KR101196073B1 - Black resin composition for improved color, lubricity, formability, anti-corrosion, and appearance with lower thickness and surface-treated steel sheet by using the resin composition - Google Patents

Abstract

The present invention relates to a resin composition for surface treatment having improved blackness, lubricity, processability, corrosion resistance, and surface defects, and a steel sheet using the same, and more particularly, is synthesized by a condensation reaction of an acid component and a polyhydric alcohol. The thermosetting polyester resin containing 30-80 mol% of silver aromatic acid components, 5-40 mol% of aliphatic acid components, and 1-30 mol% of alicyclic acid components is used for the thinning of a resin layer by using as a resin composition for surface treatments. It relates to a steel sheet with improved blackness, lubricity, processability, corrosion resistance and surface defects by blocking the transfer effect.

Description

Black resin composition for improved color, lubricity, formability, anti-corrosion, and appearance with lower thickness and surface-treated steel sheet by using the resin composition}

The present invention relates to a black resin composition for surface treatment with improved blackness, lubricity, processability, corrosion resistance and surface defects, and a steel sheet using the same.

Recently, due to the competition for thinning of interior and exterior materials of consumer electronics products such as PDP, LCD, LED TV, etc., the interior and exterior materials are rapidly replaced by steel sheet materials from plastic injection moldings that have been used. In particular, in the case of the exterior material is applied to the resin coated steel sheet such as black resin steel sheet having a beautiful and colored surface in order to be mounted on the product immediately after the press processing without additional coating process.

The resin coated steel sheet is usually composed of a top coat, a bottom coat, a zinc plated steel sheet and a bottom coat. The top coat layer has a thickness of 10 to 50 μm, mainly composed of polyester resin and melamine resin, and the bottom coat layer is acrylic urethane ester. Resin has a thickness of 0.5 ~ 2.0 ㎛ as a main component.

This resin coated steel sheet can be applied as an exterior material immediately after press processing without additional coating process, and the top coat layer on the surface appearance is preferably black (blackness = 100-L *, L * = whiteness) to 75 ~ 98 level. Produces.

The color of the resin film is determined by the pigment property and the film thickness property mainly of carbon black. The more the black pigment component is added, the thicker the film is, the more it feels black by the absorption of light (improved blackness). Generally, when the blackness (100-L *) value is 80 or more, it is expressed as "real black". 80 to 50 are expressed as "black gray", and 50 or less is expressed as "grey". As a component of the pigment expressing blackness, the blackness of such a resin coated steel sheet is increased due to the compositional characteristics of the coating resin. Heat transfer can be divided into direct heat transfer through the object, tropical flow, and radiant heat. As the blackness increases, absorption / heat dissipation by radiant heat increases. In particular, in the field of back cover materials for video appliances, black (real black) is preferred because of the characteristics of "aesthetics" and "heat dissipation inside an image device."

The undercoat is mainly composed of an organic / inorganic composite coating layer composed mainly of an acrylic urethane ester component in order to increase the bonding force between the top coat layer and the raw material zinc metal. It is advantageous to reduce the thickness of the top coat layer in order to increase the productivity in the continuous process of producing resin coated steel sheet having such a structure, but as the thickness of the top coat layer (resin layer) becomes thinner, the zinc coated layer is transferred to the black resin surface. This causes a problem of poor blackness and corrosion resistance. In addition, workability may be degraded due to an increase in the surface friction coefficient, such as cracking when forming a product, and surface defects may be easily revealed due to a thinner coating layer during in-line work for producing coated steel sheet.

Accordingly, the present inventors have studied to improve the blackness, corrosion resistance, processability, and surface defects that occur as the top coat is thinned, and are synthesized by the condensation reaction of an acid component and a polyhydric alcohol, and the acid component is an aromatic acid component 30 to 80. This invention was completed by developing the black resin composition for surface treatment containing the polyester resin containing mol%, the aliphatic acid component 5-40 mol%, and the alicyclic acid component 1-30 mol%.

Accordingly, an object of the present invention is to provide a black resin composition for surface treatment and a steel sheet using the same, which have improved blackness and corrosion resistance, workability and surface defects by blocking the transfer effect due to the thinning of the resin layer.

