JP2002294123A - Heat-sensitive ink and temperature hysteresis indicator using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat-sensitive ink used for mass-producing, conveniently in a simple way, a temperature hysteresis indicator which can correctly indicate whether or not it has a temperature hysteresis exceeding a certain temperature, by a distinct change in color tone, and can be stored without further changing the color tone. SOLUTION: The heat-sensitive ink contains microcapsules containing a particulate or powdery, a thermally meltable substance having a melting point equal to the temperature to be recorded and a particulate or powdery colorant which is diffusable in the thermal melt of the thermally meltable substance by dispersion or dissolution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to record whether or not a temperature history exceeding a predetermined temperature has passed, and to use a temperature-sensitive ink whose color tone changes irreversibly at a predetermined temperature. Temperature history indicator.

[0002]

2. Description of the Related Art Some products, such as processed foods, must be heated above a predetermined temperature during production. In addition, there are products such as pharmaceutical products and foodstuffs that deteriorate, decompose, or decay when the temperature exceeds a predetermined temperature during distribution or storage. There are also products such as electric equipment and electric parts, such as motors, which may fail or break due to overheating during use and cause danger such as fire.

Conventionally, a temperature indicating material indicated by a change in color tone has been used to detect whether or not a product has gone through a temperature history exceeding a predetermined temperature. Examples of such temperature indicating materials include, for example, JP-A-61-12784 and JP-A-61-14284.
Japanese Patent Application Publication No. JP-A-2005-115139 discloses a composition containing a heat-fusible substance and an acid-base indicator. This temperature indicator, after discoloration by heating,
It is reversible, returning to its original color when cooled. Therefore, when monitoring is lacking, it cannot be detected whether or not a predetermined temperature has been exceeded. Furthermore, it cannot be stored as a record of the temperature history.

Further, the irreversible label disclosed in Japanese Utility Model Publication No. 46-28235 has to be produced as a three-dimensional structure, and has low suitability.

Accordingly, the present applicant has filed a Japanese Patent Application No. 2000-12.
No. 4431, which is a mixture of a granular or powdery pigment and a granular or powdery heat-fusible substance having a melting point corresponding to the temperature to be recorded, wherein the change in color tone due to heating is irreversible. A temperature sensitive composition has been filed.

[0006] The temperature-sensitive composition is in the form of granules or powder. In order to produce a card-shaped indicator, in order to apply this composition to the substrate surface as it is, after squeezing the composition on the substrate, it must be coated with a film so as not to peel off and integrated. It is troublesome. When making this composition into an ink, it is necessary to select a vehicle or a solvent for the vehicle that does not dissolve the heat-meltable substance and the dye, and also prints with the obtained ink and print stability and storage stability after printing. Sex is not enough.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is possible to accurately display whether a temperature history exceeding a predetermined temperature has passed through a clear change in color tone, and to further change the color tone. An object of the present invention is to provide a temperature-sensitive ink used for easily mass-producing a temperature history indicator that can be stored as it is.

[0008]

According to the present invention, there is provided a temperature-sensitive ink comprising: a granular or powdery heat-fusible substance having a melting point corresponding to a temperature to be recorded; Microcapsules enclosing a dispersed or dispersible particulate or powdered pigment in the substance. The microcapsules are unevenly distributed.

The heat-fusible substance is a component that determines the discoloration temperature, has a melting point at a temperature to be recorded under normal pressure, and is encapsulated in microparticles in the form of particles or powder. When heated to a temperature equal to or higher than the melting point, the heat-fusible substance is heat-melted and changes from granular or powdery to liquid. The heat-fusible substances include fatty acid derivatives, alcohol derivatives, ether derivatives, aldehyde derivatives, ketone derivatives, amine derivatives, amide derivatives, nitrile derivatives, hydrocarbon derivatives,
At least one selected from thiol derivatives and sulfide derivatives is suitably used.

