JP2019007118A - False twisted multifilament yarn, manufacturing method thereof, and woven/knitted fabrics - Google Patents

Abstract

To provide a false twisted multifilament yarn from which woven/knitted fabrics excellent in heat shielding can be made, the yarn being suitably used in manufacturing bulky woven/knitted fabrics.SOLUTION: A false twisted multifilament yarn comprises a polyester resin containing inorganic oxide particles. The false twisted multifilament yarn includes hollow monofilaments with a hollow part compressed to a hollowness of less than 3%, at a proportion of 95% or more.SELECTED DRAWING: None

Description

  The present invention relates to a false-twisted multifilament yarn that is excellent in heat shielding properties by exhibiting infrared reflectivity when made into a woven or knitted fabric, and that can be suitably used for producing a bulky woven or knitted fabric, and a method for producing the same. Furthermore, the present invention relates to a bulky woven or knitted fabric including false twisted multifilament yarn.

  Polyester fibers are excellent in dimensional stability, durability, and the like, and are therefore preferably used as woven or knitted fabrics in a wide range of fields such as clothing, industrial use, and medical use. For example, in the knitted and knitted fabrics used in the clothing field, while the market demands weight reduction and thinning, clothing that shields sunlight and the like irradiated under hot weather in summer is required.

  A polyester fiber containing inorganic fine particles (for example, titanium oxide fine particles) is known as a fiber for obtaining a woven or knitted fabric having excellent heat shielding properties. However, when the inorganic fine particles are contained in the polyester fiber at a high concentration so as to further improve the heat shielding property, many inorganic fine particles are exposed on the surface of the fiber. The exposed inorganic fine particles cause guide wear and the like at the time of spinning, so that the spinning property is lowered.

  In order to solve the above problems, there is provided a polyester-based sheath-sheath composite fiber in which a core portion containing a high concentration of inorganic fine particles and a sheath portion containing a low concentration of inorganic fine particles are arranged concentrically. Are known. However, in such a core-sheath type composite fiber, although the yarn-making property is improved, the heat-shielding property when made into a woven or knitted fabric is insufficient.

  Therefore, various studies have been conducted on the cross-sectional shape of the polyester fiber containing inorganic fine particles in order to improve the heat-shielding property when the knitted or knitted fabric is used. Specifically, it is known to have a multi-leaf shape having 6 to 10 leaf portions (see Patent Document 1) or to have a flat cross-sectional shape (see Patent Document 2). However, even if the technique described in Patent Document 1 is used, it is necessary to increase the concentration of the inorganic fine particles in the core, so that the sheath is broken and the core is exposed on the fiber surface. Moreover, even if it is a case where the technique described in patent document 2 is used, the density | concentration of an inorganic fine particle cannot be made low enough. That is, even in Patent Documents 1 and 2, only fibers with insufficient yarn-making properties and heat shielding properties in the case of woven or knitted fabric can be obtained.

  On the other hand, in order to solve the above-mentioned problem of the yarn forming property with respect to the concentration of inorganic fine particles, false twisted hollow multifilament yarns that have been false twisted under specific conditions so as to maintain a desired hollow portion are known. (Patent Document 3). The knitted or knitted fabric using the false-twisted hollow multifilament yarn of Patent Document 3 effectively exhibits light reflection and refraction even when the content of inorganic fine particles is sufficiently reduced, and is excellent in heat shielding properties.

JP 2008-086863 A JP2013-044055A Japanese Patent Laid-Open No. 2006-113714

  The false twisted hollow multifilament yarn of Patent Document 3 needs to be provided with a predetermined hollow portion in a single fiber in order to exhibit excellent heat shielding properties. For this reason, the false twist hollow multifilament yarn of patent document 3 is manufactured by performing false twist processing under conditions of low temperature and low false twist coefficient. Therefore, the false twisted hollow multifilament yarn has a problem that it has low crimpability and is not suitable for use in producing a woven or knitted fabric having a high bulk and good texture.

  The present invention provides a false twisted multifilament yarn that is further improved from such a conventional technique and has excellent heat shielding properties when used as a woven or knitted fabric, and can be suitably used for the production of a bulky woven or knitted fabric. Main purpose. Furthermore, this invention also aims at providing the manufacturing method of the said false twist multifilament yarn, and the woven / knitted fabric containing the said false twist multifilament yarn.

  The present inventors have intensively studied to solve the above problems. As a result, a false twisted multifilament yarn made of a polyester resin containing inorganic oxide particles, wherein the hollow portion of the hollow fiber is compressed and the proportion of single fibers having a hollowness of less than 3% is 95% or more. It has been found that the twisted multifilament yarn is excellent in heat-shielding properties when made into a woven or knitted fabric, can impart a high crimp rate, and is suitable for the production of a woven or knitted fabric that is bulky and has a good texture.

  More specifically, the present inventors examined in detail the relationship between the false twisting conditions and the hollow ratio after false twisting in the false twisted multifilament yarn, the crimp ratio, and the effect on the heat shielding property. As a result, contrary to the conventional knowledge that excellent heat-insulating properties cannot be exhibited unless a woven or knitted fabric using a false twisted hollow multifilament yarn having a predetermined hollow portion in a single fiber, the hollow multifilament yarn is hollow. The false twisted multifilament yarn that has been subjected to false twist processing in which the portion is greatly compressed and the ratio of single fibers having a hollowness ratio of less than 3% is 95% or more is the false twisted hollow multi yarn disclosed in Patent Document 3 As in the case of filament yarn, an unexpected finding has been obtained that when it is made into a woven or knitted fabric, it has excellent heat shielding properties. It is considered that this is because the discontinuous portion of the polyester resin is formed in the portion where the hollow portion of the single fiber is crushed, and light reflection and refraction are effectively expressed.

  Furthermore, even with false twisted multifilament yarns containing 95% or more of single fibers having a hollow ratio of less than 3%, which are subjected to false twist processing in which the hollow portion is greatly compressed, it is clear that excellent heat shielding properties are exhibited. Therefore, the conditions of false twisting to obtain false twisted multifilament yarns are higher than those of false twisting which suppresses the crushing of the hollow portion of the single fiber. Since the conditions for twisting can be selected, it has been found that false twisted multifilament yarns can be obtained that can be suitably used for the production of woven and knitted fabrics that are bulky and have a good texture in addition to excellent heat shielding properties.

  That is, the present inventors have a ratio of single fibers in which the hollow portion of the hollow fiber constituting the hollow multifilament yarn is compressed by the false twisting process and the hollow ratio is less than 3% is 95% or more. A certain false twisted multifilament yarn was found to be excellent in heat-shielding properties when made into a woven or knitted fabric, and suitable for the production of a woven or knitted fabric having a bulky and good texture.

  The present invention has been completed by further studies based on these findings.

