WO2011105414A1 - Porous pfa sheet - Google Patents

Porous pfa sheet Download PDF

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Publication number
WO2011105414A1
WO2011105414A1 PCT/JP2011/053944 JP2011053944W WO2011105414A1 WO 2011105414 A1 WO2011105414 A1 WO 2011105414A1 JP 2011053944 W JP2011053944 W JP 2011053944W WO 2011105414 A1 WO2011105414 A1 WO 2011105414A1
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WO
WIPO (PCT)
Prior art keywords
filament
pfa
porous sheet
fine particles
filaments
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PCT/JP2011/053944
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French (fr)
Japanese (ja)
Inventor
鈴木　章泰
幸司 黒田
Original Assignee
国立大学法人山梨大学
グンゼ株式会社
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Application filed by 国立大学法人山梨大学, グンゼ株式会社 filed Critical 国立大学法人山梨大学
Priority to CN2011800055066A priority Critical patent/CN102753744A/en
Publication of WO2011105414A1 publication Critical patent/WO2011105414A1/en

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    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
    • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
    • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
    • D04H1/4326—Condensation or reaction polymers
    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H3/00—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
    • D04H3/005—Synthetic yarns or filaments
    • D04H3/009—Condensation or reaction polymers

Definitions

  • the present invention relates to a porous PFA characterized in that a filament group composed of PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) of 10 ⁇ m or less and each filament has a large number of PFA fine particles having a diameter of the filament or less.
  • the present invention relates to a PFA porous sheet made of microfilaments having increased strength and specific surface area as a result of containing many PFA fine particles.
  • Fluoropolymers have many excellent properties such as high heat resistance, good chemical resistance, excellent weather resistance, excellent electrical properties, non-adhesive surface and low friction coefficient. It is a useful functional polymer.
  • Polytetrafluoroethylene (PTFE) which is a typical example, has the highest heat resistance, but melt molding is difficult and is often limited in practice.
  • PFA is used as a high-performance polymer in many fields in place of PTFE because it can be melt-molded.
  • a porous sheet made of PFA is useful in various fields as a highly functional porous sheet of the polymer. In particular, it has attracted attention in the fields of medical use and precision electrical equipment due to its good chemical resistance and good electrical characteristics.
  • the porous sheet becomes thinner and the specific surface area increases. It was requested in.
  • the PFA porous sheet has high strength as a porous sheet because the friction coefficient between the filaments is small because the non-adhesiveness of the polymer and the friction coefficient are small, although the strength of the polymer constituting the PFA porous sheet is strong. There were many cases where smallness was a problem.
  • the present inventor has already realized a PFA porous sheet made of microfilament (International Publication WO2008 / 084797A1).
  • the present invention provides means for further reducing the filament diameter of the porous sheet and increasing the tensile strength of the porous sheet.
  • the present invention relates to a technique for stretching a filament by infrared heating, and there is an earlier application (International Publication No. WO2008 / 084797A1) related to stretching under reduced pressure.
  • the present invention further improves these techniques so that it can be effectively applied to a PFA porous sheet.
  • the present invention is a further development of the inventor's conventional technology.
  • the purpose of the present invention is to increase the strength of the PFA porous sheet, increase the specific surface area, and facilitate handling as a stable porous sheet. It is a thing.
  • Another object is to provide means for stably producing a PFA porous sheet with high productivity.
  • the present invention has been made to achieve the above object, and features as a PFA porous sheet are as follows.
  • the present invention relates to a PFA porous sheet, wherein the PFA porous sheet includes a filament group composed of PFA having an average filament diameter of 10 ⁇ m or less, and a large number of PFA fine particles each of which has an average filament diameter of 1 or less.
  • the present invention also relates to the PFA porous sheet, wherein the PFA filament has an average filament diameter of nm of less than 1 ⁇ m.
  • the present invention relates to the PFA porous sheet, wherein the fine particles are melted and the fine particles and the filaments and the fine particles are fused to each other. *
  • the present invention provides means for stably producing the PFA porous material, and the features as the production means are as follows.
  • a multi-filamentary PFA original filament is sent out by the feeding means under P1 atmospheric pressure, and the original filament group passes through the orifice and is led to a drawing chamber under P2 atmospheric pressure (P1> P2).
  • P1> P2 atmospheric pressure P1> P2 atmospheric pressure
  • the original filament group that has passed through the orifice is heated by being irradiated with the carbon dioxide laser beam, and drawn by the traction force generated by the gas flow from the orifice caused by the pressure difference between P1 and P2.
  • the present invention relates to a method for producing a PFA porous sheet.
  • the present invention also relates to the method for producing a PFA porous sheet, wherein P1 is atmospheric pressure and P2 is under reduced pressure.
  • the present invention is characterized in that the original PFA filament group of multi-pillars exiting the orifice is started to be stretched after searching for a portion where the laser beam uniformly hits by rotating the entire stretching chamber,
  • the present invention relates to a method for producing a PFA porous sheet.
  • the present invention also relates to the method for producing a PFA porous sheet, wherein the original filament is irradiated within 30 mm from the outlet of the orifice at the center of the carbon dioxide laser beam.
  • the present invention also relates to the method for producing a PFA porous sheet, wherein the carbon dioxide laser beam is irradiated to a range within 4 mm in the vertical direction along the axial direction of the filament at the center of the original filament.
  • the present invention also relates to the method for producing a PFA porous sheet, wherein the stretched filament group and a large number of fine particles are collected by a conveyor running in the stretch chamber.
  • the stretched filament group and the accumulation of a large number of fine particles are wound around the rotating shaft of the winder in the stretching chamber, and the stretched filament group descends outside the rotating shaft.
  • the PFA has a width corresponding to the width of the incoming wire, and assists in effectively winding a group of filaments around the rotating shaft by a collection guide having a wall curved along the rotating shaft.
  • the present invention relates to a method for producing a porous sheet. Furthermore, the present invention is characterized in that when the porous sheet containing the fine particles is heat-treated at 270 ° C. or higher, the fine particles are melted and the fine particles, the filaments, and the fine particles are fused. And a method for producing the PFA porous sheet.
  • the present invention relates to a porous sheet made of a PFA filament.
  • PFA is a type of fluoropolymer that has heat resistance close to that of polytetrafluoroethylene, good chemical resistance, excellent weather resistance, excellent electrical properties, and non-adhesive surface. Since it has many excellent properties such as a low friction coefficient, it is used in many fields where such functions are desired. In particular, it has excellent tensile strength at 150 ° C. to 260 ° C., and is used as a high-performance polymer in many fields in place of PTFE, which is difficult to be melt-molded such as melt spinning. In addition, the case where the PFA polymer of the present invention contains 85% (weight percent) or more of PFA is included. These contents are determined by an infrared analyzer or the like.
  • the PFA porous sheet of the present invention is characterized in that the constituent filament group is a microfilament of 10 ⁇ m or less.
  • the filament is a kind of fiber having a substantially continuous length, but is usually smaller than about 50 mm and longer than what is called a short fiber, and is 100 mm or more. Since it is small, its aspect ratio (length / diameter) is very large.
  • the filaments of the present invention are characterized by comprising filaments having an average filament diameter of 10 ⁇ m or less, desirably 3 ⁇ m or less, and most preferably comprising nanofilaments that do not reach 1 ⁇ m.
  • the filament diameter (average filament diameter) is obtained by arithmetically averaging 100 filaments under an electron microscope of several thousand to 10,000 times.
  • the porous sheet of the present invention is also characterized in that the filament diameter is very uniform compared to the nonwoven fabric obtained from the ES method and the melt blown nonwoven fabric, which is a porous sheet composed of other fine fibers. .
  • a non-woven fabric is a porous sheet that is usually formed into a sheet by entanglement between some fibers.
  • the filament diameter is very small, the number of PFA filaments per unit weight is extremely large. Therefore, even if the interlacing step is not particularly provided, the filaments are entangled when the PFA filaments are accumulated like the melt blown nonwoven fabric, and can be used after being formed into a sheet with a simple press.
  • means such as hot embossing, needle punching, water jet, adhesive bonding, etc., which are performed with ordinary nonwoven fabrics, can also be used and are selected depending on the application.
  • filter applications which is a major application of ultrafine fiber nonwoven fabrics, the collection efficiency can be increased by orders of magnitude by electret processing of the nonwoven fabric, and the nonwoven fabric of the present invention can also be electret processed and applied to the filter field .
  • a porous sheet made of PFA is useful in various fields as a highly functional porous sheet of the polymer.
  • it has attracted attention in the fields of medical use and precision electrical equipment due to its good chemical resistance and good electrical characteristics.
  • the porous sheet becomes thinner and the specific surface area increases. It was requested in.
  • the PFA porous sheet has high strength as a porous sheet because the non-adhesiveness of the polymer and the coefficient of friction are small, but the coefficient of friction between the filaments is small because the strength of the polymer constituting the PFA porous sheet is high. There was a case where smallness was a problem.
  • the porous sheet of the present invention includes a large number of PFA fine particles having a diameter equal to or less than the filament diameter, in addition to the individual filaments constituting the porous sheet.
  • a direct-spun type nonwoven fabric such as a normal spunbond nonwoven fabric or a melt blown nonwoven fabric, crushing or particles called dama or shot are present.
  • these so-called lumps and the like are several times larger than the filament diameter, usually 10 times larger, and are treated as defects of the nonwoven fabric.
  • the fine particles of the present invention have a diameter smaller than the filament diameter, and provide various advantages in the porous sheet as described later.
  • the fine particles in the present invention are usually spherical, and the diameter (average diameter) is not more than the filament diameter (average filament diameter) constituting the porous sheet. Since the average filament diameter in the present invention is 10 ⁇ m or less, the average particle diameter is also 10 ⁇ m or less, and it is usually less than 1 ⁇ m and consists of nanoparticles having a diameter of several tens to several hundreds of nm. As described above, the fine particles of the present invention have a small particle size, which contributes to a very large specific surface area of the porous sheet of the present invention.
  • the particle diameter (average particle diameter) is obtained by arithmetic average by measuring the diameter of 100 particles with a dimensional gauge shown under the microscope under an electron microscope of several thousand to 10,000 times.
  • multiple means that a plurality of fine particles are confirmed with respect to one filament under a 10,000 ⁇ electron microscope field of view. It is because the effect of increasing the strength of the porous sheet or increasing the specific surface area, which is the object of the present invention, cannot be expected due to the fusion of the gaps. Is another feature, which is also different from “dama” or shots of spunbond nonwoven fabrics and meltblown nonwoven fabrics.
  • the PFA fine particles in the present invention are melted by heat treatment, and the fine particles and the filaments and the fine particles are fused together to be integrated as a porous sheet.
  • a porous sheet made of PFA filaments which are non-adhesive and have a small coefficient of friction is also fused and integrated in this way, thereby increasing the tensile strength of the sheet and providing a sheet with dimensional stability.
  • the PFA porous sheet of the present invention is an application of the ultra-high magnification drawing means for filaments utilizing the pressure difference between the carbon dioxide laser beam and the orifice of Patent Document 1, which is the invention of the present inventor, to the PFA filament.
  • PFA raw filaments are super-stretched from several tens of micrometers to several hundreds of micrometers in diameter and from several tens of thousands to several hundreds of thousands of times to become ultrafine filaments ranging from several micrometers to several tens of nanometers.
  • the PFA original filament in the present invention is already manufactured as a filament and wound on a reel or the like.
  • a melted or melted filament that has become a filament by cooling or coagulation is used subsequently in the spinning process, and can be used as the original filament of the present invention.
  • the filament is a substantially continuous fiber, and is distinguished from a short fiber having a length of several mm to several tens of mm.
  • the original filament is desirably present alone, but it can be used even if it is assembled into several to several tens.
  • the original filament sent out from the filament sending means is stretched.
  • various types can be used as long as the filament can be delivered at a constant delivery speed, such as a combination of a nip roller and several stages of driving rollers.
  • the multifilamentary PFA original filament is sent out by the feeding means under P1 atmospheric pressure, passes through the orifice, and is led to the drawing chamber under P2 atmospheric pressure (P1> P2).
  • the original filament group that has passed through the orifice is heated by being irradiated with a carbon dioxide laser beam, and is stretched by a traction force generated by a gas flow generated by a pressure difference between P1 and P2.
  • the apparatus can be simplified that the pressure P1 when the original filament group is sent out is atmospheric pressure and the pressure P2 in the drawing chamber is under reduced pressure.
  • the stretching chamber may be divided into a narrowly defined stretching chamber in which the original PFA filaments are stretched by a laser beam at the exit of the orifice, and a narrowly defined filament collecting chamber in which the stretched filaments are collected. And the filament collecting chamber in a narrow sense are integrally coupled and kept at the same atmospheric pressure to form a stretching chamber in a broad sense.
  • the original filament supply chamber and the drawing chamber are connected by an orifice.
  • a high-speed gas flow generated by a pressure difference of P1> P2 is generated in a narrow gap between the original filament and the orifice inner diameter.
  • the inner diameter D of the orifice and the diameter d of the fiber should not be too large.
  • the above-mentioned orifice inner diameter D is the diameter at the outlet of the orifice.
  • the orifice cross section is not a circle, the diameter of the narrowest part is D.
  • the smallest diameter value is d, and 10 points are measured and averaged based on the smallest cross section.
  • the inner diameter of the orifice is not a uniform diameter but is preferably tapered and narrowed at the outlet.
  • the lower part of the vertically arranged orifice is the outlet, but when the original filament passes from the bottom to the top, it is above the orifice. There is an exit.
  • the orifice is placed laterally and the original filament passes laterally, there is an outlet transverse to the orifice.
  • the orifice has a low resistance structure.
  • the orifices according to the present invention may be used independently of each other, but a large number of orifices may be formed by opening a large number of holes in a plate-like object.
  • a circular cross section inside the orifice is desirable, but when a plurality of filaments are allowed to pass, or when the filament has an oval or tape shape, an oval or rectangular cross section is also used.
  • the orifice entrance is large so that the original filament can be easily introduced and only the exit portion is narrow because the running resistance of the filament can be reduced and the wind speed from the exit of the orifice can be increased.
  • the orifice in the present invention has a role different from that of the conventional blower pipe before stretching by the present inventors.
  • the conventional blower tube has a role of applying a laser to a fixed position of the filament, and has a function of conveying the original filament to the fixed position with as little resistance as possible.
  • the present invention is different from that in that a high-speed gas flow is generated due to a difference in pressure between the pressure P1 in the original filament supply chamber and the pressure P2 in the drawing chamber.
  • tension is applied to the molten filament by air soccer or the like.
  • the air soccer in the production of the spunbonded nonwoven fabric and the orifice in the present invention are completely different in operation mechanism and effect.
  • the molten filament is fed by a high-speed fluid in the air soccer, and most of the filament diameter is reduced in the air soccer.
  • the solid original filament is sent by the orifice, and the filament does not start to be thinned in the orifice, but is first drawn by being irradiated with the laser beam at the exit from the orifice.
  • high-speed fluid is generated by sending high-pressure air into the air soccer.
  • the present invention is different in that high-speed fluid is generated in the orifice due to the pressure difference between the rooms before and after the orifice.
  • the spunbond method is different in that only a filament diameter of about 10 ⁇ m can be obtained at most, whereas the present invention provides a great effect that nanofilaments of less than 1 ⁇ m can be obtained.
  • the flow velocity in the orifice is preferably 50 m / sec or more, more preferably 100 m / sec or more, and most preferably 200 m / sec or more. These flow rates are determined by the raw material filament material, the target filament diameter, and the like.
  • the original filament sent out from the orifice is heated by the carbon dioxide laser beam at the outlet of the orifice, and the original filament is drawn by the tension applied to the filament by the high-speed fluid from the orifice.
  • “Directly under the orifice” means that, as a result of experiments, the center of the carbon dioxide laser beam is 30 mm or less, preferably 10 mm or less, preferably 5 mm or less from the tip of the orifice. This is because when the filament is separated from the orifice, the original filament swings and does not stay in a fixed position and cannot be stably captured by the carbon dioxide laser beam. Further, it is considered that the tension applied to the filament by the high-speed gas from the orifice is weakened by moving away from the orifice, and the stability is also reduced.
  • the present invention is characterized in that the original filament is heated and drawn by a carbon dioxide laser beam.
  • the carbon dioxide laser beam of the present invention has a wavelength of around 10.6 ⁇ m.
  • the laser can narrow down the irradiation range (beam) and is concentrated on a specific wavelength, so that there is little wasted energy.
  • the carbon dioxide laser of the present invention has a power density of 50 W / cm 2 or more, preferably 100 W / cm 2 or more, and most preferably 180 W / cm 2 or more. This is because the ultrahigh magnification stretching of the present invention can be achieved by concentrating energy of high power density in a narrow stretching region.
  • the original filament of the present invention is heated to a suitable temperature for stretching by a carbon dioxide laser beam, but the range heated to the suitable temperature for stretching is within 4 mm (length: 8 mm) in the vertical direction along the axial direction of the filament at the center of the filament. More preferably, the heating is performed at a top and bottom of 3 mm or less, most preferably at a top and bottom of 2 mm or less.
