JPH04253857A - Unwoven cloth used as surface material of sanitary material - Google Patents

Abstract

PURPOSE:To improve bulkiness and water permeability without lowering softness by causing a spontaneous fusion between a web layer A with a specified METSUKE (weight per square meter) which has a circular section while being made of filament A with a specified fineness and a web layer B with a specified METSUKE which has a hollow section while being made of filament B with a specified fineness to join in a dotted fusing section. CONSTITUTION:Filament A has a circular section while the fineness thereof is 1-2 denier. The METSUKE of a web layer A made up of an integration of the filament A is 5-15g/m<2>. A web layer B8 is made up of filament B and with a hollow section, the fineness of the filament is 3-5 denier. The METSUKE of the web layer B is 5-15g/m<2>. The web 16 laminated with the web layer B8 and the web layer A15 is conveyed to an endless screen conveyor 7 to be introduced into a heat embossed roll 17. The web 16 is imparted with heat and a pressure by means of a heat embossed roll 17 to soften or melt the filaments A and B. Then, both the filaments are solidified to be fused themselves.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonwoven fabric that can be suitably used as a surface material for sanitary materials such as sanitary napkins and disposable diapers used for urination and defecation of infants, adults, and patients.

0002

[Prior Art] Conventionally, surface materials for sanitary materials include:
Various nonwoven fabrics are used. For example, Jikko Sho 59-
A spunbond nonwoven fabric described in Japanese Patent No. 9620 and the like is used. Spunbond nonwoven fabric is composed of long fibers, has relatively high strength, and is considered to be preferable as a surface material for sanitary materials.

However, spunbond nonwoven fabrics do not have the bulkiness, water permeability, and surface properties (
It has been difficult to provide properties such as texture) and flexibility. This is due to the following reasons. That is, in order to provide bulkiness and water permeability to a spunbond nonwoven fabric, long fibers with a large fineness, that is, a large fiber diameter must be used as the constituent fibers. When long fibers with a large fiber diameter are accumulated, the gap between the long fibers becomes large, and bulkiness and water permeability are improved. However, since long fibers with a large fiber diameter have high rigidity, properties such as surface properties and flexibility of the spunbond nonwoven fabric deteriorate. In addition, in order to impart surface properties and flexibility to the spunbond nonwoven fabric, long fibers with a small fineness, that is, a small fiber diameter must be used as the constituent fibers. Long fibers with a small fiber diameter have low rigidity, and the spunbond nonwoven fabric obtained by accumulating them has excellent surface properties and is highly flexible.However, when long fibers with a small fiber diameter are accumulated, the gaps between the long fibers are This results in a decrease in bulk and water permeability.

0004

[Problem to be solved by the invention] From the above,
In order to give spunbond nonwoven fabrics the characteristics required for surface materials of sanitary materials, such as bulkiness, water permeability, surface properties, and flexibility, the following ideas can be considered. That is, the spunbond nonwoven fabric has a two-layer structure, with the upper layer being a web made of long fibers with a small fineness, and the lower layer being a web made of long fibers having a large fineness. However, even in this case, it was difficult to impart flexibility to the spunbond nonwoven fabric. This is because long fibers with high fineness and high rigidity are used in the lower layer. If long fibers with a fineness that does not reduce flexibility are used as constituent fibers of the lower layer, bulkiness and water permeability will decrease.

Therefore, the present invention uses long fibers that have a relatively small fineness but a large diameter as the long fibers constituting the lower layer of the spunbond nonwoven fabric, thereby improving bulk and water permeability without reducing flexibility. By improving
The present invention aims to provide a nonwoven fabric that can be suitably used as a surface material for sanitary materials.

[0006]

[Means for Solving the Problems] That is, the present invention has a web layer A having a circular cross section and a fabric weight of 5 to 15 g/m2 made of long fibers A having a fineness of 1 to 2 deniers, and a web layer A having a hollow cross section and having a basis weight of 5 to 15 g/m2. Fabric weight 5~ made up of long fiber B with fineness 3~5 denier
15 g/m2 of web layer B are laminated, and web layer A and web layer B are bonded in point-like fused areas where long fibers A and long fibers B are self-fused. The present invention relates to a nonwoven fabric used as a surface material for sanitary materials.

The nonwoven fabric according to the present invention has a two-layer structure, consisting of a web layer A and a web layer B.

