JP2007254577A - Polyamide porous membrane and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a polyamide porous membrane that has a function as a scaffold for large cells, microorganism raise, catalyst, etc., by developing a honeycomb porous structure having a larger diameter on a porous membrane surface layer and to provide a method for producing the same. <P>SOLUTION: The method for producing a polyamide porous membrane comprises dissolving a polyamide in an alcohol solution of calcium chloride to prepare a solution of polyamide, allowing a container into which the solution is poured and which has an opening part at 0-40°C at 60-100% relative humidity for 3-5 days, evaporating a solvent contained in the solution, humidifying the solution, to form a gel-like thin film on the surface of the solution, adding water from the surface of the gel-like thin film to develop a three-phase structure of a solid phase-gel phase-solution phase on the gel-like thin film part in contact with water, taking out only the gel phase from the realized three-phase structure to the outside of the container, coating a substrate with the gel phase, immersing the substrate coated with the gel phase in water, to coagulate the coated membrane part. The surface layer has a function as a scaffold and the polyamide porous membrane is suitable for culture of large cells, microorganism raise, etc., and is produced in a relatively short time without wasting a polyamide. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a porous polyamide film having a honeycomb porous structure on the surface layer and having a scaffold function, and a method for producing the same.

The polyamide porous membrane can be easily prepared from a polyamide metal halide / alcohol solution through solution coagulation with moisture absorption.
In addition, as such a porous membrane, a honeycomb-like porous polymer thin film, its structure control, and application development to biological tissue engineering using this honeycomb-like porous polymer thin film are introduced (for example, non-porous). (See Patent Document 1). According to this Non-Patent Document 1, it is disclosed that a polymer thin film having regularly micrometer-sized pores can be formed by producing a porous film by a template method. Further, it is disclosed that by using a honeycomb-like porous polymer thin film produced by the above method as a cell culture substrate, cells can be promoted to form a tissue, and a cell aggregate having an ordered structure can be made. .
Organized by the Society of Polymer Science, Inc., edited by NTS Editorial Planning Department, “Polymer Frontier 21 Series 17 Specialty Polymers-Nano-level Material Design that Meets Required Properties”, First Edition, First Printing, Stock Company NTS, issued on May 29, 2003, p. 113-148

  However, in the porous polymer thin film shown in Non-Patent Document 1, only a honeycomb-structured film having a pore having a pore diameter in the range of 1 to 10 μm is introduced on its surface, and large cells and microorganisms that do not meet this pore diameter are introduced. It lacked the function as a scaffold for catalysts and the like.

An object of the present invention is to provide a porous polyamide membrane having a function as a scaffold for large cells, microorganism breeding, catalysts, etc. by producing a honeycomb porous structure having a large pore diameter on the surface of the porous membrane, and production thereof It is to provide a method.
Another object of the present invention is to provide a method for producing a porous polyamide membrane that can be produced in a relatively short time.

In the invention according to claim 1, the surface layer has a honeycomb porous structure with a pore diameter of 5 to 50 μm, the inside is formed in a three-dimensional network, and the pores inside the network have a continuous pore structure, It is a polyamide porous film characterized in that a network structure is formed in communication.
The invention according to claim 2 is the polyamide porous membrane according to claim 1, wherein the polyamide is polycaprolactam, polyhexamethylene adipamide or polyhexamethylene sebacamide.

