JP6044287B2 - Method for manufacturing metal fuel container - Google Patents

Description

The present invention relates to the production how excellent metallic fuel container corrosion resistance after press forming, in particular, long-term inner surface capable automobile to exert corrosion resistance, motorcycles for, machinery, etc. It relates to the production how metallic fuel container in.

  For metal fuel containers for automobiles, motorcycles, machines, etc., Pb-Sn alloy-plated steel sheets with excellent internal and external surface corrosion resistance, workability, solderability (weldability), etc. have been used as fuel tank materials. Used mainly as a fuel tank for automobiles.

  In addition, as disclosed in, for example, Patent Document 1, Sn—Zn alloy-plated steel sheets have been mainly manufactured by an electroplating method in which electrolysis is performed in an aqueous solution containing Zn and Sn ions. Sn—Zn alloy-plated steel sheets mainly composed of Sn are excellent in corrosion resistance and solderability, and have been widely used for electronic parts and the like. In recent years, it has been found that this Sn—Zn plated steel sheet has excellent characteristics for use in automobile fuel tanks. For example, Patent Document 2 and Patent Document 3 disclose a molten Sn—Zn plated steel sheet having excellent corrosion resistance and solderability. Has been.

Japanese Patent Laid-Open No. 52-130438 JP-A-8-269733 JP-A-8-269734 Japanese Patent Laid-Open No. 9-241866 JP 2005-153337 A JP 2011-11803 A JP 2010-208154 A

  Pb—Sn alloy-plated steel sheets that have been used as metal materials for fuel containers for automobiles have been used habitually due to recognition of various excellent properties (for example, workability, tank inner surface corrosion resistance, solderability, seam weldability, etc.). However, with the recent increase in recognition of the global environment, it is shifting to the direction of Pb-free. The above-described molten Sn—Zn-plated steel sheet certainly has excellent corrosion resistance, workability, and solderability, and has become the mainstream metal material for fuel containers.

  However, recently, further improvement in corrosion resistance on the inner surface side of the fuel tank has been demanded. Even with the above-mentioned hot-dip Sn-Zn plated steel sheets, the application of biofuels that are susceptible to deterioration can lead to a short period of time until red rust occurs in the generated organic acid environment, which can cause problems such as perforations and filter clogging. The reliability of the metal fuel container material is low.

  In order to solve this problem, it is conceivable to insulate by setting a resin layer such as a paint on the inner side of the metal fuel container. In Patent Document 4, a conductive resin coating layer is plated, and in Patent Document 5, a resin coating layer is plated. A precoat material provided on the surface has been proposed.

  However, in the pre-coating material, it is applied to parts other than the necessary part, resulting in poor economic efficiency, and it is necessary to add WAX to the film in order to improve processability, and the resin can be completely cross-linked. Since this is not possible, the barrier property of the film and the adhesion to the substrate are not sufficient. In addition, when the container is welded, the place where the coating film is applied needs to be peeled off in order to energize, thus hindering the productivity of the fuel container.

  Also, Patent Documents 6 and 7 propose that a polyester-based paint is applied to the metal surface after pressing, but sufficient coating film adhesion can be secured in the recent severe environment of fuel tanks. Absent.

Accordingly, the present invention is to solve the above problems in the prior art points, and aims to provide a manufacturing how excellent metallic fuel container corrosion resistance and solvent resistance.

The present inventors apply a specified fluororubber-based paint with a specific film thickness to the surface of the metal plate after pressing corresponding to the inner surface of the metal fuel container, thereby providing a metal fuel container having excellent corrosion resistance and solvent resistance. It was found that it can be obtained.
The present invention has been completed based on such knowledge, and the gist of the present invention is as follows.

(1) On the surface of the post-pressed metal plate corresponding to the inner surface of the metal fuel container, the viscosity at 25 ° C. is 10 Pa · s or less, the surface tension is 40 mN / m or less, and an adhesiveness imparting agent is used as a coating composition. based on the total mass of the object as viewed contains 0.1 to 10 mass%, and the fluorine-containing rubber paint containing 0.1 to 20 parts by mass of the fluororubber 100 parts by weight of vulcanizing agent on a solids basis, A method for producing a metallic fuel container, wherein the coating film is formed to have a thickness of 1 to 2000 μm .

