JPS62170565A - Surface material of absorbable article and its production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a surface material for absorbent articles used for treating body fluids, such as disposable diapers, incontinence pads, and sanitary napkins, and a method for manufacturing the same.

(Prior Art) The following types of surface materials for absorbent articles of this type are mainly known and have been or are currently in practical use.

(1) Nonwoven fabric whose main component is hydrophilic fibers This is a nonwoven fabric whose main component is hydrophilic fibers such as rayon, which improves the permeability of body fluids. A large amount of body fluid remains on the surface of the nonwoven fabric, and the surface that comes into contact with the wearer's skin is always wet.

(2) A nonwoven fabric with a two-layer structure, in which the surface component is hydrophobic fiber and the bottom layer component is hydrophilic taia.
Since the surface is made of hydrophobic fibers, it is possible to improve the above drawback (1) to a certain extent, but the surface layer must be made as thin as possible to avoid impairing the permeability of body fluids. Therefore, the above-mentioned effect has not improved much and is still not satisfactory.

(3) A non-woven fabric made only of hydrophobic fibers, to which a drug that imparts hydrophilicity is attached.Although this has an improvement effect on the drawbacks of (1) and (2) above, it is also difficult to absorb body fluids. The hydrophilic drug is washed away by the permeation of the body fluid from the second time onwards, and from the second time onwards, it becomes difficult for the body fluid to permeate.

(4) A flexible thermoplastic film with a large number of holes formed by ripening, and a fiber layer bonded to the bottom surface of the film with an adhesive.
, (2), and (3) are remarkable, but since the non-perforated part has no air permeability and does not allow moisture generated on the skin surface to pass through, the surface becomes stuffy.
It lacks a cloth-like feel (as it descends, it gives an unpleasant cool feeling to the skin, especially in cold weather).

(Problems to be solved by the invention) The characteristics required for the surface material of this type of absorbent article are that it has quick permeability to body fluids, and that it leaves a wet feeling on the surface of the surface material after body fluids have permeated through it. In other words, it has a dry feel on the skin (dry touch), it has the ability to prevent body fluids from returning (rewetting) due to pressure on the surface material that is permeable to body fluids, and it feels good on the skin when worn. One thing can be mentioned.

The above-mentioned characteristics are mutually contradictory, but as is clear from the above-mentioned drawbacks, the above-mentioned prior art is not capable of satisfying each of the above-mentioned characteristics at the same time by adjusting or controlling them well.

(Means for Solving the Problems) Therefore, an object of the present invention is to provide a surface material for an absorbent article that can simultaneously satisfy each of the above characteristics.

The present invention provides a surface material for an absorbent article that is a perforated nonwoven fabric, in which the U&fiber composition is composed of hydrophobic fibers of 70 to 100% by weight2 and hydrophilic fibers of 0 to 30% by weight, and the 1" I12 and the size is 0.29 to 30ff
i! 02, the porosity is 10 to 60 $ of the surface area, and the non-porous area has a substantially uniform density and is liquid impermeable. Exists in wood.

Furthermore, the present invention provides a surface material for an absorbent article that is a composite nonwoven fabric comprising a surface layer in contact with the user's skin and a back layer thereof, which have different fiber compositions; is hydrophobic fiber 70-100t and hydrophilic fiber M
Consists of 10 to 30 weight Bx, with a basis weight of at least 15g
/m2, and the size is 0.29~30IIll! 12
a large number of pores, the pores are 10 to 6 oz of the area of the surface layer, and the non-porous area has a substantially uniform density and is liquid impermeable. : The back layer has a fiber composition of hydrophilic fibers of 50 to 100 weight 2 and hydrophobic LA fibers of 0 to 60 weight 2, with 1" being 5 to 50.
g/m2 and is non-porous.