  • the beam diameter is measured along the axial direction of the traveling filament. In the present invention, since there are a plurality of original filaments, the measurement is performed in the axial direction of the original filaments.
  • the present invention makes it possible to stretch highly narrowed to a nano region by being rapidly stretched in a narrow region, and to reduce stretch breaks even with ultra-high magnification stretching. It was.
  • the center of the filament means the center of a multifilament filament bundle. *
  • the multi-element original PFA filament group exiting the orifice is stretched by being irradiated with a laser beam. At that time, it is necessary to uniformly irradiate the multi-filamentary original filament group with the laser beam.
  • a suitable position where all the original filament groups are uniformly stretched is searched while the entire stretching chamber is rotated finely. It is preferred to begin stretching at its preferred rotational position. It should be noted that the entire stretching chamber is not only rotated, but is also finely moved in the lateral direction (X direction), the beam irradiation direction (Y direction), and the height direction (Z direction) to find a suitable position. .
  • a traveling conveyor is used as the stretched filament accumulation device of the present invention. By collecting and laminating on a conveyor, it can be wound up as an aggregate of fine filaments or a porous sheet. By doing in this way, the porous sheet which consists of nanofilaments can be manufactured.
  • a net-like moving body is usually used, but it may be accumulated on a belt or a cylinder.
  • the multi-filamentary ultrafine filaments stretched according to the present invention are accumulated on the traveling cloth-like material, so that a laminated body laminated with the cloth-like material can be manufactured.
  • an aggregate or a porous sheet made of nanofilaments is difficult to handle because the filaments constituting it are very thin, but the handling is stabilized by being laminated with a cloth-like material in this way.
  • it can also be used as it is for uses, such as a filter, by laminating
  • the cloth-like material woven fabric, knitted fabric, non-woven fabric, felt, paper or the like is used.
  • the film may be run and accumulated on it.
  • a winding device such as a filament group or a sheet is also used.
  • a take-up machine in which a tubular body of paper or aluminum tube corresponding to the width of the filament group that has been stretched and descended is attached as a rotating shaft. The filaments stretched on these tubular bodies are collected and collected. It is collected and rolled up.
  • This collection guide has a width corresponding to the width by which the multifilamentary extended filament group descends outside the rotating shaft.
  • the corresponding width is most preferably wider than the width when the filament group descends, preferably around 50 mm, more preferably around 100 mm on both sides.
  • the high-speed air is bent in the direction of the rotation axis of the winder by the wall of the collection guide, and the stretched filaments can be prevented from scattering.
  • the distance from the winding shaft to the wall of the collection guide is most preferably 500 mm or less, preferably 200 mm or less, and 100 mm or less.
  • the stretched filament group accumulated on the conveyor is preferably heat treated to form a sheet.
  • the porous sheet is preferably wound around a sheet winding device provided in the stretching chamber.
  • the heat treatment is performed by allowing the porous sheet to pass through a space in which hot air is circulated, or by passing it over a roll that is heated by induction heating or the like.
  • the heat treatment temperature of the PFA porous sheet of the present invention is at least 270 ° C. or more, the fine particles are melted, the fine particles, the filaments, and the fine particles are fused together, and the tensile strength is high and the dimensional stability is high. It becomes a PFA porous sheet.
  • the drawn filaments are all expressed as filaments, but include those belonging to the fiber region as a result of drawing.
  • the stretched filament in the present invention is stretched for several minutes without being stretched. Therefore, considering the fact that the length of the filament is several meters or more and the filament diameter d is small, it is substantially continuous. In most cases, it can be regarded as a filament. However, depending on conditions, short fibers belonging to the above-mentioned fiber region can also be produced.
  • the porous sheet in the present invention is manufactured by accumulating stretched PFA ultrafine filaments on a conveyor or a winding shaft.
  • a porous sheet made of ultrafine filaments may be expressed as a nonwoven fabric, in the present invention, it is expressed as a porous sheet because it has fine particles and has a side surface different from that of the nonwoven fabric.
  • non-woven fabrics are not only a substitute for woven fabrics, but also the unique properties of non-woven fabrics have attracted attention, and the demand for various non-woven fabrics has increased.
  • melt-blown nonwoven fabric as a porous sheet of ultrafine fibers.
  • a filament of around 3 ⁇ m is obtained by blowing molten filaments with hot air, and it is accumulated on a conveyor to form a porous sheet, mainly an air filter. in use.
  • the filament constituting the meltblown nonwoven fabric has a strength of around 0.1 cN / dtex, which is weaker than that of a normal unstretched fiber, and also has a defect that there are many small lumps of resin called shots or lumps.
  • the porous sheet composed of the stretched PFA filament of the present invention has a filament diameter of about 3 ⁇ m, which is the same as that of the meltblown nonwoven fabric, and a filament diameter up to a nanofilament region smaller than that, but the PFA filament is highly Since it is molecularly oriented, it has a strength close to that of a normal stretched synthetic fiber. Moreover, a porous sheet containing no shots or lumps can be obtained.
  • the porous sheet of the present invention has an effect of improving performance such as dense fabric and gloss, light weight, heat insulation, water repellency and the like due to being an ultrafine filament.
  • the porous sheet made of the PFA filament of the present invention is characterized by a large specific surface area because the filament diameter is thin and uniform. As described in the background art section, various spunbond nonwoven fabrics made of PFA filaments have been studied in the past, but the filaments of the present invention are stronger than those spunbond nonwoven fabrics and have a filament diameter. small.
  • An object of the present invention is to produce an ultrafine filament by stretching an original filament at an ultrahigh magnification with a carbon dioxide laser beam.
  • the ultrafine filament in the present invention refers to a filament that is made ultrafine by stretching the original filament 100 times or more.
  • the ultrafine filaments those having a filament diameter of less than 1 ⁇ m are particularly called nanofilaments.
  • the present invention is characterized in that nanofilaments can be obtained even from original filaments having a diameter of 100 ⁇ m or more by making the original filament have a draw ratio of 10,000 times or more.
  • the draw ratio ⁇ in the present invention is represented by the following formula from the diameter do of the original filament and the diameter d of the filament after drawing. In this case, the density of the filament is calculated as constant.
  • the fiber diameter is measured with a scanning electron microscope (SEM) using an average value of 100 points based on a photograph taken at a magnification of 350 times for the original filament and 1000 times or more for the drawn filament.
  • SEM scanning electron microscope
  • the drawn filaments according to the present invention are characterized by uniform filament diameters.
  • the filament diameter distribution was obtained by measuring 100 filament diameters from the above SEM photograph using length measurement software. Moreover, the standard deviation was calculated
  • the drawn filament in the present invention is molecularly oriented by being drawn and is thermally stable. Since the drawn filament of the present invention has a very small filament diameter, it is difficult to measure the molecular orientation of the filament. The results of thermal analysis suggest that the drawn filament of the present invention is not only thinned but also has molecular orientation.
  • the differential thermal analysis (DSC) measurement of the original filament and the drawn filament was carried out at a heating rate of 10 ° C./min using a THEM PLUS2 DSC8230C manufactured by Rigaku Corporation.
  • the present invention is characterized in that a PFA porous sheet made of microfilaments is accompanied by PFA fine particles. Since the fine particles are smaller than the filament diameter, the specific surface area of the porous sheet is increased. The specific surface area is a surface area per unit weight. The fine particles of the present invention are smaller than the filament diameter, and usually have a specific surface area of 1/10 to 1/5 of the filament diameter.
  • the PFA fine particles of the present invention When the PFA fine particles of the present invention are melted, they function as an adhesive effect that joins the fine particles and the filaments or between the fine particles, and contributes to an increase in the mechanical strength of the porous sheet.
  • an adhesive is used for the purpose of strengthening the inter-filament bonding of the nonwoven fabric.
  • the method of applying the adhesive later increases the cost, and the emulsion or the solvent-based adhesive has a drawback that a film is stretched over the entire porous sheet and air permeability is impaired.
  • the fine-powder adhesive does not exist in the fluorine-based adhesive, and even if it exists, the cost is high, and it is difficult to uniformly adhere this powder adhesive to the porous sheet.
  • the porous sheet obtained by melting the fine particles is uniform and fine. It becomes a microporous sheet having many holes.
  • the porous sheet obtained by the present invention is used as a highly functional porous sheet such as a filter, various separators, and water-impervious clothing.
  • the ES method which is a conventional nanofiber production method, requires the solvent to be removed from the work of dissolving the polymer in the solvent or the finished product, which is complicated in the manufacturing method and increases the cost.
  • the finished product also had problems with the quality of the filament, such as the occurrence of a mass of resin called lumps and shots, and a wide distribution of filament diameters.
  • the resulting fiber is also a short fiber (short fiber), which is said to be several millimeters in length to several tens of millimeters at most.
  • the PFA porous sheet of the present invention is a very useful functional sheet.
  • the present invention can obtain a PFA ultrafine filament with improved molecular orientation easily by a simple means without requiring a special, high precision and high level apparatus.
  • the present invention is also characterized in that a stretched filament can be directly wound on a winder to form a porous sheet.
  • the PFA filament can be drawn at a magnification of 10,000 times or more, and an ultrafine filament reaching a nanofilament region of less than 1 ⁇ m can be produced.
  • the distribution of the filament diameter was the average filament diameter in the nanofilament region, it was possible to obtain a very narrow filament with a standard deviation of 0.5 or less.
  • a pressure difference before and after the orifice is used as means for generating a high-speed gas flow to which stretching tension is applied. For this reason, the flow of the high-speed gas flow is very stable, which not only provides nanofilaments but also enables stable continuous operation in terms of productivity.
  • the present invention is characterized in that a plurality of original filaments can be drawn from one carbon dioxide laser beam. Furthermore, since the present invention can be performed in a closed closed chamber, compared to the melt blow method and ES method performed in an open system, the obtained nanofibers can be prevented from scattering into the atmosphere, and the working environment is safe. High nature.
  • fine-particles of this invention The electron micrograph of the state which the PFA microparticles
  • fine-particles of this invention change by 270 degreeC heat processing compared with an unprocessed magnification
  • FIG. 8 is an electron micrograph (magnification 10,000) of a PFA porous sheet obtained by stretching a plurality of original PFA filaments with the apparatus of FIG. 8 and a fiber diameter distribution in that case.
  • Sectional drawing of the apparatus which shows an example in case the original filament supply chamber in this invention is a room
  • the conceptual diagram which shows the example which integrates
  • FIG. 1 shows an electron micrograph (magnification 10,000) of a porous sheet composed of PFA filaments with a large number of PFA fine particles of the present invention.
  • the numerous filaments in the figure show the stretched PFA porous sheet accumulated on a conveyor net running at 0.030 m / min. All filaments are 10 ⁇ m or less from 200 nm to 800 nm from the dimensional display in the figure. In addition, a large number of fine particles adhere to each filament in the figure and are observed.
  • the particles are spherical and have a diameter of 100 nm or less, all of which are smaller than the observed filament diameter.
  • the porous sheet of this figure had a PFA raw filament of 100 ⁇ m and was stretched by 15 spindles with the stretching apparatus of FIG.
  • the orifice diameter at that time is 0.5 mm.
  • the laser oscillation device at this time was a carbon dioxide laser oscillation device manufactured by Onitsuka Glass Co., Ltd., and was used at an output of 40 W.
  • the laser beam diameter at that time is 2.4 mm.
  • the original filament was sent out at a delivery speed of 0.1 m / min.
  • the degree of vacuum in the stretching chamber is 54 kPa, and the air flow rate is 100 m / sec.
  • FIG. 2 shows an electron micrograph (magnification 10,000 times) when the PFA porous sheet of FIG. 1 is heat-treated at 300 ° C. for 1 minute. It can be seen that the filaments, the filaments and the fine particles, and the fine particles are fused together by the heat treatment.
  • FIG. 3-5 is an electron micrograph (magnification, 1,000 times, 5 times) of a PFA porous sheet manufactured under the conditions shown below when heat treated at various temperatures in a hot air space as compared to untreated. , 10,000 times, 10,000 times).
  • the untreated PFA porous sheet in this case is a sheet obtained by using an original PFA filament with a diameter of 100 ⁇ m, stretching with an orifice diameter of 0.5 mm and a laser output of 30 W, and accumulating for 10 minutes.
  • the degree of vacuum in the stretching chamber was 0.054 MPa (wind speed 300 m / sec).
  • FIG. 3 shows the case where heat treatment is performed at 260 ° C. for different times while the electron microscope magnification is changed. In FIG. 3, the melting of the fine particles is not clear.
  • FIG. 4 shows the case of 270 ° C., where the melting of the fine particles starts in 30 minutes and the fine particles are fused in 60 minutes.
  • FIG. 5 shows the case of 280 ° C., melting of the fine particles started in 30 minutes or less, and the fine particles are fused, and in 60 minutes, the fusion between the filaments is started.
  • FIG. 6 shows the appearance of the sheet and the electron micrograph of the sheet when the heat treatment time was changed when the untreated PFA porous sheet used in FIG. 3-5 was heat-treated at 300 ° C. in a hot air space. (Magnification, 10,000 times). In 1 minute or less, fusion between fine particles starts, and in 2 minutes, fusion between filaments begins.
  • FIG. 7 is a conceptual view showing the principle of manufacturing a PFA ultrafine filament by multi-spindle drawing of the present invention, and is a perspective view of the apparatus.
  • the PFA original filaments 1a, 1b, 1c,... are fed out from the state wound around the reel 2, and are fed at a constant speed by a feeding nip roller (omitted in the drawing) through a comb or the like (omitted in the drawing).
  • a large number of orifices 4 a, 4 b, 4 c,... are carved in the plate 3, and the PFA raw filament 1 sent out is guided to the orifice 4.
  • the steps up to this point in this figure are shown in the case where the pressure P1 of the original filament supply chamber is maintained at atmospheric pressure and no special room is required.
  • the extension chamber 11 is under P2 atmospheric pressure (negative pressure in this figure).
  • a laser beam 6 emitted from the carbon dioxide laser oscillation device 5 is irradiated on the original filaments 1a, 1b, 1c,... Of a multi-piece (multi) just below the orifices 4a, 4b, 4c,. .
  • the degree of vacuum is adjusted by the valve 15 to be adjusted, the number of rotations of the vacuum pump, a bypass valve, and the like.
  • the web accumulated on the conveyor 14 is accompanied by a large number of fine particles, and becomes the porous sheet 16 of the present invention.
  • a heat-treated porous sheet is obtained by heat-treating the porous sheet 16 in hot air.
  • the stretching chamber 11 and the filament accumulation chamber 13 integrated with the stretching chamber 11 are provided on the position fine adjustment bases 17, 18, 19, and the orifices 4 a, 4 b, 4c,... Are finely adjusted so that the PFA original filaments a, 1b, 1c,.
  • the bottom position fine adjustment base 18 is adjusted in the vertical (Z axis) direction
  • the middle position fine adjustment base 19 is adjusted in the lateral (X axis or Y axis) direction
  • the top position fine adjustment base 20 is It is a turntable that is rotated to fine-tune the position.
  • FIG. 8 is a conceptual diagram showing the relative relationship between the laser beam of the present invention and the orifice of a multi-cage.
  • the filament accumulation chamber 13a (the drawing chamber 11 is integrated with the filament accumulation chamber 13) mounted on the fine adjustment frame 19 made of a turntable is rotated by an angle ⁇ to finely adjust the position.
  • the position where the PFA original filament (not shown in the figure) running through the orifices 4a, 4b, 4c,... Fits within the irradiation range of the laser beam 6 is searched for, and the filament accumulation chamber 13b is set to the optimum position. In this way, by adjusting the angle ⁇ finely, the optimum position for stretching the multifilamentary original filament is obtained.
  • FIG. 9 shows an electron micrograph (magnification 10,000 times) of the left, center, and right portions of the obtained sheet when an experiment was performed with 17 spindles of an original PFA filament having a filament diameter of 100 ⁇ m using the apparatus of FIG. ) And the distribution of filament diameters of the obtained filaments.
  • the raw filament supply speed was 0.5 m / min and the orifice diameter was 0.5 mm (air flow rate 280 m / sec).
  • the obtained filaments are nanofilaments having an average filament diameter of about 500-600 nm, a standard deviation of 0.23-0.46, and it can be seen that the filament diameters are well aligned.
  • FIG. 10 is a cross-sectional view of an apparatus showing an example in which the original filament supply chamber 21 is a room having an atmospheric pressure P1 and the stretching chamber 22 is a room having a P2 atmospheric pressure.
  • the P1 atmospheric pressure in the original filament supply chamber 21 is communicated with a compressor (or a vacuum pump) through a valve 23 and a pipe 24.
  • the P1 atmospheric pressure is managed by the barometer 25.
  • the P2 atmospheric pressure in the stretching chamber 22 communicates with a vacuum pump (or a compressor) through a valve 26 and a pipe 27.
  • the P2 atmospheric pressure is managed by the barometer 28.
