JP2001214357A - Formed article made from polysaccharides and method of producing the polysaccharide formed article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fibrous or filmy formed article made from polysaccharides having β-1,3-glucoside bonds, capable of being used for clothes and various materials, capable of being added to food for the purpose of improving a feeling when eaten and keeping shape of the food, and further suitable for medical applications, and to provide a method of producing the same. SOLUTION: This fibrous formed article is made from polysaccharides having β-1,3-glucoside bonds, wherein the formed article has a wet tensile strength lowering rate of <=50% which is specified in the following: 100×(Sd-Sw)/Sd(%) (Sd is a dry tensile strength; and Sw is a wet tensile strength).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention can be used for clothing and materials, and can be added to foods to improve texture and shape retention, and is also suitable for medical use. −
The present invention relates to a fibrous or film-shaped excipient comprising a polysaccharide having 1,3 glucoside bonds and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Fibers made from natural materials have been developed because they have excellent properties such as safety to human bodies and biodegradability. Among natural materials, polysaccharides exist in various types as macromolecules produced by living organisms, such as chitosan having antibacterial properties,
Some have functionality, and shaping into fibers has been attempted.

[0003] Under these circumstances, polysaccharides having β-1,3 glucosidic bonds gel when heated in an aqueous dispersion thereof.
It is biodegradable, harmless to the human body, and edible. Furthermore, among polysaccharides having β-1,3 glucoside bonds, those called curdlan have been confirmed to have an antitumor effect by immunostimulation.

By the way, polysaccharides having β-1,3 glucosidic bonds have hitherto been used mainly for foods by utilizing their high safety and excellent gelling ability. For example, it has been used as a substitute for gelatin for processing into jellies or for adding to noodles to improve elasticity.

Further, a method of processing into a fibrous form has also been proposed. For example, Japanese Patent Publication No. 48-16618 discloses a β-
It has been shown that by adding an undiluted spinning solution obtained by dissolving a polysaccharide having a 1,3 glucoside bond in an aqueous alkaline solution to an kneaded product as a fibrous material with an acidic coagulation liquid, a good-quality natural meat texture can be obtained. .

Japanese Unexamined Patent Publication (Kokai) No. 3-157401 discloses that a curdlan water suspension is passed through a thin tube and heated by utilizing the heat-coagulability of curdlan, thereby forming a konjac-like product for edible use. A method for producing a linear gel body is shown. Japanese Patent Application Laid-Open No. 7-135911 discloses a molded food having a chewy and uneven texture, in which a fibrous gel of a polysaccharide having β-1,3 glucoside bonds is added to the food.

As described above, the β-
The fibrous material of a polysaccharide having 1,3 glucoside bonds is in a gel form, and is limited to food use as an additive for the purpose of improving texture, and is not used alone as a fiber. This is because β-1, 3 obtained by the conventional method
Fibers composed of polysaccharides having glucosidic bonds have low tensile strength when wet. That is, the conventional β-
Fibers composed of polysaccharides having 1,3 glucosidic bonds
It is obtained by heating and coagulating the polysaccharide dispersed in water, or obtained by dissolving the polysaccharide in an aqueous alkali solution by acid coagulation. However, when immersed in water, the fiber easily swells, causing a problem that the strength is sharply reduced. Therefore, it could not be used in applications other than foods that require strength even when wet.

For example, when the fibers are used for clothing, when the clothes are moistened by sweating or washing, the fibers swell and the strength is reduced, the form easily collapses, and in some cases, the fabric breaks. Would. Dyeing with heating also reduces the strength of the fiber, making it difficult to carry out a dyeing treatment.
Alternatively, when a polysaccharide sheet or nonwoven fabric is produced by a wet method, the excipient needs to have wet strength, but a fiber or a fiber comprising a polysaccharide having a β-1,3 glucoside bond obtained by a conventional method or The film-shaped shaped article did not have the strength necessary to withstand processing.

