JPH0671768A - Decomposable buffer material and its manufacture - Google Patents

Abstract

PURPOSE:To make green decomposable resin cope with even highly foaming as a buffer material by a method wherein a die composing a narrowed opening is made of an open-cell material, and a swollen extruded product to be obtained by releasing suddenly from a heating pressurized state in a cylindrical container is obtained by forming into a shape according to a shape in a section of the die. CONSTITUTION:Green decomposable resin particles P which are made to contain water in a pretreatment process are supplied to a hopper 11. Temperature of the particles is increased roughly to a softening point to a melting point by shear in pushing feed and heating with a heater 14 while it is being push- supplied foreward in a cylinder 10 with a screw 13, and extruded in a fluid state from a throat part 12a. Since the green decomposable resin heated and pressurized by that time is suddenly exposed in atmospheric pressure, at that instant, the water content evaporates instantaneously. Then, through the resin is swollen as its sectional area is expanded by expansive force of water vapor in the die 12, since the die 12 is composed of an open-cell material, a continuous rod like swollen extruded product is obtained.

Description

Detailed Description of the Invention

[0001]

[Object of the Invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biodegradable resin which has recently been in the spotlight as being environmentally friendly and environmentally friendly, and more specifically to a foaming and shaping technique for them.

[0002]

BACKGROUND OF THE INVENTION Since synthetic resins are excellent in mass productivity, moldability, and durability, they have achieved technological development and accompanying increase in consumption at a remarkable rate in this century. However, since the amount of these synthetic resins that have been discarded has become enormous, many synthetic resin products have also been found in the garbage that drifts on the sea or rushes to the coastline. At the refuse incineration plant, various problems have come to be raised due to the waste of synthetic resin. That is, since the synthetic resin has a very strong intermolecular bonding force, it emits high heat during incineration and damages the furnace wall, and the combustion gas contains a large amount of harmful gas. In addition, even if it is exposed to the wild, it does not rust or decompose with light or ozone, and there is no choice but to wait for it to be abraded by mechanical energy such as wind and rain and waves.
In particular, in the case of highly foamed materials such as packing cushioning materials, heat insulating materials, packing trays, etc., this requires only a large volume, and separate collection is not cost-effective, so that it may occur on the sea or on the coastline. Was an embarrassing entity, as it was white in color.

Under such circumstances, the recycling movement has been carried out, and degradable resins have been put on the market, and the technological development of degradable resins has been remarkable recently.
Consumption is also expanding. However, degradable resin,
Particularly, the biodegradable resin is difficult to be highly foamed by a conventional chemical foaming agent, because of the relationship between the softening point or melting point and the foaming temperature of the foaming agent, and the higher the foaming, the more brittle the resin becomes. Nowadays, a high foaming and shaping technique of biodegradable resin is especially required.

[0004]

[Technical Items Attempted to Develop] Therefore, the present invention uses a biodegradable resin without a special chemical blowing agent mechanism.
It is an object of the present invention to provide a foaming and shaping technique capable of coping with high foaming as a cushioning material.

[0005]

[Constitution of the invention]

[Means for Achieving the Object] That is, in the method for producing a degradable cushioning material according to the first invention of the present application, substantially water and a biodegradable resin are put into a cylindrical container having a narrowed opening in the front. , While pushing the biodegradable resin to the front narrowing opening, the die forming the narrowing opening is a continuous porous material when it is heated to the softening point or melting point and extruded as a fluid from the narrowing opening to the outside of the cylindrical container. As a manufactured product, the expanded extrudate obtained by being rapidly released from the heated and pressurized state in the cylindrical container and expanded in the die is shaped into a shape corresponding to the internal shape of the cross section of the die. And

The method for producing a degradable cushioning material according to a second invention of the present application is that the water and the biodegradable resin are substantially put into a cylindrical container having a narrowed opening at the front to biodegrade. When the flexible resin is pushed into the anterior stenosis opening, it is heated up to its softening point or melting point and is pushed into the shaping die from the stenosis opening in the fluidized state. As a continuous porous product, a puffed product obtained by being rapidly released from the heated and pressurized state in the cylindrical container and expanded in the shaping mold can be shaped into an overall shape according to the shaping mold. It is characterized by

