TWI775942B - Agricultural and horticultural soil covering film and production method thereof - Google Patents

Abstract

The agricultural and horticultural soil mulching film provided by the present invention reflects the visible light from sunlight and the like more efficiently than conventional ones, supplies the light required for plant growth to the plant side, absorbs infrared light, warms the soil, does not It causes the ambient temperature in the greenhouse, etc. to rise.

The agricultural and horticultural soil mulching film of the present invention is characterized by having a white light reflection layer containing a white light reflection material, and an infrared light absorption layer containing infrared absorbing material fine particles, and the infrared absorbing material fine particles are composite tungsten oxide fine particles. , which contains hexagonal crystals, in which the lattice constants of the a-axis and the c-axis are set to 7.3850 Å or more and 7.4186 Å or less for the a-axis, and 7.5600 Å or more to 7.6240 Å or less for the c-axis; The particle size is 100 nm or less.

Description

Soil mulching film for agriculture and horticulture and method for producing the same

The present invention relates to an infrared light absorbing layer comprising a white light reflecting layer containing a white light reflecting material, and an infrared light absorbing layer formed by coating fine particles of an infrared absorbing material that absorbs infrared rays from sunlight, etc., by reflecting visible light and absorbing infrared light, A soil mulching film for agriculture and horticulture that reflects visible light required for plant growth on the plant side, absorbs infrared light that becomes heat to warm the soil, and does not raise the ambient temperature in a greenhouse, and a method for producing the same.

Known methods for promoting plant growth include: a reflective sheet using a metal film such as aluminum, a sheet using a white light-reflecting material film to reflect white light, a sheet in which a reflective material is further coated on the reflective sheet, and the like, Methods of covering soil surfaces. However, these sheets reflect all the sunlight reaching the surface, so that while promoting plant growth, infrared light that becomes heat is also reflected. As a result, there is a problem that the temperature of the environment in the greenhouse or the like increases. In addition, generally, the reflection sheet using a metal film such as aluminum is subjected to metal vapor deposition processing such as aluminum, which has problems such as an increase in cost.

On the other hand, synthetic resin sheets such as polyethylene and polyvinyl chloride are generally known as sheets for soil insulation. However, these synthetic resin sheets generally have high infrared transmittance, so the soil heat preservation effect is insufficient. In order to solve this problem, the thermal insulation sheet proposed in Patent Document 1 is made of a knitted fabric in the form of warp yarns or weft yarns, respectively, of a band-shaped film having infrared reflectivity and a band-shaped film having infrared absorption properties. Cover the ground.

Furthermore, the film for crop cultivation proposed in Patent Document 2 is made by dispersing black or blue pigments such as carbon black in a binder, and then printing on a film with a total light transmittance of 3.0% or more and a diffuse reflectance of 40% or more. on the surface of the whitened film.

The agricultural and horticultural soil mulching film disclosed by the applicant of the present application in Patent Document 3 has a high visible light reflectance, but the material for absorbing infrared light is selected from tungsten oxide fine particles and composite tungsten oxide fine particles, and these fine particles are contained as near-infrared light. Infrared absorbing ingredients.

[Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 9-107815

[Patent Document 2] Japanese Patent Laid-Open No. 55-127946

[Patent Document 3] International Publication No. 2006/100799

However, according to the review by the present inventors, the heat insulating sheet of Patent Document 1 has a problem of high manufacturing cost because the strip-shaped thin film having infrared reflectivity is subjected to aluminum vapor deposition.

Furthermore, the crop cultivation film of Patent Document 2 has a coloring film layer area of 1.0 to 60%, and does not efficiently absorb infrared rays that can become heat, so there is a problem that the effect of warming the soil is insufficient.

Here, by using the agricultural and horticultural soil mulching film of Patent Document 3, the visible light necessary for plant growth is supplied to the plant side, and the infrared light is absorbed to warm the soil. The ambient temperature in the greenhouse etc. does not rise. However, according to further examination by the present inventors, it was found that the agricultural and horticultural soil mulch film containing tungsten oxide fine particles or composite tungsten oxide fine particles produced by the method proposed in Patent Document 3 has insufficient near-infrared absorption properties.

The present invention was made in order to solve these problems, and an object of the present invention is to provide an agricultural and horticultural soil covering film which absorbs infrared light from sunlight more efficiently than conventional ones and warms the soil, and on the other hand, provides the above-mentioned agricultural and horticultural soil covering film. When the soil mulching film for art is used in a greenhouse, etc., the ambient temperature in the greenhouse or the like does not rise.

The inventors of the present invention have made intensive studies in order to achieve the above-mentioned object. Then, considering the composition of the composite tungsten oxide fine particles belonging to the near-infrared absorbing material fine particles among the composite tungsten oxide fine particles, the crystals contained in the composite tungsten oxide fine particles are hexagonal, and the values of the a-axis and the c-axis in the lattice constants are set. , the a-axis is 7.3850Å or more and 7.4186Å or less, and the c-axis is 7.5600Å or more and 7.6240Å or less to improve crystallinity, and the average particle size of the fine particles is set to 100nm or less, and the present invention is completed.

Furthermore, it was found that the infrared absorbing film containing the composite tungsten oxide microparticles of the present invention as a near-infrared absorbing component can be more efficient than the infrared absorbing film disclosed in Patent Document 3, even if the optical interference effect is not used. The invention is completed by absorbing sunlight, especially near-infrared region light, and simultaneously allowing visible light region light to penetrate.

That is, the agricultural and horticultural soil mulching film of the first invention for solving the above-mentioned problems is an agricultural and horticultural soil mulching film having an infrared light absorbing layer containing infrared absorbing material fine particles, wherein the infrared absorbing material fine particles are Composite tungsten oxide fine particles with a hexagonal crystal structure; the lattice constants of the above composite tungsten oxide fine particles are 7.3850 Å or more and 7.4186 Å or less on the a-axis, and 7.5600 Å or more and 7.6240 Å or less on the c-axis; the above composite tungsten oxide fine particles The average particle size is 100 nm or less.

The second invention is the agricultural and horticultural soil mulch film according to the first invention, wherein the lattice constants of the composite tungsten oxide fine particles are 7.4031 Å or more and 7.4111 Å or less on the a-axis and 7.5891 Å or more and 7.6240 on the c-axis. Å or less.

A third invention is the agricultural and horticultural soil mulch film according to the first or second invention, wherein the average particle diameter of the composite tungsten oxide fine particles is 10 nm or more and 100 nm or less.

A fourth invention is the agricultural and horticultural soil mulching film according to any one of the first to third inventions, wherein in the resin binder in which the infrared light absorbing layer is provided on at least one side of the agricultural and horticultural soil mulching film, The above-mentioned composite tungsten oxide fine particles are dispersed.

A fifth invention is the agricultural and horticultural soil mulching film according to any one of the first to fourth inventions, wherein the composite tungsten oxide fine particles are dispersed in the inside of the agricultural and horticultural soil mulching film.

A sixth invention is the agricultural and horticultural soil mulch film according to any one of the first to fifth inventions, wherein the composite tungsten oxide fine particles have a crystal grain diameter of 10 nm or more and 100 nm or less.

A seventh invention is the agricultural and horticultural soil mulching film according to any one of the first to sixth inventions, wherein the composite tungsten oxide fine particles are of the general formula M _x W _y O _z (wherein M element is derived from H , He, alkali metals, alkaline earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, One or more elements selected from I and Yb; W series tungsten; O series oxygen; composite tungsten oxide fine particles represented by 0.001≦x/y≦1, 2.0≦z/y≦3.0).

The eighth invention is the agricultural and horticultural soil mulching film according to the seventh invention, wherein the M element is one or more elements selected from Cs and Rb.

A ninth invention is the agricultural and horticultural soil mulching film according to any one of the first to eighth inventions, wherein at least a part of the surface of the composite tungsten oxide fine particles is made of a film containing Si, Ti, Zr, and Al. The surface coating film of the selected at least one element is covered.

A tenth invention is the agricultural and horticultural soil covering film according to the ninth invention, wherein the surface covering film system contains oxygen atoms.

The eleventh invention is the agricultural and horticultural soil mulching film according to any one of the first to tenth inventions, wherein the film is made of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, tetrafluoroethylene-ethylene copolymer, polychlorotrifluoroethylene, trifluorotetrachloroethylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polystyrene, ethylene At least one selected from vinyl acetate and polyester resin.

A twelfth invention is the agricultural and horticultural soil mulching film according to any one of the first to eleventh inventions, wherein a white light reflecting material in which a white light reflecting material is dispersed is provided inside the film of the agricultural and horticultural soil mulching film Floor.

A thirteenth invention is the agricultural and horticultural soil mulching film according to any one of the first to twelfth inventions, which has a white light in which a white light reflecting material is coated on one surface of the agricultural and horticultural soil mulching film. A reflective layer, and an infrared light absorbing layer coated with fine particles of an infrared absorbing material on the white light reflective layer; and an infrared light absorbing layer in which fine particles of infrared absorbing material are coated on the other surface of the above-mentioned agricultural and horticultural soil mulching film.

A fourteenth invention is the agricultural and horticultural soil mulching film according to the twelfth or thirteenth invention, wherein the white light reflecting material is made of TiO ₂ , ZrO ₂ , SiO ₂ , Al ₂ O ₃ , MgO, ZnO, and CaCO ₃ . , at least one selected from BaSO ₄ , ZnS, and PbCO ₃ .

The fifteenth invention is a method for producing an agricultural and horticultural soil mulching film, which is a method for producing an agricultural and horticultural soil mulching film provided with an infrared light absorbing layer containing infrared absorbing material fine particles, wherein the infrared absorbing material fine particles contain hexagonal Composite tungsten oxide fine particles of crystal structure; the composite tungsten oxide fine particles are manufactured in such a way that the a-axis of the lattice constant is 7.3850Å or more and 7.4186Å or less, and the c-axis is 7.5600Å or more and 7.6240Å or less; While maintaining the above-mentioned lattice constant range of the above-mentioned composite tungsten oxide fine particles, a pulverizing and dispersing treatment step of making the average particle diameter 100 nm or less is performed.

A sixteenth invention is the method for producing an agricultural and horticultural soil mulching film according to the fifteenth invention, wherein the composite tungsten oxide fine particles are of the general formula M _x W _y O _z (wherein M element is selected from the group consisting of H, He, alkali, etc.). Metals, alkaline earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Among Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, I, Yb One or more selected elements; W series tungsten; O series oxygen; 0.001≦x/y≦1, 2.0≦z/y≦3.0) composite tungsten oxide fine particles.

A seventeenth invention is the method for producing an agricultural and horticultural soil mulching film according to the sixteenth invention, wherein the M element is one or more elements selected from Cs and Rb.

The eighteenth invention is the method for producing an agricultural and horticultural soil mulching film according to any one of the fifteenth to seventeenth inventions, wherein at least a part of the surface of the composite tungsten oxide fine particle is made of a material containing Si, Ti, Zr , and Al is covered with a surface coating film of at least one element selected from Al.

A nineteenth invention is the method for producing an agricultural and horticultural soil covering film according to the eighteenth invention, wherein the surface covering film contains oxygen atoms.

A twentieth invention is the method for producing an agricultural and horticultural soil mulching film according to any one of the fifteenth to nineteenth inventions, wherein the film of the agricultural and horticultural soil mulching film contains polyethylene, polypropylene, polyethylene Ethylene terephthalate, polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, tetrafluoroethylene-ethylene copolymer, polychlorotrifluoroethylene, trifluorotetrachloroethylene, polyvinyl chloride, polyvinylidene A film of one or more resins selected from vinyl chloride, polyvinyl alcohol, polystyrene, ethylene vinyl acetate, and polyester resins.

