Colored articles and compositions and methods for their fabrication

• US 20030083429A1
• Filed: 12/03/2002
• Published: 05/01/2003
• Est. Priority Date: 09/28/1995
• Status: Active Grant

• Current Assignee: Alliedsignal Inc.
• Original Assignee: Alliedsignal Inc.
• Inventors: Baughman, Ray, Moulton, Jeffrey, Smith, Tammy Lynn, Martin, Mary Frances, Choi, Wonsik
• Granted Patent: US 6,730,399 B2
• Time in Patent Office: Days
• US Class Current: 524/779
• CPC Class Codes: B29C 41/00 Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor with compacting pressure B29C43/00 ; by lay-up of reinforcement of substantial or continuous length B29C70/30
• CPC Class Codes: B32B 27/20 using fillers, pigments, thixotroping agents
• CPC Class Codes: B32B 5/16 characterised by features of a layer formed of particles, e.g. chips, powder or granules layer formed of natural mineral particles B32B19/00; layer being formed of wood fibres, chips or particles B32B21/02
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: B41M 5/267 Marking of plastic artifacts, e.g. with laser
• CPC Class Codes: B41M 5/28 using thermochromic compounds or layers containing liquid crystals, microcapsules, bleachable dyes or heat- decomposable compounds, e.g. gas- liberating B41M5/38271 takes precedence
• CPC Class Codes: C08J 3/20 Compounding polymers with additives, e.g. colouring
• CPC Class Codes: C08J 5/18 Manufacture of films or sheets
• CPC Class Codes: D01D 5/24 with a hollow structure; Spinnerette packs therefor D01D5/38 takes precedence; producing tubes of plastic material B29D; addition of agents forming hollow filaments D01F1/08
• CPC Class Codes: D01F 1/04 Pigments
• CPC Class Codes: D01F 6/04 from polyolefins
• CPC Class Codes: D01F 6/60 from polyamides from polyamino acids or polypeptides D01F6/68
• CPC Class Codes: D01F 8/04 from synthetic polymers
• CPC Class Codes: D01F 8/12 with at least one polyamide as constituent
• CPC Class Codes: G02B 5/206 comprising particles embedded in a solid matrix
• CPC Class Codes: G02B 5/223 containing organic substances, e.g. dyes, inks or pigments
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G03C 7/12 by photo-exposure photomechanical production of optical colour artifacts such as colour screens, for purposes other than for additive colour photography G03F7/0007
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture
• CPC Class Codes: Y10T 428/162 Transparent or translucent layer or section
• CPC Class Codes: Y10T 428/25 : Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/257 : Iron oxide or aluminum oxide
• CPC Class Codes: Y10T 428/2913 : Rod, strand, filament or fiber
• CPC Class Codes: Y10T 428/2927 : including structurally defined particulate matter
• CPC Class Codes: Y10T 428/2929 : Bicomponent, conjugate, composite or collateral fibers or filaments [i.e., coextruded sheath-core or side-by-side type]
• CPC Class Codes: Y10T 428/2935 : Discontinuous or tubular or cellular core
• CPC Class Codes: Y10T 428/2938 : Coating on discrete and individual rods, strands or filaments
• CPC Class Codes: Y10T 428/2973 : Particular cross section
• CPC Class Codes: Y10T 428/2975 : Tubular or cellular
• CPC Class Codes: Y10T 428/2978 : Surface characteristic
• CPC Class Codes: Y10T 428/298 : Physical dimension
• CPC Class Codes: Y10T 428/2982 : Particulate matter [e.g., sphere, flake, etc.]
• CPC Class Codes: Y10T 428/2991 : Coated
• CPC Class Codes: Y10T 428/2993 : Silicic or refractory material containing [e.g., tungsten oxide, glass, cement, etc.]
• CPC Class Codes: Y10T 428/31725 : Of polyamide
• CPC Class Codes: Y10T 428/31728 : Next to second layer of polyamide
• CPC Class Codes: Y10T 428/31732 : At least one layer is nylon type

Abstract

This invention provides improved methods and compositions for achieving material coloration using particle scattering. These coloration effects can be designed to be either highly stable or dependent upon the switching effects of either temperature, integrated thermal exposure, moisture absorption, or exposure to actinic radiation. Articles employing materials with these coloration effects are described. Composition comprise a solid, light-transmitting matrix component having a non-liquid particle scattering colorant dispersed. Articles are produced wherein another solid second matrix component has an electronic transition colorant dispersed therein and the first and second compositions are disposed on one another and optionally interpenetrate each other. Colored articles are produced in the form of fibers, films and molded articles.

