JP4747378B2 - Filter for sterilization - Google Patents

Description

    The present invention relates to a filter used in a ventilation facility for purifying indoor air in a house or an office building.

    Conventional ventilation equipment purifies indoor air by exchanging outside air and indoor air. Therefore, the filter is rarely used, and in the ventilation equipment, only a filter whose main purpose is to remove dust and the like contained in the outside air is used.

    Particularly in recent years, pathogenic viruses such as coronaviruses and influenza viruses present in the air have increased the incidence of disease and countermeasures have become necessary.

    On the other hand, the inventor of the present application developed a composite filter for purifying water and applied for it as PCT / JP02 / 13239. As described in that specification, ion exchange resins are effective in inactivating viruses and pathogenic bacteria.

Moreover, the nonwoven fabric can adsorb and remove bacteria such as cholera, shigella, and carbon.
Among the contents described above, inactivation of bacteria of the ion exchange resin is described in Non-Patent Document 1 below, and non-patent document 2 describes the adsorptivity of bacteria of the nonwoven fabric.
Journal of Japanese Society of Medical Instrumentation, 56: 499, 1986 Therefore, there is a possibility that bacteria in the air can be removed and inactivated by using an ion exchange resin or a non-woven fabric, or a combination thereof. Therefore, it is possible to purify indoor air by arranging them in a building ventilation system, and to prevent infection by bacteria and viruses.

    However, the ion exchange resin is generally in the form of particles, and when it is used as a filter, it is difficult to simplify it such as placing it in a container, and handling is inconvenient. In particular, it is difficult to make a structure that can be easily attached at any place by making it flat like paper or cloth, and can be easily replaced when the purification action is reduced.

    In addition, dust can be removed only with a nonwoven fabric, and even if a part of bacteria can be adsorbed, it is difficult to obtain sufficient purification and preventive effect on infection.

    The present invention provides a filter having a simple cloth shape, which can be easily placed and replaced in a ventilation facility, for example, and can inactivate bacteria, viruses and the like in the air.

The filter of the present invention is a 1-10% aqueous solution modified with carboxylic acid, which is a paste having a substance having an action of inactivating the nonwoven fabric against bacteria and viruses such as sulfate type or sulfonate type surfactants. After immersing in an aqueous solution of polyvinyl alcohol (hereinafter abbreviated as CA-PVA), the nonwoven fabric is heated to fix the paste.
CA-PVA used as a paste in the filter of the present invention retains the state where the paste is attached to the nonwoven fabric by heating after immersing the nonwoven fabric in the aqueous solution. Moreover, CA-PVA used as this paste has the effect | action which inactivates bacteria and viruses. The filter of the present invention utilizes this property of CA-PVA. That is, by immersing the nonwoven fabric in the CA-PVA aqueous solution as described above and heating it, the air-permeable property is maintained, and the CA-PVA is maintained in order to maintain the state where the paste is adhered to the nonwoven fabric for a long time. These bacteria and viruses can be used for a long time as a filter by the inactivation action. However, since the action of CA-PVA inactivating viruses and the like is weak, in the present invention, a substance that inactivates bacteria, viruses, etc., for example, a sulfate type or sulfonate type surfactant is mixed. Thus, a filter capable of sufficiently purifying air could be constructed by supplementing and strengthening the action of the paste to inactivate bacteria and viruses.

    Further, as a substance having an action of inactivating bacteria and viruses, aqueous dextran sulfate may be used in place of the sulfate type surfactant and the sulfonate type surfactant.

    That is, as another example of the filter of the present invention, the nonwoven fabric is immersed in an aqueous solution in which dextran sulfate is mixed with CA-PVA and then dried by heating.

    Another filter of the present invention was formed by attaching an ion exchange resin to the nonwoven fabric using an adhesive and heating the ion exchange resin so that the ion exchange resin did not easily fall down, and maintained air permeability. The virus and bacteria in the air can be removed by adhering the virus and bacteria to the ion exchange resin.

    In the filter of the present invention, as the paste aqueous solution, the ion-exchange resin is applied and heated after being immersed in the above-mentioned CA-PVA aqueous solution.

