JPH10278056A - Cellulose ester film and its manufacture, solution composition for film making, and film base for photosensitive material using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent aldehyde from generating by a method wherein cellulose ester is dissolved with a solvent containing a cyclic dieter compound, and after the solution is made to flow to a supporting body, in a separation process, water of a specified wt.% range is contained in the solution. SOLUTION: Under a belt casting method, a solution 14 is made to cast to a supporting body 13 at a casting part 11, and then, is separated at a separating part 12. As a means to prevent acetal from generating, by adding water to a mixture liquid of dioxolane and alcohol, acetal which is a derivative of aldehyde is prevented from generating. When with a mixture liquid of the dioxolane solvent and water, the cellulose ester is dissolved in a range of water 2-15 wt.%, there is no generation of insoluble content such as a gel, and in addition, a cellulose ester film is manufactured using the solvent. By this method, the flatness is improved, and also, the photographing performance becomes favorable as well.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cellulose ester film, and more particularly, to a cellulose ester film which uses a solvent having a low environmental load and has excellent characteristics for use in photographs or liquid crystal display members.

[0002]

2. Description of the Related Art Conventionally, cellulose ester films have been widely used for various purposes such as photographic and optical applications.

In the production of these cellulose ester films, a method of casting a solution obtained by dissolving methylene chloride in a solvent is currently employed. However, in recent years, there has been a trend toward limiting the amount of methylene chloride used from the viewpoint of environmental load.

Therefore, as a solvent replacing methylene chloride, JP-A-7-278324 and 8-143708
No. 8-258065 proposes using dioxolane. Other techniques, such as those using a small amount of methylene chloride, are disclosed in
No. 5,792.

However, in the cellulose ester proposed above, for example, 1,3 dioxolane has a lower solubility of cellulose ester than methylene chloride, so that it is difficult to dissolve the cellulose ester at a high concentration. There is a disadvantage that the viscosity is increased.

Further, when the concentration of the cellulose ester is low due to the high boiling point of the solvent, it takes a long time to peel off from the support and a time for the peeling step.

For the improvement, a method of adding a poor solvent of alcohols to dioxolan containing moderate water to increase the viscosity of the dope, shorten the time required for peeling from the support, and improve the flatness after peeling (Japanese Patent Application Hei 9-67989).

However, a solvent containing a small amount of water is
When 1,3 dioxolane is recovered, distillation is difficult, and the distillation column has a large scale and requires a large amount of operating energy.

In the method for producing a cellulose ester film using dioxolane as a solvent, dioxolane is easily oxidized in a drying step, and aldehyde is produced. It is known in the art that this aldehyde has a significant adverse effect on photographic performance. For example, JP-A-8-43993 discloses a method for reducing its presence.
Nos. 8-57951 and 8-160567.

[0010]

The present inventors have now confirmed that when alcohols (methanol, ethanol, butanol, etc.) are used as a poor solvent in dioxolane, acetal, which is a derivative thereof in addition to aldehyde, is formed.

[0011] This is the aldehyde generated by handling dioxolane (eg, oxidation in a solvent storage tank, oxidation in a drying step, oxidation in a recovery step, etc.) and is formed by dehydration condensation with alcohols as poor solvents. is there. This compound has a boiling point much higher than aldehyde (about 100 ° C.)
Therefore, when a film is formed with a solvent containing the aldehyde, the amount remaining on the base is larger than that of the aldehyde. It was found that the remaining acetal was hydrolyzed by moisture in the film, returned to aldehyde and alcohol again, and adversely affected photographic performance.

As described above, in the production of a cellulose ester film using dioxolan as a solvent, it is very difficult to prevent the generation of aldehyde, and this is a problem that must be solved for practical use.

In recent years, the demand for cellulose ester films used not only for photography but also for optical applications has been increasing, and the influence on the global environment has been regarded as more important.

From the viewpoint of environmental load, the present inventor uses dioxolan, has sufficient workability as a photographic or liquid crystal display member, and has excellent dimensional stability and durability.
In particular, an object of the present invention is to provide a cellulose ester film having no adverse effect on photographic performance.

