JP2006255051A - Surface sheet of absorbent article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface sheet of an absorbent article where a body liquid such as catamenia supplied to the surface is shifted speedily to an absorbing body without being noticeable. <P>SOLUTION: The surface sheet 1 of an absorbent article having a large number of openings has a two-layer structure of an upper fiber layer 7 positioned on a front surface side and a lower fiber layer 7' positioned on a rear surface side. The openings 6 are formed surrounded by the two layers 7 and 7' respectively extended from the front surface side to the rear surface side of the surface sheet 1. Between the two layers 7 and 7', top parts 5 having spaces are provided. The two layers 7 and 7' at the peripheries of the openings 6 are in contact with each other, and different hydrophilic treatments are used to the two layers 7 and 7', so that surface tension of the liquid due to contact of the liquid changes more easily on the lower fiber layer 7' than the higher fiber layer 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a surface sheet of an absorbent article such as a sanitary napkin, a panty liner (corimono sheet), an incontinence pad, and a disposable diaper.

Since there is a film-type product, delete it.
Conventionally, as a surface sheet of absorbent articles such as sanitary napkins and disposable diapers, perforated films or non-woven fabrics are often used.
The applicant of the present invention is a surface sheet of an absorbent article made of a nonwoven fabric having a large number of apertures as a surface sheet with improved dryness, softness and softness, and has at least two layers of nonwoven fabric And proposed a surface sheet in which the nonwoven fabrics are joined to each other at the peripheral edge of the aperture (see Patent Document 1).
Further, there has been proposed an absorbent article in which a surface sheet of an absorbent article and an intermediate sheet disposed thereunder are bonded, and a durable hydrophilic oil agent is adhered to the fibers constituting the intermediate sheet (see Patent Document 2). ).

Japanese Patent Laid-Open No. 10-80445 JP 2003-175074 A

  However, the surface sheet described in Patent Document 1 leaves room for improvement in that the body fluid supplied to the surface is inconspicuous and the body fluid is quickly moved to the absorber. In the laminated structure of the surface sheet and the intermediate sheet described in Patent Document 2, a durable hydrophilic oil agent is used for the fibers constituting the intermediate sheet, but as the body fluid supplied increases, the liquid remaining in the surface sheet increases. It becomes difficult to move to the intermediate layer and guide to the absorber, and the body fluid supplied to the surface cannot be made inconspicuous.

  Therefore, the objective of this invention is providing the surface sheet of the absorbent article which can be rapidly transferred to an absorber, without making body fluids, such as menstrual blood supplied to the surface, stand out.

  The present invention is a top sheet of an absorbent article comprising a fiber assembly having a large number of apertures, wherein the top sheet has a two-layer structure of a top fiber layer on the front side and a bottom fiber layer on the back side. The opening is surrounded and formed by the two layers extending from the front side to the back side of the topsheet, and has a top portion having a space between the two layers. The two layers at the periphery of the opening are in contact with each other, and different hydrophilic treatment agents are used for the two layers, and the lower fiber layer is more liquid than the upper fiber layer. The object is achieved by providing a surface sheet of an absorbent article in which a change in the surface tension of the liquid easily occurs due to contact.

  According to the top sheet of the absorbent article of the present invention, the body fluid such as menstrual blood supplied to the surface can be quickly transferred to the absorbent body without conspicuous.

  Hereinafter, the present invention will be described based on a preferred embodiment thereof with reference to the drawings. Here, FIG. 1 is an enlarged plan view showing a main part of one embodiment of the surface sheet of the absorbent article of the present invention, and FIG. 2 is a partial cross-sectional view along the line AA in FIG. FIG. 3 is a perspective view of the top sheet shown in FIG.

