JP3096208B2 - Surface sheet for absorbent articles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a topsheet for absorbent articles, and more particularly, to a topsheet in direct contact with the skin in sanitary napkins and diapers, which maintains its performance and texture. The present invention relates to a three-dimensional surface sheet of an absorbent article that does not allow absorbed body fluids such as blood and urine to flow out during wearing.

[0002]

2. Description of the Related Art Heretofore, perforated films or nonwoven fabrics have been generally used in many cases as surface sheets of absorbent articles such as sanitary napkins and diapers. In the case where a perforated film is used as a surface sheet, Japanese Patent Publication No. Sho 57-17
As disclosed in Japanese Unexamined Patent Publication No. 081,081 and Japanese Unexamined Patent Publication No. Sho 62-68928, a method is used in which an opening is formed on the surface of a plastic film and blood and urine are absorbed through the opening.

[0003]

However, the perforated film has a poor sensation of contact with the skin and gives the user unpleasant sensation. On the other hand, as a nonwoven fabric type surface sheet, there is known a hydrophobic nonwoven fabric in which apertures are formed in an array in order to reduce bodily fluid sensation on the skin of a user and increase the permeability of bodily fluids. Such a nonwoven fabric type surface sheet has a planar structure except for its opening, and a considerable part of the surface is in contact with the skin. For this reason, it is desirable to further reduce the contact with the skin and improve the air permeability between the skin and the topsheet.

If the ribs provided so as to surround the opening are not sufficiently hard, the ribs are crushed when body pressure is applied to the topsheet or when the absorber that has absorbed body fluids expands, and the topsheet and the topsheet may be damaged. The gap with the absorber becomes small, and the body fluid may ooze out of the absorber through the opening to the outer surface of the topsheet, and the initial function may not be sufficiently exhibited. Therefore, the purpose of the present invention is to maintain its performance and texture,
An object of the present invention is to provide a surface sheet of an absorbent article that can reduce the feeling of wetness by a body fluid, improve the feel of the skin, and prevent the body fluid from leaking from the absorber through the opening to the outer surface of the topsheet.

[0005]

SUMMARY OF THE INVENTION The present invention comprises a nonwoven fabric sheet formed by fusing thermoplastic synthetic fibers; the nonwoven fabric sheet has multiple rows of ridges and grooves so as not to have a flat portion. The ridges are convexly curved, and the grooves are concavely curved; the grooves are ribbed apertures extending from the front surface to the back surface of the nonwoven sheet. The above-mentioned object has been attained by providing a surface sheet of an absorbent article, wherein the rib is formed to be harder than portions other than the rib.

[0006]

Since the topsheet of the present invention is made of a nonwoven fabric, when used as a topsheet on the skin contact side of an absorbent article, the cloth-like feel is obtained and the sheet surface does not have a flat portion. Since a large number of ridges and grooves are alternately arranged, the contact area with the skin is significantly reduced, the adhesion between the topsheet and the skin is reduced, and the feeling of body fluid wetting is reduced. Further, the ribs extending from the front surface to the back surface of the nonwoven fabric sheet in the groove are formed harder than the nonwoven fabric (nonwoven fabric of the ridge portion) other than the ribs. Even if the absorber absorbs the body fluid or expands, and the absorber is pressed against the topsheet, the body fluid absorbed by the absorber is maintained to maintain a large distance between the absorber and the topsheet. Has the effect of not returning to the topsheet.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a surface sheet of an absorbent article according to the present invention will be described below in detail with reference to the accompanying drawings. FIG.
FIG. 1 is a perspective view of an absorbent article using a topsheet of the absorbent article of the present embodiment, which is cut away in cross section. FIG. 2 is a partial cross-sectional view of the topsheet of the absorbent article according to the present embodiment.
FIG. 3 is an enlarged perspective view illustrating a main part of the topsheet of the absorbent article according to the present embodiment.

As shown in FIG. 1, a topsheet 2 of an absorbent article according to this embodiment is used for a sanitary napkin 1 which is an absorbent article. As shown in FIGS. 2 and 3, the topsheet 2 is made of a nonwoven fabric sheet 2 formed by fusing thermoplastic synthetic fibers, and the surface 2A of the topsheet 2 is multi-rowed so as not to have a flat portion. Ridges 12, 12, ... and grooves 13, 1
Are alternately arranged. The ridge portion 12 is curved in a convex shape, and the groove portion 13 is curved in a concave shape. Groove 13
Has an opening 15 with a rib 14 extending from the front surface to the back surface of the nonwoven fabric sheet, and the rib 14 is formed to be harder than portions other than the rib 14.