  • the PFA original filaments 1a, 1b and 1c are fed out from the state wound around the reels 29a, 29b and 29c, and are fed at constant speed from the feeding nip rollers 31a, 32a, 31b, 32b, 31c and 32c via the combs 30a, 30b and 30c. And are led to the orifices 33a, 33b, 33c,.
  • the PFA original filaments 1a, 1b, and 1c that have exited the orifices 33a, 33b, and 33c are guided to the drawing chamber 22 together with high-speed air caused by the pressure difference P1-P2 between the original filament supply chamber 21 and the drawing chamber 22.
  • the fed PFA original filaments 1a, 1b, and 1c are irradiated directly on the traveling original filaments 1a, 1b, and 1c with the laser beam 6 irradiated from the carbon dioxide laser oscillation device 5 immediately below the orifice.
  • a laser beam power meter 34 is preferably provided at the destination of the laser beam 6, and the laser power is preferably adjusted to be constant.
  • the original filaments 1a, 1b, and 1c are drawn by the tension applied to the lower filament by the high-speed air that is heated by the laser beam 6 and brought about by the pressure difference of P1-P2, and becomes the drawn filaments 35a, 35b, and 35c. And is accumulated on the conveyor 14 to become a PFA porous sheet 36 containing a large number of PFA fine particles.
  • the PFA porous sheet 36 on the conveyor 14 is stabilized by being sucked by the negative pressure suction chamber 37 from the back of the conveyor 14.
  • the PFA porous sheet 36 is preferably heat treated by at least one of the following heat treatment means.
  • One of the heat treatment means is radiant heat from the infrared lamp 38, and the PFA porous sheet 36 is heated and heat-treated.
  • the PFA porous sheet 36 is heated by the hot air blown from the hot air nozzle 39 to be heat-treated.
  • the porous sheet 36 exiting the conveyor 14 is preferably compressed by the rubber roll 40 on the conveyor 14 and formed into a sheet.
  • the PFA porous sheet 36 exiting the conveyor 14 is heat treated by a heating roll 41, compressed by a rubber roll 42, and formed into a sheet.
  • the heat-treated PFA porous sheet 43 is wound around a winding roll 44.
  • FIG. 11 shows an example in which a collection guide is provided in the drawing chamber when a winder is used as the filament accumulating device of the present invention.
  • a large number of holes are made in the plate-like object 51, and these holes are respectively orifices 52 a, 52 b, 52 c, and a large number of PFA original filaments 1 a, 1 b, 1 c,.
  • the orifice 52 is led to the stretching chamber 53 under P2 atmospheric pressure (in this figure, a negative pressure state).
  • the laser beam 6 emitted from the carbon dioxide laser oscillation device 5 is irradiated on the original filaments 1a, 1b, 1c,.
  • the winding device 54 includes a winding tube 56 installed on a winding stand 55, and the winding tube is driven by a motor (not shown) to rotate, and the filament stretched on the winding tube 56.
  • the extending chamber 53 is provided with a collection guide 58 that is curved along the winding tube 113.
  • the PFA porous sheet 57 is stably wound around the take-up tube 56 and becomes a PFA porous sheet 57 with good formation.
  • the present invention relates to a PFA porous sheet composed of PFA filaments with fine particles, and is used for filters, separators, water-impervious clothing, and the like.
  • 21 Raw filament supply chamber
  • 22 Stretch chamber, 23 valve, 24: Piping, 25: Barometer, 26: Valve, 27: Piping, 28: Barometer 29: Reel, 30: Comb, 31, 32: Feeding nip roll, 33: Orifice, 34: Power meter, 35: Stretched filament, 36: PFA porous sheet, 37: negative pressure suction chamber, 38: infrared lamp, 39: Hot air nozzle, 40: Rubber roll, 41: Heating roll, 42: Rubber roll, 43: Heat treated web, 44: Winding roll. 51: plate-like material, 52: orifice, 53: stretching chamber, 54: winding device, 55: Winding stand 56: Winding tube 57: PFA porous sheet 58: Collection guide.

Abstract

Disclosed is a porous PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) sheet comprising PFA filaments and having increased tensile strength and an increased specific surface area. The porous PFA sheet comprises PFA microfilaments having an average filament diameter of 10 μm or less, and is characterized in that each of the filaments contains many PFA microparticles having sizes equal to or smaller than the average filament diameter. Also disclosed is a means for producing the porous PFA sheet.

Description

ＰＦＡ多孔質シートPFA porous sheet
本発明は、１０μｍ以下のＰＦＡ（テトラフルオロエチレン・パーフルオロアルキルビニルエーテル共重合体）からなるフィラメント群と、個々のフィラメントが、このフィラメント径以下のＰＦＡ微粒子を多数有することを特徴とするＰＦＡ多孔質シートに関し、ＰＦＡ微粒子を多数含むことにより、シートとしての強度や比表面積が増大した、マイクロフィラメントからなるＰＦＡ多孔質シートに関する。 The present invention relates to a porous PFA characterized in that a filament group composed of PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) of 10 μm or less and each filament has a large number of PFA fine particles having a diameter of the filament or less. Regarding the sheet, the present invention relates to a PFA porous sheet made of microfilaments having increased strength and specific surface area as a result of containing many PFA fine particles.
　フッ素系ポリマーは、耐熱性が高く、耐薬品性が良く、優れた耐候性を示し、電気的諸特性にも優れ、表面が非粘着性で摩擦係数が小さいことなど、優れた特性を多く持ち有用な機能性ポリマーである。その代表格である、ポリテトラフルオロエチレン（ＰＴＦＥ）の耐熱性は一番高いが、溶融成形が困難であり、実用的に制限される場合が多い。ＰＦＡは溶融成形が可能であることより、ＰＴＦＥに代わって多くの分野で高機能のポリマーとして使用されている。ＰＦＡからなる多孔質シートは、そのポリマーが有する高機能を有する多孔質シートとして各方面で有用されている。特に、その耐薬品性が良いことや、電気的特性が良いことより、医療用分野や精密電気機器の分野で注目されている。それらの多孔質シートで、構成するＰＦＡフィラメントの繊維径を小さくし、１０μ以下のマイクロフィラメントにすることによって、多孔質シートが薄くなり、比表面積が増すので、より有用な素材として、それらの分野で要望されていた。しかし、ＰＦＡ多孔質シートは、その構成するポリマーの強度が強いにもかかわらず、ポリマーの非粘着性、摩擦係数が小さいことより、フィラメント間の摩擦係数が小さいために多孔質シートとしての強度が小さいことが問題となるケースが多かった。 Fluoropolymers have many excellent properties such as high heat resistance, good chemical resistance, excellent weather resistance, excellent electrical properties, non-adhesive surface and low friction coefficient. It is a useful functional polymer. Polytetrafluoroethylene (PTFE), which is a typical example, has the highest heat resistance, but melt molding is difficult and is often limited in practice. PFA is used as a high-performance polymer in many fields in place of PTFE because it can be melt-molded. A porous sheet made of PFA is useful in various fields as a highly functional porous sheet of the polymer. In particular, it has attracted attention in the fields of medical use and precision electrical equipment due to its good chemical resistance and good electrical characteristics. By reducing the fiber diameter of the PFA filaments made of these porous sheets and making them microfilaments of 10 μm or less, the porous sheet becomes thinner and the specific surface area increases. It was requested in. However, the PFA porous sheet has high strength as a porous sheet because the friction coefficient between the filaments is small because the non-adhesiveness of the polymer and the friction coefficient are small, although the strength of the polymer constituting the PFA porous sheet is strong. There were many cases where smallness was a problem.
本発明者は、マイクロフィラメントからなるＰＦＡ多孔質シートを既に実現している（国際公開公報ＷＯ２００８／０８４７９７Ａ１）。本発明は、この多孔質シートのフィラメント径を更に細くし、しかも、多孔質シートの引張強度アップする手段を提供する。 The present inventor has already realized a PFA porous sheet made of microfilament (International Publication WO2008 / 084797A1). The present invention provides means for further reducing the filament diameter of the porous sheet and increasing the tensile strength of the porous sheet.
一方、本発明は赤外線加熱によるフィラメントの延伸技術に関するものであり、しかも減圧下での延伸に関する発明者の先出願（国際公開公報ＷＯ２００８／０８４７９７Ａ１）がある。本発明は、これらの技術をさらに改良し、ＰＦＡ多孔シートに有効に適応できるようにしたものである。 On the other hand, the present invention relates to a technique for stretching a filament by infrared heating, and there is an earlier application (International Publication No. WO2008 / 084797A1) related to stretching under reduced pressure. The present invention further improves these techniques so that it can be effectively applied to a PFA porous sheet.
なお、繊維径をナノオーダにまで細くする技術として、ＥＳ法（You Y., et, al　「Journal of Applied Polymer Science、ｖｏｌ．９５、ｐ．１９３－２００、２００５年」がある。しかし、ＥＳ法はポリマーを溶剤に溶かして高圧電圧をかける方法であり、ＰＦＡのように適当な溶剤が無い場合には適応できず、また、ＥＳ法によるウェブは、繊維径以上のダマが多く存在することも欠点となることが多かった。 As a technique for reducing the fiber diameter to nano-order, there is an ES method (You Y., et, al “Journal of Applied Polymer Science, vol.95, p.193-200, 2005”. However, the ES method. Is a method in which a polymer is dissolved in a solvent and a high voltage is applied. This method cannot be applied when there is no suitable solvent such as PFA. In addition, the web by the ES method has many lumps larger than the fiber diameter. There were many drawbacks.
国際公開公報ＷＯ２００８／０８４７９７Ａ１（第１－２頁、図１―３）International Publication No. WO2008 / 084797A1 (page 1-2, Fig. 1-3)
本発明は、本発明者の従来技術をさらに発展させたものであって、その目的とするところは、ＰＦＡ多孔質シートの強度を増し、比表面積を増して、安定した多孔質シートとして取り扱い易くしたものである。また他の目的は、ＰＦＡ多孔質シートを生産性良く安定して製造できる手段を提供することにある。 The present invention is a further development of the inventor's conventional technology. The purpose of the present invention is to increase the strength of the PFA porous sheet, increase the specific surface area, and facilitate handling as a stable porous sheet. It is a thing. Another object is to provide means for stably producing a PFA porous sheet with high productivity.
　本発明は上記の目的を達成するためになされたものであって、そのＰＦＡ多孔質シートとしての特徴は次の通りである。本発明は、前記ＰＦＡ多孔質シートが、平均フィラメント径が１０μｍ以下のＰＦＡからなるフィラメント群と、個々のフィラメントが平均フィラメント径以下のＰＦＡ微粒子を多数含むことを特徴とする、ＰＦＡ多孔質シートに関する。また本発明は、前記ＰＦＡフィラメントが１μｍ未満のｎｍの平均フィラメント径を有することを特徴とする、前記ＰＦＡ多孔質シートに関する。さらに本発明は、前記微粒子が融解されて、微粒子とフィラメント、および微粒子相互間が融着されていることを特徴とする、前記ＰＦＡ多孔質シートに関する。　 The present invention has been made to achieve the above object, and features as a PFA porous sheet are as follows. The present invention relates to a PFA porous sheet, wherein the PFA porous sheet includes a filament group composed of PFA having an average filament diameter of 10 μm or less, and a large number of PFA fine particles each of which has an average filament diameter of 1 or less. . The present invention also relates to the PFA porous sheet, wherein the PFA filament has an average filament diameter of nm of less than 1 μm. Furthermore, the present invention relates to the PFA porous sheet, wherein the fine particles are melted and the fine particles and the filaments and the fine particles are fused to each other. *
　また本発明は、上記ＰＦＡ多孔質を安定して製造する手段を提供するものであり、その製造手段としての特徴は次の通りである。本発明は、多錘のＰＦＡ原フィラメントがＰ１気圧下において送出手段によって送り出されて行く工程と、原フィラメント群がオリフィス中を通過して、Ｐ２気圧下（Ｐ１＞Ｐ２）の延伸室へ導かれる工程と、延伸室において、このオリフィスを通過してきた原フィラメント群が、炭酸ガスレーザービームを照射されることによって加熱され、Ｐ１からＰ２の気圧差によって生ずるオリフィスからの気体の流れによって生ずる牽引力によって延伸される工程と、延伸されたフィラメント群を集積する工程と、を有することによって平均フィラメント径が１０μｍ以下のＰＦＡフィラメント群と平均フィラメント径以下のＰＦＡ微粒子を多数含むシートとされることを特徴とする、ＰＦＡ多孔質シートの製造方法に関する。また本発明は、前記Ｐ１が大気圧であり、前記Ｐ２が減圧下であることを特徴とする、前記ＰＦＡ多孔質シートの製造方法に関する。また本発明は、前記オリフィスを出た多錘の原ＰＦＡフィラメント群が、延伸室全体を回転させることによってレーザービームが均一に当たる個所を探された後に、延伸を始められることを特徴とする、前記ＰＦＡ多孔質シートの製造方法に関する。また本発明は、前記炭酸ガスレーザービームの中心が、前記オリフィスの出口より３０ｍｍ以内で前記原フィラメントに照射されることを特徴とする、前記ＰＦＡ多孔質シートの製造方法に関する。また本発明は、前記炭酸ガスレーザービームビームが、前記原フィラメントの中心でフィラメントの軸方向に沿って上下４ｍｍ以内の範囲に照射されることを特徴とする、前記ＰＦＡ多孔質シートの製造方法に関する。また本発明は、前記延伸されたフィラメント群と多数の微粒子の集積が前記延伸室内で走行しているコンベアによって行われることを特徴とする、前記ＰＦＡ多孔質シートの製造方法に関する。また本発明は、前記延伸されたフィラメント群と多数の微粒子の集積が、前記延伸室内の巻取機の回転軸を中心に巻き取られ、この回転軸の外側に、延伸されたフィラメント群が降下してくる巾に対応した巾を持ち、回転軸に沿って湾曲している壁を有する捕集ガイドによってフィラメント群等を有効に回転軸に巻きつけるのを補助することを特徴とする、前記ＰＦＡ多孔質シートの製造方法に関する。さらに本発明は、前記微粒子を含む前記多孔質シートが、２７０℃以上で熱処理されることにより、この微粒子が融解して、該微粒子と該フィラメント、および微粒子相互間が融着されることを特徴とする、前記ＰＦＡ多孔質シートの製造方法に関する。 Further, the present invention provides means for stably producing the PFA porous material, and the features as the production means are as follows. In the present invention, a multi-filamentary PFA original filament is sent out by the feeding means under P1 atmospheric pressure, and the original filament group passes through the orifice and is led to a drawing chamber under P2 atmospheric pressure (P1> P2). In the process and the drawing chamber, the original filament group that has passed through the orifice is heated by being irradiated with the carbon dioxide laser beam, and drawn by the traction force generated by the gas flow from the orifice caused by the pressure difference between P1 and P2. And a step of accumulating the drawn filament group, whereby the sheet includes a PFA filament group having an average filament diameter of 10 μm or less and a large number of PFA fine particles having an average filament diameter of less than 10 μm. The present invention relates to a method for producing a PFA porous sheet. The present invention also relates to the method for producing a PFA porous sheet, wherein P1 is atmospheric pressure and P2 is under reduced pressure. Also, the present invention is characterized in that the original PFA filament group of multi-pillars exiting the orifice is started to be stretched after searching for a portion where the laser beam uniformly hits by rotating the entire stretching chamber, The present invention relates to a method for producing a PFA porous sheet. The present invention also relates to the method for producing a PFA porous sheet, wherein the original filament is irradiated within 30 mm from the outlet of the orifice at the center of the carbon dioxide laser beam. The present invention also relates to the method for producing a PFA porous sheet, wherein the carbon dioxide laser beam is irradiated to a range within 4 mm in the vertical direction along the axial direction of the filament at the center of the original filament. . The present invention also relates to the method for producing a PFA porous sheet, wherein the stretched filament group and a large number of fine particles are collected by a conveyor running in the stretch chamber. Further, according to the present invention, the stretched filament group and the accumulation of a large number of fine particles are wound around the rotating shaft of the winder in the stretching chamber, and the stretched filament group descends outside the rotating shaft. The PFA has a width corresponding to the width of the incoming wire, and assists in effectively winding a group of filaments around the rotating shaft by a collection guide having a wall curved along the rotating shaft. The present invention relates to a method for producing a porous sheet. Furthermore, the present invention is characterized in that when the porous sheet containing the fine particles is heat-treated at 270 ° C. or higher, the fine particles are melted and the fine particles, the filaments, and the fine particles are fused. And a method for producing the PFA porous sheet.
