KR102209545B1 - Heat-resistant coating solution having high moisture proof and coated steel sheet using the same - Google Patents

Abstract

The present invention relates to a heat-resistant coating composition having excellent high temperature and high humidity resistance and a coated steel sheet using the same, and more particularly, based on the total weight of the coating composition, silicone resin 15 to 40% by weight, phosphate ester compound 12 to 30% by weight, A heat-resistant coating composition comprising 5 to 20% by weight of a bromine compound, 0.5 to 5% by weight of a silane coupling agent, 1 to 7% by weight of one or more high-temperature and high-moisture resistance improvers among the group consisting of a magnesium compound and a calcium compound, and the remainder of the solvent; And a coating layer in which the heat-resistant coating composition is coated with an adhesion amount of 1 to 5 g/m 2 based on one side of the steel sheet.

Description

Heat-resistant coating solution having high moisture proof and coated steel sheet using the same}

The present invention relates to a heat-resistant coating composition having excellent high-temperature and high-humidity resistance, and a coated steel sheet using the same, and more particularly, to a heat-resistant coating composition suitable for use near a heat source for kitchens with high moisture due to excellent high-temperature and high-humidity resistance, and a heat-resistant coating steel sheet using the same. About.

Parts used near heat sources such as kitchen appliances such as gas ranges, microwave ovens, and electric ovens must have heat resistance, and stainless steel sheets or ceramic coated steel sheets are generally used.

However, since these materials are expensive, the demand for steel plates having excellent heat resistance and low cost is increasing. Moreover, since kitchen appliances are frequently exposed to a humid atmosphere, the steel plates used for their manufacture are resistant to high temperatures and high temperatures. It must also have moisture. In the case of insufficient high temperature and high humidity resistance of the steel sheet, the appearance and performance may be impaired due to the occurrence of blackening defects, which are a phenomenon that deteriorates as the appearance of the product turns black.

Conventionally, in order to obtain such a coated steel sheet having excellent heat resistance, it has been a common method to coat the steel sheet with a heat-resistant paint developed for painting. However, since these heat-resistant paints require high temperature and long-term heat treatment conditions, they are not applicable in continuous and mass production processes. For example, U.S. Patent Publication No. 2004-54044 discloses a composition in which an organic film forming agent, a hexafluoro composite such as titanium, zirconium, etc., and at least one inorganic compound are mixed in water. Because it contains, it may affect the environment, and the solution is composed of acid, so care must be taken when handling.

Therefore, the film is dried even at low temperature and short-time heat treatment, so that it can be applied in continuous and mass production processes, and has excellent high temperature and high humidity resistance and heat resistance, making it suitable to replace the conventional heat-resistant steel sheet as described above, and is economically advantageous. If a steel plate is provided, it is expected to be useful in related fields.

Accordingly, one aspect of the present invention is to provide a heat-resistant coating composition having excellent high temperature and high humidity resistance.

Another aspect of the present invention is to provide a coated steel sheet using the heat-resistant coating composition of the present invention.

According to one aspect of the present invention, based on the total weight of the coating composition, silicone resin 15 to 40% by weight, phosphoric acid ester compound 12 to 30% by weight, bromine compound 5 to 20% by weight, silane coupling agent 0.5 to 5% by weight , There is provided a heat-resistant coating composition comprising 1 to 7% by weight of one or more high-temperature and high-humidity-resistant improving agents from the group consisting of a magnesium compound and a calcium compound and the balance of the solvent.

According to another aspect of the present invention, the holding steel plate; And a coating layer in which the heat-resistant coating composition of the present invention is coated with an adhesion amount of 1 to 5 g/m 2 based on one side of the holding steel sheet.

According to the present invention, it is possible to obtain a heat-resistant coating solution composition with improved high temperature and high humidity resistance, and when the heat-resistant coating solution composition of the present invention is used, desired heat resistance can be sufficiently obtained by a thin coating layer, thus reducing the drying time when forming a coating layer. can do. Furthermore, when the heat-resistant coating layer is formed by using the coating composition of the present invention together with the phosphate layer, the thickness of the heat-resistant coating layer can be made thin, so that the drying time when forming the coating layer can be shortened, as well as the heat resistance and high temperature and high humidity resistance of the steel sheet. Can be significantly improved.

Hereinafter, preferred embodiments of the present invention will be described. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

As a result of repeating research to secure the heat resistance of the plated steel sheet, the present inventors obtained a heat-resistant coating solution composition with improved high temperature and high humidity resistance, and further formed a phosphate layer on the plated steel sheet, and then a coating layer using the coating composition of the present invention. In the case of forming, it was confirmed that the heat resistance and high temperature and high humidity resistance of the steel sheet were more remarkably improved, so that the desired quality can be secured even if the thickness of the heat-resistant coating layer is thin.

