KR20170021791A - Non-woven fabric - Google Patents

Abstract

The present invention relates to a nonwoven fabric (1) formed of a base portion (10) widening in a planar shape and a plurality of convex portions (12) protruding from the base portion in the thickness direction (Th). Each convex portion has a convex surface portion 12T. Each convex surface portion is configured such that the fiber density of the convex surface portion is deviated in a predetermined direction out of the plane direction of the nonwoven fabric.

Description

Nonwoven {NON-WOVEN FABRIC}

The present invention relates to a nonwoven fabric in which the fiber density of the nonwoven fabric, in particular, the nonwoven fabric is biased.

Patent Document 1 discloses a nonwoven fabric sheet having a first protruding portion protruding toward the first surface side in a plan view and a second protruding portion protruding toward the second surface opposite to the first surface, The protruding portion is a nonwoven fabric which is diffused in plural alternations in two directions from the plane of the nonwoven fabric toward the first direction and the second direction, and the fiber density of the first surface side at the top of the first protrusion is smaller than that of the second surface side A nonwoven fabric having a fiber density lower than that of the nonwoven fabric is disclosed.

Patent Document 1: Japanese Patent Application Laid-Open No. 144835/1995

However, in the nonwoven fabric according to the invention disclosed in Patent Document 1, since the fibers constituting the nonwoven fabric are formed so that the fiber densities of the fibers constituting the nonwoven fabric become approximately equal to each other, the direction in which the absorbed liquid penetrates is controlled I can not. Therefore, for example, when such a nonwoven fabric is used as the topsheet of the absorbent article, a body fluid such as urine or menstrual blood, which is disposed on the nonwoven fabric, permeates the body fluids so as to spread without directivity. As a result, since the body fluids penetrate even toward the outer side of the absorbent article, the body fluids may reach the outer side of the absorbent article, and leakage may occur.

Accordingly, an object of the present invention is to provide a nonwoven fabric which allows the absorbed liquid to penetrate in a desired direction.

In order to solve the above problems, according to the present invention,

A nonwoven fabric comprising a base portion widened in a planar shape and a plurality of convex portions protruding in the thickness direction from the base portion,

Each of the convex portions has a convex surface portion,

Each of the convex surface portions is configured so that the fiber density of the convex surface portion deviates in a predetermined direction out of the plane direction of the nonwoven fabric

A nonwoven fabric can be provided.

According to the nonwoven fabric of the present invention, since the fiber density of the convex surface portion of the convex portion is biased in a predetermined direction, the absorbed liquid can penetrate in a desired direction.

1 is a plan view of a nonwoven fabric according to a first embodiment of the present invention.
Fig. 2 is a partial cross-sectional view taken along a line II-II in Fig.
3 is a view for explaining the distribution of the fiber density of the convex surface portion of the convex portion in the nonwoven fabric 1 of Fig.
Fig. 4 is a photograph of the nonwoven fabric of Fig. 1 taken in the plane of the nonwoven fabric. Fig.
5 is a photograph of an enlarged cross section of the V portion in Fig.
Fig. 6 is a view for explaining the distribution of the fiber density of the convex surface portion of the convex portion in the nonwoven fabric according to the second embodiment. Fig.
7 is a view for explaining the distribution of the fiber density of the convex surface portion of the convex portion and the base portion located around the convex portion in the nonwoven fabric according to the third embodiment.
8 is a view for explaining the distribution of the fiber density of the convex surface portion of the convex portion and the base portion located around the convex portion in the nonwoven fabric according to the fourth embodiment.
9 is a schematic view showing an outline of a manufacturing facility for manufacturing a nonwoven fabric according to an embodiment of the present invention.
10 is an enlarged view of the portion X in Fig.
11 is a view for explaining a measurement point for measuring the fiber density of the convex surface portion of the convex portion of the nonwoven fabric according to Examples 1 to 3;

(First Embodiment)

Hereinafter, the nonwoven fabric 1 according to the first embodiment of the present invention will be described with reference to Figs. 1 to 5. Fig.

Fig. 1 is a plan view of a nonwoven fabric according to a first embodiment of the present invention, and Fig. 2 is a sectional view taken along a line II-II in Fig. The nonwoven fabric 1 according to the first embodiment is widened on the plane of the nonwoven fabric 1 defined by the longitudinal direction Lo and the transverse direction Tr and has a first And has a surface FF and a second surface FS located on the opposite side.

