JPH09279446A - Biodegradable short fiber nonwoven fabric and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a nonwoven fabric comprising short fibers made of conjugate filament yarns of excellent cooling disposition. spinnability and drawability following their delivery from a spinneret, good in biodegradability which is controllable, and having enough excellent mechanical properties to stand its practical use. SOLUTION: First, a melt conjugate spinning is conducted to produce a sheath-core type conjugate fiber made up of core component consisting of a 1st biodegradable aliphatic polyester and sheath component consisting of a 2nd biodegradable aliphatic polyester lower in melting point than the 1st polyester. Subsequently, the conjugate fibers are drawn, the resultant oriented filament yarns are then mechanically crimped and cut to a specified length into short fibers, which are then carded into a short fiber web, which is, in turn, subjected to fluid jet treatment to effect three-dimensional interlacing of the constituent fibers into integration, thus affording the objective biodegradable short fiber nonwoven fabric.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a medical / hygiene material,
The present invention relates to a biodegradable short-fiber nonwoven fabric suitable for a wide range of applications where biodegradability is required, such as daily life materials and general industrial materials, and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Conventionally, as non-woven fabrics having biodegradability, for example, viscose short fiber non-woven fabrics obtained by a dry method or a solution dipping method, cupra rayon long fiber non-woven fabrics and viscose rayon long fiber non-woven fabrics obtained by a wet method. Nonwoven fabrics made of natural chemical fibers such as chitin and collagen, spunlace nonwoven fabric made of cotton, and the like are known. However, since these biodegradable nonwoven fabrics have low mechanical strength and are hydrophilic, the mechanical strength upon water absorption / wetting is significantly reduced. Further, since these non-woven fabrics are non-thermoplastic in nature, they have problems such as lack of thermal adhesiveness and thermoformability.

As a biodegradable non-woven fabric which solves such a problem, there is disclosed in Japanese Patent Laid-Open No. 93318/1993 or Japanese Patent Laid-Open No. 5-93318.
Japanese Patent No. 195407 discloses a non-woven fabric using a biodegradable thermoplastic polymer. But these are
The spun yarn during production was inferior in the cooling property, spinnability, and stretchability, and, since it was a fully melted type in the hot pressing process, the resulting nonwoven fabric was inferior in mechanical properties and flexibility. .

Such problems occur in the process of producing a biodegradable nonwoven fabric because the melting point and crystallization temperature of a biodegradable polymer are generally low and the crystallization rate is slow. That is, adhesion between yarns occurs during cooling / thinning after melt spinning, and operability is significantly impaired in the drawing / crimping step in the next step.
Moreover, in the conventional manufacturing method as described above, control of biodegradation performance is possible to some extent by changing the type of polymer to be applied, fineness, orientation degree of fiber, etc., but delicate control is possible. Was impossible.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above problems, has excellent cooling properties, spinnability and stretchability of spun yarns, has good biodegradability, and is controllable. In addition, the present invention aims to provide a biodegradable short fiber nonwoven fabric having further excellent mechanical properties and a method for producing the same.

[0006]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above problems, and as a result, have reached the present invention. That is, the present invention has the following structures.

(1) A staple fiber web composed of composite staple fibers is integrated by three-dimensional entanglement, and the composite staple fiber comprises a core component composed of a first aliphatic polyester having biodegradability and the core component. A biodegradable short-fiber nonwoven fabric having a core-sheath type composite cross section formed from a sheath component made of a second aliphatic polyester having a low melting point and having biodegradability.

(2) Using a core component made of a first aliphatic polyester having biodegradability and a sheath component made of a second aliphatic polyester having a lower melting point than that of the core component, The core-sheath type composite fiber is melt-combined and then drawn, and the resulting drawn yarn is mechanically crimped and then cut into a predetermined length to form a short fiber. A method for producing a biodegradable short fiber non-woven fabric, which comprises forming a fiber web and subjecting the short fiber web to a pressurized liquid flow treatment to three-dimensionally entangle and integrate the constituent fibers.

As described above, the biodegradable short fiber nonwoven fabric of the present invention is formed by the core-sheath type composite short fibers which are composed of two components which are biodegradable and have different melting points. It has excellent coolability, spinnability, stretchability, and biodegradability of the spinning yarn, and has controllable biodegradability.