The surface sheet 2 of the absorbent article of this embodiment will be further described. As shown in FIG. 1, the surface sheet 2 is used for a sanitary napkin 1. The sanitary napkin 1 is made of a topsheet 2, a water-impermeable leakproof material. 3, an intermediate layer 4 having cushioning properties and an absorber 5. The absorber 5 is covered with the leakproof material 3 except for the skin contact side, and the skin contact side of the absorber 5 is covered with the surface sheet 2 via the intermediate layer 4. The topsheet 2 encloses the entire absorbent body 5, and the portion of the topsheet 2 with the intermediate layer 4 interposed therebetween is the body fluid absorbing portion of the sanitary napkin 1 and serves as a skin contact surface.

[0010] The topsheet 2 is made of a nonwoven sheet which is preferable for contact with the skin, and the nonwoven sheet is formed by fusing thermoplastic synthetic fibers. The fusion method is not particularly limited, and the fibers can be fused to each other by, for example, a heated embossing roll or hot air. The nonwoven fabric sheet is formed by fusing known thermoplastic synthetic fibers such as polyethylene terephthalate, polyethylene, and polypropylene. These thermoplastic synthetic fibers may be core-sheath type or side-by-side type composite fibers. The thermoplastic synthetic fibers may be used alone or in combination of two or more. Although the fiber diameter of the thermoplastic synthetic fiber is not particularly limited, it is 0.1 to 6.0.
A denier range is preferred. If the fiber diameter exceeds this, the concealing property of the nonwoven fabric is deteriorated, and the body fluid absorbed by the absorber may be seen through. If the fiber diameter is less than this, the distance between the fibers becomes small, and the liquid remains due to capillary force. As the nonwoven sheet used suction <br/> heating preparative bonded nonwoven fabric produced thermoplastic synthetic fibers by spreading Ri by the carding machine, spunbonded nonwoven fabric produced by melt spinning, or melt blown non-woven fabric be able to. The topsheet of the present invention can be composed of a single nonwoven fabric sheet, but various unopened sheets obtained by combining nonwoven fabrics, nonwoven fabrics / films or nonwoven fabrics with other materials can also be used. The original thickness and basis weight (basis weight) of the nonwoven fabric sheet before opening are not particularly limited, but the thickness is preferably in the range of 0.2 to 2 mm in terms of texture and workability, and the basis weight is 15 to 45 g. / M ² is preferable in terms of texture, uneven formation, and workability. still,
The non-perforated nonwoven fabric sheet of this embodiment is a concentric PET / PE
Composite fiber (volume ratio (40/60), about 2 denier) -7
0 wt%, PET (about 6 denier) -30 wt% suction heat bond nonwoven fabric (approximate thickness of about 0.6
mm, basis weight 20 g / m ² ).

As shown in FIG. 2, the surface 2A of the topsheet 2
On the (skin contact surface), a convexly curved ridge portion 12 and a concavely curved groove portion 13 are formed between the ridge portions 12. The ridge portions 12 of the topsheet 2 are formed in multiple rows so as not to have a flat portion. Also, the groove 13 is the ridge 1
There is a multi-row between the ridges 12 and the ridges 12, and the ridges 12 are formed of a continuous surface. Further, the groove 13 is also formed so as not to have a flat portion. Pitch between ridges 12 (pitch between rows of adjacent ridges 12, 12) and pitch between grooves 13 (pitch between rows of adjacent grooves 13, 13)
Are each 0.5 to 20 mm, especially 1.5 to 4.0 m
m is desirable. When the pitch is more than 20mm, ridge is widened, the sheet is then flattened and rather than be crushed ribs when the pressure is applied, the pitch is too narrow ridge that it is less than 0.5mm, ridges Ya Inability to form tightly around the aperture. In the sanitary napkin using the topsheet 2 configured as described above, only a part of the ridge portion 12 directly contacts the skin when the sanitary napkin is attached. In this embodiment, the pitches P between the rows of the ridges and between the rows of the grooves are each P = 2.
mm (FIG. 2).

