JP4846861B2 - Extruder and biodegradable foamed material manufacturing method using the same - Google Patents

Description

  The present invention relates to an extruder and a method for producing a raw material for a biodegradable foamed product using the extruder.

  As a prior art related to the present invention, a puff raw material containing a starch raw material and water are supplied to an extruder, and heated and kneaded so that the starch raw material is gelatinized, and at the end of the extruder. A pellet forming step of forming pellets having an average particle diameter of 1.5 to 2.2 mm by extruding from the discharge holes of the mounted nozzle portion and cutting, and the pellets are heated and expanded, and an average particle diameter of 1. There is known a puff manufacturing method including an expansion step of obtaining a puff of 8 to 2.8 mm (see, for example, Patent Document 1).

  Further, as a further conventional technique related to the present invention, a biodegradable foamed molded article in which the surface of a foamed base material layer mainly composed of starch is coated with a hydrophobic film is known (for example, patent document). 2).

JP 2004-121067 A International Publication No. 02/022353 Pamphlet

As a food processing machine, an extruder capable of continuously performing various processes such as pulverization, mixing, heating, pressurization, sterilization, cooling, extrusion, and molding has been attracting attention.
The extruder is composed of a temperature-controlled cylinder and a pair of elongated screws that rotate parallel to each other in the cylinder and rotate in the same direction.
Each screw is configured by appropriately connecting a ball screw that conveys the material, a kneading screw that stirs and mixes the material, and a reverse screw that conveys the material in the reverse direction according to the purpose.
However, the total length of the screw is limited by the extruder, and it is necessary to combine the ball screw, the kneading screw, and the reverse screw so that the target process is continuously performed within the total length.

By the way, in recent years, there has been a strong demand for the reduction of garbage and the realization of a resource recycling society.
As a biodegradable container, one in which the surface of a foamed base material layer containing starch as a main raw material is coated with a hydrophobic biodegradable plastic film has been proposed.
In such a biodegradable container, the main raw material of the foam base material layer is mixed with additives such as pulp and polyvinyl alcohol for the purpose of cost reduction and strength maintenance after molding, in addition to starch.

However, in the raw material stage, the pulp is agglomerated, while starch and polyvinyl alcohol are powdered or granular and have different properties.
Therefore, there is a problem that even if starch, pulp, polyvinyl alcohol and water as main raw materials are supplied to the above-mentioned extruder together and stirred and mixed, the pulp does not disperse well uniformly.
Furthermore, if polyvinyl alcohol is dissolved by heating without the pulp being uniformly dispersed, the viscosity will be increased by the dissolved polyvinyl alcohol, while starch will become lumpy due to the effect of heat, making uniform stirring and mixing even more difficult. There was a problem of becoming.

  The present invention has been made in consideration of the above-described circumstances. An extruder that can be uniformly agitated, mixed and extruded even with materials having different properties, and a biodegradable foam molded product using the extruder. A method for producing a raw material is provided.

The present invention includes a temperature-controlled elongated cylinder and a pair of elongated screws that are parallel to each other in the cylinder and rotate in the same direction, and each screw feeds the material supplied to the cylinder from the proximal end side of the cylinder. Agitate pulp, powdered or granular polyvinyl alcohol and water using an extruder consisting of multiple ball screws that are transported to the tip and multiple kneading screws that stir and mix the material that has been transported. -Mixing to prepare a pulp dispersion, heating the prepared pulp dispersion to dissolve the polyvinyl alcohol in the dispersion, cooling the pulp dispersion in which the polyvinyl alcohol is dissolved, and cooling the pulp dispersion Is kneaded with starch to prepare a starch kneaded body, and the prepared starch kneaded body is heated to pre-gelatinize and pre-gelatinized starch kneaded body The temperature of the cylinder is gradually increased from room temperature to a range of 100 to 120 ° C. when preparing the pulp dispersion, and the temperature of the cylinder is increased when the pulp dispersion is heated to dissolve the polyvinyl alcohol. The temperature of the cylinder is gradually lowered from the range of 100 to 120 ° C. to the range of 35 to 50 ° C. when the pulp dispersion is cooled while maintaining the temperature in the range of 130 to 140 ° C. and 5 to 10 ° C. in the pulp dispersion. When adding starch, adding starch and preparing a starch kneaded body, the temperature of the cylinder is maintained in the range of 25 to 35 ° C., and when the starch kneaded body is heated and gelatinized, the temperature of the cylinder is 40 to 70. The present invention provides a method for producing a raw material for a biodegradable foamed molded product maintained in the range of ° C.
The present invention also includes a temperature-controlled elongated cylinder and a pair of elongated screws that are parallel to each other in the cylinder and rotate in the same direction, and each screw feeds the material supplied to the cylinder to the proximal end of the cylinder. Pulp, powdered or granular polyvinyl alcohol and water using an extruder in which a plurality of ball screws conveyed from the side to the tip side and a plurality of kneading screws for agitating and mixing the conveyed materials are alternately combined The pulp dispersion is prepared by stirring and mixing, the prepared pulp dispersion is heated to dissolve the polyvinyl alcohol in the dispersion, the pulp dispersion in which the polyvinyl alcohol is dissolved is cooled, and the cooled pulp A dispersion is kneaded with starch to prepare a starch kneaded body, and the prepared starch kneaded body is heated to be pregelatinized and pregelatinized starch. A step of obtaining a kneaded body, the temperature of the cylinder is gradually increased from room temperature to a range of 70 to 90 ° C. when preparing the pulp dispersion, and the pulp dispersion is heated to dissolve the polyvinyl alcohol. The temperature is maintained in the range of 130 to 140 ° C., and when the pulp dispersion is cooled, the temperature of the cylinder is maintained in the range of 35 to 50 ° C. and water at 5 to 10 ° C. is further added to the pulp dispersion. The temperature of the cylinder is maintained in the range of 25 to 35 ° C. when preparing the starch kneaded body, and the temperature of the cylinder is maintained in the range of 50 to 90 ° C. when the starch kneaded body is gelatinized by heating. Some provide a method for producing a raw material for a degradable foamed molded product.

