Green pigment

Abstract

An inorganic green pigment includes a material with spinel structure of the general formula selected from the following formulas a) (A.sub.1xB.sub.1+x)(C.sub.3xyD.sub.2xB.sub.1x2yNi.sub.3y)O.sub.8, wherein 0.05x0.9 and 0.05y0.5, and wherein x+2y1; b) (A.sub.1xB.sub.1+x)(C.sub.3xyD.sub.2xyB.sub.1xyNi.sub.2y)O.sub.8, wherein 0.05x0.5 and 0.05y0.5; c) (A.sub.1xB.sub.1+x)(C.sub.3x4yD.sub.2xB.sub.1x+yNb.sub.y)O.sub.8, wherein 0.05x0.5 and 0.05y0.2; d) (A.sub.1xB.sub.1+x)(C.sub.3xD.sub.2x2yB.sub.1x+yNb.sub.y)O.sub.8, wherein 0.05x0.9 and 0.05y0.2, and wherein xy; and e) (A.sub.1xB.sub.1+x)(C.sub.3x3yD.sub.2xB.sub.1xNb.sub.2yNi.sub.y)O.sub.8, wherein 0.05x0.9 and 0.05y0.2, wherein A is at least one element selected from Co, Zn, Ca, Mg and Cu, wherein B is at least one element selected from Li and Na, wherein C is at least one element selected from Ti, Mn, Sn and Ge, and wherein D is at least one element selected from Cr, B, Fe, Mn and Al.

Claims

1. A green pigment, comprising a material with spinel structure of a formula selected from the following formulas: a) (A.sub.1xB.sub.1+x)(C.sub.3xyD.sub.2xB.sub.1x2yNi.sub.3y)O.sub.8, wherein 0.05x0.9 and 0.05y0.5, and wherein x+2y1; b) (A.sub.1xB.sub.1+x)(C.sub.3xyD.sub.2xyB.sub.1xyNi.sub.2y)O.sub.8, wherein 0.05x0.5 and 0.05y0.5; c) (A.sub.1xB.sub.1+x)(C.sub.3x4yD.sub.2xB.sub.1x+yNb.sub.y)O.sub.8, wherein 0.05x0.5 and 0.05y0.2; d) (A.sub.1xB.sub.1+x)(C.sub.3xD.sub.2x2yB.sub.1x+yNb.sub.y)O.sub.8, wherein 0.05x0.9 and 0.05y0.2, and wherein xy; and e) (A.sub.1xB.sub.1+x)(C.sub.3x3yD.sub.2xB.sub.1xNb.sub.2yNi.sub.y)O.sub.8, wherein 0.05x0.9 and 0.05y0.2, wherein in said formulas A is at least one element selected from Co, Zn, Ca, Mg and Cu, B is at least one element selected from Li and Na, C is at least one element selected from Ti, Mn, Sn and Ge, and D is at least one element selected from Cr, B, Fe, Mn and Al.

2. The green pigment of claim 1, wherein the green pigment is a nickel-containing mixed oxide selected from (Co.sub.1xLi.sub.1+x)(Ti.sub.3xyCr.sub.2xLi.sub.1x2yNi.sub.3y)O.sub.8 and (Co.sub.1xLi.sub.1+x)(Ti.sub.3xCr.sub.2xyLi.sub.1xyNi.sub.2y)O.sub.8.

3. The green pigment of claim 1, wherein the green pigment is a niobium-containing mixed oxide selected from (Co.sub.1xLi.sub.1+x)(Ti.sub.3x4yCr.sub.2xLi.sub.1x+yNb.sub.3y)O.sub.8, and (Co.sub.1xLi.sub.1+x)(Ti.sub.3xCr.sub.2x2yLi.sub.1x+yNb.sub.y)O.sub.8.

4. The green pigment of claim 1, wherein the green pigment is a nickel and niobium containing mixed oxide of the formula (Co.sub.1xLi.sub.1+x)(Ti.sub.3x3yCr.sub.2xLi.sub.1xNb.sub.2yNi.sub.y)O.sub.8.

5. The green pigment of claim 1, having a nickel release of less than 80 mg/kg and a Cobalt release of less than 30 mg/kg, according to DIN EN 71.3:2013-05.