  According to the present invention, it is possible to provide a method for producing a metallic fuel container which is excellent in corrosion resistance and excellent in solvent resistance. Therefore, even if organic acid is generated in a fuel container using a metal plate or foreign matter such as sludge is attached, the metal surface is isolated from the corrosive environment by the coating film, so that corrosion in the fuel container is achieved. Can be suppressed for a long time. Therefore, it can be said that the present invention is an industrially extremely valuable invention.

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

  The present invention relates to a surface of a post-press metal plate corresponding to the inner surface of a metal fuel container, having a viscosity at 25 ° C. of 10 Pa · s or less, a surface tension of 40 mN / m or less, and an adhesion-imparting agent A method for producing a metallic fuel container, comprising forming a fluororubber coating material containing 0.1 to 10% by mass based on the total mass of the composition as a coating film in an amount of 1 to 2000 μm.

  For the metal plate used in the present invention, generally known metal materials can be used. This metal material may be an alloy material. Examples of such a metal material include a steel plate, a stainless steel plate, an aluminum plate, an aluminum alloy plate, a titanium plate, and a copper plate. The surface of these materials may be generally subjected to known plating. Examples of the type of plating include zinc plating, aluminum plating, copper plating, nickel plating, and tin plating. The plating applied to the surface of the metal material may be an alloy plating of these. When using steel plates, hot dip galvanized steel plates, electrogalvanized steel plates, zinc-nickel alloy plated steel plates, hot galvanized steel plates, aluminum plated steel plates, aluminum-zinc alloyed steel plates, tin-zinc plating, etc. Generally known steel plates and plated steel plates can be applied. Among these, the combination with the tin-zinc plating that has the most excellent corrosion resistance in the fuel container is desirable because the effect of improving the corrosion resistance is most remarkable.

  As the chemical conversion treatment for the metal plate used in the present invention, zinc phosphate chemical conversion treatment, coating chromate treatment, electrolytic chromic acid treatment, reaction chromate treatment, chromate-free chemical conversion treatment, or the like can be used. As the non-chromate chemical conversion treatment, those treated with an aqueous solution containing trivalent chromium, silane coupling agent, zirconium compound, titanium compound, tannin or tannic acid, resin, silica, etc. are known. 53-9238, JP-A-9-241576, JP-A-2001-89868, JP-A-2001-316845, JP-A-2002-60959, JP-A-2002-38280, JP-A-2002- You may use the well-known technique described in 266081 gazette, Unexamined-Japanese-Patent No. 2003-253464, etc. These chemical conversion treatments include commercially available chemical conversion treatment agents such as chromate treatment “ZM-1300AN” manufactured by Nippon Parkerizing Co., Ltd., chromate-free chemical conversion treatment “CT-E300N” manufactured by Nippon Parkerizing Co., Ltd., and trivalent chromium manufactured by Nippon Paint Co., Ltd. It can be used by using the system chemical conversion treatment “Surf Coat TMNRC1000” or the like.

  The fluororubber coating composition (A) applied to the surface of the metal plate after pressing corresponding to the inner surface of the metal fuel container of the present invention comprises a fluororubber, an adhesion-imparting agent, and other components (vulcanizer, Sulfur auxiliary, filler, colorant, acid acceptor, dispersant, medium (organic solvent / water), stabilizer) are mixed.

  The fluororubber coating composition (A) needs to have a viscosity at 25 ° C. of 10 Pa · s or less and a surface tension of 40 mN / m or less in order to ensure adhesion to the metal plate. . The lower the surface tension, the better. However, it is desirable that the lower limit is 15 mN / m. This is because the surface tension is less than 15 mN / m, the amount of the surfactant added is increased, and the economic effect is poor.

  If the viscosity at 25 ° C exceeds 10 Pa · s, or if the surface tension exceeds 40 mN / m, the paint wettability becomes poor when a paint is applied, and a gap is formed in the gap with the metal plate. Under the corrosive environment (organic acid aqueous solution), the corrosive liquid penetrates into the voids, leading to peeling of the coating film. The lower the viscosity, the better, but it is more preferably 0.1 to 1 Pa · s in view of coating properties.

  The viscosity and surface tension can be measured by using, for example, a torque balance / servo system viscometer and a plate method (Wilhelmy method) automatic surface tension meter in a room at 25 ° C.

