JPH1024974A - Cap for aerosol can - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a layer from separating from a metal laminate during drawing and improve a corrosion resistance by forming a cap for an aerosol can by drawing a specific metal laminate covered with a fluororesin layer with the aid of a specific copolymerized resin in such a manner that the resin layer is positioned inside the cap. SOLUTION: A copolymer of glycidyle methacrylate and polyolefin is necessary to be interposed between an aluminum sheet, or a steel sheet, and a fluororesin layer, and polyethylene, polypropylene, poly vinyl acetate, etc., are used as the polyolefin of the copolymer of glycidyle methacrylate and a polyolefin. At least one of faces of the aluminum sheet or the steel sheet is covered with the copolymerized resin and the fluororesin layer, and a covering method is based on an ordinary melt-laminating process. The laminate thus obtained is drawn so that the resin layer forms an inner face of a cap, and is subjected to cold working according to the shape of the cap. By this method, a corrosion resistance is improved, and the cap thus obtained is applicable for an aerosol can employing various kinds of aerosol propellants.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cap which is used by fitting dimethyl ether (DME) or liquefied petroleum gas (LPG) to an upper portion of an aerosol can which sprays the contents in a mist or mousse form using a propellant. .

[0002]

BACKGROUND OF THE INVENTION Dimethyl ether (DME)
Aerosol products that use liquefied petroleum gas (LPG) as a propellant and disperse the contents in a mist or mousse form
Because of its ease of use, pesticides, paints, various cleaners,
It is used for various purposes such as household products such as laundry glue, hair sprays, foaming hair care agents, human body products such as hair-growing tonics, and pharmaceuticals such as athlete's foot medicine and muscle fatigue recovery agents.

As a container used for such an aerosol product, a container body is formed of a simple metal such as tinplate or aluminum, and an epoxy phenol is formed on an inner surface thereof.
Spray coating of paint such as polyvinyl chloride sol, polyamide imide, etc., or double containers with plastic bags inside are used. The cap to be fitted on the upper part of the aerosol can is a simple metal such as tin or aluminum. After spray molding, paint such as epoxyphenol or polyamideimide is spray-coated (for aluminum, anodic oxidation treatment may be applied before spray coating), or coated with a polypropylene film to improve corrosion resistance It is known to form a formed metal plate.

However, since DME and LPG are extremely corrosive, the resin layer of the cap having the above-mentioned structure may be partially peeled off during long-term storage or use. The inventor of the present invention disclosed in Japanese Patent Application No. 5-83533 as an aerosol can cap having excellent corrosion resistance, an aerosol can cap obtained by drawing a laminate having a fluororesin layer coated on at least one surface of an aluminum plate. Proposed.

In the aerosol can cap coated with the above-mentioned fluororesin, the performance of the fluororesin itself is inferior to the adhesion to metal, and the surface of the fluororesin layer is activated by chemical treatment, corona treatment, plasma treatment or the like. By laminating the products, the adhesiveness is improved to withstand the drawing process as a cap for aerosol cans, but the coating peels off at the time of fitting and caulking to attach the cap to the aerosol can body, There is a problem that the corrosion resistance of the part is deteriorated.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above problems and has found a cap having excellent corrosion resistance and workability. The gist of the present invention is that glycidyl is formed on at least one surface of aluminum or steel plate. An aerosol can cap is formed by drawing a metal laminate coated with a fluororesin layer via a copolymer of methacrylate and polyolefin so that the resin layer becomes an inner surface.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The aluminum plate used in the present invention is made of an alloy of aluminum and magnesium (JISH000) in view of workability and strength.
5000 series) can be suitably used. In addition, the surface of the aluminum plate may be subjected to ordinary chemical treatment such as chromate treatment, zirconium treatment or titanate treatment, or physical surface treatment such as electrolytic etching. Plate thickness is 0.2 ~
0.7 mm, preferably 0.3 to 0.6 mm can be suitably used.

The steel sheet used in the present invention may be a tin-plated steel sheet or a nickel-plated steel sheet having a plating film on both sides, or a steel sheet whose surface has been subjected to a chemical conversion treatment. Tin-free steel having a two-layer structure is preferably used. The thickness is 0.2 to 0.7 mm, preferably 0.3 to 0.6
mm is used.

