JP2003251120A - Filter cartridge for precise filtering of fine particles/ metal impurities - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter cartridge for refining a medicinal liquid, capable of efficiently and simultaneously removing all of metal ions, metal colloid fine particles and fine granular impurities in the liquid to be filtered immediately before use (POU, point of use) by single operation. <P>SOLUTION: This filter cartridge is constituted of a fiber material, prepared by introducing an ion exchange group and/or a chelate group into an organic polymeric fiber base material, and a porous film material. In a further preferable embodiment, the filter cartridge is constituted of the fiber material, prepared by introducing the ion exchange group and/or the chelate group into the organic polymeric fiber base material, and the porous film material prepared by introducing a hydrophilic group into an organic porous film base material. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter cartridge which can be particularly preferably used for purification of pure water, chemicals or solvents used in the semiconductor industry. In particular, the present invention relates to trace metal impurities in the form of metal ions, metal colloids, and metal fine particles from chemical solutions such as ultrapure water for cleaning used in the semiconductor industry, photoresists, thinners or organic solvents for cleaning. The present invention relates to a filter cartridge capable of removing.

[0002]

2. Description of the Related Art In recent years, with the progress of semiconductor manufacturing technology, the densification of semiconductor elements and the miniaturization of line width have been rapidly progressing. Along with this, chemicals used in semiconductor manufacturing processes, such as photoresists, thinners, developers, strippers, product standards relating to the cleanliness of ultrapure water as a cleaning liquid, organic solvents, etc. Also, in recent years, extremely strict levels have been required for trace metal and metal ion concentrations. ITRS2000 (Inter
national Technology Roadmap for Semiconductors 200
According to (0), it is reported that the DRAM1 / 2Pitch level will be 130 nm in 2003 and 100 nm in 2005, that is, in the near future, it will be 1 / 2Pitch as an impurity contained in the chemical solution. It is expected that it will be required to remove fine particles of a size above the level. Further, as the metal concentration in the chemical solution used in the semiconductor manufacturing process, it is considered that in 2005, 2 × 10 ⁹ atoms / cm ² will be required as the cleanliness on the wafer surface. As can be seen from these facts, the progress of semiconductor manufacturing technology, product performance, and yield often depend on the progress of technology for removing fine particles and metals from used chemicals and cleaning, and thus far in the semiconductor industry. In view of the rapid development of the chemicals and reliable growth in the future, it is indispensable to achieve the above-mentioned levels with respect to the concentrations of fine particles and trace metals and metal ions in the chemicals used.

It is known that trace impurities contained in pure water for cleaning and solvents used in the semiconductor industry and the like exist in the form of fine particles and the form of free metal ions. . The impurities in the form of fine particles are, for example, polymer fine particles generated from polytetrafluoroethylene or the like used as a structural material in various members, originally contained in the supply liquid, or a pipe material in a supply line of the liquid. Fine particles such as metal oxides and metal hydroxides generated from joints and the like are included. Furthermore, the metal ions contained in the liquid may aggregate to form colloidal fine particles whose charge is neutralized. The colloidal fine particles are those in which metal ions are aggregated in a liquid to form a fine particle colloid having a large mass and a small charge density. In particular, an organic solvent contains metal impurities such as iron and aluminum. It is known that the formation of the colloidal fine particles is extremely likely to occur in the presence of such particles. It is known that the existence form of the colloidal fine particles largely varies depending on the conditions of the solution, such as the type of solvent or metal, pH, temperature, etc., and most metal colloids have a very large particle size distribution. Therefore, since the colloidal fine particles having a relatively large particle size have a small charge density, the metal impurities cannot be completely removed by ion exchange utilizing the electrostatic effect in the shape of the chemical liquid filter accompanied by the flow of the liquid.

As a technique for removing fine particles from various liquids, a method of mechanically filtering an object with various filter materials has been used. Furthermore, in recent years, a filter that removes fine particles and ions with high efficiency by applying a high zeta potential to the surface of the porous filtration membrane has been developed and used for various industrial applications. In particular, for high-precision microfiltration of a high-purity solution used in a semiconductor manufacturing process, it is important that the filter has a double capturing mechanism by mechanical filtration and electrostatic adsorption mechanism. This is because the mechanical trapping mechanism alone cannot trap particles having a pore diameter smaller than that of the porous membrane substrate, and iron oxide or aluminum oxide having a particle diameter of 0.01 μm or less dispersed in ultrapure water or an organic solvent. It is known that the mechanical filtration alone is not sufficient for capturing the colloidal fine particles. Similarly, the mechanism for trapping charged fine particles by the electrostatic adsorption mechanism alone is insufficient for trapping and removing coarse particles having a low charge density from the chemical solution in the microfiltration process under a high flow rate. This is because the moment of inertia of the coarse particles in the liquid flow exceeds the electrostatic moment between the colloidal particles and the charged functional groups. That is, in the microfiltration at a high flow rate of the high-purity solution used in the semiconductor element manufacturing process, in the filter medium having only the function of either mechanical filtration or electrostatic adsorption mechanism, the chemical cleaning ability is In the near future, there is a possibility that the required level of the semiconductor industry will be insufficient, and there has been an eager desire to develop a new technology.

