JP6356976B2 - Sea-island type composite fiber - Google Patents

Description

  The present invention relates to a sea-island type composite fiber using a polymethylpentene resin and a thermoplastic resin and having excellent dyeability, water repellency, and heat resistance.

Polyolefin fibers are widely used in industrial applications because they are excellent in light weight and water repellency. Among them, polypropylene fibers are often used. However, since polypropylene fibers are difficult to be dyed with dyes, it is difficult to apply them to clothing applications.
In order to improve dyeability, Patent Document 1 proposes a polyester composite fiber that can be dyed with a disperse dye as a core component and a polypropylene composite fiber in which a polypropylene resin is arranged as a sheath component. It is described that by using such a structure, the fiber can be dyed in a dark color, and a polypropylene fiber having good light fastness and chlorine fastness can be obtained.
On the other hand, fibers made of polyolefin resins and thermoplastic resins such as polyester resins and polyamide resins have low compatibility, so that they are easy to peel off at the resin bonding surface, resulting in poor yarn-making stability and dyeability and difficult to handle. There was a problem.
Therefore, in Patent Document 2, a polypropylene resin is disposed as the core component, and a polyester resin is disposed as the sheath component, so that the melt flow rate (MFR) of the polypropylene resin exceeds 28 g / min and is less than 60 g / min. Therefore, it is described that a core-sheath type composite fiber that can be stably spun without yarn breakage and has good dyeability can be obtained. Further, this document describes that the core component and the sheath component are prevented from being peeled off under a mild stretching condition such as wet heat stretching in a relatively low temperature hot water bath.
In addition, the woven or knitted fabric is usually subjected to a dry heat treatment such as a preset or final set. Fibers using polypropylene resin have a lower melting point than fibers using polyester resin or polyamide resin, and fusion occurs during dry heat treatment. For this reason, it has been difficult to use polypropylene fiber in combination with polyester fiber, nylon fiber, or the like.
Therefore, Patent Document 3 describes a split type composite fiber using polymethylpentene as one component in order to obtain an ultrafine fiber having excellent heat resistance and chemical resistance.

JP 2008-261070 A JP 2012-193484 A JP 2000-017524 A

However, although the fiber described in Patent Document 1 can be dyed, core-sheath peeling is likely to occur, so that there is a problem in the yarn production stability and color spots are likely to occur.
Moreover, although patent document 2 describes that it is made hard to produce core-sheath peeling of a fiber by setting it as mild extending | stretching conditions, such as performing wet heat processing at low temperature, productivity is high on such conditions. Low and high cost.
On the other hand, although Patent Document 3 describes that a fiber having excellent heat resistance with a melting point of 220 ° C. or higher is obtained, this fiber is a split type whose main use is an industrial filter. It is a composite fiber and does not describe dyeability and peel resistance, which are important when used for clothing.
Therefore, the present invention is a composite fiber composed of a polyolefin resin and a dyeable thermoplastic resin, and without taking a special stretching method, the peel resistance, the yarn production stability and the heat resistance are good and there are few dyeing spots. The object is to obtain a polyolefin composite fiber.

That is, the gist of the present invention consists of a sea part and 3 or more and 20 or less island parts, and has a sea-island structure in which the joint surface between the sea part and the island part is continuous in the fiber length direction. ) To ( e ) are sea-island type composite fibers that satisfy the requirements.
(A) Polymethylpentene-based resin in which sea component is polymethylpentene as a main component (b) Island component is polyethylene terephthalate (c) Area ratio of sea part in fiber cross section exceeds 50% (d) In fiber cross section Minimum thickness of sea part is 1μm or more
(E) The absence fused and blown after dry heat treatment under dry heat atmosphere of 185 ° C., among them, the contact angle of a water droplet of the sea-island composite fiber is preferably 135 ° or more. The density of the sea-island type composite fiber is preferably 1.10 g / cm ³ or less, and the single yarn fineness is preferably 1 dtex or more.

  According to the sea-island type composite fiber of the present invention, it can be stretched without peeling without special measures such as stretching under low-temperature wet heat conditions, has good dyeability with disperse dyes, polyester fiber and polyamide A polyolefin fiber having good heat resistance that can be used in combination with a thermoplastic resin fiber such as a fiber can be obtained. Moreover, the effect of being excellent in the water repellency which is the characteristic of polyolefin fiber is also show | played.

