JP2022129766A - Temperature sensor using temperature-sensitive chromogenic material and method for using the same - Google Patents

Abstract

To provide a temperature-sensitive chromogenic material that presents colors irreversibly in a low-temperature region, a temperature sensor using the material, and a method for using the sensor.SOLUTION: The temperature-sensitive chromogenic material includes: a first component (A) containing a leuco dye (a1) and a temperature adjusting agent (a2); and a second component (B) containing a solid adsorbent (b1). When the temperature of the first component (A) increases from a temperature lower than the melting point of the temperature adjusting agent (a2) to the melting point, the temperature adjusting agent (a2) melts, and the leuco dye (a1) reacts with the solid adsorbent (b1) and presents a color.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a thermochromic material that irreversibly develops color in a low temperature range, a temperature sensor using the same, and a method of using the same.

In the cold chain of foodstuffs, pharmaceuticals, etc., products go through various vendors before they reach consumers. However, since there is no unified temperature control system among traders, there is a possibility that the product may not be kept at an appropriate temperature when it is delivered or passed through a trader who does not have a temperature control system.

Efforts are being made to record the temperature history using electronic temperature sensors as a way to ensure that the correct temperature is being maintained. However, in this case the data must be stored in internal memory or communicated with an external network, and the electronic temperature sensor must be powered by batteries or an external power source. Such a power supply leads to increased management costs and vulnerability in the event of a disaster, and a management system that varies from vendor to vendor is highly uncertain and risky. Due to the recent rise in global environmental awareness, there is a demand for reduction of wasteful standby power and energy saving during operation, while the spread of e-commerce sites has increased demand for products that require temperature control, such as perishables and pharmaceuticals. Because of this, there is a demand for the development of a method of simply leaving a temperature history without supplying power.

Patent Document 1 discloses a substrate, a dye layer and a developer layer on the substrate, the dye layer containing a leuco dye and a first binder, the developer layer comprising the leuco A temperature indicator is described that includes a developer that develops a dye and a second binder, wherein the first and/or second binder is a hot-melt resin binder.

JP 2015-72208 A

However, in the temperature indicator described in Patent Document 1, it is necessary to use a material (paper, natural fiber, synthetic fiber, regenerated fiber, woven fabric, non-woven fabric, leather) that the molten liquid of the binder easily permeates as the base material. This is probably because the reaction between the leuco dye and the developer is generally inhibited by the presence of a liquid medium (liquid medium) that dissolves both substances. In other words, in order to cause the leuco dye and the color developer to react and develop the color of the leuco dye, it is necessary to remove the melt of the binder. it is conceivable that. In other words, the temperature indicator described in Patent Literature 1 cannot use a base material such as a resin film with low permeability, making it difficult to actually use it as an electronic temperature sensor.

Accordingly, an object of the present invention is to provide a thermochromic material that irreversibly develops color in a low temperature range, a temperature sensor using the same, and a method for using the same.

The thermochromic material according to the present invention comprises a first component (A) containing a leuco dye (a1) and a temperature control agent (a2), and a second component (B) containing a solid adsorbent (b1). and when the temperature of the first component (A) rises from a temperature lower than the melting point of the temperature adjusting agent (a2) to the melting point, the temperature adjusting agent (a2) melts and the leuco The dye (a1) reacts with the solid adsorbent (b1) to develop color.

The temperature sensor according to the present invention is a temperature sensor using the thermochromic material, wherein the layer of the first component (A) and the layer of the second component (B) are separated from each other by a release film is laminated through This temperature sensor can be used in a method comprising peeling off the release film and contacting the first component (A) layer and the second component (B) layer.

A temperature sensor according to the present invention is a temperature sensor using the thermochromic material described above, wherein the first component (A) is added to each region of the bag body divided into a plurality of regions by the weakly bonded portion. and the second component (B) are respectively introduced, and the weakly bonded portion is peeled off by increasing the pressure inside the bag body, and the region where the first component (A) is introduced and the first It can communicate with the area into which the second component (B) is introduced. By increasing the pressure inside the bag body, the temperature sensor peels off the weakly bonded portion, and the area where the first component (A) is introduced and the area where the second component (B) is introduced. It can be used by a method comprising the step of contacting the first component (A) and the second component (B) by communicating with the region.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a thermochromic material that irreversibly develops color in a low-temperature region, a temperature sensor using the same, and a method for using the same.

1 is a cross-sectional view showing the configuration of a temperature sensor according to one embodiment of the present invention; FIG. FIG. 2 is a cross-sectional view showing a state when using the temperature sensor of FIG. 1; BRIEF DESCRIPTION OF THE DRAWINGS It is a front view which shows the structure of the temperature sensor which concerns on one Embodiment of this invention, (a) shows the state before use, (b) the state at the time of start of use, (c) shows the state at the time of coloring.