That is, this invention provides the invention of the aspect hung up below.
Item 1. A false twist multifilament yarn comprising a polyester resin containing inorganic oxide particles,
The false twisted multifilament yarn is a false twisted multifilament yarn in which the hollow portion of the hollow fiber is compressed and the proportion of single fibers having a hollowness of less than 3% is 95% or more.
Item 2. Item 2. The false-twisted multifilament yarn according to Item 1, wherein the crimped rate of the false-twisted multifilament yarn is 35% or more.
Item 3. Item 3. The false-twisted multifilament yarn according to Item 1 or 2, wherein the content of the inorganic oxide particles in the polyester resin is 10% by mass or less.
Item 4. Item 5. The false-twisted multifilament yarn according to any one of Items 1 to 3, wherein the single fiber has a fineness of 0.5 to 2.5 dtex.
Item 5. In the hollow fiber, the content X (mass%) of the inorganic oxide particles is 2 <X ≦ 10, and the content Y (mass%) of the inorganic oxide particles is 2 mass% or less. Segment B,
Item 5. The false-twisted multifilament yarn according to any one of Items 1 to 4, wherein a shape of a cross section with respect to a longitudinal direction of the hollow fiber further satisfies the following (1) to (5).
(1) The shape of the segment A in the cross section is a multi-leaf shape including 6 to 30 leaf portions radially extending from the center side to the outer peripheral side of the hollow fiber.
(2) The distal end portion on the outer peripheral side of the leaf portion has a curved shape.
(3) The ratio of the exposed length (μm) of the segment A to the hollow fiber surface with respect to the outer peripheral length (μm) of the hollow fiber is 10% or less.
(4) The average ratio of the shortest distance (μm) from the outer periphery of the hollow fiber to the leaf part to the distance (μm) from the center of the hollow fiber to the outer periphery of the hollow fiber is 10% or less.
(5) The hollow ratio of the hollow fiber is 5 to 30%.
Item 6. Preparing a hollow multifilament yarn made of a polyester resin containing inorganic oxide particles;
A step of subjecting the hollow multifilament yarn to false twisting so that the proportion of single fibers having a hollowness of less than 3% is 95% or more;
A process for producing false twisted multifilament yarn.
Item 7. In the hollow multifilament yarn, the content X (mass%) of the inorganic oxide particles is 2 <X ≦ 10, and the content Y (mass%) of the inorganic oxide particles is 2 mass% or less. A hollow fiber having a segment B which is
The manufacturing method of false twist multifilament yarn in which the shape of the cross section with respect to the longitudinal direction of the hollow fiber further satisfies the following (1) to (5).
(1) The shape of the segment A in the cross section is a multi-leaf shape including 6 to 30 leaf portions radially extending from the center side to the outer peripheral side of the hollow fiber.
(2) The distal end portion on the outer peripheral side of the leaf portion has a curved shape.
(3) The ratio of the exposed length (μm) of the segment A to the hollow fiber surface with respect to the outer peripheral length (μm) of the hollow fiber is 10% or less.
(4) The average ratio of the shortest distance (μm) from the outer periphery of the hollow fiber to the leaf part to the distance (μm) from the center of the hollow fiber to the outer periphery of the hollow fiber is 10% or less.
(5) The hollow ratio of the hollow fiber is 5 to 30%.
Item 8. Item 6. A woven or knitted fabric comprising the false-twisted multifilament yarn according to any one of Items 1 to 5.
Item 9. Item 9. The woven or knitted fabric according to Item 8, wherein the average infrared reflectance at a wavelength of 700 to 1200 nm is 60% or more.

  ADVANTAGE OF THE INVENTION According to this invention, the false twist multifilament yarn which is excellent in the heat-shielding property at the time of setting it as a woven / knitted fabric, and can be used suitably for manufacture of a woven / knitted fabric with a sufficient bulky texture can be provided. Moreover, according to this invention, it aims also at the manufacturing method of the said false twist multifilament yarn, and providing the woven / knitted fabric containing the said false twist multifilament yarn.

It is a schematic diagram which illustrates embodiment of the cross-sectional shape with respect to the longitudinal direction of the hollow fiber used for manufacture of the false twist multifilament yarn of this invention. It is a cross-sectional photograph of the false twist multifilament yarn of Example 1 (580 times). It is a cross-sectional photograph of the false twist multifilament yarn of the comparative example 1 (580 times).

  Hereinafter, the false twisted multifilament yarn of the present invention, the manufacturing method thereof, and the woven or knitted fabric using the false twisted multifilament yarn will be described in detail.

(False twist multifilament yarn)
The false-twisted multifilament yarn of the present invention is a false-twisted multifilament yarn made of a polyester resin containing inorganic oxide particles, and the hollow portion of the hollow fiber is compressed and the hollow ratio is less than 3%. The ratio is 95% or more. The false-twisted multifilament yarn of the present invention has such a configuration, so that it has excellent heat shielding properties when made into a woven or knitted fabric, and can impart a high crimp rate, which is bulky and has a good texture. It can use suitably for manufacture of a woven / knitted fabric.

  As the inorganic oxide particles contained in the polyester resin, those having a high sunlight shielding effect are suitable, and examples thereof include fine particles such as titanium oxide, calcium oxide, magnesium oxide, and zinc oxide. Among these, titanium oxide fine particles are preferable.

  Further, the titanium oxide fine particles may be a rutile type or an anatase type. Titanium oxide fine particles are preferable because they are superior in heat shielding properties or versatility and have high cost merit compared to other inorganic fine particles (for example, calcium oxide, magnesium oxide, or zinc oxide fine particles).

  Although it does not restrict | limit especially as an average particle diameter of an inorganic oxide particle, Preferably it is about 0.1-3.0 micrometers from a viewpoint of improving heat insulation effectively. In particular, since the titanium oxide fine particles are used as a so-called concealing material, it is preferable to have a particle size that can efficiently reflect light rays from visible rays to infrared rays. The average particle diameter of the titanium oxide fine particles is preferably about 0.1 to 3.0 μm. Here, the average particle diameter of the inorganic oxide particles (titanium oxide fine particles) is determined by measuring the diameter of, for example, 100 or more particles with an electron microscope and calculating the average value.

  The content of the inorganic oxide particles in the polyester resin constituting the false twisted multifilament yarn is not particularly limited, but is preferably 10 from the viewpoint of exhibiting excellent heat shielding properties while suppressing guide wear and the like. The mass% or less, More preferably, about 0.01-10 mass%, More preferably, about 0.01-5 mass%, More preferably, about 1-3 mass% is mentioned. In the false-twisted multifilament yarn of the present invention, as will be described later, the hollow portion of the hollow fiber is compressed by subjecting the hollow multifilament yarn to false twisting, and the proportion of single fibers having a hollowness of less than 3% Is over 95%. For this reason, even if the content of the inorganic oxide particles is low, excellent heat shielding properties can be exhibited due to the discontinuous portion of the resin formed by crushing the hollow portion. Moreover, since the false twisted multifilament yarn of the present invention can be manufactured under conditions in which the hollow portion is crushed by false twisting, it is excellent in spinning operability or process passability.

  The inorganic oxide particles may be uniformly dispersed in the polyester resin, or a high concentration portion and a low concentration portion of the inorganic oxide particles may exist in the polyester resin. In addition, in the polyester resin, those having a high concentration portion and a low concentration portion of the inorganic oxide particles, for example, a hollow multifilament yarn composed of a hollow fiber S described later, for false twisting It can form by providing. As described later, in the hollow fiber S, for example, the shape of the segment A in which the content X (mass%) of the inorganic oxide particles is 2 <X ≦ 10 in the cross section with respect to the longitudinal direction of the hollow fiber is hollow fiber. It has a multi-leaf shape including 6 to 30 leaf portions that radiate from the center side to the outer periphery side.

