JPH083357A - Biodegradable resin foamed article, its manufacture and apparatus for manufacturing the article - Google Patents

Abstract

PURPOSE:To obtain the subject resin foamed article without removing remaining water by rapidly releasing pressure from a liquid acetate containing water trapped in it under pressure and heat or from a pressurized liquid biodegradable resin containing the acetate to carry out foaming by means of gasification expansion force of the released water. CONSTITUTION:A water-containing acetate or a biodegradable resin raw material 10 for producing a foamed article containing the water-containing acetate is charged from the hopper 11 into a cylinder 1 provided with a narrowed opening 1a at the front side. The charged material is delivered toward the narrowed opening 1a by a screw 2. During the delivery, the resin is heated to make it fluid. The pressurized liquid biodegradable resin is pushed out from the cylinder 1 into a forming space R in an air-permeable mold A placed in front of the cylinder 1. Since the pressure on the water trapping it in the fluidized resin in a heated pressurized atmosphere in the cylinder is rapidly removed, the resin is foamed by means of the gasification expansion force of the released water. Accordingly, the resin is formed into the shape of the mold A and the objective biodegradable resin foamed article is obtained without performing a treatment such as removing the remaining water and drying.

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 been in the limelight in place of a synthetic resin, and in particular, an acetate or a resin containing the same is applied as the biodegradable resin. The present invention relates to a biodegradable resin foam, a method for producing the same, and a production apparatus for the same, in which a decomposable resin is foamed to expand its use.

[0002]

BACKGROUND OF THE INVENTION Ordinary synthetic resins are widely used in various fields because they are excellent in mass productivity, moldability, and durability. Among them, synthetic resin foams are lightweight and have a high cushioning property. Since then, it has rapidly expanded its consumption and has been used in various applications such as protective cases for fragile items such as glassware, cushioning materials for packing transported items, food and drink containers, and heat insulating materials and soundproofing materials. . On the other hand, along with this, the amount of synthetic resin products to be discarded becomes enormous, which causes various problems.

That is, when a synthetic resin is incinerated, a large amount of harmful gas is generated to pollute the atmosphere, and when it is discarded as it is without being incinerated, it is not decomposed by oxidation or light or ozone, and thus has a shape as it is for many years. Maintain and pollute the environment.
In addition, since the synthetic resin has a very strong intermolecular bonding force, when it is incinerated, it generates high heat and damages the furnace wall of the incinerator, which shortens the service life of the incinerator.

For these reasons, biodegradable resins have recently attracted attention and have been actively developed. Since this biodegradable resin is decomposed by microorganisms in the soil or water, it is extremely effective as a waste countermeasure, and in particular, the development of biodegradable resins containing starch-based polymers has been developed. It is being advanced.

Regarding the processing technology of such biodegradable resin, the processing technology as a film material is currently being put to practical use, but if foaming can also be realized, its application will be greatly expanded, and the biodegradable resin The advantage can be utilized more. On the other hand, as a technique for foaming a synthetic resin, for example, styrene beads are put into a molding die, steam is added and then depressurized to obtain a group of expanded beads, and an extruder such as styrene resin A method is known in which a resin is added together with a foaming agent such as a solvent, and the resin is foamed by a pressure-reducing action when the resin is extruded.

However, the biodegradable resin is caused by the relationship between its softening point or melting point and the foaming temperature of the foaming agent.
It is difficult to achieve high foaming by the conventional chemical foaming technology used for ordinary synthetic resins. Therefore, there have been various problems as described below regarding the high foaming of the biodegradable resin and the molding technique.

First, as a first problem, for example, when an injection molding machine is used to produce a foam in the same manner as an ordinary synthetic resin, a biodegradable resin which is heated and pressurized into a fluid state in a cylinder is produced. The water in the biodegradable resin vaporizes and expands when it is extruded from the nozzle of the cylinder and decompressed, but the vaporized and expanded water then cools down and drifts in a steam state, or on the outer portion of the molding die or molded body. If you touch it, it will condense and become water drops. On the other hand, a biodegradable resin containing a starch-based polymer has a high hygroscopic property and easily softens and swells, and much less the film of each foamed cell in the outer peripheral portion of the molded body, so immediately when water drops touch it. Absorbs water and softens. As a result, each foam cell is crushed and the relevant part is shrunk, and the foam cell is crushed by reattachment of water evaporated from the biodegradable resin at the time of foaming, and as a result, the shape is deformed.
When this is dried and solidified, there is a problem in that the desired cushioning performance cannot be obtained because the foamed cells become solid without substantial foaming. Further, even when a foam is manufactured using a biodegradable resin having a small hygroscopic property that absorbs almost no water, it contains the biodegradable resin having a large hygroscopic property or an additive having a large hygroscopic property. In such a case, the above-mentioned problems occur, and even if such problems do not occur, it is necessary to separately remove the water adhering to the molded body and dry it.

The second problem is that the biodegradable resin starts foaming as soon as it is released from the pressurized state.
Since the biodegradable resin has a large viscosity when heated and is in a fluid state, it is difficult for the biodegradable resin to enter the deep part of the molding die, so part of the biodegradable resin is extruded from the cylinder and molded. It foams before it reaches the inner surface of the mold, and as a result, at the corners and complicated places of the molding mold, the part that should have reached the depth and should be foamed accumulates in the middle and accumulates in front of it. Due to this, a void is formed in the inner part, and the biodegradable resin that is subsequently extruded in this state presses the front foamed portion from the back surface, whereby the portion is crushed. Thus, if the portion is crushed from the back even after foaming once, there is a problem that a foam having a desired shape cannot be obtained and a product having sufficient cushioning performance cannot be obtained. It was

As a third problem, when the biodegradable resin that is heated and pressurized to be in a fluid state is released, the water in the biodegradable resin vaporizes and expands to foam. Since the heat of vaporization is removed, the temperature of the foam falls to about 100 ° C. When the temperature decreases in this way, the foam contracts slightly and solidifies in that state. In addition, since the entire foam is integrated and molded, cavities and voids are generated in the foam after solidification, and discontinuous boundaries are formed, which makes it unsuitable as a cushioning material. There was also a problem.

Further, as a fourth problem, a decompression pump or the like is used to change the heating and pressurizing atmosphere in which the biodegradable resin is present to a depressurized atmosphere. Takes a considerable amount of time, which slows down the depressurizing action, and when the water is not sufficiently discharged, it is necessary to separately remove and dry the water adhering to the mold and the molded body. In order to prevent such moisture from adhering, it is conceivable to use a large decompression pump or the like to shorten the time required for decompression exhaustion, but in this case, the manufacturing cost of the device will increase. Further, when injection is performed from a nozzle of a cylinder in an injection molding machine into a molding die arranged in a closed atmosphere, injection resistance increases. Therefore, a larger injection molding machine is required. Manufacturing cost will be increased. In particular, in order to obtain a foam with high shape accuracy, it is necessary to spread the biodegradable resin to every corner of the mold, and for that purpose, the atmosphere of the mold during injection is kept in a pressurized state. However, in this case, the injection resistance is further increased, and the above-mentioned problem becomes prominent.

[0011]

[Technical Items Attempted to Develop] The present invention has been made based on such a background, and an object of the present invention is to expand the biodegradable resin after foaming the biodegradable resin. To provide a method for producing a biodegradable resin foam capable of preventing a residual adhesion of water and obtaining a homogeneous foam, and a method for producing a biodegradable resin foam capable of finely and uniformly foaming. To provide a method for producing a biodegradable resin foam capable of obtaining a homogeneous foam in a desired shape with respect to the biodegradable resin, and to provide a method for producing a biodegradable resin foam having water repellency. Even if cavities or voids are created, it is necessary to provide a method for producing a biodegradable resin foam in which mutual walls are bonded to each other as much as possible to prevent the occurrence of discontinuous boundaries. Mutual walls are bonded as much as possible Providing a biodegradable resin foam, capable of rapidly depressurizing and exhausting the atmosphere of the molding die at an appropriate timing without increasing the manufacturing cost of the device, and obtaining a foam of excellent quality It is possible to easily provide a biodegradable resin into a molding die with a small injection resistance without increasing the production cost of the device, and to provide a shape accuracy. It is an object of the present invention to provide a biodegradable resin foam production apparatus capable of obtaining a foam having a high quality. And under such a purpose,
This is an attempt to develop a high-foaming technology for biodegradable resin and a molding technology for molding a biodegradable resin foam into a desired shape.

[0012]

Configuration of the Invention

[Means for Achieving the Object] That is, the biodegradable resin foam according to claim 1 rapidly releases the fluid biodegradable resin in which the water present in the atmosphere under heating and pressurization is trapped. The biodegradable resin foam produced by utilizing the vaporizing and expanding force of water is characterized in that the biodegradable resin is acetate or one containing it.

In addition to the above requirements, the biodegradable resin foam according to a second aspect of the invention is characterized in that the biodegradable resin is a biodegradable resin such as acetate and a biodegradable resin having a melting point not higher than the softening point of the acetate. It is characterized by being composed of a resin.

Further, in the biodegradable resin foam according to claim 3, in addition to the requirement of claim 2, the biodegradable resin having a melting point not higher than the softening point of the acetate contains polycaprolactone or the same. It is characterized by consisting of things.

Furthermore, the biodegradable resin foam according to claim 4 is characterized in that, in addition to the above requirements, polyhydric alcohols and derivatives thereof are added to the biodegradable resin. .

Further, in the method for producing a biodegradable resin foam according to a fifth aspect, a biodegradable resin raw material for foam made of acetate or a material containing the same is charged into a cylinder having a narrowed opening in the front, While pushing the biodegradable resin consisting of acetate or one containing it into the narrowed opening, the temperature of the biodegradable resin is raised so that the biodegradable resin becomes fluid. It is constructed by extruding it into a breathable molding die located abruptly from the heating and pressurizing state in the cylinder, foaming it, and molding it into a shape corresponding to the shape of the molding die. It is characterized by that.

Furthermore, in the method for producing a biodegradable resin foam according to a sixth aspect, in addition to the requirements of the fifth aspect, in extruding the fluidized biodegradable resin into a mold. Before the start of extrusion, or after the start of extrusion, the atmosphere in which the mold is placed is depressurized or ventilated.

Furthermore, in the method for producing a biodegradable resin foam according to claim 7, in addition to the requirements of claim 5 or 6, the fluidized biodegradable resin is extruded into a molding die. In this case, the nozzle provided for the constriction opening is positioned at the inner side of the molding die in the starting state, and the nozzle is retracted relative to the molding die while pushing out the biodegradable resin. It is characterized by having done.

Further, in the method for producing a biodegradable resin foam according to claim 8, in addition to the requirements of claim 5 or 7, the fluidized biodegradable resin is extruded into a molding die. In this case, the atmosphere in the molding die is kept pressurized while being extruded, and the atmosphere in the molding die is rapidly depressurized after the extrusion is completed.

Further, in the method for producing a biodegradable resin foam according to claim 9, the fluidized biodegradable resin is molded in addition to the requirements of claim 5, 6, 7 or 8. When extruding into the mold, the biodegradable resin is injected from the narrowed opening into the mold in an atomized state.

[0021] Furthermore, the method for producing a biodegradable resin foam according to claim 10 is the method according to claim 5, 6, 7, 8 or 9.
In addition to the requirements described, the biodegradable resin raw material for the foam,
It is characterized in that it is composed of water and acetate or a biodegradable resin composed of one containing water.

Further, the method for producing a biodegradable resin foam according to claim 11 is the method according to claim 5, 6, 7, 8 or 9.
In addition to the requirements described, the biodegradable resin raw material for the foam,
It is characterized in that a hygroscopic fine particle substance is made to absorb water and then added to the biodegradable resin.

Furthermore, the method for producing a biodegradable resin foam according to a twelfth aspect of the present invention is the method of the fifth, sixth, seventh, eighth or ninth aspect.
In addition to the requirements described, the biodegradable resin raw material for the foam,
It is characterized in that it is composed of water and a water repellent substance of acetate or a biodegradable resin containing the same.

Furthermore, the method for producing a biodegradable resin foam according to a thirteenth aspect is the method according to the fifth, sixth, seventh, eighth, ninth and first aspect.
In addition to the requirements of 0, 11 or 12, when molding the foamed biodegradable resin into a shape corresponding to the mold shape of the molding die, the foamed raw material extruded into the molding die is used. It is characterized in that all of the decomposable resin is molded into an integral shape.

Furthermore, the method for producing the biodegradable resin foam according to claim 14 is the method according to any one of claims 5, 6, 7, 8, 9,
In addition to the requirements described in 10, 11, 12 or 13, the biodegradable resin is composed of acetate which is a biodegradable resin and a biodegradable resin having a melting point equal to or lower than the softening point of the acetate. It is a feature.

Furthermore, the method for producing a biodegradable resin foam according to claim 15 is, in addition to the requirements of claim 14,
The biodegradable resin having a melting point not higher than the softening point of acetate is polycaprolactone or a resin containing polycaprolactone.

Furthermore, the method for producing a biodegradable resin foam according to claim 16 is the method according to claim 5, 6, 7, 8, 9, 1
In addition to the requirements described in 0, 11, 12, 13, 14, or 15, polyhydric alcohols and their derivatives are added to the biodegradable resin.

The biodegradable resin foam manufacturing apparatus according to claim 17 further comprises a pressure adjusting chamber capable of opening and closing and sealing.
A gas permeable mold placed in the pressure adjusting chamber, a decompression tank for rapid decompression connected to the pressure adjusting chamber, and a fluid state in which water existing in an atmosphere in a heated and pressurized state is trapped in the mold. And an injection machine for injecting a biodegradable resin consisting of the above-mentioned acetate or one containing the same.

Furthermore, in the apparatus for producing a biodegradable resin foam according to claim 18, in addition to the requirements of claim 17,
An exhaust valve is connected to the pressure adjusting chamber.

Furthermore, the apparatus for producing a biodegradable resin foam according to claim 19 is characterized in that, in addition to the requirements of claim 17 or 18, a compressor is connected to the pressure adjusting chamber. It is a thing.

Furthermore, the apparatus for producing a biodegradable resin foam according to claim 20 is characterized in that, in addition to the requirements of claim 17 or 18, a pressure tank is connected to the pressure adjusting chamber. It consists of

Furthermore, the apparatus for producing a biodegradable resin foam according to a twenty-first aspect is provided with a pressure adjusting chamber that can be opened and closed and sealed.
An air-permeable mold disposed in the pressure adjusting chamber, a decompression tank for rapid depressurization connected to the pressure adjusting chamber via a depressurizing valve, an exhaust valve connected to the pressure adjusting chamber, A compressor connected to the pressure adjustment chamber,
A valve controller for controlling the opening and closing of each of the valves, and for injecting into the mold a biodegradable resin consisting of a fluid acetate in which water present in an atmosphere under heating and pressurization is contained or a fluid containing acetate. The valve controller starts the pressurizing operation of the compressor at or before the start of the injection of the biodegradable resin into the mold by the injection machine, and the compressor of the compressor is started during the injection. The present invention is characterized in that the pressurizing operation is stopped and the exhaust valve is opened, and after the injection, the exhaust valve is closed and the depressurizing valve is opened.

