JP2017150091A - Surface treatment liquid, production method of surface treatment aluminum plate using surface treatment liquid and surface treatment aluminum plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface treatment aluminum plate, surface treatment liquid capable of forming the surface treatment aluminum plate, and a production method, the aluminum plate being excellent in fabrication adhesion of an organic resin coating layer even when severe fabrication is performed as a can production material, and showing excellent anticorrosion and anti shock resistance (dent resistance).SOLUTION: The surface treatment liquid for surface treatment by chemical conversion treatment of the aluminum plate, contains a water dispersible polyester resin, a water dispersible particulate component, a fluorine ion, and a zirconium ion or a titanium ion. The particulate component is a crosslinked particle composed by crosslinking of a crosslink polymer comprising a single copolymer of a (meta)alkyl acrylate ester, or another copolymer with another polymerizable monomer which is co-polymerizable with a (meta)alkyl ester, or an inorganic silica particle. Less than 10000 ppm of the polyester resin and less than 5000 ppm of the zirconium ion or the titanium ion are contained.SELECTED DRAWING: None

Description

  The present invention relates to a surface treatment liquid, a method for producing a surface-treated aluminum plate using the surface treatment liquid, and a surface-treated aluminum plate. More specifically, the present invention has excellent adhesion to an organic resin layer to be coated, A surface-treated aluminum plate capable of exhibiting excellent corrosion resistance and impact resistance (dent resistance) while having sufficient processability as a can material, a method for producing the surface-treated aluminum plate, and the surface-treated aluminum plate can be formed. Related to a surface treatment solution.

  An organic resin-coated metal plate coated with a metal material such as aluminum with an organic resin layer has long been known as a can-making material, and this laminate is subjected to drawing processing or drawing / ironing processing to fill beverages, etc. It is well known to make a seamless can for this purpose, or press-mold it to make a can lid such as an easy open end.

In such an organic resin-coated metal plate, the surface of the aluminum substrate is made of an inorganic or organic surface treatment agent in order to ensure adhesion between the aluminum substrate and the organic resin layer to be coated and to further improve the corrosion resistance of the aluminum substrate. Is being processed. For example, immersion chromate treatment represented by phosphoric acid chromate treatment is performed.
Phosphoric acid chromate treatment is widely used as a surface treatment for aluminum substrates because it has excellent adhesion and corrosion resistance. Many of the chromate treatments currently used are of the type that does not leave hexavalent chromium in the final product, but the treatment liquid contains hexavalent chromium, which is a hazardous substance, and after disposal. In view of the possibility of elution of chromium into the soil environment, a non-chromium surface treatment not containing chromium is desired.

  In view of these demands, various non-chromium surface treatments for can manufacturing materials have been proposed. As a non-chromium surface treatment of a typical aluminum alloy metal plate, a surface treatment with a zirconium compound can be mentioned. For example, zirconium and / or titanium are used on the surface of an aluminum-containing metal material using an acidic treatment liquid containing zirconium and titanium or a compound thereof, phosphate and fluoride and having a pH of about 1.0 to 4.0. A method of forming a chemical conversion film (Patent Document 1) containing as a main component an oxide, or a method of forming an organic-inorganic composite film containing an organic compound containing phosphorus as a main component, a phosphorus compound, and a zirconium or titanium compound (patent) Reference 2) or by the applicant of the present invention, which can be applied to both aluminum plates and steel plates, and is a non-chromium treatment that can be used for containers, and is characterized by containing Zr, O, and F as main components and not containing phosphate ions. A surface-treated metal material has been proposed (Patent Document 3).

JP 52-131937 A JP-A-11-229156 JP-A-2005-97712

  However, the above-mentioned chemical conversion film cannot provide sufficient corrosion resistance and impact resistance (dent resistance) when an organic resin coating layer is formed and used as a precoat material in the production of a can body or a can lid. It was. In addition, the method of forming an organic-inorganic composite coating containing an organic compound mainly composed of carbon, a phosphorus compound, and a zirconium or titanium compound improves adhesion to some extent, but has sufficient corrosion resistance and impact resistance (dent resistance). It was not. Furthermore, the surface treatment material containing Zr, O, and F as a main component and containing no phosphate ions is excellent in adhesion to the organic resin coating layer and can exhibit excellent corrosion resistance, but is based on electrolytic treatment. Because of its energy cost, the surface-treated metal material has excellent adhesion, corrosion resistance, and impact resistance (dent resistance) of the organic resin coating layer, as well as economy and productivity. It is desired to provide.

From such a point of view, the present inventors have formed a surface-treated aluminum plate, wherein a chemical conversion film containing a polyester resin and a zirconium compound or a titanium compound is formed on at least one surface of the aluminum plate. (Japanese Patent Application No. 2012-82181 and Japanese Patent Application No. 2012-82182).
Such a surface-treated aluminum plate is excellent in adhesion to the organic resin coating layer, corrosion resistance and impact resistance, and can be subjected to surface treatment by chemical conversion treatment, so that it is excellent in economy and productivity.

  However, when forming a seamless can by subjecting the organic resin-coated surface-treated aluminum plate to severe processing such as squeezing and ironing, the organic resin coating layer is distorted by processing, so the resin between the surface treatment film There was a possibility that a difference in shrinkage ratio occurred, and peeling or the like occurred between the organic resin layer to be coated and the surface-treated aluminum plate. That is, after forming a can body by subjecting an organic resin-coated surface-treated aluminum plate to a drawing process such as drawing ironing or drawing redrawing, a heat treatment is performed to alleviate distortion of the organic resin layer to be coated. If the adhesion of the chemical conversion coating to the aluminum substrate or the strength of the chemical conversion coating itself is insufficient, peeling from the organic resin layer may occur during the heat treatment process, and necking or flanging performed after the heat treatment process cannot be performed. was there.

Accordingly, the object of the present invention is to have excellent corrosion resistance and impact resistance (dent resistance) as a can-making material, withstand heat treatment, and remarkably excellent adhesion to an organic resin coating layer applicable to flange processing. Another object is to provide a surface-treated aluminum plate and a method for producing the same.
Another object of the present invention is to provide a surface treatment liquid capable of forming the surface-treated aluminum plate.