As shown in FIGS. 1 to 3, the surface sheet 1 of this embodiment has a large number of apertures 6, 6,... And has a two-layer structure of an upper fiber layer 7 and a lower fiber layer 7 ′. is doing.
The upper fiber layer 7 is located on the surface side of the top sheet 1 (the side facing the wearer's skin when using the top sheet), and the lower fiber layer 7 ′ is on the back side of the top sheet 1 (use of the top sheet) It is sometimes located on the side facing away from the wearer's skin. The two fiber layers 7 and 7 ′ in the surface sheet 1 of the present embodiment are both made of nonwoven fabric. Hereinafter, the nonwoven fabric constituting the upper fiber layer 7 is also referred to as the nonwoven fabric 7 or the upper nonwoven fabric 7, and the nonwoven fabric constituting the lower fiber layer is also referred to as the nonwoven fabric 7 ′ or the lower nonwoven fabric 7 ′.

  As shown in FIGS. 2 and 3, the opening 6 is formed so as to be surrounded by two layers of nonwoven fabrics 7 and 7 ′ extending from the front surface side 1 </ b> A to the back surface side 1 </ b> B of the topsheet 1. The inner wall 10 of the opening 6 is formed by a continuous surface from the surface 8 </ b> A of the topsheet 1. That is, the opening 6 is a three-dimensional opening. As an aspect of the three-dimensional opening, for example, an opening in which the nonwoven fabric surrounding the opening 6 is cylindrical, or the diameter of the opening 6 gradually increases from the front surface side 1A toward the back surface side 1B. As shown in FIGS. 2 and 3, the diameter of the opening 6 gradually decreases from the front surface side 1A toward the back surface side 1B as shown in FIGS. The opening of is preferable. The shape of the opening 6 is not particularly limited, and may be, for example, an elliptical, triangular, or quadrangular opening. However, as shown in FIG. This is preferable from the viewpoint of improving the soft feeling. The opening 6 can be formed, for example, according to a preferable method for producing a surface sheet of the present invention described later.

  In the surface sheet 1 of this embodiment, as shown in FIG. 2, it is preferable that the diameter d of the lower end peripheral part of the opening 6 is 0.5-2.0 mm. Moreover, it is preferable that the porosity of the surface sheet 1 of this embodiment is 5% or more, It is further more preferable that it is 7% or more, It is much more preferable that it is 10 to 20%. The aperture ratio is a value obtained by dividing the area of the aperture formed when the topsheet 1 of the present embodiment is projected from the top surface 1A to the backside 1B by the topsheet area. .

  As shown in FIG. 2, the topsheet 1 has a top portion 5 having a space between two layers of nonwoven fabrics 7, 7 '. In the surface sheet 1 of the present embodiment, as shown in FIGS. 1 to 3, a large number of flange portions 2 and groove portions 4 are alternately arranged, and openings 2 are formed in the groove portions 4. 2 has the top 5. Between the mutually adjacent groove parts 4, it is curved in a convex shape so as to have a top part 5. The top portion is the highest position between adjacent openings in any direction in the planar direction of the top sheet (for example, the direction in which the line AA in FIG. 1 extends).

  In the surface sheet 1 of this embodiment, as shown in FIG. 3, it is preferable that the top part continues continuously and forms the collar part. In the surface sheet 1 shown in FIG. 3, a plurality of the top portions are continuously connected substantially linearly to form multi-row flange portions 2, 2, and between the adjacent flange portions 2, 2. It becomes the groove part 4, The said collar part 2 and the said groove part 4 are alternately arranged so that it may not have a plane part. And the said collar part 2 is curving convexly, and the said groove part 4 is curving concavely, and the said groove part 4 has many said opening 6,6, ... arrange | positioned at predetermined intervals. ing. In this way, by forming the flange portion 2 and the groove portion 4, bending characteristics (for example, bulk softness) in a direction parallel to the flange portion 2 and the groove portion 4 and a direction perpendicular thereto are different. It is preferable because it can impart directionality and can further improve the fit and texture of the topsheet 1 to the body. The arrangement pattern of the openings 6, 6,... In the groove 4 is not particularly limited, and for example, a staggered arrangement pattern as shown in FIG. In this case, the distance N between the openings 6 and 6 along the groove 4 is preferably 0.4 to 40 mm, and more preferably 1.5 to 8 mm.

