JP2015175066A - Core sheath conjugate fiber having friction melt resistance, and woven or knitted fabric using the fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a core sheath conjugate fiber and a woven or knitted fabric which suppress generation of melt holes caused by friction heat due to friction with a floor face in exercise in a gymnasium, a ball game field equipped with artificial lawn, and the like, and prevent a wearer from suffering from a skin laceration.SOLUTION: The core sheath conjugate fiber is composed of a polymer of a core part having a melting point lower than that of a polymer of a sheath part. The polymer of the core part is an olefinic polymer containing 1.0-30.0 wt% of a crystalline α-olefin having a melting point of 20-50°C, and the sheath part is composed of a thermoplastic polymer having a melting point of not lower than 200°C, so that the crystalline α-olefin dispersed in the core part receives the heat energy given by friction and melts endothermically, and further the olefinic polymer composing the core part repeats endothermic melting to suppress rise in temperature so that the sheath part is prevented from generating holes by melting.

Description

  In the present invention, the amount of heat generated when rubbing vigorously with a floor surface of a gymnasium or the like is quickly absorbed by the crystalline α-olefin and copolymer polyolefin of the core portion to suppress perforation due to melting of the sheath portion. It is related with the core-sheath composite fiber which has property.

  When woven or knitted fabrics composed only of synthetic fibers such as polyester fibers and nylon fibers are used as clothing for sports clothing, etc., synthetic fibers are generated by frictional heat generated when they are violently rubbed against the floor surface of gymnasiums, etc. There are problems such as melting holes on the surface and tearing of the wearer's skin. Such problems are particularly increasing due to the recent increase in indoor playgrounds with wooden floors and ballparks with artificial turf.

  Therefore, in order to improve the problems of the synthetic fibers as described above, there is a method of mixing the synthetic fibers with cotton by knitting, knitting, knitting or the like to prevent melting holes in the woven or knitted fabric. In this method, even if frictional heat is generated on the fiber surface, the cotton remains without melting, so that it is possible to prevent the formation of melting holes, but the synthetic fiber side melting cannot be suppressed, and the synthetic fiber melts on the surface of the woven or knitted fabric. Traces are produced. Also, during intense exercise in an indoor playground such as a gymnasium or during high temperatures and high humidity in summer, a lot of sweat is generated, the skin side gets wet and sticky, and the fabric clings to the body, which tends to cause discomfort. Furthermore, since the dyeability of synthetic fibers and cotton are greatly different, there is a problem that it is difficult to uniformly dye the fabric and the processing cost is increased.

  Patent Document 1 describes a technique for performing various types of friction-resistant melt processing on a woven or knitted fabric made of synthetic fibers. As a general example, a surface treatment that improves the smoothness of the surface of the knitted fabric by applying a finishing agent mainly composed of silicon to the woven or knitted fabric made of synthetic fibers, and reduces the frictional resistance with the floor surface, etc. Has been given. However, there is a problem that the surface treatment processing is lowered by repeated washing, and the smoothness is lowered.

  Patent Document 2 describes a woven or knitted fabric using a core-sheath type composite fiber using a polymer having a temperature of 200 ° C. or more in the sheath and a copolymer polyethylene polymerized using a metallocene catalyst in the core. Since the core polyethylene melts and absorbs heat generated by friction with the floor surface and the like, the temperature rise of the sheath portion is prevented and the occurrence of melting holes is prevented. However, there is a lack of frictional fusion resistance, and further, crimpability at the time of false twisting is a problem.

JP-A-8-284073 JP 2000-096350 A

  The object of the present invention is to solve such problems in the prior art. Specifically, a core-sheath composite that prevents the formation of melting holes due to frictional heat generated when rubbing against the floor surface during exercise in gymnasiums or artificial turf ball fields, and prevents wearer's skin tears, etc. Fibers and knitted fabrics are provided.

