Heat ray cutting film and method for producing same, and laminated glass and heat ray cutting member
The present invention provides a heat ray cutting film comprising, on a substrate, at least two layers of a light reflecting layer X1 and a light reflecting layer X2 obtained by fixing cholesteric liquid crystalline phases, and an infrared ray absorbing layer comprising composite tungsten oxide microparticles, wherein the light reflecting layer X1 and the light reflecting layer X2 reflect lights circularly polarized in directions opposite to each other, reflection center wavelengths of the light reflecting layer X1 and the light reflecting layer X2 are within a range of 800 to 1100 nm and are substantially equal to each other, and total reflectivity of all light reflecting layers obtained by fixing cholesteric liquid crystalline phases is 80% or more. The heat ray cutting film of the present invention has high transparency and high heat shielding performance.
1. A heat ray cutting film comprising a substrate, a light reflecting layer X1, a light reflecting layer X2, and an infrared ray absorbing layer in this order,
the infrared ray absorbing layer comprising composite tungsten oxide microparticles,
each of the light reflecting layer X1 and the light reflecting layer X2 being a layer obtained by fixing cholesteric liquid crystalline phase,
the light reflecting layer X1 and the light reflecting layer X2 reflecting lights circularly polarized in directions opposite to each other, and
reflection center wavelengths of the light reflecting layer X1 and the light reflecting layer X2 being substantially equal to each other within a range of 800 to 1100 nm,
wherein the number of light reflecting layers is 2 or 3,
wherein maximum reflectivity in 800 to 1100 nm of all light reflecting layers obtained by fixing cholesteric liquid crystalline phases is 80% or more,
wherein the substrate and the light reflecting layer X1 are directly in contact and the light reflecting layer X2 and the infrared ray absorbing layer are directly in contact,
(i) the light reflecting layer X1 and the light reflecting layer X2 are directly in contact; or
(ii) the heat ray cutting film further comprises a light reflecting layer X3 made of a single layer wherein the light reflecting layer X3 is a layer obtained by fixing cholesteric liquid crystalline phase, the light reflecting layer X1 and the light reflecting layer X3 are directly in contact, and the light reflecting layer X3 and the light reflecting layer X2 are directly in contact, and
wherein the light reflecting layer X3 reflects light circularly polarized in the same direction as the light reflecting layer X1, and reflection center wavelength of the light reflecting layer X3 is within a range of 800 to 1400 nm.
2. The heat ray cutting film according to claim 1 , wherein the light reflecting layer X1 reflects right circularly-polarized light and the light reflecting layer X2 reflects left circularly-polarized light.
3. The heat ray cutting film according to claim 1 , wherein the substrate is a plastic substrate.
4. The heat ray cutting film according to claim 1 , wherein the composite tungsten oxide is represented by general formula (1) below:
M x WO y
M represents at least one kind selected from the group consisting of Cs, Na, Rb, K, Tl,In, Ba, Li, Ca, Sr, Fe and Sn, 0.1≦×≦0.5, and 2.2≦y≦3.0.
5. The heat ray cutting film according to claim 1 , wherein the average particle diameter of the composite tungsten oxide microparticles is 5 to500 nm.
6. The heat ray cutting film according to claim 1 , wherein the infrared ray absorbing layer is a layer obtained by dispersing the composite tungsten oxide microparticles in an ultraviolet curable resin or a thermoplastic resin.
7. The heat ray cutting film according to claim 1 , further comprising an adhering layer comprising polyvinyl butyral resin.
8. The heat ray cutting film according to claim 7 , wherein the adhering layer comprises at least one kind of ultraviolet ray absorbers.
9. A laminated glass comprising two glass plates and the heat ray cutting film according to claim 1 sandwiched between the two glass plates.
10. A method of producing the heat ray cutting film according to claim 1 , comprising a step of forming the light reflecting layer X1 by applying a curable liquid crystal composition comprising a curable cholesteric liquid crystal compound on a surface of the substrate, drying the applied curable liquid crystal composition, and progressing a curing reaction of the curable liquid crystal composition, and
a step of forming the infrared ray absorbing layer by applying an application liquid comprising composite tungsten oxide microparticles on a surface of the light reflecting layer X2.
11. The method of producing a heat ray cutting film according to claim 10 , comprising a step of forming the light reflecting layer X2 by applying a curable liquid crystal composition comprising a curable cholesteric liquid crystal compound on a surface of the light reflecting layer X1, drying the applied curable liquid crystal composition, and progressing a curing reaction of the curable liquid crystal composition.
12. The method of producing a heat ray cutting film according to claim 10 , comprising a step of forming the light reflecting layer X2 by applying a curable liquid crystal composition comprising a curable cholesteric liquid crystal compound on a light reflecting layer X3 made of a single layer that is provided on a surface of the light reflecting layer X1, drying the applied curable liquid crystal composition, and progressing a curing reaction of the curable liquid crystal composition.
13. The heat ray cutting film according to claim 1 , wherein the heat ray cutting film has a haze value of 1% or less.
14. The heat ray cutting film according to claim 1 , wherein the heat ray cutting film has a visible light transmittance of 70% or more.
15. The heat ray cutting film according to claim 1 , wherein the heat ray cutting film has a transmittance at 850 nm of 10% or less.
16. The heat ray cutting film according to claim 1 , wherein the average particle diameter of the composite tungsten oxide microparticles is 5 to 30 nm.