FIG. 1 is an example of the cross-sectional shape of the sea-island composite fiber of the present invention. FIG. 2 is an example of a cross-sectional shape of a sea-island type composite fiber outside the scope of the present invention. FIG. 3 is an example of the cross-sectional shape of a sea-island composite fiber outside the scope of the present invention.

  In the present invention, the sea-island type composite fiber refers to a sea-island type composite fiber composed of a sea part composed of a sea component and an island part composed of an island component.

  The sea-island composite fiber of the present invention is composed of a polymethylpentene resin as a sea component and a thermoplastic resin that can be dyed with a disperse dye as an island component.

  In the sea-island composite fiber of the present invention, the sea component polymethylpentene resin refers to a resin mainly composed of polymethylpentene. Examples of the polymethylpentene include those having a repeating unit of 4-methylpentene-1. It may be a homopolymer using a single component as a repeating unit or a copolymer containing another component as a repeating unit. As a copolymer, 4-methylpentene-1, for example, ethylene, propylene, butene-1, hexene-1, octene-1, decene-1, tetradecene-1, octadecene-1, and the like are copolymerized. The thing which was done is mentioned.

  In the present invention, the melting point of the resin means a value indicated by the peak top of the endothermic peak when the temperature is raised to 300 ° C. at 10 ° C./min in a nitrogen atmosphere using a differential scanning calorimeter (DSC). .

  The melting point of the polymethylpentene is preferably 200 ° C. or higher and 250 ° C. or lower. When the melting point is lower than 200 ° C., sufficient heat resistance tends not to be obtained. When the melting point is higher than 250 ° C., in melt spinning, it tends to be difficult to combine the island component with the thermoplastic resin, and it is difficult to obtain sea-island type composite fibers. That is, in the above range, when a fiber structure is formed by mixing fibers made of a thermoplastic resin such as a polyester resin or a polyamide resin, a dry heat treatment in post-processing such as a preset or final set is usually performed ( For example, it is easy to obtain one having sufficiently good heat resistance for performing a heat treatment at 120 to 190 ° C. and a dyeing treatment (for example, a wet heat treatment at 100 to 135 ° C.). The melting point of polymethylpentene is more preferably 210 ° C. or higher and 235 ° C. or lower.

  The melt freight (MFR) at 260 ° C. and a load of 5.0 kg of the polymethylpentene is preferably 100 g / 10 min or more and 300 g / 10 min or less. That is, when the MFR is 100 g / 10 min or more, there is a tendency that an agglomeration due to the fusion of the islands is less likely to occur, and thus the sea and the islands are less likely to be separated. As a result, the spinning stability in the spinning process and the drawing process becomes good, and there is a tendency that whitening phenomenon and dyeing spots after dyeing hardly occur. Moreover, it is preferable that MFR is 300 g / 10min or less from the point which maintains the mechanical strength of a fiber favorably. Therefore, when the MFR is within the above range, the island portions hardly merge with each other, the sea portion and the island portion do not peel off, and a fiber having good mechanical strength can be easily obtained. Especially, MFR is preferably 150 g / 10 min or more, and preferably 250 g / 10 min or less. More preferably, it is 150 g / 10min or more and 200 g / 10min or less.

  The polymethylpentene-based resin may be blended with a resin other than polymethylpentene, such as an olefin resin such as a polyethylene resin or a polypropylene resin, or a polystyrene resin, as long as the heat resistance is not impaired. As a specific example, when blending polypropylene resin, it is preferable to make it 40 mass% or less. When blending in excess of 40% by mass, the yarn tends to be fused and the texture of the fabric tends to be hard when a dry heat treatment of about 185 ° C., which is usually performed as a post-treatment of polyester or polyamide, is performed. A more preferable blend ratio is 30% by mass or less, and further preferably 25% by mass or less.

  The polymethylpentene resin may be modified by adding an additive within a range not impairing the effects of the present invention. Examples of the additive include a compatibilizer, a heat stabilizer, an antioxidant, a fluorescent whitening agent, an infrared reflector, and an infrared absorber. Moreover, an additive may be used independently and may be used together.

