JP2019171250A - Air filter medium and air filter - Google Patents

Abstract

To achieve an air filter medium that can provide an air filter which has an excellent aeration property and pleat processing performance and has excellent dust holding performance, in which a pleat shape of the air filter is hardly deformed when the filter is used under high wind speed.SOLUTION: A deodorant-enclosing air filter medium has a deodorant sandwiched between an air-permeable base material A and an air-permeable base material B and has the deodorant enclosed thereinto with granular thermoplastic adhesives, in which the thermoplastic adhesives are scattered about while keeping a granular shape, where in the air-permeable base material A, weight per unit area is 40-100 g/mand a thickness is 0.3-1.4 mm, wind-pressure tolerability in MD of a non-woven is equal to 6.5 g or more and is 4.5 g or more in CD thereof. The air filter medium is constituted of the non-woven.SELECTED DRAWING: None

Description

  The present invention relates to an air filter medium and an air filter. More specifically, the present invention relates to an air filter medium and an air filter that can be used as an air purification filter in general rooms such as buildings and houses, automobiles, airplanes, and the like.

  In recent years, from the impact on the health of deserts in East Asia, dust (yellow sand) from dry areas, pollen of pollen such as PM2.5, cedar, cypress, and infections caused by viruses such as influenza, There are many living environments in which indoor air is purified, temperature-controlled, and humidity-controlled using air purifiers and air conditioners instead of ventilation of indoor air with windows open. In particular, there is a strong market demand for the function of improving the comfort of spaces such as homes, workplaces, and automobiles, and the use of air purification means is progressing. As familiar air purifying means, an air filter mounted on an air purifier, an air conditioner or the like is known.

  An air filter medium that is a material of an air filter is required to have a pressure loss as small as possible and to have a dust collection efficiency. In addition, a nonwoven fabric is generally used as the air filter medium, but the nonwoven fabric is pleated to increase the contact area with air and reduce airflow resistance, and is used as an air filter. Therefore, air filter media and air filters can easily and reliably pleat the air filter media, and maintain the pleat shape when the air filter is used at high wind speeds. It is necessary to have a durable structure, a dust holding characteristic that can hold more dust at a certain pressure loss level, and the like.

  Conventionally, as a method for producing a filter medium having deodorizing performance, a method of forming a filter medium by sandwiching a deodorant and a thermoplastic adhesive between breathable nonwoven fabrics is generally known. The deodorant-enclosed filter medium obtained by this method can enclose a large amount of deodorant in the filter medium, so that it is possible to produce a filter medium having high deodorizing performance, while the filter having an increased amount of deodorant Then, the pressure loss sometimes increased (for example, see Patent Documents 1 and 2).

  As an air filter medium having pleat workability or pleated structure durability, an air filter medium having improved mechanical strength represented by rigidity has been proposed. As the stiffness index, “flexibility” is used. The bending resistance is defined in JIS L 1913 “General nonwoven fabric testing method”, JIS L 1096 “Textile and knitted fabric testing method”, etc., and is constant as an air filter medium having pleatability and pleated structure durability. An air filter medium composed of a non-woven fabric satisfying a bending resistance greater than or equal to the value is disclosed. As a method for measuring the bending resistance, a cantilever method, a Gurley method, a handle ohm method, a slide method, or the like is used (for example, see Patent Documents 3 to 7). However, even if it is an air filter medium composed of non-woven fabric with a bending resistance specified by JIS standards of a certain value or more, when it is used at high wind speeds, the pleat shape of the air filter cannot be maintained. In some cases, the retention capacity was reduced.

  Accordingly, an air filter medium is provided that has an excellent air permeability, an excellent pleatability, a pleated structure durability when used at high wind speeds, and an air filter having good dust retention characteristics. It was sought to do.

JP, 2006-171875, A JP 2014-100654 A1 JP 05-031310 A JP 2006-130369 A JP-A-11-293555 JP 2017-056386 A JP2015-140495A

  In the present invention, it is possible to provide an air filter that has good air permeability, excellent pleat workability, and the pleat shape of the air filter is not easily deformed when used at high wind speeds and has good dust holding performance. An object is to obtain an air filter medium that can be used.