Furthermore, since the biodegradable short fiber nonwoven fabric of the present invention is integrated by three-dimensional entanglement, it has excellent mechanical properties and texture.

[0011]

First, the short fiber web of the present invention will be described. The staple fiber applied in the present invention includes a core component made of the first aliphatic polyester having biodegradability and a second biodegradability having a melting point lower than that of the core component.
Is a composite short fiber formed from a sheath component composed of the aliphatic polyester of.

First and second constituents of the core and sheath components
Examples of the biodegradable aliphatic polyester include poly (α-hydroxy acid) such as polyglycolic acid and polylactic acid, or a copolymer of repeating unit elements constituting them. In addition, poly (ω-caprolactone), poly (ω-propionate such as poly (β-propiolactone),
-Hydroxyalkanoate) and poly-3-
Hydroxypropionate, poly-3-hydroxybutyrate, poly-3-hydroxycaproate, poly-3
-Poly (β-hydroxyalkanoate) such as hydroxyheptanoate and poly-3-hydroxyoctanoate, and repeating unit elements and poly-constituting them
Examples thereof include copolymers with repeating unit elements constituting 3-hydroxyvalerate and poly-4-hydroxybutyrate. In addition, as a polycondensate of diol and dicarboxylic acid, for example, polyethylene oxalate,
Polyethylene succinate, polyethylene adipate,
Polyethylene azetate, polybutylene oxalate,
Polybutylene succinate, polybutylene adipate,
Examples thereof include polybutylene sebacate, polyhexamethylene sebacate, polyneopentyl oxalate, and copolymers of repeating unit elements constituting these. Further, a plurality of the above aliphatic polyesters may be blended and used. Among the above-mentioned aliphatic polyesters, polybutylene succinate, polyethylene succinate and polybutylene adipate are particularly preferable from the viewpoint of spinnability and biodegradability, and more particularly, butylene succinate as a main repeating unit and ethylene succinate. A copolyester obtained by copolymerizing nate or butylene adipate is preferable. In the present invention, of the two polymers selected from the above aliphatic polyesters, the polymer with the higher melting point is placed in the core,
The polymer with the lower melting point is placed in the sheath.

Incidentally, the aliphatic polyester is generally
The higher the melting point, the better the cooling properties, spinnability and stretchability of the spun yarn, but the poorer the biodegradability due to the higher crystallinity. Conversely, the lower the melting point, the higher the melting point of the spun yarn. Although it is inferior in cooling property, spinnability and stretchability, it has excellent biodegradability due to its low crystallinity. For example, when the fiber cross section is composed of a component single phase having a relatively high melting point, the target biodegradability cannot be obtained, although the spinnability and the non-woven fabric are excellent. On the other hand, when the cross-section of the fiber is composed of a single component phase having a relatively low melting point, the meltability of the spun yarn is inferior in the cooling property during melt spinning, and a nonwoven fabric cannot be obtained.

In the present invention, for example, even if the sheath component is a polymer having inferior cooling properties and drawability, by using a polymer having a relatively high melting point as the core component, the cooling properties of the spun yarn, The stretchability can be improved. Further, even if the core component is a polymer having poor biodegradability, by compositing a polymer having a relatively low melting point and excellent biodegradability, the core component will be left behind in the state of fineness over time. The result is excellent biodegradability as a nonwoven fabric.

From this, polybutylene succinate is used as the core component, and ethylene succinate or butylene adipate is added to butylene succinate so that the copolymerization ratio of butylene succinate is 70 to 90 mol% as the sheath component. It is preferable to use a copolyester obtained by copolymerizing the above. When the copolymerization amount ratio of butylene succinate is less than 70 mol%, the biodegradability is excellent, but the cooling property, spinnability and stretchability of the spun yarn are poor, and the target short fibers can be obtained. There will be no. vice versa,
If it exceeds 90 mol%, the cooling and spinnability of the spun yarn,
Although it is excellent in stretchability, it is inferior in biodegradability and is not the object of the present invention.

