JP6607893B2 - Non-woven - Google Patents

Description

  The present invention relates to a nonwoven fabric.

  In absorbent articles such as sanitary napkins and diapers, there are known techniques for imparting various functions to a surface material (also referred to as a surface sheet) that touches the skin.

  For example, the absorbent article described in Patent Document 1 has a top sheet including a ridge portion and a bottom portion between the ridge portions for the purpose of preventing skin sticking. The top of the ridge has a plurality of recesses, and a plurality of openings are arranged in the wall of the ridge. When the top sheet is made of a resin film, the body fluid absorbed by the absorbent body can be seen through the opening when the absorbent article is viewed obliquely.

JP 2013-78362 A

In the absorbent article, the user can feel the absorbency, and in order to be able to use it with peace of mind, the excretion after absorption (menstrual blood, urine, loose stool, etc.) cannot be seen from the skin side surface (highly concealed) ) Is one of the important conditions. On the other hand, it is possible to visually confirm that excrement is drawn into the back from the skin side surface of the absorbent article and absorbed so that the user can realize a firm absorbency (low concealment and visibility) It is desirable to have. In particular, when the difference in concealment is caused by changing the viewpoint, the user can effectively feel the absorbent power of the absorbent article in the following usage scenes. That is, when the absorbent article after use is peeled off, it is possible to first realize a safe absorption force that is free from leakage when viewed from the front. It can then be lifted to recall the impression of being firmly absorbed from the surface. It is desired to realize such performance in a soft nonwoven fabric that is preferably used for the surface sheet.
However, the concealment of colored objects such as dirt and the visibility that can be confirmed that the colored objects are firmly drawn into the back are contradictory properties, and it is not easy to achieve both of them firmly in a nonwoven fabric. There wasn't. Providing an opening like the resin film of Patent Document 1 has a problem in terms of strength in a non-woven fabric made of an aggregate of fibers. Moreover, when an opening is provided in the nonwoven fabric, there is a problem that liquid return may occur due to the hydrophilicity of the nonwoven fabric. Therefore, in a nonwoven fabric, it is difficult to give sufficient visibility with respect to excrement by an opening part.

  The present invention has a concealing property for a colored object such as excrement absorbed in an absorbent article, and a visibility for confirming that the colored object is pulled into the back, and both properties are angles that an observer sees. The present invention relates to a non-woven fabric that can be expressed by changing.

The present invention comprises an area where the concealability for a colored object when viewed from an oblique direction is lower than the concealment property for a colored object when viewed from above in the vertical direction with respect to one surface side of the nonwoven fabric. Provide a nonwoven fabric.
Further, the present invention has an uneven surface provided with a convex top portion, a concave bottom portion, and a wall portion connecting the convex top portion and the concave bottom portion on one surface side of the nonwoven fabric, and the wall portion is the one surface or A nonwoven fabric that extends in a direction perpendicular to the surface on the opposite side and has a basis weight of the wall portion smaller than a basis weight of the convex top portion and the concave bottom portion is provided.

  The nonwoven fabric of the present invention has a concealment property for colored objects such as excrement absorbed in the absorbent article and visibility for confirming that the colored objects are drawn in the back, and both properties are observed by the observer. It can be expressed by changing the viewing angle.

It is the perspective view which showed typically the state which mounted one preferable embodiment of the nonwoven fabric which concerns on this invention with a colored thing on the horizontal plane. It is the block diagram which showed the outline of the measuring method of opacity. It is the fragmentary sectional view which showed typically other preferable one Embodiment of the nonwoven fabric which concerns on this invention. It is the fragmentary sectional view which showed typically other preferable one Embodiment of the nonwoven fabric which concerns on this invention. It is the fragmentary sectional view which showed typically other preferable one Embodiment of the nonwoven fabric which concerns on this invention. It is the fragmentary sectional perspective view which showed typically other preferable one Embodiment of the nonwoven fabric which concerns on this invention. It is the II-II sectional view taken on the line of the nonwoven fabric shown in FIG. It is the III-III sectional view taken on the line of the nonwoven fabric shown in FIG. (A) is a partially enlarged sectional view showing the angle of the wall in the longitudinal section of FIG. 7, and (B) shows the angle of the wall when the surface of the wall is an uneven surface. (A) It is a partially expanded sectional view corresponding to a figure, (C) A figure is a partially expanded sectional view corresponding to the said (A) figure which shows the angle of the wall part when the wall part is opened. It is. It is the front view which showed typically the fiber orientation of the wall part of the nonwoven fabric of this embodiment. It is a related figure of DTG / fiber input amount and temperature in the top part, bottom part, and wall part of the nonwoven fabric of this embodiment. It is sectional drawing which showed typically an example of the preferable manufacturing method of the nonwoven fabric of this embodiment, (A) arrange | positions a fiber web on a support body male material, and supports a support body material from the said fiber web on a support body male material. (B) is a cross-sectional view schematically showing a step of shaping the fiber web by striking the first hot air from above the support female material, (C) is a cross-sectional view schematically showing the process of removing the support female material and blowing the second hot air from above the shaped fiber web to fuse the fibers together. BRIEF DESCRIPTION OF THE DRAWINGS It is drawing which showed the preferable example of the sanitary napkin which applied the nonwoven fabric of this invention to the surface sheet, (A) The figure is a partial notch schematic perspective view, (B) The figure was shown in (A) figure It is an expansion partial cross-section perspective view in A section.

  A preferred embodiment of the nonwoven fabric according to the present invention will be described below with reference to the drawings. However, the present invention is not construed as being limited thereby.

  As shown in FIG. 1, the nonwoven fabric 10 of this embodiment has a front and back surface. In the present embodiment, the front and back surfaces will be described as one surface (first surface) 10SA and the other surface (second surface) 10SB opposite to the one surface 10SA. Further, the thickness direction of the nonwoven fabric 10 is referred to as a Z direction, the first surface 10SA side is also referred to as a first surface side Z1, and the second surface 10SA side is also referred to as a second surface side Z2. In this embodiment, unless otherwise specified, one surface (first surface) 10SA is shown as a surface (observation surface) for visual observation, but the nonwoven fabric of the present invention is not limited to this, and the other surface ( (2nd surface) It is good also as a surface (observation surface) which observes 10SB.

  The non-woven fabric 10 has a colored object 300 when viewed from the upper side in the oblique direction S with respect to the one surface 10SA side, rather than a concealing property with respect to the colored object 300 when viewed from the upper side in the vertical direction V with respect to the one surface 10SA side. It has a region where the concealment property for the is low. Here, the “colored material” means a colored material that is transferred from the one surface 10SA side of the nonwoven fabric to the other surface 10SB side. For example, it is a colored fluid such as menstrual blood, urine, and loose stool. “Colored” means both chromatic and achromatic colors.

  The angles of the “vertical direction V” and the “oblique direction S” are basically determined based on a non-woven fabric surface that is visually observed (hereinafter also referred to as a reference surface). In the present embodiment, the determination is made based on one surface 10SA of the nonwoven fabric 10. When the surface 10SA to be viewed is not flat but an uneven surface, the nonwoven fabric surface on the side in contact with the plane 10P in the state where the nonwoven fabric 10 is placed on the horizontal plane 10P with the other surface 10SB down, that is, The other surface 10SB can also be determined as a reference surface. In this case, the plane 10P and the other surface 10SB of the nonwoven fabric surface are substantially the same plane. Therefore, when the other surface 10SB is an uneven surface, the plane 10P may be used as the reference surface. In the present embodiment, as shown in FIG. 1, in a state where the nonwoven fabric 10 is placed on the horizontal plane 10P with the other surface 10SB down, the plane 10P is made of the nonwoven fabric reference surface 10SS (hereinafter simply referred to as the reference surface 10SS). It is also called.)

The “vertical direction V” is an angle α that is greater than 80 ° and less than 100 ° with respect to the above-described reference surface 10SS, and refers to a direction away from one surface 10SA. The angle α with respect to the reference surface 10SS is preferably 85 ° or more and 95 ° or less, more preferably 89 ° or more and 91 ° or less, and particularly preferably 90 °. “Visually viewing from above the vertical direction V” means viewing from the position away from the one surface 10SA side at the angle α to the one surface 10SA along the vertical direction V (hereinafter, referred to as “viewing from above”). This viewing position is called the vertical viewpoint.)
The “oblique direction S” is an angle β of 30 ° or more and 80 ° or less with respect to the reference surface 10SS described above, and is a direction away from one surface 10SA. The angle β with respect to the reference surface 10SS is preferably 30 ° or greater and 70 ° or less, more preferably 50 ° or greater and 65 ° or less, and even more preferably 50 ° or greater and 60 ° or less. “Visible from above the oblique direction S” means to visually observe the one surface 10SA along the oblique direction S from a position away from the one surface 10SA side at an angle β (hereinafter, referred to as “behind”). This viewing position is called an oblique viewpoint.)
“Concealment with respect to colored objects when viewed from above in an oblique direction is reduced” means that at least one point in the above-described oblique direction S (for example, 30 ° or more and 80 ° or less with respect to the reference surface 10SS) is visible. This means that the concealment of colored objects is reduced.

  The “hiding property” indicates how difficult it is to recognize the presence of the colored object 300 below the one surface 10SA when the nonwoven fabric 10 is viewed with the one surface 10SA facing up. This “concealment” is determined by the color difference through the fiber layer of the nonwoven fabric 10 between the vertical viewpoint and the oblique viewpoint. From the viewpoint of making the difference in the degree of concealment with respect to the colored object 300 clearer, the nonwoven fabric 10 is preferably composed entirely of a monochromatic fiber layer, and more preferably composed of a white fiber layer. In this embodiment, it demonstrates below that the nonwoven fabric 10 is comprised by the white fiber layer.

  This color difference is obtained by the difference in the degree of light transmission from the fiber layer of the nonwoven fabric 10 toward the other surface 10SB side from the one surface 10SA side. In other words, a lower “hiding property” at an oblique viewpoint than at a vertical viewpoint means that the degree of light transmission through the fiber layer is higher at the oblique viewpoint. Although the nonwoven fabric 10 may have an opening, it is preferable that the nonwoven fabric 10 does not have an opening. This contributes to the performance related to the “hiding property” of the nonwoven fabric 10. That is, it is preferable that the nonwoven fabric 10 does not have an opening part from a viewpoint by which the return of the colored object 300 which moved to the nonwoven fabric 10 downward (2nd surface side Z2) is suppressed. Thereby, it can suppress that the concealability (the concealment property with respect to the stain | pollution | contamination by excrement) with respect to the colored object 300 required for the nonwoven fabric 10 reduces by the return of the colored object 300. FIG. Moreover, the strength fall of the nonwoven fabric 10 by an opening part can be avoided. By maintaining the strength of the nonwoven fabric in this way, both the concealment with respect to the colored object 300 and the visibility capable of recognizing that the colored object 300 is pulled into the back are compatible with the use time of the nonwoven fabric. It will be sustainable.

(Concealment measurement method)
The hiding property indicated by the color difference is measured by the following method because the hiding state is white (reference value L93: a128: b128), and the hiding property becomes higher when closer to white (FIG. 2). reference).
(1) The red standard plate (hereinafter also referred to as a standard plate) manufactured by Nippon Denshoku Industries Co., Ltd. on the side facing the measurement surface (one surface 10SA) of the nonwoven fabric 10 upward and the surface facing the lower side (the other surface 10SB). .) 210 is put.
(2) The measurement position M1 is determined with respect to the measurement surface of the nonwoven fabric 10, and the vertical direction V (angle α) at the measurement position M1 is determined using an angle meter. The standard plate 210 over the nonwoven fabric 10 is imaged together with the image correction color chart 230 from the position 20 cm above the vertical direction V of the measurement position M1 using the imaging device 220 (hereinafter, this captured image is also referred to as a vertical viewpoint image). ). The measurement surface (one surface 10SA) including the measurement position M1 is the uppermost surface of the nonwoven fabric 10 and is set in parallel with the nonwoven fabric reference surface 10SS.
(3) At the measurement position M1 on the measurement surface of the nonwoven fabric 10, an oblique direction S (angle β) is determined using an angle meter. The standard plate 210 over the nonwoven fabric 10 is imaged together with the image correction color chart 230 from the position 20 cm above the diagonal direction S of the measurement position M1 using the imaging device 220 (hereinafter, this captured image is also referred to as an oblique viewpoint image). ).
(4) Image processing for uniform correction of the color information level is performed using an image correction color chart in which an image captured from above in the vertical direction and an image captured from above in the oblique direction are copied to the image. Next, based on the image processed image data, a color difference ΔE ^* _ab from the reference value (white) is obtained based on the following formula (A1).
ΔE ^* _ab = [(ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² ] ^1/2 (A1)
(In the formula, L ^* indicates lightness, a ^* and b ^* indicate chromaticity. ΔL ^* , Δa ^*, and Δb ^* are white reference values and images taken from above in the vertical direction of the nonwoven fabric 10, nonwoven fabric. 10 shows the difference from the image taken from the upper side of 10 diagonal directions.)
ΔE ^* _{ab of} the image captured from the upper part of the nonwoven fabric 10 in the vertical direction represents the concealment rate E _α for the colored object 300 when viewed from the upper part of the vertical direction. ΔE ^* _{ab of} the image captured from the upper side of the nonwoven fabric 10 represents the concealment rate E _β with respect to the colored object 300 when viewed from the upper side of the diagonal direction. The hiding ratios E _α and E _β are both closer to white as the value is lower, indicating that the hiding property is higher. Here, when the difference in concealment ratio is less than 0.5, it becomes an identification limit based on JIS L 0804 and JIS L 0805, in which a person cannot judge the color difference. That is, a human can recognize a difference in concealment rate when there is a difference of 0.5 or more. Difference in contrast ratio E _beta for contrast ratio E _alpha a _(E β -E _α) and the difference in contrast ratio.

