JP2006265468A - Manufacturing method of formed body and formed body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a porous formed body which carries a functional substance, has large internal surface area, contains the functional substance and a target substance inside which can efficiently contact with each other without being affected by pressure loss and have sufficient strength, and to provide a formed body obtained by this method. <P>SOLUTION: The manufacturing method of the porous formed body carrying the functional substance comprises the steps of (1) preparing a dope by adding 100 pts.wt. of a polymer and 10-9,700 pts.wt. of the functional substance to 300-2,400 pts.wt. of a good solvent and (2) solidifying the dope in a solidifying solution, wherein ≥50 pts.wt. of the polymer is an aromatic polyamide. The formed body is obtained according to the manufacturing method. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a porous molded body carrying a functional substance. More specifically, the present invention relates to a method for producing a molded article in which a functional substance is supported without impairing the original performance such as adsorption activity and catalytic activity. The present invention also relates to a porous molded body obtained by the method.

In recent years, functional substances that decompose and adsorb substances that cause environmental problems have been actively developed. In order to facilitate the handling of the functional substance, various proposals have been made on molded articles carrying the functional substance.
For example, a method has been proposed in which a functional substance is mixed in a molten polymer and then extruded to obtain a fibrous or film-like molded body. Although this method has a large amount of functional material that can be carried on the molded body, there is a drawback that the molded body itself becomes dense and the contact between the functional material contained in the molded body and the target substance is hindered.

Also proposed is a composition in which adsorbent powder is dispersed in polyacrylonitrile, the dope is coagulated in a coagulating liquid through a base, and the adsorbent is dispersed in a polyacrylonitrile porous body. (See Patent Document 1). Since such a composition has a porous structure, the contact between the functional substance and the target substance is improved. However, polyacrylonitrile is difficult to solidify, and there is a limit to increasing the proportion of voids in the porous body, and there is room for further improving the contact between the functional substance and the target substance. In addition, polyacrylonitrile has a drawback that the alkali resistance is not sufficient and the polyacrylonitrile is dissolved when the catalyst is regenerated using an alkaline solution.
Japanese Patent Laid-Open No. 50-80985

  The present invention provides a porous material carrying a functional material that has a large internal surface area and can be efficiently contacted with the functional material contained therein and the target material without being affected by pressure loss and has sufficient strength. An object of the present invention is to provide a method for producing a shaped product. Another object of the present invention is to provide a molded article obtained by the method.

  The inventor has intensively studied to increase the proportion of voids in a porous molded body on which a functional substance is supported. When a molded body is produced by a wet process using aromatic polyamide, the proportion of voids is determined. The present invention has been completed by finding that a porous molded body having a large thickness can be obtained.

That is, the present invention includes (1) a step of preparing a dope by adding 100 parts by weight of a polymer and 10 to 9700 parts by weight of a functional substance to 300 to 2400 parts by weight of a good solvent, and (2) solidifying the dope. Solidifying in liquid,
A method for producing a molded body comprising a porous material carrying a functional substance, wherein 50% by weight or more of the polymer is an aromatic polyamide. Moreover, this invention includes the molded object obtained by the said method.

  According to the present invention, a molded article having macrovoids which are large voids inside and excellent in alkali resistance can be obtained. Since the molded article of the present invention has macrovoids separated by a polymer having pores, the functional substance supported in the molded article is not easily affected by pressure loss and can be efficiently contacted with the target substance. .

<Method for producing molded body>
The method of the present invention is a method for producing a molded body by a so-called wet method, which comprises coagulating a dope in a coagulating liquid.

(Dope preparation process)
The dope can be prepared by adding 100 parts by weight of a polymer and 10 to 9700 parts by weight of a functional substance to 300 to 2400 parts by weight of a good solvent.
At least 50% by weight of the total weight of the polymer added to the good solvent is aromatic polyamide. It is preferable that 80% by weight or more of the total weight of the polymer is an aromatic polyamide. More preferably, it is 90 weight% or more. In particular, the polymer is preferably composed only of an aromatic polyamide. Examples of the aromatic polyamide include polymetaphenylene terephthalamide and polyparaphenylene terephthalamide.
Examples of other polymers include polystyrene, amorphous polycarbonate, and polyvinyl alcohol.

  A good solvent is a solvent having a large solubility in a polymer. For example, when the polymer is polymetaphenylene terephthalamide, N-methyl-2-pyrrolidone, dimethylacetamide and the like. The proportion of the good solvent in the dope is 300 to 2400 parts by weight, preferably 500 to 1800 parts by weight, and more preferably 900 to 1800 parts by weight with respect to 100 parts by weight of the polymer.