In order to achieve the above object, the present invention is synthesized by the condensation reaction of an acid component and a polyhydric alcohol, the acid component is 30 to 80 mol% aromatic acid component, 5 to 40 mol% aliphatic acid component, and alicyclic acid Polyester resin comprising components 1 to 30 mol%; Black pigment; And a black resin composition for surface treatment containing a solvent.

In addition, the steel sheet including the coating layer using the black resin composition for surface treatment is another feature.

In addition, an electronic product including the steel sheet is another feature.

The steel sheet made of the black resin composition according to the present invention can realize the desired blackness even when the resin layer is thinned, improves corrosion resistance and processability, improves surface lubricity, and can occur during high speed drying and high speed curing. Surface defect problems can be minimized.

Hereinafter, the present invention will be described in detail.

In the present invention, the term `` blackness '' is to quantify the degree of blackness of the coated film, the white light is incident on the resin surface and the wavelength of the reflected light is analyzed to quantify the degree of reflection / absorption of the wavelength to 1-100. Refers to the value represented (usually denoted by L *). If L * = 100, it means completely white. If L * = 0, it means completely black. The degree of blackness can be designated as 100-L *.

The present invention is synthesized by the condensation reaction of an acid component and a polyhydric alcohol, the acid component comprising 30 to 80 mol% of an aromatic acid component, 5 to 40 mol% of an aliphatic acid component, and 1 to 30 mol% of an alicyclic acid component. Polyester resin to be used; Black pigment; And a black resin composition for surface treatment containing a solvent.

If the aromatic acid component content is less than 30 mol%, there is a problem of poor corrosion resistance, and if it exceeds 80 mol%, workability is poor. In addition, when the content of the aliphatic acid component is less than 5 mol%, workability is poor, and if it exceeds 40 mol%, there is a problem of poor corrosion resistance. In addition, when the content of the cycloaliphatic acid component is out of the above range, workability and corrosion resistance are poor.

The aromatic acid component may be one or more selected from the group consisting of phthalic anhydride, terephthalic acid and isophthalic acid, but is not limited thereto. In addition, the aliphatic acid component may be one or more selected from the group consisting of adipic acid, succinic acid, azelaic acid, and sebacic acid, but is not limited thereto. In addition, the alicyclic acid component may be at least one selected from the group consisting of 1,4-cyclohexane dicarboxylic acid, hexahydro phthalic anhydride, and tetrahydro phthalic anhydride, but is not limited thereto.

The polyhydric alcohol may include 60 to 80 mol% of ethylene oxide added bisphenol A and 20 to 40 mol% of polyhydric alcohol, and when the ethylene oxide added bisphenol A is less than 60 mol%, there is a problem of decreasing corrosion resistance and chemical resistance. When it exceeds 80 mol%, there is a problem that workability and coating film adhesion decrease. The polyhydric alcohol is a dihydric alcohol except for ethylene oxide addition bisphenol A, specifically 1,4-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,6-hexanediol, propylene glycol , Diethylene glycol, methylpropanediol, neopentyl glycol, 1,4-cyclohexane anhydride and the like. The reason for excluding the trifunctional alcohol from the alcohol components is to prevent gelation due to the increase in viscosity at the end of the reaction, and the use of the alcohol of the trifunctional group having a steric shape for the synthesis of linear high polymers is unreasonable.

In particular, the ethylene oxide added bisphenol A is more preferably a structure in which 1 mol of bisphenol A and 4 to 6 mol of ethylene oxide are addition-polymerized.

The polyester resin has an acid value of 5 mgKOH / g or less (preferably 0.1 to 5 mgKOH / g) and a base of 5 to 20 mgKOH / g. If the base value is more than 20 mgKOH / g, the ester chain is not formed sufficiently, so that the molecular weight is low, which may lower the chemical resistance and corrosion resistance. In addition, if the base value is less than 5 mgKOH / g the color of the resin may be turbid at the end of the reaction and the resin viscosity rises, the paint dilution rate may be lowered during paint production. If the acid value exceeds 5 mgKOH / g, it may cause storage problems of resin and paint by unreacted acid.

The polyester resin preferably has a weight average molecular weight of 20,000 to 50,000 (preferably 20,000 to 35,000). If the weight average molecular weight is less than 20,000, the processability, chemical resistance and hardness are inferior, and if the weight average molecular weight is more than 50,000, the compatibility with the solvent is lowered and the solids content of the paint is lowered, thereby reducing the high speed workability of the PCM line. For losing.

