JP6110089B2 - Nonwoven fabric and cushion material using the same - Google Patents

Description

  The present invention includes a nonwoven fabric that includes at least two types of three-dimensional crimped fibers, has excellent elasticity, softness, and bulk recoverability, and has a tactile sensation superior to that of a conventional nonwoven fabric, and a cushion material using the nonwoven fabric About.

  Conventionally, urethane foam has been widely used as a cushioning material for various seats including automobile seats, bedding items such as mattresses and bed mats, and clothing pads such as brassiere pads and shoulder pads. . However, from the viewpoint of safety, impact on the environment at the time of disposal, and lack of air permeability, the use of a nonwoven fabric containing crimped conjugate fibers as a cushioning material in place of urethane foam has been studied.

  For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 6-184898) discloses a fiber structure in which an inelastic crimped short fiber (A) and a coil spring-like fiber (B) are mixed, and has excellent cushioning properties. Cushioning materials that are satisfactorily, have excellent heat resistance, and are comfortable to sit on while sitting are being studied. In Patent Document 1, the coil spring-like fiber (B) has a coil spring-like crimp formed by the manifestation of the latent crimping ability (that is, a so-called latent crimped fiber). The spring-like fiber (B) is a composite fiber composed of a thermoplastic elastomer having a melting point lower by 40 ° C. or more than the melting point of the polymer forming the non-elastic crimped short fiber (A) and the non-elastic polymer. The thermoplastic elastomer B) is entangled with the fiber (A) at the intersection with the fiber (A), and the contact portion is heat-sealed.

  Patent Document 2 (Japanese Patent Laid-Open No. 6-304348) also discloses a fiber structure obtained by three-dimensionally mixing a non-elastic crimped short fiber (A) and a three-dimensional crimp-expressing elastic composite fiber (B), Cushioning materials that are excellent in cushioning properties, sagability, excellent heat resistance, and comfortable to sit on while sitting are being studied. In Patent Document 2, the three-dimensional crimp-expressing elastic composite fiber (B) has a three-dimensional crimp formed by revealing latent crimp ability (that is, a so-called latent crimp fiber). The elastic conjugate fiber (B) is composed of a thermoplastic elastomer (C) having a melting point 40 ° C. or more lower than the melting point of the polymer forming the inelastic crimped short fiber (A), and a melting point 30 ° C. or more higher than the thermoplastic elastomer (C). A composite fiber made of a thermoplastic elastomer (D) having the following properties: the thermoplastic elastomer (C) of this fiber (B) is entangled with the fiber (A) at the intersection with the fiber (A), and most of the bonded portion Is heat-sealed.

  Patent Document 3 (Japanese Patent Application Laid-Open No. 6-327856) discloses a futon stuffing material in which natural fibers and two or more types of polyester fibers are mixed, and at least one type of the above polyester fibers is disclosed. 3 denier or more and 15 denier or less latent crimped fiber and / or highly shrinkable fiber and manifested three-dimensional crimped hollow fiber, and the crimped fiber is subjected to heat treatment after blending. The latent crimped fiber and / or the highly shrinkable fiber in which crimps are expressed in this way is characterized by being intertwined with other fibers.

  Further, Patent Document 4 (Japanese Patent Laid-Open No. 2000-355864) discloses that a first web formed by mixing an actual crimped fiber filament, a latent crimped fiber filament, and a binder fiber filament is formed into a predetermined shape by needle punching and heat treatment. A vehicular seat wading material that satisfies the required vehicle seat characteristics such as bulkiness, sag resistance, form stability, elastic recovery, cushioning properties, and flexibility is disclosed. The present invention is characterized in that the binder fiber filaments are melted and bound together by heat treatment, and the latent crimped fiber filaments are crimped to bind these fiber filaments.

  Patent Document 5 (Japanese Patent Application Laid-Open No. 2008-274473) discloses a second component which is a polyester containing a linear low density polyethylene polymerized using a metallocene catalyst and a polyester containing 50% by mass or more of polytrimethylene terephthalate. Disclosed is a crimped bicomponent fiber containing components. Such an aggregate of fibers (for example, non-woven fabric) has a small volume reduction (sagging) at the time of heat processing and good bulk recovery at high temperatures. It can be used as a vehicle cushioning material.

JP-A-6-184898 JP-A-6-304348 JP-A-6-327856 JP 2000-355864 A JP 2008-274473 A

  However, recently, the elasticity and softness required for the cushioning material as well as excellent elasticity, softness, and bulk recovery are required, and preferably higher durability and the conventional non-woven fabric are not available. There is a need for a cushioning material that has one or more of a new tactile sensation, such as a low-resilience (soft) polyurethane foam that is either a tight tactile sensation or a soft tactile sensation.

  In the materials of Patent Documents 1 and 2, the coiled and spring-like latent crimped fibers are thermally fused and entangled with other fibers, so that the latent crimped fibers contributing to elasticity and softness are melted by heat. The coil spring-like shape cannot be maintained, and the coil-spring-like latent crimped fibers or adjacent coil-spring-like crimped portions are heat-sealed. . For these reasons, in the materials of Patent Documents 1 and 2, cushioning properties, elasticity, and softness tend to decrease. In the futon stuffing material of Patent Document 3, since the fibers are not bonded to each other, not only is the volume easily reduced or deformed during use, but also the bulk recovery property tends to be reduced. Moreover, in the material of Patent Document 4, in order to ensure the form stability as a vehicle seat wading material without deteriorating the settling resistance, cushioning property, flexibility, etc., the binder fiber is melted to reveal Although fibers such as crimped fibers and latently crimped fibers are bound to each other, the elasticity and softness of the obtained product are insufficient, and the tactile sensation is not sufficient. Furthermore, Patent Document 5 discloses the use of a nonwoven fabric made of an actual crimpable conjugate fiber as a vehicle cushion material. In the above document, a nonwoven fabric is produced using only an actual crimpable conjugate fiber. In addition, there is no disclosure of a nonwoven fabric using other fibers that has further improved cushioning properties, and a nonwoven fabric made of such an actual crimpable composite fiber also has room for improvement in tactile sensation.

  The present invention has been made in view of such circumstances, and is excellent in elasticity, softness and bulk recovery, and desirably has higher durability and a new tactile sensation not found in conventional nonwoven fabrics, for example, low resilience (softness) ) It was made for the purpose of providing a non-woven fabric having a tactile sensation such as a soft and soft touch such as polyurethane foam, and a cushion material using the same.

  As a result of earnest research, the present inventors use at least two kinds of three-dimensional crimped fibers (first and second three-dimensional crimped fibers) as the fibers used for the nonwoven fabric, and the first three-dimensional crimped fibers. A fiber having a coiled microcrimp having a larger number of crimps than the first three-dimensional crimped fiber, and at least a part of the surface of the first three-dimensional crimped fiber is at least a part of the fibers as a thermal bonding component Heat-bonded to maintain the shape of the coiled microcrimp without substantially melting the second three-dimensional crimped fiber, thereby providing excellent elasticity, softness and bulk recovery, and more The present inventors have found that a nonwoven fabric having high durability and a new tactile sensation not found in conventional nonwoven fabrics can be obtained, and the present invention has been completed.

Therefore, the present invention is a nonwoven fabric comprising a first three-dimensional crimped fiber and a second three-dimensional crimped fiber,
The first three-dimensional crimped fiber is a fiber having a three-dimensional crimp,
The second three-dimensional crimped fiber is a fiber having a coiled micro crimp,
The number of crimps of the first three-dimensional crimped fiber is less than the number of crimps of the second three-dimensional crimped fiber,
At least a part of the surface of the first three-dimensional crimped fiber is a thermal bonding component, and at least a part of the fibers is thermally bonded,
The components constituting the second three-dimensional crimped fiber are not substantially melted,
A nonwoven fabric can be provided.
Moreover, this invention can provide the cushion material using said nonwoven fabric.

  The nonwoven fabric of the present invention and the cushion material, clothing pad, and the like comprising the same are excellent in elasticity, softness, bulk recovery, and have higher durability and softness that are not found in conventional nonwoven fabrics. New tactile sensation can be provided.

FIG. 1 shows a form of mechanical crimping. 2A to 2C show examples of crimped forms of three-dimensional crimped fibers. FIG. 3 shows an example of a crimped form of a three-dimensional crimped fiber. FIG. 4 shows a fiber cross section of the first or second three-dimensional crimped fiber in one embodiment of the present invention. FIG. 5 shows a cut surface obtained by cutting the nonwoven fabric of Example 1 and photographing the cut surface with a scanning electron microscope at a magnification of 80 times. FIG. 6 shows a cut surface obtained by cutting the nonwoven fabric of Comparative Example 3 and photographing the cut surface with a scanning electron microscope at a magnification of 80 times.

  The nonwoven fabric of the present invention includes a first three-dimensional crimped fiber and a second three-dimensional crimped fiber, and the first three-dimensional crimped fiber is a fiber in the nonwoven fabric, with at least a part of the surface serving as a thermal bonding component. The second three-dimensional crimped fiber is a fiber having a coiled (spring-shaped) micro crimp having a larger number of crimps than the first three-dimensional crimped fiber ( In the present specification, the nonwoven fabric of the present invention may be simply referred to as “nonwoven fabric” or “thermal bonding nonwoven fabric”).

  In the non-woven fabric of the present invention, the first three-dimensional crimped fiber that is looser (that is, has a smaller number of crimps) than the second three-dimensional crimped fiber is positive for thermal bonding of fibers in the non-woven fabric. The components of the second three-dimensional crimped fiber having a coiled micro crimp that is involved in the process and that gives elasticity and softness (ie, has a large number of crimps) are substantially deformed by melting. It is characterized by not. Therefore, in the present invention, the shape of the coiled micro crimp that the second three-dimensional crimped fiber is expressed can be maintained in the nonwoven fabric, and as a result, the nonwoven fabric of the present invention has excellent elasticity and softness, It is soft and soft and can have a new tactile feel that is not found in conventional non-woven fabrics.

  Below, the fiber which comprises the nonwoven fabric of this invention, its manufacturing method, etc. are demonstrated.

[First three-dimensional crimped fiber]
The first three-dimensional crimped fiber has a three-dimensional crimp, has a smaller number of crimps than the second three-dimensional crimped fiber (that is, the crimp is loose), and is the first three-dimensional crimped fiber of the first three-dimensional crimped fiber. As long as at least a part of the surface functions as a heat-adhesive component and at least a part of the fibers contained in the nonwoven fabric can be heat-bonded, there is no particular limitation on the configuration, constituent components, manufacturing method, and the like. Here, the term “three-dimensional crimp” is used to distinguish it from a mechanical crimp in which the peak of crimp as shown in FIG. 1 is an acute angle. Specifically, the three-dimensional crimp includes, for example, a crimp having a peak portion curved as shown in FIG. 2A (wave shape crimp), and a crimp having a peak portion curved as shown in FIG. 2B (spiral shape). 2C, a crimp in which a wave shape crimp and a spiral crimp are mixed, an acute crimp of the mechanical crimp shown in FIG. 1 as shown in FIG. 3, and FIG. 2A. As shown in FIG. Of course, the crimp may be a mixture of the mechanical crimp shown in FIG. 1, the wave crimp shown in FIG. 2A, and the spiral crimp shown in FIG. 2B.

