Claims
- 1. Marking particles comprising a first polymer, a second polymer, a chelating agent, and a spiropyran material of the formula wherein n is an integer representing the number of repeat —CH2— units and R is —H or —CH═CH2, and wherein said particles comprise a core containing the first polymer in which is dispersed the chelating agent and the spiropyran and encapsulated within a shell of the second polymer formulated by an interfacial polymerization.
- 2. Marking particles according to claim 1 wherein the spiropyran material is of the formula wherein n is an integer of from about 2 to about 8.
- 3. Marking particles according to claim 1 wherein the spiropyran material is of the formula wherein n is an integer of from about 2 to about 8.
- 4. Marking particles according to claim 1 wherein the spiropyran materials is of the formula
- 5. Marking particles according to claim 1 wherein the spiropyran material is present in the marking particles in an amount of at least about 0.01 percent by weight of the marking particles.
- 6. Marking particles according to claim 1 wherein the spiropyran material is present in the marking particles in an amount of at least about 0.05 percent by weight of the marking particles, and wherein the spiropyran material is present in the marking particles in an amount of no more than about 5 percent by weight of the marking particles.
- 7. Marking particles according to claim 1 wherein the chelating agent is a metal salt in the +2 state.
- 8. Marking particles according to claim 1 wherein the chelating agent is a salt of calcium, magnesium, zinc, or a transition metal.
- 9. Marking particles according to claim 1 wherein the chelating agent is present in the marking particles in an amount relative to the spiropyran material of at least about 1 mole of chelating agent for every 1 mole of spiropyran material.
- 10. Marking particles according to claim 1 wherein the chelating agent is present in the marking particles in an amount relative to the spiropyran material of at least about 2 moles of chelating agent for every 1 mole of spiropyran material, and wherein the chelating agent is present in the marking particles in an amount relative to the spiropyran material of no more than about 10 moles of chelating agent for every 1 mole of spiropyran material.
- 11. Marking particles according to claim 1 wherein the spiropyran material is incorporated into the backbone of the first polymer or the second polymer.
- 12. Marking particles according to claim 1 wherein the first polymer is a polymer of monomers selected from styrene, α-methylstyrene, vinyl toluene, n-alkyl methacrylates, n-alkyl acrylates, branched alkyl methacrylates, branched alkyl acrylates, chlorinated olefins, vinyl-phenolic materials, alkoxy alkoxy alkyl acrylates, alkoxy alkoxy alkyl methacrylates, cyano alkyl acrylates, cyano alkyl methacrylates, alkoxy alkyl acrylates, alkoxy alkyl methacrylates, methyl vinyl ether, maleic anhydride, butadiene, ethylene, vinylacetate, isobutylene, isoprene, or mixtures thereof.
- 13. Marking particles according to claim 1 wherein the core further comprises a wax.
- 14. Marking particles according to claim 13 wherein the wax is present in the marking particles in an amount of at least about 0.5 percent by weight of the core and wherein the wax is present in the marking particles in an amount of no more than about 20 percent by weight of the core.
- 15. Marking particles according to claim 13 wherein the wax is candelilla wax, bees wax, sugar cane wax, carnuba wax, paraffin wax, or mixtures thereof.
- 16. Marking particles according to claim 1 wherein the second polymer is prepared by interfacial polymerization of (a) an organic soluble shell monomer selected from sebacoyl chloride, terephthaloyl chloride, phthaloyl chloride, isophthaloyl chloride, azeloyl chloride, glutaryl chloride, adipoyl chloride, hexamethylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, trans-1,4-cyclohexane diisocyanate, 4,4′-methyldiphenyl diisocyanate, 1,3,5-benzenetricarboxylic acid chloride, 4,4′-methyldiphenyl diisocyanate, tris(isocyanatophenyl) thiophosphate, or mixtures thereof, and (b) an aqueous soluble monomer selected from 1,6-hexanediamine, 1,4-bis(3-aminopropyl)piperazine, 2-methylpiperazine, m-xylene-α,α′-diamine, 1,8-diamino-ρ-menthane, 3,3′-diamino-N-methyldipropylamine, 1,3-cyclohexanebis(methylamine), 1,4-diaminocyclohexane, 2-methylpentanediamine, 1,2-diaminocyclohexane, 1,3-diaminopropane, 1,4-diaminobutane, 2,5-dimethylpiperazine, piperazine, fluorine-containing 1,2-diaminobenzenes, N,N′-dimethylethylenediamine, diethylenetriamine, bis(3-aminopropyl)amine, tris(2-aminoethyl)amine, or mixtures thereof.
- 17. Marking particles according to claim 1 wherein the second polymer is selected from polyureas, polyurethanes, polyesters, thermotropic liquid crystalline polyesters, polycarbonates, polyamides, polysulfones, poly(urea-urethanes), poly(ester-amides), poly(urea-amides), or mixtures thereof.
