JPH1088456A - Elastic nonwoven fabric of filament and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain nonwoven fabric improved in fiber uniformity and excellent in stretchability. SOLUTION: This nonwoven fabric comprises accumulated crimped filaments. The crimped filaments are obtained by crimping and developing latently crimpable filaments. The latently crimpable filaments are composed of a fiber- forming polymer A and a fiber-forming polymer B having a heat shrinkage percentage higher than that of the polymer A in a combined state in which the polymer B is exposed to at least a part of the surface. Zones in which the crimped filaments are mutually fused by the softening or melting of the having B are laid in a scattered state in the nonwoven fabric. The nonwoven fabric simultaneously satisfies conditions of (i) the elongation at break of the nonwoven fabric in the width direction is >=150%, (ii) the ratio of the elongation at break of the nonwoven fabric in the longitudinal direction to that in the width direction is >=5, (iii) the elongation recovery ratio when the nonwoven fabric is elongated at 50% in the width direction is 160% and (iv) the elongation recovery ratio of the nonwoven fabric in the width direction when elongated at 100% is >50%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a long-fiber nonwoven fabric having excellent elasticity and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, nonwoven fabrics have been used for various purposes such as clothing, industrial materials, civil engineering materials, agricultural and horticultural materials, living related materials, and medical hygiene materials. Among them, in particular, nonwoven fabrics used for medical hygiene materials such as surface materials of disposable diapers, base cloth of puppet materials, sports supporters or bandages, etc., are easy to follow the movement of the human body and easily adapt to the human body. For this reason, elasticity is required. In order to impart elasticity to a nonwoven fabric, a method of using crimped fibers having good elasticity as a fiber constituting the nonwoven fabric, or a method of using a polyurethane fiber or the like having a material itself having elasticity is known. ing.

[0003] As the technology belonging to the former, the following are mentioned. For example, JP-A-63-28960 discloses a stretchable nonwoven fabric obtained by subjecting a latently crimpable short fiber web to a hydroentanglement and then performing a heat treatment to make the latently crimp visible. JP-A-2-91217 discloses that
After performing needle punch on the latently crimpable short fiber web,
A stretchable nonwoven fabric that has been subjected to heat treatment to make latent crimps visible is disclosed. In Japanese Patent Publication No. 4-46145, in the spinning process, a spun yarn having an irregular cross section is subjected to single-side cooling to impart a cooling strain, and utilizing this strain, a manifest or latent crimp is converted into a long fiber. A stretchable nonwoven fabric which is provided with the long fibers as constituent fibers is disclosed. Tokiwa 4-46
No. 147 discloses two kinds of polymers having different heat shrinkages,
A stretchable nonwoven fabric has been disclosed in which a fibrous web formed by accumulating conjugate long fibers composited in a side-by-side or eccentric core-sheath type is subjected to a heat treatment so that the long fibers exhibit crimps with different heat shrinkages. The technology belonging to the latter is disclosed in
Japanese Patent Application Laid-Open No. 9-223347 discloses a stretchable nonwoven fabric using thermoplastic polyurethane elastic fibers as constituent fibers.

However, the stretchable nonwoven fabric obtained by the technique belonging to the former has a drawback that the formation is poor (the fiber density on the surface of the nonwoven fabric is extremely high and low) and the degree of stretchability is low. The reason for these drawbacks is that
It is as follows. A fiber aggregate formed by randomly accumulating latently crimpable short fibers or long fibers originally has an area where the intersections of the fibers are dense and an area where the intersections of the fibers are not dense. And has a certain degree of fiber density. In such a fiber aggregate, when a crimp is developed in the latent crimpable fiber, in the area where the intersections of the fibers are dense, the fibers are hard to move, while the intersections of the fibers are not dense. In the area, each fiber is relatively mobile. Therefore, when crimps appear,
The fibers in the easy-to-move areas gather toward the hard-to-move areas, and the areas where the fiber density was originally denser become denser,
Conversely, the area where the fiber density is coarser becomes coarser, and the resulting elastic nonwoven fabric has a remarkably dense and dense structure, so that only a poorly formed one can be obtained. In addition, this stretchable nonwoven fabric only exhibits the stretchability due to the expansion and contraction of the crimped fibers and cannot exhibit the stretchability due to the structure of the nonwoven fabric such as the fiber arrangement. It was low. In addition, the stretchable nonwoven fabric obtained by the technology belonging to the latter has a regret that it cannot be used for general-purpose applications in terms of weather resistance and odor because the fiber material is limited to polyurethane.

On the other hand, the following stretchable nonwoven fabrics are known as those exhibiting stretchability due to the nonwoven fabric structure. That is, mainly obtained by the melt blown method,
The fiber web in which the constituent fibers are randomly arranged is partially subjected to heat fusion to obtain a fiber fleece in which the heat fusion areas are scattered, and thereafter, the fiber fleece is subjected to heat drawing. There is known a method of producing a nonwoven fabric in which the constituent fibers are arranged so as to be arranged in the longitudinal direction and stretched in the width direction (US Pat. No. 5,244,482).

However, since the constituent fibers used here are fibers composed of a single component, when the constituent fibers are heat-sealed to each other, the fiber form collapses at the fused portion, and the breaking strength (tensile strength) is reduced. In some cases, it was difficult to obtain a stretchable nonwoven fabric having a large size. Further, in order to obtain the constituent fibers by the melt blown method, only constituent fibers having a small fiber diameter (small fineness) were obtained, which also made it difficult to obtain an elastic nonwoven fabric having a large breaking strength. In addition, the nonwoven fabric obtained by this method has good stretchability in the width direction, but the size of the gap between the constituent fibers is reduced,
High fiber density (low porosity). That is, according to US Pat. No. 5,244,482, the size of the gap between the constituent fibers in the obtained stretchable nonwoven fabric is 80% of the size of the gap between the constituent fibers in the fiber fleece. It is described as follows. Depending on the use of the stretchable nonwoven fabric, such a decrease in voids, that is, a decrease in porosity, and a low breaking strength may be acceptable. For example, it can be used as a filtering material for filtering fine dust. However, when used for medical applications such as surface materials for disposable diapers applied to the human body, backing cloth for puppets, supporters for sports, bandages, etc., the decrease in porosity and low tensile strength are not expected. Gives undesired results.
That is, since a stretchable nonwoven fabric having a small porosity has low air permeability, when it is used as a sports supporter or the like, there is a drawback that sweaty sweat easily occurs and gives a user discomfort. In addition, since the liquid permeability is low, when used as a surface material of a disposable diaper, there is a drawback that a bodily fluid hardly permeates into an absorbent body of the disposable diaper body, and the bodily fluid leaks. Further, if the breaking strength is low, there is a drawback that the film breaks during use.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a method for producing a stretchable non-woven fabric using latently crimpable fibers, namely, the disadvantages of poor non-woven fabric formation and the degree of stretchability of the non-woven fabric. While eliminating the disadvantages caused by the method of obtaining a stretchable non-woven fabric by rearranging the constituent fibers, that is, reducing the breaking strength of the non-woven fabric and reducing the porosity of the non-woven fabric. It was made for the purpose. That is, an object of the present invention is to solve various drawbacks of a stretchable nonwoven fabric manufactured by a conventional technique at once.

