JP2008169506A - Stretchable non-woven fabric - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonwoven fabric having stretching characteristics and standing repeated use, since there is a problem that the use of the non-woven fabric which is more preferable as a stretchable member in view of air-ventilation property and touch feeling to films, as disposable hygienic materials, such as diaper or the substrate of a pasting material, is increasing, and as the material used for the stretchable member, the non-woven fabric consisting of only with an elastomer having rubber elasticity is cited, however, in use in contact with a skin, the touch feeling is rubber like and it is not suitable in view of the touch feeling or the like. <P>SOLUTION: This stretchable non-woven fabric has partial fiber-gathering regions at a high density, separated from partial thermally compressed parts, on at least a surface layer of a stretched nonwoven fabric, and having a surface area rate of the fiber-gathering region at the high density of 5-70%. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a stretchable nonwoven fabric, and more particularly, to a stretchable nonwoven fabric used for disposable hygiene materials such as diapers, tape base materials, patch materials, bandages, and packaging materials that require stretchability.

In recent years, non-woven fabrics that are more preferable than films as stretchable members have been increasingly used for disposable sanitary materials such as diapers and base fabrics for patch materials in terms of air permeability and texture. Conventionally, as a material used for these elastic members, a nonwoven fabric made only of an elastomer having rubber elasticity can be mentioned. However, there is a problem that in touching the skin, the touch is rubber-like and not suitable in terms of texture. there were. In order to secure the texture and to easily set the necessary stretch performance, there is a non-elastomeric nonwoven fabric bonded to one or both sides of a rubber elastic stretch yarn (for example, Patent Document 1). However, when using elastic yarn, it will be tightened with a line instead of a surface when it comes into contact with the skin. Requires a high degree of difficulty such as high tension adjustment. In addition, a film using an elastic film (for example, Patent Document 2) is highly processed and complicated in order to adjust the tension at the time of laminating with the film and to make uniform holes for further breathability. There was a problem that a process was required and the cost was increased accordingly. Therefore, in order to facilitate the process and maintain the texture, there is one in which a nonwoven fabric is stretched and stretched in one direction (for example, Patent Documents 3 and 4). However, the stretching elastic modulus and the stretching recovery stress, which are stretching properties, are insufficient, and repeated stretching causes a problem that these properties are greatly lowered and the material is stretched. Moreover, in order to obtain unity, it may join partially after extending | stretching, but there existed a problem that extensibility will reduce conversely by joining a fiber.
JP-A-4-30847 Special table 2003-533374 gazette Japanese Examined Patent Publication No. 62-11106 Japanese translation of PCT publication No. 2003-506581

  An object of the present invention is to provide a stretchable nonwoven fabric that is excellent in the elongation elastic modulus and elongation recovery stress of the nonwoven fabric, can withstand repeated use, and does not impair the texture during practical use.

In order to improve the stretchability of the nonwoven fabric, the inventors focused on the state of the fibers in the nonwoven fabric surface fiber layer after the stretching treatment. As a result, in a non-woven fabric that has been simply stretched, the fibers are simply aligned in the stretching direction, and by repeatedly stretching, the fibers are loosened and the binding force of the fibers is lost. The resilience of trying to return is greatly reduced. In order to prevent this reduction in recovery force, it has been found that it is necessary to appropriately fix the fiber array enough to withstand repeated elongation. As a result of examining the degree of immobilization, when fusion with a cross-sectional deformation of the fiber, fusion so as to completely form a film, or high degree of immobilization by thermocompression represented by adhesion is performed. On the contrary, the extensibility in the fiber array disappears and sufficient stretchability cannot be obtained. Therefore, the inventors of the present invention do not crush the fibers in the surface fiber layer, are non-fusible, do not lose the degree of freedom as fibers, and are highly dense (fiber high-concentration region). And having a specific area ratio in this region, and providing a highly dense fiber area arranged in a specific range on the surface of the stretched nonwoven fabric in a pattern different from that of partial thermocompression bonding. It has been found that both the rate and the elongation recovery stress are improved, and furthermore, it has been achieved to obtain a stretchable nonwoven fabric that can withstand repeated use and does not impair the texture during practical use, thereby completing the present invention.
That is, the invention claimed in the present application is as follows.

