Dyeable polypropylene fiber

Abstract

To provide a dyeable polypropylene fiber that has both characteristics of polypropylene and polyester, has improved wear resistance, has an excellent texture, and can be suitably adopted as a fiber structure.SOLUTION: There is provided a dyeable polypropylene fiber that is a polymer alloy fiber having a sea-island structure in which a polypropylene (A) is a sea component and a copolymerized polyester (B) is an island component, in which a coefficient of dynamic friction between fibers is 0.15 to 0.20.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to dyeable polypropylene fibers. [Background technology]

[0002] Polypropylene fiber, a type of polyolefin fiber, is lightweight and has excellent chemical resistance, but has the disadvantage that it is difficult to dye because it does not have a polar functional group. Therefore, it is not suitable for clothing applications, and is currently used in limited applications such as interior applications such as tile carpets, home rugs, and car mats, and materials such as ropes, protective nets, filter cloths, narrow tapes, braided cords, and upholstery.

[0003] One simple method for coloring polyolefin fibers is the addition of pigments, but it is difficult to consistently produce vivid colors or pale shades like dyes, and the use of pigments tends to make the fibers hard, reducing their flexibility.

[0004] Surface modification of polyolefin fibers has been proposed as an alternative dyeing method to pigments.

[0005] For example, in Patent Document 1, an attempt is made to improve dyeability by modifying the surface of polyolefin fibers through ozone treatment or graft copolymerization of a vinyl compound by ultraviolet irradiation.

[0006] In addition, a technique for compounding dyeable polymers with polyolefins that have low dyeability has been proposed. For example, Patent Document 2 proposes dyeable polyolefin fibers in which polyester or polyamide is blended with polyolefin as a dyeable polymer.

[0007] Furthermore, Patent Documents 3, 4, and 5 attempt to improve color development by making the dyeable polymer blended with polyolefin amorphous. Specifically, Patent Document 3 proposes a copolymer polyester copolymerized with cyclohexanedimethanol, Patent Document 4 proposes a copolymer polyester copolymerized with isophthalic acid and cyclohexanedimethanol, and Patent Document 5 proposes a dyeable polyolefin fiber in which a copolymer polyester copolymerized with cyclohexanedicarboxylic acid is blended with polyolefin as a dyeable amorphous polymer. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 7-90783 [Patent Document 2] Japanese Patent Application Publication No. 4-209824 [Patent Document 3] Special Publication No. 2008-533315 [Patent Document 4] Special Publication No. 2001-522947 [Patent Document 5] International Publication No. 2017 / 154665 Summary of the Invention [Problem to be solved by the invention]

[0009] In the method described in Patent Document 1, the ozone treatment and ultraviolet irradiation require long periods of time, resulting in low productivity and a high barrier to industrialization.

[0010] In addition, in the method of Patent Document 2, although it is possible to impart color development to polyolefin fibers using a dyeable polymer, since the dyeable polymer is crystalline, the color development is insufficient and the color lacks vividness and depth.

[0011] In the methods of Patent Documents 3 and 4, the color development is improved by making a dyeable polymer amorphous, but the vividness and depth of the color are still insufficient.

[0012] Thereafter, a dyeable polyolefin fiber excellent in vividness and depth was created by the method of Patent Document 5. However, when considering deployment in outdoor applications where a relatively strong load is applied and rubbing is repeated, there are cases where restrictions are imposed on the product form, such as the need to devise a structure of the fiber product depending on the environment and atmosphere in which it is used in order to maintain abrasion resistance and fastness. Therefore, a dyeable polypropylene fiber with even better abrasion resistance and color development is desired, and the present invention aims to solve the problems of the above-mentioned conventional technology and provide a dyeable polypropylene fiber with even improved abrasion resistance that can be suitably adopted as a fiber structure. [Means for solving the problem]

[0013] The above-mentioned problems can be solved by a dyeable polypropylene fiber, which is a polymer alloy fiber having an island-sea structure in which polypropylene (A) is the sea component and copolymer polyester (B) is the island component, and which is characterized in that the dynamic friction coefficient between yarns is 0.15 to 0.20. Effect of the Invention

[0014] According to the present invention, it is possible to provide a dyeable polypropylene fiber that combines the characteristics of both polypropylene and polyester, has improved abrasion resistance, and is excellent in texture. The dyeable polypropylene fiber obtained by the present invention can be made into a fiber structure, and can be suitably used in applications where excellent abrasion resistance and color development are particularly required in applications where conventional polypropylene-based fibers and polyester-based fibers are used. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The dyeable polypropylene fiber of the present invention is a polymer alloy fiber having an islands-in-sea structure in which polypropylene (A) is the sea component and copolymer polyester (B) is the island component, and has a dynamic friction coefficient between yarns of 0.15 to 0.20.