The agricultural and horticultural soil mulching film of the present invention efficiently absorbs infrared rays from sunlight, and thus, by covering the ground of cultivated plants with the agricultural and horticultural soil mulching film, the temperature of the covered ground is raised and the soil is warmed. On the other hand, when the above-mentioned agricultural and horticultural soil mulching film is used in a greenhouse or the like, there is an effect of not raising the ambient temperature in the greenhouse or the like.

1‧‧‧Thermal Plasma

2‧‧‧High frequency coil

3‧‧‧Sheath gas supply nozzle

4‧‧‧Plasma Gas Supply Nozzle

5‧‧‧Material powder supply nozzle

6‧‧‧Reaction Vessel

7‧‧‧Suction tube

8‧‧‧Filter

FIG. 1 is a conceptual diagram of a high-frequency plasma reaction apparatus used in the present invention.

The agricultural and horticultural soil mulching film of the present invention is an agricultural and horticultural soil mulching film comprising composite tungsten oxide fine particles having a predetermined structure as the infrared absorbing material fine particles. Here, with regard to the form of the agricultural and horticultural soil mulching film for carrying out the present invention, [a] composite tungsten oxide fine particles, [b] synthesis method of composite tungsten oxide fine particles, and [c] composite tungsten oxide fine particle dispersion liquid , [d] The sequence of agricultural and horticultural soil mulching films will be described.

[a] Composite tungsten oxide fine particles

The agricultural and horticultural soil mulching film of the present invention contains composite tungsten oxide fine particles belonging to the infrared absorbing material fine particles, and is a film having a characteristic of high absorptivity for light in the infrared region. Here, first, the composite tungsten oxide fine particles which are the infrared absorbing material fine particles will be described.

The composite tungsten oxide fine particle system of the present invention is a composite tungsten oxide fine particle system having near-infrared absorption properties and containing a hexagonal crystal structure, and the lattice constant of the hexagonal composite tungsten oxide fine particle system has an a-axis of 7.3850 Å or more and 7.4186 Å Below, the c-axis is 7.5600 Å or more and 7.6240 Å or less. On the other hand, the ratio of (c-axis lattice constant/a-axis lattice constant) is preferably 1.0221 or more and 1.0289 or less. In addition, the average particle diameter of the composite tungsten oxide fine particles of the present invention is 100 nm or less.

Hereinafter, the composite tungsten oxide fine particles of the present invention are based on: (1) crystal structure and lattice constant, (2) grain size and crystal grain diameter, (3) composition of composite tungsten oxide fine particles, (4) composite tungsten The surface coating of oxide fine particles and the order of conclusion (5) will be described.

(1) Crystal structure and lattice constant

The composite tungsten oxide microparticles of the present invention can be formed into tetragonal or cubic tungsten bronze structures in addition to hexagonal crystals, and can be an effective near-infrared absorbing material in either structure. However, depending on the crystal structure formed by the composite tungsten oxide fine particles, the absorption position in the near-infrared region tends to change. The hexagonal crystal tends to move to the longer wavelength side than the tetragonal crystal. In addition, with the change of the absorption position, the light absorption in the visible light region is the least in hexagonal crystals, followed by tetragonal crystals, and among them, cubic crystals are the largest.

Based on the above findings, it is preferable to use hexagonal tungsten bronze for the purpose of making the visible light region more transparent and absorbing the near-infrared region light. When the composite tungsten oxide microparticles have a hexagonal crystal structure, the transmittance of the microparticles in the visible light region is improved, and the absorption in the near-infrared region is improved. In this hexagonal crystal structure, an octahedron formed of WO ₆ units is assembled in 6 to form a hexagonal void (tunnel), M element is arranged in the void to constitute one unit, and this one unit is further composed A large number of aggregates form a hexagonal crystal structure.

In order to obtain the effect of improving the penetration of the visible light region and the absorption of the near-infrared region of the present invention, as long as the composite tungsten oxide particles contain a unit structure (the octahedron formed by the WO ₆ unit is composed of 6 aggregates) A hexagonal void, a structure in which the element M is arranged in the void) may be used.

When the cation of the M element is added to the hexagonal void, the absorption in the near-infrared region is improved. Here, the hexagonal crystal is generally formed when the M element having a large ionic radius is added. Specifically, when one or more kinds selected from Cs, Rb, K, Tl, In, and Ba are added, the hexagonal crystal can be easily formed. Hexagonal crystals are preferred.

Furthermore, by adding one or more kinds of composite tungsten oxide fine particles selected from Cs and Rb to the M element with a large plasma radius, it is possible to achieve both absorption in the near-infrared region and penetration in the visible light region.

Furthermore, when two or more kinds of M elements are selected, one of which is selected from Cs, Rb, K, Tl, Ba, and In, and the rest is selected from one or more elements constituting the M element, it can also be hexagonal. crystal.

When the Cs tungsten oxide particles of Cs are selected as the M element, the lattice constant of the a-axis is preferably 7.4031Å or more and 7.4186Å or less, the c-axis is 7.5750Å or more and 7.6240Å or less, and the a-axis is preferably 7.4031 Å. Å or more and 7.4111 Å or less, and the c-axis is 7.5891 Å or more and 7.6240 Å or less.

When the M element is selected as the Rb tungsten oxide fine particle of Rb, its lattice constant is preferably 7.3850 Å or more and 7.3950 Å or less for the a-axis, and 7.5600 Å or more and 7.5700 Å or less for the c-axis.

When the M element is CsRb tungsten oxide fine particles of Cs and Rb, its lattice constant is preferably 7.3850Å or more and 7.4186Å or less for the a-axis, and 7.5600Å or more and 7.6240Å or less for the c-axis.

However, the M element is not limited to the above-mentioned Cs or Rb. Even if the M element is an element other than Cs or Rb, as long as it can exist in the form of adding the M element in the hexagonal space formed by the WO ₆ unit.

When the composite tungsten oxide fine particles having a hexagonal crystal structure of the present invention are represented by the general formula M _x W _y O _z , and when the composite tungsten oxide fine particles have a uniform crystal structure, the addition amount of the M element is 0.001≦x /y≦1, preferably 0.2≦x/y≦0.5, more preferably 0.20≦x/y≦0.37, particularly preferably x/y=0.33. The reason for this is that theoretically, when z/y=3, it can be considered that by setting x/y=0.33, the added M element is arranged in all the hexagonal voids. Typical examples include Cs _0.33 WO ₃ , Cs _0.03 Rb _0.30 WO ₃ , Rb _0.33 WO ₃ , K _0.33 WO ₃ , Ba _0.33 WO ₃ and the like.

Here, the inventors of the present invention have conducted in-depth research on a strategy for further enhancing the near-infrared absorption function of the composite tungsten oxide fine particles, and have considered a configuration that further increases the amount of free electrons contained therein.

That is, the strategy for increasing the amount of free electrons is to give appropriate strain or deformation to the contained hexagonal crystals in addition to mechanically treating the composite tungsten oxide fine particles. It is considered that in this hexagonal crystal to which appropriate strain or deformation is imparted, the overlapping state of electron orbitals of atoms constituting the crystal grain structure changes, and the amount of free electrons increases.

Based on the above-mentioned concept, the inventors of the present invention, for the particles of composite tungsten oxide produced in the calcination step of "[b] Method for synthesizing composite tungsten oxide fine particles" described later, in the dispersing step when producing a dispersion liquid of composite tungsten oxide fine particles By pulverizing the composite tungsten oxide particles under predetermined conditions, the crystal structure is strained or deformed, the amount of free electrons is increased, and the near-infrared absorption function of the composite tungsten oxide particles is improved.

Then, from this study, the particles of the composite tungsten oxide produced through the calcination step were examined focusing on each particle. Accordingly, it was found that the lattice constants and the constituent element compositions of the respective particles varied.

As a result of further investigations, it was found that the desired optical properties can still be exhibited if the lattice constant of the finally obtained composite tungsten oxide fine particles is within a predetermined range, even if the lattice constant or constituent element composition varies among the individual particles.

The present inventors who obtained the above-mentioned findings further measured the a-axis and c-axis belonging to the lattice constant in the crystal structure of the composite tungsten oxide fine particles, and grasped the degree of strain or deformation of the crystal structure of the fine particles. The optical properties exhibited by the fine particles were investigated. Then, as a result of this study, it was found that the hexagonal composite tungsten oxide microparticles exhibit wavelengths in the range of 350nm to 600nm when the a-axis is 7.3850Å or more and 7.4186Å or less, and the c-axis is 7.5600Å or more and 7.6240Å or less. It has a maximum value and a minimum value of light transmittance in the wavelength range of 800 nm to 2100 nm, and belongs to the near-infrared absorbing material fine particles that exhibit an excellent near-infrared absorption effect.

Furthermore, it was found that the hexagonal composite tungsten oxide microparticles having the near-infrared absorbing material microparticles of the present invention whose a-axis is 7.3850 Å or more and 7.4186 Å or less and c-axis are 7.5600 Å or more and 7.6240 Å or less are expressed as the amount of M element added. When the x/y value is in the range of 0.001≦x/y≦1, preferably in the range of 0.20≦x/y≦0.37, a particularly excellent near-infrared absorption effect is exhibited.

Furthermore, it has also been found that the composite tungsten oxide microparticles as the near-infrared absorbing material microparticles are preferably single crystals having an amorphous phase volume ratio of 50% or less.

The composite tungsten oxide fine particles are single crystals with an amorphous phase volume ratio of 50% or less, and it is considered that the crystal grain diameter can be 10 nm or more and 100 nm or less while maintaining the lattice constant within the above-mentioned predetermined range, and it is considered that excellent performance can be exhibited. optical properties.

Furthermore, the case where the composite tungsten oxide microparticles are single crystals can be performed by observing only the same lattice pattern without observing the grain boundaries inside each microparticle in an electron microscope image such as a transmission electron microscope. confirm. In addition, when the volume ratio of the amorphous phase of the composite tungsten oxide fine particles is 50% or less, the same lattice pattern can be observed in the entire fine particle in the transmission electron microscope image in the same way, and the lattice pattern is almost It was confirmed that no ambiguity was observed.

In addition, since the amorphous phase exists in the outer peripheral portion of each fine particle in many cases, the volume ratio of the amorphous phase can be calculated in many cases by paying particular attention to the outer peripheral portion of each fine particle. For example, when the spherical composite tungsten oxide fine particles are layered with an amorphous phase with unclear lattice patterns on the outer periphery of the fine particles, and the thickness is less than 10% of the average particle size, the composite tungsten oxide fine particles The volume ratio of the amorphous phase is 50% or less.

On the other hand, when the composite tungsten oxide fine particles are dispersed in a solid medium matrix such as a resin constituting the composite tungsten oxide fine particle dispersion, if the average particle diameter of the dispersed composite tungsten oxide fine particles is deducted from the crystal grain diameter If the value is 20% or less of the average particle size, the composite tungsten oxide fine particles can be said to be single crystals with an amorphous phase volume ratio of 50% or less.

From the above, it is preferable to follow the average particle size of the composite tungsten oxide fine particles dispersed in the composite tungsten oxide fine particle dispersion, and deduct the value of the grain diameter to be 20% or less of the average particle size value. , and appropriately adjust the synthesis step, pulverization step, and dispersion step of the composite tungsten oxide microparticles according to the manufacturing equipment.

In addition, the crystal structure or lattice constant of the composite tungsten oxide fine particles is measured by X-ray diffraction method for the composite tungsten oxide fine particles obtained by removing the solvent of the dispersion liquid for forming a near-infrared absorber. The crystal structure contained in the crystal can be calculated by the Rietveld method to calculate the a-axis length and c-axis length of the lattice constant.

(2) Particle size and grain diameter

The average particle diameter of the composite tungsten oxide fine particles of the present invention is 100 nm or less. From the viewpoint of exhibiting more excellent infrared absorption properties, the average particle diameter is preferably 10 nm or more and 100 nm or less, more preferably 10 nm or more and 80 nm or less, and particularly preferably 10 nm or more and 60 nm or less. The most excellent infrared absorption characteristics can be exhibited when the average particle diameter is in the range of 10 nm or more and 60 nm or less.

