JP2018178327A - Spunlace non-woven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure pattern visibility of a patterned spunlace non-woven fabric by clarifying a borderline between an aperture and a closed part in a pattern including multiple apertures.SOLUTION: A spunlace non-woven fabric 9 comprises a patterned region 9g in which a pattern 40 exists and non-patterned region 9h other than the patterned region. The pattern includes multiple apertures 40a. In a gray scale image of the spunlace non-woven fabric, a black gradation region and a white gradation region of the patterned region in the image include a gradation having a pixel count at the maximum peak value, and pixel count ratio of a gradation at a center of an intermediate gradation region to the maximum peak pixel count of the black gradation region is 2 or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a spunlace nonwoven fabric.

  Spunlace non-woven fabrics used in various hygiene products such as absorbent articles such as sanitary napkins and disposable diapers, cleaning products such as wet wipers, daily products such as tissue paper, and medical products such as masks are known. ing. Such a spunlace non-woven fabric may be provided with a pattern formed of an uneven portion and an open portion in order to improve design and functionality. For example, Patent Document 1 discloses a method of manufacturing a spunlace nonwoven fabric having a stripe pattern formed of an uneven portion and an open portion.

  In this manufacturing method, after the constituent fibers of the fiber web are entangled (first entanglement), part of the constituent fibers of the fiber web are subjected to hydroentanglement on a support having a regular pattern (concave or convex or open) (2nd confounding). Part of the constituent fibers rearrange to develop multiple stripes having a regular pattern. That is, a spunlace nonwoven fabric having a stripe pattern is formed.

JP, 2013-64226, A

The pattern of the spunlace nonwoven fabric is mainly expressed by the pattern of the uneven portion and / or the pattern of the opening. The pattern of the concavo-convex portion is expressed by the difference in height between the concave portion and the convex portion and the difference in thickness between the concavo-convex portion and the non-concave portion. However, since the thickness of the spunlace nonwoven fabric is thin, the difference in height between the recess and the protrusion and the difference in thickness between the uneven portion and the non-uneven portion are small. Therefore, the pattern of the uneven portion can not be said to be highly visible. On the other hand, the pattern of the opening is represented by the shape of the opening, that is, the color difference between the opening and the non-opening. Therefore, it is expected that the visibility is higher than the pattern of the uneven portion. Therefore, depending on the application, it is desired to express the pattern of the spunlace nonwoven fabric by the pattern of the opening.
However, the pattern of the opening formed by the manufacturing method of Patent Document 1 has the following problems. When forming a pattern by the openings, it is necessary to move the constituent fibers delicately. However, if the pressure of the water flow at the time of the second interlacing is lowered, the constituent fibers can not move so much and It will remain. On the other hand, when the pressure of the water flow is increased, the fibers of short fiber length which are easily moved are separated from the area around the opening, and the fibers of relatively long fiber length increase around the opening. When this happens, the unevenness increases around the opening, making it easier to see the shadow of the unevenness and making it difficult to form a delicate pattern. Therefore, in any case, not only the openings having sufficient openings, but also the openings having insufficient openings and portions where the shading of the unevenness can be easily seen around the openings are formed. Therefore, the boundaries between the openings and the non-openings may look dull and unclear, and the visibility of the pattern may also be reduced. There is room for improvement in the visibility of the boundaries and patterns of the openings of the pattern of the spunlace nonwoven fabric.

  SUMMARY OF THE INVENTION The object of the present invention is, in a spunlace nonwoven fabric having a pattern, in a pattern including a plurality of openings, the boundaries between the openings and the non-openings can be made clear to ensure pattern visibility To provide a flexible spunlace nonwoven fabric.

  The spunlace nonwoven fabric of the present invention is as follows. (1) A spunlaced nonwoven fabric having a pattern having a longitudinal direction, a width direction, and a thickness direction, and having a pattern existing area where the pattern exists and a pattern nonexistent area other than the pattern existing area The pattern includes a plurality of openings penetrating the spunlace nonwoven fabric in the thickness direction in plan view, and the image is obtained by photographing the spunlace nonwoven fabric from above in the thickness direction. When an area having a predetermined area in the portion indicating the pattern existing area in the image is divided into a plurality of pixels, and the color of each pixel is expressed by gray scale having a plurality of gradations from black to white, however, The gray scale has a black tone area on the black side, a white tone area on the white side, and an intermediate tone area between the black tone area and the white tone area. A portion showing the pattern existing area Wherein the black gradation region and the white gradation region each include a gradation having a peak of the maximum value of the number of pixels, and the center of the middle gradation region with respect to the maximum value of the number of pixels of the black gradation region. The ratio of the number of pixels in the gradation of is 2 or less, a spunlace nonwoven fabric. However, the black gradation area is a black area or a gray area close to black, the white gradation area is a white area or a gray area close to white, and the middle gradation area is a gray area. Although the grays close to black and the grays close to white are also gray, they are closer to black and white respectively than grays in the middle gradation area, so here, grays close to black in order to distinguish them from the gray in the middle gradation area And it is described as gray close to white.

  As described above, as the cause of the unclearness of the boundaries of the openings and the decrease in the visibility of the pattern, the openings or openings having insufficient openings in the area of the predetermined area including the pattern of the spunlace nonwoven fabric The existence of the part where the shade of unevenness is easy to see around the part is mentioned. In other words, as a cause, in addition to the near black gray part due to the opening and the near white gray part without the opening, unevenness is caused around the opening or the opening where the opening is insufficient. There is the presence of a dull-looking part, ie a gray part, such as a part where the shade of the is easy to see. Therefore, in the spunlace nonwoven fabric containing the pattern by the openings, more gray parts may occur as compared with the spunlace nonwoven fabric without the pattern by the openings. Therefore, in the present spunlace non-woven fabric, in the pattern existing area, in the gray scale area and the white gradation area in the pattern presence area, in order to relatively reduce the gray area in order to clarify the boundaries of the opening. Each has a maximum value (peak) of the number of pixels, and the ratio of the number of pixels of the central gray level of the middle gray level area to the maximum value of the pixel number of the black gray level area is 2 or less. That is, in the present spunlace nonwoven fabric, the pattern existing region is bipolarized to a gray close to black and a gray close to white, and is formed in the vicinity of the boundary between the opening and the non-opening when forming the opening. The ratio of dark gray to near black gray is relatively small. Therefore, in the present spunlaced nonwoven fabric, it is possible for the user to more easily feel gray that is closer to black than gray, and that closer to white. Thereby, the boundary between the opening and the non-opening can be made clear, and the pattern as a whole can be clearly seen clearly, that is, the visibility of the pattern can be secured.

In the spunlace nonwoven fabric of the present invention, (2) the black gradation area and the white floor relative to the sum of the maximum values of the number of pixels of the black gradation area and the white gradation area in the portion showing the pattern existing area The ratio according to the above (1), wherein the ratio of the value at the central gradation of the middle gradation area to the number of pixels in the central gradation in a straight line connecting the peaks of the tonal area is 0.1 or more. It may be a spunlace nonwoven fabric.
In the present spunlace nonwoven fabric, in the pattern existing region, the value in the central gray level of the middle gray level area and the pixel in the central gray level in the straight line connecting the peaks of the maximum values of the pixels in the black gray level area and the white gray level area. The ratio of the difference from the number to the sum of the number of pixels of the maximum values of the black tone area and the white tone area is 0.1 or more. That is, in the present spunlaced nonwoven fabric, in the pattern existing region, both gray near black and gray near white formed in the vicinity of the boundary between the opening and the non-opening when the opening is formed. The ratio is relatively small. Therefore, the present spunlaced non-woven fabric can make it easier for the user to feel both gray near black and gray near white more strongly than gray. As a result, the boundary between the opening and the non-opening can be made clearer, and the pattern as a whole can be more clearly viewed, that is, the visibility of the pattern can be secured.

In the spunlace nonwoven fabric of the present invention, (3) the spunlace nonwoven fabric includes pulp fibers, and each of the plurality of apertures is the aperture in the in-plane direction parallel to the longitudinal direction and the width direction And a contour region extending in the thickness direction, the fiber density of the pulp fibers in the contour region being higher than the fiber density of the pulp fibers in the pattern non-existence region; The spun lace nonwoven fabric according to 1) or (2) may be used.
When pulp fibers are contained as the constituent fibers of the spunlace nonwoven fabric, the pulp fibers have a short and thin fiber length, so that the adverse effect at the opening when the water flow pressure of the second interlacing is increased is remarkable. Furthermore, after being manufactured, the spunlace nonwoven fabric may be wound into a roll or may be packed in a package and taken out from a narrow outlet. In that case, stress will be generated in the spunlace nonwoven fabric, and there is a possibility that the shape of the concavo-convex portion or the opening portion may be broken by the stress. Therefore, in this spunlace nonwoven fabric, it is said that the fiber density of pulp fibers in the outline area surrounding the opening (example: the number of fibers per unit volume) is higher than the fiber density of pulp fibers in the pattern nonexistent area. It has a feature. Therefore, in the present spunlace nonwoven fabric, in the contour area, the short fiber length of the pulp fiber fills the gaps of constituent fibers having a long fiber length other than the pulp fibers, so that the contour area becomes dense. As a result, the shape of the hole in the hole can not be easily broken, that is, the shape of the hole can be easily maintained. At the same time, it is possible to increase the degree of whiteness of the contoured area, since in the contoured area the pulp fibers fill the asperities and thus make it easier to reflect light. As a result, the outline of the opening, that is, the boundary between the non-opening and the opening can be made clearer, so that it is possible to make the pattern clearly visible. That is, the shape of the openings can be maintained while making the boundaries of the openings clear and ensuring the visibility of the pattern.

