JPH04187146A - Surface sheet for absorptive product - Google Patents

Abstract

PURPOSE:To decrease adhesion of a surface sheet to skin and to decrease wet feeling with humor by constituting the surface sheet having a number of liq. conducting holes perforating the upper and lower faces of a non-woven fabric prepd. by fusing a thermoplastic synthetic fiber, and forming a lot of discontinuous projections projecting from the upper face in the upper direction with a part of the non-woven fabric. CONSTITUTION:A surface sheet 4 has an upper face 11, a lower face 12, a number of liq. conducting holes 13 perforating the upper and lower faces and a lot of discontinuous projections 14 formed in such a way that a part of the surface sheet is projected upward of the upper face 11. The surface sheet is used in such a way that the projections are brought into contact with skin and is prepd. of a non-woven fabric prepd. by fusing a thermoplastic synthetic fiber 15. The projection 14 has an outer diameter D of 1-5mm and a height H of 1-5mm at a rising part from the surface sheet and the top part of the projection 14 has a convex face with a proper curvature as shown in the figure or a flat face. The liq. conducting hole 13 has a diameter d1 of 0.2-5 mm at the upper face 11 pref. <0.7-3.5mm and is perforated with a proper taper from the upper face 11 to the lower face 12. The taper has a case wherein not only d1>d2 but d1<=d2 can be included as shown in the figure.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a topsheet for covering an absorbent core to constitute body fluid absorbent articles such as sanitary napkins, sanitary tampons, and disposable diapers.

(Prior art and problems to be solved by the invention) Conventionally, this type of surface sheet has been designed to reduce the feeling of body fluid wetness on the skin when worn, and to relatively increase the permeability of body fluids. A nonwoven fabric in which liquid guide holes are arranged in a given pattern is known. However, this top sheet has a planar structure and may come into close contact with the wearer's skin. Since this sheet is a nonwoven fabric, it has the effect of reducing its adhesion, but it is desirable to further reduce its adhesion and improve the air permeability between the sheet and the skin.

On the other hand, in order to further reduce the feeling of body fluid wetness on the top sheet, a given pattern of liquid guide holes is formed on the plastic film, and a guide hole is formed in which the liquid guide holes extend downward from the periphery of the plastic film. What forms the liquid tube is
For example, it is known from Japanese Patent Publication No. 57-17081. This top sheet can achieve the purpose of reducing the contact area with the wearer's skin and the feeling of body fluid wetness on the skin (and also relatively high body fluid permeability).

However, since this top sheet is a plastic film, it is inevitable that it will have a slimy feel to the touch. Moreover, this texture is generally disliked by wearers, and there is still a problem in that this sheet also tends to adhere closely to the skin, making it difficult to obtain sufficient air permeability between the sheet and the skin.

Therefore, the present invention solves the problems of the above-mentioned prior art by constructing the topsheet from a nonwoven fabric made of heat-fused fibers and forming a large number of discontinuous protrusions projecting upward from the top surface of the topsheet. It aims to solve the problem.

(Means for Solving the Problems) In order to solve the above problems, the gist of the configuration of the present invention is as follows.

The present invention is directed to surface sheets of absorbent articles for treating body fluids such as sanitary napkins and disposable diapers.

In this invention, the top sheet has an upper surface, a lower surface, and a large number of liquid introduction holes penetrating the upper and lower surfaces. The topsheet is made of a nonwoven fabric made by fusing thermoplastic synthetic fibers, and a large number of discontinuous protrusions projecting upward from the top surface are formed on the topsheet by a portion of the nonwoven fabric.

In one of the preferred embodiments of the present invention, at least some of the liquid guide holes form liquid guide pipes extending downward from the lower surface.

(Function) In the top sheet according to the present invention configured as described above, the top sheet is made of a non-woven fabric, which provides a unique texture, and the many discontinuous protrusions that protrude upward from the top surface of the sheet provide a comfortable texture. The area of contact with the wearer's skin is significantly reduced, the close contact of the top sheet to the skin is reduced, and the feeling of wetness with body fluids can be reduced (corresponding to claim 1).