[0015]

Means for Solving the Problems The present inventors have made various efforts in the film forming process and the water contained in the solution or the film, and as a result, have found the present invention.

The object of the present invention is achieved by adopting one of the following constitutions.

(1) A method for producing a cellulose ester film, comprising casting a solution obtained by dissolving a cellulose ester in a solvent containing a cyclic diether compound onto a support and then peeling the solution. 2 in the lysate
A method for producing a cellulose ester film, characterized in that water is contained in an amount of more than 15% by weight and more than 15% by weight.

(2) The method for producing a cellulose ester film according to (1), wherein the residual amount of the solvent at the start of the peeling step is 50 to 450% by weight.

(3) The time from the start of casting the solution onto the support to the start of the step of peeling the cellulose ester film is from 3 seconds to 2 minutes, (1) or (2). 2) The method for producing a cellulose ester film according to the above.

(4) The surface temperature of the support at the start of the peeling step is -70 to 40 ° C. and the residual amount of the solvent is 100
(1), (2)
Or the method for producing a cellulose ester film according to (3).

(5) The cellulose ester film according to (4), wherein the support is a casting drum, and the time from the start of casting to the start of the step of peeling the cellulose ester film is 3 to 40 seconds. Manufacturing method.

(6) The surface temperature of the support during the peeling step is 0 to 75 ° C., and the residual amount of the solvent is 50 to 150% by weight, (1), (2) or (3). )).

(7) The support is a casting belt, and the time from the start of casting to the start of the peeling step is 2 hours.
The method for producing a cellulose ester film according to (4), wherein the time is 0 to 120 seconds.

(8) The solution according to any one of (1) to (7), wherein a solution in which the total of alcohol, diether cyclic compound and water contained in the solution is 30% or less is used. A method for producing the cellulose ester film according to the above.

(9) The method for producing a cellulose ester film according to any one of (1) to (8), wherein the casting of the dissolving solution is multilayer casting.

(10) After the solution is cast on a support, the solution is separated, and the residual solvent is reduced to 3.5% by weight or less through a step of holding and drying with a tenter. The method for producing a cellulose ester film according to any one of (1) to (9).

(11) In the step of holding and drying with a tenter, microwave heating is characterized.
0) The method for producing a cellulose ester film according to the above.

(12) A film base for a photographic light-sensitive material produced by the method for producing a cellulose ester film according to any one of (1) to (11).

(13) When a solution obtained by dissolving a cellulose ester in a solvent containing a cyclic diether compound is cast on a support, and then a film is formed through a step of peeling, the cellulose ester film is produced. A solution composition for film formation, wherein the solution contains more than 2% by weight and not more than 15% by weight of water.

(14) A cellulose ester film formed by casting a solution obtained by dissolving a cellulose ester in a solvent containing a cyclic diether compound on a support and then peeling the solution. But 2% by weight
A cellulose ester film containing more than 15% by weight of water.

(15) The film-forming film according to (13), wherein a plasticizer is added to the solution when the cellulose ester is dissolved using a solvent containing a cyclic diether compound to form a film. Lysate composition.

(16) The film base for a photographic material as described in (12), wherein the content of the total plasticizer is 8 to 16% by weight based on the cellulose ester.

In view of such circumstances, the present inventors have conducted intensive studies and found that, as a means for preventing the formation of acetal, the addition of water to a mixture of dioxolane and alcohol does not produce acetal. Was.
Even more surprisingly, when cellulose ester was dissolved in a mixture of dioxolane solvent and water, no insoluble matter such as gel was formed even when water was added up to 15% by weight. It turned out that there was no problem not only in the flatness but also in the photographic performance upon production.

This means that when using dioxolan described in JP-A-7-278324, a cellulose ester film can be produced by dehydration to substantially 0%, or the present inventors have previously made efforts to improve the quality of base flatness. From the point of view, it could not be imagined at all from the level of adding 2%.

That is, in the process of recovering and reusing the solvent, a distillation facility for removing contained water is not required,
In addition, the use of dioxolane significantly reduces the equipment cost in production and eliminates the energy required for distillation.

