JPH0814060B2 - Open-hole nonwoven fabric and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the Invention [Field of Industrial Application] The present invention relates to an apertured nonwoven fabric having a large number of apertures of different sizes and shapes irregularly, and a method for producing the same.

INDUSTRIAL APPLICABILITY The non-woven fabric according to the present invention can be widely used for sanitary and cosmetic materials such as bandages, gauze and puffs, core materials such as clothing and footwear, dust cloths, heat insulating materials, and electrical insulating materials.

[Prior Art] Conventionally, there is known a non-woven fabric having substantially the same size and shape of openings and having a pattern in which the openings are regularly arranged. Such a non-woven fabric is generally a mesh screen in which the knuckle portions where the constituent wire rods intersect are regularly arranged, and the fibers are rearranged by injecting a high-speed water stream toward the fiber material layer guided on the support, It is manufactured by forming a large number of openings corresponding to the knuckle portion.

On the other hand, there is also known a nonwoven fabric having substantially the same shape of openings and having a pattern in which large openings and small openings are regularly arranged. Such a non-woven fabric has a drum, in which the openings are regularly arranged, and a mesh screen as described above, which is arranged with a gap on the outer periphery of the drum, as a support, and is directed toward the fiber material layer led to the gap. A high-speed water stream is jetted from the inside to rearrange the fibers, and a large number of large holes corresponding to the holes of the drum and a large number of large holes corresponding to the knuckle portion of the screen are formed in the fiber collecting area between the large holes. Manufactured by forming small apertures.

[Problems to be Solved by the Invention] As described above, in the former nonwoven fabric, the apertures having substantially the same size and shape are regularly arranged,
The latter non-woven fabrics have substantially the same shape but have regularly arranged apertures of two different sizes, and generally these apertures are circular or elliptical. . Therefore, such a non-woven fabric is relatively aesthetically pleasing and suitable for certain types of applications, while it has a regular array of apertures and a uniform size and shape, so it is not suitable for certain types of applications. Not suitable. For example, a bandage is usually used overlapping a wound, etc., and depending on the size of the opening, it depends on the size of the opening. It may leak and fail to function as a bandage. Therefore, although it may not be said that it is aesthetically pleasing depending on such a certain kind of use, it is rather preferable that the openings have a random arrangement and a wide variety of sizes and shapes. There is.

Further, the former and latter manufacturing methods cannot manufacture a preferable nonwoven fabric in this sense. As well,
Since a mesh screen is used as a support for the fibrous material layer, the fibers are entangled in the knuckle portion of the screen in the treatment of the fibrous material layer with a high-speed water flow, so that when the fibrous material layer is peeled from the screen after the treatment, the fibers are entangled. Fiber breaks. Therefore, frequent replacement of the screen is unavoidable, which is uneconomical, and the finished non-woven fabric has a relatively large amount of fuzz, and
The pulling at the time of peeling may disturb the fiber arrangement and the entangled state, leading to a decrease in strength. Furthermore, because of the structure of the screen, the jet water flow still having the treatment energy passes through the screen. In other words, in the screen, there is almost no repulsive flow of the jet water flow generated by collision with the screen, and Since it cannot be fully utilized as processing energy, processing efficiency is also low.

The first aspect of the present invention is to provide an apertured nonwoven fabric which is suitable for a certain kind of use as described above, in which the apertures are randomly arranged, and the size and shape of which are rich in variety.

A second aspect of the present invention is to provide a method for producing an apertured non-woven fabric, which allows the non-woven fabric to be mass-produced at low cost with high treatment efficiency, has relatively few fluffs, and does not cause strength reduction.

(2) Configuration of the Invention [Means for Solving the Problems] The first aspect of the present invention is a non-woven fabric which maintains a sheet-like form by fiber entanglement and has a large number of apertures divided by fiber gathering regions. And is characterized by the following points.

The openings are roughly classified into two kinds, large ones and small ones, the large ones are smaller than the small ones and are irregularly scattered among the small ones, and the large openings are: The individual area is 1.5 to the individual area of the small aperture.
3 times and the total area is 30% or less of the total area of the small openings.

The second aspect of the present invention is a rearrangement treatment of fibers by a jet water flow on a support having a structure for forming a large number of holes in which a fiber material layer in which fibers can move under the influence of a jet water flow is regularly arranged. The method for producing an open-pore non-woven fabric according to claim 1, wherein a large number of pores are formed, characterized by including the following steps.

a. A step of forming a large opening corresponding to the structure by performing the treatment on the first support having a structure for forming a relatively large opening.

b. After the step, by performing the treatment on the second support having a structure for forming a relatively small opening, a small hole corresponding to the structure is formed into a fiber assembly in which the large opening does not exist. Forming the region, and at the same time, dividing the large opening into a plurality of small openings having various shapes by crossing and spanning the large opening in multiple directions.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.
However, for convenience of description, the first and second inventions will be described together.

