JP2011021300A - Crimping composite fiber and fibrous mass comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crimping composite fiber and a fibrous mass having high bulkiness recovery in repeated compression, and containing a polyolefin polymer in both of a core component and a sheath component. <P>SOLUTION: The composite fiber 10 comprises a first component 1 and a second component 2, wherein the first component 1 comprises polybutene-1 and the second component 2 comprises either a polyolefin polymer having a melting peak temperature higher by ≥20°C than that of the polybutene-1 or a polyolefin polymer having a melting initiation temperature of ≥120°C, and an olefinic thermoplastic elastomer. The content of the olefinic thermoplastic elastomer in the second component 2 is 3-25 mass%, the first component 1 accounts for at least 20% of the surface of the composite fiber 10 in a fiber cross-section, the gravity center position 3 of the second component 2 is apart from the gravity center position 4 of the composite fiber 10, and the composite fiber 10 is actually crimped or potentially crimped. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fiber aggregate mainly having high resilience and bulk recovery, and particularly to an actual crimpable conjugate fiber suitable for a nonwoven fabric, a latent crimpable conjugate fiber, and a fiber assembly 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 non-woven fabrics.

  For example, Patent Documents 1 to 3 propose a nonwoven fabric excellent in bulk recovery using a composite fiber mainly composed of a core component containing a polyester polymer and a sheath component containing a polyolefin polymer. Yes. However, in these composite fibers, when the core component includes a polyester-based polymer and the sheath component includes a polyolefin-based polymer, it may be difficult to recycle the used nonwoven fabric.

  On the other hand, both the core component and the sheath component are commercially available as composite fibers containing polyolefin-based polymers and non-woven fabrics using the same. However, when the load is repeatedly applied, a decrease in bulk recovery is seen, such as cushioning materials. However, there is a problem that fibers and nonwoven fabrics suitable for applications requiring high bulk recovery even after repeated compression have not been obtained.

JP 2003-3334 A JP 2007-126806 A JP 2008-248421 A

  In order to solve the above-mentioned conventional problems, the present invention has a high bulk recoverability when repeatedly compressed, and a crimpable conjugate fiber containing a polyolefin polymer in both the core component and the sheath component, and a fiber assembly using the same I will provide a.

  The crimpable conjugate fiber of the present invention is a conjugate fiber containing a first component and a second component, wherein the first component contains polybutene-1, and the second component has a melting peak temperature of polybutene-1. A polyolefin polymer having a melting peak temperature higher than 20 ° C. or a polyolefin polymer having a melting start temperature of 120 ° C. or higher, and an olefin thermoplastic elastomer, and the inclusion of the olefin thermoplastic elastomer in the second component The amount is 3 to 25% by mass, 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 an actual crimp that expresses a three-dimensional crimp, or a latent crimp that develops a three-dimensional crimp by heating.

  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 the second component is a polyolefin polymer having a melting peak temperature of 20 ° C. or more higher than the melting peak temperature of polybutene-1, or a polyolefin polymer having a melting start temperature of 120 ° C. or more, and an olefin heat The content of the olefinic thermoplastic elastomer in the second component is 3 to 25% by mass, and when viewed from the fiber cross section, the first component contains at least 20% of the surface of the composite fiber. The center of gravity of the second component is deviated from the position of the center of gravity of the composite fiber, and the composite fiber is manifestly crimped to express three-dimensional crimps, or is heated. Characterized in that it is a latent crimp that express more steric crimps.

  The crimpable conjugate fiber of the present invention has a polyolefin polymer having a melting peak temperature of 20 ° C. or more higher than the melting peak temperature of polybutene-1 in the second component or a melting start temperature in the second component. By including a polyolefin polymer having a temperature of 120 ° C. or higher and an olefin thermoplastic elastomer, the fiber has excellent spinnability, stretchability, crimp development, and the like. And the nonwoven fabric which is excellent in bulk recovery property and is excellent also in recyclability can be obtained by using the crimpable conjugate fiber of this invention.

  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, since the resin components that make up the composite fiber are all made of polyolefin-based resins, they are used as the above-mentioned hard cotton, stuffed cotton, and low-density nonwoven fabric products, and then recovered as raw materials consisting of polyolefin-based resins, resin raw materials It can be easily reused as a polyolefin fiber and can be reused as a polyolefin-based fiber, and is preferably used in various fiber aggregate products that require fractional collection after use and reuse of raw materials.

