JP2020073749A - Spun-bonded non-woven fabric - Google Patents

Abstract

To improve uniformity of a spun-bonded non-woven fabric.SOLUTION: A diffusion part 20 includes an injection nozzle 34, a diffusion space 36 is provided between the injection nozzle 34 and a mobile zone 32 of a capturing part 18, and a sub-nozzle 40 for jetting air is provided with an opening 40A arranged so as to be aligned with an opening 34A of the injection nozzle 34. The injection nozzle 34 injects a plurality of filaments toward the mobile zone 32 together with air, and the sub-nozzle 40 injects air at a flow rate 1/2 or less and 1/10 or more of a flow rate of the air of the injection nozzle 34. The air injected from the injection nozzle 34 forms a transfer flow flowing in the diffusion space 36 so as to gradually expand, and the plurality of filaments are transferred toward the mobile zone 32 by the transfer flow while being diffused, and are captured. In addition, the air injected from the sub-nozzle 40 flows through a boundary layer of the conveyance flow, and prevents the air in the diffusion space from entering into the transfer flow.SELECTED DRAWING: Figure 2

Description

  The present invention relates to spunbond nonwoven fabrics.

  Nonwoven fabrics such as spunbonded nonwoven fabrics are widely used in medical, sanitary, civil engineering and packaging materials. Spunbonded non-woven fabrics should be collected and deposited while being diffused on a collection medium after cooling the filaments that have been melt-spun with a thermoplastic resin using cooling air and stretching with drawing air. Manufactured from the web obtained in.

  In Patent Document 1, a cross section in the horizontal direction has a rectangular shape, and the cross section is gradually reduced in the filament running direction. A cooling chamber is connected to the cooling chamber, and a stepped recess is formed in the wall at the discharge port. An apparatus for producing spun fiber strips from aerodynamically stretched synthetic resin filaments is disclosed that has a stretching nozzle and a fiber placement device connected to the stretching nozzle. The fiber placement device of Patent Document 1 has a rectangular cross section in the horizontal direction, has the form of a jet pump having a venturi annular flow region in the vertical direction, and a diffuser outlet. The amount of air sucked from the free air suction port is adjusted by the suction pipe facing the diffuser outlet with the filter belt interposed therebetween.

  Patent Document 2 has a nozzle plate having a large number of nozzles, a processing shaft, a transport unit and a transport conveyor, processing air flows into the processing shaft and the transport unit, and endless fibers flow from nozzle holes of the nozzle plate. And is introduced into the processing shaft by the discharge movement towards the conveyor as an endless fiber group in the form of a mixture of air and fibers, the carrier unit extending to the central inlet conduit for the endless fiber group and then to the conveyor conveyor. An apparatus for producing a spin fleece web from thermoplastic resin endless fibers, comprising a diffuser conduit for discharging a forced discharge motion and a fleece forming motion overlapping therewith, both conduits extending in a direction transverse to the traveling direction of a conveyor belt. Is disclosed. In this document, an inlet conduit and / or a diffuser conduit is used for the mixing of air and fibers, a flow for the additional introduction of air into the conduit extending across the width of the conduit and across the direction of travel of the conveyor belt. An aerodynamic equalizing device in the form of a slit and in the form of an outflow slit for expelling air from the conduit, additionally with a flow rate to be additionally fed and a flow rate to be let out It is controlled or adjusted for the purpose of affecting the even distribution of the fibers therein. Further, in Patent Document 2, the inner surface of the inflow conduit and / or the diffuser conduit is provided with an obstacle member in the vicinity of the surface in the vertical section of the conduit, and a spiral region is formed rearward with respect to the flow direction thereof.

  In Patent Document 3, a spinneret for forming filaments is provided as an apparatus for producing a spunbond formed from filaments, and a cooling chamber for supplying process air for cooling the filaments is provided downstream of the spinneret. A stretching unit is connected to the cooling chamber, the connection region between the cooling chamber and the stretching unit is closed, and the stretching unit is configured such that the passage wall is branched over at least part of the length of the stretching passage. In the draw unit, in a draw unit, additional air at the upstream end of the branch draw passage section is injected into the draw passage by the condition that the bundle of filaments is formed wide in the machine direction to deposit the filaments of the spunbond web. A device provided with is described. Further, in Patent Document 3, there is a description in which there is a deposition unit downstream of the drawing unit, the deposition unit is composed of an upstream diffuser and an adjacent downstream diffuser, and an ambient air inlet slit is provided between the upstream diffuser and the downstream diffuser. There is.