The spunlaced nonwoven fabric of the present invention comprises (4) a first outer layer, a second outer layer, and an intermediate layer located between the first outer layer and the second outer layer and containing the pulp fibers. The spun lace non-woven fabric according to the above (3) may be provided.
In the spunlace nonwoven fabric, an intermediate layer containing pulp fibers is sandwiched between the first outer layer and the second outer layer. Therefore, the pulp fiber can be stably held in the outline area of the opening. As a result, it is possible to make the boundaries of the openings clear and to stably maintain the shape of the openings while stably securing the visibility of the pattern.

The spunlace nonwoven fabric according to the present invention may be (5) the spunlace nonwoven fabric according to (4) above, wherein the intermediate layer has a higher fiber density than the first outer layer and the second outer layer.
In the present spunlace nonwoven fabric, the intermediate layer containing pulp fibers has a higher fiber density (e.g. number of fibers per unit volume) than the first outer layer and the second outer layer. Therefore, the pulp fiber can be held more stably in the contour area of the opening. As a result, the boundaries between the openings can be made clear, and the shape of the openings can be maintained more stably while securing the visibility of the pattern more stably.

In the spunlace nonwoven fabric of the present invention, (6) the middle gradation area includes gradation having a local minimum value of the number of pixels, and the local minimum is the number of pixels of the black gradation area and the white gradation area. The spunlace nonwoven fabric according to any one of the above (1) to (5), which is smaller than the maximum value may be used.
In this spunlace nonwoven fabric, the gray scale (grey) of the middle gray scale area has a local minimum (peak downward) of the number of pixels smaller than the maximum of the number of pixels of the black gray scale area and the white gray scale area. ing. Therefore, in the present spunlace nonwoven fabric, it is possible to make the user feel less gray and to make the gray relatively near black or white nearer to be felt more strongly. Thereby, the boundary between the opening and the non-opening can be made clear, and the pattern as a whole can be clearly recognized clearly, that is, the visibility of the pattern can be secured.

In the spunlace nonwoven fabric of the present invention, (7) the plurality of openings include at least two types of openings having different shapes, and the shape of each of the at least two types of openings is a circle or an ellipse The spunlace non-woven fabric according to any one of the above (1) to (6) may be selected from polygons, straight lines, curves, or a combination thereof.
In the present spunlace nonwoven fabric, the shape of the opening is not limited, and may take various shapes such as a circle, an ellipse, a polygon, a straight line, a curved line, or a combination thereof. As these shapes are easy to clearly define the boundaries between the openings and the non-openings, the boundaries of the openings can be made clearer by appropriately selecting these shapes, and the pattern is viewed as a whole. It can be made easy.

In the spunlace nonwoven fabric of the present invention, (8) the non-patterned region is located at the central portion in the width direction of the spunlaced nonwoven fabric, and the longitudinally extending central portion non-present region is the spunlaced nonwoven fabric And the longitudinally extending end pattern non-existing area, the pattern existing area includes the central portion non-existence area and the end pattern non-existence area. It may be a spunlace nonwoven fabric according to any one of the above (1) to (7), which is located between and includes the longitudinally extending end pattern existing area.
In the present spun lace nonwoven fabric, an end pattern existing area is provided between the center pattern non-existing area and the end pattern non-existing area. That is, since the pattern is disposed between the areas where the pattern does not exist, the pattern can be made more prominent, and the visibility of the opening can be more stably secured.

  According to the present invention, in a spunlace nonwoven fabric having a pattern, in the pattern including a plurality of openings, the boundary between the opening and the non-opening can be made clear to ensure the visibility of the pattern. Spunlace non-woven fabric can be provided.

It is a schematic diagram which shows the structural example of the spunlace nonwoven fabric which concerns on embodiment. It is a schematic diagram which shows the example of the pattern of the spunlace nonwoven fabric which concerns on embodiment. It is a graph which shows the relationship of the gradation and the number of pixels in the image which expressed the spunlace nonwoven fabric which concerns on an Example by gray scale. It is a graph which shows the relationship between the gradation and the number of pixels in the image which expressed the spunlace nonwoven fabric which concerns on a comparative example by gray scale. It is a schematic diagram which shows the structural example of the manufacturing apparatus used for the manufacturing method of the spunlace nonwoven fabric which concerns on embodiment. It is a schematic diagram which shows a part of structural example of the manufacturing apparatus used for the manufacturing method of the spunlace nonwoven fabric which concerns on embodiment. It is a cross-sectional schematic diagram which shows a part of structural example of the support body of the 1st suction drum of the manufacturing apparatus of FIG. It is a schematic diagram which shows the structural example of the water supply apparatus of the manufacturing apparatus of FIG. It is a schematic diagram which shows the structural example of the 1st injection | spray nozzle of the manufacturing apparatus of FIG. It is a schematic diagram which shows the structural example of the semi-finished product which concerns on embodiment. It is a schematic diagram which shows the structural example of the 2nd injection | spray nozzle of the manufacturing apparatus of FIG. It is a cross-sectional schematic diagram which shows a process of the web in the water supply apparatus of FIG. It is a cross-sectional schematic diagram which shows the appearance of the web on the support body in the process of FIG. It is a cross-sectional schematic diagram which shows a part of structural example of the semi-finished product on the support body processed with the 1st injection | spray nozzle of FIG.

  Hereinafter, the spun lace nonwoven fabric concerning an embodiment is explained. The application of the spunlace non-woven fabric is not particularly limited. For example, absorbent articles such as sanitary napkins and disposable diapers, cleaning products such as wet wipers, daily products such as tissue paper, medical products such as masks And various other sanitary products.

  FIG. 1: is a schematic diagram which shows the example of a structure of the spunlace nonwoven fabric 9 which concerns on embodiment. FIG. 1 (a) shows a partial plan view of a spunlace nonwoven fabric 9 having a pattern 40, and FIG. 1 (b) shows a partial cross-sectional view of the pattern 40 of FIG. 1 (a). However, the spunlace nonwoven fabric 9 has a longitudinal direction L, a width direction W, and a thickness direction T orthogonal to each other. "Plane view" refers to viewing the spunlace nonwoven fabric 9 in the thickness direction T from the upper surface side. The “in-plane direction” is a direction parallel to a plane including the width direction W and the longitudinal direction L.

  The spunlace nonwoven fabric 9 includes the pattern 40, and further includes a pattern existing area 9g in which the pattern 40 is present and a pattern nonexistent area 9h other than the pattern existing area 9g. The pattern 40 includes a plurality of openings 40 a penetrating the spunlace nonwoven fabric 9 in the thickness direction T in plan view. The details will be described below.

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

  The short fibers are not particularly limited, and include synthetic fibers and natural fibers. In the present embodiment, pulp fibers of natural fibers are mentioned from the viewpoint of absorption of liquid and the like. Although there is no restriction | limiting in particular as a pulp fiber, Wood pulp and non-wood pulp are mentioned. Wood pulp includes, for example, softwood pulp and hardwood pulp. Non-wood pulps include, for example, straw pulp, bagasse pulp, reed pulp, kenaf pulp, mulberry pulp, bamboo pulp, hemp pulp, and cotton pulp.

  On the other hand, fibers other than short fibers (pulp fibers in the present embodiment) are not particularly limited, but synthetic fibers (example: thermoplastic resin fibers), natural fibers, regenerated fibers, or a combination of at least two of these Can be mentioned. The material of the thermoplastic resin fiber includes, for example, polyolefin, polyester, polyamide, and acrylic. Examples of polyolefins include polyethylene (PE), polypropylene (PP), and copolymers based on these. Examples of the polyester include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and copolymers based on these. Examples of the polyamide include nylon 6, nylon 6, 6 and the like. Acrylics include polyacrylonitrile (PAN). When a thermoplastic resin fiber is used, a hydrophilization treatment may be performed, and as the hydrophilization treatment, for example, a treatment using a surfactant, a hydrophilic agent or the like can be mentioned. Natural fibers include, for example, wool and cotton. Examples of regenerated fibers include rayon and acetate. In addition, some or all of the constituent fibers may be core / sheath fibers, side-by-side fibers, composite fibers such as island / sea fibers, hollow fibers, latent crimp or three-dimensional wrinkles of apparent crimp. It may be a crimped fiber.

The proportion of pulp fibers of the spunlace nonwoven fabric 9 is 20% by mass or more from the viewpoint of liquid absorbability, and less than 70% by mass from the viewpoint of maintenance of the structure. The thickness of the spunlace nonwoven fabric 9 is, for example, 0.2 to 5 mm. The basis weight is, for example, 10 to 200 g / m ² . As a fiber density, 0.05-0.3 g / cm < ³ > is mentioned, for example. In the present embodiment, these values are values measured in the pattern non-existence area 9 h.