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.

(Second component)
The second component (core component) of the crimped conjugate fiber of the present invention is a polyolefin polymer having a melting peak temperature that is 20 ° C. or more higher than the melting peak temperature of polybutene-1, or a polyolefin having a melting start temperature of 120 ° C. or more. Based polymer (hereinafter also simply referred to as polyolefin polymer) and an olefinic thermoplastic elastomer. 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. In the present invention, the melting peak temperature obtained from the DSC curve is also referred to as the melting point.

  The polyolefin polymer in the second component is not particularly limited as long as it has a melting peak temperature that is 20 ° C. or more higher than the melting peak temperature of polybutene-1 or has a melting start temperature of 120 ° C. or more. For example, polyethylene, polypropylene, polybutylene, methylpentene resin, polybutadiene, or the like can be used. 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. By using a polyolefin polymer as the second component and using the polyolefin polymer together with the first component as described later, the crimped conjugate fiber of the present invention can be easily recycled.

  From the viewpoint of excellent bending strength, rigidity and the like, the polyolefin polymer in the second component is preferably polypropylene (hereinafter also referred to as PP). 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. The propylene content in the copolymer is preferably 50% by mass or more. 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 of the composite fiber, the recyclability after use, and the economy (production cost), the polyolefin polymer in the second component is particularly preferably a propylene homopolymer.

  The polypropylene in the second component is a melt flow rate measured at 230 ° C. according to JIS-K-7210 (MFR; measurement temperature 230 ° C., load 2.16 kgf (21.18 N), hereinafter referred to as MFR230). Is preferably 5 to 40 g / 10 min. More preferable MFR230 is 6-30 g / 10min. When the MFR230 is 5 to 40 g / 10 minutes, the heat resistance is good, the bulk recovery property at high temperature is high, and the take-up property and the drawability are good.

  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 preferably 3 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 crimps are manifested in the crimpable conjugate fiber, the Q value of polypropylene in the second component is preferably 4 to 9, and heating is performed. When the latent crimpable conjugate fiber that expresses steric crimp is to be obtained, the Q value is preferably 3 to 5.

  The crimped conjugate fiber of the present invention contains an olefinic thermoplastic elastomer as a second component. That is, the crimpable conjugate fiber itself is a crimpable conjugate fiber used as a constituent fiber of a fiber assembly suitable for applications requiring excellent bulk recovery properties such as cushioning materials and clothing pads, and strain resistance against repeated load. And the second component that contributes to the hardness, bulk recovery, and strain resistance of the fiber assembly including the crimped conjugate fiber, in other words, the component existing inside the core-sheath type conjugate fiber (core including the eccentric type) The sheath type composite fiber is also characterized by containing an olefinic thermoplastic elastomer in the core component). As the olefinic thermoplastic elastomer, polyolefin resin such as polyethylene and polypropylene is used as a hard segment, and ethylene propylene type such as ethylene-propylene rubber (EPM), ethylene-butene rubber (EBM), ethylene-propylene-diene rubber (EPDM), etc. Examples include thermoplastic elastomers using rubber as a soft segment. Examples of the olefinic thermoplastic elastomer include “Milastomer (registered trademark)” and “Notio (registered trademark)” manufactured by Mitsui Chemicals, Inc. “Esporex (registered trademark)” manufactured by Sumitomo Chemical Co., Ltd., Mitsubishi Chemical Corporation “Thermo Run (registered trademark)”, “Zeras (registered trademark)” manufactured by the company, and the like can be used. By adding an appropriate amount of an olefinic thermoplastic elastomer to the second component constituting the crimped conjugate fiber of the present invention, the second component has bending elasticity considered to be derived from the olefinic thermoplastic elastomer. Further, it is presumed that the bending recovery property and the repeated bending fatigue resistance, which were insufficient with the composite fiber containing only the polyolefin polymer as the second component, are improved, and the repeated compression durability required for the cushion material and the like is improved. Furthermore, recycling of the fiber assembly after use becomes easy by making the thermoplastic elastomer to be added an olefin-based thermoplastic elastomer.

  The olefinic thermoplastic elastomer in the second component is preferably an α-olefinic thermoplastic elastomer containing an α-olefinic rubbery polymer as a soft segment. 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.

