JP6439971B2 - Manufacturing method of foamed resin, manufacturing method of pulverized product, manufacturing method of water absorbing material, and manufacturing method of sound absorbing material - Google Patents

Description

  The present invention relates to a foamed resin, and more particularly to a foamed resin subjected to a decomposition treatment using microorganisms, and a pulverized product, a water absorbing material and a sound absorbing material using the same.

  Polyurethane is a polymer having a urethane bond and is also called urethane resin. Polyurethane is gradually decomposed under the influence of moisture hydrolysis, nitrogen oxides (NOx) in the air, salinity, ultraviolet rays, heat, microorganisms, etc., and produces compounds harmful to human bodies and aquatic organisms. Since the leaked polyurethane may cause enormous environmental pollution, it is usually collected by taking preventive measures such as adsorbing it to earth and sand, surrounding it, etc. and sealing it in a container. A recycling system has also been developed for polyurethane, but about 40% of waste polyurethane is still landfilled.

  The inventors found a novel microorganism having adsorption ability and resolution for urethane from soil and filed a patent application (Patent Document 1). The microorganism was found to be a novel actinomycete belonging to the genus Streptomyces from mycological properties and DNA analysis. Since this microorganism has an adsorptivity to urethane, it can bind and agglomerate urethane particles dispersed in water to effectively remove (adsorb and purify) urethane.

JP 2010-220610 A

  Although the microorganism described in Patent Document 1 has an adsorption ability and resolution for urethane, it is necessary to further improve the decomposition rate of urethane for industrial use, and there is room for improvement in that respect.

By the way, as urethane, although it is an elastic body and a material with high viscoelasticity like soft polyurethane, it was very difficult to pulverize such polyurethane at room temperature. In particular, polyurethane having independent bubbles has high elasticity and mechanical strength, and is more difficult to process than a foam in which bubbles are communicated.
As a method for powderizing such urethane foam, there is known a method of pulverizing after solidifying by freezing using liquid nitrogen. However, such a method is not practical because the equipment becomes large and the running cost increases.

  Then, this invention provides the processing method for making it easy to grind foamed resin like foaming urethane which has an independent cell, and aims at providing the novel foamed resin obtained by the said processing method.

  As a result of intensive investigations by the present inventors to solve the above problems, it has been found that it is effective to connect at least some of the bubbles by allowing microorganisms to act on the foamed resin having independent bubbles. The present invention has been completed. That is, the present invention adopts the following configuration.

(1) A method for producing a foamed resin having a structure in which at least some of the independent bubbles are linked by the action of microorganisms ,
Treating the foamed resin with an unsaturated fatty acid;
A step of causing microorganisms to act on the foamed resin treated with the unsaturated fatty acid;
Including
The foamed resin is foamed urethane,
The microorganism is a microorganism belonging to the genus Streptomyces having urethane decomposability,
Manufacturing method of foamed resin .
(2) having a step of pulverizing the foamed resin obtained by the method for producing a foamed resin described in (1 ) above,
A method for producing a pulverized product .
(3) A method for producing a water-absorbing material comprising a pulverized product of foamed resin having a structure in which at least some of the independent bubbles are linked by the action of microorganisms,
Treating the foamed resin with an unsaturated fatty acid;
A step of causing microorganisms to act on the foamed resin treated with the unsaturated fatty acid;
Crushing the foamed resin after allowing the microorganisms to act;
Including
The foamed resin is foamed urethane,
The microorganism is a microorganism belonging to the genus Streptomyces having urethane decomposability,
Manufacturing method of water absorbing material .
(4) A method for producing a sound-absorbing material comprising a foamed resin pulverized product having a structure in which at least some independent bubbles are connected by the action of microorganisms,
Treating the foamed resin with an unsaturated fatty acid;
A step of causing microorganisms to act on the foamed resin treated with the unsaturated fatty acid;
Crushing the foamed resin after allowing the microorganisms to act;
Including
The foamed resin is foamed urethane,
The microorganism is a microorganism belonging to the genus Streptomyces having urethane decomposability,
A method for producing a sound absorbing material .

  According to the present invention, it is possible to provide a foamed resin that can be easily pulverized and is excellent in water absorption and sound absorption.

