Knitted fabric and shoe upper material

Abstract

To provide a fabric allowing feet to be easily warmed and applying an excellent hot feeling effect when used as an upper material for shoes.SOLUTION: The fabric used for an upper material for shoes comprises a light absorption thermal conversion fiber containing 1-20 pts.mass % of a light absorption thermal conversion particle, and in one surface of the fabric a rate of an area of the light absorption thermal conversion fiber occupied in the surface is equal to or greater than 30% and the one surface is arranged and used outside of the upper material for shoes.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a knitted fabric that, when used as a shoe upper material, easily warms the foot and provides an excellent warming effect (the effect of feeling warmth). The present invention also relates to a shoe upper material using the knitted fabric. [Background technology]

[0002] Conventionally, efforts have been made to improve shoe upper materials in terms of weight reduction, comfort, durability, etc. For example, Patent Document 1 discloses that in an upper material for sports shoes formed of a three-dimensional structure fabric in which the front and back ground structures are connected by connecting threads, by using specific hollow fibers and setting the density and thickness of the fabric within specific ranges, wear resistance, weight reduction, reduction in the feeling of pressure on the foot, reduction in the feeling of stuffiness in the shoe, etc. are achieved.

[0003] In recent years, the performance requirements for shoes have become more diverse, and there is a demand for the development of shoe upper materials that meet various needs. For example, shoes used in cold environments (cold regions, winter, etc.) are required to have a warming effect that makes it easy to warm the feet when worn. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-77558 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a knitted fabric that, when used as a shoe upper material, easily warms the foot and provides an excellent warming effect. Another object of the present invention is to provide a shoe upper material using the knitted fabric. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above problems and have found that a knitted fabric containing light-absorbing heat-converting fibers containing 1-20% by mass of light-absorbing heat-converting particles as a constituent fiber, and having an area ratio of the light-absorbing heat-converting fibers on one side of the knitted fabric to the total area of ​​the surface of the knitted fabric of 30% or more, can easily warm the feet and provide an excellent warming effect when used as an upper material for shoes.The present invention was completed based on this knowledge and through further research.

[0007] That is, the present invention provides the following aspects. Item 1. A knitted fabric used as a shoe upper material, The light-absorbing and heat-converting fiber contains 1 to 20 mass % of light-absorbing and heat-converting particles, On one side of the knitted fabric, the ratio of the area of ​​the light-absorbing heat converting fiber to the total area of ​​the surface is 30% or more, The knitted fabric is used with the one surface being placed on the outside of a shoe upper material. Item 2. The knitted fabric according to Item 1, wherein the light absorption / heat converting particles are at least one selected from the group consisting of carbon black, zirconium carbide, silicon carbide, boron carbide, tin oxide, aluminum oxide, silicon dioxide, mica, and talc. Item 3. The knitted fabric according to item 1 or 2, wherein the light absorbing and heat converting particles have a core-sheath structure, and the light absorbing and heat converting particles are contained only in the core. Item 4. The knitted fabric according to item 3, wherein the mass ratio of the core to the sheath is 50 / 50 to 85 / 15 (core / sheath mass ratio). Item 5. The knitted fabric according to item 3 or 4, wherein the constituent resin of the core is polyester, and the constituent resin of the sheath is polyester. Item 6. The knitted fabric according to any one of Items 1 to 5, wherein the light-absorbing heat convertible fiber is a multifilament false twist textured yarn. Item 7. The knitted fabric according to any one of Items 1 to 6, wherein the knitted fabric has a temperature rise of 10°C or more after 1 minute and 15°C or more after 3 minutes as determined in the following artificial sunlight irradiation test. <Artificial sunlight irradiation test> A temperature sensor is attached to the center of the side opposite the one side of the knitted fabric (100 mm x 100 mm), the knitted fabric is placed with the one side facing up, and left to stand in an environment with a temperature of 20°C and a relative humidity of 65%RH. After the temperature of the side opposite the one side of the knitted fabric has stabilized at 20°C, a 500W artificial solar lamp (installed at a height of 20 cm from the knitted fabric) is irradiated with an illuminance of 100,000 lux onto the one side of the knitted fabric. The temperatures of the side opposite the one side of the knitted fabric are measured 1 minute and 3 minutes after the start of irradiation, and the temperature rise after 1 minute and 3 minutes are calculated according to the following calculation formula.

