JPH03106364A - Compound sheet for surface material of absorptive product - Google Patents

Abstract

PURPOSE:To prevent a stain after use from being easily seen with a wet feeling of a film surface, brought into contact with the skin, eliminated and with a return amount of liquid decreased, by allowing liquid to flow in an absorptive core material through fine holes and promoting a movement of the liquid to the absorptive core material, in an unwoven fabric adhesively attached to a film. CONSTITUTION:A thermo-adhesive film 1, made non-transparent, and an unwoven fabric 2 of small thermo-adhesion are thermo-adhesively attached with many fine holes 3 perforated in a surface of the film 1. At the time of drilling these fine holes 3, fine pieces 5, extruded from a fine hole parts, are sunk from the surface of the film 1 and thermo-adhesively attached to the unwoven fabric 2. An annular clearance 6 is formed between an internal peripheral edge of the fine hole 3 and a peripheral edge of the fine piece 5. Accordingly, when this compound sheet 7 is used as a surface material of an absorptive product such as a physiological napkin and a throwaway diaper or the like, stain liquid, discharged from a surface side of the film 1, passes through the annular clearance 6 from the many fine holes 3, and the stain liquid is allowed to smoothly flow in an absorptive core material via the unwoven fabric 2 and absorbed. Residual liquid on the film surface is almost eliminated, while also return liquid to the film side is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention' relates to a composite sheet that is applied as a surface material for absorbent products such as sanitary napkins and diapers.

(Prior art) As is well known, absorbent products such as sanitary napkins and diapers are
It has a water-absorbing core material such as wood pulp, rayon, or cotton, with a waterproof material on the back side and a surface material called a top sheet on the front side that comes into contact with the skin.

The surface materials of recent absorbent products include non-woven fabric sheets and plastic films with numerous pores, which eliminate liquid residue on the surface material and liquid return from the absorbent core material when worn. In addition, various improvements have been made to improve the cleanliness of the appearance after use. For example, JP-A-63
The facing described in the 29640 publication is formed of an opacified plastic film sheet with holes drilled by a number of pins. When this plastic film surface material is used for absorbent products,
The surface of the absorbent product can be covered opaquely, and since a flap or pad remains around the hole when punctured with a pin, the liquid absorbed into the absorbent core is prevented from flowing back. It is said that it is difficult to see the liquid inside the absorbent core material. Due to these advantages, this type of surface material has become widely used, especially in sanitary napkins.

(Problem to be Solved by the Invention) However, when an absorbent core material is covered with the above-mentioned conventional surface material made of perforated film, it is difficult to bring the surface material and the absorbent core into close contact over the entire surface. A gap is partially formed between the absorbent core material and the absorbent core material, and the permeability of liquid to the absorbent core material is reduced in this gap portion. This disadvantage can be improved to some extent by coating the surface material with a hydrophilic substance, but
If a hydrophilic substance is applied, the dry feeling during use will be impaired. In addition, the flaps or flaps created during the above-mentioned drilling also have the effect of making it difficult to see dirt on the absorbent core material after use, but since each hole in the surface material is a through hole without a bottom, the surface material becomes opaque. Even if it is removed, the dirt will appear as spots.

The purpose of the present invention is to create a surface for absorbent products that has a small amount of liquid returning, has excellent liquid introduction properties to the absorbent core side, and has excellent dryness on the surface, and also makes it difficult to see dirt on the absorbent core material after use. Our objective is to provide composite sheets that can be used as materials.

(Means for Solving the Problems) In order to achieve the above object, a composite sheet according to the present invention comprises a heat-adhesive film made opaque and having a large number of pores perforated on its entire surface, and a thin heat-adhesive nonwoven film. are thermally bonded to the nonwoven fabric, and the strip extruded from the pore when the pore is bored sinks from the film surface at approximately the center of the pore and is thermally bonded to the nonwoven fabric. An annular gap through which the nonwoven fabric is exposed is formed between the inner circumferential edge of the hole and the outer circumferential edge of the strip.

Various types of resin films containing calcium carbonate or titanium oxide can be used as the opaque heat-adhesive film, but polyethylene containing calcium carbonate and having a relatively low melting point is preferable, and its thickness is 30 to 30 mm. 40
μm is appropriate.

