U.S. patent application number 14/296401 was filed with the patent office on 2015-12-10 for nickel-free green pigment.
The applicant listed for this patent is Ferro Corporation. Invention is credited to Terry J. Detrie, Hans-Peter Letschert, Stephan Ludwig, George E. Sakoske.
Application Number | 20150353706 14/296401 |
Document ID | / |
Family ID | 53276749 |
Filed Date | 2015-12-10 |
United States Patent
Application |
20150353706 |
Kind Code |
A1 |
Letschert; Hans-Peter ; et
al. |
December 10, 2015 |
NICKEL-FREE GREEN PIGMENT
Abstract
A green pigment is a blend of metal oxides including a [124]
spinel which can contain certain combinations of lithium, sodium,
cobalt, zinc, calcium, magnesium, copper, titanium, manganese, tin,
and germanium, and a [134] spinel which can contain certain
combinations of lithium, sodium, chromium, boron, iron, manganese
aluminum, titanium, tin and germanium. The pigment lacks
nickel.
Inventors: |
Letschert; Hans-Peter;
(Hanau, DE) ; Ludwig; Stephan; (Neuberg
Ravolzhausen, DE) ; Detrie; Terry J.; (Washington,
PA) ; Sakoske; George E.; (Independence, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ferro Corporation |
Mayfield Heights |
OH |
US |
|
|
Family ID: |
53276749 |
Appl. No.: |
14/296401 |
Filed: |
June 4, 2014 |
Current U.S.
Class: |
427/383.1 ;
106/430; 106/440; 524/407 |
Current CPC
Class: |
C01G 49/0027 20130101;
C08K 3/22 20130101; C01G 51/42 20130101; C01P 2006/64 20130101;
C08K 2003/262 20130101; C01G 23/003 20130101; C01P 2004/61
20130101; C08K 2003/2251 20130101; C01G 45/006 20130101; C01P
2002/84 20130101; C09D 7/61 20180101; C01P 2006/66 20130101; C08K
3/2279 20130101; C01B 13/185 20130101; C01P 2006/63 20130101; C01G
23/002 20130101; C01P 2002/32 20130101; C01P 2006/62 20130101; C08K
2003/2241 20130101; C01G 51/006 20130101; C01G 1/02 20130101; C01G
19/006 20130101; C01P 2002/50 20130101; C01G 45/12 20130101; C01G
37/006 20130101 |
International
Class: |
C08K 3/26 20060101
C08K003/26; C08K 3/22 20060101 C08K003/22 |
Claims
1. A nickel-free green pigment comprising a solid solution of first
and second mixed metal oxides, a. the first mixed metal oxide
having a [124] spinel structure, comprising i. at least one element
A selected from the group consisting of lithium and sodium, ii. at
least one element B selected from the group consisting of cobalt,
zinc, calcium, magnesium, and copper, iii. at least one element D
selected from the group consisting of titanium, manganese, tin and
germanium, and b. the second mixed metal oxide having a [134]
spinel structure, comprising i. at least one element A selected
from the group consisting of lithium and sodium, ii. at least one
element C selected from the group consisting of chromium, boron,
iron, manganese and aluminum and, iii. at least one element D
selected from the group consisting of titanium, manganese, tin and
germanium, and c. no nickel.
2. (canceled)
3. The nickel-free green pigment of claim 1, wherein the first
mixed metal oxide has the formula BA(D.sub.3A)O.sub.8.
4. The nickel-free green pigment of claim 1, wherein the second
mixed metal oxide has the formula
A.sub.2(C.sub.2D.sub.2)O.sub.8.
5. A paint or coating including the nickel-free green pigment of
claim 1.
6. The paint or coating of claim 1 having a TSR over black of at
least 15.
7. A plastic composition including the nickel-free green pigment of
claim 1.
8-9. (canceled)
10. The nickel-free green pigment of claim 1 having a reflection of
at least 50% over a wavelength range of 800-1100 nm.
11. The nickel-free green pigment of claim 1 having leachable Ni of
less than 1 ppm according to DIN EN71/3:2013.
12. A method of making a nickel-free green pigment comprising a
solid solution of first and second mixed metal oxides, the method
comprising, a. mixing particles of i. a first mixed metal oxide
having a [124] spinel structure, comprising 1. at least one element
A selected from the group consisting of lithium and sodium, 2. at
least one element B selected from the group consisting of cobalt,
zinc, calcium, magnesium, and copper, 3. at least one element D
selected from the group consisting of titanium, manganese, tin and
germanium, 4. no nickel with ii. a second mixed metal oxide having
a [134] spinel structure, comprising 1. at least one element A
selected from the group consisting of lithium and sodium, 2. at
least one element C selected from the group consisting of chromium,
boron, iron, manganese and aluminum, and, 3. at least one element D
selected from the group consisting of titanium, manganese, tin and
germanium, 4. no nickel, to form a mixture, and b. heating the
mixture at a temperature of 800-1700.degree. C. for a time of 1 to
1000 minutes to form at least one of particles and agglomerates of
a green pigment.
13. The method of claim 12, further comprising cooling the green
pigment to room temperature at a rate of 1-50.degree. C. per
minute.
14. The method of claim 12, further comprising reducing the size of
the pigment particles or agglomerates to a D.sub.50 size of 1-10
microns.
15. (canceled)
16. The method of claim 12, wherein the first mixed metal oxide has
the formula BA(D.sub.3A)O.sub.8.
17. The method of claim 12, wherein the second mixed metal oxide
has the formula A.sub.2(C.sub.2D.sub.2)O.sub.8.
