JP6635739B2 - Core-sheath type composite fiber, fiber structure and method for producing the same - Google Patents

Description

  The present invention relates to a core-in-sheath type composite fiber in which a core component is polyester and a sheath component is polypropylene, a fiber structure using the same, and a method for producing the same.

  Conventionally, composite fibers using polyester as a core component and polypropylene as a sheath component have been known. Patent Literature 1 proposes disposing a resin in which polyester and polyester are mixed in a core portion and polyester in a sheath portion. Patent Document 2 proposes that polyester is disposed in a core portion and polypropylene is disposed in a sheath portion, and the volume ratio between the core portion and the sheath portion is 1/4 to 1/10. The present applicants have proposed a core-sheath type composite fiber in which a polypropylene is disposed in a core portion and a disperse dye-dyeable modified polyester is disposed in a sheath portion in Patent Document 3.

JP 2008-261070 A WO2011 / 155524 JP 2012-193483 A

  However, the conventional core-sheath type conjugate fiber has a problem that the fiber is easily broken due to friction generated during spinning or use, or so-called fibrillation is apt to occur. When fibrillation occurs, the polyester component on the surface of the dyed fiber is cracked, and the undyed polypropylene component inside the fiber is exposed to the outside.When dyeing a dark color such as black, the textile product gradually whitens. In addition to the deterioration in appearance, there is a problem that pilling occurs due to entanglement of fine fibers generated by fibrillation, that is, so-called pilling tends to occur. This problem is the same in Patent Document 1 in which a resin in which polypropylene and polyester are mixed is disposed in a sheath portion. This is because both polymers are incompatible. Further, Patent Document 2 in which the sheath portion is thickened has a problem that it is difficult to dye deeply because polypropylene is not essentially dyed. Further, in Patent Document 3 in which polyester is disposed in the sheath, in addition to the problem that pilling is liable to occur due to the fibrillation, there is a problem that, depending on manufacturing conditions, sticking of fibers easily occurs.

  The present invention solves the above-mentioned conventional problems, and has a core-sheath type composite fiber having anti-pilling properties, hardly causing agglomeration between fibers, high dyeability, high strength and high productivity, and a fiber structure using the same. An object and a method for manufacturing the same are provided.

Core-sheath composite fibers of the present invention is a core-sheath composite fiber comprising a core component and a sheath component, the core component is included as adipic acid copolymer component also small, melting point of 180 ° C. to 250 ° C. is below the glass transition temperature of 70 ° C. or less 40 ° C. or higher ethylene terephthalate - an adipate copolymer, wherein the sheath component is polypropylene, a propylene content of 50 mass% or more random copolymer, a propylene-containing An amount of 50% by mass or more of a block copolymer or a mixture thereof , wherein the sheath component is 25% by mass or more and 65% by mass or less when the core-sheath type conjugate fiber is 100% by mass. And
The method for producing a core-in-sheath type conjugate fiber of the present invention is the method for producing a core-in-sheath type conjugate fiber, wherein the core component contains at least adipic acid as a copolymer component, and has a melting point of 180 ° C. or more and 250 ° C. Below, an ethylene terephthalate-adipate copolymer having a glass transition temperature of 40 ° C. or more and 70 ° C. or less, a sheath component of polypropylene, a random copolymer having a propylene content of 50% by mass or more, and a propylene content of 50% by mass. % Or more of the block copolymer or a mixture thereof, and when the core-in-sheath type conjugate fiber is 100% by mass, the sheath component becomes from 25% by mass to 65% by mass from the composite spinneret to the core-sheath. The unstretched yarn is melt-spun in a state, and the unstretched yarn is stretched at a draw ratio of 1.3 to 4.5 times.

  The fiber structure of the present invention is a fiber structure (A) composed of the core-sheath composite fiber or a fiber structure containing the core-sheath composite fiber (A) and other fibers (B), The mixing ratio of the core-sheath type composite fiber (A) and the other fiber (B) is in the range of 10 ≦ A ≦ 100 and 0 ≦ B ≦ 90 in mass%.

  The method for producing a fiber structure according to the present invention is characterized in that the fiber structure is dyed with a disperse dye at a temperature of 110 to 130 ° C.

  In the present invention, the core component is a copolymer polyester containing at least an aliphatic dicarboxylic acid component as a copolymer component, and having a melting point of 180 ° C. or more and 250 ° C. or less. When the sheath component is 25% by mass or more and 65% by mass or less, the sheath component has anti-pilling properties, hardly causes sticking between fibers, and has high dyeability, high strength and high productivity. A core-sheath type composite fiber can be provided.

FIG. 1 is a schematic sectional view of a core-in-sheath type conjugate fiber according to one embodiment of the present invention. FIG. 2 shows that the card web made of the core-sheath type composite fiber of Example 1 was subjected to needle punching treatment, and then subjected to hydroentanglement treatment, and the resulting nonwoven fabric was dyed at 120 ° C. for 60 minutes. It is a photograph taken by observing the surface at a magnification of 200 times with a scanning electron microscope and photographing it. FIG. 3 shows that the card web made of the core-sheath composite fiber of Comparative Example 2 was subjected to needle punching treatment, and then subjected to hydroentanglement treatment. The resulting nonwoven fabric was dyed at 120 ° C. for 60 minutes. It is a photograph taken by observing the surface at a magnification of 200 times with a scanning electron microscope and photographing it. FIG. 4 shows that after dyeing the core-sheath composite fiber of Example 2 under the following conditions (120 ° C., 60 minutes), the fiber side peripheral surface was observed at an optical magnification (transmitted light) of 2000 times, It is a photograph taken. FIG. 5 shows that after dyeing the core-sheath composite fiber of Example 2 under the following conditions (120 ° C., 60 minutes), the cross section of the fiber was magnified 2000 times with an optical microscope (transmitted light), and photographed. It is a photograph.