In addition to the above, the liquid guide hole is in the form of a liquid guide tube, which allows body fluid to quickly permeate from the surface sheet to the absorbent core;
By preventing the backflow, it is possible to further reduce the feeling of body fluid wetness on the upper surface of the topsheet (corresponding to claim 2).

(Example) An example of the top sheet according to the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cutaway perspective view of a sanitary napkin 2 as an example of using the top sheet according to the present invention. The napkin 2 is composed of a top sheet 4 according to the present invention in which liquid guide holes 13 (to be described later) are formed, a liquid-impermeable back sheet 5, and an absorbent core 6' interposed between these sheets.

2 and 3 are an enlarged perspective view of the top sheet 4 and a sectional view taken along line 3-3 in FIG. 2. The top sheet 4 has an upper surface 11. It has a lower surface 12, a large number of liquid guide holes 13 penetrating the upper and lower surfaces 11, 12, and a large number of discontinuous protrusions 14 formed so that a portion of the top sheet protrudes above the upper surface 11. The top sheet 4 is used with the projections 4 in contact with the skin, and is made of a nonwoven fabric to which thermoplastic synthetic fibers 15 are fused. The thermoplastic synthetic fiber 15 is made of olefin, polyester, polyamide, or other thermoplastic synthetic resin. Fiber 15 has a fineness of 0.01~
ld (denier), and the nonwoven fabric made of 15 fibers has a basis weight of 10 to 50 g/m'1, especially 20 to 40 g.
/m', and the density is 0.03~0, 5 g/c
It is preferable to set it to rn3 in order to obtain a good texture and practical strength.

This nonwoven fabric may be breathable or impermeable, and the present invention can be practiced in either case.

As shown in FIG. 3, the protrusion 14 has an outer diameter of 1 to 5 mm and a height H of 1 to 5 mm at the rising portion from the top sheet 4.
5 mm, and the top of the protrusion 14 can be made into a convex surface with an appropriate curvature as shown in the figure, or it can be made flat (not shown). Although the present invention does not specify the shape of the protrusion 15, From a practical point of view, it is generally preferable to have a chevron shape, a truncated cone shape, a cylindrical shape, etc. The value of the outer diameter is determined in this sense.The area occupied by the projections 14 on the top sheet 4 The ratio is 1 to 70%, especially the number of protrusions 14 and the outer diameter 1 to make it 3 to 60%.
Choose 4.

The liquid guide hole 13 has a diameter d1 of 0.2 to 5 on the upper surface 11.
mm.

Among other things, the total open pore area ratio is 5 to 70%, especially 10 to 50%.

=6- The liquid guide hole 13 penetrates from the upper surface 11 to the lower surface 12 with an appropriate taper. Such an appropriate taper includes not only the case where dl>d2 as shown in the figure but also the case where d1≦d2. Further, the presence of the liquid guide hole 13 is not limited to the illustrated example, and may be present in the protrusion 14.

FIG. 4 shows that in the top sheet 4, the liquid guide holes 13 are located on the lower surface 1.
FIG. 3 is a sectional view similar to FIG. 3, showing an example in which a liquid guiding pipe 16 is formed extending downward from 2, and its tip has a diameter d2.

The liquid guide pipe 16 is formed from a part of a surface sheet made of nonwoven fabric, and has an opening size of d, ≧d2, and a length L of 1 to 5.
The conditions are the same as in FIG. 3 except that mm is used. Such a topsheet 4 is used in the napkin 2 shown in the first diagram with the tip of the liquid guide tube 16 facing the absorbent core 6 side.