　本発明は、ＰＦＡフィラメントからなる多孔質シートに関する。ＰＦＡは、フッ素系ポリマーの１種で、ポリテトラフルオロエチレンに近い耐熱性を有し、耐薬品性が良く、優れた耐候性を示し、電気的諸特性にも優れ、表面が非粘着性で摩擦係数が小さいことなど、優れた特性を多く持っているので、それらの機能が要望される多くの分野で使用されている。特に１５０℃から２６０℃において優れた引張強度を有するので、溶融紡糸などの溶融成形が困難なＰＴＦＥに代わって、多くの分野で高機能のポリマーとして使用されている。なお、本発明のＰＦＡポリマーには、ＰＦＡを８５％（重量パーセント）以上含む場合を含んでいるものとする。これらの含有量は、赤外線分析装置等により決定される。 The present invention relates to a porous sheet made of a PFA filament. PFA is a type of fluoropolymer that has heat resistance close to that of polytetrafluoroethylene, good chemical resistance, excellent weather resistance, excellent electrical properties, and non-adhesive surface. Since it has many excellent properties such as a low friction coefficient, it is used in many fields where such functions are desired. In particular, it has excellent tensile strength at 150 ° C. to 260 ° C., and is used as a high-performance polymer in many fields in place of PTFE, which is difficult to be melt-molded such as melt spinning. In addition, the case where the PFA polymer of the present invention contains 85% (weight percent) or more of PFA is included. These contents are determined by an infrared analyzer or the like.
　本発明のＰＦＡ多孔質シートは、その構成するフィラメント群が１０μｍ以下のマイクロフィラメントであることを特徴とする。フィラメントは、実質的に連続した長さを有する繊維の１種であるが、通常、５０ｍｍ程度より小さく短繊維と呼ばれているものより長く、１００ｍｍ以上であり、特に本発明では、繊維径が小さいので、そのアスペクト比（長さ／径）は非常に大きい。本発明のフィラメントは、平均フィラメント径が１０μｍ以下のフィラメントからなることを特徴とし、望ましくは３μｍ以下、最も好ましくは１μｍに達しないナノフィラメントからなることを特徴とする。フィラメント径（平均フィラメント径）は、数千―１万倍の電子顕微鏡下で、１００本のフィラメントを数えて、算術平均して求める。本発明のフィラメント径が小さいことより、一定面積でのフィラメント数が大きくなり、また、比表面積の大きな多孔質シートとしての特徴がある。また本発明の多孔質シートは、他の微細繊維からなる多孔質シートであるＥＳ法から得られる不織布やメルトブロー不織布に比較して、フィラメント径が非常に均一であることも特徴の一つである。 The PFA porous sheet of the present invention is characterized in that the constituent filament group is a microfilament of 10 μm or less. The filament is a kind of fiber having a substantially continuous length, but is usually smaller than about 50 mm and longer than what is called a short fiber, and is 100 mm or more. Since it is small, its aspect ratio (length / diameter) is very large. The filaments of the present invention are characterized by comprising filaments having an average filament diameter of 10 μm or less, desirably 3 μm or less, and most preferably comprising nanofilaments that do not reach 1 μm. The filament diameter (average filament diameter) is obtained by arithmetically averaging 100 filaments under an electron microscope of several thousand to 10,000 times. Since the filament diameter of the present invention is small, the number of filaments in a certain area increases, and the porous sheet has a large specific surface area. In addition, the porous sheet of the present invention is also characterized in that the filament diameter is very uniform compared to the nonwoven fabric obtained from the ES method and the melt blown nonwoven fabric, which is a porous sheet composed of other fine fibers. .
不織布は、通常、何らかの繊維間の交絡を行ってシート状にされている多孔質シートである。本発明では、フィラメント径が非常に小さいので、単位重量あたりのＰＦＡフィラメント数が極端に多い。したがって、特に交絡工程を設けなくても、メルトブローン不織布同様、ＰＦＡフィラメントを集積する際にフィラメントが絡み合い、簡単なプレス程度でシート化されて使用することもできる。勿論、通常の不織布で行われている、熱エンボスやニードルパンチ、ウオータジェット、接着剤接合等の手段を用いることもでき、用途によって選択される。極細繊維不織布の大きな用途であるフィルター用途では、不織布をエレクトレット加工することで、捕集効率を桁違いに大きくすることができ、本発明の不織布も、エレクトレット加工してフィルター分野に向けることができる。 A non-woven fabric is a porous sheet that is usually formed into a sheet by entanglement between some fibers. In the present invention, since the filament diameter is very small, the number of PFA filaments per unit weight is extremely large. Therefore, even if the interlacing step is not particularly provided, the filaments are entangled when the PFA filaments are accumulated like the melt blown nonwoven fabric, and can be used after being formed into a sheet with a simple press. Of course, means such as hot embossing, needle punching, water jet, adhesive bonding, etc., which are performed with ordinary nonwoven fabrics, can also be used and are selected depending on the application. In filter applications, which is a major application of ultrafine fiber nonwoven fabrics, the collection efficiency can be increased by orders of magnitude by electret processing of the nonwoven fabric, and the nonwoven fabric of the present invention can also be electret processed and applied to the filter field .
ＰＦＡからなる多孔質シートは、そのポリマーが有する高機能を有する多孔質シートとして各方面で有用されている。特に、その耐薬品性が良いことや、電気的特性が良いことより、医療用分野や精密電気機器の分野で注目されている。それらの多孔質シートで、構成するＰＦＡフィラメントの繊維径を小さくし、１０μ以下のマイクロフィラメントにすることによって、多孔質シートが薄くなり、比表面積が増すので、より有用な素材として、それらの分野で要望されていた。しかし、ＰＦＡ多孔質シートは、その構成するポリマーの強度が強いにもかかわらず、ポリマーの非粘着性、摩擦係数が小さいことより、フィラメント間の摩擦係数が小さくために多孔質シートとしての強度が小さいことが問題となるケースがあった。 A porous sheet made of PFA is useful in various fields as a highly functional porous sheet of the polymer. In particular, it has attracted attention in the fields of medical use and precision electrical equipment due to its good chemical resistance and good electrical characteristics. By reducing the fiber diameter of the PFA filaments made of these porous sheets and making them microfilaments of 10 μm or less, the porous sheet becomes thinner and the specific surface area increases. It was requested in. However, the PFA porous sheet has high strength as a porous sheet because the non-adhesiveness of the polymer and the coefficient of friction are small, but the coefficient of friction between the filaments is small because the strength of the polymer constituting the PFA porous sheet is high. There was a case where smallness was a problem.
本発明の多孔質シートは、それを構成する個々のフィラメントとは別に、フィラメント径以下のＰＦＡ微粒子を多数含むことを特徴とする。通常のスパンボンド不織布やメルトブロー不織布などの紡糸直結型の不織布においては、ダマまたはショットと呼ばれるつぶ、又は粒子が存在する。しかし、これらのダマ等と呼ばれるものは、フィラメント径より数倍以上、通常、１０倍以上あり、不織布の欠陥として扱われる。本発明の微粒子は、径がフィラメント径より小さく、後記するように、多孔質シートにおいて種々の利点をもたらすものである。本発明における微粒子は通常球形で、その径（平均径）が多孔質シートを構成するフィラメント径（平均フィラメント径）以下であることを特徴とする。本発明における平均フィラメント径は、１０μｍ以下であること特徴とするので、その平均粒子径も１０μｍ以下であり、通常１μｍ未満で、数１０ｎｍから数１００ｎｍの径を有するナノ粒子からなる。このように本発明の微粒子は粒子径が小さいので、本発明の多孔質シートの比表面積を非常に大きくすることに貢献する。粒子径（平均粒子径）は、数千―１万倍の電子顕微鏡下で、顕微鏡下に示される寸法ゲージにより、１００個の粒子の径を測定して算術平均で求める。また、多数とは、「１０，０００倍の電顕視野下で、１本のフィラメントに対して複数の微粒子が確認されることをいう。多数存在することによって、微粒子とフィラメント間、または微粒子相互間が融着することによって、本発明の目的である多孔質シートの強度アップや比表面積の増大などの効果が期待できないからである。さらに本発明における微粒子は、その粒子径が揃っていることも特徴の一つで、このこともスパンボンド不織布やメルトブロー不織布の「だま」あるいはショットとは異なる点である。 The porous sheet of the present invention includes a large number of PFA fine particles having a diameter equal to or less than the filament diameter, in addition to the individual filaments constituting the porous sheet. In a direct-spun type nonwoven fabric such as a normal spunbond nonwoven fabric or a melt blown nonwoven fabric, crushing or particles called dama or shot are present. However, these so-called lumps and the like are several times larger than the filament diameter, usually 10 times larger, and are treated as defects of the nonwoven fabric. The fine particles of the present invention have a diameter smaller than the filament diameter, and provide various advantages in the porous sheet as described later. The fine particles in the present invention are usually spherical, and the diameter (average diameter) is not more than the filament diameter (average filament diameter) constituting the porous sheet. Since the average filament diameter in the present invention is 10 μm or less, the average particle diameter is also 10 μm or less, and it is usually less than 1 μm and consists of nanoparticles having a diameter of several tens to several hundreds of nm. As described above, the fine particles of the present invention have a small particle size, which contributes to a very large specific surface area of the porous sheet of the present invention. The particle diameter (average particle diameter) is obtained by arithmetic average by measuring the diameter of 100 particles with a dimensional gauge shown under the microscope under an electron microscope of several thousand to 10,000 times. The term “multiple” means that a plurality of fine particles are confirmed with respect to one filament under a 10,000 × electron microscope field of view. It is because the effect of increasing the strength of the porous sheet or increasing the specific surface area, which is the object of the present invention, cannot be expected due to the fusion of the gaps. Is another feature, which is also different from “dama” or shots of spunbond nonwoven fabrics and meltblown nonwoven fabrics.
　本発明におけるＰＦＡ微粒子は、熱処理されることにより融解されて、微粒子とフィラメント、および微粒子相互間が融着されて、多孔質シートとして一体化されていることを特徴とする。非粘着で摩擦係数の小さいＰＦＡフィラメントからなる多孔質シートも、このように融着されて一体化されることにより、シートとしての引張強度を高め、寸法安定性のあるシートとなる。 The PFA fine particles in the present invention are melted by heat treatment, and the fine particles and the filaments and the fine particles are fused together to be integrated as a porous sheet. A porous sheet made of PFA filaments which are non-adhesive and have a small coefficient of friction is also fused and integrated in this way, thereby increasing the tensile strength of the sheet and providing a sheet with dimensional stability.
本発明のＰＦＡ多孔質シートは、本発明者の先願発明である特許文献１の炭酸ガスレーザービームとオリフィス間の気圧差を利用したフィラメントの超高倍率延伸手段をＰＦＡフィラメントに応用したものである。ＰＦＡ原フィラメントは、数１０μｍから数１００μｍの太いフィラメント径から、数万倍から数十万倍に超延伸されて、数ミクロンメータから数十ｎｍに至る極細フィラメントとなり、延伸されたフィラメント群は集積されて、多孔質シートとなる。本発明におけるＰＦＡ原フィラメントとは、既にフィラメントとして製造されて、リール等に巻き取られたものである。また紡糸過程において、溶融または溶解フィラメントが冷却や凝固によりフィラメントとなったものを紡糸過程に引き続き使用され、本発明の原フィラメントとしうる。ここでフィラメントとは、実質的に連続した繊維であり、数ｍｍから数十ｍｍの長さである短繊維とは区別される。原フィラメントは、単独で存在することが望ましいが、数本ないし数十本に集合されていても使用することができる。 The PFA porous sheet of the present invention is an application of the ultra-high magnification drawing means for filaments utilizing the pressure difference between the carbon dioxide laser beam and the orifice of Patent Document 1, which is the invention of the present inventor, to the PFA filament. is there. PFA raw filaments are super-stretched from several tens of micrometers to several hundreds of micrometers in diameter and from several tens of thousands to several hundreds of thousands of times to become ultrafine filaments ranging from several micrometers to several tens of nanometers. Thus, a porous sheet is obtained. The PFA original filament in the present invention is already manufactured as a filament and wound on a reel or the like. Further, in the spinning process, a melted or melted filament that has become a filament by cooling or coagulation is used subsequently in the spinning process, and can be used as the original filament of the present invention. Here, the filament is a substantially continuous fiber, and is distinguished from a short fiber having a length of several mm to several tens of mm. The original filament is desirably present alone, but it can be used even if it is assembled into several to several tens.
  本発明においは、フィラメントの送出手段から送り出された原フィラメントについて延伸が行われる。送出手段は、ニップローラや数段の駆動ローラの組み合わせなどの一定の送出速度でフィラメントを送り出すことが出来るものであれば種々のタイプのものが使用できる。  In the present invention, the original filament sent out from the filament sending means is stretched. As the delivery means, various types can be used as long as the filament can be delivered at a constant delivery speed, such as a combination of a nip roller and several stages of driving rollers.
多錘のＰＦＡ原フィラメントがＰ１気圧下で送出手段によって送り出されて、オリフィス中を通過して、Ｐ２気圧下（Ｐ１＞Ｐ２）の延伸室へ導かれ。オリフィスを通過してきた原フィラメント群が、炭酸ガスレーザービームを照射されることによって加熱され、Ｐ１からＰ２の気圧差によって生ずる気体の流れによって生ずる牽引力によって延伸される。なお、この原フィラメント群が送り出されてくる際の圧力Ｐ１が大気圧であり、延伸室における圧力Ｐ２が減圧下であることは、装置を簡便にできるので、好ましい態様の一つである。Ｐ１を加圧下、Ｐ２を減圧下にすると、Ｐ２の減圧度をそれほど大きくすることなく、Ｐ１とＰ２の差圧を大きくできるので、これも好ましい態様の一つである。なお延伸室は、オリフィスの出口で、レーザービームによって原ＰＦＡフィラメントが延伸される狭義の延伸室と、延伸されたフィラメントが集積される狭義のフィラメント集積室に分ける場合もあるが、狭義の延伸室と狭義のフィラメント集積室は一体的に結合されて、同一気圧に保たれ、広義の延伸室を構成している。 The multifilamentary PFA original filament is sent out by the feeding means under P1 atmospheric pressure, passes through the orifice, and is led to the drawing chamber under P2 atmospheric pressure (P1> P2). The original filament group that has passed through the orifice is heated by being irradiated with a carbon dioxide laser beam, and is stretched by a traction force generated by a gas flow generated by a pressure difference between P1 and P2. In addition, it is one of the preferable aspects since the apparatus can be simplified that the pressure P1 when the original filament group is sent out is atmospheric pressure and the pressure P2 in the drawing chamber is under reduced pressure. When P1 is pressurized and P2 is depressurized, the differential pressure between P1 and P2 can be increased without increasing the degree of P2 depressurization so much, which is also a preferred embodiment. The stretching chamber may be divided into a narrowly defined stretching chamber in which the original PFA filaments are stretched by a laser beam at the exit of the orifice, and a narrowly defined filament collecting chamber in which the stretched filaments are collected. And the filament collecting chamber in a narrow sense are integrally coupled and kept at the same atmospheric pressure to form a stretching chamber in a broad sense.
　なおＰ１またはＰ２は、通常室温の空気が使用される。しかし、原フィラメントを予熱したい場合や、延伸したフィラメントを熱処理したい場合は、加熱エアーが使用される場合もある。 Note that air at room temperature is usually used for P1 or P2. However, heated air is sometimes used when preheating the original filament or when heat treating the drawn filament.
　本発明における原フィラメント供給室と延伸室は、オリフィスによってつながっている。オリフィス中では、原フィラメントとオリフィス内径との間の狭い隙間に、Ｐ１＞Ｐ２の圧力差で生じた高速気体の流れが生じる。この高速気体の流れを生じるために、オリフィスの内径Ｄと繊維の径ｄとは、あまり大きくかけはなれてはならない。実験結果、Ｄ＞ｄであって、Ｄ＜３０ｄ、好ましくはＤ＜１０ｄ、さらに好ましくはＤ＜５ｄであってＤ＞２ｄであることが最も好ましい。 In the present invention, the original filament supply chamber and the drawing chamber are connected by an orifice. In the orifice, a high-speed gas flow generated by a pressure difference of P1> P2 is generated in a narrow gap between the original filament and the orifice inner diameter. In order to generate this high-speed gas flow, the inner diameter D of the orifice and the diameter d of the fiber should not be too large. Experimental results show that D> d, D <30d, preferably D <10d, more preferably D <5d and D> 2d.
　上記におけるオリフィス内径Ｄは、オリフィスの出口部における径をいう。但し、オリフィス断面が円では無い場合、一番狭い部分の径をＤとする。同様に、フィラメントの径も、断面が円ではない場合、一番小さい径の値をｄとし、断面の最も小さい箇所を基準に１０カ所を測定して算術平均する。また、オリフィスの内径は、均一な径ではなく、テーパ状で出口において狭くなる形状も好ましい。なお、オリフィスの出口は、通常、原フィラメントが上から下へ通過するので、縦に配置されたオリフィスの下方が出口となるが、下から上へ原フィラメントが通過する場合は、オリフィスの上方に出口がある。同様に、オリフィスが横に配置されて、原フィラメントが横方向に通過する場合は、オリフィスの横方向に出口がある。 The above-mentioned orifice inner diameter D is the diameter at the outlet of the orifice. However, if the orifice cross section is not a circle, the diameter of the narrowest part is D. Similarly, when the cross section of the filament is not a circle, the smallest diameter value is d, and 10 points are measured and averaged based on the smallest cross section. In addition, the inner diameter of the orifice is not a uniform diameter but is preferably tapered and narrowed at the outlet. In addition, since the original filament usually passes from the top to the bottom at the outlet of the orifice, the lower part of the vertically arranged orifice is the outlet, but when the original filament passes from the bottom to the top, it is above the orifice. There is an exit. Similarly, if the orifice is placed laterally and the original filament passes laterally, there is an outlet transverse to the orifice.
