JP6351298B2 - Dehydrator for a sheet containing a plurality of types of fibers, a method for dehydrating the sheet, and a method for producing a nonwoven fabric for wet tissue - Google Patents

Description

  The present disclosure provides a dehydrator for a sheet including a first fiber having a first average fiber length and a second fiber having a second average fiber length longer than the first average fiber length, the sheet The present invention relates to a method for dewatering and a method for producing a nonwoven fabric for wet tissue.

  As a nonwoven fabric used for a wet tissue or the like, a nonwoven fabric manufactured by injecting a high-pressure water stream onto a web sheet containing fibers to entangle the fibers is known.

  For example, in Patent Document 1, a water flow is jetted onto a fiber web while the fiber web is placed on a belt that is a support and water that interferes with the fiber entanglement is sucked from below the belt by suction means. Yes.

  Further, in Patent Document 2, the fiber material layer 1 is placed on the second support 4 and sprayed onto the fiber material layer 1 with the nozzle 5 while sucking water with the suction 7, so that the fibers of the fiber material layer 1 Is described. A mesh screen is mentioned as a 2nd support body, In the Example, the plain weave 15-18 mesh screen of the polyester monofilament is used.

  Furthermore, Patent Document 3 describes that a pattern net such as a plain weave, a cedar weave, a twill weave, or a spiral weave can be used as a support when forming a predetermined pattern on a fiber web with a high-pressure water stream. .

JP-A 62-69867 JP-A-63-182460 JP 2013-64226 A

However, Patent Documents 1 to 3 do not consider that fiber dirt adheres to the support and that the sheet is dehydrated while washing the fiber dirt attached to the support.
Therefore, an object of the present disclosure is to provide a dehydrator that dehydrates a sheet while cleaning dirt adhering to a mesh belt.

  As a result of intensive studies to solve the above-described problems, the present disclosure has revealed that a first fiber having a first average fiber length and a second fiber having a second average fiber length longer than the first average fiber length. A dehydrator for a sheet including two fibers, wherein the dehydrator is (i) a mesh belt for transporting the sheet placed thereon, the surface on the sheet side and the opposite side thereof And (ii) a mesh belt that passes through a conveyance area that conveys the sheet and a cleaning area that cleans the mesh belt, and (ii) is disposed below the mesh belt in the conveyance area, A suction unit having a suction port for sucking moisture contained in the sheet through the mesh belt, and (iii) the mesh disposed in the transport area and / or the washing area The mesh belt is formed of a plurality of vertical wires extending in the sheet conveyance direction and a plurality of horizontal wires extending in a direction orthogonal to the sheet conveyance direction. A dehydrator characterized in that the horizontal wire on the surface side returns to the surface side after traversing one vertical wire on the back surface side in the woven structure is found. .

  The dehydrator of the present disclosure dehydrates a sheet while cleaning dirt adhering to the mesh belt.

FIG. 1 is a perspective view of a dehydrator 1 according to one of the embodiments of the present disclosure. FIG. 2 is an enlarged view of a portion II of the mesh belt 2 shown in FIG. 3 is an end view taken along the line III-III in FIG. FIG. 4 is an end view taken along the IV-IV end face of FIG. FIG. 5 shows the complete organization 24 shown in FIG. 2 in an organization chart. FIG. 6 is a diagram for explaining the dirt on the mesh belt 2 when the sheet 2 including a plurality of types of fibers is dehydrated. FIG. 7 is a view for explaining dirt on the mesh belt 2 when the sheet 2 including a plurality of types of fibers is dehydrated. FIG. 8 is a cross-sectional view in the orthogonal direction CD in the XIII-XIII cross section of FIG. FIG. 9 is a cross-sectional view in the orthogonal direction CD in the IX-IX cross section of FIG. FIG. 10 is a cross-sectional view in the orthogonal direction CD in the XX cross section of FIG. FIG. 11A is a diagram for explaining the cleaning of the mesh belt. FIG. 11B is a diagram for explaining the cleaning of the mesh belt. FIG. 12 is a diagram showing an organization chart of a mesh belt having a woven structure with a four-tear pattern that has a vertical-slanted pattern. FIG. 13 is a diagram for explaining how the mesh belt 2 shown in FIG. 12 is cleaned by the back surface cleaning brush 8 ′. FIG. 14 is a perspective view showing a dehydrator according to another embodiment of the present disclosure. FIG. 15 is a diagram for describing the dehydration method of the present disclosure. FIG. 16 is a diagram illustrating an example of a wet tissue nonwoven fabric manufacturing apparatus used in the wet tissue nonwoven fabric manufacturing method of the present disclosure. FIG. 17 is a diagram for explaining the mesh belt used in Example 3. FIG. 18 is a diagram for explaining the mesh belt used in Example 4.

[Definition]
First, some of the terms used in this specification are defined.
[Weaving organization]
In this specification, the “woven structure” related to the mesh belt means a structure formed by weaving a vertical wire and a horizontal wire.
[Complete organization]
As used herein, “complete structure” means the smallest unit of woven structure.

[Overlapping points]
In the present specification, the “overlapping point” means a point where the vertical wire and the horizontal wire overlap in the thickness direction of the mesh belt.

[Organization point]
In the present specification, the “texture point” is again after the wire on a certain surface among the overlapping points described above moves to the opposite surface and crosses one orthogonal wire on the opposite surface. It means the point of crossing back to the surface.
In the present specification, among the above-described overlapping points, points other than the tissue points are referred to as “non-organization points”.
[Tissue point density]
In this specification, “tissue point density” means the ratio of the number of tissue points to the number of overlapping points, and is calculated by the following equation.
Tissue point density = tissue point / overlapping point

[Continuous organization points]
In the present specification, the texture points are continuous in an oblique direction means that at least two texture points are in a positional relationship in which one overlap point is shifted in the vertical wire direction and one overlap point in the horizontal wire direction. Means that.
In this specification, “continuous in the oblique direction” of the tissue points may be simply referred to as “continuous of the tissue points”.
Moreover, each structure point is not adjacent to the vertical wire direction or the horizontal wire direction by definition.

[Floating wire]
In the present disclosure, in accordance with the customs of the textile industry, the fact that there are more horizontal wires than vertical wires on a certain surface may be expressed as the horizontal wire floating on a certain surface. For example, as will be described later, in the woven structure 23 shown in FIG. 2, the horizontal wire is floating on the front surface 3 of the mesh belt 2, and the vertical wire is floating on the back surface 4.

[Average fiber length]
In the present disclosure, the average fiber length of the fiber including the first fiber, the second fiber, and the optional third fiber means a length-weighted average fiber length, and is a Kajaani fiber manufactured by Metso Automation. L (l) value measured by Lab Fiber Properties (offline) [kajaani Fiber Lab properties (off-line)].

<Dehydrator>
The dehydrator of the present disclosure will be described in detail below.
FIG. 1 is a perspective view of a dehydrator 1 according to one of the embodiments of the present disclosure. The dehydrator 1 shown in FIG. 1 is for a sheet including a first fiber having a first average fiber length and a second fiber having a second average fiber length longer than the first average fiber length. And has a mesh belt 2, a plurality of suction units 7, and a back surface cleaning unit 8 as a cleaning unit.

  The mesh belt 2 has a front surface 3 on which a sheet (not shown) is carried and conveyed, and a back surface 4 on the opposite side, and a plurality of vertical wires (not shown) extending in the sheet conveying direction MD. ) And a plurality of horizontal wires (not shown) extending in the orthogonal direction CD orthogonal to the sheet conveying direction MD.

  In addition, the sheet | seat containing the 1st fiber which has 1st average fiber length, and the 2nd fiber which has 2nd average fiber length longer than 1st average fiber length is used. Sometimes referred to as “sheet”, “sheet”, or the like.

The mesh belt 2 alternately passes through a conveyance area 5 for conveying a sheet and a cleaning area 6 for cleaning the mesh belt 2.
The plurality of suction units 7 are arranged at the lower part of the mesh belt 2 in the transport area 5 and have suction ports 7′A, 7 ″ A for sucking moisture contained in the sheet (not shown) through the mesh belt 2. Prepare.

  In the dehydrator 1 shown in FIG. 1, the back surface cleaning unit 8 is disposed in the transport area 5 and removes the first fibers (not shown) attached to the mesh belt 2 from the back surface 4 side of the mesh belt 2. . More specifically, in the dehydrator 1 shown in FIG. 1, the back surface cleaning unit 8 is composed of a back surface cleaning brush, the back surface cleaning brush is a fixed brush, and from the back surface 4 side of the mesh belt 2, First fibers (not shown) attached to the mesh belt 2 are scraped off.

  In the dehydrator 1 shown in FIG. 1, the back surface cleaning unit 8 includes a first first suction unit 7 ′ and a second second suction unit 7 ″ counted from the upstream side of the transfer area 5. It is arranged between.

  The dehydrator 1 shown in FIG. 1 includes a surface cleaning unit 9 in the cleaning area 6 for removing the first fibers attached to the mesh belt 2 from the surface 3 side of the mesh belt 2. The surface cleaning unit 9 includes a surface cleaning brush, and the surface cleaning brush is a fixed brush.

In the dehydrator 1 shown in FIG. 1, the mesh belt 2 is also an endless mesh belt, and the mesh belt 2 passes through the conveyance area 5 and the cleaning area 6 alternately.
In the dehydrator 1 shown in FIG. 1, the mesh belt 2 includes five back rolls 10 ′, 10 ″, 10 ′ ″, 10 ″ ″ and 10 ′ ″ that are in contact with the back surface 4 of the mesh belt 2. '' And surface rolls 11 ′ and 11 ″ in contact with the surface 3 of the mesh belt 2 disposed in the cleaning area 6.

The dehydrator 1 shown in FIG. 1 includes a surface roll cleaning unit 12 ′ and a surface roll cleaning unit 12 ″ for removing the first fibers attached to the surface roll 11 ′ and the surface roll 11 ″, respectively. Have. The surface roll cleaning unit 12 ′ includes a surface roll water spraying portion 14 ′ for spraying water on the surface roll 11 ′ and a roll cleaning brush 13 ′ for cleaning the surface roll 11 ′. The roll cleaning brush 13 ′ is a fixed brush, and the tip of the brush is in contact with the surface roll 11 ′.

  The surface roll cleaning unit 12 ′ further includes a mesh belt water spray unit 15 that sprays water on the back surface 4 of the mesh belt 2 disposed on the upstream side of the transport direction MD of the surface roll cleaning unit 12 ′.

The surface roll cleaning unit 12 '' includes a surface roll water spraying portion 14 '' for spraying water on the surface roll 11 '' and a roll cleaning brush 13 '' for cleaning the surface roll 11 ''. The roll cleaning brush 13 ″ is a rotatable brush having a rotation axis in a direction crossing the conveyance direction MD, and the tip of the brush is in contact with the surface roll 11 ″.

