JP4804337B2 - Top sheet for absorbent article and method for producing the same - Google Patents

Description

  The present invention relates to a surface sheet suitably used for a skin contact surface of an absorbent article such as a disposable diaper, a sanitary napkin, a panty liner (corimono sheet), an incontinence pad, and the like, and a method for producing the same.

As surface sheets, such as a disposable diaper and a sanitary napkin, what formed the unevenness | corrugation in the surface contact | abutted to a wearer's skin is used widely. According to the surface sheet having unevenness, the contact area with the wearer's skin is reduced due to the presence of the unevenness, so that it is possible to reduce stickiness and stuffiness.
As a surface sheet having irregularities, for example, a surface sheet is known in which a thick sheet material is integrated with another sheet material by embossing, the embossed compression portion is a recess, and the other portion is a protrusion.
Patent Document 1 describes a surface sheet in which two nonwoven fabrics are partially heat-sealed and discontinuous convex portions are formed on one nonwoven fabric other than the heat-sealed portion.

JP 2004-174234 A

In the above-described surface sheet in which the embossed compression part is a concave part and the other part is a convex part, the performance of the convex part that can be designed is limited depending on the characteristics of the sheet material.
Moreover, since the inside of a convex part is a cavity in the surface sheet of patent document 1, the improvement of the draw-in property of a liquid is desired, and also keeps highly viscous substances, such as menstrual blood and stool, away from a wearer's skin quickly. There was room for improvement.

  Accordingly, an object of the present invention is to provide a top sheet for absorbent articles that is excellent in liquid drawability and that can quickly separate highly viscous substances such as menstrual blood and stool from the skin of the wearer and its efficiency. Is to provide a practical manufacturing method.

  This invention is a surface sheet used for the skin contact surface of an absorbent article, Comprising: The 1st nonwoven fabric and the 2nd nonwoven fabric which were mutually laminated | stacked are heat-bonded partially, and the heat-fusion part is formed. In the first non-woven fabric, the portions other than the heat-sealed portion protrude toward the wearer's skin to form a large number of convex portions, and the convex portions and the heat-sealed portions alternately and form a line. And the rows are arranged in multiple rows, and at least some of the convex portions are at one end portion or both end portions in the fiber orientation direction of the first nonwoven fabric, and the fiber density of the central portion in the fiber orientation direction The object is achieved by providing a topsheet having a sparse fiber portion having a lower fiber density.

  The present invention is a method for producing the surface sheet in which no cavity is formed between the first nonwoven fabric and the second nonwoven fabric in the portion having the convex portion, and includes a crimped eccentric core-sheath composite fiber A second roll having a first surface of the first nonwoven fabric subjected to bulk recovery treatment with hot air, and a peripheral surface having a concave and convex shape that is meshed with the first roll and the concave and convex shape of the first roll. And the concave and convex shapes, and then joined with the second nonwoven fabric under the condition of being held on the peripheral surface of the first roll, together with the convex portion of the first roll and the like together with the second nonwoven fabric. A method for producing a surface sheet is provided in which the heat-sealed portion is formed by heating and pressurizing the roll.

  The present invention is a method for producing the surface sheet in which no cavity is formed between the first nonwoven fabric and the second nonwoven fabric in the portion having the convex portion, and includes a crimped eccentric core-sheath composite fiber The first nonwoven fabric is subjected to bulk recovery treatment with hot air, the peripheral surface has an uneven shape, and is adsorbed to the peripheral surface of the roll having suction holes in the concave portion, and is held on the peripheral surface of the roll. The manufacturing method of the surface sheet which joins with a nonwoven fabric and pressurizes and heats between the convex part of this roll and another roll with this 2nd nonwoven fabric, and forms the said melt | fusion part is provided.

  The present invention is a method for producing the surface sheet in which a cavity is not formed between the first nonwoven fabric and the second nonwoven fabric in the portion having the convex portion, and the first nonwoven fabric containing the heat-extensible fibers is The first roll having a concavo-convex shape on the surface and the concavo-convex shape meshing with the concavo-convex shape on the first roll are engaged with a second roll having a peripheral surface to engage with the second roll. Shaped and joined with the second nonwoven fabric under the condition of being held on the peripheral surface of the first roll, and heated and pressurized between the convex portion of the first roll and the other rolls together with the second nonwoven fabric. After forming the said heat-fusion part, heat processing is performed and the manufacturing method of the surface sheet which extends the said heat | fever extensible fiber is provided.

  The present invention is a method for producing the surface sheet in which a cavity is not formed between the first nonwoven fabric and the second nonwoven fabric in the portion having the convex portion, and the first nonwoven fabric containing the heat-extensible fibers is The surface has an uneven shape, is adsorbed on the peripheral surface of the roll having suction holes in the concave portion, and merges with the second non-woven fabric under the state of being held on the peripheral surface of the roll, together with the second non-woven fabric, the roll A method for producing a surface sheet is provided, in which after forming the fused portion by pressurizing and heating between the convex portion and other rolls, heat treatment is performed to stretch the thermally extensible fiber. .

