JP2000248452A - Antimicrobial nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject nonwoven fabric excellent in flexibility, hygroscopicity/water absorptivity and bacteriostatic/antimicrobial effect by imparting a hydrophilic surfactant to a nonwoven fabric comprising polylactic acid-based fibers and another kind of fibers with the official moisture regain at a specific level or higher. SOLUTION: This antimicrobial nonwoven fabric >=2.2 in bacteriostatic activity number is obtained by imparting >=100 ppm of a hydrophilic surfactant to a nonwoven fabric made by blending 30-70 wt.% of fibers >=5% in the official moisture regain (e.g. cotton) in polylactic acid-based fibers >=80 deg.C in melting point made from a polymer selected from the group consisting of poly(D-lactic acid), poly(L-lactic acid), D-lactic acid/L-lactic acid copolymers, D-lactic acid/ hydroxycarboxylic acid copolymers, L-lactic acid/hydroxycarboxylic acid copolymers, and DL-lactic acid/hydroxycarboxylic acid copolymers, and blends thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonwoven fabric having high flexibility and antibacterial properties and a method for producing the same.

[0002]

2. Description of the Related Art A method of imparting antibacterial properties to a material has hitherto been used today. For example, there is a method in which a fiber material, a fiber cloth, a sheet or the like is subjected to a surface treatment with an antibacterial substance. However, although this method can impart antibacterial performance, there is a problem that the durability of the antibacterial performance is poor. As a method for solving this problem, there is a method of mixing and kneading an active antibacterial substance in a manufacturing process of a fiber material such as nylon or polyester. However, although this method shows a certain antibacterial performance, it is costly. In general, many antibacterial agents themselves have a certain degree of toxicity, which poses a safety problem.

[0003]

DISCLOSURE OF THE INVENTION In view of the above problems, the present inventors have studied a safe and low-cost antibacterial agent. Hitherto, lactic acid has been used as a food preservative to improve the shelf life of food.
It is known to have a fungicidal action. However, there has been no clear report that fibers and films made of polylactic acid polymer, which is a dehydration-condensation polymer of lactic acid, have antibacterial properties.Moreover, antimicrobial properties were discussed in relation to polylactic acid polymer composition. There is no report. The present inventors have conducted various studies on the relationship between polylactic acid polymer and antibacterial properties in order to express the latent bacteriostatic and fungicidal action of lactic acid in the process of forming and processing fibers, and as a result, polylactic acid polymer was obtained. The present inventors have found that a remarkable antibacterial activity is observed in a specific composition range of the constituent components of the combination, and have reached the present invention.

[0004]

The present invention comprises a polylactic acid-based fiber and a fiber having an official moisture content of 5% or more, a nonwoven fabric provided with a hydrophilic surfactant, and a bacteriostatic activity value of 2%. .2
The gist of the present invention is an antibacterial nonwoven fabric characterized by the above.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The polylactic acid-based polymer constituting the polylactic acid-based fiber used in the present invention is a thermoplastic aliphatic polyester, and a polymer having poly (α-hydroxy acid) as a main repeating unit is used. No. Specifically, poly (D-lactic acid), poly (L-lactic acid), a copolymer of D-lactic acid and L-lactic acid, a copolymer of D-lactic acid and hydroxycarboxylic acid, and a copolymer of L-lactic acid and hydroxycarboxylic acid Copolymers with carboxylic acids, DL-lactic acid and hydroxycarboxylic acids, and the like,
Among these polymers, those having a melting point of 80 ° C. or higher are preferred. Here, examples of the hydroxycarboxylic acid in the case of a copolymer of lactic acid and hydroxycarboxylic acid include glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxyheptanoic acid, hydroxycaprylic acid, and the like.

[0006] Such a polylactic acid-based polymer has a number average molecular weight of about 20,000 or more, preferably 40,000 or more, in view of the spinning properties and the obtained yarn properties. As for the upper limit of the number average molecular weight, it is sufficient that melt spinning can be performed, and it is sufficient that the number average molecular weight be about 150,000.

[0007] If necessary, other additives such as matting agents, pigments, nucleating agents and the like may be added to the polylactic acid-based polymer within a range that does not impair the effects of the present invention. good.

