JP2003268001A - Cellulose ester and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a cellulose ester having high releasability from a support and high spinnability and to obtain a method for producing the cellulose ester and to obtain the molded product of the compound. <P>SOLUTION: The carboxyl groups of a raw material cellulose or a cellulose ester produced by acylation of the cellulose are blocked to produce the cellulose ester reduced in carboxy group concentration. The carboxy group concentration of the cellulose ester is e.g. ≤1 meq/100 g expressed in terms of cellulose. The molded product such as a film or a fiber can be formed by using the cellulose ester. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cellulose ester useful for forming a film (a polarizing plate protective film, a color filter, a film of a photographic light-sensitive material, etc.) and a fiber (a tobacco filter, a textile fiber, etc.), and a cellulose ester thereof. It relates to a manufacturing method.

[0002]

2. Description of the Related Art Cellulose ester film is a solution (dope) prepared by dissolving a solvent and various additives as necessary in a cellulose ester produced by esterifying cellulose such as softwood pulp, hardwood pulp and cotton linter pulp. ) Is cast on a support and the film is peeled from the support. In this method, if the releasability of the film from the support is poor, the surface smoothness of the film will be reduced, and the production rate will not be increased, and the productivity will be reduced.

Japanese Unexamined Patent Publication No. 10-316701 describes that the use of cellulose acetate prepared from hardwood pulp as a raw material reduces the releasability from the support.

On the other hand, the cellulose ester fiber is produced by extruding a solution (dope) containing the same cellulose ester as described above from a spinneret having small holes and spinning it dry or wet. If the spinnability of the dope is poor, the spun fiber is likely to be broken, which lowers the production speed and productivity and also the quality.

Japanese Unexamined Patent Publication No. 10-316701 discloses that
(1) A method in which at least a part of the carboxyl groups bonded to cellulose acetate and / or hemicellulose acetate is present in an acid form, (2) an acid dissociation index pKa in an aqueous solution of cellulose acetate is 1.93 to 4.
A method of containing at least one acid selected from the group consisting of 50, at least one selected from the alkali metal salt of this acid and the alkaline earth metal salt of said acid, and (3) the addition of alkali metal and alkaline earth metal in 1 g of cellulose acetate. A method is disclosed in which the total content is not less than the effective amount and not more than 5.5 × 10 ⁻⁶ equivalent (ion equivalent). But,
Since all of these methods define the ionic state of cellulose acetate, there is a possibility that the method of using cellulose acetate may be greatly limited, and that the quality of the molded product may be affected. For example, the pKa1.
Inclusion of 93 to 4.50 acid may cause corrosion of the production equipment or decomposition of cellulose acetate.

[0006]

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a cellulose ester having a high releasability from a support and a high spinnability, a method for producing the same and a molded article.

Another object of the present invention is to provide a cellulose ester capable of efficiently producing a film or fiber by using a dope of cellulose ester, a method for producing the same, and a molded article.

Still another object of the present invention is to provide a cellulose ester which can be used under a wide range of conditions and does not impair the quality and stability, a method for producing the same and a molded article.

[0009]

Means for Solving the Problems As a result of intensive studies for achieving the above-mentioned object, the present inventors have found that when the carboxyl group content in cellulose or cellulose ester is reduced by sealing or derivatization, peeling of the film occurs. It was found that the spinnability and the spinnability of the dope can be greatly improved, and the present invention has been completed.

That is, the cellulose ester of the present invention has a reduced carboxyl group content due to sealing.
The carboxyl group content of the cellulose ester is about 1 meq / 100 g or less (for example, 0.4 meq / 100 g or less) of cellulose in terms of cellulose. The cellulose ester may have a mannose content of 0.4 mol% or more and a carboxyl group content of about 1.1 meq / 100 g or less in terms of cellulose. The cellulose ester has a mannose content of 0.
It is more than 1 mol% and less than 0.4 mol% and the carboxyl group content is 0.8 meq / 100 in terms of cellulose.
It may be about g or less. Further, the cellulose ester has a mannose content of 0.1 mol% or less,
And the carboxyl group content is 1.1 me in terms of cellulose.
It may be about q / 100 g or less. The cellulose ester may have a ratio (molar ratio) of xylose content to mannose content of less than 3 and a carboxyl group content of about 1.1 meq / 100 g or less in terms of cellulose. In addition, the cellulose ester is a ratio (molar ratio) of xylose content to mannose content.
May be 3 or more, and the carboxyl group content may be about 0.8 meq / 100 g or less in terms of cellulose. The cellulose ester has a carboxyl group content of 1 meq / 100 g or less due to sealing (for example, 0.7 m
eq / 100 g or less).

The present invention also includes a molded product (for example, a film or a fiber) formed of the above-mentioned cellulose ester.

The present invention relates to a method for acylating cellulose to produce a cellulose ester having a reduced carboxyl group content, wherein the carboxyl group of the cellulose or the cellulose ester produced by acylation is blocked to form a carboxyl group. Also included is a method of making a cellulose ester having a reduced group content.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION [Cellulose Ester] Cellulose ester is usually produced by esterifying cellulose such as wood pulp (softwood pulp, hardwood pulp) and cotton linter pulp. These pulps usually contain foreign components such as hemicellulose. Therefore, in this specification, the term "cellulose" means
It is used in the sense that it also contains different components such as hemicellulose.

