JP6197537B2 - Thermal history display material - Google Patents

Description

  The present invention relates to a heat history display material for displaying a heat history experienced by an article, and more specifically, includes a heat history display layer containing a predetermined dye, and changes in hue of the heat history display layer. The present invention relates to a heat history display material capable of displaying a heat history experienced by an article.

  For the purpose of managing the storage state, quality or safety of articles such as various products and foods, a temperature indicating material whose hue changes with temperature changes is attached to the article, and the temperature change experienced by the article is indicated. A technique for grasping from a hue change of a material is conventionally known (for example, Patent Document 1).

  However, the conventional temperature indicating material has a very complicated structure. Also, although the experienced temperature change can be displayed, the thermal history is not displayed, that is, the hue change based on the experienced temperature and the history of the time placed under that temperature (temperature-time history). It wasn't something to do.

  As a temperature indicating material capable of solving the above-mentioned conventional problems, for example, Patent Documents 2 to 4 include a temperature including a polymer composition composed of a polymer and a dye fixed in a specific molecular dispersion state in the polymer. A time history display body and the like are described. When the temperature / time history display body is held at a temperature equal to or higher than a specific temperature for a certain period of time, the color is irreversibly changed to a hue different from the initial hue.

JP 07-049656 A JP 2009-299013 A JP 2009-3000986 A JP 2009-298470 A

  The above-described thermal history display material such as a temperature / time history display body can be suitably applied to an application in which the thermal history (temperature-time history) of the article is displayed by hue change by being attached to a certain article. Somewhere, it is required that the heat history of the article can be accurately displayed.

  However, the present inventors have found that when the temperature time history display body is exposed to ultraviolet rays, the irreversible discoloration as described above may not occur and does not function normally as a heat history display agent. I found out that there was a fear.

  Therefore, an object of the present invention is to provide a heat history display material capable of accurately displaying the heat history (temperature-time history) of an article by changing the hue even when exposed to ultraviolet rays.

The present invention provides the following heat history display material.
[1] A thermal history display layer in which an associative fluorescent dye having different fluorescence wavelengths in an excimer state and a monomer state is fixed in a specific molecular dispersion state,
A heat history display material comprising an outer resin layer having ultraviolet absorptivity on at least one surface side of the heat history display layer.

  [2] The heat history display material according to [1], wherein the heat history display layer contains a binder resin and the fluorescent dye dispersed in the binder resin.

  [3] The heat history display material according to [2], wherein the binder resin has an acid value of 0.5 to 45 eq / 1 t.

[4] The heat history display material according to any one of [1] to [3], further including a base material.
[5] The substrate has a through-hole penetrating in the thickness direction,
The heat history display layer according to [4], wherein the heat history display layer is embedded in the through hole.

  [6] The heat history display material according to any one of [1] to [5], further including an organic thin film layer on a side opposite to the outer resin layer of the heat history display layer.

  [7] The heat history display material according to any one of [1] to [6], further including an adhesive resin layer on the outermost surface of the heat history display layer opposite to the outer resin layer.

  [8] The heat history display material according to any one of [1] to [7], wherein in the heat history display layer, molecules of the fluorescent dye are fixed in a monomer state.

  [9] The fluorescent dye has the following formula:

(In the formula, each R independently represents hydrogen, an alkyl group having 1 to 36 carbon atoms, an alkoxy group having 1 to 36 carbon atoms, a hydroxyl group, a hydroxyalkyl group, a halogen group, a phenylene vinylene group or a cyano group.
Each R ₁ independently represents hydrogen, an alkyl group having 1 to 36 carbon atoms, an alkoxy group having 1 to 36 carbon atoms, a hydroxyl group, a hydroxyalkyl group, a halogen group, a phenylene vinylene group or a cyano group;
Each R ₂ independently represents hydrogen, an alkyl group having 1 to 36 carbon atoms, an alkoxy group having 1 to 36 carbon atoms, a hydroxyl group, a hydroxyalkyl group, a halogen group, a phenylene vinylene group or a cyano group. )
The heat history display material according to any one of [1] to [8], which is an oligophenylene vinylene compound represented by:

  [10] A heat history display material with a release layer, comprising the heat history display material according to [7] and a release layer laminated on the surface of the adhesive resin layer opposite to the outer resin layer.

  The heat history display material (label) of the present invention includes a heat history display layer that irreversibly discolors to a hue different from the initial hue when held for a certain period of time at a temperature equal to or higher than a specific temperature. The thermal history (temperature-time history) experienced by can be accurately displayed by the hue change of the thermal history display layer. By sticking such a thermal history display material to an article, the thermal history of the article, that is, the history of elapsed time above a specific temperature (whether it has been held for a certain period of time at a temperature above a specific temperature) Can be accurately and easily determined by the hue change of the heat history display layer.

  In particular, the heat history display material of the present invention comprises an outer resin layer made of a resin having ultraviolet absorptivity, so that it is left for a long period of time under an ultraviolet ray (for example, outdoors, fluorescent lamps, LEDs, incandescent bulbs). Even if it is), the thermal history (temperature-time history) of the article can be accurately displayed by the hue change.

It is sectional drawing which shows typically one Embodiment of the heat history display material which concerns on this invention. It is a top view which shows typically the base material used for the heat history display material shown by FIG.

Hereinafter, an embodiment will be shown and the heat history display material according to the present invention will be described in detail.
FIG. 1 is a cross-sectional view schematically showing an embodiment of a heat history display material according to the present invention. The heat history display material 1 shown in FIG. 1 contains an outer resin layer 10; a fluorescent dye, and irreversibly discolors to a hue different from the initial hue when held for a certain period of time at a temperature above a specific temperature. The heat history display layer 20; the organic thin film layer 40 is included in this order. Moreover, the base material 30 is arrange | positioned so that the side surface of the heat history display layer 20 may be coat | covered, and the adhesive resin layer 50 laminated | stacked on the surface on the opposite side to the heat history display layer 20 in the organic thin film layer 40 is further provided. I have.