It is the microscope picture which observed the mode of the foaming cell before and after making microorganisms act on foaming urethane. It is a photograph showing the result of having observed the state of the foaming cell after making microorganisms act on foaming urethane with an electron microscope. It is a photograph which shows the external appearance of the ground material of this invention. It is the microscope picture which observed the mode of the foaming cell of the foaming resin which changed the period when a microorganisms act. It is a graph showing the result of the water absorption measured in the Example. It is a graph showing the change of the moisture content measured in the Example. It is a graph showing the result of the sound absorption rate measured in the Example. It is a graph showing the result of the sound absorption rate measured in the Example.

[Foamed resin]
The foamed resin according to the present invention has a structure in which at least some of the foamed resin having independent bubbles are connected to each other by the action of microorganisms. As a result, a foamed resin having characteristics as a new material having both characteristics of a foamed resin having independent bubbles and a foamed resin having continuous bubbles can be obtained.
The foamed resin according to the present invention can be obtained by allowing a microorganism having resolution to act on a foamed resin having independent bubbles. By allowing microorganisms having resolution to act on the foamed resin, a microcavity of about several microns (about 1 μm to 5 μm) is formed on the wall surface of the independent bubbles so that the adjacent bubbles are connected to each other. Become. By proceeding such decomposition action by microorganisms, a foamed resin in which independent bubbles are connected by a fine cavity is obtained.

The foamed resin according to the present invention has a structure of a foamed resin having independent bubbles as a basic skeleton, but the bubbles are connected by a fine cavity due to the action of microorganisms. The new cell structure due to the formation of the fine cavities makes it possible to exhibit both the characteristics of the foamed resin having independent bubbles and the characteristics of the foamed resin having continuous bubbles.
Specifically, the foamed resin according to the present invention can be finely powdered (particle size is 300 μm or less) at room temperature while having elasticity. Such a powdered pulverized product has elasticity, is effective in absorbing sound energy, and has excellent sound absorption characteristics.
Further, the foamed resin according to the present invention has the characteristics that the water absorption is greatly improved due to the formation of the fine cavities, and further, the water once absorbed is hardly released, and the water retention is excellent. This is presumably because the water absorbed by the surface tension of water is retained as it is while the water is absorbed by the bubble portions connected by capillary action.

The foamed resin is not particularly limited, and examples of the synthetic resin material include polyurethane foam, polystyrene foam, polyethylene foam (PEF), polypropylene foam (PPF), and phenol foam. Examples of the material include carbonized cork.
Moreover, the said microorganisms should just be microorganisms which have resolution | decomposability with respect to resin which comprises a foamed resin. For example, when the resin is urethane, the microorganism is not particularly limited as long as it is a microorganism having urethane decomposability, but is preferably a microorganism having a sufficiently high ability to decompose urethane. As such microorganisms, the present inventors have discovered microorganisms belonging to the genus Streptomyces. Also in the present invention, this microorganism (see Patent Document 1) can be preferably used.

  As an example of the microorganism having the urethane decomposing ability, a microorganism (Streptomyces C13a) specified by the accession number FERM P-21770 can be given. On February 12, 2009, the microorganism was deposited at the Patent Organism Depositary (National Institute of Advanced Industrial Science and Technology, Tsukuba City 1-1-1 Tsukuba Center Chuo No. 6) with the above accession number. ing. In addition, as long as it has the urethane adsorption | suction and resolution | decomposability equivalent to this, the mutant of the said microorganism can also be used preferably. Specifically, for example, S.M. albogriseolus (NBRC12834), S. alboliseolus. thermolyticus (NBRC14269), and S. Viridodiastaticus (NBRC13106) or the like can be preferably used.

  In addition, although the foamed resin of this invention can be utilized as a raw material which has a new characteristic as mentioned above, it can also be reused as a raw material at the time of synthesize | combining a polyurethane. In this case, it is possible to adopt an aspect such as adding a pulverized foamed resin of the present invention to a urethane raw material polyol.

[Method for producing foamed resin]
The foamed resin according to the present invention can be produced by allowing a microorganism having a resolution to act on a foamed resin having independent bubbles to the resin constituting the foamed resin. As described above, the foamed resin can include, for example, polyurethane foam, polystyrene foam, polyethylene foam (PEF), polypropylene foam (PPF), phenol foam, and the like as synthetic resin materials, and carbonized as a natural material. Cork etc. can be mentioned. Moreover, the said microorganisms should just be microorganisms which have resolution | decomposability with respect to the resin which comprises a foamed resin, and when the resin is polyurethane, the above-mentioned microorganisms which have urethane resolution can be utilized.

