KR102079079B1 - Cooking utensil having thermochromic layer - Google Patents

Abstract

The present invention is a cooking utensil for forming a non-stick coating layer by laminating a lower coating layer, a pattern layer, and a top coating layer on the surface of a substrate. The cooking utensil comprises a thermochromic coating layer having the same color as the non-stick coating layer, and the thermochromic coating layer is formed by using a composition for thermochromic coating consisting of aminoalkylsilane, inorganic acid, an iron oxide-based inorganic pigment, a thermochromic pigment, a fluorine resin, and a solvent. The cooking utensil of the present invention exhibits a color variable effect which allows a pattern to appear on the surface of the cooking utensil.

Description

Cookware with thermochromic coating layer. {COOKING UTENSIL HAVING THERMOCHROMIC LAYER}

The present invention relates to a cookware having a thermochromic coating layer, wherein a red nonstick coating layer is formed on a surface of the cookware, and the thermochromic coating layer is formed when the cookware is heated by forming a thermochromic coating layer having the same color as the nonstick coating layer. It relates to a cooking utensil so that a pattern appears on the surface of the cooking utensil through the color change of.

In the kitchen utensils for cooking food, which is in contact only with a coating layer is generally formed on the metal surface. Since such a coating layer requires heat resistance, 70 to 80% is made of Teflon coating. Such a Teflon coating layer has a problem in that the manufacturing process is simple and excellent in non-sticking property, which is suitable for cooking utensils, but is worn or peeled off by use.

In order to solve this problem, the coating composition to form a coating layer is optimized to develop a product that improves the durability of the coating layer. In addition, by forming a pattern with a thermochromic ink so that the user can visually check the life of the coating layer to determine the replacement time of the product through the color change.

In addition, since the pattern formed of the thermochromic ink makes it possible to intuitively check the surface temperature of the cooking utensil, the convenience of use of the cooking utensil may be increased.

In Korean Patent No. 10-0740674, the upper color coating layer is formed on the upper surface of the non-stick coating layer of the cooking utensil so that the color is changed as the upper color coating layer is worn so that the user can visually check the replacement time.

However, in the prior art, the ink constituting the top color coating layer is not described, but simply changed from red to purple. The color of the coating layer printed with respect to the color of the surface of the cookware is changed from red to purple. There is a problem that it is not easy to recognize the sharp color change.

In addition, the Republic of Korea Patent Publication No. 10-2016-0092193, Republic of Korea Patent Publication No. 10-1292555 has a characteristic that the color change when heated by applying a thermochromic coating layer on the surface of the cooking utensils and return to the original color when cooled.

However, when the discoloration effect is expressed using Zion pigment, it is difficult to visually clearly identify the change in color, and there is a problem in that it is difficult to visually indicate the occurrence of wear due to use.

The present invention is to solve the problems of the prior art as described above, when forming a non-stick coating layer on the surface of the cooking utensils by forming a thermochromic coating layer of the same color as the non-stick coating layer to heat the cooking utensils It is an object of the present invention to provide a cooking utensil having a variable color effect such that a pattern appears on the surface of the cooking utensil through color change of the discoloration coating layer.

The cookware of the present invention for solving the above problems is a cookware comprising a non-stick coating layer formed by laminating a bottom coating layer, a pattern layer, and a top coat layer on the surface of the substrate, the cookware is the non-stick coating layer and It comprises a thermochromic coating layer of the same color, the thermochromic coating layer is characterized in that it is formed using a thermochromic coating composition consisting of aminoalkylsilane, inorganic acid, iron oxide-based inorganic pigments, Zion pigments, fluororesins and solvents.

In this case, the thermochromic coating layer may be to form a pattern layer of the cookware or to form a coating layer.

In addition, the aminoalkylsilane is characterized in that the aminoalkyl silane having 2 or 3 aminoalkyl groups.

The cooker according to the present invention forms a thermochromic coating layer of the same color as the non-stick coating layer when the non-stick coating layer is formed on the surface, so that the surface of the cookware through the color change of the thermochromic coating layer when heating the cookware. It exhibits a variable color effect that causes the pattern to appear on the screen.

