JP2013060677A - Black spun-dyed polyester fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a black spun-dyed polyester fiber that is superior in blackness, reduces heat absorption properties and can be suitably used for clothing and various industrial products, by using an infrared transmission type black dye or pigment.SOLUTION: The black spun-dyed polyester fiber contains 0.2-10 wt.% of the infrared transmission type black dye or pigment and satisfies conditions (1)-(3): (1) average reflectance in the black spun-dyed polyester fiber with 250-600 nm is 10% or less, and an average of transmissivity is 30% or more and an average of absorptance is 50% or less in the black spun-dyed polyester fiber with 1,000-2,000 nm; (2) strength of the black spun-dyed polyester fiber is 3.0 cN/dtex or more; and (3) single fiber fineness of the black spun-dyed polyester fiber is 0.5-5.0 dtex.

Description

  The present invention relates to a black original polyester fiber using an infrared transmitting black dye / pigment. More specifically, the present invention relates to a black primary polyester fiber which is excellent in blackness and excellent in heat absorption reduction and can be suitably used for clothing and various industrial products.

Polyester fiber is a fiber having high strength, high Young's modulus, and excellent thermal dimensional stability, and is widely used for clothing and industrial materials.
Among them, the black original polyester fiber is used in various applications as a polyester fiber having a deep black color, which is difficult by normal dyeing.
However, since the black original polyester fiber uses particles such as carbon black as a black original component, for example, as in Patent Document 1, there is a problem that the temperature of the fiber rises due to absorption of infrared rays when exposed to sunlight. It was.
In addition, Patent Document 2 provides a black original-strand having a reduced heat-absorbing property, which is colored with an infrared-transmitting perylene dye, but its use is limited for use in clothing and various industrial products. However, there was a problem that the texture could not be obtained. In addition, the perylene dye is an infrared transmissive black organic pigment, but exhibits good transmittance in a wavelength region of wavelength λ = 750 nm or more, but has a problem that infrared transmittance between wavelengths 680 to 750 nm is low. is there.

JP 2006-241640 A JP 2010-43401 A

  An object of the present invention is to solve the above-mentioned conventional problems, and by using an infrared transmission type black dye / pigment, it is excellent in blackness and has reduced heat absorption, for clothing and various industrial products. It is another object of the present invention to provide a black original polyester fiber that can be suitably used in the present invention.

The present invention relates to a black original polyester fiber characterized by containing 0.2 to 10% by weight of an infrared transmitting black dye / pigment and satisfying the following conditions (1) to (3).
(1) The average reflectance at 250 to 600 nm of the black original polyester fiber is 10% or less, the average transmittance at 1,000 to 2,000 nm is 30% or more, and the average absorbance is 50% or less. .
(2) The strength of the black original polyester fiber is 3.0 cN / dtex or more.
(3) The single yarn fineness of the black original polyester fiber is 0.5 to 5.0 dtex.
Here, an inorganic pigment may be used in combination with the black original polyester fiber of the present invention.
As the inorganic pigment, carbon black is preferably contained in an amount of 0.1% by weight or less based on the black original polyester fiber.
Next, the present invention relates to a fabric characterized in that any of the above-described black original polyester fibers is used at least in part, and the lightness (L ^* ) is 30 or less.

  The black original polyester fiber of the present invention uses an infrared transmission type black dye / pigment as a colorant, so that the temperature of the fiber is not easily raised upon irradiation with sunlight or irradiation including infrared rays. Furthermore, it is excellent in apparent blackness and has strength that can be suitably used for clothing and various industrial products.

  In the present invention, it is necessary to use an infrared transmitting dye / pigment as a colorant, and one or more of the following dyes / pigments may be used. Examples of the dye in the present invention include anthraquinone dyes, azo dyes, pyrazolone dyes, quinophthalone dyes, perinone dyes, methine dyes, and coumarin dyes. Moreover, as a pigment, the well-known organic and inorganic pigment currently used for coloring of a thermoplastic resin can be used. Examples of organic pigments include pyrrole, quinacridone, azo, dioxane, isoindolinone, indanthrene, quinophthalone, perinone, and phthalocyanine. Examples of the inorganic pigment include iron oxide, cadmium red, titanium yellow, cadmium yellow, ultramarine blue, bitumen, cobalt blue, cobalt green, and cerulean blue.

