KR101862531B1 - Solid sheet and absorbent article in which same is used - Google Patents

Abstract

The three-dimensional sheet 10 includes a first fiber layer 11 having a first side 111 and a second side 112 and a second fiber layer 12 having a first side 121 and a second side 122, Respectively. Both layers are laminated so that the first surface 112 of the first fibrous layer and the first surface 121 of the second fibrous layer face each other. The three-dimensional sheet 10 has the first fibrous layer 11 protruding in the direction away from the second fibrous layer 12 to form a plurality of hollow convex portions 20. The first fibrous layer 11 and the second fibrous layer 12 are made of nonwoven fabric. The first fiber layer 11 includes a plurality of kinds of fibers. The plurality of kinds of fibers include at least two kinds of fibers composed of the first fiber and the second fiber. The first fiber and the second fiber each include a high melting point component and a low melting point component, and the diameters of the high melting point component and the low melting point component thereof are different.

Description

SOLID SHEET AND ABSORBENT ARTICLE IN WHICH SAME IS USED "

The present invention relates to a three-dimensional sheet. The present invention also relates to an absorbent article using the three-dimensional sheet.

A first aspect of the present invention is a three-dimensional sheet that can be used as a topsheet of an absorbent article such as a disposable diaper, wherein a first nonwoven fabric and a second nonwoven fabric are partially thermally fused to form a bonding portion, And a plurality of hollow convex portions protruding in a direction away from the second nonwoven fabric in the joint portion, the inside of which has hollow convex portions (see Patent Document 1). The convex portion in this three-dimensional sheet is of a hollow structure, and a three-dimensional sheet having a convex portion and a solid structure is also known (see Patent Document 2).

Apart from the techniques described in Patent Documents 1 and 2, the applicant of the present invention firstly comprises at least two kinds of thermally fusible fibers which are hardly fused to each other, the fibers of the same kind are stiffly fused at their intersections, And a nonwoven fabric in which the crossing points exist throughout (see Patent Document 3). This nonwoven fabric has good texture and excellent peel strength in the case where the convex member of the surface fastener is engaged, and even when peeled off after the convex member is engaged, the nonwoven fabric has little fuzziness, It is useful as a concave member of a face fastener and the like which can be engaged with each other.

Japanese Patent Application Laid-Open No. 2004-174234 Japanese Laid-Open Patent Publication No. 2006-175689 Japanese Patent Application Laid-Open No. 9-279467

The three-dimensional sheet described in Patent Documents 1 and 2 has a high cushion feeling due to its concavo-convex structure and exhibits a good texture. However, when the three-dimensional sheet is used, for example, as a topsheet of an absorbent article, there is room for improvement in terms of smoothness of the convex portion and low stimulus to the skin caused thereby. It was also found that there was room for improvement in terms of the standability of the convex portion and the difficulty of crushing the convex portion when the load was applied. On the other hand, the nonwoven fabric described in Patent Document 3 mainly assumes that it is used as a concave member of the surface fastener, and it is not assumed that the nonwoven fabric has a three-dimensional shape to enhance its cushioning feeling.

The present invention relates to an optical fiber having a first fiber layer having a first side and a second side opposite to the first side, and a second fiber layer having a first side and a second side opposite to the first side,

The second surface of the first fibrous layer and the first surface of the second fibrous layer are opposed to each other,

The first fiber layer and the second fiber layer are formed so as to protrude in the direction away from the second fibrous layer to form a plurality of convex portions,

The first fibrous layer and the second fibrous layer are both made of nonwoven fabric,

The first fiber layer includes a plurality of kinds of fibers,

Wherein the plurality of kinds of fibers comprise at least two types of fibers comprising a first fiber and a second fiber,

The first fiber and the second fiber each contain a high melting point component and a low melting point component,

Wherein the diameter ratio of the high melting point component and the low melting point component of the first fiber and the diameter ratio of the high melting point component and the low melting point component of the second fiber are different from each other.

Diameter ratio of the high melting point component and the low melting point component A _X = the diameter of the low melting point component of the Xth fiber D1 / the diameter of the high melting point component of the Xth fiber D2

The present invention further provides an absorbent article using the above-described three-dimensional sheet.

1 is a perspective view showing an embodiment of a three-dimensional sheet of the present invention.
Fig. 2 is a sectional view taken along the line II-II in Fig. 1. Fig.
3 is a schematic view showing an example of the cross-sectional structure of the first fiber or the second fiber used in the present invention.
Fig. 4 is a schematic view showing an apparatus preferably used for producing the three-dimensional sheet shown in Fig. 1. Fig.
Fig. 5 is a schematic diagram showing a state in which the sheet is formed in a concavo-convex shape using the apparatus shown in Fig.
Figs. 6 (a) and 6 (b) sequentially illustrate the steps of producing the three-dimensional sheet shown in Fig. 1 by using the apparatus shown in Fig. 4. Fig.
Fig. 7 (a) is a schematic view showing a method of determining a boundary when the first fiber layer of the three-dimensional sheet having a hollow convex portion has a clear difference visually on the first and second sides, and Fig. 7 b is a schematic view showing a method of determining a boundary when the first fiber layer of the three-dimensional sheet having the solid convex portion has a clear difference visually on the first surface side and the second surface side.
Fig. 8 (a) is a schematic view showing a method of determining a boundary when the first fiber layer of the three-dimensional sheet having hollow convex portions has no visually distinct difference between the first surface side and the second surface side, and Fig. 8 (b) is a schematic view showing a method of determining a boundary when the first fiber layer of the three-dimensional sheet having the solid convex portion has no visually distinct difference between the first surface side and the second surface side.
9 is a scanning electron microscope image of the three-dimensional sheet obtained in Example 7. Fig.
10 is a scanning electron microscope image of the three-dimensional sheet obtained in Comparative Example 2. Fig.

An object of the present invention is to improve the three-dimensional shape of a sheet, and more particularly, to provide a three-dimensional sheet having improved convexity smoothness while maintaining a cushioning feeling due to a three-dimensional shape. Another object of the present invention is to provide a three-dimensional sheet in which the uprightness of the convex portion and the difficulty of crushing of the convex portion when the load is applied are enhanced.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described with reference to the drawings based on preferred embodiments thereof. 1 is a perspective view of an embodiment of a three-dimensional sheet of the present invention. Fig. 2 is a sectional view taken along the line II-II in Fig. 1. Fig. The three-dimensional sheet 10 shown in these figures has an XY plane including a unidirectional X and a direction Y orthogonal thereto. The three-dimensional sheet 10 has a first fiber layer 11 and a second fiber layer 12 stacked on each other. The first fibrous layer 11 and the second fibrous layer 12 are in direct contact with each other and no other layer is interposed between the fibrous layers 11 and 12. [ The first fibrous layer 11 has a first side 111 and a second side 112 opposite to the first side. The second fibrous layer 12 has a first surface 121 and a second surface 122 facing it. The first fibrous layer 11 and the second fibrous layer 12 are laminated so that the first surface 112 of the first fibrous layer and the first surface 121 of the second fibrous layer face each other. The first fiber layer first surface 111 forms one surface of the three-dimensional sheet 10. On the other hand, the second fibrous layer second surface 122 forms the other surface of the three-dimensional sheet 10. Depending on the specific use of the three-dimensional sheet 10, one layer or two or more different layers may be laminated on the outer surface of the first surface 111 of the first fibrous layer. Similarly, one layer or two or more different layers may be laminated on the outer surface of the second fiber layer second surface 122.

The first fibrous layer 11 and the second fibrous layer 12 are partially bonded by thermal fusion, thereby forming a plurality of bonding portions 13. [ The first fibrous layer 11 protrudes in a direction away from the second fibrous layer 12 between the plurality of bonding portions 13 to form a large number of convex portions 20. The space between adjacent convex portions 20 is a concave portion 21. The bottom of the concave portion 21 includes the joining portion 13. Thereby, a concave-convex structure composed of the convex portion 20 and the concave portion 21 is formed on the first side 111 of the first fiber layer constituting one surface of the three-dimensional sheet 10. On the other hand, the side of the second surface 122 of the second fibrous layer constituting the other side of the three-dimensional sheet 10 is in a flat state.

The convex portion 20 of this embodiment is a hollow structure. Specifically, in the convex portion 20, a hollow space defined by the second surface 112 of the first fibrous layer 11 and the first surface 121 of the second fibrous layer 12 is formed therein have. On the other hand, in the concave portion 21, the first fibrous layer 11 and the second fibrous layer 12 are in close contact with each other, and a space is not substantially present between the both layers. The convex portion 20 in the three-dimensional sheet 10 of the present embodiment is not limited to a hollow structure and may be a solid structure in which the convex portion 20 is filled with fibers. Whether the convex portion 20 has a hollow structure or a solid structure can be determined by increasing the basis weight of the nonwoven fabric on the first fibrous layer 11 side or the nonwoven fabric on the second fibrous layer 12 side, 10, or by changing the concavo-convex shape of the gear portion in the first roll 31 provided in the manufacturing apparatus shown in Fig. 4, which will be described later, to be shallow. It is advantageous that the convex portion 20 has a hollow structure in view of the standability of the convex portion 20 and the difficulty of crushing the convex portion 20 when a load is applied.

