JPH1096153A - Stretchable nonwoven fabric and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stretchable nonwoven fabric excellent in mechanical characteristics and softness, having stretchability and water soluble property and free from lowering of nonwoven fabric strength even in wet state and provide a method for producing the nonwoven fabric. SOLUTION: This nonwoven fabric is obtained by blending a synthetic short fiber comprising two or more kinds of thermoplastic polymer components different in heat shrinkage with a fiber having water absorption in (40/60) to (70/30) weight ratio of synthetic short fiber/fiber having water absorption. The synthetic short fiber is a latent crimpable fiber having either one shape among a shape in which two or more kinds of thermoplastic polymer components are parallel arranged along the length direction of yarn and shapes in which two or more kinds of thermoplastic polymer components are arranged in eccentric core-sheath structure on fiber cross section. Latent crimp of a synthetic short fiber is actualized and three-dimensional entanglement is formed among constituent fibers of the nonwoven fabric to retain the form of the nonwoven fabric.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stretchable nonwoven fabric which has water absorption and does not reduce the strength of the nonwoven fabric even when wet, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, stretchable fabrics made of synthetic fibers have been proposed. For example, JP-A-63-28960
In the gazette, a method for obtaining a stretch nonwoven fabric by subjecting a nonwoven web composed of short fibers having latent crimps to three-dimensional entanglement by a high-pressure liquid flow, then performing a relaxation heat shrinkage treatment, and manifesting the latent crimps Has been proposed. However, this stretchable nonwoven fabric is made of only synthetic fibers and does not contain fibers having water absorbency, and although it has excellent stretchability, it has poor water absorbency, and when used in a wet state, there is a problem in that short fibers may fall off. is there.

[0003] Also, JP-A-2-91217 discloses that
After making a nonwoven fabric by performing needle punching on a nonwoven web made of synthetic fiber, by applying a relaxation heat shrinkage treatment to make latent crimps visible, the crimps are developed to make the nonwoven fabric elastic. A method of applying is proposed. However, in this method, the nonwoven fabric is formed by needle punching, and a high nonwoven fabric weight is required to maintain the mechanical strength of the nonwoven fabric. It has the disadvantage of low mechanical strength.

On the other hand, as a stretchable nonwoven fabric made of synthetic long fibers, Japanese Patent Application Laid-Open No. 63-282350 and
No. 01567 proposes a method based on a spun bond method. Although these nonwoven fabrics are made of long fibers composed of a thermoplastic polymer, they are excellent in mechanical strength and stretchability, but are subjected to heat bonding treatment to form long-fibers to form a nonwoven fabric. And poor water absorption.

Further, Japanese Patent Application Laid-Open No. Sho 59-223347 proposes a stretchable nonwoven fabric containing a thermoplastic polyurethane elastic material as a component. This nonwoven fabric is also excellent in stretchability and mechanical strength, but has the disadvantage of poor water absorption due to the dense structure of the nonwoven fabric surface.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems, and is an elastic nonwoven fabric which has excellent mechanical properties and flexibility, has elasticity and water absorption, and does not decrease the strength of the nonwoven fabric even in a wet state. And a method for producing the same.

[0007]

Means for Solving the Problems The present inventors have accomplished the present invention as a result of intensive studies to solve the above-mentioned problems. That is, the present invention has the following gist.

(1) Synthetic short fibers composed of two or more thermoplastic polymer components having different heat shrinkages from each other and water-absorbing fibers are defined as: synthetic short fibers / water-absorbing fibers = 40
/ 60 to 70/30 (% by weight), wherein the synthetic short fibers are formed by juxtaposing the two or more thermoplastic polymer components along the length direction of the yarn. And said 2
A latent crimpable fiber having at least one kind of thermoplastic polymer component having any one of a shape arranged in an eccentric core-sheath structure in a fiber cross section, and a latent crimp of the synthetic short fiber. Characterized by the fact that the constituent fibers of the nonwoven fabric are retained in shape by having three-dimensional confounding with each other, and that the nonwoven fabric has a stretch elastic recovery rate of 80% or more when stretched by 30%. Nonwoven fabric.

(2) Two or more kinds of thermoplastic polymer components having mutually different heat shrinkages are used, and the two or more kinds of thermoplastic polymer components are juxtaposed along the length direction of the yarn. A synthetic short fiber having a latent crimping property is obtained so as to have any one of a shape and a shape in which the two or more thermoplastic polymer components are arranged in an eccentric core-sheath structure in a fiber cross section. The synthetic short fiber and the water-absorbing fiber are combined with a synthetic short fiber /
Water-absorbing fiber = 40/60 to 70/30 (% by weight) is mixed and defibrated to form a nonwoven web, which is then subjected to high-pressure liquid flow treatment. By forming a three-dimensional entanglement between the constituent fibers to maintain the form as a nonwoven fabric, and then subjected to a drying treatment,
Then, a latent heat crimping treatment is applied to make the latent crimps visible, thereby causing area shrinkage of the nonwoven fabric to impart elasticity.

As described above, according to the present invention, the synthetic short fibers constituting the nonwoven fabric are formed of two or more kinds of thermoplastic polymers having different heat shrinkages, and the two or more kinds of thermoplastic polymer components are formed of yarn. Any of the shapes arranged side by side along the length direction and the shape arranged in the eccentric core-sheath structure in the fiber cross section, and the synthetic short fibers having this latent crimping property are It is contained in an amount of 40 to 70% by weight with respect to the weight of the nonwoven fabric, and its latent crimp is evident by the relaxation heat shrinkage treatment, so that the nonwoven fabric exhibits an area shrinkage to obtain a nonwoven fabric having good elasticity. be able to.

According to the present invention, together with the synthetic staple fiber, the water-absorbing fiber is contained in an amount of 60 to 30% based on the weight of the nonwoven fabric.
Since it is contained by weight, a stretchable nonwoven fabric excellent in water absorption can be obtained, and a decrease in the strength of the nonwoven fabric in a wet state can be avoided.

Furthermore, the nonwoven fabric according to the present invention is maintained in its shape by three-dimensional entanglement between constituent fibers.
A nonwoven fabric having sufficient mechanical properties enough to be put to practical use and having high flexibility is obtained.

According to the invention, the water absorption and the bulk density are preferably 35 m
m / 10 minutes or more, and the bulk density of the nonwoven fabric is 0.04 to
The range is 0.1 g / cc.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The nonwoven fabric of the present invention comprises 40 to 70% by weight of a synthetic short fiber having a latent crimping ability and in which the latent crimp has become apparent, based on the weight of the nonwoven fabric.
If the amount of the synthetic short fiber is less than 40% by weight based on the weight of the nonwoven fabric, the obtained nonwoven fabric will have poor elasticity. Conversely, if the amount of the synthetic short fibers exceeds 70% by weight with respect to the weight of the nonwoven fabric, the stretchability of the nonwoven fabric is obtained, but the water absorption is poor and the strength of the nonwoven fabric in a wet state is reduced.

The synthetic staple fiber according to the present invention has a shape in which thermoplastic polymer components having different heat shrinkages are arranged in parallel along the length direction of the yarn, or the thermoplastic polymer component is deviated in the fiber cross section. The latent crimpability is imparted by being formed in a core-sheath structure. That is, such a synthetic short fiber has a latent crimping ability due to its special fiber shape and a difference in heat shrinkage of its constituent components, and the crimp is developed by the relaxation heat shrinkage treatment. Then, since the manifestation of the latent crimp appears as area shrinkage in the nonwoven fabric, the stretchability of the nonwoven fabric can be improved due to the shrinkage of the area exhibited in the nonwoven fabric.

