JP2018527466A - Composition for surface treatment of single-sided plated steel sheet, steel sheet surface-treated using the same, and surface treatment method using the same - Google Patents

Abstract

The present invention relates to a composition for surface treatment of a single-sided plated steel sheet, a steel sheet surface-treated using the same, and a surface treatment method using the same. Specifically, the surface treatment composition includes an acrylic-urethane copolymer resin (A); a Si—Zr—Ti organic-inorganic hybrid (hybrid) additive (B); and a solvent. 1 and 2 are satisfied.
[Formula 1] 0.3 <[A] / ([A] + [B]) <0.7
[Formula 2] 20% by weight <[A] + [B] <70% by weight
(In the above formulas 1 and 2, [A] and [B] are the content (% by weight) of A and the content (% by weight) of B with respect to the total amount (100% by weight) of the composition for surface treatment, respectively. ) Means.)

Description

  The present invention relates to a composition for surface treatment of a single-sided plated steel sheet, a steel sheet surface-treated using the same, and a surface treatment method using the same.

  Steel plates used in the fuel tanks of vehicles such as automobiles and motorcycles are the main components that are directly connected to the safety of the vehicle, and basically have a certain level of strength and durability, but also have corrosion resistance to fuel, fuel tanks, and others. It is necessary to ensure a certain level of quality such as weldability to prevent a fuel leak from leaking from the joint portion to which the secondary material is connected.

  In the past, as one of the methods for improving the quality of steel plates, plating methods for heavy metal substances such as lead (Pb), tin (Sn), and chromium (Cr) have been actively studied. However, in the recent situation where these heavy metal substances are regulated as environmental pollutants, it is inappropriate to study further.

  On the other hand, a coating method using an organic resin is known as another method for improving the quality of a steel plate. However, in order to ensure corrosion resistance, there is a problem that the weldability is rather deteriorated by coating to an excessively thick thickness or inevitably post-processing with a non-conductive material.

  The problems pointed out above are solved by the composition for surface treatment of a single-sided plated steel sheet, the steel sheet surface-treated using the same, and the surface treatment method using the same, which are provided in an implementation example of the present invention.

Composition for surface treatment of single-sided plated steel sheet In one embodiment of the present invention,
An acrylic-urethane copolymer resin (A); a Si-Zr-Ti organic-inorganic hybrid additive (B); and a solvent;
A composition for surface treatment of a single-sided plated steel sheet that satisfies the following formulas 1 and 2 is provided, and an explanation regarding such a composition for surface treatment is as follows.

[Formula 1] 0.3 <[A] / ([A] + [B]) <0.7
[Formula 2] 20% by weight <[A] + [B] <70% by weight
(In the above formulas 1 and 2, [A] and [B] are the content (% by weight) of A and the content (% by weight) of B with respect to the total amount (100% by weight) of the composition for surface treatment, respectively. Means)
First, the Si-Zr-Ti-based organic-inorganic hybrid (B) additive (B) includes a silicon (Si) -based material, a zirconium (Zr) -based chelating agent, a titanium (Ti) -based chelating agent, and a neutralizing agent. It may be a chelate compound formed by the above reaction.

  At this time, the silicon (Si) -based material may be one selected from silicon (Si) -based materials including colloidal silica, silica sol, and silicate, or a mixture of two to three types.

  The zirconium (Zr) -based chelating agent is one selected from zirconium (Zr) -based chelating agents including zirconium alkoxide, zirconium acylate, and tetraalkyl zirconate. Or a mixture of two or three kinds.

  The titanium (Ti) -based chelating agent includes hexafluorotitanic acid, titanium hydrofluoric acid, titanium oxide, titanyl nitrate, titanyl sulfate, and titanyl sulfate. Titanium Tetrachloride, Tetrabutyl titanic acid, Hexafluoroammonium Titanate, and Titanium Alkoxide containing titanium (Ti) based chelating agents 1 type, or a mixture of 2 to 3 types.

  The neutralizing agent may be one kind selected from amine compounds including isopropylamine and triethylamine, or a mixture of two to three kinds.

  On the other hand, the acrylic-urethane copolymer resin (A) may be a block copolymer of an acrylic resin and a urethane resin.

  The acrylic-urethane copolymer binder resin is a block copolymer of an acrylic resin having a number average molecular weight of 500,000 to 1,500,000 and a urethane resin having a number average molecular weight of 5,000 to 15,000. The copolymerization ratio of the acrylic resin in the acrylic-urethane copolymer binder resin may be 40 to 60% by weight.

  Meanwhile, the surface treatment composition may further include a coupling agent, an adhesion promoter, or a mixture thereof.

  The coupling agent includes gamma-glycidoxypropyltriethoxysilane, gamma-aminopropyltriethoxysilane, g-aminopropyltriethoxysilane, tetraethoxysilane, and tetraethoxysilane. One or two or more selected from silane-based coupling agents including methoxysilane (methyl trimethylsilane) and 3-glycidoxypropyltrimethoxysilane (3-Glycoxypropyltrimethylsilane) It may be a mixture.

  Specifically, the surface treatment composition further includes the coupling agent, and the content of the coupling agent with respect to the total amount (100% by weight) of the surface treatment composition is: It may be 0.5 to 10% by weight.

