JP2015139720A - Filter material for deodorization filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter material for a deodorization filter capable of sufficiently exhibiting deodorization performance, and excellent in a pressure loss and a dust holding amount, while enhancing adhesiveness and rigidity.SOLUTION: The filter material is composed of a laminate structure of sandwiching an adsorption layer composed of an adsorbent and an adhesive between base material layers. In the filter material for the deodorization filter, one layer of the base material layer is composed of resin-processed thermal bond nonwoven fabric, and another one layer of the base material layer is composed of a laminate sheet of integrally laminating nonwoven fabric composed of heat-seal system long fiber and electret needle punch nonwoven fabric by a needle punch, and the adsorption layer and the nonwoven fabric composed of the heat-seal system long fiber of the laminate sheet are adjacently laminated by a heat-seal.

Description

  The present invention relates to a filter medium for a deodorizing filter having excellent adhesiveness and rigidity, as well as low pressure loss and high dust holding capacity.

  In recent years, in the fields of air-conditioning, air-conditioning, and automobile filters, there has been an increasing demand for higher performance and lower cost of filter media, and many studies have been made on filter media that achieve both dust removal performance and deodorization performance. . In general, in order to impart deodorizing performance, a method of forming a sheet using a particulate or fibrous adsorbent and an adhesive is often employed. For example, a mixture of a granular adsorbent and a granular adhesive is sprayed between substrates. However, an adsorption filter medium obtained by heat-bonding this has been developed (for example, Patent Document 1). However, such an adsorbent filter medium has a problem in that the adsorbent is dropped and the rigidity is lowered because the adhering strength is weak. In order to solve these problems, there is a method of increasing the mixing ratio of the adhesive. However, there is a problem that the deodorizing performance is reduced due to the coating on the surface of the adsorbent and the pressure loss is increased.

  Patent Document 2 describes an adsorbent sheet in which a needle punched nonwoven fabric layer and an adsorbing layer are adjacent to each other, and the fluff of the needle punched nonwoven fabric enters the adsorbing layer, and the adhesive strength is increased by an anchor effect. There was a demand for higher performance.

Japanese Patent Laid-Open No. 11-5058 JP 2007-301434 A

  It is an object of the present invention to provide a filter medium for a deodorizing filter that can sufficiently exhibit deodorizing performance while improving adhesiveness and rigidity and is excellent in pressure loss and dust retention.

As a result of intensive studies, the present inventors have found that the above problems can be solved by the following means, and have reached the present invention. The present invention is as follows.
(1) A filter medium composed of a laminated structure in which an adsorbent layer composed of an adsorbent and an adhesive is sandwiched between base material layers, wherein one layer of the base material layer is a resin-processed thermal bond nonwoven fabric, The other layer is a non-woven fabric composed of heat-bonding long fibers and an electret needle punch non-woven fabric laminated and integrated with a needle punch, and the adsorbing layer and the non-woven fabric composed of heat-bonding long fibers of the laminated sheet are adjacent to each other. Filter media for deodorizing filters laminated by heat fusion.
(2) The filter medium for a deodorizing filter according to (1), wherein the nonwoven fabric composed of the heat-sealing long fibers is a nonwoven fabric composed of composite heat-sealing long fibers having a core-sheath structure.

  The filter medium for a deodorizing filter according to the present invention can sufficiently exhibit deodorizing performance while improving adhesion and rigidity, and has an effect of being excellent in pressure loss and dust holding amount.

  The present invention is a filter medium composed of a laminated structure in which an adsorbent layer made of an adsorbent and an adhesive is sandwiched between base material layers, one layer of the base material layer is a resin-processed thermal bond nonwoven fabric, The other layer is composed of a laminated sheet obtained by laminating and integrating a non-woven fabric made of heat-sealing long fibers and electret needle punched non-woven fabric with a needle punch, and the adsorbing layer is adjacent to the non-woven fabric made of heat-bonding long fibers of the laminated sheet. The low melting point component of the heat-sealing long fibers constituting the nonwoven fabric composed of heat-bonding long fibers and the adhesive of the adsorption layer are firmly bonded by heat-sealing. It is a filter medium for deodorizing filters.

The nonwoven fabric composed of the heat-fusible long fibers used in one of the base material layers of the present invention comprises a composite long fiber having a core-sheath structure, and the core material is a high melting point polyethylene terephthalate or polybutylene terephthalate. It is preferable that the sheath material is polyethylene, polypropylene, low melting point polyester or the like having a low melting point.
If the heat-sealable long fiber is a core-sheath structure, even if the sheath part is reduced by heat-sealing, the core component remains so that the flatness of the non-woven fabric composed of the heat-sealable long fiber is not impaired, and the fiber Since it does not move in the thickness direction, high rigidity can be maintained as a filter medium.