In the present invention, as the synthetic short fiber having latent crimpability, for example, as shown in FIG. 1, two kinds of thermoplastic polymer components A and B are arranged in parallel along the length direction of the yarn. Each of them has a parallel type shape exposed on the fiber surface. Further, as shown in FIG. 2, there is also a shape in which two kinds of thermoplastic polymer components A and B are arranged in an eccentric core-sheath structure in a fiber cross section. In particular, in the case of a composite cross section having an eccentric core-sheath structure, it is preferable that the high viscosity component A be a core component and the low viscosity component B be a sheath component among the two types of thermoplastic polymer components A and B. . The fiber form may be either a solid fiber or a hollow fiber, and the cross-sectional shape of the fiber may be any of a round cross section, a three-lobe cross section, and other cross sections. As shown in these figures, two kinds of thermoplastic polymer components A and B having different heat shrinkages are arranged in such a form to form a synthetic short fiber. And the potential crimping power is
By applying the relaxation heat shrinkage treatment, it becomes possible to manifest
Therefore, elasticity can be imparted to the nonwoven fabric.

As the combination of thermoplastic polymer components having different heat shrinkages, different or similar thermoplastic polymers may be selected according to the purpose. It is preferable that all of the thermoplastic polymers have a fiber-forming property and can be melt-spun using an ordinary melt-spinning apparatus.

In the case where the fiber shape of the synthetic short fibers is the above-mentioned parallel type shape, the combination of thermoplastic polymers having different heat shrinkage needs to be compatible with each other. In the case of the incompatible combination, peeling occurs during the spinning process at the juxtaposed interfaces, which significantly impairs operability. For this reason, the parallel type polymer component is preferably a combination of the same type of polymers having different viscosities and melting points.

As the combination of the same kind of polymers having different viscosities, it is preferable that the relative viscosity ratio (high viscosity / low viscosity) of the polyester polymer is 1.1 to 1.2.
For a polyolefin-based polymer, especially a polypropylene polymer, the melt flow rate ratio (high melt flow rate / low melt flow rate) measured by the method described in ASTM-D-1238 (L) is 1.2 to 1.6. It is preferred that If the viscosity ratio is too small, the intended latent crimpability cannot be obtained, and if the viscosity ratio is too large, the yarn bending in the spinning hole becomes large, resulting in impaired operability.

As a combination of the same kind of polymers having different melting points, a polyester polymer may be a combination of a homopolymer and a copolymer thereof. For example, a combination of polyethylene terephthalate and ethylene terephthalate / metal sulfonate copolymer or a combination of polyethylene terephthalate and ethylene terephthalate / isophthalic acid copolymer is suitable. Among the polyolefin polymers, a combination of high-density polyethylene and linear low-density polyethylene, a combination of polypropylene and a propylene / ethylene copolymer, and the like are preferable.

When the fiber shape of the synthetic short fibers is the above-mentioned eccentric core-sheath type, the two or more polymers may be compatible or incompatible with each other, and may be selected according to the purpose. Good. When two or more polymers are compatible with each other, the same combination as in the case of the above-mentioned parallel type shape is suitable.
On the other hand, when two or more polymers are incompatible with each other, examples thereof include polyester-based and polyamide-based, polyester-based and polyolefin-based, and polyamide-based and polyolefin-based. Examples of the polyester-based polymer include polyethylene terephthalate, polybutylene terephthalate, and a copolymerized polyester containing these as a main component. Alternatively, a copolymerized polyester elastomer containing a polyester containing polybutylene terephthalate as a main component and a polyether containing polytetramethylene glycol as a main component can be used. Examples of the polyamide-based polymer include nylon 6, nylon 46, nylon 66, nylon 610, and copolymerized nylon containing these as a main component. Examples of the polyolefin-based polymer include polypropylene, high-density polyethylene, linear low-density polyethylene, and ethylene / propylene copolymer. Other combinations include a combination of an ethylene / vinyl acetate copolymer with a polyester, polyamide, or polyolefin.

In addition, the thermoplastic polymer applied to the present invention contains an additive mainly composed of titanium oxide and / or calcium carbonate and / or talc (magnesium silicate hydro-oxide) in an amount of 0.05 to 5%.
It is preferable to add in the range of 0% by weight. This allows
It is possible to suppress the transparency of the polymer to obtain a fiber having a whiteness, to promote the cooling of the melt-spun polymer stream during the melt-spinning, and to improve the spinning property. In addition, other than such additives, various additives such as a pigment, a flame retardant, a deodorant, a light stabilizer, a heat stabilizer, and an antioxidant may be added to the effect of the present invention as necessary. You may add in the range which does not impair.

In the present invention, the synthetic short fiber having latent crimpability preferably has a single yarn fineness of 1.0 to 8.0 denier. When the single-fiber fineness is less than 1.0 denier, the mechanical properties of the obtained nonwoven fabric tend to be reduced, the spinning properties in the melt spinning step tend to be reduced, and the productivity tends to be reduced. Conversely, if the single-fiber fineness exceeds 8.0 denier, the texture of the obtained nonwoven web becomes hard, and it is difficult to obtain a stretchable nonwoven fabric with high flexibility. Therefore, in the present invention, the single-fiber fineness is more preferably 1.3 to 5.0 denier.

Further, the nonwoven fabric of the present invention contains 60 to 30% by weight of water-absorbing fibers based on the weight of the nonwoven fabric. When the water-absorbing fiber exceeds 60% by weight with respect to the weight of the nonwoven fabric, the nonwoven fabric tends to have poor elasticity although good water absorption and strong nonwoven fabric in a wet state can be obtained. On the other hand, if the water-absorbing fiber is less than 30% by weight based on the weight of the nonwoven fabric, not only the strength of the nonwoven fabric in a wet state is reduced but also it is difficult to obtain good water absorption.

The water-absorbing fiber used in the present invention is preferably a fiber which swells in a wet state. By using a fiber that swells by absorbing moisture, a nonwoven fabric having no difference between the nonwoven fabric strength in a dry state and the nonwoven fabric strength in a wet state can be obtained.

The water-absorbing fiber applied to the present invention is not particularly limited as long as it has the above-mentioned performance, that is, a fiber having a good swelling property when wet. Natural fibers such as ramie, wool, and silk cut into short fibers, or regenerated fibers such as viscose rayon, copper ammonia rayon, and Lyocell (registered trademark) fiber which is a solvent-spun rayon are suitable. In particular, lyocell fiber is suitable in terms of the mechanical strength of the nonwoven fabric and the strength in a wet state.

In the present invention, when the above-mentioned cotton fibers are used, bleached cotton fibers or cotton wool fibers can also be used. Here, the anti-hair fiber is obtained from a woven or knitted fabric, thread, or fabric made of cotton, and as a material of the anti-hair obtained from cotton, in addition to a woven or knitted fabric or fabric made of bleached cotton, It may be dyed or printed. Examples of the anti-hair machine that can effectively obtain the anti-hair fiber include a rug machine, a knot breaker, a garnet machine, and a turning machine. The type and combination of anti-hair machines used depends on the shape of the fabric to be anti-haired, the thickness and twist strength of the constituent yarns, etc. It is effective to use a combination of the above-mentioned anti-hair machines. At this time, the defibration rate by the anti-hair machine represented by the following formula is preferably in the range of 50 to 95%.