  According to the present invention, a surface treatment liquid for surface treatment of an aluminum plate by chemical conversion treatment includes a water-dispersible polyester resin, a water-dispersible particulate component, fluorine ions, and zirconium ions or titanium ions. The particulate component is a crosslinkable polymer composed of a homopolymer of (meth) acrylic acid alkyl ester or a copolymer of another polymerizable monomer copolymerizable with (meth) alkyl ester. There is provided a surface treatment liquid characterized in that the polyester resin is contained in an amount of less than 10,000 ppm and the zirconium ion or titanium ion is contained in an amount of less than 5000 ppm.

According to the present invention, the chemical conversion coating is applied to the aluminum plate by immersion treatment or spray treatment for 2 to 20 seconds using the surface treatment liquid adjusted to pH 1.5 to 4.0 and temperature 35 to 70 ° C. A method for producing a surface-treated aluminum plate is provided.
In the method for producing a surface-treated aluminum plate of the present invention, it is preferable that the ratio C / M of the carbon content C and the zirconium or titanium content M in the chemical conversion coating is less than 40.

  According to the present invention, there is further provided a surface-treated aluminum plate having a chemical conversion treatment film formed using the surface treatment liquid, wherein the ratio C / M of carbon amount C and zirconium or titanium amount M in the chemical conversion treatment film. Is less than 40. A surface-treated aluminum plate is provided.

The surface-treated aluminum plate of the present invention has excellent corrosion resistance and adhesion to the organic resin coating layer, and the surface-treated aluminum plate obtained by coating the surface-treated aluminum plate with an organic resin is squeezed and ironed. Even when subjected to severe processing such as processing, it has excellent adhesion with the organic resin coating layer, especially in the heat treatment process and flange forming part where more severe processing is performed after drawing ironing, Peeling of the organic resin coating layer during heat treatment can be effectively prevented.
Furthermore, the organic resin-coated surface-treated aluminum plate of the present invention is excellent in moldability and productivity and economy.

By further blending polycarboxylic acid, aluminum ion, zirconium ion or titanium ion and polycarboxylic acid exist as a metal chelate complex, and this metal chelate complex also improves the adhesion between metal and organic matter. Combined with the improvement in adhesion due to the polyester resin and the particulate component, the corrosion resistance and the work adhesion can be remarkably improved.
Furthermore, even when a pre-coating material using a polyester film is used as the organic resin coating layer, it is not necessary to interpose a coating layer such as a primer between the surface treatment film and the polyester film, and is excellent in productivity and economy. .

It is a figure which shows an example of the cross-sectional structure of the organic resin coating surface treatment aluminum plate of this invention.

The surface-treated aluminum plate of the present invention is characterized in that a chemical conversion treatment film containing a polyester resin, a particulate component, a zirconium compound or a titanium compound is formed on at least one surface of the aluminum plate. .
Conventionally, an inorganic surface treatment film containing a zirconium compound or a titanium compound is known, but the chemical conversion treatment film in the surface-treated aluminum plate of the present invention includes a polyester resin and a particulate component in addition to these inorganic substances. As a result, it was found that the workability, corrosion resistance, and impact resistance were remarkably improved as compared with the conventional inorganic surface treatment film.
That is, the surface treatment film comprising a polyester resin, a particulate component, a zirconium compound or a titanium compound has a zirconium compound or a titanium compound located on the aluminum plate side, and the polyester resin is fixed to the substrate by the zirconium compound or the titanium compound. Since the polyester resin uniformly covers the surface of the chemical conversion film by heat treatment such as application of the resin coating layer, the adhesion with the organic resin coating layer is remarkably improved. Further, in the present invention, the chemical conversion treatment film contains a particulate component, and the fluidity of the chemical conversion treatment film is controlled by the particulate component by depositing the particulate component simultaneously with the precipitation of zirconium oxide or titanium oxide. In addition, the anchor effect can improve the adhesion with the organic resin coating layer, prevent peeling of the organic resin coating layer during the heat treatment after processing, and improve the dent resistance. It becomes possible.

  Such excellent effects of the present invention are also apparent from the results of Examples described later. That is, when neither the water-dispersible polyester resin nor the water-dispersible particulate component is contained in the surface treatment liquid (Comparative Examples 1 and 2), the corrosion resistance is not satisfied, and only the water-dispersible polyester resin is used. When the components of the film are formed (Comparative Example 3), or when formed only with water-dispersible polyester and polycarboxylic acid (Comparative Example 4), the corrosion resistance is good, but after squeezing and ironing processing The organic resin coating layer peels off during the heat treatment. On the other hand, in the surface-treated aluminum plate of the present invention, the results satisfying both excellent workability, adhesion, and corrosion resistance were obtained without such peeling of the organic resin coating layer (Example 1). ~ 15).

In the surface-treated aluminum plate of the present invention, the amount of carbon C (mg / m ² ) derived from the polyester resin and the particulate component in the chemical conversion coating, and the polycarboxylic acid blended as necessary, and the amount of zirconium or titanium M The ratio C / M of (mg / m ² ) is preferably in the range of 1 to 40, particularly in the range of 5 to 30.
In the surface-treated aluminum plate having C / M in the above range, zirconium ions or titanium ions are appropriately deposited during the surface treatment, and a good chemical conversion film is formed together with the polyester resin, the particulate component, and the polycarboxylic acid. The surface-treated aluminum plate having the above-described excellent corrosion resistance and work adhesion can be surely obtained, but if the C / M value is smaller than the above range, the corrosion resistance may be slightly inferior depending on the contents. If the value of C / M is larger than the above range, the time required for the surface treatment becomes longer and the productivity is inferior.
Moreover, it is preferable that the filling rate (particle filling rate) of the particulate component in the chemical conversion film defined by the formula described later is 40% by weight or less, particularly 3 to 20% by weight. When the particle filling rate is larger than the above range, the amount of the polyester resin is small, and it becomes difficult to form a good chemical conversion coating. When the particle filling rate is smaller than the above range, the amount of the particulate component There is little possibility that the effects obtained by blending the particulate component cannot be sufficiently obtained.
Further, the amount of the deposited film is not particularly limited, but the carbon amount C is preferably in the range of 5 mg / m ^{2 to} 1000 mg / m ² , particularly 50 mg / m ^{2 to} 500 mg / m ² , The amount M of zirconium or titanium is preferably in the range of 1 mg / m ^{2 to} 200 mg / m ² , particularly 2 mg / m ^{2 to} 100 mg / m ² . When the amount is less than the above range, the aluminum plate is not sufficiently coated and the corrosion resistance becomes inferior. On the other hand, when the amount is more than the above range, the effect of improving the performance according to the increase in the coating amount is obtained. It is inferior in productivity.

