JPH0818340B2 - Method for producing porous structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a porous structure.

[0002]

2. Description of the Related Art FIGS. 7 and 8 show, for example, JP-A-4-261.
FIG. 8 is a vertical cross-sectional view of the blower shown in Japanese Patent Publication No. 834, in which 1 is a fan casing made of a porous sound-absorbing material, and 2 is an impeller that is housed in the fan casing 1 and driven by an electric motor 3. Reference numeral 4 is a suction port, and 5 is a discharge port. As a related publication, Japanese Patent Laid-Open No. 2-289333.
And JP-A-3-79642.

FIG. 9 is a cross section of a conventional mold used for manufacturing a porous structure such as the fan casing 1, 6 is a concave mold, and 7 is a convex mold, which has good heat conduction. It is made of metal. Reference numeral 10 is a wall of the concave mold 6; 11 is a wall of the convex mold 7; 12 is a space formed by the concave mold 6 and the convex mold 7. Further, 14 is a material charging port attached to the concave side mold 6, and 16 is a steam hole incorporated in the concave side mold 6 and the convex side mold 7. 4 and 5 and 6 show the steps from material feeding to mold release.

A conventional porous structure is formed by the mold having the above-mentioned structure. For example, a case where a thermoplastic granular material is used as a raw material will be described. It has a space larger than the volume of. Figure 5 shows the state in which the material is loaded in the above state,
While continuing to pressurize, steam is passed through this space to heat and soften the material and push it to a predetermined volume to bring the sound absorbing effect to a filling rate of 70 to 80%. This pressure is 10kg / cm ²
~ A few Ton / cm ² . After heating, the mold and the molded product are cooled with water to a temperature at which the molded product is not deformed, and the molded product is taken out of the mold.

[0005]

The conventional method for producing a porous structure has the above-mentioned structure, and in order to heat and soften the material under pressure and transmit the applied pressure to each material. A large amount of the surface close to the mold is compressed, resulting in insufficient compression at the center of the molded product, resulting in a difference in the fusion state. Also, the density tends to increase as it approaches the mold surface, and tends to decrease in the central part of the molded product. In addition, the applied pressure is 10 kg / cm ² or more, which is 2 to 3 times that of expanded polystyrene, and the heating steam pressure is 2 to 3 times.
At 3 kg / cm ² , this is also high, which is equivalent to 2 to 3 times, exceeding the limit of the polystyrene foam molding machine, and there was a problem in terms of machine rigidity and safety.

The present invention has been made in order to solve the above-mentioned problems, and makes it possible to reduce the heating steam pressure, the applied pressure, the uniform fusion state, and the uniform molded product density. In addition, it is an object of the present invention to obtain a method for manufacturing a porous structure capable of obtaining an optimum filling rate capable of exhibiting performance when used as a functional material (for example, a sound absorbing material).

[0007]

Means for Solving the Problems Claim 1 according to the present invention.
The method of manufacturing a porous structure, the step of introducing a resin granular material containing a foaming agent into the space formed by the concave mold and the convex mold, and pressurizing the material with both molds When,
A step of sending steam into the space formed by the two molds to heat the material, and in the step of introducing the material, a space after forming a space formed with a gap between the two molds The material is charged in a larger state, and in the step of pressurizing the material, both molds are completely closed and compressed to a predetermined molded product volume.

According to a second aspect of the present invention, there is provided a method of manufacturing a porous structure, which comprises a step of introducing a resin granular material containing a foaming agent into a space formed by a concave mold and a convex mold, A step of sending steam into the space formed by the two molds to heat the material, and a space formed without a gap between the two molds in the step of charging the material, that is, molding Hold the volume equal to the latter volume.

In the method for producing a porous structure according to a third aspect of the present invention, the raw material is substituted with an inorganic gas (for example, air, carbon, nitrogen, oxygen, etc.) having the same function as the foaming agent. is there.

[0010] manufacturing method of a porous structure of claim 4 according to the present invention, the density is reduced with respect to the original material finishing already primary foaming material as the raw material, yet it is made to remain still blowing agent It was used as the secondary raw material.