[0008] The web layer A is composed of long fibers A. The long fibers A have a circular cross section and a fineness of 1 to 2 deniers. The long fibers A have a circular cross section in the web layer A.
This is to prevent the texture, that is, surface properties, of the material from deteriorating. If the long fibers A have a triangular or square cross section, the surface properties of the web layer A will deteriorate, which is not preferable. In addition, when the fineness of long fiber A becomes less than 1 denier, long fiber A
This is not preferable because the fiber diameter becomes too small, the voids formed between the long fibers A become small, and the water permeability decreases. On the other hand, if the fineness of the long fibers A exceeds 2 deniers, the surface of the web layer A will become rough and the surface properties will deteriorate, which is not preferable.

[0009] The web layer A made up of the long fibers A has a basis weight of 5 to 15 g/m2. The basis weight of web layer A is 5
If it is less than g/m2, the roughness of the surface of web layer B will extend to the surface of web layer A, resulting in a decrease in surface properties, which is not preferable. On the other hand, if the basis weight of the web layer A exceeds 15 g/m2, the voids formed between the long fibers A tend to become smaller, resulting in a decrease in water permeability, which is not preferable.

[0010] The web layer B is composed of long fibers B. The long fibers B have a hollow cross section. The hollow here is
As shown in FIG. 2, the long fibers B have one hollow in the cross section, and as shown in FIG.
In Fig. 3, there are also four hollow holes. Further, the cross-sectional shape of the long fibers B can be any shape such as circular, elliptical, triangular, or quadrangular. Long fiber B
The fineness is 3 to 5 deniers. Since the long fiber B has a hollow cross section, the fiber diameter is larger than that of a general solid long fiber even if the fiber diameter is the same. In other words, the fiber diameter is approximately twice as large as that of solid long fibers with the same fineness. This is because the hollow portion is also included in part of the fiber diameter. Furthermore, since the cross section is hollow, the rigidity is lower than that of solid long fibers of similar fineness. That is, the rigidity is reduced due to the elasticity due to the voids inside the long fibers B and the ease of bending due to the thinness of the thick portion. If the fineness of the long fibers B is less than 3 deniers, the fiber diameter will not be sufficiently large and bulkiness and water permeability will decrease, which is not preferable. On the other hand, if the fiber diameter of the long fibers B exceeds 5 deniers, the thick portion becomes relatively thick, resulting in a decrease in flexibility, which is not preferable.

[0011] The basis weight of the web layer B formed by accumulating the long fibers B is 5 to 15 g/m2. The basis weight of web layer B is 5
If it is less than g/m2, the strength of the web layer B becomes unsuitable for practical use, which is not preferable. On the other hand, if the basis weight of the web layer B exceeds 15 g/m2, the rigidity of the web layer B will increase and the flexibility will decrease, which is not preferable.

[0012] As the raw material for the long fibers A and B, any synthetic resin can be used, but it is particularly preferable to use a polyolefin resin such as polypropylene or polyethylene. This is because it is relatively inexpensive and has a light specific gravity, making it suitable as a surface material for disposable diapers and the like. Moreover, web layer A and web layer B have a basis weight of 5 to 15.
Although it can be used arbitrarily within the range of g/m2, it is particularly preferable that the ratio of the basis weight of both is 25-75:25-75.

[0013] Web layer A and web layer B are joined at the fused area. In the fused area, long fibers A and long fibers B are self-fused. Self-fusion means that the long fibers A and/or the long fibers B are bonded together by melting and solidifying. In addition, the fused area is
It is formed in the form of dots. Since the fused area is in the form of a film, a linear or flat fused area other than dotted areas is not preferable because the flexibility of the nonwoven fabric will decrease. Such dot-like fused areas can be created, for example, by laminating web layer A and web layer B and then passing them between embossing rolls heated to a temperature at which long fibers A and/or long fibers B soften or melt. It can be provided by

An example of the method for producing a nonwoven fabric according to the present invention is as follows:
The following is an explanation based on the apparatus shown in FIG.

First, a polyolefin resin is melt-spun from a rectangular spinneret 1 equipped with a large number of annular spinning holes. The melt-spun curtain-shaped long fibers B group 2 are cooled by a cooling air supply device 3 installed at a position below the spinneret 1. Along with this cooling, the long fiber group B 2 is pulled and stretched by a high-speed airflow pulling device 4 such as a rectangular air sucker. The long fibers B thus obtained have a hollow cross section. and,
The long fiber group B 2 that passed through the high-speed airflow traction device 4 and ejected from its outlet is opened by the reflectors 5 and 6,
The web layer B8 is accumulated on the endless wire mesh conveyor 7 to form a web layer B8.