In the present invention, the above-mentioned aliphatic polyester applied to the core component and the sheath component has a number average molecular weight of about 20,000 or more, preferably 40,000 or more, more preferably 60,000 or more. However, they are good in terms of spinnability and characteristics of the obtained yarn. Further, it may be chain-extended with a small amount of diisocyanate or tetracarboxylic dianhydride in order to increase the degree of polymerization.

In the present invention, either or both of the core component and the sheath component described above may be added, if necessary.
For example, matting agents, pigments, light stabilizers, antioxidants and the like can be added within a range that does not impair the effects of the present invention.

Particularly, in the present invention, it is preferable that a crystal nucleating agent is added to at least the sheath component among the constituent components in order to improve the cooling property of the spun yarn in the production of short fibers. . Addition of a nucleating agent can prevent adhesion between spun yarns even for a low-crystalline polymer that is hard to solidify after melt spinning. Here, the crystal nucleating agent is a powdered inorganic substance, and is not particularly limited unless it dissolves in the melt, but talc, calcium carbonate, titanium oxide, boron nitride, silica gel, magnesium oxide or A mixture of these is preferably used.

When the crystal nucleating agent is added, the amount of the crystal nucleating agent added to the core component is QA (% by weight), and the amount of the crystal nucleating agent added to the sheath component is QB (% by weight). It is preferable that it is added so as to satisfy the expressions (1) and (2). [(ΔTA + ΔTB) / 100] −2 / 3 ≦ QA + QB ≦ [(ΔTA + ΔTB) / 100] +4 (1) QA ≦ QB (2) where ΔTA = melting point of core component−crystallization of core component Temperature ΔTB = melting point of sheath component−crystallization temperature of sheath component When the total amount of crystal nucleating agent QA + QB (% by weight) exceeds the upper limit defined by the formula (1), the effect of cooling the spun yarn is high. However, this is not preferable because the spinnability is deteriorated and the mechanical properties of the obtained short fibers and thus the nonwoven fabric are poor. On the contrary, if the total amount of the crystal nucleating agent QA + QB (% by weight) becomes lower than the lower limit defined by the equation (1), the cooling property of the spun yarn is deteriorated and adhesion occurs between the spun yarns. However, it becomes difficult to obtain the target short fiber. When the amount QA (wt%) of the crystal nucleating agent added to the core component is larger than the amount QB (wt%) of the crystal nucleating agent added to the sheath component, the cooling property of the core component is further improved. However, the cooling property of the sheath component is lowered, and this tends to cause adhesion between spun yarns, which is not preferable.

In the present invention, the viscosities of the core component and the sheath component are not particularly limited, but the viscosity of the core component is preferably higher than that of the sheath component. This is because the low-viscosity component generally acts in the composite spinning of the thermoplastic resin so as to cover the high-viscosity component. That is, in the present invention, by making the core component highly viscous, it becomes suitable for maintaining the core-sheath form in the cross section of the fiber.

Therefore, the melt flow rate value (hereinafter referred to as MFR value) of the polymer applied in the present invention is 5 to 50 g / 10 minutes for the core component and 10 to 70 g / 1 for the sheath component.
It is preferably 0 minutes. However, the MF in the present invention
The R value is measured according to the method described in ASTM-D-1238 (E). MFR value of core component is 5g / 1
Less than 0 minutes and / or MFR value of sheath component is 10 g / 10
If the amount is less than the minute, the viscosity is too high, and the spun yarn cannot be thinned smoothly, resulting in impaired operability, and the obtained fiber has a large fineness and poor uniformity. Conversely, the MFR value of the core component is 50 g / 10 minutes and /
Or, when the MFR value of the sheath component exceeds 70 g / 10 minutes,
Since the viscosity is too low, not only the composite cross section becomes unstable, but also yarn breakage occurs in the spinning process, impairing operability, and the resulting nonwoven fabric has poor mechanical properties. For these reasons, the MFR value of the core component is 10
~ 45g / 10min, MFR value of sheath component is 15 ~ 65g /
More preferably, it is 10 minutes.

