WO2011105414A1 - Feuille poreuse en pfa - Google Patents

Feuille poreuse en pfa 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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Prior art keywords
filament
pfa
porous sheet
fine particles
filaments
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PCT/JP2011/053944
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English (en)
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/zh
Publication of WO2011105414A1 publication Critical patent/WO2011105414A1/fr

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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.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Nonwoven Fabrics (AREA)
  • Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)

Abstract

L'invention concerne une feuille poreuse en PFA (copolymère de tétrafluoroéthylène-éther de vinyle perfluoré) comportant des filaments de PFA et présentant une résistance accrue à la traction et une surface spécifique accrue. La feuille poreuse en PFA comporte des micro-filaments de PFA présentant un diamètre moyen de filament inférieur ou égal à 10 μm, et est caractérisée en ce que chacun des filaments contient de nombreuses microparticules de PFA de taille inférieure ou égale au diamètre moyen de filament. L'invention concerne également un moyen de production de la feuille poreuse en PFA.
PCT/JP2011/053944 2010-02-26 2011-02-23 Feuille poreuse en pfa WO2011105414A1 (fr)

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JP2010041228A JP2011179126A (ja) 2010-02-26 2010-02-26 Ｐｆａ多孔質シート

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JP5938730B2 (ja) * 2011-02-25 2016-06-22 国立大学法人山梨大学 異種フィラメントからなるシート及びその製造手段

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KR101298653B1 (ko) * 2012-05-11 2013-08-26 동아대학교 산학협력단 다중공 필라멘트사 및 그 제조방법과 이를 이용하여 제조한 물품
JP7392318B2 (ja) * 2019-08-08 2023-12-06 東レ株式会社 フッ素系繊維から成る抄紙
CN111321516B (zh) * 2020-04-02 2021-03-30 青岛科凯达橡塑有限公司 一种长效驻极pp非纺织布及其制备方法

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JP2004107851A (ja) * 2002-09-17 2004-04-08 Yamanashi Tlo:Kk 延伸されたフィラメントの製造方法およびその製造装置および高度に分子配向した極細フィラメント
WO2008084797A1 (fr) * 2007-01-09 2008-07-17 University Of Yamanashi Procédé de production et dispositif de production d'un filament ultra-fin

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JP3918987B2 (ja) * 2001-08-27 2007-05-23 株式会社山梨ティー・エル・オー 極細繊維、その製造方法及び製造装置

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JP2004107851A (ja) * 2002-09-17 2004-04-08 Yamanashi Tlo:Kk 延伸されたフィラメントの製造方法およびその製造装置および高度に分子配向した極細フィラメント
WO2008084797A1 (fr) * 2007-01-09 2008-07-17 University Of Yamanashi Procédé de production et dispositif de production d'un filament ultra-fin

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Publication number Priority date Publication date Assignee Title
JP5938730B2 (ja) * 2011-02-25 2016-06-22 国立大学法人山梨大学 異種フィラメントからなるシート及びその製造手段

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