Heretofore, as a technique for imparting electrostatic adsorption ability to a porous membrane, a cation charge controlling agent is used to impart a cation charge to a filter, and a cation charge adjusting agent is used to remove impurities from charged particles in an impurity filtering process in a passing liquid. A method for efficiently filtering and purifying a drug solution by generating a zeta potential in between has been reported. Examples of cationic charge control agents used for this purpose include polyamide polyamine epichlorohydrin cation resin, melamine-formaldehyde cation resin, and reaction product of dicyandiamide / monoethanolamine / formaldehyde. The feature of these technologies is that a cation charge controlling agent imparts a cation charge to the surface of the porous membrane, and a zeta potential is generated between the cation charge adjusting agent and the charged fine particles in the liquid passing therethrough, thereby efficiently removing fine particle impurities. Is to be done. Also,
A method of fixing and modifying polyamide or polyacrylic acid on the surface of the porous membrane using a crosslinking agent has also been proposed. However, the microfiltration membranes produced by these methods are
Although it has a good impurity removal performance, its impurity removal efficiency and metal trapping capacity were insufficient for use in the microfiltration of chemicals in the semiconductor manufacturing process which requires the aforementioned severe cleanliness.

[0006] It has also been proposed to provide a functional film capable of removing impurities such as metal ions and metal colloids by introducing an ion exchange group into the surface of a porous film having a capability of removing fine particles. As a method of introducing the ion exchange group, for example, a radiation graft polymerization method or the like can be used. However, if graft polymerization is performed on a porous membrane, the strength of the membrane base material will decrease. There were various problems such that cracking occurred at the fold when molded into a pleat shape, or the liquid flow rate decreased due to swelling of the monomer with the solvent in the pores. Therefore, the functional membrane in which the ion exchange group is introduced into the porous membrane by the graft polymerization method has a problem that the impurity removal efficiency is insufficient or the metal capturing capacity is extremely small. Furthermore, the morphology of the pores changes due to the permeation of the monomer into the membrane substrate, or the ion-exchange groups introduced by polymerization block the pores of the porous membrane, and the flow rate There was also the problem of changes.

On the other hand, in the field of gas filters and the like, a filter material having a function of efficiently removing gas molecules is produced by introducing an ion exchange group into a fiber material such as a woven fabric or a non-woven fabric by a graft polymerization method. Is being done. However, conventional non-woven fabrics and other fibrous materials used for such applications generally have a significantly larger opening than porous membranes and the like. Also,
Diffusion speed of metal ions and fine particles in liquid is slower than that of gas molecule. For this reason, even if a non-woven fabric conventionally used in the field of gas filters and the like is used as a liquid filter, satisfactory removal performance cannot be obtained at a liquid flow rate at which a liquid filter cartridge is generally used.
For the above reasons, in the field of liquid filter cartridges, fibrous materials such as non-woven fabrics are currently used as support materials when processing porous membranes into pleats.

[0008]

As described above,
In the existing technology, in the near future, there is currently no chemical solution purifier that simultaneously achieves impurity removal efficiency and product cleanliness that meet the requirements of the latest semiconductor device manufacturing processes. That is, at present, in the semiconductor industry, overcoming the disadvantages of existing separation functional materials, metal ions in liquid,
There is a strong demand for the development of a filter cartridge for chemical liquid purification, which can efficiently remove all of metal colloidal fine particles and fine particle-like impurities by a single operation immediately before use (POU, point of use).