1 is a cross-sectional view showing a surface laminated structure of the cooking appliance according to the present invention.
Figure 2 is a photograph observing the color change effect that appears when heating the surface of the cookware according to the invention, it is a photograph observing the state before (a) and after heating (b).
3 is a photograph observing the effect of the color change according to the temperature of the cooking utensil according to the present invention, room temperature (a), 50 ℃ (b), 100 ℃ (c), 150 ℃ (d), 200 ℃ (e) And a pattern in which the pattern formed by the thermochromic coating layer at 250 ° C. (f) is color changed.

Hereinafter, the present invention will be described in detail.

The present invention relates to a cooking appliance, characterized in that the thermochromic coating layer is formed. In general, a non-stick coating layer is formed on the surface of the cooking utensil, wherein the non-stick coating layer is formed by forming a top coat layer on the surface of the substrate and again laminating a top coat layer thereon, or laminating a middle coat layer and a top coat layer in turn.

In this case, a pattern layer may be formed by printing a pattern on the surface of the cooking utensil. In the cooking utensil of the present invention, a bottom coating layer, a pattern layer, and a top coat layer are laminated on a surface of a base to form a non-stick coating layer. In addition, the cooking apparatus of the present invention includes a thermochromic coating layer, characterized in that the thermochromic coating layer is the same color as the non-stick coating layer.

In the present invention, the non-stick coating layer is formed in red, by laminating a pattern layer on the undercoat coating layer to achieve a color change effect such that the pattern appears by heating of the cooking utensil. In this case, the pattern layer is formed in the same red color as the non-stick coating layer, through which the pattern layer does not appear at room temperature, i.e., without using a cooking utensil, but when the heating is performed using the cooking utensil, the pattern layer This will embody the visual effects that appear.

In addition, even when the red pattern layer is laminated on the red undercoat coating layer, the shape of the pattern formed by the printing thickness remains. Therefore, when the red translucent top coat layer is formed on the pattern layer, the shape of the pattern layer cannot be visually confirmed. Therefore, at room temperature, the surface of the cooking utensil becomes red overall.

In the present invention, two embodiments may be mentioned as a method of implementing the color change effect by heating. This will be described with reference to FIG. 1.

First, by applying the thermochromic coating layer to the pattern layer as shown in Figure 1 (a), it is possible to implement a color change effect through a laminated structure laminated on the red undercoat coating layer. The surface of the cookware manufactured by this method is the same as that shown in FIG. 2, but at room temperature as shown in FIG. 2 (a), no pattern appears on the surface, but when heated, the pattern layer as shown in FIG. The thermochromic coating layer constituting the color change causes a hidden pattern to be visually confirmed. In this case, the pattern may be implemented in various forms such as a specific figure, a logo, a character, a pattern, and the like.

In another embodiment, as shown in FIG. 1B, the undercoat coating layer may be a thermochromic coating layer, and a specific pattern may be printed thereon, and then the top coat layer may be laminated. In this case, no pattern appears on the surface at room temperature, but the printed pattern may appear because color change of the thermochromic coating layer forming the coating layer occurs even when the cooking utensil is heated.

Therefore, the cooking utensils of the present invention show the same color, brightness, and saturation at room temperature, and thus the color, lightness, and saturation of one coating layer are changed only when heated, so that the color change effect can be visually confirmed. In addition, in the present invention, by optimizing the composition for the thermochromic coating constituting the thermochromic coating layer, even if the cookware is used for a long time does not deteriorate the thermochromic coating layer can be displayed visibility.

The process of forming the coating layer is performed by repeatedly applying a coating layer with one coating composition and then drying and laminating the upper coating layer with another coating composition thereon. In addition, in the process of forming the pattern layer, it may be laminated through screen printing or pad printing.

In the present invention, since the non-stick coating layer is formed by using the coating composition including the iron oxide-based inorganic pigments, a red coating layer is formed as a whole.