  In the second component, the content of the olefinic thermoplastic elastomer is 3 to 25% by mass, preferably 3 to 20% by mass, more preferably 5 to 5% when the entire second component is 100% by mass. 15% by 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 spinnability of the crimpable conjugate fiber is not deteriorated, and the compressive residual strain resistance is not deteriorated. 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 0.83~0.89g / cm ^3, more preferably 0.85 to 0.88 g / 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. Also, when the Shore A hardness exceeds 95, the added olefinic thermoplastic elastomer is too hard, so the bending elasticity derived 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 melting peak temperature is determined from a DSC curve measured according to JIS-K-7121. In the present invention, the melting peak temperature determined from the DSC curve is also referred to as a melting point.

  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 metallocene catalyst include “Notio” manufactured by Mitsui Chemicals, Inc., but are not limited thereto.

(First ingredient)
In the crimped conjugate fiber of the present invention, the first component contains polybutene-1. 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 the crimped conjugate fiber of the present invention, the first component may be a resin component containing polybutene-1 and may be a resin component consisting only of polybutene-1, but the first component is polybutene-1. In addition, it is preferable to contain an olefin polymer different from the polybutene-1 or a copolymer polymer with an olefin having a polar group. When the first component contains polybutene-1 and further contains an olefin polymer different from polybutene-1 or a copolymer with an olefin having a polar group, the spinnability, stretchability and heat of polybutene-1 The heat shrinkability during processing is improved, and spinning / drawing and heat processing can be performed more stably.

  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. More preferable MFR190 is 3 to 25 g / 10 min, and particularly preferably 3 to 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.

  The olefin polymer different from the polybutene-1 or a copolymer with an olefin having a polar group is not particularly limited as long as it has an appropriate compatibility with the polybutene-1. For example, polyethylene such as low density polyethylene (LDPE), high density polyethylene (HDPE), and linear low density polyethylene (LLDPE) polymerized using ordinary Ziegler-Natta catalyst or metallocene catalyst, ordinary Ziegler-Natta catalyst And olefin polymers such as isotactic, atactic and syndiotactic polypropylene, polybutylene, methylpentene resin and polybutadiene polymerized using a metallocene catalyst. Further, for example, ethylene-methyl (meth) acrylate copolymer, ethylene-ethyl (meth) acrylate copolymer, ethylene-2-hydroxyethyl (meth) acrylate copolymer, propylene-ethyl (meth) acrylate copolymer, etc. An α-olefin- (meth) acrylate copolymer; an α-olefin-vinyl cyanide copolymer such as an ethylene-acrylonitrile copolymer, an ethylene-methacrylonitrile copolymer, and a propylene-acrylonitrile copolymer; Α-olefin-vinyl carboxylate copolymers such as ethylene-vinyl acetate copolymer and propylene-vinyl acetate copolymer; maleated polyolefin such as maleated polyethylene and maleated polypropylene; styrene-ethylene butene-styrene block Copolymer It can be used copolymer of an olefin having a polar group such as in compound. Among these, from the viewpoint of good compatibility with polybutene-1, polyethylene, polypropylene and ethylene-ethyl acrylate copolymer are preferable, polyethylene is more preferable, and linear low density polyethylene is particularly preferable. These polymers can use 1 type (s) or 2 or more types. In the copolymer with the olefin having a polar group, the content of the olefin component is preferably more than 50% by mass.

  The 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 further includes polyethylene, preferably linear low density polyethylene, particularly preferably linear low density polyethylene polymerized using a metallocene catalyst that satisfies the above-mentioned Q value range. In the crimped conjugate fiber of the present invention containing polybutene-1 as the first component, the 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, and the resulting crimped conjugate fiber has a crimper passing property and a desired fiber length. It is preferable because the defibration of the raw cotton after cutting into raw cotton (staple fiber) 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 bonding between uniform constituent fibers) is exhibited by the linear low density polyethylene contained in the first component of the crimped conjugate fiber. Furthermore, since linear low density polyethylene is excellent in impact resistance, the first component of the crimped conjugate fiber of the present invention containing linear low density polyethylene as the first component is used to thermally bond the constituent fibers. Even when the fiber aggregate is used in applications where repeated load is applied, the adhesion point between the fibers is not easily removed and peeling does not easily occur, and the repeated compressive residual strain resistance and the compressive residual strain resistance are excellent.