[0009]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a fiber material having an ion exchange group and / or a chelate group introduced by graft polymerization and fine particles. By constructing a filter cartridge in combination with a porous membrane material having a removing ability, all of metal ions, metal colloid fine particles, and fine particle impurities existing as impurities in ultrapure water and chemical liquids can be extremely efficiently They found that they can be removed, and completed the present invention. In the filter cartridge according to the present invention, the ability to remove impurities is dramatically improved over the range predicted by those skilled in the art, as compared with the case where the graft-polymerized fiber material or the porous membrane material is used alone. Was found.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The constitution of the present invention will be described in detail below. The fiber base material that can be used as the base material for forming the fiber material, which is one of the constituent elements of the filter cartridge according to the present invention, is a polymer material fiber, or a woven or non-woven fabric which is an aggregate thereof. And the like can be preferably used. Polymer material Fiber materials include polyolefins such as polyethylene and polypropylene, P
TFE, polyvinylidene fluoride, halogenated polyolefin such as vinyl chloride, polyester such as polycarbonate, polyether, polyether sulfone, polysulfone, cellulose, and their copolymers, ethylene-tetrafluoroethylene copolymer Examples thereof include olefin copolymers typified by polymer and ethylene-vinyl alcohol copolymer (EVAL). The fiber material made of these materials has a large surface area, can increase the removal capacity of a trace amount of ions, is lighter in weight, and can be easily molded. Specific shapes of the fibers include long fibers and processed products, short fibers and processed products, and cut pieces thereof. Examples of the long fibers include continuous filaments, and examples of the short fibers include staple fibers. Processed products of long fibers and short fibers include various woven and non-woven fabrics produced from these fibers. Further, the woven / nonwoven material can be suitably used as a base material for radiation graft polymerization described later, and is lightweight and easily processed into a filter shape, so that the filter cartridge according to the present invention is formed. It is suitable as a fiber base material used for.

In the present invention, as a means for introducing an ion exchange group and / or a chelate group into the fiber base material, a graft polymerization method can be used, and a radiation graft polymerization method can be preferably used. In the radiation graft polymerization method, a desired graft polymer side chain is introduced onto the polymer main chain of the base material by irradiating the organic polymer base material with radiation to generate radicals and reacting with the graft monomer. Since it is a method capable of controlling the number and length of graft chains, and can introduce a polymer side chain into an existing polymer material of various shapes, for the purpose of the present invention. Ideal for use in. When the radiation graft polymerization method is used, the ion exchange groups and / or chelate groups are introduced into the polymer base material in the form of polymer side chains having these groups.

In the radiation graft polymerization method which can be preferably used for the purpose of the present invention, examples of radiation that can be used include α-ray, β-ray, γ-ray, electron beam and ultraviolet ray. Γ-rays and electron beams are suitable for use in the present invention. The radiation graft polymerization method includes a pre-irradiation graft polymerization method in which a graft base material is pre-irradiated with radiation and then brought into contact with a polymerizable monomer (graft monomer) to cause a reaction, and radiation in the coexistence of the base material and the monomer. There is a simultaneous irradiation graft polymerization method of irradiating
Either method can be used in the present invention. Further, by the method of contacting the monomer and the base material, a liquid phase graft polymerization method in which the base material is immersed in the monomer solution for polymerization, a gas phase graft polymerization method in which the base material is brought into contact with vapor of the monomer for polymerization, Examples of the method include an impregnated gas phase graft polymerization method in which a substrate is immersed in a monomer solution and then taken out from the monomer solution to carry out a reaction in a gas phase. Any method can be used in the present invention.

Woven / nonwoven fabrics, which are fibers and aggregates of fibers, are the most suitable materials for use as organic polymeric substrates for producing the filter material of the present invention, which retain the monomer solution. It is suitable for use in the impregnation gas phase graft polymerization method because it is easy to do. In addition, when a functional group such as an ion exchange group and / or a chelate group is introduced into the porous membrane substrate by the radiation graft polymerization method, the mechanical strength of the substrate is deteriorated. However, the fiber base material such as woven fabric / nonwoven fabric does not cause a decrease in mechanical strength even if a functional group such as an ion exchange group and / or a chelate group is introduced into the fiber base material by a radiation graft polymerization method. Therefore, it is possible to introduce a much larger amount of functional groups than in the case of using a porous membrane substrate.

In the present invention, examples of ion-exchange groups that can be introduced into the organic polymer fiber base material include sulfonic acid groups, phosphoric acid groups, carboxyl groups, quaternary ammonium groups, and tertiary or lower lower amino groups. And so on. Further, as the chelate group, a functional group derived from iminodiacetic acid and its sodium salt, various amino acid groups, for example, glutamic acid, aspartic acid, a functional group derived from lysine and proline, a functional group derived from iminodiethanol, Examples thereof include a dithiocarbamic acid group and a thiourea group.