  In the present invention, a polyester obtained by copolymerizing at least an aliphatic dicarboxylic acid component having a melting point of 180 ° C. or more and 250 ° C. or less as a core component is disposed. A polyester obtained by copolymerizing an aliphatic dicarboxylic acid component has a property of lowering the crystallinity of the polyester and increasing the toughness or toughness, and is unlikely to cause fibrillation (fracture in the length direction of the fiber). Thereby, neither the whitening phenomenon nor the pilling phenomenon occurs. In addition, since the crystallinity is lowered, the dye is easily diffused, and dark color dyeing becomes possible.

  The aliphatic dicarboxylic acid component is preferably an aliphatic dicarboxylic acid having 2 to 18 carbon atoms. More preferably, it is an aliphatic dicarboxylic acid having 2 to 10 carbon atoms. Specific examples include azelaic acid, succinic acid, adipic acid, sebacic acid and glutaric acid. More preferred is adipic acid. This is because adipic acid is also used as a raw material for nylon and its cost is low. Particularly preferred is an ethylene terephthalate-adipate copolymer obtained by copolymerizing adipic acid.

The polyester may include a repeating unit composed of an acid component and a glycol component described below.
[Acid component]
(1) 50 mol% to 90 mol% of terephthalic acid (2) 0.2 mol% to 6 mol% of sulfonic acid metal salt (3) 4 mol% to 49.8 mol% of aliphatic dicarboxylic acid [Glycol component]
(1) Ethylene glycol is 50 mol% or more and 99.9 mol% or less (2) Diethylene glycol is 0.1 mol% or more and 50 mol% or less

  As the polyester of the core component used in the present invention, those having a molecular weight used for ordinary clothing can be used. In the case of polyester, the molecular weight is usually expressed in terms of the limiting viscosity. The intrinsic viscosity is defined in JIS K 7367-5. For example, 1 g of polyethylene terephthalate is dissolved in 100 ml of a mixed solvent of phenol / 1,1,2,2-tetrachloroethane = 6/4 (mass ratio), and the solution is heated at 30 ° C. And using an Ubbelohde viscometer. An intrinsic viscosity [η] of about 0.58 to 0.70 is suitable for clothing. The weight average molecular weight is preferably about 10,000 to 100,000, more preferably about 30,000 to 800,000, and particularly preferably about 50,000 to 600,000.

  The polyester as the core component used in the present invention preferably has a glass transition temperature in the range of 40 ° C. or more and 70 ° C. or less. A more preferred lower limit of the glass transition temperature is 42 ° C. An even more preferred lower limit of the glass transition temperature is 44 ° C. A more preferred upper limit of the glass transition temperature is 68 ° C. An even more preferred upper limit of the glass transition temperature is 65 ° C. If the glass transition temperature of the polyester contained in the core component is less than 40 ° C., crystallization of the core component containing the polyester becomes difficult, and the spinnability may be reduced. When the glass transition temperature of the polyester contained in the core component exceeds 70 ° C., the crystallinity of the core component is significantly increased, the dyeability is reduced, and the texture of the fiber and the fiber structure manufactured using the fiber is hard. It may be.

  The polyester of the core component used in the present invention can be produced by a conventional polycondensation method using essentially ethylene glycol as a glycol component and essentially using terephthalic acid and an aliphatic dicarboxylic acid as an acid component. .

  In the acid component used in the polymerization of the polyester as the core component used in the present invention, the content of terephthalic acid contained in the acid component is preferably from 50 mol% to 90 mol%. More preferably, it is 84 mol% or more and 90 mol% or less. As the amount of terephthalic acid increases, the mechanical strength of the obtained polyester resin tends to increase.

  The metal sulfonic acid salt which may be copolymerized as an acid component when polymerizing the core component polyester used in the present invention is a metal salt of 5-sulfoisophthalic acid, a metal salt of 4-sulfoisophthalic acid, A metal salt of sulfophthalic acid and the like can be mentioned, and a metal salt of 5-sulfoisophthalic acid is preferable. The metal ion is preferably an alkali metal such as sodium, potassium and lithium, and an alkaline earth metal such as magnesium. The most preferred metal sulfonic acid salt is the sodium salt of 5-sulfoisophthalic acid.

  The content of the metal sulfonic acid salt contained in the acid component is preferably 0.2 mol% or more and 6 mol% or less. More preferably, it is 0.2 mol% or more and 1 mol% or less. Not only is this component relatively expensive, but if used in excess, the polyester may be water soluble and may affect the physical properties of the resulting polyester resin itself.

  The aliphatic dicarboxylic acid component unit in the acid component is at least 4 mol% and at most 49.8 mol%, preferably at least 4 mol% and at most 15 mol%. When the content of the aliphatic dicarboxylic acid component is less than 4 mol%, the glass transition temperature cannot be reduced appropriately, and as a result, the crystallinity of the core component becomes extremely high, and the dyeability is reduced. There is a possibility that the texture of the fibrous structure manufactured using the material becomes hard. On the other hand, when the content of the aliphatic dicarboxylic acid component exceeds 49.8 mol%, the glass transition temperature may be extremely lowered, and the spinnability of the fiber may be deteriorated. Note that an ester-forming derivative such as a dimethyl ester of an acid can be used instead of the dicarboxylic acid.