18-25. (canceled)
26. A method of imparting a green color to a substrate, comprising,
a. applying to a substrate and b. firing a nickel-free green
pigment comprising a solid solution of first and second mixed metal
oxides, i. the first mixed metal oxide having a [124] spinel
structure, comprising 1. at least one element A selected from the
group consisting of lithium and sodium, 2. at least one element B
selected from the group consisting of cobalt, zinc, calcium,
magnesium, and copper, 3. at least one element D selected from the
group consisting of titanium, manganese, tin and germanium, and 4.
no nickel, ii. the second mixed metal oxide having a [134] spinel
structure, comprising 1. at least one element A selected from the
group consisting of lithium and sodium, 2. at least one element C
selected from the group consisting of chromium, boron, iron,
manganese and aluminum and, 3. at least one element D selected from
the group consisting of titanium, manganese, tin and germanium, and
4. no nickel.
27. The method of claim 26, wherein the first mixed metal oxide has
the formula BA(D.sub.3A)O.sub.8.
28. The method of claim 26, wherein the second mixed metal oxide
has the formula A.sub.2(C.sub.2D.sub.2)O.sub.8.
29. The method of claim 27, wherein the second mixed metal oxide
has the formula A.sub.2(C.sub.2D.sub.2)O.sub.8.
30. The method of claim 26, wherein the substrate is selected from
the group consisting of paints, curable coatings, inks, plastics,
rubbers, ceramics, enamels, and glasses.
31. A method of imparting a green color to a plastic composition,
comprising, melt mixing a. a plastic composition, with b. a
nickel-free green pigment comprising a solid solution of first and
second mixed metal oxides, i. the first mixed metal oxide having a
[124] spinel structure, comprising 1. at least one element A
selected from the group consisting of lithium and sodium, 2. at
least one element B selected from the group consisting of cobalt,
zinc, calcium, magnesium, and copper, 3. at least one element D
selected from the group consisting of titanium, manganese, tin and
germanium, and 4. no nickel, ii. the second mixed metal oxide
having a [134] spinel structure, comprising 1. at least one element
A selected from the group consisting of lithium and sodium, 2. at
least one element C selected from the group consisting of chromium,
boron, Iron, manganese and aluminum, 3. at least one element D
selected from the group consisting of titanium, manganese, tin and
germanium, and 4. no nickel.
32. The method of claim 31, wherein the first mixed metal oxide has
the formula BA(D.sub.3A)O.sub.8.
33. The method of claim 31, wherein the second mixed metal oxide
has the formula A.sub.2(C.sub.2D.sub.2)O.sub.8.
34. The method of claim 32, wherein the second mixed metal oxide
has the formula A.sub.2(C.sub.2D.sub.2)O.sub.8.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of Invention
[0002] The subject disclosure generally relates to pigment
compositions and method of making pigment compositions.
[0003] This invention relates to a green pigment that lacks nickel
in any form and a method of making it. The pigment is a solid
solution of metal oxides including a [124] spinel which can contain
certain combinations of lithium, sodium, cobalt, zinc, calcium,
magnesium, copper, titanium, manganese, tin, and germanium, and a
[134] spinel which can contain certain combinations of lithium,
sodium, chromium, boron, iron, manganese aluminum, titanium, tin
and germanium.
[0004] The green pigment produces colors similar to nickel
containing green pigments and provides high hue angle and high TSR
(total solar reflectance).
[0005] 2. Description of Related Art
[0006] Pigments are widely used in various applications such as
paints, inks, plastics, rubbers, ceramics, enamels, and glasses.
There are various reasons for using inorganic pigments. Among these
are the coloristic properties of the pigments, their visible as
well as ultraviolet (UV) and infrared (IR) reflectance
characteristics, their light fastness and their high temperature
stability. The high temperature stability is necessary when the
objects being colored are produced at elevated temperatures.
[0007] Pigments exhibit certain colors because they selectively
reflect and absorb certain wavelengths of light. White light is an
approximately equal mixture of the entire visible spectrum of
light. When white light encounters a colored pigment, some
wavelengths are absorbed as they interact with the electronic
structure of the pigment. These interactions are determined by the
chemistry and crystal structure of the pigment. The wavelengths not
absorbed are reflected back to the observer, and this reflected
visible light spectrum creates the appearance of a color. For
example, ultramarine reflects blue light, typically between 400 and
500 nanometers in wavelength, and absorbs visible light of other
wavelengths.
[0008] The appearance of pigments is also dependent upon the
spectrum of the source light. Sunlight has a high color temperature
and a fairly uniform spectrum, and is considered a standard for
white light. Artificial light sources, including fluorescent light,
tend to have great peaks in some regions of their spectrum, and
deep valleys in other regions. Viewed under these conditions,
pigments may exhibit different colors.
SUMMARY
[0009] The following presents a simplified summary of the invention
in order to provide a basic understanding of some aspects of the
invention. This summary is not an extensive overview of the
invention. It is intended to neither identify key or critical
elements of the invention nor delineate the scope of the invention.
Its sole purpose is to present some concepts of the invention in a
simplified form as a prelude to the more detailed description that
is presented later.
[0010] An inorganic pigment in the green color space is the spinel
Ti(Co.sub.x,Ni.sub.y,Zn.sub.z)O8 (x+y+z=2). The disadvantage of
that compound is that the nickel leaches easily, which leads to a
toxic labeling of such pigments.
[0011] Additionally, in the turquoise color space
CoLi(Ti.sub.3Li)O.sub.8 is known as a pigment but it is closer to
blue than green in color shade.
[0012] Accordingly, improvements in nickel-free pigments in the
green color space are needed.
[0013] To the accomplishment of the foregoing and related ends, the
invention, then, comprises the features hereinafter fully described
and particularly pointed out in the claims. The following
description and the annexed drawings set forth in detail certain
illustrative embodiments of the invention. These embodiments are
indicative, however, of but a few of the various ways in which the
principles of the invention can be employed. Other objects,
advantages and novel features of the invention will become apparent
from the following detailed description of the invention when
considered in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 shows a UV-VISONIR Spectra of Inventive
Li.sub.1.5Co.sub.0.5(Ti.sub.2.5Li.sub.0.5Cr)O.sub.8 and Ferro's
Conventional Nickel-containing green pigment (BO3433).
