JPH06226834A - Production of container from thermoplastic foamed resin sheet - Google Patents

Abstract

(57) [Summary] [Structure] The upper and lower point clamps 30 and 40 minimize the plasticized thermoplastic foamed resin sheet S at the boundary between individual molds of a plurality of male and female molds 10 and 20, respectively. Clamp it by pinching on. After this, male and female molds 10, 20
Close and mold. [Effect] It is possible to manufacture a molded product in which the amount of drawing in a large number of deep drawing can be increased, the reproducibility of fine printing and the fixed position printability are excellent for each container, and the wall thickness is sufficiently secured. It is possible to uniformly and stably pull in the sheet during molding, and it is possible to manufacture a good molded product in terms of uniform thickness and outer shape stability and dimensional stability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a container from a thermoplastic foamed resin sheet, and more particularly to a method for producing a container from a thermoplastic foamed resin sheet by deep-drawing in multiple steps. The present invention relates to a method capable of producing a container having excellent reproducibility of fine printing and printability in a fixed position and having a sufficient thickness.

[0002]

2. Description of the Related Art Conventionally, as a method for manufacturing a container or the like, various vacuum forming methods and the like have been adopted for thermoplastic foamed resin sheets. However, in either method, when the sheet is a continuous sheet, when the sheet is a continuous sheet, it is pierced and clamped by the clamp needles or the like provided on both sides of the feeding means such as a chain belt to perform vacuum forming or the like. Was there. Further, when a sheet cut into a certain length is used, vacuum molding or the like is performed by clamping the four sides of the sheet into a frame shape.

With respect to these clamps, the deeper the shape of a molded product such as a container is, the more a plurality of them are to be taken, the more the female mold and the male mold each have a plurality of individual molds. The resulting container was not uniform in thickness and outer shape, and wrinkles and cracks were generated due to uneven drawing.

Therefore, in order to improve these problems, a manufacturing method for stabilizing the narrowing down during vacuum forming has been proposed (Japanese Patent Publication No. 1-101414). This manufacturing method is a method of continuously manufacturing a large number of deep drawing containers,
Upper and lower molding clamps 80 that can operate independently of the male and female dies and that can clamp the sheet partially or wholly (see FIG. 13) are used to form the upper surface opening diameter and side wall of the molding container. Around the individual molds of the female mold 10 and the male mold, in which the drawing ratio, which is the ratio of the heights, is 1: 0.7 or more,
In this method, the sheet is clamped for each individual mold, and then the mold is closed to perform molding.

[0005]

However, in the above method, as shown in FIG. 13, the rib portion 81 of the forming clamp 80 presses the sheet around the die 10 as a whole, so that the sheet is pulled in. Since it is suppressed and reduced, it is difficult to obtain a sufficiently strong container because the thickness of each manufactured container is thin.

Further, since the deep drawing is performed with such a small drawing amount, the stretching ratio of the sheet is increased, so that fine printing can be reproduced on a molded product or fixed position printing can be performed on each molded product. Was difficult. Therefore, an object of the present invention is to provide a method for manufacturing a container from a thermoplastic foamed resin sheet capable of increasing the amount of drawing in the deep drawing of multiple cavities in order to solve the above problems.

[0007]

In order to solve the above problems, a method for producing a container from a thermoplastic foamed resin sheet of the present invention is a long thermoplastic foamed resin in a plasticized state by heating. A method for continuously manufacturing a large number of deep drawing containers from a sheet with a molding die, wherein the sheet is fed while both sides are clamped by feeding means, and can be operated independently of the male and female dies, Using the upper and lower point clamps that clamp the sheet to a minimum, clamp the sheet at the boundary between the individual female and male molds, and then close the mold to perform molding. It is characterized by.

[0008]

According to the method of manufacturing a container from the thermoplastic foamed resin sheet of the present invention having the above-mentioned structure, regardless of whether the male and female molds are opened or closed at the boundary between the plurality of female and male molds. The upper and lower point clamps that operate independently and pinch the thermoplastic foam sheet to the minimum, when manufacturing a large number of deep-draw molding containers from the thermoplastic foam sheet, do not press the sheet excessively, and this point It can be clamped by a clamp with an appropriate pressing force.

