JPH1171463A - Preparation of cellulose triacetate solution, preparation of cellulose triacetate film, and cellulose triacetate film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a solution wherein a cellulose triacetate is stably dissolved in an organic solvent other than chlorine-containing hydrocarbons, and a fine cellulose triacetate film using this. SOLUTION: In any of the steps in preparing a mixture of a cellulose triacetate having an average acetylation degree of 58.0% to 62.5% to and an organic solvent which is substantially free of chlorine-containing hydrocarbons and contains an acetone or the like as a main solvent, through a cold dissolving method or a pressure dissolving method, an ultrasonic wave is applied to obtain the cellulose triacetate solution having a high solubility and stability, The cellulose triacetate film having a high transparency is obtained by forming a film from this solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cellulose triacetate film useful for a silver halide photographic material or a liquid crystal image display, a method for producing a cellulose triacetate film, and a method for preparing a cellulose triacetate solution.

[0002]

2. Description of the Related Art Conventionally, chlorine-containing hydrocarbons such as methylene chloride have been used in the production of cellulose triacetate used for silver halide photographic materials and liquid crystal image display devices. Methylene chloride (boiling point 4
1 ° C.) has been conventionally used as a good solvent for cellulose triacetate, and is preferably used because it has a low boiling point in the film forming and drying steps of the production process and thus is easy to dry. Conversely, methylene chloride has a problem that it has a low boiling point and is easily volatilized, so that it is slightly leakable from the hermetic equipment, the recovery is limited, and it cannot be completely prevented from dissipating into the atmosphere. Recently, the use of chlorine-containing compounds such as perchrene and trichlene has been regulated due to suspicion of carcinogenicity.Methylene chloride does not have such a problem, but the chlorine-containing compound, methylene chloride, will be subject to some restrictions in the future. It is becoming a target. Therefore, it has become urgent for those skilled in the art to search or study a solvent for cellulose triacetate other than methylene chloride. Acetone (boiling point: 56) is known as an organic solvent having solubility in cellulose triacetate.
° C), methyl acetate (boiling point 56.3 ° C), tetrahydrofuran (boiling point 65.4 ° C), 1,3-dioxolane (boiling point 75 ° C), nitromethane (boiling point 101 ° C), 1,4-dioxane (boiling point 101 ° C) , Epichlorohydrin (boiling point: 116 ° C), N-methylpyrrolidone (boiling point: 202 ° C) and the like. When these organic solvents were actually subjected to a dissolution test, some of them were not necessarily good solvents, and few of them could be put to practical use, such as those having a risk of explosion and those having a high boiling point.

[0003] Among the above organic solvents, acetone having a low boiling point only swells cellulose triacetate by a usual method but does not dissolve it. In recent years, attempts have been made to dissolve cellulose triacetate in acetone to produce fibers and films.

[0004] M. G. FIG. Cowie and others are Makrom
ol. chem. 143, p. 105 (1971), cellulose triacetate (acetylation degree: 60.1% to 61.3%) was cooled from -80 ° C to -70 ° C in acetone, and then heated to 0.5 to 5% by heating. It is reported that a weight percent dilute solution was obtained. Such a method of melting at a low temperature is called a cooling melting method. In addition, Kenji Ude et al. Described spinning technology using a cooling dissolution method in "Dry spinning of cellulose triacetate from acetone solution" in Textile Machinery Society, Vol. 34, pp. 57-61 (1981). I have.

Further, Japanese Patent Application Laid-Open Nos. 9-95544 and 9-95544
Japanese Patent Application Laid-Open No. 95557 discloses that cellulose triacetate is dissolved by a cooling dissolution method using an organic solvent substantially consisting of acetone, or using acetone and another organic solvent in common, and applied to the production of a film. Has been proposed. According to the above-mentioned study, it is necessary to lower the temperature to -30 ° C. despite using acetone, which is a good solvent for cellulose triacetate.

JP-A-9-95538 discloses that cellulose triacetate is dissolved by a cooling dissolution method using an organic solvent selected from ethers, ketones or esters other than acetone to form a film. It is stated that 2-methoxyethyl acetate, cyclohexanone, ethyl formate, methyl acetate and the like are preferable as the solvent. In the above method, the transparency and stability reproducibility of the prepared cellulose triacetate solution are poor unless the low polymerization degree portion of the cellulose triacetate is removed in advance, and conventionally commercially available photographic grade cellulose triacetate cannot be used as it is. There was a complication.

[0007]

When a solution of cellulose triacetate is prepared in a mixed solvent system of acetone and another solvent using the above-described cooling dissolution method, the above-mentioned commercially available cellulose triacetate is used as it is. If the low polymerization degree components contained in these are not removed beforehand, there is a problem in transparency and stability of the cellulose triacetate solution. Such properties are serious drawbacks when using, for example, a silver halide photographic light-sensitive material or a cellulose triacetate film produced in a liquid crystal image display device, and must be eliminated during the production process.

An object of the present invention is to provide a method for preparing an excellent cellulose triacetate solution without using a chlorinated hydrocarbon such as methylene chloride, a method for producing a cellulose triacetate film, and a cellulose triacetate film produced by those methods. Is to provide.

Another object of the present invention is to provide an excellent cellulose triacetate film by using a commercially available photographic grade cellulose triacetate as it is.

[0010]

The above object has been attained by the following (1) or (2).

(1) The average degree of acetylation is 58.0% or more.
A mixture of 5% or less of cellulose triacetate and an organic solvent substantially free of chlorine-containing hydrocarbon
Cellulose triacetate through a step of cooling to a temperature of 0 to -50 ° C., a step of heating the cooled mixture to 0 to 50 ° C. to dissolve the cellulose triacetate, and a step of adding an additive to the solution and mixing if necessary. A method for preparing a cellulose triacetate solution, which comprises sonicating in any one of the preparation steps in preparing the cellulose triacetate.

(2) The average degree of acetylation is 58.0% or more.
10 kg of a mixture of 5% or less of cellulose triacetate and an organic solvent substantially free of chlorinated hydrocarbons
A method for preparing a cellulose triacetate solution, which comprises irradiating ultrasonic waves during any of the steps of preparing a solution by applying a pressure of not less than / kg / cm ^{2 and not} more than 5000 kg / cm ² .

The present invention can be carried out in the following modes (3) to (8).

(3) The ultrasonic irradiation is one in which two kinds of oscillation frequencies different from each other are resonated. (1)
Or the method for preparing a cellulose triacetate solution according to (2).

(4) The cellulose triacetate solution contains a main solvent selected from acetone, 1,3-dioxolan, 1,4-dioxane, methyl acetate, methyl acetoacetate, 2-methoxyethyl acetate, fluoroalcohol and ethyl formate. Characterized by containing (1)
The method for preparing a cellulose triacetate solution according to any one of (1) to (3).

(5) The cellulose triacetate is 2
The method for preparing a cellulose triacetate solution according to any one of (1) to (4), having a viscosity average degree of polymerization of 20 or more and 500 or less.

(6) The concentration of cellulose triacetate in the cellulose triacetate solution is 10% by weight to 50% by weight.
The method for preparing a cellulose triacetate solution according to any one of the above.

(7) The method according to any one of (1) to (6), wherein the cellulose triacetate solution contains a plasticizer in an amount of 5% by weight or more and 30% by weight or less based on cellulose triacetate. A method for preparing a cellulose triacetate solution.

(8) The method for preparing a cellulose triacetate solution according to (2), wherein the pressure is increased by a hydrostatic pressure method.

The object of the present invention is to provide the following (9) or (1)
0).

(9) The average degree of acetylation is 58.0% or more.
A mixture of 5% or less of cellulose triacetate and an organic solvent substantially free of chlorine-containing hydrocarbon
To -10 ° C., dissolving the cellulose triacetate by heating the cooled mixture to 0 to 50 ° C., and, if necessary, adding an additive to the solution and mixing. In forming a cellulose triacetate film through a step of casting the cellulose triacetate solution on a support and a step of evaporating the solvent and drying the film, ultrasonic irradiation is performed in any of the steps of preparing the cellulose triacetate solution. A method for producing a cellulose triacetate film, comprising:

(10) The average degree of acetylation is 58.0% or more and 6
A mixture of 2.5% or less of cellulose triacetate and an organic solvent substantially free of chlorinated hydrocarbons was added to 10%
In forming a cellulose triacetate film through kg / cm ² or more 5000 kg / cm ² or less applying pressure of a cellulose triacetate solution prepared by evaporating process and a solvent is cast on a support and drying the film, A method for producing a cellulose triacetate film, comprising irradiating ultrasonic waves in any of the processes for preparing the cellulose triacetate solution.

