JPH0339623B2 - - Google Patents

Description

[Detailed description of the invention]

Purpose of the invention This invention provides food that should be stored below a predetermined temperature,
The present invention relates to a material for a temperature/time display label that detects when a medicine or the like is left at a predetermined temperature or higher. "Industrial Application Fields and Conventional Technology" Conventionally, the capillary action of permeable materials has been used as an indicator to know the history of chemicals stored in a cool, dark place or foods that should be stored in a cold place being left at a temperature higher than a specified temperature. The thing is known (for example, Japanese Patent Publication No. 1989-1999)
No. 60262). These consist of a white permeable material such as filter paper, a colored liquid, and a porous matrix or colored liquid reservoir that supports the colored liquid, where the colored liquid is solid or semi-solid below a certain temperature and becomes liquid above a certain temperature. Permeation starts upon contact with the permeable material, and by observing the permeation area, it is possible to detect whether the temperature has been left at a predetermined temperature or higher and the length of time the material has been left unused. In addition, a colorless color former is contained in the liquid, and another color developer is provided at a specific point of the permeable material, so that when the liquid moves through the permeable material and touches the color developer, it reacts. Some are colored. ``Problem to be solved by the invention'' However, food, medicine, and other products to which these temperature and history display devices are attached often have colors, so even if the display device is colored, visual confusion may occur. There were many cases where this was overlooked. Therefore, depending on the type of product to be affixed, a display device is required that allows the viewer to detect abnormalities by coloring the display of the permeable material and then erasing the color. The present inventor aims to provide a material for temperature and time display labels used in such display devices,
The present invention was completed by utilizing coloring technology and decoloring technology from other technical fields, such as pressure-sensitive recording paper and heat-sensitive recording paper, and by using a specific pigment-coated paper as a permeable material. Structure of the Invention According to the present invention, the main parts are a detection agent having a melting point corresponding to a predetermined temperature and a permeable material, and the area where the detecting agent, which becomes liquid at a temperature higher than the predetermined temperature, has permeated into the permeable material is displayed by a change in hue. In the temperature history display device, the detecting agent is composed of the above-mentioned detecting agent and a permeable material having a colored layer on the surface, and the detecting agent is singly or a mixture of desensitizing higher alcohols having 6 or more carbon atoms, and the above-mentioned colored layer is a layer made of a colored material made by coloring a colorless dye with a color developer, and a material for a temperature/time display label is provided in which a region that has been decolored by a reaction between a detection agent and the colored material is displayed. "Means for Solving the Problems" The present invention will be explained below by dividing it into a detection agent, a permeable material, and a colored layer. The detection agent used in the present invention is a desensitizing higher alcohol having 6 or more carbon atoms, singly or as a mixture, and has a melting point corresponding to the temperature specified by the present invention (hereinafter referred to as predetermined temperature). Here, the melting point corresponding to the predetermined temperature includes the temperature at which the detection agent melts and starts permeating into the permeable material. Alcohols having 6 or less carbon atoms are volatile and have a strong odor, making them unsuitable for the purpose of the present invention.
Further, in the present invention, since pigment-coated paper mainly composed of cellulose fibers is suitable as the permeable material, higher alcohols that do not swell these constituent fibers are suitable. Furthermore, it is possible to select or mix products with melting points that suit specific temperatures, especially those with sharp melting points, from extremely low temperatures to high temperatures. Since it can also be used as a material, it has the advantage of being safe. Examples of higher alcohols include the following.
The value in parentheses indicates the melting point in °C. As saturated primary alcohols, hexanol (-44.6℃), heptanol (-34.0), octanol (-14.9), nonanol (-5.0), decanol (+6.9), undecanol (+15.9), dodecanol (+24.0) , tridecanol (+30.6), tetradecanol (+37.9), pentadecanol (+43.9), hexadecanol (+49.3), heptadecanol (+53.9), octadecanol (+58. 0), nonadecanol (+
61.7), eicosanol (+65.5). Saturated secondary alcohols include octanol-2 (-31.6°C), nonanol-2 (-35), decanol-2 (-2.4),
Undecanol-2 (0), Dodecanol-2 (+
5), tridecanol-2 (+17), pentadecanol-2 (+27), hexadecanol-2 (+44),
heptadecanol-2 (+44.5), octadecanol-2 (+47), nonadecanol-2 (+49), eicosanol-2 (+50.7). Examples of unsaturated alcohols include 10-undecenol-1 (-2℃), 12-tridecenol (+15), and oleyl alcohol (+
