JPS63130693A - Reversibly colorable temperature indicator composition and temperature indicating equipment using same - Google Patents

Abstract

PURPOSE:To obtain the title composition which is capable of color variation in the temperature range of a refrigerator or a freezer and provides economical temperature indicating equipment, by incorporating CoCl2 and a mixed solvent consisting of a specified organic solvent and water as essential ingredients. CONSTITUTION:An organic solvent (e.g. ethanol) capable of dissolving at least 1wt% of anhydrous CoCl2 at normal temperature and containing O in a molecule and water are mixed in such a ratio that the CoCl can change its color in a given temperature range, whereby a mixed solvent (A) is obtained. The ingredient A is incorporated with (B) CoCl2 which is in an amount of 0.5-1.5wt%, preferably 1.0+ or -0.2wt%, of the ingredient A in terms of anhydrous salt and (C) an organic solvent gelling agent (e.g. 1,3,2,4-dibenzylidenesorbitol) in an amount of 0.5-3.0wt% of the ingredient A to give the title composition. This composition is put in a transparent vessel and hermetically sealed to give a reversibly colorable temperature indicator. Separately, the above-mentioned composition is put in an open transparent vessel to obtain equipment indicating the service like of a deodorizer.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention mainly relates to a reversible color-changing temperature-indicating composition for determining whether the temperature of a refrigerator or freezer is maintained at an appropriate temperature by a beautiful color change; This invention relates to a reversible color-changing temperature indicator which is housed inside.

Conventional technology Traditionally, various thermometers have been used to display temperature.

In addition, color thermometers using thermochromic liquid crystals such as cholesteric liquid crystals have been put into practical use, but these are all expensive, so there are various types of color thermometers that change color in a specific temperature range or daily life temperature range. Progress has been made in developing reversible color-changing temperature-indicating materials.

For example, (1) JP-A-51-72982 describes a temperature indicating material in which 0.005 to 5% by weight of water-soluble cobalt salt is added to strontium chloride hexahydrate or bromide hexahydrate. (2) JP-A-56-159275 describes a reversible temperature-indicating composition in which a metal ion, a metal indicator, and a sequestering agent are dissolved and dispersed in an aqueous solution; Publication No. 56-167780 states that 3°4.
5. A thermochromic material composed of 6-dibenzo-1,2-oxaphosphane-2-oxide and a polyvalent metal compound is described. (5) JP-A-57-167'380 describes reversible moisture-indicating microcapsules containing a chemical organic compound, an electron-donating organic nitrogen compound, and a compound whose discoloration effect expires above a specific temperature. A reversible thermochromic material comprising an electron-donating color-forming colorless organic compound and an acidic phosphoric acid ester compound is described.

However, these reversible color-changing temperature indicating materials either change color at relatively high temperatures, or use expensive and special organic compounds even at low temperatures, and are in the temperature range for refrigerators and freezers. It changes color at -15 to 10°C, and
No one has been proposed that has a simple configuration and can be manufactured at low cost.

Problems to be Solved by the Invention The present inventors have overcome the problems of the prior art, and have developed a reversible color-changing temperature-indicating material that changes color in the temperature range of a refrigerator or 6-hour storage, and that can be manufactured at low cost with a simple structure. As a result of intensive research on the topic, we found that the color of a solution of cobalt chloride dissolved in a specific organic solvent that also dissolves water changes between pink and blue depending on the temperature, and furthermore, we found that the temperature at which the color changes The inventors completed the present invention by discovering that the discoloration temperature changes depending on the water content in the organic solvent, and that by appropriately adjusting the amount of water, the discoloration temperature can be adjusted to the refrigeration order or freezer operating temperature.・Means for solving the problems What is the gist of the present invention?

(1) A reversible color-changing temperature-indicating composition whose main components are an organic solvent that contains an oxygen atom in its molecular structure and dissolves cobalt chloride, or an organic solvent, an organic solvent gelling agent, water, and cobalt chloride.

(2) A reversible color-changing temperature indicating device formed by storing the above-mentioned reversible color-changing temperature-indicating composition in a transparent container and sealing the same, and (3) a transparent container containing the gel-like composition obtained using the above-mentioned organic solvent gelling agent. This is a deodorizer expiration date indicator that is housed in a container.

