KR101696027B1 - Composite resin coating composition for steel sheet of fuel tank with exellent seam weldability and anti-mold, coated steel sheet using the composition and the method for preparing the coated steel sheet - Google Patents

Abstract

The present invention relates to a composite resin coating composition for imparting excellent core weldability and antifungal property to a steel sheet used for an automobile fuel tank among fuel tanks and a steel sheet coated with the composition, , 5 to 40 parts by weight of a curing agent; 1 to 10 parts by weight of a wetting agent; 1 to 15 parts by weight of a crosslinking agent; 0.1 to 3 parts by weight of a metal nano powder; And 0.001 to 0.1 part by weight of a pyrethroid compound; and a coating layer formed from at least one side of the base steel sheet on at least one side of the above-mentioned composite resin coating composition. The composite resin coating composition provided in the present invention can impart to the steel sheet the characteristics of excellent seam weldability, corrosion resistance, fuel resistance and antifungal property required for a steel sheet for a fuel tank, Steel plates for automobile fuel tank panels, more particularly steel plates for automobile fuel tank panels using bio-mixed fuels.

Description

Technical Field [0001] The present invention relates to a composite resin coating composition for a fuel tank steel sheet which imparts excellent seam weldability and antifungal property, and a steel sheet coated using the composite resin coating composition for a fuel tank steel sheet and a steel sheet coated therewith using the same. BACKGROUND ART AND THE METHOD FOR PREPARING THE COATED STEEL SHEET}

The present invention relates to a composite resin coating composition for imparting excellent core weldability and anti-moldability to a steel sheet used in an automobile fuel tank, and a steel sheet coated with the composition.

Automobile fuel tanks are manufactured by various types of welding such as spot welding, seam welding, brazing, and projection welding. Therefore, the steel plate for the fuel tank should have excellent welding characteristics, and at the same time, the corrosion resistance against the fuel should be excellent. In recent years, in order to reduce the use of fossil fuels, various types of biofuels are mixed with existing gasoline or diesel fuels.

In such automotive fuel tank steel sheets, zinc-plated steel sheets coated with a resin mainly composed of a polymer resin as a main component have been mainly used in order to secure excellent corrosion resistance. However, the resin-coated zinc-plated steel sheets are used for general gasoline and diesel oil. There is a problem that clogging of the fuel nozzle due to corrosion products may occur due to poor corrosion resistance to the composite fuel added with bioethanol and biodiesel.

In addition, since the zinc plated steel sheet contains an organic resin component having an insulating property on the coated surface, the welded property is poor, and in particular, there is a problem that welded parts are often defective due to heat of seam weldability, which is most important when manufacturing fuel tanks.

In order to solve such a problem, Japanese Laid-Open Patent Publication No. 1997-300415 has proposed a technique of improving the weldability by improving the conductivity by mixing metal particles with the polymer resin composition. However, such a technique has a disadvantage in that not only the manufacturing cost is high because the thickness of the coating film is increased, but also the workability is poor and metal powder is generated during processing, resulting in additional defects.

On the other hand, Japanese Unexamined Patent Application Publication No. 2002-298691 proposes a technique of applying an expensive Sn-Zn alloy hot-dip coated steel sheet. However, the above steel sheet is expensive and has a drawback in that corrosion resistance at the scratch area is very low.

In recent years, due to the gradual depletion of fossil fuels, the use of various kinds of fuels such as biofuels is increasing, and the use environment of the fuel tanks is getting worse and worse. In particular, It is necessary to develop a steel sheet for a fuel tank having better seam weldability and antifungal property.

An aspect of the present invention is to provide a composite resin coating composition which imparts excellent seam weldability, corrosion resistance, fuel resistance and antifungal property to a steel sheet for a fuel tank.

Another aspect of the present invention is to provide a steel sheet coated with a composition provided by the present invention, which is suitable for use in fuel tank panels for automobiles.

