WO2016133196A1

WO2016133196A1 - Fiber bundle and false twisted yarn, woven knitted item, and clothing containing same

Info

Publication number: WO2016133196A1
Application number: PCT/JP2016/054849
Authority: WO
Inventors: 純哉今北; 横山　淳一; 哲也山岡
Original assignee: 三菱レイヨン・テキスタイル株式会社
Priority date: 2015-02-20
Filing date: 2016-02-19
Publication date: 2016-08-25
Also published as: JPWO2016133196A1; TW201641763A; TWI615519B

Abstract

Provided is a hollow polyester multifilament that has a polygonal cross-sectional shape; in which a single fiber has a rectangular to octagonal cross-sectional shape; that has a single hollow section; and in which single fibers having a right-hexagonal cross-sectional shape preferably account for 70 % or greater of the total number of fibers in the lateral cross-section of the multifilament. In addition to the see-through prevention due to refraction of light at the fiber surfaces, the thermal insulation performance is increased because it is possible to load the fibers at the greatest density, the fiber weight is reduced due to having the hollow section, and, in the case in which the hollow section has a circular shape, light is randomly refracted, thus, achieving a greater see-through prevention. Also, when used as a textured yarn in a woven knitted item, weight reduction, excellent thermal insulation, a light blocking effect, and see-through prevention are strongly exhibited.

Description

Fiber bundle and false twisted yarn, knitted fabric and garment containing the same

[Technical Field] The present invention relates to a fiber bundle suitable for a woven or knitted fabric that is excellent in heat shielding properties, light shielding properties, and see-through prevention even if it is a light color, and a false twisted yarn including the same, a woven or knitted fabric, and a garment.

Conventionally, the polyester fiber polygonal cross-section fibers have been used for woven and knitted clothing because the polyester fiber hollow fibers are excellent in lightness and sharpness. Polygonal cross-section hollow polyester fibers combined with each other have also been proposed, for example, in JP-A-4-257314 (Patent Document 1) and JP-A-9-157958 (Patent Document 2).

However, the polygonal cross-section hollow polyester fiber in which the polygonal cross-section fiber and the hollow fiber are simply combined morphologically becomes closer to the round cross section and the characteristics of the polygon cross-section fiber are not sufficiently exhibited as the polygon becomes higher.

Conventionally, fibers used for curtains and clothes intended to block radiant heat from sunlight, white pigments such as titanium oxide, talc and barium sulfate, and inorganic fine particles such as carbon black and aluminum powder are dispersed in the fiber. For example, JP-A-11-81048 (Patent Document 3) and JP-A-9-137345 (Patent Document 4) are known.

Furthermore, for example, according to Japanese Patent Application Laid-Open No. 2012-12726 (Patent Document 5), a method for increasing the heat shielding property of a woven or knitted fabric using fibers having a flat cross section is disclosed, and Japanese Patent Application Laid-Open No. 2014-177716 (Patent Document). According to Document 6), the cross-sectional shape is a leaf-like fiber, and the core component is composed of a thermoplastic polymer containing a fine solar light shielding material in an amount of 8 wt% to 70 wt%, and the sheath component is inorganic fine particles 0. 2. Description of the Related Art A core-sheath type irregular cross-section composite fiber composed of a polyester-based polymer containing 5% by weight or more and 10% by weight or less and a fiber assembly thereof are known.

As described above, although woven and knitted fabrics having many types of heat-shielding properties and anti-slipping properties (hereinafter sometimes referred to as “permeability”) are known, further heat-shielding properties and anti-permeable properties are known. There is a demand for a woven or knitted fabric excellent in properties.

JP-A-4-257314 Japanese Patent Laid-Open No. 9-157958 Japanese Patent Laid-Open No. 11-81048 JP-A-9-137345 JP 2012-12726 A JP 2014-177716 A

The present invention was created based on the discovery that a fiber having a hollow section and a polygonal cross-section fiber in a specific range exhibits new remarkable characteristics.

The object of the present invention is a process in which a hollow polyester multifilament having a square to octagonal cross section and a false polyester hollow filament multifilament are suitable for a woven or knitted fabric that is lightweight and excellent in heat shielding properties, light shielding properties, and see-through prevention properties. To provide yarn.

Another object of the present invention is to provide a woven or knitted fabric that is excellent in heat shielding and permeation resistance even if it is thin, and various garments using the woven or knitted fabric.

