THERMAL INDICATOR FOR DETECTING HEAT HISTORY

• Main Authors: HASHIMOTO HARUMI, HIRANO ISAMU
• Format: Patent
• Language: English
• Published: 19.07.1984
• Subjects: ADHESIVES; BEER; BIOCHEMISTRY; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS, ORSURGICAL ARTICLES; CHEMISTRY; COLOUR PRINTING; COMPOSITIONS OR TEST PAPERS THEREFOR; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL ORENZYMOLOGICAL PROCESSES; DISINFECTION, STERILISATION, OR DEODORISATION OF AIR; DYES; ENZYMOLOGY; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; HUMAN NECESSITIES; HYGIENE; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; LAKES; LINING MACHINES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS, OR SURGICALARTICLES; MEASURING; MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEICACIDS OR MICROORGANISMS; MEASURING QUANTITY OF HEAT; MEASURING TEMPERATURE; MEDICAL OR VETERINARY SCIENCE; METALLURGY; METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS INGENERAL; MICROBIOLOGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; MORDANTS; MUTATION OR GENETIC ENGINEERING; NATURAL RESINS; ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES; PAINTS; PERFORMING OPERATIONS; PHYSICS; POLISHES; PRINTING; PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; PROCESSES OF PREPARING SUCH COMPOSITIONS; SPIRITS; STAMPS; TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION; TECHNICAL SUBJECTS COVERED BY FORMER USPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ARTCOLLECTIONS [XRACs] AND DIGESTS; TESTING; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR; TRANSPORTING; TYPEWRITERS; VINEGAR; WINE

PURPOSE:To provide the titled thermal indicator which clearly exhibits a change in color tone corresponding to heat history, by combining an azo dye with an epoxy compd. through a separator composed of a specified heat-fusible material. CONSTITUTION:A separator of 0.5-200mu in film thickness which is non-reactive with azo dye and epoxy compd. to be used and composed of a heat-fusible (or heat softening) material having a softening point of 50-300 deg.C, such as vinyl acetate resin or polyvinyl alcohol, is chosen according to the conditions of use. Ink contg. an azo dye of the formula (wherein n is 0, 1; X is a bivalent residue contg. S and/or N; Y is an enamine residue or an aniline derivative residue capable of coupling at para position) is mixed with an epoxy compd. which is microencapsulated by enclosing it in said separator. A support such as paper is coated with the mixture to obtain a thermal indicator for detecting heat history.