  FIG. 2 is an enlarged view of a portion II of the mesh belt 2 shown in FIG. In FIG. 2, the upper part is the transport direction MD, the left-right direction is the orthogonal direction CD orthogonal to the transport direction, and the front side is the surface 3. The mesh belt 2 shown in FIG. 2 has a woven structure 23 formed of a plurality of vertical wires 21 extending in the sheet conveying direction MD and a plurality of horizontal wires 22 extending in the sheet orthogonal direction CD.

In FIG. 2, the numbers of vertical and horizontal wires (hereinafter sometimes simply referred to as “wires”) are selected for the purpose of explanation, and do not indicate the number of wires in the portion II in FIG. 1.
In the woven structure 23 shown in FIG. 2, the horizontal wire is floating on the front surface 3 of the mesh belt 2, and the vertical wire is floating on the back surface 4 side of the mesh belt 2.

  FIG. 3 is an end view of the III-III end surface of FIG. 2, and the horizontal direction is the orthogonal direction CD. In the woven structure 23 shown in FIG. 3, the horizontal wire 22 on the back surface 4 side crosses three vertical wires on the front surface 3 side and then returns to the back surface side 4 to form an arch portion 25 that protrudes on the front surface side. To do. Further, the horizontal wire 22 on the front surface 3 side returns to the front surface 3 side after traversing one vertical wire 21 on the back surface 4 side, and forms an arch portion 26 protruding in the back surface side.

FIG. 4 is an end view of the IV-IV end face of FIG. 2, and the left direction is the transport direction MD. In the woven structure 23 shown in FIG. 4, the vertical wire 21 on the back surface 4 side crosses one horizontal wire 22 on the front surface 3 side, returns to the back surface 4 side, and has an arch portion 25 projecting on the front surface side. Forming. Further, in the woven structure 23 shown in FIG. 4, the vertical wire 21 on the front surface 3 side returns to the front surface 3 side after traversing the three horizontal wires 22 on the back surface 4 side, and protrudes on the back side. Is forming.
In FIG. 2 to FIG. 4, for the sake of convenience, the vertical wire is indicated by a dark color and the horizontal wire is indicated by a white color to distinguish the two wires.

The mesh belt 2 shown in FIG. 2 has a complete structure 24 formed of four vertical wires 21 and four horizontal wires 22.
FIG. 5 shows the complete organization 24 shown in FIG. 2 in an organization chart. In FIG. 5, as in FIG. 2, the direction from the bottom to the top is the transport direction (MD), the left-right direction is the orthogonal direction (CD), and the front side is the surface 3. Further, in FIG. 5, as in FIGS. 2 to 4, the vertical wire 21 is shown in dark color, and the horizontal wire 22 is shown in white to distinguish both wires.

  The woven structure shown in FIG. 5 is generally called a four-sheet teared oblique text, and is a four-faced oblique text with a horizontal wire floating on the surface 3.

Next, cleaning of the woven structure shown in FIG. 5 will be described with reference to FIGS.
FIG. 6 and FIG. 7 are diagrams for explaining soiling of the mesh belt 2 when the sheet 2 including a plurality of types of fibers is dehydrated. 6 is a cross-sectional view taken along the line VI-VI in FIG. 2, and FIG. 7 is a cross-sectional view taken along the line VII-VII in FIG.
6 and 7, a sheet 31 including a plurality of types of fibers to be conveyed exists on the mesh belt 2.

6 and 7, when the sheet 31 including a plurality of types of fibers is dehydrated from the suction unit 7, the sheet 31 including the plurality of types of fibers has an average fiber length shorter than the average fiber length of the second fibers. A part of the first fiber moves to the suction unit 7 together with the sucked water, and a part of the first fiber adheres to the mesh belt 2. More specifically, the first fiber hangs down from the vertical wire 21 and / or the horizontal wire 22 in a state in which both ends thereof are directed in the direction opposite to the sheet 31 including a plurality of types of fibers (the suction unit direction). First fibers 32 on the vertical wire and first fibers 33 on the horizontal wire are formed.
In practice, there may be a first fiber that hangs down from both the vertical wire and the horizontal wire, but is omitted for the sake of explanation.

In general, the mesh belt is tensioned in the conveyance direction MD and is not tensioned in the orthogonal direction CD. Therefore, the vertical wire extending in the conveyance direction MD has a thickness of the mesh belt. The horizontal wire extending in the orthogonal direction CD has a small displacement in the thickness direction of the mesh belt (see D ₁ in FIG. 3) with little displacement in the direction (see D ₂ in FIG. 4).

A mechanism of easy cleaning of the mesh belt of the dehydrator of the present disclosure will be described.
FIG. 8 is a cross-sectional view in the orthogonal direction CD in the XIII-XIII cross section of FIG. In FIG. 8, the back surface cleaning brush 8 ′ as the back surface cleaning unit is a fixed brush, and the tip of the back surface cleaning brush 8 ′ is in contact with the back surface 4, and is applied to the mesh belt 2 from the back surface 4 side of the mesh belt 2. The attached first fibers (not shown) are scraped off. As FIG.6 and FIG.7 shows, since the both ends are facing the back surface cleaning brush 8 'side, the 1st fiber is easy to be scraped off by the back surface cleaning brush 8'.
In addition, in FIG. 8, the 1st fiber on a vertical wire and the 1st fiber on a horizontal wire are abbreviate | omitted for description.

  Moreover, in FIG. 8, since the arch part 25 which protrudes on the surface side of the horizontal wire 22 is formed so as to straddle the three vertical wires 21, the recessed portion 25 ′ is large, and the back surface cleaning brush 8 ′. Easy to clean with the tip of

  FIG. 9 is a cross-sectional view in the orthogonal direction CD in the IX-IX cross section of FIG. 1, and schematically shows the mesh belt 2 after being cleaned by the back surface cleaning brush 8 ′. In the mesh belt 2 shown in FIG. 9, the first fibers on the vertical wires are removed, and the first fibers 33 on the horizontal wires are attached to the mesh belt 2.

FIG. 10 is a cross-sectional view in the orthogonal direction CD in the XX cross section of FIG. When water (not shown) is sprayed to the mesh belt 2 from the nozzle 15 ′ of the mesh belt water spray unit 15 of the surface roll cleaning unit 12 ′, the first fibers on the horizontal wire that adhere to the horizontal wire 22 33, both ends move to the surface 3 side of the mesh belt 2, and then the first fibers 33 on the horizontal wire move from the horizontal wire 22 to the surface roll 11 ′ and wind around the surface roll 11 ′. . As a result, the mesh belt 2 is cleaned.
In FIG. 10, the nozzle 15 ′ and the mesh belt 2 do not reflect actual sizes.

  The 1st fiber which moved to surface roll 11 'floats from the surface of surface roll 11' with the water sprayed by water spray part 14 'for surface rolls, and then from surface roll 11' by roll washing brush 13 '. Removed.

  In the dehydrator 1 shown in FIG. 1, the mechanism by which the surface roll cleaning unit 12 ″ cleans the mesh belt is the same as that of the surface roll cleaning unit 12 ′. That is, the first fiber moves to the surface roll 11 ″ by contacting the surface roll 11 ″, and then the first fiber is caused by the water sprayed by the surface roll water spraying portion 14 ″. Floating from the surface of the surface roll 11 ″, the first fibers are then removed from the surface roll 11 ′ by the roll cleaning brush 13 ″.

  Further, the dehydrator 1 shown in FIG. 1 includes a surface cleaning unit 9 and removes dirt remaining on the mesh belt 2, for example, first fibers, in particular, first fibers on a horizontal wire, Preparation for conveying a sheet containing a plurality of types of fibers.

  In the dehydrator of the present disclosure, as the cleaning unit, for example, (a) a back surface cleaning unit for removing the first fibers attached to the mesh belt from the back surface side of the mesh belt, which is disposed in the conveyance area, (b ) A surface cleaning unit for removing the first fibers attached to the mesh belt from the surface side of the mesh belt disposed in the cleaning area, and (c) for removing the first fibers attached to the surface roll. And a surface roll cleaning unit.

In the embodiment shown in FIG. 1, the back surface cleaning unit 8 comprises a back surface cleaning brush, and the back surface cleaning brush is a fixed brush, but in a dehydrator according to another embodiment of the present disclosure, the back surface cleaning brush The unit includes a back surface cleaning brush, and the back surface cleaning brush is a rotatable brush having a rotation axis in a direction intersecting the transport direction.
The direction intersecting the transport direction is arbitrary, but considering the cleaning properties, the direction perpendicular to the transport direction is preferable.
By adopting a rotatable brush, the degree of cleaning can be changed according to the degree of dirt attached to the mesh belt. For example, when the dirt attached to the mesh belt is severe, the rotatable brush can be rotated with the mesh belt by rotating it in a reverse direction so that the portion in contact with the mesh belt moves in the direction opposite to the mesh belt conveyance direction. By increasing the relative speed with the brush, dirt attached to the mesh belt can be removed.

  If there is not much dirt adhering to the mesh belt, the rotatable brush is rotated forward so that the portion in contact with the mesh belt moves in the same direction as the mesh belt conveyance direction, or the rotatable brush. By freely rotating the belt, the relative speed with the mesh belt can be reduced, and the wear of the mesh belt can be suppressed.

  In the dehydrator of the present disclosure, in the embodiment in which the back surface cleaning unit includes a rotatable brush, the rotation speed of the rotatable brush is not particularly limited, but the peripheral speed at the position in contact with the mesh belt is relative to the conveyance direction. Preferably -30 to +30 m / min, and more preferably -20 to +20 m / min.

  In the dehydrator according to another embodiment of the present disclosure, the back surface cleaning unit further includes a water spray unit that sprays water onto the back surface cleaning brush or the mesh belt.

  In the dehydrator of the present disclosure, the material of the back surface cleaning brush included in the back surface cleaning unit is preferably one having the same hardness as the material of the mesh belt from the viewpoint of protecting the mesh belt, for example, a synthetic resin, for example, And polypropylene. The material of the mesh belt will be described later. Further, the length of the brush part of the back surface cleaning brush is not particularly limited as long as it can remove dirt adhered to the mesh belt, but the brush part is, for example, 20 to 100 mm, preferably 30 to 80 mm, and more Preferably it has a length of 40-60 mm.

  In the dehydrator 1 shown in FIG. 1, the back surface cleaning unit 8 includes a first first suction unit 7 ′ and a second second suction unit 7 ″ counted from the upstream side of the transfer area 5. However, in the dehydrator of the present disclosure, the position of the back surface cleaning unit is not particularly limited as long as it is within the transfer area. In another embodiment of the present disclosure, the backside cleaning unit is disposed before all suction units, between a plurality of suction units, or after all suction units.