[0008] The cross-sectional shape of the polylactic acid-based fiber may be any shape such as an elliptical shape, a diamond shape, a triangular shape, a rectangular shape, a polygonal shape, a T-shaped shape, a well-shaped shape, etc., in addition to a normal round shape. Can be selected as appropriate. Further, it may have a hollow cross-sectional shape having a hollow portion.

The polylactic acid-based fibers may be of a single-phase form composed of one kind of polylactic acid-based polymer alone or of a composite form composed of two or more kinds of polylactic acid-based polymers. Examples of the composite form include a parallel composite form, a multilayer composite form, a core-in-sheath composite form, a split composite form, and a split multilobal composite form, and may be appropriately selected according to the use and the like.

[0010] In the polylactic acid-based fiber constituting the nonwoven fabric of the present invention, the larger the fiber surface area, the larger the contact area with the bacterium, so that a more bacteriostatic action can be exerted. When the fiber is used for applications requiring high surface area, a fiber having a large surface area is excellent in decomposability. Therefore, it is preferable to use a fiber having a cross-sectional shape such as a hollow cross section, a modified cross section, or a split composite cross section.

The degree of crystallinity of the polylactic acid fiber is 10 to 40.
%. By setting the crystallinity of the fiber within the above range, the heat shrinkage of the fiber is suppressed to be low, and the fiber has practical mechanical strength. Crystallinity in the above range, by performing a heat treatment or stretching, and, for the polylactic acid-based polymer, for example, talc, boron nitride, calcium carbonate, magnesium carbonate, a crystal nucleating agent such as titanium oxide This is achieved by adding. The addition of a crystal nucleating agent promotes fiber crystallization, improves the mechanical strength and heat resistance of the resulting nonwoven fabric, and also melts the spun yarn in the melt spinning and cooling steps during production. This is preferable in that it is possible to prevent wearing (blocking). The amount of the nucleating agent added is in the range of 0.1 to 3.0% by weight,
More preferably, the content is in the range of 0.2 to 2.0% by weight.

The polylactic acid-based fiber preferably has a dry heat shrinkage at a temperature of 120 ° C. × 15 minutes of 20% or less. If the dry heat shrinkage exceeds 20%, the obtained nonwoven fabric tends to have poor thermal stability.

The fineness of the single fiber of the polylactic acid fiber may be appropriately selected, but is preferably 0.5 denier or more. If the single yarn fineness is less than 0.5 denier, the production amount tends to decrease, and when the number of spinnerets is increased to improve the production amount, the spinning process becomes unstable. Although the upper limit of the single-filament fineness is not particularly limited, for example, when a high-pressure liquid flow treatment is used as the nonwoven fabric treatment, if the single-filament fineness exceeds 15 denier, the bending strength increases, and the entanglement in the high-pressure liquid flow treatment is increased. And the mechanical strength of the obtained nonwoven fabric tends to be inferior, which is not preferable.

The nonwoven fabric of the present invention comprises the above-mentioned polylactic acid-based fiber and a fiber having a water absorption of not less than the official moisture content of 5%. As the fiber having an official moisture content of 5% or more, natural fibers such as cotton, pulp, hemp, wool, and silk can be used. Viscose rayon, copper ammonia rayon obtained from pulp, and lyocell, which is a solvent-spun rayon, can also be used as the recycled fiber. Further, even among synthetic fibers, those containing a polyetheresteramide, those containing a modified polyalkylene oxide or the like can be used.
In addition, fibers having an official moisture content of 5% or more are the same as those described above.
It may be a mixture of more than one kind.

By mixing fibers having an official moisture content of 5% or more with the nonwoven fabric of the present invention, sufficient water absorption and water retention can be imparted to the nonwoven fabric. Such a nonwoven fabric is suitably used for applications such as clothing having excellent sweat absorption properties and wipers having excellent moisture wiping properties. In addition, fibers having an official moisture content of 5% or more are excellent in water absorption, and thus contribute to the manifestation of the bacteriostatic and antibacterial properties of the polylactic acid-based fibers described below.

