阅读说明：本技术 水刺无纺布 (Spunlace nonwoven fabric ) 是由 木村明宽 出谷耕 泉保真一郎 于 2018-03-16 设计创作，主要内容包括：在具有花纹的水刺无纺布中,使包含多个开孔部的花纹的开孔部与非开孔部的分界清晰,确保花纹的视觉辨识度。水刺无纺布(9)具有：存在花纹(40)的花纹存在区域(9g)；以及花纹存在区域以外的花纹非存在区域(9h)。花纹包含多个开孔部(40a)。在水刺无纺布的灰度图像中,在图像中的表示花纹存在区域的部分中,黑色色阶区域和白色色阶区域分别包含具有像素数的极大值的峰值的色阶,中间色阶区域的中心的色阶的像素数相对于黑色色阶区域的像素数的极大值的比为2以下。(in the spunlace nonwoven fabric with patterns, the boundary between the opening part and the non-opening part of the patterns containing a plurality of opening parts is clear, and the visual identification degree of the patterns is ensured. The spun lace nonwoven fabric (9) comprises: a pattern existing region (9g) in which a pattern (40) exists; and a pattern absent region (9h) other than the pattern present region. The pattern includes a plurality of opening portions (40 a). In a gray scale image of a spunlace nonwoven fabric, in a part of the image which shows a pattern-existing region, a black gradation region and a white gradation region each contain a gradation having a peak of a maximum value of the number of pixels, and the ratio of the number of pixels of the gradation at the center of the intermediate gradation region to the maximum value of the number of pixels of the black gradation region is 2 or less.)

1. A spunlace nonwoven fabric having a pattern in a longitudinal direction, a width direction and a thickness direction, wherein,

The spunlace nonwoven fabric comprises:

A pattern existing region where the pattern exists; and

A pattern non-existing region outside the pattern existing region,

The pattern includes a plurality of perforated portions penetrating the spunlace nonwoven fabric in the thickness direction in a plan view,

In an image obtained by imaging the spun-laced nonwoven fabric from above in the thickness direction,

When a region of a predetermined area of a portion of the image representing the pattern-existing region is divided into a plurality of pixels and the color of each pixel is expressed in a gray scale having a plurality of gradations from black to white, the gray scale having a black gradation region on a black side, a white gradation region on a white side, and an intermediate gradation region between the black gradation region and the white gradation region,

In the portion indicating the pattern presence region,

The black gradation region and the white gradation region respectively contain gradations having peak values of maximum values of the number of pixels,

The ratio of the number of pixels of the gradation at the center of the intermediate gradation region to the maximum value of the number of pixels of the black gradation region is 2 or less.

2. A hydroentangled nonwoven fabric according to claim 1, wherein,

In the portion indicating the pattern presence region,

A ratio of a difference between a value of a central gradation of the intermediate gradation region and a pixel number of the central gradation with respect to a sum of maximum values of pixel numbers of the black gradation region and the white gradation region of a straight line connecting peak values of the black gradation region and the white gradation region to each other is 0.1 or more.

3. A hydroentangled nonwoven fabric according to claim 1 or 2, wherein,

The spunlace nonwoven fabric comprises pulp fibers,

Each of the plurality of opening portions has a contour region that surrounds a through hole of the opening portion by a predetermined width in an in-plane direction parallel to the longitudinal direction and the width direction and extends in the thickness direction,

The pulp fibers in the contour region have a higher fiber density than the pulp fibers in the pattern non-existing region.

4. A hydroentangled nonwoven fabric according to claim 3, wherein,

The spunlace nonwoven fabric comprises a1 st outer layer, a2 nd outer layer and a middle layer which is positioned between the 1 st outer layer and the 2 nd outer layer and contains the pulp fibers.

5. a hydroentangled nonwoven fabric according to claim 4,

the middle layer has a higher fiber density than the fiber density of the 1 st and 2 nd outer layers.

6. A spunlace nonwoven fabric according to any of claims 1-5, wherein,

The intermediate tone scale region contains a tone scale having a minimum value of the number of pixels,

The minimum value is smaller than a maximum value of the number of pixels of the black gradation area and the white gradation area.

7. a spunlace nonwoven fabric according to any of claims 1 to 6, wherein,

The plurality of opening parts includes at least two kinds of opening parts having different shapes from each other,

The shape of each of the at least two types of opening portions is selected from a circle, an ellipse, a polygon, a straight line, a curved line, or a combination of these shapes.

8. A spunlace nonwoven fabric according to any of claims 1 to 7, wherein,

The pattern absent region includes:

A central pattern non-existing region located at a central portion in the width direction of the spun lace nonwoven fabric and extending in the longitudinal direction; and

An end pattern non-existing region located at an end of the spunlace nonwoven fabric in the width direction and extending in the longitudinal direction,

The pattern-existing region includes an end pattern-existing region that is located between the center pattern-absent region and the end pattern-absent region and extends in the longitudinal direction.

Technical Field

The invention relates to a spunlace non-woven fabric.

Background

spunlace nonwoven fabrics are known to be used in various sanitary products such as absorbent articles such as sanitary napkins and disposable diapers, cleaning products such as wet wipes, daily necessities such as paper towels, and medical products such as masks. Such a spunlace nonwoven fabric may have a pattern formed of uneven portions and open-cell portions in order to improve appearance and functionality. For example, patent document 1 discloses a method for producing a spunlace nonwoven fabric having a striped pattern formed by uneven portions and open-cell portions.

In this production method, after the constituent fibers of the fiber web are interlaced (1 st interlacing), a part of the constituent fibers of the fiber web are water-entangled (2 nd interlacing) on a support having a regular pattern (unevenness or opening). A part of the constituent fibers is rearranged to form a plurality of stripes having a regular pattern. That is, a spunlace nonwoven fabric having a striped pattern is formed.

Disclosure of Invention

Problems to be solved by the invention

The pattern of the spunlace nonwoven fabric is mainly represented by the pattern of the concave-convex part and/or the pattern of the open pore part. The pattern of the uneven portion is represented by the difference in height between the concave portion and the convex portion, and the difference in thickness between the uneven portion and the non-uneven portion. However, since the spunlace nonwoven fabric has a small thickness, the difference in height between the concave portions and the convex portions and the difference in thickness between the concave and convex portions and the non-concave and convex portions are small. Therefore, it cannot be said that the pattern of the uneven portion has a high visual recognition. On the other hand, the pattern of the opening portion is represented by the shape of the opening portion, i.e., the color difference between the opening portion and the non-opening portion. Therefore, the pattern of the opening portion can be expected to have a higher visual recognition degree than the pattern of the uneven portion. Therefore, depending on the application, it is desirable to express the pattern of the spunlace nonwoven fabric by the pattern of the open hole portions.

However, the pattern of the opening portion formed by the manufacturing method of patent document 1 has the following problems. When the pattern formed by the open hole portion is formed, the constituent fibers need to be finely moved, but when the pressure of the water flow at the time of the 2 nd interlacing is reduced, the constituent fibers are not so movable and remain in the portion to be the open hole portion. On the other hand, when the pressure of the water flow is increased, the short fibers, which are easy to move, are separated from the area around the opening, and the relatively long fibers are increased around the opening. In this way, the number of irregularities increases around the opening portion, so that the shadows of the irregularities are easily visible, and it is difficult to form a fine pattern. Therefore, in either case, not only the hole portion having sufficient holes but also the hole portion having insufficient holes and the shadow portion in which the irregularities are easily visible are formed around the hole portion. Therefore, the boundary between the opening portion and the non-opening portion may be less visible and may be unclear, and the visual recognition of the pattern may be reduced. There is room for improvement in the boundary of the opening portion of the pattern of the spunlace nonwoven fabric and in the visual recognition of the pattern.

The purpose of the present invention is to provide a spunlace nonwoven fabric having a pattern, wherein the boundary between an open hole portion and a non-open hole portion of the pattern including a plurality of open hole portions can be made clear, and the visual recognition of the pattern can be ensured.