A suitable material for obtaining the above-mentioned topsheet 4 is a melt-blown nonwoven fabric. Although illustration of the manufacturing process for the topsheet 4 is omitted, an example of using the melt-blown nonwoven fabric will be described as follows. First, a molten polymer is discharged from a melt blowing device, and it is made into ultra-fine fibers using a high-speed, high-temperature air stream. It is deposited on the top surface of a conveyor with forming elements to form a non-woven fabric. At the same time, a suction placed on the underside of the conveyor applies negative pressure to a given area of the nonwoven fabric where the fibers are still in a softened state, and the nonwoven fabric is suction-stretched and blended into each forming element of the conveyor in the area where this negative pressure is applied. By that,
For example, the protrusion 14 can be made from a piece of non-woven fabric.

Further, the liquid guide holes 13 can be provided by a method of press-contacting a heating needle to a nonwoven fabric, a method of punching using a punching die, or the like. At this time, if a recess is formed in the nonwoven fabric using the molding element and the liquid introduction hole 13 is provided in the recess, the periphery of the hole can be finished neatly. The liquid guide hole 13 with the liquid guide pipe 16 can be obtained by suctioning and hanging the nonwoven fabric into a tubular molded element corresponding to the liquid guide pipe 16, and by tearing off the tip thereof. The drooping tip can be melted and broken by contacting it with a heated roll, for example. When the nonwoven fabric is drawn by suction to form the liquid conduit 16, the fibers 15 of the nonwoven fabric tend to be oriented in the length direction along the wall of the liquid conduit 16, which is effective for permeating body fluids by capillary action. It is. The process of providing the protrusions 14 and liquid guide holes 13 is performed by first forming a nonwoven fabric as necessary, and treating it with a heating roll (including an embossing roll) or ultrasonic waves to smooth the surface, and This can also be done after increasing the fusion rate and strength. Needless to say, appropriate auxiliary means can be used to provide the protrusion 14, the liquid guide hole 13, the liquid guide pipe 16, etc.

Moreover, it is acceptable even if one surface sheet 4 includes a mixture of liquid guide holes 13 having liquid guide pipes 16 and those not having liquid guide holes 13. The protrusions 14 can also be obtained by hot embossing, but in that case the protrusions 14 tend to be hard, so this is generally not a preferred processing method.

Returning to FIG. 1, the topsheet 4 and backsheet 5 as described above have an absorbent core 6 interposed between them,
By tightly joining the four circumferences, sanitary napkin 2
It can be done. Usually, the back sheet 5 is a polyethylene or other thermoplastic synthetic resin sheet, and the absorbent core 6 is a press-molded mixture of pulverized pulp, thermoplastic synthetic fibers, and superabsorbent polymer powder.

(Effect) When the top sheet configured as described above is used in absorbent articles such as sanitary napkins and disposable diapers, the top sheet has a large number of discontinuous protrusions, so it adheres closely to the wearer's skin. hard. Furthermore, due to the synergistic effect of the non-woven fabric surface sheet and the efficient permeation of body fluids into the absorbent core due to the large number of liquid guide holes, there is less adhesion and good breathability (bodily fluid wet feeling). It is possible to obtain an absorbent article with extremely low

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of a sanitary napkin shown as an example suitable for using the top sheet according to the present invention;
FIG. 2 is an enlarged perspective view showing a part of the top sheet according to the present invention, FIG. 3 is a sectional view taken along the line 3-3 in FIG. 2, and FIG. - a sectional view similar to that shown in FIG. 3; 4...Top sheet 11...Top surface 12...Bottom surface 13...Liquid guide hole 14...Protrusion 15...Fiber 16...Liquid guide pipe

Claims (1)

[Claims] (l) A top sheet of an absorbent article having an upper surface, a lower surface, and a large number of liquid introduction holes penetrating the upper and lower surfaces, the top sheet being a nonwoven fabric made by fusing thermoplastic synthetic fibers. The topsheet is characterized in that a number of discontinuous projections projecting upward from the top surface are formed at given intervals by a portion of the nonwoven fabric. (2) The surface sheet according to claim 1, wherein at least some of the liquid guide holes form liquid guide pipes extending downward from the lower surface.