The thermochromic material according to the present invention has a first component (A) and a second component (B). The first component (A) contains a leuco dye (a1) and a temperature control agent (a2). A second component (B) comprises a solid adsorbent (b1). Then, when the temperature of the first component (A) rises from a temperature lower than the melting point of the temperature control agent (a2) to the melting point, the temperature control agent (a2) melts and the leuco dye (a1) is solid-adsorbed. It reacts with the agent (b1) to irreversibly develop color. Therefore, the thermochromic material according to the present invention is a thermochromic material that irreversibly develops color at the melting point of the temperature adjusting agent (a2), and is used as a temperature sensor utilizing its characteristics.

The leuco dye (a1) is a dye that develops color by irreversibly changing its chemical structure through an oxidation-reduction reaction with a color developer, and itself is a colorless or light-colored dye precursor. The leuco dye (a1) includes one that acts as an electron donor and reacts with the color developer and one that acts as an electron acceptor and reacts with the developer. Those that react are preferred. Leuco dyes (a1) include triphenylmethanephthalide-based leuco compounds, triallylmethane-based leuco compounds, fluorane-based leuco compounds, phenothidian-based leuco compounds, thiofluorane-based leuco compounds, xanthene-based leuco compounds, indophthalyl-based leuco compounds, and spiropyran. leuco compound, azaphthalide leuco compound, chromenopyrazole leuco compound, methine leuco compound, rhodamine anilinolactam leuco compound, rhodamine lactam leuco compound, quinazoline leuco compound, diazaxanthene leuco compound, bislactone leuco compound compound and the like. Among them, triphenylmethanephthalide-based leuco compounds, fluoran-based leuco compounds, and azaphthalide-based leuco compounds are preferable. The leuco dye (a1) may be used alone or in combination of two or more.

［２］下記式（２）で表される３－シクロヘキシルアミノ－６－クロロフルオラン（ＣＡＳ：２６２０６－７８－０、発色時の色：橙）

［３］下記式（３）で表される３－（４－ジエチルアミノ－２－エトキシフェニル）－３－（１－エチル－２－メチルインドール－３－イル）－４－アザフタリド（ＣＡＳ：６９８９８－４０－４、発色時の色：青）

［４］下記式（４）で表される３－ジエチルアミノ－７－ジベンルアミノフルオラン（ＣＡＳ：３４３７２－７２－０、発色時の色：緑）

［５］下記式（５）で表される３－（Ｎ－シクロヘキル－Ｎ－メチルアミノ）－６－メチル－７－アニリノフルオラン（ＣＡＳ：５５２５０－８４－５、発色時の色：黒）

［６］下記式（６）で表される３－ジエチルアミノ－６，８－ジメチルフルオラン（ＣＡＳ：２１９３４－６８－９、発色時の色：橙）

［７］下記式（７）で表される６－（ジメチルアミノ）－３，３－ビス［ｐ－（ジメチルアミノ）フェニル］フタリド（ＣＡＳ：１５５２－４２－７、発色時の色：青紫）

Specific examples of the leuco dye (a1) include compounds [1] to [7] below.
[1] 3-diethylamino-7-chlorofluorane represented by the following formula (1) (CAS: 26567-23-7, color when developed: red)

[2] 3-cyclohexylamino-6-chlorofluorane represented by the following formula (2) (CAS: 26206-78-0, color when developed: orange)

[3] 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide (CAS: 69898-) represented by the following formula (3) 40-4, color when developing: blue)

[4] 3-diethylamino-7-dibenzylaminofluorane represented by the following formula (4) (CAS: 34372-72-0, color when developed: green)

[5] 3-(N-cyclohexyl-N-methylamino)-6-methyl-7-anilinofluorane represented by the following formula (5) (CAS: 55250-84-5, color when developed: black )

[6] 3-diethylamino-6,8-dimethylfluorane represented by the following formula (6) (CAS: 21934-68-9, color when developed: orange)

[7] 6-(dimethylamino)-3,3-bis[p-(dimethylamino)phenyl]phthalide represented by the following formula (7) (CAS: 1552-42-7, color when developed: bluish purple)