  According to the extruder according to the present invention, each screw rotating in a temperature-controlled cylinder is composed of a plurality of ball screws that convey materials and a plurality of kneading screws that stir and mix materials alternately. Since it is comprised, even if it is a material from which a property differs, it can extrude by stirring and mixing appropriately, keeping at the temperature suitable for the material.

It is a perspective view of the extruder concerning Embodiment 1 of the present invention. It is explanatory drawing which shows a pair of screw inserted in the cylinder of the extruder shown by FIG. It is explanatory drawing which shows the ball screw and reverse screw which comprise the screw shown by FIG. It is a top view of the kneading screw which comprises the screw shown by FIG. FIG. 5 is a perspective view of the kneading screw shown in FIG. 4. It is explanatory drawing which shows the combination of a kneading screw. It is a perspective view which shows the kneading screw from which thickness differs. It is a FIG. 2 corresponding view of the extruder which concerns on Embodiment 2 of this invention. It is a FIG. 2 corresponding view of the extruder which concerns on Embodiment 3 of this invention. It is a FIG. 2 corresponding view of the extruder which concerns on Embodiment 4 of this invention. It is sectional drawing of the biodegradable foaming molding manufactured in the Example of this invention.

  The extruder according to the present invention includes a temperature-controlled elongated cylinder and a pair of elongated screws that are parallel to each other in the cylinder and rotate in the same direction, and each screw feeds the material supplied to the cylinder to the base of the cylinder. A plurality of ball screws conveyed from the end side to the front end side and a plurality of kneading screws for stirring and mixing the conveyed material are alternately combined.

In the extruder according to the present invention, each screw further includes a reverse screw that pushes back the material conveyed in the configuration from the distal end side to the proximal end side, and the reverse screw is adjacent to the distal end side of some kneading screws. It may be provided.
According to such a configuration, the material pushed back by the reverse screw stays in the arrangement portion of the kneading screw that stirs and mixes the material, and is filled in the cylinder. It is done efficiently. Further, since the material pushed back by the river screw is filled in the cylinder, heat exchange with the cylinder is also efficiently performed.

In the extruder according to the present invention, the cylinder may be formed by connecting a plurality of cylinder blocks, and the temperature of each cylinder block may be controlled independently.
According to such a configuration, the temperature of the cylinder can be controlled according to the process, and processes such as heating and cooling can be performed continuously.

  From another viewpoint, the present invention uses the above-described extruder according to the present invention to prepare a pulp dispersion by stirring and mixing pulp, powdered polyvinyl alcohol and water, and heating the prepared pulp dispersion. The polyvinyl alcohol in the dispersion is dissolved, the pulp dispersion in which the polyvinyl alcohol is dissolved is cooled, the cooled pulp dispersion is kneaded with starch to prepare a starch kneaded body, and the prepared starch kneaded body It also provides a method for producing a raw material for a biodegradable foam-molded product that is heated to gelatinize to obtain a gelatinized starch kneaded body.

  According to the manufacturing method of the present invention, by using the above-described extruder according to the present invention, pulp, polyvinyl alcohol, starch and water can be uniformly stirred and mixed, and extrusion molding can be performed. It becomes possible to mass-produce a kneaded starch kneaded body as a raw material of a product with a certain quality.

Here, the pulp means an aggregate of plant-derived fibers and is not particularly limited, and examples thereof include wood pulp (virgin pulp) and non-wood pulp.
Starch means starch or its derivatives, and is not particularly limited. For example, starch, potato, corn, tapioca, rice, wheat, sweet potato, etc. The obtained starch can be mentioned, The thing manufactured from the specific agricultural product may be used, and the thing manufactured from the several agricultural products may be mixed.

In addition, the above-mentioned starch derivatives refer to those obtained by modifying starch within a range that does not inhibit biodegradability, and examples thereof include pregelatinized starch, crosslinked starch, and modified starch.
Furthermore, a mixture obtained by mixing the above-mentioned unmodified starch and the above-mentioned starch derivative may be used.

  In the method for producing the raw material for the biodegradable foamed molding according to the present invention, the temperature of the cylinder is gradually increased from the normal temperature to the range of about 100 to 120 ° C. when the pulp dispersion is prepared, and the pulp dispersion is heated. When the polyvinyl alcohol is dissolved, the temperature of the cylinder is maintained in the range of about 130 to 140 ° C, and when the pulp dispersion is cooled, the temperature of the cylinder is about 100 to 120 ° C to about 35 to 50 ° C. The temperature of the cylinder is maintained in the range of about 25 to 35 ° C. when the starch kneaded body is prepared by introducing starch and the starch kneaded body is heated and pregelatinized. You may maintain in the range of about 40-70 degreeC.