Means for solving the problems

The spunlace nonwoven fabric of the invention is as follows. (1) A spunlace nonwoven fabric having a pattern in a longitudinal direction, a width direction, and a thickness direction, wherein the spunlace nonwoven fabric comprises: a pattern existing region where the pattern exists; and a pattern non-existing region other than the pattern existing region, the pattern including a plurality of perforated portions penetrating the spunlaced nonwoven fabric in the thickness direction in a plan view, wherein in an image obtained by imaging the spunlaced nonwoven fabric from above in the thickness direction, a region of a predetermined area of a portion of the image representing the pattern existing region is divided into a plurality of pixels, and a color of each pixel is expressed by a gray scale having a plurality of gradations from black to white, the gray scale having a black gradation region on a black side, a white gradation region on a white side, and an intermediate gradation region between the black gradation region and the white gradation region, and the black gradation region and the white gradation region each include a gradation having a peak value of a maximum value in the portion representing the pattern existing region, the ratio of the number of pixels of the gradation at the center of the intermediate gradation region to the maximum value of the number of pixels of the black gradation region is 2 or less. The black gradation region is a region of black or gray close to black, the white gradation region is a region of white or gray close to white, and the intermediate gradation region is a region of gray. In addition, although the gray close to black and the gray close to white are also gray, since the gray close to black and the gray close to white are close to black and white, respectively, compared to the gray in the intermediate gradation region, the gray close to black and the gray close to white are described herein as the gray close to black and the gray close to white, respectively, for distinguishing from the gray in the intermediate gradation region.

As described above, the reason for the unclear boundaries between the open hole portions and the reduced visual recognition of the pattern is that there are open hole portions with insufficient openings in the region of the predetermined area including the pattern of the spunlace nonwoven fabric, and there are portions around the open hole portions where the shadows of the irregularities are easily visible. In other words, the cause is a portion which is not visually apparent, that is, a gray portion, such as a portion in which the unevenness is easily visible in a hole portion where holes are not sufficiently formed or a portion in which the shadow of the unevenness is easily visible in the periphery of the hole portion, in addition to a portion in which the gray portion is formed in a nearly black color by the holes and a portion in a nearly white color without the holes. Thus, a hydroentangled nonwoven fabric comprising a pattern formed by apertures may produce more gray portions than a hydroentangled nonwoven fabric not comprising a pattern formed by apertures. In order to relatively reduce the gray portion and to make the boundary of the opening portion clear, the spunlace nonwoven fabric has maximum values (peaks) of the number of pixels in the black gradation region and the white gradation region in the pattern-existing region, and the ratio of the number of pixels of the center gradation of the intermediate gradation region to the maximum value of the number of pixels of the black gradation region is set to 2 or less. That is, in the present spunlace nonwoven fabric, the pattern-existing region is polarized to nearly black gray and nearly white gray, and the ratio of gray formed near the boundary between the open hole portion and the non-open hole portion when the open hole portion is formed to nearly black gray is relatively reduced. Therefore, the user can feel gray close to black and gray close to white more strongly than gray in the present spunlace nonwoven fabric. Therefore, the boundary between the opening part and the non-opening part can be clear, and the patterns can be easily and clearly identified on the whole, namely, the visual identification degree of the patterns is ensured.

The spunlace nonwoven fabric of the present invention may be (2) the spunlace nonwoven fabric according to (1) above, wherein, in the portion indicating the pattern-existing region, a ratio of a difference between a value at a central gradation of the intermediate gradation region and a value of a pixel number of the central gradation with respect to a sum of maximum values of the pixel numbers of the black gradation region and the white gradation region in a straight line connecting peak values of the black gradation region and the white gradation region is 0.1 or more.

In the spunlace nonwoven fabric, in the pattern-existing region, the ratio of the difference between the number of central gradations and the number of central gradations in the intermediate gradation region of a straight line connecting the peak values of the maximum values of the number of pixels in the black gradation region and the white gradation region to the sum of the number of pixels in the maximum values of the black gradation region and the white gradation region is 0.1 or more. That is, in the present spunlace nonwoven fabric, the proportion of gray formed near the boundary between the open cell portion and the non-open cell portion when forming the open cell portion to both gray close to black and gray close to white is relatively reduced in the pattern-existing region. Therefore, the user can feel both a gray color close to black and a gray color close to white more strongly than a gray color in the spun lace nonwoven fabric. Therefore, the boundary between the opening part and the non-opening part can be clearer, and the patterns can be easily and clearly visually identified on the whole, namely, the visual identification degree of the patterns is ensured.

The spunlace nonwoven fabric of the present invention may be (3) the spunlace nonwoven fabric according to (1) or (2) above, the spunlace nonwoven fabric including pulp fibers, the plurality of open hole portions each having a contour region extending in the thickness direction and surrounding a through hole of the open hole portion by a predetermined width in an in-plane direction parallel to the longitudinal direction and the width direction, the pulp fibers in the contour region having a higher fiber density than the pulp fibers in the pattern-absent region.

In the case where the constituent fibers of the spunlace nonwoven fabric include pulp fibers, the pulp fibers have a short fiber length and are fine, and therefore, the adverse effect on the opening portion when the pressure of the water flow of the 2 nd weave is increased is significant. After the production, the spunlaced nonwoven fabric may be wound around a roll or may be put into a package and taken out from a narrow take-out opening. In this case, stress is generated in the spunlace nonwoven fabric, and the shape of the uneven portion and the open hole portion may be deformed by the stress. In the spun lace nonwoven fabric, the pulp fibers in the outline region surrounding the open hole portion have a higher fiber density (exemplified by the number of fibers per unit volume) than the pulp fibers in the pattern-free region. Therefore, in the present spunlace nonwoven fabric, pulp fibers having a short fiber length fill the gaps between constituent fibers having a long fiber length other than the pulp fibers in the profile region, and thus the profile region becomes dense. This makes it possible to make the shape of the opening portion less likely to be deformed, i.e., to maintain the opening shape easily. At the same time, the pulp fibers fill the irregularities in the contour region, and thus the light is easily reflected, so that the degree of whiteness of the contour region can be increased. This makes it possible to make the outline of the opening portion, i.e., the boundary between the non-opening portion and the opening portion clearer, and thus to visually recognize the pattern easily and clearly. That is, the boundary of the opening portion can be made clear, the visual recognition of the pattern can be ensured, and the shape of the opening portion can be maintained.

The spun lace nonwoven fabric of the present invention may be (4) the spun lace nonwoven fabric according to (3) above, which includes a1 st outer layer, a2 nd outer layer, and an intermediate layer located between the 1 st outer layer and the 2 nd outer layer and containing the pulp fiber.

In the spunlace nonwoven fabric, the intermediate layer containing pulp fibers is sandwiched between the 1 st outer layer and the 2 nd outer layer. Therefore, the pulp fibers can be stably held in the contour region of the open hole portion. This makes it possible to maintain the shape of the opening portion stably while making the boundary of the opening portion clear and stably ensuring the visual recognition of the pattern.

The spunlace nonwoven fabric of the present invention may be (5) the spunlace nonwoven fabric according to (4) above, wherein the intermediate layer has a fiber density higher than the fiber densities of the 1 st outer layer and the 2 nd outer layer.

in the present spunlace nonwoven fabric, the intermediate layer comprising pulp fibers has a higher fiber density (exemplified by the number of fibers per unit volume) than the fiber density of the 1 st and 2 nd outer layers. Therefore, the pulp fibers can be more stably held in the contour region of the open hole portion. This makes it possible to maintain the shape of the opening portion more stably while making the boundary of the opening portion clear and ensuring the visual recognition of the pattern more stably.

The spun-laced nonwoven fabric of the present invention may be (6) the spun-laced nonwoven fabric according to any one of (1) to (5), wherein the intermediate tone scale region includes a tone scale having a minimum value of the number of pixels, and the minimum value is smaller than the maximum value of the number of pixels of the black tone scale region and the white tone scale region.

In the spun-laced nonwoven fabric, the gradation (gray) in the intermediate gradation region has a minimum value (downward peak value) of the number of pixels smaller than the maximum value of the number of pixels in the black gradation region and the white gradation region. Therefore, the water-entangled nonwoven fabric can make it more difficult for a user to feel gray, and can make the user feel gray close to black and gray close to white more strongly. Therefore, the boundary between the opening part and the non-opening part can be clear, and the patterns can be easily and clearly identified on the whole, namely, the visual identification degree of the patterns is ensured.

The spunlace nonwoven fabric of the present invention may be (7) the spunlace nonwoven fabric according to any one of (1) to (6), wherein the plurality of open cell parts include at least two types of open cell parts having different shapes from each other, and the shapes of the at least two types of open cell parts are selected from a circle, an ellipse, a polygon, a straight line, a curved line, or a combination thereof.

In the present spunlace nonwoven fabric, the shape of the open pore portion is not limited, and various shapes such as a circle, an ellipse, a polygon, a straight line, a curved line, or a combination of these shapes can be used. Since the above-described shape makes it easy to clearly form the boundary between the opening portion and the non-opening portion, the boundary between the opening portions can be made clearer by appropriately selecting the above-described shape, and the pattern can be visually recognized easily as a whole.

