JPS6316504B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel nonwoven fabric made of long fibers of thermoplastic organic composite, which is extremely flexible and has excellent practical properties, and a method for producing the same.
More specifically, the nonwoven fabric is made of heat-crimpable conjugate long fibers of a thermoplastic organic composite, and the shape of the non-woven fabric is maintained not by adhesives or heat fusion bonding, but by substantially entangling the fibers. A nonwoven fabric that is flexible, has excellent elasticity, tensile strength at break, tear strength, abrasion resistance, a uniform surface, and a luxurious feel, and a method for producing the same. In recent years, the development of nonwoven fabrics has progressed and a variety of nonwoven fabrics have been provided, and in particular, long fiber nonwoven fabrics obtained by the spunbond method are attracting attention as promising nonwoven fabrics due to their excellent physical properties and high productivity. Spunbond is made of thermoplastic organic composite.
It is a nonwoven fabric that is made by forming a continuous filament web by pulling yarns discharged from a number of nozzles in a molten state by high-speed air currents and dispersing them on a net conveyor, etc., which retains its shape. Most commonly, form-retaining spunbond uses an adhesive resin (so-called binder) between the fibers.
This is a non-woven fabric bonded with an emulsion (usually applied as an emulsion), but the cost of applying adhesive and subsequent drying is high, the binder deteriorates or elutes when used as a non-woven fabric, and it is also difficult to use a flexible non-woven fabric. However, in order to do so, it has disadvantages such as the need to use a special adhesive resin and a special adhesive application method, and in recent years, spunbond that does not use adhesive has been actively developed. . As a so-called binder-free spunbond material that does not use an adhesive resin, a heat-seal bonded nonwoven fabric is known. This spunbond fabric made by thermal fusion bonding is a nonwoven fabric made by heating a continuous filament web and fusion bonding some of the filaments. This non-woven fabric has bonding points created by heat-sealing, and since the degree of freedom is completely lost at the bonding points, it is significantly harder and has less volume than ordinary woven or knitted fabrics. . For this purpose, various methods have been proposed to improve the flexibility of thermally bonded nonwoven fabrics, such as mixing low melting point fibers or using fibers with a low melting point component in part or all of the surface layer. , methods of adjusting the density and adhesion state of the bonding points, mixing crimped fibers to increase the degree of freedom between the bonding points, and latent crimping in which a low-melting point component is placed in at least a part of the surface layer. A method has been proposed in which a low-melting point component is used as an adhesive component by mixing compressible fibers to cause crimp. However, no matter which of these methods is used, spunbond bonded by thermal fusion bonding is paper-like and does not reach the flexibility of cloth. Also known is a spunbond fabric that does not use an adhesive resin and maintains its shape by entangling the fibers with mechanical force. This typical nonwoven fabric is a nonwoven fabric whose fibers are entangled using a needle punch machine. In general, nonwoven fabrics intertwined by needle punching have less loss of freedom at joints than nonwoven fabrics bonded by heat-sealing, and can be finished more flexibly. However, conventional needle-punched nonwoven fabrics
In order to increase the tensile strength and prevent surface fuzz, it is necessary to increase the needle density, which has the problem of reducing productivity, and increasing the needle density too much may cause fiber breakage. This has the disadvantage that there is a limit to the tensile strength due to a decrease in strength, there is almost no elasticity, and sufficient physical properties cannot be obtained. In particular, long-fiber nonwoven fabrics obtained by the spunbond method cannot be put to practical use unless the needling effect is improved by increasing the basis weight or making the fineness of the long fibers extremely thick. However, this kind of spunbond is far from having a cloth-like feel, has insufficient tensile strength and elasticity, and has noticeable needle marks, so it is inferior in quality as a nonwoven fabric, and can only be used for special purposes. The problem is that it cannot be done. In addition, a technique has been proposed in which a crimped fiber web is produced using a spunbond method and then subjected to needle punching to obtain a flexible nonwoven fabric. That is, as in Japanese Patent Application Laid-Open No. 49-2975, crimps are made apparent by loosening after spinning and pulling, and the web is accumulated and needle punched. However, this method has the problem that it is difficult to open and uniformly disperse a continuous filament in which crimped loops are exposed, and that spinning cannot be drawn at high speed. Furthermore, since crimping has already occurred when the continuous filament is deposited as a web, although the sheet is bulky, there is almost no entanglement between the fibers due to crimping, and its shape is maintained only by the entanglement by needling. Therefore, in order to satisfy the tensile strength and surface abrasion resistance, it is necessary to increase the needle density of the needle punch, and the interlacing effect due to crimping between fibers is not exerted, and it is difficult to intertwine by needling. The crimping of the composite fiber is due to the difference in the tensile cycle rate, so the crimping loop is unstable, and the crimps arranged in the thickness direction by the needle are easily removed, resulting in poor stretching cycle properties. It also has the problem of poor strength, tear strength, and surface abrasion resistance. Furthermore, this nonwoven fabric has the disadvantage that needle marks are easily noticeable, so it cannot be used for general purposes. In view of these points, the present inventors have developed a fabric that is bulky and extremely flexible, has the texture of a woven or knitted fabric, has excellent elasticity, high tensile strength at break, high tear strength, and abrasion resistance. As a result of intensive studies to obtain a spunbond material with a uniform surface and a high-quality appearance, the present invention was completed. That is, the nonwoven fabric of the present invention is a nonwoven fabric made of long fibers made of eccentric conjugate fibers of a thermoplastic organic synthetic polymer exhibiting thermal crimpability with visible crimping, wherein (a) the conjugate fibers are The conjugate fiber has an average number of crimps of 10 or more per inch, (b) includes the conjugate fiber that becomes an interlaced fiber bundle penetrating in the thickness direction of the nonwoven fabric, and (c) the conjugate fiber is a penetrating entangled fiber bundle. , has a higher degree of coiled crimp in the part penetrated and exposed to the surface layer,
A long-fiber nonwoven fabric whose shape is maintained by three-dimensional entanglement, characterized by a fluff-like or fluffy state that is pressed against the surface of the nonwoven fabric, and a steric hindrance to thread removal. be. Furthermore, in the method for producing a nonwoven fabric of the present invention, in the production of a long fiber nonwoven fabric, (a) at least one component is a thermoplastic organic synthetic polymer capable of forming fibers, and the other components are heat-shrinkable. At least two components, which are thermoplastic organic synthetic polymers with different abilities, are melted and discharged so that they are arranged eccentrically in the fiber cross section, and the spinning speed is 4000~4000~