The groove 13 has an opening 15 with a rib 14 extending from the front surface 2A of the top sheet 2 to the back surface 2B. The depth S of the apertures 15 is 1.1 to 3.0 times the thickness of the non-perforated nonwoven sheet, particularly 1.2 to 2.5 times.
And it is absorbent or intermediate layer fold is, the distance between the ridges of the surface sheet <br/> large holding, the body fluid absorbed in the absorbent desirable in that it does not return to the napkin surface. Opening 1
5 has a diameter D of 0.2 to 10 mm, especially 0.5 to 1.5 m.
m is desirable from the viewpoint that body fluids such as blood can pass through without pooling. If the diameter D is less than 0.2 mm, the size of the holes becomes close to the inter-fiber distance of the nonwoven fabric, and it becomes substantially meaningless to form the holes. Diameter D is 1
If it exceeds 0 mm, the aperture is too large and the skin may directly contact the absorber, which is not preferable. The pitch between the adjacent openings 14 with ribs 14 in each groove (the pitch between the openings 15 with ribs 14 in the machine direction of the topsheet) is
0.4 to 40 mm, particularly 1.5 to 8 mm is desirable. If the pitch exceeds 40 mm, the existence of the openings becomes coarse, and the liquid permeability decreases. If the pitch is less than 0.4 mm, the perimeter of the opening becomes small, and the periphery of the opening cannot be firmly formed. However, this pitch can be made smaller than the pitch between the ridges because there is no ridge. In the topsheet 2 in which the openings 15 with the ribs 14 are formed, the permeability of body fluids such as blood is good and there is no liquid pool. Also, no return of blood or the like once absorbed on the back surface side of the topsheet 2 is observed. In this embodiment, the opening diameter D is D
= 1 mm, the depth S of the apertures 15 is 2.0 times the thickness of the non-perforated nonwoven sheet (Fig. 2).

The ribs 14 will be described in detail. The ribs 14 are formed on the inner wall surface of the opening 15, and the strength of the opening 15 is enhanced by the ribs 14. Therefore, the term “rib 14” in the present invention means that the nonwoven fabric has a significant difference S (S> 0.1 × unopened sheet thickness) at the periphery of the opening toward the back surface at least around the opening in FIG. Refers to the projecting part.

That is, as shown in FIG. 3, the ribs 14 of the topsheet 2 made of the above nonwoven fabric sheet have relatively dense thermoplastic synthetic fibers.
No. 2 non-woven fabric). That is,
The ridges 12 that are in direct contact with the convex skin maintain the soft texture unique to the nonwoven fabric as much as possible, and only the ribs 14 are formed harder than the portions other than the ribs 14 so that the openings 15 are not crushed by body pressure or the like.

The topsheet (perforated sheet) 2 of the present invention having the above-described structure preferably has an apparent thickness from the upper end of the ridge portion to the lower end of the rib of 1.2 to 2.0 in comparison with an unperforated sheet.
It is 5.0 times, the thickness at the time of compression of the pressure 50g f / cm ² G and preferably 1.1 to 4.0 times. The topsheet 2 and the non-perforated nonwoven fabric sheet of the present example were combined with a Tensilon measuring machine manufactured by Orientec Co., Ltd. and C
Measure the sheet properties (machine direction (MD) and transverse direction (CD)) using OMPRESSION TESTER,
The results are shown in Table 1. In Table 1, the tensile strength is JIS L1096.
6.1 2 according to, the apparent thickness JIS L1096
6 . 5 was measured. The thickness at the time of compression of the pressure 50g f / cm ² G was determined by compression testing method using the KES-FB3 compression tester. And a pressure of 50 gf / cm ²
The compression energy at the time of compression of G is the initial state (pressure =
0) to a pressure of 50g f / cm ² G is applied refers to the integral value of the moving distance × pressure load cell when compressed,
The value automatically calculated from the compression tester was read.

[0016]

[Table 1]

Next, a method for producing the topsheet 2 of the absorbent article will be described in detail. The topsheet 2 can be obtained by manufacturing the nonwoven fabric sheet by the above-described known manufacturing technique by entanglement of fibers and mechanically opening the nonwoven fabric sheet. For example, a first pressing die having a large number of pyramidal or conical convex pins arranged in a row and the rows being arranged in multiple rows, and a projection fitted between the multiple rows of convex pins. It can be obtained by inserting a non-perforated nonwoven fabric sheet between the non-perforated nonwoven fabric sheet and the second pressing die having a strip portion.

More specifically, Japanese Patent Application No. 5-116 of the present applicant is disclosed.
The method described in No. 104 can be used. As shown in FIG. 4 and FIG. 5, a number of pyramidal or conical convex pins 22, 22.
And a plurality of rows of pin rolls 21 (first pressing dies), and the ridges 24, 24 fitted between the multi-row convex pins. Ridge roll 23
A large number of holes can be formed by interposing the non-perforated nonwoven fabric sheet 20 with the (second pressing mold).

