JP2009299212A - Spinning method, and method and apparatus for producing fiber using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spinning method by which a fiber can be produced in good efficiency by efficiently irradiating a thermoplastic resin with a laser beam to melt the resin. <P>SOLUTION: The spinning method is carried out as follows. The laser beam in a line shape is formed by an optical system 2 based on the laser beam emit from a laser beam generator 1. The formed line-shaped laser beam is radiated along a prescribed irradiation line, and a material 9 formed of the thermoplastic resin material is continuously heated and melted on the irradiation line while moving the material 9 by a feed roller 10 so as to cross the irradiation line. The melted portion of the heated and melted material 9 is electrified by applying a high voltage to the material 9 by an electrode part 5 to electrify the material 9, and many needle-shaped protrusion parts are formed in the melted portion by the electrostatic force caused by the electrification to spin the fiber from the needle-shaped protruded parts to a collector 8. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a spinning method in which a raw material is heated and melted by irradiating a laser beam, a melted portion is charged and fibers are spun by electrostatic force, and a fiber manufacturing method and apparatus using the spinning method.

  In recent years, nanofibers have attracted attention. A fiber (nanofiber) having a fiber diameter of submicron or nanometer order is attracting attention because it can develop a new material utilizing a high specific surface area and fiber form. In general, as a method for producing ultrafine fibers, there is a melt blow method in which a polymer melt is extruded at high pressure and blown off with hot air to produce ultrafine (fine) fibers. In this method, ultrafine fibers are produced by the pressure applied to the melt in the nozzle and the shearing force generated by hot air. However, although such a method can produce ultrafine fibers having a diameter of several micrometers or more, it is difficult to produce nanofibers.

  Therefore, as a method for producing nanofibers, an electrostatic spinning method is used in which fibers are formed by applying a high voltage to a polymer solution or polymer melt. Hereinafter, the former method using a polymer solution is referred to as a solvent-type electrospinning method, and the latter method using a polymer melt is referred to as a melt-type electrospinning method. Since the melt type electrospinning method is a method derived from the solvent type electrospinning method, these spinning principles are basically the same.

  In the solvent-type electrostatic spinning method, first, a polymer solution is put into a syringe, and a high voltage is applied between a nozzle attached to the tip of the syringe and a collector (collecting unit) to generate a high potential difference. As a result, the polymer solution into which the charge has been introduced flies by receiving an electrostatic attraction from the tip of the nozzle in the direction of the collector having the opposite charge, causing whipping motion, while the solvent evaporates during this process. By doing so, nanofibers are formed. The whipping vibration (or whipping vibration) referred to here is a fiber that is traversed with hundreds to tens of thousands of rotations per second while the fiber pulled by electrostatic attraction pulls to the collector. It means the behavior that is formed. Such a solvent-type electrospinning apparatus is widely used because it can be easily produced, and nanofibers have been developed from many polymer materials that are soluble in a solvent. Therefore, at present, it is no exaggeration to say that the electrospinning method refers to the solvent-type electrospinning method.

  On the other hand, the melt-type electrospinning method is a method similar to the above-described melt-blowing method, in which a charge is imparted to the molten polymer, and the charged melt and an electrode (collector) having a different charge are used. In this method, the melt is spontaneously stretched by an electric attractive force to produce fine fibers. In the melt type electrospinning method, since the electric charge is very small, the diameter of the obtained fiber can be made smaller than the diameter of the fiber obtained by the melt-blowing method, but nanofibers are obtained by causing whipping vibration. It was not reached. However, in the melt-type electrospinning method, since no solvent is used, it is not necessary to recover the solvent, and it is not necessary to remove the residual solvent from the collected fibers. Therefore, it has been expected that the melt type electrospinning method is environmentally friendly and can produce ultrafine fibers with high productivity as compared with the solvent type electrospinning method.

As described above, the melt-type electrospinning method has not been studied very much at present, although its development is eagerly desired. The following reasons can be considered as the reason.
(1) Since electrospinning is a mechanism that occurs when the electrical attractive force in the collector direction exceeds the surface tension and viscoelastic force of the polymer, in the case of the melt-type electrospinning method, higher voltage and higher temperature And a lower viscosity is required for the melt.
(2) In the case of the solvent-type electrostatic spinning method, in addition to the draft drawing of the polymer solution during spinning, the solvent from the solution is volatilized, and the fiber diameter is reduced by this volatilization coupled with the draft drawing. In the case of the melt-type electrospinning method, since the solvent is not included, the fiber diameter depends only on draft drawing, and the production of nanofibers is a concern in principle.
(3) In the case of the melt type electrospinning method, a heating device capable of applying a high voltage to the melt is required. However, in the electric heating method generally employed as the heating device, a power source is used for high voltage action. The entire apparatus becomes complicated and unstable in order to induce discharge in the part and prevent such discharge.
(4) Since the resin in the solid state has low electrical conductivity, it is difficult for the high voltage applied to the resin in the solid state to be effectively transmitted to the melting part.

  In the melt type electrospinning method, Patent Document 1 describes (1) polymer for the purpose of improving the above-mentioned adverse effects in the electric heating method and the deterioration of physical properties of the resin due to long-term heat retention for lowering melt viscosity. A step of supplying, (2) an irradiation step of irradiating the supplied polymer with a laser to make the polymer deformable, and (3) electrically pulling the deformable polymer to reduce the diameter. There has been proposed a fiber assembly manufacturing method including a fiberizing step of stretching and fiberizing, and (4) a fiber assembly forming step of collecting the fibers to form a fiber assembly. In this document, it is described that a solvent is not required unlike the solution electrostatic spinning method because heat is applied to the fiber as a polymer by laser irradiation to make it deformable (electrospinable). . Furthermore, a method of supplying a rod-like polymer instead of supplying fibers is also described.

  Patent Document 2 discloses a method of reducing the viscosity of a thermoplastic polymer fiber or spun fiber as a raw fiber by reducing the viscosity by irradiating with infrared rays. On the other hand, Patent Document 3 discloses a melt-type electrospinning method in which a linear resin is irradiated with a laser beam having a beam diameter 2 to 50 times the average diameter of the linear resin to generate ultrafine fibers. ing.

All of the conventional electrospinning methods using a laser beam are techniques for irradiating a linear material with a beam of laser beam. This requires a technique to focus on a large number of linear thermoplastic polymers one by one and precisely control a large number of beams. On the other hand, if a beam diameter with a large diameter is used with reduced accuracy, However, the laser beam is irradiated on portions other than those necessary for the irradiation, and the laser beam irradiation efficiency is extremely low.
Japanese Patent Laying-Open No. 2005-154927 (Claim 1, paragraphs [0006], [0015], [0018] to [0020], [0025], FIGS. 1 to 3) JP 2007-262644 (Claims 1 and 6, paragraphs [0003], [0004], [0019], FIG. 13) JP 2007-239114 A (claim 4, paragraph [0014])

  Accordingly, an object of the present invention is to provide a spinning method capable of efficiently producing a fiber by efficiently irradiating a thermoplastic resin with laser light and melting it, and a fiber capable of producing a fiber assembly composed of ultrafine fibers. It is to provide a manufacturing method and apparatus.

  The spinning method according to the present invention irradiates a laser beam emitted from a light source along a predetermined irradiation line, and moves the material made of a thermoplastic resin material so as to cross the irradiation line. A plurality of needle-like protrusions are generated by electrostatic force by continuously melting by heating and charging the melted portion of the heat-melted material, and fibers are spun from the needle-like protrusions. . Further, the sheet-like material is irradiated with laser light over the entire width in the width direction to be melted by heating, and two or more acicular protrusions are generated per 2 cm width of the irradiation line. Further, the present invention is characterized in that a laser beam is irradiated over the entire length along the axial direction of the cylindrical material to heat and melt, and two or more acicular protrusions are generated per 2 cm of the width of the irradiation line. Furthermore, the spun fiber is heated by irradiation with radiant heat rays, and is elongated and thinned by whipping vibration. Furthermore, the spun fiber is whipped at a frequency of 100 times / second or more. Furthermore, the width of the laser beam irradiation range in the irradiation line is 0.5 mm or more.

