A, as a bisphenol component is preferably selected. An aromatic polycarbonate copolymer can be formed by appropriately selecting various bisphenol derivatives.

As such a copolymerization component, this bisphenol
In addition to R-A, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 9,9-bis (4-hydroxyphenyl) fluorene, 1,1-bis (4-hydroxy) Phenyl)-
3,3,5-trimethylcyclohexane, 2,2-bis (4-hydroxy-3-methylphenyl) propane,
2,2-bis (4-hydroxyphenyl) -2-phenylethane, 2,2-bis (4-hydroxyphenyl)-
1,1,1,3,3,3-hexafluoropropane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) sulfide, bis (4-
Hydroxyphenyl) sulfone, 1,1-bis (4-
Examples thereof include hydroxyphenyl) -3,3,5-trimethylcyclohexane.

It is also possible to use an aromatic polyester carbonate which partially contains a terefultaric acid and / or isophthalic acid component. By using such a constitutional unit as a part of the constitutional component of the aromatic polycarbonate composed of bisphenol-A, an aromatic polycarbonate can be obtained.
The properties of the binder, such as heat resistance and solubility, can be improved, but the present invention is also effective for such a copolymer.

The viscosity average molecular weight of the aromatic polycarbonate used here is 10,000 or more and 200,000.
If it is 0 or less, it is preferably used. A viscosity average molecular weight of 20,000 to 120,000 is particularly preferable. Viscosity average molecular weight is 10,000
If a resin lower than 0 is used, the mechanical strength of the obtained film may be insufficient, and if the polymer has a high molecular weight of 400,000 or more, the viscosity of the dope becomes too large and a handling problem occurs, which is not preferable.

In the present invention, methylene chloride accounts for 60% by weight or more of the solvent used for the aromatic polycarbonate solution composition, and aliphatic alcohol having 1 to 6 carbon atoms accounts for 1 to 10% by weight. However, as the other remaining solvent, aromatic polycarbonate is dissolved in a high concentration and alcohol is used.
There is no particular limitation as long as it is compatible with the solvent and is a low boiling point solvent. However, there are surprisingly few such solvents. As a solvent having a dissolving power for aromatic polycarbonate, methylene chloride, chloroform, 1,2
-Dichloroethane, 1,1,2-trichloroethane, halogen-based solvents such as chlorobenzene, 1,3-dioxolane, 1,4-dioxane, cyclic ether-based solvents such as tetrahydrofuran, and ketone-based solvents such as cyclohexanone. To be

Water also exhibits the effect of improving the peelability, but in the case of methylene chloride, water is hardly mixed with methylene chloride, and when water is present, hydrogen chloride due to decomposition of methylene chloride is generated. The generation cannot be ignored, and there is a problem that rust or corrosion may occur in the metal part of the device used. For this reason, alcohol is preferably used. A solvent containing 60% by weight or more, preferably 70% by weight or more of methylene chloride, and more preferably methylene chloride except that it contains 1 to 10% by weight of aliphatic alcohol, but other solvents are used. be able to. That is, it is preferable that the solvent contains 90 to 99% by weight of methylene chloride and 1 to 10% by weight of a linear or branched aliphatic alcohol having 1 to 6 carbon atoms. When other solvent is used, it is not particularly limited and may be used in consideration of the effect. The effects here include mixing the solvent in a range that does not sacrifice solubility or stability, for example, improving the surface property of the film formed by the solution casting method (leveling effect), evaporation rate or system It has the effects of adjusting viscosity and suppressing crystallization. The kind and the addition amount of the solvent to be mixed may be determined depending on the degree of these effects, and one kind or two or more kinds may be used as the solvent to be mixed.

Other solvents which are preferably used include halogen solvents such as chloroform and 1,2-dichloroethane, hydrocarbon solvents such as toluene and xylene, ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone, ethyl acetate and acetic acid. Examples thereof include ester solvents such as butyl, and ether solvents such as ethylene glycol dimethyl ether and methoxyethyl acetate.