The layered structure of the spunlace nonwoven fabric 9 is not limited to a single layer or a plurality of layers, but in the present embodiment, a three-layered structure (not shown) is employed. That is, the spunlace nonwoven fabric 9 has a three-layer structure including a first outer layer, a second outer layer, and an intermediate layer located between the first outer layer and the second outer layer. The constituent fibers of the first outer layer and the second outer layer are not particularly limited, but fibers other than the pulp fibers described above can be used mainly from the viewpoint of maintaining the structure. As a fiber density of constituent fibers of the first outer layer and the second outer layer, for example, 0.02 to 0.06 g / cm ³ can be mentioned. The first outer layer and the second outer layer may have the same configuration, for example, the type and ratio of fibers, and the layer structure, or at least one may be different. On the other hand, the constituent fibers of the intermediate layer are not particularly limited, but mainly from the viewpoint of liquid absorbability and retention, the above-described pulp fibers and fibers other than pulp fibers can be used in combination. The proportion of pulp fibers in the intermediate layer is 20% by mass or more and 100% by mass or less from the viewpoint of liquid absorbability and retention. In the present embodiment, the intermediate layer has a higher fiber density than the first outer layer and the second outer layer. As a fiber density of a constituent fiber of the middle class, 0.03-0.25 g / cm ³ is mentioned, for example.

The pattern 40 of the spunlace nonwoven fabric is mainly formed of a plurality of uneven portions and / or a plurality of openings, and in the present embodiment, is mainly formed of a plurality of openings 40a. The opening 40 a is a through hole that penetrates the spunlace nonwoven fabric 9 in the thickness direction T. The plurality of openings 40 a include a plurality of types of openings having different shapes. The shape of each of the plurality of types of openings includes a circle, an ellipse, a polygon, a straight line, a curved line, or a combination thereof. However, straight lines (segments) and curves have a certain thickness. In the present embodiment, the pattern 40 is a watermark such as a lace in which various shapes are combined in a complicated manner 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 20 mm in inner dimension, 0.12 to 100 mm ² in area, and the distance between adjacent openings 40a may be 0.2 -10 mm are mentioned.

  The opening 40 a has a contour region 41 which surrounds the through hole with a predetermined width in the in-plane direction and extends in the thickness direction T. In other words, the contour region 41 is a tubular region having a predetermined width in the in-plane direction along the side wall 40aH surrounding the opening 40a. Here, the predetermined width may be half of the thickness D of the spunlace nonwoven fabric 9, that is, D / 2. However, the outline of the opening 40a at an arbitrary thickness in the thickness direction T connects the end of the fiber on the most open side in the in-plane direction (including the case of the side of the fiber) so as to surround the opening. Let's say The side wall 40aH is a circumferential surface of an opening formed by connecting the contours in each thickness direction T in the thickness direction T. In the case where the distance between the adjacent opening portions 40a is short and the predetermined widths of the both overlap each other, the predetermined width is set to a half of 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 numerical value greater than 2), or the inner dimension d of the in-plane direction of the opening It may be 1 / m (m is a numerical value of 2 or more). Further, the fiber density (number per unit volume) of pulp fibers in the contour region 41 is the fiber density (number per unit volume) of pulp fibers in the pattern nonexistent region 9 h, in other words, pulp fibers in regions other than the contour region 41 More than the fiber density (number per unit volume) of In the case where the spunlace nonwoven fabric 9 has a multi-layer structure, for example, a three-layer structure, the fiber density is evaluated by averaging the fiber density of the three layers in the thickness direction T.

  The pattern existing area 9g is an area of the spunlace nonwoven fabric 9 that is mostly occupied by the pattern 40, that is, an area including the pattern 40 in a plan view, for example, an area expanded outward by a range from the outline of the pattern 40. is there. On the other hand, the pattern non-existing area 9 h is an area excluding the pattern existing area 9 g in the spunlace nonwoven fabric 9 in plan view. In the present embodiment, the pattern existing area 9g and the pattern nonexistent area 9h are an area to be water-flow-entangled and a area not to be water-flow-entangled in the pre-entanglement / transfer step described later. In the present embodiment, the pattern non-existing area 9 h is located at the central portion in the width direction W of the spun lace nonwoven fabric 9 and extends in the longitudinal direction L to the central pattern non-existent area 9 h-a and the width of the spun lace nonwoven fabric 9. An end pattern non-existence area 9 h-b located at an end in the direction W and extending in the longitudinal direction L, and the end pattern non-existence area 9 h-b extends in the width direction W of the spunlace nonwoven fabric 9. It may be disposed at both ends. The pattern existing area 9 g is located between the central pattern non-existing area 9 h-a and the end pattern non-existing area 9 h-b and includes an end pattern existing area 9 g-a extending in the longitudinal direction L.

  In the present embodiment, a watermark such as a race in which various shapes are combined in a complex manner is used as the pattern 40, but the present invention 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 in place of the pattern 40 of the end pattern existing area 9g-a of the spunlace nonwoven fabric 9 of FIG. 1 (a). This pattern is a watermark pattern composed of small openings of various shapes.

Next, clarification of the boundary between the opening 40 a of the pattern 40 and the non-opening will be described.
FIG.3 and FIG.4 is a graph which shows the relationship of the gradation and the number of pixels in the image which expressed the spunlace nonwoven fabric 9 based on Example 1 and the comparative example 1 which are mentioned later by gray scale, respectively. Fig.3 (a) is a figure which shows typically area | region S of the predetermined area extracted from the part which shows the pattern presence area | region 9g among the images which image | photographed the spunlace nonwoven fabric. 3B and 4 divide the area S of the predetermined area in the image taken from the upper side in the thickness direction T of the spunlace nonwoven fabric of Example 1 and Comparative Example 1 under the same conditions into a plurality of pixels, It is a graph which shows the relationship between a gradation (horizontal axis) and the number of pixels (vertical axis) when the color of each pixel is expressed by the gray scale which has several gradation from black to white. The number of pixels is normalized to 1 at the peak of the maximum value. Grayscale, and black tone area A _B black side, and the white tone area A _W white side, and an intermediate tone area A _M between the black tone area A _B and the white tone area A _W Therefore, the black tone area _AB is a black area or a gray area close to black, and the white tone area _AW is a white or a near white gray area (including translucent), and the middle The gradation area _AM is a gray area. In this embodiment, the substantially trisect all gray levels, the 1/3 gradation of black side and black gradation region A _B, the white tone of the 1/3 gradation of the white-side a region _{a W,} the gradation of intermediate 1/3 and the halftone area _{a M.} Specifically, in the present embodiment, the gradation is 256 gradations of 0 to 255, and 0 to 84/85 to 170/171 to 255 are black / middle / white gradation regions. The specific data acquisition method of FIGS. 3 and 4 will be described later.

In the area S1 of the predetermined area in the portion showing the pattern existing area 9g of the embodiment 1 of FIG. 3A, as shown in FIG. 3B, the black gradation area _AB and the white gradation area _AW are The gradations G _BM1 and G _WM1 having the peaks of the maximum values P _BM1 and P _WM1 of the number of pixels, respectively, are included. Here, a black tone area A _B and white gray scale region A _W both have a peak distinct maxima number of pixels, and said. Then, the number of black pixels grayscale region _{A B} relative maxima _{P BM1,} the ratio RG1 number of pixels _{P MM1} in the gradation _{G MM1} of the center of the halftone region is 2.0 or less. Specifically, in FIG. 3B, (G _BM1 , P _BM1 ), (G _WM1 , P _WM1 ), and (G _MM1 , P _MM1 ) are (77, 0.43) and (191, 1), respectively. .00), (127, 0.57). And, RG1 = P _MM1 / P _BM1 = 0.57 / 0.43 = 1.3 ≦ 2.0.

On the other hand, in the region S2 (= S1) of the predetermined area in the portion showing the pattern existing region of Comparative Example 1 of FIG. 4A, as shown in FIG. 4B, the white gradation region _AW has the pixel count The gradation G _WM2 having the peak of the maximum value P _WM2 of However, the black tone area A _B can not be said to contain a tone having a peak maximum value of the number of pixels. If a black tone area A _B is unclear while also including gradation G _BM2 having a peak maxima P _BM2 number of pixels, even if it is possible that the number of black pixels grayscale region A _B The ratio RG1 of the number of pixels P _MM2 in the gray scale G _{MM2 at} the center of the middle gray scale area to the local maximum value P _BM2 of is larger than 2.0 and not smaller than 2. Specifically, in FIG. 4B, (G _BM2 , P _BM2 ), (G _WM2 , P _WM2 ), and (G _MM2 , P _MM2 ) are (81, 0.20) and (191, 1), respectively. .00), (127, 0.42). And it is RG1 = _PMM2 / _PBM2 = 0.42 / 0.20 = 2.1> 2.0.