  The fiber manufacturing method according to the present invention is characterized in that the fiber spun by the above spinning method is collected in a collector and laminated with each other to form a fiber assembly.

  The fiber manufacturing apparatus according to the present invention moves a laser irradiation unit that controls laser light emitted from a light source to be irradiated along a predetermined irradiation line, and a material made of a thermoplastic resin material so as to cross the irradiation line. And a moving part that heats and melts the material continuously in the irradiation line, and a plurality of needle-like protrusions are generated by electrostatic force by charging the melting part of the heat-melted material. A spinning part for spinning the fiber from the part and a collecting part for collecting the spun fiber are provided. Furthermore, the spinning unit includes an electrode unit disposed in proximity to the melting site, and a voltage application unit that applies a voltage between the electrode unit and the collection unit. Furthermore, a heating unit is provided between the electrode unit and the collecting unit to heat the fiber spun from the needle-like projecting portion with radiant heat rays. Furthermore, the collection unit forms a fiber assembly by collecting the spun fibers in a collector and overlaying them on each other.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have used a thermoplastic resin that uses a laser beam that irradiates in a line instead of a laser beam that irradiates in a spot shape used in conventional laser melt electrostatic spinning. We have discovered a technology for simultaneously forming a large number of fibers by irradiating a material made of a material with a laser beam in a line.

  In the present invention, by irradiating the line-shaped laser beam, the raw material made of the thermoplastic resin material can be melted locally and in a short time, so that it is not necessary to maintain a high-temperature melt for a long time. As a result, unlike the conventional melt-type electrospinning method, the present invention can suppress the diffusion of thermal energy and thermal decomposition of the thermoplastic resin material. Electrospinning is possible. Furthermore, electrostatic spinning of a thermoplastic resin having a high melting point, for example, a liquid crystal polymer is possible, and fibers composed of a high melting point resin (such as a liquid crystal polymer), in particular, ultrafine fibers can be obtained.

  When the material is cylindrical, a large number of needle-like protrusions are formed by electrostatic force from the heated and melted surface by irradiating laser light in a line along the axial direction of the cylinder rotating at a relatively low speed. Thus, the fiber can be spun from the needle-like protrusion.

  In addition, in the case of a sheet-like material such as a film or sheet-like material, or a sheet material in which fiber bundles are arranged in parallel, the surface is irradiated with laser light in a line shape along the width direction and heated and melted. By charging the melted portion of the raw material, a large number of needle-like protrusions can be generated by electrostatic force, and fibers can be spun from each needle-like protrusion.

  Features of the spinning method according to the present invention are as follows: (1) Laser light is irradiated without gaps over the entire width or length of the material, so that there is little irradiation loss and the melting efficiency of the thermoplastic resin material is high; Since fibers are spun at random from the protrusions, a large number of fibers can be produced at the same time, and (3) the fibers are spun by electrostatic force from the needle-like protrusions generated at the melting site, so that the fibers are made of thermoplastic resin. Energy can be produced efficiently.

  In the spinning method according to the present invention, the spun fiber is heated by radiant heat rays so that the spun fiber is subjected to whipping vibration at least 100 times per second in an atmosphere in the vicinity of the melting point of the thermoplastic resin material. It can be efficiently manufactured in large quantities. By setting the irradiation range of the heating part heated by radiant heat rays to a length of 30 mm or more, the spun fiber is heated and whipped to vibrate, and the fiber is elongated to obtain an ultrafine fiber. In particular, a fiber having an average fiber diameter of 5 μm or less may be whipped at a frequency of 100 times / second or more for spinning.

  The generation density of the needle-like protrusions is higher as the applied voltage to the melted portion of the material is higher, and becomes denser as the energy of the laser beam is larger, and becomes coarser as the applied voltage is lower and the energy of the laser beam is smaller. The generation density of the needle-like protrusions also depends on the viscosity of the polymer in the molten state, so the conditions cannot be determined uniformly. However, in order to produce fibers stably and efficiently, the density is at least 2 cm in width. Two or more are required.

  Further, by setting the width of the irradiation range of the laser beam in the irradiation line to 0.5 mm or more, it is possible to perform laser irradiation effective for heating and melting the material in a line shape.

  In the conventional spot-type laser beam melting type electrospinning method, fibers and linear objects are to be melted, and only one fiber can be formed from one of these objects. In the present invention, a melted portion is formed in a line shape by a laser beam, and a needle-like protruding portion is generated like a raindrop by an electrostatic force from a melted portion, and fibers are spun simultaneously from a number of locations, so extremely high productivity. Can produce fiber. With only the amount of heat of fusion using only laser light, thin fibers are more likely to be cooled, and the time and amount of heat for thinning due to whipping vibration are insufficient, so that further fiber diameter reduction is unlikely to occur. Therefore, in the present invention, since a heating unit that heats the spun fiber as a heat space that sufficiently performs whipping vibration is provided by radiant heat rays, it is possible to generate ultrafine fiber by whipping vibration, and the generated ultrafine fiber A uniform sheet-like ultrafine fiber nonwoven fabric can be obtained.

  If the produced ultrafine fibers are collected in a collector, a multilayered nonwoven fabric can be easily produced. If the ultrafine fibers are collected while moving the collector, it is possible to produce a nonwoven fabric with a uniform thickness.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings as necessary. FIG. 1 is a schematic configuration diagram illustrating an example of an embodiment of the present invention. The fiber manufacturing apparatus includes a laser beam generator 1 that emits a laser beam, an optical system 2 that generates a line-shaped laser beam 3 from the laser beam, a high-voltage applying device 4 that applies a voltage to the electrode unit 5, and a radiant heat ray. And a heating roller 6 for heating, a conveyor 8 for collecting the generated fibers 7 on the surface of the conveyor belt, and a supply roller 10 for conveying a plate-shaped material 9 made of a thermoplastic resin material. In FIG. 1, the vertical direction of the paper surface is the length direction of the material 9 and coincides with the supply direction indicated by the arrow. The left-right direction is the thickness direction of the material 9, and the direction orthogonal to the paper surface is the width direction of the material 9. The line-shaped laser beam generated by the optical system 2 is irradiated along an irradiation line set in the width direction of the material 9 (direction orthogonal to the paper surface).

  Then, the line-shaped laser light generated in the optical system 2 based on the laser beam emitted from the laser beam generator 1 is irradiated along the irradiation line set in the width direction of the material 9, and the thermoplastic resin. The raw material 9 made of the material is supplied in the length direction by the supply roller 10 and moves across the irradiation line, whereby the raw material 9 is continuously heated and melted in the irradiation line. The melted portion of the material 9 heated and melted (indicated by the hatched portion at the tip of the material 9 in FIG. 1) is formed by melting the lower end of the material 9 along the irradiation line.

  FIG. 2 is a schematic diagram relating to the melted portion formed at the lower end of the material 9. When a voltage is applied to the electrode unit 5 from the high voltage applying device 4, the material 9 is charged, and an electrostatic force is generated between the electrode unit 5 and the transport conveyor 8 that is grounded, and a large number of needle-like protrusions protrude from the melting portion of the material 9 Part 9a is generated. Then, the fibers 7 are spun from the needle-like protrusions 9a toward the conveyor 8 by electrostatic force.

  Since the needle-like protrusions 9a generated at the melting site are randomly generated like raindrops, the spun fibers are also randomly generated and collected on the transport belt of the transport conveyor 8. The collected fibers are layered to form a fiber assembly. The spun fiber 7 is heated by radiant heat rays when passing through the heating unit 6 and is thinned by whipping vibration.

  Examples of the light source used in the laser beam generator 1 include a YAG laser, a carbon dioxide (CO2) laser, an argon laser, an excimer laser, a helium-cadmium laser, and a solid semiconductor laser. Of these laser light sources, a carbon dioxide laser is preferable because of its high power efficiency and high meltability of the thermoplastic resin.