The present invention can be carried out in the following modes (11) to (16).

(11) The method for producing a cellulose triacetate film according to (9) or (10), wherein the ultrasonic irradiation is a resonance of two types having different oscillation frequencies.

(12) The cellulose triacetate solution contains a main solvent selected from acetone, 1,3-dioxolan, 1,4-dioxane, methyl acetate, methyl acetoacetate, 2-methoxyethyl acetate, fluoroalcohol and ethyl formate. The method for producing a cellulose triacetate film according to any one of (9) to (11), wherein the cellulose triacetate film is contained.

(13) The method for producing a cellulose triacetate film according to any one of (9) to (12), wherein the cellulose triacetate has a viscosity average polymerization degree of 220 or more and 500 or less.

(14) The concentration of cellulose triacetate in the cellulose triacetate solution is 10% by weight.
(9) to (1)
The method for producing a cellulose triacetate film according to any one of 3).

(15) The method according to any one of (9) to (14), wherein the cellulose triacetate solution contains a plasticizer in an amount of 5% by weight or more and 30% by weight or less based on cellulose triacetate. A method for producing a cellulose triacetate film.

(16) The method for producing a cellulose triacetate film according to (10), wherein the pressure is increased by a hydrostatic pressure method.

Further, the object of the present invention can be implemented by the following (17) or (18).

(17) The average acetylation degree is 58.0% or more and 6
A mixture of 2.5% or less of cellulose triacetate and an organic solvent substantially free of chlorinated hydrocarbons was added to -1
Prepared through cooling to 00 to -10 ° C, heating the cooled mixture to 0 to 50 ° C to dissolve cellulose triacetate, and adding and mixing additives as needed. In forming a cellulose triacetate film through a step of casting the cellulose triacetate solution on a support and a step of evaporating the solvent and drying the film, the cellulose triacetate solution is subjected to sonication in any of the preparing processes. A cellulose triacetate film characterized by being formed using the above.

(18) The average degree of acetylation is 58.0% or more and 6
A mixture of 2.5% or less of cellulose triacetate and an organic solvent substantially free of chlorinated hydrocarbons was added to 10%
In forming a cellulose triacetate film through kg / cm ² or more 5000 kg / cm ² or less applying pressure of a cellulose triacetate solution prepared by evaporating process and a solvent is cast on a support and drying the film, A cellulose triacetate film formed by using a cellulose triacetate solution that has been subjected to ultrasonic irradiation in any of the preparation processes.

The present invention can be carried out in the following modes (19) to (24).

(19) The ultrasonic irradiation is characterized by resonating two types having different oscillation frequencies.
7) or the cellulose triacetate film according to (18).

(20) The cellulose triacetate solution contains a main solvent selected from acetone, 1,3-dioxolan, 1,4-dioxane, methyl acetate, methyl acetoacetate, 2-methoxyethyl acetate, fluoroalcohol and ethyl formate. (1)
(7) The cellulose triacetate film according to any one of (19) to (19).

(21) The cellulose triacetate film according to any one of (17) to (20), wherein the cellulose triacetate has a viscosity average degree of polymerization of 220 or more and 500 or less.

(22) The concentration of cellulose triacetate in the cellulose triacetate solution is 10% by weight.
The cellulose triacetate film according to any one of (17) to (21), wherein the content is from 10 to 50% by weight.

(23) The cellulose triacetate film according to any one of (17) to (22), wherein the cellulose triacetate solution contains a plasticizer in an amount of 5% by weight or more and 30% by weight or less based on the cellulose triacetate. .

(24) The cellulose triacetate film according to (18), which is pressurized by a hydrostatic pressure method.

Hereinafter, the present invention will be described in detail.

The average acetylation degree of the cellulose triacetate used in the present invention is 58.0% or more and 62.5% or less, and in the present invention, this range is referred to as cellulose triacetate. Generally, cellulose triacetate having a degree of acetylation of 53% or more and 56% or less is referred to as cellulose diacetate, and has a degree of acetylation of 58% or more and 62% or less.
Those with 5% or less are called cellulose triacetate. In addition to the degree of acetylation, the indication of the degree of reactivity includes the degree of substitution or the degree of acetylation. The acetylation degree is expressed in terms of acetic acid (CH ₃ COOH)% by weight when acetic acid reacts with the hydroxyl group of cellulose, and is 62.5% when the acetic acid is reacted at the maximum. The degree of acetylation is determined by the acetyl group (C
(H ₃ CO) wt%, 44.8% when reacted at maximum. The degree of substitution represents the degree to which the acetyl group has reacted with the OH group of the cellulose molecule, and the case where all the OH groups have reacted is represented as 3.00. This means that three acetyl groups were substituted for three OH groups in the glucose unit, the minimum unit of the cellulose molecule. The degree of acetylation can be measured by a method described in ASTM D-817-97, such as a test method for cellulose acetate.

The polymerization degree (viscosity average) of the cellulose triacetate used in the present invention is preferably from 220 to 500. In general, a cellulose triacetate film containing cellulose triacetate, the degree of polymerization is required to be 200 or more in order for the mechanical strength of the fiber or molded article to be tough, and the so-called "Cellulose Handbook" edited by Hiroshi Sobue and Nobuhiko Migita. Asakura Shobo (1985), edited by Hiroshi Marusawa and Kazuo Uda, "Plastic Materials Course 17", Nikkan Kogyo Shimbun (1970). The polymerization degree of the cellulose triacetate film of the present invention is more preferably from 250 to 350. The viscosity average polymerization degree can be measured by an Ostwald viscometer, and is determined from the measured intrinsic viscosity [η] of the cellulose triacetate film by the following equation.

DP = [η] / Km In the formula, DP is a viscosity average degree of polymerization, and Km is a constant of 6 × 10 ^-4. Examples of cellulose as a raw material of cellulose triacetate used in the present invention include cotton linter and wood pulp. And cellulose triacetate from either of them can be used, or may be used as a mixture. Some raw materials have many low molecular weight components. JP-A-9-9
Nos. 5538, 9-95544 and 9-5557 disclose that cellulose triacetate having a low molecular weight easily undergoes crystallization in a cooling dissolution method, and the presence of fine crystals reduces the dissolution in acetone. Cellulose triacetate solution (hereinafter sometimes referred to as dope) has low stability, and microcrystals are easily generated again. It is further stated that the optical properties of the resulting film are also reduced.

The cellulose triacetate used in the present invention is preferably of a photographic grade, and commercially available photographic grades should be obtained with satisfactory qualities such as viscosity average polymerization degree, acetylation degree and low molecular weight component. Can be done. Manufacturers of photographic grade cellulose triacetate include Daicel Corporation, Coatles, Hoechst and Eastman Kodak, and any photographic grade cellulose triacetate can be used.

The main solvent contained in the cellulose triacetate solution (hereinafter also referred to as dope) of the present invention is at least one selected from acetone, 1,3-dioxolan, 1,4-dioxane, methyl acetate, methyl acetoacetate, and fluoroalcohol. One solvent may be contained, two or more of the above solvents may be contained, or a poor solvent for cellulose triacetate described below or a solvent that cannot sufficiently dissolve cellulose triacetate may be contained. The content of the main solvent was 4% in the total solvent of the cellulose triacetate solution.
0 to 99% by weight, preferably 55 to 90% by weight, more preferably 50 to 85% by weight.