  It is preferable that ethylene glycol in the glycol component is 50 mol% or more and 99.9 mol% or less, and diethylene glycol is 0.1 mol% or more and 50 mol% or less. If the diethylene glycol unit exceeds 50 mol%, the single fiber strength of the fiber and the tensile strength of a spun yarn obtained using the same may be reduced. On the other hand, if it is less than 0.1 mol%, the crystallinity of the polyester tends to be high, the dyeing properties may be reduced, and the texture of the fiber and the fiber structure produced using the same may be hard. is there.

  When the core component is composed mainly of the polyester obtained by copolymerizing at least the aliphatic dicarboxylic acid component, the polyester obtained by copolymerizing the aliphatic dicarboxylic acid component has a moderately reduced crystallinity of the polyester, and therefore has a toughness or Stickiness tends to increase, and the core-sheath conjugate fiber having this polyester as a core component is less likely to be fibrillated (fission in the length direction of the fiber). Thereby, neither the whitening phenomenon nor the pilling phenomenon occurs. In addition, since the crystallinity is reduced, the dye is easily diffused, and dark color dyeing becomes possible. In particular, the acid component contains terephthalic acid in the range of 84 mol% to 90 mol%, the sulfonic acid metal salt in the range of 0.2 mol% to 1 mol%, and the aliphatic dicarboxylic acid in the range of 4 mol% or more. A glass transition in which the glycol component is in the range of 50 mol% to 99.9 mol%, and the diethylene glycol is in the range of 0.1 mol% to 50 mol%. By using an aromatic aliphatic polyester component (hereinafter also referred to as a high terephthalate polyester component) having a temperature in the range of 55 ° C. or more and 70 ° C. or less as a core component, productivity, dyeing properties, and mechanical properties when spun into a spun yarn. It is possible to obtain a core-sheath composite fiber having excellent properties.

  In the core-sheath type composite fiber of the present invention, a polyolefin is arranged as a sheath component. Polyolefins include polypropylene, polyethylene (including high-density polyethylene, low-density polyethylene, and linear low-density polyethylene), polymethylpentene, and polybutene-1, as well as copolymerization of various olefins such as ethylene, propylene, butene, and pentene. And olefin elastomers containing various olefins and polyolefins as main components. The polyolefin of the sheath component is preferably a polyolefin having a melting point of 100 ° C. to 250 ° C., more preferably at least one selected from polypropylene, polyethylene, polybutene-1 and polymethylpentene, particularly preferably polypropylene and / or polymethylpentene. Is most preferred. The polypropylene is not particularly limited, and for example, a homopolymer, a random copolymer, a block copolymer, or a mixture thereof can be used. Examples of the random copolymer and the block copolymer include a copolymer of propylene and at least one α-olefin selected from the group consisting of ethylene and α-olefins having 4 or more carbon atoms. The α-olefin having 4 or more carbon atoms is not particularly limited. For example, 1-butene, 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. The content of propylene in the copolymer is preferably 50% by mass or more. Among them, the spinnability, the stability of the spinning process, the dyeability of the resulting fiber and yarn are selected from the group consisting of propylene homopolymer, ethylene-propylene copolymer and ethylene-butene-1-propylene terpolymer. And a propylene homopolymer is more preferable.

  The sheath component polypropylene preferably has a melt flow rate (MFR) of 25 g / 10 min or more and 60 g / 10 min or less. Within this range, there is no thread breakage to the extent that actual production is possible, and stable spinning can be performed. If the melt flow rate (MFR) is less than 25 g / 10 minutes, the flowability of polypropylene at the time of melting is low, and yarn breakage tends to increase. On the other hand, if the melt flow rate (MFR) exceeds 60 g / 10 minutes, the viscosity of the polypropylene at the time of melting is lost, and yarn breakage tends to occur. The melt flow rate (MFR) is measured at 230 ° C. and 21.2 N according to JIS K7210.

  The reason why the polyester of the core component dyes even when polypropylene is present in the sheath component is thought to be that the disperse dye permeates through the polypropylene and diffuses into the polyester. In addition, the presence of polypropylene in the sheath component makes it difficult for the fibers to adhere to each other.

  The polypropylene is preferably a copolymer containing a copolymerizable component in a range of less than 50 mol%, including a homopolymer of polypropylene and an ethylene-propylene copolymer. The proportion of the polypropylene resin contained in the polypropylene component is preferably 70% by mass or more, more preferably 90% by mass or more, and particularly preferably substantially consists of only the polypropylene resin. A preferred upper limit is 100% by mass. Here, the term "substantially" means that the resin provided as a product usually contains additives such as stabilizers, and / or various additives are added during the production of fibers, so that only polypropylene resin is used. , And is used in consideration of the fact that a fiber in a form containing no other components cannot be obtained. Usually, the content of additives is at most 15% by weight.

  The polypropylene component may contain other polyolefin resin components in a range of less than 30% by mass, preferably in a range of less than 10% by mass. Other polyolefin resin components are, for example, polyethylene, polybutene, polymethylpentene and the like. The polypropylene may be composed of two or more different polypropylenes. For example, by mixing two or more polypropylenes, a polypropylene having a melt flow rate (MFR) range of the present invention can be obtained.

  As for the composite ratio (core-sheath ratio) of the core component and the sheath component, the core component is preferably 35 to 75% by mass and the sheath component is preferably 25 to 65% by mass, when the core-sheath type conjugate fiber is 100% by mass. When the content is in this range, the core-sheath type composite fiber obtained is less likely to cause separation of the core component and the sheath component, and the core-sheath type composite fiber has good dyeing properties and coloring properties. In addition, the fiber structure using the core-in-sheath type conjugate fiber has a quick drying property and a high heat retaining property. The compounding ratio (core-sheath ratio) of the core component and the sheath component is more preferably 40 to 70:60 to 30% by mass, and more preferably 40 to 70:60 to 30% by mass. The ratio is particularly preferably 60:60 to 40, and most preferably 42 to 48:52 to 58. The specific gravity of the polypropylene is 0.90 to 0.91, the specific gravity of the polyester is 1.3 to 1.4 (measured by ASTM D792), and the specific gravity of the core-sheath type composite fiber can be reduced within the above range, Furthermore, a core-sheath type composite fiber that can be dyed can be obtained.

