JP6863402B2 - Temperature detection film and its manufacturing method - Google Patents

Description

The present invention relates to a temperature detection film and a method for producing the same.

Foods that require low-temperature and frozen storage, such as fresh foods and frozen foods, and cold-preserved medicines, such as vaccines and biopharmacy, require a cold chain that keeps them at a low temperature without interruption during the distribution process of production, transportation, and consumption. In general, in order to constantly measure and record the temperature at the time of distribution, a data logger capable of continuously recording time and temperature is often installed in a shipping container. This makes it possible to clarify the responsibility for any damage to the product.

When controlling the quality of individual products, temperature indicators (temperature detection labels) may be used instead of expensive data loggers. The temperature detection label has a layer containing a temperature detection material that stains when the temperature exceeds or falls below a preset temperature. That is, since the surface of the temperature detection label is dyed when the temperature exceeds or falls below the preset temperature, it is possible to know the change in the temperature environment. Although the temperature detection label is not as accurate as the data logger, it can be attached to each product individually, and has the advantage that it can be operated at a lower cost than the data logger.

In particular, when managing products such as fresh foods and biopharmaceuticals whose quality deteriorates depending on the temperature and time, the time-temperature indicator (Time-) that changes color by integrating time and temperature as a temperature detection label Temperature Indicator (TTI) is used.

A technique relating to such a temperature detection label is described in, for example, Patent Document 1. The patent document 1 includes a first material including a first temperature indicating material, a temperature detecting material including a second temperature indicating material, and a substrate, and the temperature detecting material is provided on the substrate. The temperature detection label on which the above is arranged is described.
Then, in this Patent Document 1, it is provided between the base material, the temperature detection material arranged on the base material, the transparent base material arranged on the temperature detection material, and the base material and the transparent base material. In addition, a temperature detection label provided with a spacer for sandwiching the temperature detection material from the horizontal direction is exemplified.

Japanese Unexamined Patent Publication No. 2018-179826

However, the temperature detection label described in Patent Document 1 uses a plurality of members such as a base material, a temperature detection material, a transparent base material, and a spacer, so that the cost is high. Therefore, there has been a request for a lower cost for the temperature detection label.
Further, when the temperature detection label described in Patent Document 1 is used as TTI, for example, it is necessary to achieve both the color development temperature and the color development time, but the dispersibility in the temperature detection material depends on the combination of the temperature indicating material and the matrix material. Therefore, the color development time (temperature detection time) may be significantly affected. In particular, when the temperature detection label described in Patent Document 1 is used as TTI, it is expected that it will be used for a long time, so there has been a request for a longer temperature detection time.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a temperature detection film having a low cost and a long temperature detection time, and a method for producing the same.

The temperature detection film according to the present invention that solves the above problems includes a matrix material and a temperature indicating material dispersed in the matrix material. The matrix material is a polyolefin-based polymer, and the temperature indicating material is a polyolefin-based polymer. , Leuco dye, color developer, and decolorizing agent, and the relationship between the melting point A of the temperature indicator or the decoloring agent and the melting point B of the matrix material is melting point B-melting point A> 30 ° C. The content of the matrix material was 50% by mass or more, and the melt flow rate was 0.5 g / 10 min or more and 10 g / 10 min or less.

According to the present invention, it is possible to provide a temperature detection film having a low cost and a long temperature detection time and a method for producing the same.
Issues, configurations and effects other than those described above will be clarified by the description of the following embodiments.

It is a schematic diagram which showed the change of the color density by the temperature of the temperature indicator material which can contain the temperature detection material used for the temperature detection film which concerns on one Embodiment of this invention. It is a schematic diagram which showed the change of the color density by the temperature of the temperature indicator material which can contain the temperature detection material used for the temperature detection film which concerns on one Embodiment of this invention. It is a schematic diagram which showed the change of the color density of the temperature detection material which can be suitably used for the temperature detection film which concerns on one Embodiment of this invention. It is a schematic diagram of the phase separation structure of the temperature detection film which concerns on one Embodiment of this invention, and shows the state which the temperature indicator material is developing color. It is an enlarged view of the ivb part in FIG. 4A. It is a schematic diagram of the phase separation structure of the temperature detection film which concerns on one Embodiment of this invention, and shows the state in which the temperature indicator material is decolorized. It is an enlarged view of the ivd part in FIG. 4C. It is a flowchart explaining the content of the manufacturing method of the temperature detection film which concerns on one Embodiment of this invention. It is a photograph of the temperature detection film according to Example 1 taken from above in a state (initial state) before color development immediately after production (stored at room temperature for 0 hours). In the figure, the scale bar at the lower right represents 10 mm. It is a photograph of the temperature detection film according to Example 1 taken from above in a state of being stored at room temperature for 5 days (stored for about 120 hours) and developed in color. In the figure, the scale bar at the lower right represents 10 mm. It is a photograph taken from the side about the temperature detection film which concerns on Example 1 shown in FIG. 6B. In the figure, the scale bar at the lower right represents 10 mm. The thickness of the temperature detection film according to the first embodiment is 400 μm (t = 400 μm).

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Since the drawings referred to in the following description schematically show the embodiment, the scale, spacing, positional relationship, etc. of the members are exaggerated or deformed, or a part of the members is not shown. There may be. It should be noted that the following description shows specific examples of the contents of the present invention, and the present invention is not limited to these descriptions, and is by those skilled in the art within the scope of the technical idea disclosed in the present specification. Various changes and modifications are possible. Further, in all the drawings for explaining the present invention, those having the same function may be designated by the same reference numerals, and the repeated description thereof may be omitted.
The term "~" described in the present specification is used to mean that the numerical values described before and after it are used as the lower limit value and the upper limit value. In the numerical range described stepwise in this specification, the lower limit or upper limit described in one numerical range may be replaced with the lower limit or upper limit described in another stepwise. It may be replaced with the numerical value shown in the Example.
In the present specification, the temperature detection film will be described as an example, but the technical idea of the present invention can also be applied to a time-temperature indicator (Time Temperature Indicator; TTI) and the like.

First, a temperature detection material that can be suitably used for the temperature detection film according to the embodiment of the present invention will be described, and then the structure of the temperature detection film and the manufacturing method thereof will be described.

<Temperature detection material>
The temperature detection film according to the embodiment of the present invention is formed by molding a temperature detection material containing a matrix material and a temperature indicating material dispersed in the matrix material into a predetermined shape as described in the item of manufacturing method. It is preferably produced by the above.

