JPH0118180B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a nonwoven fabric using absorbent cotton strips as a raw material.

Conventionally, nonwoven fabrics of this type have been made of synthetic fibers such as rayon, pulverized pulp with a binder added thereto, and rayon or pulverized pulp processed by pressing, or those obtained by pressing without adding a binder.

However, since nonwoven fabrics are commercialized as sanitary products and diapers and then delivered to consumers, they often come into direct contact with the human body during use.
The safety of synthetic fibers and binders has become a problem, and in recent years, nonwoven fabrics made of natural fibers, mainly cotton, have been provided with safety in mind.

In order to process the above-mentioned cotton into a non-woven fabric, methods have been proposed, such as compressing and embossing an absorbent cotton band into a flat cloth using embossing means, or adding a heating process. Absorbent cotton strips are press-processed with the fibers in a uniform state, so the fibers are not sufficiently entangled with each other, and there is often a risk that the compressed state will loosen and the nonwoven fabric will expand before the nonwoven fabric is used. As a result, when processed into the sanitary products and diapers mentioned above, it may be difficult to process and the water absorption performance may deteriorate.

The present invention aims to provide a nonwoven fabric that solves the above problems.

The method of the present invention will be explained below with reference to the accompanying drawings. Figure 1 is a schematic illustration showing the method of the present invention, in which 1 indicates a water needling step, 2 an embossing step, 3 a dehydration step, and an absorbent cotton band. 4
is a flat nonwoven fabric 5 whose fibers are entangled with each other by a waterjet means when passing through the water needling process 1, and then press-processed by passing through the embossing process 2. be done.

The absorbent cotton band 4 as the raw material may be made of pure cotton, but it is also possible to use a blended cotton in which waste cotton or staple fibers are mixed, and if the latter is used, the cost can be reduced.

Before being sent to the water needling step 1, the absorbent cotton band 4 has a uniform shape with a low degree of intertwining of the fibers, so if it is pressed in the embossing step 2 as it is, the product is The entanglement between the fibers of the nonwoven fabric may be insufficient.

Therefore, in the method of the present invention, after the water needling step 1 is performed to sufficiently entangle the fibers of the absorbent cotton band 4, the embossing step 2 is performed.
A flat nonwoven fabric 5 is manufactured in this manner.

The water needling step 1 has a configuration in which a water jet means, for example, a water injection device 11 is installed above the feed path W of the absorbent cotton band 4, and the water injection device 11 generates a jet flow of water, that is, jet water. By jetting and penetrating the absorbent cotton band 4 in the thickness direction with jet water, the absorbent cotton band 4 is sequentially streaked with needling portions 4' along the longitudinal direction as shown in FIGS. 3 and 4. All such structures are known.

In the embodiment, the water injection device 1 has a feeding space 11 for absorbent cotton band 4 between it and the feeding path W, as shown in FIG.
1, the absorbent cotton band 4 is provided above the feeding path W and moves in the feeding space 111.
The structure has a large number of minute nozzles 112 that inject water at a predetermined pressure into the nozzle 112.
are arranged in one row in a direction perpendicular to the feeding path W.

It is desirable that the configuration of the nozzle 112 can be changed depending on the thickness and fiber density of the absorbent cotton strip 4 as the raw material, but normally the nozzle 1
When 12 is formed into a circular shape, the diameter should be 0.13 mm, the interval between each nozzle should be set to 1 mm, and the water pressure of the jet water should be about 30 kg.

When the absorbent cotton strip 4 is water needled with the above-mentioned jet water, the absorbent cotton strip 4 has fiber needling portions 4' in parallel along its longitudinal direction, as shown in FIGS. 3 and 4. Because of this, the above water needling step 1
Compared to the absorbent cotton band 4 before passing through, the entanglement between the fibers is sufficient.

Note that the water injection device 11 can be operated by reciprocating the water injection device 11 from side to side in FIG. 2 without fixing its nozzle 112, so that the needling portion 4' can be fixed as seen from above, as shown in FIG. Alternatively, the nozzle 112 may be formed into a long hole, and the water jet may be stopped instantaneously to perform water needling on the absorbent cotton band 4 intermittently. ', the sixth
As shown in the figure, it is also possible to configure the absorbent cotton band 4 to be formed in a parallel shape orthogonal to the longitudinal direction of the absorbent cotton band 4.

The water needling step 1 improves the intertwining state between the fibers of the absorbent cotton strip 4, but at the same time causes the absorbent cotton strip 4 to absorb water, so it is necessary to dry the absorbent cotton strip 4 before it reaches the embossing step 2. Therefore, after the water needling process, a dewatering process 3 such as a drying room is provided to dry the absorbent cotton band 4.

As shown in FIG. 1, the embossing process 2 has a pair of upper and lower pressing rollers 21, 22, and one or both of these pressing rollers 21, 22 is configured as an embossing roller.