  Further, the method for producing a raw material for the biodegradable foamed molded article according to the present invention comprises the step of gradually increasing the temperature of the cylinder from room temperature to a range of about 70 to 90 ° C. when preparing the pulp dispersion, The temperature of the cylinder is maintained in the range of about 130 to 140 ° C. when the polyvinyl alcohol is dissolved by heating and the temperature of the cylinder is maintained in the range of about 35 to 50 ° C. when the pulp dispersion is cooled. When the starch kneaded body is prepared, the temperature of the cylinder is maintained in the range of about 25 to 35 ° C., and when the starch kneaded body is heated to alpha, the temperature of the cylinder is set in the range of about 50 to 90 ° C. May be maintained.

These temperature conditions are cylinder temperature control conditions that have been found to uniformly agitate and mix pulp, polyvinyl alcohol, starch and water under more appropriate conditions and extrude.
However, such temperature control conditions vary depending on various factors such as material quality, distribution, and conveyance speed in the cylinder, so the above temperature conditions are not necessarily absolute. This is a standard for considering the temperature control conditions.

In the method for producing a raw material for the biodegradable foamed molded product according to the present invention, water at about 5 to 10 ° C. may be further added when the pulp dispersion is cooled.
According to such a manufacturing method, by adding cold water of about 5 to 10 ° C. to the pulp dispersion, the pulp dispersion heated in the previous step is efficiently cooled in order to dissolve the polyvinyl alcohol in the dispersion. it can. Thereby, it is possible to prevent the starch from being damaged under the influence of heat in the next step in which the pulp dispersion and starch are kneaded.

  Hereinafter, an extruder according to an embodiment of the present invention and a method for producing a raw material for a biodegradable foamed product using the same will be described with reference to the drawings. In addition, in the several embodiment demonstrated below, the same code | symbol is attached | subjected and demonstrated to the same member.

Embodiment 1
1 is a perspective view of an extruder according to Embodiment 1 of the present invention, FIG. 2 is an explanatory view showing a pair of screws inserted into the cylinder of the extruder shown in FIG. 1, and FIG. 3 is shown in FIG. FIG. 4 is a plan view of the kneading screw constituting the screw shown in FIG. 2, FIG. 5 is a perspective view of the kneading screw shown in FIG. 6 is an explanatory view showing a combination of kneading screws, and FIG. 7 is a perspective view showing kneading screws having different thicknesses.

  As shown in FIG. 1, an extruder 100 according to Embodiment 1 of the present invention includes a biaxial cylinder 1, a hopper 2 that supplies material into the cylinder 1, and a pair of screws that are inserted into the cylinder 1. 3 (see FIG. 2) and a drive unit 4 that rotates the pair of screws 3 in the axial direction.

The cylinder 1 is formed by connecting a plurality of cylinder blocks C1 to C11. A water jacket (not shown) is formed in each cylinder block C1 to C11 so as to surround the cylinder 1. Further, the cylinder blocks C4 to C8 and C11 are provided with a heater (not shown) in addition to the water jacket.
The cylinder blocks C1 to C3, C9, and C10 are temperature-controlled for each of the cylinder blocks C1 to C3, C9, and C10 by passing water whose temperature is controlled through the water jacket. In addition, the cylinder blocks C4 to C8 and C11 are provided for each of the cylinder blocks C4 to C8 and C11 by the action of the temperature-controlled water passing through the water jacket, the action of the attached heater, or both of them. Temperature controlled. Thereby, all the cylinder blocks C1 to C11 are temperature-controlled to a desired temperature for each cylinder block.
The biaxial cylinder 1 has an eight-shaped cross section obtained by fusing opposite portions of two cylinders arranged in parallel, and a pair of screws 3 (see FIG. 2) are provided in the cylinder 1. 1 is inserted coaxially.

In FIG. 1, the hopper 2 is drawn so as to straddle the cylinders C2 and C3. However, the hopper 2 is provided so that the material can be supplied to the cylinder C1.
Moreover, although not shown in figure, the same hopper is provided also in the upper part of the cylinder C10, and it is comprised so that the starch mentioned later can be supplied to the cylinder C10.

As shown in FIG. 2, the pair of screws 3 includes a first screw 3a and a second screw 3b, and the first and second screws 3a and 3b have basically the same configuration.
Depending on the purpose, the first and second screws 3a and 3b may be configured as shown in FIG. 3 (b) so that a desired process is continuously performed in the cylinder 1 having a predetermined length constituted by the cylinder blocks C1 to C11. ) To (d), a plurality of types of ball screws 5a, 5b, 5c having different helical pitches, a reverse screw 6 shown in FIG. 3 (e), and two types shown in FIGS. The kneading screws 7a and 7b and the thin kneading screw 8 shown in FIG. 7 are appropriately combined.

  The ball screws 5a, 5b, and 5c act so as to feed the raw material supplied into the cylinder 1 from the proximal end side to the distal end side (see FIG. 2) by rotating the shaft within the cylinder 1. The reverse screw 6 acts to push the raw material supplied into the cylinder 1 back from the distal end side to the proximal end side by rotating the shaft within the cylinder 1. The kneading screws 7a, 7b, and 8 act so as to pulverize, stir, and mix the raw material supplied into the cylinder 1 by rotating the shaft within the cylinder 1.

