JP5436558B2 - Crimpable composite fiber, and fiber assembly and fiber product using the same - Google Patents

Description

  The present invention relates to a fiber aggregate mainly having high elasticity and bulk recovery, particularly to an actual crimpable conjugate fiber suitable for a nonwoven fabric, a latent crimpable conjugate fiber, and a fiber assembly and a fiber product using the same.

  Low melting point at least partially exposed on the fiber surface in various applications such as sanitary materials, packaging materials, non-woven fabrics used in wet tissues, filters, wipers, etc., non-woven fabrics used in hard cotton, chairs, etc., molded products A heat-bonding nonwoven fabric using a heat-fusible composite fiber composed of a component and a high-melting component having a melting point higher than that of the low-melting component is used. In particular, nonwoven fabrics that have excellent elasticity and bulk recovery properties, that is, bulk recovery properties in the thickness direction, are increasingly demanded as substitute materials for urethane foam. Various studies have been made on composite fibers suitable for excellent nonwoven fabrics. In addition, the composite fiber suitable for the nonwoven fabric used in the above-mentioned applications is excellent in elasticity and shape recovery of the fiber itself, so that the composite fiber itself can be used as stuffed cotton in various bedding and clothing items such as comforters and mattresses. It is being considered.

  Many studies have so far been made on such a heat-adhesive conjugate fiber that exhibits excellent bulk recovery when it is made into a fiber aggregate such as a non-woven fabric or a composite fiber excellent in elasticity of the fiber itself. . The following Patent Documents 1 and 2 propose a composite fiber composed of a polyester component having a melting point of 200 ° C. or higher and a polyether ester block copolymer component having a melting point of 180 ° C. or lower, that is, a so-called elastomer component. By using an elastomer component for the sheath component, when subjected to compressive deformation, the degree of freedom of the bonded portion and the durability are improved, so that a fiber having a high bulk recovery property is obtained.

  Patent Document 3 is composed of a first component containing a polytrimethylene terephthalate (PTT) polymer and a second component containing a polyolefin polymer, particularly polyethylene, and the center of gravity of the first component in the fiber cross section Proposed crimped conjugate fiber that has been crimped by shifting it from the center of gravity. By using a polymer having high bending elasticity and low bending hardness as the first component, and further including this manifest crimpable composite fiber having a fiber cross section as an eccentric shape and a crimped shape as a wave shape. A non-woven fabric having high recoverability, flexibility, and large initial bulk can be obtained.

  Patent Documents 4 to 5 show a crimpable conjugate fiber containing a sheath component containing polybutene-1 (hereinafter also referred to as PB-1), and excellent bulk recovery using the same and improved initial bulk recovery. Proposed non-woven fabric.

  In Patent Documents 1 and 2, a polyester ether elastomer is used as a sheath component, and this polymer has rubber-like elasticity, and a high degree of freedom for deformation of the bonding point is utilized. Trying to get. However, since this polyester ether elastomer is a copolymer of hard polyester and soft ether and contains a soft component with low heat resistance, it is easily softened by heat and the bulk of the nonwoven fabric is reduced during heat processing. Occurs. As a result, the composite fiber using the polyester ether elastomer as the sheath component has a problem that the initial volume when made into a non-woven fabric is small, only a high-density non-woven fabric is obtained, and the use is limited. In addition, the nonwoven fabric after being compressed in a heated state or after being repeatedly compressed is the original nonwoven fabric such that the bonding point between the fibers and the fibers themselves are broken, bent, fiber strength is reduced, etc. In comparison, there was a problem that the nonwoven fabric hardness was greatly reduced.

  In Patent Document 3, the polymer used for the core and the fiber cross section are specified, and the crimped state is specified so as to obtain a nonwoven fabric with high bulk recovery. Although the nonwoven fabric thickness (initial bulk) is large, there is a problem that the bulk recovery property, particularly the initial bulk recovery property immediately after dewetting is not sufficient, and the application is limited.

  Moreover, the composite fibers proposed in Patent Documents 4 to 5 are obtained by processing a fiber web using the composite fibers into a nonwoven fabric in which constituent fibers are thermally bonded by thermal processing, or obtained nonwoven fabrics. When heat-bonding and bonding, the so-called sheath component occupying most of the fiber surface is composed of polybutene-1 and polypropylene having a higher melting point than polybutene-1, so that the apparent melting point of the sheath component is increased. In the heat treatment at low temperature, there is a problem that the thermal adhesiveness and the strength of the nonwoven fabric after the thermal bonding are not sufficient, and the temperature condition of the thermal bonding process is difficult.

  In addition to Patent Documents 1 to 5, various studies have been made on non-woven fabrics excellent in bulk recoverability, composite fibers suitable for non-woven fabrics excellent in bulk recoverability, and non-woven fabrics using the same. Decrease in recoverability is observed, and there is a problem that fibers and non-woven fabrics suitable for applications requiring high bulk recoverability even after repeated compression, such as cushioning materials, are not obtained.

JP-A-4-240219 JP-A-5-247724 JP 2003-3334 A JP 2007-126806 A JP 2008-248421 A

  In order to solve the above-described conventional problems, the present invention has high elasticity, bulk recovery, durability when repeatedly compressed, and high elasticity, bulk recovery, durability when used at high temperatures. A crimpable conjugate fiber, and a fiber assembly and a fiber product using the same are provided.

  The crimpable conjugate fiber of the present invention is a conjugate fiber comprising a first component and a second component, wherein the first component comprises polybutene-1 and linear low-density polyethylene, The content of the linear low density polyethylene in the component is 2 to 25% by mass, and the second component is a polymer having a melting peak temperature that is 20 ° C. or more higher than the melting peak temperature of polybutene-1, or a melting start temperature. Includes a polymer having a temperature of 120 ° C. or higher, and when viewed from the fiber cross section, the first component occupies at least 20% of the surface of the composite fiber, and the center of gravity of the second component deviates from the center of gravity of the composite fiber. The composite fiber is characterized in that it is a manifested crimp that exhibits a three-dimensional crimp or a latent crimp that exhibits a three-dimensional crimp when heated. In the present invention, the melting start temperature means an extrapolated melting start temperature measured by a differential scanning calorimetry (DSC) measurement method defined in JIS-K-7121. Moreover, in this invention, a melting peak temperature means the melting peak temperature calculated | required from the DSC curve measured according to JIS-K-7121.

  The fiber assembly of the present invention contains 30% by mass or more of crimped conjugate fiber, and the crimped conjugate fiber is a conjugate fiber containing a first component and a second component, wherein the first component is Polybutene-1 and linear low density polyethylene are included, the content of linear low density polyethylene in the first component is 2 to 25% by mass, and the second component is a melt of polybutene-1. Including a polymer having a melting peak temperature 20 ° C. higher than the peak temperature or a polymer having a melting start temperature of 120 ° C. or more, and the first component occupies at least 20% of the surface of the composite fiber when viewed from a fiber cross section The centroid position of the second component is shifted from the centroid position of the composite fiber, and the composite fiber is an actual crimp that exhibits a three-dimensional crimp, or a latent crimp that develops a three-dimensional crimp when heated. Specially To.

  The textile product of the present invention has at least a part of the fiber assembly of the present invention, and includes hard cotton, bedding, a vehicle seat, a chair, a shoulder pad, a bra pad, clothing, a hygiene material, a packaging material, a wet tissue, and a filter. It is characterized by being formed into a sponge-like porous wiping material, a sheet-like wiping material or padding cotton.

  The crimped conjugate fiber of the present invention contains polybutene-1 and linear low-density polyethylene as the first component, and has a melting peak temperature that is 20 ° C. higher than the melting peak temperature of the polybutene-1 as the second component. By including a polymer or a polymer having a melting start temperature of 120 ° C. or higher, a fiber excellent in spinnability, stretchability, crimp development, and the like is obtained. And, by using the crimpable conjugate fiber of the present invention, a composite fiber excellent in heat processability, which has excellent bulk recovery properties, and can be strongly thermally bonded to each other even in heat bonding processing at low temperature, and this A fiber assembly and a fiber product using can be obtained.

  The nonwoven fabric using the crimped conjugate fiber of the present invention is excellent in both initial bulk and bulk recoverability, such as hard cotton such as cushioning materials, hygiene materials, packaging materials, filters, cosmetic materials, and female bras. It can be suitably used for low-density nonwoven fabric products such as pads and shoulder pads. In addition, the crimped conjugate fiber of the present invention can be suitably used as stuffed cotton used for various beddings such as mattresses and comforters and various clothing items, utilizing the appropriate elasticity and resilience of the fiber itself.

FIG. 1 shows a fiber cross section of a crimped conjugate fiber according to an embodiment of the present invention. 2A to 2C show crimped forms of the crimped conjugate fiber according to one embodiment of the present invention. FIG. 3 shows a form of conventional mechanical crimping. FIG. 4 shows a crimped form in which wavy crimps and serrated crimps are mixed in the crimped conjugate fiber of the present invention.

  The crimped conjugate fiber of the present invention has high elasticity, bulk recovery, and durability when repeatedly compressed, and also has high elasticity, bulk recovery, and durability when used at high temperatures. In particular, the fiber aggregate using the crimped conjugate fiber having an actual crimp of the present invention (hereinafter also referred to as an actual crimped conjugate fiber) has an initial bulkiness. In addition, the fiber assembly using the crimped conjugate fiber having latent crimp of the present invention (hereinafter also referred to as latent crimped conjugate fiber) has a latent crimp when it is heat-molded by stacking a plurality of layers. As a result, the interlaced fiber between layers is improved and the elasticity and bulk recovery are further enhanced.

(First ingredient)
In the crimped conjugate fiber of the present invention, the first component contains polybutene-1 and linear low density polyethylene. Moreover, the crimpable composite in which the flexibility and shape maintaining property (return to deformation) of polybutene-1 is utilized by arranging the first component so as to occupy at least 20% of the surface of the composite fiber. Fiber is obtained.

  In addition, in the present invention, the first component contains linear low density polyethylene in addition to polybutene-1, so that spinnability such as uniform fiber formation and stretchability during melt spinning, and defibration of raw cotton And the raw cotton crimp expression was found to be improved. That is, when melt spinning is performed only with polybutene-1, the viscosity of the nozzle discharge polymer is difficult to stabilize and uniform fibers are difficult to obtain, and polybutene-1 has a high molecular weight and is free of molecular chains. However, it is difficult to perform the stretching process because it is scarce, and in addition, because the heat shrinkability is very large, the fiber shrinks during heat processing, and it is said that it is difficult to obtain a nonwoven fabric with good formation, When the first component contains linear low-density polyethylene in addition to polybutene-1, problems such as poor spinnability and difficult stretchability of the polybutene-1 can be solved. Polybutene-1 has a high molecular weight, that is, the molecular chain constituting the polybutene-1 is long and the entanglement between the molecules is large, which is considered to cause the above-described problem of difficulty in stretching. Here, as in the present invention, when the polymer component contains linear low density polyethylene in addition to polybutene-1, the linear low density polyethylene enters between the molecular chains of the high molecular weight polybutene-1, and polybutene- Since the entanglement of the molecular chains of 1 is moderately suppressed, it is estimated that the stretchability is improved. In addition, the fiber assembly using the crimped conjugate fiber obtained by using a polymer containing linear low-density polyethylene as the first component occupying most of the surface portion of the crimped conjugate fiber is as described above. Excellent heat workability (heat treatment in a shorter time, heat adhesion between uniform constituent fibers) is exhibited by the linear low density polyethylene contained in the first component of the crimped conjugate fiber. That is, the first component occupying most of the fiber surface of the crimped conjugate fiber is composed of polybutene-1 as a main component and 2 to 25% by mass of linear low-density polyethylene added to the first component. Thus, there is a phenomenon in which the apparent melting peak temperature of the first component is increased by the addition of a high melting point polymer, which can occur when a polymer (for example, polypropylene) having a melting point higher than that of polybutene-1 is added to polybutene-1. No longer occurs. As a result, the crimpable conjugate fiber of the present invention can be thermally bonded with sufficient adhesive strength even by thermal processing at a lower temperature and in a shorter time, and the post-processing of the fiber assembly including the crimped conjugate fiber. Increases sex. Further, since the linear low density polyethylene is excellent in impact resistance, the fiber assembly of the present invention in which the constituent fibers are thermally bonded by the first component containing the linear low density polyethylene in the crimped conjugate fiber of the present invention. Even if the product is used for applications in which repeated load is applied, the adhesion point between the fibers does not come off and peeling does not easily occur, and the product has excellent resistance to repeated compressive residual strain and compressive residual strain.

  The linear low-density polyethylene is not particularly limited, and for example, a copolymer with an α-olefin polymerized using a Ziegler catalyst or a metallocene catalyst can be used. From the viewpoint that the molecular weight range is narrow and the branches are uniformly distributed, it is preferable to use a copolymer with an α-olefin polymerized using a metallocene catalyst. Linear low-density polyethylene polymerized using a metallocene-based catalyst is characterized by a uniform molecular weight, composition, and crystallinity distribution. From the above characteristics, linear low density polyethylene polymerized using a metallocene-based catalyst can easily be uniformly dispersed inside PB-1 even when added in an amount of 2 to 25% by mass. It is presumed to be effective for improving stretchability. Although it does not specifically limit as said alpha olefin, For example, 1-butene, 1-hexene, 1-octene, 1-pentene, 3,3-dimethyl-1-butene, 4-methyl-1-pentene, 4,4 -Dimethyl-1-pentene, 1-decene, 1-dodecene, 1-tetradecene, 1-octadecene and the like. As a copolymer with α-olefin polymerized using the metallocene catalyst, for example, “Harmolex” (registered trademark) NJ744N manufactured by Nippon Polyethylene Co., Ltd., “Kernel” (registered trademark) KS560T and KC571, manufactured by Ube Maruzen Polyethylene Co., Ltd. Commercially available products such as 420SD may be used.