The composite short fibers applied to the present invention preferably have a core component / sheath component composite ratio of 1/3 to 3/1 (weight ratio). If the composite ratio is out of this range, the spinnability of the spun yarn cannot be satisfied together with the cooling property, spinnability, stretchability and biodegradability, and further, instability of the fiber cross-sectional shape is induced. Therefore, it is not preferable. For example, when the composite ratio of the core component / the sheath component exceeds 1/3, the biodegradability is excellent, but the cooling property, spinnability and stretchability of the spun yarn are poor. On the other hand, when the composite ratio of the core component / the sheath component exceeds 3/1, the spun yarn has excellent cooling properties, spinnability and stretchability, but poor biodegradability. Further, for example, when the core component is a polymer having poor biodegradability, the biodegradation rate can be accelerated by increasing the composite ratio of the sheath component. For this reason, more preferably 1 /
2.5-2.5 / 1 (weight ratio) is good.

In the present invention, the single yarn fineness of the composite short fibers is preferably 1.5 to 10 denier. 1.5
When it is less than denier, the spinneret becomes complicated, the number of yarn breakages in the spinning process increases, the production amount decreases, and the fiber cross-sectional shape becomes unstable. On the other hand, when it exceeds 10 denier, the spun yarn has poor cooling properties and biodegradability. For this reason, 2 to 8 denier is more preferable.

As described above, the short fiber nonwoven fabric of the present invention is
A web formed of a core-sheath type composite short fiber composed of a core component and a sheath component made of biodegradable aliphatic polyester having different melting points, and combining the composite ratio of both components, single yarn fineness, etc. As a result, the required cooling property, spinnability and stretchability of the spun yarn can be obtained, and the biodegradability can be controlled.

The biodegradable short fiber nonwoven fabric of the present invention is a short fiber web composed of the above-mentioned composite short fibers integrated by three-dimensional entanglement. That is, the constituent fibers of the short fiber web are three-dimensionally entangled and integrated with each other by performing the pressurized liquid flow treatment described later. As a result, the short-fiber nonwoven fabric of the present invention is strong enough to withstand practical use, can be integrated, and can exhibit excellent mechanical properties.

Next, a method for producing the biodegradable short fiber nonwoven fabric of the present invention will be described. First, the production of the short fiber web applied to the present invention can be carried out using an ordinary composite spinning apparatus and drawing apparatus. That is, the core component and the sheath component made of the above-mentioned biodegradable polymer are melted and individually weighed, and this is mixed at the above-mentioned composite ratio through a composite spinneret capable of forming a core-sheath composite cross section. And the spun yarn is cooled by a known cooling device using a cooling air flow or the like.
Then, the undrawn yarn is wound up by a take-up roll at a speed of 800 to 2500 m / min, and the undrawn yarn is drawn at a predetermined draw ratio between drawing rolls having different peripheral speeds. here,
The number of drawing rolls and the drawing temperature in the drawing step may be appropriately selected. For example, in the case of stretching the fineness, it is necessary to increase the number of stretching rolls and further perform hot stretching. Then, the obtained drawn yarn is crimped with a stuffer box and then cut into a predetermined length to obtain short fibers. Although the above-described method is a two-step method, short fibers can also be obtained by a one-step method, that is, a so-called spin draw method in which undrawn yarn is continuously drawn without being wound up.

Further, in the present invention, as described above,
It is preferable to add a nucleating agent to the polymer used. Thereby, the cooling property of the spun yarn during the melt spinning can be improved. The crystal nucleating agent is added in the polymerization step or the melting step. At this time, it is preferable to disperse the nucleating agent as uniformly as possible in order to improve the mechanical performance and the uniformity of the obtained yarn.

Then, the obtained short fibers are carded by a known card machine to prepare a short fiber web having a predetermined weight. Then, the obtained short fiber web is subjected to a pressurized liquid flow treatment to form a three-dimensional entanglement between the constituent fibers to integrate them, thereby obtaining a biodegradable short fiber nonwoven fabric.

The short fiber web in the present invention is either a parallel web arranged in the traveling direction of the card machine, a crosslaid web of parallel webs, a randomly arranged random web or a semi-random web arranged in the middle. It may be selected according to the intended use. Especially when used for clothing,
In terms of strength as a non-woven fabric, the longitudinal / lateral strength ratio is approximately 1 /
It is preferable to use a card web of 1.

