KR101008109B1 - Improved Chrome Free Resin Composition For Good Sustainability At High Humidity Or At High Temperature High Humidity Environment By Using The Resin Composition And The Surface Treating Method - Google Patents

Abstract

The present invention is a resin composition for treating the surface of the steel sheet, which has excellent corrosion resistance, alkali resistance, processability and conductivity, and chemical resistance, but does not contain any chromium component which is particularly excellent in heat resistance, high temperature and high humidity resistance, a method for producing a steel sheet using the same, and the preparation therefrom. To a finished surface treated steel sheet. The surface-treated steel sheet is at least one selected from the group consisting of a mixture of a soft urethane resin and a hard urethane resin as a resin composition, Ti or Zr organic oxide, monoaluminum phosphate, aluminum dihydrogen phosphate, first zinc phosphate, and hydrated manganese phosphate. It is prepared by coating a resin composition containing a phosphate compound, a water repellent, and a solvent on a steel sheet at 300 to 1,800 mg / m 2, and the obtained surface-treated steel sheet is excellent in corrosion resistance, conductivity and chemical resistance, in particular heat resistance, high temperature and high humidity resistance. Do.

Surface treatment steel, chrome free, heat resistance, high temperature and high humidity, water repellent

Description

Improved Chrome Free Resin Composition For Good Sustainability At High Humidity Or At High Temperature High Humidity Environment By Using The Resin Composition And The Surface Treating Method }

The present invention is particularly excellent in heat resistance, high temperature and high humidity resistance, and contains no chromium component excellent in corrosion resistance, conductivity and chemical resistance to a resin composition for surface treatment, a method for producing a steel sheet using the same and a surface-treated steel sheet prepared therefrom It is about.

Recently, with increasing interest in environmental issues around the world, the use of environmental pollutants, ie, Cr, Pb, Cd, Hg, PBB, PBDE, etc., is being tightened. In particular, the Restriction of Hazardous Substances (RoHS) implemented by the EU (Restriction of Hazardous Substances, implemented in 6.7.1), Waste from Electrical and Electronic Equipment (WE6.7 implemented), and new environmental regulations. Typical examples include the Registration, Evaluation and Authorization of Chemicals (REACH) and End-of-Life Vehicles (ELV) enforcement (7.1.1). It is demanding active response to new environmental management policies, such as development, reduction of waste in factories and green procurement.

Conventionally, galvanized steel sheet and zinc-based alloy plated steel sheet, aluminum plated steel sheet, aluminum alloy plated steel sheet, cold rolled steel sheet, hot rolled steel sheet, etc., which are used for automobile materials, home appliances, building materials, etc., are provided with corrosion resistance and paint adhesion. In order to do this, a surface treatment method of coating a chromate coating mainly composed of chromium on the surface has been generally performed. The main chromate treatments include electrolytic chromate and coated chromate. Among them, electrolytic chromate treatment is composed of hexavalent chromium as a main component, and in addition, a treatment solution containing various anions such as sulfuric acid, phosphoric acid, boric acid, and halogen is used. The method of cathodic electrolysis of a metal plate is performed generally. On the other hand, in the coating type chromate treatment, a method in which an inorganic colloid and an inorganic ion are added to a solution in which a part of hexavalent chromium has been reduced to trivalent beforehand is used to deposit a metal plate therein, or to spray a treatment solution onto the metal plate. It is carried out by.

When using these methods, due to the toxicity of hexavalent chromium contained in the chromate treatment solution, various measures are required in the working environment and drainage treatment, and recycling and disposal of automobiles, home appliances, building products, etc. using the surface treatment metals. Treatment also causes human health and environmental pollution. In addition, in the case of applying trivalent chromium, there is a problem that a part of the trivalent chromium is converted to hexavalent chromium by the ambient environment such as temperature or microorganisms.

Therefore, each steel company is focusing on developing a surface-treated steel sheet that does not contain hexavalent chromium and does not contain chromium that can satisfy various requirements such as corrosion resistance, alkali resistance and conductivity. Conventionally, after coating a metal salt film composed mainly of phosphate as a main component on the surface of a steel sheet, and then coating a resin based film composed mainly of acrylic, epoxy and urethane resin as a main component thereof, or manufacturing the secondary coating. The surface-treated metal steel sheet containing no chromium was prepared by forming a resin film and a secondary film, respectively.

However, the products often lower the electrical conductivity and weldability of the metal steel sheet according to the metal salt or the film thickness, which is not suitable for the use of electromagnetic wave suppression, internal noise suppression, and processability of copiers, printers, VCRs, and computers. There is this.