In the resin composition for surface treatment according to the present invention, a black pigment is used to implement a color of real black, and mainly carbon black is not limited thereto. In this case, the average particle size of the carbon black is mainly 2 to 1000 nm, preferably 10 nm to 100 nm, which is high when the particle size of the carbon particles is smaller than 2 nm, the oil absorption during the pigment dispersion operation is dispersed This is because the amount of the resin and the dispersant is too large to show the effect of reducing the blackness, and if it exceeds 1000 nm, the size of the carbon particles is large and it is difficult to achieve the desired blackness.

The carbon black includes 0.1 to 25 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the polyester resin, which is difficult to obtain blackness of real black when used in an amount of less than 0.1 parts by weight, and 25 parts by weight. This is because when the excess amount is used, the content of other additives other than blackness is excessively reduced, so that it is difficult to realize physical properties such as coating film adhesion and corrosion resistance.

In addition to the black pigment, an organic pigment, an inorganic pigment, and the like may be additionally used, and any pigment used in the art may be used.

The black resin composition for surface treatment according to the present invention more preferably uses a mixed solution of a solvent having a boiling point (bp) of 100 to 180 ° C. and a solvent having a boiling point of 181 to 240 ° C. in order to realize coating workability. This is because, when the solvent is used alone, work stability such as fluidity and defoaming force of the paint is inferior, and a sudden boiling phenomenon during high-speed drying or high-speed curing may cause defects such as paping on the surface of the coating film.

The solvent having a bp of 100 to 180 ° C. may be at least one selected from the group consisting of cyclohexane, sorbose 100, toluene, xylene, 1-methoxy-2-propanol, cyclohexanone, and normal butanol, but is not limited thereto. Do not. The solvent having a bp of 181 to 240 ° C. is one selected from the group consisting of butyl carbitol, dibasic ester, benzyl alcohol, ethyl benzoate, dimethyl aniline, dibutyl sulfoxide, aniline, 1-octanol and 1-haptanol. It may be more than, but is not limited thereto.

The solvent is preferably used 30 to 90 parts by weight based on 100 parts by weight of the polyester resin, when less than 30 parts by weight may not only be excessively high coating thickness during coating due to the high viscosity, but also not completely cured Hardening may occur, and when it is more than 90 parts by weight, it is difficult to sufficiently secure the coating film due to the low viscosity, and too much solvent may be volatilized to cause environmental pollution.

The black resin composition for surface treatment according to the present invention may be added with a wax in order to further improve the surface lubricity during processing of the surface-treated steel sheet, the wax is 0.01 to 20 parts by weight, preferably 100 parts by weight of the polyester resin Preferably it contains 1 to 10 parts by weight, because when added to less than 0.01 parts by weight can not secure the desired lubricity, when added to more than 20 parts by weight is due to the heat film coating adhesion.

The wax may be a synthetic polymer wax, such as polyethylene, polypropylene, polytetrafluoroethylene, monoamide, bisamide, etc., depending on the formation method, or purified wax, for example, paraffin, microcrystalline wax, Fisherthrops wax ( Polymethylene) and the like, or natural extract waxes such as carnauba, lanolin, biswax, candelilla, and the like, but may include one or more.

In addition, the black resin composition for surface treatment of the present invention may further include at least one additive such as a wetting agent, a crosslinking agent, a lubricant, an antifoaming agent, a curing agent, an adhesion promoter, an acid catalyst, a quencher, a dispersion stabilizer, and the polyester resin. 5 to 80 parts by weight may be used based on 100 parts by weight.

The present invention also relates to a steel sheet comprising a coating layer containing a cured product of the black resin composition for surface treatment.