Further, by using a large amount of water, it is possible to avoid the generation of acetal which has been produced by conventional alcohols, so that there is no adverse effect on photographic performance, and a storage tank for alcohol is not required. In the present invention, water is
Normal industrial water may be used, but pure water is preferred.

Further, it is possible to provide a cellulose ester film having an improved film forming speed and excellent base flatness.

Here, the content of water in the cellulose ester film solution can be measured by either gas chromatography or Karl Fischer's method.

The percentage by weight of the solvent residual ratio in the solution after the casting and before the separation can be determined by a method of forcibly drying and removing the residual solvent described later or from a measured value of a transmission type radiation density. The percentage by weight of the solvent residual ratio is indicated by percentage by weight based on the cellulose ester.

The apparatus used for producing the cellulose ester film of the present invention may be the same as a conventionally used apparatus. It is not necessary to modify the manufacturing equipment using methylene chloride, such as the support for casting the solution and the peeling mechanism after removing the solvent.

Regarding the optical smoothness, a skilled person can observe the film surface with the naked eye while irradiating the film surface with light obliquely.

More strictly, however, as shown in FIG. 1, a parallel light 2 may be applied to the film 1 after the production, and a transmitted image thereof may be projected on a screen 3 and observed (in FIG. 1, reference numeral 4 denotes a halogen lamp). Alternatively, a light source light such as a mercury lamp and a device for making it parallel light, and 5 is a projected image on a screen).

By adopting such a method, if two kinds of bonded samples are prepared or a plurality of projection devices are prepared, a plurality of films can be viewed at the same time. Simultaneous observation is also possible, and the evaluation accuracy can be improved.

Next, the starting compounds, the production apparatus, the conditions and the like according to the present invention will be described.

The cellulose ester according to the present invention includes cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, cellulose acetate propionate and the like.
Cellulose triacetate having a bound acetic acid content of 54 to 62.5% is preferable, and a bound acetic acid content of 58 to 6
2.5% is preferable because the base strength is strong. As the cellulose triacetate, either cellulose triacetate synthesized from cotton linter or cellulose triacetate synthesized from wood pulp can be used alone or in combination.

If releasability from the belt or drum is a problem, it is preferable to use a large amount of cellulose triacetate synthesized from cotton linter having good releasability from the belt or drum because the productivity efficiency is high. The ratio of cellulose triacetate synthesized from cotton linter is 40
When the content is not less than 60% by weight, the effect of the releasability is remarkable.

The solvent used in the present invention is preferably a mixture of a good solvent and a poor solvent from the viewpoint of production efficiency.
The mixing ratio of the good solvent and the poor solvent is 70 to 95% by weight of the good solvent,
The content of the poor solvent is preferably 30 to 5% by weight. The concentration of the cellulose ester is preferably 10 to 50% by weight, and 18 to 20% by weight.
% Is more preferred.

In the present invention, a good solvent and a poor solvent are defined as those which dissolve the cellulose ester used alone as a good solvent, and those which swell or do not dissolve alone as a poor solvent. For this reason, a good solvent and a poor solvent change depending on the amount of bound acetic acid of the cellulose ester. For example, acetone is a good solvent when the amount of bound acetic acid is 55% and a poor solvent when the amount of bound acetic acid is 60%.

As a good solvent used in the present invention, a cyclic diether compound such as 1,3-dioxolane having a small environmental load is used. Examples of 1,3-dioxolanes include, for example,
1,3-dioxolan, 2-methyl-1,3-dioxolan, 4-methyl-1,3-dioxolan, 2-ethyl-1,3-dioxolan, 4-ethyl-1,3-dioxolan, 2,2- Dimethyl-1,3-dioxolan and the like. Among 1,3-dioxolanes, 1,
3-Dioxolane is particularly preferred.

The cyclic diether compounds may be used alone or in combination of two or more, or may be used by mixing with other good solvents. If necessary, it can be used by mixing with methylene chloride. In this case, the weight ratio of 1,3-dioxolane and the like to methylene chloride is 10:90 to 90:
10 is preferable, and 30:70 to 70:30 is more preferable.

