JPH0698676B2 - Blow molding method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a blow molding method, and more particularly, to a blow molding method in which a film is attached to an outer peripheral surface of a molded product simultaneously with molding.

[Prior Art] As is well known, for example, in a fuel tank of a vehicle,
In order to reduce the manufacturing cost, increase the capacity relatively easily, and realize the weight reduction, the conventional press-formed steel sheet was replaced with one integrally formed by welding, and the strength characteristics required for the tank were changed. It is common practice to form a tank by using a resin, such as polyethylene, which has a relatively low cost and is excellent in moldability.

However, in the above resin tank, there is a problem that fuel such as gasoline stored inside the tank permeates the tank wall and leaks to the outside of the tank while being used for a long period of time. There is a problem in that the weather resistance is deteriorated by receiving the heat.

Therefore, conventionally, by sticking a liquid-impermeable film on the outer peripheral surface of the tank, it is possible to prevent the leakage of fuel to the outside of the tank through the tank wall surface and the deterioration of the weather resistance of the tank. Has been done.

By the way, when molding a hollow article such as a fuel tank of a vehicle using a resin as a raw material, a so-called blow molding method is generally used. This blow molding method is a method of extruding or injecting a thermoplastic resin material into a tube shape or
Preform into a sheet of sheets, and immediately press this softened preform (parison) with a mold to obtain the outer shape of the molded product, blow compressed air into the parison,
It is a molding method that forms a hollow product by inflating the parison along the molding surface of the mold and cooling and solidifying it, which has great practical advantages such as high productivity and low manufacturing cost. .

Then, in the blow molding method, in order to make use of its high productivity, various ideas have been made to attach a film to the outer peripheral surface of a molded article at the same time as molding, not post-processing, and, for example, an adhesive layer It is well known how to set the film that has it in the mold and use the heat of the parison by pressing the film against the parison during blow molding to fuse the adhesive layer and attach the film. (See, for example, JP-A-61-89025).

Further, in order to supply a film between the mold and the parison in the above method, for example, in Japanese Patent Application No. 61-154500, the film is taken out by a molded product removing device for removing the molded product from the mold after blow molding. Is provided with a holding section for holding
A plastic tank molding apparatus has been proposed in which a film can be supplied with a relatively simple structure by reciprocating the holding part between the inside and outside of the mold.

However, the above-mentioned molding apparatus has a problem that the cycle time becomes long because a step of setting a film is additionally required in addition to the steps of blow molding and taking out a molded product.

In order to solve the above-mentioned problem, for example, it is conceivable that a film roller in which a film is stored in a roll shape is provided on a rotating roller, and the film roll is rotated to automatically and continuously supply the film.

Hereinafter, a conventional example in which a film is supplied using this film roll will be described.

As shown in FIG. 5, the blow molding apparatus according to the conventional example described above.
The 51 is equipped with two film rolls 53a, 53b behind the molds 52a, 52b on the side opposite to the direction in which the molded products are taken out.
Two take-up rollers 54a, 54 in front of the molded product take-out side
equipped with b. The film rolls 53a, 53b are provided with films 55a, 55 for sticking to the outer peripheral portion of a molded product (not shown).
b are stored respectively, and the films 55a and 55b are wound by the winding roller 54a that cooperates with the film roll 53a and the winding roller 54b that cooperates with the film roll 53b while keeping them substantially parallel to each other. It has become.

At the end of each molding cycle, the films 55a and 55b are wound up by a predetermined length, and the succeeding films 55a and 55b are automatically and continuously fed to the molds 52a and 52b and the parison 56.
And supplied respectively.

[Problems to be Solved by the Invention] However, in the above conventional method, two film rolls are used.
Since two winding rollers 54a and 54b are required for 53a and 53b, there is a problem that the apparatus becomes complicated.

[Object of the Invention] The present invention has been made to solve the above-mentioned problems, and when a molded product is taken out of a mold, the film is automatically moved by using the movement to pull out a subsequent film. An object of the present invention is to provide a blow molding method that can be supplied to a mold dynamically and continuously and that can simplify the structure of the apparatus.

[Means for Solving the Problems] Therefore, according to the present invention, a film roll having a film stored therein is rotatably provided on the side of the mold opposite to the take-out side of the molded product, and the film roll is rotated by the above-mentioned mold. In a blow molding method in which a film is automatically supplied between a parison and the film is attached to the outer peripheral portion of the molded product at the same time as molding, when the molded product is taken out of the mold after the blow molding, By removing the molded product from the mold by continuing the film part on the non-molded product take-out side following the film part attached to the outer periphery of the molded product and the film sticking part for the molded product of the next cycle Pull the film in the direction in which the molded product is taken out, rotate the film roll, and pull out the subsequent film stored in the film roll into the mold. It is obtained so as to feed.

