JPH08216258A - Back sealing method for manufacturing air valve for packaging cushioning material - Google Patents

Abstract

PURPOSE: To effectively back seal to manufacture air valve by a plural-layer film of polyethylene in which the difference of melting points is not increased by rotating heat steel belts at the same speed while bringing a film to be back sealed into pressure contact with the belts. CONSTITUTION: A film (i) mounted at a film holder (s) having a film retainer (t) is introduced to a film former guide (h) via a film tensile roller (j), a film guide roll (k) and a triangular film former (g). The film (i) fed out of the guide (h) becomes the state of two molds opened downward. Both the sides of the opened lower end of the film of the two folds are sandwiched between steel belts (d), and back sealed. A heater (e) made of ceramics supplies heat to back seal via the belts (d) to the film back sealing part. In this case, the belts (d) and the film are rotated at the same speed while bringing the belts (d) into pressure contact with the film.

Description

Detailed Description of the Invention

[0001]

[Industrial field of application] A back seal method in the production of air bubbles used as a cushioning material for packaging.

[0002]

2. Description of the Related Art Conventionally, when manufacturing a back seal for producing an air bubble, as shown in FIGS. 13 and 14, a back seal of a film whose lower end is opened by tension by a film pulling roller a. Back sealer 101b,
101b was closed, and the back was sealed by radiant heat to the gap between the tips. In FIG. 14, 101c is a back sealer 101.
b, 101b is a solenoid for opening and closing.

In such a back-sealing method, since the radiant heat is used for sealing without pressure contact, the temperature of the heater must be raised considerably so that the surface layer does not melt even if the film directly touches the heater. In other words, the difference in melting point between the surface layer of the film and the sealing layer is large, and stable back sealing is difficult unless a different film such as a polyester layer and a polyethylene layer is used. It was difficult to use a multi-layer film made of polyethylene, which does not have a large difference in melting point.

[0004]

The melting point difference is not large. Specifically, a back seal for producing air bubbles made of a polyethylene multi-layer film having a melting point difference of 50 ° C. or less is used.
Be sure to do it at a speed of 30 m or more per minute. Therefore, at the time of back sealing, a constant pressure contact force to the film, a manufacturing process that maintains a constant heating time at a constant temperature lower than the seal by radiant heat, and a combination of a ceramic heater and a steel belt with less wear To be possible.

[0005]

[Technical Means] A polyethylene multilayer film having a melting point higher than that of a sealing layer ic for a surface layer ia, or a method for producing an air bubble for a packing cushioning material using a polyethylene multilayer film having a melting point difference of 50 ° C. or less,

As a back seal unit, a ceramic heater e is fixed to a back seal unit mounting plate w, slides on the ceramic heater e to rotate the heat steel belt d, and is advanced with respect to the lower end open film to be back sealed. , The one that is arranged so that it can move backward, the first
Then, tension is applied to the film by the film pulling roller a, and the back seal unit is retracted from the film,

Secondly, the film pulling roller a is rotated to advance the film, and the heat steel belt d is slid and rotated on the ceramic heater e at the same speed as the film, while the spine seal unit is advanced and pressed. Shishi seal is performed continuously,

Thirdly, when the bubble production is stopped, the back seal unit is retracted while the steel belt d is rotated, the rotation of the film pulling roller and the steel belt is stopped during or after the retreat, and fourthly, when the film is removed. , The film pulling roller a is released from the film.
An air bubble manufacturing method characterized by these steps.

The hardness of the ceramic heater e is set higher than that of the heat steel belt d, and the upper end of the heat steel belt d is positioned higher than the upper end of the ceramic heater e.

[0010]

[Action]

(A) Since the heat steel belt d is rotated at the same speed while being pressed against the film to be back-sealed, stable back-sealing can be performed while advancing the film.

(B) Since the hardness of the ceramic heater e is selected to be higher than that of the heat steel belt d, the ceramic heater e does not wear for a long period of time.

(C) The temperature of the upper edge portion of the heat steel belt d, which is likely to be stressed to the film, can be set to the melting point of the seal layer or less, and the film strength can be maintained. Further, by installing the ceramic heater e in a position where stress is not applied to the film, stable back sealing can be performed.

[0013]

【effect】

(A) Since the heat steel belt d and the film are rotated at the same speed while being in pressure contact with each other, it is possible to mass-produce the polyethylene film at a speed of 30 m or more for 1 minute without applying an abnormal stress. (B) The ceramic heater e has a long life. (C) Since the upper end of the heat steel belt d is set higher than the upper end of the ceramic heater e, the back seal can be surely made and the peeling does not occur during use.

[0014]

FIG. 1 is a perspective view of an apparatus used in the method of the present invention,
FIG. 2 is a view taken along arrow f2-f2 of FIG. 1, except for the film i wound up. 3 is a front view and FIG. 4 is a plan view.

The film i wound in FIG. 1 is rewound by the rotation of the tension roller a. Film presser t
Film i attached to a film holder s having
Is a film pulling roller j, a film guide roll k
Through the film former g of the triangular plate and enter the film former guide h. The film i exiting the film former guide h is folded in two with the lower part opened.

Both sides of the open lower end of the double-folded film are sandwiched by steel belts d and sealed at the back. In FIG. 3, q is air, and v is an air pipe for blowing air q into a vertically long film.

The ceramic heater e supplies heat for back sealing to the film back sealing portion via the steel belt d. Thus, the film pipe having the sectional shape shown in FIG. 5A is formed.

The film having the cross-sectional shape shown in FIG. 5 (a) has a perfect circular cross-section as shown in FIG. 5 (b) as a result of blowing air q, and the lateral sealer u has the laterally flat cross-sectional shape shown in FIG. 5 (c). , You can make a bubble. 6 (a) is a perspective view of FIG. 5 (b), FIG. 6 (b) is a perspective view of an air bubble, and FIG. 6 (c).
Is a plan view of FIG.