1 and 2, the nonwoven fabric 1 has a base portion 10 widening in a substantially planar shape and a base portion 10 extending in the thickness direction Th from the base portion 10 in the first embodiment, FF projecting toward the front side of the frame. Each of the convex portions 12 includes a convex surface portion 12T spaced from the base portion 10 in the thickness direction Th of the nonwoven fabric 1. Here, the convex surface portion 12T is formed so as to have a convex surface 12T which is larger than the intermediate point between the base portion 10 and the top portion of the convex portion 12 that is most distant from the base portion 10 in the thickness direction Th, Refers to a portion of the convex portion 12 positioned on the top side of the portion 12 and forming a constant surface facing the projecting direction of the convex portion 12 from the base 10.

In the first embodiment, the convex surface portion 12T is substantially flat. However, the convex surface portion 12T need not be a perfectly flat surface but may include a certain inclined surface or a curved surface.

In addition, in the first embodiment, the convex portion 12 has an apparently cylindrical shape with a diameter of about 10 mm. In another embodiment, the shape of the convex portion 12 is a shape including a convex surface portion having a constant area such as a shape of a cone, a columnar shape of an ellipse or a polygon, and a shape of a horn.

Fig. 3 is a view for explaining the distribution of the fiber density of the convex surface portion 12T of the convex portion 12 in the nonwoven fabric 1 of Fig. 3 shows the distribution of the fiber density of the convex surface portion 12T by the density (number) of the "X" table.

3, each convex surface portion 12T is configured such that the fiber density of the convex surface portion 12T is shifted toward the longitudinal direction Lo of the nonwoven fabric 1 in the plane direction of the nonwoven fabric 1 . That is, in the convex surface portion 12T, the fiber density is high on one side in the longitudinal direction Lo and on the other side in the longitudinal direction Lo, on the predetermined line extending in the longitudinal direction Lo, There is a low portion.

In other words, in the nonwoven fabric 1 according to the first embodiment, the respective convex surface portions 12T are arranged in a direction perpendicular to the longitudinal direction Lo of the nonwoven fabric 1 as seen from the plane of the nonwoven fabric 1, Convex surface portion 121T is bisected by the two half-convex surface portions 121T and 122T so as to have the same area by the imaginary line VL extending in the transverse direction Tr, the fiber density of one half- Is higher than the fiber density of the semi-convex surface portion 122T. Here, the " fiber density of the semi-convex surface portion " refers to an average of the fiber density of the entire half-convex surface portions 121T and 122T. When measuring the fiber density as described later, Is cut in the transverse direction Tr in the direction perpendicular to the direction in which the fibers are biased, that is, in the transverse direction Tr in the case of the first embodiment, and in the direction in which the fibers are biased, that is, in the case of the first embodiment, Is divided into three equal parts in the longitudinal direction (Lo), and the fiber density measured at the central portion in the transverse direction (Tr) of these cut surfaces is averaged.

Fig. 4 is a photograph of the nonwoven fabric of Fig. 1 taken on a black stand, when viewed from the plane of the nonwoven fabric. In the photograph of Fig. 4, the shade of the color represents the high and low of the fiber density. That is, the darker the black color in FIG. 4, the lower the fiber density because the color of the photographing stand is likely to be visually seen, and the higher the white color, the higher the fiber density is because the color of the photographing stand is less visible. 4 also shows that the fiber density of the convex surface portion 12T of the convex portion 12 in the nonwoven fabric 1 according to the first embodiment is smaller than the fiber density of the convex portion 12T of the nonwoven fabric 1 It can be said that it is shifted in the longitudinal direction (Lo). This is because, when the convex surface portion 12T is observed in Fig. 4, the black color tends to be dark on one side in the longitudinal direction Lo and white tends to be dark on the other side.

On the other hand, in the present invention, when measuring the " fiber density ", the number of points (FC) at which fibers are cut per 1 mm 2 on the cut surface of the nonwoven fabric 1 is taken as an index. More specifically, by using a scanning electron microscope (e.g., " Real Surface View Microscope VE-7800 " manufactured by KEYENCE Co., Ltd.), the magnification is adjusted to about 50 to 100 times to observe a cut surface of a certain area , And counts the fiber-cut portions FC (Fig. 5) thereon. The cut surface to be observed includes the entire thickness direction Th from the first surface (FF) to the second surface (FS). Subsequently, the number of cut portions is replaced with the number per 1 mm 2, and the number is used as an index of " fiber density ".

In the first embodiment, the fibers used in the nonwoven fabric 1 are fibers of core sheath structure, and the material thereof is sheathing high density polyethylene (HDPE) and the core being polyethylene terephthalate (PET).