Claims

1. A composite article comprising a first composition and a second composition, the first composition comprising a solid first matrix component having a non-liquid particle scattering colorant dispersed therein, and a second composition comprising a solid second matrix component having an electronic transition colorant, dye or pigment dispersed therein;

the first composition being either disposed on and substantially exterior to the second composition on at least one side of the article or the first and second compositions are substantially mutually interpenetrating;

wherein there exists at least one incident visible light wavelength and one incident light angle such that the first composition absorbs less than about 90% of the light incident on the article;

wherein the absorption coefficient of the first composition is less than about 50% of that of the second composition at a wavelength in the visible region of the spectrum;

wherein the highest absorption peak of the particle scattering colorant does not fall in the visible region of the spectrum; and

wherein either (a) the particle scattering colorant has a refractive index that matches that of the 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 the particle scattering colorant differs from that of the first matrix component by at least about 5% in the visible wavelength range, the average particle size of the particle scattering colorant in the smallest dimension is less than about 2 microns, and the 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.

2. The composite article of claim 1 wherein both the first and second matrix components comprise organic polymers.

3. The composite article of claim 1, wherein the first composition either absorbs or scatters more than about 50% of uniform radiation at the ultraviolet wavelength at which the second composition undergoes the maximum rate of color fading.

4. The composite article of claim 1 wherein the particle scattering colorant is substantially non-absorbing in the visible region.

5. The composite article of claim 1 wherein the refractive index of the particle scattering colorant is substantially different than that of the first matrix component at all wavelengths in the visible region of the spectrum and wherein at least about 50% of all particles of said particle scattering colorant have a smallest dimension that is less than about 0.25 microns.

6. The composite article of claim 1, wherein the average particle size for the particle scattering colorant is from about 0.01 to about 0.4 microns, the average ratio of maximum dimension to minimum dimension for individual particles of the particle scattering colorant is less than about four, and the refractive index of the particle scattering colorant is substantially different than that of the matrix at all wavelengths in the visible region of the spectrum.

7. The composite article of claim 2, wherein both first and second matrix components are polymers, the average particle size for the particle scattering colorant is less than about 1000 microns, both the first matrix component and the particle scattering colorants are substantially optically isotropic, there exists a wavelength in the visible region of the spectrum at which the refractive index of the first matrix component substantially equals that of the particle scattering colorant, the refractive index difference of the first matrix component and the particle scattering colorant is substantially dependent on wavelength in the visible range, and the first matrix composition is substantially non-absorbing at wavelengths in the visible region of the spectrum.

8. The composite article of claim 7 wherein the difference in n_F−

n_C for the particle scattering colorant and for the first matrix component is greater in absolute magnitude than 0 001, wherein n_F and n_C are the refractive indices of the particle scattering colorant and the first matrix component at 486.1 nm and 656.3 nm respectively.

9. The composite article of claim 2 wherein at least one of the first and second matrix components comprises one or more materials selected from the group consisting of a polyamide, polyester, polyolefin, polyvinyl, acrylic, polysulfone, polycarbonate, polyarylate and polystyrene.

10. The composite article of claim 1 wherein the first matrix component and the second matrix component are substantially mutually interpenetrating and where α

_ev_eV_e for the second composition and α

_sv_sV_s for the first composition differ by less than a factor of ten at a wavelength in the visible region;

wherein α

_e is the absorption coefficient for the electronic transition colorant;

α

_s is the effective absorption coefficient for the particle scattering colorant;

v_s and v_e are respectively the volumes of the first and second compositions; and

V_s and V_e are respectively the volume fraction of the first composition that is the particle scattering colorant and the volume fraction of the second composition that is the electronic transition colorant.