The main configuration of the present invention satisfies any of the following 1 to 16.
1. A fiber bundle having a heat shielding property of 40 ° C. or less and a lightness L ^* value of 50 or more when a basis weight is 140 to 150 g / m ² with a 1.16 G rib knitted fabric.
2. 2. The fiber bundle according to 1, wherein the knitted fabric has a visible light transmittance of 30% or less and the fiber bundle is made of polyester fiber.
3. In the single fiber of the fiber bundle, the fiber cross-sectional shape perpendicular to the fiber axis is a shape having 4 to 8 corners, has a single hollow part, and the cross-sectional shape perpendicular to the fiber axis of the hollow part The fiber bundle according to 1 or 2, wherein is a circular shape.
4). 4. The fiber bundle according to any one of 1 to 3 above, containing 1 to 3% by mass of titanium dioxide.
5. 5. The fiber bundle according to any one of 1 to 4, wherein the number of single fibers in the fiber bundle is 6 to 72.
6). 6. The fiber bundle according to any one of 1 to 5, wherein the hollow ratio of the hollow portion is 10 to 40%.
7). 7. The fiber bundle according to any one of 1 to 6, wherein the single fiber fineness is 1 to 8 dtex, and the total fineness is 6 to 575 dtex.
8). 8. The fiber bundle according to any one of 1 to 7 above, wherein the single fiber strength is 2 to 5 cN / dtex.
9. A false twisted yarn having a false twist coefficient of 8000 to 30000 comprising the fiber bundle according to any one of 1 to 8 above.
10. A woven or knitted fabric having a basis weight of 50 to 180 g / m ² , a permeability of 95% or more, and a lightness L ^* value of 50 or more.
11. 11. The woven or knitted fabric according to 10 above, wherein the fabric thickness is 0.2 to 0.5 mm.
12 The woven or knitted fabric according to 10 or 11 above, wherein the transmittance of visible light having a wavelength of 400 to 780 nm is 24.5% or less.
13 13. The woven or knitted fabric according to any one of 10 to 12, wherein the heat shielding property is 41.0 ° C. or less.
14 14. The woven or knitted fabric according to any one of 10 to 13, wherein the fiber bundle according to any one of 1 to 8 is contained in an amount of 30 to 100% by mass.
15. A garment containing 70% or more of the woven or knitted fabric according to any one of 10 to 14 above.
16. 16. The garment according to 15, wherein the garment includes a uniform and sportswear.

The hollow polyester multifilament having a square to octagonal cross section according to the present invention has a fiber cross-sectional shape in a single range, so that the fiber cross-sectional shape has an effect of preventing see-through due to light refraction on the fiber surface and the fiber cross-sectional shape is By including 70% or more of the polygonal single yarn as described above, the closest packing can be achieved. Therefore, the heat shielding property is improved and the hollow portion has not only a lightweight fiber but also a fiber. If the shape of the hollow part of the cross section is circular, the light refraction is random, more effective in preventing see-through, and even when false twisting is performed, the hollow part is not easily crushed. It is a fiber that can exhibit excellent heat shielding properties, light shielding properties, and see-through prevention properties.

The woven or knitted fabric of the present invention has excellent heat shielding properties and permeation preventing properties even if the woven or knitted fabric is thin.

It is a photograph (400 times) of the cross section of the direction perpendicular | vertical with respect to the fiber axial direction of an example of the fiber bundle of this invention. It is a fiber sectional view used for optical simulation of a hexagonal section hollow circle section which is an example of the present invention. It is a diagram which shows the result of the optical simulation of a hexagonal cross-section hollow round cross section which is an example of this invention. It is a fiber sectional view used for optical simulation of a hexagonal section hollow hexagonal section which is an example of the present invention. It is a diagram which shows the result of the optical simulation of a hexagonal section hollow hexagonal section which is an example of the present invention.

Hereinafter, embodiments of the present invention will be described in detail.
The fiber bundle of the present invention has a heat shielding property of a knitted fabric of 40 G or less and a lightness L ^* value of 50 or more when the basis weight is 140 to 150 g / m ² with a 16 G rib knitted fabric.
Using the fiber bundle of the present invention, a knitted fabric having a rib structure is knitted with a 16 G knitting machine having 16 knitting needles per inch, and the basis weight is 140 to 150 g / m ² .
The type of the knitting machine is not particularly limited as long as the rib knitted fabric can be knitted. For example, a flat knitting machine or a circular knitting machine can be used.
The basis weight is adjusted by adjusting the degree of stitch filling.

The heat shielding property is measured by a measurement method described later.
In addition, the heat shielding property decreases as the color of the woven or knitted fabric becomes lighter. However, in the present invention, even if the lightness L ^* value of the woven or knitted fabric is lighter than a medium color of 50 or more, the effect of the heat shielding property is reduced. Is expensive.
Therefore, the fiber bundle of the present invention has a lightness L ^* value of 60 or more and is more likely to have a heat-shielding effect, and a lightness L ^* value of 70 or more tends to have a further effect.
The lightness L ^* value is expressed in a numerical range of 0 to 100, where 0 is a dark black color and 100 is a light white color.
Regarding the heat shielding property of the woven or knitted fabric, it is considered that the thinner the color, the easier it is to transmit infrared rays, so the heat shielding property is lowered.