As means for solving the above problems, the present invention comprises the following (I) to (II).
(I) A deodorant-enclosed air filter medium in which a deodorizer is sandwiched between a breathable substrate A and a breathable substrate B and encapsulated with a granular thermoplastic adhesive, wherein the thermoplastic adhesive is granular. Scattered in a maintained state, the breathable substrate A has a basis weight of 40 to 100 g / m ² , a thickness of 0.3 to 1.4 mm, and the wind pressure resistance defined below (unit: g) ] Is 6.5 g or more in MD of the non-woven fabric, and 4.5 g or more in the CD, and is constituted by the non-woven fabric.

  Wind pressure resistance: Two pedestals (width 57 mm x depth over 40 mm x height 155 mm, made of polystyrene) are fixed at a distance of 52 mm, and a non-woven fabric having a long side of 140 mm and a short side of 40 mm is placed between the top plates of the two pedestals. The long side direction and the width direction of the pedestal are passed in parallel, the container is suspended from the center line in the long side direction of the nonwoven fabric, the weight is gradually added to the container, and the "mass of the container at the time the container falls + Mass of weight is defined as “wind pressure resistance”.

(II) An air filter using the air filter medium described in (I) above.

  The air filter medium of the present invention has good air permeability and pleatability, and by using the air filter medium of the present invention, the pleat shape of the air filter is less likely to be deformed when used at high wind speeds. An air filter having dust holding performance can be provided.

It is a figure which shows the measuring method of wind pressure tolerance. It is a figure which shows the measuring method of wind pressure tolerance.

  Hereinafter, the air filter medium of the present invention will be described in detail. Note that the present invention is not limited to these embodiments.

The air filter medium of the present invention is a deodorant-enclosed air filter medium formed by sandwiching a deodorizer between a breathable substrate A and a breathable substrate B and encapsulating with a granular thermoplastic adhesive. While the adhesive is scattered in a granular state, the breathable substrate A has a basis weight of 40 to 100 g / m ² , a thickness of 0.3 to 1.4 mm, and wind pressure resistance [unit: g ] Is 6.5 g or more in MD of nonwoven fabric and 4.5 g or more in CD, and is an air filter medium characterized by being composed of a nonwoven fabric.

  Below, the said air permeable base material A, the air permeable base material B, a deodorizing agent, and a granular thermoplastic adhesive are demonstrated one by one.

[Breathable substrate A]
Nonwoven fabric (nonwoven fabric a) used for the breathable substrate A according to the present invention is composed of polyamide fiber, polyester fiber, polyalkylene paraoxybenzoate fiber, polyurethane fiber, polyvinyl alcohol fiber, polyvinylidene chloride fiber, poly Synthetic fibers such as vinyl chloride fibers, polyacrylonitrile fibers, polyolefin fibers, phenol fibers; inorganic fibers such as glass fibers, metal fibers, alumina fibers, carbon fibers, activated carbon fibers: wood pulp, bamboo pulp, hemp pulp , Kenaf pulp, straw pulp, bagasse pulp, cotton linter pulp, natural fibers such as cotton, wool and silk, recycled cellulose fibers such as recycled paper pulp and rayon; proteins such as collagen, polysaccharides such as alginic acid, chitin, chitosan and starch Single or group of recycled fibers made from Together it can be used. These fibers may be provided with functions such as flame retardancy and hydrophilicity.

  There is no particular limitation on the production method of the nonwoven fabric a, and the web obtained by a dry method, a wet papermaking method, a melt blown method, a spunbond method, a flash spinning method, an airlaid method, etc., according to the purpose and application, hydroentangled method, Manufacture by appropriately combining physical methods such as needle punch method and stitch bond method, heat bonding method such as thermal bond method, and adhesive method such as chemical bond method and resin bond method to develop strength Can do.

  If necessary, the non-woven fabric a can be used to remove coarse particles, antibacterial, antifungal, antiviral, antiallergen, insecticidal, insecticidal, deodorant, fragrance, temperature sensitive, heat retaining, heat storage, heat storage, heat generation, heat absorption, water resistance , Water resistance, water repellency, hydrophobicity, hydrophilicity, dehumidification, humidity control, moisture absorption, oil repellency, lipophilicity, oil absorption, and various functions such as transpiration or sustained release of water and volatile chemicals May be used.

  When antibacterial performance is added to the nonwoven fabric a by post-processing, the method is not particularly limited. For example, in the case of attachment, poly (meth) acrylates, polyvinyl acetate, polyvinyl chloride, A water-dispersible binder such as styrene-acrylic resin and styrene-butadiene latex and a water-soluble binder such as polyvinyl alcohol may be appropriately selected and used.

