Security articles comprising multi-responsive physical colorants
First Claim
1. A security article comprising a matrix component in which:
- (A) at least one particle scattering colorant is dispersed; and
(B) at least one luminescent substance is dispersed;
wherein;
(1) said at least one particle scattering colorant comprises particles selected from the group consisting of a semiconductor, metallic conductor, metal oxide, metal salt or mixture thereof;
(2) said at least one particle scattering colorant has an average cross-sectional size in the smallest dimension of less than about 0.2 micron;
(3) said polymer matrix component is substantially non-absorbing in the visible region of the spectrum;
(4) said particle scattering colorant has a minimum in the transmitted light intensity ratio in the 380 to 750 nanometer range that is shifted at least by 10 nanometers compared with that obtained for the same semiconductor, metallic conductor, metal oxide, metal salt or mixture thereof having an average particle size above about 20 microns; and
(5) said luminescent substance is selected from the group consisting of at least one fluorescent substance, at least one phosphorescent substance, mixtures of at least one fluorescent and at least one phosphorescent substance, wherein said luminescent substance exhibits a luminescent spectral response peak when excited by at least one wavelength selected from the electromagnetic spectral region of from about 200 to about 2,000 nanometers.
1 Assignment
0 Petitions
Accused Products
Abstract
Security articles comprising elements such as filaments, fibers, including hollow fibers, and threads and thin transverse sections and chopped versions thereof, wherein such elements are dispersed within the articles. Particle scattering and luminescent technology is employed based on scattering, electronic, magnetic and/or light properties to provide compound physical coloration responsive to various portions of the electromagnetic spectrum, including ultraviolet, ambient and infrared. The coloration effects can be highly stable or dependent on specific switching effects linked to, e.g., thermal exposure or actinic radiation. The security articles result in advanced levels of security to avoid counterfeiting of objects including banknote and currency paper, stock and bond certificates, identification, credit, debit and ATM cards, drivers'"'"' licenses and bar codes.
73 Citations
65 Claims
-
1. A security article comprising a matrix component in which:
-
(A) at least one particle scattering colorant is dispersed; and
(B) at least one luminescent substance is dispersed;
wherein;
(1) said at least one particle scattering colorant comprises particles selected from the group consisting of a semiconductor, metallic conductor, metal oxide, metal salt or mixture thereof;
(2) said at least one particle scattering colorant has an average cross-sectional size in the smallest dimension of less than about 0.2 micron;
(3) said polymer matrix component is substantially non-absorbing in the visible region of the spectrum;
(4) said particle scattering colorant has a minimum in the transmitted light intensity ratio in the 380 to 750 nanometer range that is shifted at least by 10 nanometers compared with that obtained for the same semiconductor, metallic conductor, metal oxide, metal salt or mixture thereof having an average particle size above about 20 microns; and
(5) said luminescent substance is selected from the group consisting of at least one fluorescent substance, at least one phosphorescent substance, mixtures of at least one fluorescent and at least one phosphorescent substance, wherein said luminescent substance exhibits a luminescent spectral response peak when excited by at least one wavelength selected from the electromagnetic spectral region of from about 200 to about 2,000 nanometers. - View Dependent Claims (3, 4, 5, 12, 13, 14, 17, 18, 19, 20, 21, 22, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64)
-
-
2. A security article comprising at least one first composition and at least one second composition:
-
(A) said first composition comprising a solid first matrix component, a particle scattering colorant and at least one luminescent substance dispersed therein;
(B) said at least one second composition comprising a polymer second matrix component, and a colorant selected from the group consisting of an electronic transition colorant, dye and pigment dispersed therein;
(C) said at least one first composition being either;
(1) disposed on and substantially exterior to said second composition on at least one side of the article;
or(2) said first and second compositions are substantially mutually interpenetrating;
wherein;
(i) there exists at least one incident visible light wavelength and one incident light angle such that said first composition absorbs less than about 90% of the light incident on said article;
(ii) the absorption coefficient of said at least one first composition is less than about 50% of that of said second composition at a wavelength in the visible region of the spectrum;
(iii) the highest absorption peak of said particle scattering colorant does not fall in the visible region of the spectrum;
(iv) said luminescent substance is selected from the group consisting of at least one fluorescent substance, at least one phosphorescent substance, and a mixture of at least one fluorescent and at least one phosphorescent substance, wherein said luminescent substance exhibits a luminescent spectral response peak when excited by one or more wavelength selected from the electromagnetic spectral region of about 200 to about 2,000 nanometers; and
(v) either;
(a) said particle scattering colorant has a refractive index that matches that of said first matrix component at a wavelength in the visible and has an average particle size of less than about 2000 microns;
or(b) the average refractive index of said particle scattering colorant differs from that of said first matrix component by at least about 5% in the visible wavelength range, the average particle size of said particle scattering colorant in the smallest dimension is less than about 2 microns, and said particle scattering colorant, when dispersed in a colorless, isotropic liquid having a substantially different refractive index, is characterized at visible wavelengths as having an effective maximum absorbance that is at least about 2 times the effective minimum absorbance. - View Dependent Claims (6, 7, 8, 9, 10, 11, 15, 16, 23, 24, 36, 37, 38, 39, 52, 53)
-
-
65. A specific embodiment of the subject invention can be described as follows:
1. A security article comprising a matrix component in which;
(A) at least one particle scattering colorant is dispersed; and
(B) at least one luminescent substance is dispersed;
wherein;
(1) said at least one particle scattering colorant comprises particles selected from the group consisting of a semiconductor, metallic conductor, metal oxide, metal salt or mixture thereof;
(2) said at least one particle scattering colorant has an average cross-sectional size in the smallest dimension of less than about 0.2 micron;
(3) said polymer matrix component is substantially non-absorbing in the visible region of the spectrum;
(4) said particle scattering colorant has a minimum in the transmitted light intensity ratio in the 380 to 750 nanometer range that is shifted at least by 10 nanometers compared with that obtained for the same semiconductor, metallic conductor, metal oxide, metal salt or mixture thereof having an average particle size above about 20 microns; and
(5) said luminescent substance is selected from the group consisting of at least one fluorescent substance, at least one phosphorescent substance, mixtures of at least one fluorescent and at least one phosphorescent substance, wherein said luminescent substance exhibits a luminescent spectral response peak when excited by at least one wavelength selected from the electromagnetic spectral region of from about 200 to about 2,000 nanometers; and
(6) said particle scattering colorant particles comprise a metallic conductor selected from the group consisting of gold, platinum, copper, aluminum, lead, palladium, silver, rhodium, osmium, iridium, and alloys and mixtures thereof;
(7) said matrix component is selected from the group consisting of polymers, cellulosic compositions and glasses;
wherein;
(a) said luminescent substance comprises at least one fluorescent substance and at least one phosphorescent substance having afterglow characteristics;
(b) said at least one fluorescent substance and said at least one phosphorescent substance having afterglow characteristics are present in said matrix at a total concentration of from about 0.5 to about 15 weight percent;
(c) said article is selected from the group consisting of filaments, fibers, film, slit film, dots and fibrils, said article adapted for use in connection with an object;
(d) said object comprising at least one structural element adapted to accept on at least one surface thereof, information in a form selected from the group consisting of at least one image, typeface and a mixture of at least one image and typeface; and
(e) said object is selected from the group consisting of;
currency, banknotes, negotiable instruments, passports, licenses, identification documents, credit cards, debit cards and bar codes.
Specification