The poor solvent used in the present invention includes, for example, alcohols having 1 to 8 carbon atoms such as methanol, ethanol and butanol, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, monochlorobenzene,
Benzene, cyclohexane, tetrahydrofuran, methyl cellosolve, ethylene glycol, monomethyl ether, acetone, toluene and the like can be mentioned. These poor solvents can be used alone or in an appropriate combination of two or more. However, since they can be peeled off with a large amount of residual solvent and have high production efficiency, methanol, ethanol, n
-Butanol and cyclohexane are preferred, and n-butanol and cyclohexane are particularly preferred.

In addition to the cellulose ester and the solvent, additives such as a plasticizer, an ultraviolet absorber, a matting agent, a dye, and an antioxidant can be added as necessary. May be added to the solvent before dissolving the cellulose ester or into the dope after dissolving the cellulose ester.

The type of the pressurized container is not particularly limited, and it is sufficient that the container can withstand a predetermined pressure and can be heated and stirred under pressure. For the pressurized container, other instruments such as a pressure gauge and a thermometer are appropriately arranged.

Pressurization may be carried out by pressurizing an inert gas such as nitrogen gas or by increasing the vapor pressure of the solvent by heating.

Heating is preferably performed from the outside. For example, a jacket type is preferable because temperature control is easy.

The heating temperature after the addition of the solvent is preferably not lower than the boiling point of the solvent used and not exceeding the boiling point of the solvent, and is preferably set in the range of not less than 60 ° C. and 80 to 110 ° C., for example. . The pressure is determined so that the solvent does not boil at the set temperature.

After the dissolution, the resin is taken out of the container while cooling, or is taken out of the container by a pump or the like, cooled with a heat exchanger or the like, and supplied for film formation. The cooling temperature at this time may be cooled to room temperature, but it is more preferable to cool to a temperature lower than the boiling point by 5 to 10 ° C. and perform casting at that temperature because the dope viscosity can be reduced.

In the present invention, a dope obtained by dissolving a cellulose ester in a solvent containing a cyclic diether compound is cast on a substrate (support) and then heated to remove a part of the solvent. After the (dope drying step), the film is peeled from the substrate, and the peeled film is dried (film drying step) to obtain a cellulose ester film.

In the production of a cellulose ester film according to the present invention, a method in which a solution of a cellulose ester is cast on a surface of a support at a relatively low temperature and the temperature of the solution (also referred to as a dope) is lowered to shape the film. It can also be preferably used in a method in which the solution is cast on a relatively hot support surface (usually, the surface temperature is lower than the boiling point of the solution) and the solvent is removed to shape the solution.

The former typical method includes a drum casting method in which the support is made into a drum shape and the manufacturing apparatus is made compact, and the latter representative method includes a belt casting method using a belt-like support.

As the support in the casting step, a belt-shaped or drum-shaped stainless steel mirror-finished is used. The temperature of the support in the casting step can be cast in a general temperature range of -70 ° C to a temperature lower than the boiling point of the solvent. In the drum casting method, it is preferable that the dope is cast on a support at 5 to 30 ° C., since the dope is gelled and the peeling limit time can be increased. preferable. The peeling limit time refers to the time during which the cast dope remains on the support at the limit of the casting speed at which a transparent film having good flatness can be continuously obtained. It is preferable that the peeling limit time is short because the productivity is excellent.

In the belt casting method, the temperature of the support depends on the boiling point of the solvent to be used, and is usually lower than the boiling point. Preferably, the surface of the support is maintained at a relatively high temperature of 40 to 75 ° C.

FIG. 2 is a schematic view of the drum casting method, in which the entire area of the casting section 11, particularly the area around the peeling section 12, is cooled. 13 is a support (in this case, a drum) and 14 is a solution (dope).

FIG. 3 is a schematic diagram of the belt casting method. In the casting section 11 and the peeling section 12, 13 is a support (in this case, a belt), and 14 is a solution (dope). FIG. 4 shows two dope tanks which can be cast in layers (solutions 14 and 14 '). In this case, the concentrations of the plurality of liquids to be cast may be the same or different.

Further, in either system, Japanese Patent Application Laid-Open
As described in JP-A-94725, a method of co-casting a solution of a cellulose ester having a lower concentration than the solution to be mainly cast on both sides of the solution to be mainly cast may be used.