6. A method for producing a green pigment, said method comprising the steps of: producing a mixture by mixing carbonates, nitrates, oxalates, phosphates, hydroxides, fluorides, borates, or corresponding metal organic compounds of metals selected from Co, Zn, Ca, Mg, Cu, Li, Na, Ti, Mn, Sn, Ge, Cr, B, Fe, Mn, Al, Ni and Nb; and calcining the mixture at a temperature from 900 C. to 1400 C. for 1 h to 3 h to form a pigment of a formula selected from the following formulas a) (A.sub.1xB.sub.1+x)(C.sub.3xyD.sub.2xB.sub.1x2yNi.sub.3y)O.sub.8, wherein 0.05x0.9 and 0.05y0.5, and wherein x+2y1; b) (A.sub.1xB.sub.1+x)(C.sub.3xyD.sub.2xyB.sub.1xyNi.sub.2y)O.sub.8, wherein 0.05x0.5 and 0.05y0.5; c) (A.sub.1xB.sub.1+x)(C.sub.3x4yD.sub.2xB.sub.1x+yNb.sub.y)O.sub.8, wherein 0.05x0.5 and 0.05y0.2; d) (A.sub.1xB.sub.1+x)(C.sub.3xD.sub.2x2yB.sub.1x+yNb.sub.y)O.sub.8, wherein 0.05x0.9 and 0.05y0.2, and wherein xy; and e) (A.sub.1xB.sub.1+x)(C.sub.3x3yD.sub.2xB.sub.1xNb.sub.2yNi.sub.y)O.sub.8, wherein 0.05x0.9 and 0.05y0.2, wherein in said formulas A is at least one element selected from Co, Zn, Ca, Mg and Cu, B is at least one element selected from Li and Na, C is at least one element selected from Ti, Mn, Sn and Ge, and D is at least one element selected from Cr, B, Fe, Mn and Al.

7. The method of claim 6, further comprising after the calcining step, milling the calcinated mixture in a ball mill.

8. A paint composition, a plastic or a coating containing the green pigment of claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) Other features and advantages of the present invention will be more readily apparent upon reading the following description of currently preferred exemplified embodiments of the invention with reference to the accompanying drawing, in which

(2) FIG. 1 shows an x-ray diffraction diagram of the compound of Example 1;

(3) FIG. 2 shows an x-ray diffraction diagram of the compound of Example 2;

(4) FIG. 3 shows an x-ray diffraction diagram of the compound of Example 3; and

(5) FIG. 4 shows an x-ray diffraction diagram of the compound Li.sub.1.5Co.sub.0.5(Ti.sub.2.5Li.sub.0.5Cr)O.sub.8.

(6) FIG. 5 shows a reflection spectrum of the pigment according to the invention and a reflection spectrum of a known green pigment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(7) Throughout all the Figures, same or corresponding elements may generally be indicated by same reference numerals. These depicted embodiments are to be understood as illustrative of the invention and not as limiting in any way. It should also be understood that the figures are not necessarily to scale and that the embodiments are sometimes illustrated by graphic symbols, phantom lines, diagrammatic representations and fragmentary views. In certain instances, details which are not necessary for an understanding of the present invention or which render other details difficult to perceive may have been omitted.

(8) The method according to the invention is explained in more detail by way of exemplary embodiments.

Example 1

(Li.SUB.1.5.Co.SUB.0.5.)(Ti.SUB.2.4.Li.SUB.0.525.CrNb.SUB.0.075.)O.SUB.8

(9) FIG. 1 shows an x-ray diffraction diagram of the compound of Example 1. The x-ray diffraction diagram shows that the spinel is generated free of phase shift with integrated niobium.

(10) The composition (Li.sub.1.5Co.sub.0.5)(Ti.sub.2.4Li.sub.0.525CrNb.sub.0.075)O.sub.8 was produced by dry-mixing the metal oxides and/or carbonates of Table 1. Subsequently the mixture was annealed at a temperature of 960 C. for 2 h and the product was then milled in a ball mill.