　上記のように、オリフィス内を高速の気体が流れるので、オリフィスの内部は抵抗の少ない構造が望ましい。本発明のオリフィスの形状は、１本１本独立したものも使用されるが、板状物に多数の孔を開けて多錘のオリフィスとすることもできる。オリフィスの内部の断面も円形のものが望ましいが、複数のフィラメントを通過させる場合や、フィラメントの形状が楕円やテープ状の場合には、断面が楕円や矩形のものも使用される。また、オリフィス入り口では、原フィラメントを導入しやすいように大きく、出口部分のみ狭い形状が、フィラメントの走行抵抗を小さくし、オリフィスの出口からの風速も大きくできるので好ましい。　　　 As mentioned above, since a high-speed gas flows through the orifice, it is desirable that the orifice has a low resistance structure. The orifices according to the present invention may be used independently of each other, but a large number of orifices may be formed by opening a large number of holes in a plate-like object. A circular cross section inside the orifice is desirable, but when a plurality of filaments are allowed to pass, or when the filament has an oval or tape shape, an oval or rectangular cross section is also used. Further, it is preferable that the orifice entrance is large so that the original filament can be easily introduced and only the exit portion is narrow because the running resistance of the filament can be reduced and the wind speed from the exit of the orifice can be increased. *
　本発明におけるオリフィスは、本発明人らによる従来の延伸前の送風管とは役割を異にしている。従来の送風管は、レーザーをフィラメントの定位置に当てる役目であり、できるだけ抵抗少なく、定位置に原フィラメントを搬送する役目であった。本発明はそれにプラスすることの、高速の気体流が原フィラメント供給室の気圧Ｐ１と延伸室の気圧Ｐ２の気圧差によって発生する点で異なる。なお、通常のスパンボンド不織布製造においては、エアーサッカー等によって溶融フィラメントに張力を与えられる。しかし、スパンボンド不織布製造におけるエアーサッカーと本発明におけるオリフィスとは、その作用機構と効果が全く異なる。スパンボンド法では、溶融フィラメントをエアーサッカー内の高速流体で送られ、エアーサッカー内でそのフィラメント径の細化の殆どが完了する。それに対して、本発明では固体の原フィラメントがオリフィスで送られ、オリフィス内ではフィラメントの細化は始まらず、オリフィスを出た所でレーザービームが照射されることによって、始めて延伸が開始される。またスパンボンド法では、エアーサッカー内に高圧エアーを送りこむことにより高速流体を発生させるが、本発明では、オリフィス前後における部屋の気圧差でオリフィス内の高速流体を発生させる点で異なる。またその効果も、スパンボンド法では、せいぜい１０μｍ前後のフィラメント径しか得られないのに対して、本発明では１μｍ未満のナノフィラメントが得られるという大きな効果が得られる点が異なる。 The orifice in the present invention has a role different from that of the conventional blower pipe before stretching by the present inventors. The conventional blower tube has a role of applying a laser to a fixed position of the filament, and has a function of conveying the original filament to the fixed position with as little resistance as possible. The present invention is different from that in that a high-speed gas flow is generated due to a difference in pressure between the pressure P1 in the original filament supply chamber and the pressure P2 in the drawing chamber. In normal spunbond nonwoven fabric production, tension is applied to the molten filament by air soccer or the like. However, the air soccer in the production of the spunbonded nonwoven fabric and the orifice in the present invention are completely different in operation mechanism and effect. In the spunbond method, the molten filament is fed by a high-speed fluid in the air soccer, and most of the filament diameter is reduced in the air soccer. On the other hand, in the present invention, the solid original filament is sent by the orifice, and the filament does not start to be thinned in the orifice, but is first drawn by being irradiated with the laser beam at the exit from the orifice. In the spunbond method, high-speed fluid is generated by sending high-pressure air into the air soccer. However, the present invention is different in that high-speed fluid is generated in the orifice due to the pressure difference between the rooms before and after the orifice. In addition, the spunbond method is different in that only a filament diameter of about 10 μm can be obtained at most, whereas the present invention provides a great effect that nanofilaments of less than 1 μm can be obtained.
　本発明においては、オリフィス内での流速は、５０ｍ／ｓｅｃ以上であることが好ましく、１００ｍ／ｓｅｃ以上であることがさらに好ましく、最も好ましくは、２００ｍ／ｓｅｃ以上である。これらの流速は、原料フィラメントの素材、目的とするフィラメント径等によって決められる。 In the present invention, the flow velocity in the orifice is preferably 50 m / sec or more, more preferably 100 m / sec or more, and most preferably 200 m / sec or more. These flow rates are determined by the raw material filament material, the target filament diameter, and the like.
　オリフィスから送り出されてきた原フィラメントは、オリフィスの出口で、炭酸ガスレーザービームによって加熱され、オリフィスからの高速流体によってフィラメントに与えられる張力によって、原フィラメントは延伸される。オリフィスの直下とは、実験結果、炭酸ガスレーザービームの中心がオリフィス先端より３０ｍｍ以下、好ましくは１０ｍｍ以下、５ｍｍ以下であることが最も好ましい。オリフィスから離れると、原フィラメントが振れ、定位置に収まらず、炭酸ガスレーザービームに安定して捉えられないからである。またオリフィスからの高速気体によってフィラメントに与えられる張力が、オリフィスから離れることによって弱くなり、また安定性も小さくなるからと思われる。 The original filament sent out from the orifice is heated by the carbon dioxide laser beam at the outlet of the orifice, and the original filament is drawn by the tension applied to the filament by the high-speed fluid from the orifice. “Directly under the orifice” means that, as a result of experiments, the center of the carbon dioxide laser beam is 30 mm or less, preferably 10 mm or less, preferably 5 mm or less from the tip of the orifice. This is because when the filament is separated from the orifice, the original filament swings and does not stay in a fixed position and cannot be stably captured by the carbon dioxide laser beam. Further, it is considered that the tension applied to the filament by the high-speed gas from the orifice is weakened by moving away from the orifice, and the stability is also reduced.
　本発明は、原フィラメントが炭酸ガスレーザービームによって加熱されて延伸されることを特徴とする。本発明の炭酸ガスレーザービームは、１０．６μｍ前後の波長を有している。レーザーは、照射範囲（ビーム）を小さく絞り込むことが可能であり、また、特定の波長に集中しているので、無駄なエネルギーも少ない。本発明の炭酸ガスレーザーは、パワー密度が５０Ｗ／ｃｍ2以上、好ましくは１００Ｗ／ｃｍ2以上、最も好ましくは、１８０Ｗ／ｃｍ2以上である。狭い延伸領域に高パワー密度のエネルギーを集中することによって、本発明の超高倍率延伸が可能となるからである。  The present invention is characterized in that the original filament is heated and drawn by a carbon dioxide laser beam. The carbon dioxide laser beam of the present invention has a wavelength of around 10.6 μm. The laser can narrow down the irradiation range (beam) and is concentrated on a specific wavelength, so that there is little wasted energy. The carbon dioxide laser of the present invention has a power density of 50 W / cm 2 or more, preferably 100 W / cm 2 or more, and most preferably 180 W / cm 2 or more. This is because the ultrahigh magnification stretching of the present invention can be achieved by concentrating energy of high power density in a narrow stretching region.
本発明の原フィラメントは、炭酸ガスレーザービームにより延伸適温に加熱されるが、延伸適温に加熱される範囲がフィラメントの中心でフィラメントの軸方向に沿って、上下４ｍｍ（長さ８ｍｍ）以内であることが好ましく、さらに好ましくは上下３ｍｍ以下、最も好ましくは上下２ｍｍ以下で加熱される。このビームの径は、走行するフィラメントの軸方向に沿って測定する。本発明においては、原フィラメントが複数本であるので、原フィラメントの軸方向で測定される。本発明は、狭い領域で急激に延伸されることにより、高度に極細化され、ナノ領域までに細くした延伸を可能にし、しかも超高倍率延伸であっても、延伸切れを少なくすることができた。なお、この炭酸ガスレーザービームが照射されるフィラメントがマルチフィラメントである場合は、上記のフィラメントの中心は、マルチフィラメントのフィラメント束の中心を意味する。　 The original filament of the present invention is heated to a suitable temperature for stretching by a carbon dioxide laser beam, but the range heated to the suitable temperature for stretching is within 4 mm (length: 8 mm) in the vertical direction along the axial direction of the filament at the center of the filament. More preferably, the heating is performed at a top and bottom of 3 mm or less, most preferably at a top and bottom of 2 mm or less. The beam diameter is measured along the axial direction of the traveling filament. In the present invention, since there are a plurality of original filaments, the measurement is performed in the axial direction of the original filaments. The present invention makes it possible to stretch highly narrowed to a nano region by being rapidly stretched in a narrow region, and to reduce stretch breaks even with ultra-high magnification stretching. It was. When the filament irradiated with the carbon dioxide laser beam is a multifilament, the center of the filament means the center of a multifilament filament bundle. *
　オリフィスを出た多錘の原ＰＦＡフィラメント群は、レーザービームを照射されることによって延伸される。その際、多錘の原フィラメント群に均一にレーザービームが当たる必要がある。その手段として、延伸室全体を微細に回転させながら原フィラメント群の全てが均一に延伸される好適な位置を探る。その好適な回転位置において延伸を始めることが好ましい。なお、延伸室全体は、回転ばかりでなく、横方向（Ｘ方向）、ビームの照射方向（Ｙ方向）、高さ方向（Ｚ方向）へも微細に移動させることで、好適な位置が探られる。 The multi-element original PFA filament group exiting the orifice is stretched by being irradiated with a laser beam. At that time, it is necessary to uniformly irradiate the multi-filamentary original filament group with the laser beam. As a means for this, a suitable position where all the original filament groups are uniformly stretched is searched while the entire stretching chamber is rotated finely. It is preferred to begin stretching at its preferred rotational position. It should be noted that the entire stretching chamber is not only rotated, but is also finely moved in the lateral direction (X direction), the beam irradiation direction (Y direction), and the height direction (Z direction) to find a suitable position. .
　本発明の延伸されたフィラメントの集積装置として、走行するコンベアが使用される。コンベア上に集積され、積層されることによって、極細フィラメントの集積体または多孔質シートとして巻き取ることもできる。このようにすることにより、ナノフィラメントからなる多孔質シートを製造することができる。本発明のコンベアとして、網状の移動体が通常使用されるが、ベルトやシリンダ上に集積させてもよい。 A traveling conveyor is used as the stretched filament accumulation device of the present invention. By collecting and laminating on a conveyor, it can be wound up as an aggregate of fine filaments or a porous sheet. By doing in this way, the porous sheet which consists of nanofilaments can be manufactured. As the conveyor of the present invention, a net-like moving body is usually used, but it may be accumulated on a belt or a cylinder.
　また、本発明によって延伸された多錘の極細フィラメントは、走行している布状物上に集積されることによって、この布状物と積層された積層体を製造することができる。特に、ナノフィラメントからなる集積体または多孔質シートは、構成するフィラメントが非常に細いために取り扱いが困難であるが、このように布状物と積層されることにより取り扱いが安定する。また用途においても、市販のスパンボンド多孔質シート等と積層されることにより、フィルター等の用途にそのまま使用することもできる。布状物として、織物、編物、不織布、フェルト、紙などが使用される。また、フィルムを走行させてその上に集積させてもよい。  Further, the multi-filamentary ultrafine filaments stretched according to the present invention are accumulated on the traveling cloth-like material, so that a laminated body laminated with the cloth-like material can be manufactured. In particular, an aggregate or a porous sheet made of nanofilaments is difficult to handle because the filaments constituting it are very thin, but the handling is stabilized by being laminated with a cloth-like material in this way. Moreover, also in a use, it can also be used as it is for uses, such as a filter, by laminating | stacking with a commercially available spunbond porous sheet. As the cloth-like material, woven fabric, knitted fabric, non-woven fabric, felt, paper or the like is used. Alternatively, the film may be run and accumulated on it.
　本発明の延伸されたフィラメントの集積装置として、フィラメント群やシート等の巻取装置も使用される。延伸されて下降してくるフィラメント群の巾に相当した紙管やアルミ管の管状物が回転軸として取り付けられた巻取機で、これらの管状物の上に延伸されたフィラメントは集積され、捕集されて巻き取られていく。 As the stretched filament accumulating device of the present invention, a winding device such as a filament group or a sheet is also used. A take-up machine in which a tubular body of paper or aluminum tube corresponding to the width of the filament group that has been stretched and descended is attached as a rotating shaft. The filaments stretched on these tubular bodies are collected and collected. It is collected and rolled up.
　本発明の集積装置として巻取機を用いた場合、巻取軸に沿って湾曲している壁からなる捕集ガイドを設けることが望ましい。この捕集ガイドは、回転軸の外側に多錘の延伸されたフィラメント群が降下してくる巾に対応した巾を持つ。対応した巾とは、フィラメント群が下降して巾より広く、好ましくは５０ｍｍ前後、さらに好ましくは１００ｍｍ前後に両側に広いことが最も好ましい。オリフィスから高速エアーと共に走行してくる延伸されたフィラメントが巻取軸に巻きつかれて行く場合、高速エアーが巻取軸で反射して周囲へ飛散し、巻取軸上のフィラメントの集積状態が乱れる場合があるが、この捕集ガイドの壁によって高速エアーが巻取機の回転軸方向に曲げられ、延伸されたフィラメントの飛散を防ぐことができる。巻取軸から捕集ガイドの壁までの距離は、５００ｍｍ以下、好ましくは２００ｍｍ以下、１００ｍｍ以下であることが最も好ましい。 When a winder is used as the stacking device of the present invention, it is desirable to provide a collection guide made of a wall that is curved along the winding shaft. This collection guide has a width corresponding to the width by which the multifilamentary extended filament group descends outside the rotating shaft. The corresponding width is most preferably wider than the width when the filament group descends, preferably around 50 mm, more preferably around 100 mm on both sides. When stretched filaments that run along with high-speed air from the orifice are wound around the take-up shaft, the high-speed air is reflected by the take-up shaft and scattered around, disturbing the state of filament accumulation on the take-up shaft. In some cases, the high-speed air is bent in the direction of the rotation axis of the winder by the wall of the collection guide, and the stretched filaments can be prevented from scattering. The distance from the winding shaft to the wall of the collection guide is most preferably 500 mm or less, preferably 200 mm or less, and 100 mm or less.
　コンベア上に集積された延伸されたフィラメント群は、熱処理されてシートを形成されることが望ましい。このように熱処理されることにより本発明の微粒子が融解し、寸法安定性と熱安定性を備えた多孔質シートとすることができる。そして、この多孔質シートは、延伸室内に設けられているシート巻取装置に巻き取られることが望ましい。熱処理は、熱風循環されている空間中に多孔質シートを通過させることや、誘導加熱等で加熱されているロール上を通過させることで行われる。本発明のＰＦＡ多孔質シートの熱処理温度は少なくと２７０℃以上であることにより、微粒子が融解されて、微粒子とフィラメント、および微粒子相互間が融着されて、引張強度が高く寸法安定性の高いＰＦＡ多孔質シートとなる。 The stretched filament group accumulated on the conveyor is preferably heat treated to form a sheet. By being heat-treated in this manner, the fine particles of the present invention are melted, and a porous sheet having dimensional stability and thermal stability can be obtained. The porous sheet is preferably wound around a sheet winding device provided in the stretching chamber. The heat treatment is performed by allowing the porous sheet to pass through a space in which hot air is circulated, or by passing it over a roll that is heated by induction heating or the like. When the heat treatment temperature of the PFA porous sheet of the present invention is at least 270 ° C. or more, the fine particles are melted, the fine particles, the filaments, and the fine particles are fused together, and the tensile strength is high and the dimensional stability is high. It becomes a PFA porous sheet.
　本発明において延伸されたフィラメントは、全てフィラメントと表現するが、延伸された結果、上記ファイバーの領域に属するものも含まれる。本発明における延伸されたフィラメントは、殆どの場合、延伸切れすることなく数分以上延伸されるので、フィラメントの長さも数ｍ以上であり、フィラメント径ｄが小さいことを考慮すると、実質的に連続フィラメントと見なすことができる場合が殆どである。しかし、条件によっては、上記ファイバーの領域に属する短繊維も製造することができる。 In the present invention, the drawn filaments are all expressed as filaments, but include those belonging to the fiber region as a result of drawing. In most cases, the stretched filament in the present invention is stretched for several minutes without being stretched. Therefore, considering the fact that the length of the filament is several meters or more and the filament diameter d is small, it is substantially continuous. In most cases, it can be regarded as a filament. However, depending on conditions, short fibers belonging to the above-mentioned fiber region can also be produced.
