JPH09291414A - Biodegradable cellulose acetate-based fiber and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a biodegradable cellulose acetate-based fiber obtained by melt spinning a biodegradable cellulose acetate composition consisting essentially of cellulose acetate, a biodegradable polymer and a plasticizer and provide a method for producing the biodegradable cellulose acetate-base fiber. SOLUTION: This biodegradable cellulose acetate-based fiber is obtained by melt spinning a biodegradable resin composition consisting essentially of cellulose acetate, a biodegradable polymer and a plasticizer at 190-230 deg.C spinning temperature and 200-600 spinning draft. The biodegradable resin composition contains the cellulose acetate having 30-56% acetyl content and 150-250 average polymerization degree in an amount of 45-65wt.% based on the total bone dry weight, the biodegradable polymer in an amount of 5-25wt.% based on the total bone dray weight and a biodegradable polyester-polyol having 400-2,000 average molecular weight or a mixture thereof with a biodegradable polyether- polyol having 400-1,000 average molecular weight in an amount of 25-40wt.% based on the total bone dry weight. An aliphatic polyester is contained as the biodegradable polymer in the biodegradable resin composition.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a biodegradable cellulose acetate fiber obtained by melt-spinning a biodegradable cellulose acetate composition containing cellulose acetate, a biodegradable polymer and a plasticizer as main components, and a fiber thereof. It relates to a manufacturing method.

[0002]

2. Description of the Related Art In recent years, as the recognition for environmental protection has deepened, the problem of processing plastic waste has been emphasized, and for disposable applications such as non-woven fabrics produced by melt spinning from synthetic resin as a raw material. , There is a growing desire to use biodegradable resins that can be composted as raw materials. Under these circumstances, various biodegradable polyester resins have been developed for use in melt spinning, but they have not come into widespread use because of their high price. On the other hand, polysaccharides derived from natural products are expected to be biodegradable, safe, inexpensive, and have a stable supply of raw materials. The thing is unknown.

Cellulose acetate, which is widely used as a general-purpose resin from cellulose as a raw material in the polysaccharide system, is produced by completely acetylating cellulose and then partially saponifying it. It has become known that those below 100% are inherently biodegradable. However, since the cellulose acetate has a melting point and a thermal decomposition temperature that are close to each other, it is difficult to perform thermoforming, and is usually used as a composition to which a plasticizer is added. For the above reason, cellulose acetate is also widely used as an acetate fiber because of the above reason, the fiber is produced by a dry spinning method which is generally performed by dissolving it in a solvent. As a special example without using the dry spinning method, a water-soluble plasticizer such as polyethylene glycol is blended and melt-spun,
It is known to produce fibers for hollow fibers, but even if polyethylene glycol having an average molecular weight of 200 to 1000 disclosed in Japanese Patent Publication No. 53-11564 is used alone, the breaking rate at the time of spinning From the point of, the spinning draft is 2
When it is 00 or more, it is difficult to increase the spinning speed and perform melt spinning. In addition, the use of a highly hygroscopic plasticizer such as polyethylene glycol alone is very limited in terms of application.

On the other hand, phthalate ester type plasticizers used for extrusion and injection molding having high plasticity or plasticizers such as triacetin and triethyl citrate which are known to be biodegradable are not extruded and injection molded. When it is applied to melt spinning with a high thermoforming temperature, it has many volatile components, and unless it has a considerably low spinning draft, melt spinnability is not exhibited and productivity is poor. On the other hand, in order to solve these drawbacks of cellulose acetate and enable melt spinning which does not require solvent recovery equipment and can be sped up, cellulose acetate propionate can be acetylated and simultaneously propionylated or butyrylized. Alternatively, there has been an attempt to impart melt spinnability to some extent by using cellulose acetate butyrate and lowering the melting point, but in this case, the hydrophobicity of the fiber becomes strong and the biodegradability decreases or disappears. Therefore, the production of biodegradable fibers by the melt spinning method using a cellulosic resin has not been realized yet.