The water-entangled nonwoven fabric of the present invention may be (8) the water-entangled nonwoven fabric according to any one of the above items (1) to (7), wherein the pattern-free region includes: a central pattern non-existing region located at a central portion in the width direction of the spun lace nonwoven fabric and extending in the longitudinal direction; and an end pattern non-existing region located at an end of the spunlace nonwoven fabric in the width direction and extending in the longitudinal direction, wherein the pattern existing region includes an end pattern existing region located between the central pattern non-existing region and the end pattern non-existing region and extending in the longitudinal direction.

In the spunlace nonwoven fabric, the end pattern-existing regions are provided between the central pattern-nonexistent region and the end pattern-nonexistent region. That is, since the pattern is arranged between the regions where the pattern is not present, the pattern can be made more conspicuous, and the visual recognition of the hole portion can be ensured more stably.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide a spunlace nonwoven fabric having a pattern, in which the boundary between an open hole portion and a non-open hole portion of the pattern including a plurality of open hole portions is made clear, and the visual recognition of the pattern is ensured.

Drawings

Fig. 1 is a schematic view showing an example of the structure of a spunlace nonwoven fabric according to an embodiment.

Fig. 2 is a schematic view showing an example of the pattern of the spunlace nonwoven fabric according to the embodiment.

Fig. 3 is a graph showing the relationship between the gradation and the number of pixels of an image obtained by expressing the spun lace nonwoven fabric of the example in terms of gradation.

Fig. 4 is a graph showing the relationship between the gradation and the number of pixels of an image obtained by expressing the spun lace nonwoven fabric of the comparative example in gradation.

Fig. 5 is a schematic diagram showing a configuration example of a manufacturing apparatus used in the method for manufacturing a spunlace nonwoven fabric according to the embodiment.

Fig. 6 is a schematic view showing a part of a configuration example of a manufacturing apparatus used in the method for manufacturing a spunlace nonwoven fabric according to the embodiment.

Fig. 7 is a partially schematic sectional view showing a configuration example of the support body of the 1 st suction drum in the manufacturing apparatus of fig. 6.

Fig. 8 is a schematic diagram showing a configuration example of a water supply device of the manufacturing apparatus of fig. 6.

Fig. 9 is a schematic diagram showing a configuration example of the 1 st spray nozzle of the manufacturing apparatus of fig. 6.

Fig. 10 is a schematic diagram showing a configuration example of a semifinished product of the embodiment.

fig. 11 is a schematic diagram showing a configuration example of the 2 nd spray nozzle of the manufacturing apparatus of fig. 6.

Fig. 12 is a schematic cross-sectional view showing the treatment of the web at the water supply device of fig. 8.

Fig. 13 is a schematic cross-sectional view showing the condition of the web on the support in the process of fig. 12.

Fig. 14 is a partial cross-sectional view schematically showing a configuration example of a semifinished product on a support body after treatment by the first spray nozzle of fig. 9.

Detailed Description

Hereinafter, a spunlace nonwoven fabric of an embodiment will be described. The use of the spunlace nonwoven fabric is not particularly limited, and examples thereof include various sanitary products such as absorbent articles such as sanitary napkins and disposable diapers, cleaning products such as wet wipes, daily necessities such as paper towels, and medical products such as masks.

Fig. 1 is a schematic view showing an example of the structure of a spunlace nonwoven fabric 9 according to an embodiment. Fig. 1 (a) is a partial plan view of the spunlace nonwoven fabric 9 having the pattern 40, and fig. 1 (b) is a partial cross-sectional view of the pattern 40 of fig. 1 (a). The spun lace nonwoven fabric 9 has a longitudinal direction L, a width direction W, and a thickness direction T orthogonal to each other. The "plan view" means that the spunlace nonwoven fabric 9 is viewed from the upper surface side along the thickness direction T. The "in-plane direction" refers to a direction parallel to a plane including the width direction W and the length direction L.

The spunlace nonwoven fabric 9 includes the pattern 40, and further has a pattern existing region 9g in which the pattern 40 exists and a pattern non-existing region 9h other than the pattern existing region 9 g. The pattern 40 includes a plurality of open pore portions 40a penetrating the spunlace nonwoven fabric 9 along the thickness direction T in a plan view. The following describes the details.

the constituent fibers of the spunlace nonwoven fabric 9 are not particularly limited, but in the present embodiment, the fibers include fibers having a short fiber length (hereinafter, referred to as "short fibers") and other fibers. The average fiber length of the short fibers is, for example, 1 to 30mm, preferably 2 to 10mm, and more preferably 2 to 5mm from the viewpoint of absorption and retention of liquid. On the other hand, the average fiber length of the fibers other than the short fibers is longer than the average fiber length of the short fibers, and is, for example, 30 to 80mm, preferably 30 to 60mm, from the viewpoint of maintaining the structure. The fineness of the fibers other than the short fibers is, for example, 1 to 6 dtex.

The short fibers are not particularly limited, but examples thereof include synthetic fibers and natural fibers, and in the present embodiment, pulp fibers of natural fibers can be used from the viewpoint of liquid absorbency and the like. The pulp fiber is not particularly limited, but can be exemplified by wood pulp and non-wood pulp. Examples of the wood pulp include softwood pulp and hardwood pulp. Examples of the non-wood pulp include straw pulp, bagasse pulp, reed pulp, hemp pulp, mulberry pulp, bamboo pulp, hemp pulp, and cotton pulp.

On the other hand, fibers other than the short fibers (pulp fibers in the present embodiment) are not particularly limited, but examples thereof include synthetic fibers (exemplified by thermoplastic resin fibers), natural fibers, regenerated fibers, and a combination of at least two of the foregoing fibers. Examples of the material of the thermoplastic resin fiber include polyolefin, polyester, polyamide, and acrylic. Examples of the polyolefin include Polyethylene (PE), polypropylene (PP), and a copolymer mainly composed of Polyethylene (PE) and polypropylene (PP). Examples of the polyester include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and a copolymer mainly composed of polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). Examples of the polyamide include nylon 6 and nylon 66. As the acrylic acid, Polyacrylonitrile (PAN) can be mentioned. When the thermoplastic resin fibers are used, hydrophilization treatment may be performed, and examples of the hydrophilization treatment include treatment with a surfactant, a hydrophilic agent, and the like. Examples of the natural fibers include wool and cotton. Examples of the regenerated fibers include rayon and acetate fibers. Further, a part or the whole of the constituent fibers may be a core-sheath fiber, a side-by-side fiber, a composite fiber such as an island-in-sea fiber, a hollow fiber, or a three-dimensional crimped fiber having latent crimp or significant crimp.

The proportion of pulp fibers in the spunlace nonwoven fabric 9 is 20 mass% or more from the viewpoint of liquid absorbency, and the proportion of pulp fibers in the spunlace nonwoven fabric 9 is less than 70 mass% from the viewpoint of maintaining the structure. The thickness of the spun lace nonwoven fabric 9 is, for example, 0.2 to 5 mm. The weight per unit area is, for example, 10 to 200g/m². The fiber density may be, for example, 0.05 to 0.3g/cm³. In the present embodiment, the above-described value is a value measured in the pattern absent region 9 h.

The layer structure of the spunlace nonwoven fabric 9 may be a single layer or a plurality of layers, and is not limited to this, but in the present embodiment, a three-layer structure (not shown) is adopted. I.e. spunlace nonwoven9 has a three-layer construction comprising a1 st outer layer, a2 nd outer layer, and an intermediate layer located between the 1 st and 2 nd outer layers. The constituent fibers of the 1 st and 2 nd outer layers are not particularly limited, but from the viewpoint of mainly maintaining the structure, for example, fibers other than the pulp fibers described above can be used. The fiber density of the constituent fibers of the 1 st and 2 nd outer layers is, for example, 0.02 to 0.06g/cm³. The structures of the 1 st and 2 nd outer layers, for example, the kind of fibers, the mixing ratio, and the layer structure may be the same or at least one of them may be different. On the other hand, the constituent fibers of the intermediate layer are not particularly limited, but the pulp fibers and fibers other than pulp fibers described above can be used in combination mainly from the viewpoint of liquid absorbency and liquid retention. The pulp fiber content in the intermediate layer is 20 mass% or more and 100 mass% or less from the viewpoint of liquid absorbency and retention. In the present embodiment, the middle layer has a higher fiber density than the fiber density of the 1 st and 2 nd outer layers. The fiber density of the constituent fibers of the intermediate layer is, for example, 0.03 to 0.25g/cm³。

The pattern 40 of the spunlace nonwoven fabric is mainly formed by a plurality of uneven portions and/or a plurality of open-cell portions, and in the present embodiment, is mainly formed by a plurality of open-cell portions 40 a. The perforated portion 40a is a through hole penetrating the spunlace nonwoven fabric 9 along the thickness direction T. The plurality of opening portions 40a include a plurality of types of opening portions having different shapes from each other. The shape of each of the plurality of types of opening portions includes a circle, an ellipse, a polygon, a straight line, a curved line, or a combination of these shapes. Wherein, the straight line (line segment) and the curve have certain thickness. In the present embodiment, the pattern 40 is a transparent pattern such as a lace formed by combining various complicated shapes as shown in fig. 1 (a). However, the pattern 40 is not limited to this example. The size of one opening 40a may be 0.4 to 20mm in terms of internal dimension and 0.12 to 100mm in terms of area²The distance between adjacent opening parts 40a is 0.2 to 10 mm.