  Specific examples of the polyester resin include resins made of polyester such as polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polyoxyethoxybenzoate, polyethylene naphthalate, and cyclohexanedimethylene terephthalate. Alternatively, these polyesters may be copolymerized with an isophthalic acid, sulfoisophthalic acid component, or diol component (for example, propylene glycol, butylene glycol, cyclohexane dimethanol, or diethylene glycol) as an additional portion, or aliphatic polyester (polylactic acid). And a compound such as polybutylene succinate which is decomposed into carbon dioxide and water by the action of microorganisms when left in soil or water for a long time. Among these, polyethylene terephthalate is preferable. The polyester resin contained in the false twisted multifilament yarn may be one type or two or more types.

  In the false-twisted multifilament yarn of the present invention, the ratio of the single fiber having a hollowness of less than 3% is not particularly limited as long as it is 95% or more, but has excellent heat shielding properties when made into a woven or knitted fabric, and is bulky. From the viewpoint of making a false-twisted multifilament yarn that can be suitably used for the production of a woven or knitted fabric, it is preferably 97% or more, more preferably 99% or more, and even more preferably 100%. The ratio of single fibers having a hollow ratio of less than 3% means the ratio of the total number of single fibers having a hollow ratio of less than 3% in the total number of single fibers contained in the false twisted multifilament yarn. Yes. For example, when the total number of single fibers included in the false twisted multifilament yarn is 100, and the total number of single fibers having a hollowness of less than 3% is 50, the hollowness is 3%. The proportion of less than single fibers is 50%. When the number of single fibers contained in the false-twisted multifilament yarn is less than 100, it is converted to a numerical value per 100.

  In particular, in the false twisted multifilament yarn of the present invention, the hollowness is 0 from the viewpoint of providing a false twisted multifilament yarn that is excellent in heat shielding when made into a woven or knitted fabric and can be suitably used for the production of a bulky woven or knitted fabric. % Of single fibers is preferably 95% or more, more preferably 97% or more, still more preferably 99% or more, and particularly preferably 100%.

  The false twist multifilament yarn of the present invention is obtained by false twisting a hollow multifilament yarn composed of a plurality of hollow fibers. The false-twisted multifilament yarn of the present invention has a ratio of single fibers having a hollow ratio of less than 3%, which is as large as 95% or more. However, since the hollow portion of the hollow fiber has a portion that is compressed and crushed, Without excessively increasing the content of oxide particles, reflection and refraction of light at a discontinuous portion of the resin in the collapsed portion of the single fiber and sufficient gap between the single fibers constituting the woven or knitted fabric A false twisted multifilament yarn that exhibits the phenomenon effectively and has excellent heat shielding properties when formed into a woven or knitted fabric can be obtained.

  From the viewpoint of providing a false twisted multifilament yarn that is excellent in heat-shielding properties when made into a woven or knitted fabric and can be suitably used for the production of a bulky woven or knitted fabric, the false twist is 3 in the false twisted multifilament yarn of the present invention. The ratio of the single fibers of not less than% is preferably less than 2%, more preferably 1% or less, and still more preferably 0%.

  In addition, the hollow ratio of the single fiber which comprises false twist multifilament yarn is the value measured with the following measuring methods. The hollow ratio of the hollow fibers constituting the hollow multifilament yarn is also measured in the same manner.

<Hollow rate>
The cross section of the false-twisted multifilament yarn was taken with an optical microscope at a magnification of 580 times. From this cross-sectional photograph, the proportion of single fibers having a hollow ratio of less than 3% (number of fibers) for each single fiber Count and ask. When the number of single fibers contained in the false twisted multifilament yarn is less than 100, the ratio (number%) is calculated in terms of a numerical value per 100. Details of the measurement method are as described in the examples.

  From the standpoint of a false twisted multifilament yarn that is excellent in heat-shielding properties when made into a woven or knitted fabric, and can be suitably used for the production of a bulky woven or knitted fabric, the hollow portion of the hollow fiber is compressed and crushed The part is preferably located at the center of the single fiber. Since the portion where the hollow portion of the hollow fiber is compressed and crushed is located at the center of the single fiber, the strength of the false twisted multifilament yarn can be maintained.

  The crimp rate of the false twisted multifilament yarn of the present invention is not particularly limited, but is excellent in heat-shielding properties when made into a woven or knitted fabric, and can further be suitably used for producing a bulky woven or knitted fabric From the viewpoint of obtaining a yarn, it is preferably 35% or more, more preferably 50% or more. An example of the upper limit of the crimp rate is 80%. The crimping rate of the false twisted multifilament yarn can be adjusted by controlling the conditions (for example, heater temperature, overfeed rate, false twisting factor) when false twisting the hollow multifilament yarn.

  The crimp rate of the false twisted multifilament yarn is a value measured by the following measuring method.

<Crimping rate>
The crimp rate is calculated from the following formula (I). The load is a load applied in a state where the yarn is skeined and then skeined into a ring.
Crimp rate (%) = {(A0−A1) / A0} × 100 (I)
A1: The yarn is skeined while applying a tension of 90.91 × 10 ⁻³ cN / dtex to the yarn, and left to stand for 30 minutes under a load of 1.47 × 10 ⁻⁴ cN / dtex. And a boiling water treatment for 30 minutes under a load of 1.47 × 10 ⁻⁴ cN / dtex. After treatment, wipe the water off and leave it for 30 minutes or more. Remove the load of 1.47 × 10 ⁻⁴ cN / dtex and apply the load of 1.76 × 10 ⁻³ cN / dtex. It is long.
A0: A skein length when the load is changed from 1.76 × 10 ⁻³ cN / dtex to 4.41 × 10 ⁻² cN / dtex after measurement of A1.

  Although it does not restrict | limit especially as the fineness of the single fiber which comprises the false twist multifilament yarn of this invention, Preferably it is about 0.5-2.5 dtex, More preferably, about 0.8-2.3 dtex is mentioned. When the fineness of the single fiber is 2.5 dtex or less, for example, when the number of filaments is increased, the total fineness does not become too thick, and in addition, the woven or knitted fabric can be thinned. The surface coverage is improved. On the other hand, when it is 0.5 dtex or more, since the portion where the hollow portion of the hollow fiber is compressed can be formed in the center portion of the single fiber, heat insulation and strength are excellent.

  The shape of the single fiber constituting the false-twisted multifilament yarn of the present invention is not particularly limited, and may be a round cross section, or an irregular cross section such as a triangle, a quadrangle, or a multileaf shape.

  The elongation of the false-twisted multifilament yarn of the present invention is likely to change the physical properties of the false-twisted multifilament yarn due to the tension that is inevitably applied in post-processing (for example, a series of processing including dyeing). For example, 20 to 35% is preferable because it may cause trouble in terms of quality of the woven or knitted fabric.

  The single fiber constituting the false-twisted multifilament yarn has various additives (for example, pigments, dyes, colorants, water repellents, water absorbents, flame retardants) as necessary, as long as the effects of the present invention are not impaired. , Stabilizers, antioxidants, ultraviolet absorbers, crystal nucleating agents, lubricants, plasticizers, antibacterial agents, or fragrances). When an additive is contained in the single fiber, the content can be appropriately selected within a range not impairing the effects of the present invention.

