KR20210093117A - Composition for enamel, method for preparation thereof and cooking appliance - Google Patents

Abstract

The present invention relates to an enamel composition that can be cleaned without a soaking process by moisture at room temperature, a method of manufacturing the same, and a cooking appliance. The enamel composition according to the present invention includes 1-40 wt% of SiO_2; 1-20 wt% of P_2O_5; 1-30 wt% of B_2O_3; 5-20 wt% of at least one among Li_2O, Na_2O, and K_2O; 1-5 wt% of at least one among NaF, CaF_2, and AlF_3; 3-15 wt% of MoO_3; 3-15 wt% of Bi_2O_3; 1-5 wt% of V_2O_5; and 1-5 wt% of TiO_2.

Description

Enamel composition, its manufacturing method, and cooking equipment {COMPOSITION FOR ENAMEL, METHOD FOR PREPARATION THEREOF AND COOKING APPLIANCE}

The present invention relates to an enamel composition capable of cleaning contaminants without soaking with water, a manufacturing method thereof, and a cooking appliance.

Enamel is a glassy glaze applied to the surface of a metal plate. Common enamel is used in cooking appliances such as microwave ovens and ovens. BACKGROUND ART Cooking appliances such as electric ovens and gas ovens are appliances that cook food using a heating source. Since contaminants generated during the cooking process adhere to the inner wall of the cavity of the cooking appliance, it is necessary to clean the inner wall of the cavity. The enamel is coated on the surface of the inner wall of the cavity of the cooking utensil to facilitate the removal of contaminants attached to the cooking utensil. In general, as a technology that can easily clean the inner wall of a cavity, a pyrolysis (pyrolysis) method of burning contaminants at a high temperature to make ashes is known, and as an enamel composition to which the pyrolysis (pyrolysis) method is applied, P ₂ O ₅ , SiO ₂ , B ₂ Enamel compositions comprising components such as O _{3 are known.}

However, even if the enamel composition _{contains P 2} O ₅ , SiO ₂ , B ₂ O ₃ , and group I oxides, in order to remove contaminants from poultry oil or monster mash, a soaking process with moisture is required for a certain time there is a problem.

In addition, as the P ₂ O ₅ and Group I oxides are included in the enamel composition, there is a problem in that the durability of the fired enamel composition is reduced.

[Patent Literature]

(Patent Document 1)

US Patent No. 3547098

An object of the present invention is to provide an enamel composition capable of cleaning contaminants such as poultry oil without a soaking process by moisture.

Another object of the present invention is to provide a new enamel composition having a composition ratio that does not deteriorate durability even when _{P 2} O _{5 , Group I oxides are included in the enamel composition.}

Another object of the present invention is to provide a novel enamel composition that does not need to consider adhesion with a base steel sheet.

In order to provide an enamel composition capable of cleaning all contaminants without soaking with moisture, the present invention provides a novel silicate-based enamel composition.

More specifically, the enamel composition according to the present invention is SiO ₂ 1 to 40% by weight; P ₂ O ₅ 1 to 20% by weight; B ₂ O ₃ 1 to 30% by weight; 5-20 wt% of at least one of Li ₂ O, Na ₂ O, and K _{2 O;} 1-5 wt% of at least one of NaF, CaF ₂ , and AlF _{3 ;} MoO ₃ 3-15 wt%; Bi ₂ O ₃ 3-15 wt%; V ₂ O ₅ 1-5 wt%; And TiO ₂ 1-5 wt%; contains.

In addition, in order to maximize the cleaning performance, the enamel composition according to the present invention is ZnO. One or more of Al ₂ O ₃ and MnO ₂ may be further included.

The enamel composition according to the present invention includes a novel silicate-based glass composition and has an effect of enabling cleaning without a soaking process by moisture.

In addition, the enamel composition according to the present invention has an effect that durability is not reduced by including additional components, and the cleaning performance can be maximized by controlling the content of some components.

In addition, since the enamel composition according to the present invention can be coated on the buffer layer formed on the base steel sheet, there is no need to consider adhesion with the base steel sheet.

1 is a front view showing a cooking appliance according to an embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of a part of an inner surface of a cavity of the cooking appliance of FIG. 1 .
FIG. 3 is an enlarged cross-sectional view of a portion of an inner surface of a door of the cooking appliance according to FIG. 1 .

