JPH09323774A - Aerosol-can container and aerosol-can cap - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a container used as the main body of an aerosol can which sprays its contents in the form of mist or foam with the aid of liquefied petroleum gas or the like as a propellant, and a cap. SOLUTION: An aerosol-can container which is excellent in corrosion- resistance is obtained in such a way that a metal laminate plate in which at lest one side of an aluminum plate or steel plate is covered with a polyamide resin layer is subjected to a spinning/ironing process so that the resin layer comes inside, thereafter it is coated with dispersion in which an acid-modified polyolefin rein is finely dispersed in an organic solvent, and then it is baked. Also, an aerosol-can cap which is excellent in corrosion-resistance is obtained in such a way that a metal laminate plate in which at least one side of an aluminum plate or steel plate is covered with a polyamide resin layer is subjected to a spinning process so that the resin layer comes inside, thereafter it is coated with dispersion in which the acid-modified polyolefin resin is finely dispersed in an organic solvent, and then it is baked.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container used as a body of an aerosol can for spraying liquefied petroleum gas or the like as a propellant and spraying the contents in a mist or mousse form, and a cap thereof.

[0002]

BACKGROUND OF THE INVENTION As a propellant used in aerosol cans, chlorofluorocarbon gas has been dominant in the past.
The use of CFCs has been regulated due to global environmental problems, and liquefied petroleum gas (hereinafter, referred to as “LPG”) and dimethyl ether (hereinafter, referred to as “DME”) have been used as propellants instead. Usually, the main body of the aerosol can is formed of a metal simple substance, and a container having an inner surface coated with an epoxy resin is used. However, there is a problem that the corrosion resistance to LPG and DME is poor. In addition, there is a container coated with a polyimide amide resin having excellent corrosion resistance instead of the epoxy resin, but there is a problem that it is expensive.

Further, in a method in which a container is formed by drawing and then a resin is applied to the inner surface by a method such as spray coating, corners of the container may not be uniformly coated, or pinholes may occur in the coating resin. There is a problem and it is easily corroded by the contents.Also, in a container formed by drawing a resin on a metal plate with a roll coater or the like in advance and drawing it, the coating film is hard and it is difficult to elongate. Has occurred, and there has been a problem that the contents are easily affected by the portion.

A cap is fitted on the upper part of the aerosol can container. The cap is usually formed by drawing from a single metal and coating the inner surface with an epoxy resin as in the aerosol can container. Some of them are coated with an amide resin, and some of them are drawn on a metal plate with a resin previously coated with a roll coater or the like. However, they have the same problems as those of the aerosol can container.

[0005]

DISCLOSURE OF THE INVENTION The present invention has found an aerosol can container and a cap which have solved the above problems, and the gist of the invention is to provide a polyamide resin layer on at least one side of an aluminum plate or a steel plate. Corrosion resistance is obtained by squeezing and ironing a metal laminated plate coated with a resin layer so that the resin layer is on the inner surface, and then coating a dispersion of acid-modified polyolefin resin dispersed in fine particles in an organic solvent, followed by baking. Excellent aerosol can container and at least one surface of an aluminum plate or a steel plate, a metal laminated plate coated with a polyamide resin layer, after drawing so that the resin layer is the inner surface, fine particles of an acid-modified polyolefin resin in an organic solvent An aerosol can with excellent corrosion resistance, which is obtained by coating a dispersion that has been dispersed in a circular shape and baking it. In the cap.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The aluminum plate used in the present invention is an alloy with manganese of 3,000 series according to JIS H0001 or an alloy with magnesium from the viewpoint of workability and strength.
000 series is preferably used. The surface may be subjected to a chemical conversion treatment such as ordinary chromate treatment, zirconium treatment or titanate treatment, or a physical surface treatment such as electrolytic etching.

The aluminum plate has a thickness of 0.2 mm to
0.7 mm, preferably in the range of 0.3 mm to 0.6 mm can be used, if the thickness is less than 0.2 mm,
Poor internal pressure resistance of the drawn container, 0.7mm thick
If the ratio exceeds 1, the drawability tends to be inferior.