[0005]

In view of the above situation, the present inventors have aimed to obtain a biodegradable cellulose fiber by a melt spinning method, and have a degree of acetylation of 56% or less and a degree of polymerization of 150 or more. Biodegradable polyester polyol with a specific amount of cellulose acetate having specificity, a hydroxyl group at the end in the range of a specific average molecular weight as a plasticizer, and little or no vapor pressure near the spinning temperature. Or a mixture of the polyester polyol and a biodegradable polyether polyol having an average molecular weight in the range of 400 to 1000 in a specific ratio to lower the spinning temperature, and to prepare a composition during melt spinning by blending a plasticizer. By compensating for the decrease in strength so as to increase the average degree of polymerization of the cellulose acetate, the spinning temperature is from 190 to 230 ° C. and the spinning draft is 20. Ability to express melt spinnability of the cellulose acetate composition is excellent in the above, and the resulting cellulose acetate fibers were found to have superior thread strength and biodegradability.

However, in this case, from the viewpoint of productivity during melt spinning, in order to further improve productivity, it is required to reduce the yarn breakage rate during spinning, and for that purpose, the spinning temperature is kept low. Therefore, it is required to suppress the volatilization of the plasticizer and the thermal decomposition of the cellulose acetate and the plasticizer, and to further increase the strength of the composition during melt spinning. But,
With a combination of cellulose acetate and plasticizer only,
If the plasticizer content is increased, the spinning temperature will decrease, but the strength of the composition during melt spinning will decrease and the yarn breakage rate during spinning will increase.On the other hand, if the plasticizer content is reduced, the melting Although the strength of the composition during spinning is improved, the plasticizing effect is small, the spinning temperature is high, the volatilization amount of the plasticizer is increased, and the thermal stability of the cellulosic acetate and the plasticizer is lowered, and the breaking during spinning is decreased. The yarn ratio increases, and as a result, it is difficult to improve the strength of the composition while keeping the spinning temperature low.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above-mentioned problems, and as a result, a combination consisting only of cellulose acetate and a plasticizer has essentially biodegradability and cellulose. Attention was paid to the fact that a polymer having a melting point lower than that of acetate was partially replaced and used in the combination of the cellulose acetate and the plasticizer, and the compatibility was first investigated. As a result, even if a biodegradable polymer that is incompatible with cellulose acetate or is difficult to compatibilize, if it is used in a specific amount in the presence of the plasticizer in a specific range, it may be very easily compatible by kneading. I found that there is. It is considered that this phenomenon is because the plasticizer acts as a compatibilizing agent to improve the kneadability and compatibility of the cellulose acetate and the biodegradable polymer. Further, as a result of variously adding a compatible biodegradable polymer to the combination consisting of the cellulose acetate and a plasticizer only, for the purpose of improving the strength of the composition during spinning while suppressing an increase in spinning temperature. It has been found that the strength is improved while the spinning temperature is kept low in the compounding ratio of the three components within the specific range. This is because by introducing by adding a biodegradable polymer having a low melting point, even if the compounding amount of the plasticizer was reduced, the increase in spinning temperature was suppressed, and cellulose acetate as a high molecular weight component It is considered that this was because the compounding amount of the degradable polymer could be increased.

As a result of the above examination, it was found that biodegradable polymers having good compatibility, low melting point and high strength are generally effective. Aliphatic polyesters such as polycaprolactone and polyethylene adipate were suitable. In addition, even a cellulose derivative having a melting point slightly higher than that of an aliphatic polyester such as cellulose propionate could be sufficiently effective depending on the blending amount. In this way, it becomes possible to substitute a specific amount of the biodegradable polymer for the plasticizer in the combination of the cellulose acetate and the plasticizer, and as a result, the composition during spinning is suppressed while suppressing an increase in spinning temperature. Spinning temperature of 190-23
Biodegradable cellulose acetate fibers can be efficiently produced at 0 ° C. and a spinning draft of 200 or more, and the present invention has been completed. The object of the present invention is to melt spin a biodegradable cellulose acetate composition comprising cellulose acetate, a biodegradable polymer, and a polyester polyol as a plasticizer, or a mixture of said polyester polyol and polyether polyol. The invention provides a biodegradable cellulose acetate fiber and a method for producing the same, which solves the above-mentioned problems that occur when a fiber is produced by melt-spinning a composition consisting of a combination of the cellulose acetate and a plasticizer, and which is significantly improved. To do.