Patent No. 2556953 Japanese Patent No. 3135498 Patent No. 5094588

  By the way, uniformity and strength are important properties relating to the quality of the nonwoven fabric. For example, Patent Document 2 aims to obtain a nonwoven fabric having a uniform mesh size. However, in a highly uniform nonwoven fabric, the entanglement of filaments may be insufficient and the strength may be reduced.

  The present invention has been made in view of the above facts, and an object of the present invention is to provide a spunbonded non-woven fabric in which the reduction in strength is suppressed and the uniformity is improved.

Specific means for achieving the above object include the following aspects.
In the spunbonded nonwoven fabric of the first aspect, the ratio of the strength at 5% elongation in the machine direction to the strength at 5% elongation in the direction perpendicular to the machine direction is 2.0 or less, and the areal variation is 3.0% or less. Is a spunbond nonwoven fabric.

  The spunbonded nonwoven fabric according to the second aspect is the spunbonded nonwoven fabric according to the first aspect, wherein the maximum strength when stretched in the machine direction is 35.0 (N / 25 mm) or more.

  In the production of the spunbonded nonwoven fabric according to the first aspect and the second aspect, a filament is spun from a molten resin or the like, and a spinning section (spinning step) for leading out a plurality of filaments is introduced from the spinning section. A cooling unit (cooling process) for cooling a plurality of filaments with a cooling air, a stretching unit (drawing process) for stretching a cooled plurality of filaments with a stretching air, and a plurality of stretched filaments are collected and deposited to form a web. A non-woven fabric is manufactured from the collected web, including a collecting portion (collecting step) to be generated. Further, the manufacturing apparatus may include a diffusing unit (diffusing step) for ejecting the filaments introduced from the drawing unit toward the collecting unit while diffusing the filaments.

  The diffusion unit includes a main nozzle and a diffusion space provided between the main nozzle and the collection medium of the collection unit. It is preferable that the diffusion space in the first and second aspects is a space that can naturally diffuse without hindering the diffusion of the air flow caused by the air ejected from the main nozzle. The diffusion space may be surrounded by a partition wall, but when surrounded by a partition wall, the partition wall may be provided apart from the air flow so as not to affect the air flow caused by the air ejected from the main nozzles. Further, a plurality of filaments are arranged along the machine width direction, and the main nozzle has a slit shape that is long along the machine width direction.

  As a result, the air ejected from the main nozzle becomes an air flow (jet flow) that flows toward the collection medium while gradually expanding in the diffusion space along the machine direction. The plurality of filaments ejected from the main nozzle together with air are diffused in the machine direction by the air flow formed in the diffusion space and collected in the collection medium.

  Here, the diffusing section is provided with an air flow generation unit, and the air flow generation unit generates an air flow in the vicinity of the air flow due to the air ejected from the main nozzle and is close to the air flow of the main nozzle. The air flow along the horizontal direction suppresses the air (air) in the diffusion space from entering the air flow due to the air ejected from the main nozzle together with the plurality of filaments. The airflow of the air ejected from the main nozzle has a flow velocity fluctuation inside, but when the air in the diffusion space enters, there is a region where the flow velocity fluctuation becomes larger than the surroundings. On the other hand, the air in the diffusion space is allowed to enter into the air flow caused by the air ejected from the main nozzle by generating an air flow in the vicinity of the air flow caused by the air ejected from the main nozzle. The region where the flow velocity fluctuation is suppressed and is larger than the surrounding region is narrowed, or the magnitude of the flow velocity fluctuation in the region where the flow velocity fluctuation is larger than the surrounding region is suppressed.

  In each filament, a region where the flow velocity fluctuation is larger than the surroundings is generated, and the greater the flow velocity fluctuation in the region is, the more the filaments are entangled with each other, and the filament bundle is generated, which deteriorates the uniformity. By suppressing the magnitude of the flow velocity fluctuation, the occurrence of filament bundles is suppressed and the uniformity is improved.

  Further, it is preferable that the air flow generation unit includes a sub nozzle that ejects air into the diffusion space. Further, the airflow generating means may include a sub nozzle having an opening arranged side by side with the opening of the main nozzle and ejecting air into the diffusion space.

  The airflow generating means includes a sub nozzle having an opening arranged side by side with the opening of the main nozzle, and the air ejected from the sub nozzle causes the air ejected from the main nozzle to be adjacent to the air flow around the air flow. Create an air flow.

  As a result, the air in the diffusion space is prevented from entering the air flow due to the air ejected from the main nozzles, so that the uniformity of the spunbonded nonwoven fabric can be easily improved.