The fiber bundle of the present invention preferably has a visible light transmittance of 30% or less of the knitted fabric, and the fiber bundle is made of polyester fibers.
As for the visible light transmittance, the thinner the knitted fabric, the higher the transmittance, and the lighter the knitted fabric, the higher the transmittance. However, when the fiber bundle of the present invention is made into a knitted fabric, the visible light transmittance is easily lowered even if the knitted fabric is thin and the color of the knitted fabric is light.
When the visible light transmittance is low, the underwear is less likely to show through when it is worn.
From this viewpoint, the visible light transmittance is more preferably 27% or less, and further preferably 24% or less.

The fiber bundle of the present invention is not particularly limited as long as it is a chemical fiber. Examples thereof include polyethylene terephthalate fiber, polyamide fiber, polyolefin fiber, and acrylic fiber. Among them, polyethylene terephthalate fiber is more preferable because it has a refreshing feeling and produces a modified cross-section hollow fiber. Examples of the polymer constituting the polyester multifilament include a polyester having ethylene terephthalate as a main constituent unit, and the polyester may contain a copolymer component. Copolymerization component includes isophthalic acid component, sulfonic acid metal group-containing isophthalic acid component, aromatic dicarboxylic acid component other than terephthalic acid component such as adipic acid component, aliphatic dicarboxylic acid component other than ethylene glycol component Component.

The fiber bundle of the present invention is a single fiber, the cross-sectional shape of the fiber perpendicular to the fiber axis is a polygonal shape having 4 to 8 corners, has a single hollow part, and is perpendicular to the fiber axis of the hollow part The cross-sectional shape in the direction is preferably circular.
In addition, the fiber cross section in the present invention means a fiber cross section perpendicular to the fiber axis. When the fiber cross-sectional shape of the single fiber has 4 to 8 corners, the single fibers are easily arranged without gaps in the fiber bundle state, and the close-packing property is improved.

From the above viewpoint, it is more preferable that the fiber cross-sectional shape of the fiber bundle of the present invention has six corners. When the fiber cross-sectional shape has six corners, it becomes a hexagon and close-packing is possible. The hexagon may have rounded corners, but the radius of curvature of the round is less than the radius of the inscribed circle of the hexagon. And as long as all sides do not consist of straight lines, it is only necessary to form a hexagon that can be closely packed, and the multifilament has a fiber cross-sectional shape with some sides curved or some corners It may contain rounded hexagonal single yarn.

In addition, the hexagon in the present invention includes those that cannot be said to be geometrical hexagons. Among the hexagons, in particular, the corners at which the straight portions of any side and the adjacent sides intersect each other. A hexagon that is the same as or similar to a hexagon having an interior angle of 120 degrees and an equal length between adjacent corners. At this time, there may be an error in the angle of the inner angle and the length of adjacent sides.

Moreover, the single fiber which comprises the fiber bundle of this invention has a single hollow part in the fiber cross section, and can make a hollow ratio high by making it a single hollow part. In the present invention, the hollow ratio of the hollow portion of the single fiber is preferably 10 to 40%. By having a hollow portion, an air layer is formed, the refractive index is increased, and the fiber cross-sectional shape of the hollow portion of the single fiber is preferably a circular shape in which light refraction is random.

As shown in FIG. 2 and FIG. 4, when the fiber cross-sectional shape of the single fiber is a hexagon and the hollow part is a round cross section and a hexagon cross section, when compared with the intensity of light in the normal direction by optical simulation, The intensity of the hollow section having a round cross section is 20 (see FIG. 3), the intensity of the hollow section having a hexagonal cross section is 110 (see FIG. 5), and the intensity of light transmitted through the hollow section having a round cross section. Is small and difficult to see through.

The optical simulation was performed by the following method.
The analysis software was performed using LightTools ver8.2 (Synopsys, Inc.).
The following conditions were set as conditions.
-Hollow fibers were modeled in three dimensions.
-The refractive index of the material was 1.6 assuming polyester fibers.
-Fresnel loss was set on the fiber surface.
-The light source emits light only in the range of 0 ° to 5 ° in the normal direction.
-The light receiving part was set on the opposite side of the light source, and the angular distribution of the light that reached the light receiving part hitting the fiber at least once was obtained.
In consideration of the random orientation of the fiber, a total of 12 patterns obtained by rotating the fiber by 60 ° every 5 ° was obtained.

The fiber bundle of the present invention includes 50% or more of single fibers having a regular hexagonal fiber cross-sectional shape in the cross section of a multifilament composed of single yarns having a hexagonal fiber cross-sectional shape with respect to the total number of single fibers. The close-packing property is further enhanced by the large number of regular hexagonal single fibers. From the above viewpoint, it is preferable that 70% or more of single fibers having a regular hexagonal fiber cross-sectional shape are included with respect to the total number of single fibers, and more preferably 80% or more.
In addition, the cross section of a single fiber means the cross section of the direction perpendicular | vertical with respect to the fiber axis direction of a single fiber.