Furthermore, the apparatus for producing a biodegradable resin foam according to a twenty-second aspect is provided with a pressure adjusting chamber that can be opened and closed and sealed.
An air-permeable mold disposed in the pressure adjusting chamber, a decompression tank for rapid depressurization connected to the pressure adjusting chamber via a depressurizing valve, an exhaust valve connected to the pressure adjusting chamber, A pressure tank connected to the pressure adjusting chamber via a pressurizing valve, a valve controller for controlling the opening and closing of each of the valves, and a flow in which water existing in an atmosphere in a heated and pressurized state is trapped in the mold. An injecting machine for injecting a biodegradable resin composed of acetate in the form of or containing the same, the valve controller being at the start of injecting the biodegradable resin into the mold by the injecting machine or It is configured to open the pressurization valve before that, close the pressurization valve during the injection and open the exhaust valve, and after the injection, close the exhaust valve and open the decompression valve. It is those made as.

Furthermore, the apparatus for producing a biodegradable resin foam according to a twenty-third aspect is provided with a pressure adjusting chamber that can be opened and closed and sealed.
An air-permeable mold disposed in the pressure adjusting chamber, a decompression tank for rapid depressurization connected to the pressure adjusting chamber via a depressurizing valve, an exhaust valve connected to the pressure adjusting chamber, A valve controller for controlling the opening and closing of each valve, and for injecting into the mold a biodegradable resin consisting of a fluid acetate in which water present in an atmosphere under heating and pressurization is contained or a fluid containing acetate. An injector is provided, and the valve controller opens the exhaust valve during the injection of the biodegradable resin into the mold by the injector, and after the injection, closes the exhaust valve and opens the pressure reducing valve. It is characterized by being configured as follows.

Furthermore, the apparatus for producing a biodegradable resin foam according to a twenty-fourth aspect of the present invention comprises a pressure adjusting chamber that can be opened and closed and sealed.
An air-permeable mold disposed in the pressure adjusting chamber, a decompression tank for rapid decompression connected to the pressure adjusting chamber via a pressure reducing valve, and a pressure reducing chamber connected to the pressure adjusting chamber via a pressurizing valve. A pressure tank, a valve controller for controlling the opening and closing of each of the valves, and a biodegradable substance consisting of a fluid acetate in which water existing in an atmosphere in a heating and pressurizing state is trapped in the molding die or containing the same. An injection machine for injecting the resin, wherein the valve controller opens the pressurizing valve at or before the injection of the biodegradable resin into the mold by the injection machine and opens the injection machine. The pressure reducing valve is closed and the pressure reducing valve is opened.

Furthermore, the apparatus for producing a biodegradable resin foam according to a twenty-fifth aspect is the apparatus for producing the biodegradable resin foam according to the seventeenth, eighteenth, nineteenth and second aspects.
In addition to the requirements described in 0, 21, 22, 23, or 24, the injector has a cylinder having a narrowed opening in the front and a biodegradable resin for a foam, which is made of acetate or a mixture containing acetate. A pushing mechanism for pushing the raw material and pushing out a biodegradable resin consisting of acetate or a fluid containing it, which is fluidized by heating, into the molding die, and the narrowing opening and the molding die. It is characterized in that it comprises a moving mechanism for relatively retracting the constriction opening with respect to the molding die, while pushing out the biodegradable resin in a fluid state which is relatively advanced and retracted from the constriction opening into the molding die. It consists of Then, the object of the invention is to be achieved by using the constitution of the invention described in each of these claims.

[0037]

The biodegradable resin foam according to any one of claims 1 to 4 is characterized in that the biodegradable resin foam is composed of acetate or one containing the same, and the biodegradable resin foam according to claim 2 is further provided. The biodegradable resin is composed of acetate, which is a biodegradable resin, and biodegradable resin having a melting point not higher than the softening point of the acetate. As a result, the low melting point biodegradable resin having a melting point equal to or lower than the softening point of acetate does not solidify immediately, and functions as an adhesive to the main component biodegradable resin, acetate. Therefore, it is possible to obtain a biodegradable resin foam in which mutual walls are bonded to each other as much as possible even if voids or voids are generated. In particular, when polycaprolactone or one containing it is used as the low melting point biodegradable resin having a melting point equal to or lower than the softening point of acetate, the function as the adhesive is sufficiently exerted, and the biodegradable resin further contains a plasticizer. When a certain polyhydric alcohol and its derivative are added, the boiling point of water in the biodegradable resin rises, so that the foamed cell becomes dense and uniform.

In the method for producing a biodegradable resin foam according to a fifth aspect of the present invention, the biodegradable resin composed of acetate or a fluidized acetate which is heated and fluidized is rapidly released from a heated and pressurized state. At the same time, it is further extruded into a breathable mold to be molded into a predetermined shape. As a result, the water contained in the biodegradable resin has a boiling point increased by pressurization, so that it exists as a liquid in the cylinder, and the water is momentarily released after being rapidly released from the heating and pressurizing state. Upon evaporation, the biodegradable resin is foamed. Further, the water vapor generated at this time is released to the outside because the mold has air permeability, and does not adhere to the produced biodegradable resin foam.

In the method for producing a biodegradable resin foam according to a sixth aspect of the present invention, the atmosphere in which the mold is placed is a reduced pressure or ventilation atmosphere before or after the extrusion of the biodegradable resin is started. To take. As a result, the water inside the mold is vaporized and expanded, and then cooled down and drifts in a steam state, and it is excluded to the outside without condensing and forming water drops by touching the outside of the mold and the biodegradable resin foam. . Therefore, the removal of residual water and the drying work are unnecessary.

According to a seventh aspect of the present invention, in the method for producing a biodegradable resin foam, the nozzle provided for the narrowed opening is positioned on the inner side of the mold in the starting state and the biodegradable resin is extruded. However, the configuration is such that it is set back relative to the molding die. As a result, the biodegradable resin is sequentially filled from the back side of the mold, so that the difference between the timing of reaching the details and every corner of the mold and the timing of foaming is reduced or substantially eliminated. As a result, the foam cells spread to every detail and every corner in the mold, and therefore, the collapse of the foam cells can be prevented as much as possible, so that a biodegradable resin foam having a desired shape and uniform can be obtained.

In the method for producing a biodegradable resin foam according to claim 8, the atmosphere in the molding die is kept under pressure while the biodegradable resin is extruded into the molding die, and after the extrusion is completed. Has a structure in which the pressure is rapidly reduced. As a result, the biodegradable resin is extruded into the mold in a state where the water is trapped, and after the pressure is reduced, the water is instantaneously evaporated to foam the biodegradable resin. Therefore, the biodegradable resin foams in a state where it reaches every corner of the mold, so that a uniform biodegradable resin foam having a desired shape can be obtained.

A method for producing a biodegradable resin foam according to a ninth aspect of the present invention has a structure in which the biodegradable resin is injected into the mold through a narrowing opening in an atomized state. As a result, the biodegradable resin in the atomized state spreads to every corner in the mold, and is rapidly released from the heating and pressurizing state, and the water trapped inside expands and expands at once. While the evaporated water is released outside the breathable mold, the biodegradable resin in the atomized state foams and collects, and the biodegradation is uniform in the desired shape without crushing the foam cells. A resin foam is obtained.

The method for producing a biodegradable resin foam according to any one of claims 10 to 12, wherein the biodegradable resin raw material for foam is water and acetate, or a biodegradable resin containing the same, hygroscopic fine particles. It is composed of a substance in which water is absorbed in a particulate substance, the biodegradable resin or moisture, the biodegradable resin and a water repellent substance. As a result, desired foaming can be expected, and if a hygroscopic fine particle substance that has absorbed water is added to the biodegradable resin in advance, the fine particles have compatibility with the biodegradable resin and dispersibility. Is higher than that of direct addition of water, and the water in the fine particles can be foamed with the fine particles as a base point during foaming, and as a result, a finely and uniformly foamed biodegradable resin foam can be obtained. Further, as the water-repellent substance, a substance having a boiling point that does not completely evaporate when released from the heated and pressurized state, for example, a natural fatty acid polymer is used, and the water-repellent substance covers each membrane of the foamed cell. Biodegradable resin foam has water repellency,
Removal of residual water and drying work become easy.

A method for producing a biodegradable resin foam according to a thirteenth aspect has a structure in which all of the foamed biodegradable resin extruded into a molding die is molded into an integral shape. This makes it possible to form a biodegradable resin foam having a relatively large volume and also to form biodegradable resin foams of various shapes.

In the method for producing a biodegradable resin foam according to claims 14 to 16, the same action as that described in the biodegradable resin foam according to claims 1 to 4 can be obtained.

According to the apparatus for producing a biodegradable resin foam according to the seventeenth aspect, the water present in the heated and pressurized atmosphere is trapped by the pouring machine in the air-permeable mold disposed in the pressure adjusting chamber. When a biodegradable resin composed of fluid acetate or one containing it is injected, and then the decompression tank is communicated with the pressure adjusting chamber, the biodegradable resin is rapidly released from the heating and pressurizing state. The water trapped inside expands and expands in an attempt to evaporate at once.
Further, since the pressure can be rapidly reduced by the decompression tank at an appropriate timing, the moisture is rapidly diffused to the outside of the air-permeable mold, and there is no possibility that the moisture remains in the mold. Therefore, a uniform biodegradable resin foam made of the biodegradable resin having a shape corresponding to the molding die is formed in the molding die, and residual water removal and drying operations are unnecessary.

According to the apparatus for producing a biodegradable resin foam according to claim 18, when the pressure adjusting chamber is opened by the exhaust valve while the biodegradable resin is being injected by the injection machine,
Since the molding die is breathable, the injection resistance of the biodegradable resin is alleviated, and the injection can be performed easily. Therefore, it is possible to prevent the injector from becoming large.

According to the biodegradable resin foam manufacturing apparatus of the nineteenth aspect, since the compressor is connected to the pressure adjusting chamber, when the biodegradable resin is injected by the injection machine, first the compressor is operated by the compressor. When the pressure adjusting chamber is kept under pressure, the biodegradable resin can be injected in a state where water is surely trapped, and when the pressure adjusting chamber is then opened by the exhaust valve, the injection resistance is alleviated.
The biodegradable resin can be easily spread to every corner of the mold.

According to the biodegradable resin foam manufacturing apparatus of the twentieth aspect, since the pressure adjusting chamber is connected to the pressure adjusting chamber, the pressure adjusting chamber is opened at an appropriate timing during injection by the injection machine. The pressure can be rapidly increased.

According to the apparatus for producing a biodegradable resin foam of the twenty-first aspect, since the valve controller for controlling the opening / closing of the pressure reducing valve and the exhaust valve and the pressurizing operation of the compressor is provided, the injection machine is provided. According to the timing of injection of the biodegradable resin consisting of acetate or a resin containing the same, the pressure adjusting chamber can be surely controlled to the pressurized, exhausted, and depressurized states.

According to the apparatus for producing a biodegradable resin foam according to the twenty-second aspect, since the valve controller for controlling opening / closing of the pressure reducing valve, the exhaust valve and the pressurizing valve is provided, the acetate by the injection machine is used. Alternatively, it is possible to reliably control the pressure adjusting chamber to the pressurized, exhausted, and depressurized states in accordance with the timing of injecting the biodegradable resin containing the same.

According to the apparatus for producing a biodegradable resin foam according to the twenty-third aspect, since the valve controller for controlling the opening and closing of the pressure reducing valve and the exhaust valve is provided, acetate containing an injector or the same is included. It is possible to reliably control the pressure adjustment chamber to the exhaust or decompression state in accordance with the timing of injecting the biodegradable resin made of a material.

According to the biodegradable resin foam manufacturing apparatus of the twenty-fourth aspect, since the valve controller for controlling the opening and closing of the pressure reducing valve and the pressurizing valve is provided, the acetic acid by the injection machine or the acetic acid-containing valve is included. It is possible to reliably control the pressure adjusting chamber to each state of pressurization and depressurization in accordance with the timing of injecting the biodegradable resin made of a material.

According to the apparatus for producing a biodegradable resin foam according to the twenty-fifth aspect, the same operation as that described in the method for producing a biodegradable resin foam according to the seventh aspect can be achieved.

[0055]

The biodegradable resin foam of the present invention, a method for producing the same, and an apparatus for producing the same will be specifically described below with reference to the drawings. In the explanation, first, the constitution of the biodegradable resin foam of the present invention will be explained, and then various examples of the production method of the present invention will be explained together with the constitution of the production apparatus used in each example, and then the molding die. After describing various embodiments of the manufacturing apparatus of the present invention characterized by the pressure adjusting mechanism in the inside, and further explaining another manufacturing method of the present invention using this manufacturing apparatus, finally, the volume of the molding space Reference will be made to an embodiment of a manufacturing apparatus and an embodiment of a manufacturing method in which the above can be varied.

(1) Examples of biodegradable resin foams according to claims 1 to 4 The biodegradable resin foam B according to the present invention according to claims 1 to 4 comprises:
The biodegradable resin foam according to claim 2, which is obtained by foaming a biodegradable resin by utilizing vaporization and expansion force of water, wherein acetate or a material containing the same is used as the biodegradable resin. In the body B, a biodegradable resin (main component biodegradable resin), acetate, and a biodegradable resin (low melting point biodegradable resin) having a melting point not higher than the softening point of the acetate are used. It is made of degradable resin.

In general, a biodegradable resin means a resin material whose physical properties are deteriorated due to a biological action. This includes a type in which the resin itself is completely decomposed and a resin in which it is difficult to decompose, and which is disintegratable. There is a type that is given. The former type includes products produced by microorganisms, products using natural polymers, products derived from petroleum-based raw materials, and the latter types include blends with starch and blends with aliphatic polyesters. As the biodegradation mechanism of these, lipase,
There are various modes such as decomposition with enzymes such as amylase, cellulase, and protease, decomposition with microorganisms such as in activated sludge, and decomposition with soil in a natural environment such as forest and cultivated land.

More specifically, polyhydroxybutyric acid and its derivatives, pullulan, cellulose-chitosan mixture,
Ester compounds of cellulose, amylose and wood flour, polyester-nylon copolymer, polyester copolymer,
Examples include blends of starch and polyethylene, polyvinyl alcohol, polyether, polyurethane, polyamide and the like. Most of these have a low melting point and are accelerated in the presence of water.

In the present invention, acetate which is an ester compound of cellulose is used as a biodegradable resin or as a part thereof. And such an acetate, or a biodegradable resin containing the same, is decomposed by an enzyme possessed by a microorganism in the natural world, and is taken back into a plant or a microorganism as a nutrient source, and in Japan, Teijin acetate or the like is produced, We are selling.

Further, the low melting point biodegradable resin having a melting point not higher than the softening point of acetate described in claim 2 or 3,
Even if voids or voids are created during molding of the foam,
The mutual walls are associated with each other as much as possible, and for example, polycaprolactone or one containing the same can be preferably used. Further, as a commercially available product of such a low melting point biodegradable resin, there is, for example, "Tone" (trade name) sold by Nippon Unicar Co., Ltd. This "tone" is a chemically synthesized aliphatic polyester made of polycaprolactone, which is a completely degradable biodegradable resin.

Further, in the present invention, polyhydric alcohols and their derivatives can be added to these biodegradable resins, if necessary. Particularly glycols can be preferably used. When the polyhydric alcohol and its derivative are added, the boiling point of water in the biodegradable resin rises, and since the polyhydric alcohol and its derivative itself are plasticizers, the foamed cells become dense and uniform. Examples of such polyhydric alcohols and their derivatives include glycerin and polyethylene glycol.

