JPH11123328A - Adsorbing/desorbing material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the production and handling of a product which has a low bulk density, is good in adhesion, water resistance, and thermal stability, and exhibits no deterioration in adsortion/desorption performance in comparison with a powdered adsorbent by dispersing an adsorbent in a poly(ether sulfone) resin. SOLUTION: An adsorbent is preferably in the form of a fine powder in view of dispersability. An adsorbing/desorbing material can be obtained from a solution in which the adsorbent is dispersed uniformly in a poly(ether sulfone) resin solution by a so-called sol-gel method. In a practical operation, for example, after the solution in which the adsorbent is dispersed in the poly(ether sulfone) resin solution being applied on a substrate, it is immersed in a solvent (nonsolvent) which poorly dissolves the poly(ether sulfone) resin and has affinity with a solvent used for dissolving the resin used for dissolving the resin to obtain a coating film in which adsorbent particles are not flocculated in a poly(ether sulfone) resin porous material but are dispersed uniformly as fine particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel adsorption / desorption material and a method for producing the same. The absorption / desorption material of the present invention has accelerated adsorption / desorption performance, and can be used as an adsorption material, a deodorant material, a humidity control material, a separation material, a catalyst material and the like.

[0002]

2. Description of the Related Art Powdered adsorbents having a high bulk density, such as activated carbon, are difficult to handle, so that these adsorbents are solidified using a binder. However, when a binder is used, the pores of the adsorbent are blocked or closed, so that the apparent surface area of the adsorbent is reduced and the adsorbability is significantly impaired.

Japanese Patent Application Laid-Open No. 7-41596 discloses a method for producing activated carbon particles in which activated carbon is coated with porous polymer particles using a porous polymer gel obtained by a suspension polymerization method without impairing the adsorption performance. It has been disclosed. However, the surface area of the activated carbon prepared by this method by the BET method is about one-third.
To decline. In addition, since activated carbon must be included at the same time as the polymerization reaction, a sufficient amount of activated carbon cannot be added, the yield is not good, and powder falls off from the obtained particulate activated carbon.

Japanese Patent Application Laid-Open No. 02-17989 discloses a method of molding by mixing a thermoplastic resin powder having a particle size larger than the particle size of activated carbon. However, in this method, it is necessary to mold the resin powder without impairing the porosity, so setting the molding conditions is difficult, and the strength of the molded article molded by this method is not sufficient. .

[0005] Japanese Patent Application Laid-Open No. 63-109046 proposes a dew condensation preventing sheet in which activated carbon and porous urethane are combined. However, in order for the sheet produced by this method to exhibit sufficient performance, it is necessary to use activated carbon having a large particle size.
Therefore, it is necessary to overcoat the porous urethane layer in multiple layers in order to prevent the detachment of the activated carbon. Furthermore, due to the properties of the urethane resin, the water resistance and heat resistance are poor.

Japanese Patent Application Laid-Open No. 53-28094 discloses a method of removing impurities in a polyacrylonitrile copolymer solution containing activated carbon as an adsorbent by a sol-gel transition method. There are examples.
However, in the membrane obtained by this combination, the pores of the adsorbent are significantly blocked by a resin such as polyacrylonitrile, so that the gas adsorption speed and the amount of adsorption decrease. In addition, since it has poor solvent resistance and heat resistance, it cannot be used repeatedly due to a temperature swing or the like.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide adhesiveness, water resistance, solvent resistance, and thermal stability, and to decrease the absorption / desorption performance as compared with a known powdery adsorbent. An object of the present invention is to provide an absorbent / desorbable material which has low bulk density and is easy to manufacture and handle.

The present inventors have studied a wide range of properties of a composite material of a heat-resistant and chemical-resistant polymer compound capable of forming a porous film with an adsorbent, and have found that a polyether-based polymer is adsorbed with a polyether-based polymer. That the composite with the agent gives a coating film with excellent substrate adhesion and porosity, and surprisingly, its absorption and desorption performance is superior to that of the corresponding raw material adsorbent Thus, the present invention has been completed.

