JP2000176919A - Molding method of molded product employing paper fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a drying time and prevent a weld from developing by a method wherein the flowing of a molding material in a cavity is eliminated. SOLUTION: A molding material, which is mainly made of paper fibers, starch and the water and prepared by kneading, is pre-formed in a shape, which is similar to that of a cavity 18 and is somewhat smaller than that of the cavity 18. After the pre-formed molding material 29 is a ranged onto the mold wall surface 20 of a fixed mold 1 held at 180 deg.C, the fixed mold is closed with a movable mold 5 so as to bring parting surfaces 15 and 16 tightly contact with each other in order to fill the molding material in the cavity for drying and setting the molding material. Thus, a molded product with no formation of a weld can be obtained in a short drying time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for producing a biodegradable and relatively deep product mainly composed of paper fiber such as waste paper and paper pulp, for example, a nursery container.

[0002]

2. Description of the Related Art In the case of compression molding using a molding material obtained by kneading starch and water into paper fiber, conventionally, the molding material is formed into a tablet or a pellet, and the molding material is heated to a high temperature. It is placed in the cavity of the open mold and then the mold is closed and the molding material is melted by the heat of the mold, and the molten molding material is filled into the cavity by flowing along the cavity wall. Was.

In the case of a conventional molding method for molding a molded article utilizing paper fibers by such compression molding,
There were problems as described below.

That is, the molding material must flow along its wall surface in the cavity, but when the molding material comes into contact with the cavity wall surface heated to a high temperature, it dries and forms a solidified layer at the interface. Is not sticky and does not adhere to metal, so it is filled by slip flow along the cavity wall. When the molding material is filled by slip flow into the cavity due to the formation of the solidified layer, the thickness of the solidified layer at the tip becomes thicker due to the progress of drying, and the flow is blocked. There is a problem that the product is difficult to mold.

[0005] Further, when there are a portion which is likely to slip and a portion which is unlikely to slip due to the state of the cavity wall surface,
Since the flow front has an uneven shape, there is a problem that a weld is formed to cause a strength defect and the appearance becomes uneven.

In order to solve these problems, the applicant has formed a sliding surface by forming a rough surface having a flow resistance in the filling direction of a molding material, for example, a fine grained surface on a wall surface forming a cavity. It has been proposed to prevent slip flow by providing dynamic resistance.

[0007]

In a conventional method of forming a rough surface having a flow resistance in the direction of filling a molding material on a wall surface forming a cavity to prevent a slip flow, a method of projecting a cavity is disclosed. When molding with a cavity whose surface area is extremely large relative to the area, for example, when molding a molded article having a cup-shaped depth, slip flow of the molding material flowing in the cavity can be prevented, but on the other hand, The presence of the rough surface on the cavity wall surface makes it easier for the molding material to adhere to the rough surface, so that the water vapor generated from the molding material flows through the interface with the cavity wall surface, making it difficult to release and remove the water vapor, which is required for drying and solidification. The problem that time becomes long newly occurred.

Further, the formation of a weld is prevented by preventing the slip flow. However, when a molded article having holes or windows or a molded article having corners such as a box is formed, it is inevitable. A weld is formed due to the confluence of the molding materials, and the portion where the weld is formed has a lower strength than other portions, so that there is a problem that cracks are easily generated.

According to the present invention, even when molding is performed using a cavity whose surface area is extremely large with respect to the projected area of the cavity, the time required for drying and solidification is short, the mold release is easy, and the shape of the molded product or the molded product is reduced. It is an object of the present invention to provide a molding method capable of preventing a weld from being formed due to having holes, windows, and the like.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a method for forming a molded article using paper fibers according to the present invention comprises mixing and kneading a paper fiber with a binder such as starch and water. The formed molding material has an amount necessary to form a molded article, is formed into a shape substantially similar to the cavity shape, and is arranged in a cavity of a molding die heated to a high temperature.

[0011] By doing so, it is not necessary to roughen the mold wall surface that forms the cavity, so that the steam generated from the molding material during drying and solidification can be easily released and removed. Can be easily released, and the molding material does not flow on the mold wall surface, so that the formation of a weld can be prevented.