It is known that cellulose as a raw material usually contains some carboxyl groups in a state of being bonded to cellulose molecules and / or hemicellulose molecules. This carboxyl group content is TAPPI St
It can be quantified by various methods such as andard T237 om-83. The content of the carboxyl group in the pulp (cellulose) specified in the present invention depends on this TAPPI St.
It is the value quantified by andard T237 om-83. The cellulose containing a carboxyl group does not include cellulose having a polyvalent carboxylic acid introduced therein.

When the carboxyl group content of the cellulose for cellulose acetate is measured by the above measuring method, it is 1.1 to 1.6 meq / 100 for hardwood pulp.
g, 1.8 to 2.8 meq / 100 g for softwood pulp
Is. In addition, the literature (A. Isogai et al., Journal of the Textile Society, 48 (1
1), 649 (1992); Okada et al., Paper and Paper Co., Ltd., 28 (2), 59 (1974)) describes linter pulp having a carboxyl group content of 1.4 meq / 100 g. In the present invention, the carboxyl group content of cellulose as a raw material is not particularly limited, but cellulose having a carboxyl content of about 0.01 to 3 meq / 100 g is usually used.

The cellulose ester can be produced by a conventional esterification method in which cellulose is reacted with an acylating agent, and can be produced through a saponification or aging step if necessary. Cellulose ester is usually prepared by activating pulp (cellulose) with an activating agent (activating step), and then preparing the ester (triester, etc.) with an acylating agent using a catalyst such as sulfuric acid (acylating step). ), Saponification (hydrolysis) and aging to adjust the degree of esterification (saponification and aging step). In the case of cellulose acetate, for example, sulfuric acid catalyst method, acetic acid method,
It can be produced by a conventional method such as the methylene chloride method.

In this method, the activation step can be carried out by treating the pulp (cellulose) by, for example, spraying an activator or dipping in an activator. , Pulp (cellulose) 100
10 to 100 parts by weight, preferably 20 to 100 parts by weight
The amount is 80 parts by weight, more preferably about 30 to 60 parts by weight. In the case of cellulose acetate, for example, acetic acid or hydrous acetic acid can be used as the activator.

The proportion of the acylating agent in the acylation step can be selected within a range that provides a desired degree of acylation (degree of acetylation etc.), and for example, 230 to 300 parts by weight relative to 100 parts by weight of pulp (cellulose), Preferably 240-290
Parts by weight, more preferably about 250 to 280 parts by weight. In the case of cellulose acetate, acetic anhydride or the like can be used as the acylating agent.

Sulfuric acid is usually used as the acylation or aging catalyst. The amount of sulfuric acid used is usually cellulose 1
The amount is 0.5 to 15 parts by weight, preferably 5 to 15 parts by weight, and more preferably 5 to 10 parts by weight with respect to 00 parts by weight. The temperature for saponification and aging is 40 to 160 ° C.
The temperature can be selected from the range of, for example, about 50 to 70 ° C.

Further, in order to neutralize the residual sulfuric acid,
It may be treated with alkali.

The types of cellulose ester include, for example, organic acid esters [cellulose C _2-6 carboxylic acid esters such as cellulose acetate (cellulose acetate), cellulose propionate and cellulose butyrate], mixed esters (cellulose acetate Cellulose di C _2-6 carboxylic acid esters such as pionate and cellulose acetate butyrate), grafts (such as polycaprolactone-grafted cellulose acetate), cellulose ester ethers (acetyl methyl cellulose, acetyl ethyl cellulose, C such as acetyl propyl cellulose) _{2- 6} Acyl cellulose C _1-6 alkyl ether, C _2-6 acyl cellulose such as acetyl hydroxyethyl cellulose, acetyl hydroxypropyl cellulose, etc. Hydroxy C _2-6 alkyl Examples thereof include kill ethers), inorganic acid esters (cellulose nitrate, cellulose sulfate, cellulose phosphate, etc.), organic acid / inorganic acid mixed esters (cellulose nitrate acetate, etc.) and the like. Among these cellulose esters, esters containing an organic acid, particularly cellulose acetate, are preferable.

The average degree of substitution of the acyl group of the cellulose ester is 1 to 3, preferably 1.5 to 3 (for example, 1.7).
~ 3), more preferably 1.8 to 3 (e.g., 2 to 3).
It is about 3). In the case of cellulose acetate, the average degree of acetylation can be selected from the range of about 30 to 62.5%, and
Average degree of acetylation 43.7-62.5% (average degree of substitution of acetyl groups 1.7-3), preferably 45-62.5% (average degree of substitution 1.8-3), more preferably 48- 62.5
% (Average degree of substitution 2-3).

The degree of polymerization of the cellulose ester is not particularly limited, and the viscosity average degree of polymerization is 200 to 400, preferably 2
It is about 50 to 400, more preferably about 270 to 350.