Natural fibers and regenerated fibers which are fibers having an official moisture content of 5% or more have the property of being degraded by microorganisms in nature in the same manner as polylactic acid-based fibers, and are therefore suitable for applications requiring biodegradability. Can be used.

The form of the polylactic acid-based fibers and fibers having an official moisture content of 5% or more used in the present invention may be short fibers or long fibers. Further, the nonwoven fabric may be a mixed form of short fibers, a mixed form of short fibers and long fibers, or a mixed form of long fibers, but both of them (polylactic acid-based fibers and fibers having an official moisture content of 5% or more) ) Are preferably uniformly mixed, so that both are in the form of short fibers, and are preferably nonwoven fabrics in which short fibers are mixed.

The nonwoven fabric of the present invention is provided with a hydrophilic surfactant. Examples of the hydrophilic surfactant include an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant. Surfactants and the like are used, and these are used alone or in combination. The surfactant may be sprayed onto the nonwoven fabric in the form of an aqueous solution or aqueous dispersion adjusted to a predetermined concentration (for example, about 1 to 1.5% by weight). Before mixing the constituent fibers (in the fiber manufacturing process, etc.), the polylactic acid-based fiber and / or the official moisture content is 5%.
The above fibers may be sprayed. When these are short fibers, when sprayed on a mixed cotton web in the cotton mixing step, the short fibers to which the surfactant has been imparted are reduced in entanglement when the fibers are opened by an opening device such as a card machine, or When the nonwoven web is transported by a roll or the like, it is preferable because it is difficult to wind around the roll or the like, and the fiber is easily entangled during high-pressure liquid flow treatment.

The amount of the hydrophilic surfactant provided to the nonwoven fabric is preferably 100 ppm or more. 100pp
If it is less than m, the antibacterial effect of the nonwoven fabric tends to be insufficiently exerted.

Since the polylactic acid-based polymer is hydrophobic, the fiber made of the polylactic acid-based polymer is also hydrophobic. Such a hydrophobic polylactic acid-based fiber, even if the material itself has antibacterial properties, that is, lactic acid, lactide and other oligolactic acid in the polylactic acid-based polymer constituting the polylactic acid-based fiber described below Does not exhibit an antibacterial effect that actively suppresses the growth of bacteria. It is presumed that the surface of the polylactic acid-based fiber becomes hydrophilic by the addition of the hydrophilic surfactant, so that it can be brought into contact with bacteria and the proliferation of bacteria can be suppressed. Furthermore, the nonwoven fabric of the present invention is in a state where fibers having an official moisture content of 5% or more and polylactic acid-based fibers are mixed, and the fibers are adjacent to each other.
Since it is in a state of being in contact with the moisture contained in the fiber having an official moisture content of 5% or more, it is presumed that the fiber easily comes into contact with the bacteria and the propagation thereof can be suppressed.

It is presumed that such an antibacterial effect is exerted because a small amount of lactic acid, lactide and other oligolactic acid are contained in the polylactic acid polymer constituting the polylactic acid fiber. You. The polylactic acid-based polymer constituting the polylactic acid-based fiber preferably contains 0.01 to 1.0% by weight of lactic acid, lactide and other oligolactic acid. If the content of lactic acid, lactide and other oligolactic acid is less than 0.01% by weight, the effect of antibacterial performance is weakened, while if it exceeds 1.0% by weight, it is hydrolyzed by moisture such as moisture in the air even at room temperature even at room temperature. Progresses, resulting in a tendency to lack long-term storage stability.

In the present invention, in order for the amounts of lactic acid, lactide and other oligolactic acids contained in the polylactic acid-based polymer constituting the polylactic acid-based fiber to fall within the above range,
Adjusting the reaction conditions during the polymerization process, or
After the polymerization is completed, the pressure is reduced in a molten state to remove excess lactide, oligolactic acid and the like.

The nonwoven fabric of the present invention has a bacteriostatic activity value of 2.2 or more according to a unified test method (test method for antibacterial effect approved by the Textile Sanitary Processing Council). The bacteriostatic activity value is defined as B (cells / ml), which is obtained by inoculating a standard sample and a target sample with a certain number of test bacteria and culturing the standard sample for a certain period of time.
After culturing for a certain period of time, the viable cell count of the target sample was determined as C (cells / cells).
ml) and logB-logC. If the bacteriostatic activity value is less than 2.2, it cannot be said that the proliferation of bacteria can be suppressed.