The functional substance is preferably at least one selected from the group consisting of metal oxides, metals, inorganic substances, minerals, and synthetic resins. Examples of the metal oxide include titanium oxide, aluminum oxide, zirconium oxide, zinc oxide, and silica. Examples of the metal include gold, platinum, silver, iron, aluminum, stainless steel, copper, nickel, and manganese. Examples of the inorganic substance include activated carbon, hydrotalcite, gypsum, cement and the like. Examples of minerals include mica. Examples of the synthetic resin include polyethylene, polystyrene, polypropylene, polyester, and polyphenylene sulfide.
The functional substance is preferably particulate. The particle diameter of the particles is preferably 0.1 nm to 500 μm, more preferably 1 nm to 100 μm, and still more preferably 1 nm to 50 μm.

  In addition, a composite functional substance using silica, activated carbon or the like as a carrier and supporting a metal such as silver is also preferable. In this case, the particle diameter of silver is preferably 1 nm to 100 μm, more preferably 1 nm to 100 nm. Furthermore, it is also preferable to support two or more kinds of functional substances in the same molded body.

The ratio of the functional substance in the dope is 10 to 9700 parts by weight, preferably 100 to 1900 parts by weight, and more preferably 300 to 1900 parts by weight with respect to 100 parts by weight of the polymer.
The dope temperature is preferably 5 to 80 ° C, more preferably 20 to 50 ° C. The dope can be prepared by adding a polymer and a functional substance to a good solvent. The order of addition does not matter. That is, the polymer may be mixed in a good solvent and dissolved by sufficiently stirring, and then the functional substance may be added, or the polymer and the functional substance may be mixed simultaneously in the good solvent. Furthermore, a functional substance may be first mixed in a good solvent, and a polymer may be added later. When adding a polymer other than an aromatic polyamide, the aromatic polyamide and another polymer may be mixed and added to a good solvent, or the aromatic polyamide and the other polymer may be added separately to the good solvent. You may add to.

(Coagulation process)
The coagulation liquid is a poor solvent for the polymer. As generally said, a poor solvent is a solvent having a slight solubility in a polymer. Water is exemplified as the poor solvent. The temperature of the coagulation liquid is preferably 10 to 80 ° C, more preferably 20 to 50 ° C.
Aromatic polyamide is easy to coagulate in the coagulating liquid, and a molded product having macrovoids can be produced. It is also possible to adjust the macrovoid size by changing the concentration of the aromatic polyamide. In general, the higher the concentration of aromatic polyamide, the smaller the macrovoid size. In the present invention, the macro void means a void having a longest portion in a range of 1 to 150 μm.
On the other hand, according to the present invention, the so-called spinodal decomposition forms continuous pores in the polymer with a network structure having a longest pore diameter of 0.1 nm or more and less than 1 μm.

  No special apparatus is required to obtain the molded article of the present invention. The massive molded body can be solidified by adding the dope into the coagulation liquid. For example, it is only necessary to drop the dope into the coagulation liquid by spraying or using a syringe. Moreover, a fibrous molded object can be manufactured by discharging dope into a coagulation liquid with a nozzle and winding up. Moreover, a fibrous molded object can also be obtained by moving a micro syringe etc. horizontally, discharging dope with the micro syringe etc. from the air, and throwing dope into coagulation liquid. Moreover, a film-shaped molded object can be manufactured by apply | coating dope on a carrier substance and immersing in a coagulation liquid. In these cases, the diameter and thickness of the molded product can be arbitrarily adjusted by changing the diameter of the spray nozzle, the coating thickness, and the like.

<Molded body>
The present invention includes a molded article obtained by the above method. The shaped body is preferably formed from a polymer having pores and has macrovoids.
The molded body of the present invention is characterized in that the polymer itself constituting the molded body has pores, and macrovoids are formed by the polymer. The pores communicate with other pores in the polymer, forming a network structure in which the pores are connected. The longest part of the pore diameter is 0.1 nm or more and less than 1 μm, preferably in the range of 10 nm to 500 nm.