[0012]

DETAILED DESCRIPTION OF THE INVENTION In the method for molding a molded article utilizing paper fiber according to the present invention, a starch-based binding in which 50 to 90 parts of paper fiber and starch or 20 to 50% of the starch is replaced by polyvinyl alcohol is used. Any of the materials is composed of a kneaded product obtained by adding a long-chain fatty acid salt of 0.2 to 2.0 parts to 100 parts of a mixture obtained by adding 40 to 100 parts of water to 100 parts of a mixture of 10 to 50 parts. Using a molding material, this molding material has an amount necessary to form a molded article, and has a shape substantially similar to the cavity shape, and is formed into an eye slightly smaller than the size of the cavity. After placing the molding material formed in the cavity in a state where the parting surface of the molding die heated to 120 to 220 ° C. is separated, the parting surface of the molding die is brought into close contact, and the molding material is melted. Compress And filled into the cavity, then it is to drying and solidifying.

The molding material is composed of an amount necessary to form the final shape of the molded product, and has a shape substantially similar to the shape of the cavity forming the shape of the molded product, and is slightly smaller than the size of the cavity. Since the preforming is performed, the molding material placed in the cavity is in a state where the molding material is in contact with the entire surface of the cavity wall surface and forms a solidified layer immediately before the mold clamping is completed. In addition, since the molding material disposed in the cavity does not move, the solidified layer does not move along the wall surface of the cavity, so that a rough surface for preventing the solidified layer from slipping is unnecessary, and the hole is not formed. Even in the case of a molded product having a window or a window, a weld which is a strength defect is not formed.

Further, since the cavity wall surface is not rough, the solidified layer does not come into close contact with the cavity wall surface, so that the interface between the solidified layer and the cavity wall surface facilitates the passage of water vapor and facilitates the release of water vapor. In addition, the release of the molded product becomes easy.

Since the molding material is in contact with the entire surface of the cavity wall surface, the molding material on the surface becomes a solidified layer.
Since the central layer of the molding material is in a molten state, it can flow easily. Therefore, even when the molded product has a thin portion, the molding material present in the thin portion of the cavity can easily flow to the boss, the rib, or the thick portion forming the thick portion. In addition, the molding material existing in the portion where the hole or the window is formed flows into another thick portion, and the portion where the hole or the window is formed has an extremely thin film that can be easily removed after the mold release. It is only formed.

Further, in order to preform the molding material into a shape substantially similar to the shape of the cavity and slightly smaller than the size of the cavity by preforming, for example, it can be formed by a method as described below. .

Formulation 1 comprising 50 to 90 parts of paper fiber and 10 to 50 parts of either starch or a starch-based binder obtained by replacing 20 to 50% of the starch with polyvinyl alcohol.
To 100 parts of a mixture obtained by adding 40 to 100 parts of water to 00 parts, 0.2 to 2.0 parts of a long-chain fatty acid salt is added, and the mixture is kneaded and extruded by a kneading extruder. At this time, a die is attached to the tip of the kneading extruder and extruded into a plate shape,
Alternatively, the mixture is extruded into a rod by a kneading extruder. Next, the molding material extruded into a plate shape or a rod shape is formed into a plate-shaped molding material having a predetermined thickness by using a calender roll. In the case of a plate shape by a calender roll, paper fibers oriented in the flow direction of the material by an extruder,
Since the plate-shaped molding material obtained is expanded in the perpendicular direction and is oriented in two directions, the obtained plate-shaped molding material is preferable because the thickness becomes more uniform and the physical properties become uniform.

As another method for forming a plate-like molding material, the amount of water added to the mixture of paper fiber and starch-based binder in the above is such that kneading and pelletizing are easy and drying is easy. Only an appropriate amount is first added, kneaded, extruded into pellets, and then dried to obtain dried pellets. Next, the compound 10 was added to the dried pellets.
So that the amount of water to 0 parts is 40 to 100 parts,
After adding water and impregnating the inside of the pellet, it can be extruded in a plate shape or a rod shape in the same manner as in the above case, and then rolled into a plate-shaped molding material by a calender roll.

The plate-shaped molding material thus obtained is preformed into a shape substantially similar to the cavity shape and slightly smaller than the cavity size by, for example, a drape method of vacuum forming with a male mold. be able to.