Hereinafter, the constituent elements of the present invention will be explained in detail.

(Organic Solvent) The organic solvent used in the present invention contains an oxygen atom in its molecular structure and is capable of dissolving 1% or more of anhydrous cobalt chloride by weight at room temperature. Examples of such organic solvents include 1, for example, ethanol, impropatol,
Examples include, but are not limited to, butanol, acetone, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, glycerin, etc. Furthermore, this organic solvent is not necessarily liquid at room temperature. For example, polyethylene glycol that is solid at room temperature can be used as long as it melts when heated. It is also possible to use a mixture of two or more of these organic solvents.

(Organic solvent gelling agent) The reversibly color-changing temperature-indicating composition of the present invention may be made using only an organic solvent, but if it contains an organic solvent gelling agent and the entire composition is made into a gel-like composition, it can be easily handled. In addition, the volatilization rate of solvent and water can be adjusted.

As the organic solvent gelling agent used in the present invention, for example, 1
, 3.2.4-dibenzylidene sorbitol, and this gelling agent is manufactured by Shin Nippon Chemical Co., Ltd. under the trade name Gelol D.

(Mixing ratio) The discoloration temperature of cobalt chloride dissolved in the mixed solution varies depending on the mixing ratio of the organic solvent and water. Therefore, by selecting the ratio, the discoloration temperature can be adjusted to a desired temperature. Table 1 shows the temperature at which the color of the solution changes when 1.0% by weight of anhydrous Kobal is dissolved in a mixed solution of ethanol as an organic solvent and water added in various proportions. It is something.

Table 1 (Note: The solution shows a beautiful color of pink at the low temperature side and blue at the high temperature side, with the discoloration temperature in Table 1 as the boundary point.) (Amount of cobalt chloride added) Used in the present invention The amount of cobalt chloride to be added is preferably 0.5% (as an anhydrous salt, the same applies hereinafter) to 1.5% by weight based on the mixed solution of organic solvent and water, and if it is less than 0.5% by weight, the color will turn pink at low temperatures. is very pale<,1. ! If the amount is more than Jl%, crystal precipitation tends to occur at low temperatures, so approximately 1.0±0.2% is particularly suitable. This ratio does not change even if the mixing ratio of organic solvent and water changes.

(Amount of organic solvent gelling agent used) The amount of organic solvent gelling agent used in the present invention is 0.5 to 3% by amount of Ofi based on the mixed solution of organic solvent and water.
, preferably 1.5 to 2.5% by weight. If m is less than 0.5% by weight, its effect as a gelling agent will not be recognized much, and if it is more than 3.0% by weight, it will not dissolve.

(Manufacturing method) To manufacture the composition of the present invention, an organic solvent, water and cobalt chloride are mixed in any order. If cobalt chloride does not completely dissolve at room temperature, use a suitable device to heat it and press Wl to dissolve it.

If the composition contains an organic solvent gelling agent, this gelling agent can also be added in any order.

Of course, cobalt chloride can be used as an anhydrous salt, but it is also possible to use hexahydrate salt and use its crystal water as water in the composition, and it is also possible to use cobalt chloride in the form of anhydrous salt. The same applies to cases where the present invention includes
This reversible color-changing temperature-indicating composition is placed in a transparent container made of plastic, glass, or the like, and the container is sealed to obtain a reversible color-changing temperature-indicating device. The mixing ratio of the organic solvent and water in the composition stored directly opposite the temperature indicator is varied depending on the purpose of use, such as the distinction between a refrigerator and a freezer.

Those skilled in the art will readily understand that the composition and temperature indicator of the present invention can be used in various fields not only to determine the appropriate temperature of a refrigerator or freezer, but also to identify temperature changes in low-temperature regions. This is understandable.

