JPH0449917B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a time indicator, and is particularly applicable to products with a limited shelf life, such as fragrances, deodorizers, and insect repellents, to determine whether the product is within its shelf life or not. Concerning a time elapsed indicator that allows you to know at a glance. <Prior Art> The present inventors have been conducting trial production of time-lapse indicators that change color, for example, due to oxygen gas, carbon dioxide gas, or nitrogen oxide gas in the atmosphere. However, all of these require storage without contact with air before use, and this has not always been possible to achieve satisfactorily. <Problems to be Solved by the Invention> The present invention makes it possible to measure the effective period of products such as insect repellents, fragrances, and deodorants, that is, periods ranging from several months to several years, and moreover, The objective is to provide a time-lapse indicator in which the reaction does not start until after the reaction has started. <Means for Solving the Problems> In order to achieve the above-mentioned object, the present invention laminates aluminum foil on one side of a transparent synthetic resin film, and partially shapes the aluminum foil surface into shapes such as letters and figures. After applying anti-corrosion treatment to the untreated area, a water-absorbing material is layered to cover the entire surface of the untreated area, and a heat seal lacquer is applied around the water-absorbing material to create a time indicator. This indicator is started by applying a corrosive aqueous solution such as an acid aqueous solution, an alkaline aqueous solution, or an aqueous solution of metal corrosive microorganisms to a water-absorbing material. The present invention will be described below with reference to the drawings. The drawings illustrate an embodiment of the invention, and FIG. 1 is a cross-sectional view of a time elapsed indicator. In FIG. 1, reference numeral 1 indicates a synthetic resin film, and this film 1 is bonded to an aluminum foil 3 via an adhesive 2 such as a urethane adhesive. Note that the surface of the aluminum foil 3 on the film 1 side has been subjected to anti-corrosion treatment in advance. Next, on the opposite side of this aluminum foil 3, write the letters,
Corrosion-proofing treatment is applied so that an untreated portion 5 remains in the shape of a figure, etc., and a colored water-absorbing material 7 is laminated so as to cover the entire surface of this untreated portion 5. Furthermore, the indicator of the present invention can be obtained by applying a heat seal lacquer 6 around the water absorbent material 7, but the heat seal lacquer 6 can be applied onto the water absorbent material 7 as long as it is permeable to a corrosive aqueous solution. It may also be applied. The following materials can be used for each component used in the present invention. The transparent synthetic resin film 1 of the present invention is, although not particularly limited, a synthetic resin film that can be firmly bonded to a corrosion-resistant aluminum foil surface via a urethane adhesive or the like, and is a film that is difficult to transmit water vapor. For example, polyester film, polypropylene film, etc. are preferable. In addition, the anti-corrosion treatment used for patterning the entire one side and the opposite side of the aluminum foil 3 uses a commonly used mixture of epoxy and phosphoric acid, etc.
Coating is carried out by gravure coating, and the treated film may be approximately 0.5 to 3.0 g/m ² . In the case of the present invention, the amount of coating was 23g/
m ² is preferable, but if the aging period is about 3 months
It can be used at 0.5 to 2 g/m ² . The shape of the non-processing portion 5 is, for example, characters, symbols, or designs indicating the expiry of the expiration period, such as "Expiration period has passed,""Pleasereplace,""3 months have passed,""6 months have passed," etc. The water-absorbent material 7 formed to cover the non-treated area 5 may be formed by directly coating various super absorbent resins into ink using a binder using a gravure plate, or by using polypropylene, polypropylene, etc. It is possible to construct a microporous liquid-absorbing film such as "NF sheet" manufactured by Tokuyama Soda Co., Ltd. in a pattern using an adhesive.
In either case, the object of the present invention can be achieved. Highly absorbent resins include polyacrylic acid-based resins (e.g., "Aqua Keep" manufactured by Seitetsu Kagaku Kogyo Co., Ltd. and "Sumikagel" manufactured by Sumitomo Chemical Co., Ltd.), isobutylene,
Maleic acid copolymer crosslinked products (e.g. "KI Gel" manufactured by Clareisoprene Chemical Co., Ltd.), starch-acrylic acid graft polymers (e.g. Sanyo Chemical Industries, Ltd.)
You can choose from a variety of products such as "Sunwet"). The heat seal lacquer 6 or the like applied around the water absorbent material 7 is not particularly limited, and may be heat sealable and tightly sealed with a synthetic resin film for covering the water absorbent material during use. It is fine as long as it can be opened. For example, when a heat seal lacquer such as a vinyl chloride vinyl acetate copolymer composition is used on the surface of a synthetic resin film, the same heat seal lacquer is used as the heat seal lacquer around the water-absorbing material. It is also possible to use a wax or the like whose main component is ethylene vinyl acetate or the like as a heat-sealing lacquer. In the indicator of the present invention, a corrosive aqueous solution such as an acid aqueous solution, an alkaline aqueous solution, or an aqueous solution of metal-corrosive microorganisms is applied to a water-absorbing material 7 to absorb the liquid, and then the water-absorbing material 7 is heated to another synthetic resin film using a heat seal lacquer 6. Seal and start using. As the acid aqueous solution and alkaline aqueous solution used as the corrosive aqueous solution, dilute acids such as dilute sulfuric acid and dilute hydrochloric acid, and extremely dilute aqueous solutions such as potassium hydroxide, sodium hydroxide, and sodium carbonate are used. The concentration of acid and alkali is related to the rate of corrosion, and the rate of corrosion and the thickness of the aluminum foil are related to the shelf life of the indicator, for example, thickness 9μ, 15μ, 20μ, 30μ
When an acid or alkali of about 1/100 to 1/1000 normal is used on each aluminum foil, the number of days until the aluminum foil corrodes and letters and figures appear on the back is 3 months, 6 months, 9 months, Can be adjusted to 12 months. Next, when using aluminum foil corrosive microorganisms, the bacteria include Pseudomonas aeruginosa,
Desulfovibrio desulfuqicans, Vibrio faecalis
Micrococcus caseolyticus, molds such as Cladosporium resinae are well known and can be used, but Cladosporium resinae, a type of mold, is
resinae are the best. In the present invention, the mold (Cladosporium
Bushnell-Hass
Grown in medium and at a spore concentration of approximately 10 ^{2 to 3}
1 to 2 ml of a spore suspension diluted with sterile physiological saline is absorbed into a water-absorbing material to make the indicator per ml. In this case, the thickness of the aluminum foil and the purpose of use of the indicator (duration, etc.) ),
The purpose can be achieved by adjusting the amount added. The synthetic resin film that covers the water-absorbing material during use is preferably the same material as the outermost transparent synthetic resin film 1, but is not particularly limited and may be any material as long as it is impermeable to water vapor. . FIG. 2 shows another embodiment in which a synthetic resin film 8 is pre-coated with a heat seal lacquer 6.
This indicator differs from the indicator shown in FIG. 1 in that the indicators are pasted together and a rubber sheet 9 is partially pasted thereon. This indicator in Figure 2 is
This is to eliminate the hassle of heat sealing the synthetic resin film to the heat seal lattice car during use.
The corrosive aqueous solution is injected through the rubber sheet 9 with a syringe. Since the needle hole is covered with the rubber sheet 9, water in the corrosive aqueous solution will not evaporate from this hole. Of course, instead of pasting the rubber sheet 9 together in advance, the needle hole can be protected with another film. <Function> This indicator shows that corrosion of the aluminum foil in the untreated area begins when a corrosive aqueous solution is applied to the water-absorbing material, and the corrosion progresses over time until holes appear in the aluminum foil after a certain period of time. When opened and viewed from the back side (film 1 side), the letters,
Shapes can be clearly identified. <Example> A time-lapse indicator according to the present invention was created in accordance with the following. Gravure coat a 25μ polyester film with 5g/m ² of urethane adhesive using a gravure plate with a plate depth of 80μ, and apply it to the anti-corrosion treated surface of a 20μ aluminum foil (coating amount: 1.5g/m2).
m ² ), apply a mixture of epoxy and phosphoric acid using a gravure plate with a plate depth of 60μ so that the words "Expiration date has passed" remain on the untreated side of the aluminum foil. Coated. After sufficiently drying, water absorbent resin ink (100 parts by weight of starch-sodium polyacrylate graft polymer, 100 parts by weight of ethylene-vinyl acetate copolymer, and 100 parts by weight of ethyl acetate) and a blue colorant were mixed to form an ink. (2000) was coated with a gravure plate with a plate depth of 80μ to cover the untreated area (approximately 10
g/m ² ), and approximately 6 g/m ² of ethylene-vinyl acetate heat seal lacquer was applied around the water-absorbing material to obtain an indicator material of the present invention. Next, a 25 μm polyester film was coated with about 6 g/m ² of the same heat seal lacquer on one side to prepare a film for covering a water absorbent material. Next, prepare three types of suspensions of Clados porium resinae spores: [] 1/50 N sulfuric acid, [] 1/100 N sodium carbonate, and [] 10 ² /ml as liquid agents for corroding aluminum foil, and add 2 ml of each. The solution was dropped onto a water-absorbing material to absorb the liquid, and the water-absorbing material was immediately heat-sealed with a heat-sealing plate to cover the water-absorbing material, thereby obtaining three types of time-lapse indicators. The above three indicators are measured at 0°~10°C, 15°~
The following table was obtained as a result of storage under three conditions: 25°C and 30° to 40°C and checking over time.