11. The composite article of claim 1 wherein the first composition is disposed on and is substantially exterior to the second matrix composition on at least one side of the article, the second composition contains an electronic transition colorant or a pigment, there exists a wavelength of visible light and a light incidence angle at which from about 10% to about 90% light transmission occurs through the first composition, and α

_et_eV_e is greater than 0.1 for the second composition;

wherein α

_e is the absorption coefficient at the wavelength in the visible region at which the maximum absorption occurs for the electronic transition colorant or the pigment;

t_e is the maximum thickness of the layer comprising the second composition; and

V_e is the volume fraction of the second composition that is the electronic transition colorant or pigment.

12. The composite article of claim 2 wherein the second matrix component comprises a phase which is substantially a colored form of elemental carbon.

13. The composite article of claim 1 which is a fiber.

14. The composite article of claim 1 wherein the first composition forms a fiber sheath that substantially covers a core that is the second matrix composition.

15. The composite article of claim 14 wherein the sheath and core have differing cross-sectional shapes.

16. The composite article of claim 15 in which the maximum ratio of orthogonal axial dimensions in cross-section for an outer surface of the sheath is less than about one-half of the corresponding ratio for the core.

17. The composite article of claim 14 where the sheath and core both have a maximum ratio of orthogonal axial dimensions in cross-section that exceeds two and the long axis directions in cross-section of sheath and core are unaligned.

18. An element comprising a plurality of composite articles according to claim 14, wherein such element has either spatially dependent coloration for individual composite articles or differing coloration for different composite articles as a result of variations in the cross-section of the sheath or the cross-section of the core.

19. The element of claim 18 that is a yarn.

20. A process for making the yarn of claim 19 comprising assembling a plurality of the composite articles directly from a multi-hole spinneret assembly, wherein each spinneret hole comprises a core feed and a sheath feed which continuously envelopes the core feed.

21. The process of claim 20 comprising causing composite article coloration differences either by a pressure variation between the sheath and the core feeds or by varying the shapes of individual spinneret holes.

22. An element that is a rope, harness, or tire that comprises the composite article of claim 14.

26. The composite article of claim 2 in which the particle scattering colorant in the first composition comprises an inorganic composition.

27. The composite article of claim 26 wherein the inorganic composition comprises one or more materials selected from the group consisting of bismuth oxychloride;

titanium dioxide;

antimony trioxide;

barium titanate;

solid solutions of BaTiO₃ with SrTiO₃, PbTiO₃, BaSnO₃, CaTiO₃, or BaZrO₃;

potassium lithium niobate;

aluminum hydroxide;

zirconium oxide;

colloidal silica, lithium niobate;

lithium tantalate;

proustite;

zinc oxide;

alpha-zinc sulfide; and

beta-zinc sulfide.

28. The composite article of claim 1 wherein the particle scattering colorant comprises a ferroelectric, antiferroelectric, or photoferroelectric material.

29. The composite article of claim 28 in which the ferroelectric material is a relaxor ferroelectric ceramic.

30. The composite article of claim 29 wherein said relaxor ferroelectric ceramic has a Curie transition temperature of from about 250°

K to about 350°

K.

31. The composite article of claim 29 wherein said relaxor ferroelectric ceramic has the form A(BF_1/2BG_1/2)O₃ where BF and BG represent the atom types on the B sites in a lead titanate type of structure, or is an alloy of one or more compositions of such form with another ceramic composition, and wherein A is Pb and BF_1/2 and BG_1/2 are independently Sc_1/2, Ta_1/2, Fe_1/2, or Nb_1/2.

32. The composite article of claim 29 wherein said relaxor ferroelectric ceramic has the form A(BF_1/3BG_2/3)O₃, where BF and BG represent the atom types on the B sites in a lead titanate type of structure, or is an alloy of one or more compositions of such form with another ceramic composition, and wherein A is Pb, BF_1/3 is Mg_1/3, Ni_1/3 or Zn_1/3, and BG_2/3 is Nb_2/3.