In the drawings to be referred to, FIGS. 1 and 2 are schematic views showing changes in color density depending on the temperature of the temperature indicating material that can be contained in the temperature detecting material used in the temperature detecting film according to the embodiment of the present invention, respectively. FIG. 3 is a schematic view showing a change in color density of a temperature detection material that can be suitably used for the temperature detection film according to the embodiment of the present invention.

As shown in FIG. 1 or 2, the temperature detection material preferably used in the present embodiment is at least one of the temperature indicating materials having different hysteresis characteristics of the color density-temperature curve, preferably FIG. It contains two as shown. The temperature detection material that can be suitably used in the present embodiment can be obtained by solidifying the temperature indicating material using a matrix material.

(Temperature indicator)
As the temperature indicating material, a material whose color density changes reversibly due to a temperature change (increasing / decreasing temperature) is used. The temperature indicator includes a leuco dye which is an electron donating compound, a color developer which is an electron accepting compound, and a decolorizing agent for controlling a temperature range of discoloration.

The temperature indicating material will be described in more detail with reference to FIGS. 1 to 3. In FIGS. 1 to 3, T indicates temperature, a indicates color development, d indicates decolorization, and 1 and 2 indicate first temperature indicating material and second temperature indicating material, respectively. Therefore, for example, "Ta1" indicates the color developing temperature of the first temperature indicating material, and "Td1" indicates the decolorizing temperature of the first temperature indicating material. Further, in FIGS. 1 to 3, the horizontal axis represents the temperature and the vertical axis represents the color density. Both temperature and color density increase as the distance from the origin increases in the direction of the arrow.

The first temperature indicating material has the hysteresis characteristic of the color density change shown in FIG. The first temperature indicating material maintains the decolorized state up to the developing temperature Ta1 as the temperature decreases from the state of P1 which is a molten state of the decoloring temperature Td1 or higher. When the color development temperature is Ta1 or less, the decoloring agent becomes a crystalline state below the freezing point, and the leuco dye and the color developer are separated, so that the leuco dye and the color developer combine to develop color.

The second temperature indicating material has the hysteresis characteristic of the color density change shown in FIG. If a material that is difficult to crystallize is used as the decoloring agent for the second temperature indicating material, the decolorizing agent will be used when the second temperature indicating material is rapidly cooled from P1 which is in a molten state of the decoloring temperature Td2 or more to the developing color temperature Ta2 or less. It is possible to form an amorphous state and maintain the decolorized state while incorporating the color developer. From this state, when the temperature is raised to a developing temperature of Ta2 or higher (above the crystallization start temperature near the glass transition point) in the heating process, the decolorizing agent crystallizes and develops color.

An object of the present embodiment is to guarantee the temperature control of an article such as a product at the time of distribution. When a temperature detection material that changes color reversibly due to a temperature change is used, the temperature rises or falls once during distribution, and even if the color of the temperature detection material changes, if the temperature drops or rises again during the distribution process. The color returns to its original state, and it is not possible to know whether or not there is a change in temperature. However, if the material showing the discoloration phenomenon of FIGS. 1 and 2 is used as the temperature indicating material, the change in the temperature environment can be known because the color does not easily return. FIG. 3 illustrates the hysteresis characteristics of the color density-temperature curve when the first temperature indicating material and the second temperature indicating material are mixed with one temperature detecting material. In the example shown in FIG. 3, Ta2 is the color development temperature of the second temperature indicating material and the detection temperature of the deviation from the upper limit temperature of the article. Further, Ta1 indicates the color development temperature of the first temperature indicating material and the detection temperature of the deviation from the lower limit temperature of the article. The shaded area in FIG. 3 is the control temperature range of the article.

That is, in the example shown in FIG. 3, the temperature detecting material is in a supercooled state, remains in a liquid state even in a state below the melting point, and is in a decolorized state, that is, the first temperature indicating material is used for lower limit detection. I am using it. Further, in the example shown in FIG. 3, the temperature indicating material is rapidly cooled from a molten state equal to or higher than the melting point of the temperature indicating material, the temperature indicating material forms an amorphous state, and a decolorized state, that is, the second temperature indicating material is used for upper limit detection. ing. The temperature detecting material in the present embodiment can suitably detect the presence or absence of a change in the temperature environment by adjusting the discoloration width of these two types of temperature indicating materials. Further, the temperature detecting material in the present embodiment can detect both a temperature rise and a temperature fall by the combination of the two types of temperature indicating materials. Further, in the temperature detection material of the present embodiment, the discolored state once developed can be returned to the initial decolorized state by raising the temperature of each temperature indicating material to a temperature equal to or higher than the melting point. Therefore, the temperature detection material in the present embodiment shows irreversibility at a temperature below the melting point of the two types of temperature indicating materials, can detect temperature deviations at the upper and lower limits, and controls the temperature after the temperature rises to the temperature above the melting point. By quenching to, it becomes a combination that can initialize the function.

The content of the temperature-indicating material in the temperature-detecting material can be arbitrarily set within the range in which it can function as the temperature-detecting material (that is, in the range in which the color development and decolorization of the temperature-indicating material can be confirmed), and is not particularly limited. The content of the temperature indicating material in the temperature detecting material is preferably less than 50% by mass, for example, when the temperature detecting material is 100% by mass, from the viewpoint of visibility. The content of the temperature indicating material in the temperature detecting material can be arbitrarily set within this range in consideration of visibility, cost and the like.

(Leuco dye)
Leuco dyes are electron-donating compounds that can be colored by a developer. As the leuco dye, known dyes conventionally used as dyes for pressure-sensitive copying paper and dyes for thermal recording paper can be used. Examples of leuco dyes include triphenylmethanephthalide, fluorane, phenothiazine, indolylphthalide, leucooramine, spiropirane, rhodamine lactam, triphenylmethane, triazene, and spiroftalanthene. A system, a naphtholactam system, an azomethine system, or the like can be used. Specific examples of leuco dyes include 9- (N-ethyl-N-isopentylamino) spiro [benzo [a] xanthene-12,3'-phthalide] and 2-methyl-6- (Np-tolyl-). N-ethylamino) -fluorane, 6- (diethylamino) -2-[(3-trifluoromethyl) anilino] xanthene-9-spiro-3'-phthalide, 3,3-bis (p-diethylaminophenyl) -6 -Dimethylaminophthalide, 2'-anilino-6'-(dibutylamino) -3'-methylspiro [phthalide-3,9'-xanthene], 3- (4-diethylamino-2-methylphenyl) -3-( 1-Ethyl-2-methylindole-3-yl) -4-azaphthalide, 1-ethyl-8- [N-ethyl-N- (4-methylphenyl) amino] -2,2,4-trimethyl-1, Examples thereof include 2-dihydrospiro [11H-chromeno [2,3-g] quinoline-11,3'-phthalide].
As the leuco dye of the temperature indicating material in the present embodiment, only one type of these leuco dyes may be used, or two or more types may be used in combination. In the present embodiment, a leuco dye suitable for the temperature indicating material can be appropriately selected according to the required temperature (when the first temperature indicating material and the second temperature indicating material are used, the leuco dye suitable for each can be appropriately selected). When the first temperature indicating material and the second temperature indicating material are used, the leuco dye described above can be commonly used for both the first temperature indicating material and the second temperature indicating material.

