JP2000153114A - Production of deodorizing filter material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a deodorizing filter material having excellent deodorizing capacity and processability capable of fixing and supporting deodorizing particles on one deodorizing filter material having a sheet shape without substantially increasing pressure loss. SOLUTION: In producing a deodorizing filter material by arranging deodorizing particles on the surface of a hot melt nonwoven fabric and forming resin flocculation parts 13 to the contact parts of the hot melt nonwoven fabric with the deodorizing particles by heat treatment to form a web consisting of the resin flocculation parts 13 and connection parts 11, a first process for fixing and supporting deodorizing particles 17a with a relatively large particle size on the web and a second process for fixing and supporting deodorizing particles 17b with a relatively small particle size on the web are included.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deodorizing filter medium for filtering and cleaning particles contaminated with odor components, and more particularly to a method for producing a deodorizing filter medium having excellent deodorizing performance.

[0002]

2. Description of the Related Art Deodorizing filter media for removing odorous substances are:
In addition to the low pressure loss required as a characteristic of the filter medium as a whole, the function of particles composed of activated carbon and various chemical deodorants (hereinafter, collectively referred to as deodorized powder particles) supported on the filter medium is maximized. It is necessary to make use of it. To realize such a filter medium, the present applicant has filed Japanese Patent Application No.
No. 46215 proposes a deodorizing filter medium in which a deodorizing powder is supported on a nonwoven fabric made of a hot melt resin, and a technique for producing the same.

FIG. 1 is a view schematically showing a deodorizing filter medium by a schematic cross section for explaining a preferred embodiment of the above-mentioned technique. First, a deodorized powder 17 such as activated carbon is sprayed on the surface of a hot melt nonwoven fabric made of a thermoplastic hot melt resin. Next, a high-temperature fluid such as steam is applied to the nonwoven fabric in this state from the hot melt nonwoven fabric side. By such a heat treatment, the resin agglomerated portion 13 is formed in a portion where the hot melt nonwoven fabric and the deodorized powder 17 are in contact with each other, and the deodorized powder 17 is formed of the resin agglomerated portion 13 and the hot melt nonwoven. By the connecting portion 11 configured so that a part of the fiber component remains, the web 15 is fixed and held as a continuous component. Then, web 1
The laminate unit 19 is formed by removing the excess deodorized powder 17 not fixed to 5. FIG. 2 is a plan view of the laminated unit 19 viewed from the web 15 side, focusing on one of the deodorized powder granules 17 in this state. The constituent fiber having a relatively large fiber diameter is not cut even if it is plasticized and melted by the heat treatment, and forms a strong network structure as the connecting portion 11.

Then, the hot melt nonwoven fabric is again laminated on the laminated unit 19, the deodorized powder is sprayed, the heat treatment is performed, and the surplus powder is removed, whereby the deodorizing filter medium 21 shown in FIG. 1 is obtained. . In the deodorizing filter medium 21 having a plurality of such laminating units 19, by performing the above-described heat treatment with a high-temperature fluid, the gap between the deodorizing powder granules 17 adjacent to one laminating unit 19 is reduced. , A communication hole A extending between the other stacking unit 19 is formed. Therefore, by applying such a technique, it is possible to provide an excellent deodorizing filter medium having extremely low pressure loss.

[0005]

As is well known, the deodorizing efficiency can be improved by increasing the amount of deodorized powder particles provided in the filter medium and the probability of contact with it. In the filter medium obtained by the above-described conventional technique, by providing a plurality of lamination units, more deodorized powder particles per filter medium area can be supported and fixed. On the other hand, as a utilization form of the filter medium, a technique of increasing a contact probability of contaminated air with the filter medium by using a pleated filter folded into a predetermined shape is widely used. In this folding process, the smaller the thickness of the filter medium, the better the workability. Therefore,
The present inventor has applied the above-described conventional technique and focused on a technique for supporting a larger amount of deodorized powder particles on one lamination unit, and as a result of intensive studies, completed the present invention.
Therefore, an object of the present invention is to provide a deodorizing filter medium having a single sheet shape, which is capable of fixing a deodorizing powder at a high density, and which provides a manufacturing technique satisfying excellent deodorizing performance and processability. Is to do.

