JP2007130178A - Three-dimensional sheet for absorptive article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a three-dimensional sheet for an absorptive article, which is excellent in the stability of the three-dimensional shape of a projected part and the guiding property of liquid to an open hole. <P>SOLUTION: The three-dimensional sheet 1 for the absorptive article is composed of nonwoven fabric 10 having many ridge parts (projected parts) 2 and having the open holes 31 formed between the ridge parts (projected parts) 2 adjacent to each other, and at least a part 21 of the ridge parts (projected parts) 2 is made into a film. For the ridge parts 2 in a desirable three-dimensional sheet 1, the side face of the ridge part 2 is made into a film and the peak part of the ridge part 2 is not made into a film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a three-dimensional sheet used as a constituent material of absorbent articles such as sanitary napkins, panty liners (corimono sheets), incontinence pads, disposable diapers and the like.

DESCRIPTION OF RELATED ART Conventionally, the surface sheet of the absorbent article which consists of a nonwoven fabric which has many convex parts and in which the opening was formed between the convex parts adjacent to each other is known widely.
In such a non-woven fabric, it is expected that the liquid excreted is quickly separated from the surface of the wearer's skin by a large number of convex portions, and further, the liquid is quickly transferred to the absorber through the openings.
However, in the conventional topsheet, the expected performance may not be obtained due to collapse or collapse of the convex portion.
First, the applicant of the present invention comprises a nonwoven fabric having a three-dimensional aperture provided with a liquid guide tube surrounded and surrounded by a nonwoven fabric, and melts and solidifies the heat-sealing fibers contained as constituent fibers of the nonwoven fabric. The surface sheet of the absorbent article which formed the film-forming area | region in the at least inner surface of the pipe | tube was proposed (refer patent document 1). According to this surface sheet, the three-dimensional shape of the holes is stably maintained.
However, this surface sheet is not always sufficient in terms of the stability of the three-dimensional shape of the convex portion.

JP 2004-275296 A

  Therefore, the objective of this invention is providing the solid sheet for absorbent articles excellent in the stability of the solid shape of a convex part. For example, when a three-dimensional sheet is used as a top sheet of an absorbent article, effects such as excellent liquid cushioning and a liquid residue hardly occur on the surface.

The present invention relates to a three-dimensional sheet for absorbent articles, which is made of a nonwoven fabric having a large number of convex portions and having openings formed between adjacent convex portions, and at least a part of the convex portions is formed into a film. The object is achieved by providing.

  The three-dimensional sheet of the present invention is excellent in the stability of the three-dimensional shape of the convex portion.

The present invention will be described below based on preferred embodiments with reference to the drawings.
FIG. 1 shows a perspective view of a three-dimensional sheet (hereinafter also simply referred to as a three-dimensional sheet) for absorbent articles according to an embodiment of the present invention, and FIG. 2 shows the three-dimensional sheet shown in FIG. FIG. 3 is an enlarged cross-sectional view of a plane orthogonal to the longitudinal direction of the collar portion of the three-dimensional sheet shown in FIG.

As shown in FIGS. 1 to 3, the three-dimensional sheet 1 of the present embodiment has a large number of collars (convex parts) 2, and an opening 31 is formed between adjacent collars 2 and 2. It consists of a nonwoven fabric 10.
Each of the plurality of flanges 2 extends in one direction of the three-dimensional sheet 1 and is formed in parallel to each other. The flanges 2 are formed at regular intervals in a direction (hereinafter also referred to as X direction) orthogonal to the longitudinal direction of the flange 2 in the three-dimensional sheet 1. Moreover, the opening 31 is formed in the base 3 existing between the adjacent flanges 2 and 2, and in the three-dimensional sheet 1, a direction parallel to the longitudinal direction of the flange 2 (hereinafter also referred to as Y direction). Are formed at regular intervals.