  On the other hand, in the non-woven fabric composed of heat-bonding short fibers, the low melting point component of the heat-bonding short fibers and the adsorbent are bonded, but the short fibers are easy to move in the thickness direction, so the degree of freedom of the adsorbent is large. Sufficient rigidity cannot be obtained as a filter medium. On the other hand, as described above, if the nonwoven fabric is composed of heat-bonding long fibers, the fibers are difficult to move in the thickness direction, so the degree of freedom of the adsorbent adhered to the nonwoven fabric composed of heat-bonding long fibers is small, and the filter medium. High rigidity can be obtained.

5-40 g / m < ² > is preferable and the fabric weight of the nonwoven fabric consisting of the heat-fusion-type long fiber of this invention has more preferable 10-30 g / m < ² >. When the basis weight is less than 5 g / m ² , the area to be heat-sealed with the adsorption layer becomes small, and sufficient adhesive strength cannot be obtained. When the basis weight exceeds 40 g / m ² , not only the pressure loss increases with the increase in the number of fibers, but also the dust holding space between the fibers decreases, and the dust holding amount decreases.

  The fiber diameter of the heat-sealing long fibers constituting the nonwoven fabric composed of the heat-sealing long fibers of the present invention is preferably from 3 to 100 μm, more preferably from 5 to 80 μm, even more preferably from 10 to 60 μm. This is because, within this range, the adsorbing layer and the electret needle punched nonwoven fabric can be held together while maintaining flexibility, and the role of improving adhesive strength and increasing rigidity can be sufficiently achieved.

  In the filter medium for a deodorizing filter of the present invention, it is essential to use an electret needle punched nonwoven fabric. This is because there is an increasing demand for higher performance of filter media, and it is necessary to have both deodorization performance and fine dust removal performance.

  The electret needle punched nonwoven fabric used for one of the substrate layers of the present invention is preferably a frictionally charged filter medium composed of polyolefin fibers and polyester fibers. The material is not particularly limited, and polyethylene, polypropylene, or the like can be used for the polyolefin fiber, and polyethylene terephthalate, polytrimethylene terephthalate, aromatic polyester, or the like can be used for the polyester fiber.

  As for the fiber diameter of the polyolefin fiber and polyester fiber which comprise the electret needle punch nonwoven fabric of this invention, 3-30 micrometers is preferable. This is because the pressure loss is low within this range, and fine dust can be sufficiently removed. The mixing ratio of the polyolefin fiber and the polyester fiber is preferably 30:70 to 70:30 in mass ratio. This is because it can be effectively charged within such a range.

  The cross-sectional shape of the fibers constituting the electret needle punched nonwoven fabric of the present invention is not particularly limited, and may be any of a circular shape, a triangular shape, a rectangular shape, an irregular shape, and the like, but a fiber having a circular cross section is preferred. For example, when the fiber has a rectangular cross section, the contact area between the fibers increases, and the effective fiber surface area decreases. The fiber cross-sectional shape is not limited to a perfect circle as long as it does not have a straight portion, and may be an ellipse. Further, the fiber length is preferably 10 to 100 mm, and more preferably 30 to 80 mm, although it depends on the sheeting means of the frictionally charged filter medium. This is because, within such a range, a more uniform web can be produced in the carding of the fibers.

Basis weight of the electret needle punched nonwoven fabric of the present invention is preferably ^{10~100g / m 2, 10~50g / m} 2 is more preferable. If the basis weight is less than 10 g / m ² , fine dust cannot be sufficiently removed. On the other hand, if the basis weight exceeds 100 g / m ² , the pressure loss increases, which is not preferable in using the filter.

  A method of laminating a non-woven fabric composed of heat-bonding long fibers and an electret needle punch non-woven fabric is laminated by needle punch. When laminated and integrated with a needle punch, the constituent fibers of the electret needle punch nonwoven fabric are strongly entangled in the thickness direction with the nonwoven fabric composed of heat-bonding long fibers, and the penetrated fibers are bonded to the adsorption layer, resulting in secondary adhesive strength. It is because it can raise.