  The adhesion promoter may be a phosphate ester, ammonium phosphate, or a mixture thereof.

  Specifically, the composition for surface treatment further includes the adhesion promoter, and the content of the adhesion promoter relative to the total amount (100% by weight) of the composition for surface treatment is 2 to 20% by weight. There may be.

In another embodiment of the present invention, the surface-treated single-sided plated steel sheet ,
A single-side plated steel sheet; and a surface treatment layer;
The single-sided plated steel sheet includes a cold-rolled steel sheet and a first plating layer located on one side of the cold-rolled steel sheet,
The surface treatment layer is located on the first plating layer of the single-side plated steel plate and includes an acrylic-urethane copolymer resin (A) and a Si-Zr-Ti organic-inorganic hybrid (B) additive (B). A surface-treated single-side plated steel sheet that satisfies the following formula 1 is provided.

[Formula 1] 0.3 <[A] / ([A] + [B]) <0.7
(In Formula 1, [A] and [B] mean the content (% by weight) of A and the content (% by weight) of B with respect to the total amount (100% by weight) of the surface treatment layer, respectively. )
Specifically, the surface treatment layer may be formed using the surface treatment composition described above. Hereinafter, the description regarding the said surface-treated single-sided plated steel plate except the description which overlaps with what was mentioned above is provided.

First, 300-2500 mg / m < ² > may be sufficient as the mass of the said surface treatment layer per single side | surface of the said single-sided steel plate.

The mass of the first plating layer per one side of the cold-rolled steel sheet may be 5 to 300 g / m ² .

  The first plating layer may include zinc, a zinc-based alloy, or a combination thereof.

Meanwhile, the single-side plated steel sheet further includes a second plating layer unavoidably present on the other side of the cold-rolled steel sheet, and the mass of the second plating layer per one side of the cold-rolled steel sheet is 10 mg / m. ^It may be ² or less (excluding 0 mg / m ² ).

In another embodiment of the present invention, the surface treatment method of the single-side plated steel sheet ,
Providing a single-sided plated steel sheet comprising a cold-rolled steel sheet and a first plating layer located on one side of the cold-rolled steel sheet;
Applying a surface treatment composition on the first plating layer of the single-side plated steel sheet; and curing the applied surface treatment composition to form a surface treatment layer;
The surface treatment composition includes an acrylic-urethane copolymer resin (A), a Si-Zr-Ti organic-inorganic hybrid additive (B), and a solvent, and satisfies the following formulas 1 and 2. A surface treatment method for a single-sided plated steel sheet is provided.

[Formula 1] 0.3 <[A] / ([A] + [B]) <0.7
[Formula 2] 20% by weight <[A] + [B] <70% by weight
(In the above formulas 1 and 2, [A] and [B] respectively represent the content (% by weight) of A and the content (% by weight) of B with respect to the total amount (100% by weight) of the surface treatment layer. means)
Specifically, the composition for surface treatment used in the surface treatment method for the single-sided plated steel sheet may be the same as described above. Hereinafter, the description regarding the surface treatment method of the said single-sided plated steel plate except the description which overlaps with what was mentioned above is provided.

  The step of applying the surface treatment composition on the first plating layer of the single-sided steel plate may be performed by a roll coating method, a spray method, or a dipping method.

  The step of curing the applied surface treatment composition to form a surface treatment layer may be performed in a temperature range of 130 to 250 ° C.

  Meanwhile, the step of preparing the single-sided plated steel sheet may be performed using a plating tank in which a current shielding device (edge mask) is located on one side.

  According to the embodiment of the present invention, a steel sheet surface-treated with a composition for surface treatment of a single-sided plated steel sheet has the advantage of being excellent in corrosion resistance and weldability while being environmentally friendly.

FIG. 1 schematically illustrates a surface-treated single-sided plated steel sheet according to one implementation of the present invention. FIG. 2 schematically shows a fuel resistance evaluation apparatus used in an evaluation example of the present invention. FIG. 3 schematically shows the whole process of single-side plating and surface treatment used in the embodiment of the present invention.

  The advantages and features of the invention and the manner in which they are achieved will become apparent with reference to the implementations described in detail below. However, the present invention is not limited to the implementations disclosed below, and may be in a variety of different forms, merely to provide a complete disclosure of the invention, The present invention is provided only for those who have ordinary knowledge in the technical field to which the present invention pertains, and that the present invention is defined only by the scope of the claims.

  Throughout the specification, when a part “includes” a component, this means that the component may further include other components, unless specifically stated to the contrary. To do.

Composition for surface treatment of single-sided plated steel sheet In one embodiment of the present invention,
An acrylic-urethane copolymer resin (A); a Si-Zr-Ti organic-inorganic hybrid additive (B); and a solvent;
A composition for surface treatment of a single-sided plated steel sheet that satisfies the following formulas 1 and 2 is provided.