  The surface sheet for absorbent articles of the present invention is excellent in liquid drawability and can quickly pull away highly viscous substances such as menstrual blood and stool from the skin of the wearer.

The present invention will be described below based on preferred embodiments with reference to the drawings.
FIG. 1 is a perspective view showing an embodiment of a surface sheet for absorbent articles of the present invention.
A surface sheet 10 shown in FIG. 1 is used for a skin contact surface of an absorbent article such as a disposable diaper, a sanitary napkin, a panty liner (corimono sheet), and an incontinence pad.

  The top sheet 10 is composed of a first nonwoven fabric 1 and a second nonwoven fabric 2 laminated together. The 1st nonwoven fabric 1 forms the surface (skin contact surface) which faces the wearer's skin side in the surface sheet 10, and the 2nd nonwoven fabric 2 is the surface (the surface sheet 10) which faces the absorber side ( Non-skin contact surface).

  The 1st nonwoven fabric 1 and the 2nd nonwoven fabric 2 are partially heat-sealed, and, thereby, many heat-fusion parts 4 are formed in the surface sheet 10. FIG. In the first nonwoven fabric 1, the portions other than the heat-sealing portion 4 protrude toward the wearer's skin to form a large number of convex portions 5.

  As shown in FIG. 1, the convex portions 5 and the heat fusion portions 4 are arranged alternately and in a line in the X direction, which is one direction parallel to the surface of the topsheet 10. Are formed in multiple rows in the Y direction perpendicular to the X direction. The convex portions 5 and the heat fusion portions 4 in the rows adjacent to each other are each shifted in the X direction, and more specifically, are shifted by a half pitch.

  The X direction in the topsheet 10 of this embodiment is the same direction as the orientation direction (fiber orientation direction) of the constituent fibers of the first nonwoven fabric 1. Usually, in the nonwoven fabric, the fibers are generally oriented in the flow direction (machine direction) of the web or the nonwoven fabric during the production process. The fiber orientation direction of the first nonwoven fabric 1 or the like is the same as the machine direction in the flow direction of the web or nonwoven fabric at the time of manufacture, but when the flow direction at the time of manufacture is unknown, the convex portion 5 and heat Of the direction in which the row formed by the fused portions 4 extends and the direction perpendicular thereto, the direction in which more fibers are oriented is defined as the fiber orientation direction.

In the surface sheet 10 of the present embodiment, the orientation direction (fiber orientation direction) of the constituent fibers of the second nonwoven fabric 2 is also the X direction, and the fiber orientation direction (X direction) of the first nonwoven fabric is the surface sheet 10. It also corresponds to the flow directions (see FIG. 5) of the first nonwoven fabric 1 and the second nonwoven fabric 2 in the manufacturing process. Furthermore, the fiber orientation direction (X direction) of the first nonwoven fabric preferably coincides with either the longitudinal direction (front-rear direction) of the absorbent article or the direction orthogonal thereto when the topsheet 10 is incorporated into the absorbent article. In particular, it is preferable to match the longitudinal direction of the absorbent article.
When viewed as a whole, the surface sheet 10 of the present embodiment has a substantially flat surface on the second nonwoven fabric 2 side, and has large unevenness on the surface on the first nonwoven fabric 1 side.

The inside of the convex part 5 in the surface sheet 10 is filled with the constituent fibers of the first nonwoven fabric 1 as shown in FIGS. 2 and 3. That is, the cavity is not formed between the 1st nonwoven fabric 1 and the 2nd nonwoven fabric 2 in the part which has the convex part 5 of the surface sheet 10. FIG. A cavity here is a cavity which arises between the 1st nonwoven fabric 1 and the 2nd nonwoven fabric 2, for example, the space | gap which cannot be confirmed easily when the cross section of the surface sheet 10 is observed visually, or the 1st nonwoven fabric 1 In addition, voids that are the same as or several times as large as the voids between fibers existing in the second nonwoven fabric 2 are not included in the cavities mentioned here.
The topsheet 10 of this embodiment is a liquid from the first nonwoven fabric 1 to the second nonwoven fabric 2 because no cavity is formed between the first nonwoven fabric 1 and the second nonwoven fabric 2 in the portion having the convex portions 5. It is even more excellent in migration.