  In the surface sheet 1 of this embodiment, as shown in FIGS. 1 to 3, the flanges 2 and the grooves 4 are alternately arranged, and the grooves 4 are formed by a continuous surface from the flange 2. Has been. As shown in FIG. 1, it is preferable that the space | interval L between the said collar parts 2 adjacent is 1.0-6.0 mm, and it is still more preferable that it is 1.7-3.7 mm. Similarly, the interval M between the adjacent groove portions 4 is preferably 1.0 to 6.0 mm, and more preferably 1.7 to 3.7 mm.

  In the topsheet 1 of the present embodiment, the height of the top 5 between the openings 6 and 6 adjacent in a certain direction in the plane direction (for example, the height of the position of P in FIG. 1), and the direction The height of the top 5 between the adjacent openings 6 and 6 in different directions (for example, the height of the position of Q in FIG. 1) is different. When it has several top parts from which height differs like this surface sheet 1, it is preferable that the top part with the highest height is the top part 5 which has a space between two layers.

As shown in FIGS. 2 and 3, in the topsheet 1 of the embodiment, the upper layer nonwoven fabric 7 and the lower layer nonwoven fabric 7 ′ are separated from each other at the top of the collar portion 2, and the tops are both nonwoven fabrics. The top 5 has a space between 7 and 7 '.
In the top portion 5, the diffusion of the liquid at the interface between both nonwoven fabrics 7 and 7 ′, which will be described later, is suppressed, and body fluid such as menstrual blood supplied on the top sheet 1 can be prevented from spreading and conspicuous over a wide range. it can. As described above, in the topsheet 1 of the present embodiment, there are top portions having different heights, and at any top portion, a space may be formed between the two nonwoven fabrics 7 and 7 '. It is preferable that a space is formed between the two nonwoven fabrics 7 and 7 'only at the top (Q) from the viewpoint of promoting liquid diffusion in the longitudinal direction and increasing the absorbability.
Moreover, it is more preferable that the periphery of the opening 6 is substantially surrounded by the top portion 5 having a space inside regardless of the arrangement pattern. As shown in FIG. 4, the separation distance H between the nonwoven fabrics 7 and 7 ′ at the top 5 is preferably 0.05 to 1 mm, and more preferably 0.1 to 0.5 mm.

On the other hand, as shown in FIG.2 and FIG.3, in the peripheral part 61 of the opening 6, the upper nonwoven fabric 7 and the lower nonwoven fabric 7 'are in contact.
In this specification, “the state in which two layers are in contact with each other” means that at least some of the fibers constituting the upper fiber layer and the lower fiber layer maintain the form of the fibers and the two fiber layers are in contact with each other. The fibers that make up both fiber layers have a continuity that allows the liquid to pass from the part where contact begins to the end of the hole in the state where the fibers are in contact with each other while maintaining the fiber form. It is preferable that it is formed. In addition, the state in which the form of the fiber is maintained includes a case where a part of the fiber is formed into a film to the extent that the passage of the liquid is not inhibited.
The two fiber layers that are in contact with each other at the peripheral edge of the opening have (a) mechanical intertwining between the fibers constituting one fiber layer and the fibers constituting the other fiber layer, or (b) Thermally softens and melts to maintain contact. Moreover, in order to improve the contact state of a nonwoven fabric, you may adhere | attach partially with the adhesive agent.

  Both the nonwoven fabrics 7 and 7 ′ at the peripheral edge 61 of the opening 6 are formed on the inner surface side of the cylindrical portion or the inverted conical portion formed by the lower layer nonwoven fabric 7 ′, or the cylindrical portion or the cylindrical portion formed by the upper layer nonwoven fabric 7. It is preferable that the inverted conical part is fitted and integrated.

The upper non-woven fabric 7 and the lower non-woven fabric 7 'are 0.02 to 1.5 mm from the peripheral edge 62 of the aperture 6, and further 0.05 to 1 mm, particularly 0.1 to 0.3 mm in length. It is preferable that it is in contact with the skin because the contact with the skin is soft (the cushioning property is high), the dry feeling is excellent, and the transition of the liquid to the absorber is good. The length here is the length measured along the interface between the two in the vertical cross section of the topsheet.
Further, as shown in FIG. 2, the separation distance between the upper nonwoven fabric 7 and the lower nonwoven fabric 7 ′ gradually decreases from the top 5 toward the peripheral edge 61 of the opening 6, indicating that the cushion effect and the liquid It is preferable from the point of increasing absorbability.