  Further, the sub nozzle may be provided on the machine direction side of the main nozzle and on the side opposite to the machine direction.

  The sub nozzle may be provided on each of the machine direction side and the machine direction side with respect to the main nozzle. As a result, the air in the diffusion space is suppressed from entering the air flow of the air ejected from the main nozzle from the machine direction side and the machine direction opposite side, respectively, and thus is ejected from the main nozzle. It is possible to effectively prevent the fluctuation of the flow velocity of the air from increasing.

As a result, as a spunbonded non-woven fabric in which the reduction in strength is suppressed and the uniformity is improved, the ratio of the strength at 5% elongation in the machine direction to the strength at 5% elongation in the direction perpendicular to the machine direction is 2. It is suitable for obtaining a spunbonded non-woven fabric having a density of 0 or less and a density variation of 3.0% or less.
Further, it is suitable for producing a spunbonded nonwoven fabric having a maximum strength of 35.0 (N / 25 mm) or more when stretched in the machine direction. Further, in the obtained spunbond nonwoven fabric, the maximum strength of the produced nonwoven fabric when stretched in the machine direction is more preferably 37.5 (N / 25 mm) or more, and further preferably 40.0 (N / 25 mm). ), And most preferably 42.5 (N / 25 mm).
Further, it is suitable for producing a spunbonded nonwoven fabric having a unit weight variation (%) of preferably 3.0% or less, more preferably 2.5% or less.

  According to the embodiments of the present specification, there is an effect that a spunbonded non-woven fabric having improved uniformity while suppressing a decrease in strength can be obtained.

It is a schematic block diagram of the manufacturing apparatus which concerns on this Embodiment. It is a schematic block diagram which shows a diffusion part. It is a distribution diagram showing an example of a simulation result of the flow velocity fluctuation in the present embodiment. It is a distribution diagram which shows an example of the simulation result of the flow velocity fluctuation in proportionality. 4 is a chart showing a comparison of manufacturing conditions and physical properties according to examples.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a main part of a nonwoven fabric manufacturing apparatus 10 according to the present embodiment. The manufacturing apparatus 10 according to the present embodiment is used for manufacturing a spunbond nonwoven fabric. In the following description, the MD (machine direction) direction indicates the machine direction (machine flow direction), and the UP direction indicates the upper side in the vertical direction. In the following description, a direction (direction perpendicular to the machine direction) orthogonal to each of the MD direction and the UP direction will be referred to as a CD (cross machine direction) direction (machine width direction, not shown).

  The manufacturing apparatus 10 includes a spinning unit 12 that spins a molten resin in which a thermoplastic resin used for a spunbonded nonwoven fabric is melted to generate filaments, a cooling unit 14 that cools the spun filaments, and a filament. A stretching unit 16 that performs stretching processing is provided. Further, the manufacturing apparatus 10 collects the cooled and drawn filaments, and collects the filaments to obtain a web to be a non-woven fabric, and ejects the plurality of filaments toward the collector 18 so as to diffuse the filaments. The diffusion unit 20 is provided.

  The spinning unit 12 includes a spinneret 22 in which a plurality of spinning nozzles are arranged, and a molten resin introducing pipe 24 is connected to the spinneret 22. The spinning unit 12 spins the molten resin introduced into the spinneret 22 through the molten resin introducing pipe 24 with a spinning nozzle to produce filaments. In addition, the spinning unit 12 draws out a plurality of filaments arranged in the CD direction by the spinneret 22 including a plurality of spinning nozzles. The cooling unit 14 includes a cooling chamber 26 into which a plurality of spun filaments are introduced, and a cooling air supply duct 28 is connected to the cooling chamber 26. The cooling unit 14 uses the air supplied from the cooling air supply duct 28 as cooling air and cools the plurality of filaments introduced into the cooling chamber 26 with the cooling air.

  The stretching portion 16 includes a stretching shaft 30 having an opening cross section that is long in the CD direction (front and back direction of the paper surface in FIG. 1) and short in the MD direction and extends in the vertical direction. In the drawing section 16, the drawing shaft 30 is connected to the cooling chamber 26, and a plurality of filaments are introduced from the cooling chamber 26 to the drawing shaft 30. The drawing part 16 draws out the cooling air introduced together with the plurality of filaments or the air supplied into the drawing shaft 30 separately from the cooling air as the drawing air while drawing the filaments introduced from the cooling part 14 by the drawing air. To do.