(Color developer)
The color developer changes the structure of the leuco dye and causes color development by contacting with the electron-donating leuco dye. As the color developer, known ones conventionally used for thermal recording paper, pressure-sensitive copying paper, and the like can be used. Specific examples of such a developer include benzyl 4-hydroxybenzoate, 2,2'-biphenol, 1,1-bis (3-cyclohexyl-4-hydroxyphenyl) cyclohexane, and 2,2-bis (3). -Cyclohexyl-4-hydroxyphenyl) propane, bisphenol A, bisphenol F, bis (4-hydroxyphenyl) sulfide, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxy-3-3) Examples thereof include phenols such as methylphenyl) cyclohexane, α, α, α'-tris (4-hydroxyphenyl) -1-ethyl-4-isopropylbenzene, paraoxybenzoic acid ester, and gallic acid ester. The color developer is not limited to these, and may be any compound that is an electron acceptor and can change the color of the leuco dye. The color-developing agent includes metal salts of carboxylic acid derivatives, salicylic acid and salicylic acid metal salts, sulfonic acids, sulfonates, phosphoric acids, phosphoric acid metal salts, acidic phosphoric acid esters, acidic phosphoric acid ester metal salts, and phosphite. Acids, metal phosphite salts and the like may be used. In particular, the color developer preferably has high compatibility with leuco dyes and decoloring agents described later, and is an organic color developer such as benzyl 4-hydroxybenzoate, 2,2'-bisphenol, bisphenol A, and gallic acid esters. Coloring agents are preferred.

As the color developer of the temperature indicating material in the present embodiment, only one type of these color developer may be used, or two or more types may be used in combination. By combining a color developer, the color density of the leuco dye at the time of coloration can be adjusted more precisely. In the present embodiment, a color developer suitable for the temperature indicator can be appropriately selected according to the required temperature (when the first temperature indicator and the second temperature indicator are used, a color developer suitable for each can be appropriately selected. ). When the first temperature indicating material and the second temperature indicating material are used, the above-mentioned color developer can be commonly used for both the first temperature indicating material and the second temperature indicating material. The amount of the color developer used is selected according to the desired color density. The amount of the developer to be used may be selected, for example, in the range of about 0.1 part by mass to 100 parts by mass with respect to 1 part by mass of the leuco dye described above.

(Decolorizing agent)
The decoloring agent is a compound capable of dissociating the bond between the leuco dye and the color developer, and is a compound capable of controlling the color development temperature of the leuco dye and the color developer. Generally, in the temperature range in which the leuco dye is colored, the decolorizing agent is solidified in a phase-separated state. Further, in the temperature range in which the leuco dye is in the decolorizing state, the decoloring agent is melted or solidified in an amorphous state, and the function of dissociating the bond between the leuco dye and the developing agent is exhibited. is there. Therefore, the state change temperature of the decolorizing agent becomes important for the temperature control of the temperature indicating material.

As a material for the decolorizing agent, a wide range of materials capable of dissociating the bond between the leuco dye and the developing agent can be used. Various materials can be decolorants if they have low polarity and do not exhibit color-developing property with respect to leuco dyes, and if the polarity is high enough to dissolve the leuco dye and the developer. Typical decolorants include hydroxy compounds, ester compounds, peroxy compounds, carbonyl compounds, aromatic compounds, aliphatic compounds, halogen compounds, amino compounds, imino compounds, N-oxide compounds, hydroxyamine compounds, and nitro compounds. Various organic compounds such as azo compounds, diazo compounds, azi compounds, ether compounds, fats and oil compounds, sugar compounds, peptide compounds, nucleic acid compounds, alkaloid compounds, and steroid compounds can be used. Specific examples of such a decoloring agent include tricaprine, isopropyl myristate, m-toluic acetate, diethyl sebacate, dimethyl adipate, 1,4-diacetoxybutane, decyl decanoate, diethyl phenylmalonate, and phthalic acid. Diisobutyl, triethyl citrate, benzylbutyl phthalate, butylphthalylbutylglycolate, methyl N-methylanthranylate, ethyl anthranilate, 2-hydroxyethyl salicylate, methyl nicotinate, butyl 4-aminobenzoate, p-toluic acid Examples thereof include ester compounds such as methyl, ethyl 4-nitrobenzoate, 2-phenylethyl phenylacetic acid, benzyl silicate and methyl acetoacetate, and steroid compounds. The decoloring agent preferably contains these compounds from the viewpoint of compatibility with the leuco dye and the color developer. As the decolorizing agent for the temperature indicating material in the present embodiment, only one type of these decoloring agents may be used, or two or more types may be used in combination. By combining a decolorizing agent, it is possible to adjust the freezing point, melting point, glass transition point, crystallization rate, and the like. Further, by combining the decolorizing agent, the coloration temperature of the leuco dye and the color developing agent can be controlled more precisely. Of course, the decolorizing agent that can be used in this embodiment is not limited to these compounds.

In the present embodiment, a decolorizing agent suitable for the temperature indicating material can be appropriately selected according to the required temperature (when the first temperature indicating material and the second temperature indicating material are used, the decolorizing agent suitable for each can be appropriately selected. ). When the first temperature indicating material and the second temperature indicating material are used, the above-mentioned decoloring agent can be commonly used for both the first temperature indicating material and the second temperature indicating material. The amount of the decolorizing agent used is selected according to the desired coloration temperature. The amount of the decolorizing agent used may be selected, for example, in the range of about 10 parts by mass to 100 parts by mass with respect to 1 part by mass of the leuco dye described above.

The state change temperature of the above decolorizing agent is important. As a decolorizing agent for the temperature indicator used for detecting the deviation from the upper limit temperature by forming an amorphous state by quenching, it is necessary to not crystallize in the quenching process but to amorphous in the vicinity of the glass transition point. Therefore, a material that is difficult to crystallize is preferable. Most materials form an amorphous state if the quenching rate is made very high, but in consideration of practicality, a material that is difficult to crystallize to the extent that an amorphous state is formed by quenching with a general-purpose cooling device is preferable. More preferably, a material that is difficult to crystallize to the extent that it forms an amorphous state in the process of naturally cooling from a molten state above the melting point. As this condition, a decoloring agent that forms an amorphous state when cooled from the melting point to the glass transition point at a rate of 100 ° C./min or less is preferable, and cooled from the melting point to the glass transition point at a rate of 20 ° C./min or less. A decoloring agent that sometimes forms an amorphous state is most preferred.