  The linear low-density polyethylene in the first component preferably has a ratio (Q value) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) of 6 or less. A more preferable Q value is 2 to 5, and a particularly preferable Q value is 2.2 to 3.5. In addition to polybutene-1, the first component contains linear low density polyethylene, preferably linear low density polyethylene polymerized using a metallocene catalyst, which satisfies the above Q value range. In the crimped conjugate fiber of the present invention containing polybutene-1, stretchability is improved. In addition, since the first component occupying most of the fiber surface contains linear low-density polyethylene, a slip effect is exerted on the fiber surface. It is preferable because the defibration of the raw cotton after cutting into raw cotton (staple fiber) is improved.

Further, from the viewpoint of good compatibility with PB-1, the density of the linear low-density polyethylene measured according to JIS-K-7112 is preferably 0.930 g / cm ³ or less. more preferably 920 g / cm ³ or less, particularly preferably 0.915 g / cm ³ or less. If it is in said range, compatibility with PB-1 is also favorable and heat resistance is also high. The lower limit of the density of the linear low-density polyethylene is not particularly limited, but is preferably 0.870 g / cm ³ or more, more preferably 0.880 g / cm ³ or more, and particularly preferably 0.8. It is 890 g / cm ³ or more. When the density of the linear low-density polyethylene is less than 0.870 g / cm ³ , the heat resistance of the first component constituting the crimped conjugate fiber is likely to be lowered, for example, at a temperature higher than room temperature in the range of 40 to 80 ° C. There is a risk that the bulk recovery property and the compressive residual strain resistance of the material will be reduced.

  Moreover, the viewpoint that the compatibility with PB-1, the elasticity of the fiber obtained, the bulk recovery property of the fiber assembly produced using the obtained crimped conjugate fiber, and the compression residual strain resistance are good From the above, the flexural modulus measured according to JIS-K-7171 of the linear low density polyethylene is preferably 800 MPa or less, more preferably 20 to 650 MPa, and particularly preferably 25 to 300 MPa. Most preferably, it is 30 to 180 MPa. If it is in said range, compatibility with PB-1 is also favorable, heat resistance is also high, and the obtained fiber aggregate will be excellent in bulk recovery property and compression residual strain resistance. When the flexural modulus of the linear low density polyethylene is increased, the flexibility of the polymer is lost, and the elasticity of the resulting crimped conjugate fiber tends to be reduced. When it exceeds 800 MPa, there is a fear that the bulk recovery property and resistance to compressive residual strain of the fiber aggregate produced using the crimped conjugate fiber obtained will be lowered. Further, when the bending elastic modulus of the linear low density polyethylene is increased, the melting peak temperature of the polymer tends to be lowered. When the bending elastic modulus of the linear low density polyethylene is lower than 20 MPa, the heat resistance is decreased. , The bulk recovery property at high temperature of the obtained fiber aggregate may be lowered.

  The linear low density polyethylene preferably has a melting peak temperature of 70 to 130 ° C. determined from a DSC curve measured according to JIS-K-7121. More preferably, it is 80-125 degreeC, More preferably, it is 90-123 degreeC. When the melting peak temperature is 70 to 130 ° C., the heat resistance is high, and the bulk recovery property at high temperature is good. In the present invention, the melting peak temperature means a melting peak temperature obtained from a DSC curve measured according to JIS-K-7121. In the present invention, the melting peak temperature obtained from the DSC curve is also referred to as the melting point.

  The linear low-density polyethylene is a melt flow rate measured at 190 ° C. according to JIS-K-7210 (MFR; measurement temperature 190 ° C., load 2.16 kgf (21.18 N). Is preferably 1 to 30 g / 10 min. A more preferred MFR 190 is 3-25 g / 10 min, even more preferably 5-20 g / 10 min. When the MFR 190 is 1 to 30 g / 10 min, the heat resistance is good, the bulk recovery property at high temperatures is high, and the take-up property and stretchability are good.

  Polybutene-1 used in the present invention preferably has a melting peak temperature of 115 to 130 ° C. determined from a DSC curve measured according to JIS-K-7121. More preferably, it is 120-130 degreeC. When the melting peak temperature is 115 to 130 ° C., the heat resistance is high, and the bulk recovery property at high temperature is good.

  The polybutene-1 has a melt flow rate (MFR; measurement temperature 190 ° C., load 2.16 kgf (21.18 N), hereinafter referred to as MFR190) measured in accordance with JIS-K-7210 1-30 g. / 10 minutes is preferable. A more preferred MFR 190 is 3-25 g / 10 min, even more preferably 3-20 g / 10 min. When MFR190 is 1 to 30 g / 10 min, polybutene-1 has a high molecular weight, and therefore, heat resistance is good, and bulk recovery when heated is high, which is preferable. Further, the take-up property of spinning and the stretchability are improved.

  In the first component, polypten-1 is a main component and is contained in an amount of 70% by mass or more based on the entire first component. From the viewpoint of good productivity, cushioning properties, and good bulk recovery at high temperatures, it is preferably contained in an amount of 75 to 98% by mass, more preferably 80 to 97% by mass, and more preferably 85 to 97% by mass. It is particularly preferred that it is contained, and it is most preferred that it is contained in an amount of 87 to 96% by mass.

  As described above, polybutene-1 is spun when the compatibilizing effect on polybutene-1 is too low by blending linear low-density polyethylene exhibiting an appropriate compatibilizing effect with polybutene-1. Since the properties and stretchability are not improved, the problem that it is difficult to obtain a uniform composite fiber can be solved.

  In the first component, the amount of the linear low-density polyethylene added is 2 to 25% by mass, more preferably 3 to 20% by mass when the entire first component is 100% by mass. It is particularly preferably 15 to 15% by mass, and most preferably 4 to 12%. Within the above range, the flow characteristics of PB-1 can be improved, stable and uniform spinning can be achieved, and stretchability can be improved.

  The first component contains polybutene-1 and linear low-density polyethylene as described above, and further contains an ethylene-ethylenically unsaturated carboxylic acid copolymer within the range not impairing the effects of the present invention. Good. Since the ethylene-ethylenically unsaturated carboxylic acid copolymer is compatible with polybutene-1 as in the case of the linear low density polyethylene, the first component is an ethylene-ethylenically unsaturated carboxylic acid copolymer. Further, by including it, spinnability such as uniform fiber formation and stretchability during melt spinning can be improved. In addition to the polybutene-1 and the linear low density polyethylene, the crimpable conjugate fiber containing the ethylene-ethylenically unsaturated carboxylic acid copolymer is added to the fiber web or nonwoven fabric containing the fiber. On the other hand, when heat processing such as heat bonding, even if heat processing is performed at a high temperature for a long time, the sheath component is thinned and heat bonded at the point where the constituent fibers are heat bonded (hereinafter also referred to as heat bonding points). Since the phenomenon of so-called “adhesion point thinning” (hereinafter, simply referred to as “adhesion point thinning”) does not easily occur, it becomes possible to firmly heat-bond the constituent fibers together, and heat with higher adhesive strength. An adhesive nonwoven fabric can be obtained.

  Although it does not specifically limit as ethylenically unsaturated carboxylic acid which comprises the ethylene-ethylenically unsaturated carboxylic acid copolymer used for the crimpable conjugate fiber of this invention, For example, acrylic acid, methacrylic acid, ethacrylic acid, Examples thereof include fumaric acid, maleic acid, itaconic acid, monomethyl maleate, monoethyl maleate, maleic anhydride, itaconic anhydride and the like.

  Specific examples of the ethylene-ethylenically unsaturated carboxylic acid copolymer include an ethylene-acrylic acid copolymer (EAA), an ethylene-methacrylic acid copolymer (EMAA), an ethylene-ethacrylic acid copolymer, and ethylene. -A maleic acid copolymer, an ethylene- fumaric acid copolymer, an ethylene- itaconic acid copolymer, an ethylene- maleic anhydride copolymer, an ethylene- itaconic anhydride copolymer, etc. are mentioned. Among these, an ethylene-acrylic acid copolymer, an ethylene-methacrylic acid copolymer, and an ethylene-maleic acid copolymer are preferable, and an ethylene-acrylic acid copolymer and an ethylene-methacrylic acid copolymer are more preferable.

  The ethylene-ethylenically unsaturated carboxylic acid copolymer is not limited to a copolymer composed of ethylene and an ethylenically unsaturated carboxylic acid, but includes, for example, two or more types of components containing ethylenically unsaturated carboxylic acid in ethylene. It may be a copolymer in which other components are copolymerized, including a copolymerized terpolymer (terpolymer).

  Examples of the monomer used as the other copolymerization component include vinyl esters such as vinyl acetate and vinyl propionate, methyl acrylate, ethyl acrylate, isopropyl acrylate, nbutyl acrylate, isobutyl acrylate, and acrylic acid. Ethylenic unsaturated carboxylic acid esters such as acrylic acid esters such as isooctyl, methacrylic acid esters such as methyl methacrylate and isobutyl methacrylate, maleic acid esters such as dimethyl maleate and diethyl maleate, carbon monoxide, sulfur dioxide, etc. Is mentioned.

  The copolymer in which ethylene, ethylenically unsaturated carboxylic acid and any other copolymerization component are copolymerized is not particularly limited. For example, ethylene, maleic anhydride, and an acrylic ester are copolymerized. An ethylene-acrylate-maleic acid polymer ("Bondyne" (registered trademark) manufactured by Arkema Japan) and the like can be mentioned.

  The ethylenically unsaturated carboxylic acid content in the ethylene-ethylenically unsaturated carboxylic acid copolymer is 1 to 50% by mass, preferably 1 to 29% by mass. In particular, in the case of acrylic acid, it is preferably 5 to 25% by mass, and in the case of methacrylic acid, it is preferably 5 to 20% by mass. Moreover, content of the other copolymerization component in the said ethylene-ethylenically unsaturated carboxylic acid copolymer is 0-30 mass%, Preferably it is the range of 0-20 mass%.

  In the present invention, as the ethylene-ethylenically unsaturated carboxylic acid copolymer, in addition to the ethylene-ethylenically unsaturated carboxylic acid copolymer itself, an ionomer in which a part or all of the carboxyl group is converted into a metal salt. Can be used. Examples of the metal species constituting the ionomer include monovalent metals such as lithium, sodium, and potassium, and polyvalent metals such as magnesium, calcium, zinc, copper, cobalt, manganese, lead, and iron. Or zinc is preferable.

  Moreover, in this invention, said ethylene-ethylenically unsaturated carboxylic acid copolymer may be used independently, and may be used in combination of 2 or more type.

  Although the said ethylene-ethylenically unsaturated carboxylic acid copolymer is not specifically limited, For example, it can obtain by high pressure radical copolymerization. The ethylene-ethylenically unsaturated carboxylic acid copolymer ionomer can be obtained by ionizing the ethylene-ethylenically unsaturated carboxylic acid copolymer by a conventional method.

  As described above, when the first component in the crimped conjugate fiber of the present invention contains an ethylene-ethylenically unsaturated carboxylic acid copolymer that exhibits an appropriate compatibilizing effect with respect to polybutene-1, polybutene- It is possible to solve the problem that it is difficult to obtain a uniform composite fiber caused by the low spinnability of polybutene-1, which occurs when the effect of compatibilization to 1 is too low. Moreover, although the composite fiber which consists of the 1st component mainly containing polybutene-1 produced when the compatibilizing effect to polybutene-1 is too high is obtained, when producing a thermobonding nonwoven fabric from the obtained composite fiber, It is possible to solve the problem that adhesion points and thinness are generated by heat processing. That is, by blending an ethylene-ethylenically unsaturated carboxylic acid copolymer exhibiting an appropriate compatibilizing effect with polybutene-1, it becomes possible to obtain uniform composite fibers containing them, and The heat-bonding property of the obtained composite fiber is improved, and the adhesion point and thinning that may occur when heat-processed and bonded at a temperature higher than the melting point of polybutene-1 can be eliminated.

  In the first component, when an ethylene-ethylenically unsaturated carboxylic acid copolymer is added, the addition amount may be 0.5 to 20% by mass when the entire first component is 100% by mass. The amount is preferably 1 to 15% by mass, more preferably 3 to 10% by mass, and particularly preferably 4 to 9% by mass. If it is 0.5% by mass or more, a crimped conjugate fiber excellent in thermal adhesiveness can be obtained, and the adhesive strength between the fibers does not decrease even at a high temperature, for example, a temperature of 190 ° C. or higher. There are no adhesion points or skinnyness. Moreover, by being 20 mass% or less, fiber structures, such as a nonwoven fabric, with favorable hardness retainability (bulk recovery property) are obtained.

  The ethylene-ethylenically unsaturated carboxylic acid copolymer preferably has an MFR190 of 3 to 60 g / 10 min measured according to JIS-K-7210. A more preferred MFR 190 is 5 to 40 g / 10 min, even more preferably 5 to 30 g / 10 min. When MFR190 is 60 g / 10 or less, the effect which suppresses the adhesive point thinning which may arise when heat-processing to the fiber web containing the obtained crimpable conjugate fiber can be improved. Moreover, when MFR190 is 3 g / 10min or more, it is excellent in the operativity in a spinning process and a drawing process, and it becomes easy to obtain a uniform crimpable conjugate fiber.

  The ethylene-ethylenically unsaturated carboxylic acid copolymer preferably has a melting peak temperature determined from a DSC curve measured according to JIS-K-7121 of 60 ° C or higher, preferably 70 ° C or higher. Is more preferable, and it is still more preferable that it is 70-120 degreeC. When the melting peak temperature is 60 ° C. or higher, the effect of suppressing the adhesion point thinness is high, and it is difficult for the cushion performance to be reduced such as a decrease in bulk recovery property and an increase in compressive strain rate due to thermal processing. Moreover, when the melting peak temperature is 70 to 120 ° C., the effect of suppressing the adhesion point and the thinness, the effect of suppressing the deterioration of the cushioning performance, and the like can be exhibited better.