Fibrillation rate (%) = (weight of unwooled fiber−weight of unfibrillated material) / weight of bristled hair × 100 If the fibrillation rate is less than 50%, unfibrillated fibers are present in the card web, Not only does the nonwoven fabric surface become rough, but the high-pressure liquid flow during the entanglement treatment does not penetrate the web sufficiently, and the constituent fibers of the nonwoven web become insufficiently entangled with each other, which tends to cause a reduction in the strength of the nonwoven fabric. Conversely, the defibration rate is 9
If it exceeds 5%, it is difficult to obtain a sufficient surface friction strength of the nonwoven fabric.

Also, as the fiber having water absorbency, anti-hair fiber obtained from cotton subjected to a fluorescent treatment can be used. The anti-hair fiber obtained from the fluorescence-treated cotton is a cotton fiber subjected to a bleaching process and subjected to a fluorescence treatment. The cotton fiber subjected to the fluorescent treatment is a cotton fiber having a higher whiteness than that of the cotton fiber subjected to a normal bleaching process. The nonwoven fabric of the present invention has excellent whiteness. In particular, when a propylene-based polymer is used as the synthetic short fiber, the resulting nonwoven fabric becomes a nonwoven fabric having good gloss, in combination with the whiteness of the synthetic short fiber.

Further, in the present invention, the use of synthetic short fibers having latent crimping properties as well as anti-hair fibers obtained from cotton subjected to a fluorescent treatment can improve the stretchability. In other words, the anti-hair fiber obtained from the cotton subjected to the fluorescence treatment is used when the solvent and the fluorescent agent used at the time of the fluorescence treatment act to fill the gaps on the fiber surface. The frictional resistance of the anti-hair fibers is weakened, and the shrinkage of the nonwoven fabric can be promoted, and as a result, a nonwoven fabric having good elasticity can be obtained.

In the present invention, a polyester or polyamide is used in combination with the above-mentioned synthetic short fibers and water-absorbing fibers as long as they do not cause a decrease in stretchability, water absorption or strength of the nonwoven fabric in a wet state. A short fiber of a polyolefin type or a polyolefin type may be mixed and used.

As described above, in the present invention, since the nonwoven fabric contains fibers having water absorbency as constituent fibers, when used in daily necessities, clothing, medical use, sanitary materials, etc. The function of the nonwoven fabric can be selected by appropriately selecting the fiber amount of the water-absorbing fiber, or by mixing a plurality of these fibers to form a nonwoven fabric.

The non-woven fabric of the present invention is a non-woven fabric having three-dimensional entanglement between its constituent fibers. The nonwoven fabric having three-dimensional entanglement is one in which fibers constituting the nonwoven web are three-dimensionally entangled and integrated as a whole. The three-dimensional entanglement is formed by a known so-called high-pressure liquid flow treatment, whereby the form of the nonwoven fabric is maintained and a highly flexible nonwoven fabric can be obtained.

The nonwoven fabric of the present invention is provided with elasticity by causing latent crimps to become apparent by the relaxation heat shrinkage treatment described below to cause area shrinkage of the nonwoven fabric. Here, the resulting area shrinkage of the nonwoven fabric is preferably in the range of more than 20% and less than 60% in each of the machine direction and the direction orthogonal to the machine direction. At a shrinkage of 20% or less, the elasticity is suppressed due to three-dimensional entanglement between the constituent fibers, and the substantial elasticity is likely to be impaired. On the other hand, 60%
In order to express the above shrinkage, it is necessary to perform the relaxation heat shrinkage treatment at a temperature very close to the melting point of the component having the lowest melting point among the components constituting the nonwoven web. The nonwoven web not only loses flexibility but also tends to become a non-stretchable nonwoven fabric in which the low melting point component is partially fused.

The stretchable nonwoven fabric of the present invention has a stretch elastic recovery at 80% or more in the machine direction of the nonwoven fabric and in the direction perpendicular thereto when stretched by 30%. 30
When the stretch elastic recovery rate at the time of% elongation is less than 80%, not the stretchable nonwoven fabric intended for the present invention, but, for example, when processed into a patch material and used for a joint,
Sufficient elasticity cannot be obtained and discomfort is likely to occur. In addition, the extension elastic recovery rate is, as described later, JIS-L-1096.
It is measured according to the method described in -6.13.1A.

The stretchable nonwoven fabric of the present invention is characterized in that it has excellent water absorption and that the strength of the nonwoven fabric does not decrease in the wet state compared to the strength in the dry state. That is, the stretchable nonwoven fabric of the present invention has a water absorption of at least 35 mm / 10 minutes as measured by the Vilek method, and a nonwoven fabric strength in a wet state in which 50 to 300% by weight of water is added to the weight of the nonwoven fabric. The strength is preferably in the range of 85 to 110% of the nonwoven fabric strength in the state. Non-woven fabrics having a water absorption of less than 35 mm / 10 minutes have poor water absorption of the non-woven fabric when used in contact with the human body, and particularly when used in the summer season, have poor water absorption and do not absorb sweat sufficiently. Cheap. Also,
A nonwoven fabric in which the strength of the nonwoven fabric in a wet state to which 50 to 300% by weight of water is added to the weight of the nonwoven fabric becomes less than 85% of the strength of the nonwoven fabric in a dry state, the entanglement is released by swelling of the fibers in the wet state. This means that the fibers fall off the nonwoven fabric. Conversely, the strength of the nonwoven fabric in the wet state is 110% of the strength of the nonwoven fabric in the dry state.
%, The degree of swelling of the nonwoven fabric in a wet state is strong, and the nonwoven fabric having elasticity shrinks due to swelling. , Which may be undesirable. That is, the nonwoven fabric of the present invention has excellent water absorption, and the strength of the nonwoven fabric when wet does not decrease, so that the nonwoven fabric can maintain its shape even when used in a wet condition. And a stretchable nonwoven fabric that can be used without selecting a nonwoven fabric. Therefore, the nonwoven fabric of the present invention,
For example, even when used for underwear, clothes, etc., even in a wet state due to perspiration, it can be used well without lowering the strength.

The stretchable nonwoven fabric of the present invention has a bulk density of 0.0
It is a nonwoven fabric in the range of 4 to 0.1 g / cc. That is, the nonwoven fabric of the present invention contains short fibers composed of polymers having different heat shrinkages, and since these short fibers have a three-dimensional crimp, the nonwoven fabric is excellent in bulkiness.

In the present invention, the basis weight of the nonwoven fabric subjected to the three-dimensional entanglement treatment by the high-pressure liquid flow is 30 to 100 g.
/ M ² . If the basis weight is less than 30 g / m ^2, it is difficult to improve the shape retention of the obtained web. Conversely, if the basis weight exceeds 100 g / m ² , not only the three-dimensional entanglement between the constituent fibers of the nonwoven web is not sufficiently obtained, but also when sufficient heat shrinkage is applied, sufficient crimping is not obtained. It is difficult to obtain a practically usable stretchable nonwoven fabric without manifestation or shrinkage of the nonwoven fabric area.

The stretchable nonwoven fabric of the present invention can be dyed or printed as necessary, or can be used by laminating with other materials as long as the stretchability is not impaired.
When used in a laminated form with other materials, for example, when used for a wiper or the like, although moisture is absorbed by the nonwoven web layer having water absorption, a nonwoven fabric that does not wet its hands for users In medical clothing, the surface layer functions as a water-repellent layer by arranging a nonwoven web layer made of synthetic short fibers made of polypropylene on the surface, and is a layer in contact with the skin. Functions as a water-absorbing agent, and can absorb the perspiration when used during perspiration.