In this opening method, the pin roll 21 is
The convex pins 22 are arranged in rows along the direction of transport of the non-perforated nonwoven fabric sheet 20, and the rows are arranged in multiple rows. On the other hand, as shown in FIG. 5, the ridge rolls 23 of the ridge rolls 23 are fitted between the rows of the pins 22 of the pin roll 21. For this reason, the ridges 12 of the topsheet 2 are easily formed by the ridges 24 of the ridge rolls 23, and the grooves 13 and the apertures 15 are formed by pressing the convex pins 22 of the pin roll 21 against the nonwoven fabric sheet 20. , And a rib 14 are formed. In this case, the pin roll 21 is
When heated to 60 ° C. and used, the nonwoven fabric (nonwoven fabric forming the ribs) in contact with the periphery of the convex pin 22 is partially softened or partially melted by heat, and the surface after being pulled out from the convex pin 22 Only the nonwoven fabric forming the ribs 14 of the sheet 2 can be formed to be harder than portions other than the ribs. In the formation of the topsheet 2 of this example, the nonwoven fabric sheet 20 was opened with the pin roll temperature set at 115 ° C.

When the topsheet 2 produced as described above is used for the sanitary napkin 1, the sanitary napkin 1
Had excellent performance in texture, liquid permeability, liquid return prevention and cushioning. From these results, when the topsheet 2 of the present invention is used for the sanitary napkin 1, firstly,
The portion of the topsheet 2 that comes into contact with the skin is small, and the portion that comes into contact with the skin retains the feel of a conventional soft non-woven fabric, so that the feeling of wearing is good and the feeling of wetness thereafter can be reduced. Second, since the topsheet 2 is three-dimensional, blood can be absorbed into the absorber 5 through the opening 15 immediately without including a flat portion or a blood pool. Third, since the ribs 14 are formed to be harder than portions other than the ribs, even if a body pressure is applied to the topsheet, the sheet thickness is not reduced and the cushioning property is good. For this reason, a certain distance is maintained between the topsheet 2 and the absorber 5 or the intermediate layer 4, and the body fluid such as blood once absorbed hardly returns from the absorber 5 to the surface 2 </ b> A of the topsheet 2. be able to. In this embodiment, the topsheet 2 is used for the sanitary napkin 1. However, the topsheet is not limited to this use, and may be used for other absorbent articles such as disposable diapers. it can.

[0021]

As described above, the surface sheet of the absorbent article according to the present invention improves the feel by reducing the feeling of wetting by body fluid while maintaining its performance and texture, and the body sheet passes through the opening from the absorber and passes through the surface sheet. Is prevented from seeping out to the outer surface.

[Brief description of the drawings]

FIG. 1 is a perspective view of an absorbent article using a topsheet of the absorbent article of the present embodiment, the cross section being cut away.

FIG. 2 is a partial cross-sectional view of a topsheet of the absorbent article according to the present embodiment.

FIG. 3 is an enlarged perspective view illustrating a main part of a fiber of a topsheet of the absorbent article according to the present embodiment.

FIG. 4 is an explanatory diagram of a manufacturing apparatus for manufacturing a topsheet of an absorbent article of the present embodiment.

FIG. 5 is a partial cross-sectional view showing a process in which a nonwoven fabric sheet is opened as viewed from a sheet flow direction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sanitary napkin 2 Surface sheet 2A Surface 2B Back surface 3 Leakproof material 4 Intermediate layer 5 Absorber 12 Ridge 13 Groove 14 Rib 15 Opening 20 Nonwoven fabric sheet 21 Pin roll 22 Convex pin 23 Ridge 24 24 Ridge

Continuation of front page (56) References JP-A-3-260153 (JP, A) JP-A-58-132155 (JP, A) JP-A-52-34069 (JP, A) JP-A-3-297464 (JP) , A) (58) Fields studied (Int. Cl. ⁷ , DB name) D04H 1/00-17/00 A61F 13/15

Claims (5)

(57) [Claims] 1. A non-woven fabric sheet formed by fusing thermoplastic synthetic fibers; a multi-row ridge portion and a groove portion are alternately arranged in the non-woven fabric sheet so as not to have a flat portion; The ridges are convexly curved, and the grooves are concavely curved; the grooves have ribbed apertures extending from the front surface to the back surface of the nonwoven sheet; The top sheet of the absorbent article, wherein the rib is formed harder than a portion other than the rib. 2. The pitch between adjacent rows of ridges and the pitch between adjacent rows of grooves are each 0.5.
The surface sheet according to claim 1, which has a thickness of from 20 mm to 20 mm. 3. The surface sheet according to claim 1, wherein the opening diameter is 0.2 mm to 10 mm. 4. The topsheet according to claim 1, wherein a pitch between adjacent openings in the groove is 0.5 to 40 mm. 5. The topsheet according to claim 1, wherein the depth of the perforations is 1.1 to 3.0 times the thickness of the non-perforated nonwoven fabric sheet.