In the XY plane, the convex portions 20 are arranged in a zigzag pattern. The concave portions 21 are also arranged in a zigzag pattern. The shapes and dimensions of the convex portions 20 are substantially the same. The same is true for the concave portions 21. The convex portion 20 has a substantially circular shape when viewed in plan view from the first fibrous layer 11 side of the three-dimensional sheet 10. The convex portion 20 has one portion (top portion) 201 in a substantially central portion of the convex portion 20 having a substantially circular shape in a plan view.

2, the first surface 111 of the first fiber layer 11 constituting the convex portion 20 is inclined with respect to the first surface 111 of the convex portion 20, And the second surface 112 have a convex curve protruding from the second fiber layer 12 side toward the first fiber layer 11 side. The shape of the convex curve has the same shape on an arbitrary section in the thickness direction Z passing through the portion 201. [ As described above, the convex portion 20 has a substantially hemispherical shell shape.

In the three-dimensional sheet 10 of the present embodiment, it is advantageous to control the bonding state of the constituent fibers contained in the three-dimensional sheet 10. As a result of the examination by the inventors of the present invention, it has been found that, by controlling the bonding state of the fibers, the three-dimensional sheet 10 is easy to be deformed in the XY plane in addition to the cushion feeling caused by the convex portions 20 . It has also been found that the standability of the convex portion 20 and the difficulty of crushing the convex portion 20 when the load is applied are improved. Due to these points, the convex portion 20 has good followability with respect to the movement of the object to which the convex portion 20 abuts, and the coefficient of friction is reduced. The lowering of the coefficient of friction is advantageous in that when the three-dimensional sheet 10 is used, for example, as a topsheet of an absorbent article, the irritation to the skin is reduced. As a result of further investigation by the present inventor in this respect, it has been found that the number S1 of fiber fusion points per fiber density on the first fiber layer first surface 111 side and the number of fiber fusion points per fiber density on the first fiber layer second surface 112 side The number of fiber fusion points per fiber density on the first face side 121 of the second fiber layer is P2 (number / length), P1 is P2 It is found that it is advantageous to manufacture the three-dimensional sheet 10 so as to be smaller.

In particular, P1 is preferably at least 55%, particularly preferably at least 65%, more preferably at most 95%, especially at most 85% of P2. Specifically, P1 is preferably 55% or more and 95% or less, particularly preferably 65% or more and 85% or less of P2.

The value of P1 itself is preferably at least 150 /,, particularly preferably at least 175/240, preferably at most 240 /,, particularly preferably at most 215 / P1. More specifically, it is preferable that P1 is 150 / ㎣ to 240 /,, especially 175/215 to 215 /.. The value of P2 itself is preferably 220 pieces / piece or more, especially 240 pieces / piece or more, more preferably 300 pieces / piece or less, especially 280 pieces / piece or less, Specifically, it is preferable that P2 is not less than 220/300 and not more than 300 /,, especially not less than 240/280 and not more than 280 /..

P1 and P2 are defined as the number of fiber fusion points per fiber density. In the conventional three-dimensional sheet of this type, for example, the three-dimensional sheet described in Patent Document 1, when the fiber density becomes high, The number was increasing. In contrast to this, in the three-dimensional sheet of the present embodiment, the number of fiber fusion points is smaller than that of the conventional three-dimensional sheet when they are compared at the same fiber density. In particular, the number of fiber fusion points on the first fiber layer second surface 112 is smaller than that of the conventional three-dimensional sheet. In the three-dimensional sheet of the present embodiment, P1 is smaller than P2, which means that the fusion score of the first fiber layer 11 is less than the fusion score of the second fiber layer 12. [ The smaller fusion splicing point means that the bonding points of the fibers are smaller. If the bonding points of the fibers are small, the degree of freedom of the fibers increases, and the fibers tend to move in the XY plane of the three-dimensional sheet 10. That is, in the three-dimensional sheet 10 of the present embodiment in which P1 is smaller than P2, the convex portion 20 is more likely to be deformed in the XY plane than the conventional three-dimensional sheet, and the convex portions 20 are in contact with each other The followability to the movement of the object becomes good. As a result, the effect of lowering the friction coefficient is efficiently expressed. As described above, in the three-dimensional sheet 10 of the present embodiment, the number of fiber fusion points is controlled so that desired characteristics are exhibited. Specific methods for controlling the number of fiber fusion points will be described later.

The fiber density as the basis of the calculation of P1 and P2 is the mass of the nonwoven fabric per unit volume. In the present invention, the unit of fiber density is / / ㎣. The fiber density on the first fiber layer first side 111 means the fiber density of the layer located on the side of the first fiber layer 11 when the first fiber layer 11 has a two-layer structure, In the case of a single-layer structure, the fiber density of a portion located on the side of the portion 201 when the thickness of the first fiber layer 11 is bisected. On the other hand, the fiber density on the first fiber layer second side 112 side is the fiber density of the layer located on the second fiber layer 12 side when the first fiber layer 11 has a two-layer structure, In the case where the first fiber layer 11 has a single-layer structure, it is a fiber density of a portion located on the second fiber layer 12 side when the thickness of the first fiber layer 11 is bisected. The fiber density on the first fiber layer side 121 side means a fiber density on the first fiber layer 11 side when the thickness of the second fiber layer 12 is bisected when the second fiber layer 12 has a single- Lt; / RTI > density. When the second fibrous layer 12 has a two-layer structure, it is the fiber density in the layer located on the first fibrous layer 11 side.

The boundary between the first and second fibrous layers 11 and 12 and the boundary between the first fibrous layer first surface 111 and the first fibrous layer second surface 112 , The fiber amount, the fiber diameter, the core / sheath ratio, the appearance (white), and the like are visually distinguished by visually observing the cross section of the nonwoven fabric with a microscope or an electron microscope (SEM). For example, when the three-dimensional sheet 10 to be provided for measurement contains fibers that contain titanium oxide and are whitened in appearance, and fibers that do not contain titanium oxide or have a low content and are not white In the case where there is a visually distinct difference as in the case, the surface to which each fiber layer with a visual difference is contacted is defined as a boundary, and is identified by the boundary. In the case where the three-dimensional sheet 10 has a fiber layer having a visually distinct difference, such as when the three-dimensional sheet 10 includes fibers having different fiber diameters or different fiber shapes, each fiber layer having the respective fiber diameters and shapes The surface to be touched is observed, and the surface is defined as a boundary and is identified by the boundary (see Figs. 7 (a) and 7 (b)). If there is no obvious difference in visually, the thickness of the nonwoven fabric is measured using a microscope (VHX-1000, manufactured by KYOSEN CO., LTD.), The thickness of the nonwoven fabric is divided into two equal parts, One side is the second layer. In this case, regarding the boundary between the first fiber layer first surface 111 and the first fiber layer second surface 112, when the convex portion 20 of the three-dimensional sheet 10 is hollow, as shown in Fig. 8 (a) As shown, the thickness of the first fiber layer 11 is divided into two equal parts. When the convex portion 20 is solid, as shown in Fig. 8 (b), the thickness between the portion 201 and the bottom portion of the concave portion 21 is divided into two equal parts.

Fiber density and number of fiber fusing points shall be prepared in the following order. That is, under the environment of 22 deg. C and 65% RH, the first surface 111, the first surface 112, and the first surface 121 of the second fibrous layer of the three-dimensional sheet 10 to be measured are measured with a sharp razor 1 mm in the direction of the machine direction of the three-dimensional sheet 10 and 1 mm in the direction of the machine direction of the three-dimensional sheet 10 are cut. Then, the measurement piece is cut out from two points per one sheet of the three-dimensional sheet 10, and this operation is performed on the five sheets of the three-dimensional sheet 10. The above-mentioned total of 10 measurement points are averaged to obtain the fiber density and the number of fiber fusion points.

Fiber density is measured by the following method. First, the cross section of the three-dimensional sheet 10 is cut, and the first surface of the first fibrous layer is measured for its thickness using a "microscope" (VHX-1000, manufactured by Keyens Corporation). Similarly, the thickness of the second surface of the first fibrous layer and the thickness of the second fibrous layer are measured. The apparent weight of each layer is measured, and the apparent weight / thickness is measured as the fiber density. The apparent weight of the first side of the first fibrous layer and the second side of the first fibrous layer is such that when the layer is clearly discernible, the first side of the first fibrous layer and the second side of the first fibrous layer Or the boundary is cut with a blade to measure the mass of the first surface of the first fibrous layer and the surface of the first surface of the first fibrous layer and then measure the mass of the first surface of the first fibrous layer and the surface of the first surface of the first fibrous layer The area is measured and calculated from their share. When the boundary of each layer can not visually distinguish a clear difference, the mass of the nonwoven fabric is measured without separating the layers, the area is measured, the basis weight of the entire nonwoven fabric is calculated from the quotients, Thereby obtaining the apparent weight of each layer.