(11) TABLE-US-00001 TABLE 1 kg Lithium Carbonate 19.02 Cobalt Oxide 9.53 Titanium Oxide 48.74 Chromium Oxide 19.33 Niobium Oxide 3.38 Nickel Oxide / 100

(12) The pigment (Li.sub.1.5Co.sub.0.5)(Ti.sub.2.4Li.sub.0.525CrNb.sub.0.075)O.sub.8 has the following color properties:

(13) Volton (10% pigment in plastisol) (CIELab D65 10):

(14) TABLE-US-00002 L* 47.4 a* 31.3 b* 15.4

(15) Dilution (2% pigment and 10% Titanium oxide in plastisol) (CIELab D65 10):

(16) TABLE-US-00003 L* 88.1 a* 17.5 b* 6.9

Example 2

(Li.SUB.11/3.Co.SUB.2/3.)(Ti.SUB.21/3.Cr.SUB.2/3.Ni)O.SUB.8

(17) FIG. 2 shows an x-ray diffraction diagram of the compound of Example 2. The x-ray diffraction diagram shows that in addition to the spinel a small proportion of a rutile phase is generated.

(18) The composition (Li.sub.11/3Co.sub.2/3)(Ti.sub.21/3Cr.sub.2/3Ni)O.sub.8 was produced by dry mixing the metal oxides and/or carbonates of Table 2. Subsequently the mixture was annealed at a temperature of 960 C. for 2 h and the product was then milled in a ball mill.

(19) TABLE-US-00004 TABLE 2 kg Lithium Carbonate 11.83 Cobalt Oxide 13.02 Titanium Oxide 44.78 Chromium Oxide 12.18 Niobium Oxide / Nickel Oxide 18.19 100

(20) The pigment (Li.sub.11/3Co.sub.2/3)(Ti.sub.21/3Cr.sub.2/3Ni)O.sub.8 has the following color properties:

(21) Volton (10% pigment in plastisol) (CIELab D65 10):

(22) TABLE-US-00005 L* 50.4 a* 36.4 b* 16.2

(23) Dilution (2% pigment and 10% Titanium oxide in plastisol) (CIELab D65 10):

(24) TABLE-US-00006 L* 79.7 a* 21.3 b* 9.3

(25) In addition the Nickel release and Cobalt release of the pigment was determined by measuring the solubility over a time period of 2 h in 1 n HCl. Hereby a Nickel release of 71 mg/kg and a Cobalt release of 28 mg/kg could be determined.

Example 3

(Li.SUB.1.5.Co.SUB.0.5.)(Ti.SUB.2.26.Li.SUB.0.525.CrNb.SUB.0.16.Ni.SUB.0.08.)O.SUB.8

(26) FIG. 3 shows an x-ray diffraction diagram of the compound of Example 3. The x-ray diffraction diagram shows that the spinel is generated free from phase shift with integrated Nb and Ni.

(27) The composition (Li.sub.1.5Co.sub.0.5)(Ti.sub.2.26Li.sub.0.525CrNb.sub.0.16Ni.sub.0.08)O.sub.8 was produced by dry mixing the metal oxides and/or carbonates of Table 3. Subsequently the mixture was annealed at a temperature of 1100 C. for 2 h and the product was then milled in a ball mill.

(28) TABLE-US-00007 TABLE 3 kg Lithium Carbonate 18.72 Cobalt Oxide 9.49 Titanium Oxide 45.56 Chromium Oxide 19.25 Niobium Oxide 5.43 Nickel Oxide 1.55 100

(29) The pigment (Li.sub.1.5Co.sub.0.5)(Ti.sub.2.26Li.sub.0.525CrNb.sub.0.16Ni.sub.0.08)O.sub.8 has the following color properties:

(30) Volton (10% pigment in plastisol) (CIELab D65 10):

(31) TABLE-US-00008 L* 49.5 a* 29.9 b* 12.1

(32) Dilution (2% pigment and 10% Titanium oxide in plastisol) (CIELab 065 10):

(33) TABLE-US-00009 L* 80.6 a* 17.6 b* 7.1

(34) FIG. 4 shows an x-ray diffraction diagram of the compound Li.sub.1.5Co.sub.0.5(Ti.sub.2.5Li.sub.0.5Cr)O.sub.8. The x-ray diffraction diagram shows that in addition to the spinel a small proportion of a rutile phase is generated.

(35) FIG. 5 shows a reflection spectrum of the pigment according to the invention (designated Helvetia in FIG. 5) and a reflection spectrum of a known green pigment according to U.S. Pat. No. 9,187,617B1 of the Ferro Corporation (designated Ferro in FIG. 5).