  A resin-processed thermal bond nonwoven fabric is used for the other side of the base material layer of the present invention. The thermal bond nonwoven fabric is a nonwoven fabric in which only the intersections between the fibers are bonded by the low melting point component of the fiber, but usually the fibers not having the low melting point component are mixed at a certain ratio in consideration of thermal shrinkage. Therefore, the adhesion at the intersection is partially weak, and the waist strength and tensile strength of the nonwoven fabric as a whole are often insufficient. Therefore, by applying resin processing to the thermal bond nonwoven fabric, it becomes possible to bond the intersections of all the fibers and increase the tensile strength as well as the waist strength.

The resin used for the resin processing of the thermal bond nonwoven fabric is not particularly limited, but a hard resin is preferable after processing, and acrylic resins such as acrylic ester resins and styrene-acrylic copolymer resins, polyester resins, and urethane resins are used. Acrylic resins and polyester resins are preferred because of their hardness and heat resistance. The resin amount used for the resin processing is preferably 1 to 10 g / m ² , more preferably ² to 5 g / m ² . If the amount of resin is small, sufficient rigidity cannot be obtained, and if the amount is large, air permeability is hindered. Further, an additional functional agent such as a flame retardant, an antibacterial and antifungal agent, and a pigment can be appropriately mixed with the resin component. In particular, when a pigment is mixed, the visibility at the time of dust loading is improved, and a guideline for the replacement time is known and preferable.

  Examples of the adsorbent used in the adsorption layer of the present invention include various adsorbents in powder form, granular form, crushed form, granulated form, and bead form, and an activated carbon system that can adsorb a wide variety of gases is preferable. For example, activated carbons such as coconut shell, wood, coal, and pitch are suitable. It is better that the number of so-called macropores introduced into the interior as seen by surface observation is large. When mixed powder is made from activated carbon and thermoplastic powder resin as an adhesive, even if the thermoplastic powder resin covers the activated carbon surface, it can be adsorbed by gas desorption from inside the pores during hot pressing. The pores can be opened. In addition, if the surface of the activated carbon is rough to some extent, the fluidity of the melted resin also deteriorates, and a decrease in adsorption performance can be suppressed.

  The particle size range of the adsorbent of the present invention is preferably 60 to 1000 μm, more preferably 100 to 900 μm as a value according to JIS standard sieve (JIS Z8801) in consideration of air permeability, adsorbent dropping, sheet processability and the like. . If the particle size range is less than 60 μm, the pressure loss becomes too large to obtain a certain high adsorption capacity, and the sheet packing density increases, so the pressure loss rises quickly when the dust is loaded, and the dust holding amount decreases. To do. When the particle size range exceeds 1000 μm, the sheet tends to fall off, the initial adsorption performance in one pass becomes extremely low, and when the air purification filter unit has a pleated shape or a wavy shape. Workability at the time of bending and corrugated processing deteriorates. In addition, said granular powder granular adsorbent can be obtained by carrying out predetermined particle size adjustment using a normal classifier.

10-450 g / m < ² > is preferable and, as for the weight of the adsorption agent contained in the filter medium of this invention, 50-350 g / m < ² > is more preferable. If it is this range, sufficient deodorizing performance can be obtained, suppressing the big raise of a pressure loss.

  The adsorbent of the present invention may be used after chemical treatment for the purpose of improving the adsorption performance of polar substances and aldehydes. Examples of chemicals used in gas chemical treatment include aldehyde gases, nitrogen compounds such as NOx, sulfur compounds such as SOx, and acidic polar substances such as acetic acid such as ethanolamine, polyethyleneimine, aniline, and P-anisidine. , Amine drugs such as sulfanilic acid, sodium hydroxide, potassium hydroxide, guanidine carbonate, guanidine phosphate, aminoguanidine sulfate, 5.5-dimethylhydantoin, benzoguanamine, 2.2-iminodiethanol, 2.2.2 -Nitrotriethanol, ethanolamine hydrochloride, 2-aminoethanol, 2.2-iminodiethanol hydrochloride, P-aminobenzoic acid, sodium sulfanilate, L-arginine, methylamine hydrochloride, semicarbazide hydrochloride, hydrazine, hydroquinone , Hydroxyla sulfate , Permanganate, potassium carbonate, potassium hydrogen carbonate, etc. are preferably used. For basic polar substances such as ammonia, methylamine, trimethylamine, pyridine, phosphoric acid, citric acid, malic acid, etc. Ascorbic acid, tartaric acid and the like are preferably used. The chemical treatment is performed by, for example, supporting or attaching a chemical to activated carbon. In addition to directly treating the activated carbon with chemicals, it is possible to impregnate the entire sheet or impregnate the entire sheet by a method such as an ordinary coating method in the vicinity of the sheet surface. At this time, a chemical aqueous solution in which a thickener such as sodium alginate or polyethylene oxide is mixed can be prepared, supported, and attached. This method is effective in supporting and attaching a chemical having low solubility in water and further suppressing the chemical from falling off.