33. A composite article of claim 32 wherein the relaxor ferroelectric ceramic comprises Pb(Mg_1/3Nb_2/3)O₃.

34. The composite article of claim 33 which includes up to 35 mole percent of alloyed PbTiO₃.

38. The composite article of claim 1 which is in the form of a film in which a layer of the first composition is joined to either one side or to both opposite sides of the second composition.

39. An element which is a light source, visual display, sign, or switchable screen comprising the composite article of claim 38 wherein the composite article is either planar or non-planar, and comprises either a particle scattering colorant, an electronic transition colorant, a dye, a pigment, or a matrix that is switchable in either refractive index or absorption coefficient.

40. The element of claim 39 wherein the composite article is switchable as a result of an applied electric field.

41. The element of claim 39 wherein the composite article comprises a ferroelectric, antiferroelectric, or photoferroelectric composition.

42. The composite article of claim 38 in which the first matrix component and the second matrix component both comprise an organic polymer.

43. The composite article of claim 42 which is in the form of film strips having a denier less than about 200 and a width-to-thickness ratio of at least about 5.

68. The composite article of claim 1 wherein the particle scattering colorant comprises gas-filled particles, a fluorinated carbon-containing composition, or a transparent carbon phase.

23. A fiber comprising a polymer matrix component in which particle scattering colorant particles are dispersed, wherein said particle scattering colorant comprises a semiconductor, metallic conductor, metal oxide or metal salt;

the particle scattering colorant has an average diameter in the smallest dimension of less than about 2 microns;

the polymer matrix component is substantially non-absorbing in the visible region of the spectrum; and

the particle scattering colorant has a minimum in the transmitted light intensity ratio in the 380 to 750 nm range that is shifted at least by 10 nm compared with that obtained for the same semiconductor or metallic conductor having an average particle size above about 20 microns.

24. The fiber of claim 23 wherein the particle scattering colorant comprises one or more colloidal particles selected from the group consisting of gold, platinum, copper, aluminum, tin, zinc, nickel, lead, palladium, silver, rhodium, osmium, iridium, and alloys thereof.

25. The fiber of claim 23, wherein the transmitted light intensity ratio has two minima in the wavelength region of the visible spectra and the particle distribution of the particle scattering colorant is mononodal.

35. A fiber composite comprising a polymer matrix having dispersed therein particles of one or materials selected from the group consisting of VO₂, V₂O₃, NiS, NbO₂, FeSi₂, Fe₃O₄, NbO₂, Ti₂O₃, Ti₄O₇, Ti₅O₉, and V₁₋

xM_xO₂, wherein M is W, Mo, Ta or Nb and x is less than about 0.1.

36. A composite article in fiber form comprising a polymer matrix having dispersed therein particles selected from the group consisting of ferroelectric, antiferroelectric and photoferroelectric particles.

37. The composite article of claim 36 further comprising an electronic transition colorant, a dye or a pigment.

44. A composition comprising at least two particle scattering colorants dispersed in a polymer matrix, wherein the particle scattering colorants are substantially non-absorbing in the visible spectral range;

the average refractive index of the particle scattering colorants differ by at least 10% at a wavelength in the visible range;

the relative volume ratio of the less concentrated of the particle scattering colorants to the more concentrated of the particle scattering colorants exceeds about 1/8, and the polymer matrix does not comprise an electronic transition colorant, a dye or a pigment.

45. The composition of claim 44 wherein at least one of the particle scattering colorants is a metal oxide.

46. The process of forming a composition which comprises ultrasonically irradiating either (a) a fluid monomer composite of either a particle scattering colorant or a precursor thereof in mixture with the monomer during polymerization of the monomer or (b) a polymer in a molten state and either a particle scattering colorant or a precursor thereof in mixture with the molten polymer.