Further, since the upper and lower point clamps clamp the sheet to a minimum at the boundary between the male and female molds, the amount of pulling in the sheet at the time of molding is not suppressed,
And it can be clamped for each individual mold. As a result, it is possible to stably pull in a large amount without restraining the amount of pulling in of the sheet. Furthermore, since it operates independently at the boundary between the female and male molds, each of which consists of multiple parts, independently of the opening and closing of the male and female molds, it is most suitable for deep drawing without being restricted by the opening and closing motions of the male and female molds. It is possible to clamp the sheet comfortably when it is pressed or pressed.

Further, since the sheet is clamped for each individual die at the boundary portion of the die and then the die is closed to perform the forming, in the case of deep drawing of a large number of pieces, the sheet is drawn in at the time of forming. Can be performed uniformly and stably.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a schematic view of an apparatus for use in a method for producing a container from a thermoplastic foam resin sheet according to an embodiment of the present invention. S in FIG. 1 is a thermoplastic foamed resin sheet such as a foamed polystyrene sheet, and is fed from the raw fabric S1 wound in a roll shape. A is a heating means such as a heating furnace provided during the sheet S feeding process,
The sheet S is plasticized before vacuum forming.
B is a vacuum forming apparatus, and the male and female molds 10 and 20 having a drawing ratio of 1: 0.4 or more, which is the ratio of the opening diameter of the upper surface of the molding container to the height of the side wall, and the male and female molds 10 and 20. Independently operable point clamps 30 and 40 are provided so that a molded product C (see FIG. 12) of a container formed by vacuum molding can be sequentially provided. Each of the male and female molds 10 and 20 has a plurality of molds, and can be moved up and down by the cylinder mechanisms 50 and 60.

FIG. 2 is a bottom view of the male and female molds on the female mold side. The arrow in FIG. 2 indicates the sheet feeding direction, and 30 is a point clamp on the female die 10 side, which is made of a rectangular plate and has a female die through hole 32 through which the female die 10 can be inserted. 30a is a point clamp 30
The L-shaped conner ribs are formed on each of the corners, and one rib is attached to each of the corners, for a total of four ribs. 30b is
The point clamp 30 is a T-shaped side rib formed on both sides of the sheet S in the feeding direction and on the front side. Three ribs are provided on each side of the sheet S in the feeding direction, and four ribs are provided on the front side of the sheet S in the feeding direction. A total of 10 are installed. 30c is adjacent to 4
It is a cross-shaped crossing rib formed in the central portion at the boundary of the female through holes 32, and 12 ribs are attached. Reference numeral 30d denotes rod-shaped misalignment preventing ribs formed at a rear portion of the point clamp 30 on the sheet S feeding side, and five ribs are attached to a rear portion of the sheet S in the sheet feeding direction. The deviation of the rear portion of the sheet S during molding is prevented. Although not shown, also in the point clamp 40 on the male die 20 side, a rib 30a for a corner, a rib 30b for a side, a rib 30c for a cross, and a rod-shaped rib 3 similar to the point clamp 30 are provided.
0d and a male through hole into which the male 20 can be inserted are provided.

In this way, the point clamps 30, 40
Is arranged at the boundary between the individual molds 10 and 20 without surrounding the mold periphery, and the sheet S is attached to the ribs 30a to 30d and 40.
Since it is clamped to the minimum by a to 40d, the amount of drawing in at the time of molding can be increased. That is, since the point clamps 30 and 40 clamp the sheet to a minimum, the point clamps 30 and 40 do not suppress the retracted amount of the sheet S and can clamp each sheet individually. Is.

FIG. 3 shows a partially enlarged sectional view of a male and female type,
A female mold 10 and a male mold 20 as a vacuum forming device are shown together with point clamps 30 and 40. Reference numerals 11 and 21 in FIG. 3 denote vacuum suction holes of the female die 10 and the male die 20, respectively, and passages 12, 22 to a vacuum pump (not shown).
Are connected via. 31 and 41 are clamps 30,
40 is a piston rod of each lifting cylinder mechanism 40 (not shown). Clamps 30 and 40 are female mold 10 and male mold 2.
At the boundary between the individual molds of 0, the individual molds are operated independently of the opening / closing operation of the male and female molds 10 and 20, and the seat S can be partially clamped. It is preferable that the ribs 30b, 30c, 40b, 40c of the clamps 30, 40 are formed at the tips of the ribs 30b, 30c, 40b, 40c in an uneven shape so that the sheet S can be easily clamped without slipping.