  The three-dimensional crimp may be a three-dimensional crimp expressed in a manifest crimpable conjugate fiber. Here, the actual crimpable conjugate fiber expresses a three-dimensional crimp at the fiber stage, and the state of the three-dimensional crimp does not change even when it is subjected to heat treatment, or even if it changes, the degree is small. Fiber. As the first three-dimensional crimped fiber, it is preferable to use a composite fiber in which a sheath component and a core component having a melting point higher than that of the sheath component are included so as to include a predetermined polymer. It is particularly preferred to use fibers. The first three-dimensional crimped fiber that can be used in the present invention has, for example, a low-density polyethylene, a medium-density polyethylene, a high-density polyethylene as a sheath component (first component) in order to express the above-mentioned three-dimensional crimp. Various polyethylenes such as density polyethylene and linear low density polyethylene, ethylene-α olefin copolymers, polyolefin resins such as polypropylene, polybutene-1 and ethylene-vinyl alcohol copolymers, low melting point polyester resins and polyether ester block copolymers Such thermoplastic resins as polyester resins, polyamide resins, and various elastomer resins can be used. Among these, a polyolefin resin is preferable as the first component of the first three-dimensional crimped fiber from the viewpoint that thermal bonding can be easily performed, and a linear shape having a melting point of 130 ° C. or lower is more preferable from the viewpoint of a low melting point. It is preferable to use a component containing low density polyethylene (LLDPE (Linear Low Density Polyethylene)) and use a component containing polyester as the core component (second component). The first component and the second component that can be used in the preferred first three-dimensional crimped fiber of the present invention will be described in detail below, but the first three-dimensional crimped fiber used in the present invention will be described below. It is not limited to a composite fiber containing one component and a second component.

The first component The first component can be used without particular limitation as long as it is a thermoplastic resin that can thermally bond fibers constituting the nonwoven fabric. For example, low density polyethylene, medium density polyethylene, high density polyethylene, linear Polyethylene such as low-density polyethylene, ethylene-α olefin copolymer, polyolefin resin such as polypropylene, polybutene-1, ethylene-vinyl alcohol copolymer, polyester resin such as low melting point polyester resin and polyetherester block copolymer, polyamide Resins and various elastomer resins can be used. Among these, a polyolefin resin is preferable as the first component of the first three-dimensional crimped fiber from the viewpoint that thermal bonding can be easily performed, and a linear shape having a melting point of 130 ° C. or lower is more preferable from the viewpoint of a low melting point. It comprises low density polyethylene (LLDPE). The linear low density polyethylene used in the present invention is not necessarily limited to a low density (generally 0.925 g / cm ³ or less), and is a copolymer obtained by copolymerizing ethylene and an α-olefin. Point to. The α-olefin is generally an α-olefin having 3 to 12 carbon atoms. Specific examples of the α-olefin having 3 to 12 carbon atoms include propylene, butene-1, pentene-1, 4-methylpentene-1, hexene-1, 4-methylhexene-1, heptene-1, and octene. -1, nonene-1, decene-1, dodecene-1 and mixtures thereof. Among these, propylene, butene-1, 4-methylpentene-1, hexene-1, 4-methylhexene-1 and octene-1 are particularly preferable, butene-1 and hexene-1 are more preferable.

  The α-olefin content in the linear low density polyethylene is preferably 1 mol% to 10 mol%, and more preferably 2 mol% to 5 mol%. If the α-olefin content is low, the flexibility of the fiber may be impaired. When the content of α-olefin is increased, the crystallinity is deteriorated, and the fibers may be fused during fiber formation.

Linear low density polyethylene used in the first component, for ^example, preferably has a density of ^{0.88g / cm 3 ~0.94g / cm 3} . When the density is less than 0.88 g / cm ³ , the first component becomes soft, and when it is made into a nonwoven fabric, sufficient bulkiness and bulk recoverability cannot be obtained, and it is inferior in terms of high-speed card properties. May not be obtained. On the other hand, when the density of the linear low density polyethylene is larger than 0.94 g / cm ³ , the bulkiness and bulk recoverability of the nonwoven fabric are improved when the nonwoven fabric is formed, but the surface feel and thickness direction of the nonwoven fabric are improved. Flexibility tends to be inferior. Thus, linear low density polyethylene is preferably ^{0.88g / cm 3 ~0.935g / cm 3} , more preferably ^{0.90g / cm 3 ~0.935g / cm 3} , even more preferably 0.902g / Cm ^{3 to} 0.935 g / cm ³ .

  The linear low density polyethylene has a melting point of 130 ° C. or lower, preferably a melting point in the range of 85 ° C. to 130 ° C., more preferably in the range of 90 ° C. to 128 ° C. Preferably, it is in the range of 100 ° C to 125 ° C. If the melting point of the linear low-density polyethylene is too high, a non-woven fabric having a strength that can withstand practical use may not be obtained when a heat-bonding nonwoven fabric is produced by heat bonding at a low temperature. When the melting point of the linear low density polyethylene is low, when the heat-bonding nonwoven fabric is manufactured by applying the heat-bonding treatment at a high temperature, the surface touch of the nonwoven fabric may be deteriorated, or the high-speed card property is inferior. In some cases, a nonwoven fabric with good formation cannot be obtained.

The linear low density polyethylene having the above density and melting point can be easily obtained by copolymerizing ethylene and α-olefin using a metallocene catalyst. ^However, a density of ^{0.88g / cm 3 ~0.94g / cm 3} , preferably one as long as may have a melting point of the linear low density polyethylene, polymerized with a metallocene catalyst However, for example, a polymerized using a Ziegler-Natta catalyst may be used.

  The melt index (MI) of the linear low density polyethylene is preferably in the range of 1 g / 10 min to 60 g / 10 min in view of spinnability. Here, the melt index (MI) is measured according to JIS K 7210 (1999) (conditions: 190 ° C., load 21.18 N (2.16 kgf)). The larger the MI, the slower the rate of solidification of the sheath component during spinning, and the more easily the fibers are fused. On the other hand, if the MI is too small, fiberization becomes difficult. More specifically, the MI of the linear low-density polyethylene is preferably 2 g / 10 min to 40 g / 10 min, more preferably 3 g / 10 min to 35 g / 10 min, and 5 g / 10 min to 30 g / 10 min. Even more preferably.

  The ratio (Q value: Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) in the linear low density polyethylene is preferably 5 or less. A more preferable Q value is 2 to 4, and even more preferably 2.5 to 3.5. When the Q value is 5 or less, it can be said that the molecular weight distribution of the linear low density polyethylene is narrow, and the linear low density polyethylene satisfying this Q value range is used as the first component. By using it, the 1st solid crimp fiber excellent in the expression property of an actual crimp can be obtained.

  The bending elastic modulus of the linear low density polyethylene is preferably in the range of 25 MPa to 800 MPa in consideration of the properties of the first three-dimensional crimped fiber obtained, the tactile sensation of the obtained nonwoven fabric, and the bulkiness. Here, the flexural modulus is measured according to JIS K 7171 (2008). The first three-dimensional crimped fiber has a soft tactile sensation due to the linear low density polyethylene that is the main component of the first component. Or it may be difficult to obtain a non-woven fabric that is bulky and rich in bulk recovery. Therefore, it is preferable that the linear low density polyethylene is not easily deformed to some extent with respect to bending (that is, it is preferable that the deformation with respect to bending is somewhat high), and specifically, the bending elastic modulus is high. The thing of 25 Mpa or more is preferable. If the flexural modulus of the linear low density polyethylene is too large, the soft tactile sensation may be lost. Therefore, it is preferably 850 MPa or less. More specifically, the flexural modulus of linear low density polyethylene is more preferably 30 MPa to 600 MPa, particularly preferably 35 MPa to 400 MPa, and most preferably 40 MPa to 300 MPa.

  The hardness of the linear low density polyethylene may be in the range of 35 to 70 in consideration of the properties of the obtained first three-dimensional crimped fiber and the feel, bulkiness, and bulk recoverability of the resulting nonwoven fabric. preferable. Here, the hardness of linear low density polyethylene refers to durometer hardness (HDD) measured using a type D durometer in accordance with JIS K 7215 (1986). If the linear low-density polyethylene, which is the main component of the first component, is too soft, the stiffness of the fiber will be lost, and the card passing property of the fiber may be reduced, or it may be difficult to obtain a bulky nonwoven fabric. In some cases, the bulk recovery of the nonwoven fabric may be reduced. Therefore, the linear low density polyethylene preferably has a certain degree of hardness, specifically, a hardness of 38 or more. If the hardness of the linear low density polyethylene is too large, the soft touch may be lost. Therefore, it is preferably 65 or less. More specifically, the hardness of the linear low density polyethylene is more preferably 40 to 63, particularly preferably 43 to 60, and most preferably 45 to 60.

  As long as steric crimps are sufficiently developed in the first three-dimensional crimped fiber and a non-woven fabric that gives a good tactile sensation is provided, the first component further contains other polymer components in addition to the linear low-density polyethylene. May contain. For example, the first component is low density polyethylene (LDPE), high density polyethylene, polypropylene, polybutene, polybutylene, polymethylpentene resin, polybutadiene, propylene copolymer (for example, propylene-ethylene copolymer). ), Polyolefin resins such as ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid copolymer, or ethylene- (meth) acrylic acid methyl copolymer, polyethylene terephthalate , Polyester resins such as polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate and copolymers thereof, and polyamides such as nylon 66, nylon 12 and nylon 6 System resin, engineering plastics such as acrylic resin, polycarbonate, polyacetal, polystyrene and cyclic polyolefins, mixtures thereof, and is selected from such as those elastomeric resin may include one or more polymer components.

  In this invention, it is preferable that a 1st component contains a linear low density polyethylene (LLDPE) and a low density polyethylene (LDPE), and a 1st component is a linear low density polyethylene and a low density as a polymer component. In combination with polyethylene, it is preferable to contain 50% by mass or more, more preferably 75% by mass or more, and more preferably contain only them as polymer components.

  The low density polyethylene (LDPE) that can be contained in the first component is a soft polyethylene having many branches, and is also referred to as a high-pressure polyethylene due to its production method. In the present invention, by adding a small amount of low density polyethylene to the first component as necessary, steric crimps, in particular, manifest crimps, can be expressed more satisfactorily to obtain bulkiness and bulk recovery. And high-speed card performance can be improved. Also, since low density polyethylene is softer than linear low density polyethylene, for example, low-density polyethylene ensures surface texture that tends to decrease when using high-density linear low-density polyethylene. It is also possible to do.