Next, a method for producing a stretchable nonwoven fabric of the present invention will be described. First, by using two or more kinds of thermoplastic polymer components having different heat shrinkage, a shape in which the two or more kinds of thermoplastic polymer components are juxtaposed along the length direction of the yarn,
Synthetic short fibers having latent crimping properties such that the two or more thermoplastic polymer components have any of the shapes arranged in an eccentric sheath structure in the fiber cross section.

More specifically, as polymers having different heat shrinkages, for example, polypropylene and a copolymerized polypropylene obtained by copolymerizing a propylene polymer component with an ethylene polymer component at 2 to 8% are used as suitable materials. The spinning temperature is controlled via one of a spinneret forming a fiber cross section arranged in parallel in the yarn direction of the fiber and a spinneret forming a so-called eccentric core-sheath type composite cross section. Is usually 200 to 260 ° C. to perform melt spinning. After cooling the polymer stream spun from the spinneret,
An undrawn yarn is obtained at a speed of １1400 m / min, and a plurality of the undrawn yarns are combined and drawn to give a drawn yarn. Stretching is performed by a pair of stretching rolls having different peripheral speeds. Subsequently, the drawn fiber yarn is pushed into the crimper to guide it to a crimp, and then a spinning oil is applied, dried and cut to a predetermined fiber length to obtain a synthetic short fiber. Can be. When crimping the drawn yarn, the number of crimps is preferably 10 to 20 peaks / 25 mm. If it is less than 10 peaks / 25 mm, 20 peaks / 2
In any case exceeding 5 mm, in the card process,
This causes sinking of the single yarn into the cylinder and poor fibrillation, which tends to hinder productivity.

Next, the synthetic staple fiber and the water-absorbent fiber obtained by a conventional method are mixed at a ratio of synthetic staple fiber / water-absorbent fiber = 40/60 to 70/30 (% by weight). The nonwoven web is formed by defibrating, for example, using a carding machine. When blending both fibers, if the amount of the synthetic short fiber is less than 40% by weight based on the weight of the non-woven fabric, the area shrinkage generated in the non-woven fabric when the latent crimp is realized by performing the relaxation heat shrinkage treatment Tends to be insufficient. As the nonwoven web formed by the card machine, a parallel card web using a parallel card machine in which the fiber arrangement is uniform in the machine direction, and a fiber arrangement by using the parallel card machine and the cross layer in the machine direction are used. A cross-laid web laminated in the orthogonal direction, a web in which the fiber length / width arrangement of the cross-laid web is changed using a drafter, or a semi-random web using a semi-random card machine, or a fiber arrangement using a random card machine A non-uniform random card web and the like can be mentioned. Also, by combining a plurality of these card machines or using a plurality of card machines of the same type, the mechanical performance of the nonwoven fabric can be improved,
Operability and productivity can be improved.

Next, the obtained nonwoven web is subjected to a high-pressure liquid flow treatment to form a three-dimensional entanglement between the constituent fibers to maintain the form as a nonwoven fabric, and then subjected to a drying treatment.

In the present invention, when the nonwoven web is subjected to three-dimensional entanglement by the high-pressure liquid flow, the nonwoven web is placed on a moving porous support plate and, for example, the pore size is set to 0.05.
A large number of orifice heads arranged in one or a plurality of rows with injection holes of about 1.0 to 1.0 mm, preferably 0.08 to 0.4 mm, with a hole interval of 0.3 to 2 mm, and an injection pressure of 5 to 150 kg / cm A method of injecting a ² G high-pressure liquid stream from the injection hole is employed. The injection holes are preferably arranged in rows in a direction perpendicular to the direction of travel of the nonwoven web. The support material for supporting the nonwoven web is not particularly limited as long as the high-pressure liquid flow can pass through the nonwoven web, for example, a mesh screen such as a 20 to 100 mesh wire mesh or a perforated plate. Generally, water or hot water is used as the high-pressure liquid. The distance between the injection hole and the nonwoven web is 1
It is good to be 10 cm to 10 cm. If this distance is less than 1 cm, the formation of the nonwoven fabric obtained by this treatment is disturbed,
On the other hand, if the distance exceeds 10 cm, the impact force when the high-pressure liquid stream collides with the nonwoven web is reduced, and it is difficult to sufficiently perform three-dimensional confounding.

In the present invention, the high-pressure liquid flow treatment is preferably performed in at least two stages. First, as a process of the first stage, a high-pressure liquid stream having a pressure of 5 to 40 kg / cm ² G is jetted and collided with the nonwoven web to preliminarily entangle the constituent fibers of the nonwoven web. In the first stage treatment, if the pressure of the liquid flow is less than 5 kg / cm ² G, the constituent fibers of the nonwoven web cannot be preliminarily entangled, and conversely, the pressure of the liquid flow becomes 40 kg / cm ² G. / C
When the pressure exceeds m ² G, the constituent fibers of the nonwoven web are disturbed by the action of the liquid flow when the high-pressure liquid stream is jetted and collided with the nonwoven web, and the formation of the web tends to be disturbed or the basis weight is uneven. . Next, as a process of the second stage, the pressure exceeds 40 kg / cm ² G and the pressure exceeds 150 kg / cm ² G
A high-pressure liquid stream having a pressure higher than the pressure in the first stage is jetted to impinge on the nonwoven web, and the constituent fibers of the nonwoven web are three-dimensionally entangled, and the nonwoven web is integrated as a whole. Let it. In the treatment of the second stage, if the pressure of the liquid flow is 40 kg / cm ² G or less, it is not possible to sufficiently form three-dimensional entanglement between the fibers, and conversely, the pressure of the liquid flow is 150 kg / cm ² G. If it exceeds cm ² G, the resulting nonwoven fabric tends to lack flexibility and bulkiness. As described above, the pressure in the second stage treatment is 40 to 150 kg / cm.
A high-pressure liquid stream of ² G is used. In this case, the constituent fibers of the nonwoven web are preliminarily entangled with each other by the first-stage treatment. The web is not disturbed by the action of the liquid flow, and the web is not disturbed by formation or spots. Further, after performing the entanglement treatment by the above-described method, the nonwoven web is again inverted, and the entanglement treatment is similarly performed from the opposite surface, whereby a nonwoven fabric integrated with both sides can be obtained.

In the present invention, after the high-pressure liquid flow treatment is performed, the drying treatment is performed. At this time, first, excess moisture is removed from the treated nonwoven web. To remove this excess water,
A known method can be adopted. For example, excess water is mechanically removed to some extent using a squeezing device such as a mangle roll. Then, the remaining moisture is removed using a drying device such as a continuous hot-air dryer to obtain a nonwoven web whose shape is maintained by three-dimensional entanglement.

In the present invention, the three-dimensionally entangled nonwoven web thus obtained is subsequently subjected to a latent crimp by relaxation heat shrinkage treatment, and further subjected to area shrinkage processing as a nonwoven fabric. is important. Synthetic short fibers as described above have latent crimping properties due to their special fiber shape and the difference in shrinkage of their constituent components, and crimps are developed by relaxation heat shrinkage treatment. The manifestation appears as an area shrinkage in the nonwoven fabric, and improves the stretchability of the nonwoven fabric due to the shrinkage of the area expressed in the nonwoven fabric.