The two nonwoven fabrics 7 and 7 ′ in the top sheet 1 of the present embodiment are each made hydrophilic by using a hydrophilic treatment agent. As used herein, the hydrophilic treatment agent includes a surface-attached treatment agent (such as a fiber oil agent) that adheres to the fiber surface, a kneading-type treatment agent that is kneaded into the fiber, and a treatment that adheres to the fiber surface. Any of the surface-fixing type processing agents in which a part of the processing agent is embedded and fixed in the fiber by heat treatment or the like is included. Also, a plurality of types of treatment agents may be applied to a single nonwoven fabric.
For the upper layer nonwoven fabric 7, it is preferable to use a surface adhesion type treatment agent, and for the lower layer nonwoven fabric 7 ', both the surface adhesion type and the kneading type are preferably used.
Different hydrophilic treatment agents are used for the upper nonwoven fabric 7 and the lower nonwoven fabric 7 ′, so that the lower nonwoven fabric (lower fiber layer) 7 ′ is different from the upper nonwoven fabric (upper fiber layer) 7. However, a change in the surface tension of the liquid due to the contact of the liquid tends to occur.
Here, the change in the surface tension of the liquid is indicated by the diffusion of the liquid at the portion where the upper fiber layer and the lower fiber layer are in contact (mainly the peripheral edge of the opening), but the liquid is a non-woven fiber. When the fiber oil agent adhering to the fiber surface dissolves in the liquid when it comes into contact with the surface, the surface tension of the liquid is reduced, so that the liquid itself is easily compatible with the hydrophobic material and difficult to be compatible with the hydrophilic material. Is shown. In this invention, it is a function of the fiber oil agent mainly used for the nonwoven fabric or web which comprises a lower fiber layer. On the other hand, since the durable fiber oil agent, ie, the fiber oil agent with low solubility with respect to the liquid, is used for the nonwoven fabric or web constituting the upper fiber layer, the change in the surface tension of the liquid is reduced.

Examples of the configuration in which the lower layer nonwoven fabric 7 ′ is more likely to change the surface tension of the liquid due to liquid contact than the upper layer nonwoven fabric 7 include the following cases. The same can be said for the case where a non-woven fabric web is used as the upper fiber layer and / or the lower fiber layer.
(1) A surface-attached hydrophilic treatment agent (fiber oil or the like) is used for both the upper nonwoven fabric 7 and the lower nonwoven fabric 7 ′, but the lower nonwoven fabric 7 ′ is more durable than the upper nonwoven fabric 7. When a low processing agent (a processing agent that dissolves easily in the liquid) is used.
(2) When a kneading type hydrophilic treatment agent is used for the fibers of the upper nonwoven fabric 7 and a surface adhesion type hydrophilic treatment agent is used for the fibers of the lower nonwoven fabric 7 ′. In this case, it is considered that the kneading type has a stronger affinity with the resin used in the fiber (due to the semi-compatibility that dissolves in the resin in the molten state but does not dissolve in the resin below the melting point). It exhibits lower solubility than the fibers of the lower layer nonwoven fabric 7 ′.
(3) A case where a surface-adhesive hydrophilic treatment agent is used after the corona treatment is applied to the fibers of the upper nonwoven fabric 7 in advance, and a surface-adhesive hydrophilic treatment agent is used for the fibers of the lower nonwoven fabric 7 ′.
(4) The hydrophilic treatment agent is embedded in the fibers of the upper nonwoven fabric 7 by heat treatment (two-step heat treatment; fixing to the fiber surface by the first treatment, and the hydrophobic resin is embedded in the hydrophobic portion by the second treatment). When a surface-adhesive hydrophilic treatment agent is used for the fibers of the nonwoven fabric 7 ′.
Among the above (1) to (4), (1) and (3) are preferable, and (1) is more preferable from the viewpoint of high applicability of the hydrophilic treatment agent and variation in surface treatment. In the above four examples, the surface-attached type is used for the processing of the fibers of the lower layer nonwoven fabric, but within the range of higher solubility than the upper layer nonwoven fabric, And you may fix a hydrophilic treatment agent by the method similar to the fixing method of the hydrophilic treatment agent with respect to the fiber of the upper layer nonwoven fabric in (3).