[0009] A sheet of polysaccharide by a method other than the wet method,
Alternatively, even if a non-woven fabric can be produced, if the obtained product is placed in a humid atmosphere, the strength is reduced, and germs are more likely to occur, making it difficult to use continuously and for a long time. In addition, when used in food applications, food packaging applications, and medical applications, sterilization treatment is required.However, fibers obtained by the conventional shaping method are heated in a wet heat state because the fibers lose their strength when wet. The sterilization process could not be performed. Also, β-
When a spinning solution obtained by dissolving a polysaccharide having a 1,3 glucoside bond in an aqueous alkaline solution is discharged into an acidic coagulation liquid and shaped into a thread, the swollen coagulation yarn has low strength and increases the strength of the obtained fiber. Therefore, it was difficult to perform a drawing process of the coagulated yarn.

In order to improve this point, Japanese Patent Publication No. Sho 62-2
No. 9527 proposes to use sulfuric acid or a mixed solution of hydrochloric acid and alcohol as a coagulation bath to avoid swelling of coagulated yarn. Although the coagulated yarn formed into fibers by this method has improved strength, the obtained dried yarn still swells in water, and its wet strength is low.
In addition, when these fibers are used in food applications, sufficient neutralization and washing are required, but if these treatments are not performed in water, it is not possible to efficiently remove the alkali or acid in the fibers. Have difficulty.

Further, it is convenient to handle the fibers as tows, which are usually fiber bundles. However, fibers which swell in water may cause inter-fiber adhesion during drying when the wet fiber bundle tow is dried. Become. In order to avoid this fiber-to-fiber adhesion, there is a method of applying an oil agent to wet fibers. However, oil agents should be applied to fibers used for food applications. Japanese Patent Application Laid-Open No. 7-310238 describes a method for suppressing the generation of mold on the resulting fiber by using a non-acidic aqueous solution containing an alkaline earth metal salt or an alkali metal salt as a main component as a coagulating liquid. However, since the obtained fibers swell in water, the generation of mold cannot be fundamentally suppressed.

[0012]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to solve the above-mentioned problems. As a result, they have a small decrease in strength even when wet, and can be used in applications other than food, such as β-1,3 glucoside. A fiber comprising a polysaccharide having a bond, and β-
The present inventors have found a method for producing a polysaccharide excipient, in which a stock solution obtained by dissolving a polysaccharide having 1,3 glucoside bonds in formic acid having a concentration of 90% or more is formed by a wet coagulation method.

That is, the present invention relates to a fiber comprising a polysaccharide having β-1,3 glucosidic bonds, wherein the tensile strengths when dry and wet are Sd and Sw, respectively, defined by the following formula: Fiber strength drop when wet

(Equation 2) Is not more than 50%, and β-
A fiber comprising a polysaccharide having 1,3 glucosidic bonds, having a dry tensile strength of 1 g / dtex or more;
Wet strength reduction rate specified in the following formula

(Equation 3) To 50% or less, and to a method for producing these fibers. Here, the strength Sd during drying is a temperature of 20 ° C.
The tensile strength of the fiber in an equilibrium state at a humidity of 50%, and the wet strength Sw is the tensile strength of the fiber when immersed in water at 20 ° C. for 30 minutes or more.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in more detail.

The polysaccharide fiber of the present invention is a fiber obtained by a method in which a polysaccharide having a β-1,3 glucoside bond is dissolved in formic acid and spun, and swells even in water or even in boiling water. It is a fiber having a low wettability and a small difference in strength between dry and wet strengths. Further, in the conventional method, it is difficult to draw the wet fiber because of its low strength, whereas in the method for producing the fiber of the present invention, the fiber can be easily drawn, and the molecular orientation of the obtained fiber is increased. It is also possible to improve the strength. Further, in the fiber production method of the present invention, since the coagulated yarn does not swell or has a small swelling ratio, inter-fiber adhesion hardly occurs during drying, and therefore, it is not necessary to apply an oil agent to avoid inter-fiber adhesion. .

The fiber of the present invention can be sterilized by heating with hot water or steam. Furthermore, since the fiber of the present invention hardly swells even in a state of being in contact with water as well as in a dry state, it is difficult for mold to propagate.

The fiber of the present invention is preferably produced by dissolving a polysaccharide having β-1,3 glucosidic bonds in formic acid and spinning. As a solvent for dissolving a polysaccharide having a β-1,3 glucoside bond, an alkaline aqueous solution, a urea aqueous solution,
Although dimethyl sulfoxide and the like are also used, fibers made by using these solvents tend to be easily swellable in water as compared with the fibers of the present invention.