  In the false twist multifilament yarn of the present invention, it is preferable that the false twist multifilament yarn has a larger number of filaments in order to enhance the diffuse reflection effect of sunlight when it is made into a woven or knitted fabric. Specifically, the number of filaments is preferably 10 to 200, more preferably 20 to 120. When the number of filaments is 10 or more, the total number of portions where the hollow portion of the hollow fiber is compressed and crushed is increased, so that the heat shielding property is more excellent. On the other hand, when the number of filaments is 200 or less, the strength of false twisted multifilament yarns is not too weak, and when woven or knitted, defects such as fuzz due to pilling or single yarn breakage during friction are suppressed. it can.

  In the false-twisted multifilament yarn of the present invention, the hollow fiber used for the formation of the single fiber includes the segment A in which the content ratio X (mass%) of the inorganic oxide particles is 2 <X ≦ 10, and the content of the inorganic oxide particles A hollow fiber having a segment B having a rate Y (% by mass) of 2% by mass or less (hereinafter sometimes referred to as “hollow fiber S”) is preferable. Furthermore, it is preferable that the shape of the cross section with respect to the longitudinal direction of the hollow fiber S satisfies the following (1) to (5).

(1) The shape of the segment A in the cross section is a multi-leaf shape including 6 to 30 leaf portions radially extending from the center side to the outer peripheral side of the hollow fiber.
(2) The distal end portion on the outer peripheral side of the leaf portion has a curved shape.
(3) The ratio of the exposed length (μm) of the segment A to the hollow fiber surface with respect to the outer peripheral length (μm) of the hollow fiber is 10% or less.
(4) The average ratio of the shortest distance (μm) from the outer periphery of the hollow fiber to the leaf part to the distance (μm) from the center of the hollow fiber to the outer periphery of the hollow fiber is 10% or less.
(5) The hollow ratio of the hollow fiber is 5 to 30%.

  In the hollow fiber S, the segment A needs to have an inorganic oxide particle content X (mass%) of 2 <X ≦ 10, preferably 3 ≦ X ≦ 8, and more preferably 5 ≦ X ≦ 8. preferable.

  On the other hand, the segment B requires that the content Y (% by mass) of the inorganic oxide particles is 2% by mass or less, from the viewpoint of coexistence of the spinning operability and the heat shielding effect as a woven or knitted fabric, 0 <Y ≦ 1 is preferable, and 0 <Y ≦ 0.5 is more preferable.

  It is preferable that the shape of the segment A in the cross section with respect to the longitudinal direction of the hollow fiber S is a multi-leaf shape including 6 to 30 leaf portions radially extending from the center side to the outer peripheral side of the hollow fiber S, and 8 to 25 More preferably, it has a multi-leaf shape including individual leaf portions.

  Here, the leaf portion means a shape such as a substantially rectangular shape, a substantially elliptical shape, a substantially trapezoidal shape, etc., and at least one corner is a curve. Specifically, for example, the multifilament yarn shown in FIG. This is exemplified by the cross-sectional shape with respect to the longitudinal direction of the hollow fiber (hereinafter sometimes abbreviated as the composite shape of the present invention). In addition, the leaf portion does not need to be smooth on each side in, for example, a substantially rectangular shape, a substantially oval shape, or a substantially trapezoidal shape. For example, the leaf portion has a minute convex portion and / or a concave portion or a wavy line. May be.

  In addition, as illustrated in FIGS. 1A to 1D, in the composite shape of the hollow fiber S, the segment A has a leaf portion radially extending from the center side of the hollow fiber 1 to the outer peripheral side. The parts 4 may exist separately in the segment B (for example, FIGS. 1 (a), (c) and (d)), or may be connected to each other in the segment B (for example, FIG. 1). (B)). Moreover, a part may be connected among 6-30 leaf parts, and the remainder may exist separated by segment B.

  As described above, as the segment A, when the leaves are separated in the segment B, the interval between the adjacent leaves is preferably 0.1 to 2.0 μm, More preferably, it is 1.0 μm.

  Since the shape of the segment A in the cross-section of the hollow fiber S is a multi-leaf shape including 6 to 30 leaf portions radially extending from the center side of the hollow fiber S to the outer peripheral side, The interval can be small. Further, preferably, by setting the interval to be a specific one, it is easy to repeat that the sunlight that has entered one of the leaf portions and diffusely reflected is further diffusely reflected by the adjacent leaf portions.

  Moreover, it is preferable that the front-end | tip part of the outer peripheral side is a curve shape. When the tip has a curved shape, the heat shielding effect is more excellent when a woven or knitted fabric is formed. This is presumed to be caused by the fact that sunlight incident on the multifilament causes diffuse reflection by collapsing the tip of the curved leaf portion into an irregular shape. Furthermore, when the tip is curved, even when false twisting is performed, the segment A becomes difficult to jump out to the fiber surface, and the inorganic oxide particles are not exposed. Can be suppressed.

  In the composite shape, the hollow fiber S preferably has a ratio (EC) of the exposed length (μm) of the segment A to the surface of the hollow fiber S with respect to the outer peripheral length (μm) of the hollow fiber S being 10% or less. The following is more preferable. When EC satisfies such an upper limit, the tip of the leaf portion which is a curved shape is crushed into an irregular shape, and the sunlight incident on the multifilament causes diffuse reflection and becomes a woven or knitted fabric. In addition, the heat shielding effect is more excellent.

  Further, by setting the EC to 10% or less, the processability in the spinning operability, the yarn making process, and the weaving / knitting process is improved.

  The hollow fiber S is an average ratio of the shortest distance (μm) from the outer periphery of the hollow fiber S to the leaf part with respect to the distance (μm) from the center of the hollow fiber S to the outer periphery of the hollow fiber S in each leaf part of the composite shape. (DC) is preferably 10% or less, and more preferably 5% or less. When the DC satisfies such an upper limit, the tip of the curved leaf portion is crushed into an irregular shape, and the sunlight incident on the multifilament causes diffuse reflection, resulting in a woven or knitted fabric. In addition, the heat shielding effect is more excellent.

  The EC and DC can be adjusted to the above ranges by appropriately adjusting the spinning conditions such as the shape of the spinning nozzle, the viscosity of the synthetic resin, and the spinning temperature.

  Furthermore, the hollow ratio of the hollow fiber S is preferably about 5 to 30%, and more preferably about 10 to 20%. The hollow ratio can be adjusted to the above range by appropriately adjusting the spinning conditions such as the shape of the spinning nozzle, the viscosity of the synthetic resin, and the spinning temperature. The hollow ratio of the hollow fiber S is a value calculated from the area ratio of the hollow fiber by measuring the radius of the hollow fiber and the radius of the hollow part from the cross-sectional photograph of the hollow fiber, calculating the area of the cross section of the hollow fiber and the area of the hollow part. It is. The details of the method for measuring the hollow ratio of the hollow fiber are as described in the examples. In addition, the said hollow rate of the hollow fiber S is calculated by the average value of 20 pieces.

  In the composite shape of the hollow fiber S, the shape of the segment A is preferably rotationally symmetric. Here, the rotationally symmetric shape refers to a shape that overlaps the original shape when rotated by a certain angle around the center point of the cross section of the hollow fiber S. Since the shape of the segment A is rotationally symmetric, the hollow fiber S spun from the spinning nozzle exhibits a so-called yarn bending phenomenon, and there is a problem that stable spinnability and good yarn quality cannot be obtained. It becomes difficult to do. In addition, it is difficult for the segment A to be shielded, and uniform heat shielding properties can be easily obtained for all angles.