The fluoroalcohol useful in the present invention may be any one which can be easily evaporated and dried in the film drying step. Such a fluoroalcohol preferably has a boiling point of 165 ° C or lower, preferably 111 ° C or lower, and more preferably 80 ° C or lower.
The following is preferred. Fluoro alcohols have 2 carbon atoms
To about 10, preferably about 2 to 8.
Further, the fluoroalcohol is a fluorine atom-containing aliphatic alcohol and may or may not have a substituent. As the substituent, an aliphatic substituent with or without a fluorine atom, an aromatic substituent and the like are preferable. Such fluoroalcohols are, for example, (the boiling point in the following parentheses) 2-fluoroethanol (103 ° C.) 2,2,2-trifluoroethanol (80 ° C.), 2,
2,3,3-tetrafluoro-1-propanol (10
9 ° C.), 1,3-difluoro-2-propanol (55
° C), 1,1,1,3,3,3-hex-2-methyl-
2-propanol (62 ° C), 1,1,1.3,3,3
-Hexafluoro-2-propanol (59 ° C), 2,
2,3,3,3-pentafluoro-1-propanol (80 ° C), 2,2,3,4,4,4-hexafluoro-1-butanol (114 ° C), 2,2,3,3 4,
4,4-heptafluoro-1-butanol (97 ° C.),
Perfluoro-t-butanol (45 ° C) 2,2,3,3,4,4,5,5-octafluoro-1
-Pentanol (142 ° C) 2,2,3,3,4,4-hexafluoro-1,5-pentanediol (111.5 ° C) 3,3,4,4,5,5,6,6 7,7,8,8,8
-Tridecafluoro-1-octanol (95 ° C) 2,2,3,3,4,4,5,5,6,6,7,7,7,
8,8,8-Pentadecafluoro-1-octanol (165 ° C) 1- (pentafluorophenyl) ethanol (82 ° C) 2,3,4,5,6-pentafluorobenzyl alcohol (115 ° C) It is. One or more of these fluoroalcohols can be used.

Examples of the poor solvent for cellulose triacetate or a solvent similar thereto include ethers having 3 to 12 carbon atoms, ketones having 4 to 12 carbon atoms, esters having 3 to 12 carbon atoms, and carbon atoms, excluding the above-mentioned solvents. 1 to 8
Alcohols, nitrohydrocarbons having 1 to 12 carbon atoms, or hydrocarbons having 5 to 8 carbon atoms can be used. For example, ethers such as tetrahydrofuran, diisopropyl ether, ethylene glycol monomethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol dimethyl ether, ethylene glycol monobutanolanisole, and phenetole; ketones such as methyl ethyl ketone;
Examples of esters such as methyl isobutyl ketone or cyclohexanone include alcohols such as methyl formate, ethyl formate, propyl formate, butyl formate, ethyl acetate, propyl acetate, butyl acetate, and ethylene glycol diacetate. As nitro hydrocarbons such as methanol, ethanol, propanol, isopropanol, n-butanol, s-butanol, t-butanol, 2-methyl-2-butanol or cyclohexanol,
Examples of hydrocarbons such as nitromethane and nitroethane include cyclohexane, cyclopentane, cycloheptane and the like. 1 to 6 of these poor solvent or a similar solvent in a cellulose triacetate solution solvent.
0% by weight can be contained. When these solvents are used together with the main solvent, when the cellulose triacetate solution is cast on the support, gelation occurs by evaporating the solvent and by lowering the temperature of the support during casting, thereby increasing the film forming speed. In addition to this, the resulting cellulose triacetate film also has the effect of improving the planarity of the finished cellulose triacetate film, and it is preferable to use a mixture of a main solvent and a poor solvent or a similar solvent as much as possible. The amount is preferably from 10 to 45% by weight based on the total amount of the solvent. More preferably, it is 15 to 50% by weight. Preferred examples of the poor solvent for increasing the film formation rate include methanol, ethanol, n-butanol, cyclohexane and the like.

Here, "substantially does not include"
It means that the proportion of the chlorinated hydrocarbon in the organic solvent is less than 5% by weight, preferably less than 2% by weight.

Although the above-mentioned cooling dissolution method of a mixed solvent using acetone as a main solvent is not so excellent in solubility, the ultrasonic dissolution method of the present invention is carried out in any of the preparation steps to obtain a cooling dissolution method. Alternatively, the solubility of cellulose triacetate is also very good even by the pressure dissolution method, such as the above-mentioned microcrystals are unlikely to occur, and the transparency of the dope is good,
Moreover, it was found that the stability of the dope with time was good, and the optical characteristics of the film were also very good. When acetone is used in the cooling dissolution method, a low-molecular-weight substance can be removed with a solvent such as acetone by appropriately mixing a main solvent or a poor solvent that promotes solubility or a solvent similar thereto. Not necessarily. However, there is no problem if such a low molecular weight material is removed before use.

The amount of cellulose triacetate in the cellulose triacetate solution was 10
Although it is prepared so as to contain 50 to 50% by weight, in the organic solvent composition of the present invention, a high-concentration cellulose triacetate solution can be prepared. If the concentration is too high, the viscosity of the solution is too large, and it may be difficult to form a film,
The preferred cellulose triacetate solution has a cellulose triacetate concentration in the range of 10% to 50% by weight. Further, the range is preferably from 15% by weight to 45% by weight.

The cooling dissolution method is described in JP-A-9-5538.
Nos. 9-5544 and 9-95557, the outline of which is described. First, the mixture-
100 to -10 ° C (preferably -80 to -10
° C, more preferably -50 to -20 ° C, most preferably -50 to -30 ° C). Cooling, for example,
It can be carried out in a dry ice / methanol bath (−75 ° C.) or a cooled ethylene glycol solution (−30 to −20 ° C.). When cooled in this way, the mixture of cellulose triacetate and the mixed solvent may solidify in some cases.

Next, when the cooled product is heated to 0 to 50 ° C., the cellulose triacetate dissolves in the mixed solvent. The temperature may be raised only at room temperature or may be heated in a warm bath. In this way, a homogeneous solution is obtained.
The operation of cooling and heating may be repeated in order to accelerate the dissolution. Whether or not the dissolution is sufficient can be determined only by visually observing the appearance of the solution. In the cooling dissolution method, it is preferable to use a closed container in order to avoid water contamination due to condensation during cooling. In the cooling and heating operation, if the pressure is increased during cooling and the pressure is decreased during heating, the dissolution time can be further reduced. In order to perform pressurization and decompression, it is desirable to use a pressure-resistant container.

In the present invention, it has been found that the solubility can be reduced in a short time by performing the ultrasonic treatment in any of these dissolving processes. In particular, it is a preferable embodiment to perform ultrasonic treatment in the swelling process. We believe that by inserting the ultrasonic element into the liquid during the swelling process and irradiating it, cellulose triacetate is easily loosened, and the solvent is solvated to the cellulose triacetate molecule to a considerable extent, so that the solubility is increased. .

As described above, the concentration of the cellulose triacetate of the dope of the present invention is characterized in that a high concentration of the dope can be obtained, and a cellulose triacetate solution having a high concentration and excellent stability can be obtained without relying on the means of concentration. What is obtained is also a feature of the present invention. After further dissolving at a low concentration to facilitate dissolution, the solution may be concentrated using a concentration means. The method of concentration is not particularly limited, but, for example, a low-concentration solution is guided between the cylindrical body and the rotation locus of the outer periphery of the rotating blade rotating in the circumferential direction inside the cylindrical body, and between the solution. A method of obtaining a high concentration solution while evaporating the solvent by giving a temperature difference (for example, Japanese Patent Application Laid-Open No. Hei 4-25951)
No. 1), a heated low-concentration solution is blown into a container from a nozzle, and the solvent is flash-evaporated until the solution hits the inner wall of the container from the nozzle. (For example, USP 2,541,012, US Pat. No. 2,541,012)
858,229, 4,414,341, and 4,504,355).

Another embodiment of the present invention is a pressure dissolving method for cellulose triacetate. Unlike the above-mentioned cooling dissolution method, in general, the dissolution phenomenon of a polymer compound is that a good solvent is solvated closely to a polymer and is not thread-shaped, but many solvents are solvated around the molecule and relatively elongated. It has a random or rod-like shape and is said to exist relatively independently. It is considered that the pressure dissolution method of the present invention facilitates the penetration of the organic solvent into the solid or swollen state of cellulose triacetate under the pressurized state, and the cellulose triacetate molecules are easily loosened and solvated. In this sense, the present invention by pressurization is a novel dissolution method.

The method of dissolving the cellulose triacetate under pressure when using acetone of the present invention will be described.
First, cellulose triacetate is added to an organic solvent containing acetone as a main component in a pressurized container, and a pressure of 10 kg / cm ² or more and 5000 kg / cm ² or less is applied, and a cellulose triacetate solution is prepared simply by returning to normal pressure. I can do it. It is easy to take out the cellulose triacetate solution, and 10 kg / cm ² or more and 5000 kg / cm ²
Any device that can apply the following pressure may be used. The pressure applied in the present invention is in the range of 10 kg / cm ^{2 to} 5000 kg / cm ² , preferably 50 kg / cm ^{2 to} 30 kg / cm ^2.
00 kg / cm ² or less, more preferably 100 kg / cm ²
cm ² or more and 2000 kg / cm ² or less.

