INFRARED-ABSORBING FIBER, KNIT FABRIC, OR NON-WOVEN FABRIC

Abstract

 Provided is an infrared-absorbing fiber, knit fabric, or non-woven fabric containing an infrared-absorbing pigment, wherein L^∗ in the CIE 1976 color space is at least 30, and the color difference ΔE in the CIE 1976 color space between said infrared-absorbing fiber, knit fabric, or non-woven fabric and an infrared-absorbing fiber, knit fabric, or non-woven fabric containing no infrared-absorbing pigment is at most 10.

Description

FIELD

[0001] The present invention relates to an infrared absorbent fiber, knit/woven fabric, or nonwoven fabric.

BACKGROUND

[0002] Textile products having the property of absorbing light to generate heat are known. For example, an infrared absorbing pigment such as carbon black has the property of absorbing infrared radiation to generate heat, and is thus kneaded into or applied to fibers to obtain exothermic fibers.

[0003] However, there is an issue with fibers comprising carbon black as an infrared absorbing pigment in which the color tone becomes extremely dark due to the black color of carbon black, and thus a design having a bright color tone cannot be applied.

[0004] In this regard, PTL 1 discloses an infrared absorbent fiber containing composite tungsten oxide microparticles typified by Cs_0.33WO₃ as an infrared absorbing pigment, wherein the content of the microparticles is 0.001 to 80% by weight with respect to the solid content of the fiber.

[0005] When compared with the black color of carbon black, a composite tungsten oxide has a bright color tone. Therefore, a textile product containing a composite tungsten oxide has an advantage in the degree of freedom in design as compared with a textile product containing carbon black.

[CITATION LIST]

[PATENT LITERATURE]

[0006] [PTL 1] Japanese Unexamined Patent Publication (Kokai) No. 2006-132042

SUMMARY

[TECHNICAL PROBLEM]

[0007] Composite tungsten oxides, for example, Cs_0.33WO₃ (hereinafter, referred to as CsWO) exhibit a light bluish green color which can be visually recognized under visible light. When applied to a textile product having a bright color tone, the color tone of the textile product thus obtained may change.

[0008] Generally, in exothermic cold-proofing garments, it is not necessary for a garment to be composed entirely of an exothermic textile product. The exothermic textile product is used only in portions of the garment where heat generation contributes to cold proofing, with other portions composed of ordinary textile products. At this time, when a textile product comprising CsWO is used as an exothermic textile product, a difference in color tone may occur between the portions comprising CsWO and the portions not comprising CsWO, which may cause a design issue. This tendency is remarkable when the intended garment has a particularly bright color tone.

[0009] According to PTL 1, the CsWO content in the infrared absorbent fiber is 0.001 to 80% by weight with respect to the solid content of the fiber, which is an unreasonably wide range and encompasses cases in which the exothermic property is insufficient and cases in which the exothermic property is excessive when used in cold-proofing garments.

[0010] The present invention has been made in view of the above circumstances. Therefore, an object of the present invention is to provide a fiber, knit/woven fabric, or nonwoven fabric containing an infrared absorbing pigment and having a property of absorbing infrared radiation to generate heat, capable of providing preferable designability when applied to garment articles such as cold-proofing garments.

[SOLUTION TO PROBLEM]

[0011] The present invention for achieving the above object is described as follows.

[0012] 

<<Aspect 1>> An infrared absorbent fiber, knit/woven fabric, or nonwoven fabric comprising an infrared absorbing pigment,

wherein L^∗ in CIE 1976 color space is 30 or greater, and

a color difference ΔE in the CIE 1976 color space between the infrared absorbent fiber, knit/woven fabric, or nonwoven fabric and the infrared absorbent fiber, knit/woven fabric, or nonwoven fabric not comprising the infrared absorbing pigment is 10 or less.

<<Aspect 2>> The infrared absorbent fiber, knit/woven fabric, or nonwoven fabric according to Aspect 1, wherein the L^∗ in the CIE 1976 color space is greater than 90, and at least one of (i) to (iv) below is satisfied:

(i) a^∗ in the CIE 1976 color space is -10 or less,

(ii) a^∗ in the CIE 1976 color space is 10 or greater,

(iii) b^∗ in the CIE 1976 color space is -10 or less, and

(iv) b^∗ in the CIE 1976 color space is 10 or greater.

<<Aspect 3>> The infrared absorbent fiber, knit/woven fabric, or nonwoven fabric according to Aspect 1, wherein the L^∗ in the CIE 1976 color space is 90 or less.

<<Aspect 4>> The infrared absorbent fiber, knit/woven fabric, or nonwoven fabric according to any one of Aspects 1 to 3,
wherein the infrared absorbent fiber has a content of the infrared absorbing pigment of 0.01% by mass or greater and 0.50% by mass or less based on a total mass of the infrared absorbent fiber, and
the infrared absorbent knit/woven fabric or nonwoven fabric has a content of the infrared absorbing pigment of 0.05 g/m² or greater and 0.50 g/m² or less per area of the infrared absorbent knit/woven fabric or nonwoven fabric.

<<Aspect 5>> The infrared absorbent fiber, knit/woven fabric, or nonwoven fabric according to any one of Aspects 1 to 4,

wherein the infrared absorbing pigment comprises at least one or more selected from the group consisting of

a composite tungsten oxide, represented by

        general formula M_xW_yO_z     (1)

wherein M is one or more elements selected from the group consisting of H, He, alkali metals, alkaline earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; W is tungsten; O is oxygen; x, y, and z are each a positive number; 0 < x/y ≤ 1; and 2.2 ≤ z/y ≤ 3.0, and

a tungsten oxide having a Magnéli phase, represented by

        general formula W_yO_z     (2)

wherein W is tungsten; O is oxygen; y and z are each a positive number; and 2.45 ≤ z/y ≤ 2.999.

<<Aspect 6>> The infrared absorbent fiber according to any one of Aspects 1 to 5.

<<Aspect 7>> An infrared absorbent knit/woven fabric or nonwoven fabric, composed of the infrared absorbent fiber according to Aspect 6.

<<Aspect 8>> An infrared absorbent knit/woven fabric or nonwoven fabric, composed of the infrared absorbent fiber according to Aspect 6 and a fiber free of any infrared absorbing pigment,
wherein the fiber free of any infrared absorbing pigment is configured such that the infrared absorbing pigment is removed from the infrared absorbent fiber.

<<Aspect 9>> The infrared absorbent knit/woven fabric or nonwoven fabric according to any one of Aspects 1 to 5.

<<Aspect 10>> The infrared absorbent knit/woven fabric or nonwoven fabric according to Aspect 9, composed of the infrared absorbent fiber comprising the infrared absorbing pigment.

<<Aspect 11>> The infrared absorbent knit/woven fabric or nonwoven fabric according to Aspect 9, composed of the infrared absorbent fiber comprising the infrared absorbing pigment and a fiber free of any infrared absorbing pigment,
wherein the fiber free of any infrared absorbing pigment is configured such that the infrared absorbing pigment is removed from the infrared absorbent fiber.

<<Aspect 12>> An infrared absorbent clothing, composed of the infrared absorbent knit/woven fabric or nonwoven fabric according to any one of Aspects 7 to 11.

<<Aspect 13>> An infrared absorbent clothing, composed of the infrared absorbent knit/woven fabric or nonwoven fabric according to any one of Aspects 7 to 11 and a knit/woven fabric or nonwoven fabric free of any infrared absorbing pigment,
wherein the knit/woven fabric or nonwoven fabric free of any infrared absorbing pigment is configured such that the infrared absorbing pigment is removed from the infrared absorbent fabric or nonwoven fabric.

[ADVANTAGEOUS EFFECTS OF INVENTION]

[0013] According to the present invention, a fiber, knit/woven fabric, or nonwoven fabric containing an infrared absorbing pigment and having a property of absorbing infrared radiation to generate heat, capable of providing preferable designability when applied to garment articles such as cold-proofing garments is provided.

DESCRIPTION OF EMBODIMENTS

[0014] The infrared absorbent fiber, knit/woven fabric, or nonwoven fabric of the present invention is an infrared absorbent fiber, knit/woven fabric, or nonwoven fabric comprising an infrared absorbing pigment,

wherein L^∗ in the CIE 1976 color space is 30 or greater, and

the color difference ΔE in the CIE 1976 color space between the infrared absorbent fiber, knit/woven fabric, or nonwoven fabric and the infrared absorbent fiber, knit/woven fabric, or nonwoven fabric not comprising the infrared absorbing pigment is 10 or less.

[0015] The infrared absorbent fiber, knit/woven fabric, or nonwoven fabric of the present invention may further be an infrared absorbent fiber, knit/woven fabric, or nonwoven fabric
wherein L^∗ in the CIE 1976 color space is greater than 90, and at least one of the following (i) to (iv) below is satisfied:

(i) a^∗ in the CIE 1976 color space is -10 or less,

(ii) a^∗ in the CIE 1976 color space is 10 or greater,

(iii) b^∗ in the CIE 1976 color space is -10 or less, and

(iv) b^∗ in the CIE 1976 color space is 10 or greater.

[0016] The infrared absorbent fiber, knit/woven fabric, or nonwoven fabric may otherwise be an infrared absorbent fiber, knit/woven fabric, or nonwoven fabric
wherein L^∗ in the CIE 1976 is 90 or less.

[0017] Herein, "knit/woven fabric" is a concept that includes both cloth (woven fabric) and knit (knit fabric). "Nonwoven fabric" means a sheet-like material in which fibers are entangled, and is a concept that does not include woven fabric or knit fabric. Hereinafter, fiber, knit/woven fabric, and nonwoven fabric are collectively referred to as "textile product".