As a decoloring agent for a temperature indicator used for detecting a deviation from the lower limit temperature because it is in a supercooled state below the melting point and exists in a liquid state, the temperature range in the supercooled state is wide, that is, the freezing point and melting point temperature of the decolorizing agent. It is desirable that the difference is large. Further, the temperature of the melting point or the freezing point of the decolorizing agent depends on the target temperature control range.

In order to initialize the function, it is necessary to raise the temperature above the melting points of the decolorizing agent of the temperature indicator used to detect the deviation from the upper limit temperature and the decoloring agent of the temperature indicator used to detect the deviation from the lower limit temperature. The initializing temperature of the function needs to be high enough to be difficult to occur near the control temperature, but considering practicality, it is desirable that the temperature is in a temperature range that can be heated by a general-purpose heating device. Further, as the temperature detection material, a matrix material or a base material for an indicator is used to protect the temperature indicator material, so it is necessary to consider the heat resistance of these materials. Specifically, the initialization temperature of the function is preferably about 40 ° C. to 200 ° C., most preferably about 60 ° C. to 150 ° C.

<Form of temperature detection material>
When the above combination of temperature indicating materials is used as a temperature detecting material, there are a plurality of forms. However, if the temperature indicator used to detect the upper limit temperature deviation (temperature indicator for upper limit detection) and the temperature indicator used to detect the lower limit temperature deviation (temperature indicator for lower limit detection) are mixed in the same matrix material, they will be different. A structure in which they exist separately is required because they interfere with the function. Further, the temperature indicating material for detecting the lower limit develops color when the liquid crystallizes. That is, the structure of the temperature indicating material for the lower limit detection changes. Therefore, the temperature indicating material for detecting the lower limit needs to have a form that protects the liquid from the viewpoint of handleability.

From this point of view, it is generally used to protect the temperature indicator with microcapsules. By microencapsulating the temperature indicator for upper limit detection and the temperature indicator for lower limit detection, respectively, they can be mixed in the same temperature detection material (in the matrix material). Therefore, in this way, it is possible to simultaneously detect the upper limit detection and the lower limit detection with the same temperature detection material.

Further, in the present embodiment, the temperature indicating material may be a solid material (phase-separated structure) protected by a matrix material having neither a coloring effect nor a decolorizing effect. In this case, it is preferable to use two types of the phase-separated structure, one formed of the temperature indicating material for detecting the upper limit and the other formed of the temperature indicating material for detecting the lower limit. In this way, it can be handled in the same manner as microcapsules.

The temperature indicating material for detecting the upper limit develops color when the amorphous state crystallizes. Therefore, the color changes in the solid state. Therefore, the temperature indicating material for detecting the upper limit can be used as a single temperature indicating material. However, it is necessary to melt the temperature indicating material in order to initialize the function, and in that state, it becomes a liquid state, so that it is difficult to handle. For this reason, it is preferable that the temperature indicating material for detecting the upper limit is also microencapsulated or a phase-separated structure.

As described above, as the temperature indicating material for detecting the upper limit, a temperature indicating material microencapsulated, a temperature indicating material having a phase-separated structure, or a temperature indicating material alone is used. Further, as the temperature indicating material for detecting the lower limit, a temperature indicating material microencapsulated and a temperature indicating material having a phase-separated structure are used. Then, by mixing these, a solid material capable of simultaneous detection of upper limit detection and lower limit detection can be obtained.

<Microencapsulation>
By microencapsulating, as described above, the environmental resistance of the composition to humidity and the like is improved, and storage stability and discoloration characteristics can be stabilized. Further, when microencapsulated, the influence of the leuco dye, the color developer and the decoloring agent on the compound such as other resin agents and additives can be suppressed when the resin composition is prepared at the time of production.

Various known methods can be applied to microencapsulation. For example, an emulsification polymerization method, a suspension polymerization method, a coacervation method, an interfacial polymerization method, a spray-drying method and the like can be applied, but the method is not limited thereto. Further, two or more different methods may be combined.
By these methods, microencapsulated thermostats are produced, mixed in the matrix material (mixing step), and cooled (cooling step) to put the microencapsulated thermostats in the matrix material. Including temperature detection material can be manufactured. This method for producing a temperature detection material corresponds to one aspect of the temperature indicating material production process in the method for producing a temperature detection film according to an embodiment of the present invention, which will be described later.

Examples of the resin film used for the microcapsules include a urea resin film composed of a polyvalent amine and a carbonyl compound, a melamine / formalin prepolymer, a methylol melamine prepolymer, a melamine resin film composed of a methylated melamine prepolymer, and a polyvalent isocyanate and a polyol. Urethane resin film made of compound, amide resin film made of polybasic acid chloride and polyvalent amine, vinyl resin film made of various monomers such as vinyl acetate, styrene, (meth) acrylic acid ester, acrylonitrile, vinyl chloride, etc. It can be used, but is not limited to these. Further, in the present embodiment, the surface treatment of the formed resin coating is performed, and the surface energy at the time of preparing the resin composition is adjusted to perform additional treatment such as improving the dispersion stability of the microcapsules. You can also.

The diameter of the microcapsules is preferably in the range of about 0.1 μm to 100 μm, more preferably in the range of 0.1 μm to 10 μm, in consideration of device compatibility, storage stability and the like.

<Phase separation structure>
The phase-separated structure is a solid material obtained by dispersing leuco dye, a color developer, and a decoloring agent, which are temperature-indicating materials, in a matrix material. As a result, storage stability and discoloration characteristics can be stabilized in the same manner as microcapsules by a simple method other than microencapsulation. Further, since the phase-separated structure can be powdered, by using the powdered phase-separated structure, a leuco dye, a color developer, and a decoloring agent are used when the resin composition is prepared at the time of production. Can suppress the influence of compounds such as other resin agents and additives.

4A to 4D show a schematic view of the phase separation structure of the temperature detection film 100 (temperature detection material 120) according to the embodiment of the present invention. Note that FIG. 4A illustrates a state in which the temperature indicating material 121 is colored, and FIG. 4B is an enlarged view of the ivb portion in FIG. 4A. FIG. 4C illustrates a state in which the temperature indicating material 121 is decolorized, and FIG. 4D is an enlarged view of the ivd portion in FIG. 4C.

