JP2000096416A - Biodegradable nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a biodegradable nonwoven fabric completely degradable by a microorganism in a compost, wet soil, activated sludge-containing water, sea water, etc., capable of controlling its biodegradation rate, widely usable for medical treatment, domestic use, industrial base, agricultural material, etc. SOLUTION: In this biodegradable nonwoven fabric obtained by heating and melting a biodegradable thermoplastic polyester resin, extruding the melt from a great number of spinneret holes, spinning, drawing a spun continuous filament group by a high-speed high-pressure air from an ejector, collecting and piling a drawn filament on a substrate to form a web, subjecting the web to heat embossing treatment to give a nonwoven fabric having a thermally fused zone, 0.1-5.0 wt.% based on the resin weight of an antimicrobial agent is added to the thermoplastic polyester to give a biodegradable nonwoven fabric. The continuous filament is a sheath-core conjugate filament, the sheath component contains 0.1-5.0 wt.% of the antimicrobial agent based on the resin weight and the sheath component of the conjugate filament has 10-100% based on the cross section area of the filament.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a sanitary system which can be completely decomposed by microorganisms in compost, wet soil, water containing activated sludge, seawater, etc., and whose biodegradation rate can be controlled. The present invention relates to a biodegradable nonwoven fabric that can be widely used as a base material for medical supplies, clothing, a base material for households, industrial supplies, agricultural materials, and the like.

[0002]

2. Description of the Related Art Spunbonded nonwoven fabrics using long fibers as constituent fibers are used for various purposes because they are higher in strength and relatively inexpensive than short fiber nonwoven fabrics containing short fibers as constituent fibers. . As a fiber material constituting the spunbonded nonwoven fabric, polymers such as polyethylene, polypropylene, polyester, and polyamide are generally used. However, spunbonded nonwoven fabrics made of these materials are not biodegradable by microorganisms and the like, and are chemically very stable under ordinary natural environments.

[0003] Therefore, the disposable non-woven fabric, after use,
At present, it is disposed of by disposal or landfill. Incineration is widely performed in Japan, but not only requires a great deal of expense, but also, for example, in the case of nylon-based long-fiber nonwoven fabric, which is a polyamide, there is a risk of generating a toxic gas such as cyanide gas. Because
Pollution caused by waste plastics is being generated, and how to solve the problem of waste plastics treatment is a major social problem in terms of protection of the natural environment and living environment.

[0004] On the other hand, there is a problem that landfills remain in the original state for a long time in soil because the raw materials are chemically stable. As a method for solving such a problem, a new spunbonded nonwoven fabric that is naturally degraded in a short period of time by using a biodegradable material has been demanded.

[0005] Examples of the biodegradable polymer include polysaccharides such as chitin, proteins and polypeptides (polyamino acids) such as cut gut (intestinal tract) and regenerated collagen, and poly-3-hydroxybutyrate produced by microorganisms in nature. And poly-3-hydroxyvalerate and poly-3-
Microbial polyesters such as hydroxycaprolate,
Synthetic aliphatic polyesters such as polyglycolide and polylactide are known.

However, when producing fibers from these polymers, there is a problem that the melt spinnability, which is essential for spunbonded nonwoven fabrics, is very poor, and processing cannot be carried out using a commonly used spunbonded nonwoven fabricating apparatus. In addition, since the cost of the material is extremely high, it is unsuitable as a general disposable living material such as a sanitary material such as a diaper or a cover stock of a sanitary article, a wiping cloth, and a packaging material.

To solve the above problems, Japanese Patent Laid-Open No.
No. 57953 proposes a spunbonded nonwoven fabric made of polyethylene containing 3 to 30% of polycaprolactone as a biodegradable polymer. However, since polyethylene does not decompose semipermanently, it cannot be said to be a biodegradable spunbond nonwoven fabric in the original sense.

Japanese Patent Application Laid-Open No. Hei 5-214648 discloses that poly-ε-caprolactone and / or poly-β-
Spunbond nonwoven fabrics made of polopiolactone have been proposed. In this case, the microorganism could be completely degraded, but the melting point of poly-ε-caprolactone was 60%.
C., the melting point of poly-β-polopiolactone is 100
° C and poor thermal stability, which is not suitable as a practical material.

