JP6496120B2 - High melting point resin fiber and nonwoven fabric - Google Patents

Description

The present invention relates to a high melting point resin fiber and a nonwoven fabric using a melt type electrospinning method.
More specifically, a high melting point resin fiber and a high melting point resin fiber obtained by processing a high melting point resin (film) into ultrafine fibers having a diameter of 4 μm or less by a melt type electrospinning method (laser melting electrospinning method) using a laser beam as a heating means. It is related with the nonwoven fabric which consists of.

  In recent years, fibers having a fiber diameter of submicron or nanometer order have attracted attention because they can develop new materials utilizing a large specific surface area and fiber form. As a method for producing such a fiber, for example, an electrostatic spinning method (melting type electrospinning method) in which a high voltage is applied to a polymer melt to form a fiber has been proposed.

  As the melt-type electrostatic spinning method, for example, in Patent Document 1, a heating and melting step in which a thermoplastic resin is heated and melted by irradiating a laser beam, and a fiber that stretches by applying a voltage to a melting portion of the thermoplastic resin. A melt-type electrospinning method (laser melt electrospinning method) has been proposed in which fibers are produced through an electrospinning process in which a collector is collected. In this method, a linear resin is used as the spinning material, and the fiber is produced by discharging the fiber from its tip.

  Moreover, in patent document 2, using the said laser melting electrospinning method, while irradiating a linear laser beam to the sheet-like material which consists of a thermoplastic resin, the edge part of the said sheet-like material is heated and melted linearly. By providing a potential difference between the melted portion and the metal collector, a needle-like protrusion is formed in the heated and melted portion of the sheet-like material, and the fibers discharged from the needle-like protrusion are directed in the metal collector direction. It is made to fly and collected on a metal collector or a collecting member interposed between the molten portion and the metal collector.

  High melting point resins such as polyetheretherketone (PEEK), polyphenylene sulfide (PPS), and polyamideimide (PAI) have heat resistance, flame resistance, chemical resistance, and impact resistance, and are also called super engineering plastics It is widely used in the automotive and electrical / electronic fields. Among them, PEEK is an aromatic plastic having a melting point of 334 ° C. and super heat resistance that can be continuously used at 250 ° C., and has the highest heat resistance as a thermoplastic resin and chemical resistance to an organic solvent.

  As a method for converting these high melting point resins into fibers (fibers), a technique such as melt blown is known, but the diameter of the fibers is several μ to several tens μm, and it is possible to obtain finer nanofibers. Have difficulty. In addition, as a technique for obtaining finer nanofibers, a technique such as electrospinning is known, but super engineering plastics having a high melting point such as PEEK are often insoluble in organic solvents and the like. I can't.

JP 2007-239114 A JP 2010-275661 A

  On the other hand, in the laser melting electrospinning method of Patent Document 2, the crystallinity of the raw material film is not controlled, and if the crystallinity is high, it is difficult to increase the processing speed. The obtained fiber had a diameter of 5 μm or more. Furthermore, the degree of crystallinity of the obtained fiber was high, and it was difficult to process and mold it.

  Accordingly, an object of the present invention is to provide a high-melting point resin fiber having a diameter of 4 μm or less and a non-woven fabric made of a high-melting point resin fiber, which has heat resistance and solvent resistance and excellent workability. Another object of the present invention is to provide a method for producing a high-melting point resin fiber having a diameter of 4 μm or less by using a laser melting electrospinning method.

  Therefore, as a result of intensive studies by the present inventors to achieve the above object, a high melting point resin having a diameter of 4 μm or less is obtained by using an amorphous resin as a polymer sheet as a raw material in the laser melting electrospinning method. A fiber was obtained, and it was found that a fiber having heat resistance and solvent resistance was obtained by thermoforming the fiber produced thereby, and the present invention was completed.

  That is, the high melting point resin fiber of the present invention is characterized by comprising a resin having a diameter of 4 μm or less and a melting point of 250 ° C. or more.

  In the high melting point resin fiber of the present invention, the resin having a melting point of 250 ° C. or higher is preferably PEEK.

  The high melting point resin fiber of the present invention preferably has a crystallinity of 30% or less.

  In the method for producing a high melting point resin fiber of the present invention, a polymer sheet made of an amorphous high melting point resin is irradiated with a band-shaped laser beam to heat and melt the end portion of the polymer sheet in a linear shape and melt. By providing a potential difference between the belt-like melted portion and the fiber collecting plate, a needle-like projecting portion is formed in the belt-like melted portion of the polymer sheet, and fibers discharged from the needle-like projecting portion are collected in the fiber. A high melting point resin fiber is obtained by flying in the plate direction and collecting on the fiber collecting plate or a collecting member interposed between the molten portion and the fiber collecting plate.

