WO2001034713A1 - Resin-coated steel sheet for fuel tanks of automobile and method of fabricating the same - Google Patents

Resin-coated steel sheet for fuel tanks of automobile and method of fabricating the same Download PDF

Info

Publication number
WO2001034713A1
WO2001034713A1 PCT/KR2000/001297 KR0001297W WO0134713A1 WO 2001034713 A1 WO2001034713 A1 WO 2001034713A1 KR 0001297 W KR0001297 W KR 0001297W WO 0134713 A1 WO0134713 A1 WO 0134713A1
Authority
WO
WIPO (PCT)
Prior art keywords
resin
steel sheet
solution
phr
basis
Prior art date
Application number
PCT/KR2000/001297
Other languages
French (fr)
Inventor
Jae-Ryung Lee
Sam-Kyu Chang
Sang-Geol Noh
Soo-Hyoun Cho
Original Assignee
Pohang Iron & Steel Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pohang Iron & Steel Co., Ltd. filed Critical Pohang Iron & Steel Co., Ltd.
Priority to EP00976423A priority Critical patent/EP1153095A4/en
Priority to JP2001537414A priority patent/JP3543090B2/en
Publication of WO2001034713A1 publication Critical patent/WO2001034713A1/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D161/00—Coating compositions based on condensation polymers of aldehydes or ketones; Coating compositions based on derivatives of such polymers
    • C09D161/04—Condensation polymers of aldehydes or ketones with phenols only
    • C09D161/06—Condensation polymers of aldehydes or ketones with phenols only of aldehydes with phenols
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L61/00—Compositions of condensation polymers of aldehydes or ketones; Compositions of derivatives of such polymers
    • C08L61/04—Condensation polymers of aldehydes or ketones with phenols only
    • C08L61/06—Condensation polymers of aldehydes or ketones with phenols only of aldehydes with phenols
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
    • C23C28/32—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer
    • C23C28/322—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer only coatings of metal elements only
    • C23C28/3225—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer only coatings of metal elements only with at least one zinc-based layer
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
    • C23C28/34—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates
    • C23C28/345—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates with at least one oxide layer

