JPH11269753A - Biodegradable nonwoven fabric for nursery pot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a biodegradable nonwoven fabric for nursery pots having the biodegradability and capable of optionally controlling the biodegradation rate thereof. SOLUTION: This biodegradable nonwoven fabric for nursery pots is obtained by including a carbon black having 0.1-2.0 μm average grain diameter in an amount of 0.5-20 wt.% based on the resin weight in a thermoplastic aliphatic polyester resin in the nonwoven fabric prepared by thermally melting the thermoplastic aliphatic polyester resin, extruding and spinning the resultant melt through many spinneret holes, drawing the extruded continuous filament group with high-speed and high- pressure air from an ejector, collecting and depositing the filament group on a support, forming a web, carrying out the thermal embossing treatment of formed web and forming thermally fused sections. The biodegradable nonwoven fabric for the nursery pots comprises the thermoplastic aliphatic polyester resin composed of a polymer obtained by providing a polybutylene succinate polymer synthesized from 1,4-butanediol and succinic acid with a high molecular weight through urethane bonds. Furthermore, the biodegradable nonwoven fabric for the nursery pots comprises the thermoplastic aliphatic polyester resin composed of a polylactic acid polymer containing >=80 mol.% of L-lactic acid units or D-lactic acid units.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a biodegradable nonwoven fabric for growing seedling pots, which is biodegradable and whose biodegradation rate can be arbitrarily controlled.

[0002]

2. Description of the Related Art A nonwoven fabric obtained by laminating a large number of long fibers made of a thermoplastic resin on a support and then providing a partial and regular self-fused portion on the laminated sheet is generally used. It is called spunbond nonwoven fabric. This nonwoven fabric is not only superior in productivity to other nonwoven fabrics, but also has high sheet strength and is used in a wide range. However, since thermoplastic resins used in general spunbonded nonwoven fabrics do not have biodegradability, as a disposal method, landfilling or incineration is generally performed. In addition, when a conventional spunbonded nonwoven fabric made of a thermoplastic resin is landfilled, the nonwoven fabric is not decomposed into microorganisms and the material is chemically stable, so it remains in the soil for a long time, and causes environmental problems in recent years. Cases are increasing.

[0003] On the other hand, in the case of incineration, the calorific value during incineration is high, which not only shortens the life of the incinerator, but also in the case of nylon spunbonded nonwoven fabric, harmful gas such as cyanide gas is generated. There is a possibility that it will occur. Therefore, as a method of solving such a problem, a new spunbonded nonwoven fabric which is naturally decomposed in a short period of time has been demanded.

[0004] In recent years, a great deal of research has been conducted on polymers having biodegradability as resins used for spunbonded nonwoven fabrics. Examples of this degradable polymer include polysaccharides such as cellulose and chitin, proteins such as regenerated collagen, poly-3-hydroxybutyrate, poly-3-hydroxyvalerate, and poly-hydroxylate produced by microorganisms.
Polyesters such as 3-hydroxycaprate are known.

For example, JP-A-4-57951 discloses a nonwoven fabric in which cellulosic regenerated fibers or semi-synthetic fibers are bonded with chitosan or the like. Although this nonwoven fabric has biodegradability, it not only has poor productivity but also has poor strength and water resistance as compared with a spunbonded nonwoven fabric made of polypropylene or polyethylene terephthalate resin, which is used in a wide range of fields. I have. Further, among these, poly-3-hydroxybutyrate,
Poly-3-hydroxyvalerate, poly-3-hydroxycaprate, and the like have thermoplasticity, but have poor melt spinnability required for producing a spunbonded nonwoven fabric, and cannot stably obtain a spunbonded nonwoven fabric.

As a method for obtaining a spunbonded nonwoven fabric having biodegradability, for example, Japanese Unexamined Patent Publication No. 4-57953 discloses a biodegradable nonwoven fabric composed of fibers of polyethylene containing 3 to 30% of polycaprolactone. Have been. In this case, microbes are subject to degradation
Polyethylene is the only component of polycaprolactone, and the main component of the resin, polyethylene, is not degraded by microorganisms and is chemically stable. Would. That is, this nonwoven fabric is not biodegradable but is a biodegradable nonwoven fabric, and the use of this nonwoven fabric cannot be an essential environmental protection measure.

