U.S. patent application number 10/598534 was filed with the patent office on 2007-06-14 for sealed container and manufacturing method thereof.
This patent application is currently assigned to KIRIN BREWERY COMPANY, LIMITED. Invention is credited to Masaki Nakaya, Akira Shirakura.
Application Number | 20070131639 10/598534 |
Document ID | / |
Family ID | 34917938 |
Filed Date | 2007-06-14 |
United States Patent
Application |
20070131639 |
Kind Code |
A1 |
Nakaya; Masaki ; et
al. |
June 14, 2007 |
Sealed container and manufacturing method thereof
Abstract
It is an object of the present invention to provide a container
in which it is difficult for liquid to drip at a mouth portion
having a good touch sensation by forming a structure in which a
welded portion that was laser welded in a sealed container does not
form a flange, and to carry out the achievement of making polymer
material unnecessary and making excessive material in the seaming
portion unnecessary. Further, it is also an object to construct the
lid and barrel of the vessel by using the same material, thereby
facilitating the recycling of material. The sealed container in
which a container body 1 having an opening 9 is sealed by a lid
portion 3 which closes and covers said opening, comprising a welded
portion 4, 14 in which an outer wall surface of a peripheral
portion 2 of said opening or an edge 12 surface of said opening and
an inner wall surface of said lid portion are laser welded in order
to make it possible for at least an inner wall surface of the
peripheral portion of said opening from an inner wall surface 6 of
said container body to make contact with container contents.
Inventors: |
Nakaya; Masaki; (Tokyo,
JP) ; Shirakura; Akira; (Tokyo, JP) |
Correspondence
Address: |
DARBY & DARBY P.C.
P. O. BOX 5257
NEW YORK
NY
10150-5257
US
|
Assignee: |
KIRIN BREWERY COMPANY,
LIMITED
10-1, Shinkawa 2-chome Chuo-ku
Tokyo
JP
104-8288
|
Family ID: |
34917938 |
Appl. No.: |
10/598534 |
Filed: |
February 24, 2005 |
PCT Filed: |
February 24, 2005 |
PCT NO: |
PCT/JP05/02985 |
371 Date: |
September 1, 2006 |
Current U.S.
Class: |
215/232 ;
220/359.4 |
Current CPC
Class: |
B29C 66/8432 20130101;
B29C 66/91221 20130101; B29C 65/1683 20130101; B29C 66/91216
20130101; B29C 65/1661 20130101; B29C 66/72325 20130101; B29C
65/1635 20130101; B29C 66/73921 20130101; B29C 66/114 20130101;
B29C 66/232 20130101; B29C 66/71 20130101; B29C 66/65 20130101;
B29C 66/72343 20130101; B29C 66/72323 20130101; B29C 66/542
20130101; B29C 66/301 20130101; B29K 2995/0027 20130101; B65B
7/2878 20130101; B29C 66/8322 20130101; B29C 66/1122 20130101; B29C
66/53461 20130101; B29C 65/1664 20130101; B29C 65/76 20130101; B29C
66/112 20130101; Y02W 30/80 20150501; B29C 65/1677 20130101; B29C
66/652 20130101; B29C 66/9131 20130101; B65D 77/2024 20130101; B65D
2543/00842 20130101; B29C 66/939 20130101; B29C 65/1619 20130101;
B29C 66/122 20130101; B29C 66/934 20130101; B29C 66/836 20130101;
B29L 2031/7158 20130101; B65D 2543/00425 20130101; B29C 65/1654
20130101; B29C 66/131 20130101; B29C 66/71 20130101; B29K 2023/06
20130101; B29C 66/71 20130101; B29K 2023/086 20130101; B29C 66/71
20130101; B29K 2023/12 20130101; B29C 66/71 20130101; B29K 2023/18
20130101; B29C 66/71 20130101; B29K 2023/38 20130101; B29C 66/71
20130101; B29K 2025/06 20130101; B29C 66/71 20130101; B29K 2025/08
20130101; B29C 66/71 20130101; B29K 2027/06 20130101; B29C 66/71
20130101; B29K 2027/08 20130101; B29C 66/71 20130101; B29K 2027/18
20130101; B29C 66/71 20130101; B29K 2033/12 20130101; B29C 66/71
20130101; B29K 2033/20 20130101; B29C 66/71 20130101; B29K 2055/02
20130101; B29C 66/71 20130101; B29K 2059/00 20130101; B29C 66/71
20130101; B29K 2067/00 20130101; B29C 66/71 20130101; B29K 2067/003
20130101; B29C 66/71 20130101; B29K 2067/006 20130101; B29C 66/71
20130101; B29K 2069/00 20130101; B29C 66/71 20130101; B29K 2077/00
20130101; B29C 66/71 20130101; B29K 2081/06 20130101; B29C 66/71
20130101; B29K 2096/005 20130101 |
Class at
Publication: |
215/232 ;
220/359.4 |
International
Class: |
B65D 41/00 20060101
B65D041/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 3, 2004 |
JP |
2004-058492 |
Claims
1. A sealed container in which a container body having an opening
is sealed by a lid portion which closes and covers said opening,
comprising a welded portion in which an outer wall surface of a
peripheral portion of said opening and an inner wall surface of
said lid portion are laser welded in order to make it possible for
at least an inner wall surface of the peripheral portion of said
opening from an inner wall surface of said container body to make
contact with container contents.
2. A sealed container in which a container body having an opening
is sealed by a lid portion which closes and covers said opening,
comprising a welded portion in which an edge surface of said
opening and an inner wall surface of said lid portion are laser
welded in order to make it possible for at least an inner wall
surface of the peripheral portion of said opening from an inner
wall surface of said container body to make contact with container
contents.
3. The sealed container according to claim 1, wherein said welded
portion does not form a flange.