The nonwoven fabric of the present invention comprises a nonwoven web in which polylactic acid-based fibers and fibers having an official moisture content of 5% or more are mixed.
The constituent fibers are combined and integrated by a heat bonding treatment, a mechanical entanglement treatment, or the like.

As the heat bonding treatment, a method of applying a hot air treatment to melt and bond the fibers at the intersections of the constituent fibers, passing a nonwoven web through a hot embossing device comprising an embossing roll and a flat roll or a pair of embossing rolls, A method of melting and bonding the thermoplastic fiber in a portion that abuts on the convex portion of the roll may be used.

Examples of the mechanical entanglement treatment include a method in which the constituent fibers are entangled by a needle punch, and a method in which the constituent fibers are entangled by the action of a high-pressure liquid flow (spunlace method). From the viewpoint of the flexibility of the obtained nonwoven fabric, it is preferable that the constituent fibers are entangled by the action of the high-pressure liquid flow.

In addition, a combination of both the mechanical entanglement treatment and the thermal bonding treatment, that is, a non-woven fabric in which the constituent fibers subjected to the mechanical entanglement treatment are three-dimensionally entangled, is subjected to a thermal adhesion treatment, Strengthening the bond between constituent fibers,
A nonwoven fabric having excellent shape stability may be used.

Polylactic acid-based fiber of non-woven fabric and official moisture content of 5%
The mixing ratio (% by weight) with the above fibers is 70/30 to 3
It is preferably 0/70. When the proportion of the polylactic acid-based fiber is less than 30% by weight, the antibacterial effect aimed at by the present invention tends not to be obtained, and when it exceeds 70% by weight, the water absorption of the nonwoven fabric tends to be poor.

The basis weight of the nonwoven fabric may be appropriately selected according to the intended use, but is preferably in the range of 30 to 150 g / m ² . When the basis weight is less than 30 g / m ² , the formation of the nonwoven fabric is inferior, and the morphological stability and dimensional stability of the nonwoven fabric tend to be poor. On the other hand, when the basis weight exceeds 150 g / m ² , when high-pressure liquid flow treatment is used as a means for entanglement of the constituent fibers, processing energy becomes large, which is not economically preferable. Further, in some cases, the fibers are not sufficiently entangled with each other in the inner layer of the nonwoven fabric, and the nonwoven fabric tends to have a low mechanical strength.

The compression stiffness of the nonwoven fabric of the present invention is 0.15.
It is preferably 0.80 g / (g / m ² ). If the compression stiffness is less than 0.15 g / (g / m ² ), it may be too soft and inferior in mechanical performance. On the other hand, when the compression softness exceeds 0.8 g / (g / m ² ), the hand of the nonwoven fabric tends to be hard.

Next, a preferred production method of the present invention will be described. First, a method for producing a polylactic acid-based fiber will be described. Since it is preferable to uniformly mix the fiber with a fiber having an official moisture content of 5% or more, a method for producing a short fiber as a polylactic acid-based fiber will be described. The above-mentioned polylactic acid-based polymer is heated and melted and discharged from a spinneret, and the obtained spun yarn is cooled by a cooling air using a known cooling device such as a horizontal spray or an annular spray, and then taken out. It is wound on a winder as an undrawn yarn via a roller. The take-up roller speed is 500 to 2000 m / min. Then, a plurality of the undrawn yarns wound are aligned and drawn between a group of rollers having different peripheral speeds by a known drawing machine. Next, a press-type crimp is applied to the drawn tow, a finishing oil agent is applied in an amount of about 0.1 to 0.5% by weight, and cut into a predetermined fiber length to obtain short fibers. It is preferable to include a hydrophilic surfactant in the finishing oil. The stretch tow may be subjected to heat setting at a temperature equal to or lower than the melting point of the material, depending on the use.

On the other hand, short fibers having an official moisture content of 5% or more are prepared. At this time, a hydrophilic surfactant may be added to short fibers having an official moisture content of 5% or more.

