초록 ▼

Multilayered magnetic pigment flakes and foils are provided. The pigment flakes can have a stacked layer structure on opposing sides of a magnetic core, or can be formed as an encapsulant structure with encapsulating layers around the magnetic core. The magnetic core in the stacked layer structure

Multilayered magnetic pigment flakes and foils are provided. The pigment flakes can have a stacked layer structure on opposing sides of a magnetic core, or can be formed as an encapsulant structure with encapsulating layers around the magnetic core. The magnetic core in the stacked layer structure includes a magnetic layer that is sandwiched between opposing insulator layers, which in turn are sandwiched between opposing reflector layers. Similarly, the magnetic core in the encapsulant structure includes a magnetic layer that is surrounded by an insulator layer, which in turn is surrounded by a reflector layer. The insulator layers in the pigment flakes substantially prevent corrosion of the flakes when exposed to harsh environments. Some embodiments of the pigment flakes and foils exhibit a discrete color shift at differing angles of incident light or viewing. The pigment flakes can be interspersed into liquid media such as paints or inks to produce colorant compositions for subsequent application to objects or papers. The foils can be laminated to various objects or can be formed on a carrier substrate.

대표청구항 ▼

What is claimed is: 1. A magnetic pigment flake, comprising: a central magnetic layer having a first major surface, an opposing second major surface, and at least one side surface; a first insulator layer over the first major surface of the magnetic layer; a second insulator layer over the second m