As surface-adhesive treatment agents (fiber oil agents, etc.), cationic, anionic, and amphoteric surfactants are used as hydrophilic treatment agents, and the main chain structure is hydrocarbon-based, silicon-based, or olefin oxide. Etc.
As a highly durable surface adhesion type treatment agent used for the upper nonwoven fabric, it is preferable from the viewpoint of hydrophilicity and durability to use a cationic hydrocarbon type (20 to 40 carbon atoms), an oligomer type olefin oxide or the like.

  As the kneading type treatment agent, the same one as the surface adhesion type treatment agent can be used, but oligomer-type olefin oxide, silicon main chain type, and the like are preferable because semi-compatibility is easily realized.

The method of using a surface-adhesive hydrophilic treatment agent for a nonwoven fabric is a dipping method (soaking) in the fiber state before making the nonwoven fabric, even if it is attached to the fibers after making the nonwoven fabric by spraying, coating, etc. It may be attached by using a method.
The amount of the surface-attached treatment agent used is not particularly limited, but is, for example, about 0.05 to 0.5 wt%. The amount of the kneading-type hydrophilic treatment agent used is not particularly limited, but is, for example, about 1 to 10 wt%.

As the nonwoven fabrics 7 and 7 ′ constituting the top sheet 1, conventionally known nonwoven fabrics can be used without any particular limitation. For example, various non-woven fabrics such as non-woven fabric, spunbonded non-woven fabric, melt blown non-woven fabric, spunlace non-woven fabric and needle punched non-woven fabric manufactured by the card method can be appropriately selected according to 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. From the viewpoint of touch and liquid absorbency, it is preferable that the upper layer nonwoven fabric 7 is made of non-woven fabric obtained by air-through method using fibers formed by the card method or air lay method, and the lower layer nonwoven fabric 7 ′ has a web method by card method. It is particularly preferable to use a non-woven fabric made by an air-through method or a spunbonded non-woven fabric.
In the present invention, as the upper fiber layer and / or the lower fiber layer, a non-woven fabric web can be used. For webs that have not been made into non-woven fabrics, fiber removal is performed by the card method, and a fiber layer is formed only by entanglement between fibers, and the subsequent non-woven fabric forming process (for example, spunlace method, needle punch method, air-through method, etc.) A web or the like obtained without passing can be used. In the present specification, the “nonwoven fabric” includes not only a single nonwoven fabric but also a laminated nonwoven fabric obtained by combining and integrating the nonwoven fabrics.

Examples of fibers used for the nonwoven fabrics 7 and 7 'include synthetic fibers such as polyesters such as polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET), and polyamides such as nylon, rayon and cupra. Examples thereof include, but are not limited to, regenerated cellulose fibers and natural fibers such as cotton. In addition, a core-sheath fiber using a fiber having a high melting point as a core and a fiber having a low melting point as a sheath, or a composite fiber such as a side-by-side fiber, a split fiber, or the like is also preferably used. These fibers can use 1 type (s) or 2 or more types. As a fiber in the case of using a non-woven fabric web for the upper fiber layer or the lower fiber layer, the same fibers as in the case of the nonwoven fabric can be used.
The upper layer nonwoven fabric 7 and the lower layer nonwoven fabric 7 ′ may be the same or different. Further, the fibers constituting the upper layer nonwoven fabric 7 and the fibers constituting the lower layer nonwoven fabric 7 ′ may be the same or different.