The fibers used for the nonwoven fabric include natural fibers, regenerated fibers (such as rayon and acetate), thermoplastic resin fibers (polyethylene, polypropylene, polybutylene, ethylene- Polyolefins such as acrylic acid copolymer and ionomer resin, polyethylene terephthalate, polyesters such as polybutylene terephthalate, polytrimethylene terephthalate, and poly lactic acid, and polyamides such as nylon) Among these, thermoplastic resin fibers or surface modifiers thereof are preferable. These fibers may be composite fibers such as core sheath type fibers, side by side type fibers, island / sea type fibers, hollow type fibers, flat type, Y type, C type Split fibers that are divided by physical loads such as three-dimensional crimped fibers of latent crimp or current crimp, water flow, heat, embossing, and the like. On the other hand, these fibers may be hydrophilic fibers or hydrophobic fibers. However, in the case of using hydrophobic fibers, it is necessary to apply the hydrophilic emulsions separately to the fibers.

1, in the nonwoven fabric 1 according to the first embodiment, the convex portions 12 are linearly arranged along the first direction D1 and the second direction D2 have. Here, the first direction D1 is the same as the transverse direction Tr, and the second direction D2 is a direction inclined by 60 占 from the first direction D1. In the nonwoven fabric 1 according to the first embodiment, the base 10 and the convex portion 12 are evenly arranged by disposing the convex portions 12 at equal intervals. Thus, when the nonwoven fabric 1 is used as the topsheet of the absorbent article such as the disposable diaper or the sanitary napkin and the first surface (FF) is used as the surface, the body fluid discharged on the non- It is possible to arrange the base portion 10 for penetrating into the inside where the absorber or the like is located and the convex portion 12 for penetrating the body fluid in a desired direction.

1, in the nonwoven fabric 1 according to the first embodiment, the convex portions 12 adjacent to each other in the first direction D1 and the second direction D2 are formed in the base 10, Are intermittently formed. As a result, the body fluids disposed on the first surface (FF) can be infiltrated in a direction in which the fiber density is biased and transferred from the convex surface portion (12T) of the convex portion (12) to the adjacent base portion (10). Thus, for example, when the nonwoven fabric 1 is used as the topsheet of the absorbent article, the liquid can be efficiently infiltrated from the base portion 10 into the absorbent article.

Now, the operation of the nonwoven fabric according to the first embodiment will be described. In the nonwoven fabric 1 according to the first embodiment, as described above, each convex surface portion 12T is formed so that the fiber density of the convex surface portion 12T is shifted in the longitudinal direction Lo of the plane direction of the nonwoven fabric 1 Respectively. Therefore, the liquid absorbed by the fibers forming the convex portions 12 is liable to penetrate from the lower fiber density toward the higher fiber density due to the capillary phenomenon, so that the fibers tend to move toward the higher fiber density in the longitudinal direction Lo. Therefore, by arranging the nonwoven fabric so that the higher fiber density side is arranged in the direction in which the liquid is desired to be infiltrated, the absorbed liquid can be infiltrated in a desired direction. In the present specification, it should be noted that " the liquid can permeate in a desired direction " means that the liquid does not penetrate only in a desired direction, but that the liquid penetrates in a desired direction increases .

On the other hand, the fiber density of the convex surface portion 12T is biased in the longitudinal direction (Lo) in the nonwoven fabric 1 according to the first embodiment, but may be shifted in any direction in the plane direction of the nonwoven fabric 1. That is, the convex surface portion 12T may be configured so that the fiber density of the convex surface portion 12T is deviated in a predetermined direction out of the plane direction of the nonwoven fabric 1. [ By arranging the side having a higher fiber density so as to face the direction in which the liquid is to be infiltrated, the liquid can be infiltrated in a desired direction.

3, the fiber distribution of the convex portion 12T of one convex portion 12 is described. However, in the nonwoven fabric 1 according to the first embodiment, the convex portion 12T of each convex portion 12 12T have the same fiber distribution as in Fig. It is not necessary that the fiber density of the convex surface portion 12T of all the convex portions 12 be deviated and the fiber density of the convex surface portion 12T of the convex portion 12 The biased nonwoven fabric 1 may be regarded as a nonwoven fabric within the scope of the present invention. This is because the effect of the nonwoven fabric 1 of the present invention, which can penetrate the liquid absorbed in the nonwoven fabric 1 in a desired direction, remains unchanged.

The degree of deflection of the fiber density of the convex surface portion 12T may be such that the liquid absorbed by the nonwoven fabric 1 can be infiltrated in a desired direction.

In the nonwoven fabric 1 according to the first embodiment, as described above, the convex portions 12 are formed in the first direction D1 and the second direction D2 inclined by 60 占 from the first direction D1 As shown in FIG. In another embodiment, the second direction D2 is inclined at an angle other than 60 占 from the first direction D1. In another embodiment, the convex portions 12 are arranged linearly only along one direction. In the other embodiments, the convex portions 12 are not disposed along any direction, but are arranged at arbitrary positions.