  In the hollow fiber S, the mass ratio (segment A / segment B) between the segment A and the segment B is preferably 30/70 to 90/10, and more preferably 60/40 to 80/20. .

  When the mass ratio of the hollow fibers S is 30/70 or more, the false-twisted multifilament yarn of the present invention is particularly excellent in heat shielding properties when used as a woven or knitted fabric. When the mass ratio is 90/10 or less, the processability in the spinning operability, the spinning process, and the weaving and knitting process is easily improved. When the mass ratio of the hollow fiber S is 60/40 to 80/20, the false twisted multifilament yarn of the present invention has good processability in spinning operability, yarn making process, and weaving and knitting process, It is more preferable in that the knitted or knitted fabric is particularly excellent in heat shielding properties.

  Although the manufacturing method in particular of the false twist multifilament yarn of this invention is not restrict | limited, For example, it can manufacture suitably with the following method.

(Manufacturing method of false twist multifilament yarn)
The manufacturing method of the false twist multifilament yarn of the present invention includes the following steps.
Step of preparing a hollow multifilament yarn comprising a polyester resin containing inorganic oxide particles The hollow multifilament yarn is false twisted so that the proportion of single fibers having a hollowness of less than 3% is 95% or more. Process to be used for

  That is, the false twisted multifilament yarn of the present invention is subjected to false twisting so that the ratio of single fibers having a hollowness of less than 3% is 95% or more with respect to the hollow multifilament yarn. .

  In the false twisted multifilament yarn manufacturing method of the present invention, first, a hollow multifilament yarn made of a polyester resin containing inorganic oxide particles is prepared. The kind and content of the inorganic oxide particles contained in the hollow multifilament yarn correspond to the false twisted multifilament yarn of the present invention described above.

  Moreover, the preferable fineness of the hollow fiber constituting the hollow multifilament yarn also corresponds to the fineness of the single fiber constituting the false twisted multifilament yarn. When the fineness of the hollow fiber is 0.5 dtex or more, troubles such as fluff generation in post-processing are unlikely to occur. Moreover, since the number of single fibers with respect to the same fineness can be increased as the fineness of the hollow fiber is 3.5 dtex or less, the woven or knitted fabric can exhibit more excellent heat shielding properties.

  The hollow ratio of the hollow fiber constituting the hollow multifilament yarn that is the raw yarn of the false twisted multifilament yarn of the present invention is preferably about 5 to 30%, more preferably about 5 to 15%. When the hollow ratio of the hollow fiber before false twisting is in the range of 5 to 30%, in the single fiber after false twisting, the portion where the hollow part is compressed and becomes discontinuous is sufficiently large, and the woven or knitted fabric The heat-shielding property is further improved.

  As a hollow multifilament yarn subjected to false twisting, a drawn yarn (SDY or FDY) may be used, or a highly oriented undrawn yarn (POY) may be used. When used, by adjusting the draw ratio in a general drawing simultaneous false twisting method, it is possible to obtain false twisted multifilament yarns equivalent to the case of using drawn yarns, and to reduce costs. The drawn yarn includes one having an elongation of about 20 to 80% and a birefringence of about 0.170 to 0.300, and the highly oriented undrawn yarn has an elongation of about 80 to 250%. And those having a birefringence of about 0.025 to 0.050.

  Furthermore, in the false twisted multifilament yarn manufacturing method of the present invention, the hollow fiber constituting the hollow multifilament yarn may include the hollow fiber S described above, or only the hollow fiber S. Also good. The details of the hollow fiber S are as described above.

  Next, the hollow multifilament yarn is subjected to a false twisting process so that the ratio of single fibers having a hollowness of less than 3% is 95% or more.

  The false twisting method is generally divided into a spindle method and a friction method. In the present invention, any of these methods can be adopted. Generally, as the false twisting tool, a pin type is used for the spindle method, and a disk type is used for the friction method.

  From the viewpoint of performing false twisting so that the proportion of single fibers having a hollowness of less than 3% is 95% or more, in the process of subjecting to false twisting, the hollow multifilament yarn described above is used when the spindle method is used. Is preferably twisted under the conditions of a temperature of 170 to 230 ° C. (preferably 180 to 220 ° C.) and a false twist coefficient of 23,000 to 35,000 (preferably 25,000 to 30,000).

  Thus, false twisted multifilament yarn having a hollow portion crushed at the center of a single fiber is subjected to false twisting under the false twisting conditions as described above. Therefore, as described above, there is a sufficient gap between the single fibers constituting the woven or knitted fabric and a discontinuous portion at the center of the single fiber without excessively increasing the content of the titanium oxide fine particles. In addition, the false twisted multifilament yarn can be made to exhibit the light reflection and refraction phenomenon more appropriately and has a significantly excellent heat shielding property. Moreover, the false twist multifilament yarn with a higher crimp rate is obtained by performing false twist processing under the false twist processing conditions as described above.

  When the false twisting temperature is 170 ° C. or higher in the false twisting process employing the spindle method, sufficient crimps are easily obtained with the false twisted multifilament yarn obtained. Moreover, by being 230 degrees C or less, it is hard to fuse | melt fibers together, generation | occurrence | production of the fault at the time of making a fiber fully open and making it into a fabric can be suppressed.

  Further, in the false twisting process employing the spindle method, the false twist coefficient is 23,000 or more, so that the false twisted multifilament yarn can be sufficiently crimped. On the other hand, when the false twisting coefficient is 35,000 or less, yarn breakage can be suppressed and false twisted multifilament yarns with less fluff can be obtained.

  In the false twist multifilament yarn manufacturing method of the present invention, other false twist processing conditions are not particularly limited as long as the effects of the present invention are not impaired. For example, when a drawn yarn is used as a false twist raw yarn The draw ratio is preferably 0.9 to 1.2 times, more preferably 1.0 to 1.1 times. In the case of drawn yarn, the overfeed rate is preferably -2% to 5%. The twisting tension is preferably about 1/20 to 1/5 (g) with respect to the fineness of the drawn yarn, and the twisting / untwisting ratio expressed by untwisting tension / twisting tension is 1.5-3. About 0.0 is preferable.

  When the drawn yarn is false twisted, if the draw ratio is 0.9 times or less and the overfeed rate is 5% or more, loosening occurs during false twisting, which may cause the yarn to wind around the roller or cause yarn breakage. Can be. On the other hand, if the draw ratio is 1.2 times or more and the overfeed rate is -2% or less, the yarn physical properties such as fineness and elongation of the false twisted multifilament yarn may change.

  When the drawn yarn is false twisted, if the twisting tension is 1/20 (g) or more with respect to the fineness of the drawn yarn, the occurrence of loosening during false twisting is suppressed and the yarn is wound around the roller. And the factor of thread breakage can be reduced. On the other hand, when the twisting tension is 1/5 (g) or less of the fineness of the drawn yarn, it suppresses the deterioration of operability such as yarn breakage during false twisting, and reduces the occurrence of fluff due to filament breakage. obtain.

  Further, the twisting / untwisting ratio represented by the untwisting tension / twisting tension is preferably about 1.5 to 3.0 in order to make the above twisting tension range.