  The adhesive used for the adsorption layer of the present invention is preferably a thermoplastic powder resin. If it is a powder resin, it can be uniformly dispersed in the fluff and the low melting point portion of a laminated sheet in which a nonwoven fabric composed of an adsorbent and a heat-sealing long fiber and an electret needle punched nonwoven fabric are laminated and integrated. Examples of the thermoplastic powder resin include polyolefin resin, polyamide resin, polyester resin, and ethylene-acrylic copolymer resin.

  As for the magnitude | size of the thermoplastic powder resin used for the adhesive agent of this invention, 1-40 micrometers is preferable at an average particle diameter, and 5-30 micrometers is more preferable. More preferably, it is 95% by weight or more in the range of 1 to 40 μm. When the average particle size is within this range, the thermoplastic resin can reduce the blocking of the surface pores of the granular adsorbent, while at the time of mixing with the adsorbent, to the granular adsorbent by van der Waals force or electrostatic force. This is because pre-adhesion is effectively performed and can be uniformly dispersed, and partial peeling between the adsorbent layer and the base material layer can be effectively prevented.

  The shape of the thermoplastic powder resin used for the adhesive of the present invention is not particularly limited, but examples thereof include a spherical shape and a crushed shape. Of course, two or more thermoplastic powder resins can be used in combination. Furthermore, even if a chemical-supported granular adsorbent or a chemical-supported non-woven fabric is used, if this prescription is used, the thermoplastic powder resin is temporarily bonded to the surface of the granular adsorbent from the time of mixing in the dry state. Therefore, even if the chemicals have different properties, they can be prevented from interfering with each other in the subsequent sheet forming step, so that a sufficient effect is exhibited.

  The thermoplastic powder resin contained in the filter medium of the present invention is preferably used in an amount of 1 to 40% by weight, more preferably 3 to 30% by weight, based on the adsorbent. This is because, within such a range, a filter material for a deodorizing filter excellent in adhesive strength with the base material layer, pressure loss, and deodorizing performance can be obtained.

  The filter medium of the present invention may contain components having ancillary functions such as antibacterial agents, antifungal agents, antiviral agents, and flame retardants. These components may be kneaded into fibers or non-woven fabrics, or may be added and supported by post-processing. For example, by including a flame retardant, FMVSS. It is possible to produce a filter medium for a deodorizing filter that meets the standards for retarding flame retardancy defined in 302 and UL flame retardant standards.

  In order to produce a sheet by finally hot pressing the filter medium of the present invention, a commonly used hot press method between rolls or a flat bed laminating method in which the upper and lower parts are sandwiched between flat heat belt conveyors can be used. The latter is more preferable for producing a more uniform thickness and adhesion. Moreover, by combining the laminated sheet for base material layers described in this patent and the characteristics of the above production method, it is possible to suppress excessive binding between the particulate adsorbents, and at the same time, practical use with the laminated sheet for base material layers. In addition, sufficient adhesive strength can be obtained.

  The manufacturing method of the filter medium for deodorizing filters of this invention is demonstrated. First, the adsorbent and the adhesive are weighed to a predetermined weight, put in a stirrer, and stirred at a rotational speed of 30 rpm for about 10 minutes. Next, the mixed powder is spread on the non-woven fabric side made of the heat-bonding long fibers of the base material layer made of the laminated sheet, and the base material layer made of the thermal bond non-woven fabric processed with the resin is laminated thereon to heat the mixed powder. Press processing. The sheet surface temperature during hot pressing is preferably 3 to 30 ° C., preferably 5 to 20 ° C. higher than the melting point of the thermoplastic resin.

  0.1-3.0 mm is preferable and, as for the thickness of the filter material for deodorizing filters of this invention, 0.5-2.0 mm is more preferable. If the thickness is less than 0.1 mm, the dust collection space is small, so that the pressure loss rises quickly when dust is loaded, and clogging occurs. On the other hand, if the thickness exceeds 3.0 mm, the thickness of the entire sheet is too thick, so that when the pleated unit is used, the structural resistance increases, and as a result, the pressure loss in the entire unit becomes too high, causing a practical problem.

The basis weight of the filter medium for the deodorizing filter of the present invention is preferably 30 to 500 g / m ² . If the basis weight is less than 30 g / m ² , the filter medium has low rigidity, so that the unit is deformed at the time of ventilation load, and the pressure loss increases. If it exceeds 500 g / m ² , the thickness of the sheet becomes so thick that the structural resistance in the case of a pleated unit becomes large, which is a practical problem.