In addition, the heat-adhesive nonwoven fabric is preferably one in which at least a portion of the surface is made of synthetic fibers of the same quality as the above-mentioned film;
When the film is made of polyethylene, a thin nonwoven fabric having a weight of 25 to 40 g/m2 obtained by thermally processing a composite fiber web whose sheath component is polyethylene and whose core component is polykpropylene or polyester is suitable.

Methods for forming a large number of pores in a composite sheet made of the film and nonwoven fabric described above include truncated conical, truncated pyramid,
Alternatively, the composite sheet is passed between a pair of rollers consisting of a perforated roller and a smooth roller, each of which has a large number of small protrusions on its circumferential surface having a cylindrical or prismatic top surface, and embossing is performed from the film side. It is preferable to make the small protrusions of the perforation roller penetrate through the film.In this case, if the perforation roller is heated to a temperature around the melting point of the film, the small pieces pushed out to the top surface of the small protrusions during perforation will become part of the film. The film is bonded to the nonwoven fabric in a depressed state, and an annular gap is formed between the inner circumferential edge of each pore drilled in the film surface and the outer circumferential edge of each strip depressed and bonded to the nonwoven fabric. It can be made with a hole structure.

The opening size of one pore drilled in the film surface is 1 to 3-, the opening ratio is 30 to 60%, and the depression depth of the strip is 0.
．． 6 to 1.2 mm, and the ratio of the opening size of the pore to the size of the strip is 1. :0.4 to 1:1, and when the diameter of the pore is about 1.6 cm, the diameter of the strip is about 1 cm, and the depth of depression is about 1 am, the inner peripheral edge of the pore and The area of the gap between the strip and the outer peripheral edge is calculated to be approximately 2.5 mnl, but in reality it is slightly smaller than this.

(Function) The porous film that forms the surface layer of the composite sheet allows liquid to flow to the absorbent core material through its pores, and the nonwoven fabric adhered to the film promotes the movement of liquid to the absorbent core material. , eliminates liquid residue on the film surface and eliminates the feeling of wetness on the film surface that comes into contact with the skin during use.Furthermore, the sunken strips prevent dirt on the absorbent core material from being directly visible through the pores. Eliminates the feeling of uncleanness after use and prevents backflow of liquid.

(Example) Below, drawings showing examples of the present invention will be described. Figures 1 and 2 are a cross-sectional view and a plan view through the pores of the composite sheet, in which (1) shows the thickness of the opaque 5 6 membrane and (1) the thickness in which lucium carbonate is blended. 35μ
m medium density polyethylene film [manufactured by Tokuyama Soda Co., Ltd., Bolam 35 (density 0.9 g/cpo) (melting point 125
℃)] was used, and the thermoadhesive nonwoven fabric (2) was a composite fiber whose sheath component was high-density polyethylene and whose core component was polyester [Daiwabo Co., Ltd., NBF (SH) 3DX 5
A thin non-woven fabric with a hydrophilic property treatment of about 30 g/m'' is used, in which the fibers are bonded by melting the sheath component by hot-air processing of a card web of 1 mm. The adhesive film ( ) and the heat-adhesive nonwoven fabric (2) are thermally bonded, and the film (1)
A large number of pores (3) having a diameter of 1.8+n+n are drilled in a regularly distributed manner on the surface, and the aperture ratio occupied by the large number of pores (3) is approximately 40%. Also, each pore (3)
A depression (4) is formed in the heat-adhesive nonwoven fabric (2) at the part indicated by , and a depression (4) is formed in the surface of the film (1), and the bottom surface of the depression (4) contains the small pieces extruded from the pore during perforation. (5)
is glued to the outer edge of the strip (5) and the pore (3).
) has a structure in which the film (1) is broken and an annular gap (6) is formed to allow liquid to enter the nonwoven fabric (2) from the surface of the film (1). There is.