In the present invention, when the relaxation heat shrinkage treatment is performed, the melting point of the polymer component having the lowest melting point among the thermoplastic polymer components constituting the synthetic short fiber having latent crimpability is defined as Tm ° C. In addition, (Tm−30) ° C. to (Tm +
10) Treat at a temperature of ° C. If the temperature of the relaxation heat shrinkage treatment is lower than (Tm-30) ° C., it is not preferable because sufficient crimping cannot be obtained due to the appearance of latent crimp of the polymer component constituting the nonwoven fabric. Also (Tm + 10)
When the temperature exceeds ℃, the low-melting-point polymer is fused, so that the flexibility of the obtained nonwoven fabric is impaired and the elasticity is impaired.

An important point of the relaxation heat shrinkage treatment in the present invention is that the nonwoven fabric exhibits a sufficient shrinkage and has a substantially elasticity. That is, a sufficient amount of heat may be applied to the nonwoven web, and the blowing air amount may be set within a range where the temperature does not decrease or increase, and the suction amount may be slightly lower than the blowing air amount. Further, in order to sufficiently reduce the longitudinal shrinkage of the nonwoven web, the nonwoven web may be supplied at an earlier speed than the moving speed of the net.

In the relaxation heat shrinkage treatment, it is preferable to use a heat treatment machine that does not apply tension to the nonwoven web. As a heat treatment machine of this type, a shrinkage dryer in which hot air blows from both sides to the nonwoven web is preferable and generally used. As the shrinkage dryer, a shrink safar manufactured by Hirano Techseed, a Lucior manufactured by Kyoto Kikai Kogyo, a shrink dryer manufactured by Kotobuki Kogyo, etc. can be preferably used. Also, shrinkage can be generated even by using a suction band type heat treatment machine. In this case, the amount of air to be blown out and the amount of air to be sucked are regulated, and by adding no extra amount of air to the nonwoven web, heat can be added to cause shrinkage.

[0051]

Next, the present invention will be specifically described based on examples, but the present invention is not limited to only these examples. Incidentally, the measurement of various characteristic values in the examples,
It carried out by the following method.

(1) Melting point (° C.): Using a differential scanning calorimeter (manufactured by PerkinElmer; DSC-2 type), heating rate 2
The measurement was performed under the condition of 0 ° C./min, and the temperature at which an extreme value was obtained in the obtained melting endothermic curve was defined as the melting point (° C.).

(2) Melt flow rate value (g / 10
Min): Measured according to the method described in ASTM-D-1238 (L) (hereinafter, the MFR value is referred to as a melt flow rate value).

(3) Relative viscosity: The relative viscosity of polyethylene terephthalate was measured by the following method. That is, 0.5 g of a sample was dissolved in 100 cc of the solvent using a mixed solution of an equal weight of phenol and ethane tetrachloride as a solvent.

(4) Fabric weight of nonwoven fabric (g / m ² ): Ten sample pieces each having a sample length of 10 cm and a sample width of 10 cm were prepared from the sample in the standard state, and the water content was adjusted to equilibrium moisture. g) was weighed, and the average of the obtained values was converted per unit area to give the basis weight (g / m ² ).

(5) Tensile strength of nonwoven fabric (kg / 5cm
Width) and elongation at break (%): Measured according to the method described in JIS-L-1096A. That is, using a non-woven fabric in a dry state, sample pieces each having a sample length of 15 cm and a sample width of 5 cm are prepared in the machine direction (MD) and the direction (CD) orthogonal to the non-woven fabric by 10 points each. For the MD direction and the CD direction of the nonwoven fabric, the gripping interval of the sample was set to 10 using a constant-speed extension-type tensile tester (manufactured by Toyo Baldwin Co., Ltd .; Tensilon UTM-4-1-100).
cm and stretched at a tensile speed of 10 cm / min. And
The average value of the obtained load values at cutting (kg / 5 cm width) was defined as the tensile strength (kg / 5 cm width), and the average value of the elongation rate at cutting (%) was defined as the elongation at break (%). Regarding the strength of the nonwoven fabric in the wet state (kg / 5 cm width), the nonwoven fabric in the dry state is 50 to 30% based on the weight of the nonwoven fabric.
After adding 0% by weight of water, the measurement was carried out by the same measuring method as described above.

(6) Area shrinkage (%): sample length is 20c
m, a total of five sample pieces having a sample width of 20 cm were prepared, and each sample piece was subjected to a heat treatment for 5 minutes using an air oven type heat treatment machine at a predetermined temperature. Then, the area S1 (cm ² ) value of the sample piece before the heat treatment and the area S2 of the sample piece after the heat treatment
Using the (cm ² ) value, the average value of the shrinkage ratio (%) calculated according to the following equation was defined as the area shrinkage ratio (%).

Area shrinkage (%) = [1− (S2 / S1)] × 100

(7) Flexural softness (g): sample length is 10c
m, a total of five sample pieces each having a sample width of 5 cm were prepared, and each sample piece was bent in the lateral direction to form a cylindrical object, and the end of each was joined to obtain a compression-hardness measurement sample. For each measurement sample, in the axial direction, a constant-speed extension-type tensile tester (manufactured by Toyo Baldwin Co., Ltd .; Tensilon UTM-4-1-100)
And compression was performed at a compression speed of 5 cm / min, and the average value of the obtained maximum load values (g) was defined as the compression stiffness (g). In addition,
The smaller the value of the compression stiffness, the higher the flexibility.

(8) Elongation elastic recovery rate (%): sample width 5c
m, a sample piece having a sample length of 15 cm was prepared in the machine direction of the nonwoven fabric and in a direction perpendicular to the nonwoven fabric respectively, and a constant-speed stretching tensile tester (manufactured by Toyo Baldwin Co .; Tensilon U)
TM-4-1-100) and JIS-L-1096
In accordance with the method described in 6.13.1A, for each sample, the sample piece is pulled at a speed of 10 cm / min at a sample gripping interval of 10 cm, and the recovery elongation to a constant elongation when the elongation reaches 30%. And the average value was taken as the elongation recovery rate (%).

(9) Water absorption (mm / 10 minutes): JIS-
It was measured according to the Bilek method described in L-1096.

(10) Evaluation of whiteness: Evaluation was carried out by 10 panelists, and the results were evaluated in five levels. The five-grade evaluation is shown below. 5 Has excellent whiteness.

4 Good whiteness. 3 Has whiteness. 2 Whiteness is unclear.

1 Whiteness is not felt.

Example 1 Polypropylene having an MFR value of 40 g / 10 min and a melting point of 160 ° C. was copolymerized with 4% by weight of an ethylene polymer component to a propylene polymer component. The MFR value was 27 g / 10 min and the melting point was 136 ° C. Synthetic short fibers having latent crimpability were produced using copolymerized polypropylene and a composite ratio of both polymer components at a weight ratio of 1: 1. That is, by setting the ratio of the MFR value of the polypropylene and the copolymerized polypropylene to 1.5, these two polymer components are melted at a temperature of 230 ° C., and a composite spinneret capable of forming a fiber cross-sectional shape shown in FIG. Spinning was performed with a single hole discharge rate of 0.79 g / min. The polymer stream spun from the spinneret was cooled and taken off at a speed of 1100 m / min to obtain an undrawn yarn.
A plurality of the unstretched yarns were combined and stretched at a draw ratio of 3.5 using a stretching machine. Then, the stretched yarn was pushed into the crimper to give a crimp of 14 ridges / 25 mm, then a spinning oil was applied, dried, and cut. The obtained synthetic short fibers had a shape in which polypropylene and copolymerized polypropylene were laminated in parallel so as to be exposed in the yarn direction of the fibers, and had a single yarn fineness of 2 denier and a fiber length of 51 mm.