The pressurizing method and pressurizing device of the present invention are not particularly limited as long as they are performed by a device capable of pressurizing. The pressurizing method and pressurizing device suitable for the present invention are used in other industries. Method and apparatus can be used, for example, a hydrostatic pressure method (Cold Isos
Atomic Press (abbreviated to CIP or rubber press method) is preferable as a method and equipment capable of safely applying a high pressure. This hydrostatic pressure method and apparatus are preferable because a hydrostatic pressure can be uniformly applied to the mixture of cellulose triacetate and the organic solvent from all directions, and a cellulose triacetate solution having an excellent dissolved state can be obtained. Rubber or a metal which can be easily deformed by pressure, for example, an aluminum container may be used as the material of the container for enclosing the mixture in the hydrostatic pressure method. Alternatively, a method in which the mixture is sealed in an easily deformable closed container such as rubber, and the mixture is transferred and moved in the closed container while applying hydrostatic pressure, may be intermittently prepared. Alternatively, a means for compressing the mixture by placing the mixture in a container having a lid that can be slid up and down and pushing the lid in can be used. The mixture may be kneaded and extruded using a pressurized extruder. During the preparation of the cellulose triacetate solution of the present invention, pressurization may be performed intermittently, and the dissolution rate can be increased by repeating pressurization and normal pressure. The pressurizing device may or may not be equipped with a stirrer.

In the pressure dissolution method of the present invention, ultrasonic irradiation can be performed in any step of the pressure dissolution process. Among them, irradiation is preferably performed in a swelling step or a pressure dissolution step before dissolution. Also in the pressure dissolution method, it was recognized that the solubility was increased by performing the ultrasonic treatment, and that the quality of the dissolved cellulose triacetate solution was further improved.

The ultrasonic irradiation device used in the present invention may be one used for a general ultrasonic disperser, an ultrasonic cleaner or the like. The ultrasonic irradiator is composed of an ultrasonic generating oscillator and an oscillator driven high frequency oscillator, and the oscillation frequency is 10k.
Hz to 10 MHz, preferably 20 to 500 kHz
It is. The output of the ultrasonic wave is preferably about 0.1 to 500 W / cm ² , and more preferably 5 to 100 W / cm ² .
A thyristor oscillator is also used, in which case a series inverter is used, and the frequency may be several tens of kHz. In particular, in a preferred embodiment of the present invention, ultrasonic irradiation at two different frequencies is performed, and the inventor has found that the resonance effect of the two frequencies further enhances the dissolving effect.
Since the two types have different frequencies, the same type of oscillator may be used or different types of oscillators may be used. The ultrasonic irradiation time differs depending on the vibration frequency and the output, and it is difficult to display the time. However, from the viewpoint of shortening the dissolution time, it is preferably about 5 minutes to 5 hours, and more preferably 1 hour or less.

In preparing the cellulose triacetate solution of the present invention, the container may be filled with an inert gas such as nitrogen gas. The viscosity of the cellulose triacetate solution immediately before film formation may be in a range that can be cast at the time of film formation, and it is usually preferably adjusted in the range of 150 ps to 2000 ps.

In the cellulose triacetate solution of the present invention, various additives depending on the use can be added in each preparation step.

For a silver halide photographic light-sensitive material, a plasticizer or a colorant for preventing light piping or an ultraviolet light inhibitor for improving mechanical properties or imparting water resistance, and for a liquid crystal image display device, a heat-resistant material. It is desirable to add an antioxidant or the like that imparts moisture resistance.

As the plasticizer, phosphoric acid esters, carboxylic acid esters, glycolic acid esters and the like are preferably used. Examples of phosphate esters include triphenyl phosphate (TPP), tricresyl phosphate (TCP), cresyl diphenyl phosphate (CDP).
P), octyl diphenyl phosphate (ODPP),
Examples include diphenylbiphenyl phosphate (BDP), trioctyl phosphate (TOP), and tributyl phosphate (TBP). Examples of the carboxylic acid ester include dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), and dioctyl. Phthalate (DOP), diethylhexyl phthalate (DEHP), acetyltriethyl citrate (TE
AC), acetyl tributyl citrate (TBAC), butyl oleate (BO), methylacetyl ricinoleate (AML), dibutyl sebacate (DBS), and the like. Examples of glycolic acid esters include triacetin (TA), tributyrin (TB), butyl phthalyl butyl glycolate (BPBG), ethyl phthalyl ethyl glycolate (EPEG), methyl phthalyl ethyl glycolate (MPEG), and the like. Above all, TPP, TC
P, CDPP, TBP, DMP, DEP, DBP, DO
P, DEHP, TA, EPEG and BDP are preferred. Particularly, TPP, DEP, EPEG, and BDP are preferable. These plasticizers may be used alone or in combination of two or more.
The amount of the plasticizer added is 5 to cellulose triacetate.
It is preferable that the content be in the range of 8% by weight to 16% by weight. These compounds may be added together with the cellulose triacetate and the solvent during the preparation of the cellulose triacetate solution, or may be added during or after the solution preparation.

Further, the following general formulas (I), (II) and (III)
May be added.

[0065]

Embedded image

In the formula, R is an alkyl group having 1 to 4 carbon atoms. Examples of the compound represented by the above (I), (II) or (III) include sodium 2,2'-methylenebis (4,6-di-t-butylphenyl) phosphate (ADK STAB NA-10, Asahi Denka Kabushiki Kaisha) Co., Ltd.) and screws (p
-Methylbenzylidene) sorbitol (Gerol M
D, manufactured by Shin Nippon Rika Co., Ltd.) and bis (p-ethylbenzylidene) sorbitol (NC-4, Mitsui Toatsu Chemicals, Inc.)
Manufactured).

As the antioxidant, those represented by the following general formula (IV) are used.

[0068]

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R ₁ represents an alkyl group, and R ₂ , R ₃ and X
Is a hydrogen atom, alkyl group, alkenyl group, aryl group, heterocyclic group, alkoxy group, alkenoxy group, aryloxy group, alkylthio group, alkenylthio group, arylthio group, heterocyclic oxy group, hydroxy group, amino group, carbamoyl Group, sulfamoyl group, alkoxycarbonyl group, aryloxycarbonyl group, halogen atom, nitro group, cyano group, acyl group, and acyloxy group. m represents an integer of 0 to 2. R ₂ , R ₃ and X may be the same or different. The alkyl group is, for example, methyl, ethyl, propyl, i-propyl, t-butyl, cyclohexyl, t-hexyl, t-
Represents a linear, branched, or cyclic alkyl group such as octyl, dodecyl, hexadecyl, octadecyl, and benzyl, and the alkenyl group is, for example, vinyl, allyl,
-Represents a linear, branched, or cyclic alkenyl group such as pentenyl, cyclohexenyl, hexenyl, dodecenyl, and octadecenyl, and the aryl group is, for example, a benzene monocyclic or fused polycyclic aryl group such as phenyl, naphthyl, and anthranyl. Wherein the heterocyclic group is, for example,
Containing at least one of a nitrogen atom, a sulfur atom, and an oxygen atom such as furyl, pyrrolyl, imidazolyl, pyridyl, purinyl, chromanyl, pyrrolidyl, and morpholinyl;
Represents a group consisting of a 7-membered ring. Among them, hindered phenol compounds are preferred, and 2,6-di-t-butyl-p-
Cresol, pentaerythrityl-tetrakis [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionate], triethylene glycol-bis [3
-(3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-
Bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t
-Butylanilino) -1,3,5-triazine, 2,2
-Thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N , N'-Hexamethylenebis (3,5-di-t-butyl-4-hydroxy-
Hydrocinnamamide), 1,3,5-trimethyl-2,
4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-t-
Butyl-4-hydroxybenzyl) -isocyanurate. In particular, 2,6-di-t-butyl-p-
Cresol, pentaerythrityl-tetrakis [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionate], triethylene glycol-bis [3
-(3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] is most preferred. Also, for example,
N, N'-bis [3- (3,5-di-t-butyl-4-
Hydrazine-based metal deactivators such as hydroxyphenyl) propionyl] hydrazine and tris (2,4-di-t
A phosphorus-based processing stabilizer such as (-butylphenyl) phosphite may be used in combination. The amount of these compounds to be added is 1 ppm by weight based on cellulose triacetate.
1.0% is preferable, and 10 ppm to 1000 ppm is more preferable.