number

[0008] According to the knitted fabric of the present invention, when used as a shoe upper material, it can efficiently radiate heat rays when exposed to sunlight, making it easy for the feet to warm up and providing an excellent warming effect, thereby providing shoes that are suitable for use in cold environments (cold regions, winter, etc.). [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a schematic diagram showing the mock Rhodia structure employed in Example 1. [Diagram 2] FIG. 1 is a schematic diagram showing a mock Rhodia structure used in Example 2. [Diagram 3] FIG. 2 is a schematic diagram showing the mock Rhodia structure used in Comparative Example 1. [Figure 4] FIG. 2 is a schematic diagram showing a mock Rhodia structure used in Comparative Example 2. [Diagram 5] This is an image showing the results of measuring the heat distribution using an infrared thermography device after irradiating artificial sunlight while wearing a shoe (right foot) including an upper material using the knitted fabric obtained in Example 1 and a shoe (left foot) including an upper material using the knitted fabric obtained in Comparative Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The knitted fabric of the present invention is used for a shoe upper material, and is characterized in that it contains light-absorbing and heat-converting fibers containing 1 to 20 mass % of light-absorbing and heat-converting particles, and on one side of the knitted fabric (hereinafter sometimes referred to as the first side), the ratio of the area of ​​the light-absorbing and heat-converting fibers to the total area of ​​the surface (hereinafter sometimes referred to as the "surface exposure rate of the light-absorbing and heat-converting fibers") is 30% or more, and the first side is disposed on the outside of the shoe upper material for use. The knitted fabric of the present invention will be described in detail below.

[0011] [Light absorbing and heat converting fiber] In the present invention, the term "light-absorbing heat converting fiber" refers to a fiber that contains light-absorbing heat converting particles and has the function of absorbing light, converting it into heat rays, and emitting it (light-absorbing heat converting ability). In addition, in the present invention, the term "light-absorbing heat converting particles" refers to particles that have light-absorbing heat converting ability.

[0012] The constituent resin of the light-absorbing and heat-converting fiber is not particularly limited as long as it can be melt-spun, and polymers that have been used as raw materials for fibers can be used.Specific examples of the constituent resin of the light-absorbing and heat-converting fiber include polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate, and polytrimethylene terephthalate; polyamides such as nylon 6, nylon 66, nylon 46, nylon 11, and nylon 12; polyolefins such as polypropylene and polyethylene; polychlorinated polymers such as polyvinyl chloride and polyvinylidene chloride; fluorine-based polymers such as polytetrafluoroethylene and polyvinylidene fluoride; and biomass polymers obtained by chemically polymerizing biomass-derived monomers such as PLA (polylactic acid) and PBS (polybutylene succinate).

[0013] The constituent resin of the light absorbing heat converting fiber may be a copolymer containing two or more constituent monomers in consideration of viscosity, thermal properties, compatibility, etc. For example, in the case of a polyester copolymer (copolymerized polyester), a copolymer of polyester and aromatic dicarboxylic acid such as isophthalic acid and 5-sulfoisophthalic acid; aliphatic dicarboxylic acid such as adipic acid, succinic acid, suberic acid, sebacic acid, and dodecanedioic acid; aliphatic diol such as ethylene glycol, propylene glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol; hydroxycarboxylic acid such as glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxypentanoic acid, hydroxyheptanoic acid, and hydroxyoctanoic acid; or aliphatic lactone such as ε-caprolactone may be used.

[0014] The constituent resin of the light absorbing and heat converting fiber is preferably polyester, and more preferably polyethylene terephthalate.

[0015] The light-absorbing heat converting particles are preferably those capable of converting sunlight into heat rays and radiating the heat rays, and specific examples thereof include carbon black, zirconium carbide, silicon carbide, boron carbide, tin oxide, aluminum oxide, silicon dioxide, mica, talc, and the like. These light-absorbing heat converting particles may be used alone or in combination of two or more. Among these light-absorbing heat converting particles, carbon black and zirconium carbide are preferred from the viewpoints of dispersibility in fibers and stable expression of light-absorbing heat converting ability.

[0016] The average particle size of the light-absorbing heat converting particles is not particularly limited as long as it can be dispersed and retained in the fiber, and may be, for example, 10 μm or less, preferably 0.05 to 1.0 μm, and more preferably 0.05 to 0.5 μm. By using light-absorbing heat converting particles that satisfy this average particle size, clogging of the filter medium and thread breakage can be suppressed in the spinning process. In the present invention, the average particle size of the light-absorbing heat converting particles is the volume average particle size measured using a laser diffraction scattering method particle size distribution measuring device.

