JP6924320B2 - Resin composition for melt spinning, its manufacturing equipment and its manufacturing method, fiber manufacturing method, and melt spinning equipment - Google Patents

Description

The present invention relates to a resin composition for melt spinning, a method for producing the same, and a method for producing fibers.

The melt spinning method is a technique capable of producing a fiber sheet having fine-diameter fibers easily and with high productivity by discharging a molten liquid of a raw material resin in the presence of a gas flow or an electric field. The applicant has proposed an apparatus for producing fibers by a molten electric field spinning method and a method for producing the same (Patent Document 1).

Patent Document 2 discloses a method for producing fine thermoplastic resin fibers by melt electrospinning a thermoplastic resin yarn having a diameter of 1.0 mm or less. Further, Patent Document 3 discloses a filament composed of a polypropylene resin having a melt mass flow rate of 0.1 to 30 g / 10 min, an olefin-based copolymer rubber, and an olefin-based thermoplastic elastomer composition containing a softening agent. It is disclosed in the same document that this filament is produced by melting a raw material and then stretching it, and that the filament is used for modeling a three-dimensional printer.

JP-A-2017-190533 Japanese Unexamined Patent Publication No. 2007-32146 JP-A-2018-144308

In producing fibers and fiber sheets with high production efficiency by the melt spinning method, a method having improved handleability of raw materials, prevention of thermal deterioration of raw materials, and continuous supply of raw materials is desired. In general, when such a method is adopted, there may be a problem in terms of equipment such as introduction of new equipment or complicated operation of equipment. Further, when a large amount of raw materials are melted and prepared, a large amount of heat energy is required, and it takes time to melt and prepare the raw materials, which may cause thermal deterioration of the raw materials. No study has been made in Patent Documents 1 to 3 regarding solving such a point.

Therefore, the present invention relates to a resin composition for melt spinning, which is a filament having both high handleability and high continuous supply.

The present invention relates to a resin composition for melt spinning.
In one embodiment, the melt-spun resin composition is a filament.
In one embodiment, the filament has a melt viscosity of 250 Pa · s or less at 200 ° C. and a shear rate of 0.1 s- ^1.
In one embodiment, the filament has a tensile strength of 10 MPa or more.

The present invention also relates to a method for producing a resin composition for melt spinning, which is a filament.
In one embodiment, the production method forms a filament of a resin composition having a melt viscosity of 250 Pa · s or less at 200 ° C. and a shear rate of 0.1 s- ^1.
In one embodiment, the manufacturing method cools the filament molded product while transporting it.

Furthermore, the present invention relates to a method for producing a fiber using a melt spinning device.
In one embodiment, the melt spinning apparatus directly communicates with a supply port to which a raw material is supplied, a heating unit that melts the raw material supplied from the supply port without applying kneading force, and the heating unit. It is provided with a nozzle for discharging the molten raw material.
In one embodiment, the production method is a resin composition for melt spinning, which is a filament having a melt viscosity of 250 Pa · s or less and a tensile strength of 10 MPa or more at 200 ° C. and a shear rate of 0.1 s- ^{1 as the raw material.} Use things.
In one embodiment, in the manufacturing method, while supplying the filament from the supply port, the melted raw material is discharged from the nozzle and spun.

According to the present invention, there is provided a resin composition for melt spinning, which is a filament having both high handleability and high continuous supply.

FIG. 1 is a schematic view showing an embodiment of the filament manufacturing apparatus of the present invention. FIG. 2 is a schematic view showing another embodiment of the filament manufacturing apparatus of the present invention. 3A and 3B are schematic cross-sectional views showing still another embodiment of the filament manufacturing apparatus of the present invention. FIG. 4 is a schematic view showing an embodiment of a melt spinning apparatus including the filament manufacturing apparatus shown in FIG. 3 (a). 5 (a) and 5 (b) are enlarged schematic views showing the arrangement positions of the discharge port and the transport portion. FIG. 6 is a schematic perspective view showing an embodiment of the melt spinning apparatus of the present invention. 7 (a) and 7 (b) are schematic cross-sectional views showing an embodiment of a spinning unit in the melt spinning apparatus of the present invention.

Hereinafter, the present invention will be described based on the preferred embodiment with reference to the drawings.
The resin composition is a solid or hollow filament having a predetermined melt viscosity and a predetermined tensile strength.
This resin composition is suitably used for melt spinning applications such as the melt blow method and the melt electric field spinning method as a molten liquid obtained by heating and melting the resin composition. The melt blow method and the molten electric field spinning method are spinning methods particularly suitable for producing ultrafine fibers among the melt spinning methods.

From the viewpoint of achieving a smaller diameter of the spun fiber, the resin composition has a melt viscosity of preferably 250 Pa · s or less, more preferably 150 Pa · s or less at a temperature of 200 ° C. and a shear rate of 0.1 s- ^1. It is preferably 80 Pa · s or less, and particularly preferably 30 Pa · s or less.
Further, from the viewpoint of improving the moldability of the filament and suppressing unintended fracture of the spun fiber, the melt viscosity of the resin composition at ^{a temperature of 200 ° C. and a shear rate of 0.1 s-1 is preferably 0.05 Pa.} -S or more, more preferably 0.1 Pa · s or more, still more preferably 0.5 Pa · s or more.
When the melt viscosity is in such a range, the diameter of the fiber can be reduced when the resin composition is melt-spun.
Further, when the resin composition is subjected to melt spinning, the discharge efficiency of the molten liquid can be increased, and the fiber formation efficiency can be increased.
The melt viscosity of the resin composition can be appropriately changed by, for example, changing the molecular weight of the raw material resin used, adding a plasticizer, a modifier, or the like described later.

The melt viscosity of the resin composition is determined by the temperature of a sample obtained by using a known extruder of the resin composition by the following method using a viscoelasticity measuring device (model number MCR302) manufactured by Anton Pearl Japan Co., Ltd. It can be measured under the conditions of 200 ° C. and a shear rate of 0.1 s- ^1.

<Measurement method of melt viscosity of resin composition>
Specifically, first, the measurement sample is filled in the hole portion of the fluororesin-coated SUS plate having a hole of 100 mm × 100 mm × 1 mm.
Then, using a known heat press device, the filled measurement sample is heat-pressed at a temperature of 180 ° C. at a pressure setting of 0.5 MPa per 300 mm × 300 mm for 1.5 minutes to prepress.
After that, the step of pressurizing for 3 seconds under the above-mentioned pressurizing conditions and releasing the pressurization for 1 second is set as one cycle, and the cycle is repeated four times to bleed the air in the sample.
Subsequently, heat press is performed at a temperature of 180 ° C. and a pressure setting of 20 MPa per 300 mm × 300 mm for 1 minute to perform the main pressurization.
Finally, the temperature is 14 ° C., and the pressure is set to 0.5 MPa per 300 mm × 300 mm for 1 minute to cool.
The press-molded plate obtained by this method is cut into a diameter of 50 mm and a thickness of 1 mm to obtain a circular sample plate. This sample plate is introduced into the viscous elasticity measuring device provided with a disk-disk type measuring jig or a cone-disk type measuring jig having a diameter of 50 mm, the sample plate is melted at a temperature of 200 ° C., and the shear rate is 0. . Measure the melt viscosity under the conditions of 1s ^-1.

The resin composition preferably has a tensile strength of 10 MPa or more, more preferably 12 MPa or more, still more preferably 15 MPa or more, from the viewpoint of improving both the handling property of the filament and the continuous supply property at the time of fiber spinning.
Further, when the filament is wound and stored, the tensile strength of the resin composition is preferably 150 MPa or less, more preferably 120 MPa or less, still more preferably 100 MPa or less, from the viewpoint of improving the take-up property and the storeability. ..
When the tensile strength is in such a range, the resin composition can be easily handled, and can be easily continuously supplied as a raw material for melt spinning, so that the fiber production efficiency can be improved.
The tensile strength of the resin composition can be adjusted, for example, by changing the type of resin used, changing the cooling temperature or speed to change the crystal state of the obtained resin composition, or using a plasticizer or modification described later. It can be appropriately changed by a method such as adding an agent or the like.

From the viewpoint of improving both the handling property of the filament and the continuous supply property at the time of fiber spinning, the resin composition has a breaking strain of preferably 1% or more, more preferably 1.5% or more, still more preferably. It is 2% or more, and particularly preferably 2.5% or more.
The breaking strain of the resin composition is not particularly limited, but is practically 20% or less, preferably 18% or less.
When the breaking strain is in such a range, the resin composition can be easily handled, and can be easily continuously supplied as a raw material for melt spinning, so that the fiber production efficiency can be improved.
The breaking strain of the resin composition can be changed, for example, by changing the type of resin used, changing the cooling temperature or rate, changing the crystal state of the obtained resin composition, or using a plasticizer or modification described later. It can be appropriately changed by a method such as adding an agent or the like.

The tensile strength and breaking strain of the resin composition are measured using a tensile tester (AG-X plus manufactured by Shimadzu Corporation). The test speed is 50 mm / min, the distance between chucks is 80 mm, the test is performed using a resin composition which is a filament with a length of 120 mm, and a tensile test is performed along the filament length direction until fracture occurs. Measure the maximum test force and chuck movement distance. This measurement is performed 3 times.
The tensile strength and breaking strain shall be the arithmetic mean values of the values calculated from each of the three measured values based on the following formula. In the following formula, R is the filament cross-sectional diameter described later.
Tensile strength [MPa] = (maximum test force [N]) / (π × ( filament cross-sectional diameter ^R at the beginning of the tensile test) 2/4)
Breaking strain [%] = (Chuck moving distance [mm] / Chuck distance at the start of tensile test [mm]) x 100

As described above, the resin composition is a filament. The average value R of the filament cross-sectional diameters of the resin composition, that is, the average cross-sectional diameter R in the direction orthogonal to the filament length direction, is a viewpoint of improving both the handling property of the filament and the continuous supply property at the time of fiber spinning. Therefore, it is preferably 1 mm or more, more preferably 1.3 mm or more, and further preferably 1.5 mm or more.
Further, from the viewpoint of ease of melting of the filament, it is preferably 30 mm or less, more preferably 20 mm or less, further preferably 15 mm or less, still more preferably 5 mm or less, and particularly still more preferably 3 mm or less.