The above-described objects, features and advantages will be described below in detail with reference to the accompanying drawings, and accordingly, those of ordinary skill in the art to which the present invention pertains will be able to easily implement the technical idea of the present invention. In describing the present invention, if it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

In the following, that an arbitrary component is disposed on the "upper (or lower)" of a component or "upper (or below)" of a component means that any component is disposed in contact with the upper surface (or lower surface) of the component. Furthermore, it may mean that other components may be interposed between the component and any component disposed on (or under) the component.

Also, when it is described that a component is "connected", "coupled" or "connected" to another component, the components may be directly connected or connected to each other, but other components are "interposed" between each component. It is to be understood that “or, each component may be “connected,” “coupled,” or “connected” through another component.

Throughout the specification, unless otherwise stated, each element may be singular or plural.

As used herein, the singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as "consisting of" or "comprising" should not be construed as necessarily including all of the various components or various steps described in the specification, some of which components or some steps are It should be construed that it may not include, or may further include additional components or steps.

Throughout the specification, when “A and/or B” is used, it means A, B or A and B, unless specifically stated to the contrary, and when “C to D” is used, it means that there is no specific contrary description. Unless otherwise specified, it means that it is greater than or equal to C and less than or equal to D.

Hereinafter, an enamel composition according to the present invention, a manufacturing method thereof, and a cooking appliance will be described in detail.

<Enamel composition>

The enamel composition according to the present invention is SiO ₂ 1 to 40% by weight; P ₂ O ₅ 1 to 20% by weight; B ₂ O ₃ 1 to 30% by weight; 5-20 wt% of at least one of Li ₂ O, Na ₂ O, and K _{2 O;} 1-5 wt% of at least one of NaF, CaF ₂ , and AlF _{3 ;} MoO3 3-15 wt%; Bi2O3 3-15 wt%; 1-5 wt% of V2O5; and 1 to 5 wt% of TiO2.

SiO ₂ is a component that forms a glass structure. SiO ₂ improves the chemical resistance of the enamel composition by strengthening the skeleton of the glass structure. The enamel composition according to the present invention contains 1 to 40 wt% _{of the SiO 2 .} If the SiO ₂ exceeds 40% by weight, it may interfere with the addition of the transition metal oxide, there may be a problem that the cleaning function is lowered. Conversely, if the SiO ₂ is less than 1% by weight, the glass structure may collapse.

P ₂ O ₅ is a component that functions to form a glass structure. In addition, P ₂ O ₅ is a glass former that facilitates the addition of a large amount of transition metal oxide in the enamel composition, and helps water permeate between the enamel surface and contaminants to easily remove contaminants. have The P ₂ O ₅ is contained in the range of 1 to 20% by weight. If the P ₂ O _{5 content} exceeds 20% by weight, vitrification of the enamel composition may be difficult and thermal properties of the enamel composition may be deteriorated. If P ₂ O ₅ is less than 1% by weight, the addition amount of the transition metal oxide is reduced, and the cleaning function may be deteriorated.

B ₂ O ₃ serves as a glass former and serves to uniformly dissolve each component of the enamel composition. In addition, B ₂ O ₃ improves the coating performance by controlling the coefficient of thermal expansion and fusion flow of the enamel composition. The B ₂ O _{3 -} is included in the enamel composition in an amount of 1 to 30% by weight. When the B ₂ O _{3 content} exceeds 30% by weight, it may interfere with the addition of the transition metal oxide, which may cause a problem in that the cleaning function is lowered. If the B ₂ O _{3 content} is less than 1% by weight, the glass structure may collapse.

Li ₂ O, Na ₂ O, and K ₂ O serve to improve the cleaning performance of the enamel composition. At least one of Li ₂ O, Na ₂ O, and K ₂ O is contained in the enamel composition in an amount of 5 to 20 wt%. When the _{content of at least one of Li 2} O, Na ₂ O, and K ₂ O exceeds 20 wt %, the thermal expansion coefficient of the glass is extremely increased, thereby deteriorating the coating performance. If the _{content of at least one of Li 2} O, Na ₂ O and K ₂ O is less than 5% by weight, there may be a problem in that the cleaning function is lowered.

NaF, CaF ₂ , and AlF ₃ are components that improve the surface properties of the enamel coating layer by controlling the surface tension of the enamel coating layer. At least one of NaF, CaF ₂ , and AlF ₃ is contained in the enamel composition in an amount of 1 to 5% by weight. When one or more of NaF, CaF ₂ , and AlF ₃ exceeds 5 wt%, thermal properties may be deteriorated. When at least one of NaF, CaF ₂ , and AlF ₃ is less than 1 wt%, the surface properties of the enamel coating layer may be deteriorated.