(shell)
The molded body of the present invention preferably has an outer shell. Since the outer shell is formed of a polymer, openings of a plurality of pores are observed on the surface of the outer shell, thus forming a porous structure. The pores communicate with other pores in the polymer to form a network structure in which the pores are connected. Such pores communicate with macro voids described later.
The thickness of the outer shell is preferably in the range of 100 nm to 1 μm, more preferably 200 nm to 500 nm. In the case of a spherical or ellipsoidal shaped body, it is preferably in the range of 0.005 to 0.05%, more preferably 0.01 to 0.025% of the diameter.

  In the case of a fibrous shaped body, it is preferably 0.005 to 0.05% of the diameter of the cross section perpendicular to the longitudinal direction of the shaped body, more preferably in the range of 0.01 to 0.025%. It is. Furthermore, in the case of a film-shaped molded body, the film thickness is preferably 0.005 to 0.1%, and more preferably 0.01 to 0.05%.

(Macro void)
The molded body of the present invention contains macrovoids separated by a polymer, and adjacent macrovoids are connected by pores in the polymer. The macrovoid has a maximum diameter of preferably 1 μm to 150 μm, more preferably 20 μm to 100 μm.

(Functional substances)
The functional substance is supported on the polymer of the molded body. Therefore, the functional substance is supported at any position of the outer shell and the macro void.
At least a part of the surface of the functional substance supported by the macrovoids inside the molded article of the present invention is covered with a polymer. The thickness of the coating is preferably in the range of 1 nm to 10 μm, more preferably 100 nm to 1 μm.

(Shape of molded product)
The molded body of the present invention is preferably in the form of a lump such as a sphere or an ellipse, a fiber such as a string, a pipe or a hollow fiber, or a film.

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

<Example 1>
100 parts by weight of N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP), 9.3 parts by weight of polymetaphenylene terephthalamide (Conex (registered trademark) manufactured by Teijin Techno Products Co., Ltd.), phosphorus The dope was prepared by adding 37 parts by weight of hydrotalcite (average particle size: 10 μm), which is an inorganic material that adsorbs.
Next, the dope was discharged into a coagulating liquid at a discharge amount of 2.18 g / min from a base of φ0.2 mm × 10 holes immersed in a coagulating liquid at 25 ° C. to obtain a fibrous shaped body. . The coagulation liquid consists of 100% by weight of water.
The molded body was washed with water and dried. The obtained molded body contains 80% by weight of hydrotalcite and 20% by weight of polymetaphenylene terephthalamide.

  In FIG. 1, the electron micrograph of the cross section of the obtained molded object is shown. According to the photograph, the macrovoid and the hydrotalcite supported on the macrovoid partition wall surface are observed. FIG. 2 is a local magnified electron micrograph (magnification 3000) of FIG. 1, showing that the hydrotalcite surface is coated with a polymer. It can also be seen that the coating polymer has fine communication holes.

<Example 2>
Using the fibrous molded body obtained in Example 1, a phosphate ion adsorption test was performed. That is, 0.625 g of the fibrous molded body obtained in Example 1 was added by dry weight to 1.5 liters of an aqueous Na ₂ HPO ₄ solution adjusted to a phosphorous concentration of 0.9 mg P / liter, and the temperature was lowered to 25 ° C. And stirred to such an extent that it does not settle. During stirring, the Na ₂ HPO ₄ aqueous solution was sampled periodically, and the phosphate ion concentration in the sample was quantified by the molybdenum blue method. The result is shown in FIG.

<Example 3>
NMP (100 parts by weight), polymetaphenylene terephthalamide (Teijin Techno Products Co., Ltd., Conex (registered trademark)) 8.9 parts by weight, polystyrene 2.2 parts by weight, and hydrotalcite (average particle size 10 μm) 138 parts by weight Part was added to prepare a dope.
Next, the dope was extruded into a coagulating liquid from a die having a diameter of 1 mm soaked in the coagulating liquid at 25 ° C. to be coagulated. The coagulation liquid consists of 100% by weight of water.
The strand-shaped molded body obtained by solidification was cut to obtain a cylindrical molded body having a length of 2 mm and a diameter of 0.8 mm. The dried molded body contains 92.5% by weight hydrotalcite, 6.0% by weight polymetaphenylene terephthalamide and 1.5% by weight polystyrene.

<Example 4>
Using the cylindrical shaped body obtained in Example 3, an adsorption test for phosphate ions was performed. That is, 0.54 g of the cylindrical shaped product obtained in Example 3 was added by dry weight to 1.5 liters of an aqueous Na ₂ HPO ₄ solution having a phosphorus concentration adjusted to 2.7 mgP / liter, and the temperature was raised to 25 ° C. The mixture was stirred to such an extent that it did not settle. During stirring, the Na ₂ HPO ₄ aqueous solution was sampled periodically, and the phosphate ion concentration in the sample was quantified by the molybdenum blue method. The result is shown in FIG.