Further, in the method for producing a degradable cushioning material according to the third invention of the present application, the water and the biodegradable resin are substantially put into a cylindrical container having a narrowed opening in the front to biodegrade. When the flexible resin is pushed into the anterior stenosis opening, it is heated up to its softening point or melting point and is pushed into the shaping die from the stenosis opening in the fluidized state. A palm fiber shaped object is placed inside while being made of a continuous porous material, and a swelling product obtained by being rapidly released from the heated and pressurized state in the cylindrical container and expanded in the shaping mold is a palm fiber. It is characterized in that it is obtained by incorporating it into a shaped body and shaping it into an overall shape corresponding to the shaping die.

A degradable cushioning material according to a fourth aspect of the present invention is characterized in that a coconut fiber is used as a base material, and a biodegradable resin is foamed by being intertwined with this. So,
It is intended to achieve the above object.

[0009]

According to the present invention, the biodegradable resin is heated and sheared while being pushed into the narrowed opening, and is heated to its softening point or melting point. It exists in a state of being forcedly confined in a biodegradable resin that has been heated to a softening point or a melting point under pressure. Therefore, by exiting the constriction opening, the heating and pressurizing state is rapidly released in the die or the shaping mold, and the water trapped inside expands and expands at once. At that time, the outermost contour is restricted to a die or a shaping die made of a continuous porous material, and an expanded product shaped into a shape corresponding to the inner shape of the die cross section or the shape of the shaping die is obtained. At this time, if the palm fiber shaped body is previously arranged in the shaping die, the palm fiber shaped body is entangled and swelled to form a puffed product using this as a base material. In addition, the expanded product thus obtained has a high shape-retaining property due to the presence of coconut fiber.

[0010]

EXAMPLES The present invention will be described below with respect to its constituent elements, biodegradable resin, swelling, and coconut fiber, and then each example will be specifically described. Therefore, the biodegradable resin in the present invention means a resin material whose physical properties are deteriorated based on a biological action, and this includes a type in which the resin itself is completely decomposed and a disintegrating property which is blended with a resin which is difficult to decompose. There is a type given. The former type includes products produced by microorganisms, products using natural polymers, products produced from petroleum-based raw materials, and the latter type includes blends with starch and blends with aliphatic polyesters. Etc.
These biodegradation mechanisms include lipase, amylase,
There are various modes such as decomposition by enzymes such as cellulase and protease, decomposition by microorganisms such as in activated sludge, decomposition by soil in a natural environment such as forest and cultivated land. More specifically, polyhydroxybutyric acid and its derivatives, pullulan, cellulose-chitosan mixtures, esterification products of cellulose, amylose and wood flour, polyester-nylon copolymers, polyester copolymers, blends of starch and polyethylene. The body, polyvinyl alcohol,
Examples include polyethers, polyurethanes, polyamides and the like. These generally have low melting points and are accelerated in the presence of water.

On the other hand, puffing is known as a technique in the production of so-called snacks such as popcorn, and in the case of snacks, grains having an appropriate amount of water are used in a high-temperature and high-pressure container. When it is released to a low pressure suddenly after holding it until the product temperature rises sufficiently, the moisture in the grain tissue causes instantaneous evaporation,
It is a phenomenon in which the tissue expands due to the expanding pressure of water vapor at that time, and it is performed by various types of devices such as a batch type puff gun, a belt conveyor type, a fluidized bed type, and an extruder type. In the present invention, the puffing technique for these foods is applied as a foaming and shaping technique for a biodegradable resin.