The pigment is in the form of particles or powder and is encapsulated in a microcapsule together with a heat-fusible substance. The dye is dispersed or dissolved and diffused in the hot-melt heat-fusible substance. Further, the pigment may be one in which the particle surface or powder surface of the pigment is wetted by this substance which has been melted by heat. As pigments, direct dyes, acid dyes, basic dyes, disperse dyes, reactive dyes, oil-soluble dyes, vat dyes, mordant dyes,
Examples include dyes exemplified by azoic dyes and sulfur dyes, pigments exemplified by organic pigments and inorganic pigments, and colored bodies. A wide range of dyes can be used in this temperature sensitive ink. These dyes may be used as a mixture of two or more kinds.
The dye preferably has a diameter of 0.001 μm to 5 mm. The pigment is preferably contained in the microcapsules in a ratio of 0.001 to 100 parts by weight with respect to 100 parts by weight of the heat-fusible substance.

The microcapsules are, for example, microparticles of about 0.01 μm to about 10 mm having a uniform outer wall and enclosing a granular or powdery pigment and a heat-fusible substance.

[0012] The outer wall of the microcapsule is made of a polymer compound selected from the group consisting of polyvinyl alcohol, polystyrene, silicone resin, epoxy resin, acrylic resin, urea resin, gelatin, methylcellulose, polyurethane, wax, gum arabic, dextrin and nylon. It is suitably implemented by being formed by.

The microcapsules are prepared by, for example, an interfacial polymerization method, an in-situ method, a phase separation method, an air suspension method, an electrostatic coalescence method, a spray coagulation method, and a submerged drying method.

Preferably, the microcapsules are contained in the temperature-sensitive ink at 10 to 70% by weight. When the amount is less than 10% by weight, the change in color tone is unclear, while when the amount is more than 70% by weight, the fixing force is reduced, so that application and printing on a substrate cannot be performed.

[0015] The temperature-sensitive ink preferably contains an ink vehicle. Examples of the ink vehicle include acrylic resin, phenol resin, nylon, ethyl cellulose, hydroxymethyl cellulose, polyvinyl alcohol, and carboxymethyl cellulose. Commercially available ink vehicles, PAS800 Medium, Aquaset Ink (both are brand names manufactured by Jujo Kako), High Set Mat Medium (brand name manufactured by Mino Group), V
AR-000 medium (trade name, manufactured by Teikoku Ink Mfg. Co., Ltd.) and Lamister R Medium (trade name, manufactured by Toyo Ink Co., Ltd.) may be used.

Examples of the ink vehicle include silica-based, epoxy-based, amino-based, urethane-based, urethane acrylate-based, epoxy acrylate-based, ether acrylate-based, alkyd-based, vinyl acetal-based, acrylic polyester, and acrylic ultraviolet curable resins. No. Commercially available vehicles include Daicure AK (manufactured by Dainippon Ink and Chemicals, Inc.), FDS New (manufactured by Toyo Ink Mfg. Co., Ltd.), Lake Cure TU4400 (manufactured by Jujo Chemical Co., Ltd.), and UVSPA Clear (manufactured by Teikoku Ink Mfg. Co., Ltd.) )) And UV8418 (manufactured by Seiko Advance Co., Ltd.).

The temperature-sensitive ink may contain a solvent that dissolves the ink vehicle. Solvents for this ink vehicle include, for example, water, ethanol, butanol, isopropyl alcohol, ethyl acetate, isoamyl acetate, methyl ethyl ketone, methyl isobutyl ketone, xylene, diethylbenzene, toluene, butyl cellosolve, ethyl cellosolve, mineral spirits, and even UV curable resins. If so, a monomer of the photosensitive resin may be used.