  The ethylene-ethylenically unsaturated carboxylic acid copolymer preferably has a softening temperature (Vicat softening point) measured according to JIS-K-7206 of 40 ° C or higher, more preferably 50 ° C or higher. Yes, particularly preferably 50 to 100 ° C. When the softening temperature is 40 ° C. or higher, the effect of suppressing the adhesive point thinness is high, and the cushioning performance such as the decrease in bulk recovery property and the increase in the compressive strain rate due to thermal processing is less likely to occur. When the softening temperature is 50 to 100 ° C., the effect of suppressing the adhesion point thinness and the effect of suppressing the deterioration of the cushion performance can be exhibited better.

  The polymer that can be further blended with the first component has a polar group such as a vinyl group, a carboxyl group, and maleic anhydride in addition to the polyolefin-based polymer other than the above-mentioned polyolefin-based polymer as long as the effects of the present invention are not impaired. Examples thereof include copolymer polymers with olefins, and various thermoplastic elastomers such as polyolefins, styrenes, and polyesters.

  In addition, various known additives may be added to the first component as long as they do not impair the effects of the present invention and do not affect fiber productivity, nonwoven fabric productivity, thermal adhesiveness, and touch. Is possible. Examples of the first component include other polymers, known crystal nucleating agents such as organic substances or inorganic substances (for example, calcium carbonate, talc, etc.), antistatic agents, pigments, matting agents, heat stabilizers, and light stabilizers. In addition, flame retardants (for example, inorganic compounds such as halogen-based, phosphorus-based, non-halogen-based, antimony trioxide, and the like), antibacterial agents, lubricants, plasticizers, softeners, and the like can be mixed depending on applications. When a crystal nucleating agent is added as the additive, the effect of preventing inter-fiber fusion during spinning can be further improved, and a non-woven fabric having a soft touch can be obtained. The addition amount of the crystal nucleating agent is not particularly limited, but considering the productivity of the fiber, it is preferably added at a rate of 20% by mass or less, and added at a rate of 10% by mass or less with respect to the total mass of the first component. More preferably.

  The first component constituting the crimped conjugate fiber of the present invention has the above-described characteristics, that is, contains 70% by mass or more, preferably 75% by mass or more of PB-1 as a main component of the first component, It contains 2 to 25% by mass of density polyethylene. As a result, the melting point of the first component after spinning becomes a low temperature, and the phenomenon that the apparent melting point of the first component rises, which can occur when polypropylene is added to PB-1 instead of linear low-density polyethylene, is less likely to occur. . This is because the crimped conjugate fiber obtained is measured using a differential scanning calorimeter (DSC), and the melting point of each component after spinning is determined from the heat of fusion curve obtained from this measurement. I can confirm. That is, the crimped conjugate fiber of the present invention has a melting point (Tf1) of the first component after spinning determined from a DSC curve measured according to JIS-K-7121 of 140 ° C. or less, preferably 90 to 135 ° C., More preferably, it is 100-130 degreeC, Most preferably, it is 115-130 degreeC, Most preferably, it is 120 to 125 degreeC. When the melting point (Tf1) of the first component after spinning is within this range, when producing a fiber assembly such as a nonwoven fabric by heat bonding, sufficient adhesive strength can be obtained at a lower temperature in a shorter time. A heat-adhesive fiber assembly having a thermal adhesive property can be obtained. The higher the melting point of the first component after spinning, the more difficult it is to obtain the above effect. The polyolefin polymer (the melting point (Tf1) of the first component after spinning exceeds 140 ° C. or the melting peak temperature is high). For example, the first component has a so-called double peak in which a plurality of melting point peaks caused by the first component appear at a temperature lower than the melting point (Tf2) after spinning of the second component, which occurs when polypropylene is added. If this is the case, there is a fear that a fiber aggregate having a low adhesive strength at a low temperature and having sufficient adhesive strength cannot be obtained. The lower limit of the melting point (Tf1) of the first component after spinning is not particularly limited, but if it is lower than 90 ° C., the heat resistance and the bulk recovery property at high temperatures may be lowered. In addition, as described above, in the crimped conjugate fiber of the present invention, the melting point of the first component of the composite fiber after spinning has a plurality of peaks due to the first component in the heat of fusion curve, so-called double peak. If the shape is not preferable when performing heat bonding processing, it is easy to overlap with the melting point after spinning of PB-1, which is the main component of the first component, and the peak due to the first component is present in the heat of fusion curve. A linear low density polyethylene having a single so-called single peak is preferred.

(Second component)
The second component of the crimped conjugate fiber of the present invention may be a polymer having a melting peak temperature 20 ° C. or higher than the melting peak temperature of polybutene-1 or a polymer having a melting start temperature of 120 ° C. or higher. Although not particularly limited, polymers having excellent bending strength and bending elasticity are preferable. For example, polyester polymers such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, nylon 6, nylon 66, nylon 11, polyamides such as nylon 12, polyolefin polymers such as polypropylene and polymethylpentene, polycarbonate, polystyrene and the like. When using said polymer as a 2nd component, a polymer may be used independently and may be used in combination of 2 or more type. In the crimped conjugate fiber of the present invention, the polymer used for the second component is preferably a polyester polymer or a polyolefin polymer. By using a polyolefin-based polymer as the second component and using the polyolefin-based polymer together with the first component as described above, the crimped conjugate fiber of the present invention can be easily recycled. Further, the crimpable conjugate fiber of the present invention using the polyester-based polymer as the second component is composed of the second component constituting the vicinity of the center of the conjugate fiber and the melting point of the first component occupying most of the fiber surface. Because the difference becomes large, the second component maintains its shape even when the composite fiber, fiber web, and nonwoven fabric are heat bonded at the temperature at which the first component is sufficiently heat bonded, so that sag due to thermal processing is unlikely to occur. In addition, it is easy to control the processing temperature in the heat processing step, and it is easy to obtain a fiber assembly having high adhesive strength.

  First, in the crimped conjugate fiber of the present invention, a conjugate fiber using a polyester polymer as the polymer constituting the second component will be described. When a polyester polymer is used as the second component of the crimped conjugate fiber of the present invention, a polyester polymer having a melting peak temperature that is 20 ° C. or more higher than the melting peak temperature of polybutene-1, or a melting start temperature of 120 ° C. or more. The polyester polymer is not particularly limited, but a polymer excellent in bending strength and flexural elasticity is preferable. Therefore, polyethylene terephthalate (hereinafter also referred to as PET) and polytrimethylene terephthalate (hereinafter also referred to as PTT). And polybutylene terephthalate (hereinafter also referred to as PBT), more preferably polyethylene terephthalate or polytrimethylene terephthalate. When a polyester polymer is used as the second component in the crimped conjugate fiber of the present invention because it is easy to select and obtain a polymer having physical properties suitable for the use of the fiber, and the bulk recovery of the fiber is high. It is most preferable to use polyethylene terephthalate.

  The intrinsic viscosity [η] of the polyester polymer is preferably 0.4 to 1.2. More preferably, it is 0.5 to 1.1. When the intrinsic viscosity is less than 0.4, the molecular weight of the polymer is too low, so that not only the spinnability is inferior, but also the fiber strength is low and the practicality is poor. If the intrinsic viscosity exceeds 1.2, the molecular weight of the polymer becomes large and the melt viscosity becomes too high, so that single yarn breakage or the like occurs and it becomes difficult to perform good spinning. Further, by setting the intrinsic viscosity [η] within the above range, a composite fiber having excellent productivity and excellent bulk elasticity can be obtained. The intrinsic viscosity [η] referred to here is a value obtained by measuring with an Ostwald viscometer as an o-chlorophenol solution at 35 ° C., based on the following formula 1.

[Equation 1]

  However, in the above formula 1, ηr is a value obtained by dividing the viscosity at 35 ° C. in a diluted solution of a sample dissolved in o-chlorophenol having a purity of 98% or more by the concentration of the whole solvent measured at the same temperature, and C Is the solute weight value in grams per 100 ml of the solution.

  It is preferable that the melting peak temperature calculated | required from the DSC curve measured according to JIS-K-7121 of the said polyester is 180 to 300 degreeC. More preferably, it is 200 degreeC-270 degreeC. When the melting peak temperature is 180 to 300 ° C., the weather resistance is high, and the flexural modulus of the resulting composite fiber can be increased.

  Next, in the crimped conjugate fiber of the present invention, a conjugate fiber using a polyolefin polymer as a polymer constituting the second component will be described. When a polyolefin-based polymer is used as the second component of the crimped conjugate fiber of the present invention, a polyolefin-based polymer having a melting peak temperature that is 20 ° C. or more higher than the melting peak temperature of polybutene-1, or a melting start temperature of 120 ° C. or more. The polyolefin polymer is not particularly limited, but is preferably a polypropylene (hereinafter also referred to as PP) because a polymer excellent in bending strength and bending elasticity is preferable. The polypropylene is not particularly limited, and for example, a homopolymer, a random copolymer, a block copolymer, or a mixture thereof, as long as the properties necessary for a nonwoven fabric and a cushion material such as heat resistance and bulk recovery property are not impaired. If there is, it is possible to use polypropylene in which an elastomer component such as synthetic rubber is dispersed or mixed in polypropylene, but considering heat shrinkability, it is a homopolymer (homopolypropylene) or a block copolymer. It is preferable. In particular, homopolypropylene is advantageous in terms of bulk recovery and is preferable. Examples of the random copolymer and block copolymer include a copolymer of propylene and at least one α-olefin selected from the group consisting of ethylene and an α-olefin having 4 or more carbon atoms. The α-olefin having 4 or more carbon atoms is not particularly limited, but examples thereof include 1-butene, 1-pentene, 3,3-dimethyl-1-butene, 4-methyl-1-pentene, and 4,4-dimethyl. Examples include -1-pentene, 1-decene, 1-dodecene, 1-tetradecene, and 1-octadecene. Among these, from the viewpoint of bulk recoverability, it is preferably a kind selected from the group consisting of a propylene homopolymer, an ethylene-propylene copolymer, and an ethylene-butene-1-propylene terpolymer, and the resulting crimp In view of the heat resistance, recyclability after use and economical efficiency (manufacturing cost), the polyolefin polymer is particularly preferably homopolypropylene when the polyolefin polymer is used as the second component. Further, from the viewpoint of bulk recovery, when a mixture of polypropylene homopolymer, random copolymer, and block copolymer is used, the content of homopolypropylene is 73 to 100, assuming that the entire second component is 100% by mass. It is mass%, it is more preferable that it is 75-100 mass%, and it is especially preferable that it is 85-100 mass%.

  When polypropylene is used as the second component, the polypropylene has a melt flow rate (MFR) measured according to JIS-K-7210 (measurement temperature 230 ° C., load 2.16 kgf (21.18 N)), and MFR230 in the following. Is preferably 3 to 40 g / 10 min. A more preferred MFR 230 is 5 to 35 g / 10 min. When the MFR230 is 3 to 40 g / 10 min, the heat resistance is good, the bulk recovery property at a high temperature is high, and the take-up property and the drawability are good.

  When polypropylene is used for the second component, the ratio (Q value) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polypropylene is preferably 2 or more. A more preferable Q value is 3 to 12. The ratio (Q value) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polypropylene in the second component is more preferable depending on the type of steric crimps that the resulting crimped conjugate fiber exhibits. A value can be selected. For example, when trying to obtain an actual crimpable conjugate fiber in which steric crimp is manifested in the crimpable conjugate fiber, the Q value of polypropylene in the second component is preferably 4-12. It is more preferable that it is -9. In the case of obtaining a latent crimpable conjugate fiber that expresses steric crimps by heating, the Q value is preferably 3 to 5.

  When a polyolefin-based polymer such as polypropylene is used as the second component, it may further contain a thermoplastic elastomer in addition to the polyolefin-based polymer having a melting peak temperature higher by 20 ° C. or more than the melting peak temperature of the polybutene-1. In other words, it has excellent bulk recovery such as cushioning materials and clothing pads, as well as constituent fibers of fiber assemblies suitable for applications that require strain resistance against repeated loading, and the elasticity, shape recovery, and lightness of the fibers themselves. For crimped conjugate fibers used as stuffed cotton in various bedding and clothing items such as comforters and mattresses, the hardness, bulk recovery and resistance of the crimped conjugate fibers themselves and the fiber aggregates containing crimped conjugate fibers are resistant. It is preferable that a thermoplastic elastomer is contained in the second component that contributes to the strainability, in other words, the component existing inside more in the core-sheath type composite fiber (also called the core component in the core-sheath type composite fiber including the eccentric type). . Known thermoplastic elastomers can be used, and styrene elastomers, olefin elastomers, ester elastomers, amide elastomers, urethane elastomers, and vinyl chloride elastomers can be used. Among these, in the crimped conjugate fiber of the present invention, when a polyolefin polymer is used as the second component, it is 20 ° C. higher than the melting peak temperature of the polybutene-1 in consideration of recyclability after use. Preferably, the polyolefin polymer having a melting peak temperature is a polypropylene homopolymer, random copolymer, block copolymer, or a mixture thereof, and an olefin thermoplastic elastomer is used as the thermoplastic elastomer. Olefin-based thermoplastic elastomers include polyolefin resins such as polyethylene and polypropylene as hard segments, and ethylene-propylene rubbers such as ethylene-propylene rubber (EPM), ethylene-butene rubber (EBM), and ethylene-propylene-diene rubber (EPDM). Olefin-based thermoplastic elastomers that are commercially available are, for example, “Milastomer” (registered trademark) and “Notio” (registered trademark) manufactured by Mitsui Chemicals, Sumitomo Chemical Co., Ltd. “Esporex” (registered trademark), “Thermo Run” (registered trademark), “Zeras” (registered trademark), etc. manufactured by Mitsubishi Chemical Corporation can be used. In the crimped conjugate fiber of the present invention, when the second component constituting the crimped conjugate fiber is a polyolefin polymer, an appropriate amount of a thermoplastic elastomer such as an olefin thermoplastic elastomer is added to the second component. Therefore, the second component containing the polyolefin polymer has bending elasticity that is considered to be derived from the thermoplastic elastomer, and the bending tends to be insufficient with the composite fiber having only the polyolefin polymer as the second component. It is presumed that the recovery property and the repeated bending fatigue resistance are improved, and the repeated compression durability required for the cushion material and the like is improved. Furthermore, since the thermoplastic elastomer to be added is an olefin-based thermoplastic elastomer, both the first component and the second component are composed of a polyolefin-based polymer, so that the fiber assembly after use can be easily recycled.