8,000 m/min to form a latent heat-crimpable conjugate fiber, which is made into a continuous filament web; (c) subjecting the continuous filament web to a heat treatment that reduces the fiber shrinkage rate at low temperature by at least 2% while maintaining the crimp shrinkage rate of the composite fibers at a low temperature of 20% or more; (d) needle-punching the heat-treated continuous filament web from only one side or from both sides at a needle density of 5 to 100 P/cm ² per side and a needle depth capable of producing penetrating entangled fiber bundles; The punched web is characterized in that the composite fibers are made to have crimps so as to have an average number of crimps of 10 or more per inch under conditions that do not make the thermal fusion bond between the fibers clear; The crimped nonwoven fabric is shaped by compression, tension, etc. under conditions in which thermal fusion bonding between the fibers is not clear, or there is no thermal fusion bonding between the fibers, or there is no thermal fusion bonding between the fibers. This is a method for producing an extremely flexible nonwoven fabric in which the highly pseudo-substantial shape retention of the nonwoven fabric is due to the entanglement of fibers. The contents of the present invention will be explained in detail below. In the method for producing a long-fiber nonwoven fabric according to the present invention, a web made of latent crimpable composite continuous filaments made of a thermoplastic organic synthetic polymer is obtained by a spunbond method. That is, one component constituting the continuous filament is a thermoplastic organic synthetic polymer having fiber-forming ability, preferably polyethylene terephthalate,
Homopolymers such as nylon 6, nylon 66, and polypropylene are selected, but other homopolymers and copolymers may also be used. The other component is a thermoplastic organic synthetic polymer having a different heat shrinkage ability, and may be the above-mentioned homopolymer, preferably a copolymer of polyester, polyamide, or polyolefin that has a high heat shrinkage ability. Combinations and blends can be used. In a composite fiber made of at least two thermoplastic organic synthetic polymers having different heat shrinkability, the components must be arranged eccentrically in its cross section. In other words, in addition to an eccentric arrangement that is divided into two parts, such as a bonded type or an eccentric sheath-core type, eccentric arrangement that is divided into three or more parts is possible, and it is possible to have an eccentric arrangement that is divided into three or more parts. The eccentric sheath-core type is preferable when a combination of parts lacking in properties, when the spinnability of one component is extremely poor, or when the difference in melting point of the components used is large, and may be arbitrarily selected depending on the components and combination. In the present invention, it is necessary to have a large crimp force, and an eccentric arrangement such as a bonded type or an eccentric sheath-core type with a semicircular core is preferable. In order to obtain a latent crimpable composite continuous filament web, a spinning equipment having two or more extruders and a large number of nozzles is used, and the molten polymer is eccentrically arranged as described above to form a composite structure. The yarn is pulled by a high-speed air current and dispersed on a net conveyor or the like. As the spinning conditions at this time, the spinning conditions used in the normal spunbond method may be selected, but the spinning speed is 4000 m/
Minutes or more is preferable. That is, if the spinning speed is less than 4000 m/min, the strength of the resulting fibers will be insufficient, the elongation will be high, and the fibers will be in a so-called undrawn state, making it impossible to obtain practical physical properties. On the other hand, if the spinning speed is too high, the crimp shrinkage ratio defined in the present invention cannot be obtained with certain polymer combinations, and the spinning speed is set at 4,000 to 8,000 m/min. The single fiber properties of the composite fiber spun by high-speed traction in this manner are a strength of 2.0 g/d or more and an elongation of 100% or less, making it a composite continuous filament with latent thermal crimpability. The potential thermal crimpability of the composite fiber here is adjusted by the combination of components that make up the composite fiber, the thickness and cross-sectional shape of the fiber, the arrangement method and mass ratio of the components in the fiber cross-section, and the spinning conditions. It is possible to change the temperature depending on the following heat treatment conditions. In the present invention, these conditions should be selected such that the composite fiber has the potential crimp shrinkage rate shown in the present invention after heat treatment. That is, the method for producing a long fiber nonwoven fabric of the present invention includes a step of heat treating the latent crimp composite continuous filament web. The heat treatment conditions in the present invention include a crimp shrinkage rate of the composite fiber of 20% at a temperature 40°C lower than the melting point of the component with the lowest melting point among the composite fiber components.
or above, and by heat treatment, the fiber shrinkage rate at that temperature is at least 2% compared to that before heat treatment.
Conditions are selected that cause the decrease. The crimp shrinkage rate and fiber shrinkage rate referred to here are defined as the fiber length initially measured under a load of 0.5 g/d, and then subjected to a load of 1 mg/d to cause crimp and shrinkage in a heated atmosphere. Let the fiber length under that load be l ₁ , and 1
If the fiber length is l ₂ when a load of 0.5 mg/d is applied instead of the load of mg/d, the crimp shrinkage rate is l ₂ −l ₁ /l ₂ × 100, and the fiber shrinkage rate is l ₀ −l. ₂ / l ⁰ × 100, and in the present invention, in order to measure the crimp shrinkage rate and fiber shrinkage rate, the heating atmosphere temperature that causes crimp and shrinkage is set at the lowest temperature among the composite fiber components. The temperature was set to be 40°C lower than the melting point of the melting point component. That is, in the present invention, the composite fibers constituting the web have the latent crimp-generating ability to sufficiently develop crimp when crimp occurs, while heat treatment is applied to suppress shrinkage of the fiber itself due to heating. Ru. The composite fiber of the present invention is drawn at high speed and does not have a large fiber shrinkage rate even without heat treatment, but the heat treatment that reduces the fiber shrinkage rate by at least 2% promotes the crystallization of the fibers and self-generates. By reducing adhesion and suppressing unnecessary shrinkage of fibers when crimp occurs and fusion bonding between fibers, it is possible to produce a flexible and bulky nonwoven fabric. Furthermore, an unexpected effect of this heat treatment is that the nonwoven fabric that has undergone the heat treatment to develop crimp becomes uniform without unevenness. That is, non-uniform crimp shrinkage spots are prevented in the form shrinkage of the web due to crimp development, and the basis weight and mechanical properties of the nonwoven fabric are uniform without any spots, which is a very important effect. Although it is not clear why a uniform nonwoven fabric can be obtained by applying heat treatment in this way, it reduces the crimp appearance of the composite fibers that make up the web. It is presumed that the compression force is equalized. When carrying out this heat treatment, it is necessary to select appropriate conditions depending on the combination of components of the composite fiber, spinning conditions, web area weight, etc. That is, if the temperature is too low, the effect of heat treatment will not be seen, and the nonwoven fabric will be finished with many spots and poor flexibility when crimp occurs. In addition, if the temperature is too high, the ability of the composite fiber to develop crimp will decrease, resulting in not being able to obtain the crimp shrinkage rate necessary for the nonwoven fabric of the present invention, and generally lowering the glass transition point of the components constituting the composite fiber. The melting point is selected such that the heat-treated fiber satisfies the conditions shown in the present invention, with the melting point being above the highest glass transition point and below the lowest melting point. The present invention is characterized in that the latent ability to develop crimp, which is unique to composite fibers, is brought to light after needling. It is necessary to keep the shrinkage to a level where it is recognized, and the heat treatment method for this purpose is to pass the continuous filament web between heated rollers with an appropriate gap,
The web is not completely free, for example by placing it on a conveyor net and passing it through a heating area with a cover net.