  The collecting unit 18 includes a moving zone 32 as a collecting medium formed of mesh or punching metal, and a suction unit (not shown) provided below the moving zone 32. Further, the diffusion unit 20 ejects the drawing wind introduced from the drawing shaft 30 or the air introduced separately from the drawing wind toward the moving zone 32 of the collecting unit 18. The collecting unit 18 collects the ejected filaments on the collecting surface 32A of the moving zone 32 while sucking the filaments with a suction unit to generate a web that becomes a nonwoven fabric. The spinning unit 12, the cooling unit 14, the drawing unit 16, and the collecting unit 18 of the manufacturing apparatus 10 generate a plurality of filaments by spinning a molten resin, perform a cooling and drawing process on the generated filaments, and A known configuration for collecting a plurality of filaments can be applied.

  FIG. 2 shows a schematic configuration of the diffusion unit 20 according to this embodiment. The diffusion unit 20 includes a jet nozzle 34 as a main nozzle. The ejection nozzle 34 has an opening 34 </ b> A at the tip as an opening serving as an ejection port formed in a slit shape elongated in the CD direction, and is directed onto the moving zone 32 of the collection unit 18. In addition, the jet nozzle 34 is connected to the drawing shaft 30 of the drawing unit 16 and a plurality of filaments subjected to the cooling drawing process are introduced. In addition, in the diffusion unit 20, air is introduced into the ejection nozzle 34 separately from the air by the drawing wind or the air of the drawing wind.

  The diffusion unit 20 ejects the air and the plurality of filaments introduced into the ejection nozzle 34 toward the moving zone 32 of the collection unit 18 from the opening 34A. The diffusion unit 20 sends the plurality of filaments ejected from the ejection nozzle 34 toward the collection unit 18 by the air flow of the air ejected from the ejection nozzle 34. Hereinafter, the air flow generated by the air ejected together with the plurality of filaments from the ejection nozzle 34 is referred to as a carrier flow.

  In the diffusion unit 20, a diffusion space 36 is provided between the ejection nozzle 34 and the collection surface 32A of the moving zone 32 of the collection unit 18, and the carrier flow directs the inside of the diffusion space 36 to the movement zone 32. Flowing. The diffusion space 36 is a space that is not provided with a wall surface or the like that restricts the flow of the carrier flow due to the air jetted from the jet nozzle 34. That is, the diffusion space 36 is a space in which the carrier flow ejected from the ejection nozzle 34 is not affected by structures such as the wall surface other than the collecting portion 18. The diffusion space may be partitioned by the partition wall as long as the partition wall is provided so as not to interfere with the flow of the air flow.

  As a result, in the diffusion section 20, the carrier flow of the air ejected from the ejection nozzle 34 flows in the diffusion space 36 while gradually (naturally) expanding in the MD direction and the direction opposite to the MD direction. Further, the flow velocity of the carrier flow gradually decreases as it approaches the moving zone 32. The plurality of filaments ejected from the ejection nozzle 34 are diffused in the MD direction and the direction opposite to the MD direction by spreading the carrier flow in the diffusion space 36. As a result, in the manufacturing apparatus 10, the filaments are diffused and collected in the predetermined collecting area on the collecting surface 32A of the moving zone 32.

  The manufacturing apparatus 10 determines the opening width and opening length of the ejection nozzle 34 according to the nonwoven fabric to be produced, the production speed of the nonwoven fabric, the width in the CD direction of the web produced by the filaments being collected by the collecting unit 18, and the like. The moving speed of the moving zone 32, the distance between the ejection nozzle 34 and the collecting surface 32A of the moving zone 32, and the like are defined. In the diffusion unit 20, the interval (height H) between the tip of the ejection nozzle 34 and the surface of the moving zone 32 of the collection unit 18 is set to be 0.1 m or more and less than 1 m. Is the height of the diffusion space 36.

  Further, in the manufacturing apparatus 10, the flow velocity of the air ejected from the ejection nozzle 34 or the air volume of the ejected air per unit time is set. In the following, the flow velocity of the air at the opening of the ejection nozzle 34 is defined as the flow velocity Vm of the carrier flow. It is written as. In the diffusion unit 20, the spread of the carrier flow in the diffusion space 36 changes according to the flow velocity Vm, and when the flow velocity Vm is high, the spread of the carrier flow is smaller than when the flow velocity Vm is low.