In the foamed resin having independent bubbles as a starting material, the size of the bubbles is not particularly limited, and various types can be used. For example, a foamed resin having an independent bubble particle size of about 10 μm to 300 μm can be used. Generally, the structure of a foamed resin is determined by a foaming agent added at the time of molding. In the present invention, the foamed resin used as the starting material does not need to be completely independent of all the bubbles, and may include a portion where the bubbles are connected to each other.
In the following, the resin constituting the foamed resin is polyurethane, and the foamed resin of the present invention is produced by taking as an example the case where it is a microorganism specified by the accession number FERM P-21770 as a microorganism having a resolution for the polyurethane. A method will be described.

  As the urethane foam having independent bubbles, for example, waste materials such as a bed, an automobile seat, and a steering can be used. These waste materials have high physical strength and are difficult to pulverize, but by processing them into a foamed resin having a structure in which at least some of the independent bubbles communicate with each other as in the present invention. It becomes possible to make it easy to grind.

In the case of producing the foamed resin according to the present invention using the foamed urethane having independent bubbles, the step of treating the material to be treated containing the foamed urethane having independent bubbles with the unsaturated fatty acid, and the unsaturated fatty acid. It is preferable to perform a step of allowing a microorganism belonging to the genus Streptomyces having urethane resolution to act on the treated material.
The foamed resin according to the present invention can be produced by allowing microorganisms having urethane resolution to act on foamed urethane having independent bubbles, but in that case, by treating the foamed urethane with an unsaturated fatty acid. The present inventors have found that the action of decomposing urethane by microorganisms dramatically increases.

The unsaturated fatty acid may be an unsaturated fatty acid containing one or more double bonds in the structure. In addition, the unsaturated fatty acid is preferably liquid under the use temperature condition of room temperature because the material to be treated can be easily treated. In this case, room temperature means, for example, about 0 ° C to 35 ° C.
Examples of the unsaturated fatty acid include oleic acid, linoleic acid, palmitoleic acid, α-linolenic acid, γ-linolenic acid, arachidonic acid, docosahexaenoic acid (DHA), erucic acid, succinic acid, Linderic acid, palmitoleic acid, and elaidin. An acid etc. are mentioned. These unsaturated fatty acids may be used alone or in a combination of two or more.
The unsaturated fatty acid is preferably an unsaturated fatty acid containing one unsaturated bond rather than one containing two or more double bonds in the structure.
Among the above unsaturated fatty acids, oleic acid, erucic acid, and linoleic acid can be particularly preferably used.

  Examples of the method of treating the material to be treated with the unsaturated fatty acid include a method of immersing the material to be treated in the unsaturated fatty acid or applying an unsaturated fatty acid to the material to be treated. In particular, the method of immersing the material to be treated in the unsaturated fatty acid is preferable because the unsaturated fatty acid can act on the entire material to be treated and is a simple method.

  The longer the time for treating the material to be treated with the unsaturated fatty acid, the better. However, the effect can be obtained even for several seconds. In order to acquire a higher effect, it is preferable to process for 1 hour or more. In addition, when the method for decomposing urethane of the present invention is used industrially, it is disadvantageous to perform the treatment for an excessively long time. From these viewpoints, the time for treating the material to be treated with the unsaturated fatty acid is more preferably 8 hours or more and 24 hours or less.

  The temperature at the time of processing a to-be-processed material with an unsaturated fatty acid is not specifically limited, It is preferable to carry out in the temperature range in which an unsaturated fatty acid hold | maintains a liquid. For example, when oleic acid or linoleic acid is used as the unsaturated fatty acid, the treatment may be performed at about 30 ° C.

In the step of treating the material to be treated with the unsaturated fatty acid, the unsaturated fatty acid and alcohol are preferably mixed and used. In general, unsaturated fatty acids have a high viscosity and are difficult to handle. However, when mixed with alcohol, the viscosity decreases and the handling is improved. Moreover, when the viscosity of the treatment liquid in which the unsaturated fatty acid and the alcohol are mixed is lowered, it is possible to suppress the phenomenon that the materials to be treated immersed in the treatment liquid are aggregated and fixed. As a result, stable processing with little variation is possible. Furthermore, since the treatment liquid having a low viscosity penetrates quickly into the material to be treated, not only the surface of the material to be treated but also the entire treatment can be performed.
Thus, by making the said processing liquid which mixed the unsaturated fatty acid and alcohol acted on a to-be-processed material, physical properties, such as a breaking stress and elongation of a to-be-processed material, can be reduced significantly. When microorganisms are allowed to act on a material to be treated, the material to be treated is crushed as small as possible rather than a large lump so that the decomposition efficiency of microorganisms is improved. For this reason, when the physical properties such as the breaking stress and elongation of the material to be treated are reduced as described above, it is preferable that the material to be treated is easily crushed.