When performing the pressurized liquid flow treatment, as the injection holes for the pressurized liquid flow, orifices having a diameter of 0.05 to 1.5 mm are arranged in one row or a plurality of rows at 0.4 to 5 mm intervals. It is preferable to use a head and arrange the orifice heads in 3 to 10 stages. The orifice head may be arranged on one side or both sides of the short fiber web.

In the pressurized liquid flow process, the first liquid pressure is set to 45.
After pre-entanglement with a pressurized liquid flow of less than kg / cm ² G, then 45 kg / cm as the second and subsequent treatments.
^It is performed by performing an entanglement treatment with a pressurized liquid flow having a hydraulic pressure of ² G or more. When the first hydraulic pressure is 45 kg / cm ² G or more, the turbulence of the web occurs due to the accompanying airflow generated by the pressurized liquid flow, and the short fibers constituting the web are generated by the pressurized liquid flow. It is not preferable in terms of maintaining the quality of the biodegradable short-fiber non-woven fabric which is dropped and becomes a product. The biodegradable short fiber non-woven fabric obtained by the above method is inverted, and the front and back are integrated by subjecting the third confounding treatment to the confounding treatment by the hydraulic pressure applied to the second time. Can be obtained.

In the treatment of the pressurized liquid flow, the porous support plate on which the short fiber web is placed is made of metal as long as the pressurized liquid flow passes through the short fiber web placed on the support plate. Any of polyester and other materials may be used. The range of the mesh of the porous support plate is appropriately selected depending on the application, but it is preferable to use the mesh of 20 to 150 mesh. When it is less than 20 mesh, the resulting biodegradable short fiber nonwoven fabric is substantially perforated, and for example,
When used for purposes such as household and commercial waste,
Fine scraps flow out from this hole portion, which is not preferable. On the other hand, if it exceeds 150 mesh, it is necessary to increase the liquid pressure of the liquid flow passing through the short fiber web and the net, which is not preferable in terms of production cost. For the above reasons, the range of the mesh of the porous support plate is more preferably 30 to 100 mesh.

The biodegradable short-fiber non-woven fabric obtained by the above method is subjected to a drying treatment after removing excess water with a known water removing device such as mangle. The basis weight of the biodegradable short fiber non-woven fabric of the present invention is not particularly limited because it is selected according to the purpose of use, but it is generally preferably in the range of 10 to 150 g / m ² , and more preferably 15 to 70 g. It is better to set it in the range of / m ² . When the basis weight is less than 10 g / m ² , flexibility and biodegradation rate are excellent, but mechanical strength is poor and it is not practical. On the other hand, when the basis weight exceeds 150 g / m ² , the nonwoven fabric has a hard texture and is inferior in flexibility.

[0034]

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

In the examples, each physical property value was measured by the following methods.

Melt flow rate value (g / 10 minutes);
The temperature was measured at 190 ° C. according to the method described in ASTM-D-1238 (E). (Hereinafter referred to as MFR value)

Melting point (° C.); maximum value of melting endotherm curve obtained by measurement using a differential scanning calorimeter DSC-2 type manufactured by Perkin Elma Co., Ltd. with a sample weight of 5 mg and a heating rate of 20 ° C./min. Was given as the melting point (° C.).

Crystallization temperature (° C.); using a differential scanning calorimeter DSC-2 type manufactured by Perkin Elma Co., and a sample weight of 5 m
g, the temperature giving the maximum value of the solidification exothermic curve obtained by measuring the cooling rate at 20 ° C./min was defined as the crystallization temperature (° C.).

Coolability: The spun yarn was visually observed and evaluated according to the following three grades. ◯: No adhesion thread is observed. Δ: A small amount of adhesive thread is recognized. X: Most of them are in close contact.

Spinnability: Good; no yarn breakage occurs, and spinning operability is good. X: Thread breakage occurs frequently and spinning operability is poor.

Stretchability: Good: Stretching fluff is not generated and stretching operability is good. X: Stretching fuzz occurs frequently and stretching is impossible.