[0017] The content of the light-absorbing heat converting particles in the light-absorbing heat converting fiber is set to 1 to 20% by mass. If the content of the light-absorbing heat converting particles is less than 1% by mass, the desired warming effect cannot be obtained when used as a shoe upper material. If the content of the light-absorbing heat converting particles exceeds 20% by mass, the spinnability may deteriorate and the strength of the light-absorbing heat converting fiber may decrease. From the viewpoint of further improving the warming effect, the content of the light-absorbing heat converting particles in the light-absorbing heat converting fiber is preferably 1 to 15% by mass, more preferably 3 to 10% by mass, and particularly preferably 3 to 5% by mass.

[0018] The light absorption-heat converting fiber may be of a single composition, or may be a composite fiber of two or more compositions, such as a core-sheath structure, a side-by-side structure, an island-in-sea structure, a multi-split type, etc. A suitable example of the light absorption-heat converting fiber used in the present invention is a composite fiber of a core-sheath structure.

[0019] When the light-absorbing heat converting fiber has a core-sheath structure, it is sufficient that at least one of the core and the sheath contains light-absorbing heat converting particles, but preferably, the core contains light-absorbing heat converting particles, and the sheath does not contain light-absorbing heat converting particles. In this way, the light-absorbing heat converting fiber with a core-sheath structure in which light-absorbing heat converting particles are contained only in the core has light-absorbing heat converting particles closer to each other, so that the warming effect is efficiently exerted, and even if the content of the light-absorbing heat converting particles is reduced, a sufficient warming effect can be exerted. Furthermore, by reducing the content of the light-absorbing heat converting particles, the spinning operability can be further stabilized.

[0020] A suitable example of a light-absorbing heat-converting fiber having a core-sheath structure is one in which the core is made of a resin composition containing light-absorbing heat-converting particles and polyester (preferably polyethylene terephthalate), and the sheath is made of polyester (preferably polyethylene terephthalate).

[0021] Furthermore, when the light-absorbing and heat-converting fiber has a core-sheath structure in which the light-absorbing and heat-converting particles are contained only in the core, the content of the light-absorbing and heat-converting particles in the core is not particularly limited as long as the content of the light-absorbing and heat-converting particles relative to the total amount of the light-absorbing and heat-converting fiber (total amount of the core and sheath) satisfies the above-mentioned range, and may be, for example, 1.17 to 40 mass%, preferably 1.25 to 21.5 mass%.

[0022] When the light-absorbing heat convertible fiber has a core-sheath structure, the mass ratio of the core to the sheath is not particularly limited, and may be, for example, 50 / 50 to 85 / 15, preferably 70 / 30 to 80 / 20, in terms of the mass ratio of the core to the sheath. By ensuring that the mass ratio of the core to the sheath is within the above range, a more excellent warming effect can be achieved without adversely affecting the spinning operability.

[0023] The light-absorbing and heat-converting fiber may be in the form of either a filament or a staple, preferably a filament. When the light-absorbing and heat-converting fiber is a filament, it may be in the form of either a monofilament or a multifilament, preferably a multifilament.

[0024] The fineness of the light-absorbing and heat-converting fiber (total fineness in the case of multifilament) is not particularly limited, and may be, for example, 10 to 2000 dtex, preferably 30 to 1000 dtex, more preferably 75 to 900 dtex, and even more preferably 75 to 300 dtex. In the present invention, the fineness of the light-absorbing and heat-converting fiber (total fineness in the case of multifilament) is a value measured according to the method specified in "8.3.1 Correct fineness" of "JIS L-1013:2010 Test method for chemical fiber filament yarn".

[0025] In addition, when the light-absorbing and heat-converting fiber is a multifilament, the single-filament fineness is not particularly limited, and may be, for example, 0.5 to 200 dtex, preferably 1 to 20 dtex, more preferably 1 to 10 dtex, and even more preferably 2 to 5 dtex. By using a multifilament having such a single-filament fineness, the fiber surface area is increased, and the light-absorbing and heat-converting ability is improved, making it possible to further enhance the warming effect. In the present invention, the single-filament fineness is a value measured according to the method specified in "8.3.1 Correct fineness" of "JIS L-1013:2010 Chemical fiber filament yarn test method".

[0026] A preferred example of the light-absorbing heat-converting fiber is a multifilament false twisted yarn. The false twisted yarn increases the air space between the filaments due to the crimping form, and as a result, the heat retention effect due to the dead air can be further added. The method of false twisting is not particularly limited, and can be carried out using conventionally known conditions.