[0016] The polymer alloy fiber in the present invention is a fiber in which island components are discontinuously dispersed. Here, the island components are discontinuous means that the island components are present with an appropriate length in the fiber longitudinal direction, the length being tens of nm to hundreds of thousands of nm, and the shape of the sea-island structure in two cross sections perpendicular to the fiber axis, i.e., fiber cross sections, observed at any interval within the same single fiber, is different. The discontinuity of the island components in the present invention can be confirmed by the method described in the Examples. When the island components are present in a discontinuously dispersed state, the specific interfacial area of ​​the sea-island interface can be sufficiently increased, so that interfacial peeling can be suppressed, and a polymer alloy fiber having excellent mechanical properties and abrasion resistance can be obtained. In addition, since interfacial peeling is suppressed, when dyed, the decrease in color development due to the increase in scattered light caused by interfacial peeling can be suppressed, and a vivid and deep color development can be obtained. As described above, the polymer alloy fiber in the present invention is essentially different from a core-sheath composite fiber in which one island is formed continuously and in the same shape in the fiber axis direction, and a sea-island composite fiber in which multiple islands are formed continuously and in the same shape in the fiber axis direction. Such a polymer alloy fiber can be obtained, for example, by molding a polymer alloy composition formed by kneading polypropylene (A) and copolymer polyester (B) at any stage before the completion of melt spinning.

[0017] The sea component constituting the sea-island structure of the dyeable polypropylene fiber of the present invention is polypropylene (A).

[0018] The polypropylene (A) of the present invention may be a propylene homopolymer or a copolymer with other α-olefins. One or more of the other α-olefins (hereinafter sometimes simply referred to as α-olefins) may be copolymerized.

[0019] The number of carbon atoms in the α-olefin is preferably 2 to 20, and the molecular chain of the α-olefin may be linear or branched. Specific examples of the α-olefin include, but are not limited to, ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, and 3-ethyl-1-hexene.

[0020] The copolymerization rate of the α-olefin is preferably 20 mol % or less. If the copolymerization rate of the α-olefin is 20 mol % or less, it is preferable because a dyeable polypropylene fiber having good mechanical properties and heat resistance can be obtained.

[0021] The island components constituting the sea-island structure of the dyeable polypropylene fiber of the present invention are copolymer polyesters (B).

[0022] Methods for improving the color development of the dyeable polypropylene fiber of the present invention include reducing the crystallinity of the copolymerized polyester (B) and reducing the refractive index of the copolymerized polyester (B), but reducing the refractive index of the copolymerized polyester (B) can provide a greater effect.

[0023] Since dyes are not easily absorbed by crystalline portions but are easily absorbed by amorphous portions, in order to improve color development, the lower the crystallinity of the copolymerized polyester (B) the more preferable, and it is more preferable that the copolymerized polyester (B) is amorphous.

[0024] Furthermore, when the refractive index of the copolymer polyester (B) is reduced, the reflected light on the surface of the copolymer polyester (B) is reduced, and the light penetrates sufficiently into the copolymer polyester (B), thereby imparting vivid and deep color development. In order to reduce the refractive index of the copolymer polyester (B), it is effective to reduce the aromatic ring concentration of the copolymer polyester (B).

[0025] The copolymer polyester (B) of the present invention has a copolymerization component consisting mainly of terephthalic acid and ethylene glycol. The copolymerization dicarboxylic acid component may be phthalic acid, isophthalic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 5-sodium sulfoisophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,2'-biphenyldicarboxylic acid, 3,3'-biphenyldicarboxylic acid, 4,4'-biphenyldicarboxylic acid, anthracenedicarboxylic acid, or other aromatic dicarboxylic acid; malonic acid, fumaric acid, maleic acid, succinic acid, itaconic acid, adipic acid, azelaic acid, sebacic acid, 1,11-undecanedicarboxylic acid, 1,12 Examples of the copolymerized diol component include aromatic diols such as catechol, naphthalene diol, and bisphenol, and aliphatic diols such as trimethylene glycol, tetramethylene glycol, hexamethylene glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, neopentyl glycol, and cyclohexanedimethanol. These copolymerized components may be used alone or in combination of two or more.

[0026] The dyeable polypropylene fiber of the present invention preferably contains 5.0 to 20.0 parts by weight of the copolymer polyester (B) relative to 100 parts by weight of the total fiber composition. If the content of the copolymer polyester (B) is 5.0 parts by weight or more, the island components present in large numbers in the sea component are dyed, and the coloring efficiency by the light transmitted to the island components is improved, and vivid and deep coloring can be obtained, which is preferable. On the other hand, if the content of the copolymer polyester (B) is 20.0 parts by weight or less, the copolymer polyester (B), which has a low refractive index and high coloring properties, is scattered in the polypropylene (A), which has a low refractive index, so that vivid and deep coloring can be realized. In addition, it is preferable because the light weight, uniform dyeability, and quality of the polypropylene (A) are not impaired.

