JPH10192624A - Pleats air filter of combined film materials of different types - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pleats air filter which has the performances of both an ion exchange filter and an active carbon fiber filter and also especially outstanding advantages in terms of pressure loss, weight and dust proofness by combining a nonwoven fabric or a woven fabric of a polymer fiber into which an ion exchange group is introduced through a radiation graft polymerization reaction. SOLUTION: An active carbon fiber 1 is folded together with a polymer fiber 2 into which an ion exchange group is introduced through a radiation graft polymerization reaction and then is laminated on the polymer fiber 2 in such a manner that the active carbon fiber 1 is sandwiched with the polymer fiber 2 from both faces to form an air filter. This air filter is of such a construction that a material to be adsorbed does not come into contact directly with the active carbon fiber 1. Therefore, it is unnecessary to mount a medium-performance filter or an electrostatic filter which has no organic material or ion-removing performance. In addition, it is possible to save a separator for securing a flow path with this pleats air filter, compared to the case in which both the active carbon fiber 1 filter and the polymer fiber 2 filter are individually installed. Consequently, a pressure loss can be minimized and the weight be reduced on the pleats air filter, compared to a conventional filter of this type.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air filter, and more particularly to a pleated air filter combining different types of membrane materials capable of adsorbing and removing contaminants contained in a gas, in particular, ion exchange substances.

[0002]

2. Description of the Related Art Recent advances in technology have led to the use of ion-exchanged nonwoven fabrics produced by the use of radiation-grafted polymerization reactions, and chemically adsorbed filters, and activated carbon fibers obtained by carbonizing cellulose, acrylic and lignin fibers. Adsorption filters that utilize phenol have been put to practical use. It is well known that activated carbon fibers and ion exchange fibers can efficiently adsorb and remove ions such as ammonia present in the air or ionic substances such as hydrofluoric acid and hydrochloric acid contained in mist. Further, the activated carbon fiber can adsorb and remove organic substances such as toluene, trichloroethane, cyclohexane, and methanol with high efficiency.

[0003] There is an increasing need for a filter for removing gaseous or mist-like ionic substances and organic gases from air circulating in a special space such as a clean room. The existing ion exchange filter and activated carbon filter are simply used in combination. In addition, of the exposed area of the interior material used in the clean room, the area of the filter material of the hepa or urpa filter is about 40 times the floor area. Boron causes malfunction of LSI products, and glass fiber hepa or ulpa filter media contains about 10% of boron oxide. Therefore, boron volatilization and contamination by boron fluoride due to reaction with HF occur. It is becoming more serious, and instead of a glass fiber hepa or urpa filter, a polyfluoroethylene fiber hepa or urpa filter or a polyfluoroethylene fiber electric filter is used.

[0004]

In a clean room such as a semiconductor factory, the concentration of total organic substances is very high, and the characteristic of activated carbon fiber is physical adsorption. It cannot be removed. Therefore, in order to design for a long life, the filling amount has to be increased, and this treatment also causes a pressure loss. In addition, a pleated filter usually uses a separator to secure a flow path. This does not contribute to removal and causes an increase in weight and pressure loss. Therefore, it is desired to reduce the number of separators as much as possible. In addition, since the fibers are activated by carbonization, the activated carbon fibers have a disadvantage of generating dust if they are bare.

[0005] The activated carbon fiber pleated filter can be prevented from generating dust by being wrapped with a medium-performance filter or an electrostatic filter.
In particular, dust generation during maintenance is serious, and further measures are required. In addition, for the prevention of contamination by boron trifluoride, even when looking at a polyfluoroethylene fiber hepa or urpa filter or a polyfluoroethylene fiber electric filter, there is no reaction with HF, and the boron itself cannot be removed. It has a weak point that if the degree of integration increases, it will be insufficient for countermeasures for trace amounts of boron.

[0006] In order to solve the above-mentioned various problems, the present invention has both the performance of an ion-exchange filter manufactured by using a radiation graft polymerization reaction and the performance of an activated carbon fiber filter, and combines these two types of filters. To provide a pleated air filter combining different types of membrane materials with particularly excellent pressure loss, weight, and dust-proofing properties.Also, an ion exchange filter manufactured using a radiation graft polymerization reaction, It is an object of the present invention to provide a pleated air filter combining different types of membrane materials, which has both the performance of an ethylene-based fiber hepa or urpa filter and a polypropylene electret filter and is free from contamination by boron trifluoride.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to provide a membrane material for filtering the atmosphere comprising activated carbon fibers and polymer fibers having ion-exchange groups introduced by radiation graft polymerization. Polymer fibers with ion-exchange groups introduced by radiation graft polymerization on the upstream and downstream sides of the membrane material are laminated and pleated together, or ion-exchange groups are formed by activated carbon fibers and radiation graft polymerization. The membrane material of the polymer fiber into which the activated carbon fiber and the ion exchange group are introduced by the radiation graft polymerization reaction is pleated alone and the ion exchange fiber layer is formed from the upstream side. , Activated carbon fiber layer, ion exchange fiber layer in series in order in order to be integrated by stacking different types of membrane material according to the present invention To be resolved by the pleated air filter.

