JPH05263344A - Stretchable nonwoven fabric of filament and its production - Google Patents

Abstract

PURPOSE:To produce nonwoven fabric of filaments having excellent elasticity and tensile strength. CONSTITUTION:Latently crimping conjugate type filaments (a) and not latently crimping conjugate type filaments (b) comprising a high-melting component and a low-melting component are prepared. The low-melting component of the filaments (a) and (b) are exposed at least to the surface of fibers. The filaments (a) and (b) are uniformly blended to give web 14 of filament. The web 14 of filament is fed to embossing devices 15 and 16 and provided with point welding regions. In the point welding regions, parts between the filaments (a), parts between the filaments (b) and parts between the filaments (a) and filaments (b) are welded by melting and solidification of the low-melting component. Simultaneously with the formation of the point welding regions or after the formation, the web of filament is heat-treated. By the heat treatment, the filaments (a) develop crimping and the filaments (b) do not substantially develop crimping.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a long fiber non-woven fabric excellent in stretchability and tensile strength and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Nonwoven fabrics have hitherto been used for various purposes such as clothing, industrial materials, civil engineering and construction materials, agricultural and horticultural materials, life-related materials, medical hygiene materials and the like. Among them, especially non-woven fabrics used for medical hygiene materials such as pap materials and supporters, because it is easy to follow the movement of the human body, or because it is easy to adapt to the human body,
Elasticity is required. It is known that crimped fibers having good stretchability may be used as the constituent fibers in order to give stretch to the nonwoven fabric.

As a method for producing a long-fiber nonwoven fabric having stretchability using crimped long fibers, for example, Japanese Patent Publication No.
The method described in Japanese Patent Publication No. -21318 is known. In this method, a latent crimpable eccentric core-sheath type composite continuous fiber composed of a low melting point component and a high melting point component is accumulated to obtain a continuous fiber web, and the continuous fiber web is heated to obtain a composite continuous fiber. The fiber is crimped and the low melting point component, which is the sheath component, is melted. By this method, it is possible to obtain a long-fiber nonwoven fabric composed of long fibers having crimps and having the low-melting components fused to each other. However, in this long-fiber nonwoven fabric, since the long fibers are fused to each other over the entire area of the nonwoven fabric, there are few areas where the long fibers can freely expand and contract, and it is possible to impart sufficient elasticity to the nonwoven fabric. Can not.

For this reason, as described in Japanese Patent Laid-Open No. Hei2-191757, there is provided a point-fused area at intervals without fusing the long fibers with each other over the entire area of the nonwoven fabric. It is conceivable to fuse the long fibers to each other only in this area. According to this method, the long fibers are not fused to each other in the area other than the point fusion area, the long fibers can freely expand and contract in the relatively large area, and the long fibers excellent in elasticity are obtained. A non-woven fabric is obtained.

By the way, in order to reduce the elasticity of the long-fiber nonwoven fabric to a desired extent, non-latent crimpable long fibers may be mixed as constituent fibers. For example, general polyolefin-based long fibers, polyester-based long fibers and the like may be mixed. However, when such general filaments are mixed, the following drawbacks may occur. That is, when a non-latent crimping filament having a melting point which is the same as or lower than the melting point of the low melting point component of the latent crimpable conjugate filament is used, the non-latent crimping property is provided when the spot fusion zone is provided. The long fibers were sometimes melted throughout to completely lose the fiber morphology, and the tensile strength of the resulting stretchable long-fiber nonwoven fabric was sometimes extremely reduced. Further, when a non-latent crimping filament having a melting point higher than that of the low melting point component is used, fusion between latent crimping filaments may be obstructed in the point fusion area, and thus obtained. There have been cases where the stretchable long-fiber nonwoven fabric cannot be given sufficient tensile strength.

[0006]

Therefore, the present invention provides a non-latent crimping composite type long fiber composed of a low melting point component which is the same as the low melting point component of the latent crimpable filaments and a high melting point component. By mixing the fibers with the latent crimping composite long fibers, the non-latent crimping composite long fibers lose the fiber morphology or form the latent crimping composite fibers when forming the spot fusion zone. It is intended to prevent the fusion between the mold long fibers from being hindered so that the tensile strength of the obtained long fiber non-woven fabric does not decrease.

[0007]

That is, according to the present invention, a composite continuous fiber A composed of a high melting point component M ₁ and a low melting point component M ₂ is used.
When, the long fibers A with composed of a high melting point component M ₃ and the low melting point component M ₂ will be uniformly mixed with the composite long fibers B of different composite forms, long fiber A is have a crimp However, the long fibers B have substantially no crimp, and the long fibers A and B
The low melting point component M ₂ of the long fibers A and B is arranged so as to be exposed on at least the surface of the long fibers A and B.
The stretchable long-fiber nonwoven fabric is characterized in that it has point fusion zones in which long fibers A, long fibers B, and long fibers A and B are fused by the low melting point component M ₂ of is there. Further, the present invention is a latent crimpable composite continuous fiber a obtained by melt-compositing the high melting point component M ₁ and the low melting point component M ₂ and exposing the low melting point component M ₂ at least on the surface thereof.
And a high-melting point component M ₃ and a low-melting point component M ₂ are obtained by melt-composite spinning, the low-melting point component M ₂ is exposed at least on the surface thereof, and the non-latent different from the long fiber a in a composite form. The crimpable composite long fibers b are uniformly mixed to obtain a long fiber web, and the long fiber web is partially heated and optionally pressed to give the low melting point component M ₂ of the long fibers a and b. Is melted to form a point fusion area where the long fibers a, the long fibers b, and the long fibers a and b are fused, and at the same time as or after the point fusion area is provided, the entire long fiber web is formed. The present invention relates to a method for producing a stretchable long-fiber nonwoven fabric, which is characterized by heat-treating to cause crimps in the long-fiber a.

In the present invention, the expression "long fiber a" in lower case English letters means a long fiber in which crimps have not yet been developed, and a long fiber A in upper case English letters.
The expression, means a long fiber in which crimps are expressed. Also, the expression "long fiber b" in lowercase letters in English means a non-latent crimping composite long fiber mixed with a long fiber a in which crimps have not yet been developed. The expression "B" means a long fiber mixed with the long fiber A in which crimps are expressed.

