JP2013147785A - Regenerated cellulose fiber with photothermal conversion property, method for producing the same and fiber structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a regenerated cellulose fiber with photothermal conversion properties, which has photothermal conversion particles dispersed in the fiber in a fine particle state, has a high photothermal conversion function, has adequate antistatic properties, and has almost the same properties such as a color tone and texture as a usual rayon fiber; a method for producing the same; and a fiber structure.SOLUTION: The regenerated cellulose fiber contains the photothermal conversion particles having heat ray absorbing properties in the fiber. The photothermal conversion particle is a particle having a BET specific surface area of in a range of 5-120 m/g and a powder resistance of less than 30 Ω cm, and is contained in the fiber in a dispersed state. The method for producing the regenerated cellulose fiber comprises: preparing an aqueous dispersion liquid of the photothermal conversion particles; mixing the aqueous dispersion liquid with a viscose stock solution containing cellulose to prepare a viscose solution for spinning; extruding the viscose solution for spinning from a nozzle to form a fiber; and coagulating and regenerating the fiber.

Description

  The present invention relates to a photothermal-convertible regenerated cellulose fiber, a method for producing the same, and a fiber structure. More specifically, the present invention relates to a rayon fiber containing a specific inorganic additive, a method for producing the same, and a fiber structure.

  It is known that rayon fibers using regenerated cellulose are produced by various methods such as viscose method, copper ammonia method, and solvent spinning method. It is known that rayon fibers themselves absorb moisture and generate heat because the substrate is cellulose. In recent years, heat ray radiating fibers and photothermal conversion fibers have been proposed in addition to hygroscopic heat generation.

  Patent Document 1 proposes that a conductive zinc oxide doped with a metal such as aluminum is included in a fiber as an n-type semiconductor having a volume resistivity of 30 to 500 Ω · cm. Patent Documents 2 to 3 propose that the metal oxide inorganic particles are kneaded into the polyester fiber. Patent Document 4 proposes kneading inorganic particles into a core component in a polyester composite fiber having a core-sheath structure. Patent Document 5 proposes that a zinc oxide powder having a specific particle diameter is kneaded into a thermoplastic fiber such as polyester or nylon.

JP 2000-154419 A JP 2006-307383 A JP 2008-075184 A JP 2003-027337 A Japanese Patent No. 4228856

  However, in Patent Document 1, the temperature difference during heat generation is as small as 0.3 to 0.6 ° C., and the temperature difference perceived by humans is about 0.5 ° C., and so high heat generation cannot be expected. Further, in Patent Documents 2 to 5, since the base is a thermoplastic resin, the aqueous dispersion of particles cannot be used and dry particles (dry powder) must be used. However, there is a problem that the spinnability is lowered and the high elongation is lowered. Moreover, since the fiber strength will fall when the synthetic fiber of patent documents 1-5 contains a large amount of inorganic particles, there was a problem that the addition amount of inorganic particles was restricted and sufficient heat ray absorption ability was not obtained. . Furthermore, since the fiber of patent document 3 or patent document 5 is a fiber which reflects a heat ray positively, ie, has a heat ray shielding effect, it did not have sufficient heat storage and heat retention.

  In order to solve the above-mentioned conventional problems, the present invention provides a regenerated cellulose fiber having a high light-heat conversion function, in which light-heat convertible particles can be dispersed in the form of fine particles, a method for producing the same, and a fiber structure. . Furthermore, the present invention provides a photothermal-convertible regenerated cellulose fiber that has good antistatic properties and has characteristics such as color tone and texture that are not significantly different from ordinary regenerated cellulose fibers, a method for producing the same, and a fiber structure.

The light-heat convertible regenerated cellulose fiber of the present invention is a regenerated cellulose fiber containing light-heat convertible particles having heat-absorbing ability in the fiber, and the light-heat convertible particles have a BET specific surface area of 5 to 120 m ² / g. It is characterized by containing particles having a powder resistance of less than 30 Ωcm within a range in a dispersed state.

The method for producing the photothermal-convertible regenerated cellulose fiber of the present invention is a method for producing the photothermal-convertible regenerated cellulose fiber, wherein the BET specific surface area is in the range of 5 to 120 m ² / g, and the powder resistance is 30 Ωcm. An aqueous dispersion of light-to-heat convertible particles is prepared, and the viscose stock solution containing cellulose is mixed with the aqueous dispersion to prepare a spinning viscose liquid, and the spinning viscose liquid is extruded from a nozzle. It is characterized by spinning and coagulating.

  The fiber structure of the present invention contains the above-mentioned photothermal conversion regenerated cellulose fiber.

  INDUSTRIAL APPLICABILITY The present invention can provide a regenerated cellulose fiber having an immediate effect and a high photothermal conversion function by allowing the regenerated cellulose fiber to have photothermal conversion particles satisfying a predetermined BET specific surface area and powder resistance in a dispersed state. In addition, the present invention can provide a light-heat-convertible regenerated cellulose fiber that has good antistatic properties and has characteristics such as color tone and texture that are not significantly different from ordinary rayon fibers. In particular, it is possible to provide fibers that become warm and warm by sunlight (especially near infrared rays). Fibers warmed by sunlight are underwear, innerwear, outerwear, mufflers, stalls, hats, ear hooks, gloves, and other clothing products, wallpaper, shoji paper, carpets, curtains, and other interior products, blankets, duvet covers, sheets It is useful for bedding such as pillow covers.

  The production method of the present invention comprises preparing an aqueous dispersion of photothermal conversion particles satisfying a predetermined BET specific surface area and powder resistance, mixing the aqueous dispersion with a viscose stock solution containing cellulose, and spinning viscose. A liquid is prepared, and the spinning viscose liquid is extruded from a nozzle, spun, and coagulated and regenerated, whereby the photothermal conversion particles can be present in the regenerated cellulose fiber in a finely dispersed state. Thereby, the regenerated cellulose fiber which has a high photothermal conversion function with an immediate effect can be provided. Further, it is possible to provide a photothermal-convertible regenerated cellulose fiber having a good color tone and good antistatic properties.

  The fiber structure of the present invention can be given the performance of warming up immediately due to the function of generating heat by receiving sunlight, in addition to the performance of the regenerated cellulose fiber itself on the skin.