On the other hand, Japanese Patent Application Laid-Open No. Hei 5-214648 discloses a spunbonded nonwoven fabric comprising poly-ε-caprolactone and poly-β-caprolactone.
However, spinning of a spunbonded nonwoven fabric by melt spinning of caprolactone alone is difficult to set conditions, and not only the flexibility of the obtained nonwoven fabric is insufficient, but also the poly-ε-
The melting point of caprolactone is about 60 ° C., and the melting point of poly-β-caprolactone is about 100 ° C., which has poor thermal stability and is not suitable for practical materials.

Further, Japanese Patent Application Laid-Open No. 7-48768 discloses an aliphatic polyester nonwoven fabric having a prescribed melt viscosity, and Japanese Patent Application Laid-Open No. 7-34369 discloses a nonwoven fabric comprising polyethylene succinate and polybutylene succinate. Unexamined Japanese Patent Publication No. Hei 8-6051
No. 3 proposes a spunbond 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-mentioned problems, when used for raising seedling pots, if the soil used varies depending on the region of use, variety, or season, even if the substrate has the same biodegradation rate, When there is a large difference, or when there is a lengthy period of maintaining the strength, the biodegradation rate is often adjusted with the basis weight and density, but when the processing suitability when processing into a seedling pot is unsuitable by that method There is also.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a biodegradable nonwoven fabric for growing seedling pots, which can be easily decomposed by microorganisms and the decomposition rate can be arbitrarily controlled.

[0011]

Means for Solving the Problems In view of this situation, the present inventor paid attention to the fact that the addition of carbon black to a biodegradable resin reduces the biodegradation rate. Having aliphatic polyester,
Nonwoven fabric obtained by containing carbon black having an average particle size of 0.1 to 2.0 μm in an amount of 0.5 to 20% by weight per resin weight while maintaining spinnability indispensable for producing spunbonded nonwoven fabric. The present inventors have found that the biodegradation rate of can be arbitrarily controlled, and have completed the present invention.

That is, a first aspect of the present invention is that a thermoplastic aliphatic polyester resin is heated and melted, extruded and spun from a number of die holes, and a spun continuous filament filament group is drawn from an ejector with high-speed high-pressure air. A non-woven fabric comprising a web formed by collecting and depositing on a support to form a web, and hot embossing the web to provide a partially and regularly heat-sealed area; The present invention relates to a biodegradable nonwoven fabric for raising seedling pots, wherein the resin contains 0.5 to 20% by weight of carbon black having an average particle size of 0.1 to 2.0 μm per resin weight.

A second aspect of the present invention is that the thermoplastic aliphatic polyester resin comprises a polybutylene succinate polymer synthesized from 1,4-butanediol and succinic acid, which has a high molecular weight by urethane bonds. The present invention relates to a biodegradable nonwoven fabric for a nursery pot according to the first aspect of the present invention.

A third aspect of the present invention is characterized in that the thermoplastic aliphatic polyester resin comprises a polylactic acid polymer containing at least 80 mol% of an L-lactic acid unit or a D-lactic acid unit. And a biodegradable nonwoven fabric for raising seedling pots.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The thermoplastic aliphatic polyester resin used in the spunbonded nonwoven fabric of the present invention needs to have good spinnability essential for the production of a spunbonded nonwoven fabric. As an aliphatic polyester having good spinnability, a polybutylene succinate polymer synthesized from 1,4-butanediol and succinic acid is further added with an isocyanate, and urethane polymerization is performed between the polybutylene succinate polymers. Or a polylactic acid polymer containing at least 80 mol% of L-lactic acid units or D-lactic acid units.