It is preferable to perform the heat treatment with some restraint, so that the transition to the next step is carried out smoothly. That is, the method for producing a nonwoven fabric according to the present invention includes a step of needle punching the continuous filament web that has been heat treated in this way at a needle density of 5 to 100 P/cm ² on one side. At this time, if the needle density is less than 5P/ ^cm2 , the crimped nonwoven fabric will have disadvantages such as not having sufficient tensile strength, poor elongation recovery, and poor abrasion resistance. In addition, when the needle density exceeds 100P/cm ² , the degree of entanglement during needle punching increases, and sufficient crimp does not occur during the crimp treatment, resulting in uneven crimp development and noticeable needle marks, resulting in poor quality. It has been found that the fibers are damaged and the tensile strength is significantly reduced due to fiber breakage. Also, in order to increase the needle density, it is necessary to reduce the processing speed.
This is also a big problem in terms of productivity. Therefore, in carrying out the present invention, the needle density is 5 to 100P/cm ²
is selected. Further, in the present invention, needle punching from both sides is also effective in improving surface wear resistance and other physical properties. In this case, a needle density of 5 to 100 P/cm ² is possible for each surface, and a total needle density of 10 to 200 P/cm ² is possible.
A needle density of 150 P/cm ² gives favorable results. In the present invention, needle punching is performed on a continuous filament pulled at high speed, and since the elongation of the filament is small, the filament may break depending on the needling conditions, but at the needle density shown in the present invention, the elongation of the filament is small. The obtained nonwoven fabric consists essentially of long fibers and exhibits favorable physical properties peculiar to long fibers. In addition, in this needle punching, so-called crimp does not occur, and the composite fibers are merely mechanically entangled, and the composite fibers still have a potential crimp ability. In the present invention, this needle punch produces a penetrating intertwined fiber bundle of composite fibers. The penetrating intertwined fiber bundles herein refer to fiber bundles that are mechanically arranged in the thickness direction of the web by needles,
The meaning of "penetrating" includes cases in which the fibers hooked by the protrusion of the needle literally penetrate from the front side to the back side, and cases in which the fibers penetrate from the middle layer to the back side. Further, by needling, in addition to such penetrating entangled fiber bundles, penetrating entangled fiber bundles having an entangling effect are also produced, which may naturally occur in carrying out the present invention. This penetrating entangled fiber bundle can be easily produced by adjusting the needle depth during needling, and in the present invention, at least a part of the needle protrusion can reach the back side of the web. Depth is selected. The penetrating entangled fiber bundle thus obtained has a loop-like or napped-like form exposed on the web surface, which plays an important role in the production of the nonwoven fabric of the present invention. Conditions other than needle density and needle depth in needling may be arbitrarily adopted, and needle type (barb shape of felt needles, fork shape of fork needles), needle count, processing speed, etc. may be set as appropriate. selected.
Furthermore, in order to increase the effect of needling, means such as application of chemicals may be used in conjunction with the needling. Ordinary needle-punched nonwoven fabrics rely only on needle punching to maintain their shape, so the needle density is
While the needle density is generally 100 to 400 P/cm ² , in the present invention, preferable physical properties of the nonwoven fabric can be obtained with an extremely low needle density, and one of the features of the present invention is unprecedentedly high productivity. The method for producing a nonwoven fabric of the present invention includes a crimp development step in which the needle-punched latent crimpable composite long fiber web exhibits 10 or more crimps per inch. At this time, in order to obtain the nonwoven fabric referred to in the present invention, it is essential to select conditions that do not make the thermal bonding between the fibers clear. In the present invention, fibers that have been pulled at high speed are used, and the fibers are further crystallized by heat treatment, and the crimp onset temperature is the lowest melting point component that forms the surface layer of the cross section of the composite fiber. Temperatures below the melting point are employed. That is, in the method for producing a nonwoven fabric of the present invention, as long as the shape retention is substantially due to the entanglement between the fibers, a slight amount of pseudo heat-sealing bonding between the fibers is allowed, and the web can freely form crimps. The above temperature is adopted because it is necessary to shrink the fibers and there is almost no compressive force between the fibers. Therefore, in the case of a combination of a high melting point component and a low melting point component, such as a bonded type or an eccentric sheath-core structure in which the low melting point component serves as a sheath, processing should be performed at a temperature below the melting point of the low melting point component. Similarly, in the case of an eccentric sheath-core structure in which a high melting point component and a low melting point component are combined, and the low melting point component is the core, it is sufficient to process the temperature below the melting point of the high melting point component, but even if it is inside the fiber cross section, No, it is not recommended to process at a temperature above the melting point of the low melting point component, and when processing at a temperature above the melting point of the low melting point component, it is necessary to stop the process instantaneously. Furthermore, in the case of such a fiber cross-sectional structure, crimping can occur below the softening point of the high-melting point component forming the surface layer, and it is easy to produce a nonwoven fabric without thermal bonding between the fibers. will be achieved. A feature of the nonwoven fabric manufacturing method of the present invention is that the shape retention of the nonwoven fabric is achieved not by heat fusion bonding between the fibers, but by entangling the fibers. This will be clarified by comparing the nonwoven fabric of the present invention in which there is no bonding or the thermal bonding is extremely simulative, and the nonwoven fabric in which the thermal bonding is clearly defined. That is, in the present invention, thermal fusion bonding should be kept to a range where it does not exist or is extremely pseudo; clear thermal fusion bonding greatly impairs the flexibility of the nonwoven fabric and reduces the elongation recovery rate and tear strength. This is not desirable. In addition, the pseudo-thermal bonding between fibers as used in the present invention is only a slight amount of adhesion and is hardly involved in maintaining the shape of the nonwoven fabric. A nonwoven fabric that has been treated to a temperature above the softening point of the melting point component and below the melting point, and an eccentric sheath-core composite fiber that is a combination of the same components and has a low melting point component as its core, and has been processed to a temperature below the softening point of the high melting point component. This is recognized because the physical properties of the two do not change much. In this crimp development process, the composite fibers constituting the web have a number of crimp according to their potential crimp development ability.
10 or more crimps/inch become apparent. That is,
If the number of crimps is less than 10/inch, the crimps are not sufficiently developed and there is no fine entanglement between the fibers, resulting in poor tensile and tearing strength.