The above-mentioned number of fiber fusion points is defined as the number of fusion points existing in the fiber when one fiber is focused on, and is defined as a point / number. The number of fiber fusion points is measured by the following method. First, the cut measuring piece is placed on an aluminum sample stand for a scanning electron microscope (SEM) on which a carbon tape is placed and fixed. Next, as shown in Fig. 9 and Fig. 10 to be described later, for example, an SEM image magnified approximately 140 to 150 times is obtained. From the obtained SEM image, the total number of the portions where the intersections of the fibers are thermally fused (circled portions in Figs. 9 and 10) are counted. On the basis of the SEM image, the fiber length as measured from the displayed fibers is measured. This operation is carried out from five SEM images. Further, an SEM image magnified approximately 35 times is obtained, and 50 pieces are extracted from the ends of the fibers, and the average fiber length is taken as one fiber length. The total fusing point in the screen of a 140-fold SEM image is divided by the total fiber length in the screen of the 140-times SEM image and multiplied by the length per one fiber of a 35-fold SEM image to measure the number of fusing points per fiber can do.

In the present invention, the mass per one fiber is defined as the mass of one fiber, in terms of one fiber, in [mu] / g. The mass per fiber is measured by the following method. First, the first surface 111 of the three-dimensional sheet 10 to be measured, the second surface 112 of the first fibrous layer and the first surface 121 of the second fibrous layer to be measured were measured with a sharp razor under the environment of 22 占 폚 and 65% And measuring the length from the end face to the end face of the fiber using a " microscope " (VHX-1000, manufactured by KEYENCE CORPORATION) do. Alternatively, after each nonwoven fabric is placed on a sample stand made of aluminum for a scanning electron microscope (SEM) on which a carbon tape is placed and fixed, the length from the end face to the end face of the fiber is measured using a scanning electron microscope, Measure the length. The cross-sectional area of the fibers (the cross-sectional area of each resin component in the fibers formed of a plurality of resins) is measured by using an electron microscope or the like and the cross-sectional shape of the fibers is measured by a differential scanning calorimeter (DSC) The type of resin is specified, the specific gravity is calculated, and the fineness is calculated. Using the thus obtained fineness and fiber length, the mass per one fiber of the three-dimensional sheet 10 is obtained.

The above-mentioned number of fiber fusion points is measured at each of the first fiber layer side 111 side, the first fiber layer second side 112 side, and the second fiber layer first side 121 side. By dividing the number of fiber fusion points F (points / pieces) by the mass per unit fiber (占 퐂 / piece) and then multiplying the fiber density? (占 퐂 / The number of fusing points (pieces / pieces) is calculated. In the first fiber layer 11, the number S1 of fiber fusion points per fiber density on the first fiber layer side 111 side and the number S1 of fiber fusion points per fiber density on the first fiber layer second side 112 side (S1 + S2) / 2, which is the average value of the number S2, and this value is defined as P1 described above.

It is advantageous to use specific fibers as the fibers constituting the first fiber layer 11 and the second fiber layer 12 in order to satisfy the relationship between P1 and P2 described above. Particularly, regarding the first fibrous layer 11, the first fibrous layer 11 has a multilayer structure including an upper layer on the first face side and a lower layer on the second face side, and the upper layer and one or both of the upper layer and the lower layer It is preferable that the fibers contain plural kinds of fibers. It is preferable that the plural kinds of fibers include at least two kinds of fibers composed of the first fiber and the second fiber. The first fiber and the second fiber preferably each include a high melting point component and a low melting point component having a melting point lower than that of the high melting point component. In this case, the high-melting-point component of the first fiber and the high-melting-point component of the second fiber may be of the same kind or may be of different kinds. The low melting point component of the first fiber and the low melting point component of the second fiber may be of the same kind or may be of different kinds. It is preferable that each of the first fiber and the second fiber contains a high melting point component and a low melting point component having a melting point lower than that of the high melting point component. This is because, by using a fiber containing a high melting point component, This is because the degree of fusion of the fibers is smaller than in the case of using the fibers containing the fibers. Details of this reason will be described later. The first fiber and the second fiber are distinguished by different diametric ratios. In the present specification, the diameter ratio is the ratio of the diameter of the high melting point component to the diameter (mu m) of the low melting point component of each of the first fiber and the second fiber. The diameter of the high melting point component and the diameter of the low melting point component are such that when the first and second fibers are core-sheath type composite fibers, the sheath resin is composed of a low melting point component and the core resin is composed of a high melting point component, In Fig. 3, D1 is the diameter of the low melting point component C1, and D2 is the diameter of the high melting point component C2. Then, the direct diameter ratio A _X of the high melting point component C 2 and the low melting point component C 1 of the Xth fiber is calculated from the following equation. Here, the " homogeneous heat-sealable fiber " means that the resin constituting the fiber is the same and the structure is the same. For example, when there are two core-sheath type conjugate fibers each comprising a high melting point component and a low melting point component, when the high melting point component and the low melting point component of these two resins are the same resin and the diameter ratio of the core sheath is the same, These two are heat-sealable fibers of the same kind. On the other hand, when the high-melting-point component and the low-melting-point component are the same resin, they are different kinds of heat-sealable fibers when the diameters are different. Incidentally, the term " including a plurality of kinds of fibers " means those containing different types of heat-sealable fibers.

Diameter ratio of the X-th fiber A _X = the diameter of the low melting point component of the X-th fiber D1 (占 퐉) / the diameter of the high melting point component of the X-

In the present invention, and it is the diameter ratio and the diameter ratio A ₁ A ₂ of the second fibers of the first fiber differently as described above. Ratio with a value of A ₂ / A ₁ of A ₂ to A ₁ is more preferably one that is preferable, and 0.99 is more preferable, and less than 0.91 or less than. The value of A ₂ / A ₁ is preferably 0.5 or more, more preferably 0.6 or more, and even more preferably 0.7 or more. By setting the ratios of A ₁ and A ₂ as described above, it is possible to easily control the above-described numbers of fiber fusing points P1 and P2. For example, the value of A ₂ / A ₁ is preferably 0.5 or more and less than 1, more preferably 0.6 or more and 0.99 or less, still more preferably 0.7 or more and 0.91 or less.

The ratio of the ratio A ₁ of the first fibers to the ratio A ₂ of the second fibers is as described above and the value of the diameter ratio A ₁ itself of the first fibers is preferably 1.1 or more and preferably 1.2 or more And more preferably 1.3 or more. Further, it is preferably 2.0 or less, more preferably 1.9 or less, and further preferably 1.8 or less. Specifically, the value of the direct diameter ratio A ₁ itself of the first fiber is preferably 1.1 or more and 2.0 or less, more preferably 1.2 or more and 1.9 or less, still more preferably 1.3 or more and 1.8 or less.

On the other hand, the value of the direct diameter ratio A ₂ itself of the second fiber is preferably 1.1 or more, more preferably 1.2 or more, further preferably 1.3 or more, provided that it is smaller than A ₁ . Further, it is preferably 2.0 or less, more preferably 1.9 or less, and further preferably 1.8 or less. Specifically, the value of the diameter ratio A ₂ itself of the second fiber is preferably 1.1 or more and 2.0 or less, more preferably 1.2 or more and 1.9 or less, still more preferably 1.3 or more and 1.8 or less.

By controlling the diameter ratio A ₁ of the first fiber and the diameter ratio A ₂ of the second fiber, the number of fiber fusion points P1 and P2 can be easily controlled. For example, a first X fibers are core-sheath type composite fibers, the sheath resin is made of a low-melting component, the core when the resin and consisting of a melting component, direct when expenses A _X is smaller, the volume of the volume of the sheath resin core resin , The sheath resin is liable to be stretched at the time of melt spinning, so that the orientation of the polymer chain is enhanced and the crystallization proceeds. As a result, the softening point of the sheath resin on the surface of the fiber, that is, the surface of the sheath resin and in the vicinity thereof is increased. On the other hand, when the diameter ratio A _X is large, the volume of the sheath resin becomes close to the volume of the core resin, so that the extent of drawing of the sheath resin during melt spinning is lower than when the diameter ratio A _X is small. As a result, when the diameter ratio A _X is large, the orientation of the polymer chain is relatively lowered and the degree of crystallization is relatively lower compared to when the diameter ratio A _X is small. As a result, when the diameter ratio A _X is large, the softening point of the sheath resin on the fiber surface, that is, on the surface of the sheath resin and in the vicinity thereof is relatively low as compared with when the diameter ratio A _X is small. A diameter ratio _X is smaller the higher the softening point of the X of the fiber surface, fiber fusion point P1 of the first fiber layer, which contains a lot of the diameter ratio _X A is smaller than the X textile fiber layer 2 is smaller than P2. As described above, the softening point of the surface of the X-th fiber varies in accordance with the magnitude of the diameter ratio A _X , and the degree of fusion of the fibers differs due to the change of the softening point, so that the numbers P1 and P2 of fiber fusion points can be controlled.

The inventors of the present invention have considered the reason why the softening point of the sheath resin becomes high when the ratio A _x is small, in detail as follows. For example, if the fibers, and the sheath resin composed of a low melting point component, and the core-sheath type composite fibers comprising a core resin made of a melting component, in the production of the core-sheath type composite fiber by a melt spinning method, the diameter ratio A _X If the diameter ratio A _X is smaller than when it is large, the second component solidifies more quickly than the core component. As a result, the spinning tension during melt spinning is likely to concentrate on the sheath resin, and the sheath resin is liable to be further stretched due to this. By this stretching, the orientation of the polymer chain is enhanced and crystallization proceeds. Increasing the orientation of the polymer chain of the sheath resin results in an increase in the softening point of the sheath resin. Further, the progress of the crystallization of the polymer chain of the sheath resin results in an increase in the heat of fusion of the crystal. As a result of these results, fibers having a small diameter ratio A _X are hardly fused and the number of fiber fusion points is reduced. Further, the core-sheath type conjugate fiber having a small diameter ratio A _X tends to be thread-broken during melt spinning and is not used so far because it is difficult to spin.