The density of the low density polyethylene is preferably 0.91 g / cm ^{3 to} 0.93 g / cm ³ . The density of low-density polyethylene, since they tend to rely on the MI (190 ° C.) of the polymer, in view of spinnability, the density of the low density polyethylene ^is a 0.915g / cm ³ ~0.92g / cm 3 It is preferable.

  The melting point of the low density polyethylene is preferably 90 ° C to 120 ° C. In the present invention, low-density polyethylene having a low melting point is preferably used. By using low-density polyethylene with a low melting point, steric crimps, particularly manifested crimps, can be expressed more favorably, the thermal processing temperature range during the production of the nonwoven fabric can be widened, and after heat treatment A flexible nonwoven fabric can be obtained. More specifically, the melting point of the low density polyethylene is more preferably 95 ° C to 115 ° C, and particularly preferably 100 ° C to 110 ° C. Moreover, it is preferable that melting | fusing point of low density polyethylene is lower than melting | fusing point of the said linear low density polyethylene. By making the melting point of the low density polyethylene lower than that of the linear low density polyethylene, the linear low density polyethylene functions as a skeleton polymer in the nonwoven fabric, and the low density polyethylene serves as a softening agent. In the nonwoven fabric obtained from the fibers, and therefore, it is preferable because appropriate flexibility can be obtained. The melting point of the low density polyethylene is more preferably 5 ° C. or more lower than the melting point of the linear low density polyethylene, and even more preferably 10 ° C. or more lower than the melting point of the linear low density polyethylene.

  The melt index (MI) of the low density polyethylene is generally preferably in the range of 1 g / 10 min to 60 g / 10 min in view of spinnability. Here, the melt index (MI) is measured according to JIS-K-7210 (1999) (conditions: 190 ° C., load 21.18 N (2.16 kgf)). This is because the larger the MI, the slower the solidification rate of the sheath component during spinning, and the more easily the fibers are fused. On the other hand, if the MI is too small, fiberization becomes difficult. More specifically, the MI of the low density polyethylene is preferably 3 g / 10 min to 50 g / 10 min, more preferably 5 g / 10 min to 50 g / 10 min, and 10 g / 10 min to 50 g / 10 min. Is even more preferred.

  The Q value in the low density polyethylene is preferably 10 or less. A more preferable Q value is 4 to 9, and even more preferably 5 to 8. If the Q value exceeds 10, a good crimped shape may not be obtained, and the adhesive strength tends to be low.

  In the first component, the linear low-density polyethylene and the low-density polyethylene are such that the linear low-density polyethylene occupies 95% to 75% by mass when the combined mass is 100% by mass. It is more preferable that the low density polyethylene is mixed so as to occupy 5% by mass to 25% by mass. Even more preferably, the linear low density polyethylene accounts for 90 mass% to 80 mass% and the low density polyethylene accounts for 10 mass% to 20 mass%. If the proportion of the linear low density polyethylene is too large, it is difficult to obtain the effect of adding the low density polyethylene, and when the nonwoven fabric is used, the nonwoven fabric may be inferior in bulkiness. If the proportion of linear low-density polyethylene is too small, the strength of the nonwoven fabric may be reduced when a heat-bonded nonwoven fabric is obtained.

  When the low-density polyethylene is contained within the above range, the first three-dimensional crimped fiber develops good three-dimensional crimps, reduces variation in the developed crimps, and reduces the crimp ratio of the fibers. To increase. Therefore, the bulkiness of the nonwoven fabric containing this fiber is improved. The reason why steric crimps are likely to appear is not clear, but since long branches of low-density polyethylene are entangled with linear low-density polyethylene molecules with few branches, distortion in stretching is likely to occur, so that steric crimps appear. It is estimated that it becomes easy. However, the present invention is not limited by this estimation. In addition, since the low density polyethylene functions as a softening agent, when the low density polyethylene is included in the above range, for example, when a high density linear low density polyethylene is used, the resulting nonwoven fabric has a thickness direction. Excellent flexibility and surface tactile sensation. Furthermore, when low-density polyethylene is included in the above range, the processing temperature range of the nonwoven fabric can be widened, and a nonwoven fabric having a substantially constant and flexible texture can be obtained regardless of the processing temperature when manufacturing the heat-bonding nonwoven fabric. Can do.

  The first component is a component other than the above polymer component, such as antistatic agent, pigment, matting agent, heat stabilizer, light stabilizer, flame retardant, antibacterial agent, lubricant, plasticizer, softener, antioxidant An additive such as an agent, an ultraviolet absorber, and a crystal nucleating agent may be included. Such an additive is preferably contained in the first component so as to occupy an amount of 10% by mass or less of the entire first component.

Second Component The second component is preferably a component having a melting point higher than the melting point of the first component, and preferably contains polyester as the polymer component. The second component is more preferably a component containing 50% by mass or more of a polyester having a melting point 40 ° C. or more higher than the melting point of the linear low-density polyethylene constituting the first component. The second component preferably contains 50% by mass or more of polyester as the polymer component, more preferably 75% by mass or more, and most preferably 100% by mass.

  Polyester can be preferably used because it is less expensive than other polymers, has high rigidity, and gives the fiber stiffness. Examples of the polyester include polymers such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, and copolymers thereof. The melting point of the polyester is 40 ° C. or more higher than the melting point of the linear low density polyethylene constituting the first component. The melting point of the preferred polyester is a temperature that is 50 ° C. or more higher than the melting point of the linear low density polyethylene.

  Among the polyesters, polyethylene terephthalate and polybutylene terephthalate have higher rigidity than polytrimethylene terephthalate and give the fiber stiffness, so that the resulting high-speed card property of the first three-dimensional crimped fiber can be obtained. Make good. In particular, polyethylene terephthalate is most preferably used because of its high rigidity. Polyethylene terephthalate also has high crystallinity and is difficult to heat shrink by appropriately adjusting the stretching conditions during fiber production, so that it does not exhibit steric crimp, particularly latent crimp, or very A first three-dimensional crimped fiber, shown slightly, can be provided. When a nonwoven fabric is produced using such a first three-dimensional crimped fiber, when the web is subjected to heat treatment, the web does not shrink or slightly shrinks, and the manufacturing process is controlled due to the web shrinkage. Is eliminated or reduced.

  When the second component contains polyethylene terephthalate and / or polybutylene terephthalate as a preferred polyester and other polymer components, the other polymer component is sterically crimped in the first three-dimensional crimped fiber. There is no particular limitation as long as a non-woven fabric that can be sufficiently expressed and the fibers can give a good tactile feel can be provided. For example, other polyester resins, specifically, polyethylene naphthalate, polylactic acid, and polytrimethylene terephthalate may be mixed. However, as described above, polytrimethylene terephthalate is flexible and tends to reduce the high-speed card property of the resulting fiber. Therefore, it is preferably not used in the first three-dimensional crimped fiber.

  The second component is a component other than the above polymer component, such as an antistatic agent, a pigment, a matting agent, a heat stabilizer, a light stabilizer, a flame retardant, an antibacterial agent, a lubricant, a plasticizer, a softener, and an antioxidant. An additive such as an agent, an ultraviolet absorber, and a crystal nucleating agent may be included. Such an additive is preferably contained in the second component so as to occupy an amount of 10% by mass or less of the entire second component.

  In the first three-dimensional crimped fiber, (second component / first component) is preferably 8/2 to 3/7 (volume ratio). More preferably, it is 7/3 to 35/65, and most preferably 6/4 to 4/6. The second component mainly contributes to the bulkiness and bulk recoverability of the nonwoven fabric, and the first component mainly contributes to the strength of the nonwoven fabric and the softness of the nonwoven fabric. When the composite ratio is 8/2 to 3/7, the strength and softness of the nonwoven fabric and the bulk recoverability can be compatible. As the composite ratio increases, the strength of the nonwoven fabric increases, but the resulting nonwoven fabric becomes harder and the bulk recovery tends to be worse. On the other hand, when the amount of the second component is too large, the adhesion point is too small, and the strength of the nonwoven fabric is decreased, so that the bulk recoverability tends to deteriorate.

In the first three-dimensional crimped fiber, the gravity center position of the second component is shifted from the fiber gravity center position in the fiber cross section. FIG. 4 shows a fiber cross section of the first three-dimensional crimped fiber in one embodiment of the present invention. The first component (1) is disposed around the second component (2), and the first component (1) occupies at least 20% of the surface of the first three-dimensional crimped fiber (10) in the fiber cross section. Thereby, the surface of the first component (1) can be at least partially melted during thermal bonding. In the present invention, the second component (2) may be partially melted. In the fiber cross section, the gravity center position (3) of the second component (2) is deviated from the gravity center position (4) of the fiber (10), and the deviation ratio (hereinafter sometimes referred to as the eccentricity ratio). The cross section of the first three-dimensional crimped fiber is magnified with an electron microscope or the like, the center of gravity (3) of the second component (2) in the fiber cross section is C1, and the first three-dimensional crimped fiber (10) When the center of gravity (4) of the fiber in the fiber cross section is Cf and the radius (5) of the fiber cross section of the first three-dimensional crimped fiber (10) is rf, the numerical value represented by the following formula is used.
Eccentricity (%) = [| Cf−C1 | / rf] × 100

  The cross section of the fiber in which the center of gravity (3) of the second component (2) is deviated from the center of gravity (4) of the fiber is preferably an eccentric core-sheath type shown in FIG. Depending on the case, even a multi-core type may be used in which multi-core portions are gathered and are shifted from the center of gravity of the fiber. In particular, an eccentric core-sheath type fiber cross section is preferred in that a desired crimp and / or a three-dimensional crimp such as a spiral crimp can be easily expressed. The eccentricity ratio of the eccentric core-sheath type first three-dimensional crimped fiber is preferably 5% to 50%. A more preferable eccentricity is 7% to 30%. In addition to the circular shape, the shape of the second component in the fiber cross section may be an elliptical shape, a Y shape, an X shape, a well shape, a polygonal shape, a star shape, or the like. The first three-dimensional crimped fiber (10 ) In the fiber cross section may be elliptical, Y-shaped, X-shaped, well-shaped, polygonal, star-shaped, or hollow, as well as circular.

  The first three-dimensional crimped fiber can be produced, for example, by the following procedure. First, a first component containing linear low-density polyethylene and, if necessary, low-density polyethylene, and a second component containing, for example, 50% by mass or more of polyethylene terephthalate and / or polybutylene terephthalate are first in the fiber cross section. Using a composite nozzle in which the component occupies at least 20% of the fiber surface and the center of gravity of the second component deviates from the center of gravity of the fiber, such as an eccentric core-sheath composite nozzle, the second component is spun at the spinning temperature. A spinning filament can be obtained by melt-spinning the first component at a spinning temperature of 200 ° C. to 300 ° C. at 240 ° C. to 350 ° C. and drawing at a take-up speed of 100 m / min to 1500 m / min.