The opening portion 40a has a contour region 41 surrounding the through hole with a predetermined width in the in-plane direction and extending along the thickness direction T. In other words, the outline region 41 is a tubular region extending along the side wall 40aH surrounding the opening portion 40a and having a predetermined width in the in-plane direction. Here, the predetermined width may be D/2, which is half the thickness D of the spun lace nonwoven fabric 9. The outline of the opening portion 40a at an arbitrary thickness in the thickness direction T is a line connecting the ends of the fibers closest to the opening side in the in-plane direction (including the side surfaces of the fibers) so as to surround the opening. The side wall 40aH is a circumferential surface of an opening formed by connecting contours at each thickness portion in the thickness direction T along the thickness direction T. When the distance between the hole portions 40a adjacent to each other is short and the predetermined widths of the two overlap each other, the predetermined width is half the distance between the two. However, the predetermined width is not limited to the above example, and may be another value, for example, D/n (n is a value larger than 2), or 1/m (m is a value of 2 or more) of the internal dimension D in the in-plane direction of the opening portion. The pulp fibers in the outline region 41 have a fiber density (number per unit volume) higher than that of the pulp fibers in the pattern non-existing region 9h, in other words, higher than that of the pulp fibers in the regions other than the outline region 41. In the case where the spunlace nonwoven fabric 9 has a multilayer structure, for example, a three-layer structure, the fiber density is evaluated by averaging the three layers in the thickness direction T.

The pattern-existing region 9g is a region of the spunlace nonwoven fabric 9, which is mostly occupied by the pattern 40 in a plan view, that is, a region including the pattern 40, and is, for example, a region extending outward from the outline of the pattern 40 to a certain extent. On the other hand, the pattern absent region 9h is a region of the spunlace nonwoven fabric 9 excluding the pattern present region 9g in a plan view. In the present embodiment, the pattern existing region 9g and the pattern non-existing region 9h are a region that is water-flow-interlaced and a region that is not water-flow-interlaced in the pre-interlacing and transfer step, which will be described later. In the present embodiment, the pattern non-existing region 9h includes a central pattern non-existing region 9h-a located at the central portion in the width direction W of the spunlace nonwoven fabric 9 and extending in the longitudinal direction L and end pattern non-existing regions 9h-b located at the end portions in the width direction W of the spunlace nonwoven fabric 9 and extending in the longitudinal direction L, and the end pattern non-existing regions 9h-b may be disposed at both end portions in the width direction W of the spunlace nonwoven fabric 9. The pattern existing region 9g includes an end pattern existing region 9g-a located between the center pattern absent region 9h-a and the end pattern absent region 9h-b and extending in the longitudinal direction L.

In the present embodiment, a transparent pattern such as a lace formed by combining various complicated shapes is used as the pattern 40, but the pattern is not limited to this example. Fig. 2 is a schematic view showing another example of the pattern 40 of the spunlace nonwoven fabric according to the embodiment. This pattern 40y can be used instead of the pattern 40 of the pattern-existing region 9g-a at the end of the spunlace nonwoven fabric 9 shown in fig. 1 (a). The pattern is a transparent pattern composed of small opening portions of various shapes.

next, the definition of the boundary between the opening portion 40a and the non-opening portion of the pattern 40 will be described.

Fig. 3 and 4 are graphs showing the relationship between the gradation and the number of pixels of images obtained by expressing the below-described spunlace nonwoven fabric 9 of example 1 and comparative example 1 in gradation, respectively. Fig. 3 (a) is a schematic view showing a region S of a predetermined area selected from a portion showing the pattern existing region 9g in an image obtained by imaging a spunlace nonwoven fabric. Fig. 3 (b) and 4 are graphs each showing the relationship between the number of pixels (vertical axis) and the number of gradations (horizontal axis) when a region S of a predetermined area in an image obtained by imaging the spunlace nonwoven fabric of example 1 and comparative example 1 from above in the thickness direction T under the same conditions is divided into a plurality of pixels and the color of each pixel is expressed by a gradation having a plurality of gradations from black to white. The peak of the maximum value is set to 1 and the number of pixels is normalized. The gray level is set to a black gradation region A having a black side_BWhite gradation region A on the white side_WAnd a black tone region A_BAnd a white gradation region A_WIntermediate tone scale region A in between_MThereby, the black gradation region A_BIs a black or nearly black gray region, a white gradation region A_WIs a white or near-white gray (containing translucency) region, in the middleColor gradation region A_MAre areas of grey. In the present embodiment, all the gradations are roughly divided into three, and the gradation of 1/3 on the black side is defined as a black gradation area a_BThe gradation of 1/3 on the white side is defined as a white gradation region A_WThe intermediate 1/3 gradation is defined as an intermediate gradation region A_M. Specifically, in the present embodiment, the gradation is 256 gradations of 0 to 255, and the gradations of 0 to 84/85 to 170/171 to 255 are each a black/intermediate/white gradation region. The specific data acquisition method of fig. 3 and 4 will be described later.

In a region S1 of fig. 3 (a) showing a predetermined area of a portion of the pattern existing region 9g of example 1, as shown in fig. 3 (b), a black gradation region a_BAnd a white gradation region A_WEach having a maximum value P having a pixel number_BM1、P_WM1Color level G of peak value of_BM1、G_WM1. Here, the black gradation region a can be said to be_BAnd a white gradation region A_WEach having a peak value of a maximum value of the number of clear pixels. And, the color gradation G of the center of the intermediate color gradation region_MM1Number of pixels P_MM1Relative to black tone scale region A_BMaximum value P of the number of pixels of_BM1The ratio RG1 is 2.0 or less. Specifically, (G) in FIG. 3 (b)_BM1、P_BM1)、(G_WM1、P_WM1)、(G_MM1、P_MM1) Respectively (77, 0.43), (191, 1.00), (127, 0.57). And, RG1 ═ P_MM1/P_BM1＝0.57/0.43＝1.3≤2.0。

On the other hand, in a region S2 (S1) of a predetermined area of the portion of the pattern existing region in comparative example 1 shown in fig. 4 (a), as shown in fig. 4 (b), a white gradation region a is formed_Wincluding a maximum value P having a number of pixels_WM2Color level G of peak value of_WM2. However, the black gradation region A cannot be said_Ba tone scale including a peak having a maximum value of the number of pixels. Even though it can be said that the black gradation area A is unclear_Bincluding a maximum value P having a number of pixels_BM2color level G of peak value of_BM2Central tone scale G of intermediate tone scale region_MM2Number of pixels P_MM2Relative to black tone scale region A_BMaximum value P of the number of pixels of_BM2The ratio RG1 of (a) is also greater than 2.0 but not 2 or less. Specifically, (G) in FIG. 4 (b)_BM2、P_BM2)、(G_WM2、P_WM2)、(G_MM2、P_MM2) Respectively (81, 0.20), (191, 1.00), (127, 0.42). And, RG1 ═ P_MM2/P_BM2＝0.42/0.20＝2.1＞2.0。

as described above, the spunlace nonwoven fabric having the pattern includes not only a gray portion close to black formed by openings and a gray portion close to white formed by non-openings, but also an inconspicuous portion formed by an opening portion having insufficient openings or a portion in which a shadow of unevenness is easily seen in the periphery of the opening portion, that is, a gray portion. That is, a spunlace nonwoven fabric including a pattern formed of apertures may generate a larger amount of gray portions than a spunlace nonwoven fabric not including a pattern formed of apertures. Accordingly, in the spun lace nonwoven fabric 9, in order to relatively reduce the gray portion, the pattern-existing region 9g includes the black gradation region a_BAnd a white gradation region A_WEach color gradation has a maximum value P of the number of pixels_BM1、P_WM1(Peak), intermediate gradation region A_MPixel number P of the central tone step_MM1Relative to black tone scale region A_BMaximum value P of the number of pixels of_BM1The ratio RG1 of (a) is 2 or less. That is, in the spunlace nonwoven fabric 9, the pattern-existing regions 9g are polarized to gray close to black and gray close to white, and the ratio of the gray portion formed in the vicinity of the boundary between the opening portion 40a and the non-opening portion to the gray portion close to black is relatively reduced. Therefore, in the spun lace nonwoven fabric 9, gray close to black and gray close to white can be more strongly felt by the user than gray. This makes it possible to clearly demarcate the opening portion 40a from the non-opening portion, and to visually recognize the pattern as a whole, that is, to ensure the visual recognition of the pattern.

