WO2023008052A1 - Nonwoven production device and production method - Google Patents

Nonwoven production device and production method Download PDF

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Publication number
WO2023008052A1
WO2023008052A1 PCT/JP2022/025714 JP2022025714W WO2023008052A1 WO 2023008052 A1 WO2023008052 A1 WO 2023008052A1 JP 2022025714 W JP2022025714 W JP 2022025714W WO 2023008052 A1 WO2023008052 A1 WO 2023008052A1
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Prior art keywords
polymer
nonwoven fabric
wall surface
nozzle
lip
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PCT/JP2022/025714
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French (fr)
Japanese (ja)
Inventor
寺本祐
船越祥二
田村知樹
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東レ株式会社
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Application filed by 東レ株式会社 filed Critical 東レ株式会社
Priority to CN202280042289.6A priority Critical patent/CN117500963A/en
Priority to KR1020247000325A priority patent/KR20240035437A/en
Priority to JP2022542335A priority patent/JP7168135B1/en
Publication of WO2023008052A1 publication Critical patent/WO2023008052A1/en

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    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D4/00—Spinnerette packs; Cleaning thereof
    • D01D4/02—Spinnerettes
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/08—Melt spinning methods

Definitions

  • the present invention relates to an apparatus and method suitable for manufacturing nonwoven fabrics by the meltblowing method.
  • a high-speed, high-temperature air stream is blown onto the polymer extruded from the nozzle of the spinneret to pull and melt-bond the polymer to form a web, which is captured on a net conveyor.
  • a meltblowing method in which a nonwoven fabric is obtained by gathering is mentioned.
  • the die used in the melt blowing method includes a nozzle having a group of discharge holes arranged in a line in the width direction, and a pair of lips arranged on both sides of the nozzle so as to face each other with the group of discharge holes interposed therebetween. A gap is formed between the nozzle and the lip.
  • nonwoven fabric made of ultrafine fibers.
  • nonwoven fabrics have been used in a wide variety of applications, and nonwoven fabrics with very small fiber diameters have been desired for high-performance applications such as filters, medical masks, and medical gowns.
  • the melt-blown nozzle disclosed in Patent Document 1 has a shape in which the flow path of the hot air ejected from the slit once shrinks after the polymer is ejected, and then gradually widens.
  • the jet flows along one wall surface due to the Coanda effect, and is obliquely sprayed against the net conveyor that collects the web.
  • the fibers fly up like feathers above the net conveyor, making it difficult to form a web.
  • the polymer discharged from the nozzle tends to adhere to the constricted portion of the flow channel and the widened flow channel, resulting in shots (polymer clumps), which may make continuous production difficult.
  • the width of the flow path becomes very narrow locally, the pressure loss increases, and it is necessary to improve the performance of the compressor device for supplying the hot air, which may increase the facility cost.
  • the melt-blown nozzle it is possible to obtain the effect of reducing the fiber diameter by increasing the supply pressure of hot air supplied, but the use of compressed air increases utility costs.
  • an object of the present invention is to provide a nonwoven fabric production apparatus and a production method that can efficiently obtain a nonwoven fabric of ultrafine fibers with a very small fiber diameter.
  • the present invention for solving the above problems employs any one of the following configurations. (1) Between a nozzle having an ejection hole group in which ejection holes for ejecting molten polymer are arranged in a row, and a pair of lips arranged to face each other with the ejection hole group of the nozzle interposed therebetween.
  • a pair of widened wall surfaces extending in the direction of polymer discharge from the lower surface of the lip so as to face each other across the polymer discharged from the discharge hole;
  • the angle ⁇ formed by the pair of widening wall surfaces is in the range of 60° ⁇ 120°, and
  • the distance P between the opposing intersections X and the distance H between the opposing intersections Y is in the range of 2 ⁇ H/P ⁇ 15.
  • the "lower surface of the lip” refers to the surface of the lip facing downstream in the direction of polymer ejection.
  • a "slit-shaped gap” refers to a rectangular gap that is arranged substantially parallel to a row of discharge holes and has a cross section that is long in one direction.
  • the "angle ⁇ formed by a pair of widened wall surfaces” is an angle formed by an extension line of a substantially flat wall surface toward the upstream side in the direction of polymer ejection, as shown in FIG.
  • the angle formed by the extension lines of the pair of flat surface portions is adopted. do.
  • the "intersection point of the bottom surface of the lip and the wall surface forming the gap” is also substantially the intersection point of two planes. Take the intersection of the lines. Furthermore, the "intersection point between the bottom surface of the lip and the widened wall surface” refers to the intersection point between the substantially planar widened wall surface and the substantially planar bottom surface of the lip. If so, adopt the intersection of the extensions of the respective planes.
  • defects such as shots can be prevented from occurring by controlling the jet stream directly below the spinneret, making it possible to stably produce a nonwoven fabric of ultrafine fibers.
  • FIG. 1 is a schematic cross-sectional view showing one embodiment of a melt-blown nozzle according to the present invention
  • FIG. FIG. 2 is a schematic cross-sectional view of a conventional melt blow nozzle
  • BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic side view which shows one Embodiment of the manufacturing apparatus of the nonwoven fabric in this invention.
  • FIG. 3 is a schematic diagram showing the direction of airflow directly below the melt-blown nozzle in a conventional example.
  • FIG. 3 is a schematic diagram showing the direction of airflow directly below the melt blow nozzle in the present invention.
  • FIG. 3 is a schematic diagram showing the direction of airflow directly below the melt-blown nozzle in a conventional example.
  • FIG. 4 is a schematic cross-sectional view showing another embodiment of the meltblown nozzle in the present invention
  • FIG. 4 is a schematic cross-sectional view showing still another embodiment of the meltblown nozzle in the present invention
  • 1 is a schematic cross-sectional view showing an embodiment of a meltblown nozzle not included in the present invention
  • FIG. 4 is a schematic cross-sectional view showing another embodiment of a meltblown nozzle not included in the present invention
  • FIG. 4 is a schematic cross-sectional view showing still another embodiment of the meltblown nozzle of the present invention
  • FIG. 1 is a schematic cross-sectional view showing one embodiment of the melt-blown nozzle used in the present invention.
  • FIG. 2 is a schematic cross-sectional view of a conventional melt-blown nozzle without a widened wall surface on the lower surface of the lip.
  • FIG. 3 is a schematic side view showing an example of a nonwoven fabric manufacturing apparatus.
  • FIG. 4 is a diagram showing the direction of the airflow immediately below the melt-blown mouthpiece in the conventional example when no widening wall surface is provided on the lower surface of the lip.
  • FIG. 5 shows the direction of airflow just below the meltblowing nozzle in the embodiment of the present invention.
  • FIG. 6 is a diagram showing the direction of the airflow immediately below the melt-blown nozzle of another conventional example, which has a widened wall surface on the lower surface of the lip but is not included in the present invention.
  • 7 and 8 are schematic cross-sectional views showing another embodiment of the meltblown nozzle of the present invention. 4 to 6, the direction of the arrow indicates the direction of the airflow.
  • the term "immediately below the melt-blowing nozzle” used herein refers to a region below the ejection hole of the nozzle of the melt-blowing nozzle in the direction of polymer ejection.
  • the nonwoven fabric manufacturing apparatus used in the embodiment of the present invention is composed of a polymer introduction pipe 8, a melt blow nozzle 9, a collection net conveyor 10, rollers 11, etc., as shown in FIG.
  • the melt blow nozzle 9 includes a nozzle 1 having a group of discharge holes in which a plurality of discharge holes 2 are arranged in one direction (the depth direction of the paper surface in FIG. 1), and a nozzle 1 with the discharge hole group It has a pair of lips 3 arranged to face each other, and a slit-like gap 4 is formed between the nozzle 1 and each lip 3 .
  • the polymer is supplied from the polymer introduction pipe 8 to the melt blow nozzle 9, and a gas such as high-temperature air is also supplied to the melt blow nozzle 9, and the molten polymer is discharged from the nozzle 1 through the discharge hole 2.
  • the polymer may be directly supplied from the polymer introduction pipe 8 to the melt blow nozzle 9, or may be led to the melt blow nozzle 9 via a spin block (not shown) consisting of a coat hanger die.
  • a gas such as high-temperature air is blown onto the polymer continuously discharged from the discharge hole 2 from the gap 4 formed between the nozzle 1 and the lip 3, thereby pulling the polymer and reducing its diameter.
  • the web 12 is formed by fusion bonding.
  • the web 12 is collected by a collection net conveyor 10 and wound around a roller 11 as a nonwoven fabric.
  • the web 12 may be formed by directly discharging the polymer onto a rotating roller and blowing gas such as high-temperature air.
  • the polymer discharged from the discharge hole 2 is pulled and reduced in diameter in a section (referred to as a stretching section) from the discharge hole 2 to several millimeters in the polymer discharge direction, where the viscosity is low. Therefore, it is important to efficiently generate traction force in this stretched section.
  • the traction force F is given by the formula (A), where CF is a constant, ⁇ is the density of the blown gas, v is the wind speed of the gas in the stretched section, c is the circumferential length of the linear polymer, and l is the length of the stretched section. , proportional to the square of the wind speed v of the airflow and the length l of the stretched section.
  • the width of the flow path is minimized after the flow paths of the ejected gas are merged at the lower end of the slit, and then the width of the flow path is expanded to increase the velocity of the gas. can increase v.
  • this method as shown in FIG. 6, after the polymer is discharged, a portion with a very narrow flow path extends along the direction of polymer discharge, so that the jet flows along one wall surface due to the Coanda effect. easier to flow. As a result, the polymer discharged from the discharge hole 2 cannot flow straight in the discharge direction, and the length l of the stretched section becomes extremely short.
  • the polymer since the polymer is obliquely sprayed onto the collection net conveyor 10, it may be difficult to stably produce a nonwoven fabric of ultrafine fibers.
  • melt-blown nozzles blow out high-speed gas from a pair of gaps 4 and form jets after they collide. very difficult to form.
  • the jet portion is a high-speed region of the airflow blown out from the gap 4 (generally defined Mach number 0.3 or more region), but the section where the wind speed v of this jet section is high is the extension section.
  • a pair of widened wall surfaces 6 extending in the polymer discharge direction are arranged starting from the lower surface of the lip 3 .
  • the angle ⁇ formed by the pair of widening wall surfaces 6 is set within the range of 60° ⁇ 120°.
  • the interval P [mm] between the opposing intersection points X and the opposing intersection points is set to be in the range of 2 ⁇ H/P ⁇ 15.
  • the accompanying flow flows along the widened wall surface 6 and the lower surface of the lip 3 for the jet flow portion blown out from the pair of gaps 4, and flows in the mainstream direction of the jet flow portion (Fig. It flows into the jet part from the opposite direction to the downward direction in the middle.
  • the jet width w is narrowed by the accompanying flows that flowed in from both sides of the nozzle 1, and the cross-sectional area of the jet portion becomes smaller. faster in comparison.
  • the airflow flows along the widened wall surface 6 in a direction opposite to the main flow direction of the jet, thereby suppressing the widening of the jet portion.
  • the jet portion becomes longer in the direction of polymer ejection, and the stretching section l increases.
  • the length l of the stretched section and the wind speed v of the stretched section are increased, so that a nonwoven fabric of ultrafine fibers can be stably produced.
  • the angle ⁇ formed by a pair of opposed widened wall surfaces 6 satisfies the relationship of 60° ⁇ 120°, and between the intersection points X facing each other across the discharge hole 2
  • the interval P [mm] and the interval H [mm] between the intersection points Y facing each other across the discharge hole 2 are adjusted so as to satisfy the relationship 2 ⁇ H/P ⁇ 15.