The temperature control agent (a2) is a substance having a melting point, and is solid at a temperature lower than the melting point, but melts and becomes liquid when the temperature rises to the melting point. The melted temperature control agent (a2) functions as a solvent for the leuco dye (a1), and the leuco dye (a1) migrates to the surface of the solid adsorbent (b1) to develop color. That is, since the melting point of the temperature control agent (a2) is the temperature at which the leuco dye (a1) develops color, a temperature control agent (a1) having a desired melting point may be selected depending on the purpose. The melting point of the temperature adjusting agent (a2) is not particularly limited, but is preferably −100° C. or higher, more preferably −70° C. or higher, further preferably −40° C. or higher, and −20 ° C. or higher is particularly preferable, and it may be -20 ° C. or higher, -10 ° C. or higher, 0 ° C. or higher, 10 ° C. or higher, or 20 ° C. or higher. The melting point of the temperature control agent (a2) may be 100° C. or lower, 80° C. or lower, 60° C. or lower, 50° C. or lower, 40° C. or lower, 30° C. or lower, or 20° C. or lower. good. Note that the melting point of the temperature control agent (a2) has a range, and in some cases melting actually starts at a temperature of about -2°C. The temperature adjusting agent (a2) may be used alone or in combination of two or more.

As the temperature regulator (a2), for example, an aliphatic alcohol can be used. The fatty alcohol may be a saturated fatty alcohol or an unsaturated fatty alcohol. The fatty alcohol may be linear or branched. The fatty alcohol may be a primary alcohol, a secondary alcohol, or a tertiary alcohol. Among them, linear saturated primary aliphatic alcohols are preferred. Specific examples of aliphatic alcohols include methyl alcohol (melting point: -97°C), ethyl alcohol (melting point: -114°C), 1-propyl alcohol (melting point: -126°C), 1-butyl alcohol (melting point: -90°C). °C), 1-pentyl alcohol (melting point: -78°C), 1-hexyl alcohol (melting point: -52°C), 1-heptyl alcohol (melting point: -35°C), 1-octyl alcohol (melting point: -16°C) , 1-nonyl alcohol (melting point: -7°C), 1-decyl alcohol (melting point: 6.4°C), 1-undecyl alcohol (melting point: 19°C), lauryl alcohol (melting point: 23.5°C), myristyl alcohol (melting point: 38° C.), cetyl alcohol (melting point: 49° C.), stearyl alcohol (melting point: 59.8° C.), arachidyl alcohol (melting point: 64° C.), and behenyl alcohol (melting point: 70° C.). Among them, linear saturated primary aliphatic alcohols having 6 to 22 carbon atoms are preferable, and linear saturated primary aliphatic alcohols having 8 to 18 carbon atoms are more preferable.

As the temperature regulator (a2), for example, a fatty acid alkyl ester can be used. The fatty acid alkyl ester may be a saturated fatty acid alkyl ester or an unsaturated fatty acid alkyl ester. The fatty acid alkyl ester may be linear or branched. Among these, linear saturated fatty acid alkyl esters are preferred. Specific examples of fatty acid alkyl esters include methyl formate (melting point: -100°C), ethyl formate (melting point: -81°C), isopropyl formate (melting point: -93°C), isopropyl formate (melting point: -96°C), and acetic acid. methyl (melting point: -98°C), ethyl acetate (melting point: -84°C), propyl acetate (melting point: -95°C), isopropyl acetate (melting point: -73°C), isopropyl propionate (melting point: -76°C), Isopropyl butyrate (melting point: -95°C), isopropyl valerate (melting point: -63°C), isopropyl caprylate (melting point: -46°C), methyl laurate (melting point: -7°C), ethyl laurate (melting point: -10°C) ℃), propyl laurate (melting point: 4°C), isopropyl laurate (melting point: 4°C), butyl laurate (melting point: -10°C), methyl myristate (melting point: 18°C), ethyl myristate (melting point: 18°C) 12°C), propyl myristate (melting point: -5°C), isopropyl myristate (melting point: 7°C), butyl myristate (melting point: 7°C), methyl palmitate (melting point: 32-35°C), ethyl palmitate (melting point: 24-26°C), propyl palmitate (melting point: 20°C), isopropyl palmitate (melting point: 13°C), butyl palmitate (melting point: 17°C), methyl stearate (melting point: 37-41°C) , ethyl stearate (melting point: 34-38° C.), propyl stearate (melting point: 29° C.), isopropyl stearate (melting point: 28° C.), butyl stearate (melting point: 17-22° C.). Among them, esters of linear saturated fatty acids having 10 to 20 carbon atoms (more preferably 12 to 18 carbon atoms) and alcohols having 1 to 4 carbon atoms (more preferably isopropyl alcohol) are preferred.