The basis weight of the air-permeable base material A is 40 to 100 g / m ² , and more preferably 50 to 80 g / m ² . When the basis weight is less than 40 g / m ² , the air filter may be deformed when the pleated air filter is used at a high wind speed. When the basis weight is more than 100 g / m ² , pleatability There may be a decrease in pressure and an increase in pressure loss (pressure loss).

  The thickness of the breathable substrate A is 0.3 to 1.4 mm, and more preferably 0.4 to 1.0 mm, in order to obtain good pleat processability and pleated structure durability. If the nonwoven fabric is thinner than 0.3 mm, the air filter may be deformed when the pleated air filter is used at high wind speeds, while if it is thicker than 1.4 mm, the pleated It becomes difficult to apply, and there arises a problem that the heights of the pleats are not uniform and a problem that the filter medium meanders.

  “Wind pressure resistance” will be described with reference to FIGS. 1 and 2. FIG. 1 is a view showing a method for measuring wind pressure resistance, FIG. 1 (A) is a view seen from the side, and FIG. 1 (B) is a view seen from above. In the present invention, the two pedestals 2 are fixed so that the distance L2 is 52 mm, and the nonwoven fabric 1 having a long side of 140 mm and a short side of 40 mm is placed between the top plates of the two pedestals 2 and the length of the nonwoven fabric 1 is increased. The side 3 and the width direction of the pedestal 2 are passed in parallel, the container 3 is suspended from the center line in the long side direction of the nonwoven fabric 1, and the weight 4 is gradually added to the container 3 as shown in FIG. The “mass of the container 3 + the mass of the weight 4” when the container 3 is dropped is defined as “wind pressure resistance”. As the base 2, a polystyrene box having a width L1 of 57 mm, a depth of more than 40 mm, and a height H of 155 mm was used. The depth of the base 2 may be any length as long as the width of the nonwoven fabric 1 exceeds 40 mm. The container 3 was hung from the center line in the long side direction of the nonwoven fabric 1 using a thread passed through a resin tube (made of straw, polypropylene) 5 having an outer diameter of 4 mm. For the weight 4, a weight for an upper pan balance was used.

  The wind pressure resistance of MD is the wind pressure resistance of the nonwoven fabric 1 whose long side (140 mm) is MD and the short side (40 mm) is CD, and the wind pressure resistance of CD is the long side (140 mm) is CD and the short side ( 40 mm) is the wind pressure resistance of the nonwoven fabric 1 which is MD. In addition, the nonwoven fabric 1 is conveyed by conveyance support bodies, such as a wire and a felt, at the time of manufacture. The non-woven fabric 1 is arranged so that the surface that does not contact the carrier for support is the “front surface”, the surface that is in contact with the carrier for support is the “back surface”, and the “front surface” is on the top. The nonwoven fabric 1 is arranged so that the “front surface average value” and the “back surface”, which are average values of the measured values of the wind pressure resistance of 5 or more nonwoven fabrics 1, are on the top. The “back surface average value”, which is the average value of the measured wind pressure resistance, was calculated, and the average value of the “front surface average value” and the “back surface average value” was defined as “wind pressure resistance”.

  In the present invention, the wind pressure resistance [unit: g] of the nonwoven fabric is 6.5 g or more in MD of the nonwoven fabric and 4.5 g or more in CD. More preferably, it is 7.0 g or more in the MD of the nonwoven fabric and 4.8 g or more in the CD. When the wind pressure resistance of MD is 6.5 g or more and the wind pressure resistance of CD is 4.5 g or more, the air filter is not easily deformed when the pleated air filter is used at a high wind speed.

  As a method of adjusting the wind pressure resistance of the breathable substrate A, a method of adjusting the basis weight and thickness of the nonwoven fabric a, a method of changing the material of the fibers constituting the nonwoven fabric a, the fiber diameter of the fibers constituting the nonwoven fabric a, and / Or a method of adjusting the fiber length, a method of changing the composition of the fibers constituting the nonwoven fabric a, manufacturing conditions for producing the nonwoven fabric a (heating temperature, pressure, stretching degree, melting or softening temperature of the adhesive or binder fiber, And the like, and the like, and the like can be selected as appropriate from these methods.