  • the angle ⁇ is ⁇ >120°, the accompanying flow cannot narrow the jet portion, and the effect of reducing the diameter cannot be obtained.
  • the angle ⁇ is preferably in the range of 70° ⁇ 110°.
  • H/P is preferably in the range of 3 ⁇ H/P ⁇ 8.
  • the interval P [mm] determines the initial width of the jet
  • the interval H [mm] determines the widening of the jet on the downstream side. It is an important parameter for controlling the jet flow and for reducing the diameter.
  • the interval P [mm] between the intersections X facing each other across the discharge hole 2 is in the range of 0.4 ⁇ P ⁇ 4.0. It is necessary to set the air gap width uniformly over the arrangement direction of the discharge holes (apparatus width), but by setting 0.4 ⁇ P, it becomes easy to set the air gap width uniformly across the apparatus width. . On the other hand, by setting P ⁇ 4.0, the jet velocity is increased, making it easier to achieve a smaller diameter.
  • each widened wall surface 6 may be changed arbitrarily.
  • the member 5 forming the widened wall surface 6 may be a block or a plate material, and the lip 3 and the widened wall surface 6 may be integrally constructed.
  • the lip is a part that contributes to forming and regulating the flow path of the gas blown out to the polymer together with the nozzle.
  • the lower surface is the "lower surface of the lip”.
  • the tip of the nozzle 1 may be positioned at the same position as the lower surface of the lip 3 in the direction of polymer ejection as shown in FIG. may be upstream or downstream of the lower surface of the lip.
  • the lower surface of the lip 3 may not be perpendicular to the direction of polymer ejection, and the angle ⁇ formed by the lower surface of the lip and the direction of polymer ejection is 70° ⁇ 120°. is desirable.
  • ⁇ is 70° or more, it is possible to more reliably prevent the accompanying flow from biasing toward the widened wall surface 6 at the ejection portion, thereby facilitating collection by the conveyor belt.
  • ⁇ is larger than 120°, the thickness of the lip tip becomes thin, which makes processing difficult and tends to reduce durability.
  • the length ⁇ of the widened wall surface 6 in the polymer ejection direction is 10 mm or more.
  • the jet portion of the airflow ejected from the gap 4 can be reliably narrowed, so that the effect of reducing the diameter tends to increase.
  • the length ⁇ preferably ranges from 10 mm to 50 mm. By setting the length ⁇ to 50 mm or less, it is possible to further prevent the deviation of the jet portion toward the widened wall surface 6 .
  • the widened wall surface 6 may be composed of two or more widened members, and in this case, it is desirable that the widened member 6 located below in the direction of polymer ejection be detachable.
  • the widening wall surfaces may not be straight but may have steps, but they must be sealed to prevent air from escaping. In this case, ⁇ and H are obtained based on the widening member 6 on the side in contact with the lower surface of the lip 3 .
  • the widening member 5 constituting the widening wall surface 6 is horizontally movable along the lower surface of the lip 3 . This is because polymer may adhere to the widened wall surface 6 when the polymer discharge is unstable, such as when the apparatus starts operating. This is because the widening member 5 is moved to a predetermined position when the discharge state is stabilized.
  • the moving distance is preferably 10 mm or more in the horizontal direction, and particularly preferably 50 mm or more.
  • a heating mechanism for the widened wall surface 6 it is preferable to have a heating mechanism for the widened wall surface 6 .
  • the widening member 5 constituting the widening wall surface 6 is heated by a heating mechanism such as a heater.
  • a heating mechanism such as a heater.
  • a normal temperature accompanying flow flows along the widened wall surface 6 toward the nozzle 1 , so that the tip of the nozzle 1 is easily cooled through the widened member 5 .
  • the melt viscosity of the polymer at the time of ejection increases, which hinders the efficient drawing of the fiber and may reduce the effect of reducing the diameter.
  • a heating mechanism for the widened wall surface 6 to prevent the melt viscosity from increasing during ejection of the polymer.
  • a rod-shaped heater, a plate-shaped heater, and the like can be used, and a plate-shaped heater is more preferable from the viewpoint of uniformity.
  • the heat quantity of the heater is preferably 1.2 KW/m or more.
  • the surface of the widening member may be covered with a heat insulating plate having a low thermal conductivity, and the thermal conductivity is desirably 1.0 W/m/K or less.
  • the widened wall surface 6 may have an R portion that asymptotically approaches the lower surface of the lip 3 in addition to the flat portion.
  • the main point of the present invention is to suppress the expansion of the air jet portion directly under the mouthpiece by the inflow of the accompanying flow along the widening wall surface 6, so that the main flow of the accompanying flow is not affected. Even if the R portion is formed within a range in which there is no R portion, the effect of reducing the diameter is exhibited.
  • the widened wall surface preferably has an arithmetic mean roughness Ra of 100 ⁇ m or less. If the arithmetic mean roughness Ra of the widened wall surface is Ra>100 ⁇ m, the unevenness of the widened wall surface 6 tends to generate eddy currents, resulting in increased turbulence in the entraining flow, which may reduce the effect of reducing the diameter. Moreover, it is preferable that the direction of the knot formed by machining the widened wall surface 6 is parallel to the direction of the airflow near the widened wall surface 6 shown in FIG.
  • Metal materials such as stainless steel and aluminum, and plastic materials such as glass fiber can be preferably used as materials for the widening member used in the present invention.
  • the present invention is an invention with extremely high versatility, and can be applied to the production of known melt-blown nonwoven fabrics. Therefore, the polymer constituting the nonwoven fabric is not particularly limited.
  • polyesters, polyamides, polyphenylene sulfides, polyethylenes, polypropylenes, and the like can be cited as examples of polymers that constitute nonwoven fabrics.
  • the MFR (melt flow rate) of the polymer is preferably 300-1500 g/10 min, more preferably 900-1300 g/10 min.
  • Matting agents such as titanium dioxide, silicon oxide, carion, anti-coloring agents, stabilizers, antioxidants, deodorants, flame retardants, yarn friction reducing agents, and Various functional particles such as coloring pigments and surface modifiers and additives of organic compounds may be contained, and copolymerization may be included.
  • a polymer solution obtained by dissolving a polymer such as cellulose, polysulfone, polyetherimide, or polyacrylonitrile in a solvent may be used.
  • the melting point of the polymer used serves as a guideline for the spinning temperature of the polymer, and it is desirable to set the melting point +60° C. or lower.
  • air is the most economical and preferable gas to be blown from the gap 4, but mixed gas, steam, saturated steam, and superheated steam may also be used.
  • mixed gas, steam, saturated steam, and superheated steam may also be used.
  • it is preferable to select a gas with a high density because the density ⁇ of the gas is also related as shown in the above formula (A).
  • the temperature of the gas is preferably set within a range of +50° C. or less from the temperature of the discharged polymer.
  • ⁇ Misalignment of airflow> The deviation of the airflow is evaluated at the center position of the apparatus width during spinning using an anemometer (Japan Kanomax Co., Ltd.: MODEL6501 series). Specifically, an anemometer probe was installed at a position 10 mm downstream from the nozzle ejection surface in the direction of polymer ejection from the left and right widened wall surfaces and at a position 2 mm inward from the widened wall surface. Measure the wind speed at 10 seconds and use the average value for 10 seconds. If there is a difference of 5 times or more between the obtained wind speed values on the left and right wall surfaces, it is determined that the airflow is biased.
  • an anemometer probe was installed at a position 10 mm downstream from the nozzle ejection surface in the direction of polymer ejection from the left and right widened wall surfaces and at a position 2 mm inward from the widened wall surface. Measure the wind speed at 10 seconds and use the average value for 10 seconds. If there is a difference
  • a non-woven fabric was produced using a melt-blown nozzle as shown in FIG.
  • a polypropylene resin conforming to ASTM-D1238 with a weight of 2.16 kg and a melt flow rate of 1100 g/10 minutes at a temperature of 230°C is used as the raw material resin.
  • the nonwoven fabric could be collected on the conveyor belt, and the average fiber diameter was 1.1 ⁇ m.
  • Examples 1 to 10, Comparative Examples 2 to 6 A nonwoven fabric was produced using a melt-blown nozzle (that is, with a widened wall surface on the lower surface side of the lip) as shown in FIG.
  • a melt-blown nozzle that is, with a widened wall surface on the lower surface side of the lip
  • a polypropylene resin conforming to ASTM-D1238 with a weight of 2.16 kg and a melt flow rate of 1100 g/10 minutes at a temperature of 230°C is used.
  • Comparative Example 2 is the same as Example 2 except that the angle ⁇ formed by the opposing widened wall surfaces is changed to 50°, and the ratio H/P between the interval P between the intersection points X and the interval H between the intersection points Y is changed to 1.
  • the angle ⁇ formed by the opposing widened wall surfaces is changed to 50°
  • the ratio H/P between the interval P between the intersection points X and the interval H between the intersection points Y is changed to 1.
  • Comparative Example 4 an attempt was made to produce a nonwoven fabric in the same manner as in Example 2, except that the ratio H/P between the spacing P between the intersection points X and the spacing H between the intersection points Y was changed to 1.
  • the nonwoven fabric could not be collected on the conveyor belt because the air flow flowed along with the nonwoven fabric.
  • Comparative Example 5 an attempt was made to produce a nonwoven fabric in the same manner as in Example 2, except that the ratio H/P between the spacing P between the intersection points X and the spacing H between the intersection points Y was changed to 21. As a result, a nonwoven fabric was obtained. However, it was not possible to narrow the airflow spouted by the accompanying flow, resulting in a result that the effect of reducing the diameter could not be obtained.
  • Comparative Example 6 an attempt was made to produce a nonwoven fabric in the same manner as in Example 4, except that the angle ⁇ formed by the opposing widened wall surfaces was changed to 150°. As a result, the airflow could not be narrowed and the effect of reducing the diameter could not be obtained.
  • Comparative Example 7 Using a melt - blown nozzle as shown in FIG. Non-woven fabric was manufactured. Table 5 shows the test results. In Comparative Example 7, the nonwoven fabric could be collected on the conveyor belt, and the average fiber diameter was 1.1 ⁇ m.
  • Examples 11 to 13, Comparative Examples 8 and 9 Using a melt - blown nozzle as shown in FIG.
  • the angle ⁇ formed by the lower surface and the polymer ejection direction is 90°
  • the length ⁇ of the widened wall surface in the polymer ejection direction is 30 mm
  • the arithmetic mean roughness Ra of the widened wall surface is 12.5 ⁇ m
  • the widened member is not heated by a heater.
  • a nonwoven fabric was produced under the conditions shown in 5.
  • Comparative Example 8 an attempt was made to produce a nonwoven fabric in the same manner as in Example 11, except that the ratio H/P between the spacing P between the intersection points X and the spacing H between the intersection points Y was changed to 1.
  • the nonwoven fabric could not be collected on the conveyor belt because the air flow flowed along with the nonwoven fabric.
  • Example 14 Using a melt - blown nozzle as shown in FIG.
  • the angle ⁇ between the lower surface and the direction of polymer ejection is 90°
  • the length ⁇ of the widened wall surface in the direction of polymer ejection is 30 mm
  • the arithmetic average roughness Ra of the widened wall surface is 12.5 ⁇ m
  • the widened member is divided into two parts using a plate-shaped heater.
  • a nonwoven fabric was produced under the conditions shown in Table 5 by heating at 0 KW/m (heating surface: opposite side of the widened wall surface).
  • Example 12 Compared to Example 12 in which the widening member was not heated, a nonwoven fabric made of finer fibers could be stably produced.
  • the non-woven fabric produced by the production apparatus and production method of the present invention can be used for industrial material filters, diapers, sanitary products, medical masks, medical gowns, pollen guard masks, sanitary materials such as drapes, automotive materials, liquid filtration filters, and interleaving paper.