According to one embodiment of the present invention, a composition comprising 5 to 40 parts by weight of a curing agent, 1 to 10 parts by weight of a wetting agent; 1 to 15 parts by weight of a crosslinking agent; 0.1 to 3 parts by weight of a metal nano powder; And 0.001 to 0.1 part by weight of a pyrethroid based compound.

The composite resin coating composition may further include 0.5 to 5 parts by weight of a porous compound per 100 parts by weight of the main resin.

The composite resin coating composition may further include a solvent to have a solid content of 3 to 30% by weight.

The main resin may be at least one selected from the group consisting of an acrylic resin, a urethane resin, and an acrylic-modified urethane resin.

The subject resin may have a number average molecular weight of 2,000 to 20,000.

The curing agent may be at least one selected from the group consisting of melamine, butoxymethyl melamine, hexamethoxymethyl melamine, and trimethoxymethyl melamine.

The wetting agent may be at least one selected from the group consisting of tributyl phosphate, tricresyl phosphate and n-butyl phosphoric acid.

The crosslinking agent may be selected from the group consisting of gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropylmethyldiethoxysilane, gamma-aminopropyltrimethoxysilane, gamma-aminopropyltriethoxysilane, gamma-aminopropylmethyldimethoxy At least one selected from the group consisting of silane, isopropyl diantiethanol aminotitanium, lactic acid titanium chelate, titanium acetylacetonate, isopropyl ditriethanol amin zirconium, lactic acid zirconium chelate and zirconium acetylacetonate.

The average particle diameter of the metal nanopowder may be 10 to 500 nm.

The metal nanopowder may be composed of at least one metal selected from the group consisting of Ag, Al, Au, Co, Cu, Mo, Ni, Pd, W and Zn or an alloy thereof.

The pyrethroid compound is selected from the group consisting of Allethrins, Bifenthrin, Bioallethrin, Cyfluthrin, Cyhalothrin, Such as Cypermethrin, Cyphenothrin, Deltamethrin, Empenthrin, Imiprothrin, Metofluthrin, Permethrin, Penotrin, At least one selected from the group consisting of Phenothrin, Pyrethrin, Resmethrin and Tetramethrin.

The porous compound may be selected from the group consisting of mesoporous silica; Alumina; And at least one metal oxide selected from the group consisting of niobium oxide, tantalum oxide, titanium oxide, zirconium oxide, cerium oxide and tin oxide.

The solvent may be at least one selected from the group consisting of water, methanol, ethanol, propanol, butanol, pentanol, phenol, hexanol and cyclohexanol.

According to another embodiment of the present invention, there is provided a composite resin-coated steel sheet comprising a coating layer formed of the composite resin coating composition on at least one side of both sides of a base steel sheet.

The coating layer may be formed by coating the composite resin coating composition with an adhesion amount of 0.1 to 2.5 g / m < ² >.

The thickness of the coating layer may be 0.3 to 2 탆.

The steel sheet may be a galvanized steel sheet, a hot dip galvanized steel (GI) steel sheet, or a galvannealed (GA) steel sheet.

The composite resin coating composition provided in the present invention can impart to the steel sheet to which the above coating composition is applied the excellent core weldability, corrosion resistance, fuel resistance and antifungal property required for a steel sheet for a fuel tank.

Therefore, the steel sheet coated with the composition is suitable for use in steel plates for fuel tanks, specifically steel plates for automobile fuel tank panels, more specifically steel sheets for automobile fuel tank panels using bio-mixed fuels.

1 is a schematic cross-sectional view of a composite resin-coated steel sheet of the present invention.
Fig. 2 is a graph showing current ranges available for seam welding of the composite resin-coated steel sheets of Examples 2, 5, 14 and 18 and Comparative Example 1 in Experimental Example 1. Fig.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Further, the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art.

The present invention relates to a composite resin coating composition for imparting excellent core weldability and anti-moldability to a steel sheet used in an automobile fuel tank, and a steel sheet coated with the composition.