The rise of the softening point and the increase of the heat of fusion are more remarkable by cutting the core-sheath type conjugate fibers obtained by melt spinning and forming them into short fibers and appropriately adjusting the conditions for storing the short fibers. . Concretely, it is advantageous to set the temperature at the time of storage at 105 ° C or higher and 120 ° C or lower which is higher than usual. It is advantageous to set the storage time to 1 hour to 3 hours, which is longer than usual, provided that the storage temperature is within this range. In short, it is advantageous to store at a higher temperature than usual and for a long time. The annealing effect of the crystallized sheath resin is expected by such storage at a high temperature and for a long time. By the annealing, the crystallization of the sheath resin is further promoted.

The thermal properties of the inventors, diameter ratio A _X = 1.6 core-sheath type composite fiber A, and a small diameter ratio A _X would A _X = 1.2 core-sheath type on a composite fiber B, the second component than that of a differential scanning calorimeter As a result of the measurement, the results shown in Table 1 below were obtained. The core-sheath type conjugate fibers A and B are all polyethylene terephthalate, polyethylene terephthalate, and a fineness of 2.3 dtex. The core-sheath type composite fiber A was made into a single fiber and then stored at 100 占 폚 for 30 minutes. The core-sheath type conjugate fiber B was made into a single fiber and then stored at 120 DEG C for 2 hours. As is clear from the results shown in the table, the core-sheath type conjugate fiber B having a small diameter ratio A _X has a high endothermic peak of supercritical fluid and a high softening point. It can also be seen that the core-sheath type conjugate fiber B having a small diameter ratio A _X has a large heat of fusion and crystallization of polyethylene is proceeding.

The softening point of the resin on the surface of the first fiber and the second fiber can be measured by nano thermal annihilation (nanoTA). In nanoTA, an atomic force microscope (AFM) image of a sample is obtained with a cantilever having a heating mechanism, and then the target point is heated. When the sample is softened with heating, the cantilever intrudes into the sample. By detecting the displacement of the cantilever, the softening point of the microscopic region of the sample is measured. If the first fiber and the second fiber are selected so that the difference between the softening point S1 of the resin on the surface of the first fiber measured by this method and the softening point S2 of the resin on the surface of the second fiber is within a specific range, The numbers P1 and P2 can be easily controlled.

It is preferable that the first fiber layer 11 has a multilayer structure including an upper layer on the first face side and a lower layer on the second face side and one or both of the upper layer and the lower layer thereof include at least the first fiber and the second fiber Preferably, as described above, in the first fiber layer 11, the first heat-sealable fiber is contained as the first fiber and the second heat-sealable fiber is contained as the second fiber. It is more preferable to contain fibers of the species. As the first heat-sealable fiber and the second heat-sealable fiber, it is preferable to use a core-sheath type heat-sealable fiber. It is preferable that the first heat-sealable fiber and the second heat-sealable fiber are different in the resin of the superfine component, and they are different in kind. Or the first thermofusible fiber and the second thermofusible fiber have the same core and subcomponent resin and different volume proportions of core and subcomponent resin and are preferably of different types. By using two types of heat-sealable fibers of different types, the ease of fusion between fibers differs depending on the combination of fibers, and accordingly, the number of fiber fusion points can be controlled. The volume ratio can be changed to the area ratio of the core component and the sub component in the cross section of the fiber.

When the heat-sealable fiber having a volume ratio of the seam component and the sheath component is different between the first fiber and the second fiber, the ratio of the volume V1 of the superfine component to the volume V2 of the core component in the heat- , The ratio V2 / V1 is preferably 0.35 or more, more preferably 0.6 or more, and even more preferably 0.8 or more. Further, it is preferably 6.0 or less, more preferably 4.0 or less, and further preferably 2.5 or less. Concretely, V2 / V1 is preferably 0.35 or more and 6.0 or less, more preferably 0.6 or more and 4.0 or less, still more preferably 0.8 or more and 2.5 or less. The volume ratio of the core component of the X-th fiber to the resin of the second component can be changed to the area ratio of the core component and the sub component in the cross section of the fiber. The volume ratio V2 / V1 of the core component of the X-th fiber and the resin of the supercritical component is proportional to the diameter ratio D2 of the core component composed of the high melting point component and the diameter ratio D1 / D1 of the diameter D1 of the secondary component composed of the low melting point component. In other words, it is inversely proportional to the diameter ratio A _X of the _X -th fiber. The larger V2 / V1 is equivalent to the smaller diameter ratio A _X. The smaller the diameter ratio A _X is, the higher the softening point of the surface of the X-th fiber is. Thus, the fiber fusion point P1 of the first fibrous layer comprising a lot of smaller diameter ratio A _X is the X fiber than the second fiber layer is smaller than P2. The heat-sealable fiber may be concentric core-sheath type conjugated fiber, eccentric type core-sheath type conjugated fiber, side-by-side type conjugated fiber, or the like.

As the first fiber and the second fiber, various ones can be used. For example, as described above, the second heat-sealable fiber is contained as the second fiber, the second heat-sealable fiber is the core-sheath type heat-sealable fiber, and the sheath resin Having a low melting point component and the core resin having a high melting point component can be used. In this case, it is preferable that the second heat-sealable fiber is included at least on the side of the first surface 112 of the first fiber layer.

Or a second heat-sealable fiber as the second fiber, the second heat-sealable fiber is a core-sheath type heat-sealable fiber, and the sheath resin of the second heat-sealable fiber is a low- A polypropylene having a melting point can be used. In this case, it is preferable that the second heat-sealable fiber is included at least on the side of the first surface 112 of the first fiber layer.

The second heat-sealable fiber is a core-sheath type heat-sealable fiber, and the sheath resin in the second heat-sealable fiber is made of a polyethylene resin , And a core resin made of a resin having a melting point higher than that of polyethylene. In this case as well, it is preferable that the second heat-sealable fiber is included at least on the side of the first fiber layer second surface 112.

In particular, as at least one of the first heat-sealable fiber and the second heat-sealable fiber, a fiber having a core-sheath structure having a low melting point polypropylene as a super component, a fiber having a core- And a fiber having a core-sheath structure having a polyester as a supercontent are preferably used. It is preferable that these fibers are included at least on the side of the first fiber layer second surface 112. The first heat-sealable fiber and the second heat-sealable fiber may be concentric core-sheath type conjugated fiber, eccentric type core-sheath type conjugated fiber, and side by side type conjugated fiber.

When a fiber having a core-sheath structure having a low melting point polypropylene as a first component is used as the first heat-fusible fiber, a fiber having a core-sheath structure consisting of polyethylene as the second heat-fusible fiber and a low- Fiber having a core-sheath structure having a fiber as a second component. In particular, in order to impart sealing property and strength to the obtained nonwoven fabric as the first heat-sealable fiber, a fiber having a core-sheath structure having a low melting point polypropylene as a supercritical component is used, and a second heat- , It is preferable to use a fiber having a core-sheath structure consisting of polyethylene as a sub component in order to impart a good texture and strength to the obtained non-woven fabric. It is preferable that the first heat-sealable fiber and the second heat-sealable fiber are included at least on the side of the first surface 112 of the first fiber layer.

As the low melting point polypropylene used as a superfine component in the fibers having a core-sheath structure having the low melting point polypropylene as a super component, known low melting point polypropylene is used without particular limitation, but its melting point is from 130 DEG C to 150 DEG C Or less. Examples of the core component include polyethylene terephthalate (melting point: 250 ° C or more and 270 ° C or less), polypropylene (melting point: 150 ° C or more and 170 ° C or less) and the like. The ratio of the supercritical component to the deep component is preferably 20 vol% or more, more preferably 30 vol% or more. Further, it is preferable that the supercritical component is 80 vol% or less, more preferably 70 vol% or less. Specifically, the supercritical component is preferably 20 vol% or more and 80 vol% or less, more preferably 30 vol% or more and 70 vol% or less. The core component is preferably 50 vol% or more, and more preferably 60 vol% or more. Further, it is preferably 80 vol% or less, more preferably 70 vol% or less. Concretely, the volume ratio is preferably 50 vol% or more and 80 vol% or less, more preferably 60 vol% or more and 70 vol% or less.

As the polyethylene used as a superfine component in the fibers having a core-sheath structure comprising the polyethylene as a supercontent, it is preferable to use a polyethylene having a melting point of 120 ° C or more and 140 ° C or less. Examples of the core component include polyethylene terephthalate having a melting point of 250 DEG C or more and 270 DEG C or less, and polypropylene having a melting point of 150 DEG C or more and 170 DEG C or less. The ratio of the supercritical component to the deep component is preferably 15 vol% or more, more preferably 23 vol% or more. It is preferable that the supercritical component is 75 vol% or less, more preferably 61 vol% or less. Specifically, the supercritical component is preferably 15 vol% or more and 75 vol% or less, more preferably 23 vol% or more and 75 vol% or less. The core component is preferably 49 vol% or more, and more preferably 59 vol% or more. The core component is preferably 85% by volume or less, more preferably 77% by volume or less. Concretely, it is preferable to set the padding component at 49 vol% or more and 85 vol% or less, more preferably 59 vol% or more and 77 vol% or less.

