KR101568156B1 - High corrosion-resistance laminated color steel sheet and manufacturing method thereof - Google Patents

Abstract

An embodiment of the present invention provides a highly corrosion resistant laminate colored steel sheet comprising a base steel sheet, a pretreatment layer, an undercoat layer, a top coat layer made of a thermoplastic polyolefin coating composition, and a thermoplastic polyolefin film, and a method of manufacturing the same do.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a high corrosion resistant laminate colored steel sheet,

The present invention relates to a highly corrosion resistant laminate colored steel sheet and a method of manufacturing the same. More particularly, the present invention relates to a highly corrosion resistant laminate colored steel sheet comprising a steel sheet coated with a thermoplastic polyolefin film by using a thermoplastic polyolefin coating composition and a method for producing the same.

The colored steel sheet is used for various purposes such as being used as interior and exterior materials for cases of household appliances and various buildings, and the use of such color steel plates is required not only for corrosion resistance and durability but also for high productivity and excellent aesthetics. Research and development is actively being carried out.

Particularly, in the case of the steel sheet roof material, there is a problem of leakage of the bolt portion connecting the steel sheet and the steel sheet due to changes in the external environment. In addition, since the replacement period of the roofing material is about 15 years or more, the corrosion resistance and durability of the steel sheet are required, and weather resistance, water resistance, cold resistance, heat resistance and flame resistance are also required.

In this regard, conventionally, a laminated steel sheet in which a thermoplastic polyolefin film is laminated using an adhesive (epoxy type, urethane type, hot melt type) on a plated steel sheet has been applied. In this case, Which is one of the problems in corrosion resistance has occurred.

Therefore, the demand for high-corrosion-resistant color steel plates is continuously increasing, and research and development of the corresponding products is required.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art described above, and it is an object of the present invention to provide a thermoplastic polyolefin laminate colored steel sheet capable of preventing leakage phenomenon in a bolt portion connecting a steel sheet to a steel sheet, And to provide a manufacturing method thereof.

In order to accomplish the above object, an embodiment of the present invention provides a laminate color steel sheet comprising a base steel sheet, a pretreatment layer, a bottom coat layer, a top coat layer made of a thermoplastic polyolefin coating composition, and a thermoplastic polyolefin film sequentially Resistant laminate colored steel sheet.

In one embodiment, the pretreatment layer may be a phosphate coating, a chromate or a non-chromate coating.

In one embodiment, the undercoating layer may be at least one selected from the group consisting of polyester-based, epoxy-based, urethane-based, and acrylic-based paints.

In one embodiment, the thermoplastic polyolefin-based coating composition may include a modified polyolefin and a solvent.

In one embodiment, the solvent may be at least one selected from the group consisting of esters, alcohols, ketones, aliphatic hydrocarbons, and aromatic hydrocarbons.

In one embodiment, the content of the modified polyolefin may be 10% by weight to 50% by weight based on the total weight of the thermoplastic polyolefin-based coating composition.

According to another aspect of the present invention, there is provided a method of manufacturing a laminate color steel sheet, comprising the steps of: (a) applying a phosphoric acid film on a base steel sheet, a chromate or non-chromate- Forming a pretreated layer; (b) applying a solvent-type coating composition on the pretreatment layer to form an undercoat layer; (c) applying a thermoplastic polyolefin-based coating composition on the undercoat layer to form an overcoat layer; And (d) laminating a thermoplastic polyolefin film on the top coat layer. The present invention also provides a method for producing a highly corrosion resistant laminate colored steel sheet.

In one embodiment, the solvent-type coating composition may be at least one selected from the group consisting of polyester-based, epoxy-based, urethane-based, and acrylic-based coatings.

In one embodiment, the thermoplastic polyolefin-based coating composition may include a modified polyolefin and a solvent.

In one embodiment, the solvent may be at least one selected from the group consisting of esters, ethers, alcohols, ketones, aliphatic hydrocarbons, and aromatic hydrocarbons.

In one embodiment, the content of the modified polyolefin may be 10% by weight to 50% by weight based on the total weight of the thermoplastic polyolefin-based coating composition.