  As a nonwoven fabric which comprises the three-dimensional sheet 1, a conventionally well-known nonwoven fabric can be especially used without a restriction | limiting. For example, various nonwoven fabrics such as an air-through nonwoven fabric, a spunbond nonwoven fabric, a meltblown nonwoven fabric, a spunlace nonwoven fabric, and a needle punched nonwoven fabric obtained by hot-air treatment of a heat-bonded fiber web produced by the card method are used as concrete three-dimensional sheets. It can be appropriately selected depending on the purpose and application. There is no restriction | limiting in particular in the coupling | bonding means of the fiber in these nonwoven fabrics, For example, the coupling | bonding by a binder and the coupling | bonding by heat sealing | fusion can be used. Further, instead of fiber bonding, mechanical entanglement of fibers such as spunlace nonwoven fabric may be used. In order to realize a smooth texture and softness on a three-dimensional sheet, an air-through that has been made into a non-woven fabric by applying hot air treatment to the heat-bonded fiber web obtained by the card method as a non-woven fabric, without giving strong compression Nonwoven fabric is most preferably used.

  As shown in FIG. 3, the opening 31 is a three-dimensional opening provided with a liquid introduction pipe 32 surrounded by a nonwoven fabric extending from the front surface 1 </ b> A side to the back surface 1 </ b> B side of the three-dimensional sheet 1. Yes. The surface 1A side of the three-dimensional sheet 1 is the surface side having the ridge part (convex part) 2, and when the three-dimensional sheet 1 is used as the surface sheet of the absorbent article, the surface side directed toward the wearer's skin side. is there. The back surface 1B side of the three-dimensional sheet 1 is the opposite surface.

  The inner surface 32 </ b> A of the liquid guide tube 32 is formed by a continuous surface from the upper surface 3 </ b> A of the base portion 3 of the three-dimensional sheet 1. In the three-dimensional opening 31, the peripheral edge 32 </ b> B is located at the lower end of the opening 31 as shown in FIG. 3. Examples of the liquid guide tube 32 include a cylindrical shape and a cone-shaped shape in which the diameter of the liquid guide tube 32 gradually increases from the front surface 1A side to the back surface 1B side. As shown in FIG. 3, an inverted conical shape in which the diameter of the liquid guide tube 32 gradually decreases from the front surface 1A side to the back surface 1B side is preferable. The shape of the cross section of the opening 31 is not particularly limited, and may be, for example, an elliptical, triangular, or quadrangular opening. However, as shown in FIG. This is preferable because the soft feeling of the sheet 1 can be improved.

  The opening 31 has an opening diameter of 0.5 to 3 mm, particularly 0.7 to 1.5 mm, at the lower end 32B, so that the stability of the liquid introduction tube 32, the liquid permeability and the liquid concealing property can be improved. It is preferable from the point of improvement. From the viewpoint of improving the permeability of the liquid, the porosity of the three-dimensional sheet 1 is preferably 3 to 30%, more preferably 5 to 25%, and still more preferably 10 to 20%. The hole area ratio is a value obtained by dividing the area of the opening 31 formed when the three-dimensional sheet 1 is projected from the front surface 1A side to the back surface 1B side by the area of the three-dimensional sheet 1. Specifically, the hole diameter and the hole area ratio are measured by the following methods.

[Measurement method of hole diameter and hole area ratio]
Light source [Sunlight SL-230K2; manufactured by LPL Co., Ltd.], stand [Copy stand CS-5; manufactured by LPL Co., Ltd.], lens [24 mm / F2.8D Nikkor lens], CCD camera [(HV-37 Connection with lens by F mount) and a video board, the image on the back surface 1B side of the three-dimensional sheet 1 is captured. The captured image is binarized by image analysis software (ver. 4.21) manufactured by NEXUS. A circle-equivalent diameter is obtained from the binarized image and is used as the opening diameter. The area of the binarized portion is divided by the area of the entire image to obtain the hole area ratio (%). If it is difficult to measure the aperture diameter, an auxiliary process such as painting the aperture on the screen is performed.

As shown in FIG. 3, the cross-sectional shape in the width direction of the collar portion 2 is curved in a convex shape toward the front surface 1A side, as shown in FIG. It is preferable that the pitch (for example, the space | interval between vertices) of the X direction of the adjacent collar parts 2 and 2 is 1.0-6.0 mm, especially 2.0-4.0 mm. Similarly, the pitch between the adjacent openings 31 in the X direction (for example, the distance between the center points) is preferably 1.0 to 6.0 mm, and particularly preferably 2.0 to 4.0 mm. The longitudinal direction of the collar portion 2 may or may not coincide with the machine direction at the time of manufacturing the nonwoven fabric that is the raw fabric of the three-dimensional sheet 1.
The pitch of the apertures 31 in the Y direction (for example, the interval between the center points of the apertures) is preferably 0.4 to 40 mm, particularly 1.5 to 8 mm.

