JP2017110288A - Organic resin coated seamless can - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic resin coated seamless can having excellent can production property, which provides a small load on the environment with less cost, and which has excellent in retort resistance suppressing surface defects such as exfoliation and blister of an organic resin coating layer in a flange part, even in a high temperature, high pressure, high humidity environment such as in retort sterilization.SOLUTION: In the organic resin coated seamless can having a surface process coating layer, and the organic resin coating layer on the surface process coating layer, on at least one face of a metal can, the surface process coating layer includes polycarboxylic acid polymer and zirconium compound, and a peak height ratio (β/α) of a maximum peak height (α) within frequency range 1660 to 1760 cmto a maximum peak height (β) within frequency range 1490 to 1659 cmis 0.10 to 2.40 when measuring an infrared absorption spectrum of the surface process coating layer.SELECTED DRAWING: None

Description

  The present invention relates to a surface-treated coating layer and an organic resin-coated seamless can having an organic resin coating layer on the surface-treated coating layer on at least one surface of a metal can. The present invention relates to an organic resin-coated seamless can having excellent retort resistance that can be applied to a retort sterilization treatment that is performed after filling.

  An organic resin-coated metal plate obtained by coating a metal plate such as aluminum with an organic resin has been known for a long time as a can-making material. It is also well known to make seamless cans for filling or making can lids such as easy open ends by press molding. For example, an organic resin-coated metal plate having a thermoplastic resin film made of a polyester resin mainly composed of ethylene terephthalate units as an organic resin coating layer is used as a can-making material for seamless cans (Patent Document 1).

  In addition, as a metal plate used for such an organic resin-coated metal plate for seamless cans, surface treatment such as chemical conversion treatment is generally performed for the purpose of securing corrosion resistance and adhesion with the organic resin coating layer. A surface-treated metal plate is used. As such surface treatment, for example, there is a phosphoric acid chromate treatment. It has been widely used because it has the suitability (retort resistance) for sterilization treatment such as retort treatment (pressure heat sterilization treatment) applied after filling and sealing the contents. There is an increasing demand for system surface treatment.

  Many non-chromium surface treatments for can materials have been proposed so far. For example, for organic resin-coated seamless aluminum cans, a chemical conversion treatment of an organic-inorganic composite system using a zirconium compound, a phosphorus compound, and a phenol compound has been proposed, and can exhibit excellent can-making ability and retort resistance. Yes (Patent Document 2). However, since the surface treatment proposed above is a chemical (reaction type) surface treatment that requires washing after the treatment, a large amount of waste water is generated, so that waste water treatment is costly and environmentally friendly. There is a concern that the load of

  On the other hand, unlike chemical molding surface treatments, non-chromium surface treatment by coating-type surface treatment (coating-type treatment) that requires no water washing after treatment, reduces the cost of wastewater treatment, and has a low environmental impact It has been proposed for industrial materials. For example, there has been proposed a resin-coated aluminum plate on which a coating-type undercoat comprising a zirconium compound and zirconium-crosslinked polyacrylic acid is formed (Patent Document 3).

JP 2001-246695 A JP 2007-76012 A JP 2007-176072 A

  However, the coating-type undercoat proposed in Patent Document 3 has been proposed particularly for resin-coated aluminum plates for cap molding, and was suitable for molding into caps with a small amount of processing. However, when it is applied to an organic resin-coated metal plate for a seamless can that is formed by a more severe forming process than that of a cap, there are the following problems. That is, when a seamless can is formed using the same, post-processing (necking processing and flange processing) of the can body was mainly performed during sterilization processing such as retort processing after filling and sealing the contents. In some cases, the organic resin coating layer may be peeled off due to insufficient adhesion between the organic resin coating layer and the metal substrate in a high temperature, high pressure, and high humidity environment. Furthermore, when the retort treatment is performed under more severe conditions such that the can body side wall portion on the outer surface side of the can is partially in contact with water and is pressurized and heated by steam, the can Due to insufficient adhesion between the organic resin coating layer and the metal base material in the vicinity of the portion of the can body side wall that is in contact with the water on the outer surface side, external surface defects such as floating or blistering of the organic resin coating layer may occur. It may occur. From the above points, it can be said that further improvement is necessary to apply to seamless cans.

  Therefore, the object of the present invention is to suppress the peeling of the organic resin coating layer in the flange portion even when subjected to high temperature, high pressure, and high humidity environments such as retort processing after filling and sealing the contents, Suppresses the occurrence of blisters and other external surface defects even when retort processing is performed under conditions where the outer surface of the can body is in contact with water and is heated under pressure with steam. Another object of the present invention is to provide an organic resin-coated seamless can having a surface-treated film layer formed by a non-chromium coating type treatment that has excellent retort resistance that can be produced, has a low environmental load, and is excellent in economy.

An organic resin-coated seamless can having a surface treatment film layer and an organic resin coating layer on the surface treatment film layer on at least one surface of a metal can, the surface treatment film layer comprising a polycarboxylic acid polymer and a zirconium compound And the maximum absorption peak height (α) in the wave number range of 1660 to 1760 cm ⁻¹ and the maximum in the wave number range of 1490 to 1659 cm ⁻¹ when the infrared absorption spectrum of the surface treatment film layer is measured. An organic resin-coated seamless can having a peak height ratio (β / α) to an absorption peak height (β) of 0.10 to 2.40 is provided.

In the organic resin-coated seamless can of the present invention,
1. The polycarboxylic acid polymer is a homopolymer or copolymer obtained by polymerization of at least one polymerizable monomer selected from acrylic acid, methacrylic acid, itaconic acid and maleic acid, or a polymer thereof. A mixture of coalescing,
2. The zirconium compound is a zirconium compound derived from an oxyzirconium salt;
3. The oxyzirconium salt is ammonium zirconium carbonate;
4). The content of the polycarboxylic acid polymer in the surface treatment film layer is ² to 100 mg / m ² in terms of carbon, and the content of the zirconium compound is 1 to 80 mg / m ² in terms of zirconium. ,
5). The surface treatment film layer contains a zirconium compound in an amount of 3 to 67 parts by mass in terms of zirconium with respect to 100 parts by mass of the solid content of the polycarboxylic acid polymer.
6). The surface treatment film layer further contains colloidal silica,
7). The colloidal silica content in the surface treatment film layer is 1 to 200 mg / m ² in terms of silicon,
8). The organic resin coating layer is a polyester resin film;
9. The seamless can is an aluminum seamless can;
Is preferred.

The present inventors have provided a surface treatment film layer containing a polycarboxylic acid polymer as a main component and a zirconium compound as a crosslinking component of the polycarboxylic acid polymer on at least one surface of the metal can, and the surface treatment film layer. In an organic resin-coated seamless can having an organic resin coating layer formed on the surface, a free carboxyl group (—COOH) of a polycarboxylic acid polymer not forming a metal salt with zirconium and a metal salt with zirconium are formed. Absorption in the wave number range of 1660 to 1760 cm ⁻¹ when measuring the infrared absorption spectrum of the surface treatment film layer, which is a measure of the quantitative ratio of carboxyl groups (—COO ⁻ ) of the polycarboxylic acid polymer. peak height (alpha) between the maximum absorption peak height in the wavenumber range of 1490~1659cm ^-1 (β) with the peak height ratio (beta / alpha) is, Yes A seamless can with excellent retort resistance that has a great impact on the retort resistance of resin-coated seamless cans, is excellent in can manufacturing ability, and can handle retort processing under the above-mentioned severe conditions. A suitable range for obtaining was found.
Thereby, it becomes possible to provide an organic resin-coated seamless can having excellent can-making suitability and retort resistance.
Moreover, since the surface-treated film layer of the present invention is formed by a non-chromium coating type treatment, there are advantages that it is excellent in economic efficiency and has a low environmental load.