Also, in recent years, as most home appliances require surface-treated steel sheets that do not contain chromium having excellent conductivity, a coating steel sheet containing no chromium has been developed by coating only the first resin-based coating. However, unless the composition of the resin-based surface treatment composition is particularly excellent, there is a problem in that quality characteristics such as corrosion resistance are significantly lower than those of conventional chromium-treated or phosphate-treated base coated steel sheets. In recent years, however, major domestic and foreign home appliances manufacturers have established their own quality standards for materials and obtained quality certification for the development of environmentally friendly products for surface-treated steel sheets that do not contain chromium. I buy it.

Conventionally, a method of coating polyaniline on a metal plate as a coating method in consideration of conductivity without containing any hexavalent chromium is disclosed in Japanese Patent Laid-Open Nos. 8-92479 and 8-500770. However, since polyaniline having high rigidity and low adhesion exists between the metal and the resin film, the film can be easily peeled off at the polyaniline and metal interface and at the polyaniline and resin interface. Because of this, there is a problem when painting the steel sheet to give the design, more corrosion resistance and other functions. Low adhesion films are generally known to have low corrosion resistance. In addition, the solution stability is low, there is a lot of precipitates, a strong smell occurs, there is also a problem in the workability, such as overall work environment degradation. In addition, by using a method of coating only the first coating with a resin on the galvanized layer, it showed an excellent effect of improving the characteristics such as conductivity, corrosion resistance, alkali resistance, high temperature, high humidity, etc. There is a problem that the resin layer and the plating layer of the processing friction portion is damaged in part, so that the resin layer is lost or the surface becomes black.

In addition, US Patent Publication No. 2004-54044 discloses a composition in which an organic film former, a hexafluoro complex such as titanium and zirconium, at least one inorganic compound, and the like are mixed with water, but it contains a fluoride complex. This may affect the environment, and the solution is acidic, so care must be taken when handling.

In addition, Japanese Laid-Open Patent Publication No. 2002-030460 discloses a composition in which a vanadium compound is mixed with Zi and Ti in a mixed resin, but the etching process of the surface of a steel sheet using an acidic solution is performed to reduce the vanadium compound and secure adhesion. There is a problem that must be accompanied.

In addition, Korean Patent Publication No. 2006-76953 discloses an organic resin and an inorganic binder composite using a silane coupling agent and the like, and discloses a surface treatment composition including a rust preventive agent and a metal chelating agent. There is a disadvantage to be prepared in advance. In addition, some products that require alkali resistance lacks alkali resistance, so that the resin layer is partially damaged when contacted with the alkaline solution, resulting in the loss of the resin layer or severe discoloration of the surface.

Further, Japanese Patent No. 3706518 discloses a resin composition containing a phosphate compound selected from organic resins, ammonium phosphate, sodium phosphate, and potassium phosphate, but the purpose of using these phosphate compounds is to form a passivation layer on the upper part of the steel plate to improve corrosion resistance. It is limited to playing a role.

One object of the present invention is to provide a metal surface treatment composition capable of providing a coating layer that does not contain chromium having excellent corrosion resistance, conductivity, chemical resistance, etc., in particular, heat resistance and high temperature and high humidity resistance.

Another object of the present invention is to provide a surface-treated steel sheet coated with the composition.

Another object of the present invention is to provide a method for producing a surface-treated steel sheet by forming a resin coating layer with a resin composition according to the present invention.

The object of the present invention is not limited to those mentioned above, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, the present invention provides a resin composition applied on a steel sheet and / or a galvanized layer, a method for producing a surface-treated steel sheet using the same and a surface-treated steel sheet produced by the above method. Specifically, the present invention,

As a first embodiment, a mixed urethane resin of a soft urethane resin and a hard urethane resin; Ti or Zr-based organic oxides; At least one compound selected from the group consisting of monoaluminum phosphate, aluminum dihydrogen phosphate, first zinc phosphate and hydrated manganese phosphate; Water repellents selected from potassium zirconium carbonate, ammonium zirconyl carbonate and mixtures thereof; And a solvent; a resin composition for surface treatment of a steel sheet, including

As a second embodiment, the resin composition is 10 to 90 parts by weight of the mixed urethane resin; 1 to 20 parts by weight of Ti or Zr-based organic oxide; 0.1 to 10 parts by weight of a compound selected from the group consisting of monoaluminum phosphate, aluminum dihydrogen phosphate, first zinc phosphate, and hydrated manganese phosphate; 0.5 to 20 parts by weight of a water repellent; a resin composition for surface treatment of a steel sheet, including

As a third embodiment, the mixed urethane resin is a resin composition for surface treatment of a steel sheet composed of 5 to 95% by weight of a soft urethane resin and 5 to 95% by weight of a rigid urethane resin,

As a fourth embodiment, the soft urethane-based resin is prepared from isophorene diisocyanate, adipic acid and polyhydric alcohol or from acrylic polyol and polyisocyanate, and for surface treatment of a steel sheet of polyurethane having a number average molecular weight of 5,000 to 300,000. Resin composition,