As the temperature adjusting agent (a2), in addition to the above, ketones such as acetone (melting point: -94°C), methyl ethyl ketone (melting point: -86°C), cyclohexanone (melting point: -16°C); diethyl ether (melting point: - 116°C), ethers such as tetrahydrofuran (melting point: -108°C); toluene (melting point: -95°C), o-xylene (melting point: -25°C), m-xylene (melting point: -48°C), p-xylene (melting point: 13° C.) and other aromatic hydrocarbons can be used. Considering that the thermochromic material containing the temperature adjusting agent (a2) is prepared at room temperature, the boiling point of the temperature adjusting agent (a2) is preferably 25° C. or higher, more preferably 30° C. or higher. is more preferable, and 40° C. or higher is even more preferable.

As the temperature adjuster (a2), it is preferable not to use a compound that acts as an acidic or basic substance on the leuco dye (a1) and/or the solid adsorbent (b1). That is, it is preferable to use a compound having neither an acidic group nor a basic group as the temperature adjusting agent (a2). In particular, when using a leuco dye (a1) that acts as an electron donor for the developer, if a basic compound (a compound having a basic group) is used as the temperature adjuster (a2), the leuco dye (a1 ) and the solid adsorbent (b1), the leuco dye (a1) may not develop color. , the leuco dye (a1) may develop color in the initial state. Basic compounds include amine compounds such as ethylenediamine. Acidic compounds include carboxylic acids, phenols, sulfonic acids, and phosphonic acids.

The content of the leuco dye (a1) in the first component (A) is preferably 0.1 to 5 parts by weight, preferably 0.3 to 3 parts by weight, relative to 100 parts by weight of the solid adsorbent (b1). parts by weight, more preferably 0.5 to 1.5 parts by weight.

The first component (A) includes, in addition to the leuco dye (a1) and the temperature adjuster (a2), a preservative, a thickener, a pH adjuster, an antirust agent, a lubricant, an antifoaming agent, an antiaging agent, Contains other ingredients such as antibacterial agents, flame retardants, ultraviolet absorbers, release agents, dispersants, antistatic agents, dyes other than leuco dyes (a1) (including fluorescent dyes), pigments, inorganic fine particles, organic fine particles, etc. You can stay. The content of other components in the first component (A) is preferably 10% by weight or less, more preferably 5% by weight or less, and even more preferably 2% by weight or less. Also, the first component (A) may be held on a holding substrate such as a woven fabric or non-woven fabric.

The solid adsorbent (b1) can adsorb the leuco dye (a1) and cause an oxidation-reduction reaction with the leuco dye (a1) to irreversibly change the chemical structure of the leuco dye (a1). It is possible. That is, the solid adsorbent (b1) functions as a developer. The solid adsorbent (b1) includes one that acts as an electron donor and reacts with the leuco dye (a1) and one that acts as an electron acceptor and reacts with the leuco dye (a1). Those that act and react are preferred.

As described above, the reaction between the leuco dye and the developer is generally inhibited by the presence of a liquid medium (liquid medium) that dissolves both substances. However, in the present invention, the leuco dye (a1) reacts while being adsorbed by the solid adsorbent (b1), so even if the liquid medium (melted temperature control agent (a2)) is present, the leuco dye The leuco dye (a1) develops color without inhibiting the reaction between (a1) and the developer (solid adsorbent (b1)).

The solid adsorbent (b1) may be organic, but preferably inorganic. Specific examples of the solid adsorbent (b1) include silica, alumina and zeolite. The solid adsorbent (b1) may be crystalline or amorphous (gel-like). Zeolite is preferred as the crystalline solid adsorbent (b1). As the amorphous (gel-like) solid adsorbent (b1), silica gel is preferable, and acidic or neutral silica gel is more preferable. In particular, when using a leuco dye (a1) that acts as an electron donor for a developer, if basic silica gel is used as the solid adsorbent (b1), the leuco dye (a1) may not develop color. The particle size and pore size of the solid adsorbent (b1) can be appropriately selected as long as the redox reaction can occur with the leuco dye (a1).

Regarding the amount of the solid adsorbent (b1), it may be an amount necessary for reacting with the leuco dye (a1) to develop color, and is 10 to 100 parts by weight with respect to 1 part by weight of the leuco dye (a1). is preferably 30 to 200 parts by weight, more preferably 50 to 150 parts by weight, and particularly preferably 70 to 100 parts by weight.

The second component (B) may consist only of the solid adsorbent (b1), but preferably further contains the temperature control agent (b2). As the temperature adjusting agent (b2), for example, the substances exemplified as the temperature adjusting agent (a2) described above can be used, but it is preferable to use the same substance as the temperature adjusting agent (a2) described above. By doing so, when the temperature adjusting agent (a2) of the first component (A) melts, the temperature adjusting agent (b2) of the second component (B) also melts at the same time, so that the first component (A) and the second component (B) are easily mixed, and the leuco dye (a1) is easily reacted with the solid adsorbent (b1).