A filament is generally an infinite length fiber that has substantially no end, but is broadly interpreted herein in a substantially broader sense. Specifically, the ratio of the length to the average cross-sectional diameter R (filament length / average cross-sectional diameter R of the filament) from the viewpoint of facilitating the molding of the filament into a rod shape and improving the handleability when introduced into the spinning apparatus. However, fibers preferably 20 or more, more preferably 50 or more, still more preferably 100 or more are included in the filaments herein.
Since the filament has a substantially infinite length, there is no upper limit to the ratio, but from the viewpoint of improving the storage stability of the filament, 1,000,000 or less is realistic.

The length of the filament is infinite as described above, but from the viewpoint of improving the storage stability of the filament, the length is preferably 10,000 m or less, more preferably 5000 m or less.
Further, from the viewpoint of facilitating the formation of the filament into a rod shape and improving the handleability when introduced into the spinning apparatus, the filament is preferably 50 mm or more, more preferably 100 mm or more, and is included in the filament in the present specification.
Such filaments can be obtained, for example, by cutting infinite length filaments to a predetermined length.
The filament length can be measured by measuring the winding length or winding diameter, or can be calculated from the measured length or winding diameter.
As described above, when the filament diameter, the filament length, and the ratio of the filament length / cross-sectional average diameter R are in the above ranges, the filament can be more easily handled during storage and spinning. ..

<Measuring method of average cross-sectional diameter of filament>
The average cross-sectional diameter of the filament can be measured as follows. That is, for one filament having a length of more than 50 cm, the length in the direction orthogonal to the length direction of the filament was measured at 10 points along the length direction of the filament at 5 cm intervals using a caliper. The arithmetic mean value of the measured values is taken as the cross-sectional average diameter. When the filament cross section is not a perfect circle, the major axis and the minor axis are measured at each measurement point using a nogisu, and the arithmetic average value of the major axis and the minor axis at each measurement point is used as the measurement value at each measurement point. The arithmetic average value of the measured values of all the measuring points is referred to as the "cross-sectional average diameter of the filament" of the present disclosure.
The standard deviation of the cross-sectional diameter of the filament is one of the indexes showing the uniformity of the cross-sectional diameter of the filament. When measuring the standard deviation of the cross-sectional diameter of the filament, the standard deviation is calculated based on the measured values measured at 10 points by the above method. The smaller the standard deviation, the more uniform the cross-sectional diameter of a single filament.

The resin composition which is a filament preferably contains a thermoplastic resin as a main component thereof. In the present specification, the "main component" means a component having a content ratio of 50% by mass or more in the resin composition.
This thermoplastic resin has a fiber-forming property and a melting point in melt spinning.
A resin having a "melting point" is endothermic due to a phase change from a solid to a liquid before the resin is thermally decomposed when the resin to be measured is heated in the differential scanning calorimetry method. It is a resin that shows a peak.

Examples of such thermoplastic resins include polyolefin resins, polyester resins, polyamide resins, vinyl polymers, acrylic polymers, nylon polymers, polyvinyl acetate, polyvinyl acetate-ethylene copolymers and the like.
Examples of the polyolefin resin include polyethylene, polypropylene (PP), ethylene-α-olefin copolymer, ethylene-propylene copolymer and the like.
Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, liquid crystal polymer, and polylactic acid-based resin.
Examples of the polylactic acid-based resin include polylactic acid (PLA) and a lactic acid-hydroxycarboxylic acid copolymer.
Examples of the vinyl polymer include polyvinyl chloride, polyvinylidene chloride, polystyrene and the like.
Examples of the acrylic polymer include polyacrylic acid, polyacrylic acid ester, polymethacrylic acid, and polymethacrylic acid ester.
Examples of the nylon polymer include nylon 6, nylon 66 and the like.
As these resins, commercially available products may be used, commercially available products may be subjected to post-treatment such as hydrolysis, or synthetic products may be used. These resins may be used alone or in combination of two or more.

Of these, from the viewpoint of increasing mechanical properties such as strength and flexibility when made into a filament, and from the viewpoint of increasing the versatility of the use of the fiber when the fiber is manufactured using the filament. The resin composition preferably contains one or more selected from polyolefin resins and polyester resins, and more preferably contains one or more selected from PP and polylactic acid-based resins. The lactic acid constituting the repeating unit of the polylactic acid-based resin may be either an L-form or a D-form optical isomer.

The content of the thermoplastic resin contained in the resin composition is preferably 70 parts by mass or more with respect to 100 parts by mass of the resin composition from the viewpoint of enabling the addition of additives and improving the fiber forming property. It is more preferably 75 parts by mass or more, further preferably 80 parts by mass or more, and particularly preferably 95 parts by mass or more.
Further, from the viewpoint of increasing the versatility of the fiber, the content of the thermoplastic resin with respect to 100 parts by mass of the resin composition is preferably 100 parts by mass or less.

<Method of measuring the content of thermoplastic resin in the resin composition>
The content of the thermoplastic resin in the resin composition can be measured by the following method. Specifically, the resin composition is subjected to various analyzes such as NMR (nuclear magnetic resonance) analysis and IR (infrared spectroscopy) analysis, and the molecular skeleton is based on the position of each signal and spectrum obtained by these analyzes. The structure and the functional group structure at the end of the molecular structure are identified. Thereby, the type of the resin contained is identified, and the amount of the thermoplastic resin contained in the various resin composition parts is calculated from the strength of the measured value showing the molecular structure corresponding to the various thermoplastic resins. Then, the content of the thermoplastic resin contained in the resin composition can be measured by summing the calculated values.

When the resin composition contains a thermoplastic resin, it is preferable to include a PP resin as the thermoplastic resin because it has high flexibility and high chemical resistance. Further, since it is highly versatile and exhibits biodegradability, it is preferable to include a polylactic acid-based resin as the thermoplastic resin. From the viewpoint of exhibiting high flexibility and chemical resistance, or high versatility and biodegradability, it is more preferable that the resin composition is mainly composed of PP resin or polylactic acid-based resin.

It can be specified by the following method that the resin composition contains a PP resin or a polylactic acid-based resin. The resin composition to be measured is subjected to various analyzes such as NMR analysis and IR analysis in the same manner as described above to identify the structure of the molecular skeleton and the functional group structure at the end of the molecular structure. This identifies whether the constituent resin of the resin composition is a single type or a plurality of types, and that the resin composition contains a PP resin or a polylactic acid-based resin.

When a PP resin is contained as the thermoplastic resin constituting the resin composition, the weight average molecular weight thereof is preferably 150,000 g / mol or less, more preferably 100,000 g / mol or less, from the viewpoint of achieving a smaller diameter of the fiber at the time of spinning. More preferably, it is 80,000 g / mol or less.
When a PP resin is contained as the thermoplastic resin constituting the resin composition, the weight average molecular weight thereof is preferably 1000 g / g from the viewpoint of both improving the moldability of the filament and suppressing unintended breakage of the spun fiber. It is mol or more, more preferably 5000 g / mol or more, still more preferably 10000 g / mol or more.

When a polylactic acid-based resin is contained as the thermoplastic resin constituting the resin composition, the weight average molecular weight thereof is preferably 150,000 g / mol or less, more preferably 100,000 g / mol or less, from the viewpoint of reducing the diameter of the fiber during spinning. , More preferably 80,000 g / mol or less, and even more preferably 50,000 g / mol or less.
When a polylactic acid-based resin is contained as the thermoplastic resin constituting the resin composition, the weight average molecular weight thereof is preferably from the viewpoint of improving the moldability of the filament and suppressing unintended breakage of the spun fiber. It is 1000 g / mol or more, more preferably 5000 g / mol or more, still more preferably 10000 g / mol or more.

When the thermoplastic resin contains a polylactic acid-based resin, the weight average molecular weight of the polylactic acid-based resin can be measured by using gel permeation chromatography. When measuring the polystyrene-equivalent weight average molecular weight using gel permeation chromatography, as a pretreatment, the thermoplastic resin to be measured was dissolved in an eluent described later at a predetermined concentration to remove undissolved impurities. Prepare a lysate. Then, using this solution as a measurement sample, the molecular weight distribution is measured according to the following conditions by gel permeation chromatography.
Similarly, as a polystyrene standard sample, a polystyrene sample having a known weight average molecular weight and different weight average molecular weights (monodisperse polystyrene manufactured by Toso Co., Ltd. (model numbers: F450, F288, F128, F80, F40, F20, F10, A molecular weight calibration curve can be prepared in advance using F4, F1, A5000, A2500, A1000, A500 and A300), and the weight average molecular weight in terms of polystyrene can be measured by comparing the calibration curve with the result of the measurement sample. can.

In this measurement method, those having a large molecular weight are eluted quickly based on the principle of gel permeation chromatography. Therefore, the components, mass and time eluted when the measurement sample is passed through the column are measured, and these results are obtained. Can be compared with the calibration curve to calculate the molecular weight distribution of the measurement sample.

<Gel permeation chromatography conditions>
-Measuring device: HLC-8220GPC (manufactured by Tosoh Corporation)
-Column: GMHHR-H + GMHHR-H (manufactured by Tosoh Corporation)
-Eluent: 1 mmol chloroform DM20 (manufactured by Kao Corporation) / CHCl3
-Eluent flow rate: 1.0 mL / min
-Column temperature: 40 ° C
・ Detector: RI
-Sample concentration: 0.1% by volume (chloroform solution)
・ Sample injection volume: 100 mL

When a plurality of resin types are contained in the resin composition, the types of the thermoplastic resin contained are identified by various analyzes such as the above-mentioned NMR analysis and IR analysis. Next, the polylactic acid-based resin is extracted using a solvent in which the polylactic acid resin is dissolved and the other resin is insoluble, or a solvent in which the polylactic acid-based resin is not dissolved and the other resin is dissolved. Then, the weight average molecular weight of the extracted polylactic acid-based resin is measured by the above-mentioned method.
When the thermoplastic resin contains a polypropylene resin, the weight average molecular weight is measured according to the above-mentioned measuring method using an orthodichlorobenzene as an eluent and a solution of a polypropylene resin dissolved at a dissolution temperature of 140 to 150 ° C. can do.

The resin composition is one or more additives selected from elastomers, plasticizers, modifiers, decomposition inhibitors and charge modifiers, depending on the application of melt spinning, from the viewpoint of increasing the production efficiency of fibers. May include. These additives can be used alone or in combination of two or more.
The elastomer improves the elasticity of the resin composition and enhances the toughness. As the elastomer, for example, a polyolefin-based elastomer, a polystyrene-based elastomer, a polyester-based elastomer, a polyurethane-based elastomer, or the like can be used.