[0008] The steel sheet used in the present invention is a tin-plated steel sheet, a nickel-plated steel sheet having a plating film on both sides,
Alternatively, a steel sheet whose surface is subjected to chemical conversion treatment, a lower layer of metallic chromium, and an upper layer of tin-free steel having a two-layer structure of hydrated chromium oxide are preferably used. The thickness of the steel sheet is 0.2 mm to 0.7 mm, preferably 0.3 m
Those having a range of m to 0.6 mm can be used.

Examples of the polyamide resin with which at least one surface of the aluminum plate or the steel plate is coated include nylon 6, nylon 11, nylon 12, nylon 66, nylon 610, nylon 612, and nylon 6/66 copolymer. In addition, polyamide-based elastomer, impact-resistant nylon and the like can be used, but are not limited to these.

The layer thickness of the polyamide resin is 20 μm to 1
Those having a thickness of 50 μm, preferably 50 μm to 100 μm can be used. If the thickness is less than 20 μm, the corrosion resistance tends to be poor, and if it exceeds 150 μm, the economical efficiency tends to be poor.

A heat-modified coating is preferably provided on the surface of the aluminum plate or steel plate to be bonded to the polyamide resin layer in order to improve the adhesive strength. The heat-modified coating may be epoxy resin, fatty acid, or hydroxy-substituted phenol. Is formed by heat-treating a thin film made of (4) at a temperature of 350 ° C. or higher.

The epoxy resin used for the thin film is a bisphenol type epoxy resin composed of bisphenol A and epochlorohydrin and has a molecular weight of 330 to 3,
000 can be suitably used. Examples of the fatty acid include palmitic acid, stearic acid and oleic acid, and examples of the hydroxy-substituted phenol include salicyl alcohol and hydroxymethyl cresol. The thin film may be applied by a usual roll coater.

The above polyamide resin is coated on at least one side of an aluminum plate or a steel plate, and the coating method may be a usual melt laminating method. The obtained metal laminate is cup-molded so that the resin layer is on the inner surface, and then cold-worked as an aerosol can container by drawing and ironing. Similarly, a cap is obtained by drawing.

The inner surface of the container or cap obtained by drawing and ironing must be coated with a dispersion in which an acid-modified polyolefin resin is finely dispersed in an organic solvent. Examples of the dispersion of the acid-modified polyolefin resin used include acid-modified polyethylene resin modified with an acid component such as maleic anhydride, acid-modified polypropylene resin, and acid-modified ethylene-vinyl acetate copolymer resin. As a coating method, a spray coating method, a dipping method, or the like may be used. As the coating thickness, the thickness after drying is preferably in the range of 3 μm to 50 μm, preferably 5 μm to 30 μm. When the thickness is less than 3 μm, corrosion resistance tends to be poor, and when it exceeds 50 μm, economical efficiency is poor. easy.

Next, it is necessary to bake after coating the above acid-modified polyolefin resin, so that the corrosion resistance can be improved. Baking is performed before necking in the case of 2-piece cans and 200 in the case of 3-piece cans before fitting the bottom.
The container or cap may be heat-treated at a temperature of ℃ or higher. The heating means may be a hot air oven, an infrared heating oven, high frequency heating, or the like.

If a saponified ethylene-vinyl acetate copolymer layer is interposed between the polyamide resin layer and the acid-modified polyolefin resin layer, there is an advantage that the corrosion resistance can be further improved. As the saponified ethylene-vinyl acetate copolymer used, those having an ethylene content of 20 mol% to 60 mol% can be preferably used, and the thickness is 5 μm.
Those having a range of up to 50 μm can be preferably used.

Hereinafter, the present invention will be described in detail with reference to examples.

[0018]

【Example】

Aerosol can container: (Example 1) Chromate treatment at a treatment temperature of 40 ° C to 50 ° C with a treatment liquid containing phosphoric acid, chromic anhydride and fluoride on the surface of an aluminum plate (A5182-O having a thickness of 0.50 mm). And the chromate coating amount is 10 mg / m ²
Was obtained. Bisphenol-type epoxy resin (molecular weight:
380 epoxy equivalent: 180-200) to 1,1,
After dissolving with 1, trichloroethane, the solution was applied using a roll coater so that the thickness after application and drying was 1 μm. The aluminum plate was heat-treated at 350 ° C. or higher to be heat-denatured, and then a nylon 6 film having a thickness of 100 μm was melt-laminated.