First, in the present invention, a latent crimpable composite continuous fiber a and a non-latent crimpable composite continuous fiber b having a composite form different from that of the continuous filament a are prepared. The long fiber a is obtained by melt-compositing the high melting point component M ₁ and the low melting point component M ₂ and the low melting point component M ₂ is at least the long fiber a.
Is exposed on the surface of. The reason that the low melting point component M ₂ is exposed on the surface of the long fiber a is that the component M ₂ is an adhesive component between the long fibers. As the high melting point component M ₁ and the low melting point component M ₂ , different types of thermoplastic resins having different melting points may be selected. For example, polyester resin (M ₁ component) and polyamide resin (M ₂ component), polyester resin (M ₁ component) and polyolefin resin (M ₂ component), polyamide resin (M ₁ component) and polyolefin resin (M ₂ component), polyester resin or polyamide resin or polyolefin resin (M ₁ component) and ethylene-vinyl acetate copolymer resin (M ₂ component) and the like can be selected. Further, the same kind of thermoplastic resin having a different melting point may be selected. For example, a high melting point polyester resin (M ₁ component) and a low melting point polyester resin (M ₂ component),
High melting point polyamide resin (M ₁ component) and low melting point polyamide resin (M ₂ component), high melting point polyolefin type resin (M ₁ component) and low melting point polyolefin type resin (M ₂ component)
Etc. can be selected. Here, as the polyester-based resin, polyethylene terephthalate, polybutylene terephthalate, or a copolyester having these as main components can be used. Polyamide resins include nylon 6, nylon 46, nylon 66
Alternatively, nylon 610 or copolymer nylon having these as main components can be used. Polyolefin, polypropylene, high-density polyethylene,
Linear low density polyethylene, ethylene-propylene copolymer and the like can be used. In the present invention, the melting point of the thermoplastic resin is measured by the following measuring method. That is, a differential scanning calorimeter DSC-2 type manufactured by Perkin Elmer was used to measure the temperature that gives the extreme value of the melting absorption curve measured at a temperature rising rate of 20 ° C./min, and this was taken as the melting point.

The long fiber b is also obtained by melt-composite spinning of the high melting point component M ₃ and the low melting point component M ₂ , and the low melting point component M ₂ is exposed at least on the surface of the long fiber b. Is. The reason why the low melting point component M ₂ is exposed on the surface of the long fiber b is the same as in the case of the long fiber a. The reason for using the same low-melting-point component M ₂ as the low-melting-point component of the long fiber a is to complete fusion between the long-fiber a and the long-fiber b. As the high melting point component M ₃ and the low melting point component M ₂ , those having the same combination as in the case of the long fiber a can be selected. The high melting point component M ₃ of the long fiber b and the high melting point component M ₁ of the long fiber a may use the same thermoplastic resin, or may use different thermoplastic resins.

Both the long fibers a and the long fibers b are composite type long fibers composed of a high melting point component (M ₁ or M ₃ ) and a low melting point component M ₂ , but have different composite forms. .. That is,
The long fibers a are in a (latent crimping) composite form that can develop crimps when heated. Specifically, a parallel type (FIG. 2), an eccentric core-sheath type, an asymmetrical division type (FIG. 4), etc. can be adopted. When adopting an eccentric core-sheath type composite long fiber in which the cross section of the long fiber a is circular, the eccentricity defined by the following formula (a) should be 15 or more. Is preferred. This is because if the eccentricity is less than 15, the crimp developability tends to decrease. Eccentricity ratio = [(distance between center of diameter of cross section of long fiber and center of diameter of core component) x 100] / [(diameter of cross section of long fiber) / 2] ... (a) Such a composite The long fiber a having a morphology has a high melting point component M ₁
Since the low melting point component M ₂ and the low melting point component M ₂ have different thermal characteristics, that is, a heat shrinkage factor, heating causes the low melting point component M ₂ to be inside, and a spiral crimp or the like is developed. The long fibers b have a (non-latent crimping) composite form that does not substantially develop crimps when heated. Specifically, a concentric core-sheath type (FIG. 1), a point symmetric type (FIG. 6), etc. can be adopted. Here, the fact that the crimp is not substantially expressed means that when the desired crimp is expressed in the long fiber a,
This means that the number of crimps in the long fiber b does not exceed 5/25 mm. When the number of crimps exceeds 5/25 mm, it cannot be said that it is a non-latent crimped filament, and the mixture of non-latent crimped filaments increases the stretchability of the filament non-woven fabric. The effect of lowering is reduced. In the long fibers a or during b, the ratio of the high melting point component (M ₁ or M ₃₎ and the low-melting component M ₂ is a high melting point component (M ₁ or M ₃₎ 30 to 70 parts by weight and a low melting component M ₂ It is preferably in the range of 30 to 70 parts by weight. In particular, 50 parts by weight of the high melting point component (M ₁ or M ₃ ) and 50 parts by weight of the low melting point component M ₂
Most preferred. Further, the cross-sectional shape of the whole long fiber is generally circular, but the shape is not limited to this, and it may be a deformed shape or a hollow shape. Examples of the combination of the long fibers a and b having different composite forms include, for example, the parallel type shown in FIG.
The concentric core-sheath type shown in FIG. 4, the parallel type having a triangular section shown in FIG. 4 and the concentric core-sheath type having a triangular section shown in FIG. 3 can be adopted. In particular, it is preferable to adopt the parallel type and the concentric sheath type shown in FIGS. 2 and 1.