On the other hand, as the water-absorbing fiber, bleached cotton having an average fineness of 1.7 denier and an average fiber length of 24 mm is used, and the synthetic staple fiber and the cotton fiber are combined with a synthetic staple fiber / cotton fiber = 70. / 30 (% by weight), and a random carding machine was used to prepare a nonwoven web having a basis weight of 72 g / m ² in which the fiber arrangement was not uniform.

The obtained nonwoven web was placed on an 80-mesh metal net moving at a speed of 20 m / min, and the hole diameter was 0.1 mm from a position 30 mm above the nonwoven web.
The first stage of pre-entanglement was performed with a high-pressure liquid flow having an injection pressure of 40 kg / cm ² G using an orifice head in which the injection holes were arranged in a line at an interval of 0.6 mm. Subsequently, using the same orifice head as above, the injection pressure was 70 kg / c.
The treatment was performed four times with m ² G to obtain a second-stage confounding treatment.

The resulting treated product was obtained by entanglement of the synthetic short fibers and cotton fibers constituting the nonwoven web to be densely integrated. Excess moisture was removed from the entangled nonwoven web using a mangle, which is a known moisture removing device, and subsequently dried at 90 ° C. using a suction band type dryer.

Next, the nonwoven web subjected to the drying treatment was subjected to heat shrinkage. When performing the shrinkage processing, a relaxation heat shrinkage processing machine (manufactured by Kyoto Kikai Co., Ltd .; trade name: Luciol) is used, and the relaxation heat shrinkage treatment temperature is 12 ° C. lower than the melting point of the low melting point component constituting the synthetic short fiber. ° C. Non-woven fabric subjected to relaxation heat shrinkage treatment
Shrinkage of 2% and 30% in the direction perpendicular to the machine direction occurred, and the area shrinkage was 49%. Table 1 shows the performance of the obtained nonwoven fabric. The strength of the wet nonwoven fabric was measured by adding 100% by weight of water to the weight of the nonwoven fabric.

The obtained non-woven fabric is a non-woven fabric in which shrinkage has occurred in both the vertical and horizontal directions, that is, one in which latent crimp has become apparent, has excellent stretchability, has excellent mechanical properties, and has excellent flexibility. Rich and show good water absorption,
Even in a wet state, the nonwoven fabric had practicality with no decrease in strength.

[0071]

[Table 1]

Example 2 Polypropylene having an MFR value of 20 g / 10 minutes and a melting point of 160 ° C. was copolymerized with 3% by weight of an ethylene polymer component to a propylene polymer component. The MFR value was 14 g / 10 minutes and the melting point was 142 ° C. These copolymer components are melted at a temperature of 250 ° C. using a copolymerized polypropylene, and the single hole discharge amount is adjusted to 0.1.
Spinning was performed at a rate of 74 g / min, the draw ratio was set to 3.3 times, and a crimp of 12 threads / 25 mm was provided. Otherwise in the same manner as in Example 1, a synthetic short fiber having latent crimpability was produced. The ratio of the MFR value between the polypropylene and the copolymerized polypropylene was 1.4. The obtained synthetic short fiber has a shape in which polypropylene and copolymerized polypropylene are bonded in parallel in the fiber yarn direction so that both components are exposed in the fiber yarn direction, and the single yarn fineness is 2.0 denier. The fiber length was 44 mm.

On the other hand, as the fiber having water absorbability, lyocell (a denier of 1.7, denier: 1.7 mm, fiber length: 44 mm) which is a solvent-spun rayon fiber was used. Lyocell = 50/5
The mixture was uniformly mixed at a ratio of 0 (% by weight), and a nonwoven web having a basis weight of 76 g / m ² was prepared using a random card machine.

Next, the obtained non-woven web was subjected to Example 1
In the same manner as described above, the high-pressure liquid flow treatment and the subsequent relaxation heat shrinkage treatment were performed. The processing temperature was 130 ° C.
Table 1 shows the performance of the obtained nonwoven fabric. The strength of the wet nonwoven fabric was measured by adding 50% by weight of water to the weight of the nonwoven fabric.

The obtained nonwoven fabric was excellent in elasticity in both the vertical and horizontal directions, had excellent mechanical properties, was highly flexible, and had good water absorption. The strength of the nonwoven fabric in a wet state is 9% of the strength in a dry state.
It was a good nonwoven fabric showing 4%.

Example 3 Synthetic short fibers were obtained with the eccentric core-sheath composite cross section shown in FIG. 2 as the cross section of the synthetic short fibers. That is, the MFR value is 27 g
/ 10 min, polypropylene having a melting point of 160 ° C. is used as a core component which is eccentrically arranged, and an MFR value obtained by copolymerizing a propylene polymer component with an ethylene polymer component at 4% by weight is 40 g / 1.
A composite spinneret capable of forming an eccentric core-sheath type fiber cross-sectional shape shown in FIG. 2 using a copolymer polypropylene having a melting point of 136 ° C. for 0 minutes as a sheath component was used. Otherwise in the same manner as in Example 1, a synthetic short fiber was obtained. The obtained synthetic short fiber was an eccentric core-sheath type composite fiber having a single yarn fineness of 2 denier and a fiber length of 51 mm. On the other hand, a viscose rayon fiber obtained from pulp having a single yarn fineness of 1.5 denier and a fiber length of 44 mm was used as the water-absorbing fiber, and the synthetic staple fiber and the rayon fiber were synthesized as synthetic staple fiber / rayon fiber = 60/40
(Weight%), and a random carding machine was used to prepare a nonwoven web having a basis weight of 77 g / m ² with an uneven fiber arrangement.

Next, the obtained nonwoven web was subjected to a high-pressure liquid flow treatment and a subsequent relaxation heat shrinkage treatment in the same manner as in Example 1. Table 1 shows the performance of the obtained nonwoven fabric. The strength of the wet nonwoven fabric was measured by adding 100% by weight of water to the weight of the nonwoven fabric.

The obtained nonwoven fabric has good elasticity,
In addition, it is a stretchable non-woven fabric having excellent mechanical properties, rich in flexibility, without a decrease in the strength of the non-woven fabric in a wet state, and having good water absorption, in any of a dry state and a wet state. Could be used well.

Example 4 Synthetic staple fiber and cotton fiber were synthesized as follows: synthetic staple fiber / cotton fiber = 4
The mixture was uniformly mixed at a ratio of 0/60 (% by weight). Otherwise in the same manner as in Example 1, a nonwoven fabric was obtained. Table 1 shows the performance of the obtained nonwoven fabric. The strength of the wet nonwoven fabric is
The measurement was carried out by adding 300% by weight of water to the weight of the nonwoven fabric.

The obtained nonwoven fabric is excellent in elasticity in both the longitudinal and transverse directions, has excellent mechanical properties, is rich in flexibility, has good water absorption, and is sufficiently wet. It had strong power.

Example 5 A propylene polymer having an MFR value of 14 g / 10 minutes and a melting point of 160 ° C. was copolymerized with a propylene polymer component and an ethylene polymer component at 4% by weight. The MFR value was 20 g / 10 minutes.
A copolymerized polypropylene having a melting point of 136 ° C. was used, and the composite ratio of both polymer components was set to a weight ratio of 1: 1.
Melt spinning was performed at a temperature of 0 ° C. In melt spinning,
Spinning holes capable of forming the fiber cross-sectional shape shown in FIG. 2 were provided. Using a composite spinneret, the single hole discharge rate was 0.74 g /
Min, the spinning speed was 1100 m / min, and the draw ratio was 3.3 times. The resulting synthetic staple fiber has a single yarn fineness of 2.0 denier,
The eccentric core-sheath composite fiber had a fiber length of 51 mm, the copolymerized polypropylene was a sheath component, the polypropylene was a core component, and the polypropylene of the core component was eccentrically arranged in the fiber cross section.