Next, among the polymer components contained in the second component, the draw ratio is a stretch temperature not less than the glass transition point (Tg ₂ ) of the polymer component having the highest glass transition point and less than the melting peak temperature of the linear low density polyethylene. Stretching is performed in the range of 1.5 times to 5.0 times. A more preferable lower limit of the stretching temperature is a temperature 10 ° C. higher than Tg ₂ . A more preferable upper limit of the stretching temperature is 90 ° C., and a particularly preferable upper limit of the stretching temperature is 85 ° C. If the stretching temperature is lower than Tg ₂ , the second component is less likely to crystallize, so the thermal shrinkage of the second component in the resulting fiber increases, or the bulk recovery of the nonwoven fabric made from the resulting fiber decreases. A trend is observed. If the drawing temperature is equal to or higher than the melting peak temperature of the linear low density polyethylene, the fibers are not fused, which is not preferable.

  A more preferred lower limit of the draw ratio is 1.8 times, a particularly preferred lower limit of the draw ratio is 2.0 times, and a most preferred lower limit of the draw ratio is 2.2 times. A more preferred upper limit of the draw ratio is 4.5 times, a particularly preferred upper limit of the draw ratio is 4.0 times, and a most preferred upper limit of the draw ratio is 3.8 times. When the draw ratio is less than 1.8 times, the draw ratio is too low, so it is difficult to obtain a fiber in which three-dimensional crimps such as corrugated crimps and / or spiral crimps are expressed. Not only does the bulkiness become small, but also the rigidity of the fiber itself becomes small, so that it tends to be inferior in non-woven fabric processability such as card passing property or the bulk recovery property is lowered. Moreover, you may perform an annealing process in atmosphere, such as dry heat, wet heat, and steam, at the temperature which 50 to 115 degreeC fibers do not melt | fuse before and after extending | stretching as needed.

  Next, before or after applying the fiber treatment agent as necessary, a crimp of 5/25 mm to 25/25 mm is applied using a known crimping machine such as a stuffing box type crimping machine. The crimped shape after passing through the crimper may be a serrated crimp (mechanical crimp) and / or a corrugated crimp. When the number of crimps is less than 5 pieces / 25 mm, the card passing property tends to deteriorate, and the bulkiness and bulk recoverability of the nonwoven fabric tend to deteriorate. On the other hand, when the number of crimps exceeds 25 pieces / 25 mm, the number of crimps is too large, so the card passing property is lowered, and not only the formation of the nonwoven fabric is deteriorated, but also the initial volume of the nonwoven fabric may be reduced. .

  Furthermore, it is preferable to perform an annealing treatment in an atmosphere of dry heat, wet heat, or steam at 50 ° C. to 115 ° C. after the crimp is applied by the crimper. By the annealing treatment, the expression of the three-dimensional crimp can be promoted in the first three-dimensional crimp fiber. Specifically, after applying the fiber treating agent, crimping is performed with a crimping machine, and the drying process is performed simultaneously with the annealing process in a dry heat atmosphere at 50 ° C. to 115 ° C., thereby simplifying the process. This is preferable because it is possible. If the annealing treatment is less than 50 ° C., the dry heat shrinkage of the resulting fiber tends to increase, and the resulting nonwoven fabric may be disturbed or the productivity may be reduced. Further, when the annealing step also serves as the drying step, if the annealing temperature is less than 50 ° C., the drying of the fibers may be insufficient. By such a method, the first three-dimensional crimped fiber in which the three-dimensional crimp is expressed is obtained.

  In the first three-dimensional crimped fiber thus obtained, the number of crimps (the number of three-dimensional crimps) is smaller than the number of crimps of the second three-dimensional crimped fiber described below, and the card passes through the fiber. In consideration of the bulkiness of the nonwoven fabric and the like, it is preferably 10/25 mm to 22/25 mm. Further, when the number of crimps and the crimp rate of the first three-dimensional crimped fiber were measured according to JIS L 1015 (2010), the ratio of the crimp rate to the number of crimps (crimp rate / crimp The number) is preferably 0.7 to 1.2, more preferably 0.85 to 1. The crimp rate indicates the fixity of the crimp (hardness of crimp), and if the crimp rate / crimp number satisfies the above range, the crimp is difficult to stretch, and the waveform and / Or since it has spiral crimps, the card passing property is good, the web after passing the card maintains the bulkiness, and the nonwoven fabric after the heat treatment can maintain the elasticity.

  The fineness and fiber length of the first three-dimensional crimped fiber are not particularly limited, and are selected according to the method for producing the nonwoven fabric and the use of the nonwoven fabric. For example, when the first three-dimensional crimped fiber is used for manufacturing a heat-bonded nonwoven fabric in which fibers are heat-bonded after a web is produced by a card machine (or other means) as described later, the fineness is 1.1 dtex to 50 dtex, and the fiber length is preferably 10 mm to 110 mm. For example, the fineness of the first three-dimensional crimped fiber may be 2.2 dtex to 30 dtex. More specifically, when the first three-dimensional crimped fiber is a dry nonwoven fabric (for example, an air-through nonwoven fabric, a spunlace nonwoven fabric, or a needle punched nonwoven fabric) produced by producing a fiber web using a card machine, The fiber length suitable for the manufacturing method of non-woven fabric (for example, fiber length 15 mm to 90 mm, more preferably 32 mm to 80 mm), and the fineness suitable for the manufacturing method (for example, fineness 3.3 dtex to 30 dtex, more preferably 5. 6 dtex to 20 dtex). When producing an air laid nonwoven fabric, the fiber length suitable for the production of the air laid nonwoven fabric (for example, 10 mm to 32 mm, more preferably 12 mm to 28 mm), and the fineness suitable for the production method (for example, the fineness of 2.2 dtex to 30 dtex, more Preferably, it may have 3.3 dtex-20 dtex). The fineness can be adjusted as desired by adjusting the fineness and draw ratio of the spun filament. A fiber having a predetermined length is obtained by cutting the fiber after the annealing treatment.

  When the first three-dimensional crimped fiber described above is contained in the nonwoven fabric, it can form a nonwoven fabric with good surface tactile sensation, excellent bulkiness, flexibility in the thickness direction, and bulk recoverability. it can. The first three-dimensional crimped fiber is preferably an actual crimped fiber in which the three-dimensional crimp is manifested in the nonwoven fabric, and constitutes a second three-dimensional crimped fiber described below. Over the range of temperatures at which the components do not substantially melt, the surface of the first three-dimensional crimped fiber, preferably at least a portion of the first component as a heat bonding component, and at least a portion of the fibers contained in the nonwoven fabric are heat bonded. This is preferable.

[Second three-dimensional crimped fiber]
The second three-dimensional crimped fiber is a fiber having a coiled micro crimp in the nonwoven fabric of the present invention. The coiled micro crimp is a spiral three-dimensional crimp as shown in FIG. 2B, and its dimension (particularly, the diameter of the spiral (coil)) is larger than the three-dimensional crimp of the first three-dimensional crimp fiber. It refers to a small one (see reference numeral 12 in FIG. 5). The second three-dimensional crimped fiber is not particularly limited as long as the number of crimps is larger than the number of crimps of the first three-dimensional crimped fiber, and may be a fiber made of one or a plurality of resin components.

Moreover, in the nonwoven fabric of this invention, it is preferable that the component which comprises a 2nd solid crimp fiber is not melt | dissolving substantially. When a part of the second three-dimensional crimped fiber is melted, the shape of the coiled micro crimp is collapsed, or adjacent coiled parts are fused to each other, so that the nonwoven fabric has softness, touch and elasticity. Any one or more are likely to be damaged. Specifically, when the lowest melting point resin melting point among the resin constituting the second three-dimensional crimped fibers was Tm _C, and Tm _C, the melting point of the thermal adhesive component of the first three-dimensional crimped fibers (Tm _B) the temperature difference between _(Tm C -Tm _B) is 5 ° C. or higher, more preferably at 8 ° C. or higher, even more preferably such that 10 ° C. or more, to constitute a second three-dimensional crimped fibers Is preferred. Here, the melting point (Tm _B ) of the thermal bonding component of the first three-dimensional crimped fiber is a temperature at which at least a part of the constituent components of the first three-dimensional crimped fiber starts melting and can be thermally bonded. Point to.

  In general, the second three-dimensional crimped fiber is preferably provided as a latent crimped fiber so that the number of crimps of the microcrimp is larger than that of the first three-dimensional crimped fiber. The meaning of the latent crimped fiber is as described above in relation to the first three-dimensional crimped fiber, and by appropriately selecting the constituent components, it becomes easy to express a coiled microcrimp.

  When the second three-dimensional crimped fiber is a latent crimped fiber, the second three-dimensional crimped fiber has a large difference in heat shrinkability so that a coiled micro crimp can be expressed by heat treatment. It is preferably a composite fiber formed by combining two resin components. The combination of the resin components is not particularly limited, and examples thereof include polyethylene terephthalate / modified polyester, polypropylene / propylene copolymer, and polyester / polyamide.

In the present invention, it is preferable to use a composite fiber containing the first component and the second component as the second three-dimensional crimped fiber,
The first component is, for example, a propylene copolymer whose melting point is 5 ° C. or more higher than the melting point of the linear low density polyethylene contained in the first component of the first three-dimensional crimped fiber, preferably 135 ° C. Including the above propylene copolymer,
The second component includes a thermoplastic resin having a melting point of 145 ° C. or higher,
In the cross section of the composite fiber, the first component occupies at least 20% of the fiber surface;
The melting point of the second component is higher than the melting point of the first component,
The gravity center position of the second component is shifted from the gravity center position of the composite fiber,
A composite fiber is preferably used. Such a composite fiber is because it is easy to express a coiled micro crimp in a nonwoven fabric. Further, such a composite fiber is used when the first three-dimensional crimped fiber is composed of a combination of the above-described linear low density polyethylene / polyester (first component / second component). It is preferably used because it does not substantially melt at the temperature at which the first component of the crimped fiber is thermally bonded. Below, the example of the 2nd solid crimp fiber which consists of a combination of the said specific resin is demonstrated.