(1) A non-woven fabric made of thermoplastic synthetic fiber, partially thermocompression bonded and stretched in one direction, and having a highly dense fiber area disposed in a different area from the partially thermocompression bonded area A stretchable nonwoven fabric, wherein the area ratio of the highly dense fiber area is 5 to 70%.
(2) The stretchable nonwoven fabric according to claim 1, wherein the nonwoven fabric has a spunbond fiber layer and / or a meltblown fiber layer made of an elastomer.
(3) The stretchable nonwoven fabric according to claim 1 or 2, wherein a ratio of the fiber layer made of the elastomer is 25 to 90% of the entire fiber layer.
(4) The stretch according to any one of claims 1 to 3, wherein a spunbond fiber layer serving as a surface layer is laminated on at least one surface of the spunbond fiber layer or the meltblown fiber layer. Non-woven fabric.
(5) The stretchable nonwoven fabric according to claim 4, wherein the spunbond fiber layer serving as the surface layer contains a crimpable fiber.
(6) The elastic modulus after repeating 100% elongation 5 times in a direction perpendicular to the stretching direction of the nonwoven fabric is 80% or more, and the retention is 90% or more. 5. The stretchable nonwoven fabric according to any one of 5.
(7) A non-woven fabric in which an elastomer melt-blown fiber layer is used as an intermediate layer, and a spunbond fiber layer is laminated on the upper and lower layers and integrated by partial thermocompression bonding so that the width penetration after stretching is 30% or more. After stretching treatment between rolls provided with a speed difference, it is passed between an embossing roll having a predetermined pattern and a flat elastic roll, and pressurized at a linear pressure of 100 to 1200 N / cm, and the fiber high-density area is 5 to 70%. The manufacturing method of the elastic nonwoven fabric characterized by forming in the range.

  The stretchable nonwoven fabric of the present invention is obtained by stretching a nonwoven fabric integrated by partial thermocompression bonding in one direction, and maintaining a non-fusible fiber shape within a range of 5 to 70% on the surface of the nonwoven fabric. Since it has a dense region, the elastic modulus of elasticity and the elongation recovery stress, which are elastic properties, are improved. For example, the elastic modulus after 5 cycles of 100% elongation is 80% or more, and the retention rate is 90% or more. It has excellent characteristics and can withstand repeated use.

  In the present invention, the nonwoven fabric to be stretched is not particularly limited as long as it is mainly composed of thermoplastic synthetic fibers and is partially thermocompression bonded. The fibers constituting the nonwoven fabric may be short fibers by so-called carding, paper making method, etc., but are preferably continuous filaments from the viewpoint of strength and productivity, for example, continuous melt-spun by the spunbond method or melt blow method. It is preferable to use a filament as a web or a web obtained by laminating these, and joining them by partial thermocompression bonding. In particular, from the viewpoint of ease of production process, it is preferable to form a multi-layer laminate such as a spunbond layer / melt blow layer / spunbond layer, or a spunbond layer / spunbond layer / spunbond layer, and further stretch properties. It is preferable that the intermediate layer sandwiched between the surface layers is a fiber layer made of a thermoplastic elastomer.

  As the types of fibers used for the nonwoven fabric, polyolefin fibers such as polypropylene, polyethylene, polyester fibers such as polyethylene terephthalate, polyamide fibers such as nylon are preferable from the viewpoint of strength or flexibility. Moreover, it is preferable to use these and a thermoplastic elastomer. If necessary, those mixed with these composite fibers, mixed fibers, further cellulosic fibers, and other fibers having special functions may be used. Examples of the thermoplastic elastomer that can be used include those that can be made into fibers such as polyolefin elastomers, polystyrene elastomers, polyamide elastomers, polyester elastomers, polyurethane elastomers, and polyvinyl chloride elastomers.