As the coloring agent for preventing light piping, compounds represented by the following formulas (V) and (VI) can be added.

[0071]

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[0072] wherein, X represents an oxygen atom or an NR _23. R _{1 to} R ₈ and R _{12 to} R ₂₃ each represent a hydrogen atom, a hydroxyl group, an aliphatic group, an aromatic group, a heterocyclic group, a halogen atom, a cyano group, a nitro group, COR ₉ , COOR ₉ , NR ₉ R ₁₀ ,
NR ₁₀ COR ₁₁ , NR ₁₀ SO ₂ R ₁₁ , CONR ₉ R ₁₀ , S
O ₂ NR ₉ R ₁₀ , COR ₁₁ , SO ₂ R ₁₁ , OCOR ₁₁ , N
R ₉ CONR ₁₀ R ₁₁ , CONHSO ₂ R ₁₁ , or SO ₂ N
Represents HCOR ₁₁ , wherein R ₉ and R ₁₀ each represent a hydrogen atom, an aliphatic group, an aromatic group, or a heterocyclic group; R ₁₁ represents an aliphatic group;
Represents an aromatic group or a heterocyclic group. The aliphatic group represented by R _{1 to} R ₂₃ is an alkyl group having 1 to 20 carbon atoms (for example, methyl, ethyl, n-butyl, isopropyl, 2-ethylhexyl, n-decyl, n-octadecyl), 1
~ 20 cycloalkyl groups (e.g., cyclobenzyl,
A cyclohexyl) or allyl group, which further has a substituent (for example, a halogen atom, a hydroxyl group, a cyano group, a nitro group, a carboxylic acid group, an aryl group having 6 to 10 carbon atoms, an amino group having 0 to 20 carbon atoms, An amide group of numbers 1 to 20,
A carbamoyl group having 1 to 20 carbon atoms, an ester group having 2 to 20 carbon atoms, an alkoxy group or an aryloxy group having 1 to 20 carbon atoms, a sulfonamide group having 1 to 20 carbon atoms, and 0 carbon atoms
It may have up to 20 sulfamoyl groups, a 5- or 6-membered heterocyclic ring. The aromatic group represented by R _{1 to} R ₂₃ represents an aryl group having 6 to 10 carbon atoms such as phenyl and naphthyl, and the above-mentioned substituents and methyl having 1 to 20 carbon atoms;
It may have a substituent consisting of an alkyl group such as ethyl, n-butyl, t-butyl and octyl. R _{1 to} R ₁₁
The heterocyclic group represented by represents a 5- or 6-membered heterocyclic ring and may have the substituent described above. The general formula (V) below
Preferred examples of the compound represented by (VI) are shown below.

[0073]

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[0074]

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[0075]

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[0076]

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[0077]

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[0078]

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The content of the coloring agent is 10 ppm or more and 1000 ppm by weight based on cellulose triacetate.
Or less, more preferably 50 ppm or more and 500 ppm or less. By including a coloring agent in this way,
The light piping of the cellulose triacetate film can be reduced, and the yellow tint can be improved.

Further, various additives as described below may be added to the cellulose triacetate solution of the present invention as needed at the stage of preparation according to the use. As additives, ultraviolet absorbers, as stabilizers kaolin, talc,
There are inorganic fine particles such as diatomaceous earth, quartz, calcium carbonate, barium sulfate, titanium oxide, and alumina; salts of alkaline earth metals such as calcium and magnesium; and antistatic agents, flame retardants, lubricants, oils, and the like.

Prior to casting, the cellulose triacetate solution was filtered using a suitable filter medium such as a wire mesh or flannel,
It is necessary to remove foreign substances such as undissolved substances, dust and impurities by filtration.

A method for producing a cellulose triacetate film by a solution casting method using the cellulose triacetate solution of the present invention will be described. As the equipment for producing the cellulose triacetate film of the present invention, those conventionally used for producing cellulose triacetate films can be used. The dope prepared by the above-described preparation apparatus is sent to a pressurized die through a pressurized fixed-quantity gear pump that can perform a high-precision fixed-quantity liquid supply by, for example, the number of rotations. The dope sent from the precision gear pump to the pressing die is uniformly cast on the support running endlessly from the die (slit) of the pressing die.
The film is peeled off from the support as a freshly dried dope film (web), dried while being passed through a rotating roll group, and the dried film is transported and wound up to a predetermined length by a winder.

As a casting method useful in the present invention, a method in which the prepared dope is uniformly extruded from a pressure die onto a support, and a film thickness of the dope once cast on the support is adjusted by a blade. There are a method using a doctor blade, a method using a reverse roll coater that adjusts with a roll that rotates in the reverse direction, and the like, but a pressing die is preferable. The pressure die includes a coat hanger type and a T-die type, and any of them is useful in the present invention. In addition to the methods mentioned here, various methods for casting a cellulose triacetate film from a conventionally known cellulose triacetate solution (for example, JP-A Nos. 61-94724 and 61-947).
No. 148013, JP-A-4-85011, 4-28
Nos. 6611, 5-185443, 5-18544
Nos. 5, 6-278149, 8-207210, etc.) can be preferably used, and by setting each condition in consideration of the difference in the boiling point of the solvent to be used, etc., the respective publications can be used. The same effects as described can be obtained.

The endless support used for producing the cellulose triacetate film of the present invention may be a drum whose surface is mirror-finished by chrome plating,
A stainless belt (also referred to as a band), which is mirror-finished by surface polishing, is used.

The pressure die used for the production of the cellulose triacetate film of the present invention may be disposed on the support at one or more pressure dies. Preferably it is one or two. When two or more dope units are installed, the amount of the dope to be cast may be divided into various ratios for each die, and the dope is sent to the dice at a respective ratio from a plurality of precision metering gear pumps.

The drying of the dope on the support in the production of the cellulose triacetate film of the present invention is generally carried out by heating the dope from the surface of the drum or belt, that is, from the surface of the web on the support. There is a method of applying wind from the back side, a liquid heat transfer method of transferring the temperature to the surface of the drum or belt by contacting the liquid from the back side opposite to the dope side of the belt or drum,
A backside liquid heat transfer system is preferred. The surface temperature of the support before casting may be any number of times as long as it is lower than the boiling point of the solvent used for the dope. However, in order to promote drying and to lose fluidity on the support, it is preferable to set the temperature slightly lower than that of acetone. The speed at which the cellulose triacetate film is produced depends on factors such as the length of the belt, the drying method, and the composition of the dope solvent, but it can be said that it almost depends on the amount of the residual solvent at the time when the web is separated from the belt. If the solvent concentration in the vicinity of the belt surface in the dope film thickness direction is too high depending on the heating method, the dope will remain on the belt when peeled off and hinder the next casting, so the peeling residue is Absolutely not. Therefore, the entire thickness of the web at the time of peeling must be strong enough to withstand peeling. The residual solvent at the time of peeling differs depending on the method of drying on the belt, and a method of transferring heat from the belt or the back of the drum is better than a method of drying by blowing air from the surface of the dope.

The amount of residual solvent in the film according to the present invention is measured as follows, and is expressed for a dry film.

The test film or web (A) is placed in a weighing bin and precisely weighed.
After heating at 0 ° C. for 3 hours, the mixture was cooled to room temperature so as not to absorb moisture, weighed to obtain a completely dry film weight (B), and a residual solvent ratio (%) = {(AB) / B} × 100. expressed.

The film drying method for producing the cellulose triacetate film of the present invention will be described. The web peeled at the peeling position immediately before the support makes one round is alternately transported through rolls arranged in a staggered manner, or
The peeled web may be transported in a non-contact manner by holding both ends of the web with a clip-shaped material, and applying a wind of a predetermined temperature to both sides of the web (which is becoming a film) during transport. In the case of rapid drying, first drying is performed at a temperature that does not cause foaming, followed by high-temperature drying.

