JP7285633B2 - Photothermal conversion resin composition and fiber containing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a photothermal conversion resin composition and fibers containing the same.

Photothermal conversion substances that absorb infrared rays and convert them into heat are known. A fiber containing a photothermal conversion substance can provide excellent cold protection by converting sunlight into heat.

As such fibers, for example, Patent Document 1 discloses regenerated cellulose fibers containing particles of tin oxide doped with antimony (“ATO particles”). Patent document 1 also discloses a regenerated cellulose fiber that further contains titanium oxide to prevent heat dissipation.

Patent Document 2 discloses a fiber containing tungsten oxide-based photothermal conversion particles.

Patent Document 3 discloses a method for producing tungsten-based oxide particles.

JP 2013-147785 A JP-A-2006-132042 JP 2005-187323 A

An object of the present invention is to provide a light-to-heat convertible resin composition capable of imparting high light-to-heat convertibility with a small amount of light-to-heat convertible particles, and a fiber containing the same.

The inventors have found that the above problems can be solved by the present invention having the following aspects.
<<Aspect 1>>
a thermoplastic resin, and tungsten oxide-based light-to-heat converting particles and heat-retaining particles dispersed in the thermoplastic resin, wherein the light-to-heat converting particles are 0.01 to less than 0.50% by mass; and the heat-retaining particles are 0.01 to 70% by mass or less, and the photothermal conversion resin composition.
<<Aspect 2>>
The photothermal convertible resin composition according to aspect 1, wherein the photothermal convertible particles are selected from:
General formula (1): M _x W _y O _z {wherein M is H, He, an alkali metal element, an alkaline earth metal element, a rare earth element, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, one or more elements selected from the group consisting of Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I, where W is tungsten and O is oxygen; , x, y and z are positive numbers, 0<x/y≦1, and 2.2≦z/y≦3.0}. Or general formula (2): W _y O _z {wherein W is tungsten, O is oxygen, y and z are each positive numbers, and 2.45≦z/y≦2.999 is}, tungsten oxide particles having a Magneli phase.
<<Aspect 3>>
3. The photothermal conversion resin composition according to aspect 1 or 2, wherein the photothermal conversion particles have a volume average particle size of 1 nm or more and 800 nm or less.
<<Aspect 4>>
4. The photothermal conversion resin composition according to any one of aspects 1 to 3, wherein the heat insulating particles are inorganic oxide particles.
<<Aspect 5>>
5. The photothermal conversion resin composition according to any one of aspects 1 to 4, wherein the heat-retaining particles have an average primary particle size of 10 nm or more and 5 μm or less.
<<Aspect 6>>
The thermoplastic resin is a polyolefin resin, polystyrene resin, polyester resin, acrylic resin, polyamide resin, polyvinyl alcohol resin, polyurethane resin, polycarbonate resin, polysulfone resin, derivatives thereof, and mixtures thereof. The photothermal conversion resin composition according to any one of aspects 1 to 5, which is selected from the group consisting of:
<<Aspect 7>>
A photothermal conversion film comprising the photothermal conversion resin composition according to any one of aspects 1 to 6.
<<Aspect 8>>
A photothermal conversion fiber comprising the photothermal conversion resin composition according to any one of aspects 1 to 6.

FIG. 1 shows temperature profiles during lamp irradiation in Comparative Examples 1 and 2 and Example 1. FIG.

<<Photothermal conversion resin composition>>
The photothermal conversion resin composition of the present invention comprises a thermoplastic resin, and tungsten oxide-based photothermal conversion particles and heat insulating particles dispersed in the thermoplastic resin. It is less than 0.50% by mass, and the heat insulating particles are 0.01 to 70% by mass or less.

Patent Document 1 discloses that the photothermal conversion particles are used in an amount of 0.5% by mass or more, and that the photothermal conversion particles can be used in combination with other particles. Further, in Patent Document 2, although it is possible to use tungsten oxide-based photothermal conversion particles in an amount of 0.001% by mass to 80% by mass, it is possible to use the photothermal conversion particles in combination with other particles. is not suggested, and the fibers specifically disclosed contain 15% to 50% by weight of tungsten oxide-based light-to-heat converting particles.

The present inventors have found that only when tungsten oxide-based particles are used as light-to-heat converting particles in a small amount of less than 0.5% by mass, and when used in combination with heat-retaining particles, high light-to-heat conversion properties can be obtained. Found it. Although not bound by theory, it is believed that the light-to-heat conversion particles and heat-retaining particles are in a good dispersion state for light-to-heat conversion.