According to one embodiment of the present invention, the upper coat layer made of the thermoplastic polyolefin coating composition can be used as an adhesive layer to enhance the adhesion to the undercoat and improve the corrosion resistance of the colored steel sheet. In addition, according to one embodiment of the present invention, a phosphoric acid coating layer, a chromate or non-chromate coating layer may be formed on the base steel sheet to further improve the adhesion between the base steel sheet and the coating layer.

It should be understood that the effects of the present invention are not limited to the above effects and include all effects that can be deduced from the detailed description of the present invention or the composition of the invention described in the claims.

1 is a cross-sectional view of a highly corrosion resistant laminate color steel sheet according to an embodiment of the present invention.
2 is a cross-sectional view of a highly corrosion resistant laminate color steel sheet according to another embodiment of the present invention.
3 is a schematic view illustrating a method of manufacturing a highly corrosion resistant laminated steel sheet according to an embodiment of the present invention.
4 is a schematic view illustrating a method of manufacturing a highly corrosion resistant laminated steel sheet according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "indirectly connected" . Also, when an element is referred to as "comprising ", it means that it can include other elements, not excluding other elements unless specifically stated otherwise.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

High corrosion resistance laminate color steel plate

1 is a cross-sectional view of a highly corrosion resistant laminate color steel sheet according to an embodiment of the present invention.

1, a highly corrosion resistant laminate colored steel sheet 100 according to an embodiment of the present invention includes a base steel sheet 110, a pretreatment layer 120, a undercoating layer 130, and a top coat made of a thermoplastic polyolefin coating composition A coating layer 140, and a thermoplastic polyolefin film 150 sequentially.

As used herein, the term "sequential" means that the steel plate is sequentially processed in order and refers to the order from bottom to top with respect to the base steel sheet.

The shape of the cross section of the substrate steel sheet 110 is not limited, and embossed or patterned embossed patterns may be used. The embossed pattern may be formed by forming a coating layer and then processing it in a final step. Specifically, the surface of the base steel sheet 110 may be a smooth surface, or may be a non-planar surface including a protrusion.

The base steel sheet 110 is a hot-dip galvanized steel sheet used in a normal continuous coating process, and may be a general hot-dip galvanized steel sheet, Galvannealed Sheet Steel (GA), Galfan, or Zinc Aluminum Alloy Coated Steel Sheets and Galvalume) and preferably 50 to 55% of an aluminum coated steel plate (super galvalume steel plate) or a galvanized steel plate (GI), chromium (Cr), aluminum (Al) ), Copper (Cu), and the like, but is not limited thereto.

As used herein, the term "hot-dip galvanized steel sheet" refers not only to pure zinc plating but also to hot-dip galvanized steel sheets such as Galvannealed Steel Sheets (GA) Steel plates may also be included.

Specifically, a general hot-dip galvanized steel sheet is obtained by immersing a cold-rolled steel sheet or a hot-rolled steel sheet in a hot dip galvanizing bath and coating the surface with a zinc coating, whereby the zinc plated layer is thick and exhibits excellent corrosion resistance.

Galvanized sheet steel (GA) is reheated at a high temperature of about 500 ° C after hot dip galvanizing, and iron (Fe) is diffused into the plating layer to form an iron-zinc alloy layer having an iron concentration of about 10% Which is excellent in corrosion resistance and adhesion to paint.

Galfan is a zinc-aluminum alloy coated steel sheet. The Zn + 5% A system has a corrosion resistance about 2 to 3 times higher than that of a hot-dip galvanized steel sheet and can exhibit excellent corrosion resistance after coating. In order to improve plating wettability, mischmetal of lanthanum (La) or cerium (Ce) is added and magnesium (Mg) may be added to prevent deterioration of plating adhesion due to intergranular corrosion have. More specifically, it is possible to use an alloy-coated steel sheet of Zn + 55% Al + 1.6% Si, Zn + 4.5-5% Al + 0.1% Mischmetal or 0.2% Mg plated steel sheet, , 1% Al, or the like may be used.

The pretreatment layer 120 according to an embodiment of the present invention may be a chemical conversion coating such as a phosphate coating, a chromate, a non-chromate, or the like.

As used herein, the term " chemical conversion coating "refers to a poorly soluble corrosion product layer formed on a metal surface by a chemical or electrochemical reaction by bringing the clean surface of the above-ground steel sheet into contact with a corrosion solution prepared under specific conditions. Examples of the corrosion products include, but are not limited to, oxides, phosphates, and chromates.