  In the sea-island type composite fiber of the present invention, the island component is not particularly limited as long as it is a thermoplastic resin that can be dyed with a disperse dye. Specific examples include polyester resin, polyamide resin, and polyvinyl alcohol resin. Among these, a polyester resin and a polyamide resin are preferable from the viewpoint of heat resistance and mechanical characteristics, and a polyester resin is more preferable from the viewpoint of deep dyeing.

The melting point of the thermoplastic resin is preferably 180 ° C. or higher and 280 ° C. or lower.
In the present invention, the island part is covered with sea components of the sea part, and has good heat resistance without any problem even in the dry heat treatment in post-processing such as a normal preset or final set. When the melting point of the island component is too excessive low, the dry-heat treatment tends to melt easily occurs of islands. Moreover, when too high, there exists a tendency for the composite spinning with a sea component to become difficult. Therefore, the above range is preferable from the viewpoints of heat resistance, stable yarn production, and easy suppression of peeling between the sea and the island. The melting point of the thermoplastic resin is more preferably 210 ° C. or higher and 270 ° C. or lower, and further preferably 220 ° C. or higher and 265 ° C. or lower.

  The thermoplastic resin may be modified by adding an additive within a range not impairing the effects of the present invention. Examples of the additive include a compatibilizer, a heat stabilizer, an antioxidant, a fluorescent brightener, an infrared reflector, and an infrared absorber. Moreover, an additive may be used independently and may be used together.

  The polyester resin may be a linear saturated polyester produced by a polycondensation reaction using a dicarboxylic acid or its ester-forming derivative and a diol or its ester-forming derivative as raw materials. , Polyethylene naphthalate, polylactic acid and the like, but are not limited thereto. In particular, those mainly composed of polyethylene terephthalate are preferable, and may be a homopolyester or a copolyester. Examples of copolymer components include adipic acid, sebacic acid, phthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, diphenyldicarboxylic acid, 5-sodium sulfoisophthalic acid, diphenylsulfone dicarboxylic acid, p-oxyethoxybenzoic acid, etc. Those containing dicarboxylic acids or ester-forming derivative components thereof, or polyalkylene glycol components such as polyethylene glycol, polytetramethylene glycol, polyhexanemethylene glycol and the like are preferable. The polyalkylene glycol may contain a diol such as diethylene glycol, propylene glycol, neopentyl glycol, polyoxyalkylene glycol, p-xylene glycol, 1,4-cyclohexanedimethanol, or an ester-forming derivative component thereof. These copolymerization components may be used one by one, or two or more types may be used.

  Examples of the polyamide resin include, but are not limited to, single polymers or copolymers such as nylon 6, nylon 10, nylon 12, nylon 66, and the like.

  The cross-sectional shape of the sea-island composite fiber of the present invention will be described below.

  The sea-island type composite fiber of the present invention is a composite fiber having a sea-island structure in which one or more sea parts and two or more island parts are continuously formed in the length direction.

  In the sea-island type composite fiber of the present invention, sea components are exposed on the fiber surface. That is, in the fiber cross section (fiber cross section perpendicular to the fiber length direction), the sea is exposed on the outer periphery.

FIG. 1 is a diagram showing an example of a cross-sectional shape of a fiber cross section of a sea-island type composite fiber of the present invention. In this example, 19 islands b having a round cross section are arranged in the sea part a of the fiber having a round cross section so as to be close to the center of the fiber. Further, the minimum thickness of the sea portion is 1 μm or more. Here, the minimum thickness of the sea is the shortest distance between the outer periphery of the fiber and the outer periphery of the island, and when the normal of the outer periphery of the fiber (a straight line passing through one point of the outer periphery of the fiber and perpendicular to the tangent at this point) is drawn. Indicates the distance to the outer periphery of the nearest island. For example, in the sea-island type composite fiber of FIG. 1, the normal line is drawn from the point p on the outer periphery of the fiber, and the intersection point with the outer periphery of the island part b is defined as q. In the fiber cross section, the shortest length X of the line segment p-q connecting the points p and q is the minimum thickness of the sea part.
When the minimum thickness of the sea part is less than 1 μm, the sea component and the island component are easily separated in the stretching process, the weaving and knitting process, and the dyeing process. For this reason, deterioration of the yarn production stability, generation of dyeing spots, and whitening after dyeing are likely to occur.

