Radar frequency transparent effect pigment mixture, formulations and coatings thereof

Patent metadata

Field	Value
Publication number	US-11421111-B2
Application number	US-202017602475-A
Country	US
Kind code	B2
Filing date	Apr 9, 2020
Priority date	Apr 12, 2019
Publication date	Aug 23, 2022
Grant date	Aug 23, 2022

Abstract

This invention deals with effect pigment mixture comprising platelet-like aluminum effect pigments obtained by grinding of aluminum or aluminum based alloy shot and silvery pearlescent pigments, wherein the silvery pearlescent pigments are taken from the group consisting of: a) pearlescent pigments comprising a transparent substrate which is coated with a high-refractive index layer with n>1.8, which comprises or consists of an iron-oxide with Fe(II)-ions, b) pearlescent pigments comprising a transparent substrate which is coated with a high-refractive index layer with n>1.8, which comprises or consists of titanium suboxide or a pearlescent pigment comprising a substrate with a high-refractive index with n>1.8 layer, which comprises or consists of a titanium suboxide that is optionally coated with a high-refractive index layer with n>1.8, c) pearlescent pigments comprising a transparent substrate which is coated with a high-refractive index layer with n>1.8, which comprises or consists of titanium oxynitride, d) pearlescent pigments comprising a transparent substrate which is coated with a layer comprising carbon, wherein the carbon is enclosed in a particulate form in another metal oxide layer or is formed as a separate, individual layer, e) a transparent substrate coated with a first layer comprising or consisting of a mixture of the oxides of titanium, iron and at least one of cobalt and chromium and a second layer on the first layer, wherein the second layer comprises an oxide of titanium, and mixtures or combinations of the pearlescent pigments a) to e) or pearlescent pigments with mixtures or combinations of the various coating layers mentioned in the pearlescent pigments a) to e), wherein the weight ratio of the pearlescent pigment to the aluminum effect pigment is in a range of 0.4 to 5.0. The invention deals also with a coating formulation containing this effect pigment mixture.

First claim

The invention claimed is:

1. An effect pigment mixture comprising a silvery pearlescent pigment and platelet-like aluminum effect pigment, the aluminum effect pigment obtained by grinding of one or more of aluminum shot or aluminum based alloy shot, wherein the silvery pearlescent pigment comprises any one or more of:
a) a pearlescent pigment comprising a transparent substrate coated with a high-refractive index layer having n>1.8 and comprising an iron-oxide including Fe(II)-ions,
b1) a pearlescent pigment comprising a transparent substrate coated with a high-refractive index layer having n>1.8 and comprising a titanium suboxide,
b2) a pearlescent pigment comprising a substrate including a high-refractive index layer having n>1.8 and comprising a titanium suboxide that is optionally coated with a high-refractive index layer having n>1.8,
c) a pearlescent pigment comprising a transparent substrate coated with a high-refractive index layer having n>1.8 and comprising a titanium oxynitride,
d) a pearlescent pigment comprising a transparent substrate coated with a layer comprising carbon, wherein the carbon is enclosed in a particulate form in another metal oxide layer or is formed as a separate, individual layer,
e) a pearlescent pigment comprising a transparent substrate coated with a first layer comprising a mixture of oxides of titanium, iron and at least one of cobalt and chromium and a second layer on the first layer, wherein the second layer comprises an oxide of titanium, and
f) a pearlescent pigment comprising any one of the coating layers mentioned in the pearlescent pigments a) to e),
wherein the weight ratio of the pearlescent pigment to the aluminum effect pigment is in a range of 0.4 to 5.0.

2. The effect pigment mixture according to claim 1 , wherein the platelet-like aluminum effect pigment has a d 50 ranging from 9 to 30 μm.

3. The effect pigment mixture according to claim 1 , wherein the platelet-like aluminum effect pigments have a mean thickness h m ranging from 80 to 500 nm.

4. The effect pigment mixture according to claim 1 , wherein the platelet-like aluminum effect pigment is coated with an anticorrosive coating comprising adsorbed additives based on one or more of a phosphonic acid, a phosphoric ester, a metal oxide, and a polymer.

5. The effect pigment mixture according to claim 4 , wherein the metal oxide includes any one or more of SiO 2 , Ce-oxide, Mo-oxide, V-oxide, and Cr-oxide.

6. The effect pigment mixture according to claim 1 , wherein the platelet-like aluminum effect pigment comprises a mixture of finer and of coarser metallic effect pigments, wherein the finer aluminum effect pigments have a d 50 ranging from 9 to 13 μm and the coarser aluminum effect pigments have a d 50 ranging from 18 to 26 μm.

7. The effect pigment mixture according to claim 1 , wherein the silvery pearlescent pigments comprise any one or more of:
a) the pearlescent pigment of type a), wherein the pearlescent pigment includes a coating comprising a metal oxide layer comprising Ti- and Fe-ions, wherein the Fe-ions are mainly Fe(II) ions,
b) one or more of the pearlescent pigment pigments of type b1) and b2), wherein the titanium suboxide is represented by the formula
Ti n O 2n-1   (IV)

wherein n in an integer of 1 to 10,
c) the pearlescent pigment of type c), wherein the titanium oxynitride is represented by the formula
Ti x N y O z   (V)

wherein x is 0.2 to 0.6, y is 0.05 to 0.6 and z is 0.1 to 0.9, which comprises a solid solution of nitrogen in titanium monoxide, and
f) pearlescent pigments comprising any one or more of the coating layers mentioned in the pearlescent pigments of types a) to c).

8. The effect pigment mixture according to claim 1 , wherein the silvery pearlescent pigment comprises the pearlescent pigment of type a comprising the following structure:
(a) a transparent platelet-shaped synthetic substrate,
(b) a titanium oxide layer, followed by
(c) a metal oxide layer comprising Ti- and Fe-ions, wherein the Fe-ions are mainly Fe(II)-ions.

9. The effect pigment mixture according to claim 7 , wherein the silvery pearlescent pigment has an iron/titanium weight ratio as a function of the coating, in accordance with formula (I)

Iron
⁢

⁢
content
⁢

⁢

(

wt
.

-
%

)

Titanium
⁢

⁢
content
⁢

⁢

(

wt
.

-
%

)

×
Fraction
⁢

⁢

⁢
of
⁢

⁢
the
⁢

⁢
coating
⁢

⁢

(

wt
.

-
%

)

(
III
)

is in a range from 1 to 8,
wherein “iron content” represents the amount of iron compounds, calculated as elemental iron, and “titanium content” represents the amount of titanium compounds, calculated as elemental titanium, in each case in the pigment and based on the total weight of the pigment, and where the “fraction of the coating (% by weight)” represents the weight fraction, based on the total weight of the pigment, of the coating applied to the substrate.

10. The effect pigment mixture according to claim 1 , wherein the chrom

Assignees

• Eckart Gmbh

Inventors

• Brendel Carolin
• Greiwe Klaus
• Maul Robert
• Bedford Oliver
• Kaupp Günter

Classifications

• C09C2200/00

  Compositional and structural details of pigments exhibiting interference colours · CPC title

• C09C1/0015

  Pigments exhibiting interference colours, e.g. transparent platelets of appropriate thinness or flaky substrates, e.g. mica, bearing appropriate thin transparent coatings · CPC title

• C09C1/0081

  Composite particulate pigments or fillers, i.e. containing at least two solid phases, except those consisting of coated particles of one compound (C09C1/0015, C09C1/0078 take precedence) · CPC title

• C09C2200/1054

  the core consisting of a metal · CPC title

• C01P2006/62

  L* (lightness axis) · CPC title