[0011] Inorganic manufacturing method of the invention according claim 5 of the porous structure, the density is reduced with respect to the original material finishing already primary foaming material as a raw material, yet having a foaming agent Equivalent A secondary material in which gas remained or foamed material was stored inside by compressed air was used.

[0012]

In the method for producing a porous structure according to the first aspect of the present invention, steam is discharged into the mold to heat the material, the particles are slightly expanded by the foaming agent inside the material particles, and the partial surfaces of the particles are fused. It is the one to be confused. In the step of introducing the material, when the space formed with a gap between the two molds is larger than the volume after molding, the shape of the material, the size of the particles, the weight of the particles, etc. are different. This is to compensate for the decrease in the flying energy of the particles and the decrease in the filling rate. After the completion of filling, the mold is closed to obtain a predetermined molded product volume.

The method for manufacturing a porous structure according to a second aspect of the present invention is the same as that described above, but a space formed without a gap between the two molds in the step of introducing the raw material, that is, a volume after molding. It is suitable for when the conditions such as the shape of the material, the particle diameter, and the weight of the particles are appropriate.

According to a third aspect of the present invention, in which the porous structure is produced, air is stored in the material particles in place of the foaming agent, and steam is discharged into the mold to heat the material. The inorganic gas is expanded to fuse the partial surfaces of the particles to each other.

The method for producing a porous structure according to a fourth aspect of the present invention is a production method using a raw material in which a raw material containing a foaming agent is foamed by some method and a foaming agent remains inside the raw material. Is the way.

In the method for producing a porous structure according to a fifth aspect of the present invention, the raw material is a secondary raw material obtained by foaming the raw material by some method, and the foaming agent does not remain inside the raw material, and the inorganic gas is stored inside the raw material. A manufacturing method using. If the self-expansion force of the inorganic gas inside the material is not sufficient for fusion bonding, place this material in a container and apply pressure from the outside with compressed air to shrink the material volume and place the material in the mold in that state. throw into. When this pressure is released when the filling of the material is completed, the material pushes the particles against each other in an attempt to return to the original material particle size due to the restoring force of the internal inorganic gas.
This is a method for producing a porous body that is fused by this pressure.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view of a mold according to an embodiment of the present invention, in which the same or corresponding parts as in the conventional example are designated by the same reference numerals.

In the figure, reference numeral 13 is a material filling device having the charging port attached to the wall portion 10 of the mold, 14 is a material charging port of the charging device 13, 15 is a material suction port of the charging device 13, and 16 is a mold. The vapor holes are attached to the wall portions 10 and 11, 19 is the vapor supply port attached to the concave mold 6, and 21 is the vapor chamber. Reference numeral 20 is a steam supply port attached to the convex mold 7, and reference numeral 22 is the steam chamber.

2 and 3 are views showing a manufacturing process in the present invention. FIG. 2 is a process of inserting a material, and FIG.
It is a figure which shows the process of heating, 25 is a raw material.

Next, a method of forming a porous structure by using the granular material of the thermoplastic resin as a raw material using the mold of FIG. 1 will be described. The concave mold 6 and the convex mold 7 are closed to form a space in the mold. Compressed air is caused to flow through the filling device 13 and the granular material is sucked through the material suction port 15 by the internal pressure difference. The sucked material is filled with air into the space 12 in the mold from the material charging port 14.

In the step of inserting this material, a state in which a gap 23 is provided within the range in which the charged material 25 does not leak out of the space 12 without completely closing the concave mold 6 and the convex mold 7. Fill the material with. (Fig. 2)

After the completion of filling, the mold is completely closed while being pressurized, and steam is supplied from the steam supply ports 19 and 20 to supply steam to the steam chamber 2.
The material 25 is heated through the 1, 22 steam holes 16. The foaming agent or inorganic gas of the material to be heated expands, the materials are locally subjected to compressive stress, and the part is fused by heat.
(FIG. 3) After the heating is completed, for example, water is poured onto the mold and the molded product, cooled to a temperature at which the molded product is not deformed, and taken out from the mold.