  The carbon atomic weight (C) and the atomic weight (M) of zirconium or titanium in the chemical conversion coating can be quantified with a commercially available fluorescent X-ray analyzer. In this case, a calibration curve indicating the relationship between the weight film thickness and the X-ray intensity is prepared in advance from a plurality of samples with known weight film thicknesses for carbon and zirconium or titanium, and the X-ray intensity measured using the sample. Is converted into a weight film thickness based on a calibration curve.

(Measurement conditions of X-ray fluorescence analyzer)
Equipment used: ZSX100e manufactured by Rigaku Corporation
Measurement conditions: Measurement object Zr-Kα ray, C-Kα ray
Measurement diameter 20mm
X-ray output 50kV-70mA
Measurement time 20 seconds (Zr), 100 seconds (C)

(Calculation method of organic / inorganic ratio)
Regarding the calculation of the organic / inorganic ratio represented by the ratio of the amount of carbon derived from the polyester resin, polycarboxylic acid and organic particulate component in the chemical conversion coating and the amount of zirconium or titanium derived from the zirconium compound or titanium compound. The film amount obtained by fluorescent X-ray analysis was obtained by calculating using the following formula.
Organic / inorganic ratio = C / M (-)
C: Carbon amount in the chemical conversion coating (mg / m ² )
M: amount of zirconium or titanium in the chemical conversion coating (mg / m ² )

(Calculation method of particle filling rate)
Moreover, regarding the filling rate of the particulate component, an image is obtained by a normal scanning electron microscope measuring device (Hitachi: S-4800), and the number of the particulate component per unit area is measured to obtain the particulate component. The volume is calculated, converted to weight, and then calculated by grading the total weight.
Particle filling rate = A / B × 100 (wt%)
A: Weight of the particulate component in the chemical conversion coating (mg / m ² )
B: Weight of all organic components of the chemical conversion coating (mg / m ² )

(Method for confirming metal ion chelate complex)
The metal ion chelate complex in the chemical conversion film of the surface-treated aluminum plate is confirmed by measuring with a Fourier transform infrared spectrophotometer or the like. By complexing with a metal ion, the carboxylic acid is converted to a carboxylate. In general, the characteristic absorption band of the carboxylic acid, 920～970Cm around ^-1, 1700～1710Cm around ^-1, it is known that a wavelength of around 2500～3200Cm ^-1, characteristic absorption band of the carboxylic acid salt, It is known that the wavelength is in the vicinity of 1480 to 1630 cm ⁻¹ . By confirming these peaks, the presence or absence of a metal ion chelate complex derived from polycarboxylic acid can be determined. For the measurement, the chemical conversion treatment film may be directly measured using a surface-treated aluminum plate or a metal can, or an extract from the chemical conversion treatment film or the like may be used.

(Measurement conditions of Fourier transform infrared spectrophotometer)
Equipment used: Digilab FTS7000series
Measurement method: single reflection method using germanium prism Measurement wavelength region: 4000 to 700 cm ⁻¹

The organic resin-coated surface-treated aluminum of the present invention is formed by forming an organic resin coating layer on the chemical conversion film of the surface-treated aluminum plate. In the present invention, the surface-treated aluminum plate and the organic resin are used. Since the adhesion of the coating layer is excellent, the organic resin coating layer can be formed directly on the chemical conversion film, that is, without applying a primer or the like.
FIG. 1 is a diagram showing a cross-sectional structure of an example of an organic resin-coated surface-treated aluminum plate of the present invention, and chemical conversion treatment films 3, 3 containing particulate components 5, 5,. The organic resin coatings 4 and 4 are formed directly on the chemical conversion coatings 3 and 3.

(Particulate component)
The particulate component used in the present invention is not particularly limited as long as an effect such as corrosion resistance is exhibited, but if it is an organic material, a crosslinkable polymer whose glass transition temperature is not measured under heating conditions of 300 ° C. or less. The particles are preferably composed of a homopolymer of (meth) acrylic acid alkyl ester, or an ester of a copolymer with other polymerizable monomer copolymerizable with (meth) acrylic acid alkyl ester. It is desirable to use crosslinked particles having bonds.
Examples of the (meth) acrylic acid alkyl ester include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and n-butyl (meth) acrylate. , Isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-amyl (meth) acrylate, isoamyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ( (Meth) acrylic acid decyl, (meth) acrylic acid lauryl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid benzyl, (meth) acrylic acid 2-phenoxyethyl, (meth) acrylic acid 3-phenylpropyl, etc. ) Acrylic acid ester; Hydroxyethyl (meth) acrylate, H (meth) acrylic acid And the like can be given; Rokishipuropiru, (meth) acrylic acid, glycidyl (meth) acrylate.

  Examples of other polymerizable monomers copolymerizable with (meth) acrylic acid alkyl ester include styrenes such as styrene, α-methylstyrene, paramethylstyrene, isopropenylstyrene, chlorostyrene; acrylonitrile, methacrylo Unsaturated nitriles such as nitrile, ethacrylonitrile and phenylacrylonitrile; (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid or their half ester compounds; vinyl toluene; epoxy group-containing monomers such as allyl glycidyl ether Etc.

