U.S. patent number RE33,880 [Application Number 07/505,347] was granted by the patent office on 1992-04-14 for pouch or sack for packing and laminate film therefor and method for producing the pouch.
This patent grant is currently assigned to Kabushiki Kaisha Hosokawa Yoko. Invention is credited to Yoshiji Moteki, Shigeyuki Oshima, Shokichi Yamazaki.
United States Patent |
RE33,880 |
Yamazaki , et al. |
April 14, 1992 |
Pouch or sack for packing and laminate film therefor and method for
producing the pouch
Abstract
Disclosed are a pouch for containing a material therein, a
laminate film for the pouch, and a method for producing the pouch.
The laminate film comprises a first plastic layer and at least one
second plastic layer on which said first plastic layer is
laminated. The first plastic layer is partially subjected to
surface roughening treatment prior to the lamination, and surface
irregularities are filled with a plastic material of the second
plastic layer. In a pouch having substantially rectangular shape,
at least one folded portion is provided at a side edge of the
pouch. The surface roughened portion is positioned at and around
the folded portion and at an external surface of the pouch. In one
embodiment, the folded edge is provided at one side of the pouch
and a heat sealed portion is provided at the other side edge
thereof. In another embodiment, folded portions are provided at
both side edges of the pouch and a heat-sealed portion is provided
at a rear central portion thereof.
Inventors: |
Yamazaki; Shokichi (Hanno,
JP), Oshima; Shigeyuki (Tokyo, JP), Moteki;
Yoshiji (Kitaadachi, JP) |
Assignee: |
Kabushiki Kaisha Hosokawa Yoko
(JP)
|
Family
ID: |
27290596 |
Appl.
No.: |
07/505,347 |
Filed: |
April 5, 1990 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
98880 |
Sep 21, 1987 |
04778058 |
Oct 18, 1988 |
|
|
Foreign Application Priority Data
|
|
|
|
|
Mar 19, 1987 [JP] |
|
|
62-40773 |
Jul 31, 1987 [JP] |
|
|
62-192071 |
Sep 8, 1987 [JP] |
|
|
62-136872 |
|
Current U.S.
Class: |
383/200; 206/484;
428/43; 493/199; 493/223; 493/228; 53/133.1; 53/141 |
Current CPC
Class: |
B32B
27/08 (20130101); B65D 33/02 (20130101); B65D
31/02 (20130101); Y10T 428/15 (20150115) |
Current International
Class: |
B32B
27/08 (20060101); B65D 30/08 (20060101); B65D
33/02 (20060101); B65D 005/59 () |
Field of
Search: |
;206/484,610,611,620,632,604 ;383/103,109 ;156/153,257 ;428/43,910
;53/133,141,142 ;493/199-201,223,228 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
711603 |
|
Jun 1965 |
|
CA |
|
2909276 |
|
Sep 1980 |
|
DE |
|
0032981 |
|
Mar 1977 |
|
JP |
|
54-22484 |
|
Aug 1979 |
|
JP |
|
55-39196 |
|
Oct 1980 |
|
JP |
|
58-13680 |
|
Jan 1983 |
|
JP |
|
61-142133 |
|
Jun 1986 |
|
JP |
|
61-142159 |
|
Jun 1986 |
|
JP |
|
62-52065 |
|
Mar 1987 |
|
JP |
|
2035258 |
|
Jun 1980 |
|
GB |
|
Primary Examiner: Gehman; Bryon P.
Attorney, Agent or Firm: Oliff & Berridge
Claims
What is claimed is:
1. A laminate film .[.for.]. pouch comprising:
an external plastic layer; and.[.,.].
at least one internal plastic layer on which said external plastic
layer is laminated; said external plastic layer being formed with a
surface roughened portion at a .Iadd.non-heat-sealed
.Iaddend.position .[.corresponding to a folded portion of a
resultant.]. .Iadd.crossing a fold line of the .Iaddend.pouch.
2. The laminate film .Iadd.pouch .Iaddend.as claimed in claim 1,
wherein said external plastic layer comprises .[.polypropyrene.].
.Iadd.polypropylene .Iaddend.film.