47. A polymer composition comprising in admixture, a polymer matrix, at least one particle scattering colorant, and at least one electronic transition colorant, dye or pigment wherein (a) either the refractive index difference between the polymer matrix and the particle scattering colorant or the absorption spectra of the electronic transition colorant, dye or pigment undergoes substantial change as a result of one or more of a temperature change, humidity change, an electric field change, pressure change, exposure to a chemical agent, integrated thermal exposure, or exposure to either light or actinic radiation and (b) states exist in which either the average refractive index of the particle scattering colorant and the polymer matrix differ by at least 5% in the entire visible spectral region or the refractive index of the particle scattering colorant and the polymer matrix are matched at a wavelength in the visible spectra region.

48. The polymer composition of claim 47 which undergoes a detectable color change in response to one or more of a chemical agent, pressure, temperature, moisture pickup, or time-temperature exposure change, wherein the average refractive index of the particle scattering colorant and the polymer matrix differ by at least 5% in the entire visible spectra.

49. The composition of claim 47 wherein the electronic transition colorant, dye or pigment contains a photochromic anil, fulgide, or spiropyran.

50. The composition of claim 47 comprising one or materials selected from the group consisting of VO₂, V₂O₃, NiS, NbO₂, FeSi₂, Fe₃O₄, NbO₂, Ti₂O₃, Ti₄O₇, Ti₅O₉, and V₁₋

xM_xO₂, wherein M is W, Mo, Ta or Nb and x is less than about 0.1.

51. A polymer composition comprising a particle scattering colorant and an electronic transition colorant, a dye, a pigment or a matrix polymer that displays electronic transition coloration, wherein dichroism in the visible range results from either preferential orientation of the electronic transition colorant, the dye, the pigment or the matrix polymer.

52. A polymer composition either comprising a particle scattering colorant in a piezoelectric polymer matrix or comprising a piezoelectric particle scattering colorant in a fiber shaped polymer matrix, wherein neither the polymer matrix nor the particle scattering colorant significantly absorb in the visible range.

53. The polymer composition of claim 52 wherein both the said particle scattering colorant and the polymer matrix have a near vanishing anisotropy of refractive index in the unpoled state and where the average refractive index of the polymer matrix and the particle scattering colorant are substantially matched at a wavelength in the visible spectra region.

54. The polymer composition of claim 52 in the form of a fiber form and comprises a piezoelectric particle scattering colorant that is a ferroelectric, an antiferroelectric, or a photoferroelectric.

55. The polymer composition of claim 52 comprising an electronic transition colorant, a dye or a pigment.

56. The polymer composition of claim 55 wherein the particle scattering colorant and the electronic transition colorant, dye or pigment are in separate polymer matrices and wherein the polymer matrix that contains the particle scattering colorant is substantially exterior to the polymer matrix containing the electronic transition colorant, dye or pigment on at least one side of the article.

57. An article in the form of a film, fiber, or molded part comprising a particle scattering colorant dispersed in a polymer matrix, wherein the average particle size of the particle scattering colorant in its smallest dimension is less than about 2 microns and wherein either (a) the particle scattering colorant has a coating thereon and the refractive index of the coating differs from that of the polymer matrix by at least 10% at all wavelengths in the visible region of the spectrum or (b) the particle scattering colorant is comprised of a series of layers that differ in refractive indices between adjacent layers by at least 5%.

58. The article claim 57 wherein the coating comprises a material having an absorption peak at visible wavelengths and the volume of the coating is less than about 50% of the total volume of the particle of the particle scattering colorant.

59. The article of claim 58 wherein the average size of the particle scattering colorant is less than about 0.2 microns and the volume of the coating is less than about 20% of the total volume of the particle of the particle scattering colorant.

60. An article comprising a polymer having a particle scattering colorant dispersed therein, wherein said article comprises an anti-reflection coating.

61. The article of claim 60 that is in the form of either a fiber or a film.

62. A hollow polymeric fiber comprising a particle scattering colorant wherein either (a) the particle scattering colorant is disposed inside a hollow cavity of the fiber or (b) the particle scattering colorant is dispersed in a polymer matrix that is a sheath of the hollow polymeric fiber and either an internal surface or the internal hollow cavity of the hollow fiber is colored with a material that significantly absorbs light in the visible region of the spectrum.