  The thickness of the pleated filter unit using the filter medium of the present invention is preferably 10 to 400 mm. For in-vehicle applications such as built-in car air conditioners and home air purifiers, 40 to approximately 10 to 60 mm, a large filter unit that is often installed for building air conditioning applications, due to the normal internal space. About ~ 400 mm is preferable considering the storage space.

  Hereinafter, the present invention will be described in more detail with reference to examples. The characteristics shown in the examples were measured by the following methods.

(Pressure loss)
The filter medium was installed in the duct, the atmosphere was vented so that the air filtration speed was 31 cm / sec, the difference in static pressure upstream and downstream of the filter medium was read with a differential pressure gauge, and the pressure loss (Pa) was measured.

(0.3 μm particle collection efficiency)
The filter medium is installed in the duct, the atmosphere is vented so that the air filtration speed is 16 cm / sec, and the number concentration of 0.3 to 0.5 μm particles upstream and downstream of the filter medium is measured with a particle counter. The particle collection efficiency was calculated at
Particle collection efficiency (%) = [1− (downstream concentration / upstream concentration)] × 100

(Adhesive strength)
Measure the average peel strength between the substrate layers on both sides. The size of the test piece was 50 mm wide, 200 mm long, and the tensile strength was 100 mm / min.

(rigidity)
Based on JIS L-1096 A method (Gurley method), the bending resistance in the MD direction was measured.

(Toluene removal efficiency)
The filter medium is placed in the duct, the atmosphere is vented so that the air filtration speed is 16 cm / sec, and toluene gas is injected so that the upstream concentration of the filter medium is 80 ppm. The upstream / downstream concentration after 1 minute from the start of measurement was measured with a hydrocarbon meter, and the initial removal efficiency of toluene gas was calculated by the following equation.
Toluene removal efficiency (%) = [1− (downstream concentration / upstream concentration)] × 100

(Dust dust holding amount)
A filter is installed in the duct, and the atmosphere is vented so that the air filtration speed is 31 cm / second. A2 (Fine) dust defined in ISO standard 10103-1 (2012) is 1.0 g / The load was applied at a concentration of m ³ until the initial pressure loss increased by 150 Pa, and the amount of collected dust was defined as the amount of retained dust (g / m ² ).

[Example 1]
Polypropylene fiber (fineness: 2.2 dtex, fiber length: 51 mm) and polyester fiber (fineness: 1.7 dtex, fiber length: 44 mm) are mixed in a weight ratio of 1: 1 and carded to form a mixed fiber web having a basis weight of 25 g / m ^2. After production, 3 MPa high-pressure water was continuously sprayed to entangle and dry to produce a mixed fiber sheet. A nonwoven fabric composed of a core-sheath type composite heat-sealing long fiber (fiber diameter 30 μm) composed of polyester (core) / polyethylene (sheath) having a basis weight of 12 g / m ² is laminated and integrated into this mixed fiber sheet by needle punching. Then, triboelectric charging was performed to obtain a base material layer made of an electret laminated sheet.
Also, polyester fiber (fineness 17 dtex, fiber length 51 mm), low melting point polyester fiber (fineness 4.4 dtex, fiber length 51 mm) and low melting point polyester fiber (fineness 22 dtex, fiber length 51 mm) in a weight ratio of 2: 3: 5. The mixture was carded and carded and thermally fused by a thermal bond method to obtain a thermal bond nonwoven fabric having a basis weight of 65 g / m ² . Further, the thermal bond nonwoven fabric was immersed in an aqueous polyester resin solution and then dried to obtain a base material layer processed with ² g / m ² of polyester resin.
Next, to the non-woven fabric side comprising the heat-bonding long fibers of the electret laminated sheet base material layer, coconut husk activated carbon having an average particle size of 550 μm and an ethylene acrylic acid copolymer (particle size 10 μm, melting point 109 ° C.) as a thermoplastic powder resin A mixed powder having a weight ratio of 1: 0.1 was sprayed so as to have a basis weight of 220 g / m ^2, and a low melting point polyester hot melt sheet (12 g / m ² , melting point 105 ° C.) and a thermal bond group as an adhesive layer from above. The material layers were sequentially stacked and formed into a sheet by heat treatment at 140 ° C. for 30 seconds to obtain a filter medium for a deodorizing filter.
Table 1 shows the sheet characteristics of the obtained filter medium.

