U.S. patent application number 12/311297 was filed with the patent office on 2010-02-04 for laminated steel sheet for two-piece can body, two-piece can body made of laminated steel sheet, and method of producing the two-piece can body.
Invention is credited to Hiroki Iwasa, Katsumi Kojima, Hiroshi Kubo, Yuka Nishihara, Yasuhide Oshima, Yoshihiko Yasue.
Application Number | 20100025283 12/311297 |
Document ID | / |
Family ID | 39344285 |
Filed Date | 2010-02-04 |
United States Patent
Application |
20100025283 |
Kind Code |
A1 |
Oshima; Yasuhide ; et
al. |
February 4, 2010 |
Laminated steel sheet for two-piece can body, two-piece can body
made of laminated steel sheet, and method of producing the
two-piece can body
Abstract
Provided is a laminated steel sheet for a can body of a
two-piece can, containing a copolyethylene terephthalate resin
layer containing at least one member selected from the group
consisting of isophthalic acid and cyclohexane dimethanol as a
copolymer component in a proportion of 5 to 20 mol % and having a
crystallization temperature of 120.degree. C. to 140.degree. C. on
at least one side of a steel sheet; and satisfying the following
relationships: r.sub.1.ltoreq.r, 0.1.ltoreq.r.sub.1/R.ltoreq.0.25,
and 1.5.ltoreq.h/(R-r).ltoreq.4, wherein r.sub.1 represents the
minimum radius of the can body, r represents the maximum radius of
the can body, h represents the height of the can body, and R
represents the radius of the laminated steel sheet having a
circular shape before shaping whose weight is the same as that of
the can body. The laminated steel sheet is suitable for a can body
of a two-piece can having a high strain level, and can provide a
two-piece can body which is free from delamination and breakage of
the resin layer.
Inventors: |
Oshima; Yasuhide; (Chiba,
JP) ; Iwasa; Hiroki; (Fukuyama, JP) ; Yasue;
Yoshihiko; (Fukuyama, JP) ; Nishihara; Yuka;
(Chiba, JP) ; Kojima; Katsumi; (Fukuyama, JP)
; Kubo; Hiroshi; (Fukuyama, JP) |
Correspondence
Address: |
FRISHAUF, HOLTZ, GOODMAN & CHICK, PC
220 Fifth Avenue, 16TH Floor
NEW YORK
NY
10001-7708
US
|
Family ID: |
39344285 |
Appl. No.: |
12/311297 |
Filed: |
October 25, 2007 |
PCT Filed: |
October 25, 2007 |
PCT NO: |
PCT/JP2007/071266 |
371 Date: |
March 25, 2009 |
Current U.S.
Class: |
206/524.3 ;
220/62.12; 220/62.15; 413/1 |
Current CPC
Class: |
B32B 1/02 20130101; B21D
51/26 20130101; B32B 15/18 20130101; B32B 27/36 20130101; B32B
27/18 20130101; B65D 7/12 20130101; B65D 1/165 20130101; B21D
51/2615 20130101; B32B 2307/518 20130101; Y10T 428/31681 20150401;
B32B 2307/584 20130101; B32B 2439/66 20130101; B32B 15/08 20130101;
B32B 2307/714 20130101 |
Class at
Publication: |
206/524.3 ;
413/1; 220/62.12; 220/62.15 |
International
Class: |
B65D 8/04 20060101
B65D008/04; B65D 85/72 20060101 B65D085/72; B21D 51/26 20060101
B21D051/26 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 27, 2006 |
JP |
2006-291879 |
Claims
1. A laminated steel sheet for a can body of a two-piece can,
comprising: a copolyethylene terephthalate resin layer containing
at least one member selected from the group consisting of
isophthalic acid and cyclohexane dimethanol as a copolymer
component in a proportion of 5 to 20 mol % and having a
crystallization temperature of 120.degree. C. to 140.degree. C. on
at least one side of a steel sheet; and satisfying the following
relationships: r.sub.1.ltoreq.r, 0.1.ltoreq.r.sub.1/R.ltoreq.0.25,
and 1.5.ltoreq.h/(R-r).ltoreq.4, wherein r.sub.1 represents the
minimum radius of the can body, r represents the maximum radius of
the can body, h represents the height of the can body, and R
represents the radius of the laminated steel sheet having a
circular shape before shaping whose weight is the same as that of
the can body.
2. The laminated steel sheet according to claim 1, wherein a plane
orientation coefficient of the copolyethylene terephthalate resin
layer is 0.04 or lower.
3. A method of producing a can body of a two-piece can, comprising:
a step of shaping, in multiple steps, a circular sheet of the
laminated steel sheet according to claim 1 into a formed body
satisfying the following relationships: r.sub.1.ltoreq.r,
0.1.ltoreq.r.sub.1/R.ltoreq.0.25, and 1.5.ltoreq.h/(R-r).ltoreq.4,
wherein r.sub.1 represents the minimum radius of the can body, r
represents the maximum radius of the can body, h represents the
height of the can body, and R represents the radius of the
laminated steel sheet having a circular shape before shaping whose
weight is the same as that of the can body.
4. The production method of the can body according to claim 3,
wherein a formed body obtained in the middle of the multiple steps
is heated at least once at a temperature ranging from 150.degree.
C. or higher to a melting point of the copolyethylene terephthalate
resin or lower.
5. The production method of the can body according to claim 4,
wherein, the heat treatment is performed when the formed body
obtained in the middle of the multiple steps satisfies the
following relationships: r.sub.1.ltoreq.r,
0.2.ltoreq.r.sub.1/R.ltoreq.0.5, and 1.5.ltoreq.h/(R-r).ltoreq.2.5,
wherein r.sub.1 represents the minimum radius of the can body, r
represents the maximum radius of the can body, h represents the
height of the can body, and R represents the radius of the
laminated steel sheet having a circular shape before shaping whose
weight is the same as that of the can body.
6. A can body of a two-piece can, which is produced by the
production method according to claim 3.
7. A laminated steel sheet for a two-piece can body, satisfying the
following relationships: r.sub.1.ltoreq.r,
0.1.ltoreq.r.sub.1/R.ltoreq.0.25, and 1.5.ltoreq.h/(R-r).ltoreq.4,
wherein h represents the height of the can body, r represents the
maximum radius of the can body, r.sub.1 represents the minimum
radius of the can body, and R represents the radius of the
laminated steel sheet having a circular shape before shaping whose
weight is the same as that of the can body, the laminated steel
sheet comprising a polyester resin layer on at least one side, and
the polyester resin layer comprising terephthalic acid and ethylene
glycol as a main polymer component and at least one member of
isophthalic acid and cyclohexane dimethanol as a copolymer
component in a proportion of 5 to 20 mol %, and having a
crystallization temperature of 120 to 140.degree. C.
8. A can body of a two-piece can, which is produced by the
production method according to claim 4.