63. The hollow polymeric fiber of claim 62 comprising a plurality of lateral holes extending from a core of the fiber to a surface of the fiber, wherein the average separation of adjacent holes is less than about 10 inches, and the average hole diameter is capable of imbibing a liquid into the fiber core at a pressure of less than 2000 psi.

64. The hollow fiber of claim 62 comprising an electronic transition colorant, a dye or a colorant.

65. A process of making a hollow fiber of claim 64 comprising melt spinning the hollow polymeric fibers and solution dyeing of the cavity of the hollow fiber.

66. The process of making a hollow polymer fiber of claim 62 that involves the imbibing of a colloidal solution of a particle scattering colorant within a cavity of said hollow fiber.

67. The hollow fiber of claim 62 comprising particles of a photoferroelectric in a low conductivity carrier fluid that is disposed within the fiber cavity.

69. The process of applying a deposition of a particle scattering colorant to an article which comprises xerographically depositing, plasma depositing, or powder depositing onto a substrate, a particle scattering colorant which does not substantially absorb in the visible region, wherein such process does not also simultaneously apply an electronic transition colorant, a dye or a pigment to the substrate.

70. The process of claim 69, wherein a particle scattering colorant is present in a fusible polymer matrix and is applied by xerographic deposition to a substrate that contains an electronic transition colorant, a dye or a pigment.

71. The process of claim 70, wherein the average refractive index of the particle scattering colorant differs from that of the said fusible polymer matrix by at least 10% in the visible wavelength range, the average particle size of the particle scattering colorant in the smallest dimension is less than 2 microns, and the particle scattering colorant, when dispersed in a colorless, isotropic liquid having a substantially different refraction index, is characterized at visible wavelengths as having an effective maximum absorbance that is at least 2 times the effective minimum absorbance.

72. An article comprising a particle scattering colorant inhomogeneously distributed in a polymer matrix, and an optional electronic transition colorant, dye or pigment wherein the inhomogeneous distribution of such particle scattering colorant is such that either (a) the predominant color variations are less frequent than every 200 microns or (b) optical properties are periodically varied on a dimensional scale comparable with the wavelengths of visible light.

73. A process for forming an article of claim 72, wherein either a magnetic field, an electric field, or patterned irradiation provides a non-uniform distribution of either the said particle scattering colorant or the optional electronic transition colorant, dye or pigment.

74. A method of decreasing the coloration of an article comprising a polymer matrix and a particle scattering colorant dispersed therein, the process comprising subjecting the article to irradiation, thermal heating, a chemical agent, or a mechanical deformation under conditions sufficient to alter scattering due to particle size.

75. A process for decreasing the coloration of the article according to claim 74 comprising either (a) subjecting the article to a thermal or irradiation process that either decreases the refractive index difference between the particle scattering colorant and the polymer matrix, eliminates a match at a visible wavelength of the refractive index of the particle scattering colorant and the polymer matrix, eliminates the particle scattering colorant from the polymer matrix by dissolution, evaporation, or chemical reaction, or provides particle aggregation for the particle scattering colorant or (b) subjecting the article to a mechanical process that causes either particle aggregation or a stress-induced chemical reaction of the particle scattering colorant.

76. A polymer composite comprising particles of a particle scattering colorant that is an aggregate of single primary particles having substantially uniform sizes in at least m dimensions, wherein (a) m is either two or three, (b) the primary particles form an array having translational periodicity in from one to m dimensions only within the particle scattering colorant, (c) the space between primary particles within the particle scattering colorant is a gas, a liquid, a solid, or a combination thereof, (d) the particle scattering colorants are dispersed in a matrix polymer, and (e) the volume fraction of these particle scattering colorants is less that about 75% of the total volume of the matrix polymer and particle scattering colorant.

77. The polymer composite of claim 76, wherein the average size of the individual primary particles is less than about 1000 nm in the smallest dimension and the translational periodicity of the primary particles in at least one dimension is from about 50 nm to about 2000 nm.

78. An article that is a polymer film, polymer fiber, or polymer molded part comprising the polymer composite of claim 76, wherein the average size of the particle scattering colorant particles in the smallest dimension is less than about one-third of the smallest dimension of the polymer article.

