JPH0760829A - Method and apparatus for thermally molding resin product - Google Patents

Abstract

PURPOSE:To provide a method and an apparatus for thermally molding a resin product with high productivity in which a thermally molding operation is facilitated. CONSTITUTION:Blank heating and transferring means 12 and a resin product molding means 13 are separately provided. Blanks 16 are fed from a blank supply unit 17 to a blank holder 15 provided on an outer periphery of a first rotor 14 one by one, and the blank 16 held by the holder 15 is heated by a heater provided near the rotor 14 upon rotation of the holder 15. Then, the blank 16 held by the holder 15 is separated by a blank separating unit 22, supplied to a resin product molding means 13, and thermally molded to a vessel 27 by molds 25 provided around a second rotor 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoforming method for a product made of a thermoplastic resin and an apparatus for the same, and can be used for thermoforming a food container, for example.

[0002]

BACKGROUND ART AND PROBLEMS TO BE SOLVED BY THE INVENTION For example,
In the thermoforming technology for containers, many thermoforming technologies using blanks (preformed blanks or pre-cut blanks) that do not generate scrap have already been proposed as opposed to thermoforming technology for sheets that generate a large amount of scrap. There is. However, the conventional thermoforming technique using a blank has merits and demerits in terms of productivity, operability, apparatus scale, price, and the like, and a method satisfying both of them has not been proposed yet.

For example, a thermoforming technique using a preformed blank is one in which a preformed blank is molded by injection molding and then pressure-molded. Although the apparatus can be downsized, the productivity is extremely high. It is low and it is difficult to mold a container made of a multilayer sheet. A thermoforming technique using a pre-cut blank is disclosed in, for example, JP-A-1-103424.
As proposed in Japanese Patent Publication, a conventional thermoforming machine is provided with blank holding means and transfer means, and after the blank is supplied, thermoforming is carried out. Inevitably, the price will be high.

The SFP according to Japanese Patent Publication No. 57-1415
According to the technology that uses a preformed blank by pressing a pre-cut blank as in the (scrapless forming process), the formed sheet is cut into a rectangular shape, and this is pressed and compressed to form a predetermined blank. After that, it is thermoformed, but the number of steps is increased, which complicates the apparatus, increases the cost, and is difficult to operate. Therefore, it is an object of the present invention to provide a thermoforming method for a resin product and an apparatus for the same, which has high productivity and facilitates thermoforming operation.

[0005]

A method for thermoforming a resin product according to the first aspect of the present invention is a rotary blank heating / transferring means having a blank holding portion and a blanking portion,
A rotary resin product forming means having a die around the same is arranged separately from each other, and in the blank heating / transfer means, a blank is held from a blank supply section around a first rotating body. The blank held by the blank holding section is heated by a blank heating means provided in the vicinity of the first rotating body along with the rotational movement of the blank holding section, and then the blank is removed by the blank removing section. The blank held by the blank holding portion is detached and supplied to the resin product molding means. On the other hand, in the resin product molding means, the molding die provided around the second rotating body is After receiving the blank from the blank holder, the blank mounted on the molding die is thermoformed into a resin product.

The resin products include various containers, parts, household sundries and the like. The type of the resin may be a commonly used thermoplastic resin, for example, polypropylene, polystyrene, polyethylene terephthalate,
There are polyvinyl chloride, etc. The blank may be a precut blank or a preformed blank. The shape and thickness of the blank are determined by the flange shape of the resin product, the drawing ratio, and the like.

In the case of a pre-cut blank, a film or sheet (single layer, multi-layer) punched into a predetermined shape is used. Compared with thermoforming from a sheet, the blank interval and the like can be minimized at the time of punching, and it is possible to efficiently collect and at the same time it is advantageous for recycling punch loss. The thermoforming method can be carried out by a conventional method, but it is necessary to use a so-called preceding clamp method in which the peripheral edge portion of the blank is pressed before forming. The shaping force at the time of thermoforming may be only vacuum, only compressed air, or combined use of vacuum and compressed air. The plug assist molding is used when the drawing ratio is large. The molding die is cooled if necessary.

In a thermoforming apparatus for resin products according to a second aspect of the present invention, a blank heating / transporting means and a resin product shaping means are provided separately, and the blank heating / transporting means is the first Rotating body, a blank holding portion that is provided around the first rotating body and holds a blank, a blank releasing portion that releases the blank from the holding state of the blank, and a blank that sends the blank to the blank holding portion. It has a supply part and a blank heating means provided along the rotation trajectory of the blank holding part, and the molding means for the resin product is provided on the second rotating body and around the second rotating body. And a molding die formed as described above.

