Note: Descriptions are shown in the official language in which they were submitted.
CA 02832856 2013-11-08
Plastic Film Joining Method
Technical Field
The invention relates to a plastic film joining method.
Background
For example, Japanese Laid¨Open Patent Publication No. 2007-238129
discloses a plastic bag used as an internal bag received in a bag in box. In
the
internal bag, a composite film is composed of external and internal films
opposed
to and superposed with each other, to have opposite end portions. The internal
bag includes two of the composite films opposed to and superposed with each
other. A process is then performed to join all the films with each other at
the
opposite end portions so that first joining portions should be formed between
the
external and internal films, a second joining portion being formed between the
internal films, to make the plastic bag which is used as the internal bag. The
external and internal films comprise plastic films.
In this case, the external and internal films are subjected to an impact
load when dropping the internal bag so that a stress must be concentrated on
the
second joining portion formed between the internal films. The internal films
may
therefore be peeled and separated off from each other at the second joining
portion, resulting in break of the internal bag.
The same is true of the internal bag received in the bag in box of
Japanese Laid¨Open Patent Publication No. 2011-235933 and Japanese Patent
Publication No. 3324953.
By the way, it is usual when joining all the films with each other that a
heater is pressed against the external and internal films to heat seal and
join all
the films with each other. In addition, it is practicable to irradiate
laser¨beam
between and onto the external and internal films, welding and joining all the
films
with each other. See Japanese Laid¨Open Patent Publication No. 2009-255461,
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Japanese Patent Publication No. 4404288. Japanese Laid¨Open Patent
Publication No. S60-157842 and Japanese Patent Publication No. 4104073.
A handle may be formed of the composite film composed of the external
and internal films.
It is therefore an object of the invention to provide a plastic film joining
method, which can keep the plastic films from being peeled off from each other
at
a concerned joining portion.
Summary of the Invention
According to the invention, a composite film is composed of external and
internal films opposed to and superposed with each other, to have opposite end
portions. The composite film is opposed to and superposed with an additional
body. The method include joining the external and internal films and the
additional body with each other at one of the end portions so that a first
joining
portion should be formed between the external and internal films, a second
joining portion being formed between the internal film and the additional
body.
The first joining portion has a first joining width and includes first outer
and inner
edges formed by the first joining width. The second joining portion has a
second
joining width and includes second outer and inner edges formed by the second
joining width. The method comprises making an adjustment of the first or
second joining width, the first joining width being less than the second
joining
width so that the first inner edge should be formed outwardly of the second
inner
edge.
In a preferred embodiment, making the adjustment comprises preparing
first and second heaters for the first and second joining portions. Making the
adjustment further comprises making the internal film superposed with the
additional body, the second heater being pressed against the internal film and
the
additional body to heat seal and join the internal film and the additional
body with
each other and make the second joining portion formed. The second heater has
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an effective width predetermined for adjustment of the second joining width.
Making the adjustment further comprises then making the external film
superposed with the internal film, the first heater being pressed against the
external and internal films and the additional body to heat seal and join the
external and internal films with each other and make the first joining portion
formed. The first heater has an effective width predetermined for adjustment
of
the first joining width.
In another embodiment, making the adjustment comprises preparing a
heater for the first and second joining portions. Making the adjustment
further
comprises making a coating of anti¨adhesive agent formed between the external
and internal films when the external and internal films and the additional
body are
superposed with each other. Making the adjustment further comprises then
making the heater pressed against the external and internal films and the
additional body to heat seal and join the external and internal films and the
additional body with each other and make the first and second joining portions
formed. The coating of anti¨adhesive agent is disposed at a position and in a
range predetermined for adjustment of the first joining width.
In another embodiment, making the adjustment comprises preparing a
first irradiator for irradiating laser¨beam between and onto the external and
internal films. Making the adjustment further comprises preparing a first
scanning device connected to the first irradiator to move the first irradiator
in
opposite directions so that the external and internal films should be scanned
with
the first irradiator, welding and joining the external and internal films with
each
other. Making the adjustment further comprises preparing a second irradiator
for irradiating laser¨beam between and onto the internal film and the
additional
body. Making the adjustment further comprises a second scanning device
connected to the second irradiator to move the: second irradiator in the
opposite
directions so that the internal film and the additional body should be scanned
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with the second irradiator, welding and joining the internal film and the
additional
body with the each other. Making the adjustment further comprises preparing a
control device connected to the first and second irradiators and the first and
second scanning devices to control the first and second irradiators and the
first
and second scanning devices individually for adjustment of the first and
second
joining widths.
In another embodiment, making the adjustment comprises preparing an
irradiator opposed to the external and internal films and the additional body
superposed with each other to irradiate laser¨beam onto the external and
internal
films and the additional body. Making the adjustment further comprises making
treatments of laser absorption applied between the external and internal films
and the additional body to weld and join the external and internal films and
the
additional body with each other by irradiating the laser¨beam. The treatments
of laser absorption are disposed at positions and in ranges predetermined for
adjustments of the first and second joining widths.
An intermediate film may be interposed between the external and internal
films. The method includes joining the external, intermediate and internal
films
with each other. The first joining portion comprises a plurality of joining
portions. The first joining width comprises a plurality of joining widths. The
first inner edge comprises a plurality of inner edges. The plurality of
joining
widths are predetermined to be less in stages. The plurality of inner edges
are
formed outwardly in stages.
The additional body may comprise a composite film composed of external
and internal films opposed to and superposed with each other, to have opposite
end portions. The method includes joining all the films with each other at the
opposite end portions of the composite films to make a plastic bag.
The additional body may comprise the other end portion of the composite
film. The composite film is bent to have the opposite end portions opposed to
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and superposed with each other. The method includes joining all the films with
each other at the opposite end portions to make a plastic bag.
The plastic bag may be an internal bag received in a bag in box.
The method may include joining the external and internal films and the
additional body with each other at the other end portion of the composite film
so
that a handle should be formed of the composite film.