Moreover, as the thickness of the heat-resistant coating layer is reduced as described above, the drying temperature and drying time required for the formation of the coating layer are shortened, so that the present invention is applied to a continuous mass production process such as a hot-dip galvanized steel sheet or an electro-galvanized steel sheet. It is expected that production will be possible.

More specifically, the heat-resistant coating solution composition having excellent high-temperature, high-humidity resistance of the present invention includes 15 to 40% by weight of a silicone resin, 12 to 30% by weight of a phosphate ester compound, 5 to 20% by weight of a bromine compound, based on the total weight of the coating composition. %, 0.5 to 5% by weight of a silane coupling agent, 1 to 7% by weight of one or more high-temperature and high-humidity improvers among the group consisting of a magnesium compound and a calcium compound, and the remainder of the solvent, and the solvent is water, alcohol, or It is a combination.

In the present specification, the content of the coating composition may be based on the total weight of the coating composition. Meanwhile, in the present specification, the expression “at least one” described below means including one or a combination of two or more.

The silicone resin is a binder resin for forming a heat-resistant coating composition, and its molecular structure has a form of a siloxane bond (Si-O bond) in which silicon and oxygen alternate, and the silicon is composed of a methyl group, a phenyl group, and a hydroxy group. It may have at least one functional group selected from the group.

The silicone resin may be obtained commercially or may be prepared by a method well known in the art. For example, when metal silicon and methyl chloride are reacted at about 300°C using a catalyst, dimethyldichlorosilane, methyltrichlorosilane or A mixture of these is obtained, and a silicone resin produced by hydrolyzing this can be used. In addition, a silicone resin prepared by hybrid organic-inorganic synthesis of colloidal silica and a polymer resin may be used, and for example, a synthetic resin of colloidal silica-polyepoxyimide may be used.

When the content of the silicone resin is less than 15% by weight, based on the total weight of the coating composition, other components that impart heat resistance cannot be sufficiently dissolved, resulting in poor solution stability, and precipitation occurs in the heat-resistant coating composition. There is a problem. On the other hand, when the content of the silicone resin exceeds 40% by weight based on the weight, there is a problem in that the content of other components imparting heat resistance is relatively reduced, thereby reducing heat resistance.

The phosphate ester compound is a component for improving the heat resistance of the coating composition of the present invention, bisphenol A-bis (diphenyl phosphate) (BDP), triaryl phosphate isopropylate (TIPP 65), dimethylmethyl phosphate (DMMP), Tetraphenyl m-phenylene bis (phosphate) (RDP), triethyl phosphate (TEP), triphenyl phosphate (TPP), tris (1,3-dichloro-2-propyl) phosphate (TDCPP), tris (2-chloro Ethyl) phosphate (TCEP), and tris (2-chloroisopropyl) phosphate (TCPP) is preferably at least one selected from the group consisting of.

At this time, when the phosphoric acid ester compound is added in an amount of less than 12% by weight based on the total weight, there is a problem that sufficient heat resistance cannot be exhibited. When it exceeds the weight %, there is a problem that the solution stability is deteriorated and precipitation occurs.

The bromine compound is a component for improving the heat resistance of the coating composition of the present invention, hexabromocyclododecane (HBCD), tetrabromobisphenol A (TBBA), decabromodiphenylethane (DBDPE), decabromodiphenyl oxide (DBDPO), brominated polystyrene (BPS), and tris(tribromophenoxy)-s-triazine (FR-245) is preferably at least one selected from the group consisting of.

At this time, when the bromine compound is added in an amount of less than 5% by weight based on the total weight, sufficient heat resistance cannot be exhibited, and when it is added in excess of 20% by weight, the solution stability is deteriorated and precipitation occurs. .

The silane coupling agent serves to crosslink the silicone resin and other components to each other, thereby forming a coating layer having excellent heat resistance and corrosion resistance, preferably 3-mercaptopropyl trimethoxysilane, 3-mercaptopropyl methyl Dimethoxysilane or mixtures thereof may be used.

At this time, when the silane coupling agent is added in an amount of less than 0.5% by weight based on the total weight, the coating composition of the present invention cannot exhibit sufficient heat resistance and corrosion resistance, and the content exceeds 5% by weight based on solid content. There is a problem in that the solution stability is lowered and precipitation occurs.