<Photothermal conversion particles>
The photothermal conversion particles used in the present invention are particles based on tungsten oxide. According to the studies of the present inventors, when other types of particles are used as photothermal conversion particles, high photothermal conversion due to a synergistic effect cannot be obtained even when used in combination with heat-retaining particles. On the other hand, in the case of using tungsten oxide-based particles, it was possible to obtain an advantageous effect by using them together with heat-retaining particles.

The tungsten oxide particles are not particularly limited as long as they have photothermal conversion properties. For example, tungsten oxide particles as disclosed in Patent Document 2 can be mentioned as such tungsten oxide particles.

For example, as photothermal conversion particles,
General formula (1): M _x W _y O _z {wherein M is H, He, an alkali metal element, an alkaline earth metal element, a rare earth element, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, one or more elements selected from the group consisting of Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I, where W is tungsten and O is oxygen; , x, y and z are positive numbers, 0<x/y≦1, and 2.2≦z/y≦3.0}. Or general formula (2): W _y O _z {wherein W is tungsten, O is oxygen, y and z are each positive numbers, and 2.45≦z/y≦2.999 It may be tungsten oxide particles having a Magneli phase represented by the following formula.

As a method for producing tungsten oxide-based particles, a method for producing a composite tungsten oxide or a tungsten oxide having a Magneli phase described in JP-A-2005-187323 can be used.

The element M is added to the composite tungsten oxide represented by the general formula (1). For this reason, including the case of z/y = 3.0 in general formula (1), free electrons are generated, and absorption characteristics derived from free electrons appear in the near-infrared light wavelength region. It is effective as a material that absorbs infrared rays and generates heat.

In particular, from the viewpoint of improving optical properties and weather resistance, the M element can be one or more of Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe and Sn. .

The particles of the composite tungsten oxide represented by the general formula (1) may be treated with a silane coupling agent to improve near-infrared absorption and transparency in the visible light wavelength region.

If the value of x/y, which indicates the amount of the element M to be added, is greater than 0, a sufficient amount of free electrons are generated and a sufficient near-infrared absorbing effect can be obtained. As the amount of the element M added increases, the amount of free electrons supplied increases and the near-infrared absorption effect also increases. The value of x/y may be 0.001 or more, 0.2 or more, or 0.30 or more, and may be 1.0 or less and 0.85 or less, 0.5 or less, or 0.35 or less. . The value of x/y can in particular be 0.33.

In the general formulas (1) and (2), the value of z/y indicates the level of oxygen content control. The composite tungsten oxide represented by the general formula (1) has a z/y value that satisfies the relationship of 2.2 ≤ z/y ≤ 3.0, so the tungsten oxide represented by the general formula (2) In addition to the same oxygen control mechanism as at work, there is a supply of free electrons due to the addition of element M even when z/y=3.0. In general formula (1), the value of z/y may satisfy the relationship of 2.45≤z/y≤3.0.

When the composite tungsten oxide represented by the general formula (1) has a hexagonal crystal structure or consists of a hexagonal crystal structure, the infrared-absorbing material fine particles transmit more light in the visible light wavelength region, In addition, the absorption in the near-infrared light wavelength region is increased. When cations of the element M are added to the voids of the hexagonal crystal, the transmission in the visible light wavelength region increases and the absorption in the near-infrared light wavelength region increases. Here, in general, hexagonal crystals are formed when an element M having a large ionic radius is added. Specifically, when an element having a large ionic radius such as Cs, K, Rb, Tl, In, Ba, Sn, Li, Ca, Sr, and Fe is added, hexagonal crystals are likely to be formed. However, the present invention is not limited to these elements, and elements other than these elements may be used as long as the additional element M is present in the hexagonal voids formed by ₆ units of WO.

When the composite tungsten oxide having a hexagonal crystal structure has a uniform crystal structure, the addition amount of the additive element M can be 0.2 or more and 0.5 or less as a value of x/y, It can be 0.30 or more and 0.35 or less, and particularly 0.33. It is considered that the additive element M is arranged in substantially all of the hexagonal voids when the value of x/y is 0.33.

In addition to the hexagonal crystal, tetragonal or cubic tungsten bronze also has a near-infrared absorption effect. Depending on these crystal structures, the absorption position in the near-infrared light wavelength region tends to change, and the absorption position tends to move to the longer wavelength side in the order of cubic < tetragonal < hexagonal. In addition, the absorption in the visible light wavelength region is small in the order of hexagonal < tetragonal < cubic. For this reason, hexagonal tungsten bronze may be used for applications that transmit more light in the visible light wavelength region and absorb more light in the near-infrared light wavelength region.