As shown in FIGS. 4A to 4D, the temperature detection film 100 forms a phase-separated structure in which the temperature indicating material 121 is dispersed in the matrix material 122. That is, the temperature detection film 100 forms a structure in which the phase (temperature indicating material 121) containing the leuco dye, the color developer, and the decoloring agent is dispersed in the matrix material 122.

As will be described later, in the temperature detection film 100 according to the present embodiment, since the melting point B of the matrix material 122 is higher than the melting point A of the temperature indicating material 121 or the decolorizing agent, the solid state is maintained at the discoloration temperature of the temperature indicating material 121. Can be retained. Therefore, even if the temperature indicating material 121 changes its state from solid to liquid and from liquid to solid and a color change occurs, the temperature detection film 100 (temperature detection material 120) is solid as shown in FIGS. 4A to 4D. It remains in a state.

Further, as shown in FIGS. 4B and 4D, the matrix material 122 and the temperature indicating material 121 are phase-separated, and the matrix material 122 does not affect the color change of the temperature indicating material 121. The temperature detection function can be maintained as it is.

The major axis of the phase composed of the temperature indicating material 121 dispersed in the matrix material 122 is preferably 100 nm or more and 1 mm or less, and more preferably 1 μm or more and 100 μm or less. The major axis of the phase made of the temperature indicating material 121 is not particularly limited, but by setting it to 100 nm or more, the influence of the interface between the temperature indicating material 121 and the matrix material 122 on the detected temperature can be suppressed. Further, by setting the major axis of the phase made of the temperature indicating material 121 to 1 mm or less, it becomes difficult to distinguish and visually recognize the temperature indicating material 121 and the matrix material 122, and it is possible to suppress color unevenness of the temperature detecting material 120. The major axis of the phase made of the temperature indicating material 121 can be reduced by adding a surfactant or cooling with stirring in the cooling step performed in the initial decolorization state. The major axis of the phase composed of the temperature indicating material 121 is the major axis of the approximate ellipse when the phase composed of the temperature indicating material 121 is approximated to an ellipse.

The phase-separated structure can also be crushed in a mortar or the like to be pulverized. This enables the same handling as microcapsules.

<Manufacturing method of phase-separated structure>
Examples of the method for producing the phase-separated structure include a mixing step and a cooling step, and these steps are performed in this order. The method for producing the phase-separated structure corresponds to one aspect of the temperature indicating material manufacturing process in the method for manufacturing the temperature detection film according to the embodiment of the present invention, which will be described later.

In the above-mentioned mixing step, the leuco dye, the color developer, the decoloring agent, and the matrix material 122 are heated to a temperature equal to or higher than the melting point of the matrix material 122 and mixed.
Then, in the cooling step described above, the mixture obtained in the mixing step is cooled to a temperature equal to or lower than the freezing point of the matrix material 122. In this cooling step, the matrix material 122 and the temperature indicating material 121 are rapidly separated from each other, and a phase-separated structure in which the phases consisting of the leuco dye, the color developer, and the decolorizing agent are dispersed is formed in the matrix material 122. To.
When the first temperature indicating material and the second temperature indicating material are used, each of the temperature indicating materials 121 may be manufactured by performing the above-mentioned mixing step and cooling step.

When the matrix material 122 is heated to a liquid state by heating to a temperature higher than the melting point of the matrix material 122 in the mixing step, the temperature indicating material 121 and the non-color-developing material are compatible with each other depending on the compatibility between the temperature indicating material 121 and the matrix material 122. It may not be. At this time, it is preferable that they are compatible with each other from the viewpoint of ease of handling. The temperature indicating material 121 and the matrix material 122 need to be phase-separated when the matrix material 122 is in a solid state at an operating temperature, but this is not the case when the matrix material 122 is in a liquid state in a heated state. In order for the temperature indicating material 121 and the matrix material 122 to be phase-separated at the operating temperature and the temperature indicating material 121 and the matrix material 122 to be compatible with each other in a heated state, the polarity of the decolorizing agent having a particularly high content must be within a certain range. It would be nice to have it. If the polarity of the decolorizing agent is too small, it will be compatible with the matrix material 122 at the operating temperature, and if the polarity is too large, it will be separated from the matrix material 122 in the heated state.

Hansen solubility parameter can be mentioned as a specific method for calculating the polarity of the decolorizing agent. In the present embodiment, a decolorizing agent in which the energy δd due to the dipole interaction between molecules and the energy δh due to the hydrogen bond between molecules, which are predicted by the Hansen solubility parameter, are 1 or more and 10 or less, respectively, can be preferably used. Even for a material having a large polarity of the decolorizing agent and the temperature indicating material 121 and the matrix material 122 are incompatible with each other even in a heated state, a phase separation structure can be formed by cooling with stirring. Further, a phase-separated structure can be formed even if a surfactant is added and compatible with each other.

When cooling below the freezing point of the matrix material 122 to form a phase-separated structure, the size (major axis of the phase) of the dispersed structure of the temperature indicating material 121 can be adjusted by the compatibility between the temperature indicating material 121 and the matrix material 122. .. For example, the decolorizing agent having a high content and the matrix material 122 are finely dispersed when the compatibility is good to some extent, and largely dispersed when the compatibility is poor. The size of the dispersed structure (major axis of the phase) is not particularly limited, but as described above, it is preferably 100 nm or more and 1 mm or less, and more preferably 1 μm or more and 100 μm or less. In order to realize this dispersed structure, as described above, the energy δd due to the dipole interaction between molecules and the energy δh due to the hydrogen bond between molecules, which are predicted by the Hansen solubility parameter, are 1 or more and 10 or less, respectively. It is preferable to use an agent.

(Matrix material)
The matrix material 122 needs to be a material that does not impair the color-developing and decolorizing properties of the temperature-indicating material 121 when mixed with the temperature-indicating material 121. Therefore, it is preferable that the material itself does not exhibit color development. As such a material, a non-polar material that is not an electron acceptor can be used.

Further, when forming a phase-separated structure in which the temperature indicating material 121 is dispersed in the matrix material 122, it is necessary to use a material satisfying the following three conditions as the matrix material 122.
The three conditions are that the temperature detection material 120 is in a solid state at the operating temperature (discoloration temperature), the melting point B is higher than the melting point A of the temperature indicating material 121 or the decoloring agent, and the leuco dye, the color developer and the decoloring agent. It is a material that has low compatibility with colorants. If any of the leuco dye, the color developer, and the decolorizing agent is in a solid solution state with the matrix material 122, the temperature detection function is impaired. Further, by using the matrix material 122 in a solid state at the operating temperature, the temperature detection material 120 can be easily handled.