  In the false twisted multifilament yarn manufacturing method of the present invention, when a highly oriented undrawn yarn is used as a false twisted multifilament yarn, a general spindle method is used as the false twist method in the simultaneous drawing false twisting process. Alternatively, a friction method may be used.

  When the friction method is adopted, the false twisting temperature is preferably in the range of about 170 to 200 ° C. for the contact heater and about 200 to 350 ° C. for the point contact heater. If the false twisting temperature is below the above range, sufficient crimps are difficult to be imparted, and if the false twisting temperature is above the above range, the fibers are likely to be fused together, and the fibers are not sufficiently opened.

  In the friction system, in general, the degree of twist is not managed by the false twist coefficient, but by the K value and the number of disks. This is due to the difference between both types of twisting and untwisting mechanisms. K value means the ratio (F2 / F1) of untwisting tension (F2) and twisting tension (F1). F2 is the yarn tension immediately after passing through the disk, and F1 is introduced into the disk. The last thread tension. In the friction system, twist is applied by the rotation of the disk. Therefore, the degree of twisting is determined by the disk speed (D) and the number of disks.

  D / Y refers to the ratio (D / Y) between the disk speed (D) and the processing speed (Y), and the range of D / Y is generally preferably 1.5 to 2.2. By increasing the numerical value, it is possible to decrease the K value.

  However, since managing the disk speed directly is not very efficient in process management, it is generally efficient to manage the K value in view of the fact that the K value fluctuates due to fluctuations in the disk speed. It is said that there is.

  In the friction system, a disk made of polyurethane is generally used. In general, the number of disks is preferably 5 to 7, and the thickness of the disk is preferably 5 to 10 mm. Moreover, as K value, 0.6-1.2 are preferable. When the K value is less than 0.6, yarn breakage increases, and false twisted yarn with a lot of fluff may be obtained. On the other hand, if it exceeds 1.2, surging tends to occur. Surging refers to a state in which the twisted twist is not unwound in the untwisted region and the twist remains.

(Weaving and knitting)
The woven or knitted fabric of the present invention includes the false twisted multifilament yarn of the present invention. The woven or knitted fabric of the present invention is excellent in heat shielding properties. The woven or knitted fabric of the present invention preferably contains the false twisted multifilament yarn of the present invention at a mixing ratio of 30% by mass or more, and more preferably includes a mixing ratio of 50% by mass or more. When the mixing ratio is 30% by mass or more, the woven or knitted fabric is more excellent in heat shielding properties. Furthermore, since the false twisted multifilament yarn of the present invention can impart a high crimp rate, a woven or knitted fabric having excellent bulkiness and good texture can be obtained. Examples of the mixing method include mixed fiber, mixed spinning, knitting, knitting, and knitting.

  In the woven or knitted fabric of the present invention, the location where the false twisted multifilament yarn is used is not particularly limited, and may be used for either the front surface or the back surface.

  When the woven or knitted fabric of the present invention is a woven fabric, specific examples of the structure include plain weave, twill weave, satin weave, and entangled weave. As the fabric density, the warp density is preferably 150 yarns / inch or more, and the weft density is preferably 70 yarns / inch or more. When the warp density or the weft density is within this range, the voids between the constituent fibers in the woven fabric are not excessively increased, and the heat shielding property is excellent.

  In the case where the woven or knitted fabric of the present invention is a knitted fabric, specific examples of the structure include canoco, milling or smooth. As the knitted fabric density, a value of (number of courses per inch) × (number of wales per inch) is preferably 1,000 or more. When the knitted fabric density is 1,000 or more, the gaps between the plurality of constituent fibers are not excessively increased, and the heat shielding property is excellent.

  When the woven or knitted fabric of the present invention is a woven fabric, it preferably has a cover factor of 1100 to 2200. Moreover, when the woven or knitted fabric of the present invention is a knitted fabric, it preferably has a cover factor of 15 to 50. When the cover factor is within this range, good heat shielding properties can be expressed without becoming thick.

The cover factor (CF) is calculated by the following formula (II) in the case of a woven fabric, and is calculated by the following formula (III) in the case of a knitted fabric.
CF = WAD × √DT + WED × √DT (II)
CF = CD × √DT + WD × √DT (III)

Abbreviations in the above formula indicate the following.
DT: Fineness of multifilament yarn (dtex)
WAD: Warp density (main / 2.54cm)
WED: Weft density (main / 2.54cm)
CD: Course density (book / 2.54cm)
WD: Wale density (book / 2.54cm)

Woven or knitted fabric of the present invention preferably has a basis weight of 30~300g / m ^2. When the weight per unit area is in such a range, good heat shielding properties can be expressed without becoming thick.

  The infrared reflectance of the woven or knitted fabric of the present invention is preferably 60% or more, and more preferably 61% or more. As an upper limit of the infrared reflectance of the woven or knitted fabric of the present invention, for example, about 80% can be mentioned. The infrared reflectance can be appropriately set by adjusting the cross-sectional shape of the hollow multifilament yarn, the inorganic oxide particle concentration, false twisting conditions, and the like. The infrared reflectance is an index of heat shielding properties, and the higher this value, the better the heat shielding properties. The method for obtaining the infrared reflectance will be described later in Examples.

  The woven or knitted fabric of the present invention is excellent in heat shielding properties, and also has good bulkiness and texture. Therefore, it is particularly suitably used not only for general clothing, but also for office uniforms such as blouses, medical applications such as lab coats, and sportswear.

  Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

  In addition, the measuring method or evaluation method of each physical property is as follows.

<Hollow rate>
The cross section of each hollow fiber contained in the hollow multifilament yarn, and the cross section of each single fiber contained in the false twisted hollow multifilament yarn and false twisted multifilament yarn are respectively optical microscopes (trade name, manufactured by Olympus Corporation). A cross-sectional photograph was taken at a magnification of 580 times using “BH2-UMF”). From the obtained cross-sectional photographs, for each hollow fiber and each single fiber, the radius of each hollow fiber and each single fiber and the radius of the hollow part were measured, and the entire area and the area of the hollow part were calculated. And about each hollow fiber and each single fiber, the ratio of the area of the hollow part with respect to the whole area was computed, and the hollow rate was calculated | required. The measurement of the hollow ratio is performed for the hollow multifilament yarn (hollow yarn) before false twisting and the false twisted multifilament yarn (single fiber) after false twisting of Example 1 and Comparative Examples 1 and 2. Table 1 shows the ratio of single fibers having a hollow ratio of 0% (number%) and the ratio of single fibers having a hollow ratio of 3% or more (number%). In addition, in each cross-sectional photograph, the hollow ratio was set to 0% when the hollow portion could not be visually confirmed. Moreover, in the cross-sectional photograph of the false-twisted multifilament yarn after false twisting, the hollow ratio was calculated by the above method for the ones in which the hollow portion was confirmed, and the ratio of single fibers having a hollow ratio of 3% or more (number) %).

<Crimping rate>
The crimp rate was measured by the method described above.

<Heat insulation (infrared reflectance)>
Using a spectrophotometer “SIMAZU UV-3100PC” manufactured by Shimadzu Corporation, the average infrared reflectance at a wavelength of 700 to 1200 nm of the target sample was measured.