[0027] When the light-absorbing heat converting fiber is a multifilament false twisted yarn, the shrinkage rate is not particularly limited, but may be, for example, 10 to 80%, preferably 15 to 50%. When such a shrinkage rate is satisfied, a sufficient air layer can be formed in the knitted fabric, heat retention can be added, and the knitted fabric does not have excessive stretchability, and the generation of excess voids in the knitted fabric can be suppressed. In the present invention, the shrinkage rate is a value measured according to the method specified in "8.3.1 Correct fineness" of "JIS L-1013:2010 Test method for chemical fiber filament yarn".

[0028] [Other constituent fibers] The knitted fabric of the present invention may be composed of only the light-absorbing and heat-converting fibers, or may contain fibers other than the light-absorbing and heat-converting fibers. The type of fibers other than the light-absorbing and heat-converting fibers is not particularly limited, and examples thereof include synthetic fibers having polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate, polyamides such as nylon 6, nylon 66, nylon 46, nylon 11, and nylon 12, and vinylon as a constituent resin; natural fibers such as cotton and hemp; and solvent-spun cellulose fibers such as rayon and lyocell.

[0029] In the knitted fabric of the present invention, the blending ratio of the light-absorbing heat converting fiber is not particularly limited as long as the ratio of the area of ​​the light-absorbing heat converting fiber appearing on the first surface of the knitted fabric satisfies the range described below, but the ratio of the light-absorbing heat converting fiber is, for example, 25% by mass or more, preferably 25 to 100% by mass, and more preferably 50 to 80% by mass. By satisfying such a blending ratio, it is possible to achieve a more excellent warming effect.

[0030] [Surface exposure rate of light absorbing and heat converting fiber] In the knitted fabric of the present invention, the ratio of the area of ​​the light-absorbing heat converting fiber to the total area of ​​the surface on the first surface (one surface; surface arranged on the outside of the shoe upper material) of the knitted fabric is 30% or more. By using a light-absorbing heat converting fiber containing 0.5 to 20% by mass of light-absorbing heat converting particles and having a surface exposure rate of the light-absorbing heat converting fiber of 30% or more, it is possible to efficiently convert sunlight into heat, and to easily warm up and provide an excellent warming effect. Conventionally, in knitted fabrics containing light-absorbing heat converting fibers as constituent fibers, it has been considered that the light-absorbing heat converting fiber should not be arranged on the first surface of the knitted fabric (the surface opposite to the surface in contact with the skin) but should be arranged on the surface opposite to the first surface of the knitted fabric (the surface in contact with the skin) from the viewpoints of heat retention, dyeability, color development, etc. However, in the present invention, contrary to the general understanding of those skilled in the art, a predetermined amount of light-absorbing heat-converting fiber is deliberately arranged on the first side of the knitted fabric (the side opposite to the side that comes into contact with the skin; the side that is placed on the outside of the shoe upper material), making it possible to easily warm up and achieve an excellent warming effect.

[0031] From the viewpoint of further improving the warming effect, the surface exposure rate of the light-absorbing heat-converting fiber is preferably 32 to 100%, more preferably 50 to 100%, further preferably 60 to 100%, and particularly preferably 100%.

[0032] In the present invention, the surface exposure rate of the light-absorbing and heat-converting fiber is a value measured by the following method. <Method for estimating the surface exposure rate of light-absorbing heat-converting fibers> The first surface of the knitted fabric is photographed with a digital microscope to obtain an image of the first surface of the knitted fabric. The obtained image is then processed to calculate the ratio of the area where the light-absorbing heat convertible fiber is present to the total area of ​​the first surface as the "surface exposure rate of the light-absorbing heat convertible fiber."

[0033] [edited organization] In the knitted fabric of the present invention, the knitting structure is not particularly limited as long as the surface exposure rate of the light absorbing heat converting fiber satisfies the above range, but examples thereof include mock Rhodia structure, russell structure, double russell structure, tricot structure, circular knit structure, flat knit structure, etc. Among these, mock Rhodia structure is preferable because it has excellent physical properties as a shoe upper material.

[0034] [Metaku] The weight of the knitted fabric of the present invention is not particularly limited, but is, for example, 150 to 1000 g / m 2 , preferably 200 to 700 g / m 2 , more preferably 300 to 450 g / m 2 In the knitted fabric of the present invention, the basis weight is set to 1000 g / m in order to reduce the weight and stuffiness inside the shoe. 2 Below, especially 450g / m 2 In the present invention, the basis weight of the knitted fabric is a value measured according to the method specified in "Method A (JIS method)" of "8.3.2 Mass per unit area under standard conditions" of "JIS L-1096:2010 Fabric testing methods for woven and knitted fabrics."