The content and molecular structure of the additive in the resin composition can be identified by specifying the molecular structure by known techniques such as NMR, various chromatography, IR analysis, and combinations thereof. In addition, the content of the additive can be measured by the above-mentioned measuring means by the intensity of the measured value of the portion showing the above-mentioned molecular structure.
As the additive, the additive is extracted and concentrated by Soxhlet with various solvents from the fiber to be measured, and the concentrated solution is subjected to pyrolysis gas chromatography (GC-MS) analysis. The compound can be identified from the mass spectrum obtained here, and the content can be calculated.

The plasticizer is modified so as to increase the flexibility of the resin composition, change the glass transition temperature (Tg), or increase the fluidity of the melt of the resin composition.
Examples of the plasticizer include polyethylene glycol (PEG), glycerin, glycerin fatty acid ester, glycerin acetate, phosphoric acid ester, cellulose derivative (hydroxypropyl cellulose: HPC and methyl cellulose: MC), lactone, carbamate ester, phthalic acid and the like. Can be used.

The modifier is a modifier that enhances the flexibility of the resin composition and enhances the fluidity of the resin composition when it is made into a molten liquid.
As the modifier, for example, a low crystalline polyolefin such as a low stereoregular polyolefin (molding processing modifier L-MODU manufactured by Idemitsu Kosan Co., Ltd.) can be used.

The decomposition inhibitor suppresses the decomposition of the resin composition and the decrease in molecular weight when the melted liquid of the resin composition is subjected to melt spinning such as a melt blow method and a molten electric field spinning method.
Examples of the decomposition inhibitor include carbodiimide compounds such as monocarbodiimide compounds and polycarbodiimide compounds. These additives can be used alone or in combination of two or more.

Examples of the monocarbodiimide compound include an aromatic monocarbodiimide compound, an alicyclic monocarbodiimide compound, and an aliphatic monocarbodiimide compound.
Examples of aromatic monocarbodiimide compounds include diphenylcarbodiimide, di-2,6-dimethylphenylcarbodiimide, di-2,6-diethylphenylcarbodiimide, di-2,6-diisopropylphenylcarbodiimide, and di-2,6-di-tert. -Butylphenylcarbodiimide, di-o-tolylcarbodiimide, di-p-tolylcarbodiimide, di-2,4,6-trimethylphenylcarbodiimide, di-2,4,6-triisopropylphenylcarbodiimide, and di-2,4 , 6-Triisobutylphenylcarbodiimide and the like.
Examples of the alicyclic monocarbodiimide compound include di-cyclohexylcarbodiimide and di-cyclohexylmethanecarbodiimide.
Examples of the aliphatic monocarbodiimide compound include di-isopropylcarbodiimide and di-octadecylcarbodiimide.
Examples of the polycarbodiimide compound include aromatic polycarbodiimide compounds and alicyclic polycarbodiimide compounds.
Aromatic polycarbodiimide compounds include poly (4,4'-diphenylmethanecarbodiimide), poly (p-phenylene carbodiimide), poly (m-phenylene carbodiimide), poly (diisopropylphenylcarbodiimide), and poly (triisopropylphenylcarbodiimide). And so on.
Examples of the alicyclic polycarbodiimide compound include poly (dicyclohexylmethanecarbodiimide).

The charge adjuster modifies the melt of the resin composition so as to develop a high charge amount when the melt is subjected to the molten electric field spinning method.
Examples of the charge regulator include salts of higher fatty acids and metals, sulfate esters, sulfonates and the like.
The higher fatty acid typically has 12 or more and 24 or less carbon atoms. The fatty acid moiety may have an unsaturated bond. Examples of the metal salt include Zn, Mg and Li.
Examples of the salt of the higher fatty acid and the metal include Zn stearate, Mg stearate, Li stearate, Zn laurate, Zn ricinoleic acid and the like.
Examples of the sulfate ester salt include alkyl sulfates and alkyl ether sulfates.
Examples of the sulfonate include alkyl sulfonate, alkylbenzene sulfonate, alkylnaphthalene sulfonate, olefin sulfonate, N-alkyl-N-acylaminoalkyl sulfonate, and alkane sulfonate.
Examples of the N-alkyl-N-acylaminoalkyl sulfonate include, but are not limited to, sodium N-stearoylmethyl taurine.
These additives can be used alone or in combination of two or more.

From the viewpoint of increasing the production efficiency of the small-diameter fibers, the content of the additive in the resin composition is preferably 0 parts by mass or more with respect to 100 parts by mass of the resin composition.
From the viewpoint of improving the strength of the small-diameter fibers, the content of the additive in the resin composition is preferably 40 parts by mass or less, preferably 30 parts by mass or less, based on 100 parts by mass of the resin composition. More preferably, it is more preferably 20 parts by mass or less, and particularly preferably 15 parts by mass or less.

According to the above-mentioned resin composition, since it has a predetermined melt viscosity, when it is used as a melt for melt spinning, the discharge amount and discharge speed of the melt to the outside can be increased, and the melt can be discharged. Since the drawing efficiency of the fiber can be increased, fine-diameter fibers can be produced with high production efficiency.
Further, since the resin composition is a filament having a predetermined tensile strength, unintentional breakage, cracking, buckling, and fracture are reduced when the filament is stored or when the filament is subjected to melt spinning. It is possible to improve the storage stability and handleability of the resin composition which is a filament.
According to a preferred embodiment of the resin composition which is a filament, the flexibility is high, the handling at the time of storage and the time of spinning can be further facilitated, and the production efficiency of the fiber can be further improved.
In addition to this, even when a polylactic acid-based resin, which was difficult to apply to melt spinning with conventional techniques, is prevented from deteriorating the raw material due to heat and hydrolysis during melting. It is possible to efficiently produce fibers with a small diameter.
Further, by using the resin composition as a filament, a fiber or a fiber sheet can be produced by a melt spinning method by a simple operation of melting only a part of a filament raw material. As a result, unlike the case of melt-spinning while preparing a molten liquid from a powder or pellet-shaped resin raw material using an extruder or the like, it is possible to reduce the size and labor of the equipment without introducing a large-scale equipment. Can be done. In addition to this, since only a part of the resin composition is melted when it is subjected to melt spinning, it is not necessary to melt the entire resin composition to be subjected to fiber formation. Therefore, thermal deterioration of the raw material can be prevented.

Next, a method for producing the resin composition which is a filament will be described.
This manufacturing method can be suitably carried out by the filament manufacturing apparatus 10 shown in FIGS. 1 to 5. The manufacturing apparatus 10 shown in FIG. 1 is roughly classified into an extrusion molding unit 20 and a transport unit 30.

The extrusion molding unit 20 includes a cylinder 21, a discharge unit 22, and a hopper 29 for supplying the resin composition.
In the cylinder 21, the resin composition supplied from the hopper 29 can be heated and melted in the cylinder 21 to obtain a melt L of the resin composition.
The molten liquid can be supplied by pushing out the molten liquid in the direction of the discharge portion 22, which will be described later, by a screw (not shown) provided in the cylinder 21.

The discharge unit 22 is a member that extrudes the molten liquid of the resin composition into a filament shape, and includes a discharge base portion 23 and a discharge port 24.
The cylinder 21, the discharge base 23, and the discharge port 24 communicate with each other, and the molten liquid in the cylinder 21 can be continuously pushed out from the discharge port 24 via the inside of the discharge base 23.
A gear pump (not shown) is installed in the discharge base 23 so that the molten liquid of the resin composition can be discharged in a fixed amount.

The transport unit 30 transports the filament-shaped molded product S extruded from the discharge port 24 to the next step.
The transport unit 30 is provided at a position substantially opposite to the discharge port 24, and is composed of one or more of a conveyor and a roll.
The transport unit 30 shown in FIGS. 1 and 2 is in the form of a belt conveyor in which an endless belt is arranged so as to orbit in one direction, and receives the molded product S directly without interposing other members. It can be transported in direct contact with the belt conveyor.
The transport units 30 shown in FIGS. 3 (a) and 3 (b) and FIG. 4 are in the form of transport rolls 36 and 37.

One of the features of the manufacturing apparatus 10 is that the distance between the discharge port 24 in the extrusion molding unit 20 and the transport unit 30 is within a predetermined range, and the diameter of the discharge port 24 is within a predetermined range.
Since the manufacturing apparatus 10 has the above-described configuration, even when a resin composition having a relatively low melt viscosity and high fluidity of the molten liquid is used as the resin composition to be introduced into the present manufacturing apparatus, it is possible to use the resin composition from the discharge port 24. When extrusion molding into a filament, dripping from the discharge port 24 prevents the discharged molded product from unintentionally adhering to members other than the transport portion 30, and stretches the molded product into the intended shape. be able to. As a result, uniform and continuous filaments can be formed.

Specifically, the distance D1 (see FIGS. 5A and 5B) between the discharge port 24 in the extrusion molding section 20 and the transport section 30 suppresses the molded product from being stretched into an unintended shape. From the viewpoint of forming the obtained filament into a uniform shape, it is preferably 50 mm or less, more preferably 30 mm or less, and further preferably 15 mm or less.
Further, from the viewpoint of stabilizing the shape of the molten liquid extruded from the discharge port and enhancing the uniformity of the shape of the obtained filament, the distance D1 is preferably 1 mm or more, more preferably 3 mm or more, still more preferably 5 mm or more. ..
The distance D1 between the discharge port 24 and the transport unit 30 is the shortest distance from the end of the discharge port 24 to the intersection of the virtual extension line extending along the axial direction of the discharge port 24 and the surface of the transport unit 30.
Further, as shown in FIG. 3B, when the molded product S discharged from the discharge port 24 is directly immersed in the liquid W without passing through other members, the distance D1 is the liquid between the discharge port 24 and the liquid W. The shortest distance to the surface.

Further, the diameter of the discharge port 24 is preferably 1 mm or more, more preferably 3 mm or more, still more preferably, from the viewpoint of appropriately stretching the filament, stabilizing the production, and facilitating the acquisition of the filament having a desired diameter. Is 5 mm or more.
Further, from the viewpoint of uniformly extruding the molten resin and achieving the morphological maintenance of the molten resin, the diameter of the discharge port 24 is preferably 50 mm or less, more preferably 40 mm or less, still more preferably 30 mm or less.
The shape of the discharge port 24 is preferably a perfect circle.
By making the manufacturing apparatus such a size, it is possible to form a filament of a resin composition having both high handleability and high continuous supply.