In the drying step after peeling from the support, the web shrinks in the width direction due to evaporation of the solvent, but in order to improve the flatness of the finished film, it is necessary to dry the film while suppressing shrinkage as much as possible. is there. Further, in order to manufacture at a high speed, it is necessary to apply a high temperature. In such a case, for example, the entire drying process or a part of the process as disclosed in JP-A-62-46625 is required. It is preferable to use a method (tenter method) in which the web is dried while holding both ends of the web width with a clip in the direction.

Further, there is also a method of positively stretching in the width direction. In the present invention, for example, JP-A-62-115035
And JP-A-4-152125 and JP-A-4-284221.
And the stretching methods described in JP-A Nos. 4-298310 and 4-298310 can also be used.

The drying temperature in the drying step of the cellulose triacetate film of the present invention is preferably from 80 to 250 ° C., particularly preferably from 100 to 180 ° C. The drying temperature, the amount of drying air, and the drying time vary depending on the solvent used, and may be appropriately selected according to the type and combination of the solvents used. The amount of the residual solvent in the final film is preferably 2% by weight or less, more preferably 0.4% by weight or less, and particularly preferably 0.1% by weight or less. By setting the amount of the residual solvent in the film in this range, a film having good dimensional stability can be obtained. The steps from casting to post-drying may be performed under an air atmosphere or under an inert gas atmosphere such as nitrogen gas.

The winding machine for producing the cellulose triacetate film of the present invention may be of a generally used constant tension type.

The film thickness of the finished film of the present invention varies depending on the purpose of use, but the concentration of the solids contained in the dope, the slit width of the die, the slit width of the die, and the thickness are 5 to 500 μm. The die pressure, the casting speed and the like may be adjusted. Preferably, the thickness after drying is 20 to 200 μm, and more preferably, the thickness after drying is 6 μm.
It is 0 to 125 μm.

A method for measuring the acetylation degree and the viscosity average polymerization degree of the cellulose triacetate used in the present invention will be described.

1) Degree of acetylation (%) of cellulose triacetate Degree of acetylation shall be measured by a saponification method. The dried cellulose triacetate is precisely weighed and dissolved in a mixed solvent of acetone and dimethyl sulfoxide (volume ratio of 4: 1), and a predetermined 1N aqueous sodium hydroxide solution is added thereto.
Saponify at 25 ° C. for 2 hours. Phenolphthalein is added as an indicator and excess sodium hydroxide is titrated with 1 N sulfuric acid (concentration factor; F). A blank test is performed in the same manner as described above. Then, the degree of acetylation (%) is calculated as follows.

Degree of acetylation (%) = (6.05 × (B−A) × F) / W In the formula, A is the amount of 1N sulfuric acid (ml) required for titration of the sample, and B is the amount of 1N sulfuric acid required for the blank test. (Ml), F is 1N
The sulfuric acid factor, W, indicates the sample weight.

2) Viscosity-average degree of polymerization (DP) of cellulose triacetate About 0.2 g of absolutely dried cellulose triacetate is precisely weighed and dissolved in 100 ml of a mixed solvent of methylene chloride: ethanol = 9: 1 (weight ratio). This is measured for drop seconds at 25 ° C. using an Ostwald viscometer, and the degree of polymerization is determined by the following equation.

Η _rel = T / Ts [η] = (lnη _rel ) / CDP = [η] / Km where, T: the number of seconds of falling of the measurement sample Ts: the number of seconds of falling of the solvent alone C: concentration (g) / L) Km: 6 × 10 ^-4

[0100]

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

The transparency of the solution in the examples, the stability with time of the solution, the amount of residual solvent in the film, the flatness of the film, the tear strength of the film, the tensile strength of the film, the elastic modulus of the film, and the folding resistance of the film The following methods were used to measure and evaluate the properties of the film and the haze of the film. Here, the dry film refers to a film cut out after winding in a winding step in a final stage of a cellulose triacetate film manufacturing step. Hereinafter, a dry film may be simply abbreviated as a film.

(Filterability of dope) Circular area 100 cm
⁽² ) A container having a fixing shelf for fixing a filter cloth in the middle stage in a brass pressurized airtight container having a height of 25 cm was facilitated. Azumi Filter Paper Co., Ltd.'s “Azumi Filter Paper No. 244” was used as the filter cloth, cut into round pieces of 100 cm ² and set on a shelf. The cellulose triacetate film solution was placed in this container, and the pressure was increased to 2 atm. went. The filterability was evaluated based on the time required for filtration. Filterability was defined as the ratio of the filtration time of the test cellulose triacetate solution to the filtration time of the cellulose triacetate solution dissolved in ordinary methylene chloride at normal temperature and pressure.

(Transparency of Solution) The cellulose triacetate solution was put in a transparent container, and the transparency was visually observed and evaluated as follows.

A: Transparent and uniform dope B: Slight turbidity C: Turbidity, insoluble matter visible D: Extremely turbid, many insoluble matter seen

(Stability of Solution over Time) The cellulose triacetate solution was placed in a transparent container,
The transparency was observed after 48 hours and 48 hours, and at the same time, the container was inverted to observe the change in the fluidity of the solution.

A: A transparent and uniform dope, and the dope moved smoothly even when the container was inverted. B: There was slight turbidity but transparency, and when the container was inverted, the moving interface was slightly crushed. C: There is turbidity, insolubles are seen, and when the container is turned upside down, the dope moves unevenly. D: Remarkably turbid, there are many insolubles, and the phases are separated.

(Film flatness) A black paper was stuck on a flat desk, a sample film having a size of 100 cm × 40 cm was placed thereon, and three fluorescent lamps arranged diagonally upward were projected on the film to obtain a fluorescent lamp. The flatness was evaluated as follows according to the degree of bending.

A: All three fluorescent lamps look straight B: Fluorescent lamp looks slightly bent C: Fluorescent lamp looks bent D: Fluorescent lamp looks large ridge

(Tear strength of film)
After humidifying for 4 hours in a room conditioned at 3 ° C. and a relative humidity of 55% RH, the sample was cut out to a sample size of 50 mm × 64 mm.
It was determined by measuring according to SO 6383 / 2-1983.

(Film Tensile Strength and Elastic Modulus) A film was conditioned at a temperature of 23 ° C. and a relative humidity of 55% RH.
After humidity control for 4 hours, the sample was cut into a width of 10 mm and a length of 200 mm.
A tensile test was performed at 0 mm / min.

(Folding resistance of film)
4 hours in a room conditioned at 55 ° C. and a relative humidity of 55%, cut out to a sample length of 120 mm, and
In accordance with 6 / 2-1988, the number of reciprocations until cutting by bending was determined.

(Haze of Film) JIS K-671
The measurement was performed using a haze meter (Model 1001DP, manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with Example 4.

Example 1 100 parts by weight of cellulose triacetate having a degree of acetylation of 61.0% and a viscosity average degree of polymerization of 300, 400 parts of acetone and 10 parts by weight of TPP were mixed. At room temperature, cellulose triacetate is swollen,
28 kHz, 45 W with an ultrasonic irradiator manufactured by Ultrasonic Industry Co., Ltd.
/ Cm ² for 15 minutes. Next, the mixture was placed in a container having a double structure, and a water-ethylene glycol cooled mixture was introduced as a refrigerant into the outer jacket while slowly stirring the mixture. This allows the mixture in the inner container to reach -30 ° C.
Cooled down. The mixture was cooled for 30 minutes until it was cooled uniformly.

The refrigerant in the outer jacket of the container is discharged, and hot water is introduced into the jacket instead. Subsequently, the content was stirred, the temperature was raised to 30 ° C. over 40 minutes, the stirring was continued for 20 minutes, and the above cooling and heating operations were repeated twice. The dope was filtered using “Azumi Filter Paper No. 244” manufactured by Azumi Filter Paper Co., Ltd. to obtain Dope 1 and provided for film formation.

The liquid was sent to a die by a fixed-type gear pump, and was cast on a stainless steel belt being conveyed so that the dry film thickness became 120 μm. The first half was dried on a belt transferred with warm water at 50 ° C., and the web was dried by blowing air at 90 ° C. in the second half. The web is peeled off from the belt where the belt makes one rotation, and both ends of the web are held at 120 ° C. for 5 minutes while being held by clips, and then rolled at 140 ° C. for 20 minutes.
After drying for one minute, a film 1 was obtained. The residual solvent ratio of the film was 0.9%.

[Example 2] The ultrasonic irradiation in the swollen state was performed 3 times.
A dope 2 and a film 2 were prepared in the same manner as in Example 1 except that the time was 0 minutes and the repetition was eliminated.