The type of alcohol added is limited by the solvent used. It is a necessary condition that the alcohol and the solvent are compatible with each other. These may be added alone,
There is no problem even if two or more kinds are combined. The alcohol in the present invention has 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms,
More preferably, 2 to 4 chain or branched aliphatic alcohols are preferable. Specific examples include methanol, ethanol, isopropanol, and tertiary butanol. Of these, ethanol, isopropanol and tertiary butanol have almost the same effects, but methanol is slightly less effective. Although the reason is not clear, it is presumed that it is related to the boiling point of the solvent, that is, the ease of flight during drying. Higher-grade alcohols having a higher boiling point are not preferable because they have a high boiling point and are likely to remain after the film formation.

The amount of alcohol added must be carefully selected. These are completely poor solvents for aromatic polycarbonate and are completely poor solvents. Therefore, too much cannot be added and should be the minimum amount that gives satisfactory strippability. Generally, it is 1 to 10% by weight, preferably 1 to 8% by weight, more preferably 1.5 to 5% by weight, based on the total amount of the solvent. 10% by weight
If the amount exceeds 1% by weight, the solubility of the solvent in the polymer and the dope stability are reduced, and if it is less than 1% by weight, the effect of improving the peelability becomes poor.

The solution composition of the present invention may be prepared by any method so long as a transparent solution having a low haze is obtained as a result. A predetermined amount of alcohol may be added to an aromatic polycarbonate solution previously dissolved in a solvent, or an aromatic polycarbonate may be added to a mixed solvent containing alcohol.
May be dissolved. Just as I said before,
Since the solvent is a poor solvent, the former method of adding it may cause clouding of the dope due to the precipitation of the polymer. Therefore, the latter method of dissolving it is preferable.

Although the solution concentration of the aromatic polycarbonate in the present invention depends on the cosolvent used and the molecular weight of the aromatic polycarbonate, it is based on 10 parts by weight of the aromatic polycarbonate. The amount of solvent is 15 to 90 parts by weight, preferably 2
It is 0 to 50 parts by weight. When the amount of the solvent exceeds this, the stability of the solution is not a problem, but it is not preferable because the effective concentration of the aromatic polycarbonate is low, and when a film is formed by the solution casting method using this solution composition. However, since the solution viscosity is low, external disturbance is likely to occur and the surface smoothness cannot be obtained, which is not preferable. Conversely, if the amount of solvent is less than this, it is difficult to obtain a stable dope. These concentrations are determined mainly in consideration of the stability of the dope and the solution viscosity.

In the present invention, aromatic polycarbonate
The solution composition (dope) is cast on a supporting substrate, and then the solvent is evaporated to obtain a film. The solvent can be evaporated by heating. The industrial continuous film forming step generally comprises three steps of a casting step, a pre-drying step and a post-drying step. The casting step is a step of smoothly casting the dope,
The pre-drying step is a step of evaporating and removing most of the solvent from the cast dope, and the post-drying step is a step of removing the remaining solvent.

In the casting process, a method of extruding from a die, a method of doctor blade, a method of reverse roll coater, etc. are used. Industrially, the most common method is to continuously extrude the dope from a die onto a belt-shaped or drum-shaped supporting substrate. Examples of the supporting substrate used include a glass substrate, a metal substrate such as stainless steel and a ferro type, and a plastic substrate such as polyethylene terephthalate. It goes without saying that the material and surface condition of the supporting substrate also have a great influence on the releasability of the cast film.
For example, a substrate coated with Teflon or the like having an extremely low surface tension has good peelability. However, in order to industrially continuously form a film having a highly surface property and excellent optical homogeneity, a metal substrate having a mirror-finished surface is most commonly used, and the present invention is such a metal substrate. The effect is recognized.

In general, the solution viscosity is an extremely important factor in forming a transparent and smooth film from a dope. Although the solution viscosity depends on the polymer concentration, molecular weight and solvent type, the solution composition of the present invention has a viscosity of 500
~ 50,000 cps, preferably 700 to 30,000
It is 0 cps. If it exceeds this range, the fluidity of the solution is lowered and a smooth film may not be obtained, which is not preferable. On the other hand, if it is less than that, the fluidity is too high, and it becomes difficult to uniformly discharge the dope from the T die used for normal casting, or the surface is disturbed due to external disturbance, and a uniform and smooth film cannot be obtained. The influence of the addition of alcohol on the solution viscosity is slight because the addition amount may be minute.