<Bulkyness (bulky)> (Sensory evaluation)
The woven fabrics obtained in Examples and Comparative Examples were evaluated according to the following criteria based on tactile sensation.
○: Bulkiness (bulky property) is good.
Δ: Bulkiness (bulky property) is normal.
X: Bulkiness (bulky property) is poor.

Ratio of the exposed length (μm) of the segment A on the single yarn surface to the outer peripheral length (μm) of the single yarn (EC)
The cross section of the single yarn taken out from the multifilament with respect to the longitudinal direction was observed with an optical microscope (PCSCOPE PCS-81X manufactured by INABATA & CO), and the single yarn outer peripheral length (μm) and the exposed length of the segment A on the single yarn surface (μm) Was measured and the ratio (EC (%)) to the single yarn outer peripheral length (μm) was calculated by the following equation.
EC = exposed length of segment A (μm) / peripheral length of single yarn (μm) × 100 (%)

Average ratio (DC) of the shortest distance (μm) from the outer periphery of the single yarn to the leaf (μm) to the distance (μm) from the center of the single yarn to the outer periphery of the single yarn
The cross section of the single yarn taken out from the multifilament yarn was observed with an optical microscope (PCSCOPE PCS-81X made by INABATA & CO), the distance from the center of the single yarn to the outer periphery of the single yarn (μm), and the single yarn in each leaf part. The shortest distance (μm) from the yarn outer periphery to each leaf was measured. And the average ratio (DC (%)) of the shortest distance (μm) from the single yarn outer periphery to each leaf portion in each leaf portion with respect to the distance (μm) from the center of the single yarn to the single yarn outer periphery was calculated by the following equation. .
DC = average value of the shortest distance from the outer periphery of the single yarn to each leaf (μm) / distance from the center of the single yarn to the outer periphery of the single yarn (μm) × 100 (%)

Example 1, Comparative Examples 1 and 2
(Manufacture of hollow multifilament yarn)
As the first resin, a polyester resin (PET, intrinsic viscosity: 0.65) was formed into a chip by a conventional method and dried. Titanium oxide fine particles (TiO ₂ ) were contained as inorganic oxide particles in a proportion of 5.0% by mass with respect to this PET. As the second resin, a polyester resin (PET, intrinsic viscosity: 0.65) was chipped by a conventional method and dried. Titanium oxide fine particles (TiO ₂ ) were added to this PET so as to have a ratio of 0.4 mass%. Using the first resin and the second resin PET containing titanium oxide fine particles, and using a spinneret for hollow, the mass ratio of the first resin part and the second resin part ( The first resin part / second resin part) is 75/25, and the spinning temperature is 295 ° C. so that the first resin part forms segment A and the second resin forms segment B. A multifilament is spun and taken up by a take-up roller at a speed of 3,000 m / min. As shown in FIG. 1C, the hollowness is 15%, the number of leaf parts is 20, and EC is 3%. A hollow multifilament yarn (160 dtex, 72 filaments) with DC of 2% (elongation: 37.2%, birefringence: 0.230) was obtained. When the hollow multifilament yarn was spun, there was no cut yarn, and the yarn-making property was good.

(Manufacture of false twisted multifilament yarn)
The false twist of Example 1 was applied to the hollow multifilament yarn obtained as described above under the false twisting conditions shown in Table 1 so that the hollow portion was compressed (collapsed). A multifilament yarn was obtained. On the other hand, the hollow multifilament yarn obtained as described above was subjected to false twisting under the false twisting conditions shown in Table 1 so as to suppress the compression (collapse) of the hollow portion of the hollow fiber. The false twist hollow multifilament yarns of Comparative Examples 1 and 2 were obtained. The crimp rate and hollow rate of the false twisted multifilament yarn of Example 1 and the false twisted hollow multifilament yarn of Comparative Examples 1 and 2 were subjected to evaluation.

Example 2
(Manufacture of hollow multifilament yarn)
As the first resin, a polyester resin (PET, intrinsic viscosity: 0.65) was formed into a chip by a conventional method and dried. Titanium oxide fine particles (TiO ₂ ) were contained as inorganic oxide particles in a proportion of 5.0% by mass with respect to this PET. As the second resin, a polyester resin (PET, intrinsic viscosity: 0.65) was chipped by a conventional method and dried. Titanium oxide fine particles (TiO ₂ ) were added to this PET so as to have a ratio of 0.4 mass%. Using the first resin and the second resin PET containing titanium oxide fine particles, and using a spinneret for hollow, the mass ratio of the first resin part and the second resin part ( The first resin part / second resin part) is 75/25, and the spinning temperature is 297 ° C. so that the first resin part forms segment A and the second resin forms segment B. A multifilament is spun and taken up by a take-up roller at a speed of 3,000 m / min. As shown in FIG. 1C, the hollowness is 15%, the number of leaf parts is 20, and EC is 3%. A hollow multifilament yarn (250 dtex, 72 filaments) with a DC of 2% (elongation: 145.8%, birefringence: 0.035) was obtained. When the hollow multifilament yarn was spun, there was no cut yarn, and the yarn-making property was good.

(Manufacture of false twisted multifilament yarn)
The false twist of Example 2 was applied to the hollow multifilament yarn obtained as described above under the false twisting conditions shown in Table 1 so that the hollow portion was compressed (collapsed). A multifilament yarn was obtained. In addition, a friction method is used for the false twisting method, and false twisting (D / Y): 1.70, yarn speed of 500 m / min, heater temperature of 330 ° C., and draw ratio of 1.60 times are used. went.

Comparative Example 3
(Manufacture of multifilament yarn having a leaf portion by segment A but not having a hollow portion)
Example 1 except that the spinneret attached to the nozzle is changed from a spinneret for hollow to a medium-practical spinneret (a base for obtaining a multifilament yarn having a round cross-section with no hollow cross section). As a result, a multi-filament yarn having a round cross section (168 dtex, 72 filaments) having no hollow part (the number of leaf parts was 20, EC was 3%, DC was 2%) was obtained.

(Manufacture of false twisted multifilament yarn)
This polyester filament yarn was false twisted under the conditions shown in Table 1 to obtain a false twist multifilament yarn of Comparative Example 3.

Comparative Example 4
(Manufacture of multifilament yarn having no hollow part in which titanium oxide fine particles are uniformly dispersed)
A polyester resin (PET, intrinsic viscosity: 1.38) was chipped by a conventional method and dried. Titanium oxide fine particles (TiO ₂ ) were contained as inorganic oxide particles at a ratio of 2.0 mass% with respect to this PET. Using this PET, a multifilament was spun at a spinning temperature of 295 ° C. and taken up by a take-up roller at a speed of 3,000 m / min, to obtain a multifilament yarn having a round cross section (160 dtex, 72 filaments) having no hollow portion. .

(Manufacture of false twisted multifilament yarn)
This multifilament yarn was false twisted under the conditions shown in Table 1 to obtain a false twist multifilament yarn of Comparative Example 4.