  The composite ratio (core / sheath ratio) of the core component and the sheath component is preferably core / sheath = 67/33 to 27/73 in volume ratio. When the composite ratio is 67/33 to 27/73 (volume ratio), the above-described effects are easily obtained. The composite ratio (core / sheath) of the core component and the sheath component is more preferably 61/39 to 31/69 (volume ratio), particularly preferably 50/50 to 31/69 (volume ratio), and 38/62 to 33 /. 67 (volume ratio) is most preferred. The core-in-sheath type conjugate fiber of the present invention is not particularly limited in the shape of the fiber cross section, and has a shape other than a circle, for example, three elliptical shapes, Y shapes, X shapes, well shapes, polygons, stars, and convex portions. It may be an irregular shape such as a multi-leaf shape having up to 32 fibers, and may be a so-called hollow fiber having these shapes and having a hollow portion continuous in the length direction in a part of the fiber cross section.

  The method for producing the core-sheath type conjugate fiber of the present invention comprises the steps of: melt-spinning the core component and the sheath component in a core-sheath state from a composite spinneret into an undrawn yarn; It is preferable to perform a stretching treatment in order to adjust the temperature, and then perform a tension heat setting or a relaxation heat setting (hereinafter, these steps and processing are simply referred to as a heat setting) as necessary. In the method for producing the core-sheath type conjugate fiber of the present invention, the stretching treatment can be performed by a known stretching method. As an example, wet stretching performed in a warm water bath, a metal roll heated in dry air or heated. Stretching methods such as dry stretching performed using the same and steam stretching performed in a superheated steam atmosphere heated to a temperature of 100 ° C. or higher. Among them, in producing the core-sheath type conjugate fiber of the present invention, it is preferable to perform wet stretching in a warm water bath at 40 to 100 ° C, preferably in a warm water bath at 50 to 90 ° C. Under the above conditions, not only the undrawn yarn can be sufficiently drawn, but also the peeling of the core component and the sheath component does not easily occur, and the hydrolysis of the polyester component can be prevented. The stretching ratio is preferably about 1.3 to 4.5 times. It is more preferably 1.5 to 3.8 times, and still more preferably 1.8 to 3.5 times. This is also to prevent the core component and the sheath component from peeling off. A preferred production process is a process of stretching and, if necessary, drying after passing through steps such as heat setting, application of a crimp using a crimper, and application of a fiber treatment agent to the fiber surface. Drying is performed at a temperature of 90 to 120 ° C., more preferably at a temperature of 105 to 115 ° C., for about 15 minutes using a dryer. In order to make the core-sheath type conjugate fiber of the present invention into a spun yarn or a nonwoven fabric, it is stretched in a tow state, heat-set if necessary, and dried, and then cut into a predetermined fiber length to be a short fiber. . When it is to be made into a filament, it is drawn, heat-set if necessary, and wound up.

  In the method for producing the core-in-sheath type composite fiber of the present invention, a stretching heat setting or a relaxation heat setting may be performed after stretching, if necessary. By this heat setting, it is possible to prevent contraction and relaxation from occurring in a later step, and when producing a spun yarn using this core-sheath type composite fiber, it is possible to improve the processability in the spinning step. it can. The heat setting after the stretching can be performed by a known method, and examples include heat setting using hot water, a heated metal roll, dry air, or heated steam. When manufacturing the core-sheath type composite fiber of the present invention, the heat setting is preferably performed in a hot water bath at 70 to 100 ° C or a dryer adjusted to a temperature of 100 to 115 ° C. When performing the heat setting in a hot water bath at 70 to 100 ° C., it is preferable to perform the heat setting immediately after the stretching step because the manufacturing process can be simplified. The time for performing the heat setting varies depending on the temperature at which the treatment is performed, but is preferably about 10 seconds to 30 minutes. When producing the core-sheath type composite fiber of the present invention, the heat setting may be performed only once (one step), or may be performed a plurality of times under the same conditions or under different conditions.

  The fiber length of the core-in-sheath type conjugate fiber of the present invention is not particularly limited, and the fiber length is cut according to the purpose of the core-in-sheath type conjugate fiber, and the range is from 1 to 110 mm. When the core-sheath type composite fiber of the present invention is used for a spun yarn, the fiber length of the core-sheath type composite fiber is preferably from 24 to 75 mm, more preferably from 28 to 65 mm, and preferably from 32 to 54 mm. Is particularly preferable, and 34 to 48 mm is most preferable. When the core-sheath type composite fiber of the present invention is used as a batting material such as a nonwoven fabric or a cushion material filled with short fibers, the fiber length is preferably 20 to 80 mm, more preferably 30 to 75 mm, and 35 to 75 mm. ~ 65 mm is particularly preferred, and 40-55 mm is most preferred.

  The core-sheath type conjugate fiber of the present invention preferably has a single fiber strength of 1.8 to 5.0 cN / dtex, more preferably 2.0 to 4 cN / dtex. When the single fiber strength is 1.8 cN / dtex or more, the fibers are hard to be cut even when subjected to an external force (for example, spinning tension) at the time of processing the fibers. Further, when the single fiber strength is 5 cN / dtex or less, a fiber having better anti-pilling property can be obtained. The single fiber strength of the core-sheath type composite fiber of the present invention is particularly preferably 2.0 to 3.5 cN / dtex, and most preferably 2.2 to 3.2 cN / dtex.