  Moreover, it is preferable that the manufacturing method of the high melting point resin fiber of this invention is 2-20 mm / min in the feed rate of the said polymer sheet.

  Moreover, it is preferable that the said electrical potential difference is 0.1-30 kV / cm in the manufacturing method of the high melting point resin fiber of this invention.

  Moreover, the manufacturing method of the high melting point resin fiber of this invention is that the viscosity at the time of the shear rate (shear rate) 121.6 (1 / s) of the said polymer sheet measured at 400 degreeC is 800 Pa.s or less. Is preferred.

  The nonwoven fabric of the present invention is obtained from the high melting point resin fiber of the present invention.

  Since the high melting point resin fiber of the present invention has a low crystallinity, it is excellent in workability, and since a high melting point resin such as PEEK is used as a material, it is excellent in heat resistance and chemical resistance. In addition, non-woven fabric using this is made of very fine fibers, has excellent separation ability when used as a battery separator or a filter for medical materials, and is made of a high melting point resin such as PEEK. Excellent in heat resistance, chemical resistance and chemical resistance.

It is the schematic which shows typically an example of the manufacturing method of the high melting point resin fiber of this invention. It is a schematic diagram of the tailor cone formed in a belt-shaped melted part. It is sectional drawing which shows typically an example of the nonwoven fabric manufacturing apparatus containing the manufacturing method of the high melting point resin fiber of this invention.

[High melting point resin fiber]
The high melting point resin fiber of the present invention is an ultrafine fiber having a small fiber diameter, and its diameter is 4 μm or less. The diameter of the fiber is preferably 3 μm or less (0.1 to 3 μm), more preferably 2 μm or less. In addition, the ultrafine fiber having such a diameter may include, for example, a fiber having a fiber diameter of about 50 to 1000 nm. And the diameter of a fiber can be adjusted by adjusting suitably various conditions (for example, the thickness of a polymer sheet, the feeding speed of a polymer sheet, laser intensity, etc.) of the high melting point resin fiber manufacturing method mentioned below. . The diameter of the high melting point resin fiber can be measured using, for example, an electron microscope.

  The high melting point resin fiber of the present invention comprises a resin having a melting point of 250 ° C. or higher. The melting point of the high melting point resin fiber is preferably 260 ° C. or higher, more preferably 270 ° C. or higher, and further preferably 280 ° C. or higher. Such a resin having a melting point of 250 ° C. or higher is not particularly limited. For example, polyether ether ketone (PEEK) (melting point 334 ° C.), polyphenylene sulfide (PPS) (melting point 290 ° C.), polyamideimide (PAI) (Melting point: 300 ° C.), polytetrafluoroethylene (PTFE) (melting point: 327 ° C.), silicon resin (melting point: about 300 ° C.), fluororesin (melting point: 327 ° C.), liquid crystal polymer (melting point: 260-300 ° C.), and the like. Among them, PEEK is preferable because of its high melting point and excellent heat resistance and solvent resistance.

  The high melting point resin fiber of the present invention preferably has a crystallinity of 30% or less. The crystallinity is more preferably 29% or less, and even more preferably 28% or less. When the degree of crystallinity is 30% or less, it is excellent in processability and can be easily formed into a nonwoven fabric, a filter, a separator, or the like. The crystallinity can be determined by, for example, an X-ray diffraction method, DSC (differential scanning calorimeter) measurement, density method, or the like. In the present application, the degree of crystallinity was calculated from the amount of heat obtained from DSC measurement by the method described in Examples.

  Moreover, it is preferable that the high melting point resin fiber of this invention is obtained by the manufacturing method of the below-mentioned high melting point resin fiber, using an amorphous high melting point resin as a raw material as a polymer sheet.

  The thickness of the non-crystalline high melting point resin (sheet) that is a polymer sheet is, for example, 0.01 to 10 mm, and preferably 0.05 to 5.0 mm. When the thickness is in the above range, a high melting point resin fiber described later can be easily produced.

  The average fiber diameter of the aggregate of the high melting point resin fibers of the present invention is not particularly limited, but is preferably 4 μm or less (0.1 to 4 μm), more preferably 3 μm or less, and further preferably 2 μm or less. The average fiber diameter is obtained by, for example, photographing a plurality of (for example, 10) fiber forms using a scanning electron microscope, and arbitrarily processing the diameter of about 10 fibers per image from the photographed images. It can be obtained by measuring with and averaging them.

[Method for producing high melting point resin fiber]
The high melting point resin fiber of the present invention is preferably produced by using a laser melting electrospinning method described later. Specifically, the laser melting electrospinning method is the following method.