  The polyethylene in the first component 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), hereinafter referred to as MFR 190). Is preferably 1 to 80 g / 10 min. More preferable MFR190 is 3 to 25 g / 10 min, and particularly preferably 3 to 20 g / 10 min. When the MFR 190 is 1 to 80 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.

  The polyethylene in the first component 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 80-120 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.

Density polyethylene in the first component is preferably 0.870~0.930g / cm ^3, more preferably 0.880~0.920g / cm ^3. If it is in said range, compatibility with polybutene-1 is also favorable and heat resistance is also high. The density of the polyethylene is not particularly limited, but when the density of the polyethylene contained in the first component is larger than 0.930 g / cm ³ , the polyethylene added to the polybutene-1 becomes hard, and the characteristics of the polybutene-1 Is lost, the composite fiber as a whole tends to be hard, and there is a risk that the bulk recovery property and resistance to compressive residual strain of the resulting fiber aggregate will be reduced. Moreover, when the density of the polyethylene contained in the first component 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, room temperature in the range of 40 to 80 ° C. There is a risk that the bulk recovery at higher temperatures and the resistance to compressive residual strain will decrease.

  When the first component contains polybutene-1 and a copolymer of an olefin polymer different from polybutene-1 or an olefin having a polar group, the content of the polybutene-1 in the entire first component Is from 60 to 98% by mass, and the content of the olefin polymer different from the polybutene-1 or the copolymerized polymer with an olefin having a polar group is preferably from 40 to 2% by mass. If it is in said range, the flow characteristic of polybutene-1 will be improved, a uniform spinning can be performed stably, and stretchability will also be improved. Moreover, in said 1st component, the addition amount of the copolymer polymer with the olefin polymer different from the said polybutene-1 or the olefin which has a polar group may be less than 30 mass% with respect to the whole 1st component. Preferably, it is 3-25 mass%.

  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 1 is used.

  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 other than circular, and the shape of the composite fiber 10 in the fiber cross-section. 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 particularly 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. 2C are mixed can satisfy both the card passing property and the initial bulk and bulk recovery properties. 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, a polyolefin polymer having a melting peak temperature 20 ° C. or more higher than the melting peak temperature of polybutene-1, or a polyolefin polymer having a melting start temperature of 120 ° C. or more, and an olefin type A second component containing a thermoplastic elastomer is prepared. 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 240 to 330 ° C., the first component is melted at a spinning temperature of 200 to 300 ° C., and taken up at a take-up speed of 100 to 1500 m / min. Get the filament. Next, the stretching temperature is set to 40 ° C. or higher 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 higher. 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 perform an annealing process 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 An olefin polymer having a melting peak temperature higher than ℃ or an olefin polymer having a melting start temperature of 120 ℃ or more is obtained from a propylene homopolymer, an ethylene-propylene copolymer, and an ethylene-butene-1-propylene terpolymer. In the case of at least one selected from the group consisting of: It is particularly preferably 90 ° C. or lower.

  Next, before or after applying the fiber treatment agent as necessary, a crimp of 5/25 mm or more and 25/25 mm or less is performed using a known crimping machine such as a stuffer box type crimping machine. Give. 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, after applying the fiber treating agent, crimping is performed 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., thereby simplifying the process. It is preferable. 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.

  The actual crimped conjugate fiber obtained by the above method mainly has at least one kind of crimp selected from wave crimps and spiral crimps as shown in FIG. Since it is / 25 mm, a bulky nonwoven fabric can be obtained without deteriorating the card passing property, which is preferable. And it cut | disconnects to desired fiber length, and an actual crimpable composite fiber is obtained. A more preferable number of crimps is 10-20 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 state of the fiber, it may be an actual crimp in which the three-dimensional crimp is completely developed, or an actual crimp that has a possibility of the occurrence of a slight crimp (a three-dimensional crimp is developed when heat is applied to the fiber). It may be contracted. 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.

  2ndly, the manufacturing method of the latent crimpable conjugate fiber which is another form of the crimpable conjugate fiber of this invention is demonstrated.