Brief Description of the Drawings
Fig. 1 is a side view (A) of a preferred embodiment of the invention and a
plan view (B) of the plastic films of (A).
Fig. 2 is an elevational view (A) of a plastic bag obtained by the
apparatus of Fig. 1, a sectional view (B) of the plastic bag of (A), an
explanatory
view (C) of the plastic bag of (B) and an explanatory view (D) of a plastic
bag of
prior art.
Fig. 3 is a side view (A) of another embodiment and an enlarged view (B)
of the plastic films of (A).
Fig. 4 is a side view (A) of another embodiment and a plan view (B) of the
plastic films of (A).
Fig. 5 is a side view (A) of another embodiment, an enlarged view (B) of
the plastic films of (A) and a plan view (C) of the plastic films of (A).
Fig. 6 is an explanatory view (A) of another embodiment and a sectional
view (B) of another embodiment.
Fig. 7 is a side view (A) of another embodiment, a plan view (B) of the
plastic films of (A), a side view (C) of the step next to (A) and an enlarged
view
(D) of the plastic films of (A).
Fig. 8 is a perspective view (A) of a handle obtained by the apparatus of
Fig. 7, a sectional view (B) of the handle of (A) and an explanatory view (C)
of
the handle of (B).
Fig. 9 is a side view (A) of another embodiment and an enlarged view (B)
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of the plastic films of (A).
Fig. 10 is a side view (A) of another embodiment, a plan view (B) of the
plastic films of (A), a side view (C) of the step next to (A) and an enlarged
view
(D) of the plastic films of (a
Fig. 11 is a side view (A) of another embodiment, an enlarged view (B) of
the plastic films of (A) and a plan view (C) of the plastic films of (A).
Best Mode to Carry Out the Invention
Turning now to the drawings, Fig. 1 illustrates an apparatus for
successively making plastic bags by using a plastic film joining method
according
to the invention. The plastic bag is an internal bag received in a bag in box.
In
the method, a composite film Co is composed of external and internal films 1
and
2 opposed to and superposed with each other, to have opposite end portions 3,
as shown in Fig. 2. The composite film Co is opposed to and superposed with an
additional body Ad. The method includes joining the external and internal
films 1
and 2 and the additional body Ad with each other at one of the opposite end
portions 3 so that a first joining portion 4 should be formed between the
external
and internal films 1 and 2, a second joining portion 5 being formed between
the
internal film 2 and the additional body Ad. The first joining portion 4 has a
first
joining width W1 and includes first outer and inner edges El and El' formed by
the first joining width Wl. The second joining portion 5 has a second joining
width W2 and includes second outer and inner edges E2 and E2' formed by the
second joining width W2.
In the embodiment, the additional body Ad comprises a composite film
composed of external and internal films 6 and 7, to have opposite end portions
3.
It should therefore be understood that the internal bag includes two of the
composite films Co and Ad opposed to and superposed with each other. The
method includes joining all the films 1, 2, 6 and 7 with each other at the
opposite
end portions 3 of the composite films 'Co and Ad so that a first joining
portion 8
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=
should be formed between the external and internal films 6 and 7, the second
joining portion 5 being formed between the internal films 2 and 7. The
external
and internal films 1, 2, 6 and 7 comprise plastic films.
The external and internal films 1, 2, 6 and 7 are rectangular in shape to
have the opposite end portions 3 in directions of length and width of the
plastic
bag. The method includes joining all the films 1, 2, 6 and 7 with each other
at
the opposite end portions 3 in the directions of length and width of the
plastic
bag. The first joining portions 4 is therefore formed between the external and
internal films 1 and 2 at the opposite end portions 3 in the directions of
length
and width of the plastic bag. The first joining portion 8 is also formed
between
the external and internal films 6 and 7 at the opposite end portions in the
directions, the second joining portion 5 being formed between the internal
films 2
and 7 at the opposite end portions 3 in the directions. In addition, for
example,
the external and internal films 1 and 2 are provided with a spout 9, making
the
plastic bag of the plastic films 1, 2, 6 and 7 and the spout 9.
In order to make the plastic bag of Fig. 2, in the apparatus of Fig. 1, the
external and internal films 1, 2, 6 and 7 are opposed to and superposed with
each
other and fed longitudinally thereof. The apparatus includes a feeding device
comprising feeding rollers. The external and internal films 1, 2, 6 and 7 are
directed to and sandwiched between the feeding rollers which are rotated by a
drive motor so that the external and internal films 1, 2, 6 and 7 should be
fed
longitudinally thereof or in a direction X.
In the apparatus, the method is essential to improve the plastic bag, not
resulting in break of the plastic bag. The method comprises making an
adjustment of the first or second joining width W1 or W2, the first joining
width
W1 being less than the second joining width W2 so that the first inner edge
El'
should be formed outwardly of the second inner edges E2' (Fig. 2 a
In the embodiment, making the adjustment comprises preparing first and
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second heaters 10, 11, 12 and 13 for the first and second joining portions 4,
5
and 8. The external and internal films 1, 2, 6 and 7 are fed intermittently
for a
length and temporarily stopped whenever being fed intermittently. The first
heater 10 and 11 is pressed against the external and internal films 1, 2. 6
and 7
while the second heater 12 and 13 is pressed against the internal films 2 and
7
when the external and internal films 1, 2, 6 and 7 are temporarily stopped
whenever being fed intermittently, to heat seal and join all the films 1, 2, 6
and 7
with each other.
In addition, firstly, the internal film 2 is superposed with the additional
body Ad, the second heater 12 and 13 being pressed against the internal film 2
and the additional body Ad to heat seal and join the internal film 2 and the
additional body Ad with each other and make the second joining portion 5
formed.
In the embodiment, the additional body Ad comprises the composite film
composed of the external and internal films 6 and 7. The internal film 2 is
therefore superposed with the internal film 7, the second heater 12 and 13
being
pressed against the internal films 2 and 7 to heat seal and join the internal
films
2 and 7 with each other and make the second joining portion 5 formed. The
second heater 12 and 13 includes an effective width predetermined for
adjustment of the second joining width W2. For example, the internal films 2
and
7 go forward and horizontally to be directed to the second heater 12 and 13.