  The addition amount of the adhesiveness imparting agent in the fluororubber coating composition (A) needs to be 0.1% to 10%. When the addition amount is 0.1% or less, the adhesion to the metal plate is insufficient, and the coating film peels off in a corrosive environment. When the addition amount exceeds 10%, the barrier property of the coating film is lowered, and the permeability of the fuel containing the organic acid is increased, so that the corrosion resistance cannot be ensured.

  Furthermore, the film thickness after coating film formation of the fluororubber coating composition (A) needs to be 1 μm to 2000 μm. When the film thickness is less than 1 μm, coating film defects exist, and therefore corrosion progresses through the coating film defects. On the other hand, when the film thickness is 2000 μm or more, the stress at the time of curing the coating film concentrates on the interface with the coating film, so that the coating film is peeled off and the corrosion resistance is deteriorated. The film thickness after coating film formation of the fluororubber coating composition (A) is preferably 5 μm to 800 μm, and more preferably 15 μm to 400 μm.

Examples of the fluororubber in the fluororubber coating composition (A) include a copolymer having a molecular structure in which the main chain includes the following repeating units.
_{-CF 2 -CH 2 -, - CH} 2 -CH 2 - and _-CH 2 -CH (CH ₃₎ - at least one repeating unit selected from, _{and, -CF 2 -CF (CF 3)} -, _{-CF 2 -CF 2 -, - CF} 2 -CFCl -, - CF 2 -CF (CF 2 H) - and _CF 2 -CF (ORf) - wherein, Rf is selected from the group consisting fluoroalkyl having 1 to 9 carbon atoms It is a group. ] At least 1 type of repeating unit selected from these.

  Examples of the fluororubber include VdF-based fluorine-containing copolymers such as a copolymer of vinylidene difluoride [VdF] and hexafluoropropylene [HFP], a copolymer of VdF, tetrafluoroethylene [TFE], and HFP. , A copolymer of TFE and propylene, a copolymer of perfluoroalkyl vinyl ether [PFVE] and an alkene such as a copolymer of ethylene and HFP, and the like. Of these, a VdF-based fluorine-containing copolymer is preferable from the viewpoint of crosslinkability. Here, the VdF fluorine-containing copolymer is a fluorine-containing copolymer containing VdF as a monomer component.

  The molecular weight of the fluororubber is preferably 5,000 to 200,000. If the molecular weight is less than 5,000, the degree of vulcanization may be inferior, and if the molecular weight exceeds 200,000, the fluidity of the fluororubber coating composition (A) may be deteriorated and the coating workability may be inferior.

  The fluororubber is preferably a fluorine-containing copolymer that can exhibit elasticity. For example, a commercially available product can be used. For example, “DAIEL” (registered trademark, manufactured by Daikin Industries, Ltd.), “Viton” “From” (registered trademark, manufactured by EI DuPont), “Kalrez” (registered trademark, manufactured by EI DuPont), “Aphras” (registered trademark, manufactured by Asahi Glass), and the like. The fluororubber may also be synthesized by a conventionally known method such as emulsion polymerization. As said fluororubber, 1 type (s) or 2 or more types can be used.

  The fluororubber may be vulcanized and cured. The vulcanizing agent used for the vulcanization is not particularly limited, and for example, a commonly used fluororubber vulcanizing agent can be used. As the vulcanizing agent, the following are preferably used.

(1) Polyamine vulcanizing agent Triethylenetetramine, tetraethylenepentamine, ethylenediamine, triethylenediamine, ethanolamine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraoxa-2-spiro [5.5] Aliphatic polyamines and salts thereof such as undecane; aromatic amines and salts thereof such as diaminodiphenylmethane, xylylenediamine, phenylenediamine, diaminodiphenylsulfone, diaminodiphenyl ether; modified polyamines; polyamidoamines

(2) Polyol-based vulcanizing agent Examples of the compound and polymer compound having at least two hydroxyl groups, particularly phenolic hydroxyl groups in the molecule, having vulcanization performance may be mentioned. For example, phenol derivatives such as bisphenol A, bisphenol AF, and hydroquinone, and salts thereof; polyhydroxy compounds such as phenol resin having two or more enol-type hydroxyl groups in the molecule and salts thereof; and the following general formula Rf ′ (CH ₂ OH) ₂ [ However, Rf 'is a perfluoroalkyl polyether group. And the like.