[0035] Thickness The thickness of the knitted fabric of the present invention is not particularly limited, as long as it can be used as an upper material for shoes, and may be, for example, 0.1 to 5 mm, preferably 0.2 to 3 mm. The knitted fabric of the present invention can provide an excellent warming effect even if the thickness is reduced to 5 mm or less, particularly 3 mm or less, in order to reduce weight. In the present invention, the thickness of the knitted fabric is a value measured according to the method specified in "8.4 Thickness" "A Method (JIS Method)" of "JIS L-1096:2010 Fabric Testing Methods for Woven and Knitted Fabrics."

[0036] [Heat generation characteristics] When exposed to sunlight, the knitted fabric of the present invention can efficiently convert sunlight into heat rays by the light-absorbing heat converting fiber, and when used as an upper material for shoes, the feet can be easily warmed and an excellent warming effect can be achieved. An example of the warming effect that the knitted fabric of the present invention can have is a temperature rise of 10°C or more after 1 minute and a temperature rise of 15°C or more after 3 minutes, as determined in the following artificial sunlight irradiation test. A more preferable example of the knitted fabric of the present invention is a temperature rise of 12 to 18°C ​​after 1 minute and a temperature rise of 20 to 31°C after 3 minutes. <Artificial sunlight irradiation test> A temperature sensor is attached to the center of the side opposite the first side of the knitted fabric (100mm x 100mm), and the knitted fabric is placed with the first side facing up and left to stand in an environment with a temperature of 20°C and a relative humidity of 65%RH. After the temperature of the side opposite the first side of the knitted fabric has stabilized at 20°C, a 500W artificial solar lamp (installed 20cm above the knitted fabric) is irradiated with an illuminance of 100,000 lux onto the first side of the knitted fabric. The temperatures of the side opposite the first side of the knitted fabric are measured 1 minute and 3 minutes after the start of irradiation, and the temperature rise after 1 minute and 3 minutes is calculated according to the formula below.

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[0037] [Application] The knitted fabric of the present invention is used for a shoe upper material. The shoe upper material is a part of a shoe that covers and encases the instep of the foot. The knitted fabric of the present invention may be used to form at least a part of the shoe upper material, and is preferably used for at least the part that covers the instep of the foot.

[0038] The first side of the knitted fabric of the present invention (the side in which the surface exposure rate of the light-absorbing heat converting fiber is set to 30% or more) is disposed on the outside of the shoe upper material, and the side opposite to the first side of the knitted fabric of the present invention is disposed on the inside of the shoe upper. Here, the outside of the shoe upper is the side located opposite to the user's foot, and the inside of the shoe upper is the side facing the user's foot.

[0039] The first side of the knitted fabric of the present invention needs to form the outermost surface of the shoe upper material, but the side opposite to the first side of the knitted fabric of the present invention does not need to form the innermost surface of the shoe upper. In other words, the side opposite to the first side of the knitted fabric of the present invention does not need to be arranged as the innermost surface of the shoe upper by laminating another fabric or the like on the side opposite to the first side of the knitted fabric of the present invention.

[0040] The type of shoe to which the shoe upper using the knitted fabric of the present invention is applied is not particularly limited, but examples include sneakers, sports shoes for running and various sports, and daily rehabilitation shoes.

[0041] A shoe is provided by joining a shoe upper formed using the knitted fabric of the present invention to a sole. EXAMPLES

[0042] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0043] 1. Manufacturing and evaluation of knitted fabrics [Measurement method / Evaluation method] In the examples and comparative examples, the single yarn fineness, total fineness, basis weight, surface exposure rate of the light absorbing and heat converting fiber, and heat generation characteristics were measured and evaluated by the following methods.

[0044] Single yarn size, total size The single yarn fineness and total fineness were measured according to the method specified in "JIS L-1013:2010 Chemical fiber filament yarn test method" in "8.3.1 Correct fineness".

[0045] Appraisal The weight of the knitted fabric was measured according to the method specified in "JIS L-1096:2010 Fabric test methods for woven and knitted fabrics," "8.3.2 Mass per unit area under standard conditions," "Method A (JIS method)."

[0046] Thickness The thickness of the knitted fabric was measured according to the method specified in "8.4 Thickness" "Method A (JIS method)" of "JIS L-1096:2010 Fabric test methods for woven and knitted fabrics."