[0012] The term "palm fiber" means fibers other than fibrous bark, petiole base fiber, mesocarp fiber, etc. in palm trees distributed from tropical to subtropical regions, banana trunks, pineapple leaves, abaca leaves, etc. Fruits, etc. shall be harvested but also contain relatively thick and hard plant fibers that were often discarded in the past. All palm trees are evergreen shrubs or trees, and they have a single trunk that does not divide branches and has a leaf crown at the tip, which has almost no trunk or is 30 meters high. There are some that have a smooth surface and some that are tightly wrapped in an old leaf sheath. In addition, there are some species such as tows that climb high on the tree with a vine as a vine, ones whose stems bulge like a cone, and some exceptional species that branch into two branches, such as the genus Hyphaene. The leaves are usually large, palm-like or winged, leathery, and the base of the petiole is a wide leaf sheath to hold the stem firmly. There are many fibers in the leaf sheath, and depending on the type, when old, the soft tissue rots, leaving only the fibers, resulting in so-called palm skin. The inflorescences are large, panicle-like inflorescences of apical or aerial, and diverge well. In the case of apical, the flowers die when the flowers bloom. If fertilized by wind or insects and the fruit is berries or drupes,
The endocarp is usually attached to the seed and the mesocarp has a thick fiber layer. Specifically, palm trees presenting the bark as fibrous include palm, genus, palm,
For those that provide fibers at the base of petiole, those that provide fibers of Chamaelops genus Chabotouju, peafowl peafowl, pearl beetle, date palm, date palm, sago palm, black clover, sugar palm, mesocarp, coconut coconut, nipa There are genus Nippa palm and so on.

These coconut fibers can be formed into an appropriate shape such as a sheet or a block by entwining the fibers with each other by rolling, laminating, needle punching, cutting or the like by hand. In addition, such a coconut fiber shaped body may be coated with an adhesive to strengthen the binding between the fibers, metal sprayed or ceramic sprayed, or further entangled with long metal fibers.

In this example, the biodegradable resin used was Mater-Bi "Matterby" (registered trademark) pellets sold by Nippon Synthetic Chemical Industry Co., Ltd.
This is a NO belonging to the Montedison Group in Italy
In connection with the development of VAMONT, it is considered as a thermoplastic biodegradable polymer in which derivative products from multiple agricultural products such as starch and denatured polyvinyl alcohol infiltrate into the partner molecule at the molecular level and are linked by hydrogen bond. It is what Further, it is said that biodegradation is promoted by absorbing water and swelling, and exhibits biodegradability equivalent to that of paper in an environment in which microorganisms survive.

Further, in this embodiment, a pretreatment step of positively containing water in the granules of the biodegradable resin was provided. Specifically, after soaking the biodegradable resin granules in a container filled with sufficient water for a certain period of time, take out the hydrous biodegradable resin granules and remove water droplets adhering to the surface. , And was subjected to the following steps. In addition to this, in this pretreatment step, it may be immersed in appropriately heated or boiled hot water for a certain time, or may be left for a long time in a controlled high humidity atmosphere. By providing such a pretreatment step, more uniform water than the equilibrium water content in the atmosphere can be included in the particles of the biodegradable resin, so that more stable and high foaming can be achieved. it can. Of course, even with a biodegradable resin having an equilibrium water content in the atmosphere, depending on the required expansion ratio or the degree of heating and pressurization, there is no need to intentionally perform this pretreatment step, and the biodegradable resin that is left in the air and contains the equilibrium water content is not necessary. The decomposable resin may be used as it is. Furthermore, since it suffices that water is finally contained under pressure in the biodegradable resin, the water itself is directly added together with the biodegradable resin to substantially supply the biodegradable resin and water. It may be done.

In FIG. 1, reference numeral 10 is a cylinder, a hopper 11 is provided above the starting end thereof, and a die 1 is provided at the end leading end thereof.
2 are provided, and the insides of these are communicated with each other, and the inside of the cylinder is formed as a tapered wall 10a that narrows toward the tip. The screw 1 is installed in the cylinder 10.
3 is provided in the vicinity of the tapered wall 10a, and a heater 14 for heating is arranged around the cylinder 10. The die 12 is communicated with the inside of the cylinder 10 through the throat portion 12a and is not made of a solid metal material before the throat portion 12a. It is made of a porous material having textured pores. As this porous material,
In addition to foamed metal, sintered materials such as metal or ceramics that are sintered and formed by adding fillers that can form voids, and those obtained by press-forming wire mesh, punching metal, etc., and stacking them , And various forms. Here, if the mesh-like pores are relatively large, there is an advantage that they can be rapidly exposed to low pressure during expansion, but the irregularities due to the pores appear strongly in the finish after expansion. Since the surface is rough and this also acts as extrusion resistance, it is desirable that the pores be minute within a range where the flow resistance of water vapor does not become extremely high, and a preferable example is foamed ceramics. Further, it is advantageous that the length thereof is appropriately long for shaping and solidifying the shape.