As a fifth embodiment, the polyhydric alcohol is a resin composition for surface treatment of a steel sheet selected from acryl polyol, polyester polyol, polyether polyol, polyolefin-based polyol or a mixture thereof,

As a sixth embodiment, the hard urethane-based resin is a polyurethane resin prepared from polycaprolactone polyol or polycarbonate polyol and diisocyanate, 4,4'-bis (ω-hydroxyalkyleneoxy) biphenyl and methyl-2. Resin composition for surface treatment of a steel sheet, which is selected from polyurethane resins prepared from 6-diisocyanate hexanoate, and polyurethane resins having acetal bonds, having a number average molecular weight of 200,000 to 2,000,000,

As a seventh embodiment, the hard urethane resin is a resin composition for surface treatment of a steel sheet having a Shore A hardness of 40 to 90,

As an eighth embodiment, the diisocyanate is a paraphenylene diisocyanate resin composition for surface treatment of a steel sheet,

In a ninth embodiment, the Ti or Zr organic oxide is titanium diisopropoxide bis (acetylacetonate), titanium ortho ester, titanium (IV) butoxide, titanium (IV) (triethanolaminato) isopropoxide Seeds, tetrakis (triethanolaminato) zirconium (IV), titanium (IV) 2-ethylhexoxide, titanium (IV) isopropoxide, zirconium (IV) bis (diethyl citrato) -dipropoxide or A resin composition for surface treatment of a steel sheet selected from a mixture of these,

As a tenth embodiment, the solvent is a resin composition for surface treatment of a steel sheet, which is water,

In an eleventh embodiment, the solvent is an alkali-based aqueous solution selected from alcohol solvents selected from ethanol, methanol, propanol, isopropanol and glycerol, amine compounds, N-methylpyrrolidone, sodium hydroxide, potassium hydroxide, sodium carbonate and ammonium hydroxide. Or a resin composition for surface treatment of a steel sheet further comprising a mixture thereof;

As a twelfth embodiment, a method of manufacturing a surface-treated steel sheet comprising the step of coating the resin composition on the upper steel sheet and then coated with an adhesion amount of 300 to 1,800 mg / m 2,

As a thirteenth embodiment, the method of manufacturing a surface-treated steel sheet further comprising the step of drying the steel sheet coated with the resin composition at a temperature of 120 ~ 200 ℃ PMT,

In a fourteenth embodiment, the plated or unplated steel sheet includes a resin coating layer, wherein the resin coating layer is coated with a coating weight of 300 to 1800 mg / m 2 after drying the resin composition on the steel sheet. to provide.

As described above, by coating the metal surface using the resin composition for surface treatment of the present invention, it is excellent in alkali resistance and corrosion resistance without containing chromium, and also excellent in workability, conductivity, solution stability, etc. Excellent heat resistance and high temperature and high humidity.

Hereinafter, the present invention will be described in detail.

1 schematically shows the structure of a resin coated steel sheet.

The present invention provides a mixture of a soft urethane resin and a hard urethane resin, at least one compound selected from the group consisting of a corrosion resistant curing agent composed of Ti or Zr organic oxide, monoaluminum phosphate, aluminum dihydrogen phosphate, first zinc phosphate and manganese hydrate hydrate, By coating a resin composition containing no chromium composed of a water repellent and a solvent on a plated or unplated steel sheet, it has excellent alkali resistance, processability, conductivity, corrosion resistance, chemical resistance, and the like, and particularly, excellent heat resistance and high temperature and high humidity resistance. It is related with the resin composition for surface treatment which can manufacture a metal steel plate.

In the resin composition of the present invention, a mixed urethane resin of the soft urethane resin and the hard urethane resin is used. Since the urethane resin has strong water resistance, chemical resistance, acid resistance and alkali resistance, and the coating film is soft and strong, It is used to prevent scratches on the surface by painting on steel sheets or aluminum plates, or widely used to impart chemical resistance.

The mixed urethane resin is preferably contained 10 to 90 parts by weight. If the solids content of the entire urethane resin is less than 10 parts by weight, the chemical resistance against the saline resistance of the urethane resin and the penetration of chemicals against the penetration of corrosion ions is not exhibited, and the chemical resistance and alkali resistance are lowered. For this reason, when degreasing at 60 ° C. for 5 minutes with an alkaline solution having a pH of 10 or more, there is a problem that the resin film is discolored or peeled off. If it exceeds 90 parts by weight, the solution stability due to entanglement is lowered and the price is increased. have.