The steel sheet means a metal used for the purpose of automobile materials, home appliances, building materials, and the like, specifically, a metal such as an iron plate, and may be any steel sheet commonly used in the art for this purpose. Cold rolled steel sheet; Galvanized electroplated steel sheets such as galvanized steel sheets, zinc-nickel-plated steel sheets, zinc-iron-plated steel sheets, zinc-titanium-coated steel sheets, zinc-magnesium coated steel sheets, zinc manganese-coated steel sheets and zinc- Hot - dip galvanized steel; Aluminum-plated steel sheet; A plating steel sheet containing a different metal or an impurity such as cobalt, molybdenum, tungsten, nickel, titanium, aluminum, manganese, iron, magnesium, tin or copper in these plating layers; A coated steel sheet in which inorganic substances such as silica and alumina are dispersed in these plating layers; Or an aluminum alloy plate to which silicon, copper, magnesium, iron, manganese, titanium, zinc or the like is added; Or galvanized steel sheet coated with phosphate; Alternatively, a hot rolled steel sheet may be used, and a multilayer plated sheet obtained by sequentially treating two or more kinds during the plating may be used as necessary.

The method of treating the steel sheet using the black resin composition for surface treatment of the present invention may be carried out after washing the surface of the steel sheet by a method generally known in the art in order to remove oil and stains attached to the steel sheet as necessary. Can be. Although washing | cleaning is not limited to this, It can carry out using an alkali degreasing agent, an acidic degreasing agent, high temperature water, a solvent, etc. After cleaning, surface adjustment can be performed using acid or alkali.

It is preferable to wash with water after washing so that the cleaning agent does not remain on the surface of the steel sheet as much as possible when cleaning the surface of the steel sheet. Although not limited to this, As an example, it is preferable to surface-treat with the black resin composition for surface treatments of this invention, after wash | cleaning, water washing, and surface adjustment of the raw material metal (steel plate) surface as mentioned above.

In treating the metal surface by the method according to the present invention, the black resin composition for surface treatment can be applied as a coating layer on the surface of the steel sheet by any coating method generally known in the art. The coating method used in the application is not particularly limited, and known coating methods such as bar coating, dip coating, roll coating, curtain coating, spray coating, slit coating, gravure coating, and the like can be used. At this time, the coating temperature is not particularly limited.

The coating layer has an adhesion amount of 100 to 10,000 mg / m ² , preferably 1,000 to 8,000 mg / m ² . If the adhesion amount exceeds 10,000 mg / m ² , the price of the surface-treated steel sheet is too expensive, and if it is less than 100 mg / m ^{2, the} corrosion resistance and workability are greatly reduced, making it difficult to use for home appliance parts. In addition, the thickness of the coating layer is preferably 0.1 to 10 ㎛.

After applying the black resin composition for surface treatment of this invention to the steel plate surface-treated in this way, it is dried at the temperature of 80-280 degreeC.

At this time, the higher the drying temperature shows a tendency to improve the corrosion resistance of the resin layer, but if it exceeds 280 ℃ the resin is deteriorated to secure the desired physical properties, if the 80 to 280 ℃ if it is difficult to meet the quality requirements of the customer none.

The steel sheet thus treated has improved blackness, workability, lubricity, corrosion resistance, surface defects, and the like.

The present invention also includes an electronic product including the surface-treated steel sheet.

Hereinafter, the present invention will be described in more detail by way of examples. It should be noted, however, that the following examples are illustrative of the invention and are not intended to limit the scope of the invention.

Manufacturing example  1: Manufacture of polyester resin 1

Compound 40 obtained by addition polymerization of 30 mol% of isophthalic acid, 10 mol% of adipic acid, 10 mol% of 1,4-cyclohexanedicarboxylic acid, 1 mol of bisphenol A and 4 mol of ethylene oxide to use a polyester polymer resin mol mol, 10 mol% of 1,4-butylene glycol was prepared in a circular flask by passing through nitrogen and reacting at 115 ℃. The prepared polyester polymer resin had an acid value of 2.5 mgKOH / g, a base value of 15.0 mgKOH / g, and a weight average molecular weight of 22,450.

Manufacturing example  2: Manufacture of polyester resin 2

40 mol% of terephthalic acid, 15 mol% of azelaic acid, 5 mol% of hexahydro phthalic anhydride, 25 mol% of a compound obtained by addition polymerization of 1 mol of bisphenol A and 4 mol of ethylene oxide, and 15 mol% of 1,4-butylene glycol Using to prepare a polyester polymer resin in the same manner as in Preparation Example 1. The prepared polyester polymer resin had an acid value of 4.0 mgKOH / g, a base of 12.5 mgKOH / g, and a weight average molecular weight of 27,780.