The surface-perforated composite sheet (7) having the above-mentioned structure has perforations with a large number of truncated cone-shaped small protrusions (10) (10) on the outer peripheral surface, as schematically illustrated in FIGS. 3 and 4, for example. Using a device in which a roller (11) and a roller (12) with a smooth surface are arranged one above the other with a slight gap (to the extent that they do not contact each other), the perforating roller (11) is heated at 130 to 135°C with a smooth surface. The heat-adhesive film and the heat-adhesive nonwoven fabric (2) are stacked vertically from one side of the device, and the rollers (12) are heated to 90 to 95°C, and the two rollers are rotated in the direction of the arrow. It can be obtained by passing it between rollers (11) and (12). That is, the heated roller (1
1) When the heat-adhesive film (1) and the heat-adhesive non-woven fabric (2) are supplied between (12) without overlapping, the film (1) is softened by the heat of the perforation roller (11),
The protrusion (10) of the perforation roller (11) penetrates and perforates the softened film (1) as if cutting it by melting, and
The top surface (i0A) of each small protrusion (10) pushes the circular strip (5) away from the perforation into the nonwoven fabric (2) and presses it toward the lower surface of the nonwoven fabric (2). piece (5)
It can be manufactured by thermally adhering it to a nonwoven fabric (2).

Of course, instead of the punching roller (11) and the smooth roller (12), a punching method can also be used in which a heated punching plate provided with a large number of small protrusions is moved up and down onto the table.

When the thermoplastic heat-adhesive film (1) is perforated using the heated perforation roller (11) or perforation plate as described above, the inner periphery of the perforation part is Place the film (1) in contact with the side of the small protrusion (10).
) softens or melts, and as shown in FIG. Piece (5)
In some cases, it may remain connected to the outer periphery of the However, this filamentous body (8) is so small that it does not significantly affect the annular gap described above.

When the composite sheet of the present invention is used as a surface material for a sanitary napkin, the shape of the strip (5) described above is such that it bulges toward the pores (3) as shown in FIG. is preferable, and can further improve the cleanliness after use by preventing the liquid from staying on the strip (5).Such a swollen strip (5) has a perforation with a concave top surface. It can be obtained by using small protrusions.

In addition, when using small cylindrical perforation protrusions with approximately the same diameter in the height direction, a strip (5) of approximately the same size as the opening of the pore <3> is formed in the nonwoven fabric (as shown in Fig. 7). 2) and the color of the liquid absorbed by the absorbent core material becomes the film <1>
It is less visible from the side, making it convenient as a surface material for sanitary napkins.

(Effects of the Invention) As described above, the composite sheet (7) for surface material of an absorbent product according to the present invention consists of an opaque heat-adhesive film (1)
and a heat-adhesive thin nonwoven fabric <2> are thermally bonded to form a large number of pores (3) on the surface of the film (1), and when the pores (3) are formed, the pores are Strips extruded from (5)
is depressed from the surface of the film (1) and is thermally bonded to the nonwoven fabric (2), and an annular ring is formed between the inner periphery of the pore (3) and the outer periphery of the strip (5). Since the gap (6) is formed, when this composite sheet (7) is used as a surface material for absorbent products such as sanitary napkins and disposable diapers, the sewage discharged from the surface side of the film (1) is It passes through the annular gap (6) from a large number of pores (3), passes through the nonwoven fabric (2), and smoothly flows into the absorbent core material and is absorbed.
There is almost no remaining liquid on the film surface, and the liquid does not return to the film side, eliminating the unpleasant damp feeling during wear. Furthermore, since there are small pieces (5) separated from the film at the bottom of the depression (4) of each pore (3), dirt on the absorbent core material is difficult to see from the film side after use, giving a feeling of uncleanness. can be resolved.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, and include the first embodiment.
Figure 2 and Figure 2 are an enlarged cross-sectional view and partial plan view of the composite sheet, Figure 3 is a schematic diagram of the method for manufacturing the composite sheet, Figure 4 is an enlarged view of the main part of Figure 3, Figures 5 and 6. FIG. 7 and FIG. 7 are enlarged cross-sectional views showing other aspects of the perforation. 1: Heat-adhesive film 2: Heat-adhesive nonwoven fabric 3: Pores
4: Hollow 5: Strip 6: Annular gap 7: Composite sheet

Claims (1)

[Claims] A opaque heat-adhesive film and a thin heat-adhesive nonwoven fabric are heat-adhered to form a large number of pores on the surface of the film. A surface of an absorbent product characterized in that a piece is thermally bonded to the nonwoven fabric by sinking in from the film surface, and an annular gap is formed between the inner circumferential edge of the pore and the outer circumferential edge of the strip. Composite sheet for materials.