4. The sealed container according to claim 1, further comprising a
non-welded portion in which an inner wall surface of a peripheral
portion of said lid portion is not welded to an outer wall surface
of said container body.
5. The sealed container according to claim 1, wherein said lid
portion has a thickness of 0.2 mm or higher.
6. The sealed container according to claim 1, wherein the welded
portion is laser welded in two loop shapes along the periphery of
said opening.
7. The sealed container according to claim 1, wherein said lid
portion has a multilayer structure in which an annular layer having
an inner diameter approximately the same as the opening diameter of
said opening is connected to the inner wall surface side, and the
container seal is opened by peeling apart said lid portion from
said annular layer in the state where said annular layer remains
laser welded to said container body.
8. The sealed container according to claim 1, wherein said
container body and said lid portion are formed from synthetic
resin.
9. The sealed container according to claim 1, wherein said
container is a beverage container.
10. A method of manufacturing a sealed container in which a
container body having an opening is sealed by a lid portion which
closes and covers said opening, comprising the steps of: forming
bonded surfaces by bonding an outer wall surface of a peripheral
portion of said opening and an inner wall surface of said lid
portion; and contacting at least an inner wall surface of the
peripheral portion of said opening from an inner wall surface of
said container body with container contents, wherein said bonded
surfaces are irradiated with a laser to form a welded portion.
11. A method of manufacturing a sealed container in which a
container body having an opening is sealed by a lid portion which
closes and covers said opening, comprising the steps of: forming
bonded surfaces by bonding an edge surface of said opening and an
inner wall surface of said lid portion, and contacting at least an
inner wall surface of the peripheral portion of said opening from
an inner wall surface of said container body with container
contents, wherein said bonded surfaces are irradiated with a laser
to form a welded portion.
12. The method of manufacturing a sealed container according to
claim 10, further comprising the step of providing a laser light
absorbing portion in at least one of an outer wall surface of the
peripheral portion of said opening or an inner wall surface of said
lid portion, or in at least one of an edge surface of said opening
or an inner wall surface of said lid portion.
13. The method of manufacturing a sealed container according to
claim 10, further comprising the step of providing a laser light
absorbing material in a portion of at least one of an outer wall
surface of the peripheral portion of said opening or an inner wall
surface of said lid portion, or in a portion of at least one of an
end portion of said opening or an inner wall surface of said lid
portion.
14. The method of manufacturing a sealed container according to
claim 10, wherein laser irradiation of said welded portion
comprises the step of fixing a laser oscillating element while said
container body and said lid portion are rotated around a rotation
axis formed by the central axis of the container, or carried out by
rotating the laser oscillating element around said container body
and said lid portion around a rotation axis formed by the central
axis of the container.
15. The sealed container according to claim 2, wherein said welded
portion does not form a flange.
16. The sealed container according to claim 2, further comprising a
non-welded portion in which an inner wall surface of a peripheral
portion of said lid portion is not welded to an outer wall surface
of said container body.
17. The sealed container according to claim 2, wherein said lid
portion has a thickness of 0.2 mm or higher.
18. The sealed container according to claim 2, wherein the welded
portion is laser welded in two loop shapes along the periphery of
said opening.
19. The sealed container according to claim 2, wherein said lid
portion has a multilayer structure in which an annular layer having
an inner diameter approximately the same as the opening diameter of
said opening is connected to the inner wall surface side, and the
container seal is opened by peeling apart said lid portion from
said annular layer in the state where said annular layer remains
laser welded to said container body.
20. The sealed container according to claim 2, wherein said
container body and said lid portion are formed from synthetic
resin.
21. The sealed container according to claim 2, wherein said
container is a beverage container.
22. The method of manufacturing a sealed container according to
claim 11, further comprising the step of providing a laser light
absorbing portion in at least one of an outer wall surface of the
peripheral portion of said opening or an inner wall surface of said
lid portion, or in at least one of an edge surface of said opening
or an inner wall surface of said lid portion.
23. The method of manufacturing a sealed container according to
claim 11, further comprising the step of providing a laser light
absorbing material in a portion of at least one of an outer wall
surface of the peripheral portion of said opening or an inner wall
surface of said lid portion, or in a portion of at least one of an
end portion of said opening or an inner wall surface of said lid
portion.
24. The method of manufacturing a sealed container according to
claim 11, wherein laser irradiation of said welded portion
comprises the step of fixing a laser oscillating element while said
container body and said lid portion are rotated around a rotation
axis formed by the central axis of the container, or carried out by
rotating the laser oscillating element around said container body
and said lid portion around a rotation axis formed by the central
axis of the container.
Description
TECHNOLOGICAL FIELD
[0001] The present invention is related to a sealed container in
which contents such as foods and beverages and the like can be
sealed with good sealing performance and there is little dripping
of liquid at a mouth portion having a good touch sensation, and in
particular to a sealed container having a welded portion that was
laser welded and a manufacturing method thereof.
PRIOR ART TECHNOLOGY
[0002] As for a sealed container, for example, as for a beverage
container, various containers such as bottles, cans, plastic
containers and the like are known. In recent years, cans and
plastic containers have been widely used from the viewpoint of
convenience such as the quality of the handling performance thereof
and the like. Of these, cans are in wide circulation because the
container cost is low, the industrial speed is fast, the
transportation efficiency is high and the like. These cans are
usually formed from a cylindrical "body portion" which includes a
bottom and a "lid" which covers the opening of the body portion.
The body portion and the lid portion are adequately connected, and
from the need to seal contents such as foods and beverages and the
like, the cans are made from metal such as aluminum or steel or the
like.
[0003] The connection of the body portion and the lid portion is
carried out by overlapping an end portion of the body portion and
an end portion of the lid portion to form a flange structure which
is then mechanically overlapped by seaming. Because this seaming
process is a process which utilizes the mechanical deformation of a
metal member, the lid portion is generally formed from a thicker
member than the body portion, and is provided with a polymer
material such as styrene-butadiene rubber or polyvinyl chloride or
the like for content sealing. For this reason, a polymer material
is required, and the use amount of metal material becomes
large.