Furthermore, the present invention provides the surface layer and the back layer,
The fibrous web is obtained by treating the fibrous web with a high-speed water jet and then joined together, or the surface layer is obtained by the jetting treatment, while the back layer is obtained by fusing the fibers of the fibrous web and joined together. Therefore, the present invention resides in a method of manufacturing the surface material.

(Detailed Description of the Invention) Further, the present invention will be described based on embodiments as follows.

As shown in FIGS. 1 and 2, the surface material 1 is made of non-woven fabric and has a large number of apertures 2 arranged appropriately to form a pattern, thereby achieving the intended purpose of the present invention. In Ue, the fiber composition consists of hydrophobicity 100 fiber weight 2, and the basis weight is 15 g/mz or more, preferably 20 to GO g/m2,
Density 0.03 g/cm3 or more, preferably 0.1 to 0
．． 5g/cm3.18 degrees 0.2-2d, preferably 0.
5 to ld, and the non-porous region 3 has a substantially uniform density and is substantially liquid-impermeable. However, even if it contains some hydrophilic fibers, it is unlikely to harm the intended purpose, and its permissible content is at most 30%. In addition, in order to achieve the intended purpose, 1511 hole 2 is
The size is 0.29 to 30 mm2, preferably 0.35
~11 ml112, the pore size is 10 to 60%, preferably 20 to 50%, and the fibers at the periphery of the apertures 2 are distributed without protruding to the -1- plane, that is, It is preferable from the viewpoint of strength, feel, appearance, etc. that the fibers be formed by being pushed or scraped apart, and in order to achieve this, the fibers are entangled and pores are provided by a high-speed water jet using a support described later. It is preferable.

The surface material 1 is preferably made into a non-woven fabric by intertwining fibers. Such a nonwoven fabric can be obtained by intertwining the fibers of a predetermined fibrous web, which is the material of the nonwoven fabric, on a support by spraying a high-speed water jet. Such a nonwoven fabric can be obtained by interlacing the fibers of a predetermined fibrous web, which is the material of the nonwoven fabric, on a support using a high-speed water jet treatment. Preferred methods include JP-A-55-71853 and JP-A-57-302 filed by the present applicant.
88 and Japanese Patent Application Laid-Open No. 59-125954.

The surface material shown in FIG. 3 consists of the surface material 1 and the back layer 4. Hereinafter, when the surface material 1 is described in relation to the back layer 4, it will be referred to as the surface layer 1. surface layer l
Although the intended purpose of the present invention can be achieved even when used without providing the back surface M4, it is preferably used in combination with it.

The back layer 4 has a fiber composition of hydrophilic fibers of 100% by weight, a basis weight of 5 to 50 g/a+2, and a density of 0.01 to 0.2 g.
/cm3.

Preferably 0.02 to O.07g/c1. Fineness 0.7~
15d, preferably 3-8d. However, one surface layer l
The size of the aperture 2, its aperture ratio,! It depends on the degree etc.
Even if it contains up to 60% by weight of hydrophobic fibers, it will not impede the intended purpose, and on the contrary, it may be preferable to contain some of it in terms of elasticity retention under wet conditions. Like the surface layer 1, the back layer 4 is also preferably made into a non-porous nonwoven fabric by interlacing the fibers by the method described above, but this is formed by fusing the fibers by heat and pressure treatment. It doesn't prevent you from being what you are. When formed by such fusing, some or all of the hydrophobic fibers included in the back layer 4 are heated to a temperature of 90 to 140°C.
Preferably, it is a heat-sealed mfa of °C. Then, the surface layer 1. The most preferable method for forming the back layer 4 into a non-woven fabric and compositing them into a single body is to
After fiber entangling the fiber web to be obtained by the above method,
A fiber web to be formed as the back side M4 is overlaid on this, and the web is again entangled with the fibers using the above method, and at the same time, the fibers are entangled with the surface layer 1, and the fibers are made into fibers using the above method. A fiber web containing the heat-fusible Mll fibers to be used as the surface layer 4 is superimposed on the surface layer 1, and the web is subjected to pressure treatment in the presence of the temperature to simultaneously fuse the fibers. A method of fusing fibers to the surface layer 1 may be mentioned. In the case of the former method, as illustrated in FIG. ! : Some of the fibers with the back layer 4 are mixed and the boundaries between these layers are not clearly defined. However, in the case of the latter method, as illustrated in FIG. Since the fibers are fused primarily in the overlapping areas of these layers, the boundaries are relatively clear.