In order to carry out melt composite spinning of the long fibers a and the long fibers b, any conventionally known method can be adopted. In the present invention, particularly as shown in FIG. 5 and FIG.
It is preferable to perform melt composite spinning by the following method using a spinning device. FIG. 5 is a schematic diagram showing an apparatus for producing a stretchable long-fiber nonwoven fabric according to an example of the present invention, including a spinning apparatus, and FIG. 6 is a melt-composite spinning apparatus used for discharging long fibers a and b. 4 is a cross-sectional view showing an example of No. 4 of FIG. The thermoplastic resin selected as the high melting point component (M ₁ component = M ₃ component) is charged into the hopper 1, while the thermoplastic resin selected as the low melting point component is charged into the hopper 5. Then, after being melt-extruded by the extruders 2 and 7, they are separately weighed by the weighing units 3 and 8 and introduced into the melt-composite spinning apparatus 4. The melt-measured high-melting-point component is introduced into the introduction passage 22 provided in the distribution plate 21 of the melt-composite spinning device 4, while the melt-measured low-melting-point component is introduced into the introduction passage 23. Below the distribution plate 21, a filtration plate 24, an intermediate plate 26, and a mouth plate 27 are arranged in this order. The high-melting point component and the low-melting point component are separately filtered by a filter 25 or the like in the filtering plate 24, and separately metered and distributed by the orifice in the intermediate plate 26. The distributed high-melting-point component and low-melting-point component are composited on the upper part of the die plate 27 and discharged from the parallel type composite spinning hole 29 and the concentric sheath-type composite spinning hole 28. Then, both of them can be pulled and drawn by the sucker 11 and cooled by the cooling device 10 to obtain long fibers a and long fibers b having different composite forms. If such a method is adopted, the long fiber a and the long fiber b can be obtained at the same time, and the long fiber a and the long fiber b can be opened by the fiber opening device provided in the lower part of the soccer 11 and accumulated on the collecting conveyor 13. For example, the long fiber web 14 in which the long fibers a and b are uniformly mixed can be obtained. The ratio of the high melting point component and the low melting point component in the long fiber can be arbitrarily changed by changing the orifice diameter of the intermediate plate 26 or the number of orifices.

By the method as described above, the long fiber web 14 in which the long fibers a and the long fibers b are uniformly mixed can be obtained. At this time, the long fibers a and b need to be uniformly mixed. This is because if there are locations where only the long fibers a or b are unevenly distributed, locations with different stretchability will occur, and uniform stretchability will not be exhibited over the whole. The mixing ratio of the long fibers a and b is preferably 20 to 80 parts by weight of the long fibers a and 80 to 20 parts by weight of the long fibers b. Particularly preferably, 30 to 70 parts by weight of the long fiber a and 70 to 70 parts by weight are used.
It is advisable to mix 30 parts by weight of the long fibers b, most preferably 40 to 60 parts by weight of the long fibers a and 60 to 40 parts by weight of the long fibers b. If the mixing ratio of the long fibers a exceeds 80 parts by weight, the effect of reducing the stretchability of the long fiber non-woven fabric due to the mixing of the long fibers b tends to decrease. Further, when the mixing ratio of the long fibers b exceeds 80 parts by weight, the long fiber non-woven fabric is greatly deteriorated in elasticity, and it tends to be difficult to impart desired elasticity to the long fiber non-woven fabric.

Spot fusion zones are formed on the long fiber web 14 by methods known in the art. For example, the long fiber web 14 is introduced into an embossing device including a heating uneven roll 15 and a smooth roll 16 as shown in FIG. And
Heat and pressure are applied to the portions of the long fiber web 14 corresponding to the convex portions of the concavo-convex roll 15 to melt the low melting point components of the long fibers a and b, thereby forming a point fusion area where the long fibers are fused. To form. At this time, in the area other than the point fusion area, the low melting point component is not melted, and the long fibers are not fused and exist in a free state. In the present invention, since the low melting point components of the long fibers a and b are the same component M ₂ , it is easy to control the temperature of the concavo-convex roll 15. Uneven roll 15
The temperature of 5 to 30 is generally higher than the melting point of the low melting point component.
It may be set at a temperature lower by ℃. Than the melting point of the low melting point component
When the temperature is set higher than 5 ° C. lower than the low temperature, the low melting point component may be fused even in a portion other than the convex portion of the concavo-convex roll 15, and the flexibility and stretchability of the obtained long-fiber nonwoven fabric are deteriorated. A tendency arises. Further, if the temperature is set lower than the temperature lower than the melting point of the low melting point component by 30 ° C., the long fiber web 14 is likely to be wound around the concavo-convex roll 15, and the operability during the production of the nonwoven fabric tends to be deteriorated. Further, in the point fusion area, the fusion between the long fibers tends to be insufficient. The temperature of the smooth roll 16 is generally set to be equal to or lower than the set temperature of the uneven roll 15. In particular, the temperature of the smooth roll 16 is
A temperature lower than the set temperature of the concavo-convex roll 15 (for example, 20 ° C)
It is preferable to set the temperature to a low temperature). This is because the smooth roll 16 having a low set temperature can avoid the possibility that the low melting point component will be fused at a portion other than the convex portion of the concavo-convex roll 15. The linear pressure applied to the continuous fiber web 14 by the convex portions of the uneven roll 15 and the smooth roll 16 is preferably about 2 to 100 kg / cm. When the linear pressure is less than 2 kg / cm, the low melting point component generally does not melt when the temperature of the concavo-convex roll 15 is set below the melting point of the low melting point component. If the linear pressure exceeds 100 kg / cm,
There is a risk of puncturing the spot fusion area. In addition, the total area of the convex portions of the concavo-convex roll 15 is 3 to 40 with respect to the total area of the roll.
% Is preferred. If the total area of the convex portions is less than 3%, the proportion of the spot-fused areas formed is too small, and it tends to be difficult to impart sufficient strength and shape retention to the resulting nonwoven fabric. On the other hand, if the total area of the convex portions exceeds 40%, the proportion of the spot fusion bonded areas becomes too large, and the stretchability of the resulting nonwoven fabric tends to decrease.

The above is the uneven roll 15 and the smooth roll 16
Although the method of forming a point fusion zone by this action by applying heat and pressure by using and is used, the uneven roll 15 and the smooth roll 16 are used, and only the heat is mainly applied by the action of ultrasonic waves. It is also possible to provide to form spot fusion zones.

As described above, the long fiber web 14 is provided with the spot fusion zone. In this point fusion zone, the long fibers a are melted and solidified by the low melting point components of the long fibers a and b.
Space, between the long fibers b, and between the long fibers a and b are fused.
In addition, the long fiber web 14 is given a certain strength and shape retention. In the present invention, it is necessary to develop crimp in the long fiber a at the same time as providing the point fusion area or after providing the point fusion area. That is, after the long fiber web 14 is given a certain shape, the long fibers a are crimped to shrink the whole long fiber web 18. Then, the obtained long-fiber nonwoven fabric 20 can be stretched at least to the form before shrinkage, and the desired stretchability can be imparted to the long-fiber nonwoven fabric 20. If the point fusion-bonded area is provided after the long fiber a has been crimped and contracted, the long fiber a tends to be fixed in the shape after the contraction, and thus the obtained nonwoven fabric may have sufficient stretchability. You can't do it.