According to one embodiment of the present invention, there is provided a composite resin coating composition for a fuel tank steel sheet which imparts superior seam weldability and antifungal property, and more particularly to a composite resin coating composition for a fuel tank steel sheet which comprises 5 to 40 parts by weight of a curing agent, 1 to 10 parts by weight of a wetting agent; 1 to 15 parts by weight of a crosslinking agent; 0.1 to 3 parts by weight of a metal nano powder; And 0.001 to 0.1 part by weight of a pyrethroid compound.

The type of the main resin used in the composite resin coating composition of the present invention is not particularly limited, but at least one selected from the group consisting of an acrylic resin, a urethane resin and an acrylic modified urethane resin having excellent corrosion resistance to a biomix fuel can be used , Preferably an acryl-modified urethane resin.

Although not specifically limited, the number average molecular weight of the main resin may be 2,000 to 20,000. When the molecular weight is less than 2,000, the fuel resistance is deteriorated. When the molecular weight is more than 20,000, the storage stability and workability of the composition deteriorate.

The composite resin coating composition of the present invention may contain a curing agent, preferably a melamine curing agent together with the main resin, in order to improve the corrosion resistance and fuel resistance of the applied steel sheet. The kind of the melamine curing agent usable in the present invention is not particularly limited, but preferably at least one selected from the group consisting of melamine, butoxymethylmelamine, hexamethoxymethylmelamine and trimethoxymethylmelamine can be used.

The curing agent may be included in an amount of 5 to 40 parts by weight based on 100 parts by weight of the main resin. If the content of the curing agent is less than 5 parts by weight, the curing reaction of the dry coating film is not perfect and the physical properties of the coating film are poor. If the content exceeds 40 parts by weight, side reactions may occur due to excessive curing agent, .

The composite resin coating composition of the present invention may include a wetting agent to improve the adhesion of the coating composition. The kind of the wetting agent usable in the present invention is not particularly limited, but preferably at least one selected from the group consisting of tributyl phosphate, tricresyl phosphate and n-butyl phosphoric acid can be used.

The wetting agent may be included in an amount of 1 to 10 parts by weight based on 100 parts by weight of the main resin. If the content of the wetting agent is less than 1 part by weight, the wetting effect of the coating composition may be deteriorated and the composition may not be easily adhered to the substrate during the coating. If the content exceeds 10 parts by weight, Of course, the rapid decrease of the surface tension of the composition may cause a cratering phenomenon on the surface of the base paper during coating, and may adversely affect the adhesion of the coating film.

The composite resin coating composition of the present invention may contain a crosslinking agent to improve the corrosion resistance of the steel sheet to which the invention is applied. The kind of the crosslinking agent usable in the present invention is not particularly limited, but preferably at least one of a silane compound, a titanium compound and a zirconium compound can be used.

Examples of the silane compound include gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropylmethyldiethoxysilane, gamma-aminopropyltrimethoxysilane, gamma-aminopropyltriethoxysilane, and gamma-aminopropylmethyl Dimethoxysilane, and the titanium compound may be at least one selected from the group consisting of isopropyl di-triethanol aminotitanium, lactic acid titanium chelate, and titanium acetylacetonate, and the zirconium As the compound, at least one selected from the group consisting of amino zirconium isopropyl di-triethanol, zirconium lactate lactate and zirconium acetylacetonate can be used.

The crosslinking agent may be included in an amount of 1 to 5 parts by weight based on 100 parts by weight of the main resin. When the content of the crosslinking agent is less than 1 part by weight, the effect of improving the corrosion resistance may be insufficient even if the coating composition containing the crosslinking agent is applied to the steel sheet. When the content exceeds 5 parts by weight, the effect is saturated, The stability can be reduced.

The composite resin coating composition of the present invention may include a metal nano powder having excellent electrical conductivity to improve the seam weldability of a steel sheet to be applied. The metal nanopowder that can be used in the present invention is one comprising at least one metal selected from the group consisting of Ag, Al, Au, Co, Cu, Mo, Ni, Pd, W and Zn or an alloy thereof It is preferable to improve the electrical conductivity and ultimately improve the seam weldability.

At this time, in order to prevent the problem that when the metal nano powder is simply mixed with the polymer resin, powder is generated during processing or sludge is generated due to sedimentation of metal particles during roll coating, an average particle diameter of 10 to 500 nm is used .