The pretreatment layer 120 removes foreign matter adhered to the surface of the backing steel sheet 110 to enhance the adhesion between the backing steel sheet 110 and the backing coat layer 130 and the corrosion resistance of the backing steel sheet 110 And may be formed by washing the base steel sheet 110 with an alkaline degreasing agent and then chromating it with a coating thereon, or by non-chromate treatment during manufacture for home use.

As used herein, the term " chromate treatment "means that a steel sheet is immersed in a solution containing chromic acid or a dichromate salt as a main component to coat a rust preventive coating.

On the other hand, an environmentally friendly non-chromate film treatment can be carried out for good film adhesion. However, since the corrosion resistance may be lowered compared with the conventional chromate film treatment, it is preferable to use a known chromate or trivalent chromium Cr ^< ^{3 + &} gt ^; ) can be carried out.

The undercoat layer 130 according to an embodiment of the present invention may be formed of at least one selected from the group consisting of polyester, epoxy, urethane, and acrylic paint.

The undercoating layer 130 is for enhancing the durability of the color steel sheet and for enhancing the interlaminar adhesion between the pre-treated base steel sheets 120 and 110 and the upper overcoat layer 140, Examples of ester-based paints include YP500 series of Koryo Chemical, 8600 series of construction chemicals, Fine coat P-331 of Samhwa paint, and K004 series of Sigma Samsung coating. However, the present invention is not limited thereto.

The undercoating layer 130 not only strengthens the corrosion resistance and interlayer adhesion of the colored steel sheet but also provides an elongation ratio so as to serve as a buffer at the interface between the pretreatment layer 120 and the top coat layer 140, So that it is possible to prevent the impact from being transmitted to the upper coating layer 140.

The pigment used for the undercoat layer 130 may be selected from a group of rust-preventive pigments for high corrosion resistance of the product, organic and inorganic pigments used for the PCM paint, similar to the top coat layer 140 Can be used.

As used herein, the term "anti-corrosive pigment" refers to a pigment that reacts with the oil in the vehicle to form a metallic soap in a coating film for preventing rust-preventive rust, or is decomposed by water to become alkali- Pigments that exhibit a rust-inhibiting effect, such as making or increasing aeration resistance.

Examples of the anticorrosive pigment include red lead containing lead and chromium, zinc carbonate, zinc tetraoxy chromate and strontium chromate. But is not limited thereto.

The dry film thickness of the undercoat layer 130 may be 2 to 10 탆, preferably 4 to 6 탆. If the thickness of the dried coating film is less than 2 탆, the rust prevention property and the interlayer bonding force may be deteriorated. If the thickness is more than 10 탆, economical efficiency and surface appearance disadvantage may occur.

The top coat layer 140 according to an embodiment of the present invention may be formed of a thermoplastic polyolefin coating composition, and the thermoplastic polyolefin coating composition may include a modified polyolefin and a solvent.

The top coat layer 140 formed by coating the thermoplastic polyolefin coating composition can compensate for the disadvantages of thermosetting and thermoplastic coatings such as epoxy, urethane, and hot melt adhesives commonly used in the art, such as adhesiveness to undercoats and corrosion resistance .

However, the thermoplastic polyolefin coating composition is difficult to coat or adhere because it is non-polar and crystalline, unlike a polar substrate such as a polyurethane resin, a polyamide resin, an acrylic resin, and a polyester resin. Therefore, it is preferable to use a modified polyolefin-based coating composition.

Examples of the modified polyolefin coating composition include an acid-modified polyolefin resin containing an unsaturated carboxylic acid modification, a propylene-based random copolymer using an amorphous polyolefin resin as a raw material (in the production of polypropylene, , A modified polyolefin resin obtained by reacting an unsaturated carboxylic acid including maleic anhydride graft-modified with a polyolefin resin with a polyester or an alcohol, a polyolefin resin modified with an unsaturated carboxylic acid and an acrylic derivative by an amorphous polyolefin resin . In addition to the above, the modified polyolefin coating composition may further contain a resin such as a urethane resin, an epoxy resin, an acrylic resin, a phenol resin, an alkyd resin, a polyamide resin, a polyimide resin, a silicone resin, a nitrile (Nitrocellulose) But the present invention is not limited thereto.

