JP2000328422A - Antibacterial and antifungal polylactic acid structure and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an antibacterial and antifungal polylactic acid structure having excellent antibacterial and antifungal properties, and biodegradability, and further having adequate treatability, compression-resisting properties and the like, and further to provide a production method thereof. SOLUTION: This antibacterial and antifungal polylactic acid structure is a three-dimensional structure obtained by repeatedly bending filaments having 300-100,000 de sizes and consisting essentially of a thermoplastic polylactic acid resin to connect the filaments at the majority of the contacting parts. The structure has 0.005-0.2 g/cc apparent density, and the polylactic acid resin contains 0.01-10 wt.% oligomer component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antibacterial and antibacterial polymer which is formed into a three-dimensional structure by filaments made of thermoplastic polylactic acid resin and has excellent antibacterial and antifungal properties and biodegradability. The present invention relates to a lactic acid structure and a method for producing the same.

[0002]

2. Description of the Related Art At present, a three-dimensional network structure made of polyvinyl chloride or polypropylene is used as a cushion material for a bed, an entrance mat (Japanese Patent Application Laid-Open No. 01-207462, etc.), a drain material for soil improvement (Japanese Patent Application Laid-Open No. No. 47-44839). They do not decompose spontaneously, and when incinerated upon disposal, problems such as generation of toxic gas and damage to incinerators occur. Therefore, they are often used for landfill, and landfill sites have become scarce. For this reason, if left in the natural environment due to illegal dumping, animals will inadvertently eat and die, and additives such as plasticizers will flow out and act as environmental hormones, causing environmental pollution, and increasing environmental pollution. Have been.

In order to solve these problems, studies on biodegradable polymers have been conducted. In particular, if the plant resources are used as raw materials and easily decomposed and oligomerized by enzymes or microorganisms, they become useful composts for plant growth, and are eventually decomposed into water and carbon dioxide, which are then converted back into plant resources via photosynthesis. Renewable polylactic acid is attracting attention. In addition to photosynthesis, polylactic acid can be directly recycled as a lactic acid by hydrolysis or as a lactide by a cyclization reaction, by a raw material recovery method.

[0004] At present, polylactic acid, which is also a biocompatible sustained-release polymer, has been used as a film, a fiber, and a molded product for medical and agricultural purposes in addition to general household products. Thus, polylactic acid is trying to gain a position as a general-purpose resin instead of a petrochemical resin.

[0005]

On the other hand, in recent years, as a need for petrochemical resin applications, the need for antibacterial and antifungal properties has increased due to the problem of nosocomial infection caused by Staphylococcus aureus, and antibacterial properties have been increased for living materials and hospital supplies. Many have been provided with antifungal properties. Thus, polylactic acid having an antibacterial and antifungal function has not yet been proposed.

Accordingly, it is an object of the present invention to provide an antibacterial and antifungal polylactic acid structure having excellent antibacterial properties, antifungal properties and biodegradability, and having appropriate handling properties and anticompression properties, and the like. It is to provide a manufacturing method thereof.

[0007]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that an appropriate amount of oligomer is added to polylactic acid in which a catalyst for suppressing thermal decomposition has been deactivated. It has been surprisingly found that the addition of an antibacterial and fungicide can provide antibacterial and fungicidal properties without adding any antibacterial and fungicide, and the present inventors have further studied and arrived at the present invention.

That is, the antibacterial and antifungal polylactic acid structure of the present invention has a fineness of 300 to 100,000 denier, and a filament mainly composed of a thermoplastic polylactic acid resin is repeatedly bent to form most of the contact portion. A three-dimensional structure joined by
The apparent density is 0.005 to 0.2 g / cc, and the polylactic acid resin contains the oligomer component in an amount of 0.01 to 10% by weight. The oligomer component in the present invention refers to a component having a number average molecular weight of 100 to 3,000, and also includes a cyclic compound such as lactide.

In the above, it is preferable that the melting point of the polylactic acid resin is 150 ° C. or higher. The melting point indicates an endothermic peak temperature derived from crystal melting measured by a differential scanning calorimeter DSC.

The above-mentioned oligomer component refers to those described above, and the preferred number-average molecular weight of the oligomer component is 100 to 100.
It is preferably 1,000, particularly preferably a chain dimer of lactide or lactic acid, or a mixture thereof.

As the cross-sectional shape of the filament, any shape can be used, but a hollow cross-section or an irregular cross-section is preferable.

On the other hand, in the production method of the present invention, a melt mainly composed of a thermoplastic polylactic acid resin containing 0.01 to 10% by weight of an oligomer component is discharged downward from a nozzle having a plurality of orifices. It is characterized by being sandwiched and cooled by a take-up device while being brought into contact with and joined to each other while being repeatedly bent in a molten state.