The above-described operational effects of the present invention are also apparent from the results of the examples described later.
In an organic resin-coated seamless can having a surface-treated film layer containing a polycarboxylic acid-based polymer as a main component and a zirconium compound as a crosslinking component, 1660 to 1760 cm ⁻¹ when an infrared absorption spectrum of the surface-treated film layer is measured. The peak height ratio (β / α) between the maximum absorption peak height (α) in the wave number range of ¹ and the maximum absorption peak height (β) in the wave number range of 1490 to 1659 cm ⁻¹ exceeds 2.40. In the organic resin-coated seamless can having a surface treatment film layer of less than 0.10, peeling of the organic resin coating layer occurs at the flange portion in the flange portion peelability evaluation during retort, and the above-mentioned more severe conditions In the retort can barrel side wall appearance evaluation assuming retort processing in the above, occurrence of blisters is confirmed (Comparative Examples 1 to 3). On the other hand, in the organic resin-coated seamless can having the surface treatment film layer in which the peak height ratio (β / α) is in the range of 0.10 to 2.40, peeling of the organic resin coating layer and generation of blisters are caused. Obviously, it has excellent retort resistance in seamless cans. In addition, in organic resin-coated seamless cans having a surface treatment film layer with a peak height ratio (β / α) of less than 0.10, during heat treatment assuming a heat treatment step (heat setting step) performed after the can body part molding In flange part peelability evaluation (can manufacturing suitability evaluation), peeling of the organic resin coating layer occurs at the open end (flange forming part) of the can (Comparative Examples 1 and 2). On the other hand, in the organic resin-coated seamless can having the surface treatment film layer having a peak height ratio (β / α) in the range of 0.10 to 2.40, peeling of the organic resin coating layer is suppressed. It is clear that the can manufacturing ability is excellent. Furthermore, in addition to the polycarboxylic acid polymer and the zirconium compound described above in the surface treatment film layer, colloidal silica is further contained, thereby further improving the ability to make cans. In the flange part peelability evaluation at the time of heat treatment, as is clear from the comparison of the results of Examples 1 and 22 and 23, in the organic resin-coated seamless can having the surface treatment film layer containing colloidal silica, the flange at the open end It turns out that generation | occurrence | production of peeling of the organic resin coating layer in the formation part is further suppressed.

2 is an infrared absorption spectrum of a surface treatment film layer of an organic resin-coated seamless can obtained in Example 1. FIG. It is the figure which expands and shows the cross-sectional view of an example of the organic resin-coated seamless can of the present invention and the cross-sectional structure of the can body side wall.

(Surface treatment film layer)
The surface treatment film layer in the organic resin-coated seamless can of the present invention comprises a polycarboxylic acid polymer as at least a main component and a zirconium compound as a crosslinking component of the polycarboxylic acid polymer, and the surface treatment The maximum absorption peak height (α) in the wave number range of 1660 to 1760 cm ⁻¹ and the maximum absorption peak height (β) in the wave number range of 1490 to 1659 cm ⁻¹ when measuring the infrared absorption spectrum of the coating layer The peak height ratio (β / α) is in a certain range. This is due to the following reason.
In the surface treatment film layer, when the polycarboxylic acid polymer is crosslinked with a zirconium compound, the carboxyl group and zirconium contained in the polycarboxylic acid polymer react to form a metal salt of the carboxyl group and zirconium. The
In infrared absorption spectrum measurement, free carboxyl groups not forming a zirconium metal salt (-COOH), within the wavenumber range of 1660～1760Cm ^-1, the carboxyl group having an absorption maximum in the vicinity of 1720 cm ^-1 C = an absorption peak derived from O stretching vibration, while the carboxyl group forming the zirconium metal salt (-COO ^-) is the wave number range of 1490～1659Cm ^-1, an absorption maximum in the vicinity of 1560 cm ^-1 The absorption peak derived from the C = O stretching vibration of the metal salt of the carboxyl group having is shown. The absorbance of the surface treatment film layer is proportional to the amount of chemical species having infrared activity present in the surface treatment film layer. Therefore, the maximum absorption peak height in the wavenumber range of 1660~1760cm ^-1 (α) and the maximum absorption peak height in the wavenumber range of 1490~1659cm ^-1 (β) with the peak height ratio (beta / alpha) Of the carboxyl group contained in the polycarboxylic acid polymer is a free carboxyl group (—COOH) which does not form a metal salt with zirconium and a carboxyl group (—COO ⁻ ) which forms a metal salt with zirconium. This ratio is a measure for the quantity ratio. The larger the value, the smaller the abundance ratio of free carboxyl groups (—COOH), while the abundance ratio of carboxyl groups (—COO ⁻ ) forming metal salts with zirconium is high. It shows that it becomes.
In the surface treatment film layer in the present invention, the above-described peak height ratio (β / α) is 0.10 to 2.40, preferably 0.45 to 1.60, more preferably 0.58 to 1.45. Particularly preferably, it is desirable to be in the range of 0.78 to 1.45.

The effect in this invention is guessed as follows.
When the peak height ratio (β / α) is in the above range, free carboxyl groups (zirconium compounds and metal salts are present on the surface of the surface treatment film layer even under high temperature, high pressure, and high humidity environments such as retort treatment. The surface treatment coating layer and the organic resin coating layer are in good contact with each other through the free carboxyl group, and the polycarboxylic acid polymer is more appropriately added by the zirconium compound. By crosslinking, the heat resistance and water resistance of the polycarboxylic acid polymer are remarkably improved, and the cohesive failure of the surface treatment film layer is suppressed. As a result, the organic resin in the flange portion at the time of the above retort treatment The peeling of the coating layer and the occurrence of outer surface defects such as blisters on the side wall of the can body are suppressed, and excellent retort resistance is exhibited. In addition, even under high-temperature environments such as the heat setting process after can body part molding, the cross-linking improves the heat resistance of the polycarboxylic acid polymer and suppresses the cohesive failure of the surface treatment film layer, thereby reducing the organic resin. Peeling of the coating layer is suppressed, and excellent can-making ability can be expressed.
When the peak height ratio (β / α) is larger than the above range, free carboxyl groups on the surface of the surface treatment film layer contributing to adhesion with the organic resin coating layer are reduced, and the polycarboxylic acid heavy weight is reduced. When the coalescence is excessively cross-linked by zirconium, it becomes difficult for the surface treatment film layer to follow the metal base material in severe processing from the organic resin-coated surface-treated metal plate to the seamless can, Since the coverage of the surface treatment film layer is lowered, the adhesiveness between the surface treatment film layer and the organic resin coating layer is lowered due to these factors, and the retort resistance may be deteriorated. On the other hand, when the peak height ratio (β / α) is smaller than the above range, the surface treatment coating layer is likely to cohesively break during retort treatment due to insufficient heat resistance and water resistance of the polycarboxylic acid polymer. There is a possibility that the outer surface defects such as peeling of the organic resin coating layer in the flange part and blisters in the side wall part of the can body may occur, and the retort resistance may deteriorate, and in the heat setting process after the can body part molding The surface treatment film layer is likely to cohesively break due to insufficient heat resistance, which may cause the organic resin coating layer to peel off, which may deteriorate the ability to make cans.