On the other hand, the high-temperature and high-humidity improver is a component used to suppress the deterioration of blackening as the appearance of the product turns black in a high temperature and humidity atmosphere, and is preferably at least one selected from a magnesium compound and a calcium compound. Do.

Here, the magnesium compound preferably contains one or two or more of magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium stearate, magnesium epoxide, and magnesium citrate.

And it is preferable that the calcium compound contains one or two or more of calcium oxide, calcium hydroxide, calcium carbonate, calcium stearate, calcium citrate, calcium hydride, calcium carbide, calcium peroxide, and calcium acetate. .

In this case, the high temperature and high moisture resistance improving agent is preferably contained in an amount of 1% by weight or more in order to secure a blackening resistance effect. If the content is too large, the solution stability is deteriorated, so it is preferable to control the upper limit to 7% by weight.

By forming a coating layer on one or both sides of the holding steel sheet by using the heat-resistant coating composition of the present invention having the above composition, it is possible to maximize the heat resistance of the holding steel sheet.

In more detail, the coated steel sheet of the present invention comprises a holding steel sheet; And a coating layer in which the heat-resistant coating composition of the present invention is coated with an adhesion amount of 1 to 5 g/m 2 based on one side of the steel sheet.

The type of the steel sheet to be held is not particularly limited, and any steel sheet applicable to the purpose of the present invention may be used. However, preferably, the holding steel sheet may be a galvanized steel sheet, that is, a galvanized steel sheet having a zinc-based plating layer formed on the holding steel sheet.

The method of forming the zinc-based plating layer is preferably carried out by an electro-galvanizing method and a hot-dip galvanizing method, but is not limited thereto, and any method widely known in the art for forming a zinc-based plating layer is applied. This is possible.

In addition, the component system of the zinc-based plating layer is also not particularly limited, and a component system of the plating layer applied to a conventional electro-galvanized steel sheet or hot-dip galvanized steel sheet may be applied.

On the other hand, it is preferable that a phosphate layer is additionally formed between the holding steel sheet and the coating layer, and the phosphate layer improves the heat resistance and corrosion resistance of the steel sheet at the same time, thereby reducing the heat resistance and corrosion resistance when the thickness of the heat-resistant coating layer becomes thinner. It can be formed in advance to compensate.

For example, in the case of using a galvanized steel sheet as the holding steel sheet, in the case of coating treatment with the heat-resistant coating composition of the present invention after forming a phosphate layer on the galvanized layer, the heat resistance and corrosion resistance of the holding steel sheet are further improved, and the heat-resistant coating layer Even if the thickness of the product is thin, the desired quality can be sufficiently secured. Moreover, as the thickness of the heat-resistant coating layer is reduced, the drying temperature and drying time are shortened, so that application in the continuous mass production process of steel sheets such as hot-dip galvanized steel sheets or electro-galvanized steel sheets is facilitated.

The phosphate constituting the phosphate layer is preferably a metal phosphate containing at least one of aluminum, magnesium, manganese, and zinc, but is not limited thereto, and can be applied for conventional coating, and any phosphate based phosphate-based phosphate Can also be used.

The method of forming the phosphate layer may be performed by an immersion method or a spray method, but is not limited thereto, and any method known in the art may be applied as a method capable of forming a phosphate layer.

In this case, the phosphate layer is preferably formed with an adhesion amount of 1 to 5 g/m 2 based on one side of the steel sheet, and when the adhesion amount of the phosphate layer is less than 1 g/m ² , securing heat resistance and corrosion resistance is insufficient. In the case of exceeding 5g/m ² , there is a problem in that continuous mass production becomes difficult due to a long time required for coating.

Meanwhile, the method of applying the heat-resistant coating composition of the present invention for forming the coating layer is not particularly limited, and may be performed by, for example, an immersion method or a spray method, but is not limited thereto.

After applying the heat-resistant coating composition, a drying step may be performed, and the drying step may be performed at a temperature of 200° C. to 300° C. for 5 to 15 seconds, for example, induction drying, near-infrared drying, hot air drying, etc. It does not become.

According to the present invention, it is possible to obtain a heat-resistant coating solution composition with improved high temperature and high humidity resistance, and when the heat-resistant coating solution composition of the present invention is used, desired heat resistance can be sufficiently obtained by a thin coating layer, thus reducing the drying time when forming a coating layer. can do. Furthermore, when the heat-resistant coating layer is formed by using the coating composition of the present invention together with the phosphate layer, the thickness of the heat-resistant coating layer can be made thin, so that the drying time when forming the coating layer can be shortened, as well as the heat resistance and high temperature and high humidity resistance of the steel sheet. Can be significantly improved.