The fluororesin used in the present invention includes polytetrafluoroethylene, a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether,
Examples include, but are not limited to, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, a copolymer of ethylene and tetrafluoroethyl, a copolymer of ethylene and chlorotrifluoroethylene, and the like. . The thickness of the fluororesin layer is 20-150μ
m, preferably 30 to 100 μm can be suitably used.

In the present invention, it is necessary to interpose a copolymer of glycidyl methacrylate and polyolefin between the metal plate and the fluororesin layer, and the polyolefin of the copolymer of glycidyl methacrylate (GMA) and polyolefin used is used. Include polyethylene, polypropylene, vinyl acetate and the like. The composition of the copolymer is
It is a binary copolymer of GMA and ethylene, a ternary copolymer of GMA and ethylene or vinyl acetate, and the like, and has a thickness in the range of 5 to 100 μm, preferably 10 to 60 μm.
Can be suitably used.

The above-mentioned copolymer resin and fluororesin layer are coated on the surface of an aluminum plate or a steel plate. The coating method may be a conventional melt lamination method. The coating material may be a two-layer film formed by a co-extrusion film forming apparatus, or may be sequentially laminated when laminating.
It may be layered.

The obtained laminate needs to be drawn so that the resin layer becomes the inner surface of the cab. The drawing may be performed by a normal cold working method according to the shape of the cap. The cap of the present invention is to be fitted on the upper part of the aerosol can, and can also be used for the uppermost cap for attaching the injection valve and the shoulder part in the middle of the main body.

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

[0014]

【Example】

(Example 1) GM was applied to one side of an aluminum plate (A5052-O material thickness 0.43 mm) whose surface was chromate-treated.
A: A glycidyl methacrylate / ethylene copolymer resin film (thickness: 50 μm) consisting of 6% by weight and ethylene: 94% by weight was melt-laminated and then further laminated.
Using a laminate obtained by laminating a μm-thick ethylene film and a tetrafluoroethylene resin film, a cap having a final product shape was drawn and formed so that the resin became an inner surface. Then, after attaching a valve to this cap, it is fitted by mechanical caulking on the upper part of an aerosol can body (40 mm in diameter x 96 mm high, molded by impact molding and then triple coated with polyamideimide paint on the inner surface). Was.

After the aerosol can was filled with various contents, it was stored in an inverted state at an ambient temperature of 45 ° C. for 3 months, and the condition of the inner surface of the cap was observed. As a result, the propellant is LP
A highly corrosive acidic hair dye containing benzyl alcohol / citric acid / water / N-methylpyrrolidone as a main component in a mixed system of G and DME, and a strong alkaline hair remover (PH1)
2.6 No problem was found on the inner surface of the cap at all with the propellant LPG) as the content. No abnormality was found in the caulking section.

Example 2 An aerosol can cap having the same contents as in Example 1 except that tin-free steel having a two-layer chemical conversion coating of chromium metal as a lower layer and chromium hydrated oxide as an upper layer is used instead of aluminum. And the same storage test as in Example 1 was performed. As a result, no abnormality was found in any of the contents as in Example 1.

(Example 3) A film (thickness: 2) in which a fluororesin coated on the surface of an aluminum plate is made of a copolymer of tetrafluoroethylene and hexafluoropropylene
An aerosol can cap obtained in the same manner as in Example 1 was attached to the aerosol can in the same manner as in Example 1 except that the thickness was 5 μm), and the same storage test as in Example 1 was performed. As a result, no abnormality was found in any of the contents as in Example 1.

Comparative Example 1 The same contents as in Example 1 except that a 50 μm thick ethylene and tetrafluoroethylene resin film were laminated without interposing a copolymer resin film of glycidyl methacrylate and ethylene on the surface of the aluminum plate. The cap for aerosol cans obtained in Example 1 was used.
And the same storage test as in Example 1 was performed. As a result, as a result, the propellant was mixed with benzyl alcohol in a mixed system of LPG and DME.
In the caulking part, when the content contains a highly corrosive acidic hair dye containing citric acid / water / N-methylpyrrolidone as a main component and a strong alkali hair remover (PH12.6 propellant LPG) The contents penetrated, and partial swelling of the coating was observed.

[0019]

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

Claims (1)

[Claims] An aerosol can obtained by drawing a metal laminate in which at least one surface of aluminum or a steel plate is coated with a fluororesin layer via a copolymer of glycidyl methacrylate and polyolefin so that the resin layer becomes an inner surface. cap.