Here, the "average particle size" refers to the diameter value of each unagglomerated composite tungsten oxide fine particle, and refers to the particle diameter of the composite tungsten oxide fine particle contained in the composite tungsten oxide fine particle dispersion described later.

On the other hand, the average particle diameter does not include the aggregate diameter of the composite tungsten oxide fine particles, and is different from the dispersed particle diameter.

In addition, the average particle diameter is calculated from the electron microscope image of the near-infrared absorbing material fine particle.

The average particle size of the composite tungsten oxide fine particles contained in the composite tungsten oxide fine particle dispersion is obtained from the transmission electron microscope image of the flake sample of the composite tungsten oxide fine particle dispersion obtained by cross-section processing, using image processing. The device measures the particle size of 100 composite tungsten oxide fine particles, and then uses an image processing device to measure and calculate the average value. For the cross-section processing to take out the thinned sample, a microtome, a cross-section polisher, a beam ion beam (FIB) apparatus, or the like can be used. In addition, the average particle diameter of the composite tungsten oxide fine particles contained in the composite tungsten oxide fine particle dispersion is the average particle diameter of the composite tungsten oxide fine particles dispersed in the solid medium belonging to the matrix.

Furthermore, from the viewpoint of exhibiting excellent infrared absorption properties, the crystal grain diameter of the composite tungsten oxide fine particles is preferably 10 nm or more and 100 nm or less, more preferably 10 nm or more and 80 nm or less, and particularly preferably 10 nm or more and 60 nm or less. The reason is that when the crystal grain diameter is within the range of 10 nm or more and 60 nm or less, the most excellent infrared absorption characteristics can be exhibited.

Furthermore, the lattice constant or grain size of the composite tungsten oxide fine particles contained in the composite tungsten oxide fine particle dispersion liquid obtained after the crushing treatment, pulverization treatment or dispersion treatment described later is determined from the composite tungsten oxide fine particles. The composite tungsten oxide fine particles obtained by removing the volatile components from the dispersion liquid or the composite tungsten oxide fine particles contained in the composite tungsten oxide fine particle dispersion obtained from the composite tungsten oxide fine particle dispersion liquid can be maintained.

As a result, both the composite tungsten oxide fine particle dispersion of the present invention and the composite tungsten oxide fine particle dispersion containing the composite tungsten oxide fine particles can exhibit the effects of the present invention.

(3) Composition of composite tungsten oxide particles

The composite tungsten oxide microparticles of the present invention are preferably of the general formula M _x W _y O _z (wherein M is selected from H, He, alkali metals, alkaline earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, Select one or more elements from S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, I, Yb; W series tungsten, O series oxygen, 0.001≦x /y≦1, 2.0≦z/y≦3.0) composite tungsten oxide fine particles.

The composite tungsten oxide fine particles represented by the general formula M _x W _y O _z will be described.

The M element, x, y, z and its crystal structure in the general formula M _x W _y O _z are closely related to the free electron density of the composite tungsten oxide fine particles, and greatly affect the near-infrared absorption characteristics.

Generally speaking, effective free electrons do not exist in tungsten trioxide (WO ₃ ), so the near-infrared absorption characteristics are low.

Here, the present inventors found that by adding M element (wherein M element is selected from H, He, alkali metals, alkaline earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, Select one or more elements from S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, I, Yb) to form a composite tungsten oxide, and then in the composite Free electrons are generated in tungsten oxide, and the absorption characteristics derived from free electrons are exhibited in the near-infrared region, and it is effective as a near-infrared absorbing material near a wavelength of 1000 nm, and the composite tungsten oxide is chemically stable. A near-infrared absorbing material with excellent weather resistance. In addition, the M elements are preferably Cs, Rb, K, Tl, Ba, and In, and when the M elements are Cs and Rb in particular, the composite tungsten oxide tends to have a hexagonal crystal structure. As a result, it was also found that visible light penetrates and absorbs near infrared rays, which is particularly preferable for the reasons described later. In addition, when two or more kinds of M elements are selected, one of which is selected from Cs, Rb, K, Tl, Ba, and In, and the rest is selected from one or more elements constituting the M element, it will also form a hexagonal crystal.

Here, a description will be given of the value of x which is found by the present inventors to indicate the amount of addition of the M element.

When the x/y value is 0.001 or more, a sufficient amount of free electrons can be generated, and the target near-infrared absorption characteristics can be obtained. On the other hand, the more the M element is added, the more free electrons are supplied, and the more the near-infrared absorption characteristics are improved. However, when the x/y value is about 1, the effect is saturated. In addition, if the value of x/y is 1 or less, the formation of impurity phases in the composite tungsten fine particles can be avoided, which is preferable.

Next, the z value found by the present inventors to indicate oxygen amount control will be described.

In the composite tungsten oxide fine particles represented by the general formula M _x W _y O _z , the z/y value is preferably 2.0≦z/y≦3.0, more preferably 2.2≦z/y≦3.0, and particularly preferably 2.6≦z/ y≦3.0, the best system is 2.7≦z/y≦3.0. The reason is that if the z/y value is 2.0 or more, undesired WO ₂ crystal phases can be avoided in the composite tungsten oxide, and the chemical stability of the material can be obtained, so it can be used as an effective infrared absorbing material. On the other hand, if the z/y value is 3.0 or less, a necessary amount of free electrons is generated in the tungsten oxide, and it becomes an efficient infrared absorbing material.

(4) Surface coating of composite tungsten oxide fine particles

In order to improve the weather resistance of the composite tungsten oxide fine particles, it is preferable to coat at least a part of the surface of the composite tungsten oxide fine particles with a surface coating film containing one or more elements selected from silicon, zirconium, titanium, and aluminum. These surface coating films are basically transparent, and the visible light transmittance of the composite tungsten oxide fine particles will not decrease due to the addition. The coating method is not particularly limited, and the surface of the composite tungsten oxide fine particles can be coated by adding a metal alkoxide containing the above-mentioned elements to a solution in which the composite tungsten oxide fine particles are dispersed. In this case, the surface coating film contains oxygen atoms, and more preferably, the surface coating film is composed of an oxide.

(5 Conclusion

The lattice constant, the average particle diameter, and the crystal grain diameter of the composite tungsten oxide fine particles described above can be controlled by using predetermined production conditions. Specifically, the temperature at which the fine particles are generated (calcination temperature), the generation time (calcination time), the generation environment (calcination environment), and the form of the precursor material are used in the thermoplasma method, the solid-phase reaction method, etc. to be described later. It can be controlled by appropriate setting of manufacturing conditions such as annealing treatment after generation and doping of impurity elements.

[b] Synthesis method of composite tungsten oxide fine particles

The method for synthesizing the composite tungsten oxide fine particles of the present invention will be described.

The method for synthesizing the composite tungsten oxide fine particles of the present invention includes, for example, a thermoplasma method in which a tungsten compound starting material is thrown into a thermoplasma, or a solid-phase reaction in which a tungsten compound starting material is heat-treated in a reducing gas atmosphere. Law. The composite tungsten oxide fine particles synthesized by the thermoplasma method or the solid-phase reaction method are then subjected to dispersion treatment or pulverization and dispersion treatment.

The following describes the composite tungsten oxide fine particles synthesized in the order of (1) thermoplasmic method, (2) solid-phase reaction method, and (3) synthesized.

(1) Thermoplasma method

About the thermoplasma method, (i) the raw material used for the thermoplasma method, (ii) the thermoplasma method and its conditions are demonstrated in this order.

(i) Raw materials used in the thermoplasma method

When synthesizing the composite tungsten oxide fine particles of the present invention by the thermoplasma method, a mixed powder of a tungsten compound and an M element compound can be used as a raw material.

The tungsten compound is preferably obtained from tungstic acid (H ₂ WO ₄ ); ammonium tungstate; tungsten hexachloride; Choose one or more of them.

Furthermore, as the M element compound, it is preferable to use one or more kinds selected from oxides, hydroxides, nitrates, sulfates, chlorides, and carbonates of the M element.

The aqueous solution containing the above-mentioned tungsten compound and the above-mentioned M element compound, according to the ratio of M element to W element, becomes M _x W _y O _z (wherein M is the above-mentioned M element, W is tungsten, O is oxygen, 0.001≦x /y≦1.0, 2.0≦z/y≦3.0), wet mixing is performed in the form of the ratio of M element and W element. Then, by drying the obtained mixed solution, a mixed powder of the M element compound and the tungsten compound is obtained, and the mixed powder can be used as a raw material for the thermoplasma method.

Furthermore, the composite tungsten oxide obtained by the first-stage calcination of the mixed powder in an environment of an inert gas alone or a mixed gas environment of an inert gas and a reducing gas can also be used as a raw material for the thermoplasma method. . In addition, the first stage is calcined in an atmosphere of a mixed gas of an inert gas and a reducing gas, and the calcined product of the first stage is calcined in an inert gas atmosphere in the second stage, and the two-stage calcination is obtained. The composite tungsten oxide can also be used as a raw material for the thermoplasma method.

(ii) Thermoplasmic method and its conditions

The thermal plasma used in the present invention can be suitably used, for example, any one of DC arc plasma, high-frequency plasma, microwave plasma, and low-frequency AC plasma; or a combination of these plasmas; The plasma generated by the electrical method of applying a magnetic field to the DC plasma; the plasma generated by irradiating a high-output laser; the plasma generated by the high-output electron beam or ion beam. In particular, no matter what kind of thermoplasma is used, it is a thermoplasma with a high temperature portion of 10,000 to 15,000K, and a plasma that can control the generation time of fine particles is particularly preferred.

The raw material supplied in the thermoplasma with the high temperature part will evaporate instantaneously in the high temperature part. On the other hand, the evaporated raw material is condensed in the process of reaching the plasma tail flame, and is rapidly cooled and solidified outside the plasma flame to generate composite tungsten oxide fine particles.

An example in the case of using a high-frequency plasma reaction apparatus will be described with reference to FIG. 1 and a synthesis method.

First, the inside of the reaction system composed of the inside of the water-cooled quartz double-layer tube and the inside of the reaction vessel 6 was evacuated to about 0.1 Pa (about 0.001 Torr) using a vacuum exhaust device. After the inside of the reaction system was evacuated, the inside of the reaction system was filled with argon gas to form an argon gas circulation system of 1 atmosphere.

Then, argon, a mixed gas of argon and helium (Ar-He mixed gas), or a mixture of argon and nitrogen was introduced into the reaction vessel from the plasma gas supply nozzle 4 at a flow rate of 30 to 45 L/min as the plasma gas. Any gas selected from the gas (Ar-N ₂ mixed gas). On the other hand, the sheath gas flowing in immediately outside the plasma region was introduced into the Ar-He mixed gas from the sheath gas supply nozzle 3 at a flow rate of 60 to 70 L/min.

Then, an alternating current is applied to the high-frequency coil 2, and the thermoplasma 1 is generated by a high-frequency electromagnetic field (frequency: 4 MHz). At this time, the high-frequency power is set to 30 to 40 kW.

Furthermore, using the powder supply nozzle 5, the mixed powder of the M element compound and the tungsten compound, or the composite tungsten oxide obtained by the above synthesis method, is supplied from the gas supply device with 6~98L/min of argon as The carrier gas is introduced into the thermoplasm according to the ratio of the supply speed of 25~50g/min, and the reaction is carried out for a predetermined time. After the reaction, since the generated composite tungsten oxide fine particles are accumulated on the filter 8 through the suction pipe 7, they can be recovered.

The carrier gas flow rate and feedstock supply rate can greatly affect the generation time of the microparticles. Here, the carrier gas flow rate is preferably 6 L/min or more and 9 L/min or less, and the raw material supply rate is preferably 25 to 50 g/min.