  Although the position of the back surface cleaning unit is arbitrary, for example, when the first fiber is difficult to drop off from the sheet, the back surface cleaning unit can be arranged after all the suction units, and the first fiber from the sheet Can easily fall off and the mesh belt is easily clogged, the back surface cleaning unit can be arranged immediately after the first suction unit counting from the upstream side of the transport area.

In the embodiment in which the dehydrator of the present disclosure includes the surface roll cleaning unit, the roll cleaning brush of the surface roll cleaning unit is the same as the back surface cleaning brush, that is, a fixed brush or a direction that intersects the transport direction. A rotatable brush having a rotation axis can be mentioned. The fixed brush and the rotatable brush are as described in the section of the back surface cleaning brush.
By adopting a rotatable brush, the direction of rotation can be changed according to the degree of dirt attached to the surface belt.

In the embodiment in which the dehydrator of the present disclosure includes the surface roll cleaning unit, the surface roll water spraying unit of the surface roll cleaning unit is not particularly limited as long as it can spray water on the surface roll, but the surface roll water spraying is not limited. The surface of the water stream having a water pressure of preferably 3.0 to 9.0 MPa, more preferably 3.0 to 7.0 MPa, and even more preferably 3.0 to 5.0 MPa at the outlet of the water spraying part. Spray on the roll.
By spraying the water flow in the above range, not only the first fibers attached to the surface roll can be floated but also a part of the first fibers are removed from the surface roll.

The water spray part for the surface roll preferably blows a water flow onto the surface roll at a flow rate of 5 to 50 L / min / m, more preferably 10 to 45 L / min / m, and even more preferably 15 to 40 L / min / m. wear. This is from the viewpoint of the detergency of the first fiber.
1 L / min / m means that 1 L of water flow is sprayed per minute per 1 m in the orthogonal direction of the surface roll.

  The water spray portion for the surface roll preferably sprays a water stream on the surface roll at intervals of 50 cm or less, more preferably 35 cm or less, and even more preferably 20 cm or less. The surface roll water spraying section preferably has a plurality of nozzles, and the nozzles preferably have a diameter of 5 mm or less, more preferably 4 mm or less, and even more preferably 3 mm or less.

  In an embodiment in which the dehydrator of the present disclosure includes a surface roll cleaning unit and the surface roll cleaning unit further includes a mesh belt water spraying unit, the mesh belt water spraying unit is at the outlet of the water spraying unit from the back surface of the mesh belt. A water stream having a water pressure of 3.0 to 9.0 MPa, more preferably 3.0 to 7.0 MPa, and even more preferably 3.0 to 5.0 MPa is sprayed on the mesh belt.

When the water pressure is less than 3.0 MPa, both ends of the first fiber attached to the mesh belt do not move to the surface side of the mesh belt, and the first fiber becomes difficult to move to the surface belt. Further, when the water pressure exceeds 9.0 MPa, problems such as disturbance of the woven structure of the mesh belt, breakage of the mesh belt, and easy wear may occur due to the high water pressure.
It is preferable that the water spraying part for mesh belts sprays water in the thickness direction of a mesh belt from a viewpoint of efficiency.

  The mesh belt water spraying section preferably blows a water flow to the mesh belt at a flow rate of 5 to 50 L / min / m, more preferably 10 to 45 L / min / m, and even more preferably 15 to 40 L / min / m. wear. This is from the viewpoint of moving the first fibers to the surface belt.

  The mesh belt water spraying section sprays water on the mesh belt at an interval of preferably 50 cm or less, more preferably 35 cm or less, and even more preferably 20 cm or less. This is from the viewpoint of moving the first fibers to the surface belt. The mesh belt water spraying section preferably has a plurality of nozzles, and the nozzles preferably have a diameter of 5 mm or less, more preferably 4 mm or less, and even more preferably 3 mm or less.

In the embodiment shown in FIG. 1, the surface cleaning unit 9 comprises a surface cleaning brush and the surface cleaning brush is a fixed brush, but in a dehydrator according to another embodiment of the present disclosure, the surface cleaning unit Includes a surface cleaning brush, and the surface cleaning brush is a rotatable brush having a rotation axis in a direction intersecting the conveying direction. The fixed brush and the rotatable brush are as described in the section of the back surface cleaning brush.
By adopting a rotatable brush, the degree of cleaning can be changed according to the degree of dirt adhering to the mesh belt, similarly to the back surface cleaning brush.

Next, the mesh belt will be described.
The mesh belt provided in the dehydrator of the present disclosure has a woven structure formed from a plurality of vertical wires extending in the sheet conveyance direction and a plurality of horizontal wires extending in an orthogonal direction orthogonal to the sheet conveyance direction. If there is, there is no particular limitation.

  In the woven structure, the horizontal wire on the front surface side moves to the back surface side, and preferably returns to the front surface side after traversing one vertical wire material on the back surface side, preferably 2 or less. The horizontal wire existing on the back surface side prevents the back surface cleaning unit from coming into contact with the vertical wire material like the arch portion 26 protruding in the back surface side shown in FIG. Therefore, in consideration of the frequency with which the back surface cleaning unit cleans the vertical wire, it is preferable that the horizontal wire is present more on the front side than the back side (that is, the horizontal wire is floating on the front side).

  Further, in the above woven structure, the horizontal wire on the back surface side moves to the front surface side, and preferably returns on the back surface side after traversing two or more, more preferably three or more vertical wires on the front surface side. This is because the horizontal wire is present more on the front side than on the back side (that is, the horizontal wire is floating on the front side).

In addition, the horizontal wire on the back side moves to the front side, and on the front side, preferably 2 or more, more preferably 3 or more vertical wires after crossing back to the back side, This is also preferable from the viewpoint of difficulty in clogging at overlapping points.
11A and 11B are perspective views when the back surface cleaning brush 8 ″ cleans the mesh belt 2, respectively. 11A and 11B both show only three vertical wires 21 and one horizontal wire 22 for explanation.

  The mesh belt 2 shown in FIG. 11A has a woven structure in which the horizontal wire 22 on the back surface side moves to the front surface 3 side and crosses one vertical wire 21 on the front surface 3 side and then returns to the back surface 4 side. . In the woven structure, when the back surface cleaning brush 8 ′ moves to the position of the back surface cleaning brush 8 ″, the first fibers 32 ′ on the vertical wire move from the mesh belt 2 while moving in the direction opposite to the conveying direction MD. The first fibers 32 ′ on the vertical wire that are removed but remain without being removed cannot stay beyond the tissue points 27 and stay at the tissue points 27, and the first fibers 32 on the vertical wires. '' Form. This is because, at the tissue point, the pressure for pressing the vertical wire and the horizontal wire is high, and it is difficult for the first fiber to pass through the gap.

  The first fibers 32 '' on the vertical wire staying at the tissue point 27 can be removed by a back surface cleaning brush (not shown) that comes into contact with the first fiber 32 ''. It is easy to clog the gap between. Further, at the tissue point 27, the horizontal wire 22 is unlikely to change its position in the transport direction MD, that is, the flexibility of the surface of the horizontal wire 22 is low, and clogged fragments are difficult to be removed by subsequent cleaning.

  The mesh belt 2 shown in FIG. 11B has a woven structure in which the horizontal wire 22 on the back surface side moves to the front surface 3 side, crosses the three vertical wires 21 on the front surface 3 side, and then returns to the back surface 4 side. . In the woven structure, when the back surface cleaning brush 8 ′ moves to the position of the back surface cleaning brush 8 ″, the first fibers 32 ′ on the vertical wire move from the mesh belt 2 while moving in the direction opposite to the conveying direction MD. The first fiber 32 ′ on the vertical wire that is removed but not removed moves beyond the non-texture point 28 to the position of the first fiber 32 ″ on the vertical wire. At the non-textured point, the pressure for pressing the vertical wire and the horizontal wire is lower than that at the textured point, and the first fiber easily passes through the gap.

  Further, even when the first fibers 32 ′ on the vertical wire rods temporarily stay between the vertical wire rods 21 and the horizontal wire rods 22 at the non-overlapping points 28 and the fragments remain, At the contact point 28, the position of the horizontal wire 22 is easily changed in the transport direction MD, that is, the surface of the horizontal wire 22 is highly flexible, and the clogged fiber fragments are easily removed by subsequent cleaning.

  Furthermore, in the woven structure of the mesh belt of the dehydrator of the present disclosure, it is preferable that the vertical wire is disposed corresponding to the horizontal wire. That is, the vertical wire on the back surface side moves to the front surface side, and preferably returns to the back surface side after traversing two or less, more preferably one horizontal wire on the front surface side. Further, in the woven structure of the mesh belt of the dehydrator of the present disclosure, the vertical wire on the front side moves to the back side, and preferably crosses at least two, more preferably three or more horizontal wires on the back side. After returning to the surface side.

  The woven structure of the mesh belt of the dehydrator of the present disclosure preferably has a 3 × 3 to 10 × 10 complete structure, more preferably 3 × 3 to 8 × 8 complete structure. More preferably, it has a 6 × 6 complete structure, more preferably a 3 × 3-5 × 5 complete structure, and preferably a 4 × 4 complete structure.

  Although it depends on the tissue point density, in general, when the complete structure of the mesh belt is less than 3 × 3, the tissue point density increases, and the flexibility of the horizontal wire, particularly on the surface, tends to decrease. The belt tends to be difficult to clean. When the complete structure of the mesh belt exceeds 10 × 10, the flexibility of the horizontal wire, particularly the surface, is improved, but the tissue point density is lowered and the strength of the mesh belt tends to be lowered.

The mesh belt of the dehydrator of the present disclosure preferably has a tissue point density of 1/10 to 1/3, more preferably 1/8 to 1/3, and 1/6 to 1 It is more preferable to have a tissue point density of / 3, more preferable to have a texture point density of 1/5 to 1/3, and still more preferable to have a texture point density of 1/4.
When the tissue point density is less than 1/10, the strength of the mesh belt is weakened, the opening of the vertical and horizontal wires is lowered, the air permeability of the mesh belt tends to be lowered, and the tissue point density is 1 If it exceeds / 3, the strength of the mesh belt increases, but the opening of the vertical and horizontal wires increases, and the first fibers tend to fall off the sheet.

  In the mesh belt of the dehydrator of the present disclosure, the vertical wire mesh opening, which is the interval between adjacent vertical wire materials, varies depending on the type of sheet containing fibers to be dehydrated. Is 0.050 to 0.140 mm, preferably 0.060 to 0.130 mm, and more preferably 0.070 to 0.120 mm.

  If the vertical wire opening exceeds 0.140 mm, the first fibers may fall off the sheet and become entangled with the mesh belt, or may be sucked from the suction unit. On the other hand, if the vertical wire opening is less than 0.050 mm, the air permeability of the mesh belt is lowered, and it may be difficult to suck water to be dehydrated.

The above problem is particularly noticeable when the first fiber is pulp and the fiber length is 2 to 3 mm.
Since the mesh belt is tensioned in the conveying direction during use, the above-described vertical wire mesh opening is particularly important in order to prevent the first fibers from falling off the sheet.