Further, in the present embodiment, the temperature detecting material 120 including the matrix material 122 and the temperature indicating material 121 needs to have physical properties that can be formed into a film.

As the matrix material 122 satisfying the above conditions, a material having an energy δd due to an intermolecular dipole interaction and an energy δh due to an intermolecular hydrogen bond predicted by the Hansen solubility parameter can be preferably used. .. As such a matrix material 122, a polyolefin-based polymer can be used. In this way, the melt flow rate described later can be set within a predetermined range. In the present specification, the polyolefin-based polymer is a molecule synthesized by using simple olefins or alkenes as a monomer, and is a long-chain molecule composed of C, H, and O. Those containing some double bonds are also treated as polyolefins in a broad sense. Specifically, the polyolefin-based polymer means a polymer having a molecular weight of 10,000 or more, preferably 10,000 to 1,000,000.

Specifically, the matrix material 122 is preferably a material composed only of hydrocarbons, and more preferably a material having no polar group. Examples of such matrix material 122 include polypropylene, polyethylene or polystyrene. Further, the matrix material 122 described above can be used in combination of a plurality of types. In the present embodiment, a polymer material having a large number of polypropylene, polyethylene, or polystyrene skeletons, a copolymer thereof, and the like can also be preferably used.

Further, the matrix material 122 is easy to handle as a material that dissolves in an organic solvent and solidifies in the process of volatilizing the organic solvent. From these viewpoints as well, it is preferable to use a polymer material having many skeletons such as polypropylene, polyethylene or polystyrene as the matrix material 122.

Since the temperature detection film 100 according to the present embodiment is formed into a film by using the temperature detection material 120 including the matrix material 122 and the temperature indicating material 121, the fluidity of the melted resin has the function of the temperature detection film 100 and the function of the temperature detection film 100. It greatly affects the moldability. As a method for evaluating the fluidity of a resin, there is a standardized (JIS K7210) melt flow rate. Specifically, this melt flow rate is obtained by applying a load of 2.16 kg to a resin heated to 190 ° C. in a cylinder and using the amount of the resin flowing out of the pores in 10 minutes as an index. When the melt flow rate of the resin obtained by mixing the matrix material 122 and the temperature indicating material 121 is 0.5 g / 10 min or more and 50 g / 10 min or less, both the mixing property of the matrix material 122 and the temperature indicating material 121 and the film formability can be achieved. The melt flow rate described above is selected so as to fall within this range regardless of whether the temperature detection material 120 is obtained by microencapsulation or phase separation structure formation. The melt flow rate described above is preferably 0.5 g / 10 min or more and 10 g / 10 min or less. In this way, the mixability of the matrix material 122 and the temperature indicating material 121 and the film formability can be compatible with each other at a higher level.

In the temperature detection film 100 according to the present embodiment, the relationship between the melting point A of the temperature indicating material 121 or the decoloring agent and the melting point B of the matrix material 122 is melting point B-melting point A> 30 ° C. Here, if the melting point A of the temperature indicating material 121 and the melting point A of the decolorizing agent are different, the lower melting point may be applied, and if these melting points are the same, which melting point is applied. May be good. In this way, since the melting point B of the matrix material 122 is higher than the melting point A of the temperature indicating material 121 or the decolorizing agent, the solid state can be maintained at the discoloration temperature of the temperature indicating material 121. Therefore, even if the temperature indicating material 121 changes its state from solid to liquid and from liquid to solid and a color change occurs, the temperature detection film 100 (temperature detection material 120) remains in the solid state. In this way, even when the temperature indicating material 121 is set to a temperature at which the state changes, the temperature detection film 100 (temperature detection material 120) remains in a solid state, so that the temperature detection film 100 (temperature detection material 120) remains in a solid state. 120) The molecule becomes difficult to move. Therefore, the molecular motion of the temperature indicating material 121 is also slowed down, so that the temperature detection film 100 according to the present embodiment can lengthen the temperature detection time. From the same viewpoint, the relationship between the melting point A and the melting point B is preferably melting point B-melting point A> 40 ° C, more preferably melting point B-melting point A> 50 ° C.

In the temperature detection film 100 according to the present embodiment, the content of the matrix material 122 is 50% by mass or more (when the temperature detection material 120 constituting the temperature detection film 100 is 100% by mass, the matrix material 122 The content is 50% by mass or more). In other words, the content of the temperature indicating material 121 is less than 50% by mass. In this way, the dispersibility of the temperature indicating material 121 in the matrix material 122 is increased. Further, in this way, the matrix material 122 can hold the temperature indicating material 121 and can secure the visibility as the temperature detecting material 120. Further, in this way, the temperature detecting material 120 can be suitably solidified, so that the temperature detecting material 120 can be easily formed into a film. The content of the matrix material 122 in the temperature detection film 100 (temperature detection material 120) is preferably 70% by mass or more and 95% by mass or less. In this way, in addition to making the dispersibility and film formation more suitable, the processability of the temperature detection film 100 is improved.

The components of the temperature indicating material 121 and the types and contents of the matrix material 122 can be easily confirmed by using an apparatus capable of analyzing the components such as a nuclear magnetic resonance apparatus and a mass spectrometer.
Further, the melting point A of the temperature indicating material 121 or the decoloring agent and the melting point B of the matrix material 122 can be measured by, for example, a differential scanning calorimeter (DSC). For the measurement, for example, a weighed sample of 10 mg for measuring the melting point is placed on an aluminum pan, the temperature is lowered to -40 ° C, the temperature is maintained at -40 ° C for 5 minutes, and then the temperature is raised to 200 ° C at 5 ° C / min. , It can be easily confirmed by extracting the temperature at which the endothermic peak falls due to melting from the change diagram of the heat flow with respect to the obtained temperature.

(Manufacturing method of temperature detection film)
Next, a method for manufacturing a temperature detection film according to an embodiment of the present invention will be described.
FIG. 5 is a flowchart illustrating the contents of a method for manufacturing a temperature detection film according to an embodiment of the present invention.
As shown in FIG. 5, the present manufacturing method includes a temperature indicating material manufacturing step S1, a temperature detecting material manufacturing step S2, and a temperature detecting film manufacturing step S3, and these steps are performed in this order.