[0018] Herein, having an L^∗ of 30 or greater in the CIE 1976 color space of an infrared absorbent textile product is referred to as the "L^∗ requirement", and having a color difference ΔE of 10 or less in the CIE 1976 color space between an infrared absorbent textile product and the infrared absorbent textile product when not comprising the infrared absorbing pigment is referred to as the "ΔE requirement".

[0019] The color difference ΔE, when a color in the CIE 1976 color space of the infrared absorbent textile product is set as (L^∗, a^∗, b^∗) and a color in the CIE 1976 color space of the infrared absorbent textile product when not comprising an infrared absorbing pigment is set as (L₀^∗, a₀^∗, b₀^∗), is a value represented by the following formula:

[0020] The present inventors, in order to achieve the object of the present invention, have investigated in detail the relationship between

the color tone of a textile product when not comprising an infrared absorbing pigment,

the amount of the infrared absorbing pigment contained in the textile product,

the change in color tone of the textile product when comprising a predetermined amount of the infrared absorbing pigment, and

the exothermic property of the textile product when comprising the predetermined amount of the infrared absorbing pigment.

[0021] As a result, the following was found:

(1) In textile products having a dark color tone, the change in color tone of a textile product between when not comprising an infrared absorbing pigment and when comprising the infrared absorbing pigment is small enough not to cause any issues,

(2) of textile products having a bright color tone, particularly a bright color, the change in color tone due to the inclusion of an infrared absorbing pigment is easier to identify visually in textile products with low chroma than in colorful textile products with high chroma, and

(3) textile products having a bright color tone, comprising an infrared absorbing pigment in an amount such that the change in color tone is difficult to identify, demonstrates a comfortable heat generation as cold-proofing garments.

[0022] The present invention has been made based on the above findings.

[0023] In the infrared absorbent textile product of the present invention, when L^∗ in the CIE 1976 color space is 30 or greater, by comprising a significant amount of the infrared absorbing pigment, the color tone of the textile product is so bright that the change in color tone becomes an issue. Therefore, textile products having a dark color tone with an L^∗ of less than 30, wherein the change in color tone is difficult to identify even if a significant amount infrared absorbing pigment is contained, are excluded from the scope of the present invention.

[0024] In the infrared absorbent textile product of the present invention, when the color difference ΔE in the CIE 1976 color space between when the infrared absorbing pigment is contained and not contained is 10 or less, the color difference indicates that the textile product comprises the infrared absorbing pigment in an amount such that the change in color tone is difficult to identify. A textile product satisfying this requirement can have a comfortable heat generation as a cold-proofing garment, in addition to reducing the difference in color tone from portions not comprising the infrared absorbing pigment, and preferable designability can be demonstrated thereby.

[0025] When the color tone of the infrared absorbent textile product of the present invention is particularly bright, by comprising the infrared absorbing pigment, the change in color tone of the infrared absorbent textile product becomes easy to identify visually. Considering this, when the color tone of the textile product is particularly bright, it is advantageous to have a high chroma from the viewpoint of making the visual identification of the change in color tone difficult. Therefore, when the infrared absorbent textile product of the present invention is particularly bright, for example, when L^∗ in the CIE 1976 color space is greater than 90, it is preferable that at least one of the following requirements (i) to (iv) be satisfied:

(i) a^∗ in the CIE 1976 is -10 or less,

(ii) a^∗ in the CIE 1976 is 10 or greater,

(iii) b^∗ in the CIE 1976 is -10 or less, and

(iv) b^∗ in the CIE 1976 is 10 or greater.

[0026] However, when the infrared absorbent textile product of the present invention is not particularly bright, for example, when L^∗ in the CIE 1976 color space is 90 or less, the change in color tone due to the inclusion of the infrared absorbing pigment is not particularly easy to identify visually. Therefore, in this case, the present invention can be suitably adapted regardless of the value of a^∗ or b^∗.

[0027] In the CIE 1976 color space, the L^∗, a^∗, and b^∗ of the textile product can be measured by the method described later in the Examples.

[0028] Hereinafter, the present invention will be described in detail.

«Infrared absorbent textile product»

[0029] The infrared absorbent textile product of the present invention is

an infrared absorbent textile product comprising an infrared absorbing pigment,

wherein L^∗ in the CIE 1976 color space is 30 or greater, and

the color difference ΔE in the CIE 1976 color space between the infrared absorbent textile product and the infrared absorbent textile product when not comprising the infrared absorbing pigment is 10 or less.

[0030] The infrared absorbent textile product of the present invention may also be
an infrared absorbent textile product wherein L^∗ in the CIE 1976 color space is greater than 90, and at least one of the following (i) to (iv) is satisfied:

(i) a^∗ in the CIE 1976 color space is -10 or less,

(ii) a^∗ in the CIE 1976 color space is 10 or greater,

(iii) b^∗ in the CIE 1976 color space is -10 or less, and

(iv) b^∗ in the CIE 1976 color space is 10 or greater.

[0031] The infrared absorbent textile product of the present invention may otherwise be an infrared absorbent textile product
wherein L^∗ in the CIE 1976 color space is 90 or less.

[0032] The color difference ΔE in the CIE 1976 color space between the infrared absorbent textile product and the infrared absorbent textile product when not comprising the infrared absorbing pigment is 10 or less. When the ΔE therebetween is 10 or less, the change in color tone due to the textile product comprising the infrared absorbing pigment becomes difficult to identify visually. The value of ΔE may be 9 or less, 8 or less, 6 or less, 5 or less, or 4 or less. Further, the value of ΔE may be 0 or greater, greater than 0, 0.5 or greater, 1 or greater, 2 or greater, or 3 or greater.

[0033] In the infrared absorbent textile product, even when L^∗ in the CIE 1976 color space is greater than 90, i.e., when the color tone of the textile product is particularly bright, if at least one of the above (i) to (iv) is satisfied, the change in color tone due to the textile product comprising the infrared absorbing pigment can be made difficult to identify visually. When L^∗ is greater than 90, the color difference ΔE may be 5 or less, 4.5 or less, 4 or less, 3.5 or less, or 3 or less, and may be 0 or greater, greater than 0, 0.1 or greater, 0.2 or greater, 0.3 or greater, 0.4 or greater, or 0.5 or greater, from the viewpoint of making the visual identification of the change in color tone difficult.

[0034] However, when L^∗ is greater than 90, in an effort to ensure the difficulty of visually identifying the change in color tone, the content of the infrared absorbing pigment in the textile product may be limited, and thus the exothermic property may be limited. From this viewpoint, L^∗ in the CIE 1976 color space of the infrared absorbent textile product may be 90 or less.

[0035] The L^∗ is appropriately set to the ranges described above depending on the desired color tone of the textile product. For example, when the textile product has a reddish color tone, L^∗ is 90 or less, and may be 80 or less, 70 or less, 60 or less, or 50 or less. When the textile product has a yellowish color tone, L^∗ is 90 or less, and may be 89 or less, 88 or less, 87 or less, or 86 or less. When the textile product has a bluish color tone, L^∗ is 90 or less, and may be 80 or less, 60 or less, or 40 or less.

[0036] When L^∗ is 90 or less, and the color tone of the textile product is relatively bright, for example when L^∗ is greater than 80, the color difference ΔE may be set to 8 or less, 7 or less, 6 or less, or 5 or less in order to ensure the difficulty of visually identifying the change in color tone. When L^∗ is 80 or less, visually identifying the change in color tone becomes extremely difficult if the color difference ΔE is 10 or less.

<Fiber>

[0037] The infrared absorbent textile product of the present invention comprises a fiber and an infrared absorbing pigment.

[0038] The fiber in the infrared absorbent textile product of the present invention may be appropriately selected from, for example, synthetic fiber, semi-synthetic fiber, natural fiber, produced fiber, inorganic fiber, and a blended yarn composed of a plurality of types thereof. Of these, synthetic fiber is preferable when considering the dispersibility of the infrared absorbing pigment and heat-insulating characteristic of the textile product.

[0039] Examples of the synthetic fiber in the present invention include polyester fiber, polyolefin fiber, acrylic fiber, polyamide fiber, polyether ester fiber, polyvinyl alcohol fiber, polyvinylidene chloride fiber, and polyvinyl chloride fiber. These may be appropriately selected and used.

[0040] The polyester fiber may include fibers of, for example, polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate.

[0041] The polyolefin fiber may include fibers of, for example, polyethylene, polypropylene, and polystyrene.

[0042] The acrylic fiber may include fibers consisting of, for example, polyacrylonitrile and an acrylonitrile/vinyl chloride copolymer.

[0043] The polyamide fiber may include fibers consisting of, for example, nylon, nylon 6, nylon 66, nylon 11, nylon 12, nylon 610, and aramid.

[0044] The fiber of the present invention may have a cross-section of any shape, for example, a circular, polygonal, flat, hollow, Y, star, or core-sheath shape.

[0045] The fiber of the present invention may be a short fiber or a long fiber.

<Infrared absorbing pigment>

[0046] It is preferable for the infrared absorbing pigment in the infrared absorbent textile product of the present invention to have the properties of absorbing infrared radiation, preferably near-infrared radiation, and emitting heat, along with having a bright color tone, and not to excessively impair the degree of freedom on the design face of the infrared absorbent textile product of the present invention.

[0047] Examples of such an infrared absorbing pigment may include a composite tungsten oxide, represented by

        general formula M_xW_yO_z     (1)

wherein M is one or more elements selected from the group consisting of H, He, alkali metals, alkaline earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; W is tungsten; O is oxygen; x, y, and z are each a positive number; 0 < x/y ≤ 1; and 2.2 ≤ z/y ≤ 3.0, and
a tungsten oxide having a Magnéli phase, represented by

        general formula W_yO_z     (2)

wherein W is tungsten; O is oxygen; y and z are each a positive number; and 2.45 ≤ z/y ≤ 2.999. From these, one or more may be appropriately selected are used.

