JPH0140140B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing a nonwoven fabric using absorbent cotton strips as a raw material. (Prior Art) Conventionally, nonwoven fabrics have been provided that are pressed using pulverized pulp or synthetic fibers such as rayon, polyester, etc. However, when the pulverized pulp is used, a binder is used to bond the pulp together. In addition, the nonwoven fabrics mentioned above are often sold as products that come into direct contact with the human body, such as sanitary products and diapers, so the negative effects of the binders and synthetic fibers on the human body must be considered. I needed to. Therefore, in recent years, nonwoven fabrics made from natural fibers, mainly absorbent cotton obtained by defatting cotton, have been provided in order to eliminate the above-mentioned drawbacks. That is, the above-mentioned absorbent cotton band is pressed and compressed flat with a roller or the like to be processed into a cloth-like shape, or alternatively, in addition to being simply pressed and compressed, for example, an embossing method is simultaneously applied, or furthermore, ironing is added. In some cases. However, since the above-mentioned absorbent cotton is purified cotton, even if it is compressed, embossed, or ironed into non-woven fabric, it has the disadvantage that it easily expands. In some cases, it may not be able to take full advantage of its advantages as a nonwoven fabric, that is, it takes up less space to store and carry than absorbent cotton, and it also has the disadvantage that its water absorption and humidity performance deteriorates. . (Problems to be Solved by the Present Invention) The method of the present invention aims to provide a nonwoven fabric that eliminates the above-mentioned disadvantages. (Means for Solving the Problems) The method of the present invention will be explained below with reference to the accompanying drawings. Fig. 1 is a schematic explanatory diagram of the method of the present invention, in which 1 is an absorbent cotton band as a raw material, 2 is a steam injection Step 3 is an embossing step, and 4 is a nonwoven fabric. It is usually preferable to use pure cotton for the absorbent cotton band 1, but in some cases, it is also possible to use mixed cotton mixed with waste cotton, cotton wool, fibers, etc., which is advantageous in reducing manufacturing costs. becomes. Since the absorbent cotton strip 1 is purified as described above, the bonding state between each fiber cannot be said to be sufficient, and if the absorbent cotton strip 1 is pressed as it is in the embossing step 3, the embossed The nonwoven fabric sent out from the processing step 3 can be easily expanded as in the conventional case. Therefore, the method of the present invention provides the steam injection step 2 immediately before the embossing step 3,
By spraying steam onto the absorbent cotton band 1,
The absorbent cotton strip 1 is humidified and heated, and then sent to the embossing process 3. The steam injection step 2 is composed of a steam injection means, for example, a steam injection machine 21, which is disposed above the feeding path W of the absorbent cotton strip 1, as shown in FIG. It has a large number of minute nozzles 22 perpendicular to the feed path W, which ejects steam vertically over the entire width of the absorbent cotton band 1 moving on the upper surface of the path W, and further includes the steam injector 21 and the feed path W. A feeding space 23 for the absorbent cotton band 1 is provided between the two. The structure of the steam injector 21 is free; for example, it may be installed integrally with the feed path W instead of being provided above the feed path W, or the nozzle 22 may be a fine elongated hole. Therefore, in the steam injection step 21,
The absorbent cotton band 1 is humidified and heated to a temperature of 50 to 180°C in advance, and then sent to the embossing process 3. The embossing process 3 includes, for example, a pair of press rolls 3 provided above and below in a position where the humidifying and heating state of the absorbent cotton band 1 on the feeding path W is not lost.
1 and 32, and one or both of the pair of press rolls 31 and 32 is formed into an embossing roll. The pressure rolls 31 and 32 have a pressing force of 1000 to 20000 Kg/cm ² (1 to 20 tons/cm ² ) against the absorbent cotton strip 1.
One roll is the driven side, and the other is the driving side through a booster mechanism (not shown) using hydraulic or pneumatic pressure. Both axes are arranged in an intersecting relationship in the vertical direction so as not to cause non-uniform deflection of the core. As an example, the input pressure on the drive side is 6Kg/ ^cm2 , and the final output pressure (pressing force) is 1000 by the booster mechanism.
doubled to Kg/cm ² . In the present invention, 1 to 20 tons/
Embossing under high pressure of cm ² is a special feature that could not be applied to absorbent cotton strips up to now, and as will be clear from the examples below, this increases the tensile strength of cotton strips. In particular, the tensile strength in the longitudinal direction has been improved by a maximum of 52 times, the thickness has been reduced to less than 1/10 at the maximum, and both the amount and range of water absorption have been improved. In the above roll configuration, if the upper roll 31 is configured as an embossing roll having a large number of dot-like protrusions, it will have a large number of minute dot-like recesses 41 on only one side, as shown in FIGS. 3 to 5, and A nonwoven fabric 4 in which the recesses 41 are separated by the projections 42 can be manufactured. Furthermore, if the lower roll 32 as well as the upper roll 31 is constructed as an embossing roll, it is possible to produce a nonwoven fabric 4 having a large number of dot-shaped recesses 41 on both sides of the nonwoven fabric 4, as shown in FIG. The size of the point-shaped recess 41 is usually a pinpoint recess with a diameter of about 0.3 mm, a polygonal recess,
For example, it is a tortoiseshell-shaped recess with a diameter of about 0.5 mm, but the size of this recess 51 can be freely selected depending on the purpose of use of the nonwoven fabric 4 and other conditions, and is approximately 0.1 mm in diameter.
It is best to select between mm and 2 mm. Furthermore, the protrusions of the embossing roll can be formed linearly. In this case, for example, as shown in FIG. Formed on a protrusion. In this way, the absorbent cotton band 1 is humidified and heated in the steam injection step 2, and then processed into the nonwoven fabric 4 through the embossing step 3. In order to enhance the compression effect by embossing, the method of the present invention For example, steel rolls are used as the pressure rolls 31 and 32, and the steel rolls are provided with heating means if desired, so that the temperature is, for example, 30°C.
It may be configured such that the pressure rolls 31 and 32 are heated to a temperature of 80°C to 120°C, preferably 80°C to 120°C, thereby embossing the absorbent cotton band 1 while heating it. (Function) With the above configuration, the absorbent cotton band 1 is compressed by the pressure rolls 31 and 32 in addition to being humidified and heated by steam, so that it is subjected to so-called ironing and processed into a nonwoven fabric 4 that has a high compression effect, that is, does not easily expand. be done. In addition, when heating the pressure rolls 31 and 32, the heating temperature is set to a low temperature range within the above-mentioned appropriate temperature range, since the absorbent cotton band 1 has already been heated in the steam injection step 2. It is sufficient if the pressure rolls 31, 3 are
Although only one of the two may be heated, heating both pressure rolls as described above has the advantage of increasing the effect of ironing. Furthermore, when embossing the aforementioned pinpoint type recesses on the nonwoven fabric 4, one roll is used as an embossing roll, while the other roll has heat resistance,
In addition, it is preferable to use a roll made of a soft material such as paper, and in this way, the embossing projections are passed through the absorbent cotton band 1 to form a mesh-like nonwoven fabric 4.
can be manufactured. In the nonwoven fabric 4, since the fibers are tightly entangled in the recesses 41 and 41', the protrusions 42 and 42' in which the fibers are relatively loosely entangled during use,
It is thought that moisture and water are first absorbed, and water percolates from the protrusions 42, 42' into the recesses 41, 41' by capillary action, thereby enlarging the water absorption surface. (Example) Examples of cotton nonwoven fabrics obtained by the present invention are illustrated below along with comparative examples. For ease of understanding, samples with the same type and roll pressure are categorized and summarized in a table.