  The manufacturing method (laser melt electrospinning method) of the high melting point resin fiber of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view schematically showing an example of a method for producing a high melting point resin fiber. In the method for producing a high melting point resin fiber, a polymer sheet made of a high melting point resin (sheet) is irradiated with a band-shaped laser beam to heat and melt the end of the polymer sheet linearly, By providing a potential difference with the fiber collecting plate, a needle-like protruding portion is formed in the belt-like melted portion of the polymer sheet, and the fibers discharged from the needle-like protruding portion fly in the direction of the fiber collecting plate. The fiber is obtained by collecting on the fiber collecting plate or the collecting member interposed between the molten portion and the fiber collecting plate.

  In the method for producing a high melting point resin fiber, as shown in FIG. 1, a laser beam having a spot-like cross section emitted from a laser generating source 1 is adjusted to an optical path comprising a beam expander and homogenizer 2, a collimation lens 3 and a cylindrical lens group 4. After being converted into a strip-shaped laser beam 5 having a linear cross section through means, the strip-shaped melted portion 6a of the polymer sheet 6 held by the holding member 7 is irradiated and a voltage is applied by the high-voltage generator 10; A potential difference is generated between the belt-shaped melted portion 6 a and the fiber collecting plate 8 disposed on the lower side of the polymer sheet 6. Further, the temperature of the belt-shaped melted portion 6a can be observed by the thermography 9, and the conditions such as the voltage and the laser beam to be irradiated can be optimized.

  In the example shown in FIG. 1, the holding member 7 that holds the polymer sheet 6 also functions as an electrode. When a voltage is applied to the holding member 7 by the high-voltage generator 10, the polymer sheet 6 Electric charges are applied to the belt-shaped melted portion 6a. The fiber collecting plate 8 has a surface electrical resistance value comparable to that of a metal. Examples of the shape include a plate shape, a roller shape, a belt shape, a net shape, a saw shape, a wave shape, a needle shape, and a line shape. The optical path adjusting means is an assembly of optical components, and includes a beam expander and homogenizer 2, a collimation lens 3, a cylindrical lens 4 group, and the like. By using these optical path adjusting means, the spot laser beam can be converted into the band laser beam 5.

  In the example shown in FIG. 1, the irradiation with the band-shaped laser beam 5 heats and melts the band-shaped melted portion 6 a of the polymer sheet 6, and charges are added to the heat-melted portion. As shown in FIG. 2, in the belt-like melted portion 6a to which electric charges are applied, charges are collected and repelled on the surface, thereby gradually forming a plurality of needle-like protrusions (tailor cones) 6b. When the force exceeds the surface tension, the melted thermoplastic resin is discharged as fibers from the tip of the tailor cone to the fiber collecting plate 8 by electrostatic attraction, that is, fibers are formed from the needle-like protrusions 6b, and the fibers Fly in the direction of the collection plate 8. As a result, the elongated fibers are collected by the fiber collecting plate 8. Further, when a collecting member is placed on the fiber collecting plate 8, the fibers are collected on the collecting member. That is, in the method for producing a high melting point resin fiber of the present invention, the fiber collection plate itself may be a member for collecting fibers, and the collection member is placed on the fiber collection plate separately from the fiber collection plate. It may be. FIG. 2 is a schematic view of a tailor cone formed in the belt-shaped melted portion 6a.

  The number of tailor cones shown in FIG. 2 (tailor cone spacing) can be adjusted by appropriately changing the thickness of the polymer sheet 6. The development of the tailor cone means that the height of the tailor cone (h in FIG. 2) increases.

  The number of tailor cones is not particularly limited, but it is preferably 1 or more per 2 cm in the heated and melted portion of the polymer sheet, and more preferably 1 to 100/2 cm. The reason for this is that if it is 1 piece / 2 cm or less, it is not preferable from the viewpoint of the degree of uniformity of the nonwoven fabric and the amount of production, and it is better to increase it, but if it is 100 pieces / 2 cm or more, the degree of uniformity decreases due to electrical repulsion between tailor cones. It is to do. More preferably, it is 1-50 pieces / 2 cm, and particularly preferably 2-10 pieces / 2 cm.

Examples of the laser generation source include a YAG laser, a carbon dioxide (CO ₂ ) laser, an argon laser, an excimer laser, and a helium-cadmium laser. Among these, a carbon dioxide laser is preferable from the viewpoint of high power efficiency and high PEEK resin meltability. Moreover, the wavelength of a laser beam is 200 nm-20 micrometers, for example, Preferably it is 500 nm-18 micrometers, More preferably, it is about 5-15 micrometers.

  Moreover, in the manufacturing method of a high melting point resin fiber, when irradiating a strip | belt-shaped laser beam, it is preferable that the thickness of the laser beam is about 0.5-10 mm. If the thickness of the laser beam is less than 0.5 mm, it may be difficult to form a tailor cone. If the thickness is more than 10 mm, the melt residence time becomes long and the material may be deteriorated.