DETAILED DESCRIPTION OF THE INVENTION
[0015] The inventors herein began working systematically to develop
a greener inorganic pigment that is nickel free by changing the
composition of the turquoise CoLi(Ti.sub.3Li)O.sub.8 by
modification of the composition.
Co.sup.IILi.sup.I(Ti.sup.IV.sub.3Li.sup.I)O.sub.8 could be
described as a [124] spinel from the oxidation states of the
involved metals. The general formula of a spinel is
A.sub.2(B.sub.4)O.sub.8, where cation A is in tetrahedral
coordination and cation B is in octahedral coordination. By
changing the ratio of Li and Co in this compound color shade can be
changed but the color is still in the turquoise (bluish) color
range, for example CoLi(Ti.sub.3Li)O.sub.8 to
Co.sub.1.5(Ti.sub.3Li)O.sub.8).
[0016] The spinel structure remains also even if the ratio of the
elements does not exactly fit the theoretical composition. In this
case the electroneutrality is preserved by creating cation or anion
vacancies. These vacancies also influence the color of the spinel.
The inventors have discovered that by reducing the Li content of
CoLi(Ti.sub.3Li)O.sub.8 by 0.5 mol to
CoLi.sub.0.5Me.sub.0.5(Ti.sub.3Li)O.sub.8, where Me is a univalent
metal or metalloid, the color is shifted to the greener color
space.
[0017] It is also possible to incorporate other elements into the
same [124] spinel structure like: Cu, Zn, Mg, and Ca, instead of Co
or Li, such exchange of the elements in the A position of the
spinel resulting in various colors:
CoCu.sub.0.5(Ti.sub.3Li)O.sub.8(dark grey),
Co.sub.0.5Zn.sub.0.5Li(Ti.sub.3Li)O.sub.8 (light turquoise),
Co.sub.0.9Zn.sub.0.1Li(Ti.sub.3Li)O.sub.8 (light turquoise),
Co.sub.0.5Cu(Ti.sub.3Li)O.sub.8 (dark green gray),
Co.sub.0.5Mg.sub.0.5Li(Ti.sub.3Li)O.sub.8 (light turquoise).
However, such trials still do not shift the color into the color
space of the Ni containing series
Ti(Co.sub.x,Ni.sub.y,Zn.sub.z)O.sub.8.
[0018] Beside the [124] spinels also [134] spinels of the general
formula A.sup.I(B.sup.IIIC.sup.IV)O.sub.8 are possible such as:
LiAlMnO.sub.8, LiFeTiO.sub.8 or LiCrTiO.sub.8. The last mentioned
is dirty buff colored.
[0019] The inventors found that the latter compound, which could be
also written as Li.sub.2(Cr.sub.2Ti.sub.2)O.sub.8 could be used to
form solid solutions with the turquoise colored [124] spinel
CoLi(Ti.sub.3Li)O.sub.8 in any ratio. For example a 1:1 solid
solution:
Li.sub.2(Cr.sub.2Ti.sub.2)O.sub.8+CoLi(Ti.sub.3Li)O.sub.8->Li.sub.3Co(-
Ti.sub.5LiCr.sub.2)O.sub.16.dbd.Li.sub.1.5Co.sub.0.5(Ti.sub.2.5Li.sub.0.5C-
r)O.sub.8.
[0020] This last mentioned compound is interesting since it is
colored like the Ni containing
Ti(Co.sub.x,Ni.sub.y,Zn.sub.z)O.sub.4 where x+y+z=2.
[0021] Ferro Corporation's standard nickel-containing pigment
Ti(Co.sub.x,Ni.sub.y,Zn.sub.z)O.sub.6 (x+y+z=2) named BO03433 has a
hue angle of 150.6.degree. whereas the compound
Li.sub.1.5Co.sub.0.5(Ti.sub.2.5Li.sub.0.5Cr)O.sub.8 has a hue angle
of 150.9.degree.. Hence
Li.sub.1.5Co.sub.0.5(Ti.sub.2.5Li.sub.0.5Cr)O.sub.8 is a near
perfect nickel-free substitute for BO3433. Solid solutions of the
[124] spinel CoLi(Ti.sub.3Li)O.sub.8 with [134]
Li.sub.2(Cr.sub.2Ti.sub.2)O.sub.8 spinels produce greener colors
along the lines of Ferro's BO3433 without nickel.
[0022] Accordingly, an embodiment of the invention is a nickel-free
green pigment comprising a solid solution of first and second mixed
metal oxides, (a) the first mixed metal oxide comprising (i) at
least one element A selected from the group consisting of lithium
and sodium, (ii) at least one element B selected from the group
consisting of cobalt, zinc, calcium, magnesium, and copper, and
(iii) at least one element D selected from the group consisting of
titanium, manganese, tin and germanium, (b) a second mixed metal
oxide comprising (i) at least one element A selected from the group
consisting of lithium and sodium, (ii) at least one element C
selected from the group consisting of chromium, boron, iron,
manganese, and aluminum, and (iii) at least one element D selected
from the group consisting of titanium, manganese and germanium, and
(c) no nickel.
[0023] Accordingly, an embodiment of the invention is a pigment
comprising a solid solution of (a) a [124] spinel having the
formula AB(D.sub.3A)O.sub.8, where A is selected from the group
consisting of Li and Na; wherein B is selected from the group
consisting of Co, Zn, Ca, Mg, and Cu; and D is selected from the
group consisting of Ti, Mn, Sn, and Ge) with (b) a [134] spinel
having the formula A.sub.2(C.sub.2D.sub.2)O.sub.8 wherein A is
selected from the group consisting of Li and Na; C is selected from
the group consisting of Cr, B, Fe, and Mn, and D is selected from
the group consisting of Ti, Mn, Sn, and Ge, wherein the pigment
exhibits a hue angle between 120 and 180.degree..