Further, the temperature-sensitive ink may contain a dispersing agent such as talc, magnesium carbonate, or silica, so that the coloring matter is further dispersed and the color tone change becomes clear. Dyes exemplified by direct dyes, acid dyes, basic dyes, disperse dyes, reactive dyes, oil-soluble dyes, architectural dyes, mordant dyes, azoic dyes, and sulfur dyes are used for temperature-sensitive inks in order to amplify the change in color tone. , An organic pigment, or an inorganic pigment, which may contain an auxiliary colorant having a color indicating the color tone of the pigment and a contrasting color. Further, the temperature-sensitive ink may contain a wax or a surfactant for adjusting the fluidity and drying property of the ink.

The temperature history indicator of the present invention is obtained by printing the above-mentioned temperature-sensitive ink on a substrate.

Examples of the base material include paper such as plain paper, Japanese paper, and Kent paper; synthetic paper; wood such as hinoki wood; polypropylene, polyethylene terephthalate, acrylonitrile-butadiene-styrene resin, polycarbonate, and acrylic resin. Plastics.

This temperature history indicator has a card shape,
The label may be in the form of a sheet or a rod, or may be a label having an adhesive layer on the back surface.

The printing is performed by, for example, screen printing, offset printing, gravure printing, or brush coating.

The ink layer formed by printing this ink may be covered with a transparent or translucent resin laminate. For the laminate material, for example, polypropylene, polyethylene terephthalate, acrylonitrile-
Plastic films exemplified by butadiene-styrene resin, polycarbonate, and acrylic resin; printing media for lamination exemplified by acrylic resin, nylon, phenolic resin, urethane resin, and silica.

In this temperature history indicator, before heating, a granular or powdery heat-fusible substance and a granular or powdery pigment are in a mixed state, and the pigment is encapsulated in a microcapsule together with the heat-fusible substance. Things. When the indicator is heated above the melting point of the hot melt material, the hot melt material melts. The indicator changes sharply when the dye is diffused by dispersing or dissolving in the hot-melted substance or when the granular or powdered surface of the dye is wetted by the hot-melted substance. Cause

Since the diffusion is irreversible, this indicator does not return to the color tone before the color change even if the temperature decreases after the color change and the heat-fusible substance solidifies.

The heat-fusible substance and the pigment in the microcapsule may ooze out of the outer wall of the microcapsule and diffuse into the ink vehicle after the heat-fusible substance has been thermally melted.

When microcapsules are used, the stability of the heat-fusible substance or coloring matter in the ink is improved, and the environmental resistance is also improved. Further, it is not necessary to select a vehicle or a solvent for the vehicle in which the heat-fusible substance and the coloring matter are not dissolved at the time of forming the ink, so that printability and storage stability after printing are excellent.

The temperature history indicator is used by being placed near a product whose temperature history is to be detected or attached to the product. In addition, the temperature-sensitive ink may be directly printed on the product.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the temperature-sensitive ink of the present invention and a temperature history indicator using the same will be described in detail.

The temperature-sensitive ink includes microcapsules in which a granular or powdery heat-fusible substance and a pigment are encapsulated.