  The output of the laser light may be controlled in a range in which the temperature of the belt-like melted portion is equal to or higher than the melting point of the thermoplastic resin and equal to or lower than the ignition point of the polymer sheet. The higher one is preferable from the viewpoint of reducing the diameter. The specific output of the laser beam can be appropriately selected according to the physical properties (melting point, LOI value (limit oxygen index)) and shape of the thermoplastic resin to be used, the feeding speed of the polymer sheet, etc. It is about 100 W / 13 cm, preferably 20 to 60 W / 13 cm, more preferably 30 to 50 W / 13 cm. The intensity of the laser beam is the output of the spot beam emitted from the laser source.

  The temperature of the belt-like melted part is not particularly limited as long as it is not lower than the melting point of the high melting point resin and not higher than the ignition point, but is usually about 300 to 600 ° C, preferably 350 to 500 ° C.

  In the manufacturing method of the high melting point resin fiber of the present invention shown in FIG. 1, the laser beam is irradiated from only one direction to the belt-shaped melted portion (end portion) of the polymer sheet. May be irradiated to the belt-shaped melted portion (end portion) of the polymer sheet from two directions. This is because even if the thickness of the sheet-like material is large, the end portion thereof can be melted more uniformly.

  In the method for producing a high melting point resin fiber, the potential difference generated between the end of the polymer sheet and the collecting member is preferably a high voltage within a range in which no discharge occurs, and the required fiber diameter, electrode, and catching capacity. Although it can select suitably according to the distance with a collection member, the irradiation amount of a laser beam, etc., it is about 0.1-30 kV / cm normally, Preferably it is 0.5-20 kV / cm, More preferably, it is 1-10 kV / cm. cm.

  The method of applying a voltage to the melted part of the polymer sheet may be a direct application method in which the laser light irradiation part (the belt-like melted part of the polymer sheet) and the electrode part for applying electric charge are matched. The laser beam irradiation part and the charge are given from the point that the device can be easily manufactured, the laser beam can be effectively converted into thermal energy, the reflection direction of the laser beam can be easily controlled, and the safety is high. An indirect application method (particularly, a method of providing a laser beam irradiation part on the downstream side in the feeding direction of the polymer sheet) is preferred in which the electrode part is provided at a separate position. In particular, in the above manufacturing method, the polymer sheet is irradiated with a band-shaped laser beam on the downstream side of the electrode unit, and the distance between the electrode unit and the laser beam irradiation unit (for example, the lower end of the electrode unit and the upper side of the band-shaped laser beam) It is preferable to adjust the distance to the outer edge to a specific range (for example, about 10 mm or less). This distance can be selected according to the conductivity, thermal conductivity, glass transition point, laser beam irradiation amount, etc. of the PEEK resin, and is, for example, 0.5 to 10 mm, preferably 1 to 8 mm, more preferably 1.5. -7 mm, particularly preferably about 2-5 mm. When the distance between the two is in this range, the molecular mobility of the resin in the vicinity of the laser light irradiation portion is increased, and a sufficient charge can be imparted to the molten resin, so that productivity can be improved.

  In addition, the distance between the end of the polymer sheet (the tip of the tailor cone) and the collecting member is not particularly limited, and is usually 5 mm or more, but in order to efficiently produce ultrafine fibers The thickness is preferably 10 to 300 mm, more preferably 15 to 200 mm, still more preferably 50 to 150 mm, and particularly preferably about 80 to 120 mm.

  When the polymer sheet is continuously fed out, the feeding speed is not particularly limited, but is usually about 2 to 20 mm / min, preferably 3 to 15 mm / min, and more preferably 4 to 10 mm / min. If the speed is increased, the productivity increases. However, if the speed is too high, the resin in the vicinity of the laser light irradiation portion is not sufficiently melted, so that it is difficult to produce fibers. On the other hand, when the speed is low, the high melting point resin is decomposed or the productivity is lowered.

  Moreover, in the said manufacturing method, an inert gas atmosphere may be sufficient as the space between the edge part of the said polymer sheet and the said collection member. By making this space an inert gas atmosphere, the firing of the fibers can be suppressed, so that the output of the laser light can be increased. Examples of the inert gas include nitrogen gas, helium gas, argon gas, carbon dioxide gas, and the like. Of these, nitrogen gas is usually used. In addition, the use of the inert gas can suppress the oxidation reaction in the belt-like melted portion.

  The space may be heated. Thereby, the fiber diameter of the fiber obtained can be made small. That is, by heating the air or inert gas in the space, it is possible to suppress a rapid temperature drop of the fiber being formed, thereby promoting the elongation or stretching of the fiber and obtaining a finer fiber. It is done. Examples of the heating method include a method using a heater (such as a halogen heater) and a method of irradiating a laser beam. The heating temperature can be selected, for example, from a temperature range from 50 ° C. or higher to less than the ignition point of the resin, but from the viewpoint of spinnability, a temperature less than the melting point of the resin is preferable.