[0024] An embodiment of the invention is a method of making a
nickel-free green pigment comprising a solid solution of first and
second mixed metal oxides, the method comprising, (a) mixing
particles of (i) a first mixed metal oxide comprising (1) at least
one element A selected from the group consisting of lithium and
sodium, (2) at least one element B selected from the group
consisting of cobalt, zinc, calcium, magnesium, and copper, (3) at
least one element D selected from the group consisting of titanium,
manganese, tin and germanium, (4) no nickel, with (ii) a second
mixed metal oxide comprising (1) at least one element A selected
from the group consisting of lithium and sodium, (2) at least one
element C selected from the group consisting of chromium, boron,
iron, manganese and aluminum, and, (3) at least one element D
selected from the group consisting of titanium, manganese, tin and
germanium, and (4) no nickel, to form a mixture, and (b) heating
the mixture at a temperature of 800-1700.degree. C. for a time of 1
to 1000 minutes to form at least one of particles and agglomerates
of a green pigment.
[0025] An embodiment of the invention is a method of imparting a
green color to a substrate, comprising, (a) applying to a substrate
and (b) firing a nickel-free green pigment comprising a solid
solution of first and second mixed metal oxides, (i) the first
mixed metal oxide comprising (1) at least one element A selected
from the group consisting of lithium and sodium, (2) at least one
element B selected from the group consisting of cobalt, zinc,
calcium, magnesium, and copper, (3) at least one element D selected
from the group consisting of titanium, manganese, tin and
germanium, and (4) no nickel, (ii) the second mixed metal oxide
comprising (1) at least one element A selected from the group
consisting of lithium and sodium, (2) at least one element C
selected from the group consisting of chromium, boron, iron,
manganese and aluminum and, (3) at least one element D selected
from the group consisting of titanium, manganese, tin and
germanium, and (4) no nickel.
[0026] An embodiment of the invention is a method of imparting a
green color to a plastic composition, comprising, melt mixing (a) a
plastic composition, with (b) a nickel-free green pigment
comprising a solid solution of first and second mixed metal oxides,
(i) the first mixed metal oxide comprising (1) at least one element
A selected from the group consisting of lithium and sodium, (2) at
least one element B selected from the group consisting of cobalt,
zinc, calcium, magnesium, and copper, (3) at least one element D
selected from the group consisting of titanium, manganese, tin and
germanium, and (4) no nickel, (ii) the second mixed metal oxide
comprising (1) at least one element A selected from the group
consisting of lithium and sodium, (2) at least one element C
selected from the group consisting of chromium, boron, iron,
manganese and aluminum, (3) at least one element D selected from
the group consisting of titanium, manganese, tin and germanium, and
(4) no nickel.
[0027] The subject pigment compositions are a solid solution of a
[124] spinel and a [134] spinel. In one embodiment, the [124]
spinel has the formula BA(D.sub.3A)O.sub.8. In one embodiment, the
[134] spinel has the formula A.sub.2(C.sub.2D.sub.2)O.sub.8. In one
embodiment, the [124] spinel has the formula BA(D.sub.3A)O.sub.8
and the [134] spinel has the formula
A.sub.2(C.sub.2D.sub.2)O.sub.8. In one embodiment the [124] spinel
has a formula selected from the group consisting of (Co, Zn, Ca,
Mg, Cu)(Li, Na)[(Ti, Mn, Sn, Ge).sub.3(Li, Na)]O.sub.8,
CoLi(Ti.sub.3Li)O.sub.8 and
Co.sub.(1-x)Zn.sub.xLi(Ti.sub.3Li)O.sub.8, where x is 0 to 1. In
one embodiment, the [134] spinel has the formula (Li, Na) [(Cr, B,
Fe, Mn, Al).sub.2(Ti, Mn, Sn, Ge).sub.2]O.sub.8. In one embodiment
the [124] spinel has a formula selected from the group consisting
of (Co, Zn, Ca, Mg, Cu)(Li, Na)[(Ti, Mn, Sn, Ge).sub.3(Li,
Na)]O.sub.8, CoLi(Ti.sub.3Li)O.sub.8 and
Co.sub.(1-x)Zn.sub.xLi(Ti.sub.3Li)O.sub.8, where x is 0 to 1 and
the [134] spinel has the formula (Li, Na) [(Cr, B, Fe, Mn,
Al).sub.2(Ti, Mn, Sn, Ge).sub.2]O.sub.8.
[0028] In a preferred embodiment, the [134] spinel has the formula
Li.sub.2(Cr.sub.2Ti.sub.2)O.sub.8.