In a preferred embodiment of the present invention, in the area S1 in fig. 3 (a), as shown in fig. 3 (b)Black gradation area A_BAnd a white gradation region A_Wcentral gradation G of the intermediate gradation region of the straight line E1 connecting the peak values of_MM1Value P of_MM1' and central color level G_MM1Number of pixels P_MM1The difference Δ 1 with respect to the black gradation area A_BAnd a white gradation region A_WMaximum value sum (P) of the number of pixels of (1)_BM1+P_WM1) The ratio RG2 is 0.10 or more. Specifically, (G) in FIG. 3 (b)_BM1、P_BM1)、(G_WM1、P_WM1)、(G_MM1、P_MM1)、(G_MM1、P_MM1') are (77, 0.43), (191, 1.00), (127, 0.57), (127, 0.76), respectively. RG2 ═ Δ 1/(P)_BM1+P_WM1)＝(0.76－0.57)/(0.43+1.00)＝0.13≥0.10。

On the other hand, in the region S2(═ S1) in fig. 4 (a), as shown in fig. 4 (b), the black gradation region a is formed_BAnd a white gradation region A_WCentral gradation G of the intermediate gradation region of the straight line E2 connecting the peak values of_MM2Value P of_MM2' and central color level G_MM2Number of pixels P_MM2The difference Δ 2 with respect to the black gradation area A_BAnd a white gradation region A_WMaximum value sum (P) of the number of pixels of (1)_BM2+P_WM2) Is less than 0.10 but not more than 0.10. Specifically, (G) in FIG. 4 (b)_BM2、P_BM2)、(G_WM2、P_WM2)、(G_MM2、P_MM2)、(G_MM2、P_MM2') are (81, 0.20), (191, 1.00), (127, 0.42), (127, 0.53), respectively. And RG2 ═ Δ 2/(P)_BM2+P_WM2)＝(0.53－0.42)/(0.20+1.00)＝0.092＜0.10。

In this way, in the spunlaced nonwoven fabric 9, the black gradation region a is formed in the pattern-existing region 9g_BAnd a white gradation region A_WMaximum value P of the number of pixels of_BM1、P_WM1The intermediate tone scale region A of the straight line E1 connecting the peak values of_MValue P at the central color level of_MM1' number of pixels P of central gradation_MM1Difference Δ 1 with respect to black levelRegion A_BAnd a white gradation region A_Wthe sum (P) of the number of pixels of the maximum value of_BM1+P_WM1) The ratio of (A) to (B) is 0.10 or more. That is, in the spun lace nonwoven fabric 9, in the pattern-existing region 9g, the ratio of the gray portion formed in the vicinity of the boundary between the open pore portion 40a and the non-open pore portion to the two portions of the gray portion close to black and the gray portion close to white is relatively reduced. Therefore, in the spun lace nonwoven fabric 9, both of the gray color close to black and the gray color close to white can be more strongly perceived by the user than the gray color. This makes it possible to make the boundary between the opening portion 40a and the non-opening portion clearer, and to make it easier to visually recognize the pattern as a whole, that is, to ensure the visual recognition of the pattern.

In a preferred embodiment of the present invention, the intermediate tone scale region a is, as shown in fig. 3 (b)_MContaining a minimum value P having the number of pixels_MMIN1(here, downward peak) gradation G_MMIN1. Minimum value P_MMIN1Darker gradation area A_BAnd a white gradation region A_WMaximum value P of the number of pixels of_BM1、P_WM1Is small. Specifically, (G) in FIG. 3 (b)_BM1、P_BM1)、(G_WM1、P_WM1)、(G_MMIN1、P_MMIN1) Respectively (77, 0.43), (191, 1.00), (94, 0.42). And, P_BM1、P_WM1＝0.43、1.00＞0.42＝P_MMIN1。

On the other hand, as shown in fig. 4 (b), the intermediate tone scale region a cannot be said_MContaining a minimum value P having the number of pixels_MMIN2(here, downward peak) gradation G_MMIN2. In other words, there is no more black gradation region A_BAnd a white gradation region A_WMaximum value P of the number of pixels of_BM1、P_WM1Small minimum value P_MMIN2。

Thus, in the spun lace nonwoven fabric 9, the intermediate gradation region A_MHas a color gradation (gray) of a region A having a color gradation higher than that of black_Band a white gradation region A_WMaximum value P of_BM1、P_WM1Minimum value P of small number of pixels_MMIN1(in the direction ofThe lower peak). Therefore, the spun lace nonwoven fabric 9 can make it more difficult for the user to feel gray, and can make the user feel gray close to black and gray close to white more strongly. This makes it possible to clearly demarcate the opening portion 40a from the non-opening portion, and to visually recognize the pattern as a whole, that is, to ensure the visual recognition of the pattern.

Further, in the case where the constituent fibers of the spunlace nonwoven fabric 9 include pulp fibers, the pulp fibers are short in length and fine and light in fiber, and therefore, when the pressure of the water flow in the water flow interlacing is increased, the pulp fibers easily move from the periphery of the open hole portion to other portions, and therefore the boundary of the open hole portion is easily unclear. After the production, the spunlace nonwoven fabric 9 may be wound around a roll or may be taken out from a narrow take-out opening after being packaged in a package, and the shape of the perforated portion 40a may be deformed by stress generated at that time. In a preferred embodiment of the present embodiment, the spunlace nonwoven fabric 9 has a feature in that the pulp fibers in the outline regions 41 surrounding the open hole portions 40a have a higher fiber density (number per unit volume) than the pulp fibers in the pattern non-existing regions 9 h. Therefore, in the spun lace nonwoven fabric 9, the pulp fibers having a short fiber length fill the gaps between the constituent fibers having a long fiber length other than the pulp fibers in the profile region 41, and therefore the profile region 41 becomes dense. This makes it possible to make the shape of the opening portion 40a less likely to be deformed, that is, to make it easier to maintain the opening shape. At the same time, in the outline region 41, the pulp fibers fill the unevenness, whereby light is easily reflected, and therefore the degree of white color of the outline region 41 can be increased. This makes it possible to make the outline of the opening portion 40a, i.e., the boundary between the non-opening portion and the opening portion 40a clearer, and thus to make it easier to visually recognize the pattern clearly. That is, the boundaries of the opening portion 40a are made clear, the visual recognition of the pattern 40 is ensured, and the shape of the opening portion 40a is maintained.

In a preferred embodiment of the present embodiment, the shape of the perforated portion 40a in the spunlace nonwoven fabric 9 can be a circle, an ellipse, a polygon, a straight line, a curved line, or a combination of these shapes. Since the boundary between the opening portion 40a and the non-opening portion is easily formed clearly by the above-described shape, the boundary between the opening portions 40a can be made clearer by appropriately selecting the above-described shape, and the pattern 40 can be easily visually recognized as a whole.

In a preferred embodiment of the present embodiment, the spunlace nonwoven fabric 9 has end pattern-existing regions 9g-a between the center pattern-nonexistent region 9h-a and the end pattern-nonexistent regions 9 h-b. That is, since the pattern is disposed between the two regions where the pattern 40 is not present, the pattern 40 can be made more conspicuous. This makes it possible to make the boundaries of the opening hole portions 40a clearer and to ensure the visual recognition of the pattern 40 more stably.

In a preferred embodiment of the present embodiment, the intermediate layer containing pulp fibers is sandwiched between the 1 st and 2 nd outer layers in the spun lace nonwoven fabric 9. Therefore, the pulp fibers can be stably held in the contour region 41 of the open hole portion 40 a. This makes it possible to maintain the shape of the opening portion 40a stably while making the boundary of the opening portion 40a clear and stably securing the visual recognition of the pattern 40.

In a preferred embodiment of the present embodiment, the intermediate layer containing pulp fibers in the spun lace nonwoven fabric 9 has a fiber density (number per unit volume) higher than the fiber densities (numbers per unit volume) of the 1 st and 2 nd outer layers. Therefore, the pulp fibers can be more stably held in the contour region 41 of the open hole portion 40 a. This makes it possible to maintain the shape of the opening portion 40a more stably while making the boundary of the opening portion 40a clear and ensuring the visual recognition of the pattern 40 more stably.

Next, a method for producing the spunlace nonwoven fabric 9 having the pattern 40 according to the present embodiment will be described.