[Function and Effect] In the antibacterial and antifungal polylactic acid structure of the present invention, a relatively thick filament is repeatedly bent to form a coil spring-like or loop-like portion in the three-dimensional structure. Therefore, the portion can be suitably deformed with respect to the compressive stress and the stress can be dispersed, so that the compressive recovery is superior to the straight beam structure. In addition, it is a thick line with fineness, and it has a large void because of its low apparent density, and it has excellent air permeability and water permeability,
Moreover, the shape holding force is high. Further, since the surface area of the filament is small, it is excellent in drainage and drying. In addition, since it contains an oligomer component, it has excellent antibacterial and antifungal properties, so that it can be used safely even in an environment where bacteria and fungi are likely to occur. Furthermore, when it is no longer needed, it is excellent in environmental compatibility that can be recycled without causing environmental pollution. As a result, it is possible to provide an antibacterial and antifungal polylactic acid structure having excellent antibacterial properties, antifungal properties and biodegradability, and having appropriate handling properties and elasticity.

When the melting point of the polylactic acid resin is 150 ° C. or higher, the heat resistance is improved, and problems during production due to decomposition during melting can be reduced.

When the oligomer component is mainly composed of a lactide, a chain dimer of lactic acid, or a mixture thereof, the reason why the elucidation has not been elucidated, but a more preferable antibacterial and antifungal function is exhibited. It has been found.

When the cross-sectional shape of the filament is a hollow cross-section or a modified cross-section, the second moment of area of the filament becomes high, so that the fineness is reduced and the rigidity is required. It can be suitably used for required applications.

On the other hand, according to the production method of the present invention, antibacterial and antifungal polylactic acid having excellent antibacterial properties, antifungal properties and biodegradability as described above, and having appropriate handling properties and elasticity. The structure can be continuously manufactured at a low cost with a simple device and a simple process.

[0018]

Embodiments of the present invention will be described below in detail. The antibacterial and antifungal polylactic acid structure of the present invention is a three-dimensional structure in which a filament mainly composed of a thermoplastic polylactic acid resin is repeatedly bent and joined at most of the contact portions.

The thermoplastic polylactic acid resin referred to in the present invention is:
Average molecular weight 5 polymerized using lactic acid or lactide as the main raw material
It refers to polylactic acid (hereinafter abbreviated as PLA) containing 0000 to 500,000 of polyhydroxycarboxylic acid as a main component.
In the antibacterial and antifungal polylactic acid structure of the present invention (hereinafter abbreviated as PLA structure), if the average molecular weight of PLA is less than 50,000, the strength of the structure tends to be too weak to be a brittle PLA structure. If the average molecular weight exceeds 500,000, the melt viscosity tends to be too high, making it difficult to form a PLA structure. Therefore, the preferred average molecular weight of PLA is from 100,000 to 400,000. In addition,
The average molecular weight referred to in the present invention is a weight average molecular weight measured using GPC (gel permeation chromatography).

The melting point of the PLA constituting the PLA structure of the present invention is preferably 150 ° C. or higher, more preferably 170 ° C. or higher, from the viewpoint of heat resistance. When using amorphous PLA that does not show a melting point in the present invention, it is preferable to use it after examining its use because heat resistance is restricted. Note that the PLA of the present invention usually performs melt extrusion to form a structure, so that thermal decomposition during melting is suppressed.
It is preferred to deactivate the catalyst or block the acid end.

The polymerization method of PLA is described in, for example,
There is a method using a metal or a metal compound of the IA group, IVA group, IVB group, or VA group of the periodic table such as tin octylate disclosed in JP-A-14688 or the like as a catalyst. The method is not limited, and all known manufacturing methods can be applied. For example, JP-A-7-33861
And lactide directly or from lactide by a method disclosed in JP-A-10-158370 and JP-A-10-158370.

The present invention is characterized in that the above PLA contains 0.01 to 10% by weight of its oligomer component. Although the reason has not been elucidated, it has been surprisingly found that when the oligomer component in the above range is contained, antibacterial and antifungal properties are exhibited. If the content is less than 0.01% by weight, it does not exhibit antibacterial properties, which is not preferable. If it exceeds 10% by weight, the melting point and the heat resistance decrease, and the occurrence of troubles due to the sublimation of the oligomer during formation of the structure becomes remarkable. The preferred oligomer content of the present invention is 0.1.
It is from 1% by weight to 5% by weight, more preferably from 0.2% by weight to 2% by weight.

The amount of the oligomer may be adjusted by a method of leaving an appropriate amount of the oligomer at the time of polymerization or a PLA having a small content of oligomer in which the amount of the catalyst is reduced to make it higher in molecular weight to deactivate the catalytic activity or to block the acid terminal. A necessary amount of a preferable oligomer can be contained by a method of adding and kneading the oligomer before melt spinning. In addition, known additives such as a stabilizer, a plasticizer, and a coloring agent can be added to the PLA constituting the present invention as needed, to the extent that the characteristics are not impaired.

The PLA structure of the present invention has a PL
A is a three-dimensional structure in which filaments having a fineness of 300 to 100,000 deniers are repeatedly bent and joined at most of the contact portions, and have an apparent density of 0.005 to 0.5.
2 g / cc. Principal applications of the antibacterial and antifungal PLA structure of the present invention include living materials, cushioning materials, agricultural materials, civil engineering materials, and the like, and it is desirable to individually impart properties suitable for these applications.