Referring to FIG. 1, a fibrous material layer 1 is attached to a first support 2
After the fibers are rearranged by a jet water flow from a plurality of nozzles 3 arranged at required intervals on the required peripheral area of the support, a plurality of fibers arranged in the required area of the support in the longitudinal direction are arranged. The fibers are further rearranged by the jet of water from the nozzle 5.
During these treatments, the water flow that has finished working on the fibrous material layer 1 is forcibly discharged by the suctions 6 and 7 arranged below the first and second supports 1 and 2, respectively. Although not shown, the fibrous material layer 1 after the treatment is passed through the squeezing roll 8 and
Transfer to the next drying step and winding step.

As shown in FIG. 2 and FIG. 3, the first support body 2 includes a large number of projections 9 and drain holes at required intervals on the circumferential surface of the cinder.
It is preferable to use those in which 10 and 10 are regularly arranged. With this first support 2, the fibers of the fibrous material layer 1 located on the projections 9 are rearranged under the influence of the jet of water while being distributed in the plane area between the projections. Therefore, regular openings corresponding to the arrangement of the protrusions 9 are formed in the fiber material layer 1. This rearrangement also means that when the fibers of the fiber material layer 1 are not sufficiently entangled, the fibers are entangled to give a sheet-like form. The fibrous material layer 1 may be a non-woven fabric that has already been formed, or may be a loosely aggregated fiber, such as a card web, as long as the fibers can move under the influence of the jet water flow. ,
The latter is preferable for economically obtaining the nonwoven fabric of the present invention. However, in the latter case, the fibers are loosely aggregated and fluffing is large and the morphology is unstable. Therefore, during processing, as shown in FIG. 1, a water film is supplied from the tank 11 to the fiber material layer 1 to stabilize the morphology. Preferably.

With the first support 2 shown in FIGS. 1 and 2, since it has a plate-shaped flat area between the projections 9, the fibers impinge on the jet water stream impinging on it and the flat area. It is processed by both energy of repulsive flow generated as a result. Therefore, the treatment efficiency and the entanglement strength are extremely high, and further, the fibers are entangled with the surface of the support, and after the fiber material layer 1 is processed, the rearranged state and the entangled state of the fibers are disturbed when the fibers are separated from the support. Never.

As the second support 4, it is possible to use a mesh screen having a large number of knuckle portions where constituent wires intersect with each other. When the second support 4 is used, the fibers of the fiber material layer 1 located on the knuckle portion are rearranged while being distributed to the mesh (mesh) between the knuckle portions under the influence of the jet water flow.

This second support 4 has a knuckle portion which is considerably smaller than the protrusion 9 of the first support 2. Therefore,
In the fiber assembly region where the openings are not formed by the treatment with the first support 2, openings smaller than the openings are formed corresponding to the arrangement of the knuckle portions of the second support 4. . at the same time,
Most of the large apertures already formed corresponding to the arrangement of the protrusions 9 of the first support 2 are spanned by fibers in multiple directions therein. As a result, the majority of the large apertures are divided into multiple small apertures.

The mesh screen as the second support 4 has a projection 9
As compared with the first support 2 having the above condition, the repulsive flow of the jet water hardly occurs, so that the repulsive flow can hardly be used for rearrangement of the fibers. However, the treatment with the second support 4 is performed after finishing the treatment with the first support 2, and the shape of the fiber material layer 1 is already stabilized during the former treatment. Therefore, it does not matter if a mesh screen is used for the former treatment. Moreover, the fact that the rearrangement of fibers on the second support may also mean fiber entanglement is the same as that on the first support.

As the constituent fibers of the fibrous material layer 1, those conventionally used as that of a non-woven fabric or a woven fabric are used, and
Generally, the fiber length and denier are 20-100m, respectively.
m, 0.5-15d is used. Further, the basis weight of the fiber material layer 1 is generally 10 to 150 g / m ² .

The jet water flow is a fine columnar flow with a pressure of 15 kg / cm ²
The above is also used.

The perforated nonwoven fabric obtained by such a manufacturing method maintains a sheet state by fiber entanglement and has a large number of perforations divided by the fiber aggregation region. These openings have various sizes and shapes and are mixed irregularly and are rich in variety, and when roughly classified, they include two kinds, large ones and small ones. The larger openings are smaller in number than the smaller openings and are randomly interspersed between the smaller openings. The large aperture is
It is preferred that the individual areas are 1.5 to 3 times the individual areas of the small openings and the total area is 30% or less of the total area of the small openings.

Example 1 A card web of rayon fibers of 1.5 d X 44 mm and 30 g / m ² was introduced into the apparatus shown in FIG. 1 and sucked and drained from the lower side of the first support 2 shown in FIG. , Back pressure 70kg / cm ²
By injecting the columnar flow of the above at 1.3 / m ² , as shown in FIG. 4, a perforated nonwoven fabric in which large perforations corresponding to the projections of the support were regularly arranged was obtained.