[Formula 1] 0.3 <[A] / ([A] + [B]) <0.7
[Formula 2] 20% by weight <[A] + [B] <70% by weight
(In the above formulas 1 and 2, [A] and [B] are the content (% by weight) of A and the content (% by weight) of B with respect to the total amount (100% by weight) of the composition for surface treatment, respectively. Means)
The surface treatment composition does not contain heavy metal materials such as lead (Pb), tin (Sn), and chromium (Cr), and is environmentally friendly, but has excellent corrosion resistance due to the acrylic-urethane copolymer resin (A). It can be ensured, and the above-described problems can be solved by expressing the conductivity by the Si-Zr-Ti organic-inorganic hybrid additive (B).

  Specifically, in the surface treatment composition, the acrylic-urethane copolymer resin (A) and the Si-Zr-Ti organic-inorganic hybrid (hybrid) additive (B) are included as main components. These contents need to be controlled so as to satisfy the above formulas 1 and 2 simultaneously.

  In relation to the above formula 1, when the total content of A and B is 70% by weight or more with respect to the total amount (100% by weight) of the surface treatment composition, the solid content is excessive and for the surface treatment The stability of the composition may decrease, and the surface properties of the steel sheet surface-treated using the composition may deteriorate. On the other hand, when it is 10% by weight or less, there is a limit that it is difficult to ensure sufficient corrosion resistance.

  Further, in relation to the above formula 2, when the ratio of the content of A is 0.3 or less with respect to the total content of A and B in the surface treatment composition, sufficient corrosion resistance is ensured. However, the adhesion to a steel plate (specifically, a single-side plated steel plate) may be reduced. On the other hand, in the case of 0.7 or more, the electrical conductivity may decrease and the weldability may deteriorate.

  This fact is supported by the examples described later (when the above formulas 1 and 2 are satisfied simultaneously), comparative examples (when the above formulas 1 and / or 2 are not satisfied), and evaluation examples thereof.

  On the other hand, the composition for surface treatment is used for surface treatment of single-sided plating. Specifically, when the surface treatment composition is applied on a plated layer of a single-sided plated steel sheet and then baked and cured, a steel sheet having a plated layer and a surface-treated layer formed only on one side can be obtained.

  In the single-side plated steel sheet thus surface-treated, the single-sided plate and the surface-treated layer are excellent in corrosion resistance and weldability and are suitable for application as a fuel contact surface. In the case of the other side, the welding process is carried out by the surface treatment layer by performing no plating treatment or surface treatment except for the plating layer and surface treatment layer that are unavoidably formed during the formation and surface treatment of the fuel contact surface. There is an advantage that it is possible to prevent problems such as a decrease in welding strength and generation of fume.

  Hereinafter, the surface treatment composition will be described in detail, and a specific description of a surface treatment method using the composition and a single-side plated steel sheet surface-treated using the method will be described later.

  The acrylic-urethane copolymer resin (A) is a substance excellent in corrosion resistance and hydrophobicity, and may be a block copolymer of an acrylic resin and a urethane resin.

  At this time, the copolymerization ratio of the block copolymer may be 40:60 to 60:40 as a weight ratio of the acrylic resin to the urethane resin. If the ratio is less than 40:60 and the copolymerization ratio of the acrylic resin in the block copolymer is small, the conductivity may be low. On the other hand, when the copolymerization ratio of the acrylic resin in the block copolymer is excessive, such as 60:40 or more, the flexibility of the surface treatment layer decreases and the workability deteriorates.

  Specifically, the block copolymer is a block copolymerization reaction between an acrylic resin having a number average molecular weight of 500,000 to 1,500,000 and a urethane resin having a number average molecular weight of 5,000 to 15,000. It may be a block copolymer formed by.

  At this time, melamine can be used as a curing agent, and ethylene acrylic acid or an aziridine curing agent can be used as an auxiliary curing agent.

  More specifically, the block copolymer may produce a mixture of the urethane resin and the acrylic resin, and the mixing ratio of the mixture may match the copolymerization ratio. Further, 1 to 10 parts by weight of the melamine curing agent may be added and 2 to 15 parts by weight of the auxiliary curing agent may be added based on 100 parts by weight of the mixture.

  When the addition amount range of the melamine curing agent and the auxiliary curing agent is below the lower limit, the block copolymerization reaction occurs insufficiently, and when above the upper limit, the stability of the surface treatment composition is increased by the unreacted substance. It is taken into account that it decreases.

  Thereafter, irradiation with ultraviolet rays or heat induces a block copolymerization reaction, and as a result, the acrylic-urethane copolymer resin (A) can be obtained.

  On the other hand, the Si-Zr-Ti organic-inorganic hybrid additive (B) includes a silicon (Si) material, a zirconium (Zr) chelating agent, a titanium (Ti) chelating agent, and a neutralizing agent. It may be a chelate compound formed by the above reaction.

  Specifically, the silicon (Si) -based substance chemically reacts with the zirconium (Zr) -based chelating agent and the titanium (Ti) -based chelating agent (specifically, a chelate reaction) to form a compound. The neutralizing agent serves to form appropriate conditions for the reaction.

  The silicon (Si) -based material may be one or a mixture of two or three selected from silicon (Si) -based materials including colloidal silica, silica sol, and silicate.

