JP4244070B1 - Method for producing foamed resin composite structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a foamed resin composite structure that is lightweight but does not cause water leakage.
SOLUTION: There are communication holes communicating from one surface to the other surface, and the viscosity of the resin dissolved or dispersed in a solvent on the upper surface of the base material 1 having an average diameter of the communication holes of 10 to 150 μm is 2000 mPa · The flowable material 4 of s or less is disposed, and the decompression device 3 is operated to decompress the decompression chamber 2d. Thereby, since the fluid material 4 permeates the communication hole of the base material 1 and the communication hole is closed, it is possible to manufacture a foamed resin composite structure that is lightweight but does not cause water leakage.
[Selection] Figure 2

Description

  The present invention relates to a method for manufacturing a foamed resin composite structure using a base material made of foamed resin.

  Conventionally, as a method for producing a foamed resin molded product, for example, a method described in JP-A-9-39018 (Patent Document 1) is known. FIG. 16 is a schematic diagram of a foamed resin molding machine described as a prior art in such a patent publication. Hereinafter, the molding process of the foamed resin molded product using the foamed resin molding machine will be described.

  First, the mold opening / closing cylinder 300 is operated to move the male mold 100 horizontally toward the female mold 200 to perform mold clamping. Subsequently, a foamed resin molding raw material 310 such as foam beads is filled in the cavity 360 formed on the mating surface of the male mold 100 and the female mold 200. Subsequently, heated steam flows from the inflow pipe 330 into the male mold 100 and the female mold 200 to heat the mating surfaces, and the foamed resin molding raw material 310 in the cavity 360 is melted. Subsequently, cooling water flows in from the inflow pipe 330, and the flowing cooling water is sprayed from a plurality of spray nozzles 350 formed in the male mold 100 and the female mold 200 to cool the mating surfaces. Subsequently, the mold opening / closing cylinder 300 is operated to move the male mold 100 horizontally to open the mold. Subsequently, the ejector 320 is moved so that the ejector pin 370 protrudes from the inside of the female mold 200 into the cavity 360, and the foamed resin molded product solidified in the cavity 360 is released.

Japanese Patent Laid-Open No. 9-39018 (second paragraph, FIG. 8)

  If priority is given to reducing the weight of foamed resin molded products, and the foaming ratio of the foamed resin molding raw material is increased, the closed cells formed by fusing adjacent foamed cells communicate with each other, from one surface to the other. A communicating hole that communicates is formed. For this reason, when a foamed resin molded product is used for a drain pan such as an air conditioner or a refrigerator, or a building material, there is a problem that water leaks from the communication hole.

  Accordingly, an object of the present invention is to realize a foamed resin composite structure that is lightweight but does not cause water leakage.

  In order to achieve the above object, according to the present invention described in claims 1 to 9, the closed cell structure is formed by fusing adjacent foam cells (1c). In addition, there is a communication hole (1d) communicating from one surface (1a) to the other surface (1b) due to communication between the closed cells, and the average diameter of the communication holes is 10 to 150 μm. The material (1), the flowable material (4) in which the resin is dissolved or dispersed in a solvent and the viscosity is 2000 mPa · s or less, and the pressure on the other surface is lower than the one surface. Preparing a differential pressure generating device (3) for generating a differential pressure between the one surface and the other surface, and arranging the flowable material on the one surface; The differential pressure generator generates a differential pressure between the one surface and the other surface. A second step of allowing the flowable material disposed on the one surface to permeate the communication hole and bringing the communication hole into a non-communication state. The technical means of selecting from 18 to 95 vol% depending on the average diameter of the holes is used.

  According to a second aspect of the present invention, in the method for producing a foamed resin composite structure according to the first aspect, a powder is dispersed in the solvent, and a volume ratio of the resin and the powder to the solvent is the communication rate. The technical means of selecting from 18 to 95 vol% depending on the average diameter of the holes is used.

  According to a third aspect of the invention, in the method for producing a foamed resin composite structure according to the second aspect, the technical means that the powder is at least one of a conductive powder and a magnetic powder is used.

  According to a fourth aspect of the present invention, in the method for producing a foamed resin composite structure according to the third aspect, the technical means that the conductive powder is a powder made of at least copper is used.

  According to a fifth aspect of the present invention, in the method for producing a foamed resin composite structure according to the third or fourth aspect, the technical means that the magnetic powder is a powder made of at least ferrite is used.

According to a sixth aspect of the present invention, in the method for producing a foamed resin composite structure according to the second aspect , the technical means that the powder is a powder made of at least boric acid is used.

  According to a seventh aspect of the present invention, in the method for producing a foamed resin composite structure according to any one of the first to sixth aspects, the second step is the step in which the flowable material (4) is the one. The technical means is used so as to remain on the surface (1a).

  In invention of Claim 8, in the manufacturing method of the foamed resin composite structure as described in any one of Claim 1 thru | or 7, the said fluid material (4) is an acrylic type, a synthetic rubber type, The technical means of being a solvent type or dispersion type resin comprising at least one of vinyl acetate type and ethylene type is used.

  In a ninth aspect of the present invention, in the method for producing a foamed resin composite structure according to the eighth aspect, the technical means that the fluid material (4) is an aqueous resin emulsion is used.

  The base material according to any one of claims 1 to 9 is a foamed resin molded body having a shape of a mold obtained by filling a mold with a foamed resin raw material such as foam beads and then heating and foaming it. This is a foamed resin molded body prepared by fusing the foamed resin molded body itself with a heated nichrome wire or the like.

In addition, the above-mentioned foamed resin molded body includes a foamed resin molded body having a roughened predetermined surface of the foamed resin molded body itself according to the shape of the above-described mold or the above-described melt-cutting. The body is included.
In addition, the code | symbol in said parenthesis shows the correspondence with embodiment mentioned later.

(Effects of the inventions according to claims 1 to 9)
By allowing a fluid material, in which a resin is dissolved or dispersed in a solvent, to permeate through the communication holes formed in the base material, the communication holes can be made non-communication, so that water leakage does not occur while being lightweight. A foamed resin composite structure can be produced.
In addition, the flowable material that has permeated through the communication holes formed in the base material is dried and the resin contained in the flowable material is cured, whereby a foamed resin composite structure having high strength can be manufactured.

  As the fluid material, a solvent-type or dispersion-type resin composed of at least one of acrylic, synthetic rubber, vinyl acetate, and ethylene can be used. Moreover, the resin aqueous emulsion of Claim 9 can be used as such resin. In particular, when an aqueous resin emulsion is used, there are effects that the base material is not dissolved, the occurrence of VOC (Volatile Organic Compounds) is small, and the viscosity can be easily adjusted with water.

(Effect of the invention according to claim 2)
Since the powder is dispersed in the solvent, the foamed resin composite structure can have the properties of the powder.
Further, the powder is dispersed in the solvent, and the volume ratio of the resin and the powder to the solvent is selected from 18 to 95 vol% according to the average diameter of the communication holes, so that the flowable material in which the powder is not dispersed The ratio of the resin dissolved or dispersed in the solvent can be reduced as compared with the above.