More specifically, the above measuring method is performed as follows.
The angle α in the vertical direction V shown in (2) above is set to 90 °, and an image at the vertical viewpoint is taken together with the image correction color chart 230. In addition, the angle β in the oblique direction S shown in (3) above is changed to a predetermined interval in the range of 30 ° to 80 °, and images of respective oblique viewpoints are taken. For example, an image of an oblique viewpoint is imaged together with the image correction color chart 230 at a position where the optical axis L1 of the imaging device 220 is tilted by 10 ° from 30 ° to 80 ° with the measurement position M1 as a fulcrum from the vertical direction V. To do. The 100 ° position is substantially the same as the 80 ° position. As the angle meter, for example, Bruce Land Dial type product number 78544 (trade name) manufactured by Shinwa Measurement Co., Ltd. can be used. In the measurement methods (2) and (3), the imaging position is a distance of 20 cm from the surface of the nonwoven fabric to the lens outermost surface of the imaging apparatus, and the optical axis of the lens of the imaging apparatus faces the imaging position M1 from the imaging position. To be.
As the imaging device 220, a digital camera PowerShot S120 (trade name) manufactured by Canon Inc. can be used. For example, CASMATCH (trade name: manufactured by Bear Medic Co., Ltd.) can be used for the color chart 230 for image correction. In addition, it is preferable to use a daylight white light bulb that is a natural white light close to sunlight with a color temperature of about 5000 K for illumination at the time of photographing, and illuminate from the direction 200 cm vertically above the imaging region. It is preferable not to use a camera flash so that light other than the light source does not enter during photographing.

For the image processing shown in (4) above, an image correction color chart is used. And according to Shigeru Kano (1999) “Utilization and color processing of digital images at the forefront of medical care: From the field of otolaryngology”, “The first“ color ”symposium of digital medical images: Panel discussion part 2” To correct. The image to be processed is opened with image processing software product name Adobe Photoshop CSS version 12.0 (manufactured by Adobe), and the channel is set to the RGB channel. Then, the color information level is corrected to white (R [228], G [228], B [228]) in the white area of CASMATCH by the color picker. Similarly, the color information level is corrected so that the gray area of CASMATCH is gray (R [114], G [114], B [114]), and the black area of CASMATCH is black (R [35], G [35]). , B [35]), the color information level is corrected.
Next, for the vertical viewpoint image and the oblique viewpoint image, the corrected image is set in the _Lab channel, an area corresponding to the red area of the standard plate 210 of the image is selected, and the histogram is confirmed. Then, three-dimensional orthogonal coordinates (L ^* , a ^* , b ^* ) of a CIE 1976 L ^* a ^* b ^* color space (CIELAB color space), which will be described later, are obtained.

The CIE1976 L ^* a ^* b ^* color space (CIELAB color space) indicates a uniform perceptual color space by three-dimensional orthogonal coordinates (L ^* , a ^* , b ^* ). L ^* , a ^* , and b ^* are defined by the following mathematical formulas (B1), (B2), and (B3) according to JIS Z 8720: 2012 colorimetric standard illuminant (standard light) and standard light source.
L ^* = 116 × (Y / Y _n ) ^1/3 −16 (B1)
a ^* = 500 × [(X / X _n ) ¹ / 3− (Y / Y _n ) ^1/3 ] (B2)
b ^* = 200 × [(Y / Y _n ) ¹ / ^3- (Z / Z _n ) ^1/3 ] (B3)
X _n , Y _n and Z _n are tristimulus values of the illumination light source.
In case of standard light C (2-degree field of view XYZ system)
Y _n = 100, X _n = 98.072, Z _n = 118.225
For standard light _{D 65} (2 degree visual field XYZ system)
Y _n = 100, X _n = 95.045, Z _n = 108.892
However, this is applied when X / X _n ≧ 0.008856, Y / Y _n ≧ 0.008856, and Z / Z _n ≧ 0.008856.

Next, based on the calculated three-dimensional orthogonal coordinates (L ^* , a ^* , b ^* ), the color difference between the vertical viewpoint image or the oblique viewpoint image and the white reference value is expressed by the above-described formula (A1). ).

When the concealment rate E _β is larger than the concealment rate E _{α and} the difference in the concealment rate (E _β -E _α ) is 0.5 or more, the concealment for the colored object 300 when viewed from above in the vertical direction V. It is determined that the concealment property with respect to the colored object 300 when viewed from above the oblique direction S is lower than the property. The difference in the concealment rate is preferably 1 or more, more preferably 1.5 or more.
Moreover, when the difference in the concealment ratio is −0.5 or less, the concealability for the colored object 300 when viewed from the oblique direction S is higher than the concealability for the colored object 300 when viewed from above the vertical direction V. It is judged to be higher. Further, when the difference in the concealment ratio is smaller than 0.5 and larger than −0.5, the concealability with respect to the colored object 300 when viewed from above the vertical direction V and the colored object when viewed from above the oblique direction S. It is determined that the concealment property for 300 is equivalent.

  Next, in the nonwoven fabric 10, a preferable aspect in which the hiding property at the oblique viewpoint is lower than the hiding property at the vertical viewpoint will be described.

  The nonwoven fabric 10 may have various shapes as long as it has a concealing property that varies depending on the viewing angle. For example, one surface 10SA side may be a flat surface or an uneven surface. Below, the nonwoven fabric 10A-10D is mentioned and demonstrated as a preferable aspect of the nonwoven fabric 10. FIG. However, the nonwoven fabric of the present invention is not limited to these embodiments.

FIG. 3 shows a preferred embodiment of nonwoven fabric 10 (10A). In the nonwoven fabric 10A, one surface 10SA side and the other surface side SB are flat.
The nonwoven fabric 10A is composed of three fiber layers in the thickness direction. A semi-dal layer 21 made of semi-dal fibers is sandwiched between one side 10SA side and the other surface 10SB side, and a semi-dal layer 22 and a full-dal layer 23 made of full-dal fibers are alternately arranged in the plane direction. In the present embodiment, a layer composed of the semidal layer 22 and the fulldal layer 23 on the one surface 10 SA side is referred to as a first surface layer 24. A layer composed of the semi-dal layer 22 and the full-dal layer 23 on the other surface 10B side is referred to as a second surface layer 25. The intermediate semi-dal layer 21 is also referred to as the intermediate layer 21. The full dull layer 23 made of full dull fibers has a light transmittance lower than that of the semi dull layers 21 and 22 made of semi dull fibers, and has high concealment with respect to colored substances.

  The “semi-dal” is a fiber having a little gloss and the color changing material per unit mass of the fiber is less than 1% by mass, or a fiber satisfying any one condition. “Fludall” is a fiber that has no gloss and is a fiber in which the mass of the color tone changing material per unit mass of the fiber is 1% by mass or more, or a fiber that satisfies one of the conditions. The gloss is measured by JIS L 1013: 2010 chemical fiber filament yarn test method, 8.24 glossiness. The determination method of “semi-dull” or “full-dull” based on the content of the color change material is JIS L 1013: 2010 chemical fiber filament yarn test method and 8.25 ash content measurement method. The ash content per fiber unit mass can be obtained by this measurement method, and the ash content per fiber unit mass can be determined as the content of the color tone changing material.

As shown in FIG. 3, the nonwoven fabric 10A is arranged so that the same kind of layers do not overlap on the one surface 10SA side and the other surface 10SB side. That is, a fullal layer 23 is disposed at a position corresponding to the second surface layer 25 with respect to the semi-dal layer 22 of the first surface layer 24, and the second surface layer 25 of the first surface layer 24 with respect to the fullal layer 23 of the first surface layer 24. A semi-dal layer 22 is disposed at the corresponding position. Accordingly, when the nonwoven fabric 10A is viewed from the upper side in the vertical direction from the one surface 10SA side (or the other surface 10SB side), the non-woven fabric 10A is perpendicular to the fuldal layer 23 of the first surface layer 24 and the fludal layer 23 of the second surface layer 25. The light transmission in the direction is blocked, and the concealment is high.
On the other hand, when viewed from obliquely above, light is easily transmitted through the semi-dal layer 22 of the first surface layer 24, the intermediate semi-dal layer 21, and the semi-dal layer 22 of the second surface layer 25. In this oblique direction, concealment is made lower than in the vertical direction.
That is, in the laminated region of the first surface layer 24, the intermediate layer 21, and the second surface layer 25, rather than the concealment with respect to a colored object (see FIG. 1) when viewed from the vertical viewpoint with respect to the one surface 10SA side, The concealment property for colored objects when viewed from an oblique viewpoint is lowered. Thereby, in 10 A of nonwoven fabrics, the concealability with respect to a colored object and the visibility which can recognize that the colored object is drawn in back are compatible.

FIG. 4 shows the nonwoven fabric 10 (10B) of another preferred embodiment. The nonwoven fabric 10B is a nonwoven fabric in which the one surface 10SA side and the other surface side SB are made uneven.
The nonwoven fabric 10B is a mode in which the first surface layer 24 and the second surface layer 25 do not have the semidal layer 22 in the laminated structure of the nonwoven fabric 10A described above. That is, the first surface layer 24 and the second surface layer 25 in which an uneven surface is formed by disposing the full dull layer 23 on the one surface 10SA side and the other surface 10SB side across the semi-dal layer 21 which is an intermediate layer. Have. In each of the first surface layer 24 and the second surface layer 25, a concave portion 26 in which no fiber is disposed is formed between the fullal layers 23. That is, the full dull layer 23 becomes the convex portion 23, and the convex portion 23 and the concave portion 26 are alternately arranged. Thereby, both surfaces 10SA and 10SB of the nonwoven fabric 10B are uneven surfaces. The convex portion 23 has a convex top portion 23A made of a fiber of a full-dal layer, and the concave portion 26 has a concave bottom portion 26A made of a fiber of a semi-dal layer. Moreover, the convex part 23 has the wall part 3 which consists of a fiber of a full dull layer which connects the convex top part 23A and the concave bottom part 26A.

In the nonwoven fabric 10 </ b> B, the fuller layer 21 as an intermediate layer is exposed at the bottom of the recess 26. In addition, the first surface layer 24 and the second surface layer 25 are arranged such that the full-dal layers 23 do not overlap each other. Accordingly, the light transmission in the vertical direction is blocked by the fullal layer 23 of the first surface layer 24 and the fullal layer 23 of the second surface layer 25. Therefore, the concealability when viewed from a vertical viewpoint is high. On the other hand, when viewed from an oblique viewpoint, light is easily transmitted through the intermediate semidal layer 21 exposed at the positions of the recesses 26 of the first surface layer 24 and the recesses of the second surface layer 25. In this oblique direction, concealment is made lower than in the vertical direction.
That is, in the laminated region of the first surface layer 24, the intermediate layer 21, and the second surface layer 25, rather than the concealment with respect to a colored object (see FIG. 1) when viewed from the vertical viewpoint with respect to the one surface 10SA side, The concealment property for colored objects when viewed from an oblique viewpoint is lowered. Thereby, in the nonwoven fabric 10B, the concealment property with respect to the colored object and the visibility capable of recognizing that the colored object is drawn into the back are compatible.

  In nonwoven fabric 10A (FIG. 3) and 10B (FIG. 4), the lamination | stacking area | region of the 1st surface layer 24, the intermediate | middle layer 21, and the 2nd surface layer 25 may be in the nonwoven fabric 10A whole, or even if it exists in part. Good. When it exists in a part, it is preferable that the said lamination | stacking area | region exists in the liquid receiving area which receives a liquid directly at least. For example, in an absorbent article, it is preferable that it exists in the area | region corresponding to a wearer's excretion part.

  In addition, in the first surface layer 24 and the second surface layer 25 of the nonwoven fabric 10A, the direction of the alternate arrangement of the semidal layer 22 and the fullal layer 23 can be appropriately set. For example, the alternate arrangement may be arranged along the longitudinal direction of the nonwoven fabric (machine flow direction (MD)). You may distribute | arrange along the width direction (direction (CD; Cross Direction) orthogonal to the machine flow direction at the time of manufacture) orthogonal to a longitudinal direction. Moreover, the extended length of each of the semi-dal layer 22 and the full-dal layer 23 may extend over the entire length in the width direction or the longitudinal direction of the nonwoven fabric, or may be arranged in a part shorter than the entire length. When the extension length of each of the semidal layer 22 and the fulldal layer 23 is shortened, the semidal layer 22 and the fulldal layer 23 may be alternately arranged along the extending direction. That is, the semi-dal layer 22 and the full-dal layer 23 may be alternately arranged in a lattice pattern along both the longitudinal direction and the width direction of the nonwoven fabric. Moreover, it may be regularly arranged along both the longitudinal direction and the width direction, the arrangement cycle may change along one or both of the longitudinal direction and the width direction, and it may be arranged irregularly. May be. You may arrange | position so that the pattern made by the semidal layer 22 and the full dull layer 23 can be seen on the nonwoven fabric 10A surface. Thereby, in 10 A of nonwoven fabrics, a design can be visually recognized.