The crosslinking agent may be any monomer having a plurality of polymerizable double bonds in the molecule, and is not limited thereto, but includes ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, and triethylene glycol diester. (Meth) acrylate, nonaethylene glycol di (meth) acrylate, decaethylene glycol di (meth) acrylate, tetradecaethylene glycol di (meth) acrylate, pentadecaethylene glycol di (meth) acrylate, 1,3-butylene glycol di (Meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycerin di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerysto Tetra (meth) acrylate, diethylene glycol phthalate di (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, caprolactone-modified hydroxypivalate ester neopentyl glycol diacrylate, multifunctional polyester acrylate, multifunctional urethane acrylate, etc. (Meth) acrylic acid ester-based polyfunctional monomers: aromatic vinyl-based polyfunctional monomers such as divinylbenzene and its derivatives, divinylnaphthalene and its derivatives.
Furthermore, as the polymerization initiator for the (meth) acrylic acid alkyl ester and the crosslinking agent, conventionally known ones can be used, but are not limited thereto, but are not limited to this, a hydrogen peroxide polymerization initiator, an organic or inorganic peroxide And polymerization initiators and azo polymerization initiators.

  The inorganic particulate component is not particularly limited, but is preferably composed of a silica compound. Examples of the shape and type of the silica particles include spherical silica, chain silica, aluminum modified silica, and the like. Specifically, as the spherical silica, SNOWTEX N, SNOWTEX UP (manufactured by Nissan Chemical Industries), Examples include colloidal silica such as LUDOX (manufactured by WR Grace) and fumed silica such as Aerosil (manufactured by Nippon Aerosil Co., Ltd.). As chain silica, Snowtex PS (manufactured by Nissan Chemical Industries, Ltd.) Examples of the silica gel such as Adelite AT-20A (Asahi Denka Kogyo Co., Ltd.) include aluminum silica.

In the present invention, in particular, crosslinked particles composed of a homopolymer of poly (meth) methyl acrylate, or crosslinked particles composed of a copolymer of methyl (meth) acrylate and (meth) acrylic acid, or inorganic silica compound particles. It can be preferably used.
Crosslinked particles and inorganic silica compound particles mainly composed of poly (meth) acrylate represented by polymethyl methacrylate are excellent in various properties such as mechanical strength, transparency, weather resistance, hygiene, As shown in the examples described later, delamination generated in the heat treatment step can be effectively suppressed.
The particulate component used in the present invention preferably has an average particle size in the range of 1 to 200 nm, particularly 5 to 80 nm. When the average particle size is smaller than the above range, the flow of the chemical conversion film cannot be effectively suppressed by the crosslinked particles, and the anchor effect cannot be sufficiently obtained. On the other hand, when the average particle size is larger than the above range, it becomes difficult to sufficiently fix the particulate component by the polyester resin, and in any case, sufficient work adhesion is obtained as compared with the case where it is in the above range. It may be difficult to improve

(Surface treatment liquid)
The surface treatment liquid used for the surface treatment of the surface-treated aluminum plate of the present invention includes a water-dispersible polyester resin, a water-dispersible particulate component, fluorine ions, zirconium ions or titanium ions, and if necessary, polycarboxylic acid. It consists of an aqueous solution characterized by containing.
That is, in the present invention, as described above, the polyester resin and the particulate component are present in the form of a dispersion in the surface treatment liquid, and this polyester resin dispersion is uniform together with the zirconium compound or titanium compound in the chemical conversion coating. In addition, the particulate component is present on the surface of the aluminum plate, and the particulate component suppresses the flow of the chemical conversion coating and improves the adhesion by the anchor effect. Furthermore, if necessary, by adding a polycarboxylic acid, the adhesion can be further improved by the presence of a carboxyl group, and the polycarboxylic acid forms a metal chelate complex with a zirconium ion or a titanium ion. It becomes possible to provide a chemical conversion film excellent in adhesion and corrosion resistance.
Furthermore, by containing polycarboxylic acid, precipitation of an excessive zirconium compound or titanium compound can be suppressed during the surface treatment.

  In the surface treatment liquid of the present invention, the water-dispersible polyester resin is 500 to 10,000 ppm, particularly 1000 to 3000 ppm, the water-dispersible particulate component is 100 to 3000 ppm, the polycarboxylic acid is 5-2000 ppm, particularly 100 to 1000 ppm. Zirconium ions or titanium ions are preferably contained in an amount of 5 to 5000 ppm, particularly 100 to 3000 ppm. Along with the conditions of the surface treatment described below and the like, each component in the surface treatment liquid is in the above range, so that the C / M value in the chemical conversion coating is in the above-described range, and an excellent chemical conversion coating can be formed. If the content of each component is less than the above range, satisfactory corrosion resistance and adhesion cannot be obtained, while if there are more components than the above range, the stability of the treatment liquid is inferior. In addition to this, further improvement in corrosion resistance and the like cannot be obtained, and the economy is also lowered.

Examples of the water-dispersible polyester resin used in the surface treatment liquid of the present invention include a polyester resin containing a hydrophilic group as a component. These components may be physically adsorbed on the surface of the polyester dispersion, but are particularly preferably copolymerized in the polyester resin skeleton.
The hydrophilic group is a hydroxyl group, an amino group, a carboxyl group, a sulfonic acid group, or a derivative or metal salt thereof, an ether, or the like, and can exist in a state dispersible in water by including these in the molecule. .
Specific examples of the component containing a hydrophilic group include hydroxyl group-containing polyether monomers such as polyethylene glycol, polypropylene glycol, glycerin and polyglycerin, 5-sulfoisophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, 5 Examples include (4-sulfophenoxy) metal salts of sulfonic acid-containing monomers such as isophthalic acid, ammonium salts, and the like.
Also, a vinyl monomer having a hydrophilic group may be graft-polymerized to a polyester resin. Examples of the vinyl monomer having a hydrophilic group include those containing a carboxyl group, a hydroxyl group, a sulfonic acid group, an amide group, etc. Examples of the group that can be changed into a group include an acid anhydride group, a glycidyl group, a chloro group, and the like.
In the present invention, as the water dispersible polyester resin, those having a sulfonic acid group as a hydrophilic group can be suitably used.
Further, the monomer component for forming the water-dispersible polyester resin in combination with the monomer containing the hydrophilic group is not particularly limited as long as it is a commonly used monomer. Examples thereof include aromatic polyvalent carboxylic acids such as acid, isophthalic acid, terephthalic acid and naphthalenedicarboxylic acid, and aliphatic polyvalent carboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, cyclohexanedicarboxylic acid, and dimer acid. Examples of the glycol component include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, butylene glycol, neopentyl glycol, 1,6-hexanediol, and the like.
Further, the glass transition temperature of these water-dispersible polyester resins is preferably -40 ° C to 140 ° C, more preferably 20 ° C to 120 ° C. The number average molecular weight of the water-dispersible polyester resin is preferably 1000 to 100,000, more preferably 3000 to 80,000.
In addition, it is preferable that the dispersed particle diameter of the polyester resin in the water dispersible polyester resin is in the range of 5 to 400 nm, particularly 5 to 200 nm, thereby forming a chemical conversion treatment film that is dense and excellent in the coverage of the aluminum substrate. Can do.