As described above, the spunlaced non-woven fabric having a pattern is an aperture having insufficient apertures, in addition to a gray portion close to black due to the apertures and a gray portion close to white not being apertured. There is also a dull visible part, i.e. a gray part, due to the part where the shading of the asperities tends to be visible around the part or opening. That is, in the spunlace nonwoven fabric containing the pattern due to the openings, more gray parts may occur as compared with the spunlace nonwoven fabric not containing the pattern due to the openings. Accordingly, the spun lace nonwoven fabric 9, in order to relatively reduce the gray area, the pattern existing region 9 g, the gradation of the black tone area A _B and white gray scale region A _W, the maximum value P of each pixel number _{BM1, P WM1} has a (peak) with respect to the black gradation region _a maximum value _{P BM1} number of pixels _B, the ratio of the intermediate gradation area _{a M} of the center tone of the pixel number _{P MM1} RG1 is set to 2 or less . That is, in the spunlace nonwoven fabric 9, the pattern existing area 9 g is polarized into a gray close to black and a gray close to white, and the open portion 40 a and the non-open portion to the gray portion close to black. The ratio of the gray part formed near the boundary of the is relatively small. Therefore, in the spunlace nonwoven fabric 9, it is possible to make the user feel the gray close to black more strongly than the gray close to white, rather than gray. Thereby, the boundary between the opening 40a and the non-opening can be made clear, and the pattern as a whole can be made clearly visible, that is, the visibility of the pattern can be secured.

In a preferable embodiment of the present embodiment, in the region S1 of FIG. 3 (a), as shown in FIG. 3 (b), a black tone area A _B and the maximum value of the number of pixels white tone area A _W of to the sum _(P BM1 ₊ P _WM1), black tone area _{a B} and the value _{P MM1} 'centered floor main gradation _{G MM1} halftone area in a straight line E1 connecting the peaks between the white tone area _{a W} tone difference .DELTA.1, the ratio RG2 the pixel number _{P MM1} in _{G MM1} is 0.10 or more. Specifically, in FIG. 3B, (G _BM1 , P _BM1 ), (G _WM1 , P _WM1 ), (G _MM1 , P _MM1 ), and (G _MM1 , P _MM1 ') are respectively (77, 0.43), (191, 1.00), (127, 0.57), (127, 0.76). Then, RG2 = Δ1 / (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 sum of the maximum value of the number of black pixels tone area _{A B} and white gray scale region _{A W (P BM2} pixels in + _P for _WM2), black tone area _{a B} and white gray scale region _{a W} central gradation value at _{G MM2 P MM2} 'centered gradation _{G MM2} halftone area in a straight line E2 connecting the peaks with each other The ratio RG2 of the difference Δ2 with the number P _MM2 is less than 0.10 and not more than 0.10. Specifically, in FIG. 4 (b), ( _G.sub.BM2 , _P.sub.BM2 ), ( _G.sub.WM2 , _P.sub.WM2 ), ( _G.sub.MM2 , _P.sub.MM2 ), ( _G.sub.MM2 , _P.sub.MM2 ') are respectively (81, 0.20), (191, 1.00), (127, 0.42), (127, 0.53). Then, RG2 = Δ2 / (P _BM2 + P _WM2 ) = (0.53−0.42) / (0.20 + 1.00) = 0.092 <0.10.

Thus, the spun lace nonwoven fabric 9, in a pattern existing region 9 g, intermediate floors in the black tone area _{A B} and white gray scale region _A maximum value of the number of pixels in _{W P BM1,} straight E1 connecting the peaks between the _{P WM1} the sum of the difference Δ1 between the number of pixels P _MM1 in the value P _{MM1 'centered} tone at the center gradations, the number of pixels of the maximum value of the black tone area a _B and white tone area a _W of gradation area a _M (The ratio to P _BM1 + P _WM1 is 0.10 or more. That is, in the spunlace nonwoven fabric 9, the openings 40 a and the non-blackish gray and the near-white gray in the pattern existing region 9 g are not Since the ratio of the gray portion formed near the boundary with the opening is relatively small, the spunlace nonwoven fabric 9 has a gray and black that is closer to black than gray for the user. Both near gray colors can be felt more strongly, which makes it possible to make the boundary between the opening 40a and the non-opening clearer and to make the pattern clearly visible as a whole. , I.e., the visibility of the pattern can be secured.

In a preferable embodiment of the present embodiment, as shown in FIG. 3 (b), the intermediate tone area _{A M,} the number of the minimum value _{P MMIN1} (here, downward peak) of the pixel gray scale _{G MMIN1} having including. Minimum value _{P MMIN1} include black tone area _{A B} and white gray scale region _{A W} maximum value _P of the number of pixels _BM1, less than _{P WM1.} Specifically, in FIG. 3B, (G _BM1 , P _BM1 ), (G _WM1 , P _WM1 ), and (G _MMIN1 , P _MMIN1 ) are (77, 0.43) and (191, 1), respectively. .00), (94, 0.42). Then, P _BM1 , P _WM1 = 0.43, and 1.00> 0.42 = P _MMIN1 .

On the other hand, as shown in FIG. 4 (b), the intermediate tone area _{A M,} (in this case, downward peak) number of minimum values _{P MMIN2} pixels not be said that contains gradation _{G MMIN2} with. In other words, the black tone area _{A B} and a small minimum value _{P MMIN2} than white maxima _P number of pixels of the grayscale region _{A W BM1, P WM1} is absent.

Thus, the spun lace nonwoven fabric 9, the gradation of halftone area _{A M} (gray), the maximum value _P of the black tone area _{A B} and white gray scale region _{A W BM1,} less than _{P WM1,} pixel It has a local minimum value _PMMIN1 (peak downward) of the number. Therefore, the spunlace nonwoven fabric 9 can make it difficult for the user to feel gray, and can make gray relatively near black or white nearer to be felt more strongly. Thereby, the boundary between the opening 40 a and the non-opening can be made clear, and the pattern as a whole can be made clearly visible, that is, the visibility of the pattern can be secured.

  In addition, when pulp fibers are included as the constituent fibers of the spunlace nonwoven fabric 9, when the pressure of the hydroentangling water flow is increased, the pulp fibers have a short, thin, and light fiber length, so it is easy to see from the periphery of the opening. Because it is moved to another place, the boundary of the opening tends to be unclear. Furthermore, the spunlace nonwoven fabric 9 may be wound into a roll after being manufactured, or may be packed into a package and taken out from a narrow outlet, and the stress generated at that time makes the shape of the opening 40a There is a risk of collapse. Therefore, as a preferable mode of the present embodiment, in the spunlace nonwoven fabric 9, the fiber density (number per unit volume) of the pulp fiber in the outline area 41 surrounding the opening 40a is the pulp fiber in the pattern nonexistent area 9h. It has the feature of being high compared with the fiber density (number per unit volume). Therefore, in the spun lace nonwoven fabric 9, in the contour area 41, since the short fibers having short fiber lengths fill gaps of constituent fibers having a long fiber length other than the pulp fibers, the contour area 41 is dense. As a result, it is possible to make the shape of the openings of the openings 40a less likely to collapse, that is, to easily maintain the shape of the openings. At the same time, in the contour area 41, since the pulp fiber fills the unevenness and thus the light is easily reflected, the degree of whiteness of the contour area 41 can be enhanced. As a result, the outline of the opening 40a, that is, the boundary between the non-opening and the opening 40a can be made clearer, which makes it possible to make the pattern clearly visible. That is, it is possible to make the boundary of the opening 40 a clear and maintain the shape of the opening 40 a while securing the visibility of the pattern 40.

  Moreover, as a preferable aspect of the present embodiment, in the spunlace nonwoven fabric 9, the shape of the opening 40 a can take various shapes such as a circle, an ellipse, a polygon, a straight line, a curve, or a combination thereof. . Since it is easy to clearly form the boundary between the opening 40a and the non-opening in these shapes, the boundary of the opening 40a can be made clearer by appropriately selecting these shapes. It becomes possible to make it easy to visually recognize the pattern 40 as a whole.

  Further, as a preferable mode of the present embodiment, in the spunlace nonwoven fabric 9, the end pattern existing area 9 g-a is formed between the central pattern non-existing area 9 h-a and the end pattern non-existing area 9 h-b. Have. That is, since the pattern is disposed between the two regions where the pattern 40 does not exist, the pattern 40 can be made more distinctive. As a result, the boundaries between the openings 40a can be made clearer, and the visibility of the pattern 40 can be secured more stably.

  Further, as a preferable mode of the present embodiment, in the spunlace nonwoven fabric 9, the middle layer containing pulp fibers is sandwiched between the first outer layer and the second outer layer. Therefore, the pulp fiber can be stably held in the outline area 41 of the opening 40a. As a result, the boundary of the opening 40a can be made clear, and the shape of the opening 40a can be stably maintained while stably securing the visibility of the pattern 40.

  Further, as a preferable mode of the present embodiment, in the spunlace nonwoven fabric 9, the middle layer containing pulp fibers has a higher fiber density (number per unit volume) than the first outer layer and the second outer layer. There is. Therefore, the pulp fiber can be held more stably in the contour area 41 of the opening 40a. Thereby, the boundary of the opening 40 a can be made clear, and the shape of the opening 40 a can be more stably maintained while more stably securing the visibility of the pattern 40.

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

  In the method of producing the spunlace nonwoven fabric 9 having the pattern 40, a web forming process for producing the web 7, a wetting and dewatering process for making the web 7 wet and dewatering, and transferring the concavo-convex pattern while intermingling the web 7 Pre-entanglement / transfer step of forming a semi-finished product 8 having a pattern 40, post-interlacing step of further interlacing the semi-finished product 8 to form a spunlace nonwoven fabric 9 having a pattern 40, post-treatment steps of the spunlace nonwoven fabric 9 And.

