JPH11170379A - Molding method of biodegradable material and molding machine therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding method of a biodegradable material which can mold a molding having the strength and shape stability needed as a buffer material for packaging from the biodegradable material of which the main raw material is the starch of corn or the like. SOLUTION: This molding method of a biodegradable material comprises a material-filling process wherein a biodegradable material 42 prepared by applying a hot-melt binder by coating on the surfaces of foamed beads of which the main raw material is starch is filled in an in-mold space formed by a fixed half 3 and a movable half 28, a material compressing process wherein the biodegradable material in the in-mold space is compressed thereafter in such a degree that air permeability is maintained, by narrowing further a gap between the fixed half 3 and the movable half 28, a material heating process wherein the binder is melted by heating the biodegradable material 42 by blowing hot air into the in-mold space, a material cooling process wherein the biodegradable material 42 is caked thereafter by blowing cool air into the in-mold space and an eject process wherein molding is taken out of the in-mold space by withdrawing the movable half.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biodegradable material molding method and a molding machine for molding a molded article of a desired form from a biodegradable material mainly made of starch such as corn. It is.

[0002]

2. Description of the Related Art Styrofoam, which has been widely used as a cushioning material for packaging, does not decompose naturally when it is turned into waste, which may lead to environmental destruction, and incineration produces harmful gases. In addition, there is a problem that the furnace is easily damaged due to large calories burned.

[0003] Therefore, it has been conventionally used to pack particles obtained by expanding grains such as corn into small bags or the like and use them as a cushioning material. When buried in soil, such biodegradable materials are broken down into carbon dioxide and water by microorganisms, and there is no danger of harmful gas emissions or damage to the furnace when incinerated. It is useful.

[0004]

However, such a biodegradable material does not expand significantly in a molding machine mold by heating as in the conventional styrofoam molding, and the materials themselves are bonded to each other. Since the force for consolidation is weak, it is not easy to mold as with styrofoam. For this reason, conventionally, with this biodegradable material, it has been impossible to obtain a molded product having strength and shape stability required as a cushioning material for packaging.

[0005] The present invention solves the above-mentioned problems and provides a biodegradable material capable of forming a molded article having strength and shape stability required as a cushioning material for packaging from a biodegradable material mainly containing starch such as corn. An object of the present invention is to provide a method and a molding machine for forming a conductive material.

[0006]

In order to achieve the object, a method for molding a biodegradable material according to the present invention comprises fixing a biodegradable material obtained by coating a surface of foamed beads mainly composed of starch with a heat-fusible binder. A material filling step for filling the cavity in the mold formed by the mold and the movable mold, and thereafter, the gap between the fixed mold and the movable mold is further narrowed to maintain the gas permeability of the biodegradable material in the cavity in the mold. A material compression step of compressing the material to a degree that the material can be compressed, a material heating step of blowing hot air into the mold cavity to heat the biodegradable material and melting the binder, and then blowing a cool air into the mold cavity to form the raw material. The method is characterized by comprising a material cooling step of consolidating the decomposable material and an ejecting step of retracting the movable mold and removing the molded product from the cavity in the mold.

[0007] The biodegradable material molding machine according to the present invention comprises:
A fixed mold is fixed on the front surface of a plate-shaped mold stand erected on a frame, an eject pin is provided to penetrate the fixed mold, and the eject pin is fixed to a mounting frame fixed to a rear end of the eject pin. A mold opening cylinder is provided for moving the mold guide rod forward and backward, and a mold clamping cylinder is further provided on the mounting frame to move a mold guide rod inserted through the mold base so as to be able to move forward and backward. The movable mold opposite to the fixed mold is fixed to the mold, and the eject pin is retracted by operating the mold opening cylinder, and at the same time, the mold cavity is formed by the fixed mold and the movable mold, and the mold clamping cylinder is operated. In this case, the distance between the fixed mold and the movable mold is further reduced, so that the biodegradable material in the cavity in the mold can be compressed. Further, the present invention provides the biodegradable material molding machine, wherein the heating means for forming a fixed mold and a movable mold with a gas permeable plate having a large number of small air holes formed therein, and blowing hot air or cold air through the air holes into a cavity in the mold. And cooling means.