Definitions

  • the present invention relates to an unleaded surface-treated steel sheet for fuel tanks of an automobile, more specifically, a resin-coated steel sheet coated with resin solution on the surface of unleaded surface-treated steel sheet coated with chromate layer and a method of fabricating the same.
  • fuel tanks for storing fuel of an automobile should have resistance to corrosion on its outer surface to be exposed to the atmosphere (hereinafter, referred to as the "cosmetic corrosion resistance”) as well as resistance to corrosion on its inner surface to contact fuel such as gasoline (hereinafter, referred to as the "fuel corrosion resistance”).
  • a fuel tank is usually made by press-forming steel sheets into cup- shaped upper and lower tank bodies, and welding the bodies to each other by resistance welding method such as spot welding or seam welding, or joining method such as soldering or brazing.
  • resistance welding method such as spot welding or seam welding
  • joining method such as soldering or brazing.
  • the resin solution used for coating the unleaded plated steel sheet is phenoxy resin as main solution in the above invention. Since the phenoxy resin has a higher glass transition temperature (Tg) than other resins, it has better characteristics such as cosmetic corrosion resistance and fuel corrosion resistance than epoxy, acryl or urethan resin in a flat plane part which is not subjected to process. However, while seam processing, phenoxy resin has a problem of decreasing cosmetic corrosion resistance and fuel corrosion resistance due to high glass transition temperature in a processing part.
  • Tg glass transition temperature
  • Japanese Patent Laid Open Publication No. Hei2-18981 discloses a way to lower glass transition temperature of phenoxy resin.
  • the above invention relates to a method for reinforcing a coating adhesion between resin and the lower part which bond to the resin by lowering glass transition temperature of phenoxy resin and modifying resin molecules to a rubber.
  • the above method is applied to water-soluble resin, it is difficult to make water-soluble state when modifying it to a rubber, and to add rubber of water-soluble state into phenoxy resin of water-soluble state.
  • the present invention is derived to solve the above problems.
  • the present invention provides a resin solution comprising additives lowering glass transition temperature of phenoxy resin without damaging physical characteristics of resin used for preparing resin-coated steel sheet. It is another object of the present invention to provide a method of fabricating resin-coated steel sheet for fuel tanks of an automobile which can improve adhesion between phenoxy resin and matrix metal by using the resin solution.
  • the present invention provides a resin solution comprising:
  • the present invention provides a resin-coated steel sheet for fuel tanks of an automobile coated with chromate film on cold-rolled steel sheet plated with a zinc (Zn) or zinc-based alloy wherein, the resin solution comprises:
  • the present invention provides a method of fabricating resin-coated steel sheet for fuel tanks of an automobile comprising the steps of coating the resin solution of claim 1 on steel sheet and baking drying it at 160-250 ° C so as to have a coating thickness of 2-10 ⁇ m.
  • the coating process of resin solution is preferably a roll-coating process.
  • the present invention it is possible to provide a steel sheet for fuel tanks which has improved coating adhesion after processing, cosmetic corrosion resistance, and fuel corrosion resistance without using lead by preparing resin solution comprising ethylene-acryl resin and phosphoric ester based on phenoxy resin. Comparing to the prior Pb-Sn plating steel sheet, the present invention can effectively prevent environmental pollution. In addition, quality of a fuel tank of an automobile is improved so that it meets to the requirement of consumers.
  • Fig. 1 is a cross-sectional view of a coating layer of the resin-coated steel sheet for fuel tanks of an automobile.
  • Fig. 2 is a diagram showing a bond between matrix metal and phosphoric ester added into resin solution.
  • Fig. 3 is a diagram of roll-coating equipment which shows coating resin solution on a cold-rolled steel sheet.
  • the resin-coated steel sheet according to the present invention has a structure that zinc or zinc-nickel is plated on a cold- rolled steel sheet and chromate which contains 100 mg/m 2 of chrome is treated on the plated steel sheet, and resin solution of the present invention is coated in the thickness of 2-1 O m.
  • Low-carbon steel sheet having less than or equal to 0.03% of carbon content is used as the cold-rolled steel sheet in the present invention.
  • Zinc (Zn), zinc-nickel (Zn-Ni) alloy, zinc-cobalt (Zn-Co) alloy, zinc- manganese (Zn-Mn) alloy or zinc-chrome (Zn-Cr) alloy may be used as the plating material.
  • zinc-nickel (Zn-Ni) alloy steel sheet is preferably used because it has better cosmetic corrosion resistance than that of zinc-plated steel sheet.
  • Chromate solution applied to zinc-nickel plated steel sheet includes a reactive type, electrolyte type, and coating type, in which coating type is preferable in terms of cosmetic corrosion resistance.
  • coating type is preferable in terms of cosmetic corrosion resistance.
  • the resin solution of the present invention is prepared by adding at least one of ethylene-acryl resin or phosphoric ester to a basic solution mixed with melamine resin and colloidal silica based on phenoxy resin as a main solution. It is preferable to use a main solution of phenoxy resin having a number average molecular weight of 25,000 to 50,000. When the number average molecular weight is less than 25,000, it is difficult to have desired material properties. When the number average molecular weight is more than 50,000, it is impossible to synthesize the resin due to the limitation of synthetic process.
  • Phenoxy resin has excellent cosmetic corrosion resistance and fuel corrosion resistance by the following reasons.
  • phenoxy resin The most characteristic property of phenoxy resin is high glass transition temperature(Tg).
  • glass transition temperature of these In case of urethan, epoxy, and acryl resin, glass transition temperature of these is around or less than 50 ° C, although it depends on the molecular weight. However, glass transition temperature of phenoxy resin is 100 ° C .
  • High glass transition temperature means high movement temperature of resin chain.
  • the resin chains do not show Brown movement below the glass transition temperature, they have primary protecting-effect against outer low molecular corrosion element such as moisture or gasoline. That is, if resin chains show Micro Brown movement, the low molecules easily infiltrate between moving chains so that corrosion elements can easily infiltrate. Therefore, resins with high glass transition temperature have screening effect against matrix metal. Particularly it shows very high screening effect in a flat plane part.
  • Phenoxy resins have the following shortcomings. That is, since resin coating is very hard, if it is subjected to process, it shows lower drawing than a resin with low glass transition temperature. In addition, since phenoxy resin has a weak adhesion with lower metal coating layer, if it is subjected to process harshly, resin coating is cracked and the adhesion of coating become weaken. Furthermore, if the resin is subjected to process more severe, resin coating exfoliates so that corrosion elements easily infiltrate into the metal coating layer of matrix metal, which results in more corrosion. In manufacturing a fuel tank of an automobile, in order to improve formability during processing, press oil is coated before processing and then the oil is removed. However, the oil removing process makes resin hard.
  • poly-alloy or poly-blend comprising other resin with good adhesion and drawing ratio than pure phenoxy resin.
  • the requirements for the other resin forming poly-blend are as follows: First, it has to have compatibility with water-soluble phenoxy resin not to result in gelation or sludge. Second, it does not have influence to the original excellent characteristics of phenoxy resin such as cosmetic corrosion resistance and fuel corrosion resistance and simultaneously it has to lower glass transition temperature of the whole resin, thereby it improves the coating adhesion.
  • the resin which meets the above requirements is ethylene-acryl resin.
  • ethylene-acryl resin There are two methods to add ethylene-acryl resin to phenoxy resin.
  • One is chemical method to bond ethylene-acryl resin to phenoxy resin.