In the three-dimensional sheet 1 of this embodiment, the side surfaces 21 and 21 of the collar part 2 are formed into a film.
Filming is a state in which at least the resin having the lowest melting point among the constituent resins of the constituent fibers of the nonwoven fabric is softened (preferably melted and solidified) so that the constituent fibers are in close contact with each other in the form of a film. It is preferable that the fiber shape is almost lost. The film-formed portion 21 a on the side surface 21 of the flange portion 2 is thinner than the other portions of the flange portion 2 and has a higher density. Further, the surface is smoother than other portions.

  The collar portion 2 of the three-dimensional sheet 1 is less likely to be crushed or fallen because the side surfaces 21 and 21 are formed into a film. Thereby, when it uses as a surface sheet of an absorbent article, the collar part 2 falls down and the opening 31 is blocked, or the collar part 2 is crushed and the liquid easily flows over the collar part 2 in the X direction. Inconveniences such as becoming can be prevented.

In addition, the filmed portion (hereinafter also referred to as a filmed portion) has increased water repellency, the excreted liquid is not retained, and the liquid is repelled, so that it is formed close to the heel part 2. The liquid moves smoothly into the opening 31.
The film-formed portion 21a is 10% or more of the height T of the flange portion 2 in particular from the viewpoint of improving the shape stability of the flange portion (convex portion) 2 and / or guiding the liquid to a smooth opening, in particular 50 % Over a height t of at least%. The height T of the heel is preferably 0.5 to 3.0 mm or more, and more preferably 0.5 to 2.0 mm.

  Moreover, in the three-dimensional sheet 1 of this embodiment, the top part 22 of the collar part 2 is not formed into a film. Since the top part 22 of the collar part 2 is not formed into a film, the texture is good. The top portion 22 of the heel part 2 is where the three-dimensional sheet 1 is used as a surface sheet of an absorbent article, for example, where it directly touches the wearer's skin. The touch and cushioning properties during use can be improved.

  When the cross-sectional shape of the three-dimensional sheet 1 in the direction (X direction) perpendicular to the flange portion 2 is compared between a portion having the opening 31 and a portion not having the opening 31, there is a difference in shape depending on the presence or absence of the opening 31. is there. That is, when the cross-sectional shape shown in FIG. 3A is compared with the cross-sectional shape shown in FIG. 3B, the cross-sectional shape of the portion D below the plane indicated by the straight line L in FIG. Yes. Thus, the portion D having a difference in shape due to the presence / absence of the opening 31 is not included in a part of the flange 2 and is a portion having no difference in shape due to the presence / absence of the opening 31 (indicated by a straight line L in FIG. Only the part U) above the plane is considered as the buttocks.

From the viewpoint of forming a film-forming portion having excellent water repellency, the synthetic fiber of the nonwoven fabric is a synthetic fiber such as a polyester such as polyethylene (PE), polypropylene (PP) or polyethylene terephthalate (PET), or a polyamide such as nylon. Are preferably used, and are composite fibers such as a core-sheath fiber, a side-by-side fiber, and a split fiber having a resin having a high melting point as a core and a resin having a low melting point as a sheath from the viewpoint of heat sealability (film formation). It is preferable.
The basis weight of the nonwoven fabric is 15 to 50 g / m ² , particularly 20 to 30 g / m ² , and it is easy to form a filmed portion, the texture, texture and openness of the solid sheet 1 as a whole. To preferred.
In addition, the liquid introduction pipe | tube 32 part of the opening 31 in the solid sheet 1 of this embodiment is not made into a film.

As shown in FIG. 4, the three-dimensional sheet 1 of the present embodiment is easy and easy by interposing and pressing the nonwoven fabric 10 ′ as a raw fabric between the first pressing mold 51 and the second pressing mold 53. It can be manufactured efficiently.
The first pressing die 51 has a number of pyramid or cone-shaped perforated pins (convex pins) 52 in a row along the conveying direction of the nonwoven fabric 10 ′, and the rows are arranged in multiple rows. It consists of pin rolls. The second pressing die 53 is constituted by a ridge roll having a ridge portion 54 fitted between the multi-row convex pins in the first pressing die 51.
Further, as shown in FIG. 5, the pin roll and the ridge roll have a clearance between the side surface of the base portion 55 of the perforated pin 52 and the side surface of the ridge portion 54 of the ridge roll, and the nonwoven fabric 10 ′. The side surface of the pedestal portion 55 and / or the side surface of the ridge portion 54 is made of a resin having the lowest melting point among the resins constituting the constituent fibers of the nonwoven fabric 10 ′. It should be above the softening point or melting point.