The fiber bundle of the present invention preferably contains 1 to 3% by mass of titanium dioxide.
By containing 1% by mass or more of titanium dioxide, the see-through preventing effect tends to be good, and if it is 3% by mass or less, the yarn-making property tends to be good.
From the above viewpoint, the content of titanium dioxide is more preferably 1.5 to 2.5% by mass.

The fiber bundle of the present invention is preferably a fiber bundle having 6 to 72 single fibers. If the number of single fibers is 6 or more, it is preferable that the effect of preventing see-through is obtained by being closely packed, and if it is 72 or less, the thickness of the entire fiber bundle does not become too thick for clothing use. From the above viewpoint, the number of single fibers in the fiber bundle is more preferably 12 to 48, and further preferably 16 to 40.

If the hollow ratio is 10% or more, light refraction is large and the effect of preventing see-through is increased. Moreover, if the said hollow rate is 40% or less, a hollow part will become difficult to be crushed when false twisting is carried out. From the above viewpoint, the hollowness is more preferably 15 to 30%, and further preferably 20 to 27%.

The fiber bundle of the present invention preferably has a single fiber fineness of 1.0 to 8.0 dtex. If the single fiber fineness is 1.0 dtex or more, the yarn production stability is good, and it is preferable because the yarn breakage is reduced during the production of the woven or knitted fabric, and the productivity tends to be good, and if it is 8.0 dtex or less, it is used for clothing. The texture of the fiber is not too hard and the number of single fibers can be increased, so that a large amount of light can be refracted, and the effect of permeation and heat insulation can be easily obtained. This is preferable because a texture can be easily obtained. From the above viewpoint, the single fiber fineness is more preferably 2.0 to 6.0 dtex.

The fiber bundle of the present invention preferably has a total fineness of 6 to 575 dtex. If the total fineness is 6 dtex or more, it is preferable because the close-packing can be performed and the heat shielding effect is enhanced, and if it is 575 dtex or less, the texture in clothing use is not too hard. From the above viewpoint, the total fineness is more preferably 32 to 240 dtex, and further preferably 50 to 120 dtex.

The fiber bundle of the present invention preferably has a single fiber strength of 2.0 to 5.0 cN / dtex. If the single fiber strength is 2.0 cN / dtex or more, the fiber bundle is difficult to cut during weaving or knitting of the knitted or knitted fabric, which is preferable. An upper limit of fiber strength of about 5.0 cN / dtex is sufficient.

The fiber bundle of the present invention is preferably a long fiber because of its characteristics, but may be a short fiber, a web, or a spun yarn made of a short fiber.

The fiber bundle of the present invention is produced, for example, by melt spinning using polyethylene terephthalate having an intrinsic viscosity of 0.676 as a raw material, preferably adding a matting agent such as titanium dioxide. If titanium dioxide is used, the matte effect is enhanced and the effect of preventing see-through is exhibited. Therefore, it is preferable to add 1.0 to 3.0% by mass of titanium dioxide.

As the spinneret for melt spinning, a spinneret having a plurality of nozzle holes each having six inner slits having an inner angle of 120 degrees arranged in an annular shape is preferably used. According to the spinneret having such nozzle holes, a hexagonal cross-sectional shape equivalent to a regular hexagon in which the inner angle of each vertex is 120 degrees and the length of each side between the vertexes is equal is obtained.

The melt spinning can be produced by employing a general melt spinning process and a drawing process in the same manner as melt spinning of solid fibers having a normal round cross section of polyethylene terephthalate. First, in the melt spinning step, a raw thermoplastic resin is melt extruded from a spinneret to obtain an undrawn yarn, and after winding it, a fiber is obtained by drawing in the drawing step. In the stretching step, the unstretched yarn may be spun and continuously stretched in-line, or may be stretched independently on another line after being wound up. Further, the stretching process may be one stage or may be a multistage having two or more stages. Further, the heat source used in the stretching step may be either a contact type or a non-contact type heat source. The draw ratio can be arbitrarily set within a range before reaching the breaking elongation of the melt-spun undrawn yarn.

For example, the yarn is discharged from a spinneret at a spinning temperature of 270 to 300 ° C., taken at a spinning (take-up) speed of 1000 to 2000 m / min to obtain an undrawn yarn, a drawing speed of 200 to 800 m / min, and a draw ratio of 0. The film is stretched under the conditions of 65 to 0.80 times, a stretching temperature of 60 to 90 ° C., and a heat setting temperature of 100 to 170 ° C. to obtain the hexagonal cross-section hollow polyester multifilament of the present invention as a stretched yarn. The maximum draw ratio refers to the ratio when the undrawn yarn is drawn at a drawing temperature of 80 ° C., a heat setting temperature of 145 ° C., and a drawing speed of 600 m / min until it is cut.

In the spinning process, the spun unstretched yarn is temporarily wound and then stretched, the spun unstretched yarn is stretched without being wound, and the spinning speed is 2000 m / min or more to form a semi-unstretched yarn. A method such as winding or stretching at high speed spinning without winding is used.