The temperature of the dope at the time of peeling is 0 ° C. to 30 ° C.
° C is preferable because the base strength at the time of peeling can be increased and the base can be prevented from breaking at the time of peeling.
C. to 20 C. is more preferred.

After the film was peeled off, see JP-A-5-1854.
No. 45 and JP-A-6-278149, drying is performed while applying a constant tension with a tenter in the width direction of the film, and drying is performed until the residual solvent amount in the film becomes a predetermined amount. preferable.

The amount of residual solvent in the film is represented by the following equation.

Residual solvent amount = (weight of remaining volatile matter / weight of film after heat treatment) × 100% The weight of residual volatile matter is obtained by heating the film at 115 ° C. for 1 hour, calculating the weight of the film before the heat treatment, Is the value obtained by subtracting the weight of the film.

In the film drying step, the film peeled from the support is further dried so that the amount of the residual solvent is 3.5% by weight or less and 0.5% by weight or more. In the film drying step, a method of drying the film while transporting the film by a roll suspension method or a tenter method is generally employed. For photographic light-sensitive materials, drying while maintaining the width by a tenter method is preferable for improving dimensional stability. In particular, it is particularly preferable to maintain the width in a place where the amount of the residual solvent is large immediately after being peeled off from the support, since the effect of improving the dimensional stability is further exhibited. The means for drying the film is not particularly limited, and is generally performed using hot air, infrared rays, a heating roll, a microwave, or the like. In particular, it is preferable to use a microwave in terms of drying efficiency. The drying temperature is preferably divided into three to five stages in a temperature range of 40 ° C. to 150 ° C., and gradually increased, and more preferably performed in a temperature range of 80 ° C. to 140 ° C. in order to improve dimensional stability. .

The amount of the cyclic diether compound contained in the base is preferably from 0.020 mg / g to 4.000 mg / g. 0.020 mg / g to 1.000 mg / g is more preferable, and 0.030 mg / g to 0.070 mg / g.
Is even more preferred. The amount of the cyclic diether compound contained in the base was determined by head space type gas chromatography (equipment: HP5890 SERIESII / HP
5971A, HP9746 (manufactured by Hewlett-Packard), Column: DB-WAX (0.25 mmid × 60
m, 0.25 mm) (manufactured by J & W Scientific)) and a headspace sample heating temperature of 12
By heating at 0 ° C. for 30 minutes, the amount of the diether compound contained in 1 g of the base can be determined.

The thickness of the cellulose ester film according to the present invention is often 10 to 500 μm in dry film thickness,
It is preferably from 0 to 200 μm, particularly preferably from 100 to 130 μm.

The plasticizer that can be used in the present invention is not particularly limited, but in the case of a phosphate ester type, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl Phosphate, tributyl phosphate, etc., phthalic acid ester type, diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, etc., glycolic acid ester type, triacetin, tributyrin, butyl phthalyl butyl Glycolate, ethylphthalylethyl glycolate, methylphthalylethyl glycolate, butylphthalylbutyl glycolate, etc. Preferably used in combination is.

Preferred plasticizers include, for example, tricresyl phosphate, cresyl diphenyl phosphate, tributyl phosphate, diethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, triacetin, and ethyl phthalyl ethyl glycolate. Rate can be raised. It is preferable to use these plasticizers alone or in combination.

The use amount of these plasticizers is preferably 8 to 16% by weight based on the cellulose ester. Further, the photographic film is preferably used in an amount of 11 to 16% by weight, and this range is particularly favorable for the brittleness, workability, and bleed-out failure resistance.

[0076]

EXAMPLES The present invention will be described below in detail with reference to examples, but embodiments of the present invention are not limited thereto.

Example 1 1,3 dioxolane was recovered as an aqueous solution of 1,3 dioxolane by activated carbon adsorption. The liquid is dehydrated by simple distillation to a 1,3-dioxolane water azeotropic composition, and cyclohexane is added as an entrainer and simple distillation is performed to obtain 1,3 dioxolane containing 0.1% or less of water as a residue. Using 1,3 dioxolane, four kinds of dope preparation solvents were prepared.