[Polymer sheet]
For example, the non-crystalline polymer sheet is preferably a sheet having a crystallinity of 25% or less, more preferably 20% or less, and further preferably 15% or less. When the crystallinity is 25% or less, a high melting point resin fiber having a low crystallinity can be obtained. The crystallinity of the polymer sheet can be determined by the same method as the crystallinity of the high melting point resin fiber.
Note that the term “amorphous” as used herein means that the resin has a bulky molecular chain (a molecular chain with a large steric hindrance) in the molecular skeleton, so that a regular molecular arrangement can be taken in the process of cooling and solidifying from a molten state. First, it refers to the property of becoming a random molecular arrangement even in a solidified state.

  The amorphous polymer sheet preferably has a low viscosity from the viewpoint of easily forming ultrafine fibers such as nanofibers. For example, the shear rate (shear rate) measured at 400 ° C. is 121.6 (1 / The viscosity at the time of s) is preferably 800 Pa · s or less (50 to 800 Pa · s), more preferably 600 Pa · s or less, and further preferably 400 Pa · s or less. The viscosity when the temperature is 400 ° C. can be determined by a capillary rheometer (trade name “Capillograph 1D”, manufactured by Toyo Seiki Seisakusho Co., Ltd.) by the method described in Examples. The shear rate (shear rate) can also be measured using a capillary rheometer.

  The non-crystalline polymer sheet can be produced, for example, by heating and melting a non-crystalline chip-like resin with a T-die extruder or the like to form a sheet. As the non-crystalline chip-like resin, a commercially available product can be used, and a trade name “VESTAKEEEP 1000G” (manufactured by Daicel-Evonik Co., Ltd.) can be preferably used. In addition, the heating temperature of a T-die extrusion molding machine should just be more than melting | fusing point of resin, for example, is 350-400 degreeC.

  The non-crystalline polymer sheet comprises various additives used for fibers, such as stabilizers (antioxidants, ultraviolet absorbers, heat stabilizers, etc.), flame retardants, antistatic agents, colorants, fillers. , Lubricants, antibacterial agents, insect and acaricides, fungicides, matting agents, heat storage agents, fragrances, fluorescent brighteners, wetting agents, plasticizers, thickeners, dispersants, foaming agents, surfactants, etc. You may contain. These additives can be contained alone or in combination of two or more.

  Among these additives, for example, it is preferable to use a surfactant. When a charge is injected by applying a high voltage to the polymer sheet, the polymer sheet made of a high melting point resin has high electrical insulation, and it is difficult to inject the charge to the heat melting portion where the electrical resistance is low. However, when a surfactant is used, the electrical resistance of the surface of the fiber having a large electrical insulation is lowered, and the electric charge can be sufficiently injected up to the heat melting portion. Also, the application of a surfactant or the like is effective for phase separation when the sheet is composed of a plurality of components when a high voltage is applied to the polymer sheet to inject charges.

  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 polymer sheet resin, for example, 0.01 to 30 parts by mass, preferably about 0.1 to 5 parts by mass. It is a ratio.

[Nonwoven fabric]
The nonwoven fabric of the present invention may be produced by the production method described later, or may be produced by another method of the high melting point resin fiber of the present invention.

The thickness of the nonwoven fabric of the present invention may be appropriately selected according to the use, and can be selected from the range of about 0.0001 to 100 mm, but is usually 0.001 to 50 mm, preferably 0.01 to 15 mm, and more preferably. Is about 0.05 to 1 mm. Further, the basis weight of the nonwoven fabric can be selected according to the intended use, usually about from 0.001 to 100 g / m ^2, preferably 0.05 to 50 g / m ^2, more preferably 0.1 to 10 g / m It is about ² . The nonwoven fabric of the present invention has a fiber diameter, thickness, basis weight, and other shapes of the nonwoven fabric to be manufactured by adjusting the sheet feeding speed and laser strength, the moving speed of the collecting member, etc. in the nonwoven fabric manufacturing method described below. Can be controlled.

  Further, the nonwoven fabric of the present invention may be subjected to post-processing treatment such as electrification processing, plasma discharge processing, corona discharge processing, sulfonation processing, hydrophilization processing such as graft polymerization, depending on the purpose. . Moreover, the nonwoven fabric may be further subjected to secondary processing, and may be laminated and integrated with another nonwoven fabric (for example, a spunbond nonwoven fabric), a woven or knitted fabric, a film, a plate, a substrate, and the like.