(1) Thermal history display layer The thermal history display layer 20 is a layer in which a predetermined fluorescent dye is fixed in a specific molecular dispersion state. It has the property of irreversibly changing to a hue different from the hue. In order to express such properties, in the present invention, associative fluorescent dyes having different fluorescence wavelengths in the excimer state and the monomer state are used as the fluorescent dye.

  The associative fluorescent dye has a different hue depending on its molecular dispersion state. Even when the thermal history display layer 20 is formed using the fluorescent dye in a specific molecular dispersion state, the thermal history display is performed. The specific molecular dispersion state can be maintained in the layer 20. When the heat history display material containing such a fluorescent dye is held at a specific temperature or higher for a predetermined time or longer, the molecular dispersion state of the fluorescent dye molecules contained in the heat history display layer 20 changes, and as a result, the fluorescent dye Therefore, the hue of the heat history display layer 20 changes.

  Associative fluorescent dyes having different fluorescence wavelengths in the excimer state and the monomer state are usually the same when the fluorescent dye molecules are close to each other and when one of them absorbs light and enters an excited state, the other ground state molecule and excimer (Excited aggregate) is formed, and excimer emission on the longer wavelength side than monomer emission is exhibited.

  The “excimer state” is a state in which a plurality of fluorescent dye molecules are associated with or in close proximity to each other, and light emission by a single fluorescent dye molecule is caused by energy transfer between molecules when the fluorescent dye molecules are associated with or in close proximity to each other. It means a state that causes light emission (excimer light emission) at a longer wavelength than (monomer light emission). On the other hand, the “monomer state” means that since the fluorescent dye molecules are separated from each other than the excimer state, energy transfer between the fluorescent dye molecules does not occur, and light emission (monomer light emission) of the fluorescent dye molecules at that time is simply It means a state corresponding to light emission when one excited molecule returns to the ground state.

  The boundary between the monomer state and the excimer state transition is continuous. Therefore, in the transition from the monomer state to the excimer state or the transition from the excimer state to the excimer monomer state, the fluorescent dye molecule partially passes through a state in which the monomer state and the excimer state are mixed. The hue of light appears to change continuously (or stepwise). When the hue of the heat history display layer 20 changes color continuously (or stepwise) in accordance with the heat history (temperature-time history), the detailed heat history of the article to which the heat history display material is attached is known. It is preferable in that it can be performed.

  The fluorescent dye used in the present invention has both excimer emission and monomer emission in the visible region. Accordingly, the heat history display layer 20 can be imparted with a property of changing to a hue different from the initial hue when held at a temperature equal to or higher than a specific temperature for a certain period of time.

  The difference in the maximum fluorescence wavelength between excimer emission and monomer emission of the fluorescent dye is preferably greater than 100 nm. More preferably, it is 120 nm or more, and most preferably 150 nm or more. If the difference in maximum fluorescence wavelength is 100 nm or less, the hue change when held at a temperature above a specific temperature for a certain period of time is small, and it may be difficult to visually identify the hue change.

  Since the hue of the heat history display layer 20 can be easily confirmed visually, the fluorescent dye is preferably capable of emitting fluorescence when excited by light in the visible region. Thereby, the hue of the heat history display layer 20 can be easily visually identified under a normal environment where the article is placed (under illumination or sunlight). The wavelength of visible light that can be absorbed by the fluorescent dye in the monomer state and the absorbance at that wavelength, and the wavelength of visible light that can be absorbed by the fluorescent dye in the excimer state and the absorbance at that wavelength may be the same, or at least Some may be different.

  The fluorescent dyes preferably used that can be excited by visible light and emit fluorescence in the visible region in both the monomer state and the excimer state are oligophenylene vinylene compounds. Among them, as the oligophenylene vinylene compounds that are relatively noticeable in hue change and easy to visually confirm, the following formula:

The compound represented by these can be mentioned. In the above formula, each R independently represents hydrogen, an alkyl group having 1 to 36 carbon atoms, an alkoxy group having 1 to 36 carbon atoms, a hydroxyl group, a hydroxyalkyl group, a halogen group, a phenylene vinylene group or a cyano group, and R ₁ independently represents hydrogen, an alkyl group having 1 to 36 carbon atoms, an alkoxy group having 1 to 36 carbon atoms, a hydroxyl group, a hydroxyalkyl group, a halogen group, a phenylene vinylene group or a cyano group, and R ₂ each independently And hydrogen, an alkyl group having 1 to 36 carbon atoms, an alkoxy group having 1 to 36 carbon atoms, a hydroxyl group, a hydroxyalkyl group, a halogen group, a phenylene vinylene group or a cyano group.

In the above formula, R is preferably a hydrogen hydroxyl group, more preferably hydrogen. R ₁ is preferably an alkoxy group having 1 to 36 carbon atoms, and more preferably an alkoxy group having 15 to 36 carbon atoms. R ₂ is preferably an alkoxy group having 1 to 36 carbon atoms, and more preferably an alkoxy group having 1 to 3 carbon atoms.

  The heat history display layer 20 is preferably a layer containing a binder resin together with a fluorescent dye. In this case, the fluorescent dye is dispersed and fixed in the binder resin in the heat history display layer 20.

  As the binder resin, a resin having translucency and capable of uniformly dissolving and dispersing the fluorescent dye is selected. The binder resin is preferably a resin whose physical properties reversibly change with heating and cooling, and is preferably a solvent-soluble resin or a thermoplastic resin from the viewpoint of processability and the like. The glass transition temperature of the binder resin is preferably 50 ° C. or higher from the viewpoint of processability and the like.