  FIG. 5: is a schematic diagram which shows the structural example of the manufacturing apparatus used for the manufacturing method of the spunlace nonwoven fabric which concerns on embodiment. The manufacturing apparatus 1 includes a web forming apparatus 110, a nonwoven fabric forming apparatus 120, and a nonwoven fabric post-processing apparatus 130. In the manufacturing apparatus 1, the conveyance direction of the web 7, the semifinished product 8 and the spunlace nonwoven fabric 9 is MD, and the direction perpendicular to the conveyance direction MD, that is, the width direction of the web 7 etc. is the transverse direction CD. The transport direction MD and the transverse direction CD are the same as the longitudinal direction L and the width direction W of the spunlace nonwoven fabric 9.

First, the web forming process is performed by the web forming apparatus 110.
The web forming apparatus 110 is an apparatus for forming the web 7 from fibers, and includes a first card machine 21, an air laid machine 22, a second card machine 23, and a web transfer apparatus 11. The first card machine 21 inputs the fibers constituting the first fiber laminate 7-1 from a feeder to form the first fiber laminate 7-1. The first fiber laminate 7-1 finally becomes the first outer layer. The air laid machine 22 inputs the fibers constituting the second fiber laminate 7-2 from the feeder to form the second fiber laminate 7-2 on the first fiber laminate 7-1. The second fiber laminate 7-2 finally becomes an intermediate layer. The second card machine 23 inputs the fibers constituting the third fiber laminate 7-3 from the feeder to form the third fiber laminate 7-3 on the second fiber laminate 7-2. Do. The third fiber laminate 7-3 finally becomes the second outer layer. And the web 7 is formed by laminating | stacking these 1st-3rd fiber laminated bodies 7-1 to 7-3. The web 7 is delivered from the web conveyance belt 11 a of the web conveyance device 11 to the nonwoven fabric forming device 120. However, although the web 7 is a lamination of a plurality of fiber laminates, the entanglement treatment for interlacing fibers is not performed. In addition, each fiber laminated body which comprises the web 7 can be arbitrarily selected by the use etc. of the nonwoven fabric manufactured.

The fibers of the web 7 can be optionally selected depending on the application of the non-woven fabric to be produced. The fiber density of the web 7 is, for example, about 2 to 4 × 10 ⁻³ g / cm ³ . The basis weight of the web 7 is, for example, about ²⁰ to 70 g / m ² . The thickness of the web 7 is, for example, about 7 to 20 mm.

  Next, the non-woven fabric forming apparatus 120 executes a wetting and dewatering process, a pre-intermingling and transferring process, and a post-intermingling process. FIG. 6 is a schematic view showing the non-woven fabric forming apparatus 120 of the configuration example of the manufacturing apparatus of FIG. The nonwoven fabric forming apparatus 120 includes an upstream conveying device 13, a first suction drum 5, a water supply device 2, a first jet nozzle 3, a second suction drum 6, and a second jet nozzle 4. , The downstream transport device 14, and the dehydrator 25.

  First, the upstream side conveying device 13, the first suction drum 5, and the water supply device 2 execute the wetting and dewatering steps. The upstream side transport device 13 transports the web 7 formed by the web forming device 110 by the upstream side transport belt 13 a, and the transport direction is changed upward by the direction changing roll 12 to the first suction drum 5. Transport At this time, the web 7 is such that the first surface 7a of the web 7 faces the outside of the upstream conveyance device 13, and the second surface 7b opposite to the first surface 7a contacts the upstream conveyance belt 13a. It is transported.

  Next, the first suction drum 5 is provided with a support having an uneven pattern on the surface on the outer peripheral surface 5a. The first suction drum 5 sucks the web 7 conveyed by the upstream conveying device 13 through the support while rotating the support around the axis A1, and holds the web 7 on the outer circumferential surface 5a, 2. Transport to suction drum 6 of 2. At this time, the web 7 is supported such that the first surface 7 a faces the outside of the first suction drum 5 and the second surface 7 b faces the inside of the first suction drum 5 and contacts the outer circumferential surface 5 a. It is transported along the surface of the body.

  FIG. 7 is a view schematically showing a part of a cross section of a configuration example of the support 54. As shown in FIG. As shown in FIG. 7, the support 54 includes a base 56 and a concavo-convex pattern 55 formed on the surface of the base 56. The base 56 is disposed on the outer peripheral surface 5 a and has a plurality of mesh-like holes through which liquid or gas can pass. The concavo-convex pattern 55 is a recess or a protrusion having a shape of a pattern, and in the present embodiment, is a protrusion having a shape of a predetermined pattern. Here, the height h of the convex portion can be arbitrarily selected depending on the use of the non-woven fabric to be produced, the shape of the pattern, and the like, but, for example, 0.1 to 10 mm can be mentioned.

  Next, referring to FIG. 6, the water supply device 2 applies water to the web 7 held on the outer peripheral surface 5 a of the first suction drum 5 from the first surface 7 a side, The space existing in the water is filled with water to wet the web 7. The first suction drum 5 sucks in water from the second surface 7b side of the wetted web 7 and dewaters the water from the second surface 7b. That is, the water filling the space between the fibers of the web 7 is sucked by the first suction drum 5 and generally removed.

  FIG. 8 is a view schematically showing a configuration example of the water supply device 2 of the manufacturing device 1. The water supply device 2 includes, for example, an opening 2a provided linearly in a direction parallel to the transverse direction CD, and the low pressure water sent from a fluid source (not shown) is not pressurized but is directly output from the opening 2a. Release as water 30. This water 30 is applied to the web 7 by free fall as it is. In addition, since the water supply device 2 is not intended to entangle the fibers of the web 7 with water but to contain water in the web 7, the water supply device 2 should inject water at high pressure. Instead of watering the web 7, water is applied. Therefore, as shown in FIG. 8, water may be allowed to freely fall on the web 7 from a position near the web 7, or water sprayed by spraying may be applied to the web 7.

  Here, the pressure of water applied by the water supply device 2 (water pressure when discharged from the opening of the water supply device 2) is determined by the thickness of the web 7 and the kind of structural fiber, but the web 7 is moistened. What is necessary is, in order not to cause the web 7 to be substantially entangled, it may be greater than 0.1 MPa (atmospheric pressure) and 0.8 MPa or less, preferably greater than 0.1 MPa (atmospheric pressure) and 0.5 MPa. The amount of water to be supplied to the web 7 is determined by the thickness of the web 7 and the type of structural fiber, but the web 7 may be wetted, and 100 to 150 L / min can be mentioned. Thus, by suppressing the pressure of the water applied from the water supply device 2 to a low level, the water of the water supply device 2 scatters the fibers or the formation is disturbed from the web 7 which is not subjected to the process of interlacing the fibers. Can be prevented.

  FIG. 12 is a cross-sectional view schematically showing the web 7 being wetted by the water supply device 2 and dewatered by the first suction drum 5. First, in (a) of FIG. 12, the web 7 is disposed on the outer peripheral surface 5 a of the first suction drum 5. At this time, the web 7 contains many spaces between fibers, and is in a bulky state, that is, in a thick state. Next, in FIG. 12 (b), the water supply device 2 applies water to the web 7. At this time, the space between the fibers of the web 7 is filled with water, but the bulky state (thick state) does not change. And in FIG.12 (c), when the water contained in the web 7 is attracted | sucked by the 1st suction drum 5, the web 7 is spin-dried. At this time, since the water contained in the web 7 and the fibers of the web 7 are chemically bonded (hydrogen bonded), the fibers of the web 7 are pulled by the water sucked into the first suction drum 5. Head toward the first suction drum 5 side. Alternatively, the fibers of the web 7 are physically pressed by the water sucked into the first suction drum 5 and directed to the first suction drum 5 side. Thus, the fibers of the web 7 are attracted to the first suction drum 5 side as the water moves, and the space between the fibers of the web 7 is rapidly reduced to reduce the bulk of the web 7 as a whole (see FIG. By reducing the thickness), the fiber density of the web 7 is increased.

The fiber density of the web 7 immediately after being wetted by the water supply device 2 and dewatered by the first suction drum 5 is about 4 to 8 × 10 ⁻² g / cm ³ . When the fiber density is too high, it is difficult to move the fibers of the web 7 by the water flow of the first injection nozzle 3 in the post process. If the fiber density is too low, the impact of the water flow of the first jet nozzle 3 may cause the fibers of the web 7 to be scattered, which may adversely affect formation. This fiber density is higher than the fiber density before being processed by the water supply device 2. The basis weight of the web 7 is about ²⁰ to 70 g / m ² , and the thickness of the web 7 is about 1 to 5 mm.

  Thus, by supplying water from the water supply device 2 to the web 7 and dewatering the web 7 with the first suction drum 5, the web 7 can be thinned and the fiber density of the web 7 can be easily set to the above-mentioned predetermined range It is possible to In addition, since the web 7 is dewatered and the amount of water contained in the web 7 is extremely small, the energy of the water jetted from the first jet nozzle 3 in the post process can be efficiently transmitted to the web 7. Thus, when the fiber density of the web 7 is in the above-mentioned predetermined range, the fibers are in close contact with each other, so that the bonds between the fibers become stronger than immediately after forming the web 7 (but compared to the case where the web 7 is entangled). Binding is weak). In addition, the fibers on the surface of the web 7 are almost fluffed and lie along the surface. Therefore, when the concavo-convex pattern is transferred to the web 7 while intermingling the fibers of the web 7 in a post process, the fibers of the web 7 are scattered by the impact of the water flow jetted from the first jet nozzle 3 and the fibers of the web 7 It can be suppressed that the density becomes uneven and the formation of the web 7 is disturbed.