[Breathable base material B]
The nonwoven fabric (nonwoven fabric b) used for the air-permeable base material B according to the present invention is preferably made of an electret (electric stone) that retains electric polarization semipermanently and exerts an electric force on the outside, and is particularly limited. Although it is not a thing, since it has the characteristics which have high dust collection performance and air permeability, it is more preferable to consist of meltblown electrets.

  The meltblown electret is generally a meltblown filter mainly composed of polypropylene or a polypropylene-based copolymer resin and electretized by the thermal electret method or the electroelectret method. For the purpose of improving heat resistance, etc. An appropriate amount of a fatty acid metal salt such as aluminum acid may be added.

Although the air permeable base material B used for this invention is not specifically limited, 6-40 g / m < ² > of fabric weight is preferable, More preferably, it is 10-30 g / m < ² >. If the basis weight of the air-permeable base material B is less than 6 g / m ² , the physical strength is inferior, so that tearing may occur in processing steps such as pleating, and if it exceeds 40 g / m ² , the filter medium may be clogged. May be more likely to occur.

  In addition, when using an electret made of melt blown, for the purpose of supplementing the physical strength of the breathable base material B and preventing the adsorbent to be encapsulated, the breathable manufactured by the spunbond method or the like, if necessary. What laminated | stacked a certain nonwoven fabric with the melt blown electret may be used as the air permeable base material B. FIG. As a method of laminating two non-woven fabrics, a part or whole is bonded by a pin sonic method or a hot melt powder method such as a hot melt spray method or a so-called sinter method. The method of integrating is illustrated.

[Deodorizer]
The deodorizing agent in the present invention is a general term for agents mainly used for the purpose of removing malodor, and specifically, activated carbon, impregnated activated carbon, natural and synthetic zeolite, sepiolite, activated alumina, activated clay, ion exchange resin, iron Adsorbing deodorizers such as ascorbic acid and iron phthalocyanine derivatives, low-temperature oxidation catalysts such as manganese-based oxides and perovskite-type catalysts, photocatalysts such as titanium oxide and zinc oxide, catechins, tannins, flavonoids that are compounds contained in plant extract components, Iron-based compounds such as iron oxide, zinc oxide, magnesium oxide, silica, silica-zinc oxide composite, silica-alumina-zinc oxide composite, manganese dioxide, composite phyllosilicate, cyclodextrin, ascorbic acid and divalent iron salt Examples thereof include a mixture, a mixture of vitamin B group and phosphate, and the like. Although the shape of these deodorizers is not particularly limited, particulate ones are preferable, and those having a specific surface area of 50 to 2000 m ² / g can be appropriately selected and used according to the deodorization performance requirements.

[Granular thermoplastic adhesive]
The granular thermoplastic adhesive used in the present invention is mainly composed of a thermoplastic resin. As the thermoplastic resin, an ethylene vinyl acetate copolymer or a modified product thereof, an ethylene acrylate copolymer, an ionomer, a polyamide, and a nylon are used. , Polyester, polyethylene, polypropylene, polyurethane resins and the like.

  The softening point or melting point of the granular thermoplastic adhesive is not particularly limited, and the post-processing conditions after producing the air filter medium, such as folding, the ambient temperature, the air filter constituent material other than the granular thermoplastic adhesive It may be selected as appropriate in consideration of the heat resistance of the material.

  The granular thermoplastic adhesive in the present invention is not particularly limited with respect to the particle size, but 80% by weight or more of the total particles is preferably 20 to 150 mesh, more preferably 32 to 100 mesh. . If there are many particles of less than 20 mesh, irregularities may occur on the air filter medium obtained, in particular on the breathable substrate B side, and the filter medium may be damaged in subsequent processes such as pleating. If the amount is large, problems such as separation from the eyes of the nonwoven fabric may occur.

  In the present invention, `` the thermoplastic adhesive is scattered in a state of maintaining granularity '' means that the granular thermoplastic adhesive does not completely melt to the center of the particle, or the fluidity after melting is low, etc. The thermoplastic adhesive does not spread completely even after melting, and is in a state of being cooled and solidified while maintaining granularity. The determination method of the state that “the thermoplastic adhesive is scattered in a granular state” is to separate the filter medium after the encapsulation process and visually observe the granular thermoplastic adhesive present in the deodorizing material layer with the naked eye or a loupe. It can be determined by doing. Note that the determination method of the present invention is not limited to a specific method.

[Air filter media]
Next, a method for producing the air filter medium of the present invention will be described.