The rotation axis of the first rotating body and the rotation axis of the second rotating body may be provided in parallel, or may be provided in a non-parallel intersecting state. The blank heating means is composed of a normal indirect heating device such as an infrared heater. A third invention of the present invention is characterized in that the blank holding portion has an opening into which the blank is inserted, and a groove with which the blank is engaged is formed on an inner peripheral surface of the opening. And A fourth aspect of the present invention is characterized in that the blank releasing section includes a blank pushing mechanism for pushing out the blank held by the blank holding section.

According to a fifth aspect of the present invention, a guide portion for arranging the blank at a fixed position is formed in the molding die in the vicinity of the cavity, and a pin for holding the blank has a peripheral portion of the cavity. It is characterized by being installed upright. The blank is held in the molding die while being pierced by the pins. The height of the pins depends on the thickness of the blank, but may be, for example, about 1 mm, and the number of pins may depend on the weight of the blank, but may be set to a number that can prevent the pins from falling off, for example, 2 to 4. .

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A thermoforming method for resin products and an apparatus used in this thermoforming method according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 and 2, the thermoforming apparatus 11 of this embodiment has a blank heating / transfer means 12 and a resin product forming means 13, and these 12 and 13 are arranged separately. . The blank heating / transfer means 12 includes a first rotating body 14, a plurality of blank holding portions 15 and a blank removing portion provided along the outer peripheral surface of the first rotating body 14.
22, a blank supply unit 17 for feeding the blank 16 to the blank holding unit 15, a blank pushing unit 18, and the blank 16
And a blank heating unit 19 for heating the same.

The first rotating body 14 has a rotating shaft 21 at the center thereof, which is connected to a rotation driving means such as a motor.
As shown in FIGS. 3 and 4, the blank holding portion 15 has a circular opening 15A into which the blank 16 is inserted, and the inner peripheral surface of the opening 15A has a V-shape with which the blank 16 is engaged. A V-shaped groove 15B is formed. Also, near the upper end of the opening 15A, make a slight taper so that the blank 16 can be easily inserted.
15C is formed. Then, the blank holder 15
Are fixed to the first rotating body 14 via the legs 15D.

The blank release section 22 has the opening 15A.
A tubular portion 22A that is inserted through the inside to push up the blank 16, a base portion 22B of the tubular portion 22A, and a rod 22C that is provided below the base portion 22B and that is connected to an air cylinder or the like and is movable back and forth.
Is equipped with. The blank holding portion is provided on the base portion 22B.
A hole 22D is formed through which the leg 15D, which also serves as a guide when the 15 moves up and down, is inserted. This blank release section 22
In the cylindrical portion 22A of the
Suction cup 23 for picking up one by one in the blank holder 15
Is provided. The suction cup 23 is configured to be movable back and forth by an air cylinder or the like. The base portion 22B has a hole portion 22E through which the suction cup 23 is advanced and retracted.
Are formed.

As shown in FIGS. 1 and 2, the blank supply section 17 is provided with a guide 17A for the blank 16 and a heater 17B provided along the guide 17A. The blank pushing portion 18 includes a rod 18A which can be moved forward and backward by an air cylinder or the like, and a blank pushing ring 18B attached to the tip of the rod 18A.
The blank heating unit 19 is composed of an infrared heater 19A,
It is provided in a circular shape in the vicinity of the rotation trajectory of the blank holder 15.

As shown in FIGS. 1, 2 and 9, the resin product molding means 13 includes a second rotary member 24 and a second rotary member 24.
It is configured by including three molding dies 25 provided at equal intervals on the outer peripheral surface, a clamp (compressed air chamber) 27 provided with a plug 26, and the like. The second rotating body 24 has a rotating shaft 28 at the center, which is connected to a rotation driving means. The rotary shaft 28 and the rotary shaft 21 of the first rotary body 14 are in a parallel positional relationship, and the rotary shafts 21 and 28 are arranged such that the blank separating portion 22 extends as shown in FIGS. The blank 16 is separated from the mold 25 so that the blank 16 can be supplied to the mold 25.

Each of the molds 34, as shown in FIGS.
A cavity 29 is formed in a concave shape corresponding to a predetermined container, and a horizontal peripheral edge portion 31 having a slightly larger diameter than the cavity 29.
Are formed. For example, in this peripheral portion 31, 4
Book pins 32 are erected at equal intervals to hold the blank 16. The height of each pin 32 is, for example, 0.2 mm.
Each mold 25 has a water cooling type cooling function. And
A guide portion 25A for arranging the blank 16 at a fixed position is formed continuously with the peripheral edge portion 31. A plurality of vacuum suction holes 33 are formed at the bottom of each mold 25.
Communicate with the vacuum pump through the inside of the second rotating body 24.