9. A can body of a two-piece can, which is produced by the
production method according to claim 5.
Description
TECHNICAL FIELD
[0001] The present invention relates to a laminated steel sheet for
two-piece can bodies, two-piece can bodies made of the laminated
steel sheet, and a method of producing the two-piece can bodies.
More specifically, the present invention relates to a laminated
steel sheet for can bodies of two-piece cans having a high strain
level, such as aerosol cans, a method of producing two-piece can
bodies using the laminated steel sheet, and the obtained two-piece
can bodies.
BACKGROUND ART
[0002] In general, metal cans are roughly classified into two-piece
cans and three-piece cans. Two-piece cans refer to cans formed of
two parts, namely, of a can body integrally formed with a can
bottom and a lid. Three-piece cans refer to cans formed of three
parts, namely, a can trunk, a top lid, and a bottom lid. The can
body of a two-piece can (sometimes abbreviated as "two-piece can
body") has no seam (welded part) so that it gives aesthetically
pleasing appearance. However, the two-piece can aesthetically
pleasing requires a high strain level. Since the can trunk of a
three-piece can has a seam, it is inferior in appearance to the
two-piece can. The three-piece can, however, generally requires
only a low strain level. Therefore, there is a tendency that
two-piece cans have often been used for small-sized high-quality
articles and three-piece cans have often been used for large-sized
low-priced articles in the market.
[0003] As a metal base material for two-piece can bodies having a
high degree of drawing and having a high degree of stretching in
the height direction of the cans (hereinafter sometimes simply
referred to as "having a high strain level"), such as aerosol cans,
among two-piece cans, an expensive thick aluminum sheet is
generally used, and steel sheet raw materials, such as an
inexpensive thin tinplate or tin-free steel, are rarely used. The
reason is that since the two-piece aerosol can has a very high
strain level, a high strain processing, such as drawing or DI, is
difficult to apply to steel sheets, and in contrast, soft metallic
materials, such as aluminum, can be subjected to impact
shaping.
[0004] Under such circumstances, it is industrially very important
to produce a can body of the two-piece can bodies having a high
strain level using an inexpensive, thin, but high-strength steel
sheet material, such as tinplate or tin-free steel.
[0005] In contrast, with respect to usual two-piece cans having a
low strain level, techniques of producing the usual two-piece can
by drawing or DI processing using resin-coated steel sheets
(hereinafter referred to as "laminated steel sheets") as a raw
material have been conventionally known.
[0006] As a resin of covering a laminated steel sheet used for
production of such a two-piece can body having a low strain level,
polyester is generally used. In particular, ionomer compound
materials containing, as a main phase, polyethylene terephthalate,
an ethylene terephthalate-isophthalate copolymer, an ethylene
terephthalate-butylene terephthalate copolymer, and saturated
polyester are mentioned. The above-mentioned polyesters are
designed according to methods of producing a two-piece can body
having a low strain level, and are suitable for the application.
However, no investigation has been conducted on a method of
producing a can body that requires neck-in processing having a high
strain level after drawing as in two-piece aerosol cans, for
example.
[0007] Patent Documents 1 to 3 disclose drawing and DI processing
techniques for resin-coated metal sheets. However, any techniques
disclosed therein are directed toward can bodies having a low
strain level, such as beverage cans and food cans. Specifically,
techniques are disclosed in which, in production of two-piece cans
having a low strain level, internal stress caused by processing is
relieved by performing heat treatment after the processing or the
orientation of resin is positively promoted.
[0008] Patent Documents 2 and 3 disclose performing heat treatment
in an intermediate or final stage while aiming at preventing
delamination of a resin layer or providing barrier properties after
processing. More specifically, Patent Document 2 proposes heat
treatment using an oriented thermoplastic resin for the purpose of
relieving internal stress and promoting oriented crystallization.
The heat treatment has generally been used for beverage cans.
Moreover, Patent Document 2 discloses that the heat treatment is
preferably conducted to a redrawn cup at or below a temperature at
which a coated resin is sufficiently crystallized (at the melting
point or 5.degree. C. lower than the melting point). However,
considering the description of Examples, it is revealed that only
cans having a low strain level are targeted.
[0009] Moreover, Patent Document 3 discloses an example in which a
resin formed of saturated polyester and an ionomer compound is
provided on a coating layer, and then DI processing is performed.
Patent Document 3 describes a processing method in which heat
treatment is performed after drawing, and then DI processing,
necking, and flanging are performed. However, considering the
description of Examples, it is revealed that only cans having a low
strain level are targeted similarly as in Patent Document 2.
[0010] Patent Documents 4 and 5 disclose methods for relieving
internal stress by performing heat treatment on a can principally
at or above the melting point of a resin after shaping the can.
However, the strain level of the obtained can body is still low
considering the specification and the description of Examples.
[0011] Patent Document 1: Japanese Examined Patent Application
Publication No. 7-106394
[0012] Patent Document 2: Japanese Patent No. 2526725
[0013] Patent Document 3: Japanese Unexamined Patent Application
Publication No. 2004-148324
[0014] Patent Document 4: Japanese Examined Patent-Application
Publication No. 59-35344
[0015] Patent Document 5: Japanese Examined Patent Application
Publication No. 61-22626
[0016] More specifically, hitherto, methods of producing high
strain bodies of two-piece cans, such as aerosol cans, using a
laminated steel sheet have never been disclosed.
[0017] The present inventors have attempted to produce high strain
two-piece can bodies by shaping a circular laminated steel sheet
into a cylindrical form having a bottom by DI processing, and then
subjecting a portion around an opening thereof to neck-in
processing. Then, a resin layer is delaminated and broken. These
phenomena are problems peculiar to high-strain shaping, and heat
treatment is apparently effective for overcoming the problems.
However, heat treatment before or after shaping in conventional
findings is not enough for overcoming the problems, and
delamination of a resin layer has not been prevented in a high
strain level area. Thus, even when prior art techniques have been
simply applied to production of can bodies of high strain two-piece
cans, the problem of delamination of a resin layer has not been
overcome. Moreover, another problem such that processability of a
resin layer is deteriorated at steps after a heat treatment step
has arisen.
[0018] The present invention has been made under the
above-described circumstances, and aims to provide a laminated
steel sheet suitable as a raw material for two-piece aerosol cans
which are free from delamination and breakage of a resin layer, a
method of producing a two-piece can body, and a two-piece can
body.