What is claimed is: 1. A magnetic pigment flake, comprising: a central magnetic layer having a first major surface, an opposing second major surface, and at least one side surface; a first insulator layer over the first major surface of the magnetic layer; a second insulator layer over the second major surface of the magnetic layer; a first reflector layer over the first insulator layer; and a second reflector layer over the second insulator layer; wherein the insulator layers have an effective thickness for substantially preventing corrosion of the pigment flake. 2. The pigment flake of claim 1, wherein the pigment flake exhibits a reflectivity corresponding to the reflectivity of the reflector layers and exhibits magnetic characteristics based on the relative magnetism of the magnetic layer. 3. The pigment flake of claim 1, wherein the first and second insulator layers are over each of the first and second major surfaces but are not over the at least one side surface of the magnetic layer. 4. The pigment flake of claim 1, wherein the first and second reflector layers form part of a contiguous reflecting layer substantially surrounding the magnetic layer and the insulator layers. 5. The pigment flake of claim 1, wherein the magnetic layer comprises a soft magnetic material. 6. The pigment flake of claim 1, wherein the magnetic layer comprises a material with a coercivity of less than about 2000 Oe. 7. The pigment flake of claim 1, wherein the magnetic layer comprises a material with a coercivity of less than about 300 Oe. 8. The pigment flake of claim 1, wherein the magnetic layer comprises a material selected from the group consisting of iron, nickel, cobalt, gadolinium, terbium, dysprosium, erbium, and alloys or oxides thereof. 9. The pigment flake of claim 1, wherein the magnetic layer comprises a material selected from the group consisting of Fe/Si, Fe/Ni, Fe/Co, Fe/Ni/Mo, and combinations thereof. 10. The pigment flake of claim 1, wherein the magnetic layer comprises a hard magnetic material. 11. The pigment flake of claim 1, wherein the magnetic layer comprises a material selected from the group consisting of SmCo5, NdCo5, Sm2Co17, Nd2Fe14B, TbFe2, and combinations thereof. 12. The pigment flake of claim 1, wherein the magnetic layer comprises a material selected from the group consisting of Fe3 O4, NiFe2O4, MnFe2O4, CoFe2O4, YIG, GdIG, and combinations thereof. 13. The pigment flake of claim 1, wherein the magnetic layer has a physical thickness of about 20 nm to about 3000 nm. 14. The pigment flake of claim 1, wherein the insulator layers comprise a dielectric material. 15. The pigment flake of claim 1, wherein the insulator layers comprise at least one material selected from the group consisting of aluminum oxide, magnesium fluoride, nickel oxide, and combinations thereof. 16. The pigment flake of claim 1, wherein the insulator layers have a physical thickness of at least about 10 nm. 17. The pigment flake of claim 1, wherein the reflector layers comprise a reflective material selected from the group consisting of aluminum, silver, copper, gold, platinum, tin, titanium, palladium, nickel, cobalt, rhodium, niobium, chromium, iridium, and combinations or alloys thereof. 18. The pigment flake of claim 1, wherein the reflector layers have a physical thickness of about 20 nm to about 1000 nm. 19. A magnetic colorant composition, comprising: a pigment medium; and a plurality of pigment flakes dispersed in the pigment medium, the pigment flakes having a multilayer structure substantially the same as the pigment flake defined in claim 1. 20. The colorant composition of claim 19, wherein the pigment medium comprises a material selected from the group consisting of acrylic melamine, urethanes, polyesters, vinyl resins, acrylates, methyl methacrylate, ABS resins, epoxies, styrenes, ink and paint formulations based on alkyd resins, and mixtures thereof. 21. A magnetic pigment flake, comprising: a central magnetic layer; an insulator layer substantially surrounding the magnetic layer; and a reflector layer substantially surrounding the insulator layer; wherein the insulator layer has an effective thickness for substantially preventing corrosion of the pigment flake. 22. The pigment flake of claim 21, wherein the insulator layer comprises a dielectric material. 23. The pigment flake of claim 21, wherein the insulator layer comprises a material selected from the group consisting of aluminum oxide, magnesium fluoride, nickel oxide, and combinations thereof. 24. The pigment flake of claim 21, wherein the insulator layers have a physical thickness of about 20 nm to about 40 nm. 25. A magnetic colorant composition, comprising: a pigment medium; and a plurality of pigment flakes dispersed in the pigment medium, the pigment flakes having a multilayer structure substantially the same as the pigment flake defined in claim 21. 26. A magnetic color shifting pigment flake, comprising: a central magnetic layer having a first major surface and an opposing second major surface; a first insulator layer over the first major surface of the magnetic layer; a second insulator layer over the second major surface of the magnetic layer; a first reflector layer over the first insulator layer; a second reflector layer over the second insulator layer; a first dielectric layer over the first reflector layer, a second dielectric layer over the second reflector layer; a first absorber layer over the first dielectric layer; and a second absorber layer over the second dielectric layer; wherein the pigment flake exhibits a discrete color shift such that the pigment flake has a first color at a first angle of incident light or viewing and a second color different from the first color at a second angle of incident light or viewing, and the insulator layers have an effective thickness for substantially preventing corrosion of the pigment flake. 27. The pigment flake of claim 26, wherein the insulator layers comprise a dielectric material. 28. The pigment flake of claim 26, wherein the insulator layers comprise at least one material selected from the group consisting of aluminum oxide, magnesium fluoride, nickel oxide, and combinations thereof. 29. The pigment flake of claim 26, wherein the insulator layers have a physical thickness of about 20 nm to about 40 nm. 30. The pigment flake of claim 26, wherein the first and second dielectric layers comprise a dielectric material having an index of retraction of about 1.65 or less. 31. The pigment flake of claim 30, wherein the dielectric material is selected from the group consisting of silicon dioxide, aluminum oxide, magnesium fluoride, aluminum fluoride, cerium fluoride, lanthanum fluoride, neodymium fluoride, samarium fluoride, barium fluoride, calcium fluoride, lithium fluoride, and combinations thereof. 32. The pigment flake of claim 26, wherein the first and second dielectric layers comprise a dielectric material having an index of refraction of greater than about 1.65. 