Moreover, in this invention, content of the polycarboxylic acid type polymer of a surface treatment film layer is 2-100 mg / m < ² > in carbon conversion, Preferably it is 4-50 mg / m < ² >, More preferably, it is 6-40 mg / m < ² >. It is suitable that it is a range and content of a zirconium compound is 1-80 mg / m < ² > in conversion of a zirconium, Preferably it is 1-40 mg / m < ² >, More preferably, it is the range of 2-30 mg / m < ² >. More specifically, for the surface treatment film layer located at the bottom of the organic resin-coated seamless can, the content of the polycarboxylic acid polymer is 4 to 100 mg / m ² , preferably 11 to 50 mg / m in terms of carbon. m ² , more preferably in the range of 21 to 40 mg / m ² , and the zirconium compound content in terms of zirconium is ² to 80 mg / m ² , preferably ² to 40 mg / m ² , more preferably 4 to 30 mg. / M ² is preferable. On the other hand, for the surface treatment film layer on the side wall of the can body, the content of the polycarboxylic acid polymer is ² to 50 mg / m ² , preferably 4 to 25 mg / m ² , more preferably 6 to 20 mg in terms of carbon. that are contained in the range of / ^{m 2,} and 1 to 40 mg / ^{m 2} content of zirconium in terms of zirconium compound, preferably 1 to 20 mg / ^{m 2,} more preferably in the range of 2 to 15 mg / ^{m 2} Preferably it is. When there are more polycarboxylic acid-based polymer and zirconium compound than the above range, it is difficult to adjust to the above-mentioned peak height ratio (β / α) range, or the surface treatment film layer is more than necessary. This is uneconomical. On the other hand, when the content of the polycarboxylic acid-based polymer or the zirconium compound is less than the above range, it is difficult to adjust to the aforementioned peak height ratio (β / α) range, or There is a possibility that the surface treatment film layer becomes thinner than the required film thickness, and sufficient retort resistance cannot be obtained.

Further, when colloidal silica is further blended, the content of colloidal silica in the surface treatment film layer is 1 to 200 mg / m ² , preferably ^{2 to} 100 mg / m ² , more preferably 4 to 80 mg / m ^{2 in} terms of silicon. A range of m ² is preferred. More particularly, for the surface treatment film layer located in the can bottom portion of the organic resin-coated seamless can, content of colloidal silica, 2 to 200 mg / ^{m 2} of silicon in terms of, preferably 5 to 100 mg / ^{m 2,} more Preferably it is the range of 10-80 mg / m < ² >. On the other hand, for the surface treatment film layer located on the can barrel side wall, the colloidal silica content is 1 to 100 mg / m ² , preferably ² to 50 mg / m ² , more preferably 4 to 40 mg / m in terms of silicon. It is suitable to contain in the range of ² . By containing colloidal silica excellent in heat resistance in the surface treatment film layer within the above range, the heat treatment of the surface treatment film layer is further improved, and in the heat setting process after can body molding, the surface treatment film layer Cohesive failure is suppressed, peeling of the organic resin coating layer can be further suppressed, and suitability for canning is improved. When the content of colloidal silica is less than the above range, the above-mentioned effect cannot be expected. On the other hand, even if the amount of colloidal silica is larger than the above range, no further effect can be obtained, but rather retort resistance. May deteriorate.

As a composition of the surface treatment film layer in the organic resin-coated seamless can of the present invention, the zirconium compound is 3 to 67 parts by mass, preferably 18 in terms of zirconium with respect to 100 parts by mass of the solid content of the polycarboxylic acid polymer. It is suitable to contain at -52 mass parts, More preferably at 22-48 mass parts, Especially preferably at 29-48 mass parts. When there are more or less zirconium compounds than the above range, it may be difficult to adjust the peak height ratio to the above range, and the desired effect may not be obtained. Moreover, when colloidal silica is contained in the surface treatment film layer, colloidal silica is 10 to 200 parts by mass in terms of solid content (silicon dioxide; SiO ₂ ), particularly 100 parts by mass of the polycarboxylic acid polymer. It is suitable to contain in the quantity of 50-200 mass parts. If the amount of colloidal silica is less than the above range, sufficient heat resistance cannot be expected, while if the amount of colloidal silica is greater than the above range, no further improvement in heat resistance can be obtained. Retort resistance may deteriorate.

(Polycarboxylic acid polymer)
As the polycarboxylic acid-based polymer constituting the surface treatment film layer in the present invention, an existing polycarboxylic acid-based polymer can be used, and the polycarboxylic acid-based polymer refers to two or more in the molecule. A generic term for polymers having a carboxyl group. Examples of such polycarboxylic acid-based polymers include (co) polymers of ethylenically unsaturated carboxylic acids, copolymers of ethylenically unsaturated carboxylic acids and other ethylenically unsaturated monomers, Examples thereof include acidic polysaccharides having a carboxyl group in the molecule such as alginic acid, carboxymethyl cellulose, and pectin. These polycarboxylic acid polymers may be used alone or in combination of two or more.
Examples of such ethylenically unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Furthermore, examples of the ethylenically unsaturated monomer copolymerizable with these ethylenically unsaturated carboxylic acids include α-olefins such as ethylene and propylene, vinyl carboxylic acid esters such as vinyl acetate, alkyl acrylates, Examples include ethylenically unsaturated carboxylic acid esters such as alkyl methacrylate and alkyl itaconate, vinyl chloride, vinylidene chloride, styrene, acrylamides, acrylonitrile and the like. When the polycarboxylic acid polymer is a copolymer of ethylenically unsaturated carboxylic acid and carboxylic acid vinyl esters such as vinyl acetate, the carboxylic acid vinyl ester moiety is converted to vinyl alcohol by further saponification. Can be used.

Among such polycarboxylic acid polymers, from the viewpoint of retort resistance, the polycarboxylic acid polymer is at least one polymer selected from acrylic acid, methacrylic acid, itaconic acid, and maleic acid. A polymer containing a structural unit derived from a polymerizable monomer, or a mixture of the polymers is preferred. The polymer may be a homopolymer or a copolymer. In the polymer, a constituent unit derived from at least one polymerizable monomer selected from the acrylic acid, maleic acid, methacrylic acid, and itaconic acid is preferably 60 mol% or more, more preferably 80 mol%. Above, most preferably 100 mol%, that is, a polymer in which the polycarboxylic acid polymer is composed of at least one polymerizable monomer selected from acrylic acid, maleic acid, methacrylic acid, and itaconic acid. (However, the total structural unit is 100 mol%.) In the case where a structural unit other than the above structural units is included, the other structural units include, for example, the above-mentioned ethylenically unsaturated carboxylic acid and Examples thereof include copolymerizable ethylenically unsaturated monomers.
When the polycarboxylic acid-based polymer is a polymer composed of at least one polymerizable monomer selected from the acrylic acid, maleic acid, methacrylic acid, and itaconic acid, the polymerizable monomer A homopolymer, a copolymer, or a mixture thereof can be used. More preferably, polyacrylic acid, polymethacrylic acid, polyitaconic acid, polymaleic acid, and mixtures thereof can be used.

  The weight average molecular weight (Mw) of the polycarboxylic acid polymer is not particularly limited, but is 3,000 to 1,000,000, preferably 10,000 to 1,000,000, more preferably 10,000 to 500, It is desirable to be in the range of 000. When the weight average molecular weight is smaller than the above range, in a high temperature / high pressure / high humidity environment such as retort sterilization treatment or in a high temperature environment such as a heat setting process after can body molding, The surface treatment film layer may coagulate and break, and the retort resistance and can making ability may be inferior. On the other hand, when the weight average molecular weight is larger than the above range, the stability of the surface treatment liquid may be reduced, and the gel may be formed with time, which may cause difficulty in productivity.