  In addition, since it is possible to transmit fiber, conversion efficiency is high, equipment cost and operation cost are low, a solid semiconductor laser may be used, but in many cases, the transmittance is high. A material that easily absorbs and generates heat, such as a laser beam, may be contained in a thermoplastic resin or coated resin to melt the resin. The wavelength of the laser beam is, for example, about 200 nm to 20 μm, preferably 500 nm to 18 μm, more preferably about 1 to 16 μm (particularly 5 to 15 μm).

  The optical system 2 is preferably one that generates a line-shaped laser beam in which the energy density in the irradiation line is as uniform as possible. Specifically, (1) an optical system that uses a beam expander and a cylindrical lens, (2) an optical system that scans a laser beam using a motor and a mirror, and (3) a multistage phase beam branching diffractive optical component (DOE) ), (4) an optical system using a kaleidoscope, and the like.

  As described above, there are various methods for generating a laser beam in a line shape. Here, a combination of a beam expander and a cylindrical lens will be described. The beam expander in this system has a role of expanding the laser beam into a parallel light beam having a constant magnification. The Galileo type beam expander has the following features: (1) The total length of the optical system can be made relatively short by combining concave and convex lenses, and (2) it can be configured with a minimum number of lenses because it is advantageous for correcting spherical aberration. ing.

  In the cylindrical lens, when the incident surface (two-dimensional) of the lens is divided into two components of the X-axis and the Y-axis, there is a curvature that acts as a lens only on one axis, and there is no curvature on the other axis. . Therefore, only the unidirectional component of the object acts as a lens and can be used to convert the laser beam into a line.

  The intensity distribution of laser light is generally non-uniform because it mainly consists of a Gaussian distribution, but a uniform intensity distribution (top hat) can be realized by using a beam homogenizer.

  Although the irradiation method of the line-shaped laser beam 3 is not particularly limited, a method of irradiating the material from a direction substantially perpendicular to the material surface is preferable because the material can be irradiated locally. What is necessary is just to set suitably the range which irradiates a laser beam 3 to a raw material according to the shape of a raw material. The generated line-shaped laser beam is a laser beam having substantially an energy distribution, and a region having an energy density effective for thermal melting is formed in a band shape along the irradiation line, and has a predetermined length in the longitudinal direction. In the short direction, it is formed to a predetermined depth with a predetermined width. The length L, width W, and depth d of the heating and melting region in the irradiation range of the line-shaped laser light are formed by heating and melting by irradiating the surface of the plate-shaped and thick transparent PMMA resin material from the vertical direction for 10 seconds. What is necessary is just to measure and set the length, width | variety, and depth of the recessed part.

  When the width of the plate-shaped (or sheet-shaped) material is smaller than the length L, it may be adjusted so as to match the width of the material by masking the laser beam as necessary. When the width of the material is larger than the length L, a plurality of line-shaped laser beams may be generated and irradiated in parallel with the irradiation line. For example, when the width of the material is 90 cm, if the length L of the line-shaped laser beam is 150 mm, six sets of line-shaped laser beams may be irradiated in parallel along the irradiation line.

  For example, in the case of a plate-shaped material, the width W of the line-shaped laser light is preferably at least twice the thickness, more preferably 0.5 mm or more and about 2 to 10 times the thickness of the material. In the case of a plate-shaped material, if the width W of the laser beam is smaller than 0.5 mm, there will be a time difference in heating and melting from the irradiation surface of the material to its back surface, making it impossible to perform uniform heating and melting in the thickness direction of the material. As a result, deformation such as curling occurs at the melting site.

  In order to melt the thermoplastic resin material, it may be controlled so that the energy density of the laser beam necessary for heating to a temperature not lower than the melting point of the thermoplastic resin and not higher than the ignition point of the thermoplastic resin is obtained. When manufacturing a fiber, the one where an energy density is large is preferable. The specific output of the laser beam may be appropriately selected according to the physical property value (melting point, LOI value (limit oxygen index)) of the thermoplastic resin material used as the material, the shape of the material, the moving speed of the material, etc. 0.1 to 50 W, preferably 1 to 100 W, more preferably about 15 to 70 W (particularly 30 to 50 W). The condition setting for laser light may be adjusted by measuring the temperature at the melted part of the material, but if high voltage is applied to the resin in a low viscosity state, the output of the laser beam is from the point of simplicity. It is preferable to control by.

  As a laser beam irradiation method, the material may be irradiated from one direction, but from the viewpoint that the material can be melted uniformly and sufficiently, the melted portion may be irradiated simultaneously from a plurality of directions. . For example, in the case of a plate-shaped material, it is sufficient to irradiate along the same irradiation line from two directions of the front surface and the back surface, and more than two directions, preferably 2-6 directions, more preferably 3-5 directions are the same. You may make it irradiate to an irradiation line.

  Such irradiation from a plurality of directions may be performed using a plurality of laser light sources. However, in order to efficiently melt the material, a laser beam emitted from a single laser light source is divided into a plurality of directions. You may make it irradiate from.

  Examples of the thermoplastic resin material used for the material include olefin resins (for example, polyethylene resins such as polyethylene, polypropylene resins such as polypropylene), styrene resins (for example, polystyrene, ABS resin, AS resin, etc.), Vinyl resins (eg, vinyl chloride resins such as polyvinyl chloride, (meth) acrylic resins such as polymethyl methacrylate, ethylene-vinyl alcohol copolymer resins, etc.), polyester resins (eg, polyethylene naphthalate type) , Aromatic polyester resins such as polybutylene terephthalate, polytrimethylene terephthalate and polyethylene terephthalate, aliphatic polyester resins such as polylactic acid, wholly aromatic polyester resins such as polyarylate, liquid crystal polyester Resin), polyamide resin (eg, aliphatic polyamide resin such as polyamide 6, semi-aromatic polyamide resin such as nylon 9MT, aromatic polyamide resin such as MXD6, liquid crystal polyamide resin, etc.), polyimide resin Resin (for example, thermoplastic polyimide, polyetherimide, etc.), polycarbonate-based resin (for example, bisphenol A type polycarbonate), thermoplastic polyurethane-based resin, polyphenylene sulfide-based resin (for example, polyphenylene sulfide), polyphenylene ether-based resin (for example) For example, polyphenylene ether), polyacetal resin (for example, polyoxymethylene), polyether ketone resin (polyether ketone, polyether ether ketone, etc.), polysulfone resin For example, polysulfone, polyether sulfone, etc.) and the like. These thermoplastic resins can be used alone or in combination of two or more.

  Among these thermoplastic resins, a resin having a functional group (polar group) in the main chain or side chain of the polymer, for example, from the point that the electrostatic force can be improved by sufficiently reaching the molten part at the tip, for example, (Meth) acrylic resins, ethylene-vinyl alcohol copolymer resins, polyester resins, polyamide resins and the like are preferable. Since the electrical resistance of such a resin decreases at high temperatures, it is easy to form ultrafine fibers. Furthermore, from the viewpoint of easily forming ultrafine fibers such as nanofibers, a low-viscosity thermoplastic resin such as a polyester-based resin, a polyamide-based resin, and a polyolefin-based resin is preferable. When these thermoplastic resins are used, ultrafine fibers having a uniform diameter can be produced while having a nanometer-sized fiber diameter. In particular, in the method of the present invention, even a biodegradable plastic for which it is difficult to select a solvent or an engineering plastic having a high melting point can be easily spun.

  Examples of biodegradable plastics include aliphatic polyester resins and aliphatic polyamide resins. Of these, aliphatic polyester resins are preferred. Examples of the aliphatic polyester-based resin include polyalkylene succinates such as polyethylene succinate, polybutylene succinate, and polyneopentylene succinate, polyalkylene adipates such as polyethylene adipate, polybutylene adipate, and polyneopentylene adipate, Examples thereof include polyoxycarboxylic acids such as polyglycolic acid, polylactic acid and polymalic acid, and polylactones such as polypropiolactone and polycaprolactone.