The reason why the fiber of the present invention is unlikely to swell even in a humid atmosphere is not clear at present, but the β-
It is presumed that polysaccharides having 1,3 glucosidic bonds are dissolved in high concentration of formic acid and spun to increase the orientation of the fiber and make the interior of the fiber hydrophobic.

The polysaccharide having β-1,3 glucosidic bonds as referred to in the present invention is a water-insoluble polysaccharide mainly composed of β-1,3 glucosidic bonds. Paramylon, laminaran, pakiman and the like. However, the present invention is not limited to these, and it may be any as long as it is mainly composed of β-1,3 glucoside bonds and is water-insoluble. Further, the terminal group may have a group other than D-glucose, or another branched sugar chain may be present. Alternatively, a linear β-1,3 glucan may be obtained by removing a part or all of the branched sugar chains by a decomposition treatment.

In the method for producing the fiber of the present invention, β-
A solution obtained by dissolving polysaccharides having 1,3 glucoside bonds in formic acid is used as a spinning dope. The concentration of the polysaccharide having β-1,3 glucoside bonds in the spinning dope is 1% by mass or more and 30% by mass or less. Is preferred. When a stock solution containing less than 1% by mass of a polysaccharide having β-1,3 glucoside bonds is used, it is difficult to obtain a strong coagulated yarn and spinning of a continuous yarn becomes difficult. On the other hand, when a spinning dope having a polysaccharide concentration of more than 30% by mass is used, the viscosity becomes high, so that it is difficult to dissolve the polysaccharide in a solvent under stirring, defoam, and filter.

In the present invention, when preparing a stock solution for shaping, the purity of formic acid that dissolves polysaccharides having β-1,3 glucoside bonds is preferably 90% or more. It is possible to dissolve polysaccharides having β-1,3 glucosidic bonds in a formic acid aqueous solution having a concentration of less than 90%, but the coagulation speed of the coagulated yarn obtained by discharging the thus obtained spinning stock solution into the coagulation solution is reduced. At the same time, there is a tendency that the strength of the coagulated yarn decreases and drawing becomes difficult. In addition, in the case of a spinning dope prepared with a formic acid aqueous solution having a formic acid concentration of about 80%, the coagulated yarn is swollen and the obtained dried yarn swells in water, which is not preferable.

When a spinning solution is prepared by dissolving a polysaccharide in formic acid, depending on the type of polysaccharide having β-1,3 glucoside bonds, its decomposition occurs with time even at a temperature lower than room temperature. The degree of polymerization may decrease. As a result,
The viscosity of the spinning dope decreases, the spinnability decreases, and the strength of the obtained fiber decreases. In order to prevent such inconvenience, the spinning solution is preferably used as soon as possible after preparation, and is preferably used within one week after preparation of the stock solution. In addition, the strength of the fiber has a correlation with the draw ratio during spinning,
The higher the draw ratio, the higher the strength. Therefore, by changing the draw ratio, the fiber strength can be appropriately changed according to the application.

The fiber strength depends on the concentration of the stock solution and the conditions of coagulation, but in order to obtain a fiber having a strength of 1 g / dtex or more, it is preferable to draw the coagulated yarn twice or more. In the present invention, there is no problem even if the coagulated yarn is subjected to a drawing treatment of less than twice or spun without the drawing treatment, for example, when it is desired to obtain a low-strength fiber. No fibers can be obtained. In the case of drawing, it is necessary to draw wet fibers. Even if completely dried fiber is drawn, the drawing cannot be performed effectively, and the fiber is easily broken at the time of drawing.

The stretching treatment can be carried out in air at room temperature or in water at room temperature or lower. In this case, if the stretching tension is relaxed, the fibers are slightly contracted elastically. It is preferred to draw the fibers at 50 ° C. or higher, preferably at 70 ° C. or higher. In this case, the stretching is preferably performed using hot water or steam. If the fiber is in a wet state at the time of drawing, the heating can be performed using a warm air, a dry heat roll, a non-contact heater, or the like.