The fineness of the filaments constituting the PLA structure is 30
It is 0 to 100,000 denier. If it is less than 300 denier, the compression resistance of the three-dimensional three-dimensional structure is reduced, and the shape retention is poor. If it exceeds 100,000 denier, the anti-compression property is sufficiently satisfied, but in the case of a structure having a certain number of constituents, the apparent density becomes large and the handling property is inferior.

Since the preferred fineness varies depending on the application, the preferred range for each application is as follows. In living materials, if a soft touch is desired, it is 300 to 5000 denier, more preferably, 500 to 2,000 denier, and if a hard touch is desired, 2,000 to 50,000 denier, more preferably, 3,000 denier. 20,000
Denier. The cushion material has a denier of 500 to 20,000, more preferably 1,000 to 5,000. 200 when buried in soil for drainage as agricultural or civil engineering material
It is from 0 denier to 100,000 denier, more preferably from 5,000 denier to 50,000 denier. When no extreme compressive stress is applied to the waterway for hydroponic cultivation, it is from 500 denier to 5000 denier, more preferably from 1000 denier to 3000 denier. When plant seedlings are grown and maintained for slope protection use, the density is from 2,000 denier to 20,000 denier, more preferably from 3,000 denier to 10,000 denier.

The apparent density of the antibacterial and antifungal PLA structure of the present invention is from 0.005 g / cc to 0.2 g / cc.
If it is less than 0.005 g / cc, the anti-compression property is inferior and is not preferred. Exceeding 0.2 g / cc is not preferred because the weight becomes heavy and the handling properties are poor. The preferred apparent density is 0.01 g / cc to 0.05 g / cc for applications where weight reduction and softening are desired, and more preferably 0.015 g / cc.
g / cc to 0.03 g / cc. 0.03 g / cc to 0.2 g for applications where durability and compression resistance are desired
/ Cc, more preferably from 0.05 g / cc to 0.1 g / cc.

The cross-sectional shape of the above-mentioned filament is not particularly limited. However, when the fineness is required to be stiff or light and the compression resistance is required, the second moment of area of the filament is increased. It is preferable to apply a hollow cross section or a modified cross section. If the hollow ratio of the hollow cross section is not less than 60%, the hollow section may be crushed at the time of forming the hollow, and may be broken by torsional stress even in actual use due to the helical coil spring structure. On the other hand, when the hollow ratio is low, the increase in the second moment of area is small, so that the effect of lightening and compression resistance by hollowing is reduced. Therefore, a preferable hollow ratio is 10% to 5%.
0%, more preferably 15% to 40%.
The same can be said for an irregular cross section.
2 to 4.0, more preferably 1.5 to 3.0.
It is.

The method for producing an antibacterial and antifungal PLA structure according to the present invention is characterized in that a melt mainly composed of a thermoplastic polylactic acid resin containing an oligomer component in an amount of 0.01 to 10% by weight is provided by a nozzle having a plurality of orifices. Discharge downward
It is characterized by being sandwiched and cooled by a take-up device while being brought into contact with and joined to each other while being repeatedly bent in a molten state. Thus, a three-dimensional structure in which the filament mainly composed of the thermoplastic polylactic acid resin is repeatedly bent and joined at most of the contact portions can be formed.

The PLA melt containing the oligomer component is purified under reduced pressure so that a desired residual oligomer remains after reaching a predetermined molecular weight in the polymerization stage, or PLA obtained in a purified state by removing the residual oligomer. A desired amount of oligomer may be contained in PLA by any method such as a method of adding and kneading a predetermined amount of oligomer before spinning or a method of spinning while adding and kneading during spinning. When using PLA containing a large amount of oligomer in the present invention,
It is particularly preferred to block the acid terminal at the start of ring-opening polymerization to suppress hydrolysis.

As a method for forming a three-dimensional network structure, a method described in, for example, US Pat. No. 5,639,543 is exemplified as a preferable method. Hereinafter, this method will be described with reference to the drawings.

As shown in FIG. 1, a general melt extruder 1
And a thermoplastic P containing a predetermined oligomer component
Melt LA resin (or PLA containing no oligomer)
Is used, the oligomer is added in a fixed amount simultaneously with the PLA, preferably while being melt-kneaded by a kneading twin-screw extruder), and the melt is kept at a melting temperature of 10 ° C. to less than 80 ° C. from the melting point by a gear pump or the like. An object is supplied to the back surface of the multi-row nozzle 5 having a plurality of orifices by a predetermined amount. The molten material is discharged downward from the orifice as a molten filament 2, and is repeatedly bent in a molten state below the orifice to form a loop or the like, and is brought into contact with and joined to the three-dimensional structure 3.
To form This is sandwiched by the take-off device 7, cooled by cooling water or the like in the cooling tank 6, pulled up from the water by the feed roller 8, further dewatered, dried, etc., and subjected to an antibacterial and antifungal polylactic acid structure. Is obtained.