  The nonwoven fabric to be stretched is joined and integrated by partial thermocompression bonding in order to increase strength and flexibility. The thermocompression area ratio in this partial thermocompression bonding, that is, the thermocompression bonding area is from the viewpoint of strength retention and flexibility. 5 to 50% is preferable, and 5 to 20% is more preferable. Partial thermocompression can be performed, for example, by an ultrasonic method or through a web between heated embossing / flat rolls, whereby, for example, an embossed pattern that is a joint point such as a pinpoint shape or a rectangular shape is scattered over the entire surface. A dotted nonwoven fabric can be obtained. By the thermocompression treatment, the fiber layer is so-called fusion-bonded, and a part thereof has a film shape. Therefore, unlike the fiber dense collection area described later, the original shape as a fiber is not maintained and there is no degree of freedom.

  Further, the fineness of the spunbond fiber layer of the nonwoven fabric to be stretched is preferably 10 dtex or less, and more preferably 0.5 to 3.3 dtex or less from the viewpoint of flexibility and tactile feel as sanitary materials, daily life materials, and medical fabrics. Is more preferable.

Furthermore, it is more preferable to use crimped fibers for the fibers of the spunbond fiber layer of the surface layer of the present invention. Use of crimped fibers not only makes the resulting nonwoven fabric bulky, improves the texture, but also improves the stretch properties. The crimped fibers are preferably formed as continuous filaments having a helical crimp, and the number of crimps is preferably 2 or more / 25 mm.
The crimped fiber may be a modified cross-sectional yarn such as Y or V type, or a composite type fiber.

  Furthermore, the fibers of the spunbond fiber layer of the present invention may be formed into a round shape with a normal yarn cross section and a special shape obtained by deforming this. For crimped fibers with a single component, a special shape is used as a method from the viewpoint of crimping. In this case, what is necessary is just the shape which has a convex part or a recessed part of at least one part of thread | yarn cross-sectional shape. In addition, a crimped yarn with a single component may be physically formed by an asymmetric cooling method or the like in which the yarn is cooled non-uniformly during fiber production. Can be formed.

  The stretching treatment of the nonwoven fabric is to stretch the nonwoven fabric partially thermocompression-bonded in one direction. As a specific method, for example, a method similar to the stretching method between rollers described in JP-B-62-11106 is used. Methods. Moreover, since the holding | maintenance of an expansion / contraction characteristic improves more by giving the set property by a heat | fever, it is preferable to extend | stretch under a heating. The width of the stretched nonwoven fabric is preferably 30% or more, more preferably in the range of 40 to 60%.

  In the nonwoven fabric of the present invention, the highly dense fiber area different from the partial thermocompression bonding area is a highly dense area where the fibers are not crushed, and its area ratio to the surface is preferably 5 to 70%. More preferably, it is 20 to 55% of range, and particularly preferably 35 to 50%.

  The fiber structure of the fiber high-density region is different from the one subjected to thermocompression bonding, and maintains the shape as a fiber without causing the fiber to be crushed or fused, and has a degree of freedom as a fiber. Therefore, the effect which was excellent in the followable | trackability with respect to expansion | extension and recovery property is exhibited, and it has the followable | trackability which was excellent as a fiber structure especially with respect to repeated expansion / contraction. If the area ratio is less than 5%, it cannot be said that there is an effect that the stretchability is improved, and if it exceeds 70%, the elastic modulus is reduced along with the reduction in extensibility.

  In addition, the density of the nonwoven fabric in the thickness direction is preferably 80% or less, more preferably 50% or less, with respect to the total thickness, in order to obtain the effect of stretch characteristics, with the thickness of the fiber high-density region being 80% or less. is there.

The bulk density of the fiber high dense areas in the range of 0.1g ^/ cm ³ ~3.0g ^/ cm 3 are preferred. If it exceeds 3.0 g / cm ³ , it becomes a level similar to the bulk density of the thermocompression bonding part, and if it is less than 0.1 g / cm ³ , it becomes the same level as the non-thermocompression bonding part.