First component The first component is, for example, a propylene copolymer whose melting point is 5 ° C. or more higher than the melting point of the linear low density polyethylene contained in the first component of the first three-dimensional crimped fiber, preferably the melting point Includes a propylene copolymer of 135 ° C. or higher. In the present invention, the propylene copolymer is a copolymer containing propylene, such as an ethylene-propylene copolymer, an ethylene-butene (butene-1) copolymer, or an ethylene-propylene-butene (butene-1). In addition to the copolymer, olefinic thermoplastic elastomer (TPO) in which an elastomer component such as ethylene-propylene rubber is finely dispersed in propylene can be used. The propylene copolymer used for the second three-dimensional crimped fiber that can be included in the nonwoven fabric of the present invention is not particularly limited, and a known propylene copolymer can be used, but an ethylene-propylene copolymer or an ethylene-propylene copolymer can be used. It is preferable to use a butene copolymer. The melting point of the propylene copolymer is not particularly limited as long as it is 5 ° C. or more higher than the melting point of the linear low density polyethylene contained in the first component of the first three-dimensional crimped fiber, but it is preferably 8 ° C. or more. More preferably, it is higher by 10 ° C. or more. The specific melting point of the propylene copolymer may be, for example, 125 ° C to 150 ° C, 130 ° C to 145 ° C, or 133 ° C to 143 ° C.

  In the first component, the propylene copolymer is preferably contained in an amount of 60% by mass or more, and more preferably 80% by mass or more. Alternatively, the first component may contain only a propylene copolymer as the polymer component. When the proportion of the propylene copolymer is small, the coiled microcrimp may not be sufficiently developed in the second three-dimensional crimped fiber.

  The first component may contain a polymer component other than the propylene copolymer. In that case, the other polymer component preferably has a melting point equal to or higher than the melting point of the propylene copolymer. If the melting point of the other polymer component is lower than that of the propylene copolymer, a part of the second three-dimensional crimped fiber melts in the nonwoven fabric, and the shape of the coiled micro crimp may be lost. The first component is another polymer component such as polybutene, polybutylene, polymethylpentene resin, polybutadiene, propylene copolymer (for example, propylene-ethylene copolymer), ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate. Polyolefin resin such as copolymer, ethylene- (meth) acrylic acid copolymer, or ethylene- (meth) acrylic acid methyl copolymer, polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, Polyester resins such as polylactic acid, polybutylene succinate and copolymers thereof, polyamide resins such as nylon 66, nylon 12 and nylon 6, acrylic resins, polycarbonate, polyacetal, polystyrene And engineering plastics such as cyclic polyolefins, mixtures thereof, and is selected from such as those elastomeric resin may include one or more polymer components.

  The first component is a component other than the polymer component, such as an antistatic agent, a pigment, a matting agent, a heat stabilizer, a light stabilizer, a flame retardant, an antibacterial agent, a lubricant, a plasticizer, a softener, an antioxidant, and an ultraviolet ray. Additives such as absorbents and crystal nucleating agents may be included. Such an additive is preferably contained in the first component so as to occupy an amount of 10% by mass or less of the entire first component.

Second component The second component is preferably a component having a melting point higher than that of the first component. Specifically, the second component is a polymer component such as polypropylene, polybutene, polybutylene, polymethylpentene resin, polyolefin resin such as polybutadiene, polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, Polyester resins such as polylactic acid, polybutylene succinate and copolymers thereof, polyamide resins such as nylon 66, nylon 12 and nylon 6, engineering plastics such as acrylic resins, polycarbonate, polyacetal, polystyrene and cyclic polyolefin , Mixtures thereof, as well as their elastomeric resins, and the like.

  The second component combined with the propylene-based copolymer preferably includes polypropylene as a polymer component. By combining a propylene-based copolymer and polypropylene, a large number of coiled microcrimps having excellent bondability between the first component and the second component (that is, peeling hardly occurs between the two components) can be expressed. Latent crimped fibers can be obtained.

  When the second component contains polypropylene, the second component preferably contains 60% by mass or more, more preferably 80% by mass or more. Alternatively, the second component may contain only polypropylene as the polymer component. If the proportion of polypropylene is small, the affinity between the second component and the first component may be reduced, and the interface between the first component and the second component will withstand strain caused by heat shrinkage when heat treatment is performed. There is a risk that both components may peel off. In addition, depending on the resin component other than polypropylene, the amount of heat shrinkage during heat treatment may be reduced, and the crimp development may be reduced.

  The first component and the second component may be an eccentric core-sheath type composite fiber (FIG. 4) as described in relation to the first three-dimensional crimped fiber, or constitute a parallel type (side-by-side type) composite fiber. As described above, composite spinning can be performed by appropriately setting spinning conditions and stretching conditions according to the melting points of the first and second components. In order to satisfactorily develop the micro crimp, the second three-dimensional crimped fiber is preferably a side-by-side conjugate fiber.

  When the second three-dimensional crimped fiber is a latent crimped fiber, the state of the fiber (specifically, after producing the fiber web when producing the nonwoven fabric of the present invention, the first three-dimensional crimped fiber The number of crimps before the thermal bonding treatment with the thermal bonding component is preferably 10 pieces / 25 mm to 22 pieces / 25 mm, more preferably 8 pieces / 25 mm to 20 pieces / 25 mm. The problem when the number of crimps is too small or too large is as described for the first three-dimensional crimped fiber. In addition, when the second three-dimensional crimped fiber is a latent crimped fiber, a nonwoven fabric is manufactured, and when the cross section is observed using an electron microscope or the like, the crimp is 3/1 mm to 50/1 mm It is preferable to express a coiled microcrimp by number. With the number of crimps within this range, the second three-dimensional crimped fiber expresses a coiled microcrimp and is dispersed inside the nonwoven fabric, giving the nonwoven fabric a soft feel and a tight feel Can be given to. The number of crimps of the coiled microcrimp in which the second three-dimensional crimped fiber existing inside the nonwoven fabric of the present invention is expressed is preferably 4/1 mm to 40/1 mm, preferably 5/1 mm. It is more preferably ~ 35/1 mm, and even more preferably 7.5 / 1 mm-35 / 1 mm.

  The fineness and fiber length of the second three-dimensional crimped fiber are not particularly limited, and are selected according to the method for producing the nonwoven fabric and the use of the nonwoven fabric. For example, when the second three-dimensional crimped fiber is used for manufacturing a heat-bonded nonwoven fabric in which fibers are heat-bonded after a web is produced by a card machine (or other means) as described later, the fineness is It is preferable that the short fiber has a length of 0.8 dtex to 20 dtex and a fiber length of 10 mm to 110 mm. For example, the fineness of the first three-dimensional crimped fiber may be 1.1 dtex to 10 dtex, and may be 1.4 dtex to 5.6 dtex. When the second sterically crimped fiber is a latently crisp fiber that develops steric crimps during heat treatment, if the fineness is too large, the expression of microcrimps is reduced, and the desired number of crimps cannot be expressed. Not only there is a fear, but it becomes difficult to entangle the first three-dimensional crimped fiber and / or the third three-dimensional crimped fiber, so that the tactile sensation and cushioning property of the resulting nonwoven fabric may be lowered. Therefore, when the second three-dimensional crimped fiber is a latent crimped fiber, its fineness is preferably 0.8 dtex to 5.6 dtex, more preferably 1.1 dtex to 5.0 dtex. Even more preferably, it is 8 dtex to 4.5 dtex. When the fiber length of the second three-dimensional crimped fiber is a dry nonwoven fabric (for example, an air-through nonwoven fabric, a spunlace nonwoven fabric, a needle punched nonwoven fabric, etc.) produced by producing a fiber web using a card machine, The fiber length suitable for the production method is 15 mm to 90 mm, more preferably 32 mm to 80 mm. When manufacturing an airlaid nonwoven fabric, it is 10 mm-32 mm suitable for manufacture of an airlaid nonwoven fabric, More preferably, it shall be 12 mm-28 mm. The fineness can be adjusted as desired by adjusting the fineness and draw ratio of the spun filament. A fiber having a predetermined length is obtained by cutting the fiber after the annealing treatment.

[Third three-dimensional crimped fiber]
In addition to the first three-dimensional crimped fiber and the second three-dimensional crimped fiber, the nonwoven fabric of the present invention may further include a third three-dimensional crimped fiber (in the present specification, “matrix fiber”). May be included). The optional third three-dimensional crimped fiber that can be contained in the nonwoven fabric of the present invention does not contain a component that melts at a temperature at which the heat-bonding component of the first three-dimensional crimped fiber heat-bonds the fibers. If it does not participate in adhesion, there is no particular limitation. Therefore, among the thermoplastic resins contained in the third three-dimensional crimped fiber, the linear low density that can be contained in the first component of the first three-dimensional crimped fiber is the melting point of the thermoplastic resin having the lowest melting point. It is preferably 20 ° C. or higher than the melting point of polyethylene. The difference from the melting point of the linear low density polyethylene is preferably 30 ° C. or more, more preferably 50 ° C. or more. The third three-dimensional crimped fiber is preferably an actual crimped fiber, and more specifically, a polyester resin, a polyolefin resin, a polyamide resin, an acrylic resin, a polycarbonate, a polyacetal, polystyrene, a cyclic polyolefin, and the like A fiber composed of engineering plastics or the like is preferable. The third three-dimensional crimped fiber includes one or more of the above resins, or a combination of two or more (may be the same or different), a core-sheath type composite fiber or an eccentric core-sheath type It may be a composite fiber or a side-by-side type composite fiber. Among these, since it is required that the first three-dimensional crimped fiber does not melt at a temperature at which the first component of the first three-dimensional crimped fiber melts or a temperature at which the second three-dimensional crimped fiber develops the three-dimensional crimp, The crimped fiber preferably contains at least one resin selected from polyester resins and polyamide resins, and more preferably contains at least one polyester resin. The third three-dimensional crimped fiber preferably has a number of crimps of 5/25 mm to 25/25 mm. Further, the fineness and fiber length of the third three-dimensional crimped fiber are the same as described for the first three-dimensional crimped fiber, and thus detailed description thereof is omitted here.

[Manufacture of non-woven fabric]
Then, the nonwoven fabric of this invention is demonstrated with the manufacturing method. The production of the nonwoven fabric of the present invention starts with weighing the mass of each three-dimensional crimped fiber that can be contained in the nonwoven fabric. Specifically, the content of the first three-dimensional crimped fiber (based on the total mass of the nonwoven fabric) is preferably 20% by mass or more, more preferably 25% by mass to 80% by mass, and still more preferably. Weigh the first three-dimensional crimped fiber so that it is 25 mass% to 70 mass%, and even more preferably 30 mass% to 70 mass%. The content of the second three-dimensional crimped fiber (based on the total mass of the nonwoven fabric) is preferably 5% by mass or more, more preferably 10% by mass to 55% by mass, and even more preferably 15% by mass to The mass of the second three-dimensional crimped fiber is weighed so that it is 55% by mass, even more preferably 15% by mass to 45% by mass. About 3rd solid crimped fiber, the content (based on the total mass of a nonwoven fabric) is 0 mass%-75 mass%, Preferably it is 10 mass%-75 mass%, More preferably, it is 15 mass%-60 The mass of the third three-dimensional crimped fiber is weighed so as to be 15% by mass, more preferably 15% by mass to 55% by mass. However, the total content of the first, second and third three-dimensional crimped fibers does not exceed 100% by mass.