FIG. 1 is a transmission optical micrograph (magnification 640 times) showing a cross section of a photothermal conversion rayon fiber in one example of the present invention. FIG. 2 is an explanatory view showing a heat storage test method in one embodiment of the present invention. FIG. 3 is a temperature change graph showing the results of the heat storage property test in Experiment 1 of Example 9 of the present invention. FIG. 4 is a temperature change graph showing the results of the heat storage property test in Experiment 2 of Example 9 of the present invention. FIG. 5 is a temperature change graph showing the results of the heat storage property test in Experiment 3 of Example 9 of the present invention. FIG. 6 is a temperature change graph showing the results of the heat storage property test in Experiment 4 of Example 9 of the present invention. FIG. 7 is a temperature change graph showing the results of the heat storage property test in Experiment 5 of Example 9 of the present invention. FIG. 8 is a temperature change graph showing the results of the heat storage property test in Experiment 6 of Example 9 of the present invention. FIG. 9 is a graph showing the results of near-infrared absorptance in Example 1 (Fiber A), Example 3 (Fiber C), and Comparative Example 1 (Fiber E) of the present invention. FIG. 10 is a temperature change graph showing the results of the heat storage test of Example 1 (Fiber A), Example 5 (Fiber G), Example 6 (Fiber H), and Comparative Example 1 (Fiber E) of the present invention. is there. FIG. 11 shows the heat storage test of Example 1 (Fiber A), Example 2 (Fiber B), Example 7 (Fiber I), Comparative Example 1 (Fiber E), and Comparative Example 3 (Fiber K) of the present invention. It is a temperature change graph which shows the result of. FIG. 12 is a temperature change graph showing the results of thermal storage tests of Example 1 (Fiber A), Example 8 (Fiber J), Comparative Example 1 (Fiber E), and Comparative Example 4 (Fiber L) of the present invention. is there. FIG. 13 is a transmission optical micrograph (magnification 320 times) showing the side surface of the photothermal conversion rayon fiber in one example of the present invention. FIG. 14 is a transmission optical micrograph (magnification 320 times) showing a side surface of the photothermal conversion rayon fiber in another embodiment of the present invention.

  This invention contains the photothermal conversion particle | grains which have a predetermined heat ray absorption ability in a regenerated cellulose fiber. Absorption of near-infrared wavelengths (780-2100 nm) by the photothermal conversion particles kneaded into the cellulose fibers causes the particles to vibrate within the cellulose molecules, thereby providing heat and an exothermic effect. To do this, for example, the aqueous dispersion of the particles is mixed with a viscose stock solution containing cellulose to obtain a spinning viscose liquid, and this spinning viscose liquid is extruded from a nozzle and wet-spun. Can be obtained. As a result, the particles are present in the fibers in a state of being finely dispersed in the aqueous dispersion or in a state close thereto. The photothermal conversion particles kneaded into the fiber are almost uniformly dispersed inside the fiber, and can be confirmed from the side of the fiber using an optical microscope or the like.

The photothermal conversion particles preferably have a BET specific surface area in the range of 5 to 120 m ² / g. High heat ray absorptivity and photothermal conversion property are acquired as it is this range. The BET specific surface area is measured according to the BET specific surface area method defined in JIS R 1626. A preferred BET specific surface area is in the range of 5 to 110 m ² / g, more preferably in the range of 20 to 100 m ² / g. A more preferable range is 70 to 90 m ² / g.

  When the photothermal conversion particles are contained alone in the photothermal conversion regenerated cellulose fiber, the photothermal conversion particles are preferably present in a range of 1 to 15% by mass, more preferably 1.5 to 1.5%. It is the range of 15 mass%, More preferably, it is the range of 2-10 mass%. Within this range, higher heat ray absorbability and photothermal conversion are obtained. In addition, when regenerated cellulose is used, even if more photothermal conversion particles are contained compared to synthetic resin, fiber strength degradation is low, and cellulose contains more moisture than synthetic resin. Therefore, the heat storage property can be exhibited more efficiently. When the photothermal conversion regenerated cellulose fiber contains the photothermal conversion particles and other particles described later in combination, the photothermal conversion particles are preferably present in the range of 0.5 to 10% by mass. More preferably, it is the range of 1-8 mass%, More preferably, it is the range of 1.5-5 mass%.

The product of the BET specific surface area of the photothermal conversion particles and the content of the photothermal conversion particles in the fiber is preferably in the range of 0.5 to 3.5. If it is the said range, still higher heat ray absorptivity and photothermal conversion property will be obtained. The product of the BET specific surface area of the photothermal conversion particles and the content in the fiber is a value corresponding to the total specific surface area of the particles in the fiber. For example, when the BET specific surface area of the particles is 5 m ² / g and the content in the fiber is 10% by mass, the product is 5 × 0.1 = 0.5. In addition, generally, when inorganic particles are added to the fiber, the hue is lowered, but if the product of the BET specific surface area of the photothermal conversion particles and the content in the fiber is within the above range, the heat ray absorbability and the photothermal conversion property Both hue characteristics can be achieved. That is, by using particles with a large specific surface area, the area where light hits can be increased and photothermal conversion can be performed with high efficiency. On the other hand, when the content of particles is large, the hue of the fiber is influenced by the hue of the particles. Therefore, by optimizing the specific surface area of the particles and the content of the particles, it is possible to achieve both the heat ray absorptivity, the photothermal conversion property and the hue.

  The powder resistance of the photothermal conversion particles is preferably less than 30 Ωcm. A more preferable powder resistance is 1 to 20 Ωcm, and even more preferably 2 to 15 Ωcm. In addition, the powder resistance of the particles is obtained as an electric resistance value (Ωcm) of a green compact obtained by pressing the powder at 9.807 MPa. The powder resistance of particles is originally used as an index for evaluating electrical conductivity, but in the present invention, it is used as an index representing the conductivity of heat converted from light. In addition, when the powder resistance is less than 30 Ωcm, the antistatic property of the fiber is improved, and even when used in a dry state in winter, static electricity is reduced and uncomfortable feeling can be reduced. In particular, it is preferable to use in combination with a highly charged material such as acrylic fiber or wool, since the heat retention when a fiber structure is obtained is improved.

  Regarding the particle size of the photothermal conversion particles, when provided as dry particles, the average primary particle size (50% particle size) measured by electron micrograph is 0.005 to 0.5 μm. preferable. More preferably, it is 0.01-0.3 micrometer. On the other hand, when the photothermal conversion particles are provided as an aqueous dispersion, the average secondary particle size (50% particle size) measured by a laser diffraction light scattering method is 0.05 to 0.8 μm. preferable. More preferably, it is 0.07 to 0.4 μm. When the particle diameter is within such a range, the light scattering effect is small, and high heat absorption and photothermal conversion are obtained.

The photothermal conversion particles are preferably at least one particle selected from the group consisting of, for example, the following (1), the following (2), zirconium carbide, titanium carbide, and tin oxide. Among these, at least one particle selected from the following (1) and the following (2) is more preferable.
(1) Fine particles obtained by doping tin oxide with antimony (Sn0 ₂ / Sb dope).
(2) fine particles coated with antimony-doped tin oxide titanium oxide (Ti0 _2, Sn0 ₂ / Sb-doped).