(Effect of the invention according to claim 3)
Since at least one of the conductive powder and the magnetic powder is dispersed in the solvent, the foamed resin composite structure can have at least one property of conductivity and magnetism.

(Effect of the invention according to claim 4)
Since the powder composed of at least copper is dispersed in the solvent, the foamed resin composite structure can have at least conductivity and biological repellent effect.

(Effect of the invention according to claim 5)
Since the powder composed of at least ferrite is dispersed in the solvent, the foamed resin composite structure can have at least magnetism.

(Effect of the invention according to claim 6)
Since the powder composed of at least boric acid is dispersed in the solvent, the foamed resin composite structure can have at least the property of repelling living organisms.

(Effect of the invention according to claim 7)
By leaving the flowable material on one surface of the base material, it is possible to cover one surface of the base material with the resin contained in the flowable material. Even if there is a communication hole that is not present, the opening in one surface of the communication hole can be blocked by the residual resin.
Therefore, the effect of preventing water leakage can be enhanced.

Further, by leaving the powder on one surface of the base material, the surface of the base material can be given a powder property.
Furthermore, the powder adhering to the inside of the communication hole and the powder adhering to one surface of the base material are continuous, so that the powder has properties for a continuous range from one surface to the inside of the communication hole. Can be made.

<First Embodiment>
A method for producing a foamed resin composite structure according to an embodiment of the present invention will be described with reference to the drawings.

[Base material structure]
The structure of the base material for manufacturing the foamed resin composite structure will be described with reference to the drawings.
FIG. 1 is an explanatory diagram of a base material, where (a) is a perspective view of the base material, and (b) is an enlarged view of a region D shown in (a). As shown in FIG. 1B, the base material 1 is formed by aggregating a large number of foam cells 1c formed by foaming a foamed resin molding raw material such as foam beads. The respective foam cells 1c are fused to each other by heating.

  Between each foam cell 1c, the space | gap 1d is formed and each space | gap 1d is each independent. That is, the base material 1 is formed in a closed cell structure. However, some of the gaps 1d are in communication with each other, whereby the base material 1 is formed with a large number of communication holes that communicate from one surface 1a to the other surface 1b. The communication hole exists not only between the front surface and the back surface of the base material 1 but also between the front surface and the side surface or between the back surface and the side surface.

[Experiment 1]
The inventors of the present application conducted an experiment to determine the upper limit of the viscosity of the fluid material that can penetrate into the communication hole of the base material 1.

(apparatus)
An apparatus for infiltrating the fluid material into the base material 1 will be described with reference to the drawings. FIG. 2 is a longitudinal sectional view showing a state in which the base material 1 and the flowable material 4 are set in the apparatus.

  The apparatus includes a container 2 and a decompression device 3. The upper surface of the container 2 is opened, and the inside thereof is divided into two upper and lower spaces by a partition 2a. The upper space 2b is formed in a space that accommodates the base material 1 and the flowable material 4, and the lower space 2c is a decompression chamber 2d. Vents 2e that communicate from the upper space 2b to the decompression chamber 2d are formed through the middle partition 2a at a plurality of locations. The decompression chamber 2d communicates with an exhaust port 2f formed through the side wall of the decompression chamber 2d, and the exhaust port 2f is connected to the decompression device 3 through a pipe 3a. In this experiment, a vacuum pump capable of adjusting the pressure in the decompression chamber 2d was used as the decompression device 3.

(Experiment contents)
As the flowable material 4, water having a viscosity of 1 mPa · s and a vinyl acetate solution having a viscosity higher than that of water were used. Also, a plurality of flowable materials having different viscosities were prepared by diluting the vinyl acetate solution. The vinyl acetate solution was diluted with methanol. As the base material 1, a plurality of materials having EPS (Expanded Poly-Styrene: beaded polystyrene foam), different expansion ratios, and different average diameters of communication holes were prepared. Of the prepared base material 1, the smallest average diameter of the communication holes is 12 μm, and the largest is 130 μm. The thickness of each base material 1 is 25 mm. A method for calculating the average diameter of the communication holes will be described later.

  And it experimented with the following procedure. First, the base material 1 is arrange | positioned on the partition 2a of the above-mentioned apparatus. Next, the fluid material 4 is disposed on the base material 1. Next, the decompression device 3 was operated, the decompression chamber 2d was decompressed to −80 kPa, and evacuation was performed. Then, the time required for the fluid material 4 to reach the lower surface through the communication hole of the base material 1 from the start of pressure reduction was measured.

(Experimental result)
FIG. 3 is a chart showing the results of Experiment 1 for a base material having an expansion ratio of 60 times, an average diameter of communication holes of 70 μm, and a porosity (ratio of voids in the base material volume) of 3%. As shown in the figure, in the case of water having a viscosity of 1 mPa · s, it reached the lower surface of the base material 1 instantaneously from the start of pressure reduction. And in the case of the diluted product of the vinyl acetate solution whose viscosity is 500, 1000, 1500 mPa * s, the measurement time was 10 seconds, 30 seconds, and 5 minutes, respectively. In the case of a diluted product of a vinyl acetate solution having a viscosity of 2000 mPa · s, the measurement time was 15 minutes, and the solution slightly reached the lower surface.
In addition, the measurement time at each viscosity tends to be slightly longer as the average diameter of the communication holes is smaller, and slightly shorter as the average diameter of the communication holes is larger, but the average of the communication holes in the range of 12 to 130 μm. The difference in measurement time due to the difference in diameter was small.

(Conclusion)
From the above experimental results, it was found that the upper limit of the viscosity of the flowable material that can penetrate the base material 1 is 2000 mPa · s.
That is, it was found that in order to close the communication hole of the base material 1, a fluid material in which the resin is dissolved or dispersed in a solvent and the viscosity is 2000 mPa · s or less may be used.

[Experiment 2]
Next, the inventors of the present application conducted an experiment for investigating the relationship between the ratio of the resin component in the fluid material to be permeated into the base material 1 and the water stop effect. FIG. 4 is a chart summarizing the results of Experiments 2 and 3.

(Experiment contents)
In this experiment, Acronal S400 (Acronal is a registered trademark of BASF Corporation) manufactured by BASF Japan Ltd. was used as a fluid material containing resin. Acronal S400 is an aqueous emulsion of an acrylate-styrene copolymer resin, and the resin content of the stock solution is 60 vol%. Further, Acronal S400 was diluted with water to produce flowable materials having resin contents of 6, 15, 20, 25, 30, 40, and 50 vol%. In addition, the viscosity of any fluid material having a resin content of 6 to 60 vol% is 2000 mPa · s or less.

  Further, as the base material 1, a base material A having a foaming ratio of 15 times, an average diameter of communication holes of 28 μm, and a porosity of 2%, and a base material A having an expansion ratio of 60 times, an average diameter of communication holes of 70 μm, and a porosity of 3% Material B was used. All the base materials are made of EPS and have a thickness of 20 mm. The apparatus used is the same as that in Experiment 1 described above.

  And it experimented with the following procedure. First, the base material is placed on the partition 2a of the apparatus. Next, the fluid material 4 is disposed on the base material. Next, the decompression device 3 was operated, the decompression chamber 2d was decompressed to −80 kPa, and evacuation was performed. Then, the time required for the fluid material 4 to reach the lower surface through the communication hole of the base material from the start of pressure reduction was measured.