In order to produce the fiber material constituting the filter cartridge according to the present invention, the above-mentioned polymerizable monomer having an ion exchange group and / or a chelate group is placed on the main chain of the fiber base material. A method of graft polymerization,
Although it does not have an ion exchange group and / or a chelate group per se, after graft-polymerizing a polymerizable monomer having a functional group convertible to these groups onto the main chain of the fiber substrate,
Any method of converting a functional group on the grafted polymer side chain into an ion exchange group and / or a chelate group can be adopted. As the polymerizable monomer having an ion exchange group that can be used for this purpose, for example, as the polymerizable monomer having a sulfonic acid group, styrenesulfonic acid, vinylsulfonic acid and their sodium salts, ammonium salts, etc. Acrylic acid, methacrylic acid, etc. as the polymerizable monomer having a carboxyl group; vinylbenzyltrimethylammonium chloride (VBTAC), dimethylaminoethyl methacrylate (DMAEMA), as the polymerizable monomer having an amine ion-exchange group Diethylaminoethylmethacrylate (DEAEMA), Dimethylaminopropylacrylamide (DMAPAA)
Etc. can be mentioned. Further, as the polymerizable monomer having no ion exchange group and / or chelate group per se, but having a functional group convertible to an ion exchange group and / or chelate group, glycidyl methacrylate, styrene, Acrylonitrile, acrolein, chloromethylstyrene, etc. can be mentioned. For example, a sulfonic acid group, which is a strongly acidic cation exchange group, can be introduced onto a side chain of a graft polymer by graft-polymerizing styrene onto a fiber base material and then reacting with sulfuric acid or chlorosulfonic acid to sulfonate the fiber. . Further, for example, after graft polymerization of chloromethylstyrene on a fiber base material, the base material is immersed in an aqueous iminodiethanol solution to introduce an iminodiethanol group, which is a chelate group, onto the side chain of the graft polymer. Further, for example, by graft-polymerizing p-haloalkylstyrene on a fiber substrate,
After replacing the halogen group on the side chain of the formed graft polymer with iodine, by reacting diethyl iminodiacetate to replace iodine with a diethyl iminodiacetate group, and further by hydrolyzing the ester group with an aqueous sodium hydroxide solution, An iminodiacetic acid group, which is a chelating group, can be introduced on the side chain of the graft polymer.

The fiber base material used in the present invention is
0.1 μm to 50 μm average fiber diameter and 0.1 μm to 10 μm
It is preferred to have an average pore size of 0 μm. Further, in a preferred embodiment of the present invention, the fiber substrate has a thickness of 0.1 μm to
It is preferable to have an average fiber diameter of 20 μm and an average pore diameter of 1 μm to 20 μm. In a further preferred embodiment,
The average fiber diameter of the fiber base material is more preferably 0.2 μm to 15 μm, further preferably 0.5 μm to 10 μm. The average pore size of the fiber base material according to the present invention is 1.0 μm to 10 μm.
Is more preferable, and 1.0 μm to 5 μm is still more preferable. In addition, in this invention, the average pore diameter of a fiber base material points out the value measured by the bubble point method. as mentioned above,
It has been found that when a filter cartridge is formed by using a fiber base material having a smaller average fiber diameter and smaller average pore diameter, the ability to remove various metal impurities is dramatically increased.

The filter cartridge according to the present invention is
The above-mentioned functional group-introduced fiber material and a porous membrane material are used in combination. Examples of the porous membrane material that can be used in the present invention include a porous polymer membrane or an existing porous molecular membrane containing an inorganic substance. Membrane materials include polyolefins such as polyethylene and polypropylene, halogenated polyolefins such as PTFE, polyvinylidene fluoride and vinyl chloride, polyesters such as polycarbonate,
Polyether, polyether sulfone, polysulfone,
Examples thereof include cellulose and olefin copolymers represented by copolymers thereof, ethylene-tetrafluoroethylene copolymers, ethylene-vinyl alcohol copolymers (EVAL), and the like.

The porous membrane material used in the present invention is 0.02 μm to several μm, more preferably 0.02 μm.
It is preferable to have an average pore size of ˜0.5 μm.
In addition, in the present invention, the average pore diameter of the porous membrane refers to a value measured by the same method as the method of measuring the average pore diameter of the fiber base material described above.

The filter cartridge according to the present invention is
It is characterized in that it is configured by combining the above-mentioned fiber material having a functional group introduced therein and a porous membrane material. By stacking these materials having excellent mechanical strength and accommodating them in the filter cartridge as pleats, a large membrane area can be accommodated in the filter cartridge. Therefore, the usable liquid flow rate range of the obtained filter cartridge can be used at a higher flow rate as compared with the disk type filter, and the removal performance of metal ions, metal colloid fine particles, etc. is hardly deteriorated even at a high flow rate. It was

In particular, by combining a fiber material having a functional group introduced therein with a porous membrane material according to the present invention to form a filter cartridge, iron ions and aluminum ions are aggregated in an organic solvent, resulting in a large mass and a small mass. Even for liquids that form colloidal particles of charge density,
All of the colloidal particles and other forms of particulate metal impurities as well as metal ion impurities can be efficiently removed by this filter cartridge. Although the exact mechanism is unknown, it is used in combination with a porous membrane and a graft fiber material to give the former mechanical filtration, that is, the role of removing colloidal fine particles having a particle size larger than its pore size, and the latter. The electrostatic adsorption, that is, the role of removing the colloidal fine particles having a small particle size and mass and a high charge density, allows the porous membrane and the graft fiber material to have a good role sharing, and each of them is independent. It is considered that the particle removal performance was surprisingly improved by covering a wide range from those having a small particle diameter to those having a large particle diameter as compared with the case of using.