The second heater 12 and 13 comprises longitudinal and cross heaters. The
longitudinal heater 12 is pressed against the inner films 2 and 7 to heat seal
and
join the internal films 2 and 7 longitudinally thereof so that the second
joining
portion 5 should be formed longitudinally of the inner films 2 and 7. The
cross
heater 13 is pressed against the inner films 2 and 7 to heat seal and join the
internal films 2 and 7 widthwise thereof so that the second joining portion 5
should be formed widthwise of the inner films 2 and 7. The longitudinal and
cross heaters 12 and 13 have the effective width predetermined for adjustment
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of the second joining width W2.
Subsequently, the external film 1 is superposed with the internal film 2,
the first heater 10 and 11 being pressed against the external and internal
films 1
and 2 and the additional body Ad to heat seal and join the external and
internal
films 1 and 2 with each other and make the first joining portion 4 formed. In
the
embodiment, the external film 1 is superposed with the internal film 2 while
the
external film 6 is superposed with the internal film 7, the first heater 10
and 11
being pressed against the external and internal films 1, 2, 6 and 7 to heat
seal
and join the external and internal films 1, 2, 6 and 7 with each other and
make
the first joining portions 4 and 8 formed. The first heater 10 and 11 has an
effective width predetermined for adjustment of the first joining width W1.
For
example, the internal films 2 and 7 are directed to guide rollers 14 after
heat
sealing and joining them. The external films 1 and 6 go forward and upward and
downward to be directed to and guided by the guide rollers 14 so that the
external films 1 and 6 should be superposed with the internal films 2 and 7.
The
external and internal films 1, 2, 6 and 7 are then sandwiched between the
guide
rollers 14- and directed to the first heater 10 and 11. The guide rollers 14
may
be used as the feeding rollers by which the external and internal films 1, 2,
6 and
7 are fed intermittently. In addition, the first heater 10 and 11 comprise
longitudinal and cross heaters. The longitudinal heater 10 is pressed against
the
external and internal films 1, 2, 6 and 7 to heat seal and join the external
and
internal films 1, 2, 6 and 7 longitudinally thereof so that the first joining
portions
4 and 8 should be formed longitudinally of the external and internal films 1,
2., 6
and 7. The cross heater 11 is pressed against the external and internal films
1,
2, 6 and 7 to heat seal and join the external and internal films 1, 2, 6 and 7
widthwise thereof so that the first joining portions 4 and 8 should be formed
widthwise of the external and internal films 1, 2, 6 and 7. The longitudinal
and
cross heaters 10 and 11 have the effective width predetermined for adjustment
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of the first joining width Wl.
The first and second joining portions 4, 5 and 8 are therefore formed
longitudinally and widthwise of the external and internal films 1, 2, 6 and 7.
In
this connection, it should be understood that the first and second joining
portions 4, 5 and 8 are formed along the opposite side edges of the external
and
internal films 1, 2, 6 and 7 when being formed longitudinally of the external
and
internal films 1, 2, 6 and 7. The opposite side edges therefore constitute the
opposite end portions 3 in the direction of length of the plastic bag of Fig.
2.
The external and internal film' s 1, 2, 6 and 7 are then cross cut widthwise
thereof
by a cross cutter when they are temporarily stopped whenever being fed
intermittently, to successively make the plastic bags of the external and
internal
films 1, 2, 6 and 7. In this connection, it should be understood that the
external
and internal films 1, 2, 6 and 7 are cross cut at a position of center of the
first
and second joining portions 4, 5 and 8 formed widthwise of the external and
internal films 1, 2, 6 and 7, to constitute the opposite end portions in the
direction of width of the plastic bag of Fig. 2.
In addition, the external and internal films 1 and 2 are provided with the
spout 9 when making the plastic bag, as in the case of the plastic bag of
Japanese Laid¨Open Patent Publication No. 2007-238129, Japanese Laid¨Open
Patent Publication No. 2011-235933 and Japanese Patent Publication No.
3324953. =
Accordingly, in each of the opposite end portions 3 in the directions of
length and width of the plastic bag of Fig. 2, the first joining width W1 can
be less
than the second joining width W2 by the adjustment of them, so that the first
inner edges El' should be formed outwardly of the second inner edge E2'. For
example, the first inner edges El' are formed outwardly of the second inner
edge
E2' at a distance D more than half of the thickness of internal film 2 or 7.
The
first and second outer edges El and E2 are coincident with each other.
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The plastic bag has therefore no problem when being used as the internal
bag received in the bag in box. The external and internal films 1, 2, 6 and 7
are
subjected to an impact load when dropping the internal bag, as described
previously so that the second joining portion 5 must be subjected to a stress
FO
and a component Fl, between the internal films 2 and 7. However, the first
joining portions 4 and 8 are also subjected to the stress FO and the component
Fl, between the external and internal films 1, 2, 6 and 7 by reason that the
first
inner edges El' are formed outwardly of the second inner edges E2'. The stress
FO and the component Fl are therefore not concentrated on the second joining
portion 5 but divided by the first and second joining portions 4, 5 and 8. As
a
result, the internal films 2 and 7 cannot be peeled and separated off from
each
other at the second joining portion 5, not resulting in break of the internal
bag.
In addition, the plastic bag is filled with and inflated by content so that
the external films 1 and 6 should be bent at the first inner edges El', the
internal
films 2 and 7 being bent at the second inner edge E2'. However, the distance D
is predetermined as more than half of the thickness of internal film 2 or 7,
between the first and second inner edges El' and E2', as described previously.
The stress FO and the component Fl can therefore be divided by the first and
second joining portions 4, 5 and 8 regardless of the internal films 2 and 7
being
bent at the second inner edge E2', involving no problem.