When the average particle diameter of the metal nano powder is less than 10 nm, the cost may increase greatly and the cost of the coating composition may be increased. When the average particle diameter exceeds 500 nm, the specific gravity of the metal nano powder is large, If the composition is left to stand, the above-mentioned metal nano-powder may precipitate and become a problem in storage stability.

The metal nano powder is preferably contained in an amount of 0.1 to 3 parts by weight based on 100 parts by weight of the main resin. If the content of the metal nano-powder is less than 0.1 part by weight, the surface electrical conductivity of the dried coating film may be insufficient and the effect of improving the core weldability may be insufficient. When the content is more than 3 parts by weight, It can get worse.

The composite resin coating composition of the present invention may contain a pyrethroid compound as a repellent compound in order to impart antifungal properties to the applied steel sheet. The kind of the pyrethroid compound used in the present invention is not particularly limited, but is preferably selected from the group consisting of Allethrins, Bifenthrin, Bioallethrin, Cyfluthrin, Cyhalothrin, Such as Cypermethrin, Cyphenothrin, Deltamethrin, Empenthrin, Imiprothrin, Metofluthrin, Permethrin, Penotrin, At least one selected from the group consisting of Phenothrin, Pyrethrin, Resmethrin and Tetramethrin can be used.

The repellent compound is preferably contained in an amount of 0.001 to 0.1 part by weight based on 100 parts by weight of the main resin. When the content of the repellent compound is less than 0.001 part by weight, the effect of imparting antifungal properties may be insignificant. When the content exceeds 0.1 part by weight, the effect is saturated, and further addition is not meaningful, have.

In the present invention, the repellent compound may be dissolved in at least one solvent selected from the group consisting of water, methanol, ethanol, propanol and butanol, preferably dissolved in a mixed solvent of water and alcohol, have.

In addition, the composite resin coating composition of the present invention may include a porous compound so that when the coating composition is applied to a steel sheet, the repellent compound contained therein floats on the surface of the coating film and imparts excellent antifungal properties to the steel sheet. When the composite resin coating composition of the present invention contains a porous compound together with a repellent compound, the repellent compound can be incorporated into the pores formed in the porous compound and can float to the surface of the coating film as described above, Can exhibit antifungal properties stably.

At this time, the kind of the porous compound that can be used in the present invention is not particularly limited, but mesoporous silica; Alumina; And at least one metal oxide selected from the group consisting of niobium oxide, tantalum oxide, titanium oxide, zirconium oxide, cerium oxide and tin oxide can be used.

The porous compound may be contained in an amount of 0.5 to 5 parts by weight based on 100 parts by weight of the main resin. If the content of the porous compound is less than 0.5 parts by weight, the effect of floating the repellent compound incorporated in the pores into the surface of the coating film may be insignificant. If the content exceeds 5 parts by weight, the solution stability of the coating composition may be significantly reduced .

In addition, the viscosity of the composite resin coating composition of the present invention can be suitably controlled by further including a solvent. Examples of the solvent usable in the present invention include, but are not limited to, at least one selected from the group consisting of water, methanol, ethanol, propanol, butanol, pentanol, phenol, hexanol and cyclohexanol .

The amount of the solvent to be used is not particularly limited, but it can be adjusted to an appropriate level in consideration of the coating amount and adhesion of the coating composition of the present invention to the steel sheet, and for example, a Brookfield viscometer The solvent may be used so that the viscosity is 5 to 100 cps, and the solvent may be preferably contained in an amount of 3 to 30% by weight, more preferably 5 to 20% by weight, of the total weight of the composition.

According to another embodiment of the present invention, there is provided a composite resin-coated steel sheet comprising a coating layer formed of the composite resin coating composition provided by the present invention on at least one side of both sides of a base steel sheet.