A first aspect of the present invention is cellulose acetate,
In a biodegradable cellulose acetate fiber obtained by melt spinning a biodegradable resin composition containing a biodegradable polymer and a plasticizer as main components, the biodegradable resin composition has an acetylation degree of 30.
.About.56%, cellulose acetate having an average degree of polymerization of 150 to 250 is 45 to 65% by weight based on the total dry weight, biodegradable polymer is 5 to 25% by weight based on the total dry weight, and the average molecular weight is 400 to 2000. A biodegradable polyester polyol, or a plasticizer made of a mixture of the polyester polyol and a biodegradable polyether polyol having an average molecular weight of 400 to 1000, is added in an amount of 25 to 40 per total dry weight.
It is a biodegradable cellulose acetate fiber characterized in that it is contained by weight%. A second aspect of the present invention is the biodegradable cellulose acetate fiber according to claim 1, wherein the biodegradable polymer constituting the biodegradable resin composition is an aliphatic polyester. A third aspect of the present invention comprises spinning the biodegradable resin composition according to the first or second aspect of the present invention at a spinning temperature of 1
A method for producing a biodegradable cellulose acetate fiber, which comprises melt spinning at 90 to 230 ° C. and spinning draft 200 to 600.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The biodegradable resin composition used in the present invention has a spinning draft of 200 or more, which is represented by the ratio of the spinning speed to the spinneret hole discharge speed (spinning speed / spinneret hole discharge speed). The composition is for melt-spinning to produce a biodegradable cellulose acetate fiber, and this composition is mainly composed of cellulose acetate, a biodegradable polymer and a plasticizer. Cellulose acetate used in the present invention, after pretreating the cellulose pulp or linter such as softwood bleached kraft pulp or dissolving pulp with acetic acid, acetylated with acetic anhydride in the presence of an acidic catalyst such as sulfuric acid, then It is obtained by a known method of performing neutralization and aging, and is confirmed to have essentially biodegradability with an acetylation degree of 56% or less. When the degree of acetylation of cellulose acetate is less than 51%, it becomes easily degradable and biodegradable further, but a compound such as a biodegradable polyester polyol having an average molecular weight of 400 to 2000 is used as a plasticizer. As long as it is, biodegradation can be easily performed even if cellulose acetate having an acetylation degree of 51 to 56% is used.

However, cellulose acetate having an acetylation degree of less than 30% has poor water resistance and is not suitable for practical use. Therefore, the acetylation degree in the present invention is used in the range of 30 to 56%. Further, two or more kinds of cellulose acetates having different acetylation degrees may be mixed and used. To measure the degree of acetylation,
Sodium hydroxide (NaOH) according to the known neutralization titration method
It is calculated from the consumption of and is expressed as an average value. The average degree of polymerization of cellulose acetate is high to the extent that kneading with the plasticizer and subsequent melt spinning is possible in order to compensate for the strength during melt spinning of the cellulose acetate composition from the reduction caused by the incorporation of the plasticizer. Although it is moderately preferable, if it is 150 or more, a desired melt spinning property can be obtained. However, when the average degree of polymerization exceeds 250, the kneading property is lowered and it is not suitable. Therefore, in the present invention, cellulose acetate having an average degree of polymerization of 150 to 250 is used.

The average degree of polymerization (DP) is measured according to a known method by dissolving cellulose acetate in an acetone solvent and using the intrinsic viscosity [η] obtained from the relative viscosity obtained by using an Ostwald viscometer (1). ) Is obtained from the equation. [Η] = 0.09 × DP (1) The blending amount of cellulose acetate is 45 to 45 per 100% by total dry weight of cellulose acetate, biodegradable polymer and plasticizer.
It is in the range of 65% by weight. If the blending amount is less than 45% by weight, the strength of the composition during melt spinning decreases, and if the blending amount exceeds 65% by weight, the spinning temperature becomes too high and the volatilization amount of the plasticizer increases. Furthermore, the thermal stability of the cellulose acetate, the biodegradable polymer and the plasticizer decreases, and the yarn breakage rate increases during melt spinning, which is not suitable.