  When black is represented by a dyed pigment, there are some which become black by a combination of chromatic colors in addition to those exhibiting a single color black. Examples of pigments that are monochromatic and black and transmit near infrared rays include azomethiazo black pigments, and specific examples include Chromofine Black A-1103 manufactured by Dainichi Seika Kogyo. In addition, in order to make a chromatic and black color, it is colored with a black pigment such as carbon black by cutting the visible light region using yellow (Y), red (M), and indigo (C) with different absorption ranges. A black color equivalent to true black is obtained. Black can also be obtained by a combination of chromatic pigments or a combination of chromatic pigments and chromatic dyes. However, when pigments are used, near-infrared absorption increases, so it is preferable to obtain blacks by combining dyes. . For example, black can be expressed using Macrolex Yellow G, Macrolex Red EG, Macrolex Blue RR, and Macrolex Green 5B manufactured by LANXESS. It should be noted that the combination of dyes and pigments is not limited, such as adjusting the black color by combining a chromatic dye and a dye that exhibits a single black color. Specific examples thereof include Sumiplast Black HB and Sumiplast Black HLG manufactured by Sumika Chemtex, and Orazole Black RL manufactured by Ciba Specialty Chemicals.

The blending ratio of the dye / pigment needs to be 0.2 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the polyester. Preferably it is 5 weight part or less, More preferably, it is 2.5 weight part or less. This colorant (dye pigment) can be used singly or in combination. When the amount exceeds 10 parts by weight, the spinning property is deteriorated and spinning becomes difficult. In addition, when the amount is 2.5 parts by weight or less, the yarn forming property is improved, and a yarn having a small single yarn fineness can be produced. On the other hand, if the amount is less than 0.2 parts by weight, sufficient blackness cannot be obtained.
Further, the black original polyester fiber of the present invention needs to further satisfy the following requirements (1) to (3).

(1) The average reflectance at 250 to 600 nm of the black original polyester fiber of the present invention is 10% or less, the average transmittance at 1,000 to 2,000 nm is 30% or more, and the average absorbance is 50%. It is necessary that:
If the average reflectance in the visible light region of 250 to 600 nm exceeds 10%, sufficient blackness cannot be obtained. Preferably it is 8% or less, More preferably, it is 5% or less.
Moreover, when the average of the transmittance in the infrared region of 1,000 to 2,000 nm is less than 30% and the average of the absorptance exceeds 50%, a sufficient heat storage suppression effect cannot be obtained. Preferably, the average transmittance is 40% or more, the average absorption rate is 30% or less, more preferably the transmittance is 50% or more, and the average absorption rate is 20% or less.
Here, in order to reduce the average reflectance at 250 to 600 nm to 10% or less, it may be adjusted by combining dyes and pigments so as to absorb the visible light region. Moreover, what is necessary is just to adjust and mix | blend the content rate of the dye / pigment which has the function which permeate | transmits an infrared region, in order to make the average of the transmittance | permeability in 1,000-2,000 nm 30% or more. Furthermore, in order to make the average of the absorption rate 50% or less, since the absorption in the infrared region increases when a pigment is used, it is preferable to obtain black by adjusting the pigment content or by combining the dyes. .

(2) The strength of the black original polyester fiber needs to be 3.0 cN / dtex or more.
If it is less than 3.0 cN / dtex, it cannot be said that the strength can be suitably used for clothing and various industrial products. In order to increase the strength of the black original polyester fiber of the present invention to 3.0 cN / dtex or more, the strength decreases as the pigment content increases, so the pigment content may be adjusted.