However, since the urethane resin alone has a limit in realizing soft and strong properties, the present invention uses a mixed urethane resin in which a soft urethane resin and a hard urethane resin are mixed. The soft urethane resin is 5 to 95% by weight of the mixed urethane resin. If the flexible urethane resin is less than 5% by weight, the workability is improved, but heat resistance and water deterioration resistance are lowered, and if it exceeds 95% by weight, there is a problem in that the workability is not improved and corrosion resistance is greatly reduced.

In addition, the molecular weight of the soft urethane-based resin is preferably 5,000 to 300,000. If the molecular weight of the flexible urethane-based resin is less than 5,000, the workability is greatly lowered, if it exceeds 300,000, there is a problem that the stability of the solution is reduced.

The soft urethane-based resin is a polyurethane resin prepared from isophorene diisocyanate, adipic acid and polyhydric alcohol such as polyurethane dispersion resin, polyethylene modified polyurethane resin, and the like, and acrylic-urethane resin, polyethylene-acryl modified polyurethane resin, and the like. Polyurethane resins prepared from the same acrylic polyols and polyisocyanates can be used. Here, as said polyhydric alcohol, an acryl polyol, polyester polyol, polyether polyol, polyolefin polyol, etc. can be used.

Furthermore, the molecular weight of the hard urethane resin is preferably 200,000 to 2,000,000. If the molecular weight of the rigid urethane-based resin is less than 200,000, there is no effect of improving workability, and if the molecular weight exceeds 2,000,000, the stability of the solution decreases, and the viscosity of the resin solution rises, thereby degrading workability.

The hard urethane-based resin is a polycaprolactone polyol or polycarbonate polyol and a diisocyanate, in particular, a polyurethane resin prepared from paraphenylene diisocyanate, 4,4'-bis (ω-hydroxyalkyleneoxy) biphenyl and methyl Polyurethane resins prepared from -2,6-diisocyanate hexanoate, polyurethane resins having acetal bonds, and the like can be used.

In addition, the hard urethane-based resin is preferred to use a Shore (Shore) A hardness of 40 to 90 when manufacturing a dry film. If the Shore A hardness is less than 40, the workability is not improved. If the Shore A hardness is more than 90, the coating film becomes too hard and is crushed during processing. Therefore, it is preferable to have the hardness in the above range.

Ti or Zr organic oxide is added to the urethane resin as a corrosion resistant hardener. The corrosion resistant hardener includes 1 to 20 parts by weight of solid content concentration. At this time, if the content of the anti-corrosion hardener is less than 1 part by weight, the corrosion resistance is lowered and there is almost no effect of addition, and if it exceeds 20 parts by weight, the concentration is saturated, so that a large amount of precipitate is generated, and the solution stability is lowered. The problem is that Mars is reduced.

Examples of the Ti or Zr organic oxide include titanium diisopropoxide bis (acetylacetonate), titanium ortho ester, titanium (IV) butoxide, titanium (IV) (triethanolaminato) isopropoxide, tetra Kiss (triethanolaminato) zirconium (IV), titanium (IV) 2-ethylhexoxide, titanium (IV) isopropoxide, zirconium (IV) bis (diethyl citrato) -dipropoxide and the like. And at least one compound selected from them.

In addition, the resin composition for surface treatment of the steel sheet of the present invention contains one or more compounds selected from monoaluminum phosphate, aluminum dihydrogen phosphate, first zinc phosphate, manganese phosphate hydrate and the like. These materials are added to improve the adhesion between the resin and the steel sheet, in particular the galvanized layer, and can form a passive film on the zinc layer to improve the corrosion resistance and at the same time can be expected to improve the conductivity and heat resistance by the metal salt effect.

Compounds such as monoaluminum phosphate, aluminum dihydrogen phosphate, first zinc phosphate, and hydrated manganese phosphate are preferably added in a concentration range of 0.1 to 10.0 parts by weight. If these substances are added below 0.1 part by weight, the adhesion to the steel sheet is lowered, and resin peeling is more likely to occur in a process such as alkali degreasing, and when they are added in excess of 10.0 parts by weight, these materials do not improve the adhesion between the resin and the steel sheet. It is not preferable because it promotes the entanglement of the resin and inferior solution stability, and rather lowers the adhesion between the resin and the steel sheet.

The resin composition of the present invention includes a water repellent, and the water repellent may be used alone or in combination with potassium zirconium carbonate and ammonium zirconyl carbonate. These water repellents can use a commercially available thing. Specifically, Zirmel 1000 made by MEL Chemicals is mentioned as potassium zirconium carbonate, and Bacote 20 made by MEL Chemicals is mentioned as ammonium zirconyl carbonate.

These water repellents can be added in the range of 0.5-20 weight part in solid content concentration. At this time, if the concentration of the water repellent is less than 0.5 parts by weight, the hydrophobicity and corrosion resistance is lowered, and there is no desirable effect of improving the high temperature and high humidity resistance, and if it exceeds 20 parts by weight, the insolubility increases, the hydrophobicity is saturated and additional hydrophobicity is imparted. It does not contribute, and is not desirable for reasons such as a price increase.