[0009]

The absorbing / desorbing material provided by the present invention is characterized in that an adsorbent is dispersed in a polyethersulfone resin. The present invention provides a method for producing the above-mentioned absorbent / desorbable material. The method of the present invention is characterized in that an adsorbent is dispersed in a solvent obtained by dissolving a polyethersulfone resin in a solvent, and the obtained solution is brought into contact with a non-solvent of the polyethersulfone resin. Still another object of the present invention is to use a composite material in which an adsorbent is dispersed in a polyethersulfone-based resin as a material for absorbing and desorbing.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The polyethersulfone resin used in the present invention means a resin having a heat-resistant aromatic sulfone group and an aromatic ether group in a molecule. This polyether sulfone resin generally has excellent heat resistance,
Shows mechanical strength and chemical resistance. Preferred polyethersulfone resins are selected from those having a reduced viscosity of 0.1 or more and 1 or less measured with 1% dimethylformamide.

Although the form of the adsorbent is not particularly problematic, it is preferably in the form of a fine powder from the viewpoint of dispersibility,
It is desirable that it is not more than μm. Although the type of the adsorbent is not particularly limited, activated carbon, graphite, charcoal, zeolite, aluminosilicate, fryponite, magnesium oxide, metal phthalocyanine, sepiolite, bentonite, porous silica, kaolinite, calcium silicate, montmorillonite, halosite, Examples include hydroxyapatite, allophane, diatomaceous earth, other clay minerals, metal oxides, and the like. In addition, these adsorbents can be used to modify and modify the surface, add other performances, and improve them.

The amount of the adsorbent dispersed in the polyethersulfone resin is preferably from 10 to 200 parts by weight based on 100 parts by weight of the polyethersulfone resin. If the amount is less than 10 parts by weight, not only the adsorption performance is insufficient, but also the adhesion and smoothness of the obtained coating film become poor. The mechanical strength of the containing polymer porous body decreases.

The adsorption / desorption material of the present invention can be obtained by a so-called sol-gel method from a solution in which the above adsorbent is uniformly dispersed in a polyethersulfone resin solution. The solvent for dissolving the polyethersulfone resin is not particularly limited, but typical solvents include N-methylpyrrolidone, formamide, dimethylformamide, dimethylacetamide, dimethylsulfoxide, γ-butyrolactone, tetramethylurea, and trimethylphosphate. And the like. Mixed solvents can also be used. Usually, the polyethersulfone resin is dissolved in these solvents in an amount of 5 to 40% by weight. On the other hand, examples of the non-solvent which is a solvent that does not dissolve the polyethersulfone-based resin include water and alcohols.

When a coating film is obtained, it is preferable to use water as the non-solvent from the viewpoint of the strength and adhesion of the coating film. Immediately after the polyethersulfone resin is immersed in the non-solvent, the sol-gel transition starts, but it is preferable to take an immersion time of 10 seconds or more in order to sufficiently promote gelation. After sufficient immersion time and drying, a water-repellent, adsorptive coating is obtained. When a yarn is obtained, it is preferable to use water as a non-solvent from the viewpoint of mechanical strength.

In an actual operation, for example, a solution in which an adsorbent is dispersed in a polyethersulfone-based resin solution is applied to a substrate, and then the polyethersulfone-based resin is poorly soluble in the polyethersulfone-based resin. By immersing in a solvent (non-solvent) that has an affinity for the solvent used to dissolve the adsorbent, the adsorbent particles are uniformly dispersed as fine particles without agglomeration in the porous polyethersulfone resin. Is obtained.

As the substrate, not only a porous substrate but also a non-porous substrate can be used. In any case, an adsorptive material having strong adhesion and high film strength can be obtained. Examples of the porous substrate include stainless steel, paper, wood, glass or plastic woven / nonwoven fabric, porous glass / ceramics, and the like. Further, examples of the non-porous substrate include various metal foils and sheets, plastic films and sheets, and ceramics.

[0017] The coating amount is 10 μm to 1,000 μm
Is preferably such that If the coating amount is less than 10 μm, the porosity of the obtained porous membrane becomes small, and the adsorption performance is reduced. Conversely, if the thickness exceeds 1,000 μm,
The non-solvent cannot be sufficiently exchanged, and it becomes difficult to obtain a good porous membrane. Instead of applying the polyethersulfone-based resin solution on the base material, the solution may be spun or the droplets may be dipped in a non-solvent to obtain a thread-like absorbing / desorbing material.

In the material thus obtained, the adsorbent is hardly covered with the polyethersulfone-based resin, and the primary particles of the adsorbent are independently and directly contained in the pores formed in the polymer matrix. It has a unique structure that exists. Therefore, a material having an excellent adsorption rate can be obtained as compared with the case where the organic polymer matrix is acetyl cellulose, acrylonitrile, polyamide, polyimide, polyester, or the like. In addition, the adsorbent does not desorb with the solvent at the time of gelation, and almost all of the adsorbent is taken into the porous polymer matrix. I can't. In addition, the coating film formed on the substrate may be peeled from the substrate to obtain a film.