FIG. 1 is a schematic cross-sectional view of a composite resin-coated steel sheet according to the present invention. Referring to FIG. 1, a structure of a composite resin-coated steel sheet according to the present invention will be described. A galvanized layer 2 is formed on both sides of a steel sheet 1 1 (a), a composite resin coating layer 3 belonging to the scope of the present invention is formed on one of the zinc plated layers 2 formed on both sides of the base steel sheet 1 1 (b), it can be seen that the composite resin coating layer 3 belonging to the scope of the present invention is formed on each of the zinc plated layers 2 formed on both sides of the base steel sheet 1. Further, it can be seen that the repellent compound (4) floats on the surface of the coating layer in the composite resin coating layer (3).

In the composite resin-coated steel sheet of the present invention, the coating layer may be formed so that the composite resin coating composition of the present invention has a thickness of 0.1 to 2.5 g / m ² And can be formed by coating with an adhesion amount. When the deposition amount is less than 0.1 g / m ² , the corrosion resistance and fuel resistance required in the present invention can not be ensured. When the deposition amount exceeds 2.5 g / m ² , the insulating property becomes large and the weldability may be poor.

The thickness of the coating layer may be 0.3 to 2 탆. When the thickness of the coating layer is less than 0.3 탆, it is difficult to ensure sufficient corrosion resistance and fuel resistance while the coating film thickness is thin. When the thickness exceeds 2 탆, corrosion resistance and fuel resistance are improved, but insulation property increases and weldability may be deteriorated.

The base steel sheet used in the composite resin-coated steel sheet of the present invention is not particularly limited in its kind, but the base steel sheet may be a sheet having a plated layer. Specific examples of the base steel sheet include galvanized steel sheet, hot dip galvanized steel sheet, It may be a hot-dip galvanized (GA) steel sheet.

At this time, the zinc-plated steel sheet may include all of zinc-free, zinc-containing two or three alloy-plated steel sheets, hot-dip galvanized steel sheets, and dry galvanized steel sheets. Zn-X (X = Fe, Co, Ni, Mg) is preferable for the two kinds of alloys and Zn-AB (A = Al, B = Si, Mg) is preferable for the three kinds of alloys. In particular, as the zinc-plated steel sheet, it is more preferable that the cold-rolled steel sheet is plated with zinc or zinc alloy, molten zinc or molten zinc with an amount of plating of 5 to 60 g / m ² .

The composite resin-coated steel sheet of the present invention can be produced by coating the composite resin coating composition on at least one surface of a base steel sheet by roll coating, spray coating, dipping, bar coating, slot-die coating or curtain ) Coating, followed by drying.

At this time, the drying method is not particularly limited and can be carried out by a method generally used in this technical field. However, the baking temperature of the coating layer is preferably in the range of 80 to 200 ° C on the basis of the steel plate temperature (PMT), and when the temperature is less than 80 ° C, the curing reaction is insufficient and it is difficult to secure corrosion resistance and fuel resistance Do. On the other hand, if the temperature is higher than 200 ° C, the crosslinking reaction of the melamine curing agent may be excessively increased, resulting in hardness of the coating film and poor processability.

In addition, in the present invention, in addition to the above conditions, the composite resin coating composition of the present invention can be dried by hot air treatment for 5 to 50 seconds at an atmospheric temperature of 200 to 340 ° C. to form a coating layer, 5 to 50 MHz and electric power of 3 to 15 KW for 5 to 20 seconds to form a coating layer, or may be formed by drying by infrared and near-infrared heating.

Hereinafter, the present invention will be described more specifically by way of specific examples. The following examples are provided to aid understanding of the present invention, and the scope of the present invention is not limited thereto.

[ Example  1 to 14 and Comparative Example  1 to 3] Production of composite resin-coated steel sheet

An acrylic-modified urethane resin, urethane resin or acrylic resin having a number average molecular weight of 6000 was used as the main resin. To this main resin, a hexamethoxymethylmelamine curing agent, a n-butylphosphate wetting agent, a titanium triethanolamine isoprox- ance crosslinking agent , A nickel nano powder having an average particle diameter of 70 nm, a lambda-cyhalide retarder, and mesoporous silica were mixed in the amounts shown in Table 1 to prepare a composite resin coating composition.