  Examples of engineering plastics include polyester resins, polyamide resins, polyimide resins, polyphenylene ether resins, polyphenylene sulfide resins, and the like. Of these, thermotropic liquid crystal polymers having a melt anisotropy (liquid crystal polyester resins, liquid crystal polyamide resins, liquid crystal polyester amide resins, etc.), particularly liquid crystal polyester resins are preferred. The liquid crystal polyester resin may be a polyester resin having a mesogen group (group having liquid crystal forming ability) such as a p-substituted aromatic ring, a linear biphenyl group, and a substituted naphthyl group as a structural unit. Specifically, p-hydroxybenzoic acid, a diol (such as an aromatic diol such as dihydroxybiphenyl, a C2-6 alkanediol such as ethylene glycol), an aromatic dicarboxylic acid (such as terephthalic acid) and an aromatic hydroxycarboxylic acid ( Examples thereof include copolymers with at least one monomer selected from oxynaphthoic acid and the like. More specifically, a copolymer of p-hydroxybenzoic acid and 4,4'-dihydroxybiphenyl, a copolymer of p-hydroxybenzoic acid, 4,4'-dihydroxybiphenyl and terephthalic acid, p-hydroxy Examples include copolymers of benzoic acid units and ethylene terephthalate units, and copolymers of p-hydroxybenzoic acid and 2-oxy-6-naphthoic acid. Such liquid crystal polyester resins are marketed under trade names such as “Vectra”, “Siider”, “Econol”, “X-7G”. Although the liquid crystal polymer has high mechanical properties, it has excellent melt fluidity and is therefore suitable for spinning ultrafine fibers by the method of the present invention.

  The thermoplastic resin includes various conventional additives used for fibers, such as stabilizers (antioxidants, ultraviolet absorbers, thermal stabilizers, etc.), flame retardants, antistatic agents, colorants, fillers, Contains lubricants, antibacterial agents, insect and acaricides, fungicides, matting agents, animal heat agents, fragrances, fluorescent brighteners, wetting agents, plasticizers, thickeners, dispersants, foaming agents, etc. Good. These additives can be used alone or in combination of two or more.

  Each of these additives can be used at a ratio of 50 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin, for example, a ratio of about 0.01 to 30 parts by mass, preferably about 0.1 to 20 parts by mass. It is.

  The thermoplastic resin is solid at room temperature. In addition, the solid thermoplastic resin may be melted in advance before being supplied to the heating and melting unit to be in a semisolid state or a liquid state, but a solid state is preferable from the viewpoint of simplicity and workability.

  The shape of the thermoplastic resin is not particularly limited as long as it can be melted by irradiation with a laser beam, and may be indefinite, but it is continuously supplied to the irradiation line and locally short by irradiation with the laser beam. In order to heat and melt in time, a planar body is preferable. In the planar body, the cross-sectional shape is not particularly limited, and may be a polygonal shape (triangle or square shape, etc.), an elliptical shape, an indefinite shape, etc., but a rectangular shape, a continuous sheet shape, or a tape shape. The body is preferred.

  With regard to the size of the planar body, it is easy to stably supply a sheet having a thickness of 0.05 mm or more and a width of 3 cm or more in consideration of transportability in the electrode part. The length of the planar body is not particularly limited and may be selected according to the amount of necessary fibers. For example, the length is 10 cm or more, but usually 1 m or more (for example, when continuously supplied) 1 to 1000 m).

  The means for supplying the material so as to move the material in a direction crossing the irradiation line is not particularly limited as long as the material can be moved in a predetermined direction. Usually, an electric driving force (such as rotation of a motor) is applied. An apparatus having a mechanism (for example, a mechanism for converting the rotational motion of a motor into a linear motion) that can move the material at a constant speed is used. In particular, in the case of a planar body, an apparatus having a holding portion (chuck) to which the resin can be fixed may be used. As long as the fiber can be produced, the feed rate of the material is preferably higher in terms of productivity. For example, 1 to 1000 mm / hour, preferably 5 to 500 mm / hour, more preferably 10 to 300 mm / hour ( Particularly, it is about 50 to 200 mm / hour).

  The method of applying a voltage to the melted portion of the material 9 is a direct application method in which the laser light irradiation line and the electrode portion 5 for applying the charge are matched from the viewpoint that a sufficient charge is easily supplied to the melted portion. However, the laser light irradiation line and electrode are easy to manufacture, the laser light can be effectively converted into thermal energy, the reflection direction of the laser light can be easily controlled, and the safety is high. An indirect application method (particularly, a method of setting a laser light irradiation line on the downstream side in the material supply direction) may be used in which the unit 5 is provided at a separate position. In the case of the indirect application method, it is preferable that the electrode unit 5 and the irradiation line be as close as possible. In particular, in the present invention, the material is irradiated with laser light on the downstream side of the electrode unit 5, and the electrode unit 5 It is preferable to adjust the distance between the irradiation line (for example, the distance between the downstream end of the electrode portion and the irradiation line) within a predetermined range (for example, about 5 mm to 20 mm). This distance may be set according to the electrical conductivity of the thermoplastic resin, the thermal conductivity, the glass transition point, the amount of laser beam irradiation energy, and the like, for example, 0.5 to 10 mm, preferably 5 to 8 mm, and more preferably. Is about 5 to 7 mm. When the distance between the two is set in such a range, the molecular mobility of the thermoplastic resin increases in the vicinity of the laser light irradiation line, and a sufficient charge can be imparted to the molten thermoplastic resin. Will improve.

  The voltage applied to the electrode unit 5 is preferably a high voltage within a range in which no discharge occurs in the apparatus, depending on the distance between the electrode unit 5 and the transport conveyor 8 which is a collector, the amount of irradiation energy of laser light, and the like. What is necessary is just to set suitably. Specifically, the general applied voltage is, for example, about 0.1 to 80 kV / cm, preferably 1 to 50 kV / cm, more preferably about 5 to 30 kV / cm (particularly 10 to 25 kV / cm). . In the present invention, the voltage applied to the electrode unit 5 is applied when the material 9 is melted by the laser beam, and a charge is applied to the melted portion of the material 9, and a potential difference is generated between the electrode unit 5 and the transport conveyor 8. It is only necessary to be in a state in which the above occurs. Moreover, the timing to apply is not particularly limited, but timing may be controlled so that laser light is irradiated after a voltage is applied to the electrode portion 5.

  The electrode part 5 should just be comprised with the electroconductive material (usually metal component), for example, 6A group elements, such as chromium, 8 group metal elements, such as platinum, 1B group elements, such as copper and silver, zinc, etc. 1B group elements of the above, 3B group elements such as aluminum, etc., and simple metals and alloys (aluminum alloys, stainless steel alloys, etc.), or compounds containing these metals (metal oxides such as silver oxide and aluminum oxide), etc. . These metal components can be used alone or in combination of two or more. Of these metal components, copper, silver, aluminum, stainless steel alloy and the like are particularly preferable.

  In order to efficiently charge the material 9 by the electrode part 5, the electrode part 5 has a pair of flat electrode plates arranged in parallel to each other, a passage is formed therebetween, and the plate-like material inserted into this passage A charge may be applied to 9. What is necessary is just to design the shape of the channel | path formed in the electrode part 5 according to the shape of the raw material 9 suitably.

  In the passage of the electrode portion 5, a metal wire such as a coiled metal wire or a brush-like fine metal wire assembly is arranged on the surface of the electrode plate (especially substantially over the entire surface) so that the material 9 can be easily charged. May be. As the metal material constituting the metal wire, the metal material exemplified in the electrode part 5 can be used, and usually copper, silver, aluminum, stainless steel alloy or the like is used. The metal fine wire assembly may be a metal fiber. Examples of the metal fiber include amorphous metal fiber, stainless steel fiber, super elastic NT (nickel / titanium) alloy wire, titanium wire, and the like.