In the interior bag of prior art, the first and second joining widths W1 and
W2 are identical with each other so that not only the first and second outer
edges El and E2 but also the first and second inner edges El' and E2' should
be
coincident with each other (Fig. 2 D). The external and internal films 1, 2, 6
and
7 are therefore subjected to an impact load when dropping the internal bag so
that a stress FO and a component Fl must be concentrated on the second joining
portion 5 formed between the internal films 2 and 7. In comparison with the
case of being divided by the first and second joining portions 4, 5 and 8, the
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stress FO and the component Fl are doubled in strength when being concentrated
on the second joining portion 5. The internal films 2 and 7 may therefore be
peeled and separated off from each other at the second joining portion 5,
resulting in break of the internal bag, as described previously.
In the embodiment, in view of the fact that each of the internal films 2
and 7 often has a thickness of about 0.075 mm, the distance D is predetermined
as more than 0.04 mm. The distance D is therefore more than half of the
thickness of internal film 2 or 7. In addition, when the distance D is more
than
0.04 mm, the internal film 2 or 7 is available if being thicker. The stress FO
and
the component Fl can be divided by the first and second joining portions 4, 5
and
8 regardless of the thickness of internal film 2 or 7. They cannot be
concentrated on the second joining portion 5.
The distance D should be predetermined not to be more than 5 mm. In
the embodiment, the distance D is therefore predetermined to 0.04 - 5 mm.
In another embodiment of Fig. 3, making the adjustment comprises
preparing a heater 15 and 16 for the first and second joining portions 4, 5
and 8.
The heater 15 and 16 is pressed against the external and internal films 1, 2,
6
and 7 when the external and internal films 1, 2, 6 and 7 are stopped
temporarily
whenever being fed, as in the case of the heaters 10, 11, 12 and 13 of Fig. 1.
In addition, a coating of anti-adhesive agent 17 is formed between the
external and internal films 1 and 2 when the external and internal films 1 and
2
and the additional body Ad are superposed with each other. In the embodiment,
the coating of anti-adhesive agent 17 is formed between the external and
internal
films 1 and 2 while the coating of anti-adhesive agent 17 is formed between
the
external and internal films 6 and 7 when the external and internal films 1, 2,
6
and 7 are superposed with each other. The coating of anti-adhesive agent 17
may comprise a coating of heat-resisting ink.
Subsequently, the heater 15 and 16 is pressed against the external and
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internal films 1 and 2 and the additional body Ad to heat seal and join the
external and internal films 1 and 2 and the additional body Ad with each other
and make the first and second joining portions 4 and 5 formed. In the
embodiment, the heater 15 and 16 is pressed against the external and internal
films 1, 2, 6 and 7 to heat seal and join all the films 1, 2, 6 and 7 with
each other
and make the first and second joining portions 4, 5 and 8 formed. The heater
15
and 16 comprises longitudinal and cross heaters. The longitudinal heater 15 is
pressed against the external and internal films 1, 2, 6 and 7 to heat seal and
join
all the films 1, 2, 6 and 7 longitudinally thereof so that the first and
second
joining portions 4, 5 and 8 should be formed longitudinally of the external
and
internal films 1, 2, 6 and 7. The cross heater 16 is pressed against the
external
and internal films 1, 2, 6 and 7 to heat seal and join all the films 1, 2, 6
and 7
widthwise thereof so that the first and second joining portions 4, 5 and 8
should
be formed widthwise of the external and internal films 1, 2, 6 and 7. Each of
the
coatings of anti¨adhesive agent 17 is disposed at a position and in a range
predetermined for adjustment of the first joining width Wl. In this
connection, it
should be understood that the longitudinal and cross heaters 15 and 16 cannot
heat seal and join the external and internal films 1, 2, 6 and 7 with each
other at
the positions and the ranges of coating of anti¨adhesive agent 17, when being
pressed.
The external and internal films 1, 2, 6 and 7 are then cross cut widthwise
thereof by a cross cutter, to successively make the plastic bags, as in the
case
of the embodiment of Fig. 1.
The first joining width W1 can therefore be less than the second joining
width W2 by the adjustment, so that the first inner edge El' should be formed
outwardly of the second inner edge E2'. The stress FO and the component Fl
are not concentrated on the second joining portion 5 but divided by the first
and
second joining portions 4, 5 and 8. As a result-, the internal films 2 and 7
cannot
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be peeled and separated off from each other at the second joining portion 5,
not
resulting in break of the internal bag.
In another embodiment of Fig. 4, making the adjustment comprises
preparing a first irradiator 18 for irradiating laser-beam 19 between and onto
the
external and internal films 1 and 2. For example, pressure rollers 20 are
opposed to each other, the external and internal films 1, 2, 6 and 7 being fed
longitudinally thereof and directed to and curved along the pressure rollers
20 to
have curved portions before being directed to the feeding rollers. Wedged
clearances 21 are therefore formed between the curved portions of external and
internal films 1 and 2, between the curved portions of internal films 2 and 7
and
between the curved portions of external and internal films 6 and 7. The first
irradiator 18 is disposed in the wedged clearance 21 of external and internal
films
1 and 2 to irradiate laser-beam 19 between and onto the external and internal
films 1 and 2.
In addition, a first scanning device 22 is connected to the first irradiator
18 to move the first irradiator 18 in opposite directions Y so that the
external
and internal films 1 and 2 should be scanned with the first irradiator 18,
welding
and joining the external and internal films 1 and 2 with each other. In the
embodiment, the external and internal films 1 and 2 are scanned with the first
irradiator 18, heating and melting the external and internal films 1 and 2
with the
laser-beam. The external and internal films 1 and 2 are then superposed with
each other and sandwiched between and pressurized by the pressure rollers 20,
welding and joining the external and internal films 1 and 2 with each other.
Making the adjustment further comprises preparing a second irradiator 23
for irradiating laser-beam 19 between and onto the internal film 2 and the
additional body Ad. In the embodiment, the second irradiator 23 is disposed in
the wedged clearance 21 of internal films 2 and; 7 to irradiate laser-beam 19
between and onto the internal films 2 and 7. Furthermore, an additional
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irradiator 24 is disposed in the wedged clearance 21 of external and internal
films
6 and 7 to irradiate laser¨beam 19 between and onto the external and internal
films 6 and 7.