The filament-shaped molded product S extruded from the discharge port may not be sufficiently cooled and solidified after extrusion molding. From the viewpoint of reliably maintaining the filament shape of the extruded molded product S, it is preferable to provide means for cooling the molded product S while transporting it to the unidirectional MD.
As the cooling means, for example, the transport path of the transport unit 30 may be formed long along the transport direction to allow natural cooling, and the transport unit 30 is in contact with the refrigerant or the cooling device (not shown). Therefore, the transport unit 30 itself may be cooled, or the cooling unit 40 may be further provided on the downstream side of the transport unit 30.
When the cooling unit 40 is provided, the cooling unit 40 contains a conveyor and a cooling roll that are cooled in contact with a refrigerant or a cooling device (not shown), a cooling gas supply unit that can blow a cooling gas flow, and a cooling gas. It is also preferable that the inside thereof is composed of at least one gas tank through which the molded product S can pass, and at least one liquid tank in which the cooling liquid is housed and the molded product S can come into contact with the liquid.
As the cooling gas, for example, air can be used to air-cool the molded product S.
As the cooling liquid, water is preferably used from the viewpoint of not affecting the composition of the molded product S.
Of these, from the viewpoint of increasing the cooling efficiency of the molded product, it is preferable to use a liquid tank, and it is more preferable to use a liquid tank containing water.

The manufacturing apparatus 10 shown in FIG. 1 includes a cooling unit 40 having a liquid tank 41 and a transport roll 42 on the downstream side of the transport unit 30 in the transport direction.
The molded product S discharged from the discharge port 24, extruded, and transported by the transport unit 30 and the transport roll 42 can be cooled by bringing the molded product S into contact with the liquid W in the liquid tank 41. ..
Further, the manufacturing apparatus 10 shown in FIG. 2 is provided with a cooling gas supply unit 45 above the transport unit 30 and downstream in the transport direction, and can bring the gas flow A into contact with the molded product S to be air-cooled. ..

Further, in the manufacturing apparatus 10 shown in FIGS. 3A and 4, the transport roll 36 constituting the transport unit 30 is arranged in a state of being partially immersed in the liquid W contained in the liquid tank 41.
In the present embodiment, the molded product S discharged from the discharge port 24 is directly received on the peripheral surface of the transport roll 36 that is not immersed in the liquid W, and the molded product S adhering to the peripheral surface is transferred by the rotation of the transport roll 36. , Contact the liquid W to cool.
This makes it easier to maintain the shape of the molded product S at the time of molding, and makes it possible to more easily produce a filament having high storage stability and handleability.

Further, in the manufacturing apparatus 10 shown in FIG. 3B, the transport rolls 36 constituting the transport unit 30 are arranged in a state of being completely immersed in the liquid W contained in the liquid tank 41.
In the present embodiment, the molded product S discharged from the discharge port 24 is brought into direct contact with the liquid W to be cooled, and the cooled molded product S is adhered to the peripheral surface of the transport roll 36 and transported.
As described above, the transport unit 30 and the cooling unit 40 may be arranged separately or integrally.

From the viewpoint of increasing the cooling efficiency of the molded product S to form a filament of the resin composition having both high handleability and high continuous supply property, the resin composition with respect to the temperature (cooling temperature) in the transport unit 30 or the cooling unit 40. The ratio of the melt temperature (melt temperature / cooling temperature) of the above is preferably 1.2 times or more, more preferably 1.3 times or more, still more preferably 1.4 times or more in terms of absolute temperature.
Further, the ratio of the temperature of the melt of the resin composition to the cooling temperature (melt temperature / cooling temperature) is 2.1 times or less, preferably 1.9 times or less, more preferably 1. It is realistic to make it 7 times or less.
The melt temperature of the resin composition is the temperature of the melt at the discharge port 24.
Such a temperature ratio range makes the degree of crystallization of the resin depending on the cooling rate appropriate, and can suppress the occurrence of voids and cracks in the filament, and is flexible and applicable to the melt spinning method. It is particularly advantageous in obtaining a filament having both strength and strength.

From the viewpoint of increasing the cooling efficiency of the molded product S and forming a filament having both flexibility and strength, the cooling temperature is preferably −40 ° C. or higher, more preferably 0 ° C. or higher, still more preferably 5 ° C. or higher. Is.
The upper limit of the cooling temperature can be appropriately changed according to the resin to be used and the desired physical properties, but when water is used for cooling the molded product, the cooling temperature is preferably 90 ° C. or lower from a practical point of view. It is more preferably 80 ° C. or lower, still more preferably 70 ° C. or lower.
From the same viewpoint, it is also preferable that the cooling unit 40 is configured to cool the molded product S by using a gas or liquid having the above-mentioned temperature range.

The method for producing the resin composition which is a filament is as follows.
First, a resin composition having a melt viscosity of 250 Pa · s or less at 200 ° C. and a shear rate of 0.1 s- ¹ is supplied into the cylinder 21 of the extrusion molding unit 20 and heated and melted, and the melt L of the resin composition is melted. And.
Next, the molten liquid is supplied toward the discharge port 24, and the melt liquid is continuously extruded from the discharge port 24 in the form of a filament to form a filament-shaped molded product S.
Subsequently, the molded product S is directly received by the transport unit 30, and is cooled while being transported downstream.

From the viewpoint of applying an appropriate external force before the molded product S is sufficiently cooled and solidified to facilitate the formation of filaments having a uniform surface condition and shape, the molded product with respect to the extrusion speed V1 of the molten liquid from the discharge port 24. The ratio (V2 / V1) of the transport speed V2 of S is preferably 1 or more, more preferably 3 or more, still more preferably 5 or more, still more preferably 7 or more.
Further, from the viewpoint of suppressing the shape change due to excessive stretching, V2 / V1 is preferably 50 or less, more preferably 35 or less, still more preferably 25 or less.

From the same viewpoint, the extrusion speed V1 of the molten liquid from the discharge port 24 is preferably 0.1 m / min or more, more preferably 0.15 m / min or more, and further preferably 0.2 m / min or more.
From the viewpoint of suppressing the shape change due to excessive stretching, the extrusion speed V1 of the molten liquid from the discharge port 24 is preferably 20 m / min or less, more preferably 10 m / min or less, still more preferably 5 m / min or less.
The extrusion speed of the molten liquid from the discharge port 24 can be appropriately changed by adjusting, for example, the supply speed of the molten liquid from the cylinder 21.

From the same viewpoint, the transport speed V2 of the molded product S is preferably 0.2 m / min or more, more preferably 1.0 m / min or more, still more preferably 1.5 m / min or more, and particularly preferably 2 or more. be.
From the viewpoint of suppressing the shape change due to excessive stretching, the transport speed V2 of the molded product S is preferably 200 m / min or less, more preferably 100 m / min or less, still more preferably 50 m / min or less, and particularly preferably 35 m / min or less. It is as follows.
The transport speed of the molded product S is appropriately adjusted by, for example, adjusting the moving speed of the conveyor in the transport unit 30 or the rotation speed of the roll, or adjusting the winding speed of the filament in the winding unit 50 described later. Can be changed.

When the extruded molded product S is cooled while being transported to the one-way MD, as described above, the molded product S may be naturally cooled while being transported by the transport unit 30, and the molded product S is transported by the transport unit 30. While doing so, the molded product S may be brought into contact with a gas or liquid to be cooled. Alternatively, the molded product S may be cooled while being transported in contact with the cooled transport unit 30, or a cooling unit 40 may be further arranged to cool the molded product S while passing it through the cooling unit 40. You may.

Through the above steps, a resin composition F (hereinafter, also simply referred to as “filament F”) which is a filament can be obtained.

The obtained filament F can be wound by the winding unit 50 and stored in the form of a wound body in which the filament F is wound, for example, as shown in FIGS. 1 to 3.
This wound body can be used to continuously or intermittently supply the raw material using the filament as a raw material in the process of producing ultrafine fibers described later.
Instead, as shown in FIG. 4, as an embodiment of the melt spinning apparatus 100 provided with the above-mentioned manufacturing apparatus 10, the filament F produced by the manufacturing apparatus 10 is directly supplied to the melt spinning apparatus 100 to produce fibers. You may. Details of the melt spinning apparatus 100 will be described later.

In any case, the resin composition which is this filament can be used as it is as a raw material when producing fibers by the melt spinning method, so that thermal deterioration of the raw material at the time of melting is reduced and equipment is provided. It can be applied to existing equipment without causing problems in terms of equipment such as expansion of the equipment.
Further, since the resin composition which is a filament has both flexibility and strength, it reduces unintentional breakage, cracking, buckling, and breakage during storage and melt spinning, and has high handleability. Become.
Further, since the filament produced by the above-mentioned suitable production method is formed by the molten liquid continuously extruded from the discharge port 24, one continuous uniform filament can be produced. As a result, when the fiber is produced using the melt spinning apparatus 100 described later using the filament as a raw material, the raw material can be continuously and stably supplied, and the fiber can be produced stably.

Subsequently, the melt spinning apparatus 100 will be described with reference to FIGS. 4 and 6. The melt spinning device 100 can be suitably used when producing fibers by a melt spinning method, particularly a melt blowing method or a molten electrospinning method. The melt blow method and the molten electric field spinning method are spinning methods particularly suitable for producing ultrafine fibers among the melt spinning methods.
The melt spinning device 100 may be a stationary type that is preferably used when placed on a floor, a shelf, a desk, or the like, has dimensions that can be manually gripped, and is suitable for being manually gripped. It may be a handy type used for.

The melt spinning apparatus 100 shown in FIG. 4 is directly connected to the supply port 110 to which the raw material F is supplied, the heating unit 120 for melting the raw material F supplied from the supply port 110 without applying kneading force, and the heating unit 120. It is provided with a nozzle 130 that communicates and discharges the molten raw material.
The raw material F supplied in the melt spinning apparatus 100 is preferably a raw material containing a thermoplastic resin, and in particular, the resin composition F which is the filament described above is preferably used.
In addition to this, at least the gas flow injection unit 140 for transporting the raw material F discharged from the nozzle 130 to the gas flow and the electrode 160 for forming an electric field for charging the raw material F discharged from the nozzle 130. It is more preferable to have one.