  Specific examples of binder resins that are preferably used include polyolefin resins (polyethylene, polypropylene, etc.); cycloolefin resins; polyester resins (polyethylene terephthalate (PET), a copolymer of PET and 1,4-cyclohexanedimethanol ( PETG), polybutylene terephthalate, polyethylene naphthalate, etc.); polycarbonate resin; polyimide resin; polyamideimide resin; polyetherimide resin; polyurethane resin; polyvinyl resin (polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoro) Ride, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl acetate, polyvinyl alcohol, poly 2-vinyl pyridine, polyvinyl butyral, etc.); polystyrene tree Polyamide resin (nylon 6, nylon 6.6, nylon 12, nylon 4.6, etc.); polyacrylonitrile resin; acrylic resin (polyacrylic acid resin, polymethyl methacrylate, polymethacrylate, polybutyl acrylate, etc.) Polyacrylate resins, etc.); polyacetal resins; polyacrylamide resins; polyglycol resins; copolymer resins (acrylonitrile butadiene styrene, ethylene vinyl acetate, etc.); polyallylsulfone resins; polyphenylene oxide resins; thermosetting resins; Regenerated cellulose resin (cellophane, cellulose acetate, cellulose acetate butyrate, etc.); natural fibers (wool, silk, cotton, etc.); and elastomers such as styrene butadiene copolymer, polybutadiene, ethylene Including emissions propylene copolymer, polychloroprene, polyisoprene, nitrile rubber, silicone rubber, thermoplastic elastomer, a homopolymer or copolymer of synthetic polymers like. Biodegradable polymers such as gelatin, cellulose, polylactic acid, polycaprolactone, modified polyvinyl alcohol, and casein, and hydrocarbon compounds such as paraffin can also be used. Among these, it is preferable to use polyesters, and it is particularly preferable to use PET and PETG.

  In the heat history display layer 20, the binder resin and the fluorescent dye preferably have appropriate compatibility (affinity). “Moderate compatibility (affinity)” means the initial state when the binder resin and the fluorescent dye fixed in a specific molecular dispersion state in the binder resin are held at a temperature higher than a specific temperature for a certain period of time. It is compatible to such a degree that it irreversibly changes to a hue different from the hue of. In the case where the compatibility between the binder resin and the fluorescent dye is too low, both are kept separated in the produced heat history display layer 20, and can be kept at a temperature above a specific temperature for a certain period of time. This state is maintained. In this case, since the fluorescent dye molecules are always close to each other, the monomer state cannot be expressed either before or after being held at a temperature equal to or higher than a specific temperature for a predetermined time or longer.

  On the other hand, when the compatibility between the binder resin and the fluorescent dye is too high, the fluorescent dye is completely dissolved in the binder resin, so that depending on the content of the fluorescent dye in the heat history display layer 20, the specific temperature or more is exceeded. The fluorescent dye molecules are separated and dispersed before and after being held at a temperature of a certain time or longer, and the excimer state cannot be expressed.

For example, when the binder resin is a polyester resin (particularly, PET, PETG) or polystyrenes, R ₁ or R ₂ is the number of carbon atoms as the fluorescent dye. The oligophenylene vinylene compound represented by the said formula which is a 15-36 alkoxy group is mentioned. By using these combinations, the compatibility between the polymer and the dye becomes appropriate, and when the dye in the polymer is held for a certain period of time at a temperature above a specific temperature, a hue different from the initial hue It will be discolored.

  The binder resin having appropriate compatibility is preferably a polyester resin. The acid value of the binder resin (polyester resin or the like) is preferably 0.5 to 45 eq / 1t, more preferably 1 to 35 eq / 1t, and most preferably 1 to 30 eq / 1t. When the acid value contained in the polyester resin exceeds 45 eq / 1t, it is irreversibly changed to a hue different from the initial hue even when held at a temperature above a specific temperature for a certain period of time when exposed to ultraviolet rays. It will not discolor and will not function as a heat history indicator. If the acid value is less than 0.5 eq / 1t, the cost increases during production, which tends to be impractical. In addition, an acid value can be measured by the titration using potassium hydroxide like the below-mentioned Example, for example.

  Examples of the method for adjusting the acid value to 0.5 to 45 eq / 1t include a method for adjusting a glycol / dicarboxylic acid molar ratio during polyester synthesis and a method for lowering the thermal history during removal. In adjusting the glycol / dicarboxylic acid molar ratio during polyester synthesis, the glycol / dicarboxylic acid molar ratio is preferably 2.10 to 1.60, more preferably 2.05 to 1.65, and most preferably 2.00. ~ 1.70. If the glycol / dicarboxylic acid molar ratio is less than 1.6, the acid value tends to be high, and if the glycol / dicarboxylic acid molar ratio exceeds 2.1, the production cost increases, so that it tends to be impractical.

  When the heat history display material of the present invention is exposed to ultraviolet rays by constituting the outer resin layer with a resin having ultraviolet absorptivity (for example, left outdoors under a fluorescent lamp, LED, incandescent bulb for a long time). However, it is possible to accurately display the thermal history (temperature-time history) of the article by changing the hue. In this way, the acid value of the binder resin having an appropriate compatibility with the fluorescent dye can be obtained. By controlling, the display accuracy of the thermal history (temperature-time history) can be further increased. In particular, the effect of controlling the acid value of the binder resin is considered to be effective when all the ultraviolet rays cannot be absorbed even if the outer resin layer is given ultraviolet absorption characteristics.

  The content of the fluorescent dye in the heat history display layer 20 is preferably 0.01 to 10% by weight, more preferably 0.5 to 5% by weight with respect to 100% by weight of the binder resin. In such a range, the dye content is within such a range that when the dye in the polymer composition is held for a certain period of time at a temperature above a specific temperature, the polymer and the polymer are changed to a hue different from the initial hue. It is desirable to adjust according to the compatibility of the dye.

  It is preferable that the molecules of the fluorescent dye in the heat history display layer 20 are initially dispersed and fixed in a monomer state. In this case, when the heat history display material is exposed to a specific temperature or more for a predetermined time or more, the dispersed state of the fluorescent dye molecules shifts to the excimer state, and the hue of the fluorescent dye changes.

  The “specific temperature” is preferably a temperature equal to or higher than the glass transition temperature of the heat history display layer 20. Below the glass transition temperature, the fluorescent dye molecules are constrained by the binder resin in a sufficiently spaced and dispersed state, and the dispersion state does not change, but when the glass transition temperature is exceeded, the polymer chains of the binder resin are entangled. As it becomes loose, the movement of the polymer chain increases, this restriction is released, the fluorescent dye molecule becomes movable, an excimer (excited aggregate) is formed, and the hue starts to change (red shift). When the time of exposure to a temperature higher than a specific temperature continues for a certain time or more, the concentration of the excimer (excited aggregate) increases to such a level that it can be clearly distinguished from the hue in the monomer state. Fluorescent dye molecules that have been unconstrained have a large amount of movement at higher temperatures. Therefore, the higher the specific temperature, the more the excimer (excited aggregate) concentration can be clearly distinguished from the hue in the monomer state. The time until it becomes high enough to change is shortened.

