JPH0542378B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for forming a thermochromic film used for door glasses of toaster ovens and the like. [Prior Art] Until now, there has been no example of forming thermochromics on a glass plate that reaches temperatures of 200°C to 300°C. I mean,
For door glass of toaster ovens, etc.
As mentioned above, the temperature is relatively high at 200℃ to 300℃,
Conventionally available temperature control materials such as paint using thermochromic materials have a low heat resistance temperature (100
℃ or below), it was completely unusable. Therefore, in view of this point, the same applicant developed a thermochromic material with a high heat resistance temperature, and
Dated May 15, 1962 (Japanese Patent Publication No. 119599 (Japanese Patent Publication No. 62-11959)
-Refer to Publication No. 284283)). [Problems to be solved by the invention] When forming a Tl ₂ CrO ₄ based thermochromic film using an organic binder that can be used for a long time on door glass of oven starters etc. that reach temperatures of 200°C to 300°C, it is necessary to use an organic binder. As such, heat resistance, adhesion, and resistance to heat yellowing are required. Further, it is necessary that the thermochromic material powder does not react with the Tl ₂ CrO ₄ based substance and prevent the thermochromic color change. On the other hand, if you want to form a thermochromic film on the door glass after it has already been strengthened, a thermochromic ink that uses an organic binder is recommended because a frit-based binder that requires high-temperature baking will not be effective in strengthening the glass. It becomes necessary. Furthermore, when thermochromic printing is performed on unstrengthened glass to strengthen it, the organic binder cannot withstand the atmosphere of 700°C, which is the temperature of the strengthening process. Particularly in the case of door glass, in which a pattern is formed using inorganic ink and then strengthened, forming a thermochromic film after the strengthening process is easier in the production process, so it is a post-processing process. Therefore, thermochromics using organic binders are preferable. In addition, when using Tl ₂ CrO ₄ as a thermochromic material, the melting point of the Tl ₂ CrO ₄ material is approximately 620°C in an atmosphere where the temperature for strengthening treatment is 700°C, so it may melt and cause damage to frit type binders, glass materials, coatings, etc. Reactions with overlapping foreign pigments may inhibit thermochromic color change. For these reasons, a thermochromic quinine (Tl ₂ CrO ₄ type) using an organic binder with heat resistance, adhesion, and resistance to heat yellowing is required. [Means for Solving the Problems] As is clear from the embodiments shown in FIGS. 1 to 3, the present invention provides an inorganic compound-based ceramic material containing taliium chromate as a main component on the surface of the tempered glass. A pattern film is formed using a thermochromic ink made by mixing a thermochromic material and a polyimide resin binder, and then baked at a relatively low temperature that does not melt the thermochromic ink. [Function] According to the present invention, it can be used as a thermochromic material.
We use thallium chromate that can withstand continuous use at relatively high temperatures of 200°C to 300°C, and in order to use it as an ink, we use a polyimide resin that does not react with the thallium chromate as a binder.
It enables firing at a relatively low temperature, making it possible to form a thermochromic film that poses no problem in practical use. [Example] In FIG. 1, a pattern 4 is formed on a transparent reinforced door glass 3 (made of borosilicate tempered glass) attached to the door body 2 of a toaster oven 1, and when the temperature of the toaster oven 1 is increased, A thermochromic film (pattern film 8 to be described later) forming a part of the pattern 4 exhibits a color change. The thermochromic film has a heat resistance of 400°C because the temperature reaches 200°C to 300°C during operation of the toaster oven 1.
℃, materials with a temperature below 200℃ for color change are required.
A suitable material for this purpose is thallium chromate (Tl ₂ CrO ₄ ), which begins to change color at around 80°C and exhibits a clear color change above 150°C. The color changes from yellow to orange. Melting point is approximately 620℃