The biodegradable polymer that can be used in the present invention is known to have an essential biodegradability, has a melting point lower than that of cellulose acetate, and is compatible with the compounding combination of cellulose acetate and a plasticizer. Possible polycaprolactone, polyhydroxybutyrate,
Aliphatic polyesters such as polyethylene adipate, cellulose biopropionate having a specific degree of substitution with inherent biodegradation, cellulose acetate propionate, cellulose butyrate, hydroxyethyl cellulose, hydroxypropyl cellulose, and other cellulose derivatives, and vinyl acetate, vinyl alcohol. Etc.,
One or more selected from these are used. However, in order to improve the strength of the resin composition during melt spinning while suppressing an increase in spinning temperature by adding cellulose acetate and a plasticizer, the melting point of the biodegradable polymer is preferably low and the strength is high. .

Regarding the melting point of the biodegradable polymer, since the melting point of cellulose acetate is 230 ° C. or higher,
If the temperature is 200 ° C. or lower, a sufficient effect can be obtained. Further, the average molecular weight that affects the strength of the polymer is 1
When the average molecular weight is less than 10,000, the strength becomes weak, and when it exceeds 100,000, the compatibility with cellulose acetate decreases and the spinning temperature increases, which is not suitable.
An aliphatic polyester having a melting point of about 60 ° C., such as polycaprolactone, is particularly preferable for satisfying these conditions. The amount of the polymer compounded is 5 to 5% by total dry weight of cellulose acetate, biodegradable polymer and plasticizer.
It is in the range of 25% by weight. If the blending amount is less than 5% by weight, the effect of improving the strength is small, and if it exceeds 25% by weight, the compatibility decreases, which is not suitable.

As the plasticizer used in the present invention, a biodegradable polyester polyol having an average molecular weight of 400 to 2000 and having a hydroxyl group at the terminal and having little or no vapor pressure near the spinning temperature, or A mixture of the polyester polyol and a biodegradable polyether polyol having an average molecular weight in the range of 400 to 1000 can be mentioned. The blending amount of the plasticizer is 25 to 40% by weight based on the total dry weight of cellulose acetate, the biodegradable polymer and the plasticizer. If the blending amount exceeds 40% by weight, the strength of the resin composition during melt spinning will decrease, and if the blending amount is less than 25% by weight, the spinning temperature will be too high and the volatilization amount of the plasticizer will increase, and moreover cellulose Since the thermal stability of the acetate, the biodegradable polymer and the plasticizer is lowered and the yarn breakage rate during melt spinning is increased, the melt spinnability is lowered.

The polyester polyol used as a plasticizer is not particularly limited as long as it has biodegradability and good compatibility with cellulose acetate, but polycaprolactone diol having an average molecular weight of 400 to 2000, Examples thereof include polycaprolactone triol, polyethylene adipate, and the like, which can be selected from these and used alone or as a mixture of two or more kinds. When the average molecular weight of the polyester polyol is less than 400, the plasticizing effect is good, but near the spinning temperature, the low molecular weight component in the polyester polyol is volatile, and the thermal stability is low, and the fibers during spinning have bubbles. It is not suitable because it tends to occur and the strength of the composition during melt spinning is greatly reduced. On the other hand, when the average molecular weight exceeds 2000, the plasticizing effect is small, the kneading property is lowered, and the temperature at which melt spinning is possible becomes too high. Therefore, the heat stability of cellulose acetate, biodegradable polymer and plasticizer is increased. It is not suitable because it reduces the sex.