[Example 2]
Polypropylene fiber (fineness: 2.2 dtex, fiber length: 51 mm) and polyester fiber (fineness: 1.7 dtex, fiber length: 44 mm) are mixed in a weight ratio of 1: 1 and carded to form a mixed fiber web having a basis weight of 25 g / m ^2. After production, 3 MPa high-pressure water was continuously sprayed to entangle and dry to produce a mixed fiber sheet. A nonwoven fabric composed of a core-sheath type composite heat-sealing long fiber (fiber diameter 30 μm) composed of polyester (core) / polyethylene (sheath) having a basis weight of 12 g / m ² is laminated and integrated into this mixed fiber sheet by needle punching. Then, triboelectric charging was performed to obtain a base material layer made of an electret laminated sheet.
Also, polyester fiber (fineness 17 dtex, fiber length 51 mm), low melting point polyester fiber (fineness 4.4 dtex, fiber length 51 mm) and low melting point polyester fiber (fineness 22 dtex, fiber length 51 mm) in a weight ratio of 2: 3: 5. The mixture was carded and carded and thermally fused by a thermal bond method to obtain a thermal bond nonwoven fabric having a basis weight of 65 g / m ² . Further, the thermal bond nonwoven fabric was immersed in an aqueous polyester resin solution and then dried to obtain a base material layer processed with ² g / m ² of polyester resin.
Next, to the non-woven fabric side comprising the heat-bonding long fibers of the electret laminated sheet base material layer, coconut husk activated carbon having an average particle size of 550 μm and an ethylene acrylic acid copolymer (particle size 10 μm, melting point 109 ° C.) as a thermoplastic powder resin A mixed powder having a weight ratio of 1: 0.05 was sprayed so as to have a basis weight of 210 g / m ^2, and a low-melting polyester hot melt sheet (12 g / m ² , melting point 105 ° C.) and a thermal bond group as an adhesive layer from above. The material layers were sequentially stacked and formed into a sheet by heat treatment at 140 ° C. for 30 seconds to obtain a filter medium for a deodorizing filter.
Table 1 shows the sheet characteristics of the obtained filter medium.

[Example 3]
Polypropylene fiber (fineness: 2.2 dtex, fiber length: 51 mm) and polyester fiber (fineness: 1.7 dtex, fiber length: 44 mm) are mixed in a weight ratio of 1: 1 and carded to form a mixed fiber web having a basis weight of 25 g / m ^2. After production, 3 MPa high-pressure water was continuously sprayed to entangle and dry to produce a mixed fiber sheet. A nonwoven fabric composed of a core-sheath type composite heat-sealing long fiber (fiber diameter 30 μm) composed of polyester (core) / polyethylene (sheath) having a basis weight of 12 g / m ² is laminated and integrated into this mixed fiber sheet by needle punching. Then, triboelectric charging was performed to obtain a base material layer made of an electret laminated sheet.
Also, polyester fiber (fineness 17 dtex, fiber length 51 mm), low melting polyester fiber (fineness 4.4 dtex, fiber length 51 mm) and low melting polyester fiber (fineness 22 dtex, fiber length 51 mm) in a weight ratio of 2: 3: 5. The mixture was carded and carded and thermally fused by a thermal bond method to obtain a thermal bond nonwoven fabric having a basis weight of 65 g / m ² . After further immersing the thermal bond nonwoven fabric in the polyester resin and green pigment aqueous green pigment dried 2 g / m ² of polyester resin and 1 g / m ² was obtained by the base layer processing.
Next, to the non-woven fabric side comprising the heat-bonding long fibers of the electret laminated sheet base material layer, coconut husk activated carbon having an average particle size of 550 μm and an ethylene acrylic acid copolymer (particle size 10 μm, melting point 109 ° C.) as a thermoplastic powder resin A mixed powder having a weight ratio of 1: 0.05 was sprayed so as to have a basis weight of 210 g / m ^2, and a low-melting polyester hot melt sheet (12 g / m ² , melting point 105 ° C.) and a thermal bond group as an adhesive layer from above. The material layers were sequentially stacked and formed into a sheet by heat treatment at 140 ° C. for 30 seconds to obtain a filter medium for a deodorizing filter.
Table 1 shows the sheet characteristics of the obtained filter medium.