  • the other is physical method.
  • the physical method is preferable.
  • Ethylene-acryl resin used in the present invention has molecular weight of 20,000 - 50,000. This includes 50 - 80 % of ethylene and 50 - 20 % of acryl resin. If acryl resin is comprised less than 20 %, it is impossible to make a soluble state whereas If acryl resin is comprised more than 80 %, the glass transition temperature becomes high and adhesion becomes poor.
  • the content of ethylene-acryl resin is preferably 5 -15phr(parts per hundred resin). If the content is less than 5phr, coating adhesion effect is less whereas if more than 15phr, fuel corrosion resistance decreases.
  • gasoline is a typical carbohydrate compound of carbon and hydrogen, it has very similar structure to ethylene resin comprising carbon and hydrogen, thus gasoline penetrates into ethylene-acryl resin and then is swelled. This is the reason that the fuel corrosion resistance decreases.
  • ethylene resin comprising carbon and hydrogen
  • Fig. 2 shows molecular structure of phosphoric ester. Hydroxyl group of phosphoric ester forms hydrogen-bond with hydrogen atom of water molecule, which prevents infiltrating of moisture and improves cosmetic corrosion resistance. Oxygen of phosphoric ester bonds with metal ion of surface layer and improves coating adhesion.
  • the content of phosphoric ester is preferably 0.5-3.0phr on the basis of phenoxy resin. If content of phosphoric ester is less than 0.5phr, the effect of adhesion decreases. If content of phosphoric ester is more than 3.0phr, there is no effect according to the increase of amount.
  • melamine resin as a hardener can be added to the resin solution of the present invention.
  • the content of melamine resin is 2-15phr on the basis of phenoxy resin. It is preferable to select melamine resin which has high reactivity. If content of melamine is less than 2phr, hardening reaction is not sufficient after resin coating so that desired physical characteristic is not obtained. On the contrary, if content of melamine is more than 15phr, reactions between hardeners themselves occur so that it adversely influences to the physical characteristics of coating layer.
  • colloidal silica is added to improve cosmetic corrosion resistance of resin.
  • the content of colloidal silica is preferably 10-20phr on the basis of phenoxy resin content. If content of colloidal silica is less than 10phr, it is too little to have cosmetic corrosion resistance effect. On the contrary, if content of colloidal silica is more than 20phr, there is no improved effect of cosmetic corrosion resistance relative to the added content of colloidal silica.
  • the resin-coated steel sheet of the present invention is manufactured by treating chromate on zinc or zinc alloy plated steel sheet, baking drying, coating resin solution and baking drying the steel sheet.
  • Thickness of the resin coating which is coated on upper side of chromate layer is preferably 2.0-10.0 ⁇ m. If the thickness is less than 2.0 ⁇ m, the thickness of the coating is too thin to have sufficient cosmetic corrosion resistance and fuel corrosion resistance. On the contrary, if the thickness is more than 10.0 ⁇ m, there is no influence to cosmetic corrosion resistance and fuel corrosion resistance according to increase of the thickness as well as weldability decreases.
  • Baking temperature after coating the resin solution is preferably 160- 250 ° C based on metal temperature(MT). If baking temperature is less than 160 ° C , hardening reaction of the resin is not sufficient to have cosmetic corrosion resistance and fuel corrosion resistance. On the contrary, if the baking temperature is more than 250 ° C , hardening reaction does not occur any longer and loss of calories increases.
  • Coating processes of steel sheet include roll coating, spray, impregnation and so on. It is preferably to use roll coating process in the present invention.
  • Fig.3 shows roll coating equipment used for treating chromate and coating resin solution.
  • the coating process according to fig.3 comprises dipping resin in a drip pan into pick-up-roll(P.U.R), transferring it by a transfer-roll (T.F.R), dipping it into steel sheet in the applicator-roll(A.p.R), and drying in the oven.
  • the amount of resin attached to the steel sheet is regulated by each roll driving direction, rolling speed, and each roll adhesion pressure.
  • the above roll coating process can be applicable to one side or both sides of steel sheet.
  • a composition of phenoxy resin with number average molecular weight of 50,000, 5 phr of melamine resin as a hardener, 15 phr of colloidal silica with particle size 20nm and 2phr of wax is referred to as a standard solution composition unless other specific note.
  • the following method is referred to as a standard method of manufacturing steel sheet: treating chromate on electric zinc and zinc alloy plated steel sheet with plate amount of 30g/m 2 , baking drying so as to make metal temperature of 160 ° C , cooling it, coating resin solution prepared by various composition, baking drying so as to make metal temperature of 190 ° C , and forming resin-coated steel sheet with dried coating thickness of 3 ⁇ m.
  • the resin-coated steel sheet was manufactured by coating the resin solution on the steel sheet plated with zinc of 20-30g/m 2 and treated with chromate of 100mg/m 2 by roll-coating process, baking drying so as to make metal temperature of 190 ° C , water-cooling and forming resin-coated steel sheet with dried coating thickness of 3 ⁇ m.
  • the cosmetic corrosion resistance of the steel sheet prepared by the above process was measured in a processing part by using a salt spray test.
  • a specimen for measurement was prepared by cutting flat plane into 95mm, preparing a cup with diameter of 50mm and height of 25mm, taking out the cup from salt spray after 500 hours, washing with distilled water and drying. According to the amount of occurrence of rust, the grades of cosmetic corrosion resistance were classified in the following way and table 1 showed the result.
  • Circle in circle ( ⁇ ) The area of occurrence of white rust is 5% or less with respect to the total area of a specimen.
  • Triangle ( ⁇ ) The area of occurrence of white rust is in the range of 50-100% with respect to the total area of a specimen.
  • the first mode was to measure exfoliated area of resin after detaching cellophane tape that was attached to around of cup specimen with diameter of 50mm and height 25mm cut from flat plane of 95mm.
  • the second mode was to measure the same method as the first mode after applying ultrasound to 10% caustic soda solution for 3 minutes at 50 ° C and washing. Then, coating adhesion was measured according to the below grades and table 1 showed the result.
  • Fuel corrosion resistance was measured as follows: A flat plane facing to fuel is cut into 95 mm, and formed to cups with diameter of 50 mm and height of 25 nim. Three kinds of solution of 25ml were poured into the cups.
  • the solutions were classified into A type, B type and C type.
  • a type solution regular gasoline was mixed with 5% of sodium chloride (NaCI) aqueous solution.
  • B type solution regular gasoline was mixed with 0.2% of sodium chloride.
  • C type solution For the C type solution,
  • Circle (0 ) The area of occurrence of white rust is in the range of 5- 30% with respect to the total area of a specimen.
  • the above table 1 shows the result of measurement according to the various contents of ethylene-acryl resin as an additive and melamine resin as a hardener.
  • content of ethylene-acryl resin is more than 20phr, coating adhesion and cosmetic corrosion resistance is good but fuel corrosion resistance decreases.
  • ethylene- acryl resin content is less than 5phr, the comparison examples show inferior characteristics to the examples of the present invention.
  • the resin-coated steel sheet was manufactured by coating the resin solution on the steel sheet plated with zinc of 20-30g/m 2 and treated with 100mg/m 2 of chromate by roll-coating process, baking drying so as to make metal temperature of 190 ° C , water-cooling and forming resin-coated steel sheet with dried coating thickness of 3 ⁇ m. After measuring same as Example 1 , the result was shown in table 2.
  • the above table 2 shows the result of measurement according to the various content of phosphoric ester resin as an additive and melamine resin as a hardener.
  • content of phosphoric ester resin is in the range of 0.5-3.0phr, coating adhesion after processing is improved.
  • phosphoric ester content is more than 3.0phr or less than 0.5phr, the comparison examples show inferior characteristics to the examples of the present invention.