The composite resin coating composition thus prepared was roll-coated with an electrodeposited galvanized steel sheet (Zn-Ni, one-sided plating amount 30 ± 3 g / m ² ) as shown in Table 1, followed by drying at PMT = 170 ° C., A composite resin coated steel sheet was produced.

division Content (parts by weight) Adhesion
(g / m ² ) Theme balance Hardener Wetting agent Cross-linking agent Porous compound Metal nano powder Repellent agent Example 1 100 (acryl-modified urethane resin) 10 One 5 One 0.5 0.01 0.5 Example 2 10 2 1.0 0.03 1.0 Example 3 5 5 3 2.0 0.05 2.0 Example 4 10 One 0.5 0.01 0.5 Example 5 20 One 5 2 1.0 0.03 1.0 Example 6 10 3 2.0 0.03 2.0 Example 7 5 5 One 0.5 0.03 0.5 Example 8 10 2 1.0 0.05 1.0 Example 9 30 One 5 3 2.0 0.01 2.0 Example 10 10 One 0.5 0.03 0.5 Example 11 5 5 2 1.0 0.05 1.0 Example 12 10 3 2.0 0.05 2.0 Example 13 100 (urethane resin) 20 2 10 2 0.5 0.01 1.0 Example 14 100 (acrylic resin) 20 2 10 2 0.5 0.01 1.0 Comparative Example 1 100 (acryl-modified urethane resin) 20 5 10 One 0 0 1.0 Comparative Example 2 One 0.5 0 1.0 Comparative Example 3 One 0 0.01 2.0

[ Experimental Example ]

The evaluation results are shown in Table 2, and the results are shown in Table 2. The results are shown in Table 2. The results are shown in Table 2, The welding current ranges (kA) of Examples 2, 5, 11, and 14 and Comparative Example 1 were compared and shown in the graph of FIG. 2, and further detailed evaluation methods of the properties are as follows.

≪ Property evaluation method &

(1) Corrosion resistance

The corrosion resistance was evaluated by the rust generation area% of the steel plate specimen sprayed on a steel sheet at a spray pressure of 1 Kg / m ² at 35 ° C and 5% salt water using a salt water spraying apparatus (JIS E2731, Japan Industrial Standard Test Method). The resin coating film was evaluated in terms of percent red generation area after 1,000 hours passed after spraying with salt water.

◎: Corrosion area is 0%

○: Corrosion area less than 5%

?: Corrosion area is 5 to 30%

X: Corrosion area of 30% or more

(2) Evaluation of fuel property

The evaluation of fuel resistance was evaluated by the high temperature resistance of ethanol and biodiesel. The evaluation specimens were evaluated after putting the fuel into the cups (diameter 50 mmf, depth 30 mm), covering them with an o-ring and a glass plate, and fixing them. The evaluation of fuel property in gasoline was evaluated by evaluating the corrosion state of the steel sheet by shaking 90% of lead-free gasoline, 10% of bioethanol and 20 ppm of formic acid at 60 DEG C for 1000 hours at 60 rpm. The corrosion resistance of the steel sheet was evaluated by shaking 90% of diesel fuel + 10% of biodiesel + 100 ppm of formic acid at 80 ° C for 8 weeks at 60 rpm. The evaluation criteria are as follows.

◎: Corrosion area is 0%

○: Corrosion area less than 5%

?: Corrosion area is 5 to 30%

X: Corrosion area of 30% or more

(3) Evaluation of seam weldability

The seam weldability was evaluated by using an Interbore DC seam welder on a steel plate having a thickness of 0.8 mm under conditions of a pressing force of 4 KN, an energization time of 33 ms, and a dwell time of 10 ms. The evaluation criterion was evaluated as possible welding current range at seam welding speed of 6mpm.