[0004] Accordingly, in order to solve this, with metal cans as a
subject, technologies in which the sealing of cans is carried out
by laser welding have been disclosed (e.g., see Patent Documents
1.about.3).
[0005] However, with regard to plastic beverage containers, it is
difficult to carry out the seaming process, and plastic can
containers for beverages are not distributed. In plastic beverage
containers, the most distributed containers are PET (polyethylene
terephthalate) bottles. In PET bottles, a method in which a cap is
screwed on a bottle mouth portion is used as a sealing method.
However, this cap forms a main cause of large cost increases in the
whole container. Furthermore, because the cap is mainly made of PP
(polypropylene), it becomes a hindrance to recycling.
Patent Document 1: Publication No. W002/42196 A2
Patent Document 2: Japanese Laid-Open Patent Publication No. SHO
63-194885
Patent Document 3: Japanese Laid-Open Patent Publication No. SHO
61-289932
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0006] According to the seaming method carried out when carrying
out the sealing of metal cans, the use of a polymer material and
the excessive use of a can material at the seaming portion are
required and form a main cause of cost increases. In the
laser-welded can container including Patent Document 1, an
examination was carried out for the purpose of reducing the use
amount of materials and making polymer materials unnecessary, and
even though laser welding was tested in place of prior art seaming,
this has not been put to practical use because it could not surpass
the seaming method.
[0007] On the other hand, in the laser-welded can container
including Patent Document 1, because a flange is still formed, even
though seaming is not carried out, this flange lowers the ease of
drinking and promotes liquid dripping. Accordingly, the
disadvantage due to the flange is left unsolved.
[0008] It is an object of the present invention to provide a
container in which it is difficult for liquid to drip at a mouth
portion having a good touch sensation by forming a structure in
which a welded portion that was laser welded in a sealed container
does not form a flange, and to carry out the achievement of making
polymer material unnecessary and making excessive material in the
seaming portion unnecessary. At this time, it is an object to carry
out miniaturization of the lid itself by making a structure in
which a flange is not formed. In the case where the sealed
container is a plastic container, it is an object to improve the
filling speed and transportation efficiency and improve the
recyclability of the container compared to prior art PET bottles.
At this time, because the plastic container has translucency, the
sealed container, as is different from a metal can, is designed to
make the contents visible.
MEANS FOR SOLVING THE PROBLEMS
[0009] From the results of diligent developments to make polymer
materials unnecessary and reduce the use of excessive material in
the seaming portion, the present inventors discovered that the
problems described above can be solved by providing a welded
portion which is laser welded without forming a flange like that of
a seamed portion, whereby the present invention was completed.
Namely, the sealed container according to the present invention is
a sealed container in which a container body having an opening is
sealed by a lid portion which closes and covers said opening, and
includes a welded portion in which an outer wall surface of a
peripheral portion of said opening and an inner wall surface of
said lid portion are laser welded in order to make it possible for
at least an inner wall surface of the peripheral portion of said
opening from an inner wall surface of said container body to make
contact with container contents. Further, a sealed container of
another embodiment of the present invention is a sealed container
in which a container body having an opening is sealed by a lid
portion which closes and covers said opening, and includes a welded
portion in which an edge surface of said opening and an inner wall
surface of said lid portion are laser welded in order to make it
possible for at least an inner wall surface of the peripheral
portion of said opening from an inner wall surface of said
container body to make contact with container contents. In this
regard, the case where said welded portion does not form a flange
is included. When these sealed containers according to the present
invention are given a structure in which the welded portion that
was laser welded does not form a flange, it is difficult for liquid
to drip at a mouth portion having a good touch sensation. Further,
because polymer materials are also unnecessary and there is no
seamed portion, excessive material is also unnecessary.
Furthermore, the lid itself can be miniaturized.
[0010] The sealed container according to the present invention also
includes the case where a non-welded portion in which an inner wall
surface of a peripheral portion of said lid portion is not welded
to an outer wall surface of said container body is provided. In the
case where welding places form lid opening places, the non-welded
portion forms a finger catching portion or a tab, and this improves
the lid opening capability.
[0011] The sealed container according to the present invention also
includes the case where said lid portion has a thickness of 0.2 mm
or higher. When the thickness of the lid portion is made 0.2 mm or
higher to impart rigidity, it can be used as a sealed container
without bursting even in the case where internal pressure is
applied to the container such as by filling with a carbonated
beverage or the like. The laser welding process can carry out
welding even when the thickness of the lid portion is made 0.2 mm
or higher, and this is different from a heat sealing process.
[0012] The sealed container according to the present invention
includes the case where said welded portion is laser welded in two
or more loop shapes along the periphery of said opening. In the
welded portion, the entire surfaces of the connected surfaces may
be welded, but by carrying out laser welding in two or more loop
shapes, the connection strength, the sealing performance and the
easy lid opening capability can be secured with good balance.
[0013] The sealed container according to the present invention
includes the case where said lid portion has a multilayer structure
in which an annular layer having an inner diameter roughly the same
as the opening diameter of said opening is connected to the inner
wall surface side, and the container seal is opened by peeling
apart said lid portion from said annular layer in the state where
said annular layer remains laser welded to said container body. By
separating the portion of the lid portion welded to the container
body and the portion which is peeled apart when the container is
opened, it is possible to impart a high sealing performance and an
easy container opening capability at the same time.
[0014] In the sealed container according to the present invention,
said container body and said lid portion are preferably formed from
synthetic resin. The filling speed, transportation efficiency and
the recyclability of the container are improved. Furthermore, the
container contents are visible.
[0015] The sealed container according to the present invention
includes the case where said container is a beverage container.