If a method of fiber entanglement is used to form the surface layer l,
It is very convenient to form the apertures 2 by distributing the fibers. That is, it can be formed by intertwining the fibers of the fibrous web to be the surface layer 1 with a high-speed water jet jet treatment on a support having aperture-forming elements, and at the same time distributing the fibers using the aperture-forming elements. .

Hydrophobic fibers for the surface layer 1 include polyester, polypropylene, polyethylene, acrylic, polyurethane, etc.; 5 examples for the surface layer 4 include synthetic fibers such as polyester whose fiber surface has been treated with parent wood, rayon, cotton, etc.; and They can be used alone or in combination, but preferably polyester fibers are used as the surface layer 1, and polyester fibers whose surface has been treated to be hydrophilic are used as the back layer 4. This processed polyester fiber is, for example,
It is preferable to use a treatment agent obtained by the method for manufacturing a treatment agent for polyester molded articles disclosed in No. 81 to make it hydrophilic.

To mention a particularly important point among the numerical values specified in the present invention, if the basis weight of the surface layer 1 is 15 g/m2 or less and the density is 0.03 g/c+a3 or less, the impermeability of body fluids and the prevention of backflow are sufficient. The basis weight of back layer 4 is 50.
g/a+2 or more, and the density is 0.2 g/c+a3 or more, the permeability of body fluids from the openings 2 is low, and the openings 2 of the surface layer l
If the size is 0.29 ma + 2 or less and the porosity is 10% or less, the permeability of body fluids from the pores 2 is poor, and the pores have a size of 30 mm or more and the porosity is 90 % or more, the surface layer 4 of the pores will come into direct contact with the skin, or body fluids will flow back through the pores, giving a moist feeling to the skin. In addition,
The basis weight and density of the surface layer 1 are approximately 40g/
+2 or more and 0.53/cm3 or more, there is no particular difference in the function of the surface layer 1, so for economic reasons, the values are up to 60 g/m2 and 0.5 g/C113, respectively. It is better.

Surface layer 1 and back layer 4 of nonwoven fabric as the surface material of the present invention
In order to intertwine the fibers and form open pores,
A conventionally known high-speed water jet jet treatment device may be used, but
Preferably, the apparatus shown in FIGS. 7 to 9 is used. 7th
In the apparatus shown in the figure, a belt conveyor 20, a water film supply means 21, a first support roll 22, a water jet treatment means 23 disposed opposite thereto, and a belt conveyor 24.
, a second support roll 25 having an aperture-forming element, water jet treatment means 26 disposed facing each other at a predetermined interval in the circumferential direction thereof, and a pair of squeezing rolls 27 . The water film supply means 21 is provided to constantly overflow a fixed amount of water from the tank 2 and flow it down through the inclined plate 29 to form a water film and supply it to the fiber web 30. As a result, the second support roll 25 can effectively perform the fiber entanglement treatment while suppressing the fuzz of the fibers of the fiber web 30 and stabilizing the texture.
As shown in FIGS. 8 and 9, the cylinder is formed into a cylinder having a predetermined diameter and length, and has a large number of protrusions 31 dotted at predetermined intervals on the smooth surface of the cylinder as aperture forming elements. It also has a large number of small drainage holes 32 on the plane between the protrusions. The protrusions 31 have a small area at the top of the protrusions 31 and extend toward the base in order to increase the efficiency of forming holes in the fiber web 30 and to make it easier for the formed nonwoven fabric to be peeled off from the second support roll 25. It is preferable that the shape gradually widens, for example, a hemispherical shape. The diameter, area ratio, and arrangement shape of the protrusion 31 approximately correspond to those of the opening 2, but the height is 0.4 to Ifl.
+m is preferable in order to provide clear pores 2 to the nonwoven fabric.The first support roll 22 is not shown in detail, but has a diameter of 0.2 to 1.0m+a and an area ratio of 2.5. It is preferable that a large number of small drainage holes of up to 30% are arranged at predetermined intervals. Also, although not shown,
Inside the first support roll 22 and the second support roll 25,
In order to improve the drainage efficiency on the roll surface, it has a predetermined hardness so that it collides with the roll surface to form a repulsion flow, which can again act on fiber entanglement.