Specific examples of the heat-fusible substance include myristic acid, palmitic acid, adipic acid, octanoic acid, tricosanoic acid, tetratricontanic acid, 2,3-dimethylnonanoic acid, 23-methyltetracosanoic acid and 2-methyltetracosanoic acid. Hexenoic acid,
Brassic acid, 2-methyl-2-dodecenoic acid, β-eleostearic acid, behenolic acid, cis-9,10-methyleneoctadecanoic acid, scholmoog acid, 3,3 ′
-N-dodecyl thiodipropionate, trilaurin,
Palmitic acid anilide, stearic acid amide, zinc stearate, salicylic acid anilide, N-acetyl-L-glutamic acid, caproic acid-β-naphthylamide, enanthate phenylhydrazide, arachiic acid-p-chlorophenacyl, cholesteryl formate, 1-aceto- 2,3-distearin, n-pentadecyl thiolaurate, stearic acid chloride, palmitic anhydride, stearic acid-acetic anhydride, succinic acid, benzylammonium sebacate, 2-bromovaleric acid, α-sulfostearate methyl Fatty acid derivatives such as sodium salt and 2-fluoroarachinic acid; octadecyl alcohol, cholesterol,
D-mannitol, galactitol, heptatriacontanol, hexadecane-2-ol, 1-trans-
2-octadecenol, β-eleostearyl alcohol, cycloeicosanol, d (+) cellobiose,
p, p'-biphenol, riboflavin, 4-chloro-
Alcohol derivatives such as 2-methylphenol and 2-bromo-1-indanol; dihexadecyl ether, dioctadecyl ether, cytidine, adenosine;
Ether derivatives such as sodium phenoxyacetate, 1,3-bis (4-hydroxyphenoxy) benzene, aluminum triethoxide; stearaldehyde, paralauraldehyde, parastearinaldehyde, naphthaldehyde, p-chlorobenzaldehyde,
Aldehyde derivatives such as phthalaldehyde and 4-nitrobenzaldehyde; stearone, docosan-2-
Ketone derivatives such as on, phenylheptadecyl ketone, cyclononadecane, vinyl heptadecyl ketone, 4,4-bisdimethylaminobenzophenone, bis (2,4-pentanedionite) calcium and 1-chloroanthraquinone; tricosylamine, dioctadecyl Amine derivatives such as amine, N, N-dimethyloctylamine, heptadecamethyleneimine, naphthylamine, ethyl p-aminobenzoate, o-trithiourea, sulfamethazine, guanidine nitrate, p-chloroaniline, propylamine hydrochloride; hexyl Amide, octacosylamide, N-methyldodecylamide, N-methylheptacosylamide, α-cyanoacetamide, salicylamide, dicyandiamide, 2-nitrobenzamide,
Amide derivatives, such as N-bromoacetamide; nitrile derivatives, such as pentadecanenitrile, margaronitrile, 2-naphthonitrile, o-nitrophenoxyacetic acid, 3-bromobenzonitrile, 3-cyanpyridine, 4-cyanophenol; hexadecane , 1-Nonatria content, trans-n-2-octadecene,
Hexatriacontylbenzene, 2-methylnaphthalene, bicene, cyanuric chloride, 1-fluorononadecane,
1-chloroeicosane, 1-iodopentadecane, 1-
Hydrocarbon derivatives such as bromoheptadecane and 1,2,4,5-tetrakis (bromomethyl) benzene; pentadecanethiol, eicosanthiol, 2-naphthalenethiol, 2-mercaptoethyl ether and 2-nitrobenzenesulfenyl chloride; Thiol derivatives; 1,3-diatin, 2,11-dithia [3,
3] At least one of sulfide derivatives such as paracyclophane, bis (4-hydroxy-3-methylphenyl) sulfide, 4,4-dipyridyl sulfide, and 4-methylmercaptophenol is used.