  In the mesh belt of the dehydrator of the present disclosure, the horizontal wire opening that is the interval between adjacent horizontal wires is likely to change during dehydration. This is because the mesh belt is often not tensioned in the orthogonal direction during use, and its position can be easily changed as compared with the vertical wire.

  Therefore, in the mesh belt of the present disclosure, the control of the air permeability and the ease of dropping of the first fibers is controlled by the opening of the vertical wire, and the horizontal wire preferably has a larger opening than the vertical wire. And generally has an aperture of 0.100 to 0.300 mm, preferably 0.120 to 260 mm, and more preferably 0.140 to 0.220 mm.

In the present disclosure, the openings of the vertical wire and the horizontal wire are measured as follows.
(1) A Keyence digital microscope VHX-1000 and a mesh belt are prepared in a temperature-controlled room at 20 ° C. and left to stand for 24 hours.
(2) Using the above-described microscope, measure the width of 10 mesh wire vertical wires in a total of 10 places, and calculate the average value W ₁ .
(3) The opening O _l of the vertical wire is _expressed by the following formula:
O _l = (W ₁ −10 × D _l ) / 9
In addition, _Dl means the diameter of a vertical wire, The measuring method is mentioned later.

(4) Using the above-mentioned microscope, the width of 10 horizontal wires of the mesh belt is measured in 10 places in total, and the average value W _c is calculated.
(5) The opening O _c of the horizontal wire is expressed by the following formula:
O _c = (W _c −10 × D _c ) / 9
Incidentally, D _c denotes the diameter of the horizontal member, for the measurement method will be described later.

In the mesh belt of the dehydrator of the present disclosure, the diameter of the vertical wire varies depending on the type of sheet including a plurality of types of fibers to be dehydrated, but the vertical wire is generally 0.12 to 0. .24 mm, preferably 0.14 to 0.22 mm, and more preferably 0.16 to 0.20 mm. When the diameter of the vertical wire is less than 0.12 mm, the strength of the mesh belt tends to decrease, and when it exceeds 0.24 mm, the horizontal wire opening becomes large and the mesh belt becomes hard. There is.
In addition, although the diameter of a vertical wire is based also on a woven structure, it influences the opening of a horizontal wire, and it exists in the tendency for the opening of a horizontal wire to become large, so that the diameter of a vertical wire is large.

In the mesh belt of the dehydrator according to the present disclosure, the diameter of the horizontal wire varies depending on the type of sheet including a plurality of types of fibers to be dehydrated, but the horizontal wire is generally 0.12 to 0. .30 mm, preferably 0.14 to 0.28 mm, and more preferably 0.16 to 0.26 mm. If the diameter of the horizontal wire is less than 0.12 mm, the strength of the mesh belt tends to decrease, and if it exceeds 0.30 mm, the vertical wire opening increases and the mesh belt becomes hard. There is.
In addition, although the diameter of a horizontal wire is based also on a woven structure, it influences the opening of a vertical wire, and it exists in the tendency for the opening of a vertical wire to become large, so that the diameter of a horizontal wire is large.

In the present disclosure, the diameter of the vertical wire and the diameter of the horizontal wire are measured as follows.
(1) A Keyence digital microscope VHX-1000 and a mesh belt are prepared in a temperature-controlled room at 20 ° C. and left to stand for 24 hours.
(2) Using the above-mentioned microscope, the diameter of the vertical wire is measured at a total of 100 locations at arbitrary locations.
(3) The average value is adopted as the diameter D _l of the vertical wire.

(4) Using the microscope, the diameter of the horizontal wire is measured at a total of 100 locations at arbitrary locations.
(5) The average value is adopted as the diameter D _c of the horizontal wire.

As the material of the mesh belt, that is, the material of the vertical wire and the horizontal wire, for example, metal, for example, stainless steel, copper and aluminum, synthetic resin, for example, polyester resin, polyolefin resin, for example, polyethylene and polypropylene, polyamide resin, For example, nylon, for example, nylon 6,6, acrylic resin, vinyl resin, for example, polyvinyl chloride, polycarbonate resin, fluororesin, for example, polytetrafluoroethylene and the like can be mentioned.
From the viewpoint of detergency, the mesh belt material is preferably a synthetic resin.

The mesh belt of the dehydrator of the present disclosure preferably has an air permeability of 140 m ³ / m ² / min or more, more preferably 150 m ³ / m ² / min or more, and even more preferably 160 m ³ / m ² / min or more. . If the air permeability is less than 140 m ³ / m ² / min, moisture contained in the sheet may not be sucked, and in the embodiment in which dehydration and fiber entanglement are performed simultaneously, In some cases, the degree of entanglement of the fibers decreases.

Although there is no particular upper limit for the air permeability, the air permeability is preferably 480 m ³ / m because, if the air permeability is high, the first fibers may be easily dropped depending on the mesh opening or the like. ² / min or less, more preferably 360 m ³ / m ² / min or less, and even more preferably 300 m ³ / m ² / min or less.

The air permeability is measured as follows using a KES-F8-AP1 air permeability tester manufactured by Kato Tech Co., Ltd.
(1) The KES-F8-AP1 breathability tester and the sample are allowed to stand in a constant temperature room at 20 ° C. for 24 hours.
(2) The ventilation resistance value of the sample is measured at a piston speed of 2 cm / second.
(3) The above measurement is repeated five times, and the average value is adopted as the ventilation resistance value AR (kPa · s / m) of the sample.
(4) The ventilation resistance value AR is calculated by the following formula:
AP (m ³ / m ² /min)=7.473/AR
According to the above, the air permeability is converted into AP (m ³ / m ² / min).

  The air permeability is a value that serves as an index of water permeability of the mesh belt during dehydration, that is, the liquid permeability of the mesh belt. This is because water and ambient air are sucked together from the suction unit during dehydration.

Specific examples of the weaving structure of the mesh belt of the dehydrator according to the present disclosure include twill weave (twill weave), torn twill weave, satin weave, and the like. A twill weave with a horizontal wire floating, a broken twill weave with a horizontal wire floating on the surface, and a satin weave with a horizontal wire floating on the surface are preferred. This is because in the woven structure in which the vertical wire is floated on the surface, the horizontal wire is floated on the back surface, which makes it difficult to clean the vertical wire on the back surface of the mesh belt.
In addition, the torn slash is different from the twill weave in which the slashes in the diagonal direction are broken (broken) in the middle.

  Here, the detergency of the mesh belt having a structure having a vertical wire on the surface will be described. FIG. 12 is a diagram showing an organization chart of a mesh belt having a woven structure with a four-tear pattern that has a vertical-slanted pattern. The mesh belt 2 shown in FIG. 12 has a vertical wire 21 floating on the front surface 3 side and a horizontal wire 22 floating on the back surface 4 side. Note that the mesh belt 2 shown in FIG. 12 corresponds to the mesh belt 2 shown in FIG.

  13 is a view for explaining a state in which the mesh belt 2 shown in FIG. 12 is cleaned by the back surface cleaning brush 8 ′, and corresponds to a cross-sectional view in the orthogonal direction CD in the XIII-XIII cross section of FIG. .

  In the mesh belt 2 shown in FIG. 13, the first fiber (not shown) on the vertical wire attached to the vertical wire 21 is removed by the tip of the back surface cleaning brush 8 ′ contacting the vertical wire 21. The In the mesh belt 2 shown in FIG. 13, the horizontal wire 22 repeatedly crosses one vertical wire 21 on the front surface 3 side and then crosses three vertical wires 21 on the back surface 4 side. Therefore, 3/4 of the vertical wire 21, that is, 75%, the horizontal wire 22 exists on the back surface 4 side, so that the vertical wire 21 is not easily cleaned by the back surface cleaning brush 8 ′.

  In the mesh belt 2 shown in FIG. 2 (FIG. 5), 1/4 of the vertical wire 21, that is, 25%, the horizontal wire 22 exists on the back surface 4 side. 'Easy to be washed.

  In the dehydrator of the present disclosure, the conveyance speed of the mesh belt can be adopted without limitation as the conveyance speed used when dehydrating a sheet in the art, for example, 60 to 170 m / min, and preferably Is a conveyance speed of 80 to 150 m / min.

  In the dehydrator of the present disclosure, the suction pressure of the suction unit varies depending on the type of sheet including a plurality of types of fibers, but the suction unit is generally 3 to 40 kPa, and preferably 5 to 30 kPa, at the suction port. Having a suction pressure of If the suction pressure exceeds 40 kPa, the rate at which the first fibers drop off from the sheet may increase, and if the suction pressure falls below 3 kPa, the efficiency of dehydration may decrease.

  In the dehydrator of the present disclosure, the moving speed of the mesh belt is not particularly limited, and the moving speed is generally 60 to 170 m / min, and preferably 80 to 150 m / min. When the moving speed exceeds 170 m / min, the sheet tends to be insufficiently dehydrated, and when the moving speed is less than 60 m / min, the efficiency of dehydration tends to decrease.

  FIG. 14 is a perspective view showing a dehydrator according to another embodiment of the present disclosure. The dehydrator 1 shown in FIG. 14 has a water spray unit 41 for entanglement of fibers of a sheet (not shown) including a plurality of types of fibers in the upper part of the suction unit 7 ′ with the mesh belt 2 interposed therebetween. And a water spraying unit 41 ″ above the suction unit 7 ″. More specifically, the water spraying units 41 ′ and 41 ″ are disposed above the suction ports 7′A and 7 ″ A, respectively, of the suction units 7 ′ and 7 ″. By disposing the water spray unit on the upper part of the suction unit, water is sucked from the sheet while the fibers of the sheet containing plural kinds of fibers are entangled by the sprayed water.

  If the water sprayed from the water spray unit continues to remain in the sheet, the energy of the water stream sprayed thereafter is relaxed by the remaining water, and the entanglement degree of the sheet may be uneven. The dehydrator of the present disclosure dehydrates the sheet while cleaning dirt adhering to the mesh belt. Therefore, when water is sucked by the suction unit, non-uniformity of the dehydration degree is less likely to occur in the sheet, and the entanglement degree of the sheet Inhomogeneity is also unlikely to occur.

  Further, since the dehydrator of the present disclosure dehydrates the sheet while cleaning dirt adhering to the mesh belt, even when dehydrating a sheet containing fibers that are easily detached, the mesh belt due to the adhering fibers is used. It is difficult to clog and the sheet can be dehydrated continuously for a long time.

  In the embodiment shown in FIG. 14, two water spray units are installed on the two suction units, but a dehydrator according to another embodiment of the present disclosure has one water spray unit, And the dehydrator according to another embodiment has three or more water spraying units.