P is a display panel, r is a bubble, t is a film holder, s is a film holder, h is a film guide,
n is a bubble outlet cover, c is an operation panel, o is a lower cover, and m is an upper cover. Next, regarding FIGS. 7 to 11,
The details of the processing order of the Cecile will be described.

The film i has a surface layer i as shown in FIG.
It is a multi-layer polyethylene film having different melting points of the layers a, the intermediate layer ib, and the seal layer ic. The melting point of the seal layer ic is lower than that of the surface layer ia within the range of 50 ° C.

The operation of the back seal unit will be described below. FIG. 7: FIG. 7 shows the starting point of the film when the tension roller a grips the folded film. The back seal unit mounting plate w indicates a position retracted from the film i.

FIG. 8: FIG. 8 shows the time when the back seal unit w advances and grips the vertically elongated open lower end from both sides and press-contacts it to continuously perform the back seal. At this time, the traveling speeds of the steel belt d and the film i are the same.

The ceramic heater e is fixed to the back seal unit mounting plate w and moves forward and backward together with the back seal unit w. On the other hand, since the steel belt d slides on the heater e, the hardness of the ceramics heater e is set higher than that of the steel belt d, and the heater e
Prevent wear. Instead of the ceramic heater, a material such as glass having high hardness may be used.

FIG. 9: In FIG. 9, the back seal unit w is retracted when the bubble production is stopped. FIG. 10: When removing the film, the film pulling roller a is opened from the film.

Next, the setting positions of the ceramic heater e and the steel belt d will be described. In FIG. 12, e1 is a heater holder, e2 is a ceramic heater holder, e3 is a rod-shaped heater, and FIG. 12a shows a case where the upper end of the steel belt d coincides with the upper end of the ceramic heater e.

FIG. 12b shows a case where the upper end of the steel belt d is projected from the upper end of the ceramic heater e by a distance α. In FIG. 11a, the heat is applied directly to the upper edge of the heat-steel belt, which stresses the film. In other words, it is easy to make holes, and air leaks easily occur.

On the other hand, in the case of FIG. 12b, the temperature of the upper edge portion of the heat steel belt where the film is likely to be stressed can be set to the melting point of the sealing layer or lower, and the film strength can be maintained. Also, by installing a ceramics heater in a position where stress is not applied to the film, a stable back seal can be achieved.

[Brief description of drawings]

FIG. 1 is a perspective view of the device of the present invention,

FIG. 2 is a view as seen from an arrow f2-f2 in FIG. 1, except that a film i wound up is excluded.

FIG. 3 is a front view of FIG.

FIG. 4 is a plan view of FIG.

FIG. 5 shows changes in the shapes of a, b, c and d films.

6A is a perspective view of a perfect circular film, and FIG. 6B is a perspective view.
Air bubble perspective view, ▲ c ▼ Air bubble plan view,

FIG. 7 is a plan view of a first step of the back seal unit,

FIG. 8 is a plan view of the second step,

FIG. 9 is a plan view of a third step,

FIG. 10 is a plan view of the fourth step,

FIG. 11 is a cross-sectional view of film i,

12A to 12C are explanatory views of setting positions of the back seal unit w.

FIG. 13 is a side view of a conventional back sealing process,

FIG. 14 is a front view of the back seal heater when opened,

FIG. 15 is a front view of the same when sealing,

[Explanation of symbols]

a: film pulling roller, b: heat steel belt driving roller, c: operation panel, d: heat steel belt, e: ceramic heater, f: film guide, g: triangle film former, h:
Film former guide, i: film, ia: surface layer, ib: intermediate layer, ic: seal layer, j: film pulling roller, k: film guide roll, l: film pulling roller opening / closing lever, m: upper cover, n : Bubble outlet cover, o: lower cover, p: display panel, q: air, r: bubble, s: film holder, t: film holder, v: air pipe, w: back seal unit mounting plate, FIG. 13, FIG. 14 101: Back seal unit, 101a: Mounting base, 1
01b: back sealer, 101c: solenoid.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area // B29L 9:00 22:00

Claims (4)

[Claims] 1. A method for producing an air bubble for a packing cushioning material by using a polyethylene multilayer film having a surface layer ia having a melting point higher than that of a seal layer ic, or a polyethylene multilayer film having a melting point difference of 50 ° C. or less, wherein a back seal is used. As a unit, a ceramic heater e is fixed to a back seal unit mounting plate w, and the heat steel belt d is rotated by sliding on the ceramic heater e, and is arranged so that it can be moved forward and backward with respect to the lower end opening film to be back-sealed. First, tension is applied to the film by the film pulling roller a, the back sealing unit is retracted from the film, and secondly, the film pulling roller a is rotated to advance the film and heat the film. The steel belt d slides on the ceramic heater e at the same speed as the film and rotates. While rotating, the spine seal unit is advanced and pressed to continuously perform spine seal. Thirdly, when the bubble production is stopped, the spine seal unit is retracted while the steel belt d is being rotated, and the film is pulled during or after the retraction. Stop the roller and steel belt rotation. Fourthly, when removing the film, the film pulling roller a is opened from the film. A spine sealing method characterized by repeating these steps. 2. The back sealing method according to claim 1, wherein the hardness of the ceramic heater e is higher than the hardness of the heat steel belt d. 3. The back sealing method according to claim 1, wherein the upper end of the heat steel belt d is located higher than the upper end of the ceramic heater e. 4. The back sealing method according to claim 1, wherein a material such as glass having a hardness higher than that of the heat steel belt d is used instead of the ceramics heater e.