  In the fiber cross section of the sea-island composite fiber of the present invention, the number of island portions is preferably 40 or less. If the number of islands is within 40, it is easy to stably obtain sea-island type composite fibers that are less likely to cause separation between the sea part and the island part with appropriate strength. On the other hand, when the number of islands exceeds 40, the density of the islands in the fiber increases, and the islands are easily fused to form an agglomerate during the spinning process, causing separation between the sea and the islands. It becomes easy. Further, the number of island portions to be arranged is more preferably 20 or less from the viewpoint of ensuring the formation of a more stable fiber cross section. By controlling the number of island portions to such a number, it becomes easier to suppress aggregation between the island portions. In addition, the number of island portions to be arranged is preferably 3 or more, more preferably 10 or more, from the viewpoint of preventing separation while increasing the joint area between the sea portion and the island portion.

  In the fiber cross section of the sea-island composite fiber of the present invention, the area ratio of the sea part to the entire fiber cross section is configured to exceed 50%. That is, in the fiber cross section, when the area ratio of the sea part is 50% or less, the thickness of the sea part between the island part and the island part becomes thin, the island parts are fused, and the sea part and the island part are separated. It becomes easy. Also, since the area ratio of the sea part tends to be light after dyeing, the area ratio is preferably more than 50% and not more than 90%, more preferably more than 50% and not more than 75%, more preferably Is greater than 50% and less than or equal to 65%.

  In the fiber cross section of the sea-island type composite fiber of the present invention, the area ratio of the island part to the entire fiber cross section is preferably 50% or less. The area ratio of the islands may be appropriately set in consideration of the balance between lightness and dyeability.

  In the fiber cross section of the sea-island type composite fiber of the present invention, it is preferable that the island portion is disposed in the center portion in such a range that the island portions do not merge. For example, in the fiber cross section, when the fiber radius is r, it is preferable to arrange the island portion in a range of [radius r × 0.90] or less from the fiber center point, more preferably [radius r × 0.85]. It is to arrange the island part in the following range. Thereby, the minimum thickness of the sea part is easily set to 1 μm or more, and there is a tendency to suppress the deterioration of the yarn production stability, the occurrence of dyeing spots, and the whitening phenomenon after dyeing.

  In the sea-island type composite fiber of the present invention, the total fineness is preferably 40 dtex or more and 200 dtex or less from the viewpoint of yarn production stability. More preferably, it is 40 dtex or more and 150 dtex or less, More preferably, it is 40 dtex or more and 100 dtex or less.

  In the sea-island composite fiber of the present invention, the single yarn fineness is preferably 1 dtex or more. If the single yarn fineness is less than 1 dtex, it tends to be difficult to maintain the minimum thickness of the sea at 1 μm or more, and the yarn-making stability is deteriorated, the occurrence of dyeing spots, and the whitening phenomenon after dyeing are likely to occur. Moreover, the single yarn fineness is preferably 5 dtex or less from the viewpoint of the texture when it is made into a fabric. If it exceeds 5 dtex, the texture tends to be hard when it is made into a fabric. More preferably, it is 4 dtex or less, More preferably, it is 3 dtex or less.

The density of the sea-island type composite fiber of the present invention will be described. The polymethylpentene, a sea component, is excellent in lightness with a density of about 0.83 g / cm ³ . On the other hand, in this invention, an island component consists of a thermoplastic resin which can be dye | stained with a disperse dye. Therefore, the density of the sea-island composite fiber of the present invention changes according to the area ratio of the sea part in the fiber cross section. The larger the area ratio of the sea component made of a polymethylpentene resin having a low density from the viewpoint of light weight, the better, but the area ratio of the island component made of a thermoplastic resin having a density higher than that of polymethylpentene is larger from the viewpoint of dyeability. Is preferred. Considering these balances, the density of the sea-island type composite fiber of the present invention is preferably 1.10 g / cm ³ or less. The lower limit is preferably about 0.90 g / cm ³ . When the density of the sea-island type composite fiber of the present invention is in such a range, it is easy to obtain a sea-island type composite fiber excellent in both lightness and dyeability. From this point, the area ratio of the sea part in the fiber cross section is more than 50%, preferably 85% or less, more preferably more than 50% and 65% or less.