  In addition, by causing microorganisms to act on the material to be treated that is sufficiently treated not only on the surface but also on the inside with the unsaturated fatty acid, the decomposition can be uniformly promoted to the inside of the material to be treated. Thus, when decomposition | disassembly has fully progressed to the inside of a to-be-processed material, it will become easy to grind | pulverize the to-be-processed material after making microorganisms act, and to make it into a powder form.

  Moreover, the effect which wash | cleans the surface of a to-be-processed material is also acquired by using the processing liquid which mixed unsaturated fatty acid and alcohol. Silicone release agents and acrylic urethane-based barrier coats may adhere to the surface of the treated material containing urethane foam, and these deposits reduce the decomposition efficiency of the treated material by microorganisms. Is. In the case of such a material to be treated, by using a treatment liquid in which the unsaturated fatty acid and the alcohol are mixed, the silicone-based release agent and the acrylic urethane-based barrier coat adhered to the surface of the material to be treated are removed. It is possible to prevent degradation of the decomposition efficiency of the material to be treated by microorganisms.

  The type of the alcohol is not particularly limited, but preferably has a lower viscosity than the unsaturated fatty acid and has sufficient solubility affinity for the unsaturated fatty acid. Moreover, the thing with the high cleaning effect of the said silicone type mold release agent or an acryl urethane type barrier coat is preferable. From the standpoint of availability, it is preferable to use a lower alcohol. Specifically, any one selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-butanol and 2-methyl-2-butanol Alternatively, a mixture of two or more kinds can be preferably used.

  The mixing ratio of the unsaturated fatty acid and the alcohol is preferably 1: 9 to 7: 3 in terms of volume ratio in consideration of reducing the adsorption amount of the unsaturated fatty acid as much as possible in consideration of the post-process. 7-6: 4 is more preferable, and 5: 5 is still more preferable.

  When the alcohol is used for the purpose of cleaning the surface of the material to be treated, the material to be treated may be washed with alcohol before the material to be treated is treated with the unsaturated fatty acid. In this case, the material to be treated may be washed by immersing the material in alcohol and shaken, and then the unsaturated fatty acid or a mixture of the unsaturated fatty acid and alcohol may be allowed to act on the material to be treated.

  The microorganism that acts on the material to be treated is not particularly limited as long as it is a microorganism having urethane decomposability, but is preferably a microorganism having a sufficiently high ability to decompose urethane. As such microorganisms, the present inventors have discovered microorganisms belonging to the genus Streptomyces. Also in the present invention, this microorganism (see Patent Document 1) can be preferably used.

As an example of the microorganism that can be used in the present invention, a microorganism (Streptomyces C13a) specified by accession number FERM P-21770 can be mentioned. On February 12, 2009, the microorganism was deposited at the Patent Organism Depositary (National Institute of Advanced Industrial Science and Technology, Tsukuba City 1-1-1 Tsukuba Center Chuo No. 6) with the above accession number. ing. Note that mutant strains of the above microorganisms can also be preferably used in the present invention as long as they have urethane adsorption and resolution equivalent to this. Specifically, for example, S.M. albogriseolus (NBRC12834), S. alboliseolus. thermolyticus (NBRC14269), and S. Viridodiastaticus (NBRC13106) or the like can be preferably used.
Hereinafter, the method for decomposing urethane according to the present invention will be described by taking as an example the case of using a microorganism specified by the accession number FERM P-21770.

The method for causing the microorganism to act on the material to be treated is not particularly limited as long as the material to be treated and the microorganism are in contact with each other. For example, there is a method in which a material to be treated is added to a culture solution in which the microorganism is cultured and culture of the microorganism is continued. In addition, a to-be-processed material may be added to the culture solution which does not contain microorganisms, and the said microorganisms may be newly inoculated here.
Since the microorganism belonging to the genus Streptomyces is a soil fungus, it has a strong growth potential at a relatively low temperature, a simple medium of carbon and inorganic salts, and is cultured by a simple method (general shaking culture). it can. In addition, it can survive in harsh environments due to the formation of spores, and generally produces antibacterial compounds, and thus has the advantage of high inhabitability even in a heterogeneous microbial environment. The medium and culture method for culturing the microorganism may be performed according to the description in Patent Document 1.

