Copper containing infrared reflective pigment compositions
Pigment compositions are described that advantageously increase total solar reflectance. Also described are methods of making pigment compositions. The pigment compositions can contain copper oxide; copper antimony oxides, copper bismuth oxides, or combinations thereof; and alkaline earth metal oxides, early-transition metal oxides, post-transition metal oxides, metalloid (semi-metal) oxides, rare-earth metal oxides, or combinations thereof.
1. A colored pigment composition comprising a mixed metal oxide pigment having a crystal structure that includes two or more types of metal atoms and oxygen atoms, and is of the formula:
CuO.(A) x .(B) y ,
where x=0.01-2; y=0.01-2; A is antimony oxides, bismuth oxides, or combinations thereof; B is oxides of Mg, Ca, Sr, Ba, Ti, Zr, Zn, Al, Si, B, Ce, or combinations thereof wherein the pigment composition exhibits an average reflection of about 20% or less for light having a wavelength between 380 nm and 780 nm, and the pigment composition exhibits an average reflection of about 20% or more for light having a wavelength between 780 nm and 2500 nm and wherein the pigment composition is in a powder form having an average particle size of about 0.2 μm or more and about 15 μm or less.
2. The pigment composition of claim 1 , wherein A is Sb 2 O 3 , Sb 2 O 5 , Bi 2 O 3 , or combinations thereof.
3. The pigment composition of claim 1 , wherein B is MgO, CaO, SrO, TiO 2 , ZrO 2 , ZnO, SiO 2 , B 2 O 3 , CeO 2 , or combinations thereof.
4. The pigment composition of claim 1 , wherein the pigment composition exhibits an average reflection of about 30% or more for light having a wavelength between 1,300 and 1,600 nm.
5. The pigment composition of claim 1 , wherein the oxides of Mg, Ca, Sr, Ba, Ti, Zr, Zn, Al, Si, B, Ce, or combinations thereof contain metal cations comprising a valence shell with only empty (d 0 ), full-filled d-orbitals (d 10 ), or no d-orbital electrons.
6. The pigment composition of claim 1 , wherein the pigment composition exhibits a total solar reflectance of about 15% of more.