  First, a first component containing polybutene-1, a polyolefin polymer having a melting peak temperature 20 ° C. or more higher than the melting peak temperature of polybutene-1, or a polyolefin polymer having a melting start temperature of 120 ° C. or more, and an olefin type A second component containing a thermoplastic elastomer is prepared. 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 240 to 330 ° C., the first component is melted at a spinning temperature of 200 to 300 ° C., and taken up at a take-up speed of 100 to 1500 m / min. Get the filament. Next, the stretching temperature is set to 40 ° C. or higher and lower than the melting point of the first component, and the stretching process 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 which is one form of the crimpable conjugate fiber of the present invention, the melting point temperature of the polybutene-1 contained in the second component constituting the latent crimpable conjugate fiber is 20. An olefin polymer having a melting peak temperature higher than ℃ or an olefin polymer having a melting start temperature of 120 ℃ or more is obtained from a propylene homopolymer, an ethylene-propylene copolymer, and an ethylene-butene-1-propylene terpolymer. When it is at least one selected from the group consisting of the above, the stretching temperature is preferably 40 ° C. or higher and 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. It is particularly preferably 90 ° C. or lower.

  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. 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.

  Furthermore, after crimping with the above crimper, annealing is performed in an atmosphere of dry heat, wet heat, or steam at 50 to 90 ° C., preferably 60 to 80 ° C., more preferably 60 to 75 ° C. Is preferred. Specifically, after applying the fiber treating agent, crimping is performed with a crimping machine, and the drying process is performed simultaneously with the annealing process in a dry heat atmosphere of 50 to 90 ° C., thereby simplifying the process. 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 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 and a nonwoven fabric (hereinafter also simply referred to as a nonwoven fabric).

  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. Among these, from the viewpoint of recyclability, it is preferable to use, as the mixed fiber, a single fiber made of a polyolefin resin or a composite fiber obtained by combining polyolefin resins.

  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.). 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, It is preferable to set in the range of Tm-10 (° C) to less than the melting point of the second component, preferably Tm-10 (° C) to Tm + 60 (° 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. .

  Moreover, it is preferable that the said nonwoven fabric has the compression residual distortion rate measured according to A method of JIS-K-6400-4 at 45% or less, it is more preferable that it is 35% or less, and it is 33% or less. It is particularly preferred. 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

  Further, the nonwoven fabric preferably has a repetitive compressive residual strain rate of 15% or less, more preferably 12% or less, and more preferably 11.5%, measured according to the method B of JIS-K-6400-4. It is particularly preferred that 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.

  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”, “F1”, manufactured by Tosoh Corporation. A5000 "," A2500 ", and" 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 addition, in the above, it measures by GPC (gel permeation chromatography), but when measuring by another model, it is described in 2005 plastic molding material business 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 crimping machine 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, it is possible to determine the shape of a spiral crimp and / or a wavy crimp.
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.

(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) 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)
(2) 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)
(3) PB-1 (“PB0400” manufactured by Sun Allomer, melting peak temperature (melting point): 123 ° C., MFR 190: 20 g / 10 min)
(4) LLDPE-A (“Linear low density polyethylene synthesized with KS560T metallocene catalyst” manufactured by Nippon Polyethylene Co., Ltd., melting peak temperature (melting point): 90 ° C., MFR 190: 16.5 g / 10 min, density: 0.00. 898 g / cm ³ , Q value: 2.5)
(5) LLDPE-B (“Linear low density polyethylene synthesized with 420SD metallocene catalyst” manufactured by Ube Maruzen Polyethylene Co., Ltd.), melting peak temperature (melting point): 118 ° C., MFR 190 ° C .: 7 g / 10 min, density: 0.00. 918 g / cm ³ , Q value: 3.0)
(6) LLDPE-C (“Linear low density polyethylene synthesized with KC571 metallocene catalyst” manufactured by Nippon Polyethylene Co., Ltd., melting peak temperature (melting point): 100 ° C., MFR 190: 12 g / 10 min, density: 0.907 g / cm ³ , Q value: 2.2)
(7) 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 )
(8) PPR-1 (polypropylene thermoplastic elastomer, “olefin thermoplastic elastomer synthesized by Notio 2070 metallocene catalyst” manufactured by Mitsui Chemicals, Inc., 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 )
(9) 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 )
(10) BP (butene-propylene copolymer, “5C37F” manufactured by Sun Allomer, melting peak temperature (melting point): 132 ° C., MFR230: 6 g / 10 min)

  In the above, MFR230 is the melt flow rate measured by 230 degreeC and 21.18N (2.16kgf) 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 a mixture of PP-A and PPR-1 having a mass ratio of PP-A / PPR-1 = 85/15 as the second component and using only PB-1 as the first component, the above crimpability 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 = 95/5 was used as the second component, and a mass ratio of PB-1 / LLDPE-A = 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-A which is / 8 was used.