As shown in FIG. 3A, the ball screw 5 is formed with a hexagonal hole coaxially with the central axis thereof, which is not shown, but the same applies to the reverse screw 6.
Further, as shown in FIGS. 4A and 4B, hexagonal holes are formed on the two types of kneading screws 7a and 7b having a substantially elliptical appearance coaxially with the central axis. Yes. The kneading screws 7a and 7b have different hexagonal hole orientations.
The ball screws 5a, 5b, 5c, the reverse screw 6 and the kneading screws 7a, 7b, 8 have a positional relationship with each other by passing a core rod (not shown) having a hexagonal cross section through the holes. It is determined and becomes the long and thin integrated screws 3a and 3b.

As shown in FIGS. 3B to 3D, the plurality of types of ball screws 5a, 5b and 5c having different helical pitches have the same length. That is, the ball screws 5a, 5b, and 5c have the same length 1D on the basis of the maximum diameter 1D of the ball screw 5 shown in FIG.
The reverse screw 6 shown in FIG. 3 (e) has a length 1 / 2D that is half of the ball screws 5a, 5b, and 5c.

  3 (b) to 3 (d), “4/4”, “3/4”, and “2/4” are written next to the ball screws 5a, 5b, and 5c, respectively. The pitch represents the pitch. For example, at the spiral pitch “4/4”, the spiral advances 1D in length by one rotation. For this reason, as the spiral pitch becomes “4/4”, “3/4”, “2/4”, the transport speed becomes slower. As shown in FIG. 3E, the spiral pitch of the reverse screw 6 is “4/4”.

The kneading screws 7a and 7b shown in FIGS. 5A and 5B are of a type called KD and have a thickness 1 / 4D that is 1/4 that of the ball screws 5a, 5b, and 5c. That is, the KD type kneading screws 7a and 7b have the same length 1D as the ball screws 5a, 5b, and 5c by being overlapped.
Furthermore, the kneading screw 8 shown in FIG. 7 is a thin type called TKD, and has a thickness 1 / 8D that is half that of the KD type kneading screw 7a. Although not shown, the kneading screw 7 having a thickness of 1 / 8D also has two types of hexagonal holes with different orientations similar to the kneading screws 7a and 7b shown in FIGS. 4 (a) and 4 (b). There is.

As shown in FIGS. 6A to 6D, kneading screws 7a and 7b having a substantially elliptical appearance are appropriately combined so that hexagonal holes formed in the shaft cores coincide with each other. Thus, it is possible to make a combination in which the vertices of the ellipse are displaced at any angle of 30 °, 60 ° and 90 °.
Specifically, the combination in which the deviation of the vertex of the ellipse is 30 ° or 90 ° is obtained by combining kneading screws 7a and 7b having different hole orientations as shown in FIGS. 6 (a) and 6 (d). The combination in which the deviation of the vertex of the ellipse is 60 ° can be obtained by combining kneading screws 7a and 7b having the same hole direction as shown in FIGS. 6 (b) and 6 (c). Can be made.

A combination in which the vertex of the ellipse is displaced in the same direction as the spiral direction of the ball screws 5a, 5b, 5c in the state assembled to the core rod is referred to as forward (F). The combination in which the vertex of the ellipse is shifted in the same direction as the spiral traveling direction of the reverse screw 6 is called reverse (R). Therefore, there is no distinction between forward and reverse in the 90 ° combination.
The stirring force increases in the order of 30 ° forward (30F), 60 ° forward (60F), 90 °, 60 ° reverse (60R), and 30 ° reverse (30R).

  Ball screw 5a, 5b, 5c, reverse screw 6, KD type kneading screw 7a so that a series of processes are continuously performed within the entire length of cylinder 1 in a limited length of cylinder 1. 7b and a TKD type kneading screw 8 must be combined. In this combination, the length of each of the above-mentioned members set based on the maximum diameter 1D of the ball screw 5 (see FIG. 3A) is used. Must be combined in consideration.

  The configurations of the first and second screws 3a and 3b shown in FIG. 2 and the temperatures of the cylinder blocks C1 to C11 are obtained by using pulp, polyvinyl alcohol (PVA), starch and water as raw materials for the biodegradable foamed molded product. This is an example suitable for extrusion molding with uniform stirring, mixing and kneading. The upper table in FIG. 2 constitutes cylinder positions and control temperatures of the cylinders corresponding to the first and second screws 3a and 3b shown below the table, and the first and second screws 3a and 3b. The kind of member is shown.

In the column of screw components in the table, “4/4”, “3/4”, and “2/4” represent the helical pitch of the ball screw, and “R” represents the reverse screw.
In the same column, “KD60F” indicates that the KD type kneading screw is assembled in the forward direction with a 60 ° deviation, and “KD30R” indicates that the KD type kneading screw is in the reverse direction with a 30 ° deviation. “KD60R” indicates that the KD type kneading screw is assembled in the reverse direction with a 60 ° deviation.

  In the same column, “TKD30R” indicates that the TKD type kneading screw is assembled in the reverse direction with a 30 ° offset, and “TKD90” indicates that the TKD type kneading screw is assembled with the 90 ° offset. “TKD60F” indicates that the TKD type kneading screw is assembled in the forward direction with a 60 ° deviation, and “TKD60R” indicates that the TKD type kneading screw is reverse with a 60 ° deviation. Indicates that they are assembled in the direction.