If the melting temperature is lower than the melting point by less than 10 ° C., abnormal flow may occur, and the filaments may have large and thin spots, the melt viscosity may be too high to form a loop, or the filament temperature may be too low. It is not preferable because it causes a problem such as lowering and non-joining when the loops come into contact with each other. On the other hand,
When the melting temperature is higher than the melting point by 80 ° C. or more, thermal degradation becomes remarkable, the molecular weight is reduced, and only a fragile PLA structure is obtained, or the contained oligomer undergoes significant sublimation, and the contained oligomer decreases or sublimates into the orifice. It is not preferable because it may adhere and cause hole bending or line breakage. Therefore, the preferred melting temperature is 20 ° C. or more and 60 ° C. or less, more preferably 25 ° C. or more and 40 ° C. or less than the melting point.

Although the shape of the orifice is not particularly limited, it has a hollow cross section (for example, a cross section having a triangular hollow shape, a round hollow shape, a hollow shape with protrusions, etc.) and a modified cross section (triangular shape,
In addition to the above-described effects, the shape of the three-dimensional structure formed by the discharge line in the molten state is suppressed, and the bonding at the contact points is strengthened by adopting a shape in which the second moment of area such as a Y-type or a star is increased. It is particularly preferable because it can be made. Preferably, the apparent hollow rate of the orifice forming the hollow cross section is 90% or less, and the hollow rate of the filament is 60% or less.

In the case of heating for bonding as described in JP-A-1-2075, the three-dimensional structure is easily relaxed and a planar loop structure may occur. is there.

It is preferable that the pitch between the holes of the orifices is a pitch that allows sufficient contact with the loop diameter formed by the filament. The pitch between holes is shortened for a dense structure, and the pitch between holes is increased for a dense structure. The pitch between the holes of the present invention is preferably 3 to 20 mm, more preferably 5 to 1 mm.
0 mm.

In the present invention, different densities and different finenesses can be obtained as desired. Different density layers can be formed by a configuration in which the pitch between rows or the pitch between holes is changed, and a method in which both pitches between rows and between holes are changed. Further, when the cross-sectional area of the orifice is changed to give a pressure loss difference at the time of discharge, a structure composed of different fineness filaments can be formed using the principle that the orifice having a larger pressure loss has a smaller discharge amount. When the pitch between the holes of the orifice having a small cross-sectional area is shortened and the pitch between the holes of the orifice having a large cross-sectional area is widened, a dense structure having a small fineness and a coarse structure having a large fineness can be formed.

The molten wire 2 discharged downward from the nozzle gives a difference between the take-up speed and the drop speed of the wire at a position in contact with the net of the take-up device 7 to form a slack loop or the like. . In addition, the cooling medium (usually, water at room temperature is preferably used at a high cooling rate and at a low cost, and is preferably used) as a continuous cooling medium during a period in which the form of the loop or the like is not deformed due to relaxation by being sandwiched by the net of the take-up device 7. And quench and solidify. The distance between the nozzle surface and the pick-up point is at least 50
Centimeters or less are preferable because it is possible to prevent the molten filament from being cooled and the contact portion from being fused. When the discharge amount of the molten filament is as small as less than 5 g / minute hole, it is preferably 5 cm to 30 cm, and when it is 5 g / minute hole or more, it is preferably 10 cm to 40 cm.

The thickness of the three-dimensional structure 3 is determined by the effective width of the nozzle orifice and the opening width of the net (interval between the nets of the take-off device). When the opening width of the take-off net is made narrower than the effective width of the orifice, and the surface line is bent by 45 ° or more and flattened, the structure surface becomes a reinforcing surface, and rigidity and durability are improved. Becomes

Normally, it is preferable that the opening width of the net is smaller by -5 to -10 mm than the effective width of the orifice. If the width is wider than the effective width of the orifice, there is a tendency that unevenness is generated on the surface or the surface of the structure tends to be uneven. In the case where unevenness is generated, the width of the take-out net on the carry-out side is made smaller than the effective width of the orifice, so that the take-out spot can be prevented. The take-up speed needs to be slower than the drop speed of the filament by at least the slack of the loop diameter. If it is too fast, the loop cannot be formed or the joining of the contact points becomes insufficient. If the speed is too slow, the molten wire stays too high and the density becomes too high. Therefore, the take-up speed of the take-off net is adjusted to a desired apparent density from the balance between the discharge amount and the drop speed due to the melt viscosity of the discharge wire.

The melt viscosity of the filament at the time of forming the structure is 50
0 poise to 10,000 poise is preferable, and 20,000 poise
If the poise is exceeded, the loop formation speed becomes slow. Therefore, it is preferable to adjust the melt viscosity by setting appropriate conditions in terms of the balance between the molecular weight and the spinning temperature.

Next, the resultant is dried with a drain, cut into a desired length, or dried after the cut. The antibacterial and fungicidal PLA structure thus obtained can be adapted to a more preferable use by post-processing or lamination with another material, if desired.