The resulting nonwoven fabric has poor flexibility, stretchability, and abrasion resistance, and lacks bulk and surface uniformity. In addition, in the present invention, if the number of crimps is 10 or more per inch,
Although there is no particular restriction, if the number of crimps is too large, the flexibility of the nonwoven fabric will not be significantly improved and it is not an economically advantageous method, so it is not preferable, and the number of crimps is 100// An inch or less is sufficient. That is, it is preferable to develop crimp so that the linear shrinkage rate (CS) of the web due to the occurrence of crimp is 5 to 30%, and CS is the basis weight of the nonwoven fabric before and after the occurrence of crimp, respectively _. ,G ₁ as (1−√
It is a numerical value expressed as G ₀ /G ₁ )×100. In addition, due to this crimping, the intertwined fiber bundles of the composite fibers produced in the previous needle punching process are penetrated into a loop shape or penetrated and cut into a nape shape, and at the part exposed to the surface layer, other Since there is no restriction due to intertwining between the fibers as in the locations shown in FIG. In this coiled crimping, the number of crimps is greater than the average number of crimps of the composite fibers constituting the nonwoven fabric, which is 1.2 times or more.
Because it forms a fine pill shape and has a three-dimensional volume, threads do not easily come off and provide many desirable physical properties to the nonwoven fabric. As a result of this crimping, the web that has already been needle punched shrinks in the plane direction and increases in the thickness direction, so any method or device suitable for this may be used. That is, methods such as contacting with a hot roll or passing through a heating area such as an oven to freely develop crimp, or special heating methods such as far infrared or high frequency may be used. Furthermore, as long as the present invention is followed, the shrinkage of the fibers themselves in the web due to heating is extremely small, so the number of crimps of the composite fibers correlates with CS, and it is also possible to adopt a method of regulating CS in order to control the physical properties of the nonwoven fabric. . In other words, it is possible to control shrinkage in the width direction using a pin tenter or clip tenter, it is possible to control shrinkage in the machine direction by providing an overfeed mechanism, or an appropriate An appropriate method may be adopted, such as controlling the thickness by passing it between heated rolls having gaps. Furthermore, by applying these regulating methods, it is easy to manufacture nonwoven fabrics that are extremely stretchable in only one direction, and are naturally included in the present invention. The present invention includes further shaping the crimped nonwoven fabric to the extent that thermal fusion bonding does not become clear, and it is possible to shape the surface and modify the physical properties by compression or tension. In this process as well, it is necessary not to make heat fusion bonding obvious.
For this purpose, for example, the width can be increased using a tenter, etc.
When almost no pressure is applied to the fibers, such as by heat setting or by softening the surface of the nonwoven fabric using a hot plate or hot roll to make it smooth, the temperature conditions are below the melting point of the components forming the surface layer of the cross section of the fibers. However, if a pattern is applied using an engraving plate or an engraving roll, or the density is greatly changed by strongly compressing it with a hot plate or a hot roll, it is natural that the components that form the surface layer of the fiber cross section are used. should be processed at temperatures even lower than the melting point of From this point of view, it is possible to adopt a wide range of temperature and pressure conditions for composite fibers made of a combination of high melting point and low melting point components by using an eccentric sheath-core type with a low melting point component as the core. preferable. The effect of shaping this crimped nonwoven fabric is to change the density and thickness of the nonwoven fabric to produce a nonwoven fabric with desired physical properties depending on the application, and to further increase the uniformity of the surface. That is, the nonwoven fabric of the present invention includes penetrating intertwined fiber bundles of composite fibers, which exhibit fine fluff-like shapes at the locations where they penetrate and are exposed to the surface layer, and these are pressed against the surface of the nonwoven fabric to make them inconspicuous. Alternatively, it is possible to further improve the quality of the nonwoven fabric by making needle marks, which have become almost invisible due to crimp development, even less noticeable, and by further increasing surface uniformity. The method for manufacturing the long fiber nonwoven fabric of the present invention consists of a series of steps as described above, and includes a spunbond method in which continuous filaments melted and discharged from a number of nozzles are drawn and thinned by high-speed air currents and deposited to form a web. It is preferable to apply. However, other methods are possible as long as continuous filaments are used in accordance with the present invention, including spunbond methods using high speed rotating rolls. Furthermore, in the production method of the present invention, it is of course possible to mix other fibers with the latent crimpable composite fibers, thereby adjusting the physical properties of the resulting nonwoven fabric and suppressing shrinkage spots when crimp occurs. 50wt% of latent crimpable long fibers as used in the present invention.
It is effective when it contains more than The long-fiber nonwoven fabric of the present invention is made of eccentric composite fibers of a thermoplastic organic synthetic polymer exhibiting thermal crimpability, and includes long fibers with visible crimp. Has 10 or more crimps/inch,
(b) The conjugate fibers form intertwined fiber bundles that penetrate in the thickness direction of the nonwoven fabric; (c) The conjugate fibers, which are penetrating intertwined fiber bundles, form a more highly coiled shape at the part where the conjugate fibers penetrate and are exposed to the surface layer. It has crimps and is in the form of a pill or a pill pressed against the surface of the nonwoven fabric.
It is a long fiber nonwoven fabric that maintains its shape by being three-dimensionally intertwined, and is characterized by sterically hindering yarn shedding. That is, macroscopically, the intertwined fiber bundles penetrating the nonwoven fabric in the thickness direction largely maintain the shape of the entire nonwoven fabric, and microscopically, the composite long fibers that make up the nonwoven fabric are intertwined by fine three-dimensional crimp. In addition, the composite fibers that become the penetrating entangled fiber bundles become more highly coiled and crimped in the part where they pass through and are exposed to the surface layer, so the intertwined fibers do not come out easily. It is a completely new long fiber nonwoven fabric that has an unbreakable structure and maintains the form of a nonwoven fabric when these are integrated. One of the characteristics of this long-fiber nonwoven fabric is that the composite fibers constituting the nonwoven fabric have an average number of crimps of 10 or more per inch, which is unique to the eccentric heat-crimpable composite fiber structure. This crimp became apparent after at least some of the fibers were entangled with the needle punch, resulting in complex entanglements,
It has an effect on the tensile strength, elongation and elongation recovery of the physical properties of the nonwoven fabric, resulting in a nonwoven fabric with a sense of volume and a beautiful appearance on the surface. Further, this long-fiber nonwoven fabric has intertwined fiber bundles that penetrate in the thickness direction of the nonwoven fabric containing composite fibers, and these are fiber bundles produced by needle punching. In other words, it is a fiber bundle that is forcibly arranged and penetrated by the protrusion of the needle, and the size of the bundle and the number of fibers in the bundle can be arbitrarily determined depending on the protrusion of the needle and the diameter of the fibers. It is selected. Further, the number of bundles is selected depending on the needle density of needle punching. Furthermore, the composite fibers that have become a penetrating intertwined fiber bundle manifest a more advanced coil-like crimp in the part that penetrates and is exposed to the surface layer, resulting in fine pill-like formations.