  By adjusting the types of fluorescent dyes and binder resins to be used, and their blending ratio, etc., the design of the heat history display material (that is, how much heat history causes the hue change) is made desired. be able to.

  As a method of obtaining the heat history display layer 20 in which the fluorescent dye is dispersed and fixed in the binder resin in the monomer state, for example, the fluorescent dye is mixed and dispersed in the molten binder resin, and water or the like is used during molding. Also, there is a method of solidifying by dispersing rapidly. The temperature at which the fluorescent dye is mixed and dispersed in the binder resin is usually a temperature equal to or higher than the glass transition temperature of the binder resin, preferably from the glass transition temperature (K) to the glass transition temperature (K) × 2.0. More preferably, it is between glass transition temperature (K) × 1.1 and glass transition temperature (K) × 1.7.

  The heat history display layer 20 is not limited to the above-described one in which the fluorescent dye is dispersed and fixed in the binder resin in the monomer state by melt blending, and the fluorescent dye is in the monomer state in the binder resin by other manufacturing methods. For example, the fluorescent dye and the binder resin may be uniformly mixed by a solution blend in which the fluorescent dye and the binder resin are dissolved in a solvent.

  Alternatively, the heat history display layer 20 may be configured by chemically bonding (covalently bonding) a fluorescent dye to a binder resin. According to such a chemical bond type thermal history display layer 20, the hue change rate can be delayed and the possibility that the fluorescent dye bleeds out from the thermal history display layer 20 during use can be eliminated. it can. However, since the chemical bond type heat history display layer 20 tends to require a larger amount of fluorescent dye than the heat history display layer 20 by melt blending in order to cause a hue change, within the above range, It is desirable to increase the content.

  When the fluorescent dye is chemically bonded (covalently bonded) to the binder resin, a reactive substituent capable of reacting with the binder resin is introduced into the fluorescent dye. Specific examples of the reactive substituent include a hydroxyl group, an amino group, a carboxyl group, an acrylic acid group, an acrylate group, an isocyanate group, an epoxy group, cyanate esters, and benzoxazines, and preferably a hydroxyl group.

For example, when the fluorescent dye is an oligophenylene vinylene compound represented by the above formula, a reactive functional group is introduced into one or more substituents of R, R ₁ and R ₂ , or R, R ₁ , Any one or more of R ₂ may be a reactive substituent.

  The binding position of the fluorescent dye in the binder resin is not particularly limited, and the fluorescent dye may be bound to the polymer main chain of the binder resin, or the fluorescent side chain may be fluorescent to control the association of the fluorescent dye. A dye may be bound.

  The type of the binder resin in the chemical bond type is not particularly limited as long as it has a substituent capable of chemically bonding with the fluorescent dye, and can be selected from those exemplified above. Further, when a branched polymer, hyperbranch, dendrimer, cross-linked polymer or the like is used as the binder resin, the mobility of the chemically bonded fluorescent dye is increased, so that the threshold of hue change can be clarified.

  The heat history display layer 20 can contain additives and the like in addition to the fluorescent dye and the binder resin. Specific examples of the additive include an organic, inorganic or organometallic toner, and a fluorescent brightening agent. By including one or more of these, the hue change of the heat history display layer 20 can be further clarified. Specific examples of other additives include polymers other than binder resins, antistatic agents, antifoaming agents, dyeability improvers, dyes other than the above fluorescent dyes, pigments, matting agents, stabilizers, and antioxidants. . As antioxidants, aromatic amines, phenols, and other antioxidants can be used. As stabilizers, phosphoric acid and phosphoric acid esters are used, as well as sulfur and amines. Stabilizers can be used.

  The heat history display layer 20 can be in the form of a film or fiber, preferably in the form of a film. The thickness of the film-like heat history display layer 20 is not particularly limited, but is usually about 10 to 200 μm. Further, the heat history display layer 20 may be a compact having a suitable size by solidifying fine objects such as particles and fine pieces.

(2) Outer resin layer The outer resin layer 10 is a layer disposed on one main surface (upper surface in FIG. 1) of the heat history display layer 20. By disposing the outer resin layer 10 on one main surface of the heat history display layer 20, the main surface can be covered and protected from ultraviolet rays. In the embodiment shown in FIG. 1, the outer resin layer 10 is composed of a translucent resin layer 11 and an adhesive resin layer 12 laminated on the surface on the heat history display layer 20 side. The adhesive resin layer 12 is a layer for adhering the outer resin layer 10 to the heat history display layer 20 (and a base material 30 described later).

  The surface on the outer resin layer 10 side in the heat history display material 1 is the surface on the outermost surface when the heat history display material 1 is attached to an article (surface opposite to the surface to be attached). It is a surface on the side for visually recognizing whether or not a hue change has occurred in the heat history display layer 20. Therefore, it is preferable that the outer resin layer 10 has translucency. That is, it is preferable that the translucent resin layer 11 and the adhesive resin layer 12 have translucency.

  And the outer side resin layer 10 has ultraviolet absorptivity. The ultraviolet transmittance of the outer resin layer 10 is preferably 1.01 to 5%, more preferably 0.05 to 3%. By the outer resin layer 10 having ultraviolet absorptivity, the hue of the heat history display layer 20 is changed regardless of (or approximately) the amount of ultraviolet light irradiated on the article to which the heat history display material 1 is adhered. The thermal history of the article can be displayed stably and accurately. The ultraviolet transmittance can be determined by, for example, the Lambert Bale method. Further, in order for the outer resin layer 10 to have ultraviolet absorptivity, at least one of the translucent resin layer 11 and the adhesive resin layer 12 constituting the outer resin layer 10 only needs to have ultraviolet absorptivity.