[0027] The dyeable polypropylene fiber of the present invention has a kinetic friction coefficient between yarns of 0.15 to 0.20. If the kinetic friction coefficient between yarns is 0.15 or more, sufficient friction is generated, and the yarns do not come apart when winding the yarn or forming a fabric. On the other hand, if the kinetic friction coefficient between yarns is 0.20 or less, excessive friction is not generated, and excessive frictional force is not generated on the fiber surface, so that polymer peeling on the fiber surface can be suppressed, thereby further improving abrasion resistance, and the processability is good, and the product form is not restricted, making it possible to develop it into outdoor applications. The kinetic friction coefficient between yarns in the present invention refers to the kinetic friction coefficient between yarns measured by the method described in the Examples.

[0028] The dyeable polypropylene fiber of the present invention preferably contains silicone (C) for the main purpose of further improving abrasion resistance. As lubricants for improving abrasion resistance, silicone, N,N'-ethylenebisstearylamide, stearic acid compounds, etc. are known, and among these, the inclusion of silicone, which is a high molecular weight substance, is preferable because it can suppress the outflow of components due to washing with water, and also reduces the friction coefficient of the dyeable polypropylene fiber, thereby further improving the abrasion resistance.

[0029] The dyeable polypropylene fiber of the present invention preferably contains 0.5 to 10.0 parts by weight of silicone (C) relative to 100 parts by weight of the total fiber composition. If the content of silicone (C) is 0.5 parts by weight or more, the friction coefficient of the fiber decreases and the abrasion resistance is further improved, and the charge bias caused by friction between polypropylene (A) and copolymer polyester (B) during melt spinning and between the pipe can be kept between the resins, and there is no charge bias in the resin after discharge from the spinneret, which is preferable because it improves productivity. The content of silicone (C) is preferably 1.0 part by weight or more. On the other hand, if the content of silicone (C) is 10.0 parts by weight or less, it is preferable because it does not impair the lightness, uniform dyeability, quality, and strength of the dyeable polypropylene fiber. The content of silicone (C) is more preferably 5.0 parts by weight or less.

[0030] The silicone (C) of the present invention is a polysiloxane compound. Examples of the side chain of the polysiloxane compound include, but are not limited to, hydrocarbon groups such as methyl groups and ethyl groups, and hydrocarbon groups modified with amino groups and epoxy groups. The end groups of the polysiloxane compound may be unmodified or modified with amino groups, epoxy groups, carboxyl groups, phenol groups, and carbinol groups, but are not limited to these. When modifying the ends of the polysiloxane compound, modification of only one end or modification of both ends may be performed. Here, the dyeable polypropylene fiber of the present invention is a polymer alloy fiber made of polypropylene (A) and copolymerized polyester (B), and when it is assumed that the fiber is deployed in outdoor applications where a relatively strong load is applied and rubbing is repeated, it is polypropylene (A) that wears. Therefore, in order to further improve the wear resistance, it is required to efficiently localize the silicone (C) in the polypropylene (A). In order to localize the polypropylene (A) rather than the copolymer polyester (B), a polysiloxane compound having a side chain with a hydrocarbon group such as a methyl group or an ethyl group that is not modified with a functional group and an unmodified end group is preferred. Among these, polydimethylsiloxane is particularly preferred.

[0031] The silicone (C) may be added as a post-processing method after fabric formation, or as a method of adding the silicone (C) before spinning and kneading it into the raw polymer. Of these, kneading it into the polymer is preferred because it is durable against washing with water. In addition, since the dyeable polypropylene fiber of the present invention is a polymer alloy fiber, the polypropylene (A) and the copolymer polyester (B) are finely dispersed during melt spinning, and friction occurs between the polypropylene (A) and the copolymer polyester (B), causing charge bias, and further causing charge bias between the polypropylene (A) and the copolymer polyester (B), so that the charge on the metal pipe side becomes positive and the charge of the fiber discharged from the spinneret becomes negative. During this melt spinning, if the molten resin contains silicone (C), the silicone (C) is more likely to become positively charged than metal piping, and therefore the charge bias occurs only in the molten resin and only in the fibers discharged from the spinneret. Therefore, when each single fiber is captured, there is no charge bias and there is no repulsion between the single fibers. From the viewpoint of improving productivity due to the deterioration of convergence, it is preferable to knead the silicone (C) into the yarn in advance.

[0032] In the present invention, a compatibilizer (D) may be added as necessary for the purpose of improving the dispersibility of the copolymerized polyester (B) of the island components in the polypropylene (A) of the sea component, controlling the dispersion state, and improving the interfacial adhesion between the sea component and the island components. When forming an island-sea structure by melt spinning, a bulge called ballas occurs just below the spinneret, and the thinning deformation of the fiber tends to become unstable. Therefore, a compatibilizer (D) may be used for the purpose of improving the spinning operability, such as suppressing yarn breakage associated with this ballas, and obtaining high-quality fibers with small unevenness in fineness and excellent uniformity in the fiber longitudinal direction.

[0033] The compatibilizer (D) in the present invention can be appropriately selected depending on the copolymerization rate of the copolymerization components of the copolymerized polyester (B), the composite ratio of the polypropylene (A) of the sea component and the copolymerized polyester (B) of the island component, etc. The compatibilizer (D) may be used alone or in combination of two or more kinds.