[0008] The basic technical idea of the present invention is to use a specific composite form as a latently crimpable fiber to be used as a heat-adhesive fiber and to completely change the fiber form. The point of providing a heat-sealing area without collapsing to prevent a decrease in the breaking strength of the nonwoven fabric, and the number of intersections between latently crimpable filaments caused by random accumulation are considered as Due to the arrangement, the number of the intersections is reduced and then the crimp is developed to prevent the formation of the nonwoven fabric from deteriorating. The point is that the property is imparted to the nonwoven fabric and that the latently crimpable fibers are crimped to increase the voids (gaps) between the fibers, thereby preventing a decrease in the porosity.

The present invention provides a method for obtaining a stretchable nonwoven fabric using latently crimpable fibers (the technique described in Japanese Patent Publication No. 46147/1992) and a method for obtaining a stretchable nonwoven fabric by changing the arrangement of constituent fibers ( It is not merely a combination with U.S. Pat. No. 5,244,482. This will be clear from the description of the basic technical idea described above. That is, the latently crimpable fiber is used not only for simply exhibiting elasticity, but also for preventing a decrease in the breaking strength of the obtained nonwoven fabric and for preventing a decrease in the porosity of the obtained nonwoven fabric. Being used, also about the arrangement change of the constituent fibers, not only to exhibit the elasticity, but also to reduce the number of intersections between the fibers, the non-woven fabric with the crimp expression of latently crimpable long fibers It is clear from the fact that it is used to prevent formation deterioration, and such a technical idea is a new idea that did not exist in the prior art.

Further, since the present invention is based on the above-mentioned basic technical concept, it will be apparent that the present invention is different from the following prior art. In order to avoid duplication, a brief description is as follows. To a fiber fleece with a heat fusion area formed by a general spunbond method,
As a method for imparting heat stretching, Japanese Patent Publication No. 57-5458
No. 3 and Japanese Patent Application Laid-Open No. 2-33369 are known, but they are crucially different in that they do not aim at exhibiting elasticity as in the present invention. That is, the former technique aims at obtaining a nonwoven fabric having a good feel and excellent drapability, and a method of partially cutting constituent fibers by applying heat drawing to a fiber fleece. is there. In addition, the latter technique aims at obtaining a nonwoven fabric having less fuzz, excellent tensile strength and elongation properties and excellent feeling, and uses a low crystallinity and low orientation unstretched long fiber to form a fiber fleece. By forming and subjecting the fiber fleece to hot drawing, the undrawn long fibers are converted into highly crystalline and highly oriented long fibers. In other words, the technique is to convert the fibers in the fiber fleece into long fibers having good physical properties after obtaining the fiber fleece. Further, in the former two techniques, since non-composite long fibers each composed of a single component are used, it is difficult to control the temperature of heat fusion at the time of forming a fiber fleece. That is, if the temperature at the time of heat fusion is high, the long fiber form is completely collapsed in the heat fusion area, and a hole is opened or cut by thermal stretching. On the other hand, if the temperature at the time of heat fusion is low, the fusion is incomplete, and the nonwoven fabric itself collapses at the time of hot stretching.

According to the present invention, a fiber fleece is subjected to hot stretching similarly to the former two techniques. However, the object of the present invention is to obtain a nonwoven fabric having excellent stretchability. Is different in that the effect of reducing the intersections between the fibers in hot drawing is obtained, and that the fibers are crimped after the hot drawing.

[0012]

According to the present invention, the fiber-forming polymer A and the fiber-forming polymer B having a higher heat shrinkage than the polymer A are at least composed of the polymer A. A latently crimpable long fiber composited in a form exposed on a part of the surface is formed by accumulating crimped long fibers obtained by expressing a crimp, and the space between the crimped long fibers is the polymer B. An elastic long-fiber nonwoven fabric in which a fusion zone fused by softening or melting is provided in a scattered manner, and the nonwoven fabric has a breaking elongation in a width direction (also referred to as a lateral direction) of 150% or more. The ratio of the elongation at break in the width direction to the elongation at break in the longitudinal direction (also called the machine direction) is 5 or more, and the elongation recovery rate when the nonwoven fabric is stretched by 50% in the width direction is 60. % Or more, and the elongation recovery rate at 100% elongation in the width direction is 5%.
The present invention relates to a stretchable long-fiber nonwoven fabric characterized by being at least 0%.

The present invention also provides a fiber-forming polymer A,
Fiber-forming polymer B having a higher heat shrinkage than polymer A
And depositing the latently crimpable filaments composed of the polymer B in a form exposed on at least a part of the surface thereof on a collection conveyor to form a fibrous web, and partially forming the fibrous web. To obtain a fiber fleece in which a fusion zone in which the latently crimpable filaments are fused by softening or melting of the polymer B is provided in the fiber web in a scattered manner. Then, the fiber fleece is expanded in the width direction so as to have a width expansion ratio of 0 to 50%.
A stretchable long-fiber nonwoven fabric characterized in that the latent stretchable long-fiber non-woven fabric is heat-stretched at a draw ratio of up to 80%, and then heat-treated at a temperature equal to or lower than the melting point of the polymer B, so that the latently crimpable long-fiber is developed And a method for producing the same.

The stretchable long-fiber nonwoven fabric according to the present invention comprises crimped long fibers as constituent fibers. However, the present invention is not limited to one comprising 100% by weight of crimped long fibers, and other long fibers or short fibers may be mixed in the nonwoven fabric in a small amount. The crimped long fiber is obtained by applying heat to the latently crimpable long fiber to express the crimp. The latently crimpable long fiber is a composite of a fiber-forming polymer A and a fiber-forming polymer B having a higher heat shrinkage than the polymer A in a specific form. For example, a polymer A is used as a core component and a polymer B
As a sheath component to form an eccentric core-sheath composite. Polymer A
When heat is applied to this eccentric core-sheath type composite continuous fiber, the polymer B has a large heat shrinkage.
Is inside, and a spiral crimp is developed. Therefore, in the case of the concentric core-sheath type composite fiber, even if the heat shrinkage rates of the core component and the sheath component are different, the crimp does not appear because the cross section of the fiber is the object. Therefore, the concentric core-sheath type composite fiber is not a latently crimpable fiber and cannot be used in the present invention. Further, a polymer A having a half-moon cross section
In the case of a parallel type (side-by-side type) composite long fiber having a substantially circular cross section in which the polymer B and the polymer B are joined together, when heat is applied, the polymer B having a large heat shrinkage ratio is on the inner side, and crimps are developed. I do. In the present invention, not only the above-mentioned eccentric core-sheath type or side-by-side type composite long fiber but also any other material can be used as long as it gives rise to crimp when heat is applied.