  The polycarboxylic acid used in the surface treatment solution of the present invention is a homopolymer or copolymer of a monomer having a carboxyl group such as polyacrylic acid, polymethacrylic acid, polymaleic acid, polyitaconic acid, acrylic acid-methacrylic acid copolymer, etc. In particular, polyacrylic acid and polymethacrylic acid can be preferably used.

Zirconium compounds or titanium compounds that can supply zirconium ions or titanium ions to the surface treatment liquid are not limited to these, but include hexafluorozirconic acid, hexafluorozirconium potassium (KZrF ₆ ), and hexafluorozirconium ammonium ((NH ₄ ) ₂ ZrF ₆ ), zirconium carbonate ammonium solution ((NH ₄ ) ₂ ZrO (CO ₃ ) ₂ ), zirconium oxynitrate ZrO (NO ₃ ) ₂ , zirconium oxyacetate (ZrO (CH ₃ COO) ₂ ), etc., or titanium fluoride Potassium fluoride (K ₂ TiF ₆ ), ammonium titanium fluoride ((NH ₄ ) ₂ TiF ₆ ), sodium titanium fluoride (Na ₂ TiF ₆ ), potassium titanium oxalate dihydrate (K ₂ TiO (C ₂ O ₄ ) ₂ · _{2H 2} O) Titanium (III) chloride solution (TiCl _3), titanium (IV) chloride solution can be mentioned (TiCl ₄₎ or the like.
In addition, in the surface treatment liquid of this invention, by containing a fluorine ion, aluminum melt | dissolves and a zirconium compound or a titanium compound can be precipitated appropriately. Therefore, in the case where a compound other than the compound capable of supplying fluorine ions is used, sodium fluoride (NaF), potassium fluoride (KF), ammonium fluoride (NH ₄ F) or the like can be used in combination as the fluorine compound. .

In the surface treatment liquid of the present invention, it is not particularly necessary to add a surfactant or an oxidizing agent for dispersing the polyester resin, and the water dispersion is carried out in water or an aqueous medium composed of water and a small amount of an organic solvent. Type polyester resin, water-dispersible particulate component, zirconium compound or titanium compound can be prepared by blending the polyester resin, particulate component and zirconium ion or titanium ion at the above-mentioned concentrations. .
When free fluorine ions are present in the surface treatment liquid, it is desirable that the free fluorine ions are in the range of 5 to 5000 ppm. When the fluorine ion concentration is lower than the above range, the fluorine ion etching effect cannot be obtained. On the other hand, when the fluorine ion concentration is higher than the above range, the deposition efficiency may be hindered.

(Surface treatment method)
The surface treatment method for an aluminum plate using the surface treatment liquid of the present invention comprises mixing the above-mentioned water-dispersible polyester resin, particulate component, zirconium compound or titanium compound, and, if necessary, a polycarboxylic acid in an aqueous medium, Is a surface treatment solution prepared so as to have an amount of 500 to 10,000 ppm, a particulate component of 100 to 3000 ppm, a polycarboxylic acid of 5 to 2000 ppm, and a zirconium ion or a titanium ion of 5 to 5000 ppm. It can process by a processing system or a roll coat system.
The pH of the surface treatment liquid is preferably in the range of 1.5 to 4.0, and is adjusted by adding nitric acid or ammonia as necessary. If the pH is lower than the above range, a sufficient film cannot be obtained. On the other hand, if the pH is higher than the above range, the stability of the treatment liquid becomes poor.
Further, the temperature of the surface treatment liquid is not particularly limited, but it is desirable that it is in the range of 35 to 70 ° C. in order to stably form a film.
Prior to the immersion in the surface treatment solution, the aluminum plate is subjected to pretreatments such as degreasing, water washing, and if necessary, etching treatment, water washing, further acid pickling, and water washing in a conventional manner. Next, after immersion or spray treatment in a surface treatment solution adjusted to the above pH and temperature range for 2 to 20 seconds, it is washed with water and dried to obtain a surface-treated aluminum plate on which a chemical conversion treatment film is formed. it can.
In addition, the aluminum plate can use all the aluminum plates conventionally used for can-made materials, and may be a pure aluminum plate other than an aluminum alloy plate, and the thickness is not limited to this, What is in the range of 100-500 micrometers can be used conveniently.
Further, depending on the surface treatment method, the aluminum of the substrate may be dissolved, and the chemical conversion film may contain an aluminum compound.

(Organic resin-coated surface-treated aluminum plate)
The organic resin-coated surface-treated aluminum plate of the present invention is formed by coating a layer made of an organic resin on the chemical conversion film of the surface-treated aluminum plate. Since the above-mentioned surface-treated aluminum plate is used, the organic resin It is excellent in the adhesion of the coating layer, particularly in the processing adhesion, and thus has excellent corrosion resistance and impact resistance.
In the organic resin-coated surface-treated aluminum plate of the present invention, the organic resin provided on the chemical conversion coating is not particularly limited, and examples thereof include a film made of a thermoplastic resin or a coating film made of a thermosetting or thermoplastic resin. Can do.