  In the crimped conjugate fiber of the present invention, when the second component is a polyolefin polymer, the olefinic thermoplastic elastomer added to the second component is an α-olefin containing an α-olefin rubbery polymer as a soft segment. It is preferable that it is an olefin type thermoplastic elastomer. The olefinic thermoplastic elastomer and α-olefinic thermoplastic elastomer are preferably olefinic thermoplastic elastomers polymerized using a metallocene catalyst.

  Although it does not specifically limit as said alpha olefin type rubber-like polymer, For example, it is preferable to use the copolymer of ethylene and C3-C20 alpha olefin. Examples of the α-olefin include propylene, 1-butene, 1-pentene, 3,3-dimethyl-1-butene, 4-methyl-1-pentene, 4,4-dimethyl-1-pentene, 1-decene, Examples include 1-dodecene, 1-tetradecene, 1-octadecene and the like. Although it does not specifically limit as a hard segment contained in the said olefin type thermoplastic elastomer, For example, polyolefin polymers, such as a polypropylene and a polypropylene, can be used. It does not specifically limit as said polypropylene, For example, a homopolymer, a random copolymer, a block copolymer, or mixtures thereof can be used. Examples of the random copolymer and block copolymer include a copolymer of propylene and at least one α-olefin selected from the group consisting of ethylene and an α-olefin having 4 or more carbon atoms. The α-olefin having 4 or more carbon atoms is not particularly limited, but examples thereof include 1-butene, 1-pentene, 3,3-dimethyl-1-butene, 4-methyl-1-pentene, and 4,4-dimethyl. Examples include -1-pentene, 1-decene, 1-dodecene, 1-tetradecene, and 1-octadecene.

  When a polyolefin-based polymer such as polypropylene is used as the second component, the content of the olefin-based thermoplastic elastomer added to the second component is preferably 3 to 25 when the entire second component is 100% by mass. It is mass%, More preferably, it is 3-20 mass%, Most preferably, it is 5-15 mass%. In the second component, when the content of the olefinic thermoplastic elastomer is 3% by mass or more, the addition of the elastomer component to the second component makes the entire second component elastic. The repeated compressive residual strain resistance and the compressive residual strain resistance of the fiber aggregate using the compressible conjugate fiber can be improved. In the second component, when the content of the olefin-based thermoplastic elastomer is 25% by mass or less, the repetitive compressive residual strain resistance is not adversely affected on the spinnability and stretchability of the crimped conjugate fiber, This is a crimped conjugate fiber capable of obtaining a fiber aggregate having excellent resistance to compression residual strain.

The density of the olefin thermoplastic elastomer is preferably 0.8~1.0g / cm ^3, more preferably 0.85~0.88g / cm ^3. If it is within the above range, it is excellent in heat resistance, and in a fiber assembly using crimped conjugate fibers, if it is the same volume, a lighter fiber assembly can be obtained, so it is preferably used for applications where weight reduction is required. It is done.

  According to ASTM D 2240 of the olefinic thermoplastic elastomer, the Shore A hardness measured using a type A durometer is preferably 50 to 95, more preferably 60 to 90, and 65 to 85. It is particularly preferred. The olefin-based thermoplastic elastomer added to the second component has a well-balanced durability and heat resistance against repeated bending of nonwoven fabrics using the crimped conjugate fiber obtained by satisfying the above range. It becomes. If the Shore A hardness is less than 50, the added olefinic thermoplastic elastomer itself is too soft, so that the resulting crimped conjugate fiber and fiber aggregate are easily deformed, and the bending recovery property and bulk recovery property are poor. Can be a thing. In addition, when the Shore A hardness exceeds 95, the added olefinic thermoplastic elastomer is too hard, so the bending elasticity resulting from the addition of the olefinic thermoplastic elastomer to the second component is not exhibited, and bending recovery is achieved. And the bulk recovery property when repeatedly compressed tends to decrease.

  Although the melting peak temperature of the olefinic thermoplastic elastomer used in the present invention is not particularly limited, the heat treatment for producing the fiber assembly from the crimped conjugate fiber obtained, the use of the fiber assembly, and the fiber assembly In view of the heat resistance, the melting peak temperature of the olefinic thermoplastic elastomer is preferably 70 ° C. or higher and 170 ° C. or lower. More preferably, it is 100 degreeC or more and 160 degrees C or less, and it is especially preferable that it is more than melting point temperature of polybutene-1 contained in a 1st component and 160 degrees C or less. When the melting peak temperature of the olefinic thermoplastic elastomer contained in the second component is 70 ° C. or higher and 170 ° C. or lower, the heat resistance is high, and when obtaining a fiber aggregate from the crimped conjugate fiber obtained. Even in the heat treatment to be performed, the bulk is hardly reduced, and a bulky fiber aggregate can be easily obtained. In addition, when the fiber aggregate is actually used, the bulk recoverability at high temperature is good, so that the crimped conjugate fiber and the fiber aggregate are particularly suitable for applications requiring heat resistance.

  The melt flow rate of the olefinic thermoplastic elastomer is not particularly limited, but is measured according to JIS-K-7210 (MFR; measurement temperature 230 ° C., load 2.16 kgf (21.18 N), below. In this case, the MFR is preferably 1 to 30 g / 10 min. A more preferred MFR 230 is 3 to 20 g / 10 min, and a particularly preferred MFR 230 is 5 to 15 g / 10 min. When the MFR230 of the olefinic thermoplastic elastomer is within the above range, the take-up property and the stretchability are improved. When the melting peak temperature satisfies the above range in combination with MFR230, the olefinic thermoplastic elastomer to be used has good heat resistance. Therefore, when obtaining a fiber aggregate from the crimped conjugate fiber obtained. Even in the heat treatment to be performed, the bulk is hardly reduced, and a bulky fiber aggregate can be easily obtained. In addition, when the fiber aggregate is actually used, the bulk recoverability at high temperature is good, so that the crimped conjugate fiber and the fiber aggregate are particularly suitable for applications requiring heat resistance.

  There are various olefinic thermoplastic elastomers that satisfy the above-mentioned density, Shore A hardness (Shore A hardness), melting peak temperature, and melt flow rate. Among them, olefinic thermoplastic elastomers polymerized using a metallocene catalyst. Is preferably used. In the case of an olefinic thermoplastic elastomer polymerized without using a metallocene catalyst, the crystal structure and amorphous structure portions in the elastomer are dispersed in a size of 300 nm to 1 μm. If the hard segment and the soft segment are elastomers of the above size and dispersed in the polymer, the bending elasticity of the elastomer itself and the bending elasticity and bulk recovery of fibers and nonwoven fabrics containing the elastomer are poor, and in addition, melt spinning tends to be difficult There is. In contrast, in an olefinic thermoplastic elastomer polymerized using a metallocene catalyst, the crystal structure and amorphous structure portions in the elastomer are dispersed in a size of 5 to 50 nm. By adding an elastomer having the above structure to the second component (core component) of the crimpable conjugate fiber, the resulting crimpable conjugate fiber has excellent heat resistance, bulk recovery and strain resistance after repeated deformation. It tends to be excellent. Examples of the olefinic thermoplastic elastomer polymerized using the above metallocene catalyst include, but are not limited to, “Notio” (registered trademark) manufactured by Mitsui Chemicals, Inc.

  In any case where a polyester-based polymer is used as the main component of the second component and a polyolefin-based polymer is used as the main component of the second component, The two components can be further blended with a polymer. In addition, the second component can be added with various known additives as long as the effects of the present invention are not hindered and the fiber productivity, the nonwoven fabric productivity, the thermal adhesiveness, and the touch are not affected. Is possible. Additives that can be added to the second component include known crystal nucleating agents, antistatic agents, pigments, matting agents, heat stabilizers, light stabilizers, flame retardants, antibacterial agents, lubricants, plasticizers, softeners, etc. They can be mixed depending on the application.

  In the crimped conjugate fiber of the present invention, the position of the center of gravity of the second component is shifted from the position of the center of gravity of the conjugate fiber. FIG. 1 shows a schematic diagram of a fiber cross section of a crimped conjugate fiber according to an 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 composite fiber 10. As a result, the surface of the first component 1 is melted during thermal bonding. The gravity center position 3 of the second component 2 is shifted from the gravity center position 4 of the composite fiber 10, and the ratio of the shift (hereinafter also referred to as the eccentricity ratio) is obtained by enlarging the fiber cross section of the crimped composite fiber with an electron microscope or the like. When the image is taken and the center of gravity position 3 of the second component 2 is C1, the center of gravity position 4 of the conjugate fiber 10 is Cf, and the radius 5 of the conjugate fiber 10 is rf, the numerical value shown by the following formula 2 is used.

[Equation 2]

  The fiber cross section in which the center of gravity position 3 of the second component 2 is displaced from the center of gravity position 4 of the composite fiber is preferably an eccentric core-sheath type or a parallel type as 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 fiber cross section is preferable in that desired wave shape crimps and / or spiral crimps can be easily expressed. The eccentricity ratio of the eccentric core-sheath composite fiber is preferably 5 to 50%. A more preferable eccentricity is 7 to 30%. Further, the shape of the second component 2 in the fiber cross section may be oval, Y-shaped, X-shaped, well-shaped, polygonal, star-shaped or the like in addition to the circular shape. In addition to the circular shape, an elliptical shape, a Y shape, an X shape, a well shape, a polygonal shape, a star shape, or a hollow shape may be used.

  In the crimped conjugate fiber of the present invention, as shown in FIG. 1, in the fiber cross section, the first component is arranged as the sheath component of the conjugate fiber, the second component is arranged as the core component, and the center of gravity of the second component When the position is an eccentric core-sheath structure deviated from the position of the center of gravity of the composite fiber, the composite ratio (core / sheath) of the second component and the first component is preferably 8/2 to 2/8 in volume ratio. More preferably, it is 7/3 to 3/7, and still more preferably 6/4 to 4/6. The second component serving as the core component mainly contributes to the bulk recovery property, and the first component serving as the sheath component mainly contributes to the strength of the nonwoven fabric and the hardness of the nonwoven fabric. When the composite ratio is 8/2 to 2/8, the strength and hardness of the nonwoven fabric and the bulk recoverability can be compatible. When the first component that is a sheath component is too much, the strength of the nonwoven fabric is increased, but the resulting nonwoven fabric tends to be hard and the bulk recovery is also poor. On the other hand, if the amount of the second component that is the core component is too large, the adhesion point is too small, and the strength of the nonwoven fabric tends to be small, and the bulk recoverability tends to be poor.

  FIG. 2 shows the crimped form of the crimped conjugate fiber in one embodiment of the present invention. In the present invention, “the composite fiber expresses three-dimensional crimp” means that the crimp shape in which the crimpable conjugate fiber expresses includes a wave crimp and / or a spiral crimp. . The corrugated crimp referred to in the present invention refers to a curved crest as shown in FIG. 2A. In addition, the spiral crimp indicates that the peak portion of the crimp as shown in FIG. 2B is spirally curved. Crimps in which corrugated crimps and spiral crimps are mixed as shown in FIG. 2C are also included in the crimped form of the three-dimensional crimps that the crimped conjugate fiber of the present invention exhibits. In the case of normal mechanical crimping as shown in FIG. 3, the crimped mountain has a sharp angle, that is, a so-called serrated crimp, and it tends to be difficult to increase the initial bulk when the nonwoven fabric is used. There is. Furthermore, it is inferior to the surface elasticity against compression, the so-called spring effect, and there is a tendency that sufficient initial bulk recovery is not obtained. In addition, as shown in FIG. 4, a crimp in which a sharp crimp of a mechanical crimp and a wave crimp are mixed, and although not shown in the figure, a sharp crimp of a mechanical crimp and a spiral crimp. Are included in the crimped form of the three-dimensional crimp that the crimped conjugate fiber of the present invention develops.

  In the crimpable conjugate fiber of the present invention, particularly the crimping in which the wave-shaped crimp and the spiral crimp shown in FIG. Is preferable.

  Hereinafter, the manufacturing method of the crimpable conjugate fiber of this invention is demonstrated.

  First, a method for producing an actual crimpable conjugate fiber, which is one form of the crimped conjugate fiber of the present invention, will be described.

  First, a first component containing polybutene-1 and linear low-density polyethylene, a polymer having a melting peak temperature 20 ° C. or more higher than the melting peak temperature of polybutene-1, or a polymer having a melting start temperature of 120 ° C. or more. Prepare a second component containing. Next, in the fiber cross section, the first component occupies at least 20% of the surface of the composite fiber, and the center of gravity of the second component is displaced from the center of gravity of the composite fiber, for example, an eccentric core-sheath type composite The first component and the second component are supplied to the nozzle, the second component is melt-spun at a spinning temperature of 220 to 350 ° C., and the first component is melt-spun at a spinning temperature of 200 to 300 ° C. The spinning temperature of the second component is selected according to the type of polymer. If a polyolefin polymer such as polypropylene or polymethylpentene is used, the spinning temperature is 220 ° C. to 330 ° C., polyethylene terephthalate, polytrimethylene terephthalate, poly If a polyester polymer such as butylene terephthalate is used, it is preferable to perform melt spinning at a spinning temperature of 240 to 350 ° C.