  The resin constituting the translucent resin layer 11 having ultraviolet absorptivity is not particularly limited as long as it has ultraviolet absorptivity. For example, a resin composition in which various ultraviolet absorbers are kneaded into a thermoplastic resin. And an ultraviolet absorbent applied to the surface of a film made of a thermoplastic resin.

  Examples of the thermoplastic resin include polyester resins (polyethylene terephthalate (PET), copolymers of PET and 1,4-cyclohexanedimethanol (PETG), polybutylene terephthalate, polyethylene naphthalate, etc.); acrylic resins; Polystyrene resin (polyamide resin (nylon 6, nylon 6.6, nylon 12, nylon 4.6, etc.)); polyolefin resin (polyethylene, polypropylene, etc.); vinyl halide resin (polyvinyl chloride, polyvinylidene chloride, Polyvinyl fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene); cellulose resin; polycarbonate resin; polyacrylonitrile resin. Among these, preferable resins include polyester resins and cellulose resins, and particularly preferable resins include polyethylene terephthalate, polybutylene terephthalate, polynaphthalene terephthalate, and polycarbonate. The translucent resin layer 11 is preferably a film-like member obtained by uniaxially or biaxially stretching these resins.

  There is no restriction | limiting in particular as an ultraviolet absorber, For example, all the ultraviolet absorbers for thermoplastic resins, such as a naphthalene type, a benzophenone type, a benzotriazole type, and a salicylic acid ester type, can be used. Examples of such ultraviolet absorbers include polyethylene naphthalene, naphthalenedicarboxylic acid copolymer polyester, 2-hydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, and 2,2′-. Examples include dihydroxy-4-methoxybenzophenone, 2-hydroxyphenylbenzotriazole, and phenyl salicylate. Of these, polyethylene naphthalene and naphthalene dicarboxylic acid copolyester are preferably used, and polyethylene naphthalene is more preferably used from the viewpoints of heat resistance and water resistance. Moreover, these ultraviolet absorbers can be used individually or in combination of 2 or more types, Furthermore, stabilizers, such as antioxidant and a hindered amine, may be used together. The blending amount when the ultraviolet absorber is blended in the translucent resin layer 11 is preferably about 0.01 to 20% by weight based on the total weight of the translucent resin layer 11.

  Moreover, as resin which comprises the translucent resin layer 11, you may use resin which itself has ultraviolet absorptivity instead of kneading or apply | coating an ultraviolet absorber. Examples of the resin having ultraviolet absorptivity per se include polyethylene naphthalate (PEN) and polyester containing anthracene dicarboxylic acid, pyrene dicarboxylic acid or naphthacene dicarboxylic acid as a dicarboxylic acid component.

  In addition, an opaque resin can be used. However, the translucent resin layer 11 preferably has a predetermined translucency so that the color change of the internal heat history display layer can be visually confirmed. Furthermore, a metal foil may be included as part of the translucent resin layer 11.

  Although the thickness of the translucent resin layer 11 can be set arbitrarily, it is usually preferably about 10 to 200 μm. When the thickness of the translucent resin layer 11 is less than 10 μm, the ultraviolet absorptivity becomes insufficient. On the other hand, when it is thicker than 200 μm, the discoloration of the dye that has received the heat history is lowered, and it becomes difficult to accurately display the heat history and the time elapsed by the product.

  The adhesive resin layer 12 can be a pressure-sensitive adhesive layer composed of an acrylic, silicone-based, urethane-based or rubber-based pressure-sensitive adhesive, or can be an adhesive layer composed of an adhesive. The adhesive resin layer 12 may be provided with ultraviolet absorptivity. For example, the above-described ultraviolet absorber is kneaded into the resin constituting the adhesive resin layer 12, or the resin itself has ultraviolet absorptivity. May be used. The thickness of the adhesive resin layer 12 is usually about 0.05 to 5 μm.

  In the embodiment shown in FIG. 1, the outer resin layer 10 is attached to one surface of the heat history display layer 20 (the surface that is the outermost surface when the heat history display material 1 is attached to an article (attachment). The surface on the side opposite to the surface to be applied)) is provided only on the side, but the surface on the side to be attached to the article of the heat history display layer 20 may be irradiated with ultraviolet rays (for example, heat In the case where the article to which the history display material 1 is attached is an ultraviolet transmissive resin container or the like, it is preferable to provide an outer resin layer on the side of the heat history display layer 20 attached to the article. In this case, an outer resin layer may be provided instead of the organic thin film layer 40 (omitting the organic thin film layer 40), and between the organic thin film layer 40 and the heat history display layer 20 or the heat of the organic thin film layer 40. An outer resin layer may be provided on the side opposite to the history display layer 20 (aside from the organic thin film layer 40). Further, the outer resin layer may be provided so as to seal the entire predetermined portion including the heat history display layer 20.

  In the embodiment shown in FIG. 1, the outer resin layer 10 is provided on the outermost surface of the heat history display material 1, but is not necessarily provided on the outermost surface. An outer resin layer may be provided as an arbitrary layer between the heat history display layer 20.

  In the embodiment shown in FIG. 1, the outer resin layer 10 is provided so as to cover not only the heat history display layer 20 but also one surface of the substrate 30, but the outer resin layer is at least a heat history display layer. 20 need only be provided so as to cover 20, and need not necessarily be provided so as to cover the base material 30.

(3) Organic thin film layer The organic thin film layer 40 is a layer disposed on the other main surface (the lower surface in FIG. 1) of the thermal history display layer 20. By disposing the organic thin film layer 40 on the other main surface of the heat history display layer 20, the main surface can be covered and protected. In addition, the organic thin film layer 40 protects an article having a heat history display material attached thereto from such an eluate in preparation for a situation in which a part of the components of the heat history display layer 20 is eluted by heat. Also plays a role.

  Although the material which comprises the organic thin film layer 40 is not restrict | limited in particular, For example, a polyethylene terephthalate, polyethylene, a polypropylene, and polylactic acid can be mentioned.