[0008]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a side view of the biodegradable material molding machine, FIG. 2 is a plan view of a main part thereof, and FIG. 3 is a sectional view taken along line AA. In the figure, reference numeral 1 denotes a board-shaped mold stand erected on a frame 2, and 3 denotes a fixed mold fixed to the front of the mold stand 1. As shown in the vertical sectional views of FIGS. 4 to 6, the fixed die 3 is in the form of a square cell, and has a gas permeable plate 4 having a plurality of small air holes formed on the bottom surface thereof. ing. 5
Is an eject pin penetrating the mold base 1 and the fixed mold 3,
A projecting member 6 is provided at the tip of the eject pin 5. Reference numeral 7 denotes a concave portion formed in the gas permeable plate 4 for accommodating the projecting member 6. Reference numeral 8 denotes an air supply plenum chamber provided on the back surface of the air permeable plate 4, and the chamber communicates with a hot air supply port 9 and a cool air supply port 10. Numeral 11 denotes a sheet heater which faces the air permeable plate 4 and is provided for keeping the fixed mold 3 warm. Numeral 12 denotes a material inlet provided on the side wall of the fixed mold 3.

Reference numeral 15 denotes a nut 1 at the rear end of the eject pin 5.
A mold opening cylinder (air cylinder) 17 is fixedly mounted on the front side of the mounting frame 15 with the mounting frame fixed by 6, and the tip of an operating shaft 18 of the cylinder 17 is fixed to the rear surface of the mold base 1. . Reference numeral 19 denotes a mold clamping cylinder (air cylinder) fixed coaxially to the mounting frame 15 so as to be back-to-back with the mold opening cylinder 17.
The tip is fixed to the connecting member 21.

Reference numeral 25 denotes a mold guide rod which is inserted into the four corners of the mold base 1 so as to be able to move forward and backward, respectively. A holder 26 is fixed to the tip of the mold guide rod 25 by a nut 27, and the holder 26 is fixed to the holder 26 The movable mold 28 facing the mold 3 is fixed. The rear end of the mold guide rod 25 is fixed to the connecting member 21 by a nut 29.

The movable mold 28 includes a gas permeable plate 30 having a large number of small air holes, and a plenum chamber 31 for intake is formed on the back of the gas permeable plate 30, and the chamber communicates with an air inlet 32. ing. Reference numeral 33 denotes a planar heater which faces the air permeable plate 30 and is provided for keeping the movable mold 28 warm.

A hot air generator 35 generates hot air at about 270 ° C. and sends the hot air to the air supply plenum chamber 8 through the tube 36 and the hot air supply port 9. Reference numeral 37 denotes a cold air tube for supplying compressed air from an air pressure source (not shown) to the air supply plenum chamber 8 through the cold air supply port 10. An intake fan 38 communicates with the intake port 31 via a flexible tube 39.

Reference numeral 40 denotes a material tank, and 41 denotes a material for sucking the biodegradable material 42 in the material tank, and
This is an ejector pump that feeds the ejector. This biodegradable material 4
No. 2 is formed by coating polycaprolactone as a binder on the surface of porous foam beads (water foam) composed of 67% corn starch, 30% biodegradable resin polyvinyl alcohol, and 3% calcium carbonate.

Next, a description will be given of a molding method according to the present invention, in which a molded article for packaging buffer of a desired form is molded from the biodegradable material 42 using the molding machine. The planar heaters 11 and 33 always keep the fixed mold 3 and the movable mold 28 at about 60 to 70 ° C. In the material filling step, as shown in FIG. 4, the mold opening cylinder 17 is extended and the mold clamping cylinder 19 is contracted, so that the eject pin 5 is retracted and at the same time the movable mold 28 is fixed. 3 and the ejector pump 41 is inserted into the cavity formed by the mold.
Is operated to fill the biodegradable material 42.

In the material compression step, as shown in FIG. 5, the mold guide rod 25 is pulled by extending the mold clamping cylinder 19 while keeping the mold opening cylinder 17 in the extended state. Further, the biodegradable material that has entered the fixed mold 3 and filled in the mold cavity is compressed to such an extent that the gas permeability 42 is maintained.

In the material heating step, as shown in FIG. 5, the hot air from the hot air generator 35 is supplied from the chamber 8 to the air permeable plate 4.
While the air is blown into the mold cavity, the suction fan 38 is operated to depressurize the inside of the chamber 31, and the air in the mold cavity is sucked through the gas permeable plate 30 to circulate hot air through the mold cavity to allow the biodegradable material to flow. 42 is heated to thermally expand the expanded beads and to melt the polycaprolactone as a binder.

In the material cooling step, instead of blowing in hot air from the hot air generator 35, cold air is blown into the chamber 8 from the tube 37, and the cold air is blown into the cavity in the mold through the permeable plate 4 to be cooled in the cavity in the mold. The biodegradable material 42 is cooled by flowing cold air, and the biodegradable material 42 is solidified by coagulating polycaprolactone.