The latently crimpable filaments used in the present invention are not only composed of the polymer A and the polymer B so as to simply cause the appearance of crimping, but also include at least the polymer B having a large heat shrinkage. It must be exposed on a part of the fiber surface. This is because, in the present invention, the latently crimpable long fibers also function as heat-adhesive fibers. That is, the polymer B having a large heat shrinkage has a softening point lower than that of the polymer A, and gives heat to the polymer B exposed on at least a part of the surface of the latently crimpable long fiber, whereby the polymer B is heated. The polymer B is softened or melted so that the latently crimpable long fibers are fused together. When the eccentric core-sheath type composite filament is used as the latently crimpable filament, the core component is not exposed on the fiber surface,
Polymer B cannot be used as the core component, and polymer A must be employed. In the case of side-by-side composite long fibers, since both polymers are exposed on the fiber surface, both polymers can be used arbitrarily without any particular limitation.
The latently crimped filaments or the crimped filaments are fused together by the softening or melting of the polymer B. At this time, the polymer A also softens or melts to some extent, and this fusion is performed. In some cases.

It is necessary to use polymers A and B having different heat shrinkage rates. The heat shrinkage is the rate at which the polymers A and B shrink when the latently crimpable filaments are placed in a constant temperature atmosphere. In general, the polymer B having a large heat shrinkage has a lower softening point or melting point than the polymer A having a small heat shrinkage. When the polymers A and B are the same polymer, the polymer B having a large heat shrinkage
Generally has a large intrinsic viscosity “η”. Therefore, in the present invention, it is often sufficient to employ polymers A and B having different melting points or softening points, or in the case of the same polymer, polymers A and B having different intrinsic viscosities.

For example, when polyethylene terephthalate is used as the polymers A and B, polyethylene terephthalate having a low intrinsic viscosity is used as the polymer A, and the one having a higher intrinsic viscosity is used as the polymer B. When polyethylene terephthalate is used as the polymer A, the main repeating unit of the polymer B is ethylene terephthalate (generally, 85 mol% or more is preferably ethylene terephthalate), and some acids are used. A copolymerized polyester obtained by copolymerizing a component and a glycol component may be employed. The copolymerized polyester has a lower melting point than polyethylene terephthalate and a large heat shrinkage. Further, as the polymer A, a high melting point copolymerized polyester is adopted, and as the polymer B, a low melting point copolymer obtained by copolymerizing a large amount of an acid component or a glycol component (for example, an acid component or a glycol component of 15 mol% or more). Polymerized polyester may be employed. In this case, the polymer B having a higher copolymerization ratio of the acid component and the glycol component has a lower melting point and a higher heat shrinkage. Isophthalic acid, adipic acid, or the like can be used as the acid component as the above-mentioned copolymer component. In addition, propylene glycol, diethylene glycol, or the like can be used as the glycol component.

When polypropylene is used as the polymer A, polyethylene may be used as the polymer B. In the same manner as above, as the polymer A / polymer B, polypropylene / modified polypropylene, polyethylene / modified polyethylene, polyethylene / ethylene-vinyl acetate copolymer, polyamide / modified polyamide, nylon 66 / nylon 6, nylon 66 / Any combination, such as nylon 610, can be employed.

Various additives such as a matting agent, a pigment, a light stabilizer, a heat stabilizer, an antioxidant, and a crystallization accelerator may be added to the polymer A or the polymer B, if necessary. May be added in a range that does not impair the purpose.

The fineness of the latently crimpable filaments is preferably 15 deniers or less. Therefore, it is generally preferable that the fineness of the crimped long fiber in which the latently crimpable long fiber is expressed is not more than 15 denier. If the fineness exceeds 15 denier, the rigidity of the long fibers increases, and the elasticity of the stretchable long-fiber nonwoven fabric increases, making it difficult to use for general-purpose applications. Further, when the fineness of the latently crimpable filaments exceeds 15 denier, in the melt spinning step which is a process of producing the latently crimpable filaments, there is a problem in cooling and solidifying the spun yarn,
In the drawing step of the fiber fleece, the operability tends to be inferior.

Further, the composite weight ratio of the polymer A and the polymer B in the latently crimpable long fiber is 1 part by weight of the polymer A
Is preferably 0.1 to 5 parts by weight, and most preferably 0.2 to 4 parts by weight.
When the composite weight ratio of the polymer A and the polymer B is out of the above range, depending on the types of the materials of the polymers A and B, good crimping may not be realized.

In the stretchable long-fiber nonwoven fabric according to the present invention,
There are a large number of scattered spots where the crimped long fibers are fused to each other. In this fusion zone, the crimped long fibers are fused to each other by softening or melting of the polymer B, and the polymer A does not soften or melt, or softens or melts to a certain extent to contribute to the fusion. However, it exists while maintaining the fiber form to some extent. The shape of each fusion zone is round, oval, diamond, triangle, T, well,
Although an arbitrary form such as a rectangle is adopted, the form is not clear, but somewhat obscure. This is because the form is distorted by the hot stretching. Further, the size of each fused area is preferably about 0.2 to 6.0 mm ² . Furthermore, the distance between adjacent fusion zones is about 0.3 to 2 mm at a short place, and 1 to 10 m at a long place.
m. Further, the total area of the fusion zone is preferably about 2 to 50% with respect to the surface area of the nonwoven fabric, and particularly preferably 5 to 25%.
%.

The stretchable long-fiber nonwoven fabric having the above-described structure has specific physical properties and satisfies the following four conditions simultaneously. First, the elongation at break in the width direction of the nonwoven fabric must be 150% or more. If the breaking elongation is less than 150%, the stretchability of the nonwoven fabric in the width direction is insufficient, and good stretchability cannot be exhibited. Second, the ratio of the breaking elongation in the width direction of the nonwoven fabric to the breaking elongation in the longitudinal direction of the nonwoven fabric must be 5 or more. That is, the extensibility in the width direction derived from the nonwoven fabric structure is relatively high. When the ratio is less than 5, the extensibility derived from the nonwoven fabric structure is not significantly higher than the extensibility derived from the crimp of the crimped long fiber, and the degree of elasticity due to the crimping is reduced. Thus, the object of the present invention, which is to impart superior elasticity to the nonwoven fabric, cannot be achieved. The breaking elongation (%) is measured according to the method described in JIS-L-1096A. That is, ten strip-shaped sample pieces each having a sample width of 5 cm were prepared, and a constant-speed elongation type tensile tester (Tensilon UTM-4-1-10 manufactured by Toyo Baldwin Co., Ltd.) was used.
Using (0), each sample piece was elongated at a distance between the chucks of 5 cm and a tensile speed of 10 cm / min, and the average elongation when each sample piece was broken was defined as the elongation at break (%). Therefore, the elongation at break (%) = ｛[(distance between chucks at break) − (5)] /
(5) It is calculated by｝ × 100. When the elongation at break in the width direction of the nonwoven fabric is measured, the elongation of the strip-shaped sample is measured so that the longitudinal direction is the width direction of the nonwoven fabric, and the elongation at break in the longitudinal direction of the nonwoven fabric is measured. In this case, it is needless to say that the measurement is performed by elongating the strip-shaped sample piece so that the longitudinal direction of the strip is the longitudinal direction of the nonwoven fabric.