In addition, the surface treatment composition of the present invention may further include one or more additives such as a wetting agent, a crosslinking agent, a lubricant, and an antifoaming agent. The wetting agent is effective in streaking and adhesion, the crosslinking agent in corrosion resistance and alkali resistance, the lubricant in friction coefficient and processability, and the antifoaming agent in further improving workability. These additives are preferably added in the range of 5 to 25 parts by weight. If the content of the additive is less than 5 parts by weight, there is no use effect of the additives such as corrosion resistance, alkali resistance, etc., if it exceeds 25 parts by weight, the effect is saturated, and further addition is not meaningful and there is a problem of reducing solution stability.

The wetting agent includes a deagglomerated wet dispersant, a polymer wet dispersant, and the like, and is specifically marketed by EFKA, Tego, Ciba, Bumwoo Chemical Co., Ltd., for example, EFKA 3580 (EFKA), BW- W500 (Bumwoo Chemical Co., Ltd.) or WET 500 (Ciba Co., Ltd.) etc. are mentioned.

Examples of the crosslinking agent include vinylsilane, methoxysilane, acrylicsilane, epoxysilane, chlorosilane, alkoxysilane, silazane, silylating agent, melamine, melamine resin, alkylmelamine, alkylmelamine resin, fluorinated melamine and fluorinated melamine resin, and polyamine type. , Alkylated aromatic polyamine-based, polyamide-based or acid-anhydride-based curing agents and the like can be used.

The lubricant includes silicone wax, polyethylene wax, polypropylene wax, amide wax, polytetrafluoroethylene (PTFE) wax, paraffin wax, and the like.

The antifoaming agent may be an oil type, a modified type, a solution type, a powder type, or an emulsion type silicone antifoaming agent.

The component except solid content in a resin composition is a solvent, and water can be used as a solvent. Furthermore, in order to improve the characteristics of wettability, dispersibility, etc. of a coating composition, an alcoholic solvent and an alkali aqueous solution can be further added. Examples of the alcohol solvent include ethanol, methanol, propanol, isopropanol, glycerol, and the like. The alkaline aqueous solution includes an amine compound, N-methylpyrrolidone, sodium hydroxide, potassium hydroxide, sodium carbonate, and ammonium hydroxide. Can be. The content of the solvent is included so that the solids content in the composition is from 5 to 25% by weight.

Since the resin composition particles of the corrosion resistant curing agent are uniformly reacted and dispersed in the organic functional group of the resin, the resin solution is excellent in stability and excellent in conductivity, alkali resistance and heat resistance of the anticorrosive coating layer, and further includes a water repellent agent. It shows an effect that is further improved in hydrophobicity, corrosion resistance and high temperature and high humidity resistance.

The deposition amount of the coating layer coated with the resin composition of the present invention is preferably 300 to 1,800 mg / m 2 as the deposition amount after drying, and the drying temperature (Peak Metal Temperature, PMT) is 120 ° C. to similar to the drying temperature of a conventional resin-based surface treatment liquid. 200 ° C. At this time, if the amount of adhesion after drying is less than 300 mg / m 2, there is no effect of improving the corrosion resistance and workability. In addition, the higher the drying temperature shows a tendency to improve the corrosion resistance of the resin film, 120-200 ℃ is not unreasonable to meet the customer's quality requirements.

In addition, the metal sheet to which the present invention can be applied is a zinc-based electroplated steel sheet such as a galvanized steel sheet, a zinc nickel plated steel sheet, a galvanized steel sheet, a zinc titanium plated steel sheet, a zinc magnesium plated steel sheet, a zinc manganese plated steel sheet, or a zinc aluminum plated steel sheet. , Hot-dip galvanized steel sheet, aluminum plated steel sheet, and also a plated steel sheet containing cobalt, molybdenum, tungsten, nickel, titanium, aluminum, manganese, iron, magnesium, tin, copper, etc., as dissimilar metals or impurities in these plating layers. In addition, plated steel sheets in which inorganic materials such as silica and alumina are dispersed in these plating layers, or aluminum alloy sheets containing silicon, copper, magnesium, iron, manganese, titanium, zinc, or the like, or galvanized steel sheets coated with phosphate, cold rolled steel sheets And hot rolled steel sheet. Moreover, it is applicable also to the multilayer plating board which processed two or more types sequentially during said plating.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited through the following examples.