  Regarding the particle diameters of the particles (1) and (2), the particles (1) (fine particles obtained by doping tin oxide with antimony, hereinafter also referred to as “ATO particles”) have an average primary particle size of 0. It is preferable that it is 005-0.1 micrometer, More preferably, it is 0.01-0.05 micrometer. The (1) particles preferably have an average secondary particle size in an aqueous dispersion of 0.05 to 0.5 μm, more preferably 0.07 to 0.2 μm. The ATO particles used in the present invention are highly transparent particles, and have low powder resistance and high conductivity. Therefore, such a fine particle has a small content (contains, for example, 1% by mass in the fiber). Rate), sufficient heat ray absorptivity and photothermal conversion can be obtained. In addition, since ATO particles are highly transparent particles, light reflection in the fiber is small, and thus it can be said that the light absorption is high. The preferable content of ATO particles, when contained alone, is 1 to 15% by mass with respect to cellulose (relative to cellulose), more preferably 1.5 to 15% by mass, and further preferably 2 to 10%. % By mass. When mixing in combination with other particles to be described later, the ATO particles are preferably 0.5 to 10% by mass, more preferably 1 to 8% by mass, and even more preferably 1.5 to 5% by mass. It is a range.

  The (2) particles (fine particles obtained by coating titanium oxide with antimony-doped tin oxide, hereinafter also referred to as “Ti / ATO particles”) preferably have an average primary particle size of 0.01 to 0.5 μm in dry particles. More preferably, it is 0.02-0.3 micrometer. The (2) particles preferably have an average secondary particle diameter in the aqueous dispersion of 0.02 to 0.8 μm, more preferably 0.03 to 0.4 μm. The Ti / ATO particles used in the present invention can impart a white color tone because titanium oxide is a base particle, and the visible light permeability is lowered and the transparency is high. The content of preferable Ti / ATO particles is 1 to 15% by mass, more preferably 1.5 to 15% by mass, and further preferably 2 to 10% by mass with respect to cellulose, when contained alone. is there. When mixing in combination with other particles to be described later, the Ti / ATO particles are preferably 0.5 to 10% by mass, more preferably 1 to 8% by mass, and even more preferably 1.5 to 5% by mass. % Range.

The preferred range of BET specific surface area in the ATO particles are 50~120m ² / g in consideration of the light-to-heat conversion property and hue, more preferably 60~100m ² / g, more preferably 70~90m ² / g. On the other hand, the range of preferred BET specific surface area in the Ti / ATO particles is 5 to 50 m ² / g in consideration of the light-to-heat conversion property and hue, more preferably 6~40m ² / g, more preferably 6 to 10 m ² / g.

  A preferable range of the powder resistance in the ATO particles is 1 to 25 Ωcm, more preferably 1 to 10 Ωcm, and even more preferably 2 to 5 Ωcm in consideration of photothermal conversion and antistatic properties. The range of the preferable powder resistance in the Ti / ATO particles is 1 to 25 Ωcm, more preferably 1 to 10 Ωcm, and further preferably 2 to 5 Ωcm in consideration of photothermal conversion and antistatic properties.

The light-heat-convertible regenerated cellulose fiber has a near-infrared average transmittance of 20% or less, a near-infrared average reflectance of 40% or less, and visible light when formed into a hydroentangled nonwoven fabric (weight per unit: 60 g / m ² ) of 100% by mass of raw cotton. The average transmittance is preferably 20% or more. More preferably, the near-infrared average transmittance is 15% or less, the near-infrared average reflectance is 35% or less, and the visible light average transmittance is 30% or more.

  Visible light has a wavelength of 380 to 780 nm, and near infrared light has a wavelength of 780 to 2100 nm. Visible light transmittance, near-infrared transmittance, and near-infrared reflectance can be used as an index indicating the photothermal conversion property (heat storage property) of the fiber. When the visible light transmittance is low, the transmission is reduced by the shielding effect by the particles in the fiber. On the other hand, since the number of particles increases in the fiber, the fiber itself may be insufficient in strength. Near-infrared transmittance and near-infrared reflectance are reflected, transmitted, and absorbed when light strikes the fiber. By setting the above range, the light absorption ratio is high, and the heat conversion property is high. .

  When the ATO particles are used as the photothermal conversion particles, they are conductive particles having higher transparency than when Ti / ATO particles are used. Absorbs more light in the infrared region and converts it into heat, and tends to have a high absorption rate on the long wavelength side (around 1500 to 2100 nm).

Generally, it is said that the value obtained by adding the transmittance, reflectance, and absorptance of an object is 100%. Therefore, the photothermal-convertible regenerated cellulose fiber of the present invention is a hydroentangled nonwoven fabric of 100% by mass of raw cotton (60 g / m ² basis weight). ), The near infrared absorptance is preferably 50% or more in the wavelength range of 1500 to 2100 nm. A more preferable near-infrared absorptance is 60% or more. In particular, in the present invention, it is preferable to use ATO particles having a predetermined average particle diameter and powder resistance because the near-infrared absorptance increases as the wavelength increases.

  The photothermal conversion regenerated cellulose fiber of the present invention may contain other particles in addition to the above-described photothermal conversion particles. It is preferable that the photothermal exchangeable particles and other particles coexist in the fiber because heat storage tends to be further improved. In the state where photothermal exchangeable particles and other particles are present in the fiber, the photothermal exchangeable particle serves as a heating element and prevents other particles from releasing (dissipating heat) from the fiber. It is presumed to play a role. Other particles are preferably organic particles and / or inorganic particles, for example. Examples of the organic particles include particles such as a styrene resin and an acrylic resin. Examples of inorganic particles include particles of titanium oxide, zirconium oxide, zirconium silicate, and the like.

  When the photothermal-convertible regenerated cellulose fiber is regenerated cellulose fiber by the viscose method, the other particles are preferably acid-resistant and / or alkali-resistant particles. For example, particles having resistance to a strong acid having a pH of 1 or less and / or a strong alkali atmosphere having a pH of 13 or more are preferable. Alternatively, the other particles are preferably particles that dissolve in viscose or do not form foreign matters in the viscose. Specifically, the acid resistance of other particles can be confirmed by adding about 1 to 3% by mass of particles to a 10% aqueous sulfuric acid solution and observing the state of the particles in the solution. Similarly, the alkali resistance of other particles can be confirmed in the same manner as acid resistance by adding about 1 to 3% by mass of particles to a 6% sodium hydroxide solution.

  In order to further enhance the effect of the present invention, it is preferable that the other particles are particles having heat dissipation prevention properties and / or low thermal conductivity. If such particles are contained in the fiber together with the photothermal conversion particles, it is presumed that the heat stored inside the fiber by the photothermal conversion particles is difficult to dissipate to the outside of the fiber due to the presence of other particles. In the case of particles having low thermal conductivity, particles having a thermal conductivity of 30 W / (m · K) or less are preferable.

  In order to further enhance the effect of the present invention, the other particles preferably have an average primary particle size of 1 μm or less, more preferably an average secondary particle size of 1 μm or less, and even more preferably an average secondary particle size. The secondary particle size is 0.5 μm or less. Alternatively, the other particles are preferably 30% or more of particles having a primary particle size of 0.7 μm or less, more preferably 30% or more of particles having a secondary particle size of 0.7 μm or less, and even more. Preferably, particles having a secondary particle diameter of 0.4 μm or less are 30% or more. When other particles having a particle size within the above range are included in the fiber together with the photothermal conversion particles, the heat stored inside the fiber by the photothermal conversion particles is difficult to dissipate to the outside of the fiber due to the presence of the other particles. Presumed. The primary particle size and average primary particle size (50% particle size) of the other particles can be measured by electron micrograph. The secondary particle diameter and average secondary particle diameter (50% particle diameter) of the other particles can be measured by a laser diffraction light scattering method.