  In the first surface layer 24 and the second surface layer 25 of the nonwoven fabric 10B, the direction of the alternate arrangement of the full-dal layer (convex portion) 23 and the concave portion 26 can be set as appropriate as in the nonwoven fabric 10A. The extended lengths of the full layer (convex portion) 23 and the concave portion 26 can also be set as appropriate, similarly to the nonwoven fabric 10A. The convex portions 23 and the concave portions 26 may be alternately arranged in a lattice pattern along both the longitudinal direction and the width direction of the nonwoven fabric. Moreover, it may be regularly arranged along both the longitudinal direction and the width direction, the arrangement period may change along one or both of the longitudinal direction and the width direction, and the arrangement may be irregular. May be. You may arrange | position so that the pattern made by the convex part 22 and the recessed part 26 can be seen on the nonwoven fabric 10B surface. Thereby, the design can be visually recognized in the nonwoven fabric 10B.

One embodiment of the nonwoven fabric 10A (FIG. 3) can be manufactured as follows, but the manufacturing method is not limited to this.
For the nonwoven fabric 10A, first, two types of webs or nonwoven fabrics made of semi-dal fibers (hereinafter referred to as first semi-dal material and second semi-dal material) and webs or nonwoven fabrics made of full-dal fibers (hereinafter referred to as full-dal materials) are used. prepare.
Next, the first semi-dal material and the full-dal material are slit in the MD direction. On the surface of the second semi-dal material, the slit first semi-dal material and the slit full-dal material are alternately arranged and laminated. The slits of the first semidal material and the fulldal material are alternately arranged and laminated on the back surface of the first semidal material facing the front surface. In that case, it laminates | stacks alternately so that it may become the order laminated | stacked on the said surface, and it joins suitably, and manufactures 10 A of nonwoven fabrics.
As a result, as shown in FIG. 3, the semi-dal layer 22 made of the first semi-dal material and the fuldal layer 23 made of the ful-dal material are arranged opposite to each other with the intermediate layer (semi-dal layer) 21 made of the second semi-dal material sandwiched therebetween. Is done.
As another method, an uneven semi-dal material having an uneven surface is formed using semi-dal fibers by various methods usually used for forming a nonwoven fabric. Then, the nonwoven fabric 10A can be manufactured by laminating a full dull material on the concave portion of the concave-convex semi-dal material and joining them appropriately.

One embodiment of the nonwoven fabric 10B (FIG. 4) can be manufactured as follows, but the manufacturing method is not limited to this.
As the nonwoven fabric 10B, a web or nonwoven fabric (hereinafter referred to as a semidal material) made of a semidal fiber and a web or nonwoven fabric (hereinafter referred to as a fulldal material) made of a fulldal fiber are prepared.
Slit full dull material in MD direction. The nonwoven fabric 10B is manufactured by alternately arranging and stacking slit fuldal materials on the front surface of the semi-dal material and the back surface facing the semi-dal material, and joining them appropriately.
As a result, as shown in FIG. 4, in each of the first surface layer 24 and the second surface layer 25 located on both sides of the intermediate layer (semidal layer) 21 made of a semidal material, a convex portion (a fullal layer) made of a fullal material. ) 23 and the concave portions 26 where the full-dull material between the convex portions is not disposed are alternately arranged.
Further, the uneven surface in the nonwoven fabric 10B can be further formed to have unevenness by various methods usually used for forming the nonwoven fabric.

FIG. 5 shows yet another preferred embodiment of a nonwoven fabric 10 (10C). The nonwoven fabric 10C has one surface 10SA side as an uneven surface and the other surface 10SB side as a flat surface.
The uneven surface of the nonwoven fabric 10 </ b> C is formed by alternately arranging convex portions 28 and concave portions 29. The uneven surface is further provided with a wall portion 3 that connects the top portion 28A of the convex portion 28 (hereinafter referred to as the convex top portion 28A) and the bottom portion 29A of the concave portion 29 (hereinafter referred to as the concave bottom portion 29A). The convex top portion 28A, the concave bottom portion 29A, and the wall portion 3 are exposed to the one surface 10SA side to form the uneven surface.
In the nonwoven fabric 10C, the color tone changing material 6 is disposed on the convex top portion 28A and the concave bottom portion 29A. On the other hand, in the wall 3, the content of the color tone changing material 6 is less than that of the convex top 28A and the concave bottom 29A. In FIG. 5, the wall portion 3 is shown as an aspect in which the color tone changing material 6 is not contained.
The measuring method of content of the color change material 6 can be calculated | required by the measuring method of JIS L 1013: 2010 chemical fiber filament yarn, and the measuring method of 8.25 ash. Alternatively, when the color change material 6 is titanium oxide, it is obtained by various measurement methods such as JIS L 1013: 2010 chemical fiber filament yarn test method, 8.26 titanium oxide measurement method, thermal catalyst activity amount estimation method, and the like. be able to. The estimation method based on the thermocatalytic activity amount can be measured from the thermocatalytic activity amount of the color tone changing material by the differential thermal-thermogravimetric simultaneous measurement (TG-DTA) method. And, mass change rate: DTG / fiber input [% / min] obtained by dividing DTG (Derivative Thermogrammetry) [μg / min] by fiber input corresponds to the content [wt%] of the color change material in the fiber. And can be used as an estimated value. This differential thermal-thermogravimetric simultaneous measurement (TG-DTA) is performed in accordance with JIS K0129.

The “color tone changing material” refers to a material having a function of lowering the transmittance of light incident on a non-woven fabric to scatter. Examples thereof include inorganic powders and organic powders having a refractive index different from that of the constituent fibers of the nonwoven fabric.
Examples of the inorganic powder include titanium oxide, porous silicon oxide (silica), porous silica, aluminum oxide (alumina), lime, and clay mineral. Examples of the clay mineral include smectite, montmorillonite, bentonite, kaolinite, sericite, illite, glowconite, chlorite, zeolite, talc, and mizukanite.
Examples of the organic powder include polyethylene powder, polyester powder, polypropylene powder, polyacryl powder, polyacrylate powder, cellulose powder, viscose powder, silk powder, silicone compound powder, fluorine compound powder, and the like. Moreover, what colored these organic powders with the pigment | dye is mentioned.

In the nonwoven fabric 10C, the color tone changing material 6 is disposed on the surfaces of the convex top portion 28A and the concave bottom portion 29A.
Such an arrangement can be performed by a coating process on the surfaces of the convex top portion 28A and the concave bottom portion 29A. The coating treatment can be performed by a commonly used method. For example, printing coating processes such as letterpress printing, intaglio printing, lithographic printing, and stencil printing, spray coating processes, inkjet coating processes, and the like can be given. As a method of reducing the content of the color tone changing material in the wall 3 compared to the convex top portion 28A and the concave bottom portion 29A, the phases of the concave and convex portions of the convex top portion 28A and the concave bottom portion 29A are matched and applied to the convex top portion 28A and the concave bottom portion 29A The method of processing is mentioned. Further, there are a method of applying a paint containing a large amount of color tone changing material to the convex top portion 28A and the concave bottom portion 29A using electrostatic induction, a method of applying a coating treatment by masking the wall portion 3, and the like.

In the nonwoven fabric 10C, since the color tone changing material 6 is disposed on the surfaces of the convex top portion 28A and the concave bottom portion 29A, transmission of light in the direction perpendicular to the one surface 10SA is blocked. Therefore, the concealability when viewed from above in the vertical direction is high. On the other hand, when viewed from obliquely above, the light transmittance in the wall portion 3 is better than that of the convex top portion 28A and the concave bottom portion 29A. In this oblique direction, concealment is made lower than in the vertical direction.
That is, in the region of the concavo-convex surface, when concealed with respect to a colored object (see FIG. 1) when viewed from above in the vertical direction with respect to the convex top portion 28A and the concave bottom portion 29A, Concealment of colored objects is reduced. Thereby, in 10 C of nonwoven fabrics, the concealability with respect to a colored object and the visibility which can recognize that the colored object is drawn in back are compatible.

  The difference (C1−C2) between the content (C1) of the color tone changing material 6 in each of the convex top portion 28A and the concave bottom portion 29A and the content (C2) of the color tone changing material 6 in the wall portion 3 may be in the following range. preferable. From the viewpoint of effectively expressing the concealability and visibility, the difference (C1-C2) is preferably 0.1% by mass or more, and more preferably 0.3% by mass or more. The difference (C1-C2) is preferably 10% by mass or less, more preferably 5% by mass or less, and still more preferably 3% by mass or less from the viewpoint of suppressing color unevenness of the entire nonwoven fabric.

  The content (C1) of the color tone changing material 6 in each of the convex top portion 28A and the concave bottom portion 29A is more than 0 (zero) mass% and 0.15 mass% from the viewpoint of realizing high “hiddenness” in the vertical viewpoint. The above is more preferable, and 3% by mass or more is more preferable. The content (C1) is preferably 20% by mass or less, more preferably 10% by mass or less, and more preferably 5% by mass from the viewpoint of maintaining good fiber moldability, fiber processability, nonwoven fabric moldability, and nonwoven fabric processability. The following is more preferable.

  The content (C2) of the color tone changing material 6 in the wall 3 is preferably 10% by mass or less, more preferably 5% by mass or less, and more preferably 3% by mass from the viewpoint of sufficiently reducing the “concealment” at an oblique viewpoint. Further preferred. Further, the content (C2) is preferably 0 (zero)% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.15% by mass or more from the viewpoint of enhancing the concealability of the entire nonwoven fabric.

  In the nonwoven fabric 10C, the arrangement direction and the arrangement region of the concavo-convex surface can be appropriately set similarly to the nonwoven fabric 10B. In addition, the uneven surface of the nonwoven fabric 10C can be formed by various methods that are usually used for shaping the nonwoven fabric.

  Next, another preferred embodiment of the nonwoven fabric 10 will be described with reference to FIGS.

FIG. 6 shows a nonwoven fabric 10 (10D) having an uneven surface.
The nonwoven fabric 10D has an uneven surface 8 on the first surface side Z1, which is one surface side, and an uneven surface 9 on the second surface side Z2, which is the other surface side opposite to the first surface side Z1. . The uneven surface 8 has a concave portion 81 and a convex portion 82 as viewed from the first surface side Z1 side. The uneven surface 9 has a concave portion 91 and a convex portion 92 as viewed from the second surface side Z2 side. Here, the concave portion 81 and the convex portion 92 are in a front / back relationship, and the concave portion 91 and the convex portion 82 are in a front / back relationship.

As shown in FIGS. 7 and 8, the uneven surface 8 and the uneven surface 9 have the following configuration.
The uneven surface 8 includes a bottom 81B (hereinafter also referred to as a concave bottom 81B) of the concave 81, a top 82T of the convex 82 (hereinafter also referred to as a convex top 82T), and a wall 3 connecting the convex top 82T and the concave bottom 81B. Is provided. The concave bottom portion 81B is composed of the outer fiber layer 2 forming a flat surface on the second surface side Z2. The convex top portion 82T is composed of the outer surface fiber layer 1 that forms the flat surface of Z1 on the first surface side. The wall portion 3 is a common wall that forms the side surfaces of the concave portion 81 and the convex portion 82 and separates the concave portion 81 and the convex portion 82.
The uneven surface 9 includes a bottom 91B (hereinafter also referred to as a concave bottom 91B) of the concave 91, a top 92T (hereinafter also referred to as a convex top 92T) of the convex 92, and a wall 3 connecting the convex top 92T and the concave bottom 91B. Is provided. The concave bottom portion 91B is composed of an outer fiber layer 1 that forms a flat surface on the first surface side Z1. The convex top portion 92T is composed of the outer surface fiber layer 2 forming a flat surface on the second surface side Z2. The wall 3 is a side wall of the concave portion 91 and the convex portion 92, and is a common wall for the concave portion 91 and the convex portion 92.
The top portion 82T and the bottom portion 91B are configured by a common outer fiber layer 1. The top portion 92T and the bottom portion 81B are configured by the common outer fiber layer 2. Furthermore, the wall 3 is a common wall for the recess 81 and the recess 91.

  As shown in FIGS. 7 and 8, the wall 3 extends in the vertical direction with respect to the first surface side Z1 which is the one surface side or the second surface side Z2 which is the opposite surface side. More specifically, the wall 3 connects the ends of the outer fiber layers 1 and 2 in the vertical direction at both ends 39 and 39 and surrounds the above-described recess 81 from the side. That is, the wall 3 forms an outer wall that surrounds the four sides of the recess 81 on the first surface side Z1. Thereby, the inside of the recessed part 81 forms the independent space. In the present embodiment, a box-shaped space is formed by the four wall portions 3. However, the number of the wall parts 3 surrounding the recessed part 81 and the recessed part shape formed by the wall part 3 are not limited to this.

  The recess 81 has a depth H8 and an opening 83 having an opening diameter W8 on the first surface side Z1. The recess 91 has a depth H9 and an opening 93 having an opening diameter W9 on the second surface side Z2. The depths H8 and H9 may or may not be the same depth. In order to thicken the wall part 3 and improve the concealability of the whole nonwoven fabric, it is preferable to have a different depth. In order to make the wall part 3 thin and to improve the visibility of the colored object from the upper side in the oblique direction with respect to the wall part 3, it is preferable to have an equivalent depth.