3. The laminate film .Iadd.pouch .Iaddend.as claimed in claim 2,
wherein said .[.polypropyrene.]. .Iadd.polypropylene .Iaddend.film
is a single axial stretching film.
4. The laminate film .Iadd.pouch .Iaddend.as claimed in claim 1,
wherein said external plastic layer comprises polyester film.
5. The laminate film .Iadd.pouch .Iaddend.as claimed in claim 1,
wherein said internal plastic layer comprises polyethylene
film.
6. The laminate film .Iadd.pouch .Iaddend.as claimed in claim 4,
further comprising an aluminum foil laminated with said internal
plastic layer, and a plastic film laminated with said aluminum
foil.
7. The laminate film .Iadd.pouch .Iaddend.as claimed in claim 1,
wherein said surface roughened portion .[.has.]. .Iadd.forms a
.Iaddend.continuous meandered .[.arrangement, said meandered
portion.]. .Iadd.line .Iaddend.having a small width, and .Iadd.a
large .Iaddend.resultant .[.surface roughened portion having a
wide.]. .Iadd.meandered .Iaddend.width extending .[.over said
folded portion.]. .Iadd.across said fold line.Iaddend..
8. The laminate film .Iadd.pouch .Iaddend.as claimed in claim 1,
wherein said surface roughened portion is formed with a plurality
of circular recesses arranged in groups of rows, said groups being
directed in parallel with each other and extending obliquely with
respect to .[.a folded line of.]. said .[.folded portion.].
.Iadd.fold line.Iaddend..
9. The laminate film .Iadd.pouch .Iaddend.as claimed in claim 1,
wherein said surface roughened portion is formed with .[.a.].
surface .[.irregularlities.]. .Iadd.irregularities .Iaddend.into
which a material of said internal plastic layer is filled.
10. A pouch comprising: a laminated film defining a rectangular
pouch body; said laminated film comprising an external plastic
layer and an internal plastic layer, said laminated film being
formed with at least one folded portion .Iadd.containing a fold
line.Iaddend., and a heat-sealed portion connecting free ends of
said laminated film, .Iadd.a non-heat-sealed area of .Iaddend.said
folded portion being formed with a surface roughened portion which
.Iadd.crosses said fold line and .Iaddend.is formed at the external
side of said pouch.
11. The pouch as claimed in claim 10, wherein said folded portion
.[.is positioned at.]. .Iadd.form .Iaddend.one side edge portion of
said pouch, and said heat-sealed portion .[.is positioned at the
other.]. .Iadd.forms another .Iaddend.side edge portion
thereof.
12. The pouch as claimed in claim 10, wherein two folded portions
.[.are provided at both.]. .Iadd.form two .Iaddend.side edge
portions of said pouch, said heat-sealed portion projecting
outwardly at a rear portion of said pouch.
13. The pouch as claimed in claim 12, further comprising a second
surface roughened portion at a folded portion of said heat-sealed
portion.
14. The pouch as claimed in claim 10, wherein each of .Iadd.two
.Iaddend.side edge portions of said pouch comprises three folding
lines to provide two ridge portions and one valley portion
positioned between said two ridge portions, one of the side edge
portions being formed with said surface roughened portions at said
ridge portions, and the other side edge portion being formed with
said surface roughened portion at said valley portion.
15. The pouch as claimed in claim 14, wherein said heat-sealed
portion projects outwardly from a rear portion of said pouch, and a
second surface roughened portion is provided at and around a folded
line of said heat-sealed portion.
16. The pouch as claimed in claim 10, wherein said external plastic
layer comprises .[.polypropyrene.]. .Iadd.polypropylene
.Iaddend.film.
17. The pouch as claimed in claim 16, wherein said
.[.polypropyrene.]. .Iadd.polypropylene .Iaddend.film is a single
axial stretching film.
18. The pouch as claimed in claim 10, wherein said external plastic
layer comprises polyester film.
19. The pouch as claimed in claim 10, wherein said internal plastic
layer comprises polyester film.
20. The pouch as claimed in claim 18, further comprising an
aluminum foil laminated with said internal plastic layer, and a
plastic film laminated with said aluminum foil.