In order to develop the crimp in the long fiber a, it is generally introduced into the heat treatment device 17. Heat treatment equipment 17
Thus, when a certain amount of heat is applied to the long fiber a, the crimp is developed in the long fiber a based on the difference in the heat shrinkage rate between the low melting point component M ₂ and the high melting point component M ₁ . Generally, under a predetermined temperature condition, the low-melting point component of the long fiber a has a larger heat shrinkage ratio than the high-melting point component. Therefore, the long fiber a develops crimps such that the low melting point component is inside. Further, the crimp development of the long fiber a occurs in an area other than the spot fusion bonding area. In the point fusion area, the filaments a are fused, so that the crimp no longer develops. As the heat treatment device 17 for developing the crimp, it is preferable to use a hot air circulation type treatment machine so that the inside of the long fiber web 18 can be uniformly heat treated. That is, when heat treatment is performed so that the hot air penetrates the long fiber web 18, heat is uniformly applied to the entire long fiber web 18 (all in the longitudinal and lateral directions and the thickness direction). The temperature for the heat treatment may be arbitrarily determined in consideration of the types of the low melting point component and the high melting point component, the type of the heat treatment apparatus, the processing speed, the processing time, and the like. Generally, it is preferable to apply a temperature lower than the melting point of the low melting point component by 30 ° C. or more during the heat treatment. The stretchable long-fiber nonwoven fabric can be obtained by the method described above. The manufacturing method described above is a typical manufacturing method of the elastic long fiber nonwoven fabric according to the present invention.

The stretchable long-fiber nonwoven fabric according to the present invention obtained by the above-described representative method has only the heat applied to the crimped long fibers A and the long fibers b due to the crimp development of the long fibers a. And the long fibers B of 1. are uniformly mixed. Therefore, the long fiber A is a composite type long fiber A in which the high melting point component M ₁ and the low melting point component M ₂ are combined, and the long fiber B is formed by combining the high melting point component M ₃ and the low melting point component M _2. It is a composite type long fiber B. Further, the composite form of the long fibers a and b is different, the long fiber A has a predetermined crimp, and the long fiber B has substantially no crimp. On the other hand, in the point fusion zone, the long fibers A, the long fibers B, and the long fibers A and B are fixed by the low melting point component M ₂ exposed on the surface of the long fibers A and B. ..

The mixing ratio of the long fibers A and B is preferably that 20 to 80 parts by weight of the long fibers a and 80 to 20 parts by weight of the long fibers b are mixed to form the long fiber web 14. Similarly, 20 to 80 parts by weight of long fiber A and 80 to 20 parts by weight of long fiber B
It is preferable that and are mixed. Further, since it is preferable that the composite form of the long fibers a is the parallel composite form and the long fibers b is the concentric core-sheath composite form, the composite form of the long fibers A is also the parallel composite form, The composite form of the long fibers B is preferably a concentric core-sheath composite form.
The crimping area ratio of the spot fusion zone is generally determined within the range of 4 to 50%. Particularly preferably, it is about 6 to 45%, most preferably about 8 to 40%. Crimp area ratio is 4
If it is less than%, the strength and shape retention of the long-fiber nonwoven fabric tend to decrease. On the other hand, if the pressure-bonded area ratio exceeds 50%, the flexibility tends to decrease. The pressure-bonded area ratio is measured by the following measuring method.
That is, using a small piece of long fiber non-woven fabric, magnified and photographed with a scanning electron microscope, with respect to the area of the minimum repeating unit, the average value when the ratio of the total area of the point pressure bonding area is measured 10 times individually. is there. Further, the reason why this pressure-bonding area ratio is larger than the ratio of the total area of the convex portions to the total area of the rolls of the concavo-convex roll 15 is that the long-fiber a is formed at the same time when the spot fusion area is provided by the concavo-convex roll 15. Develop crimps on
This is to shrink the entire long fiber web 18.

The elastic long-fiber nonwoven fabric according to the present invention preferably has the following physical properties. That is, 30%
The elongation recovery rate during elongation is preferably 20% or more in both length and width. Here, the elongation recovery rate at 30% elongation is determined by the following measuring method. That is, using Tensilon UTM-4-1-100 manufactured by Toyo Baldwin, JISL-
According to the strip method described in 1096A, a tensile test was performed on a sample piece having a sample width of 5 cm and a sample length of 10 cm at a tensile speed of 10 cm / min, and a strength-elongation curve at an elongation of 30% was drawn (see FIG. 7). E
Line), and then release the tension from the sample piece
An elongation curve was drawn (R line in FIG. 7). Then, the area (X) of the dotted line portion and the area (Y) of the hatched portion shown in FIG. 7 are measured,
It is obtained by the following formula. That is, the elongation recovery rate (%) at 30% elongation = 100Y / (X + Y). Further, the length of the nonwoven fabric refers to the arrangement direction of the machines at the time of manufacturing the nonwoven fabric, and the width of the nonwoven fabric refers to the direction orthogonal to the lengthwise direction. If the elongation recovery rate at 30% elongation is less than 20% in either the lengthwise direction or the widthwise direction of the nonwoven fabric, there is a tendency that sufficient stretchability cannot be obtained.

The stretchable long-fiber nonwoven fabric according to the present invention preferably has a compression stiffness of 80 g or less. The compression bending softness represents the flexibility of the nonwoven fabric, and the smaller the value of the compression bending softness, the more the flexibility. here,
The compression stiffness is measured by the following method. That is, a sample width of 50 mm is taken in the machine direction of the non-woven fabric (longitudinal direction of the non-woven fabric), and five sample pieces with a sample length of 100 mm are provided in the direction orthogonal to this direction. After bending in the direction to make a cylindrical shape and joining both ends to make a sample, Toyo Baldwin's Tensilon UTM-4-1-
Using 100, the sample was compressed in the sample width direction at a compression speed of 50 mm / min, the stress at the maximum load was measured, and the average value was taken as the compression stiffness. When the compression stiffness of the non-woven fabric exceeds 80 g, the flexibility of the non-woven fabric is lowered, and a feeling of coarseness and hardness tends to appear. The compression stiffness is preferably 50 g or less, and most preferably 30 g or less.