In the column of the cylinder position in the same table, “Liquid (1)” and “Liquid (2)” indicate that liquid addition is performed at the position. In the same column, “Liquid (3)” is also indicated, which indicates that the liquid can be added at that position. However, liquid addition from the position of “Liquid (3)” is not performed in this embodiment.
Further, the top column of the table is divided for each length 1D as a reference for assembling the screws, and in this embodiment, it can be seen that the total length of the first and second screws 3a and 3b is 42D.

As shown in FIG. 2, the first and second screws 3 a and 3 b are “first feeding region”, “pulp dispersion region”, “PVA dissolution (heating) region” from the proximal end side toward the distal end side. The “preceding raw material and water mixing (cooling) region”, the “second feed region”, and the “α-ized region” are continuously connected. The first and second screws 3a and 3b are configured such that a plurality of ball screws and a plurality of kneading screws are alternately combined as a whole.
In FIG. 2, each of the above regions is divided by a solid line or a broken line for convenience, but this is for ease of explanation. Actually, adjacent regions act while affecting each other, and are not clearly separated as shown in FIG. In particular, the areas separated by broken lines are strongly related to each other. The same applies to other embodiments described later.

In the “first feeding area” corresponding to the cylinder C1, pulp and PVA supplied from the hopper 2 (see FIG. 1) and water (about 30 to 40 ° C.) supplied from the liquid (1) are used as “first It is sent to “pulp dispersion zone” following “feed zone”. Note that the cylinder C1 is at room temperature without any particular temperature control. This is indicated as “Nariyuki” in the upper table of FIG.
In this embodiment, the supply amount of pulp can be selected from the range of about 2.15 to 4.78 kg / h, the supply amount of PVA can be selected from the range of about 2.30 to 5.09 kg / h, and water supply The amount can be selected from the range of about 7.41 to 18.00 l / h.

Since the pulp charged into the cylinder C1 in the “first feeding area” is agglomerated, it must be crushed well and uniformly dispersed with the PVA before the PVA dissolves and develops viscosity.
For this reason, in the “pulp dispersion region” corresponding to the cylinders C2 to C4 following the “first feed region”, “KD60F” having a length of 2D and “KD60F” having a length of 1D are provided.

  In addition, the cylinders C2 to C4 are heated so that the cylinder temperature gradually increases from about 19 ° C. to about 118 ° C. in preparation for the PVA to be heated and dissolved in the “PVA melting (heating) region” corresponding to the next step. Be controlled.

  In the “PVA dissolution (heating) region” corresponding to the cylinders C5 to C8, heat is applied to the pulp dispersion formed in the “pulp dispersion region” in the previous step to dissolve the PVA in the dispersion. For this reason, the cylinders C5 to C7 are temperature controlled so as to maintain a relatively high temperature of 133 to 134 ° C. Note that the cylinder C8 is temperature-controlled at a slightly lower value of about 109 ° C. in order to prepare for the “preceding raw material and water mixing (cooling) region” as the next step.

  When applying heat to the pulp dispersion and stirring and mixing the pulp dispersion that has developed viscosity due to the dissolution of PVA, the pulp dispersion is retained in the cylinder to make it fully poured. Stirring and mixing with a kneading screw having a strong stirring force is preferable from the viewpoint of heat transfer efficiency with the cylinder and stirring and mixing efficiency.

  For this reason, in the “PVA melting (heating) region”, “KD30R” having a length of 1D is provided in each of the portions corresponding to the cylinder C5 and C6, and further, the length corresponding to the cylinder C7 is ½D in length. One “KD30R” is provided. And the reverse screw is each provided in the downstream of the location in which the kneading screw was provided.

  Since the reverse screw acts to push back the conveyed pulp dispersion material, the pulp dispersion material that has developed a viscosity due to the dissolution of PVA stays at the place where the kneading screw is provided, and is fully filled in the cylinder. Become. It is possible to efficiently stir and mix the pulp dispersion material in the full-poured state by stirring and mixing with “KD30R” having strong stirring power.

In the “preceding raw material and water mixing (cooling) region” corresponding to the cylinder C9, the heated pulp dispersion is cooled in order to dissolve the PVA in the “PVA dissolution (heating) region” in the previous step. This is to prevent a situation in which, in the “second feeding region” after the starch is added, the starch becomes lumpy due to the influence of heat and is not uniformly mixed with the pulp dispersion.
In order to cool the pulp dispersion, the cylinder C9 is temperature controlled to maintain about 39 ° C.
Moreover, in order to perform cooling more efficiently, water whose temperature is controlled at about 5 ° C. is supplied by the liquid (2) between the cylinder C8 and the cylinder C9. The supply amount of the cooling water can be selected from the range of about 6.00 to 18.00 l / h.

  After about 5 ° C. water is added as the liquid (2), it is necessary to stir and mix the pulp dispersion and water. Therefore, the portion corresponding to the cylinder C9 has “TDD90” having a length of 1 / 2D. Three places are provided. The pulp dispersion can be efficiently cooled by stirring and mixing the water at about 5 ° C. and the pulp dispersion in a cylinder C9 whose temperature is controlled at about 39 ° C. It is possible to prepare for “region”.