The antibacterial and antifungal PLA structure of the present invention has antibacterial and antifungal properties, a moderate cushioning property, excellent air permeability, drainage and drying properties, and biodegradability. For example, in living material applications, cleaning tools for water and bath mats, toilet mats, sink mats, entrance mats, mats for home planting, garden soil runoff prevention fences, spring water garbage fences, hospital hospital mats, Agricultural materials include hydroponic planting bases, nursery beds, garbage fences for cultivation ponds, drainage materials for wetlands such as paddy fields, and planting and agricultural lands. It is also useful for temporary fishing reefs etc. when assembled into a base of release pesticides and fertilizers, huge structures, and in civil engineering applications,
It is useful for disposable drain materials, slope vegetation protection, sediment runoff prevention fences, bacteria carrying materials for rivers, temporary mats for summer ski slopes, etc.

[0044]

The present invention will be described in more detail with reference to the following examples. The evaluation in the examples was performed by the following method.
"Parts" indicates "parts by weight" unless otherwise specified.

1) Antibacterial activity This was based on the Manual for Quantitative Antibacterial Testing Method for Textile Products, which was established by the Evaluation Committee for New Functions of Textile Products. That is, 0.2 ml of a test bacterial suspension containing 1 ± 0.3 × 10 ⁵ cells / ml of the following test bacteria was inoculated uniformly to 0.4 g of a sample in sterilized 1/20 concentration nutrient broth, 1 at 37 ° C
The cells were cultured for 8 hours. After completion of the culture, the test bacteria were washed out, and a pour plate agar medium was prepared from the solution, and cultured at 37 ° C. for 24-48 hours, and the number of viable bacteria was measured. In addition, about the unprocessed product, the test bacteria were washed out immediately after inoculation, a pour plate agar medium was prepared from the solution, and cultured at 37 ° C. for 24-48 hours to measure the number of viable bacteria inoculated. The antibacterial activity was evaluated by the bacteriostatic activity value according to the following formula. The higher the bacteriostatic activity value, the better the antibacterial property. In addition, Staphylococcus aureus (Staphylococcus aureus) was used as a test bacterium.
ATCC 6538P) was used. Bacteriostatic activity value = LogB-LogC, provided that the test was completed (LogB-LogA)> 1.5
Meet.

A: Average number of bacteria recovered immediately after inoculation of the raw product B: Average number of bacteria recovered after 18 hours of cultivation of the raw product C: Number of bacteria recovered after 18 hours of cultivation of the processed product Average value 2) Antifungal property The growth state of the mold after 4 weeks at 25 ° C. was evaluated by the method of JIS Z-2911. A 50 × 50 mm test piece was placed at the center of a dry heat-sterilized petri dish, one mold spore carrier was placed at the center of the test piece, and a dried glass plate was placed thereon, and the lid was placed thereon. Put this Petri dish at temperature 2
After placing in an apparatus maintained at 8 ° C. and a humidity of 95 to 99% and culturing for 4 weeks, the growth of hypha was determined. The types of mold used in the test were Aspergillus niger, Penicillium citrinum, Ketomium globosum, Cladosporium cladosporioides, and Rhizopus stronifer.

3) Melting point (Tm) The endothermic peak (melting peak) temperature was determined from an endothermic curve measured at a heating rate of 20 ° C./min using a Shimadzu TA50 / DSC50 differential thermal analyzer. I asked.

4) Average molecular weight of PLA The sample PLA was dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol (HFP) to prepare a solution having a concentration of about 0.2% by weight. Gel permeation chromatography (manufactured by Showa Denko KK, format: GPC-
SYSTEM 21 (hereinafter referred to as GPC). The weight average molecular weight (Mw) was calculated using polymethyl methacrylate as a standard substance.

5) Oligomer content Lactide content: A sample was dissolved in deuterated chloroform to prepare a 4.2% by weight solution, and measured using nuclear magnetic resonance spectroscopy (Varian, 200MH-NMR). Then, it was calculated from the area ratio between the main peak of the polymer and the main peak of lactide.

Dimeric lactic acid content: The value obtained by removing the lactide content from the profile obtained from the low molecular weight column in the PLA molecular weight measurement was defined as the dimeric lactic acid content.

6) Apparent Density The sample was cut into a size of 15 cm × 15 cm, the height at four locations was measured, the volume was determined, and the weight of the sample was expressed as a value obtained by reducing the volume by the volume (n = 4). Average).

7) Fineness of filaments Each filamentous portion was cut out from the sample at 10 locations, embedded in acrylic resin, the cross section was cut out, and a slice was prepared to obtain a cross-sectional photograph. The cross-sectional area (Si) of each part was determined from a cross-sectional photograph of each part. Further, the section obtained in the same manner was dissolved in an acrylic resin with acetone, degassed in vacuo, and heated at 40 ° C. using a density gradient tube.
The specific gravity (SGi) measured in was determined. Then, a linear weight of 9000 m was determined from the following equation (unit: cgs).

Fineness = [(1 / n) ΣSi × SGi] × 90000000 8) Hollowness Ratio A value obtained by dividing the hollow area of a cross-sectional photograph taken for fineness measurement by the total cross-sectional area of the fiber including the hollow portion (n = 4) Average value of%
Displayed with.

9) Degree of Deformity The average of the values (n = 4) obtained by dividing the circumscribed circle of the filament in the cross-sectional photograph taken for fineness measurement by the inscribed circle was expressed in%.