Based on the embodiment of the present invention, the relationship between the area ratio of the high-density fiber area and the elastic modulus after repeated 100% elongation is shown in FIG.
As shown in FIG. 5 (a), the area ratio of the fiber high-concentration area and the elastic modulus after repeated 100% elongation have a characteristic that shows a maximum value, and the area ratio of the fiber high-concentration area is 35 to 35%. It can be seen that the optimum range is shown at 50%.
Similarly, as shown in FIG. 5 (c), the retention rate and the stress at the time of return have the same effect as the characteristic of showing the maximum value in the area ratio of the fiber high-density area.

  Further, the shape or pattern of the high-density fiber area may be a point, linear, mesh, or turtle shell pattern as long as the high-density fiber area can be partially provided. 3 and 4 show typical shapes of the present invention.

  The method for imparting a high-density fiber area is not particularly limited as long as the fibers can be concentrated without being crushed within the above range. In view of the ease of the process, as a preferable method, in addition to using an engraved roll, a method of pressing a flat plate can be used, but the roll method is preferable in terms of production efficiency. A combination of one engraving roll and the other smooth and elastic roll may be a rubber roll or a paper roll as long as it is elastic. It is determined by setting the temperature and contact pressure of the upper and lower rolls according to the required performance of expansion and contraction of the obtained nonwoven fabric. In addition, as the timing of application of the fiber high-density area, post-processing after the stretching treatment may be performed, and from the viewpoint of production efficiency, it is possible to impart the speed difference at the time of the roller stretching treatment and to apply it with the roller itself that applies tension. desirable.

  The resulting nonwoven fabric has stretch properties in a direction perpendicular to the direction of stretching treatment, and as its performance, it has an elastic modulus of at least 80% after repeated 100% stretching and 5 times its retention rate. It is characterized in that it has at least 90%, and also has a retention rate of 50% return recovery stress after 5 times of 100% elongation at least 70%.

  As a more preferred embodiment, the elastic modulus after 5 times of 100% stretching is 85% or more, and the holding ratio is 95% or more. The stress retention is 75% or more.

Based on the example of the present invention, the relationship between the area ratio of the high-density fiber area and the elastic modulus after repeated 100% elongation is shown in FIG.
As shown in FIG. 5 (a), the area ratio of the fiber high-concentration area and the elastic modulus after repeated 100% elongation have a characteristic that shows a maximum value, and the area ratio of the fiber high-concentration area is 35 to 35%. It can be seen that the optimum range is shown at 50%.
Similarly, as shown in FIGS. 5B, 5 </ b> C, and 5 </ b> D, the retention rate, the recovery stress at the time of return, and the retention rate also show maximum values in the area ratio of the highly dense fiber area. Have the same effect.

Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples.
In addition, the nonwoven fabric of an Example and a comparative example was laminated | stacked by combining with the spun bond method and the melt blow method, and after manufacturing it by heat-stretching, it manufactured and the measuring method and the evaluation method are as follows. The surface high-density area of the fiber is indicated by the area ratio on the plane of the fiber surface, and the evaluation of the effect of improving the stretch property includes the elastic modulus after repeated 100% stretching and the repeated stretching after 100% stretching 5 times. The recovery stress at 50% return and the respective retention rates were measured and compared.
(1) Measurement of surface area ratio of highly dense fiber area Using a microscope manufactured by Keyence Corporation, the cross section and the surface of the obtained nonwoven fabric were enlarged at a magnification of 50 and measured. Explaining using the schematic diagram of the cross section of the nonwoven fabric in FIG. 1, 10 portions (a ₁ , a _2, etc.) are measured between the portions where the fibers start to be densely packed from the surface in the highly dense fiber area (cross section b). The width a of the fiber high-concentration region was set, the fiber high-concentration region portion on the surface was divided, and the area ratio of the unit area was defined as the surface area ratio of the fiber high-concentration region (see FIG. 1). When the embossed pattern of the fiber high-density area on the surface is complicated, the width of the fiber high-density area is measured and calculated as necessary to calculate the surface area ratio.
(2) Filling rate after stretching The dimension of the nonwoven fabric in the direction perpendicular to the stretching direction was measured before and after stretching, and the dimensional change rate was defined as the filling rate after stretching.
(3) Tensile test of a non-woven fabric with a measurement width of 5 cm and a length of 7 cm using Tensilon STM-101 manufactured by Toyo Baldwin Co., Ltd. at a grip width of 30 mm and a test speed of 50 mm / min. The stress at 100% elongation in the direction perpendicular to the direction in which the obtained nonwoven fabric was subjected to stretching treatment was measured (see FIG. 2a). It can be said that the smaller the stress at 100% elongation, the better the low elongation.
(4) Measurement of Elastic Modulus after Repeating 100% Elongation of Nonwoven Fabric 5 Times Using a Tensilon STM-101 manufactured by Toyo Baldwin Co., Ltd., a test piece having a width of 5 cm and a length of 7 cm was used. Move the head 30 mm (extend to 100%), hold for 1 minute (see FIG. 2 a), return the head to its original position at a speed of 50 mm / min, and move the head again 30 mm at the same speed after 3 minutes. . When stretching again, the rate of movement from when stress began to be applied until the head reached 30 mm was measured as the initial 100% stretched elastic modulus (see FIG. 2b). That is, the 100% elongation elastic modulus is a value obtained by subtracting the head movement rate until stress starts from the 100% head movement rate. It can be said that the larger the 100% elongation elastic modulus, the better the performance to return to the original state, and the better the expansion / contraction performance. The film was stretched 100% again, held for 1 minute, returned to its original position, and after 3 minutes, the 100% stretch modulus measured when it was stretched again was repeated the first time. The 100% elongation modulus at the fifth repetition is a value measured by repeating the above measurement.
(5) 100% elongation recovery of nonwoven fabric 50% Return stress A test piece having a width of 5 cm and a length of 7 cm is headed with a grip width of 30 mm and a tensile speed of 50 mm / min using Tensilon STM-101 manufactured by Toyo Baldwin Co., Ltd. 30 mm (extend to 100%), hold for 1 minute, return the head to its original position at a speed of 50 mm / min, 3 minutes later, move the head again at the same speed by 30 mm, hold for 1 minute, and again Return the head to its original position. When the head was returned to the original position again, the stress applied when the head returned 15 mm (at the time of 50% return) was measured as the initial stress at 100% elongation recovery and 50% return (see FIG. 2c). 100% elongation recovery 50% The greater the return stress, the greater the recovery force to return to the original state, and it can be said that the tightening force increases depending on the application used. The performance of the fifth repetition is a value measured by repeating the above measurement.