  The zirconium (Zr) -based chelating agent is one kind selected from zirconium (Zr) -based chelating agents including zirconium alkoxide, zirconium acylate, and tetraalkylzirconate. Or a mixture of two or three kinds.

  The titanium (Ti) -based chelating agent includes hexafluorotitanic acid, titanium hydrofluoric acid, titanium oxide, titanyl nitrate, titanyl sulfate, and titanyl sulfate. Titanium Tetrachloride, Tetrabutyl titanic acid, Hexafluoroammonium Titanate, and Titanium Alkoxide containing titanium (Ti) based chelating agents 1 type, or a mixture of 2 to 3 types.

  The neutralizing agent may be one kind selected from amine compounds including isopropylamine and triethylamine, or a mixture of two to three kinds.

  For example, colloidal silica having a particle size of 5 to 50 nm is used as the silicon (Si) -based material, and hexafluorotitanic acid (Hexafluoro Titanic Acid) is added as the titanium (Ti) -based chelating agent to the zirconium (Si). Tetraalkylzirconate can be added as a (Zr) -based chelating agent to produce a mixture.

  The silicon (Si) -based material is 40 to 90 wt% with respect to the total amount (100 wt%) of the silicon (Si) -based material, the titanium (Ti) -based chelating agent, and the zirconium (Zr) -based chelating agent. %, The titanium (Ti) -based chelating agent may be included in an amount of 5 to 30% by weight, and the zirconium (Zr) -based chelating agent may be included in an amount of 5 to 30% by weight.

  The chelate reaction can be induced while adding 3 to 10 parts by weight of amine based on 100 parts by weight of such a mixture. However, when the amount of amine added is 3 parts by weight or less, basic conditions are difficult to form and precipitation may occur. On the other hand, when the addition amount of the amine is 10 parts by weight or more, the addition amount of the amine is excessively large, and the stability of the reaction solution may be lowered.

  Meanwhile, the surface treatment composition may further include a coupling agent, an adhesion promoter, or a mixture thereof.

  In the case of the coupling agent, the acrylic-urethane copolymer resin (A) and the Si-Zr-Ti-based organic-inorganic hybrid (Hybrid) additive (B) are induced to have a corrosion resistance. Can play a role in improving.

  For example, the coupling agent may be gamma-glycidoxypropyl triethoxysilane, gamma-aminopropyltriethoxysilane, g-aminopropyltriethoxysilane, tetraethoxysilane, xetylenethylene. One or two or three kinds selected from silane-based coupling agents including methyl trimethoxysilane and 3-glycidoxypropyltrimethoxysilane (methyltrimethoxysilane) and 3-glycidoxypropyltrimethoxysilane A mixture of the above may also be used.

  In the case of the adhesion promoter, it can play a role of improving adhesion with the plating layer, and may be, for example, phosphate ester, ammonium phosphate, or a mixture thereof.

  Specifically, the content of the coupling agent is 0.5 to 10% by weight independently of the total amount (100% by weight) of the surface treatment composition. The content may be 2 to 20% by weight. When the content is below the lower limit of each range, there is no effectiveness, and when the content is above the upper limit, the stability of the composition for surface treatment may be lowered.

  More specifically, the coupling agent may be gamma-glycidoxypropyltriethoxysilane, gamma-aminopropyltriethoxysilane, g-aminopropyltriethoxysilane, tetraethoxysilane. A silane-based coupling agent selected from Tetrahethoxysilane, methyltrimethoxysilane (methyltrimethoxysilane), and 3-glycidoxypropyltrimethoxysilane (3-Glycoxypropyltrimethylsilane), or one coupling agent selected from It may be a mixture of two or more.

  Further, the adhesion promoter may be a phosphate ester, ammonium phosphate, or a mixture thereof.

In another embodiment of the present invention, the surface-treated single-sided plated steel sheet ,
A single-side plated steel sheet; and a surface treatment layer 130;
The single-sided plated steel sheet includes a cold-rolled steel sheet 110 and a first plating layer 120 located on one side of the cold-rolled steel sheet,
The surface treatment layer 130 is located on the first plating layer 120 of the single-side plated steel plate, and includes an acrylic-urethane copolymer resin (A) and a Si-Zr-Ti organic-inorganic hybrid (hybrid) additive (B). The surface-treated single-sided plated steel plate 100 satisfying the following formula 1 is provided, and FIG. 1 schematically shows this.

[Formula 1] 0.3 <[A] / ([A] + [B]) <0.7
(In Formula 1, [A] and [B] mean the content (% by weight) of A and the content (% by weight) of B with respect to the total amount (100% by weight) of the surface treatment layer, respectively. )
Specifically, the surface treatment layer 130 may be formed using the surface treatment composition described above. Hereinafter, the description regarding the said surface-treated single-sided plated steel plate except the description which overlaps with what was mentioned above is provided.

First, 300-2500 mg / m < ² > may be sufficient as the mass of the said surface treatment layer 130 per single side | surface of the said single-sided steel plate. However, when it is less than 300 mg / m ² , the thickness of the surface treatment layer 130 becomes excessively thin, and it may be difficult to ensure corrosion resistance. On the other hand, if it exceeds 2500 mg / m ² , the surface treatment layer 130 may be excessively thick, resulting in poor weldability and poor adhesion to the plating layer.