As for the surface sheet 10, at least one convex part 5 has this fiber orientation direction (in the fiber orientation direction (X direction) of the 1st nonwoven fabric 1, or both ends XE and XE, as shown in FIG. A sparse fiber portion 5b having a fiber density lower than that of the central portion 5a in the X direction) is provided.
By having the sparse fiber portion 5b in the convex portion 5, a large fiber density gradient is formed between the sparse fiber portion 5b having a low fiber density and the heat fusion portion 4 or a portion located in the vicinity thereof, As a result, the liquid supplied onto the top sheet 10, in particular the liquid that flows into the concave portions between the convex portions 5, flows in the first nonwoven fabric 1 through the path shown in FIG. It smoothly transitions to the portion 4 or a portion located in the vicinity thereof. And the liquid which transferred to the heat fusion part 4 or the part located in the vicinity of it transfers to the 2nd nonwoven fabric 2, and also the absorber (not shown) distribute | arranged under it. In particular, by matching the fiber orientation direction (X direction) of the first nonwoven fabric 1 with the longitudinal direction of the absorbent article, menstrual blood flowing along the width direction of the product can be quickly absorbed from the sparse fiber portion 5b, and from the product side surface. Lateral leakage can be prevented.
In addition, high-viscosity substances such as menstrual blood and stool having a relatively high viscosity are also taken into the sparse fiber portion 5b having a low fiber density and quickly separated from the skin of the wearer.

Further, since the fiber density of the central portion 5a in the X direction of the convex portion 5 is relatively high, the top portion of the convex portion 5 becomes relatively smooth and the friction coefficient with the skin becomes relatively low. Has a smooth texture.
The convex part 5 which has the sparse fiber part 5b in the one end part XE in the fiber orientation direction (X direction) of the 1st nonwoven fabric 1 or both end parts XE and XE is a viewpoint which ensures the above effect. Therefore, it is preferably 10% or more of the total number of the convex portions 5 of the surface sheet 10, more preferably 20 to 50%, and even more preferably 30 to 50%.

FIG. 3 is a view showing a cross section along the Y direction of the same convex portion as the convex portion 5 shown in FIG.
2 and 3, the convex portion 5 has a fiber density between the center portion 5a and the sparse fiber portion 5b in the fiber orientation direction (X direction) of the first nonwoven fabric 1, as can be seen from the comparison between FIG. 2 and FIG. Is larger than the difference in fiber density between the central portion 5a and both end portions YE and YE in the direction (Y direction) perpendicular to the fiber orientation direction.
As a result, the liquid supplied onto the top sheet 10 is also taken into the top sheet 10 by a route as shown in FIG. 4B, and heat fusion in the first nonwoven fabric 1 is performed from near the top of the convex portion 5. Due to the gradient of the fiber density toward the part located in the vicinity of the attachment part 4 or in the vicinity thereof, the transition is smoothly made to the part located in the heat fusion part 4 or in the vicinity thereof. And the liquid which transferred to the heat fusion part 4 or the part located in the vicinity of it transfers to the 2nd nonwoven fabric 2, and also the absorber (not shown) distribute | arranged under it.

  Whether the first nonwoven fabric 1 has a sparse fiber portion 5b at one end XE or both ends XE, XE in the fiber orientation direction (X direction) of the first nonwoven fabric 1, and the fiber orientation direction (X direction) of the first nonwoven fabric 1 Whether the difference in fiber density between the center part 5a and the sparse fiber part 5b is greater than the difference in fiber density between the center part 5a and both end parts YE, YE in the direction (Y direction) perpendicular to the fiber orientation direction Observe the cross section in the X direction and the Y direction passing through the center point of the convex part in a plan view of the top sheet with a microscope, and check the clogging of the fibers at the center and the end in the X direction and the Y direction, respectively. Can be judged. The degree of clogging of the fibers at the center and the end in each of the X direction and the Y direction divides the portion up to about 2/3 from the top in the height direction of the convex portion into 3 or 5 equally in the X direction or Y direction, It is preferable that the degree of fiber clogging at the center and at the both ends is determined as a whole.

The convex part 5 shown in FIG.2 and FIG.3 is the fiber density of the both ends YE and YE in the direction (Y direction) orthogonal to the fiber orientation direction of the 1st nonwoven fabric 1 more than the fiber density of the center part 5a of this direction. It has become. For this reason, the liquid drawability by the route as shown in FIG. 4B is further improved.
That the fiber density of both ends YE and YE in the direction (Y direction) orthogonal to the fiber orientation direction of the first nonwoven fabric 1 is equal to or higher than the fiber density of the central portion 5a in the direction is the fibers of the both ends YE and YE. It means that the density is equal to the fiber density of the central portion 5a, or the fiber density of the both end portions YE and YE is larger than the fiber density of the central portion 5a. From the viewpoint of liquid uptake, the fiber density of the one end portion or both end portions YE, YE is preferably larger than the fiber density of the central portion 5a.

  As the first and second non-woven fabrics 1 and 2, various known non-woven fabrics can be used, for example, an air-through non-woven fabric in which heat-bonding points between fibers are formed by an air-through method on a fiber web obtained by a card method, Heat roll nonwoven fabric, heat embossed nonwoven fabric, spunbond nonwoven fabric, meltblown nonwoven fabric, spunlace nonwoven fabric, needle punched nonwoven fabric, airlaid nonwoven fabric, resin bond formed by heat roll method on fiber web obtained by card method Various nonwoven fabrics, such as a nonwoven fabric, can be used. In the topsheet 10 of the present embodiment, a nonwoven fabric that does not substantially expand and contract is used as the first and second nonwoven fabrics.