Polylactic acid-based staple fibers and staple fibers having an official moisture content of 5% or more are mixed at a mixing ratio of preferably 70/30 to 30/70 (weight ratio), and the mixture is subjected to a predetermined method by a card method or an air lay method. Create a basis weight or non-woven web. At this time, in the card method, the degree of arrangement of the constituent fibers can be appropriately selected depending on the card machine. As the arrangement pattern of the constituent fibers of the nonwoven web, a parallel web in which the constituent fibers are arranged in one direction, a web in which the parallel webs are cross-laid, a random web in which the constituent fibers are randomly arranged,
Alternatively, a semi-random web or the like which is arranged at an intermediate level may be used.

The obtained non-woven web is subjected to a high-pressure liquid flow treatment to three-dimensionally entangle the constituent fibers. The three-dimensional entanglement referred to herein means that the fibers constituting the nonwoven web are entangled not only in the vertical / horizontal direction but also in the thickness direction of the nonwoven fabric and have an integrated structure. Say.

The high-pressure liquid flow treatment referred to here means, for example, a hole diameter of 0.05 to 1.5 mm, preferably 0.1 to 0.4 m.
A device is used in which a plurality of m injection holes are arranged in one row or a plurality of rows at a hole interval of 0.05 to 1.5 mm. A jet of water, i.e., a high-pressure liquid flow, obtained by jetting at a high pressure from the injection hole is jetted, and collides with a nonwoven web placed on a porous support member. It is confounded and integrated.

The jet holes are arranged in rows in a direction perpendicular to the direction of travel of the nonwoven web. As a high pressure liquid flow,
Room temperature or hot water can be used. The distance between the injection hole and the nonwoven web is preferably 10 to 150 mm.
If this distance is less than 10 mm, the formation of the nonwoven fabric obtained by this treatment is disturbed, while the distance is 150 mm
If it exceeds, the impact force when the liquid stream collides with the nonwoven web tends to be low, and confounding integration tends to be insufficient.

The processing pressure of this high pressure liquid stream is between 20 and 20
0 kg / cm ² . In addition, depending on the basis weight of the nonwoven web to be treated, etc., within the range of the treatment pressure, it is possible to obtain a nonwoven fabric which is bulky and excellent in flexibility when the treatment pressure is low, and is constituted when the treatment pressure is high. It is possible to obtain a nonwoven fabric in which the entanglement between the fibers is dense and the mechanical performance is excellent.
When the pressure of the high pressure liquid stream is less than 20 kg / cm ^2, interlacing integrated is not sufficiently performed, becomes a nonwoven fabric having poor mechanical strength, the impact by the water pressure exceeds 200 kg / cm ^2, in an extreme case In addition, the constituent fibers are cut, and fluff is easily generated on the surface of the obtained nonwoven fabric.

As the porous supporting member for supporting the nonwoven web used in applying the high-pressure liquid flow, for example, 20 to 20
There is no particular limitation as long as the high-pressure liquid flow penetrates the nonwoven web and the support member, such as a mesh screen or a perforated plate made of a 200-mesh wire mesh or a synthetic resin.

After the high-pressure liquid flow was applied from one side of the nonwoven web, the entangled nonwoven web was subsequently inverted and subjected to the high-pressure liquid flow treatment from the other side, so that the front and back sides were densely entangled. Since a nonwoven fabric can be obtained, it may be applied to a nonwoven web having a large basis weight or the like according to the use of the nonwoven fabric.

After the high pressure liquid flow treatment, excess moisture is removed from the treated nonwoven web. A known method can be used to remove the excess water, and the excess water is mechanically removed to some extent using a squeezing device such as a mangle roll. Then, the remaining moisture is removed using a drying device such as a suction band type hot air circulation dryer.

After removing the water, if necessary, it may be passed through an embossing device to partially form a heat-bonded region, thereby forming a nonwoven fabric having excellent form stability. Further, after removing water, the polylactic acid-based polymer may be softened or melted by passing through a hot-air treatment machine to bond the fibers at the intersections of the constituent fibers.

Since the hydrophilic surfactant applied to the fibers is slightly removed by the high-pressure liquid flow treatment, an aqueous solution of the hydrophilic surfactant may be sprayed on the obtained nonwoven fabric.