The false twisted yarn of the present invention is a false twisted yarn in which the fiber bundle of the present invention is false twisted and has a false twist coefficient of 8000 to 30000. In the fiber bundle of the present invention, when the cross section of a single fiber has 4 to 8 corners and a round hollow portion, the hollow portion is not easily crushed even when an external force such as false twisting is applied. If the false twisting coefficient is 8000 or more, it is preferable because a feeling of swelling as a crimped yarn can be obtained, and if it is 30000 or less, the hollow portion is not easily crushed. From the above viewpoint, the false twisting coefficient is more preferably 10,000 to 25,000.

Hereinafter, the form of the woven or knitted fabric of the present invention will be described in detail.
The woven or knitted fabric of the present invention has a basis weight of 50 to 180 g / m ² , a permeation resistance of 95% or more, and a lightness L ^* value of 50 or more.
If the weight per unit area is 50 g / m ² or more, the permeation-proof effect is easily obtained. If the basis weight is 180 g / m ² or less, a soft texture is easily obtained.
From the above viewpoint, the basis weight is more preferably 70 to 160 g / m ² or less, and further preferably 90 to 130 g / m ² or less.

The woven or knitted fabric of the present invention has a permeability of 95% or more. If the permeation resistance is 95% or more, it is a level at which the underwear or the like is transparent. From the viewpoint of permeability, the permeability is more preferably 95.2% or more.

The woven or knitted fabric of the present invention has a lightness L ^* value of 50 or more.
The lightness L ^* value is an index indicating the color intensity, and is indicated in the range of 0 to 100. 0 is black and dark, and 100 is white and light.
The permeation resistance varies depending on the color, and the effect decreases as the color of the woven or knitted fabric becomes lighter. In the present invention, however, the lightness L ^* value of the woven or knitted fabric is a lighter color than the medium color. Also, the effect of permeation prevention is high.
Therefore, the fiber bundle of the present invention has a lightness L ^* value of 60 or more and is more likely to have an anti-permeability effect, and has a lightness L ^* value of 70 or more and is more effective.

The fabric thickness of the woven or knitted fabric of the present invention is 0.2 mm or more and 0.5 mm or less. If the cloth thickness is 0.2 mm or more, it is difficult to tear during the production or use of clothes, and heat shielding properties and permeation resistance are likely to be good. If the cloth thickness is 0.5 mm or less, a desired thin woven or knitted fabric can be obtained. can get.
From the above viewpoint, the lower limit value of the cloth thickness is preferably 0.25 mm or more, more preferably 0.27 mm or more, and the upper limit value of the cloth thickness is preferably 0.45 mm or less, more preferably 0.40 mm.

The woven or knitted fabric of the present invention preferably has a visible light transmittance of 24.5% or less at a wavelength of 400 to 780 nm.
If the transmittance is 24.5% or less, the underwear or the like is at a level that does not matter.
From the above viewpoint, the transmittance is more preferably 24.0% or less, and further preferably 23.5% or less.

The woven or knitted fabric of the present invention preferably has a heat shielding property of 41.0 ° C. or lower. If the heat shielding property is 41.0 ° C. or lower, radiant heat can be suppressed even when it is exposed to sunlight, and the temperature rise in the clothes can be slowed, so that the comfortable time can be extended. From the above viewpoint, the heat shielding property is more preferably 40.8 ° C. or less.
The woven or knitted fabric of the present invention preferably contains 30% by mass or more and 100% by mass or less of the fiber bundle.
When the content of the multifilament with respect to the woven or knitted fabric is 30% by mass or more, the permeability and heat shielding properties are likely to be favorable, and 50% by mass or more is more preferable, and 80% by mass or more and 100% by mass or less. Is more preferable.

The fiber cross-sectional shape perpendicular to the fiber axis of the single fiber to be used is a shape having 4 to 8 corners. By having a single hollow portion, light passing through the woven or knitted fabric is likely to be irregularly reflected, thereby preventing permeation. And heat shielding properties are likely to improve.
The shape of the single fiber cross section is preferably a hexagon, more preferably a regular hexagon, but it may not be a regular hexagon.

In the woven or knitted fabric of the present invention, the cross-sectional shape perpendicular to the fiber axis of the hollow part is preferably a round cross section.
When the cross-sectional shape in the direction perpendicular to the fiber axis in the hollow portion is a round cross-section, the light is likely to be diffusely reflected, and the permeation resistance and the heat shielding property are likely to be better.
Here, the round cross section is preferably a perfect circle, but may be an ellipse and preferably has a curved portion of 50% or more.

