JP2001219061A - Porous absorbing material and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain porous particles enhanced in moisture absorbing/releasing property by granulating fine powder, which has 1 mm or smaller particle size and is produced when a porous mineral is pulverized and is originally to be dumped, and reusing it and to provide a method for manufacturing the porous particles. SOLUTION: An excess of porous mineral fine particles is mixed in an aqueous solution containing a water-soluble macromolecule as a principal component, which is then kneaded. The kneaded material is granulated into large aggregated (granulated) particles, which are then dried to form granular coarse particles so that the objective porous particles more enhanced in performance to absorb moisture content or gas are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for producing water and ammonia gas by agglomerating a powder mainly composed of mineral particles having a fine pore size of 1 mm or less and having fine pores into coarse porous particles. The present invention relates to a porous absorbent having a function of absorbing and releasing a gas such as formaldehyde gas and suitable as an environmental control material, and a method for producing the same.

[0002]

2. Description of the Related Art In Japan, a large amount of mineral resources having fine pores such as zeolite and diatomaceous earth are buried, light with fine pores, and a property of adsorbing various substances. It is used for various purposes including light weight aggregates, fertilizers, agricultural chemical extenders, soil conditioners, and the like. Among them, zeolite has a large amount of reserves in Japan and has remarkable properties such as moisture absorption and desorption properties, so focusing on these properties, in recent years, zeolite has been crushed and coarse-grained It is being used as an underfloor drying material that can be laid and absorb moisture rising from the ground.

However, when pulverizing porous ore such as zeolite, a large amount of fine powder having a particle size of 1 mm or less is generated, and most of the fine powder is eventually discarded without being used. It is the current situation.

However, although zeolite is porous, its porosity is not so large and its specific gravity is relatively high. Therefore, there is a problem that the zeolite is heavy when applied as a drying material under the floor of a house and is not easy to handle. Also, the hygroscopicity is not as strong as expected. In addition, the problem that the change in the amount of moisture absorbed and released by the zeolite due to the change in humidity was slow was also recognized.

Further, when used as such a hygroscopic agent, if the particle size is 1 mm or less, the deposited zeolite layer becomes dense, and the flow of air and gas into the layer is significantly reduced. There is also a problem that the moisture release performance is further reduced. This is a problem common not only to zeolite but also to mineral powder having pores such as diatomaceous earth and sepiolite.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to recycle a fine powder having a particle size of 1 mm or less, which should be discarded, which is generated when pulverizing a porous mineral, into granules. Another object of the present invention is to provide a porous particle having improved and improved moisture absorption and release properties and a method for producing the same.

[0007]

In order to solve the above-mentioned problems, an aqueous solution containing a water-soluble polymer as a main component for the purpose of aggregating (granulating) porous mineral fine particles generated during pulverization. It is possible to further improve moisture and gas absorption performance by compounding and kneading excess porous mineral fine particles, kneading them, granulating them into large aggregated particles, and drying them to form granular coarse particles. it can.

[0008] The water-soluble polymer used in this case is polyethylene glycol, polyvinyl alcohol and its derivatives, polyvinylpyrrolidone, sodium or ammonium salts such as polyacrylic acid or polymethacrylic acid or urea adduct thereof, polyacrylamide,
Cellulose derivatives such as carboxymethylcellulose and methylcellulose, chitosan and its derivatives, alginic acid and its salts, agar, vegetable gums such as arabic gum, starch and its derivatives, and water-soluble polymer compounds such as proteins such as glue and milk casein And a selected one or a mixture of two or more of them can be used.

When these water-soluble polymers are made into an aqueous solution, they vary depending on the type and the degree of polymerization.
Use the one adjusted to the concentration of%. Furthermore, a thermoplastic resin emulsion such as a polyvinyl acetate resin or a polyacrylate resin, or a synthetic rubber latex such as styrene-butadiene rubber, acrylonitrile-butadiene rubber, or a natural rubber latex is mixed with the aqueous solution in an arbitrary ratio. Is also good.

As the porous mineral particles used in the present invention, inexpensive minerals such as diatomaceous earth, zeolite, perlite and sepiolite are used, but zeolite is preferably used in view of the availability and the abundance of resources. It is.

[0011] Furthermore, by mixing and using activated carbon, sawdust and charcoal of wood waste chips, or charcoal of agricultural waste such as straw and corn stalk, bark powder of cedar, hinoki and larch, etc. Moisture release performance, adsorption performance for formaldehyde, ammonia gas, and the like can be further improved and improved. At that time, the amount of these additives is 1 to 50% based on the mineral powder,
Preferably, it is 5 to 30%.

The effect of the present invention can be obtained by dissolving a compound which easily reacts with formaldehyde, such as an amino compound such as urea, an amine compound or an amino compound, as a powder or in an aqueous solution of a water-soluble polymer. Can be further improved.

[0013] The method for producing the porous absorbent material of the present invention comprises:
For example, when polyvinyl alcohol is used as the water-soluble polymer, the aperture is 1 mm for 1 part by weight of the aqueous solution.
The particles of the porous mineral having a particle size that has passed through the sieve are added with stirring at a ratio of 0.5 to 100 parts by weight, preferably 1 to 20 parts by weight, and secondary aggregated. At that time, a device such as a usual stirrer or kneader is used. The kneaded and granulated product is dried in a drier kept at a temperature of 50 to 200 ° C. At that time, a water-proofing agent that reacts with a water-soluble polymer such as an epoxy compound or an isocyanate compound to crosslink. May be added to the aqueous solution of the water-soluble polymer in an amount of 1 to 20%.