[0034] In the case where the compatibilizer (D) is added, the dyeable polypropylene fiber of the present invention preferably contains 0.1 to 10.0 parts by weight of the compatibilizer (D) relative to 100 parts by weight of the total yarn composition. If the content of the compatibilizer (D) is 0.1 parts by weight or more, the effect of compatibilizing the polypropylene (A) and the copolymer polyester (B) is obtained, the dispersion diameter of the island component is reduced, and the aggregation of the dye compound can be suppressed to approach monodispersion, so that the coloring efficiency is improved and a vivid and deep coloring can be obtained, which is preferable. In addition, it is preferable that the spinning operability, such as suppression of yarn breakage, is improved, and high-quality fibers with small fineness unevenness and excellent uniformity in the fiber longitudinal direction can be obtained. On the other hand, if the content of the compatibilizer (D) is 10.0 parts by weight or less, it is preferable that the fiber characteristics, appearance, and texture derived from the polypropylene (A) and the copolymer polyester (B) constituting the dyeable polypropylene fiber can be maintained. In addition, it is preferable that the instability of the spinning operability caused by an excessive amount of the compatibilizer can be suppressed.

[0035] The dyeable polypropylene fiber of the present invention preferably contains an antioxidant. By containing an antioxidant, not only is oxidative decomposition of polypropylene suppressed due to long-term storage or tumble drying, but the durability of fiber properties such as mechanical properties is improved, which is preferable.

[0036] The antioxidant in the present invention is preferably any one of a phenol-based compound, a phosphorus-based compound, a sulfur-based compound, and a hindered amine-based compound. These antioxidants may be used alone or in combination of two or more.

[0037] Next, the dyeable polypropylene fiber of the present invention will be described. The dyeable polypropylene fiber of the present invention is not particularly limited with respect to the form of the fiber, and may be in any form such as monofilament, multifilament, staple, or the like. The fineness of the dyeable polypropylene fiber of the present invention as a multifilament is not particularly limited and can be appropriately selected depending on the application and required properties, but is preferably 10 to 3000 dtex. The fineness in the present invention refers to a value measured by the method described in the Examples. If the fineness of the dyeable polyolefin fiber is 10 dtex or more, it is preferable because there is little yarn breakage, the processability is good, and the generation of fluff during use is small, resulting in excellent durability. On the other hand, if the fineness of the dyeable polyolefin fiber is 3000 dtex or less, it is preferable because the flexibility of the fiber and fiber structure is not impaired.

[0038] The elongation of the dyeable polypropylene fiber of the present invention is preferably adjusted by the manufacturing method described later depending on the application and required properties. Here, the elongation of the present invention refers to a value measured by the method described in the Examples, and the higher the elongation, the less likely the fiber will elongate and break even if it is subjected to sudden deformation, but since elongation and deformation during molding processing may cause the properties of the fiber product to become unstable, in consideration of the handleability of the fiber, the elongation of the fiber of the present invention is more preferably 30 to 60%. In particular, an elongation of 60% or less is preferable because the dimensional stability of the fiber and fiber structure is good.

[0039] The elongation of the fiber of the present invention may be adjusted according to the required elongation for its use, and it is particularly preferable to adjust it to 30 to 50% when used for clothing purposes, and 20 to 40% when used for non-clothing purposes.

[0040] The dyeable polypropylene fiber of the present invention is not particularly limited with respect to the cross-sectional shape of the fiber, and can be appropriately selected according to the application and required characteristics, and may have a perfectly circular cross section or a noncircular cross section. Specific examples of noncircular cross sections include, but are not limited to, multi-lobed, polygonal, flat, elliptical, C-shaped, H-shaped, S-shaped, T-shaped, W-shaped, X-shaped, Y-shaped, square, hollow, etc.

[0041] Next, a method for producing the dyeable polypropylene fiber of the present invention will be described below.

[0042] The single fiber fineness of the dyeable polypropylene fiber of the present invention is not particularly limited and can be appropriately selected depending on the application and required properties, but is preferably 0.5 to 20 dtex. The single fiber fineness in the present invention refers to the value obtained by dividing the fineness measured by the method described in the Examples by the number of single fibers. If the single fiber fineness of the dyeable polypropylene fiber is 0.5 dtex or more, it is preferable because there is little yarn breakage, the processability is good, and the generation of fluff during use is small, resulting in excellent durability. On the other hand, if the single fiber fineness of the dyeable polypropylene fiber is 20 dtex or less, it is preferable because the flexibility of the fiber and fiber structure is not impaired.

[0043] As a method for producing the dyeable polypropylene fiber of the present invention, a known melt spinning method or drawing method can be used.

[0044] In the present invention, it is preferable to dry the polypropylene (A), the copolymer polyester (B), the silicone (C) and the compatibilizer (D) before melt spinning to make the water content 0.3% by weight or less. If the water content is 0.3% by weight or less, foaming due to moisture does not occur during melt spinning, and stable spinning can be performed, which is preferable. In addition, it is preferable because the deterioration of mechanical properties and color tone due to hydrolysis is suppressed. The water content is more preferably 0.2% by weight or less, and even more preferably 0.1% by weight or less.