    The filter of the present invention thus prepared has a gas permeation property and has a non-woven fabric removal action such as dust, and is harmless by adsorbing harmful microorganisms such as viruses of ion exchange resin. It is possible to

    Therefore, by providing the filter of the present invention in a ventilation equipment such as a home ventilation fan or a building, it is possible to remove dirt from outdoor air, inactivate microorganisms, and improve the indoor environment. It becomes possible.

    The filter of the present invention ensures a certain air permeability, and therefore can be used in a ventilation facility or the like, and has an effect of inactivating bacteria and viruses mixed in the air.

    Next, as an embodiment of the filter of the present invention, a filter in which an ion exchange resin is adhered and fixed to a nonwoven fabric using a paste and a manufacturing method thereof will be described.

    An example of the filter according to the present invention is a non-woven fabric in which CA-PVA is used as a paste, and an ion exchange resin is applied to the non-woven fabric and then heated and fixed to form a cloth and has air permeability. A filter having a good bactericidal action is constructed.

    Next, a method for producing the filter of the present invention will be described with reference to the drawings.

    FIG. 1 is a diagram showing an outline of the steps of the production method of the present invention, (A) shows the whole, and (B) shows a hopper as viewed from below. As shown in FIG. 1, a non-woven fabric made of polyester fiber is used as the raw fabric roller 1, and after passing the non-woven fabric 2 through the paste aqueous solution tank 3, the cation exchange resin is introduced from the hopper 4 containing the cation exchange resin. It is applied, further heated and fixed at about 105 ° C. by the heater 5, and taken up by the take-up roller 6.

    Thus, the cloth-like filter 2 wound by the take-up roller 6 is used after being cut to a required size.

    In the method of the present invention, the above-mentioned synthetic resin fibers such as polyester are preferable as the raw material for the nonwoven fabric in terms of strength and other points. In addition, as the paste, after CA-PVA is fixed to the nonwoven fabric as described above, it is effective in practical use in order to maintain the state for a long time, and in itself is inactivated against viruses and the like. Since it has an effect | action, it is preferable. Here, the concentration of CA-PVA is preferably 1% to 10%. In particular, it is more desirable if the concentration of the CA-PVA aqueous solution is 3 to 7%. Moreover, although the modification degree of carboxylic acid is 1-4 mol%, polyvinyl alcohol with a high modification degree is desirable.

In the following carboxylic acid-modified polyvinyl alcohol (CA-PVA), the gelation of CA-PVA proceeds by heat treatment. Therefore, CA-PVA is gelled by heating to make it insoluble.

CA-PVA is represented by the following molecular formula.

    Here, if n = 500 or more, it is generally solid. However, n = 1000 is preferable in handling and the like.

    In the present invention, CA-PVA as a paste is used as an aqueous solution by dissolving n = 500 or more solid (flaked) CA-PVA in water. In practice, the value of n may be in the range of 500-2000.

Moreover, CA-PVA is easily soluble in water, and this insolubilization can be achieved by the following means. That is, it can be insolubilized by adding a small amount of sulfuric acid as a catalyst to 30% formaldehyde (CH ₂ O aqueous solution) and formalizing the OH group of the PVA portion by dehydration and cyclization as follows.

    Thereby, it is possible to insolubilize CA-PVA without heating, and to make it adhere and solidify to a nonwoven fabric.

In this case, as shown in FIG. 3, the apparatus does not need a heater, and the CH ₂ O aqueous solution tank 20 may be arranged after the CA-PVA aqueous solution tank 3. And after passing the two tanks 3 and 20, an ion exchange resin is apply | coated and it can fix to a nonwoven fabric with a paste, and can comprise a filter.

However, in this method, formaldehyde (CH ₂ O) remains on the nonwoven fabric even after commercialization, and it may be desorbed and the room may be exposed to formaldehyde odor.

    Moreover, the above-mentioned substances are used as the ion exchange resin. Further, it is more desirable to mix zeolite, silica, and alumina type acidic clay into the ion exchange resin.