MoO ₃ , Bi ₂ O ₃ , V ₂ O ₅ and TiO ₂ function as catalysts on the surface of the enamel coating layer. These components easily break the connection between the surface of the enamel coating layer and contaminants. The enamel composition according to the present invention contains 3 to 15% by weight _{of MoO 3;} Bi ₂ O ₃ 3-15 wt%; V ₂ O ₅ 1-5 wt%; And TiO ₂ 1-5 wt%; contains. When the above components exceed the maximum content range, the addition of other components is prevented, which may cause a problem in that vitrification is difficult and thermal properties are lowered. On the other hand, if the components are included in less than the minimum content, the cleaning function of the enamel may be reduced. In order to clean the surface of the enamel coating layer without soaking at room temperature, a combination of the above catalyst components is required.

Next, the enamel composition according to the present invention contains 1 to 20 wt% of ZnO; Al ₂ O ₃ 1 to 20% by weight; And MnO ₂ It may further include one or more of 1 to 10% by weight. The above components compensate for the weak durability of the silicate glass structure, and have the effect of improving the hardness of the enamel surface. When the above components exceed the maximum content, the melting temperature of the composition may increase and the fusion flow may increase, thereby reducing the adhesion of the enamel coating layer. On the other hand, if each component is less than the minimum content, the durability of the enamel coating layer may be reduced.

Since the enamel composition according to the present invention has the above-mentioned novel composition ratio, it is possible to clean contaminants without a soaking process by moisture.

<Method for producing enamel composition>

Next, the method for producing an enamel composition according to the present invention comprises the steps of providing the above-described enamel composition material; melting the enamel composition material; and quenching the melted enamel composition material to form an enamel composition.

After sufficiently mixing the enamel composition material, the enamel composition material is melted. Preferably, the enamel composition material may be melted in a temperature range of 1200 to 1400 °C. In addition, the enamel composition material may be melted for 1 to 2 hours.

Thereafter, the melted enamel composition material may be quenched by a quencher using a chiller or the like. Accordingly, the enamel composition may be formed.

<Cooking equipment>

Next, the enamel composition according to the present invention may be coated on one surface of the target object to be coated with the enamel composition. The target object may be a part or all of a metal plate, a glass plate, or a cooking appliance. Preferably, it may be coated on the inner surface of the cavity of the cooking appliance or the inner surface of the door of the cooking appliance.

Referring to FIG. 1 , a cooking appliance 1 according to the present invention provides a cavity 11 in which a cooking compartment is formed, a door 14 for selectively opening and closing the cooking compartment, and heat for heating food in the cooking compartment. at least one heating source (13, 15, 16), a buffer layer (19, 20) coated on the inner surface of the cavity 11 or the inner surface of the door 14, and a coating layer formed by the enamel composition according to the present invention ( 17, 18).

The cavity 11 may be formed in a hexahedral shape with an open front surface. The heating sources 13 , 15 , and 16 include a convection assembly 13 for discharging heated air into the cavity 11 , an upper heater 15 disposed above the cavity 11 , and the cavity It may include a lower heater 16 disposed under the (11). The upper heater 15 and the lower heater 16 may be provided inside or outside the cavity 11 . Of course, the heating sources 13 , 15 , and 16 do not necessarily include the convection assembly 13 , the upper heater 15 , and the lower heater 16 . That is, the heating sources 13 , 15 , and 16 may include any one or more of the convection assembly 13 , the upper heater 15 , and the lower heater 16 .

Meanwhile, referring to FIGS. 2 and 3 , the enamel composition according to the present invention may be coated on the inner surface of the cavity 11 of the cooking appliance 1 or the inner surface of the door 14 by a dry process or a wet process. can The cavity 11 and the door 14 may be formed of a metal plate. Buffer layers 19 and 20 are formed on the surfaces of the cavity 11 and the door 14, and the coating layers 17 and 18 using the enamel composition according to the present invention are formed on the buffer layers 19 and 20. coated

The buffer layers 19 and 20 may be formed of a coating layer having a component similar to that of the enamel composition. In addition, the buffer layers 19 and 20 are preferably formed of a material having a matching coefficient of thermal expansion with the base steel sheet, and preferably formed of a material having excellent adhesion to the base steel sheet.