Furthermore, it is preferable to set the plasma gas flow rate to 30 L/min or more and 45 L/min or less, and the sheath gas flow rate to 60 L/min or more and 70 L/min or less. The plasma gas system has the function of maintaining a thermoplasmic region with a high temperature of 10000~15000K, and the sheath gas system has the function of cooling the inner wall of the quartz torch in the reaction vessel to prevent the quartz torch from melting. At the same time, since the plasma gas and the sheath gas will affect the shape of the plasma region, the flow rate of these gases becomes an important parameter for controlling the shape of the plasma region. The higher the plasma gas and sheath gas flow rates, the more the shape of the plasma region extends toward the gas flow direction, and the more gentle the temperature slope of the plasma tail flame, so the longer the generation time of the generated particles, the better the crystallinity can be generated. microparticles.

When the grain diameter of the composite tungsten oxide synthesized by the thermoplasma method exceeds 200 nm, or the dispersion of the composite tungsten oxide in the composite tungsten oxide microparticle dispersion liquid made of the composite tungsten oxide obtained by the synthesis by the thermoplasma method When the particle size exceeds 200 nm, pulverization and dispersion treatment described later may be performed. When the composite tungsten oxide is synthesized by the thermoplasma method, the plasma conditions, or the subsequent pulverization and dispersion treatment conditions are appropriately selected to determine the a-axis that can give the composite tungsten oxide the average particle size, grain diameter, and lattice constant. The effect of the present invention can be exhibited under the pulverization conditions (micronization conditions) of the length and the c-axis length.

(2) Solid-phase reaction method

The solid-phase reaction method will be described in the order of (i) raw materials used in the solid-phase reaction method, (ii) calcination of the solid-phase reaction method, and conditions thereof.

(i) Raw materials used in the solid-phase reaction method

When the composite tungsten oxide fine particles of the present invention are synthesized by the solid-phase reaction method, the raw materials are a tungsten compound and an M element compound.

The tungsten compound is preferably obtained from tungstic acid (H ₂ WO ₄ ); ammonium tungstate; tungsten hexachloride; Choose one or more of them.

Furthermore, the general formula M _x W _y O _z of a better embodiment (wherein M is one or more elements selected from Cs, Rb, K, Tl, and Ba; 0.001≦x/y≦1, 2.0≦z The M element compound used in the production of the composite tungsten oxide fine particle raw material represented by /y≦3.0) is preferably selected from oxides, hydroxides, nitrates, sulfates, chlorides, and carbonates of the M element. more than one species.

In addition, a compound containing one or more impurity elements selected from Si, Al, and Zr (in the present invention, it may be described as an "impurity element compound") may be contained as a raw material. The impurity element compound does not react with the composite tungsten compound in the subsequent calcination step, but inhibits the crystal growth of the composite tungsten oxide and has the effect of preventing crystal coarsening. The compound containing impurity elements is preferably one or more selected from oxides, hydroxides, nitrates, sulfates, chlorides, and carbonates, and more preferably colloidal silica or colloidal oxides with a particle size of 500 nm or less aluminum.

The above-mentioned tungsten compound and the aqueous solution containing the above-mentioned M element compound, according to the ratio of M element to W element, are M _x W _y O _z (wherein M is the above-mentioned M element, W is tungsten, O is oxygen, 0.001≦x/ Wet mixing is carried out so that the ratio of M element and W element of y≦1.0, 2.0≦z/y≦3.0) is used. When an impurity element compound is contained as a raw material, wet mixing is performed so that the impurity element compound becomes 0.5 mass % or less. Then, by drying the obtained mixed solution, a mixed powder of an M element compound and a tungsten compound, or a mixed powder of an M element compound containing an impurity element compound and a tungsten compound can be obtained.

(ii) Calcination by solid-phase reaction method and its conditions

The mixed powder of the M element compound and the tungsten compound produced by wet mixing, or the mixed powder of the M element compound containing the impurity element compound and the tungsten compound, is in a separate inert gas environment, or in an inert gas and reducing property. The calcination is carried out in one stage in a mixed gas atmosphere of gas. The calcination temperature is preferably close to the temperature at which the composite tungsten oxide fine particles start to crystallize. Specifically, the calcination temperature is preferably 1000°C or lower, more preferably 800°C or lower, and particularly preferably 800°C or lower and 500°C or higher.

The reducing gas is not particularly limited, but is preferably H ₂ . In addition, when H ₂ is used in the reducing gas system, its concentration can be appropriately selected in accordance with the calcination temperature and the amount of starting materials, and the rest is not particularly limited. For example, it is 20 volume % or less, preferably 10 volume % or less, and more preferably 7 volume % or less. The reason is that if the concentration of the reducing gas is 20% by volume or less, it is possible to avoid the generation of WO ₂ having no insolation absorption function due to rapid reduction. At this time, by controlling the firing conditions, the average particle diameter, crystal grain diameter, and a-axis length and c-axis length of the lattice constant of the composite tungsten oxide fine particles of the present invention can be set to predetermined values.

In particular, in the synthesis of the composite tungsten oxide fine particles, tungsten trioxide may be used instead of the above-mentioned tungsten compound.

(3) Synthesized composite tungsten oxide fine particles

When a composite tungsten oxide fine particle dispersion liquid, which will be described later, is prepared using composite tungsten oxide fine particles obtained by a synthesis method by a thermoplasma method or a solid-phase reaction method, when the dispersed particle size of fine particles contained in the dispersion liquid exceeds 200 nm , it is sufficient to perform pulverization and dispersion treatment in the step of producing the composite tungsten oxide fine particle dispersion liquid, which will be described later. However, on the premise that the values of the average particle size, crystal grain diameter, and a-axis length and c-axis length of the composite tungsten oxide particles obtained by pulverization and dispersion treatment can achieve the scope of the present invention, the present invention The composite tungsten oxide fine particle dispersion obtained by the composite tungsten oxide fine particle or its dispersion liquid can achieve excellent near-infrared absorption characteristics.

As described above, the composite tungsten oxide fine particle system of the present invention has an average particle diameter of 100 nm or less.

Here, when the average particle diameter of the composite tungsten oxide fine particles obtained by the method described in "[b] The method for synthesizing composite tungsten oxide fine particles" exceeds 100 nm, the composite tungsten oxide fine particles are pulverized and dispersed to be finely divided, and composite tungsten oxide fine particles are produced. The step of tungsten oxide fine particle dispersion (pulverizing and dispersing treatment steps), and subjecting the prepared composite tungsten oxide fine particle dispersion to drying treatment to remove volatile components (almost all solvents), the composite of the present invention can be produced. Tungsten oxide fine particles.

The equipment for drying treatment is preferably an air dryer, a universal mixer, a belt mixer, a vacuum flow dryer, a vibration flow dryer, from the viewpoint that heating and/or decompression can be applied, and the mixing or recovery of the fine particles is easy. Dryers, freeze dryers, conical spiral mixing dryers, rotary kilns, spray dryers, pulverizing dryers, etc., but are not limited to these.

[c] Composite tungsten oxide fine particle dispersion

The composite tungsten oxide fine particle dispersion liquid for producing the agricultural and horticultural soil mulching film of the present invention will be described.

The composite tungsten oxide microparticle dispersion liquid is composed of the composite tungsten oxide microparticles obtained by the above-mentioned synthesis method, mixed with water, an organic solvent, a liquid resin, a liquid plasticizer for plastics, a polymer monomer or a mixture of these. The liquid medium of the selected mixed slurry, as well as an appropriate amount of dispersant, coupling agent, surfactant, etc., are pulverized and dispersed by a medium stirring mill.

Furthermore, it is characterized in that the fine particles in the solvent are in a good dispersion state and the dispersed particle size is 1 to 200 nm. In addition, the content of the composite tungsten oxide fine particles contained in the composite tungsten oxide fine particle dispersion liquid is preferably 0.01 mass % or more and 80 mass % or less.

Hereinafter, for the composite tungsten oxide fine particle dispersion of the present invention, according to (1) solvent, (2) dispersant, (3) pulverization and dispersion method, (4) dispersion particle size, (5) binder, and other additives explained in order.

(1) Solvent

The liquid solvent used in the composite tungsten oxide fine particle dispersion is not particularly limited, as long as it is combined with the coating conditions and coating environment of the composite tungsten oxide fine particle dispersion, and appropriately added inorganic binders, resin binders, etc., Then make an appropriate selection. For example, liquid solvents include water, organic solvents, oils and fats, liquid resins, liquid plasticizers for dielectric resins, polymer monomers, or mixtures thereof.

Here, as the organic solvent, various substances such as alcohol-based, ketone-based, hydrocarbon-based, glycol-based, and water-based can be selected. Specifically, alcohol-based solvents such as methanol, ethanol, 1-propanol, isopropanol, butanol, amyl alcohol, benzyl alcohol, and diacetone alcohol can be used; acetone, methyl ethyl ketone, methyl acetone, methyl isobutyl ketone, cyclohexane Ketone-based solvents such as ketone and isophorone; ester-based solvents such as 3-methyl-methoxy-propionate; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol isopropyl ether, propylene glycol mono Methyl ether, propylene glycol monoethyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate and other glycol derivatives; formamide, N-methylformamide, dimethylformamide, dimethylacetamide, N -Amides such as methyl-2-pyrrolidone; aromatic hydrocarbons such as toluene and xylene; 1,2-dichloroethane, chlorobenzene, etc. Among these organic solvents, dimethyl ketone, methyl ethyl ketone, methyl isobutyl ketone, toluene, propylene glycol monomethyl ether acetate, n-butyl acetate and the like are particularly preferred.

The fats and oils are preferably vegetable fats and oils or vegetable-derived fats and oils. For vegetable oils, drying oils such as linseed oil, sunflower oil, tung oil, and perilla oil; semi-drying oils such as sesame oil, cottonseed oil, rapeseed oil, soybean oil, rice bran oil, and mustard oil; olive oil, coconut oil, palm oil, Non-drying oils like dehydrated castor oil. As the vegetable oil-derived compound system, fatty acid monoesters, ethers, and the like obtained by direct ester-reaction of the fatty acid and monoalcohol of the vegetable oil can be used. In addition, commercially available petroleum-based solvents can also be used as oils and fats, for example, ISOPER (registered trademark) E, EXXSOL (registered trademark) Hexane, Heptane, E, D30, D40, D60, D80, D95, D110, D130, etc.

As a liquid plasticizer system for dielectric resins, a well-known liquid plasticizer represented by an organic acid ester system, a phosphoric acid ester system, etc. can be used.

Here, the liquid plasticizers include, for example: plasticizers of compounds of monohydric alcohols and organic acid esters; plasticizers belonging to ester series such as polyhydric alcohol organic acid ester compounds; plasticizers belonging to phosphoric acid series such as organic phosphoric acid-based plasticizers , preferably in liquid form at room temperature. Among them, a plasticizer which is an ester compound synthesized from a polyhydric alcohol and a fatty acid is preferable.

The ester compound synthesized from a polyhydric alcohol and a fatty acid is not particularly limited, and examples thereof include glycols such as triethylene glycol, tetraethylene glycol, and tripropylene glycol, and butyric acid, isobutyric acid, caproic acid, 2 - A glycol-based ester compound obtained by reacting monobasic organic acids such as ethylbutyric acid, heptanoic acid, n-octanoic acid, 2-ethylhexanoic acid, nonanoic acid (n-nonanoic acid), and capric acid. Moreover, tetraethylene glycol, tripropylene glycol, the ester compound with the said monobasic organic acid, etc. are mentioned, for example.

Among them, triethylene glycol dicaproate, triethylene glycol di(2-ethylbutyrate), triethylene glycol dicaprylate, triethylene glycol di(2-ethylhexanoic acid) are preferable. fatty acid esters such as triethylene glycol. It is preferably a fatty acid ester of triethylene glycol.

In addition, the so-called "polymer monomer" refers to a monomer that forms a polymer by polymerization or the like, and the preferred polymer monomer system used in the present invention includes, for example, methyl methacrylate monomer and acrylate monomer. Or styrene resin monomer, etc.