The low-melting-point polyester used as a super-component in the fibers having a core-sheath structure having the low-melting-point polyester as a super-component may be any low-melting-point polyester and can be used without particular limitation. Or less. Examples of the core component include polyethylene terephthalate having a melting point of 250 DEG C or more and 270 DEG C or less, and polypropylene having a melting point of 150 DEG C or more and 170 DEG C or less. The ratio of the supercritical component to the deep component is preferably 20 vol% or more, more preferably 30 vol% or more. Further, it is preferable that the supercritical component is 80 vol% or less, more preferably 70 vol% or less. Specifically, the supercritical component is preferably 20 vol% or more and 80 vol% or less, more preferably 30 vol% or more and 70 vol% or less. The core component is preferably 50 vol% or more, and more preferably 60 vol% or more. The core component is preferably 80 vol% or less, more preferably 70 vol% or less. Specifically, it is preferable that the core component is 50 vol% or more and 80 vol% or less, more preferably 60 vol% or more and 70 vol% or less.

The thickness (fineness) of the first heat-sealable fiber and the second heat-sealable fiber may be the same or different, preferably 1 dtex or more, more preferably 2 dtex or more, and particularly preferably 3 dtex or more. More preferably 15 dtex or less, further preferably 10 dtex or less, and particularly preferably 6 dtex or less. Specifically, it is preferably 1 dtex or more and 15 dtex or less, more preferably 2 dtex or more and 10 dtex or less, particularly preferably 3 dtex or more and 6 dtex or less. The first heat-sealable fiber and the second heat-sealable fiber used as the first fiber and the second fiber may be continuous fibers made of long fiber filaments or staple fibers such as staple fibers. When short fibers are used, the lengths of the first fiber and the second fiber may be the same or different. Concretely, it is preferable that the lengths of the first fibers and the second fibers are each independently not less than 35 mm and not more than 70 mm. The use of a short fiber as the first fiber and / or the second fiber is preferable because the three-dimensional sheet 10 can be easily produced according to a production method described later.

The mixing ratio of the first heat-sealable fiber to the second heat-sealable fiber is arbitrary depending on the fiber used, but when the total amount of the first heat-sealable fiber and the second heat-sealable fiber is 100 parts by mass The first heat-sealable fiber is preferably 10 parts by mass or more and 70 parts by mass or less. More specifically, it is preferable that a fiber having a core-sheath structure having the low-melting point polypropylene as a super-component is used as the first heat-sealable fiber, and a fiber having a core-sheath structure using polyethylene as the second heat- , It is preferable that the first heat-sealable fiber is 10 parts by mass or more and 70 parts by mass or less when the total amount of the first heat-sealable fiber and the second heat-sealable fiber is 100 parts by mass.

The first heat-sealable fiber and the second heat-sealable fiber may be included in the first fiber layer 11 of a single layer structure or may be included in the first fiber layer 11 of a multilayer structure such as a two-layer structure. In the latter case, an upper layer positioned on the first fiber layer first surface 111 side and a lower layer positioned on the first fiber layer second surface 112 side are provided with a first thermally fusible fiber and a second thermally meltable If fibers are included, the relationship between P1 and P2 is more easily satisfied.

When the first fibrous layer 11 has a two-layer structure of an upper layer located on the first fibrous layer first side 111 side and a lower layer positioned on the first fibrous layer second surface 112 side, In the fibrous layer 11, it is preferable that the number S2 of fiber fusion points per fiber density on the second surface 112 side is smaller than the number S1 of fiber fusion points per fiber density on the first surface 111 side . Even if S1 and S2 have such a relationship, the relationship between P1 and P2 is more easily satisfied. In particular, S1 is preferably more than 100%, particularly preferably not less than 105%, more preferably not more than 300%, more preferably not more than 125%. Specifically, it is preferable that S1 is more than 100% but not more than 300%, particularly not less than 105% and not more than 125% of S2. In order to achieve such a relationship, it is preferable to use two or more of the above-mentioned core-sheath type thermally fusible fibers as the thermally fusible fibers contained in the lower layer positioned on the side of the first fiber layer second surface 112 desirable.

When the first fibrous layer 11 has a two-layer structure of a lower layer positioned on the first fibrous layer first surface 111 side and a first fibrous layer second surface 112 side, It is preferable that the heat-sealable fiber of the same kind is included in the heat-sealable fiber. As a result, the adhesion between the upper layer and the lower layer is improved, and the mechanical strength of the three-dimensional sheet 10 is increased.

When the first fibrous layer 11 has a two-layer structure of an upper layer located on the first fibrous layer first surface 111 side and a lower layer positioned on the first fibrous layer second surface 112 side, It is preferable that it is composed of only one heat-sealable fiber. By doing so, it is possible to effectively suppress the fuzziness on the first fiber layer side 111 side. In this case, it is preferable that the lower layer contains plural kinds of fibers, and it is more preferable that plural kinds of heat-sealable fibers are included. The plurality of kinds of heat-sealable fibers may include the first heat-sealable fiber as one kind or may not include the first heat-sealable fiber. In particular, it is preferable that the upper layer comprises only the first heat-sealable fiber and the lower layer contains the first heat-sealable fiber and the second heat-sealable fiber. By doing so, it is preferable that the upper layer and the lower layer are less likely to be peeled off when a rubbing or an external force is applied at the time of use, thereby improving the appearance after use.

As for the second fibrous layer 12, it is preferable that the second fibrous layer 12 and the first fibrous layer 11 include the same kind of heat-sealable fibers. By doing so, the bonding strength between the first fibrous layer 11 and the second fibrous layer 12 in the concave portion 21 of the nonwoven fabric 10 can be further enhanced. The improvement of the bonding strength in the concave portion 21 contributes to suppressing the fuzziness on the first fiber layer side 111 side. The heat-sealable fiber contained in the lower layer positioned on the second surface 112 side of the first fiber layer 11 and the heat-sealable fiber contained in the second fiber layer 12 are made of the same kind .

For the same reason, it is also preferable that the second fiber layer 12 includes the first heat-sealable fiber. Particularly, the second fiber layer 12 includes the first heat-sealable fiber, and the lower layer positioned on the second surface 112 side of the first fiber layer 11 preferably includes the first heat-sealable fiber Do.

The first fibrous layer 11 and the second fibrous layer 12 in the three-dimensional sheet 10 can be made of nonwoven fabric, for example. The first fibrous layer 11 may have a single-layer structure or a multi-layer structure. From the viewpoint of the degree of freedom of selection of fibers to be blended into the first fiber layer 11, it is preferable that the first fiber layer has a multilayer structure. The second fibrous layer 12 may have a single-layer structure or a multi-layer structure. Examples of the nonwoven fabric include a spunbonded nonwoven fabric, an air-through nonwoven fabric, a spunlaced nonwoven fabric, a meltblown nonwoven fabric, a resin-bonded nonwoven fabric, and a needle punch nonwoven fabric. The same kind of nonwoven fabric may be used for the first fiber layer 11 and the second fiber layer 12, or a different kind of nonwoven fabric may be used.

The basis weight of the first fibrous layer 11 and the second fibrous layer 12 can be appropriately set in accordance with the specific use of the three-dimensional sheet 10. For example, when the three-dimensional sheet 10 is used as the topsheet of the absorbent article, the basis weight of the first fibrous layer 11 and the second fibrous layer 12 is independently 3 g / m 2 or more, particularly 5 g / M < 2 > or more, preferably 30 g / m < 2 > or less, and particularly preferably 15 g / m & Specifically, it is preferable to set it to 3 g / m 2 or more and 30 g / m 2 or less, particularly 5 g / m 2 or more and 15 g / m 2 or less.

The basis weight of the three-dimensional sheet 10 including the first fibrous layer 11 and the second fibrous layer 12 can be appropriately set according to the specific use thereof. For example, when the three-dimensional sheet 10 is used as the topsheet of the absorbent article, the basis weight of the three-dimensional sheet 10 is preferably not less than 6 g / m 2, particularly preferably not less than 10 g / M 2 or less, particularly preferably 30 g / m 2 or less. Specifically, it is preferable to set it to 6 g / m 2 or more and 60 g / m 2 or less, particularly 10 g / m 2 or more and 30 g / m 2 or less.