(Deodorant expiration date indicator) In the composition of the present invention, when the organic solvent used is volatile and the composition is a gel-like substance containing an organic gelling agent, this gel-like composition Items stored in open transparent containers can also be used as a tool to indicate the expiry date of deodorizers for refrigerators or freezers. If you store something in a container with a lid on it and leave it in the freezer compartment of a refrigerator for a long time with the lid off, the gel composition inside the container will gradually evaporate the organic solvent and water and maintain its pink color. It continues to shrink, but eventually remains as a dark blue-purple lump.The time it takes for the gel-like composition to reach this state corresponds to the effective period of use of the deodorant. By adjusting the amount of the gel composition and the shape of the container, the composition of the present invention can be used as the content of a tool that indicates the effective period of use of the deodorizer. It is of course possible to attach a scale to the container and use the scale as a guide to determine the effective period of use of the deodorizer without waiting for the deodorizer to turn into dark bluish-purple lumps.

EXAMPLES The present invention will be explained in detail below using Examples, but the present invention is not limited to these Examples.

Example 1 A mixed solution of ethanol and water in various ratios was prepared, and 1.0 g of anhydrous cobalt chloride was added to 100 g of the mixed solution. of
was added and heated while stirring to dissolve.

The solutions were cooled and heated, and the temperature at which the color of the liquid changed was measured. The results are shown in Table 1. This change was reversible.

Example 2 94.5 g of Improper Tool, 5.5 g of water and anhydrous cobal chloride) 1. og was mixed and dissolved, and the temperature at which the color of the solution changed was measured. The results are mixed solution No. in Table 1,
As with 3, the temperature was around 0℃.

The same experiment was also conducted using normal butanol instead of Impropatool. The result was also around 0°C, similar to mixed solution No. 3 in Table 1.

Example 3 92.0 g of Improper Tool, 8.0 g of water, 1.0 g of anhydrous cobal chloride) and 1.5 g of Gel Dairu D as an organic solvent gelling agent were mixed and cooled to form a blue gel composition. I got it. When 10 g of this gel composition was put into a test tube, sealed and placed in a household refrigerator, the gel composition in the test tube turned pink after some time. The temperature inside the refrigerator at this time was approximately 6°C. When the test tube was taken out and placed indoors, the gel-like composition inside the test tube turned blue after about 20 minutes. When this was placed in the same refrigerator again, the gel-like composition turned pink again.

Example 4 Ethanol 95. Og and water5. Dissolve 1.0 g of anhydrous cobal chloride in a mixed solution of Og, and add gelol D1
．． 5 g was added and heated to 75°C while stirring to dissolve. The blue solution thus obtained was heated to 50°C.
Since it was still liquid, 8.0 g of it was poured into a 10 mJl transparent plastic container with a 1.5 crn' opening, and the container was placed in the freezer compartment of a household refrigerator for 30 minutes. When observed later, the gel composition inside the container had a pink color. When this was left in the freezer, the volume of the gel-like composition had decreased to approximately 42% after three months while remaining pink. After another three months, the gel-like composition had become a dark bluish-purple blob.

This deadline corresponds to the Habo deodorizer expiration date.

Effects of the Invention The present invention provides a reversible color-changing temperature-indicating composition that has a simple configuration and can be used to determine the appropriate temperature in a refrigerator or freezer at low cost. This device has excellent effects, such as being able to easily produce a reversible color-changing temperature indicator and a deodorizer expiration date indicator, and has important industrial significance.

Claims (4)

[Claims] (1) A reversible color-changing temperature-indicating composition whose main components are an organic solvent that contains an oxygen atom in its molecular structure and dissolves cobalt chloride, water, and cobalt chloride. (2) The reversible color-changing temperature-indicating composition according to claim (1), wherein the main component further contains an organic solvent gelling agent. (3) Place a reversibly color-changing temperature-indicating composition whose main components are an organic solvent containing an oxygen atom in its molecular structure and dissolving cobalt chloride, or the organic solvent, an organic solvent gelling agent, water, and cobalt chloride in a transparent container. A reversible color-changing temperature indicator that is stored in a container and sealed. (4) A gel-like composition containing an organic solvent containing an oxygen atom in its molecular structure and dissolving cobalt chloride, an organic solvent gelling agent, water, and cobalt chloride as main components is housed in an open transparent container. Deodorizer expiration date indicator.