The means for allowing water to exist in the biodegradable resin is not particularly limited, but an appropriate amount of water may be contained in advance when the biodegradable resin pellet for foaming is molded. Alternatively, a pretreatment step of positively containing water in the biodegradable resin granules may be provided. Further, the water itself may be directly added to the hopper together with the biodegradable resin, or may be supplied into the cylinder through a kneader, and the biodegradable resin and the water may be substantially supplied. If a biodegradable resin is added with a hygroscopic particulate substance that has previously absorbed water, such as foaming pellets, such as talc (talc) or silica, the particulate will have a compatibility and dispersibility with the resin. Since the water content is higher than that of the direct addition of water, and the water content in the fine particles can be foamed starting from the fine particles at the time of foaming, and as a result, a finely and uniformly foamed product can be obtained.

The biodegradable resin foam B of the present invention is obtained by foaming a fluid biodegradable resin containing water present in an atmosphere under heating and pressurization by utilizing the vaporizing and expanding force of water. The temperature of the foam is 100 ° C because it loses the heat of vaporization.
Descend to a degree. At this time, in the biodegradable resin foam B according to claim 2, the main component biodegradable resin, acetate, is solidified, but the low melting point biodegradable resin having a melting point not higher than the softening point of the acetate is immediately obtained. Never solidifies,
In other words, it will function as an adhesive for the main component biodegradable resin. Therefore, even if voids or voids are formed during the molding of the biodegradable resin foam of the present invention, the mutual walls are bonded to each other as much as possible, so that the biodegradable resin foam B of good quality can be obtained.

When the biodegradable resin raw material for foam in the biodegradable resin foam B of the present invention is composed of water, the biodegradable resin and a water repellent substance, the biodegradable resin is a water repellent substance. In order to put it in a heating and pressurizing state in the presence of water and substantial moisture, for example, a water-repellent substance is added to the biodegradable resin in advance and made to contain moisture, and this is put into, for example, an injection molding machine as an injection machine. You may do it. As the water-repellent substance, silicone compounds, fluorine compounds,
Waxes or polymers of higher fatty acids are used, but in this example, a product name "Sigma Coat" (natural product of natural higher fatty acids and waxes) (manufactured by Sigma Technical Research Institute Co., Ltd .: Tonen Corporation) Sales). As a method of adding a water-repellent substance to a biodegradable resin, for example, the water-repellent substance (trade name "Sigma Coat")
Can be diluted with water and heated to form an emulsion, which can be added as this emulsion. By doing so, the biodegradable resin can simultaneously contain the water-repellent substance and water. Further, the step of incorporating the water-repellent substance and the water into the biodegradable resin may be carried out separately. For example, a method of mixing the water-repellent substance with the water-containing biodegradable resin may be adopted. it can. In addition, the biodegradable resin foam B of the present invention is not limited to the use as a cushioning material, and can be used for the same applications as conventional styrofoam such as a heat insulating material and a soundproof material. .

(2) Embodiments of the manufacturing method according to claims 5, 6, 10, 11, and 13 Next, various embodiments of the manufacturing method of the present invention will be described together with the structure of the manufacturing apparatus used in each embodiment. . First, a manufacturing apparatus used in the embodiment of the present invention will be described with reference to FIG. In the figure, reference numeral 1 is a cylinder having a cylindrical container shape, and a hopper 11 for introducing a biodegradable resin raw material for foam is provided above the rear end of the cylinder. A constriction opening 1a is formed at the front end of the cylinder 1, and
A heater 13 for heating is arranged around the cylinder 1.

A screw 2 extending in the front-rear direction is disposed in the cylinder 1 close to the inner wall thereof, and the rear end of the screw 2 extends rearward from the rear end opening of the cylinder 1. , Is connected to a hydraulic motor 21 for rotating the screw 2. Further, a piston 23 slidably arranged in the injection cylinder 22 is attached to the rear part of the hydraulic motor 21, and therefore the piston 23, the hydraulic motor 21 and the screw 2 are integrally moved by the hydraulic pressure in the front-rear direction. At the same time, the screw 2 is rotated by the hydraulic motor 21.

Thus, a so-called in-line screw type injection molding machine is constructed, and a breathable molding die A is arranged at the tip of this injection machine S, and this molding die A has the narrowed opening. Cavity 31 communicating with 1a
And a movable-side mold 4 having a core 41 formed therein. In this embodiment, the cavity 31 has a substantially triangular pyramid shape, and the core 41 has a substantially triangular pyramid shape smaller than the shape of the cavity 31 by the thickness of the molded product. A three-sided structure space orthogonal to each other is formed so that a biodegradable resin foam B shown in FIG. 3 described later can be obtained when tightened.

A mold clamping mechanism 40 is provided in combination with the molding die A. The mold clamping mechanism 40 guides, for example, the movable side mold 4 so as to come into contact with and separate from the fixed side mold 3 while facing them. The tie bars 42 and 43 and the operating mechanism 44 for moving the movable die 4 into and out of contact with each other are included.

The molding die A is made of a porous material having an infinite number of network-like pores that communicate the inside and the outside almost all over. This porous material includes metal foam,
It is possible to use a sintered product such as a metal or ceramics sintered by adding a filler capable of forming voids, a wire mesh, a punching metal, etc., which are press-molded and laminated. As a simple structure, a punched metal sheet formed into a predetermined shape can be used. Here, if the pores of the porous material are large, the steam discharge efficiency and the ventilation efficiency are good, but if they are too large, the surface of the molded body after foaming becomes strongly uneven due to the pores and the surface becomes rough. Therefore, the size of the pores of the porous material is within a range in which the smoothness of the surface according to the use of the molded product can be obtained, and is set in a range in which the ventilation resistance does not become too large, and the preferable pore diameter is Since the number of holes, the hole pitch, etc. can be easily set and the structure is simple, the one using the punching metal as mentioned above can be mentioned.

The mold A and the mold clamping mechanism 40 are arranged in the chamber 5 which is a pressure adjusting chamber having an airtight structure.
The chamber 5 has a wall portion joined to the back surface of the stationary mold 3 and a door (not shown) for taking out a biodegradable resin molding. The chamber 5 is connected with a decompression pipe L _{1 including} a decompression valve V ₁ and a decompression pump P ₁ , and the chamber 5
Atmospheric pressure relief pipe L ₀ which comprises the atmospheric pressure relief valve V ₀ in order to open the atmospheric pressure inside the reduced pressure is connected.

The manufacturing method of the present invention will be described using the manufacturing apparatus having the above-described structure. First, the mold A is clamped, and the pressure reducing valve V ₁ is closed to set the chamber 5 in an atmospheric pressure state. 1 and the hopper 11 as shown in FIG.
Water and granules 10 of biodegradable resin are supplied therein, and the screw 2 pushes the inside of the cylinder 1 forward. While being fed, the biodegradable resin granules 10 are heated to a temperature around the softening point or the melting point due to the shearing force accompanying the rotation of the screw 2 and the heating from the inner wall of the cylinder 1 by the heater 13. Is accumulated in the inner space of the cylinder 1 on the leading end side in the form of a fluid.

At this time, since the internal space is in a heated and pressurized state, the water contained in the biodegradable resin granules 10 does not evaporate from the fluidized biodegradable resin and enters it. It is in a trapped state. Then, the rotation of the screw 2 is stopped, and the piston 2 in the injection cylinder 22 is stopped.
3 is operated to advance the screw 2 as shown in FIG. 2 (a), and the fluid biodegradable resin is injected into the molding space R in the molding die A at once from the narrowing opening 1a.

As a result, the biodegradable resin is rapidly exposed to the atmospheric pressure from the heated and pressurized state, so that the water trapped therein is instantaneously evaporated and foamed. The expanding force of the water vapor acts in the biodegradable resin, but the outermost portion of the biodegradable resin is in contact with the mold A, so that it is restricted by the shapes of the cavity 31 and the core 41. Thus, for example, as shown in FIG. The biodegradable resin foam B molded into an integral shape is obtained.

At this time, in the vicinity of the inside and outside of the molding die A, the water vaporizes and expands and then drops in temperature and drifts in a steam state, or touches the outer peripheral portion of the molding die A and the molded body to condense and become water droplets. Immediately after the biodegradable resin has been extruded into the mold A, the pressure reducing valve V ₁ is opened as shown in FIG. 2 (b), and the pressure inside the chamber 5 is adjusted to about 750 mmHg by the pressure reducing pump P ₁ , for example. Evacuate to vacuum. In this case, a part of the water vapor is sucked into the depressurizing pipe L ₁ before being formed into water droplets, and the moisture that is about to be condensed into water droplets due to dew condensation on the outer periphery of the mold A and the biodegradable resin foam B as a molded body is also reduced. It will be vaporized and removed.

After decompressing and exhausting for a predetermined time, the decompression valve V ₁ is closed, the atmospheric pressure release valve V ₀ is opened, and air is introduced into the chamber 5 through the atmospheric pressure release pipe L ₀ , and the pressure inside the chamber 5 is reduced to atmospheric pressure. Back to the screw 2 as shown in Figure 2 (c).
The resin is made to retreat while rotating, whereby the biodegradable resin that has become fluid again begins to accumulate in the internal space of the cylinder 1 on the tip side of the screw 2 and prepares for the next injection. During this time, in the molding space R in the molding die A, the cooling and solidification of the biodegradable resin foam B after molding is completed, so the molding die A is opened to take out the biodegradable resin foam B, and the mold is re-molded. Tighten and perform the following operation.

Since at least a part of the mold A is made of a continuous porous material to obtain air permeability, the gas pressure generated at the time of expansion should be appropriately released to the outside of the mold A. Since it does not crush the foamed biodegradable resin with its own gas pressure, a uniformly foamed molded body can be obtained as a whole and can be used as a homogeneous cushioning material.
Immediately after the extrusion of the biodegradable resin, the chamber 5 is evacuated to a reduced pressure to forcibly remove the water content that has contributed to the foaming as described above, and therefore the residual water content removal and drying operations are unnecessary. , Improve work efficiency.

Further, in this embodiment, as described in claim 11, for a foam obtained by absorbing moisture in advance in a hygroscopic fine particle substance and dispersing it in a biodegradable resin as described above. A biodegradable resin raw material can also be used as a foaming grade. In this case, in the fluid biodegradable resin extruded from the injecting machine S, water is carried on the fine particles and dispersed with high uniformity, and since the water is foamed starting from the fine particles, it is fine and uniform. It can be foamed.

In the above, as an apparatus for carrying out the present invention, as shown in, for example, FIG. 4, the chamber 5 is divided into a movable side dividing portion 51 and a fixed side dividing portion 52, and the movable side dividing portion 51 is provided with a movable side metal member. It may be configured to be movable integrally with the mold 4. With this structure, the molding die A and the chamber 5 can be opened and closed at the same time, and thus the biodegradable resin foam B
Is easy to take out.

The timing of decompression exhaustion in the chamber may be before the biodegradable resin is extruded through the narrowed opening 1a, during the extrusion, or after the extrusion is completed.
Instead of exhausting the atmosphere surrounding the molding die A under reduced pressure, for example, as shown in FIG. 5, the molding die A is arranged in the ventilation duct D, and the suction fan f provided therein ventilates the ventilation duct D. However, by doing so, the moisture in the molding die A may be removed to suppress contact with the moisture.

Here, the constriction opening 1a is open, and the hopper 11 on the raw material supply side of the cylinder 1 is also open. Although a certain degree of hermeticity is secured by the raw material and the molten resin, the hermetically sealed interior of the cylinder 1 is obtained. If the property is low, pressurization will be insufficient, and due to the balance between the softening point or melting point of the biodegradable resin and the boiling point of water under pressure, some water vaporizes and foams in the cylinder 1 before injection. There is a possibility that there is a risk of stenosis 1
It may foam in a dripping state from a. In view of this, in this embodiment, a nozzle provided with a shut-off valve is provided for the constriction opening 1a, the hopper 11 on the raw material supply side is sealed, and further, a rotary valve is attached to the raw material supply port to improve the hermeticity. It is preferable to increase. Alternatively, for example, a non-volatile solute such as polyethylene glycol may be dissolved in water, and this aqueous solution may be added to raise the boiling point of water to suppress foaming in the cylinder 1 before injection. .

In the above method of adding the hygroscopic fine particle substance, the manufacturing process of the biodegradable resin foam B is not limited to the method of extruding the biodegradable resin foam B into the molding die A from the injection molding machine such as the injection machine S, but it is hermetically sealed. The mold A is placed in the heated container, and the fine particle substance is dispersed in the biodegradable resin in advance. After heating steam is supplied to the heating container, the inside of the heating container is rapidly cooled. You may make it decompress. The hygroscopic particulate substance is not limited to the round powder, but may be in the form of a strip or a rod.

In this example, it is not always necessary to add a hygroscopic fine particle substance to the biodegradable resin. In this case, the biodegradable resin may be preliminarily hydrated, or equilibrated under atmospheric pressure. A biodegradable resin containing water may be used, or the biodegradable resin and water may be independently charged into the hopper 11.

(3) A manufacturing method according to claim 7, claim 2
Embodiment 5 of the manufacturing apparatus according to claim 5 Prior to the description of the embodiment of the manufacturing method according to claim 7, a manufacturing apparatus according to claim 25 used in this embodiment will be described with reference to FIG. Since the basic structure of the manufacturing apparatus is the same as that of the manufacturing apparatus shown in FIG. 1, the details thereof will be omitted here and only different points will be described.

That is, in the case of the embodiment shown in FIG. 6, a longer nozzle 12 is provided for the constriction opening 1a, and accordingly, a heater 13 is also installed around the cylinder 1. Besides, it is of course possible to incorporate the nozzle into the nozzle 12. Further, an insertion hole 32 communicating with the cavity 31 is formed in the wall portion of the front surface (surface on the injection machine S side) of the stationary mold 3 so that the nozzle 12 can be inserted therethrough.

Further, in this embodiment, the mold A and the mold clamping mechanism 40 are placed and fixed on the movable table 6,
The moving table 6 includes wheels 62 and 63 that roll along a guide rail 61. A frame plate portion 64 is attached to the rear end portion (the left end portion in FIG. 6) of the movable table 6, and the frame plate portion 64 is located in front of the frame plate portion 64 and is attached to a piston 66 moving in a hydraulic cylinder 65. It is connected. The hydraulic cylinder 65 is fixed to a bearing stand (not shown) or the like, and the hydraulic pressure is applied to the piston 66 to move the moving stand 6. In this embodiment, the movable table 6 and the guide rail 6 are used.
The moving mechanism 60 is composed of the wheel 1, the wheels 62 and 63, the frame plate portion 64, the hydraulic cylinder 65, and the piston 66.
However, in this embodiment, the hydraulic cylinder 65 and the piston 6
The movable table 6 may be moved in a free state due to the pushing pressure of the biodegradable resin without providing 6; however, in this case, for example, as shown in FIG. The braking mechanism 7 using the electromagnet may be provided, for example, on the wheels 62 to control the backward speed of the moving table 6.

The manufacturing method of the present invention will be described using the manufacturing apparatus having the above-described structure. First, the molding die A is clamped, and the constriction opening 1a is opened as shown in FIG. The movable table 6 is set to the forward position so that the tip of the nozzle 12 provided to the opposite side is located on the back side of the molding die A. This position setting can be performed by providing a stopper on the guide rail 61, for example. Then, as shown in FIG. 6, particles 10 of water and biodegradable resin are supplied into the hopper 11, and the inside of the cylinder 1 is pushed forward by the screw 2. The biodegradable resin granules 10 are sheared by the rotation of the screw 2 and the heater 13 while being pushed.
By the heating from the inner wall of the cylinder 1 by the above, the temperature is raised to a temperature around the softening point or the melting point, and the fluid is accumulated in the internal space of the cylinder 1 on the tip side of the screw 2.