In the nonwoven fabric 1 according to the first embodiment, the base portions 10 and the convex portions 12 are evenly arranged by disposing the convex portions 12 at regular intervals as described above. In another embodiment, the distance between the convex portions 12 is not constant.

In another embodiment, the convex portion 12 is arranged linearly in either the first direction D1 or the second direction D2, and in another embodiment, the convex portion 12 is not disposed along any direction , Irregularly arranged.

(Second Embodiment)

Hereinafter, the nonwoven fabric 1 according to the second embodiment of the present invention will be described with reference to Fig. The second embodiment differs from the first embodiment mainly in the following points.

6 is a view for explaining the distribution of fiber density of the convex surface portion 12T of the convex portion 12 in the nonwoven fabric 1 according to the second embodiment. As shown in Fig. 6, in each convex portion 12, the edge portion 12TE of the convex surface portion 12T has a fiber density higher than that of the central portion 12TC of the convex surface portion 12T. As described above, when the fiber density of the edge portion 12TE of the convex surface portion 12T is high, the rigidity of the edge portion 12TE is increased. Thus, even when an external force is applied to the convex portion 12, 12 can be maintained. Therefore, for example, when the nonwoven fabric 1 is packaged for sale, an external force is applied to the convex portion 12 to prevent the shape of the nonwoven fabric 1 from collapsing. As a result, it is preferable that the nonwoven fabric 1 is packed and the formability is excellent even after the package is opened. The appearance of the nonwoven fabric 1 according to the second embodiment is also preferable because the shape of the convex portion 12 of the nonwoven fabric 1 can be maintained even after packaging and opening.

The edge portion 12TE is a region of the convex surface portion 12T having a constant width along the edge 12TEE of the convex surface portion 12T and in the direction of the center portion 12TC to such an extent that the fiber density can be confirmed. The center portion 12TC is a portion apart from the edge 12TE at the edge portion 12TE. On the other hand, when it is difficult to identify the marginal portion 12TE and the central portion 12TC, a certain range around the center of gravity of the geometric shape of the convex surface portion 12T viewed from the plane of the nonwoven fabric 1 is referred to as the center portion 12TC do. In the case of the second embodiment, the width of the edge portion 12TE is about 1 mm, that is, the diameter (or the length of the diameter of the convex surface portion 12T) with respect to the convex surface portion 12T having a diameter of about 10 mm, Of the total length.

On the other hand, also in the second embodiment, in the same manner as the nonwoven fabric 1 according to the first embodiment, each convex surface portion 12T is formed so that the fiber density of the convex surface portion 12T is greater than the fiber density of the nonwoven fabric 1 1 in the longitudinal direction Lo. That is, in the second embodiment, on the line extending in the predetermined longitudinal direction (Lo) from the central portion 12TC of the convex surface portion 12T, the fiber density is high at any position on one side of the longitudinal direction Lo , And a portion with a low fiber density exists at any position on the other side of the longitudinal direction Lo.

(Third Embodiment)

Hereinafter, referring to Fig. 7, the nonwoven fabric 1 according to the third embodiment of the present invention will be described. The third embodiment differs from the first embodiment mainly in the following points.

7 illustrates the distribution of the fiber density of the convex portion 12T of the convex portion 12 and the base portion 10 located around the convex portion 12 in the nonwoven fabric 1 according to the third embodiment FIG. 7, the convex surface portion 12T of the convex portion 12, which is one end in the longitudinal direction Lo of the convex surface portion 12T as seen from the plane of the nonwoven fabric 1, The fiber density is lower in the portion 10L of the base portion 10 closer to the portion 12TH where the fiber density of the constituting fibers is higher than the other portion of the base portion 10. [ That is, as the base 10 comes close to the portion 12TH having the higher fiber density of the convex portion 12 around the convex portion 12, the fiber density becomes lower.

As a result, a portion of the base 10 that is lower in density than the other portions of the base 10 is produced. Thus, for example, when the nonwoven fabric 1 according to the third embodiment is used for the topsheet of the absorbent article, the liquid that has migrated to the portion 12TH having a high fiber density of the convex surface portion 12T, It can be quickly transmitted through the portion 10L where the fiber density of the base portion 10 located in the vicinity thereof is low. As a result, the body fluid discharged on the nonwoven fabric 1 can be promptly transferred into the absorbent article provided with the absorbent body or the like.

(Fourth Embodiment)

Now, the nonwoven fabric 1 according to the fourth embodiment of the present invention will be described with reference to Fig. The fourth embodiment differs from the third embodiment mainly in the following points.