DISCLOSURE OF INVENTION
[0019] The present invention provides a laminated steel sheet for a
can body of a two-piece can, containing: a copolyethylene
terephthalate resin layer containing at least one member selected
from the group consisting of isophthalic acid and cyclohexane
dimethanol as a copolymer component in a proportion of 5 to 20 mol
% and having a crystallization temperature of 120.degree. C. to
140.degree. C. on at least one side of a steel sheet; and
satisfying the following relationships of r.sub.1.ltoreq.r,
0.1.ltoreq.r.sub.1/R.ltoreq.0.25, and 1.5.ltoreq.h/(R-r).ltoreq.4,
wherein r.sub.1 represents the minimum radius of the can body, r
represents the maximum radius of the can body, h represents the
height of the can body, and R represents the radius of the
laminated steel sheet having a circular shape before shaping whose
weight is the same as that of the can body.
[0020] It is preferable that the plane orientation coefficient of
the copolyethylene terephthalate resin layer be 0.04 or lower.
[0021] Moreover, the present invention provides a method of
producing a can body of a two-piece can, including a step of
shaping, in multiple steps, a circular sheet of any one of the
above-described laminated steel sheets into a formed body
satisfying the following relationships of r.sub.1.ltoreq.r,
0.1.ltoreq.r.sub.1/R.ltoreq.0.25, and 1.5.ltoreq.h/(R-r).ltoreq.4,
wherein r.sub.1 represents the minimum radius of the can body, r
represents the maximum radius of the can body, h represents the
height of the can body, and R represents the radius of the
laminated steel sheet having a circular shape before shaping whose
weight is the same as that of the can body.
[0022] In the production method of the can body, it is preferable
to heat the formed body obtained in the middle of the multiple
steps at least once at a temperature ranging from 150.degree. C. or
higher to a melting point of the copolyethylene terephthalate resin
or lower. Moreover, in the production method of the can body, it is
more preferable to carry out the heat treatment when the formed
body obtained in the middle of the multiple steps satisfies the
following relationships of r.sub.1.ltoreq.r,
0.2.ltoreq.r.sub.1/R.ltoreq.0.5, and 1.5.ltoreq.h/(R-r)<2.5,
wherein r, represents the minimum radius of the can body, r
represents the maximum radius of the can body, h represents the
height of the can body, and R represents the radius of the
laminated steel sheet having a circular shape before shaping whose
weight is the same as that of the can body.
[0023] The present invention also provides a can body of a
two-piece can produced by any one of the above-described production
methods.
[0024] Furthermore, the present invention provides a laminated
steel sheet for a can body of a two-piece can satisfying the
following relationships of r.sub.1.ltoreq.r,
0.1.ltoreq.r.sub.1/R.ltoreq.0.25, and 1.5.ltoreq.h/(R-r).ltoreq.4,
wherein h represents the height of the can body, r represents the
maximum radius of the can body, r.sub.1 represents the minimum
radius of the can body, and R represents the radius of the
laminated steel sheet having a circular shape before shaping whose
weight is the same as that of the can body, the laminated steel
sheet containing a polyester resin layer on at least one side and
the polyester resin layer containing terephthalic acid and ethylene
glycol as a main polymer component and at least one member of
isophthalic acid and cyclohexane dimethanol as a copolymer
component in a proportion of 5 to 20 mol % and having a
crystallization temperature of 120 to 140.degree. C.
BRIEF DESCRIPTION OF DRAWINGS
[0025] FIG. 1 is a view illustrating one embodiment of a method of
producing a two-piece can body of the present invention.
BEST MODES FOR CARRYING OUT THE INVENTION
[0026] Hereinafter, the present invention will be described in more
detail.
[0027] The present invention is directed to a can body of a
two-piece can. In particular, the present invention is preferably
used for a can body of a two-piece can having a high strain level,
such as an aerosol can. Then, a two-piece can body intended by the
present invention will be described first.
[0028] FIG. 1 is a view illustrating one embodiment of a method of
producing a two-piece can body of the present invention. FIG. 1
illustrates a step involving drawing (including DI processing) a
circular blank 1 formed of a resin-laminated steel sheet into a
formed body having a bottom, and subjecting the surrounding region
of an opening of the formed body to neck-in processing to thereby
form a two-piece can in which the diameter of the surrounding
region of an opening of the formed body has been reduced. The
"circular" used herein may be any shape that can be subjected to
drawing, DI processing, neck-in processing, and/or flanging, and is
not limited. Thus, a resin-laminated steel sheet used for shaping a
can body can be almost discoidal, distorted discoidal, or
elliptical, as well as discoidal.
[0029] In FIG. 1, 1 denotes a circular blank (blank sheet) before
shaping, 2 denotes a straight wall of a can body (straight wall
that has not yet been subjected to neck-in processing in Step D), 3
denotes a domed portion, 4 denotes a neck-in processed straight
wall, and 5 denotes a tapered portion, i.e., a tapered wall after
neck-in processing.
[0030] Referring to FIG. 1, first, the circular blank 1 is drawn
(including DI processing) in one step or multiple steps to form a
formed body having a bottom and having a predetermined radius
(radius r; the radius of an outer surface of a can) (Step A). Next,
the bottom of the formed body is shaped into a convex form to
thereby form a domed portion 3 (Step B). Furthermore, an opening
end portion of the formed body is trimmed (Step C). Next, the
opening portion of the formed body is subjected to neck-in
processing in one step or multiple steps in such a manner that the
opening portion of the formed body has a predetermined radius
(radius r.sub.1; the radius of an outer surface of a can), thus
forming a desired final formed body (two-piece can body). In FIG.
1, R.sub.0 represents the radius of the circular blank 1 before
shaping (for an elliptical blank, a mean value of the major axis
and the minor axis); h, r, and r.sub.1 represent the height, the
maximum radius, and the minimum radius of the formed body during
shaping or the final formed body, respectively. R denotes the
radius of the circular sheet before shaping whose weight is the
same as that of the final formed body. R.sub.0 is equal to R
calculated from the final formed body plus the trim length, and is
suitably determined. However, since a trimmed portion is waste, it
is industrially preferable to reduce the size of such a trimmed
portion. Thus, R.sub.0 is generally 10% or lower, and 20% at most,
of R. In other words, R.sub.0 is commonly 1 to 1.1 times, and 1 to
1.2 times at most, as large as R. More specifically, when the
present invention is carried out, the timing of heat treatment in
the middle stage can be determined using a value of R=R.sub.0/1.05.
Furthermore, in producing a plurality of can bodies, R can be
determined by trial production.
[0031] More specifically, in Step A in production of a two-piece
can body according to the present invention, the maximum radius r
is equal to the minimum radius r.sub.1, i.e., r=r.sub.1. In Step D,
the relationship of r>r.sub.1 is established.
[0032] The radius R of a circular sheet before shaping whose weight
is the same as that of a final formed body is determined on the
basis of the measured weight of the final formed body. More
specifically, the weight of the final formed body is measured, and
then a dimension (radius) of the circular laminated steel sheet
before shaping whose weight is the same as that of the final formed
body is calculated. The dimension is defined as the radius R of the
circular sheet before shaping whose weight is the same as that of
the final formed body. While an end portion of the can body is
trimmed in the method of producing the can body, the radius R of
the circular sheet before shaping whose weight is the same as that
of the final formed body is independent of influence of the
trimming. Thus, the strain level can be evaluated more
appropriately.