  When a coiled metal wire is disposed on the surface of the pair of electrode plates, a high voltage can be easily applied to the material facing the coil. On the other hand, when the metal fine wire aggregate is disposed on the electrode plate, the metal fine wires surround the material softly and can impart electric charges to the material. It is particularly useful if the arrangement direction of the thin metal wires is set to coincide with the direction of gravity in the same manner as the supply direction of the material 9.

  When a charge is imparted to the melted portion of the material 9, the charge collects on the surface of the melted portion, and a conical (so-called tailor cone) needle-like protrusion is gradually generated at random. And it sprays toward the conveyance conveyor 8 which is a collector by the electrostatic from the front-end | tip of the produced | generated needle-like protrusion part, and becomes a fiber.

  Since a high voltage is applied to the melting part of the material 9, a potential difference is generated between the material 9 and the conveyor 8. The electric field due to the potential difference may be, for example, about 0.1 to 40 kV / cm, preferably 1 to 30 kV / cm, more preferably 5 to 25 kV / cm (particularly 10 to 20 kV / cm).

  The distance between the melted portion of the material 9 and the transport conveyor 8 as a collector is not particularly limited as long as the fiber can be heated by the heating unit 6 and whipping vibration can be imparted to the fiber. In order to produce ultrafine fibers efficiently, the thickness may be, for example, about 60 to 300 mm, preferably about 70 to 200 mm.

  The space (spinning space) between the melting part of the raw material 9 and the transport conveyor 8 may be an inert gas atmosphere. By setting the spinning space to an inert gas atmosphere, it is possible to suppress the thermal deterioration and ignition of the thermoplastic resin, so that the output of the laser beam can be increased. Examples of the inert gas include nitrogen gas, helium gas, argon gas, carbon dioxide gas, and nitrogen gas is usually used. For example, the inert gas may be supplied to the spinning space from a passage through which the material 9 is inserted by forming a flow path for supplying the inert gas to the electrode plate of the electrode unit 5. Good.

  In the present invention, in order to reduce the fiber diameter of the fiber spun from the melted portion of the material 9, the heating unit 6 is installed in the spinning space, and the spun and elongated fibers pass through the heating unit 6 to radiate heat. Heated by the wire.

  The heating unit 6 is not particularly limited as long as it has a mechanism capable of heating the fiber that is spun and stretched through the air or inert gas in the spinning space. For example, a heater (halogen heater, electric heater, etc.) is used. A mechanism for heating, a mechanism for irradiating a laser beam, or the like may be used. In the case of a heating element such as an electric heater where the heating wire is exposed, there is a risk that the apparatus may break down due to the discharge current. Therefore, a mechanism that uses a heating element such as a halogen lamp or a mechanism that irradiates a laser, particularly in terms of heating efficiency, A mechanism of heating with a halogen heater using a lamp is preferable.

  Furthermore, as a heating method, the method using hot air is preferably a method of irradiating radiant heat rays in order to inhibit the movement of the extending fiber. Further, the method of applying radiant heat rays may be a direct radiant method using a halogen lamp or the like, or a method of circulating an insulating heat medium through a ceramic electrical insulating tube. Therefore, it is preferable to provide a heat storage block for radiant heating, which is heated by a heating body such as a halogen lamp and irradiated with radiant heat rays. In addition, in the method using such a heat storage block, the kind of heating body is not specifically limited.

  When using a cylindrical lens to irradiate the material surface with a line-shaped laser beam, heat is stored during the formation of the line-shaped laser beam, taking into account the focal length of the cylindrical lens and the laser beam diameter expanded by the beam expander. The shape of the heat storage block, the focal length of the cylindrical lens, and the position of the halogen lamp must be set so that the block does not block the laser beam. In particular, care must be taken when using a long line-shaped laser beam.

  The heating temperature in the heating unit 6 may be a temperature lower than the ignition point of the thermoplastic resin, but in order to promote whipping vibration and form ultrafine fibers, the heating temperature is set near the melting point of the thermoplastic resin. Is preferred. The heating temperature in the vicinity of the melting point of the thermoplastic resin varies depending on the type of thermoplastic resin, melt viscosity, heat resistance stability, etc., and thus cannot be determined uniformly. Specifically, the melting point of the thermoplastic resin is mp (Mp−70) ° C. to (mp + 100) ° C., preferably (mp−50) ° C. to (mp + 80) ° C., more preferably (mp−30) ° C. to (mp + 60) ° C. [particularly ( mp) ° C. to (mp + 50) ° C.]. Heating a fiber that elongates at such a heating temperature has not only the advantage of maintaining the fluidity and thinning of the thermoplastic resin, but also has the effect of spreading the charge further to the tip of the fiber. That is, although the thermoplastic resin in a solid state has a large electric resistance as a general physical property, the electric resistance is lowered by bringing the thermoplastic resin into a molten state by setting the atmosphere temperature of the heating unit 6 to be close to the melting point of the thermoplastic resin. be able to. As a result, the electric charge injected into the material by the application of voltage in the electrode portion 5 further reaches the tip of the fiber on the collector side.

  Moreover, it is preferable that the heating unit 6 has a heating space through which fibers can pass, and changes depending on the heating temperature and the type of heat rays, but the length in the passage direction of the fibers in the heating space (fibers extend). Direction (usually the length in the direction of gravity) is preferably such that the fiber can pass 30 mm or more. In particular, when a passing distance of at least 30 mm or more is set in an atmosphere near the melting point of the thermoplastic resin, the temperature can be stably controlled in the atmosphere near the melting point. In addition, when the above-mentioned heat storage block is used, the atmosphere near the melting point can be adjusted by measuring the ambient temperature with a temperature sensor such as a thermocouple at the fiber passing portion and controlling the temperature of the heat storage block.

  The length of the heating space is not particularly limited as long as it is 30 mm or longer, but may be, for example, 30 to 300 mm, preferably about 35 to 200 mm from the viewpoint of workability.

  The width of the heating space of the heating part (distance perpendicular to the direction in which the fibers extend) is such that the shortest distance between the inner wall forming the heating space and the extending fibers is, for example, 20 to 400 mm, preferably May be set to a width of about 25 to 200 mm, more preferably about 30 to 100 mm (particularly 35 to 60 mm). In the present invention, if the shortest distance is too narrow, the fibers are easily collected on the inner surface of the heating unit (such as a heat storage block) or come into contact with the fiber and the whipping vibration is likely to be inhibited.

  The distance between the melting part of the raw material 9 and the heating part 6 (for example, the distance between the tip of the melting part and the upper end of the heating part 6) is, for example, 50 mm or less, preferably 1 to 30 mm, more preferably 3 About 20 mm.

  The fiber heated by the heating unit 6 performs whipping vibration. The number of vibrations of whipping vibration (motion) is, for example, 100 times / second or more (for example, 100 to 100,000 times / second), preferably 150 times / second or more (for example, 150 to 10,000 times / second), and more preferably 200 times. Times / second or more (for example, 200 to 5000 times / second). In the present invention, the diameter of the extending fiber can be reduced to a nanometer size by whipping the fiber at such a high frequency. If it is less than 100 times per second, it is difficult to form an appropriate fine fiber.

  The whip-vibrated fiber extends while flying in a spiral from the middle of flight. The amplitude of the fiber stretched by the whipping vibration (that is, the radius of the fiber aggregate deposited on the conveyor 8 as a collector) is, for example, 10 mm or more (for example, 10 to 100 mm), preferably 15 mm or more (for example, 15 to 15). 50 mm), more preferably about 20 mm or more (for example, 20 to 40 mm).

  The observation of whipping can be clearly observed when the number of thermoplastic resins (particularly linear resins) is one. The fibers that elongate while rotating spirally by whipping vibration spread in a substantially disk shape and are collected by the collector. The quantification of the whipping vibration can be measured by a device such as a high-speed video camera, but may be calculated from the state of the fiber aggregate accumulated in the collector. Specifically, since the average fiber length can be calculated from the average diameter of the ultrafine fibers and the weight of the fiber aggregate per unit time supplied to the collector, the average fiber length per second is formed on the collector. Dividing by the approximate disk-shaped circumference length, the minimum frequency Hz (times / second) is obtained, and dividing by twice the approximate disk-shaped minor diameter, the maximum frequency Hz (times / second) is obtained, Calculated as the average of both. When the whipping motion is large and the accumulated fiber aggregate has a large substantially disk-shaped area, a preferable ultrafine fiber can be obtained.