  FIG. 13 is a cross-sectional view schematically showing the appearance of the web 7 on the concavo-convex pattern 55 in the wetting and dewatering steps of FIG. When the web 7 is disposed on the concavo-convex pattern 55 of the support 54, the web 7 is formed into the concavo-convex pattern 55 by being wetted by the water supply device 2 and sucked and dewatered by the first suction drum 5. A roughly corresponding deformation is made, whereby a temporary pattern 42 is formed on the web 7. In the temporary pattern 42, a gap SG or the like exists between the concavo-convex pattern 55 and the web 7, and it can not be said that the concavo-convex pattern 55 is transferred to the web 7. However, since the temporary pattern 42 and the concavo-convex pattern 55 have shapes that substantially fit each other, the web 7 can be fixed on the concavo-convex pattern 55. As a result, when the water flow is injected onto the web 7 by the first injection nozzle 3 in a post process, the web 7 can be prevented from moving by the jet.

  Next, the first suction drum 5 and the first jet nozzle 3 execute the front entanglement / transfer step. Referring to FIG. 6, the first injection nozzle 3 injects water (first water flow) from the first surface 7 a side to the web 7 held on the outer peripheral surface 5 a of the first suction drum 5. Do. That is, while the fibers of the web 7 are entangled, the first jet nozzle 3 presses the web 7 against the concavo-convex pattern 55 of the support 54 to transfer the concavo-convex pattern 55 to the web 7. Thereby, a semifinished product 8 having a pattern (a plurality of openings) 40 is formed. In the present embodiment, two first jet nozzles 3-1 and 3-2 are provided in order from the upstream side along the conveyance direction of the web 7 as the first jet nozzles 3, but the number thereof There is no particular restriction on The first spray nozzles 3-1 and 3-2 spray water from one row of a plurality of nozzle holes disposed linearly and at a constant pitch along the transverse direction CD. The first suction drum 5 sucks water at a position generally facing the first jet nozzles 3-1 to 3-2 from the second surface 7b side with respect to the web 7 being entangled and transferred. , Securely suction the web 7 and hold it stably. In the semi-finished product 8, a pattern existing area of the area where the pattern exists and a pattern non-existing area of the area where the pattern does not exist are formed.

  The injection pressure of the water flow of the first injection nozzles 3-1 to 3-2 becomes higher as it proceeds in the conveyance direction MD of the web 7. Specifically, as the injection pressure of the water flow of the first injection nozzle 3-1 (water pressure when discharged from the nozzle hole of the first injection nozzle 3-1) P11, the support 54 having the concavo-convex pattern 55 In order to start transfer of the concavo-convex pattern 55 to the web 7 while starting interlacing of the web 7 above, the pressure of water of the water supply device 2 is set higher, and 1.0 MPa ≦ P11 ≦ 6.0 MPa is preferable. As the jet pressure of the water flow of the first jet nozzle 3-2 (water pressure when discharged from the nozzle hole of the first jet nozzle 3-2) P12, the web 7 is formed on the support 54 having the concavo-convex pattern 55. In order to transfer the concavo-convex pattern 55 to the web 7 while advancing the entanglement, 3.0 MPa ≦ P12 ≦ 7.0 MPa is preferable. However, it is P11 <P12.

  FIG. 9 is a view schematically showing a configuration example of the first injection nozzle 3 of the manufacturing apparatus 1. In FIG. 9, only the most upstream first injection nozzle 3-1 is shown, and the first injection nozzle 3-2 is omitted. The first jet nozzles 3-1 and 3-2 jet water from the first surface 7 a side of the web 7 at a high pressure to the web 7 held on the outer peripheral surface 5 a of the first suction drum 5. While forming the pattern 40 to which the uneven | corrugated pattern 55 was transcribe | transferred on the web 7, the fibers of the web 7 are entangled. As a result, the web 7 becomes a semifinished product 8 having the pattern 40.

  FIG. 10 is a view schematically showing a configuration example of the semifinished product 8 having the pattern 40. As shown in FIG. The semifinished product 8 has a pattern existing area 8g having a pattern 40 extending along the transport direction MD and a pattern non-existence area 8h not having the pattern 40 extending along the transport direction MD. In the example of this figure, pattern non-existence area 8h is formed in the central part and both ends of cross direction CD, pattern existing area 8g between pattern non-existence area 8h of central part and pattern non-existence area 8h at both ends. Is formed.

  Thus, the entanglement of fibers is processed by stepwise increasing the jet pressure of the water flow of the first jet nozzles 3-1 to 3-2 from the upstream side to the downstream side along the transport direction MD. The uneven pattern can be transferred while suppressing the degree of entanglement low for the weak initial web 7 with low strength, and the degree of entanglement is increased for the web 7 where the entanglement advances and the strength increases. At the same time, transfer of the concavo-convex pattern can be further advanced. Thereby, transfer (formation) of a concavo-convex pattern and entanglement of fibers can be compatible. In other words, by gradually increasing the jet pressure of the water flow from low pressure to high pressure, the web 7 is not damaged as the high pressure water flow is jetted to the web 7 and the fibers of the web 7 are scattered. It is possible to form the pattern 40 with high visibility by gradually advancing the transfer of the concavo-convex pattern 55 little by little.

  FIG. 14 is a view schematically showing a cross section of a part of the configuration example of the semifinished product 8 on the support 54. As shown in FIG. In the semifinished product 8, the concavo-convex pattern 55 of the support 54 is transferred, and the pattern 40 (opening portion) is formed along the concavo-convex pattern 55. In the pattern 40 (opening portion), the gap SG as shown in FIG. 13 does not exist between the semi-finished product 8 and the concavo-convex pattern 55. As a result, the boundary between the semifinished product 8 and the concavo-convex pattern 55, that is, the boundary between the non-opening and the opening becomes clear. Thus, a pattern 40 with high visibility is formed. In the outline area 8p (corresponding to the outline area 41) surrounding the opening of the pattern 40 by adjusting the manufacturing conditions (eg, the position of the water supply device 2, the number of the first injection nozzles 3 and the pressure of the water flow). The fiber density can be relatively high. That is, the boundary between the non-opening portion and the opening portion can be made clearer, whereby the visibility of the pattern 40 can be made higher.

  The degree of freedom of movement of fibers contained in the web is higher before entanglement of the web than after entanglement of the web. Therefore, rather than transferring the concavo-convex pattern (pattern) of the support to the web after entanglement of the web, it is better to transfer the concavo-convex pattern of the support to the web while interlacing the web depending on the concavo-convex pattern. It is easy to move and transfer of the concavo-convex pattern is easy. In the present embodiment, since the concavo-convex pattern of the support is transferred to the web 7 while intermingling the web 7, the boundaries of the transferred openings 40a can be made clear, whereby the visibility of the pattern 40 can be increased. Furthermore, the energy of the water flow of the first injection nozzle 3 can be reduced, and the production efficiency can be improved.

Next, the second suction drum 6, the second jet nozzle 4, the downstream side conveying device 14, and the dehydrator 25 perform a post-confusing process.
Referring to FIG. 6, the second suction drum 6 is provided on the outer peripheral surface 6a with a support having no uneven pattern on the surface. The second suction drum 6 sucks the semifinished product 8 conveyed from the first suction drum 5 through the support while holding the support on the outer peripheral surface 6a while rotating the support around the axis A2. While conveying to the downstream side conveyance device 14. At this time, in the semifinished product 8, the first surface 8a faces the inside of the second suction drum 6 and contacts the outer peripheral surface 6a, and the second surface 8b opposite to the first surface 8a is the second suction. It is conveyed along the surface of the support so as to face the outside of the drum 6. However, the first surface 8 a of the semifinished product 8 corresponds to the first surface 7 a of the web 7, and the second surface 8 b of the semifinished product 8 corresponds to the second surface 7 b of the web 7.

  The second injection nozzle 4 does not inject water (second water flow) to the pattern existing area 8g in the semifinished product 8 held on the outer peripheral surface 6a of the second suction drum 6, and the pattern nonexistent area Water (second water flow) is injected from the second surface 8 b side to 8 h. As a result, the second jet nozzle 4 does not disturb the transferred pattern (a plurality of openings) 40, while maintaining the apparentness of the boundary of the opening 40a and the visibility of the pattern 40. The fibers of the product 8 are further entangled to form a spunlaced nonwoven fabric 9 having a pattern 40. In the present embodiment, one second injection nozzle 4 is provided as the second injection nozzle 4, but the number thereof is not particularly limited. The second spray nozzle 4 sprays water from a row of nozzle holes arranged at a linear and constant pitch along the transverse direction CD. The second suction drum 6 reliably sucks the semi-finished product 8 while suctioning water from the second surface 8 b side with respect to the semi-finished product 8 being entangled, at a position generally facing the second injection nozzle 4 And hold stably.