In addition, a second scanning device is connected to the second
irradiator 23 to move the second irradiator 23 in the opposite directions Y so
that the internal film 2 and the additional body Ad should be scanned with the
second irradiator 23, welding and joining the internal film 2 and the
additional
body Ad with each other. In the- embodiment, the internal films 2 and 7 are
scanned with the second irradiator 23, heating and melting the internal films
2
and 7 with the laser¨beam. An additional scanning device is connected to the
additional irradiator 24 to move the additional irradiator 24 in the opposite
directions Y so that the external and internal films 6 and 7 should be scanned
with the additional irradiator 24, heating and melting the external and
internal
films 6 and 7 with the laser¨beam 19. The internal films 2 and 7 and the
external film 7 are then superposed with each other and sandwiched between and
pressurized by the pressure rollers 20, welding and joining the internal film
2 and
the external and internal films 6 and 7 with each other.
In the embodiment, the external and internal films 1, 2, 6 and 7 are fed
longitudinally thereof, when irradiating the laser beam 19. In addition, it
is
intended to move the first, second and additional irradiators 18, 23 and 24
widthwise of the external and internal films 1, 2, 6 and 7 or in the opposite
directions Y. The first and second joining portions 4, 5 and 8 can therefore
be
formed longitudinally and widthwise of the external and internal films 1, 2, 6
and 7.
Each of the first, second and additional irradiators 18, 23 and 24 may
comprise
two irradiators spaced from each other widthwise of the external and internal
films 1, 2, 6 and 7. In this case, the first and second joining portions 4, 5
and 8
can be formed longitudinally and along the opposite side edges of the external
and internal films 1, 2, 6 and 7 without difficulty. Each of the first, second
and
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additional scanning devices 22 may comprise a galvanometer mirror to make the
external and internal films 1, 2, 6 and 7 scanned exactly.
In addition, in the embodiment, a control device 25 is connected to the
first, second and additional irradiators 18, 23 and 24 and the first, second
and
additional scanning devices 22 to control the first, second and additional
irradiators 18, 23 and 24 and the first, second and additional scanning
devices 22
individually for adjustment of the first and second joining widths W1 and W2.
The control device 25 may be connected to the drive motor by which the
feeding rollers are rotated and the external and internal films 1, 2, 6 and 7
are
fed, controlling the drive motor to change the feeding speed. The control
device
25 may be arranged to control all the scanning devices 22 to change the
scanning
speed. The control device 25 may be arranged to control the drive motor and
all
the scanning devices 22 to move all the irradiators 18, 23 and 24 in the
opposite
directions reciprocatingly at a pitch of 0.05 - lmm predetermined in the
feeding
direction X. The control device 25 may be arranged to change the stroke and
position of the irradiators 18, 23 and 24 when moving them reciprocatingly.
The
first and second joining portions 4, 5 and 8 can therefore be formed to have
any
direction, width and shape predetermined. The control device 25 may be
arranged to control all the irradiators 18, 23 and 24 to change the amount of
light
for adjustment of the joining strength.
The external and internal films 1, 2, 6 and 7 are then cross cut widthwise
thereof, to successively make the plastic bags.
The first joining width W1 can therefore be less than the second joining
width W2 by the adjustment, so that the first inner edge El' should be formed
outwardly of the second inner edge E2'.
In another embodiment of Fig. 5, an irradiator 26 is opposed to the
external and internal films 1 and 2 and the additional body Ad superposed with
each other to irradiate laser¨beam 19 onto the external and internal films 1
and 2
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CA 02832856 2013-11-08
and the additional body Ad. In the embodiment, the irradiator 26 is disposed
on
the upper side of the external and internal films 1, 2, 6 and 7 superposed
with
each other to be opposed to the external and internal films 1, 2, 6 and 7,
irradiating the laser¨ beam 19 onto them. The irradiator 26 may be disposed on
the lower side of the external and internal films 1, 2, 6 and 7. The external
and
internal films 1, 2, 6 and 7 are then directed to, sandwiched between and
pressurized by the pressure rollers 20.
In addition, treatments of laser absorption are applied between the
external and internal films 1 and 2 and the additional body Ad to weld and
join
the external and internal films 1 and 2 and the additional body Ad with each
other
by irradiating the laser¨beam, as in the case of those of Japanese Patent
Publication No. 4104073. In the embodiment, the treatments of laser absorption
are applied between all the films 1, 2, 6 and 7 and in the joining portions 4,
5 and
8, to weld and join all the films 1, 2, 6 and 7 with each other. For example,
the
treatments of laser absorption may comprise treatments of surface asperity. It
may comprise coatings of laser absorption agent or coatings of ink formed
between all the films 1, 2, 6 and 7.
In addition, the external and internal films 1, 2, 6 and 7 are fed
longitudinally thereof. A scanning device 22 is connected to the irradiator 26
to
move the irradiator 26 widthwise of the external and internal films 1, 2, 6
and 7
or in the opposite directions Y so that the external and internal films 1, 2,
6 and
7 should be scanned with the irradiator 26, heating and melting the external
and
internal films 1, 2, 6 and 7 with the laser¨beam 19. A control device 25 is
connected to the irradiator 26 and the scanning device 22 to control the
irradiator 26 and the scanning device 22.
The joining portions 4, 5 and 8 can therefore be formed longitudinally and
widthwise of the external and internal films 1, 2, 6 and 7 by the treatments
of
laser absorption applied longitudinally and widthwise of the external and
internal
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CA 02832856 2013-11-08
films 1, 2, 6 and 7. In addition, the treatments of laser absorption are
disposed
at positions and in ranges predetermined for adjustment of the first and
second
widths W1 and W2.
The external and internal films 1, 2, 6 and 7 are then cross cut widthwise
thereof, to successively make the plastic bags.
The first joining width W1 can therefore be less than the second joining
width W2 by the adjustment, so that the first inner edge El' should be formed
outwardly of the second inner edge E2'.