2), elaidyl alcohol (+36-37), linoleyl alcohol (-16), linolenyl alcohol, etc. can be used, and in addition to these, alcohols having side chains such as 2-hexyldecyl alcohol, 14-
Higher diols contained in methylhexadecanol-1, wool fat, etc. can also be used. Desensitization will be specifically explained in the section on colored layers. The permeable material used in the present invention is paper mainly made of cellulose fibers, and pigment-coated paper is preferably used, with the desired liquid permeation rate being adjusted by adjusting the degree of beating of the raw material. In general, regarding liquid movement within capillaries, The following relationships are known: h: moving distance of the liquid, γ: indicated tension of the liquid, η: viscosity of the liquid, r: radius of the capillary, θ: contact angle of the liquid with the surface of the capillary, and t: permeation time. When the temperature is constant and the capillary tube and liquid are a certain combination, it can be simplified as h=k√, and the permeation distance of the liquid is √
It will be proportional to. Therefore, the permeation time can be determined from the liquid permeation distance. Also, if the liquid is kept below a predetermined temperature and solidifies, seepage will stop. As shown in the above equation, the square root of the capillary diameter is proportional to the moving distance of the liquid, so the permeation rate of the liquid depends on the degree of beating of the permeable material, and the capillary diameter can be adjusted over a wide range. Pigment-coated paper is used because the colored layer has a beautiful finish and the contrast between the hues before and after the liquid bleeds through and fades is vivid. The base paper for the pigment-coated paper is preferably a high-quality paper mainly composed of cellulose fibers in order to achieve the above-mentioned effects. Depending on the purpose, a white pigment commonly used in paper manufacturing may be mixed with synthetic pulp, synthetic fibers, recycled fibers, etc. that do not swell with the detection agent. Its freeness ranges from 100 to 600 Canadian Standard Freeness (CSF), and 300 to 400 CSF is usually used. If it is less than 100, the permeable material is dense, so the permeation rate is slow and it is difficult to observe the difference in permeation time. Moreover, if it exceeds 600, it will become too coarse, causing non-uniformity in the penetration distance, and similarly, it will be difficult to judge the difference in penetration time. Pigment coating may be done on both sides or on one side, but it is preferable for the reasons mentioned above to provide the colored layer on the coated side. Although there are no restrictions on the method of applying the pigment, it is usually applied by an aqueous clay coating method using a known white pigment. Known natural and synthetic binders are used as the binder for this water-based paint, but those with relatively weak film-forming properties and good liquid permeability are preferred. For example, oxidized starch, casein,
Examples include sodium alginate, polyvinyl alcohol, and acrylic latex. The mixing ratio of pigment and binder is based on the solid content weight ratio from the above point of view.
Can be used in the range of 100:10~40 100:15~
30 is preferred. Waterproofing agents and other ingredients may be used to the extent that they do not impede the purpose of the present invention. The amount of water-based paint to be applied may be the same as that for ordinary coated paper, for example, 3 to 10 g/m ² on one side. The colored layer is a layer made of a colored material that disappears when it comes into contact with a liquid sensing agent. Colorless dyes used for pressure-sensitive or heat-sensitive recording paper can be exemplified as raw materials for such colored materials. When a colored product obtained by developing color from this colorless dye with a color developer comes into contact with a higher alcohol liquid having desensitization properties, the color is completely erased. The detection agent used in the present invention is selected from the above desensitizing higher alcohols, and when this is combined with a permeable material having a colored layer made of the above colored substance, the permeable area is decolorized. It can be recognized as a change due to Colorless dyes include triphenylmethane phthalide, fluoran,
indolyl phthalide series, rhodamine lactam series,
Colorless dyes belonging to the naphtolactam, triazene, and hydroxyphthalane systems are used, and triphenylmethane phthalide and fluoran dyes are particularly suitable. As the color developer, organic phenol type, carboxylic acid type, etc. are used. The colored material obtained from these is applied as a paint to the surface of the permeable material together with a lower alcohol-soluble binder. When this colored layer is provided on a white permeable material, the permeable area of the sensing liquid changes to colorless, and when the permeable material has a hue different from the colored material, it represents the hue of the permeable material. Effects of the Invention Next, the effects of the present invention will be explained with reference to experimental examples. Four types of detection agents were made, each with a predetermined temperature of +10°C, +5°C, 0°C, and -15°C. Its composition is shown in Table 1.