The top sheet 1 of the present embodiment is a top sheet of an absorbent article comprising a liquid permeable top sheet, a liquid impervious (including poorly permeable) back sheet, and an absorber disposed therebetween. Are particularly preferably used. In the case of incorporating the topsheet 1 of this embodiment into an absorbent article, the surface 8A side is used as a surface in contact with the skin, and the backside is used facing the absorber.
In addition, in the surface sheet 1 of this embodiment, the direction of the collar part 2 and the groove part 4 does not need to correspond with the longitudinal direction and transverse direction of the absorbent article in which the surface sheet 1 of this embodiment is used. For example, even if the direction of the collar part 2 and the groove part 4 is the longitudinal direction of the absorbent article, there is no problem and it can be suitably used. Similarly, even if the direction perpendicular to the flange portion 2 and the groove portion 4 is the longitudinal direction of the absorbent article, there is no problem and it can be suitably used. Further, the lower fiber layer located on the back surface side of the top sheet is not directly in contact with the absorber, and the absorber is interposed between the top sheet and the back sheet through an intermediate sheet made of nonwoven fabric or absorbent paper. Can be provided.

  In the surface sheet 1 of the present embodiment, as shown in FIG. 4, a body fluid such as menstrual blood supplied from the surface side 1 </ b> A of the surface sheet 1 mainly passes from the opening 6 directly to the absorber (arrow). A route indicated by A), a route passing from the top 5 to the absorbent body through the upper nonwoven fabric 7 (route indicated by the group of arrows B), and an opening peripheral edge from the top 5 passing through the upper nonwoven fabric 7 It moves to 61, and it transfers to an absorber rapidly by the path | route (path | route shown by the arrow C group) which transfers to the absorber 4 through the interface between both the nonwoven fabrics 7 and 7 'in an opening peripheral part 61. FIG. Furthermore, in the top portion 5, after the transition from the upper nonwoven fabric 7 to the lower nonwoven fabric 7 ′, the inner nonwoven fabric 7 ′ is transferred to the perforated peripheral edge 61, and both the nonwoven fabrics 7, 7 in the perforated peripheral edge 61 are transferred. There is also a path (path indicated by the arrow D group) that moves to the absorber 4 through the interface between '.

  In the surface sheet 1 of the present embodiment, different hydrophilic treatment agents are used for the two layers of nonwoven fabric, and the lower layer 7 'nonwoven fabric is more likely to cause a change in the surface tension of the liquid due to liquid contact than the upper layer nonwoven fabric 7. Therefore, the diffusibility (moving speed) of the liquid at the interface between both nonwoven fabrics is remarkably improved as compared with the case where the ease of occurrence of the change in the surface tension of the liquid is not different. Therefore, in particular, the liquid quickly moves along the path indicated by the arrow C group and the path indicated by the arrow D group, and the liquid supplied onto the top sheet 1 quickly moves to the absorber. On the other hand, since a space is formed between the upper and lower nonwoven fabrics 7 and 7 ′ at the top 5, the diffusion of the liquid through the interface of the nonwoven fabric is suppressed near the top, thereby supplying the surface to the surface. It is possible to prevent the body fluid such as menstrual blood from spreading and conspicuous over a wide range.

  The reason why the interface between the nonwoven fabrics quickly diffuses at the peripheral edge 61 of the opening 6 is that the liquid that has passed through the upper nonwoven fabric 7 in the opening peripheral edge 61 is a highly durable hydrophilic treatment agent. Therefore, although the change of the property (surface tension) of the liquid is small, the surface tension of the liquid is lowered by contacting the lower layer nonwoven fabric at the peripheral edge of the hole. The decrease in the surface tension of the liquid decreases the compatibility with the hydrophilic material as the compatibility with the hydrophobic material increases. For this reason, the liquid whose surface tension has changed is more compatible with the lower nonwoven fabric whose hydrophilicity has decreased due to contact with the liquid than the upper nonwoven fabric in which the hydrophilic surface is maintained. The diffusibility of the liquid increases at the boundary of the nonwoven fabric. This phenomenon is considered that the liquid gradually enters the lower layer from the upper layer side surface of the lower layer over time. Therefore, since the boundary between the upper layer nonwoven fabric and the lower layer nonwoven fabric is the narrowest region between the fibers, it is estimated that the liquid quickly diffuses at the boundary. Note that this assumption can be presumed to be the same when the liquid is led to the upper layer near the top 5 → the lower layer near the top 5 → the peripheral edge of the hole.