As the 1st nonwoven fabric 1, from a viewpoint of the formation nature of the convex part 5 which does not have a cavity inside, the said air through nonwoven fabric, a spunlace nonwoven fabric, a needle punch nonwoven fabric, an air laid nonwoven fabric, a resin bond nonwoven fabric etc. which are comparatively high It is preferable to use the air-through nonwoven fabric from the viewpoints of good touch and excellent thermal fusion bonding with the second nonwoven fabric.
As the second nonwoven fabric, the heat roll nonwoven fabric, the heat embossed nonwoven fabric, the spunbond nonwoven fabric, the melt blown nonwoven fabric, the spunlace nonwoven fabric and the like are particularly preferably used from the viewpoint of increasing the fiber density and facilitating the movement of the liquid from the first nonwoven fabric 1.

  As constituent fibers of the first and second nonwoven fabrics, heat-fusible fibers, particularly fibers made of a thermoplastic polymer material are preferably used. Examples of the thermoplastic polymer material include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, polytrimethylene terephthalate, and polybutylene terephthalate, and polyamides. A core-sheath type composite fiber or a side-by-side type composite fiber made of a combination of these thermoplastic polymer materials can also be suitably used. The first and second non-woven fabrics may contain, as constituent fibers, fibers that do not have heat-fusibility (for example, cotton fibers) in addition to the heat-fusible fibers.

The first nonwoven fabric 1 is preferably bulky from the viewpoint of the formability of the protrusions 5 that do not have cavities inside and from the viewpoint of quickly absorbing the liquid and quickly transferring the liquid to the second nonwoven fabric 2, and the fiber density thereof is preferably it is preferably less than 0.075 g / cm ^2, and more preferably 0.05 g / cm ² or less.
Moreover, the 1st nonwoven fabric 1 is soft and rich in cushioning property, forms the convex part 5 which is easy to deform | transform according to the movement of skin, and reduces the friction with skin and reduces the irritation | stimulation to skin, and the constituent fiber The average fineness is preferably 4.4 dtex or less, and more preferably 3.3 dtex or less.
The second non-woven fabric 2 needs to have a fiber density higher than that of the first non-woven fabric 1 from the viewpoint that the liquid needs to be drawn from the first non-woven fabric 1 by capillary force. More specifically, the fiber density is preferably 0.075 g / cm ² or more, and more preferably 0.1 g / cm ² or more.
Moreover, since the 2nd nonwoven fabric 2 needs to make fiber density higher than the 1st nonwoven fabric 1 simultaneously while providing cushioning property to a surface sheet, the average fineness of the constituent fiber is less than 3.3 dtex. It is preferable that it is 2.2 dtex or less.

From the viewpoint of more surely expressing one or more of the effects described above, the topsheet 10 preferably has the following configuration.
The thickness H (see FIG. 2) of the portion having the convex portion 5 of the surface sheet 10 is preferably 0.6 mm or more, and particularly preferably 1.0 mm or more, and the thickness h (see FIG. 2) of the heat-sealed portion 4 is 0. The thickness ratio (H / h) is preferably 2 or more, and particularly preferably 3 or more.
Further, the number of the convex portions 5 per 100 cm ^{2 of the} surface sheet 10 (regardless of the presence or absence of the sparse fiber portion 5b) is preferably 250 to 2000, and particularly preferably 500 to 1500. Moreover, it is preferable that the convex part which has the sparse fiber part 5b disperse | distributes in the surface sheet 10, and it is preferable that the number per 100 cm < ² > is 250 or more, especially 500 or more.

The bottom dimension A (see FIG. 1) of the convex portion 5 in the X direction is preferably 0.5 to 5.0 mm, particularly preferably 1.0 to 4.0 mm. The bottom dimension B (see FIG. 1) in the Y direction of the convex part 5 is preferably 1.0 to 10 mm, particularly preferably 2.0 to 7.0 mm.
The ratio of the bottom dimension A in the X direction to the bottom dimension B in the Y direction (bottom dimension A: bottom dimension B) is preferably 1: 1 to 1:10, particularly 1: 2 to 2: 5. The bottom area (bottom dimension A × bottom dimension B) of the convex portion 5 is preferably 0.5 to 50 mm ² , particularly preferably ² to 20 mm ² .
The heat-sealed portion 4 preferably has a dimension C in the X direction (see FIG. 1) of 0.1 to 2 mm, particularly preferably 0.2 to 1.0 mm, and a dimension D in the Y direction (see FIG. 1) of 0. It is preferably 2 to 5.0 mm, particularly preferably 0.5 to 3.0 mm.