In such an extrusion-type expansion apparatus A, if the biodegradable resin granules P hydrated in the pretreatment step are supplied to the hopper 11, the biodegradable resin granules charged in the cylinder 10 are supplied. P is the cylinder 10 by the screw 13.
Since the inside of the cylinder 10 is narrowed as it moves forward while being pushed inside, the shearing force at the time of pushing and the heating from the inner wall of the cylinder 10 by the heater 14 causes a softening point or a melting point to be reached. The temperature is raised to at least, and at least immediately before the throat portion 12a of the die 12, it becomes a fluid state and is extruded as a fluid state from the throat portion 12a. At this time, granules of biodegradable resin are successively supplied from the rear into the cylinder 10, and the throat portion 12a of the die 12 and the tapered wall 10 are extruded forward.
Since it is limited by a, the water contained in the granules of the biodegradable resin under high temperature pressurization is forcibly confined in the biodegradable resin without being evaporated from the granules of the biodegradable resin. Will be sent. Therefore, at the moment when the biodegradable resin is extruded into the die 12 through the throat portion 12a in a fluid state, the biodegradable resin which has been heated and pressurized until now is rapidly exposed to the atmospheric pressure. Because of this, the water that is trapped in it will evaporate instantly. At this time, the biodegradable resin is in a fluid state and is expanded as the cross-sectional area is expanded by the force of expansion of the steam in the die 12, but in the present invention, the die 12 is made of a continuous porous material. The expansion at that time regulates the inner shape of the cross section of the die 12 as the outermost contour, and a continuous rod-shaped expanded extrudate shaped according to this is obtained. For this reason, the die 12 needs to have a cross-sectional area smaller than the extent to which the biodegradable resin extruded from the throat portion 12a freely expands. In the present embodiment, the die 12 and its throat portion 12a have a cylindrical shape,
After that, a rotary cutter (not shown) is operated at the tip of the die 12 at a timing to cut it into a certain length to obtain a large number of expanded extrudates S ₁ having an appropriate length.

Since the degree of heat and pressure applied to the granules of the biodegradable resin and the degree of water content as a pretreatment step have a great influence on the degree of expansion in the die 12 and the solidification of the shape immediately after that, the biodegradable resin is It is necessary to set process conditions such as the rotation speed of the screw 13 and the degree of energization of the heater 14 according to the physical properties and grade. If these conditions are not met, the degree of expansion will be insufficient, or conversely the degree of expansion Is too large and bursts, or it expands once and then contracts. The front area of the die 12 may be slightly enlarged or reduced so that the portion can be heated by a heater, and the surface of the obtained extruded extrudate is fused to form a smooth skin layer.

The expanded extrudate S ₁ of the biodegradable resin thus obtained can be used, for example, as a cushioning material for a package in a cardboard box for packaging. Even if it is illegally dumped, it will biodegrade, so even if it floats on the sea or hits the coastline, it will be decomposed after a while, and even if it is left on the ground, it will wind and rain and underground. Since it absorbs the moisture of the product and decomposes, there is no need to dispose of it at a refuse incineration plant. Moreover, it is obtained as a relatively high foaming product, and is obtained without any special chemical blowing agent mechanism. Of course, the die 12 is not limited to the cylindrical shape, but symmetrical or asymmetrical different shapes can be appropriately used.
For example, an angled expanded extrudate S ₂ as shown in FIG.
Can be used as it is as a corner support material.