Further, the concealment property of the colored object when viewed through the wall portion is changed from the relationship between the depth H8 of the concave portion 81, the opening diameter W8 of the opening portion 83, and the opening diameter W9 of the opening portion 93. In other words, depending on the relationship, when the angle β (see FIG. 1) of the oblique viewpoint described above is small and the viewing angle is low, the convexity 82 and the convexity 92 obstruct the hiding property. In addition, when the angle β of the oblique viewpoint is large and the viewing angle is high, the concave bottom portion 81B and the concave bottom portion 91B are viewed, and the concealment property is enhanced. Therefore, there is a preferred angle β for viewing the wall 3 depending on the relationship between the depth H8 of the recess 81, the opening diameter W8 of the opening 83, and the opening diameter W9 of the opening 93.
That is, for example, when a colored object (see FIG. 1) is viewed from the opening 83 side through the opening 93 through the wall 93, the angle β and the depth H8 of the recess 81, the opening diameter W8 of the opening 83, the opening 93 It is preferable that there is a relationship such as the following mathematical formula (R1) between the opening diameter W9.
(H8 / W8) ≧ tan β ≧ (H8 / (W8 + W9)) (R1)
When a colored object is viewed from the wall 3 through the next opening 93, the following formula is used between the angle β and the depth H8 of the recess 81, the opening diameter W8 of the opening 83, and the opening diameter W9 of the opening 93. It is preferable that there is a relationship of (R2).
(H8 / (2 × W8 + W9)) ≧ tan β ≧ (H8 / (2 × W8 + 2 × W9)) (R2)
When viewing a colored object from the wall 3 through the N-th opening 93, the angle β and the depth H8 of the recess 81, the opening diameter W8 of the opening 83, and the opening diameter W9 of the opening 93 are It is preferable that the following mathematical formula (R3) is satisfied.
(H8 / (N × (W8 + W9) −W9)) ≧ tan β ≧ (H8 / (N × (W8 + W9))) (R3)

By setting the angle β of the oblique viewpoint to the above range, it is easy to confirm a colored object (see FIG. 1) drawn through the wall 3 to the depth direction of the nonwoven fabric 10. That is, the concealment property is lowered by setting the angle β viewed from an oblique viewpoint within the above range. Further, by setting the angle β viewed from an oblique viewpoint within the above range, the above-described difference in concealment rate (E _β −E _α ) becomes large. A range in which a colored object (see FIG. 1) drawn into the depth direction of the nonwoven fabric 10 can be easily confirmed when viewed through the wall 3 at an angle β of an oblique viewpoint, or a range in which the concealability is reduced, Alternatively, from the viewpoint of widening the range in which the difference in concealment ratio is increased, it is preferable to increase the opening diameter W9 of the opening 93, and the ratio of the opening diameter W9 of the opening 93 to the opening diameter W8 of the opening 83 is increased. Is preferred. When viewed through the wall 3 at an angle β at an oblique viewpoint, the colored object (see FIG. 1) drawn into the depth direction of the nonwoven fabric 10 can be easily confirmed or concealed suddenly. From the viewpoint of making it possible to realize high absorbency with a surprise by lowering or the difference in concealment rate suddenly increasing, it is preferable to increase the depth H8, and the depth of the opening 83 relative to the opening diameter W8 It is preferable to increase the ratio of H8.
The above-described relationship between the angle β of the oblique viewpoint and the depth H8 of the recess 81, the opening diameter W8 of the opening 83, and the opening diameter W9 of the opening 93 is not limited to the nonwoven fabric 10D, and the unevenness such as the nonwoven fabric 10B described above. It can be applied to various forms of nonwoven fabrics having a surface.

  Furthermore, the wall 3 is disposed along the longitudinal direction (Y direction) of the nonwoven fabric 10D and the width direction (X direction) of the nonwoven fabric 10D as surrounding the recess 81. And a second wall portion 32. As shown in FIG. 7, the first wall portion 31 connects the end portion 11A of the first outer fiber layer 1 (11) and the end portion 2A of the outer fiber layer 2 in the vertical direction. As shown in FIG. 8, the second wall portion 32 connects the end portion 12 </ b> A of the first outer fiber layer 1 (12) and the end portion 2 </ b> A of the outer fiber layer 2 in the vertical direction. 7 and 8, the surface of the second surface side Z2 when placed on a horizontal plane with the second surface side Z2 down is shown as a nonwoven fabric reference surface 10SS (hereinafter also referred to as a reference surface 10SS). ). Hereinafter, the longitudinal section along the width direction (X direction) of the nonwoven fabric 10D shown in FIG. 7 is also referred to as an F1-F1 section. A longitudinal section along the longitudinal direction (Y direction) of the nonwoven fabric 10D shown in FIG. 8 is also referred to as an F2-F2 section.

The wall 3 stands up at an angle θ in the thickness direction with respect to the nonwoven fabric reference surface 10SS. The angle θ of the wall 3 is defined by the surface of the wall 3 (a straight line corresponding to the surface of the wall 3 in the cross section) and the reference plane 10SS in the longitudinal cross section (F1-F1 cross section or F2-F2 cross section) at the center of the recess 81. Is the angle formed by The angle θ in the F1-F1 cross section is θ1, and the angle θ in the F2-F2 cross section is θ2. It is preferable that both the angles θ1 and θ2 are within the following specified values (hereinafter, the angles θ1 and θ2 are collectively referred to as the angle θ).
The angle θ is larger than 80 °, preferably 85 ° or more from the viewpoint of making it difficult to see the colored material inside or below the nonwoven fabric 10 from the wall 3 when viewed from above in the direction perpendicular to the nonwoven fabric reference surface 10SS. And more preferably 89 ° or more. And the said angle (theta) is smaller than 100 degrees, Preferably it is 95 degrees or less, More preferably, it is 91 degrees or less. In other words, the vertical direction in which the wall portion 3 extends is set so as to be along the direction viewed from above the vertical direction V shown in FIG.
In addition, even if the angle θ of the wall portion 3 with respect to the nonwoven fabric reference surface 10SS is partially outside the above range between the upper end portion 3A and the lower end portion 3B of the wall portion 3, it is allowed. For example, the wavy shape of the wall 3 viewed in the longitudinal section may be between the upper end 3A and the lower end 3B of the wall 3.

Specifically, the angle θ of the wall 3 can be measured as follows.
First, the nonwoven fabric 10 is moved from the first surface side Z1 surface to the second surface side Z2 surface or from the second surface side Z2 surface to the first surface side Z1 surface so as to include the uneven surface 8 or the uneven surface 9. Cut toward it to obtain a longitudinal section (F1-F1 section or F2-F2 section).
Next, the nonwoven fabric 10 is left to stand so that the reference surface 10SS is horizontal, and the concave section 81, the convex section 82, the wall section 3, or the longitudinal section including the concave section 91, the convex section 92, and the wall section 3 (F1-F1 section or F2-F2 cross section) is taken to obtain a cross-sectional image. The angle θ of the wall 3 is measured from the captured cross-sectional image.
As one method for measuring the angle θ, the angle formed between the surface of the wall 3 to be viewed and the reference surface 10SS is measured, and is defined as the angle θ of the wall 3. Specifically, a virtual plane J1 from the intersection 3B of the concave bottom 81B and the wall 3 toward the end 3A of the convex 82, or an intersection 3C of the concave bottom 91B and the wall 3 toward the end 3D of the convex 92 is shown. A virtual plane J2 is set. The angle formed by the virtual surface J1 or J2 and the reference surface 10SS can be measured to obtain the angle θ of the wall 3 (see FIG. 9A).
When the surface of the wall 3 to be viewed is not flat but is a concavo-convex surface, the convex top of the concavo-convex surface of the wall 3 is on the outside of the wall (on the side of the concave portion 8 or the concave portion 9 according to the viewing side) The virtual plane J3 or J4 is set so as to be in contact with. The angle formed by the virtual surface J3 or J4 and the reference surface 10SS is measured and set as the angle θ of the wall portion 3 (see FIG. 9B).
In the case where the wall 3 is perforated, a convex surface is formed from the virtual plane J5 from the intersection 3B of the concave bottom 81B and the wall 3 toward the end 3A of the convex 82, or from the intersection 3C of the concave bottom 91B and the wall 3. A virtual plane J6 toward the end 3D of 92 is set. The angle formed by the virtual surface J5 or J6 and the reference surface 10SS can be measured to obtain the angle θ of the wall 3 (see FIG. 9C).
Note that the end portion 3 </ b> A of the convex portion 82 is a start point or an end point of the opening diameter W <b> 8 of the opening portion 83 in the concave portion 81 adjacent to the convex portion 82. The end portion 3D of the convex portion 92 is a start point or an end point of the opening diameter W9 of the opening portion 93 in the concave portion 81 adjacent to the convex portion 92.

It is preferable that the wall part 3 surrounding the recessed part 81 from the side part inclines to the same extent, respectively. That is, it is preferable that the angle θ of each wall portion is the same.
When the angle θ of each wall 3 with respect to the nonwoven fabric reference surface 10SS is the same, when viewed from the MD direction and the CD direction of the nonwoven fabric, the effect of reducing concealment at the same angle is obtained, and the nonwoven fabric looks uniform. There is an effect.
Moreover, it is also preferable that the wall part 3 which encloses the recessed part 81 from a side part inclines at a different angle, respectively. That is, it is preferable that the angle θ of each wall portion is different. When the angle θ of each wall portion 3 with respect to the nonwoven fabric reference surface 10SS is different, when the surface 10SA viewed by the nonwoven fabric is viewed from various angles, the effect of reducing the concealment at different angles is obtained, and the appearance after absorption Has the effect of adding a design to.
Furthermore, it is also preferable that a part of the wall part 3 surrounding the concave part 81 from the side part is inclined at the same degree and a part thereof is inclined at a different angle. In other words, among the angles θ of the wall portions, some angles θ are the same and other angles θ are different. For example, it is a case where MD of a nonwoven fabric, CD direction, and the angle of each wall part are the same. In this case, when viewed from the MD direction and the CD direction of the nonwoven fabric, it is possible to obtain the effect of reducing the concealment property at the same angle, and the effect of adding a design to the appearance after absorption.

  Furthermore, although not illustrated, in the nonwoven fabric 10D, the outer surface fiber layers 1 and 2 and the wall portion 3 are integrated with each other at least partly by fusion of at least some of the fibers. The nonwoven fabric 10D is bulky and thick by the wall 3 connecting and supporting the outer surface fiber layer 1 on the first surface side Z1 and the outer surface fiber layer 2 on the second surface side Z2. The thickness of the nonwoven fabric 10D refers to the apparent thickness in the shaped shape of the entire nonwoven fabric, not the local thickness of the outer fiber layers 1 and 2 and the wall 3. Note that in the nonwoven fabric 10D, the outer fiber layers 1 and 2, the wall portion 3, and each portion other than the connecting portion are fused at least at some intersections of the fibers. Moreover, the nonwoven fabric 10D may have an intersection which is not fused. Further, the nonwoven fabric 10D may include fibers other than thermoplastic fibers, and includes a case where the thermoplastic fibers are fused at intersections with other fibers.

The basis weight of the wall part 3 is made smaller than the basis weights of the convex top part 82T (concave bottom part 91B) and the concave bottom part 81B (convex top part 92T). Accordingly, the wall 3 has a light transmittance lower than that of the convex top portion 82T (concave bottom portion 91B) and the concave bottom portion 81B (convex top portion 92T).
That is, the concealability for the colored object when viewed from the upper side in the oblique direction with respect to the wall portion 3 is that for the colored object when viewed from the upper side in the vertical direction with respect to the convex top part 82T (concave bottom part 91B) and the concave bottom part 81B (convex top part 92T). It is lower than concealment. Thereby, in non-woven fabric 10D, the concealability with respect to a colored thing and the visibility which can recognize that the colored thing is pulled in back are compatible. The nonwoven fabric 10D can see the wall part 3 from an oblique viewpoint on the concavo-convex surfaces on both sides, and has the above effects on any surface side.
The vertical viewpoint and the oblique viewpoint have the same meanings as those shown in the above-described nonwoven fabrics 10A to 10C. Further, the difference in “concealment” is determined as a color difference indicated by ΔE ^* _ab defined by the nonwoven fabric 10A.
As a method of making the basis weight of the wall 3 smaller than the basis weight of the convex top portion 82T (concave bottom portion 91B) and the concave bottom portion 81B (convex top portion 92T), in addition to a method of newly laminating fibers and nonwoven fabrics, A method of preliminarily densifying the web is mentioned. In particular, when the web is processed, it is preferable because the web can be roughened. In such a case, as an example of a method in which the basis weight of the wall portion 3 is less than the basis weight of the convex top portion 82T (concave bottom portion 91B) and the concave bottom portion 81B (convex top portion 92T), there is a method by a web stretching process. This drawing process is performed when the fiber is previously formed into a web before fusing, and the web is formed with unevenness. In the drawing process, the constituent fibers 36 and 36 of the portion (see FIGS. 7 and 8) that becomes the convex top portion 82T (concave bottom portion 91B) and the portion (see FIGS. 7 and 8) that becomes the concave bottom portion 81B (convex top portion 92T); In the meantime, the portion of the constituent fiber 37 that becomes the wall portion 3 is stretched in the Z (Z1, Z2) direction (see FIG. 10). By extending | stretching at this time, the fabric weight of the wall part 3 reduces and a fabric weight becomes less than the convex peak part 82T (concave bottom part 91B) and the concave bottom part 81B (convex peak part 92T). Thereby, since the light scattering degree of the wall part 3 falls, light transmission amount improves and it becomes easy to see the inside of a nonwoven fabric through the wall part 3 from the diagonal direction.
In this case, since the drawing treatment is performed on the web before forming the non-woven fabric, the fibers can enhance the orientation of the fibers along the vertical direction formed by the wall 3. This is preferable because the visibility of the colored object in the lower back is enhanced in viewing from an oblique viewpoint, and the difference from the “hiding” by viewing from the vertical viewpoint becomes clearer.