In the case of preforming, the shape is formed substantially similar to that of the cavity, and the size is determined by disposing the preformed molding material on the wall of the mold forming the cavity. At least 1-2mm between
It is preferable that there be at least a gap so that the mold wall surface does not come into contact with the molding material. When a part of the molding material comes into contact with the mold wall surface when the preformed molding material is placed in the cavity maintained at a high temperature, the part is foamed or discolored by heating and is not in contact with the mold wall surface There is a difference in the surface condition of the molded product from other portions, which is not preferable because it causes gloss unevenness and color unevenness.

Therefore, it is preferable that the size of the outer shape of the molding material to be preformed is smaller by about 2 to 5 mm than the size of the cavity. When the mold is placed in the cavity with the mold opened, it is effective if the upper end of the preformed molding material is suspended on the parting surface of the mold.

The paper fiber and the starch binder, which are the main components of the molding material used in the present invention, or the starch binder obtained by substituting a part of the starch binder with polyvinyl alcohol, are water-soluble, biodegradable and non-charged. Therefore, the molded article is also biodegradable and non-chargeable. In addition, when water is added and kneaded, it has an extremely low viscosity fluidity in a high temperature state,
It does not adhere to the vessel wall during kneading, and can be filled by flowing smoothly in the cavity of the molding die during molding. After filling, the solidified layer is dried from the surface to form a thin solidified layer, and the solidified layer does not adhere to the cavity wall surface, so that the solidified layer is constantly pressed against the cavity wall surface by the steam pressure from the inside. Therefore, the appearance dimensions of the molded body match those of the cavity, the transferability is good, molding shrinkage and warpage do not occur, and the added water is rapidly converted to steam in the cavity held at a high temperature, It can flow through the interface between the solidified layer and the cavity wall surface and can be easily released from the gap between the parting surfaces.

Further, by adding a long-chain fatty acid salt of a non-alkali metal, the metal salt of the long-chain fatty acid acts as an internal mold release agent. The workability is improved by preventing the material from sticking to the vessel wall, the die and the like. In addition, the presence of the metal salt of a long-chain fatty acid makes it difficult for the molding material to adhere to the cavity wall surface.When water added to the molding material turns into water vapor, the water vapor forms a solidified layer of the molding material. The interface with the cavity wall surface can be easily circulated.
The action of this non-alkali metal long-chain fatty acid salt has a surface-active function by a non-polar portion based on the fatty acid chain portion and a polar portion based on the non-alkali metal portion, and is insoluble in water and has water repellency, In addition, it is considered that both of the molten state and the powder state have lubricity.

Also, 50-90 parts of paper fiber and either starch-binding material or starch-based binding material obtained by substituting 20-50% of this starch-binding material with polyvinyl alcohol are used.
A blend with 50 parts is used, but when the amount of the binder such as starch binder is 50 parts or less and the amount of the binder is 50 parts or less, the reinforcing effect of the paper fiber is weakened and the mechanical strength is high. On the other hand, when the paper fiber is 90 parts or more and the blending amount of the binder is 10 parts or less, it is difficult to sufficiently bond the paper fibers, so that the surface state of the molded body becomes rough. At the same time, the mechanical strength of the molded body is undesirably reduced.

Further, the above-mentioned blend 1 of paper fiber and binder
To 100 parts, 40 to 100 parts of water are added and kneaded, but when the amount of water added is 40 parts or less, kneading is difficult to be performed smoothly, a load is applied to the kneading, and a molding material is used. It is difficult to generate a homogeneous kneaded material due to heat generation, and the kneaded molding material has a low elongation, so it is difficult to pre-mold into a shape substantially similar to the cavity shape, and
The preformed one is not preferable because it is easily broken. on the other hand,
When 100 parts or more of water is added and kneaded, the mixture becomes a kneaded material having a remarkably low viscosity, and when preformed into a shape substantially similar to the cavity shape, it is too soft and difficult to handle. Not preferred.