The coating composition constituting the undercoat coating layer in the coating composition serves to protect the surface of the cooking utensil, and is an inorganic oxide pigment, a white inorganic pigment such as titanium dioxide or silica, and a ceramic inorganic binder such as a silane coupling agent. , Polyether sulfone (PES) resins, polyamideimide (PAI) resins, fluororesins, fillers and other additives may be used. In addition, the composition for the top coat is to form a transparent gloss surface, so a composition consisting of inorganic pigments and other additives selected from fluororesin, pearl pigment, silica or titanium dioxide can be used. In addition, all the fluororesins used in the present invention may be used PFA or PTFE, preferably a mixture of PTFE and PFA can be used. When using a mixture of PTFE and PFA it is preferable to mix in the range of 70 to 90% by weight PTFE and 10 to 30% by weight PFA, more preferably 80% by weight PTFE and 20% by weight PFA can be mixed. In addition, the additives include any one or a mixture of colorants, dispersants, antifoaming agents, fillers.

In addition, in addition to the top, bottom and thermochromic coating layers, a middle coating layer may be added as necessary. In this case, the intermediate coating layer may be formed on or under the thermochromic coating layer. Accordingly, the coating layer formed on the surface of the cooking utensil may be composed of three layers of a coating layer-a pattern layer-a top coat layer, or a coating layer-a pattern layer-a middle coat layer-a top coat layer, or four layers. It may be composed of four layers of a middle coating layer-a pattern layer-a top coat layer.

At this time, the composition for forming the intermediate coating layer may be a composition consisting of a fluororesin, inorganic pigments and other additives so as to have the same or similar color to the top coat, the bottom coat.

In addition, the thermochromic coating layer should be visually distinct from the initial state and the discoloration state according to the use of the cooking utensil, and the color contrast with the top coat layer should occur so that the color change may occur according to the use. In addition, since it may be applied to the undercoat coating layer it is necessary to have sufficient adhesion and durability to protect the surface of the cookware.

To this end, it is necessary to increase the thermochromic and color variable effects by improving the thermochromic coating composition for forming the thermochromic coating layer. In the present invention, a composition consisting of an aminoalkylsilane, an inorganic acid, an iron oxide inorganic pigment, a zion pigment, a fluororesin, and a solvent is used as the thermochromic coating composition. This allows the user to visually easily identify the effect of the color change more pronounced than the cooking utensils that cause color change using the Zion pigment in the prior art.

In order to increase the visual effect, there is a method of adjusting the content of the iron oxide-based inorganic pigment to realize the contrast pigment and the contrast color, but if the content of the iron oxide-based inorganic pigment is excessively increased, the dispersibility and compatibility is lowered and the stability is maintained for a long time. There is a problem that is difficult to be. Therefore, in the prior art, the composition is prepared in a two-component type containing an inorganic pigment and a zion pigment, respectively, or a coating composition is formed using the zion pigment at 10 wt% or less.

In the present invention, 5-10% by weight of aminoalkylsilane, 0.1-3% by weight of inorganic acid, 10-30% by weight of iron oxide-based inorganic pigment, 10-20% by weight of Zion pigment, fluorine as a composition constituting the thermochromic coating composition 10-20% by weight of the resin (particularly, PFA resin) and 30-40% by weight of the solvent are used, and the color difference is further increased by color change by controlling the contents of the iron oxide inorganic pigment and Zion pigment. have. In addition, according to the content of the iron oxide-based inorganic pigments to adjust the inorganic pigment content of the coating composition for the upper, middle, and lower coatings.

It is preferable to use the said aminoalkylsilane which is 2-3 aminoalkyl groups as said aminoalkylsilane. In the case of having 2 to 3 aminoalkyl groups, it was confirmed to exhibit an effect of improving the dispersibility of the iron oxide inorganic pigment and the Zion pigment. In addition, when the content of the aminoalkylsilane is too small, too much was found to reduce the particle dispersibility of the pigment.

Specific examples of such aminoalkylsilanes include tris (cyclohexylamino) methylsilane, bis (dimethylamino) methylsilane, bis (dimethylamino) dimethylsilane and tris (dimethylamino) silane. A better effect could be obtained when using double tris (cyclohexylamino) methylsilane, presumably because the cyclohexylamino group bonded to the silicon atom is larger in volume than the alkylamino group to promote dispersion between the pigment particles.