[0033] In a two-piece can produced by drawing (including DI
processing) and neck-in processing of a circular resin-laminated
steel sheet blank, a resin layer is stretched in a height direction
and compressed in a circumferential direction. In a high strain
level, the resin is largely deformed, resulting in breakage of the
resin layer. The present invention utilizes, as an indicator of the
strain level, not only a parameter r.sub.1/R, which indicates the
degree of compression, but also a parameter h/(R-r), which relates
to the stretching in the height direction so as to determine the
indicator of the strain level. This is because, in the case of
shaping a high strain level two-piece can body, the strain level
must be expressed by not only the drawing ratio but also the degree
of stretching. In other words, the degree of deformation of the
resin layer is quantified by defining the strain level by both the
degree of compression and the degree of stretching. Since the resin
layer is likely to delaminate when the resin layer is stretched in
the height direction and compressed in the circumferential
direction, the degree of stretching in the height direction, as
well as the degree of compression, is an important factor.
[0034] In the present invention, in terms of the strain level of
the can body to be finally produced (final formed body), the height
h, the maximum radius r, and the minimum radius r.sub.1 of the
final formed body are determined with consideration of the above
results in such a manner as to satisfy the relationships of
0.1.ltoreq.r.sub.1/R.ltoreq.0.25 and 1.5.ltoreq.h/(R-r).ltoreq.4,
wherein R represents the radius of the circular sheet before
shaping whose weight is the same as that of the final formed
body.
[0035] As described above, the present invention aims to produce a
high strain can body with a laminated steel sheet, which has been
difficult by known techniques. It has been difficult to produce a
high strain can body that satisfies the parameter r.sub.1/R, which
defines the degree of compression, of 0.25 or lower and the
parameter h/(R-r), which defines the degree of stretching, of 1.5
or more simultaneously, with a laminated steel sheet by known
techniques. Thus, in the present invention, r.sub.1/R was adjusted
to 0.25 or lower and h/(R-r) was adjusted to 1.5 or more, as the
strain level of a two-piece can body intended by the present
invention.
[0036] In contrast, when the strain level is high to give the
parameter r.sub.1/R specifying the degree of compression not higher
than 1.0 or the parameter h/(R-r) specifying the degree of
stretching exceeding 4, the number of forming stages is
unnecessarily increased even though the shaping is possible, or the
sheet stretching reaches the limit due to the progress of
hardening, which causes a problem of sheet breakage. Therefore, the
present invention specifies the strain level of producing a
two-piece can intended by the present invention to
0.1.ltoreq.r.sub.1/R and h/(R-r).ltoreq.4.
[0037] When the above results are summarized, a two-piece can body
intended by the present invention is a two-piece can body
satisfying the following relationships of r.sub.1.ltoreq.r,
0.1.ltoreq.r.sub.1/R.ltoreq.0.25, and 1.5.ltoreq.h/(R-r).ltoreq.4,
wherein h represents the height of the two-piece can body, r
represents the maximum radius of the can body, r.sub.1 represents
the minimum radius of the can body, and R represents the radius of
the circular sheet before shaping whose weight is the same as that
of the final formed body.
[0038] The multistep shaping intended by the present invention
includes any of drawing, DI processing, and neck-in processing, or
a combination thereof. In the case of a process including neck-in
processing, the dimension d of the final formed body meets
r>r.sub.1. In the case of a process including no neck-in
processing, the dimension of the final formed body meets r=r.sub.1
(r and r.sub.1 represent the radii of the final formed body).
[0039] Subsequently, a base metal sheet used for the laminated
steel sheet of the present invention will be described.
[0040] The base metal sheet for use in a laminated steel sheet
according to the present invention is a steel sheet, which is lower
in cost than aluminum and is economical. Examples of a preferable
steel sheet include a common tin-free steel or a common tin plate.
It is preferable for a tin-free steel to contain, for example, 50
to 200 mg/m.sup.2 of a chromium metal layer and 3 to 30 mg/m.sup.2,
on a chromium metal basis, of chromium oxide layer on the surface.
It is preferable for a tin plate to contain 0.5 to 15 g/m.sup.2 of
tin. The thickness of the steel sheet may be in, but is not limited
to, the range of 0.15 to 0.30 mm. Furthermore, without any
consideration of the cost, the present technique can be applied to
an aluminum raw material.
[0041] Then, a resin layer of a laminated steel sheet of the
present invention will be described.
[0042] The present inventors have examined the resin layer, and
found that, in order to produce a high strain two-piece can body
using a resin-laminated steel sheet, it is effective and promising
to address the above-described problems to use a substance in which
the orientation state of a polyester resin laminated on a steel
sheet has been suppressed from its usual state. It has also been
revealed that the orientation state of the resin largely depends on
a resin composition and lamination conditions (temperatures,
cooling conditions, etc., at the time of lamination). The present
inventors control the orientation state by specifying a resin
composition, i.e., a copolymer composition of a polyester resin, to
suitable conditions.
[0043] When a high strain two-piece can body is shaped, a resin
tends to orient in the can height direction due to compression
deformation in the circumferential direction and stretching
deformation in the height direction. As important properties
required in a resin layer, it is preferable that it is difficult
for orientation crystallization to proceed at the time of can
shaping from the viewpoints of processability and adhesiveness,
and, in contrast, it is preferable that crystallization proceed
after a can body is produced from the viewpoints of durability and
strength of a film. Thus, conflicting physical properties are
desired.
[0044] As a resin used for a laminated steel sheet for a can body
of a two-piece can, a copolymer resin containing polyethylene
terephthalate as a main component is suitable from the viewpoints
of strength, processability, and durability of a resin. However,
since a polyethylene terephthalate resin is easy to crystallize by
processing, orientation crystallization proceeds and degrades
processability in the case where especially high processing is
performed as in the present invention.
[0045] In general, orientation and crystallization are controlled
by the amount of modification of a copolymer component. When the
amount of copolymer components is small, orientation and
crystallization are likely to proceed, and, in contrast, when the
amount of copolymer components is large, it is difficult for
orientation and crystallization to proceed.