The invention according to claim 3 includes a step of preparing a polyamide solution by dissolving polyamide in an alcohol solution of calcium chloride, a step of injecting the prepared polyamide solution into a container having an opening at the top, and a polyamide solution The container having the opening filled with the solution is allowed to stand for 3 to 5 days at a temperature of 0 to 40 ° C. and a relative humidity of 60 to 100% to evaporate the solvent contained in the polyamide solution, and A process of forming a gel-like thin film on the surface of the polyamide solution by absorbing the polyamide solution, and adding water from above the surface of the gel-like thin film formed on the surface of the polyamide solution in the container, A process of causing a solid phase-gel phase-solution phase to appear in the gel-like thin film part in contact with the added water, and a three-phase structure appearing on the surface of the polyamide solution inside the container. Porous polyamide including a step of taking out only the gel phase out of the container, a step of applying the taken out gel phase to the substrate, and a step of solidifying the applied membrane part by immersing the substrate coated with the gel phase in water It is a manufacturing method of a membrane.
The invention according to claim 4 is the invention according to claim 3, wherein the solution is prepared by aging for a period of 24 hours to 100 days after dissolving the polyamide in the alcohol solution of calcium chloride. It is a manufacturing method of a polyamide porous membrane.
The invention according to claim 5 is the method according to claim 3, wherein the water added from above the surface of the solution is pure water, an alcoholic aqueous solution or a metal chloride aqueous solution. is there.
The invention according to claim 6 is the method according to claim 3, wherein the polyamide is polycaprolactam, polyhexamethylene adipamide, or polyhexamethylene sebacamide.

  The polyamide porous membrane according to claim 1 of the present invention has a honeycomb porous structure with a surface diameter of 5 to 50 μm, the inside is formed in a three-dimensional network, and the pores inside the network have a continuous pore structure, A honeycomb porous structure and a network structure are formed in communication with each other.

  A manufacturing method according to claim 3 of the present invention includes a step of dissolving a polyamide in an alcohol solution of calcium chloride to prepare a polyamide solution, a step of injecting the prepared polyamide solution into a container having an opening on the top, and a polyamide. By leaving the container having the opening into which the solution is injected at a temperature of 0 to 40 ° C. and a relative humidity of 60 to 100% for 3 to 5 days, the solvent contained in the polyamide solution is evaporated. Further, water is added from above the surface of the gel-like thin film formed on the surface of the polyamide solution inside the container and the step of forming a gel-like thin film on the surface of the polyamide solution by absorbing the polyamide solution. The step of causing a three-phase structure of a solid phase-gel phase-solution phase to appear in the gel-like thin film portion in contact with the added water, and the three phases appearing on the surface of the polyamide solution inside the container The step of taking out only the gel phase out of the container, the step of applying the taken out gel phase to the base material, and the step of solidifying the applied film part by immersing the base material coated with the gel phase in water Including.

  Since the honeycomb porous structure formed in the surface layer of the polyamide porous membrane of the present invention is controlled within a pore diameter range of 5 to 50 μm, it serves as a scaffold for large cells, microbial breeding, catalysts, etc. suitable for this pore diameter. Can have a function.

The best mode of the present invention will be described below.
The polyamide of the present invention is either polycaprolactam (nylon 6), polyhexamethylene adipamide (nylon 66) or polyhexamethylene sebacamide (nylon 610). As the polyamide, a particulate or cotton-like one is used. First, this polyamide is dissolved in an alcohol solution of calcium chloride to prepare a polyamide solution. The alcohol solution is prepared by adding and mixing 15 to 30% by weight, preferably 19 to 25% by weight of calcium chloride with respect to 100% by weight of methyl alcohol or ethyl alcohol. When the concentration is 19 to 25% by weight, the polycaprolactam can be dissolved well and can take an ideal form with no excluded volume. Polyamide is added in an amount of 6 to 9% by weight based on 100% by weight of alcohol. When the amount of polyamide added is less than the lower limit, there is a problem that the film does not become a film but becomes tofu-like, and when the upper limit (25% by weight) is exceeded, the film becomes brittle. The polyamide solution may be used immediately after the polyamide is dissolved in an alcohol solution of calcium chloride for the production of a polyamide porous membrane. However, when it is aged for a period of 24 hours to 100 days, alcohol, calcium ions and polyamide The interaction with the amide group is stable and preferable.