  Since the diffusion space 36 is provided in the diffusion unit 20, the carrier flow ejected from the ejection nozzle 34 reaches the moving zone 32 while gradually expanding mainly in the MD direction. In the following description, the region of the carrier flow in the diffusion space 36 is referred to as the carrier flow region 38. In FIG. 2, the transport basin 38 is virtually shown.

  As shown in FIGS. 1 and 2, the diffusion section 20 is provided with a sub-nozzle 40 as an air flow generating means. The sub-nozzle 40 is provided with a slit-shaped opening 40A that is long in the CD direction as an opening. In the diffusion unit 20, the sub nozzles 40 are arranged on the MD direction side of the ejection nozzle 34 and on the side opposite to the MD direction, and the opening 40A of the sub nozzle 40 is aligned with the opening 34A of the ejection nozzle 34.

  An air supply pipe 42 is connected to the sub nozzle 40, and the air supplied through the air supply pipe 42 is ejected from the opening 40A. The diffusing section 20 is provided with the sub nozzle 40 via the air supply pipe 42 so that the air flow of the air ejected from the sub nozzle 40 has a flow velocity Vs determined according to the flow velocity Vm of the carrier flow ejected from the ejection nozzle 34. The air supplied to the is controlled. In the diffusion unit 20, the sub nozzle 40 is provided so that the air ejection direction is substantially parallel to the air ejection direction from the ejection nozzle 34. Here, the flow velocity Vs is preferably equal to or lower than the flow velocity Vm (Vs ≦ Vm), and more preferably equal to or higher than 1/10 of the flow velocity Vm (Vs ≧ (Vm / 10). The supply of air to the sub nozzle 40 is controlled so that the flow velocity Vs becomes 1/2 of the flow velocity Vm (Vs = Vm / 2).

  In the present embodiment, the opening 34A of the jet nozzle 34 and the opening 40A of the sub nozzle 40 are arranged side by side, but the present invention is not limited to this, and one of the opening 34A of the jet nozzle 34 and the opening 40A of the sub nozzle 40 is provided. May be arranged with a step so as to be farther from the collection surface 32A of the moving zone 32 than the other.

  As a result, as shown in FIG. 2, in the diffusion unit 20, the air jetted from the sub-nozzle 40 is caused to generate an air flow around the carrier flow (the carrier flow region 38) in the diffusion space 36 in the vicinity of the carrier flow. ing. In FIG. 2, the airflow generated by the air ejected from the sub nozzle 40 is virtually shown as an airflow layer 44.

  In the manufacturing apparatus 10 configured as described above, the plurality of filaments spun from the molten resin, cooled, and stretched are introduced into the ejection nozzle 34 of the diffusion unit 20. Further, air (air of drawing air or air supplied separately from the drawing air) for generating a carrier flow is introduced into the jet nozzle 34.

  A diffusion space 36 is provided in the diffusion unit 20 between the ejection nozzle 34 and the moving zone 32 of the collection unit 18, and the air and the plurality of filaments introduced into the ejection nozzle 34 are opened by the opening of the ejection nozzle 34. It is jetted from 34A toward the diffusion space 36. As a result, the plurality of filaments are blown onto the moving zone 32 of the collecting unit 18 and are collected on the collecting surface 32A while being diffused by the carrier flow of the air ejected from the ejection nozzle 34.

  By the way, the sub-nozzle 40 is provided in the diffusion part 20 together with the ejection nozzle 34, and the sub-nozzle 40 ejects the air supplied through the air supply pipe 42 to the diffusion space 36. As a result, in the diffusion space 36, an air flow is generated around the transport flow in the vicinity of the transport flow, and the air in the diffusion space 36 is suppressed from entering the transport flow (the transport flow region 38).

  For the plurality of filaments transported in the diffusion space 36 by the transport flow, the flow velocity fluctuates inside the transport flow. In a region where the flow velocity fluctuation is larger than the surroundings, the larger the flow velocity fluctuation, the greater the throat filament entanglement. Become. As a result, the nonwoven fabric obtained from the web produced by collecting the filaments has high tensile strength. However, when the number of filaments entangled in the collected web is reduced, the uniformity of the nonwoven fabric is deteriorated.

  On the other hand, in the diffusion unit 20 provided with the sub nozzle 40, the air jetted from the sub nozzle 40 forms an air flow around the carrier flow in the vicinity of the carrier flow, and occurs inside the carrier flow. The magnitude of the flow velocity fluctuation can be suppressed in the region where the flow velocity fluctuation is large. As a result, in the web collected in the collection unit 18, the filament is prevented from being entangled more, and a nonwoven fabric with improved uniformity is obtained.