The content of the solid adsorbent (b1) in the second component (B) is preferably 10% by weight or more, more preferably 20% by weight or more, and even more preferably 30% by weight or more. . The content of the solid adsorbent (b1) in the second component (B) may be 100% by weight, especially when the second component (B) contains the temperature control agent (b2), It may be 80% by weight or less, 60% by weight or less, or 45% by weight or less.

The second component (B) includes, in addition to the solid adsorbent (b1) and the temperature regulator (b2), a preservative, a thickener, a pH adjuster, an antirust agent, a lubricant, an antifoaming agent, and an antiaging agent. , Antibacterial agents, flame retardants, ultraviolet absorbers, release agents, dispersants, antistatic agents, dyes other than leuco dyes (a1) (including fluorescent dyes), pigments, inorganic fine particles, organic fine particles, etc. may contain. The content of other components in the second component (B) is preferably 10% by weight or less, more preferably 5% by weight or less, and even more preferably 2% by weight or less. Also, the first component (A) may be held on a holding substrate such as a woven fabric or non-woven fabric.

In the thermochromic material as described above, when the temperature of the first component (A) rises from a temperature lower than the melting point of the temperature adjusting agent (a2) to the melting point, the temperature adjusting agent (a2) melts. Then, the leuco dye (a1) reacts with the solid adsorbent (b1) to develop a color. That is, since it becomes a thermosensitive coloring material that develops color when the temperature rises to a predetermined temperature or higher and does not disappear even when the temperature returns to a temperature lower than the predetermined temperature, it can be suitably used as a temperature sensor for recording heat history during transportation and the like. . A temperature sensor according to the present invention and a method for using the same will be described below.

FIG. 1 shows the configuration of one embodiment of the temperature sensor according to the present invention. In the temperature sensor 1 shown in FIG. 1, a first component (A) layer 11 is formed on a first support 10, and a release film 12 is attached thereon. A layer 21 of the second component (B) is formed on the second support 20, and a release film 22 is attached thereon. Then, the release films 12 and 22 are arranged to face each other so that the layer 11 of the first component (A) and the layer 21 of the second component (B) overlap, and the first support 10 and the second The end portion 5 of the second support 20 is adhered by thermocompression bonding or the like. That is, in the temperature sensor 1 shown in FIG. 1, the layer 11 of the first component (A) and the layer 12 of the second component (B) are laminated with release films 12 and 22 interposed therebetween. With the temperature sensor 1 having such a configuration, the leuco dye will not develop color due to mixing of the first component (A) and the second component (B) before use.

Then, before starting use, first, the temperature is lowered to a temperature lower than the melting point of the temperature control agent (a2) as necessary to solidify the layer 11 of the first component (A). When the second component (B) contains the temperature control agent (b2), if necessary, the temperature is lowered to below the melting point of the temperature control agent (b2) to solidify the layer 11 of the second component (B). . Here, as shown in FIGS. 1 and 2, for example, a leuco dye (a1), a temperature control agent (a2) and a general It is preferable to form a solidification confirming portion 6 into which a mixture containing a color developer is added. That is, when the mixture containing these three substances is solid below the melting point of the temperature control agent (a2), the leuco dye (a1) develops color, and when it is liquid above the melting point of the temperature control agent (a2), the leuco dye ( Since a1) is decolored, it is confirmed that the temperature control agent (a2) has solidified due to the color development of the leuco dye (a1) in the solidification confirmation portion 6 (=the layer 11 of the first component (A) has solidified). can do. As a general color developer, for example, alkoxyphenol, hydroxybenzoic acid alkyl ester, or derivatives thereof can be used.

Then, at the start of use, as shown in FIG. 2, the release films 12 and 22 are peeled off, and the layer 11 of the first component (A) and the layer 12 of the second component (B) are laminated so as to overlap each other. bring them into contact. At this time, it is preferable to adhere the periphery of the first support 10 and the second support 20 to seal the layer 11 of the first component (A) and the layer 12 of the second component (B). By doing so, when the temperature of the first component (A) rises to the melting point of the temperature control agent (a2), the temperature control agent (a2) melts, and the leuco dye (a1) turns into the solid adsorbent (b1 ) can be adsorbed and reacted to develop a color.

The first support 10 and the second support 20 may support the layer 11 of the first component (A) and the layer 12 of the second component (B), respectively. For example, polyolefin films such as PE films and PP films; polyamide films such as Ny films; and resin film supports such as polyester films such as PET films can be used. At the start of use, the periphery of the first support 10 and the second support 20 is adhered to seal the layer 11 of the first component (A) and the layer 12 of the second component (B). It is preferred to use a film support with an agent. The release films 12 and 22 may be those that can be attached to the layer 11 of the first component (A) and the layer 12 of the second component (B), respectively, and can be peeled off as necessary.