Examples of the thermoplastic resin capable of forming a film include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic ester copolymer, olefin resin film such as ionomer, or polyethylene terephthalate. Polyester film, polyamide film such as nylon 6, nylon 6,6, nylon 11, nylon 12, etc., polyvinyl chloride film, polyvinylidene chloride film, etc. can be mentioned. Unstretched or biaxially stretched of such a thermoplastic resin film It may be what you did.
Further, paints capable of forming a coating include modified epoxy paints such as phenol epoxy and amino-epoxy, vinyl chloride-vinyl acetate copolymer, saponified vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-anhydrous maleic anhydride. Examples include acid copolymers, epoxy-modified-, epoxy-amino-modified, epoxyphenol-modified-vinyl paints or modified vinyl paints, acrylic paints, synthetic rubber-based paints such as styrene-butadiene copolymers, and the like. It may be a combination of two or more.

Among these, a coating made of a polyester resin film is most preferably used as a can-making material.
Of course, homopolyethylene terephthalate can be used as the polyester resin, but it is desirable in terms of impact resistance and workability to lower the maximum crystallinity that the film can reach. For this purpose, ethylene terephthalate is contained in the polyester. It is preferable to introduce copolymer ester units other than the above. It is particularly preferable to use a copolymerized polyester resin mainly composed of ethylene terephthalate units and containing a small amount of other ester units.
In general, 70 mol% or more, particularly 75 mol% or more of the dibasic acid component in the copolyester is composed of a terephthalic acid component, and 70 mol% or more, particularly 75 mol% or more of the diol component is composed of ethylene glycol. It is preferable that 1 to 30 mol%, particularly 5 to 25 mol% of the component is composed of a dibasic acid component other than terephthalic acid.
Dibasic acids other than terephthalic acid include aromatic dicarboxylic acids such as isophthalic acid, phthalic acid and naphthalenedicarboxylic acid: alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid: succinic acid, adipic acid, sebacic acid, dodecanedioic acid, etc. Or a combination of two or more of the aliphatic dicarboxylic acids: As the diol component other than ethylene glycol or butylene glycol, propylene glycol, diethylene glycol, 1,6-hexylene glycol, cyclohexane dimethanol, bisphenol A 1 type, or 2 or more types, such as an ethylene oxide adduct.

In addition, the polyester resin may contain at least one branching or crosslinking component selected from the group consisting of trifunctional or higher polybasic acids and polyhydric alcohols in order to improve the melt flow characteristics during molding. it can. These branching or cross-linking components should be 3.0 mol% or less, preferably 0.05 to 3.0 mol%.
Examples of the trifunctional or higher polybasic acid and polyhydric alcohol include trimellitic acid, pyromellitic acid, hemimellitic acid, 1,1,2,2-ethanetetracarboxylic acid, 1,1,2-ethanetricarboxylic acid, 1 , 3,5-pentanetricarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic acid, polybasic acids such as biphenyl-3,4,3 ′, 4′-tetracarboxylic acid, pentaerythritol, glycerol, Examples include polyhydric alcohols such as trimethylolpropane, 1,2,6-hexanetriol, sorbitol, 1,1,4,4-tetrakis (hydroxymethyl) cyclohexane.

The homopolyester resin or copolymer polyester resin should have a molecular weight in the film forming range, and the intrinsic viscosity [η] measured using a phenol / tetrachloroethane mixed solvent as the solvent is 0.5 to 1.5, particularly It is good to be in the range of 0.6 to 1.5.
The polyester resin layer used for the organic resin coating of the present invention may be a single resin layer or a multilayer resin layer formed by coextrusion or the like. When a multilayer polyester resin layer is used, a polyester resin having a composition with excellent adhesiveness is selected for the base layer, that is, the surface-treated aluminum plate, and the surface layer has content resistance, that is, extraction resistance and non-adsorption of flavor components. This is advantageous because a polyester resin having an excellent composition can be selected.
In the polyester resin layer, known compounding agents for resins, for example, antiblocking agents such as amorphous silica, inorganic fillers, various antistatic agents, lubricants, antioxidants, ultraviolet absorbers, etc., according to known formulations Can be blended.
In the present invention, the thickness when the organic resin coating is a coating made of a thermoplastic resin such as a polyester resin is generally desirably in the range of 3 to 50 μm, and 0 when the organic resin coating is a coating film. The coating amount is desirably 5 to ²⁰ g / m ² . If the thickness of the organic resin coating is smaller than the above range, the corrosion resistance becomes insufficient. On the other hand, if the thickness is larger than the above range, a problem is likely to occur in terms of workability.

(Manufacture of organic resin-coated surface-treated aluminum plate)
In the present invention, the formation of the organic resin coating layer on the surface-treated aluminum plate can be performed by any means. For example, in the case of polyester resin coating, extrusion coating, cast film thermal bonding, biaxially stretched film heat In the case of coating with a thermosetting paint, it can be applied by a conventionally known method such as a roll coating method or a spray method.
In addition, as described above, in the present invention, since the adhesion of the organic resin coating of the surface-treated aluminum plate is excellent, the primer for adhesion between the chemical conversion treatment film and the organic resin coating, particularly a coating made of a polyester resin. It is not necessary to provide a coating film such as, but of course, it does not exclude the provision of a primer paint such as a conventionally known phenol epoxy paint excellent in adhesion and corrosion resistance. Or you may provide in any of polyester films beforehand.

(Can body)
As long as the can body of the present invention is formed from the aforementioned organic resin-coated surface-treated aluminum plate, it can be formed by any conventionally known can-making method, and can also be a three-piece can having a side seam. In general, a seamless can (two-piece can) is preferable. This seamless can is drawn and re-squeezed, bent and stretched by drawing and redrawing (stretching), and drawn and redrawn so that the organic resin-coated surface of the organic resin-coated surface-treated aluminum plate is at least the inside of the can. It is manufactured by attaching to a conventionally known means such as bending / stretching or ironing by drawing or drawing / ironing.