[Method for producing nonwoven fabric]
Next, an example of the manufacturing method of a nonwoven fabric is demonstrated. In the following nonwoven fabric manufacturing method, the high melting point resin fiber can be continuously manufactured while moving the collection position of the fibers flying in the fiber collecting plate direction with time.

  Here, as a method for moving the collection position of the fibers flying in the fiber collection plate direction with time, for example, (1) a collection member (when the fiber collection plate itself functions as a collection member) (2) a method of moving the holding position of the polymer sheet, (3) a mechanical, magnetic or electrical force on the flying fiber from the tailor cone toward the collecting member. For example, a method of applying a strong force, for example, a method of blowing air to a fiber in flight, (4) a method of selectively combining the methods (1) to (3), and the like can be used.

  Among these, the method of (1) above, that is, the method of moving the collecting member is easy in that the configuration of the apparatus is easy and the shape (thickness, basis weight, etc.) of the nonwoven fabric to be manufactured can be easily controlled. desirable. Hereinafter, the manufacturing method of a nonwoven fabric is explained in full detail for the case of using the method of said (1).

  In the method for producing a nonwoven fabric using the method (1), a collecting member is placed on the fiber collecting plate 8 in the producing method shown in FIG. The high melting point resin fiber of the present invention is continuously produced while moving in a direction perpendicular to the width method (right direction or left direction in the figure). Here, the moving speed of the collecting member may be constant, may change with time, and may be repeatedly moved and stopped. In order to continuously produce the high melting point resin fiber of the present invention, as already explained, the polymer sheet 6 is moved to the fiber collecting plate 8 side (collecting member) as the fiber production process proceeds. Side). In addition, the speed | rate (feed speed) which sends out a polymer sheet continuously is as having described with the manufacturing method of the high melting point resin fiber.

Moreover, the moving speed of the collection member on the fiber collection plate 8 is not particularly limited, and may be appropriately determined in consideration of the basis weight of the fiber sheet to be manufactured, but is usually about 10 to 2000 mm / min. For example, when the feeding speed of the polymer sheet having a basis weight of 1000 g / m ² is 0.5 mm / min, by setting the moving speed of the collecting member to about 1000 mm / min, the basis weight is about 0.5 g / m ² . Nonwoven fabrics can be produced continuously.

  FIG. 3 is a cross-sectional view schematically showing an example of a nonwoven fabric production apparatus including the method for producing the high melting point resin fiber shown in FIG. The apparatus shown in FIG. 3 includes a laser source 11, an optical path adjusting member 12, a polymer sheet feeding device 13 that can continuously feed the polymer sheet 6, a holding member 16 that holds the polymer sheet 6, and a polymer. The electrode 17 for imparting electric charge to the sheet 6, the collecting member 22 for collecting the fibers, the electrode 17 and the belt-like melted part (end part) 6 a of the polymer sheet 6, and the collecting member 22 are arranged to face each other. A housing 23 in which the fiber collecting plate 14 and the heating device 15 are arranged, an electrode 17, high voltage generators 20 a and 20 b that apply voltages to the fiber collecting plate 14, and a collecting member 22. A pulley 21 is provided for movement. The optical path adjusting member 12 is an assembly of optical components as described above, and includes the beam expander and homogenizer 2, the collimation lens 3, and the cylindrical lens 4 group shown in FIG.

  In FIG. 3, the belt-like laser light 5 emitted from the laser light source 11 and passed through the optical path adjusting member 12 is introduced into the housing 23 and irradiated onto the belt-like melted portion (end portion) 6 a of the polymer sheet 6. A polymer sheet feeding device 13 having a motor and a mechanism for converting the rotational motion of the motor into a linear motion is attached to the upper portion of the housing 23. The polymer sheet 6 is attached to the polymer sheet feeding device 13. And are continuously fed into the housing 23. On the other hand, the lower part of the polymer sheet 6 is held by a holding member 16 to which an electrode 17 is attached. Since the polymer sheet 6 and the electrode 17 are always in contact with each other, a charge is applied to the polymer sheet 6 when a voltage is applied to the electrode 17.

  The fiber collecting plate 14 (which functions as an electrode paired with the electrode 17) is paired with the electrode 17 at a position facing the polymer sheet 6 through the band-shaped melted portion (end portion) 6a and the collecting member 23. It is arranged. Therefore, when a voltage is applied to the electrode 17 and the fiber collecting plate 14, a potential difference is generated between the belt-shaped melted portion (end portion) 6 a of the polymer sheet 6 and the collecting member 22. The application of voltage to the electrode 17 and the fiber collecting plate 14 is performed by the high voltage generators 20a and 20b connected thereto. In this nonwoven fabric manufacturing apparatus, the electrode 17 is a positive electrode and the fiber collecting plate 14 is a negative electrode. The collecting member 22 is a belt conveyor including a pulley 21 and a conveyor belt, and the conveyor belt itself corresponds to the collecting member 22. Therefore, as the pulley 21 is driven, the collecting member 22 (conveyor belt) moves in a predetermined direction (for example, rightward in the figure).