Next, the polyolefin resin is melt-spun from a rectangular spinneret 9 equipped with a large number of circular spinning holes. The melt-spun curtain-shaped long fibers A group 10 are fed to a cooling air supply device 11 installed at a position below the spinneret 9.
cooled by Along with this cooling, the long fiber group A 10 is transferred to a high-speed airflow traction device 1 such as a rectangular air sucker.
2 and stretched. The long fiber A thus obtained has a solid circular cross section. The long fibers A group 10 passed through the high-speed airflow traction device 12 and ejected from its outlet are opened by the reflection plates 13 and 14, and accumulated on the web layer B8 to form the web layer A15. .

The web 16 in which the web layer B8 and the web layer A15 are laminated is conveyed by an endless wire mesh conveyor 7 and introduced into a hot embossing roll 17. Then, heat and pressure are applied to the web 16 by a hot embossing roll 17, and the long fibers A and B are softened or melted, and then solidified, so that both long fibers are self-fused. The self-fusing areas are provided in dots corresponding to the convex portions of the embossing roll 17, and bond the web layer B8 and the web layer A15. The nonwoven fabric 18 obtained as described above is then wound up by a winding machine 19.

[0018]

EXAMPLES Various types of nonwoven fabrics were obtained using the apparatus shown in FIG. 1 and the methods described below.

Examples 1 to 12 After heating and melting polypropylene resin (MFR=40) at 230°C and extruding it with an extruder, the length was 1200 mm.
Long fiber group B was spun using a rectangular spinneret (for hollow) with a width of 70 mm. This rectangular spinneret (for hollow) has 170 spinning holes arranged in the length direction and 5 in the width direction for spinning long fibers with a hollow cross section. Therefore, it has a total of 850 spinning holes. In Examples 1 to 6, the shape of the spinning hole was an annular hole with a connecting hole in the center, and in Examples 7 to 12, it had a triangular slit hole. It was used. Therefore, the cross section of the long fibers B obtained in Examples 1 to 6 is an ellipse with two hollow parts (indicated as hollow ellipse in Table 1), and the cross section of the long fibers B obtained in Examples 1 to 6 is elliptical (indicated as hollow ellipse in Table 1). The cross section of the long fiber B obtained in the above is triangular (indicated as a hollow triangle in Table 1) with one hollow part. The long fibers B group obtained as described above were stretched by being pulled using a rectangular high-speed airflow traction device, and then the long fibers B group were collided with a reflector to open the fibers. Next, long fiber group B was accumulated on an endless wire mesh conveyor equipped with a suction device on the back side to form web layer B. The fineness (denier) of the long fibers B constituting the web layer B was varied as shown in Table 1.
The basis weight of web layer B was 12 g/m2.

[0020] On this web layer B, a web layer A was formed in the same manner as described above, except that a medium-sized rectangular spinneret was used. i.e. rectangular spinneret (medium practical)
, 170 circular spinning holes were arranged in the length direction and 10 in the width direction, and using this, web layer A was formed on web layer B in the same manner as above. . Therefore, the cross section of the long fiber A obtained using this rectangular spinneret (medium practical) is simply circular (indicated as solid circular in Table 1). Further, various fineness (denier) of the long fibers A constituting the web layer A were prepared as shown in Table 1, and the basis weight of the web layer A was 11 g/m2.

The web in which web layer B and web layer A were laminated was conveyed by an endless wire mesh conveyor and introduced into a hot embossing roll. This hot embossing roll softens or melts both long fibers constituting each web layer, and then solidifies them, thereby bonding both long fibers to form dotted heat-fused areas, and forming web layer B and web layer A and A were combined to obtain a nonwoven fabric. The composition of each web layer of these nonwoven fabrics is shown in Table 1.
As shown below.

[0022]

[Table 1]

Comparative Examples 1 to 8 Similar to the above examples, web layers A and B shown in Table 2 were prepared by combining a rectangular spinneret (for hollow use) and a rectangular spinneret (for medium use). A nonwoven fabric was produced. The difference from the Examples is that the fineness of the long fibers B constituting the web layer B is outside the scope of the present invention.

Comparative Examples 9 to 12 Using only the rectangular spinneret (for hollow) used in the above examples, the web layer A shown in Table 2 was prepared.
And web layer B was created to produce a nonwoven fabric.