(4) Base Material In the embodiment shown in FIG. 1, the base material 30 is a layer for covering and protecting all the sides of the heat history display layer 20. In addition to the outer resin layer 10 and the like, it also plays a role of securing an appropriate rigidity of the heat history display material 1 as a label used for sticking to an article. As in the embodiment shown in FIG. 1, all the surfaces of the heat history display layer 20 are covered (sealed) with a plurality of coating layers. The function of stably and accurately displaying the heat history of the article by changing the hue is preferable for ensuring long-term sustainability.

  In the embodiment shown in FIG. 1, referring to FIG. 2, a layer that penetrates in the thickness direction and has a through-hole 32 having the same shape as that of the heat history display layer 20 at the center is used as the base material 30. By embedding the heat history display layer 20 in the mouth 32, all sides of the heat history display layer 20 are covered. The shape of the through-hole 32 is not particularly limited, and may be a shape corresponding to the outer shape of the heat history display layer 20.

  The material constituting the base material 30 can be selected, for example, from the thermoplastic resins exemplified above for the outer resin layer 10, but selecting a material having ultraviolet absorptivity increases the thermal history of the article. This is advantageous for accurate display. In the embodiment shown in FIG. 1, the thickness of the base material 30 can be the same as or approximately the same as the thickness of the heat history display layer 20.

  In the embodiment shown in FIG. 1, an adhesive resin layer 31 is laminated on the surface of the base material 30 on the organic thin film layer 40 side. The adhesive resin layer 31 is a layer for attaching the base material 30 to the organic thin film layer 40. The configuration, material, and thickness of the adhesive resin layer 31 can be the same as those of the adhesive resin layer 12.

  In the present invention, the substrate 30 can be omitted. In this case, in order to cover (seal) all the surfaces of the heat history display layer 20, it is preferable to join all sides (all end portions) of the outer resin layer 10 and the organic thin film layer 40. At this time, depending on circumstances, at least one of the adhesive resin layer 12 of the outer resin layer 10 and the adhesive resin layer 31 of the base material 30 may be omitted.

(5) Outermost Adhesive Resin Layer The adhesive resin layer 50 is a layer that is optionally provided as necessary, and is a layer for adhering the heat history display material 1 to an article. The adhesive resin layer 50 is provided on the outermost surface of the heat history display layer 20 opposite to the outer resin layer 10. By providing the adhesive resin layer 50, the heat history display material 1 can be used as a seal-type label.

  The configuration, material, and thickness of the adhesive resin layer 50 can be the same as those of the adhesive resin layer 12.

(6) Other components The heat history display material of the present invention can include a support layer laminated on the outer surface of the adhesive resin layer 50 in order to increase its rigidity. As a material of the support layer, for example, a thermoplastic resin exemplified as a material constituting the outer resin layer 10 can be used. When a support layer is included, an adhesive resin layer for adhering the heat history display material 1 to an article may be further laminated on the outer surface (the outermost surface of the heat history display layer opposite to the outer resin layer). it can.

  Further, when an adhesive resin layer (adhesive resin layer 50 or another adhesive resin layer) is laminated on the outermost surface of the heat history display material 1 that is attached to the article, the outer surface of the adhesive resin layer Further, it is preferable to laminate a peelable layer (peeling layer) for protecting the surface of the adhesive resin layer. This release layer is usually laminated until sticking to an article and peeled off when sticking. As the release layer, a release paper or the like can be used in addition to the polyester resin film and the polyolefin resin film.

  According to the heat history display material (label) of the present invention, by sticking this to an article, the article is not less than a specific temperature regardless of (or approximately) the amount of ultraviolet irradiation to the article. It is possible to accurately and easily determine whether or not the temperature has been maintained for a certain time or more by the hue change of the heat history display layer. Moreover, since the heat history display material of this invention has a simple structure, it can be manufactured easily and advantageously in terms of manufacturing cost.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not limited to these. In the following examples and comparative examples, the solution viscosity of the polyester resin (reduced viscosity ηsp / c (dl / g)), the composition ratio of the polyester resin, the glass transition temperature of the polyester resin, and the acid value of the polyester resin, In addition, the weather resistance test was performed according to the following method.

(1) Solution viscosity of polyester resin (reduced viscosity ηsp / c (dl / g))
0.1 g of polyester resin was precisely weighed and dissolved in 25 mL of a mixed solvent of phenol / tetrachloroethane (mass ratio 3/2), and then measured at 30 ° C. using an Ostwald viscometer.

(2) Composition ratio of polyester resin About 5 mg of polyester resin is dissolved in 0.7 mL of a mixed solvent of deuterated chloroform and trifluoroacetic acid (volume ratio 9/1), and ¹ H-NMR (manufactured by varian, UNITY 50) is used. And asked.

(3) Glass transition temperature of polyester resin Measured with a high-sensitivity differential scanning calorimeter (DSC) (model: EXSTAR DSC7020) manufactured by Hitachi High-Tech Science Co., Ltd. under a nitrogen gas atmosphere at a heating rate of 10 ° C./min. did.

(4) Acid value of polyester resin (eq / 1t)
1.0 g of the sample was precisely weighed and dissolved in 20 mL of chloroform. Subsequently, it titrated with 0.01N potassium hydroxide (ethanol solution). As the indicator, phenolphthalein was used.

(5) Method for Measuring Ultraviolet Transmittance Using a spectrophotometer “U-3500” (manufactured by Hitachi, Ltd.), the transmittance in the wavelength range of 320 to 360 nm was determined.

(6) Weather resistance test The weather resistance test was conducted using an accelerated weather resistance tester QUV (manufactured by Q-Panel). In addition, after being held at 35 ° C. for 2 hours while being irradiated with UV, a test of 100 cycles was carried out with a total of 10 hours of tests held at 30 ° C. for 8 hours under humidity conditions where UV irradiation was not performed and dew condensation was taken as one cycle. .

<Example 1>
According to the following procedure, the heat history display material having the configuration shown in FIG. 1 was produced.