The temperature at the time of casting of the present invention depends on the solvent used, but the temperature is in the range of 10 to 40 ° C, preferably 15 to 35 ° C. In order to obtain a film having excellent smoothness, the solution extruded from the die needs to be cast and smoothed on the supporting substrate. At this time, if the casting temperature is too high, the surface is dried and solidified before it becomes smooth, which is not preferable. If the temperature is too low, the casting solution is cooled and the viscosity increases,
It is not preferable because it is difficult to obtain smoothness and dew condensation occurs.

Before transferring from the casting process to the drying process, the surface property of the film can be highly smoothed (leveling effect) by suppressing the drying for a certain period of time and ensuring the fluidity of the dope. Is.

In the pre-drying step, it is necessary to evaporate and remove most of the solvent from the dope cast on the supporting substrate in the shortest possible time. However, the drying conditions should be chosen carefully, as they undergo deformation due to foaming when rapid evaporation occurs. In the present invention, the drying should be started from the lowest boiling point of the solvents used, preferably from the range having the upper limit (boiling point −5 ° C.). After that, the temperature should be raised sequentially or continuously to improve the drying efficiency. The upper limit of the temperature at the final stage of this process is 1
20 ° C., preferably 100 ° C. is adopted. In this step, when the amount of residual solvent is large, 25% by weight is contained, and further higher temperature causes foaming, which is not preferable. Moreover, you may blow air as needed. In that case, the wind speed is generally 20 m / sec or less, preferably 15 m / sec.
A range of seconds or less is used. If it exceeds this, a smooth surface cannot be obtained due to wind disturbance, which is not preferable. The wind speed may be increased stepwise or continuously and is rather preferable. In the early stages, there may be no wind to avoid wind turbulence.

In this pre-drying step, the film is on the substrate and is peeled off from the substrate at the end of the step. At that time, deformation occurs because the film is soft when the amount of residual solvent is large, and when the residual solvent is small, even the cast film cast from the solution composition of the present invention has high adhesion to the supporting substrate and releasability. Deteriorates, resulting in stress strain, peeling streaks, and peeling scratches. Therefore, the residual solvent amount is an important factor, and the range of the residual solvent amount is preferably 5 to 25% by weight, and more preferably 7 to 20% by weight. In the solution casting method using a metal substrate, generally, the peelability is good at the beginning of film formation, but the peelability often decreases as the peeling is repeated. Although the cause of this is not clear, gradually many metal atoms with high surface tension are exposed on the surface of the substrate, or a very small amount of polymer adheres to the surface and it begins to work like an adhesive layer, so to speak. And so on. As a countermeasure for this, the peelability can be recovered by periodically cleaning the substrate surface, for example, by wiping the substrate surface with water.
In an industrial continuous film forming process, it is extremely troublesome work and is not efficient. According to the present invention, the releasability of the cast film from the supporting substrate can be favorably maintained without performing such an operation.

In the post-drying step, the film peeled from the substrate is further dried so that the residual solvent amount is 3% by weight or less,
It should be preferably 1% by weight or less, more preferably 0.5% by weight or less. This is because if there is a large amount of residual solvent, deformation occurs over time, or if heat is applied in the subsequent processing step of, for example, a liquid crystal display device, dimensional change, so-called heat shrinkage occurs. Generally, in the post-drying step, industrially, a method of drying while transporting the film by a pin tenter method, a roll suspension method, or the like is adopted, but in these methods, various forces are applied to the film during the drying. Therefore, in forming a film which is required to have a high degree of optical homogeneity such as for use in a liquid crystal display device, the drying temperature must be selected from the range in which the film does not deform. In general, the glass transition temperature of the aromatic polycarbonate used is Tg.
When (° C), a range of (Tg-120 ° C) to Tg,
A range of (Tg-100 ° C) to (Tg-10 ° C) is preferably selected. If it is more than that, thermal deformation of the film occurs, which is not preferable, and if it is less than that, the drying speed is remarkably slowed. Thermal deformation becomes less likely to occur as the residual solvent decreases. Therefore, it is preferable to adopt a method in which the temperature is initially low within the range, and then the temperature is raised stepwise or continuously. In this post-drying step, air may be blown as in the pre-drying step.