  Moreover, from the viewpoint of achieving both heat storage and fiber strength, the content of other particles in the photothermal-convertible regenerated cellulose fiber is preferably 0.5 to 15% by mass, more preferably 1 to 10% by mass, and still more preferably. Is 1 to 5% by mass, particularly preferably 1 to 3% by mass.

  When using a photothermal conversion particle | grain and another particle together, it is preferable that the mixing rate is 20-80 mass% of photothermal conversion particles and 20-80 mass% of other particles with respect to the whole mass of particle | grains. More preferably, it is 25-70 mass% of photothermal conversion particles, and 30-75 mass% of other particles. By making the mixing ratio within the above range, the fiber strength can be withstood practically while imparting the photothermal conversion function to the fiber, and the photothermal conversion particles are present alone in the fiber by other particles. The heat storage effect can be further enhanced than the case.

  The photothermal conversion regenerated cellulose fiber of the present invention may further contain a functional agent such as an ultraviolet absorber.

  Next, the manufacturing method of the photothermal conversion regenerated cellulose fiber of this invention is demonstrated. A known regenerated cellulose production method can be used as a method for incorporating regenerated cellulose into photothermal conversion particles satisfying the predetermined BET specific surface area and powder resistance. For example, in the case of viscose rayon, an aqueous dispersion of photothermal conversion particles is prepared, and the aqueous dispersion is mixed with a viscose stock solution containing cellulose to prepare a spinning viscose liquid. The coarse liquid is extruded from a nozzle, spun, and coagulated and regenerated, whereby the photothermal conversion particles can be present in the regenerated cellulose fiber in a finely dispersed state. Further, an aqueous dispersion containing photothermal conversion particles and other particles is prepared, and the aqueous dispersion is mixed with a viscose stock solution containing cellulose to prepare a spinning viscose liquid, and the spinning viscose liquid is prepared. Is extruded from a nozzle, spun, and coagulated and regenerated, whereby the photothermal conversion particles and other particles can be present in the regenerated cellulose fiber in a finely dispersed state.

  As the viscose stock solution containing cellulose, a viscose stock solution containing 7 to 10% by mass of cellulose, 5 to 8% by mass of sodium hydroxide, and 2 to 3.5% by mass of carbon disulfide may be prepared and used. At this time, additives such as ethylenediaminetetraacetic acid (EDTA) and titanium dioxide can be used as necessary. A viscose solution for spinning is prepared by mixing an aqueous dispersion containing the photothermal conversion particles or an aqueous dispersion containing photothermal conversion particles and other particles into the prepared viscose stock solution containing cellulose. The temperature of the spinning viscose liquid is preferably maintained at 19 to 23 ° C. In the spinning viscose liquid, when the photothermal conversion particles are contained alone, the addition amount of the photothermal conversion particles is preferably 1 to 15% by mass with respect to cellulose, and 1.5 to 15% by mass. More preferably, it is 2-10 mass%. In the spinning viscose liquid, when the photothermal conversion particles and other particles are used in combination, the addition amount of the photothermal conversion particles is preferably 0.5 to 10% by mass with respect to cellulose. It is more preferably 1 to 8% by mass, and further preferably 1.5 to 5% by mass. In the spinning viscose liquid, the amount of the other particles added is preferably 0.5 to 15% by mass, more preferably 1 to 10% by mass, and 1 to 5% with respect to cellulose. It is more preferable that it is mass%, and it is especially preferable that it is 1-3 mass%. The mixing ratio of the photothermal conversion particles and other particles is preferably 20 to 80% by mass of the photothermal conversion particles and 20 to 80% by mass of the other particles with respect to the total mass of the particles. More preferably, it is 25-70 mass% of photothermal conversion particles, and 30-75 mass% of other particles.

  As the spinning bath (Mueller bath), it is preferable to use a spinning bath containing 95 to 130 g / liter of sulfuric acid, 10 to 17 g / liter of zinc sulfate, and 290 to 370 g / liter of sodium sulfate. A more preferable sulfuric acid concentration is 100 to 120 g / liter. The spinning bath preferably has a temperature of 45 to 60 ° C. As spinning conditions, the regenerated cellulose fiber (rayon fiber) of the present invention can be produced using a normal circular nozzle. A variant nozzle can also be used. The selection of the spinning nozzle depends on the target production amount, but preferably has a circular nozzle having a diameter of 0.05 to 0.12 mm and 1000 to 20000 holes.

  Using the spinning nozzle, the spinning viscose liquid obtained above is extruded into a spinning bath, spun, and coagulated and regenerated. The spinning speed is preferably in the range of 35 to 70 m / min. Further, the stretching ratio is preferably 39 to 50%. Here, the stretch ratio indicates how many percent the stretched length is increased when the stretched length is 100%. In terms of magnification, the ratio is 1 before stretching and 1.39 to 1.50 after stretching.

  The rayon fiber yarn obtained as described above is cut into a predetermined length and subjected to a scouring treatment. The scouring step is preferably performed in the order of hot water treatment, hydrosulfurization treatment, bleaching, pickling, and oil application.

  Thereafter, if necessary, excess oil agent and moisture are removed from the fiber by a method such as a compression roller or vacuum suction, and then a drying treatment is performed to obtain the rayon fiber of the present invention.

  The regenerated cellulose fiber of the present invention preferably has a fineness of 0.3 to 6.0 dtex. More preferably, it is 0.6-4.0 dtex, More preferably, it is 0.9-3.3 dtex. When the fineness is less than 0.3 dtex, the single fiber tends to be broken during stretching. If the fineness exceeds 6.0 dtex, there is a risk that it will not be suitable for clothing use. However, for interior products such as carpets, fibers having a fineness exceeding 6.0 dtex can be used.

  The regenerated cellulose fiber of the present invention is provided in the form of long fibers (for example, tow, filament, non-woven fabric, etc.), short fibers (for example, raw cotton for wet papermaking, raw cotton for airlaid non-woven fabric, raw cotton for cards, etc.) It is preferable to form a structure. As the fiber structure, for example, tow, filament, spun yarn, batting (padded cotton), paper, non-woven fabric, and woven / knitted fabric are preferable. In the fiber structure of the present invention, the heat-convertible particles are contained in the regenerated cellulose fiber, but the texture is good. In the fiber structure of the present invention, when used in combination with other fibers, the regenerated cellulose fiber is preferably contained in an amount of 5% by mass or more based on the total mass of the fiber structure. More preferably, it is 10 mass% or more. Moreover, in the use which considers hues, such as clothing, when using together with another fiber, it is preferable that content of the said regenerated cellulose fiber is 50 mass% or less with respect to the whole fiber structure mass, and is 30 mass% or less. More preferably, it is 20% by mass or less.