  The collector (fiber collecting unit) can be selected according to the use of the collected fibers, and examples thereof include a flat plate (for example, a fixed flat plate, a rotating disk), a rotating drum, and a belt conveyor. For example, when producing continuous fibers (filaments), a rotating disk may be used, and when producing a fiber assembly, a rotating drum or a belt conveyor may be used. Among fiber assemblies, a belt conveyor may be used when producing a mat-like fiber deposit, and a rotating drum with a traverse mechanism may be used when producing a cylindrical fiber deposit. . Furthermore, when the rotational speed of the rotating disk or drum is increased, the fiber arrangement is improved and high-performance fibers can be obtained.

  In particular, since ultrafine fibers are spirally stretched by whipping vibration from the middle of flight, when manufacturing a fiber assembly such as a nonwoven fabric, it is a twill that can be moved back and forth and left and right from the point of forming a fiber assembly of uniform density. It is preferable to use a collector having a swing mechanism. A collector having such a traversing mechanism corresponds to, for example, a frequency of 1/3000 times or less (for example, about 1/3000 to 1 / 10,000 times) the whipping frequency of a fiber that is whipping. By collecting the fibers by moving them back and forth and left and right at a low frequency, it is possible to uniformly stack the fiber aggregates that are accumulated in a substantially disk shape.

  In the present invention, a continuous long fiber can be obtained by heating and melting with a line-shaped laser beam while continuously supplying a plate-like material, and a filament having a fiber length of 100 mm or more or a uniform fiber assembly A body (nonwoven fabric having a uniform density distribution) can be obtained.

  The distance between the lower end of the heating unit 6 and the collector is only required to be a space that can spirally move while whipping vibration and thin the fiber, and is, for example, 30 mm or more (for example, 30 to 300 mm), preferably 50. It is about -200 mm, More preferably, it is about 80-150 mm.

  When a high voltage is applied between the collector and the electrode unit 5, the collector may be grounded (grounded) from the viewpoint of the handleability of the collected fibers.

  In the fiber manufacturing apparatus described above, in the electrostatic spinning process, the surface of the material 9 is irradiated with a line-shaped laser beam, heated and melted along the irradiation line, and a voltage is applied to the material 9 to charge and melt the melted portion. A needle-like protruding portion is generated from the surface by electrostatic force, and the fiber is spun from the tip of the needle-like protruding portion. By adjusting the output of the laser beam to be irradiated so that the density of the needle-like protrusions is at least 2 per 2 cm in width and applying a high voltage to increase the density of the needle-like protrusions, it is efficient Electrospinning becomes possible. In order to further elongate a large number of fibers spun from the needle-like protrusions, they are collected on the belt surface of the conveyor 8 as a collector by electrostatic force while being heated by radiant heat rays and whipped in the heating unit 6.

  In the electrospinning process, the material is charged with a charge having a polarity opposite to that of the collector, and the molten resin is removed from the needle-like protrusion using the potential difference generated between the melted portion of the material and the collector. Fly towards the collector. The fibers that fly and stretch toward the collector are heated in an atmosphere near the melting point of the thermoplastic resin, and fly and repeat stretching while repeating whipping vibrations to form ultrafine fibers. It is collected.

  As a method of applying a voltage to the melting portion of the material, for example, when the material is a planar body, the planar body is inserted into a passage formed between a pair of flat brush electrode plates arranged in the electrode portion. Thereby, an electric charge is provided to the planar body. Either the positive electrode or the negative electrode may be used as the charging polarity of the material, and electrostatic spinning is performed by an electrostatic force with a collector charged to a reverse polarity. Usually, the raw material is charged to the positive electrode, and the conveyor as a collector is charged to the negative electrode.

  In the above-described embodiment, in the electrostatic spinning process, a high voltage is applied from the high voltage application device 4 between the electrode unit 5 and the transfer conveyor (collector) 8, and the electrode unit 5 is charged to the positive electrode. The collector 8 is charged to the negative electrode. Since the material 9 is inserted into the passage of the electrode unit 5, the material 9 is positively charged through the electrode unit 5. When the material 9 is heated and melted in the irradiation line, the melted portion is charged to the positive electrode. For this reason, the fibers extend and fly toward the collector 8 charged to the negative electrode.

  In the heating and melting step, the plate-like material 9 is inserted into a passage formed between the plate-like electrode plates of the electrode portion 5 and continuously supplied so as to cross the irradiation line. On the inner surface of the electrode plate of the electrode part 5, a copper fine wire aggregate is disposed. The material 9 is charged by applying a high voltage to the electrode part 5. In the irradiation line, a line-shaped laser beam generated by the optical system 2 based on the laser beam emitted from the laser beam generator 1 is irradiated onto the material 9 and heated and melted. A large number of needle-like protrusions are generated by the electrostatic force due to charging at the melted portion, and fibers 7 are formed from the generated needle-like protrusions. The formed fibers 7 are collected by the conveyor 8 by repeating whipping vibration in the heating unit 6.

  In the collection process, the fibers fly and expand spirally while repeating the whipping vibration, and are collected by the collector 8.

  FIG. 3 is a schematic configuration diagram relating to another embodiment of the present invention. 11 is a laser beam generator, 12 is an optical system, 13 is a line-shaped laser beam, 14 is a high voltage applying device, 16 is a heating unit, 17 is a spun fiber, 18 is a conveyor (collector), The description is omitted because it is the same as that shown in FIG.

  In this example, a cylindrical body made of a thermoplastic resin material is used as the material 19. The material 19 is constantly rotated by a drive motor (not shown) with the central axis as a rotation axis, and the material 19 is moved up and down by the lifting device 20 so as to cross the irradiation line. An electrode portion 15 made of a conductive brush is disposed close to the peripheral surface of the material 19, and a high voltage is applied to the electrode portion 15 by a high voltage application device 14.

  An irradiation line is set along an axial straight line passing through the lowest position on the peripheral surface of the material 19, and the linear laser beam 13 is irradiated from the optical system 12 along the tangential direction toward the irradiation line. . Since the material 19 is always rotated, the peripheral surface of the material 19 is continuously supplied to the irradiation line, and is heated and melted by the line-shaped laser light to generate a melted portion.

  The material 19 is charged when a high voltage is applied by the electrode portion 15, and a predetermined potential difference is set between the material 19 and the grounded conveyor 18. Therefore, an electrostatic force acts on the melted portion of the material 19 to generate a large number of needle-like protrusions, and the fibers 17 are spun from the needle-like protrusions so as to be drawn to the transport conveyor 18.

  The spun fibers 7 are heated by the radiant heat rays when passing through the heating unit 16, are expanded while being whipped, and are collected by the transport conveyor 18. When the material 19 is heated and melted and decreases in the radial direction, the lifting device 20 is operated to move the material 19 downward so that the peripheral surface of the material 19 is always set in the irradiation line. Fibers can be spun continuously from 19 melting sites.

  By the spinning method described above, fibers, particularly ultrafine fibers having a small fiber diameter can be obtained. The average fiber diameter of the ultrafine fibers is, for example, 5 μm or less, and preferably about 100 nm to 3 μm. The ultrafine fiber having such an average fiber diameter may include, for example, a fiber having a fiber diameter of about 50 to 1000 nm (particularly 100 to 500 nm). Furthermore, by adjusting the kind of thermoplastic resin, production conditions, and the like, it is possible to obtain ultrafine fibers having a uniform nanometer size. The ultrafine fibers obtained by the present invention are collected by generating whipping vibration. Therefore, unless a special sampling method such as a high-speed rotating drum is selected, the ultrafine fibers constituting the sheet-like nonwoven fabric have an inverted portion (folded portion). It is a feature.