  The core-sheath type composite fiber of the present invention preferably has an elongation of 10 to 70%, more preferably 20 to 60%, and particularly preferably 25 to 50%. When the elongation is 10 to 70%, the core-sheath type conjugate fiber having a low elongation is obtained as long as the texture of the obtained fiber structure is not impaired, and the processability and productivity in the spinning process are easily improved.

  The preferred single fiber fineness of the core-sheath conjugate fiber of the present invention is 0.4 to 20 dtex. By taking advantage of the characteristics of the obtained core-sheath conjugate short fibers in this fineness range, various fiber structures, for example, woven or knitted using spun yarn containing the obtained core-sheath conjugate fibers, or obtained. Various batting materials can be formed using the core-sheath composite fiber, or various nonwoven fabrics containing the core-sheath composite fiber can be obtained. In particular, a woven or knitted fabric produced using a spun yarn containing the core-sheath type conjugate fiber of the present invention satisfying the fineness range described above becomes flexible and is suitable for clothing and the like. The fineness range suitable for a spun yarn containing the core-sheath type composite fiber of the present invention and a woven or knitted fabric using the same is more preferably 0.4 to 3.5 dtex, and particularly preferably 0.6 to 2.5 dtex. , 0.8 to 2.0 dtex.

  Next, the fiber structure of the present invention will be described. The fiber structure of the present invention is a fiber structure composed of a core-in-sheath composite fiber or a fiber structure containing the core-in-sheath composite fiber (A) and another fiber (B), wherein the core-in-sheath composite fiber is The mixing ratio of (A) and other fibers (B) is in the range of 10 ≦ A ≦ 100 and 0 ≦ B ≦ 90 in mass%. Within this range, the features of the core-sheath conjugate fiber of the present invention can be utilized. Other fibers are acrylic fiber, polyester fiber, polyolefin fiber, nylon fiber, acetate fiber, acrylate fiber, ethylene vinyl alcohol fiber, urethane fiber, silk fiber, wool fiber, cashmere fiber, cotton fiber, hemp fiber, rayon fiber or Cupra fibers and the like are mentioned as an example. These fibers can be used in combination or mixed. Examples of the fiber structure of the present invention include a yarn, a woven fabric, a knitted fabric, a nonwoven fabric, a wadding, and a fiber product.

  The yarn as an example of the fiber structure can be manufactured by any method such as a ring method, an open end method, a bundling method, an alternate twisting method, a wrapping method, a vortex method (MVS method), or a non-twisting method. The preferred count in this case is an English cotton count in the range of 5 to 100S. A single yarn may be used, or a plurality of strands may be used. When the fibrous structure is a spun yarn, the fineness of the core-sheath composite fiber is preferably 0.4 dtex or more and 3.5 dtex or less, and the fiber length is preferably 24 mm or more and 75 mm or less. Within the above range, a spun yarn can be easily produced.

  The yarn preferably contains the core-sheath conjugate fiber of the present invention in an amount of 10% by mass or more. More preferably, it contains 20% by mass of the core-in-sheath conjugate fiber of the present invention, and still more preferably contains 50% by mass of the core-in-sheath conjugate fiber of the present invention. A preferred upper limit is 100% by mass. A yarn containing 10% by mass or more of the core-in-sheath type conjugate fiber of the present invention is excellent in heat retention, quick drying, and lightness.

  The yarn may contain, in addition to the core-sheath composite fiber of the present invention, other fibers in a range of 90% by mass or less, preferably in a range of 80% by mass or less, more preferably in a range of 50% by mass or less. For example, when a fiber having a relatively low single fiber strength is used as the core-sheath type conjugate fiber of the present invention, it is preferable to blend with other fibers in order to increase the strength of the entire yarn. The other fibers are not particularly limited, but may be the fibers listed as the other fibers (B) described above, and among them, acrylic fibers or polyester fibers are preferable. Acrylic fibers and polyester fibers are excellent in dyeability, washing fastness, and strength, and thus impart strength to the yarn without impairing the characteristics of the core-sheath composite fiber of the present invention.

  The number of fibers constituting the yarn is preferably 90 or more, and more preferably 100 or more. A preferred upper limit is 500. If the number of fibers constituting the yarn is 90 or more, it is difficult to break the yarn in the spinning step and the winding step.

  When the fibrous structure is a knitted fabric, the structure, the basis weight, the density, and the like are not particularly limited, and may be any of a flat knit, a rubber knit, a double-sided knit, or the like. Further, the fiber structure may be a woven fabric.

The following method can be adopted for the combination or mixing with other fibers, for example.
(1) Blending: Blending is the mixing of two or more fibers in the cotton stage. For example, mixing with mixed cotton, card, drawing, sliver, or the like. Used mainly for uniform mixing of yarn and non-woven fabric.
(2) Yarn: Yarn is a mixture in which two or more types of yarns are twisted. For example, in the case of a twin yarn, it is a mixture in which the fiber yarn of the present invention and another fiber yarn are twisted. It is used for twisting spun yarns, spun yarn and filament yarn, and filament yarns.
(3) Mixed fiber: Mixed fiber is used when fibers of filament yarns are mixed.
(4) Cross weaving: Cross weaving is a mixture in which a plurality of types of yarns constituting a woven fabric are used to form a woven fabric. For example, the warp and the weft may be of different types, or a plurality of types of the warp and the weft may be used.
(5) Cross knitting: Cross knitting is a mixture in the case of using a plurality of types of yarns when manufacturing a knit.
(6) A plurality of laminated fiber layers are mixed by needle punching and hydroentanglement in the production of nonwoven fabric.