For example, the expanded extrudate S ₁ obtained by shaping into a cylindrical shape is arranged, pressed and heated in a rectangular flat mold 15 with an edge as shown in FIG. It is also possible to shape it into a large shape that is wholly integrated. At this time, if the degree of heating to the mold 15 exceeds the melting point of the biodegradable resin, the meaning obtained as the expanded extrudate S ₁ before that is lost, so that the biodegradable resin having a low melting point is used. It may be carried out by adding the expanded extrudate separately, or by adding powder of a decomposable resin having a low melting point, a thermoplastic resin, and a component having an adhesive function such as glue. As the adhesive component, in addition to this, starch paste, furi, gum arabic, glue, casein, linseed oil, starch derivatives such as starch acetate / carboxymethyl starch, fibrin derivatives such as methyl cellulose / ethyl cellulose, sodium alginate, locust bean gum, Vinyl synthetic glue such as polyvinyl alcohol, vinyl copolymer synthetic glue such as vinyl acetate acrylic acid copolymer, acrylic synthetic glue such as sodium polyacrylate, styrene synthetic glue such as styrene-maleic acid copolymer In addition to natural adhesives, semi-synthetic adhesives, and synthetic adhesives, adhesives, as well as solutions in which various resins are appropriately dissolved in a solvent, thermoplastic resins, decomposable resin powders having a low melting point, and the like can be used. Further, it may be made to adhere and adhere with an adhesive elastomer such as silicone gel or urethane gel. If a natural or biodegradable adhesive component is used, a completely pollution-free degradable cushioning material can be obtained. Further, of course, one of heating and pressurization may be applied, and the shape is not limited to the rectangular flat mold shown in the figure, and may be formed into a unique shape by a modified mold.

In addition to the above examples, the obtained extruded extrudate is once dipped in a component such as an adhesive component capable of forming a solidified film to such an extent as not to be impregnated inside, and then dried to form a skin layer on the surface. It may be formed, or a skin layer may be formed in the same manner with respect to the integrated body, or further, a film pack may be formed along the outer shape thereof, and thus the inside is hermetically sealed. Then, a buffer effect due to the air layer trapped inside can be expected. If a film formed from a biodegradable resin is used for this film, the degradability will not be impaired. Separately from this, as a post-treatment step, a water-repellent or water-resistant coating material such as silicone or a colored coating material is applied, and an insect repellent or an insecticide component or the like is applied in the coating material or in any of the above steps. May be added. Of course, the pre-treatment process and these post-treatment processes are not always necessary and can be appropriately added.

Next, one embodiment of the second and third inventions according to the present application will be described in which the so-called in-line screw type injection molding machine B is used to expand and shape the biodegradable resin. To do. That is, FIG. 4 shows a main part thereof, and 20 is a cylinder, a hopper 21 is provided above the starting end of the cylinder, and a nozzle 22 is provided at the tip of the cylinder. A heater 24 for heating is arranged in the. A screw 23 is provided in the cylinder 20 close to the inner wall 20a. The rear end of the screw 23 is extended to the outside of the cylinder 20, and the hydraulic motor 25
And a piston 26 at the rear end. The piston 26 is slidably arranged in the injection cylinder 27, and the piston 26, the hydraulic motor 25, and the screw 23 integrally move back and forth by hydraulic pressure, and the screw 23 is rotatable by the hydraulic motor 25.

Numeral 28 is a fixed side mold, and in the embodiment, a cavity 28a having a substantially triangular pyramid shape is formed. Also,
Reference numeral 29 denotes a movable-side mold, which is a small core 29 having a substantially triangular pyramid shape.
a is formed, and when both molds are clamped, a space similar to that shown in FIG. 5 is formed inside. This mold is fixed together with other accessory parts on the fixed side and the movable side of a die plate, which is a conventionally known mold clamping mechanism (not shown), and flows in the cylinder 20 via the fixed side of the die plate. The biodegradable resin is injected from the nozzle 22 into the mold cavity 28a. In this embodiment, the movable mold 29 is used.
Is not made of a solid metal material, but is made of the same porous material as in the above embodiment.

Therefore, as shown in FIG. 4A, by supplying the biodegradable resin granules P to the hopper 21 in the mold clamped state, the biodegradable resin granules put into the cylinder 20 are supplied. P is a shearing force at the time of pushing and the heater 2 while being pushed forward in the cylinder 20 by the screw 23.
By heating from the inner wall of the cylinder 20 by means of No. 4, the temperature is raised to about the softening point or the melting point and accumulated in a fluid state at the tip of the screw 23. At this time, the inside of the granules of the biodegradable resin was pressurized under high temperature, and the water contained in the granules of the biodegradable resin did not evaporate from the granules of the biodegradable resin, and it was forcibly confined in the biodegradable resin. Has become. Then, as shown in FIG. 4B, the rotation of the screw 23 is stopped,
The piston 26 is operated by the injection cylinder 27 and the screw 23 is moved forward to move the fluidized material to the nozzle 22.
From the mold into the cavity 28a of the mold at once.