In the embodiments of Figs. 1 to 5, an intermediate film 27 may be
interposed between the external and internal films 1 and 2, an intermediate
film
28 being interposed between the external an.d internal films 6 and 7, as shown
in
Fig. 6 (Fig. 6 A). The method includes joining the external, intermediate and
internal films 1, 2, 6, 7, 27 and 28 with each other. Accordingly, the first
joining
portion 4 comprises a plurality of joining portions. The first joining portion
8
comprises a plurality of joining portions. The first joining width W1
comprises a
plurality of joining widths. The first inner edge El' comprises a plurality of
inner
edges. The plurality of joining widths W1 are predetermined to be less in
stages.
The plurality of inner edges El' are formed outwardly in stages. The plurality
of
inner edges El' may be formed outwardly in stages at a distance more than half
of the thickness of internal film 2 or 7 or the intermediate film 27 or 28.
The
distance may be predetermined more than 0.04 mm.
In this case, all the joining portions 4, 5 and 8 are subjected to the
stress FO and the component Fl. The stress FO and the component Fl are
therefore not concentrated on the second joining portion 5 but divided by all
the
joining portions 4, 5 and 8. As a result, the internal films 2 and 7 cannot be
peeled off from each other at the second joining portion 5, not resulting in
break
of the internal bag.
The intermediate film 27 may comprise a plurality of films, the
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CA 02832856 2013-11-08
intermediate film 28 comprising a plurality of films. The method includes
joining
all the films with each other, all the joining widths being predetermined to
be less
in stages, all the inner edges being formed outwardly in stages.
The additional body may comprise the other end portion 3 of the
composite film Co (Fig. 6 B). The composite film Co is bent to have the
opposite end portions 3 opposed to and superposed with each other. The
method includes joining all the films 1 and 2 with each other at the opposite
end
portions 3 to make a plastic bag of the external and internal films 1 and 2.
The method may include adhering and joining all the films with each other
with adhesive agent applied onto the external and internal films.
Fig. 7 illustrates an apparatus for successively making plastic bags and
handles by using the plastic film joining method according to the invention.
In
the embodiment, a composed film Co is composed of external and internal films
29 and 30 opposed to and superposed with each other, to have opposite end
portions 31, as shown in Fig. 8. The composite film Co is opposed to and
superposed with an additional body Ad. The method includes joining the
external
and internal films 29 and 30 and the additional body Ad with each other at the
opposite end portions 31 so that a first joining portion 32 should be formed
between the external and internal films 29 and 30, a second joining portion 33
being formed between the internal film 30 and the additional body Ad. The
first
joining portion 32 has a first joining width W1 and includes first outer and
inner
edges El and El' formed by the first joining width Wl. The second joining
portion 33 has a second width W2 and includes second outer and inner edges E2
and E2' formed by the second joining width W2.
In the embodiment, the composite film Co is elongated to have a length
so that the handle should be formed of the composite film Co. The external and
internal films 29 and 30 comprise plastic films. On the other hand, the
additional
body Ad comprises a base film 34. The base film 34 also comprises a plastic
19
CA 02832856 2013-11-08
film. The apparatus is arranged to successively make plastic bags of the base
film 34.
In order to make the plastic bag and the handle of Fig. 8, in the
apparatus of Fig. 7, the external and internal films 29 and 30 and the base
film 34
are superposed with each other and fed longitudinally thereof or in a
direction X,
as in the case of the embodiment of Fig. 1. The method comprises making an
adjustment of the first or second joining widths WI or W2, the first joining
width
WI being less than the second joining width W2 so that the inner edge El'
should
be formed outwardly of the second inner edge E2' (Fig. 8 C).
In the embodiment, making the adjustment comprises preparing first and
second heaters 35 and 36 for the first and second joining portions 32 and 33.
The external and internal films 29 and 30 and the base film 34 are fed
intermittently for lengths and stopped temporarily whenever being fed
intermittently. The first heater 35 is pressed against the external and
internal
films 29 and 30 and the base film 34 while the second heater 36 is pressed
against the internal film 30 and the base film 34 when the base film 34 is
stopped
temporarily whenever being fed intermittently, to heat seal and join the
external
and internal films 29 and 30 and the base film 34 with each other.
In addition, firstly, the internal film 30 is superposed with the base film
34 and directed to the second heater 36. The second heater 36 is pressed
against the internal film 30 and the base film 34 to heat seal and join the
internal
film 30 and the base film 34 with each other and make the second joining
portion
33 at one of the end portions of the internal film 30 when the base film 34 is
stopped temporarily (Fig. 7 A). The second heater 36 includes an effective
width
predetermined for adjustment of the second joining width W2. The external film
29 is directed to the first heater 37 for waiting.
Subsequently, the base film 34 is fed again. The internal film 30 is
therefore pulled and fed by the base film 34 so that the external film 29
should
CA 02832856 2013-11-08
be superposed with the internal film 30 (Fig. 7 C). The base film 34 is then
stopped temporarily. The first heater 35 is pressed against the external and
internal films 29 and 30 and the base film 34 to heat seal and join the
external
and internal films 29 and 30 with each other and make the first joining
portion 32
at one of the end portions of the external and internal films 29 and 30. The
first
heater 35 includes an effective width predetermined for adjustment of the
first
joining width W1. The base film 34 is then fed again so that the external film
29
should be pulled and fed by internal film 30 and the base film 34.
The internal film 30 includes perforations formed therein to extend
widthwise of the internal film 30. The perforations are spaced from each other
at a distance, longitudinally of the internal film 30. In
addition, the internal film
30 is pulled and fed by the base film 34 after heat sealing and joining the
internal
film 30 and the base film 34 at one of the end portions of the internal film
30, as
described previously. The internal film 30 is then stopped by a brake force
when
the perforation reaches the second heater 36. The brake force is applied on
the
internal film 30 at a position upstream of the perforation. The internal film
30 is
therefore pulled by the base film 34 to be torn at the perforation.