In the “second feed area” corresponding to the cylinder C10, the pulp dispersion cooled in the previous process and the starch supplied from a hopper (not shown) are sent to the “alpha process area” corresponding to the next process. The supply amount of starch can be selected from the range of 9.30 to 20.66 kg / h. The pulp dispersion and starch are simply mixed in the process of being sent to the “alpha-ized region” to form a starch kneaded body.
The “second feeding area” is intended to quickly send the pulp dispersion cooled in the previous process and the input starch to the “alpha-ized area” which is the next process. The “second feeding area” is mainly composed of a ball screw having a relatively high conveying speed such as a helical pitch “4/4” or “3/4”. The temperature of the cylinder C10 is controlled to a low temperature of about 29 ° C.

The starch added here is a master batch in which starch and titanium dioxide are mixed, and starch and gelatin are added to show the optimum properties as a raw material for the biodegradable foamed molded product. For convenience, it is called blended starch.
The masterbatch formulation is 850 g titanium dioxide per 19830 g starch. Add 26440 g of starch and 2000 g of gelatin to 6893 g of the master batch having such a composition, and stir for about 1 minute with a mixer to obtain a blended starch.

In the “α-ized region” corresponding to the cylinder C11, the starch kneaded body formed in the “second feed region” is heated to be α-converted to obtain an α-modified starch kneaded body.
For this reason, the temperature of the cylinder 11 is controlled to about 68 ° C., and a ball screw 4 having a helical pitch 2/4 is used to uniformly apply heat to the starch kneaded body, and the conveying speed is kept low. In addition, the “α-ized zone” has two “TKD60F” with a length of 1/2 and one “TKD60R” with a length of 1 / 2D, which is the last kneading to increase the stirring and mixing efficiency. A reverse screw is provided downstream of “TKD60R”, which is a screw, in order to achieve a full-poured state.
As a result, the starch kneaded body in a fully-poured state can be uniformly stirred and mixed with fine “TKD60F” and “TKD60R”, and the starch kneaded body can be uniformly heated to obtain a pregelatinized starch kneaded body. it can.

The pregelatinized starch kneaded body thus obtained is then conveyed to the forming cylinder 9 and extruded from the outlet 9a of the forming cylinder 9 as a rod-shaped kneaded body. Extruded rod-shaped kneaded bodies are cut at predetermined lengths and used as raw materials for biodegradable foamed products.
In this embodiment, the length of 1D is about 47 mm, and the rotational speeds of the first and second screws 3a and 3b are about 150 to 300 rpm.

Embodiment 2
The extruder which concerns on Embodiment 2 of this invention is demonstrated based on FIG. FIG. 8 is a diagram corresponding to FIG. 2 of the extruder according to the second embodiment.

  The extruder according to Embodiment 2 of the present invention is obtained by changing the configuration of a pair of screws 3 (see FIG. 2) inserted into the cylinder 1 of the extruder 100 according to Embodiment 1 (see FIG. 1). The other points are the same as those of the extruder 100 according to the first embodiment.

  As shown in FIG. 8, the pair of screws 203 used in the extruder according to the second embodiment includes a first screw 203a and a second screw 203b, and the first and second screws 203a and 203b are basically the same. It has the same configuration.

In Embodiment 1 described above, in the “pulp dispersion region” in which pulp, PVA and water are stirred and mixed to form a pulp dispersion, two portions of “KD60F” having a length of 2D are provided in portions corresponding to the cylinders C2 to C3. However, in the present embodiment, in order to perform more uniform stirring and mixing, the “KD60F” is replaced with “TKD90” having a stronger stirring force.
That is, in this embodiment, two portions of “TDD90” having a length of 2D are provided in the portion corresponding to the cylinders C2 to C3 of the “pulp dispersion region” forming the pulp dispersion, so that the pulp, PVA, and water are more uniform. The mixture is stirred and mixed. Other conditions relating to the manufacturing are the same as those in the first embodiment.

Embodiment 3
An extruder according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 9 is a view corresponding to FIG. 2 of the extruder according to the third embodiment.

  The extruder according to Embodiment 3 of the present invention is obtained by changing the configuration of a pair of screws 3 (see FIG. 2) inserted into the cylinder 1 of the extruder 100 according to Embodiment 1 (see FIG. 1). The other points are the same as those of the extruder 100 according to the first embodiment.

  As shown in FIG. 9, the pair of screws 303 used in the extruder according to the third embodiment includes a first screw 303a and a second screw 303b, and the first and second screws 303a and 303b are basically the same. It has the same configuration.

In the first embodiment described above, the region corresponding to the cylinders C2 to C4 is a “pulp dispersion region” in which pulp, PVA, and water are stirred and mixed to form a pulp dispersion. However, in the third embodiment, the region is more uniform. And in order to perform reliable stirring and mixing, a portion corresponding to the cylinders C2 to C6 is defined as a “pulp dispersion region”.
That is, in the third embodiment, the length of the “pulp dispersion region” is extended as compared with the first embodiment in order to obtain a pulp dispersion that is more uniformly stirred and mixed.

As shown in FIG. 9, in the third embodiment, the “pulp dispersion region” has two “KDD 90” s extending over the length 2D from the proximal end side toward the distal end side, and three “KD90s” extending over the length 2D, One “KD90” is provided over a length of 1 / 2D.
Thus, in Embodiment 3, a kneading screw having a total length of 10.5D is provided in the “pulp dispersion region” extended by two cylinders from Embodiment 1, and the pulp dispersion is In manufacturing, consideration is given to more uniform and reliable stirring and mixing.