  As the fiber structure of the present invention, for example, when a spun yarn is used, the regenerated cellulose fiber alone or other regenerated cellulose fibers, cotton, hemp, wool, acrylic, polyester, polyamide, polyolefin, polyurethane and other fibers It is preferable to blend and combine. Such spun yarn can be processed into a woven or knitted fabric and used for clothing or the like. In particular, as a preferable combination with other fibers, for example, in exothermic clothing, 50 to 5% by mass of the regenerated cellulose fiber of the present invention and cotton, hemp, wool, acrylic, polyethylene terephthalate (PET), polytrimethylene terephthalate ( Polyester such as PTT), polyamide such as nylon 6, polyolefin such as polypropylene, and at least one other fiber such as polyurethane can be used. In particular, acrylic fibers and / or cotton fibers may be mixed and used.

  As the fiber structure of the present invention, for example, in the case of a non-woven fabric, the regenerated cellulose fiber alone or other regenerated cellulose fibers, cotton, hemp, wool, acrylic, polyester, polyamide, polyolefin, polyurethane, and other fibers are mixed. Can be used. Examples of the form of the nonwoven fabric include a wet nonwoven fabric (wet papermaking), an airlaid nonwoven fabric, a hydroentangled nonwoven fabric, and a needle punched nonwoven fabric.

  Hereinafter, it demonstrates using drawing. FIG. 1 is an optical micrograph (magnification 640 times) showing a cross section of a photothermal conversion rayon fiber (fiber A) in one example of the present invention. FIG. 13 is an optical micrograph (magnification 320 times) showing the side surface of the photothermal conversion rayon fiber (fiber I) in one example of the present invention. FIG. 14 is an optical micrograph (magnification 320 times) showing the side surface of the photothermal conversion rayon fiber (fiber J) in one example of the present invention. 1, 13, and 14 show that the photothermal conversion particles are finely dispersed almost uniformly in cellulose.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited to the following examples. In addition, when the addition amount is simply expressed as% in the following examples, it means mass%.

(Measuring method)
(1) Specific surface area It measured according to the BET specific surface area method prescribed | regulated by JISR1626.

(2) Average primary particle size, average secondary particle size Particles (ATO particles) doped with antimony in the tin oxide of (1) provided in the aqueous dispersion are 50% particle size by laser diffraction light scattering method. (Average secondary particle diameter) was measured. For measurement of the average secondary particle diameter, a laser diffraction / scattering particle distribution measuring apparatus “LA-950S2” manufactured by Horiba, Ltd. was used. The 50% particle size (average secondary particle size) of other particles was measured in the same manner.
Particles (Ti / ATO particles) obtained by coating antimony-doped tin oxide on titanium oxide (2) provided as dry particles were measured for 50% particle size (average primary particle size) by electron micrograph. The 50% particle size (average primary particle size) of other particles was measured in the same manner.

(3) Powder resistance The electrical resistance value (Ωcm) of the green compact obtained by pressing the powder at 9.807 MPa was measured.

(4) Hue of the fiber The whiteness of the fiber is measured three times using MINOLTA “CR310” conforming to the diffuse illumination vertical light receiving system defined in JIS Z 8722. The measurement was performed according to “L ^* a ^* b ^* color system” defined in JIS Z 8729.
Hunter whiteness was calculated from the L ^* value, a ^* value, and b ^* value, and was calculated using the following equation.
Hunter whiteness: W (whiteness) = 100-√ [(100-L ^* ) + (a ^{* 2} + b ^{* 2} )]
Raw cotton hunters with whiteness of 80 or more were designated as A, less than 80 and 60 or more as B, and less than 60 as C.

(5) Physical properties of fibers The fineness and wet / dry strength were measured by tests according to JIS L 1015.

(6) Elemental analysis of fiber Elemental analysis of the fiber was performed using an ICP emission analyzer (manufactured by Shimadzu Corporation, product name “ICPS-7510”).

(7) Element content measurement of fiber The element content of the fiber was measured using fluorescent X-ray analysis. The fluorescent X-ray analysis was measured by theoretical calculation by the FP method using a fluorescent X-ray analyzer “LAB CENTER XRF-1700” manufactured by Shimadzu Corporation. The outline of this measuring apparatus and the measurement conditions were as follows.
(I) Outline of measuring device Measuring element range: 4Be to 92U
X-ray tube 4kw thin window, Rh target Spectrometer LiF, PET, Ge, TAP, SX
Primary X-ray filter 4 types automatic exchange (Al, Ti, Ni, Zr)
Field-restricting diaphragm Five types of automatic replacement (diameter 1, 3, 10, 20, 30mmφ)
Detector Scintillation counter (heavy element), proportional counter (light element)
(Ii) Measurement conditions Tube voltage-tube current 40 kW-95 mA
(Iii) Measurement sample A fiber cut fiber was used as a measurement sample. The irradiation surface was adjusted to have a diameter of 10 mm and a thickness of several mm, irradiated from above and transmitted downward.

(8) Thermal storage test Thermal storage was measured with the test apparatus shown in FIG. A non-woven fabric sample having a predetermined basis weight was used as a heat storage measurement sample, and the temperature difference from the case of using Comparative Example 1 (regular rayon) was measured and evaluated according to the following criteria.
A 5 ° C or higher B 2 ° C or higher and lower than 5 ° C C lower than 2 ° C

  FIG. 2 is an explanatory view showing a heat storage test method in one embodiment of the present invention. This test equipment is located in the Japan Chemical Fiber Inspection Association. A flat plate 2, a thermometer 3, and a sample 4 were placed on the polystyrene foam sample stage 1, and the sample was placed flat with a sample holder 5. A spotlight was irradiated from an irradiation lamp 6 (manufactured by Iwasaki Electric Co., Ltd., trade name “eye lamp”, PRS100V, 500 W) at a height of L = 50 cm from the upper surface of the sample stage 1. The irradiation time was 20 minutes, the cooling time was 20 minutes, and the test room temperature was 20 ° C. ± 2 ° C.

(9) Antistatic test [friction band voltage]
A friction voltage test (friction cloth: hair, warp) according to JIS L 1094-2008 was performed in an atmosphere of 20 ° C. and 40% RH. A non-woven fabric sample (approx. 100 g / m ² ) was used as a measurement sample.
A sample in which the frictional voltage test result was lower than that in Comparative Example 1 (regular rayon) was marked with ◯, and a sample with the same or higher value than regular rayon was marked with ×.
[Surface leakage resistance]
According to the reference method of JIS L 1094-2008, the measurement was performed in an atmosphere of an applied voltage of 1000 V, 20 ° C., and 40% RH. A non-woven fabric sample (approx. 110 g / m ² ) was used as a measurement sample.