At this time, since the internal space is in a heated and pressurized state, the water contained in the biodegradable resin granules 10 does not evaporate from the fluid biodegradable resin and enters it. It is in a trapped state. Then, the rotation of the screw 2 is stopped, and the piston 2 in the injection cylinder 22 is stopped.
3 is operated to advance the screw 2 as shown in FIG. 7A, and the fluid biodegradable resin is injected from the nozzle 12 into the molding space R in the molding die A at a stroke.

As a result, the biodegradable resin is rapidly exposed to the atmospheric pressure from the heated and pressurized state, so that the trapped water is instantaneously evaporated and foamed, and the hydraulic pressure of the hydraulic cylinder 65 causes The molding die A retracts to the rear side (left side in FIG. 7), and as a result, the biodegradable resin foams while being extruded from the back side of the molding die A in sequence. The reverse speed of the forming die A is determined by the hydraulic cylinder 65.
It is adjusted by the hydraulic control in, but if the speed is too fast, the amount of biodegradable resin extruded to the front side of the molding die A is too large, and foaming occurs on the front side than expected,
On the other hand, if the speed is too slow, the foam cells that have foamed on the back side of the mold A will be crushed by the subsequent extrusion of the biodegradable resin. It is desirable to determine the retreat speed of the mold A so that the mold A is extruded by an appropriate amount. Then, the force of water vapor expansion works in the biodegradable resin, but since the outermost part of the resin is in contact with the mold A, the shape of the cavity 31 is restricted, while the water vapor passes through the porous portion of the mold A. Of the biodegradable resin foam B, which is diffused to the outside and thus molded as a whole. On the other hand, as shown in FIG. 7 (c), the biodegradable resin which has become fluid again during the backward movement while rotating the screw 2 starts to accumulate in the internal space of the cylinder 1 on the tip side of the screw 2 and the next injection Prepare for During this time, in the cavity 31 of the molding die A, since the cooling and solidification of the biodegradable resin foam after molding is completed, the molding die A is opened and the biodegradable resin foam B is taken out and clamped again. And perform the following operations.

In the above embodiment, the nozzle 12 is
First, since the nozzle 12 is retracted while pushing the biodegradable resin into the molding die A while being positioned at the back side of the molding die A, the inner surface of the molding die A in which the biodegradable resin is clogged from now on. The biodegradable resin is extruded in a state where the extrusion port of the nozzle 12 and the extrusion port of the nozzle 12 are close to each other. For this reason, since the foaming is completed with the biodegradable resin entering every corner of the molding die A, the foaming cells are accumulated in the position floating from the inner surface of the mold and forcedly pushed by the biodegradable resin from behind. Since it is possible to alleviate or avoid the problem of being crushed by crushing, and thus to suppress the crushing of the foam cells once foamed, it is possible to obtain a homogeneous biodegradable resin foam B with a desired shape. Sufficient buffering performance can be obtained.

When the molding die A and the nozzle 12 are relatively advanced and retracted as described above, the injection machine S side may be configured to be movable back and forth instead of the molding die A side to be movable back and forth. The nozzle 12 may be configured to move back and forth, or the nozzle 12 may expand and contract while maintaining airtightness. If the speed of relative movement between the mold A and the nozzle 12 is controlled by, for example, a hydraulic cylinder, the foaming density (filling degree) can be controlled. Therefore, for example, the surface of the mold A is hard and the inner layer is soft. You can also say

Here, regarding the nozzle 12, the diameter of the extrusion port may be considerably reduced so that the biodegradable resin is sprayed in the form of mist. By doing so, a molding die A having a more complicated shape can be obtained. There is an advantage that it can cope. Further, in this embodiment, as shown in FIG. 8, the mold A and its mold clamping mechanism 40 are housed and arranged in the chamber 5 having an airtight structure, and the pressure reducing pump P ₁ and the pressure reducing valve V ₁ are provided. If the pipe L ₁ and the atmospheric pressure release pipe L ₀ equipped with the atmospheric pressure release valve V ₀ are connected to the chamber 5 and the pressure inside the chamber 5 is reduced by the pressure reducing pump P ₁ , the biodegradable resin is generated. Since the generated water vapor is forcibly discharged from the periphery of the mold A to the outside, there is an advantage that residual adhesion of water after vaporization and expansion to contribute to foaming can be prevented. However, in this case, the same effect can be obtained by ventilating the chamber 5 instead of depressurizing it. In this case, the chamber 5 may be configured so as to surround only the molding die A, and the mold clamping mechanism 40 may be disposed outside the chamber 5.

(4) Example of Manufacturing Method According to Claim 8 Prior to the description of the example of the manufacturing method according to claim 8, a manufacturing apparatus used in this example will be described with reference to FIG. Since the basic structure of the manufacturing apparatus is the same as that of the manufacturing apparatus shown in FIG. 1, the details thereof will be omitted here, and only different parts will be described.

That is, in the case of the manufacturing apparatus shown in FIG.
A pressurizing pipe L ₃ and a depressurizing open pipe L ₄ are connected to the chamber 5, and a depressurizing pipe L ₁ , a depressurizing valve V ₁ , and a depressurizing pump P provided in the manufacturing apparatus shown in FIG. ₁ has been eliminated. The pressurizing pipe L ₃ is connected to a compressor C via a pressurizing valve V ₃ for pressurizing the inside of the chamber 5.
On the other hand, the decompression open pipe L ₄ corresponds to the atmospheric pressure open pipe L ₀ in the manufacturing apparatus shown in FIG. 1, and is opened to the atmosphere via the decompression open valve V ₄ .

The manufacturing method of the present invention will be described using the manufacturing apparatus having the above-described structure. First, the mold A is clamped, and the inside of the chamber 5 serving as a pressure adjusting chamber is compressed by the compressor C. Under pressure,
As shown in (1), water and granules 10 of biodegradable resin are supplied into the hopper 11, and the screw 2 pushes the inside of the cylinder 1 forward. The granules 10 of the biodegradable resin are heated to a temperature around the softening point or the melting point due to the shearing force accompanying the rotation of the screw 2 and the heating from the inner wall of the cylinder 1 by the heater 13 while being pushed. It accumulates in a fluid state in the internal space of the cylinder 1 on the tip side.

At this time, since the internal space is in a heated and pressurized state, the water contained in the biodegradable resin granules 10 does not evaporate from the fluid biodegradable resin and enters it. It is in a trapped state. Then, the rotation of the screw 2 is stopped, and the piston 2 in the injection cylinder 22 is stopped.
3 is operated to advance the screw 2 as shown in FIG. 10 (a), and the fluid biodegradable resin is injected into the molding space R in the molding die A at once from the narrowing opening 1a.

Since the inside of the chamber 5 is under pressure, the cavity 31 and the core 41 of the mold A communicating with the inside of the chamber 5 through the porous portion of the mold A are also under pressure. The pressure of the biodegradable resin injected from the narrowed opening 1a is set to a pressure higher than the water vapor pressure at 170 ° C., for example, about 10 kgf / cm ^2, so that the biodegradable resin is contained in the biodegradable resin. The water is pushed out into the molding space R while being trapped.

Then, after the biodegradable resin is filled in the molding space R, the decompression release valve V ₄ is opened at a stroke to open the chamber 5 to the atmosphere as shown in FIG. Since the resin is rapidly exposed to the atmospheric pressure from the heated and pressurized state, the water trapped therein is instantaneously evaporated and foamed. The expanding force of the water vapor acts in the biodegradable resin, but since the outermost portion of the biodegradable resin is in contact with the forming die A, the shape of the cavity 31 and the core 41 is restricted, while the water vapor is porous in the forming die A. The biodegradable resin is diffused through the portion into the chamber 5 and bubbles 100 (foam cells) are formed inside the biodegradable resin. Thus, for example, as shown in FIG. Foam B is obtained.

On the other hand, as shown in FIG. 10 (c), the biodegradable resin which became fluid again during the backward movement while rotating the screw 2 starts to accumulate in the internal space of the cylinder 1 on the tip side of the screw 2. Prepare for the next shot. During this time, in the molding space R in the molding die A, since the cooling and solidification of the biodegradable resin foam B after molding is completed, the molding die A is opened and the biodegradable resin foam B is taken out and again. Close the mold and perform the following operations.

In the above method, the molding space R formed by the cavity 31 and the core 41 is kept in a pressurized state until the fluid biodegradable resin is pushed into the molding space R through the narrowed opening 1a. Since the foaming does not occur, the interior of the molding space R is suddenly depressurized and foaming occurs, so that it is possible to obtain a biodegradable resin foam B that is a mold and is homogeneous, and is a high-quality cushioning material. Can be used as

That is, in the above method, the timing of foaming of the biodegradable resin extruded from the narrowed opening 1a is adjusted by depressurizing the inside of the chamber 5 from the pressurized state. In other words, the timing of foaming is not limited to after the biodegradable resin is completely filled in the molding space R, and the pressure may be reduced during the pressing into the molding space R. This timing may be appropriately set depending on, for example, the extrusion rate from the narrowed opening 1a and the heating temperature of the biodegradable resin.

When decompressing the inside of the chamber 5, the pressure may be atmospheric pressure, lower than atmospheric pressure, or higher than atmospheric pressure. However, if the pressure is reduced to a pressure lower than atmospheric pressure, a large pressure difference is obtained. Since the cells become large and high foaming is possible, and steam is discharged to the outside of the chamber 5, there is an advantage that residual adhesion of water after vaporization and expansion to contribute to foaming is prevented.

In the above, as an apparatus for carrying out the present invention, for example, as shown in FIG. 11, the chamber 5 is divided into a movable side dividing portion 51 and a fixed side dividing portion 52, and the movable side dividing portion 51 is movable. It may be configured so as to be movable integrally with the side mold 4. With this configuration, since the molding die A and the chamber 5 can be opened and closed at the same time, the biodegradable resin foam B can be taken out easily. is there.

(5) Embodiment of Manufacturing Method According to Claim 9 Prior to the description of the embodiment of the manufacturing method according to Claim 9, a manufacturing apparatus used in this embodiment will be described with reference to FIG. Since the basic structure of the manufacturing apparatus is the same as that of the manufacturing apparatus shown in FIG. 1, the details thereof will be omitted here, and only different parts will be described.

That is, in the case of the manufacturing apparatus shown in FIG. 12, the substantially triangular pyramidal cavity 31 in the manufacturing apparatus shown in FIG. 1 is made into a square shape as an example, and in the manufacturing apparatus shown in FIG. As an example, the core 41 having a substantially triangular pyramid shape that is smaller than the wall thickness is formed into a shape having a small square convex portion on one surface of a square shape. The diameter of the constriction opening 1a is the same as the conventional general injection in order to inject the fluid material in the heated and pressurized state from the constriction opening 1a into the molding space R formed by the cavity 31 and the core 41 in the atomized state. It is necessary to make the diameter smaller than the nozzle of the molding machine. That is, the diameter of the nozzle of the conventional general injection molding machine is set to, for example, 2 to 5 mm, but in this embodiment, for example, the diameter of the narrowing opening 1a is set to a small diameter of about 1 mm.

The manufacturing method of the present invention according to claim 9 will be described using the manufacturing apparatus having the above-described structure. First, the mold A is clamped, and water and biodegradable resin are stored in the hopper 11. The granules 10 are supplied, and the screw 2 pushes the inside of the cylinder 1 forward as shown in FIG. The granules 10 of the biodegradable resin are heated to a temperature around the softening point or the melting point due to the shearing force accompanying the rotation of the screw 2 and the heating from the inner wall of the cylinder 1 by the heater 13 while being pushed. It accumulates in the internal space of the cylinder 1 on the tip side as a fluid material. At this time, the internal space is heated and pressurized, and the water contained in the granules 10 of the biodegradable resin is trapped in the fluid without being evaporated from the fluid.

Subsequently, as shown in FIG. 13B, the rotation of the screw 2 is stopped and the piston 23 in the injection cylinder 22 is stopped.
Is operated to move the screw 2 forward to inject the fluid material from the constriction opening 1a into the molding space R formed by the cavity 31 and the core 41 in the molding die A in an atomized state.

Here, in order to inject in the atomized state, the diameter of the narrowing opening 1a is made smaller than that of the conventional one as described above, and the injection speed of the fluid material by the screw 2 and the fluidity The pressure difference before and after extrusion of the product may be adjusted appropriately. Since the diameter of the narrowed opening 1a required for the atomized state varies depending on the extrusion speed of the fluid material, it is not necessarily limited to about 1 mm as described above.

On the other hand, since the outside of the molding die A is open to the atmosphere, the molding space R is also at atmospheric pressure via the porous portion of the breathable molding die A. Therefore, since the biodegradable resin injected at once in the molding space R in the atomized state is rapidly exposed to the atmospheric pressure from the heating and pressurizing state,
The water trapped in this momentarily evaporates and foams. The expanding force of the water vapor acts in the biodegradable resin, but the outermost portion thereof is in contact with the inner walls of the cavity 31 and the core 41 of the mold A and is regulated. Then, the water vapor is diffused to the outside through the porous portion of the mold A. On the other hand, foaming is performed for each particle inside the biodegradable resin to form air bubbles 100 (foaming cells), and these particles are entangled and fused together to form a whole biodegradable resin foam. Body B is obtained.

Next, as shown in FIG. 13 (c), when the screw 2 is rotated and retracted, the fluidized biodegradable resin begins to collect in the internal space of the cylinder 1 on the tip side of the screw 2 again. , Prepare for the next shot. During this time, in the molding space R in the molding die A, since the cooling and solidification of the biodegradable resin foam B after molding is completed, the molding die A is opened and the biodegradable resin foam B is taken out and again. Close the mold and perform the following operations.

In the above method, since the fluid biodegradable resin is injected from the constriction opening 1a into the molding space R under the atmospheric pressure in the atomized state, the biodegradable resin in the atomized state becomes the cavity 31. Particles forming the biodegradable resin in the atomized state are each foamed and collected while being filled in every corner of the molding space R formed by the core 41 and the core 41. Therefore, since the foaming is completed with the biodegradable resin entering every corner of the mold A, even if the mold A has a complicated shape, the foam cells are accumulated in the position floating from the inner surface of the mold and It is possible to mitigate or avoid the problem that the biodegradable resin is forced to be pressed and crushed by pressing, and therefore it is possible to suppress the crushing of the foam cells that have once foamed, so that the biodegradable resin having a desired shape and uniform. Foam B can be obtained, and as a result, sufficient cushioning performance can be obtained.

In the present embodiment, a ventilation atmosphere may be provided outside the molding die A. In this case, since water vapor is forcibly released to the outside of the molding die A, after vaporization and expansion to contribute to foaming. There is an advantage that residual adhesion of moisture is prevented.

The mold A may be placed inside the chamber 5 to reduce the atmosphere outside the mold A below atmospheric pressure. In this case, a large pressure difference can be obtained. In addition, the forced release action of water vapor is further increased, and dew condensation on the molding die A is suppressed.