  As a result of intensive studies to solve the above problems, the present inventors have found that the core polymer is a core-sheath composite fiber having a melting point lower than that of the sheath polymer, and the core polymer has a melting point. It is an olefin polymer containing 1.0 to 30.0 wt% of crystalline α-olefin at 20 to 50 ° C., and by making the sheath part a thermoplastic polymer having a melting point of 200 ° C. or more, by friction The crystalline α-olefin dispersed in the core receives the applied thermal energy and absorbs and melts it, and the olefin polymer that forms the core repeats endothermic melting to prevent temperature rise on the fiber surface. The present invention has been completed by finding out that perforation due to melting of the sheath portion is prevented.

  In the present invention, the olefin polymer used for the core portion is preferably a copolymer polyethylene or copolymer propylene having a melting point of 30 ° C. or more lower than that of the sheath polymer, more preferably 170 ° C. or less. It is said core-sheath composite fiber characterized by being.

  In the present invention, the thermoplastic polymer used for the sheath is preferably a polyester polymer having a melting point of 240 ° C. or higher, more preferably a main repeating unit composed of a repeating unit of polyethylene terephthalate. The core-sheath composite fiber described above.

  Furthermore, the present invention is preferably the above-described core-sheath composite fiber, wherein the mass composite ratio of the core part to the sheath part is 5:95 to 40:60, more preferably the cross-sectional shape is a concentric circle shape. .

  And this invention includes the fiber structure characterized by containing 10 wt% or more of said core-sheath composite fibers.

  In the conjugate fiber obtained by the present invention, the crystalline α-olefin in which the core is dispersed undergoes an endothermic reaction due to melting, and further, the olefin polymer forming the core repeats endothermic melting, so that In addition to preventing temperature rise and preventing the occurrence of perforation due to melting of the sheath part, compared to conventional products, the range of conditions for false twisting is widened, and fibers with high crimp elongation can be obtained. Suitable for all clothing.

  One of the important features of the core-sheath composite fiber of the present invention is that the core portion contains a crystalline α-olefin. The crystalline α-olefin is generally a thermoplastic polymer having a melting point in the range of 10 to 80 ° C., but when used for the core-sheath composite fiber of the present invention, if the melting point is less than 20 ° C., the olefin-based polymer that forms the core is used. Since melt kneading into the coalescence becomes difficult, it is necessary to select a crystalline α-olefin having a melting point of 20 ° C. or higher. In addition, with crystalline α-olefins exceeding 50 ° C., the difference between the melting point of the olefin polymer forming the core portion becomes small, making it difficult to endothermically melt at the core portion step by step, and the friction-proofing performance. Is insufficient and unsuitable. Therefore, it is important that the melting point of the crystalline α-olefin used in the present invention is 20 to 50 ° C., preferably 30 to 50 ° C. Examples of such a crystalline α-olefin include “ELCRYSTA C-4100” manufactured by Idemitsu Kosan Co., Ltd.

  For the polymer at the core of the core-sheath composite fiber of the present invention, it is necessary to use an olefin polymer from the viewpoint of compatibility with crystalline α-olefin and melt moldability. There is no problem as long as the olefin polymer is a polymer that can melt-knead the crystalline α-olefin, and copolymerized polyethylene or single polyethylene, copolymerized polypropylene, or single polypropylene can be used. Among these, copolymer polyethylene or copolymer polypropylene having a melting point of 170 ° C. or lower is preferable because it is highly compatible with the crystalline α-olefin, is inexpensive and has high versatility.

  In the olefin polymer of the core part, it is important that the crystalline α-olefin is contained in an amount of 1.0 to 30.0 wt%. If it is less than 1.0 wt%, the friction-fusibility decreases due to poor dispersibility in the olefin polymer, and if it exceeds 30 wt%, the high-speed spinnability is insufficient, which is not suitable. Preferably it is 5.0-15.0 wt%.

  On the other hand, the polymer used for the sheath in the present invention needs to be a thermoplastic polymer having a melting point of 200 ° C. or higher. When the melting point is less than 200 ° C., the heat resistance due to frictional heat is low, so it cannot be used. From the viewpoint of increasing the heat resistance, a thermoplastic polymer having a melting point of 240 ° C. or higher is preferred. Polyamide used for general apparel or polyester such as polyethylene terephthalate is preferable, and there is no problem even if the main repeating unit is a polyester polymer composed of repeating units of polyethylene terephthalate.