  The process for producing the air filter medium in the present invention is not particularly limited. Generally, a deodorant and a granular thermoplastic adhesive are distributed on the air-permeable base material A on the air inflow side, and the air on the air outflow side is ventilated. The adhesive base material B is overlapped, and the adhesiveness of the thermoplastic adhesive is expressed by heating and is integrally manufactured.

  When a deodorant and a granular thermoplastic adhesive are spread on one nonwoven fabric, they may be spread separately, but if there is no particular influence on the deodorizer, a premixed one may be spread. preferable. Examples of the spraying method include spraying by free fall from the lower part of the hopper, spraying by air blown in the air, spray coating with water dispersion, die coating, and the like.

  Heating in the air filter medium manufacturing process is not particularly limited, but is basically roughly divided into two systems. That is, one is a system in which a granular thermoplastic adhesive, preferably a deodorizing agent and a granular thermoplastic adhesive are spread on one nonwoven fabric and then heated. The other is a method in which a deodorant and a granular thermoplastic adhesive are spread on one nonwoven fabric, and the other nonwoven fabric is overlaid and then heated. In order to produce the air filter medium of the present invention, either heating method may be used as desired, or both heating methods may be used in combination.

  As a method of heating after spraying a granular thermoplastic adhesive, preferably a deodorizing agent and a granular thermoplastic adhesive on one breathable substrate, there is a method of heating from the side where the granular thermoplastic adhesive is distributed, Since heating by contact-type heat conduction is difficult, it is preferable to employ a non-contact type heating means such as hot air, and particularly, a means using radiant heat such as an infrared heater or a gas burner heater is particularly preferable.

  In the non-contact type heating means, the side to which the radiant heat or hot air is applied is not particularly limited, but it is preferable to heat from the side on which the granular thermoplastic adhesive is applied.

  A heating method in which at least one is sandwiched between two heated rolls as a method of heating after spreading a deodorant and a granular thermoplastic adhesive on one breathable substrate and overlaying the other breathable substrate. And a contact heating system such as a heating system sandwiched between two belt conveyors heated at least one of them.

  Integration after superposing the breathable substrates can be achieved by applying pressure, and for example, a method of passing between pressurized rolls can be employed. The degree of pressurization may be appropriately set in consideration of the adhesive strength, the deodorizing agent crushing, the influence on air permeability, and the like.

  The air filter medium of the present invention is not particularly limited, but generally is subjected to pleating and used as an air filter. The pleating process is a mountain-folded folding process, and is preferable because the area of the air filter medium can be increased with respect to a certain ventilation area. The shape of the pleat is not particularly limited, and may be appropriately selected according to the use of the air filter.

  The air filter medium and the air filter of the present invention are used in various scenes such as general residential use, commercial use, automobiles and railway vehicles, air conditioners, air purifiers, vacuum cleaners, dehumidifiers, dryers, humidifiers. By installing and using in various air treatment devices such as a ventilation fan and a heat exchange device, an air cleaning effect such as dust removal and deodorization can be obtained. Moreover, you may use the air filter medium and air filter of this invention for the external airflow inlet (a vent hole, a window, etc.) for natural air supply / exhaust.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the examples. In the examples, “%” and “part” represent “% by mass” and “part by mass”, respectively, unless otherwise specified.

<Example 1>
(A) Selection of Breathable Substrate A The breathable substrate A has a basis weight mainly composed of polyester fibers of 60 g / m ² , a thickness of 0.8 mm, wind pressure resistance of 8.0 g for MD, and 6. g for CD. A 3 g chemical bond nonwoven fabric was selected.

(B) Selection of Breathable Substrate B As the breathable substrate B, a nonwoven fabric in which a high voltage was applied to a polypropylene nonwoven fabric having a basis weight of 16 g / m ² was selected.

(C) Preparation of Deodorant Layer After mixing 100 parts by mass of neutral unattached charcoal (granular activated carbon) with 100 parts by mass of alkaline impregnated charcoal (granular activated carbon), granular thermoplastic adhesive (softening point 100) 80 parts by mass of ethylene vinyl acetate resin powder (° C.) was mixed to prepare a mixed powder.