Next, a process of forming a deep-drawn molded product using the above vacuum forming apparatus will be described. 4 to 11
Is a schematic view showing each step during vacuum forming, and 70 is
It shows a clamp needle portion which is included in a chain belt and other feeding means, and clamps both sides of the sheet S for feeding. In order to manufacture a large number of deep-drawing containers from the thermoplastic foamed resin sheet S, the sheet S plasticized by heating by the heating furnace A or the like in the course of feeding the sheet S is fed by at least both sides. It is fed in a state of being clamped by the clamp needle 70 or the like provided in FIG. 1, and is molded into a container through the molding process shown in FIGS.

First, the plasticized sheet S is brought into contact with the sheet S by lowering the clamp 30 on the side of the female die 10 which is the upper side from the state of FIG. 4 as shown in FIG. Next, the lower male die 20 and the male die 20 side clamp 40 are lifted to the seat S side, and the sheet S is individually attached to the boundary portion between the male and female die 10 and 20 by the clamps 30 and 40. Clamp it as in 6. Further, the male die 20 is further raised to move the seat S to the male die 2
At the same time as starting to squeeze along 0, the female die 10 is lowered toward the seat S to bring the male and female dies closer to each other as shown in FIG. And
The sheet S starts to be drawn into the space between the molds 10 and 20, and the vacuum suction by the molds 10 and 20 is started just before the male and female molds 20 are clamped as shown in FIG. A vacuum molding is performed between the two molds 10 and 20 so as to have a predetermined container C shape. After molding, release the vacuum,
While lowering the male mold 20, the lower clamp 40 is also lowered as shown in FIG. Then, the upper clamp 30 is lifted as shown in FIG.
While ejecting from the side, the female die 10 is raised to complete the demolding of the molded product C as shown in FIG. After the mold release, the plurality of molded products C molded at one time are sent to the next step and sequentially trimmed by the cutting means to be collected as individual molded products C.

As described above, the upper and lower point clamps 3
0 and 40 operate independently of opening and closing of the male and female dies 10 and 20, and ribs 30a to 30d and 40a to 40a are provided at the boundaries between the individual dies of the male and female dies 10 and 20, each of which has a plurality.
Since the sheet S can be clamped to the minimum by d, the point clamps 30 and 40 can clamp the sheet S with an appropriate pressing force.

Further, since the point clamps 30 and 40 operate independently at the boundary between the respective molds of the plurality of male and female molds 10 and 20 independently of the opening and closing of the male and female molds 10 and 20, the opening and closing operations thereof are not performed. Without being restrained, it is possible to clamp the sheet S comfortably at the most suitable time for deep drawing and in the pressed state. Further, in the above method, after the sheet S is clamped at the boundary of the mold for each individual mold,
Since 0 and 20 are closed, the sheet S can be pulled in evenly and stably at the time of molding, which is good in terms of uniform thickness and outer shape stability and dimensional stability. It is possible to realize various moldings, and it is possible to provide a deep drawing container C of good quality.

Furthermore, the point clamps 30, 40
Since the sheet S is clamped to the minimum at the boundary portion between the male and female molds 10 and 20 by using, it is possible to clamp the sheet S without suppressing the retracted amount of the sheet S by the point clamps 30 and 40. Many sheets S can be pulled in. As a result, it is possible to provide the individual containers C that are excellent in reproducibility of fine printing and printability in fixed positions and have a sufficient thickness.

It should be noted that, in practice, the present invention has male and female dies 10, 2.
In some cases, the female mold is maintained at about 60 ° C. and the male mold is maintained at about 80 to 90 ° C. It is convenient to keep the sheet S in the plasticizing temperature state. Further, regarding the male and female molds 10 and 20 and the upper clamp 30, a fluororesin (for example, Teflon) is used.
If the coating is performed, it is convenient for avoiding excessive close contact with the sheet S, preventing obstruction of pull-in during molding of the sheet S, and maintaining easy release.

Further, as the sheet S, in addition to a monolayer body of a foamed polystyrene sheet or other thermoplastic foamed resin sheet, a non-foamed resin sheet or film (for example, high-impact polystyrene sheet, etc.) which may be printed may be used. The same vacuum forming can be performed by using a laminate of Furthermore, point clamp 3
Each of 0 and 40 may be a plate in which a through hole that allows the mold to be inserted is provided in one of the upper and lower sides.