  Moreover, it is preferable that melting | fusing point of the olefin polymer of the said core part is 30 degreeC or more lower than the thermoplastic polymer of the said sheath part. When the difference between the melting points of the two types of polymers is less than 30 ° C., it is not preferable because the generated frictional heat is difficult to exchange. More preferably, the melting point of the core polymer is 50 ° C. or lower than that of the sheath polymer.

  In the core-sheath conjugate fiber of the present invention, the mass composite ratio of the core part to the sheath part is preferably 5:95 to 40:60, more preferably 7:93 to 20:80. When the ratio of the core polymer is less than 5 wt%, sufficient friction-proofing performance cannot be obtained, and when it exceeds 40%, the yarn-making processability may be deteriorated.

  In the core-sheath composite fiber of the present invention, the ratio of the fiber diameter D ′ to the core diameter D is preferably 1.4 ≦ D ′ / D. When D ′ / D is less than 1.4, the heat resistance due to frictional heat is insufficient, and the spinnability is deteriorated and the texture becomes insufficient due to false twisting.

  The cross-sectional shape of the core-sheath conjugate fiber of the present invention can be selected from arbitrary shapes such as a circular shape and an irregular shape, but is preferably a concentric shape from the viewpoint of ensuring the thickness of the sheath portion.

  In the above-described composite fiber, the thickness of the fiber is not particularly limited, and can be any thickness. Moreover, the effect of the invention is expected not only for long fibers but also for short fibers.

  The core-sheath conjugate fiber of the present invention is not limited to the effects of the present invention, and other thermoplastic resins, fluorescent whitening agents, stabilizers, antioxidants are included in the polymer forming the core and / or sheath. 1 type (s) or 2 or more types of an agent, a ultraviolet absorber, a hydrolysis inhibitor, an antistatic agent, a flame retardant, a coloring agent, and another additive may be contained.

Next, the manufacturing method of the composite fiber of this invention is demonstrated below.
First, the core polymer and the sheath polymer are melt-extruded by separate extruders, introduced into a spinning head, and melt-spun through a spinneret that forms each desired composite shape. be able to. Further, in order to ensure the quality required for the final product and good processability, an optimum spinning / drawing method can be selected. More specifically, a spin draw method, a 2-step method in which a spinning raw yarn is collected and then drawn in a separate process, or a drawing speed of 2000 m / min or more without drawing is used as a non-drawn yarn. Even in the taking method, the composite fiber product having a good heat-shielding effect and color developability can be obtained by making the product after passing through an arbitrary yarn processing step.

  In the spinning process of the production method of the present invention, spinning is performed from a die using a normal melt spinning apparatus. Moreover, it is possible to arbitrarily set the cross-sectional shape and diameter of the obtained fiber depending on the shape and size of the die.

  The composite fiber obtained in the present invention can be used as various fiber assemblies. Here, the fiber assembly means not only a woven or knitted fabric or nonwoven fabric made of the fiber of the present invention alone, but also a woven or knitted fabric or nonwoven fabric made of a part of the fiber of the present invention, such as natural fiber, chemical fiber, synthetic fiber, etc. It may be a knitted woven fabric with other fibers such as fibers, or a blended yarn, a woven or knitted fabric used as a blended yarn, a blended nonwoven fabric, etc., but the proportion of the present invention fiber in the woven or knitted fabric or nonwoven fabric is 10 wt% or more, Preferably it is 30 wt% or more.

  As the main use of the core-sheath composite fiber of the present invention, a long fiber can be used alone or in part to create a woven or knitted fabric or the like, which can be used as a clothing material with a good texture. When used as a material for clothing, it is preferable to perform false twisting. In this respect, the conjugate fiber of the present invention is excellent in crimpability. In the prior art as shown in Patent Document 2, puncture at the time of false twisting, that is, the sheath is cracked and the core is exposed to the fiber surface and the heat fixation becomes unstable. It was difficult to have. On the other hand, since the composite fiber of the present invention is less prone to puncture and processing conditions can be set more freely, the crimp elongation rate can be increased, and a fiber having sufficient swelling can be obtained.