[0048] The alkali metal herein is a Group 1 element of the periodic table except hydrogen. The alkaline earth metal is a Group 2 element of the periodic table except Be and Mg. The rare earth element includes Sc, Y, and lanthanoid elements.

[0049] The composite tungsten oxide represented by the general formula (1) comprises an element M. Since free electrons are generated and the absorption band from the free electrons is expressed in the near-infrared wavelength region, the composite tungsten oxide is suitable as a material that absorbs near-infrared radiation having a wavelength near 1,000 nm to generate heat.

[0050] When the value of x/y indicating the addition amount of the element M is greater than 0, a sufficient amount of free electrons are generated and a sufficient near-infrared absorption effect can be obtained. As the addition amount of the element M increases, the supply of free electrons increases, and the near-infrared absorption effect also increases. However, the effect saturates at an x/y value of about 1. It is preferable for the value of x/y to be 1 or less since the formation of an impurity phase in a microparticle-containing layer can be avoided. The value of x/y is preferably 0.001 or greater, 0.2 or greater, or 0.30 or greater, and is preferably 0.85 or less, 0.5 or less, or 0.35 or less. Ideally, the value of x/y is 0.33.

[0051] Particularly, it is preferable that the element M in the general formula (1) be one or more of Cs, Tb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn, from the viewpoint of improving the optical characteristics as a near-infrared absorbent material and weather resistance. It is particularly preferable that M be Cs.

[0052] In the case of Cs_xW_yO_z (0.25 ≤ x/y ≤ 0.35, 2.2 ≤ z/y ≤ 3.0), it is preferable that the lattice constants be 7.4060 Å or greater and 7.4082 Å or less for the a-axis and 7.6106 Å or greater and 7.6149 Å or less in the c-axis, from the viewpoint of optical characteristics in the near-infrared region and weather resistance.

[0053] It is preferable that the composite tungsten oxide represented by the general formula (1) have a hexagonal crystal structure or consist of a hexagonal crystal structure, since the transmission of the infrared absorbent material microparticles in the visible light wavelength region is improved and the absorption in the near-infrared light wavelength region is improved. When cations of the element M are added and positioned in the voids of the hexagonal crystal, the transmission in the visible light wavelength region is improved and the absorption in the near-infrared light wavelength region is improved. Generally, when an element M having a large ionic radius is added, hexagonal crystals are formed. Specifically, when an element having a large ionic radius, such as Cs, Rb, K, Tl, In, Ba, Sn, Li, Ca, Sr, or Fe, is added, it is easy to form hexagonal crystals. However, the present invention is not limited to these elements. Even for elements other than the ones above, the additive element M may be present in the hexagonal voids formed in the WO₆ units.

[0054] When the composite tungsten oxide having a hexagonal crystal structure has a uniform crystal structure, the addition amount of the additive element M preferably has an x/y value of 0.2 or greater and 0.5 or less, more preferably 0.30 or greater and 0.35 or less, and ideally 0.33. By setting the value of x/y to 0.33, it is considered that the additive element M is positioned in all of the hexagonal voids.

[0055] It is preferable that the composite tungsten oxide represented by the general formula (1) be treated with a silane coupling agent, since the composite tungsten oxide is imparted with excellent dispersibility, near-infrared absorption, and transparency in the visible light wavelength region.

[0056] In the tungsten oxide having a Magnéli phase represented by the general formula (2), the so-called "Magnéli phase" having a composition ratio in which the z/y value satisfies the relationship of 2.45 ≤ z/y ≤ 2.999 is chemically stable and has good absorption characteristic in the near-infrared light wavelength region, and is thus preferable as a near-infrared absorbent material.

[0057] In the general formulas (1) and (2), the z/y value indicates the level of oxygen control. For the composite tungsten oxide represented by the general formula (1), since the z/y value satisfies the relationship of 2.2 ≤ z/y ≤ 3.0, free electrons are supplied by the addition of the element M even when z/y = 3.0, in addition to the same oxygen control mechanism as in the tungsten oxide represented by the general formula (2). Thus, it is more preferable that the z/y value satisfy the relationship of 2.45 ≤ z/y ≤ 3.0 in the general formula (1).

[0058] The oxygen atoms constituting the composite tungsten oxide and tungsten oxide may be partially substituted with halogen atoms derived from the starting compounds used during the production of the composite tungsten oxide and the tungsten oxide in the present invention, and such substitution is not an issue in the embodiment of the present invention. Therefore, the composite tungsten oxide and the tungsten oxide in the present invention include those in which the oxygen atoms have been partially substituted with halogen atoms.

[0059] For the infrared absorbing pigment of the present invention, the transparent color tone thereof is often bluish to greenish due to significant absorption of light in the near-infrared light wavelength region, particularly near the wavelength of 1,000 nm. However, since the developed color is pale, the infrared absorbent textile product of the present invention comprising the infrared absorbing pigment is able to provide preferable designability when applied to garment articles such as cold-proofing garments.

[0060] The content of the infrared absorbing pigment in the infrared absorbent textile product of the present invention will be described later.

<Infrared absorbent fiber>

[0061] The infrared absorbent textile product of the present invention includes an infrared absorbent fiber.

[0062] Therefore, the infrared absorbent fiber of the present invention is

an infrared absorbent fiber comprising an infrared absorbing pigment,

wherein L^∗ in the CIE 1976 color space is 30 or greater, and

the color difference ΔE in the CIE 1976 color space between the infrared absorbent fiber and the infrared absorbent fiber when not comprising the infrared absorbing pigment is 10 or less.

[0063] Herein, the color tone of the fiber may be measured in a state where the fiber is made into a plain weave or a tricot fabric.

[0064] The content of the infrared absorbing pigment in the infrared absorbent fiber of the present invention may be 0.01% by mass or greater and 0.50% by mass or less, based on the total mass of the infrared absorbent fiber.

[0065] The suitable content of the infrared absorbing pigment for achieving comfortable heat generation while satisfying the predetermined ΔE requirement of the present invention may be 0.01% by mass or greater, 0.05% by mass or greater, 0.10% by mass or greater, or 0.15% by mass or greater, and 0.50% by mass or less, 0.40% by mass or less, 0.30% by mass or less, or 0.20% by mass or less, based on the total mass of the infrared absorbent fiber.

<Method for producing infrared absorbent fiber>

[0066] The infrared absorbent fiber of the present invention may be produced by a known appropriate method or an appropriate modification thereof by a person skilled in the art.

[0067] The infrared absorbent fiber of the present invention may be produced by a method such as:

(1) a method of spinning in which an infrared absorbing pigment is directly blended with a starting polymer of a synthetic fiber;

(2) a method of spinning in which a masterbatch is produced by blending an infrared absorbing pigment at a high concentration with a starting polymer of a synthetic fiber, and the masterbatch is mixed with a diluted polymer free of any infrared absorbing pigment;

(3) a method of spinning in which an infrared absorbing pigment is blended into a dope solution containing a starting polymer of a synthetic fiber; and

(4) a method of attaching an infrared absorbing pigment to at least one of a surface and an inner portion of a fiber free of any infrared absorbing pigment.

[0068] The spinning in the above production methods (1), (2), and (3) may be wet spinning using an appropriate solvent or dry spinning such as melt spinning.

[0069] The infrared absorbent fiber of the present invention may comprise a coloring agent such as an appropriate pigment or dye, in order to express a predetermined color tone. The coloring agent may be added at any point in the production process of the infrared absorbent fiber.

<Application of infrared absorbent fiber>

[0070] The infrared absorbent fiber of the present invention may be applied to, for example, an infrared absorbent knit/woven fabric or nonwoven fabric.

[0071] The infrared absorbent knit/woven fabric or nonwoven fabric may be composed of only the infrared absorbent fiber of the present invention, or may be composed of the infrared absorbent fiber of the present invention and another fiber. The other fiber may be a fiber comprising an infrared absorbing pigment without satisfying at least one of the predetermined L^∗ and ΔE requirements of the present invention, or may be a fiber free of any infrared absorbing pigment.

[0072] It is preferable that a fiber configured such that the infrared absorbing pigment is removed from the infrared absorbent fiber of the present invention be used as the other fiber, in order to achieve the goal of the present invention to provide preferable designability when applied to garment articles.

[0073] It is preferable that the infrared absorbent knit/woven fabric or nonwoven fabric composed of the infrared absorbent fiber of the present invention be

composed of only the infrared absorbent fiber of the present invention, or

composed of the infrared absorbent fiber of the present invention and a fiber configured such that the infrared absorbing pigment is removed from the infrared absorbent fiber.

[0074] It is satisfactory if the infrared absorbent fiber of the present invention satisfies both of the predetermined L^∗ and ΔE requirements of the present invention. The infrared absorbent knit/woven fabric or nonwoven fabric composed of the infrared absorbent fiber of the present invention, as a whole knit/woven fabric or nonwoven fabric, may satisfy both of the predetermined L^∗ and ΔE requirements of the present invention, or may not satisfy at least one of these requirements.

[0075] Examples of the infrared absorbent knit/woven fabric or nonwoven fabric composed of the infrared absorbent fiber of the present invention may include woven fabrics such as plain weave, satin weave, and twill weave;

knit fabrics (knit) such as chain stitch, single crochet stitch, ridge stitch, double crochet stitch, half-double crochet stitch, slip stitch, tricot; and

nonwoven fabrics produced by appropriate methods such as dry-laid method, wet-laid method, spun-bonding method, melt-blowing method, thermal bonding method, chemical bonding method, needle-punching method, spunlace method, stitch-bonding method, and steam jet method.