-Unit weight (g / m ² ); 10 pieces of a sample having a sample length of 10 cm and a sample width of 10 cm were prepared from a sample in a standard state, equilibrated with water, and then the weight (g) of each sample piece was measured. Then, convert the average value of the obtained values per unit area,
The basis weight (g / m ² ) was used.

Strength of non-woven fabric (kg / 5 cm width); JI
It was measured according to the method described in S-L-1096A. That is, a sample piece 1 having a sample length of 20 cm and a sample width of 5 cm
A zero point was created, and a tensile speed of 1 was set for each sample piece in the longitudinal direction of the nonwoven fabric using a constant-speed extension-type tensile tester (Tensilon UTM-4-1-100 manufactured by Toyo Baldwin Co., Ltd.).
It was stretched at 0 cm / min, and the average value of the load values at cutting obtained was taken as the strength (kg / 5 cm width).

・ Biodegradability: 6 is obtained by embedding a non-woven fabric in soil.
If the nonwoven fabric does not retain its shape after a month, or if the strength is reduced to 50% or less of the initial strength value before embedding even if it retains its shape, the biodegradation performance is The biodegradability was evaluated as poor (; x) if the strength was more than 50% of the initial strength before embedding.

Example 1 A core component having an MFR value of 20 g / 10 minutes and a melting point of 114
Polybutylene succinate having a crystallization temperature of 75 ° C.
As a sheath component, MFR value is 30g / 10min and melting point is 102
Using a copolymer of butylene succinate / ethylene succinate = 85/15 mol% at a crystallization temperature of 52 ° C. and a crystallization temperature of 52 ° C., a short fiber web composed of core-sheath type composite short fibers was produced. That is, the core component and the sheath component were melted at a temperature of 180 ° C. using separate extruder type melt extruders, and a spinneret having a core-sheath composite cross section was used, and single hole discharge rate = 1.02 g / min. , Composite ratio (core component / sheath component) = 1/1
Melt spinning was performed under the condition of (weight ratio). After cooling this spun yarn with a cooling device, an oil agent is applied, and the speed is 800
An undrawn yarn having a fineness of 11.5 denier was obtained through a take-up roll of m / min. A plurality of the obtained unstretched yarn bundles were bundled, stretched at a stretching ratio of 4.0 times under the condition that the stretching temperature was room temperature, and then crimped with a stuffer box at 15 pieces / inch, and then 51 mm. Cut, brand 3d x 5
1 mm short fibers were obtained. This short fiber was supplied to a parallel card machine to prepare a card web having a basis weight of 50 g / m ² .

Then, the obtained short fiber web is placed on a moving 40-mesh wire mesh, and the upper part of the short fiber web is placed 5
From the position of 0 mm, a hole diameter of 0.
A biodegradable short product with a unit weight of 50 g / m ^{2 which} is three-dimensionally entangled by performing pressurized liquid flow treatment using a device in which orifice heads arranged in a row with 12 mm and hole spacing of 0.6 mm are arranged in 5 stages. A fibrous nonwoven fabric was obtained. As the treatment condition, after the first hydraulic pressure was set to 35 kg / cm ² G for pre-entanglement, the second and subsequent hydraulic pressures were set to 90 kg / cm ² G to form three-dimensional entanglement between the constituent fibers. Then, after removing excess water of the obtained non-woven fabric by mangle, a drying treatment was performed by a drier kept at a temperature of 80 ° C. Table 1 shows the operability and biodegradability of the short-fiber nonwoven fabric and the biodegradability of the core-sheath type composite short fiber production.

Example 2 Melt spinning was performed at a single hole discharge rate of 0.40 g / min and a composite ratio (core component / sheath component) = 1/3 (weight ratio), and a single yarn fineness of 4.6 denier was measured. A core-sheath type composite short fiber was produced under the same conditions as in Example 1 except that a drawn yarn was obtained, drawn at a draw ratio of 3.2 and cut into 38 mm. The obtained short fibers had a brand of 1.5 d × 38 mm. This short fiber is fed to a parallel card machine and the basis weight is 50 g /
Create a card web m ^2, subjected to pressurized liquid jet treatment under the same conditions as in Example 1 to obtain a biodegradable staple fiber nonwoven fabric obtained by three-dimensional entanglement. Table 1 shows the operability and biodegradability of the short-fiber nonwoven fabric and the biodegradability of the core-sheath type composite short fiber production.