The longer the time for which the microorganisms are allowed to act on the material to be treated, the better. However, the urethane may be sufficiently decomposed in consideration of the content of urethane in the material to be treated and the amount of microorganisms to act.
The temperature at which the microorganisms are allowed to act on the material to be treated may be a temperature suitable for the growth of microorganisms or the decomposition of urethane, for example, 26 to 45 ° C, preferably around 30 to 45 ° C.

In the method for decomposing urethane according to the present invention, the microorganism is allowed to act while the material to be treated is treated with the unsaturated fatty acid, that is, the microorganism is allowed to act on the material to be treated in the presence of the unsaturated fatty acid. Is preferred. For example, the microorganism may be cultured by adding the unsaturated fatty acid and the material to be treated to the culture solution of the microorganism. The concentration of the unsaturated fatty acid at this time may be 0.1% (W / V) or less.
By doing in this way, it becomes possible to decompose | disassemble the urethane contained in a to-be-processed material by a simpler method.

[Crushed product]
The pulverized product according to the present invention can be obtained by pulverizing the foamed resin according to the present invention. Since the foamed resin according to the present invention has microscopic voids of bubbles, many starting points that break when pulverized appear. For this reason, even if it is an elastic body, it is possible to grind well even at room temperature by using a centrifugal grinder. For example, a finely pulverized product having an average particle size of 300 μm or less can be obtained.
Conventionally, it is very difficult to pulverize a foamed resin having independent bubbles, and when it is freeze-solidified and pulverized, it costs nearly 100,000 yen per kg and is not practical. On the other hand, the foamed resin of the present invention can be easily pulverized even at room temperature, and can be pulverized very inexpensively at about several hundred yen per kg.
In addition, the method of grind | pulverizing the foamed resin which concerns on this invention is not specifically limited, You may grind | pulverize by another method. In addition, the particle size of the pulverized product may be appropriately selected according to the purpose of using the pulverized product. For example, when the pulverized material is used as a material for synthesizing a new urethane material, the average particle diameter may be about 50 μm to 500 μm. When the pulverized product is used as a water absorbing material, the average particle size may be about 50 μm to 5000 μm, and when used as a sound absorbing material, the average particle size may be about 50 μm to 5000 μm. That's fine. In addition, when using the pulverized product as a water-absorbing material or a sound-absorbing material, characteristics change depending on the size of the particle size of the pulverized product. There is.

[Water absorbing material]
The pulverized product according to the present invention can be preferably used as a water absorbing material.
In general, a foamed resin having independent bubbles has the bubbles partitioned by walls and contains air, and gas and liquid cannot pass through the inside. On the other hand, since the foamed resin according to the present invention has a structure in which bubbles are connected by a microcavity of about several microns (1 μm to 5 μm), it can absorb liquid such as moisture. At this time, a liquid such as moisture is absorbed into the bubbles connected by capillary action. And the absorbed liquid such as moisture becomes difficult to be released by the surface tension. Thus, the foamed resin according to the present invention has an effect of having a high water absorption rate and excellent water retention.
The water-absorbing material according to the present invention uses a pulverized product obtained by pulverizing the foamed resin according to the present invention having a high water absorption rate and excellent water retention as described above. Such a water absorbing material can be used, for example, as a planter for plant growth or a humidity control material. From the effect of excellent water retention, it can be preferably used for plant growth, and can also be applied to the greening of rooftops of buildings.

[Sound absorbing material]
The pulverized material according to the present invention can be preferably used as a sound absorbing material.
In general, the sound absorbing effect of the sound absorbing material is exhibited by absorbing sound vibration energy and converting it into thermal energy. In the pulverized product obtained by pulverizing the foamed resin according to the present invention, the pulverized product itself is elastic and easily absorbs energy. It is considered that an excellent sound absorbing effect is exhibited by the synergistic effect of the two phenomena.
The sound absorbing material according to the present invention can be preferably used as a sound absorbing heat insulating material for a refrigerator, a vending machine, or the like.