<Example 5>
The diameter was adjusted in the same manner as in Example 3, except that 11.1 parts by weight of polymetaphenylene terephthalamide (Conex (registered trademark) manufactured by Teijin Techno Products Co., Ltd.) was added to 100 parts by weight of NMP to prepare a dope. A cylindrical shaped body having a length of 0.8 mm and a length of 2 mm was obtained. The dried molded body contains 92.5% by weight hydrotalcite and 7.5% by weight polymetaphenylene terephthalamide.

<Example 6>
Using the cylindrical shaped body obtained in Example 5, the phosphate ion adsorption test was carried out in the same manner as in Example 4. The result is shown in FIG.

<Comparative Example 1>
A fibrous molded body was prepared in the same manner as in Example 1 except that polyacrylonitrile was used as the polymer. The fibrous shaped body obtained by drying contains 80% by weight of hydrotalcite and 20% by weight of polyacrylonitrile.
In FIG. 3, the electron micrograph of the cross section of the obtained molded object is shown (500-times multiplication factor). According to the photograph, it can be seen that macrovoids are present in the molded body and hydrotalcite is supported. However, it is observed that the macrovoids are crushed and the entire fiber is crushed. FIG. 4 is an electron micrograph (3000 times) obtained by locally magnifying the polymer portion of FIG. 3. However, since the polymer is dense, fine pores cannot be confirmed at this magnification.

<Comparative example 2>
Using the fibrous molded body obtained in Comparative Example 1, a phosphate ion adsorption test was performed in the same manner as in Example 2. The result is shown in FIG.

<Comparative Example 3>
In Example 1, a fibrous molded body was obtained by the same operation except that hydrotalcite was not added to the dope. The obtained molded body is a fibrous molded body made of only aromatic polyamide. The same phosphate ion adsorption test as in Example 2 was performed using 0.625 g of the molded body. The result is shown in FIG.

  The molded body carrying the functional substance of the present invention is expected to be applied in various fields such as environmental purification such as air and water treatment, and chemical production. For example, the adsorption process can be efficiently performed by supporting an adsorbent that adsorbs VOC or the like as a functional substance.

2 is an electron micrograph (magnification 300 times) of a cross section of a fibrous molded body obtained in Example 1. FIG. 2 is a local enlarged electron micrograph (magnification 3000 times) of FIG. 1. 2 is an electron micrograph (magnification 500 times) of a cross section of a fibrous molded body obtained in Comparative Example 1. FIG. FIG. 4 is a local enlarged electron micrograph (magnification 3000 times) of FIG. 3. 3 shows the results of phosphate ion adsorption tests in Example 2, Comparative Example 2 and Comparative Example 3. It is the result of the adsorption test of the phosphate ion of Example 4 and Example 6. FIG.

Explanation of symbols

1 Hydrotalcite 2 Macrovoid 3 Polymer

Claims (11)

(1) A step of preparing a dope by adding 100 parts by weight of a polymer and 10 to 9700 parts by weight of a functional substance to 300 to 2400 parts by weight of a good solvent, and (2) coagulating the dope in a coagulating liquid. Process,
A method for producing a molded body comprising a porous material carrying a functional substance, wherein 50% by weight or more of the polymer is an aromatic polyamide. The process according to claim 1, wherein the aromatic polyamide is polymetaphenylene terephthalamide or polyparaphenylene terephthalamide. The production method according to claim 1, wherein the good solvent is N-methyl-2-pyrrolidone or dimethylacetamide. The production method according to claim 1, wherein the coagulation liquid is water. The method according to claim 1, wherein the functional substance is at least one selected from the group consisting of metal oxides, metals, inorganic substances, minerals, and synthetic resins. A porous molded article carrying a functional substance obtained by the production method according to claim 1. The molded article according to claim 6, comprising macrovoids separated by a polymer having pores. The molded article according to claim 6, wherein at least a part of the functional substance is coated with a polymer having pores. The molded body according to claim 7, wherein the longest part of the macro void is in the range of 1 to 150 µm. The molded product according to claim 8, wherein the longest portion of the pore diameter is in the range of 0.1 nm or more and less than 1 µm. The molded body according to claim 6, which is in the form of a lump, fiber, or plane.