According to the present invention, a fiber material having an ion exchange group or a chelate group introduced therein is housed in a filter cartridge in combination with a porous membrane material, so that a high capacity ion exchange group or chelate group is contained in the filter cartridge. Is introduced, it is possible to obtain a metal ion removing performance excellent in durability. Therefore, using a filter cartridge with exactly the same size and shape as the one used so far,
Not only fine particles but also free metal ions and colloidal fine particles can be removed from chemicals such as cleaning water and photoresists used in semiconductor manufacturing processes.
Further, by introducing an ion exchange group or a chelate group into a fibrous material such as a non-woven fabric which has been used as a support material for a porous membrane in a liquid filter cartridge, a structural burden is imposed on the main body of the semiconductor device manufacturing apparatus. Instead, it becomes possible to simultaneously remove the metal impurities from the fine particles by the same operation as the commonly used POU filtration step. Further, according to the present invention, it is not necessary to make any changes to the conventional filtration process, and it is very easy to apply to an actual device currently used in the semiconductor manufacturing process. The effect on industry is considered to be great. The filter cartridge according to the present invention can reduce metal impurities in the chemical liquid by being installed in the chemical liquid supply line of the semiconductor element manufacturing process in the middle of the route for circulating the chemical liquid tank. Further, by disposing the filter cartridge according to the present invention at POU in the chemical liquid supply line, metal impurities can be efficiently removed. Further, in this case, in addition to removing metallic impurities originally contained in the chemical liquid, it is possible to deal with contamination from a transfer route such as a pipe or a joint.

Furthermore, in another embodiment of the present invention, a functional group such as an ionic hydrophilic group or a nonionic hydrophilic group can be introduced into the porous membrane material contained in the filter cartridge. In this case, when an excessively large amount of functional groups are introduced into the porous membrane material by graft polymerization or the like, the physical / mechanical strength of the porous membrane is deteriorated as described above, or a monomer membrane base material is used. There is a problem that the morphology of the pores changes due to permeation into the interior, or the ion exchange groups introduced by polymerization block the pores of the porous membrane, which causes a change in the flow rate. , Not preferable. However, by introducing an appropriate amount of a functional group such as a hydrophilic group into the porous membrane by a graft polymerization method or the like such that these problems do not become apparent, the wettability of the porous membrane with the liquid is improved and the filter is used. The generation of bubbles is suppressed, and when an ionic hydrophilic group is introduced as the hydrophilic group, the porous membrane itself is provided with some ion removal performance, which is preferable. In addition, since fine particles such as metal oxides and metal hydroxides in the liquid are usually negatively charged, if an ionic hydrophilic group having a positive charge is introduced into the porous membrane material, these fine particles in the liquid will be It is expected to be electrostatically adsorbed and removed by the ionic hydrophilic groups on the porous membrane.

The functional groups that can be introduced into the porous membrane material for such purposes include sulfonic acid groups, phosphoric acid groups, carboxyl groups, quaternary ammonium groups, and lower tertiary amino groups. Ionic hydrophilic groups, amide groups,
A nonionic hydroxyl group such as a hydroxyl group can be mentioned.
As a method of introducing the polymer side chain containing these hydrophilic groups onto the main chain of the porous membrane material, a method of graft-polymerizing a polymerizable monomer having a hydrophilic group (monomer) onto the main chain, and itself Does not have a hydrophilic group, but after graft-polymerizing a polymerizable monomer capable of introducing a hydrophilic group onto the main chain,
The method of introducing a hydrophilic group onto the grafted polymer side chain can be employed. As the polymerizable monomer having an ionic hydrophilic group, for example, as a polymerizable monomer having a sulfonic acid group, styrenesulfonic acid, vinylsulfonic acid and their sodium salts, ammonium salts, etc .; Acrylic acid, methacrylic acid, etc. as monomers; vinylbenzyltrimethylammonium chloride (VBTAC), dimethylaminoethyl methacrylate (DMAEMA), diethylaminoethyl methacrylate (DEAEMA) as polymerizable monomers having an amine-based ionic hydrophilic group , Dimethylaminopropyl acrylamide (DMAPAA) and the like; Further, for example, as the polymerizable monomer having an amide group which is a nonionic hydrophilic group, acrylamide, dimethylacrylamide, methacrylamide, isopropylacrylamide and the like can be mentioned. 2-hydroxyethyl methacrylate etc. are mentioned as a polymerizable monomer which has a hydroxyl group which is a nonionic hydrophilic group. Further, as the polymerizable monomer which does not have these hydrophilic groups per se but can introduce these hydrophilic groups, glycidyl methacrylate, chloromethylstyrene, vinyl acetate and the like can be mentioned. As a method of introducing a hydrophilic group after graft-polymerizing these polymerizable monomers, a known method can be adopted. For example, after graft-polymerizing vinyl acetate, a base material is mixed with a caustic soda / methanol mixed solution. A hydroxyl group can be introduced onto the side chain of the polymer by heating and hydrolyzing. As a means for introducing these functional groups into the porous membrane material, the graft polymerization method as described above, particularly the radiation graft polymerization method can be preferably used.