  (3) The single yarn fineness of the black original polyester fiber is suitably in the range of 0.5 to 5 dtex (more preferably 1 to 4 dtex) in terms of texture. In order to set the single yarn fineness within the above range, for example, spinning may be performed using a die having a hole number of 36 or 72 to form a multifilament.

The blackness-adhering polyester fiber of the present invention can be adjusted in blackness by further using an inorganic pigment.
Examples of inorganic pigments include sulfide pigments such as carbon black, cadmium red, and cadmium yellow, silicate pigments such as ultramarine blue, titanium oxide, zinc white, petal, chromium oxide, iron black, titanium yellow, and zinc-iron. -Based brown, titanium-cobalt green, cobalt-green, cobalt-blue, oxide-based pigments such as copper-chromium black, copper-iron-based black, chromic pigments such as yellow lead, molybdate orange, ferrocyans such as bitumen System etc. Of these, titanium oxide, carbon black, cyanine, quinoline, anthraquinone, and phthalocyanine compounds are preferred, and carbon black, anthraquinone and phthalocyanine compounds are more preferred from the viewpoint of thermal stability.

The combined use of the inorganic pigment is originally performed for the purpose of adjusting the blackness. For example, a black pigment such as carbon black can be blended to intentionally lower the L ^* value. The amount of carbon black added for adjusting the hue is 0.1% by weight or less, preferably 0.05% by weight or less, based on the polyester fiber. If it exceeds 0.1% by weight, the obtained black original polyester fiber cannot obtain the effect of suppressing heat storage due to the heat storage effect of carbon black. In addition, when the amount is 0.05% by weight or less, the heat storage effect of carbon black is hardly exhibited, and thus black original polyester fibers having both black and heat storage suppression effects can be obtained.

  The polyester referred to in the present invention may be any as long as it forms fibers, such as polyethylene terephthalate, polytetramethylene terephthalate, poly-1,4-cyclohexylene dimethylene terephthalate, polyethylene-2, Preferable examples include 6-naphthalenedicarboxylate.

  These polyesters may be homopolyesters as described above, or may be copolyesters. In the case of copolyesters, those obtained by copolymerizing the above-mentioned homopolyester with a third component in a small proportion (for example, 20 mol% or less) are preferable. Examples of such third component include diethylene glycol, neopentyl glycol, and polyalkylene. Examples thereof include diol components such as glycol, and dicarboxylic acid components such as adipic acid, sebacic acid, phthalic acid, isophthalic acid, and 5-sodium sulfoisophthalic acid. Among these, polyethylene terephthalate having an intrinsic viscosity (measured at a temperature of 35 ° C. using orthochlorophenol as a solvent) of 0.5 to 0.95 dl / g is preferable.

  It is not necessary to adopt a special method for blending the infrared transmission type black dye / pigment of the present invention and other dyes / pigments in the polyester fiber. A method of kneading with a base polyester not containing carbon, and adding a liquid additive composition in which carbon black and liquid polyester are mixed in advance into a molten polyester flow just before spinning while measuring with a gear pump or the like, and then adding static or dynamic And a method of performing kneading and dispersing. Of these, the method using a master pellet is the most common in consideration of contamination of the spinning device, handling properties, cost, and the like.

  For example, the pellet made of the polyester resin composition mainly composed of the infrared transmission type black dye / pigment of the present invention and the fiber-forming polyester is not limited in any way, and is produced by a known pellet production method. Can be suitably used. That is, the resin composition placed in the form of a strand or plate is cut in the air or in water after the resin is completely solidified or not completely solidified and still in a molten state. These methods are conventionally known, but any of them can be suitably applied in the present invention.