In addition, 100 parts of the mixture of the paper fiber, the binder and the water are mixed with a non-alkali metal long-chain fatty acid salt of 0.2 to 0.2 parts.
2.0 parts are added, but when 0.2 part or less of the non-alkali metal long-chain fatty acid salt is added, its lubricating effect is small, and it tends to stick to a vessel wall or the like in the kneading process of the molding material. In addition, in the molding process, it takes a long time to release water vapor in the molding process because it easily sticks to the cavity wall surface. Undesirably, cracks easily occur. On the other hand, when 2.0 parts or more of the non-alkali metal long-chain fatty acid salt is added, in the kneading step of the molding material, the frictional resistance with the vessel wall is reduced, so that it becomes difficult to knead uniformly in a short time. Furthermore, when the molding materials merge in the cavity, the mechanical strength at the joint is reduced, which is not preferable.

Paper fibers include wood, cotton, flax, hemp,
Pulp material for papermaking obtained from straw or the like, or used newspapers, magazines, paper such as corrugated cardboard, paperboard, cut waste paper, broken paper, waste paper, dropped paper, used waste paper generated in the papermaking process Waste paper in the form of a waste paper such as that described above can be used, and those obtained by finely pulverizing them are easy to disperse even when compounded as a molding material, and the surface of the molded body is excellent in smoothness, which is effective.

Since the starch binder or the starch-based binder as the binder has a molecular structure very similar to the paper fiber, the paper fiber can be firmly adhered and bonded to the paper fiber. Even when the wall thickness is thin, it shows high strength and high rigidity, making it difficult for warpage to occur.Furthermore, it becomes infusible when water is removed, so it is easy to release it from the mold at high temperature. .

Although the molecular structure of polyvinyl alcohol is different from that of paper fiber and starch, it has the same degree of hydrophilic group as starch in the molecule, and thus has a function of dissolving with starch and binding paper fiber. In addition, since it is a long-chain polymer and not a branched structure like starch, it has high toughness,
When used as a binder in combination with starch, toughness can be imparted to the molded article. Therefore, when a starch-based binder in which 20 to 50% of starch is substituted with polyvinyl alcohol and a polyvinyl alcohol is compounded is used, a molded article having excellent toughness and having no crack can be obtained.

The non-alkali metal long chain fatty acid salt includes
Calcium stearate, magnesium stearate,
Zinc stearate, aluminum stearate, strontium stearate, calcium laurate, magnesium laurate, zinc laurate, aluminum laurate, and strontium laurate alone or in a mixture thereof are homogeneous with paper fiber and starch. It is effective because it can be easily mixed, exhibits excellent lubricity in a powder state, and can improve workability by a lubricating effect and a releasing effect by a lubricating effect at an interface.

In the present invention, since the compression mold for filling the molding material described above is maintained at a temperature of 120 to 220 ° C., water contained in the filled molding material is not contained in the cavity. Can be quickly and smoothly converted to water vapor.

Further, in the present invention, a preformed molding material is placed on a mold wall surface forming a cavity on a fixed side or a movable side of a compression molding die heated to a predetermined temperature. Close the mold and the movable mold, fill the cavity with the molding material preformed by the heat of the mold, and allow the excess molding material to flow out of the mold. The parting surface is closely attached.

After that, the fixed side mold and the movable side mold are opened by a minute interval to form a minute gap between the parting surfaces so as to discharge and remove generated water vapor. Water vapor generated from the molding material in the cavity of the molding die held at a high temperature flows through the interface between the solidified layer formed on the surface of the molding material and the cavity wall surface, and is smoothly discharged from the gap between the parting surfaces. In addition, the molding material is dried and solidified in a short time, and the molding cycle can be shortened.

Further, according to the present invention, a parting surface of a molding die heated to 120 to 220 ° C. is formed by preforming a molding material having a shape substantially similar to the cavity shape and a size slightly smaller than the cavity. After the mold is placed in the cavity, the parting surface of the molding die is brought into close contact with the mold, and the molding material is melted and compressed to fill the cavity. A gap of 0.02 to 0.40 mm is formed, and water vapor generated from the gap is released and removed to dry and solidify.

When the gap formed between the parting surfaces is set to 0.02 to 0.40 mm, the molding material filled in the cavity no longer flows out of the mold, and the Only can be quickly released and removed.