<Infrared absorbent knit/woven fabric and nonwoven fabric>

[0076] The infrared absorbent textile product of the present invention includes infrared absorbent knit/woven fabric and nonwoven fabric. Hereinafter, the knit/woven fabric and nonwoven fabric are collectively referred to as "knit/woven/nonwoven fabric".

[0077] The infrared absorbent knit/woven/nonwoven fabric of the present invention is

an infrared absorbent knit/woven/nonwoven fabric comprising an infrared absorbing pigment,

wherein L^∗ in the CIE 1976 color space is 30 or greater, and

the color difference ΔE in the CIE 1976 color space between the infrared absorbent knit/woven/nonwoven fabric and the infrared absorbent knit/woven/nonwoven fabric not comprising the infrared absorbing pigment is 10 or less.

[0078] The content of the infrared absorbing pigment in the infrared absorbent knit/woven/nonwoven fabric of the present invention may be 0.05 g/m² or greater and 0.50 g/m² or less per area of the infrared absorbent knit/woven/nonwoven fabric.

[0079] The suitable content of the infrared absorbing pigment for achieving comfortable heat generation while satisfying the predetermined ΔE requirement of the present invention may vary according to the color tone of the infrared absorbent knit/woven/nonwoven fabric. In the case of a knit/woven/nonwoven fabric having a bright warm color tone, for example, a reddish or yellowish color tone, the L^∗ value is relatively large and the change in color tone due to the knit/woven/nonwoven fabric comprising the infrared absorbing pigment tends to be easy to identify visually. Therefore, the content of the infrared absorbing pigment for satisfying the ΔE requirement has an upper limit value. In this case, the content of the infrared absorbing pigment per area may be 0.01 g/m² or greater, 0.03 g/m² or greater, 0.05 g/m² or greater, 0.06 g/m² or greater, 0.08 g/m² or greater, 0.10 g/m² or greater, or 0.12 g/m² or greater in order to achieve comfortable heat generation, and may be 0.50 g/m² or less, 0.40 g/m² or less, 0.30 g/m² or less, 0.25 g/m² or less, or 0.20 g/m² or less in order to ensure that the ΔE requirement is fulfilled.

[0080] When the color tone is particularly bright, for example, the L^∗ value is greater than 80 or greater than 90, the content of the infrared absorbing pigment per area may be 0.30 g/m² or less, 0.25 g/m² or less, 0.20 g/m² or less, 0.15 g/m² or less, 0.12 g/m² or less, or 0.10 g/m² or less, from the viewpoint of making the visual identifiability of the change in color tone difficult.

[0081] In the case of knit/woven/nonwoven fabric having a dark cool color tone, for example, a bluish color tone, the L^∗ value is relatively small, and the change in color tone due to the knit/woven/nonwoven fabric comprising the infrared absorbing pigment tends to be difficult to identify visually. Therefore, even when a relatively large amount of the infrared absorbing pigment is contained, the ΔE requirement tends to be easy to satisfy. In this case, the content of the infrared absorbing pigment per area may be 0.05 g/m² or greater, 0.06 g/m² or greater, 0.08 g/m² or greater, 0.10 g/m² or greater, or 0.12 g/m² or greater in order to achieve comfortable heat generation, and may be 0.50 g/m² or less, 0.48 g/m² or less, 0.46 g/m² or less, 0.44 g/m² or less, 0.42 g/m² or less, or 0.40 g/m² or less in order to ensure that the ΔE requirement is fulfilled.

<Configuration of infrared absorbent knit/woven/nonwoven fabric>

[0082] The infrared absorbent knit/woven/nonwoven fabric may be composed of only the infrared absorbent fiber comprising the infrared absorbing pigment, or may be composed of the infrared absorbent fiber comprising the infrared absorbing pigment and a fiber free of any infrared absorbing pigment. The fiber free of any infrared absorbing pigment may be a fiber configured such that the infrared absorbing pigment is removed from the infrared absorbent fiber, or may be a fiber consisting of a different material therefrom.

[0083] It is preferable that a fiber configured such that the infrared absorbing pigment is removed from the infrared absorbent fiber be used as the fiber free of any infrared absorbing pigment, in order to achieve the goal of the present invention to provide preferable designability when applied to garment articles.

[0084] It is preferable that the infrared absorbent knit/woven/nonwoven fabric of the present invention be

composed of only the infrared absorbent fiber comprising the infrared absorbing pigment, or

composed of the infrared absorbent fiber comprising the infrared absorbing pigment and a fiber configured such that the infrared absorbing pigment is removed from the infrared absorbent fiber.

[0085] It is satisfactory if the infrared absorbent knit/woven/nonwoven fabric of the present invention, as a whole knit/woven/nonwoven fabric, satisfies both of the predetermined L^∗ and ΔE requirements of the present invention. The fiber constituting the infrared absorbent knit/woven/nonwoven fabric may satisfy both of the predetermined L^∗ and ΔE requirements of the present invention, or may not satisfy at least one of these requirements.

[0086] The infrared absorbent knit/woven/nonwoven fabric of the present invention, composed of the above fiber, may include

woven fabrics such as plain weave, satin weave, and twill weave;

knit fabrics (knit) such as chain stitch, single crochet stitch, ridge stitch, double crochet stitch, half-double crochet stitch, slip stitch, and tricot; and

nonwoven fabrics produced by appropriate means such as fleece forming methods (for example, dry-laid method, wet-laid method, spun-bonding method, and melt-blowing method) and fleece bonding methods (for example, thermal bonding method, chemical bonding method, needle-punching method, spunlace method, stitch-bonding method, and steam jet method).

<Method for producing infrared absorbent knit/woven fabric>

[0087] The infrared absorbent knit/woven fabric of the present invention may be produced by a known appropriate method or an appropriate modification thereof by a person skilled in the art.

[0088] The infrared absorbent knit/woven fabric of the present invention may be produced by a method such as:

(1) a method of obtaining a knit fabric by knitting the infrared absorbent fiber;

(2) a method of obtaining a woven fabric by weaving the infrared absorbent fiber or the infrared absorbent fiber with a fiber free of any infrared absorbing pigment;

(3) a method of obtaining a nonwoven fabric by an appropriate means, such as fleece forming method or fleece bonding method, using the infrared absorbent fiber or the infrared absorbent fiber and a fiber free of any infrared absorbing pigment; or

(4) a method of applying a coating liquid containing the infrared absorbing pigment to the knit/woven/nonwoven fabric free of any infrared absorbing pigment.

[0089] The coating liquid used in the method (4) may contain, for example, the infrared absorbing pigment and an appropriate solvent, and if necessary, may further contain a binder polymer to improve the adhesion between the infrared absorbing pigment and the knit/woven/nonwoven fabric.

[0090] The infrared absorbent knit/woven/nonwoven fabric of the present invention may comprise a coloring agent such as an appropriate pigment or dye in order to express a predetermined color tone. The coloring agent may be applied at any point of the production process of the infrared absorbent knit/woven/nonwoven fabric. Particularly, the coloring agent may be contained in the coating liquid in the method (3) using a coating liquid.

«Infrared absorbent clothing»

[0091] The present invention further provides infrared absorbent clothing.

[0092] The infrared absorbent clothing of the present invention may include an infrared absorbent knit/woven/nonwoven fabric composed of the infrared absorbent fiber of the present invention and the infrared absorbent knit/woven/nonwoven fabric of the present invention.

[0093] The infrared absorbent clothing of the present invention may be composed of only the infrared absorbent knit/woven/nonwoven fabric as described above, and may be composed of the infrared absorbent knit/woven/nonwoven fabric and a knit/woven/nonwoven fabric free of any infrared absorbing pigment.

[0094] The knit/woven/nonwoven fabric free of any infrared absorbing pigment may be configured such that the infrared absorbing pigment is removed from the infrared absorbent knit/woven/nonwoven fabric, and may consist of a different material therefrom.

[0095] It is preferable that a knit/woven/nonwoven fabric configured such that the infrared absorbing pigment is removed from the infrared absorbent knit/woven/nonwoven fabric be used as the knit/woven/nonwoven fabric free of any infrared absorbing pigment, in order to achieve the goal of the present invention to provide preferable designability.

[0096] It is preferable that the infrared absorbent garment of the present invention be

composed of only the infrared absorbent knit/woven/nonwoven fabric comprising the infrared absorbing pigment, or

composed of the infrared absorbent knit/woven/nonwoven fabric comprising the infrared absorbing pigment and a knit/woven/nonwoven fabric configured such that the infrared absorbing pigment is removed from the infrared absorbent knit/woven/nonwoven fabric.

[0097] The infrared absorbent garment of the present invention, using the knit/woven fabric as described above, may be produced by a known method.

[EXAMPLES]

1. Infrared absorbent knit/woven fabric

[0098] In the following Examples and Comparative Examples, the following raw materials were used for sample preparation.

<Infrared absorbing pigment>

(Cesium tungsten oxide)

[0099] "YMS-01A-2", a dispersion liquid containing 25% by weight of Cs_0.33WO₃ and propylene glycol monomethyl ether acetate as a solvent, manufactured by Sumitomo Metal Mining Co., Ltd.

[0100] Hereinafter, the above infrared absorbing pigment Cs_0.33WO₃ is referred to as "CsWO", and the dispersion liquid containing the CsWO and a solvent is referred to as "CsWO dispersion liquid".

(Antimony-doped tin oxide)

[0101] "ATO", 100% by weight of solid content, manufactured by Ishihara Sangyo Kaisha, Ltd.