Example 3 A dope 3 and a film 3 were prepared in the same manner as in Example 1 except that the irradiation of the ultrasonic wave in the swollen state was stopped, and the ultrasonic wave was irradiated during the cooling time to eliminate repetition.

Example 4 300 parts by weight of cellulose triacetate having an average acetylation degree of 61.0% and a viscosity average degree of polymerization of 300, 1200 parts by weight of acetone and 30 parts by weight of TPP were mixed in a container with a lid, and ultrasonically stirred for 15 minutes. Irradiation was performed. Next, the swollen cellulose triacetate mixture was applied to a thickness of 1
00μm aluminum container (internal volume 1000cc)
, And covered with aluminum foil so that no air remains, and sealed by caulking. The sealed container is packed in a rubber bag, and after lightly degassing, the rubber bag is sealed. This rubber bag was set in a rubber isostatic pressing device (manufactured by Kobe Steel) for ceramic molding, and 1000 kg / cm ² at 25 ° C.
Pressure for 2 hours. After pressurizing, return to atmospheric pressure, take out the aluminum container from the rubber bag, take off the lid of the aluminum container, transfer to the glass container, and transfer the dope to Azumi Filter Paper Co., Ltd.
Filtration was performed using “Azumi Filter Paper No. 244” to obtain a dope 4, and a film was formed in the same manner as in Example 1 to obtain a film 4.

Example 5 A dope 5 and a film 5 were obtained in the same manner as in Example 4 except that ultrasonic irradiation was performed for 30 minutes in the swollen state, and the heating time was set to 1 hour.

Example 6 A dope 6 and a film 6 were obtained in the same manner as in Example 4, except that irradiation of ultrasonic waves in the swollen state was stopped and ultrasonic waves were applied during pressurization.

Example 7 A dope 7 was prepared in the same manner as in Example 1 except that acetone was replaced with 2-methoxyethyl acetate.
And a film 7 were obtained.

Example 8 A dope 8 was prepared in the same manner as in Example 2 except that acetone was replaced with 2-methoxyethyl acetate.
And a film 8 were obtained.

Example 9 A dope 9 was prepared in the same manner as in Example 3 except that acetone was replaced with 2-methoxyethyl acetate.
And a film 9 were obtained.

Example 10 A dope 1 was prepared in the same manner as in Example 4 except that acetone was replaced with 2-methyletholacetate.
0 and film 10.

Example 11 A dope 1 was prepared in the same manner as in Example 5 except that acetone was replaced by 2-methylethrulacetate.
1 and a film 11 were obtained.

Example 12 A dope 1 was prepared in the same manner as in Example 6 except that acetone was replaced by 2-methylethrulacetate.
2 and film 12 were obtained.

Example 13 Dope 13 and film 1 were prepared in the same manner as in Example 1 except that acetone was replaced with methyl acetate.
3 was obtained.

Example 14 Dope 14 and film 1 were prepared in the same manner as in Example 2 except that acetone was replaced with methyl acetate.
4 was obtained.

Example 15 Dope 15 and film 1 were prepared in the same manner as in Example 3 except that methyl acetate was used instead of acetone.
5 was obtained.

Example 16 A dope 16 and a film 1 were prepared in the same manner as in Example 4 except that methyl acetate was used instead of acetone.
6 was obtained.

[Example 17] Dope 17 and film 1 were prepared in the same manner as in Example 5 except that methyl acetate was used instead of acetone.
7 was obtained.

Example 18 Dope 18 and film 1 were prepared in the same manner as in Example 6 except that methyl acetate was used instead of acetone.
8 was obtained.

Example 19 A dope 19 and a film 19 were obtained in the same manner as in Example 1 except that 400 parts by weight of acetone was replaced by 350 parts by weight of acetone and 50 parts by weight of 2,2,2-trifluoroethanol.

Example 20 A dope 20 and a film 20 were obtained in the same manner as in Example 2 except that 400 parts by weight of acetone was replaced by 350 parts by weight of acetone and 50 parts by weight of 2,2,2-trifluoroethanol.

Example 21 A dope 21 and a film 21 were obtained in the same manner as in Example 3 except that 400 parts by weight of acetone was replaced by 350 parts by weight of acetone and 50 parts by weight of 2,2,2-trifluoroethanol.

Example 22 A dope 22 and a film 22 were obtained in the same manner as in Example 4 except that 1200 parts by weight of acetone was replaced by 1050 parts by weight of acetone and 150 parts by weight of 2,2,2-trifluoroethanol.

Example 23 A dope 23 and a film 23 were obtained in the same manner as in Example 5, except that 1200 parts by weight of acetone was replaced by 1050 parts by weight of acetone and 150 parts by weight of 2,2,2-trifluoroethanol.

Example 24 A dope 24 and a film 24 were obtained in the same manner as in Example 6 except that 400 parts by weight of acetone was replaced by 350 parts by weight of acetone and 50 parts by weight of 2,2,2-trifluoroethanol.

Example 25 A dope was prepared in the same manner as in Example 1 except that 400 parts by weight of acetone was replaced with 300 parts by weight of acetone, 40 parts by weight of 2,2,2-trifluoroethanol, and 60 parts by weight of n-butanol. 25 and film 25
I got

Example 26 A dope was prepared in the same manner as in Example 2 except that 400 parts by weight of acetone was replaced with 300 parts by weight of acetone, 40 parts by weight of 2,2,2-trifluoroethanol, and 60 parts by weight of n-butanol. 26 and film 26
I got

Example 27 A dope was prepared in the same manner as in Example 3, except that 400 parts by weight of acetone was replaced by 300 parts by weight of acetone, 40 parts by weight of 2,2,2-trifluoroethanol, and 60 parts by weight of n-butanol. 27 and film 27
I got

Example 28 A dope 28 and a film 28 were obtained in the same manner as in Example 4 except that 1200 parts by weight of acetone was replaced by 1050 parts by weight of acetone and 150 parts by weight of 2,2,2-trifluoroethanol.

Example 29 A dope 29 and a film 29 were obtained in the same manner as in Example 5, except that 1200 parts by weight of acetone was replaced by 1050 parts by weight of acetone and 150 parts by weight of 2,2,2-trifluoroethanol.

Example 30 A dope was prepared in the same manner as in Example 6, except that 400 parts by weight of acetone was replaced by 300 parts by weight of acetone, 40 parts by weight of 2,2,2-trifluoroethanol, and 60 parts by weight of n-butanol. 30 and film 30
I got

Comparative Example 1 100 parts by weight of cellulose triacetate having a degree of acetylation of 61.0% and a viscosity average degree of polymerization of 300, 400 parts by weight of acetone and 10 parts by weight of TPP were mixed. At room temperature, the cellulose triacetate was in a swollen state. Next, the mixture was placed in a container having a double structure, and a water-ethylene glycol cooled mixture was introduced as a refrigerant into the outer jacket while slowly stirring the mixture. This allowed the mixture in the inner vessel to cool to -30C. The mixture was cooled for 30 minutes. Eject the refrigerant in the jacket outside the container, introduce warm water into the jacket instead, then stir the contents, raise to 30 ° C over 40 minutes, continue stirring for 20 minutes, cooling and heating above Was repeated twice, but no transparent dope was obtained. This cellulose triacetate solution was filtered through “Azumi Filter Paper No. 244” to obtain Comparative Dope 1, and Comparative Film 1 was prepared in the same manner as in Example 1.

Comparative Example 2 300 parts by weight of cellulose triacetate having an average acetylation degree of 61.0% and a viscosity average degree of polymerization of 310, 1200 parts by weight of acetone and 30 parts by weight of TPP,
The mixture was placed in a container with a lid and mixed. At room temperature, the cellulose triacetate was swollen in acetone without dissolving. Next, the swollen cellulose triacetate mixture was applied to a thickness of 1
00μm aluminum container (internal volume 1000cc)
, And covered with aluminum foil so that no air remains, and sealed by caulking. The sealed container is packed in a rubber bag, and after lightly degassing, the rubber bag is sealed. This rubber bag was set in a rubber isostatic pressing device (manufactured by Kobe Steel) for ceramic molding, and 1000 kg / cm ² at 25 ° C.
Pressure for 2 hours. After pressurization, the pressure was returned to the atmospheric pressure, the aluminum container was taken out of the rubber bag, the lid of the aluminum container was taken out, filtered in the same manner as in Example 1, and formed into a dope 2 and in the same manner as in Example 1, a comparative film 2 was formed. I got

Comparative Example 3 Comparative dope 3 and comparative film 3 were prepared in the same manner as in Comparative Example 1 except that 400 parts by weight of acetone was mixed with 385 parts by weight of acetone and 15 parts by weight of 1-butanol.

