JPS6337693B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a method for welding synthetic resin films.

(b) Prior Art Conventionally, when synthetic resin films are to be welded together, a method has been used in which the adhered films are layered and the overlapping portions are heated and pressurized to weld the same films to each other.

(C) Problems to be Solved by the Invention However, when a synthetic resin film that has been subjected to a surface treatment such as antifogging treatment is processed into a bag with the same treated surface as the inner surface, antifogging is applied to the opposing surfaces of the adhered films. The problem is that complete welding cannot be achieved because treatment substances such as chemicals are present and inhibit the welding, and the welded parts are likely to peel off.

(d) Means for Solving the Problems In this invention, upper and lower synthetic resin films, which are double layered by folding the creases in the conveying direction, are heated under pressure with a hot knife, and the same upper and lower films are heated using a hot knife. A method for welding synthetic resin films, which is characterized by applying vibration in a direction perpendicular to the pressure direction to fuse the film at predetermined intervals, and at the same time welding the side edges of the upper and lower films formed by the same melt-cutting. We aim to provide the following.

(e) Functions/Effects In the present invention, when welding the upper and lower films, the vibration of the knife is used in combination with the pressure heating of the hot knife, and the vibration is used to weld the upper and lower films stacked with the anti-fog treated surfaces inside. The antifogging agent present on the welding surfaces is removed by fine lateral sliding between the welding surfaces of the film, thereby welding the synthetic resin layer that is the base material of the film.

In addition, the thickness of the synthetic resin film is at least
In contrast, the thickness of the antifogging agent film is several nanometers, so the antifogging film is applied by applying pressure and heating with a roughly linear hot knife from the welded part of the synthetic resin base of the melted upper and lower films. By extruding the agent to the outside of the welded portion or diffusing it into the melted base material, the synthetic resins of the film base material are welded to each other, thereby making it possible to ensure reliable welding.

In other words, according to the present invention, the overlapping portion of the adhered film is heated with a hot knife, and at the same time, vibration is applied to the adhered film in a direction orthogonal to the pressing direction through the hot knife, so that the welding surface of the adhered film is heated. By creating a minute sliding movement between the welding surfaces, intervening substances that inhibit welding between the welding surfaces are eliminated, complete welding is achieved, and peeling is prevented.

(F) Example An example of the side seal bag-making welding part of the present invention will be described in detail with reference to the drawings. This figure shows a bag-making machine that manufactures a side-seal type bag body 2 with the treated surface as the inner surface, and is composed of a supply section b, a conveyance section c, a welding section d, and a machine stand e.

In the supply section b, the film 3 is unwound from the raw roll 1, and the fold with the anti-fogging surface facing inside is bent in the transport direction to form upper and lower films 15, 15', and the bottom part of the bag body 2 is folded. , and the left conveying section c
The meandering of the film 3 is corrected in the transport section c, the tension of the film 3 and the transport timing are adjusted, and the film 3 is intermittently fed to the welding section d by the width of the bag body 2.

The welding part d has vertically slidable left and right rods 11 and 11' erected on both sides of the film 3 transport path, and a support frame 9 is constructed on the upper ends of the rods 11 and 11'. A hot knife 5 is connected to the lower surface of the film 9 via an insulator 8 so that the blade line of the knife 5 is orthogonal to the direction in which the film 3 is conveyed.

The hot knife 5 is made of metal and has an approximately pentagonal cross-section with an edge 6 formed at the bottom, and an electric heater 7 for heating the knife 5 to about 300° C. is built into the knife 5.

In particular, the vibrator 1 is mounted on the upper surface of the support frame 9.
0 are arranged in series with their vibration directions perpendicular to the conveying direction of the film 3, and the vibrator 10 is configured so that the edge 6 of the hot knife 5 is slightly vibrated in the direction of its blade line by the vibration of the vibrator 10.

Further, a pressure roller 13 whose outer peripheral surface is lined with silicone rubber having heat resistance and appropriate elasticity is disposed below the hot knife 5, and the film 3 is sandwiched between the roller 13 and the hot knife 5. It is configured to press.