Further, in Japanese Patent Application Laid-Open Nos. 7-48768 and 7-34369, the present inventors further disclose,
JP-A-8-60513 has proposed a spunbonded nonwoven fabric made of an aliphatic polyester resin, which comprises a glycol and an aliphatic dicarboxylic acid or a derivative thereof as constituent units. Although this non-woven fabric substantially solves the above problems, it has not been practically obtained yet that satisfies both spinnability and biodegradability.

That is, as the aliphatic polyester suitable for melt spinning and usable for spunbonded nonwoven fabric, for example, an aliphatic polyester polymer synthesized from 1,4-butanediol and succinic acid is used. In the case of a resin such as butylene succinate, the melt spinnability is good, and a biodegradable nonwoven fabric having excellent strength and texture can be obtained.However, depending on the use, since the melting point of the resin is 115 ° C. or less, particularly for industrial materials, Not only is the heat resistance insufficient, but also the control of the biodegradation rate is difficult.

Furthermore, L-lactic acid or D-lactic acid unit is
Resins such as a polylactic acid polymer containing at least mol% have a good melt spinnability, and a nonwoven fabric with excellent strength can be obtained.
Since the nonwoven fabric is hard, it is not suitable for sanitary materials such as diapers and cover stocks for sanitary products, wipes, packaging materials, and the like, and has a drawback that it is difficult to control the biodegradation rate.

Japanese Patent Application No. 8-198615 discloses a polybutylene succinate polymer having a sheath component synthesized from 1,4-butanediol and succinic acid.
% Of 1,4-butanediol and 40 to 0% by weight of a polybutylene succinate-adipate copolymer synthesized from succinic acid and adipic acid, wherein the core component is the polybutylene succinate-adipate. A core-sheath type composite long-fiber nonwoven fabric comprising 100% by weight of a copolymer is disclosed. This biodegradable nonwoven fabric can control the biodegradation rate in soil and seawater to some extent, but it is difficult to control the biodegradation rate under conditions such as compost that promote the biodegradation rate. There was a disadvantage.

[0013]

The biodegradable nonwoven fabric needs to have a different decomposition rate and a different life depending on the purpose, application and situation. Accordingly, an object of the present invention is to provide a biodegradable nonwoven fabric whose biodegradation rate can be changed over a wide range, that is, a biodegradable nonwoven fabric whose degradability can be freely changed over a wide range.

[0014]

Means for Solving the Problems In view of the present situation, the present inventor has conducted intensive studies on a nonwoven fabric whose biodegradation rate can be controlled. As a result, the biodegradable resin can be obtained by including an antibacterial agent. The present inventors have found that the biodegradation rate of a nonwoven fabric can be controlled and completed the present invention.

Furthermore, L-lactic acid or D-lactic acid unit is
Focusing on the fact that a polylactic acid polymer containing 0 mol% or more is degraded by microbial degradation and hydrolysis, as a result of intensive studies, the sheath component of the core-sheath type composite filament was L-lactic acid or D-lactic acid.
-Decomposition mainly starts from hydrolysis by kneading an antibacterial agent into a polylactic acid polymer containing 80 mol% or more of lactic acid units, and after the antibacterial agent falls off by hydrolysis, degradation by microorganisms Heading to get started,
The present inventors have found that a nonwoven fabric whose biodegradability can be controlled can be obtained by adjusting the antibacterial agent content and the sheath component ratio, and have completed the present invention.

That is, according to the present invention, the sheath component comprises a polylactic acid polymer containing at least 80 mol% of L-lactic acid or D-lactic acid unit containing 0.1 to 5.0% of antibacterial agent per resin weight. The core component is composed of a polymer obtained by increasing the molecular weight of a polybutylene succinate polymer synthesized from 1,4-butanediol and succinic acid by urethane bonds, and the sheath component of the composite long fiber has a fiber cross-sectional area of Per 10
It is a nonwoven fabric whose biodegradation rate can be controlled by being 100%.

In the first aspect of the present invention, a thermoplastic biodegradable aliphatic polyester resin is heated and melted, extruded from a number of die holes and spun, and a spun continuous filament filament group is spun from an ejector at high speed and high pressure. Stretched by air, collected and deposited on a support to form a web, and the web is heat-embossed to form a heat-sealed area. The present invention relates to a biodegradable nonwoven fabric, characterized in that an antimicrobial agent is contained in a group polyester resin in an amount of 0.1 to 5.0% by weight per resin weight.