8 illustrates the distribution of the fiber density of the convex portion 12T of the convex portion 12 and the base 10 located around the convex portion 12 in the nonwoven fabric 1 according to the fourth embodiment FIG. In the nonwoven fabric according to the fourth embodiment, the edge portion 12TE of the convex surface portion 12T of each convex portion 12, as in the nonwoven fabric according to the second embodiment, The fiber density is higher than the central portion 12TC of the convex surface portion 12T. That is, the nonwoven fabric 1 according to the fourth embodiment is a nonwoven fabric having both the action effects of the nonwoven fabric 1 according to the second and third embodiments. Since these effects are the same as those of the nonwoven fabric 1 according to the second and third embodiments, the description is omitted.

(Production method of nonwoven fabric)

A method of manufacturing the nonwoven fabric 1 according to the fourth embodiment will now be described. Fig. 9 is a schematic view showing the outline of the production facility 3 for producing the nonwoven fabric 1 according to the embodiment of the present invention, and Fig. 10 is an enlarged view of the portion X in Fig. The manufacturing facility 3 is provided with a card machine 20 for carding the fibers F1 and adjusting the unit weight and for forming the fibers F2 so as to have the shape of the nonwoven fabric 1 A suction drum 22 and an air jet nozzle 26 and a heat treatment device 28 for heat treating the fiber F3 to fix the shape formed on the fiber F3. 9, the fibers F1 to F3 and the nonwoven fabric 1 to be described later are conveyed in the direction of the arrow MD and the conveying direction MD coincides with the longitudinal direction Lo of the nonwoven fabric 1. [

First, the method for manufacturing the nonwoven fabric 1 will be described. First, the fiber F1 is opened by the card machine 20, the unit weight is adjusted, and the fiber F2 after carding is fed to the suction drum 22 . Subsequently, hot air is blown by the air jet nozzle 26 while sucking and moving the fibers F2 on the outer circumferential surface of the suction drum 22 on which the pattern plate 24 is provided, whereby the nonwoven fabric 1 ) Of the fiber (F2). The nonwoven fabric 1 is completed by thermally treating the post-formed fibers F3 in the heat treatment apparatus 28 and fixing the shape of the fibers F3 formed in the previous step.

Hereinafter, a method for producing the nonwoven fabric 1 will be described in detail. In the manufacturing process of the nonwoven fabric 1, the carded fiber F1 is first fed to the card machine 20. In the card machine 20, the fiber F1 is further opened and the unit weight (basis weight) of the fiber F1 is adjusted to a desired value.

The fiber F2 that has passed through the card machine 20 is supplied to the suction drum 22. The inside of the suction drum 22 is hollow, and the inside of the suction drum 22 becomes negative pressure by sucking air by a suction means such as a blower. A large number of suction holes 22t are formed on the outer circumferential surface of the suction drum 22, so that the outside air can be sucked. On the other hand, the diameter of the suction hole of the suction drum 22 is set small so as not to attract the fibers F2 into the suction drum 22.

The outer circumferential surface of the suction drum 22 is covered by the pattern plate 24 over its entire periphery. Specifically, the fiber F2 is supplied onto the pattern plate 24. In this manufacturing method, the pattern plate 24 is a porous plate in which a through hole 24t having a shape complementary to the convex portion 12 of the nonwoven fabric 1 is formed with the distribution of the convex portion 12.

As a result, the suction hole of the suction drum 22 exposed in the through hole 24t of the pattern plate 24 sucks the fiber F2 supplied onto the pattern plate 24. On the other hand, in the nonwoven fabric 1 of the embodiment, the position of the base 10 on the first face FF and the convex surface portion 12T of the convex portion 12 in the thickness direction Th of the nonwoven fabric 1 The car is almost the same as the thickness of the pattern plate 24.

In this manufacturing method, the suction drum 22 is moved from the point SS at which the fibers F2 are transferred from the upstream belt conveyor UB to the downstream side belt conveyor DB, F2 in the area AS up to the point SE at which the fibers F2 are conveyed and to suck the fiber F2 in the other area AN. So that the efficiency of the sucking action by the suction drum 22 is improved.