(D) Preparation of air filter medium The mixed powder 200 g / m ² prepared in (c) was spread on one surface of the breathable substrate A selected in (a). Heated by applying an infrared heater with a surface temperature of 150 ° C. from the spreading side, and then stopped after the granular thermoplastic adhesive was plasticized, and promptly the breathable base material selected in (b) on the mixed powder spreading side The air filter medium of Example 1 was obtained by superimposing B, pressing between two rotating rolls, pressurizing them, and integrating them.

(E) Preparation of air filter Using the air filter medium prepared in (d), fold processing is performed with a fold mountain height of 26 mm, and a frame is attached to two top and bottom sides of the filter medium for 33 mountains, length 200 mm, width An air filter having a size of 200 mm, a height of 29 mm, and a crease interval of about 6 mm was produced.

<Example 2>
(A) In selecting the breathable base material A, the basis weight is 40 g / m ² based on polyester fiber, the thickness is 0.3 mm, the wind pressure resistance is 6.6 g in MD, and 4.5 g in CD. An air filter medium was prepared in the same manner as in Example 1 except that a bond nonwoven fabric was selected.

<Example 3>
(A) In selecting the breathable base material A, the basis weight is 100 g / m ² mainly composed of polyester fiber, the thickness is 0.8 mm, the wind pressure resistance is 10.5 g in MD, and 8.0 g in CD. An air filter medium was prepared in the same manner as in Example 1 except that a bond nonwoven fabric was selected.

<Example 4>
(A) In selecting the breathable base material A, the basis weight is 60 g / m ² consisting mainly of polyester fiber, the thickness is 1.2 mm, the wind pressure resistance is 10.8 g in MD, and 7.0 g in CD. An air filter medium was prepared in the same manner as in Example 1 except that a bond nonwoven fabric was selected.

<Example 5>
(A) In selecting the breathable base material A, the basis weight is 60 g / m ² based on polyester fiber, the thickness is 0.6 mm, the wind pressure resistance is 7.5 g for MD, and 5.5 g for CD. An air filter medium was prepared in the same manner as in Example 1 except that a bond nonwoven fabric was selected.

<Example 6>
(A) In selecting the breathable base material A, the basis weight is 60 g / m ² consisting mainly of polyester fiber, the thickness is 0.5 mm, the wind pressure resistance is 7.1 g in MD, and 5.0 g in CD. An air filter medium was prepared in the same manner as in Example 1 except that a bond nonwoven fabric was selected.

<Comparative Example 1>
(A) In selecting the breathable base material A, the basis weight is 60 g / m ² mainly composed of polyester fiber, the thickness is 0.6 mm, the wind pressure resistance is 6.3 g in MD, and 4.9 g in CD. An air filter medium was prepared in the same manner as in Example 1 except that a bond nonwoven fabric was selected.

<Comparative example 2>
(A) In selecting the breathable base material A, the basis weight is 60 g / m ² mainly composed of polyester fiber, the thickness is 0.6 mm, and the wind pressure resistance is 7.3 g in MD and 4.3 g in CD. An air filter medium was prepared in the same manner as in Example 1 except that a bond nonwoven fabric was selected.

<Comparative Example 3>
(A) In selecting the breathable base material A, the basis weight is 35 g / m ² , the thickness is 0.4 mm, the wind pressure resistance is 6.5 g MD and 4.5 g CD. An air filter medium was prepared in the same manner as in Example 1 except that a bond nonwoven fabric was selected.

<Comparative Example 4>
(A) In selecting the breathable base material A, the basis weight is 40 g / m ² consisting mainly of polyester fibers, the thickness is 0.2 mm, the wind pressure resistance is 6.6 g in MD, and 4.6 g in CD. An air filter medium was prepared in the same manner as in Example 1 except that a bond nonwoven fabric was selected.

<Comparative Example 5>
(A) In selecting the breathable base material A, the basis weight is 110 g / m ² mainly composed of polyester fiber, the thickness is 1.2 mm, the wind pressure resistance is 9.9 g in MD, and 7.2 g in CD. An air filter medium was prepared in the same manner as in Example 1 except that a bond nonwoven fabric was selected.

<Comparative Example 6>
(A) In selecting the breathable base material A, the basis weight is 115 g / m ² mainly composed of polyester fibers, the thickness is 1.5 mm, the wind pressure resistance is 10.5 g in MD, and 7.5 g in CD. An air filter medium was prepared in the same manner as in Example 1 except that a bond nonwoven fabric was selected.