(Zirconium compound)
Examples of the zirconium compound constituting the surface treatment film layer in the present invention include zirconium oxide, hexafluorozirconic acid (H ₂ ZrF ₆ ), hexafluorozirconium potassium (K ₂ ZrF ₆ ), and hexafluorozirconium ammonium ((NH ₄ ) ₂ ZrF ₆ ), ammonium zirconium carbonate ((NH ₄ ) ₂ ZrO (CO ₃ ) ₂ ), zirconium oxynitrate (ZrO (NO ₃ ) ₂ ), zirconium oxyacetate (ZrO (C ₂ H ₃ O ₂ ) ₂ ) , zirconium oxychloride (ZrOCl _2), oxy zirconium sulfate (ZrOSO _4), oxy zirconium carbonate (ZrOCO _3), oxy zirconium octylate _{(ZrO (C 8 H 15 O} 2) 2), hydroxide oxyzirconium (ZrO (OH _2), hydroxide zirconium oxychloride (ZrO (OH) Cl), potassium zirconium carbonate _{(K 2 (ZrO (CO 3} ) 2)), zirconium phosphate, zirconium lactate, zirconium acetylacetonate [Zr (OC (= CH _{2) CH 2 COCH 3) 4} ] , and the like. Among the above zirconium compounds, those not containing a fluorine component are preferable from the viewpoint of environmental load, and oxyzirconium salts are particularly preferable. Here, the “oxyzirconium salt” refers to a salt containing a positive divalent group (called zirconyl) represented by ZrO. Examples of the oxyzirconium salt include ammonium zirconium carbonate ((NH ₄ ) ₂ ZrO (CO ₃ ) ₂ ), zirconium oxynitrate (ZrO (NO ₃ ) ₂ ), and zirconium oxyacetate (ZrO (C ₂ H ₃ O ₂ ) ₂ ). , Zirconium oxychloride (ZrOCl ₂ ), zirconium oxysulfate (ZrOSO ₄ ), zirconium oxycarbonate (ZrOCO ₃ ), ammonium zirconium carbonate ((NH ₄ ) ₂ ZrO (CO ₃ ) ₂ ), oxyzirconium hydroxide (ZrO (OH) ₂ ), zirconium hydroxide oxychloride (ZrO (OH) Cl), potassium zirconium carbonate (K ₂ (ZrO (CO ₃ ) ₂ )) and the like, among which the water-soluble oxyzirconium salt is preferable, Viewpoint of stability and retort resistance in processing solutions Et al., Can be suitably used zirconium ammonium carbonate as a precursor.
When the above-mentioned water-soluble oxyzirconium salt (zirconium carbonate) is used as the zirconium compound, the oxyzirconium salt is oxidized with respect to 100 parts by mass of the polycarboxylic acid polymer in the surface treatment film layer. 5 to 90 parts by mass, preferably 25 to 70 parts by mass, more preferably 30 to 65 parts by mass, and particularly preferably 40 to 65 parts by mass in terms of zirconium (ZrO ₂ ). .

(Colloidal silica)
The colloidal silica constituting the surface treatment film layer in the present invention is not limited to this, but spherical such as LUDOX (manufactured by WR Grace), SNOWTEX N, and SNOWTEX UP (manufactured by Nissan Chemical Industries). Silica can be mentioned. The particle size of colloidal silica is desirably in the range of 2 to 80 nm, particularly 4 to 30 nm. Particles smaller than the above range are generally difficult to obtain. On the other hand, when the particle size is larger than the above range, it is difficult to uniformly distribute the colloidal silica in the surface treatment film layer, and the above-mentioned effects are difficult to obtain.

The surface-treated film layer in the present invention is a metal compound other than a zirconium compound (for example, a monovalent alkali metal compound such as sodium or potassium, or a polyvalent metal compound such as zinc, calcium, or aluminum, as long as the object of the present invention is not impaired. ) Can be used mixed or contained.
In addition, water-soluble polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinyl pyrrolidone, polyvinyl ethyl ether, polyacrylamide, acrylamide compounds, polyethyleneimine, starch, gum arabic, methylcellulose, etc., as long as the object of the present invention is not impaired. Polymers derived from aqueous dispersions (emulsions) such as polymers, polyvinyl acetate, ethylene / vinyl acetate copolymers, polyester resins, polyurethane resins and the like may also be included.

(Calculation of peak height ratio (β / α))
Here, a method for calculating the peak height ratio (β / α) of the surface treatment film layer of the organic resin-coated seamless can by the infrared absorption spectrum measurement described above will be described below. First, after cutting out the side wall of the can body as a measurement sample from the organic resin-coated seamless can and removing the organic resin coating layer by a predetermined method, the infrared absorption spectrum of the surface treatment film layer on the measurement sample surface is 4000 to 700 cm. ^After measuring the wave number range of ⁻¹ and subtracting the absorption peak derived from water vapor and carbon dioxide from the infrared absorption spectrum of the obtained surface treatment film layer, as illustrated in FIG. 1, 1660 to 1760 cm of the infrared absorption spectrum. to give maximum absorption peak height in the wavenumber range of ^-1 and (alpha) maximum absorption peak height in the wavenumber range of 1490～1659Cm ^-1 a (beta), the peak height ratio of using them (beta / α) is calculated. Here, the maximum absorption peak height (α) within the wave number range of 1660 to 1760 cm ⁻¹ and the maximum absorption peak height (β) within the wave number range of 1490 to 1659 cm ⁻¹ of the infrared absorption spectrum are defined as follows. To do.

Maximum peak height (alpha): the base within the wavenumber range of 1800～2000Cm ^-1, and that the absorbance is the lowest, in the wavenumber range of 1000 to 1200 ^-1, the straight line connecting the points at which the absorbance is the lowest A line is drawn perpendicularly to the horizontal axis (wave number) from the peak of the maximum absorption peak within the wave number range of 1660 to 1760 cm ⁻¹ , and the absorbance at the intersection of the line and the baseline and the absorbance at the peak of the maximum absorption peak Is the maximum peak height (α).
Maximum peak height (beta): base within the wavenumber range of 1800～2000Cm ^-1, and that the absorbance is the lowest, in the wavenumber range of 1000 to 1200 ^-1, the straight line connecting the points at which the absorbance is the lowest A line is drawn perpendicularly to the horizontal axis (wave number) from the peak of the maximum absorption peak in the wave number range of 1490 to 1659 cm ⁻¹ , and the absorbance at the intersection of the line and the baseline and the absorbance at the peak of the maximum absorption peak Let the difference be the maximum peak height (β).

The polycarboxylic acid polymer used in the present invention is a copolymer of ethylenically unsaturated carboxylic acid and other ethylenically unsaturated carboxylic acid esters such as alkyl acrylate or alkyl methacrylate, or ethylenically unsaturated carboxylic acid. A mixture of a polymer and an unsaturated carboxylic acid ester polymer, or a copolymer of an ethylenically unsaturated carboxylic acid and a carboxylic acid vinyl ester, or a mixture of an ethylenically unsaturated carboxylic acid polymer and a carboxylic acid vinyl ester polymer. In this case, the C═O stretching vibration attributed to the ester bond of the carboxylic acid ester (—COO—R: R is an alkyl group) has an absorption peak having an absorption maximum in the wave number range of 1730 cm ^{−1 to} 1760 cm ^−1. give. Therefore, strictly speaking, the maximum absorption peak in the wave number range of 1660 to 1760 cm ⁻¹ of the infrared absorption spectrum of the copolymer or mixture is derived from a carboxyl group (—COOH) and an ester bond (—COO—R). In this case, the peak height ratio (β / α) calculated by the above-described procedure is set to free carboxyl that does not form a metal salt with zirconium. It is used as it is as a scale representing the quantitative ratio of the group (—COOH), zirconium and the carboxyl group (—COO ⁻ ) forming the metal salt. Further, in the case where a compound having an ester bond or a polymer is contained in the surface treatment film layer as long as the object of the present invention is not impaired, the peak height ratio (β / α) is used as it is as a scale representing the quantitative ratio of the free carboxyl group (—COOH) that does not form a metal salt with zirconium and the carboxyl group (—COO ⁻ ) that forms a metal salt with zirconium.