The structure of the woven or knitted fabric of the present invention is not particularly limited. Since the fabric is preferably thin and clogged, a plain weave is more preferable. In the knitted fabric, a tengu structure and a smooth structure are preferable.
The garment of the present invention contains 70% by mass or more of the woven or knitted fabric. When the woven or knitted fabric is contained in an amount of 70% by mass or more, it becomes easy to obtain a garment having good permeability and heat shielding properties.
From the above viewpoint, the woven or knitted fabric is preferably contained in an amount of 85% by mass or more, more preferably 95% by mass or more, and most preferably 100% by mass.

The garment of the present invention preferably includes a uniform and sportswear.
Uniforms are more demanded of permeation resistance, and in particular, uniforms used in hospitals have many light colors and thin fabrics. Therefore, the fiber bundles and knitted fabrics of the present invention are preferably used.
In addition, sportswear is thin and the fabric is easy to see through when the fabric gets wet with sweat, and is often used outdoors. Bundles and knitted fabrics are preferably used.

Hereinafter, the present invention will be described more specifically based on examples.
In addition, each characteristic value in an Example was measured with the following method.
(Judgment of regular hexagon)
A cross section of a single fiber of a sample fiber bundle (in this specification, sometimes referred to as “multifilament”) is photographed using an optical microscope (400 ×), and the hexagonal corner (vertex) of the fiber cross section is taken. Is determined by measuring the angle of the inner angle and the length between adjacent vertices.

[Hollow rate (%)]
A cross-section of the single fiber of the sample fiber bundle is photographed using an optical microscope (400 times), and the ratio of the area of the hollow part to the fiber cross-sectional area including the hollow part is calculated to obtain the hollow ratio (%).

[Concentration of single fiber with regular hexagonal fiber cross section (%)]
A cross section perpendicular to the length direction of the fiber bundle of the sample is photographed using an optical microscope (400 times), the total number of single fibers and the number of single fibers of the regular hexagonal cross section are measured, and regular hexagons occupying the total number of single fibers The ratio of the number of single fibers in the cross section is calculated as the content (%) of single fibers having a regular hexagonal cross section. The measurement is performed at any three cross-sectional locations, and the average value is calculated.

[Thread spots (U%)]
The measurement was performed at a measurement speed of 15 m / min using a yarn spot tester (Ibnesester-KET-80C manufactured by Keiki Kogyo Co., Ltd.). The number of measurements is 3 and the average value is calculated.

[Water absorption]
Conforms to the following water absorption test method of the Boken Quality Evaluation Organization.
Dropping method: One drop of water is dropped from a height of 10 cm on the test piece attached to the holding frame, and the time (seconds) until the water drop disappears from the test piece is measured.
Bayrec method: A test piece measuring 200 mm × 25 mm in width is fixed at the upper end, dipped in the water with the lower end hanging down, allowed to stand for 10 minutes, and then the height (mm) at which the water has lifted the test piece is measured.

[Heat retention (%)]
Conforms to the following thermal insulation test method of the Bokken Quality Evaluation Organization.
Using a KES-F Thermolab II tester manufactured by Kato Tech, set the test piece on a hot plate set at a constant temperature (environmental temperature + 10 ° C), and calculate the amount of heat (a) dissipated through the test piece. Further, the amount of heat (b) dissipated without setting the test piece is obtained, and the heat retention rate (%) is calculated according to the following formula.
Thermal insulation rate (%) = (1−a / b) × 100

[Light transmittance (%)]
Using a UV-visible spectrophotometer (manufactured by JASCO Corporation, V-670), the light transmittance (%) is measured in each of the wavelength regions listed below. The transmittance is obtained by the following equation from the sum of the transmittance for each wavelength of 5 nm of the test piece (integrated amount Ts) and the sum of the background transmittance for each wavelength of 5 nm when there is no test piece (integrated amount Tg).
Transmittance (%) = (Ts / Tg) × 100
Ultraviolet light; measurement wavelength range 250 to 400 nm
Visible light; Measurement wavelength range: 400 to 700 nm
Infrared light: Measurement wavelength range 700-2000nm

[Heat insulation (℃)]
Conforms to the following Leflamp method of Kaken Test Center.
A 30 cm × 30 cm woven / knitted fabric sample was allowed to stand for 24 hours in a test room in which the atmospheric temperature was controlled to 20 ° C. and the humidity was controlled to 65%. The woven or knitted fabric sample is held 5 mm above the heat ray photoreceptor (black paper), irradiated with the lamp light of the reflex lamp from a distance of 50 cm on the sample side, and the temperature at the center of the heat ray photoreceptor on the opposite side of the sample. Was measured with a thermocouple over time for 15 minutes, and the temperature after 15 minutes was defined as the heat shielding temperature.
The test was measured 6 times under the following conditions:
Lamp used: Iwasaki Electric Co., Ltd. Eye lamp <Spot> PRS100V500W, Test chamber temperature: 20 ° C. ± 2 ° C.
Laboratory humidity: 65%
Each value obtained by averaging the data was used as a test result.