[Table] The permeable material was made from double-sided coated paper with a basis weight of 104 g/m ² as follows. Paper is made from 100% hardwood bleached kraft pulp (LBKP) with a freeness of 100 to 600 CSF, and 7 g/m of water-based white pigment is applied to both sides of the supercalendered base paper with a basis weight of 90 g/m ² .
A coated paper with a basis weight of 104 g/m ² was obtained by coating 2 m ² each.
Water-based white pigment contains 100 parts of kaolin and 18 parts of oxidized starch.
parts (each part by weight of solid content).
Preliminary experiments using the above-mentioned detecting agent and permeable material revealed that the detecting agent sharply solidifies and melts at each predetermined temperature, and begins to permeate when the predetermined temperature is exceeded by 1 to 2 degrees Celsius. , if the temperature is kept at or below a certain temperature during the process, seepage will completely stop, and if the same detection agent is used,
It was found that the seepage time and seepage distance can be controlled by changing the degree of beating of the seepage material. Next, fluoran colorless dye PSD-HR (trade name,
(manufactured by Nippon Soka Chemical Co., Ltd.) 1.0 parts, color developer paraphenylphenol resin (manufactured by Gunei Chemical Co., Ltd.) 6.0 parts, ethyl cellulose 3.0 parts (all parts by weight) in acetone,
Dissolve in a 20:20 mixture of toluene and determine the freeness.
A red colored layer was obtained by coating 3 g/m ² on one side of the above permeable material of 400 CSF. Next, 0.02 g of each of the four types of detection agents mentioned above was packed into a 75 μm thick polyethylene film pouch and heat-sealed, and the pouch was attached to one end of the colored layer of the permeable material, which was made into a label shape with a width of 7 mm and a length of 40 mm. Fixed. After leaving this in a room at 20°C, the pouch was pressurized to start seepage. The non-permeable area was red, and the permeable area that came into contact with the detection agent was immediately erased, giving a clear contrast. The results of measuring the permeation time (hr) and permeation distance for each of the four types of detection agents are listed in Table 2, and a diagram of the square root scale is attached. The four straight lines in the figure are A; for +10℃;
B: for 0°C, c: for −15°C, and d: for +5°C.