If the content of the first three-dimensional crimped fiber is less than 20% by mass, the proportion of the thermal adhesive component that thermally bonds the constituent fibers in the nonwoven fabric decreases, so that the constituent fibers are not sufficiently thermally bonded. In addition, the shape may be deformed and deformed during use, and there is a risk of problems such as loss of bulk recovery and cushioning.
If the content of the second three-dimensional crimped fiber is less than 5% by mass, there is a possibility of problems such as being unable to obtain elasticity that is soft and soft and fits to the hand.
If the content of the third three-dimensional crimped fiber exceeds 75% by mass, the ratio of the first three-dimensional crimped fiber is too small, and there is a risk of problems such as deterioration in touch and shape loss during use. .

  In addition to the first, second, and third three-dimensional crimped fibers, if other fibers are used as necessary, the other fibers include, for example, cotton, silk, wool, hemp, pulp, etc. One or more fibers can be selected from natural fibers, regenerated fibers such as rayon and cupra, and synthetic fibers such as acrylic, polyester, polyamide, polyolefin and polyurethane. it can. Other fibers may be used in combination with the first, second and third three-dimensional crimped fibers, or a fiber web comprising the first, second and third three-dimensional crimped fibers. And may be used in a stacked manner.

  In the production of the nonwoven fabric of the present invention, it is preferable that the first and second three-dimensional crimped fibers are mixed, and if necessary, the third three-dimensional crimped fibers and other fibers are mixed to produce a fiber web. . Examples of fiber webs used in producing the nonwoven fabric include card webs such as parallel webs, semi-random webs, random webs, cross webs, and Chris cross webs, airlaid webs, wet papermaking webs, and spunbond webs. Is mentioned. Two or more different types of fiber webs may be laminated.

  Next, it is preferable to heat-treat the fiber web and thermally bond the fibers with the first three-dimensional crimped fiber. In order to entangle the fibers, the fiber web may be subjected to entanglement treatment such as needle punch treatment or hydroentanglement treatment before and / or after the heat treatment, if necessary.

  In order to obtain a heat-bonding nonwoven fabric, the fiber web is subjected to heat treatment by a known heat treatment means. As the heat treatment means, a heat treatment machine in which pressure such as wind pressure is not so much applied to the fiber web, such as a hot air penetration type heat treatment machine, a hot air blowing type heat treatment machine and an infrared heat treatment machine, is preferably used. The heat treatment conditions such as the heat treatment temperature are such that the heat-bonding component of the first three-dimensional crimped fiber, particularly the first component is sufficiently melted and / or softened, and the fibers are joined at the contact or intersection point. The conditions are selected so that the three-dimensional crimps generated in the crimped fibers are not crushed. Furthermore, when the second three-dimensional crimped fiber is a latent crimped fiber, the heat treatment is preferably carried out by selecting conditions under which the three-dimensional crimp is expressed in the second three-dimensional crimped fiber. For example, the heat treatment temperature is the melting peak temperature before spinning of the linear low density polyethylene (the linear chain having the highest melting peak temperature when a plurality of linear low density polyethylenes are included in the first component). When the melting peak temperature of the low-density polyethylene is Tm, the temperature is preferably Tm ° C. to (Tm + 40) ° C. A more preferable heat treatment temperature range is (Tm + 5) ° C. to (Tm + 30) ° C.

  In the heat-bonded nonwoven fabric of the present invention, at least a part of the surface of the first three-dimensional crimped fiber, preferably at least a part of the first component functions as a heat-bonded component, and at least a part of the fibers contained in the nonwoven fabric is formed. Although thermally bonded, in the present invention, the component constituting the second three-dimensional crimped fiber, particularly the component constituting the coiled microcrimp (the first component and the second component of the second three-dimensional crimped fiber, It is particularly preferable that the first component) is not substantially melted. Here, the components constituting the second three-dimensional crimped fiber are not substantially melted when the surface of the nonwoven fabric or a cut section is observed using a scanning electron microscope or an optical microscope. It means that the components of the second three-dimensional crimped fiber are hardly melted and the shape of the coiled micro crimp is maintained. And in the nonwoven fabric of the present invention, the first three-dimensional crimped fibers are involved in the adhesion between the fibers, and by maintaining the shape of the coiled micro crimp of the second three-dimensional crimped fibers, excellent elasticity and Softness as well as a new unprecedented tactile feel can be provided.

As compression characteristic values, compression energy (sometimes called compression work, hereinafter also referred to as WC (gf · cm / cm ² )), compression recovery (compression resilience, compression recovery rate, sometimes referred to below) , Also referred to as RC (%)). WC indicates the work of compression. The larger this is, the softer in the thickness direction, the easier it is to compress. RC shows elasticity (recoverability, resilience) against compression, and the greater this, the easier it is to rebound against compression, i.e., cushioning. Since the compression energy is small to some extent, that is, it is deformed while being repelled to some extent when it is compressed, it shows a tight tactile sensation when pushed and deformed by hand. In addition, since the heat-bonding nonwoven fabric of the present invention has a high compression recovery property, it has elasticity against compression and exhibits a good cushioning property. The apparatus for measuring the compression characteristic value obtained from the behavior of the load-displacement curve at the time of the compression test is not particularly limited as long as the apparatus can measure the compression characteristic value based on KES. The compression characteristic value can be measured, for example, by using a KES-G5 handy compression tester or a KES-FB3-AUTO-A automated compression tester (both manufactured by Kato Tech Co., Ltd.).

The heat-bonded nonwoven fabric of the present invention not only has a large initial bulk, but is soft and easily compressed when a load is applied. And when a load is removed or when a load becomes small, it repels and it has the characteristics that the bulk of a heat bondable nonwoven fabric recovers rapidly. In order to show these characteristics at the time of compression and release, WC and RC are important among the compression characteristic values based on the KES. In the heat-bonded nonwoven fabric of the present invention, the compression energy (WC) is, for example, 250 gf · cm / cm ² or less, preferably 20 gf · cm / cm ^{2 to} 220 gf · cm / cm ² , more preferably 30 gf · cm / cm ^2. ~ 135 gf · cm / cm ² . When the compression energy (WC) is 250 gf · cm / cm ² or less, the nonwoven fabric does not become excessively soft, and when compressed, it deforms while giving some resistance, so that it gives a tight feel as well as a feeling of elasticity. become. If it exceeds 250 gf · cm / cm ² , the non-woven fabric becomes excessively soft, so the touch is too light, and it is difficult to obtain a tight feeling when compressed, or the resilience and cushioning properties are poor. There is a fear.

  In the heat-bonded nonwoven fabric of the present invention, the compression recovery rate (RC) is preferably 45% or more, for example. When the compression recovery rate (RC) is 45% or more, the bulk recovery property of the nonwoven fabric becomes high, and it is easy to return to the original shape when the compressed state is released, which is preferable when used as a cushioning material. In addition, it is estimated that when pushing the nonwoven fabric by hand because it is easy to return bulk, it comes to moderately repel, combined with a relatively low compression energy, creating a tight feel, You are not bound by such a theory. If the compression recovery rate is less than 45%, it is presumed that the return of the bulk when the compressed state is released becomes insufficient, the cushioning property may be deteriorated, and a tight tactile sensation cannot be obtained. You are not bound by such a theory. The compression recovery rate is preferably 50% or more. The upper limit of the compression recovery rate (RC) is not particularly limited, and may be 100%, 90%, or 85%.

  The non-woven fabric of the present invention has excellent elasticity and softness, and has a new and unprecedented tactile feel, so that it is a cushioning material (for example, for automobiles, aircraft, railway vehicles, ships) In addition to cushion materials used for seats, etc., cushion materials used for general household and office seats, and cushion materials placed under the top sheet in absorbent articles such as sanitary napkins, paper diapers, and nursing paper diapers Suitable for uses such as clothing pads (e.g., female bra pads, shoulder pads, elbow pads, knee pads), bedding (e.g., beds, bed mats, mattresses, futons, pillows, etc.) In addition, since it is bulky and rich in elasticity and bulk recovery properties, it is suitable for applications such as a sound absorbing material, a sound insulating material, a vibration insulating material, a vibration damping material, a heat insulating material, and a heat insulating material.

When using the heat-bonding nonwoven fabric of the present invention such as various vehicle cushioning material, as the thickness of 1cm or more cushioning material, its density ^is preferably set to ^{5kg / m 3 ~100kg / m 3} , 10kg / m 3 ~ more preferably to 80 kg / ^{m 3,} and particularly preferably to ^{12kg / m 3 ~40kg / m 3} . However, the density may be outside these ranges depending on the type of cushioning material. Moreover, when using the thermobonding nonwoven fabric of this invention for another use, the density is suitably selected according to the use.

  When using the heat-bonding nonwoven fabric of the present invention as a cushioning material, the content of the first three-dimensional crimped fiber is 30% by mass to 70% by mass and the content of the second three-dimensional crimped fiber is based on the total mass of the nonwoven fabric. 15 mass% to 55 mass%, and the content of the third three-dimensional crimped fiber is 15 mass% to 55 mass% (however, the total of the contents of the first, second and third three-dimensional crimped fibers) Is preferably not more than 100% by mass). When the ratio of the first, second, and third three-dimensional crimped fibers is within the above range, the resulting heat-bonded nonwoven fabric is rich in initial volume, becomes a nonwoven fabric with high bulk recoverability, and is suitable for cushion materials. It becomes. In addition, as long as the first, second, and third three-dimensional crimped fibers do not deviate from the respective ranges, the tactile sensation and elasticity can be adjusted by adjusting the blending ratio of the fibers. For example, by increasing the proportion of the first three-dimensional crimped fibers, the thermal bonding between the fibers is strengthened, and the resulting nonwoven fabric can be a highly durable nonwoven fabric. Also, by increasing the proportion of the second three-dimensional crimped fiber, the nonwoven fabric contains a lot of fibers that express coiled microcrimps, and these fibers are deformed during compression and recovery. Therefore, it can be easy to show a tight feel. By increasing the proportion of the third three-dimensional crimped fiber, thermal bonding between fibers is difficult to proceed, and the proportion of heat shrinkage during heat treatment is also reduced, so that a thick nonwoven fabric can be easily obtained and softly The effect that it becomes easy to obtain the nonwoven fabric of the tactile sensation which was made can be anticipated.

[Examples 1-7, Comparative Examples 1-4]
(First three-dimensional crimped fiber)
The following three-dimensional crimped fibers 1A and 1B were prepared as first three-dimensional crimped fibers used in Examples and Comparative Examples of the present invention.

