Radar transmissive pigments, coatings, films, articles, method of manufacture thereof, and methods of use thereof

Patent metadata

Field	Value
Publication number	US-2023399516-A1
Application number	US-202118004693-A
Country	US
Kind code	A1
Filing date	Jul 8, 2021
Priority date	Jul 9, 2020
Publication date	Dec 14, 2023
Grant date	—

Abstract

Radar transmissive pigments, coatings, films, articles, method of manufacture thereof, and methods of use thereof are provided. The pigment comprises a non-conductive composite. The non-conductive composite comprises a semiconductor and/or a dielectric, and a metal dispersed in and/or on the semiconductor and/or dielectric. The pigment has an aspect ratio of at least 5 as measured by the Aspect Ratio Test.

First claim

1 . A pigment comprising:
a non-conductive composite comprising:
a semiconductor and/or a dielectric, and
a metal dispersed in and/or on the semiconductor and/or dielectric,
wherein the pigment has an aspect ratio of at least 5, wherein the aspect ratio is an average lateral size of the pigment divided by an average thickness of the pigment.

2 . The pigment of claim 1 , wherein the non-conductive composite is formed from a non-homogenous mixture.

3 . The pigment of claim 1 , wherein the metal is present in an amount of 1 wt % to 50 wt % based on the total weight of the non-conductive composite.

4 . The pigment of claim 1 , wherein the pigment has an average reflectance of at least 60% across a visible wavelength range of 400 nm to 700 nm as measured using an integrating sphere spectrophotometer averaging the reflectance values over the visible wavelength range of 400 to 700 nm for both the specular component included (SCI) mode and the specular excluded (SCE) mode, and then subtracting the average reflectance in the SCE mode from the average reflectance in the SCI mode.

5 . The pigment of claim 1 , wherein the metal has an average particle size in a range of 0.5 nm to 100 nm as measured by transmission electron microscopy, and/or the metal is dispersed in an organic, inorganic, or organic-inorganic hybrid material.

6 . The pigment of claim 1 , wherein the pigment has an average thickness in a range of 1 nm to 20 microns as measured with a transmission electron microscope for a thickness of less than 5 microns or an optical microscope for a thickness of at least 5 microns, and/or an average lateral size in a range of 5 microns to 150 microns, as measured with an optical microscope.

7 . The pigment of claim 1 , wherein the metal comprises aluminum, silver, copper, indium, tin, nickel, titanium, gold, iron, an alloy of any thereof, or combinations thereof.

8 . The pigment of claim 1 , wherein the non-conductive composite comprises a semiconductor comprising silicon, germanium, silicon carbide, boron nitride, aluminum nitride, gallium nitride, silicon nitride, gallium arsenide, indium phosphide, indium nitride, indium arsenide, indium antimonide, zinc oxide, zinc sulfide, zinc telluride, tin sulfide, bismuth sulfide, nickel oxide, boron phosphide, titanium dioxide, barium titanate, iron oxide, doped versions thereof, alloys thereof, or combinations thereof, such as, silicon.

9 . The pigment of claim 1 , wherein the non-conductive composite comprises a dielectric comprising solid insulator materials, ceramics, glass, organic materials, doped versions thereof, or combinations thereof.

10 . The pigment of claim 1 , wherein the semiconductor and/or dielectric is resistant to melting.

11 . The pigment of claim 1 , wherein the semiconductor and/or dielectric to metal weight ratio in the non-conductive composition is in a range of 1:1 to 9:1.

12 . The pigment of claim 1 , wherein the non-conductive composite has a resistivity of at least 1 Ohm cm as measured according to a four-point probe at ambient temperature.

13 . The pigment of claim 1 , wherein the pigment has or is made to have surface functionality that imparts a property to the pigment.

14 . The pigment of claim 1 , wherein the non-conductive composite does not comprise a thermoplastic resin nor a material that is predominantly amorphous carbon.