Further, in the present invention, when introducing a functional group into the porous membrane material by graft polymerization, it is desirable that the above-mentioned various problems should not be manifested, so that the grafting amount is about 5% to 50%. It is desirable to set the rate.

[0025]

The filter cartridge according to the present invention comprises a fiber material into which a functional group such as an ion exchange group is introduced,
By arranging in combination with the porous membrane material, a large amount of functional groups are introduced into the fiber material, and thus the cartridge of the exact same size and shape as before, and the fine particle removal that the conventional porous membrane filter has While maintaining the performance, it dramatically improves the removal of fine charged particles, metal ions, metal colloid fine particles and the like which could not be achieved by only the porous membrane filter.

[0026]

The present invention will be described in more detail with reference to the following examples, which show one specific example of the present invention.
The present invention is not limited by these descriptions.

Example 1 Preparation of Filter Cartridge of Sulfonic Acid Type Nonwoven Fabric / Non-Grafted Porous Membrane Nonwoven Fabric Made of Polyethylene Fiber (DuPont, trade name Tyvek: average fiber diameter 0.5 to 10 μm, average pore diameter 5)
μm (value measured by bubble point method), basis weight 6
83 g (5 g / m ² , thickness 0.17 mm) was irradiated with an electron beam of 150 kGy in a nitrogen atmosphere. The irradiated non-woven fabric was impregnated with styrene, placed in a glass container, decompressed by a vacuum pump, and then graft-polymerized at 50 ° C. for 3 hours. The grafted non-woven fabric was taken out and treated in toluene at 60 ° C. for 3 hours to remove the homopolymer. Further, the non-woven fabric was washed with acetone and then dried at 50 ° C. for 12 hours to obtain 136 g of a styrene-grafted non-woven fabric. The graft ratio was 64%.

The styrene-grafted non-woven fabric obtained was mixed with a chlorosulfonic acid / dichloromethane mixture (weight ratio 2: 9).
8), and the sulfonation reaction was carried out at 0 ° C. for 1 hour.
The non-woven fabric is taken out, washed successively with methanol / dichloromethane mixture (weight ratio 1: 9), methanol and pure water and dried to give a thickness of 0.27 mm and an ion exchange capacity of 3
A sulfonic acid type nonwoven fabric of 28 meq / m ² was obtained.

The sulfonic acid type nonwoven fabric (effective width 220 mm) prepared above and ultra high molecular weight polyethylene (molecular weight 1
With a thickness of 100 mm, a pore size of 0.2 μm, and a flat film-like porous film (effective width 220 mm) having a porosity of 60.0% and having a height of 14 mm and a number of peaks of 145. Pleats were made. The effective area of this pleated laminate sheet was 0.89 m ² . This pleated laminated sheet,
Filter inner core made of high-density polyethylene (diameter 46m) with the non-woven fabric on the outside and the porous membrane on the inside.
m, length 220 mm), inserted into a filter cage (inner diameter 76 mm, height 220 mm), and sealed by a heat-welding method using bottom and top caps to obtain the high-performance filter cartridge 1. Formed.

Example 2 Preparation of Filter Cartridge of Sulfonic Acid Type Nonwoven Fabric / Carboxylic Acid Type Porous Membrane The same as Example 1 for 39 g of the same ultra high molecular weight polyethylene porous membrane used in Example 1. The electron beam was irradiated under the conditions of. Acrylic acid / water / methanol mixture (weight ratio 10:45:45) was placed in a glass container, and the above-mentioned irradiated porous membrane was placed therein, and the pressure was reduced by a vacuum pump, then at 50 ° C. for 2 hours. Graft polymerization was performed. The grafted porous membrane was taken out, washed with pure water three times to remove the homopolymer, and further dried at 50 ° C. for 12 hours to obtain 44 g of an acrylic acid-grafted porous membrane. Graft ratio is 12%, thickness is 0.
It was 11 mm.