A polyether such as polyethylene glycol having a molecular weight in the range of 400 to 1000, which is biodegradable and has good compatibility with cellulose acetate, for the purpose of adjusting the melt viscosity, the physical properties and the like in combination with the polyester polyol. The polyol can be used within a range that does not impair the melt spinnability. In this case, the acceptable weight ratio of polyester polyol to polyether polyol is less than 1: 1. If this ratio exceeds 1: 1 and the amount of polyether polyol increases, the water resistance decreases, which is not suitable. In the present invention, a weak organic acid, an epoxy compound, a phosphate, a thiophosphate, etc., as a stabilizer for preventing thermal deterioration and thermal discoloration within a range that does not impair the performance required as needed, from among these, You may select and may add it individually or in mixture of 2 or more types. or,
Other organic acid-based biodegradation accelerators, lubricants, antistatic agents,
There is no problem in blending additives such as dyes, pigments and lubricants.

In the present invention, the biodegradability can be evaluated by burying it in soil or by measuring the weight loss according to JIS K 6950, but this test is easily degradable. Since it is a test method, in order to investigate the essential biodegradability, soil, activated sludge, etc. containing ASTM-D-5338 or cellulose acetate, a biodegradable polymer and a microorganism acclimatized to a compound used as a plasticizer, etc. A controlled environment can also be used. For mixing the cellulose acetate, the biodegradable polymer, the plasticizer and other additives used in the present invention, a known mixing device such as a kneader, a roll mill or a Banbury mixer can be used without particular limitation. In order to facilitate mixing, it is preferable that the particles of cellulose acetate be finely pulverized to 50 mesh or less beforehand by a pulverizer. The mixture thus obtained is preferably pelletized using an extruder before being fed to the melt spinning machine in order to reduce inclusion of air bubbles and the like. In addition, the pelletized biodegradable resin composition is preferably dried to a water content of 0.1% or less prior to melt spinning in order to prevent hydrolysis during melting and generation of bubbles.

In the melt spinning method used in the present invention, the above-mentioned biodegradable resin composition is heated and melted in a known extrusion spinning machine, and then extruded from a spinneret at a spinning temperature of 190 to 230 ° C. and spun. A continuous long fiber filament group is drawn by an ejector with high-speed air, opened, and wound as it is, or after being opened, it is deposited and collected on the surface of a support for collection to form a web. The spinning temperature at the time of melt spinning used means the temperature inside the spinneret for spinning. When the spinning temperature exceeds 230 ° C, the volatilization amount of the plasticizer increases, and moreover, cellulose acetate,
It is not suitable because the thermal stability of the biodegradable polymer and the plasticizer is lowered and the thermal decomposition or hydrolysis becomes remarkable. On the other hand, when the spinning temperature is lower than 190 ° C., the melt viscosity of the composition becomes high, making it difficult to raise the spinning draft, resulting in a marked decrease in production efficiency.

The melt spinning method is currently in practical use with resins such as polyethylene, polypropylene and polyethylene terephthalate with a spinning draft of 200 or more. The melt spinning method is applicable to dry and wet spinning methods which require a solvent. This is a method that is extremely productive in comparison. Also in the present invention, melt drafting is performed in a spinning draft in the range of 200 to 600.
The higher the spinning draft is, the higher the production efficiency is, which is preferable. However, the spinning draft is inevitably limited from the viewpoint of the strength of the composition, and the upper limit is over 600. or,
Similar to the spinning draft, the higher the spinning speed is, the higher the production efficiency is. However, as described above, the production speed is within a practical production range of 1000 to 4000 m / min including the limitation from the viewpoint of the strength of the composition. Is. The present invention is a biodegradable cellulose acetate long fiber melt-spun using the resin composition described above, to obtain a fiber in a state that the fiber breakage rate during extrusion melt-spinning is extremely small. The productivity is very high, and the obtained long fibers are spun into a woven fabric, or the obtained web is heat-embossed into a spunbonded nonwoven fabric, which is suitable for sanitary materials, packaging materials, etc. Used for.

[0021]

The present invention will be described in more detail with reference to the following examples, but of course the present invention is not limited thereto. In Examples and Comparative Examples,% means% by weight.