To the adsorptive material of the present invention, other polymer compounds and additives can be added as long as the performance is not impaired. Other polymer compounds can be used to form a porous body by the sol-gel transition method, and can also be used as compounds for controlling the morphology of the porous body. As the additives, various surfactants, dispersants, pigments, dyes, fillers, water-soluble compounds, bactericides, and other functional compounds can be used. For the purpose of further improving the mechanical strength of the film, glass, plastic, fiber, metal, whisker of metal oxide or the like can be mixed and used. The adsorptive material of the present invention can be used as an adsorbent material, a deodorant material, a humidity control material, a separation material, and a catalyst material because of its excellent absorption / desorption performance. Hereinafter, examples of the present invention will be described, but the present invention is not limited to the following examples.

[0020]

EXAMPLE 1 15 parts by weight of Sumika Excel PES-4800P (a polyether sulfone resin manufactured by Sumitomo Chemical Co., Ltd.) was mixed with 85 parts by weight of N
-Methylpyrrolidone and 15 parts by weight of N
K-10 (a zeolite powder manufactured by SECA) was dispersed.
The obtained dispersion is cast on a glass plate, and then immersed in water to thereby absorb and desorb the material of the present invention having a thickness of 200 μm (referred to as porous film A including the base film).
I got No detached zeolite powder was observed in the water. The density of the obtained adsorption / desorption material portion of the present invention after drying was 0.70 g / cm ³ . The dried porous membrane A
Was allowed to stand at room temperature in an atmosphere having a humidity of 90% for 5 minutes, and the weight increase was measured. 15% weight gain based on zeolite weight
Met. That is, water of 15% of the weight of the zeolite was adsorbed in 5 minutes.

Comparative Example 1 The same amount of NK-1 as in Example 1 under the same humidity conditions as in Example 1.
Using 0 powder, the weight increase after 30 minutes was measured. The weight gain was 5% based on the weight of the zeolite. On the other hand, the weight increase of a commercial product obtained by molding the same zeolite powder into beads using an inorganic binder was 1% after 30 minutes. As described above, the porous membrane of the present invention was superior not only to the bead-shaped molded product but also to the zeolite powder itself in the rate of adsorbing moisture.

Comparative Example 2 As a porous polymer precursor, an acrylonitrile-methacrylic acid copolymer (9
0:10), except that sol.
Gel transition was performed. Immediately after immersion in water, peeling of the film was observed. The water absorption capacity of the peeled coating film is 1% after 10 minutes
Met.

Comparative Example 3 200 parts by weight of polyethylene adipate diol (molecular weight = 2,000) instead of the polyether sulfone resin of Example 1
And a 15% solids polyurethane DMF solution synthesized from 98 parts by weight of 4,4'-diphenylmethane diisocyanate and 16 parts by weight of ethylene glycol. The water vapor absorption capacity of the porous membrane obtained by immersion in water after coating was 1% after 10 minutes. Thus, the porous membrane of the present invention
It has a higher moisture adsorption rate than a porous film using a non-heat-resistant acrylonitrile-methacrylic acid copolymer or polyurethane.

Example 2 10 parts by weight of ENO (fine powder of activated carbon manufactured by Elf Atochem Co.) was dispersed in the polymer solution of Example 1, and immersed in water in the same manner as in Example 1 to make the activated carbon uniform. Dispersed thickness 200
The absorption / desorption material of the present invention having a thickness of μm was obtained (referred to as porous membrane B including the base film). The density of the obtained adsorption / desorption material portion of the present invention after drying was 0.50 g / cm ³ . The porous membrane B was allowed to stand still at room temperature in an atmosphere having a relative humidity of 90%, and the water absorption capacity was measured. After 30 minutes, 16% by weight of activated carbon
, And after 18 hours, 37% of the weight of activated carbon was absorbed. After 18 hours, the sample was allowed to stand for 1 hour in an atmosphere at room temperature and a relative humidity of 50%, and released 24% of water in terms of the weight ratio of activated carbon. The weight increase due to water absorption was reduced to 13%. I was

Comparative Example 4 As a porous polymer precursor, an acrylonitrile-methacrylic acid copolymer (9
0:10), except that sol
Gel transition was performed. The water absorption capacity of the peeled coating film is 50
After an hour, the weight ratio to activated carbon was 20%.