- 18. Marking particles according to claim 1 wherein the first polymer is present in an amount of from about 35 to about 90 percent of the marking particles and wherein the second polymer is present in an amount of from about 5 to about 50 percent by weight of the marking particles.
- 19. Marking particles according to claim 1 further comprising a charge control agent.
- 20. Marking particles according to claim 1 further comprising a colorant.
- 21. Marking particles according to claim 1 wherein the marking particles are prepared by a process which comprises (a) preparing a core material comprising (1) the spiropyran, (2) the chelating agent, (3) either (i) at least one core monomer and a free radical initiator, (ii) at least one core polymer, or (iii) a mixture of (i) and (ii), and (4) a first shell monomer; (b) forming an organic liquid phase containing the core material which is dispersed into an aqueous phase containing a water soluble surfactant and a second shell monomer to form an oil in water suspension; (c) encapsulating the core material within a polymeric shell by means of an interfacial polymerization reaction between the first shell monomer and the second shell monomer; and (d) subsequent to the interfacial polymerization reaction, optionally polymerizing the core monomers via free radical polymerization.
- 22. A developer composition comprising marking particles according to claim 1 and carrier particles.
- 23. A developer composition according to claim 22 wherein the marking particles are present in an amount of at least about 1 percent by weight of the carrier particles, and wherein the marking particles are present in an amount of no more than about 5 percent by weight of the carrier particles.
- 24. A process which comprises (a) generating an electrostatic latent image on an imaging member, and (b) developing the latent image by contacting the imaging member with marking particles according to claim 1.
- 25. A process according to claim 24 further comprising effecting a photochromic change in at least some of the marking particles in the developed image from a first state corresponding to a first absorption spectrum to a second state corresponding to a second absorption spectrum.
- 26. A process according to claim 25 wherein a first portion of the marking particles is caused to shift from the first state to the second state and a second portion of the marking particles remains in the first state.
- 27. A process according to claim 25 wherein the marking particles in the second state subsequently are caused to undergo another photochromic change, thereby returning them to the first state.
Parent Case Info
Copending Application U.S. Ser. No. 09/864,386 pending, filed concurrently herewith, entitled “Photochromic Gyricon Display,” with the named inventors Daniel A. Foucher, Raj D. Patel, Naveen Chopra, Peter M. Kazmaier, Erwin Buncel, and James Wojtyk, the disclosure of which is totally incorporated herein by reference, discloses a display comprising an arrangement of a plurality of optically anisotropic rotatable elements, each of said rotatable elements having a surface in contact with an enabling fluid, said rotatable elements being electrically dipolar in the presence of the enabling fluid and thus being subject to rotation upon application of an electric field, said rotatable elements being free to rotate in place but not free to translate substantially so as to disrupt the arrangement of rotatable elements, wherein a first portion of said surface contains a mixture of a chelating agent and a spiropyran material of the formula
wherein n is an integer representing the number of repeat —CH2— units and R is —H or —CH═CH2, and wherein a second portion of said surface contains substantially no spiropyran.
Copending Application U.S. Ser. No. 09/864,902 pending, filed concurrently herewith, entitled “Photochromic Electrophoretic Ink Display,” with the named inventors Daniel A. Foucher, Raj D. Patel, Naveen Chopra, Peter M. Kazmaier, Erwin Buncel, and James Wojtyk, the disclosure of which is totally incorporated herein by reference, discloses an electrophoretic ink comprising a suspending fluid and, suspended in the suspending fluid, a plurality of particles comprising a mixture of a chelating agent and a spiropyran material of the formula
wherein n is an integer representing the number of repeat —CH2— units and R is —H or —CH═CH2, said particles being free to migrate within said suspending fluid under the influence of an electric field.
Copending Application U.S. Ser. No. 09/864,535 allowed, filed concurrently herewith, entitled “Marking Particles,” with the named inventors Daniel A. Foucher, Raj D. Patel, Naveen Chopra, and Peter M. Kazmaier, the disclosure of which is totally incorporated herein by reference, discloses marking particles comprising a resin, a chelating agent, and a spiropyran material which is of the formula
The marking particles are prepared by an emulsion aggregation process.
US Referenced Citations (18)
Foreign Referenced Citations (2)
Number |
Date |
Country |
459792 |
Apr 1991 |
EP |
469864 |
May 1992 |
EP |
Non-Patent Literature Citations (1)
Entry |
James T. C. Wojtyk, Peter M. Kazmaier and Erwin Buncel, Effects of Metal Ion Complexation on the Spiropyran-Merocyanine Interconversion: Development of a Thermally Stable Photo-Switch, Chem. Commun., 1998, p. 1703. |