[Permeability (%)]
A 30 cm × 30 cm fabric sample was allowed to stand for 24 hours in a test room in which the ambient temperature was controlled to 20 ° C. and the humidity to 65%. The fabric sample was placed on top of a white tile and the brightness was measured using a spectrophotometer. Further, the sample was placed on the black tile, and the brightness was measured using a spectrophotometer.
Permeability (%) = (Lightness when using black tile (L ^* value) / Lightness when using white tile (L ^* value)) x 100
Test equipment: HunterLab spectrophotometer UltraScanPRO,
Measurement conditions: 10 ° visual field, light source D65, and regular reflection light were removed.

[Visible light transmittance (%)]
A 30 cm × 30 cm fabric sample was allowed to stand for 24 hours in a test room in which the ambient temperature was controlled to 20 ° C. and the humidity to 65%. The fabric samples were measured by performing the following operations (1) to (5) in order using a spectrophotometer (U-3400 manufactured by Hitachi, Ltd.).
(1) Prepare a woven or knitted fabric to be measured.
(2) The transmittance (%) without a sample (hereinafter referred to as Tg) was measured every 5 nm in the light wavelength range of 250 to 2000 nm.
(3) The sample was attached to the spectrophotometer, and the transmittance (%) with the sample (hereinafter referred to as Ts) was measured every 5 nm in the light wavelength range of 250 to 2000 nm.
(4) Ts was corrected using the following formula every 5 nm in the range of 250 to 2000 nm, and the corrected transmittance (hereinafter referred to as T) was calculated.
T = (Ts / Tg) × 100
(5) The arithmetic average value of T in the visible light region of 400 to 780 nm was calculated and used as the visible light transmittance.

[Brightness (L ^* value)]
Using a colorimeter (CM-7000d manufactured by Konica Minolta) for a 10 cm × 10 cm fabric sample, the index is 8 ° gloss, the field of view is 2 °, the mode is SCE (regular reflection light removal), the light source is D65 light, Two light sources were C light, and the L ^* value was measured with black paper sandwiched under the fabric sample.
Three locations on the fabric sample were measured 5 times, and the average value was taken as the result of the L ^* value.

(Example 1)
Using a polyethylene terephthalate with an intrinsic viscosity of 0.676 to which 2% by mass of titanium dioxide was added, a set of nozzle holes with a diameter of 1.0 mm in which six middle-folded slits having an inner angle of 120 degrees were arranged in an annular shape, Using a spinneret having 36 sets of nozzle holes, spinning was performed at a spinning temperature of 280 ° C., and the unwound yarn was wound at a take-up speed of 1400 m / min, and further drawn to a maximum draw ratio of 0.69 times to obtain a full dull of 84 dtex / A polyester multifilament with 36 filaments (f) (single yarn fineness 2.3 dtex) was prepared. As shown in FIG. 1, the obtained polyester multifilament is a single filament having a regular hexagonal cross section in the fiber cross section of the multifilament and a single hollow portion in the fiber cross section having a circular shape with a hollowness of 17.5%. The fibers were multifilaments accounting for 89% of the total number of single fibers.
The fiber properties of the obtained polyester multifilament were strength 3.70 cN / dtex, elongation 41.3%, BWS 8.1%, U% 0.48.
Moreover, the obtained polyester multifilament was false twisted with a false twist coefficient of 14,000. When the processed yarn subjected to false twisting was observed for the fiber cross section of the single yarn, the hollow portion was not crushed.

Using the obtained polyester multifilament, a rib knitted fabric was knitted with a 16G flat knitting machine. The evaluation results of the obtained knitted fabric are shown in Table 1. The obtained knitted fabric has the color of the raw yarn not dyed.
Since the visible light transmittance is lower than that of the control example, it can be seen that the anti-permeability is high. Despite being light-colored, it had higher heat-shielding properties and permeation-proof properties than the control example.

(Example 2)
In Example 1, the same procedure as in Example 1 was performed except that a set of nozzle holes with a diameter of φ1.0 mm in which six half-turn slits with an inner angle of 120 degrees were arranged annularly was replaced with a spinneret having 18 nozzles. Thus, a multifilament of 84 dtex / 18f (single yarn fineness 4.7 dtex) was prepared. In the obtained polyester multifilament, the cross section of the multifilament has a regular hexagonal cross section, and the single hollow portion in the cross section of the fiber has a circular shape with a hollowness of 25.3%. Multifilaments accounting for 94% of the total. The fiber properties of the obtained polyester multifilament were strength 4.00 cN / dtex, elongation 32.9%, BWS 7.4%, U% 0.42.
Moreover, the obtained polyester multifilament was false twisted with a false twist coefficient of 14,000. When the processed yarn subjected to false twisting was observed for the fiber cross section of the single yarn, the hollow portion was not crushed.
Using the obtained polyester multifilament, a rib knitted fabric was knitted with a 16G flat knitting machine. The evaluation results of the obtained knitted fabric are shown in Table 1. The obtained knitted fabric has the color of the raw yarn not dyed.
Since the visible light transmittance is lower than that of the control example, it can be seen that the anti-permeability is high. Despite being light-colored, it had higher heat-shielding properties and permeation-proof properties than the control example.