(Experimental result)
As a result, as shown in FIG. 4, in the base material A, any flowable material having a resin content of 6 to 30 vol% reached the lower surface of the base material A in 1 minute. Further, in the base material B, the fluid material having a resin content of 30 vol% reaches the lower surface of the base material B in 30 seconds, and the fluid material having a resin content of 40 to 60 vol% is 1 minute in all of the base material B. Reached the bottom.

(Conclusion)
From the above experimental results, the base material A having a communication hole with an average diameter of 28 μm can be infiltrated with an emulsion having a resin content of 6 to 30 vol% and a viscosity of 2000 mPa · s or less, and the communication hole has an average diameter of 70 μm. It was found that an emulsion having a resin content of 30 to 60 vol% and a viscosity of 2000 mPa · s or less can be permeated into the base material B.

[Experiment 3]
Next, the inventors of the present application conducted an experiment to confirm the water-stopping effect of the foamed resin composite structure produced in Experiment 2 above. The experiment was performed in the following procedure using the same apparatus as in Experiment 2 described above.

(Experiment contents)
First, the foamed resin composite structure was dried, and the evaporation component contained in the flowable material that had permeated the base material was evaporated. This drying may be left as it is or may be forced to dry by sending warm air. And the dried foamed resin composite structure is arrange | positioned on the partition 2a of an apparatus. Next, water is placed on the foamed resin composite structure. Next, the decompression device 3 was operated, the decompression chamber 2d was decompressed to −80 kPa, and evacuation was performed. And the time required for water to reach the lower surface through the communication hole of the foamed resin composite structure from the start of the pressure reduction was measured. Moreover, in order to confirm the water-stopping inside the foamed resin composite structure, the surface of each foamed resin composite structure was scratched with a depth of 5 mm.

(Experimental result)
As a result, as shown in FIG. 4, when each of the foamed resin composite structures (base material A) in which an emulsion having a resin content of 6 to 25 vol. Slightly exuded from the lower surface of the structure. On the other hand, in the foamed resin composite structure (base material A) in which the emulsion having a resin content of 30 vol% penetrated, water did not ooze out from the lower surface of the foamed resin composite structure.
In each foamed resin composite structure (base material B) in which an emulsion having a resin content of 30 or 40 vol% penetrated, water slightly oozed from the lower surface of the foamed resin composite structure, but the resin content was 50 or In each foamed resin composite structure (base material B) in which 60% of the emulsion penetrated, water did not ooze out from the lower surface of the foamed resin composite structure.

(Conclusion)
From the above experimental results, a foamed resin composite having a water-stopping effect to the inside by infiltrating an emulsion having a resin content of 30 vol% or more and a viscosity of 2000 mPa · s or less into the base material A having an average diameter of communication holes of 28 μm. It has been found that a structure can be produced. In addition, a foamed resin composite structure having a water-stopping effect to the inside is manufactured by impregnating an emulsion having a resin content of 50 vol% or more and a viscosity of 2000 mPa · s or less into the base material B having a communication hole average diameter of 70 μm. I understood that I could do it.

[Experiment 4]
Next, the inventors of the present application conducted an experiment to examine the permeability of a fluid material in which an inorganic powder was dispersed in the emulsion used in Experiment 2 described above. FIG. 5 is a chart summarizing the results of Experiment 4.

(Experiment contents)
In this experiment, copper powder MA-C04J manufactured by Mitsui Mining & Smelting Co., Ltd. was used as the inorganic powder. Three types of flowable materials (both viscosities of 2000 mPa · s or less) are prepared by dispersing 2.5, 5.0, and 7.5 vol% copper powder in Acronal S400 with a resin content of 25 vol%. It was. The base material used is made of EPS, the expansion ratio is 15 times, the average diameter of the communication holes is 28 μm, the porosity is 2%, and the thickness is 20 mm.
Then, using the same apparatus as that used in each of the above-described experiments, the permeability of the fluid material and the water-stopping property of the foamed resin composite structure were examined in the same procedure as in the above-described Experiments 2 and 3. The pressure in the decompression chamber 2d during evacuation is -80 kPa.

(Experimental result)
As a result, as shown in the permeability of FIG. 5, all of the three kinds of flowable materials reached the lower surface of the base material by evacuation for 3 minutes. As shown in the result of vacuum water filling in FIG. 5, in the foamed resin composite structure in which the flowable material in which the resin content is 25 vol% and the copper powder is dispersed in 2.5 or 5.0 vol% is infiltrated, Slightly exuded. On the other hand, in the foamed resin composite structure in which the flowable material in which the resin content was 25 vol% and the copper powder was dispersed was infiltrated, water did not ooze out from the lower surface even when evacuated for 5 minutes. Moreover, as a result of trying copper powders having different particle diameters, the copper powder has a particle diameter of 1/7 or less of the average diameter of the communication holes, that is, 4 μm (= 28 μm / 7) or less. I found out that

(Conclusion)
From the above experimental results, a fluid material having a viscosity of 2000 mPa · s or less containing 25 vol% resin content and 7.5 vol% copper powder is infiltrated into the base material A having an average diameter of the communication holes of 28 μm. It was found that the foamed resin composite structure produced in this way has a water stop effect.
In other words, a resin material and a volume ratio of copper powder of at least 32.5 vol% ≈30 vol% or more are infiltrated into a base material having an average diameter of communication holes of 28 μm, thereby providing a water stop effect to the inside. It was found that the foamed resin composite structure can be produced.

  From the results of Experiments 3 and 4, the resin component or (resin component + inorganic powder) is dissolved or dispersed at least 30 vol% or more in the base material having an average diameter of the communication holes of 28 μm, and the viscosity is It was found that a foamed resin composite structure having a water-stopping effect could be produced by infiltrating a fluid material having a viscosity of 2000 mPa · s or less. Moreover, in order to make inorganic powder reach the inside of a communicating hole, it turned out that it is desirable to use the inorganic powder which has a particle size of 1/7 or less of the average diameter of a communicating hole.

[Experiment 5]
Next, the inventors of the present application performed an experiment similar to the above Experiment 4 by changing the base material and the flowable material. FIG. 6 is a chart summarizing the results of Experiment 5.

(Experiment contents)
In this experiment, three types of flowable materials obtained by dispersing 2.5, 5.0, and 7.5 vol% copper powder in acronal S400 having a resin content of 45 vol% (both viscosities are 2000 mPa · s or less). made. The base material used is made of EPS, the expansion ratio is 60 times, the average diameter of the communication holes is 70 μm, the porosity is 3%, and the thickness is 50 mm.