Meanwhile, the mass of the first plating layer 120 per one side of the cold-rolled steel sheet may be 5 to 300 g / m ² . However, if it is less than 5 g / m ² , the thickness of the first plating layer 120 becomes excessively thin, and it may be difficult to ensure corrosion resistance. On the other hand, when the amount of deposit exceeds 300 g / m ² , there is a drawback that processability and economic efficiency deteriorate.

  At this time, the first plating layer 120 may include zinc, a zinc-based alloy, or a combination thereof. Specifically, the zinc-based alloy may be Zn—Ni, Zn—Mg, Zn—Al, or Zn—Al—Mg.

On the other hand, the single-sided plated steel sheet further includes a second plating layer (not shown) that inevitably exists on the other side of the cold-rolled steel sheet, and the second plated layer (see FIG. 10 mg / m ² or less (except 0 mg / m ² ) may be used.

  As mentioned above, when the first plating layer 120 is formed on one side of the cold-rolled steel sheet, the second plating layer (not shown) is inevitably formed on the other side, but intentionally formed. It is not what was done.

In another embodiment of the present invention, the surface treatment method of the single-side plated steel sheet ,
Providing a single-sided plated steel plate including a cold-rolled steel plate 110 and a first plating layer 120 located on one side of the cold-rolled steel plate 110;
Applying a surface treatment composition on the first plating layer of the single-side plated steel sheet; and curing the applied surface treatment composition to form a surface treatment layer 130;
The surface treatment composition includes an acrylic-urethane copolymer resin (A), a Si-Zr-Ti organic-inorganic hybrid additive (B), and a solvent, and satisfies the following formulas 1 and 2. A surface treatment method for a single-sided plated steel sheet is provided.

[Formula 1] 0.3 <[A] / ([A] + [B]) <0.7
[Formula 2] 20% by weight <[A] + [B] <70% by weight
(In the above formulas 1 and 2, [A] and [B] respectively represent the content (% by weight) of A and the content (% by weight) of B with respect to the total amount (100% by weight) of the surface treatment layer. means)
Specifically, the composition for surface treatment used in the surface treatment method for the single-sided plated steel sheet may be the same as described above. Hereinafter, the description regarding the surface treatment method of the said single-sided plated steel plate except the description which overlaps with what was mentioned above is provided.

  First, the step of preparing the single-sided plated steel sheet may be performed using a plating tank in which a current masking device is positioned on one side.

  Specifically, in the plating tank, current does not flow on one side where the current shielding device (edge mask) is located, and current flows only on the other side. When the cold-rolled steel sheet is put into the plating tank and operated, electroplating is induced only on one side where current flows.

  At this time, if the current shielding device is too close to the material steel plate to be plated (that is, the cold-rolled steel plate 110), the material steel plate and the current shielding device may be damaged. On the other hand, when the distance is excessively large, a current may flow through the edge of the side surface that is not intended for plating, and plating may be performed, which deteriorates the welding quality. Therefore, it is necessary to appropriately adjust the position of the material steel plate 110 to be plated in the current shielding device.

Meanwhile, the step of applying the surface treatment composition on the first plated layer 120 of the single-sided plated steel sheet may be performed by a roll coating method, a spray method, or a dipping method. Specifically, the surface treatment composition may be applied at a coating amount of 300 to 2500 mg / m ² on the first plating layer 120 of the single-side plated steel sheet by a roll coating method. This coating amount takes the above-mentioned contents into consideration.

  On the other hand, the step of curing the applied surface treatment composition to form the surface treatment layer 130 may be performed in a temperature range of 130 to 250 ° C. Specifically, the temperature range is based on a steel plate temperature (MT-Metal Temperature).

  If the temperature is lower than 130 ° C., the reaction between the acrylic-urethane copolymer resin (A) and the Si—Zr—Ti organic-inorganic hybrid (Hybrid) additive (B) becomes insufficient, and post-treatment (specifically Specifically, a part of the surface treatment layer may fall off during washing). On the other hand, when it exceeds 250 ° C., the curing reaction does not occur any more and only the heat loss can be increased.

  Hereinafter, examples relating to implementation examples of the present invention, comparative examples compared with the examples, and evaluation examples thereof will be described in detail. However, the following examples are merely illustrative of the present invention, and the content of the present invention is not limited by the following examples.

  Specifically, in the following examples and comparative examples, in common, (1) a surface treatment composition is produced, (2) a single-side plated steel sheet is produced, and (3) a surface treatment. Then, (4) the final surface-treated single-sided plated steel sheet was evaluated.

  In this connection, FIG. 3 generally shows the single-sided plating of (2) and the surface treatment process of (3) using the composition produced in (1).

  Referring to FIG. 3, after the cold-rolled steel sheet 110 is passed through a welding machine and a leveler, it is subjected to water washing and pickling, and then in the form of a horizontal cell. The single-side plating of (2) is performed by moving to a plating tank.

  At this time, a current shielding device (edge mask) is located on one side surface of the plating tank, and no current flows (Off-current) on the side surface, so that plating is not performed (Non-Plating). On the other hand, current flows on the other side surface (on-current), plating is performed (plating), and the first plating layer 120 is formed. At the same time, the second plating layer (not shown) is formed by partly plating the side surface where the current shielding device (edge mask) is inevitably located.