In the present invention, when the aromatic polycarbonate film is produced, the solvent gas concentration is high,
Drying may be carried out in an atmosphere of an inert gas such as nitrogen gas or carbon dioxide gas. When a flammable solvent is used, the drying method in the inert gas atmosphere is preferable from the viewpoint of safety considering the explosion limit of the solvent. In this case, the gas concentration of the solvent is 3 vo when considering the thermal energy of drying and the recovery efficiency.
1% or more is desirable. The oxygen concentration in the inert gas atmosphere is preferably 10 vol% or less.

The thickness of the film of the present invention is 10 to 300.
μm, preferably in the range of 50 to 200 μm. In particular, the thickness of 50 to 200 μm is preferably used for the plastic substrate and the original film for retardation film which constitute the liquid crystal display device. If it is thicker than this, it is difficult to remove the residual solvent, and if it is thinner than this, it is difficult to suppress thickness unevenness.

[0037]

According to the present invention, an aromatic polycarbonate solution containing a small amount of a lower aliphatic alcohol is used as a dope to form an aromatic polycarbonate which forms a film having good peelability. A bonnet composition is obtained. Further, according to the present invention, by using the solution as a dope,
In the solution casting method, it is possible to continuously obtain an aromatic polycarbonate film having a good releasability of the casting film from the supporting substrate, and thus having an excellent surface property, transparency and optical homogeneity.

[0038]

EXAMPLES The present invention will be described in detail below with reference to examples. However, the present invention is not limited to this. Each measurement performed in the examples was performed by the following method. Solution viscosity: Measured at 30 ° C. using a B type viscometer BH type manufactured by Tokyo Keiki Co., Ltd. Glass transition temperature: TA Instruments 2
The temperature rising rate was measured at 20 ° C./min using a 920 type DSC. Film thickness: A stylus type film thickness meter manufactured by Anritsu Corporation was used. Light transmittance: Shimadzu Corporation UV-visible spectroscope (UV
-240) is used. Haze value: An automatic digital haze meter-UDH-20D manufactured by Nippon Denshoku Industries Co., Ltd. was used. Phase difference and slow axis: Automatic birefringence meter KOBURA-21
ADH (made by KS Systems Co., Ltd.) was used. Quantification of residual solvent: The solvent was heated at 200 ° C. for 16 hours in a nitrogen atmosphere, and the weight was measured before and after the heating.

[Example 1] Polycarbonate containing bisphenol A as a constitutional unit to 40 parts by weight of a mixed solvent of methylene chloride and methanol containing 2% by weight of methanol.
Resin (Teijin Kasei Co., Ltd., Panlite C-1400,
Viscosity-converted molecular weight 37,000, glass transition point = 156
C.) 10 parts by weight was dissolved with stirring at 25.degree. C. to obtain a transparent and viscous dope. The solution viscosity of this dope at 15 ° C. was 7.5 × 10 ³ cps.

After the dope was filtered using a filter having a pore size of 5 μm, it was cast on a ferrotype substrate using a doctor blade. This substrate is a new ferrotype plate thoroughly washed and dried.

Then, 10 minutes at 40 ° C. and 10 minutes at 60 ° C.
The film was peeled off from the substrate after heating and drying for a minute. The peelability was extremely good. The amount of residual solvent in the film at the time of peeling was 15.9%, and the film thickness was 110 μm. This peeled film is heated at 100 ° C. for 10 minutes, 140
It was dried at ° C for 1 hour. No peeling scratches or peeling streaks were found on the film surface.

This operation is repeated using the same substrate, and the peelability is evaluated by examining the number of times peeling is possible without causing peel scratches or peel streaks on the film surface.
In this case, it was repeated 6 more times, but the peelability did not change, and all were good. These results are summarized in Table 1.

Example 2 Containing 3% by weight of ethanol,
10 parts by weight of the aromatic polycarbonate used in Example 1 was dissolved in 40 parts by weight of a mixed solvent of methylene chloride and ethanol with stirring at 25 ° C. to give a transparent and viscous dope. Got The solution viscosity of this dope at 15 ° C. was 7.1 × 10 ³ cps. The film was formed after filtration in the same manner as in Example 1, and the releasability was examined. Even after repeating 6 times, the releasability was good. These results are summarized in Table 1.