Preferably, the acid-modified polyolefin resin containing the unsaturated carboxylic acid modification may be used. As the unsaturated carboxylic acid or acid anhydride, one or more polymerizable double bonds in one molecule may be used, and the number of carbon atoms not containing 3 (Meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, maleic anhydride, and the like can be given as non-limiting examples of the aliphatic carboxylic acid or its anhydride.

The unsaturated carboxylic acid or acid anhydride modified polyolefin may be further subjected to acrylic modification if necessary. Examples of the acrylic unsaturated monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl C1-C21 alkyl esters of (meth) acrylic acid such as ethylhexyl, lauryl (meth) acrylate and stearyl (meth) acrylate; C1-C21 hydroxyalkyl esters of (meth) acrylic acid such as 2-hydroxyethyl (meth) acrylate and 3-hydroxypropyl (meth) acrylate; (Meth) acrylic acid, glycidyl (meth) acrylate, (meth) acrylamide, (meth) acrylonitrile and other acrylic monomers. These may be used alone or in combination of two or more.

On the other hand, the solvent may be at least one selected from the group consisting of esters, alcohols, ketones, aliphatic hydrocarbons, aliphatic hydrocarbons, and aromatic hydrocarbons.

Examples of the ester-based solvent include methyl acetate, ethyl acetate, n-butyl acetate, cellosolve acetate, propylene glycol monomethyl acetate, 3-methoxybutyl acetate, methyl butylate, ethyl butylate and propyl propionate However, the present invention is not limited thereto.

Examples of the alcohol-based solvent include methanol, ethanol, propanol, isopropanol, n-butanol, amyl alcohol, octyl alcohol and decanol.

Examples of the ketone-based solvent include, but are not limited to, acetone, cyclohexanone, methyl amyl ketone, diisobutyl ketone, methyl ethyl ketone, methyl isobutyl ketone and the like.

Examples of the aliphatic hydrocarbon-based solvent include chain-like hydrocarbons such as pentane, hexane, heptane, octane, nonane, decane, dodecane, tetradecane, hexadecane and the like, and alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, ethylcyclohexane, cyclohexanol and the like Cyclic hydrocarbons, but are not limited thereto.

Examples of the aromatic hydrocarbon-based solvent include, but are not limited to, benzene, ethylbenzene, chlorobenzene, toluene, xylene, and the like.

Preferably, a mixture of a cyclohexane-based aliphatic solvent and an ester-based or ketone-based solvent may be used from the viewpoint of environmental problems.

According to an embodiment of the present invention, the content of the modified polyolefin may be 10% by weight to 50% by weight based on the total weight of the thermoplastic polyolefin-based coating. If the content of the modified polyolefin is less than 10% by weight, not only the adhesive strength is lowered but also the viscosity is lowered to make it difficult to realize a smooth surface. If the modified polyolefin content is more than 50% by weight, economical efficiency may be lowered and the coating layer may be thickened.

On the other hand, the thermoplastic polyolefin-based coating composition may further contain an inorganic material or rubber.

The inorganic material may be at least one selected from the group consisting of calcium carbonate, talc, mica, and zeolite for shortening the cooling rate of the thermoplastic polyolefin coating composition and improving the bending strength and hiding power.

In addition, the thermoplastic polyolefin-based coating composition may further contain ethylene-vinyl acetate (EVA), ethylene propylene diene monomer (EPDM), styrene-butadiene rubber a rubber component selected from the group consisting of styrene-butadiene rubber (SBR), and nitrile-butadiene (NBR).

The content of the inorganic or rubber component may be 0.5% by weight to 30% by weight based on the total weight of the thermoplastic polyolefin-based coating composition. If the content of the inorganic or rubber component exceeds 30% by weight, the workability and flexibility may be lowered or the impact strength may be weakened.

Examples of the polyolefin resin used for the thermoplastic polyolefin film 150 include polyethylene (PE), polypropylene (PP), polyisobutylene (PIB), and polyvinyl alcohol (PVA) May be included as polymerized units. Further, the polyolefin resin may include a copolymer, a graft, a modified resin, and a self-crosslinked resin. Examples of the water-soluble polyolefin resin include an unsaturated carboxylic acid or an acid anhydride-modified polyolefin. Such a modified polyolefin can be usually obtained by graft-polymerizing an unsaturated carboxylic acid or an acid anhydride to a polyolefin by a known method, and if necessary, a catalyst may be used.