[Example 1]
Using a spunbond method, polypropylene (MFR = 40 measured under the conditions of Table 1 of JIS-K7210) is used as a raw material, and a spinneret with a spinning number of 2000H and a spinning diameter of 0.25mm is used and discharged at a spinning temperature of 230 ° C. Then, while cooling the discharged polymer from the side in the vicinity of the spinneret, the polymer was taken up by an air soccer traction take-up device so that the spinning speed was 3300 m / min and 2.0 dtex. The yarn exiting the tow-pull device was collected and conveyed as a web on a moving wire mesh conveyor. Next, a melt blow method is used on this web, using a polyolefin-based elastomer made of ethylene-octene copolymer as a raw material, and using a spinneret with a spinning number of 2200H and a spinning diameter of 0.22 mm, at a head temperature of 245 ° C. The web was laminated by discharging and spraying at a spraying distance of 100 mm and a hot air temperature of 360 ° C. Subsequently, on this laminated web, the yarn discharged and pulled by the same method as the spunbond method was deposited and laminated. The web was conveyed and passed between pin pattern embossed / flat rolls with a partial thermocompression area ratio of 7% heated to 110 ° C. to obtain a partially thermocompressed web. Subsequently, the web was passed between two pairs of nip rolls, and hot air at 100 ° C. was blown onto the web between the nip rolls, and the rear nip roll was stretched with a speed difference of 1.5 times. At this time, the rear nip roll was pressed at a linear pressure of 60 kg / cm using a turtle shell line pattern emboss heated to 80 ° C. and a rubber roll having a surface hardness of 50 degrees (JIS-A hardness). A non-woven fabric was obtained in which the surface area ratio of the highly dense fiber area was 35%, the basis weight was 150 g / m ² , and the weight ratio of each fiber layer was 20 wt% for the upper layer, 60 wt% for the elastomer layer, and 20 wt% for the lower layer.
The obtained non-woven fabric is repeatedly 85% in the initial stage of 100% elongation elastic modulus in the direction perpendicular to the direction to be stretched, the elastic modulus after 5 times is 81%, and the retention rate is 95%. And, it was excellent in stretch properties. Further, the 100% elongation stress was 11.5 N / 5 cm width, the 100% elongation recovery, 50% reversion stress, and the fifth holding ratio were 75%. The results are shown in Table 1.

[Example 2]
In the same manner as in Example 1 except that the basis weight of the obtained nonwoven fabric was 92 g / m ² and the weight ratio of each fiber layer was 40 wt% for the upper layer, 30 wt% for the elastomer layer, and 40 wt% for the lower layer, A nonwoven fabric having a surface area ratio of 35% in a dense area was obtained. The results are shown in Table 1.

[Example 3]
In the same manner as in Example 1, using the spunbond method, polypropylene was used as a raw material, and it was collected and conveyed as a web on a wire mesh conveyor so as to be 2.0 dtex. Next, using a spunbond method, a polyolefin-based elastomer made of ethylene-octene copolymer was used as a raw material, and a spinneret having a spinning number of 2000H and a spinning diameter of 0.25 mm was discharged at a spinning temperature of 220 ° C. and discharged. While cooling the polymer from the side in the vicinity of the spinneret, the polymer was taken up with an air soccer pulling / drawing device so that the spinning speed was 2700 m / min and 3.3 dtex. The yarn exiting the pulling / pulling device was deposited and laminated on the above-mentioned spunbond web made of polypropylene. Subsequently, on this laminated web, the yarn discharged and pulled by the same method as the spunbond method made of polypropylene was deposited and laminated. The web was conveyed and passed between pin pattern embossed / flat rolls with a partial thermocompression area ratio of 7% heated to 110 ° C. to obtain a partially thermocompressed web. Stretching was performed in the same manner as in Example 1, the surface area ratio of the high-density fiber area was 35%, the basis weight was 124 g / m ² , and the weight ratio of each fiber layer was 20 wt% for the upper layer, 60 wt% for the elastomer layer, and 20 wt% for the lower layer. % Nonwoven fabric was obtained. The results are shown in Table 1.

[Example 4]
Example 1 except that the long fibers melt-extruded from the irregular nozzle were cooled from the side in the vicinity of the nozzle so that the fibers of the spunbond web made of polypropylene in Example 1 had a helical crimp. Similarly, a nonwoven fabric having a surface area ratio of 35% and a basis weight of 155 g / m ² was obtained. The results are shown in Table 1.

[Example 5]
Nylon 6 was used as a raw material for the spunbond web in Example 1, and this was also discharged at a spinning temperature of 260 ° C. Further, the surface area ratio of the fiber high-density area was 35% in the same manner as in Example 1 except that the laminated web was subjected to thermocompression bonding using a textured pattern embossing roll having a partial thermocompression area ratio of 14%. A nonwoven fabric having a basis weight of 150 g / m ² was obtained. The results are shown in Table 1.