[0045] In the case of polymer alloy spinning, examples of the method of discharging from a spinneret to form a fiber thread include, but are not limited to, the following examples. As a first example, composite chips in which the sea component and island component are melt-kneaded in advance using an extruder or the like to homogenize the sea-island structure are dried as necessary, and then the chips are supplied to a melt spinning machine to be melted and metered with a metering pump. Thereafter, the chips are introduced into a heated spinning pack in a spinning block, and the molten polymer is filtered in the spinning pack, and then the chips are discharged from a spinneret to form a fiber thread. As a second example, the chips are dried as necessary, and the sea component and island component are mixed in the chip state, and then the mixed chips are supplied to a melt spinning machine to be melted and metered with a metering pump. Thereafter, the chips are introduced into a heated spinning pack in a spinning block, and the sea-island component of the molten polymer is kneaded and filtered in the spinning pack, and then the chips are discharged from a spinneret to form a fiber thread. As a third example, composite chips having a higher weight % of island components than the final fiber composition are dried as required, and then the composite chips and the sea component chips are separately fed and melted, and metered by a metering pump. Thereafter, the composite chips are introduced into a heated spinning pack in a spinning block, and the sea component chips of the molten polymer are kneaded and filtered in the spinning pack, and then discharged from a spinneret to form a fiber thread. As a fourth example, composite chips having a higher weight % of island components than the final fiber composition are dried as required, and then the composite chips and the sea component chips are mixed in the chip state, and then the mixed chips are fed into a melt spinning machine, where they are melted, and then measured by a metering pump. Thereafter, the composite chips are introduced into a heated spinning pack in a spinning block, and the sea component chips of the molten polymer are kneaded and filtered in the spinning pack, and then discharged from a spinneret to form a fiber thread.

[0046] The fiber yarn discharged from the spinneret is cooled and solidified by a cooling device, taken up by a first godet roller, and wound by a winder via a second godet roller to form a wound yarn. The tension during winding is preferably 0.05 to 0.10 cN / dtex. If the tension during winding is 0.05 cN / dtex or more, the tension between the second godet roller and the winder is sufficient, and stable winding can be performed, which is preferable. On the other hand, if the tension during winding is 0.10 cN / dtex or less, it is preferable because it can suppress deterioration of operability due to excessive rubbing of the yarn caused by high tension between the second godet roller and the winder, and changes in the physical properties of the inner layer and outer layer of the wound yarn due to shrinkage of the wound yarn over time. In addition, oil may be supplied to the fiber yarn using an oil supplying device, and entanglement may be imparted to the fiber yarn using an entanglement device.

[0047] The spinning temperature in melt spinning can be appropriately selected depending on the melting points and heat resistance of the polypropylene (A), the copolymer polyester (B), the silicone (C), and the compatibilizer (D), but is preferably 220 to 300°C. If the spinning temperature is 220°C or higher, the extensional viscosity of the fiber yarn discharged from the spinneret is sufficiently reduced, so that the discharge is stable, and further, the spinning tension does not become excessively high, so that yarn breakage can be suppressed, which is preferable. The spinning temperature is more preferably 240°C or higher. On the other hand, if the spinning temperature is 300°C or lower, it is preferable because the thermal decomposition during spinning can be suppressed, and the deterioration of the mechanical properties and coloring of the obtained dyeable polyolefin fiber can be suppressed. The spinning temperature is more preferably 260°C or lower.

[0048] The spinning speed in melt spinning can be appropriately selected depending on the composite ratio of polypropylene (A), copolymer polyester (B), silicone (C), and compatibilizer (D), spinning temperature, etc., but in the case of the two-step method, it is preferably 1000 to 3000 m / min. In the case of the two-step method, the spinning speed is preferably 1000 m / min or more, because the running yarn is stable and yarn breakage can be suppressed. In the case of the two-step method, the spinning speed is more preferably 1500 m / min or more. On the other hand, in the case of the two-step method, the spinning speed is preferably 3000 m / min or less, because the spinning tension can be suppressed to perform stable spinning without yarn breakage, and the change in the physical properties of the inner layer and outer layer of the wound yarn due to the shrinkage of the wound yarn after spinning can be suppressed. In the case of the two-step method, the spinning speed is more preferably 2500 m / min or less. In the case of a one-step method in which spinning and drawing are performed simultaneously without winding, the spinning speed is preferably 1000 to 3000 m / min for the low-speed roller and 2500 to 6000 m / min for the high-speed roller. If the low-speed roller and the high-speed roller are within the above ranges, the running yarn is stabilized, yarn breakage can be suppressed, and stable spinning can be performed, which is preferable.

[0049] When drawing is performed by a one-step method or a two-step method, either a one-stage drawing method or a multi-stage drawing method having two or more stages may be used. The heating method in drawing is not particularly limited as long as it is an apparatus capable of directly or indirectly heating the running yarn.