The temperature indicating material manufacturing step S1 is a step of producing the temperature indicating material 121 using a leuco dye, a color developer, and a decoloring agent. In this temperature indicating material manufacturing step S1, it is preferable to disperse the temperature indicating material 121 in the matrix material 122 in at least one state of phase-separated structure formation and microencapsulation by the method described above.
Then, in the temperature detection material manufacturing step S2, while the matrix material 122, which is a polyolefin-based polymer, is thermally melted, the temperature indicating material 121 produced in the temperature indicating material manufacturing step S1 is added and kneaded to produce the temperature detecting material 120. It is a process.
The temperature indicating material manufacturing step S1 and the temperature detecting material manufacturing step S2 can be performed using any mixer or the like.

The temperature detection film manufacturing step S3 is a step of cooling and solidifying the temperature detection material 120 kneaded in the temperature detection material manufacturing step S2, and then molding the temperature detection film 100 into a predetermined shape to manufacture the temperature detection film 100.
The temperature detection material 120 can be cooled by cooling it to a temperature equal to or lower than the freezing point of the matrix material 122 by using a general-purpose cooling device or natural cooling (natural cooling). When cooling, it is preferable to adjust the solidified temperature detection material 120 so as to have a desired thickness dimension. Then, the temperature detection film 100 having a desired shape can be formed by appropriately cutting or punching. Further, in the temperature detection film manufacturing process S3, the temperature detection material 120 kneaded in the temperature detection material manufacturing step S2 may be poured into a predetermined mold and cooled to form a temperature detection film 100 having a predetermined shape. ..

In the present production method, in the temperature indicating material 121 and the matrix material 122, the relationship between the melting point A of the temperature indicating material 121 or the decoloring agent and the melting point B of the matrix material 122 is melting point B-melting point A> 30 ° C. The materials are selected so that the melt flow rate of the temperature detection film 100 is 0.5 g / 10 min or more and 50 g / 10 min or less. The selection of these materials can be appropriately made by those skilled in the art based on the description herein. Further, in the present manufacturing method, the content of the matrix material 122 in the temperature detection material manufacturing step S2 is set to 50% by mass or more. In this way, the temperature detection film 100 according to the above-described embodiment can be suitably manufactured by the present manufacturing method.

As described above, the temperature detection film 100 according to the present embodiment specifies the matrix material 122 and its content, and further sets the melt flow rate in a specific range. Therefore, the temperature detection material 120 Film formation can be preferably performed. Since the film can be suitably formed in this way, the temperature detection film 100 according to the present embodiment can be used by itself, and requires members such as a base material, a transparent base material, and a spacer like a temperature detection label. Because it does not, the cost can be reduced.
Further, since the temperature detection film 100 has a specific range of the relationship between the melting point A of the temperature indicating material 121 or the decoloring agent and the melting point B of the matrix material 122, the temperature detection time can be lengthened.
The method for producing the temperature detection film according to the present embodiment can suitably produce the temperature detection film 100 according to the present embodiment that exhibits these effects.

<Temperature indicator>
As described above, the temperature detection film 100 according to the present embodiment can be used by itself, can be used at low cost and can prolong the temperature detection time, but is stronger when long-term use is considered. It is conceivable that there is a desire to increase the temperature and prevent deterioration of the material.
Therefore, the temperature detection film 100 according to the present embodiment may be attached to a base material (not shown) such as resin, glass, or metal, or covered with a transparent base material and a spacer (not shown). Therefore, it is possible to use a temperature indicator (not shown) capable of simultaneously detecting the upper limit detection and the lower limit detection. As described above, when the temperature detection film 100 according to the present embodiment is used as the temperature indicator, the temperature detection time can be lengthened for the reason described above, so that the temperature detection time is further longer than that of the temperature detection film 100 or the conventional temperature indicator. Can be lengthened.

Next, the effect of the present invention will be described with reference to Examples and Comparative Examples. The present invention is not limited to these examples.

(Example 1)
Polypropylene (PP) having a melt flow rate of 2.5 g / 10 min and a temperature indicator composed of a leuco dye, a developer and a decoloring agent are mixed at 85% by mass: 15% by mass and heat-melted to have a thickness of 400 μm. The temperature detection film according to Example 1 was produced by molding the film. The temperature detection film according to Example 1 is applied with a temperature-indicating material that develops color when the temperature rises to 8 ° C. or higher, and the color changes uniformly when left at room temperature after initialization. In the temperature detection film according to Example 1, the relationship between the melting point A of the decolorizing agent and the melting point B of PP (matrix material) was melting point B-melting point A = 40 ° C., and thus is shown in FIGS. 6A to 6C. As described above, it was confirmed that the film shape could be maintained in both the initial state and the developed state (it remained in the solid state).

Note that FIG. 6A is a photograph of the temperature detection film according to Example 1 taken from above in a state (initial state) before color development immediately after production (stored at room temperature for 0 hours). FIG. 6B is a photograph of the temperature detection film according to Example 1 taken from above in a state of being stored at room temperature for 5 days (stored for about 120 hours) and developed into a color. FIG. 6C is a photograph taken from the side of the temperature detection film according to the first embodiment shown in FIG. 6B. In FIGS. 6A to 6C, the scale bars at the lower right represent 10 mm. Further, as shown in FIG. 6C, the thickness of the temperature detection film according to the first embodiment is 400 μm (t = 400 μm). As described above, it was confirmed that the temperature detection film according to Example 1 can maintain the film shape in both the initial state and the color-developed state as shown in FIGS. 6A to 6C.

(Extraction of detection temperature and detection time)
Then, the temperature detection film according to Example 1 described above was stored at 8 ° C., 15 ° C., 25 ° C., and 50 ° C., and the time when the color was 50% concentrated was extracted. The color density was determined by extracting R (red), G (green), and B (blue) values from the captured image using dedicated image analysis software (open source ImageJ). Since the dye used this time is blue, the value read from the image was introduced into the formula of 3B / (R + G + B) for calculation. The color density immediately after initialization is 0%, the color density left sufficiently at room temperature until the color does not change is 100%, and the color density in the middle is 50%. It was judged.

(Example 2)
Using the same material as the temperature detection film according to Example 1, PP and the temperature indicating material are mixed at 70% by mass: 30% by mass, heat-melted, and film-formed to a thickness of 400 μm to form the temperature according to Example 2. Manufactured a detection film. Then, using the temperature detection film according to Example 2, the detection temperature and the detection time were extracted under the same conditions and criteria as in Example 1. It was confirmed that the temperature detection film according to Example 2 also maintained the film shape in both the initial state and the color development state (it remained in the solid state).