FIG. 2 shows the configuration of another embodiment of the temperature sensor according to the present invention. In the temperature sensor 1 shown in FIG. 2( a ), each region of the bag body 30 divided into a plurality (top and bottom in FIG. 2) by the weakly bonded portion 36 (in FIG. 50), the first component (A) 41 and the second component (B) 51 are put in, respectively, and the ends are adhered by the strong adhesion part 35 . With the temperature sensor 1 having such a configuration, the leuco dye will not develop color due to mixing of the first component (A) and the second component (B) before use.

Before the start of use, the first component (A) 41 is solidified by lowering the temperature below the melting point of the temperature control agent (a2), if necessary. When the second component (B) contains the temperature control agent (b2), the second component (B) 51 is solidified by lowering the temperature below the melting point of the temperature control agent (b2) as necessary. Here, in the same manner as described above, for example, a mixture containing a leuco dye (a1), a temperature control agent (a2), and a general color developer is applied to the side portion of the bag 30 or the position to be the strong adhesion portion 35. By forming a solidification confirmation part (not shown) that has been put in, the temperature control agent (a2) solidifies due to the color development of the leuco dye (a1) in the solidification confirmation part (= the first component (A) 41 solidifies can be confirmed). Then, at the start of use, as shown in FIG. 2B, by increasing the pressure inside the bag 30, the weakly bonded portion 36 is peeled off, and the region where the first component (A) 41 has been introduced is removed. The first component (A) 41 and the second component (B) 51 are brought into contact by communicating with the region into which the second component (B) 51 is introduced. By doing so, when the temperature of the first component (A) rises to the melting point of the temperature control agent (a2), the temperature control agent (a2) melts to form leuco as shown in FIG. 2(c). The dye (a1) is adsorbed by the solid adsorbent (b1) and reacts to develop color.

The temperature sensor according to the present invention as described above develops a color when the temperature reaches a predetermined temperature (the melting point of the temperature adjusting agent (a2)) or higher, and the color does not disappear even when the temperature returns to a temperature lower than the predetermined temperature. History can be recorded. In particular, detection of temperature rises during transport of pharmaceuticals and perishables, identification of abnormal heat generating parts such as electrical appliances and batteries, inspection of plants, labels and tags that can be printed at low temperatures, simple thermosensors that allow easy visual confirmation of heat generation, It is suitable for temperature-sensitive markers when using a near/far infrared laser.

<Example 1>
1 mg of 3-diethylamino-7-chlorofluorane (compound of formula (1) above) as a leuco dye (a1) and 100 mg of lauryl alcohol (melting point: 23.5° C.) as a temperature control agent (a2) The mixture was mixed and heated with stirring at 80° C. for 1 hour to obtain a uniform liquid mixture to be the first component (A). A 20 x 20 mm non-woven fabric as a holding substrate is attached to the center position of a 50 x 50 mm PET base film (with paste) as the first support, and the first component (A) is applied from above. A mixed liquid was added dropwise. Further, a release film was attached thereon to obtain a laminate (i) in which the layer of the first component (A) (+ the holding substrate) was sandwiched and sealed between the base film and the release film.

On the other hand, 80 mg of acidic silica gel (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name: Wakogel C-300) as a solid adsorbent (b1) and 120 mg of lauryl alcohol as a temperature control agent (b2) were mixed and heated at 80 ° C. By kneading under heating, a mixture to be the second component (B) was obtained. A mixture to be the second component (B) was applied to the central position of a 50×50 mm 50×50 mm PET base film (with adhesive) as a second support. Further, a release film was attached thereon to obtain a laminate (ii) in which the layer of the second component (B) was sandwiched and sealed between the base film and the release film.

Laminate (i) and laminate (ii) obtained above are placed so that the release film sides face each other so that the layers of the first component (A) and the layers of the second component (B) overlap. The temperature sensor having the structure shown in FIG. 1 was obtained by arranging and thermocompression bonding the ends of the base films of the laminate (i) and the laminate (ii).

In order to solidify the temperature regulating agent in the obtained temperature sensor, it is left in a freezer set at −20° C. for 10 minutes, and the layer of the second component (B) changes from translucent (liquid) to white (solid). I confirmed that it is. After that, the release films of the laminate (i) and the laminate (ii) were peeled off in an environment of 20°C or less, and the layers of the first component (A) and the layer of the second component (B) were attached so that they overlapped. Together, the structure shown in FIG. 2 was adopted.