The fiber process in the present invention is not particularly limited as long as it is a typical synthetic fiber fiberizing process, and the present invention is not limited to the production method described below. Specifically, according to a typical polyester melt spinning method, the prepared pellets are dried after crystallization as necessary, reduced to a level not hydrolyzed at the spinning stage, and then melt extruded with a single screw extruder. Then, it is weighed with a measuring gear pump, is continuously made into fibers by extruding the base, and solidified with cooling air, and then oil is applied and scraped off. The desired fiber is obtained by drawing and heat setting the pre-heated yarn. In some cases, stretching and heat setting may be performed directly after spinning. Moreover, you may produce a short fiber as needed by cutting to arbitrary length in the middle of the extending | stretching and a heat setting process, or after.
Further, the fibers to be scraped may have an arbitrary fiber cross-sectional shape as necessary, and may be selected as necessary, such as a round cross-section, a triangular cross-section, a cross cross-section, a hollow shape, a flat shape, and a hollow shape. In addition, in the fibers of the present invention, other modifiers and functional additives such as matting agents, antistatic agents, fluorescent brighteners, hygroscopic agents, ultraviolet absorbers, light stabilizers, antibacterial agents, You may contain in the range which does not impair the effect of this invention.

The spinning speed may be a general spinning speed, preferably 500 m / min to 5,000 m / min, and more preferably 1,000 m / min to 3,500 m / min.
The stretching temperature may be a preheating temperature at which the film can be stably stretched as long as it is equal to or higher than the glass transition temperature of the polymer, and is generally 60 ° C to 120 ° C, preferably 70 ° C to 100 ° C. Further, the draw ratio may be a draw ratio at which a desired drawn yarn elongation is obtained, and the original yarn elongation varies greatly depending on the spinning method, and is not particularly limited here, but generally ranges from 1.2 times to 5 times. Well, more preferably between 1.5 times and 4 times. The heat setting temperature is set for the purpose of heat-setting the drawn yarn and setting the heat shrinkage rate within the target range and stopping the change with time. So, if the temperature is higher than the temperature at which crystallization of the drawn yarn does not occur, the drawn yarn will be drawn. It may be selected according to the purpose of the yarn. Specifically, it is 110 to 200 ° C, more preferably 130 to 190 ° C. The stretching method in stretching is not particularly limited, and any method in which a shrinking operation is added to one-stage stretching, two-stage stretching, or three-stage multi-stage stretching may be used. In addition, by mixing with other fibers depending on the use of the yarn, a method of highlighting the characteristics when forming the fabric may be adopted, and false twisted yarn or drawn yarn wound in an intermediate orientation state may be adopted. Thus, mechanical properties such as design properties and crimp properties may be imparted.

The fiber and fiber structure of the present invention may be used alone as a fiber made of a resin composition, or may be mixed with other types of fibers. In addition to various combinations with fiber structures composed of other types of fibers, mixed modes include mixed yarns with other fibers, composite false twisted yarns, mixed spun yarns, long and short composite yarns, fluid processed yarns, covering yarns, and twisted yarns. Examples thereof include union, union, pile, pile, mixed cotton, mixed non-woven fabric of long fibers and short fibers, and felt. When mixed, in order to exhibit the characteristics of polyester, the mixed ratio is selected in the range of 1% by weight or more, more preferably 10% by weight or more, and further preferably 30% by weight or more.
Here, examples of other fibers to be mixed include cellulose fibers such as cotton, hemp, rayon, and tencel, wool, silk, acetate, polyester, nylon, acrylic, vinylon, polyolefin, and polyurethane.

  The fibers of the present invention can take the form of various fiber structures. Specifically, thread form products such as sewing threads, embroidery threads, strings, fabrics such as woven fabrics, knitted fabrics, nonwoven fabrics, felts, outer garments such as shirts, blousons, pants, coats, sweaters, uniforms, underwear, pantyhose, socks, lining , Interlining, sports clothing, women's clothing and high-value clothing products such as formal wear, clothing products such as cups and pads, curtains, carpets, chairs, mats, furniture, bags, furniture, wall materials, various belts Products for daily use such as bags and slings, as well as various textile products such as canvas, belts, nets, ropes, heavy cloth, bags, industrial materials such as felts and filters, vehicle interior products, and artificial leather products.

