TECHNICAL FIELD

The present invention relates to a solar radiation shielding laminated structure used for a window material or the like for a vehicle such as a car, for a building, and for an airplane, and a process for producing the same.

DESCRIPTION OF RELATED ART

Conventionally, as a glass used for a window material or the like for a car, a building, or the like, laminated glass formed by sandwiching solar radiation shielding layer between two pieces of sheet-glass, which shields the incident solar energy to reduce cooling load and heat sensation has been proposed.

For example, Patent Document 1 proposes a laminated glass in which a soft resin layer is interposed between two pieces of sheet-glass, and ITO or ATO as a heat ray shielding metal oxide is contained and dispersed.

On the other hand, the present applicants disclose, in Patent Document 2, a solar radiation shielding laminated glass in which an interlayer having a solar radiation shielding function is interposed between two pieces of sheet-glass, the interlayer containing hexaboride fine particles alone or hexaboride fine particles, ITO fine particles and/or ATO fine particles, and vinyl resin.

Furthermore, the present applicants disclose, in Patent Document 3, a solar radiation shielding laminated glass containing tungsten oxide fine particles having high transparency and high solar radiation shielding function.

PRIOR ART DOCUMENT

Patent Document

[Patent Document 1] Japanese Patent Laid-Open Publication No. 1996-217500[Patent Document 2] Japanese Patent Laid-Open Publication No. 2001-89202[Patent Document 3] Japanese Patent No. 3985193

Non-Patent Document

[Non-Patent Document 1] Satoshi Yoshio, Koichiro Maki and Kenji Adachi, “Optical properties of group-3 metal hexaboride nanoparticles by first-principles calculations”, J. Chem. Phys., Vol. 144, 234702 (2016)[Non-patent document 2] K. Machida and K. Adachi, “Particle shape inhomogeneity and plasma band broadening of solar-control LaB6 nanoparticles”, J. Appl. Phys., 118, 013103 (2015)[Non-Patent Document 3] Ceramics, 22 volumes, 1987, pp 40-45 by Hiroshi Nishikawa[Non-patent document 4] Powder and industry, 21 (5) 1989 by Doi

SUMMARY OF THE INVENTION

Problem to be Solved by the Invention

As a result of study by the present inventors, the following problems were found.

First, ITO and ATO used for the laminated glass described in Patent Document 1 have a low shielding effect against a near-infrared radiation at a wavelength about 800 to 1000 nm. On the other hand, regarding the solar radiation, since the intensity of the wavelength is high, the laminated glass cannot suppress the scorching sensation to skin. In addition, their raw material, In, is very expensive because of its limited amount, which bottlenecks their popularization.

Secondly, the hexaboride fine particles described in Patent Document 2 are excellent in the ability to absorb the near-infrared radiation at wavelengths from 800 to 900 nm, have a high effect of preventing the scorching sensation to skin, and advantageously achieve an effect even when added in a trace amount because of their high absorption coefficient. However, since their visible light transmission property is slightly inferior at wavelengths other than the green wavelength, they have a disadvantage of giving the glass a greenish color.

Furthermore, tungsten bronze fine particles having a hexagonal crystal structure described in Patent Document 3 are excellent in transparency and near-infrared absorption ability among tungsten oxide fine particles, and achieve high solar radiation shielding property so that the visible light transmittance is 70% and the solar radiation transmittance is 40% or less. However, while the tungsten bronze fine particles have such excellent optical properties, they have environmental instability, for example, they react with moisture, which deteriorates their shielding function. Therefore, they have a disadvantage of involving cost for preventive measures.

The present invention is achieved by focusing on these problems, and an object of the present invention is to provide a solar radiation shielding laminated structure and a method for production thereof, the laminated structure having high visible light transmission property and solar radiation shielding property, low haze value, and high environmental stability and being inexpensive in production cost, using solar radiation shielding fine particles having high visible light transmission property and excellent solar radiation shielding property and having weather resistance.

Means for Solving the Problem

In order to solve the above-described problem, the present inventors conducted intensive research, and obtain finding such that fine particles which are calcium lanthanum boride fine particles having a predetermined shape represented by a general formula CaxLa1-xBm(satisfying 0.001≤x≤0.800, 5.0≤m<6.3) has a strong heat ray absorbing effect and at the same time has a broad visible light transmission property and stable weather resistance. Accordingly, the present inventors found a solar radiation shielding laminated structure, containing the calcium lanthanum boride fine particles as solar radiation shielding fine particles, and thus completed the present invention.

Namely, a first invention to solve the above-described problem provides

a solar radiation shielding laminated structure in which an interlayer is sandwiched between two laminated sheets;the interlayer having, as an intermediate film, one or more kinds selected from a resin sheet containing solar radiation shielding fine particles and a resin film containing solar radiation shielding fine particles,the two laminated sheets being selected from a sheet-glass not containing solar radiation shielding fine particles and a resin board not containing solar radiation shielding fine particles;

wherein the solar radiation shielding fine particles are solar radiation shielding fine particles containing calcium lanthanum boride fine particles represented by general formula CaxLa1-xBm, a value of x is in a range of 0.001≤x≤0.800, and a value of m is in a range of 5.0≤m<6.3 in the general formula,

an average dispersed particle size of the calcium lanthanum boride fine particles is 1 nm or more and 800 nm or less, and

a fine particle shape of the calcium lanthanum boride fine particles is at least one shape selected from the following 1) and 2):1) a shape in which a scattering intensity of the calcium lanthanum boride fine particles diluted and dispersed in a solvent measured using a small-angle X-ray scattering method is such that a slope value Ve of a straight line obtained by double-logarithmic plotting of a relationship between scattering vector q=4π sin θ/λ, and scattering intensity I(q) is in a range of −3.8≤Ve≤−1.5;2) a flat cylindrical (wherein a diameter of a bottom circle is d and a height of a cylinder is h) shape, or a spheroidal (wherein a length of a long axis is d and a length of a short axis is h) shape, with a value of aspect ratio d/h being in a range of 1.5≤d/h≤20.