Further, the open-pore non-woven fabric was suctioned and drained from the lower side on a 15-mesh plain polyester monofilament screen serving as the second support 4, and a back pressure 70
By injecting a columnar flow of kg / cm ² at 4 / m ² ,
As shown in the figure, at the same time the small openings corresponding to the knuckle portion of the screen are arranged in the fiber assembly region where the large openings do not exist, and at the same time, the large openings are divided into small openings by fibers. I got it.

Example 2 The conditions were the same as in Example 1 except that the second mesh screen was 18 mesh. As a result, as shown in FIG. 6, a perforated nonwoven fabric substantially similar to the perforated nonwoven fabric of Example 1 was obtained.

Example 3 The amount of water sprayed on the first support 2 was 5 / m ² , and
The conditions were the same as in Example 1 except that the mesh screen was 15 mesh. As a result, as shown in FIG.
An open-hole nonwoven fabric similar to the open-hole nonwoven fabric of Example 1 was obtained.

Comparative Example 1 As shown in FIG. 8, the columnar flow was injected at 4 / m ² on the second support without using the first support 2 in the apparatus shown in FIG. A non-woven fabric having substantially the same size and shape and having the apertures regularly arranged corresponding to the knuckle portion of the screen was obtained. The other conditions were the same as in Example 1. Comparative Example 2 The conditions were the same as in Comparative Example 1 except that the mesh screen as the second support 4 was 18 mesh. As a result, as shown in FIG. 9, a perforated nonwoven fabric substantially similar to the perforated nonwoven fabric of Comparative Example 1 was obtained.

(3) Effects of the Invention According to the open-pore nonwoven fabric of the first aspect of the present invention, the open-pores have various sizes and shapes and are irregularly mixed, which is rich in variety. In addition, it is possible to widely and suitably use for an unsuitable application in an open-pore nonwoven fabric in which the sizes and shapes of the openings are substantially the same and which are regularly arranged.

In addition, according to the method for producing an apertured nonwoven fabric of the second aspect of the present invention, as described above, an apertured nonwoven fabric having a wide variety of apertures can be mass-produced easily with high treatment efficiency at low cost. Moreover, since the two-step treatment is performed in this way, even when a mesh screen is used for the second treatment, the fibers are entangled in the knuckle portion of the screen in the treatment, and therefore the treated non-woven fabric is peeled from the screen. At that time, there is no possibility of fluffing or disturbing the fiber arrangement or the entangled state to reduce the strength.

[Brief description of drawings]

FIG. 1 is a schematic side view of an apparatus for carrying out the method of the present invention. FIG. 2 is a perspective view of the first support disposed in the device. FIG. 3 is a partial cross-sectional view of a state where fibers are distributed by the protrusions of the first support. FIG. 4 is a plan view of the same magnification showing the structure of a nonwoven fabric in which large openings are formed in the first support. FIG. 5 to FIG. 7 are plan views of equal magnification showing the structures of the completed nonwoven fabrics of Examples 1 to 3 in which the small openings are formed by the second support. 8 and 9 are plan views at equal magnification showing the structures of the nonwoven fabrics of Comparative Examples 1 and 2. However, the fiber portion in FIGS. 4 to 9 is shown in white. 1: fibrous material layer, 2: first support 4: second support, 9: protrusion 10: drainage hole.

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Claims (3)

[Claims] 1. A non-woven fabric which maintains a sheet-like shape by fiber entanglement and has a large number of pores divided by a fiber gathering region, wherein the pores are roughly classified into two types, a large one and a small one. Wherein the larger ones are smaller than the smaller ones and scattered irregularly among the smaller ones, wherein the large apertures have an individual area of 1.5 to 3 times the individual area of the small apertures. And the total area is 30% or less of the total area of the small openings. 2. A rearrangement process of fibers by a jet of water is carried out on a support having a structure for forming a large number of holes in which a fiber material layer in which fibers can move under the influence of a jet of water is regularly arranged. The method for producing an open-pore nonwoven fabric according to claim 1, wherein the treatment includes the following steps. a. A step of forming a large opening corresponding to the structure by performing the treatment on the first support having a structure for forming a relatively large opening. b. After the step, by performing the treatment on the second support having a structure for forming a relatively small opening, a small hole corresponding to the structure is formed into a fiber assembly in which the large opening does not exist. Forming the region, and at the same time, dividing the large opening into a plurality of small openings having various shapes by crossing and spanning the large opening in multiple directions. 3. The method according to claim 2, wherein the first support is a cylinder having a hole-forming projection and a drainage hole, and the second support is a mesh screen. A method for producing an open-pore nonwoven fabric according to item.