[Results] In either the cooling dissolution method or the pressure dissolution method,
It can be seen that the preparation of the cellulose triacetate solution subjected to ultrasonic irradiation of the present invention is more efficient than without irradiation. When the cellulose triacetate solution immediately after the preparation was filtered, it was found that the one subjected to ultrasonic irradiation was easier to filter than the non-irradiated one, and the turbidity and the amount of insoluble matter were different.
The combined use of a main solvent such as fluoroalcohol is better than the solubility of acetone alone, and the mechanical properties of the resulting film are also better. It turned out to be effective.

Tables 1 and 2 show the evaluation results of each of the obtained films.

[0150]

[Table 1]

[0151]

[Table 2]

[0152]

EFFECT OF THE INVENTION Cellulose triacetate can be efficiently dissolved without using a chlorine-based solvent, and excellent transparency and good filterability can be provided, and an excellent cellulose triacetate film using the same can be provided.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08K 5/04 C08K 5/04 C08L 1/12 C08L 1/12 // (C08K 5/04 5:05 5:15 5:07 5:10) B29K 1:00 B29L 7:00

Claims (24)

[Claims] An average degree of acetylation of 58.0% or more and 62.5%.
A step of cooling a mixture of the following cellulose triacetate and an organic solvent substantially free of chlorinated hydrocarbons to -100 to -10 ° C;
In preparing cellulose triacetate through a step of dissolving cellulose triacetate by heating to 0 ° C. and, if necessary, adding an additive to the solution and mixing, ultrasonic treatment is performed in any of the preparation processes. A method for preparing a cellulose triacetate solution, comprising: 2. The average acetylation degree is at least 58.0% and at least 62.5%.
A mixture of the following cellulose triacetate and an organic solvent substantially free of chlorinated hydrocarbons was added at 10 kg / c
A method for preparing a cellulose triacetate solution, which comprises irradiating with ultrasonic waves in any of the preparation steps when preparing by applying a pressure of m ^{2 to} 5000 kg / cm ² . 3. The method according to claim 2, wherein the ultrasonic irradiation is performed at a different oscillation frequency.
The method for preparing a cellulose triacetate solution according to claim 1 or 2, wherein the seeds are resonated. 4. The method according to claim 1, wherein the cellulose triacetate solution is acetone, 1,3-dioxolan, 1,4-dioxane,
The method for preparing a cellulose triacetate solution according to any one of claims 1 to 3, further comprising a main solvent selected from methyl acetate, methyl acetoacetate, 2-methoxyethyl acetate, fluoroalcohol, and ethyl formate. 5. The method according to claim 1, wherein the cellulose triacetate is 220.
The method for preparing a cellulose triacetate solution according to any one of claims 1 to 4, wherein the cellulose triacetate solution has a viscosity average degree of polymerization of 500 or more and 500 or less. 6. The cellulose triacetate solution having a cellulose triacetate concentration of 10% by weight to 5% by weight.
The method for preparing a cellulose triacetate solution according to any one of claims 1 to 5, wherein the amount is 0% by weight. 7. The cellulose triacetate solution,
The method for preparing a cellulose triacetate solution according to any one of claims 1 to 6, wherein the plasticizer is contained in an amount of 5% by weight or more and 30% by weight or less based on the cellulose triacetate. 8. The method for preparing a cellulose triacetate solution according to claim 2, wherein the pressure is increased by a hydrostatic pressure method. 9. An average degree of acetylation of 58.0% or more and 62.5%.
The following cellulose triacetate, and a mixture of organic solvents substantially free of chlorinated hydrocarbons from -100 to-
Cooling to 10 ° C., cooling the cooled mixture from 0 to 50
Casting the cellulose triacetate solution prepared on the support through a step of dissolving the cellulose triacetate by heating to a temperature of ℃, and a step of adding and mixing additives as needed, and evaporating the solvent. A method for producing a cellulose triacetate film, which comprises irradiating ultrasonic waves in any of the steps of preparing the cellulose triacetate solution in forming a cellulose triacetate film through a step of drying the film. 10. An average acetylation degree of 58.0% or more and 62.5% or more.
% Or less of a mixture of cellulose triacetate and an organic solvent substantially free of chlorinated hydrocarbons.
In forming a cellulose triacetate film through a step of casting a cellulose triacetate solution prepared by applying a pressure of not less than cm ^{2 and not} more than 5000 kg / cm ² on a support and a step of evaporating a solvent and drying the film, A method for producing a cellulose triacetate film, which comprises irradiating ultrasonic waves in any of the steps of preparing a triacetate solution. 11. The ultrasonic irradiation according to claim 9, wherein two kinds of oscillation frequencies different from each other are resonated.
Or the method for producing a cellulose triacetate film according to 10. 12. The cellulose triacetate solution contains a main solvent selected from acetone, 1,3-dioxolan, 1,4-dioxane, methyl acetate, methyl acetoacetate, 2-methoxyethyl acetate, fluoroalcohol, and ethyl formate. The method for producing a cellulose triacetate film according to any one of claims 9 to 11, wherein: 13. The method according to claim 12, wherein the cellulose triacetate is 22.
The method for producing a cellulose triacetate film according to any one of claims 9 to 12, having a viscosity average degree of polymerization of 0 or more and 500 or less. 14. The method for producing a cellulose triacetate film according to claim 9, wherein the concentration of the cellulose triacetate in the cellulose triacetate solution is 10% by weight to 50% by weight. 15. The cellulose triacetate film according to claim 9, wherein the cellulose triacetate solution contains a plasticizer in an amount of 5% by weight or more and 30% by weight or less based on cellulose triacetate. Manufacturing method. 16. The method for producing a cellulose triacetate film according to claim 10, wherein the pressure is increased by a hydrostatic pressure method. 17. An average degree of acetylation of 58.0% or more and 62.5% or more.
% Or less of a mixture of cellulose triacetate and an organic solvent substantially containing no chlorinated hydrocarbons, and the cooled mixture is heated to 0 to 50 ° C. to cool the cellulose triacetate. Dissolving, and, if necessary, casting the cellulose triacetate solution on a support through a step of adding and mixing additives to the solution, and a step of evaporating the solvent and drying the film. In forming a cellulose triacetate film, a cellulose triacetate film obtained by performing ultrasonic treatment in any of the preparation processes and forming a film using a cellulose triacetate solution. 18. The average degree of acetylation is 58.0% or more and 62.5 or more.
% Or less of a mixture of cellulose triacetate and an organic solvent substantially free of chlorinated hydrocarbons.
The step of casting a cellulose triacetate solution prepared by applying a pressure of not less than cm ^{2 and not} more than 5000 kg / cm ² onto a support and the step of evaporating the solvent and drying the film form a cellulose triacetate film. A cellulose triacetate film formed by using a cellulose triacetate solution subjected to ultrasonic irradiation in any one of the processes. 19. The ultrasonic irradiation according to claim 1, wherein two kinds of oscillation frequencies different from each other are resonated.
19. The cellulose triacetate film according to 7 or 18. 20. The cellulose triacetate solution contains a main solvent selected from acetone, 1,3-dioxolan, 1,4-dioxane, methyl acetate, methyl acetoacetate, 2-methoxyethyl acetate, fluoroalcohol, and ethyl formate. The cellulose triacetate film according to any one of claims 17 to 19, wherein: 21. The cellulose triacetate comprising 22
21. The cellulose triacetate film according to claim 17, which has a viscosity average polymerization degree of 0 or more and 500 or less. 22. The cellulose triacetate solution according to claim 17, wherein the concentration of cellulose triacetate is 10% by weight to 50% by weight.
The cellulose triacetate film according to any one of the above. 23. The cellulose triacetate film according to claim 17, wherein the cellulose triacetate solution contains a plasticizer in an amount of 5% by weight or more and 30% by weight or less based on the cellulose triacetate. . 24. The cellulose triacetate film according to claim 18, which is pressurized by a hydrostatic pressure method.