[Method for Reducing Carboxyl Group Content] In the present invention, the carboxyl group in the raw material cellulose and / or the cellulose ester produced by acylation is derivatized (capped or inactivated) to obtain the carboxyl group in the cellulose ester. The carboxyl group content (concentration) is reduced.

The type of cellulose is not particularly limited, but cellulose having a small content of carboxyl group (for example, 0 to 1 meq / 100 g, particularly 0.001 to 1) is preferable because the sealing or inactivation of the carboxyl group is slight.
1 meq / 100 g) may be used. In general, cotton linter pulp is preferable because it tends to have a low carboxyl group content, but it is more expensive than wood pulp. Therefore, it is preferable to use inexpensive cellulose having a low carboxyl group content.

The blocking or derivatization (inactivation) of the carboxyl group can be performed on the raw material cellulose and / or the cellulose ester produced by acylation.
That is, the encapsulation or derivatization may be performed in any step of the cellulose ester production step, the cellulose ester production step, and the cellulose ester molding step (for example, a film or fiber production step). When encapsulation or derivatization is performed prior to the molding step, the cellulose ester can be molded into a film, fiber or the like by a general method.
On the other hand, when the sealing or derivatization is performed in the molding step, it is also possible to add a reactant for a carboxyl group to cellulose ester and mold it into a film, a fiber or the like by the above method, and if necessary. After providing the refining step by molding, the molding may be performed. The formation or inactivation of the carboxyl group does not include the formation of a metal salt of the carboxyl group.

The method of capping or derivatizing with a reactant for the carboxyl group is not particularly limited, and examples thereof include diazo compounds [diazo C _1-4 alkanes (diazomethane, diazoethane, etc.) and tri C _1-4 alkylsilyldiazo. C _1-4 alkanes (such as trimethylsilyl diazomethane) substituted by well as good diazoalkane] C _1-4 alkyl (especially methyl) ester of such, oxazoline compound (oxazoline or 2-methyl oxazoline, 2- C _1-4 alkyloxazolines such as ethyloxazoline)
Amide esterification with alcohols (methanol,
Esterification with C _1-4 alkyl alcohols such as ethanol and isopropanol, epoxy compounds (C _2-4 alkylene oxides such as ethylene oxide and propylene oxide, aryl glycidyl ethers such as phenyl glycidyl ether, C such as n-butyl glycidyl ether) _1-6 alkyl glycidyl ether, versatic acid glycidyl ether, etc.), esterification with aziridine compound (aziridine, etc.), mono- or di-C _1-4 alkyl such as ammonia and amines (methylamine, ethylamine, dimethylamine, etc.) Amines,
Known methods such as amidation with alkanolamines such as ethanolamine) and amidation with isocyanate compounds can be used. In the amidation with the ammonia or amines, a carbodiimide compound may be used as the case requires. Further, an ionic-bonding reactive agent (ion-pair reagent) may be used as long as it is a reactive agent that forms a strong ion pair with a carboxyl group and inhibits bond formation with a metal surface. Examples of such an ion pair reagent include ammonia and amines (preferably quaternary ammonium ion salts, amidines, guanidines, etc.) and the like.

Among these reactants, cellulose and / or
Alternatively, there are compounds that react not only with the carboxyl group in the cellulose ester but also with the hydroxyl group. When the influence on the quality of cellulose ester is concerned, a reactant that selectively reacts with a carboxyl group (for example, methyl esterification with diazomethane or trimethylsilyldiazomethane, amide esterification with an oxazoline compound such as 2-methyloxazoline). Or amidation with ammonia or amines, formation of ionic bond, etc.) is preferably used. The carboxyl group forms a metal salt,
When the derivatization reaction is difficult, it is preferable to carry out an acid treatment as necessary to at least partially convert it into an acid form before the derivatization.

The ratio of the above-mentioned reactant is not particularly limited, but is usually used in an excess amount with respect to the carboxyl group contained in the raw material cellulose or the cellulose ester produced by acylation. For example, the carboxyl group 1
The amount of the reactant is 0.3 to 100 mol, preferably 0.5 to 50 mol, and more preferably 1 to 10 mol (for example, 3 to 10 mol). It is easy to complete the derivatization reaction by using the reactant in excess of the carboxyl group.

The derivatization reaction may be carried out in the presence or absence of a solvent. The solvent is not particularly limited as long as it does not inhibit the reaction, and examples thereof include halogenated hydrocarbons (methylene chloride, ethylene chloride, etc.), alcohols (C such as methanol, ethanol, isopropanol, etc.).
_1-4 alkyl alcohol), ketones (acetone, methyl ethyl ketone, etc.), esters (ethyl formate, methyl acetate, etc.), ethers (1,4-dioxane, tetrahydrofuran, etc.), cellosolves (methyl cellosolve, ethyl cellosolve, etc.) , Cellosolve acetates (methyl cellosolve acetate, ethyl cellosolve acetate, etc.), and mixtures thereof.

The temperature in the derivatization reaction is not particularly limited and is, for example, 0 to 150 ° C., preferably 5 to 100.
C., more preferably about 10 to 75.degree. C., and depending on the reactant, the reaction may be performed at room temperature (for example, about 15 to 30.degree. C.). Further, the reactant may be introduced into the reaction system all at once, may be introduced continuously, or may be introduced intermittently or intermittently.