Furthermore,
the base film 34 is stopped temporarily immediately before the perforation
reaches the second heater 36. The second heater 36 is pressed against the
internal film 30 and the base film 34 to heat seal and join the internal film
30 and
the base film 34 with each other and make the second joining portion 33
formed.
The base film 34 is then fed again so that the internal film 30 is pulled and
fed by
the base film 34 to be torn at the perforation when the perforation reaches
the
second heater 36. The internal film 30 is torn into a length. It should
therefore
be understood that the second heater 36 can heat seal and join the internal
film
30 and the base film 34 with each other and make the second joining portion 33
formed at the other end portion of the internal film 30.
The external film 29 also includes perforations formed therein to extend
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CA 02832856 2013-11-08
widthwise of the external film 29. The perforations are spaced from each other
at the same distance as the internal film 30, longitudinally of the external
film 29.
In addition, the external film 29 is pulled and fed by internal film 30 and
the base
film 34 after heat sealing and joining the external and internal films 29 and
30 at
one of the end portions thereof. The external film 29 is then stopped by a
brake
force when the perforation reaches the first heater 35. The brake force is
applied on the external film 29 at a position upstream of the perforation. The
external film 29 is therefore pulled by the base film 34 to be torn at the
perforation. Furthermore, the base film 34 is stopped temporarily immediately
before the perforation reaches the first heater 35. The first heater 35 is
pressed against the external and internal films 29 and 30 and the base film 34
to
heat seal and join the external and internal films 29 and 30 with each other
and
make the first joining portion 32 formed. The base film 34 is then fed again
so
that the external film 29 is pulled and fed by the base film 34 to be torn at
the
perforation when the perforation reaches the first heater 35. The external
film
29 is torn into the same length as the internal film 30. It should therefore
be
understood that the first heater 35 can heat seal and join the external and
internal films 29 and 30 with each other and make the first joining portion 32
formed at the other end portions of the external and internal films 29 and 30.
The base film 34 is fed again so that the external and internal films 29
and 30 should be fed by the base film 34 after being torn. The base film 34 is
then stopped temporarily. The second heater 36 is pressed against the internal
film 30 and the base film 34 to heat seal and join them again at one of the
end
portions of the internal film 30. The steps are then performed repeatedly, as
described previously.
The method can therefore heat seal and join the external and internal
films 29 and 30 and the base film 34 with each other and make the first and
second joining portions 32 and 33 formed at the opposite end portions of the
22
CA 02832856 2013-11-08
external and internal films 29 and 30. Accordingly, the handle can be formed
of
the composite film Co composed of the external and internal films 29 and 30
after making the plastic bag of the base film 34.
In addition, the first joining width W1 can be less than the second joining
width W2 by the adjustment, so that the first inner edge El' should be formed
outwardly of the second inner edge E2'. For example, the first inner edge El'
is
formed outwardly of the second inner edge E2' at a distance D more than half
of
the thickness of internal film 30. The distance D may be predetermined as more
than 0.04 mm. As a result, the internal film 30 and the base film 34 cannot be
peeled and separated off from each other at the second joining portion 33,
keeping the handle from being disconnected from the plastic bag.
In another embodiment of Fig. 9, making the adjustment comprises
preparing a heater 37 for the first and second joining portions 32 and 33. In
addition, a coating of anti¨adhesive.agent 38 is formed between the external
and
internal films 29 and 30 when the external and internal films 29 and 30 and
the
base film 34 are superposed with each other. The coating of anti¨adhesive
agent may comprise a coating of heat¨resisting ink.
Subsequently, the heater 37 is pressed against the external and internal
films 29 and 30 and the base film 34 to heat seal and join the external and
- internal films 29 and 30 and the base film 34. The first joining portion 32
is
therefore formed between the external and internal films 29 and 30, the second
joining portion 33 being formed between the internal film 30 and the base film
34.
The heater 37 may comprise two heaters to heat seal and join the external and
internal films 29 and 30 and the base film 34 and make the first and second
joining portions 32 and 33 formed at the opposite end portions of the external
and internal films 29 and 30. The coating of anti¨adhesive agent 38 is formed
between the external and internal films 29 and 30 at each of the end portions
thereof. In addition, the coating of anti¨adhesive agent 38 is disposed at a
23
CA 02832856 2013-11-08
=
position and in a range predetermined for adjustment of the first joining
width Wl.
In this connection, it should be understood that the heater 37 cannot heat and
join the external and internal films 29 and 30 at the position and in the
range of
coating of anti¨adhesive agent 38, when being pressed.
The handle can therefore be formed of the composite film Co composed
of the external and internal films 29 and 30 after making the plastic bag of
the
base film 34.
In addition, the first joining width W1 can be less than the second joining
width W2 by the adjustment, so that the first inner edge El' should be formed
outwardly of the second inner edge E2'.
In another embodiment of Fig. 10, making the adjustment comprises
preparing first and second irradiators 18 and 23 for irradiating laser¨beam
between and onto the external and internal films 29 and 30 and the base film
34,
as in the case of the embodiment of Fig. 4. The pressure rollers 20 are
opposed
to each other, the external and internal films 29 and 30 and the base film 34
being directed to and curved along the pressure rollers 20 to have curved
portions before being directed to the feeding rollers. A wedged clearance 39
is
therefore formed between the curved portions of external and internal films 29
and 30, a wedged clearance 39 being formed between the curved portions of
internal film 30 and the base film 34. The first and second irradiators 18 and
23
are disposed in the wedged clearances 39 of external and internal films 29 and
30
and base film 34 to irradiate laser¨beam 19 between and onto the external and
internal films 29 and 30 and the base film 34.
In addition, first and second scanning devices 22 are connected to the
first and second irradiators 18 and 23 to move the first and second
irradiators 18
and 23 in opposite directions Y so that the external and internal films 29 and
30
and the base film 34 should be scanned with the first and second irradiators
18
and 23, to heat and melt the external and internal films 29 and 30 and the
base
24
CA 02832856 2013-11-08
film 34 with the laser¨beam. The external and internal films 29 and 30 and the
base film 34 are then superposed with each other and sandwiched between and
pressurized by the pressure rollers 20, to weld and join the external and
internal
films 29 and 30 and the base film 34 with each other.