In the dry process, the enamel composition material is dispersed in an organic binder, and the mixed enamel composition material and the organic binder are milled in a ball mill to manufacture a glass frit. On the other hand, in the wet process, the enamel composition material is _{dispersed in water (H 2} O) and pigment (Pigment), and the mixed enamel composition material, water (H ₂ O), and pigment are milled in a ball mill. , a glass frit can be manufactured.

Thereafter, the glass frit according to the dry process and the wet process may be applied on the buffer layer by a spray method. The applied glass frit is fired for 100 to 450 seconds in a temperature range of 600 to 900° C., and to be coated on the inner surface of the cavity 11 of the cooking appliance 1 or the inner surface of the door 14 can

Hereinafter, specific aspects of the present invention will be described by way of Examples.

<Example>

<Preparation of enamel composition>

Enamel compositions having the composition ratios shown in Table 1 were prepared. The raw materials of each component were thoroughly mixed for 3 hours in a V-mixer. Here, the raw materials of _{P 2} O _{5 were NH 4} H ₂ PO ₄ , and _{the raw materials of Na 2} O, K ₂ O, and Li ₂ O were Na ₂ CO ₃ , K ₂ CO ₃ , and Li ₂ CO ₃ , respectively. did. The mixed material was sufficiently melted at 1300° C. for 1 hour and 30 minutes, and after quenching on a quenching roller, a glass cullet was obtained.

After controlling the initial particle size of the glass cullet obtained in the above process with a ball mill, and then pulverizing for about 5 hours using a jet mill, pass it through a 325 mesh sieve (ASTM C285-88) to control the particle size to 45 μm or less, A frit (powder) was prepared.

ingredient
(weight%) Example comparative example One 2 3 One 2 SiO2 37.44 21.94 28.42 14.36 14.36 P2O5 13.89 16.09 13.35 27.42 25.14 B2O3 15.87 8.72 11.05 13.19 24.01 Na2O 1.86 4.13 4.73 1.47 1.47 K2O 4.56 9.91 7.44 13.85 3.41 Li2O 0 0.87 0.91 2.81 2.22 NaF 0 1.72 0 0 0 AlF3 0 0 1.79 0 0 CaF2 3.19 0 0 2.61 8.11 Al2O3 0 4.18 9.72 7.88 4.01 TiO2 1.86 2.77 1.91 0 0 MnO2 7.42 3.01 0 0.28 0.28 V2O5 2 3.19 3.48 0 0 ZnO 0.93 6.35 0 4.91 4.81 ZrO2 0 0 0 5.88 7.89 MoO3 6.19 11.07 8.12 1.21 1.21 Co3O4 0 0 0 2.14 1.09 Fe2O3 0 0 0 1.25 1.25 Bi2O3 4.79 6.05 9.08 0 0 CeO2 0 0 0 0.74 0.74

<Preparation of enamel composition specimen>

First, a low-carbon steel sheet of 200 × 200 (mm) and a thickness of 1 (mm) or less to be used for the specimen was prepared.

A buffer layer having the components shown in Table 2 below was formed on the sheet. The buffer layer was prepared in the same manner as the above-mentioned enamel composition. The method of forming the buffer layer on the sheet is the same as the method of forming the enamel coating layer to be described later.

Next, frits prepared using the enamel compositions according to Examples and Comparative Examples were sprayed on the buffer layer using a corona discharge gun. The voltage of the discharge gun was controlled in a condition of 40 kV to 100 kV, and the amount of frit sprayed on the low-carbon steel sheet was 300 g/m 2 . The low-carbon steel sprayed with the frit was fired at a temperature of 830°C to 870°C for 300 seconds to 450 seconds to form a coating layer on one surface of the low-carbon steel. At this time, the coating layer was formed to a thickness of about 80㎛ to 250㎛. Through this, specimens according to Examples and Comparative Examples were prepared.

ingredient
(weight%) buffer layer SiO ₂ 48.8 B ₂ O ₃ 10.1 Na ₂ O 15 K ₂ O 10.7 Li ₂ O 4.2 NaF 6 TiO ₂ 2.4 Co ₃ O ₄ One NiO 0.5 Fe ₂ O ₃ 0.8 MnO ₂ 0.5

<Experimental example>

Performance evaluation was performed on the specimens according to the Examples and Comparative Examples as follows, and the results are shown in Table 3.