In addition, when the iron oxide inorganic pigments and Zion pigments are mixed, it becomes easy to visually check when color difference occurs while implementing a mixed color. The iron oxide-based inorganic pigments and Zion pigments may be contained by varying the content, the color of the thermochromic coating layer itself can be made clear by the content of Zion pigment to 10 to 20% by weight. In addition, when the content of the iron oxide-based inorganic pigments and Zion pigments is too much, the dispersibility is lowered and the durability of the coating layer is deteriorated, so it is preferably contained in the content range.

In addition, the inorganic acid may be hydrochloric acid or sulfuric acid, which is commonly used as being used for increasing the binding force in the coating process through the hydrolysis of the silane compound. However, if the content of the inorganic acid is too small or too much, the hydrolysis is insufficient or the durability of the coating layer due to the pH change.

In addition, it is preferable to use a mixed solvent of water and alcohol as the solvent. In the solvent consisting only of water, there is a problem in that the hydrolysis rate of the silane compound is excessively fast and the durability of the coating layer is reduced. For this purpose, it is preferable to mix water and alcohol in a weight ratio of 6: 4 to 9: 1. In addition, it is preferable to use ethanol or isopropanol as the alcohol, since the alcohol is commonly used in the sol-gel reaction of the silane compound.

In the present invention, the process of forming the coating layer on the surface of the cooking appliance may be specifically performed as follows.

The sandblasting surface-treated substrate is coated with a spray coating composition using a spray gun and heat-treated at about 200 ° C. for 5 to 10 minutes. Thereafter, the substrate is naturally cooled and coated with a spray gun sprayed onto the composition for top coat. The coated substrate may be placed in an oven again, heat treated at about 380 to 420 ° C. for 20 to 30 minutes, and then cooled to form a non-stick coating layer. In addition, in the case of forming the intermediate coating layer may be formed by spraying the coating composition for the intermediate coating with a spray gun on the heat-treated undercoat coating layer and then heat-processing it at about 200 ° C. for 5 to 10 minutes and then cooling the intermediate coating layer. have. In addition, the process of forming the thermochromic coating layer may also be carried out in the same process sequence, it is preferable to heat-treat at a time of less than 30 minutes to the temperature of the heat treatment to 200 ℃ or less according to the type of coating composition.

As a result of testing the visibility of the pattern layer according to the use of the cooking appliance according to the invention is shown in FIG. The surface of the cookware, in which the pattern layer is formed of the thermochromic coating composition on the undercoat coating layer, starts to appear at a temperature of red or 100 ° C. or more at room temperature, and when the temperature reaches 250 ° C., a clear pattern can be confirmed. In addition, the heating rate of heating is determined by the thickness and the material of the cooking utensil itself, but regardless of the heating rate it can be seen that causing a clear color change effect when the temperature is above a certain temperature. That is, as the temperature increases, the brightness and saturation of the pattern formed by the thermochromic coating layer become darker and darker, so that the user can visually check the surface temperature of the cookware through the color change of the pattern.

In order to evaluate the characteristics of the cookware according to the present invention, a frying pan was prepared as follows.

After coating the bottom coating layer on the surface of the frying pan and forming a pattern layer with a thermochromic coating composition thereon, a top coat layer was laminated to prepare a frying pan. The composition for the thermochromic coating was used as shown in Table 1.

In Example 1, tris (cyclohexylamino) methylsilane was used as the silane compound, and in Example 2, bis (dimethylamino) dimethylsilane was used. In Comparative Example 1, tetrakis (dimethyl amido) silane was used as the silane compound. In Comparative Example 2, tetraethylorthosilicate (TEOS) was used. In addition, the solvent used was a mixed solvent in which water and alcohol were mixed at a weight ratio of 7: 3.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Aminoalkylsilane 8 7 8 9.5 Inorganic pigments 22 22 22 22 Zion Pigment 18 18 18 18 Sulfuric acid 0.5 0.5 0.5 0.5 PFA 12 12 12 12 menstruum 39.5 40.5 39.5 38

In order to evaluate the basic physical properties of the prepared cookware, coating film thickness, gloss, surface hardness, adhesion, surface state, and nonstick properties were measured.

The film thickness and gloss were measured on 9 surfaces using a film thickness meter and a gloss meter, respectively, and the final measured value was determined as the average value of the remaining values except the maximum and minimum measured values.