  • car wash brushes and other industrial materials food packaging materials, furoshiki cloth, tape yarn, shoe materials, daily life materials such as body warmers, tea bags, and cleaning covers, agricultural materials such as adhesives and agricultural material pots, roof materials, civil engineering stabilizing sheets, and heat insulating materials It can be applied to construction materials such as building materials, floor materials, house wraps, civil engineering materials, etc., but the scope of application is not limited to these.

Abstract

The problem addressed by the invention is that of providing a nonwoven production device and production method with which it is possible to efficiently obtain a microfibre nonwoven having an extremely small fibre diameter.　The nonwoven production device according to the present invention has a slot-shaped gap (4) between a nozzle (1), which has a group of discharge holes in which discharge holes (2) for discharging a molten polymer are arranged in one row, and a pair of lips (3), which are arranged opposite one another with the group of discharge holes of the nozzle (1) in between. Said nonwoven production device sprays gas from the gap (4) onto the polymer discharged from the discharge holes (2) to produce a nonwoven and is characterised in that: a pair of widening wall surfaces (6) that extend in the polymer discharge direction with bottom surfaces of the lips (3) as the starting point thereof are arranged so as to be opposite one another with the polymer discharged from the discharge holes (2) in between; the angle α formed by the pair of widening wall surfaces (6) is in the range of 60°≤α≤120°; and, where (X) are points of intersection between the bottom surfaces of the lips (3) and wall surfaces forming the gap (4), and (Y) are points of intersection between the bottom surfaces of the lips (3) and the widening wall surfaces (6), the distance P between opposite points of intersection (X) and the distance H between opposite points of intersection (Y) are in the range of 2≤H/P≤15.

Description

不織布の製造装置および製造方法NONWOVEN FABRIC MANUFACTURING APPARATUS AND MANUFACTURING METHOD
　本発明は、メルトブロー法による不織布の製造に好適な装置および方法に関する。 The present invention relates to an apparatus and method suitable for manufacturing nonwoven fabrics by the meltblowing method.
　不織布の製造方法の一つとしては、口金のノズルから吐出されたポリマーに、高速かつ高温の気流を吹き付けることで、ポリマーを引っ張りつつ溶融接着させてウエブを形成し、それをネットコンベア上に捕集して不織布を得るメルトブロー法が挙げられる。メルトブロー法で用いられる口金は、幅方向に吐出孔が一列に配列された吐出孔群を有するノズルと、このノズルの両側に吐出孔群を挟んで対向するように配された一対のリップとを有し、ノズルとリップとの間に間隙が形成されている。そして、ノズルの吐出孔から吐出されたポリマーに対して、間隙から高温空気を高圧力下にて高速で吹き出すことで、極細繊維からなる不織布を製造することが可能となる。近年は、この不織布が多種多様な用途へ展開される中で、フィルター、医療用マスク、医療用ガウンなどの高性能用途への展開として、繊維径が非常に小さい不織布が求められている。 In one method of manufacturing nonwoven fabrics, a high-speed, high-temperature air stream is blown onto the polymer extruded from the nozzle of the spinneret to pull and melt-bond the polymer to form a web, which is captured on a net conveyor. A meltblowing method in which a nonwoven fabric is obtained by gathering is mentioned. The die used in the melt blowing method includes a nozzle having a group of discharge holes arranged in a line in the width direction, and a pair of lips arranged on both sides of the nozzle so as to face each other with the group of discharge holes interposed therebetween. A gap is formed between the nozzle and the lip. Then, by blowing high-temperature air from the gap at high speed under high pressure to the polymer discharged from the discharge hole of the nozzle, it is possible to manufacture a nonwoven fabric made of ultrafine fibers. In recent years, nonwoven fabrics have been used in a wide variety of applications, and nonwoven fabrics with very small fiber diameters have been desired for high-performance applications such as filters, medical masks, and medical gowns.
　このような状況の中、不織布の繊維径を小さくする手段として、様々な改善検討が進められてきた。繊維径を小さくするためには、たとえば、口金の一つの吐出孔から吐出されるポリマー量を少なくする方法が挙げられるが、その際には、生産量が低下してしまう問題が生じる。また、ポリマーの吐出量を低下させると、吐出の不安定化が生じることがある。そこで、特許文献１では、メルトブロー口金に関し、スリット（吐出孔）から吐出する溶融ポリマーに対し噴出する熱風の流路幅を、該熱風がスリット下端部でポリマーと合流する地点以降で最小化し、その後に徐々に拡大させることが開示されている。これによれば、最小流路幅の部位において熱風が音速に達し、その後に熱風が緩やかに断熱膨張することで、効率的に繊維を細径化できる。 Under these circumstances, various improvement studies have been carried out as a means of reducing the fiber diameter of nonwoven fabrics. In order to reduce the fiber diameter, for example, there is a method of reducing the amount of polymer ejected from one ejection hole of the die, but in that case, the problem arises that the production amount decreases. Further, when the ejection amount of the polymer is lowered, the ejection may become unstable. Therefore, in Patent Document 1, regarding a melt blow nozzle, the flow path width of hot air ejected against the molten polymer discharged from the slit (discharge hole) is minimized after the point where the hot air joins the polymer at the lower end of the slit, and then is gradually increased to . According to this, the hot air reaches the speed of sound at the portion of the minimum flow path width, and then the hot air gently adiabatically expands, so that the diameter of the fibers can be efficiently reduced.
特開昭５１－６７４１１号公報JP-A-51-67411
　しかしながら、特許文献１に開示されているメルトブロー口金は、スリットから噴出された熱風の流路が、ポリマー噴出後に一旦縮流し、その後徐々に拡幅する形状をしている。そのため、噴流がコアンダ効果にて一方の壁面に沿ってしまい、ウエブを捕集するネットコンベアに対して斜めに吹き付けられる。その結果、ネットコンベアの上方にて繊維が羽毛のように舞い上がってしまい、ウエブを形成することが困難となる場合がある。また、ノズルから吐出されたポリマーが、流路の縮流部および拡幅流路に付着しやすくなり、ショット（ポリマーの塊）が発生し、連続生産が困難となる場合がある。さらに、流路幅が局所的に非常に狭くなるため、圧力損失が高くなり、必然的に熱風を供給するためのコンプレッサ装置性能を高める必要があり、設備費が高くなる場合がある。また、メルトブロー口金においては、供給する熱風の供給圧を高めることで、繊維径の細径化の効果を得ることが可能であるが、圧空エアを用いることから用役費が高くなる。 However, the melt-blown nozzle disclosed in Patent Document 1 has a shape in which the flow path of the hot air ejected from the slit once shrinks after the polymer is ejected, and then gradually widens. As a result, the jet flows along one wall surface due to the Coanda effect, and is obliquely sprayed against the net conveyor that collects the web. As a result, the fibers fly up like feathers above the net conveyor, making it difficult to form a web. In addition, the polymer discharged from the nozzle tends to adhere to the constricted portion of the flow channel and the widened flow channel, resulting in shots (polymer clumps), which may make continuous production difficult. Furthermore, since the width of the flow path becomes very narrow locally, the pressure loss increases, and it is necessary to improve the performance of the compressor device for supplying the hot air, which may increase the facility cost. In addition, in the melt-blown nozzle, it is possible to obtain the effect of reducing the fiber diameter by increasing the supply pressure of hot air supplied, but the use of compressed air increases utility costs.
　よって、本発明の目的は、繊維径が非常に小さい極細繊維の不織布を効率的に得ることができる不織布の製造装置および製造方法を提供することにある。 Therefore, an object of the present invention is to provide a nonwoven fabric production apparatus and a production method that can efficiently obtain a nonwoven fabric of ultrafine fibers with a very small fiber diameter.
　上記課題を解決するための本発明は、以下のいずれかの構成を採用する。
（１）　溶融したポリマーを吐出するための吐出孔が１列に配された吐出孔群を有するノズルと、前記ノズルの吐出孔群を挟んで対向するように配された一対のリップとの間に、スリット状のギャップを有し、前記吐出孔より吐出したポリマーに対して前記ギャップから気体を吹き付けて不織布を製造する装置であって、
前記吐出孔より吐出されるポリマーを挟んで対向するように、前記リップの下面を起点に、ポリマー吐出方向に延在する一対の拡幅壁面を配し、
前記一対の拡幅壁面の成す角度αが６０°≦α≦１２０°の範囲であり、且つ、
前記リップの下面と前記ギャップを形成する壁面の交点をＸ、前記リップの下面と前記拡幅壁面の交点をＹとしたとき、対向する交点Ｘ間の間隔Ｐと、対向する交点Ｙ間の間隔Ｈとが、２≦Ｈ／Ｐ≦１５の範囲である
ことを特徴とする不織布の製造装置。
（２）　前記リップの下面とポリマー吐出方向との成す角度βが、７０°≦β≦１２０°である、前記（１）に記載の不織布の製造装置。
（３）　前記拡幅壁面のポリマー吐出方向の長さγが１０ｍｍ以上である、前記（１）または（２）に記載の不織布の製造装置。
（４）　前記拡幅壁面がポリマー吐出方向と交差する方向に移動可能である、前記（１）～（３）のいずれかに記載の不織布の製造装置。
（５）　前記拡幅壁面の算術平均粗さＲａが１００μｍ以下である、前記（１）～（４）のいずれかに記載の不織布の製造装置。
（６）　前記拡幅壁面の加熱機構を有している、前記（１）～（５）のいずれかに記載の不織布の製造装置。
（７）　前記（１）～（６）のいずれかの装置を用いた不織布の製造方法。 The present invention for solving the above problems employs any one of the following configurations.
(1) Between a nozzle having an ejection hole group in which ejection holes for ejecting molten polymer are arranged in a row, and a pair of lips arranged to face each other with the ejection hole group of the nozzle interposed therebetween. and a slit-shaped gap for manufacturing a nonwoven fabric by blowing gas from the gap against the polymer discharged from the discharge hole,
a pair of widened wall surfaces extending in the direction of polymer discharge from the lower surface of the lip so as to face each other across the polymer discharged from the discharge hole;
The angle α formed by the pair of widening wall surfaces is in the range of 60°≦α≦120°, and
When the intersection of the lower surface of the lip and the wall surface forming the gap is X, and the intersection of the lower surface of the lip and the widened wall surface is Y, the distance P between the opposing intersections X and the distance H between the opposing intersections Y is in the range of 2≦H/P≦15.
(2) The apparatus for producing a nonwoven fabric according to (1) above, wherein the angle β between the lower surface of the lip and the direction of polymer discharge is 70°≦β≦120°.
(3) The apparatus for producing a nonwoven fabric according to (1) or (2) above, wherein the widened wall surface has a length γ of 10 mm or more in the polymer discharge direction.
(4) The apparatus for producing a nonwoven fabric according to any one of (1) to (3), wherein the widened wall surface is movable in a direction intersecting the direction of polymer ejection.
(5) The apparatus for producing a nonwoven fabric according to any one of (1) to (4), wherein the widened wall surface has an arithmetic mean roughness Ra of 100 μm or less.
(6) The apparatus for producing a nonwoven fabric according to any one of (1) to (5) above, which has a heating mechanism for the widened wall surface.
(7) A method for producing a nonwoven fabric using the apparatus according to any one of (1) to (6).
　なお、本発明において「リップの下面」とは、リップのポリマー吐出方向下流側に面した面のことを言う。 In the present invention, the "lower surface of the lip" refers to the surface of the lip facing downstream in the direction of polymer ejection.
　本発明において「スリット状のギャップ」とは、１列に配置された吐出孔群と略平行に配置され、断面が一方向に長い長方形状のギャップのことを言う。 In the present invention, a "slit-shaped gap" refers to a rectangular gap that is arranged substantially parallel to a row of discharge holes and has a cross section that is long in one direction.