However, if the gap is excessively opened to 0.40 mm or more, the solidified layer on the surface of the molding material is destroyed by the foaming pressure generated by the water vapor generated from the molding material, and the molding material and the water vapor are interposed between the parting surfaces. A cavity or thick burr is likely to be generated in the molded body by flowing out of the gap,
If the gap is not more than 0.02 mm and the opening is insufficient, the molding material expands due to the water vapor pressure generated in the cavity and adheres tightly to the cavity wall surface. Not preferred.

A step of forming a gap between the parting surfaces to release water vapor, then closing the gap between the parting surfaces, and forming a gap again between the parting surfaces to release water vapor. When repeated, water vapor can be efficiently and promptly released to dry and solidify. This is because the pressure of the generated water vapor causes the molding material to expand, and the solidified layer and the cavity wall surface come into close contact with each other, thereby preventing the flow of water vapor.However, the parting surface is separated to form a gap, and The molding material is compressed by bringing the sealing surface into close contact, and then the operation of separating the parting surface again to form a gap is repeated, so that a flow path for water vapor is secured at the interface between the solidified layer and the cavity wall surface. It seems to be.

When a gap is formed between the parting surfaces, it is effective to use an elastic body as an auxiliary force because the gap can be formed reliably and quickly. For example, when an elastic body such as a spring is attached to either the fixed mold or the movable mold and the parting surface is brought into close contact, the elastic body is compressed to maintain the elastic force, and the parting is performed. When the surfaces are separated from each other, the elastic force can be used as an auxiliary force.

[0039]

EXAMPLE As an example of the present invention, a case where a biodegradable seedling raising container is compression-molded will be described in detail. In addition, the seedling container to be molded has an outer dimension of 100 mm in diameter and 80 m in bottom diameter.
m, height 70mm, wall thickness 0.1m at bottom center
m and the other portions are 1.0 mm.

First, the molding material used in this embodiment will be described. Wood pulp manufactured by Azumi Filter Paper Co., Ltd. as paper fiber, corn Y manufactured by Oji Cornstarch Co., Ltd. as starch, Gohsenol NM-14 manufactured by Nippon Synthetic Chemical Industry Co., Ltd. as polyvinyl alcohol, non-alkali as internal release agent Kishida Chemical Co., Ltd. as a metal long-chain fatty acid salt
Using zinc stearate adjusted for the test in each,
A molding material was prepared by kneading at a ratio as described below.

The mixing ratio of these materials is as follows: a mixture of 70 parts of paper fiber, 30 parts of a starch-based binder composed of 70% starch and 30% of polyvinyl alcohol, and 65 parts of water.
The composition is such that 1 part of zinc stearate is added to 00 parts.

For adjusting the molding material, the total amount is 1 kg.
Then, paper fiber, starch, polyvinyl alcohol, water, and zinc stearate are weighed, stirred, and mixed in the ratio described above. Then, the stirred and mixed product was extruded by a co-rotating twin-screw kneading extruder manufactured by BorgWana Co., Ltd. to obtain a pellet-shaped molding material having a diameter of about 5 mm and a length of about 5 mm. The twin-screw kneading extruder had a screw diameter of 28 mm, an L / D of 32, kneading conditions of a cylinder and a die of 70 ° C., and a screw rotation speed of 200 rpm.

Next, processing of the pellet-shaped molding material into a plate will be described. In the case of adjusting the molding material, in the step of stirring and mixing, the step of kneading, the step of forming a pellet, and the like, part of the water initially added is lost, so when processing into a plate, this disappeared. It is necessary to replenish water equivalent to the amount of water. Then, the pelletized molding material is impregnated with water equivalent to the amount of water that has disappeared, and then extruded to a diameter of about 20 m.
m, processed into a rod shape with a length of about 100 mm.

Then, the rod-shaped molding material was rolled into a plate having a thickness of about 1.4 mm by sandwiching it between calender rolls.
It had a shape close to an ellipse of 0 mm and a minor axis of about 150 mm, had no directionality in strength at 60 to 70 ° C., was soft and showed an elongation of 20 to 40%. Then, this plate-shaped molding material is preformed using a male mold by a drape method of vacuum forming. In the case of preforming, since it is preferable to mold the seedling container as a molded product in a shape similar to the cavity shape and a size slightly smaller than the size of the cavity, the outer dimensions of the molding material to be preformed are: Diameter about 95mm, bottom diameter about 75mm, height about 67m
m, which is 3 to 5 mm smaller than the external dimensions of the molded product.