  Here, FIGS. 3A and 3B show simulation results of flow velocity fluctuations (velocity fluctuations) of the air flow in the diffusion space 36 by distribution of the flow velocity fluctuations. FIG. 3A corresponds to the diffusing section 20 of the present embodiment (hereinafter, Example 1) provided with the ejection nozzle 34 and the sub nozzle 40, and FIG. 3B is a sub nozzle which is to be in proportional (the following, Comparative Example 1). The diffusion unit 20A is shown in which only the ejection nozzle 34 is provided without providing 40.

  In the simulation of the flow velocity fluctuation, the diffusion units 20 and 20A set the flow velocity of the air jetted from the jet nozzle 34 to the same flow velocity Vm, and the diffusion unit 20 set the flow velocity Vs of the air jetted from the sub nozzle 40 to the flow velocity Vm. It is set to 1/2 (Vs = Vm / 2), and is set so as to eject the air in parallel with the ejection direction of the air from the ejection nozzle 34. Further, the flow velocity fluctuation uses a root mean square (RMS) of the obtained velocity difference by obtaining the velocity difference of the flow velocity at each sampling time from the preset flow velocity at each sampling time.

  In the proportional diffusion portion 20A shown in FIG. 3B, an area in which the flow velocity fluctuation is extremely larger than that in the surrounding area is generated inside the air flow ejected from the ejection nozzle 34. By producing such a region where the flow velocity fluctuation is extremely large, the nonwoven fabric has improved tensile strength, but the uniformity of the meshes formed by the filaments becomes low.

  On the other hand, in the diffusion unit 20 of the first embodiment shown in FIG. 3A, the magnitude of the flow velocity fluctuation is suppressed in a region where the flow velocity fluctuation inside the air flow ejected from the ejection nozzle 34 is large as compared with the diffusion unit 20A. There is. As a result, in the diffusion unit 20, the entanglement of filaments in the web collected by the collection unit 18 is suppressed more than in the diffusion unit 20A.

  Therefore, the manufacturing apparatus 10 in which the sub nozzle 40 of the diffusion unit 20 is provided can obtain a nonwoven fabric with improved uniformity as compared with the case where the sub nozzle 40 is not provided. In addition, in the diffusion unit 20 of the present embodiment, a decrease in the tensile strength of the nonwoven fabric is suppressed because the region where the flow velocity fluctuation is larger than the surroundings remains in the transport flow.

  In the embodiment described above, the flow velocity Vs of the sub nozzle 40 is ½ of the flow velocity Vm of the ejection nozzle 34, but the present invention is not limited to this. The flow velocity Vs of the sub-nozzle 40 may be equal to or less than the flow velocity Vm of the jet nozzle 34, and thus the flow velocity fluctuation in the carrier flow can be suppressed without suppressing the spread of the carrier flow in the diffusion space 36. it can.

  The flow velocity Vs of the sub nozzle 40 may be higher than the flow velocity Vm of the ejection nozzle 34 (Vs> Vm). In this case, when the air jet direction from the sub nozzle 40 is set to be substantially parallel to the air jet direction from the jet nozzle 34, the air jetted from the sub nozzle 40 spreads the carrier flow in the diffusion space 36. May be regulated. From here, when the flow velocity Vs of the sub nozzle 40 is set to be higher than the flow velocity Vm of the ejection nozzle 34 (Vs> Vm), the sub nozzle 40 has the direction of the opening 40A or the ejection direction of the air that is ejected from the ejection nozzle 34. It is only necessary to set the direction along the carrier flow, that is, the direction in which the carrier flows in contact with the carrier flow around the carrier flow.

  Further, in the present embodiment, the sub nozzle 40 is provided in the MD direction side and the side opposite to the MD direction with respect to the ejection nozzle 34, but the sub nozzle 40 does not eject the sub nozzle 40 in the MD direction with respect to the ejection nozzle 34. It may be provided on the direction side or on the side opposite to the MD direction. That is, the sub-nozzle 40 may be one in which the sub-nozzle 40 is provided on at least one of the MD direction side and the direction opposite to the MD direction with respect to the ejection nozzle 34.

  Further, in the present embodiment, the sub nozzle 40 is provided as the air flow generation means, but the air flow generation means is not limited to the sub nozzle 40, and causes a flow of the air flow along the transport flow in the vicinity of the transport flow. Anything is fine.

Hereinafter, the present invention will be described in more detail with reference to examples. The invention is not limited to these examples.
Physical properties in the present embodiment (hereinafter, referred to as Example 1) and in contrast to the present embodiment (hereinafter, referred to as Comparative Example 1) were measured by the following methods.