Next, the preferable manufacturing method of the surface sheet 10 mentioned above is demonstrated with reference to FIG.5 and FIG.6.
In the method of the first embodiment, as the first nonwoven fabric 1, a nonwoven fabric including an eccentric core-sheath type composite fiber is used. In the eccentric core-sheath type composite fiber, the core material is unevenly present in the fiber cross section, and when heat is applied, crimp is generated due to a difference in contraction rate between the core material and the sheath material. Since the crimped eccentric core-sheath composite fiber has a three-dimensional structure, the probability that the fibers are in contact with each other in the fiber web formed after the carding process is reduced, and it is a heat fusion component. Because the sheath material is biased, a surface having a large amount of sheath components that are easily heat-sealed with other fibers in the cross-sectional direction of the fibers and a surface having few sheath components that are difficult to heat-seal are formed. It is possible to reduce the number of points, and an excellent bulk recovery property by a bulk recovery process using hot air is exhibited. Therefore, it is suitable for formation of the convex part 5 which does not have a cavity.
As the nonwoven fabric including the eccentric core-sheath type composite fiber, the air-through nonwoven fabric, the heat roll nonwoven fabric, the heat embossed nonwoven fabric, the airlaid nonwoven fabric, the resin bond nonwoven fabric, or the like is preferably used.

As the eccentric core-sheath type composite fiber, a composite fiber made of two types of thermoplastic polymer materials is preferably used. Examples of the thermoplastic polymer material include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, polytrimethylene terephthalate, and polybutylene terephthalate, and polyamides.
As the combination of the resin of the core part and the sheath part, the core part is a polyester such as polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, the sheath part is a combination of polyethylene, the core part is polypropylene, and the sheath part is polyethylene. Examples thereof include a combination, a combination of an ethylene-propylene random copolymer in the core and a polyethylene in the sheath. The ratio of the eccentric core-sheath composite fiber in the first nonwoven fabric is preferably 50 to 100%, more preferably 75 to 100%, and still more preferably 100%. As fibers other than the eccentric core-sheath type composite fiber, a heat-fusible fiber made of a single thermoplastic polymer material, cotton, or the like can be mixed.

  In the method according to the first embodiment, as shown in FIG. 5, an air-through heat treatment apparatus 6 is used for the first nonwoven fabric 1 drawn out from a roll-shaped raw fabric (not shown), and the bulk caused by hot air is used. Apply recovery processing. In the heat treatment apparatus 6 shown in FIG. 5, heat treatment using hot air is performed on the nonwoven fabric held around the peripheral surface of the drum 61. The peripheral surface of the drum 61 is made of a breathable material such as punching metal or wire mesh, and the upper portion of the drum 61 is covered with a hood 62. In the heat treatment apparatus 6, hot air is blown from the hood 62 toward the drum 61, and the blown hot air passes through the nonwoven fabric 1 and is sucked into the drum 61. The bulk recovery treatment with hot air is preferably performed by blowing hot air having a temperature lower than the melting point of the eccentric core-sheath composite fiber and a temperature equal to or higher than the melting point of −50 ° C. to the nonwoven fabric by an air-through method for 0.3 to 3 seconds. . The melting point of the eccentric core-sheath type composite fiber here is the melting point of the sheath component resin in the polymer constituting the core part and the sheath part. For example, when the sheath component of the eccentric core-sheath composite fiber is polyethylene, it is preferable to perform a recovery treatment with hot air of 90 to 110 ° C. with respect to the melting point of about 125 ° C. of the polyethylene.

  Next, the first nonwoven fabric 1 whose bulk is increased (recovered) by the above bulk recovery treatment has a meshed shape with the first roll 11 and the concave and convex shapes of the first roll 11 whose peripheral surfaces are concave and convex. The nonwoven fabric 1 is unevenly shaped by being engaged with a meshing portion with the second roll 12 having the uneven shape on the peripheral surface.

  FIG. 6 shows an enlarged view of the main part of the first roll 11. The first roll 11 is formed by combining a plurality of spur gears 11a, 11b,... Having a predetermined tooth width into a roll shape. The tooth width of each gear determines the dimension in the X direction of the convex portion 5 of the topsheet 10. Adjacent gears are combined such that the pitch of their teeth is shifted by half a pitch. As a result, the peripheral surface of the first roll 11 has an uneven shape.

  A suction hole 13 is formed in the tooth groove portion of each gear in the first roll 11. The tooth groove portion corresponds to a concave portion of the concave and convex shape on the peripheral surface of the first roll 11. The suction hole 13 communicates with a suction source (not shown) such as a blower or a vacuum pump, and performs suction between the meshing part of the first roll and the second roll and the joining part of the second nonwoven fabric 2. It is controlled to be Therefore, the non-woven fabric 1 formed with irregularities by the engagement of the first roll 11 and the second roll 12 is in close contact with the peripheral surface of the first roll by the suction force by the suction holes 13, and the irregularities are shaped. Is retained. As shown in FIG. 6, by shifting the convex portions of the adjacent gears of the roll 11 by a half pitch, a shear force is generated that tears the first nonwoven fabric 1 in the width direction between the gears. It tends to occur. By providing the gap G between the protrusions and appropriately setting the width of the gap G, the fiber density of the sparse fiber portion described above can be controlled. That is, if the gap G is small, a larger shearing force is generated, so that the fiber density of the sparse fiber portion 5b is small. If the gap G is large, the generated shearing force is small, so that the fiber density of the sparse fiber portion 5b is large.