Alternatively, this pill is compressed on the surface of the nonwoven fabric, and the threads do not easily come off.
Contributes to the tensile properties and tear strength of nonwoven fabrics, and imparts wear resistance and uniformity to the surface. That is, the long-fiber nonwoven fabric of the present invention is made by needle punching to form latent crimpable conjugate fibers 1 as shown in FIGS. 1 and 2.
After forming the loops 2 and napped 3, crimps are developed, and the loops 2 and napped 3 are highly crimped on the surface of the nonwoven fabric made of crimped composite fibers 4 as shown in FIGS. 3 and 4. It has a structure with a fluff 5 and a fluff 6. Furthermore, this hairball 5 and hairball 6
Alternatively, it has a structure 7 that has been compressed and pressed as shown in FIG. Therefore, the nonwoven fabric of the present invention is a long fiber nonwoven fabric having a unique structure composed of eccentric composite long fibers, and because of this structure, it has excellent physical properties that have never existed before. In other words, it is a long-fiber nonwoven fabric that has great tensile strength at break and excellent elongation recovery, exhibits high tear strength and abrasion resistance, is extremely flexible, has a bulky and voluminous feel, and has a uniform surface and a luxurious appearance. It is. The long-fiber nonwoven fabric of the present invention is made of eccentric composite fibers of a thermoplastic organic synthetic polymer exhibiting thermal crimpability, and long fibers with visible crimp.The composite fibers have different thermal shrinkability. Consists of two or more components. One of these components may be selected from polyester, polyamide, polyolefin, etc. that have fiber-forming ability, and the other component may be selected from a component that has a different heat shrinkage ability. From the viewpoint of interfacial affinity and heat crimping ability in composite fibers, preferably,
Preferred are a combination of polyester and its copolymer, a polyamide and its copolymer, a polypropylene and polyolefin copolymer, and the like. More preferably, it is a combination of polyester and its copolymer, and the nonwoven fabric of the present invention overcomes the "hardness" and "paper-likeness" that were the biggest drawbacks of conventional polyester nonwoven fabrics, and is an extremely flexible nonwoven fabric. It is. As the polyester, polyethylene terephthalate may be selected, as its copolymer, various copolymers of polyethylene terephthalate may be selected, and as the copolymerization component, as the acid component, various types such as isophthalic acid, phthalic acid, glutaric acid, adipic acid, etc. may be selected. An acid is possible, and various glycols such as diethylene glycol, propylene glycol, 1,4-butanediol, and 2,2-bis(4-hydroxyethoxyphenyl)propane can be used as the glycol component. Moreover, the cross-sectional structure of the composite fiber shown in the present invention may be any known composite cross-sectional structure as long as two or more components are eccentrically arranged. for example,
This composite fiber is a combination of relatively high melting point and low melting point, and has a cross-sectional structure in which the low melting point component is the core and the high melting point component is the sheath. The nonwoven fabric made below is
It does not have heat-sealed bonding and retains its shape only by entanglement between fibers, and is a typical nonwoven fabric of the present invention. In addition, although the components are the same combination of high melting point and low melting point, and the low melting point component forms at least a part of the outer layer surface in the cross section of the fiber, it has an eccentric structure, but an appropriate one with a melting point below the low melting point component is used. Nonwoven fabrics that have been crimped or shaped as desired will either have no thermal bonding between the fibers, or the thermal bonding will be extremely artificial, and the shape of the nonwoven fabric will not be maintained effectively due to the formation of nonwoven fabrics. This is naturally included in the present invention. Furthermore, the shape retention of the nonwoven fabric according to the present invention is substantially due to the entanglement between the fibers, and the fact that thermal fusion bonding does not exist or is extremely pseudo means that, for example, when the nonwoven fabric of the present invention has a width of 0.1 to 1.0 mm, When cut into slits or small pieces, the slits or pieces can be easily separated into individual filaments with fingertips or needle-like objects, which is different from ordinary heat-sealed nonwoven fabrics. Further, the manufacturing method of the nonwoven fabric according to the present invention is not limited to the above-mentioned spunbond method. That is, a web made of composite continuous filaments that exhibit latent thermal crimpability and have physical properties equivalent to drawn yarns is needled to produce penetrating intertwined fiber bundles without shrinking, and then the composite fibers are crimped. Naturally, non-woven fabrics made by opening composite fiber tows are also included. The fineness of the fibers constituting the long-fiber nonwoven fabric of the present invention is not particularly limited, but if the fineness is too small, the fibers will break easily when needle punched, although they will be flexible, making it difficult to obtain the tensile strength of the nonwoven fabric. In addition, if the fineness is too large, the crimp loops will be large and the number of crimp will tend to be small, making it impossible to obtain a desirable intertwined state, and the surface will lack smoothness and luxury. 1 to 10d is preferable. Further, the fiber cross-sectional shape may be circular, oval, or any other conventionally known shape. Further, the basis weight of this long fiber nonwoven fabric is not particularly limited, but it is preferably 50 to 500 g/m ² and should be arbitrarily set depending on the use. Due to its unique structure, the long fiber nonwoven fabric of the present invention has a variety of very distinctive properties.
That is, it has excellent mechanical properties, is bulky and flexible, and has a high-quality surface.
For example, the long fiber nonwoven fabric of the present invention made of polyethylene terephthalate and its copolymer usually has the following physical properties. Tensile strength at break is 3 to 6g/tex, tensile strength (fabric weight: 100g/ ^m2 conversion) 4Kg or more, 15% elongation recovery rate
60% or more, compression rate of 20% or more, compression recovery rate of 80% or more, high strength, excellent recovery properties, and pure bending rigidity of 1.0g・cm ² /cm or less even at a basis weight of 200g/m ² It is a bulky nonwoven fabric that is extremely flexible and can have a density in the range of 0.05 to 0.3 g/cm ³ . The long fiber nonwoven fabric of the present invention having various excellent characteristics as described above can be used for various purposes. For example, synthetic leather and artificial leather base fabrics, base fabrics for medically-use affected area covering materials, interior surface materials and interlinings such as curtains, tablecloths, wall coverings and automobile ceiling materials, and even filters that take advantage of their special structure. It has many uses. Of course, it can also be used in the form of lamination with films, woven fabrics, knitted fabrics, and other non-woven fabrics.
Taking advantage of the bulkiness of the nonwoven fabric of the present invention, it is easy to impregnate it with resin and make it into various products. Regarding the various physical properties of the nonwoven fabric used in the present invention and their measurement methods, the tensile strength and elongation are values measured using a tensile tester at a grasp length of 10 cm, a sample width of 3 cm, and a tensile speed of 30%/min. Breaking strength is expressed in g/tex,
It is calculated as breaking strength [Kg]/3 [cm] x basis weight [g/m ² ] x 100. In addition, the elongation recovery rate is a value based on a constant elongation of 15% in accordance with JISL-1079. Compression rate and compression recovery rate are 10 cm x 10 from non-woven fabric.