(10) Light transmittance and reflectance measurement The average reflectance and average transmittance of visible light and near infrared rays were measured. The equipment used was a “V-570 spectral altimeter ISN-470 type integrating sphere” manufactured by JASCO Corporation, and the wavelength ranges were 380 nm to 780 nm for visible light and 780 nm to 2100 nm for near infrared. A non-woven fabric sample (weight per unit area: 60 g / m ² ) was used as a measurement sample.

(Examples 1-4, Comparative Examples 1 and 2)
(1) Fiber A
[Viscose undiluted solution conditions]
Transparent conductive water dispersion manufactured by Ishihara Sangyo Co., Ltd. [Product name “SN-100D”, aqueous dispersion of fine particles of SnO ₂ / Sb doped tin oxide (SnO ₂ / Sb dope) with an ATO particle concentration of 30% by mass] 67 An aqueous dispersion was prepared by mixing a mixed solution composed of mass% and the balance water with a desktop homomixer (trade name “TKMHOMOMIXER MARKII” manufactured by PRIMIX Co., Ltd.). The aqueous dispersion was added to the raw material viscose so that the mass of ATO particles was 2% by mass with respect to cellulose, and the mixture was stirred and mixed in a mixer. The raw material viscose used contained cellulose content of 9.0% by mass, sodium hydroxide content of 5.2% by mass, and carbon disulfide containing 32% by mass with respect to cellulose. In “SN-100D”, the specific surface area of ATO particles was 83.9 m ² / g, the average secondary particle diameter was 0.109 μm, and the powder resistance was 4.0 Ωcm.
[Spinning conditions]
The obtained viscose for spinning was spun at a spinning speed of 50 m / min and a draw ratio of 44% by a two-bath tension spinning method to obtain a fiber having a fineness of 1.4 dtex. As the first bath (spinning bath), a Mueller bath (50 ° C.) containing 115 g / L of sulfuric acid, 13 g / L of zinc sulfate, and 350 g / L of sodium sulfate was used. A nozzle having 10692 holes having a hole diameter of 0.06 mm was used as a spinneret for discharging viscose. During spinning, there was no inconvenience such as single yarn breakage, and the spinnability of the mixed viscose was good.
[Scouring conditions]
The viscose rayon yarn thus obtained was cut into 38 mm and subjected to a scouring treatment. In the scouring step, washing with water was performed after the hot water treatment, and then excess moisture was removed from the fibers with a compression roller, followed by treatment with sodium hydrosulfide. After washing with water, the moisture was removed with a compression roller. Next, after treatment with sodium hypochlorite, treatment with sulfuric acid, washing with water, dropping moisture with a compression roller, treating with oil agent, dropping moisture with a compression roller, and drying treatment (60 ° C., 7 hours) Thus, fiber A (Example 1) was obtained. When the fiber A was analyzed, Sb was 523 ppm and Sn was 3990 ppm according to elemental analysis with an ICP (high frequency plasma) emission spectrometer, and Sb was 0.00 according to element content measurement with a fluorescent X-ray analyzer. 03 mass% and Sn were 0.29 mass%.

(2) Fiber B
As an additive liquid, transparent conductive water dispersion “SN-100D” manufactured by Ishihara Sangyo Co., Ltd. (a concentration of 30% by mass of ATO particles) 11.1% by mass and titanium oxide manufactured by Sakai Chemical Industry Co., Ltd. (product name “SA-14”) , Average secondary particle size 0.3 μm) 13.3 mass%, and the remaining liquid mixture is mixed with a desktop homomixer (“TK MHOMOMIXER MARKII” manufactured by PRIMIX Corporation) Prepared. The aqueous dispersion is added to the raw material viscose so that the total mass of ATO particles and titanium oxide particles is 10% by mass with respect to cellulose (2% by mass of ATO particles, 8% by mass of titanium oxide particles). The mixture was stirred. Except for the fineness of 1.7 dtex, spinning, scouring, and drying were performed in the same manner as in Example 1 to obtain Fiber B (Example 2).

(3) Fiber C
As an additive solution, manufactured by Ishihara Sangyo Kaisha, Ltd. of white conductive titanium oxide [trade name "ET-500 W", particles coated with antimony-doped tin oxide titanium oxide (Ti0 _2, Sn0 ₂ / Sb-doped), Ti / ATO particles] A mixed liquid composed of 20% by mass and the balance water was mixed with a desktop homomixer (“TK MHOMOMIXER MARKII” manufactured by PRIMIX Co., Ltd.) to prepare an aqueous dispersion. The aqueous dispersion was added to the raw material viscose so that the mass of Ti / ATO particles was 10% by mass with respect to cellulose, and the mixture was stirred and mixed with a mixer. Except for changing the fineness to 1.7 dtex, spinning, scouring, and drying were performed in the same manner as in Example 1 to obtain a fiber C (Example 3). In “ET-500W”, the average primary particle diameter of Ti / ATO particles was 0.254 μm, and the powder resistance was 3.5 Ωcm.

(4) Fiber D
As an additive solution, manufactured by Ishihara Sangyo Kaisha, Ltd. of white conductive titanium oxide {trade name "ET-300 W", particles coated with antimony-doped tin oxide titanium oxide (Ti0 _2, Sn0 ₂ / Sb-doped), Ti / ATO particles} A mixed liquid composed of 20% by mass and the balance water was mixed with a desktop homomixer (“TK MHOMOMIXER MARKII” manufactured by PRIMIX Co., Ltd.) to prepare an aqueous dispersion. The aqueous dispersion was added to the raw material viscose so that the mass of Ti / ATO particles was 10% by mass with respect to cellulose, and the mixture was stirred and mixed with a mixer. Except for changing the fineness to 1.7 dtex, spinning, scouring, and drying were performed in the same manner as in Example 1 to obtain a fiber D (Example 4). In “ET-300W”, the average primary particle diameter of Ti / ATO particles was 0.038 μm, and the powder resistance was 20 Ωcm.

(5) Fiber E
The fiber E (Comparative Example 1) was obtained in the same manner as in Example 1 until spinning, scouring, and drying without adding anything to the raw material viscose.

(6) Fiber F
Except for the white conductive titanium oxide “ET-500W” manufactured by Ishihara Sangyo Co., Ltd., the black powder of zirconium carbide (ZrC) shown in Table 2 was added and the fineness was set to 1.7 dtex, in the same manner as in Example 3. Fiber F (Comparative Example 2) was obtained.

(Example 5)
As an additive liquid, a transparent conductive water dispersion “SN-100D” (concentration of ATO particles: 30% by mass) of 67% by mass made by Ishihara Sangyo Kaisha Ltd. , Trade name “TKMHOMOMIXER MARKII”) to prepare an aqueous dispersion. The aqueous dispersion was added to the raw material viscose so that the mass of ATO particles was 1% by mass with respect to cellulose, and the mixture was stirred and mixed in a mixer. Spinning, scouring, and drying were performed in the same manner as in Example 1 to obtain fiber G.