[0016] The method of manufacturing a sealed container according to
the present invention is a method of manufacturing a sealed
container in which a container body having an opening is sealed by
a lid portion which closes and covers said opening, and includes a
process in which after forming bonded surfaces by bonding an outer
wall surface of a peripheral portion of said opening and an inner
wall surface of said lid portion in order to make it possible for
at least an inner wall surface of the peripheral portion of said
opening from an inner wall surface of said container body to make
contact with container contents, said bonded surfaces are
irradiated with a laser to form a welded portion. The method of
manufacturing a sealed container of another embodiment according to
the present invention is a method of manufacturing a sealed
container in which a container body having an opening is sealed by
a lid portion which closes and covers said opening, and includes a
process in which after forming bonded surfaces by bonding an edge
surface of said opening and an inner wall surface of said lid
portion in order to make it possible for at least an inner wall
surface of the peripheral portion of said opening from an inner
wall surface of said container body to make contact with container
contents, said bonded surfaces are irradiated with a laser to form
a welded portion. By including this process, connecting is very
easy because it can be carried out just by irradiating the
connected surfaces with the laser, and there is no formation of a
flange at the welded portion which is the connection place.
[0017] The method of manufacturing a sealed container according to
the present invention preferably includes a process which provides
a laser light absorbing portion in at least one of an outer wall
surface of the peripheral portion of said opening or an inner wall
surface of said lid portion, or in at least one of an edge surface
of said opening or an inner wall surface of said lid portion. This
is preferred in the case of laser welding transparent plastic which
does not absorb laser light, or in the case of laser welding
plastic which is not transparent plastic but does not have an
absorption band for the wavelength of the laser light. The laser
has characteristics which make it possible to irradiate only a fine
area. By providing an absorption portion in the connected portion,
it is possible to act the laser only in such portion. Namely, by
suitably moving the irradiation position of the laser, fusion can
be carried out by noncontact easily with good precision even if
there are contours or undulations which make mechanical contact
complicated, whereby sealing is possible, and this is different
from seaming and heat sealing.
[0018] The method of manufacturing a sealed container according to
the present invention preferably includes a case which provides a
laser light absorbing material in a portion of at least one of an
outer wall surface of the peripheral portion of said opening or an
inner wall surface of said lid portion, or in a portion of at least
one of an end portion of said opening or an inner wall surface of
said lid portion. The laser can be acted in the place provided with
the absorption material in the same way as for the absorption
portion described above. Accordingly, by suitably moving the
irradiation position of the laser, fusion can be carried out by
noncontact easily with good precision even if there are contours or
undulations which make mechanical contact complicated, whereby
sealing is possible, and this is different from seaming and heat
sealing.
[0019] In the method of manufacturing a sealed container according
to the present invention, laser irradiation to said welded portion
is preferably carried out by fixing a laser oscillating element
while said container body and said lid portion are rotated around a
rotation axis formed by the central axis of the container, or
carried out by rotating the laser oscillating element around said
container body and said lid portion around a rotation axis formed
by the central axis of the container. It is possible to carry out
laser welding with good precision.
EFFECT OF THE INVENTION
[0020] In the sealed container of the present invention, because
the welded portion that was laser welded does not form a flange,
there are no uneven shapes, the touch sensation of the mouth
portion is good, and liquid dripping rarely occurs. This is
achieved even without the use of polymer materials and excessive
material of a flange portion which were required in metal cans.
Further, the lid portion can be miniaturized. Furthermore, when the
sealed container is a plastic container, because it does not
require a screw-in type lid, the filling speed and transportation
efficiency can be improved, and the recyclability of the container
can be improved because the container body and the lid portion can
be made of the same raw material. At this time, because it has
translucency, the container contents become visible in the same way
as a glass bottle. Further, in accordance with the method of
manufacturing a sealed container of the present invention,
connecting is very easy because it can be carried out just by
irradiating the connected surfaces with the laser, and there is no
formation of a flange at the connection place.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 shows partial vertical cross-sectional schematic
drawings of a sealed container according to the present
embodiments, wherein (a) is a first embodiment, (b) is a second
embodiment, and (c) is a third embodiment.
[0022] FIG. 2 shows a partial vertical cross-sectional schematic
drawing of a fourth embodiment of a sealed container according to
the present embodiments.
[0023] FIG. 3 shows partial vertical cross-sectional schematic
drawings of a fifth embodiment of a sealed container according to
the present embodiments, wherein (a) and (b) show the sealed
container at the sealing time, and (c) shows sealed container at
the lid opening time.
[0024] FIG. 4 is a schematic process drawing (first manufacturing
embodiment) showing various manufacturing processes for the sealed
container according to the present embodiments.
[0025] FIG. 5 is a schematic process drawing (second manufacturing
embodiment) showing various manufacturing processes for the sealed
container according to the present embodiments.
DESCRIPTION OF SYMBOLS
[0026] 1, 11, 21, 31, 41, 61: container body [0027] 2, 22, 32:
peripheral portion of opening [0028] 3, 13, 23, 33, 43, 62: lid
portion [0029] 4, 14, 24, 34, 44: welded portion [0030] 5, 15, 25,
35: non-welded portion [0031] 6, 16, 26, 36: inner wall surface of
peripheral portion of opening [0032] 9, 19, 29, 39, 49: opening
[0033] 12: edge surface of opening [0034] 27: tab [0035] 37: catch
portion [0036] 38, 48: shoulder [0037] 47: tab [0038] 50: annular
layer [0039] 63a: lid portion conveying means [0040] 63b: lid
portion supplying means [0041] 64: lid portion arranging means
[0042] 65: laser generating means [0043] 66: bonded portion [0044]
67: laser generator rotating means [0045] 68: rotation table [0046]
69: turntable [0047] 70: defective container removing means [0048]
100: sealed container
PREFERRED EMBODIMENTS OF THE INVENTION
[0049] The present invention is described in detail below with
reference to preferred embodiments, but it should not be
interpreted that the present invention is limited to these
descriptions. First, a sealed container according to the present
embodiments will be described with reference to FIGS. 1.about.3.