[0006]

In order to achieve this object, according to the method for producing a deodorizing filter medium according to the present invention, after the deodorizing powder is disposed on the surface of the hot-melt nonwoven fabric, the above-mentioned heat treatment is performed. In producing a deodorizing filter medium by forming a resin aggregated portion at a portion where the hot-melt nonwoven fabric and the above-mentioned deodorized powder and granules are in contact, and forming a web composed of the resin aggregated portion and the connecting portion, a relatively large particle size is used. After the first step of fixing and supporting the deodorized powder particles on the web, a second step of fixing and supporting the deodorized powder particles having a relatively small particle diameter on the web in this state is provided.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a manufacturing technique according to the present invention will be described below with reference to the drawings. In the drawings referred to in the following description, components having the same functions as those already described are denoted by the same reference numerals.

First, FIG. 3 is an explanatory view showing a web 15 obtained through the first step according to the present invention by a schematic cross section similar to FIG. First, a hot-melt nonwoven fabric is prepared to form the web 15 shown in FIG. As a hot melt resin capable of forming such a web, a thermoplastic polyamide-based resin, a thermoplastic polyester resin, a thermoplastic polyurethane resin, a polyolefin resin, a polyolefin-modified resin, or the like can be used alone or in combination. Examples of the polyolefin-modified resin referred to herein include an ethylene-vinyl acetate copolymer, a saponified ethylene-vinyl acetate copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-acrylic acid copolymer, and an ethylene-methacrylic acid copolymer. And ethylene-maleic acid copolymers, ionomer resins (thermosensitive resins obtained by adding a metal to an ethylene-methacrylic acid copolymer), and the like.
It is preferable to select and use a series of hot melt resins having a MI of 50 or more and 500 or less. In the case of a resin having an MI lower than the preferred range, the resin has low fluidity, so that a resin aggregated portion is hardly formed during the heat treatment, and the fixation of the deodorized powder may be incomplete. Furthermore, if the resin is higher than the above range, the fluidity at the time of the heat treatment is high, and the web strength is significantly reduced in the second step described later, which may impair the processability.

The hot melt nonwoven fabric for forming the above-mentioned web has an areal density of 10 to 30 g / m ^2.
Is preferred, and particularly preferably 15 to 25 g / m ² . If the areal density is smaller than these preferable ranges, the uniformity of the deodorized powder particles fixed to the web is impaired because the uniformity of the nonwoven fabric is lacking, and the efficiency of the deodorizing filter medium is reduced due to the leakage of odorous substances. You. Further, even if a hot-melt nonwoven fabric having a large areal density exceeding this preferred range is employed, no improvement in the fixing strength can be expected, resulting in an increase in pressure loss.

Further, the deodorized powder usable in the present invention includes various powders such as activated carbon, impregnated carbon formed by impregnating various chemical substances with the deodorized powder, and photocatalysts and granular catalysts utilizing redox action. Granules can be used in combination. In addition, the deodorized powder having “relatively large particle size” and “relatively small particle size” is not particularly limited as long as the particles have different particle sizes, but has an average particle size of 0.147 mm (10
It is preferable to employ two kinds of average particle diameters within a suitable range of 0 mesh or more and 1.65 mm (10 mesh) or less. If the particle size is smaller than the lower limit of the preferred range, the initial deodorizing efficiency can be increased, but the pressure loss is significantly increased. Further, when using a deodorized powder having a large average particle size exceeding the upper limit of this range, the deodorized filter medium becomes thick,
There is a tendency that workability during pleating is reduced.

[0011] On the surface of such a hot melt nonwoven fabric,
After arranging the deodorized powder 17a having a relatively large particle size, a web 15 including the resin aggregation portion 13 and the connecting portion 11 is formed by a heat treatment, and the web 15 is provided with the deodorized powder 17a.
Is fixed. In such a heat treatment, various conventionally known means such as a calender, a hot air heater, an infrared heater, heating by steam, a device for sandwiching and heating a fabric between a pair of endless belts facing each other, and the like are used. be able to. Thereafter, the state shown in FIG. 3 is obtained by removing the unfixed deodorized powder.