  When the fibrous structure is a woven or knitted fabric, the fibrous structure is preferably a woven or knitted fabric containing 10% by mass or more of the yarn containing the core-sheath composite fiber of the present invention. More preferably, it contains 20% by mass or more of the yarn containing the core-in-sheath type conjugate fiber of the present invention, and still more preferably contains 30% by mass or more of the yarn containing the core-in-sheath type conjugate fiber of the present invention. A preferred upper limit is 100% by mass. Such a woven or knitted fabric is excellent in dyeability, heat retention, quick drying, and lightness.

  The woven or knitted fabric preferably comprises a yarn containing the core-sheath conjugate fiber of the present invention and a yarn of another fiber. In this case, the woven or knitted fabric may contain other fibers in a range of 90% by mass or less, preferably in a range of 80% by mass or less, and more preferably in a range of 70% by mass or less. Other fiber forms may be any form such as yarn, monofilament yarn, multifilament yarn, and the like. The other fibers may be the fibers mentioned in the above-mentioned other fibers (B), and among them, polyester fibers or urethane fibers are preferred. Polyester fibers are excellent in dyeability, washing fastness, and strength, and thus impart strength to the yarn without impairing the characteristics of the fibers of the present invention. In addition, since the urethane fiber is excellent in elasticity and shrinks slowly, a woven or knitted fabric having a stretch property can be obtained while utilizing the soft texture of the fiber of the present invention.

  The textile structure of the present invention also includes textile products such as clothes, bedding side blankets, blankets, throws or carpets. Examples of clothing include underwear, underwear, shirts, jumpers, sweaters, pants, training wear, tights, belly bands, scarves, hats, gloves, socks, ear covers, and the like. It is also suitable for winter clothing, sportswear, wadding for clothing, and the like. Further, the surface of the fabric may be raised like a fleece.

  In the method for producing a fiber structure according to the present invention, the fiber structure is dyed with a disperse dye at a temperature of 110 to 130 ° C. This makes it possible to obtain a dyed product dyed in a deep color.

  The drawings will be described below. FIG. 1 is a schematic sectional view of a core-in-sheath type conjugate fiber according to one embodiment of the present invention. The core-sheath composite fiber 1 is composed of a polyester core component 2 and a polypropylene sheath component 3. Although the core component (polyester) 2 is dyed and the sheath component (polypropylene) 3 is not dyed, the core-sheath composite fiber 1 appears to be dyed as a whole.

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not limited to a following example.

The measuring methods used in the examples and comparative examples are as follows.
<Melt flow rate (MFR)>
It measured at 230 degreeC and 21.2N according to JISK7210.
<Intrinsic viscosity>
According to JIS K 7367-5, 1 g of polyester is dissolved in 100 ml of a mixed solvent of phenol / 1,1,2,2-tetrachloroethane = 6/4 (mass ratio) and measured at 30 ° C. using an Ubbelohde viscometer. did.
<Single fiber strength and elongation at break>
According to JIS L 1015, the load value and elongation at the time of fiber cutting were measured using a tensile tester with a sample gripping distance of 20 mm, and the results were defined as single fiber strength and fiber elongation, respectively.
<Number of crimps and crimp rate>
It was measured according to JIS L 1015.
<Washing durability and color fastness>
In order to evaluate the dyeability of the obtained core-sheath type conjugate fiber and the color fastness, the dyed hydroentangled nonwoven fabric obtained by the method described below is subjected to a washing treatment, and the washing durability of the core-sheath type conjugate fiber is evaluated. And the color fastness was evaluated.
Washing is performed on the dyed hydroentangled nonwoven fabric by a washing test according to the household washing method 103 defined in JIS L 0217. First, a sample cut into a size of 30 cm in length and 21 cm in width using a dyed hydroentangled nonwoven fabric is prepared. The mass of the prepared specimen is measured, and a load cloth is prepared so that the sum of the weight of the specimen and the weight of the specimen becomes 1 kg. The prepared test piece and load cloth are put into a home washing machine, and washing using a JAFET standard combination detergent is performed for 25 minutes under a condition of 30 liters of water. After dehydration, wash with water for 2 minutes and dehydrate again. After washing again with water for 2 minutes, a dehydration treatment is performed for 4 minutes. After performing this process twice, the sample piece is hung and dried in the room. The surface of the dried sample was visually observed, and the color fastness was evaluated according to the following criteria.
++: Stained in a dark color, with little change in dyeing density before and after the washing process.
+: Stained to the extent that it can be used, and there is little change in dyeing concentration before and after washing.
-: The staining concentration is insufficient. In addition, discoloration has occurred in the sample after the washing process.
In addition, the surface of the hydroentangled nonwoven fabric after the washing treatment was observed with a scanning electron microscope, and the occurrence of core-sheath peeling was evaluated according to the following criteria.
+: No core-sheath separation of the core-sheath type composite fiber occurred on the surface of the nonwoven fabric, or the occurrence of core-sheath separation was slight.
-: The core-sheath type composite fiber core-sheath exfoliation clearly occurred on the surface of the non-woven fabric, and a part of the core-sheath type composite fiber generated pills.