Example 3 The activated carbon-dispersed polymer solution of Example 2 was applied on a glass plate, immersed in water, and separated from the substrate to obtain a 100 μm absorbing / desorbing material of the present invention (porous membrane C). Was. No activated carbon residue left in the water was observed. After drying the porous film C at room temperature, it was allowed to stand at room temperature in a saturated benzene vapor atmosphere for 10 minutes. 46% of benzene was absorbed by activated carbon weight. After that, when it was usually left in a room, 90% of the absorbed benzene had been desorbed after 10 minutes. The porous film C dried at room temperature was allowed to stand at 180 ° C. for 100 hours, and then allowed to stand at room temperature in a saturated benzene vapor atmosphere for 10 minutes. Similarly, 46% of benzene was absorbed by the weight of activated carbon contained. After that, when it was usually left in a room, 90% of the absorbed benzene had been desorbed after 10 minutes. Thus, the porous membrane of the present invention has excellent thermal stability. Further, the porous membrane C dried at room temperature was added to various chemicals shown in [Table 1] at each temperature.
It was immersed for 24 hours and its appearance was visually observed. The results are shown in [Table 1]. Thus, the porous film of the present invention was excellent also in solvent resistance.

[0027]

[Table 1]

Comparative Example 5 The fine powdered activated carbon used in Example 4 was absorbed in the same benzene vapor as in Example 4 for 10 minutes. 35% by activated carbon weight
Had absorbed benzene. After that, 10
The desorption amount after one minute was 20%. After that, when it was usually left in a room, 10 minutes later, 20% of the absorbed benzene had been desorbed. Thus, the porous membrane of the present invention is superior in the benzene adsorption and desorption rates to the activated carbon powder itself.

Example 4 15 parts by weight of Sumika Excel PES-5200P (a polyether sulfone resin manufactured by Sumitomo Chemical Co., Ltd.) was dissolved in 85 parts by weight of dimethylacetamide. 15 parts by weight of Lionion SF (a silicate mineral-based adsorbent manufactured by Lion Corporation) is dispersed in this solution, cast on glass fibers, and then immersed in water to obtain a thickness that is adhered to the glass fibers. Of the present invention (hereinafter referred to as porous film D including the substrate) having a particle size of 500 μm. No separated silicate mineral was observed in the water. A 50 cm ² sample of this coating was placed in a 1.8 liter container containing 250 ppm of ammonia and a detector tube (Kitakawa
(SD type). After 1.5 hours, the ammonia concentration had dropped below 10 ppm. This experiment showed that the adsorption / desorption material of the present invention adsorbs ammonia.

Comparative Example 6 The same amount of Lionion SF used in Example 4 was placed in a 1.8-liter container, and the rate of ammonia reduction was measured in the same manner as in Example 4. It took 4 hours to reach below 10 ppm.

[0031]

As described above, the adsorbing / desorbing material of the present invention comprises:
It has low bulk density, excellent adhesion, water resistance, solvent resistance, and thermal stability, does not decrease in absorption / desorption performance as compared with powdered adsorbents, and is easy to manufacture and handle.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Kuniyuki Goto 3-23 Kioicho, Chiyoda-ku, Tokyo Elf Atochem Japan K.K. Asahi Denka Kogyo Co., Ltd.

Claims (5)

[Claims] 1. A porous adsorbent / desorbable material comprising an adsorbent dispersed in a polyethersulfone resin. 2. The method according to claim 1, wherein the adsorbent is activated carbon, graphite, charcoal,
2. The absorbent / desorbable material according to claim 1, which is one or more selected from the group consisting of zeolite, aluminosilicate, porous silica, metal oxide, and viscous mineral. 3. The absorbent / desorbable material according to claim 1, wherein the absorbent / desorbable material is a gas absorbent / desorbable material. 4. A polyethersulfone-based resin, comprising: dispersing an adsorbent in a solvent in which a polyethersulfone-based resin is dissolved; and contacting the resulting solution with a non-solvent of the polyethersulfone-based resin. A method for producing a porous absorbent / desorbable material in which an adsorbent is dispersed in a resin. 5. Use of a composite material in which an adsorbent is dispersed in a polyethersulfone-based resin as a porous absorbent / desorbable material.