(Manufacture of woven and knitted fabrics)
Each of the false twisted multifilament yarns or false twisted hollow multifilament yarns obtained in Examples 1 and 2 and Comparative Examples 1 to 4 was placed on a weft, and a polyester multifilament yarn (manufactured by Unitika Ltd., 56 dtex / 48 filament). Were placed on the warp to obtain each woven or knitted fabric of Examples 1-2 and Comparative Examples 1-4 (flat structure, warp density: 150 / 2.54 cm, weft density: 70 / 2.54 cm). In each woven or knitted fabric, the mixed rate of false twisted multifilament yarn and false twisted multifilament yarn (that is, the mixed rate of weft yarn) was 58% by mass. Each woven or knitted fabric was subjected to scouring in accordance with a conventional method, and heat set finishing was performed under the conditions of 170 ° C. × 1 minute for evaluation of heat shielding properties (infrared reflectance).

  Evaluation results of false twisted multifilament yarns obtained in Examples 1 and 2 and Comparative Examples 3 and 4, false twisted hollow multifilament yarns obtained in Comparative Examples 1 and 2, and woven and knitted fabrics obtained using these Is shown in Table 1.

  As can be understood from Table 1, the false-twisted multifilament yarns of Examples 1 and 2 are excellent in heat-shielding properties when made into a woven or knitted fabric and have a high crimp rate, so that the woven or knitted fabric has a bulky and bulky texture. was gotten. FIG. 2 is a cross-sectional photograph of the false twisted multifilament yarn of Example 1 (580 times). From FIG. 2, it can be seen that the false-twisted multifilament yarn of Example 1 has a single fiber hollow portion crushed.

  Examples 1 and 2 showed excellent heat shielding properties as compared with Comparative Example 3. This is because, when light passes through the false twisted multifilament yarn and the woven or knitted fabric, the reflectance and the refraction at the portion where the hollow portion of the single fiber constituting the false twisted multifilament yarn is crushed (discontinuous portion). It can be understood that the phenomenon increases. In addition, the reason why Comparative Examples 1 and 2 showed excellent heat shielding properties compared with Comparative Example 3 is that the reflectivity and refraction phenomenon in the hollow portion of the single fiber constituting the false twisted multifilament yarn are It can be understood that it will grow.

  In Comparative Examples 1 and 2, false twisted hollow multifilament yarns were obtained by adjusting the false twisting conditions of hollow multifilament yarns made of hollow fibers so as to prevent the hollow portion from being crushed. Specifically, processing was performed at low heater temperature (° C.) and false twist number (T / M) under false twisting conditions. For this reason, in Comparative Examples 1 and 2, although collapse of the hollow portion is suppressed, only a false twisted hollow multifilament yarn with a low crimp rate can be obtained, and the texture when woven or knitted is also bulky. Only knitted and knitted fabrics were obtained. FIG. 3 is a cross-sectional photograph of the false twisted multifilament yarn of Comparative Example 1 (580 times). From FIG. 3, it can be seen that the false-twisted hollow multifilament yarn of Comparative Example 1 has a single fiber hollow portion remaining.

  In Comparative Example 3, false twisted multifilament yarn was obtained by false twisting a polyester filament made of a single yarn having no hollow part. Since Comparative Example 3 does not have a hollow portion or a portion where the hollow portion is crushed in the single fiber, light reflection and refraction phenomenon do not occur, and when compared with Examples 1 and 2 and Comparative Examples 1 and 2, the shielding is not performed. Only a woven or knitted fabric inferior in heat property was obtained.

  In Comparative Example 4, titanium oxide is uniformly dispersed in a single fiber, and a polyester filament having the same titanium oxide concentration as that in Examples 1 and 2 and Comparative Examples 1 to 3 is false twisted, and false twisted multifilament I got a thread. As a result of comparison with Examples 1 and 2, Comparative Example 4 does not have a portion where the hollow portion or the hollow portion is crushed in the single fiber, as in Comparative Example 3, so that light reflection and refraction phenomenon do not occur, When compared with Examples 1 and 2 and Comparative Examples 1 and 2, only a woven or knitted fabric having inferior heat shielding properties was obtained.

1 single fiber 2 segment A in which the content X (% by mass) of inorganic oxide particles is 2 <X ≦ 10
3 Segment B in which the content Y (mass%) of the inorganic oxide particles is 2 mass% or less
4 Leaf part 5 Hollow part

Claims (9)

A false twist multifilament yarn comprising a polyester resin containing inorganic oxide particles,
The false twisted multifilament yarn is a false twisted multifilament yarn in which the hollow portion of the hollow fiber is compressed and the proportion of single fibers having a hollowness of less than 3% is 95% or more.   The false twist multifilament yarn according to claim 1, wherein the crimp rate of the false twist multifilament yarn is 35% or more.   The false twist multifilament yarn according to claim 1 or 2, wherein the content of the inorganic oxide particles in the polyester resin is 10% by mass or less.   The false twist multifilament yarn according to any one of claims 1 to 3, wherein the single fiber has a fineness of 0.5 to 2.5 dtex. In the hollow fiber, the content X (mass%) of the inorganic oxide particles is 2 <X ≦ 10, and the content Y (mass%) of the inorganic oxide particles is 2 mass% or less. Segment B,
The false-twisted multifilament yarn according to any one of claims 1 to 4, wherein a shape of a cross section with respect to a longitudinal direction of the hollow fiber further satisfies the following (1) to (5).
(1) The shape of the segment A in the cross section is a multi-leaf shape including 6 to 30 leaf portions radially extending from the center side to the outer peripheral side of the hollow fiber.
(2) The distal end portion on the outer peripheral side of the leaf portion has a curved shape.
(3) The ratio of the exposed length (μm) of the segment A to the hollow fiber surface with respect to the outer peripheral length (μm) of the hollow fiber is 10% or less.
(4) The average ratio of the shortest distance (μm) from the outer periphery of the hollow fiber to the leaf part to the distance (μm) from the center of the hollow fiber to the outer periphery of the hollow fiber is 10% or less.
(5) The hollow ratio of the hollow fiber is 5 to 30%. Preparing a hollow multifilament yarn made of a polyester resin containing inorganic oxide particles;
A step of subjecting the hollow multifilament yarn to false twisting so that the proportion of single fibers having a hollowness of less than 3% is 95% or more;
A process for producing false twisted multifilament yarn. In the hollow multifilament yarn, the content X (mass%) of the inorganic oxide particles is 2 <X ≦ 10, and the content Y (mass%) of the inorganic oxide particles is 2 mass% or less. A hollow fiber having a segment B which is
The manufacturing method of false twist multifilament yarn in which the shape of the cross section with respect to the longitudinal direction of the hollow fiber further satisfies the following (1) to (5).
(1) The shape of the segment A in the cross section is a multi-leaf shape including 6 to 30 leaf portions radially extending from the center side to the outer peripheral side of the hollow fiber.
(2) The distal end portion on the outer peripheral side of the leaf portion has a curved shape.
(3) The ratio of the exposed length (μm) of the segment A to the hollow fiber surface with respect to the outer peripheral length (μm) of the hollow fiber is 10% or less.
(4) The average ratio of the shortest distance (μm) from the outer periphery of the hollow fiber to the leaf part to the distance (μm) from the center of the hollow fiber to the outer periphery of the hollow fiber is 10% or less.
(5) The hollow ratio of the hollow fiber is 5 to 30%.   A woven or knitted fabric comprising the false-twisted multifilament yarn according to any one of claims 1 to 5.   The woven or knitted fabric according to claim 8, wherein an average infrared reflectance at a wavelength of 700 to 1200 nm is 60% or more.