本発明における多孔質シートは、延伸されたＰＦＡ極細フィラメントを走行するコンベア上や巻取軸上に集積することによって製造される。極細フィラメントからなる多孔質シートは、不織布と表現してもよいが、本発明では微粒子を伴い、不織布とは異なる側面も有するので、多孔質シートと表現したが、不織布と同様の形態や機能も有する。不織布は近年、単に織物の代替というだけではなく、不織布独特の特性が注目されて、種々の業界で需要が活発化している。その中で、極細繊維の多孔質シートとして、メルトブローン不織布があり、溶融フィラメントを熱風で吹き飛ばすことで３μｍ前後のフィラメントとし、コンベア上に集積させて多孔質シートにしたものが、エアーフィルターを中心に使用されている。しかし、このメルトブローン不織布を構成するフィラメントは、０．１ｃＮ／ｄｔｅｘ前後と、通常の未延伸繊維よりも弱い強度であり、また、ショットまたはダマと呼ばれる樹脂の小さい塊が多数存在する欠点も有する。本発明の延伸されたＰＦＡフィラメントからなる多孔質シートは、メルトブローン不織布と同様の３μｍ前後のフィラメント径や、さらにそれ以下のナノフィラメントの領域までのフィラメント径を有していながら、ＰＦＡフィラメントが高度に分子配向しているので、通常の延伸された合成繊維に近い強度を有している。しかも、ショットやダマを全く含まない多孔質シートとすることができる。本発明の多孔質シートは、極細フィラメントであることによる緻密な生地や光沢、軽量、断熱、撥水などの性能アップの効果を有する。また本発明のＰＦＡフィラメントからなる多孔質シートは、フィラメント径が細くて均一なため、比表面積が大きいという特徴を有する。なお、背景技術の項で記載したように、ＰＦＡフィラメントからなるスパンボンド不織布については、従来種々検討されているが、本発明のフィラメントは、それらのスパンボンド不織布より、強度があってフィラメント径が小さい。 The porous sheet in the present invention is manufactured by accumulating stretched PFA ultrafine filaments on a conveyor or a winding shaft. Although a porous sheet made of ultrafine filaments may be expressed as a nonwoven fabric, in the present invention, it is expressed as a porous sheet because it has fine particles and has a side surface different from that of the nonwoven fabric. Have. In recent years, non-woven fabrics are not only a substitute for woven fabrics, but also the unique properties of non-woven fabrics have attracted attention, and the demand for various non-woven fabrics has increased. Among them, there is a melt-blown nonwoven fabric as a porous sheet of ultrafine fibers. A filament of around 3 μm is obtained by blowing molten filaments with hot air, and it is accumulated on a conveyor to form a porous sheet, mainly an air filter. in use. However, the filament constituting the meltblown nonwoven fabric has a strength of around 0.1 cN / dtex, which is weaker than that of a normal unstretched fiber, and also has a defect that there are many small lumps of resin called shots or lumps. The porous sheet composed of the stretched PFA filament of the present invention has a filament diameter of about 3 μm, which is the same as that of the meltblown nonwoven fabric, and a filament diameter up to a nanofilament region smaller than that, but the PFA filament is highly Since it is molecularly oriented, it has a strength close to that of a normal stretched synthetic fiber. Moreover, a porous sheet containing no shots or lumps can be obtained. The porous sheet of the present invention has an effect of improving performance such as dense fabric and gloss, light weight, heat insulation, water repellency and the like due to being an ultrafine filament. In addition, the porous sheet made of the PFA filament of the present invention is characterized by a large specific surface area because the filament diameter is thin and uniform. As described in the background art section, various spunbond nonwoven fabrics made of PFA filaments have been studied in the past, but the filaments of the present invention are stronger than those spunbond nonwoven fabrics and have a filament diameter. small.
　本発明は炭酸ガスレーザービームによって、原フィラメントを超高倍率に延伸することによって、極細フィラメントを製造することを目的とする。本発明における極細フィラメントは、原フィラメントが１００倍以上に延伸されて極細化されたフィラメントをいう。その極細フィラメントのうち、フィラメント径が１μｍ未満のものを特にナノフィラメントという。本発明においては、原フィラメントを延伸倍率が１０，０００倍以上にすることにより、１００μｍ以上の径の原フィラメントからでもナノフィラメントが得ることができる点に特徴がある。 An object of the present invention is to produce an ultrafine filament by stretching an original filament at an ultrahigh magnification with a carbon dioxide laser beam. The ultrafine filament in the present invention refers to a filament that is made ultrafine by stretching the original filament 100 times or more. Among the ultrafine filaments, those having a filament diameter of less than 1 μm are particularly called nanofilaments. The present invention is characterized in that nanofilaments can be obtained even from original filaments having a diameter of 100 μm or more by making the original filament have a draw ratio of 10,000 times or more.
　本発明における延伸倍率λは、原フィラメントの径ｄｏと延伸後のフィラメントの径ｄより、下記の式で表される。この場合、フィラメントの密度は一定として計算する。繊維径の測定は、走査型電子顕微鏡（ＳＥＭ）で、原フィラメントは３５０倍、延伸されたフィラメントは１０００倍またはそれ以上の倍率での撮影写真に基づき、１００点の平均値で行う。
　　　λ＝（ｄo／ｄ）2 The draw ratio λ in the present invention is represented by the following formula from the diameter do of the original filament and the diameter d of the filament after drawing. In this case, the density of the filament is calculated as constant. The fiber diameter is measured with a scanning electron microscope (SEM) using an average value of 100 points based on a photograph taken at a magnification of 350 times for the original filament and 1000 times or more for the drawn filament.
λ = (do / d) 2
　本発明における延伸フィラメントは、フィラメント径が揃っていることを特徴とする。フィラメント径分布は、上記ＳＥＭ写真から測長用ソフトでフィラメント径を１００箇測定して求めた。またそれらの測定値より、標準偏差を求め、フィラメント径分布の尺度とした。また、この測定法によりフィラメント径の平均値が求めらている場合は、本発明の平均フィラメント径として採用する。 The drawn filaments according to the present invention are characterized by uniform filament diameters. The filament diameter distribution was obtained by measuring 100 filament diameters from the above SEM photograph using length measurement software. Moreover, the standard deviation was calculated | required from those measured values, and it was set as the scale of filament diameter distribution. Moreover, when the average value of a filament diameter is calculated | required by this measuring method, it employ | adopts as an average filament diameter of this invention.
　本発明における延伸フィラメントは延伸されることにより分子配向し、熱的にも安定している。本発明の延伸フィラメントはフィラメント径が非常に小さいので、フィラメントの分子配向を測定することは困難である。本発明の延伸フィラメントは、単に細くなっただけではなく、分子配向も生じていることが、熱分析の結果により示唆されている。原フィラメントや延伸フィラメントの示差熱分析（ＤＳＣ）測定は、株式会社リガク製ＴＨＥＭ　ＰＬＵＳ２　ＤＳＣ８２３０Ｃにより、昇温速度１０℃／ｍｉｎで測定した。 The drawn filament in the present invention is molecularly oriented by being drawn and is thermally stable. Since the drawn filament of the present invention has a very small filament diameter, it is difficult to measure the molecular orientation of the filament. The results of thermal analysis suggest that the drawn filament of the present invention is not only thinned but also has molecular orientation. The differential thermal analysis (DSC) measurement of the original filament and the drawn filament was carried out at a heating rate of 10 ° C./min using a THEM PLUS2 DSC8230C manufactured by Rigaku Corporation.
本発明は、マイクロフィラメントからなるＰＦＡ多孔質シートにおいて、ＰＦＡ微粒子を伴うことを特徴とする。この微粒子はフィラメント径より小さいので、多孔質シートとしての比表面積が大きくなる。比表面積は、単位重量当たりの表面積である。本発明の微粒子はフィラメント径より小さく、通常、フィラメント径の１／１０から１／５の径であることより、必然的に比表面積が大きくなる。 The present invention is characterized in that a PFA porous sheet made of microfilaments is accompanied by PFA fine particles. Since the fine particles are smaller than the filament diameter, the specific surface area of the porous sheet is increased. The specific surface area is a surface area per unit weight. The fine particles of the present invention are smaller than the filament diameter, and usually have a specific surface area of 1/10 to 1/5 of the filament diameter.
本発明のＰＦＡ微粒子は、融解することにより、微粒子とフィラメント、また微粒子相互間を接合する接着剤効果として機能し、多孔質シートの機械的強度アップに寄与する。従来、不織布のフィラメント間接合を強化する目的で、接着剤が使用されている。しかし、後から接着剤を付与する方法では、コストアップであり、また、エマルジョンや溶剤系の接着剤では、多孔質シート全体に膜が張り、通気性を損ねる欠点となる。また、粉末系の接着剤では、微粉末の接着剤はフッ素系では存在しないし、存在してもコストが高い、さらにこの粉末接着剤を多孔質シートに均一付着することが困難である。それに対して、本発明のＰＦＡ微粒子は、多孔質シートに本来的に付随して生成し、均一に多孔質シート中に存在するので、微粒子を融解してなる多孔質シートは、均一で微細な孔を多数もつ微多孔シートとなる。本発明によって得られた多孔質シートは、フィルターや各種セパレータ、水を通さない衣類等の高機能多孔質シートとして使用される。 When the PFA fine particles of the present invention are melted, they function as an adhesive effect that joins the fine particles and the filaments or between the fine particles, and contributes to an increase in the mechanical strength of the porous sheet. Conventionally, an adhesive is used for the purpose of strengthening the inter-filament bonding of the nonwoven fabric. However, the method of applying the adhesive later increases the cost, and the emulsion or the solvent-based adhesive has a drawback that a film is stretched over the entire porous sheet and air permeability is impaired. Further, in the case of a powder-based adhesive, the fine-powder adhesive does not exist in the fluorine-based adhesive, and even if it exists, the cost is high, and it is difficult to uniformly adhere this powder adhesive to the porous sheet. On the other hand, since the PFA fine particles of the present invention are inherently generated in the porous sheet and are uniformly present in the porous sheet, the porous sheet obtained by melting the fine particles is uniform and fine. It becomes a microporous sheet having many holes. The porous sheet obtained by the present invention is used as a highly functional porous sheet such as a filter, various separators, and water-impervious clothing.
　従来のナノファイバーの生産方式であるＥＳ法は、ポリマーを溶剤に溶かす作業や出来た製品から脱溶剤をする必要があり、製造法において煩雑であり、コストアップである。また出来た製品も、ダマやショットと呼ばれる樹脂の固まりが生じること、フィラメント径の分布が広いなど、フィラメントの品質的にも問題であった。また出来たファイバーも、ショートファイバー（短繊維）で、長さ数ｍｍからせいぜい数１０ｍｍと云われている。また、本発明のＰＦＡポリマーに対しては有効な溶剤がないので、ＰＦＡのマイクロファイバーからなる不織布には適用不可能である。このように他の手段では製造が困難であるので、本発明のＰＦＡ多孔質シートは、非常に有益な機能性シートとなる。 The ES method, which is a conventional nanofiber production method, requires the solvent to be removed from the work of dissolving the polymer in the solvent or the finished product, which is complicated in the manufacturing method and increases the cost. In addition, the finished product also had problems with the quality of the filament, such as the occurrence of a mass of resin called lumps and shots, and a wide distribution of filament diameters. The resulting fiber is also a short fiber (short fiber), which is said to be several millimeters in length to several tens of millimeters at most. Further, since there is no effective solvent for the PFA polymer of the present invention, it cannot be applied to a nonwoven fabric made of PFA microfibers. Thus, since it is difficult to produce by other means, the PFA porous sheet of the present invention is a very useful functional sheet.
　本発明は、特殊で高精度・高レベルな装置を必要とせずに、簡便な手段で容易に分子配向が向上したＰＦＡ極細フィラメントが得られる。本発明では、延伸されたフィラメントを直接巻取機に巻き取って多孔質シートとすることができることも特徴とする。また本発明においては、ＰＦＡフィラメントは、１０，０００倍以上の延伸倍率を可能にし、１μｍ未満のナノフィラメントの領域に至る超極細のフィラメントを製造できた。また、出来たフィラメント径の分布も、ナノフィラメント域の平均フィラメント径であるにもかかわらず、標準偏差が０．５以下と非常に狭い極細フィラメントを得ることができた。 The present invention can obtain a PFA ultrafine filament with improved molecular orientation easily by a simple means without requiring a special, high precision and high level apparatus. The present invention is also characterized in that a stretched filament can be directly wound on a winder to form a porous sheet. Further, in the present invention, the PFA filament can be drawn at a magnification of 10,000 times or more, and an ultrafine filament reaching a nanofilament region of less than 1 μm can be produced. In addition, even though the distribution of the filament diameter was the average filament diameter in the nanofilament region, it was possible to obtain a very narrow filament with a standard deviation of 0.5 or less.
　本発明における炭酸ガスレーザービームによる超延伸法では、延伸張力が与えられる高速気体流の発生手段として、オリフィス前後における圧力差を利用する。そのために高速気体流の流れが非常に安定し、それによって、単にナノフィラメントが得られるばかりでなく、生産性においても安定した連続運転を可能にした。本発明では、多錘の原フィラメントを、簡便な手段で安定して延伸できる手段を提供することができた。レーザービームは、高価であるので、多数のビームを用意することはコストアップであるばかりでなく、レーザービームは、安全性の面でも、また、振動等の外的刺激に非常に敏感な超精密機器を用いることより、多数セットのレーザー発振装置を用いることは得策ではない。本発明においては、一つの炭酸ガスレーザービームより、多錘の原フィラメントの延伸を可能にしたことに特徴がある。さらに本発明は、閉鎖系の密閉室で行うことができるので、開放系で行うメルトブロー法やＥＳ法に比べ、得られたナノファイバーの大気中への飛散を防ぐことができ、作業環境の安全性が高い。 In the super-stretching method using a carbon dioxide laser beam in the present invention, a pressure difference before and after the orifice is used as means for generating a high-speed gas flow to which stretching tension is applied. For this reason, the flow of the high-speed gas flow is very stable, which not only provides nanofilaments but also enables stable continuous operation in terms of productivity. In the present invention, it was possible to provide a means for stably stretching a multifilamentary original filament by a simple means. Since laser beams are expensive, it is not only costly to prepare a large number of beams, but also the laser beam is ultra-precise in terms of safety and very sensitive to external stimuli such as vibration. It is not a good idea to use multiple sets of laser oscillators rather than using equipment. The present invention is characterized in that a plurality of original filaments can be drawn from one carbon dioxide laser beam. Furthermore, since the present invention can be performed in a closed closed chamber, compared to the melt blow method and ES method performed in an open system, the obtained nanofibers can be prevented from scattering into the atmosphere, and the working environment is safe. High nature.
本発明の多数のＰＦＡ微粒子を伴ったＰＦＡフィラメントからなる多孔質シートの電子顕微鏡写真（倍率１０，０００）。The electron micrograph (10,000 magnifications) of the porous sheet which consists of a PFA filament with many PFA microparticles | fine-particles of this invention. 本発明のＰＦＡ微粒子が熱処理によって融解して、フィラメントや他の微粒子と融着している状態の電子顕微鏡写真（倍率１０，０００）。The electron micrograph of the state which the PFA microparticles | fine-particles of this invention melt | dissolved by heat processing, and are fuse | melted with the filament and other microparticles (magnification 10,000). 本発明の多数のＰＦＡ微粒子が２６０℃熱処理によって変化する態様を未処理と比較して示す電子顕微鏡写真（倍率、１、０００倍、５，０００倍、１０，０００倍）。The electron micrograph which shows the aspect which many PFA microparticles | fine-particles of this invention change by 260 degreeC heat processing compared with an unprocessed (magnification | multiplication, 1,000 times, 5,000 times, 10,000 times). 本発明の多数のＰＦＡ微粒子が２７０℃熱処理によって変化する態様を未処理と比較して示す電子顕微鏡写真（倍率、１、０００倍、５，０００倍、１０，０００倍）。The electron micrograph which shows the aspect which many PFA microparticles | fine-particles of this invention change by 270 degreeC heat processing compared with an unprocessed (magnification | multiplication, 1,000 times, 5,000 times, 10,000 times). 本発明の多数のＰＦＡ微粒子が２８０℃熱処理によって変化する態様を未処理と比較して示す電子顕微鏡写真（倍率、１、０００倍、５，０００倍、１０，０００倍）。The electron micrograph which shows the aspect which many PFA microparticles | fine-particles of this invention change by 280 degreeC heat processing compared with an unprocessed (magnification | multiplication, 1,000 times, 5,000 times, 10,000 times). 本発明の多数のＰＦＡ微粒子が３００℃熱処理によって変化する態様を示すシートの外観写真と電子顕微鏡写真（倍率、１０，０００倍）。The external appearance photograph and electron micrograph (magnification | multiplication of 10,000 times) of the sheet | seat which show the aspect which many PFA microparticles | fine-particles of this invention change by 300 degreeC heat processing. 本発明のＰＦＡフィラメントの多錘延伸によってＰＦＡ多孔質シートを製造する原理を示す概念図。The conceptual diagram which shows the principle which manufactures a PFA porous sheet by the multi-cylinder drawing of the PFA filament of this invention. 本発明のレーザービームと多錘のオリフィスとの相対的関係を示す概念図。The conceptual diagram which shows the relative relationship between the laser beam of this invention, and the orifice of a multiple spindle. 図８の装置で多錘の原ＰＦＡフィラメントを延伸して得られたＰＦＡ多孔質シートを、電子顕微鏡写真（倍率１０，０００）と、その場合の繊維径分布。FIG. 8 is an electron micrograph (magnification 10,000) of a PFA porous sheet obtained by stretching a plurality of original PFA filaments with the apparatus of FIG. 8 and a fiber diameter distribution in that case. 本発明における原フィラメント供給室が気圧Ｐ１の部屋で、延伸室がＰ２気圧である部屋である場合の例を示す装置の断面図。Sectional drawing of the apparatus which shows an example in case the original filament supply chamber in this invention is a room | chamber with the atmospheric pressure P1, and a extending | stretching chamber is a room | chamber with P2 atmospheric pressure. 本発明の多錘延伸によって得られたＰＦＡ極細フィラメントを巻取装置に直接集積する例を示す概念図。The conceptual diagram which shows the example which integrates | stacks directly on the winding apparatus the PFA ultrafine filament obtained by the multi-cylinder drawing of this invention.
