JP2001150495A - Biodegradable foamed molding, method for molding it and mold for molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the molding of the degradable foamed molding by an injection molding machine by using a natural polymer material by externally discharging a vapor or the like generated when molded through vent holes formed at the mold. SOLUTION: In the biodegradable foamed molding, the method for molding it and the mold for molding, the natural polymer material is plasticized, the vapor generated when the material is injected and foamed in the mold 1 is externally discharged from the vent holes 4 of the mold 1. Thus, the biodegradable foamed molding having good moldability and a small bulk specific gravity can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biodegradable foamed molded product, a method for molding the same, and a molding die. The present invention relates to a novel improvement for molding a biodegradable foamed molded article from a natural polymer material such as gluten and the like, and obtaining a molded article suitable for ecology and having a small specific gravity.

[0002]

2. Description of the Related Art Conventionally, an injection molding machine used in an injection molding method includes a well-known cylinder barrel without mentioning a document name, a driving device rotating in the cylinder barrel, and an injection nozzle at the tip of the cylinder barrel. And a mold, and a mold clamping device for fixing the mold. The injection material is a thermoplastic or thermosetting plastic material, and the specific gravity of the molded product is 0.2 g / cm ³ . It exceeded.

[0003] In the case of molding a biodegradable foamed molded product using the above-described injection molding machine for plastic materials, there are the following problems. In other words, when using a natural polymer material instead of a plastic material, and trying to obtain a biodegradable foamed molded product that foams using moisture in the material,
The natural polymer material injected into the mold has a reduced foaming rate with an increase in internal pressure due to foaming if the mold is closed or close to closed, and the injected material does not spread to every corner of the mold. A molded product having a desired shape could not be obtained. In addition, when the foamed steam condenses in the mold, the condensed water dissolves the foamed product, resulting in an uneven foaming state, which may impair the shape of the product. In addition, the injected material is cooled by contact with the inner surface of the mold, or by the water condensed in the mold, which lowers the fluidity of the material, and the injected material spreads to every corner of the mold. Was gone.

[0004] The present invention has been made to solve the above problems, and in particular, natural starch such as corn starch, rice, tapioca starch, potato starch, sweet potato starch, processed starch, soybean protein, corn protein, gluten and the like. It is an object of the present invention to provide a biodegradable foam molded article, which is suitable for ecology and obtains a molded article having a small specific gravity, and a molding method and a mold for the biodegradable foam molded article from a polymer material. .

[0005]

The method of molding a biodegradable foamed molded product according to the present invention comprises injection molding a plasticized material obtained by heating and plasticizing a natural polymer material into a temperature-controlled molding die. A method of discharging the steam generated at the time of foaming to the outside of the molding die from a plurality of air holes formed in the molding die, and wherein the natural polymer material is
A method using one or more of cornstarch, rice, tapioca starch material, soybean protein, corn protein, and gluten.
This is a method in which the temperature is controlled in the range of ° C to 210 ° C, and the amount of water contained in the natural polymer material is adjusted to 10% to 18%. Further, the biodegradable foamed molded article according to the present invention is molded by heating and plasticizing a natural polymer material and injecting and foaming it in a mold, and has a bulk specific gravity of 0.04 g / cm ³ or more.
The configuration is in the range of 0.20 g / cm ³ . The molding die according to the present invention forms a cavity, and comprises a pair of mold parts that can be freely opened and closed, wherein the molding die is configured to contact an injection nozzle with one of the mold parts. Each of the mold portions is provided with a ventilation hole communicating with the cavity.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a biodegradable foam molded product, a molding method and a molding die according to the present invention will be described below with reference to the drawings. In FIGS. 1 and 2, reference numeral 1 denotes a molding die. The molding die 1 is configured to be openable and closable with each other and to form a pair of first and second dies. It is formed of portions 1a and 1b. A heater 5 for controlling the temperature (setting the surface temperature of the cavity 2 in the range of 150 ° C. to 210 ° C.) is provided on the outer surface of each of the mold parts 1a and 1b, and one second mold part 1b is provided. The injection nozzle 14 of the injection molding machine 20 is configured to come into contact with the concave receiving surface 1c formed as described above. The injection nozzle 14 is configured to communicate with the cavity 2 via an injection port 1d formed in the second mold part 1b. A plurality of air holes 4 communicating with the cavity 2 are formed in each of the mold portions 1a and 1b, and each air hole 4 communicates with the mold outer surface 3 of each of the mold portions 1a and 1b. It is configured. The diameter of the vent hole 4 is such that the material foamed and solidified in the cavity 2 does not easily pass therethrough.
A range of mm is preferred.

In the injection molding machine 20, as shown in FIG. 1, a screw 10 rotated by a motor 11 controlled by a controller 9 is provided in a bore 8A of a cylinder barrel 8 to which the injection nozzle 14 is connected. Is rotatably provided, and a storage chamber 7 is formed at the distal end side of the lumen 8A. A heating heater 6 for heating the cylinder barrel 8 to control the temperature is provided on the outer periphery of the cylinder barrel 8, and a hopper 13 is provided on a rear end side of the cylinder barrel 8. .