On the other hand, when the surface treatment film layer contains a metal other than zirconium, such as an alkali metal such as sodium or potassium, or a polyvalent metal such as zinc or calcium, as long as the object of the present invention is not impaired (for example, When a metal salt other than zirconium of the polycarboxylic acid polymer is mixed or used as it is contained, etc.) C belonging to a metal salt (—COO ⁻ ) between a carboxyl group and a metal other than zirconium. = O stretching vibration gives an absorption peak having an absorption maximum in the vicinity of 1560 cm ^-1 within the wave number range of 1490 to 1659 cm ^-1 . Therefore, strictly speaking, at the peak of the infrared absorption spectrum, C═O stretching vibration derived from a metal salt of a carboxyl group and zirconium, and C═O stretching vibration partially derived from a metal salt of a carboxyl group and a metal other than zirconium. In this case as well, the peak height ratio (β / α) calculated by the above-described procedure is determined based on the free carboxyl group (—COOH), zirconium and metal salt not forming a metal salt with zirconium. It is used as it is as a scale representing the quantitative ratio of the carboxyl group (—COO ⁻ ) formed.

  In addition, as a method for measuring the infrared absorption spectrum of the surface-treated metal plate surface, a high-sensitivity reflection method (reflection absorption method) capable of measuring the infrared absorption spectrum of a thin film formed mainly on a metal substrate with high sensitivity. ) Is preferred. Furthermore, it is preferable to use a polarizer for the measurement. By detecting only parallel polarized light (P-polarized light) by using a polarizer, it is possible to measure with higher sensitivity. However, the use of a polarizer increases the noise because the amount of infrared light that can be used for the measurement is reduced, so a semiconductor-type cadmium telluride (MCT) detector is suitable as the detector used for the measurement. is there. Further, it is preferable to use a gold vapor deposition mirror as a reference substrate used for measurement.

(Surface treatment liquid)
The surface treatment liquid for forming the surface treatment film layer of the present invention can be formed from a surface treatment liquid containing a polycarboxylic acid polymer, a zirconium compound, an aqueous medium, and, if necessary, colloidal silica.
In such a surface treatment liquid, a zirconium compound is 3-67 mass parts in conversion of zirconium with respect to 100 mass parts of solid content of a polycarboxylic acid-type polymer, Preferably it is 18-52 mass parts, More preferably, it is 22 It is suitable to contain in -48 mass parts, Especially preferably in 29-48 mass parts. (In the case where the zirconium compound is the oxyzirconium salt described above, the oxyzirconium salt is 5 to 90 parts by mass, preferably 25 to 70 parts by mass in terms of zirconium oxide (ZrO ₂ ) per 100 parts by mass of the polycarboxylic acid polymer. Parts, more preferably 30 to 65 parts by mass, particularly preferably 40 to 65 parts by mass.)
Also when formulating the colloidal silica in the surface treatment liquid, the polycarboxylic acid polymer per 100 parts by weight of colloidal silica solids (silicon dioxide; SiO ₂₎ 10 to 200 parts by mass in terms of, in particular 50 to 200 mass It is preferable to blend in the amount of parts. If the amount of colloidal silica is less than the above range, sufficient heat resistance cannot be expected, while if the amount of colloidal silica is greater than the above range, no further improvement in heat resistance can be obtained. Retort resistance may be reduced.

  As said aqueous medium, water, such as distilled water, ion-exchange water, and pure water, can be used, and it contains organic solvents, such as alcohol, a polyhydric alcohol, its derivative (s) like a well-known aqueous composition. Can do. When using such a co-solvent, it can contain in the quantity of 5 to 30 weight% with respect to water. By containing the solvent in the above range, the film forming performance is improved. Examples of such organic solvents include methyl alcohol, ethyl alcohol, isopropyl alcohol, propylene glycol monopropyl ether, ethylene glycol monoble ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol mono Examples include butyl ether, tripropylene glycol monomethyl ether, and 3-methyl 3-methoxybutanol.

  The surface treatment liquid may further contain additives such as a stabilizer, an antioxidant, a surface conditioner, and an antifoaming agent that are used in general metal surface treatment liquids, if necessary.

(Method for forming surface treatment film layer on metal plate)
The method for forming the surface treatment film layer on the metal plate is not particularly limited. For example, the surface of the metal plate is subjected to degreasing treatment for removing rolling oil, rust preventive oil, etc. Then, the surface treatment liquid layer can be formed by applying the above-mentioned surface treatment liquid onto the metal plate and heating and drying.

  It does not specifically limit as said degreasing process, For example, the alkali washing | cleaning and acid washing which were conventionally used for the degreasing process of metal plates, such as aluminum and aluminum alloy, can be mentioned. In the present invention, from the viewpoint of adhesion between the surface-treated film layer and the metal substrate, a method of further performing acid cleaning after alkali cleaning, or a method of performing acid cleaning without performing the alkali cleaning is preferable. . In the degreasing treatment, the alkali cleaning is usually performed using an alkaline cleaner, and the acid cleaning is performed using an acidic cleaner.

  It does not specifically limit as said alkaline cleaner, For example, what is used for normal alkali washing | cleaning can be used, for example, "Surf cleaner 420N-2" by Nippon Paint, etc. are mentioned. It does not specifically limit as said acidic cleaner, For example, aqueous solution, such as inorganic acids, such as a sulfuric acid, nitric acid, and hydrochloric acid, is mentioned. After performing the above degreasing treatment, in order to remove the degreasing agent remaining on the surface of the metal plate, after performing a water washing treatment, water on the surface of the metal plate is removed by a method such as air blowing or hot air drying. .

  Surface treatment liquid is roll coat method, spray method, dipping method, brush coating method, spray squeezing method (After spraying the surface treatment liquid on the metal plate by spraying, the liquid film is squeezed with roll or air and dried) , After the surface treatment, the metal plate can be applied and treated by a conventionally known method such as immersion drawing (after immersing the metal plate in the surface treatment liquid and then strongly squeezing and drying the liquid film with a roll or air). The drying conditions are 50 to 300 ° C. and 5 seconds to 5 minutes, and particularly preferably 50 to 250 ° C. and 10 seconds to 2 minutes.

(Metal plate)
Although it does not specifically limit as a metal plate used for this invention, Various steel plates, an aluminum plate, etc. are used. As the steel plate, a cold-rolled steel plate annealed and then cold-rolled secondary can be used, and a clad steel plate or the like can also be used. As the aluminum plate, an aluminum plate made of an aluminum alloy in addition to so-called pure aluminum can be used. In the present invention, an aluminum plate made of an aluminum alloy can be particularly preferably used.
The original thickness of the metal plate is not particularly limited and varies depending on the type of metal and the use or size of the container, but the metal plate generally has a thickness of 0.10 to 0.50 mm. In the case of, the thickness is preferably 0.10 to 0.30 mm, and in the case of an aluminum plate, the thickness is preferably 0.15 to 0.40 mm.

In the present invention, a metal plate that has been previously subjected to a surface treatment such as chemical conversion treatment or plating may be used.
As the above-mentioned surface treatment, when using a steel plate as a metal plate, zinc plating, tin plating, nickel plating, aluminum plating, electrolytic chromic acid treatment, chromic acid treatment, phosphoric acid treatment, non-chromium using aluminum or zirconium What performed 1 type or 2 types or more of surface treatments, such as a process, can be mentioned. When an aluminum plate is used as the metal plate, an acrylic resin or a phenol resin is used for the inorganic chemical conversion treatment such as phosphoric acid chromate treatment, zirconium phosphate treatment, zirconium treatment, phosphoric acid treatment, and the inorganic chemical treatment. An organic-inorganic composite molding process in which organic components such as water-soluble resins and tannic acid are combined.