[Effect of the Invention] According to the present invention, when the molded product is taken out from the mold after the completion of blow molding, the film part on the non-molded product take-out side following the film part attached to the outer peripheral part of the molded product, Continuing the film pasting part to the molded product of the next cycle, pulling the film from the mold by pulling the film in the molded product removal direction, rotating the film roll, the subsequent film stored in the film roll Since the film is pulled out, the film can be automatically and continuously supplied into the mold, and
Since it is not necessary to provide a take-up roller as in the past,
The structure of the device can be simplified.

[Embodiment] An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

As shown in FIG. 3, the blow molding apparatus 1 according to the embodiment of the present invention is symmetric with respect to the center line of the parison 2 and an accumulator head 3 that extrudes as a parison 2 by using a heat-melted thermoplastic resin as a base material. A pair of metal molds 4, 4 located at, a blow pin 5 for blowing compressed air into the parison 2, and a molded product 16 from the molds 4, 4 after blow molding.
And a molded product takeout device 7 for taking out the molded product.

The molded product take-out device 7 has one end fixed to the frame 8 of the blow molding device 1 and extends in a direction (front-back direction) perpendicular to the opening / closing direction (horizontal direction) of the molds 4, 4 and the other end. Is provided with a take-out section 12 slidably provided along a guide rail 11 fixed to the column 9, and a chain drive section 13 for sliding the take-out section 12. The take-out portion 12 is provided in parallel with the guide rail 11 and includes a pair of arms 15 and 15 opened and closed by cylinders 14 and 14, as shown in FIG.

Further, the blow pin 15 is held by a vertical driving device (not shown) at a rising position where the tip end portion is located inside the parison 2 during blow molding, and when the molded product 16 is taken out after the blow molding is completed, Molded tip
It is adapted to be held in a lowered position below the lower end surface of 16.

By the way, the blow molding apparatus 1 according to the present embodiment includes the mold 4,
Between the 4 and the parison 2, two film rolls 22 and 22 are provided for automatically and continuously supplying the film 17 to be attached to the outer peripheral surface of the molded product 16. As shown in FIG. 1, the film rolls 22, 22 are provided behind the dies 4, 4 on the opposite side of the molded product take-out device 7 and fixed to the bed portion 8a of the frame 8 of the blow molding device 1. A shaft
It is possible to freely rotate around 22a, 22a.

The film rolls 22 and 22 are rolls of the films 17 and 17, and can be fed into the molds 4 and 4 by rotating them in a predetermined direction. ing. That is, as shown in FIG. 1 and FIG. 3, after the blow molding is completed, the molded product 16 is taken out from the molds 4 and 4 by the molded product take-out device 7 using the molds 4 and 4, and the film 17 is formed. The film portion 17a (hereinafter referred to as an extension) on the non-molded product take-out side subsequent to the portion attached to the outer peripheral surface of the product 16 is pulled, so that the film rolls 22,2
2 rotates, the films 17 and 17 are automatically supplied into the molds 4 and 4, and the sticking portions 17b and 17b are set.

Further, preferably, as shown in detail in FIG. 2, on the inner surface of the molds 4, 4, there are cut-off portions 23, 23 for cutting the films 17, 17 in the vicinity of the end portion close to the molded product removing device 7. Are provided, the films 17 and 17 are cut at the cut-off portions 23 and 23 when the left and right dies 4 and 4 are closed during blow molding.

Regarding the method of molding a molded product in which a film is attached to the outer peripheral surface using the blow molding device 1 configured as described above, a table showing the relationship between the process sequence and the operation of each component is
This will be described below.

First, in step # 1, the arm provided with the upper end of the blow-molded molded product 16 in the removal part 12 of the molded product removal device 7
The molded product 16 is taken out from the opened molds 4 and 4 by retracting the take-out portion 12 toward the molded product take-out side while being held by 15,15. At this time, since the extension portion 17a of the film 17 attached to the outer peripheral portion of the molded product 16 is also pulled backward at the same time, the film roll 22,22 rotate, the films 17,17 are automatically supplied into the molds 4,4, and the attachment parts 17b, 17b of the films 17,17 are set (see FIGS. 1 and 3).