  The steel plate plated on one side in this way undergoes a post treatment process, then changes the strip direction (stripe reversal), moves to a roll coater (Coater), and performs the surface treatment process of (3) above. Do. At this time, only the surface of the first plating layer 120 can be treated using the composition produced in (1).

  Specifically, the composition on the surface of the first plating layer 120 is closed (Close), and the composition manufactured in (1) can be applied. At the same time, the roll on the surface where the second plating layer (not shown) is located may be opened (Open) so that the composition produced in (1) is not applied.

  Thereafter, the surface treatment layer 130 can be formed by curing the composition applied on the first plating layer 120 in an oven. Finally, the surface quality can be inspected and obtained as a product.

  Hereinafter, (1) to (4) will be described with reference to FIG.

(1) Production of Surface Treatment Composition According to Tables 1 to 3, acrylic-urethane copolymer resin (A), Si-Zr-Ti organic-inorganic hybrid (hybrid) additive (B), silane coupling ( A surface treatment composition satisfying the respective compositions was produced by mixing a coupling agent, an adhesion promoter, and water.

  Each raw material used at this time purchased and used each product already commercialized.

(2) Manufacture of single-sided plated steel sheet According to Tables 1 to 3, steel sheets plated on one side with zinc or a zinc-based alloy were manufactured.

  For zinc or zinc-based alloy plating, a pure zinc or zinc-based alloy plating composition plating solution was used. More specifically, zinc or a zinc-based alloy plating ingot is melted at a concentration of 40 to 120 g / L in a sulfuric acid bath whose temperature is controlled to 40 to 90 ° C. and pH 0.5 to 2. It is what was used.

Cold-rolled steel sheet (steel sheet rolled to a thickness of 0.4 to 2.3 mm at room temperature) is put into the plating tank, and the plating tank using the plating solution operates under a current density condition of 10 to 100 A / dm ^2. Then, electroplating is induced only on one side surface through which current flows, and target plating is performed only on one side of the cold-rolled steel sheet. The surface on which the target plating is performed in this manner is described as “fuel contact surface” in Table 2 below.

  However, an extremely small amount of plating was inevitably performed on the other surface of the cold-rolled steel sheet. The surface on which plating was inevitably performed in this way was described as “painted surface” in Table 2 below.

(3) Surface treatment of single-sided plated steel sheet After applying the surface treatment composition of (1) to the fuel contact surface of the single-sided plated steel sheet of (2) by using a roll coating method according to Tables 1 to 3 By baking and curing at 210 ° C., each surface-treated single-sided plated steel sheet was finally obtained.

(4) Evaluation of surface-treated single-sided steel sheet According to Tables 1 to 3, solution stability and corrosion resistance for the surface-treating composition of (1) or the surface-treated single-sided steel sheet of (3) The physical properties necessary for the fuel tank steel plate, such as fuel resistance and weldability, were evaluated. Specifically, the evaluation conditions for each physical property are as follows.

Solution stability : The surface treatment composition of (1) above was stored at room temperature for 60 days and at a temperature of 50 ° C. for 45 days, and then observed for the occurrence of precipitation or gelation in the composition. Evaluation was based on good, bad, and poor standards.

Corrosion resistance : Corrosion according to the following criteria after the surface-treated single-side plated steel sheet of (3) has passed through a flat plate state of 35 ° C. salt water (concentration 5%) at a spray pressure of 1 kg / cm ² for 500 hours. The area (area% of rust generated relative to the entire surface area%) was evaluated.

◎: When the corrosion area is almost 0 ○: When the corrosion area is 5 or less □: When the corrosion area is more than 5 and less than 30 △: When the corrosion area is more than 30 and less than 50 ×: When the corrosion area is more than 50
Fuel resistance: with fuel resistance evaluation apparatus of FIG. 2, was evaluated fuel resistance to degradation petrol and biodiesel respectively at high temperature conditions.

  Specifically, the fuel resistance evaluation for deteriorated gasoline is to produce a deteriorated gasoline solution (total volume of 100%) containing 78.58% by volume gasoline, 20% by volume ethanol, and 1.42% by volume pure water. After adding 100 ppm (= 100 mg / kg) formic acid and 100 ppm (= 100 mg / kg) acetic acid on the basis of the weight of the deteriorated gasoline solution (1 kg) and leaving it at 60 ° C. for 3 months, the corrosion state of the steel sheet Inspected.

  On the other hand, the fuel resistance evaluation for biodiesel is biodiesel solution containing 81 vol% light oil, 9 vol% bio (BIO) diesel, 5 vol% pure water, and 5 vol% methanol (total 100 vol%). ) And 20 ppm (= 20 mg / kg) of formic acid and 0.3 parts by weight of peroxide are added based on the weight of the biodiesel solution (1 kg or 100 parts by weight) at 85 ° C. for 3 months After standing, the corrosion state of the steel sheet was inspected.

  The corrosion state of each steel sheet was evaluated as follows based on the corrosion area (area% of rust generated relative to the entire surface area%).