(3) Polythiol-based vulcanizing agent Triazine thiol, 1,6-hexanedithiol, 4,4′-dimethylmercaptodiphenyl, 1,5-naphthalenedithiol and the like can be mentioned.

  As the vulcanizing agent, in addition to the above, any vulcanizing agent marketed as a vulcanizing agent for fluororubber can be used, and one or more can be used. As the vulcanizing agent, when the medium described later is an organic solvent, it is preferable to use a material soluble in the organic solvent, and when the medium is water, it is preferable to use a material soluble in water. .

  The vulcanizing agent is preferably 0.1 to 20 parts by mass with respect to 100 parts by mass of the fluororubber on the basis of solid content from the viewpoint of efficiently and sufficiently performing the vulcanization, and 0.5 to 15 parts. More preferably, it is part by mass.

  In order to accelerate the vulcanization, a vulcanization aid can be used for the fluororubber. Although it does not specifically limit as said vulcanization | cure adjuvant, For example, quaternary phosphonium salts, such as a triphenylphosphine benzyl chloride salt; Trimethylamine, triethylamine, tri n-propylamine, tri n-butylamine, triisobutylamine, methyldiethylamine, dimethyl Ethylamine, dimethyl n-propylamine, dimethyl n-butylamine, dimethylisobutylamine, dimethylisopropylamine, dimethyl-sec-butylamine, dimethyl-tert-butylamine, triallylamine, diallylmethylamine, allyldimethylamine, benzyldimethylamine, benzyldiethylamine N-allylpiperidine, N-ethylpiperidine, N-butylpiperidine, N-methylpyrrolidine, N-cyclohexylpyrrolidine, -n- butyl pyrrolidine, N- ethylpyrrolidine, N- benzyl pyrrolidine, tertiary amines such as 2,4,6-trimethylpyridine; compounds such as quaternary ammonium salts are preferred.

  Examples of the quaternary ammonium salt include trimethylbenzylammonium chloride, triethylbenzylammonium chloride, dimethyldecylbenzylammonium chloride, triethylbenzylammonium chloride, myristylbenzyldimethylammonium chloride, dodecyltrimethylammonium chloride, dimethyltetradecylbenzylammonium chloride, Trimethyltetradecylammonium chloride, stearyltrimethylammonium chloride, distearyldimethylammonium chloride, tetrabutylammonium hydroxide, 1,4-phenylenedimethylenebistrimethylammonium dichloride, 1,4-phenylenedimethylenebistriethylammonium dichlora And alkyl and aralkyl quaternary ammonium salts such as ethylenebistriethylammonium dibromide; 8-methyl-1,8-diaza-bicyclo [5.4.0] -7-undecenium chloride, 8-methyl-1 , 8-diaza-bicyclo [5.4.0] -7-undecenium iodide, 8-methyl-1,8-diaza-bicyclo [5.4.0] -7-undecenium hydroxide, 8 -Methyl-1,8-diaza-bicyclo [5.4.0] -7-undecenium-methyl sulfate, 8-methyl-1,8-diaza-bicyclo [5.4.0] -7-undecenium bromide , 8-propyl-1,8-diaza-bicyclo [5.4.0] -7-undecenium bromide, 8-dodecyl-1,8-diaza-bicyclo [5.4.0] 7-undecenium chloride, 8-dodecyl-1,8-diaza-bicyclo [5.4.0] -7-undecenium hydroxide, 8-eicosyl-1,8-diaza-bicyclo [5.4, 0] -7-undecenium chloride, 8-tetracosyl-1,8-diaza-bicyclo [5.4.0] -7-undecenium chloride, 8-benzyl-1,8-diaza-bicyclo [5. 4.0] -7-undecenium chloride, 8-benzyl-1,8-diaza-bicyclo [5.4.0] -7-undecenium hydroxide, 8-phenethyl-1,8-diaza-bicyclo Quaternary such as [5.4.0] -7-undecenium chloride, 8- (3-phenylpropyl) -1,8-diaza-picyclo [5.4.0] -7-undecenium chloride 1,8-diaza-bicyclo [5.4.0] -7-undecenium salt and the like.

  As the vulcanization aid, when the medium is an organic solvent, a solvent soluble in the organic solvent is preferably used. When the medium is water, a solvent soluble in water is preferably used. .