21. The pouch as claimed in claim 10, wherein said surface
roughened portion .[.has.]. .Iadd.forms a .Iaddend.continuous
meandered .[.arrangement, said meandered portion.]. .Iadd.line
.Iaddend.having a small width, and .Iadd.a large .Iaddend.resultant
.[.surface roughened portion having a wide.]. .Iadd.meandered
.Iaddend.width extending .[.over said folded portion.].
.Iadd.across said fold line .Iaddend..
22. The pouch as claimed in claim 10, wherein said surface
roughened portion is formed with a plurality of circular recesses
arranged in groups of rows, said groups being directed in parallel
with each other and extending obliquely with respect to .[.a folded
line of.]. said .[.folded portion.]. .Iadd.fold line.Iaddend..
23. The pouch as claimed in claim 10, wherein said surface
roughened portion is formed with .[.a.]. surface
.[.irregularlities.]. .Iadd.irregularities .Iaddend.into which a
material of said internal plastic layer is filled.
24. A method for producing a pouch comprising the steps of:
preparing a rectangular first plastic film web and at least one
rectangular second plastic film web;
roughening partial surface portions of .[.a.]. one surface of said
first plastic film web, said partial portions .[.corresponding to
folded portions.]. .Iadd.crossing a non-heat-sealed portion of said
web corresponding to at least one fold line .Iaddend.of said
pouch;
laminating together said first and second plastic film webs to
provide a composite film;
cutting said composite film into rectangular segments;
folding said rectangular .[.segment,.]. .Iadd.segments along said
fold line; .Iaddend.and
heat-sealing free ends of said rectangular .[.segment.].
.Iadd.segments.Iaddend..
25. The method as claimed in claim 24, wherein .[.said.]. .Iadd.the
.Iaddend.roughening step is performed by pressing a rigid
roughening member onto said one surface of said first plastic film
web.
26. The method as claimed in claim 24, wherein said roughening step
is performed by applying one of laser beam, corona discharge,
plasma discharge and ultrasonic wave onto parts of said first
plastic film web.
27. The method as claimed in claim 24, further comprising the step
of printing the other surface of .[.said.]. .Iadd.the
.Iaddend.first plastic film web prior to said roughening step.
.Iadd.
28. The laminate film pouch as claimed in claim 1, wherein said
surface roughened portion is formed at a portion of the pouch
between two opposite heat sealed edges of the pouch. .Iaddend.
.Iadd.29. The pouch as claimed in claim 10, wherein said surface
roughened portion is formed at a portion of the pouch between two
opposite heat sealed edges of the pouch. .Iadd.30. The method as
claimed in claim 24, wherein said partial surface portions are
roughened at a portion of said web corresponding to a portion of
the pouch between said heat sealed free ends of said rectangular
segments. .Iaddend. .Iadd.31. A pouch comprising:
a pouch body formed of a laminate sheet including at least two
layers of material, the laminate sheet comprising:
a first layer formed of a plastic material and being provided with
a tear facilitating surface roughened portion comprising surface
irregularities;
a second layer laminated to the first plastic layer; and
filling material at least partially filling the surface
irregularities;
wherein the tear facilitating surface roughened portion forms a
guide line extending across a non-heat-sealed portion of the pouch
body for tearing
the pouch body along the guide line. .Iaddend. .Iadd.32. The pouch
as claimed in claim 31, wherein said first layer is an exterior
layer of said pouch. .Iaddend. .Iadd.33. The pouch as claimed in
claim 31, wherein the filling material comprises a resin. .Iaddend.
.Iadd.34. The pouch as claimed in claim 31, wherein the second
layer is formed of a plastic material and wherein the filling
material is the same as the plastic material of the second layer.