  FIG. 11 is a view schematically showing a configuration example of the second injection nozzle 4 of the manufacturing apparatus 1. In the present embodiment, one second injection nozzle 4 is provided as the second injection nozzle 4. The second injection nozzle 4 is on the second surface 8 b side of the semifinished product 8 with respect to the non-patterned area 8 h (FIG. 10) of the semifinished product 8 held on the outer peripheral surface 6 a of the second suction drum 6. The water is jetted at a high pressure from the above to further entangle the fibers of the semifinished product 8 with each other. Thereby, the semi-finished product 8 is enhanced in strength and becomes a spunlace nonwoven fabric 9 having a pattern. As described above, water is not jetted toward the pattern existing area 8g (FIG. 10).

  Regarding the jet pressure of the water flow of the second jet nozzle 4 (water pressure when discharged from the nozzle hole of the second jet nozzle 4) P21, in order to advance the entanglement of the pattern non-existence area 8h of the semifinished product 8, 5 It is preferable that 0 MPa ≦ P21 ≦ 10.0 MPa. However, it is P12 <= P21.

  In addition, when the injection pressure of the water flow of the first injection nozzle 3 is lower than the injection pressure of the water flow of the second injection nozzle 4, compared with the water flow of the second injection nozzle 4, the pressure of the first injection nozzle 3 The movement of intermingling of the fibers of the web 7 by the water flow is reduced. Therefore, although there is little entanglement between the fibers, the fibers can be delicately moved and rearranged according to the concavo-convex pattern. That is, the formation of the pattern can be advanced while suppressing the degree of entanglement. On the other hand, since the injection pressure of the water flow of the subsequent 2nd injection | spray nozzle 4 is high, the movement of the entanglement of fibers becomes large. Therefore, the entanglement between fibers increases, that is, the entanglement can be further advanced. Thus, the fibers can be entangled so as to have appropriate sheet strength without lowering the clarity of the boundaries of the openings and the visibility of the pattern.

  As described above, the pattern of the pattern existing area is formed by injecting water to the pattern non-existing area without injecting water to the pattern existing area of the semifinished product 8 held by the second suction drum 6. It is possible to entangle the constituent fibers contained in the semifinished product 8 and to increase the strength thereof without disturbing the hole portion). That is, the spunlace nonwoven fabric 9 having the pattern 40 having an appropriate sheet strength can be manufactured without lowering the clarity of the boundary of the transferred opening and the visibility of the pattern.

  Next, referring to FIG. 6, the downstream side conveyance device 14 includes a downstream side conveyance belt 14 a. The downstream side conveyance device 14 receives the spunlace nonwoven fabric 9 conveyed by the second suction drum 6 at a position near the first suction drum 5 substantially on the upper side of the second suction drum 6 and carries out the downstream side conveyance. The sheet is conveyed to the dehydrator 25 by the belt 14a.

  The dehydrator 25 includes a conveyance belt 25a and a plurality of suction boxes 25b. The dehydrator 25 transports the spunlace nonwoven fabric 9 transported from the downstream transport device 14 to the equipment of the next process by the transport belt 25a, and removes moisture from the spunlace nonwoven fabric 9 on the transport belt 25a by the plurality of suction boxes 25b. Aspirate.

Next, the non-woven fabric post-treatment device 130 executes a post-treatment process.
As shown in FIG. 5, the non-woven fabric post-treatment apparatus 130 further includes a dryer 26 and a winder 28 on the downstream side of the dehydrator 25. The dryer 26 dries the spunlace nonwoven fabric 9 whose moisture has been sucked by the dehydrator 25 and heat-seals constituent fibers in the spunlace nonwoven fabric 9. The winder 28 winds the spunlace nonwoven fabric 9 carried out of the dryer 26. The spunlace nonwoven fabric 9 taken up by the winder 28 is, for example, subjected to predetermined processing after being taken out and cut, and used in sanitary goods such as absorbent articles, cleaning articles and medical articles. Ru. Note that the spun lace nonwoven fabric 9 may be transported to a process of manufacturing sanitary products such as absorbent articles, cleaning articles, and medical articles without the winding machine 28.

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

  In each of the above-described embodiments and the following examples and comparative examples, the basis weight, thickness and fiber density of a fiber sheet such as a web are measured or calculated by the following method.

(Basic weight of fiber sheet)
An object to be measured such as a web, a semi-finished product, or a spunlace nonwoven fabric is cut into a size of 30 cm × 30 cm and used as a sample. The sample is subjected to drying treatment in an air atmosphere at 100 ° C. or higher, and then the mass is measured. The measured mass is divided by the area of the sample to calculate the basis weight of the sample. Here, the average value of the basis weights of ten samples is taken as the basis weight of the object to be measured.
(Thickness of fiber sheet)
The thickness of the object to be measured is measured under the measurement conditions of a measurement load of 3 g / cm ² using a thickness gauge (type FS-60 DS, manufactured by Daiei Kagaku Seiki Mfg. Co., Ltd.) equipped with a 15 cm ² measuring element. Here, thickness of three places is measured about one sample for measurement, and let an average value of thickness of those three places be a thickness of a measuring object.
(Fiber density of fiber sheet (mass per unit volume: g / cm ³ ))
The weight of the fiber sheet determined by the above method is divided by the thickness of the fiber sheet determined by the above method to calculate the fiber density (mass per unit volume: g / cm ³ ) of the object to be measured.
(Fiber density of fiber sheet (book per unit volume: book / cm ³ ))
The sample is cut out to a size of 5 mm × 5 mm around the region to be measured in the measurement object. The sample is scanned 360 degrees using a fluoroscope (model SKYSCAN 1272 manufactured by Bruker Corporation). Specifically, an X-ray fluoroscopic image is taken each time the sample is rotated by 0.5 degrees, 360 X, ie, 720 X-ray fluoroscopic images are acquired, and the acquired 720 X-ray fluoroscopic images are connected. Create a 3D image together. The number of component fibers per unit volume is extracted from the 3D image for the region to be measured, and the fiber density of the region to be measured (book per unit volume: book / cm ³ ) is taken.

  In order to confirm the effect of the spunlace nonwoven fabric having the pattern according to the above embodiment, a comparative experiment is carried out on the spunlace nonwoven by the production method of the above embodiment and the spunlace nonwoven fabric by the production method different from the above embodiment. Did.

(1) Preparation of Samples (1-1) Samples of Examples 1 and 2 As the web 7, fiber density of about 3.0 × 10 ⁻³ g / cm ³ (basis weight of about 40 g / m ² , thickness of about 10 mm) A fiber laminate formed of rayon / PET / pulp fiber / rayon / PET was prepared. Next, in the manufacturing apparatus 1, water was supplied from the water supply device 2 to the web 7 at a water pressure of 0.5 MPa on the first suction drum 5. Subsequently, from the first injection nozzles 3-1 and 3-2, the injection pressure is 3.0 MPa and 6.0 MPa in the first embodiment, and the injection pressure is 3.0 MPa and 0 MPa in the second embodiment (the first injection nozzle 3 Water was supplied to the web 7 in each case -2 not used). Thereby, the concavo-convex pattern 55 is transferred to the web 7 while the fibers of the web 7 are entangled, and the semifinished product 8 in which the pattern 40 is applied to the pattern existing area 8g is formed. Thereafter, on the second suction drum 6, a semifinished product formed by omitting the water injection from the second injection nozzle 4 so as not to affect the formation of the pattern 40 in the pattern existing area 9g. 8 was used as it was as the spun lace nonwoven fabric 9 of Examples 1 and 2.

(1-2) Sample of Comparative Example 1 The same web 7 as in Example 1 is prepared, and the second suction drum 5 is not disposed in the support 54 of the first suction drum 5 in the manufacturing apparatus 1. The uneven pattern 55 was placed on the six supports. In the manufacturing apparatus 1 in such a state, water is supplied from the water supply device 2 to the web 7 at a water pressure of 0.5 MPa on the first suction drum 5, and from the first jet nozzles 3-1 and 3-2. Water was supplied to the web 7 at an injection pressure of 3.0 MPa and 6.0 MPa. As a result, the fibers of the web 7 were entangled, but a semi-finished product having no pattern was formed. Thereafter, water was injected onto the second suction drum 6 from the second injection nozzle 4 to the semifinished product at an injection pressure of 9.0 MPa. Thereby, the concavo-convex pattern 55 was transferred to the semifinished product while the fibers of the semifinished product are entangled, and the nonwoven fabric of Comparative Example 1 in which the pattern was provided in the pattern existing region was formed. Therefore, in the comparative example 1, the concavo-convex pattern was transferred by the second jet nozzle 4 on the second suction drum 6 with respect to the semifinished product in which the fibers were already entangled. That is, Comparative Example 1 can be said to be a manufacturing method different from the manufacturing method of the above embodiment.

(2) Evaluation method of the quality of the pattern 40 About the sample of the spunlace nonwoven fabric which has the pattern (a plurality of opening parts) formed using the manufacturing apparatus 1, the evaluation of the quality of the pattern of the spunlace nonwoven fabric is carried out by the following method I went there. Here, as the concavo-convex pattern, a pattern constituted by openings penetrating the non-woven fabric was used.