[0050] The drawing temperature when drawing can be appropriately selected depending on the glass transition temperature and melting point of the polypropylene (A), the copolymer polyester (B), the silicone (C), and the compatibilizer (D), the strength and elongation of the fiber after drawing, etc., but is preferably 30 to 120 ° C. If the drawing temperature is 30 ° C or higher, the yarn to be supplied for drawing is sufficiently preheated, the thermal deformation during drawing is uniform, the occurrence of fineness unevenness can be suppressed, and a high-quality fiber with excellent uniformity in the fiber longitudinal direction can be obtained, which is preferable. The drawing temperature is more preferably 50 ° C or higher. On the other hand, if the drawing temperature is 120 ° C or lower, it is preferable because it is possible to suppress fusion and thermal decomposition of the fibers caused by contact with the heating roller, and the process passability and quality are good. In addition, it is preferable because the slippage of the fiber against the drawing roller is good, yarn breakage is suppressed, and stable drawing can be performed. The drawing temperature is more preferably 90 ° C or lower. In addition, it is preferable to perform heat setting at 120 to 150 ° C. Heat setting at 120°C or higher is preferable because the heat-set fiber is sufficiently crystallized, and changes in the physical properties of the inner and outer layers of the fiber after drawing due to shrinkage over time can be suppressed. On the other hand, a heat setting temperature of 150°C or lower is preferable because fusion between the fibers and thermal decomposition can be suppressed, and the processability and quality are good.

[0051] The draw ratio when drawing can be appropriately selected depending on the elongation of the fiber before drawing and the strength and elongation of the fiber after drawing, but is preferably 1.02 to 5.0 times. A draw ratio of 1.02 times or more is preferable because mechanical properties such as the strength and elongation of the fiber can be improved by drawing. A draw ratio of 1.2 times or more is more preferable. On the other hand, a draw ratio of 5.0 times or less is preferable because thread breakage during drawing is suppressed and stable drawing can be performed. A draw ratio of 3.5 times or less is more preferable.

[0052] The stretching speed when stretching can be appropriately selected depending on whether the stretching method is a one-step method or a two-step method. In the case of a one-step method, the speed of the high-speed roller at the above spinning speed corresponds to the stretching speed. In the case of a two-step method, the stretching speed is preferably 100 to 1000 m / min. If the stretching speed is 100 m / min or more, the running yarn is stabilized and thread breakage is suppressed, which is preferable. On the other hand, if the stretching speed is 1000 m / min or less, thread breakage during stretching is suppressed and stable stretching can be performed, which is preferable. EXAMPLES

[0053] The present invention will be described in more detail below with reference to examples. The property values ​​in the examples were determined by the following methods.

[0054] A. Composite ratio The total amount of the sea component (A), island component (B), silicone (C) and compatibilizer (D) used as the raw materials for the dyeable polypropylene fiber was set to 100 parts by weight, and the composite ratio was calculated as sea component (A) / island component (B) / silicone (C) / compatibilizer (D) [parts by weight].

[0055] B. Fineness 100 m of the fiber obtained in the examples was spooled using an INTEC electric measuring machine under an environment of 20° C. temperature and 65% RH. The weight of the spool obtained was measured, and the fineness (dtex) was calculated using the following formula. Fineness (dtex) = weight of 100m of fiber (g) x 100 The measurement was carried out five times for each sample, and the average value was regarded as the fineness.

[0056] C. Strength, elongation The strength and elongation were calculated according to JIS L1013:2010 (chemical fiber filament yarn test method) 8.5.1 using the fibers obtained in the examples as samples. A tensile test was performed using an Orientec Tensilon UTM-III-100 model under conditions of a temperature of 20°C and a humidity of 65% RH, with an initial sample length of 20 cm and a tensile speed of 20 cm / min. The strength (cN / dtex) was calculated by dividing the stress (cN) at the point showing the maximum load by the fineness (dtex), and the elongation (%) was calculated according to the following formula using the elongation (L1) at the point showing the maximum load and the initial sample length (L0). Elongation (%)={(L1-L0) / L0}×100 The measurement was carried out 10 times for each sample, and the average values ​​were used as the strength and elongation.

[0057] D. Toughness The toughness was calculated by the following formula using the strength (cN / dtex) and elongation (%) calculated in C above. Toughness = Strength x Elongation 0.5} .

[0058] E. Coefficient of kinetic friction between yarns The coefficient of friction was calculated using an Eiko Industrial silk-reeling running friction coefficient measuring device ME-TM1, with the number of yarn-yarn crossings counted as one, at a yarn speed of 55 m / min for 30 seconds.