　本発明において「一対の拡幅壁面の成す角度α」とは、図１に示すように、実質的に平面の壁面の、ポリマー吐出方向上流側への延長線によって形成される角度であるが、例えば一対の平面壁面がリップ側にＲ部を有する場合など、平面部とともにポリマー吐出方向に拡幅角度が変化している部分を有する拡幅壁面の場合は、一対の平面部の延長線のなす角度を採用する。 In the present invention, the "angle α formed by a pair of widened wall surfaces" is an angle formed by an extension line of a substantially flat wall surface toward the upstream side in the direction of polymer ejection, as shown in FIG. In the case of a pair of flat wall surfaces having a curved portion on the lip side, in the case of a widened wall surface having a portion where the widening angle changes in the direction of polymer ejection along with the flat surface portion, the angle formed by the extension lines of the pair of flat surface portions is adopted. do.
　「リップの下面とギャップを形成する壁面の交点」についても、実質的に２つの平面の交点をいうが、交点に相当する位置がＲ部で形成されている場合には、それぞれの平面の延長線の交点を採用する。さらに、「リップの下面と前記拡幅壁面の交点」とは、実質的に平面の拡幅壁面と実質的に平面のリップ下面との交点をいうが、交点に相当する位置がＲ部で形成されている場合には、それぞれの平面の延長線の交点を採用する。 The "intersection point of the bottom surface of the lip and the wall surface forming the gap" is also substantially the intersection point of two planes. Take the intersection of the lines. Furthermore, the "intersection point between the bottom surface of the lip and the widened wall surface" refers to the intersection point between the substantially planar widened wall surface and the substantially planar bottom surface of the lip. If so, adopt the intersection of the extensions of the respective planes.
　本発明によれば、口金直下の噴流を制御することで、ショット等の欠点発生を防ぎ、安定的に極細繊維の不織布を製造することができる。 According to the present invention, defects such as shots can be prevented from occurring by controlling the jet stream directly below the spinneret, making it possible to stably produce a nonwoven fabric of ultrafine fibers.
本発明におけるメルトブロー口金の一実施形態を示す概略断面図である。1 is a schematic cross-sectional view showing one embodiment of a melt-blown nozzle according to the present invention; FIG. 従来例におけるメルトブロー口金の概略断面図である。FIG. 2 is a schematic cross-sectional view of a conventional melt blow nozzle; 本発明における不織布の製造装置の一実施形態を示す概略側面図である。BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic side view which shows one Embodiment of the manufacturing apparatus of the nonwoven fabric in this invention. 従来例におけるメルトブロー口金の直下での気流の向きを示した模式図である。FIG. 3 is a schematic diagram showing the direction of airflow directly below the melt-blown nozzle in a conventional example. 本発明におけるメルトブロー口金の直下での気流の向きを示した模式図である。FIG. 3 is a schematic diagram showing the direction of airflow directly below the melt blow nozzle in the present invention. 従来例におけるメルトブロー口金の直下での気流の向きを示した模式図である。FIG. 3 is a schematic diagram showing the direction of airflow directly below the melt-blown nozzle in a conventional example. 本発明におけるメルトブロー口金の別の実施形態を示す概略断面図である。FIG. 4 is a schematic cross-sectional view showing another embodiment of the meltblown nozzle in the present invention; 本発明におけるメルトブロー口金のさらに別の実施形態を示す概略断面図である。FIG. 4 is a schematic cross-sectional view showing still another embodiment of the meltblown nozzle in the present invention; 本発明に含まれないメルトブロー口金の実施形態を示す概略断面図である。1 is a schematic cross-sectional view showing an embodiment of a meltblown nozzle not included in the present invention; FIG. 本発明に含まれないメルトブロー口金の別の実施形態を示す概略断面図である。FIG. 4 is a schematic cross-sectional view showing another embodiment of a meltblown nozzle not included in the present invention; 本発明におけるメルトブロー口金のさらに別に実施形態を示す概略断面図である。FIG. 4 is a schematic cross-sectional view showing still another embodiment of the meltblown nozzle of the present invention;
　以下、図面を参照しながら、本発明の不織布の製造装置および製造方法について詳細に説明する。図１は、本発明に用いられるメルトブロー口金の一実施形態を示す概略断面図である。図２は、従来例の、リップ下面に拡幅壁面がないメルトブロー口金の概略断面図である。図３は不織布の製造装置例を示す概略側面図である。図４は、従来例の、リップ下面に拡幅壁面を設置しない場合における、メルトブロー口金直下での気流の向きを示す図である。図５は、本発明の実施形態における、メルトブロー口金直下での気流の向きを示す。図６は、リップ下面に拡幅壁面を設置するが、本発明には含まれない別の従来例の、メルトブロー口金直下での気流の向きを示す図である。図７、８は、本発明におけるメルトブロー口金の別の実施形態を示す概略断面図である。なお、図４～６において、矢印の向きは気流の向きを示す。また、ここでいう、「メルトブロー口金直下」とは、メルトブロー口金のノズルの吐出孔よりポリマー吐出方向に対して下方の領域を示す。そして、これらの図は、本発明の要点を正確に伝えるための概略図であり、図を簡略化しており、本発明におけるメルトブロー口金は、特に制限されるものではなく、また、寸法比などは実施の形態に合わせて変更可能である。 The nonwoven fabric manufacturing apparatus and manufacturing method of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing one embodiment of the melt-blown nozzle used in the present invention. FIG. 2 is a schematic cross-sectional view of a conventional melt-blown nozzle without a widened wall surface on the lower surface of the lip. FIG. 3 is a schematic side view showing an example of a nonwoven fabric manufacturing apparatus. FIG. 4 is a diagram showing the direction of the airflow immediately below the melt-blown mouthpiece in the conventional example when no widening wall surface is provided on the lower surface of the lip. FIG. 5 shows the direction of airflow just below the meltblowing nozzle in the embodiment of the present invention. FIG. 6 is a diagram showing the direction of the airflow immediately below the melt-blown nozzle of another conventional example, which has a widened wall surface on the lower surface of the lip but is not included in the present invention. 7 and 8 are schematic cross-sectional views showing another embodiment of the meltblown nozzle of the present invention. 4 to 6, the direction of the arrow indicates the direction of the airflow. In addition, the term "immediately below the melt-blowing nozzle" used herein refers to a region below the ejection hole of the nozzle of the melt-blowing nozzle in the direction of polymer ejection. These drawings are schematic diagrams for accurately conveying the gist of the present invention, and the drawings are simplified. The melt-blown nozzle in the present invention is not particularly limited, and the dimensional ratios It can be changed according to the embodiment.
　本発明の実施形態に用いられる不織布の製造装置は、図３に示すように、ポリマー導入管８、メルトブロー口金９、捕集ネットコンベア１０、ローラー１１などから構成される。メルトブロー口金９は、図１に示すように、複数の吐出孔２が一方向（図１における紙面奥行き方向）に配された吐出孔群を有するノズル１と、ノズル１の吐出孔群を挟んで対向するように配された一対のリップ３とを有し、ノズル１とそれぞれのリップ３との間には、スリット状のギャップ４が形成されている。 　The nonwoven fabric manufacturing apparatus used in the embodiment of the present invention is composed of a polymer introduction pipe 8, a melt blow nozzle 9, a collection net conveyor 10, rollers 11, etc., as shown in FIG. As shown in FIG. 1, the melt blow nozzle 9 includes a nozzle 1 having a group of discharge holes in which a plurality of discharge holes 2 are arranged in one direction (the depth direction of the paper surface in FIG. 1), and a nozzle 1 with the discharge hole group It has a pair of lips 3 arranged to face each other, and a slit-like gap 4 is formed between the nozzle 1 and each lip 3 .
　このような装置構成において、ポリマーをポリマー導入管８よりメルトブロー口金９に供給するとともに、高温空気などの気体もメルトブロー口金９に供給し、ノズル１の吐出孔２から溶融ポリマーを吐出する。このとき、ポリマーは、ポリマー導入管８からメルトブロー口金９に直接供給しても良いが、コートハンガーダイからなるスピンブロック（図示なし）を介してメルトブロー口金９に導いてもよい。その後、吐出孔２から連続的に吐出されたポリマーに、ノズル１とリップ３との間に形成されたギャップ４より高温空気などの気体を吹き付けることで、ポリマーを牽引し、細径化しつつ、溶融接着させてウエブ１２を形成する。そのウエブ１２を捕集ネットコンベア１０にて捕集し、不織布としてローラー１１に巻き取る。なお、捕集ネットコンベア１０を用いずに、直接、回転しているローラーにポリマーを吐出し、高温空気などの気体を吹き付けることでウエブ１２を形成してもよい。 In such an apparatus configuration, the polymer is supplied from the polymer introduction pipe 8 to the melt blow nozzle 9, and a gas such as high-temperature air is also supplied to the melt blow nozzle 9, and the molten polymer is discharged from the nozzle 1 through the discharge hole 2. At this time, the polymer may be directly supplied from the polymer introduction pipe 8 to the melt blow nozzle 9, or may be led to the melt blow nozzle 9 via a spin block (not shown) consisting of a coat hanger die. Thereafter, a gas such as high-temperature air is blown onto the polymer continuously discharged from the discharge hole 2 from the gap 4 formed between the nozzle 1 and the lip 3, thereby pulling the polymer and reducing its diameter. The web 12 is formed by fusion bonding. The web 12 is collected by a collection net conveyor 10 and wound around a roller 11 as a nonwoven fabric. Instead of using the collection net conveyor 10, the web 12 may be formed by directly discharging the polymer onto a rotating roller and blowing gas such as high-temperature air.
　ここで、吐出孔２から吐出されたポリマーは、粘度が低い状態である、吐出孔２からポリマーの吐出方向に数ミリまでの区間（延伸区間と呼ぶ）にて、牽引され細径化されるため、この延伸区間で効率的に牽引力を発現させることが重要となる。ここで牽引力Ｆは、定数をＣＦ、吹き付ける気体の密度ρ、延伸区間での気体の風速ｖ、線状となるポリマーの円周長さｃ、延伸区間の長さｌとすると、式（Ａ）に示すように、気流の風速ｖの２乗、延伸区間の長さｌに比例する。 Here, the polymer discharged from the discharge hole 2 is pulled and reduced in diameter in a section (referred to as a stretching section) from the discharge hole 2 to several millimeters in the polymer discharge direction, where the viscosity is low. Therefore, it is important to efficiently generate traction force in this stretched section. Here, the traction force F is given by the formula (A), where CF is a constant, ρ is the density of the blown gas, v is the wind speed of the gas in the stretched section, c is the circumferential length of the linear polymer, and l is the length of the stretched section. , proportional to the square of the wind speed v of the airflow and the length l of the stretched section.
　　　　Ｆ＝ＣＦ×ρ×ｖ２×ｃ×ｌ　　式（Ａ）
　そのため、牽引力Ｆを効率的に増加させる方法としては、延伸区間での気体の風速ｖと延伸区間の長さｌを増加させることが考えられる。 F=CF×ρ×v 2 ×c×l Formula (A)
Therefore, as a method for efficiently increasing the traction force F, it is conceivable to increase the wind speed v of the gas in the stretched section and the length l of the stretched section.
