JPS63223082A - Temperature indicating composition - Google Patents

Abstract

PURPOSE:To obtain a temperature indicating composition having extremely clear change of color free from toxicity and flammability, not deteriorating operating environment, comprising an aqueous emulsion containing a complex showing remarkable change of color with dehydration. CONSTITUTION:A composition using an aqueous emulsion containing a complex showing change of color with dehydration, such as cobalt (II) and nickel (II) complex of hexamethylenetetramine [1,3,5,7-tetraazatricyclo (3,3,1,1<3.7>)decane].

Description

[Detailed description of the invention] (Industrial application field) TECHNICAL FIELD The present invention relates to a water-thermal composition.

(Prior art and problems) Temperature measurement using a substance that causes a significant hue change at a specific temperature is
It is convenient because it is easy to handle.

A thermochromic labeling composition comprising a complex salt, at least one type of rubber, and an organic solvent, which exhibits a remarkable color change upon dehydration, is introduced in JP-A-59-184269. However, the use of organic solvents may corrode the material whose temperature is being measured. In addition, there are problems with toxicity or flammability, which is unfavorable from a safety and health standpoint.

The above problem (means for solving the problem) In order to solve the above problem, the present inventor has made extensive research and has been able to achieve the present invention. That is, the present invention is a temperature-indicating composition comprising an aqueous emulsion containing a complex salt as a main component, which exhibits a remarkable color change upon dehydration. The complex salt used for this is hexamethylenetetramine (
1,3,5,7-thitraazatricyclo[3,3,1,
A cobalt (II) and nickel (II) complex of 13.7]decane (hereinafter referred to as hmta) was used.

These synthetic methods are described in M. Hallemelin and C. Duval, Microcimica Acta, 1962, p. 275. Also, the cause of the color change is dehydration of the aqua complex, and as the number of coordinated waters decreases to 6.4.2.0, coordination of anions occurs first, and then hmt
Three authors of references by the coordination of a: Kei Nagase, H. Kobayashi Kei Kune, Brain of the Chemical Society of Japan, 1976, Volume 49, 156
3 pages.

These complex salts include those that undergo a single color change between 50°C and 170°C, and those that change color in multiple stages, albeit discontinuously, as the temperature rises. That is, they have a kind of thermometric performance. However, since it is a water release type, in a humid atmosphere, water is taken in again to restore the color. It takes several minutes to several hours, but the color will be restored immediately if it comes into direct contact with water due to condensation. Further, in 100% moisture, it does not discolor when heated, and conversely, in low humidity of 10% or less or in a desiccant, it gradually dehydrates and discolors even without heating. Since discoloration is due to dehydration from the complex salt, if the coating film formed from the emulsion has poor gas release properties, the discoloration may become unclear, or the discoloration may not occur at a certain temperature. Therefore, the aqueous emulsion used in the present invention only needs to have heat resistance and air permeability, and for example, vinyl acetate, acrylic, synthetic rubber, vinylidene chloride, vinyl chloride, etc. can be used.

No special considerations are required for the production of the aqueous emulsion, and generally known methods may be used. Coatings formed from these water-based emulsions have good adhesion and are relatively porous. Therefore, water-based emulsions are excellent as color vehicles. A thermostatic composition can be obtained by adding a complex salt directly or in the form of an aqueous solution to an aqueous emulsion and stirring. Note that various additives may be mixed into the aqueous emulsion as necessary. Painting can be done by brushing or spraying, but there are no particular restrictions. Normally, the viscosity is adjusted to be suitable for brush application, but when spraying over a large area, lowering the viscosity with water makes it easier to apply. If you use a primer, it is best to allow it to completely dry and harden before applying it. However, if a darkly colored undercoat is used, the discoloration will become unclear, so it is preferable to use white.

(Effects of the invention) Since the solvent is water, there are no problems with toxicity or flammability. The temperature indicating material releases only water when heated, so it does not worsen the working environment. The discoloration is very obvious. It does not corrode the material whose temperature is being measured. Unlike other temperature measurement instruments, it can easily and inexpensively measure temperature distribution over a wide area by coating or forming a sheet.

(Example) Further, the present invention will be explained in detail using examples.

Example 1 Sevian A product number 117 manufactured by Daicel Chemical Industries, Ltd. was used as a vinyl acetate emulsion. As a complex salt, [N1(H2
O)6]C12-(hmta)Cl2-(h) was used.

Put 50g of Sevian A117 into a beaker, add 5g of the complex salt directly or in the form of a solution dissolved in a minimum amount of water, and stir thoroughly. After applying the adjusted thermostatic composition onto a glass plate using a bar coater with a thickness of 10 mils, the thermostatic composition was heated to 55°C.
After drying, a pale bluish-green transparent coating was obtained.

Example 2 A coating film obtained in the same manner as in Example 1 was dried at 105°C to obtain a pale yellow transparent coating film.

Example 3 A coating film obtained in the same manner as in Example 1 was dried at 155°C to obtain a purple transparent coating film.

Claims (1)

[Claims] A thermostatic composition comprising an aqueous emulsion containing a complex salt that exhibits a remarkable color change upon dehydration.