◎: 2 kA or more

○: 1.0 kA or more and 2.0 kA or less

?: 0.5 kA or more and 1.0 kA or less

×: 0.5 kA or less

(4) Antimicrobial and antifungal performance evaluation

The antifungal property was evaluated according to the ASTM G 21 (2009) standard. Fungal strains were Aspergillus niger (ATCC 9642), Penicillium pinophilum (ATCC 11797), Chaetomium globosum (ATCC 6205), Giocladium virens (ATCC 9645) and Aureobasidium pullulans (ATCC 15233) were mixed and used. The fungus resistance was evaluated by evaluating the growth area of mold mycelium at 1, 2, 3, and 4 weeks after inoculating the strain on the surface of a steel plate (size 50x50 mm).

◎: The area of mycelial growth area in the inoculated portion of the test piece is less than 5% of the whole area

○: The area of the mycelial growth part in the inoculated part of the test specimen is 5 to 10% of the whole area

△: The area of mycelial growth part in the inoculated part of the test piece is 10 to 30% of the whole area

X: The area of the mycelial growth portion in the inoculated portion of the test piece is 30% or more of the total area

division Quality characteristics Corrosion resistance Fuel properties in gasoline Fuel properties in diesel Core weldability Antifungal Example 1 ○ ◎ ◎ ◎ ◎ Example 2 ◎ ◎ ◎ ◎ ◎ Example 3 ◎ ◎ ◎ ◎ ◎ Example 4 ○ ◎ ◎ ◎ ◎ Example 5 ◎ ◎ ◎ ◎ ◎ Example 6 ◎ ◎ ◎ ◎ ◎ Example 7 ○ ◎ ◎ ◎ ◎ Example 8 ◎ ◎ ◎ ◎ ◎ Example 9 ◎ ◎ ◎ ◎ ◎ Example 10 ○ ◎ ◎ ◎ ◎ Example 11 ◎ ◎ ◎ ◎ ◎ Example 12 ◎ ◎ ◎ ◎ ◎ Example 13 ◎ ◎ ◎ ◎ ◎ Example 14 ◎ ◎ ◎ ◎ ◎ Comparative Example 1 ◎ ◎ ◎ △ × Comparative Example 2 ◎ ◎ ◎ ◎ × Comparative Example 3 ◎ ◎ ◎ × ◎

As shown in Table 2, the coated steel sheets of Examples 1 to 14 using the composite resin coating compositions falling within the scope of the present invention are excellent in corrosion resistance and fuel resistance, Weldability and anti-moldability are also excellent.

However, it can be seen that the steel sheets of Comparative Examples 1 to 3 which do not contain the metal nano powder and / or the repellent compound exhibit a low level of core weldability and / or antifungal property, so that they are used in fuel tanks using biofuels It can be seen that it is unsuitable to be.

Specifically, as shown in FIG. 2, Examples 2, 5, 11, and 14 using a composite resin coating composition falling within the scope of the present invention have a welding current range of 2 kA or more at a seam welding speed of 6 mpm, Can be seen.

In addition, regarding the anti-fungal properties, the composite resin coating compositions used in Examples 1 to 14 described above contain a very small amount of a repellent compound, but due to the porous compound used, the repellent compound floats on the surface of the coating film And exhibits excellent antifungal properties.

However, it can be seen that the steel sheets of Comparative Examples 1 to 3, which do not contain metal nano powder and / or repellent compound, exhibit low levels of core weldability and / or antifungal property. Especially, as shown in FIG. 2, The welding current range is 0.7kA at the welding speed, and the weldability is very low. Therefore, it can be seen that the steel sheets of Comparative Examples 1 to 3 are unsuitable for use in a fuel tank using biofuel.

On the other hand, the steel sheet coated with the composite resin coating composition of Examples 1 to 14 exhibited 100% performance in evaluating antifungal property after being left at high temperature and high humidity (60 DEG C, 95% relative humidity) for 4 months I could confirm it further. Accordingly, from the above results, it is predicted that the repellent compound incorporated into the porous compound can exhibit stable antifungal properties even after a long period of time, for example, for at least 10 years.