The liquid solvent systems described above can be used alone or in combination of two or more. Moreover, you may add acid or alkali to these liquid solvents as needed, and may adjust pH.

(2) Dispersant

Furthermore, in order to further improve the dispersion stability of the composite tungsten oxide fine particles in the composite tungsten oxide fine particle dispersion liquid and avoid the coarsening of the dispersed particle size caused by re-agglomeration, it is preferable to add various dispersants and surfactants. , couplers, etc. The dispersing agent, coupling agent and surfactant can be selected according to the application, and preferably those having functional groups such as amine-containing groups, hydroxyl groups, carboxyl groups, or epoxy groups. These functional groups have the effect of preventing adsorption and agglomeration on the surface of the composite tungsten oxide fine particles, and even in the infrared absorbing film, the composite tungsten oxide fine particles of the present invention can be uniformly dispersed. More desirable is a polymer-based dispersant having any one of these functional groups in the molecule.

Examples of such dispersants include: SOLSPERSE (registered trademark) (hereinafter the same) 3000, 5000, 9000, 11200, 12000, 13000, 13240, 13650, 13940, 16000, 17000, 18000, 20000, manufactured by Lubrizol Corporation of Japan, 21000、24000SC、24000GR、26000、27000、28000、31845、32000、32500、32550、32600、33000、33500、34750、35100、35200、36600、37500、38500、39000、41000、41090、 53095、55000、56000、 71000, 76500, J180, J200, M387, etc; Registered trademark) (the same below) - 101, 102, 103, 106, 107, 108, 109, 110, 111, 112, 116, 130, 140, 142, 145, 154, 161, 162, 163, 164, 165 , 166, 167, 168, 170, 171, 174, 180, 181, 182, 183, 184, 185, 190, 191, 192, 2000, 2001, 2009, 2020, 2025, 2050, 2070, 2095, 2096, 2150 , 2151, 2152, 2155, 2163, 2164; Anti-Terra (registered trademark) (the same below) - U, 203, 204, etc.; BYK (registered trademark) (the same below) - P104, P104S, P105, P9050, P9051, P9060, P9065, P9080, 051, 052, 053, 054, 055, 057, 063, 065, 066N, 067A, 077, 088, 141, 220S, 300, 302, 306, 307, 310, 315, 320, 322, 323, 325, 330, 331, 333, 337, 340, 345, 346, 347, 348, 350, 354, 355, 358N, 361N, 370, 375, 377, 378, 380N, 381, 392, 410, 425, 430, 1752, 4510, 6919, 9076, 9077, W909, W935, W940, W961, W966, W969, W972, W980, W985, W995, W996, W9010, Dynwet800, Siclean3700, UV3500, UV3510, UV3570, etc; 4047, 4060, 4080, 7462, 4020, 4050, 4055, 4300, 4310, 4320, 4400, 4401, 4402, 4403, 4300, 4320, 4330, 4340, 5066, 5220, 6220, 6225, 6230, 6700, 6780, 6782, 8503; manufactured by BASF Japan, JONCRYL (registered trademark) (hereinafter the same) 67, 678, 586, 611, 680, 682, 690, 819, -JDX5050, etc.; manufactured by Otsuka Chemical Co., Ltd., TERPLUS (registered trademark) ( The same applies to the following) MD1000, D1180, D1130, etc.; Ajinomoto Fine-Techno Co., Ltd., AJISPER (registered trademark) (the same applies hereinafter) PB-711, PB-821, PB-822, etc.; Kusumoto Chemical Co., Ltd., DISPARON ( Registered trademark) (hereinafter the same) 1751N, 1831, 1850, 1860, 1934, DA-400N, DA-703-50, DA-325, DA-375, DA-550, DA-705, DA-725, DA- 1401, DA-7301, DN-900, NS-5210, NVI-8514L, etc.; manufactured by Toagosei Corporation, ARUFON (registered trademark) (hereinafter the same) UC-3000, UF-5022, UG-4010, UG-4035, UG-4070 etc.

(3) Crushing and dispersing method

The method for dispersing the composite tungsten oxide fine particles in the dispersion liquid is not particularly limited on the premise that the composite tungsten oxide fine particles can be uniformly dispersed in the dispersion liquid without agglomeration. However, the crystal structure of the pulverized and composite tungsten oxide microparticles is required to be able to be prepared to ensure that the a-axis is within the range of 7.3850Å or more and 7.4186Å or less, and the c-axis is within the range of 7.5600Å or more and 7.6240Å or less, and the composite tungsten oxide can be prepared. The average particle diameter of the fine particles is 100 nm or less, preferably 10 nm or more and 100 nm or less, more preferably 10 nm or more and 80 nm or less, and particularly preferably 10 nm or more and 60 nm or less.

For example, pulverization and dispersion treatment methods using devices such as bead mills, ball mills, sand mills, paint shakers, and ultrasonic homogenizers can be mentioned. Among them, the time required for pulverization and dispersion by medium stirring mills such as bead mills, ball mills, sand mills, and paint shakers using media media such as ball beads, grinding balls, and Ottawa sand until the desired dispersion particle size is achieved. Shorter is better.

By pulverizing and dispersing with a medium stirring mill, the composite tungsten oxide fine particles are dispersed in the dispersion liquid, and the collision between the composite tungsten oxide fine particles or the collision of the fine particles with a medium is also used. The fine particles of the composite tungsten oxide can be made into fine particles and dispersed (that is, subjected to pulverization and dispersion treatment).

At this time, from the viewpoint of exhibiting excellent infrared absorption properties, the fine particles of the composite tungsten oxide that have been micronized and dispersed have a lattice constant of 7.3850 Å or more and 7.4186 Å or less for the a-axis system and 7.5600 Å or more and 7.6240 Å or less for the c-axis system. , and the grain size is preferably 10 nm or more and 100 nm or less, more preferably 10 nm or more and 80 nm or less, and particularly preferably 10 nm or more and 60 nm or less, the grinding and dispersion treatment conditions are adjusted.

By the mechanical dispersion treatment process using these equipment, while the composite tungsten oxide particles are dispersed in the solvent, the composite tungsten oxide particles collide with each other to promote micronization, and the composite tungsten oxide is oxidized. The hexagonal crystal structure contained in the object particles imparts strain or deformation, changes the overlapping state of electron orbits in atoms constituting the crystal structure, and increases the amount of free electrons.

In addition, the micronization of the composite tungsten oxide particles and the fluctuation of the a-axis length and the c-axis length, which are lattice constants in the hexagonal crystal structure, vary depending on the device constant of the pulverizing device. Therefore, it is important to perform experimental pulverization in advance, and to obtain a pulverizing device and pulverizing conditions that can impart predetermined average particle diameter, crystal grain diameter, and a-axis length and c-axis length of lattice constant to the composite tungsten oxide fine particles .

When dispersing the composite tungsten oxide fine particles in the plasticizer, it is also a preferable configuration to further add an organic solvent having a boiling point of 120° C. or lower as necessary.

Specific examples of the organic solvent having a boiling point of 120° C. or lower include toluene, methyl ethyl ketone, methyl isobutyl ketone, butyl acetate, isopropanol, and ethanol. In particular, it can be arbitrarily selected on the premise that the boiling point is 120° C. or lower and the fine particles exhibiting the near-infrared absorption function can be uniformly dispersed. However, when the organic solvent is added, the drying step is performed after the dispersion is completed, and the organic solvent remaining in the infrared light absorbing layer described later as an example of the near-infrared absorbing fine particle dispersion is preferably 5 mass % or less. The reason is that if the residual solvent in the infrared light absorbing layer is 5 mass % or less, the agricultural and horticultural soil mulching film described later does not generate air bubbles, and good appearance and optical properties can be maintained.

The state of the composite tungsten oxide fine particle dispersion liquid can be confirmed by measuring the dispersion state of the composite tungsten oxide fine particles when the tungsten oxide fine particles are dispersed in a solvent. For example, the composite tungsten oxide microparticles of the present invention can be confirmed by sampling a sample from a solution in which the microparticles and the microparticles are aggregated in a solvent, and then measuring using various commercially available particle size distribution meters. As a particle size distribution analyzer, a well-known measuring apparatus, such as ELS-8000 by Otsuka Electronics Co., Ltd. whose principle is the dynamic light scattering method, can be used.

(4) Dispersed particle size

In the composite tungsten oxide fine particle dispersion liquid of the present invention, the dispersed particle diameter of the composite tungsten oxide fine particles is preferably 200 nm or less, and more preferably 200 nm or less and 1 nm or more.

The reason is that when the finally obtained agricultural and horticultural soil mulching film is provided with a white light reflection layer, the infrared light absorption layer must consider the transparency of visible light by visual observation. That is, the infrared light absorbing layer is required to efficiently absorb near infrared rays while maintaining the transparency of visible light.

Furthermore, because the near-infrared absorbing component containing the composite tungsten oxide fine particles of the present invention will largely absorb light in the near-infrared region, especially in the vicinity of wavelengths of 900 to 2200 nm, the penetrating hue under the visible light will vary from blue to blue. The case where the line is changed to a green line.

On the other hand, if the dispersed particle size of the composite tungsten oxide particles contained in the infrared absorbing layer is 1 to 200 nm, the visible light with wavelengths of 380 nm to 780 nm will not be scattered due to geometric scattering or Mie scattering. Therefore, reducing the coloration of the infrared absorption layer due to light scattering can increase the transmittance of visible light. In addition, in the Rayleigh scattering region, since the scattered light system decreases in proportion to the sixth power of the dispersed particle diameter, the scattering decreases and the transparency is improved as the dispersed particle diameter decreases. Therefore, when the dispersion particle size is set to be 200 nm or less, the scattered light is very small, and the transparency can be further increased, which is preferable.

From the above, when the dispersed particle size of the fine particles is less than 200 nm, transparency can be ensured, and when this transparency is important, the dispersed particle size is preferably 150 nm or less, more preferably 100 nm or less. On the other hand, if the dispersed particle size is 1 nm or more, industrial production is easy.

Here, the dispersed particle size of the composite tungsten oxide fine particles in the composite tungsten oxide fine particle dispersion liquid will be briefly described. The "dispersed particle size" refers to the particle size of the individual particles of the composite tungsten oxide fine particles dispersed in the solvent, or the aggregated particles aggregated by the composite tungsten oxide fine particles, and can be measured by various commercially available particle size distribution meters. For example, a sample of the composite tungsten oxide fine particle dispersion liquid can be taken and measured using ELS-8000 manufactured by Otsuka Electronics Co., Ltd. whose principle is the dynamic light scattering method.

Furthermore, the composite tungsten oxide fine particle dispersion liquid obtained by the above-mentioned synthesis method in which the content of the composite tungsten oxide fine particles is 0.01 mass % or more and 80 mass % or less is excellent in system liquid stability. When an appropriate liquid medium, or dispersant, coupling agent, and surfactant are selected, even when placed in a thermostatic bath at a temperature of 40°C, the dispersion will not gel or precipitate for more than 6 months. , the dispersed particle size can be maintained in the range of 1~200nm.

In addition, the dispersed particle diameter of the composite tungsten oxide fine particle dispersion liquid may be different from the dispersed particle diameter of the composite tungsten oxide fine particles dispersed in the composite tungsten oxide fine particle dispersion. This phenomenon is because even if the composite tungsten oxide fine particle agglomeration occurs in the composite tungsten oxide fine particle dispersion liquid, when the composite tungsten oxide fine particle dispersion liquid is processed into the composite tungsten oxide fine particle dispersion liquid, the agglomeration of the composite tungsten oxide fine particle will not occur. was dissolved. However, the smaller the dispersed particle size of the composite tungsten oxide fine particle dispersion, the smaller the dispersed particle size of the near-infrared absorbing fibers. Therefore, the control of the dispersed particle size of the composite tungsten oxide fine particle dispersion is a matter of It is important to control the properties of the near-infrared absorbing fibers obtained in the subsequent steps.