[0046] However, in the present invention, strength and durability
of a film are desired together with high strain processing. More
specifically, a resin structure is desired in which it is difficult
for orientation and crystallization to proceed during shaping of a
can, and, in contrast, crystallization relatively easily occurs at
the time of heat treatment before shaping of a can. The examination
results have revealed that, in the resin structure, the orientation
of a resin film in a laminated steel sheet is important. More
specifically, even in a resin which is difficult to crystallize, it
is easy for crystallization to proceed in a resin having a higher
degree of orientation and it is hard for crystallization to proceed
in a resin having a lower degree of orientation. It has been
revealed that, by appropriately controlling the proportion of a
copolymer component of a polyester resin, i.e., a copolyethylene
terephthalate resin and the orientation state in a laminated steel
sheet, both of high strain processing and strength and durability
of a film by heat treatment can be secured. It should be noted that
the orientation of a resin is controlled by adjusting temperatures
at the time of lamination, cooling conditions, etc. For example, a
crystallization temperature tends to increase when a lamination
temperature is high. The condition can be recognized by the peak
position of a crystallization temperature of thermal analysis. The
degree of orientation is high when the temperature is lower, and
the degree of orientation is low when the temperature is
higher.
[0047] Based on the above-described examination results, in the
present invention, a copolyethylene terephthalate resin layer
containing, as a copolymer component, at least one member selected
from the group consisting of isophthalic acid and cyclohexane
dimethanol in a range of 5 to 20 mol % and having a crystallization
temperature of 120 to 140.degree. C. is used as a resin layer
forming a laminated steel sheet.
[0048] When the proportion of a copolymer component is lower than 5
mol %, orientation and crystallization at the time of processing
are likely to proceed, and thus high strain molding becomes
impossible. In contrast, when the proportion of a copolymer
component exceeds 20 mol %, it is essentially hard for orientation
and crystallization to occur. Thus, even after heat treatment, film
strength and durability are low, and a film is softened, resulting
in insufficient scratching resistance and chemical resistance. As a
copolymer component, isophthalic acid or cyclohexane dimethanol is
suitable because the strength and durability of a resin can be
sufficiently secured by the addition itself. In particular,
isophthalic acid is more preferable for contents in which
especially smell and the like are important because a flavor is
hardly absorbed.
[0049] As a polymer component of a balance, a substance is optimum
which contains terephthalic acid and ethylene glycol as a main
component except for ingredients intermixed during polymerization,
such as diethylene glycol, and a slight amount of additives and
containing terephthalic acid and ethylene glycol in a proportion of
90 mol % or more except for the above-mentioned copolymer
components from the viewpoints of strength, processability, and
durability of a resin.
[0050] With respect to the crystallization temperature, when the
crystallization temperature is lower than 120.degree. C.,
crystallization is very likely to occur, resulting in the formation
of cracks and pinholes in the case of high strain processing. In
contrast, when the crystallization temperature is higher than
140.degree. C., a crystallization rate is very low, resulting in
insufficient crystallization even by heat treatment at 150.degree.
C. or more, which deteriorates strength and durability of a
film.
[0051] Furthermore, in order for a resin layer to follow high
strain shaping of a two-piece can body intended by the present
invention, it has been revealed that the plane orientation of a
resin layer of a laminated steel sheet before forming is also
important. More specifically, a film produced by biaxial
orientation or the like is oriented in the orientation direction in
the plane. When the orientation state maintains a high degree even
after lamination, the film cannot follow processing, sometimes
resulting in breakage. From such viewpoints, the plane orientation
coefficient of a copolyethylene terephthalate resin is preferably
0.04 or lower. In order to produce such a laminated steel sheet
using a biaxially oriented film with a high plane orientation
coefficient, oriented crystals may be dissolved by sufficiently
raising a temperature at the time of lamination. It is a matter of
course that the orientation state of a resin is preferably in the
state specified above.
[0052] Films produced by extrusion are almost non-oriented, and
thus are suitable from the above-described viewpoints. Similarly, a
direct laminating method involving directly laminating a molten
resin to a steel sheet is preferable for the same reason.
[0053] It should be noted that the orientation state of a resin
film can be evaluated usually by X-ray diffraction or by using a
plane orientation coefficient. However, since the film of the
present invention is in a state where there are few or no crystals,
evaluation of the film of the present invention by X-ray
diffraction is sometimes difficult. In contrast, even when it is
attempted to evaluate the orientation of the film of the present
invention using a plane orientation coefficient, the film of the
present invention hardly changes due to orientation in an amorphous
part compared with a crystal part. Therefore, the film of the
present invention may be sometimes sufficiently evaluated even by
using a plane orientation coefficient.
[0054] The present inventors have conducted extensive research on
methods of evaluating orientation states. As a result, it has been
revealed that there is a correlation between the crystallization
temperature measured by thermal analysis and the orientation state
and that when the temperature is higher, the orientation is
damaged, and when the temperature is lower, the orientation
remains. Accordingly, it is preferable that the orientation state
of the resin film of the present invention be evaluated by using a
crystallization temperature indicated by the peak observed by
thermal analysis.
[0055] Then, a laminated steel sheet of the present invention will
be described.
[0056] A laminated steel sheet of the present invention contains
the above-mentioned copolyethylene terephthalate resin layer on at
least one side of the above-mentioned metal sheet. A laminated
steel sheet according to the present invention may contain an
additive, such as a pigment, a lubricant, or a stabilizer, in the
resin layer. A laminated steel sheet according to the present
invention may contain a resin layer having another function in
addition to the resin layer specified in the present invention as
an upper layer or an intermediate layer between the resin layer
specified in the present invention and the base steel sheet.
[0057] When the thickness of a resin layer increases, the internal
stress sharply increases and delamination is likely to occur.
However, in the resin layer specified in the present invention can
be preferably used even for a thick resin layer. The resin
thickness may be suitably determined according to a processing
degree or other required properties. For example, a resin having a
thickness of not less than 10 .mu.m and not more than 50 .mu.m can
be preferably used. In a range of 20 .mu.m or more in which the
resin thickness is large, contribution of the effects of the
present invention is large, and thus such a range is
preferable.
[0058] There is no limitation on methods of laminating a resin to a
steel sheet. Thermocompression methods in which a biaxially
oriented film or a non-oriented film is thermo-compressed and
extrusion methods in which a resin layer is directly coated on the
steel sheet using a T-die can be suitably selected. It has been
confirmed that sufficient effects are obtained by any of the
methods.
[0059] Then, a two-piece can body formed of the laminated steel
sheet of the present invention will be described.
[0060] A two-piece can body of the present invention is obtained by
processing a circular sheet formed of the above-described laminated
steel sheet in multiple steps, and processing the circular sheet
into a formed body in such a manner as to satisfy the following
relationships of r.sub.1.ltoreq.r,
0.1.ltoreq.r.sub.1/R.ltoreq.0.25, and 1.5.ltoreq.h/(R-r).ltoreq.4,
wherein h represents the height of the two-piece can body, r
represents the maximum radius of the can body, r.sub.1 represents
the minimum radius of the can body, and R represents the radius of
the laminated steel sheet having a circular shape before shaping
whose weight is the same as that of the can body.