The maximum temperature at which it exhibits durability is 400°C. The pattern 4 is applied by repeating milk screen printing several times on the surface of the door glass 3 of the toaster oven 1 shown in FIG. 1 with the door handle 5 opened forward. The picture 4 in FIG. 2 is a view of the toaster oven 1 in FIG. 1 when the door body 2 is closed and viewed from the front. To form the pattern 4 in Figure 2, finish the pattern 6 with black inorganic ink from which the patterns 7 and 8 have been removed, and then paint over the black ink 6 to fill the pattern 8 with thermochromic ink. Next pattern 8
In order to fill in the pattern 7 with the same dummy color ink (yellow ink that does not change color) as (pattern film),
Paint over black ink 6. As shown in FIG. 3, the cross-section of the silk screen printing film obtained in the above three steps is as shown in FIG. In order to form the above pattern, in the example, the black ink No. 6 is finished with an Epoquine resin binder that adheres well to glass and a silk screen ink made of black inorganic pigment, and the dummy color No. 7 is finished with a heat resistant ink with good adhesion. Finished with silk screen ink using polyimide resin as a binder, toned to the same color as pattern 8. The thermochromic silk screen ink forming the pattern 8 (pattern film) is a thermochromic pigment Tl ₂ CrO ₄ or
For materials containing Tl ₂ CrO ₄ and other compounds,
A binder that is chemically inert and has good adhesion to the glass is required. In addition, there are materials that have good adhesion to the heat-resistant temperature at which they are used, and that do not burn or carbonize the binder. As an example, A is a transparent ink for silk screen made of polyimide resin as a binder, and 8 is finished with a ratio of Tl ₂ CrO ₄ and polyimide binder of 3:1, 2:1, and 1:1, and B is an acrylic silicone. Finished with resin transparent silk screen ink as a binder and a ratio of Tl ₂ CrO ₄ to binder of 1:1, C is a transparent liquid of polymerized silicate-based inorganic polymer resin as a binder, Tl ₂ CrO ₄ was mixed in a 1:1 ratio and silk screen printed to finish pattern 8. D is a transparent liquid of polymethylphenylsiloxane resin as a binder.
E is a 1 _: 1 blend of Tl ₂ CrO ₄ and finished by silk screen printing pattern ₈ . Finished by silk screen printing pattern 8, F is a 1:1 blend of Tl ₂ CrO ₄ using high temperature heat resistant transparent acrylic resin liquid as binder, finished by silk screen printing pattern 8,
G is finished by using a transparent paint made of polytitanocarbosilane as a binder, blending Tl ₂ CrO ₄ in a 1:1 ratio, and printing pattern 8 by silk screen. In the above printing, A is at 200℃ for 30 minutes, B is at 250℃
℃ for 10 minutes, C for 20 minutes at 200℃, D for 30 minutes at 180℃,
E and F are baked at 180℃ for 20 minutes, and G is baked at 250℃ for 10 minutes. The pattern 4 thus finished was installed in the toaster oven 1 shown in FIG. 1, and the toaster oven 1 was operated to evaluate heat resistance and thermoclock color change. Durability is evaluated by adhesion, discoloration, and color change after holding at 250℃ for 100 hours. These evaluations are shown in Table-1.

〔effect〕

Since the present invention is constructed as described above, it is possible to bake a thermochromic film with a high heat resistance temperature in a relatively low temperature range even on a glass plate for which it was difficult to know whether the temperature is high or low in the past. Therefore, when the thermochromic film is fired, there is no ink smearing or external leakage due to boiling phenomenon, resulting in an excellent finish, and the manufacturing process is also simplified, resulting in significant cost advantages. It's something you get.

[Brief explanation of the drawing]

Fig. 1 is a front view of a toaster oven having a thermochromic film formed by the method of the present invention, Fig. 2 is a front view of the same thermochromic film, and Fig. 3 is a sectional view of the main part of Fig. 2. . 8: Pattern film formed with thermochromic ink.

Claims (1)

[Claims] 1 A pattern film is formed on the surface of the tempered glass using a thermochromic ink made by mixing an inorganic ceramic thermochromic material containing thallium chromate as a main component and a polyimide resin binder, and then the thermochromic ink is A method for forming a thermochromic film characterized by firing at a relatively low temperature that does not melt the quinque.