Third, the elongation recovery rate when the nonwoven fabric is stretched by 50% in the width direction must be 60% or more. If the elongation recovery rate is less than 60%, the nonwoven fabric is stretched in the width direction by applying an external force, and then the shrinkage when the external force is released is insufficient and does not exhibit excellent elasticity.
Fourth, the elongation recovery rate when the nonwoven fabric is stretched 100% in the width direction must be 50% or more. Even when the elongation recovery rate is less than 50%, excellent stretchability is not exhibited. This elongation recovery rate is JIS-L-1096
It is measured by the following method according to the method described in 6.13.1A. First, five strip-shaped sample pieces each having a sample width of 5 cm are prepared. At this time, the longitudinal direction of the strip-shaped sample piece is set to be the width direction of the nonwoven fabric. Then, a constant speed elongation type tensile tester (Tensilon U manufactured by Toyo Baldwin Co., Ltd.)
Using TM-4-1-100), the distance between chucks is 5c.
m, at a pulling speed of 10 cm / min, each sample is stretched in the longitudinal direction (ie, in the width direction of the nonwoven fabric), and when the elongation rate becomes 50% (when the distance between the chucks becomes 5 × 1.5 cm) ) Or 100% (the distance between chucks is 5 ×
At 2 cm), the pulling is stopped. Thereafter, each sample piece was removed from the tensile tester and allowed to stand, and the distance between chucks of each sample piece after contraction of each sample piece was Lcm.
Is measured. The extension recovery rate (%) at the time of 50% extension is [(5 × 1.5−L) / (5 × 1.5−
5)] × 100. The extension recovery rate (%) at 100% elongation is [(5 × 2-L) / (5 × 2
-5)] × 100.

The porosity of the stretchable long-fiber nonwoven fabric according to the present invention is preferably 85% or more, and most preferably 90% or more. The present invention makes it possible to obtain a stretchable long-fiber nonwoven fabric without substantially reducing the porosity. For example, a fiber fleece (a fiber aggregate as a precursor for obtaining a stretchable long-fiber nonwoven fabric) can be obtained. Even if the porosity is less than 85%, the obtained stretchable long-fiber nonwoven fabric has a porosity of 85% or more. If the porosity of the stretchable long-fiber nonwoven fabric is less than 85%, the size of the voids formed between long fibers is too small, and tends to be unsuitable for general use. For example, when a stretchable long-fiber nonwoven fabric is used as a medical hygiene material, sweat and the like tend to accumulate and become humid, or tend to have poor body fluid permeability. The porosity (%) of the stretchable long-fiber nonwoven fabric is [1- (w / tSρ)] × 100.
(%). Here, S represents the area (cm ² ) of the nonwoven fabric, and t represents the thickness (c) of the nonwoven fabric.
m), and ρ is the density (g / g) of the long fibers constituting the nonwoven fabric.
cm ³ ), and w is the weight (g / c) of the nonwoven fabric having the area S.
m ² ). The thickness was measured by applying a load of 4.5 g / cm ^{2 to} the nonwoven fabric.

The tensile strength of the elastic long-fiber nonwoven fabric is preferably 35 kg / 5 cm or more in the longitudinal direction.
If the tensile strength is lower than this value, the nonwoven fabric may be broken when used in an application to which a relatively large external force is applied. The method for measuring the tensile strength is the same as the method for measuring the elongation at break, which is a value obtained by measuring the load when the sample piece breaks and converting the average value to a basis weight of 100 g / m ² .

The total hand value of the stretchable nonwoven fabric of the present invention is preferably 2.5 g / g / m ² or less, and most preferably 2.0 g / g / m ² or less. preferable. When the total hand value exceeds 2.5 g / g / m ² , a stretchable long-fiber nonwoven fabric lacking in flexibility is obtained.
In particular, when the stretchable long-fiber nonwoven fabric according to the present invention is used as a medical hygiene material applied to a human body, a flexible material having a total hand value of 2.5 g / g / m ² or less is used. Is preferred. Total hand value is JI
It is a value obtained by dividing the value measured according to the method described in the handle ometer method of SL-1096 by the basis weight.

The nonwoven fabric having good elasticity according to the present invention can be produced by the following method. First, a polymer A and a polymer B are prepared. The polymers A and B
Can employ any combination of various materials as described above. These two types of polymers are respectively fed into a composite melt spinning apparatus, and in a molten state, introduced into a spinneret having a composite spinning hole and discharged. For example, when producing an eccentric core-sheath latently crimpable filament, the molten polymer A is introduced into the core of the composite spinning hole, and the melted weight is introduced into the sheath of the composite spinning hole. Coalescing B is introduced. Then, the eccentric core-sheath composite long fiber is spun from the spinneret. Further, in the case of producing a parallel type latently crimpable continuous fiber, the polymer A melted in the crescent hole on the right side of the composite spinning hole and the polymer B melted in the crescent hole on the left side are introduced. , Just spin it. Thereafter, the spun fibers are cooled using a conventionally known cooling device. Next, it is pulled and thinned to the target fineness using the air soccer method or the Docan method. At this time, the towing speed is 3000
m / min or more, and most preferably 3500 m / min. By applying such high-speed traction, long fibers with high crystallinity and high orientation can be obtained,
The breaking elongation of such a long fiber is described in JP-A-2-33369.
Is much lower than that described in the official gazette, approximately 150%
Below.

The drawn and thinned latently crimpable filaments are spread by a conventionally known spreading method such as a corona discharge method or a triboelectric charging method, and then are moved to a collecting conveyor such as a wire mesh screen conveyor. Deposited on it to form a fibrous web. The fiber web is partially heated. And
At a portion where the heat is partially applied, the polymer B exposed on the surface of the latently crimpable filaments is softened or melted to form a fusion zone where the latently crimpable filaments are fused to each other. I do.
The fusion zones are provided in a scattered manner in the fibrous web, and the fusion zones are arranged at predetermined intervals. Here, the temperature at which the heat is applied to the fibrous web is preferably within a certain range below the melting point of the polymer B. When this temperature exceeds the melting point of the polymer B, the fusion in the fusion area is severe, and when the fiber fleece is hot-drawn, a hole may be opened in the fusion area. It becomes hard. On the other hand, if this temperature is below the melting point of the polymer B and exceeds a certain range and is too low, the fusion between the latently crimpable filaments is insufficient, and when the fiber fleece is hot-drawn, the length of the filaments becomes longer. There is a risk that the fibers may come off. In addition, the breaking strength of the obtained nonwoven fabric becomes insufficient. Therefore, the temperature at which heat is applied to the fiber web is (the melting point of the polymer B−5 ° C.)
To (the melting point of the polymer B−30 ° C.).

As a method for partially applying heat to the fibrous web, an embossing device including an uneven roll and a smooth roll or an embossing device including a pair of uneven rolls is used, and the uneven roll is heated to give the fiber web. What is necessary is just to press the convex part. In addition, these convex portions are arranged on the uneven roll surface in a scattered manner. At this time, it is preferable that the concavo-convex roll is heated to a temperature within a certain range below the melting point of the polymer B as described above. The shape of the tip surface of each convex portion of the concave-convex roll can be any shape such as a round shape, an elliptical shape, a diamond shape, a triangular shape, a T shape, a well shape, and a rectangular shape. Also, the fusion zone may be formed using an ultrasonic welding device. The ultrasonic welding apparatus irradiates a predetermined area of the fibrous web with ultrasonic waves, and generates a polymer B by friction heat between the latently crimpable filaments in the area.
Is softened or melted. When heat is applied to provide a heat-sealed area in the fibrous web, depending on this temperature, crimps may appear in the latently-crimpable filament. In the present invention, the crimp development is completely equalized at the time of the final heat treatment. However, at this time, even if the crimp is developed in the latently crimpable long fiber, there is no problem.