As the water-absorbing fiber, a cotton anti-hair fiber subjected to a fluorescent treatment was used. This cotton anti-hair fiber is made from cut pieces generated in the process of producing a knitted undergarment that has been subjected to a fluorescent treatment, and has an average denier of 1.8 denier and an average fiber length of 16 mm obtained at an anti-hair ratio of 65%. Wool fibers were used.

The ratio of the synthetic staple fibers and the cotton woolen fibers was uniformly mixed with the ratio of synthetic staple fibers / cotton woolen fibers = 70/30, and the basis weight of the fibers was not uniform, 85 g / m 2.
² random card webs were created. Next, the obtained nonwoven web was placed on a 70-mesh metal net moving at a speed of 20 m / min, and the orifices having a diameter of 0.1 mm were arranged in a row at a hole interval of 0.6 mm. Using a head, a first stage of pre-entanglement treatment was performed from a position 50 mm above the nonwoven web with a high-speed liquid flow having an injection pressure of 40 kg / cm ² G. Subsequently, using the above-mentioned orifice head, a treatment was performed four times at an injection pressure of 70 kg / cm ² G to obtain a second stage of entanglement treatment.

The resulting treated product was a nonwoven web having three-dimensional entanglement in which fibers constituting the nonwoven web were entangled with each other and densely integrated. Excess water was removed from the nonwoven web subjected to the entanglement treatment with a mangle, which is a known moisture removal device, and then dried at 90 ° C. using a suction band type dryer.

Next, the dried non-woven web was subjected to heat shrinkage. When performing the relaxation heat shrinking process, a shrinkage dryer (Kyoto Kikai Kogyo Co., Ltd .; trade name: Luciol) is used, and the processing temperature is set to 124.
C. and a processing speed of 20 m / min. However, the supply speed of the nonwoven web with respect to the processing speed was 23.5 m / min.
Table 2 shows the performance of the obtained nonwoven fabric.

The obtained nonwoven fabric is a stretchable nonwoven fabric having excellent mechanical properties, high flexibility, excellent stretchability in both the longitudinal and transverse directions, and good water absorption and whiteness. Was.

[0087]

[Table 2]

Example 6 As a synthetic short fiber having latent crimpability, a short fiber composed of a polyester polymer was used. That is, polyethylene terephthalate (hereinafter, referred to as PET) having a melting point of 256 ° C. and a relative viscosity of 1.30, and 5.1 mol% of 5-sodium sulfoisophthalic acid copolymerized with PET,
Using a copolymerized polyester having a melting point of 232 ° C. and a relative viscosity of 1.45, the composite ratio of both polymer components was 1: 1 by weight.
As a percentage, a synthetic short fiber having latent crimpability was produced. These two polymer components were melted at a temperature of 295 ° C., and the single hole discharge amount was set to 0.7 using the same composite spinneret as in Example 1.
Spinning was performed at 0 g / min. The polymer stream spun from the spinneret is cooled and taken off at a speed of 1100 m / min.
An undrawn yarn was obtained. A plurality of the unstretched yarns were combined and stretched at a draw ratio of 3.0 using a stretching machine.
Then, the stretched yarn was pushed into the crimper to apply a crimp of 15 ridges / 25 mm. Then, a spinning oil was applied, dried, and cut. The obtained synthetic staple fiber had a shape in which both components of the polyester and the copolyester were laminated in parallel in the fiber yarn direction so as to be exposed, and had a single yarn fineness of 2 denier and a fiber length of 51 mm.

On the other hand, as the water-absorbing fiber, lyocell (a denier of 1.7 denier, fiber length of 44 mm), a solvent-spun rayon fiber, was used. Lyocell = 50/5
The mixture was uniformly mixed at a ratio of 0 (% by weight), and a nonwoven web having a basis weight of 78 g / m ² with an uneven fiber arrangement was prepared using a random card machine.

Next, when the obtained nonwoven web was subjected to the relaxation heat shrinkage treatment, the treatment temperature was set to 210 ° C. Otherwise, in the same manner as in Example 1, a high-pressure liquid flow treatment and subsequently a relaxation heat shrinkage treatment were performed. Table 2 shows the performance of the obtained nonwoven fabric. The strength of the wet nonwoven fabric was measured by adding 100% by weight of water to the weight of the nonwoven fabric.

The obtained non-woven fabric was a stretchable non-woven fabric having excellent mechanical properties, excellent flexibility, excellent stretchability in both the longitudinal and transverse directions, and good water absorption.

Comparative Example 1 Synthetic staple fiber and cotton fiber were synthesized as follows: synthetic staple fiber / cotton fiber = 2
The mixture was uniformly mixed at a ratio of 5/75 (% by weight). Otherwise in the same manner as in Example 1, a nonwoven fabric was obtained. Table 3 shows the performance of the obtained nonwoven fabric. The strength of the wet nonwoven fabric is
The measurement was carried out by adding 100% by weight of water to the nonwoven fabric.

The obtained nonwoven fabric was excellent in water absorbency and nonwoven fabric strength in a wet state, but was poor in elasticity.

[0094]

[Table 3]

Comparative Example 2 A synthetic staple fiber and a cotton fiber were mixed with a synthetic staple fiber / cotton fiber = 7.
The mixture was uniformly mixed at a ratio of 5/25 (% by weight). Otherwise in the same manner as in Example 1, a nonwoven fabric was obtained. Table 3 shows the performance of the obtained nonwoven fabric. The strength of the wet nonwoven fabric is
The measurement was carried out by adding 100% by weight of water to the nonwoven fabric.

Although the obtained nonwoven fabric has good stretchability, it has poor water absorption, and the strength of the nonwoven fabric in a wet state is 55.8% of that in a dry state. , The nonwoven fabric itself was low in strength and poor in practicality.

Comparative Example 3 A non-woven fabric was obtained in the same manner as in Example 1 except that the heat treatment temperature was changed to 100 ° C. Table 3 shows the performance of the obtained nonwoven fabric.
The strength of the nonwoven fabric in the wet state is 10% with respect to the weight of the nonwoven fabric.
The measurement was carried out by adding 0% by weight of water.

The obtained nonwoven fabric was a nonwoven fabric which did not exhibit the area shrinkage expected in the present invention because the temperature of the relaxation heat shrinkage treatment was too low, and was inferior in elasticity. The bulk density was also 0.038, which was less than the value expected in the present invention.

[0099]

According to the present invention, two or more kinds of thermoplastic polymers having different heat shrinkages are formed, and the two or more kinds of thermoplastic polymer components are arranged side by side along the length direction of the yarn. A synthetic short fiber having a latent crimping property in any one of a set shape and a shape in which the two or more kinds of thermoplastic polymer components are arranged in an eccentric core-sheath structure in a fiber cross section is a nonwoven fabric; The synthetic staple fiber having a latent crimpability is contained in an amount of 40 to 70% by weight based on the weight, and the latent crimp is evident. An elastic nonwoven fabric can be obtained.

According to the present invention, together with the synthetic staple fiber, the water-absorbing fiber is 60 to 30% by weight based on the weight of the nonwoven fabric.
Since it is contained by weight, a stretchable nonwoven fabric having excellent water absorbability can be obtained.