(Experimental result)
As a result, as shown in the permeability of FIG. 6, the flowable material in which the resin content is 45 vol% and the copper powder is dispersed in 2.5 or 5.0 vol% is evacuated for 5 minutes. To a depth of 25 to 30 mm. Moreover, the fluid material in which the copper powder was dispersed by 7.5% penetrated from the upper surface of the base material to a depth of 20 to 25 mm by evacuation for 5 minutes.
As shown in the result of vacuum water filling in FIG. 6, in the foamed resin composite structure in which the flowable material in which the resin content is 45 vol% and the copper powder is dispersed 2.5 or 5.0 vol% is infiltrated, Slightly exuded. On the other hand, in the foamed resin composite structure in which the flowable material in which the resin content was 45 vol% and the copper powder was dispersed by 7.5 vol% was permeated, water did not ooze out from the lower surface even when evacuated for 5 minutes. Moreover, as a result of trying copper powders having different particle sizes, the copper powder has a particle size of 1/7 or less of the average diameter of the communication holes, that is, 10 μm (= 70 μm / 7) or less. I found out that

(Conclusion)
From the above experimental results, a fluid material having a viscosity of 2000 mPa · s or less containing 45 vol% resin content and 7.5 vol% copper powder is infiltrated into a base material having an average diameter of communication holes of 70 μm. It was found that the produced foamed resin composite structure had a water-stopping effect up to the inside.
In other words, a water-stopping effect can be obtained to the inside by infiltrating a flowable material having a volume fraction of the resin content and copper powder of at least 52.5 vol% ≈50 vol% with respect to the base material having an average diameter of the communication holes of 70 μm. It was found that the foamed resin composite structure can be produced.

  In addition, from the results of Experiments 3 and 5, the resin component or (resin component + inorganic powder) is dissolved or dispersed in at least 50 vol% or more with respect to the base material having an average diameter of the communication holes of 70 μm, and the viscosity is It was found that a foamed resin composite structure having a water-stopping effect could be produced by infiltrating a fluid material having a viscosity of 2000 mPa · s or less. Moreover, in order to make inorganic powder reach the inside of a communicating hole, it turned out that it is desirable to use the inorganic powder which has a particle size of 1/7 or less of the average diameter of a communicating hole.

[Experiment 6]
Next, the inventors of the present application conducted an experiment to examine the permeability of the fluid material in which the organic powder was dispersed in the emulsion used in Experiment 3 above. FIG. 7 is a chart summarizing the results of Experiment 6.

(Experiment contents)
In this experiment, polymethyl methacrylate resin powder (particle size 5 μm) was used as the organic powder. Three types of flowable materials obtained by dispersing 2.5, 5.0, and 7.5 vol% polymethyl methacrylate resin powders in acronal S400 having a resin content of 25 vol% (all viscosities are 2000 mPa · s). The following was made. The base material used is made of EPS, the expansion ratio is 15 times, the average diameter of the communication holes is 28 μm, the porosity is 2%, and the thickness is 20 mm. Then, using the same apparatus as that used in each of the above-described experiments, the permeability of the fluid material and the water-stopping property of the foamed resin composite structure were examined in the same procedure as in the above-described Experiments 4 and 5. The pressure in the decompression chamber 2d during evacuation is -80 kPa.

(Experimental result)
As a result, as shown in the permeability of FIG. 7, all of the three kinds of flowable materials reached the lower surface of the base material by evacuation for 3 minutes. Then, as shown in the result of vacuum water filling in FIG. 7, in the foamed resin composite structure in which the flowable material in which the resin content is 25 vol% and the polymethyl methacrylate resin powder is dispersed in 2.5 or 5.0 vol% is infiltrated, Water oozed slightly on the bottom surface. On the other hand, in the foamed resin composite structure in which the flowable material in which the resin content was 25 vol% and the polymethyl methacrylate resin powder was dispersed by 7.5 vol% was permeated, water did not ooze out from the lower surface even when evacuated for 5 minutes. . In addition, as a result of trying polymethyl methacrylate resin powders having different particle diameters, the particle diameter of the polymethyl methacrylate resin powder is 1/7 or less of the average diameter of the communication holes, that is, 4 μm (= 28 μm / 7) or less. It was found that the polymethyl methacrylate resin powder reached the inside of the base material.

(Conclusion)
From the above experimental results, a flowable material having a viscosity of 2000 mPa · s or less containing 25 vol% resin content and 7.5 vol% polymethyl methacrylate resin powder with respect to a base material having an average diameter of communication holes of 28 μm. It was found that the foamed resin composite structure produced by infiltrating with water has a water-stopping effect up to the inside.
That is, by allowing a fluid material having a volume fraction of the resin content and the polymethyl methacrylate resin powder to be at least 32.5 vol% ≈30 vol% or more into a base material having an average diameter of the communication holes of 28 μm, the inner diameter is increased. It was found that a foamed resin composite structure having a water stop effect can be produced. Further, it has been found that it is desirable to use organic powder having a particle size of 1/7 or less of the average diameter of the communication holes in order to reach the inside of the communication holes.

[Other experiments]
The inventors of the present application also performed the above-described experiments on the base materials having the average diameters of the communication holes of 12 μm and 130 μm. As a result, a foamed resin composite structure having a water stop effect to the inside by infiltrating a flowable material having a volume fraction of the resin content and powder of at least 20 vol% into the base material having an average diameter of the communication holes of 12 μm. It was found that can be manufactured. Further, a foamed resin composite structure having a water-stopping effect to the inside is obtained by infiltrating a fluid material having a volume fraction of the resin and powder of at least 76 vol% into a base material having an average diameter of communication holes of 130 μm. It turns out that it can be manufactured.

(Overall result)
FIG. 8 is a chart summarizing the overall results of Experiments 1 to 6, and FIG. 9 is a graph of the data of FIG. As shown in FIG. 9, as the average diameter of the communication holes of the base material before the fluid material penetrates, the volume fraction of the resin component and the powder necessary for obtaining the water stop effect increases. Of the regions partitioned by the graph, the region above the graph (including the line on the graph) is a region having waterstop, and the region below the graph is a region without waterstop.

Among the areas having water-stopping properties, when the resin content and the volume fraction of the powder become larger than necessary, the viscosity of the fluid material exceeds 2000 mPa · s and does not penetrate into the base material, so the viscosity does not exceed 2000 mPa · s. Thus, it is necessary to select the resin content and the volume ratio of the powder.
That is, according to the average diameter of the 12 to 130 μm communicating holes of the base material, the resin content and the volume ratio of the powder are selected from 20 to 76 vol% so as to enter the region having water blocking properties, and the viscosity is 2000 mPa · s. What is necessary is just to produce a fluid material so that it may become the following.

Further, from the graph shown in FIG. 9, the volume fraction of the resin component and the powder is selected from 18 to 85 vol% so as to enter the region having water-stopping property according to the average diameter of the communication holes of 10 to 150 μm of the base material. In addition, it has been found that the flowable material may be prepared so that the viscosity is 2000 mPa · s or less.
In addition, it is desirable to select a volume fraction that is on the line of the graph in order to minimize the flowable material required to produce a water stop effect and maximize cost effectiveness. In addition, when low molecular weight acrylic acid or the like is used in a dispersive manner, the viscosity may be 2000 mPa · s or less even when the volume fraction of the resin and the powder exceeds 95 vol%. In the range of the resin that can be used, the viscosity can be set to 2000 mPa · s or less by selecting the volume ratio from 18 to 95 vol%. Desirably, when the volume ratio is selected from 18 to 85 vol%, the viscosity is easily set to 2000 mPa · s or less.