  The composite fiber obtained in the present invention preferably has a fastness to washing of 4th grade or more due to discoloration, attached contamination, and liquid contamination. If any of them is grade 3 or lower, it is not preferable for general clothing use from the viewpoint of handleability.

  Moreover, it is preferable that the composite fiber obtained by this invention is light-fastness 4th grade or more. When the light fastness is 3rd grade or less, it is not preferable for general clothing use from the viewpoint of handleability.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited at all by these Examples. In addition, the measured value in an Example is measured with the following method.

<Friction-proof property>
Using a rotor-type frictional fusion tester, attach a test piece (3.5 cm x 8.5 cm) to the arm, and then rotate the Sakuragi roller at 1800 rpm to adhere the test piece to the roller with a 2.0 kg load. The time when the test piece was melted was measured.

<Spinnability>
Spinnability was evaluated according to the following criteria.
(Double-circle): Spinning is very good, such as continuous spinning for 24 hours, no yarn breakage during spinning, and no fluff or loops in the obtained polyester fiber.
○: After continuous spinning for 24 hours, yarn breakage during spinning occurred at a frequency of 1 or less, and the resulting polyester fiber had no fluff or loops at all, or a slight occurrence, but spinnability Is almost good.
(Triangle | delta): Continuous spinning of 24 hours is performed, and the yarn breakage at the time of spinning occurs from 2 to 3 times, and the spinnability is poor.
X: 24 hours of continuous spinning was performed, the yarn breakage during spinning occurred more than 3 times, and the spinnability was extremely poor.

<Crimp elongation>
(1) Sample sampling: A small casket of 11110 dtex (10000 d) was made with a manual measuring machine under a tension of 0.044 cN / dtex (0.05 g / d). In the above, dtex is decitex, d is denier, and the same applies to the following.
(2) After applying a small amount of water to a small casserole (with a load of 10 g) and uniforming the small casserole, place it in a 90 ° C constant temperature bath (90 ° C, 30 minutes) and remove the load after relaxing. And dried.
(3) A load of 10 g was applied to the dried small case, and the case length was measured with a measuring device with a scale after 5 minutes. This is L1.
(4) A load of 1000 g (0.0088 cN / dtex) (0.01 g / d) was applied to the small case, and the case length after 30 seconds was measured. This is L2.
(5) Calculation formula K1 (crimp expansion rate) = (L2−L1) / L2 × 100.

<Example 1>
Using a polyethylene (PE) containing 5.0 wt% crystalline α-olefin having a melting point of 42 ° C. in the core and polyethylene terephthalate (PET) in the sheath, the mass composite ratio of the core and the sheath is 10:90 Under the conditions, spinning was performed at a spinning temperature of 260 ° C. and a single-hole discharge rate of 1.23 g / min using a base having 24 holes (hole diameter of 0.25 mmφ), and cooling air at a temperature of 25 ° C. and a humidity of 60% was set to 0. After setting the sprayed yarn on the spun yarn at a speed of 4 m / sec to 60 ° C. or less, the length set at a position 1.2 m below the spinneret, the inlet guide system 8 mm, the outlet guide system 10 mm, After being introduced into a tube heater (inner temperature 185 ° C.) with an inner diameter of 30 mmφ and stretched in the tube heater, the yarn coming out from the tube heater was lubricated with an oiling nozzle and passed through two take-up rollers at a speed of 3500 m / min. Tapping After refining the tubular knitted fabric having a basis weight of 200 g / m ² using the composite fibers of the resulting concentric were conducted various measurements. Friction resistance, spinnability, and crimp elongation are shown in Table 1. The composite fiber was very excellent in the friction-proof property of 29 s, and the spinnability and crimpability were also excellent. Moreover, when dyed after false twisting, it showed the same color developability as conventional polyester fibers. Further, the fastness to washing and the fastness to light of the obtained composite fiber were 4th grade or higher, and there was no problem.