  The water repellency of the sea-island composite fiber of the present invention will be described. The polymethylpentene, which is a sea component used in the present invention, has a very low surface tension of about 24 mN / m, and therefore has excellent water repellency among polyolefin resins. In the sea-island type composite fiber of the present invention, if the island part is exposed on the fiber surface, the water repellency is inhibited by the island part, which is not preferable. In addition, blending with other polyolefin resins increases surface tension and decreases water repellency. Water repellency can be expressed as a contact angle of a water droplet by a method described later. The contact angle of water droplets is preferably 135 ° or more, and good water repellency can be maintained even with various fiber structures.

  In the present invention, heat resistance will be described. The sea-island fiber of the present invention is preferably one that does not melt or melt during a dry heat treatment at 185 ° C. Usually, a woven or knitted fabric needs to be subjected to a dry heat treatment such as a preset or final set. In the case of a fabric using polyester fiber or polyamide fiber, heat treatment is usually performed at 120 ° C to 190 ° C. If fibers with low heat resistance are used at that time, fiber fusion or fusing will occur during dry heat treatment, resulting in a fabric with a hard texture or a hole, and used for clothing and industrial materials Can not be. From this point, the higher the heat resistance, the better, and the above state is preferable.

Various fiber structures can be obtained by using the sea-island composite fiber of the present invention. Examples of the fiber structure include yarn bundles such as twisted yarns and braids, processed yarns such as false twisted yarns and taslan processed yarns, spun yarns, various mixed yarns, fabrics such as woven and knitted fabrics and nonwoven fabrics, and stuffed cotton. be able to.
Particularly preferred is a fiber structure mixed with fibers made of a thermoplastic resin such as polyester fiber or polyamide fiber and mixed fiber or knitted or knitted fabric, and these include dyeing property, heat resistance, light weight, water repellency, etc. The target fiber structure can be obtained while effectively utilizing the features as appropriate.

  Next, the suitable example of the method of manufacturing the sea-island type composite fiber of this invention is demonstrated.

First, the sea component polymethylpentene resin and the island component thermoplastic resin are prepared.
The prepared sea component and island component are separately melted, discharged from the spinneret so as to have the above-mentioned cross-sectional shape, cooled, and then stretched to obtain the sea-island composite fiber of the present invention.

  The spinning temperature is preferably 220 ° C. or higher and 300 ° C. or lower, more preferably 250 ° C. or higher and 290 ° C. or lower, from the viewpoints of heat resistance and spinnability of the polymethylpentene resin and the thermoplastic resin. The spinning speed is preferably 800 m / min or more and 4500 m / min or less, and more preferably 1000 m / min or more and 3800 m / min or less.

  In addition, it is preferable that the sea-island type composite fiber of the present invention is joined to each other in a state where the sea part and the island part are continuous without being interrupted in the fiber length direction. In this case, the sea part and the island part are hardly separated in the drawing process, the weaving and knitting process, the dyeing process, and the like, and it is easy to suppress the deterioration of the yarn production stability and the whitening phenomenon. On the other hand, if the resin in the island portion is interrupted in the length direction of the fiber, it is not preferable because it tends to be difficult to suppress the deterioration of the yarn production stability and the whitening phenomenon after dyeing.

  The drawing temperature is preferably 90 ° C. or higher and 120 ° C. or lower, more preferably 95 ° C. or higher and 110 ° C. or lower, from the viewpoint of yarn production stability. The draw ratio is preferably about 2.0 times or more and 3.5 times or less from the viewpoint of stably obtaining the cross-sectional shape of the sea-island composite fiber.

  When producing the sea-island type composite fiber of the present invention, any method such as a method of winding once after melt spinning and then stretching, or a direct spinning stretching method of stretching without melt winding and then winding once Can be adopted.

  In this manner, the sea-island type composite fiber of the present invention can be obtained which has no peeling between the sea part and the island part and has good yarn-making stability.

  Moreover, the sea-island type composite fiber of the present invention thus obtained can be suitably dyed with a disperse dye. That is, in dyeing with a disperse dye, since the dye penetrates to the island components, it can be dyed in a dark color. On the other hand, in the case of dyeing using a cationic dye or an acid dye, since the polymethylpentene resin exhibits high water repellency, the dye does not penetrate to the thermoplastic resin of the island component and is not preferred because it is difficult to dye.