　その手段として、例えば前述の特許文献１に示すように、噴出する気体の流路をスリット下端部で合流させた後に流路幅を最小化し、その後流路幅を拡大することで、気体の速度ｖを高めることができる。しかしながら、かかる方法によると、図６に示すように、ポリマー吐出後に非常に流路幅の狭い部分がポリマー吐出方向に沿って延在することから、噴流がコアンダ効果にて一方の壁面に沿って流れやすくなる。その結果、吐出孔２から吐出されたポリマーが吐出方向に直進して流れることが出来ず、延伸区間の長さｌが極めて短くなる。また、前述の通り、ポリマーが捕集ネットコンベア１０に対して斜めに吹き付けられることから、安定して極細繊維の不織布を製造することが困難となる場合がある。 As a means for achieving this, for example, as shown in the above-mentioned Patent Document 1, the width of the flow path is minimized after the flow paths of the ejected gas are merged at the lower end of the slit, and then the width of the flow path is expanded to increase the velocity of the gas. can increase v. However, according to this method, as shown in FIG. 6, after the polymer is discharged, a portion with a very narrow flow path extends along the direction of polymer discharge, so that the jet flows along one wall surface due to the Coanda effect. easier to flow. As a result, the polymer discharged from the discharge hole 2 cannot flow straight in the discharge direction, and the length l of the stretched section becomes extremely short. In addition, as described above, since the polymer is obliquely sprayed onto the collection net conveyor 10, it may be difficult to stably produce a nonwoven fabric of ultrafine fibers.
　また、一般的にメルトブロー口金では、一対のギャップ４より高速の気体を吹き出し、衝突させた後に噴流を形成することから、気流乱れが非常に大きくなりやすく、口金直下にて安定的に噴流部を形成することが非常に難しい。なお、噴流部とは、ギャップ４から吹き出した気流の高速領域（一般的に定義されるマッハ数０．３以上の領域）であるが、この噴流部の風速ｖが高い区間が、延伸区間となる。したがって、安定して極細繊維の不織布を製造するためには、メルトブロー口金の直下において、安定的に延伸区間の長さｌを十分に確保しつつ、その区間において風速ｖを増加させることが必要となる。 In general, melt-blown nozzles blow out high-speed gas from a pair of gaps 4 and form jets after they collide. very difficult to form. Note that the jet portion is a high-speed region of the airflow blown out from the gap 4 (generally defined Mach number 0.3 or more region), but the section where the wind speed v of this jet section is high is the extension section. Become. Therefore, in order to stably produce a nonwoven fabric of ultrafine fibers, it is necessary to stably secure a sufficient length l of the stretched section immediately below the melt blow nozzle and increase the wind speed v in that section. Become.
　そこで、本発明者らは、従来の技術では、何の配慮もされていなかった、上記問題に対して、鋭意検討を重ねた結果、本発明の新たな技術を見出すに至った。すなわち、本発明においては、図１、５に示すように、リップ３の下面を起点に、ポリマー吐出方向に延在する一対の拡幅壁面６を配置させる。そして、一対の拡幅壁面６の成す角度αを６０°≦α≦１２０°の範囲とする。また、リップ３の下面とギャップ４を形成する壁面との交点Ｘ、リップ３の下面と拡幅壁面６の交点をＹとするとき、対向する交点Ｘ間の間隔Ｐ［ｍｍ］と、対向する交点Ｙ間の間隔Ｈ［ｍｍ］とが、２≦Ｈ／Ｐ≦１５の範囲となるようにする。 Therefore, the inventors of the present invention have found the new technology of the present invention as a result of extensive studies on the above problems, which were not considered in the conventional technology. That is, in the present invention, as shown in FIGS. 1 and 5, a pair of widened wall surfaces 6 extending in the polymer discharge direction are arranged starting from the lower surface of the lip 3 . The angle α formed by the pair of widening wall surfaces 6 is set within the range of 60°≦α≦120°. Further, when the intersection point X between the lower surface of the lip 3 and the wall surface forming the gap 4 and the intersection point between the lower surface of the lip 3 and the widened wall surface 6 are Y, the interval P [mm] between the opposing intersection points X and the opposing intersection points The interval H [mm] between Ys is set to be in the range of 2≦H/P≦15.
　ここで、従来例の実施形態（図４）と、上記構成の拡幅壁面を有する本発明の実施形態（図５）における口金直下での気流の形態の差を説明する。図４に示す従来例の実施形態では、１対のギャップ４から吹き出した高速の気体が互いに衝突して噴流部を形成し、噴流部の気体が、対向する交点Ｘの隙間から下方に向かって拡散される。その際に、リップ３の下面に沿って、随伴流が噴流部に対しておおよそ垂直に流入し、この随伴流を巻き込みながら、徐々に噴流部が拡幅していく。この噴流部によって、繊維状のポリマーは、延伸された後に減速し、ネットコンベア１０に着地する。一方で、図５に示す本発明の実施形態では、１対のギャップ４から吹き出した噴流部に対して、随伴流が拡幅壁面６とリップ３下面に沿って流れ、噴流部の主流方向（図中の下向き）とは逆向する方向から噴流部に流入する。その結果、口金直下の噴流部では、ノズル１の両側から流れ込んだ随伴流によって噴流幅ｗが押し狭められて噴流部の断面積が小さくなり、延いては、延伸区間の風速ｖが従来例に比べて速くなる。さらに、噴流の主流方向とは逆向するように拡幅壁面６に沿って気流が流れこむことで、噴流部の拡幅が抑制される。その結果、ポリマー吐出方向に噴流部が長くなり、延伸区間ｌが増加する。このように、本発明の実施形態のメルトブロー口金では、延伸区間の長さｌとその区間の風速ｖが高まることで、安定して極細繊維の不織布を製造することができる。 Here, the difference in the form of airflow immediately below the mouthpiece between the conventional embodiment (Fig. 4) and the embodiment of the present invention (Fig. 5) having the widened wall surface configured as described above will be described. In the embodiment of the conventional example shown in FIG. 4, high-speed gas blown out from a pair of gaps 4 collides with each other to form a jet portion, and the gas in the jet portion flows downward from the gap at the intersection point X facing each other. be diffused. At that time, an accompanying flow flows into the jet portion along the lower surface of the lip 3 approximately perpendicularly, and the jet portion gradually expands in width while involving the accompanying flow. By this jet portion, the fibrous polymer is decelerated after being stretched and lands on the net conveyor 10 . On the other hand, in the embodiment of the present invention shown in FIG. 5, the accompanying flow flows along the widened wall surface 6 and the lower surface of the lip 3 for the jet flow portion blown out from the pair of gaps 4, and flows in the mainstream direction of the jet flow portion (Fig. It flows into the jet part from the opposite direction to the downward direction in the middle. As a result, in the jet portion immediately below the mouthpiece, the jet width w is narrowed by the accompanying flows that flowed in from both sides of the nozzle 1, and the cross-sectional area of the jet portion becomes smaller. faster in comparison. Further, the airflow flows along the widened wall surface 6 in a direction opposite to the main flow direction of the jet, thereby suppressing the widening of the jet portion. As a result, the jet portion becomes longer in the direction of polymer ejection, and the stretching section l increases. As described above, in the melt-blown nozzle of the embodiment of the present invention, the length l of the stretched section and the wind speed v of the stretched section are increased, so that a nonwoven fabric of ultrafine fibers can be stably produced.
　本発明においては、上記したように、対向する一対の拡幅壁面６のなす角度αが、６０°≦α≦１２０°の関係を満足した上で、吐出孔２を挟んで対向する交点Ｘ間の間隔Ｐ［ｍｍ］と、吐出孔２を挟んで対向する交点Ｙ間の間隔Ｈ［ｍｍ］とが、２≦Ｈ／Ｐ≦１５の関係を満足するように調整するが、Ｈ／Ｐが２≦Ｈ／Ｐ≦１５の関係を満足しても、特許文献１に示すように前記角度αがα＜６０°の場合には、図９に示すように、吐出したポリマーが一方の拡幅壁面６に偏ってしまい、安定して極細繊維の不織布を得ることが困難となる。一方、前記角度αがα＞１２０°の場合には、随伴流が噴流部を狭めることができず、細径化の効果が得られない。 In the present invention, as described above, the angle α formed by a pair of opposed widened wall surfaces 6 satisfies the relationship of 60°≦α≦120°, and between the intersection points X facing each other across the discharge hole 2 The interval P [mm] and the interval H [mm] between the intersection points Y facing each other across the discharge hole 2 are adjusted so as to satisfy the relationship 2≦H/P≦15. Even if the relationship ≦H/P≦15 is satisfied, when the angle α is less than 60° as shown in Patent Document 1, as shown in FIG. , making it difficult to stably obtain a nonwoven fabric of ultrafine fibers. On the other hand, when the angle α is α>120°, the accompanying flow cannot narrow the jet portion, and the effect of reducing the diameter cannot be obtained.
　また、前記角度αが６０°≦α≦１２０°の関係を満足しても、Ｈ／Ｐ＜２の場合には、図１０に示すように、吐出したポリマーが一方の拡幅壁面６に偏ってしまい、安定して極細繊維の不織布を得ることが困難となる。また、Ｈ／Ｐ＞１５の場合にも、随伴流が噴流部を狭めることができず、細径化の効果が得られない。本発明においては、６０°≦α≦１２０°かつ２≦Ｈ／Ｐ≦１５を満足するように調整することで、ノズル１の直下の噴流を制御し、安定して極細繊維の不織布を製造することができる。 Even if the angle α satisfies the relationship of 60°≦α≦120°, when H/P<2, as shown in FIG. This makes it difficult to stably obtain a nonwoven fabric of ultrafine fibers. Also, when H/P>15, the accompanying flow cannot narrow the jet portion, and the effect of reducing the diameter cannot be obtained. In the present invention, by adjusting so as to satisfy 60° ≤ α ≤ 120° and 2 ≤ H/P ≤ 15, the jet stream directly below the nozzle 1 is controlled and a nonwoven fabric of ultrafine fibers is stably produced. be able to.
　前記角度αは、７０°≦α≦１１０°の範囲であることが好ましい。また、Ｈ／Ｐは、３≦Ｈ／Ｐ≦８の範囲であることが好ましい。つまりは、間隔Ｐ［ｍｍ］は噴流部の初期の幅を決定しつつ、間隔Ｈ［ｍｍ］は、その噴流の下流側における噴流の拡幅を決定することになるため、この比率Ｈ／Ｐが噴流の制御、延いては細径化に重要なパラメータとなる。 The angle α is preferably in the range of 70°≦α≦110°. Also, H/P is preferably in the range of 3≤H/P≤8. In other words, while the interval P [mm] determines the initial width of the jet, the interval H [mm] determines the widening of the jet on the downstream side. It is an important parameter for controlling the jet flow and for reducing the diameter.
　本発明においては、吐出孔２を挟んで対向する交点Ｘ間の間隔Ｐ［ｍｍ］は、０．４≦Ｐ≦４．０の範囲であることが好ましい。エアギャップ幅は吐出孔の配列方向（装置幅）に亘って均一に設定する必要があるが、０．４≦Ｐとすることで該エアギャップ幅を装置幅に亘って均一に設定しやすくなる。一方、Ｐ≦４．０とすることで噴流速度を早くして細径化をより達成しやすくなる。 In the present invention, it is preferable that the interval P [mm] between the intersections X facing each other across the discharge hole 2 is in the range of 0.4≤P≤4.0. It is necessary to set the air gap width uniformly over the arrangement direction of the discharge holes (apparatus width), but by setting 0.4≦P, it becomes easy to set the air gap width uniformly across the apparatus width. . On the other hand, by setting P≦4.0, the jet velocity is increased, making it easier to achieve a smaller diameter.
　一対の拡幅壁面６は、任意に各拡幅壁面６の傾きを変更できることが望ましい。拡幅壁面６を構成する部材５はブロックでも板材でも良く、リップ３と拡幅壁面６とが一体構成であっても良い。なお、リップは、ポリマーに対して吹き出される気体の流路を、ノズルと共に形成・規制するのに寄与する部位であり、一体構成の場合、該部位の気体を吹き出す先端（交点Ｘ）を含む下面が「リップの下面」となる。 It is desirable that the inclination of each widened wall surface 6 can be changed arbitrarily. The member 5 forming the widened wall surface 6 may be a block or a plate material, and the lip 3 and the widened wall surface 6 may be integrally constructed. The lip is a part that contributes to forming and regulating the flow path of the gas blown out to the polymer together with the nozzle. The lower surface is the "lower surface of the lip".