<Comparative Example 7>
(D) In preparing the air filter medium, an air filter medium was prepared in the same manner as in Example 1 except that an infrared heater having a surface temperature of 180 ° C. was used when heating from the spreading side.

[Measurement of Gurley stiffness]
(A) For the breathable substrate A used above, using a test piece cut into MD88 mm length, CD25 mm width, MD25 mm width, CD88 mm length, in the Gurley stiffness test method described in JIS L 1085, After measuring the bending resistance of MD and CD, the average value of MD and CD was calculated.

[Observation of granular thermoplastic adhesive]
For the air filter medium produced above, the breathable base material A and the breathable base material B are carefully peeled by hand, and the peeled surface is observed with a magnifying glass, so that the granular thermoplastic adhesive maintains a granular shape. No, the state was judged.

  About Examples 1-6 and Comparative Examples 1-7, the physical property of the used air permeable base material A and the shape observation result of the granular thermoplastic adhesive after air filter medium preparation are shown in Table 1.

[Evaluation]
About the air filter medium produced above, pressure loss and pleat processability were evaluated as shown below. In addition, the pleated structure durability and dust holding capacity under high wind speed conditions were evaluated using the produced air filter.

(Test 1) Measurement of pressure loss According to JIS B 9908, the pressure loss (pressure loss) of the air filter medium obtained in (d) is measured at a wind speed of 10 cm / second, and the result is judged based on the following evaluation method. did.

○: Pressure loss is less than 13 Pa Δ: Pressure loss is 13 Pa or more and less than 15 Pa x: Pressure loss is 15 Pa or more

  In the present invention, Δ or more is regarded as a practical level.

(Test 2) Evaluation of pleat workability Using a pleat processing machine, the air filter medium was subjected to pleat processing of about 300 m at a peak height of 26 mm, and the pleatability (folding workability) of the filter medium was determined based on the following criteria. did.

○: No irregularities in height and meandering occur during processing of filter medium 300m, and can be processed without problems. Δ: Unevenness in height and meandering occur at least one time and less than three times during processing of filter medium 300m. Can be processed without problems. X: Unevenness of mountain height and meandering occurred 3 times or more during the processing of the filter medium 300 m, and stable pleating cannot be performed.

  In this test, Δ or more was regarded as a practical level.

(Test 3) Structural durability evaluation under high wind speed conditions Using a test apparatus according to JIS B 9908, the pleated structure when air was passed through the air filter obtained in (e) at a wind speed of 5.0 m / sec. The result of structural durability was determined based on the following criteria based on visual observation.

○: Disturbance is not observed in the pleated structure, or there are less than 2 places where the crease interval is less than 4 mm or 8 mm or more Δ: 2 or more places where the crease interval is less than 4 mm or 8 mm or more 4 Less than x seen: 4 or more places where the crease interval is less than 4 mm or 8 mm or more

  In the present invention, Δ or more is regarded as a practical level.

(Test 4) Dust retention capacity test The air filter obtained in (e) was subjected to a final pressure loss of 200 Pa under the condition of surface wind speed of 2.5 m / sec according to JIS B 9908 type 3; The dust retention capacity (DHC) until reaching the value was calculated, and the result was determined based on the following criteria.

○: 9 g / piece or more Δ: 8 g / piece or more and less than 9 g / piece ×: less than 8 g / piece

  In this test, Δ or more was regarded as a practical level.

  Table 2 shows the results of the above tests 1 to 4 for Examples 1 to 6 and Comparative Examples 1 to 7.

As is apparent from Table 2, a deodorant-enclosed air filter medium comprising a deodorant sandwiched between a breathable substrate A and a breathable substrate B and encapsulated with a granular thermoplastic adhesive, While the adhesive is scattered in a granular state, the breathable substrate A has a basis weight of 40 to 100 g / m ² , a thickness of 0.3 to 1.4 mm, and wind pressure resistance [unit: g ] Is 6.5 g or more in MD of the non-woven fabric, 4.5 g or more in the CD, and the air filter media of Examples 1 to 6 constituted by the non-woven fabric are at a practical level in any of Tests 1 to 4. Judgment was obtained.