The inactivated cellulose ester is used as a material for a support for film production and a die for fiber production (for example,
It is preferred that they do not form strong interactions with metals such as stainless steel). Therefore, as the reactive agent for the carboxyl group, a compound that introduces a structure that does not form a hydrogen bond or an ionic bond with the metal material (for example, a compound that blocks the terminal with an alkyl group) is preferable. In addition, it is preferable to avoid a reactive agent that causes insolubilization by cross-linking the molecules of the cellulose ester.

The carboxyl group content (concentration) of the blocked or derivatized cellulose ester is not particularly limited as long as the film peeling property and / or the spinnability is improved, but in terms of cellulose, 1 meq / 100 g or less. (Eg, 0.001 to 1 meq / 100 g), preferably 0.7 meq / 100 g or less (eg, 0.001
~ 0.7 meq / 100 g), more preferably 0.4
meq / 100g or less (for example, 0.001 to 0.4 m
eq / 100 g), and particularly to the extent that it does not substantially contain a carboxyl group (for example, 0.2 meq / 10
0 g or less, especially 0.001 to 0.1 meq / 100 g)
Is preferred.

Further, as a result of further detailed study by the present inventors, the preferable content of the carboxyl group in the encapsulated or derivatized cellulose ester depends on the mannose content or the ratio of the xylose content to the mannose content. I found that I could do it.

That is, the carboxyl group content of the cellulose ester is 1.1 meq / 100 in terms of cellulose when the mannose content is 0.4 mol% or more.
g or less (for example, 0.001 to 1.1 meq / 100
g), preferably 0.8 meq / 100 g or less (eg 0.001 to 0.8 meq / 100 g), more preferably 0.5 meq / 100 g or less (eg 0.0.
01 to 0.5 meq / 100 g), and in particular, substantially no carboxyl group (for example, 0.
2 meq / 100 g or less, particularly 0.001 to 0.1 me
q / 100 g) is preferred.

When the mannose content is more than 0.1 mol% and less than 0.4 mol%, the carboxyl group content of the cellulose ester is 0.8 meq in terms of cellulose.
/ 100 g or less (for example, 0.001 to 0.8 meq /
100 g), preferably 0.6 meq / 100 g or less (for example, 0.001 to 0.6 meq / 100 g), more preferably 0.4 meq / 100 g or less (for example,
0.001 to 0.4 meq / 100 g), and in particular, substantially no carboxyl group (for example, 0.2 meq / 100 g or less, particularly 0.001 to
0.1 meq / 100 g) is preferred.

When the mannose content is 0.1 mol% or less, the carboxyl group content of the cellulose ester is
In terms of cellulose, 1.1 meq / 100 g or less (for example, 0.001 to 1.1 meq / 100 g), preferably 0.6 meq / 100 g or less (for example, 0.001 to 0.001
0.6 meq / 100 g), more preferably 0.3 m
eq / 100 g or less (for example, 0.001 to 0.3 me
q / 100 g), and particularly to the extent that it does not substantially contain a carboxyl group (for example, 0.2 meq / 100).
g or less, particularly 0.001 to 0.1 meq / 100 g) is preferable.

When the ratio (molar ratio) of the xylose content to the mannose content is less than 3, the carboxyl group content of the cellulose ester is calculated in terms of cellulose.
1.1 meq / 100g or less (for example, 0.001-
1.1 meq / 100 g), preferably 0.8 meq /
100 g or less (for example, 0.001 to 0.8 meq / 1
00 g), more preferably about 0.5 meq / 100 g or less (for example, 0.001 to 0.5 meq / 100 g), and particularly to the extent that substantially no carboxyl group is contained (for example, 0.2 meq / 100 g or less, Especially 0.
001 to 0.1 meq / 100 g) is preferable.

When the ratio (molar ratio) of the xylose content to the mannose content is 3 or more, the carboxyl group content of the cellulose ester is 0.8 in terms of cellulose.
meq / 100g or less (for example, 0.001 to 0.8 m
eq / 100g), preferably 0.6 meq / 100g
Below (for example, 0.001 to 0.6 meq / 100
g), more preferably about 0.4 meq / 100 g or less (for example, 0.001 to 0.4 meq / 100 g), and particularly to the extent that substantially no carboxyl group is contained (for example, 0.2 meq / 100 g or less, Especially 0.0
01 to 0.1 meq / 100 g) is preferable.

When the encapsulated or derivatized cellulose (pulp) is used as a raw material for the cellulose ester, the carboxyl group content of the encapsulated or derivatized cellulose (pulp) depends on the film peelability and / or the spinnability. Is not particularly limited as long as it is within the range of 1 me
q / 100g or less (for example, 0.001 to 1 meq / 1
00g), preferably 0.7 meq / 100g or less (e.g. 0.001 to 0.7 meq / 100g), more preferably 0.4 meq / 100g or less (e.g.
001 to 0.4 meq / 100 g), and in particular,
To the extent that it does not substantially contain a carboxyl group (for example,
0.2 meq / 100 g or less, particularly 0.001 to 0.1
meq / 100 g) is preferred.