This temperature sensor was allowed to stand for 10 minutes in a constant temperature bath set at a melting point of 23.5° C. of lauryl alcohol as a temperature adjusting agent, and the presence or absence of color development was confirmed. Regarding the determination of color development, a color difference meter (manufactured by TES, trade name: TES135A Color Meter) was used, and when the lightness difference ΔL ^* was 10 or more based on the hue before color development, the color development was judged to be "present", and 10 or less. When it was, it was set as color development "absence". Further, the color-developed temperature sensor was again placed in a freezer set at -20°C for 10 minutes, and the state of color development was confirmed. The results are shown in Tables 1-3.

<Example 2>
The procedure was carried out in the same manner as in Example 1, except that 3-cyclohexylamino-6-chlorofluorane (the compound of formula (2) above) was used as the leuco dye (a1). Table 1 shows the results.

<Example 3>
As the leuco dye (a1), 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide (compound of formula (3) above) was carried out in the same manner as in Example 1, except that Table 1 shows the results.

<Example 4>
The procedure was carried out in the same manner as in Example 1, except that 3-diethylamino-7-dibenzylaminofluorane (the compound of formula (4) above) was used as the leuco dye (a1). Table 1 shows the results.

<Example 5>
The procedure was carried out in the same manner as in Example 1, except that myristyl alcohol (melting point: 38° C.) was used as the temperature adjuster (a2) and the temperature adjuster (b2). Table 2 shows the results.

<Example 6>
The procedure was carried out in the same manner as in Example 1, except that cetyl alcohol (melting point: 49°C) was used as the temperature adjuster (a2) and the temperature adjuster (b2). Table 2 shows the results.

<Example 7>
The procedure was carried out in the same manner as in Example 1, except that isopropyl myristate (melting point: 7°C) was used as the temperature adjuster (a2) and the temperature adjuster (b2). Table 2 shows the results.

<Example 8>
The procedure was carried out in the same manner as in Example 1, except that isopropyl palmitate (melting point: 13° C.) was used as the temperature adjuster (a2) and the temperature adjuster (b2). Table 2 shows the results.

<Comparative Example 1>
The procedure was carried out in the same manner as in Example 1, except that ethylenediamine (melting point: 10°C) was used as the temperature adjuster (a2) and the temperature adjuster (b2). Table 2 shows the results.

<Example 9>
It was carried out in the same manner as in Example 1, except that neutral silica gel (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name: Wakogel HC-N) was used as the solid adsorbent (b1). Table 3 shows the results.

<Comparative Example 2>
It was carried out in the same manner as in Example 1, except that basic silica gel (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name: Wakogel 50NH) was used as the solid adsorbent (b1). Table 3 shows the results.

<Example 10>
As the solid adsorbent (b1), it was carried out in the same manner as in Example 1, except that natural zeolite (manufactured by SHINSEI, trade name: No. 1) was used. Table 3 shows the results.

<Example 11>
It was carried out in the same manner as in Example 1, except that synthetic zeolite (manufactured by Tosoh, trade name: HSZ-600) was used as the solid adsorbent (b1). Table 3 shows the results.

As described above, it was found that the thermochromic material according to the present invention irreversibly develops color at the melting point of the temperature control agent used. Further, the temperature at which the color develops can be changed depending on the type of the temperature control agent used, and the color developed can be changed depending on the type of the leuco dye used.

1 temperature sensor 5 end 6 solidification confirmation part 10 first support 11 first component (A) layer 12 release film 20 second support 21 second component (B) layer 22 release film 30 bag body 35 strongly bonded portion 36 weakly bonded portion 40 first region 41 first component (A)
50 second region 51 second component (B)

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a temperature sensor using a thermochromic material that irreversibly develops color in a low temperature range, and a method for using the same.

The temperature sensor according to the present invention has a first component (A) containing a leuco dye (a1) and a temperature regulator (a2), and a second component (B) containing a solid adsorbent (b1). Then, when the temperature of the first component (A) rises from a temperature lower than the melting point of the temperature adjusting agent (a2) to the melting point, the temperature adjusting agent (a2) melts and the leuco dye (a1 ) is a temperature sensor using a thermochromic material that develops color by reacting with the solid adsorbent (b1),
further comprising a solidification confirmation unit into which a mixture containing the leuco dye (a1), the temperature regulator (a2), and a developer is introduced;
At a temperature equal to or higher than the melting point of the temperature control agent (a2), the leuco dye (a1) is decolorized, and at a temperature lower than the melting point of the temperature control agent (a2), the leuco dye (a1) becomes visible. It reacts with coloring agents to develop color .