Manufacturing example  3: Manufacture Mixed Solvent 1

In order to secure work stability by improving paint fluidity and defoaming ability, and to prepare a mixed solvent for minimizing surface defects during fast drying or fast curing, 50 parts by weight of Solvesso 100 and benzyl alcohol were mixed.

Manufacturing example  4: Preparation of Mixed Solvent 2

30 parts by weight of cyclohexanone, 25 parts by weight of normal butanol, and 45 parts by weight of benzyl alcohol were used, and the rest of the preparation conditions were the same as in Preparation Example 3 to prepare a mixed solvent.

Manufacturing example  5: Pigment Dispersion 1 Preparation

Carbon black pigments for achieving blackness of the black resin solution are difficult to achieve proper dispersion stability through direct agitation in the resin solution, and this non-uniform dispersion state is generally not suitable for achieving proper blackness of the pigment. Was prepared preliminarily and added to the remaining resin solution.

The pigment dispersion was prepared in 35 parts by weight of the resin of Preparation Example 1, Lubrizol dispersion agent, 15 parts by weight of Solsperse 32600, 10 parts by weight of carbon black N 500 (Korea carbon black, particle size 44 ± 4 nm), mixed solvent of Preparation Example 3. After adding alumina balls to 40 parts by weight, it was prepared by operating for 10 minutes at 3000 rpm in a ball mill.

Manufacturing example  6: Manufacture of pigment dispersion 2

A dispersion was prepared under the same condition as Preparation Example 5, but a dispersion was prepared using copeblack 890 (particle size 18 nm) of Columbian Chemical Co., Ltd. as carbon black.

Manufacturing example  7: Manufacture of pigment dispersion 3

A dispersion was prepared under the same conditions as in Preparation Example 5, except that the resin of Preparation Example 2 was used instead of the resin of Preparation Example 1.

Manufacturing example  8: Pigment Dispersion 4 Manufacture

A dispersion was prepared under the same conditions as Preparation Example 5, but was prepared using the solvent prepared in Preparation Example 4 instead of the solvent of Preparation Example 3.

[Steel Sheet Manufacturing]

Example  One

40 parts by weight of the polyester polymer resin of Preparation Example 1, 17 parts by weight of the pigment dispersion of Preparation Example 5, 5 parts by weight of the curing agent (Cytec industry, Cymel 325), 0.5 parts by weight of wax (Lubrizol, Lanco ™ Glidd 4832), antifoaming agent (EFKA , EFKA-2720) 1 part by weight, 0.5 parts by weight of acid catalyst (King industry, Nacure 1051), 3 parts by weight of adhesion promoter (Evonik Tego Chemie GmbH, Tego addid 230), 2 parts by weight of matting agent (Evonik Degussa, Aerosil R 7200) , 31 parts by weight of the mixed solvent of Preparation Example 3 was stirred at room temperature to prepare a black resin composition for surface treatment.

The resin composition for surface treatment was roll-coated so that the deposition amount of the dry coating film on the galvanized steel sheet was 1800 mg / m 2. Thereafter, the steel sheet was cured by induction heating for 10 seconds until the steel sheet temperature reached 230 ° C. to prepare a surface-treated steel sheet, which was used as a specimen in a physical property test [coating layer thickness: 2 μm].

Example  2

Steel sheet was prepared in the same manner as in Example 1, but the polyester polymer resin of Preparation Example 2 was used as the resin.

Example  3

A steel sheet was prepared in the same manner as in Example 1, but the pigment dispersion of Preparation Example 6 was used as the pigment.

Example  4

Steel sheet was prepared in the same manner as in Example 3, but the solvent of Preparation Example 4 was used as the solvent.

Example  5

Steel sheet was prepared in the same manner as in Example 4, but the pigment dispersion of Preparation Example 7 was used as the pigment.

Example  6

A steel sheet was manufactured in the same manner as in Example 5, except that the polyester polymer resin of Preparation Example 2 was used as the resin, and the pigment dispersion of Preparation Example 8 was used as the pigment.