The biodegradable resin is in the form of fluid in the cavity 28.
At the moment when it is pushed into a, it will be suddenly exposed to atmospheric pressure from the previously heated and pressurized state, so the water trapped in it will momentarily evaporate and the water vapor will expand. Although its cross-sectional area expands with the force of, the outermost shell is restricted to the shape of the cavity 28a while appropriately filling the inside of the mold by pushing in an appropriate amount at once, as shown in FIG. 5, for example. A swelling product in which the whole is shaped into one is obtained. At this time, at least a part of the mold is made of a continuous porous material, so that the gas pressure generated during expansion can be appropriately released to the outside of the mold, and the expanded solid is cooled and solidified. Before it is crushed by its own gas pressure, it cools and solidifies in the expanded and expanded shape. Therefore, it is important that at least a part of the mold is made of continuous porous material in order to control the timing of expansion and expansion and cooling and solidification, and to what extent is made continuous porous material. No matter how many gates are used, it is preferable to design appropriately according to the size to be shaped and the overall shape. On the other hand, the biodegradable resin which has become fluid again while retreating while rotating the screw 23 begins to accumulate at the tip of the screw 23 and prepares for the next injection. Within the mold cavity 28a during this time, since also complete cooling and solidification after swelling, remove the puffed product S ₃ and the mold is opened, the following operations again clamping.

An embodiment of the third invention relating to the present application is achieved by arranging a palm fiber shaped object in the mold cavity 28a prior to injection in the embodiment described with reference to FIG. To be done. That is, palm fibers are manually packed in a mold by hand, laminated, needle-punched sheet-shaped ones are combined in a mold, corners of a cube-shaped one are cut off, and a cube-shaped one is pressed. The obtained coconut fiber shaped body can be placed in a mold by, for example, compressing it into a shape similar to the cavity. By placing the coconut fiber shaped object in the mold, when the biodegradable resin swells in the mold, it becomes entangled with the coconut fiber and a swelling product entangled in the coconut fiber shaped object can be obtained. . That is, as shown in FIG. 5, palm fiber 3
The base material 0 is used as the base material, and a swelling product S ₄ is obtained which is formed by intricately incorporating the base material into a biodegradable resin. Therefore, since the expanded product S ₄ thus obtained is in a fiber-reinforced state with palm fiber, the brittleness is reinforced even if the biodegradable resin is highly foamed, which is high. It has a shape-restoring property and is more suitable as a cushioning material.
In addition, even if this is discarded, since palm fiber is a natural product, it can be biodegraded and incinerated, and it does not pollute the environment. If the palm fiber shaped body is sprayed with metal or the long metal fibers are intertwined with each other, conductivity is imparted to the expanded product, and electrostatic removal, electromagnetic wave shielding effect, etc. can be expected. Since the metal is oxidized, it has little adverse effect on the environment.

The decomposable cushioning materials as the expanded products S ₃ and S ₄ thus obtained can be used as they are as the corner supporting materials at the four corners of the packaging cardboard box. Further, it may be bonded to another degradable cushioning material in the same manner as in the above example, or a water-resistant solidified film or skin layer may be formed,
A film may be packed along the outer shape, a water-repellent or water-resistant paint such as a silicone-based paint or a colored paint may be applied, or an insect repellent or an insecticide component may be applied.

As described above, according to the present invention, after being shaped by the continuous porous die, the secondary molding process and the like are performed, and the continuous porous shaping mold is used to form the whole shape. Can be obtained at once in the form of a cushioning material having various shapes, and can be used in the same manner as in the case where a conventional foamed material such as Styrofoam is used. Further, rather than being used as a cushioning material, it is naturally possible to deal with usage such as a heat insulating material. In this sense, the degradable cushioning material referred to in the present application is intended only for strict cushioning. In addition to the above-mentioned applications, it includes a wide range of applications and products applicable as highly foamed products. Also, in the above examples, the biodegradable resin was used as Mater-Bi "Matterby" (registered trademark).
However, the present invention is not limited to these, and other biodegradable resins, and biodegradable resins of various sizes and shapes can be applied. . Further, of course, it is not limited to the illustrated apparatus, for example, an in-line screw type injection molding machine.