Islands-in-sea type composite fiber of the present invention obtained in this way, reeling stability is good, because heat resistance good, stretching step, false twisting process, knitting weaving process, spinning kneading step, each such dyeing process Even in the process, it is difficult to peel off, and the handleability in each process is excellent. In particular, during the dyeing, color spots are not generated and the dyeability is not deteriorated, and the whitening phenomenon does not occur. Moreover, by adjusting suitably, favorable lightweight property and water repellency can be obtained easily according to the objective.

  EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the following examples illustrate the present invention and do not limit the present invention. Various physical properties were measured and evaluated as follows.

(1) Melting point Using a differential scanning calorimeter (DSC) (“DSC 8230” manufactured by Rigaku), the temperature is raised to 300 ° C. at a temperature rising rate of 10 ° C./min in a nitrogen atmosphere, and the peak top of the endothermic peak is thermoplastic. The melting point of the resin.

(2) Yarn Stability The yarn making stability was evaluated based on the average number of yarn breakage when a 10 kg yarn was produced, and B or higher was determined to be acceptable according to the following criteria.
A: When thread breakage is less than 1 B: When thread breakage is 1 or more and less than 3 C: When thread breakage is 3 or more

(3) Confirmation of island state (fusion / peeling), fiber diameter and minimum thickness of sea part Arbitrary two parts of the obtained sea-island type composite fiber were cut perpendicular to the length direction, and the cut surface was 1500 using an electron microscope. Magnification was observed to confirm the occurrence of island fusion / peeling. Those in which these defects did not occur were evaluated as “good”. Moreover, the fiber diameter and the minimum thickness of the sea part were measured on the same cut surface.

(4) Strength / Elongation of Fiber According to JIS L1013, a tensile test using an autograph AGS manufactured by Shimadzu Corporation was performed, and the fiber was broken under the conditions of a measurement length: 200 mm and a tensile speed: 200 mm / min. The breaking strength and the breaking elongation were measured 5 times, and the average value was obtained.

(5) Lightness The density of the obtained sea-island type composite fiber was calculated by the density gradient tube method according to JIS K7112 D method. An immersion liquid prepared using a zinc chloride aqueous solution as a heavy liquid and ethanol as a light liquid was prepared in a density gradient tube, and allowed to stand for 24 hours at a constant temperature bath at 23 ° C. The sample was placed in a density gradient tube and allowed to stand for 1 hour, and then the floating state was confirmed. The lightness was evaluated based on the following criteria.
A: It has excellent light weight with a specific gravity of less than 1.0 g / cm ³ .
B: It has good light weight with a specific gravity of 1.0 g / cm ³ or more and less than 1.1 g / cm ³ .
C: The specific gravity is 1.1 g / cm ³ or more and does not have light weight.

(6) Evaluation of water repellency A cylindrical knitted fabric was prepared using the obtained sea-island type composite fiber, and 2.5 μL of water was dropped on the surface of the cylindrical knitted fabric placed horizontally, and the contact angle of water droplets was measured. The water repellency was evaluated based on the following criteria.
○: A water droplet close to a true sphere and having a contact angle of 135 ° or more.
X: A water droplet slightly deviated from the true sphere and having a contact angle of less than 135 °.

(7) Evaluation of heat resistance After the tubular knitted fabric made of the obtained sea-island type composite fiber was opened, it was fixed with a frame of 20 cm x 25 cm and subjected to dry heat treatment with hot air at 185 ° C for 2 minutes. The fabric after the dry heat treatment was observed at 1000 times with an electron microscope and evaluated according to the following criteria.
○: When there is no yarn fusion or fusing and the texture is not hard ×: When there is yarn fusion or fusing and the texture is hard

(8) a tubular knitted fabric produced in dyeability evaluation obtained sea-island type composite fiber, performs a fine mixing for 20 minutes at 70 ° C., washed with water, air dried disperse dye (Dianix ® Blue ACE) 2 0.0% o. w. f, bath ratio 1:50, after high-pressure dyeing at 130 ° C. for 1 hour, reduction washing was carried out by a conventional method and evaluated according to the following criteria.
○: When there is no color spot or whitening phenomenon △: When there is color spot but no whitening phenomenon ×: When there is whitening phenomenon

L ^* a ^* b ^* of the dyed tubular knitted fabric was measured according to JIS Z8729. A colorimetric color difference meter (“ZE 2000” manufactured by Nippon Denshoku Industries Co., Ltd.) was used for the measurement. Here, the L ^* value represents the lightness of the color from 0 to 100. The closer to 0, the darker the color, and the closer to 100, the brighter. The a ^* value represents reddish green, with positive numbers being reddish colors and negative numbers being greenish colors. b ^* represents yellowish blue, with positive numbers being yellowish colors and negative numbers being blueish colors.