The fibrous web 30 is placed on the first support roll 22 at = L stage 23
The fibers are preliminarily entangled by a water jet from each means 28, and then the fibers are fully entangled by a water jet from each means 28 on the second support roll 25. At the same time, each protrusion 31
The fibers are distributed through the aperture treatment. The back pressure of the water flow is preferably 20 to 100 kg/cm2, and if it is less than 20 kg/cm2, energy sufficient to entangle the fibers will not be obtained, resulting in insufficient fiber entangling efficiency and strength. If this is the case, the cost increases, which is commercially disadvantageous, and the texture of the NA fiber web 30 is likely to be disturbed. Also, lockstitch is 0.5-201/Q1
It is preferable to have 2 teeth, and 0.5 f1. /m2 or less, the fiber efficiency and strength are insufficient as described above. The amount of water is determined by the injection pressure and the diameter and number of orifices discharged into the water jet means 23. 28, but even if it exceeds 20 sentences/m2, the fiber entanglement efficiency and strength will not improve in proportion to the amount of water, which is economically disadvantageous. It is.

In the case where the back layer 4 of the nonwoven fabric, which is the surface material of the present invention, is preferably fused, forming a nonwoven fabric by such fiber fusion is an old technique well known to those skilled in the art. There is no need to explain it.

Surface materials having the above-mentioned structure are used for absorbent articles such as disposable diapers, incontinence bands, and sanitary napkins, as illustrated in FIG. It is constructed by placing the surface layer 1 on the upper surface of an absorbent body 5 mainly made of wood pulp, and placing a water-impermeable sheet 6 such as a plastic film on the lower surface. Construction is done in the manner disclosed in known articles of this type.

(Function) As shown in Fig. 6, when the surface material is used in an absorbent article, when body fluid is excreted into the surface area of the surface layer l, the surface material is discharged from each opening 2 in the surface area to the back surface. It passes through the layer 4 and is absorbed by the absorber 5. The absorbed body fluid can be absorbed by the surface layer l being substantially liquid-impermeable, and the r3F4 pores 2 having a maximum size of 30 mm.
2. Since the porosity is at most 50%, there is little chance of backtracking from the surface material. Depending on the method of combining the surface layer 1 and the back layer 4, the back layer 4 may appear raised in the opening 2, but even in that case, it is retracted from the surface of the surface layer l, so even if the back surface Even if the layer 4 is wet with body fluids, the back layer 4 rarely comes into direct contact with the skin. Furthermore, since all of the fibers forming the surface layer 1 are intertwined or only some of the fibers are fused, the surface layer 1 has air permeability not only in the apertures 2 but also in the entire surface material.

(Example) As shown in Table 1.

Table 2 shows the performance of the examples shown in Table 1 and the performance of comparative examples.

Comparatively, No. 1 is the surface material used by the present applicant for disposable diapers, which is made of 30g/a2 consisting of 50% by weight of rayon fibers of 1.5dX 5mm and 50% by weight of polyester fibers fa of 1.4dX 44a+m. It is a non-woven fabric with a ma'9. It is formed by intertwining them.

Comparative Example 2 is a surface material used by Company A for disposable diapers, which is made of a 25 g/m2 polyethylene film and has a large number of holes of 0.5 mmφ and 1 mm intervals, and its porosity is is 20%.