A second aspect of the present invention is that the continuous filament fiber is a core-sheath composite filament, and the sheath component contains an antibacterial agent in an amount of 0.1 to 5.0% by weight based on the weight of the resin. The biodegradable nonwoven fabric according to the first aspect of the present invention, wherein the sheath component of the fiber is 10 to 100% per fiber cross-sectional area.

The third aspect of the present invention is that the sheath component is composed of a polylactic acid polymer containing at least 80 mol% of L-lactic acid or D-lactic acid units, and the core component is composed of 1,4-butanediol and succinic acid. The present invention relates to the biodegradable nonwoven fabric according to the first or second aspect of the present invention, comprising a polymer obtained by increasing the molecular weight of a polybutylene succinate polymer to be synthesized by a urethane bond.

A fourth aspect of the present invention is characterized in that the antibacterial agent is obtained by adsorbing silver ions on synthetic zeolite, which is a crystal of alumina and silica.
It relates to the biodegradable nonwoven fabric according to 2 or 3.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The aliphatic polyester resin usable for the core component of the present invention is not particularly limited as long as it has biodegradability, but it is particularly preferred to use 1,4-butanediol and succinic acid. Isocyanate is further added to the polybutylene succinate polymer synthesized from, and a polyurethane bond is formed between the polybutylene succinate polymers. More preferably, the number average molecular weight is 10,000 or more and the melting point is 110 to 120 ° C. Within the range and JIS K
7210 (190 ° C., 2.16 kg
The melt flow rate measured in (load) is 10 to 70 g /
It is preferably in the range of 10 minutes.

That is, the melt flow rate is 10 g / 1
The urethane condensation of polybutylene succinate of less than 0 minutes has too high a melt viscosity, so that melt spinning at a high speed is not easy unless the melt temperature is increased. May easily occur and may not be suitable for operation. Conversely, the melt flow rate is 70 g
If it exceeds / 10 minutes, thread breakage tends to occur, and not only the feeling of the biodegradable nonwoven fabric obtained deteriorates, but also the strength may decrease.

If necessary, a polybutylene succinate polymer synthesized from 1,4-butanediol and succinic acid may be converted into a polymer having a high molecular weight by a urethane bond.
For example, in addition to antioxidants, heat stabilizers, ultraviolet absorbers,
Various additives such as a lubricant, a wax agent, a coloring agent, and a crystallization accelerator can be added within a range that does not impair the effects of the present invention.

The polybutylene succinate polymer synthesized from 1,4-butanediol and succinic acid further added with isocyanate to form a polyurethane bond between the polybutylene succinate polymers is hydrophilic, Although the resin contains water, spinning in the state of containing water causes decomposition of the resin, so that it is necessary to perform a drying treatment prior to spinning. The water content of the resin is at most 0.2% by weight, preferably at most 0.05% by weight.

The aliphatic polyester used for the sheath component of the present invention is not particularly limited as long as it has biodegradability.
Preferably it is a polylactic acid polymer, more preferably L
-A polylactic acid polymer containing at least 80 mol% of a lactic acid unit or a D-lactic acid unit. Lactic acid monomer has optically active carbon, and therefore polylactic acid is known to have optical isomers, D-form and L-form, but when both are copolymerized, the melting point decreases, If the optical purity is too low, the melting point is too low, so that good spinnability, one of the objects of the present invention, cannot be obtained.

The optical purity (ratio of L-form or D-form) of the lactic acid unit in the polylactic acid polymer used for the sheath component is preferably 80 mol% or more, more preferably 95 mol% or more, and further preferably 98 mol%. That is all.

In general, L-lactic acid is produced by fermentation to produce L-form. Therefore, L-lactic acid is industrially more easily available in large quantities and at low cost. Is the main subject. However, D-
Even with a polymer mainly composed of lactic acid, the same physical properties as those of L-lactic acid can be obtained.

The above-mentioned polylactic acid polymer used in the present invention is also similar to the one obtained by bonding polybutylene succinate to urethane, and the method described in JIS K 7210 (1)
A melt flow rate measured at 90 ° C. under a load of 2.16 kg) in the range of 10 to 70 g / 10 minutes is suitable. Polylactic acid having a melt flow rate of less than 10 g / 10 minutes has too high a melt viscosity, so that melt spinning at a high speed is not easy unless the melt temperature is increased, and spinning at a high temperature causes stains on a die surface. And it is not suitable for operation.
On the other hand, if the melt flow rate exceeds 70 g / 10 minutes, thread breakage frequently occurs, and not only the formation of the obtained nonwoven fabric deteriorates, but also the strength decreases, which is not suitable.