  The first component and the second component are supplied to the eccentric core-sheath type composite nozzle at the above spinning temperature, and taken at a take-up speed of 100-1500 m / min to obtain an undrawn spun filament with a fineness of 2-120 dtex. Next, the stretching temperature is set to 40 ° C. or more and lower than the melting point of the first component, and the stretching process is performed at a stretching ratio of 1.8 times or more. A more preferable lower limit of the stretching temperature is 50 ° C. or higher. A more preferable upper limit of the stretching temperature is a temperature 10 ° C. lower than the melting point of the first component. If the stretching temperature is less than 40 ° C., crystallization of the first component is difficult to proceed, so that thermal shrinkage tends to increase or bulk recovery properties tend to decrease. If the stretching temperature is equal to or higher than the melting point of the first component, the fibers tend to be fused. A more preferable lower limit of the draw ratio is 2 times. A more preferable upper limit of the draw ratio is 4 times. When the draw ratio is 1.8 times or more, the draw ratio is not too low, and it becomes easy to obtain a fiber in which the above-described wave-shaped crimp and / or spiral crimp are expressed, and the initial bulk and the rigidity of the fiber itself are obtained. However, it is not inferior in nonwoven fabric processability such as card passing property and bulk recovery. The stretching method is not particularly limited, and wet stretching is performed while being heated with a high-temperature liquid such as high-temperature hot water, dry stretching is performed while being heated in a high-temperature gas or a high-temperature metal roll, and 100 ° C. or higher. A known stretching process such as steam stretching, in which stretching is performed while heating the fiber under normal pressure or pressurized state, can be performed. Among these, wet stretching using warm water is preferable because productivity, economy, and the whole unstretched fiber bundle can be easily and uniformly heated. Moreover, you may anneal-treat in atmospheres, such as 90-120 degreeC dry heat, wet heat, and steam, before and after the said extending | stretching as needed.

  In the actual crimpable conjugate fiber which is one form of the crimpable conjugate fiber of the present invention, the melting peak temperature of the polybutene-1 contained in the second component constituting the actual crimpable conjugate fiber is 20 Polyolefin polymers such as homopolypropylene, ethylene-propylene copolymer, and ethylene-butene-1-propylene terpolymer are polymers having a melting peak temperature higher by ℃ or higher, or polymers having a melting start temperature of 120 ℃ or higher. The stretching temperature is preferably 40 ° C. or higher and below the melting peak temperature of polybutene-1 contained in the first component, more preferably 50 ° C. or higher and 100 ° C. or lower, and 60 ° C. or higher and 90 ° C. or lower. Is particularly preferred. On the other hand, in the actual crimpable conjugate fiber which is one form of the crimpable conjugate fiber of the present invention, from the melting peak temperature of the polybutene-1 contained in the second component constituting the actual crimpable conjugate fiber. When the polymer having a melting peak temperature higher than 20 ° C. or the polymer having a melting start temperature of 120 ° C. or higher is a polyester-based polymer such as polyethylene terephthalate, polytrimethylene terephthalate, or polybutylene terephthalate, the stretching temperature is 60 ° C. It is preferable that it is below the melting peak temperature of polybutene-1 contained in the said 1st component above, 70 degreeC or more and 100 degrees C or less are more preferable, It is especially preferable that they are 75 degreeC or more and 95 degrees C or less.

  Next, before or after applying the fiber treatment agent as necessary, a crimp of 5 to 25 crimps / 25 mm is applied using a known crimper such as a stuffer box type crimper. A more preferable number of crimps is 8 to 20 pieces / 25 mm, and a particularly preferable number of crimps is 10 to 18 pieces / 25 mm. The crimped shape after passing through the crimper may be a serrated 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 initial volume 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 tends to be reduced. .

  Furthermore, it is preferable that after the crimping is performed by the above-described crimping machine, the annealing treatment is performed at a temperature at which the three-dimensional crimp is developed at a temperature at which the unstretched fiber bundle is not fused. If it is a crimpable conjugate fiber of the present invention and the first component is a conjugate fiber made of a polymer containing polybutene-1, the preferred temperature range is 90 to 120 ° C, dry heat, wet heat, or steam It is preferable to carry out the annealing treatment in the atmosphere. Specifically, it is preferable that the fiber treatment agent is applied and then crimped by a crimping machine, and the drying process is performed simultaneously with the annealing process in a dry heat atmosphere of 90 to 120 ° C. because the process can be simplified. . When the annealing treatment is performed at 90 ° C. or higher, the dry heat shrinkage rate is not increased, and a predetermined actual crimp is easily obtained, the formation of the resulting nonwoven fabric is not disturbed, and the productivity can be improved. In the annealing treatment, a more preferred treatment temperature range is 90 to 115 ° C, and it is particularly preferred to carry out at 95 to 110 ° C.

  The actual crimped conjugate fiber obtained by the above method mainly has at least one kind of crimp selected from corrugated crimp and spiral crimp shown in FIG. Preferably, at least one selected from a wave crimp, only a spiral crimp, a crimp mixed with a wave crimp and a spiral crimp, and a crimp mixed with a wave crimp and a serrated crimp. It has a kind of crimp, and particularly preferably has at least one kind of crimp selected from only a crimp with a crimp, only a crimp with a crimp, and a crimp with a mixture of a crimp with a crimp and a spiral. Crimp expression state. Moreover, since the number of crimps of the above-mentioned actual crimpable conjugate fiber is 5/25 mm or more and 25/25 mm or less, a bulky nonwoven fabric can be obtained without deteriorating card passing properties. It is possible and preferable. And it cut | disconnects to desired fiber length, and an actual crimpable composite fiber is obtained. A more preferable number of crimps is 8 to 20 pieces / 25 mm, and a particularly preferable number of crimps is 10 to 18 pieces / 25 mm.

  In addition, the above-described actual crimpable conjugate fiber is manifested by manifesting at least one type of three-dimensional crimp selected from a wave-shaped crimp and a spiral crimp by manifesting a crimp in the composite fiber, and manifesting it by manifesting it. have. In the fiber state, it may be an actual crimp in which a three-dimensional crimp is completely manifested, or an apparent crimp that has a slight possibility of the occurrence of a crimp (the occurrence of crimp is generated when heat is applied to the fiber). It may be. However, when heat is applied to the fibers (for example, when a temperature to be processed into a nonwoven fabric described later is applied), if the number of crimps exceeds 25/25 mm, the card passing property may be reduced. Yes, not preferred.

  Next, the manufacturing method of the latent crimpable composite fiber which is another form of the crimpable composite fiber of this invention is demonstrated.

  First, a first component containing polybutene-1 and linear low-density polyethylene, a polymer having a melting peak temperature 20 ° C. or more higher than the melting peak temperature of polybutene-1, or a polymer having a melting start temperature of 120 ° C. or more. Prepare a second component containing. Next, in the fiber cross section, the first component occupies at least 20% of the surface of the composite fiber, and the center of gravity of the second component is displaced from the center of gravity of the composite fiber, for example, an eccentric core-sheath type composite The first component and the second component are supplied to the nozzle, the second component is melt-spun at a spinning temperature of 220 to 350 ° C., and the first component is melt-spun at a spinning temperature of 200 to 300 ° C. The spinning temperature of the second component is selected according to the type of polymer. If a polyolefin polymer such as polypropylene or polymethylpentene is used, the spinning temperature is 220 ° C. to 330 ° C., polyethylene terephthalate, polytrimethylene terephthalate, poly If a polyester polymer such as butylene terephthalate is used, it is preferable to perform melt spinning at a spinning temperature of 240 to 350 ° C.

  The first component and the second component are supplied to the eccentric core-sheath type composite nozzle at the above spinning temperature, and taken at a take-up speed of 100-1500 m / min to obtain an undrawn spun filament with a fineness of 2-120 dtex. Next, the stretching temperature is set to 40 ° C. or higher and lower than the melting point of the first component, and stretching is performed at a stretch ratio of 1.5 times or more. A more preferable lower limit of the stretching temperature is 50 ° C. or higher. A more preferable upper limit of the stretching temperature is a temperature 10 ° C. lower than the melting point of the first component. If the stretching temperature is less than 40 ° C., crystallization of the first component is difficult to proceed, so that thermal shrinkage tends to increase or bulk recovery properties tend to decrease. If the stretching temperature is equal to or higher than the melting point of the first component, the fibers tend to be fused. A more preferable lower limit of the draw ratio is 2 times. A more preferable upper limit of the draw ratio is 4 times. When the draw ratio is 1.5 times or more, the draw ratio is not too low, and when heat-treated, there is a tendency that crimps are likely to appear, the initial bulk and the rigidity of the fiber itself are not reduced, card passing properties, etc. The nonwoven fabric processability and bulk recovery are not inferior. The stretching method is not particularly limited, and wet stretching is performed while being heated with a high-temperature liquid such as high-temperature hot water, dry stretching is performed while being heated in a high-temperature gas or a high-temperature metal roll, and 100 ° C. or higher. A known stretching process such as steam stretching, in which stretching is performed while heating the fiber under normal pressure or pressurized state, can be performed. Among these, wet stretching using warm water is preferable because productivity, economy, and the whole unstretched fiber bundle can be easily and uniformly heated.

  In the latent crimpable conjugate fiber that is one form of the crimpable conjugate fiber of the present invention, it is 20 higher than the melting peak temperature of the polybutene-1 contained in the second component constituting the latent crimpable conjugate fiber. Polymers having a melting peak temperature higher than ℃, or polymers having a melting start temperature of 120 ℃ or more are polyolefins such as propylene homopolymer, ethylene-propylene copolymer and ethylene-butene-1-propylene terpolymer. In the case of a polymer, the stretching temperature is preferably 40 ° C. or higher and lower than the melting peak temperature of polybutene-1 contained in the first component, more preferably 50 ° C. or higher and 100 ° C. or lower, and 60 ° C. or higher and 90 ° C. or lower. It is particularly preferred. On the other hand, in the latent crimpable conjugate fiber which is one form of the crimpable conjugate fiber of the present invention, from the melting peak temperature of the polybutene-1 contained in the second component constituting the latent crimpable conjugate fiber. When the polymer having a melting peak temperature higher than 20 ° C. or the polymer having a melting start temperature of 120 ° C. or higher is a polyester-based polymer such as polyethylene terephthalate, polytrimethylene terephthalate, or polybutylene terephthalate, the stretching temperature is 60 ° C. It is preferable that it is below the melting peak temperature of polybutene-1 contained in the said 1st component above, 70 degreeC or more and 100 degrees C or less are more preferable, It is especially preferable that they are 75 degreeC or more and 95 degrees C or less.

  Next, before or after applying the fiber treatment agent as necessary, a crimp of 5 to 25 crimps / 25 mm is applied using a known crimper such as a stuffer box type crimper. A more preferable number of crimps is 8 to 20 pieces / 25 mm, and a particularly preferable number of crimps is 10 to 18 pieces / 25 mm. If the number of crimps is less than 5 pieces / 25 mm, or the number of crimps exceeds 25 pieces / 25 mm, the card passing property may be deteriorated.

  Further, after crimping with the above crimper, dry heat, wet heat, or steam at 50 to 100 ° C., preferably 60 to 90 ° C., more preferably 60 to 80 ° C., particularly preferably 60 to 75 ° C. It is preferable to carry out the annealing treatment in the atmosphere. Specifically, after the fiber treatment agent is applied, crimping is performed with a crimping machine, and the drying process is performed simultaneously with the annealing process in a dry heat atmosphere of 50 to 90 ° C., because the process can be simplified. preferable. By setting the annealing temperature to 50 to 90 ° C., a desired heat shrinkage rate can be obtained, and a latent crimpable conjugate fiber that exhibits steric crimps when heat-treated can be obtained. Moreover, the fiber with high card | curd permeability can be obtained.

  The crimped conjugate fiber of the present invention, that is, the actual crimped conjugate fiber or latent crimped conjugate fiber of the present invention, is dried by performing the above-described annealing treatment, and then the filament is cut according to the use. The fiber length to be cut is 1 to 120 mm, and is selected according to the use, and after producing a fiber web with a card machine, the nonwoven fabric is manufactured by a known nonwoven fabric manufacturing method such as an air-through method, a needle punch method, or a hydroentanglement method. Is cut to a fiber length of 20 to 100 mm, preferably 30 to 90 mm, more preferably 40 to 80 mm. If a non-woven fabric is produced by a method of producing a fiber web by the so-called air raid method that opens air, the fiber length is preferably cut to 1 to 40 mm, preferably 1 to 30 mm, more preferably 3 to 25 mm. . If a wet nonwoven fabric is produced by a papermaking method, the fiber length is preferably cut to 1 to 20 mm, preferably 1 to 10 mm, more preferably 3 to 8 mm. In addition, the crimped conjugate fiber of the present invention can be used as it is without cutting the annealed filament depending on the application.

  The crimped conjugate fiber of the present invention, that is, the actual crimped conjugate fiber or the latent crimped conjugate fiber of the present invention is not particularly limited in its fineness, and is used as a substitute material for urethane foam. Mattresses such as cotton and bedding, seats for vehicles and chairs, cushion materials for clothing such as shoulder pads and bra pads, sanitary materials, packaging materials, wet tissues, filters, sponge-like porous wiping materials, sheet-like wiping It can be finished to a fineness suitable for each use, such as various non-woven fabrics such as materials, various beddings such as comforters and mattresses that make use of the elasticity and shape recovery of composite fibers, and use as cotton in clothing articles. However, it is preferable that it is 1-60 dtex since it is excellent in elasticity, the bulk recovery property when made into a nonwoven fabric, and tactile sensation. A more preferable range of fineness is 2 to 50 dtex, 4 to 30 dtex is particularly preferable, and 4 to 20 dtex is most preferable.

  The fiber assembly of the present invention contains at least 30% by mass of the crimped conjugate fiber. When the crimped conjugate fiber is contained in an amount of 30% by mass or more, the elasticity and bulk recovery of the fiber assembly can be maintained high. Examples of the fiber aggregate include a knitted fabric, a woven fabric, a nonwoven fabric, a stuffing, a pad, and a fiber web. The fiber aggregate preferably contains 30 to 100% by mass of the crimped conjugate fiber and 0 to 70% by mass of fibers other than the crimped conjugate fiber. The fiber other than the crimped conjugate fiber contained in the fiber assembly is not particularly limited as long as it does not hinder the performance of the crimped conjugate fiber. For example, at least 1 type of fiber chosen from a synthetic fiber, a chemical fiber, a natural fiber, and an inorganic fiber is included.