Comparative example  One

A steel sheet was manufactured in the same manner as in Example 1, except that 10 mol% of isophthalic acid, 40 mol% of adipic acid, 5 mol% of 1,4-cyclohexanedicarboxylic acid, and bisphenol A were used to prepare a polyester polymer resin. 40 mol% of the compound to which 1 mol and 4 mol of ethylene oxides were addition-polymerized, and 5 mol% of 1, 4- butylene glycol were used. The prepared polyester polymer resin had an acid value of 4.4 mgKOH / g, a base of 7.8 mgKOH / g, and a weight average molecular weight of 19,400.

Comparative example  2

A steel sheet was manufactured in the same manner as in Example 1, except that 50 mol% of isophthalic acid, 1 mol% of adipic acid, 10 mol% of 1,4-cyclohexanedicarboxylic acid, and bisphenol A were used to prepare a polyester polymer resin. 35 mol% of the compound to which 1 mol and 4 mol of ethylene oxides were addition-polymerized, and 4 mol% of 1, 4- butylene glycol were used. The prepared polyester polymer resin had an acid value of 3.8 mgKOH / g, a base of 12.7 mgKOH / g, and a weight average molecular weight of 21,800.

Example  7

Steel sheet was prepared in the same manner as in Example 3, but iron oxide Black 444 (The Shepherd Color Co.) was used as a black pigment in preparing the pigment dispersion.

Example  8

Steel sheet was prepared in the same manner as in Example 4, but the wax content was changed to 0.001 parts by weight.

Example  9

A steel sheet was manufactured in the same manner as in Example 5, except that methyl cellosolve was used alone as a solvent component.

Example  10

A steel sheet was manufactured in the same manner as in Example 6, but 30 parts by weight of benzene, 40 parts by weight of ethyl acetate, and 30 parts by weight of cyclohexanone were used as a solvent component.

Test Example

The physical properties of the steel sheets prepared in Examples and Comparative Examples were measured by the methods given below.

1. Blackness Measurement

Konica Minolta Sensing Inc. The blackness was measured using CM-3700d (High-accuracy benchtop spectrophotometer), and evaluated according to the following criteria.

[Evaluation standard]

●: Blackness 70 or more

◐: Blackness 50 or more and less than 70

○: less than 50 black

2. Lubricity measurement

Surface friction coefficient was measured using UMT-2MT of Center for Tribology Inc. (CETR) USA and evaluated according to the following criteria.

[Evaluation standard]

○: coefficient of friction (μm) less than 0.25

Δ: friction coefficient (µm) 0.25 or more and less than 0.4

X: coefficient of friction (µm) 0.4 or more

3. Corrosion resistance measurement

The specimen was subjected to a salt spray test according to JIS-Z2371 for 144 hours, and the degree of rust was evaluated according to the following criteria.

[Evaluation standard]

○: less than 5% of white blue

(Triangle | delta): More than 5% of white rust less than 20%

×: 20% of white blue

4. Surface defect measurement

After hardening of the coated steel sheet, surface defects were visually observed under a microscope and evaluated according to the following criteria.

[Evaluation standard]

○: no visible defects when observed 10 times with the naked eye and microscope

(Triangle | delta): When it is observed visually, there is no outstanding defect, but when it is observed by magnifying under 10 times and a change of color or partial peeling is seen.

X: When a clear defect is seen upon visual observation

5. Workability Measurement

Workability measurement of the coated steel sheet was evaluated by the following criteria by performing 0T bending after coating and curing of the resin composition and observing the folded surface in an enlarged manner.

[Evaluation standard]

(Circle): When 0T banding and tape peeling after 0%, 10%, and 20% tension are all clean without a trace of a crack

(Triangle | delta): When there is no trace of a crack at 0T banding and tape peeling after 0% tension, but the trace of a partial crack is seen at 0T banding and tape peeling after 10% and 20% tension.

×: Partial crack or total peeling of the coating occurs when 0T banding and taping peeling occur after 0%, 10% and 20% tension

division Black degree Lubricity Corrosion resistance Surface defects Processability Example 1 ● ○ ○ ○ ○ Example 2 ● ○ ○ ○ ○ Example 3 ● ○ ○ ○ ○ Example 4 ● ○ ○ ○ ○ Example 5 ● ○ ○ ○ ○ Example 6 ● ○ ○ ○ ○ Comparative Example 1 ● ○ × △ ○ Comparative Example 2 ● ○ △ ○ × Example 7 ◐ ○ ○ ○ ○ Example 8 ● △ ○ ○ ○ Example 9 ● ○ ○ △ ○ Example 10 ● ○ ○ △ ○