Further, the difference between the melt flow rate of polylactic acid used for the sheath component and the melt flow rate of the polybutylene succinate used for the core component which is urethane-bonded is 0 to 30 g / 10 minutes or less. Is preferred. If the difference exceeds 30, distortion due to excessively different melt-elongation properties will deteriorate spinnability, which is not suitable.

The polylactic acid resin may be, if necessary, similar to polybutylene succinate bonded to urethane, for example, an antioxidant, a heat stabilizer, an ultraviolet absorber, a lubricant, a wax, Various additives such as a coloring agent and a crystallization accelerator can be added within a range that does not impair the effects of the present invention.

A polylactic acid polymer containing at least 80 mol% of L-lactic acid units or D-lactic acid units is also obtained by adding an isocyanate to a polybutylene succinate polymer synthesized from 1,4-butanediol and succinic acid. As in the case of polyurethane bonded between polybutylene succinate polymers, it is hydrophilic and contains water in the resin. Therefore, it is necessary to perform a drying treatment prior to spinning. The water content of the resin is at most 0.2% by weight, preferably at most 0.05% by weight.

Further, L-lactic acid or D-lactic acid used for the sheath component
Polylactic acid polymer containing 80 mol% or more of lactic acid units,
An antibacterial agent having an average particle size of 0.1 to 2.0 µm is contained in an amount of 0.5 to 5.0% by weight of the resin.

As the kind of the antibacterial agent, the average particle size is 0.1
There is no particular problem as long as it is in the range of ~ 2.0 μm, but preferably, it is heated and melted and extruded from a large number of die holes and spun,
When the spun continuous filament filament group is drawn from the ejector with high-speed and high-pressure air, the silver ion is converted into a synthetic zeolite which is a crystal of alumina and silica having good spinnability if the content is within a certain range. Adsorbed.

An alumina having an average particle size of less than 0.1 μm;
Synthetic zeolite, which is a crystalline form of silica, having silver ions adsorbed thereon is difficult to adjust and causes an increase in cost, which is not suitable.

If the average particle size exceeds 2.0 μm, it is not suitable because good spinnability essential for the production of long-fiber nonwoven fabric cannot be obtained. The average particle size was measured using a laser diffraction particle size distribution analyzer “SALD-2” manufactured by Shimadzu Corporation.
000J ”, the peak of the obtained particle size distribution was taken as the average particle size, measured at n = 5, and the average value was calculated to obtain the average particle size of the antibacterial agent.

The antibacterial agent having the above-mentioned average particle size is added to a polylactic acid polymer containing 80 mol% or more of L-lactic acid or D-lactic acid units used as a sheath component in an amount of 0.1 to 5.
0% is contained.

The content of the antibacterial agent per resin weight is 0.1
%, It is not suitable because the effect of reducing the biodegradation rate of the nonwoven fabric by the antibacterial agent is not sufficiently exhibited. On the other hand, if the content of the antibacterial agent per resin weight exceeds 5.0%, good spinnability essential for producing a spunbonded nonwoven fabric cannot be obtained, which is not suitable. The method of incorporating the antimicrobial agent into the resin is not particularly limited, but a method of kneading the resin is generally used.

The kneading is performed, for example, by combining a “Labo Plastomill 50C150”, “Segment Extruder”, and “Cold Cut Pelletizer PETEC” manufactured by Toyo Seiki Seisaku-sho, and mixing a mixture obtained by dry blending polylactic acid and an antibacterial agent at a temperature of 210 ° C. The mixture was kneaded at ℃ and pelletized. In addition,
Cooling was performed by air cooling.

When a nonwoven fabric is produced, a polymer obtained by increasing the molecular weight of a polybutylene succinate polymer synthesized from 1,4-butanediol and succinic acid by a urethane bond, or L-lactic acid or D When a polylactic acid polymer containing 80 mol% or more of lactic acid units is melted by heating and spinning, the melting temperature is 5 degrees below the melting point of the resin.
Increase by 0-135 ° C. When the melting temperature is higher than the melting point of the polymer by less than 50 ° C., the viscosity of the melted resin is high, and melt spinning at a high speed becomes difficult unless the melting temperature is increased. Dirt is likely to occur and is not suitable for operation. Conversely, if the melting temperature is higher than the melting point of the resin by more than 135 ° C., the temperature difference from the melting point of the resin is too large, so that the cooling becomes difficult when spinning the resin from a large number of spinnerets of the extrusion spinning machine.
Not only is it easy to cause fusion between fibers and yarn breakage,
The stability of the resin may be reduced, and decomposition may occur.