[0061] When the two-piece can body having a high strain level
specified in the present invention is molded, adhesiveness is
sometimes lowered depending on processing conditions or resin
types. Therefore, it is preferable to secure required adhesiveness
according to the application and specification of a can body. In
this case, it is effective to perform heat treatment, in which a
formed body is heated in such a manner that the temperature is in
the range of 150.degree. C. or higher and the melting point of the
copolyethylene terephthalate or lower, at least one time along the
way of shaping until a final formed body is obtained.
[0062] This heat treatment is intended to relieve internal stress
caused by processing, and has effects of increasing adhesiveness by
relieving the internal stress. More specifically, a high strain can
body specified in the present invention is severely distorted in a
resin layer, and tends to cause high internal stress. As a result,
there is a possibility that a resin layer delaminates due to the
internal stress serving as driving force. Then, by performing an
appropriate heat treatment along the way of shaping as described
above, the internal stress can be relieved to thereby suppress
lowering in adhesiveness. Thus, such heat treatment is preferable.
Moreover, orientation crystallization of a resin proceeds by
performing the heat treatment to increase strength and durability
of a resin layer. Thus, the conditions change depending on
compositions and structures of a resin. Appropriate conditions may
be determined based on performances, such as processability and
durability, of a can.
[0063] When the heat treatment temperature is equal to or lower
than the melting point of the copolyethylene terephthalate resin,
it is easier to maintain an aesthetically pleasing appearance of a
surface layer and to prevent a resin from adhering to other
contactants. The lower limit of heat treatment temperature is
determined with consideration of the efficiency of internal stress
relaxation. More specifically, when the heat treatment temperature
is equal to or higher than the glass transition point (Tg) of the
copolyethylene terephthalate resin, internal stress relaxation
easily progresses. From this point of view, the lower limit
temperature is preferably 150.degree. C. When processing time poses
a problem and productivity is deteriorated, the lower limit
temperature is preferably 170.degree. C. or higher.
[0064] Moreover, when a high strain two-piece can body is formed,
it is sometimes preferable that forming be further performed also
after heat treatment. In such a case, it is preferable to determine
the timing of heat treatment.
[0065] With respect to the timing of heat treatment, it is
preferable to perform heat treatment in a stage of shaping at which
h representing the height of a formed body in an intermediate
stage, r representing the maximum radius of a formed body in an
intermediate stage, and r.sub.1 representing the minimum radius of
a formed body in an intermediate stage satisfy the relationships of
r.sub.1.ltoreq.r, 0.2.ltoreq.r.sub.1/R.ltoreq.0.5, and
1.5.ltoreq.h/(R-r).ltoreq.2.5 relative to the radius R at a
position of a circular sheet before drawing, corresponding to an
opening end part of a final formed body.
[0066] The reason why the timing of heat treatment is determined as
described above resides in the fact that heat treatment is most
effectively performed when a strain level is within the
above-mentioned range. More specifically, heat treatment performed
at a low strain stage leads to internal stress relaxation at a
stage in which the internal stress of the resin is not high. Thus,
the above-described effects are not sufficiently exhibited. When
heat treatment is performed at an excessively high strain stage,
the timing of heat treatment is sometimes late because adhesiveness
of the resin decreases, resulting in possible occurrence of
delamination. From such viewpoints, the upper limit and the lower
limit of a strain level are determined as described above as an
index of a preferable timing of heat treatment.
[0067] Heat treatment can be performed in either or both of Steps A
and D of a production method shown in FIG. 1. The reason why a case
where r and r.sub.1 are the same is included with respect to the
above-described timing of heat treatment resides in the fact that,
in a method of producing a can including neck-in processing, a case
where heat treatment is performed in Step A is sometimes included
or, in a method of producing a can including no neck-in processing,
r and r.sub.1 are the same in diameter. Heat treatment may be
performed a plurality of times according to the necessity of
internal stress relaxation until a final formed body is obtained by
shaping.
[0068] There is no limitation on heat treatment methods. It is
confirmed that the same effect is obtained with an electric
furnace, a gas oven, an infrared oven, an induction heater, etc.
Moreover, a heating rate, a heating time, and a cooling time may be
suitably determined with consideration of both of plus effects due
to internal stress relaxation and minus effects due to orientation
crystallization. Usually, a higher heating rate is more efficient
and a heating time is about 15 seconds to about 60 seconds as a
standard, but the heating rate and the heating time are not limited
to these ranges. A higher cooling rate is preferable because
development of spherulite is easy to avoid.
EXAMPLES
[0069] Hereinafter, examples of the present invention will be
described.
[Production of Laminated Steel Sheet]
[0070] A 0.20 mm thick T4CA tin-free steel (metal Cr layer: 120
mg/m.sup.2, Cr oxide layer: 10 mg/m.sup.2 in terms of metal Cr) was
used as a base sheet. Onto the base sheet, various kinds of resin
layers were formed using a film-lamination method (film
thermocompression) or a direct-lamination method (direct
extrusion). As a resin film, rein pellets produced by Kanebo
Synthetic Fiber Co., Ltd. and Eastman Chemical Company were used.
Resins are suitably mixed in such a manner as to have compositions
shown in Table 1 to thereby produce a single-layer non-oriented
film or biaxially oriented film by a usual method. As a film
laminate, each film having a thickness of 25 .mu.m was laminated on
each side of the original sheet to thereby produce a laminated
steel sheet.
Film Thermocompression 1:
[0071] A film produced by a biaxial orientation method was
thermo-compressed on a steel sheet which had been heated to
.+-.10.degree. C. of the melting point of a resin using a nip roll,
and then was water cooled within 7 seconds by water.
Film Thermocompression 2:
[0072] A non-oriented film was thermo-compressed on a steel sheet
which had been heated to .+-.10.degree. C. of the melting point of
a resin using a nip roll, and then was water cooled within 7
seconds.
Direct Extrusion:
[0073] Resin pellets were kneaded and melted in an extruder. Then
the resultant was extruded through a T-die to laminate onto a
running steel sheet. The resin-laminated steel sheet was nip-cooled
on a cooling roll at 80.degree. C., and was further water
cooled.
[0074] The crystallization temperature and the plane orientation
coefficient of the laminate film on thus prepared laminated steel
sheet were determined by the following procedures. The obtained
results are shown in Table 1.
[Measurement of Crystallization Temperature]
[0075] Using a differential scanning calorimeter (DSC), a
temperature was increased from 0.degree. C. to 280.degree. C. at a
rate of 10.degree. C./min. The peak temperature (crystallization
temperature) of the exothermic peak observed in the range of
100.degree. C. to 200.degree. C. was measured, and the orientation
state was evaluated.