[Example 4]
Polypropylene fiber (fineness: 2.2 dtex, fiber length: 51 mm) and polyester fiber (fineness: 1.7 dtex, fiber length: 44 mm) are mixed in a weight ratio of 1: 1 and carded to form a mixed fiber web having a basis weight of 25 g / m ^2. After production, 3 MPa high-pressure water was continuously sprayed to entangle and dry to produce a mixed fiber sheet. A nonwoven fabric composed of a core-sheath type composite heat-sealing long fiber (fiber diameter 30 μm) composed of polyester (core) / polyethylene (sheath) having a basis weight of 12 g / m ² is laminated and integrated into this mixed fiber sheet by needle punching. Then, triboelectric charging was performed to obtain a base material layer made of an electret laminated sheet.
Also, polyester fiber (fineness 17 dtex, fiber length 51 mm), low melting point polyester fiber (fineness 4.4 dtex, fiber length 51 mm) and low melting point polyester fiber (fineness 22 dtex, fiber length 51 mm) in a weight ratio of 2: 3: 5. The mixture was carded and carded and thermally fused by a thermal bond method to obtain a thermal bond nonwoven fabric having a basis weight of 65 g / m ² . Further, the thermal bond nonwoven fabric was immersed in an aqueous polyester resin solution and then dried to obtain a base material layer processed with ² g / m ² of polyester resin.
Next, to the non-woven fabric side comprising the heat-bonding long fibers of the electret laminated sheet base material layer, coconut husk activated carbon having an average particle size of 550 μm and an ethylene acrylic acid copolymer (particle size 10 μm, melting point 109 ° C.) as a thermoplastic powder resin A mixed powder with a weight ratio of 1: 0.1 is sprayed so as to have a basis weight of 220 g / m ^2. Further, a thermal bond base material layer is superimposed from above, and a sheet is formed by heating at 140 ° C. for 30 seconds to deodorize. A filter medium for a filter was obtained.
Table 1 shows the sheet characteristics of the obtained filter medium.

[Comparative Example 1]
In Example 1, except that resin processing was not performed on the base material layer made of the thermal bond nonwoven fabric, a sheet was formed in the same manner as in Example 1 to obtain a filter medium for a deodorizing filter.
Table 1 shows the sheet characteristics of the obtained filter medium.

[Comparative Example 2]
Polypropylene fiber (fineness: 2.2 dtex, fiber length: 51 mm) and polyester fiber (fineness: 1.7 dtex, fiber length: 44 mm) are mixed in a weight ratio of 1: 1 and carded to form a mixed fiber web having a basis weight of 25 g / m ^2. After production, 3 MPa high-pressure water was continuously sprayed to entangle and dry to produce a mixed fiber sheet. The mixed fiber sheet was triboelectrically charged with a needle punch to obtain a base material layer made of an electret sheet.
Also, polyester fiber (fineness 17 dtex, fiber length 51 mm), low melting point polyester fiber (fineness 4.4 dtex, fiber length 51 mm) and low melting point polyester fiber (fineness 22 dtex, fiber length 51 mm) in a weight ratio of 2: 3: 5. The mixture was carded and carded and thermally fused by a thermal bond method to obtain a thermal bond nonwoven fabric having a basis weight of 65 g / m ² . Further, the thermal bond nonwoven fabric was immersed in an aqueous polyester resin solution and then dried to obtain a base material layer processed with ² g / m ² of polyester resin.
Next, coconut husk activated carbon having an average particle diameter of 550 μm and a mixed powder having an ethylene acrylic acid copolymer (particle diameter of 10 μm, melting point of 109 ° C.) in a weight ratio of 1: 0.1 as a thermoplastic powder resin are applied to the electret sheet base material layer. It is sprayed to 220 g / m ^2, and a low-melting polyester hot melt sheet (12 g / m ² , melting point 105 ° C.) and a thermal bond base material layer are sequentially laminated as an adhesive layer from the top, and 140 ° C. for 30 seconds. A sheet was formed by heat treatment to obtain a filter medium for a deodorizing filter.
Table 1 shows the sheet characteristics of the obtained filter medium.