  Further, in the present invention, even if it is a biodegradable plastic for which it is difficult to select a solvent or an engineering plastic having a high melting point, ultrafine fibers can be obtained by a simple method. In particular, it is suitable for spinning a liquid crystal polymer having a melt anisotropy, which has conventionally had a high melting point and was difficult to obtain nano-sized ultrafine fibers by a normal melt spinning method. It is possible to produce ultrafine fibers (nanofibers) having a fiber diameter of 1 μm or less. Furthermore, the fiber which has a wide fiber diameter can be manufactured by adjusting the energy output of a laser beam.

  The fiber length of the fiber is not particularly limited and may be selected depending on the application by adjusting the production conditions and the like. For example, the average fiber length is 0.5 mm or more, and is used as a fiber aggregate such as a nonwoven fabric. In some cases, it may be about 1 to 50 mm, preferably 2 to 30 mm, more preferably about 3 to 10 mm. In addition, although an ultrafine fiber is generally obtained as a fiber assembly, in the present invention, since a continuously supplied material is irradiated with laser light, it can also be obtained as a multifilament fiber having an average fiber length of 100 mm or more. . In this case, a continuous multifilament yarn having an average fiber length of, for example, 150 mm or more, preferably 200 mm or more (for example, about 200 to 1000 mm) may be used.

  By the spinning method described above, a fiber assembly composed of ultrafine fibers including nanofibers (particularly, continuous nanometer-sized ultrafine fibers) can be obtained, but a fiber assembly having a high degree of dispersion in fiber diameter can also be produced. is there. For example, in such a fiber assembly, the difference between the maximum fiber diameter and the minimum fiber diameter is, for example, about 200 nm to 5 μm, preferably 300 nm to 4 μm, more preferably 400 nm to 3 μm (particularly 500 nm to 2 μm). Also good.

  Such a fiber assembly is usually a non-woven fabric (a mat-like deposit, a cylindrical deposit, etc.). Nonwoven fabrics can be obtained by conventional methods such as a method using a binder, partial hot-pressure fusion (such as hot embossing), mechanical compression (needle punching), entanglement (such as hydroentanglement) A plurality of non-woven fabrics can be bonded and laminated using the method. In addition, the non-woven fabric is within a range that does not impair the effect of the ultrafine fiber of the present invention (for example, about 0.1 to 50% by mass, preferably about 1 to 30% by mass), and other fibers (synthetic fibers, semi-synthetic fibers, recycled) Fiber, natural fiber, etc.).

  In the case of laminating with a base fabric composed of other fibers, the base fabric having electrical leakage is more easily laminated in a sheet form. As a measure of electrical leakage, sputtering or vapor deposition of a conductive metal may be used, but a normal static electricity antistatic processing level may also be used. If it does not have any electrical leakage performance, it tends to be difficult to accumulate in a sheet form due to charging repulsion. Examples of the base fabric include woven and knitted fabrics, braids (which may be hollow with nets, nets, laces, etc.), non-woven fabrics (for example, spunbond non-woven fabrics), and the shape is usually a sheet. Or it is a film form.

In the case of a laminate with a non-woven fabric or a base fabric, the form is usually a sheet, and the thickness may be appropriately selected according to the use, and can be selected from a range of about 0.01 to 100 mm. It is about 0.02 to 30 mm, preferably about 0.03 to 10 mm. Furthermore, although the fabric weight of a nonwoven fabric can also be selected according to a use, it is about 5-500 g / m < ² >, for example, Preferably it is 10-300 g / m < ² >, More preferably, it is about 20-100 g / m < ² >.

  The obtained filaments and fiber aggregates may be subjected to post-processing treatment such as electrification processing, hydrophilization treatment by plasma discharge treatment or corona discharge treatment, and further secondary processing depending on the purpose. .

  In the embodiment described above, the material is supplied in the form of a planar body and a cylindrical body. However, for the supply of the planar body material, a plurality of planar bodies made of different types of resin materials are simultaneously irradiated. It may be supplied to a line, melted separately and electrostatically spun and then collected to obtain a fiber assembly. In addition, as a raw material, a fiber material in which a plurality of types of linear bodies are pre-composited, or a linear fiber material in which a plurality of different types of materials are separately made into fiber materials are aligned and fixed with a warp machine or the like to form a sheet The obtained fiber assembly may be heated and melted at the same time as a flat sheet material and electrostatically spun to obtain a fiber assembly composed of composite fibers.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. The fiber diameter in the examples was measured by the following method.

[Measurement method of fiber diameter]
An aluminum foil cut to about 30 mm square was placed on the collector, melted electrospinning was performed under various conditions, and the fiber deposit produced on the aluminum foil was gold sputter coated. An image of this coating is taken with a scanning electron microscope (SEM; KEY-9800, manufactured by Keyence Corporation), and arbitrarily selected 30 fibers that can be seen on the computer screen. (Adobe, Photoshop CS3 Extended) and the average value and standard deviation were determined.

[Example 1] (Electrostatic spinning of methyl methacrylate polymer)
A flat sample having a length of 70 mm and a width of 30 mm was obtained from a methyl methacrylate polymer (Acrylite, manufactured by Mitsubishi Rayon Co., Ltd., thickness: 3.0 mm). Ultrafine fibers were produced based on the melt-type electrospinning apparatus described with reference to FIG.

  The plate-like sample was conveyed downward at a constant speed (10 mm / h) by the rotation of the supply roller, and continuously supplied toward the irradiation line.

  In the electrode part, a pair of brass plate electrodes are disposed, and a high voltage is applied by a high voltage generator (manufactured by Matsusada Precision Co., Ltd., HARb-60P1). Then, when the flat sample passes through between the electrode plates while being transported downward, an electric charge is applied to the flat sample.

As a laser beam generator, a carbon dioxide laser beam generator (manufactured by Sinrad, RF-excited CO ₂ laser, wavelength: 10.2 to 10.8 μm, rated output: 10 W, beam diameter: 3.5 mm) is used. A beam expander (ULO Optics / Hakuto Co., Ltd., C-BE 7.0) and a cylindrical convex lens (Furukawa Electronics, f300 mm) were used as an optical system for generating laser light. By irradiating the obtained plate-shaped laser beam (L = 30 mm, t = 3 mm) to the plate-like body sample, the plate-like body sample was heated and melted along the irradiation line. The distance between the electrode part and the irradiation line was set to 10 mm.

  As a heating unit, a pair of heat storage blocks for radiation heating (a heat storage block manufactured by processing a ceramic to a thickness of 5 mm, a width of 50 mm, and a height of 30 mm) is prepared, and the width direction is perpendicular to the collector and perpendicular to the spinning direction. In addition, a width of 40 mm was maintained in parallel between the irradiation line and the collector so that the height direction was the spinning direction. However, the distance between the irradiation line and the upper end of the heat storage block was set to 15 mm, and the distance between the lower end of the heat storage block and the collector was set to 30 mm. The installed heat storage block is heated with two halogen lamps (USHIO Inc., spot heater “UL-SH-02”), and the ambient temperature (Ts) of the heating space through which the fiber surrounded by the heat storage block passes. ) Was controlled by changing the heater voltage.

  As a collector for collecting fibers, a collector (XY stage, manufactured by Kato Tech Co., Ltd.) capable of traversing back and forth and right and left was used. However, in Example 1, this collector was in a stationary state.

  At collector distance (irradiation line-collector distance) of 75 mm, laser output (Lp) of 10 W, and central part of heating part (passing distance is 30 mm and central part of heating space located at a distance of 20 mm from heat storage block wall) When the experiment was conducted with the heating atmosphere temperature (Ts) fixed at room temperature, the sample was heated and melted by the laser beam in the irradiation line, and a needle-like protrusion was formed from the melted site, so that a plurality of fibers were placed on the lower collector. It was spun toward. FIG. 4 is a graph showing the relationship between the diameter of the spun fiber and the applied voltage (Hv). From this experimental result, it can be seen that the fiber diameter decreases as the applied voltage increases. Furthermore, although some fibers had an average fiber diameter of around 2 μm, fibers having a diameter of 1 μm or less were partially obtained.