[Example 6]
The raw material of the spunbond web in Example 1 is discharged at a spinning temperature of 300 ° C. using polyester, the raw material of the meltblown web is discharged at a head temperature of 300 ° C. using a polyester elastomer, the spray distance is 100 mm, and the hot air temperature is 400 Spraying was performed at 0 ° C. Moreover, the surface of the fiber high-density area | region was carried out similarly to Example 1 except having performed the thermocompression bonding to the laminated | stacked web using the horizontal oblong pattern embossing roll of the partial thermocompression-bonding area rate 11% heated at 180 degreeC. A nonwoven fabric having an area ratio of 35% and a basis weight of 151 g / m ² was obtained. The results are shown in Table 1.

[Example 7]
In Example 1, a horizontally long embossed emboss and a rubber roll having a surface hardness of 50 degrees (JIS-A hardness) were used for the rear nip roll when drawing, and the surface area ratio of the fiber high-density area was 50%. Produced a nonwoven fabric having a basis weight of 150 g / m ^{2 in} the same manner as in Example 1. The results are shown in Table 1.

[Example 8]
In Example 1, except that a pin pattern embossing and a rubber roll having a surface hardness of 50 degrees (JIS-A hardness) were used for the rear nip roll during stretching, and the surface area ratio of the fiber high-density area was 15%. In the same manner as in Example 1, a nonwoven fabric having a basis weight of 150 g / m ² was obtained. The results are shown in Table 1.

[Example 9]
Except that the web was formed so that the fineness of the spunbond made of polypropylene in Example 1 was 1.0 dtex, the surface area ratio of the highly dense fiber area was 35% and the basis weight was 150 g / m. ² nonwoven fabric was obtained. The results are shown in Table 1.

[Example 10]
In the same manner as in Example 1, except that the web obtained by laminating only the melt blown web made of polyolefin elastomer on the spunbond web made of polypropylene in Example 1 was used, the surface area ratio of the highly dense fiber area was as follows. A nonwoven fabric with a weight of 35% and a basis weight of 110 g / m ² was obtained. The results are shown in Table 1.

[Comparative Example 1]
In Example 1, a pin pattern embossing roll / flat elastic rubber roll is used for the rear nip roll when stretching, and the laminated web before stretching is placed under the flat elastic rubber roll so that the pass line is S-shaped. The pin pattern embossing roll / flat elastic rubber roll was passed in the opposite direction so that the upper side of the pin pattern embossing roll was passed. In addition, a nonwoven fabric having a surface area ratio of 0% and a basis weight of 150 g / m ² was obtained in the same manner as in Example 1 except that the rear nip roll was stretched without pressure.
The obtained non-woven fabric was repeatedly stretched in the direction perpendicular to the direction to be stretched, the initial 100% stretch modulus was 81%, the modulus after 5 cycles was 68%, its retention rate was 84%, , 100% elongation recovery 50% rebound stress retention rate for the fifth repetition was 49%, which was not excellent in stretch properties. The results are shown in Table 1.

[Comparative Example 2]
In Example 1, a mesh pattern embossing roll and a rubber roll having a surface hardness of 50 degrees (JIS-A hardness) were used as the nip rolls at the rear of the drawing, so that the surface area ratio of the high-density fiber area was 80%. Except for the above, a nonwoven fabric having a basis weight of 150 g / m ² was obtained in the same manner as in Example 1.
The obtained non-woven fabric is repeatedly 75% in the initial direction of 100% elongation elastic modulus in the direction perpendicular to the direction of stretching treatment, the elastic modulus after 5 times is 65%, the retention rate is 87%, , 100% elongation recovery 50% rebound stress retention rate for the fifth repetition was 26%, which was not excellent in stretch properties. The results are shown in Table 1.

[Comparative Example 3]
In Example 1, except that a turtle shell line pattern embossed / flat metal roll was used for the rear nip roll when stretching, the thermocompression area ratio by the turtle shell line pattern was 40%, and the basis weight was the same as in Example 1. A nonwoven fabric of 150 g / m ² was obtained.
The obtained nonwoven fabric broke until it reached 100% elongation in a direction perpendicular to the direction of stretching treatment, and was not excellent in stretch properties. The results are shown in Table 1.