10) Bonding Whether or not the samples were bonded by visual judgment was judged by whether or not the fibers at the bonded portion were pulled apart by hand and were not separated (n = 2).
0). Most do not deviate: ◎, those that do not deviate more than 60%: ○, those that do not deviate more than 40%: Δ, less than 40%:
X was determined.

11) Elasticity (cushioning property) Ten panelists stepped on a sample cut into a width of 500 mm and a length of 1000 mm with shoes as a doormat, and evaluated the elasticity by the following judgment based on the tactile sensation at that time. And Concrete: 0 points, board: 2 points, fiber cushion: 5 points, urethane cushion: 10 points, evaluation points: 50 points or more: 、, 20 points or more: ○, 10 points or more:
Δ: Less than 10 points: determined as x.

12) Brittleness The mat used in the evaluation of elasticity was evaluated as "Brittle" when the mat was broken at the time of evaluation, and "Brittle" when not broken.

13) Handleability From a place where 20 samples of 1000 mm in width and 2000 mm in length were piled up, 10 panelists were moved to a place 5 m away, and 20 sheets each were piled up. At this time, the panel was judged to be easy to handle. Good: 10 points, good: 5 points, slightly defective: 2 points, defective: 0 points, and the evaluation score was 50 points or more:
◎, 20 points or more: ○, 10 points or more: △, less than 10 points: ×
It was determined.

14) Heat resistance A load of 5 kg was applied to the entire surface of a 10 cm square sample by 50 mm.
After being left for 22 hours in an atmosphere at 50 ° C., the bulk retention rate when cooled to room temperature and deweighted is 50% or more: 、, 30% or more:
、, 15% or more: Δ, less than 15%: × (n =
4 average).

Example 1 100 parts of L-lactide purified by a conventional method was melted at 190 ° C. in a nitrogen atmosphere, and 0.1 part of a catalyst was added thereto to carry out ring-opening polymerization. To allow the melt viscosity to reach the predetermined viscosity,
It was then pelletized. The resulting PLA has a molecular weight of 32.
0000, melting point 180 ° C, oligomer content 0.0
It was 05% by weight. Then 1500mm, length 12
3.6mm outer diameter, 3.2 inner diameter on 0mm nozzle effective surface
The orifice having a triple bridge having a width of 8.5 mm and a pitch of 8.55 mm and a pitch of 7.36 mm was used in a staggered arrangement of 1425 holes.
Vacuum dried at 0 ° C, 1 part of dimeric lactic acid and 1 part of lactide were added and kneaded at 195 ° C with a twin-screw extruder at a spinning temperature of 200 ° C and a discharge rate of 2800 g / min. Is discharged as a molten line, and the nozzle surface is 150 mm
Cooling water is provided underneath, and a pair of parallelly arranged take-up conveyors having a 1400 mm width stainless steel endless net driven by a drive shaft are exposed to the water surface so that the parallel portions have an opening width of 35 mm intervals. The melted discharge filaments are twisted to form a three-dimensional structure by being in contact with each other while forming a loop to form a three-dimensional structure, and both sides of the molten three-dimensional structure are sandwiched by a take-off conveyor. While
It was drawn into cooling water at 25 ° C. at a speed of 2000 mm per minute, solidified, formed into a three-dimensional structure having both sides flattened, drawn out, drained, cut continuously into a length of 2000 mm, and dried.

The obtained PLA structure has a good bonding condition, an apparent density of 0.040 g / cc, a thickness of 35 mm, and a filament having a triangular tapered hollow section with a hollow ratio of 42% and a fineness of 3000 denier. there were. Also, the PL constituting the structure
The properties of A were such that the molecular weight was 280000, the melting point was 176 ° C., the oligomer content was 2.8% by weight, the lactic acid content of the dimer was 1.4% by weight, and the lactide content was 1.4% by weight. Table 1 shows other evaluation results of the structure. The structure of the present invention exhibits excellent antibacterial and antifungal properties, and is also excellent in elasticity and handleability. The structure was subjected to a wearing test for three months as a bath mat, and no mold growth was observed.

[0062]

[Table 1] Example 2 An orifice having a circular cross section of 1.0 mm in diameter was used on a nozzle effective surface of 1500 mm and a length of 120 mm, and a 1100-hole nozzle having a staggered arrangement of 8.0 mm between holes and 6.93 mm between rows was used. The discharge rate is 1600 g / min,
Except that the opening width was set to 20 mm, P
An LA structure was obtained. This PLA structure has a good bonding state, an apparent density of 0.040 g / cc, a thickness of 20 mm,
The filament had a solid round cross section and a fineness of 2600 denier.
The PLA constituting the structure has a molecular weight of 27000.
0, melting point 174 ° C., oligomer content 2.9% by weight
The lactic acid content of the dimer was 1.5% by weight, and the lactide content was 1.4% by weight. Table 1 shows other evaluation results of the structure. The structure of the present invention exhibits excellent antibacterial and antifungal properties, and is also excellent in elasticity and handleability.