[ Example  1-13 and Comparative example  1-11]

1-1. Preparation of Resin Composition

As a monomer, a soft urethane resin having a number average molecular weight of 100,000 was prepared from isophorene diisocyanate, adipic acid, and acrylic polyol monomer. As a monomer of a hard urethane resin, a hard urethane resin having a number average molecular weight of 1,000,000 and a 60 Shore A hardness was prepared from a paraphenylene diisocyanate and a polycarbonate polyol monomer. As the corrosion resistant hardener, Ti organic oxide (trade name Tyzor TE® titanium (IV) (triethanol aminato) isopropoxide) was used. Junsasei aluminum dihydrogen phosphate was used as a phosphate compound. Zirmel 1000 potassium zirconium carbonate from MEL Chemicals was used as a water repellent.

In this case, the soft urethane resin, the hard urethane resin, and the water repellent were adjusted as described in Table 1, and 10 parts by weight and 5 parts by weight of Ti organic oxide and aluminum dihydrogen phosphate were used, respectively.

Furthermore, 10 parts by weight of colloidal silica (Snowtex-40 from Nissan Chemical, Inc.), 0.5 parts by weight of siloxane-based wetting agent (EFKA 3580, EFKA), and a silane-based crosslinking agent (Aldrich, 3-glycidoxypropyl) 1.2 parts by weight of trimethoxysilane), 2.5 parts by weight of an amine curing agent (Cytec Cymel 303) and 1.5 parts by weight of polyethylene lubricant (Lanco PE 1500 from Novellon) were added in bulk.

The solvent was added so that the solid concentration in the surface treatment composition was 15% by weight. Water and alcohols were used as the solvent, about 3% by weight of ethanol and about 0.5% by weight of an amine compound were added as an alkaline aqueous solution, and the balance was water.

1-2. Manufacture of Coated Steel Sheet

1) Specimen: An electro galvanized steel sheet (EG) having an adhesion amount of 20 g / m 2 on one side was used as a material steel sheet for applying the surface treatment composition.

2) Coating method: The resin solution was coated on top of the sample using a continuous roll coating simulator and dried at 180 ° C under PMT conditions. The deposition amount of the film was 1,000 mg / m 2.

1-3. Property evaluation method

(1) Machinability: After measuring the friction coefficient using a drawbead friction tester (load 1,000kgf, speed 1,000mm / min, distance 100mm), the resin film of the specimen was scratched on the bead surface of the friction tester and damaged. The evaluation was made according to the following criteria.

○: less than 5% damage area

△: damage area of 5% or more but less than 10%

×: damage area 10% or more

(2) Corrosion resistance: The specimens were subjected to a salt spray test according to JIS-Z2371 for 96 hours, and the degree of corrosion was evaluated according to the following criteria.

○: less than 5% of white blue

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

×: 20% of white blue

(3) Conductivity: The surface of the specimen coated with resin coating was measured by a surface resistance meter (Loresta-GP), and evaluated according to the following criteria.

○: surface resistance less than 1mΩ

△: surface resistance of 1 mΩ or more and less than 1 Ω

×: extremely poor conductivity or weldability with a surface resistance of more than 1 Ω

(4) Alkali resistance: After dipping in water at 50 ° C alkaline solution (Gardoclean 4292L, pH12) for 5 minutes and washing with water, the color difference and peeling degree of the resin coating layer were visually observed and evaluated according to the following criteria.

○: no peeling, color difference change less than 2.0

△: no peeling, color difference change 2.0 or more occurs

X: peeling occurrence

(5) Water deterioration resistance: After immersion in water for 30 minutes, the color difference was measured after reciprocating friction 30 times with fingers, and evaluated according to the following criteria.

○: color difference less than 1.0

△: color difference 1.0 or more

X: peeling occurrence

(6) Solution stability: After 10 days of 100g of the surface treatment composition in an oven at 50 ℃, the degree of precipitation, gelation and separation of the solution was evaluated according to the following criteria.

○: no precipitation, gelation or separation

△: One of fine precipitation, gelation and separation

×: at least one of precipitation, gelation, and separation occurs to some extent

(7) High temperature and high humidity: The test piece was left to stand at 60 degreeC and 95% (R.H.) Conditions for 72 hours, and the color difference before and after that was measured and evaluated by the following reference | standard.

○: color difference less than 1.0

(Triangle | delta): Color difference 1.0 or more and less than 3.0

×: color difference exceed 3.0

The evaluation results for the above physical properties are shown in Table 1 below. Furthermore, the surfaces of the resin coated steel sheets obtained from Example 4 and Comparative Examples 1, 10 and 11 are shown in FIG. It can be seen from FIG. 2 that the degree of surface damage of Example 4 is the best when the degree of surface damage after evaluation by the drawbead friction tester is compared. 3 shows the surface state of the steel sheet after the resin coated steel sheets coated with the resin compositions of Example 5 and Comparative Example 5 were immersed in an alkaline solution. When the degree of surface appearance after evaluating the alkali resistance property by the degreasing solution was compared, it can be confirmed from FIG. 3 that the surface appearance of Example 5 according to the present invention is excellent.