(1) Production of thermal history display layer (Heat history display layer A)
In a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser and a distillation tube, ethylene glycol and propylene glycol as glycol components, terephthalic acid as dicarboxylic acid components, and a molar ratio of glycol component / dicarboxylic acid component of 2.0. Furthermore, 0.3 mol part of triethylamine is charged with respect to 200 mol parts of the monomer component (total of glycol component and dicarboxylic acid component), and 250 ° C. in a nitrogen atmosphere and 2 atm for 5 hours. The esterification reaction was carried out while gradually elevating the temperature until the distilled water was removed from the system. Subsequently, after returning to normal pressure, 0.05 mol part of germanium dioxide was added to 200 mol parts of the monomer component, and the mixture was stirred for 5 minutes, then subjected to reduced pressure initial polymerization to 10 mmHg over 30 minutes and the temperature was adjusted to 250 ° C. Then, the polymerization was further performed at a rate of 1 mmHg or less for 60 minutes to obtain a copolyester resin A.

  Copolymerized polyester resin (binder resin) A had a glass transition temperature of 78 ° C., a reduced viscosity of 0.7, and an acid value of 21 eq / 1 t. The composition ratio was terephthalic acid / ethylene glycol / propylene glycol = 100/40/60 in terms of molar ratio.

Then, after remelting the obtained copolyester resin, a C18RG dye (oligophenylene vinylene) in which R is hydrogen, R ₁ is an octadecyloxy group (C ₁₈ H ₃₇ O—), and R ₂ is a methoxy group in the above formula. Compound) was added to the copolymerized polyester resin by 1.3% by weight and melt blended for 10 minutes to obtain a polymer composition in which the dye was uniformly dispersed in the copolymerized polyester resin. The obtained polymer composition was heated and pressed at 230 ° C., and then rapidly cooled with cold water to obtain a cylindrical heat history display layer 20 (heat history display layer A) having a thickness of 50 μm and a diameter of about 2 cm. The heat history display layer A was yellow.

(2) Production of outer resin layer (outer resin layer A)
A biaxially stretched polyethylene terephthalate (PET) film having a thickness of 50 μm containing 0.3% by weight of an ultraviolet absorber [“ADEKA STAB LA36” manufactured by ADEKA Co., Ltd.] is prepared as the translucent resin layer 11. An acrylic pressure-sensitive adhesive (“SK Dyne 701” manufactured by Soken Chemical Co., Ltd.) was applied on a gravure roll coater so that the thickness after drying was about 1.5 μm, and dried at 60 ° C. for 10 seconds. Layer 12 was formed. Subsequently, release paper was bonded to the outer surface of the pressure-sensitive adhesive layer, and then cut out into a size of 3 cm in length and 3 cm in width to produce an outer resin layer 10 (outer resin layer A) having a pressure-sensitive adhesive layer. In addition, the outer side resin layer A has ultraviolet absorptivity by blending an ultraviolet absorber (ultraviolet transmittance: 0.01%).

(3) Fabrication of base material As the base material 30, a 50 μm-thick void-containing polyester film (“Chrisper K7911” manufactured by Toyobo Co., Ltd.) was prepared, and an acrylic pressure-sensitive adhesive [manufactured by Soken Chemical Co., Ltd. “SK Dyne” 701 "] was applied with a gravure roll coater so that the thickness after drying was about 1.5 μm, and dried at 60 ° C. for 10 seconds to form an adhesive layer 31. Next, after attaching release paper to the outer surface of the pressure-sensitive adhesive layer 31, a through-hole having a diameter of about 2 cm that penetrates the base material 30, the pressure-sensitive adhesive layer 31 and the release paper in the thickness direction is provided. The base material 30 which cut out to the size of 3 cm long x 3 cm wide so that it may be located, and has the adhesive layer 31 was produced.

(4) Preparation of organic thin film layer As the organic thin film layer 40, an acrylic pressure-sensitive adhesive was prepared on a biaxially stretched PET film having a thickness of 50 μm, and an acrylic pressure-sensitive adhesive [manufactured by Soken Chemical Co., Ltd. “SK Dyne” was prepared. 701 "] was applied with a gravure roll coater so that the thickness after drying was about 1.5 μm, and dried at 60 ° C. for 10 seconds to form an adhesive layer 50. Next, 51 release papers were bonded to the outer surface of the pressure-sensitive adhesive layer 50, and then cut into a size of 3 cm in length × 3 cm in width to produce an organic thin film layer 40 having the pressure-sensitive adhesive layer 50.

(5) Production of heat history display material The organic thin film layer 40 with the pressure-sensitive adhesive layer 50 (with the release paper 51 attached) was placed so that the release paper 51 was on the lower side. Next, the base material 30 with the pressure-sensitive adhesive layer 31 from which the release paper has been peeled is overlapped with the organic thin-film layer 40 so that the pressure-sensitive adhesive layer 31 is on the lower side. Pasted on. Thereafter, the heat history display layer 20 (heat history display layer A) was embedded in the through-hole 32 of the base material 30. Subsequently, the outer side resin layer 10 (outer side resin layer A) which consists of the translucent resin layer 11 with the adhesive layer 12 which peeled release paper is used for the base material 30 (and so that the adhesive layer 12 may become a lower side. The heat history display layer 20) was overlapped with the ends thereof and attached to the heat history display layer 20 and the substrate 30. Thus, the heat history display material (Example 1) which contains the adhesive resin layer (adhesive layer) 50 in the outermost surface on the opposite side to the outer side resin layer 10 of the heat history display layer 20 was obtained.

<Example 2>
A heat history display material (Example 2) was obtained in the same manner as in Example 1 except that the following outer resin layer B was used instead of the outer resin layer A.

(Outside resin layer B)
A biaxially stretched PET film having a thickness of 50 μm containing 3% by weight of polyethylene naphthalate (PEN) resin is prepared as the translucent resin layer 11, and an acrylic pressure-sensitive adhesive [manufactured by Soken Chemical Co., Ltd. “ SK Dyne 701 "] was applied with a gravure roll coater so that the thickness after drying was about 1.5 μm, and dried at 60 ° C. for 10 seconds to form an adhesive layer 12. Subsequently, release paper was bonded to the outer surface of the pressure-sensitive adhesive layer 12, and then cut into a size of 3 cm in length and 3 cm in width to produce an outer resin layer 10 (outer resin layer B) having the pressure-sensitive adhesive layer 12. In addition, this outer side resin layer B has ultraviolet absorptivity by mix | blending PEN resin (ultraviolet transmittance: 0.08%).