(Example 3)
As the first 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 PB-1 and LLDPE-A having a mass ratio of PB-1 / LLDPE-A = 92/8 was used. A nonwoven fabric was prepared.

Example 4
As the second component, a mixture of PP-A and PPR-1 having a mass ratio of PP-A / PPR-1 = 75/25 was used, and as the first component, the mass ratio was PB-1 / LLDPE-A = 92. 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 is / 8 was used.

(Example 5)
As the first 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 PB-1 and LLDPE-A having a mass ratio of PB-1 / LLDPE-A = 97/3 was used. A nonwoven fabric was prepared.

(Example 6)
As the first 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 PB-1 and LLDPE-A having a mass ratio of PB-1 / LLDPE-A = 95/5 was used. A nonwoven fabric was prepared.

(Example 7)
As the first 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 PB-1 and LLDPE-A having a mass ratio of PB-1 / LLDPE-A = 80/20 was used. A nonwoven fabric was prepared.

(Example 8)
As the first 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 PB-1 and LLDPE-B having a mass ratio of PB-1 / LLDPE-B = 92/8 was used. A nonwoven fabric was prepared.

Example 9
As the first 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 PB-1 and LLDPE-C having a mass ratio of PB-1 / LLDPE-C = 92/8 was used. A nonwoven fabric was prepared.

(Example 10)
As the second component, a mixture of PP-B and PPR-1 having a mass ratio of PP-B / PPR-1 = 85/15 was used, and as the first component, the mass ratio was PB-1 / LLDPE-A = 92. 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 is / 8 was used.

(Example 11)
A mixture of PP-A and PPR-2 having a mass ratio of PP-A / PPR-2 = 85/15 was used as the second component, and a mass ratio of PB-1 / LLDPE-A = 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-A which is / 8 was used.

(Example 12)
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 LDPE having a mass ratio of PB-1 / LDPE = 90/10 was used as the first component. .

(Comparative Example 1)
Example 1 except that only PP-A was used as the second component, and a mixture of PB-1 and LLDPE-A having a mass ratio of PB-1 / LLDPE-A = 92/8 was used as the first component. In the same manner as above, crimped conjugate fibers and nonwoven fabrics were produced.

(Comparative Example 2)
As the second component, a mixture of PP-A and PPR-1 having a mass ratio of PP-A / PPR-1 = 99/1 was used, and as the first component, the mass ratio was PB-1 / LDPE = 90/10. 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 LDPE was used.

(Comparative Example 3)
A mixture of PP-A and PPR-1 having a mass ratio of PP-A / PPR-1 = 70/30 was used as the second component, and a mass ratio of PB-1 / LLDPE-A = 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-A which is / 8 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 = 55/45 was used, and as the first component, the mass ratio was PB-1 / LLDPE-A = 92. 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 is / 8 was used.

(Comparative Example 5)
A mixture of PP-A and BP having a mass ratio of PP-A / BP = 85/15 is used as the second component, and a mass ratio of PB-1 / LLDPE-A = 92/8 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 mixture of PB-1 and LLDPE-A was used.

  Results of the eccentricity of the crimped conjugate fibers obtained in Examples 1 to 12, raw cotton defibration, raw cotton crimp expression and crimping after heat processing, and initial thickness of nonwoven fabric, basis weight, repeated compression The residual strain rate and compression residual strain rate are shown in Tables 1 and 2 below. In addition, the crimped conjugate fibers of Examples 2 to 6, 8, 9, and 11 are apparently crimped conjugate fibers, and the wavy crimp or the spiral crimp shown in FIG. 2A, or the wavy crimp and the spiral crimp. Both crimps were expressed, and the number of crimps was 12-18 / 25 mm. In addition, the crimped conjugate fibers of Examples 1, 7, 10, and 12 become latent crimped conjugate fibers, exhibiting three-dimensional crimps by thermal processing when producing a nonwoven fabric, and the wavy crimp shown in FIG. 2A Crimps or spiral crimps, or both wavy and spiral crimps were expressed.

  The results of the eccentricity, raw cotton defibration, raw cotton crimp development and post-heat processing crimp development of the crimped conjugate fibers of Comparative Examples 1 to 5, and the initial thickness, basis weight, and repeated compression of the nonwoven fabric The residual strain rate and compression residual strain rate are shown in Table 3 below.