Solid crimped fiber 1A
As a first component, linear low density polyethylene (LLDPE) (melting point: 121 ° C., density: 0.931 g / cm ³ , melt index (MI): 20 g / 10 min, flexural modulus: 600 MPa, hardness: 60 (Ube) Maruzen Polyethylene Co., Ltd. ZM076)) (85 mass%) and low density polyethylene (LDPE (melting point: 106 ° C., density: 0.918 g / cm ³ ), melt index (MI): 22 g / 10 min, flexural modulus: 130 MPa, Hardness: 46 (Japan Polyethylene Co., Ltd. LJ802) (15% by mass)) (in parentheses, mixing ratio (% by mass)), polyethylene terephthalate (PET) as the second component (melting point: 250 ° C., intrinsic viscosity value) (IV value) 0.64 (manufactured by Toray Industries, Inc., T200E)) Using an eccentric sheath / core composite nozzle (600 holes), the first component / second component ratio (volume ratio) is 55/45, the sheath component spinning temperature is 290 ° C., and the core component spinning temperature is 340 ° C. The melt was extruded at a nozzle temperature of 290 ° C. to obtain a spun filament having an eccentricity of 25% and a fineness of 15.5 dtex.

  The obtained spinning filament was stretched 3.6 times in hot water at 70 ° C. to obtain a stretched filament having a fineness of about 6.0 dtex (fiber strength 2.18 cN / dtex). Next, after applying a water-repellent fiber treatment agent so that the adhesion amount is 0.3% by mass with respect to the mass of the fiber, 15.9 pieces / mechanical crimps are applied to the drawn filament with a stuffing box type crimper. It applied so that it might become 25 mm (crimp rate 11.3%). And the annealing process and the drying process were simultaneously performed in the relaxed state for about 15 minutes with the hot air spraying apparatus set to 100 degreeC. Thereafter, the filament was cut into a fiber length of 64 mm to obtain an actual crimpable composite short fiber (1A) (crimp number: 15.9 pieces / 25 mm).

Solid crimped fiber 1B (for comparison)
As a first component, polybutene-1 (PB-1) (manufactured by Sun Allomer Co., Ltd. DP0401M (melting point: 123 ° C., MFR (190 ° C.) 20 g / 10 min)) (96% by mass) and linear low density polyethylene (LLDPE) ( NJ744N (melting point 120 ° C., MFR (190 ° C.) 12 g / 10 min) (4% by mass) (4% by mass in parentheses) is used as a second component, and polyethylene terephthalate (PET) ( Melting point: 250 ° C., intrinsic viscosity value (IV value) 0.64 (T200E, manufactured by Toray Industries, Inc.)), and using these two components, an eccentric sheath core type composite nozzle (600 holes) The composite ratio (volume ratio) of one component / second component is 55/45, the spinning temperature of the sheath component is 250 ° C., the spinning temperature of the core component is 320 ° C., and the nozzle temperature Melt-extruded as 290 ° C., eccentricity of 25%, to obtain a spinning filament having a fineness of 11 dtex.

  The obtained spinning filament was stretched 2.3 times in hot water at 80 ° C. to obtain a stretched filament having a fineness of about 6.0 dtex (fiber strength 2.33 cN / dtex). Next, after applying a water-repellent fiber treatment agent so that the attached amount is 0.3% by mass with respect to the mass of the fiber, 14.3 pieces / 25 mm of mechanical crimps are applied to the drawn filaments using a stuffing box type crimper. (Crimping rate was 13.4%). And the annealing process and the drying process were simultaneously performed in the relaxed state for about 15 minutes with the hot air spraying apparatus set to 100 degreeC. Thereafter, the filament was cut into a fiber length of 64 mm to obtain an actual crimpable composite short fiber (1B) (number of crimps: 15.5 / 25 mm).

(Second solid crimped fiber)
The following three-dimensional crimped fibers 2A, 2B, and 2C were prepared as the second three-dimensional crimped fibers used in Examples and Comparative Examples of the present invention.

Solid crimped fiber 2A
Side-by-side latent crimpable composite fiber (Daiwabo Polytech Co., Ltd.) using ethylene-propylene copolymer (melting point: 138 ° C) as the first component and polypropylene (melting point: 161 ° C) as the second component. Product name “CPP” fineness 2.2 dtex, fiber length 51 mm) was used.

Solid crimped fiber 2B
Latent crimped conjugate fiber manufactured using the same resin as the above-mentioned three-dimensional crimped fiber 2A and having a fineness adjusted to 6.0 dtex (trade name “CPP” fineness 6.0 dtex, fiber length 51 mm, manufactured by Daiwabo Polytech Co., Ltd.) It was used.

Solid crimped fiber 2C (for comparison)
Side-by-side latent crimpable composite fiber (Daiwabo Polytech Co., Ltd.) using linear low density polyethylene (melting point: 116 ° C.) as the first component and polypropylene (melting point: 161 ° C.) as the second component. Product name “NBF (L) V” fineness 2.3 dtex, fiber length 51 mm) was used.

(Third three-dimensional crimped fiber)
The following three-dimensional crimped fiber 3A was prepared as a third three-dimensional crimped fiber used in Examples and Comparative Examples of the present invention.

Three-dimensional crimped fiber 3A
Polyester-based composite fiber (H38F manufactured by Unitika Ltd. (conjugate PET fiber, side-by-side type, fineness 6.7 dtex, fiber length 51 mm, crimp number: 9.7 pieces / 25 mm)

(Manufacture of non-woven fabric)
Nonwoven fabrics of Examples 1 to 7 and Comparative Examples 1 to 3 of the present invention were produced as follows.
The first, second and third three-dimensional crimped fibers were each weighed so as to have a blending ratio (mixing ratio) shown in Table 1 below. Next, each of the weighed fibers (raw cotton) is opened, and the first, second and third three-dimensional crimped fibers are sufficiently mixed (mixed cotton), and thereafter a basis weight of about 40 g / m ² is obtained using a parallel card machine. 9 card webs were prepared. This card web was laminated to obtain a card web having a basis weight of about 360 g / m ² . This card web is adjusted to have a thickness of 20 mm (16 mm in Comparative Example 1) and is set to a predetermined temperature (145 ° C. in Comparative Examples 1 and 2; 135 ° C. otherwise). For 40 seconds to obtain a heat-bonded nonwoven fabric having a basis weight of about 400 g / m ² .

[Comparative Example 4]
As Comparative Example 4, a commercially available black flexible urethane foam (hereinafter simply referred to as urethane foam) used for applications such as shock absorbing cushion materials and sound absorbing materials was prepared. This urethane foam has a basis weight of 300 g / m ² , a thickness of 1 cm, and a density of 30 kg / m ³ .

(Evaluation of non-woven fabric)
The following evaluation was performed on the heat-bonded nonwoven fabric (hereinafter simply abbreviated as “non-woven”) and urethane foam (Comparative Example 4) obtained in Examples 1 to 7 and Comparative Examples 1 to 4 of the present invention. .

[The number of crimps of the second three-dimensional crimped fiber (the number of crimps of the micro crimp)]
The surface of the obtained non-woven fabric is observed at 30 to 80 times using a scanning electron microscope, and about three or more different crimped fibers in which microcrimps are expressed, crimps per mm for different five or more fibers. The number was measured, and the average value was defined as the number of crimps of the second three-dimensional crimped conjugate fiber in the sample.

[Elasticity]
The “elasticity” of the nonwoven fabric was evaluated according to the following criteria.
○: Rebounding when pressed with hand.
Δ: When pressed by hand, repulsive force is felt, but bounce rebound is poor.
X: When pressed by hand, no bouncy resilience is felt.

[Softness]
The “softness” of the nonwoven fabric was evaluated according to the following criteria.
○: Soft and can be deformed with light force.
(Triangle | delta): There exists a repulsive force and a nonwoven fabric will not deform | transform, if it does not hold down a little.
X: The surface is hard and the nonwoven fabric does not deform unless pressed firmly.

[Must feel]
The “feel of stickiness” of the nonwoven fabric was evaluated according to the following criteria.
○: When pressed with your hand, it deforms so that it fits in your hand and sticks to your hand.
Δ: When pressed by hand, feels repulsive force and is not familiar to the hand.
X: Feels repulsive force when pushed by hand and has no familiarity with hand.

[Compression energy (WC) and compression recovery rate (RC)]
A compression test was performed on the thermally bonded nonwoven fabric, and compression energy (WC) and compression recovery rate (RC) were measured as compression characteristic values from a load-displacement curve. A KES-G5 handy compression tester manufactured by Kato Tech Co., Ltd. was used for the compression test and measurement of the compression characteristic value for the heat-bonded nonwoven fabric. At the time of measurement, a circular pressure plate having an area of 2 cm ² was used as a compressor, SENS: 2 and DEF sensitivity: 20 were set, and the compression rate of the compressor was 0.02 cm / sec with respect to the heat-bonded nonwoven fabric. And compressed until the load reached 50 gf / cm ² . After the load reached 50 gf / cm ² , compression was removed so that the moving speed of the compressor was 0.02 cm / sec, and the compression characteristic value was measured. The measurement results are shown in Table 1 below.

  The structures, physical properties and evaluation results of the nonwoven fabrics obtained in Examples 1 to 7 and Comparative Examples 1 to 3 are summarized in Table 1 below.

  Examples 1 to 7 of the present invention include a first three-dimensional crimped fiber and a second three-dimensional crimped fiber, and the second three-dimensional crimped fiber does not contribute to thermal bonding between the fibers, It can be seen that the nonwoven fabric in which the fibers are thermally bonded with the three-dimensional crimped fibers becomes a nonwoven fabric excellent in softness and bulk recovery. In particular, the nonwoven fabrics of Examples 1 to 4 and Example 6 were all evaluated well for elasticity, softness, and a feeling of stickiness. FIG. 5 shows a state in which a cross section of the nonwoven fabric of Example 1 is observed with a scanning electron microscope. In this nonwoven fabric, the second three-dimensional crimped fiber expresses a coil-shaped microcrimp and is not substantially melted, and the second three-dimensional crimped fiber maintains the above-mentioned shape while maintaining the above shape. It can be confirmed that the three-dimensional crimped fibers and / or the third three-dimensional crimped fibers are entangled or thermally bonded by the first three-dimensional crimped fibers. By the presence of the first three-dimensional crimped fiber and the second three-dimensional crimped fiber, the constituent fibers of the nonwoven fabric are brought into direct contact with each other to be bonded or entangled to form a network, and a coiled micro crimp is formed. By forming a network through the expressed second three-dimensional crimped fiber, it is considered that the soft and dry feel unique to the nonwoven fabric of the present invention is generated.

  The nonwoven fabric of Example 7 is excellent in softness and feeling of stickiness, but its elasticity is slightly lowered. This is because the second three-dimensional crimped fiber used in Example 7 was larger in fineness than the other examples, so that it was difficult to entangle with other fibers, and the fibers were connected by micro crimped fibers. It is presumed that this was due to the failure to do so.