Abstract

The present invention relates to a resin-coated steel sheet for fuel tanks of an automobile and a resin solution used for the same. The resin solution of the present invention comprises (a) a main solution of water soluble phenoxy resin having a number average molecular weight of 25,000 to 50,000, (b) 2 to 15 phr of melamine resin on the basis of the main solution, (c) 10 to 20 phr of colloidal silica on the basis of the main solution, and (d) water soluble ethylene-acryl resin containing 50-80 % of ethylene and 50-20 % of acryl resin and having a molecular weight of 20,000 to 50,000, in an amount of 5 to 15 phr on the basis of the main solution; and/or 0.5 to 3.0 phr of phosphoric ester on the basis of the main solution. The resin solution is coated on a cold-rolled steel sheet plated with zinc or zinc alloy over which a chromate layer films, and then dried at a local temperature of 140 to 250 °C to prepare a resin-coated steel sheet for fuel tanks of an automobile.

Description

RESIN-COATED STEEL SHEET FOR FUEL TANKS OF AUTOMOBILE AND METHOD OF FABRICATING THE SAME
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention relates to an unleaded surface-treated steel sheet for fuel tanks of an automobile, more specifically, a resin-coated steel sheet coated with resin solution on the surface of unleaded surface-treated steel sheet coated with chromate layer and a method of fabricating the same.
(b) Description of the Related Art
Generally, it is required that fuel tanks for storing fuel of an automobile should have resistance to corrosion on its outer surface to be exposed to the atmosphere (hereinafter, referred to as the "cosmetic corrosion resistance") as well as resistance to corrosion on its inner surface to contact fuel such as gasoline (hereinafter, referred to as the "fuel corrosion resistance").
A fuel tank is usually made by press-forming steel sheets into cup- shaped upper and lower tank bodies, and welding the bodies to each other by resistance welding method such as spot welding or seam welding, or joining method such as soldering or brazing. In this respect, because two parts are joined each other in a fuel tank, good weldability and good processibility are required for the steel sheet to be applied for use in forming fuel tanks. A temesheet that is a cold-rolled steel sheet plated with lead-tin alloy has widely used as a steel sheet for fuel tanks. However, the temesheet have been limited in its use because it contains lead that causes environmental pollution.
In this connection, extensive researches have been made to develop a surface-treated steel sheet for fuel tanks without using lead. International patent publication No.WO 00/32843 invented by the present inventors discloses a plated steel sheet that does not use lead. The above patent provides an unleaded plated steel sheet coated with resin solution on the surface of zinc or zinc-based alloy plating steel sheet coated with chromate layer to improve cosmetic corrosion resistance and fuel corrosion resistance.
The resin solution used for coating the unleaded plated steel sheet is phenoxy resin as main solution in the above invention. Since the phenoxy resin has a higher glass transition temperature (Tg) than other resins, it has better characteristics such as cosmetic corrosion resistance and fuel corrosion resistance than epoxy, acryl or urethan resin in a flat plane part which is not subjected to process. However, while seam processing, phenoxy resin has a problem of decreasing cosmetic corrosion resistance and fuel corrosion resistance due to high glass transition temperature in a processing part.
In order to improve the problem, there is a way to lower glass transition temperature of phenoxy resin, or to bond phenoxy resin layer and lower chromate layer chemically not to exfoliate the coating during seam processing. Japanese Patent Laid Open Publication No. Hei2-18981 discloses a way to lower glass transition temperature of phenoxy resin. The above invention relates to a method for reinforcing a coating adhesion between resin and the lower part which bond to the resin by lowering glass transition temperature of phenoxy resin and modifying resin molecules to a rubber. However, if the above method is applied to water-soluble resin, it is difficult to make water-soluble state when modifying it to a rubber, and to add rubber of water-soluble state into phenoxy resin of water-soluble state.
SUMMARY OF THE INVENTION Therefore, the present invention is derived to solve the above problems. The present invention provides a resin solution comprising additives lowering glass transition temperature of phenoxy resin without damaging physical characteristics of resin used for preparing resin-coated steel sheet. It is another object of the present invention to provide a method of fabricating resin-coated steel sheet for fuel tanks of an automobile which can improve adhesion between phenoxy resin and matrix metal by using the resin solution.
In order to achieve the above objects, the present invention provides a resin solution comprising:
(a) a main solution of water soluble phenoxy resin having a number average molecular weight of 25,000 to 50,000;
(b) 2 to 15 phr of melamine resin on the basis of the main solution;
(c) 10 to 20 phr of colloidal silica on the basis of the main solution; and
(d) water soluble ethylene-acryl resin containing 50-80% of ethylene and 50-20% of acryl resin and having a molecular weight of 20,000 to 50,000, in an amount of 5 to 15 phr on the basis of said main solution; and/or 0.5 to 3.0 phr of phosphoric ester on the basis of the main solution. In order to achieve the above objects, the present invention provides a resin-coated steel sheet for fuel tanks of an automobile coated with chromate film on cold-rolled steel sheet plated with a zinc (Zn) or zinc-based alloy wherein, the resin solution comprises:
(e) a main solution of water soluble phenoxy resin having a number average molecular weight of 25,000 to 50,000;
(f) 2 to 15 phr of melamine resin on the basis of the main solution;
(g) 10 to 20 phr of colloidal silica on the basis of the main solution; and
(h) water soluble ethylene-acryl resin containing 50-80% of ethylene and 50-20% of acryl resin and having a molecular weight of 20,000 to 50,000, in an amount of 5 to 15 phr on the basis of the main solution; and/or 0.5 to 3.0 phr of phosphoric ester on the basis of the main solution, said resin solution coated on the cold-rolled steel sheet with a coating thickness of 2-10 μm after drying the resin coating. In order to achieve the above objects, the present invention provides a method of fabricating resin-coated steel sheet for fuel tanks of an automobile comprising the steps of coating the resin solution of claim 1 on steel sheet and baking drying it at 160-250 °C so as to have a coating thickness of 2-10 μm. The coating process of resin solution is preferably a roll-coating process.
According to the present invention, it is possible to provide a steel sheet for fuel tanks which has improved coating adhesion after processing, cosmetic corrosion resistance, and fuel corrosion resistance without using lead by preparing resin solution comprising ethylene-acryl resin and phosphoric ester based on phenoxy resin. Comparing to the prior Pb-Sn plating steel sheet, the present invention can effectively prevent environmental pollution. In addition, quality of a fuel tank of an automobile is improved so that it meets to the requirement of consumers.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a cross-sectional view of a coating layer of the resin-coated steel sheet for fuel tanks of an automobile.
Fig. 2 is a diagram showing a bond between matrix metal and phosphoric ester added into resin solution. Fig. 3 is a diagram of roll-coating equipment which shows coating resin solution on a cold-rolled steel sheet.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferred embodiments of this invention will be explained with reference to the accompanying drawing. As shown in Fig. 1 , the resin-coated steel sheet according to the present invention has a structure that zinc or zinc-nickel is plated on a cold- rolled steel sheet and chromate which contains 100 mg/m2 of chrome is treated on the plated steel sheet, and resin solution of the present invention is coated in the thickness of 2-1 O m.
Low-carbon steel sheet having less than or equal to 0.03% of carbon content is used as the cold-rolled steel sheet in the present invention.
Zinc (Zn), zinc-nickel (Zn-Ni) alloy, zinc-cobalt (Zn-Co) alloy, zinc- manganese (Zn-Mn) alloy or zinc-chrome (Zn-Cr) alloy may be used as the plating material. In the present invention, zinc-nickel (Zn-Ni) alloy steel sheet is preferably used because it has better cosmetic corrosion resistance than that of zinc-plated steel sheet.