The cylinders C5 and C6 corresponding to the end of the “pulp dispersion region” have a cylinder temperature of about 40 ° C. and about 40 ° C. in preparation for the PVA being heated and dissolved in the “PVA dissolution (heating) region” corresponding to the next step. The temperature is controlled to 80 ° C., respectively.
On the other hand, in the above-described first embodiment, the cylinder C4 corresponding to the end of the “pulp dispersion region” has a cylinder temperature (about 134 ° C.) close to the cylinder temperature (about 134 ° C.) of the “PVA dissolution (heating) region” in which PVA is heated and dissolved. The temperature is controlled so that the temperature rises to 118 ° C.
Therefore, the third embodiment has a larger temperature difference between the “pulp dispersion region” and the “PVA dissolution (heating) region” than the first embodiment, and is more “pulp dispersion than the first embodiment from the viewpoint of temperature control of the cylinder. It can be said that the boundary between the “region” and the “PVA dissolution (heating) region” is clarified.

In the third embodiment, as described above, the “pulp dispersion region” is extended by two cylinders, so that the “PVA dissolution (heating) region” for heating and dissolving PVA is shortened by two cylinders.
That is, in Embodiment 1 described above, the temperature of the cylinders C5 to C7 is controlled to about 133 to 134 ° C, and the temperature of the cylinder C8 is about 109 ° C in preparation for the "preceding raw material and water mixing (cooling) region" as the next step. Although controlled, in this embodiment, only the two cylinders C7 and C8 are in the PVA melting (heating) region, and the temperature is controlled to about 134 ° C., respectively.

  In other words, in the above-described first embodiment, three cylinders are provided with a temperature controlled to about 133 to 134 ° C. in order to dissolve PVA, and further, gradually prepared for the “preceding raw material and water mixing (cooling) region”. The section for lowering the temperature is provided for one cylinder. In this embodiment, the section for temperature control to a high temperature of about 133 to 134 ° C. is shortened by one cylinder, and the section for gradually lowering the temperature is eliminated. ing. As a result, the temperature difference between the “PVA melting (heating) region” and the “preceding raw material and water mixing (cooling) region” is larger than that in the first embodiment, and this embodiment is viewed from the viewpoint of cylinder temperature control. It can be said that the boundary between the “PVA dissolution (heating) region” and the “preceding raw material and water mixing (cooling) region” is clarified as compared with the first embodiment.

The pulp dispersion cooled through the “preceding raw material and water mixing (cooling) region” is mixed with the starch in the “second feeding region” to form a starch kneaded body, and further heated in the “pregelatinized region” to be pregelatinized starch. Although the kneaded body is used, the “second feeding region” and the “alpha-ized region” are the same as those in the first embodiment.
Further, other various conditions relating to the manufacturing are basically the same as those in the first embodiment except for the matters described above.

Embodiment 4
The extruder which concerns on Embodiment 4 of this invention is demonstrated based on FIG. FIG. 10 is a view corresponding to FIG. 2 of the extruder according to the fourth embodiment.

  The extruder according to the fourth embodiment of the present invention is obtained by changing the configuration of a pair of screws 3 (see FIG. 2) inserted into the cylinder 1 of the extruder 100 (see FIG. 1) according to the first embodiment. The other points are the same as those of the extruder 100 according to the first embodiment.

As shown in FIG. 10, the pair of screws 403 used in the extruder according to the fourth embodiment includes a first screw 403a and a second screw 403b, and the first and second screws 403a and 403b are basically the same. It has the same configuration.
The first and second screws 403a and 403b have substantially the same configuration as the first and second screws 303a and 303b of the extruder according to the third embodiment.

  That is, in the above-described Embodiment 3, “KD90” having a length of 2D is used as the kneading screws located at the third and fourth positions from the proximal ends of the first and second screws 303a and 303b. In the present embodiment, the above “KD90” is replaced with “TKD90” capable of more uniform stirring and mixing. Others are the same as those of the above-described third embodiment, including various conditions relating to manufacturing.

  In the above-described first to fourth embodiments, the cylinder positions shown in the tables of FIGS. 2 and 8 to 10 are for reference, and the actual cylinder length is The length is slightly different from the length divided in the tables of the above figures.

In the working examples , the raw materials of the biodegradable foamed molded products are manufactured using the extruders according to the above-described first to fourth embodiments, the biodegradable foamed molded products are manufactured from the manufactured raw materials, and the pulp Dispersibility was compared. Details are as follows.

  First, the raw material of the biodegradable foam molded product was manufactured using the extruder according to Embodiment 1. The supply amount of pulp is about 3.10 kg / h, the supply amount of PVA is about 3.31 kg / h, and the supply amount of water (about 35 ° C.) from the position of the liquid (1) is about 10.95 l / h. h, the supply amount of water (about 5 ° C.) from the position of the liquid (2) was about 9.69 l / h, and the supply amount of starch (prepared starch) was about 14.22 kg / h.

The raw material produced by the above blending is cut into an appropriate amount, supplied to a mold for foam molding (not shown), heated in the mold, foamed and fired, and a container as shown in FIG. A biodegradable foamed molded product 10 was produced.
Thereafter, the manufactured biodegradable foamed molded article 10 was watermarked with light, and the presence or absence of unmelted pulp was visually determined. The judgment criterion was the presence or absence of a portion appearing as a shadow when watermarked with light, and if a portion appearing as a shadow was visually recognized, it was determined that unmelted pulp had occurred.