.Iaddend. .Iadd.35. The pouch as claimed in claim 34, wherein the
filling material is material flowed from the second layer into the
surface irregularities during lamination of the first and second
layers. .Iaddend. .Iadd.36. The pouch as claimed in claim 31,
wherein said surface irregularities comprise a plurality of scores
or
scratches. .Iaddend. .Iadd.37. A pouch comprising:
a pouch body formed of a laminate sheet including at least two
layers of material, the laminate sheet comprising:
a first layer formed of a plastic material and being provided with
a tear facilitating surface roughened portion comprising surface
irregularities;
a second layer laminated to the first plastic layer; and
filling material at least partially filling the surface
irregularities;
wherein said surface roughened portion has a continuous meandered
arrangement extending across a non-heat-sealed portion of the pouch
body and providing a resultant surface roughened portion of
relatively large
width. .Iaddend. .Iadd.38. A pouch comprising:
a pouch body formed of a laminate sheet including at least two
layers of material, the laminate sheet comprising:
a first layer formed of a plastic material and being provided with
a tear facilitating surface roughened portion comprising surface
irregularities;
a second layer laminated to the first plastic layer; and
filling material at least partially filling the surface
irregularities;
wherein said surface roughened portion is formed of a plurality of
circular rough surface portions arranged in a plurality of rows
directed parallel to each other and obliquely to an edge of the
pouch and extending across a
non-heat-sealed portion of the pouch body. .Iadd.39. A sheet
product comprising at least one plastic sheet having a tear
facilitating surface roughened portion, said surface roughened
portion comprising a group of densely formed and randomly oriented
surface irregularities, said group being in the form of a
continuous meandered arrangement providing a resultant surface
roughened portion of relatively large width. .Iaddend.
.Iadd.40. The sheet product claimed in claim 39, wherein said sheet
product is a sealed pouch. .Iaddend. .Iadd.41. A sheet producing
comprising at least one plastic sheet having a tear facilitating
surface roughened portion, said surface roughened portion being
formed of a plurality of circular rough surface portions, each
containing densely formed and randomly oriented surface
irregularities, arranged in a plurality of rows directed parallel
to each other and obliquely to an edge of the product. .Iaddend.
.Iadd.42. A sheet product as claimed in claim 41, wherein said
sheet product is a sealed pouch. .Iaddend.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a sack or pouch for packing a
material therein and to a laminate film for the sack, and more
particularly, to the sack and the laminate film which is easily
tearable yet having sufficient fracture strength and
sealability.
The present invention also relates to a method for producing such
sack or pouch and for producing the laminate film therefor.
A composite film is generally available as a material of a sack or
pouch. The composite film includes a polyethylene film laminated on
an ordinary cellophane sheet or paper. When the pouch or the sack
formed of the laminated film is required to be opened, a
heat-sealed portion of the pouch can be manually torn, i.e., a user
can .[.manurally.]. .Iadd.manually .Iaddend.break the seal at the
heat-sealed portion. Therefore, such type of pouch is widely
available. However, the composite film does not provide sufficient
fracture strength and fluid-tightness particularly against
moisture. Accordingly, a content to be packed is subjected to
limination.
In order to overcome these drawbacks, a plastic laminated film is
used as a material of the sack or pouch so as to improve fracture
strength and moisture resistivity. However, the plastic laminated
film provides relatively high tearing strength, so that it would be
rather difficult to manually tear a pouch open at its sealing
portion. Therefore, a cutter or other jig must be used to open the
pouch.
In case of the pouch formed of the above-described plastic
laminated film, demand has been made for manually .[.open.].
.Iadd.opening .Iaddend.the pouch at its heat-sealed portion. To
meet with the demand, V-shaped or I-shaped notch is formed at the
heat-seal portion. Such notches serve to concentrate tearing force
thereat and to propergate the force along the tearing
direction.
Such notches can be easily formed by the lamination film
manufacturer prior to filling a content in the package or pouch.
However, if the film manufacturer simply supplies a rolled
lamination film to the lamination film users, it would be rather
difficult for the users to form such notch at the heat-sealed
portion of the pouch during pouch production and content packing
processes.
Japanese Patent Publication 61-39228 discloses a pouch 1 in which a
heat-sealed portion 2 is subjected to a plurality of minute scoring
or scratching 3 without formation of V-shaped notch as shown in
FIG. 1. These scratches 3 are formed to a sheet prior to the
production of the pouch, i.e., prior to the heat-seal process.