[0029] In any embodiment of the invention, the pigment may include
a first mixed metal oxide selected from the group consisting of
CoLi(Ti.sub.3Li) O.sub.8, CoLi(Ti.sub.3Na)O.sub.8,
CoLi(Mn.sub.3Li)O.sub.8, CoLi(Ti.sub.3Li)O.sub.8,
CoLi(Ge.sub.3Li)O.sub.8, CoLi(Mn.sub.3Na)O.sub.8,
CoLi(Ti.sub.3Na)O.sub.8, CoLi(Ge.sub.3Na)O.sub.8,
CoLi(Sn.sub.3Li)O.sub.8, CoLi(Sn.sub.3Na)O.sub.8,
CoNa(Ti.sub.3Li)O.sub.8, CoNa(Ti.sub.3Na)O.sub.8,
CoNa(Mn.sub.3Li)O.sub.8, CoNa(Ti.sub.3Li)O.sub.8,
CoNa(Ge.sub.3Li)O.sub.8, CoNa(Mn.sub.3Na)O.sub.8,
CoNa(Ti.sub.3Na)O.sub.8, CoNa(Ge.sub.3Na)O.sub.8,
CoNa(Sn.sub.3Li)O.sub.8, CoNa(Sn.sub.3Na)O.sub.8,
ZnLi(Ti.sub.3Li)O.sub.8, ZnLi(Ti.sub.3Na)O.sub.8,
ZnLi(Mn.sub.3Li)O.sub.8, ZnLi(Ti.sub.3Li)O.sub.8,
ZnLi(Ge.sub.3Li)O.sub.8, ZnLi(Mn.sub.3Na)O.sub.8,
ZnLi(Ti.sub.3Na)O.sub.8, ZnLi(Ge.sub.3Na)O.sub.8,
ZnLi(Sn.sub.3Li)O.sub.8, ZnLi(Sn.sub.3Na)O.sub.8,
ZnNa(Ti.sub.3Li)O.sub.8, ZnNa(Ti.sub.3Na)O.sub.8,
ZnNa(Mn.sub.3Li)O.sub.8, ZnNa(Ti.sub.3Li)O.sub.8,
ZnNa(Ge.sub.3Li)O.sub.8, ZnNa(Mn.sub.3Na)O.sub.8,
ZnNa(Ti.sub.3Na)O.sub.8, ZnNa(Ge.sub.3Na)O.sub.8,
ZnNa(Sn.sub.3Li)O.sub.8, ZnNa(Sn.sub.3Na)O.sub.8,
CaLi(Ti.sub.3Li)O.sub.8, CaLi(Ti.sub.3Na)O.sub.8,
CaLi(Mn.sub.3Li)O.sub.8, CaLi(Ti.sub.3Li)O.sub.8,
CaLi(Ge.sub.3Li)O.sub.8, CaLi(Mn.sub.3Na)O.sub.8,
CaLi(Ti.sub.3Na)O.sub.8, CaLi(Ge.sub.3Na)O.sub.8,
CaLi(Sn.sub.3Li)O.sub.8, CaLi(Sn.sub.3Na)O.sub.8,
CaNa(Ti.sub.3Li)O.sub.8, CaNa(Ti.sub.3Na)O.sub.8,
CaNa(Mn.sub.3Li)O.sub.8, CaNa(Ti.sub.3Li)O.sub.8,
CaNa(Ge.sub.3Li)O.sub.8, CaNa(Mn.sub.3Na)O.sub.8,
CaNa(Ti.sub.3Na)O.sub.8, CaNa(Ge.sub.3Na)O.sub.8,
CaNa(Sn.sub.3Li)O.sub.8, CaNa(Sn.sub.3Na)O.sub.8,
MgLi(Ti.sub.3Li)O.sub.8, MgLi(Ti.sub.3Na)O.sub.8,
MgLi(Mn.sub.3Li)O.sub.8, MgLi(Ti.sub.3Li)O.sub.8,
MgLi(Ge.sub.3Li)O.sub.8, MgLi(Mn.sub.3Na)O.sub.8,
MgLi(Ti.sub.3Na)O.sub.8, MgLi(Ge.sub.3Na)O.sub.8,
MgLi(Sn.sub.3Li)O.sub.8, MgLi(Sn.sub.3Na)O.sub.8,
MgNa(Ti.sub.3Li)O.sub.8, MgNa(Ti.sub.3Na)O.sub.8,
MgNa(Mn.sub.3Li)O.sub.8, MgNa(Ti.sub.3Li)O.sub.8,
MgNa(Ge.sub.3Li)O.sub.8, MgNa(Mn.sub.3Na)O.sub.8,
MgNa(Ti.sub.3Na)O.sub.8, MgNa(Ge.sub.3Na)O.sub.8,
MgNa(Sn.sub.3Li)O.sub.8, MgNa(Sn.sub.3Na)O.sub.8,
CuLi(Ti.sub.3Li)O.sub.8, CuLi(Ti.sub.3Na)O.sub.8,
CuLi(Mn.sub.3Li)O.sub.8, CuLi(Ti.sub.3Li)O.sub.8,
CuLi(Ge.sub.3Li)O.sub.8, CuLi(Mn.sub.3Na)O.sub.8,
CuLi(Ti.sub.3Na)O.sub.8, CuLi(Ge.sub.3Na)O.sub.8,
CuLi(Sn.sub.3Li)O.sub.8, CuLi(Sn.sub.3Na)O.sub.8,
CuNa(Ti.sub.3Li)O.sub.8, CuNa(Ti.sub.3Na)O.sub.8,
CuNa(Mn.sub.3Li)O.sub.8, CuNa(Ti.sub.3Li)O.sub.8,
CuNa(Ge.sub.3Li)O.sub.8, CuNa(Mn.sub.3Na)O.sub.8,
CuNa(Ti.sub.3Na)O.sub.8, CuNa(Ge.sub.3Na)O.sub.8,
CuNa(Sn.sub.3Li)O.sub.8, CuNa(Sn.sub.3Na)O.sub.8 and combinations
thereof.