The difference (N1−N2) between the basis weight (N1) of each of the convex top portion 82T (concave bottom portion 91B) and the concave bottom portion 81B (convex top portion 92T) and the basis weight (N1) of the wall portion 3 is a viewpoint of ensuring concealment. Therefore, it is 0 g / m ² or more, preferably 0.5 g / m ² or more, more preferably 1 g / m ² or more. In addition, the difference (N1-N2) is 100 g / m ² or less, preferably 50 g / m ² or less, more preferably 35 g / m ² or less, from the viewpoint of securing the difficulty of crushing the wall. is there.

The weight per unit area of the convex top portion 82T and the concave bottom portion 91B (outer surface fiber layer 1) is preferably 0.1 g / m ² or more, more preferably 1 g / m ² or more, from the viewpoint of ensuring concealment. Preferably it is 3 g / m ² or more. And from a viewpoint of ensuring hardness to crush of a wall part, Preferably it is 1000 g / m < ² > or less, More preferably, it is 100 g / m < ² > or less, More preferably, it is 50 g / m < ² > or less.

The weight per unit area of the concave bottom portion 81B and the convex top portion 92T (outer surface fiber layer 2) is preferably 0.1 g / m ² or more, more preferably 1 g / m ² or more, from the viewpoint of ensuring concealment. More preferably, it is 3 g / m ² or more. And from a viewpoint of ensuring hardness to crush of a wall part, Preferably it is 1000 g / m < ² > or less, More preferably, it is 100 g / m < ² > or less, More preferably, it is 50 g / m < ² > or less.

The weight per unit area of the wall part 3 is preferably 0.1 g / m ² or more, more preferably 0.5 g / m ² or more, and further preferably 1 g / m ² from the viewpoint of securing the difficulty of crushing the wall part. m ² or more. And from a viewpoint of ensuring visibility, Preferably it is 100 g / m < ² > or less, More preferably, it is 75 g / m < ² > or less, More preferably, it is 50 g / m < ² > or less.

The measuring method of the fabric weight of a nonwoven fabric cuts the nonwoven fabric of a measuring object into 10 cm x 10 cm, and uses it as a sample. If a 10 cm x 10 cm sample cannot be obtained, cut it into as large an area as possible. Using a balance, measure the mass of the sample to the second decimal place in g, and use the value obtained by dividing the measured value by the area of the sample as the basis weight.
The method for measuring the basis weight of each part of the nonwoven fabric cuts out each part from the nonwoven fabric to be measured. The cut width and length are precisely measured to the first decimal place in mm, and the sample is cut out until the total is 50 mm ² or more. The mass of the sample whose total is 50 mm ² or more is measured to the fourth decimal place in g units using a precision balance, and the value obtained by dividing the measured value by the area of the sample is taken as the basis weight.
When the nonwoven fabric to be measured is incorporated in a commercially available absorbent article, the nonwoven fabric is carefully peeled off from the absorbent article using a cold spray and used as a sample. At this time, if the hot melt adhesive is attached to the sample, the hot melt adhesive is removed using an organic solvent. This method is all the same for the measurement of other nonwoven fabrics in this specification.

Further, as described above, the nonwoven fabric 10D has a three-dimensional structure in which the wall 3 supports the outer surface fiber layers 1 and 2 that are flat surfaces in the vertical direction. With this three-dimensional structure, when the angle β of the oblique viewpoint is changed with respect to the nonwoven fabric reference surface 10SS, it is possible to confirm the excrement that is drawn to the back below the nonwoven fabric 10D at a certain angle. Thereby, the height of the absorption performance with respect to a colored thing (for example, excretion liquid) can be confirmed from the nonwoven fabric 10 surface.
From such a viewpoint, it is preferable that the apparent thickness and the basis weight are in the following ranges.

  The apparent thickness of the nonwoven fabric 10D is preferably 1.5 mm or more, more preferably 2 mm or more, from the viewpoint of facilitating confirmation of a colored object drawn through the wall 3 to the depth direction of the nonwoven fabric 10. More preferably, it is 3 mm or more. The upper limit of the apparent thickness is not particularly limited, but is preferably 100 mm or less, more preferably 50 mm or less, and still more preferably 10 mm or less, from the viewpoint of difficulty in crushing the wall portion. Moreover, when using as a surface material of an absorbent article, from a viewpoint which is excellent in portability etc., Preferably it is 10 mm or less, More preferably, it is 9 mm or less, More preferably, it is 8 mm or less.

[Measurement method of apparent thickness of nonwoven fabric 10D]
As a method for measuring the apparent thickness of the nonwoven fabric, first, the nonwoven fabric to be measured is cut into 10 cm × 10 cm to make a sample. If a 10 cm x 10 cm sample cannot be obtained, cut it into as large an area as possible. The apparent thickness of the nonwoven fabric is measured using a displacement sensor with a pressure of 50 Pa applied uniformly over the entire surface of the sample. Three points are measured, and the average of the three points is taken as the apparent thickness of the nonwoven fabric. An example of the displacement sensor is a high-precision displacement sensor ZS-LD80 (trade name) manufactured by OMRON Corporation.

  In the nonwoven fabric 10D of the present embodiment, it is preferable to set the content as follows using the above-described color tone changing material from the viewpoint of more effectively expressing the difference in “concealment”. That is, it is preferable that the content of the color change material is less in the wall portion 3 than in the convex top portion 82T (concave bottom portion 91B) and the concave bottom portion 81B (convex top portion 92T). Thereby, the light transmittance of the wall part 3 becomes lower than the convex top part 82T (concave bottom part 91B) and the concave bottom part 81B (convex top part 92T), and both "concealment" difference becomes clearer. The color change material is the same as that used in the nonwoven fabric 10D described with reference to FIG. Therefore, in the non-woven fabric 10D, the contents described for the non-woven fabric 10C described above, such as the measurement method of the color tone changing material, the method of inclusion, and the preferred content are applied.

Moreover, in this embodiment, as a method of including a color tone changing material, in addition to the coating method described for the nonwoven fabric 10C described above, a method of including in the constituent fibers of the nonwoven fabric in advance can be given. When the constituent fibers of the nonwoven fabric are composed of a plurality of resins, the plurality of resins may be evenly mixed with the color change material. In addition, the plurality of resins may contain the color tone changing material non-uniformly, or one resin or some of the plurality of resins may contain the color tone changing material. For example, in the case of a heat-fusible core-sheath fiber, it is preferable that there is a color tone changing material in the sheath part, and it is easy to express the difference in “hiding” more effectively. It is preferable that the heat-fusibility is not hindered. Further, when the nonwoven fabric is composed of a plurality of fibers, the plurality of fibers may contain the color change material equally, or the plurality of fibers may contain the color change material non-uniformly. A color changing material may be contained in one fiber or several fibers. In particular, it is preferable to process a web composed of a plurality of fibers because the content of the color-change material in the nonwoven fabric can be changed. In such a case, one example of a method in which the color tone changing material included in the wall portion 3 is less per unit volume than the color tone changing material included in the convex top portion 82T (concave bottom portion 91B) and the concave bottom portion 81B (convex peak portion 92T). As a method, there is a method by drawing a web. This stretching process is performed when a fiber including a color tone changing material is formed in advance on a web before fusion, and the web is unevenly shaped. In the drawing process, the constituent fibers 36 and 36 of the portion (see FIGS. 7 and 8) that becomes the convex top portion 82T (concave bottom portion 91B) and the portion (see FIGS. 7 and 8) that becomes the concave bottom portion 81B (convex top portion 92T); In the meantime, the portion of the constituent fiber 37 that becomes the wall portion 3 is stretched in the Z (Z1, Z2) direction (see FIG. 10). At this time, if the content of the color change material of the constituent fiber 36 and the constituent fiber 37 is different, the constituent fiber 36 having a large content becomes the convex top portion 82T (concave bottom portion 91B) and the concave bottom portion 81B (convex top portion 92T), and the content The constituent fiber 37 having a small amount becomes the wall portion 3. Further, by changing the content of the color tone changing material of the constituent fiber 36 and the constituent fiber 37, the content of the color changing material of the convex top portion 82T (concave bottom portion 91B), the concave bottom portion 81B (convex top portion 92T) and the wall portion 3 is obtained. Can be different.
By extending the wall 3 in the thickness direction of the nonwoven fabric 10D by the stretching process, the amount of color change material per unit volume of the wall 3 can be reduced. Thereby, the light transmission amount of the wall part 3 is improved, and the inside of the nonwoven fabric can be easily seen through the wall part 3 from an oblique direction. On the other hand, the amount of color change material of the top part 82T and the bottom part 81B does not change by the stretching process.
In this case, since the drawing treatment is performed on the web before forming the non-woven fabric, the fibers can enhance the orientation of the fibers along the vertical direction formed by the wall 3. This is preferable because the visibility of the colored object in the lower back is enhanced in viewing from an oblique viewpoint, and the difference from the “hiding” by viewing from the vertical viewpoint becomes clearer.

FIG. 11 shows a result of taking out an equal amount of fiber from each of the convex top portion, concave bottom portion, and wall portion when the above stretching process is performed, and measuring the mass change rate (DTG) / fiber input amount. The example of the difference of content of the color change material of a concave bottom part and a wall part is shown. 1 mg fiber is taken out from each of the convex top part, concave bottom part and wall part, put in φ5 open pan (aluminum), and measured at a heating rate of 10 ° C./min using STA7200RV (trade name) manufactured by Hitachi High-Tech Science Co., Ltd. Went. In this specific example, titanium oxide was used, and the mass change rate (DTG) of the wall portion was about 10% lower than the convex top portion and the concave bottom portion. That is, the titanium oxide ratio (TiO ₂ ratio) of the wall portion is lower than that of the convex top portion and the concave bottom portion, and the content of the color change material is reduced. Here, the TiO ₂ ratio is the content of the color tone changing material.

Furthermore, it is preferable to vary the fineness (fiber diameter) of the constituent fibers of the nonwoven fabric 10D as follows from the viewpoint of more effectively expressing the difference in “concealment”.
That is, it is preferable to increase the fineness of the fibers constituting the wall portion 3 from the fineness of the fibers constituting the convex top portion 82T (concave bottom portion 91B) and the fineness of the fibers constituting the concave bottom portion 81B (convex top portion 92T). Thereby, scattering of the light incident on the wall portion 3 is suppressed more than the convex top portion 82T (concave bottom portion 91B) and the concave bottom portion 81B (convex top portion 92T). That is, the light transmittance in the wall part 3 becomes higher than the convex top part 82T (concave bottom part 91B) and the concave bottom part 81B (convex top part 92T). As a result, the difference in “concealment” between the two becomes clearer.
As a method of changing the fineness of the fiber, there is a method in which a fiber having a different fineness is previously contained in the constituent fibers of the nonwoven fabric, in addition to a method of newly laminating a fiber having a different fineness. In particular, it is preferable to process a web composed of a plurality of fibers because the fineness in the nonwoven fabric can be changed. In such a case, as an example of a method for making the fineness of the fibers contained in the wall portion 3 thicker than the fineness of the fibers contained in the convex top portion 82T (concave bottom portion 91B) and the concave bottom portion 81B (convex top portion 92T), There is a method by stretching. This drawing process is performed when the fiber is previously formed into a web before fusing, and the web is formed with unevenness. In the drawing process, the constituent fibers 36 and 36 of the portion (see FIGS. 7 and 8) that becomes the convex top portion 82T (concave bottom portion 91B) and the portion (see FIGS. 7 and 8) that becomes the concave bottom portion 81B (convex top portion 92T); In the meantime, the portion of the constituent fiber 37 that becomes the wall portion 3 is stretched in the Z (Z1, Z2) direction (see FIG. 10). At this time, if the fineness of the fibers of the constituent fiber 36 and the constituent fiber 37 is different, the constituent fiber 36 having a relatively thin fineness becomes the convex top portion 82T (concave bottom portion 91B) and the concave bottom portion 81B (convex top portion 92T), and the fineness is relatively high. The thick constituent fiber 37 becomes the wall 3. Moreover, the fineness of the convex top part 82T (concave bottom part 91B), the concave bottom part 81B (convex top part 92T), and the wall part 3 can also be varied by changing the fineness of the constituent fiber 36 and the constituent fiber 37.
By extending the wall 3 in the thickness direction of the nonwoven fabric 10D by the stretching process, the fineness of the fibers of the wall 3 can be increased. Thereby, since the light scattering degree of the fiber of the wall part 3 falls, light transmission amount improves and it becomes easy to see the inside of a nonwoven fabric through the wall part 3 from the diagonal direction.
In this case, since the drawing treatment is performed on the web before forming the non-woven fabric, the fibers can enhance the orientation of the fibers along the vertical direction formed by the wall 3. This is preferable because the visibility of the colored object in the lower back is enhanced in viewing from an oblique viewpoint, and the difference from the “hiding” by viewing from the vertical viewpoint becomes clearer.

  The difference between the fineness of the fibers constituting the wall 3 and the fineness of the fibers constituting the convex top portion 82T (concave bottom portion 91B) and the concave bottom portion 81B (convex top portion 92T) is as follows. From the viewpoint of clarifying the difference in “concealment”, it is preferably 0.01 dtex or more, more preferably 0.05 dtex or more, and further preferably 0.1 dtex or more. The difference in fineness is preferably 10 dtex or less, more preferably 5 dtex or less, and even more preferably 1 dtex or less from the viewpoint of achieving both concealment and visibility.

  Moreover, the fineness of the fiber which comprises the convex top part 82T (concave bottom part 91B) and the concave bottom part 81B (convex top part 92T) is as follows. From the viewpoint of obtaining permeability of excreted matter to be absorbed, it is preferably 0.1 dtex or more, more preferably 0.5 dtex or more, and further preferably 1 dtex or more. And from a viewpoint of obtaining concealment property, Preferably it is 100 dtex or less, More preferably, it is 10 dtex or less, More preferably, it is 5 dtex or less.