The method for producing the spunlace nonwoven fabric 9 having the pattern 40 includes a web forming step of producing the web 7, a moistening and dewatering step of moistening and dewatering the web 7, a pre-interlacing step of interlacing the web 7 and simultaneously transferring the uneven pattern to form the semi-finished product 8 having the pattern 40, a transfer step, a post-interlacing step of further interlacing the semi-finished product 8 to form the spunlace nonwoven fabric 9 having the pattern 40, and a post-processing step of the spunlace nonwoven fabric 9.

Fig. 5 is a schematic diagram showing a configuration example of a manufacturing apparatus used in the method for manufacturing a spunlace nonwoven fabric according to the embodiment. The manufacturing apparatus 1 includes a web forming apparatus 110, a nonwoven fabric forming apparatus 120, and a nonwoven fabric post-treatment apparatus 130. In the manufacturing apparatus 1, the conveyance direction of the web 7, the semi-finished product 8, and the spun lace nonwoven fabric 9 is MD, and the direction perpendicular to the conveyance direction MD, that is, the width direction of the web 7 and the like is the cross direction CD. The conveyance direction MD is the same as the longitudinal direction L of the spunlace nonwoven fabric 9, and the transverse direction CD is the same as the width direction W of the spunlace nonwoven fabric 9.

First, a web forming process is performed using the web forming device 110.

The web forming apparatus 110 is an apparatus for forming a web 7 from fibers and includes a1 st carding machine 21, an air spinner 22, a2 nd carding machine 23, and a web conveying apparatus 11. The 1 st carding machine 21 feeds the fibers constituting the 1 st fiber laminate 7-1 from a feeder to form the 1 st fiber laminate 7-1. The 1 st fiber laminate 7-1 finally becomes the 1 st outer layer. The air spinner 22 feeds the fibers constituting the 2 nd stacked fiber body 7-2 from the feeder to form the 2 nd stacked fiber body 7-2 on the 1 st stacked fiber body 7-1. The 2 nd fiber laminated body 7-2 finally becomes an intermediate layer. The 2 nd carding machine 23 feeds the fibers constituting the 3 rd fiber laminate 7-3 from the feeder to form the 3 rd fiber laminate 7-3 on the 2 nd fiber laminate 7-2. The 3 rd fiber laminated body 7-3 finally becomes the 2 nd outer layer. Then, the 1 st to 3 rd fiber laminated bodies 7-1 to 7-3 are laminated to form a web 7. The web 7 is transferred from the web conveying belt 11a of the web conveying device 11 to the nonwoven fabric forming device 120. The web 7 is formed by stacking a plurality of fiber laminates, and is not subjected to a weaving process for weaving fibers with each other. The layered fiber bodies constituting the web 7 can be arbitrarily selected according to the application of the nonwoven fabric to be produced, and the like.

The fibers of the web 7 can be arbitrarily selected according to the use of the nonwoven fabric to be produced, and the like. The fiber density of the web 7 is, for example, 2X 10^－3～4×10^－3g/cm³Left and right. The weight per unit area of the web 7 is, for example, 20 to 70g/m²Left and right. The thickness of the web 7 is, for example, about 7 to 20 mm.

Next, the nonwoven fabric forming apparatus 120 performs a moistening step, a dewatering step, a pre-interlacing step, a transfer step, and a post-interlacing step. Fig. 6 is a schematic view showing a nonwoven fabric forming apparatus 120 in the configuration example of the manufacturing apparatus of fig. 5. The nonwoven fabric forming apparatus 120 includes an upstream side conveying device 13, a1 st suction drum 5, a water supply device 2, a1 st spray nozzle 3, a2 nd suction drum 6, a2 nd spray nozzle 4, a downstream side conveying device 14, and a dewatering machine 25.

First, the upstream side transport device 13, the 1 st suction drum 5, and the water supply device 2 perform a wetting and dehydrating process. The upstream side transport device 13 transports the web 7 formed by the web forming device 110 by the upstream side transport belt 13a, and switches the transport direction upward by the direction switching roller 12 to transport the web to the 1 st suction drum 5. At this time, the web 7 is conveyed so that the 1 st surface 7a of the web 7 faces the outside of the upstream conveyor 13 and the 2 nd surface 7b opposite to the 1 st surface 7a comes into contact with the upstream conveyor belt 13 a.

Next, the 1 st suction roller 5 includes a support body having an uneven pattern on the surface thereof on the outer circumferential surface 5 a. The 1 st suction drum 5 sucks the web 7 conveyed by the upstream side conveyor 13 via the support while rotating the support about the axis a1, and conveys the web to the 2 nd suction drum 6 while holding the web on the outer peripheral surface 5 a. At this time, the web 7 is conveyed along the surface of the support body so that the 1 st surface 7a faces the outside of the 1 st suction roller 5 and the 2 nd surface 7b faces the inside of the 1 st suction roller 5 to contact the outer peripheral surface 5 a.

Fig. 7 is a partial cross-sectional view schematically showing a structural example of the support 54. As shown in fig. 7, the support 54 includes a base 56 and an uneven pattern 55 formed on the surface of the base 56. The base material 56 is disposed on the outer peripheral surface 5a, and has a plurality of mesh-like holes through which liquid and gas can pass. The uneven pattern 55 is a concave portion or a convex portion having a pattern shape, and in the present embodiment, is a convex portion having a predetermined pattern shape. The height h of the projections can be arbitrarily selected according to the use of the nonwoven fabric to be produced, the shape of the pattern, and the like, and is, for example, 0.1 to 10 mm.

Next, referring to fig. 6, the water supply device 2 sprays water from the 1 st surface 7a side to the web 7 held on the outer peripheral surface 5a of the 1 st suction drum 5, fills the space between the fibers of the web 7 with water, and wets the web 7. The 1 st suction roll 5 sucks water from the 2 nd surface 7b side to dewater the wet web 7 at a position substantially opposite to the water supply device 2. That is, the water filled in the space between the fibers of the web 7 is sucked by the 1 st suction roll 5 and substantially removed.

fig. 8 is a diagram schematically showing a configuration example of the water supply device 2 of the manufacturing apparatus 1. The water supply device 2 includes, for example, an opening 2a linearly arranged in a direction parallel to the transverse direction CD, and discharges low-pressure water supplied from a fluid source, not shown, directly from the opening 2a as water 30 without pressurizing the water. The water 30 is free-falling directly to be sprinkled on the web 7. In addition, the water supply device 2 is intended not to interlace the fibers of the web 7 with each other with water but to contain water in the web 7, and therefore the water supply device 2 does not spray water at high pressure but sprinkles water on the web 7. Thus, water may be allowed to freely fall from a position near the web 7 to the web 7 as shown in fig. 8, or water sprayed by a sprayer may be applied to the web 7.

Here, the pressure of the water sprayed by the water supply device 2 (the water pressure when the water is discharged from the opening of the water supply device 2) is determined according to the thickness of the web 7 and the type of structural fibers, but the web 7 may be wet without substantially interlacing the web 7, and therefore, it may be greater than 0.1MPa (atmospheric pressure) and 0.8MPa or less, and preferably greater than 0.1MPa (atmospheric pressure) and 0.5 MPa. The amount of water to be supplied to the web 7 is determined depending on the thickness of the web 7 and the type of structural fibers, but the amount of water to be supplied to the web 7 may be 100 to 150L/min. In this way, the pressure of the water sprayed from the water supply device 2 is kept low, and it is possible to prevent the fibers from scattering or scattering from the web 7, which is not subjected to the treatment of interlacing the fibers, due to the water from the water supply device 2.

Fig. 12 is a cross-sectional view schematically showing a state where the web 7 is moistened by the water supply device 2 and the web 7 is dewatered by the 1 st suction roll 5. First, in fig. 12 (a), the web 7 is disposed on the outer circumferential surface 5a of the 1 st suction roll 5. At this time, the web 7 contains more spaces between the fibers and is in a bulky state, i.e., a thick state. Next, in fig. 12 (b), water is sprayed onto the web 7 by the water supply device 2. At this time, the spaces between the fibers of the web 7 are filled with water, but the fluffy state (thick state) is not changed. Then, in fig. 12 (c), the web 7 is dewatered by sucking water contained in the web 7 by the 1 st suction roll 5. At this time, since the water contained in the web 7 is chemically bonded (hydrogen-bonded) to the fibers of the web 7, the fibers of the web 7 are pulled toward the 1 st suction roll 5 by the water sucked into the 1 st suction roll 5. Alternatively, the fibers of the web 7 are physically pushed toward the 1 st suction roll 5 by the water sucked into the 1 st suction roll 5. As a result, the fibers of the web 7 are attracted toward the 1 st suction roller 5 side with the movement of water, the space between the fibers of the web 7 is drastically reduced, the volume of the web 7 is reduced as a whole (the thickness is reduced), and the fiber density of the web 7 is increased.