  FIG. 10 is an explanatory view of a foamed resin composite structure in which a fluid material has permeated, (a) is a perspective view of the foamed resin composite structure, and (b) is an enlarged view of a region indicated by D in (a). is there. As shown in FIG. 2B, the communication holes formed between the foamed cells 1c are closed by the resin layer 4a. Moreover, the resin layer 4a is also formed in the space | gap which has not formed the communicating hole. This resin layer is formed by drying the fluid material that has penetrated into the gap mainly by capillary action and drying the resin contained in the fluid material. As described above, since the resin layer is formed also in the voids where the communication holes are not formed, the strength of the foamed resin composite structure can be increased.

[Experiment 7]
The inventors of the present application conducted an experiment to examine the relationship between the evacuation time and the penetration depth of the fluid material. FIG. 11 is a chart showing the results of Experiment 7.

(Experiment contents)
The base material used in this experiment is EPS, the expansion ratio is 60 times, the average diameter of the communication holes is 70 μm, the porosity is 3%, and the thickness is 50 mm. Further, as a fluid material, a material obtained by dispersing 10 vol% carbon in acronal S400 having a resin content of 20 vol% was used. In addition, the same apparatus as that used in each experiment described above was used, and the pressure in the decompression chamber 2d was set to −80 kPa. And when 1 minute passed since the pressure of the decompression chamber 2d reached -80 kPa, the base material was cut longitudinally and its cross section was observed, and the depth of the region that was changed to black by carbon was measured. Thereafter, the vacuuming time was changed to 2.5 minutes and 5 minutes, and the same measurement was performed.

(Experimental result)
As shown in FIG. 11, the penetration depths of the flowable material when the vacuuming time was 1 minute, 2.5 minutes, and 5 minutes were 5 mm, 10-20 mm, and 25-30 mm, respectively. That is, the penetration depth of the fluid material increased as the evacuation time increased.

(Conclusion)
It was found that the penetration depth of the flowable material in the base material can be controlled by changing the evacuation time.

[Calculation method of average diameter of communication holes]
Next, a method for calculating the average diameter of the communication holes formed in the base material will be described. Here, description will be made assuming that the communication hole is a capillary tube.

  First, the ratio of the radius of the pre-foamed beads before foaming and the radius of the void formed surrounded by the pre-foamed beads is obtained. FIG. 12 is a schematic view of a pre-foamed bead. Here, it is assumed that the pre-foamed beads are true spheres. As illustrated, the pre-foamed beads 6 are in contact with each other, and a gap 7 is formed in a region surrounded by the three pre-foamed beads 6. Here, it is assumed that the gap 7 is a capillary tube 8 in contact with the three preliminary foam beads 6. A radius of the pre-foamed beads 6 is A, a radius of the capillary 8 is r, an angle formed by a line L1 connecting the centers of the pre-foamed beads 6 and the capillaries 8 and a line L2 connecting the centers of the pre-foamed beads 6 is θ. Then, since θ = 30 °, the following equation (1) is established.

  cos30 ° = A / (A + r) (1)

  Here, substituting cos30 ° ≈0.866 into equation (1) to obtain r,

  r = 0.155A (2)

  That is, the ratio between the radius r of the capillary 8 and the radius A of the pre-foamed beads 6 was obtained. Here, if it is assumed that the expanded beads are expanded while maintaining a true spherical state, the above formula (2) is calculated by the following equation: It can also be applied to the relationship with the radius. Further, since the radius of the capillary 8 surrounded by the pre-expanded beads 6 is increased by the foaming of the pre-expanded beads 6, the above formula (2) can be applied to the relationship between the capillaries before and after the foaming.

  Next, the average diameter of the communication holes formed in the base material actually manufactured by heating, foaming and fusing the preliminary foam beads 6 is determined.

  It is known that the liquid capillary pressure Fc is given by the following formula (3) (cited by Soichi Muroi, published by Kobunsha Co., Ltd., “Polymer Latex for Beginners”).

  Fc = 12.9γ / C (3)

  Here, γ represents the surface tension (N / m) of the liquid, and C represents the radius (m) of the foamed cell forming the capillary tube.

  FIG. 13 is a chart showing the results of a water leak experiment performed on a base material having a foaming ratio of 15 times, and FIG. 14 shows the results of a water leak experiment performed on a base material having a foaming ratio of 60 times. It is a chart. Both base materials are EPS and the thickness is 20 mm. From FIG. 13, in the base material with a foaming ratio of 15 times, water penetrates at a vacuum pressure of −10 kPa. Further, as shown in FIG. 14, in the base material having a foaming magnification of 60 times, water penetrates at a vacuum pressure of −4 kPa.

First, the average diameter of the communication holes formed in the base material having a foaming ratio of 15 is obtained. Since water permeates at -10 kPa (water leakage occurs), the capillary pressure per 1 cm ^{2 of the} base material is 0.1 kPa. Further, the surface tension of water is set to 70 mN / m. Substituting Fc = 0.1 kPa and γ = 70 mN / m into the above equation (3),

0.1 = (12.9 × 70) / (C × 10 ² ) (4)

  When C is obtained from the above equation (4), C = 90.3 μm. Substituting C = 90.3 μm into the above equation (2),

  r = 0.155 × 90.3 μm≈14 μm (5)

  It becomes. Therefore, the average diameter of the communication holes is r × 2 = 14 μm × 2 = 28 μm.

Next, when the average diameter of the communication holes formed in the base material having a foaming ratio of 60 times is obtained, the capillary pressure per 1 cm ^{2 of the} base material is 0. 04 kPa. Further, the surface tension of water is set to 70 mN / m. Substituting Fc = 0.01 kPa and γ = 70 mN / m into the above equation (3),

0.04 = (12.9 × 70) / (C × 10 ² ) (6)

  When C is obtained from the above equation (6), C = 225.75 μm. Then, if C = 225.75 μm is substituted into the above equation (2),

  r = 0.155 × 225.75 μm≈35 μm (7)

  It becomes. Therefore, the average diameter of the communication holes is r × 2 = 35 μm × 2 = 70 μm.

(Effect of embodiment)
(1) If the manufacturing method of the foamed resin composite structure which concerns on the above-mentioned embodiment is implemented, it will be connected by making the fluid material in which resin melt | dissolved or disperse | distributed to the solvent penetrate | infiltrate the communicating hole formed in the base material. Since the holes can be in a non-communication state, it is possible to manufacture a foamed resin composite structure that is lightweight but does not leak water.
For example, if the foamed resin composite structure of the above embodiment is used as a water tray such as a refrigerator or an air conditioner, it is possible to realize a water tray that is lightweight but does not cause water leakage.

(2) Moreover, by allowing the fluid material to penetrate into the base material, it is possible to produce a foamed resin composite structure in which the water leakage effect does not decrease even if the upper surface is damaged.
For example, even when the water pan is damaged during transportation of the water pan, or when a tool such as a screwdriver is dropped and cracked or depressed during installation of the water pan, There is no risk of water leaking.

(3) Furthermore, even when the fusion between the foam cells is incomplete and a gap is formed in the base material, the fluid material penetrates into the gap, so that the fusion is incomplete. The resulting water leak can be eliminated.