(1. Unit weight [g / m ² ])
Five 100 mm (MD) x 100 mm (CD) test pieces were collected from the nonwoven fabric. In addition, the collection place (collection position) of the test piece is set to arbitrary 5 places.
Next, the mass of each test piece was measured using a plate electronic balance (manufactured by Kensei Kogyo Co., Ltd.) for each of the collected test pieces, and the average value of the mass of each test piece was obtained. The obtained average value was converted to mass per 1 m ² [g], and the second decimal place (second decimal place) was rounded off to obtain a basis weight [g / m ² ] of each test piece sample.

(2. Variation in areal weight [%])
100 pieces of 50 mm (MD) x 50 mm (CD) test pieces were sampled from the nonwoven fabric. The sampling locations were 10 in the width direction (CD) of the nonwoven fabric and 10 times in the flow direction (MD).
Then, the mass [g] of each of the collected test pieces was measured using a precision electronic balance (manufactured by Kensei Kogyo Co., Ltd.), and the average value and standard deviation of the mass of each test piece were obtained. The value obtained by dividing the standard deviation by the average value was taken as the unit weight variation [%] of each nonwoven fabric sample.

(3. Fiber diameter [μm])
Five 10 mm (MD) x 10 mm (CD) test pieces were collected from the nonwoven fabric. In addition, the collection place was one arbitrary place.
Next, the test piece was photographed at a magnification of 200 times using an optical microscope, and the photographed image was analyzed by image size measurement software (Pixs2000 Version 2.0 manufactured by Innotek Co., Ltd.). The fiber diameter of 10 fibers was measured for each test piece, the average value of the fiber diameter of each test piece was determined, and the second decimal place was rounded off to obtain the fiber diameter [μm] of each nonwoven fabric sample.

(4. Non-woven yarn bundle [dot])
One 250 mm (MD) x 200 mm (CD) test piece was sampled from the nonwoven fabric. In addition, the collection place was one arbitrary place.
Next, the non-woven fabric was visually checked, and the number of places (yarn bundles) where two or more fibers were entangled in a bundle was counted and evaluated according to the following criteria.
A: 0 yarn bundles B: 1 or more yarn bundles and less than 20 C: 20 yarn bundles or more

(5. MD 5% strength and MD strength [N / 25 mm])
Five 25 mm (CD) × 200 (MD) MD test pieces were collected from the nonwoven fabric. In addition, the collection place was arbitrary 5 places.
Then, each of the collected test pieces was stretched by using a universal tensile tester (IM-201, manufactured by Intesco) at a chuck distance of 100 mm and a tensile speed of 100 mm / min, and the chuck distance was 105 mm. The load [N] and the maximum load [N] at that time were measured. The average value of each test piece was obtained, and the second decimal place was rounded off to obtain the MD5% strength [N / 25 mm] and MD strength [N / 25 mm] of each nonwoven fabric sample. The MD5% strength corresponds to the strength when stretched by 5% in the machine direction, and the MD strength corresponds to the maximum strength when stretched in the machine direction.

(6. CD5% strength and CD strength [N / 25 mm])
Five 25 mm (MD) x 200 mm (CD) CD test pieces were collected from the nonwoven fabric. In addition, the collection place was arbitrary 5 places.
Then, each of the collected test pieces was stretched by using a universal tensile tester (IM-201, manufactured by Intesco) at a chuck distance of 100 mm and a tensile speed of 100 mm / min, and the chuck distance was 105 mm. The load [N] and the maximum load [N] at that time were measured. The average value of each test piece was determined, and the second decimal place was rounded off to obtain the CD5% strength [N / 25 mm] and CD strength [N / 25 mm] of each nonwoven fabric sample. The CD5% strength corresponds to the strength at 5% elongation in the direction perpendicular to the machine direction, and the CD strength corresponds to the maximum strength when elongated in the direction perpendicular to the machine direction.

(Example 1)
As the first propylene polymer, a propylene homopolymer having a melting point of 162 ° C. and an MFR (measured at a temperature of 230 ° C. and a load of 2.16 kg according to ASTM D1238, the same applies hereinafter) 60 g / 10 min was used. As the second propylene-based polymer, a propylene / ethylene random copolymer having a melting point of 142 ° C., an MFR of 60 g / 10 minutes and an ethylene unit component content of 4.0 mol% was used. Using the first propylene polymer and the second propylene-based polymer, composite melt spinning was performed by a spunbond method, the core was a propylene homopolymer, and the sheath was a propylene / ethylene random copolymer ( Eccentric core-sheath type composite continuous fibers having a core / sheath = 20/80 (weight ratio) were obtained as fibers.