The fibre density of the web 7 immediately after moistening with the water supply means 2 and dewatering with the 1 st suction cylinder 5 is 4 x 10^－2～8×10^－2g/cm³Left and right. If the fiber density is too high, it becomes difficult to move the fibers of the web 7 by the water flow of the 1 st jet nozzle 3 in the subsequent step. If the fiber density is too low, there is an adverse effect that fibers of the web 7 are scattered by the impact of the water flow from the 1 st jet nozzle 3, and the texture is scattered. The fiber density is higher than the fiber density before treatment with the water supply device 2. The weight per unit area of the fiber web 7 is 20 to 70g/m²The thickness of the fiber web 7 is about 1 to 5 mm.

In this way, water is supplied from the water supply device 2 to the web 7, and the web 7 is dewatered by the 1 st suction roll 5, whereby the web 7 can be thinned, and the fiber density of the web 7 can be easily increased to the predetermined range. Further, the web 7 is dewatered, and the water contained in the web 7 becomes very small, so that the energy of the water ejected from the 1 st ejection nozzle 3 can be efficiently transmitted to the web 7 in the subsequent process. When the fiber density of the web 7 is set to the above-mentioned predetermined range, the fibers are in close contact with each other, and the bonding between the fibers becomes stronger than immediately after the formation of the web 7 (but the bonding becomes weaker than in the case of interlacing the web 7). Further, the fibers on the surface of the web 7 are hardly raised and are laid down along the surface. Therefore, when the uneven pattern is transferred to the web 7 while the fibers of the web 7 are entangled with each other in the post-process, it is possible to suppress a situation in which the fibers of the web 7 are scattered by the impact of the water jet ejected from the first ejection nozzle 3, the fiber density of the web 7 becomes uneven, and the texture of the web 7 is scattered.

Fig. 13 is a cross-sectional view schematically showing the state of the web 7 on the concave-convex pattern 55 in the step of wetting and dewatering in fig. 12. When the web 7 is placed on the uneven pattern 55 of the support 54, the temporary pattern 42 is formed on the web 7 by wetting with the water supply device 2, sucking and dewatering the web by the 1 st suction roll 5, and deforming the web 7 in accordance with the shape of the uneven pattern 55. In the temporary pattern 42, a gap SG or the like exists between the concave-convex pattern 55 and the web 7, and it cannot be said that the concave-convex pattern 55 is transferred to the web 7. However, since the temporary pattern 42 and the uneven pattern 55 have shapes that substantially fit each other, the web 7 can be fixed to the uneven pattern 55. Thus, when the water jet is injected to the web 7 by the first injection nozzle 3 in the subsequent step, the web 7 can be prevented from moving due to the jet flow.

Next, the 1 st suction cylinder 5 and the 1 st spray nozzle 3 perform a pre-interlacing and transfer process. Referring to fig. 6, the 1 st spray nozzle 3 sprays water (1 st water stream) from the 1 st surface 7a side to the web 7 held on the outer peripheral surface 5a of the 1 st suction drum 5. That is, the 1 st jet nozzle 3 presses the web 7 against the concave-convex pattern 55 of the support 54 while interlacing the fibers of the web 7, and transfers the concave-convex pattern 55 to the web 7. Thereby, the semi-finished product 8 having the pattern (the plurality of opening portions) 40 is formed. In the present embodiment, two 1 st spray nozzles 3-1 and 3-2 are provided as the 1 st spray nozzle 3 in this order from the upstream side in the conveyance direction of the web 7, but the number thereof is not particularly limited. The 1 st injection nozzles 3-1, 3-2 inject water from a row of a plurality of nozzle holes arranged linearly along the transverse direction CD and at a constant pitch. The 1 st suction roller 5 sucks water from the 2 nd surface 7b side to the web 7 being interlaced and transferred at a position substantially opposed to the 1 st spray nozzles 3-1 to 3-2, and reliably sucks and stably holds the web 7. Pattern-existing regions in which a pattern exists and pattern-nonexistent regions in which a pattern does not exist are formed in the semi-finished product 8.

The injection pressure of the water flow of the 1 st injection nozzles 3-1 to 3-2 is increased as it goes toward the conveyance direction MD of the web 7. Specifically, on the support 54 having the uneven pattern 55, in order to start the transfer of the uneven pattern 55 to the web 7 at the same time as the interlacing of the web 7 is started, the jetting pressure P11 of the water stream of the 1 st jetting nozzle 3-1 (the water pressure when discharged from the nozzle hole of the 1 st jetting nozzle 3-1) is higher than the water pressure of the water supply device 2, and is preferably 1.0MPa or more and P11 or less and 6.0MPa or more. On the support 54 having the uneven pattern 55, in order to perform the interlacing of the web 7 and the transfer of the uneven pattern 55 to the web 7, the jetting pressure P12 of the water stream of the 1 st jetting nozzle 3-2 (the water pressure when discharged from the nozzle hole of the 1 st jetting nozzle 3-2) is preferably 3.0MPa or less and P12 or less and 7.0 MPa. Wherein P11 is less than P12.

Fig. 9 is a diagram schematically showing a configuration example of the 1 st spray nozzle 3 of the manufacturing apparatus 1. In fig. 9, only the 1 st spray nozzle 3-1 located on the most upstream side is shown, and the 1 st spray nozzle 3-2 is omitted. The 1 st spray nozzles 3-1 and 3-2 spray water at high pressure from the 1 st surface 7a side of the web 7 to the web 7 held on the outer peripheral surface 5a of the 1 st suction drum 5, thereby forming a pattern 40 in which the uneven pattern 55 is transferred on the web 7 and interlacing the fibers of the web 7 with each other. The web 7 is thus formed into a semi-finished product 8 having a pattern 40.

Fig. 10 is a diagram schematically showing a configuration example of the semi-finished product 8 having the pattern 40. The semi-finished product 8 has a pattern-existing region 8g and a pattern-nonexistent region 8h, the pattern-existing region 8g having a pattern 40 extending in the conveyance direction MD, and the pattern-nonexistent region 8h having no pattern 40 extending in the conveyance direction MD. In the example of the figure, pattern absent areas 8h are formed in the central portion and both end portions in the transverse direction CD, and pattern present areas 8g are formed between the pattern absent area 8h in the central portion and the pattern absent areas 8h in both end portions.

In this way, by increasing the jet pressure of the water flow from the 1 st jet nozzles 3-1 to 3-2 in stages from the upstream side toward the downstream side in the conveyance direction MD, it is possible to perform the transfer of the uneven pattern while suppressing the degree of entanglement to the initial web 7 which is not subjected to the treatment of the entanglement of the fibers and has a weak strength, and it is possible to perform the transfer of the uneven pattern while increasing the degree of entanglement to the web 7 which is subjected to the treatment of the entanglement and has an increased strength. This makes it possible to achieve both the transfer (formation) of the uneven pattern and the interlacing of the fibers. In other words, by gradually increasing the jetting pressure of the water stream from low pressure to high pressure, the uneven pattern 55 can be smoothly transferred little by little while avoiding a situation in which the high-pressure water stream is suddenly jetted to the web 7 to damage the web 7, such as scattering of fibers of the web 7, thereby forming the pattern 40 with high visual recognition.

Fig. 14 is a partial cross-sectional view schematically showing a structural example of the semi-finished product 8 on the support 54. In the semi-finished product 8, the uneven pattern 55 of the support 54 is transferred, and a pattern 40 (opening portion) is formed along the uneven pattern 55. In the pattern 40 (opening portion), the gap SG shown in fig. 13 does not exist between the semi-finished product 8 and the uneven pattern 55. This makes the boundary between the semi-finished product 8 and the uneven pattern 55, i.e., the boundary between the non-opening portion and the opening portion clear. This forms the pattern 40 having a high visual recognition. Further, by adjusting the manufacturing conditions (exemplified by the position of the water supply device 2, the number of the 1 st injection nozzles 3, and the pressure of the water flow), the fiber density can be relatively increased in the outline region 8p (corresponding to the outline region 41) surrounding the opening portion of the pattern 40. That is, the boundary between the non-opening portion and the opening portion can be made clearer, whereby the visual recognition of the pattern 40 can be further improved.

The degree of freedom of movement of the fibers contained in the web is higher before interlacing the web than after interlacing the web. Therefore, when the uneven pattern of the support is transferred to the web while the web is entangled, the fibers of the web are likely to move in accordance with the uneven pattern, and the uneven pattern is easily transferred, as compared with the uneven pattern (pattern) of the support which is transferred to the web after the web is entangled. In the present embodiment, since the uneven pattern of the support is transferred to the web 7 while the web 7 is interlaced, the boundaries of the transferred perforated portions 40a can be made clear, and thus the visual recognition of the pattern 40 can be improved. Further, the energy of the water flow of the 1 st injection nozzle 3 can be reduced, and the production efficiency can be improved.