More specifically, the preferred content of carboxyl groups in the encapsulated or derivatized cellulose is 1 meq / 100 g or less (for example, 0.
001 to 1 meq / 100 g), preferably 0.8 me
q / 100g or less (for example, 0.001 to 0.8 meq
/ 100 g), more preferably 0.6 meq / 100
g or less (for example, 0.001 to 0.6 meq / 100
It is about g), and particularly preferably to the extent that it does not substantially contain a carboxyl group (for example, 0.2 meq / 100 g or less, particularly 0.001 to 0.1 meq / 100 g).

The carboxyl group content of softwood pulp is
1.5 meq / 100 g or less (for example, 0.001 to
1.5 meq / 100 g), preferably 1 meq / 10
0 g or less (for example, 0.001 to 1 meq / 100
g), more preferably about 0.6 meq / 100 g or less (for example, 0.001 to 0.6 meq / 100 g), and in particular, substantially no carboxyl group (for example, 0.2 meq / 100 g or less, Especially 0.0
01 to 0.1 meq / 100 g) is preferable.

The carboxyl group content of cotton linter pulp is 1 meq / 100 g or less (for example, 0.001).
~ 1 meq / 100g), preferably 0.6 meq / 1
00g or less (for example, 0.001 to 0.6 meq / 10
0 g), more preferably about 0.3 meq / 100 g or less (for example, 0.001 to 0.3 meq / 100 g), and in particular, substantially no carboxyl group (for example, 0.2 meq / 100 g or less, Especially 0.0
01 to 0.1 meq / 100 g) is preferable.

[Cellulose Ester Molded Product] The cellulose ester of the present invention can be used to prepare a solution (dope) prepared by adding a solvent and various additives as necessary to prepare a film or fiber by a conventional method. Useful to do.

Examples of the solvent include halogenated hydrocarbons (methylene chloride, ethylene chloride, etc.), ketones (C _3-6 dialkyl ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl propyl ketone, methyl butyl ketone). , Cyclohexanone, etc., esters (formic acid C _1-4 alkyl ester such as ethyl formate, acetic acid C such as methyl acetate, ethyl acetate, butyl acetate)
_1-4 alkyl ester, ethyl propionate, ethyl lactate, etc.), ethers (cyclic or chain C _4-6 ether such as 1,4-dioxane, tetrahydrofuran, tetrahydropyran, diethyl ether, diisopropyl ether, dimethoxyethane), Examples thereof include cellosolves (C _1-4 alkyl cellosolve such as methyl cellosolve, ethyl cellosolve, butyl cellosolve), cellosolve acetates (C _1-4 alkyl cellosolve acetate such as methyl cellosolve acetate, ethyl cellosolve acetate), and mixtures thereof. .

The proportion of the solvent can be selected within a range that does not impair the casting property, the spinnability, the handling property, etc. in the film forming,
For example, 15 parts to 100 parts by weight of cellulose ester
0 to 1000 parts by weight (concentration of cellulose ester = about 1
0 to 40% by weight), preferably 200 to 900 parts by weight (concentration of cellulose ester = about 10 to 30% by weight)
And the content of cellulose ester is usually 10
It is about 25% by weight (for example, 10 to 20% by weight).

The dope thus obtained is useful for film formation by the casting method. In film formation, for example, in the case of cellulose acetate, cellulose di- or triacetate (particularly cellulose triacetate) is used. The film by the casting method is usually obtained by casting the dope on a support, partially drying it, peeling it from the support, and then drying.

As the support, a conventional support such as, for example,
A mirror-finished metal support (eg, stainless steel support) or the like can be used.

Since the cellulose ester of the present invention has high releasability (release property) from the support, the semi-dried film can be smoothly released from the support, and a cellulose ester film having high surface smoothness can be obtained. You can Therefore,
The production speed can be increased and the productivity can be improved. Therefore, the method of using the dope of the present invention is useful as a method of improving the releasability of the film from the support. Further, the cellulose ester film of the present invention has excellent optical characteristics.

The thickness of the cellulose ester film thus obtained is, for example, 5 to 50 depending on the use.
The thickness is 0 μm, preferably 10 to 200 μm, more preferably 20 to 150 μm (particularly 40 to 150 μm).

The cellulose ester film of the present invention comprises
It is useful as a photographic film, a protective film for a polarizing plate, a film for a color filter, and since it is excellent in releasability from a support, it is particularly useful as a thin optical film by a spin coding method or the like.

The cellulose ester of the present invention has low adhesion to the spinneret for fiber production, and is therefore excellent in spinnability. When fibers are produced by the spinning method, for example, in the case of cellulose acetate, cellulose di- or triacetate is usually used. The spinning method can be obtained by a conventional method, for example, by spinning the dope in a dry or wet manner from a spinneret having a large number of pores, and may be stretched if necessary. By spinning the dope of the present invention, it is possible to prevent clogging of the spinneret pores and yarn breakage for a long period of time. Further, as a result, high quality fibers can be manufactured. Therefore, the method of using the dope of the present invention is useful as a method of improving spinnability.