(Can lid)
The can lid of the present invention can be formed by any conventionally known lid-making method as long as it is formed from the above-mentioned organic resin-coated surface-treated aluminum plate, and is generally a stay-on-tab type easy open. It can be applied to a can lid or a full open type easy open can lid.

Example 1
An aluminum alloy plate (3104 material) was prepared, and degreased by being immersed in a 2% aqueous solution (50 ° C.) of a degreasing agent “Surf Cleaner EC371” (trade name) manufactured by Nippon Paint Co., Ltd. for 6 seconds. After degreasing, the substrate was washed with water and then immersed in a 2% aqueous solution (50 ° C.) of an etching agent “Surf Cleaner 420N-2” (trade name) manufactured by Nippon Paint Co., Ltd. for 6 seconds to perform an alkali etching treatment. After the etching treatment, the substrate was washed with water and then immersed in a 2% aqueous sulfuric acid solution (50 ° C.) for 6 seconds for acid cleaning.
After acid washing and water washing, a water-dispersed polyester resin (polyester “Vylonal MD2000” manufactured by Toyobo Co., Ltd., particle size 135 nm) as a main ingredient and crosslinked PMMA particles A (crosslinked polymethyl methacrylate particles: Nippon Shokubai Co., Ltd. “Eposta 050W” particle diameter 74 nm), polycarboxylic acid (polyacrylic acid “Jurimer 10LHP” manufactured by Toa Gosei Co., Ltd.) and zirconium compound (hexafluorozirconic acid manufactured by Aldrich Co.) as additives, 4000 ppm of polyester, It mix | blends so that a particulate component may be 1000 ppm, a polyacrylic acid may be 200 ppm, and a zirconium ion may be 500 ppm, nitric acid or ammonia is added as needed, pH is adjusted to 1.8, and an aluminum alloy board is then set for 10 seconds. By soaking A chemical conversion film was formed.

The prepared surface-treated aluminum plate was previously heated to a plate temperature of 250 ° C., and a polyethylene terephthalate film (film thickness: 16 μm) copolymerized with 15 mol% isophthalic acid was thermocompression bonded to both surfaces of the aluminum plate via a laminate roll. Thereafter, it was immediately cooled with water to obtain an organic resin-coated surface-treated aluminum plate.
After paraffin wax was electrostatically applied to both surfaces of the obtained organic resin-coated aluminum plate, it was punched out into a circle having a diameter of 156 mm to produce a shallow drawn cup. Next, this shallow drawn cup was subjected to redrawing-ironing processing and doming forming, followed by trimming of the opening edge portion to obtain a can body. Various characteristics of the can body were as follows.
Can body diameter: 66 mm
Can height: 168mm
Average thickness reduction rate of can side wall relative to original thickness: 60%

(Example 2)
Example 1 is the same as Example 1 except that the amount of the main polyester particles in the treatment liquid is 2300 ppm, the amount of the cross-linked PMMA particles A as the particulate component is 200 ppm, the amount of zirconium ions is 700 ppm, and the treatment time is 6 seconds. In the same manner, a surface-treated aluminum plate, an organic resin-coated surface-treated aluminum plate, and a can were obtained.

(Example 3)
In Example 2, the surface-treated aluminum plate and the organic resin coating were prepared in the same manner as in Example 2 except that the amount of the main polyester particles in the treatment liquid was 2000 ppm and the amount of the crosslinked component PMMA particles A as the particulate component was 500 ppm. A surface-treated aluminum plate and a can were obtained.

Example 4
In Example 2, the surface-treated aluminum plate and the organic resin coating were prepared in the same manner as in Example 2 except that the amount of the main polyester particles in the treatment liquid was 1500 ppm and the amount of the crosslinked PMMA particles A as the particulate component was 1000 ppm. A surface-treated aluminum plate and a can were obtained.

(Example 5)
In Example 2, the surface-treated aluminum plate and organic resin coating were prepared in the same manner as in Example 2 except that the amount of the main polyester particles in the treatment liquid was 1000 ppm and the amount of the crosslinked PMMA particles A as the particulate component was 1500 ppm. A surface-treated aluminum plate and a can were obtained.

(Example 6)
In Example 3, a surface-treated aluminum plate, an organic resin-coated surface-treated aluminum plate, and a can were obtained in the same manner as in Example 3 except that the amount of additive polyacrylic acid was 100 ppm.

(Example 7)
In Example 3, a surface-treated aluminum plate, an organic resin-coated surface-treated aluminum plate, and a can were obtained in the same manner as in Example 3 except that the amount of additive polyacrylic acid was 1000 ppm.

(Example 8)
In Example 7, a surface-treated aluminum plate, an organic resin-coated surface-treated aluminum plate, and a can were obtained in the same manner as in Example 7 except that the amount of zirconium ions was 4000 ppm.

Example 9
In Example 4, a surface-treated aluminum plate, an organic resin-coated surface-treated aluminum plate, and a can were obtained in the same manner as in Example 7 except that the amount of zirconium ions was 150 ppm.

(Example 10)
In Example 4, a surface-treated aluminum plate, an organic resin-coated surface-treated aluminum plate, and a can were obtained in the same manner as in Example 4 except that the amount of zirconium ions was 350 ppm.

(Example 11)
In Example 4, a surface-treated aluminum plate, an organic resin-coated surface-treated aluminum plate, and a can were obtained in the same manner as in Example 4 except that the amount of zirconium ions was 1400 ppm.

(Example 12)
In Example 4, the surface-treated aluminum plate was prepared in the same manner as in Example 4 except that the crosslinked PMMA particles A as the particulate component were changed to crosslinked PMMA particles B (Nippon Shokubai "Eposter 030W", particle size 40 nm). An organic resin-coated surface-treated aluminum plate and a can were obtained.

(Example 13)
In Example 4, the surface-treated aluminum plate was prepared in the same manner as in Example 4 except that the crosslinked PMMA particles A as the particulate component were changed to crosslinked PMMA particles C (“Epester 100W” manufactured by Nippon Shokubai Co., Ltd., particle size 155 nm). An organic resin-coated surface-treated aluminum plate and a can were obtained.