As described above, after obtaining the fiber fleece in which the heat-fused areas are arranged in a scattered manner, the fiber fleece is expanded in the width direction as desired. This widening can be performed using an apparatus such as an expander roll or a greed gear. The widening is preferably performed under heating, and is preferably performed under an atmosphere in which hot air of 40 to 80 ° C. is blown. This is because by slightly plasticizing the latently crimpable long fibers under heating, it becomes easier to widen at a desired widening ratio. The width of fiber fleece in the width direction is 5
It is preferably about 50%. When the expansion ratio is less than 5%, the basis weight of the nonwoven fabric after the subsequent hot stretching treatment is greatly increased, and it becomes difficult to obtain a low-weight nonwoven fabric. However,
When the stretching ratio does not need to be increased, the widening ratio is 5%.
Needless to say, the width may be smaller than that, and furthermore, it is not necessary to widen the width. If the width ratio exceeds 50%, the fiber fleece may be broken. In addition, the expansion rate (%) of the fiber fleece is represented by {[(width after widening)-(width before widening)] / width before widening} × 100.

Next, the expanded fiber fleece is subjected to hot stretching in the longitudinal direction of the fiber fleece while maintaining the state. The stretching is performed by a known method, for example, between a supply roll and a stretching roll rotating at a higher peripheral speed than the supply roll. This stretching is also performed under heating, and it is preferable to perform the stretching under heating at a temperature equal to or lower than the melting point of the polymer B. A preferred embodiment of the hot stretching, which also serves as a heat treatment, is as follows.

(I) A method using a supply roll heated to about 60 to 150 ° C. and a stretching roll heated to a temperature higher than the supply roll by 10 to 30 ° C. or more. In this method, when the fiber fleece is drawn out from the supply roll, hot drawing is performed. Then, heat treatment is performed when the fiber fleece is introduced into a drawing roll. In this case, a heating zone may be provided between the supply roll and the stretching roll. The heating zone is at a temperature approximately between the heating temperature of the supply roll and the heating temperature of the stretching roll,
Preferably it is heated. Also, this heating zone
Instead of being provided between the supply roll and the stretching roll, it may be provided during the process after passing through the stretching roll. The heating zone only needs to heat the fiber fleece, and any means such as dry heat or wet heat is employed. For example, as the dry heat, heating by an oven, heating by infrared rays, heating by contact with a heat plate, and the like are preferable.
As the moist heat, it is preferable to pass the fiber fleece into hot water or moist heat steam.

(Ii) Supply roll at normal temperature, 70-200
A method using a stretching roll heated to at least 0 ° C. or higher, and a heating zone provided between the supply roll and the stretching roll and heated at a temperature lower than the heating temperature of the stretching roll is exemplified. In this method, hot drawing is performed when the fiber fleece passes through the heating zone. Then, heat treatment is performed when the fiber fleece is introduced into a drawing roll. As for the heating zone, various means can be adopted as in the case of (i) described above.

(Iii) 10 to 30 ° C. higher than the heating temperature of the supply roll heated to about 60 to 150 ° C., the stretching roll at normal temperature, and the supply roll installed behind the stretching roll.
A method using a heating zone heated to a higher temperature as described above may be used. In this method, when the fiber fleece is drawn out from the supply roll, hot drawing is performed. Then, the fiber fleece is introduced into a drawing roll at room temperature, and then heat-treated when passing through a heating zone provided behind. The heating zone is described in (i) above.
As in the case of the above, various means can be adopted.

(Iv) A supply roll at normal temperature, a stretching roll at ordinary temperature, a first heating zone X provided between the supply roll and the stretching roll, and a second heating zone provided behind the stretching roll. And a method using the part Y. The heating zone Y is heated at a higher temperature than the heating zone X. Generally, the temperature of the heating zone X is preferably about 60 to 150 ° C., and the temperature of the heating zone Y is preferably higher than the temperature of the heating zone X by 10 to 30 ° C. or more. In this method, hot drawing is performed when the fiber fleece passes through the heating zone X. Then, the fiber fleece is introduced into a drawing roll at room temperature, and then heat-treated when passing through a heating zone Y provided behind. As for the heating zone portions X and Y, various means can be adopted as in the case of (i) described above.

The polymers A and B are plasticized by such thermal drawing, and the drawing by shear deformation of both components is performed on the latently crimpable filaments. In addition, since the latently crimpable long fibers in the fiber fleece are rearranged in the machine direction while maintaining the fusion between the long fibers in the fusion area to some extent, the elasticity in the width direction is developed. is there.

The degree of hot stretching is required to be 10 to 80% of the elongation at break in the longitudinal direction of the fiber fleece, preferably about 40 to 75%. . Here, the stretching ratio means the ratio of the elongation at the time of stretching to the elongation at break in the machine direction of the fiber fleece expressed as a percentage. Therefore, if the elongation at break in the longitudinal direction of the fiber fleece is Q%, (0.1 ×
Q〜0.8 × Q)%, which means that the fiber fleece is stretched in the longitudinal direction. If the draw ratio is less than 10%, the latently crimpable long fibers in the fiber fleece will not be sufficiently rearranged in the machine direction, and the stretchability in the width direction will be insufficient. Furthermore, the number of intersections between latently crimpable filaments is small, and formation may be deteriorated when crimping occurs. Also,
If the stretching ratio exceeds 80%, the stretching is too large, and the potentially crimped long fibers in the fiber fleece may be broken. The elongation at break (%) of the fiber fleece in the machine direction is
According to the method described in JIS-L-1096A, it is measured in the same manner as in the case of measuring the breaking elongation of the nonwoven fabric described above.

The heat-stretched fiber fleece is subjected to a heat treatment at a temperature equal to or lower than the melting point of the polymer B, so that the crimping of the latently crimpable filaments is completed. As mentioned above,
In some cases, the latently crimpable continuous fiber develops crimp in the heat fusion step or the hot stretching step, but finally the crimp development is completed by the final heat treatment. Therefore, it is generally preferable to set the temperature of the heat treatment higher than the temperature given during the heat fusion or the hot stretching. This heat treatment can also be performed with dry heat or wet heat. In addition, this heat treatment may be performed with the fiber fleece relaxed, or may be performed with tension or constant length. In particular, when performed in a relaxed manner, since an external force for preventing the appearance of crimp does not work, good stretchability can be imparted to the obtained nonwoven fabric. Such a heat treatment can be performed by the above-mentioned means (i) to (iv), or separately by introducing a fiber fleece into a heat drum or an oven.