  Next, a predetermined amount of the prepared polyamide solution is poured into a container (for example, a glass cylinder) having an opening at the top. A container having an opening into which a polyamide solution is injected is allowed to stand for 3 to 5 days at a temperature of 0 to 40 ° C. and a relative humidity of 60 to 100%. Do not put a lid or the like on the opening of the container to be left standing, but leave the upper part of the container open. In the standing, it is preferable that the container is housed in a desiccator kept at a constant temperature and humidity. If the temperature is lower than the lower limit, there is a problem that the humidity-controlled water in the desiccator freezes. If the temperature exceeds the upper limit, there is a problem that bubbles are generated in the polyamide solution. Further, when the relative humidity is less than the lower limit, there is a problem that it takes time to absorb moisture. A preferable temperature is 10 to 30 ° C, and a more preferable temperature is 25 ° C. Moreover, a preferable relative humidity is 80 to 100%, and a more preferable relative humidity is 100%. By allowing the polyamide solution to stand in the container, moisture absorption begins with evaporation of alcohol as a solvent from the surface of the solution. The standing of the container into which the polyamide solution has been poured varies depending on the temperature condition and the humidity condition, and the evaporation time and moisture absorption of the solvent change. It is preferable to place them. A gel-like thin film is formed on the surface of the polyamide solution by leaving the container into which the polyamide solution has been poured for the period.

  Next, as shown in FIG. 1, water 13 is added from above the surface of the gel-like thin film formed on the surface of the polyamide solution 12 inside the container 11. Here, the water 13 added to the gel thin film is not limited to pure water but may be an alcoholic aqueous solution or a metal chloride aqueous solution. Use of these aqueous solutions has an effect of affecting the size of the independent pores of the porous body and the number of meshes of the surface layer. When water 13 is added from above the surface of the gel-like thin film and after a while, a three-phase structure of solid phase 16 -gel phase 17 -solution phase 12 appears in the gel-like thin film portion in contact with the added water 13. Reference numeral 14 in FIG. 1 denotes an interface between water and a three-phase structure. In the gel phase 17 constituting the emerging three-phase structure, spinodal decomposition and phase separation occur at the lower and upper portions of the gel phase, respectively, and a porosity is formed at the upper portion. The container is housed in a desiccator kept at 100% relative humidity without adding water from the surface of the gel-like thin film formed on the surface of the polyamide solution inside the container. By keeping it, most of the polyamide solution can be made into a gel phase. The polyamide porous membrane of the present invention can also be produced using the gel phase that has appeared in this manner.

  Next, only the gel phase is taken out of the container out of the three-phase structure that appears on the surface of the polyamide solution inside the container. The extracted gel phase contains added water and a solution. Subsequently, the gel phase taken out from the container is applied to the surface of the base material at a desired thickness, for example, 0.02 to 0.5 mm, preferably 0.02 to 0.1 mm, using the flow of the gel. To do. As the substrate to be used, a material having a smooth surface and easily peeling the film formed in the subsequent process from the substrate surface is selected. Specifically, a material such as a slide glass that can be easily handled is suitable. The thickness of the gel phase applied to the substrate is not particularly limited, and the applied thickness can be adjusted according to the use of the porous membrane. After applying the gel phase to the substrate surface, the substrate coated with the gel phase is allowed to stand at room temperature and relative humidity of 40 to 60% for 10 seconds to 10 minutes, preferably 10 seconds to 1 minute. The reason why the base material coated with the gel phase is left is to metastabilize the interaction between the gel components.

  After standing, the substrate coated with the gel phase is immersed in water at room temperature. When the substrate is immersed in water, the applied gel phase solidifies and a honeycomb porous structure is formed on the surface layer of the gel phase. The substrate is immersed in water for 5 to 30 minutes, preferably 10 to 30 minutes. If the immersion time is less than the lower limit, the gel phase does not sufficiently solidify, and even if the upper limit is exceeded, the properties of the porous film obtained do not change. When the applied gel phase is solidified, the film formed by the solidification of the gel phase is peeled off from the substrate in water. The polyamide porous membrane of the present invention is obtained by washing the peeled coagulated membrane with water and drying it.