15 . A method of making the pigment of claim 1 , the method comprising:
depositing the metal and semiconductor and/or dielectric utilizing sputtering onto a support to form a non-conductive composite layer; mixing the metal and the semiconductor and/or dielectric to form the non-conductive composite layer; and/or depositing the semiconductor and/or dielectric to form a first layer and adding the metal to the first layer to form the conductive composite layer.

16 . The method of claim 15 , wherein the metal is added to the first layer in a predetermined pattern as non-continuous layer.

17 . The method of claim 15 , wherein the metal is added to the first layer as a continuous layer.

18 . The method of claim 15 , wherein the non-conductive composite is deposited directly onto the support, a release layer that has been applied to the support, or a soluble film.

19 . The method of claim 18 , wherein, after depositing the non-conductive support onto a release layer or a soluble film, the release layer or soluble film is dissolved by treatment or immersion in solvent, thereby releasing the non-conductive composite from the support.

20 . The method of claim 15 , further comprising processing the non-conductive composite to an average lateral size in a range of 5 microns to 150 microns as measured with an optical microscope.

21 . A coating composition comprising:
the pigment of claim 1 ; and a film-forming resin.

22 . (canceled)

23 . A film comprising the pigment of claim 1 .

24 . A coating layer comprising the pigment of claim 1 or a film comprising the pigment of claim 1 , when applied to a substrate, wherein the coating layer or film comprises:
a. an L 15 value of at least 50 as measured using a multi-angle spectrophotometer at the measurement angle of 15° relative to the specular direction, with D65 illumination and 10° observer;
b. a flop index of at least 4 as measured using a multi-angle spectrophotometer, with D65 illumination and 10° observer according to the following equation:
Flop Index=2.69( L 15 −L 110 ) 1.11 /( L 45 ) 0.86

wherein:
L 15 is CIE L* value measured at the aspecular angle of 15°;
L 45 is CIE L* value measured at the aspecular angle of 45°; and
L 110 is CIE L* value measured at the aspecular angle of 110°;

c. one-way radar transmission loss of no greater than 1.5 dB as measured using a radar transmission system at a wavelength in a range of 76 GHz to 81 GHz; and
d. at least 90% opacity as measured using an integrating sphere spectrophotometer with D65 illumination, observer, and specular component included.

25 . An article comprising:
the pigment of claim 1 ; a coating layer comprising the pigment of claim 1 ; and/or a film comprising the pigment of claim 1 .

26 . (canceled)

27 . The article of claim 25 , wherein the article comprises:
a. an L 15 value of at least 50 as measured using a multi-angle spectrophotometer at the measurement angle of 15° relative to the specular direction, with D65 illumination and 10° observer; b. a flop index of at least 4 as measured using a multi-angle spectrophotometer, with D65 illumination and 10° observer according to the following equation:
Flop Index=2.69( L 15 −L 110 ) 1.11 /( L 45 ) 0.86
wherein:
L 15 is CIE L* value measured at the aspecular angle of 15°;
L 45 is CIE L* value measured at the aspecular angle of 45°; and
L 110 is CIE L* value measured at the aspecular angle of 110°;
c. one-way radar transmission loss of no greater than 1.5 dB as measured using a radar transmission system at a wavelength in a range of 76 GHz to 81 GHz; and d. at least 90% opacity as measured using an integrating sphere spectrophotometer with D65 illumination, observer, and specular component included.

28 . A substrate coated or covered at least in part with a coating composition comprising the pigment of claim 1 or a film comprising the pigment of claim 1 .

29 . (canceled)

Assignees

• Ppg Ind Ohio Inc

Inventors

• Moravek Scott J
• Decker Eldon L
• Munro Calum H
• Fenn David R
• Duarte Nicolas B
• Connor Daniel
• Sun Hao

Classifications

• C09C1/0078 Primary

  Pigments consisting of flaky, non-metallic substrates, characterised by a surface-region containing free metal · CPC title

• C09C3/066

  Treatment or coating resulting in a free metal containing surface-region (C09C1/0078 takes precedence) · CPC title

• C09D5/028

  Pigments; Filters · CPC title

• C01P2004/54

  Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension · CPC title

• C01P2006/60

  Optical properties, e.g. expressed in CIELAB-values · CPC title