Next, on the web 15 in the state shown in FIG. 3, instead of the deodorizing powder 17a, a deodorizing powder 17b having a relatively small particle size is used, and the powder is sprayed, heated, and processed. By performing a second step such as removal of excess powder, a deodorizing filter medium 23 as shown in FIG. 4 is obtained. As the heat treatment in the second step, the same means as in the above-described first step can be employed, but for example, shrinking and cutting in a wet heat state, such as a thermoplastic polyamide resin or an ethylene-vinyl acetate copolymer resin. When a hot-melt nonwoven fabric made of a resin that is easy to use is used, heating in a dry heat state can be performed in the first step, and heating using steam can be performed in the second step. By adopting such a configuration, it is possible to leave a large number of connecting portions after the first step and to secure a fixing portion of the deodorized powder 17b in the second step.

When it is necessary to compensate for the decrease in strength due to the plasticization and melting of the hot-melt nonwoven fabric, a filter material conventionally used for collecting dust can be used for the support.

[0014]

EXAMPLES Hereinafter, the results of measuring the characteristics of a deodorizing filter medium manufactured according to a preferred embodiment of the present invention will be described with reference to preferred examples of the present invention. In the following description, specific conditions will be described by way of example to facilitate understanding of the present invention. However, the present invention is not limited to only these conditions, and any suitable design change and Deformations can be made.

[0015] As deodorizing filter medium according to the example embodiment, 100 mesh (149
commercially available activated carbon (manufactured by Kuraray Chemical Co., Ltd.) classified in the range of 36 μm to 36 mesh (420 μm) is sieved through a 60-mesh (250 μm opening) sieve, and the particle size of 100 to 60 mesh corresponding to the size under the sieve. A deodorized powder having a relatively small particle size (hereinafter referred to as “# 100/60”) and a deodorized powder having a relatively large particle size having a particle size of 60 to 36 mesh (hereinafter referred to as “# 60/60”). 36 ")
And reclassified. Then, a polyester, a spunbond surface density 30 g / m ² as a support, a thermoplastic polyamide-based surface density 20 g / m ² made of resin hot melt nonwoven fabric is laminated on the surface of the hot melt nonwoven fabric, above Deodorized powder having a relatively large particle size “# 60”
/ 36 ". Subsequently, the first step was performed by performing a heat treatment by applying steam of about 5 kg / cm ² from the support side for about 7 seconds. After that, the excess deodorized powder particles “# 60/36” which are not fixed are removed, and the deodorized powder particles “# 100 /
60 "was sprayed again, and after the heat treatment with steam described above and the removal of excess deodorized powdery granules"# 100/60 ", a deodorized filter medium according to the example in the state illustrated in FIG. 4 was obtained. The deodorizing filter medium according to this example has a thickness of 0.59 mm,
The total supported amount of the deodorized powder was 91 g / m ² .

Comparative Example 1 In Comparative Example 1, a commercially available activated carbon (manufactured by Kuraray Chemical Co., Ltd.) classified in the range of 100 mesh (149 μm) to 36 mesh (420 μm) was used without classification. A deodorizing filter medium was produced under the same conditions as in the example, except that the heat treatment was performed only once. The thickness of the deodorizing filter medium according to Comparative Example 1 is 0.5
It was 7 mm, and the carrying amount of the deodorized powder was 87 g / m ² .

Comparative Example 2 As Comparative Example 2, a deodorizing filter medium was prepared in the same manner as in Comparative Example 1, except that the deodorized powder having a relatively large particle size used in the examples, "# 60/36", was used. Prepared. The thickness of the deodorizing filter medium according to Comparative Example 2 was 0.59 mm, and the carried amount of the deodorizing powder was 82 g / m ² .

Comparative Example 3 As Comparative Example 3, except that the deodorized powdery granules “# 100/60” having a relatively small particle size used in the examples were used.
A deodorizing filter medium was produced in the same manner as in Comparative Examples 1 and 2. The thickness of the deodorizing filter medium according to Comparative Example 3 was 0.44 mm, and the carrying amount of the deodorizing powder was 47 g / m ² .