More specifically, an isocyanate is added to a polybutylene succinate polymer synthesized from 1,4-butanediol and succinic acid, and urethane polymerization is performed between the polybutylene succinate polymers. And has a number average molecular weight of 10,000 or more and a melting point of 110 to 110.
A temperature of 190 ° C. under a load of 2.16, which is in the range of 120 ° C. and measured by the method described in JIS K 7210
The melt flow rate under the condition of kg is 15 to 70 g / 1.
It is in the range of 0 minutes, and the one marketed under the trade name of Bionole (manufactured by Showa Polymer Co., Ltd.) is used.

If the melt flow rate is less than 15 g / 10 minutes, the melt viscosity is too high, and the texture of the obtained nonwoven fabric becomes hard, which is not suitable. Conversely, if the melt flow rate exceeds 70 g / 10 minutes, thread breakage is likely to occur in the spinning step, and not only the texture of the obtained long-fiber nonwoven fabric will decrease, but also the strength will decrease, which is not suitable.

When producing a spunbonded nonwoven fabric, the aliphatic polyester resin is heated and melted in an extrusion spinning machine, and the melting temperature when spinning is 5 degrees below the melting point of the resin.
Preferably, the temperature is increased by 0 to 135 ° C. When the difference between the melting temperature and the melting point of the polymer is less than 50 ° C., the viscosity of the melted resin is so high that it may not be suitable for spinning. 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 the fibers and breakage of the yarn, but also the stability of the resin is reduced, and there is a possibility that decomposition occurs.

Further, the aliphatic polyester resin is hydrophilic, and contains water in the resin. However, when the spinning is performed in a state containing water, the resin is decomposed, so that the resin is dried before spinning. Processing needs to be performed. The water content of the resin is at most 0.2% by weight, preferably at most 0.05% by weight.

The polylactic acid polymer is a polylactic acid polymer containing at least 80 mol% of L-lactic acid units or D-lactic acid units. Lactic acid monomers have optically active carbon, and it is known that polylactic acid has optical isomers, D-form and L-isomer. If the purity is too low, the melting point is too low and the thermal stability is poor, making it unsuitable as a practical material. Therefore, the optical purity (the ratio of L-form or D-form) of the lactic acid unit in the polylactic acid polymer used is preferably at least 80 mol%, more preferably at least 95 mol%, even more preferably at least 98 mol%.

Generally, 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, and the polylactic acid polymer used in the present invention is usually L-lactic acid. -It is mainly composed of lactic acid. However,
Even with a polymer mainly composed of D-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 also has a melt flow rate (MFR) of 10 to 10 as measured by the method described in JIS K 7210 (200 ° C .: 2.16 kg load) similarly to the above-mentioned resin. It is in the range of 70 g / 10 minutes, and the trade name is Lactron (manufactured by Kanebo Gosen)
What is marketed as is used. That is, MF
Polylactic acid having an R of less than 10 g / 10 minutes is not preferred because the melt viscosity is too high and the spinnability deteriorates. Conversely, if the MFR exceeds 70 g / 10 minutes, not only is the spinnability deteriorated, but also the strength of the obtained nonwoven fabric is reduced, which is not suitable.

Further, the polylactic acid polymer is hydrophilic,
Although the resin contains water, spinning in a state 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.

In the present invention, carbon black having an average particle diameter in the range of 0.1 to 2.0 μm is added to these resins in an amount of 0.5 to 20% by weight based on the weight of the resin. Carbon black is used not only for black pigments but also for agricultural purposes, for example, when buried in soil such as seedling raising pots, it is easy to absorb geothermal heat and not only has the effect of improving the heat retention of plant roots, but also carbon black. The added nonwoven fabric has the characteristic that the biodegradation rate is slow.

The average particle size of carbon black is 2.0 μm
If it is larger than, it is not suitable because good spinnability indispensable for production of a spunbonded nonwoven fabric cannot be obtained. Conversely, if the average particle size is less than 0.1 μm, it becomes difficult to adjust the carbon black, and this is not suitable because it causes an increase in cost. The average particle size was measured using a laser diffraction particle size distribution analyzer “SALD-2000” manufactured by Shimadzu Corporation.
Using "J", the peak of the obtained particle size distribution was defined as the average particle size, and the average value was measured by measuring at n = 5 to obtain the average particle size of the carbon black.