(Dope Composition 1) 20 parts by weight of cellulose triacetate (61% acetylation degree synthesized from cotton) 1,3 dioxolane 95, 90, 85, 80 parts by weight Pure water 5,10,15, 20 parts by weight After the above three kinds of dope compositions were stagnated for another day,
After dissolving under pressure, the dry film thickness is set to 100 μm.
The film was uniformly cast on a stainless steel plate heated to 0 ° C using gisa, dried for 10 minutes, peeled off the film, and further fixed on a wooden frame and dried at 100 ° C for 20 minutes. Samples 1 to 3 and Comparative Sample 1 were used.

(Dope composition 2) Cellulose triacetate 20 parts by weight (Acetylation degree synthesized from cotton wool 61%) 1,3 dioxolane 85 parts by weight Pure water 5,7.5,10 parts by weight Ethanol 10,10 parts by weight 7.5, 5 parts by weight The above three dope compositions were prepared in the same manner as the above samples so that the dry film thickness became 100 μm, and these were designated as samples 4 to 6 of the present invention.

(Dope Composition 3: Comparative Example) Cellulose triacetate 20 parts by weight (degree of acetylation synthesized from cotton wool 61%) 1,3 dioxolane 85 parts by weight Ethanol 15 parts by weight A sample was prepared in the same manner as in the above samples 1 to 6 so as to have a thickness of 100 μm, and was set as a comparative sample 2.

Each of the bases (cut to a width of 35 mm and a length of 10 cm) and a Konica color film (Konica LV100) manufactured by Konica Co., Ltd. were tied together to give 60% RH, 40%.
Heat treatment was performed for 1 week in an environment of ° C., and the photographic performance after normal development processing (increase / decrease in fog density on the basis of unbound samples after heat treatment for 1 week) was examined. The base itself was analyzed by a solvent extraction method FID-gas chromatography to confirm the acetal content.

[0082]

[Table 1]

Samples 1 to 6 in the present invention had low fog and low acetal content, but Comparative Sample 2 outside the present invention was high, and Comparative Sample 1 was not practical because the finished film base was clouded. .

Example 2 (Sample 7 in the Present Invention) (Dope Composition A) 30 parts by weight of cellulose triacetate synthesized from cotton wool linter (61% acetylation degree) 70 parts by weight of cellulose triacetate synthesized from wood pulp Triphenyl phosphate 8 parts by weight Ethyl phthalylethyl glycolate 5 parts by weight 1,3 dioxolane 400 parts by weight Pure water 40 parts by weight The above is charged into a pressurized airtight container, and then under high pressure (internal pressure 7 kg / c)
m ² G), heated to 100 ° C., and a solution (dope) in which cellulose triacetate was completely dissolved with stirring.
I got

After cooling the dope to 70 ° C. and filtering the dope, the dry film thickness was adjusted to 60 μm + 60 μm on a stainless steel band (belt support) heated to 75 ° C. at a dope temperature of 75 ° C. using a belt casting device. So that the dope temperature is maintained at 75 ° C. on a stainless steel band,
After drying to a range where the peeling was possible, the dope was peeled off from the stainless band. At this time, the solvent residual ratio of the dope was 95% by weight. The time required from the casting of the dope to the peeling was 120 seconds.

After being peeled off from the stainless steel band, it was conveyed while keeping its width by a tenter, and then dried at 110 ° C. in a drying zone.
After drying for 5 minutes, Sample 7 in the present invention of a triacetate film was obtained.

Example 3 (Sample 8 in the Present Invention) (Dope Composition C) 30 parts by weight of cellulose triacetate synthesized from cotton linter (61% acetylation degree) 70 parts by weight of cellulose triacetate synthesized from wood pulp Triphenyl phosphate 12 parts by weight 1,3 dioxolane 200 parts by weight Pure water 15 parts by weight Ethanol 10 parts by weight The above is charged into a pressurized airtight container, and under high pressure (internal pressure 7 kg / c)
m ² G), heated to 100 ° C., and a solution (dope) in which cellulose triacetate was completely dissolved with stirring.
I got

After cooling the dope to 70 ° C. and filtering the dope, a dry film thickness of 120 μm was placed on a stainless steel drum (drum support) cooled to 5 ° C. using a drum casting apparatus.
m, the solution was uniformly cast by single casting (single-layer casting), held on a stainless steel drum for 10 seconds, and then the dope was peeled off.