(Organic resin coating layer)
In the organic resin-coated seamless can of the present invention, the organic resin constituting the organic resin coating layer applied on the surface treatment film layer is not particularly limited. For example, crystalline polypropylene, crystalline propylene-ethylene copolymer , Crystalline polybutene-1, crystalline poly4-methylpentene-1, low-, medium- or high-density polyethylene, ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA) Polyolefins such as ion-crosslinked olefin copolymers (ionomers); aromatic vinyl copolymers such as polystyrene and styrene-butadiene copolymers; vinyl halide polymers such as polyvinyl chloride and vinylidene chloride resins; acrylonitrile-styrene Nitrile heavy polymers such as copolymers, acrylonitrile-styrene-butadiene copolymers Body: Polyamides such as nylon 6, nylon 66, para or metaxylylene adipamide; Polyesters such as polyethylene terephthalate (PET) and polytetramethylene terephthalate; Various polycarbonates; Thermoplastics such as polyacetals such as polyoxymethylene Resin is mentioned, The thermoplastic resin film comprised from these thermoplastic resins can be used as an organic resin coating layer.
As the organic resin coating layer used in the present invention, a thermoplastic resin film composed of a thermoplastic resin is suitable, and in particular, a polyester resin film can be suitably used.

The polyester resin constituting the polyester resin film may be a homopolyethylene terephthalate resin, an acid component other than terephthalic acid in an amount of 30 mol% or less based on the acid component, and an alcohol component other than ethylene glycol. It may be a copolymerized polyester resin composed mainly of polyethylene terephthalate containing 30 mol% or less based on the alcohol component, or a blend resin of a homopolyethylene terephthalate resin and a copolymerized polyester resin composed mainly of the polyethylene terephthalate.
Examples of the acid component other than terephthalic acid include isophthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, P-β-oxyethoxybenzoic acid, diphenoxyethane-4,4′-dicarboxylic acid, 5-sodium sulfoisophthalic acid, hexa Examples include hydroterephthalic acid, succinic acid, adipic acid, sebacic acid, dodecanedioic acid, dimer acid, trimellitic acid, and pyromellitic acid.
Examples of alcohol components other than ethylene glycol include propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexylene glycol, diethylene glycol, triethylene glycol, cyclohexanedimethanol, and ethylene oxide adduct of bisphenol A, Examples include glycol components such as trimethylolpropane and pentaerythritol.

  Further, a homopolyethylene terephthalate resin and / or a copolymerized polyester resin mainly composed of polyethylene terephthalate and crystalline polyester resins other than these, for example, a homopolybutylene terephthalate resin and / or a copolymerized polyester resin mainly composed of a polybutylene terephthalate resin, Alternatively, it may be a resin blended with a homopolyethylene naphthalate resin and / or a copolymer polyester resin mainly composed of a polyethylene naphthalate resin. In that case, the crystalline polyester resin other than the homopolyethylene terephthalate resin and / or the copolyester resin mainly composed of the polyethylene terephthalate resin with respect to the copolyester resin mainly composed of the homopolyethylene terephthalate resin and / or the polyethylene terephthalate resin. It is preferable that the compounding quantity of 5-50 wt%.

  Among the above polyester resins, in particular, a polyethylene terephthalate resin comprising an ethylene terephthalate unit, a polyethylene terephthalate / polyethylene isophthalate copolymer resin, a polyethylene terephthalate / polybutylene terephthalate copolymer resin, a polyethylene terephthalate / polyethylene naphthalate copolymer resin, a polyethylene terephthalate resin, and It is preferably one of a blend resin of polybutylene terephthalate resin, a blend resin of polyethylene terephthalate / polyethylene isophthalate copolymer resin and polybutylene terephthalate resin, particularly polyethylene terephthalate / polyethylene isophthalate copolymer resin, polyethylene terephthalate / polyethylene Isophthalate copolymer resin and polybutylene Blend resin of phthalate resin is preferable. The polyethylene terephthalate / polyethylene isophthalate copolymer resin preferably has an isophthalic acid content of 20 mol% or less (acid component basis). The blend resin of the polyethylene terephthalate / polyethylene isophthalate copolymer resin and the polybutylene terephthalate resin is a blend of polybutylene terephthalate resin in a range of 10 to 50 wt% with respect to the polyethylene terephthalate / polyethylene isophthalate copolymer resin. preferable.

  The polyester resin used as the organic resin coating layer should have a molecular weight in the range of film formation, and the intrinsic viscosity [η] measured using a phenol / tetrachloroethane mixed solvent as the solvent is 0.5 or more, especially 0.8. The range of 52 to 0.70 is preferable from the viewpoint of barrier properties against mechanical components and mechanical properties, and the glass transition point is preferably 50 ° C. or higher, particularly 60 ° C. to 80 ° C.

In a thermoplastic resin film such as a polyester resin film, per se known film compounding agents, lubricants, antiblocking agents, pigments, various antistatic agents, antioxidants, and the like can be blended according to known formulations.
In general, the thickness of a thermoplastic resin film such as a polyester resin film is preferably in the range of 5 to 40 μm.
The organic resin coating layer made of a thermoplastic resin film can be made into a two-layer structure. When a polyester resin is used as the thermoplastic resin, the lower layer is mainly composed of ethylene terephthalate units, such as isophthalic acid and naphthalenedicarboxylic acid. From the viewpoint of work adhesion, corrosion resistance, and the like, it is formed from a polyester resin containing at least one kind in an amount of 1 to 30 mol% and more in amount than the amount of the acid component in the upper polyester resin. Particularly preferred.

  The organic resin coating layer made of a thermoplastic resin film is formed on the surface treatment film layer through a conventionally known adhesive primer layer such as an epoxy / phenol resin system or a polyester / phenol resin system. Also good. The adhesion primer layer exhibits excellent adhesion to both the surface treatment film layer and the organic resin coating layer. The epoxy / phenolic resin-based adhesive primer may be formed from a paint containing epoxy resin and phenolic resin in a weight ratio of 50:50 to 99: 1, particularly 60:40 to 95: 5. From the viewpoint of adhesion and corrosion resistance. The polyester / phenolic resin-based adhesion primer may be formed from a paint containing polyester resin and phenolic resin in a weight ratio of 50:50 to 99: 1, particularly 60:40 to 95: 5. From the viewpoint of adhesion and corrosion resistance. In general, the adhesive primer layer is preferably 0.1 to 10 μm thick. The adhesion primer layer may be provided in advance on the surface treatment film layer on the surface treatment metal plate, or may be provided on the organic resin coating layer such as the polyester resin film.

(Method for forming organic resin coating layer on surface-treated metal plate)
As a method for forming the organic resin coating layer on the surface-treated metal plate, when the organic resin coating layer is a thermoplastic resin film, for example, after forming the thermoplastic resin film in advance by a conventionally known method, A method of coating on the treated metal plate by a thermal bonding method, an extrusion laminating method in which a heat-melted thermoplastic resin is extruded into a film using an extruder and directly coated on the surface-treated metal plate are suitable. When the thermoplastic resin film is formed and then coated, the film may be stretched, but an unstretched film is preferable from the viewpoint of molding processability and dent resistance.