Example 1 A mixture of 13% of dissolved pulp from softwood wood, 2% of sulfuric acid, 35% of acetic anhydride and 50% of glacial acetic acid per total dry weight was acetylated at a temperature of 36 ° C. for 3 hours to react. After that, the reaction product is neutralized with potassium acetate, then hydrolyzed at a temperature of 60 ° C. for 3 hours, purified and dried to obtain a cellulose acetate flake having an acetylation degree of 54% and an average degree of polymerization of 180. Was pulverized with a pulverizer. Next, based on the total dry weight, 55% of this cellulose acetate, polycaprolactone (manufactured by Daicel Chemical, trademark:
Praxel 4H) 10%, caprolactone triol having an average molecular weight of 550 (manufactured by Daicel Chemical, trademark: Praxel 305) 30%, polyethylene adipate having an average molecular weight of 1000 (manufactured by Nippon Polyurethane, trademark: Nipporan 40)
02) The mixture consisting of 5% was mixed with a Henschel mixer and then mixed with a kneader at a temperature of 180 ° C. and 30 rpm for 10 minutes.
Kneaded for minutes.

The kneaded product was then fed to an extruder, melted at a temperature of 200 ° C., extruded as a strand having a width of 3 mm, cooled, and then cut into a length of 3 mm to obtain pellets. The pellets are dried in a hot air dryer heated to a temperature of 80 ° C. for 10 hours, then taken out and supplied to an extruder type melt spinning machine at a spinning temperature of 212 ° C.
With a hole diameter of 0.3 mm, and the ejected filament filament group is drawn by an ejector, stretched and opened, and spinning speed is 2850 m / min.
It was wound up at 60. The fineness of the long fibers was 2.1 denier.

The yarn breakage rate during spinning, the yarn strength and biodegradability of the obtained long fibers were evaluated by the following methods. Evaluation method (1) Breakage rate The number of breaks per hour was measured while winding the fibers obtained by melt spinning. (2) Yarn Strength It was carried out according to the method described in JIS L1013. (3) Biodegradability The melt-spun filaments are partially thermo-bonded by self-bonding with an embossing roll so that the shape can be retained, and then in the open soil in Koto-ku, Tokyo (1 Shinonome, Koto-ku, Tokyo) No. 10-6, Shin-Oji Paper Co., Ltd. Shinonome Research Center site 25)
It was embedded at a depth of cm, taken out after 6 months, and evaluated in three stages from the morphological change and the weight change. ◯: Both morphological change and weight reduction are remarkable, Δ: Morphological change and weight change are observed, ×: No morphological change and weight change are observed.

Example 2 55% of the same cellulose acetate as in Example 1 based on the total dry weight, polycaprolactone (trade name: manufactured by Daicel Chemical Co., Ltd .:
Praxel 4H) 15%, caprolactone triol having an average molecular weight of 550 (manufactured by Daicel Chemical Co., Ltd., trademark: Praxel 305) 25%, and a mixture of polyethylene glycol having an average molecular weight of 600 (5%, Sanyo Kasei; trademark: PEG600), Long fibers were produced and wound in the same manner as in Example 1 except that melt spinning was performed at a spinning temperature of 210 ° C., and the obtained long fibers were tested. The fineness of long fibers is 2.
It was 0 denier.

Example 3 Based on the total dry weight, 50% of the same cellulose acetate as in Example 1, 15% of cellulose propionate prepared by a conventional method (substitution degree 1.9, degree of polymerization 65), average molecular weight 55.
0% caprolactone triol (trade name: Praxel 305, manufactured by Daicel Chemical Industry Co., Ltd.) 25%, average molecular weight 1000
A long fiber was produced and wound in the same manner as in Example 1 except that melt-spinning was performed at a spinning temperature of 210 ° C. using a mixture of 10% of polyethylene adipate (trademark: Nippon Polyurethane 4002, manufactured by Nippon Polyurethane Co., Ltd.). The long fibers obtained were tested. The fineness of the long fibers was 2.2 denier.