Comparative Example 1 A PLA structure was obtained in the same manner as in Example 2 except that 5 parts of dimeric lactic acid and 6 parts of lactide were added during spinning. This PLA structure has a good bonding state and an apparent density of 0.04.
The filaments were 0 g / cc, 20 mm thick, and had a solid round cross section with a fineness of 2400 denier. In addition, the P
LA had a molecular weight of 210,000, a melting point of 165 ° C., an oligomer content of 12.1% by weight, a dimeric lactic acid content of 5.5% by weight, and a lactide content of 6.6% by weight. Table 1 shows other evaluation results of the structure. In the structure of the present invention out of the range of the oligomer content, remarkable sublimation of the oligomer was caused at the time of spinning. However, it has excellent antibacterial and antifungal properties, and has good handleability, but has somewhat poor elasticity and heat resistance.

Example 3 An orifice having a circular cross section of 0.5 mm in diameter and 2,426 holes in a staggered arrangement with a pitch of 5.0 mm and a pitch of 4.33 mm between rows were formed on an effective surface of a nozzle having a length of 1500 mm and a length of 120 mm. Using a nozzle, a PLA structure was obtained in the same manner as in Example 1, except that the discharge rate was 800 g / min and the distance between the nozzle surface and the water surface was 80 mm. This PLA structure is
The bonding condition was good, the apparent density was 0.020 g / cc, the thickness was 20 mm, and the filaments had a solid round cross section and a fineness of 1200 denier. The PLA constituting the structure has a molecular weight of 240,000, a melting point of 170 ° C, an oligomer content of 3.1% by weight, a dimer having a lactic acid content of 1.6% by weight, and a lactide content of 1. It was 5% by weight. Table 1 shows other evaluation results of the structure. The structure of the present invention is a fine structure having a slightly smaller linear diameter, exhibiting excellent antibacterial and antifungal properties, and having excellent elasticity and handleability.

Comparative Example 2 A PLA structure was obtained in the same manner as in Example 3, except that the discharge rate was 360 g / min. This PLA structure had a poor bonding condition, an apparent density of 0.009 g / cc, and a thickness of 20 m.
m, the filament had a solid round cross section and a fineness of 500 denier. The PLA constituting the structure has a molecular weight of 200.
The melting point was 167 ° C., the oligomer content was 3.8% by weight, the lactic acid content of the dimer was 1.8% by weight, and the lactide content was 2.0% by weight. Table 1 shows other evaluation results of the structure. Unlike the present invention, a structure having a slightly poor bonding state exhibits excellent antibacterial and antifungal properties, but is a structure slightly inferior in elasticity and handleability due to low apparent density.

Comparative Example 3 The discharge rate was 4100 g / min and the take-off speed was 1000 mm
A PLA structure was obtained in the same manner as in Example 2 except that the rate was set to / min. This PLA structure had a good bonding state, an apparent density of 0.205 g / cc, a thickness of 20 mm, and a filament having a solid round cross section and a fineness of 4600 denier. The PLA constituting the structure has a molecular weight of 290000, a melting point of 178 ° C., an oligomer content of 2.5% by weight, a dimeric lactic acid content of 1.3% by weight, and a lactide content of 1.0%. It was 2% by weight. Table 1 shows other evaluation results of the structure. Structures outside the apparent density range of the present invention exhibit excellent antibacterial and antifungal properties, but are poor in elasticity and handleability.

Comparative Example 4 A PLA structure was obtained in the same manner as in Example 3 except that the distance between the nozzle surface and the water surface was changed to 180 mm. This PLA structure had a poor bonding condition, an apparent density of 0.02 g / cc, a thickness of 20 mm, and a filament having a solid round cross section and a fineness of 280 denier. The PLA constituting the structure has a molecular weight of 240,000 and a melting point of 170.
C., the oligomer content was 3.1% by weight, the lactic acid content of the dimer was 1.5% by weight, and the lactide content was 1.6% by weight. Table 1 shows other evaluation results of the structure. Unlike the present invention, a structure having a slightly poor bonding state exhibits excellent antibacterial and antifungal properties, but is a structure slightly inferior in elasticity and handleability due to a fine filament fineness.

COMPARATIVE EXAMPLE 5 A nozzle having a circular orifice shape having a circular cross section and a diameter of 2 was used, the discharge rate was 5250 g / min, and the distance between nozzle water surfaces was 80.
The PLA structure was obtained under the same conditions as in Example 1 except that the mm and the take-up speed were set to 1000 mm / min. This PLA
The structure has a good bonding state and an apparent density of 0.15 g / c.
c, 35 mm in thickness, the filament is a solid round cross section and the fineness is 110
000 denier. PLA constituting the structure
Has a molecular weight of 290000, a melting point of 178 ° C., an oligomer content of 2.7% by weight and a dimeric lactic acid content of 1.
3% by weight and lactide content was 1.4% by weight. Table 1 shows other evaluation results of the structure. Coarse structures out of the fineness range of the present invention exhibit excellent antibacterial and antifungal properties, but are inferior in elasticity and handleability.

Comparative Example 6 The discharge filament obtained under the same conditions as in Example 3 except that the distance between the nozzle water surfaces was 350 mm, solidified before reaching the water surface, did not form a loop, and could form a net-like structure. Did not. No evaluation was performed because no structure was formed.