The concentration of the aqueous solution of the water-soluble polymer is generally adjusted to a lower concentration as the degree of polymerization of the water-soluble polymer becomes higher.
In addition, as the viscosity of the aqueous solution is lower, the ratio of the porous mineral particles to be added can be increased.

Next, regarding the porous absorbent according to the present invention,
The following describes test examples.

Test Example 1 200 g of zeolite powder having a particle size of 1 mm or less was added to 50 g of a 10% aqueous solution of polyvinyl alcohol (PA-05GA manufactured by Shin-Etsu Chemical Co., Ltd.) with vigorous stirring to form an aggregate, and the mixture was heated to 110 ° C. It was left to dry in the held dryer for 3 hours. The sample thus adjusted and zeolite pulverized to a particle size of 3 to 6 mm were each taken in a Petri dish having a diameter of 90 mm, dried again until absolutely dry, and then weighed. The weight at that time was defined as 100. 3 in a constant temperature and humidity room at 30 ° C and 90% RH
After allowing to stand for a time, the weight change rate was measured. After leaving it under the same conditions for further 10 hours, it was transferred to a thermo-hygrostat at 30 ° C. and 30% RH, and the weight change rate after 3 hours was measured. The results are shown in Table 1. As is clear from these results, the aggregated zeolite exhibited superior moisture absorption / release properties as compared with the granular zeolite.

[0017]

[Table 1]

Test Examples 2 to 4 500 g of zeolite powder having a particle size of 1 mm or less, 50 g of cedar bark powder, activated carbon, and powdered urea were mixed with 50 g of a 10% aqueous solution of polyvinyl alcohol (Kuraray PVA-117). After adding with vigorous stirring and aggregating, 110 ° C
For 3 hours in a drier kept for 1 hour. The sample thus adjusted and the zeolite agglomerated in Test Example 1 were each taken in a Petri dish having a diameter of 90 mm, dried again until absolutely dry, and then weighed. The weight at that time was defined as 100. Next, a desiccator having an internal volume of about 10 l and a diameter of 12 c containing 300 ml of distilled water at the bottom.
A crystal dish having a height of 6 cm and a height of 6 cm was placed, and a 10-ml weighing bottle in which 0.5 ml of a solution prepared by diluting 0.2 ml of 37% formalin with 5 ml of distilled water was placed therein, and each was placed in a petri dish. Sample was placed. The measured value of formaldehyde gas in the desiccator containing only formalin and sealed for 48 hours was 11.9 mg / l. Furthermore, after the desiccator on which each sample was placed was sealed, the sample was allowed to stand in a constant temperature and humidity room maintained at a temperature of 20 ° C. and a relative humidity of 65% for 48 hours. After a predetermined time, the concentration of formaldehyde absorbed in the distilled water in the crystallizing dish placed in the desiccator was measured by the acetylacetone method specified in JIS-5908. The results are shown in Table 2. As is clear from the results, it is clear that cedar bark chips, activated carbon, and urea powder added to the aggregated zeolite and the aggregated form of zeolite absorb formaldehyde gas better.

[0019]

[Table 2]

From the results of the above test examples, the particle size was 1 mm
By adding an aqueous solution mainly composed of a water-soluble polymer to the following porous mineral powder with stirring and aggregating, and drying to form an aggregated mineral powder, it is possible to significantly improve the moisture absorption / release performance. In addition, by adding bark powder or chips, activated carbon, carbide powder, amino compound powder and the like during agglomeration, it is possible to further improve and improve the moisture absorption / release properties and the absorption performance of formaldehyde gas and the like.

[0021]

The effect of the present invention is due to the fact that the pores of the porous mineral powder particles are further increased, and is caused by increasing the adsorption area of water and gas. The addition of bark powder, chips, amino compounds and the like to the mineral particles has the effect of reacting with formaldehyde gas and the like adsorbed to immobilize the mineral particles.

The aggregated mineral particles having such an effect can be laid under the floor of a house and used as a moisture proof material under the floor for preventing moisture radiated from the ground.

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Claims (6)

[Claims] 1. A porous absorbent formed by using an aqueous solution containing a water-soluble polymer as a main component, and forming a powder mainly containing mineral particles having fine pores having a particle diameter of 1 mm or less into a granular form. . 2. The porous absorbent according to claim 1, wherein the mineral particles having fine pores are zeolite. 3. A powder mainly composed of mineral particles having fine pores is selected from the group consisting of zeolite and activated carbon, charcoal powder of woody or agricultural waste, bark powder, urea, amine compound,
The porous absorbent according to claim 1, wherein a compound having an amino group such as an amino acid is mixed. 4. An aqueous solution containing a water-soluble polymer as a main component is mixed with a powder mainly containing mineral particles having fine pores having a particle size of 1 mm or less and stirred or kneaded to form an aggregate.
A method for producing a porous absorbent material, comprising drying. 5. The method for producing a porous absorbent according to claim 4, wherein the mineral particles having fine pores are zeolite. 6. A powder mainly composed of mineral particles having fine pores having a particle diameter of 1 mm or less is selected from the group consisting of zeolite and activated carbon, charcoal powder of woody or agricultural waste, bark powder, and amino such as urea, amine compound and amino acid. The method for producing a porous absorbent according to claim 4, wherein a compound having a group is mixed.