The dyes are specifically CI Direct Orange 39, CI Direct Brown 2, CI Acid Yellow 73, CI Acid Red 52,
CI Acid Violet 49, CI Basic Yellow 11, CI Basic Red 38, Cation Red SGLH, Cation Red GTLH, Cation Red 4GH, Cation Red 7BNH (Hodogaya Chemical Co., Ltd.) C.I.), CI Mordant Red 7, C.I.
I. Mordant Black 38, C.I. Azoic Blue 9, C.I. Azoic Diazo Component 1
1, CI Sulfur Black 1, CI Sulfur Red 5, CI Bat Green 9, CI Bat Violet 2, CI Disperse Blue 3, Discharge Red BB (manufactured by Mitsui Toatsu Dye), C.I.
I. Reactive Blue 19, C.I.
Blue 15, Remazol Br Blue R-KN (manufactured by Mitsubishi), CI Solvent Orange 2, CI Solvent Blue 25, CI Acid Green 1, Flavianic Azido Disodium Salt And dyes such as primulin sulfonic acid; 4,10-dibromoanthanthrone, dibenzoanthrone, cochineal lake, CI Pigment Yellow 1, CI Pigment Red 38, and CI Pigment Blue. 15, C.I.
Pigment Red 209, CI Pigment Yellow 109, CI Pigment Green 10, CI Basic Red 1-Rake, CI Acid Red 87-Rake, CI Pigment・ Blue 6, CI Pigment Red 179, CI Pigment Red 8
8, Alizarin Lake, CI Pigment Violet 23, CI Pigment Green 8, CI Pigment Red 53, CI Pigment Yellow 23-
Lake, tannic acid / gallic acid / iron lake, CI Pigment Yellow 34, CI Pigment Yellow 35
And organic pigments; inorganic pigments such as kaolin, navy blue, strontium sulfate, titanium dioxide, aluminum hydroxide, calcium silicate, and carbon black. The CI is an abbreviation of a color index.

A temperature-sensitive ink is produced using the above-mentioned heat-fusible substance and a dye as follows. First, microcapsules are prepared by an interfacial polymerization method. That is, the high molecular compound forming the outer wall of the microcapsule is dissolved, but the hot-melt substance and the dye are not dissolved in the solvent, the hot-melt substance and the dye are mixed with a stirrer, disperser, homogenizer,
The mixture is dispersed and emulsified by stirring with a device such as a mixer.

Next, an emulsifying hardener and the like are added to form the outer walls of the microcapsules, and then the microcapsules and the solvent are separated by filtration or the like, to obtain microcapsules enclosing the heat-fusible substance and the dye. Can be

An ink vehicle and a solvent for the ink vehicle,
When the microcapsules are kneaded with a kneader, a temperature-sensitive ink is obtained. Printing the temperature sensitive ink on the substrate surface provides a temperature history indicator.

Hereinafter, examples of the temperature history indicators experimentally manufactured using the temperature-sensitive ink to which the present invention is applied are shown in Examples 1 to 7, and an example in which the present invention is experimentally manufactured using the ink not applied is shown in Comparative Example 1. Show.

Example 1 Microcapsules were prepared by an interfacial polymerization method. First, 99.9% of myristic acid as a heat-meltable substance and Acid Yellow 73 as a pigment.
Was mixed with 30 parts by weight of Epicoat 828 (trade name, manufactured by Yuka Shell Epoxy Co., Ltd.), which is an epoxy resin forming the outer wall of the microcapsule. This is added to a 2% sodium alkinate aqueous solution 500
In a dispersion medium in which 3 parts by weight of Euramine P-1500 (trade name, manufactured by Mitsui Toatsu Chemicals, Inc.), which is a urea resin, was dispersed and stirred for 20 minutes to emulsify.

Thereafter, 30 parts by weight of a curing agent Epicure (a product of Yuka Shell Epoxy Co., Ltd.) was added, and
The mixture was stirred for a time to form microcapsule walls. This liquid was filtered to obtain microcapsules enclosing the heat-fusible substance and the dye.

100 parts by weight of the microcapsules, 50 parts by weight of PAS800 medium as an ink vehicle, and butyl cellosolve 50 as a solvent for the ink vehicle.
When kneaded with a kneading machine, a temperature-sensitive ink was obtained. This ink was printed on the surface of plastic synthetic paper as a base material by screen printing to obtain a temperature history indicator.

(Examples 2 to 7, Comparative Example 1) The amounts of the polymer compound, the heat-fusible substance, and the dye shown in Table 1 were used, and Examples 2 and 4 were used in place of the interfacial polymerization method of Example 1. 7 to 7, microcapsules were prepared by a phase separation method, Example 3 by an in-liquid drying method, and Comparative Example 1 by an interfacial polymerization method as in Example 1. The subsequent preparation of the ink and trial production of the indicator were performed in the same manner as in Example 1 to obtain an indicator.