[0047] Surface exposure rate of light absorbing and heat converting fiber The first surface of the knitted fabric was photographed with a digital microscope (VHX-900 digital microscope manufactured by Keyence Corporation) to obtain an image of the first surface of the knitted fabric. The obtained image was then processed, and the ratio of the area where the light-absorbing heat convertible fiber was present to the total area of ​​the first surface was calculated as the "surface exposure rate of the light-absorbing heat convertible fiber."

[0048] Heat generation characteristics A knitted fabric cut to a size of 100 mm x 100 mm was prepared. A temperature sensor was attached to the center of the surface opposite to the first surface of the knitted fabric, and the knitted fabric was placed with the first surface facing up and left to stand in an environment of 20°C temperature and 65% RH relative humidity. After the temperature of the surface opposite to the first surface of the knitted fabric stabilized at 20°C, irradiation was started with an illuminance of 100,000 lux using a concentrated artificial solar irradiation lamp (Solar light "XC-100" manufactured by Ceric, 500 watts) installed at a height of 20 cm from the knitted fabric. The temperature of the surface opposite to the first surface of the knitted fabric was measured 1 minute and 3 minutes after the start of irradiation, and the temperature rise after 1 minute and 3 minutes were calculated according to the following calculation formula.

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[0049] [Fabric manufacturing] Example 1 A polyethylene terephthalate resin (intrinsic viscosity 0.65) was used for the sheath component. On the other hand, a resin composition containing 1.25% by mass of carbon black particles (average particle size 0.4 μm) and 98.75% by mass of polyethylene terephthalate resin (intrinsic viscosity 0.65) was used for the core component. Using a composite spinning device having a core-sheath composite nozzle plate with 48 holes, the sheath component and the core component were spun at a spinning temperature of 295 ° C. and 3000 m / min so that the mass ratio of the core to the sheath (core / sheath) was 80 / 20, and a semi-undrawn yarn of 280 dtex / 48 filaments was obtained. Next, the obtained semi-undrawn yarn was false twisted at a draw ratio of 1.7 times and a false twist speed of 600 m / min using a high-speed false twisting machine "TMC-1" manufactured by TMT Machinery Co., Ltd., to obtain a false twist textured yarn (165 dtex / 48 filaments) of a light-absorbing heat convertible fiber with a core-sheath structure. The content of carbon black particles in the entire light absorbing and heat converting fiber was 1% by mass.

[0050] Next, the obtained false twisted yarn of the light-absorbing and heat-converting fiber and a commercially available false twisted yarn (165 dtex / 48 filaments) were used to knit in a Mock Rhodia structure as shown in Figure 1 on a circular knitting machine ("LPJ-H", manufactured by Fukuhara Seiki Mfg. Co., Ltd.; 33" x 22G) so that the false twisted yarn of the light-absorbing and heat-converting fiber was knitted over the entire first side of the knitted fabric (the side opposite the skin side). The blend ratio of the false twisted yarn of the light-absorbing and heat-converting fiber in the obtained knitted fabric was 76.5% by mass.

[0051] Next, using a circular dyeing tester (Hisaoka Works, "CUT-TS type"), a surfactant (Nicca Chemical Co., Ltd., Sunmol FL) was used at a concentration of 1g / L, and a bath ratio of 1:25 was used for relaxation scouring at 80°C for 30 minutes. Next, in order to dye the knitted fabric using the same circular dyeing tester as above, a treatment solution containing 1% omf of dye (Dystar Co., Ltd., "Dianix Blue UN-SE"), 0.2 ml / L of acetic acid as a dyeing assistant, and 0.5 g / L of a leveling agent (Nicca Chemical Co., Ltd., "Nikka Sunsalt SN-130") was used for hot water treatment at 130°C for 30 minutes, and then finish setting was performed. The obtained knitted fabric had a width of 165 cm and a basis weight of 395 g / m. 2, the thickness was 0.65 mm.

[0052] Example 2 A knitted fabric was obtained under the same conditions as in Example 1, except that the mock Rhodia structure shown in Figure 2 was knitted so that the surface exposure rate of the light-absorbing heat converting fiber on the first side of the knitted fabric was 32.2%. The knitted fabric obtained had a width of 165 cm and a basis weight of 360 g / m 2 The blend ratio of the false twist textured yarn of the light absorbing and heat converting fiber in the obtained knitted fabric was 53.7%.