A second invention provides

a solar radiation shielding laminated structure in which an interlayer is sandwiched between one laminated sheet and another laminated sheet;the interlayer having one or more kinds of intermediate films selected from a resin sheet containing solar radiation shielding fine particles and a resin film containing solar radiation shielding fine particles and one or more intermediate films selected from a resin sheet not containing solar radiation shielding fine particles and a resin film not containing solar radiation shielding fine particles,the one laminated sheet being selected from a sheet-glass not containing solar radiation shielding fine particles, a resin board not containing solar radiation shielding fine particles, and a resin board containing solar radiation shielding fine particles, andthe other laminated sheet including solar radiation shielding fine particles;

wherein the solar radiation shielding fine particles are solar radiation shielding fine particles containing calcium lanthanum boride fine particles represented by general formula CaxLa1-xBm, a value of x is in a range of 0.001≤x≤0.800, and a value of m is in a range of 5.0≤m<6.3 in the general formula,

an average dispersed particle size of the calcium lanthanum boride fine particles is 1 nm or more and 800 nm or less, and

a fine particle shape of the calcium lanthanum boride fine particles is at least one shape selected from the following 1) and 2):1) a shape in which a scattering intensity of the calcium lanthanum boride fine particles diluted and dispersed in a solvent measured using a small-angle X-ray scattering method is such that a slope value Ve of a straight line obtained by double-logarithmic plotting of a relationship between scattering vector q=4π sin θ/λ and scattering intensity I(q) is in a range of −3.8≤Ve≤−1.5;2) a flat cylindrical (wherein a diameter of the bottom circle is d and a height of the cylinder is h) shape, or a spheroidal (wherein a length of a long axis is d and a length of the short axis is h) shape, with a value of aspect ratio d/h being 1.5≤d/h≤20.

A third invention provides

the solar radiation shielding laminated structure according to the first or second invention,

wherein, when solar radiation shielding fine particles are included in two or more of the intermediate film and the laminated sheet, at least one layer includes solar radiation shielding fine particles containing the calcium lanthanum boride fine particles, and at least one of the other layer includes solar radiation shielding fine particles having solar radiation shielding property different from that of the solar radiation shielding fine particles.

A fourth invention provides

the solar radiation shielding laminated structure according to the third invention,

wherein the solar radiation shielding fine particles having solar radiation shielding function different from that of the solar radiation shielding fine particles containing calcium lanthanum boride fine particles are at least one kind of solar radiation shielding fine particles selected from calcium lanthanum boride fine particles having solar radiation shielding function different from that of the calcium lanthanum boride fine particles, hexagonal crystal tungsten bronze fine particles, Sn-doped indium oxide fine particles, Sb-doped tin oxide fine particles, and Al-doped zinc oxide fine particles, and Ga-doped zinc oxide fine particles.

A fifth invention provides

the solar radiation shielding laminated structure according to any one of the first to fourth inventions,

wherein the resin material forming the resin board, resin sheet, and resin film is one kind selected from polycarbonate resin, acrylic resin, and polyethylene terephthalate resin.

A sixth invention provides

the solar radiation shielding laminated structure according to any one of the first to fourth inventions,

wherein the resin material forming the interlayer is vinyl resin.

A seventh invention provides

the solar radiation shielding laminated structure according to the sixth invention,

wherein the vinyl resin is polyvinyl butyral or ethylene-vinyl acetate copolymer.

An eighth invention provides

a method for producing a solar radiation shielding laminated structure in which an interlayer is sandwiched between two laminated sheets;the interlayer having, as an intermediate film, one or more kinds selected from a resin sheet containing solar radiation shielding fine particles and a resin film containing solar radiation shielding fine particles,the laminated sheets being selected from a sheet-glass not containing solar radiation shielding fine particles and a resin board not containing solar radiation shielding fine particles;

wherein the solar radiation shielding fine particles are solar radiation shielding fine particles containing calcium lanthanum boride fine particles represented by general formula CaxLa1-xBm, a value of x is in a range of 0.001≤x≤0.800, and a value of m is in a range of 5.0≤m<6.3 in the general formula,

an average dispersed particle size of the calcium lanthanum boride fine particles is 1 nm or more and 800 nm or less, and

a fine particle shape of the calcium lanthanum boride fine particles is at least one shape selected from the following 1) and 2):1) a shape in which a scattering intensity of the calcium lanthanum boride fine particles diluted and dispersed in a solvent measured using a small-angle X-ray scattering method is such that a slope value Ve of a straight line obtained by double-logarithmic plotting of a relationship between scattering vector q=4π sin θ/λ and scattering intensity I(q) is in a range of −3.8≤Ve≤−1.5;2) a flat cylindrical (wherein a diameter of a bottom circle is d and a height of a cylinder is h) shape, or a spheroidal (wherein a length of a long axis is d and a length of a short axis is h) shape, with a value of aspect ratio d/h being in a range of 1.5≤d/h≤20.

Advantage of the Invention

In the solar radiation shielding laminated structure according to the present invention, the intermediate film and/or laminated sheet includes solar radiation shielding fine particles containing calcium lanthanum boride having a predetermined structure, has high transmission performance in the visible light region, is less colored, has low haze, and, at the same time, has high solar radiation shielding property and excellent weather resistance.