Chromate solution applied to zinc-nickel plated steel sheet includes a reactive type, electrolyte type, and coating type, in which coating type is preferable in terms of cosmetic corrosion resistance. When the chromate solution is applied to the steel sheet, it can be plated on one side or both sides. It is preferable to coat on both sides.
However, in case of resin solution, it can be alternatively coated on one side or both sides depending on the needs of consumer. Such an alternation depends on the welding condition when the resin- coated steel sheet is used for manufacturing fuel tanks. That is, in case of high current condition that is easy for welding and frequent replacing of electrolyte, it is preferable to use steel sheet coated on both sides whereas in case of low current condition and infrequent replacing of electrolyte, it is preferable to use steel sheet coated on one side.
When manufacturing a fuel tank by a steel sheet coated with resin on one side, it is preferable to weld the tank by placing the coated side to face to fuel side and chromate-coated side which is not coated with resin to face to outer side. Thus, it makes welding easily because the welding electrolyte does not contact with resin part. In addition, if necessary, paint is applied to a side which is not coated with resin in the thickness of about 100 micrometer so to reinforce corrosion resistance of fuel tank, thus, it has little influence to corrosion resistance.
Hereinafter, the resin solution used in the resin-coated steel sheet of the present invention will be explained in detail.
The resin solution of the present invention is prepared by adding at least one of ethylene-acryl resin or phosphoric ester to a basic solution mixed with melamine resin and colloidal silica based on phenoxy resin as a main solution. It is preferable to use a main solution of phenoxy resin having a number average molecular weight of 25,000 to 50,000. When the number average molecular weight is less than 25,000, it is difficult to have desired material properties. When the number average molecular weight is more than 50,000, it is impossible to synthesize the resin due to the limitation of synthetic process.
Phenoxy resin has excellent cosmetic corrosion resistance and fuel corrosion resistance by the following reasons.
The most characteristic property of phenoxy resin is high glass transition temperature(Tg). In case of urethan, epoxy, and acryl resin, glass transition temperature of these is around or less than 50 °C, although it depends on the molecular weight. However, glass transition temperature of phenoxy resin is 100°C . High glass transition temperature means high movement temperature of resin chain. Thus, since the resin chains do not show Brown movement below the glass transition temperature, they have primary protecting-effect against outer low molecular corrosion element such as moisture or gasoline. That is, if resin chains show Micro Brown movement, the low molecules easily infiltrate between moving chains so that corrosion elements can easily infiltrate. Therefore, resins with high glass transition temperature have screening effect against matrix metal. Particularly it shows very high screening effect in a flat plane part. Phenoxy resins, however, have the following shortcomings. That is, since resin coating is very hard, if it is subjected to process, it shows lower drawing than a resin with low glass transition temperature. In addition, since phenoxy resin has a weak adhesion with lower metal coating layer, if it is subjected to process harshly, resin coating is cracked and the adhesion of coating become weaken. Furthermore, if the resin is subjected to process more severe, resin coating exfoliates so that corrosion elements easily infiltrate into the metal coating layer of matrix metal, which results in more corrosion. In manufacturing a fuel tank of an automobile, in order to improve formability during processing, press oil is coated before processing and then the oil is removed. However, the oil removing process makes resin hard. Thus, it cannot expect to have original screening effect because there is damage by the oil removing process in a weak adhesion point. Accordingly, it is preferable to use poly-alloy or poly-blend comprising other resin with good adhesion and drawing ratio than pure phenoxy resin.
The requirements for the other resin forming poly-blend are as follows: First, it has to have compatibility with water-soluble phenoxy resin not to result in gelation or sludge. Second, it does not have influence to the original excellent characteristics of phenoxy resin such as cosmetic corrosion resistance and fuel corrosion resistance and simultaneously it has to lower glass transition temperature of the whole resin, thereby it improves the coating adhesion.
The resin which meets the above requirements is ethylene-acryl resin. There are two methods to add ethylene-acryl resin to phenoxy resin.
One is chemical method to bond ethylene-acryl resin to phenoxy resin. The other is physical method. The physical method is preferable.
Since ethylene-acryl resin used in the present invention is synthesized in gas phase and already water-soluble state, it is impossible to synthesize phenoxy resin of water-soluble state and ethylene-acryl resin of water- soluble state. This is why the chemical method is not appropriate in the present invention.
Ethylene-acryl resin used in the present invention has molecular weight of 20,000 - 50,000. This includes 50 - 80 % of ethylene and 50 - 20 % of acryl resin. If acryl resin is comprised less than 20 %, it is impossible to make a soluble state whereas If acryl resin is comprised more than 80 %, the glass transition temperature becomes high and adhesion becomes poor. The content of ethylene-acryl resin is preferably 5 -15phr(parts per hundred resin). If the content is less than 5phr, coating adhesion effect is less whereas if more than 15phr, fuel corrosion resistance decreases. Since gasoline is a typical carbohydrate compound of carbon and hydrogen, it has very similar structure to ethylene resin comprising carbon and hydrogen, thus gasoline penetrates into ethylene-acryl resin and then is swelled. This is the reason that the fuel corrosion resistance decreases. In order to improve coating adhesion of resin, there is a method to introduce additives other than making poly-blend.
The role of additives reinforces adhesion between phenoxy resin and lower chromate layer during seam processing. Mechanism of phosphoric ester of the additive used in the present invention is explained referring fig. 2. Fig. 2 shows molecular structure of phosphoric ester. Hydroxyl group of phosphoric ester forms hydrogen-bond with hydrogen atom of water molecule, which prevents infiltrating of moisture and improves cosmetic corrosion resistance. Oxygen of phosphoric ester bonds with metal ion of surface layer and improves coating adhesion. The content of phosphoric ester is preferably 0.5-3.0phr on the basis of phenoxy resin. If content of phosphoric ester is less than 0.5phr, the effect of adhesion decreases. If content of phosphoric ester is more than 3.0phr, there is no effect according to the increase of amount.
In order to complement shortcoming of phenoxy resin, it is possible to combine both ethylene-acryl resin and phosphoric ester or combine optionally. In case of combining both of them, glass transition temperature of phenoxy resin lowers and ions of phosphoric ester bonds with metal, which improve coating adhesion after processing of phenoxy resin.
Furthermore, melamine resin as a hardener can be added to the resin solution of the present invention.
The content of melamine resin is 2-15phr on the basis of phenoxy resin. It is preferable to select melamine resin which has high reactivity. If content of melamine is less than 2phr, hardening reaction is not sufficient after resin coating so that desired physical characteristic is not obtained. On the contrary, if content of melamine is more than 15phr, reactions between hardeners themselves occur so that it adversely influences to the physical characteristics of coating layer.
Further additive added to the resin solution of the present invention is colloidal silica. Colloidal silica is added to improve cosmetic corrosion resistance of resin. The content of colloidal silica is preferably 10-20phr on the basis of phenoxy resin content. If content of colloidal silica is less than 10phr, it is too little to have cosmetic corrosion resistance effect. On the contrary, if content of colloidal silica is more than 20phr, there is no improved effect of cosmetic corrosion resistance relative to the added content of colloidal silica.
