JPH03297464A - Surface material sheet for body fluid absorbing article and the absorbing article - Google Patents

Abstract

PURPOSE:To give a dry and smooth feeling to the skin and to prevent a body fluid absorbed by a core material from being returned through a non-porous part, by forming a woven fabric from a hydrophobic textile having one surface which is smoothened by a hot roll so as to restrain its gas permeability. CONSTITUTION:One surface of a thin web having a METSUKE (unit weight) of 15 to 50g/cm<2> and made of a thermoplastic textile is treated by a hot roll at a temperature in the vicinity of the softening temperature of the textile so as to be smoothened film-likely, and the other surface thereof is treated at a temperature lower than the softening temperature of the textile so as to obtain an unwoven fabric having a specific volume by which its textile configuration is held on the other surface. Several pores 2 having a numerical aperture of 10 to 45% and each having 0.5 to 1.8mm<2> are formed in the unwoven fabric at the surface on which the configuration of the textile is held, by several heated small projections while the inner peripheral edge of each pore is projected on the rear surface side, and accordingly, a suitable gas permeability is held in a non-porous part. With this arrangement, a dry and smooth feeling is given to the skin which wears the fabric, and a stuffy condition until the absorption of a human fluid is started is eliminated, thereby it is possible to successively and smoothly absorb the human fluid.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a porous surface material sheet applied to the skin-contacting surface of body fluid absorbent articles such as sanitary napkins and disposable diapers, and body fluid absorbent articles. be.

(Prior art) As is well known, body fluid absorbent articles such as sanitary napkins and disposable diapers are made of a water-absorbent core material made of wood valves, rayon, cotton, or these water-absorbing materials containing a water-absorbing polymer, and the back surface of the absorbent core material. It consists of a leak-proof sheet placed on the side and a surface material sheet placed on the side that comes into contact with the skin. This surface material sheet was designed to meet the characteristics required by the user, namely, good liquid permeability, little liquid return, no damp or stuffy feeling during use, and dirt that is difficult to see after use. Various attempts have been made.

As this surface material sheet, for example, Japanese Patent Publication No. 57-70
There are a film type as seen in Japanese Patent Application No. 81-6 and a non-woven fabric type as seen in Japanese Patent Application Laid-Open No. 62-276002.

(Problem to be Solved by the Invention) However, when a perforated film is used as the surface material sheet of an absorbent article as in the former case, liquid absorption toward the absorbent core material side is good, and liquid absorption from the absorbent core material is also good. However, the air permeability of the non-porous surface of the absorbent article deteriorates, and the product feels stuffy until the absorbent liquid begins to be absorbed, and this stuffiness impairs dryness. It will be. On the other hand, the latter type of body fluid absorbent article using a nonwoven fabric that has been treated with accumulated water as a surface material sheet and has a large number of holes has a better feel to the skin than the former film, and the number of openings is 7 to 7. Since it is relatively large at 50III112, it has good body fluid absorption properties. However, even if accumulated water is treated, moisture in non-opening areas is unavoidable.
Further, since it is extremely difficult to make the opening for liquid passage small, the effect of suppressing liquid return is small, and drying properties are difficult.

The present invention provides a surface material sheet and a body fluid absorbent article that have the respective advantages of the above-mentioned film surface material sheet and nonwoven fabric surface material sheet, and have their disadvantages improved.

(Means for Solving the Problems) The surface material sheet in the body fluid absorbent article according to the present invention includes:
Although it is a non-woven fabric, one side, which is the back side, is smooth and liquid permeability is suppressed, and the other side, which is the front side, is more flexible than the other side and has an appropriate amount of breathability. It is equipped with a large number of pores for liquid passage toward the absorbent core material toward the back side. That is, the fabric weight made of thermoplastic fibers is 15 to 5.
One side of the 0g/m2 thin web is treated with a heated roll at a temperature near the softening point of the fibers to smooth it into a film, and the other side is treated at a temperature lower than the softening point of the II&fibers to form m fibers. Specific volume with shape maintained 1 to 15 cr
A/g nonwoven fabric, which is opened by a large number of small protrusions heated from the side of the nonwoven fabric that maintains its fiber form] θ ~ 45%, one hole diameter 0.5 ~ ],,8
It is characterized by having a large number of pores of mm2 in size, with the inner peripheral edge of each pore protruding toward the back side, and maintaining appropriate air permeability in the non-porous area, and body fluids. In the absorbent article, a leak-proofing material impermeable to bodily fluids is arranged on the back side of the absorbent core material, and the above-mentioned surface material sheet is arranged on the front side of the absorbent core material, and the surface material sheet is The protruding edges on the back side of each pore are arranged in close contact with the absorbent core material.