33. The pigment flake of claim 32, wherein the dielectric material is selected from the group consisting of zinc sulfide, zinc oxide, zirconium oxide, titanium dioxide, diamond-like carbon, indium oxide, indium-tin-oxide, tantalum pentoxide, cerium oxide, yttrium oxide, europium oxide, iron oxides, hafnium nitride, hafnium carbide, hafnium oxide, lanthanum oxide, magnesium oxide, neodymium oxide, praseodymium oxide, samarium oxide, antimony trioxide, silicon monoxide, selenium trioxide, tin oxide, tungsten trioxide, and combinations thereof. 34. The pigment flake of claim 26, wherein the first and second dielectric layers have substantially the same optical thickness. 35. The pigment flake of claim 26, wherein the first and second dielectric layers are composed of the same material. 36. The pigment flake of claim 26, wherein the first and second dielectric layers comprise a dielectric optical stack having a plurality of alternating layers of a high index material and a low index material. 37. The pigment flake of claim 26, wherein the first and second absorber layers comprise a material that is uniformly absorbing in the visible part of the electromagnetic Spectrum. 38. The pigment flake of claim 26, wherein the first and second absorber layers comprise a material that is non-uniformly absorbing in the visible part of the electromagnetic spectrum. 39. The pigment flake of claim 26, wherein the first and second absorber layers comprise an absorbing material selected from the group consisting of chromium, nickel, aluminum, silver, copper, palladium, platinum, titanium, vanadium, cobalt, iron, tin, tungsten, molybdenum, rhodium, niobium, carbon, graphite, silicon, germanium, and compounds, mixtures, or alloys thereof. 40. The pigment flake of claim 26, wherein the first and second absorber layers comprise an absorbing material selected from the group consisting of metal oxides, metal sulfides, metal carbides, and combinations thereof. 41. The pigment flake of claim 26, wherein the first and second absorber layers have a physical thickness of about 3 nm to about 50 nm. 42. The pigment flake of claim 26, wherein the first and second absorber layers have substantially the same physical thickness. 43. The pigment flake of claim 26, wherein the first and second absorber layers are composed of the same material. 44. The pigment flake of claim 26, wherein the first and second reflector layers form part of a contiguous reflecting layer substantially surrounding the magnetic layer and the insulator layers, the first and second dielectric layers form part of a contiguous dielectric layer substantially surrounding the contiguous reflecting layer, and first and second absorber layers form part of a contiguous absorbing layer substantially surrounding the contiguous dielectric layer. 45. The pigment flake of claim 44, further comprising a transparent overlayer coating surrounding the absorbing layer. 46. The pigment flake of claim 26, wherein the first and second dielectric layers form part of a contiguous dielectric layer substantially surrounding the reflector layers, the insulator layers, and the magnetic layer, and first and second absorber layers form part of a contiguous absorbing layer substantially surrounding the contiguous dielectric layer. 47. The pigment flake of claim 46, further comprising a transparent overlayer coating surrounding the absorbing layer. 48. The pigment flake of claim 26, wherein the first and second absorber layers form part of a contiguous absorbing layer substantially surrounding the dielectric layers, the reflector layers, the insulator layers, and the magnetic layer. 49. The pigment flake of claim 48, further comprising a transparent overlayer coating surrounding the absorbing layer. 50. The pigment flake of claim 26, further comprising a first transparent overlayer coating over the first absorber layer, and a second transparent overlayer coating over the second absorber layer. 51. A magnetic color shifting pigment composition comprising a plurality of color shifting pigment flakes, the pigment flakes having a multilayer structure substantially the seine as the pigment flake defined in claim 26. 52. A magnetic color-shifting colorant composition, comprising: a pigment medium; and a plurality of color-shifting pigment flakes dispersed in the pigment medium, the pigment flakes having a multilayer structure substantially the same as the pigment flake defined in claim 26. 53. A color shifting magnetic pigment flake, comprising: a central magnetic layer; an insulator layer substantially surrounding the magnetic layer; a reflector layer substantially surrounding the insulator layer; a dielectric layer substantially surrounding the reflector layer; and an absorber layer substantially surrounding the dielectric layer; wherein the insulator layer has an effective thickness for substantially preventing corrosion of the pigment flake. 54. The pigment flake of claim 53, further comprising a transparent overlayer coating surrounding the absorber layer. 55. A magnetic color shifting pigment composition comprising a plurality of color shifting pigment flakes the pigment flakes having a multilayer structure substantially the same as the pigment flake defined in claim 53. 56. A magnetic color-shifting colorant composition, comprising: a pigment medium; and a plurality of colorshifting pigment flakes dispersed in the pigment medium, the pigment flakes having a multilayer structure substantially the same as the pigment flake defined in claim 53. 57. A magnetic color shifting pigment flake, comprising: a central magnetic layer having a first major surface and an opposing second major surface; a first insulator layer comprising an oxide film over the first major surface of the magnetic layer; a second insulator layer comprising an oxide film over the second major surface of the magnetic layer; a first reflector layer comprising aluminum over the first insulator layer; a second reflector layer comprising aluminum over the second insulator layer; a first dielectric layer over the first reflector layer, a second dielectric layer over the second reflector layer; a first absorber layer over the first dielectric layer; and a second absorber layer over the second dielectric layer; wherein the pigment flake exhibits a discrete color shift such that the pigment flake has a first color at a first angle of incident light or viewing and a second color different from the first color at a second angle of incident light or viewing. 58. The pigment flake of claim 57, wherein the first and second insulator layers comprise aluminum oxide. 59. The pigment flake of claim 57, wherein the first and second insulator layers comprise an oxide of the magnetic layer. 60. The pigment flake of claim 57, wherein the first insulator layer comprises aluminum oxide, and the second insulator layer comprises an oxide of the magnetic layer.