　本発明においては、図１に示すようにノズル１の先端がポリマー吐出方向に対してリップ３の下面と同じ位置であってもよいが、図１１に示すようにノズル１の先端がポリマー吐出方向に対してリップの下面よりも上流側であってもよいし、また下流側にあっても良い。 In the present invention, the tip of the nozzle 1 may be positioned at the same position as the lower surface of the lip 3 in the direction of polymer ejection as shown in FIG. may be upstream or downstream of the lower surface of the lip.
　本発明においては、図７に示すように、リップ３の下面がポリマー吐出方向に対して垂直でなくとも良く、前記リップの下面とポリマー吐出方向の成す角度βが、７０°≦β≦１２０°であることが望ましい。βを７０°以上とすることで、噴出部にて随伴流が拡幅壁面６に偏ることをより確実に防いでコンベアベルトでの捕集をより容易にできる。ただし、βが１２０°より大きくなると、リップ先端厚みが薄くなることから、加工が困難なことに加えて耐久性が低下しやすくなる。 In the present invention, as shown in FIG. 7, the lower surface of the lip 3 may not be perpendicular to the direction of polymer ejection, and the angle β formed by the lower surface of the lip and the direction of polymer ejection is 70°≦β≦120°. is desirable. By setting β to 70° or more, it is possible to more reliably prevent the accompanying flow from biasing toward the widened wall surface 6 at the ejection portion, thereby facilitating collection by the conveyor belt. However, if β is larger than 120°, the thickness of the lip tip becomes thin, which makes processing difficult and tends to reduce durability.
　本発明においては、拡幅壁面６のポリマー吐出方向の長さγが１０ｍｍ以上であることが好ましい。γを１０ｍｍ以上とすることで、ギャップ４から噴出した気流の噴流部を確実に狭くできることから、細径化の効果が高まりやすくなる。特に該長さγは、１０ｍｍから５０ｍｍの範囲であることが好ましい。該長さγを５０ｍｍ以下とすることで、噴流部の拡幅壁面６への偏りをさらに防ぐことができる。また、拡幅壁面６は、２つ以上の拡幅部材で構成されていてもよく、その場合、ポリマー吐出方向に下方の拡幅部材６を着脱可能とすることが望ましい。２つ以上の拡幅部材６の接続面においては、拡幅壁面が１直線でなく、段差が生じている構成であっても良いが、空気が抜けないようにシールされている必要がある。なお、その場合、前記αやＨは、リップ３の下面に接している側の拡幅部材６を基準に求める。 In the present invention, it is preferable that the length γ of the widened wall surface 6 in the polymer ejection direction is 10 mm or more. By setting γ to 10 mm or more, the jet portion of the airflow ejected from the gap 4 can be reliably narrowed, so that the effect of reducing the diameter tends to increase. In particular, the length γ preferably ranges from 10 mm to 50 mm. By setting the length γ to 50 mm or less, it is possible to further prevent the deviation of the jet portion toward the widened wall surface 6 . Further, the widened wall surface 6 may be composed of two or more widened members, and in this case, it is desirable that the widened member 6 located below in the direction of polymer ejection be detachable. At the connecting surfaces of two or more widening members 6, the widening wall surfaces may not be straight but may have steps, but they must be sealed to prevent air from escaping. In this case, α and H are obtained based on the widening member 6 on the side in contact with the lower surface of the lip 3 .
　本発明においては、拡幅壁面６を構成する拡幅部材５が、リップ３の下面に沿って、水平方向に移動可能であることが好ましい。これは、装置の運転開始時などポリマー吐出が不安定な状態では拡幅壁面６にポリマーが付着する可能性があるため、運転開始時などには拡幅壁面６をノズル１の吐出孔２から離しておき、吐出状態が安定した段階で、拡幅部材５を所定の位置に移動するためである。移動距離については、水平方向に１０ｍｍ以上であることが好ましく、特に５０ｍｍ以上が好ましい。この際の拡幅部材５の移動には、ボルトの押し引き、送りねじやレール機構を用いるのが好ましい。 In the present invention, it is preferable that the widening member 5 constituting the widening wall surface 6 is horizontally movable along the lower surface of the lip 3 . This is because polymer may adhere to the widened wall surface 6 when the polymer discharge is unstable, such as when the apparatus starts operating. This is because the widening member 5 is moved to a predetermined position when the discharge state is stabilized. The moving distance is preferably 10 mm or more in the horizontal direction, and particularly preferably 50 mm or more. For the movement of the widening member 5 at this time, it is preferable to use a bolt pushing/pulling, a feed screw, or a rail mechanism.
　また、本発明においては、拡幅壁面６の加熱機構を有していることが好ましい。具体的には、例えば拡幅壁面６を構成する拡幅部材５が、ヒーター等の加熱機構により加熱されていることが望ましい。本発明においては、拡幅壁面６に沿ってノズル１に向かって例えば常温の随伴流が流れることから、拡幅部材５を通じてノズル１の先端が冷えやすくなる。その結果、吐出時のポリマー溶融粘度が上昇することで、繊維を効率よく延伸することが阻害され細径化の効果が低減してしまうおそれがある。そのため拡幅壁面６の加熱機構を設け、ポリマーの吐出時の溶融粘度上昇を防ぐことが好ましい。ヒーターの種類については、棒状でもプレート状などが挙げられるが、均一性の観点からプレート状がより好ましい。ヒーターの熱量については、１．２ＫＷ／ｍ以上であることが好ましい。また、加熱機構の代わりに、拡幅部材の表面が熱伝導率の低い断熱板で覆われていても良く、熱伝導率については、１．０Ｗ／ｍ／Ｋ以下であることが望ましい。 Also, in the present invention, it is preferable to have a heating mechanism for the widened wall surface 6 . Specifically, for example, it is desirable that the widening member 5 constituting the widening wall surface 6 is heated by a heating mechanism such as a heater. In the present invention, for example, a normal temperature accompanying flow flows along the widened wall surface 6 toward the nozzle 1 , so that the tip of the nozzle 1 is easily cooled through the widened member 5 . As a result, the melt viscosity of the polymer at the time of ejection increases, which hinders the efficient drawing of the fiber and may reduce the effect of reducing the diameter. Therefore, it is preferable to provide a heating mechanism for the widened wall surface 6 to prevent the melt viscosity from increasing during ejection of the polymer. As for the type of heater, a rod-shaped heater, a plate-shaped heater, and the like can be used, and a plate-shaped heater is more preferable from the viewpoint of uniformity. The heat quantity of the heater is preferably 1.2 KW/m or more. Further, instead of the heating mechanism, the surface of the widening member may be covered with a heat insulating plate having a low thermal conductivity, and the thermal conductivity is desirably 1.0 W/m/K or less.
　さらに本発明においては、図８に示すように、リップ３下面近傍において、拡幅壁面６が平面部に加えてリップ３下面に漸近するＲ部を有する構成であってもよい。本発明では、前述の通り、口金直下でのエアの噴流部の拡幅を、拡幅壁面６に沿わせた随伴流の流入により抑えることがポイントであることから、随伴流の主な流れに影響が無い範囲でＲ部を形成したとしても、細径化の効果が発現する。 Further, in the present invention, as shown in FIG. 8, in the vicinity of the lower surface of the lip 3, the widened wall surface 6 may have an R portion that asymptotically approaches the lower surface of the lip 3 in addition to the flat portion. In the present invention, as described above, the main point of the present invention is to suppress the expansion of the air jet portion directly under the mouthpiece by the inflow of the accompanying flow along the widening wall surface 6, so that the main flow of the accompanying flow is not affected. Even if the R portion is formed within a range in which there is no R portion, the effect of reducing the diameter is exhibited.
　本発明において、拡幅壁面は、算術平均粗さＲａが１００μｍ以下であることが好ましい。拡幅壁面の算術平均粗さＲａがＲａ＞１００μｍの場合には、拡幅壁面６の凹凸によって渦流が発生しやすく、随伴流の乱れが大きくなり、細径化の効果が低減するおそれがある。また、拡幅壁面６の加工による節目の方向は、図５に示す拡幅壁面６近傍の気流の向きに対して平行であることが、渦流の発生を抑制できるため好ましい。 In the present invention, the widened wall surface preferably has an arithmetic mean roughness Ra of 100 μm or less. If the arithmetic mean roughness Ra of the widened wall surface is Ra>100 μm, the unevenness of the widened wall surface 6 tends to generate eddy currents, resulting in increased turbulence in the entraining flow, which may reduce the effect of reducing the diameter. Moreover, it is preferable that the direction of the knot formed by machining the widened wall surface 6 is parallel to the direction of the airflow near the widened wall surface 6 shown in FIG.
　本発明で用いる拡幅部材の材質としては、ステンレスやアルミ等の金属材料やガラス繊維等のプラスチック材料を好ましく用いることができる。 Metal materials such as stainless steel and aluminum, and plastic materials such as glass fiber can be preferably used as materials for the widening member used in the present invention.
　本発明は極めて汎用性の高い発明であり、公知のメルトブロー不織布を製造するにあたり適用できる。従って、不織布を構成するポリマーにより特に限られるものではない。例えば、不織布を構成するポリマーの一例を挙げれば、ポリエステル、ポリアミド、ポリフェニレンサルファイド、ポリエチレン、ポリプロピレン等々が挙げられる。ポリマーのＭＦＲ（メルトフローレート）は、３００～１５００ｇ／１０分であることが好ましく、特に、９００～１３００ｇ／１０分であることが好ましい。上記したポリマーに、製糸安定性を損なわない範囲で、二酸化チタン等の艶消し剤、酸化ケイ素、カリオン、着色防止剤、安定剤、抗酸化剤、消臭剤、難燃剤、糸摩擦低減剤、着色顔料、表面改質剤等の各種機能性粒子や有機化合物の添加剤が含有されていてもよく、共重合が含まれても良い。また、セルロース、ポリスルホン、ポリエーテルイミド、ポリアクリルニトリル等のポリマーを溶媒に溶解させたポリマー溶液であってもよい。ポリマーの紡糸温度は、使用するポリマーの融点が目安となり、融点＋６０℃以下で設定するのが望ましい。 The present invention is an invention with extremely high versatility, and can be applied to the production of known melt-blown nonwoven fabrics. Therefore, the polymer constituting the nonwoven fabric is not particularly limited. For example, polyesters, polyamides, polyphenylene sulfides, polyethylenes, polypropylenes, and the like can be cited as examples of polymers that constitute nonwoven fabrics. The MFR (melt flow rate) of the polymer is preferably 300-1500 g/10 min, more preferably 900-1300 g/10 min. Matting agents such as titanium dioxide, silicon oxide, carion, anti-coloring agents, stabilizers, antioxidants, deodorants, flame retardants, yarn friction reducing agents, and Various functional particles such as coloring pigments and surface modifiers and additives of organic compounds may be contained, and copolymerization may be included. Alternatively, a polymer solution obtained by dissolving a polymer such as cellulose, polysulfone, polyetherimide, or polyacrylonitrile in a solvent may be used. The melting point of the polymer used serves as a guideline for the spinning temperature of the polymer, and it is desirable to set the melting point +60° C. or lower.