As can be seen in Table 1, when preparing a polyester polymer resin in the composition of the black resin composition for surface treatment according to the present invention, the corrosion resistance of the coated steel sheet according to the addition ratio of the aromatic acid component and aliphatic acid component and It can be seen that the workability is affected, and the blackness is better implemented using carbon black. In addition, the use of the appropriate amount of wax was more excellent lubricity, as a solvent for high speed drying and curing surface defects when using a boiling point of 100 ~ 180 ℃ solvent and one or more of each of 181 to 240 ℃ solvent Could be minimized.

Claims (18)

Synthesized by condensation reaction of an acid component with a polyhydric alcohol, the acid component comprising 30 to 80 mol% of an aromatic acid component, 5 to 40 mol% of an aliphatic acid component, and 1 to 30 mol% of an alicyclic acid component Suzy; Black pigment; And solvents,
The polyester resin has a weight average molecular weight of 20,000 to 50,000, the black resin composition for surface treatment.
The method of claim 1,
The aromatic acid component is a black resin composition for surface treatment, characterized in that at least one selected from the group consisting of phthalic anhydride, terephthalic acid and isophthalic acid.
The method of claim 1,
The aliphatic acid component is a black resin composition for surface treatment, characterized in that at least one selected from the group consisting of adipic acid, succinic acid, azelaic acid and sebacic acid.
The method of claim 1,
The cycloaliphatic acid component is at least one selected from the group consisting of 1,4-cyclohexane dicarboxylic acid, hexahydro phthalic anhydride and tetrahydro phthalic anhydride black resin composition for surface treatment.
The method of claim 1,
The polyhydric alcohol is black resin composition for surface treatment, characterized in that it comprises 60 to 80 mol% of ethylene oxide addition bisphenol A and 20 to 40 mol% of polyhydric alcohol.
The method of claim 5, wherein
The ethylene oxide added bisphenol A is a black resin composition for surface treatment, characterized in that the addition polymerization of 1 mol of bisphenol A and 4 to 6 mol of ethylene oxide.
The method of claim 5, wherein
The polyhydric alcohols include 1,4-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,6-hexanediol, propylene glycol, diethylene glycol, methylpropanediol, neopentyl glycol and Black resin composition for surface treatment, characterized in that at least one selected from the group consisting of 1,4-cyclohexane anhydride.
The method of claim 1,
The polyester resin has an acid value of 5 mgKOH / g or less, and a base resin of 5 to 20 mgKOH / g.
delete The method of claim 1,
The black pigment is a black resin composition for surface treatment, characterized in that it comprises 0.1 to 25 parts by weight of carbon black with respect to 100 parts by weight of a thin polyester resin.
11. The method of claim 10,
The carbon black is a black resin composition for surface treatment, characterized in that the average particle size of 2 to 1000 nm.
The method of claim 1,
The solvent is a black resin composition for surface treatment, characterized in that the boiling point is a mixture of a solvent having a boiling point of 100 to 180 ℃ and a solvent having a boiling point of 181 to 240 ℃.
13. The method of claim 12,
The solvent having a boiling point of 100 to 180 ° C. is at least one selected from the group consisting of cyclohexane, sorbose 100, toluene, xylene, 1-methoxy-2-propanol, cyclohexanone and normal butanol. Black resin composition.
13. The method of claim 12,
The solvent having a boiling point of 181 to 240 ° C. is one selected from the group consisting of butyl carbitol, dibasic ester, benzyl alcohol, ethyl benzoate, dimethyl aniline, dibutyl sulfoxide, aniline, 1-octanol and 1-haptanol. The black resin composition for surface treatments characterized by the above.
The method of claim 1,
Black resin composition for surface treatment, characterized in that it further comprises 0.01 to 20 parts by weight based on 100 parts by weight of the polyester resin.
Steel sheet comprising a coating layer containing a cured product of the black resin composition for surface treatment according to claim 1.
17. The method of claim 16,
The thickness of the coating layer is a steel sheet, characterized in that 0.1 to 10 ㎛.
17. The method of claim 16,
The coating amount of the coating layer is a steel sheet, characterized in that 100 to 10,000 mg / m ² .