If the amount of carbon black added per resin weight is less than 0.5% by weight, the effect of reducing the biodegradation rate of the non-woven fabric by carbon black is not sufficiently exhibited, which is not suitable. Conversely, if the amount of carbon black added per resin weight is 20% by weight or more, good spinnability essential for producing a spunbonded nonwoven fabric cannot be obtained, which is not suitable. The kneading method is a combination of "Laboplast Mill 50C150", "Segment Extruder" and "Cold Cut Pelletizer PETEC" manufactured by Toyo Seiki Seisaku-sho, Ltd., and kneading a mixture of bionole and carbon black by dry blending at a temperature of 150 ° C. And pelletized. The cooling was performed by air cooling.

The aliphatic polyester resin having thermoplasticity adjusted as described above is extruded from a spinneret of an extruder, and forms a group of long filaments drawn by high-speed high-pressure air from an ejector. Each of the long fibers is opened by frictional charging against the impact plate and repulsion by the charge. In this case, as a charging method, a corona discharge treatment may be performed on the long fiber to charge the long fiber. A large number of uniformly opened filaments are collected and deposited on a support such as a moving wire mesh belt to form a web.

The fineness of the long fiber is preferably in the range of 2.0 to 20 denier. If the fineness of the long fiber is less than 2.0 denier, the air permeability of the obtained nonwoven fabric becomes too low, the number of roots penetrating through the inner wall of the pot is reduced, and the growth may be insufficient. Conversely, when the fineness of the long fiber exceeds 20 denier, the air permeability of the obtained nonwoven fabric becomes too large, and almost all of the roots that reach the inner wall of the pot penetrate and become main roots, and the number of fine roots in the pot decreases. In addition, it is necessary to cut the main root at the time of planting, and it is not suitable because root survival may deteriorate.

In the present invention, self-fused areas of fibers are provided at regular intervals for the purpose of imparting sheet-like shape retention and strength to the web. 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 is preferably 5 to 50 ° C. lower than the melting point of the resin constituting the long fiber used. 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, if the difference between the roll temperature and the melting point of the resin exceeds 50 ° C., the formation of the self-fused portion becomes insufficient, and the strength of the spunbonded nonwoven fabric is remarkably reduced.

The linear pressure when the thermocompression treatment is performed with the uneven roll and the smooth roll is preferably 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. In any case, the strength of the spunbonded nonwoven fabric is reduced, so that it is not suitable.

As a method of forming the self-fused area, a web composed of a group of continuous continuous filament fibers is used.
It is also possible to form a point-fused portion corresponding to the projection by introducing it between the uneven roll and the ultrasonic horn and performing ultrasonic treatment.

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. On the other hand, if the area of the self-fused area exceeds 4 mm ² , the air permeability of the obtained nonwoven fabric becomes too small, and the number of roots penetrating through the inner wall of the pot decreases, and the growth becomes insufficient.

It is preferable that the total area of the self-fusing area is 2 to 30% of the total surface area of the long-fiber 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 air permeability of the obtained nonwoven fabric becomes too small, the number of roots penetrating through the inner wall of the pot becomes small, and the growth becomes insufficient.

The basis weight of the obtained biodegradable nonwoven fabric for seedling raising pot is in the range of 40 to 300 g / m ² . Weight is 40g
If it is less than / m ² , it is not suitable because the strength as a pot for raising seedlings is not sufficient. Conversely, if the basis weight is greater than 300 g / m ² , the resulting nonwoven fabric will have too low air permeability and will have less roots penetrating through the inner wall of the pot, resulting in insufficient growth and not suitable.