  Compared with Examples 1-7, the nonwoven fabric of Comparative Examples 1-3 has low evaluation of a sensory test. In Comparative Example 1, the evaluation of softness was low, and the evaluation of stickiness was not good. In Comparative Example 1, since heat treatment was performed at 145 ° C. exceeding the melting point (138 ° C.) of the propylene copolymer contained in the second three-dimensional crimped fiber, the first three-dimensional crimped fiber strongly heats the fibers. In addition to being bonded, a part of the propylene copolymer contained in the second three-dimensional crimped fiber is melted, the micro crimp shape is lost, or the entire nonwoven fabric is hardened by heat bonding between the fibers. It is presumed that

  When heat treatment is performed at a temperature higher than the melting point of the thermoplastic resin constituting the first component of the second three-dimensional crimped fiber, the loss of the micro crimp shape can be confirmed by observing the cross section of the nonwoven fabric. The mode that the cross section of the nonwoven fabric of the comparative example 3 was observed with the scanning electron microscope in FIG. Since this nonwoven fabric was heat-treated at a temperature exceeding the melting point (116 ° C.) of the first component of the second three-dimensional crimped fiber, the second three-dimensional crimped fiber was cut, and the fiber diameter was partially reduced. "Can be confirmed (see reference numeral 14 in FIG. 6). In the nonwoven fabric of Comparative Example 3, the number of crimps of the microcrimp in which the second three-dimensional crimped fiber is expressed is smaller than in Examples 1-7. This is because when the nonwoven fabric of Comparative Example 3 was produced, the second three-dimensional crimped fiber was obtained by performing heat treatment at a temperature higher than the melting point of the first component (sheath component) of the second three-dimensional crimped fiber. This is probably because the deformation and the loss of the shape of the micro crimp resulted in loose crimps and a reduced number of crimps per fixed length.

  In addition, it can also be seen from Comparative Example 2 that when heat treatment is performed at a temperature exceeding the melting point of the first component of the second three-dimensional crimped fiber, a nonwoven fabric excellent in elasticity and tactile sensation like the nonwoven fabric of the present invention cannot be obtained. I can confirm. In this nonwoven fabric, heat treatment is performed at 145 ° C., which is higher than the melting point of the first component of the first three-dimensional crimped fiber. As a result, the second solid crimped fiber was also thermally bonded, and it was considered that the elasticity and tactile sensation obtained with the non-woven fabric including the fiber expressing the microcrimp could not be obtained.

Furthermore, when the nonwoven fabrics of Examples 1 to 7 and a commercially available black flexible urethane foam (hereinafter simply referred to as urethane foam) were compared, a large difference in tactile sensation could be confirmed. The difference between the non-woven fabric of the present invention and urethane foam in the tactile sensation is that the non-woven fabric of the present invention has a stretchable structure due to the expression of microcrimps, whereas urethane foam does not have such a structure. It can be inferred that there was a difference in feeling. In addition, since the urethane foam was touched by hand and felt resistance when compression was started and the touch was hard, the result was inferior in softness compared to the nonwoven fabric of the present invention. Furthermore, the urethane foam has a density of 30 kg / m ³ , and has the highest density in Examples 1 to 7 and Comparatives 1 to 4, and is used in comparison with a nonwoven fabric cushion material in applications where weight reduction is required. It can be confirmed that it is difficult.
The disclosure of the present specification may include the following aspects.
(Aspect 1)
A nonwoven fabric comprising a first three-dimensional crimped fiber and a second three-dimensional crimped fiber,
The first three-dimensional crimped fiber is a fiber having a three-dimensional crimp,
The second three-dimensional crimped fiber is a fiber having a coiled micro crimp,
The number of crimps of the first three-dimensional crimped fiber is less than the number of crimps of the second three-dimensional crimped fiber,
At least a part of the surface of the first three-dimensional crimped fiber is a thermal bonding component, and at least a part of the fibers is thermally bonded,
The components constituting the second three-dimensional crimped fiber are not substantially melted,
Non-woven fabric.
(Aspect 2)
The first non-woven fabric according to aspect 1, wherein the first three-dimensional crimped fiber is an actual crimped fiber in which the three-dimensional crimp is actualized.
(Aspect 3)
The first three-dimensional crimped fiber is a composite fiber containing a first component and a second component,
The first component includes linear low density polyethylene (LLDPE) having a melting point of 130 ° C. or lower,
The second component includes polyester,
In the cross section of the composite fiber, the first component occupies at least 20% of the fiber surface;
The melting point of the second component is higher than the melting point of the first component,
The gravity center position of the second component is shifted from the gravity center position of the composite fiber,
The nonwoven fabric of aspect 2.
(Aspect 4)
The second three-dimensional crimped fiber is a latent crimped fiber, and the nonwoven fabric according to any one of aspects 1 to 3, wherein the micro crimp is formed by the expression of the latent crimp.
(Aspect 5)
The second three-dimensional crimped fiber is a composite fiber containing a first component and a second component,
The first component includes a propylene copolymer having a melting point of 135 ° C. or higher,
The second component includes a thermoplastic resin having a melting point of 145 ° C. or higher,
In the cross section of the composite fiber, the first component occupies at least 20% of the fiber surface;
The melting point of the second component is higher than the melting point of the first component,
The gravity center position of the second component is shifted from the gravity center position of the composite fiber,
The nonwoven fabric according to aspect 4.
(Aspect 6)
When the lowest melting point resin melting point among the resin constituting the second three-dimensional crimped fibers and Tm _C, and Tm _C, the melting point of the thermal bonding component of the first three-dimensional crimped fibers and (Tm _B) the temperature difference _(Tm C -Tm _B) is 5 ° C. or more, nonwoven fabric according to any of embodiments 1-5.
(Aspect 7)
Furthermore, the nonwoven fabric in any one of aspects 1-6 containing a 3rd three-dimensional crimped fiber.
(Aspect 8)
Based on the total mass of the nonwoven fabric,
The content of the first three-dimensional crimped fiber is 30% by mass to 70% by mass,
The content of the second three-dimensional crimped fiber is 15% by mass to 55% by mass,
The content of the third three-dimensional crimped fiber is 15% by mass to 55% by mass,
The total content of the first, second and third three-dimensional crimped fibers does not exceed 100% by weight;
The nonwoven fabric according to aspect 7.
(Aspect 9)
The cushion material using the nonwoven fabric in any one of aspects 1-8.

  The non-woven fabric of the present invention has excellent elasticity, softness and bulk recovery, and can provide further excellent durability and a dull new unprecedented tactile sensation as needed. It can be placed under the top sheet in absorbent seats such as seats for automobiles, airplanes, railcars, ships, etc., general households, offices, sanitary napkins, disposable diapers, nursing care diapers, etc. Various cushioning materials used for second seats with high cushioning properties, women's bra pads, shoulder pads, elbow pads, knee pads, bed pads, bed mats, mattresses, futons and pillows In addition, it is bulky, elastic, and has excellent bulk recovery properties. It is suitable for constituting the timber, and the like.

1 First component of first (or second) three-dimensional crimped fiber 2 Second component of first (or second) three-dimensional crimped fiber 3 Second of first (or second) three-dimensional crimped fiber Center of gravity position in fiber cross section of component 4 Center of gravity position in fiber cross section of first (or second) three-dimensional crimped fiber 5 Radius in fiber cross section of first (or second) three-dimensional crimped fiber 10 First (or first) 2) Three-dimensional crimped fiber 11 First (or third) three-dimensional crimped fiber 12 Second three-dimensional crimped fiber expressing microcrimp 13 First (or third) three-dimensional crimped fiber and second Intersection of three-dimensional crimped fibers 14 Second solid-crimped fibers with thin, deformed, and cut fibers

Claims (9)

A nonwoven fabric comprising a first three-dimensional crimped fiber and a second three-dimensional crimped fiber,
The first three-dimensional crimped fiber is a fiber having a three-dimensional crimp,
The first three-dimensional crimped fiber is a composite fiber containing a first component and a second component,
The first component includes linear low density polyethylene (LLDPE) having a melting point of 130 ° C. or lower,
The second component includes polyester,
In the cross section of the composite fiber, the first component occupies at least 20% of the fiber surface;
The melting point of the second component is higher than the melting point of the first component,
The gravity center position of the second component is shifted from the gravity center position of the composite fiber,
The second three-dimensional crimped fiber is a fiber having a coiled micro crimp,
The number of crimps of the first three-dimensional crimped fiber is less than the number of crimps of the second three-dimensional crimped fiber,
At least a portion of a surface of the first solid crimped fibers, as thermal bonding component, have adhered to at least a portion between fibers,
The components constituting the second three-dimensional crimped fiber are not substantially melted,
Nonwoven fabric for cushion materials . The nonwoven fabric for cushion materials according to claim 1, wherein the first three-dimensional crimped fiber is an actual crimped fiber in which three-dimensional crimp is manifested. The nonwoven fabric for cushion material according to claim 1 or 2 , wherein the second three-dimensional crimped fiber is a latent crimped fiber, and a micro crimp is formed by the expression of the latent crimp. The second three-dimensional crimped fiber is a composite fiber containing a first component and a second component,
The first component includes a propylene copolymer having a melting point of 135 ° C. or higher,
The second component includes a thermoplastic resin having a melting point of 145 ° C. or higher,
In the cross section of the composite fiber, the first component occupies at least 20% of the fiber surface;
The melting point of the second component is higher than the melting point of the first component,
The gravity center position of the second component is shifted from the gravity center position of the composite fiber,
The nonwoven fabric for cushion materials according to claim 3 . When the lowest melting point resin melting point among the resin constituting the second three-dimensional crimped fibers and Tm _C, and Tm _C, the melting point of the thermal bonding component of the first three-dimensional crimped fibers and (Tm _B) The nonwoven fabric for cushion materials according to any one of claims 1 to 4 , wherein the temperature difference (Tm _C -Tm _B ) is 5 ° C or more.   In the first three-dimensional crimped fiber,
  The first component contains 75% by mass or more of the linear low density polyethylene (LLDPE) and the low density polyethylene (LDPE) as a polymer component,
  When the linear low density polyethylene and the low density polyethylene have a combined mass of 100% by mass, the linear low density polyethylene accounts for 95% to 75% by mass, Density polyethylene accounts for 5% to 25% by weight,
The nonwoven fabric for cushion materials in any one of Claims 1-5. Furthermore, the nonwoven fabric for cushion materials in any one of Claims 1-6 containing a 3rd three-dimensional crimped fiber.   The nonwoven fabric for cushion materials according to claim 7, wherein the third three-dimensional crimped fiber is an actual crimped fiber. Based on the total mass of the nonwoven fabric,
The content of the first three-dimensional crimped fiber is 20 % by mass to 80 % by mass,
The content of the second three-dimensional crimped fiber is 5 % by mass to 55% by mass,
The content of the third three-dimensional crimped fiber is 15% by mass to 75 % by mass,
The total content of the first, second and third three-dimensional crimped fibers does not exceed 100% by weight;
The nonwoven fabric for cushion materials according to claim 7 or 8 .