79. The process of forming an article of claim 78 comprising first forming the particle scattering colorant particles, and then commingling the particle scattering colorant particles with a polymer matrix material so as to not to substantially destroy the translational periodicity of the particle scattering colorant particles in all dimensions.

80. The polymer composite of claim 76, wherein the space between primary particles within the particle scattering colorant comprises either a liquid or a solid having a refractive index that differs from that of the primary particles by less than 5% in the visible spectral range.

81. A fiber or flexible film article containing an inorganic particle scattering colorant in a host polymer matrix, wherein both the particle scattering colorant and the polymer matrix have substantially isotropic optical properties, there exists a wavelength in the visible where the refractive index of the particle scattering colorant and the polymer matrix are matched, the average particle size of the particle scattering colorant is less than 2000 microns, and the refractive index difference between the polymer matrix and the particle scattering colorant significantly depends upon wavelength in the visible spectral range.

82. The article of claim 81 additionally comprising a coupling agent that is disposed at the interface between the particle scattering colorant and the polymer matrix.

83. The article of claim 82 wherein the coupling agent comprises a silane.

84. An article comprising an organic polymer matrix component in which are dispersed a particle scattering colorant and an electronic transition colorant or a pigment, wherein α

_eV_e for the electronic transition colorant or pigment and α

_sV_s for the particle scattering colorant differ by less than a factor of ten at a wavelength in the visible range and wherein either (a) the average refractive index of the particle scattering colorant differs from that of the said polymer matrix component by at least 5% in the visible wavelength range, the average particle size of the particle scattering colorant in the smallest dimension is less than about 2 microns, and the 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 or (b) the particle scattering colorant is either a colloidal semiconductor or metallic conductor whose minimum in transmitted light intensity ratio due to absorption is shifted at least by about 10 nm compared with that obtained for the same semiconductor or metallic conductor having an average particle size above about 20 microns and wherein α

_e is the absorption coefficient for the electronic transition colorant or pigment;

α

_s is the effective absorption coefficient for the particle scattering colorant; and

V_s and V_e are respectively the volume fraction of the total volume of polymer matrix component, particle scattering colorant, and electronic transition colorant or pigment that is the particle scattering colorant and the volume fraction of the total volume of polymer matrix component, particle scattering colorant, and electronic transition colorant or pigment that is the electronic transition colorant or pigment.

85. The article of claim 84 wherein α

_eV_e for the electronic transition colorant or pigment differs from α

_sV_s for the particle scattering colorant by less than a factor of about 3.

86. The article of claim 84 that is a melt-spun fiber.

87. The article of claim 86 that is a melt-spun fiber comprising a nylon polymer and a substantially non-absorbing inorganic particle scattering colorant having an average particle diameter of less than about 0.1 microns.

88. The article of claim 87 wherein the electronic transition colorant or pigment is a form of colored elemental carbon.

89. A process for producing a colored article comprising combining a colloidal particle scattering colorant with either a monomer or mixture of monomers and thereafter polymerizing the monomer or mixture of monomers by the application of sufficient heat or polymerizing irradiation in a three-dimensional shaped cavity to provide a colored shaped polymer article.

90. The process of claim 89, wherein the monomer or monomer mixture is thermally polymerized.

91. The process of claim 89, wherein the said colloidal particle scattering colorant is a colloidal metal.

92. The process of claim 90, wherein the monomer or monomer mixture comprises caprolactam and the colloidal particie scattering colorant is a colloidal metal.

93. A process for the manufacture of colored polymer fibers comprising forming a dispersion of a particle scattering colorant having an average particle size of less than 0.2 microns with a polymer matrix in the gel state and then subjecting the dispersion to fiber spinning and fluid extraction processes resulting in solidification of the polymer matrix in fiber form, wherein the particle scattering colorant has a refractive index that is at least 10% different from that of the solidified polymer matrix at a wavelength in the visible region.