  The vulcanization aid is preferably from 0 to 10 parts by mass, more preferably from 0.1 to 8 parts by mass based on 100 parts by mass of the fluororubber, based on the solid content, from the viewpoint of efficiently and sufficiently performing the vulcanization. preferable.

  The adhesiveness imparting agent used in the fluororubber coating composition (A) is not particularly limited, and examples thereof include coupling agents such as a silane coupling agent, a titanium coupling agent, and an aluminum coupling agent. As the above-mentioned adhesion imparting agent, those having adhesiveness among the above vulcanizing agents can be used. For example, depending on the addition amount of aminosilane compound, polyamidoamine, phenol resin, etc. The thing etc. which can function are mentioned.

  The fluororubber coating composition (A) contains various additives usually added to a general fluororubber composition, for example, a filler, a colorant, an acid acceptor, etc., if necessary, in addition to the fluororubber. It may be a compounded one.

  The filler is not particularly limited, and examples thereof include carbon black, white carbon, calcium carbonate, barium sulfate, talc, and calcium silicate. The colorant is not particularly limited, and examples thereof include inorganic pigments and composite oxide pigments. The acid acceptor is not particularly limited, and examples thereof include double salts such as magnesium oxide, lead oxide, zinc oxide, lead carbonate, zinc carbonate, and hydrotalcite. The acid acceptor can usually be blended in an amount of 1 to 40 parts by mass based on the solid content based on 100 parts by mass of the fluororubber.

  The fluororubber coating composition (A) may further contain a medium. In the present specification, the medium is a substance that dissolves or disperses the components of the coating composition. The medium used in the fluororubber coating composition (A) is not particularly limited, and either an organic solvent or water may be used. The specified viscosity and surface tension can be controlled by selecting and adding these media.

  Examples of the organic solvent include ketones such as methyl ethyl ketone and methyl isobutyl ketone; esters such as butyl acetate and isopentyl acetate; ethers such as diethylene glycol dimethyl ether; hydrocarbons such as toluene and xylene; N, N-dimethylacetamide; Examples include amides such as N-methyl-2-pyrrolidone. The organic solvent is preferably used in an amount of 40 to 90% by mass based on the total mass of the fluororubber coating composition (A).

  When water is used as the medium, a dispersant is preferably used to disperse the fluororubber in the medium. Examples of the dispersant include anionic surfactants such as lauryl sulfate, perfluoroalkylcarboxylate, and ω-hydroperfluoroalkylcarboxylate; nonionic interfaces such as polyethylene glycol derivatives and polyethylene glycol / polypropylene glycol derivatives Activating agents; Alkyl polyethylene glycol ethers, alkyl phenyl polyethylene glycol ethers, alkyl polyethylene glycol esters, ethylene glycol / propylene glycol copolymers, polyethylene glycol alkyl esters, polycarboxylates and other resin dispersants. The dispersant is preferably used in an amount of 0.1 to 10% by mass based on the total mass of the fluororubber coating composition (A).

  When water is used as the medium, a drying retarder may be used. The drying retardant is not particularly limited, and examples thereof include water-soluble and high-boiling organic solvents, such as ethylene glycol, triethylene glycol, diethanolamine, triethanolamine, butyl carbitol, cellosolve, cellosolve acetate, and the like. Is mentioned. Further, when water is used as the medium, it is preferable to add a drying retardant.

  It is preferable to use 30 to 90% by mass of water as the medium based on the total mass of the fluororubber coating composition (A). As said medium, it is preferable to use water from points, such as surface smoothing of the coating film obtained and environmental protection, and it is more preferable that the said water is 70-100 mass% in the said medium.

  The fluororubber coating composition (A) may be one with a stabilizer added for the purpose of improving storage stability. It does not specifically limit as said stabilizer, For example, a C1-C12 organic acid etc. are mentioned, A C1-C9 organic acid is preferable. Organic acids having 9 or more carbon atoms tend to remain in the coating film. More preferably, the stabilizer is an organic acid having 1 to 4 carbon atoms. More preferable organic acids as the stabilizer include monocarboxylic acids such as formic acid, acetic acid and propionic acid; dicarboxylic acids such as oxalic acid, malonic acid and succinic acid.