The external and internal films 29 and 30 and the base film 34 are fed
longitudinally thereof, when irradiating the laser¨beam 19. In addition, it
is
intended to move the first and second irradiators 18 and 23 widthwise of the
external and internal films 29 and 30 and the base film 34 or in the opposite
directions Y. The first and second joining portions 32 and 33 can therefore be
formed longitudinally and widthwise of the external and internal films 29 and
30
and the base film 34. Each of the first and second scanning devices 22 may
comprise a galvanometer mirror to make the external and internal films 29 and
30
and the base film 34 scanned exactly.
In addition, a control device 25 is connected to the first and second
irradiators 18 and 23 and the first and second scanning devices 22 to control
the
first and second irradiators 18 and 23 and the first and second scanning
devices
22 individually for adjustment of the first and second widths W1 and W2.
The external and internal films 29 and 30 includes perforations formed
therein to extend widthwise of the external and internal films 29 and 30. The
perforations are spaced from each other at a length longitudinally of the
external
and internal films 29 and 30. In addition, the external and internal films 29
and
30 are stopped by brake forces when the perforations reach the rollers 20. The
brake forces are applied on the external and internal films 29 and 30 at
positions
upstream of the perforations. The external and internal films 29 and 30 are
therefore pulled by the base film 34 at positions downstream of the
perforations,
to be torn at the perforations (Fig. 10 a In this connection, it is preferable
that one of the rollers 20 is engaged with the base film 34 and rotated by
friction
while the other roller 20 is engaged with the external and internal films 29
and 30
CA 02832856 2013-11-08
and stopped not to be rotated, so that the external and internal films 29 and
30
can be torn without difficulty. One of the rollers 20 may be rotated by the
drive
motor.
Furthermore, the first and second irradiators 18 and 23 irradiate laser¨
beams between and onto the external and internal films 29 and 30 and the base
film 34, the external and internal films 29 and 30 and the base film 34 being
pressurized by the rollers 20, immediately before the perforations reach the
rollers 20. The external and internal films 29 and 30 are then torn at the
perforations when the perforations reach the rollers 20. It should therefore
be
understood that the first and second irradiators 18 and 23 cooperate with the
rollers 20 to weld and join the external and internal films 29 and 30 and the
base
film 34 with each other and make the first and second joining portions 32 and
33
formed at the trailing end portions of the external and internal films 29 and
30.
The base film 34 is then fed again so that the external and internal films 29
and
30 should be pulled and fed by the base film 34 after being torn.
Subsequently, the first and second irradiators 18 and 23 irradiate laser¨
beams again, the external and internal films 29 and 30 being pressurized by
the
rollers 20, after the base film 34 is fed for a length. It should therefore be
understood that the first and second irradiators 18 and 23 cooperate with the
rollers 20 to weld and join the external and internal films 29 and 30 and the
base
films 34 again at the leading end portions of the external and internal films
29
and 30. The brake force is then released so that the external and internal
films
29 and 30 should be pulled and fed by the base film 34.
The first and second irradiators 18 and 20 irradiate laser¨beams again
immediately before the perforations reach the rollers 20, the steps being then
performed repeatedly, as described previously.
The method can therefore weld and join the external and internal films 29
and 30 and the base film 34 with each other and make the first and second
26
CA 02832856 2013-11-08
joining portions 32 and 34 formed at the opposite end portions of the external
and internal films 29 and 30. Accordingly, the handle can be formed of the
composite film Co composed of the external and internal films 29 and 30 after
making the plastic bag of the base film 34.
In addition, the first joining width W1 can be less than the second joining
width W2 by the adjustment, so that the first inner edge El' should be formed
outwardly of the second inner edge E2'.
In another embodiment of Fig. 11, an irradiator 26 is opposed to the
external and internal films 29 and 30 and the base film 34 superposed with
each
other to irradiate laser¨beam onto the external and internal films 29 and 30
and
the base film 34. The external and internal films 29 and 30 and the base film
34
are then directed to and sandwiched between and pressurized by the pressure
rollers 20, as in the case of the external and internal films 1, 2, 6 and 7 of
Fig. 5.
In addition, treatments of laser absorption are applied between the
external and internal films 29 and 30 and the base film 34 to weld and join
the
external and internal films 29 and 30 and the base film 34 with each other by
irradiating the laser¨beam, as also in the case of the embodiment of Fig. 5.
The external and internal films 29 and 30 and the base film 34 are fed
longitudinally thereof. A scanning device 22 is connected to the irradiator 26
while a control device 25 is connected to the irradiator 26 and the scanning
device 22, as also in the case of the embodiment of Fig. 5.
The joining portions 32 and 33 can therefore be formed longitudinally and
widthwise of the external and internal films 29 and 30 and the base film 34 by
the
treatments of laser absorption applied longitudinally and widthwise of the
external and widthwise of the external and internal films 29 and 30 and the
base
film 34. In addition, the treatments of laser absorption are disposed at
positions
and in ranges predetermined for adjustment of the first and second widths W1
and W2
27
CA 02832856 2013-11-08
The handle can therefore be formed by the composite film Co composed
of the external and internal films 29 and 30 after making the plastic bag of
the
base film 34.
In addition, the first joining width W1 can be less than the second joining
width W2 by the adjustment, so that the first inner edge El' should be formed
outwardly of the second inner edge E2'.
In the embodiments of Figs. 7 to 11, an intermediate film may be
interposed between the external and internal films 29 and 30, an intermediate
film
being interposed between the internal film 30 and the base film 34. The method
includes joining the external, intermediate and internal films. The plurality
of
joining widths W1 are predetermined to be less in stages. The plurality of
inner
edges El' are formed outwardly in stages.
The intermediate film may comprise a plurality of films.
Adhesive agent may be applied onto the external and internal films 29
and 30 and the base film 34 to adhere and join the external and internal films
29
and 30 and the base film 34 when making the plastic bag and the handle of Fig.
8.
28