The elastic long-fiber nonwoven fabric according to the present invention preferably has an apparent density of 0.1 g / cm ³ or less.
The apparent density represents the bulkiness of the nonwoven fabric, and the smaller the value, the higher the bulkiness. Here, the apparent density is measured by the following method. That is,
Prepare 5 sample pieces with a sample width of 10 cm and a sample length of 10 cm, measure the basis weight (g / m ² ) for each sample piece, and then use the thickness measuring device manufactured by Daiei Kagaku Seiki Seisakusho to measure 4.5 g on each sample piece. / Cm ² load was applied, the thickness (t) after standing for 10 seconds was measured, the apparent density was calculated by the following formula, and the average value was used as the apparent density of the nonwoven fabric. Apparent density (g / cm ³ ) = [Unit weight (g
/ M ² ) / 1000 t (mm)]. Apparent density is 0.1g /
If it exceeds cm ³ , there is a tendency that sufficient bulkiness cannot be obtained.

The single fiber fineness of the long fibers a or A and the long fibers b or B used in the present invention is a matter which can be arbitrarily determined, but generally 6 denier or less is preferable. When the single fiber fineness exceeds 6 denier, the flexibility of the resulting long-fiber nonwoven fabric tends to decrease. In addition, it is preferable that the single fiber fineness of the long fiber a or A and the single fiber fineness of the long fiber b or B be different. In addition, for each long fiber, a matting agent, a light-proofing agent, which is used for general fibers,
Various chemicals such as a heat-resistant agent, a pigment, and a crystallization accelerator for a thermoplastic resin that functions during the production of long fibers may be added. The basis weight of the resulting long-fiber non-woven fabric is also a matter that can be arbitrarily determined, but generally it is about 150 g / m ² or less, but when it is desired to be particularly thick, it is about 500 g / m ² . It may be.

[0024]

EXAMPLES Next, the present invention will be specifically described based on Examples. In addition, regarding the measurement and evaluation of various characteristics in the examples, those described before were measured by the method, and those not described before were measured and evaluated by the following method. (1) Melt flow rate value: Measured by the method described in ASTM D1238 (L). (2) Melt index value: Measured by the method described in ASTM D1238 (E). (3) Tensile strength of long-fiber non-woven fabric: Tensilon UTM-4-1-100 manufactured by Toyo Baldwin Co., Ltd. was used, and 10 pieces of a sample with a sample width of 5 cm and a sample length of 10 cm were used according to the strip method described in JIS L-1096. The maximum tensile strength was individually measured under the condition that the tensile speed was 10 cm / min, and the average value was converted into a basis weight of 100 g / m ² . (4) Elongation of long-fiber nonwoven fabric: Elongation at maximum tensile strength measured by the method of (3). (5) Abrasion resistance of long-fiber non-woven fabric: The surface of the test piece was rubbed by using a Gakushin type abrasion resistance tester of JIS L-1084 A-1 in accordance with the 45R method of the same method. The test piece had a size of 14 cm × 5 cm, and five long-fiber nonwoven fabrics were used each in length and width.
On the other hand, as a 45R friction element, white cloth cotton cloth No. 3 for dyeing fastness specified in JIS L-0803 was used. Then, the test piece was rubbed 100 times at a reciprocating speed of 30 times per minute with a load of 200 gf, and the appearance change was observed and evaluated as follows. There is no change in appearance. The fibers on the surface of the 5th class long fiber non-woven fabric are slightly disturbed. The fibers on the 4th class long fiber non-woven fabric surface are slightly disturbed, but there is no problem. The fibers on the 3rd class long fiber non-woven fabric surface become slightly fluffy. There are 2nd class filaments The fibers on the surface of the non-woven fabric are pill-like 1st class

Example 1 As the low melting point component M ₂ , a melting point of 138 ° C., a melt flow rate value of 50 g / 10 minutes, and a Q value (weight average molecular weight / number average molecular weight)
A thermoplastic resin was prepared, which was 4.0 and had a polypropylene copolymer in which 4% by weight of ethylene was randomly copolymerized. On the other hand, as the high melting point components (M ₁ and M ₃ ), the melting point 162
A thermoplastic resin composed of a polypropylene-based polymer having a melt flow rate value of 70 g / 10 minutes and a Q value of 4.0 was prepared. Then, using a spinning device as shown in FIG. 5, the low melting point component is charged into an extruder type extruder and the high melting point component is charged into a separate extruder type extruder, and melting and weighing are performed. After that, the low melting point component and the high melting point component are separately introduced into the introduction path by using three melt composite spinning devices as shown in FIG. The melt composite spinning device has a spinning hole diameter of 0.5 m.
m, 72 parallel compound spinning holes, and spinning hole diameter 0.5 mm, number of holes
Equipped with 72 concentric core-sheath composite spinning holes, and with an intermediate plate which makes the ratio of the thermoplastic resin distributed between the parallel type composite spinning holes and the concentric sheath-type composite spinning holes 1: 1. .. Then, the single-hole discharge rate of the spinning holes is set to 1.25 g / min, respectively, and the weight ratio of the low-melting point component and the high-melting point component is set to 1: 1, and the melt composite spinning is performed at a spinning temperature of 220 ° C. I did. The spun filaments were drawn and pulled by 12 air suckers, and stretched to obtain parallel composite filaments a and concentric core-sheath composite filaments b. Then, the long fibers a and b were deposited on the moving collection conveyor to obtain a long fiber web. At this time, the long fiber web has a circular cross section as a whole, and the composite form is a parallel type latent crimpable composite long fiber a,
The non-latent crimping composite filaments b of concentric core-sheath type were uniformly mixed in an equal proportion.

The obtained long fiber web was introduced into an embossing device consisting of a smooth roll and a concavo-convex roll in which the ratio of the total area of the convex portions to the total surface area of the roll was 6%. The temperature of the uneven roll was 125 ° C., and the linear pressure between the uneven roll and the smooth roll was 30 kg / cm. By introducing the long fiber web into the embossing device, the long fibers a, the long fibers b, and the long fibers a and b are fused by the low melting point component in the area corresponding to the convex portion of the concavo-convex roll. A fused area was formed. At the same time, the heat of the concavo-convex roll was applied to the entire continuous fiber web 14, and the continuous fibers a were crimped. The parallel composite crimped filament A in the filament non-woven fabric thus obtained has a crimp number of 28/25 mm, and the concentric core-sheath composite filament B is substantially crimped. It had no shrinkage. The various physical properties of this long-fiber nonwoven fabric were as follows. Note Unit weight of long-fiber non-woven fabric 40 g / m ² Strength of long-fiber non-woven fabric 11.50 kg Elongation of long-fiber non-woven fabric 63% Long-fiber non-woven fabric 30% Elongation recovery rate during elongation 26% (longitudinal) 29% (horizontal) long-fiber non-woven fabric Apparent density of 0.054 g / cm ³ Compression stiffness of long-fiber nonwoven fabric 25 g Wear resistance of long-fiber nonwoven fabric Grade 5