[Table] From Table 2 and the figure, each detection agent has a different melting point depending on the predetermined temperature, but room temperature (20
℃), it starts to seep through, and in both cases it can be seen that the seepage area expands linearly with respect to the square root of the seepage time. The boundary between the red region and the decolorized region formed a gentle curve, but was clearly demarcated. If the storage temperature is low, for example, use the label material of the present invention for 10℃.
When left at 15℃, the permeation distance corresponding to the permeation time becomes relatively short, making it difficult to read the relationship between the permeation time and the permeation time. It is possible to extend the permeation distance corresponding to each time and make it easier to read. If a temperature display device indicating the number of days of storage is required, this can be done by lowering the degree of beating of the permeable material to 100 to 200 CSF, contrary to the above. Example 1 A black label material of the present invention for use at 5°C was produced.
As the permeable material, SK double-sided coated paper (manufactured by Sanyo Kokusaku Pulp) with a basis weight of 127.9 g/m ² was used. The freeness of this coated paper was 450 CSF. 0.5 parts of fluoran colorless dye PSD-150 (trade name, manufactured by Nisso Chemical Co., Ltd.), 3.0 parts of PPP-R (paraphenylphenol resin, manufactured by Gunei Chemical Co., Ltd.) as a color developer,
A black solution was prepared by mixing 3.0 parts of ethyl cellulose as a binder and dissolving this in a mixed solution of 20 parts of acetone and 20 parts of toluene. This was coated at 3.5 g/m ² on one side of the coated paper. As a detection agent, a mixture of 73 parts of oleyl alcohol and 27 parts of tetradecanol was prepared at 5° C., and the mixture was placed in a polyethylene pouch and heat-sealed, as in the experimental example, and fixed to one end of the black layer of the permeable material. A temperature display device was made by wrapping the label material of the present invention in a transparent exterior film. This at 5℃
When the product was immersed in a transparent liquid product to be kept as described below and the temperature was gradually raised, leaching started at 6°C, the black color of the label material disappeared, and the leaching area was observed to expand. Note that this permeation was stopped by returning the temperature to 5°C. Example 2 A green label material of the present invention for use at 0°C was produced.
Except for using fluoran-based PSD-G (trade name, manufactured by Nisso Chemical Co., Ltd.) as a colorless dye, the developer, binder, and solvent were all the same as in Example 1 and used in the same proportions. It was applied to the see-through material of No. 1 to provide a colored layer with an edge color. A mixture of 80 parts of oleyl alcohol and 20 parts of tetradecanol was used as the detection agent, and a temperature display label was prepared in the same manner as in Example 1 by combining these. This could be fully used for frozen foods. Example 3 A blue label material of the present invention for -15°C was produced. A blue solution was prepared using the same color developer, binder, and solvent as in Example 1 in the same proportions, except that crystal violet lactone (manufactured by Nippon Soka Chemical Co., Ltd.) was used as a colorless dye. The permeable material was prepared in the experimental example with a freeness of 500 CSF, and the above blue solution was applied to it to form a blue colored layer. The detection agent is 35 parts of oleyl alcohol, 2-
Using a mixture of 65 parts of hexyldecyl alcohol,
A temperature display label was made by combining these in the same manner as in Example 1. It was applied to the body of fish such as tuna and bonito, for which temperature is important, and could be effectively used to detect temperature changes during freezing, transportation, and storage. Example 4 The back side of the coated paper with a basis weight of 104 g/m ² used in the experimental example was dyed with a normal water-based red paint, and the surface of the coated paper was coated with the colorless dye used in Example 3, the color developer, A permeable material having a blue layer on the surface and a red layer on the back was prepared by applying a solvent paint consisting of a binder. The detecting agent was the 0°C higher alcohol used in Example 2, and a temperature display device was made in the same manner as in Example 1 using these. In this case, when the temperature reached 0° C. or higher, the blue color in the permeable area disappeared, and at the same time, the permeable material became transparent, and the entire color became red. One such aspect of the present invention is that the hue of the product to be applied is
It is effective when the hue of the bleached area is powdery.

[Brief explanation of the drawing]

The figure is a square root scale diagram showing the relationship between permeation time (hr) and permeation distance at 20°C for four types of detection agents with different melting points. A is for +10°C, B is for 0°C, and C is for -15°C. and d are for +5°C.

Claims (1)

[Scope of Claims] 1. The detection agent having a melting point corresponding to a predetermined temperature and a permeable material are the main parts, and the area where the detecting agent, which becomes liquid at a temperature higher than the predetermined temperature, has permeated into the permeable material is determined by a change in hue. In the temperature history display device that displays,
The detecting agent is composed of the above detecting agent and a permeable material having a colored layer on the surface, and the detecting agent is a desensitizing higher alcohol having 6 or more carbon atoms alone or as a mixture, and the above colored layer is a colorless dye and a color developer. 1. A material for a temperature/time display label, characterized in that the layer is made of a colored material developed by the above method, and a region that has been decolored by a reaction between a detection agent and the colored material is displayed. 2. The temperature/time display label material according to claim 1, wherein the seepage material is pigment-coated paper. 3. The temperature/time display label material according to claim 1 or 2, wherein the base paper of the permeable material is adjusted to have a freeness of 100 to 600 Canadian standard freeness.