[0059] F. Island discontinuity The fibers obtained in the examples were embedded in epoxy resin, and then cut in a direction perpendicular to the fiber axis together with the epoxy resin using an LKB ultramicrotome LKB-2088 to obtain ultrathin sections with a thickness of about 100 nm. The obtained ultrathin sections were stained by holding them in a gas phase of ruthenium tetroxide at room temperature for about 4 hours, and then the stained surface was cut with an ultramicrotome to prepare ultrathin sections stained with ruthenium tetroxide. The stained ultrathin sections were observed at arbitrary intervals of at least 10,000 times the diameter of the single fiber at an acceleration voltage of 100 kV using a Hitachi transmission electron microscope (TEM) H-7100FA model, and five micrographs of the fiber cross sections were taken. When the number of island components and the shape of the sea-island structure in each fiber cross section were different in the photographs, the island components were determined to be discontinuous. When the island components were discontinuous, they were rated as "Y," and when they were not discontinuous, they were rated as "N."

[0060] GL * value The fibers obtained in the examples were used as samples, and about 2 g of tubular knitting was produced using an Eiko Sangyo circular knitting machine NCR-BL (3.5 inch (8.9 cm) diameter, 27 gauge). The tubular knitting was then scoured for 20 minutes at 80°C in an aqueous solution containing 1.5 g / L sodium carbonate and 0.5 g / L Meisei Chemical Co., Ltd. surfactant Grand Up US-20, washed with running water for 30 minutes, and dried for 60 minutes in a hot air dryer at 60°C. The tubular knitting after scouring was dry-heat set for 1 minute at 135°C, and the dry-heat set tubular knitting was dyed for 45 minutes at 130°C in a dyeing solution containing 8% by weight of Huntsman's TERASIL BLACK WW-KSN as a black disperse dye and 1 g / L of Sanyo Chemical Industries' IONET RAP-250 as a leveling dyeing agent, with the pH adjusted to 5.0, at a bath ratio of 1:40, and then washed with running water for 30 minutes and dried for 60 minutes in a hot air dryer at 60°C. After dyeing, the tubular knit was washed with an alkaline solution containing 0.6 g / L sodium hydroxide at a bath ratio of 1:40 for 20 minutes at 80°C, then rinsed with running water for 30 minutes and dried in a hot air dryer at 60°C for 60 minutes. After the alkaline washing, the tubular knit was dry-heat set at 135°C for 1 minute and finished. The tubular knit after the finish setting was used as a sample and measured using a Minolta CM-3700d spectrophotometer with a D65 light source, a viewing angle of 10°, and optical conditions of SCE (specular reflection excluded method) for L. * The measurement was performed three times for each sample, and the average value was calculated as L * The value was set as

[0061] H. Color development The cylindrical knitted fabrics produced in G above after finishing and setting were evaluated on a four-level scale of S, A, B, and C by a consensus of five inspectors with over five years of experience in judging quality. S indicates the best, followed by A, B, and C, with C being the worst. S indicates "sufficient vivid and deep coloring," A indicates "generally sufficient vivid and deep coloring," B indicates "almost no vivid and deep coloring," and C indicates "dyed unevenly with clear dye spots." A or above for "generally sufficient vivid and deep coloring" was considered a pass.

[0062] I. Level staining The cylindrical knitted fabrics produced in G above after finishing and setting were evaluated on a four-level scale of S, A, B, and C by a consensus of five inspectors with over five years of experience in judging quality. S indicates the best, followed by A, B, and C, in order of worsening, with C being the worst. S indicates "very evenly dyed with no visible dye spots," A indicates "almost evenly dyed with almost no visible dye spots," B indicates "almost evenly dyed with faint dye spots," and C indicates "almost evenly dyed with obvious dye spots." A and above "almost evenly dyed with almost no visible dye spots" were considered to pass.

[0063] J. Dignity The cylindrical knitted fabrics produced in G above after finishing and setting were evaluated on a four-level scale of S, A, B, and C by a consensus of five inspectors with over five years of experience in judging quality. S indicates the best, followed by A, B, and C, in order of deterioration, with C being the worst. S indicates "sufficient vivid and deep coloring and extremely excellent quality," A indicates "generally sufficient vivid and deep coloring and excellent quality," B indicates "almost no vivid and deep coloring and poor quality," and C indicates "very little vivid and deep coloring and extremely poor quality." A or above for "generally sufficient vivid and deep coloring and excellent quality" was considered a pass.

[0064] K. Abrasion resistance (frosting evaluation, presence or absence of fibrillation) The tubular knitted fabrics after finishing set produced in G above were set on the top and bottom of an appearance retention type testing machine described in JIS1076 (2012) and abraded for 10 minutes with a pressing force of 7.4N. The degree of discoloration was then evaluated on a scale of 1 to 5 (9 stages). The yarns were also observed at 50x magnification with a Keyence Corporation VHX-2000 microscope for the presence or absence of fuzzing (fibrillation) and rated on a 3-stage scale of S, A, and B. S indicates the best grade, followed by A, and B indicates the worst grade. "No change (no fibrillation)" was rated as S, "some fibrillation" as A, and "clear fibrillation" as B.