The thickness of the three-dimensional sheet 10 can be appropriately set in accordance with its specific use. For example, when the three-dimensional sheet 10 is used as the topsheet of the absorbent article, the thickness of the three-dimensional sheet 10 is preferably at least 0.1 mm, particularly at least 0.2 mm, mm or less. Concretely, it is preferable that the thickness is 0.1 mm or more and 5.0 mm or less, particularly 0.2 mm or more and 3.0 mm or less. The thickness of the three-dimensional sheet 10 is the thickness at the largest thickness of the three-dimensional sheet 10. The portion having the largest thickness is generally located at the center of the convex portion 20. [ The thickness is measured in the following manner. That is, first, the three-dimensional sheet 10 to be measured is cut at a length of 50 mm and a width of 50 mm to prepare a cut piece of the three-dimensional sheet 10. The thickness of this cutting piece is measured under a pressure of 49 Pa. The measurement environment shall be a temperature of 20 ± 2 ℃ and a relative humidity of 65 ± 5%. A microscope (VHX-1000, manufactured by KEYENCE CORPORATION) is used for the measurement apparatus. First, an enlarged photograph of the cut piece is obtained. In the enlargement, insert what is known dimensions at the same time. The thickness of the three-dimensional sheet 10 is measured by adjusting the scale of the cut piece. The above operation is carried out three times, and the average value of three times is set as the thickness [mm] of the three-dimensional sheet 10 in a dry state.

Next, a preferable manufacturing method of the three-dimensional sheet 10 of the present embodiment will be described. As shown in Fig. 4, the method for manufacturing the three-dimensional sheet 10 according to the present embodiment includes a first roll 31 having a concavo-convex shape on its circumferential surface, a concave- The first fiber sheet 11a is engaged with the engaging portion of the second roll 32 having the shape of the circumferential surface to form the concave and convex portions of the second fiber sheet 12a, And a step of joining the first fiber sheet 11a located on the convex portion 31a with the heat roll 34. [ The first fibrous sheet 11a is a raw material of the first fibrous layer 11 in the intended three-dimensional sheet 10. The second fibrous sheet 12a is a raw sheet of the second fibrous layer 12 in the intended three-dimensional sheet 10. The first fiber sheet 11a may have a single-layer structure or a multi-layer structure. Similarly, the second fiber sheet 12a may have a single-layer structure or may have a multi-layer structure. Regarding the manufacturing method of the present embodiment, the point that is not specifically explained is carried out in the same manner as the method described in Japanese Laid-Open Patent Publication No. 2004-174234 (particularly the method described in paragraphs [0021] to [0025]) .

5 shows a state in which the first fibrous sheet 11a is engaged with the engaging portion of the first roll 31 and the second roll 32 and the sheet 11a is concave and convex. The first fibrous sheet 11a introduced between the both rolls 31 and 32 in the engaged state is positioned between the convex portion 31a of the first roll 31 and the convex portion 31a of the second roll 32 32a, so that the first fiber sheet 11a is concavo-convex. As the first fiber sheet 11a, it is preferable to use, for example, a nonwoven fabric. An example of such a nonwoven fabric is as described above. The first fiber sheet 11a preferably contains the first heat-sealable fiber and the second heat-sealable fiber described above. Particularly, the first fibrous sheet 11a has a two-layer structure, and in the lower layer corresponding to the second surface side of the first fibrous layer 11 among the two-layer structure, the first heat- It is preferable that the second heat-sealable fiber is contained. The first fibrous sheet 11a has a two-layer structure. Of the two-layer structure, the upper layer corresponding to the first surface side of the first fibrous layer 11 and the upper layer corresponding to the first fibrous layer 11 It is also preferable that each of the lower layers corresponding to the two face sides contains the same kinds of heat-sealable fibers.

In the uneven shape shown in Fig. 5, the respective surfaces of the first fiber sheet 11a are in a substantially parallel state. The concave-convex first fiber sheet 11a is then joined to the second fiber sheet. The joint 13 is formed by this joining. The sectional shape of the sheet immediately after bonding is shown in Fig. 6 (a). As shown in the figure, the first fiber sheet 11a in the sheet immediately after the bonding is generally parallel to each side.

Thus, the intended three-dimensional sheet 10 is obtained. The obtained three-dimensional sheet 10 has a surface sheet positioned on the side closer to the wearer's skin at the time of wearing, a back sheet positioned farther from the wearer's skin at the time of wearing, and a liquid- It is preferably used as the surface sheet of the absorbent article. Alternatively, the three-dimensional sheet 10 may be used as a sheet disposed between the topsheet and the absorbent body, a sheet for forming a perforated cuff, and particularly, a sheet forming an inner wall of a perforated cuff. When the nonwoven fabric 10 is used as the topsheet of the absorbent article, it is preferable to dispose the first fibrous layer 11 of the nonwoven fabric 10 so as to face the wearer's skin. Specific examples of the absorbent article using the nonwoven fabric 10 include disposable diapers, sanitary napkins, incontinence pads, panty liners, and the like.

While the present invention has been described based on the preferred embodiments thereof, the present invention is not limited to the above embodiments. For example, in the above-described embodiment, the convex portion of the three-dimensional sheet 10 has a substantially hemispheric shape. Alternatively, the convex portion of the three-dimensional sheet 10 may have a substantially rectangular shape as described in Patent Document 1, for example.

With respect to the above-described embodiment, the present invention further discloses the following three-dimensional sheet, the topsheet of the absorbent article, and the absorbent article.

<1>

A first fiber layer having a first side and a second side opposite to the first side, and a second fiber layer having a first side and a second side opposite to the first side,

The second surface of the first fibrous layer and the first surface of the second fibrous layer are opposed to each other,

The first fibrous layer and the second fibrous layer are partially thermally fused to form a joint portion and the first fibrous layer protrudes in a direction away from the second fibrous layer between the abutting portions to form a plurality of convex portions,

The first fibrous layer and the second fibrous layer are both made of nonwoven fabric,

The first fiber layer includes a plurality of kinds of fibers,

Wherein the plurality of kinds of fibers comprise at least two types of fibers comprising a first fiber and a second fiber,

The first fiber and the second fiber each contain a high melting point component and a low melting point component,

Wherein the diameter ratio of the high melting point component and the low melting point component of the first fiber and the diameter ratio of the high melting point component and the low melting point component of the second fiber are different from each other.

Diameter ratio of the high melting point component and the low melting point component A _X = the diameter of the low melting point component of the Xth fiber D1 / the diameter of the high melting point component of the Xth fiber D2

&Lt; 2 &

The staple sheet according to the above-mentioned &lt; 1 &gt;, wherein the first fibrous layer has a multilayer structure including an upper layer on the first surface side and a lower layer on the second surface side and one or both of the upper layer and the lower layer thereof include plural kinds of fibers .

&Lt; 3 &

That the proportion of the value of A ₂ / A ₁ of A ₂ to A ₁ is less than 1, and preferably, 0.99 or less is more preferable, and 0.91 is even more preferable less than or equal to the <1> or a three-dimensional sheet according to <2>.

&Lt; 4 &

The three-dimensional sheet according to any one of the above items <1> to <3>, wherein the value of A ₂ / A ₁ is preferably 0.5 or more, more preferably 0.6 or more, and further preferably 0.7 or more.

&Lt; 5 &

The dimensional sheet A ₁ of the first fiber preferably has a value of 1.1 or more, more preferably 1.2 or more, and more preferably 1.3 or more, according to any one of the items <1> to <4>.

&Lt; 6 &

The three-dimensional sheet according to any one of the above items <1> to <5>, wherein the value of the diameter ratio A ₁ of the first fiber is preferably 2.0 or less, more preferably 1.9 or less, further preferably 1.8 or less.

&Lt; 7 &

Straight-value of the guard A ₂ of the second fiber, and smaller than A ₁ under the conditions, 1.1 a which of preferred, and 1.2 even be not less than and more preferably, to 1.3 or more preferable the <1> to <6> or more Dimensional sheet.

&Lt; 8 &

The value of the diameter ratio A ₂ of the second fiber is, A _1, A than any of the subject is smaller, and it is 2.0 or less, 1.9 or less is more preferred, and preferred above <1> further to 1.8 or less to <7> Dimensional sheet.

&Lt; 9 &

The three-dimensional sheet according to any one of the above-mentioned &lt; 1 &gt; to &lt; 8 &gt;, wherein the first fiber layer and the second fiber layer contain the same kind of heat-sealable fibers.

&Lt; 10 &

The three-dimensional sheet according to any one of &lt; 1 &gt; to &lt; 9 &gt;, wherein the first side of the first fibrous layer comprises a first fiber and a second fiber.

&Lt; 11 &

Wherein the first fiber layer comprises a plurality of kinds of fibers having a first fiber and a second fiber, the first fiber includes a first heat-sealable fiber,

The three-dimensional sheet according to any one of <1> to <10>, wherein the second fiber layer also includes the first heat-sealable fiber.

&Lt; 12 &

The three-dimensional sheet according to any one of the above-mentioned <1> to <11>, wherein the same kind of heat-sealable fiber is contained in the upper layer on the first face side and the lower layer on the second face side of the first fiber layer.

&Lt; 13 &

Wherein the first fiber layer comprises a plurality of kinds of fibers having a first fiber and a second fiber, the first fiber includes a first heat-sealable fiber,

The three-dimensional sheet according to any one of the above items <1> to <12>, wherein the first fiber layer has a two-layer structure and the upper layer on the first surface side of the first fiber layer comprises only the first heat-sealable fiber.

&Lt; 14 &

The three-dimensional sheet according to <11> or <13>, wherein the second fiber is made of short fibers.