94. The process of claim 93 wherein said particle scattering colorant comprises an inorganic composition that is substantially non-absorbing in the visible, the average particle size of the particle scattering colorant is less than about 0.2 microns, and further comprising incorporating an electronic transition colorant or a pigment in the dispersion prior to the spinning step.

95. The process of claim 93 wherein the matrix polymer comprises polyethylene.

96. The process of claim 93 wherein the particle scattering colorant is substantially absorbing in the visible region and the average particle size of the particle scattering colorant is less than about 0.02 microns.

97. A polymer film article comprising an optically isotropic polymer matrix and optically anisotropic plate-like particles of a particle scattering colorant wherein (a) the plate-like particles are preferentially oriented with particle plate planes parallel to the film surface, (b) the optic axis of the particle scattering colorant particles is normal to the particle plate plane, and (c) the ordinary refractive index of the particle scattering colorant is substantially matched with that of the polymer matrix at a wavelength in the visible region.

98. A polymer article comprising a polymer matrix material in which a particle scattering colorant is dispersed, wherein the refractive index of the particle scattering colorant and the refractive index of the polymer matrix material change in opposite directions for a given light polarization direction and wherein such changes result from a change in electric field, temperature, pressure, time-temperature exposure, humidity, or exposure to a chemical agent.

99. The polymer article of claim 98 that is in the form of either an indicator device or a display device that provides a color response.

100. A polymer article comprising a particle scattering colorant dispersed in a solid polymer matrix, wherein a color change of said article is produced by a change in the difference in the refractive index of the particle scattering colorant and the matrix upon exposure to visible, ultraviolet, or infrared radiation.

101. A process for monitoring the setting of a resin comprising dispersing a particle scattering colorant in the resin, subjecting the resin to conditions sufficient to cause the resin to set, and monitoring a change in coloration during resin setting.

102. A process for the manufacture of a shaped three-dimensional polymer article comprising assembling a series of layers, wherein said layers comprise a particle scattering colorant dispersed in a polymer matrix component and wherein either (a) the particle scattering colorant has a refractive index that matches that of the said polymer matrix component over a limited wavelength range in the visible region and the particle scattering colorant has an average particle size of less than about 2000 microns, (b) the average refractive index of the particle scattering colorant differs from that of the said polymer matrix component by at least 5% in the visible wavelength range, the average particle size of the particle scattering colorant in the smallest dimension is less than about 2 microns, and the 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, or (c) the particle scattering colorant is a colloidal particle of either a semiconductor or a metal that has an average diameter of less than about 40 nm.

103. The process of claim 102 wherein the series of layers is provided by patterned exposure thereof to infrared, ultraviolet, or visible light.

104. The process of claim 102, wherein the series of layers is provided by the patterned deposition of either a melt or solution phase that contains the particle scattering colorant.

105. The process of claim 103 wherein the layers are assembled by photopolymerization of a monomer or oligomer and the photopolymerized monomer or oligomer comprises a vinyl ether.

106. The process of claim 102 wherein the particle scattering colorant is either a colloidal metal or a colloidal metal oxide.

107. A process for producing a colored article comprising combining a metal salt with a monomer or polymer that is capable of being oxidized followed by thermal reaction to produce a colloidal particle scattering colorant within a polymer matrix.

108. The article produced by the process of claim 107.

109. The article of claim 108 which is in the form of a fiber or injection molded part.

110. The process of claim 107 wherein the metal salt is a salt of gold, silver, platinum, copper, nickel, tin, aluminum, lead, palladium, rhodium, osmium, iridium or alloys thereof.

114. The process of claim 107, wherein the oxidation of said monomer or polymer produces said colloidal particle scattering colorant.

111. A process for producing a colloidal particle scattering colorant comprising combining a reducible metal salt with a monomer or polymer.

112. An article produced according to the process of claim 111.

113. The article according to claim 112 which is in the form of a fiber or injection molded part.

115. The process of claim 111 wherein the oxidation of said monomer or polymer reduces said reducible metal salt.

116. A process for producing colloidal particle scattering colorants comprising combining a reducible metal salt with a reducing agent and a polymer followed by a thermal reaction.