JP2001011552A - Tin alloy sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain superior formability, to prevent the formation of cracks and holes as well as the occurrence of surface roughing at the time of forming, and to provide a cap of a container for whisky, or the like, excellent in external appearance by providing Sn containing specific amounts of Cu. SOLUTION: An alloy, having a composition consisting of, by mass, 0.03-0.40% Cu and the balance Sn, is used. The tin alloy sheet of 0.3 mm thickness is obtained by cold rolling an ingot where a prescribed amount of Cu is added. It is undesirable that Cu content is outside the above range because formability is deteriorated similarly to the case of tin sheet when Cu is less than 0.03% and, when it exceeds 0.40%, the resultant sheet is increased in hardness and formability is reduced. The sheet is of about <=0.5 mm thickness and includes so-called foil. A cap, obtained by working this tin alloy sheet has a reduced surface roughing and is excellent in adhesion to the container body. Further, at the removal of the cap, the cap can be easily broken with fingers and removed because it has tensile strength best suited for breaking with fingers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tin alloy sheet having excellent moldability and, more particularly, to a tin alloy sheet which can be suitably used when manufacturing lids for various beverage containers such as whiskey and wine. .

[0002]

2. Description of the Related Art Conventionally, a lid of a beverage container such as whiskey or wine is made of a lead thin plate or a thin plate obtained by coating a lead thin plate with tin (hereinafter, both are collectively referred to as "lead thin plate").
It is manufactured by the following method. That is, a disk as shown in FIG. 1 is sampled from a lead thin plate, formed into a cylindrical body as shown in FIG. 2, and further formed into a truncated conical cylindrical body as shown in FIG. The lead thin plate is preferable because it has excellent moldability and can be easily formed as shown in the figure.

[0003] However, lead is a toxic substance, and there is a risk of lead poisoning if lead accumulates in the body. In particular, workers engaged in manufacturing lids for beverage containers have a risk of being liable to lead poisoning. In addition, there is also a danger for the final consumer because the final consumer may accidentally immerse the lid of the container in the beverage. For this reason, it has been recently commented that the use of lead sheets should be regulated.

[0004]

Under these circumstances, the present inventors have been working to develop a material that can replace lead thin sheets.
Various studies were performed. For example, an attempt was made to use a tin sheet instead of a lead sheet. However, the tin thin plate has a drawback that it is inferior in moldability and that surface roughening easily occurs.
The rough surface is a fatal defect in the production of lids for containers such as whiskey. Whiskey and the like are important in terms of taste, but appearance is also as important as commercial value. In the case of a thin tin plate, when it is formed, the vicinity of the portion indicated by A in FIG.
In some cases, cracks occurred near the location indicated by. Further, a hole may be opened near a portion indicated by C in FIG. As described above, cracking and puncturing are also fatal drawbacks in the production of lids for containers such as whiskey.

Therefore, the present invention improves the formability by adding a specific element to tin to form a thin plate, and prevents the occurrence of rough surfaces, cracks and holes during the forming. Thus, it is intended to obtain a lid of a container such as whiskey having an excellent appearance.

[0006]

That is, the present invention provides Cu
The present invention relates to a tin alloy thin plate composed of 0.03 to 0.40 mass% (hereinafter, mass% is simply referred to as “%”) and the balance Sn.

[0007] The thin tin alloy sheet of the present invention contains 0.03 to 0.40% of Cu. Cu is 0.03
%, It is not preferable because the moldability becomes poor as in the case of the tin thin plate. If the Cu content exceeds 0.40%, the obtained thin plate becomes hard and the moldability decreases, which is not preferable. Further, the lid obtained by the molding process is not preferable because it is difficult for the lid to adhere to the container body, or it is difficult for the lid to be broken by a finger when opening the lid. In the present invention, a thin plate has a thickness of about 0.5 mm.
The following include what is called a so-called foil.

[0008]

Examples 1 and 2 and Comparative Examples 1 to 4 An ingot (thickness: 50) was prepared by adding Cu in the amount shown in Table 1 to Sn.
(mm, width 200 mm, length 300 mm) was cold-rolled to obtain a tin alloy thin plate having a thickness of 0.3 mm. The tensile strength of the tin alloy sheet was measured and is shown in Table 1. Further, this tin alloy thin plate was subjected to a forming process as shown in FIGS. 1 to 3, and the workability, the rough surface, and the adhesion to the container body were evaluated.

[Table 1] (Note) 1) Workability: The workability during molding was visually evaluated as follows. ○ ・ ・ ・ Good moldability, △ ・
..Molding is somewhat difficult, x ... molding is difficult, xx ...
When molded, cracks and holes occur, and molded products cannot be obtained. 2) Strength: Tensile strength was measured for strength. The unit is kg /
mm ² . 3) Roughness of the surface: After forming, the surface roughness was visually evaluated as follows.・ ・ ・: Less rough skin, △: Some rough skin, ×: Severe rough skin. 4) Adhesion: The lid obtained by molding was attached to the container main body, and the adhesion with the container main body was evaluated by touch as follows.
・ ・ ・: Good adhesion, い な い: not sufficiently adhered to the container body, ×: almost not adhered to the container body,-
··· Unable to evaluate because a molded product cannot be obtained. As shown in Table 1, the tin alloy sheet according to the example had a tensile strength that could be broken by fingers. In addition, the lid obtained by forming the tin alloy sheet according to the example was hardly cracked or pitted, and had good surface roughness and good adhesion. On the other hand, the thin plate according to the comparative example had a tensile strength such that it was hard to be broken by fingers, cracks, holes, or rough skin, or poor adhesion to the container body.

[0009]

As described above, the tin alloy sheet according to the present invention is excellent in formability. That is, cracks and holes are less likely to occur during molding. Further, the lid obtained by molding the tin alloy thin plate according to the present invention has less surface roughness and excellent adhesion to the container body. Furthermore, since the tin alloy thin plate according to the present invention has an optimal tensile strength to be broken by a finger, there is an effect that the lid can be easily torn and opened with the finger when opening the lid. . Therefore, the tin alloy sheet according to the present invention is suitable for use in manufacturing a lid for a beverage container such as whiskey or wine.

[Brief description of the drawings]

FIG. 1 is a perspective view of a disk-shaped thin plate used for forming a lid of a container.

FIG. 2 is a perspective view of a cylindrical body formed by processing a thin disk.

FIG. 3 is a perspective view of a truncated conical cylinder obtained by further molding the cylinder.

Claims (1)

[Claims] 1. A tin alloy sheet comprising 0.03 to 0.40% by mass of Cu and the balance Sn.