The lightness (L ^* ) of the fabric using at least part of the black original polyester fiber obtained in the present invention is 30 or less. When the lightness (L *) exceeds 30, it is difficult to say that the blackness is excellent. More preferably, it is 26 or less, More preferably, it is 20 or less. In order to set the lightness (L *) of this fabric to 30.0 or less, the infrared transmission type black dye / pigment of the present invention is added within the above range, or the dye / pigment that exhibits a black color with a chromatic dye / pigment. What is necessary is just to adjust by a combination.
Further, the a * of the fabric using at least part of the black original polyester fiber obtained in the present invention is preferably -5 to +10. When a * is out of the above range, it is difficult to say that the blackness is excellent. More preferably, it is -1 to +5.
Furthermore, the b * of the fabric using at least part of the black original polyester fiber obtained in the present invention is preferably -5 to +10. When b * is outside the above range, it is difficult to say that the blackness is excellent. More preferably, it is -1 to +5.
In order to set the above a * and b * within the above range, the infrared transmission type black dye / pigment of the present invention is added within the above range, or it is adjusted by a combination of a chromatic dye and a single color black dye. That's fine.

The invention is further illustrated by the following examples.
In the following examples and comparative examples, the following measurements and evaluations were performed.
(1) Intrinsic viscosity of polyester It calculated from the solution viscosity measured at 35 degreeC by using orthochlorophenol as a solvent. The unit is dl / g.
(2) Strength of fiber Measured according to JIS L-1013-75.
(3) Color measurement JIS Z 8729-1994, L ^* a ^* b ^* color system was measured using Macbeth (registered trademark) Color-Eye3100.
(4) Spectroscopic measurement It measured with the ultraviolet visible near-infrared spectrophotometer UV-3150 by Shimadzu Corporation. In the case of transmittance, air was measured as a blank, and in the case of diffuse reflectance, a barium sulfate standard white plate was measured as a blank.
(5) Thermal storage property It measured using illumination (IR100V / 125W) in the atmosphere of 20 degreeC and 65% RH. The sample used was obtained by making a 4 cm × 4 cm hole in cardboard and pasting the sample, and placing the sample on a 1 cm thick acrylic plate having an opening of 15 cm × 15 cm. The distance between the illumination and the sample was 30 cm, and the temperature on the back of the sample 15 minutes after the start of irradiation was measured.

[Example 1]
Using a polyethylene terephthalate tree having an intrinsic viscosity of 0.60 dl / g, a master batch having a content of 10% by weight of chromofine black A-1103 manufactured by Dainichi Seika Kogyo Co., Ltd., an infrared transmitting black pigment was produced. This master batch and the above-mentioned polyethylene terephthalate were mixed so that the pigment content would be 2% by weight, and a uniform material was used as a spinning raw material. This raw material was melted at 290 ° C., melt-spun at a spinning temperature of 290 ° C., a discharge rate of 42 g / min, and a spinning speed of 1,500 m / min from a spinning head having a nozzle with a number of holes of 36, and the undrawn yarn was wound up. . The obtained undrawn yarn was roller-drawn at a drawing temperature of 90 ° C. and a draw ratio of 3.3 times, and then heat-set with a non-contact heater at 180 ° C. to obtain a drawn yarn. In the drawing process, no fluff or yarn breakage occurred, and all undrawn yarns could be drawn without problems.
The obtained drawn yarn was 84 dtex / 36 fil, the single yarn fineness was 2.3 dtex, the strength was 3.5 cN / dtex, and the elongation was 27%. Cylinder knitting was made using this drawn yarn, and after refining and presetting, each measurement was performed. As a result of spectroscopic measurement, the average reflectance at 250 to 600 nm was 5%, the average transmittance at 1,000 to 2,000 nm was 35%, and the average absorbance was 40%. As a result of the color measurement, the L * value was 21.5, the a * value was 4.5, and the b * value was -4.3. Moreover, it was 57 degreeC as a result of evaluating heat storage property. The physical properties, blackness, and heat storage suppression effect of the obtained fiber were good.