  And as shown in FIG. 5, the 2nd nonwoven fabric 2 was made to merge with the 1st nonwoven fabric 1 in the state which sucked and held the 1st nonwoven fabric 1 on the surrounding surface of the 1st roll 11, and what overlapped them. A pressure is applied between the first roll 11 and the anvil roll 15. At this time, both the first roll 11 and the anvil roll 15 or only the anvil roll 15 are heated to a predetermined temperature. Thereby, the 1st nonwoven fabric 1 and the 2nd nonwoven fabric 2 which are located on the convex part in the 1st roll 11, ie, the tooth of each gear, are heated and pressurized, and the heat fusion part 4 is formed, The topsheet 10 having the above-described configuration is obtained.

  According to the manufacturing method of this embodiment, the surface in which no cavity is formed between the 1st nonwoven fabric 1 and the 2nd nonwoven fabric 2 in the part which has the convex part 5 by carrying out bulk recovery of the 1st nonwoven fabric with hot air. The sheet 10 can be manufactured efficiently. In addition, when the first nonwoven fabric 1 is unevenly shaped, the first nonwoven fabric 1 is stretched in the fiber orientation direction (flow direction) and in a direction perpendicular thereto, due to the low strength in the perpendicular direction. Thus, a portion having a low fiber density is generated in one or both of the left and right sides in the flow direction of the nonwoven fabric 1 of the convex portion formed in the first nonwoven fabric 1. And the surface sheet 10 which has the sparse fiber part 5b with a sparse fiber density is obtained.

Next, another method (a method according to the second embodiment) for manufacturing the top sheet 10 described above will be described with reference to FIG.
About the method of 2nd Embodiment, a different point from the method of 1st Embodiment is demonstrated, the same code | symbol is attached | subjected about the same point, and description is abbreviate | omitted. The points that are not particularly described are the same as the method of the first embodiment, and the description of the method of the first embodiment is appropriately applied.

  In the method of the second embodiment, the first nonwoven fabric 1 after being subjected to the bulk recovery treatment with hot air is adsorbed to the peripheral surface of the roll 11 having a concavo-convex peripheral surface and suction holes in the concave portion. The first non-woven fabric 1 and the second non-woven fabric 2 are joined together while the non-woven fabric 1 is continuously sucked and held on the peripheral surface of the roll 11. Then, the superposed portion is pressed and heated between the convex portion of the roll 11 and the anvil roll 15 to form the heat fusion portion 4. Thus, the surface sheet 10 having the above-described configuration is obtained. As the roll 11 in the method of 2nd Embodiment, the thing similar to the 1st roll 11 in the method of 1st Embodiment can be used.

Next, another method (a method according to the third embodiment) for manufacturing the top sheet 10 described above will be described with reference to FIG.
About the method of 3rd Embodiment, a different point from the method of 1st Embodiment is demonstrated, the same code | symbol is attached | subjected about the same point, and description is abbreviate | omitted. The points that are not particularly described are the same as the method of the first embodiment, and the description of the method of the first embodiment is appropriately applied.

In the method of 3rd Embodiment, the nonwoven fabric containing a heat | fever extensible fiber is used as a 1st nonwoven fabric. As the heat-extensible fiber, fibers composed of a first resin component and a second resin component having different orientation indexes can be used. Of these, the first resin component is a component that maintains the strength of the composite fiber, and the second resin component is a component that exhibits heat-fusibility. The first resin component preferably has an orientation index of 40% or more, more preferably 50% or more. On the other hand, the second resin component has an orientation index of preferably 25% or less, more preferably 20% or less. The orientation index is an index of the degree of orientation of the polymer chain of the resin constituting the fiber. And when the orientation index of a 1st resin component and a 2nd resin component is each said value, a heat | fever extensible composite fiber comes to expand | extend by heating. In particular, the heat-extensible conjugate fiber is preferably produced by a high-speed melt spinning method.

  Moreover, the nonwoven fabric containing a heat | fever extensible fiber is obtained, for example by forming the heat-fusion point of fibers by the air through method on the fiber web obtained by the card method. The proportion of the heat-extensible fibers in the first nonwoven fabric is preferably 50 to 100%, more preferably 75 to 100%, and still more preferably 100%.