(Example 6)
As an additive liquid, a transparent conductive water dispersion “SN-100D” (concentration of ATO particles: 30% by mass) of 67% by mass made by Ishihara Sangyo Kaisha Ltd. , Trade name “TKMHOMOMIXER MARKII”) to prepare an aqueous dispersion. The aqueous dispersion was added to the raw material viscose so that the mass of ATO particles was 5% by mass with respect to cellulose, and the mixture was stirred and mixed with a mixer. Spinning, scouring, and drying were performed in the same manner as in Example 1 to obtain fiber H.

(Example 7)
As an additive liquid, transparent conductive water dispersion “SN-100D” (concentration of ATO particles: 30% by mass) manufactured by Ishihara Sangyo Co., Ltd., and 7.6% by mass of titanium oxide “SA-14” manufactured by Sakai Chemical Industry Co., Ltd. Then, the remaining mixture of water was mixed with a desktop homomixer (“TKMMOMOMIXER MARKII” manufactured by PRIMIX Co., Ltd.) to prepare an aqueous dispersion. The aqueous dispersion was added to the raw material viscose so that the total mass of ATO particles and titanium oxide particles was 3.8% by mass (2% by mass of ATO particles, 1.8% by mass of titanium oxide particles) with respect to cellulose. The mixture was stirred and mixed in a mixer. Spinning, scouring, and drying were performed in the same manner as in Example 1 to obtain Fiber I.

(Example 8)
As an additive liquid, transparent conductive water dispersion “SN-100D” manufactured by Ishihara Sangyo Co., Ltd., 28 mass% (concentration of ATO particles 30 mass%), zirconium silicate (product name “Micropax S” manufactured by Hakusui Tech Co., Ltd., average A mixed liquid composed of 7.6% by mass (primary particle size 0.8 μm) and the balance water was mixed with a desktop homomixer (“TK MHOMOMIXER MARKII” manufactured by PRIMIX Co., Ltd.) to prepare an aqueous dispersion. The aqueous dispersion is used as raw material viscose so that the total mass of ATO particles and zirconium silicate particles is 3.8% by mass (2% by mass of ATO particles and 1.8% by mass of zirconium silicate particles) based on cellulose. The mixture was added and stirred and mixed in a mixer. Spinning, scouring, and drying were performed in the same manner as in Example 1 to obtain fiber J.

(Comparative Example 3)
As an additive solution, a mixed solution composed of 20% by mass of titanium oxide “SA-14” manufactured by Sakai Chemical Industry and the balance water is mixed with a desktop homomixer (“TK MHOMOMIXER MARKII” manufactured by Primix Co., Ltd.) to form water. A dispersion was prepared. The aqueous dispersion was added to the raw material viscose so that the mass of the titanium oxide particles was 1.8% by mass with respect to cellulose, and the mixture was stirred and mixed in a mixer. Spinning, scouring, and drying were performed in the same manner as in Example 1 to obtain fiber K.

(Comparative Example 4)
As an additive liquid, a mixed liquid composed of 20% by mass of zirconium silicate “Micropax S” manufactured by Hux Itec Co., Ltd. and the balance water is mixed with a desktop homomixer (“TK MHOMOMIXER MARKII” manufactured by Primix Co., Ltd.) and dispersed in water. A liquid was prepared. The aqueous dispersion was added to the raw material viscose so that the mass of the zirconium silicate particles was 10% by mass with respect to cellulose, and the mixture was stirred and mixed in a mixer. Spinning, scouring, and drying were performed in the same manner as in Example 1 except that the fineness was 1.7 dtex, and a fiber L was obtained.

  The physical properties, hue, and elemental analysis of the fibers of Examples and Comparative Examples were performed, and the results are shown in Tables 2 and 3 below. Tables 2 and 3 also show the physical properties of the photothermal conversion particles and other particles contained in each fiber.

<Production of non-woven fabric>
A card web is prepared by blending 65% by mass of acrylic fiber (Toray “Sylworm”, fineness 1.1 dtex, fiber length 38 mm) and 35% by mass of any of the fibers A to F (rayon fibers) obtained above. did. Next, a columnar water flow is injected at a water pressure of 3 MPa from a nozzle arranged at a hole diameter of 0.13 mmφ and a hole pitch of 1 mm on one side of the card web, and a columnar water flow is injected again at a water pressure of 5 MPa on the same surface. Then, it was turned over and a columnar water flow was jetted at a water pressure of 5 MPa to produce a hydroentangled nonwoven fabric (35% by mass of rayon fiber) with a basis weight shown in Table 1 below. Moreover, it is the same method as the above except that the fibers A to E and the fibers G to L obtained above are used, the structure of the fibers is 100% by weight of rayon fibers, and the basis weight of the nonwoven fabric is about 100 g / m ^2. A hydroentangled nonwoven fabric (rayon fiber 100% by mass) was produced.

  The obtained hydroentangled nonwoven fabric was measured for heat storage, antistatic properties (friction band voltage, surface leakage resistance), visible light transmittance, near infrared reflectance, and near infrared transmittance. The results are shown in Tables 1 to 3 below. In addition, the heat storage data shown in Table 1 below was data using a nonwoven fabric containing 35% by weight of rayon fibers. In the following Tables 1 to 3, “-” means not measured.

  As shown in Tables 1 to 3, the fibers of the examples of the present invention have a high photothermal conversion function, good antistatic properties, and properties such as color tone and texture hardly change from ordinary rayon fibers. It was confirmed that it was a regenerated cellulose fiber.

  1 shows an optical micrograph (magnification 640 times) of a cross section of the fiber (fiber A) of Example 1, and FIGS. 13 and 14 show the fiber (fiber I) and Example of Example 7, respectively. The optical microscope photograph (magnification 320 times) of the side surface of 8 fibers (fiber J) was shown. From FIG. 1, it was confirmed that the photothermal conversion particles were finely dispersed almost uniformly in cellulose. Moreover, from FIG.13 and FIG.14, it has confirmed that the photothermal conversion particle | grains and other particle | grains were disperse | distributed substantially uniformly in the cellulose.

  In FIG. 9, the result of the near-infrared absorptance in Example 1 (fiber A), Example 3 (fiber C), and Comparative example 1 (fiber E) of this invention was shown. As can be seen from FIG. 9, the fiber of the example of the present invention had a higher near-infrared absorptance than the regular rayon fiber (fiber E of Comparative Example 1).

  In FIG. 10, the result of the thermal storage test in Example 1 (fiber A), Example 5 (fiber G), Example 6 (fiber H), and Comparative example 1 (fiber E) of this invention was shown. As can be seen from Tables 2 to 3 and FIG. 10, the higher the content of the photothermal conversion particles in the photothermal conversion particles, the higher the temperature rise and the better the heat storage property. In addition, the result of the thermal storage test of FIG. 10 was a result using the nonwoven fabric of 100 mass% of rayon fibers. Hereinafter, similarly, FIGS. 11 to 12 show the results of a heat storage test using a non-woven fabric of 100% by weight of rayon fiber.