  The water pressure of the water flow sprayed from the water spray unit varies depending on the type, thickness, and the like of the sheet including a plurality of types of fibers to be entangled. The water spray unit preferably has a water pressure of 3.0 to 9.0 MPa, more preferably 3.0 to 7.0 MPa, and even more preferably 3.0 to 5.0 MPa at the outlet of the water spray unit. Spray a stream of water on the sheet.

  If the water pressure is less than 3.0 MPa, the entanglement degree of the sheet to be entangled may be insufficient. When the water pressure exceeds 9.0 MPa, (i) when the sheet to be entangled has a hole, (ii) the degree of entanglement of the sheet to be entangled becomes too high and the formed nonwoven fabric becomes hard and ( iii) The fibers in the sheet may fall off and easily adhere to the mesh belt.

  The water spray unit preferably sprays a water flow onto the sheet at a flow rate of 50 to 600 L / min / m, more preferably 100 to 500 L / min / m, and even more preferably 200 to 400 L / min / m. This is because the sheet is entangled.

  The water spray unit sprays a water flow on the sheet at an interval of preferably 50 cm or less, more preferably 35 cm or less, and even more preferably 20 cm or less. The water spray unit preferably has a plurality of nozzles, and the nozzles preferably have a diameter of 5 mm or less, more preferably 4 mm or less, and even more preferably 3 mm or less. This is because the sheet is entangled.

<Method of dehydrating the sheet>
Next, a method for dehydrating the sheet of the present disclosure (hereinafter, may be abbreviated as “dehydration method”) will be described.
The dehydration method of the present disclosure includes a step of preparing a dehydrator.
Since this step has already been described in the section of “Dehydrator”, a description thereof will be omitted.

  The dehydration method of the present disclosure includes a sheet that includes water, a first fiber having a first average fiber length, and a second fiber having a second average fiber length that is longer than the first average fiber length. Is carried on the mesh belt and sucks water from the suction unit.

It does not restrict | limit especially as a kind of 1st fiber, For example, a natural fiber, a synthetic fiber, and a semi-synthetic fiber are mentioned.
Examples of the natural fiber include pulp and regenerated cellulose.
Examples of the pulp include wood pulp and non-wood pulp. Examples of the wood pulp include softwood pulp and hardwood pulp. Examples of the non-wood pulp include wallet pulp, bagasse pulp, reed pulp, kenaf pulp, mulberry pulp, bamboo pulp, hemp pulp, cotton pulp (for example, cotton linter), and the like.

  In addition, the pulp is related to its production method, such as mechanical pulp, for example, groundwood pulp, refiner ground pulp, thermomechanical pulp, chemithermomechanical pulp, etc., or chemical pulp, such as kraft pulp, sulfide pulp, alkaline pulp, etc. Can be.

Examples of the regenerated cellulose include rayon, for example, viscose rayon obtained from viscose, polynosic and modal, copper ammonia rayon obtained from a copper ammonia salt solution of cellulose (also referred to as “cupra”); organic compound and water Examples thereof include lyocell and tencel obtained by an organic solvent spinning method using an organic solvent which is a mixed solution, and without passing through a cellulose derivative.
Examples of the semi-synthetic fiber include semi-synthetic cellulose such as acetate fiber such as triacetate and diacetate.

  Examples of the synthetic fibers include heat-fusible fibers such as polyolefin polymers such as polyethylene or polypropylene; polyester polymers such as terephthalate polymers such as polyethylene terephthalate (PET), polybutylene terephthalate, and polypenty. Examples include fibers formed from terephthalate; polyamide-based polymers such as nylon 6 or nylon 6,6; acrylic polymers; polyacrylonitrile-based polymers; or modified products thereof, or combinations thereof.

  The heat-fusible fiber is a composite fiber containing a low melting point resin and a high melting point resin having a higher melting point than the low melting point resin, for example, a core-sheath type, a core-sheath eccentric type, and a side-by-side type fiber. It is preferable.

  The first fiber is preferably 0.5 to 5.0 mm, more preferably 0.7 to 4.0 mm, still more preferably 0.9 to 3.0 mm, and more preferably 1.0 to 2.0 mm. Has an average fiber length. This is from the viewpoint of the cleanability of the sheet.

As the type of the second fiber, the same fiber as the above-mentioned first fiber can be mentioned. When a nonwoven fabric is produced from a sheet containing a plurality of types of fibers, the second fiber is the above-mentioned synthetic fiber. In particular, a heat-fusible fiber is preferable.
The second fiber is not particularly limited as long as it has an average fiber length longer than the average fiber length of the first fiber, but is preferably 10 to 100 mm, more preferably 15 to 90 mm, and still more preferably 20 to 20 mm. It has an average fiber length of 70 mm.

  The sheet | seat containing a multiple types of fiber can further contain the 3rd fiber, and the thing similar to a 1st fiber is mentioned as a 3rd fiber, For example, a regenerated cellulose is illustrated.

  As a combination of the first fiber and the second fiber, for example, a combination of pulp and heat-fusible fiber, more specifically, a pulp having an average fiber length of 0.5 to 5.0 mm, The combination with the heat-fusible fiber which has an average fiber length of 100 mm is mentioned.

  As a combination of the first fiber, the second fiber, and the third fiber, for example, a combination of pulp, heat-fusible fiber, and regenerated cellulose, more specifically, an average fiber of 0.5 to 5.0 mm Examples include a combination of a pulp having a length, a heat-fusible fiber having an average fiber length of 10 to 100 mm, and a regenerated cellulose having an average fiber length of 10 to 100 mm.

  The sheet containing a plurality of types of fibers may be a single-layer sheet including a first fiber, a second fiber, and an optional third fiber, and may be a multilayer sheet. .

  Examples of the multi-layer sheet include a sheet composed of three layers, for example, a first layer including a first fiber and an optional third fiber, and disposed on the first layer. A sheet comprising a second layer comprising second fibers and a third layer disposed on the second layer and comprising first fibers and optionally third fibers.

  The sheet containing a plurality of types of fibers to be dehydrated by the dehydrator of the present disclosure may be a fiber entangled, that is, a nonwoven fabric, and a fiber that is not entangled, that is, a web. May be.

The basis weight of the sheet containing a plurality of types of fibers varies depending on the application. For example, when a nonwoven fabric, for example, a nonwoven fabric for wet tissue is manufactured from a sheet containing a plurality of types of fibers, the sheet is, for example, 20 ^{~200g / m 2, 40~150g / m} 2, can have a basis weight of such 50 to 100 g / m ^2.

  In the dehydration method of the present disclosure, the sheet including the plurality of types of fibers is transported on a mesh belt, and the sheet including the plurality of types of fibers is dehydrated by sucking water from the suction unit. For example, as shown in FIG. 15, a sheet 31 containing a plurality of types of fibers is placed on the mesh belt 2 of the dehydrator 1 shown in FIG. 1, and suction ports (7 ′ A, 7 ′) of the suction unit 7 are placed. The sheet 31 containing a plurality of types of fibers can be dehydrated by sucking water from 'A etc.).

  In a dehydration method according to another embodiment of the present disclosure, the dehydrator comprises a water spray unit for entangling at least a second fiber of the sheet at the top of the suction unit with the mesh belt in between, and While sucking water from the suction unit, at least the second fibers are entangled.

<Method for producing nonwoven fabric for wet tissue>
A method for manufacturing a nonwoven fabric for wet tissue according to one embodiment of the present disclosure will be described in relation to the apparatus for manufacturing a nonwoven fabric for wet tissue shown in FIG.

  FIG. 16 is a diagram illustrating an example of a wet tissue nonwoven fabric manufacturing apparatus 101 used in the above manufacturing method. In the manufacturing apparatus 101 shown in FIG. 16, the second fiber and the desired third fiber prepared by a method known in the art are put into the card machine 102 from the feeder to form the web 103. The first fibers prepared by methods known in the art are then deposited on the web 103 from the feeder 104 to form the laminated web 105.

  In parallel with the formation of the laminated web 105, the first fiber and the desired third fiber prepared by a method known in the art are fed from the feeder into the card machine 106 to form the web 107. The web 107 is then stacked on the laminated web 105 to form the laminated web 108.

  The laminated web 108 is moved onto the suction drum 109, while sucking water from the suction drum 109, the water spray unit 110 sprays water on the laminated web 108, entangles the fibers in the laminated web 108, and the nonwoven fabric 111. Get. Next, the nonwoven fabric 111 is moved to the dehydrator 112 to dehydrate moisture in the nonwoven fabric 111. The dehydrator 112 is the same as the dehydrator 1 shown in FIG. 1, and a description of units included in the dehydrator 112 is omitted.

  Next, the nonwoven fabric 111 is moved to the dryer 114, the second fibers are heat-sealed, and the nonwoven fabric 111 that has been heat-sealed is wound up with a roll 115, thereby completing the nonwoven fabric for wet tissue. Next, the wet tissue is manufactured by cutting the nonwoven fabric for wet tissue by a method known in the art and impregnating a chemical solution known in the art.

Hereinafter, although an example is given and this indication is explained, this indication is not limited to these examples.
[Example 1]
A wet tissue nonwoven fabric manufacturing apparatus 101 shown in FIG. 1 was produced. The manufacturing method will be described using the reference numerals shown in FIG.

A composite fiber having an average fiber length of about 40 mm as the second fiber and a rayon having an average fiber length of about 45 mm as the third fiber are put into the card machine 102 from the feeder, and the basis weight is 15 g. A web 103 of / m ² was formed. The composite fiber was polyethylene terephthalate having a melting point of about 130 ° C. and a core / sheath type composite fiber of polyethylene having a melting point of about 165 ° C.

Subsequently, softwood pulp having an average fiber length of about 1.6 mm was stacked on the web 103 so as to have a basis weight of 15 g / m ² to form a laminated web 105. A composite fiber having an average fiber length of about 40 mm as the second fiber and a rayon having an average fiber length of about 45 mm as the third fiber are put into the card machine 106 from the feeder, and the basis weight is 15 g. / M ² web 107 was formed and stacked on laminated web 105 to form laminated web 108.

Next, the laminated web 108 is moved onto the suction drum 109 and a water flow (water pressure: 5.0 MPa, flow rate: 400 L / min / m, from the water spray unit 110 to the laminated web 108 while sucking water with the suction drum. (Interval: 5 cm, nozzle diameter: 3 mm) was sprayed to entangle the fibers in the laminated web 108 to obtain a nonwoven fabric 111.
Subsequently, the nonwoven fabric 111 was moved to the dehydrator 112, and water was sucked from the suction unit with a suction pressure of 30 kPa to dehydrate the inside of the nonwoven fabric 111.

Note that the mesh belt 113 has a complete structure of a four-sheet broken oblique line formed of a vertical wire having a diameter of about 0.20 mm and a horizontal wire having a diameter of about 0.22 mm, and the surface shown in FIG. It was arranged to become. The vertical wire opening and the horizontal wire opening were about 0.080 mm and about 0.250 mm, respectively. Further, the air permeability of the mesh belt was 160 m ³ / m ² / min.