The surface hardness is determined by using a pencil hardness tester, starting from pencil hardness 2H and then reciprocating 5 ~ 6cm up and down 10 times with up and down movement to determine whether there is an abnormality on the coated surface. It was.

In order to evaluate the adhesiveness, the surface of the surface was scratched with a lattice pattern, and the process of adhering and detaching the tape was repeated 10 times to evaluate the coating layer peeling.

Surface condition evaluation was evaluated by determining the pin-holes, cracks, etc. in the coating surface with a 50x magnification through the surface distribution test.

In addition, the non-stickability was evaluated by dropping off the surface by frying eggs in the state heated to 200 ℃ or more without applying cooking oil on the surface.

As a result, in Example 1, 2 and Comparative Examples 1 and 2, coating film thickness, gloss, surface hardness, adhesiveness, surface state, and nonstick property were all favorable.

Next, in order to evaluate the thermochromic effect, each frying pan was heated to measure the color coordinates of the pattern of the thermochromic coating layer and the surface color of the cookware (CM5 (Konica Minolta Ltd.), SCE mode (D65)). The results are shown in Table 2. In Table 2, (DELTA) L * is the value which calculated | required the brightness difference after room temperature and heating, and (DELTA) a * and (DELTA) b * are the values which calculated | required the chromaticity difference after room temperature and heating.

ΔL * Δa * Δb * Example 1 1.62 7.98 0.32 Example 2 1.39 8.84 0.56 Comparative Example 1 0.67 8.68 0.21 Comparative Example 2 0.22 8.28 0.14

 Looking at the results of Table 2, Examples 1 and 2 and Comparative Examples 1 and 2 both showed a thermochromic phenomenon by heating, showing a difference in chromaticity. In particular, in Example 1 and Example 2, the difference in brightness due to heating was large, and it was shown that the change in color due to thermochromic can be observed more clearly visually.

In addition, in order to evaluate the durability of the thermochromic coating layer formed on the frying pan, frying the eggs in a state in which the frying pan of Example 1 and Comparative Example 1 without heating the cooking oil at 200 ℃ or more and wash the cookware in a dishwasher After repeating the process 300 times, the difference in brightness and chromaticity with the initial state was measured. As a result, the cooking utensil of Example 1 did not show a significant change in the thermochromic coating layer before and after the test, but in Comparative Example 1 compared with before and after the test, the pattern of the thermochromic coating layer was blurred after the test and used for a long time. It was expected that the thermochromic coating layer would degrade. This is because the frying pan of Comparative Example 1 has no problem in the coating thickness, gloss, surface hardness, adhesion, surface state, and non-stickiness in the initial state, but surface damage occurs after long-term use, resulting in a thermochromic coating layer formed under the top coat layer. This suggests that it is affected.

Applying the thermochromic coating layer according to the present invention from this result it is possible to visually clearly identify the pattern due to the color change effect on the surface of the cookware, it is easy to detect the temperature change of the cookware surface during cooking, long-term use Edo cook was able to be used without deteriorating the thermal discoloration coating layer.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications or variations without departing from the scope of the invention. Therefore, the appended claims include such modifications and variations as long as they belong to the gist of the present invention.

Claims (3)

A cooking apparatus for forming a non-stick coating layer by laminating a bottom coating layer, a pattern layer, and a top coating layer on a surface of a substrate,
The cookware includes a thermochromic coating layer of the same color as the non-stick coating layer,
The thermochromic coating layer forms a pattern layer of the cookware or a bottom coating layer,
The thermochromic coating layer is 5 to 10% by weight of aminoalkylsilane, 0.1 to 3% by weight of inorganic acid, 10 to 30% by weight of inorganic oxide pigment, 10 to 20% by weight of Zion pigment, 10 to 20% by weight of fluororesin and 30 to solvent. It is formed using a composition for thermochromic coating consisting of 40% by weight,
The aminoalkyl silane is tris (cyclohexylamino) methyl silane, bis (dimethylamino) methyl silane, bis (dimethylamino) dimethyl silane or tris (dimethylamino) silane cooker formed with a thermochromic coating layer. delete delete

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