    The surface of these zeolite, silica, and alumina-based acidic whiteness is acidic at pH 1-5. Therefore, mixing these with a cation exchange resin can prevent a decrease in the activity of the ion exchange resin.

    In this way, when zeolite, silica, or alumina-based acidic whiteness is mixed in the ion exchange resin, it may be mixed at a ratio of 95 to 5 with respect to the ion exchange resin 5 to 95.

    Further, the heating degree for fixing the paste may be in the range of 100 ° C to 120 ° C, but a temperature in the range of 105 ° C to 110 ° C is desirable.

    Here, the diameter of the ion exchange resin is around 1 mm. Therefore, if the non-woven fabric is directly adhered to the paste and heat-fixed, when it is used as a filter, it is possible to inactivate viruses and the like while maintaining the required air permeability. However, it may be preferable to make the particle diameter of the ion exchange resin smaller in order to increase the effect of inactivation or depending on the purpose and place of use of the filter. For example, it may be preferable that the ion exchange resin particle diameter is about 0.1 to 0.3 mm. In general, it is desirable to select and use within the range of 1 mm to 0.3 mm.

    For the above reasons, it is preferable to install a simple crushing mechanism between the time when the ion exchange resin falls from the hopper and is applied onto the nonwoven fabric.

    FIG. 2 shows another example of an apparatus for producing the filter of the present invention provided with this crushing mechanism.

    In FIG. 2, 1 is a raw fabric roller, 2 is a non-woven fabric, 3 is an aqueous paste solution, 4 is a hopper, 5 is a heater, and 6 is a take-up roller, and has substantially the same configuration as the apparatus shown in FIG.

    The apparatus shown in FIG. 2 is provided with a container 10 that covers the hopper 4, and is provided with, for example, stainless steel rollers 11 and 12 at the falling portion of the ion exchange resin from the hopper 4. The ion exchange resin passes between the rollers 11 and 12 and drops onto the nonwoven fabric. Here, the ion exchange resin is pulverized when passing between the rollers 11 and 12 to become an ion exchange resin having a small diameter, and is applied onto the nonwoven fabric.

In the apparatus shown in FIG. 2, the interval between the rollers 11 and 12 can be adjusted, and the ion exchange resin having a desired diameter can be applied by adjusting the interval.
2, after passing the nonwoven fabric 2 from the raw fabric roller 1 through the CA-PVA aqueous solution 3 which is an aqueous paste solution, the nonwoven fabric is immersed in the adhesive agent, the ion exchange resin from the hopper 4 is transferred to the roller. 11 and 12, and is applied onto the nonwoven fabric 2 as a powder having an appropriate particle size. Then, it heats with the heater 5, gelatinizes CA-PVA, insolubilizes, and winds up the filter of this invention with the winding roller 6. FIG.

    The filter of the present invention thus made has a small diameter of the ion exchange resin fixed to the nonwoven fabric by the insolubilization of the paste, and the ion exchange resin having a desired diameter according to the purpose of use is fixed. Can be obtained.

    Among the filters of the present invention described above, in the method for producing a filter containing an ion exchange resin, the ion exchange resin adheres to the paste, thereby ensuring that the ion exchange resin is heated and solidified. It is desirable to ensure integration with the non-woven fabric together with the paste so as to prevent peeling of the ion-exchange resin from the non-woven fabric during use as a filter and to keep the inactivating action of bacteria and viruses long. Therefore, it is preferable that the ion exchange resin is reliably attached to the paste using a pressure roller or the like immediately after the ion exchange resin is applied.

    In this case, if a means for pressure bonding with a roller is used, if the adhesive is not uniformly adhered to the nonwoven fabric, it can be made uniform. Furthermore, even if the application of the ion exchange resin is not uniform, the distribution on the nonwoven fabric can be made relatively uniform.

    As described above, when a method of pressing with a roller is used as a means for reliably mixing the ion exchange resin into the paste, it is considered that the air permeability of the nonwoven fabric after heat solidification is somewhat deteriorated. In order to prevent this, it is possible to ensure sufficient air permeability by slightly expanding the whole by applying an appropriate pulling force to the nonwoven fabric immediately after heating and solidifying with a heater.