The number average molecular weight of the polyolefin resin may be 500,000 to 2,000,000. If the molecular weight of the olefin-based resin is less than 500,000, the crosslinking density is increased and the workability may be deteriorated. If the olefin-based resin is more than 2,000,000, the water-solubility is difficult and the resin may settle and the corrosion resistance may be deteriorated.

2 is a cross-sectional view of a highly corrosion resistant laminate color steel sheet according to another embodiment of the present invention.

2, a highly corrosion-resistant laminated steel sheet 100 according to an embodiment of the present invention may be formed of a polyester-based, epoxy-based, urethane-based or polyurethane-based material between the undercoat layer 130 and the upper coat layer 140 And an acrylic paint. The intermediate coating layer 160 may be formed of at least one selected from the group consisting of acrylic paints.

The intermediate coating layer 160 can enhance the durability of the steel sheet and enhance the interlaminar adhesion between the upper coating layer 140 and the lower coating layer 130. The intermediate coating layer 160 serves to buffer the interface between the lower coating layer 130 and the upper coating layer 140 by applying an elongation to absorb the impact generated during the processing of the laminated color steel sheet It is possible to prevent the impact from being transmitted to the top coat layer 140. The anti-corrosive pigment used for the intermediate coat layer 160 may be the same as that used for the undercoat layer 130, and the kind and function of the anti-corrosive pigment are as described above.

METHOD FOR MANUFACTURING HIGH RESISTANCE LAMINATED COLORED STEEL SHEET

3 is a schematic view illustrating a method of manufacturing a highly corrosion resistant laminated steel sheet according to an embodiment of the present invention.

Referring to FIG. 3, a method of manufacturing a highly corrosion resistant laminate color steel sheet according to an embodiment of the present invention includes the steps of (a) forming a pretreatment layer on a base steel sheet by phosphoric acid coating, chromate, or non- (S110); (b) applying a solvent-type coating composition on the pretreatment layer to form an undercoat layer (S120); (c) forming a top coat layer by applying a thermoplastic polyolefin-based coating composition on the undercoat layer (S130); And (d) laminating the thermoplastic polyolefin film on the top coat layer (S140).

In step S110 of preparing the base steel sheet, the types and characteristics of the base steel sheet are the same as those described above.

The step (S110) of forming a pretreatment layer having a chemical conversion coating with a phosphoric acid coating, a chromate or a non-chromate on the backing steel sheet may include a step of cleaning the backing steel sheet with an alkaline degreasing agent, followed by degreasing, Followed by a film treatment with non-chromate, followed by drying and air-cooling or water-cooling. The types and characteristics of the above-described base steel sheets are as described above.

The cleaning may be performed using an alkali or acidic degreasing agent, hot water, or a solvent to remove foreign matter adhering to the backing steel sheet in the pre-coating step. Thereafter, the surface may be adjusted with an acid, an alkali or the like, if necessary. Further, in the cleaning step of the surface of the base steel sheet, it is preferable to wash the base sheet after washing so that the cleaning agent does not remain on the surface of the base steel sheet.

As the phosphate solution for the phosphoric acid coating treatment, a zinc phosphate, a manganese phosphate or an iron phosphate can be introduced, preferably a phosphorus zinc phosphate can be introduced. The zinc phosphate may contain nickel, manganese , And calcium may be added.

As the chromate treatment solution, a solution containing chromic acid or a dichromate salt as a main component may be used. However, in the chromate treatment, hexavalent chromium (Cr ^{6 +} ) is generated as wastewater, , And trivalent chromium (Cr ^{3 +} ), which is less toxic, can be used.

The solution for the non-chromate treatment includes 9 to 13 wt% of an epoxy silane coupling agent, 5 to 9 wt% of an amino silane coupling agent, 0.5 to 1 wt% of a vanadium compound, 0.5 to 1 wt% of phosphoric acid, A solution containing 0.5 to 1 wt% of Ti-alkoxide, 0.1 to 10 wt% of a chelate, 0.1 to 2 wt% of a chelating agent, 0.1 to 5 wt% of a calcium phosphate-based compound, 0.2 to 10 wt% of colloidal silica, But is not limited thereto.