(Control example)
A single fiber made of a spinneret made of polyethylene terephthalate similar to that used in Example 1 and having 36 circular nozzle holes with a diameter of 0.25 mm has a round cross section and no round part. A knitted fabric obtained by knitting in the same manner as in Example 1 using a polyester multifilament of semi-dull 84 dtex / 36 f (single yarn fineness 2.3 dtex), which is a solid fiber of the same cross section as in the knitted fabric in Example 1. Table 1 shows the evaluation results of the evaluated control knitted fabric. The fiber physical properties of the polyester multifilament used were strength 4.25 cN / dtex, elongation 36.1%, BWS 8.1%, U% 0.43.

(Example 3)
A plain woven fabric was produced using the polyester multifilament obtained in Example 1 for warp and weft. Thereafter, dyeing was performed with a fluorescent disperse dye.
Table 2 shows the evaluation results of the fabric weight, fabric thickness, heat shielding property, light shielding property, visible light transmittance, and brightness of the obtained woven fabric.
The fabric is dyed with a fluorescent disperse dye, so it has excellent heat insulation and permeation resistance, and has a visible light transmittance despite its very light brightness, which is close to the color of raw silk that is not colored. It was low.

(Comparative Example 1)
A woven fabric was obtained in the same manner as in Example 1 except that the filament used was a filament in which an atypical cross section and a round cross section were mixed (manufactured by Toray Industries, Inc., “SEO α” (Part No. H67L) FD84T48F).
The evaluation results are shown in Table 2.

(Comparative Example 2)
The filament used was the same as in Example 1 except that the cross-sectional shape of the single fiber was a filament with a flat cross section having a constricted portion at two or more locations (manufactured by Teijin Fibers Ltd., “Wavelon” (Part No. F0212) FD84T30F). A woven fabric was obtained.
The evaluation results are shown in Table 2.

(Comparative Example 3)
The filament used was the same as in Example 1 except that the cross-sectional shape of the single fiber was a round cross-section and a filament containing 0% titanium oxide (manufactured by Nanya Co., Ltd., full dull yarn FD84T30F). It was.
The evaluation results are shown in Table 2.

The fiber bundle of the present invention, the processed yarn using the fiber bundle, and the woven or knitted fabric are materials that are excellent in heat shielding, permeation prevention, and see-through prevention in addition to being lightweight. It is suitable as a material for knitting and knitting for use in white clothing such as king clothing and nurse white clothing.

Claims

A fiber bundle having a heat resistance of 40 ° C. or less and a lightness L * value of 50 or more when a basis weight is 140 to 150 g / m 2 with a 16 G rib knitted fabric.
The fiber bundle according to claim 1, wherein the visible light transmittance of the knitted fabric is 30% or less, and the fiber bundle is made of a polyester fiber.
In the single fiber of the fiber bundle, the fiber cross-sectional shape perpendicular to the fiber axis is a shape having 4 to 8 corners, has a single hollow part, and the cross-sectional shape perpendicular to the fiber axis of the hollow part The fiber bundle according to claim 1 or 2, wherein is a circular shape.
The fiber bundle according to any one of claims 1 to 3, comprising 1 to 3% by mass of titanium dioxide.
The fiber bundle according to any one of claims 1 to 4, wherein the number of single fibers in the fiber bundle is 6 to 72.
The fiber bundle according to any one of claims 1 to 5, wherein a hollow ratio of the hollow portion is 10 to 40%.
The fiber bundle according to any one of claims 1 to 6, wherein the single fiber fineness is 1 to 8 dtex, and the total fineness is 6 to 575 dtex.
The fiber bundle according to any one of claims 1 to 7, wherein the single fiber strength is 2 to 5 cN / dtex.
A false twisted yarn having a false twist coefficient of 8000 to 30000 including the fiber bundle according to any one of claims 1 to 8.
A woven or knitted fabric having a basis weight of 50 to 180 g / m 2 , a permeation resistance of 95% or more, and a lightness L * value of 50 or more.
The woven or knitted fabric according to claim 10, wherein the fabric thickness is 0.2 to 0.5 mm.
The woven or knitted fabric according to claim 10 or 11, wherein the visible light transmittance at a wavelength of 400 to 780 nm is 24.5% or less.
The woven or knitted fabric according to any one of claims 10 to 12, which has a heat shielding property of 41.0 ° C or lower.
The woven or knitted fabric according to any one of claims 10 to 13, wherein the fiber bundle according to any one of claims 1 to 8 contains 30 to 100% by mass.
A garment containing 70% or more of the woven or knitted fabric according to any one of claims 10 to 14.
The garment according to claim 15, wherein the garment is a uniform or sportswear.