Microencapsulated photochromic material, process for its preparation and a water-base ink composition prepared therefrom
AssigneesJapan Capsular Products, Inc., Mitsubishi Kasei Corporation
InventorsMasayuki Nakanishi, Takashi Iwasaki, Shuichi Maeda
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Abstract
This invention relates to a microencapsulated photochromic material and a process for its preparation. More particularly, it relates to a microencapsulated photochromic material having a good durability and a process for its preparation. The present invention further relates to a water-base ink composition comprising said microencapsulated photochromic material.
Claims10
A microencapsulated photochromic material comprising an effective amount of a spirooxazine compound in microcapsules in the form of a solution, said compound being of the Formula ##STR64## wherein R.sup.1, R.sup.2 and R.sup.3 each represent an optionally substituted alkyl group, an optionally substituted alkenyl group, a cycloalkyl group, or an aryl group;
- R.sup.2 and R.sup.3 may bind to each other to form a ring;
- R.sup.4 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms;
- R.sup.1 optionally contains another spirooxazine ring via an alkylene or arylene group, X and Y each represent an optionally substituted hydrocarbon aromatic ring or heterocyclic aromatic ring;
- and Z represents an oxygen atom or a sulfur atom.
A process for the production of a microencapsulated photochromic material which comprises dissolving a spirooxazine compound in a solvent, which has a boiling point of 40 to 160.degree. C. and a solubility in water at 20.degree. C. of 15% by weight or below, microencapsulating the solution thus obtained and vaporizing most of the solvent from the capsules during or after the above procedure, while leaving an effective amount of said spirooxazine compound and a trace amount of said solvent therein, said spirooxazine compound comprising ##STR65## wherein R.sup.1, R.sup.2 and R.sup.3 each represent an optionally substituted alkyl group, an optionally substituted alkenyl group, a cycloalkyl group, or an aryl group;
- R.sup.2 and R.sup.3 may bind to each other to form a ring;
- R.sup.4 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms;
- R.sup.1 optionally contains another spirooxazine ring via an alkylene or arylene group, X and Y each represent an optionally substituted hydrocarbon aromatic ring or heterocyclic aromatic ring;
- and Z represents an oxygen atom or a sulfur atom.
A water-base ink composition comprising an aqueous medium, a colorant and a vehicle as major components, wherein said colorant is obtained by microencapsulating an effective amount of a spirooxazine compound solution, an aqueous emulsion resin is used as said vehicle and the pH value of said ink composition is adjusted to 5 or above, said spirooxazine compound comprising ##STR66## wherein R.sup.1, R.sup.2 and R.sup.3 each represent an optionally substituted alkyl group, an optionally substituted alkenyl group, a cycloalkyl group, or an aryl group;
- R.sup.2 and R.sup.3 may bind to each other to form a ring;
- R.sup.4 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms;
- R.sup.1 optionally contains another spirooxazine ring via an alkylene or arylene group, X and Y each represent an optionally substituted hydrocarbon aromatic ring or heterocyclic aromatic ring;
- and Z represents an oxygen atom or a sulfur atom.
Dependencies are inferred from the claim text.