Alternatively, after .Iadd.a .Iaddend.heat-sealed process, these
scratches are formed at the heat-sealed portion 2.
In this case, it would be rather difficult to form the scratches at
a sheet web so as to correctly align the scored or scratched
portion with the heat sealed portion in a subsequent heat-seal
process. On the other hand, during heat-seal process, it would be
also difficult and time-consuming to form scratches at the
heat-sealed portion.
SUMMARY OF THE INVENTION
It is therefore, an object of the present invention to overcome the
above-described disadvantages and to provide an improved laminated
film and a pouch which uses the laminated film.
Another object of this invention is to .[.provede.]. .Iadd.provide
.Iaddend.an improved method for producing such pouch.
Still another object of this invention is to provide such pouch or
sack which is easily tearable yet having sufficient fracture
strength, moisture resistivity and fluid-tightness.
Still another object of this invention is to provide such laminated
film and a pouch which uses the laminated film having excellent
outer appearance without any formation of notches.
Still another object of this invention is to provide the pouch
which has a tearable portion at a position other than a heat-sealed
portion.
These and other object of the present invention are attained by
providing a manually tearable portion at a foled portion of a sack
or pouch. A composite laminate film is used as a material of the
pouch. The composite laminate film includes at least two films, and
is subjected to surface roughening at an area corresponding to the
folded portion. The roughening portion is formed only in one of the
films, and the roughened surface is positioned at an external side
of the pouch. The composite laminate film web having rectangular
shape is heat-sealed together at both end portions, so that
cylindrical member is provided. The cylindrical member is folded to
obtain flat rectangular shape, and at least one end corresponding
to a bottom or top portion of the pouch is also heat-sealed. As a
result, there are at least one folded portion at one side of the
pouch, one heat-sealed portion and at least one heat-sealed portion
at a bottom of the pouch. The folded portion includes the
above-mentioned surface roughened portion.
The roughened portion serves as an initial start-up of the tearing
operation of the pouch. Further, minute bores or voids in the
roughened portion .[.is.]. .Iadd.are .Iaddend.impregnated with
other material which is a material of another film of the composite
film. Therefore, external surface of the pouch provides a flat
surface without any notch nor scratch, so that excellent outer
appearance results at the tearing portion.
The roughened portion may linearly .[.extends.]. .Iadd.extend
.Iaddend.in the composite film. Preferrably, the roughened portion
may be meandered or lain in a zig-zag line. Alternatively, spot
like dimples are discontinuously formed to provide the
.[.roughned.]. .Iadd.roughened .Iaddend.zone. The meandering and
discontinuous formation can enlarge substantial width of the
roughened zone at a position corresponding to the folded portion of
the pouch.
The surface roughening treatment is performed prior to .Iadd.a
.Iaddend.heat-seal process, and at a position other than the
heat-sealed portion. The roughened portion is provided by forcibly
pressing the running web-like plastic film against a rough surface
member (direct contact method). Alternatively, the plastic film is
subjected to surface roughening by the application of laser beam,
corona discharge, plasma discharge, etc (non-contact method).
.[.Thus.]. .Iadd.The thus .Iaddend.treated plastic film is
laminated onto substrate film to provide a composite film web.