  As a result of pressing between the first pressing mold 51 and the second pressing mold 53, the nonwoven fabric 10 ′ is deformed so as to form the collar part 2 by the protruding part 54, and is formed into a film on the side surface of the collar part 2. A portion 21a is formed. At the same time, the opening 31 is formed by pressing the punch pin 52 against the nonwoven fabric.

  Hereinafter, other embodiments of the three-dimensional sheet for absorbent articles of the present invention will be described. About these embodiment, a different point from the solid sheet 1 mentioned above is demonstrated, and description is abbreviate | omitted about the same point. About the point which is not demonstrated especially, the description about the three-dimensional sheet 1 mentioned above is applied suitably. In addition, the same code | symbol is attached | subjected to the same member.

The three-dimensional sheet 1 </ b> A shown in FIG. 6 intermittently has film-formed portions 21 a in the longitudinal direction of the flange portion 2. Moreover, the film formation part 21a is formed at equal intervals with the same pitch as the pitch of the Y direction of the opening 31, and each opening 31 is located just beside the film formation part 21a of the collar part 2. FIG. . The length of the film-formed portion 21a in the Y direction is preferably 1.0 times or more, particularly 1.5 to 2.0 times the diameter of the opening diameter of the opening 31, for example.
By providing the film-formed portion 21a intermittently in the longitudinal direction of the collar portion 2, not only the liquid does not remain in the film-formed portion but also the liquid is caused by the capillary force due to the density gradient in the film-formed peripheral portion and the non-film-formed portion. Since it becomes easy to move, in addition to the effect of improving the stability of the three-dimensional shape of the heel part 2, it is possible to improve the touch and the smooth feeling. Moreover, in addition to said effect, the inductivity of the liquid to the opening 31 is excellent by positioning the opening 31 just beside the film-formed part 21a.
Note that the cross-sectional view taken along the line III-III in FIG. 6A is the same as FIG.

As for the solid sheet 1B shown in FIG. 7, the whole collar part 2 is made into a film. That is, in the width direction of the collar part 2, as shown in FIG.7 (b), as for the collar part 2, the whole region ranging from the one side surface 21 through the top part 22 to the other side surface 21 is formed into a film, Such a cross-sectional structure is continuous in the longitudinal direction of the flange 2.
Since the entire heel part 2 is formed into a film, the shape stability of the heel part 2 and the inductivity of the liquid into the opening 31 are excellent, and the excreted liquid does not remain on the surface of the heel part 2 at all. Therefore, it is excellent in a light feeling.

  As shown in FIG. 8, the three-dimensional sheet 1 </ b> B illustrated in FIG. A pressing surface 56 having a cross-sectional shape that substantially matches the shape of the strip 54 is formed, and the entire nonwoven fabric portion that is pressed between the adjacent pedestal portions 55 and 55 in the nonwoven fabric pressed between the pedestal portions 55 is heated and compressed. Except for the above, the three-dimensional sheet 1 described above can be manufactured by a preferable manufacturing method.

The film-formed portion 21a in the three-dimensional sheet 1C shown in FIG. 9 is the same as the above-described three-dimensional sheet 1B in that it extends from one side surface 21 to the other side surface 21 of the collar part 2, but in the three-dimensional sheet 1C. The film-formed portion 21 a is intermittently formed in the longitudinal direction of the flange portion 2.
The three-dimensional sheet 1 </ b> C in FIG. 9 is excellent in shape stability of the flange portion 2, and since the film-formed portion is formed directly beside the opening 31, the liquid inductivity to the opening 31 is excellent. Furthermore, since it is intermittent in the longitudinal direction of the collar part 2, a touch and a smooth feeling can be improved.
The three-dimensional sheet 1C shown in FIG. 9 has a pressurization surface 56 of the pin roll used in FIG. 8 or a ridge portion 54 of the ridge roll with a pressurization convex portion and a concave portion for forming a non-pressurized portion in the circumferential direction. It can be manufactured in the same manner as the three-dimensional sheet 1B of FIG.