Thereafter, the surface treatment solution such as the phosphate solution, the chromate treatment solution, and the non-chromate treatment solution is applied to the surface of the base steel sheet. The application method includes a roll coating method in which the coating solution is roll-transferred onto the surface of the base steel sheet, a method of squeezing the treatment agent from the roll after spraying by spraying or the like, a method of immersing the base steel sheet in a bath containing the surface treatment solution Method, and the like may be used, but the present invention is not limited thereto.

Thereafter, the surface treatment solution is dried at 50 to 100 ° C for 0.1 to 60 seconds, and then heated to 30 to 200 ° C. At this time, if the heating temperature (PMT) is less than 30 DEG C, a problem of corrosion resistance may occur. If the heating temperature is more than 200 DEG C, the productivity may be deteriorated.

The step S120 of applying a solvent type coating composition on the pretreatment layer to form a primer coating layer may be performed by coating a primer coating on the primer layer, But not limited to, a curtain flow method as well as a curtaining method.

Drying conditions after coating are PMT (Peak Metal Temperature) of 120 ~ 200 ℃ in continuous line. If the PMT is less than 120 ° C, the corrosion resistance may be weakened. If the PMT is more than 200 ° C, the productivity may be deteriorated.

The undercoating layer according to an embodiment of the present invention may be formed using at least one solvent-type coating composition selected from the group consisting of polyester-based, epoxy-based, urethane-based, and acrylic-based coatings, The kind, composition, and composition ratio of the polymer are the same as those described above. The dry film thickness of the undercoat layer is also the same as described above.

As the pigment used for the undercoat layer 130, a part of the anticorrosive pigment may be used for corrosion resistance, and the organic or inorganic pigment used for the PCM paint may be selected and used according to the application.

In step S130 of applying a thermoplastic polyolefin coating composition on the undercoat layer according to an embodiment of the present invention to form an overcoat layer, a modified polyolefin coating composition of the same kind as the above- Or the like.

The modified polyolefin coating composition is applied onto the undercoating layer and then the plate including the base steel sheet, the pretreatment layer and the undercoating layer is passed through an oven at a temperature of 150 to 250 ° C to form the modified polyolefin coating composition And the plate can be preheated to 100 DEG C or higher. If the heating temperature is lower than 150 ° C, the adhesion between the thermoplastic polyolefin film 150 and the upper coat layer may be weakened. If the heating temperature is higher than 250 ° C, equipment such as a drying furnace for heating and drying at a high temperature is required. The energy consumption may be excessive and the productivity may be lowered, and the adhesion between the thermoplastic polyolefin film and the top coat layer may also be deteriorated.

The step (S140) of laminating the thermoplastic polyolefin film on the top coat layer comprises laminating the sheet and the thermoplastic polyolefin film sequentially comprising the base steel sheet, the pre-treatment layer, the undercoat layer, and the top coat layer, And a continuous pressing process in which at least one squeeze roll for squeezing is passed between the upper roll and the lower roll.

Finally, the colored steel sheet laminated with the thermoplastic polyolefin film is cooled with cooling water at room temperature and cooling air to complete a laminate color steel sheet.

4 is a schematic view illustrating a method of manufacturing a highly corrosion resistant laminated steel sheet according to another embodiment of the present invention.

Referring to FIG. 4, the method of manufacturing the highly corrosion-resistant laminated steel sheet according to the present invention includes the steps of (b) applying a solvent type coating composition on the pretreatment layer to form an undercoat layer (S120) , Urethane-based coatings, and acrylic-based coatings to form an intermediate coating layer (S150).

The step of forming the intermediate coating layer (S150) may be performed by coating the intermediate coating on the lower coating layer, and the coating method of forming the lower coating layer (S120) may be applied in the same manner . Thereafter, the intermediate coated layer can be formed by passing the plate coated with the intermediate coating through an oven disposed on a continuous line, drying or baking and cooling again. The function, properties, and composition of the intermediate coating layer, including the anti-corrosive pigment, are as described above.

Further, each step of the method for manufacturing a highly corrosion-resistant laminated steel sheet according to an embodiment of the present invention is preferably a continuous process.