In the tungsten oxide having the Magneli phase represented by the general formula (2), the so-called "Magneli phase" having a composition ratio satisfying the relationship of 2.45 ≤ z/y ≤ 2.999 in which the value of z/y is Because of their high stability and high absorption characteristics in the near-infrared wavelength region, they are suitably used as photothermal conversion particles.

The dispersed particle size of the photothermal conversion particles can be selected depending on the purpose of use. First, in the case of application while maintaining transparency, it is preferable to have a dispersed particle diameter of 2000 nm or less in terms of volume average. This is because when the dispersed particle diameter is 2000 nm or less, the difference between the peak of the transmittance (reflectance) in the visible light wavelength region and the bottom of the absorption in the near-infrared light wavelength region increases, This is because the effect of light-to-heat conversion particles having transparency can be exhibited. Furthermore, particles with a dispersed particle size smaller than 2000 nm do not completely block light due to scattering, and can maintain visibility in the visible light wavelength region and at the same time efficiently maintain transparency.

Furthermore, when emphasizing transparency in the visible light wavelength region, it is preferable to consider scattering due to particles. Specifically, the volume average dispersed particle diameter of the photothermal conversion particles is preferably 800 nm or less, 500 nm or less, or 200 nm or less, and more preferably 100 nm or less, 50 nm or less, or 30 nm or less. When the dispersed particle size of the photothermal conversion particles is 200 nm or less, the geometric scattering or Mie scattering is reduced, resulting in a Rayleigh scattering region. In the Rayleigh scattering region, the scattered light is reduced in inverse proportion to the sixth power of the diameter of the dispersed particles. Therefore, as the diameter of the dispersed particles is reduced, the scattering is reduced and the transparency is improved. Furthermore, when the dispersed particle size is 100 nm or less, the scattered light is extremely small, which is preferable. From the viewpoint of avoiding light scattering, the smaller the dispersed particle size, the better. On the other hand, when the dispersed particle size is 1 nm or more, 3 nm or more, 5 nm or more, or 10 nm or more, industrial production tends to be easy. Here, the volume-average dispersed particle diameter of the photothermal conversion particles is obtained by irradiating the fine particles in Brownian motion with a laser beam and obtaining the particle diameter from the light scattering information obtained therefrom. It is measured using a meter (manufactured by Nikkiso Co., Ltd.).

The content of the photothermal conversion particles in the resin composition of the present invention is 0.01% by mass or more, 0.05% by mass or more, 0.10% by mass or more, 0.20% by mass or more, or 0.30% by mass. % or more, less than 0.5% by mass, 0.45% by mass or less, 0.40% by mass or less, 0.30% by mass or less, 0.20% by mass or less, or 0.10% by mass or less may be If the content of the photothermal conversion particles is within this range, the effect of using them together with the heat-retaining particles can be obtained, and the color tone of the resin composition is less likely to be affected. For example, the content of the photothermal conversion particles may be 0.05% by mass or more and 0.45% by mass or less, or 0.10% by mass or more and 0.40% by mass or less.

<Heat retaining particles>
The resin composition of the present invention contains heat insulating particles in an amount of 0.01 to 70% by mass or less. The type of heat-retaining particles is not particularly limited as long as the advantageous effects of the present invention can be obtained.

Examples of heat-retaining particles include organic fine particles and inorganic fine particles. Organic fine particles may include polymer fine particles.

Since the photothermal conversion particles used in combination absorb a large amount of light in the near-infrared wavelength region, the transmitted color tone may change from blue to green. It is preferred that the particles are white. From this point of view as well, inorganic oxide particles are preferable as the heat-retaining particles, and examples thereof include titanium oxide particles, silicon oxide particles, aluminum oxide particles, and zirconium oxide particles.

The average primary particle diameter of the heat insulating particles may be 10 nm or more, 30 nm or more, 50 nm or more, 100 nm or more, 300 nm or more, or 500 nm or more, and may be 5 μm or less, 1 μm or less, 800 nm or less, 500 nm or less, 300 nm or less, or 200 nm. or less, or 100 nm or less. The average primary particle size is a number average value measured using electron microscopy. The heat-retaining particles may have an average primary particle size of, for example, 10 nm to 5 μm, or 50 nm to 500 nm.