[0030] In any embodiment of the invention, the pigment may include
a second mixed metal oxide selected from the group consisting of
Li.sub.2(Cr.sub.2Ti.sub.2)O.sub.8,
Li.sub.2(Cr.sub.2Mn.sub.2)O.sub.8,
Li.sub.2(Cr.sub.2Sn.sub.2)O.sub.8,
Li.sub.2(Cr.sub.2Ge.sub.2)O.sub.8,
Li.sub.2(B.sub.2Ti.sub.2)O.sub.8, Li.sub.2(B.sub.2Mn.sub.2)O.sub.8,
Li.sub.2(B.sub.2Sn.sub.2)O.sub.8, Li.sub.2(B.sub.2Ge.sub.2)O.sub.8,
Li.sub.2(Fe.sub.2Ti.sub.2)O.sub.8,
Li.sub.2(Fe.sub.2Mn.sub.2)O.sub.8,
Li.sub.2(Fe.sub.2Sn.sub.2)O.sub.8,
Li.sub.2(Fe.sub.2Ge.sub.2)O.sub.8,
Li.sub.2(Mn.sub.2Ti.sub.2)O.sub.8,
Li.sub.2(Mn.sub.2Sn.sub.2)O.sub.8,
Li.sub.2(Mn.sub.2Ge.sub.2)O.sub.8,
Li.sub.2(Al.sub.2Ti.sub.2)O.sub.8,
Li.sub.2(Al.sub.2Mn.sub.2)O.sub.8,
Li.sub.2(Al.sub.2Sn.sub.2)O.sub.8,
Li.sub.2(Al.sub.2Ge.sub.2)O.sub.8,
Na.sub.2(Cr.sub.2Ti.sub.2)O.sub.8,
Na.sub.2(Cr.sub.2Mn.sub.2)O.sub.8,
Na.sub.2(Cr.sub.2Ge.sub.2)O.sub.8,
Na.sub.2(Cr.sub.2Sn.sub.2)O.sub.8,
Na.sub.2(B.sub.2Ti.sub.2)O.sub.8, Na.sub.2(B.sub.2Mn.sub.2)O.sub.8,
Na.sub.2(B.sub.2Ge.sub.2)O.sub.8, Na.sub.2(B.sub.2Sn.sub.2)O.sub.8,
Na.sub.2(Fe.sub.2Ti.sub.2)O.sub.8,
Na.sub.2(Fe.sub.2Mn.sub.2)O.sub.8,
Na.sub.2(Fe.sub.2Ge.sub.2)O.sub.8,
Na.sub.2(Sn.sub.2Mn.sub.2)O.sub.8,
Na.sub.2(Mn.sub.2Ti.sub.2)O.sub.8,
Na.sub.2(Mn.sub.2Ge.sub.2)O.sub.8,
Na.sub.2(Al.sub.2Ti.sub.2)O.sub.8,
Na.sub.2(Al.sub.2Mn.sub.2)O.sub.8,
Na.sub.2(Al.sub.2Sn.sub.2)O.sub.8, and
Na.sub.2(Al.sub.2Ge.sub.2)O.sub.8 and combinations thereof.
[0031] The [124] and [134] spinels in the preceding two paragraphs
may be combined in various molar ratios, for example 100:1 to
1:100, 50:1 to 1:50, 25:1 to 1:25, or 10:1 to 1:10 or values in
between. The ratios may be calculated based on element A as set
forth in the formulae BA(D.sub.3A)O.sub.8 or
A.sub.2(C.sub.2D.sub.2)O.sub.8.
[0032] While the pigments of the invention do not include any
intentionally added nickel, it is possible that residual nickel
could be found in product pigments of the invention. Such nickel
may occur naturally in combination with other transition metals
used in the inventive pigments such as cobalt, manganese, iron,
zinc and the like. In any case, regardless of the source, in one
embodiment, the pigments of the invention have leachable nickel of
less than 100 ppm, preferably less than 10 ppm, more preferably
less than 1 ppm when measured in accordance with DIN
EN71/3:2013.
[0033] Pigment Processing.
[0034] The final mixed spinels are formed by combining and
calcining appropriate ratios of reactive compounds, usually salts,
that contain the metals of interest. For example, carbonates,
nitrates, oxalates, phosphates, hydroxides, fluorides, borates,
boric acid, organometallics (such as alkoxides, ethoxides,
methoxides, propoxides, butoxides, pentoxides, etc.), which include
one or more of the metals (or metalloids) of concern, namely Co,
Zn, Ca, Mg, Cu, Li, Na, Ti, Mn, Sn, Ge, Cr, B, Fe, Mn, and Al. The
preceding sentence is intended to be read as disclosing every
possible combination of named metal with every possible anion
listed. The mixtures are calcined at 700-1700.degree. C.,
preferably 700-1500.degree. C., more preferably 800-1100.degree.
C., for 1-10000 minutes, preferably 1-1000 minutes more preferably
1-100 minutes, and milled to a desired particle size, for example
0.001-50 microns, 0.01-40 microns, 0.1-25 microns, or 1-10 microns.
Most preferably, the calcining is done at 800-1100.degree. C. for
60-360 minutes.
[0035] In the methods of the invention, the calcined pigment may be
cooled, for example to room temperature at a rate of 1-50.degree.
C. per minute. The calcined pigment particles may be reduced in
size by, for example, milling, to a D.sub.50 particle size of 1-10
microns.
[0036] The starting particles of salts, (carbonates, nitrates,
oxalates, etc.) may be of any size, but to improve reactivity and
reduce processing times and costs, preferably have a D.sub.90
particle size of less than 20 microns, more preferably less than 10
microns, still more preferably less than 6 microns, and even more
preferably less than 5 microns.
[0037] IN certain embodiments, one or more mineralizers can be
added in the amount of 0.01-10, preferably 0.01-5 wt % of the raw
mixture to help forming the desired spinel, for example, NaCl, LiF,
Na.sub.2SiF.sub.6, Na.sub.3(AlF.sub.6), KCl, NH.sub.4Cl, BaF.sub.2,
CaF.sub.2, H.sub.3BO.sub.3, and others.
[0038] Applications. The pigments of the invention may be used to
impart color to paints (and other coatings), curable coatings (such
as radiation curable), inks, plastics, rubbers, ceramics, enamels,
and glasses. Plastic or rubber substrate compositions that can be
colored and marked using the green pigments according to this
invention can be based upon polymeric materials that can be natural
or synthetic. Halogenated polymers can be used. Examples include
natural resins, rubber, chlororubber, casein, oil-modified alkyd
resins, viscose, cellulose acetate, cellulose propionate, cellulose
acetobutyrate, nitrocellulose, or other cellulose ethers or esters.