◎: When the corrosion area is almost 0 ○: When the corrosion area is 5 or less □: When the corrosion area is more than 5 and less than 30 △: When the corrosion area is more than 30 and less than 50 ×: When the corrosion area is more than 50
Weldability: using an arc welder, KC-27 welding wire (diameter 1.2 mm), the atmosphere gas Ar-20% CO ₂ under current 95A, arc voltage conditions 15.9Volt, and welding speed 13.5mpm After welding, the state of the welded portion, sputtering, fume generation, strength, and the like were observed, and evaluated based on good weldability (◯), unweldable (x), and poor weld quality (r).

Evaluation Example 1: Evaluation based on the content of each component of the surface treatment composition According to the processes (1) to (3), the amount of zinc-nickel alloy plating deposited on one surface of the cold-rolled steel sheet is 30 g / m ^2. A plating layer was formed as described above, and 1000 mg / m ² of the surface treatment composition shown in Table 1 was applied thereon and baked and cured under the condition that the steel sheet temperature was 210 ° C. Then, quality evaluation was performed by said (4) and the result was recorded in Table 1.

  Referring to Table 1, the acrylic-urethane copolymer resin (A) and the Si-Zr-Ti organic-inorganic hybrid (hybrid) were added to the total amount (100% by weight) of each surface treatment composition. The content of the agent (B) satisfies the following formulas 1 and 2 simultaneously, the content of the coupling agent is 0.5 to 10% by weight, and the content of the adhesion promoter is 2 to 20% by weight. It can be seen that all physical property evaluation results are excellent only if the above is satisfied.

[Formula 1] 0.3 <[A] / ([A] + [B]) <0.7
[Formula 2] 20% by weight <[A] + [B] <70% by weight
Evaluation Example 2: Evaluation Based on the Amount of Plating Adhesion Through the processes (1) to (3), a zinc-nickel alloy plating layer is formed on one surface of a cold-rolled steel sheet with the amount of adhesion shown in Table 2, and a surface treatment composition is formed thereon The product was applied at 1000 mg / m ² and baked and cured under conditions where the steel plate temperature was 210 ° C. Then, quality evaluation was performed by said (4) and the result was recorded in Table 2.

Referring to Table 2, it can be seen that when the amount of plating adhesion on the fuel contact surface is 5 to 300 g / m ² and the amount of plating adhesion on the painted surface is 10 mg / m ² or less, all the physical property evaluation results are excellent. .

Evaluation Example 3: Evaluation by Content of Each Component of Surface Treatment Composition According to the processes (1) to (3), the amount of zinc-nickel alloy plating deposited on one side of a cold-rolled steel sheet is 30 g / m ^2. A plating layer was formed as described above, and a surface treatment layer was formed thereon under the conditions of steel plate temperature and adhesion amount shown in Table 3. Then, quality evaluation was performed by said (4) and the result was recorded in Table 3.

Referring to Table 3, the surface treatment layer adhesion amount on the fuel contact surface (that is, the coating amount of the surface treatment composition) is 300 to 2500 mg / m ^2, and the steel plate temperature is 130 to 250 ° C. It can be seen that all of the physical property evaluation results are excellent when bake hardened with.

  The embodiments of the present invention have been described above with reference to the accompanying drawings. However, those skilled in the art to which the present invention pertains may change the technical idea and essential features of the present invention. It will be understood that the invention can be implemented in other specific forms.

  Therefore, it should be understood that the embodiments described above are illustrative in all aspects and are not limiting. The scope of the present invention is defined by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and the equivalent concept thereof are described in the present invention. Should be construed as falling within the scope of

Claims (22)