The extruder used here is a single screw extruder for hard vinyl chloride resin, and has a screw diameter of 40 mm, L / D of 28, and a die having a diameter of 20 mm. Further, a bar-shaped molding material extruded by attaching a blade to the exit of the die is cut into a predetermined length.
As the extrusion conditions, the temperature from the center to the tip of the cylinder is 70 ° C., the temperature of the die is 80 ° C., and the rotation speed of the screw is 60 rpm. The calender roll has two rolls each having a diameter of 130 mm and a length of 300 mm. The roll temperature is 70 ° C., the gap between the two rolls is 1.4 mm, and the rotation speed is 20 rpm.

Next, regarding the mold used for compression molding,
This will be described with reference to FIG.

In FIG. 1, reference numeral 1 denotes a fixed mold having a fixed mold plate 2 mounted on a fixed mounting plate 4 via a heat insulating plate 3, and 5 denotes a movable mold plate 6 via a heat insulating plate 7. A movable-side die attached to the movable-side mounting plate 8, 9 is a fixed-side mounting plate, 10 is a movable-side mounting plate, 11 is a mold opening / closing ram, and 12 is a die-mounting bolt implanted in the movable-side mounting plate 10. The free end portion 13 is loosely fitted into a through hole 14 provided in the movable-side mounting plate 8 so that the movable-side mounting plate 8 can be guided and slid by the mold mounting bolts 12. In addition, the free end portion 13 is about 3 times larger than the movable side mounting plate 8.
It protrudes 0 mm. 15 is a parting surface of the fixed mold 1; 16 is a parting surface of the movable mold 5; 17 is an auxiliary spring attached to the parting surface 16 of the movable mold 5; It has an elastic force that acts in a direction to move away from each other. 18 is the fixed mold 1
This is a cavity formed when the parting surfaces 15 and 16 are brought into close contact with each other by closing the movable mold 5 (see FIG. 1).
(B)). Reference numeral 19 denotes a mold wall surface of the fixed mold 1 that forms the cavity 18, 20 denotes a mold wall surface of the movable mold 5 that forms the cavity 18, and these mold walls 19 and 20 are formed by polished surfaces.

Numeral 21 is a means for regulating the distance when the parting surfaces 15, 16 are separated, that is, the gap size between the parting surfaces 15, 16, and one end of which is fixed to the movable mold plate 6 of the movable mold 5. A control pin fixing plate 23 having an insertion hole 22 at the other end of the fixed mold 1 opposite to the fixed mold plate 2.
And a control pin 24 fitted into the insertion hole 22, and a hole 25 provided in the fixed mold plate 2 of the fixed mold 1 so as to communicate with the insertion hole 22. When the fixed mold 1 and the movable mold 5 are closed, the insertion hole 22 and the hole 25 become concentric. Therefore, the tip 26 of the control pin 24 is inserted into the hole 25. Can be. The control pin 24
The diameter of the tip 26 is smaller than that of the hole 25 and is loosely fitted to the hole 25 of the tip 26, so that the difference between the two diameters is half, that is, the hole 25 and the tip The size of the gap formed when the parting surfaces 15, 16 are separated from each other can be restricted to the size corresponding to the gap with the gap 26.

27 is a cartridge heater for heating the fixed mold 1, 28 is a cartridge heater for heating the movable mold 5, 29 is a preformed molding material, 30 is a ring-shaped recess formed on the parting surface 16. And cavity 1
This is a so-called discard tub for storing the excess molding material flowing out from 8. 31 is 40 mm in diameter at the bottom of the seedling container,
A rib forming portion for forming a circular rib having a thickness of 1.5 mm and a height of 3.0 mm, and a thin portion 32 for forming a thin portion having a diameter of 30 mm and a thickness of 0.1 mm at the center of the bottom surface of the seedling raising container. (See FIG. 1C).

In this embodiment, the temperature of the molding die is maintained at 180 ° C. by the cartridge heaters 27 and 28, and the diameter of the tip 26 of the control pin 24 is 14.8.
mm, and the straight shape of the hole 25 is 15.0 mm so that a gap of 0.1 mm is formed between the parting surfaces 15 and 16.