Example 3 Single-hole discharge amount = 4.10 g / min, melt-spinning was performed at a composite ratio (core component / sheath component) = 3/1 (weight ratio), and an undrawn yarn having a single yarn fineness of 46 denier Example 1 except that the above was obtained and stretched at a stretch ratio of 4.8 times and cut into 76 mm.
Under the same conditions as above, a core-sheath type composite staple fiber was produced. The obtained short fibers had a brand of 10 d × 76 mm. This short fiber is fed to a parallel card machine and the basis weight is 50 g / m ²
The card web of No. 2 was prepared and subjected to a pressurized liquid flow treatment under the same conditions as in Example 1 to obtain a three-dimensionally entangled biodegradable short fiber nonwoven fabric. Table 1 shows the operability and biodegradability of the short-fiber nonwoven fabric and the biodegradability of the core-sheath type composite short fiber production.

Example 4 A short fiber non-woven fabric composed of core-sheath type composite short fibers was produced in the same manner as in Example 1 except that a crystal nucleating agent was added to the high melting point component and the low melting point component. That is, as a crystal nucleating agent, talc / titanium oxide having an average particle size of 1.0 μm = 1 /
A master batch containing 20% by weight of 1 (weight ratio) was prepared in advance based on a high-melting-point component polymer and a low-melting-point component polymer, and the master batch and the corresponding polymer were each blended to obtain a high melting point. The crystal nucleating agent added to the components was 0.2% by weight, and the crystal nucleating agent added to the low melting point component was 1.0% by weight to prepare raw materials. Table 1 shows the operability and biodegradability of the short-fiber nonwoven fabric and the biodegradability of the core-sheath type composite short fiber production.

Comparative Example 1 The same core component as in Example 1 was used, and the single hole discharge rate was 0.97 g / through a spinneret having a fiber cross section of a single phase type cross section.
Melt-spun under the conditions of minutes. That is, the core component was heated at a temperature of 180 ° C. using an extruder type melt extruder.
Melted and melt-spun through a spinneret having a single-phase cross-section, the spun yarn is cooled in a cooling device, and then an oil agent is applied. The speed is 800 m / min and the fineness is obtained through a take-up roll. To obtain 10.9 denier undrawn yarn. A plurality of the obtained unstretched yarn bundles are bundled, stretched at a stretching ratio of 3.8 under a stretching temperature of room temperature, then crimped with a stuffer box at 14 pieces / inch, and then cut into 51 mm. Then, a short fiber of brand 3d × 51 mm was obtained. This short fiber was fed to a parallel card machine to prepare a card web having a basis weight of 25 g / m ² , and a pressurized liquid flow treatment was carried out under the same conditions as in Example 1, and three-dimensionally entangled biodegradable short fibers. A fibrous nonwoven fabric was obtained. Table 1 shows the operability and biodegradability of the short-fiber nonwoven fabric and the biodegradability of the core-sheath type composite short fiber production.

Comparative Example 2 The same sheath component as in Example 1 was used, and a single hole discharge rate = 0.97 g / through a spinneret having a fiber cross section of a single phase type cross section.
Was melt-spun under the condition of min., The spun yarn was cooled by a cooling device, and then an oil agent was applied to obtain undrawn yarn through a take-up roll having a speed of 800 m / min. Since the undrawn yarn was adhered between the yarns, a single-phase spun yarn could not be obtained.

[0052]

[Table 1]

As is clear from Table 1, since the nonwoven fabric obtained in Example 1 uses the core-sheath type composite staple fiber of the present invention, the spun yarn has cooling properties, spinnability and drawing properties. It was also excellent in mechanical properties and mechanical properties. Further, when this non-woven fabric was embedded in soil for 6 months and then excavated and observed, it was confirmed that the non-woven fabric did not retain its form and had good biodegradability.