The cellulose ester fiber of the present invention is useful, for example, as a tobacco filter or a fiber for clothing.

The cellulose ester is a conventional additive such as a deterioration inhibitor (eg, antioxidant, ultraviolet absorber, peroxide decomposer, radical inhibitor, metal deactivator, acid scavenger, etc.), Crystal nucleating agent, inorganic powder (for example,
Diatomaceous earth, calcium carbonate, titanium oxide, etc.), a heat stabilizer, a flame retardant, a coloring agent and the like.

The cellulose ester and dope of the present invention are
Plasticizers such as triphenyl phosphate (TP
P), phosphates such as tricresyl phosphate (TCP), dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP),
Phthalates such as dioctyl phthalate (DOP) and di-2-ethylhexyl phthalate (DEHP), fatty acids such as butyl oleate, methylacetyl ricinoleate and dibutyl sebacate, citrates such as acetyltributyl citrate (OACTB) , Trimellitic acid ester and the like may be contained. These plasticizers can be used alone or in combination of two or more.

In the production of the cellulose ester film or fiber of the present invention, even if the cellulose ester of the present invention is used in combination with a conventional cellulose ester, the releasability from the support or the spinnability can be improved. . For example, in the production of a film, a cellulose ester having high peelability of the present invention and a conventional cellulose ester are laminated, and a layer composed of the cellulose ester of the present invention is brought into contact with a support to cast a two-layer or multi-layer film. It is also possible to do so. Further, in spinning, the core layer may be composed of a conventional cellulose ester and the outer layer may be composed of the cellulose ester of the present invention.

[0057]

INDUSTRIAL APPLICABILITY According to the present invention, a cellulose ester having high releasability from the support and high spinnability can be produced. Further, it can be used under a wide range of conditions, and a cellulose ester can be produced without impairing quality or stability. Furthermore, the use of the cellulose ester dope enables efficient production of a film or fiber. The obtained cellulose ester film or fiber is useful for optical applications and the like.

[0058]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited by these examples. The carboxyl group content, the degree of acetylation, the degree of polymerization, and the peelability were measured by the following methods.

[Carboxyl Group Content] (Carboxyl Group Content in Cellulose) The carboxyl group content in cellulose is TAPPI Standard T237 om.
It was measured by -83.

(Carboxyl Group Content in Cellulose Ester) Dry cellulose ester was added to a mixed solution of methylene chloride and methanol (methylene chloride / methanol = 9/1 (weight ratio)) so that the concentration of cellulose ester was 5% by weight. Dissolve in. About 10 g of the above solution (content of cellulose ester of about 0.5 g) is added to methanol to precipitate and regenerate the cellulose ester. The solvent in the obtained cellulose ester precipitate was washed and replaced with methanol,
Then, after being replaced by washing with water, the mixture was lightly filtered through a glass filter, and the total weight of the collected precipitate and the attached water was A (g).
To measure. To this water-wet cellulose ester,
14.5 g of methylene blue chloride aqueous solution having a concentration of 420 ppm by weight and borate buffer solution 2 adjusted to pH = 8.5
0 g was added and the mixture was stirred at 20 to 25 ° C. for 2 hours to adsorb methylene blue to the carboxyl group of cellulose ester. The cellulose ester is filtered off using a glass filter and the filtrate is collected. 0.1N to 3 g of the filtrate
-Add 3 g of hydrochloric acid and 36 g of water. 664n of this solution
The peak absorbance around m is measured. On the other hand, the absorbance of a solution adjusted to various methylene blue chloride concentrations without adding a cellulose ester was measured, and the relationship between the absorbance and the methylene blue chloride concentration was investigated. From the obtained relational expression, the methylene blue chloride concentration B of the diluted filtrate was measured.
(Weight ppm) is calculated. Further, the cellulose ester having methylene blue chloride adsorbed thereon is washed with water three times and then vacuum dried to measure the absolute dry weight C (g), and the carboxyl group content in the cellulose ester is calculated from the following formula.

Carboxyl group content (meq / 100 g cellulose ester) = [6090-14 × B × (34.5 + AC)] / (3739 ×
C) In addition, in order to facilitate comparison between the cellulose ester having different kinds of substituents and different degrees of substitution, the carboxyl group content in the cellulose ester is referred to as cellulose in the present specification. That is, the content of the carboxyl group in the cellulose ester was based on the amount of the cellulose ester that produces 100 g of cellulose when completely hydrolyzed. For example, in the case of cellulose triacetate (degree of substitution 3), 1
Hydrolysis of 00 g yields 56.25 g of cellulose. Therefore, the carboxyl group content (calculated as cellulose ester: meq / 100 g) determined according to the above formula should be 1
The value obtained by multiplying 00 / 56.25 = 1.778 times is the carboxyl group content of cellulose acetate (degree of substitution 3) (in terms of cellulose: meq / 100 g).