Comparative Example 1 60% of the same cellulose acetate as in Example 1, 35% of caprolactone triol having an average molecular weight of 550 (Daicel Chemical Industries, trade name: Praxel 305), and polyethylene adipate having an average molecular weight of 1000 (Nippon Polyurethane) based on the total dry weight. Manufactured by Trademark: Nipporan 4002) 5% was used, except that melt spinning was performed at a spinning temperature of 215 ° C., long fibers were produced in the same manner as in Example 1, and the obtained long fibers were wound. Tested. The fineness of long fibers is 2.
It was 0 denier.

Comparative Example 2 Based on the total dry weight, 60% of the same cellulose acetate as in Example 1, 35% of caprolactonetriol having an average molecular weight of 550 (trade name: Praxel 305 manufactured by Daicel Chemical Co., Ltd.) and polyethylene glycol having an average molecular weight of 600 (Sanyo Kasei Co., Ltd.) Manufactured under the trademark: PEG600) 5%, a long fiber was produced and wound in the same manner as in Example 1 except that melt spinning was performed at a spinning temperature of 215 ° C., and the obtained long fiber was tested. did. The fineness of the long fibers was 2.3 denier.

Comparative Example 3 Cellulose acetate (60%), caprolactone triol having an average molecular weight of 550 (trade name: Praxel 305, manufactured by Daicel Chemical Co., Ltd.) having an average molecular weight of 550, and polyethylene adipate having an average molecular weight of 1000 (Japanese Polyurethane) were used. Manufactured under the trademark: Nipolan 4002) 10%, using a mixture consisting of 10%, except that melt spinning was performed at a spinning temperature of 216 ° C., long fibers were produced in the same manner as in Example 1,
The long fibers obtained were wound and tested. The fineness of the long fibers was 2.0 denier.

Table 1 shows the blending amount of cellulose acetate, the type and blending amount of biodegradable polymer, the type of plasticizer, the average molecular weight and the blending amount used in Examples and Comparative Examples.

[0031]

[Table 1]

Table 2 shows the results of spinning conditions, yarn breakage rate during spinning, yarn strength and biodegradability.

[0033]

[Table 2]

As can be seen from Tables 1 and 2, in the fiber production method of the present invention, the spinning draft is 400 or more (4
Even when high (60-510), there is almost no yarn breakage during spinning,
Cellulose acetate fibers can be efficiently produced, and the obtained fibers have high yarn strength and excellent biodegradability (Examples 1 to 3). On the other hand, in the conventional method (Comparative Examples 1 to 3) in which the biodegradable polymer is not blended, when the spinning draft is increased to 400 or more (440 to 480),
The yarn breakage rate during spinning increases, stable melt spinning cannot be performed, and productivity is poor. Further, the obtained fiber is excellent in biodegradability but inferior in yarn strength.

[0035]

INDUSTRIAL APPLICABILITY The present invention provides a cellulose acetate fiber having excellent biodegradability and fiber strength, and a spinning temperature of 19
The effect of providing a method for producing a cellulose acetate fiber having an extremely excellent melt spinnability at 0 to 230 ° C. and a spinning draft of 200 or more is exhibited.

Claims (3)

[Claims] 1. A biodegradable cellulose acetate fiber obtained by melt-spinning a biodegradable resin composition containing cellulose acetate, a biodegradable polymer and a plasticizer as main components, wherein the biodegradable resin composition is Cellulose acetate having an acetylation degree of 30 to 56% and an average degree of polymerization of 150 to 250 is 45 to 65% by weight based on the total dry weight, a biodegradable polymer is 5 to 25% by weight based on the total dry weight, and the average molecular weight is 400-20
No. 00 biodegradable polyester polyol, or the above polyester polyol, and an average molecular weight of 400 to 1000.
A biodegradable cellulose acetate fiber characterized by comprising 25 to 40% by weight based on the total dry weight of a plasticizer comprising a mixture with the biodegradable polyether polyol. 2. The biodegradable cellulose acetate fiber according to claim 1, wherein the biodegradable polymer constituting the biodegradable resin composition is an aliphatic polyester. 3. The biodegradable resin composition according to claim 1 or 2, wherein a spinning temperature of 190 to 230 ° C. and a spinning draft 20.
A method for producing a biodegradable cellulose acetate fiber, which comprises melt spinning at 0 to 600.