(4) When the fluid material that has penetrated into the communication holes formed in the base material is dried and the resin contained in the fluid material is cured, a foamed resin composite structure having high strength can be manufactured. .

(5) By allowing the fluid material in which the powder is dispersed in the solvent to permeate the communicating holes of the base material, the foamed resin composite structure can have the properties of the powder.

(6) Since the volume ratio of the resin and the powder to the solvent is selected from 18 to 95 vol% according to the average diameter of the communication holes formed in the base material of 10 to 150 μm, the flowable material in which the powder is not dispersed The ratio of the resin dissolved or dispersed in the solvent can be reduced as compared with the above.
Therefore, when the material cost of the powder is lower than that of the resin, the production cost of the foamed resin composite structure can be reduced by increasing the amount of the powder.

Second Embodiment
Next explained is the second embodiment of the invention. This embodiment is characterized in that a foamed resin composite structure having conductivity can be manufactured.

[Experiment 8]
The inventors of the present application conducted an experiment to impart conductivity to the fluid material. FIG. 15 is a chart showing the results of Experiment 8.

(Experiment contents)
The flowable material used in this experiment is obtained by dispersing copper powder (MA-C04J) in a vinyl acetate solution (resin content 60 vol%) diluted with methanol. Moreover, four types of fluidity | liquidity materials from which the ratio (vol%) of copper powder and resin differed were created. The viscosity of each flowable material is 2000 mPa · s or less. Then, the prepared fluid material is applied to the upper surface of the base material, the base material is dried to evaporate the evaporation component contained in the fluid material, and a film is formed on the upper surface of the base material by the resin component in which the copper powder is dispersed. Formed. And the electrical resistance of the film | membrane surface formed in the upper surface of the foamed resin composite structure was measured.
Moreover, it attached to one kind of fluid material, said measurement was performed with respect to three same base materials of A, B, and C, and the average value was calculated | required.

(Experimental result)
As shown in FIG. 15, the electrical resistance of the top surface of the foamed resin composite structure is 7.31 × 10 ⁸ Ω to 2.11 × 10 ¹⁰ Ω, and the top surface of the foamed resin composite structure has conductivity. I understood. It was also found that there was no significant difference in the electrical resistance of the film even when the ratio of copper powder and resin was changed.

(Conclusion)
From the above experimental results, by applying a fluid material having a viscosity of 2000 mPa · s or less in which copper powder is dispersed in a diluted vinyl acetate solution to a base material, a foamed resin composite structure having conductivity on the coated surface It was found that can be manufactured. In addition, the fluid material is infiltrated into the base material so that the fluid material remains on the top surface of the base material and dried to form a conductive film on the top surface of the base material. It was considered that a foamed resin composite structure that conducted to the inside of the material could be manufactured. Furthermore, it was considered that a foamed resin composite structure in which the upper and lower surfaces of the base material are conductive can be manufactured by infiltrating the fluid material from the upper surface to the lower surface of the base material.

  The foamed resin composite structure having the above conductivity has various uses. For example, it is an application requiring antistatic. For example, it can be used for a plate or a container on which an electric component is placed in a factory for assembling an electric product or the like. In this case, the conductive film is formed on the surface on which the electrical component is placed, and the conductive film or another portion that is electrically connected to the conductive film is connected (grounded). Thereby, the static electricity of an electrical component can be released to the ground through the conductive film.

  For example, in a line for assembling an electrical product by a robot, the above-mentioned foamed resin composite structure is used for a plate or container on which an electronic component such as an IC chip to be grasped by a robot hand is placed, and the electronic component is placed on the conductive film. Place. According to this, since the static electricity charged in the electronic component can be released from the conductive film to the ground, when the robot hand grasps the electronic component, the electronic component may be destroyed due to the discharge of static electricity. Absent.

[Other Embodiments]
(1) When allowing the fluid material to penetrate into the base material, the fluid material can be left on the upper surface of the base material, and the remaining fluid material can be dried.
According to this manufacturing method, since one surface of the base material can be covered with the resin contained in the flowable material, even if there is a communication hole that is not in a non-communication state, the communication hole The opening on the upper surface can be closed by the remaining resin.
Therefore, the effect of preventing water leakage can be enhanced.

In addition, if the flowable material in which the powder is dispersed remains on the upper surface of the base material, the powder remains on the upper surface of the base material, so that the upper surface of the base material can have a powder property.
Furthermore, the powder attached to the inside of the communication hole and the powder attached to the upper surface of the base material are continuous, so that the powder properties can be imparted to a continuous range from the upper surface to the inside of the communication hole. .

  For example, as in Experiment 7, if a fluid material in which conductive powder such as copper powder is dispersed is infiltrated into the base material, the foam has conductivity on the permeation surface and has a high water leakage prevention effect. A resin composite structure can be manufactured.

(2) A pressurizing device that pressurizes the upper surface of the fluid material disposed on the upper surface of the base material can be used in combination. For example, a lid is disposed in the upper space 2b of the apparatus shown in FIG. 2, and the space formed between the lid and the flowable material is pressurized by sending air with an air pump. According to this method, since the differential pressure between one surface of the base material 1 and the other surface can be increased efficiently, the permeation speed of the flowable material into the base material 1 can be increased. The production efficiency of the resin composite structure can be increased.

(3) The region of the base material that is not desired to be infiltrated with the fluid material may be previously masked with a film or the like. According to this method, the fluid material can be infiltrated into a desired region of the base material.

(4) In the case of using a flowable material in which evaporation of evaporation components is promoted by heating, the base material 1 infiltrated with the flowable material can be heated to promote drying, thereby shortening the production time.

(5) Gold, silver, copper, nickel, palladium, platinum, cobalt, rhodium, iridium, iron, ruthenium, osmium, aluminum, zinc, tin, lead, etc. powdered as conductive powder, these metals Metal powders such as tin oxides, metal oxides such as tin oxide powders, and conductive carbon allotropes such as carbon powders, but conductive metals on the surface of particles such as glass, carbon, mica, and plastics. Those coated with can be used.

(6) Magnetic powder made of ferrite can be used instead of the conductive powder. According to this, a magnetic foamed resin composite structure can be manufactured. Also be in place of ferrite, cobalt ferrite-based magnetic material, metal _{magnetic, CrO 2, γ-Fe 2} O 3, Fe 4 N, also possible to use a powder such as Ba ferrite. Furthermore, by using a mixture of conductive powder and magnetic powder, a foamed resin composite structure having conductivity and magnetism can be produced.

(7) A fluid material in which a powder made of boric acid is dispersed can be allowed to penetrate into the base material. According to this, it is possible to manufacture a foamed resin composite structure having at least the property of avoiding living things. For example, if the foamed resin composite structure is used as a heat insulating material for a building, insects such as termites and cockroaches can be removed or killed. Moreover, if the foamed resin composite structure is used for a float of an offshore structure, shellfish such as barnacles can be prevented from adhering to the float. In addition, since boric acid can penetrate into the base material, even if the surface of the heat insulating material or float is peeled off or chipped, the biological repellent effect can be maintained. In addition, since copper powder also has a biological repellent effect, when a foamed resin composite structure in which copper powder is infiltrated into a base material is applied to a heat insulating material or a float, the same effect as boric acid can be obtained. Can do.