[Example 2]
Sumiplast Black manufactured by Sumika Chemtex Co., Ltd., an infrared transmitting black dye using polyethylene terephthalate with an intrinsic viscosity of 0.60 dl / g
A masterbatch with a HB® PK3820 content of 10% by weight was produced. This master batch and the above-mentioned polyethylene terephthalate were mixed so that the pigment content would be 4% by weight, and a uniform material was used as a spinning material. Using this raw material in the same manner as in Example 1, a drawn yarn was obtained from a spinning head having a mouthpiece with 72 holes at a discharge rate of 22 g / min.
The obtained drawn yarn was 44 dtex / 72 fil, the single yarn fineness was 0.6 dtex, the strength was 3.8 cN / dtex, and the elongation was 23%. Cylinder knitting was made using this drawn yarn, and after refining and presetting, each measurement was performed. As a result of the spectroscopic measurement, the average reflectance at 250 to 600 nm was 5%, the average transmittance at 1,000 to 2,000 nm was 40%, and the average absorptance was 35%. As a result of the color measurement, the L * value was 17.5, the a * value was −0.4, and the b * value was −0.9. Moreover, it was 64 degreeC as a result of evaluating heat storage property. The physical properties, blackness, and heat storage suppression effect of the obtained fiber were good.

[Example 3]
Infrared transmission type black pigment similar to that in Example 1 and polyethylene black having an intrinsic viscosity of 0.60 dl / g were adjusted to 1% by weight of carbon black to reduce the L * value, and the pigment content was 20% by weight. A masterbatch was manufactured. This master batch and the above-mentioned polyethylene terephthalate were mixed so that the pigment content was 2.4% by weight, and a uniform material was used as a spinning raw material. A drawn yarn was obtained from this raw material in the same manner as in Example 1. The carbon content in the drawn yarn was 240 ppm.
The obtained drawn yarn was 84 dtex / 36 fil, the single yarn fineness was 2.3 dtex, the strength was 3.3 cN / dtex, and the elongation was 24%. Cylinder knitting was made using this drawn yarn, and after refining and presetting, each measurement was performed. As a result of spectroscopic measurement, the average reflectance at 250 to 600 nm was 4%, the average transmittance at 1,000 to 2,000 nm was 34%, and the average absorptance was 42%. As a result of color measurement, the L * value was 19.0, the a * value was −0.5, and the b * value was −2.4. Moreover, it was 61 degreeC as a result of evaluating heat storage property. The physical properties, blackness, and heat storage suppression effect of the obtained fiber were good.

[Comparative Example 1]
Using polyethylene terephthalate having an intrinsic viscosity of 0.60 dl / g, a masterbatch having an infrared transmission black pigment content of 20% by weight similar to that of Example 1 was produced. This master batch and the above-mentioned polyethylene terephthalate were mixed so that the pigment content was 12% by weight, and the mixture was made uniform to be used as a spinning raw material. This material was melted at 290 ° C. and melt spinning was attempted from a spinning head having a nozzle with 36 holes at a spinning temperature of 290 ° C., a discharge rate of 42 g / min and a spinning speed of 1,500 m / min. Because of the poor, winding was impossible.

[Comparative Example 2]
A polyethylene terephthalate having an intrinsic viscosity of 0.60 dl / g was used as a spinning raw material, and the pigment content was adjusted to 0.1% by weight in the same manner as in Example 1 to obtain a drawn yarn.
The obtained drawn yarn was 84 dtex / 36 fil, the single yarn fineness was 2.3 dtex, the strength was 4.8 cN / dtex, and the elongation was 26%. Cylinder knitting was made using this drawn yarn, and after refining and presetting, each measurement was performed. As a result of the spectroscopic measurement, the average reflectance at 250 to 600 nm was 35%, the average transmittance at 1,000 to 2,000 nm was 25%, and the average absorbance was 8%. As a result of the color measurement, the L * value was 48.0, the a * value was −3.5, and the b * value was −2.6. Moreover, it was 50 degreeC as a result of evaluating heat storage property.