In particular, when the core-sheath composite spinning is performed, it means that the respective resins of the core component and the sheath component are spun at substantially the same temperature, and the difference between the melting temperatures of the core component and the sheath component is ± 1. .
Acceptable up to 5 ° C, preferably ± 10 ° C. If the difference between the melting temperatures of the core component resin and the sheath component resin exceeds 3 ° C. in absolute value, cooling of the composite yarn after melt extrusion does not proceed smoothly, and distortion due to uneven cooling of the yarn is caused. , A good spinnability cannot be realized, and as a result, yarn breakage occurs frequently and the nonwoven fabric becomes non-uniform.

In the nonwoven fabric comprising the biodegradable conjugate long fibers according to the present invention, the ratio of the sheath component to the fiber cross-sectional area is 10 to 100%. If the component ratio of the sheath is less than 10%, it is difficult to sufficiently control the biodegradation rate, so that it is not suitable.

The polylactic acid polymer containing at least 80 mol% of L-lactic acid or D-lactic acid units used in the sheath component of the present invention is hydrolyzed not only by soil and water but also by moisture in the air. Go. Therefore, even if an antibacterial agent is present in the sheath component, the decomposition of the nonwoven fabric is started by hydrolysis, and the biodegradation is partially and gradually started by the antibacterial agent falling off by hydrolysis. Therefore, the biodegradation rate can be arbitrarily controlled by controlling the antibacterial agent content and the ratio of the sheath component per fiber cross-sectional area.

The conjugate long fibers of the present invention can be obtained by using a conventionally known melt spinning apparatus for conjugate fibers. After being extruded from the spinneret of the melt extrusion spinning machine and spun, it is drawn by high-speed air by an ejector, stretched, and then a number of long fiber filaments formed are applied to a collision plate to triboelectrically charge and repulsive force by electric charge To open. In this case, corona discharge treatment can be performed as a charging method. A number of uniformly opened filaments are then deposited on a support.

The average fineness of the long fibers of the present invention is in the range of 1 to 10 denier. If the average fineness of the long fibers exceeds 10 denier, the fiber diameter becomes too large, and the flexibility and formation of the obtained nonwoven fabric are deteriorated. vice versa,
If the average fineness of the long fibers is less than 1 denier, the spinnability becomes poor, so that it is not suitable.

In the present invention, a large number of long fibers accumulated on a support are self-fused at regular intervals by a heat embossing treatment for the purpose of maintaining a sheet-like form and imparting strength. Create an area. The self-fusing area is formed by introducing the web between the heated uneven roll and the smooth roll, applying heat and pressure treatment, and fusing the portion corresponding to the convex portion of the uneven roll. .

In this case, the temperature of the roll depends on the L-
The temperature is 5 to 50C lower than the melting point of the polylactic acid polymer containing 80 mol% or more of lactic acid or D-lactic acid units. If the difference between the roll temperature and the melting point of the resin is less than 5 ° C., the fibers will adhere to the roll during thermocompression treatment by the roll, causing a manufacturing trouble. Conversely, the difference between the roll temperature and the melting point of the resin is 50
If the temperature exceeds ℃, the formation of the self-fused portion becomes insufficient, and the strength of the nonwoven fabric is remarkably reduced.

The linear pressure when the thermocompression bonding is performed with the uneven roll and the smooth roll is 10 to 80 kg / cm. If the linear pressure is less than 10 kg / cm, the self-bonding area by the thermocompression bonding process is insufficiently formed, and if it exceeds 80 kg / cm, the long fiber is cut by the convex portion of the uneven roll during the thermocompression bonding process. All of these are not suitable because the strength of the nonwoven fabric is reduced.

In the present invention, the area of each self-fusion zone is preferably in the range of 0.03 to ⁴ mm ² . If the area of the self-bonding area is less than 0.03 mm ² , the strength of the obtained nonwoven fabric is insufficient, which is not suitable. Conversely, if the area of the self-fused area exceeds 4 mm ² , the obtained nonwoven fabric becomes too hard, and the flexibility is reduced, which is not suitable.