Note that the hot knife 5 is intermittently moved up and down by an interlocking mechanism 12 provided on the machine base e.
The pressure receiving roller 13 stops rotating when the film 3 is pressed by an intermittent interlocking mechanism 14 provided on the machine base e.
When the film 3 is conveyed, it is rotated to the left.

On the left side of the welding part e, there are provided upper and lower conveyors 16 and 16' for carrying out the bags 2 manufactured in the welding part d.

Then, the upper and lower films 15, 15', which have been folded in half with the anti-fogging treated side inside in the conveying section C, are placed between the edge 6 of the hot knife 5 heated to about 300° C. and the pressure roller 13 at the welding section d. While applying pressure and heating, the hot knife 5 is vibrated by the operation of the vibrator 10, and each film 15,1 is
The resin constituting 5' is melted into a fluid state, and the molten resin is bonded and integrated to bond the upper and lower films 15, 15', and the upper and lower films 15, 15 protrude to the left of the welded part d. The ends of the films 15, 15' are pinched and pulled to the left by the upper and lower conveyors 16, 16', and the welded portions of the films 15, 15' are separated.

Note that the upper and lower films 15, 15' of the tip edge 17 of the cut-off part have already been welded by the previous operation of the welding part d, so the cut-off part is formed into an individual side-seal type bag body 2. has been
The bags 2 are conveyed to the bag holder 18 by the upper and lower conveyors 16, 16', and the bags 2 are manufactured by repeating this operation.

In particular, in the present invention, when welding the upper and lower films 15, 15, the vibration of the hot knife 5 and the pressure receiving roller 13 is used in combination with the pressure heating by the hot knife 5 and the pressure receiving roller 13.
The same vibration is transmitted through the edge 6 to the welded surfaces of the upper and lower films 15, 15', which are layered with the anti-fog treated surface inside, and the welded surfaces of the same films 15, 15' are caused by minute lateral sliding between each other. By removing the antifogging agent present on the welding surface, the synthetic resin layer serving as the base material of the film 3 can be welded.

The synthetic resin film that is the material of the bag 2 has a thickness of at least 15 μm, whereas the antifog coating has a thickness of several nanometers.
From the melted welded portion of the synthetic resin base material of the upper and lower films 15, 15', the antifogging agent is pushed out to the outside of the welded portion by pressing and heating the approximately linear edge 6, or into the melted base material. By diffusing, the synthetic resins of the film base material are welded to each other, making it possible to ensure reliable welding.

Further, even if the vibrator 10 is constructed so that its vibration direction coincides with the transport direction of the film 3, the same functions and effects as in this embodiment can be obtained.

According to the present invention, the layered portion of the adhered film is heated with a hot knife, and at the same time, vibration is applied to the adhered film in a direction perpendicular to the pressing direction through the hot knife, thereby increasing the welding surface between the welding surfaces of the adhered film. By causing a minute sliding movement between the welding surfaces, intervening substances that inhibit welding between the welded surfaces are eliminated, and complete welding is achieved, thereby preventing peeling.

[Brief explanation of the drawing]

Figure 1 is a side view of the entire bag making machine. Figure 2 is a front view of the main parts. FIG. 3 is a sectional view of the main part. A: Bag making machine, d: Welding part, 5: Hot knife,
10: Vibrator, 13: Pressure receiving roller, 1
5, 15': Upper and lower films.

Claims (1)

[Claims] 1. The upper and lower synthetic resin films 15, 15', which are double layered by folding the folds in the conveying direction, are heated under pressure with a hot knife 5, and the upper and lower synthetic resin films 15, 15' are pressed in the pressing direction through the knife 5. A method for welding synthetic resin films, which comprises fusing them at predetermined intervals by applying vibration in a direction orthogonal to the direction of the film, and simultaneously welding the side edges of the upper and lower films 15, 15 formed by the same fusing.