Further, the same symbols are applied to the same members or same
parts.
[0050] A partial vertical cross-sectional schematic drawing of a
first embodiment of a sealed container according to the present
embodiments is shown in FIG. 1(a). A sealed container 100 according
to the first embodiment is a sealed container in which a container
body 1 having an opening 9 is sealed by a lid portion 3 which
closes and covers the opening 9, and includes a welded portion 4 in
which an outer wall surface of a peripheral portion 2 of the
opening 9 and an inner wall surface of the lid portion 3 are laser
welded in order to make it possible for at least an inner wall
surface 6 of the peripheral portion of the opening 9 from the inner
wall surface of the container body 1 to make contact with the
container contents.
[0051] A partial vertical cross-sectional schematic drawing of a
second embodiment of a sealed container according to the present
embodiments is shown in FIG. 1(b). A sealed container 200 according
to the second embodiment is a sealed container in which a container
body 11 having an opening 19 is sealed by a lid portion 13 which
closes and covers the opening 19, and includes a welded portion 14
in which an edge surface of the opening 9 and an inner wall surface
of the lid portion 13 are laser welded in order to make it possible
for at least an inner wall surface 16 of the peripheral portion of
the opening 19 from the inner wall surface of the container body 11
to make contact with the container contents.
[0052] The sealed container of the first embodiment and the sealed
container of the second embodiment have the same structure with the
exception that the laser welding places in the container bodies are
different. In the sealed container of the first embodiment, because
a large surface area of the welded portion 4 is obtained, the
pressure resistance strength can be made large.
[0053] The container bodies 1, 11 and the lid portions 3, 13 may be
formed from any raw material so long as it is a raw material in
which laser welding is possible, but restrictions which also depend
on the container contents are applied. For example, if it is a
beverage container, from the viewpoint of quality preservation of
the contents, it needs to be inert to the container contents.
Furthermore, it is preferably provided with a gas barrier property
for oxygen and the like. Further, in the case of filling a
carbonated beverage, it needs to be formed from a raw material
having pressure resistance. From this kind of viewpoint, the
container bodies 1, 11 and the lid portions 3, 13 are preferably
formed from a plastic material or a metal material such as aluminum
or steel or the like. The container bodies 1, 11 and the lid
portions 3, 13 are preferably formed from the same raw material
from the viewpoint of recyclability. In particular, they are
preferably formed from a plastic material, whereby welding is
possible without heating to a high temperature by laser welding.
When they form a laser-welded plastic sealed container, the filling
speed and transportation efficiency are improved and the
recyclability of the container is improved compared to prior art
PET bottles. At this time, because the plastic container has
translucency, it is different from a metal can and the contents can
be made visible. Further, when compared to a can structure, sealing
can be carried out even for shapes that can not be seamed, and it
is possible to carry out sealing using a smaller lid than the case
where seaming is carried out.
[0054] As for the resin used when forming the plastic container of
the present invention, polyethylene terephthalate (PET) resin,
polybutylene terephthalate resin, polyethylene naphthalate resin,
polyethylene resin, polypropylene (PP) resin, cycloolefin copolymer
resin (COC, cyclic olefin copolymer), ionomer resin,
poly-4-methylpentene-1 resin, polymethyl-methacrylate resin,
polystyrene resin, ethylene-vinyl alcohol copolymer resin,
acrylonitrile resin, polyvinyl chloride resin, polyvinylidene
chloride resin, polyamide resin, polyamide-imide resin, polyacetal
resin, polycarbonate resin, polysulfone resin, or ethylene
tetrafluoride resin, acrylonitrile-styrene resin, and
acrylonitrile-butadiene-styrene resin can form illustrative
examples. Of these, PET is particularly preferred. Further, in the
case where the container bodies 1, 11 and the lid portions 3, 13
are made of plastic, the inner surfaces thereof or the outer
surfaces thereof or both surfaces thereof may be coated with a gas
barrier property thin film such as a DLC (diamond-like carbon)
film, a DLC film containing Si, a polymer-like carbon film, a SiOx
film or the like. This is because a high gas barrier property is
preferred in the case of a plastic container for beverages.
Further, in the case where the gas barrier property thin film
absorbs the laser, the laser light receiving portion generates
heat. Accordingly, even when a container is formed from a
transparent resin which does not absorb laser light, by forming a
gas barrier property thin film, the welding efficiency is good
without having to separately provide an absorption portion.
[0055] In the sealed container of the first embodiment and the
sealed container of the second embodiment, by (1) making it
possible for the inner wall surfaces 6, 16 to make contact with the
container contents, and (2) connecting either the outer wall
surface of the peripheral portion 2 of the opening 9 or the edge
surface 12 of the opening 19 to the inner wall surface of the lid
portion 3, the welded portions 4, 14 do not form a flange. Further,
because the connected portion is formed just by flatly overlapping
and welding the container body and the lid portion, the lid portion
itself can be miniaturized. Furthermore, in the present invention,
the surface which can make contact with the container contents in
the lid portion is described as the inner wall surface of the lid
portion.
[0056] So long as the above-described connecting structure is
satisfied, the shape of the lid portion and the shape of the
container body, in particular the shape of the opening can be
suitably changed. In the sealed container 100 of the first
embodiment, the container body 1 has a shape in which the wall
thereof is folded toward the inside of the container, and the
opening 9 is formed at a position which is lower than the height of
the folded portion. By giving the container body 1 this kind of
shape, it forms a shape in which a straw can be easily inserted in
the opening 9 at the time the lid is opened. The lid portion 3 has
a size which at least covers the opening 9 in order to make it
possible to seal the opening 9, and is formed so as to follow the
shape of the outer wall surface of the container body 1 surrounding
the opening 9. In this way, bonding surfaces which form the
connected portion that forms the welded portion 4 are formed.