As shown in FIGS. 9 and 10, the clamp 27 has a hole 35 and a compressed air port 36 through which the rod 34 of the plug 26 moves forward and backward, as shown in FIGS. The outer diameter of the clamp 27 has a peripheral edge portion of the mold 25 so that the clamp 27 can press the end edge portion of the blank 16 held by the mold 25.
It is slightly smaller than the diameter of 31. This plug 26
It can be moved back and forth by an air cylinder, etc., and is used when the throttle ratio is large.

Next, a method of thermoforming a resin product using the thermoforming device 11 will be described. First, as shown in FIGS. 1 and 4, in the blank heating / transfer means 12, the suction cup 23
The blanks 16 are taken one by one from the blank supply unit 17 and placed on the taper 15C portion of the opening 15A of the blank holding unit 15. The blank 16 is a disc-shaped product obtained by cutting a polypropylene resin sheet with a punching blade, and has a thickness of 1.5 mm and a diameter of 86 mm, for example.

Next, as shown in FIGS. 2 and 5, the first rotating body 14 is slightly rotated to bring the blank holding portion 15 to the position of the blank pushing portion 18, where the blank pushing portion 18 is placed.
Rod 18A extends downward to push the blank 16 into the groove 15B of the blank holding portion 15, and the blank 16 is engaged with the groove 15B. Subsequently, as shown in FIGS. 1, 2, and 6, the first rotating body 14 is rotated, and the blank 16 held by the blank holding section 15 is rotated by the rotation of the first rotating body 14 to remove the blank 16 from the blank heating section 19. It is heated by the heater 19A. As the heating conditions, for example, the surface temperature of the blank 16 is 185 ° C. and the time is 1
7 seconds.

Next, as shown in FIGS. 2, 3 and 8, when the first rotating body 14 rotates and the blank holding section 15 reaches the resin product molding means 13, the rotation is temporarily stopped. Here, the blank release section 22 extends upward and pushes out the blank 16 held by the blank holding section 15 so as to be released from the groove 15B, and then the blank 16 is placed on the upper end of the blank release section 22 and the blank 16 is removed. Edge 31 along the guide 25A of the mold 25
Press against. Then, the blank 16 is held in the mold 25 by piercing the end portion of the blank 16 into the pin 32.
At this time, the temperature of the blank holder 15 and the mold 25 is adjusted to about 30 ° C.

Next, as shown in FIGS. 2, 9 and 10, when the second rotating body 24 rotates and the die 25 reaches the position of the clamp 27, the rotation is temporarily stopped, and the clamping is performed here. 27, the clamp 16 moves the blank 16 to the peripheral edge 31 of the mold 25.
Hold it down. Subsequently, the blank 16 is pressed into the mold ² by plug-assisted pneumatic molding (compressive aerodynamic force, for example, 3 kg / cm ² ).
Shape according to the shape of cavity 5 of 5. Next, FIG.
As shown in, after rotating the second rotary body 14 by 120 degrees,
The molded container 37 is taken out of the mold 25.

The container 25 obtained according to this embodiment has an appearance,
Good mold reproducibility and wall thickness distribution, and 130
It had heat resistance such that it was not deformed by heating at ℃ for 30 minutes. According to this embodiment, blank heating / transfer means
The blank 16 is heated, the blank 16 is supplied to the mold 25, and the blank 16 is transferred to the container 37 in accordance with the rotation of the first and second rotating bodies 14 and 24 provided on the resin 12 and the resin product molding means 13. Because the process such as thermoforming of is performed continuously,
Productivity is high.

Further, since the steps of heating the blank 16 and supplying the blank 16 to the mold 25 are automated,
It does not take time and the thermoforming operation is extremely easy. Further, since the blank 16 is held by the blank holding portion 15 by the groove 15B and the blank 16 is held by the mold 25 by the pin 32, the first and second rotating bodies 14, 2 are
Even if the blank 16 rotates with the rotation of 4, the blank 16 does not fall off. Then, the removal of the blank 16 held by the blank holding unit 15 and the supply to the mold 25 are reliably performed by the movement of the blank removing unit 22.