Example 2 The long-fiber nonwoven fabric obtained in Example 1 was further introduced into a hot-air circulation type heat treatment machine and heat-treated in a relaxed state. The heat treatment conditions were a hot air temperature of 135 ° C. and a treatment time of 1 minute. The parallel composite crimped filament A in the filament non-woven fabric thus obtained has a crimp number of 40 pieces / 25 mm, and the concentric core / sheath composite filament B is 2 pieces / 25 mm. Had a number of crimps of. The various physical properties of this long-fiber nonwoven fabric were as follows. Note Weight of long-fiber non-woven fabric 47 g / m ² Strength of long-fiber non-woven fabric 8.30 kg Elongation of long-fiber non-woven fabric 65% Extension recovery rate of long-fiber non-woven fabric at 30% 45% (longitudinal) 46% (horizontal) long-fiber non-woven fabric Apparent density of 0.044 g / cm ³ Compression stiffness of long-fiber non-woven fabric 18 g Wear resistance of long-fiber non-woven fabric Class 4

Example 3 As the low melting point component M ₂ , a thermoplastic resin made of high density polyethylene having a melting point of 132 ° C. and a density of 0.96 g / cm ³ was prepared.
On the other hand, as the high melting point components (M ₁ and M ₃ ), a melting point of 258 ° C.,
Mixed solvent of equal amount of tetrachloroethane and phenol (20
A thermoplastic resin made of polyethylene terephthalate having a relative viscosity of 1.38 when dissolved in (° C.) Was prepared. Then, using a conventionally known spinning device, the low melting point component is charged into an extruder type extruder, and the high melting point component is charged into a separate extruder type extruder, and melting and weighing are performed. After that, the low melting point component and the high melting point component are separately introduced into the introduction path by using a melt composite spinning device as shown in FIG. The melt composite spinning device is provided with a parallel type composite spinning hole having a spinning hole diameter of 0.5 mm and a number of holes of 108, and a concentric core-sheath type composite spinning hole having a spinning hole diameter of 0.5 mm and a number of holes of 108. Then, the single-hole discharge rate of the spinning holes is set to 0.40 g / min, respectively, and the weight ratio of the low-melting point component and the high-melting point component is set to 1: 1, and the melt composite spinning is performed at the spinning temperature of 285 ° C. The filaments were collected and collected at a spinning speed of 400 m / min to obtain an undrawn yarn in which the parallel composite filaments and the concentric core-sheath composite filaments were mixed. This unstretched yarn,
Heat drawing was performed by the following method. That is, using a one-stage hot roller drawing machine, a drawing speed of 1200 m / min and a first roller temperature of 65
C., the second roller temperature was 85.degree. C., and the draw ratio was 3.0. The thus-obtained drawn yarn is pulled by an air sucker to be taken out, and is collided on a moving collecting conveyor to open the fiber, while the parallel composite long fiber a
And the concentric core-sheath composite type long fibers b were uniformly mixed and deposited. At this time, the single fiber fineness of the long fibers a and b was 3 denier. Further, the number of crimps of the long fiber a in the long fiber web was 2 pieces / 25 mm, and the crimp did not occur in the long fiber b.

The obtained continuous fiber web was introduced into the same embossing apparatus as in Example 1 except that the temperature of the concavo-convex roll was changed to 120 ° C. to provide the spot fusion zone. Then, the continuous fiber web provided with the spot fusion zone was introduced into the same heat treatment machine as in Example 2 except that the temperature of hot air was changed to 120 ° C.,
Heat treatment was performed. The parallel composite crimped filament A in the long fiber nonwoven fabric thus obtained has a crimp number of 71 pieces / 25 mm, and the concentric core-sheath composite filament B is 3 pieces / 25 mm. Had a number of crimps of. The various physical properties of this long-fiber nonwoven fabric were as follows. Note The unit weight of long-fiber non-woven fabric 58 g / m ² The strength of long-fiber non-woven fabric 10.60 kg The elongation of long-fiber non-woven fabric 63% The elongation recovery rate of long-fiber non-woven fabric 51% (longitudinal) 53% (horizontal) long-fiber non-woven fabric Apparent density of 0.035 g / cm ³ Compression stiffness of long-fiber nonwoven fabric 21 g Wear resistance of long-fiber nonwoven fabric Grade 5

Example 4 As the low melting point component M ₂ , a melting point of 132 ° C., a density of 0.96 g / cm ³ ,
A thermoplastic resin made of high-density polyethylene having a melt index value of 20 g / 10 minutes and a Q value of 2.44 was prepared. On the other hand, as a high melting point component (M ₁ and M ₃ ), a thermoplastic resin made of a polypropylene polymer having a melting point of 162 ° C., a melt flow rate value of 30 g / 10 minutes and a Q value of 4.5 was prepared. And
Using the spinning apparatus as shown in FIG. 5, the low melting point component is charged into the extruder type extruder, and the high melting point component is charged into the separate extruder type extruder, and melting and weighing are performed. After that, the low melting point component and the high melting point component are separately introduced into the introduction path by using a melt composite spinning device as shown in FIG.
The melt-composite spinning device is equipped with a parallel type composite spinning hole having a spinning hole diameter of 0.5 mm and a number of holes of 96, and a concentric core-sheath type composite spinning hole having a spinning hole diameter of 0.5 mm and a number of holes of 48, and a parallel type composite spinning hole. The ratio of the thermoplastic resin distributed to the concentric core-sheath type composite spinning hole is 2: 1
It has an intermediate plate. Then, the single-hole discharge rate of the spinning holes is set to 1.25 g / min, respectively, and the weight ratio of the low-melting point component and the high-melting point component is set to 1: 1, and the melt composite spinning is performed at a spinning temperature of 240 ° C. I did. The spun filaments were drawn while being pulled by an air sucker, and stretched to obtain parallel composite filaments a and concentric core-sheath composite filaments b. Subsequently, forcible opening was performed by corona discharge to deposit the long fibers a and b on the moving collection conveyor to obtain a long fiber web. At this time, the long fiber web has a circular cross section as a whole, a composite form is a parallel type, and a latent crimpable composite long fiber a having a crimp number of 2 pieces / 25 mm and a composite form is a concentric sheath type. The non-latent crimping composite filament b was uniformly mixed at a ratio of 2: 1.