[Example 3] 3% by weight of isopropanol
A mixed solvent of methylene chloride and isopropanol 40 containing
The aromatic polycarbonate used in Example 1 based on parts by weight.
10 parts by weight of the solution were dissolved at 20 ° C. with stirring to obtain a transparent and viscous dope. The solution viscosity of this dope at 15 ° C. was 6.9 × 10 ³ cps. The film was formed after filtration in the same manner as in Example 1, and the releasability was examined. Even after repeating 6 times, the releasability was good. These results are summarized in Table 1.

[Example 4] 3 parts of tertiary butanol were used.
A mixed solvent of methylene chloride and butanol containing 40% by weight.
The aromatic polycarbonate used in Example 1 based on parts by weight.
10 parts by weight of the solution were dissolved at 20 ° C. with stirring to obtain a transparent and viscous dope. The solution viscosity of this dope at 15 ° C. was 7.6 × 10 ³ cps. The film was formed after filtration in the same manner as in Example 1, and the releasability was examined. Even after repeating 6 times, the releasability was good. These results are summarized in Table 1.

Comparative Example 1 10 parts by weight of the aromatic polycarbonate used in Example 1 was dissolved in 40 parts by weight of methylene chloride at 25 ° C. with stirring to give a transparent and viscous solution. I got a pu The solution viscosity of this dope at 15 ° C. was 6.8 × 10 ³ cps. When the film was formed after filtration in the same manner as in Example 1 and the peelability was examined, the peelability was good up to the second time, but the peel strength increased from the third time, and a large number of peeling lines were observed on the film surface. Was given. These results are summarized in Table 1.

Comparative Example 2 Example 1 was applied to 40 parts by weight of a mixed solvent of methylene chloride containing 0.5% by weight of methanol.
10 parts by weight of the aromatic polycarbonate used in Example 2 was dissolved at 25 ° C. with stirring to obtain a transparent and viscous dope. The solution viscosity of this dope at 15 ° C. is 6.8 × 1.
It was 0 ³ cps. When the film was formed after filtration in the same manner as in Example 1 and the peelability was examined, the peelability was good up to the second time, but the peel strength increased from the third time, and a large number of peeling lines were observed on the film surface. Was given. These results are summarized in Table 1.

[Comparative Example 3] 25 parts of 10 parts by weight of the aromatic polycarbonate used in Example 1 was added to 40 parts by weight of a mixed solvent of methylene chloride and ethanol containing 12% by weight of ethanol. It was dissolved with stirring at ℃, but the solubility was low and only a cloudy dope was obtained. These results are summarized in Table 1.

Example 5 10 mol% of 9,9-bis (4-hydroxyphenyl) fluorene unit and bisphenol A were added to 57 parts by weight of a mixed solvent of methylene chloride containing 3% by weight of ethanol. Aromatic polycarbonate having a unit of 90 mol% [viscosity average molecular weight 62,000, glass transition point = 173 ° C] 10 parts by weight was dissolved with stirring at 25 ° C to give a transparent and viscous dough. I got a pu

The solution viscosity of this dope at 30 ° C. is 1
It was 0.4 × 10 ³ cps. The diameter of this dope is 5μ
After filtering with a m-filter, it was cast on a ferrotype substrate with a doctor blade. This substrate is a new ferrotype plate thoroughly washed and dried. Subsequently, the film was peeled from the substrate by heating and drying at 40 ° C. for 10 minutes and 60 ° C. for 10 minutes. The peelability was extremely good, and peeling scratches and peeling streaks were not found on the film surface. The amount of residual solvent in the film at the time of peeling was 1
The film thickness was 5.5% and the film thickness was 108 μm. This operation was repeated 5 more times using the same substrate, but the peelability did not change and all were good. These results are summarized in Table 1.

Example 6 3% by weight of isopropanol
1,1-bis (4-hydroxyphenyl) based on 23 parts by weight of a mixed solvent of methylene chloride and isopropanol
Aromatic polycarbonate composed of 57 mol% of 3,3,5-trimethyltrimethylhexane and 43 mol% of bisphenol A unit [manufactured by BAYER, APEC-HT, viscosity average molecular weight = 22,000, glass transition Point = 207 ° C.] 10 parts by weight were dissolved at 25 ° C. with stirring to obtain a transparent and viscous dope. The solution viscosity of this dope at 15 ° C. was 8.8 × 10 ³ cps. The film was formed after filtration in the same manner as in Example 1, and the releasability was examined. The releasability was good even after repeating 6 times. These results are summarized in Table 1.