Next, in step # 2, the parison 2 made of a thermoplastic resin as a base material is preformed by the accumulator head 3 and extruded between the films 17 and 17, and the blow pin 5 has a tip end portion of the parison 2. Is set so as to be located inside the container (see FIGS. 1 and 3).

Next, in process # 3, the molds 4 and 4 are closed. At this time,
The films 17 and 17 are cut-off portions 23 and 2 provided on the molds 4 and 4, respectively.
It is cut at 3 (see Fig. 2).

Subsequently, in step # 4, compressed air is blown into the parison 2 from the blow pin 5 to start blow molding. As a result, the film 17 that was in contact with the outer peripheral surface of the parison 2 in step # 3 is moved along the molding surface of the molds 4 and 4 to the parison 2
Affixed to the outer peripheral surface of. Also, at this time, process # 1
Then, the arms 15 and 15 of the take-out portion 12 that has retracted by holding the molded product 16 are expanded to open the upper end of the molded product 16 and place the molded product 16 in place.

Then, during the blow molding, the take-out portion 12 is advanced to the molds 4, 4 side in step # 5.

Next, in step # 6, the blow molding for a predetermined period is completed, and at the same time, the arms 15 and 15 of the take-out portion 12 are closed and the upper end of the molded product (not shown) for the next cycle is held.

Next, in step # 7, the molds 4, 4 are opened, and at the same time, the blow pin 5 is lowered to a lowered position in which the tip end thereof is located below the lower end of the molded product (not shown) in the next cycle.

Next, in step # 8, the take-out section of the molded article take-out device 7
12 is retracted to the molded product removal side.

In this process # 8, the same process as the process # 1 is repeated, and the films 17 and 17 are supplied again from the film rolls 22 and 22 and set in the molds 4 and 4 (see FIGS. 1 and 3). See figure).

As described above, according to the present embodiment, when the molded product 16 is taken out from the molds 4, 4 after the completion of blow molding, the anti-molding that follows the film portion attached to the outer peripheral portion of the molded product 16 is performed. The film part 17a on the product take-out side and the affixing parts 17b, 17b of the films 17, 17 for the molded product (not shown) for the next cycle are made continuous, and the molded product 16 is taken out from the molds 4, 4 to form the film 17 , 17 is pulled in the direction of taking out the molded product, the film rolls 22, 22 are rotated, and the subsequent films 17, 17 stored in the film rolls 22, 22 are pulled out. It is possible to continuously supply into the molds 4 and 4, and since it is not necessary to provide the winding rollers 54a and 54b as in the conventional case, the structure of the device can be simplified.

Further, in the present embodiment, preferably, the cutting portions 23, 23 for cutting the films 17, 17 are provided in the vicinity of the end on the molded product taking-out side of the inner surfaces of the molds 4, 4, and at the time of blow molding, the metal mold is used. Type
When the 4 and 4 are closed, the films 17 and 17 are automatically cut at the molded product take-out side, so after blow molding, a continuous film between the molded product of the previous cycle (not shown) The step of cutting can be omitted, and the molding cycle time can be shortened.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an essential part of a blow molding apparatus according to an embodiment of the present invention as seen from above, and FIG. 2 is a cross-sectional view of a mold of a blow molding apparatus according to the embodiment of the present invention. FIG. 3 is a front view schematically showing the overall structure of a blow molding apparatus according to an embodiment of the present invention, and FIG. 4 is an explanatory view showing a take-out portion of a molded product take-out apparatus according to an embodiment of the present invention as seen from above. Figure, fifth
FIG. 1 is an explanatory view schematically showing a main part of a blow molding device according to a conventional example. 2 ... Parison, 4 ... Mold, 7 ... Molded product take-out device, 16 ... Molded product, 17 ... Film, 17a ... Unmolded product take-out side film part, 17b ... Film pasting part, 2
2 ... Film roll.

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Claims (1)

[Claims] 1. A film roll containing a film is rotatably provided on the side of the mold opposite to the side where the molded product is taken out, and the film is automatically supplied between the mold and the parison by rotating the film roll. In a blow molding method in which the film is attached to the outer peripheral portion of the molded article at the same time as molding, the film portion attached to the outer peripheral portion of the molded article when the molded article is taken out of the mold after the blow molding is completed. Continuing with the film part on the side opposite to the molded product take-out side and the part where the film is attached to the molded product in the next cycle, pull the film out of the mold and pull the film in the direction of taking out the molded product. The blow molding is characterized in that the film is rotated and the subsequent film stored in the film roll is pulled out and supplied into a mold. Shape method.