JIS L 1096 of the obtained nonwoven fabric
The air permeability measured with a Frazier-type tester (manufactured by Toyo Seiki Seisakusho) according to (Method A) is 0.5 to 100 cc / cm.
It is preferable to adjust within the range of ² / sec. When the air permeability is less than 0.5 cc / cm ² / sec, the number of roots penetrating through the inner wall of the pot is reduced, and as a result, even if the seedling is buried in the ground, the growth of the seedlings becomes insufficient. Conversely, if the air permeability exceeds 100 cc / cm ² / sec, almost all of the roots obtained on the inner wall of the pot penetrate and become main roots, and the number of fine roots in the pot decreases, so that the main root is cut off during planting. It is not suitable because it is necessary and roots take root worse.

As described above, the thermoplastic aliphatic polyester resin is heated and melted, extruded and spun from a number of die holes, and the spun continuous filament filaments are drawn from the ejector by high-speed high-pressure air to be supported. Collect on the body
In a nonwoven fabric which is deposited to form a web and the web is hot-embossed to provide partially and regularly heat-sealed areas, the thermoplastic aliphatic polyester comprises L-
A polylactic acid polymer containing 80 mol% or more of a lactic acid unit or a D-lactic acid unit, or a polybutylene succinate polymer synthesized from 1,4-butanediol and succinic acid was made to have a high molecular weight by a urethane bond. The biodegradable nonwoven fabric obtained by containing a polymer and containing carbon black having an average particle size of 0.1 to 2.0 μm in an amount of 0.5 to 20% by weight per resin weight has biodegradability. In addition, its speed can be controlled, and it can be suitably used for seedling pot applications.

[0037]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In Examples and Comparative Examples,% is% by weight unless otherwise specified.

Example 1 Melt flow rate was 20, melting point was 165 ° C.
A polylactic acid resin containing 98 mol% of lactic acid units (hereinafter referred to as A) was made to contain 18% by weight of carbon black having an average particle size of 1.7 μm per resin weight. Next, a continuous support made of a wire net is heated and melted at 220 ° C. in an extrusion melt spinning machine, and a continuous filament filament group spun from a die is drawn by an ejector while being stretched with high-speed high-pressure air, opened, and opened. It was collected and deposited on top to form a web. The fineness of this long fiber filament was 2.0 denier.

Further, the obtained web is introduced between a rough roll and a smooth roll heated to 135 ° C., and a portion corresponding to a convex portion of the rough roll is fused to obtain a basis weight of 292.
g / m ² of a spunbond nonwoven fabric was prepared. At this time, the linear pressure of the roll was 30 kg / cm, and the total area of the obtained fused areas was 4.0 area% based on the total surface area of the nonwoven fabric.

The obtained spunbonded nonwoven fabric was tested by the following test method, and its quality was evaluated. Test method (1) Air permeability: Measured according to JIS L 1096 (Method A). (2) Spinnability: Evaluated by the number of yarn breaks during melt spinning. The evaluation was based on the following five levels. 5: No thread breakage, and spinning properties are extremely good. 4: There is almost no yarn breakage, and the spinnability is good. 3: There is no problem with thread breakage, and the spinnability is normal. 2 ... Yarn breakage is considerable and spinnability is poor. 1 ... The yarn breakage is extremely large, and the spinnability is extremely poor.

(3) Tensile strength of spunbond nonwoven fabric:
The measurement was performed in accordance with JIS L 1906, and the measurement was performed in the longitudinal direction at a width of 50 mm of the spunbonded nonwoven fabric. (4) Decomposition speed: A nonwoven fabric cut to a size of 10 cm × 25 cm was put on cow manure compost-containing soil (weight composition ratio: cow manure compost 20%, soil 76%, peat moss 4%) and a depth of 15%.
buried 100 pieces in each cm, take out 2 pieces every 1 month and measure the weight.
The time (month) at which the weight% or more was obtained was measured, and the average value was calculated to be the decomposition rate. The observation was performed for 36 months.