(Carbon black)

[0102] Furnace black "R400R", 100% by weight of solid content, manufactured by CABOT Corporation

<Binder polymer>

[0103] Urethane-based resin solution "Resamine ME-44ELPNS", 30% by weight of solid content, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.

<Color ink>

[0104] Red: "MRJ RX02 510 American Red", 37% by weight of solid content, manufactured by Seiko Advance Ltd.

[0105] Yellow: "MRJ RX02 NC200 Primrose Yellow", 37% by weight of solid content, manufactured by Seiko Advance Ltd.

[0106] Blue: "MRJ RX02 440 Blue", 37% by weight of solid content, manufactured by Seiko Advance Ltd.

[0107] White: "MRJ RX02 120 White", 64% by weight of solid content, manufactured by Seiko Advance Ltd.

<<Comparative Example r1>>

(1) Preparation of ink

[0108] 10.0 parts by weight of a red ink (equivalent to 3.70 parts by weight of solid content), 54.0 parts by weight of a urethane-based resin solution (equivalent to 16.20 parts by weight of solid content), and 36.0 parts by weight of methyl ethyl ketone (MEK) were blended to prepare 100 parts by weight of a red base ink containing the red ink in an amount of 10% by weight (wet/wet) and solid content in an amount of 19.9% by weight.

(2) Application

[0109] The ink obtained above was applied to a 100% polyester white fabric (woven fabric having a thickness of 334 µm, L^∗ of 93.6, a^∗ of 1.9, and b^∗ of -8.7) using a Baker applicator under the conditions of a wet film thickness of 200 µm and a coating speed of 5.2 m/min. The ink and the fabric were then allowed to stand at 100 °C for 1 min to remove the solvent to prepare a reference woven fabric sample.

(3) Evaluation

(3-1) Evaluation of photo-exothermic property

[0110] A woven fabric sample cut to a square of 7 cm × 7 cm was irradiated with light from an EYE lamp for lighting (model name "PRF250", rated voltage at 100 V, rated power consumption at 250 W, color temperature at 3,200 K, diffused type) manufactured by Iwasaki Electric Co., Ltd. installed at a position 30 cm away therefrom. The temperatures of the rear surface of the woven fabric (the temperature of the surface opposite to the surface of the side irradiated with light) before irradiation with light (after 0 min) and 5 min after irradiation with light were measured, and from the difference therebetween, the photo-exothermic property of the woven fabric sample was calculated.

[0111] The values of photo-exothermic property of the woven fabric sample thus obtained were used as the reference for calculating the photo-exothermic effect of the infrared absorbing pigments in Examples R1 and R2 and Comparative Example r2.

(3-2) Evaluation of color tone

[0112] L^∗, a^∗, and b^∗ in the CIE 1976 color space were measured for the woven fabric sample obtained above using a spectrophotometer, model name "SpectroEye", manufactured by X-Rite, Inc. The measurement was carried out with white backing paper (L^∗ = 94.84, a^∗ = 0.03, b^∗ = 0.44, and thickness of 0.24 mm) in a three-sheet stack laid under the woven fabric sample.

[0113] The values of L^∗, a^∗, and b^∗ of the woven fabric sample thus obtained were used as the reference for calculating the color difference ΔE from Examples R1 and R2 and Comparative Example r2.

[0114] Further, the woven fabric sample thus obtained was used as the reference for the functional evaluation of color difference in Examples R1 and R2 and Comparative Example r2.

<<Example R1>>

(1) Preparation of ink

[0115] 0.12 parts by weight of the CsWO dispersion liquid (equivalent to 0.030 parts by weight of CsWO) were added to 100 parts by weight of a red base ink prepared in the same manner as in Comparative Example r1 to prepare an infrared absorbent red ink containing the red ink in an amount of 10% by weight (wet/wet) and CsWO in an amount of 0.15% by weight per ink solid content.

(2) Application

[0116] Except that the infrared absorbent red ink obtained above was used, the ink was applied to a 100% polyester white fabric (woven fabric) in the same manner as in Comparative Example r1 to produce a woven fabric sample. The dry weight of the applied ink was determined from the difference in weight between the fabric before application and the woven fabric sample after application. From the amount of the infrared absorbing pigment contained therein and the area of the application surface, the content of the infrared absorbing pigment per unit area of the woven fabric sample was calculated.

(3) Evaluation

(3-1) Evaluation of photo-exothermic effect

[0117] Using the woven fabric sample obtained in Example R1, the photo-exothermic property and the color tone were evaluated in the same manner as in Comparative Example r1. The value of the photo-exothermic property of the woven fabric sample of Comparative Example r1 was subtracted from the value of the photo-exothermic property of the woven fabric sample to calculate the photo-exothermic effect of the infrared absorbing pigment in the woven fabric sample of Example R1.

(3-2) Evaluation of color difference ΔE

[0118] From the values of L^∗, a^∗, and b^∗ of the woven fabric sample and the values of L^∗, a^∗, and b^∗ of the reference woven fabric sample of Comparative Example r1, the color difference ΔE of the woven fabric sample of Example R1 from the reference of Comparative Example r1 was calculated.

(3-3) Functional evaluation of color difference

[0119] The woven fabric sample thus obtained in the Example and the reference woven fabric sample obtained in Comparative Example r1 were placed side by side on a three-sheet stack of white backing paper (L^∗ = 94.84, a^∗ = 0.03, b^∗ = 0.44, and thickness of 0.24 mm). Whether the difference in color tone between the two samples could be visually identify when irradiated with a daylight fluorescent lamp was investigated. The test was carried out by six testers and evaluated according to the following criteria.

A: When there were no testers (0 persons) who could visually identify the difference in color tone between the two samples (satisfactory)

B: When there were 1 or 2 testers who could visually identify the difference in color tone between the two samples (pass)

C: When there were 3 or more testers who could visually identify the difference in color tone between the two samples (fail)

<<Example R2 and Comparative Example r2>>

[0120] Except that each of the amounts of the CsWO dispersion liquid added to 100 parts by weight of the infrared absorbent red base ink was set as indicated in Table 1, each infrared absorbent red ink was prepared in the same manner as in Example R1, and then applied on fabric and evaluated.

<<Comparative Example r3>>

[0121] Except that each of the amounts of the urethane resin solution, the red ink, and MEK used was set as indicated in Table 1, a red base ink containing the red ink in an amount of 30% by weight (wet/wet) and solid content in an amount of 21.6% by weight was prepared, and then applied on fabric and evaluated.

[0122] The photo-exothermic property and the values of L^∗, a^∗, and b^∗ of the woven fabric sample thus obtained were used as the reference for calculating the photo-exothermic effect and the color difference ΔE of the infrared absorbing pigments in Examples R3 and R4 and Comparative Example r4.

[0123] Further, the woven fabric sample thus obtained was used as the reference for the functional evaluation of color difference in Examples R3 and R4 and Comparative Example r4.

<<Example R3>>

(1) Preparation of ink

[0124] 0.13 parts by weight of the CsWO dispersion liquid (equivalent to 0.03 parts by weight of CsWO) were added to 100 parts by weight of a red base ink prepared in the same manner as in Comparative Example r3 to prepare an infrared absorbent red ink containing a red ink in an amount of 30% by weight (wet/wet) and CsWO in an amount of 0.15% by weight per ink solid content. The infrared absorbent red ink was applied on fabric and evaluated.

<<Example R4 and Comparative Example r4>>

[0125] 100 parts by weight of a red base ink prepared in the same manner as in Comparative Example r3 were used as the red base ink. Except that each of the amounts of the CsWO dispersion liquid added to 100 parts by weight of the red base ink was set as indicated in Table 1, each of the red base inks was prepared in the same manner as in Example R3, and then applied to fabric and evaluated.

[0126] The above results are shown in Table 2.

[Table 1]

[0127] 

Table 1. Blending of infrared absorbent red ink

	Red ink		Urethane resin solution		MEK	CsWO dispersion liquid		CsWO amount per ink solid content (wt%)
	Amount used (parts by weight)	Solid content (parts by weight)	Amount used (parts by weight)	Solid content (parts by weight)	Amount used (parts by weight)	Amount used (parts by weight)	Solid content (parts by weight)
Comparative Example r1	10.0	3.70	54.0	16.20	36.0	0.00	0.000	0.00
Example R1	10.0	3.70	54.0	16.20	36.0	0.12	0.030	0.15
Example R2	10.0	3.70	54.0	16.20	36.0	0.24	0.060	0.30
Comparative Example r2	10.0	3.70	54.0	16.20	36.0	0.48	0.120	0.60
Comparative Example r3	30.0	11.10	35.0	10.50	35.0	0.00	0.000	0.00
Example R3	30.0	11.10	35.0	10.50	35.0	0.13	0.033	0.15
Example R4	30.0	11.10	35.0	10.50	35.0	0.26	0.065	0.30
Comparative Example r4	30.0	11.10	35.0	10.50	35.0	0.51	0.128	0.59

[Table 2]

[0128] 

Table 2. Evaluation of woven fabric having infrared absorbent red ink applied thereon

	CsWO amount per unit area of woven fabric sample	Photo-exothermic property				Color tone
		Before irradiatio n with light	After 5 min (°C)	Temperat ure elevation (°C)	Differenc e from reference (°C)	L∗	a∗	b∗	Color difference ΔE from reference	Functional evaluation
Comparative Example r1	0.00	23.9	36.9	13.0	-	44.2	63.9	25.9	-	-
Example R1	0.07	23.9	42.4	18.5	5.5	41.0	60.6	26.8	4.6	A
Example R2	0.10	23.6	44.6	21.0	8.0	42.6	58.4	21.5	7.1	A
Comparative Example r2	0.25	23.6	47.9	24.3	11.3	38.6	53.8	22.1	12.1	C
Comparative Example r3	0.00	24.0	36.6	12.6	-	39.7	61.3	27.4	-	-
Example R3	0.07	23.8	43.5	19.7	7.1	37.5	57.8	27.4	4.1	A
Example R4	0.16	24.2	47.3	23.1	10.5	36.1	53.5	26.3	8.7	B
Comparative Example r4	0.34	23.9	49.6	25.7	13.1	34.4	49.0	23.6	13.9	C

<<Comparative Example y1, Examples Y1 and Y2, Comparative Examples y2 and y3, Examples Y3 and Y4, and Comparative Example y4>>

[0129] Except that yellow ink was used in place of red ink in the same amounts, yellow base inks (Comparative Examples y1 and y3) and infrared absorbent yellow inks (Examples Y1 to Y4 and Comparative Examples y2 and y4) were prepared in the same manner as in Comparative Example r1, Examples R1 and R2, Comparative Examples r2 and r3, and Examples R3 and R4, and then applied on fabric and evaluated.