Next, the 2 nd suction drum 6, the 2 nd spray nozzle 4, the downstream side conveyor 14, and the dehydrator 25 perform a post-interlacing process.

Referring to fig. 6, the 2 nd suction drum 6 includes a support body having no uneven pattern on the surface thereof on the outer circumferential surface 6 a. The 2 nd suction drum 6 sucks the semifinished product 8 conveyed from the 1 st suction drum 5 via the support body while rotating the support body about the axis a2, holds the semifinished product on the outer peripheral surface 6a, and conveys the semifinished product to the downstream side conveying device 14. At this time, the blank 8 is conveyed along the surface of the support body such that the 1 st surface 8a faces the inside of the 2 nd suction roller 6 and contacts the outer peripheral surface 6a, and the 2 nd surface 8b on the side opposite to the 1 st surface 8a faces the outside of the 2 nd suction roller 6. Wherein the 1 st side 8a of the semi-finished product 8 corresponds to the 1 st side 7a of the web 7 and the 2 nd side 8b of the semi-finished product 8 corresponds to the 2 nd side 7b of the web 7.

The 2 nd spray nozzle 4 does not spray water (the 2 nd water stream) to the pattern existing region 8g of the intermediate product 8 held on the outer peripheral surface 6a of the 2 nd suction drum 6 but sprays water (the 2 nd water stream) from the 2 nd surface 8b side to the pattern non-existing region 8 h. Thus, the 2 nd spray nozzle 4 does not disturb the transferred pattern (a plurality of perforated portions) 40, and further weaves the fibers of the semi-finished product 8 with each other while maintaining the definition of the boundaries of the perforated portions 40a and the visual identification of the pattern 40, thereby forming the spunlace nonwoven fabric 9 having the pattern 40. In the present embodiment, 1 second injection nozzle 4 is provided as the second injection nozzle 4, but the number thereof is not particularly limited. The 2 nd spray nozzle 4 sprays water from a plurality of nozzle holes arranged in a line linearly along the transverse direction CD and at a constant pitch. The 2 nd suction drum 6 sucks and stably holds the semifinished product 8 in the interlacing while sucking water from the 2 nd surface 8b side to the semifinished product 8 at a position substantially opposed to the 2 nd spray nozzle 4.

Fig. 11 is a diagram schematically showing a configuration example of the 2 nd spray nozzle 4 of the manufacturing apparatus 1. In the present embodiment, 1 second spray nozzle 4 is provided as the second spray nozzle 4. The 2 nd spray nozzle 4 sprays water at high pressure from the 2 nd surface 8b side of the semi-finished product 8 to a pattern non-existing region 8h (fig. 10) of the semi-finished product 8 held on the outer peripheral surface 6a of the 2 nd suction drum 6, thereby further interlacing the fibers of the semi-finished product 8 with each other. Thereby, the strength of the semi-finished product 8 is improved, and the semi-finished product 8 becomes the spunlace nonwoven fabric 9 with patterns. As described above, water is not sprayed toward the pattern existing region 8g (fig. 10).

In order to interleave the pattern nonexistent regions 8h of the semi-finished product 8, the water jet pressure P21 of the 2 nd jet nozzle 4 (water pressure when discharged from the nozzle hole of the 2 nd jet nozzle 4) is preferably 5.0MPa ≦ P21 ≦ 10.0 MPa. Wherein P12 is not more than P21.

Further, if the injection pressure of the water stream of the 1 st injection nozzle 3 is lower than the injection pressure of the water stream of the 2 nd injection nozzle 4, the movement of the fibers of the web 7 that are entangled with each other due to the water stream of the 1 st injection nozzle 3 is smaller than the movement due to the water stream of the 2 nd injection nozzle 4. Therefore, although the fibers are less entangled with each other, the fibers can be finely moved and rearranged in accordance with the uneven pattern. That is, the pattern can be formed while suppressing the degree of the interlace. On the other hand, the water jet pressure of the following 2 nd jet nozzle 4 is high, and therefore the movement of the fibers interlaced with each other is large. Therefore, the fibers are entangled with each other more, that is, can be further entangled. This makes it possible to interlace the fibers to have an appropriate sheet strength without reducing the definition of the boundaries of the perforated portions and the visual recognition of the patterns.

In this way, by spraying water to the pattern-free region instead of the pattern-existing region of the semi-finished product 8 held by the 2 nd suction drum 6, the structural fibers included in the semi-finished product 8 can be intertwined without disturbing the pattern (opening portion) of the pattern-existing region, thereby improving the strength thereof. That is, the spunlace nonwoven fabric 9 having the pattern 40 with an appropriate sheet strength can be produced without reducing the definition of the boundaries of the transferred perforated portions and the visual recognition of the pattern.

Next, referring to fig. 6, the downstream side conveying device 14 includes a downstream side conveying belt 14 a. The downstream side transport device 14 receives the spun lace nonwoven fabric 9 transported by the 2 nd suction roll 6 at a position close to the 1 st suction roll 5 substantially above the 2 nd suction roll 6, and transports the spun lace nonwoven fabric to the dehydrator 25 by the downstream side transport belt 14 a.

The dehydrator 25 includes a conveyor belt 25a and a plurality of suction boxes 25 b. The dewatering machine 25 conveys the spun lace nonwoven fabric 9 conveyed from the downstream side conveyor 14 to the device of the next step by the conveyor belt 25a, and simultaneously sucks water from the spun lace nonwoven fabric 9 on the conveyor belt 25a by the plurality of suction boxes 25 b.

Subsequently, the nonwoven fabric post-treatment apparatus 130 performs a post-treatment process.

As shown in fig. 5, the nonwoven fabric post-treatment apparatus 130 further includes a dryer 26 and a winder 28 at a position downstream of the dehydrator 25. The dryer 26 dries the spun lace nonwoven fabric 9 having moisture absorbed by the dehydrator 25, and thermally bonds the constituent fibers in the spun lace nonwoven fabric 9. The winder 28 winds the spun lace nonwoven 9 sent out from the dryer 26. The spun lace nonwoven fabric 9 wound up by the winder 28 is, for example, wound up and cut, and then subjected to a predetermined treatment, and is used for sanitary products such as absorbent articles, cleaning products, and medical products. The spunlace nonwoven fabric 9 may be directly fed to a process of manufacturing sanitary products such as absorbent articles, cleaning products, and medical products without the winder 28.

As described above, the spunlace nonwoven fabric 9 having the pattern 40 is manufactured.

In the above embodiments and the following examples and comparative examples, the basis weight, thickness and fiber density of a fiber sheet such as a web were measured or calculated by the following methods.

(weight per unit area of fiber sheet)

The measurement objects such as a web, a semi-finished product, and a spun lace nonwoven fabric were each cut into a size of 30cm × 30cm to obtain samples. For this sample, a drying treatment was performed in an air atmosphere of 100 ℃ or higher, and then the mass was measured. The weight per unit area of the sample was calculated by dividing the measured mass by the area of the sample. Here, the average of the weights per unit area of the 10 samples was defined as the weight per unit area of the object to be measured.

(thickness of fiber sheet)

Using a device with 15cm²the thickness of the probe (model FS-60DS, manufactured by Daorhizi Seiki Seisakusho K.K.) was 3g/cm²Under the measurement conditions of the measurement load of (2), the thickness of the object to be measured is measured. Here, the thickness at 3 points was measured for 1 measurement sample, and the average value of the thicknesses at 3 points described above was taken as the thickness of the object to be measured.

(fiber density of the fiber sheet (mass per unit volume: g/cm)³))

The fiber density of the object to be measured (mass per unit volume: g/cm) was calculated by dividing the weight per unit area of the fiber sheet obtained as described above by the thickness of the fiber sheet obtained as described above³)。

(fiber density of the fiber sheet (number of pieces per unit volume: pieces/cm)³))

The sample was cut out to a size of 5mm × 5mm from the area of the object to be measured. For this sample, a 360-degree scan was performed using an X-ray fluoroscopy apparatus (model SKYSCAN 1272, manufactured by Bruker Corporation). Specifically, each time the sample is rotated by 0.5 degrees, X-ray fluoroscopic images are taken, 720X-ray fluoroscopic images in a range of 360 degrees are acquired, and the acquired 720X-ray fluoroscopic images are combined to create a 3D image. From the 3D image, the number of constituent fibers per unit volume of the region to be measured is acquired and is set as the fiber density of the region to be measured (number per unit volume: root/cm)³)。