Thereafter, the web is cut to a predetermined length so as to align
the roughened portion with the folded portion of the pouch, and
then the .[.cutted.]. .Iadd.cut .Iaddend.composite film is folded
and heat-sealed. The lamination is carried out by extruding the
films. During the extrusion process, the substrate material is
entered into bores or minute voids of the plastic film, so that
external surface of the plastic film becomes flat, yet the
roughened plastic film functions as .[.an.]. .Iadd.a
.Iaddend.propellant for tearing or breaking action of the folded
portion of the pouch.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a perspective view showing a conventional pouch or sack
for packing a content therein;
FIG. 2 is a cross-sectional view of a composite laminate film
according to a first embodiment of the .[.prsent.]. .Iadd.present
.Iaddend.invention;
FIG. 3 is a cross-sectional view of a composite laminate film
subjected to surface roughening according to the first
embodiment;
FIG. 4 is a cross-sectional view showing a composite laminate film
according to a second embodiment of this invention;
FIG. 5(a) is a perspective view showing a pouch according to a
first embodiment of the present invention;
FIG. 5(b) is a cross-sectional view taken along the line V--V of
FIG. 5(a);
FIG. 6(a) is a perspective view showing a pouch according to a
second embodiment of the present invention;
FIG. 6(b) is a cross-sectional view taken along the line VI--VI of
FIG. 6(a);
FIG. 7 is an exploded view of FIG. 6(a);
FIG. 8(a) is a perspective view showing a pouch according to a
third embodiment of this invention;
FIG. 8(b) is a cross-sectional view taken along the line VIII--VIII
of FIG. 8(a);
FIGS. 9 and 10 show configurations of roughened areas according to
this invention;
FIG. 11 is a perspective view showing a modified embodiment
according to the present invention;
FIG. 12 is a block diagram showing a process for producing a pouch
for packing .[.purpose.]. .Iadd.purposes .Iaddend.according to this
invention; and,
FIG. 13 is a schematic illustration showing a device for forming
.Iadd.a .Iaddend.roughening zone to a plastic film prior to its
.[.laminataion.]. .Iadd.lamination .Iaddend.onto a substrate.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A plastic laminate film 6 according to a first embodiment is shown
in FIG. 2. The plastic laminate film includes a polyethylene film 8
having a thickness of 40 microns and a polypropylene film 7 having
a thickness of 20 microns laminated onto the film 8. The
polypropylene film 7 is subjected to biaxial stretching.
Alternatively, a single axial high stretching is preferrable if
linear opening or tearing is desired.
As shown in FIG. 3, a roughened surface 10 is formed at the
polypropylene film 7. The roughened surface 10 is positioned at
.Iadd.an .Iaddend.external side of a resultant pouch shown, for
example, in FIG. 5(a), and at a folded portion 5 thereof. This
roughened surface 10 serves to easily tear the pouch open.
Prior to the extrusion-lamination of the polypropylene film 7 onto
the polyethylene film 8, the polypropylene film 7 is subjected to
surface roughening treatment, so that scored or scratch portions 9
are formed on the film 7 as shown in FIG. 3. These bores or holes
or dimples at the scored portions are filled with polyethylene
material during subsequent lamination process. Therefore, the outer
surface of the polypropylene film 7 becomes .Iadd.a .Iaddend.flat
surface.
More specifically, FIG. 13 shows roughened surface forming machine
66 in which .Iadd.is .Iaddend.disposed .[.are.]. a metal roller 67
and a rough surface forming roller 68, and the polypropylene film 7
travels between the rollers. Over the rough surface forming roller
68, a sand paper or emery paper 69 is provided. The running film 7
is formed with the scores or scratches 9 by the urging force of the
sandpaper 69. The sandpaper has a particle size degree of No. 100
(defined by Japanese Industrial Standard JIS R-6001 which
substantially corresponds to ANSI B 74.18 FEPA 30GB). .Iadd.The
sandpaper or emery paper inherently creates densely formed and
randomly oriented surface irregularities. .Iaddend.
Since the roughened surface 10 is positioned at .Iadd.an
.Iaddend.external side of the pouch and at a folded portion
thereof, the pouch is easily opened manually without any heavy
manual force nor cutting means.
A pouch 1 formed of the lamination sheet 6 is shown in FIGS. 5(a)
and 5(b). The pouch 1 has two heat-sealed portions, i.e., a side
seal 2 and a bottom seal 4. Of course, an open top portion is also
heat-sealed after a content is filled in the pouch. In the pouch 1,
there is a single folded portion 5, and the surface roughened
portion 10 is provided at the folded portion 5 only. As shown in
FIG. 5(b), the surface roughened portion 10 is positioned at an
external side of the pouch 1. Therefore, the content in the pouch 1
is in contact with the polyethylene film 8.