The melt spinning apparatus 100 includes a supply port 110 to which the raw material F is supplied.
The melt spinning apparatus 100 shown in FIG. 4 is provided with a drive unit 111 having an electric motor (not shown) such as a stepping motor in the vicinity of the supply port 110, and supplies the raw material F by the rotation of the electric motor. It can be continuously supplied to the 110 side at a predetermined speed.
The electric motor in the drive unit 111 is connected to the gear 113, which is a spur gear, via a shaft 112, so that the rotation of the electric motor can be transmitted to the gear 113.
A bearing 115 that can be rotated by the rotation of the gear 113 is provided on the side facing the gear 113, and is arranged in a state in which the axial direction of the gear 113 and the axial direction of the bearing 115 are aligned with each other.
By supplying the raw material F between the gear 113 and the bearing 115, the raw material F is conveyed in the unidirectional MD along the rotation direction of the gear 113 and supplied to the supply port 110.
The drive unit 111 is fixed and supported by a support member (not shown) provided on the supply port 110 or the floor or the like.

The melt spinning device 100 includes a heating unit 120 that melts the raw material F supplied from the supply port 110.
The heating unit 120 communicates with the supply port 110. The heating unit 120 is heated by a heating means (not shown) such as a heater, and by supplying the raw material F into the heating unit 120, a molten liquid obtained by melting the raw material F without applying kneading force is obtained. be able to.
"Without applying kneading force" means that no shearing force is applied to the raw material to be melted. That is, the heating unit 120 does not have a member or means for applying a shearing force to the raw material, such as a screw or a stirring blade, inside the heating unit 120.
The molten liquid melted in the heating unit 120 moves to the nozzle 130 side while being pushed out according to the supply speed of the raw material F supplied from the supply port 110.

The heating temperature in the heating unit 120 can be appropriately changed according to the physical properties of the supplied raw material F, but is preferably a temperature equal to or higher than the solidification temperature of the raw material.
For example, when PP (melting point: 160 ° C.) is contained as a raw material, the heating temperature in the heating unit 120 is from the viewpoint of surely melting the raw material to obtain a uniform molten liquid and facilitating the feeding of the molten liquid. It is preferably 180 ° C. or higher, more preferably 190 ° C. or higher.
Further, the heating temperature in the heating unit 120 when PP is used is preferably 280 ° C. or lower, more preferably 260 ° C. or lower, from the viewpoint of suppressing thermal deterioration of the raw material.
Further, for example, when PLA (melting point: 160 ° C.) is included as the raw material, the heating temperature in the heating unit 120 ensures that the raw material is melted to obtain a uniform molten liquid, and facilitates the feeding of the molten liquid. From this point of view, it is preferably 170 ° C. or higher, more preferably 180 ° C. or higher.
The heating temperature in the heating unit 120 when PLA is contained is preferably 280 ° C. or lower, more preferably 260 ° C. or lower, from the viewpoint of suppressing thermal deterioration of the raw material.

The melt spinning apparatus 100 has a hollow nozzle 130 that directly communicates with the heating unit 120 and discharges the molten raw material, and a gas flow injection unit 140 for transporting the molten raw material discharged from the nozzle 130 to a gas flow. I have.
The melt spinning apparatus 100 shown in FIGS. 4 and 6 is in the form of a spinning unit 200 including a nozzle 130 and a gas flow injection unit 140. Further, it is also preferable that the upper part of the spinning unit 200 is provided with a gas flow generating unit 150 that supplies a heated gas flow to the gas flow injection unit 140.

7 (a) and 7 (b) schematically show a cross section of the spinning unit 200 in the melt spinning apparatus 100.
The spinning unit 200 shown in FIG. 7A is preferably used in the melt blowing method among the melt spinning methods.
The nozzle 130 shown in FIG. 7A is arranged in the central region of the spinning unit and directly communicates with the heating unit 120. That is, the supply port 110, the heating unit 120, and the nozzle 130 are all in direct communication with each other.
The nozzle 130 can discharge the molten liquid of the raw material melted in the heating unit 120 from the tip of the nozzle 130 to the outside via the resin supply path 131 communicating with the heating unit 120 and the nozzle 130.
Since the molten liquid discharged from the nozzle 130 is discharged so as to be extruded according to the supply speed of the raw material F supplied from the supply port 110, the discharge amount of the molten liquid appropriately changes the supply speed of the raw material. It can be adjusted as appropriate. That is, if the supply speed of the raw material F supplied from the supply port 110 becomes slower, the discharge amount of the molten liquid from the nozzle 130 decreases, and instead, the supply speed of the raw material F supplied from the supply port 110 increases. The faster the speed, the larger the discharge amount of the molten liquid from the nozzle 130.

A known collection means (not shown) such as a net conveyor or a collection screen is provided at a position facing the nozzle 130, and the discharged molten liquid is collected in a fibrous solidified state. It can be deposited on the means and collected.

Further, one or more gas flow injection units 140 shown in FIG. 7A are arranged on the outside with reference to the position of the nozzle 130 when the spinning unit 200 is viewed from the front.
The gas flow injection unit 140 is configured to be able to inject a heated gas flow from the rear end side to the front end side of the nozzle 130.
The gas flow injection unit 140 is connected to a gas flow generation unit 150 that supplies a heated gas flow to the gas flow injection unit 140, so that the gas flow can be supplied to the gas flow injection units 140 and 140, respectively. ing. From the viewpoint of convenience, for example, an air flow can be used as the gas flow.

On the other hand, the spinning unit 200 shown in FIG. 7B is preferably used in the molten electric field spinning method among the melt spinning methods.
The spinning unit 200 shown in FIG. 7B includes a nozzle 130 and a gas flow injection unit 140, similarly to the spinning unit 200 shown in FIG. 7A.
Regarding the present embodiment, the parts different from the above-described embodiment will be mainly described, and the above-mentioned description of the embodiment will be appropriately applied to the parts not particularly described.

The spinning unit 200 shown in FIG. 7B includes an electrode 160 for charging the nozzle 130, generating an electric field with the nozzle 130, and charging the raw material F.
The electrode 160 in this embodiment is made of a conductive material such as metal, and is electrically connected to a high voltage generator 162 that applies a voltage to the electrode 160. The nozzle 130 is also made of a conductive material such as metal.

The shape and arrangement of the electrode 160 can be appropriately changed as long as an electric field can be formed between the electrode 160 and the nozzle 130.
In the embodiment shown in the figure, the electrode 160 has a substantially bowl shape arranged so as to surround the nozzle 130, and the nozzle 130 and the electrode 160 are separated from each other. The surface of the electrode 160 facing the nozzle 130 is formed in a concave curved surface.
For convenience of explanation, in the following description, the surface of the electrode 160 facing the nozzle 130 is also referred to as a "concave curved surface 161". The electrode 160 has an opening end on the tip end side of the nozzle 130, and the planar shape of the opening end is a circular shape such as a perfect circle or an ellipse. The electrode 160 further includes a high voltage generator 162, and the electrode 160 and the high voltage generator 162 are connected to each other, and a positive or negative voltage is applied by the device.

Further, as shown in FIG. 7B, it is also preferable that the spinning unit 200 includes an electrically insulating wall portion 165 arranged at least on a concave curved surface 161 which is a surface of the electrode 160 facing the nozzle 130. As a result, electric discharge between the nozzle 130 and the electrode 160 can be prevented, and the spinning of the fiber can be stably performed.
The wall portion 165 is preferably composed of, for example, an insulator such as a ceramic material or a resin-based material.
The constituent material of the gas flow injection unit 140 is not particularly limited, but it is preferably selected in consideration of the chargeability of the nozzle 130, and for example, the same material as the wall portion 165 can be used.

The spinning unit 200 shown in FIGS. 6 and 7B has a collecting means (not shown) in which a collecting electrode made of a conductive material such as metal is arranged at a position facing the nozzle 130. You may use it.
The collection electrode is preferably grounded or connected to a high voltage generator to which a voltage is applied. In this case, it is also preferable that a voltage different from the voltage applied to the nozzle 130 is applied to the collecting electrode.
Further, the collecting means may have a carrying means such as a belt conveyor arranged between the nozzle 130 and the collecting electrode. The fibers collected after spinning can be transported to a downstream process by a transport means.

Hereinafter, a method for producing fibers by the melt spinning method using the melt spinning apparatus 100 will be described.
In the production of fibers, a resin composition for melt spinning (that is, a filament having a melt viscosity of 250 Pa · s or less and a tensile strength of 10 MPa or more as a raw material F at 200 ° C. and a shear rate of 0.1 s- ^{1) (that is,} "Filament F") can be preferably used.

When the melt blow method is adopted as the melt spinning method, first, the filament F is supplied from the supply port 110, and the filament F is heated in the heating unit 120 to obtain a molten liquid. The molten liquid moves so as to be pushed out toward the nozzle 130 according to the speed at which the filament F is supplied from the supply port 110.

Next, the gas flow heated from the gas flow generation unit 150 is supplied to the gas flow injection unit 140, and the molten filament F, that is, the molten liquid of the filament F is injected in a state where the gas flow is injected from the gas flow injection unit 140. Is discharged from the nozzle 130 and spun. As a result, the molten liquid can be drawn while being conveyed to the heated gas stream, and ultrafine fibers can be spun.

When the molten electric field spinning method is adopted as the melt spinning method, first, the filament F is supplied from the supply port 110 and the filament F is heated in the heating unit 120 to obtain a molten liquid, as in the melt blow method. .. The molten liquid moves so as to be pushed out toward the nozzle 130 according to the speed at which the filament F is supplied from the supply port 110.

Next, under a state in which an electric field is formed between the nozzle 130 and the electrode 160, the molten liquid of the filament F is discharged from the nozzle 130 into the electric field for spinning. At this time, the molten liquid of the filament F is in a state of being charged with a positive polarity or a negative polarity depending on the polarity of the electric field. Taking the spinning unit 200 shown in FIGS. 6 and 7 (b) as an example, this electric field is generated by grounding the nozzle 130 and applying a voltage generated from the high voltage generator 162 to the electrode 160. It can be generated between the nozzle 130 and the electrode 160.
A voltage is applied to the electrode 160 so that the absolute value of the potential difference between the nozzle 130 and the electrode 160 is preferably 5 kV or more, preferably 10 kV or more, from the viewpoint of facilitating the formation of finer diameter fibers.
The absolute value of the potential difference between the nozzle 130 and the electrode 160 is preferably 100 kV or less, more preferably 80 kV or less, from the viewpoint of suppressing unintended discharge and leakage current and preventing malfunction of the manufacturing apparatus 10. As such, a voltage is applied to the electrode 160.
Due to the electrical repulsive force generated inside the discharged molten liquid, the molten liquid is three-dimensionally stretched and refined, and at the same time, the resin is cooled and solidified to form fine-diameter fibers. NS.