(5) Binder and other additives

In this composite tungsten oxide fine particle dispersion liquid, one or more kinds selected from resin binders may be appropriately contained. The type of resin binder contained in the composite tungsten oxide fine particle dispersion is not particularly limited, and thermoplastic resins such as acrylic resins, thermosetting resins such as epoxy resins, and the like can be appropriately used.

Furthermore, in order to improve the near-infrared absorption properties of the composite tungsten oxide fine particle dispersion of the present invention, the general formula XBm (wherein the X series alkaline earth element, or a compound containing an Metal elements selected from the rare earth elements; 4≦m≦6.3) borides or near-infrared absorbing fine particles such as ATO or ITO are also preferred. In addition, the addition ratio at this time may be appropriately selected according to the desired near-infrared absorption characteristics.

Furthermore, in order to adjust the color tone of the composite tungsten oxide fine particle dispersion, a well-known inorganic pigment such as carbon black and red dandelion, or a well-known organic pigment may be added.

A known ultraviolet absorber, a known organic infrared absorber, or a phosphorus-based anti-coloring agent may be added to the composite tungsten oxide fine particle dispersion.

[d] Soil mulching film for agriculture and horticulture

The agricultural and horticultural soil mulching film of the present invention will be described.

Generally, the solar rays reaching the surface are in the wavelength range of 290-2100 nm. Among them, light with a wavelength of about 380~780nm visible light wavelength region is necessary for the growth of plants. Therefore, the light in the visible light wavelength region with a wavelength of about 380-780 nm is preferably reflected, and only selectively and efficiently absorbs the near-infrared light with a wavelength of about 780-2100 nm to reflect the visible light necessary for plant growth on the plant side, And absorb the infrared light that will become hot to warm the soil, and the ambient temperature in the greenhouse will not rise.

The agricultural and horticultural soil mulching film of the present invention may, for example, have a structure in which infrared absorbing material fine particles are coated on at least one side of the agricultural and horticultural soil mulching film and an infrared light absorbing layer is provided, or may be used in the agricultural and horticultural soil mulching film. The inside of the film of the soil covering film has a structure in which fine particles of the infrared absorbing material are dispersed and present.

The agricultural and horticultural soil mulching film of the present invention may further be provided with a white light reflection layer in which a white light reflection material is dispersed.

In addition, the film having the white reflective layer may be coated with the infrared absorbing material fine particles and the infrared light absorbing layer may be coated on at least one side of the film; the white light reflective material and the infrared absorbing material fine particles may be dispersed in Inside the film, a white light reflecting layer and an infrared light absorbing layer are formed.

Furthermore, a white light reflective layer coated with a white light reflective material may be provided on one side of the film, and the white light reflective layer may have a structure in which infrared absorbing material fine particles are coated and an infrared light absorbing layer is provided.

Furthermore, a white light reflective layer coated with a white light reflective material may be provided on one side of the film, and an infrared light absorbing layer coated with infrared absorbing material fine particles may be provided on the other side of the film.

Furthermore, in the above configuration, since the infrared light absorbing layer does not have coloration caused by the infrared absorbing material particles, even if a white reflective layer is further provided, the white reflective layer of the agricultural and horticultural soil mulching film of the present invention will not be affected by infrared rays. Colored by the light absorbing layer.

The agricultural and horticultural soil mulching film of the present invention absorbs the solar heat formed by the sunlight through the infrared absorbing material particles, and the film absorbs infrared rays to increase the temperature of the film, thereby increasing the radiant heat. As a result, the internal temperature of the soil covered with the agricultural and horticultural soil mulching film rapidly rises, but the ambient temperature in the greenhouse does not rise. In addition, since visible light is reflected by the white light-reflecting material of the agricultural and horticultural soil mulching film of the present invention, the amount of visible light hitting the plants increases, and the photosynthetic amount increases, thereby promoting plant growth.

The applicable method of the infrared absorbing material microparticles of the present invention is to first disperse the microparticles in a suitable medium, and then coat the medium in which the microparticles have been dispersed on the surface of a desired substrate to form an infrared light absorbing layer. In this method, the infrared absorbing material microparticles obtained by calcining at high temperature in advance can be kneaded into the film substrate, or can be bonded to the surface of the substrate by using a binder. As a result, it can be applied to substrate materials with low heat-resistance temperature such as resin materials, and a large-scale device is not required for the formation of the infrared light absorbing layer, which has the advantage of being inexpensive.

Furthermore, since the infrared absorbing material fine particles of the present invention are conductive materials, when the fine particles are connected to form a continuous film, they may absorb and reflect radio waves from mobile phones or the like, which may interfere. However, when the infrared absorbing material is dispersed in the matrix in the form of fine particles, since the fine particles of the infrared absorbing material are dispersed one by one in an isolated state, the radio wave transmittance can be exerted and it is versatile.

As described above, when the infrared absorbing material particles are coated on one side of the film substrate with the white light reflective material dispersed therein to form an infrared light absorbing layer; When a white light reflective layer is coated, and the infrared absorbing material particles are coated on the white light reflective layer to form an infrared light absorbing layer; when a white light reflective material is coated on one side of the film substrate to form a white light reflective layer, and the When coating the infrared absorbing material fine particles on the other side to form an infrared light absorbing layer, in the above case, for example, if the infrared absorbing material fine particles are dispersed in a suitable solvent, after adding a resin binder, the film is coated on the surface of the film substrate , the solvent is evaporated, and then the resin is hardened according to a predetermined method to form an infrared light absorbing layer film in which the infrared absorbing material particles are dispersed in the medium.

The method of applying the infrared absorbing material fine particles to the surface of the film base material is not particularly limited as long as the resin containing the infrared absorbing material fine particles can be uniformly coated on the film base material surface. Preferred systems include, for example, bar coating, gravure coating, spray coating, dip coating, flow coating, spin coating, roll coating, screen printing, blade coating, etc. . In addition, if a coating liquid in which the infrared absorbing material fine particles are directly dispersed in the binder resin is used, it is not necessary to evaporate the solvent after the coating liquid is applied to the surface of the film substrate, which is environmentally friendly and industrial. better.

The above-mentioned resin binder can be selected according to the purpose, for example: UV curing resin, thermosetting resin, electron beam curing resin, room temperature curing resin, thermoplastic resin and the like.

Specifically, for example, polyethylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl alcohol resin, polystyrene resin, polypropylene resin, ethylene vinyl acetate copolymer, polyester resin, polypara Ethylene phthalate resin, fluororesin, polycarbonate resin, acrylic resin, polyvinyl butyral resin.

In addition, a binder using a metal alkoxide can also be used. The metal alkoxides are represented by alkoxides such as Si, Ti, Al, and Zr. The binder system using this metal alkoxide can form an oxide film by hydrolysis and heating.

Furthermore, as described above, the infrared absorbing material fine particles may be dispersed in the inside of the film base material in which the white light reflecting material is dispersed.

Specifically, the fine particles may be permeated from the surface of the film base material, or the base material resin may be heated to a melting temperature or higher to be melted, and then the infrared absorbing material fine particles and the melted base resin may be fused together. mix. Alternatively, a heat ray absorbing component-containing master batch containing the fine particles at a high concentration in the base material resin may be prepared in advance, and then the master batch may be diluted and adjusted to a predetermined concentration.

The resin containing the infrared absorbing material fine particles obtained as described above can be used as an infrared absorbing material by molding it into a film shape according to a predetermined method.

The above-mentioned master batch containing a heat ray absorbing component will be further explained.

The production method of the master batch is not particularly limited, and for example, the composite tungsten oxide fine particle dispersion, the powder or particle of the thermoplastic resin, and other additives as needed are mixed using a ribbon blender, Rotating drum, Nauta Mixer, Henschel mixer, rapid mixing granulator, planetary mixer and other mixers, and Bamburi mixer, kneader, drum, kneading rudder, single-shaft extrusion It is possible to prepare a molten mixture in which the above-mentioned fine particles are uniformly dispersed in the thermoplastic resin by uniformly melt-mixing with a kneader such as a kneader and a twin-screw extruder, while removing the solvent.

On the other hand, the solvent of the composite tungsten oxide fine particle dispersion liquid is removed by a known method, and the obtained composite tungsten oxide fine particle powder, thermoplastic resin powder or particle, and other additives as needed are uniformly melt-mixed. The method can also prepare a molten mixture in which the composite tungsten oxide microparticles are uniformly dispersed in the thermoplastic resin.

Furthermore, a method of preparing a molten mixture by directly adding the powder of the composite tungsten oxide fine particles to the thermoplastic resin and uniformly mixing it can also be employed.

The molten mixture obtained by the above method is kneaded with a vented single-screw or twin-screw extruder, and processed into pellets to obtain a heat ray absorbing component-containing master batch.

The method of dispersing the infrared absorbing material fine particles in the resin is not particularly limited, but preferably, for example, ultrasonic dispersion, a medium stirring mill, a ball mill, a sand mill, and the like can be used.

The fine particle dispersion medium used in the above-mentioned dispersion operation is not particularly limited. The medium resin binder to be mixed can be selected, and various general organic solvents such as water, alcohols, ethers, esters, ketones, and aromatic compounds can be used. Moreover, you may adjust pH by adding acid or alkali as needed. Moreover, in order to further improve the dispersion stability of the infrared absorbing material fine particles, various surfactants, coupling agents, etc. may be added.

The white light-reflecting material used in the agricultural and horticultural soil mulching film of the present invention is not particularly limited. Specifically, preferable examples are TiO ₂ , ZrO ₂ , SiO ₂ , Al ₂ O ₃ , MgO, ZnO, CaCO ₃ , BaSO ₄ , ZnS, PbCO ₃ and the like. These white light-reflecting materials may be used alone or in combination of two or more.

The film used for the agricultural and horticultural soil mulching film of the present invention is not particularly limited. Specifically, preferable examples include polyethylene, polypropylene, polyethylene terephthalate, polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, tetrafluoroethylene-ethylene copolymer, poly Chlorotrifluoroethylene, trifluorotetrachloroethylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polystyrene, ethylene vinyl acetate, polyester resin, etc. To these resins, additives such as stabilizers, stabilizers, antioxidants, plasticizers, lubricants, and ultraviolet absorbers may be further added.

As described in detail above, the agricultural and horticultural soil mulching film of the present invention is a film provided with an infrared light absorbing layer containing fine particles of an infrared absorbing material, and further provided with a white light reflecting layer containing a white light reflecting material.

The agricultural and horticultural soil mulching film of the present invention has high weather resistance and low cost, and can efficiently absorb near-infrared rays from sunlight with a small amount of particles of the infrared absorbing material. Furthermore, when a white light reflection layer is further provided, a soil covering film for agriculture and horticulture that reflects visible light can be provided.

When the agricultural and horticultural soil mulching film of the present invention is used on the ground of cultivated plants, etc., the temperature of the covered ground rises to warm the soil, and there is an effect that the ambient temperature in a greenhouse or the like does not rise. In addition, when a white light reflection layer is further provided, it can reflect light in the visible wavelength region required for plant growth, and also has the effect of promoting plant growth, which is extremely useful.

[Example]

Hereinafter, an Example is given and this invention is demonstrated more concretely. However, the present invention is not limited to this.

Furthermore, the crystal structure, lattice constant and crystal grain diameter of the composite tungsten oxide fine particles of the present invention are measured using composite tungsten oxide fine particles obtained by removing the solvent from the composite tungsten oxide fine particle dispersion. The X-ray diffraction pattern of the composite tungsten oxide fine particles was obtained by using a powder X-ray diffraction apparatus (X'Pert-PRO/MPD manufactured by Spectris PANalytical) according to the powder X-ray diffraction method (θ-2θ). method) to measure. From the obtained X-ray diffraction pattern, the crystal structure contained in the fine particles was specified, and the lattice constant and the crystal grain diameter were further calculated using the Rittwald method.