Further, a blank heating device having a heater 19A
In addition to the transfer means 12 and the resin product molding means 13 being rotatable, the directions of the rotation shafts 21 and 28 of the first and second rotating bodies 14 and 24 can be set arbitrarily. The device 11 can be assembled according to the space where the device 11 is installed. As a result, the device can be downsized and the space can be saved. In the above example, during thermoforming,
Although the plug-assisted pressure forming is performed, vacuum-pressure forming or plug-assisted vacuum forming may be used depending on the thickness of the blank 16 and the like.

[0025]

According to the thermoforming method for a resin product and the apparatus according to the present invention, a rotary type blank heating / transfer means having a blank holding portion and a detaching portion, and a rotary type blank die having a die around it. Since the molding means for the resin product is disposed separately from each other and each step in the thermoforming is continuously performed, the productivity is increased and the thermoforming operation is facilitated. In this device, a groove for engaging the blank is formed on the inner peripheral surface of the opening of the blank holding portion, and a pin for holding the blank is provided upright on the peripheral edge of the cavity of the molding die. Therefore, the first and second
Even if the blank rotates with the rotation of the rotating body, there is no possibility that the blank will fall off. In addition, the movement of the blank separating section can surely separate the blank held by the blank holding section and supply it to the mold.

[Brief description of drawings]

FIG. 1 is a front view of an apparatus used in a thermoforming method for resin products according to an embodiment of the present invention.

FIG. 2 is a front view of the entire apparatus according to the present embodiment.

FIG. 3 is a cross-sectional view of a blank holding portion and a blank detaching portion according to this embodiment.

FIG. 4 is a cross-sectional view showing a method of supplying a blank to a blank holding portion.

FIG. 5 is a cross-sectional view of a blank holding unit and a blank pushing unit.

FIG. 6 is a cross-sectional view of a blank holding unit and a blank heating unit.

FIG. 7 is a cross-sectional view of a blank holder and a mold.

FIG. 8 is a cross-sectional view of a blank removing part and a mold.

FIG. 9 is a cross-sectional view of a mold and a clamp.

FIG. 10 is a cross-sectional view of a mold and a clamp.

[Explanation of symbols]

 11 Thermoforming device 12 Blank heating / transfer means 13 Resin product forming means 14 First rotating body 15 Blank holding section 15A Blank holding section opening 15B Blank holding section groove 16 Blank 17 Blank supply section 18 Blank pushing section 19 Blank heating part which is a blank heating means 19A heater 22 Blank removal part 23 Suction cup 24 Second rotating body 25 Mold for molding 26 Plug 27 Clamp 29 Cavity 31 Peripheral part 32 Pin 37 Container made of resin product

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kosaburo Matsuzawa 2-27-2 Hiromichi Hiromichi, Adachi-ku, Tokyo Matsuzawa Manufacturing Co., Ltd.

Claims (5)

[Claims] 1. A rotary type blank heating / transfer means having a blank holding part and a separating part, and a rotary type resin product molding means having a die around it are arranged separately from each other, and the blank heating / transfer means In the transfer means, the blank is fed from the blank supply unit to a blank holding unit provided around the first rotating body, and the blank held by the blank holding unit is moved by the first holding unit with the rotational movement of the blank holding unit. 1 is heated by a blank heating means provided in the vicinity of the rotating body, and then the blank held by the blank holding portion is released by the blank releasing portion and supplied to the resin product forming means. In the molding means of the product, the molding die provided around the second rotating body receives the blank from the blank holding portion, and thereafter, places it in the molding die. Thermoforming method of the resin product characterized in that the blank kicked thermoforming the resin product. 2. A blank heating / transporting unit and a resin product molding unit are separately provided, and the blank heating / transporting unit is provided around the first rotating body and the first rotating body. A blank holding part provided to hold a blank, a blank releasing part for releasing the blank from the holding state of the blank, a blank supply part for feeding the blank to the blank holding part, and a rotation trajectory of the blank holding part A blank heating means provided, and the molding means for the resin product is a second rotating body and a second rotating body.
And a molding die provided around the rotating body. 3. The blank holder has an opening into which the blank is inserted, and a groove with which the blank is engaged is formed on an inner peripheral surface of the opening. Item 2. A thermoforming apparatus for resin products according to item 2. 4. The thermoforming apparatus for a resin product according to claim 2, wherein the blank removing section includes a blank pushing mechanism for pushing the blank held by the blank holding section. 5. The molding die has a guide portion for arranging the blank at a fixed position formed in the vicinity of the cavity, and a pin for holding the blank provided upright on a peripheral portion of the cavity. The thermoforming apparatus for resin products according to claim 3 or 4, wherein