  Alternatively, boric acid or copper powder can be accommodated in a microcapsule, and a fluid material in which a powder obtained by collecting a large number of microcapsules is dispersed can be infiltrated into the base material. For example, as a shell (wall material) constituting the outer shell of the microcapsule, a shell having a property of cracking when the outside air temperature exceeds a predetermined temperature is used, and boric acid is included in the shell as a core (core material). Then, by allowing the flowable material in which the microcapsules are dispersed as a powder to permeate the base material, if the outside air temperature exceeds a predetermined temperature, the microcapsules in the communication holes crack and release boric acid components into the outside air. can do. For example, if the foamed resin composite structure is used as a heat insulating material for a building, insects such as termites and cockroaches can be removed or killed.

  In addition, a shell that decomposes naturally over time can also be used. The “microcapsule” refers to a minute container having a diameter between nanometers and millimeters. Microcapsules include sealed and porous types.

(8) Use of calcium carbonate, talc, clay, magnesium oxide, zinc oxide, carbon black, silicon dioxide, titanium oxide, glass powder, hollow glass balloon, diatomaceous earth, kaolin, perlite, fluorite, bentonite, etc. as the powder it can.

(9) As the fluid material, a solvent-type or dispersion-type resin comprising at least one of acrylic, synthetic rubber, vinyl acetate, ethylene, epoxy, and urethane can be used. For example, acrylic solvent-type or dispersion-type resins include butyl acrylate-methyl methacrylate-acrylic acid copolymer, ethyl acrylate-styrene-acrylamide copolymer, 2-ethylhexyl acrylate-methacrylic acid-acrylic acid copolymer. A polymer or the like can be used. As the synthetic rubber solvent type or dispersion type resin, styrene-butadiene latex, styrene-acrylonitrile-butadiene latex, polybutadiene latex, or the like can be used. In addition, vinyl acetate, solvent-type or dispersion-type resins include polyvinyl acetate, vinyl acetate-ethyl acrylate copolymer, vinyl acetate-methyl methacrylate copolymer, vinyl acetate-veova copolymer, polyvinyl Alcohol or the like can be used. Also, polyethylene emulsion, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-acrylic acid copolymer, ethylene-acrylonitrile-vinyl acetate copolymer, etc. should be used as ethylene-based solvent-type or dispersion-type resins. Can do. In addition, epoxy, butyl acrylate-glycidyl methacrylate-acrylamide copolymer, or the like can be used as an epoxy-based solvent-type or dispersion-type resin. In addition, polyurethane, urethane-modified acrylic acid-methacrylic acid copolymer, or the like can be used as the urethane-based solvent-type or dispersion-type resin.
Furthermore, various resin aqueous emulsions obtained by dispersing each of the above resins in water can be used. For example, an aqueous resin emulsion such as an epoxy resin aqueous emulsion, an ethylene-acrylic acid copolymer resin aqueous emulsion, a modified aliphatic polyamine resin aqueous emulsion, and a biodegradable resin aqueous emulsion can be used.

(10) The fluid material can also be colored. As the colorant, a general pigment or dye can be used. Examples of the pigment include those used as coloring materials and fillers, such as titanium oxide, calcium carbonate, dolomite, cinnamon sand, iron oxide, carbon black, cyanine pigment, and quinacrine pigment. Examples of the dye include azo dyes, anthraquinone dyes, indigoid dyes, and stilbene dyes.

Furthermore, metal powders such as aluminum flakes, nickel powder, gold powder, silver powder, copper powder, and titanium oxide may be used as the colorant.
By coloring the epoxy resin with these colorants, the color and pattern of the foamed resin composite structure can be changed.

(11) The foamed resin raw material for forming the base material 1 is not particularly limited as long as it is foamed at a specific foaming temperature, but is impregnated with a thermoplastic material as a main material and gas or liquid as a foaming agent. Although the thing made to use or the thing containing a thermally decomposable foaming agent is used suitably, what contains both may be used. The thermoplastic substance may be cross-linked.

Commercially available polystyrene foam beads, polyethylene foam beads, polypropylene foam beads, etc. may be used as the thermoplastic resin as the main material and gas or liquid impregnated as a foaming agent, butane, pentane, It may be impregnated with hydrocarbon such as chlorofluorocarbon, water, CO ₂ and N ₂ . Moreover, as a thing containing a thermally decomposable foaming agent, you may use suitably preparing from the thermally decomposable foaming agent and thermoplastic material which are shown below. In this thermally decomposable foaming agent and thermoplastic material, the decomposition temperature of the foaming agent is preferably higher than the plasticizing temperature of the thermoplastic material, and the decomposition temperature of the foaming agent and the plasticizing temperature of the thermoplastic material are almost equal. It is further preferable that the foamed material can be foamed neatly.

  The main material of the foam material is not particularly limited as long as it is a substance that is softened by heating, and a group of synthetic plastic materials known as thermoplastic resins are preferably used. For example, poly (styrene); olefin-based resins such as poly (ethylene) and poly (propylene); poly (vinylidene chloride), poly (vinyl chloride), ethylene-tetrafluoroethylene copolymer, poly (vinylidene fushiide), Poly (vinyl fluoride), poly (chlorotrifluoroethylene), fluorinated ethylene propylene copolymer, poly (tetrafluoroethylene), chlorinated poly (vinyl chloride), chlorinated poly (ethylene), chlorinated poly ( Halogenated resins such as propylene); polyamides such as nylon 6, nylon 66, nylon 610, nylon 612, nylon 11, nylon 12, nylon MXD6, nylon 46, N-methoxymethylated poly (amide), aminopoly (acrylamide); Styrene-isoprene-styrene block copolymer, Tylene-butadiene-styrene block copolymer, styrene- (ethylene-butylene) -styrene block copolymer, polypropylene-EPDM, polyethylene-EPDM, isobutylene-oleic anhydride copolymer, acrylonitrile-acrylate-styrene copolymer Acrylonitrile-ethylene-styrene copolymer, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-vinyl chloride-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer, Copolymers such as ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer; ionomer, ketone resin, poly (acrylic acid), poly (acrylic acid ester), poly (Methacrylic acid ester), poly (vinyl propionate), poly (acetal), poly (amidoimide), poly (arylate), thermoplastic poly (imide), poly (ether imide), poly (ether ethertone), poly ( Ethylene terephthalate), polycarbonate, poly (vinyl acetate), poly (sulfone), poly (ethersulfone), poly (aminosulfone), poly (paramethylstyrene), poly (allylamine), poly (vinyl alcohol), poly (vinyl ether) ), Poly (vinyl butyral), poly (phenylene oxide), poly (phenylene sulfide), poly (butadiene), poly (butylene terephthalate), poly (methyl pentene), poly (methyl methacrylate), liquid crystal polymer, poly (urethane) Etc. It is possible. A polylactic acid resin can also be used. In addition, a modified product or a crosslinked product of the above polymer may be used as appropriate, or a copolymer obtained by combining these may be used. Furthermore, these thermoplastic resins may be used independently and may use 2 or more types together.