<Examples 2 to 6>
Next, the melting point and content of the core and sheath polymer and the crystalline α-olefin contained in the core were changed as shown in Table 1, and the composite of 84T / 24f was spun by the same method as in Example 1. A fiber filament was obtained. Table 1 shows the physical properties of the obtained fiber. In all cases, good anti-friction performance, spinnability and crimp elongation were obtained, and the quality was satisfactory. In Table 1, “PP” refers to polypropylene, “Ny6” refers to nylon 6, and “modified PET” used for the sheath portion of Example 4 has 88.3 mol% of terephthalic acid in the dicarboxylic acid component. A total carboxylic acid component containing 1.7 mol% of 5-sodium sulfoisophthalic acid, 5.0 mol% of 1,4-cyclohexanedicarboxylic acid and 5.0 mol% of adipic acid, and ethylene. It is a modified polyethylene terephthalate obtained by adding transesterification and polycondensation reaction by adding glycol and titanium oxide as a matting agent.

<Comparative Example 1>
A composite fiber filament was obtained in the same manner as in Example 1 except that an olefin polymer containing no crystalline α-olefin was used in the core. Since no crystalline α-olefin was contained in the core, sufficient friction-proofing performance could not be obtained. Furthermore, the false twisted yarn of the obtained composite fiber had a low crimp elongation rate.

<Comparative Example 2>
A composite fiber filament was obtained in the same manner as in Example 1 except that 10.0 wt% of a crystalline α-olefin having a melting point of 80 ° C. was used. The spinnability and crimp elongation rate were reasonable, but the melting point of the crystalline α-olefin was too high, so that sufficient friction-proofing performance could not be obtained.

<Comparative Example 3>
In order to use it as a core polymer, an attempt was made to melt-knead a crystalline α-olefin having a melting point of 10 ° C. with Ny6, but a polymer that could be subjected to a spinning test could not be obtained.

<Comparative Example 4>
A composite fiber filament was obtained in the same manner as in Example 1 except that a core olefin polymer containing 40.0 wt% of crystalline α-olefin was used in the core, but the spinnability was extremely deteriorated. However, the raw yarn could not be obtained.

<Comparative Example 5>
A composite fiber filament was obtained in the same manner as in Example 1 except that nylon 12 (Ny12) was used for the sheath. The polymer of the sheath portion is Ny12 having a melting point of less than 200 ° C., and the heat resistance of the sheath portion is low, so that sufficient friction-proofing performance was not obtained.

  The composite fiber of the present invention suppresses the generation of melting holes when the frictional heat is applied to the clothing surface due to sliding or falling in an indoor sports field with a wooden floor or an artificial turf ball field, etc. It is suitable for general clothing such as sportswear.

Claims (8)

  The core polymer is a core-sheath composite fiber having a melting point lower than that of the sheath polymer, and the core polymer contains crystalline α-olefin having a melting point of 20 to 50 ° C. in an amount of 1.0 to 30. A core-sheath conjugate fiber, which is an olefin polymer containing 0 wt%, and wherein the sheath is a thermoplastic polymer having a melting point of 200 ° C. or higher.   The core-sheath conjugate fiber according to claim 1, wherein the polymer of the core part has a melting point lower by 30 ° C or more than the polymer of the sheath part.   The core-sheath conjugate fiber according to claim 1 or 2, wherein the olefin polymer used in the core is a copolymer polyethylene or a copolymer polypropylene having a melting point of 170 ° C or lower.   The core-sheath conjugate fiber according to any one of claims 1 to 3, wherein the thermoplastic polymer of the sheath part has a melting point of 240 ° C or higher.   The core-sheath composite according to any one of claims 1 to 4, wherein the thermoplastic polymer of the sheath is a polyester polymer in which a main repeating unit is composed of a repeating unit of polyethylene terephthalate. fiber.   The core-sheath conjugate fiber according to any one of claims 1 to 5, wherein a mass composite ratio of the core part and the sheath part is 5:95 to 40:60.   The core-sheath conjugate fiber according to any one of claims 1 to 6, wherein the cross-sectional shape is a concentric circle shape.   A fiber structure containing 10 wt% or more of the core-sheath conjugate fiber according to any one of claims 1 to 7.