[0053] Example 3 A knitted fabric was obtained under the same conditions as in Example 1, except that the carbon black particle content of the light-absorbing heat converting fiber was changed to 15% by mass (the carbon black particle content in the core was 18.75% by mass). The obtained knitted fabric had a width of 165 cm and a basis weight of 395 g / m 2 , the thickness was 0.65 mm.

[0054] Example 4 A knitted fabric was obtained under the same conditions as in Example 1, except that the mass ratio of the core and sheath of the light-absorbing and heat-converting fiber (core / sheath) was changed to 50:50 and the content of carbon black particles in the core was changed to 2.0 mass%. The obtained knitted fabric had a width of 165 cm and a basis weight of 395 g / m 2 The thickness was 0.65 mm. The content of carbon black particles in the entire light absorbing and heat converting fiber was 1 mass %.

[0055] Example 5 A knitted fabric was obtained under the same conditions as in Example 1, except that the carbon black particles contained in the core of the light-absorbing heat converting fiber were replaced with zirconium carbide (average particle size 0.5 μm). The obtained knitted fabric had a width of 165 cm and a basis weight of 395 g / m. 2 The thickness was 0.65 mm. The content of carbon black particles in the entire light absorbing and heat converting fiber was 1 mass %.

[0056] Comparative Example 1 A knitted fabric was obtained under the same conditions as in Example 1, except that the mock Rhodia structure shown in Figure 3 was knitted so that the surface exposure rate of the light-absorbing heat converting fiber on the first side of the knitted fabric was 0%. The knitted fabric obtained had a width of 165 cm and a basis weight of 395 g / m 2 The knitted fabric had a thickness of 0.65 mm. The blend ratio of false twisted yarn of the light absorbing and heat converting fiber in the obtained knitted fabric was 0%, and only commercially available false twisted polyester yarn was used.

[0057] Comparative Example 2 A knitted fabric was obtained under the same conditions as in Example 1, except that the mock Rhodia structure shown in FIG. 4 was knitted so that the surface exposure rate of the light-absorbing heat converting fiber on the first side of the knitted fabric was 24.5%. The knitted fabric obtained had a width of 165 cm and a basis weight of 395 g / m 2 The blending ratio of the false twist textured yarn of the light absorbing and heat converting fiber in the obtained knitted fabric was 12.5%.

[0058] Comparative Example 3 A knitted fabric was obtained under the same conditions as in Example 1, except that the carbon black particle content of the light-absorbing heat converting fiber was changed to 0.5% by mass (the carbon black particle content in the core was 0.625% by mass). The obtained knitted fabric had a width of 165 cm and a basis weight of 395 g / m 2 , the thickness was 0.65 mm.

[0059] [Evaluation results of knitted fabric] The results of evaluating each knitted fabric are shown in Table 1. When the knitted fabric contained light-absorbing heat converting fibers containing 1 to 20% by mass of light-absorbing heat converting particles and the surface exposure rate of the light-absorbing heat converting fibers on the first side of the knitted fabric was 30% or more, the temperature rise after 1 minute in the artificial sunlight irradiation test was 10°C or more and the temperature rise after 3 minutes was 15°C or more, and an excellent warming effect was achieved by artificial sunlight irradiation (Examples 1 to 5). In contrast, even when the knitted fabric contained light-absorbing heat converting fibers containing 1 to 20% by mass of light-absorbing heat converting particles, when the surface exposure rate of the light-absorbing heat converting fibers on the first side of the knitted fabric was less than 30%, the warming effect by artificial sunlight irradiation was insufficient (Comparative Examples 1 and 2). Furthermore, even when the surface exposure rate of the light-absorbing heat converting fibers on the first side of the knitted fabric was 100%, and the light-absorbing heat converting particles in the light-absorbing heat converting fibers were less than 1% by mass, the warming effect by artificial sunlight irradiation was insufficient (Comparative Example 3).

[0060] From the above results, it was confirmed that a knitted fabric containing light-absorbing heat-converting fiber containing 1 to 20 mass% light-absorbing heat-converting particles and having a surface exposure rate of the light-absorbing heat-converting fiber of 30% or more on one side of the knitted fabric exhibits an excellent thermal effect when exposed to sunlight, and is therefore useful as an upper material for shoes.

[0061] [Table 1]

[0062] 2. Manufacturing and evaluation of shoe upper materials (1) A shoe upper material was formed using the knitted fabric obtained in Example 1. In the shoe upper material, the first surface of the knitted fabric (the surface on which the light-absorbing heat converting fiber is exposed at 100%) was arranged on the outside (the side facing away from the user's foot), and the surface opposite to the first surface of the knitted fabric was arranged on the inside (the side facing the user's foot). The obtained shoe upper was joined to a sole to produce a shoe.

