Infrared cutoff film

• US 6,528,156 B1
• Filed: 06/09/2000
• Issued: 03/04/2003
• Est. Priority Date: 10/16/1998
• Status: Expired due to Term

• Current Assignee: Tomoegawa Paper Company Limited
• Original Assignee: Tomoegawa Paper Company Limited
• Inventors: Takahashi, Shinichi, Takizawa, Tuyoshi
• Primary Examiner(s): Resan, Stevan A.
• Assistant Examiner(s): Uhlir, Nikolas J.
• Application Number:
  US09/581,088
• Time in Patent Office: 998 Days
• Field of Search: 428/323, 428/328, 428/402, 428/688, 428/689, 428/413, 428/522
• US Class Current: 428/323
• CPC Class Codes: C09D 5/32 Radiation-absorbing paints protection against X-, gamma- or corpuscular radiation G21F
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/256 Heavy metal or aluminum or compound thereof
• CPC Class Codes: Y10T 428/31511 Of epoxy ether
• CPC Class Codes: Y10T 428/31935 Ester, halide or nitrile of addition polymer

Abstract

An infrared cut-off layer containing an ITO powder is formed on one surface of a base film, to form an infrared cut-off film. The ITO powder has a minimum value of a diffused-reflection-functional logarithm, logf(R_d), at a light wavelength of 470 nm or lower, which logarithm is measured on the basis of the following equation, f(R_d)=(1−R_d)²/2R_d=α/S (R_d: a relative reflectance to a standard sample, α: an absorption coefficient, S: a scattering coefficient, formulated for a diffused reflection light, and the minimum value of −0.1 or less. There is provided an infrared cut-off film having a hue of blue and sufficient transparency.

Claims

1. An infrared cut-off film having an infrared cut-off layer which is formed on a film by using a coating composition obtained by mixing and dispersing a powder of indium tin oxide in a resin having transparency,

wherein the powder of indium tin oxide has a minimum value of a diffused-reflection-functional logarithm, logf(R_d)), at a light wavelength of 470 nm or lower, which logarithm is measured on the basis of the following equation formulated for a diffused reflection light,

2. The infrared cut-off film according to claim 1, wherein the powder of indium tin oxide has a molar ratio of 0.5 to 10 of oxygen per 100 of indium.

3. The infrared cut-off film according to claim 1, wherein the powder of indium tin oxide has a molar ratio of 5 to 10 of tin and 0.5 to 10 of oxygen per 100 of indium.

4. The infrared cut-off film according to claim 1, wherein the applied layer has a thickness of 0.5 to 10 μ

m.

5. The infrared cut-off film according to claim 1, where in the coating composition has an indium tin oxide/resin weight ratio in the range of 90/10 to 60/40.

6. The infrared cut-off film according to claim 1, wherein the coating composition in which the powder of indium tin oxide is mixed and dissolved further contains a pigment having an average particle diameter of 100 nm or less.

7. The infrared cut-off film according to claim 1, wherein the powder of indium tin oxide has an average particle diameter of 100 nm or less.