[Comparative Example 4]
When the nonwoven fabric in Example 1 was stretched, the surface area ratio of the highly dense fiber area was 35% in the same manner as in Example 1 except that the rear nip roll was stretched with a speed difference of 1.3 times. Thus, a nonwoven fabric having a stretched nonwoven fabric width of 25% and a basis weight of 126 g / m ² was obtained. The obtained non-woven fabric is repeatedly 73% in the initial stage of 100% elongation modulus in the direction perpendicular to the direction to be stretched, the modulus after 5 times is 60%, the retention rate is 82%, 100% elongation recovery 50% rebound stress 5th time holding ratio was 54%, which was not excellent in stretch properties. The results are shown in Table 1.

  The stretchable nonwoven fabric of the present invention includes sanitary materials such as diapers and napkins, base fabrics such as patch materials, packaging materials, tape base materials, and materials for parts that require stretchability, such as simple masks, bandages, and clothing. Suitable for and products.

The cross-sectional schematic diagram of the fiber high concentration area | region of the nonwoven fabric of this invention. The figure which shows the expansion-contraction characteristic of a nonwoven fabric with an elongation stress curve. a is the stress at 100% elongation, b is the elastic modulus at 100%, and c is the stress at 100% elongation recovery and 50% return. The top view which shows the example of the embossing pattern for forming the fiber high concentration area | region of this invention. a) is a pin pattern, and b) is an example of a horizontally long circular pattern. The top view which shows another example of the embossing pattern for forming the fiber high concentration area | region of this invention. c) shows a turtle shell line pattern, and d) shows a grid pattern. The graph which shows the relationship between the area ratio of a fiber high concentration area | region, and the elasticity modulus after a 100% expansion | extension 5 times in the Example of this invention. a) is the relationship between the area ratio of the highly dense fiber area and the elastic modulus after 5 repetitions of 100% elongation, and b) is the relationship between the area ratio of the fiber high density area and the elastic modulus retention after 5 repetitions of 100% elongation. C) Relationship between the area ratio of highly dense fiber area and 50% return recovery stress after 5 times of 100% stretching, and d) 50% return area ratio of highly dense fiber area and 5 times of 100% stretching repeatedly. The relationship with the retention rate of time recovery stress is shown.

Claims (7)

  A non-woven fabric made of thermoplastic synthetic fiber, partially thermocompression-bonded and stretched in one direction, and having a highly dense fiber area disposed in an area different from the partially thermocompression-bonded area, A stretchable nonwoven fabric having an area ratio of 5 to 70% in a highly dense area.   The stretchable nonwoven fabric according to claim 1, wherein the nonwoven fabric has a spunbond fiber layer and / or a meltblown fiber layer made of an elastomer.   The stretchable nonwoven fabric according to claim 1 or 2, wherein a ratio of the fiber layer made of the elastomer is 25 to 90% of the entire fiber layer.     The stretchable nonwoven fabric according to any one of claims 1 to 3, wherein a spunbond fiber layer serving as a surface layer is laminated on at least one surface of the spunbond fiber layer or the meltblown fiber layer.   The stretchable nonwoven fabric according to claim 4, wherein the spunbond fiber layer serving as the surface layer contains a crimpable fiber. The elastic modulus after 100% elongation and 5 repetitions in a direction perpendicular to the stretching direction of the nonwoven fabric is 80% or more, and the retention is 90% or more. The stretchable nonwoven fabric according to crab. An elastomer meltblown fiber layer is used as an intermediate layer, and a spunbond fiber layer is laminated on the upper and lower layers, and a non-woven fabric that is integrated by partial thermocompression bonding has a speed difference so that the penetration ratio after stretching is 30% or more. After stretching between the provided rolls, it is passed between an embossing roll having a predetermined pattern and a flat elastic roll, and pressurized at a linear pressure of 100 to 1200 N / cm to form a highly dense fiber area in the range of 5 to 70%. A method for producing a stretchable nonwoven fabric.

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