The thermally decomposable foaming agent to be kneaded with the foamed resin raw material is not particularly limited as long as it is a commonly used thermal decomposable foaming agent, and is selected according to the plasticizing temperature of the main material of the foamed resin raw material. It is.
Examples of such thermally decomposable blowing agents include azo compounds such as azodicarbonamide (ADCA), azobisisobutyronitrile (AIBN), azocyclohexylnitrile, diazoaminobenzene, azodicarbonamide ester; Nitroso compounds such as methylenetetramine (DPT); p-toluenesulfonyl hydrazide (TSH), benzenesulfonyl hydrazide (BSH), p, p′-oxybisbenzenesulfonyl hydrazide, diphenylsulfone-3,3′-disulfonyl hydrazide, etc. Sulfonyl hydrazide compounds; azide compounds such as 4,4′-diphenyldisulfonyl azide, p-toluenesulfoazide; p-toluenesulfo semicarbazide, trihydrazinotriazine, sodium hydrogen carbonate, ammonium carbonate, ammonium nitrite, etc. it can Furthermore, these thermally decomposable foaming agents may be used alone or in combination of two or more.

  In addition to these foaming agents, various additives may be added to the foamed resin raw material for the purpose of improving molding characteristics. Additives include metal soaps such as zinc stearate and calcium stearate, and inorganic salts such as zinc zinc nitrate.

  The foaming aid varies depending on the type of resin, foaming agent, and aid used, but it is usually preferred to add at a ratio of about 0.1 to 2.0 parts by weight with respect to 100 parts by weight of the thermoplastic resin. This is because the effect is small when the addition amount is 0.1 parts by weight or less, and the effect tends to be saturated when the amount is 2.0 parts by weight or more.

  The size of the expandable beads is preferably 0.3 to 5 mm. Here, the size of the expandable beads is the average diameter when the expandable beads are substantially spherical. Further, in the case of flat or strand-shaped ones, the size of the expandable bead refers to the smallest width, and hereinafter, the size of the expandable bead is assumed to follow this example. The reason why foamed beads with a size of 0.3 mm to 5 mm are suitably used is that the foamable beads are easy to manufacture, the surface area of the foamable beads, and softening unevenness due to heat transfer delay is less likely to occur. This is the result of the trade-off. It is possible to use beads smaller than 0.3 mm, but in this case, the total surface area of the beads increases, so that the area of the interface where the final foam cell contacts increases, forming a thin-walled rigid cell wall. Much more material to do. Therefore, although the compressive strength is increased, the effect of reducing the weight is reduced.

If a mechanism for generating heat from the inside of the expandable beads is used in combination, expandable beads having a diameter larger than 5 mm can also be used. As a mechanism for causing heat generation from the inside of the expandable bead, for example, electromagnetic induction in a high frequency electromagnetic field environment by mixing metal powder into the expandable bead can be used.
In order to obtain a foamed resin composite structure having a homogeneous foamed cell structure, it is desirable that the sizes of the expandable beads are substantially uniform. However, they do not have to be strictly aligned. In addition, since the foamed cell membrane can have a specific three-dimensional structure by intentionally distributing the size of the expandable beads, different sizes of expandable beads may be used in combination.

  Further, the foamed material may be a material in which a foamed material such as pre-foamed beads or a foamed product is impregnated with gas under high pressure. Further, it may be a foamed chip-shaped or straw-shaped material or a crushed foam, and the base material 1 may be formed by condensing the material and heat-sealing it in a mold. .

It is explanatory drawing of a base material, (a) is a perspective view of a base material, (b) is an enlarged view of the area | region D shown to (a). It is a longitudinal cross-sectional view of the state in which the base material 1 and the flowable material 4 are set in the apparatus. It is a graph which shows the result of the experiment 1 with respect to the base material whose expansion ratio is 60 times, the average diameter of a communicating hole is 70 micrometers, and the porosity is 3%. 6 is a chart summarizing the results of Experiments 2 and 3. 6 is a chart summarizing the results of Experiment 4. 10 is a chart summarizing the results of Experiment 5. 10 is a chart summarizing the results of Experiment 6. It is the table | surface which put together the comprehensive result of Experiment 1-6. FIG. 9 is a graph of the data of FIG. It is explanatory drawing of the foamed resin composite structure which the fluid material osmose | permeated, (a) is a perspective view of a foamed resin composite structure, (b) is an enlarged view of the area | region shown by D in (a). 10 is a chart showing the results of Experiment 7. It is a schematic diagram of a pre-foaming bead. It is a graph which shows the result of the water leak experiment performed with respect to the base material of 15 times of foaming magnifications. It is a graph which shows the result of the water leak experiment performed with respect to the base material of 60 times of expansion ratios. 10 is a chart showing the results of Experiment 8. It is a schematic diagram of the foamed resin molding machine described as a prior art in the patent gazette.

Explanation of symbols

1. Base material, 1a, one surface, 1b, other surface, 1c, foam cell, 1d, communication hole,
2 .. Container, 2d .. Decompression chamber, 2e .. Vent, 3 .. Decompression device, 4 .. Fluid material, 4a .. Resin layer, 5 .. Foamed resin composite structure.

Claims (9)

A closed cell structure is formed by fusing adjacent foam cells, and there is a communication hole communicating from one surface to the other by communicating between the closed cells, and the communication hole A base material having an average diameter of 10 to 150 μm;
A flowable material in which the resin is dissolved or dispersed in a solvent and the viscosity is 2000 mPa · s or less;
Preparing a differential pressure generating device that generates a differential pressure between the one surface and the other surface so that the pressure on the other surface is lower than the one surface;
A first step of disposing the flowable material on the one surface;
By generating a differential pressure between the one surface and the other surface by the differential pressure generating device, the flowable material disposed on the one surface is allowed to permeate the communication hole, thereby forming the communication hole. A second step of making the communication state non-communication,
The volume ratio of the resin is selected from 18 to 95 vol% according to the average diameter of the communication holes. Powder is dispersed in the solvent,
2. The method for producing a foamed resin composite structure according to claim 1, wherein a volume ratio of the resin and powder to the solvent is selected from 18 to 95 vol% according to an average diameter of the communication holes.   The method for producing a foamed resin composite structure according to claim 2, wherein the powder is at least one of a conductive powder and a magnetic powder.   The method for producing a foamed resin composite structure according to claim 3, wherein the conductive powder is a powder comprising at least copper.   The method for producing a foamed resin composite structure according to claim 3 or 4, wherein the magnetic powder is a powder comprising at least ferrite. The method for producing a foamed resin composite structure according to claim 2 , wherein the powder is a powder comprising at least boric acid. The second step includes
The method for producing a foamed resin composite structure according to any one of claims 1 to 6, wherein the flowable material is left so as to remain on the one surface.   The fluid material is a solvent-type or dispersion-type resin composed of at least one of acrylic, synthetic rubber, vinyl acetate, ethylene, epoxy, and urethane. Item 8. A method for producing a foamed resin composite structure according to any one of Items 7 to 9.   The method for producing a foamed resin composite structure according to claim 8, wherein the fluid material is an aqueous resin emulsion.

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