Hereinafter, the present invention will be described in more detail through specific examples. The following examples are only examples to aid understanding of the present invention, and the scope of the present invention is not limited thereto.

Example

1. Manufacture of coated steel sheet

After forming a phosphate layer with an adhesion amount of 3 g/m ² on an electro-galvanized steel sheet having a plating amount of 25/m2 on a single side by using PALBOND 3050, a zinc phosphate-based phosphate treatment agent of Paka Rising Co., Ltd., Table 1 below on the impression dye layer The coating composition of the composition disclosed in was applied in an amount of 3 g/m ² .

In Table 1 below, the silicone resin is a synthetic resin of colloidal silica-polyepoxyimide, the phosphate ester compound is dimethylmethyl phosphate, the bromine compound is hexabromocyclododecane, and the silane coupling agent is 3-mercaptopropyl trimethoxy. Silane and magnesium carbonate were used as the high-temperature and high-humidity improvers, respectively, and were prepared in the amounts shown in Table 1 below. At this time, the amount of ham corresponding to the remainder of each example shown in Table 1 is water and ethanol as solvents.

After coating, it was dried for 15 seconds at 270°C using an induction dryer to prepare a coated steel sheet having a thickness of 0.8 mm.

division Coating composition (% by weight) Silicone resin Phosphate ester
compound bromine
compound Silane
Coupling agent High temperature and high humidity enhancer Comparative Example 1 12 20 7 2 2 Example 1 15 20 7 2 2 Example 2 26 20 7 2 2 Example 3 40 20 7 2 2 Comparative Example 2 42 20 7 2 2 Comparative Example 3 26 10 7 2 2 Example 4 26 12 7 2 2 Example 5 26 30 7 2 2 Comparative Example 4 26 32 7 2 2 Comparative Example 5 26 20 2 2 2 Example 6 26 20 5 2 2 Example 7 26 20 20 2 2 Comparative Example 6 26 20 22 2 2 Comparative Example 7 26 20 7 0.2 2 Example 8 26 20 7 0.5 2 Example 9 26 20 7 5 2 Comparative Example 8 26 20 7 7 2 Comparative Example 9 26 20 7 2 0.5 Example 10 26 20 7 2 One Example 11 26 20 7 2 7 Comparative Example 10 26 20 7 2 11

2. Evaluation of properties of coated steel sheet

Experimental example 1: Evaluation of physical properties according to the composition of the coating composition

The heat resistance, high temperature and high humidity resistance, and solution stability of the coating solution disclosed in Table 1 were measured and shown in Table 2 below of the coated steel sheet prepared in 1.

(1) At this time, the heat resistance evaluation was evaluated based on the following criteria by holding the sample in an electric oven at 500° C. for 24 hours and then performing an X-cut on the film.

○: Peeling width 3 mm or less

X: Peeling width exceeding 3mm

(2) The high temperature and high humidity resistance evaluation The sample was kept in a thermo-hygrostat with a temperature of 50°C and a relative humidity of 95% for 120 hours, and then the color difference (delta E) value before and after was measured and evaluated according to the following criteria.

○: Delta E 2.0 or less

X: Delta E exceeds 2.0

(3) The solution stability evaluation was evaluated based on the following criteria by measuring the occurrence of sludge and viscosity after storing each coating composition disclosed in Table 1 in a 50°C thermostat for 3 days.

○: Viscosity change is within 20% and no precipitation or sludge occurs.

X: Viscosity change exceeds 20% or precipitation or sludge occurs

division Quality characteristics Heat resistance High temperature and humidity resistance Solution stability Comparative Example 1 ○ ○ X Example 1 ○ ○ ○ Example 2 ○ ○ ○ Example 3 ○ ○ ○ Comparative Example 2 X ○ ○ Comparative Example 3 X ○ ○ Example 4 ○ ○ ○ Example 5 ○ ○ ○ Comparative Example 4 ○ ○ X Comparative Example 5 X ○ ○ Example 6 ○ ○ ○ Example 7 ○ ○ ○ Comparative Example 6 ○ ○ X Comparative Example 7 X X ○ Example 8 ○ ○ ○ Example 9 ○ ○ ○ Comparative Example 8 ○ ○ X Comparative Example 9 ○ X ○ Example 10 ○ ○ ○ Example 11 ○ ○ ○ Comparative Example 10 ○ ○ X

As shown in Table 2, in the case of the coating composition according to the present invention, it can be seen that all of the heat resistance, high temperature and high humidity resistance, and solution stability were excellently evaluated.