Examples of the thermoplastic fibers constituting the surface material sheet include hydrophobic fibers such as polyester, polypropylene, polyethylene, and polymethylpentene, and core-sheath composite fibers with a polypropylene core and polyethylene or polymethylpentene sheath. In particular, the above-mentioned composite fibers having excellent thermal adhesive properties are suitable. In addition, the fiber thickness of nonwoven fabric is 0.1
~8 denier, a basis weight of 15 to 50 g/1ll12, and a specific volume of about 1 to 15 crn3/g are preferable, especially a basis weight of 15 to 30 g/m2 and a specific volume of 3 to 6 cm.
'7g nonwoven fabric is preferred.

When the refined fiber is thicker than 8 denier, the nonwoven fabric becomes rough and feels uncomfortable to the touch, and the fabric weight is 1.5 g/m2.
If it is smaller than , body fluid permeation occurs from parts other than the pores,
When the basis weight is 50 g/m2 or more, the thickness of the surface material sheet becomes large and bulky, resulting in a stiff feeling. When the specific volume is larger than 15 cm'/g, the air permeability increases and body fluids can pass through. Conversely, when the specific volume is less than 1 cm'/g, it becomes paper-like and hard, and the air permeability becomes extremely low. descend.

To obtain a nonwoven fabric with appropriate air permeability (1 to 100 MJ/cm2/sec) from a fiber web with a basis weight of 15 to 30 g/m2, a smooth roller heated to a temperature from the softening point of the fibers to around the melting point and softening of the fibers are required. The fibrous web is pressed and heated using a smooth roller with a temperature lower than the point.
This can be achieved by smoothing one of the surfaces of the nonwoven fabric into a film. In order to create a large number of pores in a nonwoven fabric that has been thermally processed using a smooth roller, it is possible to create pores in the shape of a truncated cone, truncated pyramid, cylindrical or prismatic shape, etc., each having small projections whose height is larger than the thickness of the nonwoven fabric. Between a pair of rollers consisting of a perforated roller and a smooth roller with a soft surface, the circumferential surface of which is provided with a large number of small protrusions each having a top surface, the small protrusions are heated to a temperature higher than the fiber softening temperature "i". supplying the side of the nonwoven fabric with its fiber morphology maintained as the small protrusion side;
It is preferable to pass through the small protrusions of the perforation roller through the nonwoven fabric by passing the small protrusions between the small protrusions without touching the nonwoven fabric, as if by embossing.
Stable pores with a heat-set shape are obtained by softening or melting the fibers of the nonwoven fabric, and the inner edges of the resulting pores protrude from the back side of the nonwoven fabric, and the side surface is larger than the thickness of the nonwoven fabric. It becomes a pore with .

The size, shape, distribution density, or aperture ratio of this pore is
Body fluid-absorbent articles are selected depending on their intended use, but for articles in the field of sanitary materials such as sanitary napkins and disposable diapers, materials that have the ability to pass through body fluids, suppress the return of body fluids that have passed through them, and Considering the concealment of passing body fluids, etc., 1
The opening area on the surface side of each hole is approximately 0.5 to 1.8 m+n
2. The opening area on the back side is approximately 0.2 to 1.2 mm2, the dimension in the thickness direction of the hole (hereinafter referred to as the height of the hole side surface) is more than twice the thickness of the nonwoven fabric, and the taper angle of the hole is 15 to 40 mm. degree, and the open area ratio of many pores to the nonwoven fabric surface is 15 to 40.
% is desirable.