[Comparative Example 4] Copolymerized aromatic polycarbonate 1 used in Example 5 with respect to 57 parts by weight of methylene chloride.
0 part by weight was dissolved with stirring at 25 ° C. to obtain a transparent and viscous dope. The solution viscosity of this dope at 30 ° C. was 9.8 × 10 ³ cps. When the film was formed after filtration and the releasability was examined in the same manner as in Example 5, the releasability was good up to the second time, but the peel strength increased from the third time, and a large number of peeling lines were observed on the film surface. It was These results are summarized in Table 1.

Comparative Example 5 10 parts by weight of the copolymerized aromatic polycarbonate used in Example 6 was dissolved in 23 parts by weight of a mixed solvent of methylene chloride and ethanol at 25 ° C. with stirring. A transparent and viscous dope was obtained. This
Solution viscosity at 30 ° C. was 8.9 × 10 ³ cps. When the film was formed after filtration in the same manner as in Example 6 and the releasability was examined, the releasability was good up to the third time, but the peel strength increased from the fourth time, and many peeling lines were observed on the film surface. It was These results are summarized in Table 1.

[0054]

[Table 1]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kaoru Iwata 4-3-2 Asahigaoka, Hino City, Tokyo Teijin Limited Tokyo Research Center

Claims (11)

[Claims] 1. A straight-chain or branched-chain aliphatic alcohol having 1 to 6 carbon atoms in an amount of 60% by weight or more of methylene chloride.
Aromatic polycarbonate solution composition in which 10 parts by weight of aromatic polycarbonate is dissolved in 15 to 90 parts by weight of a solvent containing 10% by weight. 2. The solution composition according to claim 1, wherein the aromatic polycarbonate is an aromatic polycarbonate composed of repeating units from 2,2-bis (4-hydroxyphenyl) propane. Stuff. 3. An aromatic polycarbonate, wherein the aromatic polycarbonate is composed of repeating units from 2,2-bis (4-hydroxyphenyl) propane and other aromatic polycarbonates. The solution composition according to claim 1, which is a copolymer. 4. Another aromatic polycarbonate is bis (4-hydroxyphenyl) methane, 1,1-bis (4).
-Hydroxyphenyl) cyclohexane, 9,9-bis (4-hydroxyphenyl) fluorene, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 2,2-bis (4-hydroxy-) 3-
Methylphenyl) propane, 2,2-bis (4-hydroxyphenyl) -2-phenylethane, 2,2-bis (4-hydroxyphenyl) -1,1,1,3,3,3
-Hexafluoropropane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone and 1,1-bis (4-hydroxyphenyl) -3,3,5- The solution composition according to claim 3, which is at least one selected from the group consisting of trimethylcyclohexane. 5. The solution composition according to claim 1, wherein the aromatic polycarbonate has a viscosity average molecular weight of 10,000 or more and 200,000 or less. 6. The solution according to claim 1, wherein the solvent contains 90 to 99% by weight of methylene chloride and 1 to 10% by weight of a linear or branched aliphatic alcohol having 1 to 6 carbon atoms. Composition. 7. The remaining component of the solvent is chloroform,
The solution according to claim 1, which is at least one selected from the group consisting of 1,2-dichloroethane, toluene, xylene, acetone, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, ethylene glycol dimethyl ether, and methoxyethyl acetate. Composition. 8. The solution composition according to claim 1, wherein the aliphatic alcohol is at least one selected from the group consisting of methanol, ethanol, isopropanol, and tertiary butanol. 9. A method for producing an aromatic polycarbonate film, which comprises casting the solution composition according to claim 1 on a supporting substrate and evaporating the solvent from a casting film containing the solvent. Method. 10. The production method according to claim 9, wherein casting and solvent evaporation are continuously carried out. 11. The manufacturing method according to claim 9, comprising a casting step, a pre-drying step, and a post-drying step.