  The resulting polyamide porous membrane of the present invention has a honeycomb porous structure with a surface layer having a pore diameter of 5 to 50 μm, the inside is formed in a three-dimensional network, and the pores inside the network have a continuous pore structure, A honeycomb porous structure and a network structure are formed in communication. Since the honeycomb structure of the surface layer is controlled within the range of the pore diameter of 5 to 50 μm, it can have a function as a scaffold for large cells, microbial breeding, catalysts, etc. suitable for this pore diameter.

Next, embodiments of the present invention will be described in detail.
<Example 1>
20 g of calcium chloride was dissolved in 100 cc of methyl alcohol to obtain a methanol solution of calcium chloride. To this solution, 6.7 g of cotton-like polyhexamethylene adipamide was added and dissolved to prepare a polyhexamethylene adipamide solution. 32 cc of the polyhexamethylene adipamide solution prepared above was injected into a glass cylinder having an inner diameter of 30 mm and a height of 60 mm. The glass cylinder containing the solution was housed in a desiccator having a temperature of 30 ° C. and a relative humidity of 100%, and was left to stand for about 5 days. When the polyhexamethylene adipamide solution in the glass cylinder after standing was observed, the volume of the solution in the cylinder was reduced to about 20 cc, and a gel-like thin film was formed on the surface of the solution.
Next, about 10 cc of pure water at 30 ° C. was added from the surface of the gel-like thin film formed on the surface of the polyhexamethylene adipamide solution in the glass cylinder. After adding water from the surface of the gel-like thin film, after a while, a three-phase structure of solid phase-gel phase-solution phase appeared in the gel-like thin film portion in contact with the added water.

Next, only the gel phase was taken out of the container out of the three-phase structure that appeared on the surface of the polyhexamethylene adipamide solution in the glass cylinder. Subsequently, the gel phase taken out from the container was applied to the surface of the slide glass with an average thickness of about 0.05 mm. After the gel phase was applied to the surface of the slide glass, the slide glass coated with the gel phase was allowed to stand for 10 to 30 seconds at room temperature and a relative humidity of about 50%.
After being allowed to stand, the slide glass coated with the gel phase was immersed in water at room temperature and held for about 10 minutes to solidify the coated gel phase and form a honeycomb porous structure on the surface layer of the gel phase. When the applied gel phase solidified, the film formed by the solidification of the gel phase was peeled off from the slide glass in water. The peeled solidified film was washed with water and dried to obtain a polyhexamethylene adipamide porous film.

  Scanning Electron Microscope (SEM) photographs of the obtained polyhexamethylene adipamide porous membrane are shown in FIGS. FIG. 3 is a partially enlarged view of FIG. As apparent from FIGS. 2 and 3, it was confirmed that a honeycomb porous structure was formed on the surface layer of the obtained film. Further, the pore diameter of this honeycomb porous structure was in the range of about 10 to 20 μm. Further, it was confirmed from the pores of the honeycomb porous structure on the surface layer that the structure inside the film was in a three-dimensional network, and the honeycomb porous structure and the three-dimensional network were formed in communication.

<Example 2>
20 g of calcium chloride was dissolved in 100 cc of methyl alcohol to obtain a methanol solution of calcium chloride. To this solution, 6.7 g of polycaprolactam was added and dissolved to prepare a polycaprolactam solution. 32 cc of the prepared polycaprolactam solution was injected into a glass cylinder having an inner diameter of 30 mm and a height of 60 mm. The glass cylinder containing the solution was housed in a desiccator having a temperature of 30 ° C. and a relative humidity of 100%, and was left to stand for about 5 days. When the polycaprolactam solution in the glass cylinder after standing was observed, the volume of the solution in the cylinder was reduced to about 20 cc, and a gel-like thin film was formed on the surface of the solution.
Next, about 10 cc of pure water at 30 ° C. was added from the surface of the gel-like thin film formed on the surface of the polycaprolactam solution in the glass cylinder. After adding water from the surface of the gel-like thin film, after a while, a three-phase structure of a solid phase-gel phase-solution phase appeared in the gel-like thin film portion in contact with the added water.