The water stream sprayed from the mesh belt water spray section has a water pressure of 5.0 MPa and a flow rate of 40 L / min / m, and the mesh belt water spray section has a plurality of nozzles (diameter: 3 mm). The mesh belt had a distance of 20 cm.
Further, the water flow sprayed from the surface roll water spraying portions 14 ′ and 14 ″ has a water pressure of 5.0 MPa and a flow rate of 40 L / min / m, respectively, and the water spraying portion 14 ′ for the surface roll. And 14 ″ each had a plurality of nozzles (diameter: 3 mm) and had a surface roll and a spacing of 20 cm.

Next, the nonwoven fabric 111 is moved to a drier 114 maintained at 150 ° C., the second fibers are heat-sealed, and the heat-sealed nonwoven fabric 111 is wound up by a roll 115, whereby a wet tissue nonwoven fabric No. . 1 was obtained. Non-woven fabric for wet tissue The basis weight of 1 was 45 g / m ² .

  Using the mesh belt, a nonwoven fabric for wet tissue No. The production of No. 1 was continued for about one month, but there was hardly any adhesion of the first fibers to the mesh belt.

[Example 2]
Except for replacing the front and back of the mesh belt 113, the nonwoven fabric for wet tissue No. 1 was produced.
As a result, in about 4 hours, the mesh belt was clogged with the first fibers. The production of No. 1 could not be continued.

[Example 3]
Except that the woven structure of the mesh belt 113 is changed to a woven structure of a weft-slanted weave (4 slashes) having the complete structure 24 shown in FIG. Non-woven fabric for wet tissue No. 1 was produced. Note that the complete structure 24 shown in FIG. 17 is formed of the vertical wire 21 and the horizontal wire 22, the upper direction is the conveyance direction MD, the left and right are the orthogonal directions CD, and the front is the surface 3. .

The mesh belt had a vertical wire opening, horizontal wire opening and air permeability substantially equal to those of the mesh belt of Example 1.
Using the mesh belt, the wet tissue nonwoven fabric No. When 1 was manufactured, the first fiber hardly adhered to the mesh belt.

[Example 4]
Nonwoven fabric for wet tissue No. 1 in the same manner as in Example 1 except that the woven structure of the mesh belt 113 is changed to a weft satin type five satin woven structure having the complete structure 24 shown in FIG. . 1 was produced. Note that the complete structure 24 shown in FIG. 18 is formed of the vertical wire 21 and the horizontal wire 22, the upper direction is the transport direction MD, the left and right are the orthogonal directions CD, and the front is the surface 3. .

  Using the mesh belt, the wet tissue nonwoven fabric No. When 1 was manufactured, the first fiber hardly adhered to the mesh belt.

[Example 5]
Except for changing the woven structure of the mesh belt 113 to a plain woven structure, a nonwoven fabric for wet tissue No. 1 was obtained in the same manner as in Example 1. 1 was produced. The vertical and horizontal wire openings of the mesh belt having a plain weave structure are about 0.17 mm and about 0.22 mm, respectively, and the air permeability is 135 m ³ / m ² / min. It was.

  As a result, in about 4 hours, the mesh belt was clogged with the first fibers. The production of No. 1 could not be continued. Further, the degree of sheet dehydration was low due to the low air permeability.

The present disclosure relates to the following J1 to J19.
[J1]
A dehydrator for a sheet comprising: a first fiber having a first average fiber length; and a second fiber having a second average fiber length longer than the first average fiber length,
The dehydrator
(I) A mesh belt for transporting the sheet placed thereon, having a front surface on the sheet side and a back surface on the opposite side, and a transport area for transporting the sheet, and the mesh belt To wash the washing area and pass through the mesh belt,
(Ii) a suction unit that is disposed below the mesh belt in the transport area and has a suction port for sucking moisture contained in the sheet through the mesh belt; and (iii) the transport area and / or the above A cleaning unit for cleaning the mesh belt disposed in the cleaning area;
And the mesh belt has a woven structure formed from a plurality of vertical wires extending in the sheet conveying direction and a plurality of horizontal wires extending in a direction orthogonal to the sheet conveying direction, and In the woven structure, the horizontal wire on the front side returns to the front side after traversing one vertical wire on the back side,
The dehydrator as described above.

[J2]
The dehydrator according to J1, wherein in the woven structure, the horizontal wire on the back side returns to the back side after traversing two or more vertical wires on the front side.
[J3]
The dehydrator according to J1 or J2, wherein in the woven structure, the vertical wire on the back side returns to the back side after traversing one horizontal wire on the front side.

[J4]
The dehydrator according to any one of J1 to J3, wherein in the woven structure, the vertical wire on the front surface side crosses two or more horizontal wires on the back surface side and then returns to the front surface side.
[J5]
The dehydrator according to any one of J1 to J4, wherein the woven structure has a complete structure of 3 × 3 to 10 × 10.

[J6]
The dehydrator according to any one of J1 to J5, wherein the mesh belt has a tissue point density of 1/10 to 1/3 on a surface thereof.
[J7]
The dehydrator according to any one of J1 to J6, wherein in the woven structure, less than four structural points are continuous in an oblique direction.

[J8]
Dehydration according to any one of J1 to J7, wherein the opening of the vertical wire is in the range of 0.050 to 0.140 mm, and the opening of the horizontal wire is larger than the opening of the vertical wire. Machine.
[J9]
The dehydrator according to any one of J1 to J8, wherein the mesh belt has an air permeability of 140 to 480 m ³ / m ² / min.

[J10]
The dehydrator according to any one of J1 to J9, wherein the woven structure is torn and has a complete structure of torn.
[J11]
Any one of J1 to J10, wherein the first fiber is a pulp having an average fiber length of 0.5 to 5.0 mm, and the second fiber is a synthetic fiber having an average fiber length of 10 to 100 mm. The dehydrator described in the item.

[J12]
The dehydrator according to any one of J1 to J11, wherein the dehydrator has a water spraying unit for entangling at least a second fiber at an upper part of the suction unit with the mesh belt interposed therebetween. .

[J13]
A method of dehydrating a sheet comprising a first fiber having a first average fiber length and a second fiber having a second average fiber length longer than the first average fiber length,
A step of preparing the dehydrator according to any one of J1 to J12, a step of transporting the sheet containing water on the mesh belt, and sucking water from the suction unit;
Including the above method.

[J14]
The dehydrator has a water spray unit for entangling at least a second fiber of the sheet at the upper part of the suction unit with the mesh belt interposed therebetween, and sucks water from the suction unit. However, the method according to J13, wherein water is sprayed from the water spray unit to the sheet, and at least the second fibers are entangled.

[J15]
A method of manufacturing a nonwoven fabric for wet tissue,
Providing a sheet comprising a first fiber having a first average fiber length and a second fiber having a second average fiber length longer than the first average fiber length;
Preparing the dehydrator according to any one of J1 to J12;
Transporting the sheet containing water on the mesh belt and sucking water from the suction unit;
Including the above method.

[J16]
The method of J15, further comprising spraying water onto the sheet from the water spray unit to entangle at least a second fiber.
[J17]
The method according to J16, wherein the entanglement step is performed before the water suction step.

[J18]
The method according to J16, wherein the entanglement step is performed simultaneously with the water suction step.
[J19]
In any one of J15 to J18, the second fiber includes a heat-fusible fiber, and includes a step of heating the sheet and heat-sealing the second fiber after the step of sucking the water. The method described.

The present disclosure also relates to the following K1 to K36, L1 to L36, and M1 to M40.
[K1]
A dehydrator for a sheet comprising: a first fiber having a first average fiber length; and a second fiber having a second average fiber length longer than the first average fiber length,
The dehydrator
(I) A mesh belt for transporting the sheet placed thereon, having a front surface on the sheet side and a back surface on the opposite side, and a transport area for transporting the sheet, and the mesh belt To wash the washing area and pass through the mesh belt,
(Ii) a suction unit that is disposed below the mesh belt in the transport area and has a suction port for sucking moisture contained in the sheet through the mesh belt; and (iii) the transport area and / or the above A cleaning unit for cleaning the mesh belt disposed in the cleaning area;
And the mesh belt has a woven structure formed from a plurality of vertical wires extending in the sheet conveying direction and a plurality of horizontal wires extending in a direction orthogonal to the sheet conveying direction, and In the woven structure, the horizontal wire on the front side returns to the front side after traversing one vertical wire on the back side,
The dehydrator as described above.

[K2]
The dehydrator according to K1, wherein in the woven structure, the horizontal wire on the back surface side returns to the back surface side after traversing two or more vertical wires on the front surface side.
[K3]
The dehydrator according to K1 or K2, wherein in the woven structure, the vertical wire on the back side returns to the back side after traversing one horizontal wire on the front side.

[K4]
The dehydrator according to any one of K1 to K3, wherein in the woven structure, the vertical wire on the front side returns to the front side after traversing two or more horizontal wires on the back side.
[K5]
The dehydrator according to any one of K1 to K4, wherein the woven structure has a complete structure of 3 × 3 to 10 × 10.

[K6]
The dehydrator according to any one of K1 to K5, wherein the mesh belt has a tissue point density of 1/10 to 1/3 on a surface thereof.

[K7]
The dehydrator according to any one of K1 to K6, wherein in the woven structure, less than four structural points are continuous in an oblique direction.
[K8]
Dehydration according to any one of K1 to K7, wherein the opening of the vertical wire is in the range of 0.050 to 0.140 mm, and the opening of the horizontal wire is larger than the opening of the vertical wire. Machine.

[K9]
The dehydrator according to any one of K1 to K8, wherein the mesh belt has an air permeability of 140 to 480 m ³ / m ² / min.
[K10]
The dehydrator according to any one of K1 to K9, wherein the woven structure is torn and has a complete structure of torn.

[K11]
The dehydrator according to any one of K1 to K10, wherein the dehydrator has a water spraying unit for entangling at least a second fiber at an upper part of the suction unit with the mesh belt interposed therebetween. .
[K12]
The dehydrator according to any one of K1 to K11, wherein the first fiber is a natural fiber.

[K13]
The dehydrator according to any one of K1 to K12, wherein the first fiber is pulp.
[K14]
The dehydrator according to any one of K1 to K13, wherein the first fibers have an average fiber length of 0.5 to 5.0 mm.

[K15]
The dehydrator according to any one of K1 to K14, wherein the second fiber is a synthetic fiber.
[K16]
The dehydrator according to any one of K1 to K15, wherein the second fiber is a heat-fusible fiber.
[K17]
The dehydrator according to any one of K1 to K16, wherein the second fibers have an average fiber length of 10 to 100 mm.

[K18]
The dehydrator according to any one of K1 to K17, wherein the sheet further includes a third fiber.
[K19]
The dehydrator according to K18, wherein the third fiber is a natural fiber.
[K20]
The dehydrator according to K18 or K19, wherein the third fiber is regenerated cellulose.