  The above procedure was also performed for the extruders according to Embodiments 2 to 4. In addition, the mixing | blending of a raw material is common also in each embodiment. The results are shown in Table 1 below.

Using the significance test for the results shown in Table 1, it was verified that the unmelted pulp was improved in the order of Embodiment 1, Embodiment 2, Embodiment 3 and Embodiment 4.
In the following description, the subscripts A, B, C, and D in the formulas mean Embodiment 1, Embodiment 2, Embodiment 3, and Embodiment 4, respectively (see Table 1).

Comparison of Embodiments 1 and 2 Null hypothesis: There is no difference in the occurrence of unmelted pulp in Embodiments 1 and 2.
Alternative hypothesis: Embodiment 2 has improved pulp unresolved than Embodiment 1.
Risk factor: 5%, one-sided test Calculate the value of Z based on the following equation (1).

According to the above equation (1), Z _{A / B} = 10.2. The limit value of the one-sided test at the 5% risk level is 1.65, and the calculated Z _{A / B} is larger than that value, so the null hypothesis is rejected.
Therefore, Embodiment 2 judges that the unmelted pulp is improved compared to Embodiment 1.

Comparison between Embodiment 2 and Embodiment 3 When tested in the same manner as in Embodiment 1 and Embodiment 2, Z _{B / C} = 10.0 is obtained, so Embodiment 3 has improved pulp unresolved than Embodiment 2. Judge that it has been.

Comparison between Embodiments 3 and 4 When the same tests as those in Embodiments 1 and 2 are performed, Z _{C / D} = 10.9 is obtained, so that the unmelted pulp is improved in Embodiment 4 over Embodiment 3. Judge that it has been.

  As a result, it was verified that the remaining unmelted pulp was improved in the order of Embodiment 1, Embodiment 2, Embodiment 3, and Embodiment 4.

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Hopper 3,203,303,403 A pair of screw 3a, 203a, 303a, 403a 1st screw 3b, 203b, 303b, 403b 2nd screw 4 Drive part 5,5a, 5b, 5c Ball screw 6 Reverse screw 7a , 7b, 8 Kneading screw 9 Molding cylinder 9a Outlet 10 Biodegradable foamed molding 100 Extruder

Claims (2)

Equipped with a temperature-controlled elongated cylinder and a pair of elongated screws that are parallel to each other in the cylinder and rotate in the same direction, each screw transports the material supplied to the cylinder from the proximal end side to the distal end side of the cylinder Using an extruder in which a plurality of ball screws and a plurality of kneading screws that stir and mix the conveyed material are alternately combined, pulp, powder or granular polyvinyl alcohol and water are stirred and mixed. A pulp dispersion is prepared, the prepared pulp dispersion is heated to dissolve polyvinyl alcohol in the dispersion, the pulp dispersion in which polyvinyl alcohol is dissolved is cooled, and the cooled pulp dispersion is kneaded with starch. was starch kneaded material to prepare, prepared starch kneaded material is heated to α turned into obtaining a α starch kneaded body The temperature of the cylinder is gradually raised from room temperature to a range of 100 to 120 ° C. when preparing the pulp dispersion, and the temperature of the cylinder is 130 to 140 ° C. when the pulp dispersion is heated to dissolve the polyvinyl alcohol. When the pulp dispersion is cooled, the temperature of the cylinder is gradually decreased from the range of 100 to 120 ° C. to the range of 35 to 50 ° C., and water of 5 to 10 ° C. is further added to the pulp dispersion. In addition, when starch is added to prepare a starch kneaded body, the temperature of the cylinder is maintained in a range of 25 to 35 ° C., and when the starch kneaded body is heated to be gelatinized, the temperature of the cylinder is set within a range of 40 to 70 ° C. The manufacturing method of the raw material of the biodegradable foam molding to maintain . Equipped with a temperature-controlled elongated cylinder and a pair of elongated screws that are parallel to each other in the cylinder and rotate in the same direction, each screw transports the material supplied to the cylinder from the proximal end side to the distal end side of the cylinder Using an extruder in which a plurality of ball screws and a plurality of kneading screws that stir and mix the conveyed material are alternately combined, pulp, powder or granular polyvinyl alcohol and water are stirred and mixed. A pulp dispersion is prepared, the prepared pulp dispersion is heated to dissolve polyvinyl alcohol in the dispersion, the pulp dispersion in which polyvinyl alcohol is dissolved is cooled, and the cooled pulp dispersion is kneaded with starch. The starch kneaded body is prepared, and the prepared starch kneaded body is heated and pregelatinized to obtain a pregelatinized starch kneaded body. When the pulp dispersion is prepared, the temperature of the cylinder is gradually increased from room temperature to a range of 70 to 90 ° C., and when the pulp dispersion is heated to dissolve the polyvinyl alcohol, the temperature of the cylinder is 130 to 140 ° C. When the pulp dispersion is cooled, the temperature of the cylinder is maintained in the range of 35 to 50 ° C., and water at 5 to 10 ° C. is further added to the pulp dispersion, and starch is added to the starch kneaded body. maintained in the range of temperature 25 to 35 ° C. of the cylinder in preparing the biodegradable expanded molded product that maintain the temperature of the cylinder when α by heating starch kneaded material in the range of 50 to 90 ° C. Raw material manufacturing method.

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