　本発明において、ギャップ４より吹き付ける気体は、空気が最も経済的で好ましいが、混合ガスやスチーム、飽和蒸気、過熱蒸気であってもよい。牽引力を向上させるには、前述の式（Ａ）の通り、気体の密度ρも関連していることから、密度が高い気体を選択することが好ましい。気体の温度は、吐出されるポリマー温度から＋５０℃以下の範囲で設定するのが良い。 In the present invention, air is the most economical and preferable gas to be blown from the gap 4, but mixed gas, steam, saturated steam, and superheated steam may also be used. In order to improve the tractive force, it is preferable to select a gas with a high density because the density ρ of the gas is also related as shown in the above formula (A). The temperature of the gas is preferably set within a range of +50° C. or less from the temperature of the discharged polymer.
　また本発明においては、左右のギャップ４から供給される気体の流量に差があっても良い。 Also, in the present invention, there may be a difference in the flow rate of the gas supplied from the left and right gaps 4.
　以下、実施例を挙げて、本発明の製造装置と製造方法の効果を具体的に説明する。なお実施例における特性値の測定法等は次の通りである。 The effects of the manufacturing apparatus and manufacturing method of the present invention will be specifically described below with reference to examples. Methods for measuring characteristic values in the examples are as follows.
　＜気流の偏り＞
　気流の偏りは、紡糸中に、風速計（日本カノマックス株式会社：ＭＯＤＥＬ６５０１シリーズ）を用いて、装置幅の中央の位置で評価する。具体的には、左右の拡幅壁面に対して、ノズル吐出面からポリマー吐出方向に１０ｍｍ下流側の位置で、かつ、拡幅壁面から２ｍｍ内側の位置に、風速計のプローブを設置し、１秒ごとに風速を測定し、１０秒間の平均値を用いる。得られた風速値について、左右の壁面で５倍以上の差がついていた場合、気流の偏りがあると判断する。 <Misalignment of airflow>
The deviation of the airflow is evaluated at the center position of the apparatus width during spinning using an anemometer (Japan Kanomax Co., Ltd.: MODEL6501 series). Specifically, an anemometer probe was installed at a position 10 mm downstream from the nozzle ejection surface in the direction of polymer ejection from the left and right widened wall surfaces and at a position 2 mm inward from the widened wall surface. Measure the wind speed at 10 seconds and use the average value for 10 seconds. If there is a difference of 5 times or more between the obtained wind speed values on the left and right wall surfaces, it is determined that the airflow is biased.
　＜平均繊維径＞
　捕集ネットコンベア上に捕集して得た不織布から、幅方向中央５０ｍｍ以外を除いたうえで、ランダムに小片サンプルを採取する。電子顕微鏡で各小片サンプルの写真を撮影し、その中の１００本を無作為に抽出して繊維径を測定し、算術平均値を求める。 <Average fiber diameter>
From the non-woven fabric obtained by collecting on the collection net conveyor, a small piece sample is randomly collected after removing the non-woven fabric other than 50 mm in the width direction center. A photograph of each small piece sample is taken with an electron microscope, 100 of them are randomly selected, the fiber diameter is measured, and the arithmetic mean value is obtained.
　（比較例１）
　図２に示すようなメルトブロー口金（すなわちリップ下面側の拡幅壁面なし）を用い、不織布の製造を行った。原料樹脂として、ＡＳＴＭ－Ｄ１２３８に準拠し、おもり２．１６Ｋｇ、温度２３０℃でのメルトフローレートが１１００ｇ／１０分のポリプロピレン樹脂を用い、溶融樹脂温度２８０℃、ノズル孔数１５０個、ノズル吐出孔のピッチ１ｍｍ、ノズル孔径０．４ｍｍ、単孔吐出量０．１ｇ／ｍiｎ、リップ下面における、熱風を供給するギャップ幅１．５ｍｍ、熱風流量５６０Ｎｍ３／（ｈｒ・ｍ）、リップ下面とポリマー吐出方向が成す角度９０°（β＝９０°）として、表１に示す条件で、不織布の製造を行った。試験結果を表１に示す。比較例１では、不織布をコンベアベルト上に捕集することができ、平均繊維径は１．１μｍだった。 (Comparative example 1)
A non-woven fabric was produced using a melt-blown nozzle as shown in FIG. As the raw material resin, a polypropylene resin conforming to ASTM-D1238 with a weight of 2.16 kg and a melt flow rate of 1100 g/10 minutes at a temperature of 230°C is used. 1 mm pitch, nozzle hole diameter 0.4 mm, single hole discharge rate 0.1 g/min, gap width for supplying hot air on the lower surface of the lip 1.5 mm, hot air flow rate 560 Nm 3 /(hr m), lip lower surface and polymer discharge A nonwoven fabric was produced under the conditions shown in Table 1 with an angle formed by the directions of 90° (β = 90°). Table 1 shows the test results. In Comparative Example 1, the nonwoven fabric could be collected on the conveyor belt, and the average fiber diameter was 1.1 μm.
　（実施例１～１０、比較例２～６）
　図１に示すようなメルトブロー口金（すなわちリップ下面側の拡幅壁面あり）を用い、不織布の製造を行った。原料樹脂として、ＡＳＴＭ－Ｄ１２３８に準拠し、おもり２．１６Ｋｇ、温度２３０℃でのメルトフローレートが１１００ｇ／１０分のポリプロピレン樹脂を用い、溶融樹脂温度２８０℃、ノズル孔数１５０個、ノズル吐出孔のピッチ１ｍｍ、ノズル孔径０．４ｍｍ、単孔吐出量０．１ｇ／ｍiｎ、リップ下面における、熱風を供給するギャップ幅１．５ｍｍ、熱風流量５６０Ｎｍ３／(ｈｒ・ｍ)、ヒーターによる拡幅部材の加熱はなし、として、表２～４に示す条件で、不織布の製造を行った。試験結果を表２～４に示す。 (Examples 1 to 10, Comparative Examples 2 to 6)
A nonwoven fabric was produced using a melt-blown nozzle (that is, with a widened wall surface on the lower surface side of the lip) as shown in FIG. As the raw material resin, a polypropylene resin conforming to ASTM-D1238 with a weight of 2.16 kg and a melt flow rate of 1100 g/10 minutes at a temperature of 230°C is used. 1 mm pitch, nozzle hole diameter 0.4 mm, single hole discharge rate 0.1 g / min, gap width for supplying hot air on the lower surface of the lip 1.5 mm, hot air flow rate 560 Nm 3 / (hr m), width expansion member by heater A nonwoven fabric was produced under the conditions shown in Tables 2 to 4 without heating. Test results are shown in Tables 2-4.
　対向する拡幅壁面のなす角度αが６０°から１２０°の範囲で、かつ、交点Ｘ間の間隔Ｐと交点Ｙ間の間隔Ｈとの比率Ｈ／Ｐが２から１５の範囲であった実施例１～１０においては、いずれにおいても、口金直下の噴流を制御することができ、安定的に極細繊維の不織布を製造することができた。実施例６、８では、時折、拡幅壁面に樹脂が堆積される様子が観察されたため、定期的に付着したポリマーを除去する必要があったが、安定的な不織布の連続製造に支障をきたすことはなかった。 An embodiment in which the angle α formed by the opposing widened wall surfaces is in the range of 60° to 120°, and the ratio H/P of the interval P between the intersection points X and the interval H between the intersection points Y is in the range of 2 to 15. In any of 1 to 10, it was possible to control the jet just below the spinneret, and it was possible to stably produce a nonwoven fabric of ultrafine fibers. In Examples 6 and 8, it was observed that the resin was occasionally deposited on the widened wall surface, so it was necessary to periodically remove the adhering polymer. There was no.
　一方、比較例２では、対向する拡幅壁面が成す角度αを５０°、交点Ｘ間の間隔Ｐと、交点Ｙ間の間隔Ｈとの比率Ｈ／Ｐを１に変更する以外は実施例２と同様にして不織布の製造を試みたところ、一方の壁面に気流が沿って流れてしまい、不織布をコンベアベルト上に捕集することが出来なかった
　比較例３では、対向する拡幅壁面が成す角度αを５０°に変更する以外は実施例２と同様にして、不織布の製造を試みたが、一方の壁面に気流が沿って流れて、不織布をコンベアベルト上に捕集することが出来なかった。 On the other hand, Comparative Example 2 is the same as Example 2 except that the angle α formed by the opposing widened wall surfaces is changed to 50°, and the ratio H/P between the interval P between the intersection points X and the interval H between the intersection points Y is changed to 1. When an attempt was made to produce a nonwoven fabric in the same manner, the airflow flowed along one wall surface, and the nonwoven fabric could not be collected on the conveyor belt. A nonwoven fabric was produced in the same manner as in Example 2 except that the angle was changed to 50°, but the airflow flowed along one wall surface and the nonwoven fabric could not be collected on the conveyor belt.
　比較例４では、交点Ｘ間の間隔Ｐと、交点Ｙ間の間隔Ｈとの比率Ｈ／Ｐを１に変更する以外は実施例２と同様にして不織布の製造を試みたが、一方の壁面に気流が沿って流れて、不織布をコンベアベルト上に捕集することが出来なかった。 In Comparative Example 4, an attempt was made to produce a nonwoven fabric in the same manner as in Example 2, except that the ratio H/P between the spacing P between the intersection points X and the spacing H between the intersection points Y was changed to 1. The nonwoven fabric could not be collected on the conveyor belt because the air flow flowed along with the nonwoven fabric.
　比較例５では、交点Ｘ間の間隔Ｐと、交点Ｙ間の間隔Ｈとの比率Ｈ／Ｐを２１に変更する以外は実施例２と同様にして不織布の製造を試みたところ、不織布を得ることができたものの、随伴流が噴出した気流を狭めることができず、細径化の効果が得られない結果となった。 In Comparative Example 5, an attempt was made to produce a nonwoven fabric in the same manner as in Example 2, except that the ratio H/P between the spacing P between the intersection points X and the spacing H between the intersection points Y was changed to 21. As a result, a nonwoven fabric was obtained. However, it was not possible to narrow the airflow spouted by the accompanying flow, resulting in a result that the effect of reducing the diameter could not be obtained.
　比較例６では、対向する拡幅壁面が成す角度αを１５０°に変更する以外は実施例４と同様にして不織布の製造を試みたところ、不織布を得ることができたものの、随伴流が噴出した気流を狭めることができず、細径化の効果が得られない結果となった。 In Comparative Example 6, an attempt was made to produce a nonwoven fabric in the same manner as in Example 4, except that the angle α formed by the opposing widened wall surfaces was changed to 150°. As a result, the airflow could not be narrowed and the effect of reducing the diameter could not be obtained.
　（比較例７）
　図２に示すようなメルトブロー口金（すなわちリップ下面側の拡幅壁面なし）を用い、ギャップ幅０．５ｍｍ、熱風流量４５０Ｎｍ３／（ｈｒ・ｍ）、以外の条件は比較例１と同じ条件で、不織布の製造を行った。試験結果を表５に示す。比較例７では、不織布をコンベアベルト上に捕集することができ、平均繊維径は１．１μｍだった。 (Comparative Example 7)
Using a melt - blown nozzle as shown in FIG. Non-woven fabric was manufactured. Table 5 shows the test results. In Comparative Example 7, the nonwoven fabric could be collected on the conveyor belt, and the average fiber diameter was 1.1 μm.
　（実施例１１～１３、比較例８、９）
　図１に示すようなメルトブロー口金（すなわちリップ下面側の拡幅壁面あり）を用い、ギャップ幅０．５ｍｍ、熱風流量４５０Ｎｍ３／（ｈｒ・ｍ）、対向する壁面が成す角度αを９０°、リップ下面とポリマー吐出方向が成す角度βを９０°、拡幅壁面のポリマー吐出方向の長さγを３０ｍｍ、拡幅壁面の算術平均粗さＲａを１２．５μｍ、ヒーターによる拡幅部材の加熱はなし、として、表５に示す条件で不織布の製造を行った。 (Examples 11 to 13, Comparative Examples 8 and 9)
Using a melt - blown nozzle as shown in FIG. The angle β formed by the lower surface and the polymer ejection direction is 90°, the length γ of the widened wall surface in the polymer ejection direction is 30 mm, the arithmetic mean roughness Ra of the widened wall surface is 12.5 μm, and the widened member is not heated by a heater. A nonwoven fabric was produced under the conditions shown in 5.