<15>

And a second heat-sealable fiber as a second fiber,

The three-dimensional sheet according to any one of the above-mentioned &lt; 1 &gt; to &lt; 14 &gt;, wherein the second heat-sealable fiber is contained at least on the second surface side of the first fiber layer.

&Lt; 16 &

Wherein the plurality of kinds of fibers have a first fiber and a second fiber, the second fiber includes a second heat-sealable fiber,

The stator sheet according to any one of the above items <1> to <15>, wherein the second heat-sealable fiber is a core-sheath type heat-sealable fiber wherein the sheath resin is composed of a low melting point component and the core resin is composed of a high melting point component.

&Lt; 17 &

The three-dimensional sheet according to the above-mentioned <16>, wherein the sheath resin in the second heat-sealable fiber is made of a polyethylene resin.

<18>

The three-dimensional sheet according to the above-mentioned <16>, wherein the sheath resin of the second heat-sealable fiber is composed of a low melting point polyester or a low melting point polypropylene.

<19>

When the total amount of the first heat-sealable fiber and the second heat-sealable fiber is 100 parts by mass, the mixing ratio of the first heat-sealable fiber to the second heat-sealable fiber is preferably 10 parts by mass Or more and 70 parts by mass or less, based on the total weight of the three-dimensional sheet.

<20>

The average value of the number S1 of fiber fusion points per fiber density on the first face side of the first fiber layer and the number S2 of fiber fusion points per fiber density on the second face side of the first fiber layer is P1, The three-dimensional sheet according to any one of the above items <1> to <19>, wherein P1 is smaller than P2 when the number of fiber fusion points per fiber density is P2.

&Lt; 21 &

The three-dimensional sheet according to the above-mentioned &lt; 20 &gt;, wherein P1 is at least 55%, particularly preferably at least 65% of P2.

&Lt; 22 &

The three-dimensional sheet according to the above-mentioned &lt; 20 &gt; or &lt; 21 &gt;, wherein P1 is preferably 95% or less, particularly preferably 85% or less of P2.

&Lt; 23 &

The value of P1 is preferably not less than 150 /,, more preferably not less than 175 / 하고, more preferably not more than 240 /,, especially not more than 215 / ㎣, Sheet.

<24>

The value of P2 is preferably 220 / ㎣ or more, especially 240 / ㎣ or more, more preferably 300 / ㎣ or less, particularly preferably 280 / ㎣ or less, &Lt; / RTI &gt;

<25>

The three-dimensional sheet according to any one of the items <20> to <24>, wherein the fiber density serving as a basis of the calculation of P1 and P2 is the mass of the nonwoven fabric per unit volume, and ug / 로서 is used as a unit of fiber density.

&Lt; 26 &

The fiber density of the first side of the first fibrous layer means the fiber density in the layer positioned on the side of the first side when the first fibrous layer has a two-layer structure,

The fiber density on the second face side of the first fiber layer refers to the fiber density in the layer positioned on the second fiber layer side when the first fiber layer has a two-layer structure, Sheet.

&Lt; 27 &

The fiber density of the first side of the second fibrous layer refers to the fiber density at the first fibrous layer side when the thickness of the first fibrous layer is bisected when the second fibrous layer has a single layer structure, , And the three-dimensional sheet according to any one of the &lt; 20 &gt; to &lt; 26 &gt;, wherein the fiber density is in the layer positioned on the first fiber layer side.

&Lt; 28 &

The three-dimensional sheet according to any one of the above-mentioned <20> to <27>, wherein the number of fusion-bonding points is defined as the number of fusing points existing in the fiber when one fiber is inspected.

&Lt; 29 &

In the first fiber layer, any one of <20> to <28>, wherein the number S2 of fiber fusion points per fiber density on the second face side is smaller than the number S1 of fiber fusion points per fiber density on the first face side .

&Lt; 30 &

The three-dimensional sheet according to any one of the above-mentioned items, wherein S1 is preferably more than 100%, particularly preferably not less than 105% of S2.

&Lt; 31 &

The three-dimensional sheet according to any one of the items <20> to <200>, wherein S1 is preferably 300% or less, particularly preferably 125% or less of S2.

<32>

The absorbent article using the three-dimensional sheet according to any one of &lt; 1 &gt; to &lt; 31 &gt;.

&Lt; 33 &

The absorbent article as set forth in any one of <1> to <31>, wherein the first fibrous layer is opposed to the wearer's skin.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the scope of the present invention is not limited to these embodiments.

[Example 1]

The three-dimensional sheet 10 shown in Figs. 1 and 2 was manufactured by using the same apparatus as the apparatus shown in Figs. 2 to 6 of Japanese Laid-Open Patent Publication No. 2004-174234. The first fiber sheet 11a to be the raw material of the first fiber layer 11 in the three-dimensional sheet 10 is formed by using the fibers 1 and 2 on the first surface side and the fibers 1 and 2 on the second surface side, 3) and fibers (4) were used. The fiber (1) was a core-sheath fiber of polyethylene terephthalate (PET) and polyethylene terephthalate (PE) with a fineness of 2.3 dtex, a core diameter D2 of 10.30 탆 and a superficial diameter of 16.18 탆. The core diameter ratio (sheath / core) A1 was 1.57. Details of the fibers (2), (3) and (4) were as shown in Table 2 below. The first fibrous sheet 11a was an air-through nonwoven fabric (basis weight 18 g / m2) having a two-layer structure. An air-through nonwoven fabric (basis weight 18 g / m 2) having a fiber composition shown in the following Table 2 was used as a second fiber sheet 12 a to be a raw material for the second fiber layer 12 in the three-dimensional sheet 10. The fibers used in this embodiment are all short fibers (fiber length 51 mm). Thus, a desired three-dimensional sheet was obtained.

[Example 2]

In this embodiment, as shown in Table 2, the fiber composition on the side of the second surface 112 in the first fiber sheet 11a of the two-layer structure used in Example 1 is different from that in Example 1. Other than that, the same procedure as in Example 1 was carried out to obtain a desired three-dimensional sheet.

[Example 3]

In this embodiment, as shown in Table 2, two kinds of heat-sealable fibers are blended on the first face 111 side as the first fiber sheet 11a having a two-layer structure, Through nonwoven fabric in which one kind of heat-sealable fiber is blended with the thermosetting resin. Other than that, the same procedure as in Example 1 was carried out to obtain a desired three-dimensional sheet.

[Example 4]

In this example, as shown in Table 2, an air-through nonwoven fabric having a single-layer structure was used as the first fiber sheet 11a, and two types of heat-sealable fibers were blended as constituent fibers of the air- Yes. Other than that, the same procedure as in Example 1 was carried out to obtain a desired three-dimensional sheet.

[Examples 5 and 6]

In this embodiment, as shown in Table 2, the types of fibers on the second surface 112 side of the first fiber sheet 11a of the two-layer structure used in Example 1 are different from those of Example 1 will be. Other than that, the same procedure as in Example 1 was carried out to obtain a desired three-dimensional sheet.

[Examples 7 and 8]

In this embodiment, as shown in Table 2, the use ratio of the fibers on the second surface 112 side of the first fiber sheet 11a of the two-layer structure used in Example 6 is different from that of Example 6 It is. Other than that, the same procedure as in Example 6 was carried out to obtain a desired three-dimensional sheet.

[Examples 9 and 10]

In this embodiment, as shown in Table 2, the core sheath component of the fiber 4, which is the fiber on the second surface 112 side in the first fiber sheet 11a of the two-layer structure used in Example 6, And the ratio is different from that in Example 6. Other than that, the same procedure as in Example 6 was carried out to obtain a desired three-dimensional sheet.

[Example 11]

In this example, as shown in Table 2, an air-through nonwoven fabric having a single-layer structure was used as the first fiber sheet 11a, and two types of heat-sealable fibers were blended as constituent fibers of the air- Yes. Other than that, the same procedure as in Example 1 was carried out to obtain a desired three-dimensional sheet.

[Comparative Example 1]

In this comparative example, as shown in Table 3, only the first fiber sheet 11a is used, and the second fiber sheet 12a is not used in the first embodiment, Through nonwoven fabric. This air through nonwoven fabric corresponds to the nonwoven fabric disclosed in Patent Document 3. [

[Comparative Example 2]

In this Comparative Example, as shown in Table 3, an air-through nonwoven fabric having a single-layer structure was used as the first fiber sheet 11a, and one type of heat-sealable fiber was blended as the constituent fiber of the air- Yes. Other than that, the same as Example 1 was made. The sheet obtained in this Comparative Example corresponds to the sheet described in Patent Document 1. [

[Comparative Example 3]

As shown in Table 3, this example is an example of using only one type of fiber as the fiber on the second surface 112 side of the first fiber sheet 11a of the two-layer structure used in Example 1 . Other than that, the same as Example 1 was made. The sheet obtained in this Comparative Example corresponds to the sheet described in Patent Document 2, and the convex portion has a solid structure.

〔evaluation〕

With respect to the sheets obtained in Examples and Comparative Examples, the thickness of each fiber layer, fiber density, and fusion score were measured by the above-described method. Further, the value of fusion score / fiber density was calculated. For measurement of the fusion point, a scanning electron microscope image as shown in Fig. 9 (Example 7) and Fig. 10 (Comparative Example 2) was taken. In these drawings, the area surrounded by a circle is a fusion point. In addition, the following methods were used to measure and evaluate fluff-dropping resistance, smoothness of the first fibrous layer surface, cushioning feeling of the sheet, low stimulus to the skin of the sheet, and texture. The results are shown in Tables 4 and 5.