The obtained long fiber web was introduced into an embossing device comprising a concavo-convex roll having a total area of the convex portions of 4% with respect to the total surface area of the roll and a smooth roll. The temperature of the uneven roll was 120 ° C., and the linear pressure between the uneven roll and the smooth roll was 30 kg / cm. By introducing the long fiber web into the embossing device, the long fibers a, the long fibers b, and the long fibers a and b are fused by the low melting point component in the area corresponding to the convex portion of the concavo-convex roll. A fused area was formed. Then, the filament was introduced into the heat treatment machine in the same manner as in Example 3 to cause the filament a to develop crimps. The parallel composite crimped filament A in the filament non-woven fabric thus obtained has a crimp number of 42/25 mm, and the concentric core-sheath composite filament B is 1/25 mm. Had a number of crimps of. The various physical properties of this long-fiber nonwoven fabric were as follows. Note The basis weight of long-fiber non-woven fabric 53 g / m ² The strength of long-fiber non-woven fabric 8.50 kg The elongation of long-fiber non-woven fabric 73% The elongation recovery rate of long-fiber non-woven fabric 41% when expanded 41% (longitudinal) 43% (horizontal) long-fiber non-woven fabric Apparent density of 0.040 g / cm ³ Compression stiffness of long fiber non-woven fabric 13 g Wear resistance of long fiber non-woven fabric Class 4

Comparative Example 1 Using the low melting point component and the high melting point component used in Example 4, melt spinning was performed using a parallel type composite melt spinning apparatus. This parallel type composite melt spinning device has a spinning hole diameter of 0.5 m.
Only the parallel type composite spinning holes having m and the number of holes of 144 are provided. Melt composite spinning was performed at a spinning temperature of 240 ° C. with a single hole discharge rate of 1.25 g / min and a weight ratio of the low melting point component and the high melting point component of 1: 1. Then, a continuous fiber web was obtained in the same manner as in Example 4. This long fiber web was composed only of side-by-side composite long fibers. Then, spot fusion zones were provided by the same method as in Example 4, and heat treatment was performed by the same method to obtain a nonwoven fabric. The number of parallel composite crimped filaments in this nonwoven fabric is 42 /
It had a crimp number of 25 mm. The various physical properties of this non-woven fabric were as follows. Note Nonwoven fabric weight 58 g / m ² Nonwoven fabric strength 3.20 kg Nonwoven fabric elongation 121% Nonwoven fabric 30% Elongation recovery rate when stretched 48% (length) 51% (width) Nonwoven fabric apparent density 0.053 g / cm ³ Compressive stiffness and softness 11g Non-woven fabric abrasion resistance class 2 As can be seen by comparing the long fiber non-woven fabric obtained in Example 4 with the non-woven fabric obtained in Comparative Example 1, the non-woven fabric according to Comparative Example 1 However, it has a large expansion / contraction rate. That is, it is understood that the non-crimped long fibers may be mixed in the nonwoven fabric in order to reduce the stretchability of the nonwoven fabric composed only of the crimped long fibers to some extent.

Example 5 As the low melting point component M ₂ , a melting point of 132 ° C., a density of 0.95 g / cm ³ ,
A thermoplastic resin made of high-density polyethylene having a melt index value of 20 g / 10 minutes and a Q value of 2.44 was prepared. On the other hand, as a high melting point component (M ₁ and M ₃ ), a thermoplastic resin made of a polypropylene polymer having a melting point of 162 ° C., a melt flow rate value of 68 g / 10 minutes and a Q value of 3.85 was prepared. And
Using the spinning apparatus as shown in FIG. 5, the low melting point component is charged into the extruder type extruder, and the high melting point component is charged into the separate extruder type extruder, and melting and weighing are performed. After that, the low melting point component and the high melting point component are separately introduced into the introduction path by using a melt composite spinning device as shown in FIG.
The melt composite spinning device is equipped with a parallel type composite spinning hole having a spinning hole diameter of 0.5 mm and a number of 72 holes, and a concentric core-sheath type composite spinning hole having a spinning hole diameter of 0.5 mm and a number of 72 holes, and a parallel type composite spinning hole. The ratio of the thermoplastic resin distributed to the concentric core-sheath type composite spinning hole is 1: 1
It has an intermediate plate. Then, the single-hole discharge rate of the spinning holes is set to 1.25 g / min, respectively, and the weight ratio of the low-melting point component and the high-melting point component is set to 1: 1, and the melt composite spinning is performed at a spinning temperature of 240 ° C. I did. The spun filaments were drawn while being pulled by an air sucker, and stretched to obtain parallel composite filaments a and concentric core-sheath composite filaments b. Subsequently, these long fibers were deposited on a moving collection conveyor to obtain a long fiber web. At this time, the long fiber web has a circular cross section as a whole, a composite form is a parallel type, and a latent crimpable composite long fiber a having a crimp number of 2 pieces / 25 mm and a composite form is a concentric sheath type. The non-latent crimping composite filament b is
It was uniformly mixed at a ratio of 1: 1. Then, this long fiber web was introduced into an embossing device by the same method and conditions as in Example 1 except that the temperature of the concavo-convex roll was set to 120 ° C., and a spot fusion zone was provided. The parallel composite crimped filaments A in the filament nonwoven fabric thus obtained have a crimp number of 18/25 mm, and the concentric core-sheath conjugate filament B is substantially crimped. It had no shrinkage.

Example 6 Using the long fiber non-woven fabric obtained in Example 1, the temperature of hot air was changed.
Heat treatment was performed by introducing the same into the same heat treatment machine as in Example 2 except that the temperature was changed to 140 ° C. The various physical properties of the obtained long-fiber nonwoven fabric were as follows. Note Unit weight of long-fiber non-woven fabric 63 g / m ² Strength of long-fiber non-woven fabric 11.55 kg Elongation of long-fiber non-woven fabric 58% Expansion recovery rate of long-fiber non-woven fabric 21% (longitudinal) 22% (horizontal) long-fiber non-woven fabric Apparent density of 0.125 g / cm ³ Compression stiffness of long-fiber non-woven fabric 95 g Wear resistance of long-fiber non-woven fabric Class 5

Examples 7 to 10 Table 1 shows the numbers of parallel type composite spinning holes and concentric core-sheath type composite spinning holes using the same low melting point component and high melting point component as those used in Example 3. A long fiber non-woven fabric was obtained under the same conditions as in Example 3 except for the above changes. In the intermediate plate for distributing the thermoplastic resin (low melting point component and high melting point component) between the parallel type composite spinning hole and the concentric core-sheath type composite spinning hole,
The distribution ratio was changed depending on the number of parallel type composite spinning holes and the number of concentric core-sheath type composite spinning holes. Table 1 also shows various physical properties of the long-fiber nonwoven fabric obtained as described above.