[0043]

The present invention will be described below in detail with reference to examples. Note that the present invention is not limited to only these examples. In the examples, each property value was obtained as follows. The evaluation of the antibacterial property, that is, the bacteriostatic activity value was determined by the method described above. (1) Melting point (° C.): The temperature at which the extreme value of the melting endothermic curve obtained by using a differential scanning calorimeter DSC-7 manufactured by Perkin Elmer at a heating rate of 20 ° C./min is determined as the melting point. (° C.).

(2) Melt flow rate (hereinafter referred to as MFR)
That. ) (G / 10 min): The melt discharge amount at 210 ° C. under a load of 2160 g was measured according to the method described in ASTM D1238.

(3) Intrinsic viscosity of polylactic acid: Measured at a sample concentration of 0.5 g / dl and a temperature of 20 ° C. using a mixed solution of an equal weight of phenol and ethane tetrachloride as a solvent.

(4) Weight (g / m ² ): Ten samples each of 10 cm long × 10 cm wide were prepared from the sample in the standard condition, and after reaching equilibrium moisture, the weight (g) of each sample piece was measured. The weight was weighed, and the average of the obtained values was converted per unit area to obtain the basis weight (g / m ² ).

(5) Tensile strength (kg / 5 cm width): JI
According to the strip method described in SL 1906, ten sample pieces each having a sample length of 20 cm and a sample width of 5 cm were prepared, and a constant-speed elongation type tensile tester (Tensilon UTM-4-1- manufactured by Toyo Baldwin Co., Ltd.) was used. Using 100), each sample piece was stretched at a grip interval of 10 cm and a tensile speed of 10 cm / min to determine the maximum tensile strength (kg / 5 cm width), and the average value of the obtained maximum tensile strength was used as the tensile strength (kg). / 5 cm width).

(6) Flexural softness (g / (g / m ² )):
Five sample pieces each having a width of 5 cm and a length of 10 cm were prepared, and each sample piece was bent in the longitudinal direction to form a cylindrical body. Next, for each measurement sample, a constant speed elongation type tensile tester (Tensilon UTM-4-1-10 manufactured by Toyo Baldwin Co., Ltd.)
0) at a compression speed of 5 cm / min, and divide the obtained maximum load value (g) by the basis weight (g / m ² ) to obtain an average value. ² ))

(7) Antibacterial performance: The antibacterial activity was evaluated by measuring the bacteriostatic activity value by a unified test method (antibacterial effect test method approved by the Textile Sanitary Processing Council). In the evaluation, Staphylococcus a
ureus ATCC 6538P (Staphylococcus aureus) was used. That is, 0.4 ml of a sterilized sample placed in a vial is inoculated as uniformly as possible with 0.2 ml of a bacterial solution having a viable cell count adjusted to 1 ± 0.3 × 10 ^5, and cultured at 37 ° C. for 18 hours. Twenty ml of physiological saline containing 0.2% of Twin 80 is added, and the mixture is stirred to wash out the bacteria. A 10-fold dilution series was prepared, diluted with a nutrient agar medium, cultured at 37 ° C. for 24 hours or more, the number of colonies was counted, and the number of viable bacteria was determined.

For the calculation of the bacteriostatic activity value, the above test was performed on each of the standard sample and the test sample, and the bacteriostatic activity value was determined from the following equation. In addition, a nylon standard white cloth was used as a standard sample. Bacteriostatic activity = logB-logC B: Number of bacteria recovered after 18 hours of cultivation of standard sample C: Number of bacteria recovered after cultivation of test sample for 18 hours

(8) Water absorption (mm / 10 minutes): JIS
The measurement was performed according to the Bilek method described in L1096.