[Mannose content and xylose content] Cellulose ester was cooled with 72% by weight sulfuric acid in an ice water bath for 4 hours, then diluted with 6% by weight sulfuric acid to 110 ° C.
And hydrolyze for 3 hours. This was neutralized with barium carbonate, and the filtrate obtained by filtration was analyzed by liquid chromatography using a sugar analysis system manufactured by Dionex Co., and the ratio (mol%) of each component to the total amount of glucose, mannose and xylose was calculated. To do.

[Acetification degree] The degree of acetylation means the weight percentage of bound acetic acid per unit weight, and was measured as follows. 1.9 g of dried cellulose acetate was precisely weighed, and a mixed solution of acetone and dimethyl sulfoxide (volume ratio 4:
1) After dissolving in 150 mL, 30 mL of 1N-sodium hydroxide aqueous solution is added, and saponification is carried out at 25 ° C. for 2 hours.
Phenolphthalein is added as an indicator, and excess sodium hydroxide is titrated with 1N-sulfuric acid (concentration factor: F). In addition, a blank test is performed in the same manner as above, and the acetylation degree is calculated according to the following formula.

Acetylation degree (%) = {6.5 × (B−A) × F} / W (In the formula, A is the titration amount (mL) of 1N-sulfuric acid of the sample,
Is the titration amount (mL) of 1N-sulfuric acid in the blank test, F is the concentration factor of 1N-sulfuric acid, and W is the weight of the sample).

[Polymerization degree] The polymerization degree was measured as follows. The dried sample was added to a mixed solution of dichloromethane / methanol = 9/1 (weight ratio) in the case of cellulose triacetate, in acetone in the case of cellulose diacetate, at a concentration C (g / L; about 2.00 g / L). Dissolve by obtaining the exact value). This solution is poured into an Ostwald viscometer, and the time t (second) at which the solution passes between the marking lines of the viscometer is measured at 25 ° C. On the other hand, for the mixed solvent alone, the currency time t ₀ (second) is measured in the same manner as above,
The degree of polymerization is calculated according to the following formula.

Ηrel = t / t₀ [Η] = (ln η_rel) / C DP = [η] / K (Where t is the transit time of the solution (seconds), t₀Is the passage of solvent
Time (second), C is cellulose ester concentration (g / L),
η_relIs relative viscosity, [η] is intrinsic viscosity, DP is average polymerization
Indicates the degree. K is a constant, and in the case of cellulose triacetate
If K = 6 × 10 ^-Four, In the case of cellulose diacetate,
K = 9 × 10^-Four).

[Peelability] The peelability of the film by the casting method was evaluated as follows. Cellulose ester 100
By weight, 320 parts by weight of methylene chloride, 40 parts by weight of methanol, 25 parts by weight of butanol and 15 parts by weight of triphenyl phosphate (TTP) are mixed and dissolved to prepare a solution. This solution was cast at a temperature of 20 to 25 ° C. on a smooth stainless steel plate (support) to a thickness of about 1 mm,
The film is peeled off from the support when the solvent is appropriately left to stand at -25 ° C for 3 to 4 minutes, and the releasability is evaluated according to the following criteria.

◯: Peeling resistance is small, it can be peeled smoothly, and the film surface is smooth. X: Peeling resistance is large, it cannot be peeled smoothly.
Or, the peeled material from the film adheres to the stainless steel plate.

Comparative Example 1 Hardwood Kraft Method Dissolving Pulp (carboxyl group content 1.
2 meq / 100g) 50 parts by weight of acetic acid was sprayed on 100 parts by weight of the pretreatment to activate pretreatment, and then 470 parts by weight of acetic acid,
The mixture was acetylated by adding 265 parts by weight of acetic anhydride and 8.3 parts by weight of sulfuric acid. Then, water was added to partially hydrolyze the mixture, and cellulose triacetate (carboxyl group content 0.86 me) was obtained by adding magnesium acetate and calcium hydroxide as a reaction terminator and a heat resistance stabilizer.
q / 100 g (cellulose equivalent), mannose content of 0.
2 mol%, xylose content 1.0 mol%, acetylation degree 61.
0%, degree of polymerization 305) was obtained. As a result of evaluating the releasability of the obtained cellulose triacetate, the result was x.

Example 1 50 g of cellulose triacetate prepared in Comparative Example 1,
597 g of methylene chloride and 40 g of methanol were mixed and dissolved. Add 0.082 g of trifluoroacetic acid and stir,
After 30 minutes, 5 mL of a 2.0 M hexane solution of trimethylsilyldiazomethane was added dropwise, and the mixture was reacted at room temperature for 24 hours.
After 0.8 g of acetic acid was added to complete the reaction, 800 g of methanol was added to precipitate cellulose triacetate in which the carboxyl group was derivatized (methyl esterified), washed with water, and dried in vacuum. The obtained cellulose triacetate (carboxyl group content 0.1 meq / 10
As a result of evaluating the releasability of 0 g (converted to cellulose), mannose content 0.2 mol%, xylose content 1.0 mol%, the result was ◯. The peelability was greatly improved as compared with Comparative Example 1.