　以下、本発明の実施の形態の例を、図面に基づいて説明する。図１は、本発明の多数のＰＦＡ微粒子を伴ったＰＦＡフィラメントからなる多孔質シートを電子顕微鏡写真（倍率１０，０００）で示す。図の多数のフィラメントは、０．０３０ｍ／分で走行するコンベアネット上に集積された延伸されたＰＦＡ多孔質シートを示す。図の寸法表示より２００ｎｍから８００ｎｍで、全てのフィラメントが１０μｍ以下である。また、図のそれぞれのフィラメントには多数の微粒子が付着して観察され、その粒子は球形で、径は１００ｎｍ以下であり、全ては観察されるフィラメント径より小さい。この微粒子のみを集めて、ＧＰＣ測定やＤＳＣ測定を行ったが、フィラメントを含む多孔質シートのそれらの結果と差異は見いだせなかった。この図の多孔質シートは、ＰＦＡ原フィラメントが１００μｍで、図７の延伸装置で１５錘延伸した。その際のオリフィス径は、０．５ｍｍである。この時のレーザー発振装置は、（株）鬼塚硝子社製の炭酸ガスレーザー発振装置であり、出力４０Ｗで使用した。その際のレーザービーム径は、２．４ｍｍである。この原フィラメントの送出速度０．１ｍ／ｍｉｎで送り出した。延伸室の真空度は、５４ｋＰａで、エアーの流速は１００ｍ／ｓｅｃである。 Hereinafter, examples of embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an electron micrograph (magnification 10,000) of a porous sheet composed of PFA filaments with a large number of PFA fine particles of the present invention. The numerous filaments in the figure show the stretched PFA porous sheet accumulated on a conveyor net running at 0.030 m / min. All filaments are 10 μm or less from 200 nm to 800 nm from the dimensional display in the figure. In addition, a large number of fine particles adhere to each filament in the figure and are observed. The particles are spherical and have a diameter of 100 nm or less, all of which are smaller than the observed filament diameter. Only these fine particles were collected and subjected to GPC measurement and DSC measurement, but no difference was found from those results of the porous sheet containing the filament. The porous sheet of this figure had a PFA raw filament of 100 μm and was stretched by 15 spindles with the stretching apparatus of FIG. The orifice diameter at that time is 0.5 mm. The laser oscillation device at this time was a carbon dioxide laser oscillation device manufactured by Onitsuka Glass Co., Ltd., and was used at an output of 40 W. The laser beam diameter at that time is 2.4 mm. The original filament was sent out at a delivery speed of 0.1 m / min. The degree of vacuum in the stretching chamber is 54 kPa, and the air flow rate is 100 m / sec.
　図２は、図1のＰＦＡ多孔質シートを、３００℃で１分間熱処理した場合の電子顕微鏡写真（倍率１０，０００倍）を示す。熱処理により、フィラメント同士、フィラメントと微粒子、微粒子相互間が融着していることがわかる。 FIG. 2 shows an electron micrograph (magnification 10,000 times) when the PFA porous sheet of FIG. 1 is heat-treated at 300 ° C. for 1 minute. It can be seen that the filaments, the filaments and the fine particles, and the fine particles are fused together by the heat treatment.
　図３－５は、下記に示す条件で製作したＰＦＡ多孔質シートを、熱風空間中で、種々の温度で熱処理した場合を未処理と比較して電子顕微鏡写真（倍率、１、０００倍、５，０００倍、１０，０００倍）で比較して示す。この場合の未処理のＰＦＡ多孔質シートは、径が１００μｍの原ＰＦＡフィラメントを使用し、オリフィス径０．５ｍｍ、レーザー出力３０Ｗで延伸して、１０分間集積して得られたシートである。延伸室の真空度は、０．０５４ＭＰａ（風速３００ｍ／ｓｅｃ）で行った。図３は、２６０℃で時間を変えて熱処理した場合を、電子顕微鏡倍率を変えて示してある。図３では、微粒子の融解が明確ではない。図４は２７０℃の場合で、３０分で微粒子の融解が始まり、６０分で微粒子間が融着していることがわかる。図５は２８０℃の場合で、３０分以下で微粒子の融解が始まり、微粒子間が融着しており、６０分ではフィラメント間で融着が始まっている。 FIG. 3-5 is an electron micrograph (magnification, 1,000 times, 5 times) of a PFA porous sheet manufactured under the conditions shown below when heat treated at various temperatures in a hot air space as compared to untreated. , 10,000 times, 10,000 times). The untreated PFA porous sheet in this case is a sheet obtained by using an original PFA filament with a diameter of 100 μm, stretching with an orifice diameter of 0.5 mm and a laser output of 30 W, and accumulating for 10 minutes. The degree of vacuum in the stretching chamber was 0.054 MPa (wind speed 300 m / sec). FIG. 3 shows the case where heat treatment is performed at 260 ° C. for different times while the electron microscope magnification is changed. In FIG. 3, the melting of the fine particles is not clear. FIG. 4 shows the case of 270 ° C., where the melting of the fine particles starts in 30 minutes and the fine particles are fused in 60 minutes. FIG. 5 shows the case of 280 ° C., melting of the fine particles started in 30 minutes or less, and the fine particles are fused, and in 60 minutes, the fusion between the filaments is started.
　図６は、図３－５で使用した未処理のＰＦＡ多孔質シートを、熱風空間中で、３００℃で熱処理した場合を、熱処理時間を変化させてシートの外観写真とシートの電子顕微鏡写真（倍率、１０，０００倍）で示す。1分以下で微粒子間の融着が始まり、２分ではフィラメント間の融着が始まっている。 FIG. 6 shows the appearance of the sheet and the electron micrograph of the sheet when the heat treatment time was changed when the untreated PFA porous sheet used in FIG. 3-5 was heat-treated at 300 ° C. in a hot air space. (Magnification, 10,000 times). In 1 minute or less, fusion between fine particles starts, and in 2 minutes, fusion between filaments begins.
　図７は、本発明の多錘延伸によってＰＦＡ極細フィラメントを製造する原理を示す概念図で、装置の斜視図で示す。ＰＦＡ原フィラメント１ａ、１ｂ、１ｃ、・・・は、リール２に巻かれた状態から繰り出され、コーム等（図では省略）を経て、繰出ニップローラ（図では省略）等により一定速度で送り出される。板３には、多数のオリフィス４ａ，４ｂ，４ｃ、・・・の孔が彫られており、送り出されてきたＰＦＡ原フィラメント１は、オリフィス４へと導かれる。この図におけるここまでの工程は、原フィラメント供給室の気圧Ｐ１が大気圧に保たれて、特別の部屋を必要としない場合について図示してある。オリフィス４ａ，４ｂ，４ｃ、・・・の出口以降は、Ｐ２気圧下（この図では負圧状態）にある延伸室１１となる。オリフィス４ａ，４ｂ，４ｃ、・・・を出た原フィラメント１ａ、１ｂ、１ｃ、・・・は、原フィラメント供給室と延伸室との気圧差Ｐ１－Ｐ２によってもたらされる高速エアーと共に延伸室１１に導かれる。炭酸ガスレーザー発振装置５より出たレーザービーム６が、オリフィス４ａ，４ｂ，４ｃ、・・・直下において、多錘（マルチ）の原フィラメント１ａ、１ｂ、１ｃ、・・・に対して照射される。なお、レーザービーム６を延伸室１１内へ導くには、Ｚｎ－Ｓｅからなる窓７を通過する。レーザービーム６により加熱され、Ｐ１－Ｐ２の気圧差によってもたらされる高速エアーが下方のフィラメントに与える張力により、原フィラメント１ａ、１ｂ、１ｃ、・・・は延伸されて、延伸されたフィラメント１２ａ、１２ｂ、１２ｃ、・・・となって下降する。延伸室１１の下方には、同じＰ２圧力でつながっている空間であるフィラメント集積室１３があり、コンベア１４が循環している。このコンベア１４上に延伸室１１で延伸されたフィラメント１２ａ、１２ｂ、１２ｃ、・・・が集積される。気圧Ｐ２は、バルブ１５を通じて真空ポンプ（図示されていない）へ導かれている。真空度は、調整するバルブ１５、および真空ポンプの回転数、バイパスバルブ等で調整される。図において、コンベア１４上に集積されたウェブは、多数の微粒子を伴っており、本発明の多孔質シート１６となる。この多孔質シート１６を熱風中熱処理処理することにより熱処理された多孔質シートとなる。 FIG. 7 is a conceptual view showing the principle of manufacturing a PFA ultrafine filament by multi-spindle drawing of the present invention, and is a perspective view of the apparatus. The PFA original filaments 1a, 1b, 1c,... Are fed out from the state wound around the reel 2, and are fed at a constant speed by a feeding nip roller (omitted in the drawing) through a comb or the like (omitted in the drawing). A large number of orifices 4 a, 4 b, 4 c,... Are carved in the plate 3, and the PFA raw filament 1 sent out is guided to the orifice 4. The steps up to this point in this figure are shown in the case where the pressure P1 of the original filament supply chamber is maintained at atmospheric pressure and no special room is required. After the outlets of the orifices 4a, 4b, 4c,..., The extension chamber 11 is under P2 atmospheric pressure (negative pressure in this figure). The original filaments 1a, 1b, 1c,... Exiting the orifices 4a, 4b, 4c,... Enter the drawing chamber 11 together with high-speed air brought about by the pressure difference P1-P2 between the original filament supply chamber and the drawing chamber. Led. A laser beam 6 emitted from the carbon dioxide laser oscillation device 5 is irradiated on the original filaments 1a, 1b, 1c,... Of a multi-piece (multi) just below the orifices 4a, 4b, 4c,. . In order to guide the laser beam 6 into the stretching chamber 11, it passes through a window 7 made of Zn—Se. The original filaments 1a, 1b, 1c,... Are stretched by the tension applied to the lower filaments by the high-speed air heated by the laser beam 6 and caused by the pressure difference P1-P2, and the drawn filaments 12a, 12b are stretched. , 12c,. Below the stretching chamber 11, there is a filament accumulation chamber 13, which is a space connected by the same P2 pressure, and a conveyor 14 circulates. Filaments 12 a, 12 b, 12 c,... Stretched in the stretching chamber 11 are accumulated on the conveyor 14. The atmospheric pressure P2 is led through a valve 15 to a vacuum pump (not shown). The degree of vacuum is adjusted by the valve 15 to be adjusted, the number of rotations of the vacuum pump, a bypass valve, and the like. In the figure, the web accumulated on the conveyor 14 is accompanied by a large number of fine particles, and becomes the porous sheet 16 of the present invention. A heat-treated porous sheet is obtained by heat-treating the porous sheet 16 in hot air.
なお図７において、延伸室１１とそれと一体化しているフィラメント集積室１３は、位置微調整架台１７、１８、１９上に設けられており、レーザービーム６の照射範囲の中にオリフィス４ａ，４ｂ，４ｃ、・・・を出たＰＦＡ原フィラメントａ、１ｂ、１ｃ、・・・が最適に収まるように位置を微調整する。一番下の位置微調整架台１８は上下（Ｚ軸）方向に調整し、中の位置微調整架台１９は横（Ｘ軸又はＹ軸）方向調整し、一番上の位置微調整架台２０はターンテーブルになっており、回転させて位置を微調整する。 In FIG. 7, the stretching chamber 11 and the filament accumulation chamber 13 integrated with the stretching chamber 11 are provided on the position fine adjustment bases 17, 18, 19, and the orifices 4 a, 4 b, 4c,... Are finely adjusted so that the PFA original filaments a, 1b, 1c,. The bottom position fine adjustment base 18 is adjusted in the vertical (Z axis) direction, the middle position fine adjustment base 19 is adjusted in the lateral (X axis or Y axis) direction, and the top position fine adjustment base 20 is It is a turntable that is rotated to fine-tune the position.
図８は、本発明のレーザービームと多錘のオリフィスとの相対的関係を概念図で示す。ターンテーブルからなる微調整架台１９上に載っているフィラメント集積室１３ａ（延伸室１１は、フィラメント集積室１３と一体化している）は、ターンテーブルを角度Θだけ回転して位置を微調整して、レーザービーム６の照射範囲にオリフィス４ａ、４ｂ、４ｃ、・・・の中を走るＰＦＡ原フィラメント（図では省略）が収まる位置を探して、最適な位置のフィラメント集積室１３ｂとする。このように、角度Θを微調整することにより、より多錘の原フィラメントの延伸の最適位置を求める。 FIG. 8 is a conceptual diagram showing the relative relationship between the laser beam of the present invention and the orifice of a multi-cage. The filament accumulation chamber 13a (the drawing chamber 11 is integrated with the filament accumulation chamber 13) mounted on the fine adjustment frame 19 made of a turntable is rotated by an angle Θ to finely adjust the position. The position where the PFA original filament (not shown in the figure) running through the orifices 4a, 4b, 4c,... Fits within the irradiation range of the laser beam 6 is searched for, and the filament accumulation chamber 13b is set to the optimum position. In this way, by adjusting the angle Θ finely, the optimum position for stretching the multifilamentary original filament is obtained.
　図９は、図８の装置を使用して、フィラメント径１００μｍの原ＰＦＡフィラメント１７錘で実験した場合で、得られたシートの左、中央、右の部分の電子顕微鏡写真（倍率１０、０００倍）と、その得られたフィラメントのフィラメント径の分布を示した。図８における回転角度は、Θ＝０度３５分である。原フィラメント供給速度０．５ｍ／ｍｉｎ、オリフィス径０．５ｍｍ（エアー流速２８０ｍ／ｓｅｃ）で、図７のコンベア上に集積した。得られたフィラメントは、平均フィラメント径が約５００－６００ｎｍのナノフィラメントであり、標準偏差が０．２３－０．４６で、フィラメント径も良く揃っていることがわかる。 FIG. 9 shows an electron micrograph (magnification 10,000 times) of the left, center, and right portions of the obtained sheet when an experiment was performed with 17 spindles of an original PFA filament having a filament diameter of 100 μm using the apparatus of FIG. ) And the distribution of filament diameters of the obtained filaments. The rotation angle in FIG. 8 is Θ = 0 degrees 35 minutes. The raw filament supply speed was 0.5 m / min and the orifice diameter was 0.5 mm (air flow rate 280 m / sec). The obtained filaments are nanofilaments having an average filament diameter of about 500-600 nm, a standard deviation of 0.23-0.46, and it can be seen that the filament diameters are well aligned.
　図１０は、原フィラメント供給室２１が気圧Ｐ１の部屋で、延伸室２２がＰ２気圧である部屋である場合の例を示す装置の断面図である。原フィラメント供給室２１のＰ１気圧は、バルブ２３と配管２４を経てコンプレッサー（又は真空ポンプ）へ通じている。Ｐ１気圧は、気圧計２５により管理されている。延伸室２２のＰ２気圧は、バルブ２６と配管２７を経て真空ポンプ（又はコンプレッサー）へ通じている。Ｐ２気圧は、気圧計２８により管理されている。ＰＦＡ原フィラメント１ａ、１ｂ、１ｃは、リール２９ａ、２９ｂ、２９ｃに巻かれた状態から繰り出され、コーム３０ａ、３０ｂ、３０ｃを経て、繰出ニップローラ３１ａ、３２ａ、３１ｂ、３２ｂ、３１ｃ、３２ｃより一定速度で送り出され、オリフィス３３ａ、３３ｂ、３３ｃ、・・・へと導かれる。  FIG. 10 is a cross-sectional view of an apparatus showing an example in which the original filament supply chamber 21 is a room having an atmospheric pressure P1 and the stretching chamber 22 is a room having a P2 atmospheric pressure. The P1 atmospheric pressure in the original filament supply chamber 21 is communicated with a compressor (or a vacuum pump) through a valve 23 and a pipe 24. The P1 atmospheric pressure is managed by the barometer 25. The P2 atmospheric pressure in the stretching chamber 22 communicates with a vacuum pump (or a compressor) through a valve 26 and a pipe 27. The P2 atmospheric pressure is managed by the barometer 28. The PFA original filaments 1a, 1b and 1c are fed out from the state wound around the reels 29a, 29b and 29c, and are fed at constant speed from the feeding nip rollers 31a, 32a, 31b, 32b, 31c and 32c via the combs 30a, 30b and 30c. And are led to the orifices 33a, 33b, 33c,.