Using the sulfonic acid type nonwoven fabric (effective width 220 mm) prepared in Example 1 and the acrylic acid-grafted porous membrane (effective width 220 mm) obtained above, Example 1
Similarly to the above, a pleat-shaped laminated sheet having a height of 14 mm and a number of peaks of 145 was formed (effective area: 0.89 m ² ), and a high-performance filter cartridge 2 was formed by the same filter inner core and filter cage as in Example 1.

Example 3 Preparation of Filter Cartridge of Sulfonic Acid Type Nonwoven Fabric / Carboxylic Acid Type Porous Membrane Nonwoven fabric made of polyethylene fiber (trade name: OX8901, manufactured by Japan Vilene Co .: average fiber diameter 20 to 30 μm, average pore diameter 120 μm (bubble point Value (measured by the method), a basis weight of 66 g / m ² , and a thickness of 0.32 mm) of 100 g were irradiated with an electron beam under the same conditions as in Example 1. The irradiated non-woven fabric was impregnated with styrene, placed in a glass container, decompressed by a vacuum pump, and then graft-polymerized at 50 ° C. for 3 hours. The grafted non-woven fabric is washed in the same manner as in Example 1,
By drying, the styrene graft nonwoven fabric 202
got g. The graft ratio was 102%. The obtained styrene-grafted nonwoven fabric was sulfonated, washed and dried in the same manner as in Example 1 to obtain a sulfonic acid type nonwoven fabric having a thickness of 0.9 mm and an ion exchange capacity of 635 meq / m ² .

The sulfonic acid type nonwoven fabric obtained above was laminated with the acrylic acid-grafted porous membrane prepared in Example 2 to prepare a pleat-like laminated sheet having a height of 14 mm and a number of peaks of 90 (effective area 0). .55m ² ). Using this pleated laminated sheet, a high-performance filter cartridge 3 was formed in the same manner as in Example 1.

Example 4 Liquid Permeation Test A liquid permeation test was conducted using each of the high-performance filter cartridges 1, 2 and 3 produced in Examples 1 to 3 above. As a test liquid, 5.0 L / m of pure water containing 200 ppb of iron
When the concentration of iron in the effluent was measured by passing through at a flow rate of in to 20 L / min, the iron concentration in the effluent in the range of this flow rate was 0.6 to 1.9 pp for the filter cartridge 1.
b, the filter cartridge 2 is 0.02ppb-0.04
ppb, filter cartridge 3 is 0.9 ppb to 2.2 pp
The values fell to the range of b, and all showed good iron impurity removal performance.

Example 5: Liquid Permeation Test of Isopropyl Alcohol A liquid permeation test was conducted on the filter cartridge 1 in the same manner as in Example 4 except that isopropyl alcohol containing 200 ppb of iron was used as the test liquid. The iron concentration in the effluent decreased to the range of 0.2 ppb to 0.6 ppb, and showed good iron impurity removal performance for isopropyl alcohol as well as pure water.

Example 6: Comparison of defoaming properties A defoaming test was carried out using the high performance filter cartridge 1 prepared in the above Example 1 and the high performance filter cartridge 2 prepared in Example 2, respectively. A pump, filter cartridge 1 or 2, and a dynamic light scattering type particle counter were connected in series in this order to a circulation tank filled with 42 L of buffered hydrofluoric acid, and the liquid was circulated at a flow rate of 16 L / min. After the circulation was started, the number of microbubbles in the effluent from the filter cartridge was measured with a particle counter. The results are shown in Fig. 1.
In the experiment using the filter cartridge 1 of the sulfonic acid type non-woven fabric / non-grafted porous membrane, micro bubbles were observed in the effluent. On the other hand, in the experiment using the filter cartridge 2 of the sulfonic acid type nonwoven fabric / carboxylic acid type porous membrane, the number of microbubbles was greatly reduced by the short-time circulation. This is because by using a carboxylic acid group grafted as the porous membrane constituting the filter cartridge, good wettability of water on the surface of the porous membrane can be obtained, and good defoaming property by short-time liquid circulation. It is believed that this is because

Example 7 Liquid Permeation Test A liquid permeation test was conducted using the high performance filter cartridge 3 produced in Example 3 above. As test liquid, pure water of pH 4 containing 2.2 ppb of iron is 5.0 L / min to 20 L / min
When the concentration of iron in the effluent was measured by passing the solution at a flow rate of, the iron concentration in the effluent was 0.0
It fell to the range of 4 ppb to 0.06 ppb, and showed good performance for removing iron impurities. Similarly, 5.0 L / m of pure water of pH 7 containing 4.6 ppb of aluminum ions was used as a test solution.
When the concentration of aluminum in the effluent was measured by passing through at a flow rate of in to 20 L / min, the concentration of aluminum in the effluent was 0.03 ppb to 0.05 ppb in this range of flow rate.
, Which indicates a good aluminum impurity removal performance.