[Example 1]
Polymethylpentene (“TPX (registered trademark) DX820” manufactured by Mitsui Chemicals, MFR 180 g / 10 min, melting point 233 ° C.) is used as the sea component, polyethylene terephthalate (melting point 258 ° C.) is used as the island component, and the sea: island area ratio is 56: As shown in FIG. 1, 19 island components were spun at 285 ° C. from the die arranged at the center of the fiber as shown in FIG. 1, and the undrawn yarn was wound up at 1500 m / min. Subsequently, the obtained undrawn yarn was drawn at a drawing speed of 800 m / min and a draw ratio of 2.4 times to obtain a sea-island type composite fiber of 66 dtex / 24f. The minimum thickness of the sea part in the fiber cross section of the obtained sea-island type composite fiber was 1.8 μm, and no peeling at the interface between the sea part and the island part was observed, and the yarn-making stability was good. Even after 2 minutes of dry heat treatment at 185 ° C., there was no fusion or fusing, and the heat resistance was excellent. Moreover, it dye | stained dark blue without a color spot, and the dyeability was favorable. The contact angle measured by the water repellency evaluation was 136.8 ° and had good water repellency and good lightness. The obtained results are shown in Table 1.

[Example 2]
A sea-island composite fiber was produced in the same manner as in Example 1 except that 44 dtex / 24f. The minimum thickness of the sea part in the fiber cross section of the obtained sea-island type composite fiber was 1.1 μm, and no peeling was observed at the interface between the sea part and the island part, and the yarn-making stability was good. Even after 2 minutes of dry heat treatment at 185 ° C., there was no fusion or fusing, and the heat resistance was excellent. Moreover, it dye | stained dark blue without a color spot, and the dyeability was favorable. The contact angle measured in the water repellency evaluation was 136.2 ° and had good water repellency, and the lightness was also good. The obtained results are shown in Table 1.

Example 3
A sea-island type composite fiber was produced in the same manner as in Example 1 except that a base in which seven island components were arranged was used. The minimum thickness of the sea part in the obtained sea-island type composite fiber was 1.3 μm, peeling at the interface between the sea part and the island part was not observed, and the spinning stability was good. Even after 2 minutes of dry heat treatment at 185 ° C., there was no fusion or fusing, and the heat resistance was excellent. Moreover, it dye | stained dark blue without a color spot, and the dyeability was favorable. The contact angle measured in the water repellency evaluation was 136.5 °, had good water repellency, and had good lightness. The obtained results are shown in Table 1.

Example 4
A sea-island composite fiber was produced in the same manner as in Example 1 except that a resin obtained by blending polymethylpentene resin and polypropylene (“SA01A” manufactured by Nippon Polypro Co., Ltd.) at a mass ratio of 80:20 was used as the sea component. The minimum thickness of the sea part in the obtained sea-island type composite fiber was 1.6 μm, and no peeling at the interface between the sea part and the island part was observed, and the yarn-making stability was good. Even after 2 minutes of dry heat treatment at 185 ° C., there was no fusion or fusing, and the heat resistance was excellent. Moreover, it dye | stained dark blue without a color spot, and the dyeability was favorable. The contact angle measured in the water repellency evaluation was 136.1 ° and had good water repellency and good lightness. The obtained results are shown in Table 1.

[Comparative Example 1]
A sea-island type composite fiber was produced in the same manner as in Example 1 except that a base serving as a normal core-sheath thread (single core) was used. The obtained sea-island fiber was peeled off at the interface between the core component and the sheath component. In the dyeability evaluation, color spots occurred, but no whitening phenomenon occurred. The contact angle measured by water repellency evaluation was 136.9 ° and the water repellency was good. The obtained results are shown in Table 2.