[K21]
The dehydrator according to any one of K18 to K20, wherein the third fiber has an average fiber length of 10 to 100 mm.
[K22]
The dehydrator according to any one of K1 to K21, wherein the sheet is a sheet composed of one layer.

[K23]
The dehydrator according to any one of K1 to K22, wherein the sheet includes a first layer, a second layer, and a third layer in that order.
[K24]
The dehydrator according to any one of K1 to K23, wherein the second layer includes first fibers.

[K25]
The dehydrator according to any one of K1 to K24, wherein the first layer and / or the third layer includes a second fiber.
[K26]
The dehydrator according to any one of K1 to K25, wherein the first layer and / or the third layer further includes a third fiber.

[K27]
The sheet has a basis weight of 20 to 200 g / m ^2, dehydrator according to any one of K1～K26.
[K28]
Any one of K1 to K27, wherein the cleaning unit includes a back surface cleaning unit for removing the first fibers attached to the mesh belt from the back surface side of the mesh belt disposed in the transport area. The dehydrator described in the item.

[K29]
The back surface cleaning unit includes a back surface cleaning brush, and the back surface cleaning brush is a fixed brush or a rotatable brush having a rotation axis in a direction intersecting the transport direction, and the brush The dehydrator according to K28, wherein the tip is in contact with the back surface.
[K30]
The dehydrator includes a plurality of suction units, and the back surface cleaning unit is disposed between the first suction unit and the second suction unit, counting from the upstream side of the transfer area. , K28 or K29.

[K31]
The said washing | cleaning unit is provided with the surface washing | cleaning unit for removing the 1st fiber adhering to the said mesh belt from the said surface side of the said mesh belt in the said washing | cleaning area, It is any one of K1-K30. Dehydrator.
[K32]
The surface cleaning unit includes a surface cleaning brush, and the surface cleaning brush is a fixed brush or a rotatable brush having a rotation axis in a direction intersecting the transport direction, and the brush The dehydrator according to K31, wherein the tip is in contact with the surface.

[K33]
The mesh belt is an endless mesh belt, and the mesh belt is disposed in the cleaning area, the plurality of back rolls in contact with the back surface of the mesh belt, and the one or more surfaces in contact with the surface of the mesh belt. The dehydrator according to any one of K1 to K32, which includes a surface roll cleaning unit that is transported by a roll and the cleaning unit removes the first fibers attached to the surface roll.

[K34]
The dehydrator according to K33, wherein the surface roll cleaning unit includes a surface roll water spray unit that sprays water onto the surface roll, and a roll cleaning brush that cleans the surface roll.
[K35]
The dehydration according to K33 or K34, wherein the surface roll cleaning unit includes a mesh belt water spray unit that sprays water on the back surface of the mesh belt, which is disposed upstream of the surface roll cleaning unit in the transport direction. Machine.

[K36]
The dehydrator according to any one of K33 to K35, wherein the dehydrator includes two or more surface rolls, and the cleaning unit includes a surface roll cleaning unit at least at the two surface rolls.

[L1]
A method of dehydrating a sheet comprising a first fiber having a first average fiber length and a second fiber having a second average fiber length longer than the first average fiber length,
Preparing a dehydrator comprising the following (i) to (iii):
(I) A mesh belt for transporting the sheet placed thereon, having a front surface on the sheet side and a back surface on the opposite side, and a transport area for transporting the sheet, and the mesh belt To wash the washing area and pass through the mesh belt,
(Ii) a suction unit that is disposed below the mesh belt in the transport area and has a suction port for sucking moisture contained in the sheet through the mesh belt; and (iii) the transport area and / or the above A cleaning unit for cleaning the mesh belt disposed in the cleaning area;
Here, the mesh belt has a woven structure formed from a plurality of vertical wires extending in the sheet conveyance direction and a plurality of horizontal wires extending in an orthogonal direction orthogonal to the sheet conveyance direction, and In the woven structure, the horizontal wire on the front side returns to the front side after traversing one vertical wire on the back side, and transports the sheet containing water on the mesh belt, Sucking water from the suction unit;
Including the above method.

[L2]
The method according to L1, wherein in the woven structure, the horizontal wire on the back surface side returns to the back surface side after traversing two or more vertical wires on the front surface side.
[L3]
The method according to L1 or L2, wherein in the woven structure, the vertical wire on the back side returns to the back side after traversing one horizontal wire on the front side.

[L4]
The method according to any one of L1 to L3, wherein in the woven structure, the vertical wire on the front surface side returns to the front surface side after traversing two or more horizontal wires on the back surface side.
[L5]
The method according to any one of L1 to L4, wherein the woven structure has a complete structure of 3 × 3 to 10 × 10.

[L6]
The method according to any one of L1 to L5, wherein the mesh belt has a tissue point density of 1/10 to 1/3 on a surface thereof.
[L7]
The method according to any one of L1 to L6, wherein in the woven structure, less than four texture points are continuous in an oblique direction.

[L8]
The method according to any one of L1 to L7, wherein the opening of the vertical wire is in a range of 0.050 to 0.140 mm, and the opening of the horizontal wire is larger than the opening of the vertical wire. .
[L9]
The method according to any one of L1 to L8, wherein the mesh belt has an air permeability of 140 to 480 m ³ / m ² / min.

[L10]
The method according to any one of L1 to L9, wherein the woven structure has a complete structure with four pieces of tearing.
[L11]
The method according to any one of L1 to L10, wherein the dehydrator includes a water spraying unit for entangling at least a second fiber at an upper portion of the suction unit with the mesh belt interposed therebetween.

[L12]
The method according to any one of L1 to L11, wherein the first fiber is a natural fiber.
[L13]
The method as described in any one of L1-L12 whose 1st fiber is a pulp.
[L14]
The method according to any one of L1 to L13, wherein the first fibers have an average fiber length of 0.5 to 5.0 mm.

[L15]
The method according to any one of L1 to L14, wherein the second fiber is a synthetic fiber.
[L16]
The method according to any one of L1 to L15, wherein the second fiber is a heat-fusible fiber.
[L17]
The method according to any one of L1 to L16, wherein the second fibers have an average fiber length of 10 to 100 mm.

[L18]
The method according to any one of L1 to L17, wherein the sheet further includes a third fiber.
[L19]
The method of L18, wherein the third fiber is a natural fiber.
[L20]
The method according to L18 or L19, wherein the third fiber is regenerated cellulose.

[L21]
The method according to any one of L18 to L20, wherein the third fiber has an average fiber length of 10 to 100 mm.
[L22]
The method according to any one of L1 to L21, wherein the sheet is a sheet composed of one layer.

[L23]
The method according to any one of L1 to L22, wherein the sheet includes a first layer, a second layer, and a third layer in that order.
[L24]
The method according to any one of L1-L23, wherein the second layer comprises a first fiber.

[L25]
The method according to any one of L1 to L24, wherein the first layer and / or the third layer comprises a second fiber.
[L26]
The method according to any one of L1 to L25, wherein the first layer and / or the third layer further comprises a third fiber.

[L27]
The sheet has a basis weight of 20 to 200 g / m ^2, The method according to any one of L1～L26.
[L28]
Any one of L1 to L27, wherein the cleaning unit includes a back surface cleaning unit for removing the first fibers attached to the mesh belt from the back surface side of the mesh belt disposed in the transport area. The method according to item.

[L29]
The back surface cleaning unit includes a back surface cleaning brush, and the back surface cleaning brush is a fixed brush or a rotatable brush having a rotation axis in a direction intersecting the transport direction, and the brush The method of L28, wherein the tip is in contact with the back surface.
[L30]
The dehydrator includes a plurality of suction units, and the back surface cleaning unit is disposed between the first suction unit and the second suction unit, counting from the upstream side of the transfer area. , L28 or L29.

[L31]
The said washing | cleaning unit is equipped with the surface washing | cleaning unit for removing the 1st fiber adhering to the said mesh belt from the said surface side of the said mesh belt in the said washing | cleaning area, It is any one of L1-L30. the method of.
[L32]
The surface cleaning unit includes a surface cleaning brush, and the surface cleaning brush is a fixed brush or a rotatable brush having a rotation axis in a direction intersecting the transport direction, and the brush The method of L31, wherein the tip is in contact with the surface.

[L33]
The mesh belt is an endless mesh belt, and the mesh belt is disposed in the cleaning area, the plurality of back rolls in contact with the back surface of the mesh belt, and the one or more surfaces in contact with the surface of the mesh belt. The method as described in any one of L1-L32 provided with the surface roll washing | cleaning unit for removing the 1st fiber conveyed by the roll and the said washing | cleaning unit adhering to the said surface roll.

[L34]
The method according to L33, wherein the surface roll cleaning unit includes a surface roll water spray unit that sprays water onto the surface roll, and a roll cleaning brush that cleans the surface roll.
[L35]
The method according to L33 or L34, wherein the surface roll cleaning unit includes a mesh belt water spray unit that sprays water on the back surface of the mesh belt, which is disposed upstream of the surface roll cleaning unit in the transport direction. .

[L36]
The method according to any one of L33 to L35, wherein the dehydrator includes two or more of the surface rolls, and the cleaning unit includes a surface roll cleaning unit at at least two of the surface rolls.

[M1]
A method of manufacturing a nonwoven fabric for wet tissue,
Providing a sheet comprising a first fiber having a first average fiber length and a second fiber having a second average fiber length longer than the first average fiber length;
Preparing a dehydrator comprising the following (i) to (iii):
(I) A mesh belt for transporting the sheet placed thereon, having a front surface on the sheet side and a back surface on the opposite side, and a transport area for transporting the sheet, and the mesh belt To wash the washing area and pass through the mesh belt,
(Ii) a suction unit that is disposed below the mesh belt in the transport area and has a suction port for sucking moisture contained in the sheet through the mesh belt; and (iii) the transport area and / or the above A cleaning unit for cleaning the mesh belt disposed in the cleaning area;
Here, the mesh belt has a woven structure formed from a plurality of vertical wires extending in the sheet conveyance direction and a plurality of horizontal wires extending in an orthogonal direction orthogonal to the sheet conveyance direction, and In the woven structure, the horizontal wire on the surface side returns to the surface side after traversing one vertical wire on the back side,
Transporting the sheet containing water on the mesh belt and sucking water from the suction unit;
Including the above method.

[M2]
The method according to M1, wherein in the woven structure, the horizontal wire on the back surface side returns to the back surface side after traversing two or more vertical wires on the front surface side.
[M3]
The method according to M1 or M2, wherein in the woven structure, the vertical wire on the back side returns to the back side after traversing one horizontal wire on the front side.

[M4]
The method according to any one of M1 to M3, wherein in the woven structure, the vertical wire on the front side returns to the front side after traversing two or more horizontal wires on the back side.
[M5]
The method according to any one of M1 to M4, wherein the woven structure has a complete structure of 3 × 3 to 10 × 10.