(Example 14)
In Example 1, the amount of polyester particles as the main agent is 5000 ppm, the crosslinked PMMA particles A as the particulate component are inorganic silica particles A (“LUDOX TMA” manufactured by WR Grace & Company, particle diameter 20 nm), and the treatment time is A surface-treated aluminum plate, an organic resin-coated surface-treated aluminum plate, and a can were obtained in the same manner as in Example 1 except that the time was 10 seconds.

(Example 15)
In Example 14, the inorganic silica particle A as the particulate component was changed to inorganic silica particle B (“LUDOX SM30” manufactured by WR Grace & Company, particle diameter: 7 nm), and the processing time was set to 10 seconds. In the same manner, a surface-treated aluminum plate, an organic resin-coated surface-treated aluminum plate, and a can were obtained.

(Comparative Example 1)
In Example 1, an organic resin-coated surface-treated aluminum plate and a can were obtained in the same manner as in Example 1 except that the chemical conversion treatment of the aluminum plate was phosphoric acid chromate treatment.

(Comparative Example 2)
In Example 1, except for the water-dispersible polyester resin, the particulate component, and the polycarboxylic acid, the surface-treated aluminum plate was treated in the same manner as in Example 1 except that the amount of zirconium ions was 1000 ppm and the treatment time was 6 seconds. An organic resin-coated surface-treated aluminum plate and a can were obtained.

(Comparative Example 3)
In Comparative Example 2, a surface-treated aluminum plate, an organic resin-coated surface-treated aluminum plate, and a can body in the same manner as in Comparative Example 2 except that the amount of water-dispersible polyester resin was 5000 ppm and the amount of zirconium ions was 250 ppm. Got.

(Comparative Example 4)
In Comparative Example 2, the surface-treated aluminum plate, the organic resin-coated surface-treated aluminum plate were treated in the same manner as in Comparative Example 2, except that the amount of the main component water-dispersible polyester resin was 2500 ppm and the amount of polyacrylic acid was 200 ppm. And a can body was obtained.

(Corrosion resistance test evaluation of metal cans)
The corrosion resistance test of the surface-treated aluminum plate was carried out after forming a can as described in the examples, followed by heat treatment at 210 ° C. for 180 seconds, filling and sealing an acidic model aqueous solution containing chloride ions, and taking a day or more. After dropping the can temperature to 5 ° C, with the metal can laid down, drop a 1kg metal lump vertically from a height of 4cm to a position 1cm from the bottom of the side wall of the can, and give an impact to dent. This was done by preparing and evaluating samples for evaluating impact resistance and corrosion resistance. When the corrosion resistance and dent resistance of the surface-treated aluminum plate are insufficient, the metal substrate dissolves at the exposed portion, and a metal compound is generated due to corrosion. Evaluation was performed by observing the area of white rust derived from these and confirming the corrosion area.
The model aqueous solution used for the test was adjusted to a pH of 3.0 by adding sodium chloride to 1000 ppm and adding citric acid thereto. A aging test for evaluating the corrosion resistance of the dent portion was conducted at a storage temperature of 37 ° C. for one month.
As a result, when the area of white rust in the dent part is equal to or less than that of the current phosphoric acid chromate-treated product (Comparative Example 1) at the time of 1 month, the corrosion resistance improving effect is recognized. In the case where there are many cases, the corrosion resistance improvement effect was not evaluated (“impossible”).

(Evaluation of adhesion of metal cans during heat treatment)
Adhesion evaluation at the time of heat treatment of the surface-treated aluminum plate was carried out by heating at 210 ° C. for 180 seconds using a laboratory oven after forming the can as described in the examples and before processing the necking and the flange portion. It was done by doing.
In this heat treatment, the case where the organic resin coating layer did not cause delamination from the end face of the mouth of the metal can was evaluated as “Yes”, and the case where the delamination occurred was evaluated as “No”.

The surface-treated aluminum plate of the present invention has excellent corrosion resistance and adhesion to the organic resin coating layer, and the organic resin-coated surface-treated aluminum plate formed by coating the surface-treated aluminum plate with the organic resin layer is harsh. Even when subjected to molding processing, it has excellent adhesion to the organic resin coating layer, can effectively prevent peeling of the organic resin coating during heat treatment, and cans that are molded by harsh molding processing, Alternatively, it can be effectively used for a can lid such as an easy open lid to which rivet processing or score processing is applied.
Moreover, since it is excellent also in corrosion resistance, it can be used suitably as a can-making material for can bodies or can lids used for highly corrosive contents.

  1: Organic resin-coated surface-treated aluminum plate, 2: Aluminum alloy material, 3: Chemical conversion coating, 4: Organic resin coating layer, 5: Particulate component

Claims (4)

  A surface treatment liquid for surface treatment of an aluminum plate by chemical conversion treatment, comprising a water-dispersible polyester resin, a water-dispersible particulate component, fluorine ions, and zirconium ions or titanium ions, the particulate component Is a crosslinked particle obtained by crosslinking a crosslinkable polymer comprising a homopolymer of (meth) acrylic acid alkyl ester or a copolymer of (meth) alkyl ester and another polymerizable monomer copolymerizable with Alternatively, the surface treatment liquid is characterized by being inorganic silica particles and containing the polyester resin in an amount of less than 10,000 ppm and the zirconium ion or titanium ion in an amount of less than 5000 ppm.   Using the surface treatment liquid according to claim 1 adjusted to pH 1.5 to 4.0 and temperature 35 to 70 ° C., a chemical conversion treatment film is formed on the aluminum plate by immersion treatment or spray treatment for 2 to 20 seconds. The manufacturing method of the surface treatment aluminum plate characterized by these.   3. The method for producing a surface-treated aluminum plate according to claim 2, wherein a ratio C / M of the carbon content C and the zirconium or titanium content M in the chemical conversion coating is less than 40. 4.   It is a surface treatment aluminum plate which has a chemical conversion treatment film formed using the surface treatment liquid of Claim 1, Comprising: Ratio C / M of carbon amount C and zirconium or titanium amount M in this chemical conversion treatment film is 40. The surface-treated aluminum plate characterized by being less than.

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