Solid content (parts by weight) Quality characteristic Urethane Resin
(Soft / hard mix ratio) Water repellent Machinability Corrosion resistance conductivity Alkali resistance Domestic consumption
Deterioration solution
stability High temperature and high humidity Example One 68.8 (90/10) 0.5 ○ ○ ○ ○ ○ ○ ○ 2 63.3 (10/90) 6 ○ ○ ○ ○ ○ ○ ○ 3 59.3 (30/70) 10 ○ ○ ○ ○ ○ ○ ○ 4 49.3 (30/70) 20 ○ ○ ○ ○ ○ ○ ○ 5 68.8 (50/50) 0.5 ○ ○ ○ ○ ○ ○ ○ 6 68.3 (40/60) One ○ ○ ○ ○ ○ ○ ○ 7 61.3 (5/95) 8 ○ ○ ○ ○ ○ ○ ○ 8 57.3 (80/20) 12 ○ ○ ○ ○ ○ ○ ○ 9 53.3 (10/90) 16 ○ ○ ○ ○ ○ ○ ○ 10 61.3 (10/90) 8 ○ ○ ○ ○ ○ ○ ○ 11 49.3 (50/50) 20 ○ ○ ○ ○ ○ ○ ○ 12 59.3 (40/60) 10 ○ ○ ○ ○ ○ ○ ○ 13 65.3 (40/60) 4 ○ ○ ○ ○ ○ ○ ○ Comparative example One 69.3 (90/10) 0 × × ○ △ × ○ × 2 59.3 (100/0) 10 △ ○ ○ ○ × ○ ○ 3 59.3 (3/97) 10 △ ○ ○ ○ × ○ ○ 4 69.3 (50/50) 0 △ ○ × △ △ ○ × 5 34.3 (50/50) 35 △ ○ △ × × × ○ 6 69.0 (80/20) 0.3 ○ ○ △ ○ ○ ○ × 7 Acrylic resin 59.3 10 △ △ ○ △ ○ △ ○ 8 Silane Resin 59.3 10 ○ × △ ○ ○ ○ △ 9 Polyester resin 59.3 10 △ △ ○ ○ ○ × ○ 10 Nitrocellulose Resin 59.3 10 × △ × △ ○ × ○ 11 Epoxy Resin 59.3 10 △ ○ ○ △ ○ ○ ○

As can be seen from the table, the steel sheet coated using the resin composition according to the present invention was excellent in workability, corrosion resistance, conductivity, alkali resistance and solution stability, as well as excellent in water deterioration resistance and high temperature and high humidity. Compared with the composition of about 5 to 15% had an effect of improving high temperature and high humidity.

On the other hand, in the case of using a resin composition outside the scope of the present invention, when no water repellent is used, or when the amount of water repellent is insufficient (Comparative Examples 1, 4 and 6), as well as workability, corrosion resistance, etc., heat resistance and high temperature and high humidity resistance Poor and excessive water repellent content (Comparative Example 5) showed poor heat resistance, alkali resistance as well as solution stability. Furthermore, when the mixed urethane resin of the present invention is not used or the mixing ratio is outside the scope of the present invention (Comparative Examples 2, 3, 7 to 11), it is not good in various physical properties such as heat resistance and workability.

[ Example  14-19 and Comparative example  12-14]

2-1. Manufacture of Coated Steel Sheet

1) Specimen: An electro galvanized steel sheet (EG) having an adhesion amount of 20 g / m 2 on one side was used as a material steel sheet for applying the surface treatment composition.

2) Coating method: A resin composition having the composition of Example 4 was prepared, and the resin composition was applied to the upper portion of the steel sheet using a continuous roll coating simulator, and dried under the adhesion amount and PMT conditions as shown in Table 2.

2-3. Performance Evaluation Method

The workability, conductivity and corrosion resistance of the specimen prepared under the above conditions were evaluated by applying the evaluation method shown in [Table 1].

2-4. Evaluation results

Table 2 shows the performance of the metal surface treatment composition under the above conditions.

Resin treatment condition Quality characteristic Amount of Attachment (mg / ㎡) PMT (℃) Machinability conductivity Corrosion resistance Example 14 1,000 180 ○ ○ ○ Example 15 500 180 ○ ○ ○ Example 16 800 180 ○ ○ ○ Example 17 1,500 180 ○ ○ ○ Example 18 1,000 120 ○ ○ ○ Example 19 1,200 150 ○ ○ ○ Comparative Example 12 200 180 × ○ × Comparative Example 13 2,000 180 ○ × ○ Comparative Example 14 1,000 110 × ○ ×

As can be seen from Table 2, the resin coated steel sheet coated with the resin adhesion amount of the present invention was excellent in both workability, conductivity and corrosion resistance, but when the adhesion amount is a small amount out of the scope of the present invention (Comparative Example 12) And the corrosion resistance is insufficient, it can be seen that the conductivity is insufficient in the case of excess (Comparative Example 13). In addition, when dried under PMT conditions of 110 ° C. (Comparative Example 14), it was found that workability and corrosion resistance were insufficient.