　交点Ｘ間の間隔Ｐと交点Ｙ間の間隔Ｈとの比率Ｈ／Ｐが２から１５の範囲であった実施例１１～１３においては、いずれにおいても、口金直下の噴流を制御することができ、安定的に極細繊維の不織布を製造することができた。 In Examples 11 to 13, in which the ratio H/P between the interval P between the intersection points X and the interval H between the intersection points Y was in the range of 2 to 15, the jet directly below the nozzle could be controlled. , it was possible to stably produce a nonwoven fabric of ultrafine fibers.
　比較例８では、交点Ｘ間の間隔Ｐと、交点Ｙ間の間隔Ｈとの比率Ｈ／Ｐを１に変更する以外は実施例１１と同様にして不織布の製造を試みたが、一方の壁面に気流が沿って流れて、不織布をコンベアベルト上に捕集することが出来なかった。 In Comparative Example 8, an attempt was made to produce a nonwoven fabric in the same manner as in Example 11, except that the ratio H/P between the spacing P between the intersection points X and the spacing H between the intersection points Y was changed to 1. The nonwoven fabric could not be collected on the conveyor belt because the air flow flowed along with the nonwoven fabric.
　比較例９では、交点Ｘ間の間隔Ｐと、交点Ｙ間の間隔Ｈとの比率Ｈ／Ｐを２５に変更する以外は実施例１１と同様にして不織布の製造を試みたところ、不織布を得ることができたものの、随伴流が噴出した気流を狭めることができず、細径化の効果が得られない結果となった。 In Comparative Example 9, an attempt was made to produce a nonwoven fabric in the same manner as in Example 11, except that the ratio H/P between the spacing P between the intersection points X and the spacing H between the intersection points Y was changed to 25. As a result, a nonwoven fabric was obtained. However, it was not possible to narrow the airflow spouted by the accompanying flow, resulting in a result that the effect of reducing the diameter could not be obtained.
　（実施例１４）
　図１に示すようなメルトブロー口金（すなわちリップ下面側の拡幅壁面あり）を用い、ギャップ幅０．５ｍｍ、熱風流量４５０Ｎｍ３／（ｈｒ・ｍ）、対向する壁面が成す角度αを９０°、リップ下面とポリマー吐出方向が成す角度βを９０°、拡幅壁面のポリマー吐出方向の長さγを３０ｍｍ、拡幅壁面の算術平均粗さＲａを１２．５μｍ、プレート状のヒーターを用いて拡幅部材を２．０ＫＷ／ｍで加熱（加熱面：拡幅壁面の逆側面）して、表５に示す条件で不織布の製造を行った。 (Example 14)
Using a melt - blown nozzle as shown in FIG. The angle β between the lower surface and the direction of polymer ejection is 90°, the length γ of the widened wall surface in the direction of polymer ejection is 30 mm, the arithmetic average roughness Ra of the widened wall surface is 12.5 μm, and the widened member is divided into two parts using a plate-shaped heater. A nonwoven fabric was produced under the conditions shown in Table 5 by heating at 0 KW/m (heating surface: opposite side of the widened wall surface).
　拡幅部材を加熱しなかった実施例１２に比べ、さらに極細の繊維からなる不織布を安定的に製造することができた。 Compared to Example 12 in which the widening member was not heated, a nonwoven fabric made of finer fibers could be stably produced.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　本発明の製造装置・製造方法による不織布は、工業資材用フィルター、オムツ、生理用品、医療用マスク、医療用ガウン、花粉ガードマスク、ドレープといった衛生材料、自動車用資材、液体濾過用フィルター、合紙、洗車ブラシといった産業資材、食品包装材、ふろしき、テープヤーン、靴資材、カイロ、ティーバッグ、クリーニングカバーといった生活資材、べたがけ、農資ポットといった農業資材、屋根元材、土木安定シート、断熱材手段材、床材、ハウスラップといった建材、土木資材などに応用できるが、その応用範囲がこれらに限られるものでない。 The non-woven fabric produced by the production apparatus and production method of the present invention can be used for industrial material filters, diapers, sanitary products, medical masks, medical gowns, pollen guard masks, sanitary materials such as drapes, automotive materials, liquid filtration filters, and interleaving paper. , car wash brushes and other industrial materials, food packaging materials, furoshiki cloth, tape yarn, shoe materials, daily life materials such as body warmers, tea bags, and cleaning covers, agricultural materials such as adhesives and agricultural material pots, roof materials, civil engineering stabilizing sheets, and heat insulating materials It can be applied to construction materials such as building materials, floor materials, house wraps, civil engineering materials, etc., but the scope of application is not limited to these.
１　　ノズル
２　　吐出孔
３　　リップ
４　　ギャップ
５　　拡幅部材
６　　拡幅壁面
７　　吐出後の主なポリマーの軌跡
８　　ポリマー導入管
９　　メルトブロー口金
１０　捕集ネットコンベア
１１　ローラー
１２　ウエブ
１３　噴流部と噴流部でない領域の境界
Ｘ　　リップの下面とギャップを形成する壁面の交点
Ｙ　　リップの下面と拡幅壁面の交点
α　　対向する拡幅壁面が成す角度
β　　リップの下面とポリマー吐出方向が成す角度
γ　　拡幅壁面のポリマー吐出方向の長さ
ｌ　　延伸区間の長さ
ｗ　　噴流幅
Ｈ　　吐出孔を挟んで対向する交点Ｙ間の間隔
Ｐ　　吐出孔を挟んで対向する交点Ｘ間の間隔 1 Nozzle 2 Discharge hole 3 Lip 4 Gap 5 Widening member 6 Widening wall surface 7 Main trajectory of polymer after discharge 8 Polymer introduction pipe 9 Melt blow nozzle 10 Collection net conveyor 11 Roller 12 Web 13 Boundary between jet part and non-jet part X: Intersection point of the lower surface of the lip and the wall surface forming the gap Y Intersection point of the lower surface of the lip and the widened wall surface α Angle formed by the opposed widened wall surfaces β Angle formed by the lower surface of the lip and the direction of polymer discharge γ Length of the widened wall surface in the direction of polymer discharge l Length of stretched section w Jet width H Distance between intersection points Y facing each other across the discharge hole P Distance between intersection points X facing each other across the discharge hole

Claims (7)

  1. 　溶融したポリマーを吐出するための吐出孔が１列に配された吐出孔群を有するノズルと、前記ノズルの吐出孔群を挟んで対向するように配された一対のリップとの間に、スリット状のギャップを有し、前記吐出孔より吐出したポリマーに対して前記ギャップから気体を吹き付けて不織布を製造する装置であって、
    前記吐出孔より吐出されるポリマーを挟んで対向するように、前記リップの下面を起点に、ポリマー吐出方向に延在する一対の拡幅壁面を配し、
    前記一対の拡幅壁面の成す角度αが６０°≦α≦１２０°の範囲であり、且つ、
    前記リップの下面と前記ギャップを形成する壁面の交点をＸ、前記リップの下面と前記拡幅壁面の交点をＹとしたとき、対向する交点Ｘ間の間隔Ｐと、対向する交点Ｙ間の間隔Ｈとが、２≦Ｈ／Ｐ≦１５の範囲である
    ことを特徴とする不織布の製造装置。     A slit is provided between a nozzle having a group of discharge holes arranged in a row for discharging a molten polymer and a pair of lips arranged to face each other with the group of discharge holes of the nozzle interposed therebetween. A device for manufacturing a nonwoven fabric by blowing gas from the gap against the polymer discharged from the discharge hole,
    a pair of widened wall surfaces extending in the direction of polymer discharge from the lower surface of the lip so as to face each other across the polymer discharged from the discharge hole;
    The angle α formed by the pair of widening wall surfaces is in the range of 60°≦α≦120°, and
    When the intersection of the lower surface of the lip and the wall surface forming the gap is X, and the intersection of the lower surface of the lip and the widened wall surface is Y, the distance P between the opposing intersections X and the distance H between the opposing intersections Y is in the range of 2≦H/P≦15.
  2. 　前記リップの下面とポリマー吐出方向との成す角度βが、７０°≦β≦１２０°である、請求項１に記載の不織布の製造装置。 The apparatus for manufacturing a nonwoven fabric according to claim 1, wherein the angle β between the lower surface of the lip and the direction of polymer discharge is 70°≦β≦120°.
  3. 　前記拡幅壁面のポリマー吐出方向の長さγが１０ｍｍ以上である、請求項１または２に記載の不織布の製造装置。 The nonwoven fabric production apparatus according to claim 1 or 2, wherein the length γ of the widened wall surface in the direction of polymer discharge is 10 mm or more.
  4. 　前記拡幅壁面がポリマー吐出方向と交差する方向に移動可能である、請求項１～３のいずれかに記載の不織布の製造装置。 The apparatus for manufacturing a nonwoven fabric according to any one of claims 1 to 3, wherein the widened wall surface is movable in a direction intersecting the direction of polymer ejection.
  5. 　前記拡幅壁面の算術平均粗さＲａが１００μｍ以下である、請求項１～４のいずれかに記載の不織布の製造装置。 The apparatus for manufacturing a nonwoven fabric according to any one of claims 1 to 4, wherein the widened wall surface has an arithmetic mean roughness Ra of 100 µm or less.
  6. 前記拡幅壁面の加熱機構を有している、請求項１～５のいずれかに記載の不織布の製造装置。 The nonwoven fabric manufacturing apparatus according to any one of claims 1 to 5, further comprising a heating mechanism for the widened wall surface.
  7. 　請求項１～６のいずれかの装置を用いた不織布の製造方法。 A method for manufacturing a nonwoven fabric using the apparatus according to any one of claims 1 to 6.
PCT/JP2022/025714 2021-07-27 2022-06-28 Nonwoven production device and production method WO2023008052A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
CN202280042289.6A CN117500963A (en) 2021-07-27 2022-06-28 Apparatus and method for producing nonwoven fabric
KR1020247000325A KR20240035437A (en) 2021-07-27 2022-06-28 Manufacturing device and manufacturing method of nonwoven fabric
JP2022542335A JP7168135B1 (en) 2021-07-27 2022-06-28 NONWOVEN FABRIC MANUFACTURING APPARATUS AND MANUFACTURING METHOD

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5167411A (en) * 1974-12-09 1976-06-11 Asahi Chemical Ind
US6247911B1 (en) * 1999-05-20 2001-06-19 The University Of Tennessee Research Corporation Melt blowing die
JP2003502524A (en) * 1999-06-21 2003-01-21 キンバリー クラーク ワールドワイド インコーポレイテッド Die assembly for melt blow device
US20080122143A1 (en) * 2006-11-28 2008-05-29 Herman Peter K Apparatus, system, and method for maximizing ultrafine meltblown fiber attenuation

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5167411A (en) * 1974-12-09 1976-06-11 Asahi Chemical Ind
US6247911B1 (en) * 1999-05-20 2001-06-19 The University Of Tennessee Research Corporation Melt blowing die
JP2003502524A (en) * 1999-06-21 2003-01-21 キンバリー クラーク ワールドワイド インコーポレイテッド Die assembly for melt blow device
US20080122143A1 (en) * 2006-11-28 2008-05-29 Herman Peter K Apparatus, system, and method for maximizing ultrafine meltblown fiber attenuation

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