The content of the heat insulating particles in the resin composition of the present invention is 0.01% by mass or more, 0.05% by mass or more, 0.10% by mass or more, 0.50% by mass or more, and 1.0% by mass or more. , 3.0% by mass or more, 5.0% by mass or more, or 10% by mass or more, and 70% by mass or less, 60% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less , 10% by mass or less, 5.0% by mass or less, 3.0% by mass or less, 1.0% by mass or less, or 0.50% by mass or less. If the content of the heat-retaining particles is within such a range, the effect of using them together with the light-to-heat converting particles is likely to be obtained. For example, the content of the heat insulating particles may be 0.05% by mass or more and 40% by mass or less, or 0.10% by mass or more and 30% by mass or less.

<Thermoplastic resin>
In the resin composition of the present invention, light-to-heat converting particles and heat-retaining particles are dispersed in a thermoplastic resin. The type of such thermoplastic resin is not particularly limited as long as the advantageous effects of the present invention can be obtained.

Examples of thermoplastic resins include polystyrene resins, polyester resins, acrylic resins, polyamide resins, polyvinyl alcohol resins, polyurethane resins, polyolefin resins, polycarbonate resins, polysulfone resins, derivatives thereof, and their derivatives. mixtures.

The content of the thermoplastic resin in the resin composition of the present invention is 20% by mass or more, 40% by mass or more, 50% by mass or more, 60% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more. , or may be 98% by mass or more, 99.98% by mass or less, 99.8% by mass or less, 99.5% by mass or less, 99% by mass or less, 95% by mass or less, 90% by mass or less, 80% by mass % or less, 70 mass % or less, 60 mass % or less, or 50 mass % or less. For example, the content of the thermoplastic resin may be 50% by mass or more and 99.98% by mass or less, or 60% by mass or more and 99.98% by mass or less.

<Dispersant>
A dispersant may be contained in the resin composition of the present invention for the purpose of enhancing the dispersibility of the photothermal conversion particles in the thermoplastic resin. The dispersant may be used in the form of composite particles in which the surfaces of the photothermal conversion particles are coated with the dispersant, and in the form of composite particles in which the photothermal conversion particles are dispersed in the dispersant in the form of a resin. may be

Dispersants include compounds, especially resins, having functional groups such as amino groups, hydroxyl groups, carboxyl groups, and epoxy groups. These functional groups are adsorbed on the surface of the photothermal conversion particles and prevent the tungsten oxide particles from aggregating, thereby uniformly dispersing the photothermal conversion particles.

Dispersants as described in JP-A-2011-1551 may also be used, and examples of such dispersants include acrylic resins having hydroxyl groups and/or epoxy groups. From the viewpoint of heat resistance, the acrylic resin preferably has a thermal decomposition temperature of 230° C. or higher, preferably 250° C. or higher as measured by TG-DTA.

The content of the dispersant in the resin composition of the present invention is 0.01% by mass or more, 0.05% by mass or more, 0.1% by mass or more, 0.3% by mass or more, 0.5% by mass or more, 1.0% by mass or more, or 1.5% by mass or more, 10% by mass or less, 5.0% by mass or less, 3.0% by mass or less, 2.0% by mass or less, 1.5% by mass % or less, 1.0 mass % or less, or 0.5 mass % or less. For example, the content of the dispersant may be 0.1% by mass or more and 2.0% by mass or less, or 0.3% by mass or more and 1.5% by mass or less.

The ratio of the weight of the dispersant to the weight of the photothermal convertible particles (weight of dispersant/weight of photothermal convertible particles) is 1.0 or more, 2.0 or more, 3.0 or more, or 4.0 or more. 10 or less, 8.0 or less, 5.0 or less, 4.0 or less, 3.0 or less, 2.0 or less, or 1.0 or less. For example, the ratio may be between 1.0 and 5.0, or between 2.0 and 4.0.

<<Method for producing photothermal conversion resin composition>>
The photothermal conversion resin composition can be produced by kneading the photothermal conversion particles, the heat-retaining particles, and the thermoplastic resin. Optionally, the above dispersant can also be kneaded together. In this case, the photothermal conversion particles may be pre-coated with a dispersant.

Kneading can be performed using, for example, a kneader, a Banbury mixer, a Henschel mixer, a batch type kneader such as a mixing roll, and a continuous kneader such as a twin screw extruder or a single screw extruder. At this time, depending on the material used, the It can be kneaded at the following temperatures.