From the results of Test 1, the air filter medium of Example 3 in which the basis weight of the breathable base material A was 100 g / m ² was slightly inferior to Example 1 in pressure loss, and Comparative Example 5 in which the basis weight was 110 g / m ² . In Comparative Example 6 with 115 g / m ² , the pressure loss did not reach the practical level of the present invention. This is considered to be derived from the fact that the air permeability of the air filter medium produced due to the large basis weight of the air permeable substrate A was lowered. Moreover, also in the comparative example 7 in which the thermoplastic adhesive did not maintain the granularity when the granular thermoplastic adhesive of the air filter medium was observed, the pressure loss did not reach the practical level of the present invention. Although the reason is not clear, it is considered that the granular thermoplastic adhesive melted and bonded in a state where the adhesive spreads more than in Example 1, resulting in a decrease in air permeability and an increase in pressure loss.

  From the results of Test 2, the air filter medium of Example 4 in which the thickness of the breathable substrate A was 1.2 mm was inferior to that of Example 1 in foldability, and the thickness was 1.5 mm. In the air filter medium of Example 6, a practical level of folding workability was not obtained.

  From the results of Test 3, in Example 2 and Example 6 in which the wind pressure resistance of the breathable base material A was low, the structural durability under high wind speed was inferior to that in Example 1, and the wind pressure resistance of MD was low. In Comparative Example 1 which was less than 6.5 g and Comparative Example 2 where the wind pressure resistance of CD was less than 4.5 g, the structural durability at the practical level of the present invention was not obtained.

From the results of Test 4, the air filter of Example 2 in which the basis weight of the breathable substrate A was 40 g / m ² , the thickness was 0.3 mm, the wind pressure resistance of MD was 6.6 g, and the wind pressure resistance of CD was 4.5 g. In the filter produced with the filter medium, the dust retention capacity was inferior to that of Example 1, and the air pressure resistance of MD of the breathable base material A was 6.3 g, Comparative Example 1, and the wind pressure resistance of CD was 4.3. In Comparative Example 2 in which the weight per unit area was 35 g / m ² and in Comparative Example 4 in which the thickness was 0.2 mm, the dust retention capacity of the air filter obtained was compared with the practical level of the present invention. did not become. The reason is not clear, but the air filter with low basis weight, thickness, or wind pressure resistance of the breathable base material A has a characteristic of low structural durability under high wind speed conditions under heavy dust load. And increased pressure loss due to pleated structure disturbance. In these air filters, the final pressure loss of 200 Pa, which is the end point of the test, is reached as a result, so it is considered that the dust holding capacity is reduced. In addition, the air filter of Example 3 in which the basis weight of the breathable substrate A was 100 g / m ² was inferior in dust holding capacity compared to Example 1, and the basis weight of the breathable substrate A was 110 g / m ² respectively. In the air filters of Comparative Example 5 and Comparative Example 6 which were m ² and 115 g / m ² , a practical level of dust holding capacity could not be obtained. The reason is not clear, but the air filter using the air filter medium having a high basis weight of the breathable base material A tends to have a high initial pressure loss, and the amount of dust that can be held by the final pressure loss at the end of the test is small. It is done.

  The air filter medium and the air filter of the present invention are used in various situations such as general residential use, commercial use, automobiles, railway vehicles, etc. It can be used for various air treatment devices such as a ventilation fan and a heat exchange device. Further, it can be used for an external air flow inlet (such as a vent or a window) for natural air supply and exhaust.

1 Filter medium 2 Base 3 Container 4 Weight 5 Resin tube

Claims (2)

A deodorant-enclosed air filter medium in which a deodorizer is sandwiched between a breathable substrate A and a breathable substrate B and encapsulated with a granular thermoplastic adhesive, wherein the thermoplastic adhesive maintains a granular state The air-permeable base material A has a basis weight of 40 to 100 g / m ² , a thickness of 0.3 to 1.4 mm, and a wind pressure resistance [unit: g] defined below is a nonwoven fabric. An air filter medium characterized in that it is 6.5 g or more in MD and 4.5 g or more in CD, and is composed of a nonwoven fabric.
Wind pressure resistance: Two pedestals (57 mm wide x 40 mm deep x 155 mm high, made of polystyrene) are fixed at a distance of 52 mm, and a non-woven fabric having a long side of 140 mm and a short side of 40 mm is placed between the top plates of the two pedestals. The long side direction and the width direction of the pedestal are passed in parallel, the container is suspended from the center line in the long side direction of the nonwoven fabric, the weight is gradually added to the container, and the "mass of the container at the time the container falls + Mass of weight is defined as “wind pressure resistance”.   An air filter comprising the air filter medium according to claim 1.