Synthetic organic polymers produced by polymerization,
polyaddition, or polycondensation in thermosetting or
thermoplastics can also be colored by this invention. Examples are
polyethylene, polystyrene, polypropylene, polyisobutylene,
polyvinylchloride, polyvinylacetate, polyacrylonitrile, poly
acrylic acid, other polyolefins and substituted polyolefins, as
well as methyacrylic acid esters, butadiene, as well as co polymers
of the above mentioned. Examples from polyaddition and
polycondensation resins are the condensation products of
formaldehyde with phenols, phenolic resins, urea, thiourea, and
melamine, amino resins, polyesters, polyamides, polycarbonates,
and/or silicones. These polymers can be present individually or as
mixtures as plastic material or melts spun into fibers. They can
also be dissolved as film formers or binders for laquers, paints,
or printing inks such as linseed oil, nitrocellulose, melamine
resins, acrylic resins, urea formaldehyde resins and the like. The
pigmentary use of the present green pigments and compounds in other
coatings or materials such as carbon-carbon composites may also
provide advantages with regard to IR reflection. Also a plastic
body as a substrate which would contain the pigment (such as vinyl
siding) and/or any substrate (glass, ceramic, metal, plastic,
composite) having thereon an organic coating or paint which would
contain and utilize the high contrast laser markability, electronic
properties, or low heat build-up properties of the green containing
pigments of the invention.
[0039] Curable coatings. Representative useful thermoplastic
polymers include polyolefins such as polyethylene and
polypropylene, polyesters, polycarbonates, polysulfones,
polyimides, polyamides, polyurethanes, acrylics, styrene acrylics,
polyvinyl chlorides, and others. For certain high solid
applications, thermoplastic polymers having a number average
molecular weight less than 35,000, and optionally less than about
20,000, and optionally less than 10,000, will provide relatively
low viscosity solutions when dissolved in suitable amounts of the
unsaturated monomers, oligomers and reactants. Thermoplastic
acrylic polymers are generally useful to provide favorable cost and
performance characteristics, and are conveniently prepared by
methods well known in the art such as by solution polymerization of
acrylic and/or methacrylic monomers in an appropriate solvent or
diluent.
[0040] An embodiment of the invention is a paint or coating
comprising particles made by any method disclosed herein, wherein
the paint or coating exhibits a total solar reflectance over black
of at least 15% and preferably at least 20%, in accordance with
ASTM E903, which is calculated based on standard reference spectral
irradiance ASTM G173.
[0041] An embodiment of the invention is a paint or coating
comprising nickel-free pigments disclosed elsewhere herein wherein
the paint or coating exhibits a total solar reflectance over black
of at least 15% and preferably at least 20%, in accordance with
ASTM E903, which is calculated based on standard reference spectral
irradiance ASTM G173.
[0042] An embodiment of the invention is a plastic composition
comprising particles made by any method disclosed herein, wherein
the plastic composition exhibits a total solar reflectance over
black of at least 15% and preferably at least 20%, in accordance
with ASTM E903, which is calculated based on standard reference
spectral irradiance ASTM G173.
[0043] An embodiment of the invention is a plastic composition
comprising nickel-free pigments disclosed elsewhere herein wherein
the plastic composition exhibits a total solar reflectance over
black of at least 15% and preferably at least 20%, in accordance
with ASTM E903, which is calculated based on standard reference
spectral irradiance ASTM G173.
[0044] When used in a plastic composition or curable coating, the
green pigments of the invention may be used together with other
pigments. Any mixed metal oxide pigment may be used in conjunction
with the green pigments of the invention. Preferably, such
additional pigments are also nickel-free in accordance with the
goals of the invention. However, in some embodiments,
nickel-containing pigments may be used. Pigments such as Pigment
Yellow 184, Pigment Yellow 227, Pigment Orange 82 and Pigment
Yellow 216 may be used in any combination with the green pigments
of the invention. Also, singly or in combination, BiV, SnTiZn and
NiTiO3 may be used.
[0045] An embodiment of the invention is a plastic, rubber or
curable coating as set forth in the preceding two paragraphs
including a green pigment particle disclosed elsewhere herein or
made by any method disclosed elsewhere herein.
EXAMPLES
[0046] The following examples illustrate, but do not limit, the
scope of the invention.
Example 1
[0047] The compound
Li.sub.1.5Co.sub.0.5(Ti.sub.2.5Li.sub.0.5Cr)O.sub.8 is produced by
dry mixing of the metal oxides or carbonates (Table 1, below)
followed by calcining at 900.degree. C. for 8 hours in open saggers
and wet milling to D.sub.90 of 4.5 microns.
TABLE-US-00001 TABLE 1 Recipe to produce
Li.sub.1.5Co.sub.0.5(Ti.sub.2.5Li.sub.0.5Cr)O.sub.8 19.09 kg
lithium carbonate 9.68 kg cobalt oxide 51.59 kg titanium dioxide
19.64 kg chromium oxide
[0048] The production of
Li.sub.1.5Co.sub.0.5(Ti.sub.2.5Li.sub.0.5Cr).sub.8 can be
exemplified by the following reaction:
Li.sub.2(Cr.sub.2Ti.sub.2)O.sub.8+CoLi(Ti.sub.3Li)O.sub.8->Li.sub.3Co-
(Ti.sub.5LiCr.sub.2)O.sub.16.dbd.Li.sub.1.5Co.sub.0.5(Ti.sub.2.5Li.sub.0.5-
Cr)O.sub.8.
[0049] The pigment
(Li.sub.1.5Co.sub.0.5(Ti.sub.2.5Li.sub.0.5Cr)O.sub.8) produces the
following coloristic properties (CIELab D65 10.degree.), where the
Masstone sample includes 6.4 g Plastisol and 0.3 g Pigment, while
the Tint sample includes 6.4 grams Plastisol; 0.3 grams Pigment and
0.1.2 grams TiO.sub.2-- Color values (CIELab D65 100) of that trial
measured in Plastisol:
TABLE-US-00002 Masstone Tint L* 45.9 74.4 a* -26 -18.2 b* 14.4 10.2
Hue 151.1.degree. 150.9.degree. Angle
[0050] The plastisol in this and all examples is a suspension of
PVC in a liquid plasticizer, which is a standard formulation
commercially available from: Rottolin-Werk--Julius Rotter & Co.
