Reversible color changeable coating composition and preparation method thereof

Abstract

Provided is a reversible color changeable coating composition and a preparation method thereof. The composition is coated on a plate and has heat resistance of 400 C. or higher thereby can be used for heating products very stably, and the durability of the plate increases since it has excellent wear resistance, chemical resistance and mechanical properties. In addition, beautiful colors can be obtained by mixing colors in various ways, and being heated can be identified with the naked eye since the color changes when heated.

Claims

1. A method for preparing a reversible color changeable coating composition comprising the steps of: preparing a grinded substance with a ball mill by grinding a silica sol in 200 to 400 parts by weight, an alcohol in 100 to 300 parts by weight, and Fe.sub.2O.sub.3 in 100 to 300 parts by weight as a pigment and filler for the total weight of the coating composition; and adding a curing agent in 200 to 300 parts by weight to the grinded substance, wherein, in the step of grinding, a ball mill is performed with further adding metal powder, and wherein the metal powder comprises any one or more selected from the group consisting of Ag, Cu and Al.

2. The method for preparing a reversible color changeable coating composition according to claim 1, wherein the metal powder is added in 0.1 to 10 parts by weight.

3. The method for preparing a reversible color changeable coating composition according to claim 1, wherein the pigment and filler further comprises any one or more selected from the group consisting of Cd-Red, Cd-Yellow, Ti, Si, Al, Zr, Fe, Mn, Co and Cr; or oxides thereof.

4. The method for preparing a reversible color changeable coating composition according to claim 1, wherein, in the pigment and filler, Fe.sub.2O.sub.3 is 20% to 90% of the total weight of the pigment and filler.

5. A reversible color changeable coating composition, which is stirred after adding a curing agent in 200 to 300 parts by weight to a grinded substance of a silica sol in 200 to 400 parts by weight, an alcohol in 100 to 300 parts by weight, and Fe.sub.2O.sub.3 in 100 to 300 parts by weight as a pigment and filler for the total weight of the coating composition, wherein the grinded substance further comprises metal powder, and wherein the metal powder comprises any one or more selected from the group consisting of Ag, Cu and Al.

6. The reversible color changeable coating composition according to claim 5, wherein the metal powder is 0.1 to 10 parts by weight.

7. The reversible color changeable coating composition according to claim 5, wherein the pigment and filler further comprises any one or more selected from the group consisting of Cd-Red, Cd-Yellow, Ti, Si, Al, Zr, Fe, Mn, Co and Cr; or oxides thereof.

8. The reversible color changeable coating composition according to claim 7, wherein, in the pigment and filler, Fe.sub.2O.sub.3 is 20% to 90% of the total weight of the pigment and filler.

9. A reversible color changeable plate, in which a target area is coated with the coating composition of claim 5 and calcined.

10. A method for preparing a reversible color changeable plate, comprising the steps of: coating a target area of a plate with the coating composition of claim 5 and baking the coated plate.

11. A method for changing the color of a coated area by heating a reversible color changeable plate, in which a target area is coated with the coating composition of claim 5 and calcined, to a target temperature.

12. A reversible color changeable plate, in which a target area is coated with the coating composition of claim 6 and calcined.

13. A reversible color changeable plate, in which a target area is coated with the coating composition of claim 7 and calcined.

14. A reversible color changeable plate, in which a target area is coated with the coating composition of claim 8 and calcined.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The drawings show color changes depending on temperatures when a reversible color changeable coating composition in one specific embodiment of the present invention is coated on a target area of a plate and is calcined, wherein FIG. 1A depicts the target area before heating and FIG. 1B depicts the target after heating.

DETAILED DESCRIPTION OF THE INVENTION

(2) The best mode of the present invention provides a method for preparing a reversible color changeable coating composition, which comprises the steps of grinding a silica sol in 200 to 400 parts by weight, an alcohol in 100 to 300 parts by weight, and Fe.sub.2O.sub.3 in 100 to 300 parts by weight as a pigment and filler for the total weight of the coating composition using a ball mill; and adding a curing agent in 200 to 300 parts by weight to the grinded substance. In the specific embodiment, a method for preparing a reversible color changeable coating composition in which the step of grinding comprises ball milling with further adding metal powder is provided, a method for preparing a reversible color changeable coating composition in which the metal powder comprises any one or more selected from the group consisting of Ag, Cu and Al is provided, a method for preparing a reversible color changeable coating composition in which the metal powder is added in 0.1 to 10 parts by weight is provided, a method for preparing a reversible color changeable coating composition in which the pigment and filler further comprises any one or more selected from the group consisting of Cd-Red, Cd-Yellow, Ti, Si, Al, Zr, Fe, Mn, Co and Cr; or oxides thereof is provided, and a method for preparing a reversible color changeable coating composition in which, in the pigment and filler, the weight of Fe.sub.2O.sub.3 is 20% to 90% of the total weight of the pigment and filler is provided.