Next, the case where the seedling raising container is compression-molded using the preformed molding material and the compression mold described above will be described.

First, as shown in FIG. 1A, the fixed mold 1 and the movable mold 5 are opened and the cavity 18 is opened.
The molding material 29 preformed in the shape of a seedling container is placed on the mold wall surface 20 forming the mold, and then the mold opening / closing ram 11
Is moved forward, and the fixed-side mold 1 is compressed while the auxiliary spring 17 is compressed.
When the movable mold 5 is closed, the parting surfaces 15 and 1 are closed.
6 closely adhere to each other to form a cavity 18.

The molding material 29 is first closed by closing the fixed mold 1 and the movable mold 5 so that the fixed mold 1 is first closed.
The mold is in contact with the mold wall surface 19 of the movable mold 5 while being pressed thereby, and is disposed in the cavity 18. Molding material 29 located in cavity 18
The cavity 1 is pressed against the mold wall surfaces 19 and 20 without flowing along the mold wall surfaces 19 and 20 and is in close contact therewith.
The surface which is filled in the mold 8 and comes into contact with the mold wall surfaces 19 and 20 is solidified to form a solidified layer, and the water added to the molding material 29 is heated by a mold to become steam.

The time from when the molding material 29 starts to contact a part of the mold wall surface 19 to when the mold is closed and comes into contact with the entire surface of the mold wall surfaces 19 and 20 is determined by the time of the mold opening / closing ram 11.
Is a few millimeters, so the time during which the molding material 29 that first contacts the mold wall surface 19 is very small, and this part does not change color. Therefore, the surface of the molded article is in a homogeneous state without color unevenness.

The inner layer portion of the molding material 29 filled in the cavity 18 becomes a low-viscosity fluid by heating and flows between the solidified layers, and is present in the thin-walled portion 32 and becomes excessive. The molding material is filled in a thick forming portion such as the rib forming portion 31 to form a thick portion, and excess molding material flows into the concave portion 30 from above the cavity 18 and is stored.

Next, the control pins 24 are inserted into the insertion holes 22 and the holes 25 which are concentric with each other when the parting surfaces 15 and 16 are brought into close contact with each other. Then, the regulating means 21 is set (see FIG. 1B). When the mold opening / closing ram 11 is retracted in this state, the clamping force between the fixed mold 1 and the movable mold 5 is removed, so that the parting surfaces 15 and 16
The separation is quickly and surely separated by the water pressure of the auxiliary spring 17 and the cavity 18, and a gap of 0.1 mm regulated by the regulating means 21 is formed, and the steam generated in the cavity 18 is smoothly released from the gap. Spray and dry the molded article quickly and easily.

In the initial stage when a large amount of water remains in the molding material 29, the molding material expands due to the water vapor pressure generated from the inner layer portion.
0 may be in close contact with each other to hinder the flow of water vapor.
Therefore, in this embodiment, after separating the parting surfaces 15 and 16 to form a gap, the parting surface 1
5 and 16 are brought into close contact with each other to compress the molding material, and then the process of separating the parting surfaces 15 and 16 again to form a gap is repeated, whereby the solidified layer and the mold wall surfaces 19 and 20 are repeated.
A flow passage for water vapor is to be secured at the interface with the water.
In this case, the time for separating the parting surfaces 15 and 16 is 5 seconds, the time for bringing the parting surfaces 15 and 16 into close contact and compressing the molding material is 2 seconds, and the parting surfaces 15 and 16 are One cycle of contact / separation is 7
Seconds.

After the release of water vapor is completed, the fixed mold 1 and the movable mold 5 are closed, the control pin 24 is pulled out from the insertion hole 22 and the hole 25, and the regulating means 21 is released. If the fixed mold 1 and the movable mold 5 are opened, they can be taken out as a molded product.

The composition of the raw material is the same as that of the example, and the same size as that of the example is obtained by using a molding material processed into a tablet shape having a diameter of 50 mm and having the same configuration as that shown in FIG. The case where the seedling raising container having the shape was compression-molded was defined as Comparative Example 1. In the case of Comparative Example 2, the mold wall surface 19 of the fixed mold 1 and the mold wall surface 20 of the movable mold 5
Has a roughened surface. Then, the rough surface processing is performed by using a TH-106 type embossing process of Tanako Hachikosha Co., Ltd. to form an irregular state having a Ra of 7.2 μm and an Rmax of 47 μm with a surface roughness meter, and using a sandpaper. It has a rough surface equivalent to # 600.