(Function) A nonwoven fabric made of hydrophobic fibers whose one surface is smoothed by a heating roll and whose air permeability is suppressed restricts the permeation of body fluids while the other surface retains the flexibility characteristic of nonwoven fabrics. Therefore, if this nonwoven fabric is treated with holes on its flexible side and used as a surface material sheet for body fluid absorbent articles with its flexible side as the surface, it will give dryness and a smooth feeling to the skin, and will reduce the absorption of liquids from wearing. Eliminate stuffiness before starting. The numerous pores in the surface material sheet introduce body fluids into the absorbent core material, and the inner periphery of each pore protruding toward the back side firmly adheres to the absorbent core material, promoting the introduction of body fluids. A gap is created between the nonwoven fabric portion between the pores and the absorbent core material, and the film-like smoothing on the back side prevents body fluids absorbed into the core material from returning from the non-porous portion.

(Example) Example 1. Composite fiber (1,5D) whose sheath component is polymethylpentene (melting point 230℃, softening point 145℃) and whose core component is polypropylene (melting point 167℃).
A card web of 51mm x 51mm is intertwined using the water needling method to form a nonwoven fabric with a basis weight of 28g/■2, and then this nonwoven fabric is pressed with a pair of smooth rollers heated to 150°C and 90°C, and a high temperature smooth roller is used. Thickness 0.09 mm with the side smoothed into a film and the low temperature smooth roller side maintaining the fiber form, specific volume M3.2c+a3/g
A densified nonwoven fabric (10) with an air permeability of 2.1 mJl/cwr2/sec was obtained. As shown in FIG. 4, a large number of small truncated conical projections 11
1) and a smooth roller (13) having a flexible outer circumferential surface arranged one above the other.
The nonwoven fabric (10) is rotated in the direction of the arrow while being heated to 20°C, and the nonwoven fabric (10) is transferred from one side of the device to the side (I
OA) on the perforating roller side, and the film-like smoothing side (I
Both rollers (12) (13) with OB) as the smooth roller side
As shown in FIG. 4, the surface (] of the nonwoven fabric (10) is applied to the portion (IIB) between the protrusions (11) (11).
A large number of pores (2) (2) were bored in the nonwoven fabric (10) without contacting with A) to obtain a surface material sheet (1).

The surface material sheet (1) thus obtained has the above-mentioned small protrusions (11) per unit area as shown in FIGS. 1 and 2.
The aperture ratio according to (11) is 32%, the area of the opening (2A) on the front side of one pore 2) is 1.13 mm on average, the area of the opening (2B) on the back side is 0.50 mm on average, each pore ( 2
) where the inner peripheral edges of the pores protrude toward the back side and the height (H) of the pore side surface is an average of 0.7111 m.
) (2), and each pore (2) (2) is heated by the punching roller (12), so that the fibers in the part forming the hole are harder than in other parts, resulting in a hole shape. is stable,
? The non-porous part on the front side had more flexibility than the back side.

This surface material sheet (]) has a specific volume of 1.3 cm'/g,
Absorbent core material made of crushed wood with an apparent thickness of 8 mm (
3), and a 0.35 μm thick polyethylene film leakproof material (4) was placed on the back side to form a sanitary napkin (5) as shown in FIG.

Similarly, as shown in Tables 1 and 2, the surface materials of Examples 2 to 6, Comparative Example 1 (conventional film type), and Comparative Example 2 (conventional nonwoven fabric type) were used for sanitary use in the same manner as in Example 1. A test was conducted to compare the performance of napkins and napkins.

The results are shown in Table 3.

(Margins below) Table 1 The processing temperature in Table 1 indicates the temperature of the upper and lower smooth rollers in the press processing device for nonwoven fabric (10). Bond (product name PS106')
As the film of Comparative Example 1, a polyethylene film (trade name Bolam 20) manufactured by Nisan Soda (It) was used.

The fibers in Comparative Example 2 were the same as in Example 3.The air permeability in Table 2 is the value measured for the nonwoven fabric and film before perforation using a Frazier air permeability tester in accordance with JIS-L-1079. It shows and is.

The test methods for the items in Table 3 are as follows.