[Comparative Example 3]
Polypropylene fiber (fineness: 2.2 dtex, fiber length: 51 mm) and polyester fiber (fineness: 1.7 dtex, fiber length: 44 mm) are mixed in a weight ratio of 1: 1 and carded to form a mixed fiber web having a basis weight of 25 g / m ^2. After production, 3 MPa high-pressure water was continuously sprayed to entangle and dry to produce a mixed fiber sheet. A nonwoven fabric made of low-melting-point polyester short fibers with a basis weight of 12 g / m ² (fineness: 4.4 dtex, fiber length: 51 mm) is laminated and integrated with this punched sheet by needle punching, and further triboelectrically charged to form an electret laminated sheet. A substrate layer was obtained.
Also, polyester fiber (fineness 17 dtex, fiber length 51 mm), low melting point polyester fiber (fineness 4.4 dtex, fiber length 51 mm) and low melting point polyester fiber (fineness 22 dtex, fiber length 51 mm) in a weight ratio of 2: 3: 5. The mixture was carded and carded and thermally fused by a thermal bond method to obtain a thermal bond nonwoven fabric having a basis weight of 65 g / m ² . Further, the thermal bond nonwoven fabric was immersed in an aqueous polyester resin solution and then dried to obtain a base material layer processed with ² g / m ² of polyester resin.
Next, the weight of an ethylene acrylic acid copolymer (particle size 10 μm, melting point 109 ° C.) as a coconut husk activated carbon having an average particle size of 550 μm and a thermoplastic powder resin is applied to the nonwoven fabric side comprising the low melting point polyester short fibers of the electret laminated sheet base material layer. A mixed powder having a ratio of 1: 0.1 was sprayed so as to have a basis weight of 220 g / m ^2, and a low-melting polyester hot melt sheet (12 g / m ² , melting point 105 ° C.) and a thermal bond base material as an adhesive layer from above. The layers were layered in order and formed into a sheet by heat treatment at 140 ° C. for 30 seconds to obtain a filter medium for a deodorizing filter.
Table 1 shows the sheet characteristics of the obtained filter medium.

[Comparative Example 4]
Polypropylene fiber (fineness: 2.2 dtex, fiber length: 51 mm) and polyester fiber (fineness: 1.7 dtex, fiber length: 44 mm) are mixed in a weight ratio of 1: 1 and carded to form a mixed fiber web having a basis weight of 25 g / m ^2. After production, 3 MPa high-pressure water was continuously sprayed to entangle and dry to produce a mixed fiber sheet. A nonwoven fabric composed of a core-sheath type composite heat-sealing long fiber (fiber diameter 30 μm) composed of polyester (core) / polyethylene (sheath) having a basis weight of 12 g / m ² is laminated and integrated into this mixed fiber sheet by needle punching. Then, triboelectric charging was performed to obtain a base material layer made of an electret laminated sheet.
Also, polyester fiber (fineness 17 dtex, fiber length 51 mm), low melting point polyester fiber (fineness 4.4 dtex, fiber length 51 mm) and low melting point polyester fiber (fineness 22 dtex, fiber length 51 mm) in a weight ratio of 2: 3: 5. A base material layer made of a thermal bond nonwoven fabric having a basis weight of 65 g / m ² was obtained by blending and carding and heat-sealing by a thermal bond method.
Next, to the non-woven fabric side comprising the heat-bonding long fibers of the electret laminated sheet base material layer, coconut husk activated carbon having an average particle size of 550 μm and an ethylene acrylic acid copolymer (particle size 10 μm, melting point 109 ° C.) as a thermoplastic powder resin A mixed powder having a weight ratio of 1: 0.2 was sprayed so as to have a basis weight of 240 g / m ^2, and a hot-melt sheet of low-melting polyester (12 g / m ² , melting point 105 ° C.) and a thermal bond group as an adhesive layer from above. The material layers were sequentially stacked and formed into a sheet by heat treatment at 140 ° C. for 30 seconds to obtain a filter medium for a deodorizing filter.
Table 1 shows the sheet characteristics of the obtained filter medium.

  The filter media obtained in Examples 1 to 4 had high rigidity, low pressure loss, high dust holding capacity, and excellent deodorization performance. On the other hand, the filter media obtained in Comparative Examples 1 to 3 have low rigidity, and the filter media obtained in Comparative Example 4 are inferior in deodorizing performance and are not suitable as filter media for deodorizing filters.

  The filter medium for a deodorizing filter obtained by the present invention has high rigidity and excellent pressure loss and dust holding capacity, and is a filter medium that can be used for a long time, and greatly contributes to the industry.

Claims (2)

  A filter medium composed of a laminated structure in which an adsorbent layer composed of an adsorbent and an adhesive is sandwiched between base material layers, wherein one layer of the base material layer is a resin-processed thermal bond nonwoven fabric, and the other layer of the base material layer is It consists of a laminated sheet in which a nonwoven fabric composed of heat-bonding long fibers and electret needle punched nonwoven fabric are laminated and integrated with a needle punch, and the adsorbing layer and the nonwoven fabric composed of heat-bonding long fibers of the laminated sheet are adjacent to each other and heat-sealed. Filter media for deodorizing filters that are laminated with each other.   The filter medium for a deodorizing filter according to claim 1, wherein the nonwoven fabric composed of heat-sealing long fibers is a nonwoven fabric composed of composite heat-sealing long fibers having a core-sheath structure.