In the step of inserting the material, when the concave side mold 6 and the convex side mold 7 are completely closed and the material is charged, the heating is performed in the state of FIG. 3 while the heating is performed in the state of FIG.

The method for producing a porous chamber structure according to the present invention has been applied to the prior art, for example, it is instantaneously present in the process of producing expanded polystyrene foam, but it is not industrially practical, and thus the present application.

Since the blowing agent contained in the present expanded polystyrene foam is 5% by weight or more, the time from the start of heating with steam until the optimum filling rate or porosity is obtained is shown in FIG.
As shown in 0 (graph 1), the time is extremely short, and the reality is that even with the current control technology, control is impossible.

In order to solve the above-mentioned problems, the present invention uses the amount of the foaming material contained in the material, for example, when butane gas is used as the foaming agent, when the content is suppressed to 2% by weight or less, A good porous structure was stably obtained. (FIG. 11 (graph 2)) In other words, the amount of the foaming agent is adjusted so that the optimum filling rate does not exceed 70 to 80% even if the particles expand by heating.

[0027]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, it can be formed in a region where the heating temperature slightly exceeds the softening point of the material by manufacturing it with a material having a foaming function, and the steam pressure decreases and The time is shortened, and the partial fusion is performed uniformly without being affected by the pressing force. In addition, this manufacturing method allows the use of foamed raw materials, which reduces the density of molded products.
Kusuru it can be.

[Brief description of drawings]

FIG. 1 is an explanatory view of a mold showing an embodiment of the present invention.

FIG. 2 is an explanatory view showing a manufacturing process of the present invention.

FIG. 3 is an explanatory view showing a manufacturing process of the present invention.

FIG. 4 is an explanatory diagram of a material charging process of a conventional manufacturing process.

FIG. 5 is an explanatory diagram of a material pressure and heat softening step in a conventional manufacturing process.

FIG. 6 is an explanatory diagram of a cooling and releasing process of a conventional manufacturing process.

FIG. 7 is a vertical cross-sectional side view of a blower having a porous fan casing.

8 is a vertical sectional front view of FIG. 7;

FIG. 9 is a sectional view of a mold used for molding a conventional porous structure.

FIG. 10 is a graph showing changes in the filling rate or porosity of a foaming agent under heating.

FIG. 11 is a graph showing changes in filling rate or porosity when the foaming agent of the present invention is used.

[Explanation of symbols]

 1 Fan casing 2 Impeller 3 Electric motor 4 Suction port 5 Discharge port 6 Concave side mold 7 Convex side mold 10,11 Wall part 12 Space 13 Filler 14 Material input port 15 Material suction port 16 Steam hole 17 Movable wall 18 Cylinder 19,20 Steam supply port 21,22 Steam chamber 23,24 Gap 25 Material

Claims (5)

[Claims] 1. A step of introducing a resin granular material containing a foaming agent into a space formed by the concave mold and the convex mold,
There is a step of pressurizing the material with both molds and a step of sending steam into the space formed by both molds to heat the material, and a gap between the two molds in the step of charging the material. Characterized in that the material is charged in a space formed by forming a space larger than the volume after molding, and in the step of pressurizing the material, both molds are completely closed and compressed to a predetermined molded product volume. And a method for producing a porous structure. 2. A step of introducing a resin granular material containing a foaming agent into a space formed by the concave mold and the convex mold,
A step of sending steam into the space formed by the two molds to heat the material, and a space formed without a gap between the two molds in the step of charging the material, that is, after molding The method for producing a porous structure, characterized in that the porous structure is held in a state of being equal to the volume of the porous structure. 3. The method according to claim 1, wherein the material is a substitute for an inorganic gas having the same function as the foaming agent. 4. Beyond the material already primary foam density decreases to the original material, yet claim 1 or claim 2, characterized in that a secondary material that is left of the still blowing agent A method for producing the porous structure described. 5. A material already density decreases to the original material finishing primary foaming, moreover inorganic gas with the blowing agent and the same function is allowed stored therein by the remaining or compressed air foamed material two It is the following raw material, The manufacturing method of the porous structure of Claim 1 or Claim 2 characterized by the above-mentioned.