1. Cleaning performance for chicken oil contaminants

1 g of chicken oil as a contaminant is evenly and thinly applied to the surface of the specimen coated with the enamel composition on a metal substrate (100 × 100 (mm)), and then the specimen coated with contaminants is placed in a thermostat, 250-290 ° C. Contaminants were fixed for 1 hour in a temperature range of After the contaminants were fixed, the hardened contaminants were wiped with a force of 3 kgf or less with a frying pan-only scrubber moistened with room temperature water. Using a rod with a flat bottom of 5 cm in diameter, the part to be wiped from the surface of the contaminated specimen was uniformed.

2. Cleaning performance for monster mash

In addition, cleaning performance for monster mash was also measured in the same manner as in the previous method.

The number of reciprocations wiped at this time was measured on the specimens, and this was defined as the number of reciprocations of cleaning, and the cleaning performance evaluation index was described in Table 3.

number of round trips Level (LEVEL) 1 to 5 LV.5 6 to 15 LV.4 16 to 25 LV.3 26 to 50 LV.2 51 ~ LV.1

Example comparative example One 2 3 One 2 Chicken oil cleaning performance LV.5 LV.5 LV.4 LV.2 LV.1 Monster mesh cleaning performance LV.5 LV.5 LV.5 LV.1 LV.1

As shown in Table 4, it was confirmed that the Examples according to the present invention had excellent cleaning performance.

It was confirmed that the comparative examples did not have an optimal composition compared to the examples, and thus the cleaning performance was lowered.

Although the present invention has been described as described above, the present invention is not limited by the embodiments disclosed herein, and it is apparent that various modifications may be made by those skilled in the art within the scope of the technical idea of the present invention. In addition, although the effects of the configuration of the present invention are not explicitly described and described while describing the embodiments of the present invention, it is natural that the effects predictable by the configuration should also be recognized.

1: Cooking equipment
11: cavity
12 : galley
13: convection assembly
14 : door
15: upper heater
16: lower heater
17, 18: coating layer
19, 20: buffer layer

Claims (9)

SiO ₂ 1-40 wt%;
P ₂ O ₅ 1 to 20% by weight;
B ₂ O ₃ 1 to 30% by weight;
5-20 wt% of at least one of Li ₂ O, Na ₂ O, and K _{2 O;}
1-5 wt% of at least one of NaF, CaF ₂ , and AlF _{3 ;}
MoO ₃ 3-15 wt%;
Bi ₂ O ₃ 3-15 wt%;
V ₂ O ₅ 1-5 wt%; and
TiO ₂ 1 to 5% by weight; containing
Enamel composition.
The method of claim 1,
ZnO 1 to 20% by weight; further comprising
Enamel composition.
The method of claim 1,
Al ₂ O ₃ 1 to 20% by weight; further comprising
Enamel composition.

The method of claim 1,
MnO ₂ 1-10 wt%; further comprising
Enamel composition.
SiO ₂ 1-40 wt%;
P ₂ O ₅ 1 to 20% by weight;
B ₂ O ₃ 1 to 30% by weight;
5-20 wt% of at least one of Li ₂ O, Na ₂ O, and K _{2 O;}
1-5 wt% of at least one of NaF, CaF ₂ , and AlF _{3 ;}
MoO ₃ 3-15 wt%;
Bi ₂ O ₃ 3-15 wt%;
V ₂ O ₅ 1-5 wt%; and
TiO ₂ 1-5 wt%; providing an enamel composition material comprising;
melting the enamel composition material;
cooling the melted enamel composition material on a quenching roller to form an enamel composition
A method for preparing an enamel composition.
6. The method of claim 5,
The enamel composition material is
ZnO 1 to 20% by weight; further comprising
A method for preparing an enamel composition.
6. The method of claim 5,
The enamel composition material is
Al ₂ O ₃ 1 to 20% by weight; further comprising
A method for preparing an enamel composition.
6. The method of claim 5,
The enamel composition material is
MnO ₂ 1-10 wt%; further comprising
A method for preparing an enamel composition.
a cavity in which the galley is formed;
a door selectively opening and closing the cooking chamber;
at least one heating source providing heat for heating food in the cooking chamber;
a buffer layer coated on the inner surface of the cavity or the inner surface of the door; and
A coating layer coated on the buffer layer and formed by the enamel composition of any one of claims 1 to 4; including,
cooking equipment.

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