Another object of the present invention is to provide an ion-exchange filter for producing a membrane material for filtering the atmosphere using a radiation graft polymerization reaction and a hepa- or urpa-filter made of polyfluoroethylene fiber or an electret filter made of polypropylene. And an ion exchange filter on the surface that is upstream with respect to the flow direction of the atmosphere,
Either a pleated or ulpa filter made of polyfluoroethylene fiber or an electret filter made of polypropylene is pleated together on the downstream side, or both of these membrane materials are pleated separately and ion exchange is performed from the upstream side. The solution is solved by a pleated air filter combining different kinds of membrane materials according to the present invention, which can be integrated by layering in series in the order of fiber, polyfluoroethylene fiber hepa or urpa filter or polypropylene electret filter layer. Is done.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the construction of the pleated air filter combining different membrane materials according to the present invention, a polymer fiber, an activated carbon fiber and a polyfluoroethylene fiber into which an ion exchange group has been introduced, a hepa or urpa filter or polypropylene The polymer fibers having ion-exchange groups introduced therein are made of a substrate composed of an organic polymer, for example, a polymer such as polyethylene or polypropylene, a natural polymer fiber such as cotton or wool, or a woven fabric. First, it is obtained by irradiating an ionizing radiation such as an electron beam or a gamma ray to generate many active sites, and chemically bonding a monomer having a sulfone group, a carboxyl group, an amino group or the like to the active site. it can.

The active sites generated by the above-mentioned irradiation with ionizing radiation are extremely reactive and are called radicals. By chemically bonding the above-mentioned monomers having free radicals to the active sites, the properties of the substrate can be improved. Separately, the properties of a monomer can be imparted. This technique is called a graft (grafting) polymerization method because the monomer is added to the substrate. the above,
By a radiation graft polymerization method, for example, as a monomer having an ion exchange group such as a sulfone group, a carboxyl group, and an amino group, for example, sodium styrenesulfonate, acrylic acid, and arylamine acid, etc. It is possible to obtain a nonwoven fabric-like ion exchanger having a significantly higher ion exchange rate than an ion exchanger called a bead ion exchange resin used for desalination, production of pure water, etc. As a monomer capable of introducing, for example, styrene, chloromethylstyrene,
After radiation-induced graft polymerization using glycidyl methacrylate, acrylonitrile, acrolein, or the like as a base material, an ion exchanger can be obtained in which the shape of the base material is maintained even if ion exchange groups are introduced.

As the activated carbon fiber, for example, a structure obtained by sintering activated cellulose fiber can be used. However, the activated carbon fiber is not limited to this. Good, as long as the pores are finer than the granular activated carbon and the specific surface area is large, any material including a commercial product may be used, and, like the granular activated carbon, an organic or inorganic sulfur compound. Adsorbs and removes oils and odor components. The present invention relates to a pleated air filter combining different types of membrane materials having both the performances of an ion exchange filter and an activated carbon filter manufactured using a radiation graft polymerization reaction. The activated carbon fiber 1 and the polymer fiber 2 into which an ion exchange group is introduced by a radiation graft polymerization reaction are co-folded, and the activated carbon fiber 1 is laminated so as to be sandwiched between the polymer fibers 2 from both sides and folded in a pleated shape. This shows a unit having an elliptical shape.

In the case of the pleated air filter using a combination of different kinds of membrane materials shown in FIG. 1, the structure is such that the substance to be adsorbed does not come into direct contact with the activated carbon fiber 1. And the need for mounting an electrostatic filter or the like is eliminated, and the separator for securing the flow path can be reduced as compared with the case where the filters of the activated carbon fiber 1 and the polymer fiber 2 are individually installed.
It enables low pressure loss and light weight as compared with existing filters of this type.

Although the pleated air filter having a combination of different kinds of membrane materials shown in FIG. 1 has the advantages as described above, the number of folds of the activated carbon fibers 1 and the polymer fibers 2 is the same. When the difference between the organic matter removal life of the polymer fiber 2 and the ion removal life of the polymer fiber 2 is extremely large,
Considering the case where this filter cannot be used effectively,
Further, when the permeability of the membrane material of the activated carbon fiber 1 and that of the polymer fiber 2 are significantly different, the number of folds cannot be freely changed, so that a pressure loss with respect to the processing air volume cannot be reduced. . A filter that solves the inconveniences considered in the filter of FIG. 1 is a filter having a shape shown in FIG. 2, in which a layer of a single-folded activated carbon fiber 1 is also a single-folded polymer having an ion exchange group introduced. It is configured to be laminated so as to be sandwiched between layers of the fibers 2 and folded into a pleated shape. With such a configuration, it is possible to provide a dustproof effect, and furthermore, the filter is effective. It facilitates the adjustment of pressure loss for use and processing air volume.