[0065] Example 1 The mixture was mixed with 87.0% by weight of polypropylene (PP) (PP3155E5 manufactured by ExxonMobil, melting peak temperature 163°C, MFR 36g / 10min) as the sea component (A), 10.0% by weight of polyethylene terephthalate copolymerized with 35 mol% of 1,4-cyclohexanedicarboxylic acid as the island component (B), 1.0% by weight of polydimethylsiloxane (X-22-2101 manufactured by Shin-Etsu Chemical Co., Ltd., silicone master pellets with a PP matrix, 50 parts by weight of polydimethylsiloxane, and the remaining 50 parts by weight of PP are included in the composite ratio of polypropylene (A) in the table) as the silicone (C), and 1.0% by weight of styrene-butadiene-butylene-styrene copolymer having an amino group as a functional group (Tuftec (registered trademark) MP10 manufactured by Asahi Kasei Co., Ltd.) as the compatibilizer (D). The mixture was mixed at a mixing temperature of 230°C using a twin-screw extruder. The strand discharged from the twin-screw extruder was water-cooled, then cut to about 5 mm length with a pelletizer to obtain composite chips. The obtained composite chips were vacuum-dried at 90 ° C for 12 hours, then fed to an extruder-type melt spinning machine to melt, and discharged from a spinneret (discharge hole diameter 0.20 mm, discharge hole length 0.50 mm, number of holes 48, round hole) at a spinning temperature of 240 ° C and a discharge rate of 28.0 g / min to obtain a spun yarn. This spun yarn was cooled with cooling air at an air temperature of 20 ° C and an air speed of 25 m / min, and oil was applied with an oiling device to converge, taken up by a first godet roller rotating at 2000 m / min, passed through a second godet roller rotating at the same speed as the first godet roller, and wound by a winder to obtain an undrawn yarn of 140 dtex-48f. The obtained undrawn yarn was drawn under the conditions of a first hot roller temperature of 60° C., a second hot roller temperature of 140° C., and a draw ratio of 2.5 times to obtain a drawn yarn of 56 dtex-48f.

[0066] The evaluation results of the fiber properties and fabric properties of the obtained fiber are shown in Table 1. The obtained polypropylene fiber was at an acceptable level in terms of color development, dye levelness, grade, and abrasion resistance.

[0067] (Examples 2 to 6, Comparative Examples 1 and 2) A drawn yarn was produced in the same manner as in Example 1, except that the compounding ratio of polypropylene (A), copolymer polyester (B), silicone (C) and compatibilizer (D) was changed as shown in Table 1.

[0068] The evaluation results of the fiber properties and fabric properties of the obtained fibers are shown in Table 1. In Comparative Examples 1 and 2, the yarn-yarn dynamic friction coefficient was high, and the abrasion resistance against strong friction was poor.

[0069] (Examples 7 to 10) The drawn yarn was prepared in the same manner as in Example 1, except that the type of silicone (C) was changed to polydimethylsiloxane modified at both ends with amines in Example 7, to polydimethylsiloxane modified at both ends with carboxylic acids in Example 8, to polydimethylsiloxane modified at both ends with phenols in Example 9, and to polydimethylsiloxane modified at both ends with carboxylic anhydrides in Example 10.

[0070] The evaluation results of the fiber properties and fabric properties of the obtained fibers are shown in Table 2. In all cases where any silicone was used, the abrasion resistance was lower than in Example 1, where unmodified polydimethylsiloxane was used, but all were at an acceptable level.

[0071] (Examples 11 to 15) Except for changing the copolymer polyester (B) to polyethylene terephthalate copolymerized with 25 mol% isophthalic acid and 10 mol% adipic acid, drawn yarns were prepared in the same manner as in Example 1 for Example 11, Example 12 for Example 2, Example 13 for Example 3, Example 14 for Example 4, and Example 15 for Example 5.

[0072] The evaluation results of the fiber properties and fabric properties of the obtained fiber are shown in Table 3. Even when the copolymerized polyester (B) was changed to polyethylene terephthalate copolymerized with 25 mol% isophthalic acid and 10 mol% adipic acid, the obtained polypropylene fiber had excellent abrasion resistance, and was at an acceptable level for color development, dye levelness, and quality, just as in the case when the copolymerized polyester (B) was polyethylene terephthalate copolymerized with 35 mol% 1,4-cyclohexanedicarboxylic acid.

[0073] [Table 1]

[0074] [Table 2]

[0075] [Table 3] [Industrial Applicability]

[0076] The dyeable polypropylene fiber of the present invention combines the properties of both polypropylene and polyester, has improved abrasion resistance, and is excellent in texture, and thus provides a dyeable polypropylene fiber that can be suitably used as a fiber structure.

Claims

1. A dyeable polypropylene fiber, which is a polymer alloy fiber having an island-sea structure in which polypropylene (A) is a sea component and copolymer polyester (B) is an island component, contains 0.5 to 10.0 parts by weight of silicone (C) per 100 parts by weight of the total fiber composition, and has a dynamic friction coefficient between yarns of 0.15 to 0.

20.

2. 2. Dyeable polypropylene fiber according to claim 1, characterized in that the silicone (C) is polydimethylsiloxane.

3. A fiber structure characterized in that at least a portion of the fiber structure is made of the dyeable polypropylene fiber described in claim 1 or 2.

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