Hereinafter, a method of fabricating resin-coated steel sheet using resin solution of the present invention is explained.
The resin-coated steel sheet of the present invention is manufactured by treating chromate on zinc or zinc alloy plated steel sheet, baking drying, coating resin solution and baking drying the steel sheet.
Thickness of the resin coating which is coated on upper side of chromate layer is preferably 2.0-10.0 μm. If the thickness is less than 2.0 μm, the thickness of the coating is too thin to have sufficient cosmetic corrosion resistance and fuel corrosion resistance. On the contrary, if the thickness is more than 10.0 μm, there is no influence to cosmetic corrosion resistance and fuel corrosion resistance according to increase of the thickness as well as weldability decreases.
Baking temperature after coating the resin solution is preferably 160- 250 °C based on metal temperature(MT). If baking temperature is less than 160°C , hardening reaction of the resin is not sufficient to have cosmetic corrosion resistance and fuel corrosion resistance. On the contrary, if the baking temperature is more than 250 °C , hardening reaction does not occur any longer and loss of calories increases.
Coating processes of steel sheet include roll coating, spray, impregnation and so on. It is preferably to use roll coating process in the present invention.
Fig.3 shows roll coating equipment used for treating chromate and coating resin solution. The coating process according to fig.3 comprises dipping resin in a drip pan into pick-up-roll(P.U.R), transferring it by a transfer-roll (T.F.R), dipping it into steel sheet in the applicator-roll(A.p.R), and drying in the oven. The amount of resin attached to the steel sheet is regulated by each roll driving direction, rolling speed, and each roll adhesion pressure.
In the present invention, the above roll coating process can be applicable to one side or both sides of steel sheet.
Now, preferred embodiments are suggested to help the apparent understanding of the present invention. The below embodiments are provided for the sake of clear understanding only and the present invention is not limited thereto.
Embodiment
Example 1
A composition of phenoxy resin with number average molecular weight of 50,000, 5 phr of melamine resin as a hardener, 15 phr of colloidal silica with particle size 20nm and 2phr of wax is referred to as a standard solution composition unless other specific note. In addition, the following method is referred to as a standard method of manufacturing steel sheet: treating chromate on electric zinc and zinc alloy plated steel sheet with plate amount of 30g/m2, baking drying so as to make metal temperature of 160 °C , cooling it, coating resin solution prepared by various composition, baking drying so as to make metal temperature of 190°C , and forming resin-coated steel sheet with dried coating thickness of 3μm.
After preparing resin solution by mixing ethylene-acryl resin of which weight ratio is 80:20 of ethylene to acryl with the above standard solution according to the content of below table 1 , the resin-coated steel sheet was manufactured by coating the resin solution on the steel sheet plated with zinc of 20-30g/m2 and treated with chromate of 100mg/m2 by roll-coating process, baking drying so as to make metal temperature of 190°C , water-cooling and forming resin-coated steel sheet with dried coating thickness of 3μm. The cosmetic corrosion resistance of the steel sheet prepared by the above process was measured in a processing part by using a salt spray test. A specimen for measurement was prepared by cutting flat plane into 95mm, preparing a cup with diameter of 50mm and height of 25mm, taking out the cup from salt spray after 500 hours, washing with distilled water and drying. According to the amount of occurrence of rust, the grades of cosmetic corrosion resistance were classified in the following way and table 1 showed the result.
Circle in circle (©): The area of occurrence of white rust is 5% or less with respect to the total area of a specimen. Circle (0 ): The area of occurrence of white rust is in the range of 5-
30% with respect to the total area of a specimen.
Square (G ): The area of occurrence of white rust is in the range of 30-50% with respect to the total area of a specimen.
Triangle (Δ): The area of occurrence of white rust is in the range of 50-100% with respect to the total area of a specimen. In addition, in order to measure coating adhesion after processing, two types of mode were used. The first mode was to measure exfoliated area of resin after detaching cellophane tape that was attached to around of cup specimen with diameter of 50mm and height 25mm cut from flat plane of 95mm. The second mode was to measure the same method as the first mode after applying ultrasound to 10% caustic soda solution for 3 minutes at 50 °C and washing. Then, coating adhesion was measured according to the below grades and table 1 showed the result.
Circle in circle (©): The exfoliated area is 0%. Circle (0 ): The exfoliated area is 1 -5%.
Square (D ): The exfoliated area is 5-10%. Triangle (Δ): The exfoliated area is 10-20%. X: The exfoliated area is more than 20%.
Fuel corrosion resistance was measured as follows: A flat plane facing to fuel is cut into 95 mm, and formed to cups with diameter of 50 mm and height of 25 nim. Three kinds of solution of 25ml were poured into the cups.
Thereafter, the opening portions of the cups were covered with transparent glass plates by interposing circular "O" rings and fixed with clamp to prevent gasoline from leaking. The solutions were classified into A type, B type and C type. For the A type solution, regular gasoline was mixed with 5% of sodium chloride (NaCI) aqueous solution. For the B type solution, regular gasoline was mixed with 0.2% of sodium chloride. For the C type solution,
85% of regular gasoline was mixed with 14% of methanol and distilled water containing 60ppm of formic acid and 20 ppm of Cl" ion. In order to simulate driving situation of automobile, rocking equipment was used such that the solution contained in the cup was in rocking motion. The cups were allowed to stand for 4 months. Then, the cups were taken out, washed by distilled water, and dried. According to the amount of occurrence of rust, the grades of fuel corrosion resistance were classified in the following way and table 1 showed the result. Circle in circle (©): The area of occurrence of white rust is 5% or less with respect to the total area of a specimen.
Circle (0 ): The area of occurrence of white rust is in the range of 5- 30% with respect to the total area of a specimen. Square (Q ): The area of occurrence of white rust is in the range of
30-50% with respect to the total area of a specimen.
Triangle (Δ): The area of occurrence of white rust is in the range of 50-100% with respect to the total area of a specimen.
X: Red rust occurred.
Table 1
Figure imgf000015_0001
The above table 1 shows the result of measurement according to the various contents of ethylene-acryl resin as an additive and melamine resin as a hardener. As can be seen in table 1 , when content of ethylene-acryl resin is more than 20phr, coating adhesion and cosmetic corrosion resistance is good but fuel corrosion resistance decreases. In addition, when ethylene- acryl resin content is less than 5phr, the comparison examples show inferior characteristics to the examples of the present invention.
Example 2
After preparing resin solution by mixing phosphoric ester as an additive with the above standard solution according to the content of below table 2, the resin-coated steel sheet was manufactured by coating the resin solution on the steel sheet plated with zinc of 20-30g/m2 and treated with 100mg/m2 of chromate by roll-coating process, baking drying so as to make metal temperature of 190°C , water-cooling and forming resin-coated steel sheet with dried coating thickness of 3μm. After measuring same as Example 1 , the result was shown in table 2.
Table2
Figure imgf000017_0001
The above table 2 shows the result of measurement according to the various content of phosphoric ester resin as an additive and melamine resin as a hardener. As can be seen in table 2, when content of phosphoric ester resin is in the range of 0.5-3.0phr, coating adhesion after processing is improved. However, when phosphoric ester content is more than 3.0phr or less than 0.5phr, the comparison examples show inferior characteristics to the examples of the present invention.
Meanwhile, when both phosphoric ester and ethylene-acryl resin as additives are mixed to the resin solution of the present invention, it shows the same or excellent effect than that of each additive is mixed as the above examples.