At this time, the solvent residual ratio of the dope was 200% by weight.

After peeling off from the stainless steel drum, while holding and transporting by a tenter, 25
After drying for 5 minutes, Sample 8 of the present invention of a triacetate film was obtained.

Example 4 (Sample 9 in the Present Invention) A cellulose triacetate film was prepared by using a dope composition B and a dope composition C described below by a drum support casting method using a co-casting die.

(Dope Composition C) 30 parts by weight of cellulose triacetate synthesized from cotton fried linters (61% acetylation degree) 70 parts by weight of cellulose triacetate synthesized from wood pulp 500 parts by weight 1,3 dioxolane 50 parts by weight pure water Part The above is put into a pressurized airtight container, and under high pressure (internal pressure 7 kg / c
m ² G), heated to 110 ° C. and stirred, while stirring, a solution (dope) in which cellulose triacetate was completely dissolved.
I got

After cooling the dope to 70 ° C. and filtering the dope, a dry film thickness of 120 μm was formed on a stainless steel drum (drum support) cooled to 5 ° C. using a drum casting apparatus.
m was uniformly cast by co-casting (three-layer casting, coating film thickness: 50 μm + 110 μm + 50 μm), held on a stainless steel drum for 7 seconds, and then the dope was peeled off. At this time, the solvent residual ratio of the dope was 190% by weight.

After peeling off from the stainless steel drum, while holding and transporting by a tenter, 25
After drying for 9 minutes, Sample 9 of the present invention of a triacetate film was obtained.

Comparative Example 1 (Comparative Sample 3) (Comparative Dope Composition B) 30 parts by weight of cellulose triacetate synthesized from cotton wool linter (61% acetylation degree) 70 parts by weight of cellulose triacetate synthesized from wood pulp triphenyl Phosphate 8 parts by weight Ethylphthalylethyl glycolate 5 parts by weight 1,3 dioxolane 400 parts by weight Ethanol 60 parts by weight
m ² G), heated to 100 ° C., and a solution (dope) in which cellulose triacetate was completely dissolved with stirring.
I got

After cooling the dope to 70 ° C. and filtering the dope, the dry film thickness was adjusted to 60 μm + 60 μm on a stainless steel band (belt support) heated to 75 ° C. at a dope temperature of 75 ° C. using a belt casting device. So that the dope temperature is maintained at 75 ° C. on a stainless steel band,
After drying to a range where the peeling was possible, the dope was peeled off from the stainless band. At this time, the solvent residual ratio of the dope was 100% by weight. The time required from the casting of the dope to the peeling was 120 seconds.

After peeling from the stainless steel band, 110
It dried for 15 minutes in the drying zone of ° C, and obtained the comparative sample 3 of the triacetate film.

(Characteristic Evaluation) Film Smoothness Evaluation was performed by the method shown in FIG. 1 described above.

Evaluation criteria for film smoothness ：: No shading on the screen is observed. ：: A weak but wavy pattern is projected. Δ: A strong wavy pattern is projected. X: A clear vertical streak is projected. And △ is on the boundary of feasibility or impossibility, so that the problem remains at this level.

Tear Strength The tear strength was measured using a light load type tear strength tester (manufactured by Toyo Seiki Seisaku-sho, Ltd.), and expressed as a value converted to a film thickness of 120 μm.

Underwater curl degree A sample having a size of 10 cm × 10 cm was immersed in water at room temperature for 1 hour.
The measurement was performed according to method A.

In practice, it can be roughly evaluated as follows.

Less than 10 (1 / m): good Less than 10 to 20 (1 / m): somewhat good More than 20 (1 / m): bad photographic performance Example 1 The fog density was shown according to the same method as described above.

[0104]

[Table 2]

Samples 7 to 9 in the present invention have film flatness,
It can be seen that the underwater curl and the photographic performance are both at acceptable levels, while Comparative Sample 3 is significantly inferior.

[0106]

According to the present invention, the following effects can be obtained.