  FIG. 11 shows heat storage properties in Example 1 (fiber A), Example 2 (fiber B), Example 7 (fiber I), Comparative example 1 (fiber E), and Comparative example 3 (fiber K) of the present invention. The results of the test are shown. In FIG. 12, the result of the thermal storage test in Example 1 (fiber A), Example 8 (fiber J), Comparative example 1 (fiber E), and Comparative example 4 (fiber L) of this invention was shown. As can be seen from Tables 2 to 3 and FIGS. 11 to 12, the inclusion of other particles in addition to the photothermal conversion particles has a synergistic effect and is more excellent in heat storage. Moreover, it turned out that the direction which uses a titanium oxide as another particle | grain is more excellent in a synergistic effect.

Example 9
<Experiment 1>
35% by mass of the fiber A (rayon fiber) of Example 1 and 65% by mass of acrylic fiber (“Sylwarm” manufactured by Toray, fineness 1.1 dtex, fiber length 38 mm) were mixed, and the mixed cotton nonwoven fabric was prepared as described above for the nonwoven fabric. (A basis weight of 150 g / m ² ) was produced. For comparison, the heat storage function was evaluated using a mixed cotton nonwoven fabric using regular rayon fiber (fiber E of Comparative Example 1) instead of the rayon fiber of this example. The results are shown in FIG. This example product showed a temperature increase of + 14.8 ° C. compared to the comparative example product.
<Experiment 2>
35% by mass of fiber A (rayon fiber) of Example 1 and 65% by mass of wood pulp were mixed and subjected to wet papermaking to prepare a paper product (weight per unit area: 80 g / m ² ). For comparison, the heat storage function was evaluated using a paper product using regular rayon fiber (fiber E of Comparative Example 1) instead of the rayon fiber of this example. The results are shown in FIG. This example product showed a temperature increase of + 11.4 ° C. compared to the comparative example product.
<Experiment 3>
The nonwoven fabric (100 g / m ² ) of 100% by mass of the fiber A (rayon fiber) of Example 1 was dyed with a reactive dye, and the heat storage function of the dyed product was evaluated. The results are shown in FIG. As for this Example goods, the temperature rise with a significant difference was recognized compared with the comparative example goods (fiber E).
<Experiment 4>
A non-woven fabric (100 g / m ² ) of 100% by mass of fiber A (rayon fiber) of Example 1 was dyed with a cationic dye, and the heat storage function of the dyed product was evaluated. The results are shown in FIG. The product of this example was found to have a significant temperature increase compared to the comparative product (Fiber E).
<Experiment 5>
The heat storage function was evaluated by subjecting 100% by mass of rayon fiber nonwoven fabric (fiber weight of 100% / m ² ) of Example 1 to a bleaching treatment and a washing test. The results are shown in FIG. The heat storage function did not change even after bleaching and washing tests. The bleaching treatment was performed for 50 minutes (80 to 90 ° C.) into a mixed bath (bath ratio 1:30) of sodium silicate (1 g / L), caustic soda (1 g / L), and hydrogen peroxide (1 g / L). The washing test was conducted under a condition of 120 minutes (60 ° C.) into a 3% sodium carbonate bath (bath ratio 1: 100).
<Experiment 6>
A mixed cotton nonwoven fabric (150 g / m ² ) was produced in the same manner as the nonwoven fabric described above except that the mixing ratio of the fiber A (rayon fiber) in Example 1 was changed as shown in FIG. For comparison, the heat storage function was evaluated using a mixed cotton nonwoven fabric using regular rayon fiber (fiber E of Comparative Example 1) instead of the rayon fiber of this example. The results are shown in FIG. This example product showed a temperature increase of + 2.7 ° C. to + 6.3 ° C. compared to the comparative example product.

  As described above, from the results of Experiments 1 to 6, it can be confirmed that the photothermal conversion rayon fiber of the present invention has high heat storage properties, and good performance can be obtained for dyeability and washing resistance. It was confirmed that it was useful for fiber structures such as knitted fabrics.

  The photothermal conversion regenerated cellulose fiber of the present invention can be used for fiber structures such as tow, filament, spun yarn, batting (padded cotton), paper, nonwoven fabric, woven and knitted fabric. The fiber structure of the present invention includes underwear, innerwear, outerwear, mufflers, stalls, hats, ear hooks, gloves and other clothing products, wallpaper, shoji paper, carpets, curtains and other interior products, blankets, and duvet covers. It is useful for bedding such as sheets and pillow covers.

1 Sample stand 2 Flat plate 3 Thermometer 4 Sample 5 Sample holder 6 Irradiation lamp

Claims (8)

Regenerated cellulose fiber containing photothermal conversion particles having heat ray absorption ability in the fiber,
The photothermal conversion regenerated cellulose fiber, wherein the photothermal conversion particles include particles having a BET specific surface area of 5 to 120 m ² / g and a powder resistance of less than 30 Ωcm in a dispersed state.   The photothermal-convertible regenerated cellulose fiber according to claim 1, wherein the photothermal-convertible regenerated cellulose fiber is present in an amount of 1 to 15% by mass in the photothermal-convertible regenerated cellulose fiber.   The photothermal-convertible regenerated cellulose fiber according to claim 1 or 2, wherein the product of the specific surface area of the photothermal-convertible particle and the content of the photothermal-convertible particle in the fiber is in the range of 0.5 to 3.5. The photothermal-convertible regenerated cellulose fiber according to any one of claims 1 to 3, wherein the photothermal-convertible particle is at least one particle selected from the following (1) and (2).
(1) Fine particles obtained by doping tin oxide with antimony (Sn0 ₂ / Sb dope).
(2) fine particles coated with antimony-doped tin oxide titanium oxide (Ti0 _2, Sn0 ₂ / Sb-doped). Near-infrared transmittance is 20% or less, near-infrared reflectance is 40% or less, and visible light transmittance is 100% by mass of hydrothermally entangled nonwoven fabric (60 g / m ² per unit area) of the raw photothermal-convertible cellulose fiber. It is 20% or more, The photothermal conversion regenerated cellulose fiber of any one of Claims 1-4.   The photothermal-convertible regenerated cellulose fiber according to any one of claims 1 to 5, comprising other particles in addition to the photothermal-convertible particles.   The fiber structure containing the photothermal conversion regenerated cellulose fiber of any one of Claims 1-6. It is a manufacturing method of photothermal conversion regenerated cellulose fiber given in any 1 paragraph of Claims 1-6,
Preparing an aqueous dispersion of photothermal conversion particles having a BET specific surface area in the range of 5 to 120 m ² / g and a powder resistance of less than 30 Ωcm;
The viscose stock solution containing cellulose is mixed with the aqueous dispersion to prepare a viscose solution for spinning,
A method for producing a photothermal-convertible regenerated cellulose fiber, wherein the spinning viscose liquid is extruded from a nozzle, spun, and coagulated and regenerated.