KG, Bayreuth, Germany; and has the product name: Plastisol Typ
U91.7.0.429.59.
[0051] In addition, the TSR (over Black) of this compound is 31 as
compared to a conventional Ni containing Pigment, which exhibits a
TSR of 22 when identically formulated. TSR is measured in
accordance with ASTM E903, which is calculated based on standard
reference spectral irradiance ASTM G173.
Example 2
Li.sub.4Co.sub.3(Ti.sub.11Li.sub.3Cr.sub.2)O.sub.32
[0052] The following oxides and carbonates are dry mixed, followed
by calcining at 900.degree. C. for 8 hours in open saggers,
followed by wet milling to d90 of 4.3 microns.
[0053] Recipe:
TABLE-US-00003 19.06 kg lithium carbonate 14.49 kg cobalt oxide
56.65 kg titanium dioxide 9.8 kg chromium oxide
[0054] Color values (CIELab D65 10.degree.) of that trial measured
in Plastisol:
TABLE-US-00004 Masstone Tint L* 45.9 74.8 a* -31.5 -22 b* 7.2
4.4
Example 3
(Co.sub.1.3Zn.sub.0.2Li.sub.2)(Ti.sub.5.5Li.sub.1.5Cr)O.sub.8
[0055] The following oxides and carbonates are dry mixed, followed
by calcining at 900.degree. C. for 8 hours in open saggers,
followed by wet milling to d90 of 4.4 microns.
[0056] Recipe:
TABLE-US-00005 8.53 kg lithium carbonate 6.42 Kg cobalt oxide 27.97
kg titanium dioxide 5.01 kg chromium oxide 1.07 Kg Zinc oxide
[0057] Color values (CIELab D65 10.degree.) of that trial measured
in Plastisol:
TABLE-US-00006 Masstone Tint L* 49 75.6 a* -31.3 -21.4 b* 8.5
5.0
Example 4
(CoLi.sub.0.5)(Ti.sub.2Cr.sub.0.5Sb.sub.0.5Li)O.sub.8
[0058] The following oxides and carbonates are dry mixed, followed
by calcining at 900.degree. C. for 8 hours in open saggers,
followed by wet milling to d90 of 4.4 microns.
[0059] Recipe:
TABLE-US-00007 8.45 kg lithium carbonate 11.42 kg cobalt oxide
24.34 kg titanium dioxide 5.79 kg chromium oxide 10.34 kg antimony
oxide
[0060] Color values (CIELab D65 10.degree.) of that trial measured
in Plastisol:
TABLE-US-00008 Masstone Tint L* 41.3 72.4 a* -20.9 -16 b* 8.5
5.8
Example 5
LiCo.sub.0.5(Ti.sub.2.5LiCr)O.sub.8, with Mineralizer
[0061] The following oxides and carbonates are dry mixed, followed
by calcining at 900.degree. C. for 8 hours in open saggers,
followed by wet milling to d90 of 5.3 microns.
[0062] Recipe:
TABLE-US-00009 37.80 kg lithium carbonate 19.16 kg cobalt oxide
103.18 kg titanium dioxide 38.89 kg chromium oxide 2 kg Ammonium
chloride
[0063] Color values (CIELab D65 10.degree.) of that trial measured
in Plastisol:
TABLE-US-00010 Masstone Tint L* 46.2 74.3 a* -27.2 -19.2 b* 15.0
10.3
Test of Example 1 & 2 Pigments on a Flat Glass Enamel
[0064] Pigments from Examples 1 & 2 were tested with 15%
pigment and 85% glass flux 104007, lead-free, commercially
available from Ferro corporation, Cleveland, Ohio. The
pigment/glass mixture was screen printing on 4 mm float glass and
fired at 690.degree. C. for 3 min.
[0065] The resultant color values (CIELab D65 10.degree.) were:
TABLE-US-00011 Example 1 Example 2 L* 48.7 46.5 a* -29.1 -31.7 b*
17.7 13.5
[0066] In the spectrum in FIG. 1, the upper curve represents the
inventive pigment
Li.sub.1.5Co.sub.0.5(Ti.sub.2.5Li.sub.0.5Cr)O.sub.8. The lower
curve represents Ferro's conventional Nickel-containing green
pigment (BO03433). The vertical dashed lines represent the bounds
of the visible spectrum. The inventive nickel-free pigment provides
increased reflectance over the conventional nickel-containing green
pigment over virtually the entire EM spectrum from 250 to 2500
nanometers, especially in the overall infrared region and
especially the near infrared region.
[0067] The subject pigment compositions can exhibit improved solar
reflectance properties such that the pigment compositions reflect a
relatively high proportion of light having a wavelength between 780
and 2500 nm (i.e., the infrared spectrum), while reflecting a
relatively low proportion of light having a wavelength between 380
and 780 nm (i.e., the visible spectrum), which shows either
light-tone or dark-tone colors. These unique reflection
characteristics enable the preferred pigment compositions to
selectively reflect infrared (IR) radiation while not significantly
reflecting light within the visible spectrum.
[0068] Hence, the inventive pigments exhibit significant
reflectance in the near infrared range and relatively low (under
25%) in the visible range. Naturally, as a green pigment, the
inventive pigment exhibits a reflectance peak in the 500-550 nm
range.
[0069] Thus, the pigment compositions maintain their desired
appearance and color, e.g., green, while also reflecting
significant amounts of IR radiation.
[0070] The foregoing and other features of the invention are
hereinafter more fully described and particularly pointed out in
the claims, the following description setting forth in detail
certain illustrative embodiments of the invention, these being
indicative, however, of but a few of the various ways in which the
principles of the invention may be employed.
* * * * *