Example 2 A non-woven fabric was produced in the same manner as in Example 1 except that a polybutylene succinate polymer synthesized from 4-butanediol and succinic acid was subjected to urethane polymerization (hereinafter referred to as B). The basis weight of the obtained nonwoven fabric was 289 g / m ² , and the fineness was 2.1 denier. Example 1
And the quality was evaluated.

Example 3 A nonwoven fabric was prepared in the same manner as in Example 1 except that the resin used was A, and the average particle size of carbon black containing A was 1.0 μm and the content was 0.7%. . The basis weight of the obtained nonwoven fabric was 250 g / m ² , and the fineness was 4.9 denier. The obtained nonwoven fabric was tested by the same test method as in Example 1, and its quality was evaluated.

Comparative Example 1 The resin used was A, and no carbon black was added to A. Other than that produced the nonwoven fabric like Example 1. The basis weight of the obtained nonwoven fabric was 290 g / m ² , and the fineness was 3.0 denier. The obtained nonwoven fabric was tested by the same test method as in Example 1, and its quality was evaluated.

Comparative Example 2 The resin used was B, and no carbon black was added to B. Other than that produced the nonwoven fabric similarly to the comparative example 1. The basis weight of the obtained nonwoven fabric was 287 g / m ² , and the fineness was 3.0 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 resin used was B, and the average particle diameter of the resin contained in B was 2.5 μm.
m and a nonwoven fabric were prepared in the same manner as in Example 1 except that the content was 10%. The basis weight of the obtained nonwoven fabric is 252.
g / m ² and fineness was 4.0 denier. The obtained nonwoven fabric was tested by the same test method as in Example 1, and its quality was evaluated.

Comparative Example 4 The resin used was B, and the average particle diameter of the resin contained in B was 1.0 μm.
m, and a nonwoven fabric were produced in the same manner as in Example 1 except that the content was 22%. The basis weight of the obtained nonwoven fabric is 280 g.
/ M ² and 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 5 The resins used were A, and the average particle diameter of the resin contained in A was 1.0 μm.
m and a nonwoven fabric were produced in the same manner as in Example 1 except that the content was changed to 0.3%. The basis weight of the obtained nonwoven fabric is 220
g / m ² and 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. Table 1 shows the results obtained in the examples and comparative examples.

[0049]

[Table 1]

As is clear from Table 1, the biodegradable nonwoven fabric for growing seedling pots obtained by the present invention has good spinnability, and the biodegradability can be changed by the content of carbon black (Examples). 1-3). On the other hand, when carbon black is not contained, the biodegradation rate is too high for seedling pot applications (Comparative Examples 1 and 2). When the average particle size of the carbon black is larger than the range or when the content of the carbon black is larger than the range, good spinnability cannot be obtained (Comparative Examples 3 and 4). When the content of carbon black is less than the specified range, the biodegradation rate is too fast to be used for seedling pots as in Comparative Examples 1 and 2 (Comparative Example 5).

[0051]

EFFECT OF THE INVENTION The present invention has biodegradability and can control its biodegradation rate arbitrarily.
An effect is provided of providing a biodegradable nonwoven fabric for a biodegradable seedling raising pot capable of maintaining strength for a required period.

Claims (3)

[Claims] 1. A thermoplastic aliphatic polyester resin is heated and melted, extruded and spun from a number of die holes, and a spun continuous filament filament group is drawn from an ejector by high-speed high-pressure air and captured on a support. In a nonwoven fabric comprising a web formed by collecting and accumulating a web and hot-embossing the web to form a heat-sealed area, the thermoplastic aliphatic polyester resin has an average particle size of 0.1 to 2. A biodegradable nonwoven fabric for raising seedling pots, comprising 0.5 to 20% by weight of carbon black of 0 μm per resin weight. 2. The thermoplastic aliphatic polyester resin,
The biodegradable nonwoven fabric for a nursery pot according to claim 1, comprising 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. 3. The thermoplastic aliphatic polyester resin,
The biodegradable nonwoven fabric for a nursery pot according to claim 1, comprising a polylactic acid polymer containing at least 80 mol% of an L-lactic acid unit or a D-lactic acid unit.