Hereinafter, the results of evaluating these deodorizing filter media will be described. The evaluation items were pressure loss, deodorizing efficiency, and breakthrough time of the deodorizing filter medium. First, the pressure loss measurement was performed according to a standard method, and 10 cm / sec, 30 cm / sec,
Air was blown at three levels of wind speed of 50 cm / sec, and each was determined by the pressure difference between upstream and downstream of the filter medium.

The deodorizing efficiency was measured using toluene as an odorant under the conditions of an initial concentration of 25 ppm and a wind speed of 14 cm / sec. In this measurement, 10 minutes after the start of the measurement, the test conditions were considered to have reached a steady state, and the initial condition was set.
Measurements were taken approximately every 10 minutes for up to 30 minutes. Result is,
The difference between the initial concentration (upstream concentration) and the downstream concentration after passing through the filter medium was divided by the initial concentration and calculated as a percentage.

Furthermore, the same conditions as in the above measurement of the deodorizing efficiency were used except that the initial concentration of toluene was 250 ppm and the wind speed was 0.7 cm / sec as the breakthrough time of the deodorizing filter medium. The point at which the toluene first exceeded 5% of the initial concentration was determined as the breakthrough time.

Table 1 summarizes the composition, pressure loss, deodorizing efficiency and 5% breakthrough time of each deodorizing filter medium, and FIG. 5 shows the change in deodorizing efficiency over time with the concentration on the downstream side as the vertical axis. FIG. 6 is a characteristic curve diagram showing elapsed time on the horizontal axis, and FIG. 6 is a characteristic curve diagram showing the change in deodorization efficiency leading to the 5% breakthrough in the same manner as in FIG. In FIG. 6, a dashed line is attached to 12.5 ppm corresponding to 5% breakthrough.

[0023]

[Table 1]

First, as can be seen from Table 1, the pressure loss of the deodorized filter medium according to the example was slightly higher than those of the comparative examples 1 to 3, but the difference was slight and substantially reduced. Became equivalent. As can be seen from Table 1 and FIG. 5, the filter media according to the examples outperformed the filter media according to Comparative Examples 1 to 3 at any measurement time, and the deodorization efficiency was excellent. Was confirmed. Further, when the 5% breakthrough time was compared, the life was about 10% longer than that of Comparative Example 2 which showed the best result among Comparative Examples.

From these series of evaluation tests, the deodorized powder having a predetermined particle size distribution is classified into at least two large and small particles. It has been clarified that an excellent deodorizing filter medium can be realized by supporting the odorant on a medium.

[0026]

As is apparent from the above description, by applying the technique of the present invention, the deodorizing filter medium having a single sheet shape can be used without substantially increasing the pressure loss. The body can be fixedly supported at high density,
It is possible to provide a deodorizing filter medium having excellent deodorizing performance and processability.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing a cross section of a deodorizing filter medium for explaining a conventional technique;

FIG. 2 is an explanatory view showing a plan view of a main part of a deodorizing filter medium for explaining the prior art and the present invention;

FIG. 3 is an explanatory view similar to FIG. 1 for explaining an embodiment of the present invention;

FIG. 4 is an explanatory diagram similar to FIG. 3 for explaining an embodiment of the present invention;

FIG. 5 is a characteristic curve diagram illustrating the deodorizing performance of the example, with the vertical axis indicating downstream concentration and the horizontal axis indicating elapsed time;

FIG. 6 is a characteristic curve diagram similar to FIG. 5 for explaining the breakthrough time of the example.

[Explanation of symbols]

11: connection part, 13: resin aggregation part, 1
5 : Web, 17: Deodorized powder, 17a: Deodorized powder (of relatively large particle size), 17b: Deodorized powder (of relatively small particle size), 19 : Stacking unit, 21 , 2
3 : Deodorizing filter medium.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) B01D 53/81

Claims (1)

[Claims] After disposing deodorized powder particles on the surface of a hot-melt nonwoven fabric, a heat treatment is performed to form a resin aggregation portion at a portion where the hot-melt nonwoven fabric and the deodorization powder particles are in contact with each other. In producing a deodorizing filter medium by forming a web composed of a connecting portion, a first step of fixing and supporting a deodorized powder having a relatively large particle diameter on the web, and a deodorizing process of a relatively small particle diameter on the web. And a second step of fixing and supporting the granules.