  Moreover, the fineness of the fiber which comprises the wall part 3 is as follows. From the viewpoint of obtaining visibility that is larger than the fineness of the fibers constituting the convex top portion 82T (concave bottom portion 91B) and the concave bottom portion 81B (convex top portion 92T), it is preferably 0.1 dtex or more, more preferably 0.5 dtex. Or more, more preferably 1 dtex or more. And from a viewpoint of obtaining the concealability of the whole nonwoven fabric, Preferably it is 100 dtex or less, More preferably, it is 10 dtex or less, More preferably, it is 5 dtex or less.

[Measurement method of fineness]
The fineness of the fiber before processing the nonwoven fabric can be determined according to JIS L1015.
The fineness of the non-woven fabric and the fineness of the fiber at each part of the non-woven fabric can be determined from the fiber diameter of the fiber cross section. The cross-sectional shape of the fiber is measured with an electron microscope or the like, and the cross-sectional area of the fiber (the cross-sectional area of each resin component in a fiber formed of a plurality of resins) is measured. At the same time, the type of resin (approximate component ratio in the case of a plurality of resins) is specified by DSC (differential thermal analyzer), the specific gravity is determined, and the fineness is calculated. For example, in the case of a short fiber composed of polyethylene terephthalate (PET), the cross section is first observed and the cross sectional area is calculated. Then, by measuring with DSC, it is comprised from single-component resin from melting | fusing point and peak shape, and it identifies that it is a PET core. Thereafter, the fineness is calculated by calculating the mass of the fiber using the density and cross-sectional area of the PET resin.

Next, a more specific structure of the nonwoven fabric 10 (10D) will be described.
As illustrated in FIG. 6, the nonwoven fabric 10 </ b> D includes first and second outer fiber layers 11 and 12 as the outer fiber layer 1 on the first surface side Z <b> 1. The first and second outer fiber layers 11 and 12 have lengths extending along different directions intersecting each other in a plan view of the nonwoven fabric 10D. The extending directions are an X direction and a Y direction perpendicular to each other along the side of the nonwoven fabric 10D. The Y direction is the longitudinal direction of the nonwoven fabric 10D, and the X direction is the width direction of the nonwoven fabric 10D.

The first outer fiber layer 11 extends continuously without a break in the Y direction in a plan view of the nonwoven fabric 10D. That is, the 1st outer surface fiber layer 11 is continuing without a cut | interruption over the whole length direction of nonwoven fabric 10D. A plurality of the first outer fiber layers 11 are arranged apart from each other in the X direction orthogonal to the Y direction.
The second outer surface fiber layer 12 extends in the X direction, and is arranged by connecting between the first outer surface fiber layers 11 and 11 that are separated in parallel in the X direction. “Connecting the first outer fiber layers 11, 11” means that the second outer fiber layers 12 adjacent to each other with the first outer fiber layer 11 in between are arranged in a straight line. Specifically, the difference between the center line of the second outer fiber layer 12 and the center line of the second outer fiber layer 12 adjacent to each other across the first outer fiber layer 11 is the width of the second outer fiber layer 12. It means a range of (length in the longitudinal direction), for example, it is within 5 mm. The second outer fiber layer 12 is preferably formed so that the position of the first surface side Z1 is slightly lower than that of the first outer fiber layer 11. Therefore, the second outer fiber layer 12 is divided in length in the X direction by the first outer fiber layer 11 interposed, and a plurality of second outer fiber layers 12 are arranged in the X direction while being separated from each other. Moreover, it is preferable that the width (length in the Y direction) of the second outer surface fiber layer 12 is narrower than the width (length in the X direction) of the first outer surface fiber layer 11. A plurality of such second outer fiber layers 12 in the X direction are further spaced apart from each other in the Y direction. The shape of the second outer fiber layer is not limited to that of the present embodiment, and for example, the position and width of the first surface side Z1 may be the same as those of the first outer fiber layer 11.

  As described above, when the outer surface fiber layer 1 has a plurality of types having different extending directions, the “different directions intersecting in plan view” as the extending direction is not limited to the X direction and the Y direction. As long as the direction intersects in the plane direction of the nonwoven fabric 10D, various modes can be taken.

  A plurality of outer surface fiber layers 2 on the second surface side Z2 are spaced apart from each other. Specifically, a plurality are separated from each other along the extending direction (Y direction) of the outer surface fiber layer 11 so as to cover the separated space between the first outer surface fiber layers 11 on the first surface side Z1. And have a line. Furthermore, a plurality of rows in the Y direction of the outer surface fiber layers 2 are arranged apart from each other in the X direction orthogonal to the Y direction. That is, the outer fiber layer 2 is also arranged in the X direction. Thus, the arrangement direction of the outer surface fiber layer 2 coincides with the extending direction of the outer surface fiber layer 1 at a position where the surface does not overlap the outer surface fiber layer 1. Therefore, when the extending direction of the outer fiber layer 1 is different from the X direction and the Y direction, the arrangement direction of the outer fiber layer 2 is also different from the X direction and the Y direction accordingly.

  Moreover, as shown in FIGS. 6-8, the wall part 3 has the 1st wall part 31 which connects the 1st outer surface fiber layer 11 of the 1st surface side Z1, and the outer surface fiber layer 2 of the 2nd surface side Z2, It has the 2nd wall part 32 which connects the 2nd outer surface fiber layer 12 of the 1st surface side Z1, and the outer surface fiber layer 2 of the 2nd surface side Z2. A plurality of the wall portions 3 (first wall portion 31 and second wall portion 32) are arranged apart from each other in the plane direction of the nonwoven fabric 10D in accordance with the disposition of the outer surface fiber layers 1 and 2.

  A plurality of first wall portions 31 and second wall portions 32 constituting the wall portion 3 are arranged along different directions in which the nonwoven fabric 10D intersects in plan view. Specifically, the first wall portion 31 has a length that coincides with the side in the Y direction of the outer surface fiber layer 2 on the second surface side Z2, and the extension of the first outer surface fiber layer 11 on the first surface side Z1. A surface along the outgoing direction is provided. That is, the surface of the first wall portion 31 is arranged along the Y direction. On the other hand, the second wall portion 32 has a length that matches the side in the X direction of the outer surface fiber layer 2 on the second surface side Z2, and extends in the extending direction of the second outer surface fiber layer 12 on the first surface side Z1. With a surface along. That is, the surface of the second wall portion 32 is arranged along the X direction. Thus, the direction along the surface of the wall 3 (the first wall 31 and the second wall 32) is the same as the extension of the outer fiber layer 1 (the first outer fiber layer 11 and the second outer fiber layer 12). I'm doing it. Therefore, when the extending direction of the outer surface fiber layer 1 takes a direction different from the X direction and the Y direction, the direction along the surface of the wall portion 3 is also a direction different from the X direction and the Y direction accordingly.

As shown in FIG. 6, in any of the first wall portion 31 and the second wall portion 32 having different surface orientations, the constituent fibers 36 and 37 are oriented in the thickness direction of the nonwoven fabric 10D as shown in FIG. ing. In other words, regardless of the longitudinal direction and the width direction of the nonwoven fabric 10D, the wall 3 is a surface facing in any direction in the planar direction (for example, the X direction and the Y direction). The orientation in the thickness direction (Z direction) is enhanced. Just by shaping the non-woven fabric in which the fibers are oriented randomly and fused basically like the conventional non-woven fabric, the walls 3 oriented in different directions are thus oriented in the thickness direction. It cannot be. Even if there is an orientation, it is one direction of the machine flow direction during the production of the nonwoven fabric. On the other hand, the nonwoven fabric 10 of this embodiment is the thickness of nonwoven fabric 10D also in the wall part 3 which faces in any direction (the 1st wall part 31 and the 2nd wall part 32 which have a mutually orthogonal surface in this embodiment). Has longitudinal fiber orientation.
Thereby, irregular reflection of the light which permeate | transmits the wall part 3 is reduced, and it becomes easy to confirm the colored thing (for example, excrement) drawn in to the depth direction of a nonwoven fabric, and also the thickness direction depth from the surface of a nonwoven fabric It seems to absorb.

The uneven surface 8 described above is disposed on the first surface side Z1 of the nonwoven fabric 10D.
The uneven surface 8 has a concave portion 81 surrounded by four wall portions 3 (two first wall portions 31 and two second wall portions 32). The recess 81 is in a region in the thickness direction from the region on the first surface side Z1 defined by the first outer surface fiber layer 11 and the second outer surface fiber layer 12 to the outer surface fiber layer 2 on the second surface side Z2. . The concave portion 81 has the outer surface fiber layer 2 on the second surface side Z2 as the bottom, and opens to the first surface side Z1. By providing the concave portion 81, at least a part of light from oblique directions in all directions with respect to the nonwoven fabric reference surface 10SS is easily transmitted through the wall portion 3. Thereby, it becomes easy to see the colored object (for example, excrement) drawn in to the depth direction back of the nonwoven fabric 10 even if it is a case where it sees from any direction of an oblique viewpoint.

  The concave portion 81 is surrounded by four wall portions 3 erected from the four sides of the outer surface fiber layer 2 on the second surface side Z2. Therefore, a plurality of the recesses 81 are arranged so as to be spaced apart from each other, corresponding to the arrangement of the outer fiber layer 2 in the X direction and the Y direction. In this arrangement, the recesses 81 are independent without communicating with each other.

  Furthermore, the presence of the concave portion 81 seems to feel psychologically good. In addition, when used as a surface material for diapers, the opening is reminiscent of breathability and gives a comfortable feeling. In addition, the space is preserved to create a passage for the air, and the air permeability is actually improved, reducing the stuffiness.

  In the present embodiment, the plurality of independent recesses 81 are connected in the Y direction by the first outer fiber layer 11 while being separated from each other. Thereby, the shape of the surface of the first surface side Z1 of the nonwoven fabric 10 is easily maintained. Moreover, since the first outer fiber layer 11 and the second outer fiber layer 12 have different heights on the first surface side Z1, the spread of the pressing force in the planar direction of the nonwoven fabric 10 is suppressed, which is preferable.

On the second surface side Z2 of the nonwoven fabric 10D, the uneven surface 9 on the second surface side Z2 described above is disposed.
The uneven surface 9 has two types of concave portions 91 corresponding to each of the two types of the outer surface fiber layer 1 (the first outer surface fiber layer 11 and the second outer surface fiber layer 12). Specifically, the first outer surface fiber layer 11 has a recess 911 whose bottom is a bottom portion, and the second outer surface fiber layer 12 has a recess 912 whose bottom portion is a bottom. On the second surface side Z2, the concave portion 911 is continuous in the Y direction, the concave portion 912 is continuous in the X direction, and the concave portion 911 and the concave portion 912 are in communication.

Next, a preferred embodiment of a method for producing the nonwoven fabric 10D will be described below with reference to FIG.
In the manufacturing method of the nonwoven fabric 10D of the present embodiment, the support male material 120 and the support female material 130 for shaping the fiber web 110 before forming the nonwoven fabric are used. As shown in FIG. 12 (A), the fiber web 110 is placed on the support male material 120 and sandwiched by the support female material 130 from above the fiber web 110 for shaping.

  The support male material 120 has a large number of protrusions 121 corresponding to positions where the four wall portions 3 surrounding the concave portion 81 of the nonwoven fabric 10D and the outer surface fiber layer 2 on the second surface side Z2 are shaped. A space between the protrusions 121 and 121 is a support recess 122 corresponding to a position where the outer fiber layer 1 on the first surface side Z1 is shaped. Thereby, the support male material 120 has an uneven shape, and the protrusions 121 and the support recesses 122 are alternately arranged in different directions in plan view. The support bottom portion 123 of the support recess 122 has a structure in which hot air blows through, for example, a large number of holes (not shown). In addition, it is preferable that the said "different direction" is a direction which corresponds to the Y direction (longitudinal direction) and X direction (width direction) in nonwoven fabric 10D as a support body which manufactures nonwoven fabric 10D. In the manufacturing method of this embodiment, the Y direction corresponds to the machine flow direction, and the X direction corresponds to the width direction orthogonal to the machine flow direction. However, “different directions” are different depending on the uneven structure of the nonwoven fabric of the present invention, and are not limited to the Y direction and the X direction.

  The support female member 130 has lattice-like protrusions 131 corresponding to the support concave portion 122 of the support male member 120. A space between the protrusions 131 and 131 is a support recess 132 corresponding to the protrusion 121 of the support male member 120. Thus, the support female member 130 has an uneven shape, and the protrusions 131 and the support recesses 132 are alternately arranged in different directions in plan view. The support bottom portion 133 of the support recess 132 has a structure through which hot air blows through. For example, a large number of holes are provided. The distance between the protrusions 131 is greater than the width of the protrusion 121 of the support male member 120. The distance is appropriately set so that the wall 3 in which the fiber web 110 is sandwiched between the protrusion 121 of the support male member 120 and the protrusion 131 of the support female member 130 and the fibers are oriented in the thickness direction can be suitably shaped. .

  First, in this embodiment, the fiber web 110 before being fused is supplied from a card machine (not shown) to an apparatus for shaping the web so as to have a predetermined thickness.

  Next, as shown in FIG. 12A, a fiber web 110 containing thermoplastic fibers is disposed on the support male material 120, and the support female material 130 is pushed into the support male material 120 from the fiber web 110. At this time, the protrusion 121 of the support male member 120 is inserted into the support recess 132 of the support female member 130. Further, the protrusion 131 of the support female member 130 is inserted into the support recess 122 of the support male member 120. This creates a shape in which the fibers are oriented in the thickness and plane directions.