FIGS. 6(a) .[.throu.]. .Iadd.through .Iaddend.7 show a pouch 1A
according to a second embodiment of the present invention. The
pouch 1A is of pillow bag type in which there are two side folded
portions 5a and 5b and a central heat sealed portion 2a at a rear
surface of the bag 1A. As best shown in FIG. 7, the rear
heat-sealed portion 2a is provided at both longitudinal end
portions of the laminated film web 6. The rear-heat sealed portion
2a is defined by folding lines 27 and 28, and roughened surface
area 10b is provided at and around the one of the folding lines 28.
The pillow type pouch 1A has two side edges 29 and 30 which are
defined by folding lines 29a and 30a. Further, another roughened
surface area 10a is provided at and around one of the .[.foding.].
.Iadd.folding .Iaddend.lines 29a which is positioned around one of
the folding lines 29a which is positioned spaced away from the
folding line 28 in comparison with the other folding line 30a. As
shown in FIG. 6(a), the pouch 1A is opened from the side folded
line 29 on which the surface roughened portion 10a is provided.
Further, the other surface roughened portion 10b is provided at the
heat sealed portion 2a-1 which is positioned .[.farer.].
.Iadd.further .Iaddend.than the confronting heat sealed portion 2a
with respect to the side edge line 29. Therefore, the linear
opening or tearing operation is smoothly carried out even at the
rear central heat sealed portion 2a-1. As best shown in FIG. 6(b),
the surface roughened portions 10a and 10b are positioned at
.Iadd.an .Iaddend.outside or external surface of the pouch 1A. Of
course, upper and lower open ends of the pillow type 1A are also
heat sealed, and the rear central heat sealed portion 2a projects
outside of the pillow.
FIGS. 8(a) to 8(b) show a gazette type pouch 1B in which each of
the side portions is folded into M-shape in cross-section as best
shown in FIG. 8(b). This type of pouch 1B is particularly available
for containing therein .Iadd.a .Iaddend.large amount of content,
and for providing self-upstanding function. In FIG. 8(a), assuming
that the pouch is opened from a direction shown by an arrow,
surface roughened portions 31a and 32a are provided at and around
two ridge portions 31 and 32 those positioned at one of the gazette
portions 30a. Another surface roughened portion 33a is provided at
and around a valley portion of the other gazette portion 30b.
Further, a rear central sealing portion 2b projects outside of the
pouch 1B, and a surface roughened portion 34a is provided at and
around one of the folding line 34 of the sealing portion 2b. These
surface roughened portions 31a,32a, 33a and 34a are positioned at
.Iadd.an .Iaddend.external side of the pouch 1A as shown in FIG.
8(b). The folding line 34 is positioned .[.farer.]. .Iadd.further
.Iaddend.than a .[.folidng.]. .Iadd.folding .Iaddend.line 35 with
respect to the tearing starting edges 31 and 32. Of course, upper
and lower open ends are also heat sealed.
FIG. 11 show a cylindrical packing bag 41 applicable for packing a
sausage. In this case, surface roughened portion 40 for opening
purpose is spirally arranged .Iadd.to form a guide line extending
across a non-heat-sealed portion of the pouch body for tearing the
pouch body along the guide line. .Iaddend.Therefore, the package 41
can be successively removed in accordance with the user's
demand.
FIG. 4 shows a cross-sectional view of a composite laminate film 6a
according to a second embodiment of this invention. The composite
laminate film 6a includes a polyester film 52 having a thickness of
12 microns, a polyethylene film 53 having a thickness of 15
microns, an aluminum foil 54 having a thickness of 7 microns, and
polyethylene film 55 having a thickness of 30 microns. A surface of
the polyester film 52 is formed with a surface roughened portion
10a which is produced in a manner the same as that in the first
embodiment shown in FIG. 3. The composite laminate film 6a is also
available for the pouches or sacks shown in FIGS. 5(a)-5(b), FIGS.
6(a)-7, FIGS. 8(a)-8(b), and FIG. 11.
FIGS. 9 and 10 show modifications of the surface roughened zones.