1) Liquid absorption time: Lay the leakage preventive material under the absorbent core material, place each surface material sheet in Table 1 on top of the absorbent core material, and absorb the liquid at 6.8 g/c.
Ff of yn2 10 ml of artificial menstrual blood is dropped from the top of the surface material sheet under the weight, and the time it takes for the artificial menstrual blood to be absorbed into the absorbent core material.

2) Amount of liquid returned After absorbing the artificial menstrual blood above, leave it for 1 minute, place three weighed filter papers (7cm x 7cm) on top of the surface material sheet, and apply a load of 28g/cm2 to the entire surface. After addition, the weight of the filter paper was measured after leaving it for 1 minute, and the amount of liquid returned was calculated.

3) Shielding properties After the artificial menstrual blood was absorbed into the absorbent core material, the state was visually observed from the surface material sheet side and classified into the following grades.

Grade 4: The color of artificial menstrual blood is hardly noticeable.

Grade 3: The color of artificial menstrual blood is slightly visible.

Grade 2: The color of artificial menstrual blood is quite visible.

Grade 1: The color of artificial menstrual blood appears to be unpleasant.

4) Stuffy feeling Each of the absorbent articles of Examples 1 to 6 and Comparative Examples 1.2 was heated to a humidity of 90%.
%, placed in a constant temperature bath at a temperature of 37℃ for 2 hours.
A hand was placed in a constant-temperature bath and the absorbent article was directly touched, and the wetness of the surface was judged as stuffiness.

In addition, as artificial menstrual blood, 20% glycerin, 798% distilled water
% and Congo Red 0.2%.

(Effects of the Invention) As described above, although the surface material sheet in the body fluid absorbent article of the present invention is a nonwoven fabric, one surface, which is the back side, is smoothed and liquid permeability is suppressed, and the other surface, which is the front side, is smoothed. One side is more flexible than the other, has an appropriate amount of air permeability, and is equipped with a large number of pores for liquid passage from the front side to the back side to the absorbent core side. The surface side feels nice to the touch, and the liquid passes through the pores well. Therefore, body fluid absorbent articles made using this surface material,
It provides a dry and smooth feeling to the bottle while being worn, and also eliminates stuffiness until body fluid absorption begins, and the inner edges of each pore protruding from the back side are firmly in contact with the absorbent core material. The introduction of body fluids into the absorbent core material through the pores can be promoted, and body fluids can be smoothly absorbed one after another. Furthermore, the protrusion of the inner periphery of the pores eases the degree of adhesion between the back surface of the non-porous part of the surface material sheet and the absorbent core material, and since the back surface side is smoothed like a film, body fluids absorbed into the core material can be absorbed. This prevents the liquid from flowing back to the surface side from the non-porous part of the product, eliminating the sticky feeling during use and eliminating the unclean feeling after use.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a partial perspective view of a surface material sheet, FIG. 2 is an enlarged cross-sectional view of the surface material sheet in the thickness direction, and FIG. 3 is a view of a sanitary napkin. An enlarged cross-sectional view, FIG. 4 is a side view schematically showing a method of perforating the surface material sheet, and FIG. 5 is an enlarged view during perforation.

Claims (1)

[Claims] 1) One side of a thin web made of thermoplastic fibers with a basis weight of 15 to 50 g/m^2 is treated with a heating roll at a temperature above the softening point of the fibers to smooth it into a film, The other side is treated at a temperature lower than the softening point of the fibers to maintain the fiber morphology, resulting in a nonwoven fabric with a specific volume of 1 to 15 cm^3/g, and heating is performed from the side of the nonwoven fabric that retains the fiber morphology. A large number of pores with an aperture ratio of 10 to 45% and a size of 0.5 to 1.8 mm^2 are created by the large number of small projections, and the inner peripheral edge of each pore is on the back side. A surface material sheet for a body fluid absorbent article, characterized in that it has protrusions. 2) A leak-proof material impermeable to body fluids is arranged on the back side of the absorbent core material, and the facing material sheet according to claim 1 is arranged on the front side of the absorbent core material, so that each of the facing material sheets A body fluid absorbent article characterized in that the protruding edges of the pores on the back side are in close contact with the absorbent core material.