(9) Biodegradation performance: The nonwoven fabric was buried in the soil and taken out after 6 months, and the nonwoven fabric was evaluated according to its form or strong retention as follows. ：: When the morphology is not maintained, or even when the morphology is maintained, the strength is 50 times the strength initial value before burial.
%: When the strength exceeds 50% of the initial strength before burial

Example 1 A polylactic acid-based short fiber was prepared by melting at 170 ° C.
FR 25 g / 10 min polylactic acid (copolymerization ratio (molar ratio) of D-lactic acid and L-lactic acid is D / L = 1.7 / 98.3)
It is. ) Based on a master batch containing 20% by weight of titanium oxide and melted, and then melt-spun from a spinneret at a spinning temperature of 210 ° C and a single hole discharge rate of 0.52 g / min. did. Next, it was wound up as an undrawn yarn through a take-up roll at a take-up speed of 800 m / min. Next, a plurality of obtained undrawn yarns are drawn and aligned to form a tow, and drawn at a draw ratio of 2.6 times using a known drawing machine having a different peripheral speed, followed by a push-in type crimping device. A crimp is applied, and polyethylene glycol monooleate (hydrophilic surfactant) having a molecular weight of 600 is added to 2
0.3% by weight of a finishing oil containing 0% by weight was applied.
Thereafter, the tow was dried and cut into a fiber length of 51 mm to obtain 2.4 denier polylactic acid-based short fibers. The single yarn strength of the obtained polylactic acid-based short fiber is 3.0 g / denier,
The dry heat shrinkage in an atmosphere at 120 ° C. for 15 minutes is 3.
3%.

As the short fiber having an official moisture content of 5% or more, bleached cotton of an average fineness of 1.5 denier and an average fiber length of 24 mm was prepared.

Then, 50% by weight of the above-mentioned polylactic acid-based short fibers and 50% by weight of water-absorbing short fibers were mixed, and a nonwoven web having a basis weight of 50 g / m ² was obtained using a parallel card machine.

Moving 100 mesh metal mesh
The nonwoven web is loaded on the screen and
Was applied. This high pressure liquid flow treatment has a pore diameter of 0.12 mm.
In the three-group arrangement, the injection holes of
Using the placed high pressure liquid flow treatment device, the nonwoven web
The liquid flow pressure is 70 kg / cm from the position 50 mm above ^Two
G was performed under the conditions of G.

Excess moisture is removed from the entangled nonwoven fabric by mangle and dried by a dryer at 100 ° C. to obtain a nonwoven fabric of the present invention (having a hydrophilic surfactant of 200 pp).
m adhesion) was obtained.

Example 2 The nonwoven fabric of the present invention (hydrophilic surfactant) was prepared in the same manner as in Example 1 except that the mixing ratio of polylactic acid-based short fibers and short fibers having an official moisture content of 5% or more was 30/70. 120 ppm of the agent).

Example 3 A nonwoven fabric (having a hydrophilic surfactant of 280 ppm) was prepared in the same manner as in Example 1 except that the mixing ratio of the polylactic acid-based short fibers and the short fibers having water absorbency was 70/30. Obtained.

Example 4 Example 1 except that the basis weight of the nonwoven web was 80 g / m ^2.
Non-woven fabric (200 ppm hydrophilic surfactant)
Adhesion).

Example 5 Example 1 was repeated except that the basis weight of the nonwoven web was 30 g / m ^2.
Non-woven fabric (200 ppm hydrophilic surfactant)
Adhesion).

Example 6 A nonwoven fabric (200 ppm of hydrophilic surfactant adhered) was obtained in the same manner as in Example 1 except that a core-sheath type composite short fiber was used as the polylactic acid-based short fiber. The core-sheath type composite short fiber was produced as follows.

The polylactic acid (D / L = 12/88) having a melting point of 126 ° C. and an MFR of 12 g / 10 min, and the polylactic acid (D / L of a melting point of 171 ° C. and an MFR of 25 g / 10 min used in Example 1) were used.
= 1.7 / 98.3) and 1: 1 by weight, and then polylactic acid having a low melting point (D / L =
12/88) shows that titanium oxide is contained in the molten polymer at 0.5.
% Of titanium oxide was kneaded.