(Can body and its manufacturing method)
The organic resin-coated seamless can of the present invention can be made from an organic resin-coated surface-treated metal plate by a conventionally known molding method.
The organic resin-coated surface-treated metal plate used in the present invention has a drawing process, drawing / deep drawing process, drawing / ironing process, drawing / bending and extending process because the organic resin coating layer has excellent processing adhesion. -Seamless cans formed by severe processing such as ironing can be formed without causing peeling of the resin coating on the broken body or flange forming portion.
The side wall portion of the seamless can is 20 to 95%, especially 25 to 85% of the original thickness of the organic resin-coated surface-treated metal plate by bending and stretching by drawing-redrawing or further ironing of the organic resin-coated surface-treated metal plate. It is preferable that the thickness is reduced so that the thickness becomes.
The obtained seamless can is subjected to at least one stage of heat treatment, the residual distortion of the film generated by the processing is removed, the lubricant used in the processing is volatilized from the surface, and the printing ink printed on the surface is dried and cured. The container after the heat treatment is rapidly cooled or allowed to cool, and then subjected to a one-stage or multi-stage neck-in process if necessary, and a flange process is performed to obtain a can for winding.

  FIG. 2 is an enlarged cross-sectional view of an example of the organic resin-coated seamless can of the present invention and the cross-sectional structure of the can body. This organic resin-coated seamless can 10 is applied to both surfaces of the metal substrate 2. The surface treatment coating layers 3a and 3b and the organic resin coating layers 4a and 4b are made of an organic resin-coated surface-treated metal substrate 1. In the specific example shown in FIG. 2, the organic resin coating layers 4a and 4b are formed on both the inner and outer surfaces of the metal substrate 2 via the surface treatment coating layers 3a and 3b. In the seamless can, the surface treatment film layer 3 and the organic resin coating layer 4 may be formed on at least one side of the can body, and different surface treatment film layers and organic resin coatings may be formed on the inner surface or the outer surface of the can body. Layers can also be formed.

  EXAMPLES Hereinafter, although a specific Example is given and this invention is demonstrated in detail, this invention is not limited by a following example. In the following description, “part” means “part by mass”.

[Examples 1 to 24, Comparative Examples 1 to 3]
(Preparation of surface treatment solution)
The polycarboxylic acid polymer was dissolved in ion-exchanged water to obtain a 2% by mass polycarboxylic acid polymer aqueous solution. An aqueous solution of a zirconium compound was gradually added to the obtained polycarboxylic acid polymer aqueous solution with stirring at room temperature so as to obtain a predetermined solid content blending ratio. In addition, the aqueous solution of the zirconium compound was adjusted to a predetermined solid content concentration with ion-exchanged water as necessary, and then added to the polycarboxylic acid polymer aqueous solution. Furthermore, when colloidal silica is blended, an aqueous dispersion of colloidal silica is added to an aqueous solution containing a polycarboxylic acid polymer and a zirconium compound while stirring at room temperature so as to obtain a predetermined solid content blending ratio. did. Next, ion-exchanged water was added while stirring, and the solid content concentration of the polycarboxylic acid polymer in the aqueous solution was adjusted to 0.5 to 1% by mass to obtain a surface treatment liquid.

Examples of the polycarboxylic acid-based polymer include polyacrylic acid (“Julimer AC-10LP, Mw = 25,000” manufactured by Toagosei Co., Ltd .: “PAA1” in the table, “Julimer 10LHP, Mw = 250,000”: Table Notated as “PAA2”, “Jurimer AC-10P, Mw = 5,000”: “PAA3” in the table), polymethacrylic acid (“Polymethacrylic acid, Mw = 100,000” manufactured by Wako Pure Chemical Industries, Ltd.): Polyitaconic acid (“PIA-728, Mw = 3,000” manufactured by Iwata Chemical Industry Co., Ltd .: indicated as “PIA” in the table) was used.
As the zirconium compound, ammonium zirconium carbonate (“Zircosol AC-7, ZrO ₂ equivalent content = 13 mass%” manufactured by Daiichi Rare Elemental Chemical Co., Ltd.) was used. Examples of colloidal silica include W.W. R. “LUDOX AS-30, average particle size = 20 nm, SiO ₂ equivalent content = 30% by mass” manufactured by Grace was used. The solid content and zirconium content of the zirconium compound in terms of zirconium oxide (ZrO ₂ ) relative to 100 parts of the solid content of the polycarboxylic acid polymer used and the polycarboxylic acid polymer in the surface treatment liquid, and Further, Table 1 shows solid compounding amounts of colloidal silica in terms of silicon dioxide (SiO ₂ ).

(Production of surface-treated metal plate)
An aluminum plate (plate thickness 0.28 mm, 3104 alloy plate, A4 size) was used as the metal plate. First, alkali cleaning was performed by dipping in a 2% aqueous solution (60 ° C.) of an alkaline cleaner “Surf Cleaner 420N-2” (trade name) manufactured by Nippon Paint Co., Ltd. for 6 seconds. After alkali washing, water washing, immersion in 2% sulfuric acid aqueous solution (60 ° C.) for 6 seconds, acid washing, water washing and drying. The above-mentioned surface treatment liquid was applied to both the inner surface side and the outer surface side of the obtained metal plate, and was dried in an oven set at 150 ° C. for 60 seconds to prepare a surface-treated metal plate. In addition, the same surface treatment liquid was apply | coated on the same conditions on the can inner surface side and the can outer surface side of the metal plate, and the same surface treatment film layer was formed.

(Production of organic resin-coated surface-treated metal plate)
The obtained surface-treated metal plate was previously heated to a plate temperature of 250 ° C., and a polyester resin film as an organic resin coating layer was thermocompression bonded to both surfaces of the surface-treated metal plate via a laminating roll, and then immediately cooled with water. Thus, an organic resin-coated surface-treated metal plate was obtained. As the polyester resin film on the inner surface of the can, a 12 μm thick polyethylene terephthalate / polyethylene isophthalate copolymer resin film was used. 12 μm thick polyethylene terephthalate / polyethylene isophthalate copolymer resin film (PET / IA) or 12 μm thick polyethylene terephthalate / polyethylene isophthalate copolymer resin and polybutylene terephthalate resin as the organic resin coating layer on the outer surface of the can A film (PET / IA · PBT) was used. Table 1 shows the types of the organic resin coating layer on the outer surface side of the can in each example.

(Preparation of seamless cans)
Paraffin wax was electrostatically applied to both surfaces of the obtained organic resin-coated surface-treated metal plate, and then punched into a circle having a diameter of 156 mm to produce a shallow drawn cup. Next, this shallow drawn cup is subjected to redrawing-ironing and doming, trimming of the edge of the opening, heat treatment at 201 ° C. for 75 seconds, then 210 ° C. for 80 seconds, and necking of the opening end. Then, a flanging process was performed, and a seamless can having a diameter of the can body 211 and a neck portion 206 diameter of 500 ml was produced. Various characteristics of the seamless can were as follows.
Can body diameter: 66 mm
Can height: 168mm
Average thickness reduction rate of can side wall relative to original thickness: 60%

(Content measurement)
Content (mg / m ² ) per unit area of carbon derived from the polycarboxylic acid polymer in the surface treatment film layer of the organic resin-coated seamless can, zirconium derived from the zirconium compound, and silicon derived from colloidal silica is A sample for measurement was prepared by the following procedure, and then measured using a fluorescent X-ray analyzer. First, after producing a seamless can as described in the above section "Preparation of seamless can", a sample obtained by cutting the center portion of the bottom of the obtained seamless can into a size of 2 cm x 2 cm, The sample was immersed in 300 mL of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) at room temperature for 1 hour, and the organic resin coating layer (polyester resin film) was dissolved and removed. A sample was taken out from the HFIP, and the HFIP adhered to the sample was removed to obtain a measurement sample. In the measurement, first, a plurality of standard samples having different carbon contents and known contents of carbon, zirconium, or silicon were measured, and an intensity-content calibration curve was prepared from the strength at this time. Under the same conditions, the measurement samples obtained from the organic resin seamless cans in each example were also measured, and the obtained measurement strength was converted into the content based on the calibration curve, thereby allowing the organic resin-coated seamless cans to The carbon, zirconium and silicon contents in the surface treatment film layer located at the bottom were measured. Table 1 shows the measurement results of the contents of carbon (C), zirconium (Zr), and silicon (Si).
Equipment used: ZSX100e manufactured by Rigaku Corporation
Measurement conditions: Measurement diameter 10 mm
X-ray output: 50 kV-70 mA