Hereinafter, the fuel container metal plate used in the experiment will be described in detail.
Zinc-tin alloy-plated steel sheet “Ecocoat-S (QMT)” (hereinafter referred to as EC) manufactured by Nippon Steel Co., Ltd., electro-zinc nickel alloy-plated steel sheet “Zinclite (QM)” (hereinafter referred to as ZL) Electrogalvanized steel sheet “JINCOAT (QM)” (hereinafter referred to as EG) was prepared as an original plate. A plate thickness of 0.8 mm was used. The plating adhesion amount used in this experiment was 30 to 32 g / m ² of all kinds.

  After applying a paraffinic lubricating oil (Z3 manufactured by Idemitsu Kosan Co., Ltd.) to the steel sheet, a fuel container was obtained with a height of 43 mm by Erichsen processing with a punch diameter of φ75 mm-R3. Next, the prepared original plate was spray degreased with a 2% by mass, 50 ° C. aqueous solution of alkaline degreasing solution “FC-4336” manufactured by Nippon Parkerizing Co., Ltd., washed with water and dried. Thereafter, the coating composition shown in Table 1 was applied to the inner bottom of the container by spraying so as to have a prescribed cured coating thickness, and cured to obtain a target fuel container (temperature measured at physical temperature). The time is the set temperature keep time.)

  “Daiel” manufactured by Daikin Industries, Ltd. was used as the fluororubber, and triethylenetetramine was used as the vulcanizing agent. As the adhesion-imparting agent, 3-glycidoxypropylmethyldimethoxysilane was used. Further, methyl isobutyl ketone was appropriately added to control the surface tension, and the viscosity was controlled using toluene.

  In addition, in a present Example, a viscosity and surface tension are the torque balance servo system viscometer (TV-25 type viscometer by Toki Sangyo Co., Ltd.) in a room of 25 degreeC, and the plate method (Wilhelmy method). It was measured with an automatic surface tension meter (DY-700 manufactured by Kyowa Interface Science Co., Ltd.).

Hereinafter, the details of the evaluation method of the produced fuel container will be described.
(1) Paint adhesion 80 mL of an organic acid aqueous solution (100 ppm formic acid, 200 ppm acetic acid, 100 ppm NaCl) was placed in the sample and allowed to stand at 65 ° C. for 1000 hours. Thereafter, a 1 mm-wide grid was cut (100 squares), and a tape peeling test was performed. ◎ when the coating film does not peel at all, ◯ when the edge of the cut coating film is only missing, △ when the remaining coating area of the mass is 50% or more, and the residual coating area of the mass is 50 The case of less than% was evaluated as x.

(2) Fuel dissolution resistance 80 mL of commercially available regular gasoline was placed in the sample, and the lid was mechanically covered with a stainless steel plate through an O-ring, and this was left at 45 ° C. for 1000 hours. The coating film swelling state after standing was visually evaluated and evaluated. ◎ when the surface of the coating is unchanged compared to before immersion, ○ when the surface of the coating has a slight residue such as earthworm swelling, △ when the coating is slightly swollen, When the film surface had a grave swelling such as earthworm swelling, and the swelling of the coating film was observed violently, it was evaluated as x.

(3) Internal Corrosion Resistance Test 8 mL of an organic acid aqueous solution consisting of 100 ppm formic acid and 200 ppm acetic acid and 72 mL of commercially available regular gasoline were placed in a sample, and the lid was mechanically covered with a stainless steel plate, which was left at 65 ° C. for 2000 hours. The coating film swelling state after standing was visually evaluated and evaluated. When the surface of the coating is unchanged compared to before immersion, ◎, when the coating surface is slightly discolored, ◯ when the coating is slightly swollen, and when the coating is peeled off and plating The case where the steel is corroded was evaluated as x, and the case where the ground iron was corroded was evaluated as xx.

Table 2 shows the evaluation results of the manufactured fuel container.

As mentioned above, although preferred embodiment of this invention was described in detail, this invention is not limited to this example. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

Claims (1)

On the surface of the metal plate after pressing corresponding to the inner surface of the metal fuel container, the viscosity at 25 ° C. is 10 Pa · s or less, the surface tension is 40 mN / m or less, and the adhesion imparting agent is added to the entire coating composition. mass 0.1 to 10% seen containing, based on, and the fluorine-containing rubber paint containing 0.1 to 20 parts by mass of the fluororubber 100 parts by weight of vulcanizing agent on a solids basis, as a coating 1 μm to 2000 μm is formed. A method for manufacturing a metal fuel container.