The total area of the self-fusing area is preferably 2 to 30% of the total surface area of the biodegradable nonwoven fabric. If the total area of the self-fused area is less than 2%, the strength of the obtained nonwoven fabric is insufficient, which is not suitable. On the other hand, if the self-fused area exceeds 30%, the obtained nonwoven fabric becomes too hard and the flexibility is lowered, which is not suitable.

The basis weight of the nonwoven fabric in the present invention is not particularly specified, and can be arbitrarily selected.

As described above, the sheath component is composed of a polylactic acid polymer containing at least 80 mol% of an L-lactic acid or D-lactic acid unit containing 0.1 to 5.0% of an antibacterial agent per resin weight. The core component is composed of a polymer obtained by increasing the molecular weight of a polybutylene succinate polymer synthesized from 1,4-butanediol and succinic acid by urethane bonds, and the sheath component of the composite long fiber has a fiber cross-sectional area of Per 10
A biodegradable nonwoven fabric characterized by being 100% has excellent spinnability and spreadability during production, has controllable biodegradability, and has excellent flexibility and texture while having high strength. Therefore, it can be suitably used as a sanitary material, a medical substrate, a clothing substrate, a household substrate, an industrial substrate, and the like.

[0052]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted thereto. In Examples and Comparative Examples,% is% by weight unless otherwise specified.

Example 1 As a core component, a polybutylene succinate polymer synthesized from 1,4-butanediol and succinic acid having a melt flow rate of 31 g / 10 minutes and a melting point of 118 ° C. was converted to a high molecular weight by a urethane bond. A polymer (manufactured by Showa Polymer Co., Ltd., trade name: Bionore) is prepared, and as a sheath component, synthetic zeolite, which is a crystal of alumina and silica having an average particle diameter of 1.1 μm, is made to adsorb silver ions (Shinagawa Fuel Co., Ltd.) L- having a melt flow rate containing 4.8% (trade name, manufactured by Zeomic Co., Ltd.) at a melt flow rate of 20 g / 10 min and a melting point of 163 ° C.
Polylactic acid polymer containing 80 mol% or more of lactic acid or D-lactic acid unit (manufactured by Kanebo Gosen Co., Ltd., trade name: Lactron)
Was prepared.

Next, the sheath component was 50% per fiber cross-sectional area.
Using a composite spinneret in a melt extruder, the resin is heated and melted at 220 ° C., extruded from a large number of micropores, spun, and the spun filament group is ejected with high-speed air by an ejector. The wire is stretched and opened while being collected, and collected on a moving wire-made collecting support.
The web was deposited and formed.

Next, this laminated web was introduced between the uneven roll heated to 135 ° C. and the smooth roll, and a linear pressure of 30 kg was applied.
A biodegradable nonwoven fabric was obtained by fusing a portion corresponding to the convex portion of the concave / convex roll at / cm. The area of each self-fusion zone was 0.12 mm ² , and the total area of the self-fusion zone was 4 area%. The fineness of the obtained nonwoven fabric was 2.0 denier and the basis weight was 98 g / m ² .

The obtained biodegradable nonwoven fabric was tested by the following test methods to evaluate its quality. Test method (1) Spinnability Evaluated by the number of yarn breaks during melt spinning. The evaluation was based on the following five levels. 5 points: No thread breakage, and spinning properties are extremely good. 4 points: There is almost no yarn breakage, and the spinnability is good. 3 points: There is a thread break, but there is no problem, and the spinnability is normal. 2 points: The thread breakage is considerably large, and the spinnability is poor. 1 point: The thread breakage is extremely large, and the spinnability is extremely poor.

(2) Biodegradation Rate (Month) A nonwoven fabric cut into a size of 10 cm × 25 cm was subjected to cow manure compost-containing soil (weight composition ratio: cow manure compost 20%, soil 76
%, Peat moss 4%), buried 100 pieces each at a depth of 15 cm, take out two pieces every month, measure the weight, and the form becomes scattered and the weight loss becomes 50% by weight or more (month) ) Was measured, and the average value was calculated as the microbial degradation rate. The resulting biodegradation rate was compared with the target degradation rate. The observation was performed for 36 months.

Example 2 A biodegradable nonwoven fabric was produced in the same manner as in Example 1 except that the antibacterial agent content was changed to 0.3%. The basis weight of the obtained nonwoven fabric was 102 g / m ² , and the fineness was 2.1 denier. The obtained nonwoven fabric was tested by the same test method as in Example 1, and its quality was evaluated.