Acrylic-urethane copolymer resin (A);
A Si—Zr—Ti based organic-inorganic hybrid additive (B); and a solvent;
A composition for surface treatment of a single-sided plated steel sheet that satisfies the following formulas 1 and 2.
[Formula 1] 0.3 <[A] / ([A] + [B]) <0.7
[Formula 2] 20% by weight <[A] + [B] <70% by weight
(In the above formulas 1 and 2, [A] and [B] are the content (% by weight) of A and the content (% by weight) of B with respect to the total amount (100% by weight) of the composition for surface treatment, respectively. Means) The Si-Zr-Ti organic-inorganic hybrid additive (B) is:
The surface treatment of a single-sided plated steel sheet according to claim 1, which is a chelate compound formed by a reaction of a silicon (Si) -based material, a zirconium (Zr) -based chelating agent, a titanium (Ti) -based chelating agent, and a neutralizing agent. Composition. The silicon (Si) -based material is
The composition for surface treatment of a single-sided plated steel sheet according to claim 2, wherein the composition is one type selected from silicon (Si) -based materials including colloidal silica, silica sol, and silicate, or a mixture of two to three types. The zirconium (Zr) -based chelating agent is
The surface of the single-sided steel plate of Claim 2 which is 1 type selected from the zirconium (Zr) type | system | group chelating agent containing a zirconium alkoxide, a zirconium acylate, and a tetraalkyl zirconate, or a mixture of 2-3 types. Treatment composition. The titanium (Ti) -based chelating agent is
Select from titanium (Ti) chelating agents including hexafluorotitanic acid, titanium hydrofluoric acid, titanium oxide, titanyl nitrate, titanyl sulfate, titanium tetrachloride, tetrabutyl titanate, ammonium hexafluorotitanate, and titanium alkoxide The composition for surface treatment of the single-sided plated steel plate according to claim 2, wherein the composition is one kind or a mixture of two to three kinds. The neutralizing agent is
The composition for surface treatment of a single-sided plated steel sheet according to claim 2, which is one kind selected from isopropylamine and an amine compound containing triethylamine, or a mixture of two to three kinds. The acrylic-urethane copolymer resin (A) is
The single-side plated steel sheet according to claim 1, which is a block copolymer of an acrylic resin having a number average molecular weight of 500,000 to 1,500,000 and a urethane resin having a number average molecular weight of 5,000 to 15,000. Composition for surface treatment. The copolymerization ratio of the block copolymer is
The composition for surface treatment of a single-sided plated steel sheet according to claim 7, wherein the weight ratio of the acrylic resin to the urethane resin is 40:60 to 60:40. The surface treatment composition is:
The composition for surface treatment of a single-sided plated steel sheet according to claim 1, further comprising a coupling agent, an adhesion promoter, or a mixture thereof. The coupling agent is
Selected from silane coupling agents including gamma-glycidoxypropyltriethoxysilane, gamma-aminopropyltriethoxysilane, tetraethoxysilane, methyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane The composition for surface treatment of a single-sided plated steel sheet according to claim 9, wherein the composition is one type or a mixture of two or more types. The surface treatment composition further includes the coupling agent,
The composition for surface treatment of a single-sided plated steel sheet according to claim 9, wherein a content of the coupling agent with respect to a total amount (100% by weight) of the surface treatment composition is 0.5 to 10% by weight. The adhesion promoter is
The composition for surface treatment of a single-sided plated steel sheet according to claim 9, which is a phosphate ester, ammonium phosphate, or a mixture thereof. The surface treatment composition further comprises the adhesion promoter.
The composition for surface treatment of a single-sided plated steel sheet according to claim 9, wherein the content of the adhesion promoter with respect to the total amount (100% by weight) of the surface treatment composition is 2 to 20% by weight. A single-side plated steel sheet; and a surface treatment layer;
The single-sided plated steel sheet includes a cold-rolled steel sheet and a first plating layer located on one side of the cold-rolled steel sheet,
The surface treatment layer is located on the first plating layer of the single-sided plated steel plate, and includes an acrylic-urethane copolymer resin (A) and a Si-Zr-Ti organic-inorganic hybrid additive (B). A surface-treated single-sided plated steel sheet satisfying 1.
[Formula 1] 0.3 <[A] / ([A] + [B]) <0.7
(In Formula 1, [A] and [B] mean the content (% by weight) of A and the content (% by weight) of B with respect to the total amount (100% by weight) of the surface treatment layer, respectively. ) The mass of the surface treatment layer per side of the single-sided plated steel sheet is
The surface-treated single-sided plated steel sheet according to claim 14, which is 300 to 2500 mg / m ² . The mass of the first plating layer per one side of the cold rolled steel sheet is
The surface-treated single-sided plated steel sheet according to claim 14, which is 5 to 300 g / m ² . The first plating layer includes
The surface-treated single-sided plated steel sheet according to claim 14, comprising zinc, a zinc-based alloy, or a combination thereof. The one-side plated steel sheet further includes a second plating layer present on the other one side of the cold-rolled steel sheet,
The mass of the second plating layer per one side of the cold rolled steel sheet is
The surface-treated single-sided plated steel sheet according to claim 14, which is 10 mg / m ² or less (excluding 0 mg / m ² ). Providing a single-sided plated steel sheet comprising a cold-rolled steel sheet and a first plating layer located on one side of the cold-rolled steel sheet;
Applying a surface treatment composition on the first plating layer of the single-side plated steel sheet; and curing the applied surface treatment composition to form a surface treatment layer;
The surface treatment composition includes an acrylic-urethane copolymer resin (A), a Si—Zr—Ti organic-inorganic hybrid additive (B), and a solvent, and satisfies the following formulas 1 and 2. Surface treatment method for single-sided plated steel sheet.
[Formula 1] 0.3 <[A] / ([A] + [B]) <0.7
[Formula 2] 20% by weight <[A] + [B] <70% by weight
(In the above formulas 1 and 2, [A] and [B] respectively represent the content (% by weight) of A and the content (% by weight) of B with respect to the total amount (100% by weight) of the surface treatment layer. means) Applying a surface treatment composition on the first plated layer of the single-sided steel plate;
The surface treatment method for a single-sided plated steel sheet according to claim 19, which is performed by a roll coating method, a spray method, or an immersion method. Curing the applied surface treatment composition to form a surface treatment layer;
The surface treatment method for a single-sided plated steel sheet according to claim 19, which is performed in a temperature range of 130 to 250 ° C. Preparing the single-sided plated steel sheet;
The surface treatment method for a single-sided plated steel sheet according to claim 19, which is performed using a plating tank in which a current shielding device is located on one side.

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