(Measurement of peak height ratio (β / α))
The peak height ratio (β / α) of the surface treatment film layer in the obtained organic resin-coated seamless can was calculated by infrared absorption spectrum measurement after preparing a measurement sample by the following procedure. First, after preparing a seamless can as described in the above section “Preparation of seamless can”, a sample obtained by cutting the can body side wall of the obtained seamless can into a size of 8 cm × 4 cm is used as the sample. Was immersed in 300 mL of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) at room temperature for 1 hour to dissolve and remove the organic resin coating layer (polyester resin film). A sample was taken out from the HFIP, and the HFIP adhered to the sample was removed to obtain a measurement sample. Next, the infrared absorption spectrum of the surface treatment film layer on the surface of the measurement sample is measured, and the infrared absorption spectrum obtained by subtracting the absorption peaks of water vapor and carbon dioxide from the infrared absorption spectrum of the obtained surface treatment film layer, The peak height ratio (β / α) of the surface treatment film layer was calculated by the method described in the section “Calculation of peak height ratio (β / α)”.
Equipment used: Digilab FTS7000series
Detector used: MCT detector Accessories used: Advanced Grazing Angle (AGA) manufactured by PIKE
Measurement method: High-sensitivity reflection method (incident angle: 80 ° C., number of integrations: 100 times, reference substrate: gold vapor deposition mirror, using a polarizer to detect only parallel polarization)
Measurement wavenumber region: 4000 to 700 cm ⁻¹

(Comparative Example 4)
As the metal plate, a surface-treated aluminum plate (plate thickness 0.28 mm, 3104 alloy plate, chromium content in the surface treatment film layer: 20 mg / m ² ) subjected to phosphoric acid chromate treatment (chemical conversion treatment) was used. An organic resin-coated surface-treated metal plate was prepared as described in the section “Preparation of an organic resin-coated surface-treated metal plate”, and a seamless can was prepared as described in the section “Preparation of a seamless can”.

[Flange peelability evaluation during heat treatment (evaluation of can aptitude)]
As described in the section “Preparation of seamless cans”, the flange peelability evaluation during heat treatment was performed by trimming the can body, and then using an oven at 201 ° C. for 75 seconds and then at 210 ° C. for 80 seconds. After performing heat treatment for 2 seconds, the opening end (flange forming portion) of the can body was observed with a microscope, and the degree of peeling of the organic resin coating layer was evaluated from the opening end of the can body. The evaluation results are shown in Table 1.
A: Maximum length of peeled portion is less than 0.05 mm ○: Maximum length of peeled portion is from 0.05 mm to less than 0.1 mm Δ: Maximum length of peeled portion is from 0.1 mm to less than 0.2 mm X: The maximum length of the peeled portion is 0.2 mm or more

[Flange peelability evaluation during retort]
The flange part peelability evaluation at the time of retorting was performed by the following method after producing a seamless can as described in the above-mentioned section "Production of seamless can". First, the obtained seamless cans were placed upright in the retort kettle (bottom bottom side down), and subjected to pressure heat sterilization at 125 ° C for 30 minutes with steam in the sealed retort kettle. did. After the pressure heat sterilization treatment, after cooling to room temperature, the seamless can in the retort kettle was taken out and evaluated by observing the peeled state of the organic resin coating layer on the inner and outer flange portions. The evaluation results are shown in Table 1.
◎: No peeling is observed over the entire circumference ○: Partial peeling is observed, but the length of the peeling portion is less than 5% of the total circumference of the can △: Partial peeling is observed, but the peeling The length of the part is 5% or more and less than 10% of the total circumferential length of the can.

[Appearance evaluation of can barrel side wall during retort]
The appearance evaluation of the can barrel side wall during retort was performed by the following method after the seamless can was prepared as described in the section “Preparation of seamless can”. First, 500 g of water was filled into the obtained seamless can, and the lid was tightened according to a conventional method to obtain a filled pack can. The obtained filled pack can is soaked in water and placed in a stainless steel case with the can body side wall on the outer surface of the can fully wet so that the filled pack can faces sideways (the can body side wall is on the lower side). The stainless steel case is placed in a retort kettle, and the side wall of the can body is partially in contact with water. Steam sterilization is performed at 130 ° C for 5 minutes in a sealed retort kettle. Treated. After the above heat and pressure sterilization treatment, after cooling to room temperature, take out the filled pack can in the retort kettle and visually check whether the organic resin coating layer floats or blisters occur on the can body side wall on the outer surface of the can evaluated. The evaluation results are shown in Table 1.
◎: No occurrence of blisters ○: Little occurrence of blisters △: Partial occurrence of blisters ×: Significant occurrence of blisters

  The organic resin-coated seamless can of the present invention has excellent can-making ability, and the organic resin coating layer peels off at the flange portion even when applied under high temperature, high pressure, and high humidity environments such as retort sterilization treatment. In addition, even when retorting is performed under more severe conditions such as steam sterilization by steam in a state where the can body part of the outer surface of the can is in contact with water, the outer surface defect such as blistering is not possible. Since it can exhibit excellent retort resistance that does not occur, it can be suitably used as a metal can container such as a coffee beverage that requires a retort sterilization treatment after filling the contents.

  DESCRIPTION OF SYMBOLS 1 Organic resin coating surface treatment metal base material, 2 Metal base material, 3 Surface treatment film layer, 4 Organic resin coating layer, 10 Organic resin coating seamless can.

Claims (10)

An organic resin-coated seamless can having a surface treatment film layer and an organic resin coating layer on the surface treatment film layer on at least one surface of a metal can, the surface treatment film layer comprising a polycarboxylic acid polymer and a zirconium compound And the maximum absorption peak height (α) in the wave number range of 1660 to 1760 cm ⁻¹ and the maximum in the wave number range of 1490 to 1659 cm ⁻¹ when the infrared absorption spectrum of the surface treatment film layer is measured. An organic resin-coated seamless can having a peak height ratio (β / α) to an absorption peak height (β) of 0.10 to 2.40.   The polycarboxylic acid polymer is a polymer, copolymer, or mixture thereof obtained by polymerization of at least one polymerizable monomer selected from acrylic acid, methacrylic acid, itaconic acid, and maleic acid. The organic resin-coated seamless can according to claim 1.   The organic resin-coated seamless can according to claim 1 or 2, wherein the zirconium compound is a zirconium compound derived from an oxyzirconium salt.   The organic resin-coated seamless can according to claim 3, wherein the oxyzirconium salt is ammonium zirconium carbonate. The content of the polycarboxylic acid polymer in the surface treatment film layer is ² to 100 mg / m ² in terms of carbon, and the content of the zirconium compound is 1 to 80 mg / m ² in terms of zirconium. The organic resin-coated seamless can according to any one of claims 1 to 4.   The surface treatment film layer contains a zirconium compound in an amount of 3 to 67 parts by mass in terms of zirconium with respect to 100 parts by mass of the solid content of the polycarboxylic acid polymer. An organic resin-coated seamless can according to any one of the above.   The organic resin-coated seamless can according to any one of claims 1 to 6, wherein the surface-treated film layer further contains colloidal silica. The organic resin-coated seamless can according to claim 7, wherein the colloidal silica content in the surface treatment film layer is 1 to 200 mg / m ² in terms of silicon.   The organic resin-coated seamless can according to claim 1, wherein the organic resin-coated layer is a polyester resin film.   The organic resin-coated seamless can according to any one of claims 1 to 9, wherein the seamless can is an aluminum seamless can.