[Comparative Example 2]
A sea-island composite fiber was produced in the same manner as in Example 1 except that a base in which 19 island components were uniformly arranged over the entire fiber as shown in FIG. 2 was used. The minimum thickness of the sea part in the obtained sea-island type composite fiber was 0.3 μm or less, and a part of the island part was exposed to the surface. Further, peeling was observed at the interface between the sea part and the island part, the spinning stability was poor, and a whitening phenomenon occurred in the dyeability evaluation. There was also exposure of islands, and the contact angle measured by water repellency evaluation was 132.1 °, which was low in water repellency. The obtained results are shown in Table 2.

[Comparative Example 3]
A sea-island type composite fiber was produced in the same manner as in Example 1 except that a base having a petal shape as shown in FIG. 3 and an island component exposed to the fiber surface was used. Since the thermoplastic resin is exposed on the fiber surface, the yarn-making stability is poor, and composite fibers could not be obtained. The obtained results are shown in Table 2.

[Comparative Example 4]
A sea-island composite fiber was produced in the same manner as in Example 1 except that the sea: island area ratio was 50:50. The obtained sea-island type composite fiber was a core-sheath fiber having a single core in which island components were fused. In the staining evaluation, color spots occurred, but no whitening phenomenon occurred. The contact angle measured by water repellency evaluation was 135.9 ° and the water repellency was good. The obtained results are shown in Table 2.

[Comparative Example 5]
A sea-island composite fiber was produced in the same manner as in Example 1 except that a resin obtained by blending a polymethylpentene resin and polypropylene at a mass ratio of 20:80 was used as the sea component. The minimum thickness of the sea part in the obtained sea-island type composite fiber was 1.6 μm, and no peeling at the interface between the sea part and the island part was observed, and the yarn-making stability was good. The heat resistance was not good because fusing or fusing occurred during a dry heat treatment at 185 ° C. for 2 minutes. Moreover, it dye | stained dark blue without a color spot, and the dyeability was favorable. Due to the increase in surface tension, the contact angle was 133.9 ° and the water repellency was low. The obtained results are shown in Table 2.

[Comparative Example 6]
A polymethylpentene resin was used alone, spun from the die at 280 ° C., and the undrawn yarn was wound up at 800 m / min. Next, the obtained undrawn yarn was drawn at a drawing speed of 600 m / min and a draw ratio of 2.3 times to obtain a sea-island type composite fiber of 36 dtex / 24f. Even after 2 minutes of dry heat treatment at 185 ° C., it was excellent in heat resistance without fusing or fusing, but the polymethylpentene resin was white because it could not be dyed with disperse dye. The contact angle measured by water repellency evaluation was as good as 137.1 °. The obtained results are shown in Table 2.

  The sea-island type composite fibers obtained in Examples 1 to 4 had good peel resistance, dyeability, heat resistance, water repellency, and lightness, but the sea-island type composite fibers obtained from Comparative Examples were resistant to peeling. At least one of colorability, dyeability, and heat resistance was poor.

  The sea-island type composite fiber of the present invention can be made into various fiber structures and can be suitably used not only for clothing such as inner and sportswear, but also for industrial materials such as outdoor goods such as umbrellas and tents. it can.

a Sea part b Island part p Contact point on the outer periphery of the fiber q Intersection of the normal line on the outer periphery of the fiber and the outer periphery of the island part X Minimum thickness of the sea part

Claims (4)

It consists of a sea part and 3 or more and 20 or less island parts, and has a sea-island structure in which the joint surface between the sea part and the island part is continuous in the fiber length direction, and the following requirements (a) to ( e ) are satisfied. The sea-island type composite fiber to be filled.
(A) A polymethylpentene-based resin whose main component is polymethylpentene (b) An island component is polyethylene terephthalate (c) An area ratio of the sea part in the fiber cross section is greater than 50% and 75% or less (d) Fiber Minimum thickness of sea part in cross section is 1μm or more
(E) No fusing or fusing after dry heat treatment in a dry heat atmosphere at 185 ° C. The contact angle of water droplet, sea-island type composite fiber of claim 1, wherein at 135 ° or more. The sea-island composite fiber according to claim 1 or 2 , wherein the density is 1.10 g / cm ³ or less. The sea-island type composite fiber according to any one of claims 1 to 3 , wherein the single yarn fineness is 1 dtex or more.

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