　図１０のオリフィス３３ａ、３３ｂ、３３ｃの出口以降は、Ｐ２気圧下にある延伸室２２となる。オリフィス３３ａ、３３ｂ、３３ｃを出たＰＦＡ原フィラメント１ａ、１ｂ、１ｃは、原フィラメント供給室２１と延伸室２２との気圧差Ｐ１－Ｐ２によってもたらされる高速エアーと共に延伸室２２に導かれる。送り出されたＰＦＡ原フィラメント１ａ、１ｂ、１ｃは、オリフィス直下において、炭酸ガスレーザー発振装置５より照射されたレーザービーム６は、走行する原フィラメント１ａ、１ｂ、１ｃに対して照射される。レーザービーム６の届く先には、レーザービームのパワーメータ３４が設けれ、レーザーパワーを一定に調節されていることが好ましい。レーザービーム６により加熱され、Ｐ１－Ｐ２の気圧差によってもたらされる高速エアーが下方のフィラメントに与える張力により、原フィラメント１ａ、１ｂ、１ｃは延伸されて、延伸されたフィラメント３５ａ、３５ｂ、３５ｃとなって下降し、コンベア１４上に集積されて、多数のＰＦＡ微粒子を含むＰＦＡ多孔質シート３６となる。  10 and the outlets of the orifices 33a, 33b, and 33c in FIG. The PFA original filaments 1a, 1b, and 1c that have exited the orifices 33a, 33b, and 33c are guided to the drawing chamber 22 together with high-speed air caused by the pressure difference P1-P2 between the original filament supply chamber 21 and the drawing chamber 22. The fed PFA original filaments 1a, 1b, and 1c are irradiated directly on the traveling original filaments 1a, 1b, and 1c with the laser beam 6 irradiated from the carbon dioxide laser oscillation device 5 immediately below the orifice. A laser beam power meter 34 is preferably provided at the destination of the laser beam 6, and the laser power is preferably adjusted to be constant. The original filaments 1a, 1b, and 1c are drawn by the tension applied to the lower filament by the high-speed air that is heated by the laser beam 6 and brought about by the pressure difference of P1-P2, and becomes the drawn filaments 35a, 35b, and 35c. And is accumulated on the conveyor 14 to become a PFA porous sheet 36 containing a large number of PFA fine particles.
　図１０において、コンベア１４の裏からは、負圧吸引室３７によって吸引されて、コンベア１４上のＰＦＡ多孔質シート３６を安定化させることが好ましい。ＰＦＡ多孔質シート３６は、下記の熱処理手段の少なくとも一つにより熱処理されることが好ましい。熱処理手段の１は、赤外線ランプ３８による輻射熱で、ＰＦＡ多孔質シート３６が加熱され、熱処理される。熱処理手段の２は、熱風ノズル３９より噴出する熱風によりＰＦＡ多孔質シート３６が加熱され、熱処理される。コンベア１４を出る多孔質シート３６は、コンベア１４上でゴムロール４０により圧縮され、シート化されることが好ましい。熱処理手段の３は、コンベア１４を出たＰＦＡ多孔質シート３６は加熱ロール４１により熱処理され、ゴムロール４２により圧縮され、シート化される。熱処理されたＰＦＡ多孔質シート４３は巻取ロール４４に巻き取られる。  In FIG. 10, it is preferable that the PFA porous sheet 36 on the conveyor 14 is stabilized by being sucked by the negative pressure suction chamber 37 from the back of the conveyor 14. The PFA porous sheet 36 is preferably heat treated by at least one of the following heat treatment means. One of the heat treatment means is radiant heat from the infrared lamp 38, and the PFA porous sheet 36 is heated and heat-treated. In the heat treatment means 2, the PFA porous sheet 36 is heated by the hot air blown from the hot air nozzle 39 to be heat-treated. The porous sheet 36 exiting the conveyor 14 is preferably compressed by the rubber roll 40 on the conveyor 14 and formed into a sheet. In the heat treatment means 3, the PFA porous sheet 36 exiting the conveyor 14 is heat treated by a heating roll 41, compressed by a rubber roll 42, and formed into a sheet. The heat-treated PFA porous sheet 43 is wound around a winding roll 44.
　図１１は、本発明のフィラメント集積装置として巻取機を用いた場合において、延伸室内に捕集ガイドを設けた場合の例を示す。図７と同様な装置で、板状物５１に多数の孔が開けられ、それらの孔をそれぞれオリフィス５２ａ、５２ｂ、５２ｃとし、多数のＰＦＡ原フィラメント１ａ、１ｂ、１ｃ、・・・が、これらのオリフィス５２を通じてＰ２気圧下（この図では負圧状態）にある延伸室５３へと導かれている。炭酸ガスレーザー発振装置５より出たレーザービーム６は、オリフィス５２直下において、多錘（マルチ）の原フィラメント１ａ、１ｂ、１ｃ、・・・に対して照射される。なお、レーザービーム６を延伸室５３内へ導くには、Ｚｎ－Ｓｅからなる窓を通過するが、その窓は図では省略してある。レーザービーム６により加熱され、Ｐ１－Ｐ２の気圧差によってもたらされる高速エアーが下方のフィラメントに与える張力により、原フィラメント１ａ、１ｂ、１ｃ、・・・は延伸されて、延伸されたフィラメント１２ａ、１２ｂ、１２ｃ、・・・となって下降し、下方の巻取装置５４へ直接巻き取られる。巻取装置５４は、巻取架台５５に設置された巻取管５６からなり、巻取管がモータにより駆動（図示されていない）されて回転し、この巻取管５６上に延伸されたフィラメント１２は巻き付けられ、集積されて、延伸されたフィラメント集積体が多数の微粒子を含むＰＦＡ多孔質シート５７となる。この延伸室５３には、巻取管１１３に沿って湾曲している捕集ガイド５８が設けられていることを特徴とする。この捕集ガイド５８により、ＰＦＡ多孔質シート５７は、安定して巻取管５６に巻かれ、地合の良いＰＦＡ多孔質シート５７となる。 FIG. 11 shows an example in which a collection guide is provided in the drawing chamber when a winder is used as the filament accumulating device of the present invention. 7, a large number of holes are made in the plate-like object 51, and these holes are respectively orifices 52 a, 52 b, 52 c, and a large number of PFA original filaments 1 a, 1 b, 1 c,. The orifice 52 is led to the stretching chamber 53 under P2 atmospheric pressure (in this figure, a negative pressure state). The laser beam 6 emitted from the carbon dioxide laser oscillation device 5 is irradiated on the original filaments 1a, 1b, 1c,. In order to guide the laser beam 6 into the stretching chamber 53, it passes through a window made of Zn—Se, but this window is omitted in the drawing. The original filaments 1a, 1b, 1c,... Are stretched by the tension applied to the lower filaments by the high-speed air heated by the laser beam 6 and caused by the pressure difference P1-P2, and the drawn filaments 12a, 12b are stretched. 12c,..., 12c,..., 12c,. The winding device 54 includes a winding tube 56 installed on a winding stand 55, and the winding tube is driven by a motor (not shown) to rotate, and the filament stretched on the winding tube 56. 12 is wound, accumulated, and the drawn filament aggregate becomes a PFA porous sheet 57 containing a large number of fine particles. The extending chamber 53 is provided with a collection guide 58 that is curved along the winding tube 113. By this collection guide 58, the PFA porous sheet 57 is stably wound around the take-up tube 56 and becomes a PFA porous sheet 57 with good formation.
　本発明は、微粒子を伴うＰＦＡフィラメントからなるＰＦＡ多孔質シートに関し、フィルター、セパレータ、水を通さない衣類等に使用される。 The present invention relates to a PFA porous sheet composed of PFA filaments with fine particles, and is used for filters, separators, water-impervious clothing, and the like.
１：ＰＦＡ原フィラメント、　２：リール、　３：板、　４：オリフィス、
５：炭酸ガスレーザー発振装置、　６：レーザービーム、　７：Ｚｎ－Ｓｅ窓、
１１：延伸室、　１２：延伸されたフィラメント、　１３：フィラメント集積室、
１４：コンベア、　１５：バルブ、　１６：ＰＦＡ多孔質シート、
１７、１８、１９：位置微調整架台。
２１：原フィラメント供給室、　２２：延伸室、　２３バルブ、　２４：配管、
２５：気圧計、　２６：バルブ、　２７：配管、　２８：気圧計、
２９：リール、　３０：コーム、　３１、３２：繰出ニップロール、
３３：オリフィス、　３４：パワーメータ、　３５：延伸されたフィラメント、
３６：ＰＦＡ多孔質シート、　３７：負圧吸引室、　３８：赤外線ランプ、
３９：熱風ノズル、　４０：ゴムロール、　４１：加熱ロール、
４２：ゴムロール、　４３：熱処理されたウェブ、　４４：巻取ロール。
５１：板状物、　５２：オリフィス、　５３：延伸室、　５４：巻取装置、
５５：巻取架台、　５６：巻取管、　５７：ＰＦＡ多孔質シート、
５８：捕集ガイド。 1: PFA raw filament, 2: reel, 3: plate, 4: orifice,
5: Carbon dioxide laser oscillation device, 6: Laser beam, 7: Zn-Se window,
11: Stretching chamber, 12: Stretched filament, 13: Filament accumulation chamber,
14: Conveyor, 15: Valve, 16: PFA porous sheet,
17, 18, 19: Position fine adjustment mount.
21: Raw filament supply chamber, 22: Stretch chamber, 23 valve, 24: Piping,
25: Barometer, 26: Valve, 27: Piping, 28: Barometer
29: Reel, 30: Comb, 31, 32: Feeding nip roll,
33: Orifice, 34: Power meter, 35: Stretched filament,
36: PFA porous sheet, 37: negative pressure suction chamber, 38: infrared lamp,
39: Hot air nozzle, 40: Rubber roll, 41: Heating roll,
42: Rubber roll, 43: Heat treated web, 44: Winding roll.
51: plate-like material, 52: orifice, 53: stretching chamber, 54: winding device,
55: Winding stand 56: Winding tube 57: PFA porous sheet
58: Collection guide.

Claims (11)

  1. 　平均フィラメント径が１０μｍ以下のＰＦＡ（テトラフルオロエチレン・パーフルオロアルキルビニルエーテル共重合体）からなるフィラメント群と、個々の該フィラメントが、該平均フィラメント径以下のＰＦＡ微粒子を多数含むことを特徴とする、ＰＦＡ多孔質シート。 A filament group composed of PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) having an average filament diameter of 10 μm or less, and each of the filaments contains a large number of PFA fine particles having an average filament diameter of less than PFA porous sheet.
  2. 　前記ＰＦＡフィラメントが１μｍ未満の平均フィラメント径を有することを特徴とする、請求項１に記載されたＰＦＡ多孔質シート。 The PFA porous sheet according to claim 1, wherein the PFA filament has an average filament diameter of less than 1 μm.
  3. 　前記微粒子が融解されており、該微粒子と前記フィラメント、および該微粒子相互間が融着されていることを特徴とする、請求項１に記載されたＰＦＡ多孔質シート。 The PFA porous sheet according to claim 1, wherein the fine particles are melted, and the fine particles, the filaments, and the fine particles are fused to each other.
  4. 　多錘のＰＦＡ（テトラフルオロエチレン・パーフルオロアルキルビニルエーテル共重合体）原フィラメントがＰ１気圧下において送出手段によって送り出されて行く工程と、
    該原フィラメント群がオリフィス中を通過して、Ｐ２気圧下（Ｐ１＞Ｐ２）の延伸室へ導かれる工程と、
    該延伸室において、該オリフィスを通過してきた該原フィラメント群が、炭酸ガスレーザービームを照射されることによって加熱され、Ｐ１からＰ２の気圧差によって生ずる該オリフィスからの気体の流れによって生ずる牽引力によって延伸される工程と、
    延伸されたフィラメント群を集積する工程と、
    を有することによって平均フィラメント径が１０μｍ以下のＰＦＡフィラメント群と平均フィラメント径以下のＰＦＡ微粒子を多数含むシートにされることを特徴とする、ＰＦＡ多孔質シートの製造方法。　     A process in which a multi-filamentary PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) raw filament is sent out by a feeding means under P1 atmosphere;
    A step of passing the original filament group through the orifice and being led to a drawing chamber under P2 atmospheric pressure (P1>P2);
    In the stretching chamber, the original filament group that has passed through the orifice is heated by being irradiated with a carbon dioxide laser beam, and is stretched by a traction force generated by a gas flow from the orifice caused by a pressure difference between P1 and P2. A process to be performed;
    Collecting the drawn filaments; and
    A method for producing a PFA porous sheet, comprising a PFA filament group having an average filament diameter of 10 μm or less and a PFA fine particle having an average filament diameter of 10 μm or less.
  5. 　前記Ｐ１が大気圧であり、前記Ｐ２が減圧下であることを特徴とする、請求項４記載のＰＦＡ多孔質シートの製造方法。 The method for producing a PFA porous sheet according to claim 4, wherein P1 is atmospheric pressure and P2 is under reduced pressure.
  6. 　前記オリフィスを出た多錘の原ＰＦＡフィラメント群が、延伸室全体を回転させることによってレーザービームが均一に当たる個所を探された後に、延伸を始められることを特徴とする、請求項４記載のＰＦＡ多孔質シートの製造方法。 5. The PFA according to claim 4, wherein a plurality of original PFA filament groups exiting the orifice are started to be stretched after a portion where the laser beam uniformly hits is searched by rotating the entire stretching chamber. A method for producing a porous sheet.
  7. 　前記炭酸ガスレーザービームの中心が、前記オリフィスの出口より３０ｍｍ以内で前記原フィラメントに照射されることを特徴とする、請求項４記載のＰＦＡ多孔質シートの製造方法。 The method for producing a PFA porous sheet according to claim 4, wherein the original filament is irradiated within 30 mm from the outlet of the orifice at the center of the carbon dioxide laser beam.
  8. 　前記炭酸ガスレーザービームビームが、前記原フィラメントの中心でフィラメントの軸方向に沿って上下４ｍｍ以内の範囲に照射されることを特徴とする、請求項４記載のＰＦＡ多孔質シートの製造方法。 The method for producing a PFA porous sheet according to claim 4, wherein the carbon dioxide laser beam is irradiated within a range of up to 4 mm along the axial direction of the filament at the center of the original filament.
  9. 前記延伸されたフィラメント群と多数の微粒子の集積が前記延伸室内で走行しているコンベアによって行われることを特徴とする、請求項４記載のＰＦＡ多孔質シートの製造方法。 The method for producing a PFA porous sheet according to claim 4, wherein the stretched filament group and a large number of fine particles are accumulated by a conveyor running in the stretching chamber.
  10. 前記延伸されたフィラメント群と多数の微粒子の集積が、前記延伸室内の巻取機の回転軸を中心に巻き取られ、該回転軸の外側に、該延伸されたフィラメント群が降下してくる巾に対応した巾を持ち、該回転軸に沿って湾曲している壁を有する捕集ガイドによってフィラメント群等を有効に回転軸に巻きつけるのを補助することを特徴とする、請求項４記載のＰＦＡ多孔質シートの製造方法。 The stretched filament group and the collection of a large number of fine particles are wound around the rotating shaft of the winder in the stretching chamber, and the width of the stretched filament group descends outside the rotating shaft. 5. The filament guide or the like is effectively wound around the rotating shaft by a collection guide having a wall corresponding to the above and having a wall curved along the rotating shaft. A method for producing a PFA porous sheet.
  11. 前記微粒子を含む前記多孔質シートが、２７０℃以上で熱処理されることにより、該微粒子が融解して、該微粒子と該フィラメント、および該微粒子相互間が融着されることを特徴とする、請求項４記載のＰＦＡ多孔質シートの製造方法。 The porous sheet containing the fine particles is heat-treated at 270 ° C. or higher, whereby the fine particles are melted, and the fine particles, the filaments, and the fine particles are fused to each other. Item 5. A method for producing a PFA porous sheet according to Item 4.
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JP5938730B2 (en) * 2011-02-25 2016-06-22 国立大学法人山梨大学 Sheet made of different filaments and means for producing the same

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