  The production method of the fiber aggregate containing the crimped conjugate fiber of the present invention is not particularly limited, and after forming a fiber web by a known method, it becomes known such as an air-through method, a needle punch method, a hydroentanglement method, or the like. The crimped conjugate fiber disclosed in Japanese Patent Application Laid-Open No. 2001-207360 and Japanese Patent Application Laid-Open No. 2002-242061 is also referred to as ball-shaped cotton (also referred to as fiber ball). The above-described ball-shaped cotton is blown into a mold and heat-treated to form a fiber aggregate having a predetermined shape. However, a method for producing a nonwoven fabric after forming a fiber web is preferred. Examples of the fiber web form constituting the nonwoven fabric of the present invention include a parallel web, a semi-random web, a random web, a cross lay web, a Chris cross web, and an air lay web. The said fiber web exhibits a still higher effect, when a 1st component adhere | attaches by heat processing. The fiber web may be subjected to a needle punching process or a hydroentanglement process as necessary before thermal processing. The thermal processing means is not particularly limited as long as the crimped conjugate fiber of the present invention is sufficiently exerted, such as a hot air through heat treatment machine, a hot air up-and-down heat treatment machine, and an infrared heat treatment machine. It is preferable to use a heat treatment machine that does not require much pressure such as wind pressure.

  Further, the fiber that can be blended with the fiber web using the crimped conjugate fiber of the present invention (hereinafter also referred to as mixed fiber) is not particularly limited as long as it does not lose the performance of the crimped conjugate fiber of the present invention. Not. For example, single fibers of polyester such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate, polyethylene such as low density polyethylene, high density polyethylene, linear low density polyethylene A single fiber of polypropylene, a single fiber of polypropylene such as isotactic, atactic and syndiotactic polymerized using a conventional Ziegler-Natta catalyst or metallocene catalyst, or a copolymer of monomers of these polyolefins, Or a single fiber of polyolefin such as polyolefin using a metallocene catalyst (also referred to as Kaminsky catalyst) when polymerizing these polyolefins, nylon 6, nylon 66, nylon 11, nano Single fibers of polyamides such as Ron 12, mention may be made of acrylic nitrile (poly) single fibers of acrylic, polycarbonate, polyacetal, polystyrene, a single fiber of engineering plastics, such as cyclic polyolefin. Here, “single fiber” refers to a fiber composed of only one kind of polymer component. Moreover, as said mixed fiber, the composite fiber containing at least 1 or more types of polymer component can also be used in the range which does not lose the performance of the crimpable composite fiber of this invention. Examples of the composite fiber include a composite fiber obtained by combining different types of resins such as polyester, polyolefin, polyamide, engineering plastic, or resins (for example, polyethylene terephthalate and polytrimethylene terephthalate) made of the same type of different polymer components. Is mentioned. In the above-mentioned composite fiber, the composite state is not particularly limited, and the cross-sectional shape in the fiber cross section is a core-sheath type composite fiber, an eccentric core-sheath type composite fiber, a parallel type composite fiber, and a citrus tufted resin component are alternately arranged. It may be a split type composite fiber or a sea-island type composite fiber. In the crimpable conjugate fiber of the present invention, when the second component is a polyolefin polymer, since most of the polymer components constituting the crimpable conjugate fiber are polyolefin polymers, a single fiber comprising a polyolefin polymer In addition, it is preferable from the viewpoint of the recyclability of the fiber assembly that a composite fiber in which polyolefin polymers are combined is used as a mixed fiber.

  In addition, the crimped conjugate fiber of the present invention is excellent in thermal adhesiveness. Therefore, not only synthetic fibers made from the above thermoplastic resins but also natural fibers such as cellulosic fibers, viscose rayon, tencel (registered) Trademark), lyocell (registered trademark), semi-synthetic fibers (also referred to as regenerated fibers) such as cupra, inorganic fibers such as glass fibers, and carbon fibers exhibit thermal adhesiveness. Examples of the natural fibers include plant natural fibers and animal natural fibers. Plant-based natural fibers include ramie, linen (flax), kenaf (marine hemp), abaca (manila hemp), heneken (sisal hemp), jute (burlap), hemp (cannabis), palm, palm, mulberry, mitsumata , Bagasse and the like. Examples of animal natural fibers include silk, wool, Angola, cashmere, and mohair. As the fiber blended with the crimped conjugate fiber of the present invention, any of vegetable natural fibers and animal natural fibers can be used, but plant natural fibers are preferred because the cost required for cultivation is low.

  The fiber web containing the crimped conjugate fiber of the present invention can be made into a bulky fiber assembly by performing heat processing even in a single layer state, but the fiber web is laminated before performing heat processing. By laminating the fiber assembly after the web or heat processing to obtain a laminate of the fiber assembly, a fiber assembly having more excellent bulkiness can be easily obtained. Moreover, in the said fiber assembly, it is preferable that the fiber which comprises a fiber assembly is arranged in parallel with the thickness direction of a fiber assembly, in other words, is arranged in the longitudinal direction of a fiber assembly. This is because the fibers constituting the fiber assembly are arranged in parallel to the thickness direction, whereby good bulk recovery and cushioning properties can be obtained with respect to the pressure applied to the thickness direction. In the present invention, the fibers constituting the fiber assembly are arranged in parallel to the thickness direction of the fiber assembly (arranged in the longitudinal direction of the fiber assembly). When the acute angle formed with the thickness direction is 45 ° or less, that is, when the fiber assembly is cut in the thickness direction and the cut surface is enlarged and observed with an optical microscope or a scanning electron microscope, The acute angle with the thickness direction of the fiber assembly is 45 ° or less. And it is more preferable that 80% or more of the total number of all the constituent fibers of the fiber assembly observed in the cut surface of a certain area is arranged in the longitudinal direction of the fiber assembly. As described above, the fiber assembly in which the fibers constituting the fiber assembly are arranged in parallel to the thickness direction can be manufactured using a known manufacturing method. For example, the fiber web is corrugated. However, the present invention is not limited to these, and is not limited to these.

  When the crimped conjugate fiber contained in the fiber web is the manifest crimped conjugate fiber, the heat processing temperature of the fiber web is the wave-like crimp and / or the spiral crimp of the crimped conjugate fiber that is expressed. What is necessary is just to set to the temperature range in which shrinkage | contraction does not lose | disappear at the time of heat processing, for example, when the melting peak temperature of polybutene-1 is set to Tm, it is less than the melting peak temperature of 2nd component, Preferably Tm- 10 (° C.) to Tm + 80 (° C.), particularly preferably Tm (° C.) to Tm + 50 (° C.), and most preferably 130 to 160 ° C. By the heat processing, at least one resin component contained in the first component of the manifest crimpable conjugate fiber is melted, and the constituent fibers are thermally fused. In particular, when at least polybutene-1 of the above-described actual crimpable conjugate fiber is melted and the constituent fibers are heat-sealed, a stronger intersection between the fibers can be formed, and the bulk recoverability is increased, which is preferable. .

  When the crimped conjugate fiber contained in the fiber web is the latent crimped conjugate fiber, it may be set to a temperature range in which crimp is expressed. For example, when the melting peak temperature of polybutene-1 is Tm, Tm-10 (° C) to less than the melting point of the second component, preferably Tm-10 (° C) to Tm + 60 (° C), particularly preferably Tm (° C) to Tm + 50 (° C), most preferably 130 to It is preferable to set in the range of 160 ° C. Through heat processing, at least one resin component contained in the first component of the latent crimpable conjugate fiber is melted, and the constituent fibers are heat-sealed. In particular, when at least polybutene-1 of the latent crimpable conjugate fiber is melted and the constituent fibers are heat-sealed, it is possible to form a stronger intersection between the fibers, which increases the bulk recovery and is preferable. .

  The nonwoven fabric preferably has a compressive residual strain rate of 45% or less, more preferably 35% or less, measured according to method A of JIS-K-6400-4. The compressive residual strain rate indicates the degree of change in the hardness of the nonwoven fabric when heated to 70 ° C. The smaller this value, the more the deterioration of the fiber or nonwoven fabric due to heat is suppressed, and the bulk recovery property is excellent. Indicates that

  Moreover, it is preferable that the said nonwoven fabric has 15% or less of the repetition compression residual strain rate measured according to B method of JIS-K-6400-4, and it is more preferable that it is 12% or less. The above-mentioned repeated compression residual strain rate indicates the degree of change in the hardness of the nonwoven fabric when 50% compression is repeated 80,000 times. The smaller this value, the more the deterioration of the fiber or nonwoven fabric due to compression is suppressed. This indicates that the bulk recovery property is excellent.

  The textile product of the present invention has at least a part of the above fiber assembly, and includes hard cotton, bedding, a vehicle seat, a chair, a shoulder pad, a bra pad, clothing, a hygiene material, a packaging material, a wet tissue, a filter, It is formed into a sponge-like porous wiping material, a sheet-like wiping material, or stuffed cotton.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

  The measurement method and evaluation method used in this example are as follows.

(Q value)
I. Analyzing device to be used (i) Cross-separation device “CFC T-100” (hereinafter referred to as CFC) manufactured by Dia Instruments Co., Ltd.
(Ii) Fourier transform infrared absorption spectrum analysis (FT-IR), “1760X” manufactured by PerkinElmer
A fixed wavelength infrared spectrophotometer attached as a CFC detector is removed and an FT-IR is connected instead, and this FT-IR is used as a detector. The transfer line from the outlet of the solution eluted from the CFC to the FT-IR is 1 m long, and the temperature is maintained at 140 ° C. throughout the measurement. The flow cell attached to the FT-IR has an optical path length of 1 mm and an optical path diameter of 5 mmφ, and the temperature is maintained at 140 ° C. throughout the measurement.
(Iii) Gel permeation chromatography (GPC)
For the GPC column at the rear stage of the CFC, three “AD806MS” manufactured by Showa Denko KK are connected in series.

II. CFC measurement conditions (i) Solvent: orthodichlorobenzene (ODCB)
(Ii) Sample concentration: 1 mg / mL
(Iii) Injection volume: 0.4 mL
(Iv) Column temperature: 140 ° C
(V) Solvent flow rate: 1 mL / min

III. Measurement conditions of FT-IR After elution of the sample solution starts from GPC at the latter stage of the CFC, FT-IR measurement is performed under the following conditions to collect GPC-IR data.
(I) Detector: MCT
(Ii) Resolution: 8 cm-1
(Iii) Measurement interval: 0.2 minutes (12 seconds)
(Iv) Number of integrations per measurement: 15 times

IV. Post-processing and analysis of measurement results The molecular weight distribution is obtained using the absorbance at 2945 cm-1 obtained by FT-IR as a chromatogram. Conversion from the retention volume to the molecular weight is performed using a calibration curve prepared in advance with standard polystyrene. Standard polystyrenes used are “F380”, “F288”, “F128”, “F80”, “F40”, “F20”, “F10”, “F4”, “F1”, “A5000” manufactured by Tosoh Corporation. , “A2500”, “A1000”. A calibration curve is prepared by injecting 0.4 mL of a solution dissolved in ODCB (containing 0.5 mg / mL dibutylhydroxytoluene (BHT)) so that each is 0.5 mg / mL. The calibration curve uses a cubic equation obtained by approximation by the least square method. Conversion to molecular weight uses a general-purpose calibration curve with reference to “Size Exclusion Chromatography” written by Sadao Mori (Kyoritsu Shuppan). The following numerical values are used for the viscosity equation ([η] = K × Mα) used at that time.
(I) Calibration curve using standard polystyrene K = 0.000138, α = 0.70
(Ii) Polypropylene sample measurement: K = 0.000103, α = 0.78

  In the above, it is measured by GPC (Gel Permeation Chromatography), but when measured by another model, it is described in 2005 Plastic Molding Material Commerce Manual (Chemical Industry Daily, published on August 30, 2004). As described above, measurement can be performed simultaneously with “MG03B” manufactured by Nippon Polypro Co., Ltd., and the value when MG03B indicates 3.5 can be used as the blank condition, and the measurement can be performed by adjusting the condition.

(Spinnability during melt spinning)
The spinnability of the crimped conjugate fiber was evaluated according to the following criteria based on the occurrence state and frequency of yarn breakage when melt spinning for 30 minutes continuously.
A: The number of yarn breaks is 0 to 2 in 30 minutes of continuous melt spinning, and the spinnability is good.
B: Although the number of yarn breaks is 3 to 5 in 30 minutes of continuous melt spinning, there is no problem in the process.
C: The number of yarn breakage is 6 times or more in 30 minutes of continuous melt spinning, or yarn breakage occurs frequently and spinning is impossible.

(Extensible)
The drawability of the crimped conjugate fiber was evaluated according to the following criteria based on the occurrence of yarn breakage during the drawing process and the passability of the stuffer box type crimper used for crimping.
A: Yarn breakage hardly occurs in the drawing process, and the stuffer box type crimper passes easily, so there is no problem in production.
B: In the drawing process, thread breakage or clogging in the stuffer box type crimping machine occurs, but there is no problem in production.
C: Productivity is very poor because yarn breakage frequently occurs and winding around the drawing tank and drawing roll occurs, or clogging frequently occurs in the stuffer box type crimper or at the discharge port.

(Raw cotton defibration)
The raw cotton spreadability of the crimped conjugate fiber is determined by the card processability (card passing property, nep generation status and the obtained web) when the web is collected by applying 100% by mass of each crimped conjugate fiber to a parallel card. The following criteria were used for evaluation.
A: Since the fiber easily passes through the parallel card and almost no nep is generated, a web with good formation can be obtained.
B: Nep occurs slightly, but does not significantly affect the web formation.
C: The card cannot be passed or the web cannot be obtained because a large amount of neps occur.

