Abstract: A method for producing a reversible thermochromic display composed of multiple, overlapping color images. In accordance with the invention, a plurality of overlapping colored image layers are formed on a support, at least one of which layers provides a reversible thermochromic image. Each of the images on the various layers has a different visual density, and at least one reversible thermochromic image changes color at a temperature below or above a predetermined temperature and provides a color which is more intense and more easily discernible than the colors of the other ones of the images.

Abstract: A thermochromic material is described which comprises (a) an electron-donating, chromatic organic compound, (b) a compound capable of reversibly accepting an electron or electrons from the electron-donating, chromatic organic compound, (c) a compound controlling the temperature and sensitivity of coloration/decoloration of the thermochromic material and (d) a N-radical, P-radical, O-radical or S-radical cationic compound having an aromatic ring or rings which improves by light-fastness.

Abstract: A reversible thermochromic material is disclosed in the application. The material is comprised of (A) an electron-donating chromatic organic compound and (B) an acidic phosphoric acid ester compound or metal salt thereof, wherein Components (A) and (B) are contained in a weight ratio of 1:1/10 to 50 by weight. The material may also contain a third Component (C) for controlling the temperature of coloration/decoloration of the thermochromatic material. The thermochromatic material undergoes reversible metachromatism at a temperature within the range of -50.degree. C. to 120.degree. C. Furthermore, the reversible thermochromic material may be contained within microcapsules.

Abstract: A process for producing a reduced keratinous substance having a high adsorptive power for cationic substances, which comprises reducing a substance containing keratin as a main ingredient under alkaline conditions to cleave the disulfide linkages of the keratin, dissolving the reduced keratin in an aqueous medium containing urea or thiourea in a concentration of less than 5 moles/liter, and then acidifying the resulting solution to precipitate the dissolved reduced keratin under such conditions that the thiol side-chains present in the reduced keratin do not substantially undergo oxidation. The reduced keratinous substance is especially useful as a heavy metal ion capturing agent.

Abstract: This invention relates to a method for preparing paper board having excellent wet tensile strength and compression strength, which comprises (a) having paper board impregnated or coated with a mixture of an unsaturated vinyl ester prepolymer having a molecular weight of 300 to 3000 and having at least one hydroxyl group at the .beta.-position with respect to an ester bond in the molecule with at least one monomer selected from the group of methylacrylate, ethylacrylate and butylacrylate in a mixing weight ratio of 10:90-40:60, and (b) irradiating the paper board having the resinous mixture with electrons to cure the resinous mixture.

Abstract: An excellent thermochromic material exhibiting a sharp and reversible metachromatism at temperatures within a range of from -40.degree. to 80.degree. C can be formed from (A) an electron-donating, chromatic organic compound; (B) a compound containing a phenolic hydroxyl group; (C) a compound selected from the group consisting of higher aliphatic monovalent alcohols; and (D) a compound selected from the group consisting of higher aliphatic monovalent acid alcohol esters. The excellent thermochromic characteristics of such a thermochromic material can be further improved when it is occluded in fine microcapsules having a size not exceeding 50 .mu.. Thermochromic polymers, thermochromic printing inks, thermochromic writing instruments, thermochromic paints and thermochromic sheets having excellent thermochromatic characteristics and wide utility can be prepared from such a thermochromic material or microencapsulated thermochromic material.