  Furthermore, according to the surface sheet 1 of the present embodiment, the liquid that has moved to the aperture peripheral edge 61 is not noticeable even when viewed from the surface side 1A because the aperture 6 is a three-dimensional aperture, and the top 5 The presence of the space also has an effect that the liquid transferred to the absorbent body and the lower layer nonwoven fabric is less likely to return to the upper layer nonwoven fabric of the top portion 5.

  In addition, from the viewpoint of improving the liquid diffusibility at the interface between the upper and lower nonwoven fabrics, the constituent fibers of the nonwoven fabric are not formed into a film, but are deformed so as not to leave the original fiber shape and the inter-fiber spaces are formed narrow Preferably, it is composed of a core-sheath structure type fiber and an eccentric type fiber, or a polyethylene fiber is combined with a polyester or polyethylene single fiber as a binder component, and a resin having a melting point higher than that of the binder component may be blended. preferable.

Next, the preferable method for manufacturing the surface sheet 1 of this embodiment is explained in full detail.
The surface sheet of this embodiment can be manufactured by superimposing two nonwoven fabrics and mechanically opening the holes. More specifically, after laminating the two nonwoven fabrics unwound from the raw fabric roll, the laminated nonwoven fabric is interposed between the first stamping die and the second stamping die to have the above structure. A surface sheet can be manufactured. The first pressing die is composed of a pin roll having a large number of pyramidal or conical convex pins in a row along the conveying direction of the nonwoven fabric, and the rows are arranged in multiple rows. The second pressing die is constituted by a protruding roll having a protruding portion that fits between the multi-row convex pins in the first first pressing die. A stamping die having such a configuration is described in Japanese Patent Application Laid-Open No. 6-330443 related to an earlier application of the present applicant.

  In this manufacturing method, the pin roll has the convex pins arranged in a row along the transport direction of the nonwoven fabric, and the rows are arranged in multiple rows. On the other hand, the protruding portion of the protruding roll is fitted between the rows of convex pins of the pin roll. As a result, a ridge 6 having a continuous top 5 is easily formed by the ridge portion of the ridge roll, and the opening 6 is formed by penetration of the convex pin in the pin roll into the upper and lower nonwoven fabrics. In this case, since the pin roll is heated to such an extent that it does not form a film, the pin roll is heated to a temperature lower than the resin component of the fiber (a temperature lower than the high melting point component when a plurality of resins are used for the nonwoven fabric). The nonwoven fabric of the upper and lower layers in a peripheral part is piled up, and it inserts between a convex pin roll and a hollow roll with the upper nonwoven fabric as a convex pin roll side. At this time, at least the constituent fibers of the lower-layer nonwoven fabric are integrated while preventing the whole from forming a film.

  In addition, in order to form the top part 5 having a space between the upper and lower layers of nonwoven fabric, the lower layer nonwoven fabric is previously provided with a concavo-convex shape extending in the longitudinal direction, or partially provided with a concave shape or a convex shape, etc. The strain applied to the non-woven fabric during the formation of holes is opened by a method that forms a part that does not come into contact with the surface, a method that lowers the stretchability of the lower layer nonwoven fabric from the upper layer by embossing, etc. It can be formed by a method of relaxing after formation. Moreover, space can be formed by heating an empty roll, fixing the thickness of the lower layer nonwoven fabric in a top part in the state at the time of opening, and recovering thickness other than the top part of a lower layer nonwoven fabric. In this case, the lower layer nonwoven fabric is preferably a bulky nonwoven fabric such as an air-through nonwoven fabric or an airlaid nonwoven fabric.

As mentioned above, although the surface sheet of this invention was demonstrated based on the preferable embodiment, the surface sheet of this invention is not restrict | limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention.
For example, as shown in FIG. 5, the top sheet 5 of the absorbent article of the present invention may be one in which the tops 5 between the openings 6 are not continuously formed in one direction. In the topsheet 1 ′ shown in FIG. 5, the tops 5 and the apertures 6 are arranged in a staggered manner. In the surface sheet 1 ′, a plurality of convex portions 2 ′ having a plurality of apertures 6 (four in the illustrated example) arranged around the top sheet 1 ′ are formed. A top portion 5 having a space between the lower fiber layer is formed. In the surface sheet 1 ′, there are two adjacent apertures 6 in which a convex portion 2 ′ is formed between the two and a relatively flat portion between the two, but the convex portion 2 ′ is formed. A space between the upper and lower nonwoven fabrics is formed at the top of the convex portion 2 ′ between the open holes 6.