Further, in this embodiment, it is possible to provide the nozzle 12 for the narrowed opening 1a. In this case, the number of the nozzle 12 is not limited to one, and a plurality of nozzles 12 are provided as shown in FIG. 14, for example. Or, depending on the case,
As shown in FIG. 5, a shower unit 15 having a large number of fine injection holes 14 may be provided at the tip of the cylinder 1. Although not shown, when the biodegradable resin is introduced into the mold A through the runner and the gate, the diameter of the runner and the gate may be reduced so that the biodegradable resin is in an atomized state. It may be introduced into the molding die A.

Further, in this embodiment, as shown in FIG. 16, the chamber 5 divided into a plurality of airtight decompression chambers 53, 54, 55 is provided so as to surround the mold A, and the decompression corresponding to each chamber is provided. Provide each with an open pipe L ₄ ,
The filling state may be adjusted so that the biodegradable resin in the atomized state is efficiently and sequentially filled from the back of the molding space R by changing the degree of decompression by each decompression open pipe L _4. . In this case, the chamber 5 is configured so that it can be opened and closed at the same time as the molding die A, for example.

(6) Example of Manufacturing Method According to Claim 12 Prior to the description of the example of the manufacturing method according to claim 12, the manufacturing apparatus used in this example will be briefly described. That is, the manufacturing apparatus shown in FIG. 17 is the same as the manufacturing apparatus shown in FIG. 1 described above, except that the chamber 5 provided in the manufacturing apparatus shown in FIG. 1 is omitted. ing.

Explaining the manufacturing method of the present invention according to claim 12 by using the manufacturing apparatus having the above-mentioned structure, first, the molding die A is clamped, and as shown in FIG. A granular body 10 of biodegradable resin containing a water-repellent substance and substantial water is supplied, and the screw 2 pushes the inside of the cylinder 1 forward. Granules of biodegradable resin 1
0 is fluidized by being heated to a temperature around the softening point or melting point, for example 170 ° C., by the shearing force accompanying the rotation of the screw 2 and the heating from the inner wall of the cylinder 1 by the heater 13 while being fed. The substance accumulates in the internal space of the cylinder 1 on the tip side of the screw 2.

At this time, the internal space was heated and pressurized, and the water contained in the granules 10 of the biodegradable resin was trapped in the fluidized biodegradable resin without being evaporated. It is in a state. Then, the rotation of the screw 2 is stopped, the piston 23 in the injection cylinder 22 is operated, and the screw 2 is advanced as shown in FIG.
A fluid biodegradable resin is injected into the molding space R in the molding die A all at once through the narrowed opening 1a.

As a result, the biodegradable resin is rapidly exposed to the atmospheric pressure from the heated and pressurized state, and the water trapped therein is instantaneously evaporated and foamed. On the other hand, since the water-repellent substance has a boiling point higher than that of water, most of it remains as a film on the surface of the foamed cell in the biodegradable resin. The expanding force of the water vapor acts in the biodegradable resin, but the outermost part of the force is the cavity 3 in the mold A.
1 is in contact with the inner walls of the core 41 and is regulated. Thus, as shown in FIG. 19, for example, a biodegradable resin foam B obtained by integrally molding the whole is obtained. After that, FIG.
As shown in (b), the screw 2 is retracted while being rotated, whereby the biodegradable resin that has become fluid again begins to accumulate in the internal space of the cylinder 1 on the tip side of the screw 2 and prepares for the next injection. During this time, in the molding space R in the molding die A, the cooling and solidification of the biodegradable resin foam B after molding is completed, so the molding die A is opened to take out the biodegradable resin foam B, and the mold is re-molded. Tighten and perform the following operation.

In the above method, since the water-repellent substance covers each film of the foamed cells of the biodegradable resin molded body, even if moisture adheres to the molded body, it is easy to remove and dry the moisture. Become. Furthermore, since a natural fatty acid polymer is used as the water-repellent substance, this is also biodegradable, and therefore the whole constituent components of the biodegradable resin foam B are biodegradable, which is preferable.

Here, in the present invention, as shown in FIG. 20, the molding die A is arranged in the chamber 5 having an airtight structure which can be divided into the movable side divided portion 51 and the fixed side divided portion 52, and the biodegradable resin is constricted. Before or after pushing out from 1a, the pressure reducing valve V ₁ may be opened at a predetermined timing, for example, 1 second later, and the pressure may be reduced by the pressure reducing pump P ₁ through the pressure reducing pipe L ₁ . As shown in the figure, the mold A may be arranged in the ventilation duct D and forcedly ventilated by the suction fan f. In this way, the water is forcibly removed from the mold A, so that the residual moisture The removal and drying work is unnecessary. In FIG. 20, reference numeral L ₀ indicates an atmospheric pressure release pipe, and V ₀ indicates an atmospheric pressure release valve.

In the above, according to the present invention, the biodegradable resin granules 10, the water and the water repellent substance may be put into the separate hopper 11, or alternatively, the cylinder 1 may be provided with a separate inlet. Water or a water-repellent substance may be directly injected from here. Furthermore, in the present invention, one molded body is not obtained by the molding die A in a batch system, but may be obtained by continuously extruding a die to obtain a continuous rod-shaped body having an appropriate cross-sectional shape that matches the shape of the die. Good. In this case, the thick continuous rod-shaped body may be obtained by subsequently joining the plurality of them or by twisting the plurality of extruded foams and fusing them together.

Further, according to the present invention, instead of arranging the molding die A in front of the constriction opening 1, a breathable cylindrical body is connected, and a plurality of molded bodies extruded from this and molded into a cylindrical shape are prepared. Thus, for example, the present invention can be applied to the case where the adhesives are joined in parallel to form a single molded body.

Further, the present invention is not limited to the extrusion foaming method using an injection molding machine or the like, but a breathable mold A is placed in a closed heating container to biodegrade a predetermined amount of a water-repellent substance. The resin may be put in the mold A, heated steam may be supplied into the heating container, and then the pressure in the heating container may be reduced. Alternatively, a step of foaming the biodegradable resin You may make it separately perform the process of shape | molding using.

Next, various embodiments of the manufacturing apparatus of the present invention which is characterized by the pressure adjusting mechanism in the molding die A and other manufacturing methods of the present invention using this manufacturing apparatus will be described. (7) Embodiment of the manufacturing apparatus according to claim 17 The manufacturing apparatus according to the present invention described in claim 17 is shown in FIG. 21, and its basic configuration is the same as that of the manufacturing apparatus shown in FIG. So, I will omit the details,
In this embodiment, it is desirable that the diameter of the narrowed opening 1a or the diameter of the nozzle 12 when the nozzle 12 is provided in the narrowed opening 1a is about 6 mm. When the nozzle 12 is provided, the nozzle 12 provided with a shutoff valve is attached.
Is recommended.

The structure of the manufacturing apparatus of the present invention will be specifically described below, focusing on the points different from the manufacturing apparatus shown in FIG. First, a chamber 5 as a pressure adjusting chamber is provided at the tip of the injector S. In this example, the chamber 5 is
It is configured by using a mold in a so-called injection molding machine, and a fixed mold 3 having a cavity 31 communicating with the narrowed opening 1a and a movable mold 4 having a core 41 formed therein.
The fixed-side mold 3 and the movable-side mold 4 are mounted on the fixed-side die plate 40A and the movable-side die plate 40B in the mold clamping mechanism 40 of the injection molding machine, respectively. The cavity 31 has, for example, a rectangular shape, and forms a molding space R together with the core 41 having the same rectangular shape. In the molding space R, a breathable molding die A is arranged. The molding space R of the molding die A of this embodiment has, for example, a rectangular shape having a L-shaped cross section as a corner angle, and its position is fixed by a positioning rod 30 arranged in the chamber 5. The shape of the molding space R of the molding die A is not particularly limited, and it is also possible to prepare the molding dies A having various shapes in advance and appropriately replace and use them.
Further, in this embodiment, the chamber 5 and the mold clamping mechanism 40 are arranged so as to be open to the atmosphere.

A decompression pipe L ₁ is connected to the chamber 5, and a decompression valve V ₁ is provided in the middle thereof.
A decompression tank T ₁ for rapid decompression is connected through the decompression valve V _1, and a decompression pump P ₁ is further connected to the decompression tank T ₁ . The inside of the decompression tank T ₁ is decompressed by a decompression pump P ₁ in advance to near a predetermined pressure, for example, under vacuum, and communicates with the inside of the chamber 5 when the decompression valve V ₁ is opened. . The decompression tank T ₁ needs to have a capacity sufficient to rapidly depressurize the interior of the chamber 5 when communicating with the interior of the chamber 5.

According to the above apparatus, the biodegradable resin foam B is formed, for example, as follows. First chamber 5
Is clamped by the mold clamping mechanism 40, and the inside of the chamber is sealed, for example, at atmospheric pressure. Then, the biodegradable resin in a fluidized state according to the above-described manufacturing method of the present invention is injected all at once into the molding die A through the narrowing opening 1a. After injection, pressure reducing valve V
_{When 1} is opened to connect the decompression tank T ₁ to the chamber 5 and the inside of the chamber 5 is rapidly decompressed to, for example, about 750 mmHg by a gauge pressure, the water trapped in the biodegradable resin until now evaporates instantaneously. As a result, the water vapor is foamed and the water vapor is exhausted from the vent holes of the mold A into the decompression tank T ₁ all at once. At this time, the expanding force of the water vapor acts in the biodegradable resin, but since the outermost portion thereof is in contact with the cavity 31 and the inner wall of the core 41 in the molding die A, the foamed portion forms a molding space formed by these. The biodegradable resin foam B having a predetermined shape is formed by being restricted to the shape of R.

Then, the pressure reducing valve V ₁ was closed to cut off the communication between the pressure reducing tank T ₁ and the chamber 5, and then the screw 2 was moved backward while being rotated. It begins to accumulate in the internal space of the cylinder 1 on the tip side of the screw 2 and prepares for the next injection. At the same time, the decompression pump P ₁ is operated to decompress the inside of the decompression tank T ₁ to the initial pressure again. During this time, since the cooling and solidification of the biodegradable resin foam B after molding is completed in the molding die A, the movable side mold 4 is fixed to the fixed side mold 3.
The biodegradable resin foam B is taken out by moving the mold away from the mold, the mold is clamped again, and the next operation is performed.

(8) Embodiment of Manufacturing Apparatus According to Claim 18 The manufacturing apparatus of the present invention according to claim 18 is shown in FIG. In this embodiment, the exhaust pipe L ₂ is connected to a portion between the pressure reducing valve V ₁ and the chamber 5 in the vacuum pipe L ₁ connected to the pressure adjusting chamber serving chamber 5, an exhaust pipe L ₂ An exhaust valve V ₂ is provided in the middle of, and the outlet of the exhaust pipe L ₂ is opened under atmospheric pressure, for example. Then, as shown in the time chart of FIG. 23, after the biodegradable resin is injected into the molding die A by the injection machine S, the exhaust valve V ₂ is opened to open the chamber 5 to, for example, the atmospheric pressure, and after injection. The exhaust valve V ₂ is closed and the depressurization valve V ₁ is opened so that the depressurization tank T ₁ is communicated with the chamber 5 to bring about a rapid depressurization state, and the manufacturing apparatus according to claim 16 is implemented. The configuration is similar to the example. Here, the opening timing of the exhaust valve V ₂ may be any time between the start of the injection of the biodegradable resin and the end of the injection, and it is not uniquely determined. Specifically, the shape of the mold A, the size of the chamber 5,
It is determined by comprehensively considering various conditions such as the degree of pressurization in the cylinder 1 when the biodegradable resin is injected.

Although the outlet of the exhaust pipe L ₂ is opened under the atmospheric pressure, the present invention is not limited to this. For example, a decompression pump P ₁ or the like may be provided to forcefully exhaust the gas under reduced pressure. However, a ventilation atmosphere may be created under atmospheric pressure. Regarding the relaxation of the injection resistance, in the embodiment of the manufacturing apparatus according to claim 17, the operating mechanism 4 of the mold clamping mechanism 40 is used.
4, the fixed-side mold 3 and the movable-side mold 4 are brought into contact with and separated from each other at a timing at which the air can flow in and out at the time of injection, and the mold is closed at the same time when the injection of the biodegradable resin is completed. It is also possible to deal with this by opening the pressure reducing valve V ₁ subsequently. In this case, the operation of the operating mechanism 44 of the mold clamping mechanism 40 and the pressure reducing valve V ₁
A control and controller for interlocking with the opening and closing of is required. Further, in other embodiments to be described later, in which the pressurizing operation is performed and the exhaust valve V ₂ is not additionally provided, it is possible to deal with it in accordance with this.

(9) Embodiment of manufacturing apparatus according to claim 19 The manufacturing apparatus according to claim 19 of the present invention is shown in FIGS. First, in the embodiment shown in FIG. 24, a pressurizing pipe L ₃ is connected to a chamber 5 which is a pressure adjusting chamber, and a pressurizing valve V ₃ is provided in the middle of the pressurizing pipe L _3, and a compressor is provided via the pressurizing valve V _3. C is connected, and after the injection of the biodegradable resin into the mold A by the injection machine S is started or before, the pressurization valve V ₃ is opened to make the chamber 5 a pressurized state by the compressor C, and after injection. In addition to closing the pressurizing valve V ₃ to stop the pressurizing operation by the compressor C, opening the depressurizing valve V ₁ so that the depressurizing tank T ₁ is communicated with the inside of the chamber 5 so that the pressure is rapidly reduced. Has the same configuration as the embodiment of the manufacturing apparatus according to claim 16.

Here, the degree of pressurization in the chamber 5 may be a pressure higher than the saturated vapor pressure at the temperature at which the biodegradable resin is injected into the mold A through the narrowing opening 1a, for example, biodegradation. When the injection temperature of the resin is 170 ° C., it is about 10 kg / cm ² . When the compressor C is attached to the chamber 5 via the pressurizing valve V ₃ instead of the pressurizing tank T ₃ as in the embodiment described later, the pressurizing valve V ₃ remains open without being controlled. Alternatively, it is possible to omit the attachment of the pressurizing valve V ₃ and perform the same function. This also applies to other embodiments described below.

[0133] On the other hand, in the embodiment shown in FIG. 25, with the pressurizing pipe L ₃ in the pressure adjusting chamber serving chamber 5 is connected, the pressurizing valve V ₃ is provided in the middle, the pressurizing valve V ₃ The compressor C is connected via the
As shown in the time chart of No. 6, from the time when the injection of the biodegradable resin into the mold A by the injection machine S is started, the pressurizing valve V ₃ is opened and the chamber C is pressurized by the compressor C. The pressurizing operation by the compressor C is stopped by closing the pressurizing valve V ₃ , and the exhaust valve V ₂ is opened to open the inside of the chamber 5 to, for example, the atmospheric pressure, and after the injection, the exhaust valve V ₂ is closed. At the same time, the depressurizing valve V ₁ is opened so that the depressurizing tank T ₁ is communicated with the chamber 5 so that the depressurizing state is abruptly reduced, and the structure is the same as that of the embodiment of the manufacturing apparatus according to claim 18.