  In the method of 3rd Embodiment, the 1st nonwoven fabric 1 containing an extensible fiber becomes the uneven | corrugated shape with the uneven | corrugated shape of the 1st roll 11 and the 1st roll 11 in which the surrounding surface is uneven | corrugated shape. The non-woven fabric 1 is unevenly shaped by being engaged with a meshing portion with the second roll 12 having an uneven shape on the peripheral surface. And the 1st nonwoven fabric 1 and the 2nd nonwoven fabric 2 are merged in the state which sucked and held the 1st nonwoven fabric 1 after uneven | corrugated shaping to the surrounding surface of the 1st roll 11, and what overlapped the 1st The 1st nonwoven fabric 1 in which the heat sealing | fusion part 4 was formed is obtained by pinching between 1 roll 11 and the anvil roll 15. FIG. In the first nonwoven fabric at this stage, a cavity is formed between the first nonwoven fabric 1 and the second nonwoven fabric 2 in the portion having the convex portion 5.

And the heat processing is given with respect to the 1st nonwoven fabric 1, the heat | fever extensible fiber in the 1st nonwoven fabric 1 is extended | stretched, and the inside of the said cavity is satisfy | filled with the heat | fever extensible fiber extended | stretched. Thus, the surface sheet 10 having the above-described configuration is obtained.
The heat treatment apparatus 6 shown in FIG. 8 is an air-through drum type heat treatment apparatus similar to the heat treatment apparatus 6 used in the first embodiment. When the heat-extensible fiber composite fiber of the present invention is a core-sheath type, the core component is polypropylene, and the sheath component is high-density polyethylene, the temperature of the hot air is 50 to 120 in the heat treatment for extending the heat-extensible fiber. The heating time is preferably 10 to 500 seconds, and particularly preferably 20 to 200 seconds.

  As described above, the surface sheet according to the present invention is preferably used as a surface sheet for absorbent articles such as disposable diapers, sanitary napkins, panty liners, and incontinence pads. Absorbent articles generally have a liquid-permeable top sheet, a liquid-impermeable or liquid-impermeable back sheet, and a liquid-retaining absorbent disposed between the two sheets.

As mentioned above, although embodiment of the surface sheet of this invention and its manufacturing method was described, each invention is not restrict | limited to said embodiment, It can change suitably. For example, the convex portion 5 of the topsheet shown in FIG. 1 has a quadrangular pyramid shape, but the convex portion 5 may have another shape such as a hemispherical shape. In addition, the degree to which the convex portions 5 and the heat-sealing portions 4 in the adjacent rows are displaced in the X direction can be set to an arbitrary size such as 1/3 pitch or 1/4 pitch instead of 1/2 pitch. can do.
Moreover, although the convex part shown in FIG.2 and FIG.3 has the sparse fiber part 5b in the both ends of the fiber orientation direction of the 1st nonwoven fabric 1, it has the sparse fiber part 5b only in one edge part. Alternatively, one surface sheet 10 may have a mixture of a sparse fiber portion 5b at both ends and a sparse fiber portion 5b only at one end. Moreover, the surface sheet which concerns on this invention may be distribute | arranged only to the site | part which opposes a part of skin contact surface of an absorbent article, for example, an excretion part. Moreover, although the convex part 5 which has the sparse fiber part 5b is distributed over the whole surface sheet, the convex part which has the sparse fiber part 5b may be distributed only in the excretion part opposing part.

FIG. 1 is a perspective view showing an embodiment of a surface sheet for absorbent articles according to the present invention. FIG. 2 is an enlarged cross-sectional view showing an enlarged cross section along the X direction of a convex portion having a sparse fiber portion in the surface sheet shown in FIG. 1. FIG. 3 is an enlarged cross-sectional view showing an enlarged cross section along the Y direction of a convex portion having a sparse fiber portion in the surface sheet shown in FIG. 1. FIG. 4 is a schematic diagram for explaining the function and effect of the top sheet for an absorbent article of the present invention. FIG. 4A corresponds to FIG. 2 and FIG. 4B corresponds to FIG. FIG. FIG. 5 is a schematic view showing a first embodiment of a method for producing a top sheet for absorbent articles of the present invention. 6 is an enlarged view of a main part of the first roll in FIG. FIG. 7 is a schematic view showing a second embodiment of a method for producing a top sheet for absorbent articles of the present invention. FIG. 8 is a schematic view showing a third embodiment of a method for producing a top sheet for absorbent articles of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Topsheet 1 1st nonwoven fabric 2 2nd nonwoven fabric 4 Thermal fusion part 5 Protrusion 5a X direction center part XE X direction end part 5b Sparse fiber part 5c Y direction center part YE Y direction end part

Claims (6)