The shaping stock solution is shaped by a wet shaping method or a dry-wetting shaping method to obtain a shaped product. The case of the wet shaping method will be described in detail below. First, a spinning stock solution is discharged from a spinneret immersed in a coagulation bath into a coagulation bath and taken out to obtain a coagulated yarn. The spinneret can be used from one to a plurality of holes, and the hole shape is not limited to a round shape, but various shapes can be used. The coagulating liquid is one that rapidly lowers the strength of the fiber obtained by dissolving the fiber formed during coagulation. For example, the coagulating ability of the spinning stock solution is not limited to a formic acid aqueous solution having a concentration of 50% or more or an alkaline aqueous solution having a pH of 13 or more. There is no particular limitation as long as there is. Therefore, for example, water, an alkaline aqueous solution, an acidic aqueous solution, an alcohol, or a mixed solution thereof can be used.

When alcohol is used alone or as a mixture as a coagulating liquid, and when the obtained fiber is used for food, ethanol is preferably used.
Although the coagulation liquid can coagulate the fibers even at room temperature, it can be set freely for the purpose of controlling the coagulation speed.
Thereafter, the coagulated yarn is subjected to neutralization, washing, and stretching. In the stretching process, when high-strength fibers are required, it is preferable to perform stretching at a high magnification as far as possible without breaking.

A neutralization treatment may be performed so that the fibers become neutral before and after washing. Stretching may be performed before or after washing and neutralization. After the neutralization treatment, washing may be performed. The stretching is performed in the air, in water, or in steam. In order to uniformly stretch the fiber without difficulty, the temperature is preferably 50 ° C. or higher, and more preferably 70 ° C. or higher. In this case, it is preferable to perform the drawing in warm water or steam. Alternatively, the fibers in a wet state can be dried while being stretched using warm air or a dry heat roll or a non-contact heater.

For the purpose of simultaneously performing coagulation and drawing, a method of discharging a spinning stock solution into a coagulation bath and drawing the coagulation yarn at a high draft ratio, or by drawing a coagulation yarn through a rotating roll in the coagulation bath. And a method of stretching in a coagulation bath. In this method, washing is performed next, but a neutralization treatment may be performed before or after washing. The stretching treatment may be performed in one stage, or may be performed in multiple stages. When dividing into multiple stages, there is no problem even if different stretching methods are combined. The drawn fiber may be cut to a predetermined length as it is, or after drying, or after drying. The cut undried fibers can be dried to produce a product. This is, for example, the case where the cut undried fiber is placed on a net and dried with hot air.
The fibers of the present invention do not adhere to each other when dried by such a method.

Further, for the purpose of suppressing the shrinkage of the fiber during wetting or heating and adjusting the elongation, the wet fiber or the dry fiber is relaxed in boiling water or saturated steam before or after cutting. The fiber after the relaxation treatment can be undried or dried to obtain a product. The fiber of the present invention can be cut into a product as described above, or can be cut into a filament without cutting. The cut fibers can be spun alone or mixed with other fibers, or can be cut alone or mixed with other fibers to be processed into a sheet or nonwoven fabric. Since the fiber of the present invention does not swell even in water or boiling water, it can be processed not only by a dry method but also by a wet method as a method of processing into a sheet or a nonwoven fabric.

It is also possible to use the cut fiber as it is, or to refine it by beating or pulverizing, and add it to food. The fibers may be used alone or mixed with fibers of other materials for use in clothing, or may be used alone or mixed with fibers of other materials to form a sheet or nonwoven fabric. In this case, for medical use, it can be used in the form of a fiber bundle, a sheet, or a non-woven fabric for the purpose of utilizing antitumor properties. Further, since it has high compatibility with a living body and has a small decrease in strength when wet, it can be used as a suture. Further, it can be used for material use such as food packaging. In addition, since the strength is less reduced by hot water or steam, sterilization is easy,
It is a fiber suitable for food, food packaging and medical use.

As described above, the fiber of the present invention can be widely used not only for clothing and materials, but also for food, food packaging, and medical use.

[0032]

The present invention will be described in more detail with reference to the following examples.

The tensile strength of the fibers obtained in the following Examples and Comparative Examples was measured under the following conditions. (Drying strength) Drying strength (Sd) was measured at a temperature of
After equilibration in the condition of 50% humidity all day and night, 10
It is the average value of the tensile strength of the single fibers measured by Tensilon. (Wet strength) Wet strength (Sw) is an average value of tensile strength of ten single fibers measured by tensilon after immersing fibers in water at a water temperature of 20 ° C for 30 minutes. (Strength decrease rate) The strength decrease rate when wet was determined by the following equation.