Experimental example 2: Evaluation of physical properties according to adhesion amount

A phosphate layer having the same composition as in Example 1 was formed on the surface of the electro-galvanized steel sheet having a zinc adhesion amount of 15 g/m 2, but the adhesion amount was adjusted in the range of 0.8 to 6 g/m ² as shown in Table 3 below and coated.

On the other hand, using a coating composition having the same composition as in Example 2, as shown in Table 2 below, the amount of adhesion was adjusted in the range of 0.8 to 6 g/m ² and applied to evaluate the heat resistance, corrosion resistance, and operability according to the amount of adhesion. The results are shown together in Table 3 below.

Here, the evaluation of the heat resistance and high temperature and high humidity resistance was performed in the same manner as in Experimental Example 1, and operability was used as a standard for evaluation by measuring the rate of formation of the phosphate film and the drying rate of the heat-resistant coating layer. If is more than 20 seconds, it was judged as defective (X) because the productivity in the continuous line is extremely reduced.

division Adhesion (g/㎡) Quality characteristics Phosphate layer Heat-resistant coating layer Heat resistance High temperature and humidity resistance Workability Comparative Example 11 0.8 3 X X ○ Example 12 One 3 ○ ○ ○ Example 13 3 3 ○ ○ ○ Example 14 5 3 ○ ○ ○ Comparative Example 12 6 3 ○ ○ X Comparative Example 13 3 0.8 X X ○ Example 15 3 One ○ ○ ○ Example 16 3 5 ○ ○ ○ Comparative Example 14 3 6 ○ ○ X

As a result, as shown in Table 3 above, when the coating composition and the phosphate layer according to the present invention are formed by coating with an adhesion amount falling within the scope of the present invention, it can be confirmed that heat resistance and high temperature and high humidity resistance are also excellent, as well as excellent operability.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and variations are possible without departing from the technical spirit of the present invention described in the claims. It will be obvious to those of ordinary skill in the field.

Claims (13)

Based on the total weight of the coating composition, 15 to 40% by weight of a silicone resin, 12 to 30% by weight of a phosphate ester compound, 5 to 20% by weight of a bromine compound, 0.5 to 5% by weight of a silane coupling agent, magnesium carbonate, a high temperature and high humidity resistance improver A heat-resistant coating composition comprising more than 1% by weight and up to 7% by weight and the balance of the solvent.
The heat-resistant coating composition of claim 1, wherein the silicone resin has at least one functional group selected from the group consisting of a methyl group, a phenyl group, and a hydroxy group.
According to claim 1, wherein the phosphate ester compound is bisphenol A-bis (diphenyl phosphate) (BDP), triaryl phosphate isopropylate (TIPP 65), dimethylmethyl phosphate (DMMP), tetraphenyl m-phenylene bis ( Phosphate) (RDP), triethyl phosphate (TEP), triphenyl phosphate (TPP), tris (1,3-dichloro-2-propyl) phosphate (TDCPP), tris (2-chloroethyl) phosphate (TCEP), and Tris (2-chloroisopropyl) phosphate (TCPP) at least one selected from the group consisting of, heat-resistant coating composition.
The method of claim 1, wherein the bromine compound is hexabromocyclododecane (HBCD), tetrabromobisphenol A (TBBA), decabromodiphenylethane (DBDPE), decabromodiphenyl oxide (DBDPO), brominated polystyrene ( BPS), and tris(tribromophenoxy)-s-triazine (FR-245) at least one selected from the group consisting of, a heat-resistant coating composition.
The heat-resistant coating composition of claim 1, wherein the silane coupling agent is 3-mercaptopropyl trimethoxysilane, 3-mercaptopropyl methyldimethoxysilane, or a mixture thereof.
delete delete The heat-resistant coating composition of claim 1, wherein the solvent is water, alcohol, or a combination thereof.
Holding steel plate; And
A coating layer in which the heat-resistant coating composition of any one of claims 1 to 5 and 8 is coated with an adhesion amount of 1 to 5 g/m2 based on one side of the holding steel sheet
Containing, coated steel sheet.
The coated steel sheet according to claim 9, wherein the holding steel sheet is a galvanized steel sheet.
The coated steel sheet according to claim 9, wherein a phosphate layer is further formed between the base steel sheet and the coating layer.
The coated steel sheet according to claim 11, wherein the phosphate layer is formed with an adhesion amount of 1 to 5 g/m 2 based on one side of the steel sheet.
The coated steel sheet according to claim 11, wherein the phosphate constituting the phosphate layer is a metal phosphate containing at least one of aluminum, magnesium, manganese, and zinc.