[0057] The outer edge portions of the openings 9, 19 of the
container bodies 1, 11 are preferably laser welded up to the
peripheral portions 2, 12 in order to prevent retention of the
container contents.
[0058] On the other hand, non-welded portions 5, 15 in which inner
wall surfaces of the peripheral portions of the lid portions 3, 13
are not welded to the outer wall surfaces of the container bodies
1, 11 may be included in the sealed container of the first
embodiment and the sealed container of the second embodiment. In
FIGS. 1(a) and 1(b), the non-welded portions 5, 15 form unsealing
tabs. By providing the non-welded portions 5, 15, in the case where
welding places form lid opening places, the non-welded portions 5,
15 can be easily caught by fingers when the lid is to be opened,
and this makes it possible to impart an easy lid opening
capability.
[0059] Further, in addition to the containers of the type where the
welded portions 4, 14 are peeled apart to open the lid, the sealed
container according to the present embodiments also includes
containers of the type where the welded portions 4, 14 are not
peeled apart, for example, where the seal is broken at a spout
provided in the lid portion separate from the openings 9, 19 by
plug opening means such as a pull tag or the like.
[0060] The lid portions 3, 13 preferably have a thickness of 0.2 mm
or higher, and more preferably 0.3 mm or higher. In the case where
the lid portions 3, 13 are sheets less than 0.2 mm, the container
body and the lid portion can be fused and welded by a heat sealing
process, without laser welding the welded portions 4, 14. However,
in the case where the thickness of the lid portions 3, 13 is 0.2 mm
or higher, it becomes difficult to apply the heat sealing process,
and if the shapes of the connecting surfaces are complex shapes,
the application of the heat sealing process itself is difficult. In
contrast to this, in the laser welding process, for raw materials
such as plastic and the like which are transparent materials, there
is no heating so long as the laser is not absorbed. Accordingly,
laser welding is possible even when the thickness of the lid
portion 3, 13 is 0.2 mm or higher. In the case where the thickness
of the lid portion 3, 13 is 0.2 mm or higher, because the lid
portion itself is imparted with rigidity, the strength of the
sealed container, in particular the pressure resistance is
improved. Further, the thickness of the container bodies 1, 11 is
preferably made 0.2 mm or higher in order to impart rigidity.
[0061] Next, a partial vertical cross-sectional schematic drawing
of a third embodiment of a sealed container according to the
present embodiments is shown in FIG. 1(c). In a sealed container
300 according to the third embodiment, an end portion of a lid
portion 23 is provided with a tab 27 for opening the lid. Because a
truncated cone shape is formed from a container body 21 up to an
opening 29, a mouth portion which makes it easy to drink is formed.
Further, the lid portion can be miniaturized, and the use amount of
lid material can be reduced.
[0062] Next, a partial vertical cross-sectional schematic drawing
of a fourth embodiment of a sealed container according to the
present embodiments is shown in FIG. 2. In a sealed container 400
according to the fourth embodiment, a welded portion 34 follows the
periphery of an opening 39, and laser welding is carried out in two
loop shapes. In the welded portion, the entire surface of the
connecting surfaces may be welded, but by carrying out laser
welding in two loop shapes, the connection strength and sealing
performance are the same as the case of total surface welding, and
this makes it possible to open the lid more easily. Of course, the
welded portion 34 may be laser welded in three or more loop
shapes.
[0063] Further, in the sealed container according to the present
embodiment, in order to prevent the lid from opening when the
non-welded portions rub during transport, the container body is
provided with a shoulder 38 as in the sealed container 400 shown in
FIG. 2 to form a structure which guards the non-welded portion 35.
Further, in the case where a shoulder 38 is provided, when it is
difficult for fingers to catch the non-welded portion 35, a catch
portion 37 of the non-welded portion 35 for making it easy for
fingers to catch the non-welded portion 35 may be removed from the
outer wall surface with the container body 31.
[0064] In the sealed container of the first.about.fourth
embodiments, in the case where the lid is opened by peeling apart
at the welded portion, peeling apart is carried out at the
connecting surfaces of the container body and the lid portion, or
peeling apart is carried out at an inner wall portion of the
container body or peeling apart is carried out at an inner wall
portion of the lid portion. These peeling apart places can be
controllably selected because they correspond to places where laser
absorbing portions are provided. In the case where a peeling apart
place forms an end portion of the mouth portion, from the viewpoint
of a good touch sensation, preferably peeling apart is carried out
at the connecting surfaces of the container body and the lid
portion, or peeling apart is carried out at the inner wall surface
of the lid portion.
[0065] Next, a schematic drawing of a fifth embodiment of a sealed
container according to the present embodiments is shown in FIG. 3.
FIG. 3(a) is a side view drawing, FIG. 3(b) is a partial vertical
cross-sectional schematic drawing when FIG. 3(a) is rotated
90.degree., and FIG. 3(c) is a partial vertical cross-sectional
schematic drawing when the lid is opened. A sealed container 500
according to the fifth embodiment has a multilayer structure in
which an annular layer 50 having an inner diameter roughly the same
as the opening diameter of an opening 49 is connected to the inner
wall surface side of a lid portion 43. The connecting surfaces of
the annular layer 50 and a container body 41 are laser welded to
form a welded portion 44. Further, as shown in FIG. 3(c), the
container seal is opened by peeling apart the lid portion 43 from
the annular layer 50 in the state where the annular layer 50
remains laser welded to the container body 41. A tab 47 provided on
an end portion of the lid portion 43 can be easily caught by
fingers, and a shoulder 48 prevents the tab 47 from being caught by
rubbing during transport of the container. In the sealed container
of the fifth embodiment, by separating the portion of the lid
portion 43 welded to the container body 41 and the portion which is
peeled apart when the container is opened, it is possible to impart
a high sealing performance and an easy container opening capability
at the same time.