[M6]
The method according to any one of M1 to M5, wherein the mesh belt has a tissue point density of 1/10 to 1/3 on a surface thereof.
[M7]
The method according to any one of M1 to M6, wherein in the woven structure, less than four texture points are continuous in an oblique direction.

[M8]
The method according to any one of M1 to M7, wherein the opening of the vertical wire is in a range of 0.050 to 0.140 mm, and the opening of the horizontal wire is larger than the opening of the vertical wire. .
[M9]
The method according to any one of M1 to M8, wherein the mesh belt has an air permeability of 140 to 480 m ³ / m ² / min.

[M10]
The method according to any one of M1 to M9, wherein the woven structure has a complete structure with four pieces of tearing.
[M11]
The method according to any one of M1 to M10, wherein the dehydrator includes a water spraying unit for entangling at least a second fiber at an upper portion of the suction unit with the mesh belt interposed therebetween.

[M12]
The method according to any one of M1 to M11, wherein the first fiber is a natural fiber.
[M13]
The method according to any one of M1 to M12, wherein the first fiber is pulp.

[M14]
The method according to any one of M1 to M13, wherein the first fibers have an average fiber length of 0.5 to 5.0 mm.
[M15]
The method according to any one of M1 to M14, wherein the second fiber is a synthetic fiber.

[M16]
The method according to any one of M1 to M15, wherein the second fiber is a heat-fusible fiber.
[M17]
The method according to any one of M1 to M16, wherein the second fibers have an average fiber length of 10 to 100 mm.

[M18]
The method according to any one of M1 to M17, wherein the sheet further comprises a third fiber.
[M19]
The method of M18, wherein the third fiber is a natural fiber.
[M20]
The method according to M18 or M19, wherein the third fiber is regenerated cellulose.

[M21]
The method according to any one of M18 to M20, wherein the third fiber has an average fiber length of 10 to 100 mm.
[M22]
The method according to any one of M1 to M21, wherein the sheet is a sheet composed of one layer.

[M23]
The method according to any one of M1 to M22, wherein the sheet includes a first layer, a second layer, and a third layer in that order.
[M24]
The method according to any one of M1-M23, wherein the second layer comprises first fibers.

[M25]
The method according to any one of M1-M24, wherein the first layer and / or the third layer comprises a second fiber.
[M26]
The method according to any one of M1-M25, wherein the first layer and / or the third layer further comprises a third fiber.

[M27]
The sheet has a basis weight of 20 to 200 g / m ^2, The method according to any one of M1～M26.
[M28]
Any one of M1 to M27, wherein the cleaning unit includes a back surface cleaning unit for removing the first fibers attached to the mesh belt from the back surface side of the mesh belt disposed in the transport area. The method according to item.

[M29]
The back surface cleaning unit includes a back surface cleaning brush, and the back surface cleaning brush is a fixed brush or a rotatable brush having a rotation axis in a direction intersecting the transport direction, and the brush The method according to M28, wherein the tip is in contact with the back surface.
[M30]
The dehydrator includes a plurality of suction units, and the back surface cleaning unit is disposed between the first suction unit and the second suction unit, counting from the upstream side of the transfer area. , M28 or M29.

[M31]
The said washing | cleaning unit is equipped with the surface washing | cleaning unit for removing the 1st fiber adhering to the said mesh belt from the said surface side of the said mesh belt in the said washing | cleaning area, It is any one of M1-M30. the method of.
[M32]
The surface cleaning unit includes a surface cleaning brush, and the surface cleaning brush is a fixed brush or a rotatable brush having a rotation axis in a direction intersecting the transport direction, and the brush The method of M31, wherein the tip is in contact with the surface.

[M33]
The mesh belt is an endless mesh belt, and the mesh belt is disposed in the cleaning area, the plurality of back rolls in contact with the back surface of the mesh belt, and the one or more surfaces in contact with the surface of the mesh belt. The method as described in any one of M1-M32 provided with the surface roll washing | cleaning unit for removing the 1st fiber conveyed by the roll and the said washing | cleaning unit adhering to the said surface roll.

[M34]
The method according to M33, wherein the surface roll cleaning unit includes a surface roll water spray unit that sprays water onto the surface roll, and a roll cleaning brush that cleans the surface roll.
[M35]
The method according to M33 or M34, wherein the surface roll cleaning unit includes a water spray portion for a mesh belt, which is disposed on the upstream side in the transport direction of the surface roll cleaning unit and sprays water on the back surface of the mesh belt. .

[M36]
The method according to any one of M33 to M35, wherein the dehydrator includes two or more surface rolls, and the cleaning unit includes a surface roll cleaning unit at least two surface rolls.
[M37]
The method according to any one of M1 to M36, further comprising the step of spraying water on the sheet from the water spray unit to entangle the at least second fiber.

[M38]
The method of M37, wherein the entanglement step is performed prior to the water aspiration step.
[M39]
The method of M37, wherein the entanglement step is performed simultaneously with the water aspirating step.

[M40]
The second fiber includes a heat-fusible fiber, and after the step of sucking the water, the sheet is heated and the second fiber is heat-fused. The method described.

DESCRIPTION OF SYMBOLS 1 Dehydrator 2 Mesh belt 3 Front surface 4 Back surface 5 Transport area 6 Cleaning area 7 Suction unit 7'A, 7''A Suction port 8 Back surface cleaning unit 8 'Back surface cleaning brush 9 Front surface cleaning unit 9' Front surface cleaning brush 10 Back surface roll DESCRIPTION OF SYMBOLS 11 Surface roll 12 Surface roll washing | cleaning unit 13 Roll washing brush 14 Water spray part for surface rolls 15 Water spray part for mesh belts 21 Vertical wire material 22 Horizontal wire material 23 Weave structure 24 Complete structure 25 The arch part which protrudes on the surface side 26 It protrudes on the back side Arch portion 27 texture point 28 non-texture point 31 sheet containing plural kinds of fibers 32 first fiber on vertical wire 33 first fiber on horizontal wire 41 water spraying unit 101 manufacturing apparatus 102, 106 card machine 103 , 107 Web 104 Feeder 105, 108 Laminated web 109 Suction drum 110 Water spray unit 111 Non-woven fabric 112 Dehydrator 113 Mesh belt 114 Dryer 115 Roll

Claims (15)

A dehydrator for a sheet comprising: a first fiber having a first average fiber length; and a second fiber having a second average fiber length longer than the first average fiber length,
The dehydrator
(I) A mesh belt for carrying the sheet thereon and conveying the sheet, having a front surface on the sheet side and a back surface on the opposite side, and a conveyance area for conveying the sheet, and the mesh belt To wash the washing area and pass through the mesh belt,
(Ii) a suction unit that is disposed under the mesh belt in the transport area and has a suction port for sucking moisture contained in the sheet through the mesh belt;
(Iii-1) a surface cleaning unit arranged in the cleaning area for removing first fibers attached to the mesh belt from the surface side of the mesh belt, and (iii-2) in the transport area A back surface cleaning unit for removing the first fibers attached to the mesh belt from the back surface side of the mesh belt, the back surface cleaning unit comprising a back surface cleaning brush;
With
The mesh belt has a woven structure formed from a plurality of vertical wires extending in the sheet conveying direction and a plurality of horizontal wires extending in a direction orthogonal to the sheet conveying direction, and in the woven structure The horizontal wire on the surface side returns to the front side after traversing one vertical wire on the back side, and the horizontal wire returned to the front side has two or more vertical wires on the front side. Back to the back side after crossing
The dehydrator characterized by the above.   The dehydrator according to claim 1, wherein the back surface cleaning brush is a fixed brush or a rotatable brush having a rotation axis in a direction intersecting the transport direction.   The dehydrator according to claim 1 or 2, wherein the back surface cleaning unit further includes a water spray unit that sprays water onto the mesh belt.   The dehydrator according to any one of claims 1 to 3, wherein the back surface cleaning brush is disposed after the suction unit.   The dehydrator further includes a surface roll in contact with the surface of the mesh belt, and the surface cleaning unit supplies water to the back surface of the mesh belt disposed upstream of the surface roll in the transport direction. The dehydrator according to claim 4, further comprising a mesh belt water spray unit for spraying.   The dehydrator according to claim 5, wherein the surface cleaning unit further includes a surface roll water spray unit that sprays water onto the surface roll, and a roll cleaning brush that cleans the surface roll.   The dehydrator according to any one of claims 1 to 6, wherein in the woven structure, the vertical wire on the back surface side returns to the back surface side after traversing one horizontal wire on the front surface side.   The dehydrator according to any one of claims 1 to 7, wherein in the woven structure, the vertical wire on the front side returns to the front side after traversing two or more horizontal wires on the back side.   The dehydrator according to any one of claims 1 to 8, wherein the woven structure has a complete structure of 3x3 to 10x10.   The dehydrator according to any one of claims 1 to 9, wherein the mesh belt has a tissue point density of 1/10 to 1/3 on the surface.   The dehydrator according to any one of claims 1 to 10, wherein in the woven structure, less than 4 tissue points are continuous in an oblique direction.   The dewatering machine according to any one of claims 1 to 11, wherein the woven structure has a complete structure with four pieces of torn.   The first fiber is a pulp having an average fiber length of 0.5 to 5.0 mm, and the second fiber is a synthetic fiber having an average fiber length of 10 to 100 mm. The dehydrator according to claim 1.   14. The dehydrator according to claim 1, wherein the dehydrator has a water spray unit for entangling at least a second fiber at an upper portion of the suction unit with the mesh belt interposed therebetween. Dehydrator. A mesh belt for a sheet dehydrator comprising a first fiber having a first average fiber length and a second fiber having a second average fiber length longer than the first average fiber length,
The dehydrator comprises a transport area for transporting the sheet; and a cleaning area for cleaning the mesh belt; and
(I) a suction unit disposed in a lower portion of the mesh belt in the transport area and having a suction port for sucking moisture contained in the sheet through the mesh belt;
(Ii-1) a surface cleaning unit disposed in the cleaning area for removing first fibers attached to the mesh belt from the surface side of the mesh belt; and
(Ii-2) A back surface cleaning unit for removing the first fibers attached to the mesh belt from the back surface side of the mesh belt disposed in the transport area, the back surface cleaning unit including a back surface cleaning brush,
With
The mesh belt has a surface on the sheet side and a back surface on the opposite side,
The mesh belt has a woven structure formed from a plurality of vertical wires extending in the sheet conveying direction and a plurality of horizontal wires extending in a direction orthogonal to the sheet conveying direction, and in the woven structure The horizontal wire on the surface side returns to the front side after traversing one vertical wire on the back side, and the horizontal wire returned to the front side has two or more vertical wires on the front side. Back to the back side after crossing
The mesh belt as described above.

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