The point clamps 30 and 40 may be such that the ribs 30a to 30d and 40a to 40d are independently moved up and down. Furthermore, the ribs 30a to 30d formed on the point clamps 30 and 40,
The shapes 0a to 40d are not limited to the shapes shown in FIG. 2, and any shape such as a lattice shape, a square shape, or the like can be used as long as it can partially clamp the sheet S at the boundary portion of each mold.

Furthermore, the point clamps 30 and 40
As the operation of the male and female dies 1 and 2, when the male and female dies 10 and 20 are released.
The point clamps 30 and 40 may be separated after the 0 and 20 are separated. In addition, the male and female layout may be a staggered layout in addition to the grid-like layout shown in FIG.
In addition to the continuous type, a cut sheet having a certain length may be used, and various design changes can be made without departing from the scope of the invention.

According to the method of the present invention, a high-impact polystyrene sheet having a thickness of 0.17 mm, which has been printed, is laminated, and an expanded polystyrene sheet having an overall thickness of 2.65 mm and an expansion ratio of 10 is used. When a cup-shaped container having a drawing ratio of 1: 0.4 to 1: 1.0, which is the ratio of the height of the side wall to the height of the side wall, is vacuum-formed, the thickness of each container is 0.
Individual containers having excellent strength of 2 to 4 mm, excellent reproducibility of fine printing, and excellent in-place printability were obtained. In addition, individual containers were obtained with uniform thickness and outer dimensions and without wrinkles or cracks.

A molded product having a drawing ratio of less than 1: 0.4, which is the ratio of the diameter of the upper surface opening and the height of the side wall, can be formed without using the point clamps 30, 40 of the present invention. A container having a good appearance can be obtained.

[0026]

As described above, according to the method for producing a container from the thermoplastic foamed resin sheet of the present invention, the amount of drawing in the deep drawing of a large number of pieces can be increased, so that each container can be It is possible to manufacture a product having excellent reproducibility of fine printing and in-place printability and having a sufficient thickness.

Further, since the sheet can be drawn in uniformly and stably at the time of molding, good molding can be realized in terms of uniform thickness and outer shape stabilization and dimensional stability, and a deep-drawing molded container is also good in quality. Can be manufactured.

[Brief description of drawings]

FIG. 1 is a side view showing the outline of an apparatus used in a method for producing a container from a thermoplastic foam resin sheet according to an embodiment of the present invention.

FIG. 2 is a bottom view of the female die side of FIG.

FIG. 3 is a partially enlarged sectional view of the female mold and the male mold of FIG.

FIG. 4 is a cross-sectional view showing a starting state in a molding process by the male and female molds of FIG.

5 is a cross-sectional view showing a lowered state of the female-side point clamp in the molding process by the male and female dies of FIG. 1. FIG.

FIG. 6 is a cross-sectional view showing a raised state of the male and male point clamps in the molding process by the male and female dies of FIG. 1;

FIG. 7 is a cross-sectional view showing a mold clamping state of the male and female dies in the molding process by the male and female dies of FIG.

FIG. 8 is a cross-sectional view showing a vacuum molding state in a molding process by the male and female molds of FIG.

9 is a cross-sectional view showing a lowered state of the male and male point clamps in the molding process by the male and female dies of FIG. 1. FIG.

FIG. 10 is a cross-sectional view showing a raised state of the female-side point clamp in the molding process by the male and female dies of FIG.

FIG. 11 is a cross-sectional view showing a mold release completed state in a molding process by the male and female molds of FIG.

FIG. 12 is a perspective view showing a molded product manufactured by the apparatus for use in FIG.

FIG. 13 is a bottom view of the female mold side used in the conventional method.

[Explanation of Codes] S Thermoplastic Foamed Resin Sheet S1 Original Fabric A Heating Means B Vacuum Forming Equipment C Molded Product 10 Female Mold 20 Male Mold 30 Point Clamp 30a Corner Rib 30b Side Rib 30c Crossover Rib 30d Misalignment Rib 32 female through hole 40 point clamp

Claims (1)

[Claims] 1. A method for continuously producing a large number of deep-drawing molding containers from a long thermoplastic foamed resin sheet in a plasticized state by heating with a molding die, wherein the sheet is provided on both sides. Is clamped to the feeding means and can be operated independently of the male and female dies, using the point clamps that pinch the sheet to a minimum, the boundaries between the female and male individual dies A method for producing a container from a thermoplastic resin foam sheet, which comprises clamping a sheet at a portion and then closing a mold to perform molding.