[0130] The photo-exothermic property and the values of L^∗, a^∗, and b^∗ of the woven fabric sample obtained in Comparative Example y1 were used as the reference for calculating the photo-exothermic effect and the color difference ΔE of the infrared absorbing pigments in Examples Y1 and Y2 and Comparative Example y2. Further, the woven fabric sample obtained in Comparative Example y1 was used as the reference for the functional evaluation of color difference in Examples Y1 and Y2 and Comparative Example y2.

[0131] The photo-exothermic property and the values of L^∗, a^∗, and b^∗ of the woven fabric sample obtained in Comparative Example y3 were used as the reference for calculating the photo-exothermic effect and the color difference ΔE of the infrared absorbing pigments in Examples Y3 and Y4 and Comparative Example y4. Further, the woven fabric sample obtained in Comparative Example y3 was used as the reference for the functional evaluation of color difference in Examples Y3 and Y4 and Comparative Example y4.

[0132] The blending of inks in the above Examples and Comparative Examples are shown in Table 3. Further, the evaluation results of the photo-exothermic property and color tone (L^∗, a^∗, b^∗, and color difference ΔE) thereof are shown in Table 4.

[Table 3]

[0133] 

Table 3. Blending of infrared absorbent yellow ink

	Yellow ink		Urethane resin solution		MEK	CsWO dispersion liquid		CsWO amount per ink solid content (wt%)
	Amount used (parts by weight)	Solid content (parts by weight)	Amount used (parts by weight)	Solid content (parts by weight)	Amount used (parts by weight)	Amount used (parts by weight)	Solid content (parts by weight)
Comparative Example y1	10.0	3.70	54.0	16.20	36.0	0.00	0.000	0.00
Example Y1	10.0	3.70	54.0	16.20	36.0	0.12	0.030	0.15
Example Y2	10.0	3.70	54.0	16.20	36.0	0.24	0.060	0.30
Comparative Example y2	10.0	3.70	54.0	16.20	36.0	0.48	0.120	0.60
Comparative Example y3	30.0	11.10	35.0	10.50	35.0	0.00	0.000	0.00
Example Y3	30.0	11.10	35.0	10.50	35.0	0.13	0.033	0.15
Example Y4	30.0	11.10	35.0	10.50	35.0	0.26	0.065	0.30
Comparative Example y4	30.0	11.10	35.0	10.50	35.0	0.51	0.128	0.59

[Table 4]

[0134] 

Table 4. Evaluation of cloth having infrared absorbent yellow ink applied thereon

	CsWO amount per unit area of cloth sample (g/m2)	Photo-exothermic property				Color tone
		Before irradiation with light (°C)	After 5 min (°C)	Temperat ure elevation (°C)	Differenc e from reference (°C)	L∗	a∗	b∗	Color difference ΔE from reference	Functional evaluation
Comparative Example y1	0.00	23.8	35.5	11.7	-	89.0	-5.3	83.4	-	-
Example Y1	0.06	23.3	38.6	15.3	3.6	87.3	-6.3	81.1	3.1	A
Example Y2	0.13	23.7	40.1	16.4	4.7	85.6	-7.5	78.1	6.7	A
Comparative Example y2	0.26	23.4	44.1	20.7	9.0	82.7	-9.3	73.4	12.5	C
Comparative Example y3	0.00	24.1	36.2	12.1	-	87.9	-0.1	90.1	-	-
Example Y3	0.08	23.9	40.4	16.5	4.4	85.9	-1.6	87.5	3.7	A
Example Y4	0.15	23.8	43.6	19.8	7.7	84.1	-3.1	84.7	7.3	B
Comparative Example y4	0.30	23.5	46.1	22.6	10.5	81.1	-5.4	79.0	14.1	C

«Comparative b1 and Examples B1 to B4>>

[0135] Except that blue ink was used in place of red ink in the same amounts, a blue base ink (Comparative Example b1) and infrared absorbent blue inks (Examples B1 to B4) were prepared in the same manner as in Comparative Example r1, Examples R1 and R2, Comparative Examples r2, and then applied on fabric and evaluated.

[0136] The photo-exothermic property and the values of L^∗, a^∗, and b^∗ of the woven fabric sample obtained in Comparative Example b1 were used as the reference for calculating the photo-exothermic effect and the color difference ΔE of the infrared absorbing pigments in Examples B1 to B4. Further, the woven fabric sample obtained in Comparative Example b1 was used as the reference for the functional evaluation of color difference in Examples B1 to B4.

[0137] The blending of inks in the above Examples and Comparative Example are shown in Table 5. Further, the evaluation results of the photo-exothermic property and color tone (L^∗, a^∗, b^∗, and color difference ΔE) thereof are shown in Table 6.

[Table 5]

[0138] 

Table 5. Blending of infrared absorbent blue ink

	Blue ink		Urethane resin solution		MEK	CsWO dispersion liquid		CsWO amount per ink solid content (wt%)
	Amount used (parts by weight)	Solid content (parts by weight)	Amount used (parts by weight)	Solid content (parts by weight)	Amount used (parts by weight)	Amount used (parts by weight)	Solid content (parts by weight)
Comparative Example b1	10.0	3.70	54.0	16.20	36.0	0.00	0.000	0.00
Example B1	10.0	3.70	54.0	16.20	36.0	0.12	0.030	0.15
Example B2	10.0	3.70	54.0	16.20	36.0	0.24	0.060	0.30
Example B3	10.0	3.70	54.0	16.20	36.0	0.48	0.120	0.60
Example B4	10.0	3.70	54.0	16.20	36.0	1.02	0.255	1.27

[Table 6]

[0139] 

Table 6. Evaluation of cloth having infrared absorbent blue ink applied thereon

	CsWO amount per unit area of cloth sample (g/m2)	Photo-exothermic property				Color tone
		Before irradiation with light (°C)	After 5 min (°C)	Temperatu re elevation (°C)	Difference from reference (°C)	L∗	a∗	b∗	Color difference ΔE from reference	Function al evaluatio n
Comparati Example b1	0.00	23.7	39.7	16.0	-	35.9	-5.5	- 51.4	-	-
Example B1	0.05	23.9	44.5	20.6	4.6	35.3	-5.2	51.5	1.1	A
Example B2	0.10	23.7	46.6	22.9	6.9	34.4	-5.0	50.1	2.0	A
Example B3	0.21	24.0	49.0	25.0	9.0	34.0	-4.7	48.7	3.4	A
Example B4	0.44	23.4	52.1	28.7	12.7	31.4	-3.2	45.5	7.7	A

<<Example R5>>

[0140] 0.24 parts by weight of antimony-doped tin oxide ("ATO", 100% by weight of solid content, manufactured by Ishihara Sangyo Co., Ltd.) as an infrared absorbing pigment were added to 100 parts by weight of a red base ink prepared in the same manner as in Comparative Example r1 to prepare an infrared absorbent red ink having a red ink in an amount of 10% by weight (wet/wet) and the ATO in an amount of 1.19% by weight per ink solid content. Otherwise, the infrared absorbent red ink was applied to fabric and evaluated in the same manner as in Example R1.

<<Comparative Example r5>>

[0141] 0.03 parts by weight of carbon black (CB) (furnace black "R400R", 100% by weight of solid content, manufactured by CABOT Corporation) as an infrared absorbing pigment were added to 100 parts by weight of a red base ink prepared in the same manner as in Comparative Example r1 to prepare an infrared absorbent red ink containing a red ink in an amount of 10% by weight (wet/wet) and the CB in an amount of 0.15% by weight per ink solid content. Otherwise, the infrared absorbent red ink was applied to fabric and evaluated in the same manner as in Example R1.

[0142] In the evaluation of these Examples and Comparative Examples, the woven fabric sample obtained in Comparative Example r1 was used as a reference woven fabric sample of photo-exothermic property, color difference ΔE, and functional evaluation.

[0143] The blending of the inks of the above Examples and Comparative Examples and the blending of Comparative Example r1 are shown together in Table 7. The evaluation results of the photo-exothermic effect and color tone (L^∗, a^∗, b^∗, and color difference ΔE) thereof are shown in Table 8.