In the temperature sensor according to the present invention, for example, a layer of the first component (A) and a layer of the second component (B) are laminated via a release film. This temperature sensor can be used in a method comprising peeling off the release film and contacting the first component (A) layer and the second component (B) layer.

In the temperature sensor according to the present invention, for example, the first component (A) and the second component (B) are put into each region of the bag body divided into a plurality of regions by weakly bonded parts. The weakly bonded portion is peeled off by increasing the pressure inside the bag, and the region into which the first component (A) is introduced and the region into which the second component (B) is introduced are communicated. can be made By increasing the pressure inside the bag body, the temperature sensor peels off the weakly bonded portion, and the area where the first component (A) is introduced and the area where the second component (B) is introduced. It can be used by a method comprising the step of contacting the first component (A) and the second component (B) by communicating with the region.

ADVANTAGE OF THE INVENTION According to this invention, the temperature sensor using the thermochromic material which irreversibly develops a color in a low-temperature range, and its usage method can be provided.

Claims (14)

a first component (A) containing a leuco dye (a1) and a temperature control agent (a2);
and a second component (B) containing a solid adsorbent (b1),
When the temperature of the first component (A) rises from a temperature lower than the melting point of the temperature adjusting agent (a2) to the melting point, the temperature adjusting agent (a2) melts and the leuco dye (a1) A thermochromic material that reacts with the solid adsorbent (b1) to develop a color. The leuco dye (a1) is
3-diethylamino-7-chlorofluorane represented by the following formula (1):

3-cyclohexylamino-6-chlorofluorane represented by the following formula (2):

3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide represented by the following formula (3):

3-diethylamino-7-dibenzylaminofluorane represented by the following formula (4):

3-(N-cyclohexyl-N-methylamino)-6-methyl-7-anilinofluorane represented by the following formula (5):

3-diethylamino-6,8-dimethylfurane represented by the following formula (6):

Or 6-(dimethylamino)-3,3-bis[p-(dimethylamino)phenyl]phthalide represented by the following formula (7):

The thermochromic material according to claim 1, wherein 3. The thermochromic material according to claim 1, wherein the temperature adjusting agent (a2) is a fatty alcohol or a fatty acid alkyl ester. The thermochromic material according to any one of claims 1 to 3, wherein the temperature adjusting agent (a2) has a melting point of -20 to 60°C. The thermochromic material according to any one of claims 1 to 4, wherein the solid adsorbent (b1) is acidic or neutral silica gel or zeolite. The thermochromic material according to any one of claims 1 to 5, wherein the second component (B) further contains a temperature adjusting agent (b2). 7. The thermochromic material according to claim 6, wherein the temperature adjusting agent (b2) is the same substance as the temperature adjusting agent (a2). A temperature sensor using the thermochromic material according to any one of claims 1 to 7,
A temperature sensor in which a layer of the first component (A) and a layer of the second component (B) are laminated via a release film. A layer of the first component (A) is formed on a first support,
9. The temperature sensor according to claim 8, wherein a layer of said second component (B) is formed on a second support. further comprising a solidification confirmation unit into which a mixture containing the leuco dye (a1), the temperature regulator (a2), and a developer is introduced;
At a temperature equal to or higher than the melting point of the temperature control agent (a2), the leuco dye (a1) is decolorized, and at a temperature lower than the melting point of the temperature control agent (a2), the leuco dye (a1) becomes visible. 10. The temperature sensor according to claim 8 or 9, which reacts with a colorant to develop a color. A method of using a temperature sensor according to any one of claims 8 to 10,
a step of peeling off the release film;
contacting the layer of said first component (A) and said layer of second component (B). A temperature sensor using the thermochromic material according to any one of claims 1 to 7,
The first component (A) and the second component (B) are put into each region of the bag divided into a plurality of regions by the weakly bonded portion,
The weakly bonded portion is peeled off by increasing the pressure inside the bag, and the region into which the first component (A) is introduced and the region into which the second component (B) is introduced are communicated. A temperature sensor that can further comprising a solidification confirmation unit into which a mixture containing the leuco dye (a1), the temperature regulator (a2), and a developer is introduced;
At a temperature equal to or higher than the melting point of the temperature control agent (a2), the leuco dye (a1) is decolorized, and at a temperature lower than the melting point of the temperature control agent (a2), the leuco dye (a1) becomes visible. 13. The temperature sensor according to claim 12, which reacts with a colorant to develop color. 14. A method of using a temperature sensor according to claim 12 or 13,
By increasing the pressure inside the bag body, the weakly bonded portion is peeled off, and the region where the first component (A) is introduced and the region where the second component (B) is introduced are communicated. A method of using a temperature sensor, comprising the step of bringing said first component (A) and said second component (B) into contact by bringing them into contact.

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