FIG. 1 is a flowchart showing a method for producing a stretchable long-fiber nonwoven fabric according to the present invention.
That is, after obtaining a fiber fleece by a predetermined method (step 1), the fiber fleece is expanded under heating (step 2). Next, the fiber fleece in the widened state is thermally drawn under heating (step 3). After the heat stretching, heat treatment is performed under heating (step 4). Then, the obtained nonwoven fabric may be wound up as desired (step 5). Each of these steps is typically performed continuously online.
However, the step of obtaining the fiber fleece by separating Step 1 and Step 2 and subsequent steps and the step of widening, drawing, and heat treatment after Step 2 may be performed in separate steps. In the method for producing a stretchable long-fiber nonwoven fabric according to the present invention, the porosity of the obtained stretchable long-fiber nonwoven fabric is greater than the porosity of the fiber fleece, as suggested by the description in Examples below. It is common for it to be large. Such a phenomenon,
It is considered that this is mainly because the voids between the long fibers are expanded by the appearance of crimps of the latently crimpable long fibers.

The stretchable long-fiber nonwoven fabric obtained as described above can be used as it is for various conventionally known uses, particularly for use in medical hygiene materials, and as shown in FIG. They can be laminated and used for various purposes. Further, it is used for various applications as a three-layer laminate in which elastic films 2 and 2 are laminated on both sides of elastic long fiber nonwoven fabric 1 or elastic long fibers nonwoven fabrics 1 and 1 are laminated on both surfaces of elastic film 2. You can also. In addition, it goes without saying that the stretchable long-fiber nonwoven fabric according to the present invention is not limited to such a use form, and may be used in any use form.

[0042]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. The methods for measuring the physical properties and the like used in the examples are as follows. Measurement of elongation at break (%), elongation recovery rate (%), porosity (%), widening rate (%), tensile strength (kg / 5 cm width) and total hand value (g / g / m ² ) The method is as described above. (1) Melting point (° C.): using a differential device calorimeter DSC-2 manufactured by PerkinElmer, sample weight 5 mg, heating rate 20
The temperature at which the maximum value of the melting endothermic curve was obtained as measured in ° C./min was defined as the melting point. (2) Basis weight (g / m ² ): From the standard sample, 10
After preparing 10 sample pieces of 10 cm × 10 cm in width and adjusting the equilibrium moisture content, the weight (g) of each sample piece is weighed, and the average value of the obtained values is converted into a unit area to obtain a weight per unit area (g / g). m ² ).

Example 1 As the polymer A, a high-viscosity polyethylene terephthalate having a melting point of 256 ° C. and an intrinsic viscosity of 0.64 was prepared. As the polymer B, a low-viscosity polyethylene terephthalate having a melting point of 256 ° C. and an intrinsic viscosity of 0.48 was prepared. These two types of polymers A and B were introduced into a spinneret equipped with a composite spinning hole using separate extruder type melt extruders.
At this time, the composite spinning hole is a round shape in which the semilunar holes are bonded together, so that the melted high-viscosity polyethylene terephthalate is introduced into one of the semilunar holes, and the other is into the other semilunar hole. Composite melt spinning was performed under the condition of a single hole discharge rate of 1.5 g / min so that the molten low-viscosity polyethylene terephthalate was introduced and the weight ratio of the two was equal. The yarn group spun out of the spinneret was cooled by a known cooling device, and pulled using an air sucker installed below the spinneret so that the drawing speed was 4500 m / min. Thereafter, the yarn group was spread by a fiber opening device provided at the outlet of the air soccer, and was deposited on a moving screen conveyor made of wire mesh to obtain a fiber web having a basis weight of 30 g / m ² . At this time, the fineness of the side-by-side latent crimpable long fibers constituting the fiber web was 3 denier.

Next, the fibrous web was introduced between an uneven roll heated to 235 ° C. and a smooth roll heated to 235 ° C. As a result, the area of the fiber web in contact with the convex portion of the concave-convex roll is partially heated, and the polymer B of the latently-crimpable long fiber is softened or melted, and the space between the latently-crimpable long fibers is reduced. Fused. As a result, a fiber fleece in which the fusion zones were arranged in a scattered manner was obtained. The area of each fusion zone was 0.6 mm ² , the density of the fusion zone in the fiber fleece was 20 pieces / cm ² , and the total area of the fusion zone was 15% of the fiber fleece surface area. Was. Also,
The longitudinal elongation at break of this fiber fleece was 65%. Further, the density of the latently crimpable long fibers constituting the fiber fleece was 1.300 g / cm ³ , and the porosity of the fiber fleece was 85.3%.

This fiber fleece was introduced into a pressurized steam treatment machine equipped with a clip tenter, and was expanded in a width direction by 15% in an atmosphere of 70 ° C. And in this widened state,
The fiber fleece was hot drawn in the machine direction. As the stretching conditions, a one-stage stretching method was applied, and the film was introduced into a supply roll at a temperature of 100 ° C., and then introduced into a stretch roll at a temperature of 170 ° C., and the stretching ratio was 47.7%. Then, the fiber fleece after the heat drawing was introduced into a heat oven at 245 ° C., and heat-treated to obtain a stretchable long-fiber nonwoven fabric. Table 1 shows the physical properties of the stretchable long-fiber nonwoven fabric.

[0046]

[Table 1] In Table 1, the basis weight is the weight (g) per 1 m ² of the nonwoven fabric, EC is the breaking elongation (%) in the width direction of the nonwoven fabric,
EM is the elongation at break (%) of the nonwoven fabric in the longitudinal direction,
(50) is the elongation recovery rate (%) when the nonwoven fabric is stretched 50% in the width direction, and EEC (100) is the elongation recovery rate (%) when the nonwoven fabric is stretched 100% in the width direction. The hand value indicates the flexibility of the nonwoven fabric.

Example 2 A stretchable long-fiber nonwoven fabric was obtained under the same conditions as in Example 1 except that the stretching ratio was 56.9%. The physical properties are shown in Table 1.

Example 3 A stretchable long-fiber nonwoven fabric was obtained under the same conditions as in Example 1 except that the stretching ratio was 72.3%, and the physical properties are shown in Table 1.

Example 4 As a polymer A, polyethylene terephthalate having a melting point of 256 ° C. and an intrinsic viscosity of 0.64 was prepared. Polymer B
A copolymer polyester obtained by copolymerizing 8 mol% of isophthalic acid having a melting point of 232 ° C. and an intrinsic viscosity of 0.66 was prepared. Using these two polymers A and B, the basis weight was 30 g / min in the same manner as in Example 1 except that the single hole discharge rate was 1.43 g / min and the traction speed by air soccer was 4300 m / min. An m ² fiber web was obtained. The fineness of the side-by-side latently crimpable long fibers constituting the fiber web was 3 denier.

A fiber fleece was prepared by providing a fusion zone in the same manner as in Example 1 except that the heating temperature of the uneven roll and the smooth roll was set to 210 ° C. The breaking elongation in the machine direction of this fiber fleece was 60%.
Further, the density of the latently crimpable long fibers constituting the fiber fleece was 1.295 g / cm ³ , and the porosity of the fiber fleece was 85.1%. Then, the fiber fleece was widened under the same conditions as in Example 1, and in this widened state, the fiber fleece was hot-drawn in the longitudinal direction. As the stretching conditions, a one-stage stretching method was applied, and the film was introduced into a supply roll at a temperature of 90 ° C., and then introduced into a stretch roll at a temperature of 145 ° C., and the stretching ratio was 48.3%. Then, the fiber fleece after the heat drawing was introduced into an oven at 220 ° C., and heat-treated to obtain a stretchable long-fiber nonwoven fabric. Table 1 shows the physical properties of the stretchable long-fiber nonwoven fabric.