[Table 7]

[0144] 

Table 7. Blending of infrared absorbent red ink

	Red ink		Urethane resin solution		MEK	Infrared absorbing pigment		Content of infrared absorbing pigment per ink solid content (wt%)
	Amount used (parts by weight)	Solid content (parts by weight)	Amount used (parts by weight)	Solid content (parts by weight)	Amount used (parts by weight)	Type	Amount used (solid content parts by weight)
Comparative Example r1	10.0	3.70	54.0	16.20	36.0	-	0.000	0.00
Example R5	10.0	3.70	54.0	16.20	36.0	ATO	0.240	1.19
Comparative Example r5	10.0	3.70	54.0	16.20	36.0	CB	0.030	0.15

[Table 8]

[0145] 

Table 8. Evaluation of cloth having infrared absorbent red ink applied thereon

	Infrared absorbing pigment amount per unit area of cloth sample (g/m2)	Photo-exothermic property				Color tone
		Before irradiation with light (°C)	After 5 min (°C)	Temperat ure elevation (°C)	Differenc e from reference (°C)	L∗	a∗	b∗	Color difference ΔE from reference	Function al evaluatio n
Comparativ e Example r1	0.00	23.9	36.9	13.0	-	44.2	63.9	25.9	-	-
Example R5	0.44	23.3	42.9	19.6	6.6	41.7	60.6	25.1	4.2	A
Comparativ e Example r5	0.06	23.4	45.5	22.1	9.1	36.1	44.2	14.7	24.0	C

«Comparative Example p1 to p3 and Examples P1 to P3>>

[0146] Except that the amounts of each color ink, the urethane resin solution, and MEK used were each changed as indicated in Table 9, base inks of each color (Comparative Examples p1 to p3) and infrared absorbent inks of each color (Examples P1 to P3) were prepared, and then applied on fabric and evaluated.

[0147] The samples of Comparative Example p1, Comparative Example p2, and Comparative Example p3 were used as the reference woven fabric sample of photo-exothermic property, color difference ΔE, and functional evaluation in the evaluations thereof for the samples of Example P1, Example P2, and Example P3, respectively. The results thus obtained are shown in Table 10.

[Table 9]

[0148] 

Table 9. Blending of infrared absorbent inks of respective colors

	Yellow ink		Blue ink		Red ink		White ink
	Amount used (parts by weight)	Solid content (parts by weight)	Amount used (parts by weight)	Solid content (parts by weight)	Amount used (parts by weight)	Solid content (parts by weight)	Amount used (parts by weight)	Solid content (parts by weight)
Comparative Example p1	8.48	3.14	-	-	-	-	15.15	9.70
Example P1	8.46	3.13	-	-	-	-	15.17	9.71
Comparative Example p2	6.74	2.49	0.04	0.02	-	-	28.11	17.99
Example P2	6.71	2.48	0.04	0.02	-	-	28.07	17.97
Comparative Example p3	-	-	-	-	0.35	0.13	65.05	41.63
Example P3	-	-	-	-	0.35	0.13	65.05	41.63

	Urethane resin solution		MEK		CsWO dispersion liquid		CsWO amount per ink solid content (wt%)
	Amount used (parts by weight)	Solid content (parts by weight)	Amount used (parts by weight)		Amount used (parts by weight)	Solid content (parts by weight)
Comparative Example p1	45.82	13.75	30.55		0.00	0.00	0.00
Example P1	45.70	13.71	30.47		0.20	0.05	0.19
Comparative Example p2	36.63	10.99	28.47		0.00	0.00	0.00
Example P2	36.49	10.95	28.36		0.32	0.08	0.25
Comparative Example p3	1.89	0.57	32.72		0.00	0.00	0.00
Example P3	1.87	0.56	32.70		0.03	0.01	0.02

[Table 10]

[0149] 

Table 10. Evaluation of cloth having infrared absorbent inks of respective colors applied thereon

	CsWO amount per unit area of cloth sample (g/m2)	Photo-exothermic property				Color tone
		Before irradiation with light (°C)	After 5 min (°C)	Temperatu re elevation (°C)	Difference from reference (°C)	L∗	a∗	b∗	Color difference ΔE from reference	Functional evaluation
Comparative Example p1	0.00	25.0	37.4	12.4	-	95.5	-5.7	50.2	-	-
Example P1	0.14	24.9	41.6	16.7	4.3	93.5	-7.5	49.2	2.9	A
Comparative Example p2	0.00	24.5	36.2	11.7	-	92.1	- 11.6	31.8	-	-
Example P2	0.25	24.4	42.3	17.9	6.2	90.7	- 11.6	29.3	2.8	A
Comparative Example p3	0.00	24.5	39.4	14.9	-	90.0	10.6	-0.4	-	-
Example P3	0.03	24.3	41.1	16.8	1.9	90.1	10.9	-0.5	0.3	A

2. Infrared absorbent fiber

[0150] In the following Examples and Comparative Examples, tricots or woven fabrics produced using an infrared absorbent fiber comprising an infrared absorbing pigment were tested. Cesium tungsten oxide was used as the infrared absorbing pigment, the content thereof in the fiber was set at two levels of 0.11% by weight and 0.52% by weight, and polyethylene terephthalate (PET)-based infrared absorbent fibers were produced thereby and tested.

[0151] In the following Examples and Comparative Examples, the following raw materials were used for sample preparation.

<Infrared absorbing pigment>

(Cesium tungsten oxide)

[0152] "YMDS-874", a dispersion powder containing 23% by weight of Cs_0.33WO₃ and a dispersant, manufactured by Sumitomo Metal Mining Co., Ltd.

[0153] Hereinafter, the above infrared absorbing pigment Cs_0.33WO₃ is referred to as "CsWO", and the dispersion powder containing the CsWO and a dispersant is referred to as "CsWO dispersion powder".

<Base resin>

[0154] "Bell-PET IP121B", a copolymer-type polyethylene terephthalate comprising isophthalic acid as the third component, intrinsic viscosity = 0.62, manufactured by Bell Polyester Products, Inc.

<Preparation of CsWO masterbatch>

[0155] 95 parts by weight of a base resin and 5 parts by weight of CsWO dispersion powder (equivalent to 1.15 parts by weight of CsWO) were kneaded in a twin-screw extruder to obtain a CsWO masterbatch comprising 1.15% by weight of CsWO.

<<Comparative Example t1>>

(1) Spinning

[0156] Homo-PET as a spinning raw material was spun for 1 h using a multifilament melt-spinning apparatus under the conditions of a spinning temperature of 290 °C, an extrusion rate of 4 kg/h, and a take-up rate of 1,500 m/min to obtain a 50-denier 24-filament multifilament fiber.

(2) Fabric production

[0157] A 32-gauge tricot fabric having a basis weight of 240 g/m² was produced by a knitting machine using 80% by weight of the above multifilament fiber and 20% by weight of a polyurethane fiber.

(3) Evaluation

(3-1) Evaluation of photo-exothermic property

[0158] A tricot fabric sample cut to a square of 7 cm × 7 cm was irradiated with light from an EYE lamp for lighting (model name "PRF250", rated voltage at 100 V, rated power consumption at 250 W, color temperature at 3,200 K, diffused type) manufactured by Iwasaki Electric Co., Ltd. installed at a position 30 cm away therefrom. The temperatures of the rear surface of the tricot fabric before irradiation with light (after 0 min) and 5 min after irradiation with light were measured, and from the difference therebetween, the photo-exothermic property of the tricot fabric sample was calculated.

[0159] The values of photo-exothermic property of the tricot fabric sample thus obtained was used as the reference for calculating the photo-exothermic effect of the infrared absorbing pigments in Example T1 and Comparative Example t2.

(3-2) Evaluation of color tone

[0160] L^∗, a^∗, and b^∗ in the CIE 1976 color space were measured for the tricot fabric sample obtained above using a spectrophotometer, model name "SpectroEye", manufactured by X-Rite, Inc. The measurement was carried out with white backing paper (L^∗ = 94.84, a^∗ = 0.03, b^∗ = 0.44, and thickness of 0.24 mm) in a three-sheet stack laid under the woven fabric sample.

[0161] The values of L^∗, a^∗, and b^∗ of the tricot fabric sample thus obtained were used as the reference for calculating the color difference ΔE from Example T1 and Comparative Example t2.

<<Example T1>>

(1) Spinning

[0162] Except that 9.57 parts by weight of the CsWO masterbatch and 90.43 parts by weight of homo-PET as spinning raw material were used, an infrared absorbent multifilament fiber containing 0.11% by weight of CsWO was obtained in the same manner as in Comparative Example t1.

(2) Fabric production

[0163] Except that 80% by weight of the above infrared absorbent multifilament fiber and 20% by weight of a polyurethane fiber were used, an infrared absorbent tricot fabric was produced in the same manner as in Comparative Example t1. The CsWO content of the infrared absorbent tricot fabric was 0.19 g/m².

(3) Evaluation

[0164] The infrared absorbent tricot fabric thus obtained was evaluated in the same manner as in Comparative Example t1.

<<Comparative Example t2>>

[0165] Except that 45.25 parts by weight of the CsWO masterbatch and 54.75 parts by weight of homo-PET were used as spinning raw material, an infrared absorbent multifilament fiber containing 0.52% by weight of CsWO was obtained in the same manner as in Comparative Example t1. Using the infrared absorbent multifilament fiber thus obtained, an infrared absorbent tricot fabric was produced in the same manner as in Example T1 and then evaluated.

[0166] The evaluation results of the photo-exothermic effect and color tone (L^∗, a^∗, b^∗, and color difference ΔE) of the Example and Comparative Examples above are shown in Table 11.