In particular, from the viewpoint of further increasing the miniaturization of the molten liquid to form finer diameter fibers, the melt spinning apparatus 100 includes a gas flow injection unit 140 and an electrode 160 as shown in FIG. 7 (b). It is more preferable to have both. That is, the electric field is supplied by supplying the heated gas flow from the gas flow generation unit 150 to the gas flow injection unit 140, injecting the gas flow from the gas flow injection unit 140, and applying the electrode to the electrode 160. It is more preferable that the molten liquid of the filament F is discharged from the nozzle 130 in a state of being charged in an electric field to be spun.

Further, regardless of whether the melt blow method or the molten electric field spinning method is adopted in the production of the fiber, the temperature of the gas flow injected from the gas flow injection unit 140 depends on the constituent components of the resin composition. From the viewpoint of facilitating the formation of fibers having a smaller diameter, the temperature is preferably 100 ° C. or higher, more preferably 200 ° C. or higher.
The temperature of the gas flow injected from the gas flow injection unit 140 can be appropriately changed according to the melting point of the resin used, but in reality, it is 500 ° C. or lower, preferably 450 ° C. or lower. That is, the gas flow injected from the gas flow injection unit 140 is preferably a heated gas.
For the same purpose, the flow rate of the gas flow injected at the discharge port of the gas flow injection unit 140 is preferably 5 L / min or more, more preferably 10 L / min, from the viewpoint of facilitating the formation of finer diameter fibers. It is min or more.
The flow rate of the gas flow injected at the discharge port of the gas flow injection unit 140 is preferably 500 L / min or less, more preferably 400 L / min or less, from the viewpoint of suppressing unintended breakage of the spun fiber.

By contacting a gas stream having at least one of such a temperature and an air volume, the stretching efficiency of the molten liquid can be increased due to the external force of the contacted gas stream. Further, since the space temperature around the nozzle can be maintained in a high state, the cooling and solidification of the molten resin can be delayed, and the stretched state of the molten liquid can be maintained for a long time. As a result, ultrafine fibers having a reduced diameter can be efficiently produced.
In particular, in the production of fibers by the molten electrospinning method, by bringing a gas flow into contact with the discharged molten liquid and spinning the fibers, in addition to improving the drawing efficiency of the molten liquid by contact with the heated gas, the charged melting is performed. Since the drawing efficiency can be further increased by the electric repulsive force generated in the liquid, there is an advantage that ultrafine fibers having a smaller diameter can be efficiently produced with high productivity.

The fiber produced by the above melt spinning method is an ultrafine fiber called a nanofiber having a fiber diameter of 10 μm or less when the fiber diameter is represented by a circle-equivalent diameter.
The fiber diameter of the nanofiber is preferably 0.1 μm or more from the viewpoint of improving the strength of the nanofiber.
The fiber diameter of the nanofiber is more preferably 5 μm or less, still more preferably 3 μm or less, from the viewpoint of improving the surface area and the adhesiveness by reducing the fiber diameter.
In particular, by using a resin composition for melt spinning, which is a filament, as a raw material in forming fibers, it is possible to obtain high handleability and high continuous supply while preventing thermal deterioration.

<Measurement method of median fiber diameter>
The fiber diameter of the fiber is determined by arbitrarily selecting 200 fibers excluding defects such as spun fiber lumps, intersections between fibers, and polymer droplets from a two-dimensional image observed by a scanning electron microscope, and in the longitudinal direction of the fibers. It can be measured by directly reading the length when a line orthogonal to is drawn as the fiber diameter. The median fiber diameter is obtained from the measured fiber diameter distribution, and this is used as the fiber diameter of the present invention.

The nanofibers or their deposits produced by the electrospinning method using the melt spinning apparatus 100 can be used for various purposes as a fiber molded body in which they are integrated.
Examples of the shape of the fiber molded body include a sheet, a cotton-like body, a thread-like body, and a porous film.
The fiber molded body may be used by laminating it with another sheet or by containing various liquids, fine particles, fibers and the like.
The fiber sheet adheres to human skin, teeth, gums, hair, skin of non-human mammals, teeth, gums, plant surfaces such as branches and leaves for non-medical purposes such as medical purposes, cosmetic purposes, and decorative purposes. It is preferably used as a sheet to be used.
It is also suitably used as a high-performance filter having high dust collection and low pressure loss, a battery separator that can be used at a high current density, a cell culture substrate having a high pore structure, and the like. The cotton-like body of the fiber is preferably used as a soundproofing material, a heat insulating material, or the like.

Although the present invention has been described above based on its preferred embodiment, the present invention is not limited to the above embodiment.
For example, the electrode 160 in the above-described embodiment has been described as an embodiment in which the electrode 160 is connected to the electrode 160 and includes a high voltage generator 162 for applying a voltage to the electrode 160, but as long as an electric field for charging the raw material F can be formed. In the above, there is no particular limitation on the mode.
Specifically, the nozzle 130, the electrode 160, and the high voltage generator 162 connected to the nozzle 130 and applying a voltage to the nozzle 130 may be provided, and the nozzle 130 and the collecting electrode may be provided. A voltage may be applied to at least one of the nozzle 130 and the collection electrode to generate an electric field. Even in this case, an electric field for charging the raw material F can be formed.

Regarding the above-described embodiment of the present invention, the following resin composition for melt spinning and a method for producing the same, and a fiber and a method for producing the same are disclosed.

<1>
A resin composition for melt spinning, which is a filament having a melt viscosity of 250 Pa · s or less and a tensile strength of 10 MPa or more at 200 ° C. and a shear rate of 0.1 s- ^1.

<2>
The resin composition has a melt viscosity of 0.05 Pa · s or more and 250 Pa · s or less, preferably 150 Pa · s or less, more preferably 50 Pa · s or less, still more preferably 50 Pa · s or less at 200 ° C. and a shear rate of 0.1 s- ^1. The resin composition for melt spinning according to <1> above, which is 10 Pa · s or less, preferably 0.1 Pa · s or more, and more preferably 0.5 Pa · s or more.
<3>
The resin composition has a tensile strength of 10 MPa or more and 150 MPa or less, preferably 12 MPa or more, more preferably 15 MPa or more, still more preferably 20 MPa or more, preferably 120 MPa or less, and more preferably 100 MPa or less. Alternatively, the resin composition for melt spinning according to <2>.
<4>
The resin composition for melt spinning according to any one of <1> to <3>, wherein the average cross-sectional diameter of the filament in a direction orthogonal to the length direction is 1 mm or more and 30 mm or less.

<5>
The average cross-sectional diameter in the direction orthogonal to the length direction of the filament is 1 mm or more and 30 mm or less, preferably 1.3 mm or more, more preferably 1.5 mm or more, preferably 20 mm or less, more preferably 15 mm or less, and further. The resin composition for melt spinning according to any one of <1> to <4>, preferably 5 mm or less, more preferably 1.7 mm or less.
<6>
The resin composition for melt spinning according to any one of <1> to <5>, wherein the ratio of the length to the average cross-sectional diameter of the filament (the length of the filament / the average diameter of the cross section of the filament) is 20 or more. ..
<7>
The ratio of the length to the average cross-sectional diameter of the filament (the length of the filament / the average diameter of the cross section of the filament) is 20 or more and 1000000 or less, preferably 50 or more, and more preferably 100 or more. > The resin composition for melt spinning according to any one of.
<8>
The resin composition for melt spinning according to any one of <1> to <7>, wherein the filament length is 50 mm or more and 10000 m or less, preferably 5000 m or less, and preferably 100 mm or more.

<9>
The resin composition contains a thermoplastic resin and contains
The content of the thermoplastic resin is 70 parts by mass or more and 100 parts by mass or less, preferably 75 parts by mass or more, more preferably 80 parts by mass or more, and further preferably 95 parts by mass or more with respect to 100 parts by mass of the resin composition. The resin composition for melt spinning according to any one of <1> to <8>.
<10>
The resin composition for melt spinning according to any one of <1> to <9>, which contains a thermoplastic resin as a main component.
<11>
The resin composition according to any one of <1> to <10>, wherein the resin composition contains one or more selected from polyolefin resins and polyester resins, and preferably contains one or more selected from polypropylene and polylactic acid-based resins. Resin composition for melt spinning.
<12>
The resin composition for melt spinning according to any one of <9> to <11>, wherein the thermoplastic resin contains a polylactic acid-based resin.

<13>
The above <9> to <12, wherein the thermoplastic resin contains one or more selected from polypropylene resins having a weight average molecular weight of 150,000 g / mol or less and polylactic acid resins having a weight average molecular weight of 150,000 g / mol or less. > The resin composition for melt spinning according to any one of.
<14>
Polypropylene resin is contained as the thermoplastic resin, and the thermoplastic resin is contained.
The weight average molecular weight of the polypropylene resin is 1000 g / mol or more and 150,000 g / mol or less, preferably 100,000 g / mol or less, more preferably 80,000 g / mol or less, preferably 5000 g / mol or more, and more preferably 10000 g / mol or more. The resin composition for melt spinning according to any one of <9> to <13>.
<15>
The thermoplastic resin contains a polylactic acid-based resin and contains
The weight average molecular weight of the polylactic acid-based resin is 1000 g / mol or more and 150,000 g / mol or less, preferably 100,000 g / mol or less, more preferably 80,000 g / mol or less, still more preferably 50,000 g / mol or less, and preferably 5000 g / mol or less. The resin composition for melt spinning according to any one of <9> to <14>, which is more preferably 10,000 g / mol or more.

<16>
The breaking strain is 1% or more and 20% or less, preferably 1.5% or more, more preferably 2% or more, further preferably 2.5% or more, and preferably 18% or less. The resin composition for melt spinning according to any one of <15>.
<17>
< The resin composition for melt spinning according to any one of 1> to <16>.
<18>
The resin composition for melt spinning according to <17>, wherein the additive comprises one or more selected from an elastomer, a plasticizer, a modifier, a decomposition inhibitor and a charge modifier.