"the film"
A film containing the photothermal conversion resin composition of the present invention is obtained by forming a film from the resin composition obtained as described above. The method of forming the film is not particularly limited, but examples include a hot press method, a single-layer or multi-layer inflation method, a T-die method, and the like. Moreover, the film of the present invention may be produced by mixing a masterbatch containing each of the above components with other resins to obtain a light-to-heat conversion resin composition, which may be formed into a film.

That is, the film of the present invention contains the thermoplastic resin as described above, and the tungsten oxide-based light-to-heat converting particles and heat-retaining particles dispersed in the thermoplastic resin, and the light-to-heat converting particles are , 0.01 to less than 0.50% by mass, and the heat-retaining particles may be 0.01 to 70% by mass or less.

"fiber"
A fiber containing the photothermal conversion resin composition of the present invention can be obtained, for example, by melt-spinning the resin composition obtained as described above. In melt spinning, it is possible to use a generally used melt spinning apparatus. Moreover, the fiber of the present invention may be obtained by mixing a masterbatch containing each of the above components with another resin to obtain a light-to-heat conversion resin composition, which may be melt-spun.

That is, the fiber of the present invention contains the thermoplastic resin as described above, and the tungsten oxide-based light-to-heat converting particles and heat-retaining particles dispersed in the thermoplastic resin, and the light-to-heat converting particles are , 0.01 to less than 0.50% by mass, and the heat-retaining particles may be 0.01 to 70% by mass or less.

Since the fiber of the present invention can effectively convert sunlight into heat, it can provide extremely excellent cold protection and can provide a color tone with a high degree of whiteness.

The present invention will be described in more detail with the following examples, but the invention is not limited thereto.

《Manufacturing example》
<Example 1>
Tungsten oxide particles (CWO (trademark) YMDS-874, Sumitomo Metal Mining Co., Ltd.) in which hexagonal cesium tungsten oxide Cs _0.33 WO ₃ is coated with an acrylic resin having a hydroxyl group and/or an epoxy group was weighed so that the content of cesium tungsten oxide was 0.1% by mass in the composition. The tungsten oxide particles, titanium oxide particles (TIPAQUE (trademark) PF-739, Ishihara Sangyo Co., Ltd.) weighed so as to be 1.0% by mass in the composition, and polyethylene terephthalate (BELLPET (trademark) IP121B , Bell Polyester Products Co., Ltd.) was kneaded with a mixer kneader to obtain a photothermal conversion resin composition of Example 1. This photothermal conversion resin composition was formed into a film by a heat press to obtain a photothermal conversion resin film of Example 1 (thickness: 60 μm).

<Examples 2 to 6 and Comparative Examples 1 to 12>
Resin films of Examples 2 to 6 and Comparative Examples 1 to 12 were prepared by changing the amount of tungsten oxide particles and titanium oxide particles from Example 1 as shown in Table 1, or without adding them. Obtained.

<Example 7 and Comparative Example 13>
A photothermal conversion resin film of Example 7 was obtained in the same manner as in Example 1, except that the titanium oxide particles were changed to silicon oxide particles (ADMAFINE (trademark) SC2500-SQ, Admatechs Co., Ltd.). A resin film of Comparative Example 13 was obtained in the same manner as in Example 7, except that the tungsten oxide particles were not used.

<Comparative Examples 14 to 15>
Further, a resin film of Comparative Example 14 was obtained in the same manner as in Example 1 except that the tungsten oxide particles were changed to ATO particles (NF-8003, Nikken Co., Ltd.), which is an infrared absorbing material. . A resin film of Comparative Example 15 was obtained in the same manner as in Comparative Example 14, except that titanium oxide particles were not used.

"Evaluation method"
<Lamp irradiation test>
Each resin film was irradiated with a lamp having a wavelength in the near-infrared region, temperature transition was measured, and the temperature after 10 minutes of lamp irradiation was evaluated. As a lamp, PRF-250W manufactured by Iwasaki Electric Co., Ltd. was used.

<Exothermic temperature>
From the temperature of each resin film after 10 minutes of lamp irradiation, the temperature of the film of Comparative Example 1 consisting of only polyethylene terephthalate was subtracted for comparison, and the exothermic temperature of each resin film was evaluated.