52 mm diameter × 10 using the above metal laminated plate
The aerosol can container having a height of 0 mm was drawn and ironed (ironing rate 35%). Then, the inner surface of the container was spray-coated with a maleic anhydride-modified polypropylene resin which was dispersed in toluene so that the solid content was 25% by weight, and then baked at 200 ° C. Fit the cap with the valve attached to the obtained container and fill it with various contents, and then in an upright state 45
It was stored at ℃ × 3 months, the state of the inner surface of the container was observed.

As a result, no abnormality was observed in the acid dye containing LPG as the propellant and containing benzyl alcohol / citric acid / water / N-methylpyrrolidone as a main component.
When the propellant was a mixed system of LPG and DME, with the acidic dye comprising the above components, a slight swelling of the coating was observed on the inner surface side, but it was practically no problem.

(Example 2) Chromate treatment was carried out in the same manner as in Example 1 and a film (80 μm) made of nylon 6 was heat-sealed on the surface of aluminum which had been heat-modified with an epoxy resin, and further thereon. After laminating a film (thickness: 20 μm) made of a saponified ethylene-vinyl acetate copolymer having an ethylene content of 32 mol%, an aerosol can container having a maleic anhydride-modified polypropylene resin coating formed in the same manner as in Example 1. Then, a storage test was conducted in the same manner as in Example 1. As a result, the propellant is LP
No abnormality was observed in any of the acidic dyes composed of a mixed system of G, LPG and DME.

(Embodiment 3) A film made of nylon 6 (100 μm) is formed on the surface of aluminum which has been chromate treated and heat-modified with an epoxy resin in the same manner as in Embodiment 1.
After heat-sealing, the container squeezed and ironed by the same method as in Example 1 was heat-treated in a hot-air stove so that the substance temperature was 300 ° C. or higher, and then by the same method as in Example 1. An aerosol can container having a maleic anhydride-modified polypropylene resin coating film was obtained. A storage test was conducted in the same manner as in Example 1, but no abnormality was observed with any of the acid dyes in which the propellant was LPG or a mixed system of LPG and DME.

(Embodiment 4) Aluminum plate (A5182)
-O thickness 0.50mm) Chromate treatment with a treatment liquid containing phosphoric acid, chromic anhydride and fluoride on both sides at a treatment temperature of 40 ° C to 50 ° C to give a chromate coating amount of 10 mg.
A surface-treated aluminum plate having a surface area of / m ² was obtained. Oleic acid was dissolved in 1,1,1 trichloroethane on both surfaces of the treated surface, and then applied with a roll coater so that the thickness after application and drying would be 1 μm. An aerosol can container was obtained in the same manner as in Example 2 except that the aluminum plate was heat-treated at 350 ° C. or higher to be modified, and a storage test was conducted in the same manner as in Example 2. As a result, no abnormality was observed at all as in Example 2.

(Comparative Example 1) Aluminum plate (A5182)
-O thickness 0.5 Omm) is subjected to chromate treatment at a treatment temperature of 40 to 50 ° C. with a treatment liquid containing phosphoric acid, chromic anhydride and fluoride to give a chromate film amount of 10 mg.
A surface-treated aluminum plate with / m ² was obtained. Bisphenol-type epoxy resin (molecular weight; 380 epoxy equivalent: 180 to 200) was added to one side of the treated surface.
After dissolving with 1,1 trichloroethane, a roll coater was applied so that the thickness after coating and drying would be 1 μm. The aluminum plate was heat-treated at 350 ° C. or higher to modify it, and then a film made of nylon 6 (100 μm
Thickness) was melt laminated.

52 mm diameter × 10 using the above metal laminated plate
The aerosol can container having a height of 0 mm was drawn and ironed (ironing rate 35%). After fitting the cap with the valve attached to the obtained container and filling various contents,
The container was stored in an upright state at 45 ° C for 3 months, and the state of the inner surface of the container was observed.

As a result, even if the propellant is LPG and the acidic dyeing agent contains benzyl alcohol, citric acid, water, and N-methylpyrrolidone as the main components, the acidity of the above components obtained by mixing the propellant with LPG and DME is used. Even with the dye, swelling of the coating film was observed on the entire inner surface, which was a problem in practice.