(10) Embodiment of Manufacturing Apparatus According to Claim 20 The manufacturing apparatus according to claim 20 of the present invention is shown in FIGS. First, in the embodiment shown in FIG. 27, a pressurizing pipe L ₃ is connected to the chamber 5 which is a pressure adjusting chamber, and a pressurizing valve V ₃ is provided in the middle thereof, and pressurizing is performed via this pressurizing valve V _3. A tank T ₃ is connected, and a compressor C is connected to the pressure tank T ₃ .
From the time point of injecting the biodegradable resin into the mold A by the injection machine S or before that, the pressurizing valve V ₃ is opened to communicate the pressurizing tank T ₃ with the chamber 5 to rapidly pressurize. After the injection, the pressurizing valve V ₃ is closed to cut off the communication of the pressurizing tank T ₃ , and the depressurizing valve V ₁ is opened so that the depressurizing tank T ₁ is communicated with the inside of the chamber 5 so that the pressure is rapidly reduced. In addition to the above, the configuration is the same as that of the embodiment of the manufacturing apparatus according to claim 17.

[0135] On the other hand, in the embodiment shown in FIG. 28, with the pressurizing pipe L ₃ in the pressure adjusting chamber serving chamber 5 is connected, the pressurizing valve V ₃ is provided in the middle, the pressurizing valve V ₃ The pressure tank T ₃ is connected via the pressure tank T _3, and the compressor C is connected to the pressure tank T ₃ . The pressurization tank T ₃ is communicated with the chamber 5 at a time point before or before the injection of the biodegradable resin into the mold A by the injection machine S to make a rapid pressurization state, and the pressurization valve V ₃ is in the middle of the injection. Is closed to block the communication of the pressure tank T ₃ , and the exhaust valve V ₂ is opened to open the inside of the chamber 5 to, for example, the atmospheric pressure, and after the injection, the exhaust valve V ₂ is closed and the pressure for depressurization is reduced. Open the valve V ₁ to open the decompression tank T ₁
Is connected to the inside of the chamber 5 so that the pressure is suddenly reduced.

(11) Embodiment of Manufacturing Apparatus According to Claim 21 The manufacturing apparatus according to claim 21 of the present invention is shown in FIG. In this embodiment, a decompression pipe L ₁ and a pressurization pipe L ₃ are respectively connected to a chamber 5 which is a pressure adjusting chamber in which a breathable mold A is arranged, and the decompression pipe L ₁ is decompressed for rapid decompression. The tank T ₁ is connected, and the compressor C is connected to the pressurizing pipe L ₃ . A depressurization valve V ₁ is provided in the middle of the depressurization pipe L ₁ , and an exhaust pipe L ₂ is connected between the depressurization valve V ₁ and the chamber 5, and the exhaust pipe L ₂ is connected to the exhaust pipe L ₂ . An exhaust valve V ₂ is provided on the way. The outlet side of the exhaust pipe L ₂ is opened under atmospheric pressure, for example. The pressurizing operation of the compressor C, the exhaust valve V ₂ and the depressurizing valve V ₁
A valve controller 8 for controlling the opening and closing of is provided. Further, reference numeral S denotes an injection machine for injecting a fluid biodegradable resin in a heated and pressurized state in which water is trapped in the mold A.

Further, in this embodiment, a pressurizing valve V ₃ is also provided in the middle of the pressurizing pipe L ₃ , and the pressurizing valve V ₃ is opened / closed in conjunction with the turning on / off of the compressor C. Has become. In this case, for example, the valve controller 8 may also control the opening / closing of the pressurizing valve V ₃ . However, since the pressurizing operation can be controlled by directly turning on / off the compressor C by the valve controller 8, the pressurizing valve V ₃ is not always necessary. Further, the pressurizing valve V ₃ may be always open without any particular control. Since many of the valves have a directional flow path, there is no directional valve particularly when the pressurizing valve V ₃ and the depressurizing valve V ₁ or the exhaust valve V ₂ are attached to the chamber 5 at the same time. It is necessary to consider whether to use a valve or to use a valve so that pressurization and depressurization are not diminished. This point is the same in the other examples.

The valve controller 8 is composed of, for example, a timer that operates on the basis of the start of injection of the biodegradable resin, and controls the opening and closing of each valve according to the time chart shown in FIG. 26, for example. For example, when the injection operation of the biodegradable resin into the mold A by the injection machine S is started by turning on the start button, the pressurizing valve V ₃ which has been already opened before that time is set by the timer. The interior of the chamber 5 is pressurized by the compressor C, which is continuously opened for a certain period of time and at the same time when the pressurizing valve V ₃ is opened, is turned on and the biodegradation injected into the molding die A is performed. The resin is maintained in a pressurized state through the ventilation holes of the mold A, and the moisture is surely trapped.

Next, before the injection operation is completed, the pressurizing valve V ₃ is closed and at the same time the compressor C is closed.
Is turned off to stop the pressurizing operation, and the exhaust valve V ₂ is opened for a fixed time. Therefore, the biodegradable resin that was being injected under pressure is released into the atmosphere from the middle, so that the injection resistance is alleviated and the mold A
The biodegradable resin spreads to every corner inside. The time when the pressurizing valve V ₃ is closed and the compressor C is turned off and the exhaust valve V ₂ is opened at the same time is not necessarily determined uniquely, but the shape of the mold A, the volume of the chamber 5, the pressurization and the exhaust. It is appropriately adjusted according to the degree of

After the injection is completed, the exhaust valve V ₂ is closed and at the same time the pressure reducing valve V ₁ is opened for a fixed time. Therefore, after the injection, the decompression tank T ₁ is connected to the chamber 5 to rapidly decompress the atmosphere of the molding space R in the molding die A, and the water trapped in the biodegradable resin evaporates at once and biodegrades. Resin foam B is formed. Then, after a certain period of time, the pressure reducing valve V ₁ is closed.

(12) Embodiment of Manufacturing Apparatus According to Claim 22 The manufacturing apparatus according to claim 22 of the present invention is shown in FIG. This embodiment has the same structure as the embodiment of the manufacturing apparatus according to claim 21 shown in FIG. 29 except that a pressurizing tank T ₃ is added between the pressurizing valve V ₃ and the compressor C.

(13) Embodiment of manufacturing apparatus according to claim 23 Although not shown, claim 21 shown in FIG. 29 or FIG.
Alternatively, in the embodiment described in 22, the valve controller 8 does not provide the compressor C, the pressurizing tank T ₃ and the pressurizing valve V ₃ and exhausts the injection of the biodegradable resin into the molding die A by the injector S. The control valve V ₂ is opened, and after the injection, the exhaust valve V ₂ is closed and the pressure reducing valve V ₁ is opened.

(14) Embodiment of manufacturing apparatus according to claim 24 Although not shown, claim 21 shown in FIG. 29 or FIG.
Alternatively, in the embodiment described in 22, the pressurizing valve V ₃ is provided by the valve controller 8 without providing the exhausting valve V ₂ and before or before the injection of the biodegradable resin into the molding die A by the injection machine S is started. Is opened, and after the injection, the pressurizing valve V ₃ is closed and the depressurizing valve V ₁ is opened.

(15) Other Embodiments of Manufacturing Apparatus As shown in FIG. 31, the molding die A and its die clamping mechanism 4 are used.
The chamber 5 may be provided so as to surround 0 as a whole. In this case, the side plate 35 of the chamber 5 on the injector S side may also be used as the die plate. Further, as shown in FIG. 32, a chamber 5 is provided so as to surround the molding die A, and the chamber 5 is divided into a movable side dividing portion 51 and a fixed side dividing portion 52, and the movable side dividing portion 51.
May be configured to be movable integrally with the movable mold 4. In this case, the biodegradable resin foam B having a complicated shape can be easily taken out by simultaneously opening and closing the mold A and the chamber 5. Further, as shown in FIG. 33, the chamber 5 is provided so as to surround the molding die A, the side plate 35A of the chamber 5 is fixed to the fixed side die plate 40A, and the side plate 35B on the opposite side of the chamber 5 is moved to the movable side die plate 40B. Alternatively, the mold clamping mechanism may be double-equipped.

In addition to this, a pressure gauge may be provided in the chamber 5 in order to appropriately detect whether or not the pressure state in the chamber 5 is appropriate. Further, a pressure sensor is provided in the chamber 5 in order to prevent excessive pressurization at the time of pressurizing the chamber 5, and a variable flow rate valve is used as the pressurizing valve V _{3 to} confirm that the pressure exceeds a certain value. When detected, the flow rate of the pressurizing valve V ₃ may be limited.

Further, in order to improve the productivity of the biodegradable resin foam B, a plurality of depressurization tanks T ₁ and a plurality of pressurization tanks T ₃ may be provided and used sequentially.
That is, since the pressure changes once the decompression tank T ₁ and the pressure tank T ₃ are communicated with the chamber 5, it is necessary to return the pressure to the initial state for the next production of the biodegradable resin foam B. However, the decompression pump P ₁ and the compressor C
Since it takes a certain time for the pressure to return to the initial state, the waiting time becomes long. Therefore, multiple decompression tanks T ₃
If you decide to use such alternately provided, the other vacuum tank T ₃ during use of the one of the pressure reducing tank T ₃ and the like
Since it is possible to perform an operation of returning the above items to the initial state, a waiting time is not required, and the manufacturing process of the biodegradable resin foam B can be rapidly and repeatedly performed.

(16) Examples of the production method according to claims 14 to 16 The production method according to claim 14 is the biodegradable resin foam B according to claim 2, and the production method according to claim 15 is The biodegradable resin foam B according to claim 3 corresponds to the biodegradable resin foam B according to claim 4, and the production method according to claim 16 corresponds to the biodegradable resin foam B according to claim 4, respectively. The method is characterized in that the biodegradable resin is composed of acetate, which is a biodegradable resin, and biodegradable resin having a melting point not higher than the softening point of the acetate.

Further, in the production method according to claim 15, the biodegradable resin having a melting point equal to or lower than the softening point of the acetate is composed of polycaprolactone or one containing the same, and the production method according to claim 16. Each of the methods is characterized by adding a polyhydric alcohol and its derivative to the biodegradable resin.

The details of these are already described in the above item (1) and therefore omitted here, except that they are used as the raw material for the biodegradable resin for foam.
Since it has the same structure as the manufacturing method of the present invention described above, its details are omitted here. And claims 14 to
In carrying out the manufacturing method described in 16, the above-described manufacturing apparatus of the present invention is used as an example.

The above description constitutes the biodegradable resin foam, the method for producing the same, and the apparatus for producing the same according to the present invention. Molding for the purpose of further improving the quality of the biodegradable resin foam B. The atmosphere of the space R can be instantly decompressed,
Moreover, it is also possible to adopt the embodiment of the manufacturing method and the manufacturing apparatus having the following configurations capable of reducing the pressure of a large volume.

That is, FIG. 34 shows an embodiment of the manufacturing apparatus, in which a molding die A is provided at the front end of the injection machine S. The molding die A is composed of a stationary mold 3 having a cavity 31 communicating with the narrowed opening 1a and a movable mold 4 having a core 41 formed therein.
The fixed mold 3 and the movable mold 4 are attached to the fixed die plate 40A and the movable die plate 40B in the opening / closing mechanism of the molding die A, respectively. The cavity 31 has a square shape, for example, and constitutes a molding space R of the molding die A together with the core 41. The fixed mold 3 has an injection port 81,
Communication hole 82 for releasing airtightness and O-ring 83 for maintaining airtightness
Is provided.

The molding space R of the molding die A is sealed when the fixed side mold 3 and the movable side mold 4 are clamped by the opening / closing mechanism of the molding mold A. The movable side mold 4 of the molding die A can sequentially take the open position O ₁ , the airtight chain position O ₂ , the airtight release position O ₃ , and the open position O ₁ by the opening / closing mechanism. This opening / closing mechanism includes, for example, tie bars 42 and 43 for guiding the fixed side die plate 40A and the movable side die plate 40B so that the fixed side die 3 and the movable side die 4 come into contact with and separate from each other, and the movable side die plate. It is composed of an operating mechanism 44 and the like for moving the movable mold 4 together with 40B. The mold A and the opening / closing mechanism are, for example, arranged in an open state under atmospheric pressure.

A manufacturing method using such a manufacturing apparatus will be described below. First, the molding die A is clamped by the opening / closing mechanism to seal the molding space R under atmospheric pressure, for example. Next, for example, water and biodegradable resin particles 10 are supplied into the hopper 11, and the screw 2 pushes the inside of the cylinder 1 forward. The particles 10 of the biodegradable resin are heated to a temperature around the softening point or the melting point due to the shearing force accompanying the rotation of the screw 2 and the heating from the inner wall of the cylinder 1 by the heater 13 while being pushed, and the tip of the screw 2 is pushed. In the inner space of the cylinder 1 on the side, it accumulates as a fluid material. At this time, the internal space is heated and pressurized,
The water contained in the granules 10 of the biodegradable resin is forcibly confined in the fluid substance without evaporating from the fluid substance.

Then, the rotation of the screw 2 is stopped and the piston 23 in the injection cylinder 22 is driven to drive the screw 2
Is advanced to inject the fluid material into the molding space R at once through the narrowed opening 1a through the injection port 81. After the injection, when the movable mold 4 of the molding die A is moved to the airtightly released position O ₃ by the opening / closing mechanism, the inside of the molding space R is rapidly depressurized to, for example, the atmospheric pressure via the communication hole 82, and biodegradation has been performed so far. Moisture trapped in the resin is instantaneously evaporated and foamed, and water vapor is discharged to the outside through the communication hole 82. At this time, the force of expansion of the water vapor acts in the biodegradable resin, but the outermost contour of the biodegradable resin is restricted by the molding space R defined by the cavity 31 and the core 41, so that the biodegradable resin having a predetermined shape is formed. Foam B is formed.

Next, when the screw 2 is retracted while rotating, the biodegradable resin that has become fluid again starts to accumulate in the internal space of the cylinder 1 on the tip side of the screw 2 in preparation for the next injection. During this time, since the cooling and solidification of the biodegradable resin foam B after molding is completed in the molding space R, the movable side mold 4 is moved to the open position O ₁ by the opening / closing mechanism to remove the biodegradable resin foam B. After taking out, the movable side mold 4 is returned to the airtight chain position O ₂ again, and the next molding operation is performed.

FIG. 35 shows another embodiment of the manufacturing apparatus. In this embodiment, in the manufacturing apparatus shown in FIG.
Is the same as the above, except that the heating means 9 for heating the molding die A is provided. The heating means 9 is, for example, a heater 91.
And is arranged outside the fixed mold 3. The reference numeral 92 indicates a heating power source.

A manufacturing method using such a manufacturing apparatus will be described below. First, the movable mold 4 of the molding die A is moved to the open position O ₁ by the opening / closing mechanism. In this state, the biodegradable resin is placed in the molding space R formed by the cavity 31 and the core 41. Then, the movable side mold 4 is moved to the hermetically closed chain position O ₂ by the opening / closing mechanism,
The molding space R is made airtight. In this state, the heating means 9
The mold A is heated by the above to bring the biodegradable resin into a fluid state. The molding space R is heated and pressurized, and the water contained in the biodegradable resin is forcibly confined therein without evaporating. Next, the movable side mold 4 of the molding die A is moved to the airtight release position O by the opening / closing mechanism.
_When it is moved to ₃ , the inside of the molding space R is rapidly depressurized to, for example, the atmospheric pressure via the communication hole 82, and the water trapped in the biodegradable resin is instantaneously evaporated, and the water at that time is evaporated. This biodegradable resin is foamed by the vaporizing and expanding force of and the water vapor is discharged to the outside through the communication hole 82, whereby the biodegradable resin foam B having a predetermined shape is formed.
When the biodegradable resin foam B in the molding space R has cooled and solidified, the movable side mold 4 is moved to the open position O ₁ by the opening / closing mechanism to take out the biodegradable resin foam B, and the molding similar to the above is performed again. Do the operation.