(Examples 1 to 9, Comparative Examples 1 and 2 , except that Example 5 is a reference example )
<Polymer used>
The following polypropylene and polyester were used.
(1) PP-1 Sun Allomer Co., Ltd. product name "PLA000A", MFR: 45 g / 10 min. (2) PP-2 Nippon Polypropylene Co., Ltd. product name "SA03", MFR: 30 g / 10 min. (3) PP- 3 Product name “S105HG” manufactured by Prime Polymer Co., Ltd., MFR: 30 g / 10 minutes (4) PES-1 Product name “Apexa (registered trademark) 4027” manufactured by Dupont USA, ethylene terephthalate-adipate copolymer, melting point: 235 ° C, intrinsic viscosity [η]: 0.63 (hereinafter, this polyester resin is referred to as “PES-1”)
(5) PES-2 manufactured by DuPont USA "Apexa (registered trademark) 4024", ethylene terephthalate-adipate copolymer (hereinafter, this polyester resin is referred to as "PES-2")
(6) PTT Product name “Sorona (registered trademark)” manufactured by DuPont USA, polytrimethylene terephthalate (hereinafter, this polyester resin is referred to as “PTT”)

<Manufacture of core-sheath composite fibers>
Under the spinning conditions shown in Table 1, composite spinning was performed to obtain a core-sheath type composite fiber, which was drawn into a tow. The spinning conditions and the stretching conditions were as described below, and other than the following are summarized in Table 1.
(1) Spinning temperature: spinning temperature of polyolefin resin: 270 ° C, spinning temperature of polyester resin: 270 ° C
(2) Stretching conditions: Wet stretching 3.0 to 3.5 times in a 55 ° C warm water bath (3) Tensile heat treatment set after stretching: Both ends were held by nip rolls in a 95 ° C hot water bath In this state, the tow was passed through a hot water bath at a stretching ratio of 1.1, and tension heat setting was performed on the tow.
(4) Application of crimp: Application of crimp by mechanical compression using a crimper (5) Drying: hot air drying at 110 ° C. for 15 minutes (6) Tow state (state of continuous fiber bundle) from stretching to drying step And then cut to a length of 38 mm.

<Dyeability evaluation>
The obtained core-sheath type conjugate fiber was dyed using a disperse dye, and the dyeability was evaluated. The dyeability was evaluated by preparing a hydroentangled nonwoven fabric using the core-sheath composite fibers obtained as described below and dyeing the same.
(1) The obtained core-sheath conjugate fibers of Examples 1 to 9 and Comparative Examples 1 and 2 were put into a parallel card machine, and a card web composed of these core-sheath conjugate fibers having a basis weight of 100 g / m ² was prepared. I do.
(2) The card web is subjected to a needle punching process, and both surfaces are subjected to a hydroentanglement process, and dried to obtain a hydroentangled nonwoven fabric.
(3) Disperse dye (Kayalon (registered trademark) Polyester Black, manufactured by Nippon Kayaku Co., Ltd.): 8% owf (owf is an abbreviation of on the weight of fiber), dyeing aid: 2 g / L , Acetic acid: 0.5 cc / L, bath ratio 1:15, and dyeing at 120 ° C for 1 hour.
(4) The nonwoven fabric dyed under the above dyeing conditions was subjected to reduction cleaning. Reduction washing was performed so that hydrosulfite (sodium dithionite): 2 g / L, sodium hydroxide (38Be): 4.5 cc / L, soaping agent: 2.5 g / L, and the bath ratio was 1:15. Adjust and wash at 80 ° C. for 20 minutes.
(5) After the completion of the reduction cleaning, the substrate was sufficiently washed with water and dried.
(6) The dyed hydroentangled nonwoven fabric was evaluated for dyeing concentration and core-sheath peeling by the above-described procedure.

  When the core-sheath type composite fibers of Examples 1 to 9 and the core-sheath type composite fibers of Comparative Examples 1 and 2 are compared, each of the core-sheath type composite fibers of Examples 1 to 9 shows good dyeing fastness. It can be seen that a clear dark color is exhibited even after the washing test. In particular, the core-sheath type composite fibers of Examples 1 to 8 did not undergo significant fading even after the washing test. This is because the core-in-sheath type composite fibers of Examples 1 to 9 had 65% by mass or less of the total core-in-sheath type composite fibers in spite of the fact that the fiber surface was a non-dyeable polypropylene resin. The component, that is, the polypropylene covering the surface of the core-sheath type composite fiber becomes a thin film, and because the thickness of the polypropylene is thin, the disperse dye penetrates and permeates and dyes the highly dyeable polyester resin of the core component. It is presumed. In order to support this, in FIG. 4 photographed from the side peripheral surface of the core-sheath composite fiber and FIG. 5 photographing the fiber cross section of the core-sheath composite fiber, a portion near the outside of the core-sheath composite fiber, that is, polypropylene was used. Although the formed portion is not dyed, it can be confirmed that the central portion of the core-sheath type composite fiber, that is, the portion formed of polyester is dyed dark.

  On the other hand, although the core-sheath type composite fiber of Comparative Example 1 was subjected to the dyeing treatment, the dyeing concentration was thinner than that of the core-sheath type composite fiber of Examples 1 to 9, and it was difficult to use as a dark colored clothing. Was something. This is because the ratio of the polypropylene in the core-sheath type composite fiber of Comparative Example 1 was more than 65% by mass, so that the sheath component was too thick, and the ratio of the polyester was less than 35% by mass. Although the polyester itself is dyed in a dark color, it is considered that the core-sheath type composite fiber as a whole has a lighter color and is not dyed in a dark color. On the other hand, the core-sheath type composite fiber of Comparative Example 2 showed a clear dark color even after the washing treatment, and showed a high color fastness. Core-sheath peeling and fibrillation of the core component and the sheath component were caused. In this core-sheath composite fiber, the ratio of the polypropylene resin constituting the sheath component is less than 25% by mass with respect to the core-sheath composite fiber, so that the thickness of the polypropylene resin, that is, the sheath component is extremely thin. Become. As a result, the disperse dye easily permeates the sheath component of the core-sheath composite fiber. As a result, the dyeable resin present inside the core-sheath type composite fiber is easily dyed, but the sheath component is easily cracked, and the core-sheath peeling and fibrillation are caused by external force applied during the washing process. This is probably due to the fact that the problem easily occurred.