Next, polylactic acid (D / L = 12/88) having a low melting point has a sheath portion and a high melting point, using a separate extruder type melt extruder and a core-sheath type spinneret. The spinning temperature is 210 ° C. and the single-hole discharge amount is 0.5 so that polylactic acid (D / L = 1.7 / 98.3) becomes the core.
Melt spinning was performed from the spinneret under the condition of 2 g / min. After the spun yarn is cooled by the cooling device, the take-up speed is 80
It was wound up as an undrawn yarn via a take-up roll of 0 m / min. Next, a plurality of obtained undrawn yarns are drawn and aligned to form a tow, and drawn at a draw ratio of 2.6 times using a known drawing machine having a different peripheral speed, followed by a push-in type crimping device. A crimp was applied, and 0.3% by weight of a finishing oil containing 20% by weight of polyethylene glycol monooleate (hydrophilic surfactant) having a molecular weight of 600 was applied. 51
The fiber was cut to a fiber length of 2.5 mm to obtain 2.4 denier polylactic acid-based short fibers. The single yarn strength of the obtained polylactic acid-based short fiber was 3.2 g / denier.

The physical properties of Examples 1 to 6 are shown in Table 1.

[0066]

[Table 1]

As is clear from Table 1, Examples 1 to 5
Is a non-woven fabric in which the constituent fibers are entangled by mixing a polylactic acid-based short fiber and a water-absorbing short fiber, and subjected to liquid flow treatment. It was excellent.

In Example 6, a core-sheath conjugate short fiber composed of a polylactic acid-based polymer having a different copolymerization ratio between the D-form and the L-form was mixed with water-absorbing short fiber, and a liquid flow treatment device was used. It was a non-woven fabric subjected to confounding treatment, and had excellent tensile strength, bacteriostatic / antibacterial properties, water absorption, and flexibility.

[0069]

According to the present invention, a non-woven fabric comprising a polylactic acid-based fiber and a fiber having an official moisture content of 5% or more is provided with a hydrophilic oil agent. It is considered that since the surface of the system fiber becomes hydrophilic, contact with bacteria becomes possible, and the bacteriostatic and antibacterial effect of suppressing the growth of bacteria can be exerted. Also,
Since the nonwoven fabric of the present invention contains fibers having an official moisture content of 5% or more, the nonwoven fabric easily contains moisture in the air, and is in contact with the polylactic acid-based fibers, thereby further contacting with bacteria. It contributes to the development of a bacteriostatic and antibacterial effect, and imparts good moisture absorption and water absorption to the nonwoven fabric itself.

The antibacterial nonwoven fabric of the present invention is extremely safe because the polylactic acid-based polymer exhibits antibacterial properties, and is very safe, and can be used for various packaging materials such as food, wallpaper, various filters, sinks, etc. It can exhibit bacteriostatic and antibacterial properties in various fields such as daily necessities and daily life materials such as draining bags, tablecloths, foot wipe mats, towels, agricultural and horticultural materials, medical and hygiene materials, and clothing. is there.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4C081 AA02 AC05 BA14 BB01 BB07 BB08 CA171 CB041 CC01 CC08 CE09 CE11 CF142 CF21 DA04 DA05 DB01 DC12 EA03 EA12 4L033 AA07 AB07 AC07 AC10 BA14 CA48 4L047 AA21 AA28 AB02 BA04 CA19

Claims (4)

[Claims] 1. A non-woven fabric comprising a polylactic acid-based fiber and a fiber having an official moisture content of 5% or more. A hydrophilic surfactant is applied to the non-woven fabric, and the bacteriostatic activity value is 2.2 or more. An antibacterial nonwoven fabric, characterized in that: 2. A non-woven fabric containing 100 P of a hydrophilic surfactant.
2. The antibacterial nonwoven fabric according to claim 1, wherein the nonwoven fabric is provided with not less than pm. 3. The polylactic acid-based fiber is poly (D-lactic acid),
Poly (L-lactic acid), copolymer of D-lactic acid and L-lactic acid, D-lactic acid
Any polymer selected from a copolymer of lactic acid and hydroxycarboxylic acid, a copolymer of L-lactic acid and hydroxycarboxylic acid, a copolymer of DL-lactic acid and hydroxycarboxylic acid, or a blend thereof The antibacterial nonwoven fabric according to claim 1 or 2, wherein 4. A fiber having an official moisture regain of 5% or more,
4. The composition according to claim 1, wherein the content is 0% by weight.
The antibacterial nonwoven fabric according to any one of the above.