1 is a schematic structural diagram of a steel sheet manufactured by applying a resin coating layer as an example of the present invention.

Figure 2 compares the degree of surface damage after evaluating the processing characteristics of one embodiment of the present invention and the existing invention material with a draw bead friction tester.

Figure 3 compares the degree of surface appearance after evaluating the alkali resistance characteristics of one embodiment of the present invention and the existing invention with a degreasing solution.

Claims (14)

Mixed urethane resins of the soft urethane resin and the hard urethane resin; Ti or Zr-based organic oxides; At least one compound selected from the group consisting of monoaluminum phosphate, aluminum dihydrogen phosphate, first zinc phosphate and hydrated manganese phosphate; Water repellents selected from potassium zirconium carbonate, ammonium zirconyl carbonate and mixtures thereof; And a solvent. The resin composition for surface treatment of a steel sheet. The method of claim 1, wherein the resin composition, 10 to 90 parts by weight of a mixed urethane resin; 1 to 20 parts by weight of Ti or Zr-based organic oxide; 0.1 to 10 parts by weight of a compound selected from the group consisting of monoaluminum phosphate, aluminum dihydrogen phosphate, first zinc phosphate, and hydrated manganese phosphate; And 0.5 to 20 parts by weight of a water repellent. The resin composition for surface treatment of a steel sheet according to claim 1, wherein the mixed urethane resin is composed of 5 to 95% by weight of a soft urethane resin and 5 to 95% by weight of a hard urethane resin. The method of claim 1, wherein the soft urethane-based resin is prepared from isophorene diisocyanate, adipic acid and polyhydric alcohol or from acrylic polyol and polyisocyanate, characterized in that the polyurethane having a number average molecular weight of 5,000 to 300,000. Resin composition for surface treatment of a steel plate. The resin composition for surface treatment of a steel sheet according to claim 4, wherein the polyhydric alcohol is selected from acryl polyol, polyester polyol, polyether polyol, polyolefin polyol or a mixture thereof. The method of claim 1, wherein the rigid urethane-based resin is a polyurethane resin prepared from polycaprolactone polyol or polycarbonate polyol and diisocyanate, 4,4'-bis (ω-hydroxyalkyleneoxy) biphenyl and methyl-2 A resin composition for surface treatment of a steel sheet, which is selected from a polyurethane resin prepared from 6-diisocyanate hexanoate and a polyurethane resin having an acetal bond, wherein the number average molecular weight is 200,000 to 2,000,000. The resin composition for surface treatment of a steel sheet according to claim 6, wherein the hard urethane resin has Shore A hardness of 40 to 90. The resin composition for surface treatment of a steel sheet according to claim 6, wherein the diisocyanate is paraphenylene diisocyanate. The method of claim 1, wherein the Ti or Zr organic oxide is titanium diisopropoxide bis (acetylacetonate), titanium ortho ester, titanium (IV) butoxide, titanium (IV) (triethanol aminato) isopropoxide Seeds, tetrakis (triethanolaminato) zirconium (IV), titanium (IV) 2-ethylhexoxide, titanium (IV) isopropoxide, zirconium (IV) bis (diethyl citrato) -dipropoxide or A resin composition for surface treatment of a steel sheet, characterized in that it is selected from a mixture of these. The resin composition for surface treatment of a steel sheet according to claim 1, wherein the solvent comprises a solid content of the resin composition in an amount of 5 to 25% by weight. The resin composition for surface treatment of a steel sheet according to claim 10, wherein the solvent is water. 12. The alkaline aqueous solution according to claim 11, wherein the solvent is an alcohol solvent selected from ethanol, methanol, propanol, isopropanol and glycerol, an amine compound, N-methylpyrrolidone, sodium hydroxide, potassium hydroxide, sodium carbonate and ammonium hydroxide. Or a resin composition for surface treatment of a steel sheet, further comprising a mixture thereof. The method of manufacturing a surface-treated steel sheet comprising the step of coating the resin composition of any one of claims 1 to 12 on the upper steel sheet and then coated with an adhesion amount of 300 to 1,800 mg / ㎡, and drying at a temperature of 120 ~ 200 ℃ PMT. . A plated or unplated steel sheet includes a resin coating layer, The resin coating layer is a surface-treated steel sheet, characterized in that the coating of the resin composition of any one of claims 1 to 12 after coating on the upper steel sheet with an adhesion amount of 300 to 1800 mg / ㎡.

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