[0066] In the sealed container of the first.about.fifth
embodiments, the welded portion does not form a flange. Further, in
the first.about.fourth embodiments, the peeling apart of the welded
portion to form a mouth portion makes it possible to provide a
mouth portion having a good touch sensation. Further, because the
container contents do not adhere around a flange, there is little
liquid dripping. Furthermore, because the lid portion can be
miniaturized, the lid surface area becomes small, and the total
pressure (pressure from the inside) applied to the entire lid
portion becomes small when filled with contents such as a
carbonated beverage or the like, whereby the pressure resistance is
improved.
[0067] Next, methods of manufacturing a sealed container according
to the present embodiment will be described with reference to FIG.
4 and FIG. 5. First, a description will be given for the process
(first manufacturing embodiment) shown in FIG. 4. First, in step
S1, a container body 61 that was filled with contents is introduced
to a laser welding machine by conveying means (not shown in the
drawing) such as a conveyor or the like. At this time, in the case
where the contents are foaming, foam breaking is carried out, and
carbon dioxide gas purging or nitrogen gas purging is carried
out.
[0068] Next, in step S2, a lid portion 62 is conveyed by lid
portion conveying means 63a to lid portion supplying means 63b. The
lid portion supplying means 63b supplies one lid portion 62 to the
opening of one container body 61.
[0069] Next, in step S3, lid portion arranging means 64 aligns the
lid portion 62 with the opening of the container body 61 to produce
bonding surfaces which will form connecting surfaces, and applies a
suitable pressure so that the lid portion 62 and the opening of the
container body 61 do not slip out of alignment. For example, in
order to bond the lid portion to the container body, the lid
portion is pressed above the lid portion by a rod-shaped member.
The container body is pressed in indirectly by the pressing of the
lid portion. The force pressure of the rod-shaped member is
detected by a pressure sensor. The pressure sensor may be a
proximity sensor for detecting the lid portion, but in general the
sensitivity of a magnetic proximity sensor is not good for plastic.
Accordingly, a pressure sensor or a laser displacement gauge is
preferred. The detection value of the pressure that presses the lid
portion 62 into the opening of the container body 61 detected by a
pressure sensor or a laser displacement gauge is preferably
incorporated in the lid portion arranging means 64.
[0070] Next, in step S4, the container body 61 with the lid 62 kept
in alignment is placed on a turntable 69. Each container body 61
and the lid portion 62 thereof on the turntable 69 are rotated by a
rotation table 68 which rotates the container around its own axis.
At this time, a bonded portion 66 of the container body 61 and the
lid portion 62 is irradiated with a laser by laser generating means
65. Irradiation with the laser can be carried out in a spot shape,
a line shape or a ring shape, for example. The laser irradiation
shape is suitably selected by the positional relationship between
the laser generating means 65 and the bonded portion 66. At this
time, the laser intensity is preferably monitored by monitoring the
laser output. Further, the spot position of the laser is preferably
monitored by monitoring light generation or heat generation by a
photosensitive sensor or a temperature sensor such as an infrared
sensor or the like. The welding of plastic is preferably monitored
by monitoring light generation or heat generation by a
photosensitive sensor or a temperature sensor. An imaging sensor
such as a CCD or the like may be used at the same time.
[0071] The laser oscillating element installed in the laser
generating means 65 can be a semiconductor laser, a gas laser such
as a carbon dioxide laser or the like, or a YAG laser, and said
laser oscillating element is suitably selected in accordance with
various parameters such as the material of the container body and
the lid portion which undergo laser welding the laser irradiation
moving speed and the irradiation spot shape and the like. In the
case where a plastic container is laser welded, a semiconductor
laser (e.g., 1 W .about.100 W output) is preferred.
[0072] In the case where the sealed container 100 according to the
first embodiment is manufactured, after forming bonded surfaces by
bonding an outer wall surface of the peripheral portion of the
opening and an inner wall surface of the lid portion in order to
make it possible for at least an inner wall surface of the
peripheral portion of the opening from the inner wall surface of
the container body to make contact with the container contents, the
bonded surfaces are irradiated with a laser to form a welded
portion.
[0073] On the other hand, in the case where the sealed container
200 according to the second embodiment is manufactured, after
forming bonded surfaces by bonding an edge surface of the opening
and an inner wall surface of the lid portion in order to make it
possible for at least an inner wall surface of the peripheral
portion of the opening from the inner wall surface of the container
body to make contact with the container contents, the bonded
surfaces are irradiated with a laser to form a welded portion.
[0074] In this regard, a process which provides a laser light
absorbing portion in at least one of an outer wall surface of the
peripheral portion of the opening or an inner wall surface of the
lid portion, or in at least one of an edge surface of the opening
or an inner wall surface of the lid portion, is preferably
provided. Even if there are contours or undulations along the
absorbing portion which make mechanical contact complicated, laser
welding can be carried out with good precision. This is because the
laser light can focus on the irradiation spot, and the place
provided with the absorbing portion is mainly welded. The absorbing
portion can be formed by any method such as that where coloring is
carried out by bonding an absorbing material such as an organic
pigment or an inorganic pigment which absorb the wavelength of the
laser light to a prescribed connecting place. The wavelength of the
laser light, the laser power and the laser scanning speed are
preferably adjusted in accordance with the absorption degree of the
absorbing portion for the laser light. This process may be carried
out at any time before laser irradiation, and may be provided
before step S1, or in any one of step S1, step S2, step S3 or step
S4. Further, because this process is effective in the case where a
material that does not have an absorption band for the laser light
is welded, it is not an essential process.