Next, the operation will be described. First, prior to weighing, the controller 9 sets a weighing completion position A at which the screw 10 is retracted from the capacity of the molded product or the like. Further, the measurement is started after the temperatures of the plurality of cylinder heating heaters 6 are individually set. The motor 11 is started by a control signal 9a from the controller 9, and the screw 10
Is driven to rotate, and a natural polymer material, which is a granular or powder injection material, is provided to the screw 10 from the hopper 13. The natural polymer material is composed of one or more of corn starch, rice, tapioca starch, potato starch, sweet potato starch, processed starch, soybean protein, corn protein, gluten and the like.

The natural polymer material is melted by friction heat, shear heat, heat from the heater 6 and the like by the rotation of the screw 10 and is plasticized, and is accumulated in the accumulation chamber 7 of the cylinder barrel 8 as a plasticized material. You. The rotation of the screw 10 is stopped when the plasticized material in the molten state in the storage chamber 7 is stored to a predetermined amount.

In injecting the plasticized material in the above-described state, the injection nozzle 14 of the cylinder barrel 8 must be
Is communicated with the injection hole 1d of the receiving surface 1c of the second mold part 1b. The screw 10 is advanced to the nozzle side by a ball screw mechanism in order to inject the plasticized material in the molten state accumulated up to this predetermined amount, whereby the plasticized material in the molten state in the accumulation chamber 7 is injected from the injection nozzle 14 into the injection hole 1d. And is injected into the cavity 2.

The plasticized material in the molten state injected into the cavity 2 is released from the pressure inside the cylinder barrel 8 and foams with the moisture in the plasticized material to fill the cavity 2. At this time, internal pressure is generated in the cavity 2 due to volume expansion due to foaming of the plasticized material, but the pressure generated in the cavity 2 is radiated to the outside through the plurality of ventilation holes 4 communicating from the cavity 2 to the mold outer surface 3. . This plasticized material changes from a liquid having a high fluidity to a solid having a low fluidity when foaming is completed in the cavity 2 to obtain a biodegradable foamed molded product (not shown). At this time, no plasticizing material is discharged from the cavity 2 of the molding die 1 to the outside of the molding die 1 through the ventilation hole 4 communicating with the outer surface 3 of the molding die 1, or a very small amount of the plasticizing material exists. The retreat amount of the screw 10 at the time of the above-described injection is determined by the injection and the injection when the plasticized material injected into the cavity 2 just fills the cavity 2.
It is adjusted in advance so that the foaming is completed. Further, the amount of water contained in the natural polymer material is:
10% to 18% is preferable, and the bulk specific gravity of the biodegradable foamed molded product after molding is 0.04 g / cm ^{3 to} 0.20 g / c.
m ³ .

[0012]

The biodegradable foamed molded article according to the present invention, the molding method thereof and the molding die are constituted as described above, and the following effects can be obtained. That is,
A plurality of vents are provided in the molding die to allow the cavity to communicate with the outer surface of the die, and steam and the like generated during molding and foaming can be released to the outside through these vents, so that the internal pressure decreases, the foaming rate increases, and the plasticity increases. Material spreads to every corner of the mold,
A biodegradable foam molded article having good moldability can be obtained. Therefore, according to the biodegradable foamed molded product obtained by the present invention, a molded product which does not adversely affect the global environment even when discarded can be obtained because the natural polymer material is used as a raw material, and the thermoplastic or thermoformed product can be obtained. A molded product having a lower specific gravity than a curable plastic material can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a method for molding a biodegradable foamed molded product according to the present invention.

FIG. 2 is an enlarged sectional view showing a main part of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Molding die 1a, 1b Mold part 2 Cavity 4 Vent hole 14 Injection nozzle

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29K 105: 04 B29K 105: 04 C08L 3:00 C08L 3:00 F term (Reference) 4F074 AA03 BA34 CA26 DA02 DA34 4F202 AA01 AB02 AG20 CA11 CB01 CN18 CN22 CP01 4F206 AA01 AB02 AG20 JA04 JF01 JM04 JN05 JQ81 JW45

Claims (6)

[Claims] 1. A plasticized material obtained by heating and plasticizing a natural polymer material is injected into a temperature-controlled molding die (1) while being injected and foamed, and steam generated at the time of foaming is filled in the molding die.
From the plurality of ventilation holes (4) molded to (1) the molding die (1)
A method for molding a biodegradable foamed product, which is discharged to the outside. 2. The biodegradation according to claim 1, wherein the natural polymer material is one or more of corn starch, rice, tapioca starch material, soybean protein, corn protein, and gluten. Molding method for foamed molded articles. 3. The molding die (1) is heated at 150 ° C. to 210 ° C.
The method for molding a biodegradable foamed molded product according to claim 1, wherein the temperature is adjusted within the range of: 4. The method for molding a biodegradable foamed product according to claim 1, wherein the amount of water contained in the natural polymer material is 10% to 18%. 5. The natural polymer material is heated and plasticized, and is injection-foamed and molded in a mold, and has a bulk specific gravity of 0.5.
A biodegradable foamed molded product characterized by being in the range of 04 g / cm ^{3 to} 0.20 g / cm ³ . 6. A pair of mold parts (1a, 1b) forming a cavity (2) and being openable and closable.
In the molding die in which the injection nozzle (14) is brought into contact with (1b), the cavity (2) is provided in each of the die parts (1a, 1b).
A molding die, characterized in that a ventilation hole (4) communicating with the mold is provided.