Next, only the gel phase was taken out of the container out of the three-phase structure that appeared on the surface of the polycaprolactam solution in the glass cylinder. Subsequently, the gel phase taken out from the container was applied to the surface of the slide glass with an average thickness of about 0.05 mm. After the gel phase was applied to the surface of the slide glass, the slide glass coated with the gel phase was left for 10 to 30 seconds at room temperature and a relative humidity of about 50%.
After being allowed to stand, the slide glass coated with the gel phase was immersed in room temperature water and held for about 10 minutes to solidify the coated gel phase and form a honeycomb porous structure on the surface layer of the gel phase. When the applied gel phase solidified, the film formed by the solidification of the gel phase was peeled off from the slide glass in water. The peeled solidified film was washed with water and dried to obtain a polycaprolactam porous film.

  Scanning electron microscope (SEM) photographs of the obtained polycaprolactam porous membrane are shown in FIGS. FIG. 5 is a partially enlarged view of FIG. As apparent from FIGS. 4 and 5, it was confirmed that a honeycomb porous structure was formed on the surface layer of the obtained film. Moreover, the pore diameter of this honeycomb porous structure was in the range of about 20 to 50 μm. Further, it was confirmed from the pores of the honeycomb porous structure on the surface layer that the structure inside the film was in a three-dimensional network, and the honeycomb porous structure and the three-dimensional network were formed in communication. Compared to FIG. 2 of Example 1, the pore diameter of the honeycomb structure of the surface layer was large, and the internal three-dimensional network structure tended to be fine.

It is a figure which shows the three-phase structure of the solid phase-gel phase-solution phase in the manufacturing method of the polyamide porous membrane of this invention. 1 is a scanning electron micrograph of a porous film in Example 1. FIG. FIG. 3 is a partially enlarged photograph view of FIG. 2. 3 is a scanning electron micrograph of a porous film in Example 2. FIG. It is the elements on larger scale photograph of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Container 12 Polyamide solution 13 Water 14 Interface of water and three-phase structure 16 Solid phase 17 Gel phase

Claims (6)

The surface layer has a honeycomb porous structure with a pore diameter of 5 to 50 μm,
The inside is formed in a three-dimensional network, and the pores inside the network have a continuous pore structure,
A polyamide porous film, wherein the honeycomb porous structure and the network structure are formed to communicate with each other.   The polyamide porous membrane according to claim 1, wherein the polyamide is polycaprolactam, polyhexamethylene adipamide, or polyhexamethylene sebacamide. A step of preparing a polyamide solution (12) by dissolving polyamide in an alcohol solution of calcium chloride;
Injecting the prepared polyamide solution (12) into a container (11) having an opening at the top;
A container (11) having an opening filled with the polyamide solution (12) is allowed to stand for 3 to 5 days at a temperature of 0 to 40 ° C. and a relative humidity of 60 to 100%, thereby dissolving the polyamide. Forming a gel-like thin film on the surface of the polyamide solution by evaporating the solvent contained in the solution and absorbing the polyamide solution;
Water (13) is added from above the surface of the gel-like thin film formed on the surface of the polyamide solution inside the container (11), and the solid phase (in the gel-like thin film portion in contact with the added water (13) ( 16)-a step of causing a three-phase structure of gel phase (17)-solution phase to appear;
A step of taking out only the gel phase (17) out of the three-phase structure that appeared on the surface of the polyamide solution inside the container (11);
Applying the extracted gel phase (17) to a substrate;
Immersing the substrate coated with the gel phase (17) in water to solidify the coated membrane portion, and a method for producing a porous polyamide membrane.   The method for producing a porous polyamide membrane according to claim 3, wherein the solution is prepared by aging for a period of 24 hours to 100 days after the polyamide is dissolved in an alcohol solution of calcium chloride.   The method for producing a porous polyamide membrane according to claim 3, wherein water added from above the surface of the solution is pure water, an alcohol-based aqueous solution or a metal chloride-based aqueous solution. The method for producing a porous polyamide membrane according to claim 3, wherein the polyamide is polycaprolactam, polyhexamethylene adipamide, or polyhexamethylene sebacamide.