Aerosol can cap: (Example 5) A treatment temperature of 40 ° C to 50 ° C with a treatment liquid containing phosphoric acid, chromic anhydride and fluoride on the surface of an aluminum plate (A5052-O 0.43 mm thick). Chromate treatment at 10mg / m ²
Was obtained. Bisphenol-type epoxy resin (molecular weight:
380 epoxy equivalent: 180-200) 1,1,1
After being dissolved in trichloroethane, it was applied by a roll coater so that the thickness after application and drying would be 1 μm. The aluminum plate was heat-treated at 350 ° C. or higher to be heat-denatured, and then a nylon 6 film having a thickness of 100 μm was melt-laminated.

Using the above metal laminated plate, a cap for an aerosol can in a final product shape was drawn so that the resin surface was on the inside. Then, using a maleic anhydride-modified polypropylene resin which was dispersed with toluene so that the solid content became 25% by weight, the inner surface was spray-coated, and then baked at 200 ° C. After attaching a valve to the obtained cap, the aerosol can container (40
(mm diameter × 96 mm height).

After filling the aerosol can with various contents, it was stored in an inverted state at 45 ° C. for 3 months, and the state of the inner surface of the cap was observed.

As a result, no abnormality was observed with the acid dye containing LPG as the propellant and benzyl alcohol / citric acid / water / N-methylpyrrolidone as the main component.
When the propellant was a mixed system of LPG and DME, with the acidic dye comprising the above components, a slight swelling of the coating was observed on the inner surface side, but it was practically no problem.

(Embodiment 6) A film (80 μm) made of nylon 6 was heat-fused on the surface of aluminum which had been chromate treated and heat-modified with an epoxy resin in the same manner as in Embodiment 5, and further thereon. A film made of a saponified product of ethylene-vinyl acetate copolymer having an ethylene content of 32 mol% (thickness 20 μm) is laminated on the film, and then a maleic anhydride-modified polypropylene resin film is formed in the same manner as in Example 5 for an aerosol can. A cap was obtained and a storage test was conducted in the same manner as in Example 5. As a result, no abnormality was observed with any of the acid dyes in which the propellant was LPG or a mixed system of LPG and DME.

(Comparative Example 2) A bisphenol-type epoxy resin (molecular weight: 380) was provided on one surface of an aluminum plate (A5052-O thickness 0.43 mm) whose surface was chromated.
Epoxy equivalent: 180 to 200) was dissolved in 1,1,1 trichloroethane, and then coated with a roll coater so that the thickness after coating and drying was 1 μm. Then, 40
After heat treatment at 0 ° C to denature it, nylon 6 (30μ
m) / Acid-modified linear low-density polyethylene resin (10μ
m) / a linear low-density polyethylene resin (40 μm) film (80 μm thick) was melt-laminated.

Using the obtained metal laminated plate, a cap for an aerosol can in the final product shape was drawn so that the resin surface was on the inside. A few% of the obtained caps had fine scratches on the surface.

Further, when the same storage test as in Example 5 was carried out, in the cap having fine scratches, swelling of the resin due to the influence of the contents was observed at that portion.

[0035]

As described above, the aerosol can container and cap of the present invention have excellent corrosion resistance and can be suitably used for aerosol cans using various propellants.

Claims (4)

[Claims] 1. A metal laminated plate in which a polyamide resin layer is coated on at least one surface of an aluminum plate or a steel plate is squeezed and ironed so that the resin layer is on the inner surface, and then an acid-modified polyolefin resin is finely divided into an organic solvent into a fine particle form. An aerosol can container with excellent corrosion resistance, which is obtained by coating the dispersion dispersed in the product and baking it. 2. The aerosol can container according to claim 1, wherein a saponified ethylene-vinyl acetate copolymer layer is interposed between the polyamide resin layer and the acid-modified polyolefin resin layer. 3. A metal laminated plate having a polyamide resin layer coated on at least one surface of an aluminum plate or a steel plate is drawn so that the resin layer is on the inner surface, and then the acid-modified polyolefin resin is dispersed in an organic solvent into fine particles. A cap for an aerosol can with excellent corrosion resistance, which is obtained by baking the coated dispersion. 4. The cap for an aerosol can according to claim 3, wherein a saponified ethylene-vinyl acetate copolymer layer is interposed between the polyamide resin layer and the acid-modified polyolefin resin layer.