In this state, as shown in FIG. 12B, the first hot air W1 is blown against the fiber web 110 from the support female member 130 side. That is, the 1st hot air W1 is sprayed from the side used as the 2nd surface in the nonwoven fabric 10. FIG. Thereby, the fiber web 110 is fused to such an extent that the uneven shape of the nonwoven fabric 10 can be maintained. In the fiber web 110, the fibers are in a very loosely fused state.
Further, between the top of the protrusion 121 and the bottom of the support recess 132, the first hot air W1 is prevented from being blown through, and the fibers are fused in the planar direction. Thereby, the fiber layer equivalent to the outer surface fiber layer 2 of the 2nd surface side Z2 is shaped. Further, the fibers are oriented in the planar direction between the bottom of the support recess 122 and the top of the protrusion 131. Since the protrusion 131 inhibits hot air, the formed fiber layer is less fused and a smooth fiber layer is obtained. Thereby, the fiber layer equivalent to the outer surface fiber layer 1 of the 1st surface side Z1 is shaped. At this time, the shape of the wall portion oriented in the thickness direction is also maintained.
In addition, the arrow in drawing shows the flow of the 1st hot air W1 typically.

The temperature of the first hot air W1 is set to a temperature at which the thermoplastic fiber can maintain its shape in the thickness direction and the planar direction. Considering a general fiber material used for this type of product, it is preferably 0 ° C. or more and 70 ° C. or less, preferably 5 ° C. or more and 50 ° C. or less higher than the melting point of the thermoplastic fiber constituting the fiber web 110. More preferred.
The wind speed of the first hot air W1 is preferably 2 m / s or more and more preferably 3 m / s or more from the viewpoint of effectively fusing. In addition, the wind speed of the first hot air W1 is preferably 100 m / s or less, and more preferably 80 m / s or less, from the viewpoint of making the apparatus scale compact.
In this way, the fiber web 110 is temporarily fused and held in an uneven shape.
In addition, the height of the protrusion 121 of the support male member 120 and the height of the protrusion 131 of the support male member 130 are appropriately determined depending on the apparent thickness of the nonwoven fabric 10 to be manufactured. For example, 2 mm or more is preferable, 3 mm or more is more preferable, 5 mm or more is further preferable, 15 mm or less is preferable, 10 mm or less is more preferable, and 9 or less is still more preferable.

Next, the support female member 130 is removed, and as shown in FIG. 12C, the second hot air W2 at a temperature at which each fiber of the fiber web 110 shaped into a concavo-convex shape can be appropriately fused is blown. To attach the fibers together. Also in this case, similarly to the first hot air W1, the second hot air W2 is blown against the fiber web 110 from the side that becomes the second surface of the nonwoven fabric 10. The temperature of the second hot air W2 at this time is 0 ° C. or more and 70 ° C. or less higher than the melting point of the thermoplastic fiber constituting the fiber web 110 in consideration of a general fiber material used for this type of product. It is more preferable that the temperature is higher by 5 ° C. or more and 50 ° C. or less.
Although the wind speed of the 2nd hot air W2 is based also on the height of the protrusion 121 of the support body male material 120, 2 m / s or more is preferable and 3 m / s or more is more preferable. Thereby, the heat transfer to the fibers can be made sufficient, the fibers can be fused together, and the uneven shape can be fixed sufficiently. The wind speed of the second hot air W2 is preferably 100 m / s or less, and more preferably 80 m / s or less. Thereby, excessive heat transfer to a fiber can be suppressed and the texture of the nonwoven fabric 10 can be made favorable.
In addition, the process of spraying the first hot air W1 can be omitted by reducing the surface roughness of the female support member. Further, by reducing the surface roughness, it is possible to remove the support female member 130 in the step of blowing the second hot air W2 without clinging the unfused fibers. That is, after producing the web, the support male member 120 and the support female member 130 can be fitted together, the support female member 130 can be removed as it is, and the treatment can be performed with the second hot air W2. Thereby, it becomes a simpler process.

As a thermoplastic fiber, what is normally used as a raw material of a nonwoven fabric can be employ | adopted without a restriction | limiting in particular. For example, the fiber which consists of a single resin component, the composite fiber which consists of a some resin component, etc. may be sufficient. Examples of the composite fiber include a core-sheath type and a side-by-side type.
When a composite fiber containing a low melting point component and a high melting point component (for example, a core-sheath type composite fiber having a low melting point component and a core having a high melting point component) is used as the thermoplastic fiber, the temperature of the hot air blown onto the fiber web 110 is low. The melting point is preferably equal to or higher than the melting point of the melting point component and lower than the melting point of the high melting point component. More preferably, the temperature is at least 10 ° C lower than the melting point of the high melting point component, more preferably at least 5 ° C higher than the melting point of the low melting point component, and more preferably at least 20 ° C lower than the melting point of the high melting point component. .

  As described above, the nonwoven fabric 10D is produced. Between the protrusion 121 of the support male member 120 and the protrusion 131 of the support female member 130, the fibers of the fiber web 110 are aligned and oriented in the thickness direction, and the wall portion 3 is formed. At this time, the wall 3 in which the fibers are oriented in the thickness direction (longitudinal direction) is formed on the surface facing the protrusion 121 in any direction. Thereby, the recessed part 81 by which the side surface was enclosed by the four wall parts 3 which nonwoven fabric 10D has is formed. In addition, the outer surface fiber layer 2 on the second surface side Z2 in which the fibers are oriented in the planar direction is formed between the top of the protrusion 121 and the bottom of the support recess 132. Further, the outer surface fiber layer 1 on the first surface side Z1 in which the fibers are oriented in the planar direction is formed between the bottom of the support recess 122 and the top of the protrusion 131.

  In the obtained nonwoven fabric 10D, the lower surface in FIG. 12C is the first surface side Z1, and the opposite surface is the second surface side Z2. That is, the first surface side Z1 in the nonwoven fabric 10D is the side on which the support male material 120 is disposed, and the second surface side Z2 is the side on which the first hot air W1 and the second hot air W2 are blown. Therefore, the fusion | melting point of the fibers of the outer surface fiber layer 2 of the 2nd surface side Z2 increases more than the outer surface fiber layer 1 of the 1st surface side Z1 from the difference in the amount of blowing of the 1st hot air W1. Furthermore, due to the difference in the amount of heat, the surface of the outer surface fiber layer 1 on the first surface side Z1 is less rough and feels better than the surface of the outer surface fiber layer 2 on the second surface side Z2. Even if the step of blowing the first hot air W1 is omitted, the same effect can be obtained by the distance from the second hot air W2. In addition, by inserting the support male material 120 into the support female material 130 with the fiber web 110 sandwiched therebetween, the fibers of the outer surface fiber layer 2 on the second surface side Z2 are pulled, and more to the support male material 120. Head to. Therefore, the outer surface fiber layer 1 on the first surface side Z1 formed on the bottom of the support concave portion 122 of the support male material 120 has a second surface side Z2 formed on the top of the projection 121 of the support male material 120. The amount of fibers in the outer fiber layer 2 is reduced.

  In the manufacturing method of the present embodiment, in consideration of continuous production, it is preferable that the apparatus incorporating the support male material 120 and the support female material 130 is of a conveyor type or a drum type that can be conveyed. Moreover, after removing the support body material 130, it is preferable to peel off the shaped nonwoven fabric 10 from the support body material 120, and to wind up in roll shape (not shown).

  In this manufacturing method, the thickness of the nonwoven fabric 10D is appropriately determined depending on the height of the protrusion 121 of the support male member 120 and the protrusion 131 of the support female member 130. For example, when the height of the protrusion is increased, the apparent thickness of the sheet is increased, and when the height is decreased, the apparent thickness of the sheet is decreased. Further, when the height of the protrusion is increased, the fiber density of the nonwoven fabric 10D is decreased, and when the height is decreased, the fiber density of the nonwoven fabric 10D of the sheet is increased.

  The nonwoven fabric 10 (10A-10D) demonstrated in each embodiment is applicable to the surface sheet of absorbent articles, such as a sanitary napkin and a disposable diaper, for example. When using as a surface sheet, you may use which surface faces a wearer's skin surface. However, when viewed at a different angle with respect to the nonwoven fabric reference surface, it is easy to confirm excrement drawn into the depth direction of the nonwoven fabric at a certain angle, and the impression that it is absorbed from the nonwoven fabric surface to the depth direction From the viewpoint of easily recalling, it is preferable to use the first surface side Z1 toward the wearer's skin surface side. In addition, from the viewpoint of excellent cushioning properties and soft touch, it is preferable to use the first surface side Z1 opposite to the surface to which hot air is applied at the time of manufacture, facing the wearer's skin surface side. This is preferable because the number of points is relatively small and the texture is smooth.

  Next, a basic configuration of a thin sanitary napkin 100 using the nonwoven fabric 10 as a top sheet will be described below with reference to FIG. In FIG. 13, the width direction of the sanitary napkin 100 is indicated by X, and the longitudinal direction is indicated by Y.

  As shown in FIG. 13, the sanitary napkin 100 includes a vertically long main body 104. The main body 104 includes a liquid-permeable top sheet 101 disposed on the skin contact surface side, a liquid-impermeable back sheet 102 disposed on the non-skin contact surface side, the top sheet 101, and the back sheet 102. And an absorbent body 103 having liquid retaining properties interposed between the two. On both sides of the main body 104, wings 105 (105a, 105b) extending outward are provided. In the drawing, the wing 105 is shown in a folded state.

  The shape of the main body 104 is a vertically long shape having a longitudinal direction (Y direction) arranged from the lower abdomen side to the buttocks side through the wearer's crotch portion and a width direction (X direction) perpendicular thereto. Shape. In the present invention, unless otherwise specified, the side in contact with the human body is referred to as the skin contact surface side or the surface side, and the side in contact with the underwear is referred to as the non-skin contact surface side or the back surface side. Furthermore, a direction having a relatively long length in plan view of the sanitary napkin 100 is referred to as a longitudinal direction, and a direction orthogonal to the longitudinal direction is referred to as a width direction. The longitudinal direction typically coincides with the front-rear direction of the human body in a worn state.

  The nonwoven fabric 10 is used for the topsheet 101. In that case, it arrange | positions so that the recessed part 81 may become the skin contact surface side.

The back sheet 102 is not particularly limited as long as it is waterproof and has moisture permeability. For example, a film as described in JP2013-128628A is used.
As the absorber 103, for example, a fiber assembly or a combination of this and an absorbent polymer can be used. For example, a fiber assembly as described in JP2013-128628A is used. Moreover, you may use the coating sheet (not shown) which coat | covers the absorber 103. FIG.
The wing 105 is made of a soft non-woven fabric having water repellency, bulkiness and low fiber density, and its base is sandwiched and fixed between the top sheet 101 and the back sheet 102. For the wing 105, for example, a non-woven fabric as described in JP2013-128628A is used.

  Since the sanitary napkin 100 uses the non-woven fabric 10 for the topsheet 101, when viewed at a different angle with respect to the non-woven fabric reference surface 10SS (see FIG. 1), the depth of the non-woven fabric 10 in the thickness direction at a certain angle. It becomes easy to confirm the excretions drawn in. Moreover, it becomes easy to recall the impression absorbed in the depth direction from the surface of the nonwoven fabric, and it seems to be absorbed in the depth direction from the surface. In other words, holding the sanitary napkin 100 in the hand and looking at the reference plane 10SS, the excrement drawn to the back can be confirmed by twisting the hand, and the impression absorbed in the back is recalled. Can do. Here, “hand” refers to the fingertip from the shoulder, including the arm. In addition, twisting the hand mainly means twisting the wrist or forearm. Here, by twisting the hand, it feels as if the hand has been twisted by more than 10 °, it feels as if the hand has been twisted to the limit 80 °, and it feels as if the hand has been twisted to the limit Is 80 °. Further, it is 90 ° or more to feel as if the hand is twisted to the limit on the inside, and 80 ° is felt as if the hand is twisted to the limit on the outside. For this reason, by using the nonwoven fabric 10 whose concealability is lowered in the oblique direction S for the sanitary napkin 100, it is possible to impart a function of changing the impression when the hand is twisted. Moreover, the nonwoven fabric 10 can obtain the same effect not only as a surface sheet but also as a back sheet, an intermediate sheet between the top sheet and the back sheet, and an absorbent sheet.

  The nonwoven fabric of this invention can be used for various uses. For example, it can be suitably used as a surface sheet for absorbent articles such as disposable diapers for adults and infants, sanitary napkins, panty liners, urine absorption pads and the like. Furthermore, it can also be used as a sublayer interposed between a surface sheet such as a sanitary product or a diaper and an absorbent body, or a covering sheet (core wrap sheet) of the absorbent body.

  EXAMPLES Hereinafter, although this invention is demonstrated in more detail based on an Example, this invention is limited to this and is not interpreted. In this example, “%” is based on mass unless otherwise specified.