(Development of raw cotton crimp of the actual crimpable composite fiber)
The tow after the completion of the drying process (100 ° C., 15 minutes annealing and drying process) was visually observed and evaluated by the following criteria for the raw cotton crimp expression of the actual crimpable conjugate fiber.
A: A three-dimensional crimp appears and it is easy to confirm the shape of a spiral crimp and / or a wavy crimp.
B: Although three-dimensional crimps are manifested, it is somewhat difficult to determine the shape of spiral crimps and / or wavy crimps, and serrated crimps are also mixed.
C: Neither mechanical crimp (sawtooth crimp) nor solid crimp (spiral crimp and / or wavy crimp) can be confirmed, and most of the crimp disappears.

(Generation of raw cotton crimp of latent crimpable composite fiber)
The tow after the completion of the drying process (100 ° C., 15 minutes annealing and drying process) was visually observed and evaluated based on the following criteria for the raw cotton crimp expression of the latent crimpable conjugate fiber.
A: The mechanical crimp applied by the stuffer box type crimping machine is not lost, and the sawtooth shape can be easily confirmed.
B: The mechanical crimp applied by the stuffer box type crimper is slightly lost, and there is a portion where a saw-tooth shape is not seen.
C: Neither mechanical crimp (sawtooth crimp) nor solid crimp (spiral crimp and / or wavy crimp) can be confirmed, and most of the crimp disappears.

(Crimp expression after thermal processing of actual crimpable composite fiber)
After the thermal processing of the actual crimpable conjugate fiber, the crimp expression after the heat treatment was obtained by applying 100% by mass of each crimpable conjugate fiber to a parallel card, collecting a web, and processing temperature at 150 ° C. with a hot air circulation type heat treatment machine. The web after being treated for 30 seconds was visually observed and evaluated according to the following criteria.
A: The developed three-dimensional crimp does not disappear, and it is easy to confirm the shape of the spiral crimp and / or the wavy crimp.
B: Although some of the developed three-dimensional crimps have disappeared, the shape of the helical crimp and / or the wavy crimp can be determined.
C: The developed three-dimensional crimp almost disappears and it is difficult to confirm the crimped shape.

(Crimp expression after thermal processing of latent crimpable composite fiber)
The latent crimpable conjugate fiber is subjected to crimping after heat processing, and 100% by mass of each crimpable conjugate fiber is placed on a parallel card, a web is collected, and the processing temperature at 150 ° C. is processed by a hot air circulation type heat treatment machine. The web after being treated for 30 seconds was visually observed and evaluated according to the following criteria.
A: A three-dimensional crimp is developed by heat treatment, and it is easy to confirm the shape of a spiral crimp and / or a wavy crimp.
B: The expression of the three-dimensional crimp is weak or the three-dimensional crimp expressed by heat has partially disappeared, but the shape of the helical crimp and / or the wavy crimp can be determined.
C: The expression of the three-dimensional crimp is weak, or the three-dimensional crimp expressed by heat almost disappears and it is difficult to confirm the crimp shape.

(Measurement of melting point (Tf1, Tf2) of each component after spinning)
Using DSC manufactured by Seiko Co., Ltd., increasing the sample amount to 3.2 mg and increasing the temperature from room temperature to 200 ° C. (300 ° C. when a polyester polymer is used as the second component) at a temperature increase rate of 10 ° C./min. After warming, it was cooled to 40 ° C. at a cooling rate of 10 ° C./min, and the melting point Tf1 of the first component after spinning and the melting point Tf2 of the second component after spinning were determined from the obtained heat of fusion curve. Regarding the melting point after spinning, when two peaks appeared, the low-temperature peak was the melting point (Tf1) of the first component, and the high-temperature peak was the melting point (Tf2) of the second component. When measuring the melting point after spinning, when three or more peaks appear, only the last peak, that is, the peak on the highest temperature side is set as the melting point (Tf2) of the second component, and the remaining peaks are all The melting point (Tf1) after spinning in each polymer constituting one component was used.

(Compressive residual strain rate)
According to A method of JIS-K-6400-4, the strain rate after compression for 22 hours was measured at a temperature of 70 ° C. ± 1 ° C. and a compression rate of 50%, and was defined as a compression residual strain rate. The thickness was measured under no load without applying a force in the thickness direction of the test piece, and a metal straight scale defined in JIS-B-7516 was used for the measurement.

(Repeated compression residual strain rate)
According to B method of JIS-K-6400-4, the strain rate after 80,000 compressions was measured at 23 ° C. and a compression rate of 50%, and was set as a repeated compression residual strain rate. The thickness was measured under no load without applying a force in the thickness direction of the test piece, and a metal straight scale defined in JIS-B-7516 was used for the measurement.

The polymers used in this example are as follows.
(1) PET (“T200E” manufactured by Toray Industries, Inc., melting peak temperature (melting point): 255 ° C., IV value: 0.64)
(2) PP-A (“SA03E” manufactured by Nippon Polypro Co., Ltd., melting peak temperature (melting point): 160 ° C., MFR230: 20 g / 10 min, Q value: 5.6)
(3) PP-B (“SA01A” manufactured by Nippon Polypro Co., Ltd., melting peak temperature (melting point): 160 ° C., MFR230: 9 g / 10 min, Q value: 3.2)
(4) PB-1 (“DP0401M” manufactured by Sun Allomer, melting peak temperature (melting point): 123 ° C., MFR190: 20 g / 10 min)
(5) LLDPE-A (Nippon Polyethylene “Kernel” (registered trademark) “KS560T” [linear low-density polyethylene synthesized by a high-pressure method using a metallocene catalyst], melting peak temperature (melting point): 90 C, MFR190: 16.5 g / 10 min, density: 0.898 g / cm ³ , Q value: 2.5, flexural modulus: 62 MPa)
(6) LLDPE-B (“420SD” manufactured by Ube Maruzen Polyethylene Co., Ltd. [Linear low density polyethylene synthesized by a gas phase method using a metallocene catalyst], melting peak temperature (melting point): 118 ° C., MFR 190 ° C .: (7 g / 10 min, density: 0.918 g / cm ³ , Q value: 3.0, flexural modulus: 280 MPa)
(7) LLDPE-C (Nippon Polyethylene “Kernel” (registered trademark) “KC571” [linear low-density polyethylene synthesized by a high-pressure method using a metallocene catalyst], melting peak temperature (melting point): 100 (° C., MFR 190: 12 g / 10 min, density: 0.907 g / cm ³ , Q value: 2.2, flexural modulus: 110 MPa)
(8) LLDPE-D (“Harmolex” (registered trademark) “NJ744N” manufactured by Nippon Polyethylene Co., Ltd. [Linear low density polyethylene synthesized by gas phase method using metallocene catalyst], melting peak temperature (melting point): 120 ° C., MFR 190: 12 g / 10 min, density: 0.911 g / cm ³ , Q value: 2.5, flexural modulus: 120 MPa)
(9) LLDPE-E (“631J” manufactured by Ube Maruzen Polyethylene Co., Ltd. [Linear low density polyethylene synthesized by a gas phase method using a metallocene catalyst], melting peak temperature (melting point): 121 ° C., MFR 190: 20 g / 10 minutes, density: 0.931 g / cm ³ , Q value: 2.9, flexural modulus: 600 MPa)
(10) LDPE (“LJ802” manufactured by Nippon Polyethylene Co., Ltd., melting peak temperature (melting point): 106 ° C., MFR 190: 22 g / 10 min, density: 0.918 g / cm ³ )
(11) PPR-1 (polypropylene-based thermoplastic elastomer, “Notio” (registered trademark) “2070” manufactured by Mitsui Chemicals, Inc., an olefin-based thermoplastic elastomer synthesized with a metallocene catalyst), melting peak temperature (melting point): 138 ° C. , Shore A hardness (ASTM D 2240): 75, MFR230: 6 g / 10 min, density 0.867 g / cm ³ )
(12) PPR-2 (polyolefin-based thermoplastic elastomer, “Adflex V109F” manufactured by Basell, melting peak temperature (melting point): 143 ° C., Shore D hardness (ASTM D 2240): 41, MFR230: 12 g / 10 min, density 0.880 g / cm ³ )
(13) BP (butene-propylene copolymer, “5C37F” manufactured by Sun Allomer, melting peak temperature (melting point): 132 ° C., MFR230: 6 g / 10 min)
(14) EMAA (“Nuclele” (registered trademark) “AN4213C” manufactured by Mitsui DuPont, density: 0.940 g / cm ³ , melting peak temperature (melting point): 88 ° C., MFR 190: 10 g / 10 min)

  In the above, the IV value is the above-mentioned intrinsic viscosity, and MFR230 is a melt flow rate measured at 230 ° C. and 21.18 N (2.16 kgf) according to JIS-K-7210. Moreover, MFR190 is the melt flow rate measured by 190 degreeC and 21.18N (2.16kgf) according to JIS-K-7210.

Hereinafter, the manufacturing conditions of the crimped conjugate fiber will be described.
(A) Extrusion temperature: The second component was 300 ° C., the first component was 250 ° C., and the nozzle cap temperature was 270 ° C.
(B) Take-up speed: 500 m / min
(C) Number of nozzle holes: 600 holes (D) Composite ratio: Core / sheath = 55/45 (volume ratio)
(E) Unstretched fineness: 10 dtex
(F) Stretching temperature: wet 80 ° C
(G) Stretch ratio: 2.3 times (H) Crimp: 12-16 pieces / 25 mm
(I) Annealing temperature (drying temperature), time: 100 ° C., 15 minutes (J) Product fineness (single fiber): 6.0 dtex
(K) Fiber length: 51 mm

(Nonwoven fabric manufacturing conditions)
A web was collected by applying 100% by mass of each crimped conjugate fiber to a parallel card, and treated with a hot air circulation type heat treatment machine at a processing temperature of 150 ° C. for 30 seconds to obtain a nonwoven fabric having a basis weight of 500 g / m ² . .

Example 1
Using only PP-A as the second component and using a mixture of PB-1 and LLDPE-A having a mass ratio of PB-1 / LLDPE-A = 92/8 as the first component, A crimped conjugate fiber was produced under the production conditions of the conjugate fiber. Subsequently, using the crimped conjugate fiber obtained, a nonwoven fabric was produced under the above-described nonwoven fabric production conditions.

(Example 2)
A mixture of PP-A and PPR-1 having a mass ratio of PP-A / PPR-1 = 85/15 was used as the second component, and a mass ratio of PB-1 / LLDPE-A = 97 / was used as the first component. A crimped conjugate fiber and a nonwoven fabric were produced in the same manner as in Example 1 except that a mixture of PB-1 and LLDPE-A, which was 3, was used.

(Example 3)
A mixture of PP-A and PPR-1 having a mass ratio of PP-A / PPR-1 = 85/15 was used as the second component, and a mass ratio of PB-1 / LLDPE-A = 95 / was used as the first component. A crimped conjugate fiber and a nonwoven fabric were produced in the same manner as in Example 1 except that a mixture of PB-1 and LLDPE-A, which was No. 5, was used.

Example 4
As the second component, a crimped conjugate fiber and a crimped conjugate fiber were used in the same manner as in Example 1 except that a mixture of PP-A and PPR-1 having a mass ratio of PP-A / PPR-1 = 85/15 was used. A nonwoven fabric was prepared.

(Example 5)
A mixture of PP-A and PPR-1 having a mass ratio of PP-A / PPR-1 = 85/15 was used as the second component, and a mass ratio of PB-1 / LLDPE-A = 80 / was used as the first component. A crimped conjugate fiber and a nonwoven fabric were produced in the same manner as in Example 1 except that a mixture of PB-1 and LLDPE-A, which was 20, was used.

(Example 6)
A mixture of PP-A and PPR-1 having a mass ratio of PP-A / PPR-1 = 85/15 was used as the second component, and a mass ratio of PB-1 / LLDPE-B = 92 / was used as the first component. A crimped conjugate fiber and a nonwoven fabric were produced in the same manner as in Example 1 except that a mixture of PB-1 and LLDPE-B, which was 8, was used.

(Example 7)
A mixture of PP-A and PPR-1 having a mass ratio of PP-A / PPR-1 = 85/15 was used as the second component, and a mass ratio of PB-1 / LLDPE-C = 92 / was used as the first component. A crimped conjugate fiber and a nonwoven fabric were produced in the same manner as in Example 1 except that a mixture of PB-1 and LLDPE-C, which was 8, was used.

(Example 8)
As the second component, the crimped conjugate fiber and the crimped conjugate fiber were obtained in the same manner as in Example 1 except that a mixture of PP-A and PPR-1 having a mass ratio of PP-A / PPR-1 = 95/5 was used. A nonwoven fabric was prepared.

Example 9
As the second component, a crimped conjugate fiber and a crimped conjugate fiber were used in the same manner as in Example 1 except that a mixture of PP-A and PPR-1 having a mass ratio of PP-A / PPR-1 = 75/25 was used. A nonwoven fabric was prepared.

(Example 10)
As the second component, a crimped conjugate fiber and a crimped conjugate fiber were obtained in the same manner as in Example 1 except that a mixture of PP-B and PPR-1 having a mass ratio of PP-B / PPR-1 = 85/15 was used. A nonwoven fabric was prepared.

(Example 11)
As the second component, a crimped conjugate fiber and a crimped conjugate fiber were used in the same manner as in Example 1 except that a mixture of PP-A and PPR-2 having a mass ratio of PP-A / PPR-2 = 85/15 was used. A nonwoven fabric was prepared.

(Example 12)
A crimped conjugate fiber and nonwoven fabric in the same manner as in Example 1 except that a mixture of PB-1 and LLDPE-D having a mass ratio of PB-1 / LLDPE-D = 92/8 was used as the first component. Was made.

(Example 13)
A crimped conjugate fiber and nonwoven fabric in the same manner as in Example 1 except that a mixture of PB-1 and LLDPE-E having a mass ratio of PB-1 / LLDPE-E = 92/8 was used as the first component. Was made.

(Example 14)
As in Example 1, except that a mixture of PB-1, LLDPE-D and EMAA having a mass ratio of PB-1 / LLDPE-D / EMAA = 90/5/5 was used as the first component, A compressible conjugate fiber and a nonwoven fabric were produced.