The performance shown in Table 2 was based on the following test method.

(1) Sample (surface material) on the top surface of the absorbent body made of permeable cotton-like wood pulp.
The artificial urine 5n+1 in the beaker was poured over it all at once, and the number of seconds required for it to completely penetrate the sample was measured.

(Rewetting property) A sample was placed on the upper surface of an absorbent body made of 100 cm2 of cotton-like wood pulp, and after pouring 5 times the weight of Biulet artificial urine on the absorbent body, a 100 cm2.
A 7 kg flat plate weight was applied, the weight was removed after 3 minutes, and the amount of artificial urine adhering to the artificial skin sheet was measured.

(3) Dry touch property After the above rewet measurement, the sample was touched with the palm of the hand to test its wetness.

(Effects of the Invention) Since the surface material according to the present invention has the above-mentioned structure and function, it simultaneously satisfies contradictory properties such as quick permeability of body fluids, dry touch properties, anti-irritability properties, texture, and breathability. It is possible to achieve the intended purpose. In addition, the openings that serve as the parts for guiding body fluid permeation are formed by distributing the fibers, that is, without partially cutting the fibers. The fibers do not become frayed, fuzzed, or damaged, and the strength of the entire surface layer that comes into contact with the skin is always maintained.

Furthermore, in the manufacturing method according to the present invention, particularly when forming the m-spring-4 surface material by intertwining fibers with a high-speed water jet treatment, the surface layer and the openings can be formed at the same time, and further, Since the formation of the back layer and the bonding of this layer to the surface layer can be performed simultaneously, the manufacturing method is relatively simple and suitable for low-cost mass production of the surface material.

Furthermore, the obtained surface material is a so-called binder-free nonwoven fabric in which no fiber binder is used, so it is extremely suitable for practical use, particularly as a diaper for infants.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the surface material of the present invention. FIG. 2 is a partially enlarged perspective view of the surface material. FIG. 3 is a partially enlarged perspective view of another surface material of the present invention. FIG. 4 is a partially enlarged cross-sectional view schematically showing a state in which the front layer and back layer of the surface material shown in FIG. 3 are manufactured by a high-speed water jet treatment and are bonded together. FIG. 5 is a partially enlarged cross-sectional view schematically showing the state in which the bonding is performed by heat-pressing treatment. FIG. 6 is a partially cutaway perspective view of the surface material shown in FIG. 2 applied to an absorbent article. FIG. 7 is a schematic side view showing an example of an apparatus for manufacturing the surface material by spraying a high-speed water jet. FIG. 8 is a schematic perspective view of a support roll with aperture-forming elements arranged in the device; FIG. 9 is a partially enlarged plan view of the support roll. 1...Surface material (surface layer) 2...Open hole 3...Non-hole area 4...Back layer 25...Support roll 31...Open hole forming element Fig. 4 Fig. 5 Figure 6

Claims (17)