Example 1
6 includes the manufacturing process shown in FIG. 12 using thermoplastic fibers having a fineness of 1.5 to 1.6 dtex containing 2.7 to 3% by mass of titanium oxide (TiO ₂ ) as a color change material. It produced by the air through manufacturing method. This was used as the nonwoven fabric sample of Example 1. The blowing process using the first hot air W1 was performed under the conditions of a temperature of 160 ° C., a wind speed of 55 m / s, and a blowing time of 3 seconds. The second hot air blowing treatment was performed under the conditions of a temperature of 160 ° C., a wind speed of 55 m / s, and a blowing time of 3 seconds.
The nonwoven fabric sample of Example 1 had an apparent thickness of 7.2 mm. The depth H8 of the recess 81 was 6 mm, and the opening diameter W8 was 2 mm in the CD direction and 3 mm in the MD direction. The depth H9 of the recess 91 was 6 mm, and the opening diameter W9 was 2 mm in the CD direction and 1.5 mm in the MD direction. The convex top portion 82T had a mass change rate (hereinafter also referred to as DTG) / fiber input of 30% / min. The concave bottom portion 81B had a DTG / fiber input amount of 30% / min. Wall part 3 had a DTG / fiber input of 27% / min. The angle θ of the wall portion, the basis weight, the TiO ₂ ratio, the concealment rate, and the fineness were as shown in Table 1.

(Example 2)
The nonwoven fabric sample of Example 2 was obtained by turning over the nonwoven fabric sample produced in the same manner as in Example 1.
The nonwoven fabric sample of Example 2 had an apparent thickness of 7.2 mm. The depth H8 of the recess 81 was 6 mm, and the opening diameter W8 was 2 mm in the CD direction and 1.5 mm in the MD direction. The depth H9 of the recess 91 was 6 mm, and the opening diameter W9 was 2 mm in the CD direction and 3 mm in the MD direction. The convex top portion 82T had a DTG / fiber input of 30% / min. The concave bottom portion 81B had a DTG / fiber input amount of 30% / min. Wall part 3 had a DTG / fiber input of 27% / min. The angle θ of the wall portion, the basis weight, the TiO ₂ ratio, the concealment rate, and the fineness were as shown in Table 1.
(Example 3)
The nonwoven fabric sample of Example 3 is the nonwoven fabric 10A shown in FIG. 3, and a thermoplastic fiber having a fineness of 2.5 dtex containing 0.15% by mass of TiO ₂ as a color-change material and a semi-dal nonwoven fabric by an air-through manufacturing method. Another semi-dal nonwoven fabric was made. Further, a fludal nonwoven fabric was prepared by an air-through manufacturing method using thermoplastic fibers having a fineness of 2.5 dtex containing 3% by mass of TiO ₂ as a color change material. A non-woven fabric having a basis weight, a TiO ₂ ratio, a concealment rate, and a fineness as shown in Table 1 by slitting a semi-dal non-woven fabric and a full-dal non-woven fabric and alternately laminating each of the slits on both sides of another semi-dal non-woven fabric and bonding them by air-through. 10A was produced. At that time, the semi-dal non-woven fabric and the full-dal non-woven fabric were arranged opposite to each other with another semi-dal non-woven fabric interposed therebetween.
Example 4
The non-woven fabric sample of Example 4 is the non-woven fabric 10B shown in FIG. 4, using a thermoplastic fiber having a fineness of 2.5 dtex containing 0.15% by mass of TiO ₂ as a color change material, and forming a semidal non-woven fabric by an air-through manufacturing method. Produced. Further, a fludal nonwoven fabric was prepared by an air-through manufacturing method using thermoplastic fibers having a fineness of 2.5 dtex containing 3% by mass of TiO ₂ as a color change material. The fludal nonwoven fabric was slit, and the fludal nonwoven fabric was spaced apart on both sides of the semidal nonwoven fabric. In that case, it arrange | positioned so that the recessed part between the fludal nonwoven fabric distribute | arranged to the other surface of a semidal nonwoven fabric may oppose the position where the fludal nonwoven fabric distribute | arranged to one side of a semidal nonwoven fabric opposes. That is, a full-dal nonwoven fabric was used as a convex portion, the convex portion and the concave portion were alternately arranged, and the full-dal nonwoven fabric and the concave portion were arranged facing each other across the semi-dal nonwoven fabric. After the arrangement as described above, the nonwoven fabric 10B having the wall angle θ, the basis weight, the TiO ₂ ratio, the concealment rate, and the fineness shown in Table 1 was manufactured by air-through bonding.
In the nonwoven fabric sample of Example 4, the depth of the concave portion 26 of the first surface layer 24 corresponding to the concave portion 81 of Example 1 was 6 mm, and the aperture diameter was 3 mm in the CD direction. Moreover, the depth of the recessed part 26 of the 2nd surface layer 25 corresponded to the recessed part 91 of Example 1 was 6 mm, and the aperture diameter was 3 mm in CD direction.
(Example 5)
The non-woven fabric sample of Example 5 is the non-woven fabric 10C shown in FIG. 5, using a thermoplastic fiber having a fineness of 2.5 dtex containing 0.15% by mass of TiO ₂ as a color change material, and separated from the non-woven fabric by an air-through manufacturing method. A non-woven fabric was prepared. And the nonwoven fabric was slit, it laminated | stacked on one side of another nonwoven fabric at intervals, and it was made to join by air through, and produced 10 C of nonwoven fabrics. Then, the titanium oxide (TiO ₂ ) of the color tone changing material 6 was applied to the produced nonwoven fabric sample so as to be 3% by mass using a spray paste, and the wall angle θ, the basis weight, and TiO shown in Table 1 were applied. _{It was set as} the nonwoven fabric sample of Example 5 which has ₂ ratio, a concealment rate, and a fineness.
In the nonwoven fabric sample of Example 5, the depth of the concave portion 29 on the one surface 10SA side corresponding to the concave portion 81 of Example 1 was 6 mm, and the aperture diameter was 3 mm in the CD direction.

(Comparative Example 1)
Using a thermoplastic fiber having a fineness of 2.5 dtex containing 3 wt% of titanium oxide (TiO ₂ ) as the color change material 6, a flat nonwoven fabric that does not form irregularities by an air-through manufacturing method was prepared, and a nonwoven fabric sample of Comparative Example 1 was obtained. . The nonwoven fabric sample had an overall thickness of 2.0 mm, a basis weight, a TiO ₂ ratio, a concealment rate, and a fineness as shown in Table 1.
(Comparative Example 2)
The surface sheet was peeled from Laurier F happy bare skin (trade name, manufactured by Kao Corporation 2016), and the peeled surface sheet was used as a nonwoven fabric sample of Comparative Example 2. The nonwoven fabric sample of Comparative Example 2 had an overall thickness of 2.2 mm, and the wall angle θ, the basis weight, the TiO ₂ ratio, the concealment rate, and the fineness were as shown in Table 1. In the nonwoven fabric sample of Comparative Example 2, the depth of the concave portion corresponding to the concave portion 81 of Example 1 was 1.5 mm, and the aperture diameter was 3 mm in the CD direction and 3 mm in the MD direction.
(Comparative Example 3)
A non-woven fabric sample of Comparative Example 3 was prepared by cutting circles with a radius of 3 mm on the flat non-woven fabric produced by the manufacturing method of Comparative Example 1 at intervals of 6 mm in the MD direction and 6 mm in the CD direction. The total thickness of the nonwoven fabric sample of Comparative Example 3 was 2.0 mm, and the basis weight, the TiO ₂ ratio, the concealment rate, and the fineness were flat nonwoven fabrics having openings as shown in Table 1. In the nonwoven fabric sample of Comparative Example 3, the depth of the aperture was measured as the depth of the recess corresponding to the recess 81 of Example 1, the value was 2 mm, the aperture diameter was 6 mm in the CD direction, and the MD direction 6 mm.
(Comparative Example 4)
The surface sheet was peeled off from Mooney Air Fit S size (trade name, manufactured by Unicharm Corporation 2016), and the peeled surface sheet was used as a nonwoven fabric sample of Comparative Example 4. The total thickness of the nonwoven fabric sample of Comparative Example 4 was 1.1 mm, and the wall angle θ, basis weight, TiO ₂ ratio, concealment rate, and fineness were as shown in Table 1. In the nonwoven fabric sample of Comparative Example 4, the depth of the concave portion corresponding to the concave portion 81 of Example 1 was 0.5 mm, and the aperture diameter was 2 mm in the CD direction.
(Comparative Example 5)
Pampers First surface of Pampers on the first skin S size (trade name, manufactured by The Procter End Gamble Company 2016) was peeled off, and the peeled surface sheet was used as a nonwoven fabric sample of Comparative Example 5. The total thickness of the nonwoven fabric sample of Comparative Example 5 was 0.5 mm, and the basis weight, the TiO ₂ ratio, the concealment rate, and the fineness were flat nonwoven fabrics having openings as shown in Table 1. In the nonwoven fabric sample of Comparative Example 5, the depth of the aperture was measured as the depth of the recess corresponding to the recess 81 of Example 1, the value was 0.5 mm, and the aperture diameter was 2 mm in the CD direction. It was 3 mm in the MD direction.

The hiding ratio (ΔE ^* _ab ) and the hiding ratio difference (E _β -E _α ) were determined for the above Examples and Comparative Examples.
Based on the above-described (concealment measurement method), imaging is performed with the optical axis L1 (see FIG. 2) of the imaging device tilted by 10 ° from 30 ° to 90 °, and L ^* a ^{* at} each angle ^. The three-dimensional orthogonal coordinates (L ^* , a ^* , b ^* ) of the b ^* color space were measured. The color difference between the measured value and the color coordinate of the white reference value was calculated as the concealment rate (ΔE ^* _ab ). Among contrast ratio (ΔE ^* _ab), and concealing property E _alpha results when viewed from the vertical direction (90 °), it was hiding E _beta when viewed from an oblique direction (80 ° ~30 °). It was determined as the difference between the difference between contrast ratio (E β -E _α). The results were as shown in Tables 1 and 2. Table 3 shows the relationship between the depth of the recess, the diameter of the hole, and the angle β.

As shown in Table 2, in Examples 1 to 5, when viewed from the vertical direction (90 °), the concealment ratio ΔE ^* _ab is lower than that of Comparative Examples 1 and 3 to 5, and is visually recognized in a state close to white. Therefore, the concealment was high. Further, in Examples 1 to 5, there is an angle in the viewing direction in which the difference in concealment ratio E _β -E _α is 0.5 or more in the CD direction at least in comparison with Comparative Examples 1 to 5, and the visibility in that angle is Was excellent. In particular, in Examples 1 and 2, the MD direction as well as the CD direction had a viewing angle with excellent visibility from an oblique direction. On the other hand, in Comparative Examples 1 to 5, the concealment rate from the oblique direction was lower than the value of the concealment rate from the vertical direction, and no visibility contrast was observed. In particular, Comparative Example 2 having a concavo-convex surface showed a low concealment rate at any angle viewpoint, and did not have a highly visible viewing angle. As described above, Examples 1 to 5 have the contradictory properties of hiding the colored object when viewed from the upper side in the vertical direction and the visibility of the colored object when viewed from the upper side in the oblique direction. It was.
In Examples 1, 2, 4, and 5, as shown in Table 3, β satisfying the relationship of the above-described mathematical formulas (R1), (R2), and (R3) is within 80 ° to 30 ° for the uneven surface. In Comparative Examples 2 to 5, β satisfying the above relationship did not exist within 80 ° to 30 °. In Examples 1, 2, 4 and 5, as shown in Tables 2 and 3, it was found that the combination of the depth of the recess, the hole diameter, and the viewing angle satisfying the above relational expression provides higher visibility contrast. . Specifically, as shown in Table 2, MD60 ° / CD60 ° in Example 1, MD60 ° / MD30 ° / CD60 ° in Example 2, CD60 ° / CD30 ° in Example 4, CD60 ° in Example 5・ Difference between the hiding ratio of the oblique viewpoint of CD30 ° and the hiding ratio of the vertical viewpoint was large.

3 Wall 10, 10A to 10D Nonwoven fabric 10SA One surface (first surface)
10SB The other side (second side)
26, 29 Concave part 28 Convex part 28A Convex top part 29A Concave bottom part 300 Colored object S Diagonal direction V Vertical direction

Claims (7)

Against one side of the nonwoven fabric, than concealing property for colored product in the case of viewing from the vertical direction upwards, e Bei the area concealing property is lowered for colored product in the case of viewing from an oblique direction upward,
The region has a convex top portion, a concave bottom portion, and an uneven surface including a wall portion connecting the convex top portion and the concave bottom portion, and the wall portion is made of constituent fibers rather than the convex top portion and the concave bottom portion. Nonwoven fabric with high fineness . The nonwoven fabric contains a color change material,
The wall portion, the Totsuitadaki portion and the than the concave bottom portion, the color tone content change material is less claim 1 Symbol placement of the nonwoven fabric. Against one side of the nonwoven fabric, than concealing property for colored product in the case of viewing from the vertical direction upwards, e Bei the area concealing property is lowered for colored product in the case of viewing from an oblique direction upward,
In the region, it has a concavo-convex surface having a convex top portion, a concave bottom portion, and a wall portion connecting the convex top portion and the concave bottom portion,
The nonwoven fabric contains a color change material,
The wall portion is a nonwoven fabric in which the content of the color change material is smaller than that of the convex top portion and the concave bottom portion . Concealing against a colored product in the case of visual observation from the oblique direction upward with respect to the wall portion, the Totsuitadaki portion and said vertical lower claim than hiding upward against colored product when visually from 1-3 with respect to the concave bottom portion The nonwoven fabric of any one of these . On one surface of the nonwoven fabric having the uneven surface, the wall portion is extended in a direction perpendicular to the one surface or opposite surfaces,
The nonwoven fabric according to any one of claims 1 to 4 , wherein a basis weight of the wall portion is smaller than a basis weight of the convex top portion and the concave bottom portion. An absorbent article using the nonwoven fabric according to any one of claims 1 to 5 .   An absorbent article using the nonwoven fabric according to any one of claims 1 to 5 as a surface sheet.