Lanthanoid-containing inorganic material microparticles, wavelength-converting ink, coated article, and determination apparatus

Patent metadata

Field	Value
Publication number	US-11274248-B2
Application number	US-201716070551-A
Country	US
Kind code	B2
Filing date	Jan 24, 2017
Priority date	Jan 28, 2016
Publication date	Mar 15, 2022
Grant date	Mar 15, 2022

Abstract

A lanthanoid-containing inorganic material fine particle having a function of converting a wavelength of light to a shorter wavelength, the lanthanoid-containing inorganic material fine particle including: a core particle; and a shell layer, the core particle containing a lanthanoid having a light-absorbing function and a lanthanoid having a light-emitting function, the shell layer including at least an outer shell containing a rare earth element, the total amount of the lanthanoid having a light-absorbing function and the lanthanoid having a light-emitting function in the outer shell being 2 mol % or less based on the amount of the rare earth element contained in the outer shell, the outer shell having a thickness of 2 to 20 nm, the core particle and the shell layer having no interface at a contact face to form a continuous body.

First claim

The invention claimed is:

1. A lanthanoid-containing inorganic material fine particle having a function of converting a wavelength of light to a shorter wavelength, the lanthanoid-containing inorganic material fine particle comprising:
a core particle; and
a shell layer,
the core particle containing a lanthanoid having a light-absorbing function and a lanthanoid having a light-emitting function,
the shell layer comprising at least an outer shell containing a rare earth element,
a total amount of the lanthanoid having a light-absorbing function and the lanthanoid having a light-emitting function in the outer shell being 2 mol % or less based on an amount of the rare earth element contained in the outer shell,
the outer shell having a thickness of 2 to 20 nm,
the core particle and the shell layer having no interface at a contact face to form a continuous body, and
the lanthanoid-containing inorganic material fine particle further having a fatty acid and an organophosphorus compound on a surface of the shell layer.

2. The lanthanoid-containing inorganic material fine particle according to claim 1 ,
wherein the shell layer further comprises an inner shell containing a rare earth element,
an amount of the lanthanoid having a light-absorbing function in the inner shell is 75 mol % or less and an amount of the lanthanoid having a light-emitting function in the inner shell is 2 mol % or less, based on an amount of the rare earth element contained in the inner shell, and
the inner shell and the outer shell have no interface at a contact face to form a continuous body.

3. The lanthanoid-containing inorganic material fine particle according to claim 2 ,
wherein the inner shell has a thickness of 2 to 20 nm.

4. The lanthanoid-containing inorganic material fine particle according to claim 1 ,
wherein the core particle has an average particle size of 5 to 250 nm.

5. The lanthanoid-containing inorganic material fine particle according to claim 1 , containing:
a fluoride containing an alkali metal and a rare earth element; or
a fluoride containing oxygen, an alkali metal and a rare earth element.

6. The lanthanoid-containing inorganic material fine particle according to claim 1 , further comprising a polymer layer containing a polymer and noble metal particles around the shell layer.

7. The lanthanoid-containing inorganic material fine particle according to claim 6 ,
wherein the polymer layer is a polymer brush layer.

8. The lanthanoid-containing inorganic material fine particle according to claim 6 , further comprising
an intermediate layer between the shell layer and the polymer layer.

9. An wavelength conversion ink comprising:
the lanthanoid-containing inorganic material fine particle according to claim 1 ; and
a solvent.

10. The wavelength conversion ink according to claim 9 , which is a security ink.

11. A coated article comprising:
the wavelength conversion ink according to claim 9 ; and
a substrate.

12. A lanthanoid-containing inorganic material fine particle having a function of converting a wavelength of light to a shorter wavelength, the lanthanoid-containing inorganic material fine particle comprising:
a core particle; and
a shell layer,
the core particle containing a lanthanoid having a light-absorbing function and a lanthanoid having a light-emitting function,
the shell layer comprising at least an outer shell containing a rare earth element,
a total amount of the lanthanoid having a light-absorbing function and the lanthanoid having a light-emitting function in the outer shell being 2 mol % or less based on an amount of the rare earth element contained in the outer shell,
the outer shell having a thickness of 2 to 20 nm,
the core particle and the shell layer having no interface at a contact face to form a continuous body, and
the lanthanoid-containing inorganic material fine particle further comprising a polymer layer containing a polymer and noble metal particles around the shell layer.

13. A method for determining authenticity of information printed on a substrate with the wavelength conversion ink according to claim 9 by evaluating an emission spectrum and a printing pattern of the wavelength conversion ink, comprising:
irradiating using an irradiation means for infrared irradiation of a coated article comprising the wavelength conversion ink and the substrate, and
detecting using a detection means for detecting an emission spectrum generated by the infrared irradiation and a printing pattern of the wavelength conversion ink.

Assignees

• Sekisui Chemical Co Ltd

Inventors

• Sasaki Taku
• Wakiya Takeshi
• Oohashi Kenji

Classifications

• B41M3/14

  Security printing {(securities B42D25/29)} · CPC title

• C09K11/025

  non-luminescent particle coatings or suspension media · CPC title

• C09D11/322

  Pigment inks · CPC title

• C09K11/7705 Primary

  with alkali or alkaline earth metals · CPC title

• B42D25/00

  Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof (printing processes to produce identification or security features B41M3/14) · CPC title