Example 3 The antibacterial agent content was 10% and the sheath component was 10% per fiber cross-sectional area.
A biodegradable nonwoven fabric was manufactured in the same manner as in Example 1 except that the content was set to 0%. The basis weight of the obtained nonwoven fabric is 99 g /
m ² and fineness were 1.9 denier. The obtained nonwoven fabric was tested by the same test method as in Example 1, and its quality was evaluated.

Example 4 An antibacterial agent content of 10% and a sheath component of 12% per fiber cross-sectional area
%, And a biodegradable nonwoven fabric was produced in the same manner as in Example 1. The basis weight of the obtained nonwoven fabric is 100 g /
m ² and fineness were 2.0 denier. The obtained nonwoven fabric was tested by the same test method as in Example 1, and its quality was evaluated.

Comparative Example 1 A biodegradable nonwoven fabric was produced in the same manner as in Example 1 except that the antibacterial agent content was changed to 0%. The basis weight of the obtained nonwoven fabric was 102 g / m ² and the fineness was 2.2 denier. The obtained nonwoven fabric was tested by the same test method as in Example 1, and its quality was evaluated.

Comparative Example 2 A biodegradable nonwoven fabric was produced in the same manner as in Example 1 except that the antibacterial agent content was changed to 5.3%. The basis weight of the obtained nonwoven fabric was 100 g / m ² , and the fineness was 2.0 denier. The obtained nonwoven fabric was tested by the same test method as in Example 1, and its quality was evaluated.

Comparative Example 3 The antibacterial agent content was 10%, and the sheath component was 8% per fiber cross-sectional area.
A biodegradable nonwoven fabric was manufactured in the same manner as in Example 1, except that The basis weight of the obtained nonwoven fabric is 101 g / m
^{2. The} fineness was 2.1 denier. The obtained nonwoven fabric was tested by the same test method as in Example 1, and its quality was evaluated. Table 1 shows the results obtained in the examples and comparative examples.

[0064]

[Table 1]

As is clear from Table 1, when the conditions of the present invention are met, no thread breakage occurs when the resin is melt-spun by a melt extruder, and the resulting biodegradable nonwoven fabric has a biodegradable rate. Can be controlled (Examples 1 to
4).

On the other hand, is the antibacterial agent content reduced beyond the specified range (Comparative Example 1), or the ratio of the sheath component to which the antibacterial agent is added per fiber cross-sectional area is reduced beyond the specified range? (Comparative Example 3) It becomes difficult to control the biodegradation rate. On the other hand, when the antibacterial agent content is increased beyond the specified range (Comparative Example 2), the spinnability deteriorates and it becomes impossible to obtain a biodegradable nonwoven fabric stably.

[0067]

The present invention has the effect of providing a biodegradable nonwoven fabric which has excellent spinnability during production and can control the biodegradation rate.

Claims (4)

[Claims] Claims: 1. An aliphatic polyester resin having thermoplastic biodegradability is heated and melted, extruded from a number of die holes and spun, and a spun continuous filament filament group is drawn from an ejector by high-speed high-pressure air; An antibacterial agent is added to the aliphatic polyester resin in an amount of 0.1% per resin weight in a nonwoven fabric comprising a web formed by collecting and depositing on a support to form a web, and hot-embossing the web to form a heat-sealed area. ~
A biodegradable nonwoven fabric characterized by containing 5.0% by weight. 2. The continuous filament fiber is a core-sheath composite filament, and an antibacterial agent is added to the sheath component in an amount of 0.1 to 0.1% by weight of the resin.
2. The biodegradable nonwoven fabric according to claim 1, wherein the biodegradable nonwoven fabric is contained at 5.0% by weight, and a sheath component of the composite continuous fiber is 10 to 100% based on a fiber cross-sectional area. 3. A polybutylene polymer comprising a sheath component comprising a polylactic acid polymer containing at least 80 mol% of L-lactic acid or D-lactic acid units, and a core component comprising polybutylene synthesized from 1,4-butanediol and succinic acid. The biodegradable nonwoven fabric according to claim 1, comprising a polymer obtained by increasing the molecular weight of a succinate polymer by urethane bonds. 4. The method according to claim 1, wherein the antibacterial agent is obtained by adsorbing silver ions on synthetic zeolite, which is a crystal of alumina or silica, and has an average particle size of 0.1 to 2.0 μm. The biodegradable nonwoven fabric according to claim 1, 2, or 3.