As the water absorbing material and sound absorbing material according to the present invention, the foamed resin according to the present invention and the pulverized material according to the present invention can be used as they are, or these can be molded into a desired shape and used. Is also possible. When processing into a desired shape, for example, a method such as adding a binder such as an isocyanate-based prepolymer to the foamed resin or the pulverized product and performing hot press molding while spraying steam may be used.
In addition, chip urethane is known as a reproduction of the conventional pulverized foam resin. However, the use of pulverized urethane is so large that it cannot be used to mold complicated shapes and has limited applications. It was. On the other hand, since the foamed resin according to the present invention can be finely pulverized, it can be processed into a complicated shape by using a pulverized pulverized material, and can be used in various fields. .

  Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

[Example 1]
(Material to be treated)
A material obtained by pulverizing waste urethane foam used for automobile steering to a size of about 5 mm square was used as a material to be treated.
(Unsaturated fatty acid)
As the unsaturated fatty acid, oleic acid (manufactured by Wako Pure Chemical Industries, Ltd., grade: Wako first grade) was used.
(Microorganism)
A microorganism (strain: C13a) specified by the accession number FERM P-21770 was used as a microorganism having urethane adsorption / degradability.

(Culture medium)
As a medium for culturing the microorganism, YES-G medium prepared as follows was used.
A KH ₂ PO ₄ solution and a Na ₂ HPO ₄ solution having concentrations shown in Table 1 below were prepared, and 10 mL and 40 mL were mixed to prepare Solution A. Other Solution B, Solution C, and Solution D were solutions having compositions as shown in Table 1 below. The prepared Solutions A to D were sterilized under the conditions of 121 ° C. and 20 minutes.
A 3 L Erlenmeyer flask was mixed with 20 mL of Solution A, 4.0 g of gelatin, 970 mL of distilled water, and 0.5 g of (NH ₄ ) ₂ SO ₄ , and sterilized at 121 ° C. for 20 minutes. After cooling, 10 mL of Solution B, 0.1 mL of Solution C (10-fold concentration), and 2 mL of Solution D were added to the 3 L Erlenmeyer flask to prepare a YES-G medium.

-Process of treating material to be treated with unsaturated fatty acid-
A solution prepared by diluting oleic acid with 99% ethanol to a concentration of 10% (W / W) was prepared and added to a 100 mL Erlenmeyer flask.
About 4 to 5 g of the material to be treated was placed in the 100 mL Erlenmeyer flask, the material to be treated was completely immersed, covered with aluminum foil, and treated at room temperature for 1 hour.
After the treatment time had elapsed, the inside of the Erlenmeyer flask was washed with tap water and distilled water, and further distilled water was added and washed with ultrasonic waves. The material to be treated was taken out from the Erlenmeyer flask and further washed with distilled water. Thereafter, it was dried overnight at 40 ° C. and sterilized under the conditions of 121 ° C. and 20 minutes.

-Process of causing microorganisms to act on treated material-
The microorganism (C13a) was inoculated into 100 mL of YES-G medium and cultured with shaking to obtain a preculture solution. The culture conditions were 40 ° C., 140 rpm, and 11 days.
10 mL of the preculture solution thus obtained was added to 1 L of YES-G medium and shake-cultured to obtain a main culture solution. The culture conditions were 40 ° C., 140 rpm, and 9 days.
50 mL of the main culture solution was added to the 100 mL Erlenmeyer flask containing the material to be processed prepared above and shake-cultured. The culture conditions were 40 ° C. and 80 rpm.
The period during which microorganisms are allowed to act was one week.

-Evaluation-
After each culture period, the bacterial solution was discarded, and the material to be treated was rinsed with distilled water and then ultrasonically washed with 99% ethanol. Further, the material to be treated was washed with distilled water and then dried at 40 ° C. overnight.
(Microscopic observation)
The cell state of the obtained material to be treated (urethane foam) was observed with a microscope. The result is shown in FIG. The photograph shown in the upper right in FIG. 1 shows the state of the cell of the foamed resin according to the present invention, and the photograph shown in the lower right is an enlarged view thereof. Moreover, the photograph shown on the upper left in FIG. 1 shows the state of the material to be processed (foamed urethane) before decomposition (before the action of microorganisms) as a reference example, and the photograph shown on the lower left is an enlarged view thereof.
As shown in FIG. 1, a fine cavity of about several microns (1 μm to 3 μm) was observed on the wall surface of the independent bubbles. In addition, it was observed that this fine cavity penetrated into the cell.
(Electron microscope observation)
Furthermore, the to-be-processed material obtained as mentioned above was observed with the electron microscope. The result is shown in FIG. In FIG. 2, the photograph shown at the upper left is a photograph showing the observation result of a certain portion of the foamed resin according to the present invention, and the photograph shown at the upper right is an enlarged photograph of a portion indicated by A in the upper left photograph. 2 is a photograph showing an observation result of another portion of the foamed resin according to the present invention, and a photograph shown in the lower right is an enlarged photograph of a portion indicated by E in the lower left photograph. .
As shown in FIG. 2, it was confirmed that the hyphae were stretched in the fine cavity and the hyphae penetrated into the back of the small holes.