<19>
Melting, which is a filament, has a step of forming a melt of a resin composition having a melt viscosity of 250 Pa · s or less at 200 ° C. and a shear rate of 0.1 s- ^{1 into a filament and cooling the molded product while transporting the molded product.} A method for producing a resin composition for spinning.
<20>
A filament manufacturing apparatus including an extrusion molding unit for extruding the molten liquid from a discharge port and a transport unit for transporting the molded product is used.
The production according to <19>, wherein the distance between the discharge port and the transport portion is 1 mm or more and 50 mm or less, preferably 30 mm or less, more preferably 15 mm or less, preferably 3 mm or more, and more preferably 5 mm or more. Method.
<21>
It is provided with an extrusion molding unit that extrudes the molten liquid from a discharge port for molding, a transport unit that conveys the molded product, and a cooling unit that cools the molded product.
The production method according to <19> or <20>, wherein the filament-shaped molded product is cooled by using at least one of an air cooling, a cooling roll, a gas tank, and a liquid tank.

<22>
The cooling unit is a liquid tank containing a liquid.
Using a filament manufacturing apparatus in which the transport unit is a transport roll arranged in a state of being partially immersed in the liquid.
The molded product discharged from the discharge port is directly received on the peripheral surface of the transport roll that has not been immersed in the liquid, and the molded product adhered to the peripheral surface is turned into the liquid by the rotation of the transport roll. The manufacturing method according to <21>, wherein the method is brought into contact with each other for cooling.
<23>
A step of extruding the molten liquid to form a filament and cooling the molded product while transporting the molded product is provided.
The ratio (V2 / V1) of the transfer speed V2 of the molded product to the extrusion speed V1 of the melt is 1 or more and 50 or less, preferably 3 or more, more preferably 5 or more, preferably 35 or less, more preferably. The production method according to any one of <19> to <22>, wherein the content is 25 or less.

<24>
The transport speed V2 of the molded product is 0.2 m / min or more and 200 m / min or less, preferably 1 m / min or more, more preferably 1.5 m / min or more, preferably 100 m / min or less, more preferably 50 m. The production method according to <23> above, wherein it is / min or less, particularly preferably 35 m / min or less.
<25>
Using the resin composition containing polypropylene,
The above <19> to <24>, wherein the resin composition is heated to 180 ° C. or higher and 280 ° C. or lower, preferably 190 ° C. or higher, preferably 260 ° C. or lower to obtain the melt. Manufacturing method.

<26>
A method for producing fibers using a melt spinning device.
The melt spinning apparatus directly communicates with and melts a supply port to which the raw material is supplied, a heating unit that melts the raw material supplied from the supply port without applying kneading force, and the heating unit. A nozzle for discharging the raw material is provided.
As the raw material, a resin composition for melt spinning, which is a filament having a melt viscosity of 250 Pa · s or less and a tensile strength of 10 MPa or more at 200 ° C. and a shear rate of 0.1 s- ^{1, is used, and the filament is used from the supply port.} A method for producing a fiber, in which the molten raw material is discharged from the nozzle and spun while supplying the resin.
<27>
The melt spinning device further includes a gas flow injection unit for transporting the raw material discharged from the nozzle to the gas flow.
The fiber according to <26>, wherein the molten raw material is discharged from the nozzle and spun while the filament is supplied from the supply port and the gas flow is injected from the gas flow injection unit. Manufacturing method.

<28>
The melt spinning apparatus further includes a charging means for charging the raw material discharged from the nozzle.
The <26> or <27>, in which the molten raw material is discharged from the nozzle into the electric field and spun while the filament is supplied from the supply port and the electric field is formed by the charging means. The method for producing a fiber according to.
<29>
A fiber formed by the resin composition for melt spinning according to any one of <1> to <18>.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the scope of the present invention is not limited to such examples. In the table below, the "-" column indicates that the raw material is not contained or the evaluation has not been performed.

[Examples 1-1 to 1-6 and Comparative Examples 1-1 to 1-3]
In this example and comparative example, the relationship between the composition of the resin composition and the flexibility and strength of the filament when producing the resin composition which is a filament is investigated. It also relates to the formability of fibers produced from these filaments.

[1. Filament manufacturing]
Using the filament manufacturing apparatus 10, a resin composition containing PP or PLA, a charge modifier, an elastomer, and a modifier in the proportions shown in Table 1 below is melt-kneaded, and a melt of the resin is discharged. It was extruded from the outlet 24 to obtain a molded product S. The diameter of the discharge port 24 was 5 mm, the distance D1 was 10 mm, the extrusion speed V1 of the molten liquid from the discharge port 24 was 3 to 4.2 m / min, and the transfer speed V2 of the molded product S was 1 to 2 m / min. In Example 1-1, using the filament manufacturing apparatus 10 having the structure shown in FIG. 3A, the molded product S was immersed in water in a liquid tank and water-cooled while transporting the molded product S. A resin composition which is a filament was produced.
Examples other than Example 1-1 and Comparative Examples 1-1 to 1-3 use a manufacturing apparatus 10 having a structure as shown in FIG. 2 and not provided with a cooling gas supply unit 45. A resin composition which is a filament was produced by using the transport unit 30 as a belt conveyor and naturally air-cooling the molded product S while transporting it. In Comparative Examples 1-3, PP filaments for 3D printers (manufactured by Uniplus Shiga Co., Ltd., MFR: 20 g / 10 min (conditions: 230 ° C., 2.16 kg)) were used.

The raw materials used for producing the filament are as follows.
Polypropylene: Polypropylene (manufactured by PolyMirae, MF650Y, melting point 160 ° C., MFR: 1800 g / 10 min (conditions: 230 ° C., 2.16 kg), weight average molecular weight: 79,000 g / mol.
-Polylactic acid A: A product of NatureWorks, product number 4032D, which was hydrolyzed in an environment of 85 ° C. and 95% RH for 18 hours to adjust the weight average molecular weight to 42,000 g / mol.
-Polylactic acid B: A product of NatureWorks, product number 4032D, which was hydrolyzed in an environment of 85 ° C. and 95% RH for 12 hours to adjust the weight average molecular weight to 81,000 g / mol.
-Polylactic acid C: manufactured by NatureWorks, product number 6252D (weight average molecular weight: 100,000 g / mol), MFR: 70 to 85 g / 10 min (conditions: 210 ° C., 2.16 kg).
-Polylactic acid D: manufactured by NatureWorks, product number 4032D (weight average molecular weight: 200,000 g / mol), MFR: 7 g / 10 min (conditions: 210 ° C., 2.16 kg).
-Charge adjuster: Sodium N-stearoylmethyl taurine (manufactured by Nikko Chemicals Co., Ltd., trade name: Nikkor SMT)
-Elastomer: Polyolefin-based elastomer (manufactured by Mitsui Chemicals, Inc., Toughmer PN-20300)
-Modifier: Low crystalline polyolefin (manufactured by Idemitsu Kosan Co., Ltd., L-MODU S400)

[2. Fiber manufacturing]
The resin composition, which is the filament obtained in each Example and Comparative Example, was supplied to the melt spinning apparatus 100 shown in FIG. 5 to produce fibers. Each Example and Comparative Example were manufactured by the molten electric field spinning method using the spinning unit 200 shown in FIG. The manufacturing conditions are shown below.

[Fiber manufacturing conditions]
-Manufacturing environment: 27 ° C, 50% RH
-Heating temperature in the heating unit 120: 250 ° C
-Discharge rate of molten liquid from nozzle 130: 2 to 6 g / min
-Voltage applied to nozzle 130 (stainless steel): 0 kV (grounded to ground)
-Voltage applied to electrode 160 (stainless steel): -20 kV
-Inner diameter at the tip of the nozzle 130: 0.4 mm
-Distance between the tip of the nozzle 130 and the collecting means: 600 mm
-Temperature of the air flow injected from the gas flow injection unit 140: 450 ° C.
-Flow rate of air flow injected from gas flow injection unit 140: 150 L / min

[Whether or not filament can be produced]
For each Example and Comparative Example, whether or not filaments could be produced was evaluated according to the following evaluation criteria. The results are shown in Table 1.
G: A filament having a filament cross-sectional diameter of 1 mm or more measured by the above-mentioned filament cross-sectional diameter measuring method can be produced.
P: The cross-sectional diameter of the filament measured by the above-mentioned method for measuring the average cross-sectional diameter of the filament is less than 1 mm, and the filament cannot be stably produced, or the produced filament is easily bent and has an unstable shape. It is difficult to recover and use as a filament.

[Filament melt viscosity and tensile strength]
Each measurement was performed by the method described above. The results are shown in Table 1.

[Average cross-sectional diameter of filament and standard deviation of cross-sectional diameter of filament]
The average cross-sectional diameter of the filament was measured by the above-mentioned method for measuring the average cross-sectional diameter of the filament, and the standard deviation of the standard deviation of the cross-sectional diameter of the filament was obtained together with this. The smaller the standard deviation, the more uniform the cross-sectional diameter of a single filament. The results are shown in Table 1.

[Measurement of roundness of filament cross section]
As an evaluation of stability in filament production, the roundness of the filament cross section was measured. The roundness of the cross section of the filament was measured by measuring the major axis and the minor axis at each measurement point in the same manner as in the measurement of the cross-sectional average diameter described above, and calculating the minor axis / major axis ratio at each measurement point. The arithmetic mean value of the minor axis / major axis ratio at all measurement points was defined as roundness.
The roundness in this measurement method is expressed in the range of more than 0 (zero) and 1 or less, and is calculated as 1 if the cross-sectional shape of the filament is a perfect circle. The closer the roundness is to 1, the more the cross-sectional shape is a perfect circle. It is close to. Since the shape of the discharge port 24 in the filament manufacturing apparatus 10 used in this embodiment is a circular shape having a roundness close to 1, the fact that the roundness of the filament cross section is close to 1 means that the resin melt liquid is used. This means that there is little change in shape between the cross-sectional shape immediately after extrusion molding from the discharge port 24 and the cross-sectional shape of the filament after cooling and solidification, and the filament can be stably produced. The results are shown in Table 1.