Comparative Examples 13 and 14 Using only the rectangular spinnerets (medium practical) used in the above examples, web layers A and B shown in Table 2 were prepared to produce nonwoven fabrics.

[0026]

[Table 2]

[0027] Above Examples 1 to 12 and Comparative Examples 1 to 14
The bulkiness, water permeability, surface properties, and flexibility of the nonwoven fabrics obtained were measured and evaluated, and the results are shown in Tables 3 and 4. In addition, evaluation of bulkiness etc. was based on the following test method. [Bulkiness] Tested by sensory test based on touch, and evaluated on the following four scales. ◎…Very good. ○…Good. △...Slightly bad. ×...Bad. [Water permeability] The nonwoven fabrics according to the examples and comparative examples were immersed in a surfactant solution (surfactant: manufactured by Sanyo Chemical Industries, Ltd., trade name Sunsilicone M-84, concentration: 0.3% by weight),
A sample was prepared by dehydration and drying. This sample was added to the web layer A.
Place the sample on the water absorbent sheet so that the web layer B is on the upper side and in contact with the water absorbent sheet.
ml was dropped, and the time (seconds) until the artificial urine was completely absorbed by the water absorbent sheet was measured. [Surface Properties] Tested by sensory test based on touch, and evaluated on the following four scales. ◎…Very good. ○…Good. △...Slightly bad. ×...Bad. [Flexibility] It was tested by a sensory test based on touch, and evaluated in the following four stages. ◎…Very good. ○…Good. △...Slightly bad. ×...Bad.

[0028]

[Table 3]

[0029]

[Table 4]

As is clear from the above results, the nonwoven fabric according to the example has a good balance of bulkiness, water permeability, surface properties, and flexibility, and is suitable for each characteristic as a surface material for sanitary materials. . On the other hand, in Comparative Examples 1 to 8, the long fibers B with a small fineness were inferior in bulk and had insufficient water permeability, and the long fibers B with a large fineness were poor in flexibility. In Comparative Examples 9 to 12, the surface properties were poor. Moreover, in Comparative Examples 13 and 14, the bulkiness was poor and the water permeability was also low.

[0031]

[Operation and Effects of the Invention] As explained above, the nonwoven fabric according to the present invention is composed of a web layer A having a basis weight of 5 to 15 g/m2 and a web layer B having a basis weight of 5 to 15 g/m2,
Web layer A and web layer B are joined by point-like fused areas. Since the web layer A has a circular cross section and is composed of long fibers A having a fineness of 1 to 2 deniers, it imparts good surface properties and flexibility to the nonwoven fabric. Further, since the web layer B is composed of long fibers B having a hollow cross section, the fiber diameter is thick compared to the fineness (3 to 5 deniers). Therefore, the web layer B has high bulkiness, and the gaps formed between the long fibers B are also large, so that the web layer B has good water permeability. Therefore, the nonwoven fabric according to the present invention has the effect of easily having the characteristics of good bulkiness, water permeability, surface property, and flexibility, which were difficult to have in conventional nonwoven fabrics. Such a nonwoven fabric according to the present invention can be suitably used as a surface material for sanitary materials such as sanitary napkins and disposable diapers, with the web layer A on the outside and the web layer B on the inside.

Although the nonwoven fabric according to the present invention is mainly used as a surface material for sanitary materials, the nonwoven fabric according to the present invention can also be used for other purposes.
Of course, it can also be used as a material for clothing, a wiping cloth, etc.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of an apparatus for manufacturing a nonwoven fabric according to the present invention.

FIG. 2 is a sectional view showing an example of the cross section of long fiber B used in the present invention.

FIG. 3 is a sectional view showing an example of the cross section of long fiber B used in the present invention.

[Explanation of symbols]

2 Long fiber group B 8 Web layer B 10 Long fiber group A 15 Web layer A 18 Non-woven fabric

Claims (1)

[Claims] Claim 1: A web layer A having a fabric weight of 5 to 15 g/m2, which is composed of long fibers A having a circular cross section and a fineness of 1 to 2 deniers, and a web layer B having a hollow cross section and having a fineness of 3 to 5 deniers. The constructed web layer B having a basis weight of 5 to 15 g/m2 is laminated, and the web layer A and the web layer B are formed by dot-like fusion formed by self-fusion of long fibers A and long fibers B. A nonwoven fabric used as a surface material for sanitary materials, characterized in that it is bonded in the wearing area.