In the case of a discontinuous process such as a conventional sheet method, a plate-like base steel sheet having a predetermined size is arranged in a coating process line using a conveyor system, and the plate-like base steel sheet is coated and dried Whereby a colored steel sheet in the form of a sheet can be produced. However, in the discontinuous process, the productivity is decreased in proportion to the interval between the sheets, and the sheet-type color steel sheet produced by the discontinuous process has a problem of low storage efficiency at the time of product storage and low transportation efficiency at the time of product shipment .

On the other hand, in the case of the continuous process, the continuous steel sheet which is not separated and separated continuously so as to have a certain size passes through each process step of the continuous line, and the finished product is not rolled Wound and stored. Therefore, the continuous type process is excellent in productivity compared to the conventional discontinuous type process, and can greatly improve the storage efficiency and transportation efficiency.

Hereinafter, embodiments of the present invention will be described in detail.

Examples 1 to 4 and Comparative Examples 1 and 2: Preparation of Specimens 1 to 6

Specimens are manufactured under standard conditions unless otherwise specified. Standard condition refers to the standard condition (temperature 20 ± 2 ℃, humidity 65 ± 10%) specified in KS L 0006. The same conditions are applied to the following examples and comparative examples.

A pretreatment agent was applied to GI (hot dip galvanized steel), and a coating composition including a polyester resin, a pigment, an additive, and an antirust agent was applied and dried to form a PCM primer. Then, the thermoplastic polyolefin film composition was applied, and then the thermoplastic polyolefin film was laminated to produce a laminate colored steel sheet.

18% by weight of modified polyolefin; And a residual solvent mixture of methylcyclohexane, n-butyl acetic acid, isopropyl alcohol, and xylene were mixed to prepare a thermoplastic polyolefin-based coating composition, which was applied to the top coat layer or the adhesive layer. The components of the modified polyolefin and the composition ratios of the respective components are shown in Table 1 below. Unless otherwise specified, the unit of the composition ratio shown in Table 1 below is% by weight.

division Emulsion
Acrylic resin Polyurethane Disperse Resin Polyolefin resin Number average molecular weight Example 1 (Piece 1) 20 30 50 10000 Example 2 (Piece 2) 20 30 50 25000 Example 3 (Piece 3) 20 30 50 5000 Example 4 (Piece 4) - - 100 15000 Comparative Example 1 (Specimen 5) 100 - - 10000 Comparative Example 2 (Specimen 6) - 100 - 10000

Experimental Example 1: Physical properties test for Examples 1 to 4 and Comparative Examples 1 and 2

The specimens of Examples 1 to 4 and Comparative Examples 1 and 2 were evaluated for corrosion resistance, hardness, workability and workability, and the results are shown in Table 2 below. The physical property test method used in the experimental example is as follows.

1) Corrosion resistance: The specimen was cut into 50 mm x 100 mm, and the cross-section was completely sealed with OPP tape. Then, in a salt water spraying environment of 5% by weight NaCl aqueous solution at 35 캜, the surface area was measured by ASTM- Measured time of occurrence (240 hours standard)

2) Hardness: The hardness of the coating surface is measured using a hardness tester

3) Processability: T bending at room temperature (20 ℃)

4) Workability: It is confirmed whether it is easy to form a coating film using Bar Coater of Lab

5) Chemical resistance: After immersing in NMP (N-Methyl Pyrolidone) at 60 ℃ for 3 minutes,

6) Adhesiveness: After scratching with a knife having a width of 1 mm and a length of 10 x 10 cm, the film is completely peeled off with a Scotch tape,

7) Cold resistance: The cold resistance of insulating material of cable is measured by the method specified in IEC 60811 and evaluated for fracture and cracking at -40 ° C.