[Table 11]

[0167] 

Table 11. Evaluation of infrared absorbent tricot fabric

	concentration in fiber (% by weight)	CsWO amount per . unit area of tricot sample (g/m2)	Photo-exothermic property				Color tone
			Before irradiation with light (°C)	After 5 min (°C)	Temperatu re elevation (°C)	Difference from reference (°C)	L∗	a∗	b∗	Color difference ΔE from reference
Comparati ve Example t1	0.00	0.00	22.6	36.0	13.4	-	91.0	-0.3	2.8	-
Example T1	0.11	0.19	22.6	47.4	24.8	11.4	85.0	-3.3	-2.7	8.6
Comparati ve Example t2	0.52	1.14	22.5	51.9	29.4	16.0	69.2	-7.0	-8.0	25.2

<<Comparative Example c1>>

(1) Spinning

[0168] Homo-PET as a spinning raw material was spun for 1 h using a multifilament melt-spinning apparatus under the conditions of a spinning temperature of 290 °C, an extrusion rate of 4 kg/h, and a take-up rate of 1,500 m/min to obtain a 75-denier 24-filament multifilament fiber. Two of the multifilament fibers were twisted together to obtain a two-ply yarn equivalent to 150 denier.

(2) Woven fabric production

[0169] The obtained two-ply yarn as the weft and a polyester/wool blended yarn (250 denier) having a weight ratio of 50:50 as the warp were weaved in a 3/1 twill using a Schönherr weaving machine at a weight ratio of 41:59 as the usage ratio of weft: warp to obtain a woven fabric having a basis weight of 170 g/m².

(3) Evaluation

[0170] Since the woven fabric thus obtained was a woven fabric in a 3/1 twill weave, the warp surface where the polyester/wool blended yarn, which was the warp, was mainly exposed and the weft surface where the two-ply yarn, which was the weft, was mainly exposed form the front and rear sides. Therefore, the exothermic property and the color tone of the woven fabric sample were evaluated for both the warp surface and the weft surface.

(3-1) Evaluation of photo-exothermic property

[0171] A woven fabric sample cut to a square of 7 cm × 7 cm was irradiated with light from an EYE lamp for lighting (model name "PRF250", rated voltage at 100 V, rated power consumption at 250 W, color temperature at 3,200 K, diffused type) manufactured by Iwasaki Electric Co., Ltd. installed at a position 30 cm away therefrom. The temperatures of the rear surface of the woven fabric before irradiation with light (after 0 min) and 5 min after irradiation with light were measured, and from the difference therebetween, the photo-exothermic property of the woven fabric sample was calculated.

[0172] The obtained value of the photo-exothermic property of the woven fabric sample was used as the reference for calculating the photo-exothermic effect on both the warp surface and the weft surface of the infrared absorbent woven fabric of each of Example C1 and Comparative Example c2.

(3-2) Evaluation of color tone

[0173] L^∗, a^∗, and b^∗ in the CIE 1976 color space were measured for the woven fabric sample obtained above using a spectrophotometer, model name "SpectroEye", manufactured by X-Rite, Inc. The measurement was carried out with white backing paper (L^∗ = 94.84, a^∗ = 0.03, b^∗ = 0.44, and thickness of 0.24 mm) in a three-sheet stack laid under the woven fabric sample.

[0174] The values of L^∗, a^∗, and b^∗ of the woven fabric sample thus obtained were used as the reference for calculating the color difference ΔE on the warp and weft surfaces of each of Example C1 and Comparative Example c2.

<<Example C1>>

(1) Spinning

[0175] Except that 9.57 parts by weight of the CsWO masterbatch and 90.43 parts by weight of homo-PET as spinning raw material were used, a 75-denier 24-filament infrared absorbent multifilament fiber containing 0.11% by weight of CsWO was obtained in the same manner as in Comparative Example c1. Two of the infrared absorbent multifilament fibers were twisted together to obtain a two-ply yarn equivalent to 150 denier.

(2) Woven fabric production

[0176] Except that the infrared absorbent two-ply yarn obtained above was used as the weft, an infrared absorbent woven fabric having a basis weight of 170 g/m² was obtained in the same manner as in Comparative Example c1. The CsWO content of the infrared absorbent woven fabric was 0.08 g/m².

(3) Evaluation

[0177] The infrared absorbent woven fabric thus obtain was evaluated in the same manner as Comparative Example c1.

<<Comparative Example c2>>

[0178] Except that 45.25 parts by weight of the CsWO masterbatch and 54.75 parts by weight of homo-PET as spinning raw material were used, an infrared absorbent multifilament fiber containing 0.52% by weight of CsWO was obtained in the same manner as in Comparative Example c1. Except that the infrared absorbent multifilament fiber thus obtained was used, an infrared absorbent two-ply yarn was produced in the same manner as in Example C1, which was then used to obtain an infrared absorbent woven fabric having a basis weight of 170 g/m². The CsWO content of the infrared absorbent woven fabric was 0.35 g/m².

[0179] The infrared absorbent woven fabric was evaluated in the same manner as Comparative Example c1.

[0180] The evaluation results of the photo-exothermic effect and color tone (L^∗, a^∗, b^∗, and color difference ΔE) of the Example and Comparative Examples above are shown in Table 12.

[Table 12]

[0181] 

Table 12. Evaluation of infrared absorbent cloth

	CsWO concentration in fiber (% by weight)	CsWO amount per unit area of woven fabric sample (g/m2)	Surface evaluate d	Photo-exothermic property				Color tone
				Before irradiation with light (°C)	After 5 min (°C)	Temperat ure elevation (°C)	Differenc e from reference (°C)	L∗	a∗	b∗	Color difference ΔE from reference
Comparati ve Example c1	0.00	0.00	warp	27.2	37.4	10.2	-	94.1	-0.3	2.3	-
			weft	26.8	36.9	10.1	-	94.1	-0.2	2.3	-
Example C1	0.11	0.08	warp	25.9	42.4	16.5	6.3	91.1	-1.0	2.5	3.1
			weft	27.4	44.3	16.9	6.8	90.2	-1.1	2.2	4.0
Comparati ve Example c2	0.35	0.52	warp	26.2	46.2	20.0	9.8	87.0	-3.0	-0.5	8.1
			weft	25.9	50.0	24.1	14.0	85.0	-4.1	-1.3	10.5

Claims

1. An infrared absorbent fiber, knit/woven fabric, or nonwoven fabric comprising an infrared absorbing pigment,

wherein L^∗ in CIE 1976 color space is 30 or greater, and

a color difference ΔE in the CIE 1976 color space between the infrared absorbent fiber, knit/woven fabric, or nonwoven fabric and the infrared absorbent fiber, knit/woven fabric, or nonwoven fabric not comprising the infrared absorbing pigment is 10 or less.

2. The infrared absorbent fiber, knit/woven fabric, or nonwoven fabric according to claim 1, wherein the L^∗ in the CIE 1976 color space is greater than 90, and at least one of (i) to (iv) below is satisfied:

(i) a^∗ in the CIE 1976 color space is -10 or less,

(ii) a^∗ in the CIE 1976 color space is 10 or greater,

(iii) b^∗ in the CIE 1976 color space is -10 or less, and

(iv) b^∗ in the CIE 1976 color space is 10 or greater.

3. The infrared absorbent fiber, knit/woven fabric, or nonwoven fabric according to claim 1, wherein the L^∗ in the CIE 1976 color space is 90 or less.

4. The infrared absorbent fiber, knit/woven fabric, or nonwoven fabric according to any one of claims 1 to 3,

wherein the infrared absorbent fiber has a content of the infrared absorbing pigment of 0.01% by mass or greater and 0.50% by mass or less based on a total mass of the infrared absorbent fiber for, and

the infrared absorbent knit/woven fabric has a content of the infrared absorbing pigment of 0.05 g/m² or greater and 0.5 g/m² or less per area of the infrared absorbent knit/woven fabric.

5. The infrared absorbent fiber, knit/woven fabric, or nonwoven fabric according to any one of claims 1 to 4,

wherein the infrared absorbing pigment comprises at least one or more selected from the group consisting of

a composite tungsten oxide, represented by

        general formula M_xW_yO_z     (1)

wherein M is one or more elements selected from the group consisting of H, He, alkali metals, alkaline earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; W is tungsten; O is oxygen; x, y, and z are each a positive number; 0 < x/y ≤ 1; and 2.2 ≤ z/y ≤ 3.0, and

a tungsten oxide having a Magnéli phase, represented by

        general formula W_yO_z     (2)

wherein W is tungsten; O is oxygen; y and z are each a positive number; and 2.45 ≤ z/y ≤ 2.999.

6. The infrared absorbent fiber according to any one of claims 1 to 5.

7. An infrared absorbent knit/woven fabric or nonwoven fabric, composed of the infrared absorbent fiber according to claim 6.

8. An infrared absorbent knit/woven fabric or nonwoven fabric, composed of the infrared absorbent fiber according to claim 6 and a fiber free of any infrared absorbing pigment,
wherein the fiber free of any infrared absorbing pigment is configured such that the infrared absorbing pigment is removed from the infrared absorbent fiber.

9. The infrared absorbent knit/woven fabric or nonwoven fabric according to any one of claims 1 to 5.

10. The infrared absorbent knit/woven fabric or nonwoven fabric according to claim 9, composed of the infrared absorbent fiber comprising the infrared absorbing pigment.

11. The infrared absorbent knit/woven fabric or nonwoven fabric according to claim 9, composed of the infrared absorbent fiber comprising the infrared absorbing pigment and a fiber free of any infrared absorbing pigment,
wherein the fiber free of any infrared absorbing pigment is configured such that the infrared absorbing pigment is removed from the infrared absorbent fiber.

12. An infrared absorbent clothing, composed of the infrared absorbent knit/woven fabric or nonwoven fabric according to any one of claims 7 to 11.

13. An infrared absorbent clothing, composed of the infrared absorbent knit/woven fabric or nonwoven fabric according to any one of claims 7 to 11 and a knit/woven fabric or nonwoven fabric free of any infrared absorbing pigment,
wherein the knit/woven fabric or nonwoven fabric free of any infrared absorbing pigment is configured such that the infrared absorbing pigment is removed from the infrared absorbent knit/woven fabric or nonwoven fabric.