Furthermore, since the nonwoven fabric of the present invention retains its shape by three-dimensional entanglement between constituent fibers, the nonwoven fabric has sufficient mechanical properties for practical use and also has high flexibility. .

[Brief description of the drawings]

FIG. 1 is a fiber cross-sectional model diagram of an example of a synthetic short fiber suitable for the present invention.

FIG. 2 is a fiber cross-sectional model diagram of another example of a synthetic short fiber suitable for the present invention.

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[Procedure amendment]

[Submission date] December 5, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction contents]

More specifically, as polymers having different heat shrinkages, for example, polypropylene and a copolymerized polypropylene obtained by copolymerizing a propylene polymer component with an ethylene polymer component at 2 to 8% are used as suitable materials. The spinning temperature is controlled via one of a spinneret forming a fiber cross section arranged in parallel in the yarn direction of the fiber and a spinneret forming a so-called eccentric core-sheath type composite cross section. Is usually 200 to 260 ° C. to perform melt spinning. After cooling the polymer stream spun from the spinneret,
An undrawn yarn is obtained at a speed of about 1400 m / min, and a plurality of the undrawn yarns are combined and drawn to give a drawn yarn. Stretching is performed by a pair of stretching rolls having different peripheral speeds. Subsequently, the drawn fiber yarn is pushed into the crimper to guide it to a crimp, and then a spinning oil is applied, dried and cut to a predetermined fiber length to obtain a synthetic short fiber. Can be.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0065

[Correction method] Change

[Correction contents]

Example 1 Polypropylene having an MFR value of 40 g / 10 min and a melting point of 160 ° C. was copolymerized with 4% by weight of an ethylene polymer component to a propylene polymer component. The MFR value was 27 g / 10 min and the melting point was 136 ° C. Synthetic short fibers having latent crimpability were produced using copolymerized polypropylene and a composite ratio of both polymer components at a weight ratio of 1: 1. That is, by setting the ratio of the MFR value of the polypropylene and the copolymerized polypropylene to 1.5, these two polymer components are melted at a temperature of 230 ° C., and a composite spinneret capable of forming a fiber cross-sectional shape shown in FIG. Spinning was performed with a single hole discharge rate of 0.79 g / min. The polymer stream spun from the spinneret was cooled and taken off at a speed of 1100 m / min to obtain an undrawn yarn.
A plurality of the unstretched yarns were combined and stretched at a draw ratio of 3.5 using a stretching machine. Then, the stretched yarn was pushed into the crimper and crimped. Then, a spinning oil was applied, dried, and cut. The obtained synthetic short fibers had a shape in which polypropylene and copolymerized polypropylene were laminated in parallel so as to be exposed in the yarn direction of the fibers, and had a single yarn fineness of 2 denier and a fiber length of 51 mm.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0088

[Correction method] Change

[Correction contents]

Example 6 As a synthetic short fiber having latent crimpability, a short fiber composed of a polyester polymer was used. That is, polyethylene terephthalate (hereinafter referred to as PET) having a melting point of 256 ° C. and a relative viscosity of 1.30, and 5.1 mol% of 5-sodium sulfoisophthalic acid copolymerized with PET,
Using a copolymerized polyester having a melting point of 232 ° C. and a relative viscosity of 1.45, the composite ratio of both polymer components was 1: 1 by weight.
As a percentage, a synthetic short fiber having latent crimpability was produced. These two polymer components were melted at a temperature of 295 ° C., and the single hole discharge amount was set to 0.7 using the same composite spinneret as in Example 1.
Spinning was performed at 0 g / min. The polymer stream spun from the spinneret is cooled and taken off at a speed of 1100 m / min.
An undrawn yarn was obtained. A plurality of the unstretched yarns were combined and stretched at a draw ratio of 3.0 using a stretching machine.
Then, the stretched yarn was pushed into the crimper and crimped. Then, a spinning oil was applied, dried, and cut. The obtained synthetic staple fiber had a shape in which both components of the polyester and the copolyester were laminated in parallel in the fiber yarn direction so as to be exposed, and had a single yarn fineness of 2 denier and a fiber length of 51 mm.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Michiyo Iimi 23 Uji Kozakura, Uji City, Kyoto Prefecture Unitika's Central Research Laboratory

Claims (8)

[Claims] 1. A synthetic staple fiber composed of two or more thermoplastic polymer components having different heat shrinkages and a water-absorbent fiber are defined as synthetic staple fiber / water-absorbent fiber = 40/6.
0 to 70/30 (% by weight), wherein the synthetic short fibers have a shape in which the two or more thermoplastic polymer components are arranged side by side along the length direction of the yarn. A latent crimpable fiber having any one of the two or more thermoplastic polymer components and a shape arranged in an eccentric core-sheath structure in a cross section of the fiber; The crimp is manifested, the constituent fibers of the nonwoven fabric are retained in shape by having three-dimensional confounding with each other, and the stretch elastic recovery at 30% elongation of the nonwoven fabric is 80% or more. Stretch nonwoven. 2. The non-woven fabric has a water absorption of at least 35 mm / 10 minutes as measured by a birec method and a bulk density of 0.0
The stretchable nonwoven fabric according to claim 1, wherein the content is in the range of 4 to 0.1 g / cc. 3. A synthetic staple fiber comprising: polypropylene; and a propylene polymer component containing 2 to 8% by weight of an ethylene polymer component.
The stretchable nonwoven fabric according to claim 1 or 2, comprising a copolymerized polypropylene. 4. The fiber having a water-absorbing property is cotton, linen,
The stretchable nonwoven fabric according to any one of claims 1 to 3, wherein the stretchable nonwoven fabric is any one of natural fibers selected from ramie, wool, and silk cut into short fibers. 5. The recycled fiber according to claim 1, wherein the water-absorbing fiber is any one of viscose rayon, cuprammonium rayon, and solvent-spun rayon.
4. The stretchable nonwoven fabric according to any one of items 1 to 3. 6. The fiber according to claim 1, wherein the water-absorbing fiber is a pliant fiber obtained from a cotton that has been subjected to a fluorescent treatment, and the nonwoven fabric has whiteness. The stretchable nonwoven fabric according to the above item. 7. A shape in which two or more kinds of thermoplastic polymer components having mutually different heat shrinkages are used and two or more kinds of thermoplastic polymer components are juxtaposed along the length direction of the yarn. And obtaining a synthetic short fiber having a latent crimping property so that the two or more thermoplastic polymer components have any of the shapes arranged in the eccentric sheath structure in the fiber cross section, The synthetic staple fiber and the water-absorbent fiber are mixed at a ratio of synthetic staple fiber / water-absorbent fiber = 40/60 to 70/30 (% by weight) and defibrated to form a nonwoven web. Formed, and then subjected to a high-pressure liquid flow treatment on the nonwoven web to form three-dimensional entanglement between the constituent fibers to maintain the form as a nonwoven fabric, followed by a drying treatment, followed by a relaxation heat shrinkage treatment The latent crimp becomes apparent by applying A method for producing a stretchable nonwoven fabric, which comprises causing shrinkage and imparting stretchability. 8. The relaxation heat shrinkage treatment is carried out when the melting point of the polymer component having the lowest melting point among the thermoplastic polymer components constituting the synthetic short fiber having latent crimpability is defined as Tm ° C.
The method for producing a stretchable nonwoven fabric according to claim 7, wherein the method is performed at a temperature of -30) C to (Tm + 10) C.