The ejecting step of taking out the molded article 43 thus formed from the cavity in the mold is as shown in FIG.
The movable mold 28 is separated from the fixed mold 3 by contracting the mold opening cylinder 17 and the mold clamping cylinder 19, and the molded product 43 is pushed out by pushing the eject pin 5 to project the projecting member 6.

[0019] In some cases, the swelling property and adhesiveness of the biodegradable material 42 can be improved by adding hot steam to the hot air and humidifying it. Also, the material tank 40
By pressing the biodegradable material 42 into the mold cavity by a pressure pump (not shown), the mold cavity can be filled with the material in a compressed state.

[0020]

As described above, in the method for molding a biodegradable material according to the present invention, the air permeability is maintained by further reducing the distance between the fixed mold and the movable mold by filling the biodegradable material filled in the mold cavity. To a certain degree and then blow hot air into the mold cavity to melt the binder and then blow cool air to consolidate the biodegradable material. Can be solidified by melting, and a molded article having strength and shape stability required as a cushioning material for packaging can be formed.

Further, in the biodegradable material molding machine of the present invention, the interval between the fixed mold and the movable mold can be set to two stages, that is, the material filling and the material compression, by operating the mold opening cylinder and the mold clamping cylinder. With this configuration, the biodegradable material filled in the cavity in the mold can be compressed with a simple structure to such an extent that air permeability is maintained, which is suitable for implementing the above-mentioned molding method.

[Brief description of the drawings]

FIG. 1 is a side view of a biodegradable material molding machine according to the present invention.

FIG. 2 is a plan view of a main part of the biodegradable material molding machine of FIG.

FIG. 3 is a cross-sectional view of the biodegradable material forming machine of FIG. 1 taken along line AA.

FIG. 4 is a longitudinal sectional view of a main part of a biodegradable material molding machine according to the present invention during a material filling step.

5 is a longitudinal sectional view of a main part of the biodegradable material molding machine of FIG. 4 during a material compression stroke.

6 is a longitudinal sectional view of a main part of the biodegradable material molding machine of FIG. 4 at the time of ejection.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold stand 2 Frame 3 Fixed type 4 Air-permeable plate 5 Eject pin 6 Projection member 8 Plenum chamber for air supply 9 Hot air supply port 10 Cold air supply port 12 Material input port 15 Mounting frame 17 Mold opening cylinder 19 Mold clamping Cylinder 21 Connecting member 25 Guide rod 26 Holder 28 Movable 30 Breathable plate 31 Plenum chamber for intake 32 Inlet 35 Hot air generator 37 Tube for cold air 38 Intake fan 40 Material tank 42 Biodegradable material 43 Molded product

Claims (3)

[Claims] 1. A material filling step in which a biodegradable material obtained by coating a surface of a foamed bead mainly made of starch with a hot-melt binder is filled in a mold cavity formed by a fixed mold and a movable mold. A material compression step of compressing the biodegradable material in the mold cavity to an extent that air permeability is maintained by further reducing the distance between the fixed mold and the movable mold,
A material heating step of blowing hot air into the mold cavity to heat the biodegradable material and melt the binder; and a material cooling step of subsequently blowing cool air into the mold cavity to solidify the biodegradable material. An ejecting step of retracting the movable mold and removing the molded product from the cavity in the mold. 2. A fixed die is fixedly mounted on a front surface of a plate-shaped mold stand erected on a frame, an eject pin is provided to penetrate the fixed die, and a fixed die is fixed to a rear end of the eject pin. A mold opening cylinder for moving the eject pin forward and backward is provided on the frame, and a mold clamping cylinder is further provided on the mounting frame to advance and retreat a mold guide rod inserted through the mold base so as to be able to move forward and backward. A movable mold opposed to the fixed mold is fixed to the tip of the mold guide rod, and the eject pin is retracted by operating the mold opening cylinder, and at the same time, the mold cavity is formed by the fixed mold and the movable mold. A biodegradable material molding machine characterized in that a biodegradable material in an inner space of the mold can be compressed by further narrowing an interval between the fixed mold and the movable mold by operating a tightening cylinder. . 3. A fixed type and a movable type are formed by a gas permeable plate having a large number of small air holes, and heating means and cooling means are provided for blowing hot or cold air through the air holes into a cavity in the mold. Item 6. A biodegradable material molding machine according to Item 2.