[Claims] (1) In the surface material of an absorbent article that is a nonwoven fabric; the fiber composition is 70 to 100% by weight of hydrophobic fibers and 0% of hydrophilic fibers.
~30% by weight, with a basis weight of at least 15g/m
^2, has a large number of pores with a size of 0.29 to 30 mm^2, the porosity is 10 to 60% of the surface area, and the non-porous area has substantially no density. The above-mentioned surface material is characterized in that it is uniform and liquid-impermeable. (2) The surface material of an absorbent article according to claim 1, wherein the openings are formed by distributing fibers. (3) The surface material of the absorbent article according to claim 1, which is formed by intertwining fibers. (4) The surface material of the absorbent article according to claim 1, which has a fineness of 0.2 to 2 d and a density of 0.03 g/cm^3 or more. (5) In the surface material of an absorbent article, which is a composite nonwoven fabric that has different fiber compositions and is composed of a surface layer that forms the surface that comes into contact with the user's skin and a back layer that forms the back surface of the surface layer; The layer has a fiber composition of 70 to 100 hydrophobic fibers.
% by weight and 0-30% by weight of hydrophilic fibers, has a basis weight of at least 15 g/m^2 and a size of 0.29
It has a large number of pores of ~30 mm^2, the porosity is 10 to 60% of the surface area of the first layer, and the non-porous area has a substantially uniform density and is impermeable to liquid. The back layer has a fiber composition of 50 to 100% by weight of hydrophilic fibers and 0 to 60% by weight of hydrophobic fibers, and has a basis weight of 5 to 5%.
0 g/m^2 and non-porous. (6) The surface material of an absorbent article according to claim 5, wherein the openings are formed by distributing fibers. (7) The surface layer and the back layer are each formed by intertwining fibers, and the fibers of both layers are intertwined to form an integral composite. surface material for absorbent articles. (8) The surface material for an absorbent article according to claim 5, wherein some or all of the hydrophobic fibers contained in the surface layer are heat-fusible fibers that melt at a temperature of 90 to 140°C. (9) A patent claim in which the surface layer is made into a non-woven fabric by intertwining fibers, and the surface layer is made into a non-woven fabric by fusing the fibers, and is integrally composited with the surface layer. The surface material of the absorbent article according to item 8. (10) The fibers of the surface layer have a fineness of 0.2 to 2 d and a density of 0.03 g/cm^3 or more, and the fibers of the back layer have a fineness of 0.7 to 15 d and a density of 0.03 g/cm^3 or more. 01~0.
The surface material of the absorbent article according to claim 5, which has a surface material of 2 g/cm^3. (11) The fiber composition of the surface layer is hydrophobic fiber 70-1
00% by weight and 0 to 30% by weight of hydrophilic fibers,
A first fibrous web having a basis weight of at least 15 g/m^2 is formed into a non-woven fabric by imparting pores with a size of 0.29 to 30 mm^2 and a porosity of 10 to 60%, and then , the fiber composition of the surface layer is hydrophilic fiber 50-1
00% by weight and 0 to 60% by weight of hydrophobic fibers,
Absorbency characterized in that a second fiber web having a basis weight of 5 to 50 g/m^2 is layered on the surface layer to form a non-porous nonwoven fabric to form a back layer, and at the same time, the two are composited together. Manufacturing method for surface materials of articles. (12) The surface layer is formed by jetting the first fiber web with a high-speed water jet on a support having aperture-forming elements arranged at predetermined intervals to entangle the fibers and simultaneously form the apertures. 12. The method for producing a surface material for an absorbent article according to claim 11, wherein the apertures are formed by distributing fibers through an element. (13) The surface layer is formed by interlacing the second fiber web with fibers by spraying a high-speed water jet from above the second fiber web overlaid on the surface layer; A method for producing a surface material for an absorbent article according to claim 11, in which fibers are entangled. (14) The surface layer uses heat-fusible fibers that melt at a temperature of 90 to 140°C as part or all of the hydrophobic fibers in the second fibrous web, and the second fibrous web is attached to the surface layer. 12. The method for producing a surface material for an absorbent article according to claim 11, wherein the surface material of an absorbent article is formed by fusing the fibers by processing them under the above temperature in a stacked state and simultaneously fusing the fibers to the surface layer. (15) The fibers of the first fiber web have a fineness of 0.2 to 2.
d, and the fibers of the second fiber web have a fineness of 0.
．． 7 to 15d, manufacturing a surface material for an absorbent article according to claim 11. (16) The surface layer and the back layer each have a density of 0.
．． 03g/cm^3 or more, density 0.01~0.2g
/cm^3 Claim 11
A method for producing a surface material for an absorbent article according to item 1, item 12, item 13, or item 14. (17) The method for producing a surface material for an absorbent article according to claim 12, wherein the pore-forming element is a protrusion provided on the support surface.