Further, such a manufacturing apparatus is not limited to the above embodiment, and various modifications can be made, including the configuration of the other manufacturing apparatus embodiments described in (15) above. And

Further, the following examples can be given as examples of another manufacturing method and manufacturing apparatus according to the same idea as the above-mentioned embodiment. That is, FIG. 36 shows an example of the manufacturing apparatus. In the figure, reference numeral 5 is a chamber, and this chamber 5 is configured by using a mold in a so-called injection molding machine, and a fixed mold m ₁ in which a cavity communicating with the narrowed opening 1a is formed. and is composed of a movable mold m ₂ Prefecture, stationary side mold m _1, the fixed die plate 40A and the movable die plate 40B in the mold clamping mechanism of each of the movable side mold m ₂ injection molding machine Be installed. The cavity has, for example, a rectangular shape, and forms a chamber inside the chamber 5, in which a breathable pressing mold N corresponding to the molding die 2 is arranged.

The air-permeable pressing die N has a large number of air-holes for allowing water vapor to pass therethrough similarly to the forming die A. For example, foamed metal or a filler capable of forming voids is added. It can be composed of a sintered product of a metal or ceramics sintered and formed, a wire net, a punching metal having a large number of holes, or the like. Also this pressing-type N is constituted by divided upper mold n ₁ and a lower die n ₂ Prefecture, these upper die n ₁ and the lower mold n ₂ each moving mechanism 60a and 6
With 0b, it is possible to move between the foaming position O ₄ and the pressing position O ₅ .

The chamber 5 is hermetically sealed when the fixed side mold m ₁ and the movable side mold m ₂ are clamped by the mold clamping mechanism of the mold M. The chamber 5 and its mold clamping mechanism are arranged, for example, in an open state under atmospheric pressure. The chamber 5 has a decompression pipe L
₁ is connected and the pressure reducing valve V ₁
Is provided, and the decompression pump P ₁ is further connected. If necessary, a pressure reducing tank for rapid pressure reduction may be connected between the pressure reducing valve V ₁ and the pressure reducing pump P ₁ .

Then, a manufacturing method using such a manufacturing apparatus will be described below. First, the pressure reducing valve V
_{With 1} closed to make the chamber 5 airtight and the upper mold n ₁ and the lower mold n _{2 of the} pressing mold N located at the foaming position O ₄ , the narrow opening 1a into the pressing mold N. Inject molten biodegradable resin. After the injection, the pressure reducing valve V
_{When 1} is opened and the inside of the chamber 5 is depressurized, the water trapped in the biodegradable resin up to now evaporates and foams, and the water vapor is released from the vent hole of the pressing mold N through the depressurizing valve V ₁ It is discharged to the outside via. At this time, the force of expansion of this water vapor acts in the biodegradable resin,
Since the outermost portion thereof is in contact with the pressing die N, the foamed portion is restricted to the shape at the foaming position O ₄ of the pressing die N. After the foaming, the moving mechanisms 60a and 60b promptly move the upper mold n ₁ and the lower mold n ₂ of the pressing mold to the pressing position O ₅ to reduce the molding space R and compress the molding space R from the initial foaming condition for molding. . Therefore, the cavities and voids generated in the initial foaming disappear due to compression, and a biodegradable resin foam B having excellent quality is obtained. When the molding space R is rapidly reduced after foaming, it is difficult to expect fusion of the mutual walls in the state where the solidification cooling is advanced, so that water vapor still exists in the molding space R and the mutual wall is still present. It is desirable to check the timing at which fusion bonding and the like can be expected by various trials, and to compress at a timing at which stronger strength is obtained.

Further, even if the manufacturing apparatus shown in FIGS. 34 and 35 is used, the configuration described in the description of the manufacturing apparatus and the manufacturing method shown in FIG. 36 can be added. That is, the movable die 4 of the molding die A is opened at the open position O ₁ , and the airtight closed chain position O
₂ , the airtight release position O ₃ , and the open position O ₁ are moved to these positions in this order, instead of the embodiment shown in FIG. 34, the open position O ₁ , the airtight chain position O ₂ , the airtight release position O ₃ , and the pressing force. It is also possible to move to the respective positions in the order of the position O ₅ and the open position O ₁ (note that in the illustrated embodiment, the airtight chain position O ₂ and the pressing position O ₂ are substantially the same position). Has become).

Therefore, immediately after foaming, the movable side mold 4 of the mold A is immediately moved to the pressing position O ₅ by the opening / closing mechanism to reduce the molding space R, and the biodegradable resin foam B is compressed from the initial foaming state. Then, it is molded. With such a structure, the movable mold 4 is opened by the opening / closing mechanism of the molding die A.
Is moved to the pressing position O ₅ , the molding space R is reduced, and the biodegradable resin foam B is compressed from the initial foaming state and molded, so that the cavities and voids generated in the initial foaming disappear and the quality is excellent. A biodegradable resin foam B is obtained. Further, the molding space R is moved to the airtightness releasing position O ₃ through the communication hole 82.
Since the inside is opened, for example, under atmospheric pressure, the inside of the molding space R can be instantly made into a reduced pressure atmosphere with a large volume, and no water adheres to the biodegradable resin foam B, and residual water is removed. The drying work is unnecessary.

Further, in the above embodiment, the movable side mold 4 of the molding die A is allowed to take the airtightness releasing position O ₃ , the pressing position O ₅ and the opening position O _1, and the movable side mold 4 is opened and closed by the molding die A opening / closing mechanism. It is also possible to sequentially move the mold 4 to the open position O ₁ , the airtight release position O ₃ , the pressing position O ₅ , and the open position O ₁ . That is, with such a configuration, the movable side mold 4 is moved to the airtightness releasing position O ₃ by the opening / closing mechanism of the forming die A, and at the airtightness releasing position O ₃ from the injection port 81 of the forming die A by the injection machine S. A fluid biodegradable resin in a heated and pressurized state in which water is trapped is injected into the molding space R. At this time, the communication space 82 is formed in the molding space R.
Since, for example, an atmospheric pressure atmosphere is established via the, the pressurized state is released, and the biodegradable resin foam B is formed by the vaporizing and expanding force of water at that time. Immediately after this foaming, the movable side mold 4 is quickly moved to the pressing position O ₅ by the opening / closing mechanism to reduce the molding space R, and the biodegradable resin foam B is compressed from the initial foaming state and molded. Thus, even if the biodegradable resin is directly injected into the molding space R at the airtightness releasing position O ₃ , the same operation and effect as the manufacturing apparatus having the above-described configuration can be obtained.

Further, if the above-mentioned structure is applied to the embodiment shown in FIG. 35 as well, immediately after foaming, when the movable mold 4 of the molding die A is moved to the pressing position O ₅ by the opening / closing mechanism, the molding space R is formed. A biodegradable resin foam B which is reduced in size and compressed from the initial foaming state to be molded is obtained. When the biodegradable resin foam B is cooled and solidified, the movable side mold 4 is moved to the open position O ₁ by the opening / closing mechanism to take out the biodegradable resin foam B, and the molding operation similar to the above is performed again. With such a configuration, the same operational effects as those of the manufacturing apparatus can be exhibited.

[0167]

The biodegradable resin foam, the method for producing the same, and the apparatus for producing the same according to the present invention have the above-described structure. The effect is exhibited.
The biodegradable resin foam B according to any one of claims 1 to 4, wherein the biodegradable resin is composed of acetate or one containing the same,
Furthermore, in the biodegradable resin foam B according to claim 2,
The biodegradable resin is composed of acetate, which is a biodegradable resin, and a biodegradable resin having a melting point not higher than the softening point of this acetate. As a result, the low melting point biodegradable resin having a melting point equal to or lower than the softening point of acetate does not solidify immediately, and functions as an adhesive to the main component biodegradable resin, acetate. Therefore, even if voids or voids are formed, the biodegradable resin foam B in which the mutual walls are bonded to each other as much as possible
Can be obtained. In particular, when polycaprolactone or one containing it is used as the low melting point biodegradable resin having a melting point equal to or lower than the softening point of acetate, the function as the adhesive is sufficiently exerted, and the biodegradable resin further contains a plasticizer. When a certain polyhydric alcohol and its derivative are added, the boiling point of water in the biodegradable resin increases,
The foam cells are dense and uniform.

In the method for producing a biodegradable resin foam according to claim 5, the biodegradable resin which has been heated to a fluid state is rapidly released from a heated and pressurized state, and a mold which is further breathable is used. It is configured to be extruded inward and molded into a predetermined shape. As a result, the boiling point of the water contained in the biodegradable resin rises due to pressurization, so that the water remains in the cylinder 1 as a liquid, and the water is momentarily released from the heated and pressurized state. Then, the biodegradable resin is foamed. Further, the water vapor generated at this time is not diffused to the outside because the molding die has air permeability, and does not adhere to the manufactured biodegradable resin foam B.

In the method for producing a biodegradable resin foam according to a sixth aspect of the present invention, the atmosphere in which the mold A is placed is a reduced pressure or ventilation atmosphere before or after the start of extrusion of the biodegradable resin. Take As a result, the moisture in the mold A is vaporized and expanded, and then the temperature is lowered to drift in a steam state, and the outside of the mold A or the biodegradable resin foam B is not touched to cause dew condensation or water droplets. Will be eliminated. Therefore, it becomes unnecessary to remove residual water and dry.

In the method for producing a biodegradable resin foam according to the seventh aspect, the nozzle 12 provided for the narrowed opening 1a is positioned on the inner side of the mold A in the starting state.
A configuration is adopted in which the biodegradable resin is extruded and retracted relative to the mold A. As a result, the biodegradable resin is sequentially filled from the back side of the molding die A, so that the difference between the timing of reaching the details and corners of the molding die A and the timing of foaming becomes small, or substantially. Lost. As a result, the foam cells spread to every detail and every corner of the mold A, and therefore, the collapse of the foam cells can be prevented as much as possible, so that the biodegradable resin foam B having a desired shape and uniform can be obtained. .

[0171] In the method for producing a biodegradable resin foam according to claim 8, while the biodegradable resin is being extruded into the molding die A, the atmosphere in the molding die A is kept under pressure and extruded. After the completion, the pressure will be reduced rapidly. As a result, the biodegradable resin is extruded into the mold A in a state where the water is trapped, and after depressurization, the water is instantaneously evaporated to foam the biodegradable resin. Therefore, since the biodegradable resin foams in a state where it reaches every corner of the mold A,
A biodegradable resin foam B having a desired shape and homogeneous is obtained.

The method for producing a biodegradable resin foam according to claim 9 has a structure in which the biodegradable resin is injected into the mold through the constriction opening 1a in an atomized state. As a result, the biodegradable resin in the atomized state spreads to every corner of the molding die A, and is rapidly released from the heating and pressurizing state, and the moisture trapped inside is expanded at an attempt to evaporate at once. Then, the evaporated water is released to the outside of the air-permeable mold A, while the atomized biodegradable resins are foamed and aggregated, and the foamed cells are homogeneous in a desired shape without being crushed. A biodegradable resin foam B is obtained.

The method for producing a biodegradable resin foam according to any one of claims 10 to 12, wherein the biodegradable resin raw material for the foam is water and acetate, or a biodegradable resin containing the same, hygroscopic fine particles. It is composed of a substance in which water is absorbed in a particulate substance, the biodegradable resin or moisture, the biodegradable resin and a water repellent substance. As a result, desired foaming can be expected, and if a hygroscopic fine particle substance that has absorbed water is added to the biodegradable resin in advance, the fine particles have compatibility with the biodegradable resin and dispersibility. Is higher than the direct addition of water, and the water in the fine particles can be foamed starting from the fine particles at the time of foaming, and as a result, a finely and uniformly foamed biodegradable resin foam B can be obtained. Further, as the water-repellent substance, a substance having a boiling point that does not completely evaporate when released from the heated and pressurized state, for example, a natural fatty acid polymer is used, and the water-repellent substance covers each membrane of the foamed cell. The biodegradable resin foam B has water repellency and can easily remove residual water and dry.

The method for producing a biodegradable resin foam according to a thirteenth aspect is configured such that all of the foamed biodegradable resin extruded into the molding die A is molded into an integral shape. As a result, the biodegradable resin foam B having a relatively large volume can be formed, and the biodegradable resin foam B having various shapes can be formed.

The method for producing a biodegradable resin foam according to claims 14 to 16 has the same effects as those described for the biodegradable resin foam B according to claims 1 to 4.

According to the apparatus for producing a biodegradable resin foam according to claim 17, the moisture existing in the heated and pressurized atmosphere is confined by the pouring machine S in the air-permeable mold A arranged in the pressure adjusting chamber. When the biodegradable resin composed of the fluidized acetate or the one containing the same is injected, and then the decompression tank T ₁ is connected to the pressure adjusting chamber, the biodegradable resin is rapidly released from the heated and pressurized state. As a result, the water trapped inside will expand and expand in an attempt to evaporate at once, and the pressure can be rapidly reduced by the decompression tank T _{1 at an} appropriate timing, so that the moisture is rapidly diffused to the outside of the breathable mold A. In addition, there is no risk of water remaining in the mold A. Therefore, in the mold A, a uniform biodegradable resin foam B made of the biodegradable resin having a shape corresponding to the mold A is formed, and residual water removal and drying operations are unnecessary.

According to the apparatus for producing a biodegradable resin foam according to the eighteenth aspect, when the pressure adjusting chamber is opened by the exhaust valve V _{2 while the} biodegradable resin is being injected by the injector S, the molding die A can be used. Is breathable, the injection resistance of the biodegradable resin is relaxed, and the injection can be performed easily. Therefore, upsizing of the injector S can be prevented.

According to the apparatus for producing a biodegradable resin foam according to claim 19, since the compressor C is connected to the pressure adjusting chamber, when the biodegradable resin is injected by the injection machine S, first, When the pressure adjusting chamber is kept under pressure by the compressor C, the biodegradable resin can be injected while the water is surely trapped. Next, when the pressure adjusting chamber is opened by the exhaust valve V ₂ , the injection resistance is increased. Since it is relaxed, the biodegradable resin can be easily spread to every corner of the mold A.

According to the biodegradable resin foam manufacturing apparatus of the twentieth aspect, since the pressure tank T ₃ is connected to the pressure adjusting chamber, the pressure is applied at an appropriate timing during the injection by the injection machine S. The adjusting chamber can be rapidly put into a pressurized state.

According to the apparatus for producing a biodegradable resin foam according to claim 21, the decompression valve V ₁ and the exhaust valve V.
_Since the valve controller 8 for controlling the opening / closing of ₂ and the pressurizing operation of the compressor C is provided, the pressure adjusting chamber is adjusted in accordance with the timing of injection of the acetate or the biodegradable resin containing the same by the injector S. Surely pressurize, exhaust,
It is possible to control each state of decompression.

According to the biodegradable resin foam manufacturing apparatus of the twenty- _{second aspect} , the valve controller 8 for controlling opening / closing of the pressure reducing valve V ₁ , the exhaust valve V ₂ , and the pressurizing valve V ₃ is provided. Therefore, the pressure adjusting chamber can be surely controlled to the pressurized, exhausted, and depressurized states in accordance with the timing of injection of the acetate or the biodegradable resin containing the same by the injector S.