[Example 1]

In 6.70 kg of water, 7.43 kg of cesium carbonate (Cs ₂ CO ₃ ) was dissolved to obtain a solution. This solution was added to 34.57 kg of tungstic acid (H ₂ WO ₄ ), and after stirring and mixing well, drying was performed while stirring (the molar ratio of W and Cs corresponds to 1:0.33). The dried product was heated while supplying 5 vol % H ₂ gas using N ₂ gas as a carrier gas, and calcined at a temperature of 800° C. for 5.5 hours. Then, the supply gas was switched to N ₂ gas only, the temperature was lowered to room temperature, and composite tungsten oxide particles were obtained.

ZrO₂球珠的塗料振盪機(淺田鐵工公司製)中，藉由施行10小時粉碎、分散處理，而製備得實施例1的複合鎢氧化物微粒子分散液。此時，相對於該混合物100質量份，使用300質量份的0.3mm

ZrO₂球珠施行粉碎、分散處理。 Weighing: 10% by mass of the composite tungsten oxide particles, an acrylic polymer dispersant having an amine-containing functional group (an acrylic dispersant with an amine value of 48 mgKOH/g and a decomposition temperature of 250°C) (hereinafter referred to as "dispersion"). agent a") 10% by mass and 80% by mass of toluene, loaded into a 0.3 mm

The composite tungsten oxide fine particle dispersion liquid of Example 1 was prepared by performing pulverization and dispersion treatment in a paint shaker (manufactured by Asada Iron Works) of ZrO ₂ balls for 10 hours. At this time, with respect to 100 parts by mass of the mixture, 300 parts by mass of 0.3 mm was used

ZrO ₂ balls are crushed and dispersed.

Here, the dispersed particle size of the composite tungsten oxide fine particles in the composite tungsten oxide fine particle dispersion liquid was measured using an ELS-8000 manufactured by Otsuka Electronics Co., Ltd., and the fluctuation of the scattered light of the laser was observed, and the dynamic light scattering method (photon correlation method) was used. [Spectrum] method, photon correlation spectroscopy) to obtain the autocorrelation function, and the average particle diameter (hydrodynamic diameter) was calculated by the accumulation method, and the result was 70 nm.

In addition, regarding the setting of particle diameter measurement, the particle refractive index was set to 1.81, and the particle shape was set to be non-spherical. In addition, the background system was measured using toluene, and the solvent refractive index system was set to 1.50.

Furthermore, after removing the solvent from the composite tungsten oxide fine particle dispersion, the lattice constants of the obtained composite tungsten oxide fine particles were measured, and the a-axis was 7.4071 Å and the c-axis was 7.6188 Å. In addition, the crystal grain diameter is 24 nm. Furthermore, a hexagonal crystal structure was confirmed. The above manufacturing conditions and measurement results are shown in Table 1. In addition, in Table 1, the manufacturing conditions and measurement results of Examples 2 to 19 described later are also described together.

The optical properties, visible light transmittance and near-infrared absorption properties of the composite tungsten oxide fine particle dispersion were measured using a spectrophotometer U-4100 manufactured by Hitachi, Ltd. The measurement was carried out by filling a solution of the composite tungsten oxide fine particle dispersion with toluene into a glass cell for measurement of a spectrophotometer. In addition, the dilution by this toluene is implemented so that the visible light transmittance of the composite tungsten oxide fine particle dispersion liquid after dilution becomes about 70%.

In this measurement, the light incident direction of the spectrophotometer was set to be a direction perpendicular to the glass cell for measurement.

In addition, the light transmittance measurement was also performed with respect to the blank liquid containing only the toluene of the dilution solvent in the glass tank for this measurement, and the measurement result was made into the base line of the light transmittance.

50 parts by mass of the composite tungsten oxide fine particle dispersion liquid of Example 1 and 30 parts by mass of the ultraviolet curable resin for hard coating (solid content 100%) were mixed to obtain an infrared absorbing material fine particle dispersion liquid. The obtained infrared absorbing material fine particle dispersion liquid was coated on a polyethylene film containing TiO ₂ fine particles of a white light reflecting material using a bar coater to form a film. The film was dried at 60° C. for 30 seconds to evaporate the solvent, and then cured with a high-pressure mercury lamp to obtain the infrared absorbing film of Example 1 with a high diffuse reflectance in the visible light region.

In Example 1, the infrared absorbing layer is an infrared absorbing film provided on a thin film. Hereinafter, the same applies to Examples 2 to 19 and Comparative Examples 1 to 9.

The average particle diameter of the composite tungsten oxide fine particles dispersed in the infrared absorbing film obtained in Example 1 was calculated by an image processing apparatus using a transmission electron microscope image. Accordingly, the average particle diameter of the fine particles is 25 nm, which is almost the same value as the above-mentioned crystal grain diameter of 24 nm.

Furthermore, the optical properties of the infrared absorbing film obtained in Example 1 were measured using a spectrophotometer U-4100 manufactured by Hitachi, Ltd., using the transmittance of light with a wavelength of 200 to 2600 nm, and calculated according to JIS A 5759:2016. Output visible light transmittance, solar transmittance, visible light reflectance, solar reflectance, solar absorptivity (here, the solar absorptivity is determined by the solar absorptivity (%) = 100% - insolation transmittance (%) - insolation reflectance (%) is calculated).

The results are shown in Table 2. In addition, the results obtained in Examples 2 to 19 are also described together in Table 2.

[Examples 2 to 11]

Except for the tungstic acid and cesium carbonate described in Example 1, or the aqueous solution of ammonium metatungstate (50 wt % based on WO ₃ ) and cesium carbonate, the molar ratio of W and Cs is 1:0.21~0.37. The infrared absorbing films of Examples 2 to 11 were obtained in the same manner as in Example 1 except that the predetermined amount was weighed.

The evaluation similar to Example 1 was performed about the optical characteristic of the infrared absorption film of the obtained Example 2-11. In addition, a hexagonal crystal structure was confirmed in any composite tungsten oxide fine particle sample. The manufacturing conditions and evaluation results of these Examples are described in Tables 1 and 2.

[Example 12]

Except that in the production of composite tungsten oxide particles described in Example 1, while supplying 5% H ₂ gas with N ₂ gas as a carrier gas, and calcining at a temperature of 550 ° C for 9.0 hours, the rest were carried out and carried out. In the same manner as in Example 1, the infrared absorbing film of Example 12 was obtained.

The optical properties of the infrared absorbing film of Example 12 obtained were evaluated in the same manner as in Example 1. In addition, the composite tungsten oxide fine particle sample had a hexagonal crystal structure confirmed. The manufacturing conditions and evaluation results of these Examples are described in Tables 1 and 2.

[Example 13]

Toluene was removed from the composite tungsten oxide fine particle dispersion liquid described in Example 1 using a spray dryer to obtain a composite tungsten oxide fine particle dispersion powder of Example 13.

20 parts by mass of the obtained composite tungsten oxide fine particle dispersion powder was added to 80 parts by mass of polyethylene resin particles, uniformly mixed with a blender, melt-kneaded with a twin-screw extruder, and then the extruded strands were mixed. It was cut into pellets to obtain a master batch containing composite tungsten oxide fine particles.

Similarly, TiO ₂ : 10 parts by mass was added to 90 parts by mass of polyethylene resin pellets, uniformly mixed with a blender, melt-kneaded with a twin-screw extruder, and the extruded strands were cut into In granular form, a _TiO2 -containing masterbatch is obtained.

The obtained master batch containing composite tungsten oxide fine particles, 50 parts by mass of the master batch containing TiO ₂ , and 50 parts by mass of the master batch without adding inorganic fine particles which were melt-kneaded in the same manner were mixed. This mixed master batch was subjected to extrusion molding to form a 50 μm thick film of Example 13. The evaluation similar to Example 1 was performed about the optical characteristic of this film. In addition, the composite tungsten oxide fine particle sample had a hexagonal crystal structure confirmed.

The evaluation results are shown in Table 2.

[Example 14]

50 parts by mass of the composite tungsten oxide fine particle dispersion described in Example 1 and 30 parts by mass of the ultraviolet curable resin for hard coating (solid content 100%) were mixed to obtain an infrared absorbing material fine particle dispersion.

Similarly, 50 parts by mass of TiO ₂ fine particles and 30 parts by mass of ultraviolet curable resin for hard coating (solid content 100%) were mixed to obtain a white light reflecting material fine particle dispersion liquid containing TiO ₂ fine particles.

The obtained infrared absorbing material fine particle dispersion liquid was coated on a polyethylene film using a bar coater to form a film. The film was dried at 60° C. for 30 seconds to evaporate the solvent, and then cured by a high-pressure mercury lamp. Then, on the other side of the polyethylene film, the white light-reflecting material fine particle dispersion liquid was coated in the same way to form a film, and then hardened to form the film of Example 14 with high diffuse reflectance in the visible light region. The evaluation similar to Example 1 was performed about the optical characteristic of this film. In addition, the composite tungsten oxide fine particle sample had a hexagonal crystal structure confirmed.

The evaluation results are shown in Table 2.

[Examples 15 to 19]

A solution was obtained by dissolving 5.56 kg of rubidium carbonate (Rb ₂ CO ₃ ) in 6.70 kg of water. This solution was added to 36.44 kg of tungstic acid (H ₂ WO ₄ ), and after stirring and mixing sufficiently, drying was performed while stirring to obtain the dried product of Example 15 (the molar ratio of W and Rb is equivalent to 1:0.33). ).

A solution was obtained by dissolving 0.709 kg of cesium carbonate (Cs ₂ CO ₃ ) and 5.03 kg of rubidium carbonate (Rb ₂ CO ₃ ) in 6.70 kg of water. This solution was added to 36.26 kg of tungstic acid (H ₂ WO ₄ ), and after stirring and mixing sufficiently, drying was performed while stirring to obtain the dried product of Example 16 (the molar ratio of W and Cs was equivalent to 1:0.03). , the molar ratio of W and Rb is equivalent to 1:0.30).

In 6.70 kg of water, 4.60 kg of cesium carbonate (Cs ₂ CO ₃ ) and 2.12 kg of rubidium carbonate (Rb ₂ CO ₃ ) were dissolved to obtain a solution. This solution was added to 35.28 kg of tungstic acid (H ₂ WO ₄ ), and after stirring and mixing sufficiently, drying was performed while stirring to obtain the dried product of Example 17 (the molar ratio of W and Cs is equivalent to 1:0.20). , the molar ratio of W and Rb is equivalent to 1:0.13).

In 6.70 kg of water, 5.71 kg of cesium carbonate (Cs ₂ CO ₃ ) and 1.29 kg of rubidium carbonate (Rb ₂ CO ₃ ) were dissolved to obtain a solution. This solution was added to 35.00 kg of tungstic acid (H ₂ WO ₄ ), and after stirring and mixing sufficiently, drying was performed while stirring to obtain the dried product of Example 18 (the molar ratio of W and Cs is equivalent to 1:0.25). , the molar ratio of W and Rb is equivalent to 1:0.08).

In 6.70 kg of water, 6.79 kg of cesium carbonate (Cs ₂ CO ₃ ) and 0.481 kg of rubidium carbonate (Rb ₂ CO ₃ ) were dissolved to obtain a solution. This solution was added to 34.73 kg of tungstic acid (H ₂ WO ₄ ), and after stirring and mixing sufficiently, drying was performed while stirring to obtain the dried product of Example 19 (the molar ratio of W and Cs was equivalent to 1:0.30). , the molar ratio of W and Rb is equivalent to 1:0.03).

The obtained dried products of Examples 15 to 19 were heated while supplying 5% H ₂ gas with N ₂ gas as carrier gas, and calcined at a temperature of 800° C. for 5.5 hours, and then the supply gas was switched to N only. _2. The gas was cooled to room temperature to obtain the composite tungsten oxide particles of Examples 15 to 19.