Comparative Example 1 Removal of Iron from Isopropyl Alcohol Using a Porous Membrane Filter Cartridge The ultra high molecular weight polyethylene porous membrane used in Example 1
As a supporting material, a polyethylene fiber non-woven fabric before grafting used in Example 1 (manufactured by DuPont, trade name Tyvek)
Was used to form a pleated laminated sheet in the same manner as in Example 1, and a filter cartridge A was formed in the same manner as in Example 1. Using this filter cartridge A, an isopropyl alcohol flow test was conducted under the same conditions as in Example 5, and the iron concentration in the effluent was 4.0 ppb.
The range was ˜13.1 ppb.

Comparative Example 2 Removal of Iron from Isopropyl Alcohol Using Sulfonic Acid Nonwoven Fabric The sulfonic acid nonwoven fabric prepared in Example 1 and the polyethylene fiber nonwoven fabric before grafting used in Example 1
The sheets were overlapped to form a pleated laminated sheet having the same size as in Example 1, and a filter cartridge B was formed in the same manner as in Example 1. This filter cartridge B
When an isopropyl alcohol liquid permeation test was conducted under the same conditions as in Example 5, the iron concentration in the effluent was 36.
It was in the range of ppb to 65 ppb.

[Brief description of drawings]

FIG. 1 is a graph showing the experimental results of Example 6.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B01J 47/12 B01J 47/12 G C02F 1/28 C02F 1/28 F 1/42 1/42 A C08J 5 / 20 101 C08J 5/20 101 CER CER CEZ CEZ // C08L 101: 00 C08L 101: 00 (72) Inventor Kunio Fujiwara 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa Stock company Ebara Research Institute (72 ) Inventor Satoru Takeda 4-2-1 Honfujisawa, Fujisawa-shi, Kanagawa Inside the EBARA Research Institute Co., Ltd. (72) Inventor Yukio Hashimoto 1-34 Mita International Building, Minato-ku, Tokyo Mita International Bill Japan Microlith In-house (72) Inventor Eriko Usui 1-4-2 Mita, Minato-ku, Tokyo Mita International Building Japan Microlith Co., Ltd. (72) Inventor Mitsuhiro Toshi Mita Kokusai Building, 1-4-2, Mita, Minato-ku, Tokyo F-term (reference) within Japan Microlith Corporation 4D017 AA01 AA06 BA12 CA13 CA17 CB05 DA01 EA05 4D019 AA03 BA13 BB03 BB08 BB10 BC04 BC13 BD01 CA02 CA03 CB03 CB06 DA03 4D024 AA03 AB15 AB16 BA17 BA18 BB02 BC01 CA04 DB04 4D025 AA04 AB01 AB20 AB22 BA08 BA27 BB01 4F071 AA02 FA04 FA05 FA06 FA07 FA08 FA09 FA10 FC11 FD04

Claims (6)

[Claims] 1. A filter cartridge comprising a fiber material having an ion exchange group and / or a chelate group introduced into an organic polymer fiber base material and a porous membrane material. 2. A constitution comprising a fiber material in which an ion exchange group and / or a chelate group is introduced into an organic polymer fiber substrate and a porous membrane material in which a hydrophilic group is introduced into an organic porous membrane substrate. The filter cartridge is characterized by being. 3. The radiation graft polymerization method introduces a polymer side chain having an ion exchange group and / or a chelate group onto the main chain of the organic polymer fiber base material, and the hydrophilic group of the organic porous film base material main chain. The filter cartridge according to claim 1 or 2, which is introduced on a chain. 4. The filter cartridge according to claim 1, wherein the fiber base material is a woven fabric or a non-woven fabric. 5. The ion exchange group is selected from a cation exchange group selected from a sulfonic acid group, a phosphoric acid group and a carboxyl group, or a quaternary ammonium group, a primary, secondary or tertiary lower amino group. Selected from anion exchange groups, the chelate group is selected from iminodiethanol group, iminodiacetic acid group, dithiocarbamic acid group, thiourea group, hydrophilic group is a sulfonic acid group, phosphoric acid group, carboxyl group, quaternary ammonium group, 5. An ionic hydrophilic group selected from a tertiary amino group, a secondary amino group and a primary amino group, or a nonionic hydrophilic group selected from an amide group and a hydroxyl group. The described filter cartridge. 6. A porous membrane having an average pore diameter of 0.02 μm to
The filter cartridge according to claim 1, which has a thickness of 1.0 μm.