The present invention also provides a combination of different membrane materials having both the performance of an ion-exchange filter produced by utilizing a radiation graft polymerization reaction and a filter or an urpa filter made of a polyfluoroethylene fiber or an electret filter made of polypropylene. Pleated air filters are also pleated with an ion-exchange filter on the surface upstream of the air flow direction, and a polyfluoroethylene fiber hepa or urpa filter or polypropylene electret filter on the downstream surface. Integrally folded into a shape, or both of these membrane materials are pleated independently, and ion-exchange fiber, polyfluoroethylene-based hepa or urpa filter or polypropylene electret from the upstream side It is configured in an integrated shape by layering in the order of the filter layer in series, and by such a configuration, a conventional polyfluoroethylene fiber hepa or urpa filter, or only a polypropylene electret filter, Removal of boron, which was difficult to remove, is also facilitated.

[0015]

The present invention will be described below in more detail with reference to examples. Example 1 An existing pleated air filter made of activated carbon fiber alone and an ion-exchange fiber obtained by introducing a sulfone group into a polyethylene nonwoven fabric substrate by radiation graft polymerization reaction with activated carbon fiber made of cellulose were co-folded. As a result of comparing the amount of dust generated by the pleated type air filter combined with different types of membrane materials configured in combination with the shape while changing the linear velocity (LV), as shown in Tables 1 to 3 below, the pleated type different type membrane material of the present invention was obtained. In the case of a type air filter, dust having a particle size in the range of 0.1 to 0.3 microns is 1 to 3 (pieces / CM).
F) Only the range was recognized, significantly surpassing the performance of existing pleated air filters using activated carbon fibers alone. Even if activated carbon fibers were not used together with a dust-proof membrane such as a performance filter or an electrostatic filter, It was found that dust generation could be sufficiently suppressed.

[0016]

[Table 1]

[0017]

[Table 2]

[0018]

[Table 3]

Example 2 An ion exchange filter made of polyethylene into which a sulfone group was introduced and a cellulose activated carbon filter made of cellulose were separately mounted in two stages, and the same as in Example 1 without changing the weight of the filter medium. As a result of comparing the weight of the pleated air filter including the different types of membrane materials when the pleated type air filter was manufactured and installed, as shown in Table 4 below, only the frame material, the separator and the adhesive could be saved. ,
It has been recognized that the pleated air filter combining different types of membrane materials of the present invention is lighter than the conventional one.

[0020]

[Table 4]

Example 3 The materials used as the existing boron removal filter are tar pitch-based impregnated activated carbon fibers, and boron of an ion exchange filter produced by introducing a sulfone group into polyethylene fibers by a radiation graft polymerization reaction. As a result of comparison of the removal performance, as shown in the following Tables 5 and 6, it was recognized that the ion exchange filter greatly exceeded the performance of the attached activated carbon fiber in both the initial removal rate and the removal rate after 500 hours.

[0022]

[Table 5]

[0023]

[Table 6]

[0024]

According to the pleated air filter of the present invention, a substance to be adsorbed does not come into direct contact with the activated carbon fiber, so that organic substances and ions which are conventionally required to be installed are indispensable. Eliminates the need to install a medium-performance filter or electrostatic filter that does not have the removal performance of the filter, and secures the installation frame material and the channel compared to the case where the filters of activated carbon fiber and polymer fiber are installed individually. For this purpose, it is possible to reduce the pressure loss and weight as compared with existing filters of this type, and to make the activated carbon fiber layer a polymer fiber with ion-exchange groups introduced. This type of filter is improved because it has a dustproof effect because it is sandwiched between layers, making it easier to effectively use the filter and adjusting the pressure loss to the processing air volume. Rutokoro is large.

[Brief description of the drawings]

FIG. 1 shows a unit in which an activated carbon fiber and a polymer fiber into which an ion exchange group is introduced are formed into a co-folded shape, the activated carbon fiber is laminated so as to be sandwiched between the polymer fibers from both sides, and is pleated. FIG.

FIG. 2 is a drawing showing a unit in which a single-folded activated carbon fiber layer is laminated so as to be sandwiched by a single-folded polymer fiber layer into which an ion exchange group is also introduced, and is pleated. is there.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Activated carbon fiber 2 Polymer fiber which introduced ion exchange group

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B01D 53/81 ZAB

Claims (7)

[Claims] 1. A filter for removing contaminants contained in a gas by combining a nonwoven fabric or a woven fabric of a polymer fiber into which an ion exchange group has been introduced by a radiation graft polymerization reaction with another membrane material. Pleated air filter combining different membrane materials. 2. The pleated air filter according to claim 1, wherein the other membrane material is an activated carbon fiber. 3. The pleated air filter according to claim 1, wherein the other membrane material is an electret filter made of polypropylene. 4. The pleated air filter according to claim 1, wherein the other membrane material is a polyfluoroethylene fiber hepa or urpa filter. 5. The non-woven or woven fabric according to claim 1, wherein the ion-exchange group is selected from the group consisting of a cation alone, an anion alone and a combination of an anion and a cation. Pleated air filter combining different types of membrane materials. 6. A pleated air combining different membrane materials, wherein one of the different membrane materials selected from the group of the different membrane materials according to claim 2 is co-folded to enable integration. filter. 7. A heterogeneous material which can be integrated by folding any one of the heterogeneous film materials selected from the group of the heterogeneous film materials according to claim 2 and overlapping them in a series direction. Pleated air filter combined with membrane material.