[0075] Further, a laser light absorbing material may be included in
a portion of at least one of an outer wall surface of the
peripheral portion of the opening or an inner wall surface of the
lid portion, or in a portion of at least one of an end portion of
the opening or an inner wall surface of the lid portion. This
process may be carried out at any time before laser irradiation,
and may be provided before step S1, or in any one of step S1, step
S2, step S3 or step S4. For example, a laser absorbing material
such as a coloring pigment or the like is included in the case of
forming the lid portion and/or the container body. Further, because
this process is effective in the case where a material that does
not have an absorption band for the laser light is welded, it is
not an essential process in the case where the material absorbs the
laser light, such as the case that where a color container colored
by mixing a pigment or the like is laser welded or the like. In the
case where the connected portion absorbs laser light as in some of
the colored bottles, laser welding can be carried out just by
irradiation with the laser. Further, the wavelength of the laser
light, the laser power and the laser scanning speed are preferably
adjusted in accordance with the content of the laser absorbing
material such as a coloring pigment or the like.
[0076] Because the container body 61 and the lid portion 62 are
rotated by the rotation table 68, the laser irradiation portion
moves along the opening of the container body 61, and sealing is
finished by completing one cycle. The welding speed depends on the
shape and the material and the like to be connected, and is
8.about.50 cm/sec, for example. At this time, the places welded by
laser welding can be precisely controlled. Further, the output and
the wavelength of the laser determine the degree of fusion welding,
and a welded portion can be formed with better precision than heat
sealing or ultrasonic welding.
[0077] Further, laser irradiation may be carried out for two or
more cycles. By passing the laser spot several times, or having a
plurality of connected portions as shown in FIG. 2, it is possible
to carry out welding reliably. Further, laser welding in two or
more loop shapes may be carried out by providing two or more laser
oscillating elements and carrying out one cycle.
[0078] Next, in step S5, laser welding is finished and the sealed
container that was sealed is taken down from the turntable 69.
[0079] Next, in step S6, containers having sealing defects are
removed by defective container removing means 70. The judgment of
sealing defects is preferably carried out based on the monitoring
results described above and visual inspection results of an image
inspecting device (not shown in the drawings).
[0080] Next, a description will be given for the process (second
manufacturing embodiment) shown in FIG. 5. Because step S4 is
different in the process shown in FIG. 4 and the process shown in
FIG. 5, a description is given for step S4.
[0081] In step S4, the container body 61 with the lid 62 kept in
alignment is placed on a turntable 69. Each container body 61 and
the lid portion 62 thereof on the turntable 69 are at rest on the
turntable. At this time, a bonded portion 66 of the container body
61 and the lid portion 62 is irradiated with a laser by laser
generating means 65. Irradiation with the laser can be carried out
in a spot shape, a line shape or a ring shape, for example. The
laser irradiation shape is suitably selected by the positional
relationship between the laser generating means 65 and the bonded
portion 66. At this time, the laser intensity is preferably
monitored by monitoring the laser output. Further, the spot
position of the laser is preferably monitored by carrying out
monitoring in the same way as the case described in the process of
FIG. 4. The welding of plastic is also preferably monitored by
carrying out monitoring in the same way as the case described in
the process of FIG. 4. An imaging sensor such as a CCD or the like
may be used at the same time.
[0082] The same element as that described in the process of FIG. 4
can be used as the laser oscillating element installed in the laser
generating means 65.
[0083] In the case where the sealed container 100 according to the
first embodiment is manufactured, after forming bonded surfaces by
bonding an outer wall surface of the peripheral portion of the
opening and an inner wall surface of the lid portion in order to
make it possible for at least an inner wall surface of the
peripheral portion of the opening from the inner wall surface of
the container body to make contact with the container contents, the
bonded surfaces are irradiated with a laser to form a welded
portion.
[0084] On the other hand, in the case where the sealed container
200 according to the second embodiment is manufactured, after
forming bonded surfaces by bonding an edge surface of the opening
and an inner wall surface of the lid portion in order to make it
possible for at least an inner wall surface of the peripheral
portion of the opening from the inner wall surface of the container
body to make contact with the container contents, the bonded
surfaces are irradiated with a laser to form a welded portion.
[0085] In this regard, a process which provides a laser light
absorbing portion and/or a process to include a laser light
absorbing material are preferably provided in the same way as the
process described in FIG. 4.
[0086] Because the laser generating means 65 is rotated around the
container body 61 and the lid portion 62 by laser generator
rotating means 67, the laser irradiation portion moves along the
opening of the container body 61, and sealing is finished by having
the laser generating means 65 complete one cycle by the laser
generator rotating means 67. The welding speed depends on the shape
and the material and the like to be connected, and is 8.about.50
cm/sec, for example. At this time, the places welded by laser
welding can be precisely controlled.
[0087] Further, in the same way as in the case of FIG. 4, laser
irradiation may be carried out for two or more cycles. By passing
the laser spot several times, or having a plurality of connected
portions as shown in FIG. 2, it is possible to carry out welding
reliably. Further, laser welding in two or more loop shapes may be
carried out by providing two or more laser oscillating elements and
carrying out one cycle.
[0088] In the process shown in FIG. 5, because the laser
oscillating element is a rotary type which rotates around the
container, high-speed movement and laser welding at a plurality of
connected places (simultaneous timing or separate timing,
irradiation at the same place or irradiation at separate places)
becomes possible.
[0089] In the prior art seaming process for metal cans, it is
difficult to judge whether or not a container is properly sealed at
the point in time when the seaming process is actually carried out.
For this reason, regardless of there being good inspection results
before the start of manufacturing, in the case where sealing
defects occur in the seaming process, defect detection is found out
after a passage of time from the actual defect occurrence. In this
case, the number of containers that need to be discarded and the
stopping time of the industrial apparatus become very large. On the
other hand, in accordance with the method of manufacturing a sealed
container shown in FIG. 4 or FIG. 5 according to the present
embodiment, because it is possible to detect in a very short time
whether or not the welding process was carried out properly, the
disadvantages described above in the seaming process for metal cans
do not occur.
* * * * *