(Example 3)
Using the same material as the temperature detection film according to Example 1, PP and a temperature indicating material are mixed at 50% by mass: 50% by mass, heat-melted, and film-formed to a thickness of 400 μm to form a film at a temperature according to Example 3. Manufactured a detection film. Then, using the temperature detection film according to Example 3, the detection temperature and the detection time were extracted under the same conditions and criteria as in Example 1. It was confirmed that the temperature detection film according to Example 3 also maintained the film shape in both the initial state and the color development state (it remained in the solid state).

(Example 4)
PP having a melt flow rate of 50 g / 10 min and a temperature indicator composed of a leuco dye, a developer and a decoloring agent are mixed at 70% by mass: 30% by mass, heat-melted, and film-formed to a thickness of 400 μm. , A temperature detection film according to Example 4 was manufactured. Then, using the temperature detection film according to Example 4, the detection temperature and the detection time were extracted under the same conditions and criteria as in Example 1. It was confirmed that the temperature detection film according to Example 4 also maintained the film shape in both the initial state and the color development state (it remained in the solid state).

(Example 5)
Polyethylene (PE) having a melt flow rate of 0.5 g / 10 min and a temperature indicator composed of a leuco dye, a developer and a decoloring agent are mixed at 70% by mass: 30% by mass and heat-melted to have a thickness of 400 μm. The temperature detection film according to Example 5 was produced by molding the film. Then, using the temperature detection film according to Example 5, the detection temperature and the detection time were extracted under the same conditions and criteria as in Example 1. It was confirmed that the temperature detection film according to Example 5 also maintained the film shape in both the initial state and the color development state (it remained in the solid state).

(Comparative Example 1)
A low melting point (low molecular weight) polyethylene wax (WAX) having a melt flow rate of more than 50 g / 10 min and a temperature indicator composed of a leuco dye, a color developer and a decoloring agent are mixed at 70% by mass: 30% by mass. It was heat-melted and poured into an aluminum mold to solidify and mold it to a thickness of 400 μm to produce a flaky temperature-sensing material according to Comparative Example 1 (in a solid wax state). The relationship between the melting point A of the decolorizing agent and the melting point B of the polyethylene wax of the matrix material was melting point B-melting point A ≤ 30 ° C., which was a solid in the developed state but a liquid state in the initial state. Then, the temperature detection material according to Comparative Example 1 was stored at 25 ° C., and the detection temperature and the detection time were extracted under the same conditions and criteria as in Example 1.

(Comparative Example 2)
PP having a melt flow rate of more than 50 g / 10 min and a temperature indicator composed of a leuco dye, a developer and a decoloring agent are mixed at 70% by mass: 30% by mass, heat-melted, and film-formed to a thickness of 400 μm. Therefore, the temperature detection film according to Comparative Example 2 was manufactured. Then, using the temperature detection film according to Comparative Example 2, the detection temperature and the detection time were extracted under the same conditions and criteria as in Example 1. It was confirmed that the film according to Comparative Example 2 could maintain the film shape (it remained in a solid state), but did not show color development even at 2100h (does not show color development).

(Comparative Example 3)
A polyethylene wax (WAX) having a melt flow rate of 0.5 g / 10 min or more and 50 g / 10 min or less and a temperature indicator composed of a leuco dye, a color developer and a decoloring agent are mixed at a ratio of 30% by mass: 70% by mass and heated. Although it melted, this material (material according to Comparative Example 3) could not be formed into a film (cannot be formed into a film). The material according to Comparative Example 3 was a solid in the developed state, but was in a semi-solid state in the initial state.

Table 1 shows the conditions of the temperature detection films (type and content (mass%) of matrix material) according to Examples 1 to 5 and Comparative Examples 1 to 3, and 8 ° C., 15 ° C., 25 ° C., and 50 ° C., respectively. The result of extracting the time when the color was stored at a temperature and the color became 50% concentrated is shown. In addition, "-" in Table 1 indicates that time was not extracted.

As shown in Table 1, since the temperature detection films according to Examples 1 to 5 satisfy the requirements of the present invention, Comparative Example 1 (specifically, the melt flow rate is the upper limit) that does not satisfy the requirements of the present invention. It was confirmed that the detection time (temperature detection time) can be made longer than that of Comparative Example 1) in which the matrix material used a low molecular weight polyethylene wax. Further, as described above, the temperature detection films according to Examples 1 to 5 were able to maintain the film shape in both the initial state and the color development state, so it was confirmed that the temperature detection film alone can be used. Was done. Therefore, the temperature detection film satisfying the requirements of the present invention is lower than the conventional temperature detection label (temperature indicator) which requires members such as a base material, a transparent base material, and a spacer because it does not require these members. It was confirmed that the cost could be reduced.

Although the temperature detection film and the method for producing the same according to the present invention have been described in detail with reference to the embodiments and examples, the gist of the present invention is not limited to this, and various modifications are included. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

100 Temperature detection film 120 Temperature detection material 121 Temperature indicator 122 Matrix material

Claims (5)

Includes a matrix material and a temperature-indicating material dispersed in the matrix material.
The matrix material is a polyolefin-based polymer and is
The temperature indicating material contains a leuco dye, a color developer, and a decoloring agent.
The relationship between the melting point A of the temperature indicating material or the decoloring agent and the melting point B of the matrix material is melting point B-melting point A> 30 ° C.
The content of the matrix material is 50% by mass or more, and the content is 50% by mass or more.
A temperature detection film having a melt flow rate of 0.5 g / 10 min or more and 10 g / 10 min or less. In claim 1,
A temperature detection film in which the polyolefin-based polymer is at least one of polypropylene, polyethylene, and polystyrene. In claim 1,
A temperature detection film in which the content of the matrix material is 70% by mass or more and 95% by mass or less. In claim 1,
A temperature detection film in which the temperature indicating material is dispersed in the matrix material in at least one state of phase-separated structure formation and microencapsulation. A temperature-indicating material manufacturing process for producing a temperature-indicating material using a leuco dye, a color developer, and a decolorizing agent.
A temperature detection material manufacturing process for manufacturing a temperature detection material by adding and kneading the manufactured temperature indicating material while thermally melting a matrix material which is a polyolefin-based polymer.
A temperature detection film manufacturing process in which the kneaded temperature detection material is cooled and hardened, and then molded into a predetermined shape to manufacture a temperature detection film.
Including
In the temperature indicating material and the matrix material, the relationship between the melting point A of the temperature indicating material or the decoloring agent and the melting point B of the matrix material is melting point B-melting point A> 30 ° C., and the melt of the temperature detection film. Select materials having a flow rate of 0.5 g / 10 min or more and 10 g / 10 min or less, respectively.
A method for producing a temperature detection film in which the content of the matrix material in the temperature detection material manufacturing process is 50% by mass or more.

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