(Equation 4)

Example 1 Curdlan (manufactured by Wako Pure Chemical) was dissolved in 98% pure formic acid (manufactured by Wako Pure Chemical) with stirring at room temperature.
A spinning solution having a solid content of 10% by mass was obtained. For defoaming,
Left at room temperature overnight. The obtained spinning stock solution is discharged from a spinneret having a pore size of 0.15 mm and 50 holes into a coagulation bath of deionized water at 25 ° C., and then washed with deionized water at 80 ° C., followed by 1% sodium bicarbonate. The aqueous solution was dropped 80
After passing through a neutralization bath at 80 ° C., the film was stretched 1.5 times in warm water at 80 ° C., and dried with a dry heat roller at 80 ° C. The dried fibers were easily separated. Table 1 shows the fineness of the obtained fibers, and the strength when dry and when wet. The fibers did not swell even when wet, and there was almost no change in appearance. In addition, no mold was found when left at room temperature for one month in a wet state.

Example 2 A curdlan fiber was obtained under the same conditions as in Example 1 except that the draw ratio was 3.0. Table 1 shows the fineness of the obtained fibers, and the strength when dry and when wet. The fibers did not swell even when wet, and there was almost no change in appearance. In addition, no mold was found when left at room temperature for one month in a wet state.

Comparative Example 1 Curdlan was dissolved in an aqueous 0.1 N sodium hydroxide solution with stirring to obtain a spinning dope having a solid content of 10% by mass. It was left at room temperature overnight for defoaming. An aqueous solution in which acetic acid is dissolved in saturated NaCl and the acetic acid concentration is 5% is used as a coagulating liquid, and the spinning stock solution is discharged from a spinneret having a pore size of 0.15 mm and 50 holes in a coagulating bath at 25 ° C, and heated to 80 ° C with hot water. After washing with, an ethanol bath was passed through in order to suppress adhesion during drying, the film was stretched 1.5 times therein, and then dried with a drying roller at 80 ° C. It should be noted that stretching three times was impossible. Table 1 shows the fineness of the obtained fibers, and the strength when dry and when wet. Upon wetting, the fibers swelled and an increase in diameter was observed.

[0037]

[Table 1]

[0038]

According to the present invention, it is possible to obtain a fiber having a small decrease in strength even when wet from a polysaccharide having β-1,3 glucosidic bonds as a raw material. It is possible.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4B035 LE01 LE05 LG20 LK19 LP33 4L035 AA06 BB06 BB12 BB15 BB72 BB89 BB90 BB91 EE08 EE11 FF01 4L047 AA08 AB02 AB03 AB10 CB10 CC01 CC03 CC14 CC16

Claims (8)

[Claims] 1. A fibrous excipient comprising a polysaccharide having β-1,3 glucoside bonds, wherein the tensile strengths when dry and wet are Sd and Sw, respectively, defined by the following formula: Tensile strength decrease rate when wet Is 50% or less, a fibrous excipient comprising a polysaccharide. 2. A fibrous excipient comprising a polysaccharide having β-1,3 glucoside bonds, wherein the tensile strength when dried is 1 g / dtex or more. A fibrous excipient composed of polysaccharides. 3. A method for producing a polysaccharide excipient, which comprises subjecting a stock solution obtained by dissolving a polysaccharide having β-1,3 glucoside bonds to formic acid to a wet excipient to obtain a polysaccharide excipient. 4. A polysaccharide excipient having a β-1,3 glucoside bond is a fibrous excipient, and the fibrous excipient has the characteristics defined in claim 1 or 2. The method for producing a polysaccharide excipient according to claim 3, wherein: 5. The stock solution according to claim 3, wherein the stock solution has a concentration of the polysaccharide having a β-1,3 glucoside bond contained in the stock solution of 1% by mass or more and 30% by mass or less. A method for producing an excipient comprising a polysaccharide. 6. The method for producing a polysaccharide excipient according to claim 3, wherein formic acid having a purity of 90% by mass or more is used. 7. The method for producing a fiber comprising a polysaccharide having β-1,3 glucoside bonds, wherein the fiber in a wet state is drawn at least two times. Manufacturing method. 8. A method for producing a fiber comprising a polysaccharide having β-1,3 glucosidic bonds, wherein the wet fiber is stretched at 50 ° C. or higher.
A method for producing a fiber comprising the polysaccharide according to the above.