Sample 10 square pieces of cm, and these 10
Stack the sheets and place a thin metal plate of the same width on top of it (50
g) was placed, left for 2 minutes, its thickness t ₀ was measured, and then a load of 10 kg was applied evenly over the entire surface and left for 30 minutes. The thickness t ₁ after 30 minutes under load is measured, then the load is removed and the thickness t ₂ is determined after being left for another 30 minutes. From t ₀ , t ₁ , and t ₂ , the compression rate and compression recovery rate are: Compression rate = t ₀ − _{t 1} / t ₀ × 100 (%) Compression recovery rate = t ₂ − t ₁ / t ₀ × 100 (%) is given by In addition, pure bending rigidity, which is a measure of flexibility, can be measured using a pure bending rigidity meter (KES-F2 type) made by Kato Seisakusho.
Measured at The tear strength is a value measured using an Elmendorf tear tester. The number of crimp in the nonwoven fabric is determined by observing it with a magnifying glass with a scale of minimum unit 100μ, measuring the distance (mm) between the peaks and valleys of the crimp, and finding the average value (n = 15). The number of crimps in between is calculated as [25.4/average distance]. In addition, although the fibers constituting the nonwoven fabric in the present invention are arranged randomly, the physical properties of the nonwoven fabric shown in the present invention are measured in the machine direction and cross-machine direction in order to reduce the influence of fiber arrangement. The average value is used. EXAMPLES The present invention will be explained below with reference to Examples, but the Examples are not intended to limit the present invention in any way. Example 1 Intrinsic viscosity 0.65 (in 0-chlorophenol, 35°C)
Contains polyethylene terephthalate (melting point 261℃) and 10 mol% isophthalic acid, melting point intrinsic viscosity 0.62
Using polyethylene terephthalate copolymer at 231℃, the molten polymer was discharged in a laminated arrangement with a discharge rate ratio of 1:1, pulled at high speed with an air sucker, opened, dispersed, and aggregated to form a continuous filament web. . This composite fiber has a single yarn of 3.6d (in terms of yarn speed)
At 5200 m/min, the strength was 2.9 g/d, the elongation was 65%, and the fiber shrinkage was 9%. This web was heated to 160℃ with a gap of 500μ.
The mixture was passed through a pair of calender rolls for heat treatment. The composite fibers constituting the heat-treated web are continuous filaments with a fiber shrinkage rate of 4% and a latent crimpability with a crimp shrinkage rate of 35%, with almost no apparent crimp. This web is made using a 36th felt needle.
A kneepan web containing penetrating interlaced fibers with a basis weight of 120 g/m ² was obtained by needle punching at a needle density of 30 P/cm ² and a needle depth of 9 mm. This was treated with a pin tenter heated to 220°C for 30 seconds in the machine direction and cross-machine direction at an overfeed rate of 15% to develop crimp. The obtained nonwoven fabric has a basis weight of 155 g/m ² (CS=
12%), there are 45 crimps per inch, and the pure bending stiffness is 0.51g・cm ² /cm, making it extremely flexible.
It has a high recovery rate during elongation of 79%, exhibits extremely excellent elasticity, has a bulky density of 0.15 g/ ^cm2 , has a tensile strength at break of 4.8 g/tex, and has a tensile elongation at break of 85%, with almost no needle punch marks. It was a nonwoven fabric with a uniform surface that could not be distinguished. In addition, pill-like fibers with highly crimped coil-like crimps were confirmed on the surface of the nonwoven fabric using a magnifying glass. This state is easy to understand when observing the cross section of the nonwoven fabric, and the structure schematically shown in FIGS. 3 and 4 is confirmed by observing with a magnifying glass. Comparative Example 1 When the continuous filament web obtained in Example 1 was subjected to the same needle punching and crimp development treatment without heat treatment, the fabric weight was 157 g/m ² (CS=
13%) was obtained, but due to the high fiber shrinkage rate, crimp development did not occur sufficiently, and the crimp was 8.
As few as pieces/inch, pure bending rigidity is 1.35g.
The nonwoven fabric had a high flexibility of cm ² /cm.
In addition, the nonwoven fabric had very noticeable unevenness. Example 2 Intrinsic viscosity 0.65 (in 0-chlorophenol, 35°C)
of polyethylene terephthalate (melting point 261℃),
As the diol component, a polyethylene terephthalate copolymer with an intrinsic viscosity of 0.63 and a melting point of 236°C containing 10 mol% of 2,2-bis(4-hydroxyethoxyphenyl)propane was used, and the discharge rate ratio (PET/
The molten polymer is discharged in an eccentric sheath-core arrangement in which the copolymer component of COPET) 2/1 forms a semicircular core.
The filaments were pulled at high speed using an air satsuka car, and the fibers were opened, dispersed, and accumulated to form a continuous filament web. This composite fiber has a strength of 3.1 with a single yarn of 4.0 d (fiber speed converted to 4700 m/min).
g/d, elongation was 74%, and fiber shrinkage was 12%. The gap between the rolls that heated this web to 155℃
It was heat-treated by passing it through a pair of 500μ calender rolls. By heat treatment, the fiber shrinkage rate of the composite fiber was reduced to 6%, resulting in a latent crimpable continuous filament with a crimp shrinkage rate of 31% and almost no apparent crimp. This heat-treated web was needle-punched using a No. 40 felt needle at a needle density of 50P/cm ² and a needle depth of 10 mm to obtain a kneepan web having a basis weight of 80 g/m ² . This was heated to 215℃ between hot plates with a gap of 1cm.
After leaving it for 10 seconds, compression shaping was performed for 5 seconds with the distance between the hot plates set to 1.2 mm. The obtained nonwoven fabric has a basis weight of 115 g/m ² (CS = 17%), a number of crimps of 51/inch, a pure bending stiffness of 0.24 g cm ² /cm, a recovery rate of 85% at 15% elongation, and a tensile It had a breaking strength of 5.4 g/tex, a tensile elongation at break of 90%, and a density of 0.09 g/cm ³ , making it an extremely flexible and bulky nonwoven fabric with a uniform surface. Further, by observing the cross section of the nonwoven fabric with a magnifying glass, a structure as schematically shown in FIG. 5 was confirmed. Comparative Example 2 A continuous filament web with a basis weight of 80 g/m ² was manufactured by changing the PET/COPET discharge ratio of Example 2 to 4/1. This composite fiber has a single yarn of 3.8 d (yarn speed equivalent: 4900 m/
min), strength 3.3g/d, elongation 68%, fiber shrinkage rate 9
It was %. This web was heat treated, needle punched, crimped, and compressed in the same manner as in Example 2, and the obtained nonwoven fabric had a basis weight of 88 g/m ² (CS = 5%).