Except that the composite tungsten oxide particles of Example 1 were replaced by the composite tungsten oxide particles of Examples 15 to 19, the same operations as in Example 1 were performed to obtain infrared absorbing films of Examples 15 to 19. .

The optical properties of the infrared absorbing films of Examples 15 to 19 were evaluated in the same manner as in Example 1. In addition, a hexagonal crystal structure was confirmed in any composite tungsten oxide fine particle sample.

The manufacturing conditions and evaluation results are shown in Tables 1 and 2.

[Comparative Examples 1 to 3]

Except that the tungstic acid and cesium carbonate were changed as follows: a predetermined amount was weighed so that the molar ratio of W and Cs was 1:0.11 (Comparative Example 1), and the molar ratio of W and Cs was 1:0.15 (Comparative Example 2). A predetermined amount of weighing was carried out in such a manner that the molar ratio of W and Cs was 1:0.39 (Comparative Example 3), and the predetermined amount of weighing was carried out.

Other than that, the same operation as in Example 1 was performed, and the infrared absorbing films of Comparative Examples 1 to 3 were obtained.

The optical properties of the infrared absorbing films of Comparative Examples 1 to 3 were evaluated in the same manner as in Example 1.

The manufacturing conditions and evaluation results are shown in Tables 3 and 4.

[Comparative Examples 4 and 5]

Except that the tungstic acid and cesium carbonate were changed as follows: a predetermined amount was weighed so that the molar ratio of W and Cs was 1:0.21 (Comparative Example 4), and the molar ratio of W and Cs was 1:0.23 (Comparative Example 5). The same operation as in Example 1 was performed except that a predetermined amount was weighed and calcined at a temperature of 400° C. for 5.5 hours, and the infrared absorbing films of Comparative Examples 4 and 5 were obtained.

The optical properties of the infrared absorbing films of Comparative Examples 4 and 5 were evaluated in the same manner as in Example 1.

The manufacturing conditions and evaluation results are shown in Tables 3 and 4.

[Comparative Example 6]

In the production of the composite tungsten oxide particle dispersion in Example 1, the rotation speed of the paint shaker was set to 0.8 times that of Example 1, and the pulverization and dispersion treatment was performed for 100 hours, and the rest were performed as in Example 1. By the same operation, the infrared absorbing film of Comparative Example 6 was obtained.

The optical properties of the infrared absorbing film of Comparative Example 6 were evaluated in the same manner as in Example 1.

The manufacturing conditions and evaluation results are shown in Tables 3 and 4.

[Comparative Example 7]

In the production of the composite tungsten oxide particles of Example 1, calcination was performed at a temperature of 440° C. for 5.5 hours while supplying 3 vol% H ₂ gas with N ₂ gas as a carrier gas, and the rest were carried out as in Example 1. By the same operation, the infrared absorbing film of Comparative Example 7 was obtained.

The optical properties of the infrared absorbing film of Comparative Example 7 were evaluated in the same manner as in Example 1.

The manufacturing conditions and evaluation results are shown in Tables 3 and 4.

[Comparative Example 8]

Except for weighing: composite tungsten oxide particles of Example 1: 10 mass %, dispersant a: 10 mass %, and toluene: 80 mass %, and mixing by ultrasonic vibration for 10 minutes, the rest were carried out and carried out. In the same manner as in Example 1, the composite tungsten oxide fine particle dispersion liquid and the infrared absorbing film of Comparative Example 8 were obtained. That is, the composite tungsten oxide particles contained in the composite tungsten oxide fine particle dispersion liquid of Comparative Example 8 were not pulverized.

The optical properties of the infrared absorbing film of Comparative Example 8 were evaluated in the same manner as in Example 1.

The manufacturing conditions and evaluation results are shown in Tables 3 and 4.

[Comparative Example 9]

For the composite tungsten oxide particles of Example 1, the rotation speed of the paint shaker was set to 1.15 times that of Example 1, and pulverization and dispersion treatment were performed for 25 hours, the same operation as Example 1 was performed. The composite tungsten oxide fine particle dispersion liquid and the infrared absorbing film of Comparative Example 9 were obtained.

The optical properties of the infrared absorbing film of Comparative Example 9 were evaluated in the same manner as in Example 1.

The manufacturing conditions and evaluation results are shown in Tables 3 and 4.

[in conclusion]

From the results of Tables 1, 2 and 3 and 4, it can be known that the infrared absorbing films of Examples 1 to 19 can effectively block sunlight, especially the infrared absorbing films of Comparative Examples 1 to 9. It captures light in the near-infrared region while maintaining high transmittance in the visible light region.

It is known from Tables 2 and 4 that if the Examples 1 to 19 are compared with Comparative Examples 1 to 5, it is found that the infrared light absorbing layer formed by coating the composite tungsten oxide fine particles is formed in the thin film with dispersed particles. On the thin film of the white light reflective material, the infrared light absorption rate of the thin film can be greatly increased, and visible light can be reflected, and the heat storage property is excellent. That is, it is known that in Examples 1 to 19, the reflectance of visible light can be maintained at nearly 6 to 70%, and the solar absorptivity can be increased to about 4 to 60%.

The agricultural and horticultural soil mulching films of Examples 1 to 19 are films including a white light reflective layer containing a white light reflective material and an infrared light absorbing layer containing fine particles of an infrared absorbing material.

Specifically, the white light-reflecting layer is a thin film in which a white light-reflecting material is dispersed, and is: a thin film consisting of an infrared light absorbing layer formed by coating infrared absorbing material particles on one side of the thin film; or White light-reflecting material and infrared absorbing material particles are dispersed inside the film to form a film composed of a white light-reflecting layer and an infrared-absorbing layer; A reflective layer and a thin film composed of an infrared light absorbing layer formed by coating infrared absorbing material particles on the white light reflective layer; layer, and a thin film composed of an infrared light absorbing layer formed by coating the other side of the thin film with infrared absorbing material particles.

With the above-mentioned simple structure, forming an infrared light absorbing layer containing fine particles of infrared absorbing material, preferably composite tungsten oxide fine particles, can provide good weather resistance, low cost, and can absorb efficiently with a small amount of fine particles. A soil mulch film for agriculture and horticulture that reflects the near-infrared rays of sunlight and reflects visible light.

Claims (18)

An agricultural and horticultural soil mulching film, which is an agricultural and horticultural soil mulching film having an infrared light absorbing layer containing infrared absorbing material fine particles, characterized in that the infrared absorbing material fine particles are composite tungsten oxide fine particles containing a hexagonal crystal structure; The lattice constant of the above-mentioned composite tungsten oxide fine particles is 7.3850Å or more and 7.4186Å or less, and the c-axis is 7.5600Å or more and 7.6240Å or less; the average particle size of the above composite tungsten oxide fine particles is 10nm or more and 100nm or less; The crystal grain diameter of the composite tungsten oxide fine particles is 10 nm or more and 100 nm or less. The agricultural and horticultural soil mulch film according to claim 1, wherein the lattice constants of the composite tungsten oxide fine particles are 7.4031 Å or more and 7.4111 Å or less on the a-axis, and 7.5891 Å or more and 7.6240 Å or less on the c-axis. The agricultural and horticultural soil mulching film according to claim 1, wherein the composite tungsten oxide fine particles are dispersed in the resin binder of the infrared light absorbing layer provided on at least one side of the agricultural and horticultural soil mulching film. The agricultural and horticultural soil mulching film according to claim 1, wherein the composite tungsten oxide fine particles are dispersed inside the film of the agricultural and horticultural soil mulching film. The agricultural and horticultural soil mulching film according to claim 1, wherein the composite tungsten oxide microparticles are of the general formula M _x W _y O _z (wherein M element is selected from H, He, alkali metals, alkaline earth metals, rare earth elements , Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb , B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Hf, Os, Bi, I, one or more selected elements; W is tungsten; O is oxygen ; 0.001≦x/y≦1, 2.0≦z/y≦3.0) composite tungsten oxide fine particles. The agricultural and horticultural soil mulching film according to claim 5, wherein the M element is one or more elements selected from Cs and Rb. The agricultural and horticultural soil mulching film according to any one of claims 1 to 6, wherein at least a part of the surface of the composite tungsten oxide fine particles is made of a material containing at least one or more selected from Si, Ti, Zr, and Al. The surface of the element is covered with a film. The agricultural and horticultural soil covering film according to claim 7, wherein the surface covering film system contains oxygen atoms. The agricultural and horticultural soil mulching film of claim 1, wherein the film is made of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, tetrafluoroethylene At least one selected from ethylene-ethylene copolymer, polychlorotrifluoroethylene, trifluorotetrachloroethylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polystyrene, ethylene vinyl acetate, and polyester resin above. The agricultural and horticultural soil mulching film of claim 1, wherein a white light reflection layer in which a white light reflective material is dispersed is provided inside the film of the agricultural and horticultural soil mulching film. The agricultural and horticultural soil mulching film according to claim 1, comprising: a white light reflective layer coated with a white light reflective material on one side of the agricultural and horticultural soil mulching film, and a white light reflective layer coated on the white light reflective layer An infrared light absorbing layer with particles of infrared absorbing material; or a white light reflective layer coated with a white light reflective material on one side of the above-mentioned agricultural and horticultural soil mulching film, and on the other side of the above-mentioned agricultural and horticultural soil mulching film An infrared light absorbing layer coated with fine particles of an infrared absorbing material. The agricultural and horticultural soil mulching film according to claim 10 or 11, wherein the white light-reflecting material is made of TiO ₂ , ZrO ₂ , SiO ₂ , Al ₂ O ₃ , MgO, ZnO, CaCO ₃ , BaSO ₄ , ZnS, PbCO Select at least one of ₃ . A method for producing an agricultural and horticultural soil mulching film, which is a method for producing an agricultural and horticultural soil mulching film provided with an infrared light absorbing layer containing infrared absorbing material fine particles, wherein the infrared absorbing material fine particles contain a hexagonal crystal structure. composite tungsten oxide fine particles; the composite tungsten oxide fine particles are manufactured in such a way that the a-axis of the lattice constant is 7.3850Å or more and 7.4186Å or less, and the c-axis is 7.5600Å or more and 7.6240Å or less; while maintaining the above The above-mentioned range of the lattice constant of the composite tungsten oxide fine particles is performed while the average particle diameter is 10 nm or more and 100 nm or less, and the crystal grain diameter is 10 nm or more and 100 nm or less. The method for producing a soil mulching film for agriculture and horticulture according to claim 13, wherein the composite tungsten oxide fine particles are of the general formula M _x W _y O _z (wherein M element is selected from H, He, alkali metals, alkaline earth metals, Rare earth elements, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, One or more elements selected from Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Hf, Os, Bi, and I; W is tungsten; O-based oxygen; 0.001≦x/y≦1, 2.0≦z/y≦3.0) composite tungsten oxide fine particles. The method for producing an agricultural and horticultural soil mulching film according to claim 14, wherein the M element is one or more elements selected from Cs and Rb. The method for producing an agricultural and horticultural soil mulching film according to any one of claims 13 to 15, wherein at least a part of the surface of the composite tungsten oxide fine particles is made of at least one selected from the group consisting of Si, Ti, Zr, and Al. The surface coating film of one or more elements is covered. The method for producing an agricultural and horticultural soil covering film according to claim 16, wherein the surface covering film contains oxygen atoms. The method for producing an agricultural and horticultural soil mulching film according to claim 13, wherein the film of the agricultural and horticultural soil mulching film contains polyethylene, polypropylene, polyethylene terephthalate, polyvinyl fluoride, polyethylene Vinylidene fluoride, polytetrafluoroethylene, tetrafluoroethylene-ethylene copolymer, polychlorotrifluoroethylene, trifluorotetrachloroethylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polystyrene, vinyl acetate A film of one or more resins selected from vinyl ester and polyester resins.

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