The corrosion resistance, hardness, workability and workability of the coating compositions of Examples 1 to 4 and Comparative Examples 1 and 2 applied to the top coat layer of the high corrosion-resistant laminated steel sheet according to an embodiment of the present invention were evaluated. Table 2 shows the results.

division Corrosion resistance Hardness Processability Workability Example 1 (Piece 1) ◎ ◎ ◎ ◎ Example 2 (Piece 2) ◎ ○ ◎ × Example 3 (Piece 3) ○ ◎ × △ Example 4 (Piece 4) × ◎ × ○ Comparative Example 1 (Specimen 5) × △ ○ ○ Comparative Example 2 (Specimen 6) ○ △ ○ ○

(Relative Evaluation Criteria: Excellent, Good, Fair, and Poor)

Referring to Table 2, it was confirmed that the laminate color steel sheet produced according to the embodiment of the present invention has relatively better physical properties than Comparative Examples 1 and 2. Particularly, when the coating composition of Example 1 is applied to the top coat layer, it can be seen that the corrosion resistance, hardness processability and workability are both excellent. Therefore, in Experimental Example 2, the specimen of Example 1 having the best quality was used as a test piece (50 mm X 100 mm, t 0.5 mm), and the properties of the product were evaluated according to the types of the pretreatment layer and the presence or absence of the undercoat.

Example 5 and Comparative Examples 3 to 5 Preparation of Pellets 7 to 10

After the specimen of Example 1 was prepared as a test piece (50 mm X 100 mm, t 0.5 mm), it was examined whether the pretreatment layer was a non-chromate or chromate film layer and whether or not the specimen 7 to 10 . Table 3 shows the types of pretreatment layers and the presence or absence of undercoat for each of the specimens 7 to 10.

division Pretreatment layer Undercoat layer Non-chromate Chromate radish U Example 5 (Piece 7) √ √ Comparative Example 3 (Piece 8) √ √ Comparative Example 4 (Piece 9) √ √ Comparative Example 5 (Piece 10) √ √

Experimental Example  2 : Example  5 and Comparative Example  3 ~ 5 Physical properties of specimens

The corrosion resistance, chemical resistance, adhesion, workability and cold resistance of the specimens of Example 5 and Comparative Examples 3 to 5 were evaluated. Experimental methods for evaluation were the same as those of Experimental Example 1, and the results are shown in Table 4 below.

division Corrosion resistance Chemical resistance Attachment Processability Cold resistance Example 5 (Piece 7) ◎ ◎ ◎ ◎ ◎ Comparative Example 3 (Piece 8) △ △ ○ ○ ○ Comparative Example 4 (Piece 9) × △ ○ ○ ○ Comparative Example 5 (Piece 10) ○ △ ○ ○ ○

(Relative Evaluation Criteria: Excellent, Good, Fair, and Poor)

Referring to Table 4, it was confirmed that the laminate color steel sheet produced according to Example 5 exhibited higher corrosion resistance than Comparative Examples 3 to 5, and was also excellent in chemical resistance, adhesiveness, workability, and cold resistance.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

Claims (11)

In a laminate colored steel sheet,
Wherein the thermoplastic polyolefin coating composition comprises 10 to 50% by weight of a modified polyolefin, 0.5 to 50% by weight of an inorganic or a rubber, and a thermoplastic polyolefin film, wherein the thermoplastic polyolefin coating composition comprises a thermoplastic polyolefin film, an undercoat layer, a chromate coating layer, 30% by weight, and a residual amount of a solvent.
delete The high corrosion resistant laminate color steel sheet according to claim 1, wherein the undercoat layer comprises at least one selected from the group consisting of polyester-based, epoxy-based, urethane-based and acrylic-based paints.
delete The high corrosion resistant laminate color steel sheet according to claim 1, wherein the solvent is at least one selected from the group consisting of esters, ethers, alcohols, ketones, aliphatic hydrocarbons, and aromatic hydrocarbons.
delete In a method for producing a laminate colored steel sheet,
(a) forming a pretreatment layer chemically coated with chromate on a base steel sheet;
(b) applying a solvent-type coating composition on the pretreatment layer to form an undercoat layer;
(c) applying a thermoplastic polyolefin-based coating composition containing 10 to 50% by weight of a modified polyolefin, 0.5 to 30% by weight of an inorganic or rubber, and a residual solvent on the undercoat layer to form an adhesive layer; And
(d) laminating a thermoplastic polyolefin film onto the adhesive layer.
The method according to claim 7, wherein the solvent-type coating composition is at least one selected from the group consisting of polyester-based, epoxy-based, urethane-based, and acrylic-based coatings.
delete 8. The method according to claim 7, wherein the solvent is at least one selected from the group consisting of esters, ethers, alcohols, ketones, aliphatic hydrocarbons, and aromatic hydrocarbons.
delete

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