In an embodiment shown in FIG. 9, surface roughened zone 10c
.[.is.]. .Iadd.comprises a group of densely formed and randomly
oriented surface irregularities, .Iaddend.meandered or lain in a
zig-zag line. The surface roughened zone 10c is provided at, for
example, the polyester film 52 shown in FIG. 4. Even though the
meandered line has a small width h, resultant meandered width H
becomes large, so that the surface roughened zone can surely
.[.occupies.]. .Iadd.occupy .Iaddend.an area at and adjacent the
folded line L. As described above, in the present invention, the
surface roughening treatment is carried out on the laminated film
web, prior to heat-sealing operation for making the pouch.
Therefore, substantial increase in width H of the surface
.[.roghened.]. .Iadd.roughened .Iaddend.zone has advantages in that
the zone can surely be positioned at the folded line and a portion
adjacent thereto.
The same is true with respect to an embodiment shown in FIG. 10. In
this embodiment, a plurality of circular rough surface portions 10c
are arranged in a plurality of rows, each rows being directed in
parallel and oblique with respect to the folding line L at an angle
of 45 degrees. .Iadd.As may be seen in FIG. 10, each circular rough
surface portion 10c contains densely formed and randomly oriented
surface irregularities. .Iaddend.
Because of the continuous meandered rough surface zone 10c (FIG. 9)
and discontinuous and obliquely arranged rough surface zone 10d
(FIG. 10), substantial width of the roughened portion can be
increased to H or H'. Therefore, the roughened portion can be
positioned without fail at and adjacent the folded line L. Such
arrangement can minimize roughened treatment area. Therefore,
resultant pouch can provide improved mechanical strength and gas
barrier characteristics, yet providing easy tearing at the folded
portion positioned at at least one of the side edges of the
pouch.
In view of the foregoing, according to the pouch of this invention,
.Iadd.a .Iaddend.surface roughened portion is provided at the
folded portion of the pouch disposed at at least one of the side
edges thereof, .[.and.]. the surface roughened portion is
positioned at the external side of the pouch, .Iadd.and
.Iaddend.the pouch is easily opened with small manual force.
Further, even by the formation of the surface roughened portion,
the surface .[.irreguralities is.]. .Iadd.filled with the
irregularities are .Iaddend. other plastic material, so that
excellent sealability is obtainable with excellent outer
appearance. Accordingly, the external surface of the pouch is
available for sufficient printing regardless of the folded
portion.
Next a method of producing such laminated film and a method for
producing such pouch will be described with reference to FIG. 12.
The following description will be premised on the composite film
shown in FIG. 4. First, row material film webs are prepared such as
polyester film 52 having a thickness of 12 microns, aluminum foil
54 having a thickness of 7 microns, and polyethylene film 53 having
a thickness of 15 microns. The polyester film 52 has one surface
subjected to printing, and the other surface subjected to surface
roughening by the method shown in FIG. 13. Thereafter, these films
and a polyethylene film 55 having a thickness of 30 microns are
extrusion-laminated together. By this lamination process, the
surface irregularities formed at the surface roughening step
.[.is.]. .Iadd.are .Iaddend.filled with polyethylene material of
the polyethylene film 53. In the surface roughening step, instead
of the .[.emplyment.]. .Iadd.employment .Iaddend.of the sand-paper,
.Iadd.a .Iaddend.laser beam is used to provide a plurality of
perforations or to provide linear recesses. Alternatively, corona
discharge, plasma discharge and .[.untrasonic.]. .Iadd.ultrasonic
.Iaddend.wave are also available for forming the surface
irregularities.
The surface roughening is carried out so as to provide the surface
roughened zones having a predetermined width by a given intervals
corresponding to the size and shape of the pouch.
Thus prepared laminated film 6a is subjected to cutting or
slitting, and thereafter, each of the cut segments is folded and
heat-sealed. In this case, there are surface roughened zone at the
folded portion, i.e., at least one of the side edges of the pouch.
If desired, additional surface roughened zone is provided whose
position corresponds to the rear central folded portion of the
pouch. Of course, this additional surface roughened zone is
provided prior to the lamination step.
While the invention has been described in detail and with reference
to specific embodiments thereof, it will be apparent for those
skilled in the art that various changes and modifications can be
made therein without departing from the spirit and scope of the
invention.
* * * * *