In Example 2, although the ratio of the sheath component was large, the fineness was small and the core-sheath type composite staple fiber was applied. Spinnability,
The stretchability was also good, and this nonwoven fabric was also excellent in mechanical properties. Further, the biodegradability was higher than that of the nonwoven fabric obtained in Example 1 because the ratio of the sheath component was large.

In Example 3, since the ratio of the core component was large and the core-sheath type composite short fibers were applied, the spinning yarn was cooled in the same manner as in Example 1 even though the fineness was large. The spinnability, spinnability and stretchability were also good. Further, this non-woven fabric was also excellent in mechanical properties and biodegradability.

In Example 4, since the crystal nucleating agent was contained in the polymer, the spinnability of the spun yarn was better than that of Example 1. Further, this non-woven fabric was also excellent in mechanical properties and biodegradability.

On the other hand, in Comparative Example 1, although the same core component as in Example 1 was used, the cross-section of the fiber was a single-phase type which was outside the scope of the present invention, so the mechanical properties of the nonwoven fabric were Although excellent, the non-woven fabric was buried in the soil for 6 months, and then excavated and observed, the non-woven fabric form was maintained, and the non-woven fabric strength was 91% before embedding, which is significantly inferior in biodegradability. It was

In Comparative Example 2, although the same sheath component as in Example 1 was used, the single-phase spun yarn could not be obtained because the undrawn yarn was in close contact between the yarns.

[0059]

EFFECTS OF THE INVENTION According to the present invention, the spun yarn has excellent cooling properties, spinnability and stretchability, has good biodegradability, and can be controlled, and can withstand practical use. It is possible to provide a biodegradable short fiber non-woven fabric having sufficient mechanical properties and a method for producing the same.

The biodegradable short fiber non-woven fabric of the present invention is used for diapers, sanitary products and other medical and hygiene materials, wipes such as disposable hand towels and wiping cloths, disposable packaging materials, and household / commercial garbage collection. It is suitable as a material for daily life such as bags and other waste treatment materials, or an industrial material typified by agriculture, horticulture and civil engineering.
Moreover, since this biodegradable short-fiber non-woven fabric has biodegradability, it is completely decomposed and lost after its use, which is beneficial from the viewpoint of protecting the natural environment, or reused, for example, by composting it into fertilizer. It is also useful from the viewpoint of resource reuse because it can be achieved.

Claims (6)

[Claims] 1. A staple fiber web composed of composite staple fibers is integrated by three-dimensional entanglement, and the composite staple fiber comprises a core component composed of a first aliphatic polyester having biodegradability and a core component composed of the core component. A biodegradable short-fiber non-woven fabric having a core-sheath composite cross section formed from a sheath component made of a second aliphatic polyester having a low melting point and having biodegradability. 2. The core component is polybutylene succinate, and the sheath component is copolymerized with ethylene succinate or butylene adipate in butylene succinate so that the copolymerization amount ratio of butylene succinate is 70 to 90 mol%. The biodegradable short fiber non-woven fabric according to claim 1, which is a copolymerized polyester that is polymerized. 3. The biodegradable short fiber non-woven fabric according to claim 1, wherein a crystal nucleating agent is added to at least the low melting point component of the low melting point component and the high melting point component. 4. A single yarn fineness composed of a core component and a sheath component is 1.5 to 10 denier, and a composite ratio of the core component / the sheath component is 1/3 to 3/1 (weight ratio). The biodegradable short-fiber non-woven fabric according to any one of claims 1 to 3, characterized in that. 5. A core comprising a core component made of a first aliphatic polyester having biodegradability and a sheath component made of a second aliphatic polyester having a lower melting point than that of the core component. Melt composite spinning of sheath-type composite fibers is followed by drawing, and the resulting drawn yarn is mechanically crimped and then cut into predetermined lengths to form short fibers, and the short fibers are carded to obtain short fibers. A method for producing a biodegradable short fiber nonwoven fabric, which comprises forming a web and subjecting the short fiber web to a pressurized liquid flow treatment to three-dimensionally entangle and integrate the constituent fibers. 6. The biodegradable short fiber non-woven fabric according to claim 5, wherein a crystal nucleating agent is added to at least the low melting point component of the low melting point component and the high melting point component to carry out melt composite spinning. Manufacturing method.