[Determination of Plane Orientation Coefficient]
[0076] Abbe's refractometer was used to determine the refractive
index under the condition of: light source of sodium D ray;
intermediate liquid of methylene iodide; and temperature of
25.degree. C. The determined refractive indexes were Nx in the
machine direction, Ny in the transverse direction, and Nz in the
thickness direction of the film. Then, the plane orientation
coefficient Zs was calculated by the following formula:
Plane orientation coefficient (Ns)=(Nx+Ny)/2-Nz
[Can Shaping]
[0077] A two-piece can body (final formed body) was produced by the
following procedures according to the production method shown in
FIG. 1 using the various laminated steel sheets obtained above. It
should be noted that shaping of the intermediate formed body (Step
C) and the shaping of the final formed body (Step D) were performed
at strain levels to obtain forms shown in Table 2. Drawing in Step
A was performed in 5 steps, and neck-in processing in Step D was
performed in 7 steps. Heat treatment was performed at an
intermediate step during Steps A to D. A can body was heated using
an infrared heating furnace, and was water cooled after termination
of heat treatment. The timing (strain level of the can body at the
timing of performing heat treatment) and heat treatment conditions
of heat treatment are shown in Table 3.
Can Shaping Procedure
[0078] 1) Blanking (Diameter of blank sheet: 66 to 94 mm.phi.) 2)
Drawing and ironing (Step A)
[0079] Through the five steps of drawing, can bodies (intermediate
formed bodies) having a radius r and a height h of the can in a
range of r/R from 0.18 to 0.55 and of h/(R-r) from 0.15 to 3.00,
were produced. In order to produce desired can bodies, ironing was
also applied in combination as required.
3) Forming of dome-shape at can bottom (Step B)
[0080] Bulging was applied to the can bottom to form a
hemispherical shape 6 mm in depth.
4) Trimming (Step C)
[0081] The can top end portion was trimmed by about 2 mm.
5) Diametral Reduction at Opening Portion of Cylinder (Step D)
[0082] Diametral reduction was given to the upper part of the
cylinder. Specifically, the diametral reduction was conducted by a
die-neck method in which the opening end was pressed against a die
in an inside-tapered shape to thereby produce can bodies having
final can shapes given in Table 2.
[0083] In Table 2, h, r, r.sub.1, ha, hc, and R of the final formed
body (Step D) represent a height to an opening end of the final
formed body, a radius of a can body, a radius of a neck formed
part, a height of the can body, a height of the neck formed part,
and a radius of a circular blank before shaping whose weight is the
same as that of the final formed body, respectively. The radius R
of the circular sheet blank was determined as follows. The weight
of a blank sheet before shaping and the weight of a final formed
body after trimming were measured. Based on the measurement
results, the radius of the blank sheet before shaping whose weight
is the same as that of the final formed body was determined. Then,
the determined radius was defined as the radius R of the circular
sheet blank before shaping whose weight was the same as that of the
final formed body.
[0084] For the can bodies produced by the above procedure,
evaluation was given in terms of the processability and corrosion
resistance of the resin layer of the can body. The results of the
evaluation are also shown in Table 3.
[Film Processability Test]
(1) Adhesion Test
[0085] The can body was sheared in a substantially rectangular
shape in the can height direction in such a manner that the width
in the circumferential direction was 15 mm. Only the steel sheet
was sheared linearly in the circumferential direction at a position
10 mm from the bottom in the can height direction. As a result,
there was prepared a test piece having a 10 mm portion in the can
height direction toward the can bottom and a residual portion with
the boundary of the sheared position. At the 10 mm portion, a steel
sheet having 15 mm in width and 60 mm in length was joined
(welded). Then, the 60 mm steel sheet portion was clamped to
forcefully separate the film on the residual portion by about 10 mm
from the sheared position. A peeling test was conducted in
180.degree. direction with the clamping areas of the film-separated
portion and the 60 mm steel sheet portion. The minimum peeling
strength among the observed values was adopted as the index of
adhesion.
[0086] (Evaluation)
[0087] Lower than 4N/15 mm: x
[0088] Not less than 4N/15 mm and lower than 6N/15 mm:
.largecircle.
[0089] 6N/15 mm or more:
(2) Evaluation of Film Defects
[0090] Centering on a position 10 mm from the can upper end, a seal
on which a 15 mm.phi. small aperture was opened was stuck in such a
manner that a measurement area was 15 mm.phi.. Next, the aperture
part was dipped in an electrolyte (KCl: 5% solution, temperature:
normal temperature), and a voltage of 6.2 V was applied to between
the steel sheet and the electrolyte. According to the current value
measured at this time, evaluation was performed as follows.
(Evaluation)
[0091] More than 0.01 mA: x
[0092] More than 0.001 mA and 0.01 mA or lower: .DELTA.
[0093] More than 0.0001 mA and 0.001 mA or lower: .largecircle.
[0094] 0.0001 mA or lower:
[Evaluation of Corrosion Resistance]
[0095] A can body surface film was scratched with a file in such a
manner that the steel sheet of the can body can be energized. An
electrolyte (1% NaCl solution, temperature of 25.degree. C.) was
poured into the can to reach the can spout. Thereafter, a voltage
of 6.2 V was applied to between the can body and the electrolyte.
According to the current value measured at this time, evaluation
was performed as follows.
[0096] [Current Value]
[0097] More than 1 mA: x
[0098] More than 0.01 mA and 0.1 mA or lower: .DELTA.
[0099] More than 0.001 mA and 0.01 mA or lower: .largecircle.
[0100] 0.001 mA or lower:
[0101] As is clear from Table 3, the can bodies C1 to C28, which
are examples of the present invention, exhibited favorable values
both in terms of film processability and corrosion resistance.
[0102] In contrast, C29 to C33, which are comparative examples,
crystallization temperatures are outside the range of the present
invention. Moreover, the content of copolymer components is outside
the range of the present invention in some comparative examples,
and thus the corrosion resistance is poor. Further, in some
comparative examples, the film processability is poor in addition
to the corrosion resistance.
[0103] As described above, it is revealed that, even in the case of
a two-piece can having a high strain level, such as an aerosol
two-piece can, the present invention tends to be free from
delamination and breakage of a film, to excel in recovery
properties of adhesiveness when heat treatment was performed after
processing, and to excel in the film adhesiveness as a can.
Therefore, by the use of the laminated steel sheet of the present
invention as a raw material, a two-piece can body can be obtained
which has a high strain level and is free from delamination and
breakage of a film.