[Table] It was also confirmed that when the thickness of the aluminum foil was set to 9 to 12μ, characters could be distinguished in about 1/2 the time shown in this table. Furthermore, it was confirmed that even when the concentration of each liquid was doubled, characters could be distinguished in about 1/2 the time. Substantially the same results were obtained when a 100μ polyethylene microporous sheet (manufactured by Tokuyama Soda Co., Ltd.) was used instead of the water-absorbing resin in the sample of the above example. <Effects of the Invention> The present invention is as described above, and since corrosion starts from the time a corrosive aqueous solution is applied and the elapsed time from this time is measured, the product must be stored so as not to come into contact with air before use. There is no need to do so, and you can always measure the elapsed time after the start of use.

[Brief explanation of drawings]

The drawings show embodiments of the invention, FIGS. 1 and 2.
The figures are cross-sectional views of different indicators. 1...Synthetic resin film, 2...Adhesive, 3...
... Aluminum foil, 4 ... Treated section, 5 ... Untreated section, 6 ... Heat seal lacquer, 7 ... Water-absorbing material, 8 ... Synthetic resin film, 9 ... Rubber sheet.

Claims (1)

[Claims] 1. After laminating aluminum foil on one side of a transparent synthetic resin film and applying corrosion-proofing treatment to the aluminum foil surface in the shape of characters, figures, etc. so that a portion is left untreated, A time indicator made by laminating a water-absorbing material so as to cover the entire surface of the non-treated area and applying a heat-seal lacquer around the water-absorbing material. 2. The time elapsed indicator according to claim 1, wherein the water absorbent material is a coating film made of a super absorbent resin and a binder. 3. The time elapsed indicator according to claim 1, wherein the water-absorbing material is made of a microporous synthetic resin sheet.