As mentioned above, although demonstrated based on preferable embodiment of the solid sheet of this invention, the solid sheet of this invention is not restrict | limited to said each embodiment, A various change is possible in the range which does not deviate from the meaning of this invention.
For example, the apertures 31 of the adjacent base portions 3 do not have to be arranged in a horizontal row, and may be shifted by a half pitch in adjacent rows, for example. In addition, when the film-formed portion is intermittently formed in the longitudinal direction of the collar portion, the film-formed portion may be formed just beside the opening 31 and the opening 31. Moreover, you may vary the pitch of an opening or a film-forming part for every collar part.
The number of the collar portions 2 having the film-formed portion 21a formed on a single three-dimensional perforated sheet is not particularly limited, but is preferably about 3.5 to 6 / cm.
The description omitted in one embodiment described above and the requirements of only one embodiment can be applied to other embodiments as appropriate, and the requirements in each embodiment can be appropriately changed between the embodiments. Can be substituted.

The three-dimensional sheet of the present invention is preferably used as a surface sheet of an absorbent article. Examples of the absorbent article include sanitary napkins, panty liners (orimono sheets), incontinence pads, disposable diapers, hygiene pads, nursing pads, and the like. Is mentioned.
When used as a surface sheet, the convex portions and the openings may be partially used not only on the entire surface sheet but only on the side portion or the central portion of the absorbent article.
Moreover, it can also be used as other than a surface sheet, for example, it can also be used for the second sheet etc. which are located under the surface sheet and above the absorber. In these cases, the side having the flange portion 2 is used as the surface sheet side. Moreover, it can be located between an absorber and a back surface sheet, or can be used as an intermediate layer of the absorber.
Further, the nonwoven fabric is not limited to a single layer, and may have a multilayer structure. Moreover, a convex part is not restricted to the collar part continuous in one direction, You may arrange | position many independent convex parts discretely.

It is a perspective view showing one embodiment of a solid sheet for an absorptive article of the present invention. It is the top view which looked at the solid sheet shown in FIG. 1 from the surface side which has a collar part (convex part). It is an expanded sectional view in the direction orthogonal to a collar part of the solid sheet shown in FIG. 1, (a) is II sectional view taken on the line, (b) is II-II sectional view. It is explanatory drawing of the preferable manufacturing method of the solid sheet shown in FIG. It is a figure which expands and shows a part of FIG. It is (a) top view [figure 2 equivalent figure] and (b) IV-IV sectional view taken on the line of (a) which shows other embodiment of the solid sheet of this invention. (A) Top view (figure 2 equivalent figure) and (b) The VV sectional view taken on the line of (a) which shows other embodiment of the solid sheet of this invention. FIG. 8 is an explanatory diagram of a preferred method for producing the three-dimensional sheet shown in FIG. It is a top view (figure 2 equivalent figure) showing other embodiments of a solid sheet of the present invention.

Explanation of symbols

1, 1A-1C Three-dimensional sheet for absorbent article 2 Gutter part 21 Gutter part side surface 21a Filmed part 3 Base part 31 Open hole 32 Liquid conduit

Claims (7)

  A three-dimensional sheet for absorbent articles, which is made of a non-woven fabric having a large number of protrusions, with openings formed between adjacent protrusions, and at least a part of the protrusions being formed into a film.   The absorbent article according to claim 1, wherein a plurality of flanges are formed, the opening is formed between adjacent flanges, and at least a part of the flanges is formed into a film. Three-dimensional sheet.   The three-dimensional sheet for absorbent articles according to claim 2, wherein a side surface of the flange portion is formed into a film, and a top portion of the flange portion is not formed into a film.   3. The three-dimensional sheet for absorbent articles according to claim 2, wherein the collar portion is formed into a film in the entire width direction from one side surface to the other side surface in the longitudinal direction.   The three-dimensional sheet | seat for absorbent articles of Claim 3 or 4 which has the part filmed in the longitudinal direction of the said collar part intermittently.   The three-dimensional sheet | seat for absorbent articles of Claim 4 in which the said opening is located just beside the film-formed part of the said collar part. The three-dimensional sheet | seat for absorbent articles of Claim 4 by which the whole said collar part is formed into a film.

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