On the other hand, the composite resin coating compositions prepared in Examples 1 to 14 were rolled-coated onto a hot-dip galvanized steel sheet (GI, single side coated amount 60 ± 5 g / m ² ) instead of the galvannealed zinc- And then dried at a PMT of 170 DEG C and then cooled to produce a composite resin-coated steel sheet. The evaluated quality was the same as the quality of the composite resin-coated steel sheet using the galvannealed steel sheet.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be obvious to those of ordinary skill in the art.

1: Substrate
2: Plating layer
3: composite resin coating layer
4: a repellent compound incorporated into a porous compound

Claims (17)

Based on 100 parts by weight of an acryl-modified urethane resin, 5 to 40 parts by weight of a melamine curing agent; 1 to 10 parts by weight of a wetting agent; 1 to 15 parts by weight of a crosslinking agent; 1 to 3 parts by weight of a metal nano powder; 0.001 to 0.1 part by weight of a pyrethroid compound; And 2 to 5 parts by weight of a porous compound.
delete The composite resin coating composition according to claim 1, wherein the composite resin coating composition further comprises a solvent such that the solid content thereof is 3 to 30% by weight.
delete The composite resin coating composition according to claim 1, wherein the acryl-modified urethane resin has a number average molecular weight of 2,000 to 20,000.
The composite resin coating composition according to claim 1, wherein the melamine curing agent is at least one selected from the group consisting of melamine, butoxymethyl melamine, hexamethoxymethyl melamine, and trimethoxymethyl melamine.
The composite resin coating composition according to claim 1, wherein the wetting agent is at least one selected from the group consisting of tributyl phosphate, tricresyl phosphate and n-butyl phosphoric acid.
The method of claim 1, wherein the crosslinking agent is selected from the group consisting of gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropylmethyldiethoxysilane, gamma-aminopropyltrimethoxysilane, gamma-aminopropyltriethoxysilane, At least one compound selected from the group consisting of aminopropylmethyldimethoxysilane, isopropyldithiethanolaminotitanium, lactic acid titanium chelate, titanium acetylacetonate, isopropyldithiethanolaminozirconium, lactic acid zirconium chelate and zirconium acetylacetonate. Resin coating composition.
The composite resin coating composition according to claim 1, wherein the average particle diameter of the metal nano powder is 10 to 500 nm.
The composite resin coating composition according to claim 1, wherein the metal nanopowder comprises at least one metal selected from the group consisting of Ag, Al, Au, Co, Cu, Mo, Ni, Pd, W and Zn or an alloy thereof.
The pyrethroid compound according to claim 1, wherein the pyrethroid compound is selected from the group consisting of Allethrins, Bifenthrin, Bioallethrin, Cyfluthrin, Cyhalothrin, Such as Cypermethrin, Cyphenothrin, Deltamethrin, Empenthrin, Imiprothrin, Metofluthrin, Permethrin, Penotrin, Wherein at least one selected from the group consisting of Phenothrin, Pyrethrin, Resmethrin and Tetramethrin is at least one selected from the group consisting of Phenothrin, Pyrethrin, Resmethrin and Tetramethrin.
The method of claim 1, wherein the porous compound is selected from the group consisting of mesoporous silica; Alumina; And at least one metal oxide selected from the group consisting of niobium oxide, tantalum oxide, titanium oxide, zirconium oxide, cerium oxide and tin oxide.
The composite resin coating composition according to claim 3, wherein the solvent is at least one selected from the group consisting of water, methanol, ethanol, propanol, butanol, pentanol, phenol, hexanol and cyclohexanol.
A composite resin-coated steel sheet comprising a coating layer formed on at least one of both sides of a base steel sheet, the composite resin coating composition according to any one of claims 1, 3 and 5 to 13.
15. The method of claim 14 wherein the coating layer is a composite resin-coated steel sheet will be formed is coated with a coating weight of the composite resin coating composition from 0.1 to 2.5 g / m ^2.
15. The composite resin-coated steel sheet according to claim 14, wherein the coating layer has a thickness of 0.3 to 2 mu m.
The composite resin-coated steel sheet according to claim 14, wherein the steel sheet is a galvanized steel sheet, a hot-dip galvanized steel sheet, or a galvannealed (GA) steel sheet.

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