The number of crimps is 5/inch and the pure bending rigidity is 0.68g.
The recovery rate at cm ² /cm and 15% elongation was 42%, indicating that the nonwoven fabric lacked flexibility and stretchability. The crimp shrinkage rate of the composite fiber after heat treatment at this time was 12. Comparative Example 3 The fabric weight was 80 in the same manner as in Example 2 except that the eccentric sheath-core arrangement in Example 2 was changed to a bonded arrangement.
A continuous filament web of g/m ² was produced. This composite fiber had a single yarn of 4.1 d (fiber speed converted to 4700 m/min), strength of 3.0 g/d, elongation of 72%, and fiber shrinkage of 10%. This web was heat treated, needle punched, crimped, and compressed in the same manner as in Example 2. The obtained nonwoven fabric had a basis weight of 125 g/m ² (CS = 20%), a number of crimps of 61/inch, and a pure Bending rigidity is 0.36g・
^cm2 /cm, recovery rate at 15% elongation is 87%, tensile strength at break is 5.2g/tex, tensile elongation at break is 97%, tear strength is 6.4Kg or more, density is 0.11g/ ^cm3 , and it is extremely flexible. It was a bulky nonwoven fabric with a uniform surface. This nonwoven fabric
The nonwoven fabric obtained by compression shaping for 5 seconds between hot plates heated to 240°C with a gap of 1.0 mm has a pure bending rigidity of 2.3.
g·cm ² /cm, which is extremely high, and the recovery rate at 15% elongation also drops to 37%. Furthermore, the tear strength significantly decreases to 1.2 kg. This nonwoven fabric was cut into slit pieces with a width of 0.5 mm, placed on a board, and even when rubbed with the fingertips, the fabric did not separate into single fibers, and the heat-sealed bond between the fibers was strong. This was also confirmed by magnifying glass observation. Example 3 Intrinsic viscosity 0.65 (in 0-chlorophenol, 35°C)
of polyethylene terephthalate (melting point 261°C) and nylon 6 with a relative viscosity of 2.4 (in 95% sulfuric acid, 30°C).
(melting point 215℃) using nylon 6 with a discharge rate ratio of 1/1.
The molten polymer is discharged in an eccentric sheath-core arrangement with a semicircular core, and is towed at high speed with an air suction car.
The fibers were spread, dispersed, and accumulated to form a continuous filament web. This composite fiber has a single yarn of 1.8d (yarn speed conversion: 5200
The strength was 3.3 g/d (m/min), the elongation was 78%, and the fiber shrinkage was 13%. This web was heat-treated by passing it through a pair of calender rolls heated to 160°C. By heat treatment, the fiber shrinkage of the composite fiber was reduced to 8%, resulting in a latent crimpable continuous filament with a crimp shrinkage of 25%. This heat-treated web was needle-punched using a No. 40 felt needle at a needle density of 30P/cm ² and a needle depth of 10 mm to obtain a kneepan web having a basis weight of 100 g/m ² . After leaving this for 10 seconds between hot plates heated to 200℃ with a gap of 1 cm, the distance between the hot plates was increased to 1.2
Compression shaping was performed for 5 seconds as mm. The obtained nonwoven fabric had a basis weight of 153 g/m ² (CS = 19%) and a crimp count of 43.
pieces/inch, pure bending rigidity 0.54g・cm ² /cm, 15
Recovery rate at % elongation is 78%, tensile strength at break is 5.9
g/tex, tensile elongation at break 82%, density 0.12 g/cm ³
It was an extremely flexible, bulky nonwoven fabric with a uniform surface. The cross-sectional structure of this nonwoven fabric was confirmed to be as schematically shown in FIG. 5 by observation with a magnifying glass. In the case of a conjugate fiber in which polyethylene terephthalate and nylon 6 are bonded together in cross-section, the contact surface between the polyethylene terephthalate and nylon 6 is separated by needle punching, which impairs latent crimpability, which is not preferable. This crimpability decreases as the needle density of needle punching increases. Example 4 Nylon 66 with relative viscosity 2.7 (in 95% sulfuric acid, 30°C)
(melting point 261℃) and relative viscosity 2.3 (in 95% sulfuric acid, 30℃)
Using random copolyamide of 66/6T/6・10 = 35/15/50 (wt%), the random copolymer polyamide (melting point 218℃) has a semicircular shape at a discharge rate ratio of 1/1. Dispense molten polymer with mold arrangement,
The fibers were pulled at high speed by an air suction car, opened, dispersed, and accumulated to form a continuous filament web. This composite fiber has a strength of 2.1d (fiber speed equivalent: 5200m/min).
It had an elongation of 2.7 g/d, an elongation of 73%, and a crimp shrinkage rate of 14%. This web was heat-treated by passing it through a pair of calender rolls heated to 140°C. The composite fibers constituting the heat-treated web have a fiber shrinkage rate of 9% and a crimp shrinkage rate of 37%, which is a continuous filament having latent crimpability with almost no apparent crimp. This web is sewn using a 40-grit felt needle.
A kneepan web with a fabric weight of 100 g/m ² was obtained by needle punching with a needle density of 30 P/cm ² and a needle depth of 10 mm.
This kneepan web was treated with a pin tenter heated to 180°C for 30 seconds in the machine direction and cross-machine direction at overfeed rates of 15% and 30% to develop crimp, and then heated to 185°C with a 1 mm gap between the rolls. It was passed through a pair of calendar rolls and compressed. The physical properties of the obtained nonwoven fabric are shown in Table 1. The nonwoven fabric is extremely flexible and highly elastic, and has a uniform surface. Further, it was confirmed by observation with a magnifying glass that the cross-sectional structure of this nonwoven fabric was as schematically shown in FIG.

[Table] Example 5 Intrinsic viscosity 0.650 - in chlorophenol, 35°C)
polyethylene terephthalate (melting point 261℃) and polypropylene (melting point 170℃) (manufactured by Chitsuso Corporation:
S5056) was used to discharge the molten polymer in an eccentric sheath-core configuration in which the polypropylene was semicircular at a discharge rate ratio of 1/1, and was pulled at high speed by an air sucker to open and disperse the polymer to form a continuous filament web. This composite fiber has strength at 1d single yarn (4500m/min yarn speed conversion).
It had an elongation of 2.5 g/d, an elongation of 87%, and a fiber shrinkage rate of 12%.
This web was heat-treated by passing it through a pair of calender rolls heated to 120°C. The composite fibers constituting the heat-treated web have a fiber shrinkage rate of 9% and a crimping shrinkage rate of 24%, which is a latent crimpable continuous filament with some crimps becoming apparent. This web is needle-punched with a 40-count felt needle at a needle density of 30P/cm ² and a needle depth of 10mm.