According to the biodegradable resin foam manufacturing apparatus of the twenty- _{third aspect} , since the valve controller 8 for controlling the opening / closing of the pressure reducing valve V ₁ and the exhaust valve V ₂ is provided, the injector S is used. The pressure adjusting chamber can be reliably controlled to be in the exhaust or depressurized state at the timing of injecting the biodegradable resin made of acetate or a material containing the same.

According to the biodegradable resin foam manufacturing apparatus of the twenty-fourth aspect, since the valve controller 8 for controlling opening / closing of the pressure reducing valve V ₁ and the pressurizing valve V ₃ is provided, the injector S is used. It is possible to reliably control the pressure adjusting chamber to each state of pressurization and depressurization in accordance with the injection timing of the biodegradable resin made of acetate or a material containing the same.

According to the apparatus for producing a biodegradable resin foam according to the twenty-fifth aspect, the same effects as those described in the method for producing a biodegradable resin foam according to the seventh aspect can be obtained.

[Brief description of drawings]

FIG. 1 is a skeletal vertical cross-sectional side view showing an example of a manufacturing apparatus used for carrying out the method for manufacturing a biodegradable resin foam of the present invention.

FIG. 2 is an explanatory view showing the manufacturing method stepwise in the same manner.

FIG. 3 is a perspective view showing a biodegradable resin foam of the present invention.

FIG. 4 is a skeletal vertical cross-sectional side view showing another manufacturing apparatus used for carrying out the above manufacturing method.

FIG. 5 is a skeletal vertical sectional side view showing still another manufacturing apparatus of the same.

FIG. 6 is a skeletal vertical sectional side view showing an example of a manufacturing apparatus used for carrying out another manufacturing method of the present invention.

FIG. 7 is an explanatory view showing the manufacturing method stepwise in the same manner.

FIG. 8 is a skeletal vertical sectional side view showing another manufacturing apparatus used for carrying out the manufacturing method of the above.

FIG. 9 is a skeletal vertical sectional side view showing an example of a manufacturing apparatus used for carrying out still another manufacturing method of the present invention.

FIG. 10 is an explanatory view showing the manufacturing method stepwise in the same manner.

FIG. 11 is a skeletal vertical cross-sectional side view showing another manufacturing apparatus used for carrying out the above manufacturing method.

FIG. 12 is a skeletal vertical sectional side view showing an example of a manufacturing apparatus used for carrying out still another manufacturing method of the present invention.

FIG. 13 is an explanatory view showing the manufacturing method stepwise in the same manner.

FIG. 14 is a perspective view showing another embodiment of a nozzle provided for a narrowed opening.

FIG. 15 is a perspective view showing an embodiment in which a shower portion is provided at the tip of a cylinder.

FIG. 16 is a skeletal vertical sectional side view showing another manufacturing apparatus used for carrying out the manufacturing method of the same.

FIG. 17 is a skeletal longitudinal sectional side view showing an example of a manufacturing apparatus used for carrying out still another manufacturing method of the present invention.

FIG. 18 is an explanatory view showing the manufacturing method in a stepwise manner.

FIG. 19 is a perspective view showing another embodiment of the biodegradable resin foam of the present invention.

FIG. 20 is a skeletal vertical cross-sectional side view showing another manufacturing apparatus used for carrying out the above manufacturing method.

FIG. 21 is a skeletal vertical sectional side view showing an example of an apparatus for producing a biodegradable resin foam of the present invention.

FIG. 22 is a skeletal side view showing another embodiment of the above.

FIG. 23: Injection, exhaust, when using the above manufacturing apparatus,
It is a time chart which shows each timing of pressure reduction.

FIG. 24 is a skeleton side view showing still another embodiment of the above manufacturing apparatus.

FIG. 25 is a skeleton side view showing still another embodiment of the same manufacturing apparatus.

FIG. 26: Injection, pressurization, when using the above manufacturing apparatus,
It is a time chart which shows each timing of exhaust and pressure reduction.

FIG. 27 is a skeleton side view showing still another embodiment of the same manufacturing apparatus.

FIG. 28 is a skeleton side view showing still another embodiment of the same manufacturing apparatus.

FIG. 29 is a skeleton side view showing still another embodiment of the same manufacturing apparatus.

FIG. 30 is a skeleton side view showing still another embodiment of the same manufacturing apparatus.

FIG. 31 is a skeletal vertical cross-sectional side view showing still another embodiment of the same manufacturing apparatus.

FIG. 32 is a skeletal vertical sectional side view showing still another embodiment of the same manufacturing apparatus.

FIG. 33 is a skeletal vertical cross-sectional side view showing still another embodiment of the same manufacturing apparatus.

FIG. 34 is a skeletal vertical cross-sectional side view showing an embodiment of a manufacturing apparatus capable of instantly reducing the pressure of the atmosphere in the molding space and capable of reducing the pressure of a large volume.

FIG. 35 is a skeletal longitudinal sectional side view showing another embodiment of the same.

FIG. 36 is a skeletal longitudinal sectional side view showing still another embodiment of the same.

[Explanation of symbols]

1 Cylinder 1a Constriction Opening 2 Screw 3 Fixed Side Mold 4 Movable Side Mold 5 Chamber 6 Moving Stand 7 Braking Mechanism 8 Valve Controller 9 Heating Means 10 Biodegradable Resin Particles 11 Hopper 12 Nozzle 13 Heater 14 Injection Hole 15 Shower part 21 Hydraulic motor 22 Injection cylinder 23 Piston 30 Positioning rod 31 Cavity 32 Insertion hole 35 Side plate 35A Side plate 35B Side plate 40 Clamping mechanism 40A Fixed side die plate 40B Movable side die plate 41 Core 42 Tie bar 43 Tie bar 44 Operating mechanism 51 Movable side Dividing portion 52 Fixed side dividing portion 53 Decompression chamber 54 Decompression chamber 55 Decompression chamber 60 Moving mechanism 60a Moving mechanism 60b Moving mechanism 61 Guide rail 62 Wheel 63 Wheel 64 Frame plate portion 65 Hydraulic cylinder 66 Piston 71 Adjusting portion 81 Injection port 82 Communication hole 83 O-ring 91 Heater 92 Heating power supply 100 Air bubble A Mold B Biodegradable resin foam C Compressor D Ventilation duct f Suction fan L ₀ Atmospheric pressure release pipe L ₁ Decompression pipe L ₂ Exhaust pipe L ₃ Pressurizing pipe L ₄ Decompression open pipe M Mold m ₁ Fixed mold m ₂ Movable mold N Press mold n ₁ Upper mold n ₂ Lower mold O ₁ Open position O ₂ Airtight chain position O ₃ Airtight release position O ₄ Foaming position O ₅ Pressing position P ₁ Decompression pump R Molding space S Injector T ₁ Decompression tank T ₃ Pressurization tank V ₀ Atmospheric pressure release valve V ₁ Decompression valve V ₂ Exhaust valve V ₃ Pressurization valve V ₄ Decompression release valve

Claims (25)

[Claims] 1. A rapid release of a fluid biodegradable resin in which water present in a heated and pressurized atmosphere is trapped,
A biodegradable resin foam produced by utilizing the vaporizing and expanding force of water generated thereby, wherein the biodegradable resin is acetate or a resin containing the same. 2. The biodegradable resin comprises acetate, which is a biodegradable resin, and a biodegradable resin having a melting point equal to or lower than the softening point of the acetate. Biodegradable resin foam. 3. The biodegradable resin foam according to claim 2, wherein the biodegradable resin having a melting point not higher than the softening point of the acetate is polycaprolactone or a resin containing the same. 4. The biodegradable resin foam according to claim 1, wherein polyhydric alcohols and derivatives thereof are added to the biodegradable resin. 5. A raw material of biodegradable resin for foam comprising acetate or a material containing the same is charged into a cylinder having a narrowed opening at the front, and the biodegradable resin containing acetate or the material is supplied with the biodegradable resin. While heating the inside of the cylinder, the temperature rises to a fluid state while being pushed toward the inside of the cylinder, and the fluidized biodegradable resin is extruded from inside the cylinder into a breathable mold located in front of it. A method for producing a biodegradable resin foam, which is characterized by being rapidly released from a pressurized state, foamed, and then molded into a shape corresponding to the shape of the molding die. 6. When the fluidized biodegradable resin is extruded into a mold, the atmosphere in which the mold is placed is depressurized or ventilated before or after the start of extrusion. The method for producing a biodegradable resin foam according to claim 5, characterized in that 7. When the fluidized biodegradable resin is extruded into a molding die, a nozzle provided for the constriction opening is positioned at the inner side of the molding die in a starting state, The method for producing a biodegradable resin foam according to claim 5 or 6, wherein the nozzle is made to retreat relatively to the mold while extruding the biodegradable resin. 8. When extruding the fluidized biodegradable resin into a molding die, the atmosphere in the molding die is kept under pressure during extrusion, and the molding die is extruded after completion of extrusion. The method for producing a biodegradable resin foam according to claim 5 or 7, characterized in that the atmosphere therein is rapidly depressurized. 9. When the fluidized biodegradable resin is extruded into a molding die, the biodegradable resin is injected into the molding die from the narrowed opening in an atomized state. The method for producing a biodegradable resin foam according to claim 5, 6, 7 or 8. 10. The biodegradable resin raw material for a foam comprises water and acetate, or a biodegradable resin made of a material containing the water and acetate. Alternatively, the method for producing the biodegradable resin foam according to item 9. 11. The biodegradable resin raw material for a foam is a hygroscopic fine particle substance that absorbs water, and is further added to the biodegradable resin. A method for producing a biodegradable resin foam according to any one of 6, 6, 7, 8 and 9. 12. The biodegradable resin raw material for foam is composed of water and a water repellent substance of acetate or a biodegradable resin containing the same. A method for producing a biodegradable resin foam according to 6, 7, 8 or 9. 13. When the foamed biodegradable resin is molded into a shape corresponding to the mold shape of the molding die, all of the foamed biodegradable resin extruded into the molding die is removed. The method for producing a biodegradable resin foam according to claim 5, 6, 7, 8, 9, 10, 11 or 12, wherein the biodegradable resin foam is formed into an integral shape. 14. The biodegradable resin comprises acetate, which is a biodegradable resin, and biodegradable resin having a melting point not higher than the softening point of the acetate. The method for producing a biodegradable resin foam according to claim 7, 7, 8, 9, 10, 11, 12 or 13. 15. The method for producing a biodegradable resin foam according to claim 14, wherein the biodegradable resin having a melting point not higher than the softening point of the acetate is polycaprolactone or a resin containing the polycaprolactone. 16. A polyhydric alcohol and a derivative thereof are added to the biodegradable resin, according to claim 5, 6, 7, 8, 9, 10, 11, 12, 13, 1.
The method for producing a biodegradable resin foam according to 4 or 15. 17. A pressure adjusting chamber that can be opened and closed and closed, an air-permeable mold disposed in the pressure adjusting chamber, a decompression tank for rapid decompression connected to the pressure adjusting chamber, and a heating for the mold. Biodegradable resin foaming, characterized by comprising an injector for injecting a biodegradable resin consisting of fluid acetate or one containing it, in which water present in a pressurized atmosphere is trapped. Body manufacturing equipment. 18. The biodegradable resin foam manufacturing apparatus according to claim 17, wherein an exhaust valve is connected to the pressure adjusting chamber. 19. The apparatus for producing a biodegradable resin foam according to claim 17, wherein a compressor is connected to the pressure adjusting chamber. 20. The biodegradable resin foam manufacturing apparatus according to claim 17, wherein a pressure tank is connected to the pressure adjusting chamber. 21. A pressure adjusting chamber that can be opened and closed and closed, an air-permeable mold disposed in the pressure adjusting chamber, and a depressurizing tank for rapid depressurization connected to the pressure adjusting chamber via a depressurizing valve. An exhaust valve connected to the pressure adjusting chamber, a compressor connected to the pressure adjusting chamber, a valve controller that controls opening and closing of each valve, and an atmosphere in a heating and pressurizing state in the molding die. And an injection machine for injecting a biodegradable resin consisting of a fluid acetate in which existing water is trapped or one containing the fluid acetate,
The valve controller starts the pressurizing operation of the compressor at or before the start of the injection of the biodegradable resin into the molding die by the injection machine, and stops the pressurizing operation of the compressor from the middle of the injection and for the exhaust. An apparatus for producing a biodegradable resin foam, characterized in that the valve is opened, and after injection, the exhaust valve is closed and the decompression valve is opened. 22. A pressure adjusting chamber that can be opened and closed and closed, a breathable mold disposed in the pressure adjusting chamber, and a depressurizing tank for rapid depressurization connected to the pressure adjusting chamber via a depressurizing valve. An exhaust valve connected to the pressure adjusting chamber, a pressurizing tank connected to the pressure adjusting chamber via a pressurizing valve, a valve controller for controlling opening / closing of each valve, and the molding die. And an injector for injecting a biodegradable resin consisting of a fluid acetate in which water existing in a heated and pressurized atmosphere is trapped or a material containing the same, wherein the valve controller is an injector. When the injection of the biodegradable resin into the mold is started by or before, the pressurizing valve is opened, the pressurizing valve is closed and the exhaust valve is opened during the injection, and the exhaust valve is closed after the injection. An apparatus for producing a biodegradable resin foam, which is configured to open a pressure reducing valve. 23. A pressure control chamber that can be opened and closed and closed, a breathable mold disposed in the pressure control chamber, and a decompression tank for rapid decompression connected to the pressure regulation chamber via a decompression valve. An exhaust valve connected to the pressure adjusting chamber, and a valve controller that controls opening and closing of each valve,
An injection machine for injecting a biodegradable resin consisting of a fluid acetate containing water contained in an atmosphere in a heated and pressurized state or a material containing the same into the mold, and the valve controller Open the exhaust valve during the injection of the biodegradable resin into the mold by the injection machine,
A device for producing a biodegradable resin foam, characterized in that after the injection, the exhaust valve is closed and the decompression valve is opened. 24. A pressure adjusting chamber that can be opened and closed and closed, a breathable mold disposed in the pressure adjusting chamber, and a depressurizing tank for rapid depressurization connected to the pressure adjusting chamber via a depressurizing valve. A pressure tank connected to the pressure adjusting chamber via a pressurizing valve, a valve controller for controlling the opening and closing of each valve, and water existing in the atmosphere under heating and pressurization in the molding die. An injector for injecting a biodegradable resin composed of a fluidized acetate or a material containing the same, wherein the valve controller starts the injection of the biodegradable resin into the mold by the injector. An apparatus for producing a biodegradable resin foam, characterized in that the pressurizing valve is opened at or before time, and after the injection, the pressurizing valve is closed and the depressurizing valve is opened. 25. The injector comprises a cylinder having a constriction opening in the front, and an acetic acid or a biodegradable resin material for a foam made of the material containing the acetic acid, which is charged into the cylinder, and is heated to flow. A pushing mechanism for pushing out a biodegradable resin composed of the acetic acid or a resin containing the same into the mold through the constriction opening, and relatively moving the constriction opening and the mold to form a fluid state. While extruding the biodegradable resin from the narrowing opening into the mold,
18. A moving mechanism for moving the narrowing opening backward relative to the molding die.
An apparatus for producing a biodegradable resin foam according to 9, 20, 21, 22, 23 or 24.