The use of a large amount of water makes it possible to avoid the generation of acetal which has been produced with conventional alcohols, so that there is no adverse effect on photographic performance and the need for an alcohol storage tank is eliminated.

In the process of recovering and reusing the solvent, a distillation facility for removing contained water is not required, and a large reduction in equipment cost in production by using dioxolane and energy required for distillation are not required. .

A cellulose ester film having an improved film-forming speed and excellent base flatness can be provided.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of an evaluation method of optical smoothness.

FIG. 2 is a schematic diagram of a drum casting method.

FIG. 3 is a schematic diagram of a belt casting method.

FIG. 4 is a schematic view showing an example of a co-casting method in a belt casting method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Film 3 Screen 4 Device which emits parallel light 11 Casting part 12 Peeling part 13 Support 14 Solution (dope)

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C08L 1/08 C08L 1/08 G03C 1/795 G03C 1/795 // B29K 1:00 B29L 7:00 (72) Inventor Yajima Takatoshi 1 Konica Stock Company, Sakura-cho, Hino-shi, Tokyo

Claims (16)

[Claims] 1. A method for producing a cellulose ester film, comprising: casting a solution obtained by dissolving a cellulose ester in a solvent containing a cyclic diether compound on a support, and peeling the solution; 2% by weight in the liquid
A water content of more than 15% by weight. 2. The method for producing a cellulose ester film according to claim 1, wherein the residual amount of the solvent at the start of the peeling step is 50 to 450% by weight. 3. The time from the start of casting the solution onto the support to the start of the step of peeling the cellulose ester film is 3 seconds to 2 minutes.
Or a method for producing a cellulose ester film according to item 2. 4. The support has a surface temperature of −70 to 40 ° C. at the start of the peeling step and a residual amount of solvent of 100 to 45 ° C.
4. The method for producing a cellulose ester film according to claim 1, wherein the amount is 0% by weight. 5. The cellulose ester film according to claim 4, wherein the support is a casting drum, and the time from the start of casting to the start of the peeling step of the cellulose ester film is 3 to 40 seconds. Production method. 6. The surface temperature of the support at the time of the peeling step is 0.
The method for producing a cellulose ester film according to any one of claims 1 to 3, wherein the temperature is from 75 to 75 ° C, and the residual amount of the solvent is from 50 to 150% by weight. 7. The method according to claim 1, wherein the support is a casting belt, and the time from the start of casting to the start of the peeling step is 20 to 1
The method for producing a cellulose ester film according to claim 4, wherein the time is 20 seconds. 8. The solution according to claim 1, wherein a total amount of the alcohol, diether cyclic compound and water contained in the solution is 30% or less.
The method for producing a cellulose ester film according to the above item. 9. The method for producing a cellulose ester film according to claim 1, wherein the solution is cast by multilayer casting. 10. The method according to claim 1, wherein after the solution is cast on a support, the solution is separated, held in a tenter and dried to reduce the amount of residual solvent to 3.5% by weight or less. Item 10. The method for producing a cellulose ester film according to any one of Items 1 to 9. 11. The method for producing a cellulose ester film according to claim 10, wherein microwave heating is performed in the step of holding and drying with a tenter. 12. A film base for a photographic light-sensitive material, produced by the method for producing a cellulose ester film according to claim 1. Description: 13. A method for producing a cellulose ester film by casting a solution obtained by dissolving a cellulose ester in a solvent containing a cyclic diether compound on a support and then peeling the solution to produce a cellulose ester film. A solution for film formation, wherein the liquid contains more than 2% by weight and not more than 15% by weight of water. 14. A cellulose ester film formed by casting a solution obtained by dissolving a cellulose ester in a solvent containing a cyclic diether compound onto a support and then peeling the solution, wherein the solution is 2. A cellulose ester film comprising more than 2% by weight and up to 15% by weight of water. 15. When dissolving a cellulose ester using a solvent containing a cyclic diether compound to form a film,
2. A plasticizer is contained in the solution.
4. The solution composition for film formation according to 3. 16. The film base for a photographic light-sensitive material according to claim 12, wherein the content of the total plasticizer is 8 to 16% by weight based on the cellulose ester.