2 to 5 are representative photographs of the fibers obtained in the above Examples and Comparative Examples.
(1) FIG. 2 shows that the card web made of the core-sheath type composite fiber of Example 1 was subjected to needle punching treatment, and then subjected to hydroentanglement treatment, and the resulting nonwoven fabric was dyed at 120 ° C. for 60 minutes. Thereafter, the surface of the nonwoven fabric was observed at a magnification of 200 times with a scanning electron microscope, and photographed. As is clear from this photograph, the fibers show no damage such as fibrillation and show a good fiber shape.
(2) FIG. 3 shows that the card web made of the core-sheath type composite fiber of Comparative Example 2 was subjected to needle punching treatment, and then subjected to hydroentanglement treatment, and the resulting nonwoven fabric was dyed at 120 ° C. for 60 minutes. Thereafter, the surface of the nonwoven fabric was observed at a magnification of 200 times with a scanning electron microscope, and photographed. It can be seen that damage such as fibrillation has occurred in the fibers.
(3) FIG. 4 shows that the core-sheath composite fiber of Example 2 was dyed under the following conditions (120 ° C., 60 minutes), and the fiber side peripheral surface was magnified 2000 times with an optical microscope (transmitted light). It is a photograph observed and photographed. The fibers did not show any damage such as fibrillation and were well dyed.
(4) FIG. 5 shows that the core-in-sheath composite fiber of Example 2 was dyed under the following conditions (120 ° C., 60 minutes), and the cross section of the fiber was magnified 2000 times with an optical microscope (transmitted light). , A photograph taken. It can be seen that the core component of the fiber is well dyed.

  The core-sheath conjugate fiber of the present invention is suitable for textiles such as clothing, side lining of bedding, blankets, throws and carpets. Examples of clothing include underwear, underwear, shirts, jumpers, sweaters, pants, training wear, tights, belly bands, scarves, hats, gloves, socks, ear covers, and the like. It is also suitable for winter clothing, sportswear, wadding for clothing, and the like. Further, the surface of the fabric may be raised like a fleece.

1 core-sheath type composite fiber 2 core component (polyester)
3 sheath component (polypropylene)

Claims (11)

A core-sheath type composite fiber containing a core component and a sheath component,
The core components are included as adipic acid copolymer component also small, melting point of 250 ° C. or less under 180 ° C. or higher, a glass transition temperature of 40 ° C. or higher 70 ° C. or less ethylene terephthalate - at adipate copolymer Yes,
The sheath component is polypropylene, a random copolymer having a propylene content of 50% by mass or more, a block copolymer having a propylene content of 50% by mass or more, or a mixture thereof.
The core-in-sheath type conjugate fiber, wherein the sheath component is not less than 25% by mass and not more than 65% by mass, when the core-in-sheath type conjugate fiber is 100% by mass. The core-sheath conjugate fiber according to claim 1, wherein the core-sheath conjugate fiber has a single fiber strength of 1.8 cN / dtex or more and 5.0 cN / dtex or less. The core-sheath composite fiber according to claim 1 or 2, wherein the core component of the core-sheath composite fiber is dyed with a disperse dye, and the sheath component is not dyed. The core / sheath type composite fiber according to any one of claims 1 to 3, wherein a volume ratio of the core component and the sheath component of the core / sheath type composite fiber is core / sheath = 67/33 to 27/73. A core-sheath conjugate fiber for a spun yarn, wherein the fiber length of the core-sheath conjugate fiber according to any one of claims 1 to 4 is 24 to 75 mm. A method for producing a core-in-sheath type conjugate fiber according to any one of claims 1 to 4,
The core component is an ethylene terephthalate-adipate copolymer having at least adipic acid as a copolymer component, a melting point of 180 ° C to 250 ° C, and a glass transition temperature of 40 ° C to 70 ° C, and a sheath component. A polypropylene, a random copolymer having a propylene content of 50% by mass or more, a block copolymer having a propylene content of 50% by mass or more, or a mixture thereof;
When the core-sheath type conjugate fiber is 100% by mass, the sheath component is melt-spun in a core-sheath state from a composite spinneret so as to be 25% by mass or more and 65% by mass or less to form an undrawn yarn.
A method for producing a core-in-sheath type conjugate fiber, wherein the undrawn yarn is subjected to a drawing treatment at a draw ratio of 1.3 to 4.5 times. The method for producing a core-sheath type composite fiber according to claim 6, wherein heat setting is performed in a hot water bath at 70 to 100 ° C after the drawing treatment. A fiber structure (A) comprising the core-in-sheath composite fiber according to any one of claims 1 to 4, or a fiber structure comprising the core-in-sheath composite fiber (A) and another fiber (B). hand,
A fiber structure, characterized in that the mixing ratio of the core-sheath type composite fiber (A) and the other fiber (B) is in the range of 10 ≦ A ≦ 100 and 0 ≦ B ≦ 90 in mass%. The fiber structure according to claim 8 , wherein the fiber structure is at least one selected from a yarn, a woven fabric, a knitted fabric, a nonwoven fabric, a wadding, and a fiber product. The fiber structure according to claim 8 or 9 , wherein the fiber structure is a spun yarn, and the fineness of the core-sheath composite fiber constituting the spun yarn is 0.4 dtex or more and 3.5 dtex or less, and the fiber length is 24 mm or more and 75 mm or less. Fiber structure. It is a manufacturing method of the fiber structure according to any one of claims 8 to 10 ,
A method for producing a fiber structure, comprising dyeing the fiber structure with a disperse dye at a temperature of 110 to 130 ° C.