Comparative Example 2 Hardwood Kraft Method Dissolving Pulp (carboxyl go content 1.
2 meq / 100g) 50 parts by weight of acetic acid was sprayed on 100 parts by weight of the pretreatment to activate pretreatment, and then 470 parts by weight of acetic acid,
The mixture was acetylated by adding 265 parts by weight of acetic anhydride and 8.3 parts by weight of sulfuric acid. Then, water is added to partially hydrolyze the mixture, and cellulose acetate (carboxyl group content 0.84 meq is obtained by adding magnesium acetate and calcium hydroxide as a reaction terminator and a heat stabilizer.
/ 100 g (calculated as cellulose), mannose content 0.3
Mol%, xylose content 1.0 mol%, degree of acetylation 55.1
%, The degree of polymerization 160). A 30 wt% acetone solution was prepared from the obtained cellulose diacetate, and a spinning test was conducted. As a result, yarn breakage occasionally occurred.

Example 2 500 g of cellulose diacetate prepared in Comparative Example 2,
5970 g of methylene chloride and 400 g of methanol were mixed and dissolved. 0.82 g of trifluoroacetic acid was added and stirred, and after 30 minutes, 2.0 of trimethylsilyldiazomethane was added.
50 mL of M hexane solution was added dropwise and reacted at room temperature for 24 hours. After 8 g of acetic acid was added to complete the reaction, the mixture was added to 8000 g of methanol to precipitate the cellulose diacetate having a carboxyl group derivatized (methyl esterified), washed with water and dried. The obtained cellulose diacetate (carboxyl group content 0.1 meq / 100
g (cellulose equivalent), mannose content 0.3 mol%,
A 30 wt% acetone solution was prepared from a xylose content of 1.0 mol%) and a spinning test was conducted. As a result, yarn breakage was reduced as compared with Comparative Example 2.

Example 3 Cellulose triacetate was prepared in the same manner as in Comparative Example 1 except that a softwood sulfite method dissolving pulp (carboxyl go content 2.5 meq / 100 g) was used. Derivatization was performed using trimethylsilyldiazomethane in the same manner (carboxyl group content 0.1 meq / 100 g (calculated as cellulose), mannose content 0.9 mol%, xylose content 1.5 mol%).
The result of evaluating the peelability of this cellulose triacetate was ◯.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toru Shibata             290 at 2-1111 Jomidai, Himeji City, Hyogo Prefecture F-term (reference) 4C090 AA02 AA05 BA26 BB02 BB12                       BB14 BB36 BB52 BB65 BB97                       BC10 BD36 CA39 DA06 DA28                       DA32                 4L035 BB02 BB03 BB11 FF01 HH10

Claims (17)

[Claims] 1. A cellulose ester having a reduced carboxyl group content by sealing. 2. The cellulose ester according to claim 1, which has a carboxyl group content of 1 meq / 100 g or less in terms of cellulose. 3. The cellulose ester according to claim 1, which is substantially free of a carboxyl group. 4. The mannose content is 0.4 mol% or more, and the carboxyl group content is 1.1 in terms of cellulose.
The cellulose ester according to claim 1, which has a meq / 100 g or less. 5. The cellulose ester according to claim 1, which has a mannose content of more than 0.1 mol% and less than 0.4 mol% and a carboxyl group content of 0.8 meq / 100 g or less in terms of cellulose. 6. The mannose content is 0.1 mol% or less, and the carboxyl group content is 1.1 in terms of cellulose.
The cellulose ester according to claim 1, which has a meq / 100 g or less. 7. The cellulose ester according to claim 1, wherein the ratio (molar ratio) of the xylose content to the mannose content is less than 3, and the carboxyl group content is 1.1 meq / 100 g or less in terms of cellulose. 8. The cellulose ester according to claim 1, wherein the ratio (molar ratio) of the xylose content to the mannose content is 3 or more, and the carboxyl group content is 0.8 meq / 100 g or less in terms of cellulose. 9. The encapsulation reduces the carboxyl group content to 1 me.
The cellulose ester according to claim 1, which is prepared from cellulose having a q / 100 g or less. 10. The encapsulation reduces the carboxyl group content to 0.
The cellulose ester according to claim 1, which is prepared from cellulose having a weight of 7 meq / 100 g or less. 11. The cellulose ester according to claim 1, which is prepared from cellulose substantially free of a carboxyl group by sealing. 12. The encapsulation reduces the carboxyl group content to 1
Hardwood pulp reduced to less than meq / 100g, softwood pulp reduced in carboxyl group content to less than 1.5 meq / 100g, and carboxyl group content reduced to 1 meq
Cellulose ester according to claim 1, prepared from at least one cellulose selected from cotton linter pulp reduced to / 100 g or less. 13. A dope containing the cellulose ester according to claim 1. 14. A method for improving the releasability or spinnability of a film from a support, using the dope according to claim 13. 15. A molded body formed of the cellulose ester according to claim 1. 16. The molded product according to claim 15, which is a film or a fiber. 17. A method of acylating cellulose to produce a cellulose ester having a reduced carboxyl group content, which comprises sealing the carboxyl group of the cellulose or the cellulose ester produced by acylation to obtain a carboxyl group having a carboxyl group content. A method of producing reduced cellulose ester.