[Comparative Example 3]
A master batch having a carbon black content of 16% by weight was produced using polyethylene terephthalate having an intrinsic viscosity of 0.60 dl / g. This master batch and the above-mentioned polyethylene terephthalate were mixed so that the pigment content was 2.4% by weight, and a uniform material was used as a spinning raw material. A drawn yarn was obtained from this raw material in the same manner as in Example 1.
The obtained drawn yarn was 84 dtex / 36 fil, the single yarn fineness was 2.3 dtex, the strength was 4.1 cN / dtex, and the elongation was 38%. Cylinder knitting was made using this drawn yarn, and after refining and presetting, each measurement was performed. As a result of the spectroscopic measurement, the average reflectance at 250 to 600 nm was 2.5%, the average transmittance at 1,000 to 2,000 nm was 20%, and the average absorptance was 75%. As a result of color measurement, the L * value was 17.4, the a * value was -0.1, and the b * value was -1.2. Moreover, it was 106 degreeC as a result of evaluating heat storage property. Although the physical properties and blackness of the obtained fiber were good, the temperature at 106 ° C. and the temperature on the back of the fabric increased, and heat was stored.

[Comparative Example 4]
Using polyethylene terephthalate having an intrinsic viscosity of 0.60 dl / g, the same infrared transmissive black pigment as in Example 1 was adjusted with 5% by weight of carbon black to reduce the L * value, and the pigment content was 20% by weight. A masterbatch was produced. This master batch and the above-mentioned polyethylene terephthalate were mixed so that the pigment content was 2.4% by weight, and a uniform material was used as a spinning raw material. A drawn yarn was obtained from this raw material in the same manner as in Example 1. The carbon content in the drawn yarn was 1,200 ppm.
The obtained drawn yarn was 84 dtex / 36 fil, the strength was 3.2 cN / dtex, and the elongation was 33%. Cylinder knitting was made using this drawn yarn, and after refining and presetting, each measurement was performed. As a result of the spectroscopic measurement, the average reflectance at 250 to 600 nm was 3.5%, the average transmittance at 1,000 to 2,000 nm was 23%, and the average absorptance was 65%. As a result of the color measurement, the L * value was 18.2, the a * value was −0.4, and the b * value was −2.0. Moreover, it was 105 degreeC as a result of evaluating heat storage property. Although the physical properties and blackness of the obtained fiber were good, the heat storage property was further increased by adding carbon as compared with Example 3, and the temperature on the back of the fabric increased to 105 ° C. .

  The black original polyester fiber of the present invention uses an infrared transmission type black dye / pigment as a colorant, so that the temperature of the fiber is not easily raised upon irradiation with sunlight or irradiation including infrared rays. Furthermore, it is excellent in apparent blackness and has strength, heat resistance, and light resistance that can be suitably used for clothing and various industrial products. Therefore, it is useful for applications such as clothes, car interiors, and interiors.

Claims (4)

A black original polyester fiber comprising 0.2 to 10% by weight of an infrared transmitting black dye / pigment and satisfying the following conditions (1) to (3):
(1) The average reflectance at 250 to 600 nm of the black original polyester fiber is 10% or less, the average transmittance at 1,000 to 2,000 nm is 30% or more, and the average absorbance is 50% or less. .
(2) The strength of the black original polyester fiber is 3.0 cN / dtex or more.
(3) The single yarn fineness of the black original polyester fiber is 0.5 to 5.0 dtex.   The black original polyester fiber according to claim 1, wherein an inorganic pigment is used in combination.   3. The black original polyester fiber according to claim 1, wherein carbon black is contained as an inorganic pigment in an amount of 0.1% by weight or less based on the black original polyester fiber. A fabric characterized in that the black original polyester fiber according to any one of claims 1 to 3 is used at least in part, and the lightness (L ^* ) is 30 or less.