The kneepan web was 120 g/m ² . This kneepan web was heated to 150℃ between hot plates with a gap of 1cm.
After leaving it for 10 seconds, compression shaping was performed for 5 seconds with the distance between the hot plates set to 1.2 mm. The obtained nonwoven fabric is
Fabric weight: 155 g/m ² (CS = 12%), number of crimps: 28/inch, pure bending rigidity: 0.64 g/cm ² /cm, recovery rate at 15% elongation: 68%, density: 0.12 g/cm ³ It was an extremely flexible, bulky nonwoven fabric with a uniform surface. It was confirmed by observation with a magnifying glass that the cross-sectional structure of this nonwoven fabric was as schematically shown in FIG.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams schematically showing the cross-sectional structure of a nonwoven fabric before crimping treatment in the process of manufacturing the long fiber nonwoven fabric of the present invention, and FIGS. 3, 4, and 5. 1 is a diagram schematically showing the cross-sectional structure of a long fiber nonwoven fabric of the present invention that has been subjected to crimp development treatment. 1... Latent heat-crimpable composite fiber, 2... Loop,
3... Napped, 4... crimped composite fiber, 5... pill,
6...Furball, 7...Furball pressed.

Claims (1)

[Scope of Claims] 1. A nonwoven fabric consisting of long fibers made of eccentric composite fibers of a thermoplastic organic synthetic polymer exhibiting thermal crimpability and with visible crimp, comprising: (a) the composite fibers having an average (b) The composite fiber has a number of crimps of 10 or more per inch, (b) The composite fiber is an interlaced fiber bundle that penetrates through the thickness direction of the nonwoven fabric, and (c) The composite fiber is a penetrating entangled fiber bundle. , The part penetrated and exposed to the surface layer has a higher degree of coil-like crimp, and the pill is in the form of a pill or the pill is pressed against the surface of the nonwoven fabric, and has a steric hindrance to thread removal. A long fiber nonwoven fabric whose shape is maintained by three-dimensional entanglement. 2. Claim 1 in which there is no thermal fusion bonding between the fibers or there is a pseudo thermal fusion bond between the fibers, and the shape retention of the nonwoven fabric is substantially due to the entanglement between the fibers.
Long fiber nonwoven fabric as described in Section 1. 3. The composite fiber has an eccentric sheath-core structure in which a low melting point component serves as a core and a high melting point component serves as a sheath in the cross section of the fiber, and there is no thermal fusion bonding between the fibers. The long fiber nonwoven fabric according to item 1. 4. A patent in which the composite fibers constituting the long-fiber nonwoven fabric consist of a combination in which one component is a substantially homopolymer of polyester, polyamide, or polyolefin, and the other component is a copolymer polyester, copolyamide, or copolymer polyolefin. The long fiber nonwoven fabric according to claim 1. 5. The long fiber nonwoven fabric according to claim 1, wherein the composite fibers constituting the long fiber nonwoven fabric are composed of a combination in which one component is polyethylene terephthalate and the other component is a copolymerized polyester containing ethylene terephthalate units. . 6 In the production of long-fiber nonwoven fabrics, (a) at least one component is a thermoplastic organic synthetic polymer capable of forming fibers, and the other components are thermoplastic organic synthetic polymers having different thermal shrinkage ability from the polymer; At least two combined components are melted, discharged so that they are arranged eccentrically in the cross section of the fiber, and pulled at a spinning speed of 4000 to 8000 m/min to form a potentially heat-crimpable composite fiber. (b) The crimp shrinkage rate of the composite fiber at a temperature 40°C lower than the melting point of the component with the lowest melting point among the composite fiber components is 20% or more. While maintaining
(c) applying a heat treatment to the continuous filament web to reduce fiber shrinkage by at least 2% at the temperature; (c) penetrating the heat treated continuous filament web with a needle density of 5 to 100 P/cm ² per side (d) The needle punched web is subjected to needle punching from only one side or both sides at a needle depth that can cause intertwined fiber bundles, and (d) an average of 10 fibers/fiber bundles are formed in the needle punched web under conditions that do not clearly form thermal fusion bonds between fibers.
1. A method for producing an extremely flexible long-fiber nonwoven fabric, comprising: making the composite fibers manifest crimps so as to have a number of crimps of an inch or more. 7 In paragraph (d) of claim 6, the crimp manifestation treatment that does not clarify the thermal fusion bonding between the fibers is defined as the melting point of the lowest melting point component forming the surface layer of the cross section of the composite fiber. A method for producing long-fiber nonwoven fabrics at a temperature lower than . 8 In claim 6, paragraph (a) is a composite fiber with an eccentric sheath-core structure in which the low melting point component serves as the core and the high melting point component serves as the sheath, and the crimp manifestation treatment in paragraph (d) is applied. A method for producing a long fiber nonwoven fabric in which there is no interfiber thermal fusion bonding performed at a temperature below the softening point of a high melting point component. 9 In the production of long-fiber nonwoven fabrics, (a) at least one component is a thermoplastic organic synthetic polymer capable of forming fibers, and the other component is a thermoplastic organic synthetic polymer having a different thermal shrinkage ability from the polymer; At least two combined components are melted, discharged so that they are arranged eccentrically in the cross section of the fiber, and pulled at a spinning speed of 4000 to 8000 m/min to form a potentially heat-crimpable composite fiber. (b) The crimp shrinkage rate of the composite fiber is 20% or more at a temperature 40°C lower than the melting point of the component with the lowest melting point among the components of the composite fiber. (c) applying a heat treatment to the heat-treated continuous filament web to reduce the fiber shrinkage rate by at least 2% at the temperature while maintaining the same ^temperature ; (d) needle-punching the needle-punched web from only one side or from both sides at a needle depth capable of producing penetrating entangled fiber bundles; Average 10 pieces/
(e) The nonwoven fabric under the visible crimps is shaped by compression or tension under conditions that do not make the thermal bonding between the fibers clear. A method for producing an extremely flexible long-fiber nonwoven fabric, characterized by: 10 In claim 9, paragraph (d) and
A method for producing a long-fiber nonwoven fabric in which the treatment described in item (e) that does not result in clear thermal fusion bonding between fibers is carried out at a temperature lower than the melting point of the component with the lowest melting point forming the surface layer of the cross section of the composite fiber. 11 In claim 9, paragraph (a) is a conjugate fiber with an eccentric sheath-core structure in which the low melting point component serves as the core and the high melting point component serves as the sheath, and the treatments in paragraphs (d) and (e) are applied. A method for producing long fiber nonwoven fabrics at a temperature below the softening point of the high melting point component.