The fiber F2 sucked on the outer circumferential surface of the suction drum 22 is blown out by the air jet nozzle 26. Here, the air jet nozzle 26 has a mechanism that uniformly blows a predetermined amount of warm air with a uniform width in the width direction. By adjusting the widths of these jetting ports, the distance from the jetting port to the fibers F2, and the like, the hot air is blown out evenly over the entire width of the laminate formed of the fibers F2. The fibers F2 can be formed to have the shape of the nonwoven fabric 1 according to the above embodiment by the pulling action and the flushing action by the suction drum 22 and the air jet nozzle 26. [

The temperature of the hot air blown out from the air jet nozzle 26 is adjusted to be not higher than the melting point of the fiber F2 but to prevent the nonwoven fabric 1 becoming excessively hard after completion. Further, the wind speed of the warm air is determined so as to deform the fiber F2 into a desired shape. Generally, the temperature and the wind speed of the hot air from the air jet nozzle 26 vary depending on the material and unit weight of the fiber to be used, the shape of the finished nonwoven fabric 1, and the like. . For example, the temperature of the warm air blown from the air jet nozzle 26 is preferably 80 to 400 [deg.] C, and the wind speed is preferably 10 to 200 [m / sec]. In this manufacturing method, the temperature of the hot air blown out from the air jet nozzle 26 is 180 [占 폚] and the wind speed is 38.9 [m / sec]. On the other hand, at this stage, by blowing warm air at a temperature higher than the melting point of the fiber F2, it is possible to fix the deformed shape to a certain extent while being formed on the fiber F2.

On the other hand, in the production facility 3 according to the present embodiment, the surface of the laminate formed of the fibers F2 facing the suction drum 22 and the pattern plate 24 is located on the first side (FF side) of the nonwoven fabric 1, And the surface of the laminate facing the air jet nozzle 26 becomes the second surface FS of the nonwoven fabric 1. [

When the fiber F2 is blown by the air jet nozzle 26, the fiber F2 is blown off and moves around. As a result, the amount of fibers in the blown portion is reduced, and further, the fiber density of the blown portion is lowered. On the other hand, since the air jet nozzle 26 is stationary, the fibers F2 located in the through holes 24t of the pattern plate 24 are located on the upstream side of the transport direction MD F2tu), the fiber density is lowered by finally blowing warm air. Thereafter, the fibers F2 moved by the flushing action by the air jet nozzle 26 are fixed to the position after the movement by the suction action of the suction drum 22. [ First of all, warm air is blown to the downstream portion F2td of the conveying direction MD of the fiber F2 located in the through hole 24t, and the fibers located in the portion F2td are blown out And moves to the downstream side of the transport direction MD. After that, however, hot air is blown to a portion F2tu on the upstream side of the conveying direction MD of the fiber F2 located in the through hole 24t, and the fiber moves to the downstream side in the conveying direction MD. Since the fibers F2 located in the through holes 24t of the pattern plate 24 are continuously sucked and drawn by the suction drum 22, the fibers F2 are conveyed to the subsequent process while the movement of the fibers is suppressed. As a result, finally, the fiber density of the downstream portion F2td of the fiber F2 in the conveying direction MD is increased, and on the contrary, the fiber density of the upstream portion of the fibers F2, The fiber density of the portion F2tu is lowered. As described above, in the nonwoven fabric 1, the convex surface portion 12T of each convex portion 12 is formed in such a manner that the fiber density of the convex surface portion 12T is set to a predetermined direction, In the longitudinal direction Lo of the nonwoven fabric 1, which is a direction coinciding with the longitudinal direction of the nonwoven fabric 1.

The portion of the fiber F2 located on the outer surface 24s located between the through holes 24t of the pattern plate 24 on the upstream side in the carrying direction MD The same can be said about this. That is, the warm air is blown to the portion F2su, whereby the fiber F2 is blown off and moves around. At this time, the fiber F2 also moves into the through hole 24t. Thereafter, warm air is blown to the portion F2tu on the upstream side of the fiber F2 in the transport direction of the fiber F2 in the through hole 24t of the fiber F2, but once the fiber F2 moves into the through hole 24t , The fiber F2 does not return from the inside of the through hole 24t to the outer surface 24s, so that the fiber density of the portion F2su is lowered. On the other hand, the fiber density of the portion F2tu on the upstream side in the transport direction of the fiber F2 in the through hole 24t becomes high. As a result, as in the nonwoven fabric 1 according to the third embodiment, the base 10 comes close to the portion 12TH where the fiber density of the convex portion 12 is high around the convex portion 12, The fiber density is lowered.

The side wall 24w forming the through hole 24t of the pattern plate 24 and the corner portion Co formed at the position where the outer peripheral surface of the suction drum 22 is in contact with the side surface 24w of the air jet nozzle 26 It is difficult for hot air to reach, and the fibers are hard to move from the corner portion (Co). On the other hand, the fibers are blown off by the warm air from the air jet nozzle 26 from the vicinity of the corner Co to move to the corner portion Co. The corner portion Co is a position corresponding to the edge portion 12TE of the convex portion 12 in the nonwoven fabric 1. As a result, the amount of fibers in the corner portion Co is increased in the above-described manufacturing process, and as a result, the edge portion 12TE (12TE) of the convex portion 12, like the nonwoven fabric 1 according to the second embodiment, ) Is higher than that of the central portion 12TC of the convex portion.