[0041]

[Table 1]

When the indicators manufactured in Examples 1 to 7 and Comparative Example 1 were placed in a thermostat and heated, the color change temperature at which a change in color tone was observed was examined. Table 1 shows the results.

As is clear from Table 1, the temperature history indicators of Examples 1 to 7 clearly changed color at a predetermined temperature.
It is possible to display that a predetermined temperature history has passed. Even when the temperature history indicator was stored after the discoloration, the color tone remained the same after the discoloration. On the other hand, in the indicator of Comparative Example 1, the blending amount of the microcapsules was too small.
Even when the hot-melt material was hot-melted, it was not colored and the original color tone was maintained.

[0044]

As described in detail above, the temperature-sensitive ink of the present invention can be used for printing regardless of its shape. Also, since mass production by printing is possible,
Significantly cheaper indicators can be manufactured. Further, by using heat-fusible substances having different melting points, various discoloration temperatures from a low temperature to a high temperature can be set.

The temperature history indicator obtained by printing this temperature-sensitive ink can be stored with the color tone after the color change because the color tone change is irreversible. Since microcapsules are used, the stability of the heat-fusible substance or dye in the ink and the environmental resistance are good. It is not necessary to select a vehicle or a solvent for the vehicle in which the heat-fusible substance and the coloring matter are not dissolved during the ink-forming, and the printing suitability and the storage stability after printing are excellent.

The temperature history indicator confirms that the product has been heated to a predetermined temperature or higher in the heating step of a product such as a processed food that requires temperature control, and a medical product, food, or electric component which should avoid heating. It is preferably used to confirm that the product has not been heated to a predetermined temperature during distribution or storage of the product.

If an ultraviolet curable resin is used as the ink vehicle, a temperature-sensitive ink having high environmental resistance can be obtained without covering with a laminate material. Further, as compared with an indicator covered with a laminate material, the number of manufacturing steps can be reduced, so that an inexpensive indicator with high productivity is provided.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Daisuke Harumoto 3-11-7 Izumicho, Sakado-shi, Saitama Parkside City 206 F-term (reference) 2H113 AA03 AA06 BA09 BB02 BB07 BB22 BC05 CA15 CA36 DA25 DA46 DA53 DA56 DA64 DA68 EA10 4J039 AB01 AB02 AB07 AB12 AD03 AD06 AD10 AE03 AE04 AE05 AE08 AE11 BB01 BC01 BC07 BC12 BC16 BC19 BC32 BC33 BC36 BC54 BD03 BE01 BE02 FA02 GA02 GA03 GA10

Claims (5)

[Claims] 1. A particulate or powdery heat-fusible substance having a melting point corresponding to the temperature to be recorded and a particulate or powdery pigment having a diffusive property due to dispersion or dissolution in the thermally melted substance. A thermosensitive ink characterized by containing microcapsules. 2. The outer wall of the microcapsule is formed of any one of polyvinyl alcohol, polystyrene, silicone resin, epoxy resin, acrylic resin, urea resin, gelatin, methyl cellulose, polyurethane, wax, gum arabic, dextrin, and nylon. The temperature-sensitive ink according to claim 1, wherein the temperature-sensitive ink is formed of a polymer compound. 3. The temperature-sensitive ink according to claim 1, wherein the microcapsules are contained in an amount of 10 to 70% by weight. 4. The heat-fusible substance is a fatty acid derivative,
At least one selected from an alcohol derivative, an ether derivative, an aldehyde derivative, a ketone derivative, an amine derivative, an amide derivative, a nitrile derivative, a hydrocarbon derivative, a thiol derivative, and a sulfide derivative, and the dye is a dye or a pigment. The temperature-sensitive ink according to claim 1, wherein: 5. A temperature history indicator, wherein the temperature-sensitive ink according to claim 1 is printed on a substrate.