The pressure rollers 21 and 22 are approximately 5 kg/cm ² to 40 kg/cm ² during the pressing process, preferably 20 kg/cm 2 to 40 kg/cm 2 .
It is sufficient to set the pressure to apply a pressure of Kg/cm ² to 30 Kg/cm ² .In this case, if the upper roller 21 is constructed as an embossing roller having a large number of dot-shaped protrusions, as shown in FIG. As shown in FIGS. 8 and 9, it is possible to manufacture a nonwoven fabric 5 having a large number of minute dot-shaped recesses 51 on only one side, and in which the recesses 51 are separated by protrusions 52.

Furthermore, if the lower roller 22 as well as the upper roller 21 is constructed as an embossing roller, it is possible to produce a nonwoven fabric 5 having a large number of dotted recesses 51 on both sides of the nonwoven fabric 5, as shown in FIG.

The size of the point-shaped recess 51 is usually a pinpoint recess with a diameter of about 0.3 mm, a polygonal recess,
For example, the tortoiseshell-shaped recess has a diameter of about 0.5 mm, but the size of the recess can be freely selected depending on the purpose of use of the nonwoven fabric 5 and other conditions, and can be selected between approximately 0.1 mm and 2 mm.

Furthermore, the protrusions of the embossing roller can be formed linearly, and in this case, the recesses 51' are formed into fine linear recesses, and the protrusions 52' are formed into dotted protrusions, as shown in FIG. It is formed.

Normally, when one of the pressure rollers 21 and 22 is used as an embossing roller, a steel roller is used as the other in order to maintain the pressing force. It is desirable that the rollers other than the rollers be paper rollers, and in this way the embossing projections can be passed through the absorbent cotton strip 4 to produce a mesh-like nonwoven fabric 5.

On the other hand, the pressure rollers 21, 22 are constructed of steel rollers, and the rollers are provided with heating means to heat the pressure rollers 21, 22 to a temperature of, for example, 30°C to 180°C, preferably 80°C to 120°C.
The nonwoven fabric 5 may be ironed by heating, and this method has a great effect of preventing expansion of the nonwoven fabric 5.

The nonwoven fabric 5 pressed in the embossing process 2 has a thickness of 1/3 to 1/8 compared to the raw material absorbent cotton strip 4, so it is extremely convenient for packaging, transportation, and storage. 4 has the property of shrinking when water is absorbed, whereas the nonwoven fabric 5 usually has a small volume and has a property of expanding when water is absorbed.

Furthermore, since the fibers of the nonwoven fabric 5 are tightly intertwined in the concave portions 51 and 51', when the nonwoven fabric 5 absorbs water, the protrusions 52 and 52' swell first.
Since it is thought that water percolates from the swollen protrusions 52, 52' into the recesses 51, 51' by capillary action, the water absorption performance is also good.

Since the method of the present invention is as described above, the following effects can be expected.

Since the fibers are sufficiently entangled over the entire surface of the absorbent cotton strip 4 in the water needling step 1, compared to the case where the absorbent cotton strip 4 is directly fed into the embossing step 2, the inter-fiber entanglement is It is possible to produce a nonwoven fabric 5 that is tightly entangled, and can therefore maintain the pressed state for a long time in the embossing process 2. Furthermore, since the density between the fibers is high, it has good water absorption and air absorption performance. There is also this effect.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram illustrating the method of the present invention, Fig. 2 is a front view showing a water injection device as a water jet means used in the water needling step of the method of the present invention, and Fig. 3 is the water needling step of the same method. Fig. 4 is a cross-sectional view of the above absorbent cotton band, Fig. 5 is a plan view showing another embodiment of the above absorbent cotton band, and Fig. 6 is a further embodiment of the above absorbent cotton band. FIG. 7 is a plan view showing an example, and FIG. 8 is a cross-sectional view of a nonwoven fabric produced by the method of the present invention.
9 are perspective views showing a part of the same nonwoven fabric, FIG. 10 is a sectional view showing another example of the same nonwoven fabric, and FIG. 11 shows a part of yet another example of the same nonwoven fabric. FIG. In the figure, 1 is a water needling process, 11 is a water injection device as a water jet means, 2 is an embossing process, 21 and 22 are pressure rollers,
3 is a dehydration process, 4 is an absorbent cotton band, 4' is a needling part, 5 is a nonwoven fabric, 51, 51' is a recessed part, 52,
Reference numerals 52' indicate protrusions.

Claims (1)

[Claims] 1. A water needling step in which the fibers of the absorbent cotton strip are intertwined with each other by water needling the absorbent cotton strip with a waterjet means, and a dehydration step in which the absorbent cotton strip is dried after this water needling step. After this dewatering process, the absorbent cotton strip is pressed flat by a pair of upper and lower pressing rollers, and at least one of the pressing rollers is provided with dot-like or linear protrusions, so that minute dots are formed on the absorbent cotton strip. or an embossing process of forming a large number of fine linear recesses.