  The nonwoven fabric manufacturing apparatus shown in FIG. 3 includes a heating device 15 and can heat the stretched fibers discharged from the belt-shaped melted portion (end portion) 6a of the polymer sheet 6 toward the collecting member 23. . In addition, the housing 23 is provided with a laser light absorption plate 19 and a heat absorption plate 18.

  In the nonwoven fabric manufacturing apparatus shown in FIG. 3, the polymer sheet 6 is fed while the polymer sheet 6 is fed by the polymer sheet feeding device 13 and the holding member 16 in a state where a voltage is applied to both the electrode 17 and the fiber collecting plate 14. By irradiating the belt-like melted portion (end portion) 6a with the belt-like laser beam 5, a tailor cone is formed on the belt-like melted portion (end portion) 6a of the polymer sheet 6 as described above. The fibers are discharged and fly to the fiber collecting plate 14, and as a result, the elongated fibers are collected by the collecting member 22. And the nonwoven fabric can be manufactured on the collection member 22 by moving the collection member 22 while feeding the polymer sheet 6 continuously (discharging fiber continuously).

  In the nonwoven fabric manufacturing apparatus shown in FIG. 3, the collection member 22 is a sheet-like member. In this apparatus, the collecting member 22 is not particularly limited as long as it is in the form of a sheet, but is paper, film, various woven fabrics, non-woven fabric, mesh or the like. Further, the collecting member may be a metal or a sheet or a belt having a surface electric resistance value equivalent to that of a metal.

  In the nonwoven fabric manufacturing apparatus shown in FIG. 3, the material of the electrode 17 and the fiber collecting plate 14 may be a conductive material (usually a metal component). For example, a group 6A element such as chromium or a group 8 metal such as platinum. Element, group 1B elements such as copper and silver, group 2B elements such as zinc, group 3B elements such as aluminum, etc. simple metals and alloys (aluminum alloys, stainless steel alloys, etc.), or compounds containing these metals (silver oxide, Metal oxides such as aluminum oxide) and the like. 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. The shape of the fiber collecting plate 14 is not particularly limited, and examples thereof include a plate shape, a roller shape, a belt shape, a net shape, a saw shape, a wave shape, a needle shape, and a line shape. Of these shapes, a plate shape and a roller shape are particularly preferable. Examples of the laser light absorbing plate 19 include a metal coated with a black body and a porous ceramic. Examples of the heat absorbing plate 18 include black ceramic. By using such an apparatus, the high melting point resin fiber and the nonwoven fabric of the present invention can be efficiently produced.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

(Production of polymer sheet)
Polymer sheets A to D were prepared by the following method.
Using a T-die with a die width of 150 mm and a lip width of 0.4 mm, a chip-like sample of PEEK resin, which is the following high-melting-point resin, is used in a lab plast mill T-die extrusion molding apparatus (manufactured by Toyo Seiki Seisakusho). Extruded into a sheet at an extrusion temperature of 345 to 360 ° C., wound up at a take-up roll temperature of 140 ° C. and a winding speed of 1.0 to 2.0 m / min, to prepare polymer sheets A to D having a thickness of 0.1 mm. . The polymer sheets B, C, and D were subjected to heat treatment at 230 ° C. for 20 minutes after molding with an extruder.
The crystallinity of the produced polymer sheet and the viscosity at a shear rate (shear rate) of 121.6 (1 / s) measured at 400 ° C. were as follows. In addition, the said viscosity was measured with the measuring method of the viscosity of the following polymer sheets, and the said crystallinity degree was calculated | required by the same method as the crystallinity degree of the following high melting point resin fibers.
Polymer sheet A: VESTAKEEEP 1000G (Non-changing sample raw fabric: crystallinity 12.7%, viscosity 151 Pa · s)
Polymer sheet B: VESTAKEEEP 1000G (crystalline sample raw material: crystallinity 35.5%, viscosity 151 Pa · s)
Polymer sheet C: VESTAKEEEP 3300G (crystalline sample raw material: crystallinity 36.7%, viscosity 761 Pa · s)
Polymer sheet D: VESTAKEEEP 4000G (crystalline sample raw material: crystallinity 37.7%, viscosity 1012 Pa · s)

(Measurement method of viscosity of polymer sheet)
The viscosity at a shear rate (shear rate) of 121.6 (1 / s) measured at 400 ° C. was measured with a capillary rheometer (trade name “Capillograph 1D”, manufactured by Toyo Seiki Seisakusho Co., Ltd.) with a capillary diameter of 1 mm. Measured using a 10 mm long jig.