  The obtained fiber was dispersed from the main nozzle (jet nozzle 34) shown in FIG. 1 and was volumed on the collection medium (moving zone 32). At this time, the velocity of the air jetted from the jet nozzle 34 (main nozzle) is 107.3 m / sec, and the sub nozzle provided at a position 38 mm apart in the horizontal direction from the jet outlet (opening 34A) of the jet nozzle 34. The air ejected from the nozzle 40 (ejection width 12 mm) was set to 1/4 (26.8 m / sec) with respect to the velocity of the air ejected from the ejection nozzle 34.

Then, it is peeled from the collection medium, and the embossed pattern has an area ratio of 6.7%, an embossed area of 0.19 m ² , and is heat-bonded by heating embossing under the conditions of a heating temperature of 130 ° C. and a linear pressure of 60 kg / cm. A spunbond nonwoven fabric was obtained. The unit weight of the obtained spunbonded nonwoven fabric was 20.0 g / m ² . The obtained spunbonded nonwoven fabric was evaluated by the method described above. The evaluation result is shown in FIG.

(Comparative Example 1)
A spunbonded nonwoven fabric was obtained in the same manner as in Example 1 except that the air ejected from the sub nozzle 40 was set to 0 (velocity 0 m / sec). The basis weight of the obtained spunbonded nonwoven fabric was 20.2 g / m ² . The obtained spunbonded nonwoven fabric was evaluated by the method described above. The evaluation result is shown in FIG.

  Here, the variation in the areal weight was 3.5% in Comparative Example 1 and 2.0% in Example 1. Further, the evaluation of the yarn bundle [point] in the nonwoven fabric was evaluated B in Example 1 and evaluated C in Comparative Example 1. At this time, the MD5% strength was 4.3 [N / 25 mm] in Example 1 and 5.2 [N / 25 mm] in Comparative Example 1, and the CD5% strength was 2.7 [N] in Example 1. / 25 mm] and Comparative Example 1 was 1.2 [N / 25 mm]. In addition, the MD5% strength / CD5% strength was 1.6 in Example 1 and 4.3 in Comparative Example 1. From this, it can be seen that in comparison with Comparative Example 1, Example 1 has suppressed strength reduction and improved uniformity.

  Therefore, the non-woven fabric manufacturing apparatus and method according to the present embodiment are suitable for producing non-woven fabric in which strength reduction is suppressed and uniformity is improved. In addition, the nonwoven fabric manufacturing apparatus and method according to the present embodiment are 5% stretchable in the machine direction (MD direction) with respect to the strength (CD5% strength) at 5% stretch in the direction perpendicular to the machine direction (CD direction). It is suitable for the production of a nonwoven fabric having a strength (MD5% strength) ratio (MD5% strength / CD5% strength) of 2.0 or less.

Furthermore, the nonwoven fabric manufacturing apparatus and method according to the present embodiment are suitable for manufacturing a nonwoven fabric having a unit weight variation of preferably 3.0% or less, more preferably 2.5% or less.
Further, in the nonwoven fabric manufacturing apparatus and manufacturing method according to the present embodiment, the maximum strength (MD strength) when stretched in the machine direction is 37.5 [N / 25 mm] or more, more preferably 40.0 [N. / 25 mm], most preferably 42.5 [N / 25 mm].

The disclosure of Japanese Patent Application No. 2016-020144 is incorporated herein by reference in its entirety.
All publications, patent applications, and technical standards mentioned herein are to the same extent as if each individual publication, patent application, and technical standard were specifically and individually noted to be incorporated by reference, Incorporated herein by reference.

10 Manufacturing Equipment 12 Spinning Section 14 Cooling Section 16 Stretching Section 18 Collection Section 20 Diffusion Section 32 Moving Zone 32A Collection Surface 34 Jet Nozzle 36 Diffusion Space 38 Transport Stream 40 Sub-Nozzle 44 Airflow Layer

Claims (2)

  A spunbond nonwoven fabric, wherein the ratio of the strength at 5% elongation in the machine direction to the strength at 5% elongation in the direction perpendicular to the machine direction is 2.0 or less and the areal variation is 3.0% or less. Bonded non-woven fabric. The spunbonded nonwoven fabric according to claim 1, which has a maximum strength of 35.0 (N / 25 mm) or more when stretched in the machine direction.