[Example 2]
-Grinding treatment-
The material to be treated (foamed urethane) obtained in Example 1 was pulverized using an ultracentrifugal pulverizer (Retsch (registered trademark) ZM200, Vider Scientific Co., Ltd.).
As a result, unlike conventional urethane foam having independent bubbles, it could be easily pulverized even at room temperature, and a finely pulverized product having an average particle size of 300 μm or less could be obtained. A photograph of the pulverized product is shown in FIG.

[Example 3]
A foamed resin of the present invention was obtained in the same manner as in Example 1 except that the action period of the microorganisms on the material to be treated was changed to 2 weeks, 4 weeks, and 9 weeks.

-Evaluation-
(Microscopic observation)
The photograph which observed the state of the foaming cell with the microscope similarly to Example 1 is represented in FIG. In FIG. 4, “1W”, “2W”, “4W”, and “9W” mean that the return with the action of microorganisms is a foamed resin of 1, 2, 4, and 9 weeks, respectively. .
As shown in FIG. 4, it can be seen that when a microorganism is allowed to act for one week, a fine cavity is formed and gradually progresses. Thereby, it comes to have the material characteristic which has both flexibility and resilience.

(Water absorption rate)
The water absorption rate of the foamed resin obtained in Example 1 and each of the foamed resins obtained in Example 3 was measured. The water absorption was measured as follows.
Moreover, after measuring foamed resin using the electronic balance, the foamed resin was added to the beaker containing water, and it stirred for 3 minutes using the stirring bar. The speed of the stirrer was such that water could not spill and could be stirred vigorously. Thereafter, a filter paper was set on the funnel, the foamed resin was drained, the moisture on the surface of the foamed resin was wiped off, and the weight was weighed with an electronic balance.
A graph of the results is shown in FIG.
In FIG. 5, “before decomposition” means urethane foam which has not been pretreated with fatty acids or treated with microorganisms. The “pretreated product” means urethane foam that has only been treated with oleic acid diluted with ethanol. “Decomposed 1W”, “Decomposed 2W”, “Decomposed 4W”, and “Decomposed 9W” mean that the foamed resin has a period of 1 week, 2 weeks, 4 weeks, and 9 weeks in which the microorganisms acted.
As shown in FIG. 5, it can be seen that the foamed resin of the present invention has greatly improved water absorption by 4 times or more. As described above, the foamed resin of the present invention is a material having the characteristics of simultaneous foaming while maintaining the high elasticity of independent foaming.

(Water retention)
About the foamed resin which absorbed the water as mentioned above, it was measured how the amount of water retention changed with time. The result is shown in FIG.
In FIG. 6, “undecomposed” is foamed urethane having independent bubbles before the action of microorganisms, “degraded product” is the foamed resin of the present invention in which microorganisms were allowed to act for one week, and “sponge” is used for comparison. This means a sponge having continuous air holes.
As shown in FIG. 6, it was found that the foamed resin of the present invention has a small water retention change and high water retention compared to foamed urethane having independent bubbles and a sponge having continuous air holes. This is because the foamed resin of the present invention is easily absorbed by the capillary phenomenon due to the formation of fine cavities, and the water inside the fine cavities is less likely to be dissipated by the surface tension of water. It is done.