The shape of the convex portion 12 is finally determined by the shape of the through hole 24t of the pattern plate 24 and the temperature and wind speed of the warm air blown out from the air jet nozzle 26 and the like.

As shown in Fig. 9, the fibers F3 formed by the sucking and flushing action are subsequently conveyed to the heat-treating unit 28. [ The fiber F3 is heat-treated in the heat treatment device 28, and the shape deformed in the previous stage is fixed. In the heat treatment apparatus 28, the fiber F3 is heat-treated at a relatively low temperature with respect to the melting point of the fiber for a long time with a low-speed warm air, thereby fixing the shape of the fiber F3 formed in the previous process, ) To be flexible. Generally, the temperature and the wind speed of the hot air in the heat treatment unit 28, the time of the heat treatment, and the like depend on the material and the unit weight of the fiber to be used, and it is preferable to determine the optimum temperature and wind speed by experiments or the like.

When the heat treatment of the fibers F3 by the heat treatment device 28 is completed, the nonwoven fabric 1 is completed. The finished nonwoven fabric 1 is cut into a desired size and used.

The method of manufacturing the nonwoven fabric 1 according to the fourth embodiment has been described so far by appropriately changing the shape of the pattern plate 24 and the temperature and wind speed of the hot air blown from the air jet nozzle 26, The nonwoven fabric 1 according to the third embodiment can be produced.

Example

In the present embodiment, the liquid diffusion distance test is performed by the nonwoven fabric having various conditions set. The liquid diffusion distance test is a test for confirming that the liquid absorbed by the nonwoven fabric penetrates with a directivity.

Examples 1 to 3 and comparative examples will now be described.

(Examples 1 to 3)

The nonwoven fabric according to Examples 1 to 3 was produced by the above-mentioned production method. The temperature and wind speed of the hot air blown out from the air jet nozzle 26 at the time of manufacturing these nonwoven fabrics and the temperature and wind speed of the heat treatment in the heat treatment device 28 are shown in Table 1 to be described later. In this nonwoven fabric, the deviation of the fiber density of the convex surface portion of the convex portion was measured by the above-described method of measuring the fiber density around the two measurement points PH and PL shown in Fig. The one measurement point PH is defined by the center point C of the convex surface portion 12T viewed from the plane of the nonwoven fabric 1 and the end edge located on the higher fiber density side along the longitudinal direction Lo from the center point C (12TEE). The other measurement point PL is defined by the center point C of the convex surface portion 12T and the center point C between the center point C and the end edge 12TEE located on the lower fiber density side along the longitudinal direction Lo to be. If the difference in the fiber density measured at these measurement points is large, it can be said that the fiber density of the convex surface portion is biased. Referring to Table 1 to be described later, the fiber density of the convex surface portion of the nonwoven fabric according to Example 2 is more biased than that of Example 1. The fiber density of the convex surface portion of the nonwoven fabric according to Example 3 is more biased than that of Example 2.

(Comparative Example)

The nonwoven fabric according to the comparative example is formed such that the fibers opened by the card unit are not drawn by the suction drum and are not blown by the air jet nozzle and are flattened by the heat treatment unit so that the fiber density becomes uniform. The temperature and the wind speed of the heat treatment in the heat treatment apparatus at this time are shown in Table 1 described later.

Next, the test method of the test performed in the present embodiment will be described. The liquid diffusion distance test was carried out by placing a sample of the nonwoven fabric according to the examples and the comparative example cut in a width of 150 mm and a length of 300 mm on a stainless steel plate having a width of 250 mm and a length of 450 mm, Cc simulated artificial urine was dripped in 2.5 seconds. In this case, the longitudinal direction of the sample is the direction in which the fiber density of the fibers constituting the convex surface portion of the convex portion is biased, the direction in which the fiber density of the convex surface portion is high along the longitudinal direction is DH direction, and the fiber density of the convex surface portion is low And the direction was the DL direction. Then, the distances dh and dl from the dropping position of artificial urine, which artificial urine infiltrated into the DH direction and the DL direction, respectively, were measured. At this time, a value obtained by subtracting the distance dl from the distance dh was defined as a liquid diffusion distance. The liquid diffusion distance test was performed three times, and a value obtained by arithmetically averaging the measured values was calculated as a liquid diffusion distance.