Claims

WHAT IS CLAIMED IS:
1. A resin solution used for preparing resin-coated steel sheet for fuel tanks of an automobile comprising:
(i) a main solution of water soluble phenoxy resin having a number average molecular weight of 25,000 to 50,000;
(j) 2 to 15 phr of melamine resin on the basis of said main solution; (k) 10 to 20 phr of colloidal silica on the basis of said main solution; and
(I) water soluble ethylene-acryl resin containing 50-80% of ethylene and 50-20% of acryl resin and having a molecular weight of 20,000 to 50,000, in an amount of 5 to 15 phr on the basis of said main solution; and/or 0.5 to 3.0 phr of phosphoric ester on the basis of said main solution.
2. A resin-coated steel sheet for fuel tanks of an automobile coated with chromate film on cold-rolled steel sheet plated with a zinc (Zn) or zinc- based alloy wherein, the resin solution comprises:
(m) a main solution of water soluble phenoxy resin having a number average molecular weight of 25,000 to 50,000;
(n) 2 to 15 phr of melamine resin on the basis of said main solution; (o) 10 to 20 phr of colloidal silica on the basis of said main solution; and
(p) water soluble ethylene-acryl resin containing 50-80% of ethylene and 50-20% of acryl resin and having a molecular weight of 20,000 to 50,000, in an amount of 5 to 15 phr on the basis of said main solution; and/or 0.5 to 3.0 phr of phosphoric ester on the basis of said main solution, said resin solution coated on said cold-rolled steel sheet with a thickness of 2-10 μm after drying of the resin coating.
3. A method of fabricating resin-coated steel sheet for a fuel tank of an automobile comprising the steps of: coating the resin solution of claim 1 on steel sheet; and baking drying it at 160-250 °C so as to have a coating thickness of 2- 10 μm.
4. The method of fabricating resin-coated steel sheet of claim 3, wherein coating process of said resin solution is a roll-coating process.
PCT/KR2000/001297 1999-11-12 2000-11-13 Resin-coated steel sheet for fuel tanks of automobile and method of fabricating the same WO2001034713A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP00976423A EP1153095A4 (en) 1999-11-12 2000-11-13 Resin-coated steel sheet for fuel tanks of automobile and method of fabricating the same
JP2001537414A JP3543090B2 (en) 1999-11-12 2000-11-13 Resin-coated steel sheet for automobile fuel tank and method of manufacturing the same

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR1999/50110 1999-11-12
KR10-1999-0050110A KR100402014B1 (en) 1999-11-12 1999-11-12 A resin coating solution for coated steel sheets with exellent adhesion after forming and a method for manufacturing resin coating steel sheets by using it

Publications (1)

Publication Number Publication Date
WO2001034713A1 true WO2001034713A1 (en) 2001-05-17

Family

ID=19619722

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2000/001297 WO2001034713A1 (en) 1999-11-12 2000-11-13 Resin-coated steel sheet for fuel tanks of automobile and method of fabricating the same

Country Status (5)

Country Link
EP (1) EP1153095A4 (en)
JP (1) JP3543090B2 (en)
KR (1) KR100402014B1 (en)
CN (1) CN1340087A (en)
WO (1) WO2001034713A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1156090A2 (en) * 2000-05-17 2001-11-21 DaimlerChrysler AG Coating solution from several precursors for the preparation of a cured coating for preferably metallic surfaces
US8663793B2 (en) 2006-12-27 2014-03-04 Posco Excellent heat-dissipating black resin composition, method for treating a zinc coated steel sheet using the same and steel sheet treated thereby
TWI480422B (en) * 2013-10-07 2015-04-11 China Steel Corp A device and method for cleaning the mouth of a zinc tank

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100423441B1 (en) * 1999-12-28 2004-03-19 주식회사 포스코 A preparing method of resin coating solution for fuel tank body with excellent solution stability, the resin coating solution prepared from it and a method for manufacturing organic resin coated steel sheets having enhanced anti-alkali resistance using it
KR100508504B1 (en) * 2000-11-22 2005-08-17 주식회사 포스코 Resin coating solution for fuel tank with excellent welding properties and resin coated steel sheet by using it
KR100498094B1 (en) * 2000-12-21 2005-07-01 주식회사 포스코 A coating composition for fuel container having corrosion resistance adhesive and a coating method by using them
KR20030053762A (en) * 2001-12-24 2003-07-02 주식회사 포스코 A Coating Composition for Fingerprint Resistance Steel Plate Having Superior Chemical Resistance and Adhesive
KR100544725B1 (en) * 2001-12-26 2006-01-24 주식회사 포스코 Manufacturing method of resin coated steel sheet for automotive fuel tank with excellent corrosion resistance and fuel resistance
KR100928834B1 (en) * 2002-12-27 2009-11-27 주식회사 포스코 Manufacturing method of resin-coated steel sheet for automobile fuel tank
JP4774442B2 (en) * 2005-12-27 2011-09-14 ポスコ Chromium-free surface-treated steel sheet for fuel tank and manufacturing method thereof
KR100804934B1 (en) * 2006-12-27 2008-02-20 주식회사 포스코 Excellent heat-dissipating black resin composition, method for treating a steel sheet using the same and steel sheet treated thereby
CN101250312B (en) * 2008-04-01 2010-06-16 长春依多科化工有限公司 Foaming sound-proof acrylic resin vehicle bottom protective plastisol and preparation method thereof
KR101792240B1 (en) * 2015-09-18 2017-10-31 주식회사 포스코 Composition for surface-treating a single-side-plated steel sheet, surface-treated steel sheet using the same composition, and the method for surface-treatent sheet using the sam composition