FIG. 6 is a view showing a surface sheet according to still another embodiment of the present invention. Like the surface sheet shown in FIG. 5, the top 5 is not continuous in any direction parallel to the surface of the surface sheet. .
In the top sheet 1 ″ shown in FIG. 6, at the top 5, the lower nonwoven fabric 7 ′ is partially in contact with the upper nonwoven fabric 7 at a plurality of contact points 9 dispersed in the plane direction. As an example of a preferable arrangement of 9, there is a form in which a contact point is arranged at the center point of a regular polygon such as a regular triangle or a square and each corner of the regular polygon. According to the surface sheet, liquid transfer from the upper nonwoven fabric 7 at the top to the lower nonwoven fabric 7 ′ occurs via the contact point 9, and the liquid in the path indicated by the D group in FIG. Migration occurs more efficiently.
About the surface sheet shown in FIG.5 and FIG.6, the point which is not demonstrated especially can be made to be the same as that of said surface sheet 1. FIG. The surface sheet of the embodiment shown in FIG. 6 is formed, for example, on a nonwoven fabric for a lower layer by forming a convex portion projecting on one side by embossing or the like, and then overlapping with a separately manufactured nonwoven fabric to form an opening integrally with both. It is obtained by doing.

Either one or both of the two nonwoven fabrics in the surface sheet of the present invention may be a laminated nonwoven fabric obtained by laminating a plurality of nonwoven fabrics. Moreover, the opening need not be provided on the entire surface sheet, and may be provided only in a predetermined region. Further, the arrangement of the apertures is not limited to a staggered pattern, but may be a lattice pattern or other arrangements.
The absorbent article using the surface sheet of the absorbent article of the present invention is not limited to a sanitary napkin. Examples of other absorbent articles include panty liners, incontinence pads, disposable diapers, hygiene pads, nursing pads, and the like.

It is a top view which expands and shows the principal part of one Embodiment of the surface sheet of the absorbent article of this invention. It is a fragmentary sectional view along the AA line in FIG. It is a perspective view of the surface sheet of embodiment shown in FIG. It is a schematic cross section explaining the effect of the surface sheet shown in FIG. It is a perspective view which shows other embodiment of this invention. It is sectional drawing which shows other embodiment of this invention.

Explanation of symbols

1,1 ', 1 "Top sheet 2 Gutter part 4 Groove part 5 Top part 6 Open hole 61 Peripheral edge part 7 Open side nonwoven fabric (upper fiber layer)
7 'Non-woven fabric on the back side (lower fiber layer)
1A Front side 1B Back side

Claims (4)

A surface sheet of an absorbent article having a large number of apertures,
The top sheet has a two-layer structure of an upper fiber layer located on the front surface side and a lower fiber layer located on the back surface side, and the holes extend from the front surface side to the back surface side of the top sheet. Formed by the two layers coming out,
Having a top part having a space between the two layers, the two layers in the peripheral part of the opening being in contact with each other;
A different hydrophilic treatment agent is used for the two layers, and the lower fiber layer is more susceptible to changes in the surface tension of the liquid due to contact with the liquid than the upper fiber layer. Surface sheet.  The top sheet of an absorbent article according to claim 1, wherein a hydrophilic treatment agent having a lower liquid durability than the upper fiber layer is used for the lower fiber layer.   The top sheet of an absorbent article according to claim 1 or 2, wherein a plurality of flanges and grooves are alternately arranged, the opening is formed in the groove, and the top is formed in the flange. The top sheet of an absorbent article according to claim 1 or 2, wherein a plurality of convex portions each having a plurality of openings are formed around the perforations, and the top portions are formed on the convex portions.