Example 5 As a polymer A, polyethylene terephthalate having a melting point of 256 ° C. and an intrinsic viscosity of 0.64 was prepared. Polymer B
A copolymerized polyester prepared by copolymerizing 16% by mole of isophthalic acid having a melting point of 201 ° C. and an intrinsic viscosity of 0.65 was prepared. Using these two polymers A and B, the basis weight was 30 g / min in the same manner as in Example 1 except that the single hole discharge rate was 1.37 g / min and the traction speed by air soccer was 4100 m / min. An m ² fiber web was obtained. The fineness of the side-by-side latently crimpable long fibers constituting the fiber web was 3 denier.

This fiber web was provided with a fusion zone in the same manner as in Example 1 except that the heating temperature of the concavo-convex roll and the smooth roll was set at 180 ° C., to produce a fiber fleece. The elongation at break in the machine direction of this fiber fleece was 57%.
In addition, the density of the latently crimpable continuous fibers constituting the fiber fleece was 1.290 g / cm ³ , and the porosity of the fiber fleece was 84.7%. Then, the fiber fleece was widened under the same conditions as in Example 1, and in this widened state, the fiber fleece was hot-drawn in the longitudinal direction. As the stretching conditions, a one-stage stretching method was applied, and the film was introduced into a supply roll at a temperature of 80 ° C., and then introduced into a stretch roll at a temperature of 115 ° C., and the stretching ratio was 47.4%. Then, the fiber fleece after the heat drawing was introduced into a heat oven at 190 ° C. and heat-treated to obtain a stretchable long-fiber nonwoven fabric. Table 1 shows the physical properties of the stretchable long-fiber nonwoven fabric.

Example 6 As a polymer A, a high melting point copolyester prepared by copolymerizing 8% by mole of isophthalic acid having a melting point of 232 ° C. and an intrinsic viscosity of 0.66 was prepared. The melting point of the polymer B is 201 ° C.
A low melting point copolyester prepared by copolymerizing 16 mol% of isophthalic acid having an intrinsic viscosity of 0.65 was prepared. Using these two types of polymers A and B, the basis weight was 30 g / min in the same manner as in Example 1 except that the single hole discharge amount was 1.33 g / min and the traction speed by air soccer was 4000 m / min. m ²
Was obtained. The fineness of the side-by-side latently crimpable long fibers constituting the fiber web was 3 denier.

The fiber web was provided with a fusion zone in the same manner as in Example 5 to produce a fiber fleece. The longitudinal elongation at break of this fiber fleece was 53%. Also,
The density of the latently crimpable long fibers constituting the fiber fleece was 1.285 g / cm ³ , and the porosity of the fiber fleece was 84.4%. Then, the fiber fleece is widened under the same conditions as in Example 5, and in this widened state,
Except for changing the stretching ratio to 47.1%, hot stretching and heat treatment were performed under the same conditions as in Example 5 to obtain a stretchable long-fiber nonwoven fabric. Table 2 shows the physical properties of the stretchable long-fiber nonwoven fabric.

[0055]

[Table 2] In Table 2, each item is the same as in Table 1.

Comparative Example 1 A nonwoven fabric was obtained under the same conditions as in Example 1 except that the basis weight of the fibrous web was 40 g / m ² and no widening, hot stretching and heat treatment were applied. The physical properties of this nonwoven fabric were as shown in Table 2.

Comparative Example 2 Melt flow rate value at a melting point of 160 ° C. (ASTM D1
238 (L), measured in accordance with the method described in 238 (L)) 30 g / 1
Only 0 minute polypropylene was prepared. Then, this polypropylene is supplied to a spinneret having a spinning hole having a single-phase round cross-section using an extruder-type melt extruder, and the single-hole discharge rate is 1.27 g / min. To perform melt spinning. The drawing speed of the spun yarn group is 380.
A fiber web having a basis weight of 30 g / m ² was obtained in the same manner as in Example 1 except that the fiber web was set at 0 m / min. At this time, the fineness of the single-phase round cross-section long fiber constituting the fiber web was 3 denier.

A fiber fleece was prepared by providing a fusion zone in the same manner as in Example 1 except that the heating temperature was 145 ° C. The longitudinal elongation at break of this fiber fleece was 80%. In addition, the density of the single-phase round cross-section polypropylene long fiber constituting the fiber fleece is
0.86 g / cm ³ , and the porosity of the fiber fleece is 7
It was 3.9%. Then, the fiber fleece was set to a temperature of a supply roll of 90 ° C.
° C, a stretching ratio of 57.5%, and a heat treatment temperature using a heat drum of 150 ° C, and in the same manner as in Example 1, a widening process, a hot stretching process and a heat treatment are performed to obtain a stretchable polypropylene-based resin. A non-woven fabric was obtained. Table 2 shows the physical properties of the stretchable polypropylene nonwoven fabric.

As is clear from the results of Tables 1 and 2,
The stretchable long-fiber nonwoven fabrics obtained by the methods according to Examples 1 to 6 were all excellent in stretchability in the width direction. And, as the stretching ratio is increased, the elongation in the width direction is increased, and the elongation recovery is also increased. Also,
Since the stretchable long-fiber nonwoven fabric obtained by the method according to Examples 1 to 6 has the crimped long fiber as a constituent fiber due to the crimping of the latently-crimpable long fiber, it has a certain degree of elongation even in the longitudinal direction. There was elongation recovery, and the overall elasticity was also excellent. In the method according to Comparative Example 1, since the heat stretching and the heat treatment were not performed, the elongation and the elongation recovery were insufficient as a whole, and were far from an elastic long-fiber nonwoven fabric. In addition, in the method according to Comparative Example 2, since the non-composite type single-phase long fiber was used as the long fiber, as can be seen from the fact that the basis weight was lower than in Examples 1 to 6, during the hot stretching, Single-phase filaments tend to come off,
In addition, no crimping occurs in the long fibers during the heat treatment. Therefore,
Both stretchability and stretch recovery were insufficient, and were far from stretchable long-fiber nonwoven fabrics. Furthermore, as is clear from the results of Tables 1 and 2, the porosity of the stretchable long-fiber nonwoven fabric obtained by the method according to Examples 1 to 6 is larger than the porosity of the fiber fleece before widening and stretching. You can see that it has become.