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05156582A (en) * 1991-06-24 1993-06-22 Nippon Steel Corp Coating composition for galvanized steel wire and galvanized steel cable wire coated therewith
JPH06146010A (en) * 1992-11-04 1994-05-27 Nippon Steel Corp Galvanized steel wire for resin coated cable
US5397638A (en) * 1990-11-28 1995-03-14 Kabushiki Kaisha Kobe Seiko Sho Resin-coated steel sheet having good electrocoatability and weldability

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4391855A (en) * 1980-08-25 1983-07-05 Depor Industries Corrosion resistant coating and method for coating metal substrate
KR100193146B1 (en) * 1990-07-20 1999-06-15 월터 클리웨인, 한스-피터 위트린 Stabilized Monomer Composition
US5578669A (en) * 1993-12-24 1996-11-26 Nippon Paint Co., Ltd. Water-based polyurethane coating composition
JPH0885187A (en) * 1994-09-20 1996-04-02 Nippon Paint Co Ltd Laminated metallic plate and manufacture thereof
US5707704A (en) * 1994-12-27 1998-01-13 Kimoto Co., Ltd. Masking films

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5397638A (en) * 1990-11-28 1995-03-14 Kabushiki Kaisha Kobe Seiko Sho Resin-coated steel sheet having good electrocoatability and weldability
JPH05156582A (en) * 1991-06-24 1993-06-22 Nippon Steel Corp Coating composition for galvanized steel wire and galvanized steel cable wire coated therewith
JPH06146010A (en) * 1992-11-04 1994-05-27 Nippon Steel Corp Galvanized steel wire for resin coated cable

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP1153095A4 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1156090A2 (en) * 2000-05-17 2001-11-21 DaimlerChrysler AG Coating solution from several precursors for the preparation of a cured coating for preferably metallic surfaces
EP1156090A3 (en) * 2000-05-17 2002-11-06 DaimlerChrysler AG Coating solution from several precursors for the preparation of a cured coating for preferably metallic surfaces
US6815495B2 (en) 2000-05-17 2004-11-09 Daimlerchrysler Ag Coating of melamine, epoxy, urethane or alkyd resin with phenolic resin binder
US8663793B2 (en) 2006-12-27 2014-03-04 Posco Excellent heat-dissipating black resin composition, method for treating a zinc coated steel sheet using the same and steel sheet treated thereby
TWI480422B (en) * 2013-10-07 2015-04-11 China Steel Corp A device and method for cleaning the mouth of a zinc tank

Also Published As

Publication number Publication date
KR20010046371A (en) 2001-06-15
EP1153095A4 (en) 2003-04-09
EP1153095A1 (en) 2001-11-14
JP2003514095A (en) 2003-04-15
KR100402014B1 (en) 2003-10-17
JP3543090B2 (en) 2004-07-14
CN1340087A (en) 2002-03-13

Similar Documents

Publication Publication Date Title
EP1051539B1 (en) Surface-treated steel sheet for fuel tanks and method of fabricating same
EP0453374B1 (en) Improved corrosion-resistant surface coated steel sheet
KR101008081B1 (en) Surface treated cr-free steel sheet for used in fuel tank, preparing method thereof and treatment composition therefor
KR930001015B1 (en) Zinc alloy-plated corrosion preventive steel sheet having an organic coating layer there on and a method for making the same
EP0385362A1 (en) Steel plate with organic coating having improved corrosion resistance
US6797372B2 (en) Resin-coated steel for fuel tanks of automobile and method for manufacturing the same
EP1153095A1 (en) Resin-coated steel sheet for fuel tanks of automobile and method of fabricating the same
KR100396084B1 (en) Surface-Treated Steel Sheet for Automotive Fuel Tanks and Method of Fabricating thereof
JP2000239854A (en) High corrosion resistant steel sheet for fuel tank
EP1165858B1 (en) Surface-treated steel sheet coated with chromate film for fuel tanks and method of fabricating the same
KR100643355B1 (en) Steel Sheet for Automobile Fuel Tank with Excellent Corrosion Resistance and Adhesive and Manufacturing Process Thereof
JP3847921B2 (en) Steel plate for high corrosion resistant fuel tank
KR100833053B1 (en) Cr-free and resin surfaced treated steel sheet, preparing method thereof and resin composition therefor
JP3934762B2 (en) Steel plate for high corrosion resistant fuel tank
JP2712924B2 (en) Zinc-nickel-chromium alloy electroplated steel sheet with excellent corrosion resistance, plating adhesion, chemical conversion treatment and coating film adhesion
KR100544725B1 (en) Manufacturing method of resin coated steel sheet for automotive fuel tank with excellent corrosion resistance and fuel resistance
JPH10278172A (en) Steel panel for highly corrosion-resistant fuel tank
KR20050070306A (en) Resin solution being coated on steel sheet for the gas tank of a car and manufacturing method of this steel sheet
JPH10278173A (en) Steel panel for highly corrosion-resistant fuel tank
JPH10337805A (en) Steel sheet for highly corrosion-resistant fuel tank
JPH10315382A (en) Steel sheet of high corrosion resistance for fuel tank
KR20040058490A (en) Heterogeneous resin coated steel sheet for auto body
MXPA98010414A (en) Steel plate for highly corrosion-resistant fuel tank
JPH10235787A (en) Highly corrosion-resistant fuel tank steel plate

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 00803601.2

Country of ref document: CN

AK Designated states

Kind code of ref document: A1

Designated state(s): CN IN JP US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR

WWE Wipo information: entry into national phase

Ref document number: 09869880

Country of ref document: US

Ref document number: IN/PCT/2001/00613/DE

Country of ref document: IN

121 Ep: the epo has been informed by wipo that ep was designated in this application
ENP Entry into the national phase

Ref document number: 2001 537414

Country of ref document: JP

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 2000976423

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 2000976423

Country of ref document: EP

WWW Wipo information: withdrawn in national office

Ref document number: 2000976423

Country of ref document: EP