[Ratio of filament length to average cross-sectional diameter of filament]
The ratio was calculated by measuring each of the above methods and dividing the filament length by the average cross-sectional diameter of the filament. The results are shown in Table 1.

[Filament bending evaluation]
The filaments produced in each Example and Comparative Example were subjected to bending evaluation by the following method. When one end of a linear filament with a length of 15 cm is manually fixed, and in that state, the other end of the filament is bent so as to be in contact with the fixed one end side with the central portion of the filament as the bending axis. , Based on the angle of the filament when the filament breaks, it was evaluated according to the following criteria. The results are shown in Table 1. The flexibility is higher in the order of C <B <A, which facilitates handling during storage and spinning.
<Evaluation criteria>
A: Even if the other end of the filament is moved 180 degrees and bent, the filament is not broken and both ends of the filament can be easily brought into contact with each other, which is excellent in flexibility.
B: When the other end of the filament is moved by 120 degrees or more and less than 180, the filament breaks and the flexibility is slightly inferior.
C: When the other end of the filament is moved by less than 120 degrees, the filament breaks and the flexibility is poor.

[Fracture strain of filament]
The filaments produced in each Example and Comparative Example were calculated based on the above-mentioned method for measuring and calculating breaking strain using a tensile tester (manufactured by Shimadzu Corporation, AG-X plus). The results are shown in Table 1.

[Measurement of median fiber diameter]
Under the production conditions of Examples and Comparative Examples, the fiber diameter of the spun fiber was measured by the method described above. In addition, in the case where the fiber could not be produced because the molten liquid could not be discharged from the spinning unit 200, it was classified as "spinning impossible". The results are shown in Table 1.

As shown in Table 1, the conditions of each example are the filament bending evaluation and the filament bending evaluation while having the filament length capable of continuous supply even when the raw materials of the resin used are different from those of the comparative example. Since it has a high level of tensile strength, it can be wound around a shaft or bent to save space, and it has high handleability and high continuous supply that can be pushed into a melt spinning device using a gear. It is a thing. Further, it can be seen that the fibers produced using the filaments obtained in each example are all extremely fine and the fiber production efficiency is high.
In particular, according to Examples 1-4 to 1-6, even when PLA, which was difficult to apply to the melt spinning method by the conventional technique, is used, the raw material is deteriorated due to heat, hydrolysis, etc. It can also be seen that fibers are less likely to occur and fibers can be produced with high production efficiency.
As shown in Table 1, the PLA used in Comparative Example 1-2 had a higher melt viscosity than the resin composition of each example, so that it was difficult to discharge the PLA in the manufacturing apparatus 10, and the filament was formed. Could not be manufactured.

The tensile strength and breaking strain of the filaments produced under the conditions of Examples 1-5 and 1-6 are the values at the time of overload because the load cell used in the tensile test was 100N. It is shown that the tensile strength and breaking strain are high. The tensile strength of Examples 1-5 and 1-6 was 100 MPa or less.
On the other hand, the filaments for 3D printers shown in Comparative Examples 1-3 showed the maximum test force in the tensile test, but the breaking strain could not be measured because they continued to stretch without breaking.

[Examples 2-1 to 2-11]
In this example, when the resin composition which is a filament is produced, the influence of the distance D1 between the discharge port 24 and the transport portion 30 on the filament production is investigated.
Using a manufacturing apparatus 10 having a structure as shown in FIG. 2 and not provided with a cooling gas supply unit 45, 100% by mass polypropylene as a thermoplastic resin (the same as that used in Example 1-1). ) As a raw material, and after melt-kneading, the melted resin liquid was extruded from the discharge port 24 to obtain a molded product S. The diameter of the discharge port was 5 mm, and the distance D1, the extrusion speed V1 of the molten liquid from the discharge port 24, the transfer speed V2 of the molded product S, and the V2 / V1 ratio were as shown in Table 2 below. In addition, the transport unit 30 is in the form of a belt conveyor, and the molded product S is naturally air-cooled while being transported to produce a resin composition which is a filament of each example.
Table 2 also shows the details of the production conditions of Example 1-1.

[Average cross-sectional diameter of filament and its standard deviation, roundness of cross section]
The procedure was performed as described above [Average diameter of filament cross section and standard deviation thereof] and [Measurement of roundness of filament cross section]. The results are shown in Table 2.

[Ratio of filament length to average filament cross-sectional diameter]
The average cross-sectional diameter and length of the filaments were measured by the methods described above, and the ratio was calculated by dividing the filament length by the average cross-sectional diameter of the filaments. The results are shown in Table 2.

[Whether or not filament can be produced]
Evaluation was made according to the above-mentioned evaluation criteria. The results are shown in Table 2.

As shown in Table 2, it can be seen that by setting the distance D1 between the discharge port 24 and the transport portion 30 in the range of 5 mm or more and 50 mm or less, filaments having a predetermined diameter can be stably and continuously manufactured.
Further, by setting at least one of the extrusion speed V1 of the molten liquid from the discharge port 24, the transport speed V2 of the molded product S and the V2 / V1 ratio in a suitable range, the variation in the cross-sectional diameter of the filament is small and the cross section is cross-sectional. A filament having a good shape can be continuously and stably produced.

10 Filament manufacturing equipment 20 Extrusion molding unit 30 Transport unit 40 Cooling unit 100 Melting spinning equipment 110 Supply port 120 Heating unit 130 Nozzle

Claims (15)

200 ° C. and a melt viscosity at a shear rate of 0.1s ^-1 is not higher than 250 Pa · s, Ri filament der tensile strength is not less than 10 MPa,
A resin composition for melt spinning , wherein the average cross-sectional diameter of the filament in a direction orthogonal to the length direction is 1 mm or more and 30 mm or less. 200 ° C. and shear rate 0.1s ^-1 Is a filament having a melt viscosity of 250 Pa · s or less and a tensile strength of 10 MPa or more.
The filament contains a polylactic acid resin and contains
A resin composition for melt spinning, wherein the polylactic acid-based resin has a weight average molecular weight of 1000 g / mol or more and 100,000 g / mol or less. The resin composition for melt spinning according to claim 1 or 2, wherein the ratio of the length to the average cross-sectional diameter of the filament (the length of the filament / the average diameter of the cross section of the filament) is 20 or more. The resin composition for melt spinning according to any one of claims 1 to 3, wherein the resin composition contains one or more of a polyolefin resin and a polyester resin. The resin composition for melt spinning according to any one of claims 1 to 4 , wherein the resin composition contains a polylactic acid-based resin. The resin composition for melt spinning according to any one of claims 1 to 5 , wherein the breaking strain is 1 % or more and 20% or less. Melt viscosity at 200 ° C. and a shear rate of 0.1s ^-1 is molded molten liquid of resin composition is not more than 250 Pa · s to filamentary, have a step of cooling while conveying the molded product,
A method for producing a resin composition for melt spinning , which is a filament, for obtaining a filament having an average cross-sectional diameter of 1 mm or more and 30 mm or less in a direction orthogonal to the length direction. A filament manufacturing apparatus including an extrusion molding unit for extruding the molten liquid from a discharge port and a transport unit for transporting the molded product is used.
The manufacturing method according to claim 7, wherein the distance between the discharge port and the transport portion is 1 mm or more and 50 mm or less. A step of extruding the molten liquid to form a filament and cooling the molded product while transporting the molded product is provided.
The production method according to claim 7 or 8, wherein the ratio (V2 / V1) of the transfer speed V2 of the molded product to the extrusion speed V1 of the molten liquid is 1 or more and 50 or less. A method for producing fibers using a melt spinning device.
The melt spinning apparatus directly communicates with and melts a supply port to which the raw material is supplied, a heating unit that melts the raw material supplied from the supply port without applying kneading force, and the heating unit. A nozzle for discharging the raw material is provided.
As the raw material, a resin composition for melt spinning, which is a filament having a melt viscosity of 250 Pa · s or less and a tensile strength of 10 MPa or more at 200 ° C. and a shear rate of 0.1 s- ^{1, is used, and the filament is used from the supply port.} A method for producing a fiber, in which the molten raw material is discharged from the nozzle and spun while supplying the resin. The melt spinning apparatus uses the raw material discharged from the nozzle as a raw material.
Further equipped with a gas flow injection unit for transporting to a gas flow,
While supplying the filament from the supply port and in a state where the gas flow is injected from the gas flow injection unit, the melted raw material is discharged from the nozzle and spun.
And / or
Further equipped with a charging means for charging,
The fiber according to claim 10, wherein the molten raw material is discharged from the nozzle into the electric field and spun while the filament is supplied from the supply port and the electric field is formed by the charging means. Production method. 200 ° C. and shear rate 0.1s ^-1 The resin composition having a melt viscosity of 250 Pa · s or less is provided with an extrusion molding unit for extruding the resin composition into filaments and a transport unit for receiving the extrusion-molded molded product and transporting it to the next step.
An apparatus for producing a resin composition for melt spinning, which is a filament, in which the distance between the discharge port of the resin composition and the transport portion is 50 mm or less, and the diameter of the discharge port is 1 mm or more and 50 mm or less. A supply port to which the raw material is supplied, a heating unit that melts the raw material supplied from the supply port without applying kneading force, and a nozzle that directly communicates with the heating unit and discharges the melted raw material. With and
As the raw material, 200 ° C. and a shear rate of 0.1 s ^-1 A resin composition for melt spinning, which is a filament having a melt viscosity of 250 Pa · s or less, is used, and the molten raw material is discharged from the nozzle to be spun while the filament is supplied from the supply port. Is a melt spinning device. 200 ° C. and shear rate 0.1s ^-1 The resin composition is provided with an extrusion molding unit for extruding a resin composition having a melt viscosity of 250 Pa · s or less into a filament, and a transport unit for receiving the extrusion-molded molded product and transporting it to the next step. An apparatus for producing a resin composition for melt spinning, which is a filament, in which the distance between the discharge port and the transport portion is 50 mm or less and the diameter of the discharge port is 1 mm or more and 50 mm or less.
A supply port to which the resin composition for melt spinning produced by the manufacturing apparatus is supplied, a heating unit for melting the resin composition supplied from the supply port without applying kneading force, and the heating unit. A melt spinning device including a nozzle that directly communicates with the melted resin composition and discharges the melted resin composition. The resin composition discharged from the nozzle is
The melt spinning apparatus according to claim 13 or 14, further comprising a gas flow injection unit for transporting to a gas flow and / or an electrode for charging.

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