  From the results of Tables 1 to 3, the crimped conjugate fibers of Examples 1 to 12 in which the second component contains a polyolefin-based polymer and an olefin-based thermoplastic elastomer are excellent in spinnability. It can be seen that the nonwoven fabric using 1 to 12 crimped conjugate fibers has a stable resistance to repeated compression residual strain and compression residual strain. In particular, the nonwoven fabrics of Examples 2 to 6 and Examples 9 to 12 have a repeated compression residual strain ratio of 11.5% or less and a compression residual strain ratio of 33% or less, and the second component is an olefin-based thermoplastic. Compared with the nonwoven fabric of Comparative Example 1 using a crimpable conjugate fiber that does not contain an elastomer, the durability against repeated applied load, which was a problem of a conventional crimpable conjugate fiber consisting only of a polyolefin resin, is improved. It can be seen that the distortion rate after compression also decreases.

  In addition, from the comparison between Examples and Comparative Examples 3 and 4, when the content of the olefinic thermoplastic elastomer in the second component is 3 to 25% by mass, the crimped conjugate fiber is not affected without affecting the spinnability. Thus, it can be seen that a nonwoven fabric excellent in resistance to repeated compression residual strain and compression residual strain can be easily obtained. In addition, when content of the olefin type thermoplastic elastomer in a 2nd component will be 30 mass% or more, it turns out that it is inferior to the spinnability and crimp expression of a crimpable conjugate fiber, and is not preferable.

  The nonwoven fabric using the crimped conjugate fiber of the present invention is excellent in both initial bulk and bulk recoverability, hard cotton such as cushioning material, hygiene materials, packaging materials, cosmetic materials, female bra pads, It is preferably used for low density non-woven products such as shoulder pads. In addition, since the resin components that make up the composite fiber are all made of polyolefin-based resins, they are used as the above-mentioned hard cotton, stuffed cotton, and low-density nonwoven fabric products, and then recovered as raw materials consisting of polyolefin-based resins, resin raw materials It can be easily reused as a polyolefin fiber and can be reused as a polyolefin-based fiber, and is preferably used in various fiber aggregate products that require fractional collection after use and reuse of raw materials.

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

Claims (7)

A composite fiber comprising a first component and a second component,
The first component includes polybutene-1;
The second component includes a polyolefin polymer having a melting peak temperature 20 ° C. or more higher than the melting peak temperature of polybutene-1 or a polyolefin polymer having a melting start temperature of 120 ° C. or more, and an olefin thermoplastic elastomer. ,
The content of the olefinic thermoplastic elastomer in the second component is 3 to 25% by mass,
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 olefin-based thermoplastic elastomer has a density of 0.8 to 1.0 g / cm ³ , and has a Shore hardness of 50 to 100 measured using a type A durometer according to ASTM-D2240. Or the crimpable conjugate fiber of 2.   The olefin polymer having a melting peak temperature higher than the melting peak temperature of the polybutene-1 contained in the second component by 20 ° C. or higher, or the olefin polymer having a melting start temperature of 120 ° C. or higher is a propylene homopolymer, ethylene The crimped conjugate fiber according to any one of claims 1 to 3, which is at least one selected from the group consisting of a propylene copolymer and an ethylene-butene-1-propylene terpolymer.   The polybutene-1 contained in the first component has a melting peak temperature determined from DSC measured according to JIS-K-7121 of 115 to 130 ° C., and a melt flow measured according to JIS-K-7210. The crimped conjugate fiber according to any one of claims 1 to 4, wherein the rate (MFR; measurement temperature 190 ° C, load 21.18 N (2.16 kgf)) is in the range of 1 to 30 g / 10 minutes. The first component includes polybutene-1 and a copolymer of an olefin polymer different from polybutene-1 or an olefin having a polar group,
The content of the polybutene-1 is 60 to 98% by mass, and the content of an olefin polymer different from the polybutene-1 or a copolymer with a olefin having a polar group is 40 to 2% by mass. The crimpable conjugate fiber according to any one of 1 to 5. 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;
The second component includes a polyolefin polymer having a melting peak temperature 20 ° C. or more higher than the melting peak temperature of polybutene-1 or a polyolefin polymer having a melting start temperature of 120 ° C. or more, and an olefin thermoplastic elastomer. ,
The content of the olefinic thermoplastic elastomer in the second component is 3 to 25% by mass,
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.

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