First, a sample is read and imaged under the same conditions with a scanner (scanner: Canon image Runner ADVANCE iR-ADVC 5255F (pixel count: 600 dpi), binarization software: SCARA, Inc. USB Digital Scale 1, 1 J). However, in scanning, black paper is placed in contact with the side of the sample opposite to the side irradiated with light. The color of each pixel is expressed in grayscale (256 tones) having a plurality of tones from black to white. In this case, the more properly the apertures are formed, the darker the image. Next, in the obtained image, the image is placed on a predetermined area (100 mm × 25 mm = 2500 mm ² ) of a predetermined area (pattern existing area) including a pattern, and the image is Perform the digitization process. Then, in the binarized image, a black portion is defined as an aperture, that is, a portion where a pattern is formed, and the ratio of the area of the black portion to a predetermined area (2500 mm ² ), ie, the area ratio is determined. The area ratio of the black part of the non-woven fabric was compared with the area ratio of the concavo-convex pattern on the support to determine the quality of the non-woven fabric. That is, (Production rate of pattern of nonwoven fabric) = (Area ratio of black part of nonwoven fabric) / (Area ratio of concavo-convex pattern on support) × 100 (%). For example, when (the quality of the pattern of the non-woven fabric) is high, the quality of the product is good, and the pattern of the non-woven fabric becomes close to the uneven pattern of the support, that is, the visibility is enhanced.

(3) Evaluation method of pattern boundaries. (Figures 3 and 4)
(3-1) Evaluation Using Maximum Value of Pixel Number of Black Tone Region A predetermined area (pattern existing region) including a pattern is represented on the gray scale image acquired in (2) above. For a region of 100 mm × 25 mm = 2500 mm ² ), a graph showing the relationship between gradation and the number of pixels is obtained. Then, determined in the graph, the black tone area _{A B,} the maximum value _{P BM1} number of pixels (peak). Further, the number of pixels P _MM1 in the central gray scale G _MM1 of the middle gray scale area is obtained. Based on these, and calculates the number of black pixels grayscale region _{A B} relative maxima _{P BM1,} the ratio RG1 number of pixels _{P MM1} in the gradation _{G MM1} of the center of the middle tone area. That is, RG1 = P _MM1 / P _BM1 is obtained. Compare that value to 2.0.
(3-2) Evaluation Using Maximum Value of the Number of Pixels of Black Tone Region and White Tone Region In the graph showing the relationship between the tone acquired in the above (3-1) and the number of pixels, black tone The maximum values P _BM1 and P _WM1 (peaks) of the pixel count and the gray levels G _BM1 and G _WM1 are determined for the area A _B and the white gradation area A _W. Further, the number of pixels P _MM1 in the gray scale G _{MM1 at} the center of the middle gray scale area is obtained. Based on these, to the sum of the maximum value of the number of black pixels tone area _{A B} and white gray scale region _{A W (P BM1 + P WM1} ), the peak of the black tone area _{A B} and white gray scale region _{A W} between the difference between the number of pixels _{P MM1} in the value _{P MM1} 'centered gradation _{G MM1} at the center tone _{G MM1} halftone area in a straight line E connecting to calculate the ratio RG2 of. That is, RG2 = (P _MM1 ′ −P _MM1 ) / (P _BM1 + P _WM1 ) is obtained. Compare that value to 0.1.

(4) Evaluation results (4-1) Results of evaluation of the finish The evaluation results of the finish of the patterns (openings) of Examples 1 and 2 and Comparative Example 1 are shown in Table 1 below. However, "black area ratio" shows the area ratio of the black part of a nonwoven fabric, and "finishing ratio" shows the quality ratio of the pattern of a nonwoven fabric calculated by said Formula. As shown in Table 1, the black area ratio was 11.1% and 9.23% for the samples of Examples 1 and 2, but 2.83% for the sample of Comparative Example 1. The performance rate was 29.6% and 24.6% for the samples of Examples 1 and 2, while it was 7.54% for the sample of Comparative Example 1. Therefore, it was found that the samples of Examples 1 and 2 have a very high black area ratio and therefore a very high yield rate as compared with the sample of Comparative Example 1. In other words, it was found that the samples of Examples 1 and 2 formed a pattern with extremely good visibility as compared with the sample of Comparative Example 1.

(4-2) Results of Evaluation Using Maximum Value of the Number of Pixels in the Black Gradation Region Evaluation results of the boundaries of the patterns (open portions) of Examples 1 and 2 and Comparative Example 1 are shown in Table 1 below. However for "RG1" black tone area _A maximum value _{P BM1} number of pixels _B, represents the ratio RG1 number of pixels _{P MM1} in the center tone _{G MM1} halftone regions, are calculated by the above formula. As shown in Table 1, the ratio RG1 is less than 2 in the samples of Examples 1 and 2 at 1.3 and 1.7, while in the sample of Comparative Example 1 it is greater than 2 at 2.1. The Therefore, it was found that the proportion of gray pixels close to black is greater than the proportion of gray pixels in the samples of Examples 1 and 2 as compared with the sample of Comparative Example 1. In other words, in the samples of Examples 1 and 2, in comparison with the sample of Comparative Example 1, the boundary between the opening (pattern) and the non-opening is clear, and a pattern with good visibility is formed. I found that
(4-3) Results of evaluation using maximum values of the number of pixels in the black gradation region and the white gradation region Evaluation results of boundaries of the patterns (open portions) in Examples 1 and 2 and Comparative Example 1 are described below. It is shown in Table 1. However "RG2" is to the sum of the maximum value of the number of pixels of the black gradation region _{A B,} and white gray scale region _{A W (P BM1 + P WM1} ), the peak of the black tone area _{A B} and white gray scale region _{A W} between the difference between the number of pixels _{P MM1} in the value _{P MM1} 'centered gradation _{G MM1} at the center tone _{G MM1} halftone area in a straight line E connecting, represents the ratio of, is calculated by the above formula. As shown in Table 1, the ratio RG2 is 0.13 in the samples of Examples 1 and 2 and 0.10 or more at 0.10, whereas the sample in Comparative Example 1 is 0.096 at 0.096. It was smaller than 1. Therefore, it was found that in the samples of Examples 1 and 2, the ratio of the near black gray and the near white gray pixels was larger than the ratio of the gray pixels, as compared with the sample of Comparative Example 1. In other words, in the samples of Examples 1 and 2, in comparison with the sample of Comparative Example 1, the boundary between the opening (pattern) and the non-opening is clear, and a pattern with good visibility is formed. I found that

9 spunlace non-woven fabric 9g pattern existing area 9h pattern non-existent area 40 pattern 40a aperture

Claims (8)

A spunlaced nonwoven fabric having a longitudinal direction, a widthwise direction and a thickness direction and having a pattern,
A pattern existing area in which the pattern exists;
And a pattern non-existing area other than the pattern existing area;
The pattern includes a plurality of openings penetrating the spunlace nonwoven fabric in the thickness direction in plan view,
In an image of the spunlace nonwoven fabric taken from above in the thickness direction,
When an area of a predetermined area in the portion indicating the pattern existing area in the image is divided into a plurality of pixels, and the color of each pixel is expressed by gray scale having a plurality of gradations from black to white, The gray scale has a black tone area on the black side, a white tone area on the white side, and an intermediate tone area between the black tone area and the white tone area. ,
In the portion showing the pattern existing area,
Each of the black tone area and the white tone area includes a tone having a peak of the maximum value of the number of pixels,
The ratio of the number of pixels in the gray level at the center of the middle gray scale area to the maximum value of the number of pixels in the black gray scale area is 2 or less.
Spunlace nonwoven fabric. In the portion showing the pattern existing area,
At the center gray scale of the middle gray scale area in a straight line connecting the peaks of the black gray scale area and the white gray scale area with respect to the sum of local maximum values of the number of pixels of the black gray scale area and the white gray scale area. The ratio between the value and the difference between the number of pixels in the central gray level is 0.1 or more.
The spunlace nonwoven fabric according to claim 1. The spunlace nonwoven comprises pulp fibers,
Each of the plurality of openings surrounds the through hole of the opening with a predetermined width in the in-plane direction parallel to the longitudinal direction and the width direction, and has a contour region extending in the thickness direction.
The fiber density of pulp fibers in the contoured area is higher than the fiber density of pulp fibers in the non-patterned area,
The spunlace nonwoven fabric according to claim 1 or 2. A first outer layer, a second outer layer, and an intermediate layer located between the first outer layer and the second outer layer and containing the pulp fibers;
The spunlace nonwoven fabric according to claim 3. The intermediate layer has a higher fiber density than the first outer layer and the second outer layer,
The spunlace nonwoven fabric according to claim 4. The half tone region includes a tone having a minimum value of the number of pixels,
The minimum value is smaller than the maximum value of the number of pixels of the black tone area and the white tone area,
The spunlace nonwoven fabric according to any one of claims 1 to 5. The plurality of openings include at least two types of openings having different shapes from each other,
The shape of each of the at least two types of openings is selected from a circle, an ellipse, a polygon, a straight line, a curve, or a combination thereof.
The spunlace nonwoven fabric according to any one of claims 1 to 6. The pattern non-existing area is
A central pattern non-existing region located in the widthwise central portion of the spunlace nonwoven fabric and extending in the longitudinal direction;
And at the widthwise end of the spunlaced nonwoven fabric, the longitudinally extending end pattern non-existing region;
The pattern existing area is
It is located between the central pattern non-existence area and the end pattern non-existence area, and includes the longitudinally extending end pattern presence area,
The spunlace nonwoven fabric according to any one of claims 1 to 7.

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