[Pilling Elimination]

Test pieces of 200 mm in the X direction (width direction) and 200 mm in the Y direction (longitudinal direction) were taken out from the nonwoven fabric obtained in Examples 1 to 11 and Comparative Examples 1 to 3, . Specifically, the test piece was fixed on the plate with a check tape with the evaluation surface facing upward. A friction plate with a sponge (Mortopren MF-30) wrapped around it was set on the specimen. The load of the sponge was 240 g. Three sets of forward rotation and three sets of reverse rotation were set as one set, and the friction plate was rotated. This was done in 15 sets. One rotation was made at a speed of 3 seconds. Thereafter, all the fibers attached to the sponge by the rotation were attached to the transparent adhesive tape. This adhesive tape was attached to the black ground. From the surface state of the test piece and the fibers attached to the adhesive tape, the degree of the fluff drop was visually evaluated according to the following criteria.

One point was scored from 5 points out of 0.25 points each time there was a fluff drop, and one point was scored when there were 16 points or more. The results for each score are generally as follows.

5 points: The test specimen has very few lint or curl nodes. There is little adhesion of the fibers to the adhesive tape.

4 points: Fuzz is found on the specimen, but there are few curl nodes. There is almost no adhesion of the fibers to the adhesive tape.

3 point: Lint or curl node is found on the specimen, but there is no lump of fiber on the adhesive tape.

1 point: Lint or curl node is observed on the test piece, and it is confirmed that the adhesive tape is a lump of fiber.

〔lubricity〕

The friction coefficient MMD of the first surface of the first fibrous layer was measured using KES-FB4-AUTO-A, an automated surface testing machine manufactured by KATO TEC CO., LTD.

[Cushion feeling]

Compressed energy WC per 1 cm &lt; 2 &gt; was measured using KES-FB3-AUTO-A, an automated compression tester manufactured by KATTEC CO., LTD.

[Low irritation to the skin of the sheet]

The three-dimensional sheet 10 was attached to the terminal, and the arms were rotated at a load of 3.0 kPa in a range of 40 mm in a range of 40 mm over one second, and the feel of the arm was evaluated in three steps did.

A: I do not have any pain, or I feel good.

B: I'm not kidding.

C: It hurts and hurts.

[Texture]

In the blindness state, Comparative Example 2 was scored as five points of texture and scores of ten were scored, and the average was regarded as a score of texture.

As is evident from the results shown in Tables 2 to 5, the three-dimensional sheet obtained in each of the Examples is lower in friction coefficient on the uneven surface and smoother than the sheet obtained in Comparative Example 2. It can also be seen that the three-dimensional sheet obtained in each of the Examples has a lower stimulus to the skin, a higher cushioning feeling, and a better texture than the sheet obtained in each Comparative Example.

Industrial availability

As described in detail above, the three-dimensional sheet of the present invention has a cushion feeling caused by the convex portion, and the smoothness of the convex portion is improved. Further, in the three-dimensional sheet of the present invention, the uprightness of the convex portion and the difficulty of crushing the convex portion when the load is applied are improved.

Claims (73)

A first fiber layer having a first side and a second side opposite to the first side, and a second fiber layer having a first side and a second side opposite to the first side,
The second surface of the first fibrous layer and the first surface of the second fibrous layer are opposed to each other,
The first fiber layer and the second fiber layer are formed so as to protrude in the direction away from the second fibrous layer to form a plurality of convex portions,
The first fibrous layer and the second fibrous layer are both made of nonwoven fabric,
Wherein the first fiber layer comprises at least two kinds of fibers comprising a first fiber and a second fiber,
The first fiber and the second fiber each contain a high melting point component and a low melting point component,
Wherein a diameter ratio of the high melting point component and the low melting point component of the first fiber and a diameter ratio of the high melting point component and the low melting point component of the second fiber are different from each other, ₂ is 1.1 or more and 1.2 or less.
Diameter ratio of the high melting point component and the low melting point component A _X = the diameter of the low melting point component of the Xth fiber D1 / the diameter of the high melting point component of the Xth fiber D2 The method according to claim 1,
Wherein the first fiber layer has a multilayer structure including an upper layer on the first surface side and a lower layer on the second surface side and one or both of the upper layer on the first surface side and the lower layer on the second surface side include plural kinds of fibers A three-dimensional sheet. A first fiber layer having a first side and a second side opposite to the first side, and a second fiber layer having a first side and a second side opposite to the first side,
The second surface of the first fibrous layer and the first surface of the second fibrous layer are opposed to each other,
The first fiber layer and the second fiber layer are formed so as to protrude in the direction away from the second fibrous layer to form a plurality of convex portions,
The first fibrous layer and the second fibrous layer are both made of nonwoven fabric,
Wherein the first fiber layer comprises at least two kinds of fibers comprising a first fiber and a second fiber,
Wherein the first fiber layer has a multilayer structure including an upper layer on the first surface side and a lower layer on the second surface side, wherein one of the layers includes a plurality of kinds of fibers,
The first fiber and the second fiber each contain a high melting point component and a low melting point component,
Wherein the diameter ratio of the high melting point component and the low melting point component of the first fiber and the diameter ratio of the high melting point component and the low melting point component of the second fiber are different from each other.
Diameter ratio of the high melting point component and the low melting point component A _X = the diameter of the low melting point component of the Xth fiber D1 / the diameter of the high melting point component of the Xth fiber D2 A first fiber layer having a first side and a second side opposite to the first side, and a second fiber layer having a first side and a second side opposite to the first side,
The second surface of the first fibrous layer and the first surface of the second fibrous layer are opposed to each other,
The first fiber layer and the second fiber layer are formed so as to protrude in the direction away from the second fibrous layer to form a plurality of convex portions,
The first fibrous layer and the second fibrous layer are both made of nonwoven fabric,
Wherein the first fiber layer comprises at least two kinds of fibers comprising a first fiber and a second fiber,
Wherein the first fiber layer has a multilayer structure including an upper layer on the first face side and a lower layer on the second face side, wherein one of the layers includes a plurality of kinds of fibers, the other layer includes only one kind of fibers,
The first fiber and the second fiber each contain a high melting point component and a low melting point component,
Wherein the diameter ratio of the high melting point component and the low melting point component of the first fiber and the diameter ratio of the high melting point component and the low melting point component of the second fiber are different from each other.
Diameter ratio of the high melting point component and the low melting point component A _X = the diameter of the low melting point component of the Xth fiber D1 / the diameter of the high melting point component of the Xth fiber D2 5. The method according to any one of claims 1 to 4,
Wherein the first fiber has a larger diameter ratio than the second fiber,
And said second fibers are at least contained in a lower layer of said second surface side. A first fiber layer having a first side and a second side opposite to the first side, and a second fiber layer having a first side and a second side opposite to the first side,
The second surface of the first fibrous layer and the first surface of the second fibrous layer are opposed to each other,
The first fiber layer and the second fiber layer are formed so as to protrude in the direction away from the second fibrous layer to form a plurality of convex portions,
The first fibrous layer and the second fibrous layer are both made of nonwoven fabric,
Wherein the first fiber layer comprises at least two kinds of fibers comprising a first fiber and a second fiber,
The first fiber layer has a multilayer structure including an upper layer on the first surface side and a lower layer on the second surface side,
The first fiber and the second fiber are contained in the lower layer on the second surface side,
The first fiber and the second fiber each contain a high melting point component and a low melting point component,
Wherein a value of a direct diameter ratio A ₁ of the high melting point component and the low melting point component of the first fiber is 1.3 or more and 2.0 or less and a ratio of a direct ratio of the high melting point component and the low melting point component of the second fiber, A _two- dimensional sheet having a value of 1.1 or more and 1.8 or less, provided that the value of A ₂ is smaller than A ₁ .
Diameter ratio of the high melting point component and the low melting point component A _X = the diameter of the low melting point component of the Xth fiber D1 / the diameter of the high melting point component of the Xth fiber D2 The method according to any one of claims 1 to 4 and 6,
Wherein the first fiber layer and the second fiber layer contain the same kinds of heat-sealable fibers. The method according to any one of claims 2 to 4 and 6,
Wherein the first fiber has a larger diameter ratio than the second fiber,
And the second fiber layer comprises the first fiber. The method according to any one of claims 2 to 4 and 6,
Wherein the heat-sealable fiber of the same type is contained in the upper layer on the first surface side and the lower layer on the second surface side. The method according to any one of claims 2 to 4 and 6,
Wherein the first fiber has a larger diameter ratio than the second fiber,
And the upper layer on the first surface side is composed of only the first fiber. The method according to any one of claims 2 to 4 and 6,
Wherein the first fiber has a larger diameter ratio than the second fiber,
And the second fibers are disposed only on a lower layer of the second surface side. An absorbent article using the three-dimensional sheet according to any one of claims 1 to 4. The absorbent article as set forth in any one of claims 1 to 4, wherein the three-dimensional sheet is used so that the first fiber layer faces the skin of the wearer. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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