[Example 2] (Melt-type electrospinning of ethylene-vinyl alcohol copolymer resin)
Eval (ethylene-vinyl alcohol copolymer resin, manufactured by Kuraray Co., Ltd., F grade) using a hot press (GONNO HYDRAULIC PRESS MANUFACTUING, TON PRESS), a flat plate with a thickness of 1.5 mm and a length of 70 mm A sample was obtained. The production conditions are a melting temperature of 200 ° C. and a pressure of 5 MPa. An experiment was performed with the same apparatus configuration as in Example 1 using the prepared flat sample.

  FIG. 5 shows a collector distance of 75 mm, a laser output (Lp) of 10 W, an applied voltage (Hv) of 30 kV, and a heating atmosphere temperature (Ts) of room temperature, 50 ° C., 70 ° C., 90 ° C., 110 ° C., 130 It is the graph which changed the temperature with 150 degreeC and 180 degreeC, and showed the relationship with a fiber diameter. From this experimental result, it can be seen that ultrafine fibers can be obtained with stable whipping vibration even in the temperature range exceeding the melting point.

[Example 3] (Melting type electrospinning of Vectra L920)
A flat plate sample having a thickness of 1.5 mm and a length of 70 mm or more was obtained from a Vectra (polyplastics Co., Ltd., grade L920) chip using a hot press (manufactured by GONNO HYDRAULIC PRESS MANFACTING, TON PRESS). The production conditions are a melting temperature of 315 ° C. and a pressure of 5 MPa. An experiment was performed with the same apparatus configuration as in Example 1 using the prepared flat sample.

  FIG. 6 is a graph showing the relationship between the fiber diameter and the heating atmosphere temperature (Ts) changed to room temperature, 100 ° C., 220 ° C., and 300 ° C. under the same conditions as in Example 2. From this experimental result, it can be seen that the fiber diameter decreases as the heating atmosphere temperature increases, and ultrafine fibers can be obtained.

[Example 4] (Melt type electrospinning of semi-aromatic polyamide diameter resin)
Polyamide 9MT (Polynonanediamine terephthalamide, manufactured by Kuraray Co., Ltd., Genesta, melting point 270 ° C.) using a hot press (manufactured by GONNO HYDRAULIC PRESS MANUFACTUING, TON PRESS), thickness 1.5 mm, length 70 mm or more A flat plate sample was obtained. The production conditions are a melting temperature of 300 ° C. and a pressure of 5 MPa. An experiment was performed with the same apparatus configuration as in Example 1 using the prepared flat sample.

  FIG. 7 is a graph showing the relationship between the fiber diameter and the heating atmosphere temperature (Ts) changed to room temperature, 100 ° C., 150 ° C., 200 ° C., 270 ° C., 300 ° C., and 330 ° C. under the same conditions as in Example 2. It is. From this experimental result, although some fibers had an average fiber diameter of about 2 μm, fibers having a diameter of 1 μm or less were partially obtained.

  The ultrafine fiber obtained by the method of the present invention is excellent in flexibility and has a large surface area, and thus is excellent in various properties such as liquid absorption and filterability. Moreover, it is more suitable for the product of the field | area where inclusion of a solvent is disliked. Therefore, for various uses, for example, electronic parts such as separators for insulating materials, industrial materials (oil adsorbents, leather base fabrics, compounding materials for cement, compounding materials for rubber, various tape base materials, air filters, liquid filters, etc. ), Medical / hygiene materials (paper diapers, gauze, bandages, medical gowns, surgical tape, etc.), life-related materials (wipers, printed materials, packaging / bag materials, storage materials, filters, etc.), clothing materials, interior materials (heat insulation) Materials, sound-absorbing materials, etc.), construction materials, agricultural / horticultural materials, civil engineering materials (soil stabilizers, filtration materials, sand flow prevention materials, reinforcing materials, etc.), bags, shoes, etc.

  In particular, ultrafine fibers composed of biodegradable plastics are suitable for medical or agricultural fields where high performance is required. For example, non-woven fabrics are tissue medical engineering materials (artificial membranes), scaffolds for cell proliferation. It can be used for materials and the like, and the filaments or cylinders can be used for artificial blood vessels. Nonwoven fabrics made of ultrafine fibers made of engineering plastics are used in electronics fields such as battery separators (nickel-cadmium batteries, nickel-hydrogen batteries, lithium secondary batteries, alkaline secondary batteries, etc.) and capacitor separators. Can be used.

It is a schematic block diagram regarding embodiment of this invention. It is a schematic diagram regarding the fusion | melting site | part formed in the lower end part of a raw material. It is a schematic block diagram regarding another embodiment of this invention. 4 is a graph showing a relationship between an applied voltage (Hv) obtained in Example 1 and a fiber diameter. 4 is a graph showing the relationship between the heating atmosphere temperature (Ts) obtained in Example 2 and the fiber diameter. 4 is a graph showing the relationship between the heating atmosphere temperature (Ts) obtained in Example 3 and the fiber diameter. 6 is a graph showing the relationship between the heating atmosphere temperature (Ts) obtained in Example 4 and the fiber diameter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser beam generator 2 Optical system 3 Line-shaped laser beam 4 High voltage application apparatus 5 Electrode part 6 Heating part 7 Fiber 8 Conveyor (collector)
9 materials
10 Supply roller
11 Laser beam generator
12 Optical system
13 Line-shaped laser light
14 High voltage application device
15 Electrode section
16 Heating section
17 Textile
18 Conveyor (collector)
19 material
20 Lifting device

Claims (11)

  Laser light emitted from a light source is irradiated along a predetermined irradiation line, and the material made of a thermoplastic resin material is continuously heated and melted in the irradiation line while moving the material across the irradiation line, and heated. A spinning method comprising charging a melted part of the melted material to generate a large number of needle-like protrusions by electrostatic force and spinning the fibers from the needle-like protrusions.   The laser beam is irradiated over the entire width in the width direction of the sheet-like material to melt by heating, and two or more acicular protrusions are generated per 2 cm width of the irradiation line. The spinning method described in 1.   The laser beam is irradiated over the entire length along the axial direction of the columnar material to melt by heating, and two or more needle-like protrusions are generated per 2 cm width of the irradiation line. The spinning method described in 1.   The spinning method according to any one of claims 1 to 3, wherein the spun fiber is heated by irradiation with radiant heat rays and elongated and thinned by whipping vibration.   The spinning method according to claim 4, wherein the spun fiber is whipped at a frequency of 100 times / second or more.   The spinning method according to any one of claims 1 to 5, wherein a width of a laser light irradiation range in the irradiation line is 0.5 mm or more.   A fiber production method comprising forming a fiber assembly by collecting fibers spun by the spinning method according to any one of claims 1 to 6 and stacking them on each other.   A laser irradiation unit that controls to irradiate laser light emitted from a light source along a predetermined irradiation line, and a material made of a thermoplastic resin material is moved across the irradiation line, and the material is moved along the irradiation line. Spinning, in which a moving part is continuously heated and melted, and a plurality of needle-like protrusions are generated by electrostatic force by charging the melting part of the heated and melted material, and fibers are spun from each needle-like protrusion. And a collecting unit for collecting the spun fibers.   The said spinning part is equipped with the electrode part arrange | positioned close to the said fusion | melting site | part, and the voltage application part which applies a voltage between the said electrode part and the said collection part, The Claim 8 characterized by the above-mentioned. The fiber manufacturing apparatus as described.   10. The fiber according to claim 8, further comprising a heating unit that heats the fiber spun from the needle-like projecting portion with a radiant heat ray between the electrode unit and the collecting unit. Manufacturing equipment.   The said collection part collects the spun fiber by a collector, and forms a fiber assembly by mutually superposing | stacking, The fiber manufacturing apparatus characterized by the above-mentioned.

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