  Next, in Examples 1 to 3 and Comparative Examples 1 to 5, using the polymer sheets A to D produced by the above method, high melting point resin fibers were produced by the following method. In Examples 1 to 3 and Comparative Examples 1 to 5, the polymer sheet used, the feeding speed of the polymer sheet, the output of the laser beam, the crystallinity of the obtained high melting point resin fiber, and the fiber diameter (diameter) are listed. As shown in FIG. In Comparative Examples 2 and 5, no fiber was obtained.

(Manufacture of high melting point resin fibers)
The high melting point resin fibers of Examples 1 to 3 and Comparative Examples 1 to 5 were manufactured using the apparatus shown in the schematic diagram of FIG.
As the laser light source 1 of the apparatus shown in FIG. 1, a CO ² laser (Universal Laser Systems, wavelength 10.6 μm, output 45 W, air-cooled type, beam diameter φ4 mm) was used. As the beam expander and homogenizer 2, a beam expander with a magnification of 2.5 times, a homogenizer (incident beam diameter φ12 mm (design value), output beam diameter φ12 mm (design value)), and a collimation lens 3 as a collimation lens (incident beam diameter) A cylindrical lens (plano-concave lens, f-30 mm) and a cylindrical lens (plano-convex lens, f-300 mm) as a cylindrical lens group 4 in a predetermined order in this order are φ12 mm (design value), output beam diameter φ12 mm (design value). The one arranged at the position was used. By passing through these optical path adjusting members, the spot-shaped laser beam is converted into a band-shaped laser beam having a width of about 150 mm and a thickness of about 1.4 mm and irradiated to the band-shaped melted portion (end portion) 6 a of the polymer sheet 6. . Thereby, a high melting point resin fiber was obtained.

(Measurement method of crystallinity of high melting point resin fiber)
The crystallinity of the high melting point resin fiber was calculated from the amount of heat obtained from DSC measurement.
The DSC measurement uses a differential scanning calorimeter (DSC-Q2000 / TA), alumina as a reference material, a nitrogen atmosphere, a temperature range of 0 ° C. to 420 ° C., and a heating rate of 20 ° C./min. went.
And from the calorie | heat amount calculated | required by DSC measurement, the crystallinity degree was calculated | required using the following formula | equation.
Crystallinity (%) = {(heat of fusion of sample) − (heat of recrystallization of sample)} / heat of fusion of complete crystal (130 J / g) × 100

DESCRIPTION OF SYMBOLS 1 Laser generating source 2 Beam expander and homogenizer 3 Collimation lens 4 Cylindrical lens group 5 Band-shaped laser beam 6 Polymer sheet 6a Band-shaped melting part 6b Needle-shaped protrusion part 7 Holding member 8 Fiber collection board 9 Thermography 10 High voltage generator 11 Laser generating source 12 Optical path adjusting member 13 Polymer sheet feeding device 14 Fiber collecting plate 15 Heating device 16 Holding member 17 Electrode 18 Heat absorbing plate 19 Laser light absorbing plate 20a High voltage generating device 20b High voltage generating device 21 Pulley 22 Collecting Member 23 Case

  Since the high melting point resin fiber of the present invention is very fine and excellent in heat resistance and chemical resistance, the nonwoven fabric obtained by using this is a separator for fuel cells, a filter for medical materials, a space material, etc. Useful as.

Claims (6)

A high melting point resin fiber made of PEEK having a crystallinity of 30% or less and a diameter of 4 μm or less. A polymer sheet made of PEEK having a degree of crystallinity of 25% or less is irradiated with a band-shaped laser beam to heat and melt the end of the polymer sheet in a linear shape, and between the melted band-shaped melted part and the fiber collecting plate By providing a potential difference therebetween, a needle-like protrusion is formed in the belt-like melted portion of the polymer sheet, and the fibers discharged from the needle-like protrusion are caused to fly in the direction of the fiber collecting plate, thereby collecting the fibers. plates or manufacturing of the high melting point resin fiber according to claim 1 Symbol mounting, characterized in that to obtain a high melting point resin fiber by collecting on a collecting member interposed said fiber collection plates and the molten portion Method. The method for producing a high melting point resin fiber according to claim 2 , wherein a feeding speed of the polymer sheet is 2 to 20 mm / min. The method for producing a high melting point resin fiber according to claim 2 or 3 , wherein the potential difference is 0.1 to 30 kV / cm. The high melting point according to any one of claims 2 to 4 , wherein the polymer sheet has a viscosity at a shear rate (shear rate) of 121.6 (1 / s) measured at 400 ° C of 800 Pa · s or less. Manufacturing method of resin fiber. Nonwoven fabric obtained from the high melting point resin fiber according to claim 1 Symbol placement.

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