Comparative Example 7 A molecular weight of 48,000 and a melting point of 142 were obtained in the same manner as in Example 1 except that the polymerization conditions and the conditions for removing residual oligomers were changed.
The PLA having an oligomer content of 10.5% by weight was vacuum-dried to obtain a PLA structure under the same spinning conditions as in Example 2 except that dimer lactic acid and lactide were not added. This PLA structure has a good bonding state and an apparent density of 0.0
The filaments were 40 g / cc, 20 mm thick, and had a solid round cross section and a fineness of 1800 denier. The PLA constituting the structure has a molecular weight of 40,000, a melting point of 135 ° C., an oligomer content of 12.8% by weight, a dimer having a lactic acid content of 6.5% by weight, and a lactide content of 7. It was 4% by weight. Table 1 shows other evaluation results of the structure. A structure using PLA having a low melting point outside the range of the oligomer content according to the present invention exhibits excellent antibacterial and antifungal properties, but is inferior in brittleness, elasticity and handleability. By the way, as in Comparative Example 1, the oligomer was remarkably sublimated during spinning, and the filaments were bent due to the bent holes, and the density was uneven.

Comparative Example 8 An oligomer was extracted from the structure of Example 2 using a solvent.
PLA having an oligomer content of 0.005% by weight or less
The structure did not show any antibacterial properties with an antibacterial rating of 0.3.

Comparative Example 9 An attempt was made to obtain a structure in the same manner as in Example 2 except that the spinning temperature was set to 180 ° C., but the melt viscosity was increased and loop formation was poor, and the structure could not be obtained. Was.

Comparative Example 10 The structure obtained in the same manner as in Example 2 except that the spinning temperature was 285 ° C. was spun at a high temperature, so that the structure deteriorated remarkably. However, the structure was fragile and collapsed when a load was applied. Finally, various evaluations were impossible.

Comparative Example 11 The procedure of Example 1 was repeated except that the spinning temperature of the polypropylene having a melt flow index of 50 was 210 ° C. and the take-up speed was 1000 mm / min. Under the same spinning conditions as in Example 2, a polypropylene structure was obtained. This polypropylene structure has a good bonding state and an apparent density of 0.08 g /
cc, thickness 20mm, filament is solid round cross section and fineness is 85
It was 00 denier. Table 1 shows other characteristics. The structure of the material outside the present invention does not exhibit antibacterial and antifungal properties and has poor elasticity.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of an apparatus used for a manufacturing method of the present invention.

[Explanation of symbols]

 2 Melting line 3 3D structure 5 Multi-row nozzle 6 Cooling tank 7 Pick-up device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) // D01F 6/92 301 D01F 6/92 301A (72) Inventor Kenji Yoshino 2-chome Katata, Otsu City, Shiga Prefecture No. 1 Toyobo Co., Ltd. Research Laboratory (72) Inventor Mikiya Hayashibara 2-1-1 Katata, Otsu-shi, Shiga Prefecture Toyobo Co., Ltd. Research Laboratory (72) Inventor Tomoyuki Aranaga 2-Cata Katata, Otsu-shi, Shiga Prefecture No. 1-1 Toyobo Co., Ltd. Research Institute (72) Inventor Masanobu Ajioka 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsui Chemicals Co., Ltd. (72) Inventor Shoji Obuchi 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui F-term in Chemical Co., Ltd. (reference) 4L035 AA08 BB32 BB57 DD02 DD03 EE11 EE20 FF02 FF04 HH01 HH05 HH10 4L045 AA05 BA03 BA51 BA58 BA60 CA29 CB09 CB10 CB13 DA02 DA20 DA45 DC02 4L047 AA21 AB07 AB09 AB10 BA08 CA15 CB10 CC03

Claims (5)

[Claims] 1. A three-dimensional structure having a fineness of 300 to 100,000 denier and a filament mainly composed of a thermoplastic polylactic acid resin, which is repeatedly bent and joined at most of the contact portions, The density is 0.005 to 0.2 g / cc, and the oligomer component is contained in the polylactic acid resin in an amount of 0.05 to 0.2 g / cc.
An antibacterial and antifungal polylactic acid structure characterized by containing 1 to 10% by weight. 2. The antibacterial and antifungal polylactic acid structure according to claim 1, wherein the melting point of the polylactic acid resin is 150 ° C. or higher. 3. The antibacterial and antifungal polylactic acid structure according to claim 1, wherein the oligomer component is mainly composed of a lactide, a chain dimer of lactic acid, or a mixture thereof. 4. The antibacterial and antifungal polylactic acid structure according to claim 1, wherein the cross-sectional shape of the filament is a hollow cross section or a modified cross section. 5. An oligomer component comprising 0.01 to 10% by weight.
A melt mainly containing the thermoplastic polylactic acid resin contained therein is discharged downward from a nozzle having a plurality of orifices, and is repeatedly bent in a molten state, and is brought into contact with each other while being joined together, and is sandwiched by a take-off device. A method for producing an antibacterial and fungicidal polylactic acid structure, characterized by cooling with a water.