(3) Hereinafter, the constitutions and technological characteristics of the present invention are described in more detail with reference to the following examples. However, the following examples are for illustrative purposes only, and the scope of the present invention is not limited thereto.

Example 1

Preparation of Plate Comprising Reversible Thermochromic Ceramic Coating Layer

Experiment 1

(4) A grinded substance in a liquid state was obtained by adding 300 g of a silica sol in a particle size of 10 to 50 nm (water content-210 g), 200 g of isopropyl alcohol (IPA), 200 g of Fe.sub.2O.sub.3 as a pigment and filler, 1 g of silver powder and 4 g of copper powder in a size of 2 m as an additive to a ball mill and grinding them at a rate of 100 rpm for approximately 5 hours. 1 kg of a coating agent was obtained by adding 250 g of methyltrimethoxysilane (MTMS) to the grinded substance in a liquid state as a curing agent, and stirring and maturing the mixture for approximately 8 hours.

(5) An aluminum plate in a size of 100703 mm was sand treated using a 80# emery, was washed clean, was spray coated using the coating agent, and then was calcined for approximately 30 minutes at a temperature of 250 C. in a furnace, and as a result, a plate in a film thickness of 35 m was completed.

Experiment 2

(6) The coating agent and the plate were prepared using the same method as in Experiment 1. However, Fe.sub.2O.sub.3 and TiO.sub.2 in a total weight of 200 g were used in a weight ratio of 1:1 as the pigment and filler.

Experiment 3

(7) The coating agent and the plate were prepared using the same method as in Experiment 1. However, Fe.sub.2O.sub.3 and Cd-Red pigment in a total weight of 200 g were used in a weight ratio of 1:1 as the pigment and filler.

Experiment 4

(8) The coating agent and the plate were prepared using the same method as in Experiment 1. However, Fe.sub.2O.sub.3, Cd-Red and Co in a total weight of 200 g were used in a weight ratio of 1:1:2 as the pigment and filler.

Controls 1 and 2

(9) The coating agent and the plate were prepared using the same method as in Experiment 1. However, Fe.sub.3O.sub.4 or Co in a total weight of 200 g was used as the pigment and filler. The summaries thereof are shown in the following Table 1.

(10) TABLE-US-00001 TABLE 1 Ingredients Mixing Ratio Control 1 Fe.sub.3O.sub.4 1 Control 2 Co 1 Experiment 1 Fe.sub.2O.sub.3 1 Experiment 2 Fe.sub.2O.sub.3:TiO.sub.2 1:1 Experiment 3 Fe.sub.2O.sub.3:CdRed 1:1 Experiment 4 Fe.sub.2O.sub.3:CdRed:Co 1:1:2

Example 2

Identification of Color Changes of Plate Comprising Reversible Thermochromic Ceramic Coating Layer when Heated

(11) The plates of Controls 1 and 2 and Experiments 1 to 4 in Example 1 were heated to 90 C. to 150 C. As shown in the following Table 2, it was observed that color changes occurred at certain temperatures in Experiments 1 to 4, and the colors reversibly returned to their original colors after cooling.

(12) TABLE-US-00002 TABLE 2 Color Change Original Starting Color After Color After Color Temperature Heating Cooling Control 1 Black N/A Black Black Control 2 Blue N/A Blue Blue Experiment 1 Cherry 95 C. Black Cherry Coffee Experiment 2 Red Bean 100 C. Grey Red Bean Experiment 3 Red 110 C. Black Red Coffee Experiment 4 Black Red 120 C. Black Purple Black Red

Example 3

Variations in Color Changing Temperatures Depending on Metal Addition

(13) The coating agent and the plate were prepared using the same method as in Experiment 1 of Example 1. However, silver and copper powders were not added (Control 3), and when 0.1 or 10 g of silver or copper, which has excellent thermal conductivity, was added (Experiments 5 and 6), it was seen that the color change starting temperature dropped 10 C. to 20 C. as shown in the following Table 3.

(14) TABLE-US-00003 TABLE 3 Color Original Color Change Color After After Color Starting Temperature Heating Cooling Control 3 Cherry 115 C. Black Cherry Coffee Experiment 5 Cherry 100 C. Black Cherry Coffee Experiment 6 Cherry 95 C. Black Cherry Coffee

(15) While the present invention has been described for specific embodiments, it will be apparent to those skilled in the art that various changes may be made without departing from the scope of the present invention, and its components can be substituted with equivalents. In addition, various modifications may be made without departing from the fundamental scope of the invention, and specific conditions and materials may be employed as teaching contents of the present invention. Therefore, the present invention is not limited to particular embodiments that are delivered as the best mode planned to carry out the present invention, and the present invention needs to be interpreted to comprise all the embodiments defined in the attached claims.

(16) The plate of the present invention has heat resistance of 400 C. or higher thereby can be used for heating products very stably, and the durability of the plate increases since it has excellent wear resistance, chemical resistance and mechanical properties.