【table】

【table】

【table】

[Table] (Table 1) shows that the tensile temperature of the 100% absorbent cotton sample was 8% vertically by the method of the present invention.
It can be seen that the width has been improved by more than 3 times to more than 10 times, the thickness has been reduced to less than 1/10, and the size of the water absorption surface has expanded. . Sample No. 3 is generally the best. (Table 2), even in the case of blended cotton, the tensile strength is improved by over 12 times to approximately 15 times in the vertical direction, and over 22 times to 48 times in the horizontal direction, the thickness is less than 1/5, and the size of the water absorption surface is also improved by 5 times. It can be seen that it has expanded to about twice the size. (Table 3) shows that when a roll pressure of 1 ton/cm ² is applied, the tensile strength is increased by a little over 1 to 6 times in the vertical direction, and 6 to 8 times in the horizontal direction. This has a lower reinforcing effect than the high-pressure embossed ones shown in Tables 1 and 2. It can be seen that the thickness is less than 1/4. To further summarize the above, the effect of reinforcement improvement appears in the roll pressure range of 1 to 20 tons/cm ² , and the results are particularly remarkable in the range of 10 to 15 tons/cm ² . At 20 tons/cm ² or 10 tons/cm ² , there is a slight tendency to decrease compared to 10 to 15 tons/cm ² . (Effects of the Invention) The cotton nonwoven fabric obtained by the present invention is manufactured by being subjected to extremely high pressure of 1000 to 20000 Kg/cm ² and embossing under steam heating. As shown above, the tensile strength has been significantly improved, and the thickness has also been made sufficiently thin (maximum 1/10 or less), so the inherent advantages of nonwoven fabrics can be fully utilized, and they do not take up much space when stored or transported, and can be carried around roughly. It can withstand heavy handling and is thinner, so its volume before use is smaller, and since its substance is a cotton band, the amount of water absorbed per unit volume doubles (for example, if the thickness (If the amount of water is 1/5, the amount of water absorbed will be 5 times as much.) By expanding the water absorption surface, the water absorption performance has been greatly improved, and since it is a processed product of cotton belt, it feels good to the touch... There is a benefit. Also, from a manufacturing method point of view, it has the advantage that it can be carried out by adopting a steam injection means and an embossing roll rolling means, and that the equipment assembly is simple.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram illustrating the method of the present invention, Fig. 2 is a front view showing an embodiment of a steam injection machine as a steam injection means used in the steam injection step of the above method, and Fig. 3 is a schematic diagram illustrating the method of the invention. FIG. 4 and FIG. 5 are perspective views showing a portion of the above nonwoven fabric, respectively. FIG. 6 is a sectional view of a portion showing another example of the above nonwoven fabric. , FIG. 7 is a perspective view showing a part of still another embodiment of the same nonwoven fabric. (Explanation of symbols), 1... absorbent cotton band, 2... steam injection process, 21... steam injection machine as steam injection means, 3... embossing process, 3
1, 32... pressure roll, 41, 41'... recessed part,
42, 42'...protrusion.

Claims (1)

[Claims] 1. A steam injection step in which the absorbent cotton band is heated by a steam injection means, and immediately after the steam injection step, a pressing force of 1000 to 1000 is applied using a pair of upper and lower pressure rolls.
an embossing process in which the absorbent cotton band is pressed into a flat cloth under a high pressure of 20000 kg/cm ² ;
At least one of the pair of pressing rolls is formed into an embossing roll having point-like or linear protrusions, and the absorbent cotton band is embossed with the embossing roll while being heated with steam to form minute dot-like or fine line-like protrusions. 1. A method for producing a nonwoven fabric, characterized in that the fabric is configured to form a large number of concave portions. 2 The pressing force of the pressure roll against the absorbent cotton band is
10,000 to 15,000 Kg/cm ² , and the surface temperature of the pressure roll when receiving this pressing is 50 to 180°C.