[0029]

As described above, according to the present invention, the biodegradable resin can cope with high foaming without depending on a special chemical foaming agent mechanism, and can be foamed and shaped into an appropriate shape. In terms of strength, it can be provided as a substitute for conventional foams, and can now contribute to the reduction of dust pollution, which is an important issue.

[Brief description of drawings]

FIG. 1 is a schematic vertical cross-sectional view of an extrusion-type expansion device which is an example of a device for carrying out an embodiment of the method for producing a degradable cushioning material of the present invention.

FIG. 2 is a perspective view of a swollen extrudate having an angled cross section.

FIG. 3 is a perspective view showing a state in which a large number of expanded extrudates are aligned in a molding die to integrate the whole.

FIG. 4 is a schematic vertical cross-sectional view of an in-line screw injection molding machine which is an example of an apparatus for carrying out another embodiment of the method for producing a degradable cushioning material of the present invention.

FIG. 5 is a perspective view showing a case where a decomposable cushioning material formed by coconut fiber as a base material and a biodegradable resin foamed intricately as a corner support member is obtained.

[Explanation of Codes] A Extrusion type expansion device B In-line screw type injection molding machine P Granules of biodegradable resin hydrated S ₁ Expansion extruded product S ₂ Expansion extruded product S ₃ Expanded product S ₄ Expanded product 10 Cylinder 10 a Taper Wall 11 Hopper 12 Die 12a Throat part 13 Screw 14 Heater 15 Edged rectangular flat mold 20 Cylinder 20a Cylinder inner wall 21 Hopper 22 Nozzle 23 Screw 24 Heater 25 Hydraulic motor 26 Piston 27 Injection cylinder 28 Fixed side mold 28a Substantial triangular pyramid -Shaped cavity 29 Movable side mold 29a Core of substantially triangular pyramid 30 Palm fiber

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Claims (4)

[Claims] 1. A substantially cylindrical container having a constriction opening at the front, into which water and a biodegradable resin are put, and while the biodegradable resin is pushed to the front constriction opening, its softening point or melting point. When extruding from the constriction opening to the outside of the cylindrical container by raising the temperature to the outside of the cylindrical container, the die forming the constriction opening is made of continuous porous material, and is rapidly released from the heating and pressurizing state in the cylindrical container. A method for producing a degradable cushioning material, which comprises obtaining an expanded extruded product obtained by expanding the product in a shape according to the internal shape of the cross section of the die. 2. Water and biodegradable resin are substantially put into a cylindrical container having a front narrowed opening, and while the biodegradable resin is pushed to the front narrowed opening, its softening point or melting point is reached. When pressing into the shaping mold of the other side from the constriction opening by raising the temperature to a fluid state, the shaping mold is made of at least a part made of continuous porous material, and is rapidly heated from the heated and pressurized state in the cylindrical container. A method for producing a degradable cushioning material, which comprises releasing an expanded product obtained by swelling in the shaping mold to give an overall shape corresponding to the shaping mold. 3. A water-degradable resin and a water-degradable resin are substantially put into a cylindrical container having a narrowed opening at the front, and while the biodegradable resin is pushed to the front narrowed opening, its softening point or melting point is reached. When pressing it into the shaping mold of the other side from the constriction opening as a fluid state by raising the temperature to, the shaping mold is made at least a part of it made of continuous porous material and the palm fiber shaped body is placed inside. , A swelling product obtained by being rapidly released from the heating and pressurizing state in the cylindrical container and swelling in the shaping mold is incorporated into a coconut fiber shaped body and shaped into an overall shape corresponding to the shaping mold. A method for producing a degradable cushioning material, which is obtained by shaping. 4. A degradable cushioning material comprising coconut fiber as a base material, and a biodegradable resin foamed in the base material.