(Example 15)
Example 1 except that only the PET was used as the second component, and a mixture of PB-1 and LLDPE-D having a mass ratio of PB-1 / LLDPE-D = 92/8 was used as the first component. Similarly, crimped conjugate fibers and nonwoven fabrics were produced.

(Example 16)
A crimped conjugate fiber and a nonwoven fabric were produced in the same manner as in Example 1 except that only PET was used as the second component.

(Example 17)
Except for using only PET as the second component and using a mixture of PB-1, LLDPE-D, and EMAA as the first component, the mass ratio of PB-1 / LLDPE-D / EMAA = 90/5/5 Produced crimpable conjugate fibers and nonwoven fabric in the same manner as in Example 1.

(Example 18)
Except for using only PET as the second component and using a mixture of PB-1, LLDPE-A and EMAA as the first component, the mass ratio of PB-1 / LLDPE-A / EMAA = 90/5/5 Produced crimpable conjugate fibers and nonwoven fabric in the same manner as in Example 1.

(Comparative Example 1)
Except that a mixture of PP-A and PPR-1 having a mass ratio of PP-A / PPR-1 = 85/15 was used as the second component, and only PB-1 was used as the first component. In the same manner as in Example 1, crimped conjugate fibers and nonwoven fabrics were produced.

(Comparative Example 2)
A mixture of PP-A and PPR-1 having a mass ratio of PP-A / PPR-1 = 85/15 was used as the second component, and a mass ratio of PB-1 / LLDPE-A = 70 / was used as the first component. Except for using a mixture of PB-1 and LLDPE-A, which was 30, an attempt was made to produce a crimped conjugate fiber in the same manner as in Example 1. Since yarn breakage occurred frequently, a spun filament could not be produced.

(Comparative Example 3)
A mixture of PP-A and PPR-1 having a mass ratio of PP-A / PPR-1 = 99/1 is used as the second component, and a mass ratio of PB-1 / LDPE = 90/10 is used as the first component. A crimped conjugate fiber and a nonwoven fabric were produced in the same manner as in Example 1 except that a certain mixture of PB-1 and LDPE was used.

(Comparative Example 4)
As the second component, a mixture of PP-A and PPR-1 having a mass ratio of PP-A / PPR-1 = 85/15 was used, and the mass ratio was PB-1 / EMAA = 94/6 as the first component. Except that a mixture of PB-1 and EMAA was used, production of crimped conjugate fiber and nonwoven fabric was attempted in the same manner as in Example 1, but the stretchability of the spun filament was poor. In addition, the crimp development after heat processing to make a nonwoven fabric was poor, and a heat-bonding nonwoven fabric with good cushioning properties could not be produced.

(Comparative Example 5)
As the second component, a mixture of PP-A and PPR-1 having a mass ratio of PP-A / PPR-1 = 85/15 is used, and as the first component, the mass ratio is PB-1 / BP = 85/15. A crimped conjugate fiber and a nonwoven fabric were produced in the same manner as in Example 1 except that a certain mixture of PB-1 and BP was used.

(Comparative Example 6)
Except for using only PET as the second component and using a mixture of PB-1, PP-A and EMAA as the first component, the mass ratio of PB-1 / PP-A / EMAA = 85/10/5 Tried to produce crimped conjugate fibers and nonwoven fabric in the same manner as in Example 1. A composite fiber having high spinnability, stretchability, and crimp development was obtained. However, a heat-bonding nonwoven fabric was not obtained because heat-bonding at 150 ° C. did not sufficiently heat-bond the constituent fibers.

(Comparative Example 7)
As in Example 1, except that only PET was used as the second component and a mixture of PB-1 and EMAA having a mass ratio of PB-1 / EMAA = 92/8 was used as the first component, A compressible conjugate fiber and a nonwoven fabric were produced.

  The eccentricity of the crimped conjugate fibers of Examples 1 to 18 and Comparative Examples 1 to 7, the spinnability during melt spinning, the raw cotton defibration, the raw cotton crimp expression, and the crimp expression after heat processing Tables 1 to 4 below show the results of the properties, and the initial thickness, basis weight, repeated compression residual strain, and compression residual strain of the nonwoven fabric. Note that the crimped conjugate fibers of Examples 1 to 4, 6 to 9, and 11 to 18 become apparently crimped conjugate fibers, and the wavy crimp or the spiral crimp shown in FIG. 2A, or the wavy crimp and the spiral. Both crimps were expressed, and the number of crimps was 12-18 pieces / 25 mm. In addition, the crimped conjugate fibers of Examples 5 and 10 become latently crimped conjugate fibers, exhibiting three-dimensional crimps by thermal processing when producing the nonwoven fabric, and the wavy crimps and spirals shown in FIG. 2A At least one of the crimps was expressed.

  When Examples 1 to 18 in Tables 1 to 3 and Comparative Examples 1 to 7 in Table 4 are compared, in the crimped conjugate fiber containing PB-1 as the first component, linear low density polyethylene is added to the PB-1. The effect of improving the properties such as the stretchability of PB-1, the raw cotton defibration property, and the crimping property of the raw cotton was confirmed. This is shown in Comparative Examples 1, 4, 5, and 7 in Table 4, in which the first component is a composite fiber composed only of PB-1, or a composite fiber in which a polymer other than linear low-density polyethylene is added to PB-1. It can be confirmed that the stretchability is low (Evaluation A) in all Examples, whereas the stretchability is low (Evaluation B). Moreover, since the composite fiber in which low density polyethylene (LDPE) is added to the first component is not good in the openability of the raw cotton, as a polymer to be added to the first component containing polybutene-1 as a main component, linear low By adding high-density polyethylene, not only spinnability and stretchability, but also the crimpability of the raw cotton can be obtained. It can be confirmed that it is obtained.

  In the crimped conjugate fiber of the present invention, the first component is a resin component containing polybutene-1 and linear low-density polyethylene, and the second component is either a polyolefin-based polymer or a polyester-based polymer. Even if it exists, it can confirm from Examples 1-18 that the nonwoven fabric using the obtained composite fiber turns into a nonwoven fabric with a low compression residual distortion repeatedly. Therefore, in the crimped conjugate fiber of the present invention, the second component constituting the inside of the conjugate fiber is not particularly limited, and a polymer having a melting peak temperature higher than the melting peak temperature of polybutene-1 by 20 ° C. or onset of melting A polymer having a temperature of 120 ° C. or higher and having excellent bending strength and bending elasticity can be used without being limited to polyester polymers and polyolefin polymers.

  In the crimpable composite fiber containing PB-1 as the first component, when adding the linear low density polyethylene to the first component, the composite in which 20% by mass of the linear low density polyethylene is added to the first component The fiber has good spinnability, whereas the composite fiber with 30% by mass of linear low-density polyethylene added to the first component has extremely poor spinnability. It can be inferred from a comparison between Example 5 and Comparative Example 2 that the amount has an upper limit and the upper limit of the amount added is less than 30% by mass, preferably 25% by mass or less.

  In the crimpable conjugate fibers of Examples 1 to 18, the crimp development properties of the obtained crimpable conjugate fibers, the resistance to repeated compression residual strain of nonwoven fabrics using the crimpable conjugate fibers, and the improvement of compression residual strain resistance In particular, in the crimped conjugate fibers of Examples 2 to 4, 7 to 9, 11, 12, and 14 and the nonwoven fabric using the same, the residual compression strain was 11.5% or less, the residual compression strain It can be confirmed that the rate is greatly improved as compared with the nonwoven fabric of Comparative Example 1 of 31.5% or less. When Examples 2 to 4, 7 to 9, 11, 12, and 14 are compared with Examples 6 and 13, linear low density polyethylene having relatively high density and high flexural modulus is used for Examples 6 and 13. In the crimped conjugate fiber of the present invention, the linear low-density polyethylene added to the first component is heat-bonded because the repeated compressive residual strain and compressive residual strain of the nonwoven fabric containing the crimped conjugate fiber increased. It is presumed that it is preferable to add linear low-density polyethylene having a lower density and a lower flexural modulus within a range that does not affect the properties and heat resistance.

  As shown in Comparative Example 6, in the crimped conjugate fiber containing PB-1 as the first component, the conjugate fiber in which polypropylene is added to the first component also improves the spinnability and stretchability of PB-1, and the raw cotton It can be confirmed that a crimped conjugate fiber excellent in the spreadability, the crimping property of the raw cotton, and the crimping property of the raw cotton after heat processing can be obtained. However, in the crimped conjugate fiber shown in Comparative Example 6, the apparent melting point of the first component is increased because polypropylene having a higher melting point than PB-1 is added to the first component. As a result, it was confirmed that the composite fibers could not be sufficiently thermally bonded under the conditions of this thermal bonding process. Therefore, by comparing the melting point (Tf1) of the first component after spinning of Examples 1 to 18 and Comparative Example 6, especially Examples 1, 6, 7, 12, 13 and Comparative Example 6, at a lower temperature. In the crimpable composite fiber containing PB-1 as the first component, linear low density polyethylene is used as the first component. It can be confirmed that the addition is optimal.

  The fiber assembly using the crimped conjugate fiber of the present invention is excellent in both initial bulk and bulk recoverability, and is made of hard cotton such as cushioning material, hygiene materials, packaging materials, cosmetic materials, and female bras. Low density non-woven fabric products such as pads and shoulder pads, and wiping materials for humans and objectives, powder or liquid cosmetic coating materials, heat insulating materials and sound absorbing materials, which generally use urethane foam and urethane sponge It is preferably used for applications. In addition, the crimped conjugate fiber of the present invention is excellent in elasticity and shape recoverability, and is therefore preferably used as stuffed cotton in various beddings and clothing articles such as comforters and mattresses. In addition, the crimpable conjugate fiber of the present invention in which the second component is a polyolefin polymer, which is one form of the crimped conjugate fiber of the present invention, is such that all of the resin components constituting the conjugate fiber are composed of a polyolefin polymer. Therefore, after being used as the above-mentioned hard cotton, stuffed cotton, and low density nonwoven fabric products, it can be easily recovered and reused as a raw material consisting of polyolefin polymer, reused as a resin raw material, and reused as polyolefin fiber. It is also preferably used for various fiber assembly products that require subsequent collection and recycling of raw materials.

DESCRIPTION OF SYMBOLS 1 1st component 2 2nd component 3 Center of gravity position of 2nd component 4 Center of gravity position of composite fiber 5 Radius of composite fiber 10 Composite fiber

Claims (11)

A composite fiber comprising a first component and a second component,
The first component includes polybutene-1 and linear low density polyethylene,
The content of the linear low density polyethylene in the first component is 2 to 25% by mass,
The second component includes a polymer having a melting peak temperature that is 20 ° C. or more higher than the melting peak temperature of polybutene-1 or a polymer having a melting start temperature of 120 ° C. or more.
When viewed from the fiber cross section, the first component occupies at least 20% of the surface of the composite fiber, and the center of gravity of the second component is deviated from the center of gravity of the composite fiber,
The crimped conjugate fiber, wherein the conjugate fiber is an actual crimp that exhibits a three-dimensional crimp or a latent crimp that exhibits a three-dimensional crimp when heated.   The crimped conjugate fiber according to claim 1, wherein the three-dimensional crimp is at least one type of three-dimensional crimp selected from a wave crimp and a spiral crimp.   The crimped conjugate fiber according to claim 1 or 2, wherein the linear low-density polyethylene is a copolymer with an α-olefin polymerized using a metallocene catalyst. The linear low density polyethylene has a melting peak temperature determined by DSC measured according to JIS-K-7121 of 80 to 130 ° C. and a density measured according to JIS-K-7112 of 0.88 to The crimped conjugate fiber according to any one of claims 1 to ^3, which is 0.92 g / cm ³ .   The crimped conjugate fiber according to any one of claims 1 to 4, wherein the linear low-density polyethylene has a flexural modulus of 20 to 300 MPa measured according to JIS-K-7171.   The polymer having a melting peak temperature higher by 20 ° C or higher than the melting peak temperature of polybutene-1 or a polymer having a melting start temperature of 120 ° C or higher contained in the second component is a polyolefin-based polymer. The crimpable conjugate fiber according to any one of the above.   The polyolefin-based polymer contained in the second component is homopolypropylene, and the homopolypropylene contained in the second component is 75 to 100% by mass when the entire second component is 100% by mass. The crimpable conjugate fiber described in 1.   The polymer having a melting peak temperature higher by 20 ° C or higher than the melting peak temperature of polybutene-1 or a polymer having a melting start temperature of 120 ° C or higher contained in the second component is a polyester-based polymer. The crimpable conjugate fiber according to any one of the above. Containing 30% by mass or more of crimped conjugate fiber,
The crimped conjugate fiber is a conjugate fiber containing a first component and a second component,
The first component includes polybutene-1 and linear low density polyethylene,
The content of the linear low density polyethylene in the first component is 2 to 25% by mass,
The second component includes a polymer having a melting peak temperature that is 20 ° C. or more higher than the melting peak temperature of polybutene-1 or a polymer having a melting start temperature of 120 ° C. or more.
When viewed from the fiber cross section, the first component occupies at least 20% of the surface of the composite fiber, and the center of gravity of the second component is deviated from the center of gravity of the composite fiber,
The fiber assembly is characterized in that the composite fiber is an actual crimp that exhibits a three-dimensional crimp or a latent crimp that exhibits a three-dimensional crimp when heated.   The fiber assembly according to claim 9, wherein the fiber assembly includes 0 to 70% by mass of at least one fiber selected from synthetic fibers, chemical fibers, natural fibers, and inorganic fibers in addition to the crimped conjugate fibers. .   It has at least a part of the fiber assembly according to claim 9 or 10, hard cotton, bedding, vehicle seat, chair, shoulder pad, brassiere pad, clothing, hygiene material, packaging material, wet tissue, filter, A textile product characterized by being formed into a sponge-like porous wiping material, a sheet-like wiping material, or stuffed cotton.

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