<Combination effect>
The heat generation temperature of each resin film using both light-to-heat converting particles and heat-retaining particles is compared with the heat-generating temperature of a resin film containing the same amount of light-to-heat converting particles but not heat-retaining particles. Thus, whether or not the light-to-heat conversion performance is improved by using the light-to-heat conversion particles and heat-retaining particles together was evaluated. When the light-to-heat conversion performance is substantially improved by the combined use of these particles (i.e., when the exothermic temperature is increased by 1°C or more), it is rated as "○", and such combined use has substantially no effect. In the case of

<Whiteness>
Each resin film was evaluated according to CIE 1976 Lab (L*a*b* color system) in accordance with JI Z 8722 using a spectrophotometer. A spectrophotometer CR-5 manufactured by Konica Minolta was used. When the lightness index L ^* was 80 or more, it was evaluated as “◯”, and when the lightness index L ^* was less than 80, it was evaluated as “x”.

"result"
The results are shown in Tables 1 and 2. Further, FIG. 1 shows temperature profiles during lamp irradiation in Comparative Examples 1, 3 and Example 1. As shown in FIG.

From the comparison between Comparative Examples 1 and 3 and between Comparative Example 2 and Example 1, it can be seen that the addition of photothermal conversion particles increases the temperature 10 minutes after light irradiation. From the comparison between Comparative Example 2 and Example 1, and between Comparative Example 3 and Example 1, it can be seen that the combined use of photothermal conversion particles and heat-retaining particles significantly increases the temperature after 10 minutes of light irradiation. I know it will improve. Such a tendency can also be understood from the comparison between Comparative Example 4 and Example 2, the comparison between Comparative Example 5 and Example 3, and the comparison between Comparative Example 6 and Example 4.

On the other hand, from a comparison between Comparative Examples 7 and 8, and between Comparative Examples 9 and 10, when the amount of the photothermal conversion particles exceeds 0.5% by mass, heat-retaining particles are used in combination. However, it can be seen that the temperature after 10 minutes of light irradiation is substantially the same as when the photothermal conversion particles are used alone.

On the other hand, from the comparison between Comparative Example 3 and Example 5, and between Comparative Example 3 and Example 6, the heat-retaining particles, regardless of whether the amount is large or small, It can be seen that the combined effect of can be exhibited.

From the comparison between Comparative Example 3 and Example 7, it can be seen that the effect of the present invention can be exhibited not only with titanium oxide particles but also with silicon oxide particles as heat insulating particles. On the other hand, from a comparison of Comparative Examples 14 and 15, it can be seen that the effects of the present invention cannot be obtained when the photothermal conversion particles are ATO particles.

Claims (8)

comprising a thermoplastic resin, and tungsten oxide-based photothermal conversion particles and heat-retaining particles dispersed in the thermoplastic resin;
The heat-retaining particles are inorganic oxide particles (excluding those corresponding to the photothermal conversion particles),
The content of the photothermal conversion particles is 0.01% by mass or more and less than 0.50% by mass, and
The content of the heat insulating particles is 0.01 to 70% by mass,
A photothermal conversion resin composition for fibers. 2. The photothermal convertible resin composition according to claim 1, wherein said photothermal convertible particles are selected from:
General formula (1): M _x W _y O _z {wherein M is H, He, an alkali metal element, an alkaline earth metal element, a rare earth element, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, one or more elements selected from the group consisting of Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I, where W is tungsten and O is oxygen; , x, y and z are positive numbers, 0<x/y≦1, and 2.2≦z/y≦3.0}. Or general formula (2): W _y O _z {wherein W is tungsten, O is oxygen, y and z are each positive numbers, and 2.45≦z/y≦2.999 is}, tungsten oxide particles having a Magneli phase. 3. The photothermal conversion resin composition according to claim 1, wherein the photothermal conversion particles have a volume average dispersed particle size of 1 nm or more and 800 nm or less. The photothermal conversion resin composition according to any one of claims 1 to 3, wherein the heat insulating particles are particles selected from titanium oxide particles, silicon oxide particles, aluminum oxide particles, and zirconium oxide particles. 5. The photothermal conversion resin composition according to claim 1, wherein the heat-retaining particles have an average primary particle size of 10 nm or more and 5 μm or less. The thermoplastic resin is a polyolefin resin, polystyrene resin, polyester resin, acrylic resin, polyamide resin, polyvinyl alcohol resin, polyurethane resin, polycarbonate resin, polysulfone resin, derivatives thereof, and mixtures thereof. The photothermal conversion resin composition according to any one of claims 1 to 5, which is selected from the group consisting of: A photothermal conversion fiber comprising the photothermal conversion resin composition according to any one of claims 1 to 6. A method for producing a light-to-heat convertible fiber, comprising melt-spinning the light-to-heat convertible resin composition according to any one of claims 1 to 6.

Images