A surface sheet used for a skin contact surface of an absorbent article,
The first nonwoven fabric and the second nonwoven fabric laminated to each other are partially heat-sealed to form a heat-sealed portion,
The first non-woven fabric has a portion other than the heat-sealed portion protruding toward the wearer's skin to form a number of convex portions,
The convex portions and the heat fusion portions are alternately and arranged in a row, and the rows are arranged in multiple rows,
At least some of the convex portions have a sparse fiber portion having a fiber density lower than the fiber density of the central portion in the fiber orientation direction at one end or both ends in the fiber orientation direction of the first nonwoven fabric,
A cavity is not formed between the first nonwoven fabric and the second nonwoven fabric in the portion having the convex portion,
The first non-woven fabric is an air-through non-woven fabric in which a heat-sealing point between fibers is formed on a fiber web obtained by a card method by an air-through method,
The 2nd roll which has the 1st nonwoven fabric containing a heat-extensible fiber in the 1st roll in which the peripheral surface is uneven | corrugated shape, and the uneven | corrugated shape which is meshed with the uneven | corrugated shape of the 1st roll in a peripheral surface. And a convex portion of the first roll together with the second nonwoven fabric under the state of being held on the peripheral surface of the first roll, A topsheet formed by heating and pressurizing with another roll to form the heat-fused portion, and then heat-treating the heat-extensible fiber . A surface sheet used for a skin contact surface of an absorbent article,
The first nonwoven fabric and the second nonwoven fabric laminated to each other are partially heat-sealed to form a heat-sealed portion,
The first non-woven fabric has a portion other than the heat-sealed portion protruding toward the wearer's skin to form a number of convex portions,
The convex portions and the heat fusion portions are alternately and arranged in a row, and the rows are arranged in multiple rows,
At least some of the convex portions have a sparse fiber portion having a fiber density lower than the fiber density of the central portion in the fiber orientation direction at one end or both ends in the fiber orientation direction of the first nonwoven fabric,
A cavity is not formed between the first nonwoven fabric and the second nonwoven fabric in the portion having the convex portion,
The first non-woven fabric is an air-through non-woven fabric in which a heat-sealing point between fibers is formed on a fiber web obtained by a card method by an air-through method,
The second nonwoven fabric is in a state in which the first nonwoven fabric containing the heat-extensible fibers is adsorbed on the circumferential surface of a roll having a concavo-convex shape in the concave portion and having suction holes in the concave portions and held on the circumferential surface of the roll. Together with the second nonwoven fabric, press and heat between the convex part of the roll and another roll to form the fused part, and then heat treatment to stretch the thermally extensible fiber. A surface sheet . The convex portion having the sparse fiber portion is a fiber at the center portion and both ends in a direction in which the fiber density difference between the center portion and the sparse fiber portion in the fiber orientation direction of the first nonwoven fabric is orthogonal to the fiber orientation direction. The surface sheet according to claim 1 or 2 , wherein the surface sheet is larger than the difference in density. 4. The topsheet according to claim 3 , wherein the convex portion having the sparse fiber portion has a fiber density at both ends in a direction orthogonal to a fiber orientation direction of the first nonwoven fabric equal to or higher than a fiber density at a center portion in the direction. . Used on the skin contact surface of absorbent articles,
The first nonwoven fabric and the second nonwoven fabric laminated to each other are partially heat-sealed to form a heat-sealed portion,
The first non-woven fabric has a portion other than the heat-sealed portion protruding toward the wearer's skin to form a number of convex portions,
The convex portions and the heat fusion portions are alternately and arranged in a row, and the rows are arranged in multiple rows,
At least some of the convex portions have a sparse fiber portion having a fiber density lower than the fiber density of the central portion in the fiber orientation direction at one end or both ends in the fiber orientation direction of the first nonwoven fabric,
A method for producing a surface sheet in which no cavity is formed between the first nonwoven fabric and the second nonwoven fabric in the portion having the convex part ,
The 2nd roll which has the 1st nonwoven fabric containing a heat-extensible fiber in the 1st roll in which the peripheral surface is uneven | corrugated shape, and the uneven | corrugated shape which is meshed with the uneven | corrugated shape of the 1st roll in a peripheral surface. And a convex portion of the first roll together with the second nonwoven fabric under the state of being held on the peripheral surface of the first roll, A method for producing a surface sheet, wherein the heat-fusible portion is formed by heating and pressing with another roll, and then heat treatment is performed to elongate the heat-extensible fiber. Used on the skin contact surface of absorbent articles,
The first nonwoven fabric and the second nonwoven fabric laminated to each other are partially heat-sealed to form a heat-sealed portion,
The first non-woven fabric has a portion other than the heat-sealed portion protruding toward the wearer's skin to form a number of convex portions,
The convex portions and the heat fusion portions are alternately and arranged in a row, and the rows are arranged in multiple rows,
At least some of the convex portions have a sparse fiber portion having a fiber density lower than the fiber density of the central portion in the fiber orientation direction at one end or both ends in the fiber orientation direction of the first nonwoven fabric,
A method for producing a surface sheet in which no cavity is formed between the first nonwoven fabric and the second nonwoven fabric in the portion having the convex part ,
The second nonwoven fabric is in a state in which the first nonwoven fabric containing the heat-extensible fibers is adsorbed on the circumferential surface of a roll having a concavo-convex shape in the concave portion and having suction holes in the concave portions and held on the circumferential surface of the roll. Together with the second nonwoven fabric, and pressurizing and heating between the convex portion of the roll and another roll to form the fused portion, and then heat treating to stretch the thermally extensible fiber. The manufacturing method of a surface sheet.

Images