[0060]

The stretchable long-fiber nonwoven fabric according to the present invention comprises, as a constituent fiber, a crimped long fiber in which a latently crimpable long fiber has been developed, and a polymer constituting the latently crimpable long fiber. Among them, the fused areas where the long fibers are fused by softening or melting of the polymer B having a large heat shrinkage are arranged in a scattered manner, and simultaneously satisfy the following four conditions. It is. That is, (i) the breaking elongation in the width direction of the nonwoven fabric is 1
(Ii) the ratio of the elongation at break in the width direction to the elongation at break in the longitudinal direction of the nonwoven fabric is 5 or more;
i) The elongation recovery rate when elongating the nonwoven fabric by 50% in the width direction is 60% or more;
It satisfies that the elongation recovery rate at the time of% elongation is 50% or more. Therefore, it has the effect of exhibiting extremely large elasticity in the width direction and also exhibiting the elasticity of the crimped long fiber itself in the vertical direction. Further, the porosity of the stretchable long-fiber nonwoven fabric according to the present invention is 85%
% Or more, there is an effect of being excellent in water permeability and liquid permeability.

Further, the method for producing a stretchable nonwoven fibrous nonwoven fabric according to the present invention is characterized in that the latent crimpable long fibers are constituted by interposing the latent crimped long fibers by softening or melting of the polymer B. A fiber fleece in which the fused areas are arranged in a scattered manner is used and subjected to thermal drawing. Therefore, as in the case of a fiber fleece composed of long fibers (single-phase long fibers) composed of a single component and having a similar fusion zone, the fusion zone collapses during hot stretching (single-phase length). When the fusion between the fibers is severe, the long fibers are rarely removed (when the fusion between the single-phase long fibers is insufficient). That is, in the case of fusion with the polymer B, the polymer A often exists while maintaining a fiber form to some extent even in the fusion zone, so that the fusion zone can be prevented from collapsing, Since the coalesced A retains the fiber form, the polymer B can be sufficiently softened or melted, and insufficient fusion can be prevented.

In the method for producing a stretchable long-fiber nonwoven fabric according to the present invention, the fiber fleece is expanded in the width direction as desired before the hot stretching. Even so, there is an effect that the width of the obtained elastic long-fiber nonwoven fabric can be reduced and the basis weight can be reduced. In addition, since the obtained stretchable long-fiber nonwoven fabric can be inevitably stretched up to the width at the time of widening, there is also an effect that high stretchability and stretch recovery can be ensured.

Further, in the method for producing a stretchable long-fiber nonwoven fabric according to the present invention, heat treatment is performed after hot stretching.
The crimping occurs in the latently crimpable long fibers arranged in the longitudinal direction by stretching. That is, since the latently-crimpable filaments that are randomly accumulated are arranged in the longitudinal direction, the number of intersections between the latently-crimpable filaments decreases, and crimping occurs in this state. Therefore, the number of intersections between latently crimped filaments is relatively large, and compared with the case where crimps are expressed in a fiber fleece in which filaments are accumulated at random, the filaments are located at the intersections between filaments. The convergence is also reduced, and the effect of preventing the formation of the obtained nonwoven fabric from being deteriorated is also exerted. Then, the latently crimpable long fibers rearranged in the longitudinal direction of the fiber fleece at the time of stretching, since crimping occurs in a rearranged form, the obtained stretchable long-fiber nonwoven fabric is formed in the longitudinal direction of the long fibers. Not only elongation and elongation recovery in the width direction due to rearrangement but also elongation and elongation recovery due to the crimped fiber itself are given in the longitudinal direction. Accordingly, the method according to the present invention has an effect that a nonwoven fabric having good formation and relatively elasticity as a whole can be obtained.

Further, in the method for producing a stretchable long-fiber nonwoven fabric according to the present invention, it is possible to make the porosity of the stretchable long-fiber nonwoven fabric larger than that of the fiber fleece. It is considered that the reason for this is that, as described above, latently crimpable long fibers are used as the constituent fibers, and the crimps are developed to expand the gaps between the long fibers. Therefore, it is possible to obtain a stretchable long-fiber nonwoven fabric having a relatively large porosity, and to efficiently obtain a stretchable long-fiber nonwoven fabric having excellent water permeability and liquid permeability, as well as excellent elasticity in the thickness direction. To play. Therefore, the stretchable long-fiber nonwoven fabric according to the present invention or the stretchable long-fiber nonwoven fabric obtained by the method according to the present invention can be suitably used particularly for medical hygiene materials.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an example of manufacturing a stretchable long-fiber nonwoven fabric according to the present invention.

FIG. 2 is a cross-sectional view of a laminate according to one use example of a stretchable long-fiber nonwoven fabric according to the present invention.

[Explanation of symbols]

 1 Elastic long-fiber nonwoven fabric 2 Elastic film

Claims (7)

[Claims] 1. A fiber-forming polymer A and a fiber-forming polymer B having a higher heat shrinkage than the polymer A are composited in such a form that the polymer B is exposed at least on a part of the surface. The crimped filaments obtained by crimping the latently crimped filaments are formed, and the polymer B is formed between the crimped filaments.
Characterized in that the fused areas fused by softening or melting are provided in a scattered manner and simultaneously satisfy the following formulas (1) to (4). EC ≧ 150% (1) EC / EM ≧ 5 (2) EEC (50) ≧ 60% (3) EEC (100) ≧ 50% (4) (However, , EC is the elongation at break in the width direction of the nonwoven fabric, EM
Is the elongation at break in the longitudinal direction of the nonwoven fabric, EEC (50) is the elongation recovery rate when the nonwoven fabric is stretched by 50% in the width direction, and EEC (100) is the stretch recovery rate when the nonwoven fabric is stretched by 100% in the width direction. Elongation recovery rate. ) 2. The stretchable long fiber according to claim 1, wherein the fiber-forming polymer A and the fiber-forming polymer B are used as latently crimpable long fibers which are combined in an eccentric core-sheath type or a side-by-side type. Non-woven fabric. 3. The fineness is 15 denier or less, and the composite weight ratio of the fiber-forming polymer A and the fiber-forming polymer B is:
The stretchable long-fiber nonwoven fabric according to claim 1 or 2, wherein latent crimpable long fibers in which the polymer A: the polymer B = 1: 0.1 to 5 are used. 4. The stretchable long-fiber nonwoven fabric according to claim 1, which has a porosity of 85% or more. 5. A fiber-forming polymer A and a fiber-forming polymer B having a higher heat shrinkage than the polymer A are composited in such a form that the polymer B is exposed at least on a part of the surface. The latently crimpable filaments are deposited on a collecting conveyor to form a fibrous web, and heat is partially applied to the fibrous web so that the latent crimpable filaments are separated from each other by the polymer B. After obtaining a fiber fleece in which the fusion zone fused by softening or melting of the fiber fleece is provided in the fiber web in a scattered manner, the fiber fleece is expanded so as to have a width expansion ratio of 0 to 50% in the width direction. In the widened state, the fiber fleece is hot-stretched in the machine direction at a draw ratio of 10 to 80%, and then heat-treated at a temperature equal to or lower than the melting point of the polymer B, so as to be wound on the latently crimpable filament. A method for producing a stretchable long-fiber nonwoven fabric, characterized by causing shrinkage. 6. The fiber fleece has a width expansion ratio of 5 to 5 in the width direction.
The method for producing a stretchable long-fiber nonwoven fabric according to claim 5, which is 0%. 7. The method for producing a stretchable long-fiber nonwoven fabric according to claim 5, wherein the porosity of the stretchable long-fiber nonwoven fabric is larger than the porosity of the fiber fleece.