[Table 1] As is clear from Table 1, the long fiber nonwoven fabrics according to Examples 7 to 10 all have good stretchability and tensile strength. In addition, as a general tendency, when the parallel composite filament a or A increases and the concentric core / sheath composite filament b or B decreases, the elongation recovery rate tends to increase, and conversely, the concentric sheath composite. When the type filaments b or B increase and the parallel composite type filaments a or A decrease, the elongation recovery rate tends to decrease.

[0036]

As described above, according to the present invention, the latent crimpable composite filaments a and the non-latent crimpable composite filaments b having different composite forms are uniformly mixed. The fibrous web is subjected to a point fusion zone and, at the same time or thereafter, the long fibers a are crimped to obtain a stretchable long fiber nonwoven fabric. Since the same low melting point component is exposed on the fiber surface in the long fibers a and b, the long fibers are fused by the low melting point component. The high-melting-point component retains the fiber form in the area other than the spot fusion area, and therefore has the effect of preventing the tensile strength of the resulting stretchable long-fiber nonwoven fabric from decreasing. Also,
In the long-fiber nonwoven fabric thus obtained, the long fibers A are crimped, and the long fibers A are not fusion-fixed in the areas other than the spot-fusion area. Therefore, the long fibers A in the area other than the spot fusion area freely expand and contract, while the long fibers B do not exhibit crimp, so that the movement of the long fibers A is slightly suppressed. As a result, by mixing the long fibers B in a predetermined ratio, it is possible to impart the desired stretchability to the obtained long fiber nonwoven fabric. Therefore, the long-fiber non-woven fabric according to the present invention is suitable for various applications such as clothing, industrial materials, civil engineering and construction, agricultural and horticultural materials, life-related materials, medical hygiene materials, etc. is there.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a cross section of a non-latent crimpable concentric sheath-core filament b.

FIG. 2 is a schematic view showing an example of a cross section of a latent crimpable parallel filament a.

FIG. 3 is a schematic view showing an example of a cross section of a non-latent crimpable concentric sheath-core filament b.

FIG. 4 is a schematic diagram showing an example of a cross section of a latent crimpable parallel filament a.

FIG. 5 is a schematic view showing an apparatus for producing a stretchable long-fiber nonwoven fabric according to an example of the present invention.

FIG. 6 is a cross-sectional view showing an example of a melt-composite spinning apparatus used to discharge latently crimpable composite long fibers a and non-latent crimpable composite long fibers b.

FIG. 7 is a strength-elongation curve for explaining the definition of elongation recovery rate at 30% elongation.

[Explanation of symbols]

 14 Long Fiber Web 17 Heat Treatment Device 20 Stretchable Long Fiber Nonwoven Fabric

Claims (7)

[Claims] 1. A composite long fiber A composed of a high melting point component M ₁ and a low melting point component M ₂ , a high melting point component M ₃ and a low melting point component M ₂ and the long fiber A. The long fibers A are obtained by uniformly mixing the composite long fibers B having different composite forms.
Has a crimp but the filament B has substantially no crimp, and the low melting point component M ₂ of the filaments A and B is the filament A.
And B are arranged so as to be exposed on at least the surface, and the low melting point component M ₂ of the long fibers A and B causes fusion between the long fibers A, between the long fibers B, and between the long fibers A and B. A stretchable long-fiber non-woven fabric having a point fusion zone. 2. The elongation recovery rate at 30% elongation is 20% in both length and width.
The stretchable long-fiber non-woven fabric according to claim 1, having a compression stiffness of 80 g or less and an apparent density of 0.1 g / cm ³ or less. 3. The stretchable long-fiber nonwoven fabric according to claim 1, wherein the composite form of the long fibers A is a side-by-side composite form, and the composite form of the long fibers B is a concentric core-sheath composite form. 4. The stretchable long-fiber non-woven fabric according to claim 1, wherein 20 to 80 parts by weight of the continuous fiber A and 80 to 20 parts by weight of the continuous fiber B are uniformly mixed. 5. A latent crimpable composite filament a, which is obtained by melt-compositing a high-melting point component M ₁ and a low-melting point component M ₂ and in which the low-melting point component M ₂ is exposed at least on the surface thereof. Obtained by melt-compositing a high-melting point component M ₃ and a low-melting point component M ₂ , the low-melting point component M ₂ is exposed at least on the surface thereof, and the non-latent winding having a composite form different from that of the long fiber a. The shrinkable composite type continuous fiber b is uniformly mixed to obtain a continuous fiber web, and the continuous fiber web is partially heated and optionally pressed to obtain the low melting point component M ₂ of the continuous fibers a and b. A point fusion zone is formed by melting and fusing between the long fibers a, between the long fibers b, and between the long fibers a and b, and at the same time as or after providing the point fusion area, the entire long fiber web is heat treated. Then, the method for producing a stretchable long-fiber nonwoven fabric is characterized in that the long-fiber a is crimped. 6. 30 to 70 parts by weight of a high melting point component M ₁ and 70 to 30
By melt-compounding with parts by weight of the low-melting point component M ₂ to obtain latent crimpable composite long fibers a, 30 to 70 parts by weight of the high-melting point component M ₃ are obtained.
And 70 to 30 parts by weight of the low-melting point component M ₃ are subjected to melt-composite spinning to obtain a non-latent crimping composite long fiber b, and 20 to 80 parts by weight of long fiber a and 80 to 20 parts by weight of long fiber. The method for producing a stretchable long-fiber nonwoven fabric according to claim 5, wherein b and b are uniformly mixed. 7. The composite form of the latently crimpable composite long fibers a is a parallel composite form, and the composite form of the latently crimpable composite long fibers b is a concentric core-sheath composite form. A method for producing the elastic long-fiber nonwoven fabric described.