[0063] When the obtained shoes were worn and exposed to sunlight, the feet felt warm immediately, as if the feet were placed under an electric blanket. From this result, it was revealed that shoes including shoe uppers formed from the knitted fabric of the present invention can prevent the feet from getting cold even in cold environments, and can provide a comfortable fit.

[0064] 3. Manufacturing and evaluation of shoe upper materials (2) A shoe upper material was formed using the knitted fabric obtained in Example 1. In the shoe upper material, the first surface of the knitted fabric (the surface on which the light absorbing heat converting fiber is 100% exposed) was arranged on the outer side (the side facing away from the user's foot), and the surface opposite to the first surface of the knitted fabric was arranged on the inner side (the side facing the user's foot).

[0065] Similarly, a shoe upper material was formed using the knitted fabric obtained in Comparative Example 1. In the shoe upper material, the first surface of the knitted fabric (the surface on which the light absorbing heat converting fiber is exposed at 0%) was arranged on the outer side (the side facing away from the user's foot), and the surface opposite to the first surface of the knitted fabric was arranged on the inner side (the side facing the user's foot).

[0066] The subject sat down wearing a shoe using the knitted fabric obtained in Example 1 as the upper material on the right foot and a shoe using the knitted fabric obtained in Comparative Example 1 as the upper material on the left foot, and started irradiation with a concentrated artificial solar light (Solar light "XC-100" manufactured by Ceric, 500 watts) installed 20 cm above the floor at an illuminance of 100,000 lux. Three minutes after the start of irradiation, thermal distribution images of both feet were obtained using an infrared thermography device.

[0067] The results are shown in Figure 5. As is clear from Figure 5, the temperature of the right foot is significantly higher than that of the left foot, and it was confirmed that an excellent warming effect can be obtained by wearing shoes using the knitted fabric obtained in Example 1 as the upper material. [Explanation of symbols]

[0068] C cylinder needle Y dial needle F1~F6: Yarn feeder number a: False twisted yarn made of light absorbing and heat converting fiber b: Commercially available polyester false twist yarn

Claims

1. A knitted fabric used for shoe upper materials, The light-absorbing and heat-converting fiber contains 1 to 20 mass % of light-absorbing and heat-converting particles, the light-absorbing and heat-converting fiber is a multifilament composed of a single yarn having a core-sheath structure, the single yarn containing the light-absorbing and heat-converting particles only in the core portion, On one side of the knitted fabric, the ratio of the area of ​​the light-absorbing heat converting fiber to the total area of ​​the surface is 30% or more; The knitted fabric is used with the one surface being placed on the outside of a shoe upper material.

2. The knitted fabric according to claim 1 , wherein the light absorbing and heat converting particles are at least one selected from the group consisting of carbon black, zirconium carbide, silicon carbide, boron carbide, tin oxide, aluminum oxide, silicon dioxide, mica, and talc.

3. The knitted fabric according to claim 1 or 2, wherein a mass ratio of the core to the sheath is 50 / 50 to 85 / 15 in terms of a core / sheath mass ratio.

4. The knitted fabric according to any one of claims 1 to 3, wherein the constituent resin of the core is polyester, and the constituent resin of the sheath is polyester.

5. The knitted fabric according to any one of claims 1 to 4, wherein the light-absorbing heat convertible fiber is a multifilament false twist textured yarn.

6. The knitted fabric according to any one of claims 1 to 5, wherein the temperature rise after 1 minute is 10°C or more and the temperature rise after 3 minutes is 15°C or more as determined in the following artificial sunlight irradiation test. <Artificial sunlight irradiation test> A temperature sensor is attached to the center of the side opposite to the one side of the knitted fabric (100 mm x 100 mm), and the knitted fabric is placed with the one side facing up and left to stand in an environment of a temperature of 20°C and a relative humidity of 65% RH. After the temperature of the surface opposite to the one side of the knitted fabric has stabilized at 20° C., a 500 W artificial solar lamp (installed at a height of 20 cm from the knitted fabric) is irradiated to the one side of the knitted fabric at an illuminance of 100,000 lux. The temperatures of the surface opposite to the one side of the knitted fabric are measured 1 minute and 3 minutes after the start of irradiation, and the temperature rise after 1 minute and 3 minutes is calculated according to the following calculation formula. [0010]

7. A shoe upper material comprising the knitted fabric according to any one of claims 1 to 6.

8. A shoe comprising the shoe upper material according to claim 7.

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