    4A and 4B show an outline of an apparatus for realizing the above-described means, in which FIG. 4A is a view as seen from the side, and FIG. In FIG. 4A, as shown in FIG. 1 or FIG. 2, the steps up to the hopper 4 in the apparatus having the step of applying the ion exchange resin are omitted. That is, the ion exchange resin is applied at the position indicated by the arrow H after the nonwoven fabric is applied to a paste such as CV-PVA by the apparatus shown in FIG. Thereafter, the nonwoven fabric 2 is pressurized from above and below by rollers 21 and 22 as shown in FIG. 4, and as a result, adhesion of the ion exchange resin to the paste is ensured as described above. Thereafter, the nonwoven fabric 2 is heated through the heater 5 to solidify the paste, and the nonwoven fabric 2 and the paste are integrated. At the same time, the ion exchange resin and the paste are integrated into the nonwoven fabric. At the same time, the ion exchange resin and the paste are integrated into the nonwoven fabric. After that, for example, by arranging the transfer members 25, 26, 27 having needles as shown in FIG. 4B and sending them while applying force in the directions of the arrows Y1, Y2, sufficient air permeability is secured. I'm trying to wind up later. FIG. 4 shows an example, and the rollers 21 and 22 may be any means for completely adhering an ion exchange resin with a non-woven paste. Similarly, the transfer members 25, 26, and 27 may have any configuration as long as they are means for improving the air permeability of the filter.

    The process described above has been described by taking as an example the case where the filter of the present invention is manufactured by applying an ion exchange resin and heating.

    A filter to which the above-described sulfuric acid type surfactant or the like is attached can also be produced in the same process. In that case, since the said surfactant is powder, it mixes and disperse | distributes to the tank 3 which put the aqueous solution of CA-PVA which is a paste, and disperse | distributes the nonwoven fabric 2 which passed the tank 3 in the tank. By passing, the paste and the surfactant can be simultaneously adhered to the nonwoven fabric. And what is necessary is just to heat this nonwoven fabric by letting the heater 5 pass, and to gelatinize CA-PVA which is a paste agent.

    Therefore, the hopper for applying the ion exchange resin shown in FIG. 1 is not necessary.

The surfactant used here is preferably a sulfate type or a sulfonate type. As the sulfate type, the general formula [CH ₃ (CH ₂ ) _n —SO ₄ Na] of sodium sulfate is desirable. Generally, aliphatic sulfonates or sulfates are more preferable than aromatic sulfonates and sulfates. It is readily soluble in water, and aliphatic sodium sulfate is most desirable. As the sulfonate type, the general formula [CH ₃ (CH ₂ ) _n —SO ₃ Na] of sodium sulfonate is desirable, and particularly, sodium arifatic (aliphatic) sulfonate is most desirable.

    Similarly, when water-soluble dextran sulfate is used as a substance that inactivates bacteria and viruses, it may be mixed with the paste in the paste aqueous solution tank. Therefore, it is not necessary to use a hopper.

    As described above, the filter of the present invention uses CA-PVA as a paste to heat and fix a surfactant or ion-exchange resin that can inactivate bacteria and viruses to a nonwoven fabric, thereby providing stable adhesion. As a result, the filter is in the form of a cloth and can sterilize or inactivate bacteria.

The figure which shows the outline | summary of the apparatus used when manufacturing the filter of this invention. The figure which shows the outline | summary of the other example of the apparatus for manufacturing the filter of this invention. The figure which shows the outline | summary of the other example of the apparatus for manufacturing the filter of this invention. The figure which shows the outline | summary of the other example of the apparatus for manufacturing the filter of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Raw fabric roller 2 Nonwoven fabric 3 Paste solution tank 4 Hopper 5 Heater 6 Winding roller

Claims (1)

A filter formed by dipping a nonwoven fabric in a carboxylic acid-modified polyvinyl alcohol aqueous solution to which water-soluble dextran sulfate has been added, followed by drying by heating.

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