<Example 3>
A heat history display material (Example 3) was produced in the same manner as in Example 1 except that the following outer resin layer C was used instead of the outer resin layer A.

(Outside resin layer C)
A biaxially stretched PEN film having a thickness of 50 μm is prepared as the translucent resin layer 11, and an acrylic adhesive (“SK Dyne 701” manufactured by Soken Chemical Co., Ltd.) is dried on one side thereof to a thickness of about 1 The pressure-sensitive adhesive layer 12 was formed by coating with a gravure roll coater to a thickness of 5 μm and drying at 60 ° C. for 10 seconds. Subsequently, release paper was bonded to the outer surface of the pressure-sensitive adhesive layer 12, and then cut into a size of 3 cm in length and 3 cm in width to produce an outer resin layer 10 (outer resin layer C) having the pressure-sensitive adhesive layer 12. Since the outer resin layer C is a PEN film, it has ultraviolet absorptivity (ultraviolet transmittance: 0.05%).

<Example 4>
A heat history display material (Example 4) was produced in the same manner as in Example 1 except that the following heat history display layer B was used instead of the heat history display layer A.

(Heat history display layer B)
A copolyester resin B was obtained in the same manner as in the production of the copolyester resin A, except that charging was performed so that the molar ratio of recall / dicarboxylic acid was 1.1.

  Copolymerized polyester resin (binder resin) B had a glass transition temperature of 78 ° C., a reduced viscosity of 0.7, and an acid value of 42 eq / 1 t. The composition ratio was terephthalic acid / ethylene glycol / propylene glycol = 100/40/60 in terms of molar ratio.

  Thereafter, the heat history display layer B was obtained in the same manner as the heat history display layer A by using the copolyester resin B.

<Comparative Example 1>
A heat history display material (Comparative Example 1) was produced in the same manner as in Example 1 except that the following outer resin layer D was used instead of the outer resin layer A.

(Outside resin layer D)
A biaxially stretched PET film having a thickness of 50 μm is prepared as the translucent resin layer 11, and an acrylic pressure-sensitive adhesive (“SK Dyne 701” manufactured by Soken Chemical Co., Ltd.) is dried on one side thereof to a thickness of about 1 The pressure-sensitive adhesive layer 12 was formed by coating with a gravure roll coater to a thickness of 5 μm and drying at 60 ° C. for 10 seconds. Subsequently, release paper was bonded to the outer surface of the pressure-sensitive adhesive layer 12, and then cut out into a size of 3 cm in length and 3 cm in width to produce an outer resin layer 10 (outer resin layer D) having the pressure-sensitive adhesive layer 12. In addition, since the outer side resin layer D is a PET film, it has substantially no ultraviolet absorptivity (ultraviolet transmittance: 75.6%).

[Evaluation test]
The accelerated weather resistance test was performed on the heat history display materials obtained in Examples 1 to 4 and Comparative Example 1. After sticking the heat history display material to the can body of the beverage can, the beverage can was stored in a thermostatic chamber at 90 ° C. for 40 minutes, and the discoloration state was observed.

  And, when 30 minutes have passed since the start of storage in the thermostat, when the heat history display material has changed from yellow to orange, "1", at the time when 30 minutes have passed after the start of storage in the thermostat, When the heat history display material remains yellow and 40 minutes have passed since the start of storage, the heat history display material has changed from yellow to orange when “2”, and when 40 minutes have passed since the start of storage. The evaluation was performed in three stages, with the case where the heat history display material remained yellow as “3”. The evaluation results are shown in Table 1.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Thermal history display material, 10 Outer resin layer, 11 Translucent resin layer, 12, 31, 50 Adhesive resin layer (adhesive layer), 51 Release paper, 20 Thermal history display layer, 30 Base material, 32 Through-hole 40 Organic thin film layer.

Claims (8)

An associative fluorescent dye having a fluorescence wavelength different between an excimer state and a monomer state includes a heat history display layer fixed in a specific molecular dispersion state;
On at least one surface side of the thermal history display layer, seen containing an outer resin layer having a UV absorbing,
The heat history display layer contains a binder resin and the fluorescent dye dispersed in the binder resin,
The heat history display material whose acid value of the said binder resin is 0.5-45 eq / 1t . Further comprises a substrate, the thermal history display material according to claim 1. The base material has a through-hole penetrating in the thickness direction,
The heat history display material according to claim 2 , wherein the heat history display layer is embedded in the through hole. Furthermore, the heat history display material of any one of Claims 1-3 which contains an organic thin film layer on the opposite side to the said outer side resin layer of the said heat history display layer. Furthermore, the heat history display material of any one of Claims 1-4 which contains an adhesive resin layer in the outermost surface on the opposite side to the said outer side resin layer of the said heat history display layer. The heat history display material according to any one of claims 1 to 5 , wherein in the heat history display layer, molecules of the fluorescent dye are fixed in a monomer state. The fluorescent dye has the following formula:

(In the formula, each R independently represents hydrogen, an alkyl group having 1 to 36 carbon atoms, an alkoxy group having 1 to 36 carbon atoms, a hydroxyl group, a hydroxyalkyl group, a halogen group, a phenylene vinylene group or a cyano group.
Each R1 independently represents hydrogen, an alkyl group having 1 to 36 carbon atoms, an alkoxy group having 1 to 36 carbon atoms, a hydroxyl group, a hydroxyalkyl group, a halogen group, a phenylene vinylene group or a cyano group;
R2 independently represents hydrogen, an alkyl group having 1 to 36 carbon atoms, an alkoxy group having 1 to 36 carbon atoms, a hydroxyl group, a hydroxyalkyl group, a halogen group, a phenylene vinylene group or a cyano group. )
The heat history display material according to any one of claims 1 to 6 , which is an oligophenylene vinylene compound represented by: The heat history display material with a peeling layer containing the heat history display material of Claim 5 , and the peeling layer laminated | stacked on the surface on the opposite side to the said outer side resin layer of the said adhesive resin layer.

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