On the other hand, artificial urine used in the liquid diffusion distance test was prepared by dissolving 200 g of urea, 80 g of sodium chloride, 8 g of magnesium sulfate, 3 g of calcium chloride and about 1 g of pigment (blue No. 1) in 10 L of ion- Respectively.

Table 1 shows the results. Table 1 shows the unit weight, the thickness, the preparation conditions, the fiber density of the convex surface portion around each measurement point (PH, PL) and the result of the liquid diffusion distance test of the nonwoven fabrics of Examples 1 to 3 and Comparative Examples. On the other hand, the "thickness" in Table 1 is an average value of the thickness measured three times under a pressure of 3 gf / cm 2, and in the nonwoven fabric according to Examples 1 to 3, the thickness of the convex portion was measured.

As shown in the results of the liquid diffusion distance test in Table 1, the more the fiber density of the convex surface portion is, the larger the liquid diffusion distance is. Therefore, it can be said that the larger the deviation of the fiber density, the more the liquid absorbed by the nonwoven fabric can penetrate in the direction in which the fiber density of the fibers constituting the convex surface portion is biased.

All features as may be understood by one of ordinary skill in the art from the description of the present specification, drawings and claims are not intended to limit the scope of the present invention in any way whatsoever, even if these features are described herein in combination only with respect to certain other features It is to be understood that the present invention can be combined independently and in any combination with other one or more features disclosed herein without departing from the scope of the present invention unless otherwise explicitly stated or unless a technical aspect is not possible or meaningless combination .

For example, in the nonwoven fabric 1 according to another embodiment, the edge portion 12TE of the convex surface portion 12T has a fiber density higher than that of the central portion 12TC of the convex surface portion 12T, The fiber density is lowered as the base 10 approaches the portion 12TH where the fiber density of the convex portion 12 is higher around the convex portion 12 as in the third embodiment.

The present invention is defined as follows.

(1) A nonwoven fabric comprising a base spreading in a planar shape and a plurality of convex portions projecting in the thickness direction from the base,

Each of the convex portions has a convex surface portion,

Each of the convex surface portions is configured so that the fiber density of the convex surface portion deviates in a predetermined direction out of the plane direction of the nonwoven fabric

Non-woven.

(2) In each of the convex portions, the edge portion of the convex surface portion has a higher fiber density than the center portion of the convex surface portion

(1).

(3) The base portion is formed around the convex portion so that the fiber density becomes lower as the convex portion approaches the portion where the fiber density is higher

(1) or (2).

(4) When each of the convex surface portions is bisected by two half convex surface portions so as to have the same area by imaginary lines extending in a direction orthogonal to the predetermined direction as viewed from the plane of the nonwoven fabric, The fiber density of the face portion is higher than that of the other half convex face portion

The nonwoven fabric according to any one of (1) to (3).

(5) The convex portion is disposed along a first direction and a second direction different from the first direction

The nonwoven fabric according to any one of (1) to (4).

(6) The convex portion is formed at equal intervals with the base portion interposed therebetween in the first direction and the second direction

(5).

(7) The method according to any one of

(5) or (6).

(8) The method of producing a nonwoven fabric according to any one of

The nonwoven fabric according to any one of (1) to (7).

1: nonwoven fabric 10: donation
12: convex portion 12T: convex surface portion

Claims (7)

A nonwoven fabric comprising a base portion widened in a planar shape and a plurality of convex portions protruding in the thickness direction from the base portion,
Each of the convex portions has a convex surface portion,
Each convex surface portion is configured such that a fiber density of the convex surface portion is deviated in a predetermined direction out of a plane direction of the nonwoven fabric,
Wherein the base portion has a fiber density lowered around the convex portion as the convex portion approaches a portion having a higher fiber density. The nonwoven fabric according to any one of claims 1 to 5, wherein the edge portion of each convex portion has a fiber density higher than that of the central portion of the convex portion. The nonwoven fabric according to any one of claims 1 to 3, wherein each of the convex portions is divided into two half-convex surface portions by an imaginary line extending in a direction orthogonal to the predetermined direction, Convex surface portion is higher than the fiber density of the other half convex surface portion. The nonwoven fabric according to claim 1 or 2, wherein the convex portion is disposed along a first direction and a second direction different from the first direction. 5. The nonwoven fabric according to claim 4, wherein the convex portion is formed at regular intervals with the base portion interposed therebetween in the first direction and the second direction. The nonwoven fabric according to claim 4, wherein the predetermined direction coincides with the first direction or the second direction. 3. The nonwoven fabric according to claim 1 or 2, wherein the predetermined direction coincides with a conveying direction when the nonwoven fabric is produced.

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