(Sound absorption characteristics)
The sound absorption characteristics of the foamed resin of the present invention obtained in Example 1 and the pulverized product of the present invention obtained in Example 2 were evaluated. The sound absorption characteristics were evaluated according to ISO 10534-2 and ASTM E 1050 using a normal incidence sound absorption measurement system (DS2000) manufactured by Ono Sokki Co., Ltd.
Specifically, a system that calculates normal incidence sound absorption coefficient, reflection coefficient, and standardized impedance by radiating sound waves from the speaker built into the acoustic impedance tube end into the tube and measuring the transfer function between two microphones in the tube It is. The specifications of the acoustic impedance tube were changed in the high frequency range and low frequency range. The B tube in the high frequency region has a length of 500 mm and an inner diameter of 29φ, and the A tube in the low frequency region has a length of 835 mm and an inner diameter of 100φ.
The results are shown in FIGS.

  In FIG. 7, “initial pulverization” means one obtained by pulverizing urethane foam having independent bubbles, which has not been pretreated with fatty acids or treated with microorganisms, to a size of about 5 mm square. Similarly, “pre-treatment” means that the initial pulverized product is only treated with oleic acid diluted to 10% (W / W) with 99% ethanol, and does not act on microorganisms. In a state containing oleic acid. “After decomposition (residual fatty acid)” means that a microorganism is allowed to act for 1 week after pretreatment with oleic acid, and the sample contains oleic acid. “Degraded product (defatty acid)” means oleic acid contained in a sample after ultrasonically washing the sample with 99% alcohol after allowing microorganisms to act for 1 week after pretreatment with oleic acid Means that is completely removed. "Secondary grinding (residual fatty acid)" is a secondary grinding of microorganisms that have been pretreated with oleic acid for 1 week (about 5mm square, this is called "primary ground product") In this way, the sample is finely processed, and the sample contains oleic acid.

  In FIG. 8, “secondary pulverization (residual fatty acid)” means the same as “secondary pulverization (residual fatty acid)” in FIG. 7, and “cinsalate” means a sound absorbing heat insulating material manufactured by 3M. “Nagoya Packing” means a sound absorbing material manufactured by Nagoya Packing Manufacturing Co., Ltd., and “Refrigerator” means a sound absorbing heat insulating material used in a refrigerator manufactured by Mitsubishi Electric Corporation.

  As shown in FIG. 7, when a fine cavity was formed in the initial pulverized product, a slight improvement in sound absorption characteristics was observed, but the sample with the fine cavity formed was processed and pulverized. It was found that the sound absorption rate was significantly improved when measured with a sample. In particular, a large effect is observed in the high frequency region of 2000 Hz or more, and the characteristics are similar to a synthesizer with a track record as a sound absorbing material.

  In order to draw out the sound absorption effect, a highly efficient material that absorbs vibration energy of sound and converts it into heat energy is suitable as a sound absorbing member. It is considered that the pulverized product itself is an elastic body and easily absorbs energy, and that the pulverized product itself vibrates macroscopically, and the sound absorption rate is improved by the synergistic effect of these two phenomena. Compared to cinsalate, it can be expected to be used as a new sound-absorbing material that is very inexpensive.

Claims (4)

A method for producing a foamed resin having a structure in which at least some of the independent bubbles are linked by the action of microorganisms ,
Treating the foamed resin with an unsaturated fatty acid;
A step of causing microorganisms to act on the foamed resin treated with the unsaturated fatty acid;
Including
The foamed resin is foamed urethane,
The microorganism is a microorganism belonging to the genus Streptomyces having urethane decomposability,
Manufacturing method of foamed resin . Having a step of pulverizing the foamed resin obtained by the method for producing a foamed resin according to claim 1;
A method for producing a pulverized product . A method for producing a water-absorbing material comprising a pulverized foamed resin having a structure in which at least some of the independent bubbles are linked by the action of microorganisms,
Treating the foamed resin with an unsaturated fatty acid;
A step of causing microorganisms to act on the foamed resin treated with the unsaturated fatty acid;
Crushing the foamed resin after allowing the microorganisms to act;
Including
The foamed resin is foamed urethane,
The microorganism is a microorganism belonging to the genus Streptomyces having urethane decomposability,
Manufacturing method of water absorbing material . A method for producing a sound-absorbing material comprising a pulverized foamed resin having a structure in which at least some of the independent bubbles are linked by the action of microorganisms,
Treating the foamed resin with an unsaturated fatty acid;
A step of causing microorganisms to act on the foamed resin treated with the unsaturated fatty acid;
Crushing the foamed resin after allowing the microorganisms to act;
Including
The foamed resin is foamed urethane,
The microorganism is a microorganism belonging to the genus Streptomyces having urethane decomposability,
A method for producing a sound absorbing material .