The drying time and the surface condition of the molded product in the above Examples and Comparative Examples are as shown in Table 1. In the case of Comparative Example 1, a weld was formed on the surface of the molded product.

In the case of the embodiment, since the release of water vapor is smoothly performed, the drying time is remarkably reduced as compared with the case of the comparative example 2, the variation in the drying time is reduced, and the molded product is free from cracks. No gloss is excellent. On the other hand, in the case of Comparative Example 2, since the mold wall surface is rough, the drying time is long and the variation is large,
Further, the gloss of the surface of the molded product is inferior due to the transfer of the rough surface. Further, in the case of Comparative Example 1, the drying time is shorter and the variation is smaller than in the case of the example, but since the molding material flows in the cavity while slipping on the mold wall surface, a large number of welds are formed on the molded product. It was formed, the surface was not homogeneous, and many cracks and uneven flow were observed.

[0062]

[Table 1]

[0063]

The present invention is embodied in the form described above and has the following effects.

The molding material is formed in an amount necessary for forming a molded article, and is preliminarily formed into a shape substantially similar to the cavity shape, and is arranged in the cavity, so that the molding material slips and flows along the mold wall surface. Disappears. Therefore, it is not necessary to form a rough surface for preventing slipping on the mold wall surface that forms the cavity, and it can be a polished surface, so that the release of generated steam can be easily removed and the molded product can be released easily. Thus, the formation of a weld can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a compression molding die used in an embodiment of the present invention, wherein (a) shows a state where the die is open, (b) shows a state where the die is closed, (C) is an enlarged explanatory view of a portion A in (b).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed side mold 5 Movable side mold 15, 16 Parting surface 18 Cavity 19, 20 Mold wall surface 29 Molding material

Continuation of the front page (72) Inventor Mitsuyoshi Maruno 1-3-7 Oinmachi, Moriguchi-shi, Osaka Daiho Kogyo Co., Ltd. (72) Inventor Atsushi Fukuda 1-3-7 Oinmachi, Moriguchi-shi, Osaka Daiho Within Industrial Co., Ltd. (72) Inventor Masahiko Funaki 1-3-7 Oinmachi, Moriguchi-shi, Osaka Daiho Kogyo Co., Ltd. F-term (reference) 2B260 AA12 AA20 BA04 BA15 BA19 BA30 CC02 CD30 DB11 DC14 EA05 EA13 EB02 EB05 EB06 EB19 EB21 EB42 EC08 EC18

Claims (2)

[Claims] 1. Water is added to 100 parts of a blend of 50 to 90 parts of paper fiber and 10 to 50 parts of starch or a starch-based binder obtained by replacing 20 to 50% of the starch with polyvinyl alcohol. A molding material consisting of a kneaded product obtained by adding 0.2 to 2.0 parts of a long-chain fatty acid salt to 100 parts of the mixture added to 100 parts is used, and the molding material has an amount necessary to form a molded article. And formed into a shape substantially similar to the cavity shape.
After placing the parting surface of the heated mold in the cavity, the parting surface of the mold is brought into close contact, the molding material is melted and filled into the cavity, and then dried and solidified. Molding method using molded paper fiber. 2. Water is added to 100 parts of a blend of 50 to 90 parts of paper fiber and 10 to 50 parts of a starch or a starch-based binder obtained by replacing 20 to 50% of the starch with polyvinyl alcohol. A molding material consisting of a kneaded product obtained by adding 0.2 to 2.0 parts of a long-chain fatty acid salt to 100 parts of the mixture added to 100 parts is used, and the molding material has an amount necessary to form a molded article. And formed into a shape substantially similar to the cavity shape.
After placing in the cavity with the parting surface of the heated molding die separated, the parting surface of the molding die is brought into close contact, the molding material is melted and filled into the cavity, and then the molding is performed. A method for molding a molded article using paper fibers which forms a gap of 0.02 to 0.40 mm by separating a parting surface of a mold and releases and removes water vapor generated from the gap to dry and solidify.