TABLE-US-00001 TABLE 1 Copolyethylene terephthalate resin Copolymer
Melting Lamination Crystallization Plane Testing steel Resin
component point temperature temperature orientation sheet No.
composition content (mol %) (.degree. C.) Lamination method
(.degree. C.) (.degree. C.) coefficient Remarks A1 6% isophtaric
acid - 6 242 Film 220 136 <0.01 Present copolyethylene
thermocompression 2 invention terephthalate example A2 12%
isophtaric acid - 12 226 Film 230 133 <0.01 Present
copolyethylene thermocompression 1 invention terephthalate example
A3 12% isophtaric acid - 12 226 Film 226 128 <0.01 Present
copolyethylene thermocompression 1 invention terephthalate example
A4 12% isophtaric acid - 12 226 Film 222 123 0.01 Present
copolyethylene thermocompression 1 invention terephthalate example
A5 12% isophtaric acid - 12 226 Film 220 121 0.03 Present
copolyethylene thermocompression 1 invention terephthalate example
A6 12% isophtaric acid - 12 228 Direct extrusion 220 125 <0.01
Present copolyethylene invention terephthalate example A7 18%
isophtaric acid - 18 210 Film 210 138 <0.01 Present
copolyethylene thermocompression 1 invention terephthalate example
A8 6% cyclohexane 6 245 Film 245 139 <0.01 Present dimethanol -
thermocompression 1 invention copolyethylene example terephthalate
A9 12% cyclohexane 12 240 Film 237 137 0.01 Present dimethanol -
thermocompression 1 invention copolyethylene example terephthalate
A10 3% cyclohexane 3 250 Film 250 116 <0.01 Comparative
dimethanol - thermocompression 2 example copolyethylene
terephthalate A11 22% cyclohexane 22 208 Film 208 155 <0.01
Comparative dimethanol - thermocompression 1 example copolyethylene
terephthalate A12 12% cyclohexane 12 226 Film 215 118 0.06
Comparative dimethanol - thermocompression 1 example copolyethylene
terephthalate A13 12% cyclohexane 12 228 Film 210 145 <0.01
Comparative dimethanol - thermocompression 2 example copolyethylene
terephthalate
TABLE-US-00002 TABLE 2 Intermediate formed body Final formed body
(Step D) Blank (Step C) Blank Change Can diameter R.sub.0 r h r
r.sub.1 h ha hc diameter R* r.sub.1/R h/(R - r) in sheet shape (mm)
(mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) thickness** B1
41.0 11.0 63.6 11.0 7.8 65.9 47.0 9.9 40.4 0.19 2.24 1.20 B2 47.0
11.0 63.5 11.0 7.8 65.9 47.0 9.9 46.6 0.17 1.85 1.45 B3 35.5 11.0
63.5 11.0 7.8 65.9 47.0 9.9 34.8 0.22 2.77 0.75 B4 33.0 11.0 63.5
11.0 7.8 65.9 47.0 9.9 32.2 0.24 3.11 0.65 *The blank diameter R is
a blank diameter converted in terms of the weight of a final formed
body. **Sheet thickness of a part having the minimum sheet
thickness of a can body/Blank sheet thickness (All thicknesses
refer to a steel sheet thickness)
TABLE-US-00003 TABLE 3 Melting Processing method Evaluation point
of Heat treatment Final Film Can Testing resin Strain level at
condition can processability body steel layer heat treatment
Temperature Time body Film Corrosion No. sheet No. (.degree. C.)
r.sub.1/R h/(R - r) (.degree. C.) (second) shape Adhesion defect
resistance Remarks C1 A3 226 0.27 2.16 210 30 B1 .largecircle.
.circleincircle. .circleincircle. Present invention example C2 A3
226 0.27 2.16 210 60 B1 .largecircle. .circleincircle.
.circleincircle. Present invention example C3 A3 226 0.27 2.16 210
90 B1 .circleincircle. .circleincircle. .circleincircle. Present
invention example C4 A3 226 0.27 2.16 210 120 B1 .circleincircle.
.circleincircle. .largecircle. Present invention example C5 A3 226
0.27 2.16 230 60 B1 .circleincircle. .circleincircle. .largecircle.
Present invention example C6 A3 226 0.27 2.16 240 30 B1
.circleincircle. .largecircle. .largecircle. Present invention
example C7 A3 226 0.27 2.16 160 90 B1 .largecircle.
.circleincircle. .circleincircle. Present invention example C8 A3
226 0.27 2.16 120 60 B1 .largecircle. .largecircle. .largecircle.
Present invention example C10 A3 226 0.38 1.78 210 30 B1
.largecircle. .largecircle. .circleincircle. Present invention
example C11 A3 226 0.47 1.53 210 30 B1 .largecircle. .largecircle.
.largecircle. Present invention example C12 A3 226 0.24 1.78 210 30
B2 .circleincircle. .circleincircle. .circleincircle. Present
invention example C13 A3 226 0.18 2.24 210 30 B2 .largecircle.
.largecircle. .circleincircle. Present invention example C14 A3 226
0.32 2.67 210 30 B3 .largecircle. .circleincircle. .largecircle.
Present invention example C15 A3 226 0.50 2.30 210 30 B3
.largecircle. .largecircle. .circleincircle. Present invention
example C16 A3 226 0.50 0.15 210 30 B3 .largecircle. .largecircle.
.largecircle. Present invention example C17 A3 226 0.34 3.00 210 30
B4 .largecircle. .circleincircle. .largecircle. Present invention
example C18 A3 226 0.40 2.30 210 30 B4 .largecircle.
.circleincircle. .circleincircle. Present invention example C19 A3
226 0.55 2.00 210 30 B4 .largecircle. .largecircle. .largecircle.
Present invention example C20 A1 242 0.27 2.16 220 30 B1
.largecircle. .circleincircle. .circleincircle. Present invention
example C21 A2 226 0.27 2.16 210 30 B1 .circleincircle.
.circleincircle. .circleincircle. Present invention example C22 A4
226 0.27 2.16 210 30 B1 .largecircle. .circleincircle.
.circleincircle. Present invention example C23 A5 226 0.27 2.16 210
30 B1 .largecircle. .largecircle. .circleincircle. Present
invention example C24 A6 228 0.27 2.16 210 30 B1 .largecircle.
.circleincircle. .circleincircle. Present invention example C26 A7
210 0.27 2.16 220 30 B1 .circleincircle. .circleincircle.
.largecircle. Present invention example C27 A8 245 0.27 2.16 220 30
B1 .largecircle. .circleincircle. .largecircle. Present invention
example C25 A8 245 0.27 2.16 150 60 B1 .largecircle. .largecircle.
.largecircle. Present invention example C28 A9 240 0.27 2.16 220 30
B1 .largecircle. .circleincircle. .largecircle. Present invention
example C29 A10 250 0.27 2.16 235 30 B1 .largecircle. .DELTA.
.DELTA. Comparative example C31 A11 208 0.27 2.16 200 30 B1
.circleincircle. .largecircle. .DELTA. Comparative example C32 A12
226 0.27 2.16 210 30 B1 X .DELTA. X Comparative example C33 A13 228
0.27 2.16 210 30 B1 .circleincircle. .largecircle. .DELTA.
Comparative example
INDUSTRIAL APPLICABILITY
[0104] According to the present invention, by forming using the
laminated steel sheet of the present invention, a two-piece can
body can be obtained which has a high strain level and is free from
delamination and breakage of a film. Therefore, the present
invention is preferably used for a can having a high drawing level,
such as an aerosol can.
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